A flame-retarding resin composition consists essentially of (A) a graft copolymer obtained by bulk and suspension-polymerizing an aromatic monoalkenyl monomer and a vinylcyano monomer and/or a monomeric alkyl ester of acrylic acid or methacrylic acid in the presence of a diene type rubber component, as an optional ingredient (B) a graft copolymer obtained by emulsion-polymerizing a monomeric mixture of the above mentioned monomers in the presence of a diene type rubber latex, (C) a chlorinated polyethylene having a degree of chlorination of 25 to 45 wt. %, (D) tetrabromo-bisphenol A or a derivative thereof and (E) antimony trioxide.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a highly flame-retardant, impact-resistant 
resinous composition having an excellent mechanical strength and a good 
moldability. 
More specifically, the present invention relates to a highly 
flame-retardant, impact-resistant resinous composition excellent in the 
impact resistance, thermal stability, moldability and gloss, which 
consists essentially of (A) a graft copolymer obtained by 
bulk-polymerizing and suspension-polymerizing an aromatic monoalkenyl 
monomer and a vinylcyano monomer and/or a monomeric alkyl ester of acrylic 
acid or methacrylic acid in the presence of a diene type rubber component, 
optionally (B) a graft copolymer obtained by emulsion-polymerizing a 
monomeric mixture of the above-mentioned monomers in the presence of a 
diene type rubber latex, (C) a chlorinated polyethylene having a degree of 
chlorination of 25 to 45% by weight, (D) tetrabromobisphenol A or a 
derivative thereof and (E) antimony trioxide. 
2. Description of Prior Arts 
Recently, application fields of plastic materials have been broadened, and 
ABS resins are used as automobile parts, electric equipments, construction 
materials and other various molded articles in various fields because of 
their excellent impact resistance and moldability. However, with such 
broadening of application fields, various severe legal regulations are 
imposed on these plastic materials, and flame-retardant materials are now 
required to have not only a self-extinguishing property but also such a 
property that "flaming drippings" is not caused to occur at the time of 
combustion. 
As means for rendering combustible ABS resins flame-retardant, there has 
generally been adopted a method in which at least one member selected from 
relatively low-molecular-weight organic flame retardants containing 
halogens in large quantities, halogen-containing polymers such as 
polyvinyl chloride, and inorganic compounds such as antimony trioxide is 
incorporated in an ABS resin. It is known that in order to impart to ABS 
resins such high flame retardancy that "flaming drippings" is not caused 
at the time of combustion, it is effective to use a halogen-containing 
organic compound, especially a halogen-containing polymer such as 
polyvinyl chloride, chlorinated polyethylene or the like, and antimony 
trioxide in combination. 
As the typical method for production of ABS resins, there are known 
bulk-suspension polymerization and emulsion polymerization methods. For 
example, when an ABS resin is prepared according to the emulsion 
polymerization method, since a mixture of vinyl monomers is grafted to a 
rubber latex, the rubber content in the resin can optionally be changed. 
Further, since the particle size of the rubber latex is sufficiently 
small, a molded article of an ABS resin prepared by the emulsion 
polymerization method has an excellent gloss. However, an emulsifier or 
coagulant used in the preparation method is left in the resulting resin 
and has bad influences on the mechanical properties and thermal stability 
of the resin. Especially in the case a halogen-containing organic flame 
retardant and antimony trioxide are incorporated in such ABS resin in 
order to render it flame-retardent, if impurities such as the emulsifier 
and coagulant are left in the ABS resin, they promote combustibility of 
the ABS resin and excessive amounts of halogen and antimony components 
should be incorporated. Moreover, these impurities promote decomposition 
of the halogen-containing flame retardant. As a result, there are caused 
various troubles such as discoloration of the resin at the molding step 
and corrosion of an injection molding machine or a mold. 
An ABS resin prepared by the bulk-suspension polymerization method is free 
of the above-mentioned impurities such as the emulsifier. Accordingly, 
this ABS resin has a good thermal stability, and when a flame retardant is 
incorporated in this ABS resin, the amount of the halogen or antimony 
component necessary for rendering the ABS resin flame-retardant can be 
reduced more than the case of the ABS resin obtained by the emulsion 
polymerization method. Further, the discoloration at the molding step can 
be remarkably reduced. 
