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United States Patent Application |
20040178383
|
Kind Code
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A1
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Kikuchi, Seiji
|
September 16, 2004
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Flame-retardant aromatic polycarbonate resin composition
Abstract
A flame retardant aromatic polycarbonate resin composition comprising:
(A) an aromatic polycarbonate resin (component A);
(B) an acrylonitrile-styrene copolymer (component B);
(C) inorganic fillers (components C);
(D) an organic phosphorus compound-based flame retardant (component D);
and
(E) a fluorine-containing anti-dripping agent (component E),
the amounts of the above components are specific and particularly the
components C consist of (C1) mica and (C2) talc and/or wollastonite in a
specific ratio,
and a molded article formed from the resin composition.
According to the present invention, there are provided a resin composition
which has excellent mechanical properties, flame retardancy and
dimensional stability, is light in weight and rarely wears away a mold
and a molded article of the resin composition.
Inventors: |
Kikuchi, Seiji; (Tokyo, JP)
|
Correspondence Address:
|
WENDEROTH, LIND & PONACK, L.L.P.
2033 K STREET N. W.
SUITE 800
WASHINGTON
DC
20006-1021
US
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Serial No.:
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478996 |
Series Code:
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10
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Filed:
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November 26, 2003 |
PCT Filed:
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March 27, 2003 |
PCT NO:
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PCT/JP03/03839 |
Current U.S. Class: |
252/62 |
Class at Publication: |
252/062 |
International Class: |
E04B 001/74 |
Foreign Application Data
Date | Code | Application Number |
Mar 27, 2002 | JP | 2002-088309 |
Claims
1. A flame retardant aromatic polycarbonate resin composition comprising:
(A) an aromatic polycarbonate resin (component A); (B) an
acrylonitrile-styrene copolymer (component B); (C) inorganic fillers
(components C); (D) an organic phosphorus compound-based flame retardant
(component D); and (E) a fluorine-containing anti-dripping agent
(component E), the amounts of the above components satisfying the
following conditions (i) to (iii): (i) the total amount of the components
A and B is 50 wt % or more, the total amount of the components C is 15 to
35 wt %, and the amount of the component D is 3 to 15 wt % based on 100
wt % of the total of the components A to D, and the amount of the
component E is 0.02 to 2 parts by weight based on 100 parts by weight of
the total of the components A to D; (ii) the amount of the component A is
75 to 95 parts by weight and the amount of the component B is 5 to 25
parts by weight based on 100 parts by weight of the total of the
components A and B; and (iii) the components C consist of (C1) mica
having an average particle diameter of 30 to 300 .mu.m (component C-1)
and (C2) at least one filler (component C-2) selected from the group
consisting of talc and wollastonite, the amount of the component C-1 is
10 to 25 wt % and the amount of the component C-2 is 3 to 15 wt % based
on 100 wt % of the total of the components A to D, and the amount of the
component C-1 is 40 to 90 parts by weight based on 100 parts by weight of
the total of the components C-1 and C-2.
2. A flame retardant aromatic polycarbonate resin composition comprising:
(A) an aromatic polycarbonate resin (component A); (B) an
acrylonitrile-styrene copolymer (component B); (C) inorganic fillers
(components C); (D) an organic phosphorus compound-based flame retardant
(component D); (E) a fluorine-containing anti-dripping agent (component
E); and (F) a higher fatty acid ester of a monohydric or polyhydric
alcohol (component F), the amounts of the above components satisfying the
following conditions (i) to (iii): (i) the total amount of the components
A and B is 50 wt % or more, the total amount of the components C is 15 to
35 wt %, and the amount of the component D is 3 to 15 wt % based on 100
wt % of the total of the components A to D, and the amount of the
component E is 0.02 to 2 parts by weight and the amount of the component
F is 0.01 to 2 parts by weight based on 100 parts by weight of the total
of the components A to D; (ii) the amount of the component A is 75 to 95
parts by weight and the amount of the component B is 5 to 25 parts by
weight based on 100 parts by weight of the total of the components A and
B; and (iii) the components C consist of (C1) mica having an average
particle diameter of 30 to 300 .mu.m (component C-1) and (C2) at least
one filler (component C-2) selected from the group consisting of talc and
wollastonite, the amount of the component C-1 is 10 to 20 wt % and the
amount of the component C-2 is 5 to 15 wt % based on 100 wt % of the
total of the components A to D, and the amount of the component C-1 is 40
to 90 parts by weight based on 100 parts by weight of the total of the
components C-1 and C-2.
3. The resin composition of claim 1 or 2, wherein the component C-2 is
talc having an average particle diameter of 0.5 to 30 .mu.m.
4. The resin composition of claim 1 or 2 which provides a molded article
having a shrinkage anisotropy of 0.15 or less and an impact strength of
30 J/m or more.
5. The resin composition of claim 1 or 2 which provides a molded article
having V-1 rating in the UL94 flame retardancy test of a 1.6 mm-thick
test specimen.
6. The resin composition of claim 1 or 2 which provides a molded article
having resistance to low-viscosity lubricating oil.
7. The resin composition of claim 1 or 2 which provides a molded article
having a true density of 1.3 to 1.45 (g/cm.sup.3).
8. The resin composition of claim 1 or 2, wherein the
acrylonitrile-styrene copolymer (component B) has a weight average
molecular weight of 40,000 to 200,000.
9. The resin composition of claim 1 or 2, wherein the
acrylonitrile-styrene copolymer (component B) contains an acrylonitrile
component and a styrene component in a weight ratio of 5:95 to 50:50.
10. The resin composition of claim 1 or 2, wherein mica (component C-1)
out of the inorganic fillers (components C) has an average particle
diameter of 30 to 280 .mu.m.
11. The resin composition of claim 1 or 2, wherein the organic phosphorus
compound-based flame retardant (component D) is an organic phosphate.
12. The resin composition of claim 1 or 2, wherein the organic phosphorus
compound-based flame retardant (component D) has a 5% weight reduction
temperature of 280 to 380.degree. C.
13. The resin composition of claim 1 or 2, wherein the total amount of the
components A and B is 60 wt % or more, the total amount of the components
C is 20 to 30 wt %, and the amount of the component D is 3 to 10 wt %
based on 100 wt % of the total of the components A to D, and the amount
of the component E is 0.1 to 1 part by weight based on 100 parts by
weight of the total of the components A to D.
14. The resin composition of claim 1 or 2, wherein the amount of the
component A is 78 to 92 parts by weight and the amount of the component B
is 8 to 22 parts by weight based on 100 parts by weight of the total of
the components A and B.
15. The resin composition of claim 1 or 2, wherein the amount of mica
(component C-1) is 12 to 20 wt % and the amount of the component C-2 is 5
to 12 wt % based on 100 wt % of the total of the components A to D, and
the amount of the component C-1 is 50 to 80 parts by weight based on 100
parts by weight of the total of the components C-1 and C-2.
16. A molded article formed from the resin composition of claim 1 or 2.
17. A chassis or frame molded article formed from the resin composition of
claim 1 or 2.
18. A flame retardant aromatic polyphenylene ether resin composition
comprising: (1) a polyphenylene ether resin (component P); (2) a
polystyrene resin (component S); (3) inorganic fillers (components C);
(4) an organic phosphorus compound-based flame retardant (component D);
and (5) a fluorine-containing anti-dripping agent (component E), the
amounts of the above components satisfying the following conditions (i)
to (iii): (i) the total amount of the components P and S is 50 wt % or
more, the total amount of the components C is 15 to 35 wt %, and the
amount of the component D is 3 to 15 wt % based on 100 wt % of the total
of the components P, S, C and D, and the amount of the component E is 0
to 2-parts by weight based on 100 parts by weight of the total of the
components P, S, C and D; (ii) the amount of the component P is 50 to 85
parts by weight and the amount of the component S is 15 to 50 parts by
weight based on 100 parts by weight of the total of the components P and
S; and (iii) the components C consist of (C1) mica having an average
particle diameter of 30 to 300 .mu.m (component C-1) and (C2) at least
one filler (component C-2) selected from the group consisting of talc and
wollastonite, the amount of the component C-1 is 10 to 25 wt % and the
amount of the component C-2 is 3 to 15 wt % based on 100 wt % of the
total of the components P, S, C and D, and the amount of the component
C-1 is 40 to 90 parts by weight based on 100 parts by weight of the total
of the components C-1 and C-2.
19. The resin composition of claim 18 which provides a molded article
having a shrinkage anisotropy of 0.15 or less, an impact strength of 25
J/m or more, V-1 rating in the UL94 flame retardancy test of a 20
mm-thick test specimen and a true density of 1.2 to 1.35 (g/cm.sup.3).
20. The resin composition of claim 18, wherein the polyphenylene ether
resin (component P) has a reduced viscosity measured in a 0.5 g/dl
chloroform solution at 30.degree. C. of 0.20 to 0.70 dl/g.
21. The resin composition of claim 18, wherein the total amount of the
components P and S is 60 wt % or more, the total amount of the components
C is 20 to 30 wt % and the amount of the component D is 5 to 12 wt %
based on 100 wt % of the total of the components P, S, C and D, and the
amount of the component E is 0.05 to 2 parts by weight based on 100 parts
by weight of the total of the components P, S, C and D.
22. The resin composition of claim 18, wherein the amount of the component
P is 55 to 75 parts by weight and the amount of the component S is 25 to
45 parts by weight based on 100 parts by weight of the total of the
components P and S.
23. The resin composition of claim 18, wherein the amount of mica
(component C-1) is 12 to 20 wt % and the amount of the component C-2 is 5
to 12 wt % based on 100 wt % of the total of the components P, S, C and
D, and the amount of the component C-1 is 50 to 80 parts by weight based
on 100 parts by weight of the total of the components C-1 and C-2.
24. A molded article formed from the resin composition of claim 18.
25. A chassis or frame molded article formed from the resin composition of
claim 18.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a flame retardant aromatic
polycarbonate resin composition. More specifically, it relates to a resin
composition which comprises (i) resin components including an aromatic
polycarbonate resin as the main resin component and a small amount of an
acrylonitrile-styrene copolymer, (ii) inorganic fillers including mica
having a predetermined particle diameter (C-1) and talc and/or
wollastonite (C-2), (iii) an organic phosphorus compound as a flame
retardant and (iv) a fluorine-containing compound as a anti-dripping
agent, provides (a) a molded article having high stiffness, strength and
dimensional accuracy, has (b) satisfactory flame retardancy in spite of a
relatively small amount of the flame retardant, and (c) rarely wears away
a mold though the inorganic fillers are contained. The resin composition
of the present invention is suitable for molding parts which need flame
retardancy and high dimensional accuracy, such as chassis and frames.
[0003] 2. Description of Prior Art
[0004] High stiffness, strength and dimensional accuracy (low anisotropy)
and excellent flame retardancy are required for plastic materials for use
in the chassis or frames (may be simply referred to as "optical unit
chassis" hereinafter) of apparatuses having an optical unit, such as
laser beam printers, copying machines and projectors. A large number of
proposals have already been made for the plastic materials for chassis.
Low anisotropy is still strongly required for optical unit chassis. The
above various apparatuses having an optical unit have been manufactured
for a long time and a lot of know-how has already been accumulated. In
the field of the apparatuses having an optical unit under the above
situation, new models having higher performance have been developed
whereas general-purpose models have been improved, placing stress on a
reduction in cost. In this case, plastic materials may have problems with
cost required for their molds and the service lives of the molds. That
is, a material which rarely wears away a mold (to be referred to as "low
mold wearability" hereinafter) is sought for.
