U.S. patent application number 10/478996 was filed with the patent office on 2004-09-16 for flame-retardant aromatic polycarbonate resin composition.
Invention is credited to Kikuchi, Seiji.
Application Number | 20040178383 10/478996 |
Document ID | / |
Family ID | 28449436 |
Filed Date | 2004-09-16 |
United States Patent
Application |
20040178383 |
Kind Code |
A1 |
Kikuchi, Seiji |
September 16, 2004 |
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
|
Family ID: |
28449436 |
Appl. No.: |
10/478996 |
Filed: |
November 26, 2003 |
PCT Filed: |
March 27, 2003 |
PCT NO: |
PCT/JP03/03839 |
Current U.S.
Class: |
252/62 |
Current CPC
Class: |
C08L 27/18 20130101;
C08K 5/0066 20130101; C08K 3/34 20130101; C08L 69/00 20130101; C08L
35/06 20130101; C08L 71/12 20130101; C08L 71/02 20130101; C08K
5/526 20130101; C08L 25/12 20130101; C08K 3/346 20130101; C09K
21/12 20130101; C08L 33/20 20130101; C08L 25/12 20130101; C08L
2666/02 20130101; C08L 69/00 20130101; C08L 2666/02 20130101; C08L
69/00 20130101; C08L 2666/04 20130101; C08L 71/02 20130101; C08L
2666/02 20130101 |
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.
* * * * *