As another rubber-modified impact-resistant resin, there can be mentioned 
high-impact polystyrene. It is known that a larger amount of a flame 
retardant should be incorporated into an ABS resin than in this 
high-impact polystyrene if it is intended to attain the same level of the 
flame retardancy. Accordingly, high techniques are required for rendering 
ABS resins flame-retardant without other desired characteristics of ABS 
resins, namely higher impact resistance, rigidity and chemical resistance 
than those of the high-impact polystyrene. Chlorinated polyethylene which 
is often used as a flame retardancy-imparting component is poor in the 
compatibility with high-impact polystyrene, and therefore, even if 
chlorinated polyethylene is incorporated in high-impact polystyrene, the 
improvement of the impact resistance cannot be expected and such 
undesirable phenomena as reduction of the rigidity and laminar peeling are 
caused. Accordingly, from the practical viewpoint, the amount of 
chlorinated polyethylene incorporated into high-impact polystyrene should 
be limited to about 10% or less. In contrast, chlorinated polyethylene has 
a good compatibility with an ABS resin, and it is seen that when 
chlorinated polyethylene is incorporated into an ABS resin, the impact 
resistance is improved in proportion to the amount of chlorinated 
polyethylene incorporated. It is known that by incorporating a relatively 
large amount of chlorinated polyethylene into an ABS resin, it is made 
possible to render the ABS resin flame-retardant and compensate for 
reduction of the impact resistance caused by incorporation of antimony 
trioxide or the like. However, although the impact resistance is thus 
improved by incorporation of chlorinated polyethylene, the ridigity and 
moldability of the final resinous composition are reduced and the inherent 
characteristics of the ABS resin are considerably lost. In order to render 
an ABS resin highly flame-retardant while maintaining inherent 
characteristics of the ABS resin as much as possible, it is desirable to 
incorporate into the ABS resin chlorinated polyethylene, antimony trioxide 
and a halogen-containing organic flame retardant in an appropriate 
combination in minimum amounts. 
SUMMARY OF THE INVENTION 
As a result of our research works made with a view to providing a highly 
flame-retardant, highly impact-resistant resinous composition excellent in 
the mechanical strength and moldability by using ABS resin prepared by the 
bulk-suspension polymerization method and utilizing the combination of 
chlorinated polyethylene, a halogen-containing organic flame retardant and 
antimony trioxide and in addition, optionally the emulsion-polymerized ABS 
resin, we have now completed the present invention. 
More specifically, the present invention relates to a flame-retardant 
resinous composition comprising 100 parts by weight of a mixture of at 
least 20% by weight of (A) a graft copolymer obtained by polymerizing an 
aromatic monoalkenyl monomer and a vinylcyano monomer and/or a monomeric 
alkyl ester of acrylic acid or methacrylic acid in the presence of a diene 
type rubber component under bulk polymerization conditions and continuing 
the polymerization under suspension polymerization conditions to 
substantially complete the polymerization and up to 80% by weight of (B) a 
graft copolymer obtained by polymerizing an aromatic monoalkenyl monomer 
and a vinylcyano monomer and/or a monomeric alkyl ester of acrylic acid or 
methacrylic acid with a diene type rubber latex under emulsion 
polymerization conditions, 1 to 12 parts by weight of (C) a chlorinated 
polyethylene having a degree of chlorination of 25 to 45% by weight, 5 to 
25 parts by weight of (D) tetrabromobisphenol A or a derivative thereof 
and 2 to 10 parts by weight of (E) antimony trioxide. 
The present invention also provides a preferable composition including 100 
parts of a graft copolymer prepared according to the bulk-suspension 
polymerization, not using any emulsion polymerized graft copolymer. There 
is provided another preferable composition in which the bulk-suspension 
graft copolymer and the emulsion graft compolymer are containing in a 
blend ratio of the bulk suspension graft copolymer to the emulsion graft 
copolymer of 20/80 to 90/10 by weight. 
According to this invention, the composition including the graft copolymer 
(A) is very much improved in the flame-retarding property. It is added 
that the composition including the both graft copolymers (A) and (B) is 
improved in the gloss as well as the flame-retarding property. 
In general, ABS resin prepared according to the bulk-suspension 
polymerization method is free of impurities contained in an ABS resin 
prepared by the emulsion polymerization method, such as an emulsifier, a 
coagulant and the like. For this reason or the like reason, in order to 
attain the same level of the flame retardancy, the necessary amount of the 
flame retardant is ordinarily smaller in the ABS resin prepared by the 
bulk-suspension method than in the ABS resin prepared according to the 
emulsion polymerization method. However, because of the process 
limitation, in case of the ABS resin prepared according to the 
bulk-suspension polymerization process, the rubber content in the resin is 
relatively low and therefore, there is observed a defect that the impact 
strength, one of important characteristics of the ABS resin, is low and 
this defect is made conspicuous by addition of a flame retardant. It is 
seen that when an ABS resin prepared according to the emulsion 
polymerization method, which has a higher rubber content, is incorporated 
into such ABS resin prepared according to the bulk-suspension 
polymerization method, the impact resistance is improved in the resulting 
resinous composition and when a flame retardant is incorporated in this 
resinous composition, the effect observed in case of the ABS resin 
prepared according to the bulk-suspension polymerization method, namely 
the effect that the amount of the flame retardant necessary for attaining 
a certain level of the flame retardancy can be reduced, can be attained. 
Moreover, this resinous composition has a good thermal stability. 
Especially, when the flame retardant system used in the present invention, 
which comprises chlorinated polyethylene, tetrabromo-bisphenol A or its 
derivative and antimony trioxide, is employed, advantages expected in the 
case of the ABS resin prepared according to the bulk-suspension method can 
be attained substantially completely in case of the above-mentioned 
resinous composition. Accordingly, by mixing an ABS resin prepared 
according to the bulk-suspension polymerization method and an ABS resin 
prepared according to the emulsion polymerization method and incorporating 
the above flame retardant system into the mixture, there can be obtained a 
flame-retardant resinous composition excellent in the mechanical 
properties, moldability and thermal stability. 