[0005] A large number of resin compositions suitable for use as molded
parts such as chassis and frames have been proposed up till now. (i) JP-A
5-287185 (the term "JP-A" as used herein means an "unexamined published
Japanese patent application") discloses a resin composition prepared by
loading an aromatic polycarbonate resin having a specific molecular
weight with a large amount of a glass fiber or the like. And, (ii) JP-A
6-207189 discloses a resin composition which comprises an aromatic
polycarbonate resin having a specific molecular weight, a fiber having a
non-circular section and a lamellar inorganic filler and achieves low
warpage. Further, (iii) JP-A 9-12733 discloses an optical write unit
fixing chassis formed from a resin composition which comprises an
aromatic polycarbonate resin and mica having a specific particle diameter
and a specific thickness. The invention disclosed by JP-A 9-12733 has
high stiffness, low warpage and torsion based on low anisotropy, and
excellent flame retardancy. That is., it has favorable characteristic
properties required for optical unit chassis. However, it is hardly said
that molded articles which satisfy all the requirements such as high
stiffness, high strength, low anisotropy (high dimensional accuracy),
flame retardancy and low mold wearability are obtained from the
composition of this invention.
[0006] JP-A 1-185360 discloses a resin composition which comprises an
aromatic polycarbonate, polycaprolactone and carbon fiber and teaches
that the composition has reduced mold wearability. However, the invention
disclosed by the above publication does not take into full consideration
low anisotropy and fails to disclose technical information on how
sufficiently high strength is retained after low anisotropy is achieved.
[0007] JP-A 8-115589 discloses a CD-ROM part which comprises a
polycarbonate resin, flaky inorganic filler and phosphate compound having
a specific structure. However, it is hardly said that the publication
discloses a resin composition which satisfies all the requirements such
as high stiffness, high strength, excellent flame retardancy and low mold
wearability.
[0008] JP-A 2001-164105 discloses a resin composition which comprises an
aromatic polycarbonate resin, flame retardant, inorganic filler which
consists of a glass fiber and talc in a specific ratio and
polytetrafluoroethylene having fibril forming capability and teaches that
the composition has high stiffness, strength and dimensional accuracy and
excellent flame retardancy. However, the composition has room for further
improvement as a material for use in models with greater importance
attached to a cost reduction.
SUMMARY OF THE INVENTION
[0009] It is an object of the present invention to provide an aromatic
polycarbonate resin composition which is particularly suitable for use as
an optical unit chassis or frame molded article and which satisfies all
the requirements such as high stiffness, strength and dimensional
accuracy (low anisotropy), excellent flame retardancy and low mold
wearability in a well-balanced manner.
[0010] The inventor of the present invention has conducted intensive
studies to attain the above object and has found that a molded article
which can attain the object of the present invention can be obtained from
a resin composition which comprises a combination of an aromatic
polycarbonate resin and a specific amount of an acrylonitrile-styrene
copolymer (AS resin) as resin components, a combination of mica having a
specific particle diameter and talc or wollastonite in a specific ratio
as inorganic fillers, an organic phosphorus compound as a flame retardant
and a fluorine-containing anti-dripping agent in a specific ratio. That
is, it has been found that the resin composition provides a molded
article having high stiffness, strength and dimensional accuracy, that
excellent flame retardancy is obtained by using a relatively small amount
of a flame retardant and that the wearability of a mold is extremely low.
[0011] Means for Solving the Problems
[0012] According to the present invention, there is provided a flame
retardant aromatic polycarbonate resin composition comprising:
[0013] (A) an aromatic polycarbonate resin (component A);
[0014] (B) an acrylonitrile-styrene copolymer (component B);
[0015] (C) inorganic fillers (components C);
[0016] (D) an organic phosphorus compound-based flame retardant (component
D); and
[0017] (E) a fluorine-containing anti-dripping agent (component E),
[0018] the amounts of the above components satisfying the following
conditions (i) to (iii).
[0019] (i) The total amount of the components A and B is 50 wt % or more,
the total amount of the components C is 15 to 35 wt % and the amount of
the component D is 3 to 15 wt % based on 100 wt % of the total of the
components A to D, and the amount of the component E is 0.02 to 2 parts
by weight based on 100 parts by weight of the total of the component A to
D;
[0020] (ii) the amount of the component A is 75 to 95 parts by weight and
the amount of the component B is 5 to 25 parts by weight based on 100
parts by weight of the total of the components A and B; and
[0021] (iii) the components C consist of (C1) mica having an average
particle diameter of 30 to 300 .mu.m (component C-1) and (C2) at least
one filler (component C-2) selected from the group consisting of talc and
wollastonite, the amount of the component C-1 is 10 to 25 wt % and the
amount of the component C-2 is 3 to 15 wt % based on 100 wt % of the
total of the components A to D, and the amount of the component C-1 is 40
to 90 parts by weight based on 100 parts by weight of the total of the
components C-1 and C-2.
[0022] The inventor of the present invention has conducted further studies
and has found that when a predetermined amount of a higher fatty acid
ester of a monohydric or polyhydric alcohol (component F) is mixed with
the resin composition as a release agent, releasability from a mold
becomes extremely excellent compared with when different types of release
agents are mixed.
[0023] Thus, according to the present invention, there is also provided a
flame retardant aromatic polycarbonate resin composition comprising:
[0024] (A) an aromatic polycarbonate resin (component A);
[0025] (B) an acrylonitrile-styrene copolymer (component B);
[0026] (C) inorganic fillers (components C);
[0027] (D) an organic phosphorus compound-based flame retardant (component
D);
[0028] (E) a fluorine-containing anti-dripping agent (component E); and
[0029] (F) a higher fatty acid ester of a monohydric or polyhydric alcohol
(component F),
[0030] the amounts of the above components satisfying the following
conditions (i) to (iii).
[0031] (i) The total amount of the components A and B is 50 wt % or more,
the total amount of the components C is 15 to 35 wt %, and the amount of
the component D is 3 to 15 wt % based on 100 wt % of the total of the
components A to D, and the amount of the component E is 0.02 to 2 parts
by weight and the amount of the component F is 0.01 to 2 parts by weight
based on 100 parts by weight of the total of the components A to D;
[0032] (ii) the amount of the component A is 75 to 95 parts by weight and
the amount of the component B is 5 to 25 parts by weight based on 100
parts by weight of the total of the components A and B; and
[0033] (iii) the components C consist of (C1) mica having an average
particle diameter of 30 to 300 .mu.m (component C-1) and (C2) at least
one filler (component C-2) selected from the group consisting of talc and
wollastonite, the amount of the component C-1 is 10 to 20 wt % and the
amount of the component C-2 is 5 to 15 wt % based on 100 wt % of the
total of the components A to D, and the amount of the component C-1 is 40
to 90 parts by weight based on 100 parts by weight of the total of the
components C-1 and C-2.
[0034] A detailed description is given of the resin composition of the
present invention. Each component forming the resin composition is first
described.
[0035] In the resin composition of the present invention, the resin
components substantially consist of an aromatic polycarbonate resin
(component A) and an acrylonitrile-styrene copolymer (component B). The
acrylonitrile-styrene copolymer as the component B is generally called
"AS resin".
[0036] The aromatic polycarbonate resin as the component A may be an
aromatic polycarbonate resin known per se which has been used in various
molded articles. That is, it is obtained by reacting a diphenol with a
carbonate precursor. The reaction method is an interfacial polymerization
method, melt ester exchange method, carbonate prepolymer solid-phase
ester exchange method, or cyclic carbonate compound ring-opening
polymerization method.
[0037] Typical examples of the diphenol include 2,2-bis(4-hydroxyphenyl)pr-
opane (so-called bisphenol A), 2,2-bis{(4-hydroxy-3-methyl)phenyl}propane,
2,2-bis(4-hydroxyphenyl)butane, 2,2-bis(4-hydroxyphenyl)-3-methylbutane,
9,9-bis{(4-hydroxy-3-methyl)phenyl}fluorene, 2,2-bis(4-hydroxyophenyl)-3,-
3-dimethylbutane, 2,2-bis(4-hydroxyphenyl)-4-methylpentane,
1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane and
.alpha.,.alpha.'-bis(4-hydroxyphenyl)-m-diisopropylbenzene. A divalent
aliphatic alcohol such as 1,4-cyclohexanedimethanol may also be
copolymerized. Out of aromatic polycarbonate resins obtained from the
above diphenols, a homopolymer of bisphenol A is particularly preferred.
The aromatic polycarbonate resin is preferred because it is excellent in
impact resistance.
[0038] The carbonate precursor is a carbonyl halide, carbonate ester,
haloformate or the like, as exemplified by phosgene, diphenyl carbonate
and dihaloformate of a diphenol.
[0039] To produce an aromatic polycarbonate resin by reacting the above
diphenol with the above carbonate precursor in accordance with the
interfacial polycondensation or melt ester exchange method, a catalyst,
terminal capping agent and antioxidant for preventing the oxidation of
the diphenol may be optionally used. The aromatic polycarbonate resin may
be a branched polycarbonate containing a polyfunctional aromatic compound
having a functionality of 3 or more. Examples of the polyfunctional
aromatic compound having a functionality of 3 or more include
1,1,1-tris(4-hydroxyphenyl)ethane and 1,1,1-tris(3,5-dimethyl-4-hydroxyph-
enyl)ethane.
[0040] When a polyfunctional compound for forming a branched polycarbonate
is contained, the amount thereof is 0.001 to 1 mol %, preferably 0.005 to
0.5 mol %, particularly preferably 0.01 to 0.3 mol % based on the
aromatic polycarbonate resin. Particularly in the case of the melt ester
exchange method, a branched structure may be formed by a side reaction.
The amount of the branched structure is 0.001 to 1 mol %, preferably
0.005 to 0.5 mol %, particularly preferably 0.01 to 0.3 mol % based on
the aromatic polycarbonate resin. This amount can be calculated by
.sup.1H-NMR measurement.
[0041] Further, the aromatic polycarbonate resin of the present invention
may be a polyester carbonate resin containing an aromatic or aliphatic
dicarboxylic acid. The aliphatic dicarboxylic acid is, for example, an
aliphatic dicarboxylic acid having 8 to 20 carbon atoms, preferably 10 to
12 carbon atoms. The aliphatic dicarboxylic acid may be linear, branched
or cyclic. The aliphatic dicarboxylic acid is preferably an
.alpha.,.omega.-dicarboxylic acid. Preferred examples of the aliphatic
dicarboxylic acid include linear saturated aliphatic dicarboxylic acids
such as sebacic acid (decanoic diacid), dodecanoic diacid, tetradecanoic
diacid, octadecanoic diacid and icosanoic diacid.
[0042] A polycarbonate-polyorganosiloxane copolymer containing a
polyorganosiloxane unit may also be used.
[0043] The aromatic polycarbonate resin may be a mixture of two or more
aromatic polycarbonates selected from polycarbonates obtained from
different diphenols, branched polycarbonates having a branched component,
polyester carbonates and polycarbonate-polyorganosiloxane copolymers.
Further, it may be a mixture of two or more selected from aromatic
polycarbonates produced by the following different methods and aromatic
polycarbonates produced by using different terminal capping agents.
[0044] The polymerization reaction of an aromatic polycarbonate by the
interfacial polycondensation method is generally a reaction between a
diphenol and phosgene in the presence of an acid binder and an organic
solvent. As the acid binder is used an alkali metal hydroxide such as
sodium hydroxide or potassium hydroxide, or amine compound such as
pyridine. As the organic solvent is used a halogenated hydrocarbon such
as methylene chloride or chlorobenzene. A tertiary amine, quaternary
ammonium compound or quaternary phosphonium compound such as
triethylamine, tetra-n-butylammonium bromide or tetra-n-butylphosphonium
bromide may be used as a catalyst to promote the reaction. The reaction
temperature is generally 0 to 40.degree. C., the reaction time is 10
minutes to 5 hours, and pH during the reaction is preferably maintained
at 9 or more.
[0045] A terminal capping agent is generally used in the polymerization
reaction. A monofunctional phenol may be used as the terminal capping
agent. Examples of the monofunctional phenol include phenol,
p-tert-butylphenol, p-cumylphenol and isooctylphenol. These terminal
capping agents may be used alone or in combination of two or more.
