Resin composition

A resin composition containing a mixture of a polycarbonate resin and a rubber-reinforced styrene base resin which is prepared by polymerizing, in the presence of a rubbery polymer, a monomer mixture of an aromatic vinyl monomer, at least one of cyanated vinyl monomers and alkyl esters of unsaturated carboxylic acids and at least one other vinyl monomer; a polyolefin graft polymer which is prepared by polymerizing, in the presence of a crystalline polyolefin, a monomer of an aromatic vinyl monomer and at least one of cyanated vinyl monomers and alkyl esters of unsaturated carboxylic acids; and optionally a terpolymer of an olefin, an unsaturated dicarboxylic anhydride and an alkyl ester of an unsaturated carboxylic acid or an epoxy group-containing olefin copolymer of an unsaturated epoxy compound, an olefin and optionally an ethylenically unsaturated compound, which composition has good coating properties.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a resin composition. More particularly, 
the present invention relates to a resin composition which comprises a 
polycarbonate resin, a rubber-reinforced styrene base resin, a specific 
polyolefin graft polymer and optionally a specific terpolymer or an epoxy 
group-containing olefin graft polymer and has good coating properties. 
2. Description of the Related Art 
A polycarbonate resin has good mechanical and thermal properties and widely 
used in various fields. However, it has some drawbacks such as high 
molding temperature, poor flowability and large dependency of impact 
strength on a thickness of an article. To overcome such drawbacks, it is 
proposed to compound a rubber-reinforced styrene base resin such as ABS 
resin to the polycarbonate resin and such composition is used as a 
material of parts in vehicles or light electrical appliances. 
The composition comprising the polycarbonate resin and the 
rubber-reinforced styrene base resin has still some drawbacks such as poor 
chemical resistance and bad coating properties. 
To improve chemical resistance against gasoline or dioctyl phthalate, it is 
proposed to add a polyamide resin as a third component to the above 
composition. Since the polyamide resin has poor compatibility with other 
resins, a large amount of the polyamide resin cannot be compounded in the 
composition, so that the improvement of the chemical resistance has a 
limit. 
Since a thinner used for coating has a larger influence than gasoline or 
dioctyl phthalate, the resin article should be treated with a primer. 
SUMMARY OF THE INVENTION 
An object of the present invention is to provide a resin composition 
comprising a polycarbonate resin and a rubber-reinforced styrene base 
resin, which has not only good chemical resistance but also good coating 
properties and does not require primer treatment before coating. 
According to a first aspect of the present invention, there is provided a 
resin composition comprising: 
100 parts by weight of a mixture consisting of (A) 10 to 90% by weight of a 
polycarbonate resin and (B) 90 to 10% by weight of a rubber-reinforced 
styrene base resin which is prepared by polymerizing, in the presence of a 
rubbery polymer (b-1), a monomer (b-2) of 50 to 90% by weight of an 
aromatic vinyl monomer, 50 to 10% by weight of at least one monomer 
selected from the group consisting of cyanated vinyl monomers and alkyl 
esters of unsaturated carboxylic acids and 0 to 40% by weight of at least 
one other vinyl monomer which is copolymerizable therewith, and 
0.1 to 40 parts by weight of (C) a polyolefin graft polymer which is 
prepared by polymerizing, in the presence of a crystalline polyolefin 
(c-1), a monomer (c-2) of 50 to 100% by weight of an aromatic vinyl 
monomer and 50 to 0% by weight of at least one monomer selected from the 
group consisting of cyanated vinyl monomers and alkyl esters of 
unsaturated carboxylic acids. 