The effect on combustion of plastics and flame retardancy of plastics 
caused various flame retardants involves a complicated mechanism including 
various chemical and physical phenomena, and at the present, such 
mechanism is not completely elucidated. However, in general, combustion of 
plastics is an oxidation reaction of combustible gases formed by thermal 
decomposition of plastics. It is construed that "flaming dripping" cause 
during this combustion is due to flow of the plastics by combustion heat, 
and that if a halogen-containing organic flame retardant is present, an 
incombustible gas of a halogen compound is generated to block air from the 
combustion surface and catch radicals of the combustible gas being 
subjected to the oxidation reaction to thereby prevent combustion. 
Antimony trioxide per se has no flame-retardant effect, but in the 
presence of a halogen, it forms a antimony halide to promote migration of 
the halogen and simultaneously, it enhances the radical-catching effect. 
Chlorinated polyethylene exerts the above-mentioned flame-retardant effect 
by the halogen and at the same time, it prevents the flow of plastics by 
combustion heat owing to gelation of double bonds formed in the polymer 
main chain by dehydrochlorination. Moreover, formation of char is promoted 
and an effect of preventing "flaming dripping" during combustion is 
manifested. 
As a result of our research works made with a view to preventing "flaming 
dripping" by incorporating chlorinated polyethylene, a halogen-containing 
organic flame retardant and antimony trioxide into an ABS resin, it was 
found that although the above-mentioned three flame retardant components 
should be incorporated in amounts exceeding certain levels, there is 
caused a surprising phenomenon that if the amount of chlorinated 
polyethylene alone is increased beyond a certain level in a resinous 
composition comprising an ABS resin prepared according to the 
bulk-suspension method and an ABS resin prepared according to the emulsion 
polymerization method, in which a high flame retardancy is attained by 
incorporation of chlorinated polyethylene, tetrabromo-bisphenol A or its 
derivative and antimony trioxide, the resinous composition becomes 
combustible again, and in order to render this composition flame-retardant 
again, it is necessary to increase the amounts of other flame retardant 
components, namely tetrabromobisphenol A or its derivative and antimony 
trioxide. More specifically, when 1 to 12 parts by weight of chlorinated 
polyethylene is used for 100 parts by weight of a resinous composition 
comprising an ABS resin prepared according to the bulk-suspension 
polymerization method and as an optional ingredient an ABS resin prepared 
according to the emulsion polymerization method, the sum of the amounts of 
tetrabromo-bisphenol A and antimony trioxide necessary for attaining the 
flame retardancy not causing "flaming dripping" is within a certain range, 
but when the amount of chlorinated polyethylene is increased beyond the 
above-mentioned range, the sum of the amounts of the halogen and antimony 
trioxide necessary for rendering the resinous composition flame-retardant 
is drastically increased. In this case, the physical properties of the 
resinous composition should naturally be degraded by the increased amounts 
of the flame retardant components, and the resulting resinous composition 
is not advantageous from the economical viewpoint because the flame 
retardants are more expensive than the resins. When chlorinated 
polyethylene is used in an amount not exceeding 12 parts by weight per 100 
parts by weight of the resins, the flame retardant action of bromine in 
tetrabromo-bisphenol A and antimony is well blanced with the gelation 
phenomenon and it is possible to render an ABS resin composition 
flame-retardant with relatively small amounts of the flame retardant 
components. According to the conventional techniques, chlorinated 
polyethylene which is a relatively cheap flame retardant is used in a 
large amount so as to improve the impact resistance as well as the flame 
retardant effect, and therefore, other flame retardant components, namely 
antimony trioxide and a halogen-containing organic flame retardant, should 
be incorporated in larger amounts. The reason why the amounts of the flame 
retardant components should be increased for attaining the intended flame 
retardant effect when the amount of chlorinated polyethylene exceeds 12 
parts by weight per 100 parts by weight of the ABS resin has not been 
elucidated. It may only be said that the combustion mechanism will 
probably be changed. For example, it is construed that the gelation effect 
by chlorinated polyethylene increases over the air-blocking effect by the 
halogen and antimony in the gas phase and the action of catching radicals 
for the oxidation reaction, and the combustion surface is renewed by 
reduction of the flow of the resin by combustion heat or is increased by 
the change of the heat conductivity of the resinous composition, which 
results in increases of the necessary amounts of the flame retardant 
components. 