[0046] The reaction carried out by the melt ester exchange method is
generally an ester exchange reaction between a diphenol and a carbonate
ester which is carried out in the presence of an inert gas by mixing
together the diphenol and the carbonate ester under heating and
distilling off the formed alcohol or phenol. The reaction temperature,
which changes according to the boiling point or the like of the formed
alcohol or phenol, is generally 120 to 350.degree. C. In the latter stage
of the reaction, the pressure of the reaction system is reduced to
1.33.times.10.sup.3 to 13.3 Pa to facilitate the distillation off of the
formed alcohol or phenol. The reaction time is generally about 1 to 4
hours.
[0047] The carbonate ester is an ester such as an aryl group or an aralkyl
group having 6 to 10 carbon atoms which may be substituted, or an alkyl
group having 1 to 4 carbon atoms. Of these, diphenylcarbonate is
preferable.
[0048] To accelerate the rate of polymerization, a polymerization catalyst
may be used. Examples of the polymerization catalyst include alkali metal
compounds such as sodium hydroxide, potassium hydroxide, and sodium salts
and potassium salts of a diphenol; alkali earth metal compounds such as
calcium hydroxide, barium hydroxide and magnesium hydroxide; and
nitrogen-containing basic compounds such as tetramethylammonium
hydroxide, tetraethylammonium hydroxide, trimethylamine and
triethylamine. Further, catalysts which are generally used for an
esterification reaction or ester exchange reaction, such as alkoxides and
organic acid salts of an alkali (earth) metal, boron compounds, germanium
compounds, antimony compounds, titanium compounds and zirconium compounds
may also be used. The catalysts may be used alone or in combination of
two or more. The amount of the polymerization catalyst is preferably
1.times.10.sup.-8 to 1.times.10.sup.-3 equivalent, more preferably
1.times.10.sup.-7 to 5.times.10.sup.-4 equivalent based on 1 mol of the
diphenol as a raw material.
[0049] In the reaction carried out by the melt ester exchange method, to
reduce the number of phenolic terminal groups of the aromatic
polycarbonate resin, a compound such as 2-chlorophenylphenyl carbonate,
2-methoxycarbonylphenylphenyl carbonate or 2-ethoxycarbonylphenylphenyl
carbonate may be added in the latter stage of a polycondensation reaction
or after the end of the polycondensation reaction.
[0050] Further, a deactivator for neutralizing the activity of the
catalyst is preferably used in the melt ester exchange method. The
deactivator is preferably used in an amount of 0.5 to 50 mols based on 1
mol of the residual catalyst. Or it is used in an amount of 0.01 to 500
ppm, preferably 0.01 to 300 ppm, particularly preferably 0.01 to 100 ppm
based on the aromatic polycarbonate resin after polymerization. Preferred
examples of the deactivator include phosphonium salts such as
tetrabutylphosphonium dodecylbenzene sulfonate and ammonium salts such as
tetraethylammonium dodecylbenzyl sulfonate.
[0051] The viscosity average molecular weight of the aromatic
polycarbonate resin is not particularly limited but preferably 15,000 to
50,000 in the present invention. The lower limit of the viscosity average
molecular weight is preferably 16,000, more preferably 17,000,
particularly preferably 18,000. The upper limit of the viscosity average
molecular weight is preferably 26,000, more preferably 25,000. The above
viscosity average molecular weight is particularly preferred when the
aromatic polycarbonate resin is contained in an amount of 50 wt % or
more, preferably 70 wt % or more based on 100 wt % of the component A.
When the viscosity average molecular weight of the aromatic polycarbonate
is lower than 15,000, impact strength and flame retardancy are apt to
deteriorate. When the viscosity average molecular weight is higher than
50,000, fluidity lowers which is not preferred in the present invention.
[0052] Two or more aromatic polycarbonates may be used in combination. In
this case, it is naturally possible to mix a polycarbonate resin having a
viscosity average molecular weight outside the above range.
[0053] A mixture of an aromatic polycarbonate having a viscosity average
molecular weight higher than 50,000 has satisfactory melt tension due to
high entropy elasticity. Accordingly, it has favorable properties for
forming a colored layer. When it is used as a component of a substrate
layer, it hardly causes a molding failure based on rheology behavior
typified by the prevention of jetting, gas assist stability and foaming
stability.
[0054] A mixture with an aromatic polycarbonate resin having a viscosity
average molecular weight of 80,000 or more is preferred and a mixture
with an aromatic polycarbonate resin having a viscosity average molecular
weight of 100,000 or more is more preferred. That is, a mixture whose
molecular weight distribution has two or more peaks observed by a
measurement method such as GPC (Gel Permeation Chromatography) can be
preferably used.
[0055] In the aromatic polycarbonate resin (component A) of the present
invention, the amount of its phenolic hydroxyl group is preferably 30
eq/ton or less, more preferably 25 eq/ton or less, much more preferably
20 eq/ton or less. It is possible to reduce the above value to 0 eq/ton
substantially by fully reacting a terminal capping agent. The amount of
the phenolic hydroxyl group based on the weight of the polymer is
obtained by calculating the molar ratio of a diphenol unit having a
carbonate bond, a diphenol unit having a phenolic hydroxyl group and the
unit of the terminal capping agent by .sup.1H-NMR measurement.
[0056] The viscosity average molecular weight (M) of the component A as
used herein is obtained by first obtaining a specific viscosity
calculated from the following equation using a solution of 0.7 g of an
aromatic polycarbonate resin dissolved in 100 ml of methylene chloride at
20.degree. C. with an Ostwald viscometer,
Specific viscosity (.eta.sp)=(t-t.sub.0)/t.sub.0
[0057] [t.sub.0 is the number of seconds required for dropping methylene
chloride and t is the number of seconds required for dropping a sample
solution]
[0058] and inserting the obtained specific viscosity into the following
equation.
.eta.sp/c=[.eta.]+0.45.times.[.eta.].sup.2c ([.eta.] is an intrinsic
viscosity)
[0059] [.eta.]=1.23.times.10.sup.-4 M.sup.0.83
[0060] c=0.7
[0061] The component A of the present invention may be a mixture of two or
more polycarbonates, such as a mixture of polycarbonates which are
obtained from different diphenols, a mixture of a polycarbonate obtained
by using a terminal capping agent and a polycarbonate obtained by using
no terminal capping agent, a mixture of a linear polycarbonate and a
branched polycarbonate, a mixture of polycarbonates manufactured by
different processes, a mixture of polycarbonates which are obtained by
using different terminal capping agents, a mixture of a polycarbonate and
a polyester carbonate, or a mixture of polycarbonates which differ from
each other in viscosity average molecular weight.
[0062] In the resin composition of the present invention, the component B
which is a resin component like the component A is an
acrylonitrile-styrene copolymer generally called "AS resin". As for the
amount of each component (monomer) in the copolymer (AS resin) as the
component B, the amount of acrylonitrile is 5 to 50 wt %, preferably 15
to 35 wt % and the amount of styrene is 95 to 50 wt %, preferably 85 to
65 wt % based on 100 wt % of the whole resin. The copolymer as the
component B may contain a small amount of a copolymerizable vinyl
compound other than acrylonitrile and styrene. The amount of the vinyl
compound is 15 wt % or less, preferably 10 wt % or less based on the
component B. A conventionally known polymerization initiator or chain
transfer agent used for the polymerization reaction of the component B
may be optionally used.
[0063] The component B (AS resin) may be manufactured by bulk
polymerization, solution polymerization, suspension polymerization or
emulsion polymerization, preferably bulk polymerization or suspension
polymerization. Copolymerization may be either one-stage copolymerization
or multi-stage copolymerization. The weight average molecular weight
measured by GPC in terms of standard polystyrene of the component B (AS
resin) is preferably 40,000 to 200,000. Its lower limit is preferably
50,000, more preferably 70,000. Its upper limit is preferably 160,000,
more preferably 150,000.
[0064] The resin composition of the present invention is characterized in
that two different types of inorganic fillers (components C) are used in
combination. One of the inorganic fillers (components C) is mica having a
specific average particle diameter (component C-1) and the other is at
least one (component C-2) selected from the group consisting of talc and
wollastonite.
[0065] The average particle diameter of mica (component C-1) as an
inorganic filler is a number average particle diameter obtained by
observing through a scanning electron microscope and averaging the
particle diameters of 1,000 particles sampled at random. The number
average particle diameter of mica is 30 to 300 .mu.m, preferably 30 to
280 .mu.m, more preferably 35 to 260 .mu.m. When the number average
particle diameter is smaller than 30 .mu.m, the impact strength lowers
and the thermal stability of the aromatic polycarbonate resin may
deteriorate When the number average particle diameter is larger than 300
.mu.m, the impact strength improves but the appearance is apt to
deteriorate. The deteriorated appearance reduces the slipperiness of a
member through which paper passes, which may not be preferred in a case.
[0066] Even when the average particle diameter of mica is within the range
of the present invention, its preferred range differs according to which
importance is attached to appearance or impact strength/stiffness. When
importance is attached to appearance, the number average particle
diameter of mica is in the range of preferably 30 to 100 .mu.m, more
preferably 35 to 80 .mu.m. The resin composition of the present invention
may be molded at a very low mold temperature to realize a cost reduction
by shortening the molding time. Therefore, to suppress a reduction in
slipperiness caused by the deteriorated appearance, mica having a smaller
particle diameter is suitably used. When importance is not attached to
appearance, mica having an average particle diameter of preferably 100 to
300 .mu.m, more preferably 100 to 260 .mu.m is used from the viewpoints
of stiffness and impact strength.
[0067] The thickness actually measured by observation through an electron
microscope of mica (component C-1) is 0.01 to 10 .mu.m, preferably 0.1 to
5 .mu.m. Mica having an aspect ratio of 5 to 200, preferably 10 to 100
may be used. The used mica (component C-1) is preferably muscovite mica
having a Mohs hardness of about 3. Muscovite mica has higher stiffness
and strength than other mica such as phlogopite and can attain the object
of the present invention at a high level.
[0068] As means of grinding mica, there are available a dry grinding
method in which a mica ore is ground by a dry grinder and a wet grinding
method in which a mica ore is roughly ground by a dry grinder, a grinding
aid such as water is added to grind a slurry of mica by a wet grinder,
and then dehydration and drying are carried out. The mica of the present
invention may be manufactured by either one of the above grinding methods
but the dry grinding method is generally used because it is more
inexpensive. The wet grinding method is effective in grinding mica into
finer and thinner particles but expensive. Mica may be surface treated
with a surface treating agent such as a silane coupling agent, higher
fatty acid ester or wax, and further granulated with a binder such as a
resin, higher fatty acid ester or wax.
[0069] The component C-2 which is used in combination with the above mica
(component c-1) as an inorganic filler is talc and/or wollastonite. Talc
used as the component C-2 is a flaky particle having a lamellar structure
and hydrous magnesium silicate in terms of chemical composition generally
represented by the chemical formula 4SiO.sub.2.3MgO.2H.sub.2O which
contains 56 to 65 wt % of SiO.sub.2, 28 to 35 wt % of MgO and about 5 wt
% of H.sub.2O. It further contains 0.03 to 1.2 wt % of Fe.sub.2O.sub.3,
0.05 to 1.5 wt % of Al.sub.2O.sub.3, 0.05 to 1.2 wt % of CaO, 0.2 wt % or
less of K.sub.2O and 0.2 wt % or less of Na.sub.2O as other trace
components and has a specific gravity of about 2.7 and a Mohs hardness of
1. In the present invention, when mica having a specific particle
diameter (component C-1) is used in combination with talc (component
C-2), a flame retardant resin composition having excellent flame
retardancy is obtained. It has been unknown that an excellent flame
retardant resin composition can be obtained by using a combination of
mica having a specific particle diameter and talc as lamellar inorganic
fillers.