According to a second aspect of the present invention, there is provided a 
resin composition comprising: 
100 parts by weight of a mixture consisting of (A) 10 to 90% by weight of a 
polycarbonate resin and (B) 90 to 10% by weight of a rubber-reinforced 
styrene base resin which is prepared by polymerizing, in the presence of a 
rubbery polymer (b-1), a monomer (b-2) of 50 to 90% by weight of an 
aromatic vinyl monomer, 50 to 10% by weight of at least one monomer 
selected from the group consisting of cyanated vinyl monomers and alkyl 
esters of unsaturated carboxylic acids and 0 to 40% by weight of at least 
one other vinyl monomer which is copolymerizable therewith, and 
0.1 to 40 parts by weight a mixture of (C) a polyolefin graft polymer which 
is prepared by polymerizing, in the presence of a crystalline polyolefin 
(c-1), a monomer (c-2) of 50 to 100% by weight of an aromatic vinyl 
monomer and 50 to 0% by weight of at least one monomer selected from the 
group consisting of cyanated vinyl monomers and alkyl esters of 
unsaturated carboxylic acids and (D) a terpolymer comprising 50 to 98.5% 
by weight of an olefin, 0.5 to 10% by weight of an unsaturated 
dicarboxylic anhydride and 1 to 40% by weight of an alkyl ester of an 
unsaturated carboxylic acid in a weight ratio (C/D) of 5:95 to 95:5. 
According to a third aspect of the present invention, there is provided a 
resin composition comprising: 
100 parts by weight of a mixture consisting of (A) 10 to 90% by weight of a 
polycarbonate resin and (B) 90 to 10% by weight of a rubber-reinforced 
styrene base resin which is prepared by polymerizing, in the presence of a 
rubbery polymer (b-1), a monomer (b-2) of 50 to 90% by weight of an 
aromatic vinyl monomer, 50 to 10% by weight of at least one monomer 
selected from the group consisting of cyanated vinyl monomers and alkyl 
esters of unsaturated carboxylic acids and 0 to 40% by weight of at least 
one other vinyl monomer which is copolymerizable therewith, and 
0.1 to 40 parts by weight a mixture of (C) a polyolefin graft polymer which 
is prepared by polymerizing, in the presence of a crystalline polyolefin 
(c-1), a monomer (c-2) of 50 to 100% by weight of an aromatic vinyl 
monomer and 50 to 0% by weight of at least one monomer selected from the 
group consisting of cyanated vinyl monomers and alkyl esters of 
unsaturated carboxylic acids and (D') an epoxy group-containing olefin 
copolymer comprising an unsaturated epoxy compound, an olefin and 
optionally an ethylenically unsaturated compound in a weight ratio (C/D') 
of 5:95 to 95:5. 
DETAILED DESCRIPTION OF THE INVENTION 
The polycarbonate (A) may be aromatic polycarbonates, aliphatic carbonates 
and aliphatic aromatic polycarbonates. In general, the polycarbonate is a 
homo- or copolymer of a bisphenol such as 2,2-bis(4-oxyphenyl)alkanes, 
bis(4-oxyphenyl)ethers, and bis(4-oxyphenyl)sulfone, sulfide or sulfoxide. 
In some cases, it is possible to use a homo- or co-polymer a 
halogen-substituted bisphenol, or a branched polycarbonate prepared by 
using a branching modifier. 
A molecular weight of the polycarbonate (A) is not critical. Preferably, 
the polycarbonate (A) has a viscosity average molecular weight of 10,000 
to 100,000. 
There is no limitation on how to prepare the polycarbonate. Preferably, a 
phosgene method or a transesterification method is used. 
The rubber-reinforced styrene base resin (B) is a resin prepared by 
polymerizing, in the presence of a rubbery polymer (b-1), a monomer (b-2) 
of 50 to 90% by weight of an aromatic vinyl monomer, 50 to 10% by weight 
of at least one monomer selected from the group consisting of cyanated 
vinyl monomers and alkyl esters of unsaturated carboxylic acids and 0 to 
40% by weight of at least one other vinyl monomer which is copolymerizable 
therewith. Sometimes, the rubber-reinforced styrene base resin (B) 
contains a polymer of the monomer (b-2) in addition to the graft polymer. 