As the diene type rubber components that is used for the graft copolymer 
(A) by the bulk-suspension method in the present invention, there may be 
used butadiene type rubbers, isoprene type rubbers and a copolymer of such 
a diene monomer and styrene or acrylonitrile. Among them, a polybutadiene 
or butadiene-styrene copolymer rubber having a relatively high 
stereoregularity, which is synthesized by using lithium or an organic 
metal compound catalyst, is especially preferred. The amount used of the 
diene type rubber components is not particularly critical. In general, the 
diene type rubber component is used in an amount of 2 to 40 parts by 
weight, preferably 2 to 20 parts by weight, per 100 parts by weight of a 
mixture of vinyl monomers. The average size of the dispersed rubber 
particles is 0.2 to 2.0 .mu., preferably 0.3 to 1.2 .mu.. 
Styrene is most preferred as the aromatic monoalkenyl monomer that is used 
for the graft copolymer (A). In addition, substituted styrenes such as 
.alpha.-methylstyrene and p-methylstyrene may be used, and also a mixture 
of such substituted styrene with styrene can be used. Acrylonitrile is 
most preferred as the vinylcyano monomer, but methacrylonitrile or the 
like may be used. 
As to an alkyl ester monomer of acrylic acid or methacrylic acid, there is 
preferred an ester having an alkyl of one to 18 carbon atoms, especially 
methyl methacrylate. The mixing ratio of the aromatic monoalkenyl monomer 
and the vinylcyano monomer and/or the alkyl ester of acrylic acid or 
methacrylic acid is not particularly critical, but in general, a monomeric 
mixture comprising 80 to 55% by weight of the aromatic monoalkenyl 
monomer, 0 to 45% by weight of the vinylcyano monomer and 0 to 45 wt % of 
said alkyl ester is employed. The total amount of the vinylcyano monomer 
and the alkyl ester is from 20 to 45 wt %. 
The kinds and amounts of the polymerization initiator and molecular weight 
adjusting agents that are used for the preparation of the graft copolymer 
(A) in the present invention are not particularly critical, and known 
agents may be used in known amounts. In some case, it is possible to 
perform bulk polymerization and suspension polymerization separately and 
incorporate the products obtained at both the steps simultaneously. 
Further, the suspensing dispersant is not particularly critical, and for 
example, there can be used so-called organic protective colloids such as 
polyvinyl alcohol and hydroxyethyl cellulose, and fine powders of 
inorganic salts such as calcium phosphate and magnesium hydroxide. Also 
the temperature condition is not particularly critical. In general, it is 
preferred that the bulk polymerization be carried out at 60 to 100.degree. 
C. and the suspension polymerization be carried out at 60 to 140.degree. 
C. The graft copolymer (A) includes a blend of the graft copolymer 
obtained according to the above-mentioned bulk-suspension polymerization 
method with a copolymer obtained from a mixture of the same monomers by 
the suspension polymerization method, the bulk polymerization method or 
the bulk-suspension polymerization method. 
Customary emulsion polymerization conditions are applied to the production 
of the graft copolymer (B) in the present invention. As the diene type 
rubber latex, there can be mentioned a polybutadiene latex and a latex of 
a copolymer of butadiene with styrene, acrylonitrile or a vinyl monomer 
such as methyl methacrylate. Not only a substantially uncrosslinked rubber 
but also a crosslinked, gel-containing rubber latex can be used in the 
present invention. The amount of the diene type rubber latex is not 
particularly critical, but in general, the latex is used in an amount of 
10 to 100 parts by weight per 100 parts by weight of a mixture of vinyl 
monomers. The average size of the dispersed rubber particles of the diene 
type rubber latex is 0.05 to 0.5 .mu., preferably 0.1 to 0.3 .mu.. 
The same aromatic monoalkenyl monomer and vinylcyano monomer as mentioned 
above with respect to the graft copolymer (A) can be used for the 
production of the graft copolymer (B). The mixing ratio of the vinyl 
monomers is not particularly critical, but in general, there is employed a 
mixture comprising 55 to 80% by weight of the aromatic monoalkenyl 
monomer, 0 to 45 % by weight of the vinylcyano monomer and 0 to 45 % by 
weight of the alkyl ester of acrylic or methacrylic acid. These vinyl 
monomers may be added entirely at one time at the start of polymerization, 
but in some cases, they may be added continuously or dividely in stages. 
As the surface active agent that is used for preparing the graft copolymer 
(B) according to the emulsion polymerization method, there can be 
mentioned, for example, anionic surface active agents such as sodium 
alkylbenzene-sulfonates, sodium salts of sulfuric acid esters of higher 
alcohols, sodium and potassium salts of disproportioned rosin acid, and 
sodium and potassium salts of higher fatty acids. As the polymerization 
initiator, there may be used, for example, persulfates such as potassium 
presulfate, hydroperoxides such as p-methane hydroperoxide, and 
combination initiators such as cumene hydroperoxide-Fe++-glucose. As the 
molecular weight regulating agent, there can be used known agents. 
Incidentally, the graft copolymer (B) includes a blend of the graft 
copolymer obtained according to the above-mentioned emulsion 
polymerization method with other copolymer prepared from a mixture of the 
same vinyl monomers according to the emulsion polymerization method. 