[0070] The average particle diameter of talc is preferably 0.5 to 30
.mu.m. The average particle diameter is a particle diameter at an
integration rate of 50% obtained from a grain size distribution measured
by an Andreasen pipet method in accordance with JIS M8016. The particle
diameter of talc is preferably 2 to 30 .mu.m, more preferably 5 to 20
.mu.m, particularly preferably 10 to 20 .mu.m. When the particle diameter
is within the range of 0.5 to 30 .mu.m, excellent flame retardancy is
obtained.
[0071] The method of producing talc by milling an ore is not particularly
limited. An axial mill, annular mill, roll mill, ball mill, jet mill and
container rolling compression shear mill may be used. Further, milled
talc is classified by a classifier to obtain particles having a uniform
particle size distribution. The classifier is not particularly limited
and may be an impactor type inertia classifier (such as a Variable
impactor), utilizing Coanda effect type inertia classifier (such as an
Elbow jet), centrifugal classifier (such as multi-stage cyclone,
Microplex, dispersion separator, Acucut, Turbo Classifier, Turboplex,
Micron Separator or Super Separator).
[0072] Talc in an agglomerated state is preferred from the viewpoint of
handling ease and the like. To manufacture this type of talc, a method in
which deaeration compaction is used and a method in which a binder is
used for compaction may be used. The method making use of deaeration
compaction is preferred because it is simple and an unrequired binder
resin component is not contained in the resin composition of the present
invention.
[0073] Wollastonite as the component C-2 is substantially represented by
the chemical formula CaSiO.sub.3 and contains about 50 wt % or more of
SiO.sub.2, about 47 wt % of CaO, Fe.sub.2O.sub.3, Al.sub.2O.sub.3 and the
like. Wollastonite is a white needle-like powder obtained by grinding a
wollastonite ore and classifying the obtained particles and has a Mohs
hardness of about 4.5. The average fiber diameter of wollastonite in use
is preferably 0.5 to 10 .mu.m, more preferably 1 to 5 .mu.m. The average
fiber diameter is obtained by observing through a scanning electron
microscope and averaging the fiber diameters of 1,000 fibers sampled at
random.
[0074] Out of the above components C-2, talc is more preferred because it
has lower mold wearability. That is, the inorganic fillers (components C)
preferably consist of mica (component C-1) and talc (component C-2), and
the ratio of the component C-1 to the component C-2 will be described
hereinafter.
[0075] The resin composition of the present invention comprises an organic
phosphorus compound-based flame retardant (component D) as the flame
retardant. Use of a relatively small amount of the organic phosphorus
compound-based flame retardant (component D) makes it possible to provide
excellent flame retardancy to a molded article and improve stiffness
(flexural modulus) as well as to reduce specific gravity as compared with
a halogen-based flame retardant. In addition, the low melt viscosity of
the resin composition based on the plasticizing effect of the organic
phosphorus compound also has the effect of reducing the wearability of
the surface of a mold.
[0076] The organic phosphorus compound-based flame retardant as the
component D of the present invention especially is at least one phosphate
represented by the following general formula (1): 1
[0077] wherein X is a divalent group derived from hydroquinone,
resorcinol, bis(4-hydroxydiphenyl)methane, bisphenol A,
dihydroxydiphenyl, dihydroxynaphthalene, bis(4-hydroxyphenyl)sulfone,
bis(4-hydroxyphenyl)ketone or bis(4-hydroxyphenyl)sulfide, j, k, 1 and m
are each independently 0 or 1, n is an integer of 0 to 5 or an average
value of 0 to 5 in the case of a mixture of an n number of different
phosphates, and R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are each
independently a monovalent group derived from phenol, cresol, xylenol,
isopropylphenol, butylphenol or p-cumylphenol which is substituted or not
substituted by one or more halogen atoms.
[0078] More preferred is an organic phosphorus compound-based flame
retardant of the above formula in which X is a divalent group derived
from hydroquinone, resorcinol, bisphenol A or dihydroxydiphenyl, j, k, l
and m are each 1, n is an integer of 1 to 3 or an average value of 1 to 3
in the case of a blend of an n number of phosphates, and R.sup.1,
R.sup.2, R.sup.3 and R.sup.4 are each independently a monovalent group
derived from phenol, cresol or xylenol which is substituted by one or
more halogen atoms, preferably not substituted.
[0079] The organic phosphorus compound as the component D has a TGA 5%
weight reduction temperature of 280.degree. C. or higher when it is
heated up to 600.degree. C. from 23.degree. C. at a temperature elevation
rate of 20.degree. C./minute in a nitrogen gas atmosphere. The weight
reduction temperature is preferably 320.degree. C. or higher, more
preferably 330.degree. C. or higher, particularly preferably 340.degree.
C. or higher. The upper limit of the weight reduction temperature is
suitably 380.degree. C. because an organic phosphorus compound having
this upper limit can be generally acquired, more suitably 370.degree. C.
An organic phosphorus compound having a relatively high weight reduction
temperature is preferred because it can provide excellent heat resistance
(excellent load deflection temperature) to the resin composition together
with the effect of reducing the melt viscosity of the resin composition.
[0080] Taking the above points into consideration, a phosphate oligomer
comprising resorcinol bis(dixylenylphosphate) as the main component,
phosphate oligomer comprising 4,4-dihydroxydiphenyl
bis(dixylenylphosphate) as the main component and phosphate oligomer
comprising bisphenol A bis(diphenylphosphate) as the main component are
preferred (the expression "main component" means that other components
having a different degree of polymerization may be contained in small
amounts) out of the phosphates of the above formula.
[0081] The resin composition of the present invention comprises a
fluorine-containing anti-dripping agent (component E). Excellent flame
retardancy can be attained by containing this fluorine-containing
anti-dripping agent (component E) without impairing the physical
properties of a molded article.
[0082] The fluorine-containing anti-dripping agent as the component E is a
fluorine-containing polymer having fibril forming capability. Examples of
the polymer include polytetrafluoroethylene, tetrafluoroethylene-based
copolymers (such as tetrafluoroethylene/hexafluoropropylene copolymer),
partially fluorinated polymers as disclosed by U.S. Pat. No. 4,379,910
and polycarbonate resins produced from a fluorinated diphenol. Out of
these, polytetrafluoroethylene (may be abbreviated as PTFE hereinafter)
is particularly preferred.
[0083] PTFE having fibril forming capability has an extremely high
molecular weight and shows a tendency to become fibrous through
combination with another PTFE by an external function such as shear
force. The molecular weight of PTFE is 1,000,000 to 10,000,000, more
preferably 2,000,000 to 9,000,000 in terms of number average molecular
weight obtained from standard specific gravity. PTFE may be used in a
solid form or aqueous dispersion form. A mixture of PTFE having fibril
forming capability and another resin may be used to improve
dispersibility in a resin and obtain more excellent flame retardancy and
mechanical properties.
[0084] Commercially available products of PTFE having fibril forming
capability include Teflon 6J of Mitsui.cndot.Du Pont Fluorochemical Co.,
Ltd., and Polyflon MPA FA-500 and F-201L of Daikin Industries, Ltd.
Commercially available products of the aqueous dispersion of PTFE include
Fluon AD-1 and AD-936 of Asahi ICI Fluoropolymers Co., Ltd., Fluon D-1
and D-2 of Daikin Industries, Ltd., and Teflon 30J of Mitsui.cndot.Du
Pont Fluorochemical Co., Ltd.
[0085] A PTFE mixture may be obtained by (1) a method in which an aqueous
dispersion of PTFE and an aqueous dispersion or solution of an organic
polymer are mixed together to carry out co-precipitation so as to obtain
a co-agglomerated mixture (JP-A 60-258263 and JP-A 63-154744), (2) a
method in which an aqueous dispersion of PTFE and dried organic polymer
particles are mixed together (method disclosed by JP-A 4-272957), (3) a
method in which an aqueous dispersion of PTFE and an organic polymer
particle solution are uniformly mixed together and media are removed from
the mixture at the same time (JP-A 06-220210 and JP-A08-188653), (4) a
method in which a monomer for forming an organic polymer is polymerized
in an aqueous dispersion of PTFE (method disclosed by JP-A 9-95583) or
(5) a method in which an aqueous dispersion of PTFE and an organic
polymer dispersion are uniformly mixed together and then a vinyl-based
monomer is polymerized in the dispersion mixture to obtain a mixture
(method disclosed by JP-A 11-29679). Commercially available products of
the PTFE mixture include Metablen A3000 (trade name) of Mitsubishi Rayon
Co., Ltd. and BLENDEX B449 (trade name) of GE Specialty Chemicals Co.,
Ltd.
[0086] The amount of PTFE in the mixture is preferably 1 to 60 wt %, more
preferably 5 to 55 wt % based on 100 wt % of the PTFE mixture. When the
amount of PTFE is within the above range, the excellent dispersibility of
PTFE can be attained. The amount of the component E shows the net
quantity of the fluorine-containing anti-dripping agent or the net
quantity of PTFE in the case of the PTFE mixture.
[0087] Preferably, the resin composition of the present invention further
comprises an ester (component F) of a monohydric or polyhydric alcohol
and a higher fatty acid as an optional component. A resin composition
having excellent releasability while maintaining the above effect of the
present invention can be provided by using the component F. As a result,
there is provided a molded article having excellent dimensional
stability. Particularly when a more preferred component D is contained in
the present invention, the preferred effect of the component F is
exhibited. The more preferred component D is as described above.
[0088] The higher fatty acid forming the ester as the component F contains
60 wt % or more of a fatty acid having preferably 20 or more carbon atoms
(more preferably 20 to 32 carbon atoms, much more preferably 26 to 32
carbon atoms). The higher fatty acid is preferably a higher fatty acid
comprising montanic acid as the main component. The higher fatty acid is
generally produced by oxidizing montan wax.
[0089] Examples of the monohydric alcohol forming the component F include
dodecanol, tetradecanol, hexadecanol, octadecanol, eicosanol,
tetracosanol, ceryl alcohol and triacontanol.
[0090] Examples of the polyhydric alcohol forming the component F include
ethylene glycol, glycerin, diglycerin, polyglycerin (such as
decaglycerin), pentaerythritol, dipentaerythritol, trimethylolpropane,
diethylene glycol and propylene glycol. Out of these, ethylene glycol,
glycerin, pentaerythritol, dipentaerythritol and trimethylolpropane are
preferred, and ethylene glycol is particularly preferred.
[0091] Preferably, the ester of a higher fatty acid comprising montanic
acid as the main component and a monohydric or polyhydric alcohol
(preferably polyhydric alcohol) has a density of 0.94 to 1.10 g/cm.sup.3,
an acid value of 1 to 200 and a saponification value of 50 to 200. More
preferably, the ester has a density of 0.98 to 1.06 g/cm.sup.3, an acid
value of 5 to 30 and a saponification value of 100 to 180.
[0092] A description is subsequently given of the amounts of the
components A to E and the component F as an optional component forming
the resin composition of the present invention.
[0093] In the resin composition of the present invention, the total amount
of the aromatic polycarbonate resin (component A) and the
acrylonitrile-styrene copolymer (component B; AS resin) as the resin
components is 60 wt % or more, preferably 60 wt % or more based on 100 wt
% of the total of the components A, B, C and D. The upper limit of the
total amount of the components A and B which is mainly influenced by the
amounts of the components C and D is 80 wt %, preferably 76 wt %.
[0094] As for the ratio of the components A and B, the amount of the
component A is 75 to 95 parts by weight and the amount of the component B
is 5 to 25 parts by weight based on 100 parts by weight of the total of
the components A and B. Preferably, the amount of the component A is 78
to 92 parts by weight and the amount of the component B is 8 to 22 parts
by weight.