The rubbery polymer (b-1) has a glass transition temperature of not higher 
than 0.degree. C. and includes diene polymers (e.g. polybutadiene, 
styrene-butadiene copolymer, acrylonitrile-butadiene copolymer, etc.), 
ethylene-propylene copolymers (e.g. ethylene-propylene copolymer, 
ethylenepropylene-non-conjugated diene copolymer, etc.), acrylate 
copolymer, chlorinated polyethylene and the like. They may be used 
independently or as a mixture thereof. Among them, the diene polymers are 
preferred. 
The rubbery polymer may be prepared by emulsion polymerization, solution 
polymerization, suspension polymerization or bulk polymerization. When the 
emulsion polymerization is employed, a gel content is not limited and 
preferably from 0 to 95%. 
Examples of the aromatic vinyl monomer are styrene, .alpha.-methylstyrene, 
o-, m- or p-methylstyrene, tert.-butylstyrene, .alpha.-methylvinyltoluene, 
dimethylstyrene, chlorostyrene, dichlorostyrene, bromostyrene, 
dibromostyrene, vinylnaphthalene, and mixtures thereof. Among them, 
styrene is preferred. 
Examples of the cyanated vinyl monomer are acrylonitrile, 
methacrylonitrile, fumaronitrile, and mixtures thereof. Among them, 
acrylonitrile is preferred. 
Examples of the alkyl ester of unsaturated carboxylic acid are methyl 
(meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, 2-ethylhexyl 
(meth)acrylate, and mixtures thereof. Among them, methyl methacrylate is 
preferred. 
Examples of the other vinyl monomer which may constitute the 
rubber-reinforced styrene base resin (B) are unsaturated carboxylic acids 
or their anhydrides (e.g. acrylic acid, methacrylic acid, maleic acid, 
maleic anhydride, citraconic anhydride, etc.), maleimide compounds (e.g. 
maleimide, methylmaleimide, ethylmaleimide, N-phenylmaleimide, 
O-chloro-N-phenylmaleimide, etc.), and mixtures thereof. 
In the monomer mixture (b-2), amounts of (i) the aromatic vinyl monomer, 
(ii) the cyanated vinyl monomer or the alkyl ester of unsaturated 
carboxylic acid and (iii) the other vinyl monomer are (i) 50 to 90% by 
weight, (ii) 50 to 10% by weight and (iii) 0 to 40% by weight. Outside 
these ranges, the resin composition has deteriorated heat resistance and 
processability. Preferably, the amounts are (i) 50 to 80% by weight, (ii) 
50 to 20% by weight and (iii) 0 to 30% by weight. In particular, the 
monomer mixture (b-2) comprising the cyanated vinyl monomer as the monomer 
(ii) is preferred. 
There is no limitation on a ratio of the rubbery polymer (b-1) to the 
monomers (b-2). In view of heat resistance, impact resistance and 
processability, a weight ratio of the rubbery polymer (b-1) to the 
monomers (b-2) is from 5:95 to 80:20. 
In particular, the rubber-reinforced styrene base resin (B) preferably 
comprises the graft polymer having a graft ratio of 20 to 100% and a 
weight average particle size of 0.05 to 5 .mu.m and the copolymer. 
The rubber-reinforced styrene base resin (B) may be prepared by any of 
conventional polymerization methods such as emulsion polymerization, 
suspension polymerization, bulk polymerization, solution polymerization or 
a combination thereof. 
The polyolefin graft polymer (C) is a polymer prepared by polymerizing, in 
the presence of a crystalline polyolefin (c-1), a monomer (c-2) of 50 to 
100%, preferably 50 to 90% by weight of an aromatic vinyl monomer and 50 
to 0%, preferably 50 to 10 by weight of at least one monomer selected from 
the group consisting of cyanated vinyl monomers and alkyl esters of 
unsaturated carboxylic acids. 
The crystalline polyolefin (c-1) includes polyethylene and polypropylene. 
Among them, is preferred crystalline polypropylene having a swelling 
degree against a mixed monomer of acrylonitrile and styrene in a weight 
ratio of 25:75 (after one hour at 70.degree. C.) of 2 to 80% by weight, in 
particular 2 to 60% by weight. 