If the graft copolymer (B) is mixed in the composition of this invention, 
the mixing ratio of the graft copolymers (A) and (B) in the present 
invention is preferably such that the amount of the graft copolymer (A) is 
20 to 90 % by weight more preferably 30 to 85% by weight and the amount of 
the graft copolymer (B) is 10 to 80% by weight, more preferably 15 to 70% 
by weight. 
A highly flame-retardant resinous composition of the present invention 
formed by incorporating the flame retardant components into a resinous 
composition comprising the graft copolymers (A) and (B) at the above 
mixing ratio has well-balanced physical properties. More specifically, 
discoloration at the molding-step and corrosion of an injection molding 
machine or mold, which are inevitable in resins prepared according to the 
emulsion polymerization, are hardly caused in the resinous composition of 
the present invention, and an excellent thermal stability possessed by 
resins formed by bulk-suspension polymerization, which hardly contain 
impurities, can be retained in the resinous composition of the present 
invention. Furthermore, the mechanical strength of the resinous 
composition of the present invention is very high. 
The content of the rubber component in the composition of the present 
invention is 3 to 40% by weight, preferably 5 to 30% by weight, based on 
the sum of the graft copolymers (A) and (B). 
The composition of the present invention may further comprise a copolymer 
of vinyl monomers. More specifically, as one embodiment the present 
invention includes a flame-retardant resinous composition comprising 100 
parts by weight of a mixture of the graft copolymer (A) or a blend of this 
graft copolymer (A) with a copolymer obtained from a mixture of the same 
monomer as in the polymer (A) by the suspension, bulk or bulk-suspension 
polymerization method and the graft copolymer (B) or a blend of the graft 
copolymer (B) with a copolymer obtained from a mixture of the same 
monomers as in the copolymer (B) by the emulsion polymerization method, 
(C) 1 to 12 parts by weight of a chlorinated polyethylene having a degree 
of chlorination of 25 to 45% by weight, (D) 5 to 25 parts by weight of 
tetrabromo-bisphenol A or a derivative thereof and (E) 2 to 10 parts by 
weight of antimony trioxide. In this composition, the ingredient (B) or 
its blend are optional. 
The chlorinated polyethylene (C) having a degree of chlorination of 25 to 
45 % by weight, that is used in the present invention, is formed by 
chlorinating polyethylene, an ethylene-propylene copolymer or an 
ethylene-butene copolymer according to a customary method. It is preferred 
that bonded chlorine atoms be distributed in the polymer as uniformly as 
possible and residual crystals degrading actions as the rubber be hardly 
present. The chlorinated polyethylene is incorporated in an amount of 1 to 
12 parts by weight per 100 parts by weight of the sum of the graft 
copolymers (A) and (B). If the amount of the chlorinated polyethylene is 
smaller than 1 part by weight, attainment of the 
flaming-dripping-preventing effect cannot be expected, and if the amount 
of the chlorinated polyethylene is larger than 12 parts by weight, as 
pointed out hereinbefore, the amounts of other flame retardant components 
should be increased for attaining the intended high flame retardancy, and 
therefore, physical properties of the resinous composition are degraded 
and economical disadvantages are brought about. 
As another flame retardant (D), there is employed tetrabromo-bisphenol A or 
a derivative thereof such as a hydroxyalkyl ester having 2 to 3 carbon 
atoms, hydroxyhalogenated alkyl ether compound or oligomer of 
tetrabromo-bisphenol A. The intended effects of the present invention can 
be attained only when this flame retardant (D) is used in combination with 
other flame retardants (C) and (E). 
Antimony trioxide (E) is a component indispensable for obtaining a resinous 
composition having a high flame retardancy at a high efficiency. If 
antimony is not used and it is intended to attain the object by using the 
halogen alone, the halogen must be used in an extremely large amount. The 
tetrabromo-bisphenol A (D) and antimony trioxide (E) are in amounts of 5 
to 25 parts by weight and 2 to 10 parts by weight, respectively, when the 
sum of the graft copolymers (A) and (B) is 100 parts by weight and the 
amount of the chlorinated polyethylene (C) is 1 to 12 parts by weight. If 
these components (D) and (E) are used in smaller amounts, the intended 
flame retardancy cannot be attained. If they are used in large amounts, 
the flame retardancy becomes excessive, the physical properties of the 
final resinous composition are reduced and economical disadvantages are 
brought about. 
In addition to the foregoing indispensable components, the resinous 
composition of the present invention may further comprise additives 
customarily used in this field, such as a thermal stabilizer, an 
antioxidant, a lubricant, a coloring material and the like. 
In the present invention, mixing of the graft copolymers (A) and (B), 
chlorinated polyethylene (C), tetrabromo-bisphenol. A type flame retardant 
(D) and antimony trioxide (E) can be accomplished without any particular 
means or addition order by using a customary mixing apparatus such as a 
heat roll, a Banbury mixer or an extruder. As mentioned above, this 
invention provides another composition having very improved 
flame-retarding property, which consists essentially of 100 parts by 
weight of a graft copolymer (A) obtained by polymerizing an aromatic 
monoalkenyl monomer and a vinylcyano monomer and/or a monomeric alkyl 
ester of acrylic ester or methacrylic acid in the presence of a diene type 
rubber component under bulk polymerization conditions and continuing the 
polymerization under suspension polymerization conditions to substantially 
complete the polymerization, 1 to 12 parts by weight of a chlorinated 
polyethylene (C) having a degree of chlorination of 25 to 45% by weight, 5 
to 25 parts by weight of tetrabromo-bisphenol A or a derivative thereof 
(D) and 2 to 10 parts by weight of antimony trioxide (E). This composition 
also provides the same effects and advantages as in case of the 
composition including the graft copolymers (A) and (B). 