[0095] The amount of the inorganic fillers (components C) as the total
amount of the components C-1 and C-2 is 15 to 35 wt %, preferably 20 to
30 wt % based on 100 wt % of the total of the components A to D. The
amount of the component C-1 is 10 to 25 wt %, preferably 10 to 20 wt %,
particularly preferably 12 to 20 wt % and the amount of the component C-2
is 3 to 15 wt %, preferably 5 to 15 wt %, particularly preferably 5 to 12
wt % based on 100 wt % of the total of the components A to D. As for the
ratio of the components C-1 and C-2, the amount of the component C-1 is
40 to 90 parts by weight and the amount of the component C-2 is 60 to 10
parts by weight based on 100 parts by weight of the total of the
components C-1 and C-2. Preferably, the amount of the component C-1 is 50
to 80 parts by weight and the amount of the component C-2 is 50 to 20
parts by weight.
[0096] The amount of the organic phosphorus compound (component D) as a
flame retardant is 3 to 15 wt %, preferably 3 to 10 wt %, more preferably
3 to 6 wt % based on 100 wt % of the total of the components A to D.
[0097] The amount of the fluorine-containing anti-dripping agent
(component E) is 0.02 to. 2 parts by weight, preferably 0.05 to 2 parts
by weight, more preferably 0.1 to 1 part by weight, particularly
preferably 0.15 to 0.8 part by weight based on 0.100 parts by weight of
the total of the components A to D. The amount of the higher fatty acid
ester (component F) as a release agent is 2 parts or less by weight,
preferably 0.01 to 2 parts by weight, more preferably 0.05 to 1.5 parts
by weight, particularly preferably 0.1 to 1.0 part by weight based on 100
parts by weight of the total of the components A to D.
[0098] When the resin composition of the present invention has the above
composition, a molded article obtained from the composition has excellent
physical properties and excellent flame retardancy. That is, the molded
article has an impact strength (J/m) of 30 or more, preferably 35 or
more, and its upper limit preferably reaches 55. The shrinkage anisotropy
of the molded article (absolute value of a difference in molding
shrinkage factor (%) between the flow direction and a direction
perpendicular to that direction of the molded article) is small at 0.15
or less, preferably 0.10 or less.
[0099] The molded article obtained from the resin composition of the
present invention can attain V-1 rating in a UL94 flame retardancy test
of a 1.6-thick test specimen although it has a relatively small content
of the flame retardant (component D).
[0100] The present invention provides a molded article having high
stiffness and low specific gravity due to a combination of the component
B, the components C-1 and C-2 as inorganic fillers and the component D.
The specific gravity is 1.3 to 1.45 (g/cm.sup.3), or 1.32 to 1.40
(g/cm.sup.3) under favorable conditions in terms of true density.
[0101] Molded articles obtained from the resin composition comprising the
components A to E and the resin composition comprising the components A
to F of the present invention have excellent resistance to low-viscosity
lubricating oil. A chassis molded product may be coated with lubricating
oil in advance or may be coated with lubricating oil while it is in use
so that constituent parts which will be assembled with the chassis molded
product can function smoothly. Therefore, the above excellent resistance
is a preferred property required for the chassis molded product.
[0102] Examples of the low-viscosity lubricating oil include hydrocarbon
oil, silicone oil and fluorine oil. The molded articles obtained from the
resin composition comprising the components A to E and the resin
composition comprising the components A to F of the present invention
have excellent resistance to hydrocarbon oil which is widely used out of
these lubricating oils, particularly to lubricating oil containing
paraffin oil as the main component which is the most frequently used.
[0103] The above low-viscosity lubricating oil has a kinematic viscosity
at 40.degree. C. of 2 to 20 mm.sup.2/s, preferably 2 to 10 mm.sup.2/s.
Specific examples of the low-viscosity lubricating oil include the
CRC5-56 of KURE Engineering Ltd.
[0104] The resin composition of the present invention has an advantage
that the wearability of a mold is very low due to use of a combination of
the components C-1 and C-2 as inorganic fillers (components C), thereby
making it possible to reduce molding cost.
[0105] The resin composition of the present invention may contain other
components if they do not impair the object of the present invention and
the amounts of the components A to F are maintained. Thermoplastic resins
other than the components A and B include polyethylene resin,
polypropylene resin, polyalkyl methacrylate resin, polyacetal resin,
polyalkylene terephthalate resin, polyamide resin, cyclic polyolefin
resin, polyarylate resin (noncrystalline polyarylate, liquid crystal
polyarylate), polyether ether ketone, thermoplastic polyimides typified
by polyether imide and polyamide-imide, polysulfone, polyether sulfone
and polyphenylene sulfide. They may be used in combination with the
component A and the component B according to purpose. Particularly when
vibration damping properties are required, a polyarylate resin is
preferably used in combination because both excellent flame retardancy
and vibration damping properties can be obtained.
[0106] The flame retardant resin composition of the present invention may
further contain a small amount of a rubber-like polymer. The amount of
the rubber-like polymer is suitably 1.5 parts or less by weight,
preferably 1.3 parts or less by weight, more preferably 1 part or less by
weight based on 100 parts by weight of the total of the components A to
D.
[0107] Specific examples of the rubber-like polymer include SB
(styrene-butadiene) polymer, ABS (acrylonitrile-butadiene-styrene)
polymer, MBS (methyl methacrylate-butadiene-styrene) polymer, MABS
(methyl methacrylate-acrylonitrile-butadiene-styrene) polymer, MB (methyl
methacrylate-butadiene) polymer, ASA (acrylonitrile-styrene-acrylic
rubber) polymer, AES (acrylonitrile-ethylene propylene rubber-styrene)
polymer, MA (methyl methacrylate-acrylic rubber) polymer, MAS (methyl
methacrylate-acrylic rubber-styrene) polymer, methyl
methacrylate-acryl.butadiene rubber copolymer, methyl
methacrylate-acryl.butadiene-styrene copolymer and methyl
methacrylate-(acryl.silicone IPN rubber) polymer. These polymers are
preferably core-shell type graft copolymers in which a polymer chain
composed of the above monomer is bonded to a core made from a polymer
comprising a rubber component.
[0108] The rubber-like polymer of the present invention may be contained
in another component. This rubber-like polymer is, for example, an ABS
copolymer contained in ABS resin.
[0109] Flame retardants other than the organic phosphorus compound as the
component D of the present invention include red phosphorus-based flame
retardants, halogen compound-based flame retardants, silicone-based flame
retardants and metal salt-based flame retardants. However, in the present
invention, what contains only the component D as a flame retardant is
preferred.
[0110] In the present invention, a small amount of an inorganic filler
other than the components C-1 and C-2 may be contained in limits that do
not impair the object of the present invention. A glass-based filler
(Mohs hardness of about 6.5) such as glass fiber or glass flake, aluminum
borate whisker (Mohs hardness of about 7), titanium oxide (Mohs hardness
of about 7 for a rutile type) or other high-hardness filler is suitably
contained in an amount of 3 parts or less by weight, preferably 1 part or
less by weight based on 100 parts by weight of the total of the
components A to D. When a filler having a Mohs hardness of 5 or less is
used, it may be contained in an amount of more than 3 parts by weight,
preferably 5 parts or less by weight.
[0111] A heat stabilizer, antioxidant, ultraviolet light absorber, release
agent (other than the component F), antistatic agent, blowing agent, dye
and pigment (especially carbon black, titanium oxide or the like) may be
mixed with the resin composition of the present invention.
[0112] The heat stabilizer is a phosphorus-based heat stabilizer such as
phosphorous acid, phosphoric acid, phosphonous acid, phosphonic acid or
ester thereof. Examples of the heat stabilizer include phosphite
compounds such as triphenyl phosphate, trisnonylphenyl phosphate,
tris(2,4-di-tert-butylphenyl)phosphite, tridecylphosphite, trioctyl
phosphate, trioctadecyl phosphate, didecylmonophenyl phosphite,
dioctylmonophenyl phosphate, diisopropylmonophenol phosphite,
monobutyldiphenyl phosphate, monodecyldiphenyl phosphate,
monooctyldiphenyl phosphate, bis(2,6-di-tert-butyl-4-methylphenyl)pentaer-
ythritol diphosphite, 2,2-methylenebis(4,6-di-tert-butylphenyl)octyl
phosphate, bis(nonylphenyl)pentaerythritol diphosphite and
bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite, phosphate
compounds such as tributyl phosphate, trimethyl phosphate, tricresyl
phosphate, triphenyl phosphate, trichlorophenyl phosphate, triethyl
phosphate, diphenylcresyl phosphate, diphenylmonoorthoxenyl phosphate,
tributoxyethyl phosphate, dibutyl phosphate, dioctyl phosphate and
diisopropyl phosphate, and phosphonite compounds as other
phosphorus-based heat stabilizers, such as tetrakis(2,4-di-tert-butylphen-
yl)-4,4'-biphenylene diphosphonite, tetrakis(2,4-di-tert-butylphenyl)-4,3'-
-biphenylene diphosphonite, tetrakis(2,4-di-tert-butylphenyl)-3,3'-bipheny-
lene diphosphonite and bis(2,4-di-tert-butylphenyl)-4-biphenylene
phosphonite. Out of these, preferred are trisnonylphenyl phosphate,
distearylpentaerythritol diphosphite, bis(2,4-di-tert-butylphenyl)pentaer-
ythritol diphosphite, tris(2,4-di-tert-butylphenyl)phosphite, triphenyl
phosphate, trimethyl phosphate, tetrakis(2,4-di-tert-butylphenyl)-4,4'-bi-
phenylene diphosphonite and bis(2,4-di-tert-butylphenyl)-4-biphenylene
phosphonite. These heat stabilizers may be used alone or in combination
of two or more. The amount of the heat stabilizer is preferably 0.0001 to
1 part by weight, more preferably 0.0005 to 0.5 part by weight, much more
preferably 0.002 to 0.3 part by weight based on 100 parts by weight of
the total of the components A to D.
[0113] Examples of the antioxidant include pentaerythritol
tetrakis(3-mercaptopropionate), pentaerythritol tetrakis(3-laurylthioprop-
ionate), glycerol-3-stearylthiopropionate, triethylene
glycol-bis([3-(3-t-butyl-5-methyl-4-hydroxyphenyl)propionate],
1,6-hexanediol-bis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate],
pentaerythritol-tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate],
octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate,
1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene,
N,N-hexamethylenebis(3,5-di-t-butyl-4-hydroxy-hydrocinnamide),
3,5-di-t-butyl-4-hydroxy-benzyl phosphonate-diethyl ester,
tris(3,5-di-t-butyl-4-hydroxybenzyl)isocyanurate, tetrakis(2,4-di-t-butyl-
phenyl)-4,4'-biphenylene diphosphinate and 3,9-bis{1,1-dimethyl-2-[.beta.--
(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy]ethyl}-2,4,8,10-tetraoxas-
piro(5,5)undecane. The amount of the antioxidant is preferably 0.0001 to
0.05 part by weight based on 100 parts by weight of the total of the
components A to D.
[0114] Examples of the ultraviolet light absorber include
benzophenone-based ultraviolet light absorbers typified by
2,2'-dihydroxy-4-methoxybenzophenone, and benzotriazole-based ultraviolet
light absorbers typified by 2-(3-tert-butyl-5-methyl-2-hydroxyphenyl)-5-c-
hlorobenzotriazole, 2-(3,5-di-tert-butyl-2-hydroxyphenyl)-5-chlorobenzotri-
azole, 2,2'-methylenebis[4-(1,1,3,3-tetramethylbutyl)-6-(2H-benzotriazol-2-
-yl)phenol], 2-[2-hydroxy-3,5-bis(.alpha.,.alpha.-dimethylbenzyl)phenyl]-2-
H-benzotriazole and 2-(3,5-di-tert-amyl-2-hydroxyphenyl)benzotriazole.
Further, a hindered amine-based optical stabilizer typified by
bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate and bis(1,2,2,6,6-pentamethy-
l-4-piperidyl)sebacate may also be used. The total amount of the
ultraviolet light absorber and optical stabilizer is preferably 0.01 to 5
parts by weight based on 100 parts by weight of the total of the
components A to D.