Examples of polyethylene are high density polyethylene, medium density 
polyethylene, low density polyethylene, linear low density polyethylene, 
etc., and examples of polypropylene are a homopolymer of propylene and a 
random or block copolymer of propylene with ethylene or .alpha.-olefin. 
They may be used independently or as a mixture thereof. 
An amorphous ethylene-propylene copolymer cannot achieve the objects of the 
present invention. 
As the aromatic vinyl monomer and the cyanated vinyl monomer, the same 
compounds as exemplified in connection with the rubber-reinforced styrene 
base resin (B) can be used. As the alkyl ester of unsaturated carboxylic 
acid, the monomers exemplified in connection with the resin (B) and also 
glycidyl acrylate or glycidyl methacrylate can be used. 
Among them, are preferred styrene as the aromatic vinyl monomer and 
acrylonitrile as the cyanated vinyl monomer. As the alkyl ester of 
unsaturated carboxylic acid, glycidyl methacrylate or methyl methacrylate 
is preferred. 
In the monomer mixture (c-2), amounts of (i) the aromatic vinyl monomer and 
(ii) the cyanated vinyl monomer or the alkyl ester of unsaturated 
carboxylic acid are (i) 50 to 100% by weight, preferably 50 to 90% by 
weight and (ii) 50 to 0% by weight, preferably 50 to 10% by weight. 
Outside these ranges, the composition has deteriorated chemical 
resistance. 
There is no limitation on a ratio of the crystalline polyolefin (c-1) to 
the monomer (c-2). In view of chemical resistance, coating properties and 
impact resistance, 20 to 200 parts by weight, preferably 20 to 100 parts 
by weight of the monomer (c-2) is used per 100 parts by weight of the 
crystalline polyolefin (c-1). 
The polyolefin graft polymer (C) may be prepared by any of conventional 
polymerization methods such as emulsion polymerization, suspension 
polymerization, bulk polymerization, solution polymerization or a 
combination thereof. 
The terpolymer (D) in the second aspect of the present invention comprises 
50 to 98.5% by weight of the olefin, 0.5 to 10% by weight of the 
unsaturated dicarboxylic anhydride and 1 to 40% by weight of the alkyl 
ester of unsaturated carboxylic acid. 
Examples of the olefin are ethylene, propylene, butene-1, 
4-methylpentene-1, and the like. Among them, ethylene and propylene are 
preferred. 
Examples of the unsaturated dicarboxylic anhydride are maleic anhydride, 
citraconic anhydride, aconitic anhydride, and the like. Among them, maleic 
anhydride is preferred. 
Examples of the alkyl ester of unsaturated carboxylic acid are methyl 
(meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl 
(meth)acrylate, hydroxymethyl (meth)acrylate, and the like. Among them, 
ethyl acrylate and butyl acrylate are preferred. 
When an amount of the olefin in the terpolymer is less than 50% by weight, 
the composition has insufficient chemical resistance. When this amount 
exceeds 98.5% by weight, the compatibility among the resins is 
deteriorated so that the impact resistance of the composition is decreased 
or the molded article suffers from cleavage. 
When an amount of the unsaturated dicarboxylic anhydride is less than 0.5% 
by weight, the composition has poor impact resistance. When this amount 
exceeds 10% by weight, heat stability and processability of the 
composition are deteriorated. 
When an amount of the alkyl ester of unsaturated carboxylic acid is less 
than 1% by weight, the compatibility among the resins is deteriorated. 
When this amount exceeds 40% by weight, the composition has insufficient 
chemical resistance and further heat resistance and stiffness of the 
composition are deteriorated so that balance among the mechanical 
properties is decreased. 
In particular, in view of chemical resistance and impact resistance, the 
terpolymer preferably comprises 55 to 96% by weight of the olefin, 1 to 8% 
by weight of the unsaturated dicarboxylic anhydride and 3 to 37% by weight 
of the alkyl ester of unsaturated carboxylic acid. 