Furthermore, a preferable amount of a chlorinated polyethylene is from 3 to 
12 parts by weight based on 100 parts of the graft copolymers, more 
preferably 3 to 10 parts.

The present invention will now be described in detail by the following 
Examples, in which all of "parts" are by weight. 
REFERENTIAL EXAMPLE 
[Preparation of Graft Copolymers] 
Graft Copolymer (A)-1: 
A composition comprising the following components was charged in a closed 
type reaction vessel equipped with a strong stirrer. After the rubber 
component was completely dissolved, the temperature was elevated to 
70.degree. C. and bulk polymerization was conducted for 4 hours. 
______________________________________ 
Composition X: 
Styrene-butadiene rubber (Tafden 
15 parts 
2000A manufactured by Asahi Kasei 
Kogyo) 
Styrene 72 parts 
Acrylonitrile 28 parts 
Benzoyl peroxide 0.15 part 
Dicumyl peroxide 0.08 part 
t-Dodecyl mercaptan 0.35 part 
______________________________________ 
The resulting reaction mixture was transferred into another closed type 
reaction vessel filled with an aqueous dispersion comprising 100 parts of 
water, 4 parts of magnesium hydroxide and 0.05 part of sodium laurate, and 
the mixture was suspended in the aqueous dispersion by stirring. Then, the 
temperature was elevated to 120.degree. C. and suspension polymerization 
was conducted for 5 hours. The resulting polymer particles were cooled, 
and the dispersant was decomposed by hydrochloric acid and the product was 
washed with water and dried. The so obtained graft copolymer is designated 
as "copolymer (A)-1." The average rubber particle size of this graft 
copolymer (A)-1 was 0.8 .mu.. 
Graft Copolymer (A)-2: 
______________________________________ 
Composition 
Composition 
Y Z 
______________________________________ 
Styrene-butadiene rubber 
8 parts 
(Tafden 2000A manufactured 
by Asahi Kasei Kogyo) 
Styrene 62 parts 10 parts 
Acrylonitrile 28 parts 
Benzoyl peroxide 
0.15 part 
Dicumyl peroxide 
0.08 part 
t-Dodecyl mercaptan 
0.25 part 0.20 part 
______________________________________ 
The above composition Y was charged in a closed type reaction vessel 
equipped with a strong stirrer, and after the rubber component was 
completely dissolved the temperature was elevated to 70.degree. C. and 
bulk polymerization was conducted for 4 hours. At this point, the above 
composition z was added and the mixture was agitated for 10 minutes. 
The resulting reaction mixture was transferred into another closed type 
reaction vessel filled with an aqueous dispersion comprising 100 parts of 
water, 4 parts of magnesium hydroxide and 0.05 part of sodium laurate, and 
the reaction mixture was suspended in the aqueous dispersion by stirring. 
Then, the temperature was elevated to 120.degree. C. and suspension 
polymerization was conducted for 5 hours. The resulting polymer particles 
were cooled, and the dispersant was decomposed by hydrochloric acid and 
the resulting product was washed with water and dried. The so obtained 
graft copolymer is designated as "graft copolymer (A)-2." 
The average rubber particle size of the graft copolymer (A)-2was 0.37 .mu.. 
. 
Graft Copolymer (A)-3: 
______________________________________ 
Components 
______________________________________ 
Styrene-butadiene rubber (Tafden 
35 parts 
2000A manufactured by Asahi Kasei 
Kogyo) 
Styrene 75 parts 
Acrylonitrile 25 parts 
Benzoyl peroxide 0.15 part 
Dicumyl peroxide 0.08 part 
t-Dodecyl mercaptan 0.35 part 
______________________________________ 
The graft copolymer (A)-3 was prepared by using the above mentioned 
components and in the same manner as in the graft copolymer (A)-1. The 
average rubber particle size of the resulting copolymer was 0.7 .mu.. 
Graft Copolymer (B)-1: 
A graft copolymer (B) was prepared by using a polybutadiene rubber latex 
(having a rubber concentration of 50%) synthesized according to a known 
method and the following components: 
______________________________________ 
Polybutadiene latex 30 parts 
Styrene 72 parts 
Acrylonitrile 28 parts 
Potassium persulfate 0.5 part 
t-Dodecyl mercaptan 0.5 part 
Sodium salt of heterogeneous 
2 parts 
rosin acid 
Water 170 parts 
______________________________________ 
In a reaction vessel equipped with a stirrer was charged 150 parts of water 
containing, dissolved therein, the rubber latex, mercaptan, monomer 
mixture and sodium salt of heterogeneous rosin acid, and the temperature 
was elevated to 60.degree. C. At this temperature, 20 parts of water 
containing potassium persulfate dissolved therein was added over a period 
of 3 hours. Polymerization was further conducted for 3 hours at 60.degree. 