[0115] As a release agent other than the component F may be used an
olefin-based wax, silicone oil, fluorine oil, organopolysiloxane,
paraffin wax or beeswax.
[0116] Examples of the antistatic agent include polyether ester amide,
glycerin monostearate, ammonium salts and phosphonium salts of
dodecylbenzene sulfonic acid, maleic anhydride monoglyceride and maleic
anhydride diglyceride. The amount of the antistatic agent is preferably
0.5 to 20 parts by weight based on 100 parts by weight of the total of
the components A to D.
[0117] When the inventor of the present invention conducted further
studies, he found that the above advantage and effect of the resin
composition are attained by a resin composition which comprises
polyphenylene ether resin and polystyrene resin as resin components as
well.
[0118] According to the present invention, there is provided a flame
retardant aromatic polyphenylene ether resin composition (to be referred
to as "PPE resin composition" hereinafter) comprising (1) a polyphenylene
ether resin (component P), (2) a polystyrene resin (component S), (3)
inorganic fillers (components C), (4) an organic phosphorus
compound-based flame retardant (component D) and (5) a
fluorine-containing anti-dripping agent (component E), the amounts of
these components satisfying the following conditions (i) to (iii).
[0119] (i) The total amount of the components P and S is 50 wt % or more,
the amount of the component C is 15 to 35 wt %, and the amount of the
component D is 3 to 15 wt % based on 100 wt % of the total of the
components P, S, C and D, and the amount of the component E is 0 to 2
parts by weight based on 100 parts by weight of the total of the
components P, S, C and D;
[0120] (ii) the amount of the component P is 50 to 85 parts by weight and
the amount of the component S is 15 to 50 parts by weight based on 100
parts by weight of the total of the components P and S; and
[0121] (iii) the components C consist of (C1) mica having an average
particle diameter of 30 to 300 .mu.m (component C-1) and (C2) at least
one filler (component C-2) selected from the group consisting of talc and
wollastonite, the amount of the component C-1 is 10 to 25 wt % and the
amount of the component C-2 is 3 to 15 wt % based on 100 wt % of the
total of the components P, S, C and D, and the amount of the component
C-1 is 40 to 90 parts by weight based on 100 parts by weight of the total
of the components C-1 and C-2.
[0122] The polyphenylene ether resin (component P) in this PPE resin
composition is a polymer or copolymer of a nucleus-substituted phenol
having a phenylene ether structure (may be simply referred to as "PPE
polymer" hereinafter).
[0123] Typical examples of the polymer of a nucleus-substituted phenol
having a phenylene ether structure include poly(2,6-dimethyl-1,4-phenylen-
e)ether, poly(2-methyl-6-ethyl-1,4-phenylene)ether,
poly(2,6-diethyl-1,4-phenylene)ether, poly(2-ethyl-6-n-propyl-1,4-phenyle-
ne)ether, poly(2,6-di-n-propyl-1,4-phenylene)ether,
poly(2-methyl-6-n-butyl-1,4-phenylene)ether, poly(2-ethyl-6-isopropyl-1,4-
-phenylene)ether, poly(2-methyl-6-hydroxyethyl-1,4-phenylene)ether and
poly(2-methyl-6-chloroethyl-1,4-phenylene)ether. Out of these,
poly(2,6-dimethyl-1,4-phenylene)ether is particularly preferred.
[0124] Typical examples of the copolymer of a nucleus-substituted phenol
having a phenylene ether structure include a copolymer of
2,6-dimethylphenol and 2,3,6-trimethylphenol, a copolymer of
2,6-dimethylphenol and o-cresol, and a copolymer of 2,6-dimethylphenol,
2,3,6-trimethylphenol and o-cresol.
[0125] The method of producing the above PPE polymer is not particularly
limited but the PPE polymer can be produced by the oxidation coupling
polymerization of 2,6-xylenol in the presence of dibutylamine in
accordance with the method disclosed by U.S. Pat. No. 4,788,277 (Japanese
Patent Application No. 62-77570).
[0126] PPE polymers having different molecular weights and molecular
weight distributions may be used. As for the molecular weight, the
reduced viscosity measured in a 0.5 g/dl chloroform solution at
30.degree. C. of the PPE polymer is in the range of preferably 0.20 to
0.70 dl/g, more preferably 0.30 to 0.55 dl/g.
[0127] The PPE polymer may contain a phenylene ether unit which has been
proposed to be contained in a polyphenylene ether resin as a partial
structure as far as it is not against the subject matter of the present
invention. Examples of the phenylene ether unit which is proposed to be
contained in a small amount include 2-(dialkylaminomethyl)-6-methylphenyl-
ene ether unit and 2-(N-alkyl-N-phenylaminomethyl)-6-methylphenylene ether
unit as disclosed by Japanese Patent Application No. 63-12698 and
Japanese Patent Application No. 63-301222. A PPE polymer containing a
small amount of diphenoquinone bonded to the main chain may also be used.
[0128] In the PPE resin composition of the present invention, a
polystyrene resin (component S) is used as a resin component other than
the component P. Preferably, the polystyrene resin (component S)
comprises styrene as a monomer unit forming the styrene resin in an
amount of 85 wt % or more, preferably 90 wt % or more. A generally called
polystyrene resin is used. For example, HIPS (high impact polystyrene) is
also preferably used.
[0129] The PPE resin composition of the present invention comprises
inorganic fillers (components C), an organic phosphorus compound-based
flame retardant (component D) and a fluorine-containing anti-dripping
agent (component E) as an optional component in addition to the resin
components P and S. Since examples of the components C, D and E are the
same as those of the above resin composition, their descriptions are
omitted for the PPE resin composition. The compounds enumerated above are
used as the components C, D and E, and preferred examples are the same as
those of the components C, D and E.
[0130] The amount of each component of the PPE resin composition of the
present invention is described hereinbelow.
[0131] The total amount of the polyphenylene ether resin (component P) and
the polystyrene resin (component S) as resin components is 50 wt % or
more, preferably 60 wt % or more based on 100 wt % of the total of the
components P, S, C and D, and the upper limit of the total amount of the
components P and S which changes according to the amounts of the
components C and D is 82 wt %, preferably 75 wt %. As for the ratio of
the components P and S, the amount of the component P is 50 to 85 parts
by weight and the amount of the component S is 15 to 50 parts by weight
based on 100 parts by weight of the total of the components P and S.
Preferably, the amount of the component P is 55 to 75 parts by weight and
the amount of the component S is 25 to 45 parts by weight based on 100
parts by weight of the total of the components P and S.
[0132] The total amount of the inorganic fillers (components C) is 15 to
35 wt %, preferably 20 to 30 wt % as the total of the components C-1 and
C-2 based on 100 wt % of the total of the components P, S, C and D. The
amount of the component C-1 is 10 to 25 wt %, preferably 10 to 20 wt %,
particularly preferably 12 to 20 wt % and the amount of the component C-2
is 3 to 15 wt %, preferably 5 to 15 wt %., particularly preferably 5 to
12 wt % based on 100 wt % of the total of the components P, S, C and D.
As for the ratio of the components C-1 and C-2, the amount of the
component C-1 is 40 to 90 parts by weight and the amount of the component
C-2 is 60 to 10 parts by weight, preferably the amount of the component
C-1 is 50 to 80 parts by weight and the amount of the component C-2 is 50
to 20 parts by weight based on 100 parts by weight of the total of the
components C-1 and C-2.
[0133] The amount of the organic phosphorus compound (component D) as a
flame retardant is 3 to 15 wt %, preferably 5 to 12 wt % based on 100 wt
% of the total of the components P, S, C and D.
[0134] The amount of the fluorine-containing anti-dripping agent
(component E) is 2 parts or less by weight, preferably 0.05 to 2 parts by
weight, particularly preferably 0.1 to 1 part by weight based on 100
parts by weight of the total of the components P, S and D. A higher fatty
acid ester (component F) may be used as a release agent. The amount of
the component F is 2 parts or less by weight, preferably 0.01 to 2 parts
by weight, particularly preferably 0.05 to 1 part by weight based on 100
parts by weight of the total of the components P, S, C and D.
[0135] The flame retardant resin composition (including the PPE resin
composition) of the present invention can be produced by mixing together
the above components by a mixer such as a tumbler, twin-cylinder mixer,
Nauter mixer, Banbury mixer, kneading roll or extruder at the same time
or in an arbitrary order. Preferably, they are melt kneaded together by a
twin-screw extruder and the components C are supplied from a second
supply port by a side feeder or the like to be mixed with other
components which have been melt mixed together. The thus obtained
composition can be easily formed by an existing technique such as
injection molding, extrusion molding, compression molding or rotational
molding. A high-accuracy chassis for precision instruments can be formed
by injection molding. Injection compression molding and molding with a
heat insulating mold can be used in combination to attain higher
accuracy, or gas assist molding can be used in combination to reduce
weight and distortion.
[0136] According to the present invention, there is provided a flame
retardant resin composition having excellent stiffness, dimensional
accuracy and strength and low mold wearability. There are further
provided chassis and frames molded articles from the above resin
composition. The flame retardant thermoplastic resin composition of the
present invention is particularly suitable for use in chassis and frames
for OA-related equipment incorporating a precision part such as an
optical unit. The OA-related equipment include printers (especially laser
beam printers), copying machines, facsimiles and projectors. The resin
composition of the present invention is also suitable for use in chassis
and frames for robots for domestic use incorporating precision sensors.
BRIEF DESCRIPTION OF THE DRAWINGS
[0137] FIG. 1 [1-A] is a front view showing the shape of a plate-like
molded article for the evaluation of mold wearability used in Examples. A
pin portion arranged near a gate forms a conical depression.
[0138] [1-B] is a side view showing the shape of the plate-like molded
article for the evaluation of mold wearability used in Examples.
[0139] [1-C] is a bottom view showing the shape of the plate-like molded
article for the evaluation of mold wearability used in Examples.
[0140] FIG. 2 is a front view showing the shape of a pin for the
evaluation of mold wearability used in Examples. A conical end portion is
exposed to the surface of a mold cavity and contacts a molten resin.
[0141] FIG. 3 [3-A] is a front view showing the shape of a cup-like molded
article for the evaluation of release force used in Examples.
[0142] [3-B] is a side view showing the shape of the cup-like molded
article for the evaluation of release force used in Examples.
[0143] [3-C] is a bottom view showing the shape of the cup-like molded
article for the evaluation of release force.
[0144] FIG. 4 [4-A] schematically shows a mold structure used for the
evaluation of release force. A mold cavity is filled with a resin.
[0145] [4-B] shows that the mold is cooled and opened after filling in
[4-A]. At this point, a molded article is adhered to a movable mold.
[0146] [4-C] shows that an ejector pin is forced out by the advance of an
ejector rod after the opening of the mold in
[0147] [4-B] to remove the molded article. Ejection force is detected by a
load cell in contact with the ejector pin.
[0148] FIG. 5 is a perspective view showing the outline of a jig for
3-point bending in the evaluation of the low-viscosity lubricating oil
resistance of a molded article which is one of the evaluation items in
the above Examples.