The terpolymer (D) may be prepared by any of conventional methods. For 
example, using a cylindrical autoclave equipped with a blade type 
agitator, the olefin is charged in a first band of the autoclave, a 
mixture of the olefin, the unsaturated dicarboxylic anhydride and the 
alkyl ester of unsaturated carboxylic acid is charged in a second band of 
the autoclave and further a radical polymerization initiator (e.g. 
tert.-butyl-2-ethyl perhexanoate dissolved in a hydrocarbon is charged in 
a third band of the autoclave. Then, the polymerization is initiated by 
pressurizing the autoclave to 1000 to 2000 atm. 
The epoxy group-containing olefin copolymer (D') in the third aspect of the 
present invention is a copolymer of the unsaturated epoxy compound, the 
olefin and optionally the ethylenically unsaturated compound. There is no 
limitation on a composition of the copolymer (D'). Preferably, an amount 
of the unsaturated epoxy compound is from 0.05 to 95 % by weight. 
The unsaturated epoxy compound is a compound having an unsaturated group 
which can be copolymerizable with the olefin or the ethylencially 
unsaturated compound and an epoxy group in a molecule. 
Examples of the unsaturated epoxy compound are an unsaturated glycidyl 
ester of the formula: 
##STR1## 
wherein R is a C.sub.2 -C.sub.18 hydrocarbon group having an ethylenically 
unsaturated bond; 
an unsaturated glycidyl ether of the formula: 
##STR2## 
wherein R is the same as defined above and X is a group of the formula: 
##STR3## 
an epoxy alkene of the formula: 
##STR4## 
wherein R is the same as defined above and R' is a hydrogen atom or a 
methyl group; and p-glycidylstyrene; and the like. 
Specific examples of the unsaturated epoxy compound are glycidyl acrylate, 
glycidyl methacrylate, glycidyl itaconates, butene carboxylates, allyl 
glycidyl ether, 2-methylallyl glycidyl ether, styrene-p-glycidyl ether, 
3,4-epoxybutene, 3,4-epoxy-3-methyl-1-butene, 3,4-epoxy-1-pentene, 
3,4-epoxy-3-methylpentene, 5,6-epoxy-1-hexene, vinylcyclohexene monoxide, 
p-glycidylstyrene and the like. They may be used independently or as a 
mixture. Among them, glycidyl acrylate and glycidyl methacrylate are 
preferred. 
Examples of the olefin are ethylene, propylene butene, pentene, and 
the-like. They may be used independently or as a mixture. Among them, 
ethylene and propylene are preferred. 
Examples of the ethylencially unsaturated compound are a vinyl ester of a 
C.sub.2 -C.sub.6 saturated carboxylic acid, an ester of acrylic acid, 
methacrylic acid or maleic acid with a saturated C.sub.1 -C.sub.8 alcohol, 
halogenated vinyl, and the like. 
The ethylenically unsaturated compound is used in an amount of 50% or less, 
preferably from 0.1 to 45% weight based on the whole weight of the 
copolymer (D'). 
The epoxy group-containing copolymer (D') may be prepared by copolymerizing 
the unsaturated epoxy compound, the olefin and optionally the 
ethylenically unsaturated compound, or graft polymerizing the unsaturated 
epoxy compound in the presence of a polymer of the olefin or a copolymer 
of the olefin and the ethylenically unsaturated compound. 
Preferred examples of the epoxy group-containing olefin copolymer (D') are 
ethylene-glycidyl methacrylate copolymer, ethylene-vinyl acetate-glycidyl 
methacrylate copolymer, ethylene-methyl methacrylate-glycidyl methacrylate 
copolymer, and a graft polymer prepared by grafting glycidyl methacrylate 
to an olefin polymer (e.g. polyethylene, polypropylene, poly-1-butene, 
poly-4-methylpentene-1,ethylene-propylene copolymer, 
ethylene-propylene-diene copolymer, etc.). 