C. Hydrochloric acid was added to the resulting graft polymer and the 
temperature was elevated to coagulate the polymer, followed by 
dehydration, washing and drying. The so formed graft copolymer is 
designated as "graft copolymer (B)-1." The average rubber particle size of 
the copolymer (B)-1 was 0.1 to 0.2 .mu.. 
Graft Copolymer (B)-2: 
A graft copolymer was prepared in the same manner as described above with 
respect to the graft copolymer (B)-1 except that the amount of the 
polybutadiene latex was changed to 50 parts and the amount of t-dodecyl 
mercaptan was changed to 0.6 part. The resulting polymer is designated as 
"graft copolymer (B)-2". The average rubber particle size of the graft 
copolymer (B)-2 was 0.2 to 0.2 .mu.. 
______________________________________ 
[Preparation of Styrene-Acrylonitrile Copolymer] 
______________________________________ 
Styrene 72 parts 
Acrylonitrile 28 parts 
Lauroyl peroxide 0.34 part 
t-Dodecyl mercaptan 0.30 part 
______________________________________ 
A reaction vessel equipped with a stirrer was charged with 100 parts of 
water in which 0.5 part of hydroxyapatite and 0.01 part of sodium laurate 
were dissolved and dispersed, and the above monomer mixture was added to 
the aqueous dispersion and suspended therein by stirring. The temerature 
was elevated to 72.degree. C. and suspension polymerization was conducted 
for 10 hours. The resulting polymer particles were cooled, and the 
dispersant was decomposed by hydrochloric acid and the resulting product 
was washed with water and dried to obtain a styrene-acrylonitrile 
copolymer. 
EXAMPLE 1 
First, 85 parts of the graft copolymer (A)-1 prepared in Referential 
Example and 15 parts of the graft copolymer (B)-1 prepared in Referential 
Example were preliminarily blended with 5 parts of chlorinated 
polyethylene having a degree of chlorination of 35% (Daisolac G-235 
manufactured by Osaka Soda), 18 parts of tetrabromo-bisphenol A, 5 parts 
of antimony trioxide, 0.3 part of triphenyl phosphite as a stabilizer and 
1 part of dibutyl tin maleate, and then, the blend was pelletized by an 
extruder and molded into test pieces by an injection molding machine (the 
molding temperature being 210.degree. C.). Physical properties of the 
resulting test pieces were determined. 
EXAMPLE 2 
Test pieces were prepared in the same manner as described in Example 1 
except that the amounts of the graft copolymer (A)-1 and graft copolymer 
(B)-1 were changed to 70 parts and 30 parts, respectively. Physical 
properties of these test pieces were determined. 
EXAMPLE 3 
Test pieces were prepared in the same manner as described in Example 1 
except that each of the amounts of the graft copolymers (A)-1 and (B)-1 
was changed to 50 parts. Physical properties of these Test pieces were 
determined. 
EXAMPLE 4 
Test pieces were prepared in the same manner as described in Example 1 
except that the amounts of the graft copolymers (A)-1 and (B)-1 were 
changed to 30 parts and 70 parts, respectively. Physical properties of 
these test pieces were determined. 
COMATIVE EXAMPLE 1 
Test pieces were prepared in the same manner as described in Example 2 
except that the graft copolymer (A)-1 was not used and the amount of the 
graft copolymer (B)-1 was changed to 100 parts. Physical properties of 
these test pieces were determined. 
Results obtained in Examples 1 to 4 and Comparative Example 1 are shown in 
Table 1. 
Table 1 
__________________________________________________________________________ 
Tensile 
Impact 
strength 
strength Combustibility 
(kg/cm.sup.2) 
(kg . cm/cm) 
Discoloration 
1/8" thickness 
1/16" thickness 
__________________________________________________________________________ 
Example 1 
450 9.7 o 94V - 0 94V - 0 
Example 2 
450 10.2 o 94V - 0 94V - 0 
Example 3 
440 9.8 o 94V - 0 94V - 0 
Example 4 
440 9.3 o 94V - 0 94V - 0 
Comparative 
400 7.8 x HB HB 
Example 1 
__________________________________________________________________________ 
The tensile strength in Table 1 is one determined according to the method 
of ASTM D-638, the impact strength is one determined according to the 
method of ASTM D-256, and the combustibility is one determined according 
to the method of UL Standard No. 94. 
The discoloration was evaluated based on the naked eye observation. 
Methods of determining the physical properties in subsequent Examples were 
the same as the above-mentioned methods. 
In Examples 1 to 4, resinous compositions having good mechanical and 
thermal properties, high flame retardancy and the gloss of the mold 
article were obtained but in Comparative Example 1, even though the same 
flame retardant system was employed, the flame retardancy was 
insufficient. 