EXPLANATION OF REFERENCE NUMERALS
[0149] 1 plate-like molded article for the evaluation of mold wearability
[0150] 2 conical depression formed by a pin
[0151] 3 gate (4 mm in width, 1.5 mm in thickness)
[0152] 4 length of the plate-like molded article for the evaluation of
mold wearability (100 mm)
[0153] 5 distance from the gate portion to the pin (10 mm)
[0154] 6 diameter of the conical depression formed by the pin (pin
diameter) (10 mm)
[0155] 7 center line (center of the pin is existent on the center line of
the molded article)
[0156] 8 depth of the conical depression formed by the pin (pin height) (3
mm)
[0157] 9 thickness of the plate-like molded article for the evaluation of
mold wearability (5 mm)
[0158] 10 width of the plate-like molded article for the evaluation of
mold wearability (50 mm)
[0159] 11 pin diameter (10 mm)
[0160] 12 height of the conical portion (portion exposed to the surface of
the mold cavity) of the pin (3 mm)
[0161] 21 cup-like molded article body
[0162] 22 distance from the axis of symmetry (26) of a grip portion (15
mm)
[0163] 23 grip portion
[0164] 24 height of the grip portion (20 mm)
[0165] 25 top end face of the cup (radius of the corner portion: 2.5 mm)
[0166] 26 axis of symmetry
[0167] 27 inner bottom hole (radius of 1 mm)
[0168] 28 Z pin projection (radius from the center axis to the periphery
of 7.5 mm)
[0169] 29 inner bottom portion of the cup (radius of the corner portion: 5
mm)
[0170] 30 thickness of the grip portion (4 mm)
[0171] 31 distance from the center axis (34) to the center axis of the
inner bottom hole (27) (13 mm)
[0172] 32 distance from the center axis (34) to the periphery of the
bottom face (36) of the cup (26 mm)
[0173] 33 distance from the center axis (34) to the periphery of the top
end face (25) of the cup (30 mm)
[0174] 34 center axis of the cup
[0175] 35 sprue (outer radius: 6 mm, radius of end portion: 3 mm, length:
39 mm)
[0176] 36 bottom face of the cup
[0177] 37 thickness of the bottom portion of the cup (4 mm)
[0178] 38 the thickness of the peripheral portion of the cup (2.5 mm, the
same along the entire periphery)
[0179] 39 outer wall of the cup
[0180] 41 fixed mold
[0181] 42 molded article
[0182] 43 ejector pin (Z pin at the end)
[0183] 44 load cell
[0184] 51 first fixing rod (made from stainless steel and having a
diameter of 3.9 mm)
[0185] 52 center portion of a test specimen (placed such that it is
positioned at the top of an arc drawn by the test specimen and a gauze
impregnated with lubricating oil is placed on that portion)
[0186] 53 moving rod for applying distortion (made from stainless steel
and having a diameter of 3.9 mm)
[0187] 54 screw for applying distortion (screwed to the rear side of a
base 57, turned from a position where it contacts the test specimen under
no load to apply a predetermined amount of distortion to the test
specimen based on a screw pitch)
[0188] 55 test specimen (shape in accordance with ASTM D638 Type I)
[0189] 56 second fixing rod (made from stainless steel and having a
diameter of 3.9 mm)
[0190] 57 base
[0191] 58 horizontal distance from the second fixing rod to the moving rod
for applying distortion (50.0 mm)
[0192] 59 horizontal distance from the first fixing rod to the moving rod
for applying distortion (50.0 mm)
EXAMPLES
[0193] The following examples are provided to further illustrate the
present invention.
Examples 1 to 11 and Comparative Examples 1 to 6
[0194] Components A, B, D, P, S and other components shown in Tables 1 to
6 excluding inorganic fillers (components C-1 and C-2 and an inorganic
filler other than the present invention) were mixed together by a
twin-cylinder mixer to prepare a mixture. After a pre-mixture of
component E and 2.5 wt % of the component A (PC) or P (PPE) was prepared
by placing them in a polyethylene bag and stirring manually, it was mixed
with the other components. The mixture obtained by mixing by the
twin-cylinder mixer was supplied from a first supplying port in the
rear-end portion (a predetermined amount of the component D in Examples 4
and 11 was heated at 80.degree. C. and supplied into an extruder by a
quantitative liquid transfer unit) and inorganic fillers (components C-1
and C-2 and an inorganic filler other than the present invention) were
supplied from a second supply port in a cylinder by a side feeder in a
predetermined ratio by using a meter and melt extruded at a cylinder
temperature of 270.degree. C. in a vacuum of 3 kPa by using a vented
twin-screw extruder having a screw diameter of 30 mm (TEX-30.times.SST of
Japan Steel Works, Ltd.) and a vacuum pump to be pelletized. The obtained
pellet was dried at 100.degree. C. by a hot air circulation drier for 6
hours to form a test specimen for evaluation at a cylinder temperature of
260.degree. C. and a mold temperature of 70.degree. C. by an injection
molding machine (SG-150U of Sumitomo Heavy Industries, Ltd.) so as to
carry out evaluations in accordance with the following methods unless
otherwise stated in the following evaluation items.
[0195] (1) Mechanical Properties of Flame Retardant Resin Composition
[0196] (i) stiffness: flexural modulus was measured in accordance with
ASTM D-790 (size of test specimen: 127 mm (length).times.12.7 mm
(width).times.6.4 mm (thickness))
[0197] (ii) impact resistance: Izod notched impact was measured in
accordance with ASTM D-256 (A method: thickness of test specimen: 3.2 mm)
[0198] (iii) true density: measured in accordance with ASTM D-792
(23.degree. C.)
[0199] (iv) heat resistance: Distortion temperature under load was
measured under a load of 1.82 MPa in accordance with ASTM D-648 (size of
test specimen: 127 mm (length).times.12.7 mm (width).times.6.4 mm
(thickness))
[0200] (v) flamability: A flaming test was carried out in accordance with
UL 94V.
[0201] (vi) molding shrinkage factor: After rectangular plates measuring
50 mm (width).times.100 mm (length).times.4 mm (thickness) were formed by
injection molding under the same conditions and left at 23.degree. C. and
a relative humidity of 50% for 24 hours, the sizes of the rectangular
plates were measured by a 3-D coordinate measuring machine (of Mitsutoyo
Corporation) to calculate their molding shrinkage factors. The above
rectangular plates were formed by using a mold cavity having a 50 mm wide
and 1.5 mm thick film gate at one end in the longitudinal direction.
Therefore, the longitudinal direction is a flow direction and the
transverse direction is a direction perpendicular to the flow direction.
Further, the molding conditions of the rectangular plates are as follows:
injection molding machine: SG-150U of Sumitomo Heavy Industries, Ltd,
cylinder temperature: 260.degree. C., mold temperature: 70.degree. C.,
filling time: 0.7 sec, dwell pressure: 61.6 MPa, dwell time: 15 sec.,
cooling time: 23 sec. Satisfactory molded articles were obtained under
the above conditions. Further, as for rectangular plates for size
evaluation, after 15 shots were continuously molded under the above
conditions, 10 shots were continuously molded and 5 specimens were
sampled from the molded products at random. The average value of the
specimens was taken as molding shrinkage factor.
[0202] (vii) Evaluation of mold wearability: 2,000 shots of the molded
product shown in FIG. 1 were molded, and the weight of the pin (made from
aluminum) was measured before and after molding to find a reduction in
the weight of the pin. The pin was cleaned with hexane, dried at
100.degree. C. with a hot air drier for 3 hours and left to be cooled in
a desiccator for 1 hour to measure its weight by an electronic balance.
To insert the pin into a mold, lubricating oil was applied to the pin
except a portion exposed to the surface of the cavity, and the pin was
cleaned with hexane, dried and left to be cooled again in the same manner
as described above after the molding test to measure its weight. The
evaluation was made as follows.
[0203] .circleincircle.: a weight reduction of 0.05 mg or less
[0204] .largecircle.: a weight reduction of more than 0.05 mg and 0.1 mg
or less
[0205] .DELTA.: a weight reduction of more than 0.1 mg and 0.2 mg or less
[0206] X: a weight reduction of more than 0.2 mg
[0207] (viii) measurement of release load
[0208] Release force required for removing the cup-like molded article
shown in FIG. 3 by ejecting the ejector pin was measured. The outline of
the mold used in this measurement is shown in FIG. 4. The measurement of
release force was carried out by placing a load cell (9800N) on an
ejector plate in such a manner that the distal end of the road cell is
contacted to the proximal end of the ejector pin to force out the ejector
pin. Force applied to the load cell at the time of ejection was measured
by the above means and the maximum value of the force was taken as
release force. 40 shots of the cup-like molded article were continuously
molded to stabilize release force and 20 shots were continuously molded
to measure the release force of each shot and take the average value of
the measurement data as release force in Tables 1 to 5. The molding
conditions of the cup-like molded article are as follows: injection
molding machine: T-series Model 150D of FANUC Ltd., cylinder temperature:
260.degree. C., mold temperature: 70.degree. C., filling time: 2.5 sec.,
dwell pressure: 58.8 MPa, dwell time: 5 sec., cooling time: 25 sec.
Satisfactory molded articles were obtained under the above conditions.
[0209] (ix) Evaluation of low-viscosity lubricating oil resistance
[0210] After 0.5% bending strain was applied to a 3.2 mm-thick test
specimen (tensile specimen TYPE-I) prepared in accordance with ASTM D-638
and low-viscosity lubricating oil (CRC5-56 of Kure Engineering Ltd.:
kinematic viscosity at 40.degree. C. of 4.2 mm.sup.2/s) was applied to
the test specimen and treated at 80.degree. C. for 72 hours, the
existence of a crack on the appearance of the molded article was observed
visually and the chemical resistance of the molded article was evaluated
based on the following criteria. How to mount the test specimen was shown
in FIG. 5.
[0211] .largecircle.: not cracked X: cracked
[0212] The bending strain (E=0.005) is calculated from the equation
.epsilon.=(6hy)/L.sup.2 when L is the span between two points at both
ends out of 3 points (100 mm), h is the thickness of the test specimen
(3.2 mm) and y is the height (mm) to which the test specimen is lifted
from the horizontal state.
[0213] (2) Composition of Flame Retardant Thermoplastic Resin Composition
[0214] The symbols in Tables 1 to 6 represent the following components.
[0215] (Component A)
[0216] PC-1: aromatic polycarbonate resin (aromatic polycarbonate resin
powder having a viscosity average molecular weight of 22,500 produced
from bisphenol A and phosgene in accordance with a commonly used method,
Panlite L-1225WP of Teiljin Chemicals, Ltd.)
[0217] PC-2: aromatic polycarbonate resin (aromatic polycarbonate resin
powder having a viscosity average molecular weight of 19,700 produced
from bisphenol A and phosgene in accordance with a commonly used method,
Panlite L-1225WX of Teiljin Chemicals, Ltd.)
[0218] (Component P)
[0219] PPE: polyphenylene ether resin (PPE of GEM Co., Ltd.)
[0220] (Component B)
[0221] AS-1: acrylonitrile-styrene copolymer (HP5670 of Cheil Industries,
Inc., weight average molecular weight in terms of standard polystyrene
measured by GPC: 95,000, acrylonitrile content: 28.5 wt %, styrene
content: 71.5 wt %)
[0222] AS-2: acrylonitrile-styrene copolymer (BS-218 of Nippon A & L Inc.,
weight average molecular weight in terms of standard polystyrene measured
by GPC: 78,000, acrylonitrile content: 26 wt %, styrene content: 74 wt %)
[0223] (Component S)
[0224] HIPS: polystyrene resin (Denka Styrol GP-1 of Denki Kagaku Kogyo
Kabushiki Kaisha)
[0225] (Component C-1)
[0226] MICA-1: muscovite having an average particle diameter of about 250
.mu.m (WHITE MICA POWDER 60 mesh of Ensei Kogyo Co., Ltd., Mohs hardness:
3)
[0227] MICA-2: muscovite having an average particle diameter of about 60
.mu.m (WHITE MICA POWDER 250 mesh of Ensei Kogyo Co., Ltd., Mohs
hardness: 3)
[0228] MICA-3: muscovite having an average particle diameter of about 40
.mu.m (Kuralite Mica 300D of Kuraray Co., Ltd., Mohs hardness: 3)
[0229] MICA-4: muscovite having an average particle diameter of about 40
.mu.m (MC-250 of Hayashi Kasei Co., Ltd., Mohs hardness: 3)
[0230] (Component C-2)
[0231] TALC-1: talc (Victorylite Talc R of Shokozan Mining Co., Ltd.,
particle diameter at an integration rate of 50%: 8.5 .mu.m, Hunter
whiteness measured in accordance with JIS M8016: 83.8%, pH: 9.6, Mohs
hardness: 1)
[0232] TALC-2: talc (Victorilite SG-A of Shokozan Mining Co., Ltd.,
particle diameter at an integration rate of 50%: 15.2 .mu.m, Hunter
whiteness measured in accordance with JIS M8016: 90.2%, pH: 9.8, Mohs
hardness: 1)
[0233] WSN: wollastonite (PH-450 of Kawatetsu Mining Company, Ltd., number
average fiber diameter: 1.6 .mu.m, number average fiber length: 6.7
.mu.m, Mohs hardness: 4.5)
[0234] (Inorganic Fillers Other than the Present Invention)
[0235] MICA-5: muscovite (A-41 of Yamaguchi Mica Co., Ltd., average
particle diameter: about 20 .mu.m)
[0236] GFL: granular glass flake (Fleka REFG-301 of Nippon Sheet Glass
Co., Ltd., median average diameter measured by standard screening method:
140 .mu.m, thickness: 5 .mu.m, Mohs hardness: 6.5)
[0237] (Component D)
[0238] FR-1: resorcinol bis(dixylenyl phosphate) (Adecastab FP-500 of
Asahi Denka Kogyo K.K., TGA 5% weight reduction temperature:
351.0.degree. C.)