The epoxy group-containing olefin copolymer (D') may be prepared by any of 
conventional polymerization methods such as emulsion polymerization, 
suspension polymerization, bulk polymerization, solution polymerization 
and a combination thereof. 
The resin composition of the first aspect of the present invention 
comprises 100 parts by weight of the resin mixture consisting of 10 to 90% 
by weight of the polycarbonate resin (A) and 90 to 10% by weight of the 
rubber-reinforced styrene base resin (B), and 0.1 to 40 parts by weight of 
the polyolefin graft polymer (C). 
The resin composition of the second aspect of the present invention 
comprises 100 parts by weight of the resin mixture consisting of 10 to 90% 
by weight of the polycarbonate resin (A) and 90 to 10% by weight of the 
rubber-reinforced styrene base resin (B), and 0.1 to 40 parts by weight of 
the polyolefin graft polymer (C) and the terpolymer (D), and the weight 
ratio of the graft polymer (C) to the terpolymer (D) is from 5:95 to 95:5. 
The resin composition of the third aspect of the present invention 
comprises 100 parts by weight of the resin mixture consisting of 10 to 90% 
by weight of the polycarbonate resin (A) and 90 to 10% by weight of the 
rubber-reinforced styrene base resin (B), and 0.1 to 40 parts by weight of 
the polyolefin graft polymer (C) and the epoxy group-containing olefin 
copolymer (D'), and the weight ratio of the graft polymer (C) to the epoxy 
group-containing copolymer (D') is from 5:95 to 95:5. 
When the amount of the polycarbonate resin (A) is less than 10% by weight 
based on the total weight of the resin (A) and the resin (B), the 
composition has insufficient heat resistance and impact resistance. When 
this amount exceeds 90% by weight, the composition has insufficient impact 
resistance. Preferably, the resin mixture consists of 20 to 80% by weight 
of the polycarbonate resin (A) and 80 to 20% by weight of the 
rubber-reinforced styrene base resin (B). 
When the amount of the polyolefin graft polymer (C) or the total amount of 
the polyolefin graft copolymer (C) and the terpolymer (D) or the epoxy 
group-containing olefin polymer (D') is less than 0.1 parts by weight per 
100 parts of the total amount of the resins (A) and (B), the final 
composition has insufficient chemical resistance and coating properties. 
When this amount exceeds 40 parts by weight, the molded article tends to 
suffer from cleavage. In view of the balance among the mechanical 
properties, the amount of the polyolefin graft polymer (C), or the total 
amount of the polyolefin graft copolymer (C) and the terpolymer (D) or the 
epoxy group-containing olefin polymer (D') is from 0.1 to 30 parts by 
weight. 
When the weight ratio of the polyolefin graft copolymer (C) to the 
terpolymer (D) or the epoxy group-containing olefin copolymer (D') is 
outside the above range, the balance between the chemical resistance and 
the coating properties is not satisfactory. In particular, this weight 
ratio is from 10:90 to 90:10. 
There is not limitation on a sequence of mixing the components (A), (B), 
(C) and (D) or (D') and a state of each component. The components in the 
form of pellets, beads or powder may be simultaneously mixed, or two or 
more of them are premixed and then the reminder component(s) are mixed 
with the premix. The mixing can be carried out by any of conventional 
mixing means such as a Banbury mixer, rolls or an extruder. 
If necessary, any of conventional additives, reinforcing materials and/or 
fillers such as an antioxidant, a UV light absorber, a light stabilizer, 
an antistatic agent, a lubricant, a dye, a pigment, a plasticizer, a flame 
retardant, a mold release agent, glass fibers, metal fibers, carbon fibers 
and metal flakes may be compounded in the resin composition of the present 
invention. In addition, to the resin composition of the present invention, 
a thermoplastic resin such as polyamide, polyacetal, polyester, 
polyphenylene oxide, polymethyl methacrylate or polyvinyl chloride may be 
added.