[0239] FR-2: phosphate comprising bisphenol A bis(diphenyl phosphate) as
the main component (CR-741 of Daihachi Chemical Industry Co., Ltd., TGA
5% weight reduction temperature: 335.9.degree. C.)
[0240] FR-3: triphenyl phosphate (TPP of Daihachi Chemical Industry Co.,
Ltd., TGA 5% weight reduction temperature: 239.4.degree. C.)
[0241] (Component E)
[0242] PTFE: polytetrafluoroethylene having fibril forming capability
(Polyflon MPA FA500 of Daikin Industries, Ltd.)
[0243] (Component F)
[0244] WAX-1: montanate (WAX-E powder of Clariant Japan K.K.)
[0245] (Other Components)
[0246] WAX-2: acid modified polyolefin-based wax (Diacarna 30M of
Mitsubishi Chemical Corporation)
[0247] CB: carbon black master (polystyrene resin master containing 40% of
carbon black of Koshigaya Kasei Kogyo K.K.)
1 TABLE 1
Item Ex. 1 Ex. 2 Ex. 3 Ex. 4
Composition Component A (wt %) PC-1 61 61 61 59
Component B (wt %) AS-1 12 12 12 12
Component C (wt %) Component
C-1 MICA-1 15
MICA-2 15 15 15
Component C-2 TALC-1
7 7
TALC-2 7 7
Component D (wt %) FR-1 5 5 5
FR-2 7
Total of the components A to D: parts by weight 100
100 100 100
Component E (parts by weight) PTFE 0.3 0.3 0.3 0.3
Component F (parts by weight) WAX-1 0.3 0.3 0.3 0.3
Other
components (parts by weight) CB 1 1 1 1
Evaluation Flexural
modulus (MPa) 7200 6300 6200 6200
items Impact strength (J/m) 42
40 50 40
True density (g/cm.sup.3) 1.35 1.35 1.35 1.35
Heat resistance (.degree. C.) 110 110 110 102
Flamability V-1 V-1
V-1 V-1
Thickness of flaming test specimen (mm) 1.6 1.6 1.6 1.6
Molding shrinkage factor (%) Flow direction 0.27 0.28 0.28 0.28
Perpendicular direction 0.33 0.32 0.31 0.32
Mold wearability
evaluation .circleincircle. .circleincircle. .circleincircle.
.circleincircle.
Release load (N) 960 970 960 960
Low-viscosity lubricating oil resistance .largecircle. .largecircle.
.largecircle. .largecircle.
Ex. = Example
[0248]
2 TABLE 2
Item Ex. 5 Ex. 6 Ex. 7
Composition Component A (wt %) PC-1 58 58 61
Component B
(wt %) AS-1 12 12 12
Component C (wt %) Component C-1 MICA-2 15
15 15
Component C-2 TALC-2 10 10
WSN 7
Component D (wt %) FR-1 5
FR-3 5 5
Total of the
components A to D: parts by weight 100 100 100
Component E (parts
by weight) PTFE 0.3 0.3 0.3
Component F (parts by weight) WAX-1
0.3 0.3
Other components (parts by weight) WAX-2 0.3
CB
1 1 1
Evaluation Flexural modulus (MPa) 7000 7000 6400
items Impact strength (J/m) 46 42 40
True density (g/cm.sup.3)
1.37 1.37 1.35
Heat resistance (.degree. C.) 102 102 109
Flamability V-1 V-1 V-1
Thickness of flaming test specimen (mm)
1.6 1.6 1.6
Molding shrinkage factor (%) Flow direction 0.27 0.27
0.27
Perpendicular direction 0.31 0.31 0.33
Mold
wearability evaluation .circleincircle. .circleincircle. .largecircle.
Release load (N) 1280 960 970
Low-viscosity lubricating oil
resistance .largecircle. .largecircle. .largecircle.
Ex.
= Example
[0249]
3 TABLE 3
Item Ex. 8 Ex. 9 Ex. 10
Composition Component A (wt %) PC-1 61 61
PC-2 61
Component B (wt %) AS-1 12 12
AS-2 12
Component
C (wt %) Component C-1 MICA-3 15 15
MICA-4 15
Component C-2 TALC-2 7 7 7
Component D (wt %) FR-1 5 5 5
Total of the components A to D: parts by weight 100 100 100
Component E (parts by weight) PTFE 0.3 0.3 0.3
Component F (parts
by weight) WAX-1 0.3 0.5
Other components (parts by weight)
WAX-2 0.3
CB 1 1 1
Evaluation Flexural modulus (MPa) 6200
6200 6200
items Impact strength (J/m) 42 42 30
True
density (g/cm.sup.3) 1.35 1.35 1.35
Heat resistance (.degree. C.)
110 110 110
Flamability V-1 V-1 V-1
Thickness of flaming
test specimen (mm) 1.6 1.6 1.6
Molding shrinkage factor (%) Flow
direction 0.28 0.28 0.28
Perpendicular direction 0.34 0.34 0.34
Mold wearability evaluation .circleincircle. .circleincircle.
.circleincircle.
Release load (N) 1860 960 670
Low-viscosity lubricating oil resistance .largecircle. .largecircle.
.largecircle.
Ex. = Example
[0250]
4 TABLE 4
Item C.Ex. 1 C.Ex. 2 C.Ex. 3
Composition Component A (wt %) PC-1 61 61 62
Component B (wt %) AS-1 12 12
Component C (wt %) Component C-2
TALC-2 7 30
Inorganic filler except for MICA-5 15
Component C (wt %) GFL 22
Component D (wt %) FR-1 5 5 8
Total of the components A to D: parts by weight 100 100 100
Component E (parts by weight) PTFE 0.3 0.3 0.3
Other components
(parts by weight) WAX-1 0.3 0.3 0.3
CB 1 1 1
Evaluation
Flexural modulus (MPa) 6900 6600 6000
items Impact strength (J/m)
25 35 16
True density (g/cm.sup.3) 1.35 1.35 1.45
Heat
resistance (.degree. C.) 107 108 98
Flamability V-1 Not-V V-1
Thickness of flaming test specimen (mm) 1.6 2.0 1.6
Molding
shrinkage factor (%) Flow direction 0.27 0.23 0.19
Perpendicular
direction 0.32 0.34 0.24
Mold wearability evaluation -- X --
Release load (N) 960 -- --
Low-viscosity lubricating oil
resistance .largecircle. .largecircle. .largecircle.
C.Ex. = Comparative Example
[0251]
5 TABLE 5
Item C.Ex. 4 C.Ex. 5 C.Ex. 6
Composition Component A (wt %) PC-1 61 61 54
Component B (wt %) AS-1 12 12
AS-2 10
Component C (wt
%) Component C-1 MICA-3 22
Component C-2 TALC-2 22
Inorganic filler except for MICA-5 30
Component C (wt %)
Component D (wt %) FR-1 5 5
FR-3 6
Total of the
components A to D: parts by weight 100 100 100
Component E (parts
by weight) PTFE 0.3 0.3 0.4
Other components (parts by weight)
WAX-1 0.3 0.3 0.3
CB 1 1 1
Evaluation Flexural modulus
(MPa) 6600 5000 10000
items Impact strength (J/m) 45 21 23
True density (g/cm.sup.3) 1.35 1.34 1.42
Heat resistance
(.degree. C.) 110 108 99
Flamability Not-V V-1 V-1
Thickness of flaming test specimen (mm) 1.6 1.6 1.6
Molding
shrinkage factor (%) Flow direction 0.26 0.32 0.23
Perpendicular
direction 0.30 0.40 0.25
Mold wearability evaluation
.largecircle. .circleincircle. --
Release load (N) 960 970 --
Low-viscosity lubricating oil resistance .largecircle. .largecircle.
.largecircle.
C.Ex. = Comparative Example
[0252]
6 TABLE 6
Item Ex. 11
Composition Component P (wt %) PPE 48
Component S (wt %) HIPS 20
Component C (wt %) Component C-1 MICA-2 15
Component C-2
TALC-2 7
Component D (wt %) FR-2 10
Total of the
components A to D: parts by weight 100
Component E (parts by
weight) PTFE 0.3
Other components (parts by weight) CB 1
Evaluation Flexural modulus (MPa) 6000
items Impact strength (J/m)
30
True density (g/cm.sup.3) 1.26
Heat resistance
(.degree. C.) 102
Flamability V-1
Thickness of flaming
test specimen (mm) 2.0
Molding shrinkage factor (%) Flow
direction 0.27
Perpendicular dlrection 0.35
Mold
wearability evaluation .circleincircle.
Low-viscosity lubricating
oil resistance X
Ex. = Example
[0253] As obvious from the tables above, it is understood that the flame
retardant thermoplastic resin composition of the present invention has
high stiffness, high strength, high dimensional accuracy and excellent
flame retardancy and rarely wears away a mold.
[0254] Further, in Examples 1 and 2 out of the above Examples, the surface
roughness was measured. Plate-like test specimens measuring 150 mm
(length).times.150 mm (width).times.2 mm (thickness) were formed from the
dried pellets by injection molding (gate was a fin gate having a width of
40 mm and a thickness of 1 mm from one end of the side of the specimen)
to measure their surface roughnesses. The molding conditions of the
plate-like test specimens are as follows: injection molding machine:
SG-150U of Sumitomo Heavy Industries, Ltd., cylinder temperature:
260.degree. C., mold temperature: 50.degree. C. (temperature applied by a
chiller unit through a 20.degree. C. refrigerant is maintained), filling
time: 6 sec., dwell pressure: 75 MPa, dwell time: 3 sec., cooling time:
20 sec. The surface roughness of the plate-like test specimen was
measured by the Surfcom 1400A of Tokyo Seimitsu Co., Ltd. As a result, in
Example 1, Ra was 2.3 .mu.m and Ry was 19.1 .mu.m. In Example 2, Ra was
1.2 .mu.m and Ry was 8.2 .mu.m. They were extremely excellent when mica
having a smaller particle diameter of Example 2 was used. Ra means
arithmetic mean roughness and Ry means the maximum height. The
measurement was carried out in accordance with JIS B0601.
[0255] Chassis molded articles for optical recording medium drives were
molded from the resin compositions of Examples 1 to 11. Excellent chassis
molded articles were obtained.
[0256] Effect of the Invention
[0257] The flame retardant resin composition of the present invention can
be used in any material which needs mechanical properties such as impact
strength, flame retardancy and dimensional stability. It is particularly
effective for use in the field of OA equipment which require high
dimensional accuracy, such as optical chassis for laser beam printers
which are optical unit chassis and structural frames for laser beam
printers. The flame retardant resin composition of the present invention
has an excellent economical effect for molding because it rarely wears
away the screw of a molding machine and a mold. Therefore, its industrial
effect is remarkable.
* * * * *