EXAMPLE 5 
Test pieces were prepared in the same manner as described in Example 2 
except that the amount of the chlorinated polyethylene was changed to 8 
parts. Physical properties of these test pieces were determined to obtain 
results shown in Table 2. 
EXAMPLE 6 
Test pieces were prepared in the same manner as described in Example 2 
except that the amount of the chlorinated polyethylene was changed to 10 
parts. Physical properties of these test pieces were determined to obtain 
results shown in Table 2. 
COMATIVE EXAMPLES 2, 3, 4, and 5 
Test pieces were prepared in the same manner as described in Example 2 
except that the amount of the chlorinated polyethylene was changed as 
shown in Table 2 and instead of tetrabromo-bisphenol A, hexabromobenzene 
was used in an amount indicated in Table 2. Physical properties of these 
test pieces were determined to obtain results shown in Table 2. 
Table 2 
__________________________________________________________________________ 
Flame Retardant System 
Chlorinated 
polyethylene 
Halogen-containing flame retardant 
Sb.sub.2 O.sub.3 
(parts) Kind Amount (parts) 
(parts) 
__________________________________________________________________________ 
Example 2 5 tetrabromo- 
18 5 
bisphenol A 
Example 5 8 " 18 5 
Example 6 10 " 18 5 
Comparative 
Example 2 20 " 18 5 
Comparative 
Example 3 30 " 18 5 
Comparative 
Example 4 10 hexabromo- 
11 5 
benzene 
Comparative 
Example 5 30 " 11 5 
Tensile 
Impact 
strength 
strength Combustibility 
(kg/cm.sup.2) 
(kg . cm/cm) 
Discoloration 
1/8" thickness 
1/16" thickness 
__________________________________________________________________________ 
Example 2 
450 10.2 o 94V - 0 94V - 0 
Example 5 
440 11.5 o 94V - 0 94V - 0 
Example 6 
440 12.6 o 94V - 0 94V - 0 
Comparative 
Example 2 
420 15.1 .increment. 
94V - 0 HB 
Comparative 
Example 3 
400 18.3 .increment. 
94V - 0 HB 
Comparative 
Example 4 
450 8.9 o HB HB 
Comparative 
Example 5 
410 13.8 .increment. 
94V - 0 HB 
__________________________________________________________________________ 
As compared with high flame-retardant resinous compositions of Examples 2, 
5 and 6 having excellent physical properties, the flame retardancy of the 
resinous compositions obtained in Comparative Examples 2 and 3 was 
reduced. More specifically, the flame retardancy was only 94V - 0 at 1/8" 
thickness and burning was caused at 1/16 "thickness. In Comparative 
Examples 4 and 5 where hexabromobenzene was used in amounts corresponding 
to the bromine amounts in tetrabromo-bisphenol A used in Examples 2, 5 and 
6, the flame retardant effect was inferior to that attained by 
tetrabromo-bisphenol A and hexabromobenzene did not show at all such a 
specificity to the amount used of chlorinated polyethylene, as is 
possessed by tetrabromobisphenol A. 
EXAMPLE 7 
Test pieces were prepared in the same manner as described in Example 2 
except that 70 parts of the graft copolymer (A)-1 obtained in Referential 
Example and 30 parts of the graft copolymer (B)-2 obtained in Referential 
Example were used. Physical properties of these test pieces were 
determined to obtain results shown in Table 3. 
EXAMPLE 8 
Test pieces were prepared in the same manner as described in Example 2 
except that the graft copolymer (A)-1, graft copolymer (B)-2 and 
styrene-acrylonitrile copolymer obtained in Referential Example were used 
in amounts of 30 parts, 40 parts and 30 parts, respectively. Physical 
properties of these test pieces were determined to obtain results shown in 
Table 3. 
EXAMPLE 9 
Test pieces were prepared in the same manner as described in Example 2 
except that 70 parts of the graft copolymer (A)-2 and 30 parts of the 
graft copolymer (B)-2 were used. Physical properties of these test pieces 
were determined to obtain results shown in Table 3. 
Table 3 
__________________________________________________________________________ 
Tensile 
Impact 
strength 
strength Combustibility 
(kg/cm.sup.2) 
(kg.cm/cm) 
Discoloration 
1/8" thickness 
1/16" thickness 
__________________________________________________________________________ 
Example 7 
420 20.3 o 94V - 0 94V - 0 
Example 8 
450 16.8 o 94V - 0 94V - 0 
Example 9 
450 11.0 o 94V - 0 94V - 0 
__________________________________________________________________________ 
EXAMPLES 10, 11 and 12 
There were blended 100 parts by weight of the bulk-suspension ABS resin 
(A)-3 prepared in Reference Example, chlorinated polyethylene having a 
chlorine content of 35 wt % (Daisolac G-235-Trade Mark-produced by Osaka 
Soda) in such an amount as shown in Table 4, 5 parts by weight of antimony 
trioxide, 16 parts by weight of tetrabromobisphenol A (TBA), 0.3 part by 
weight of triphenylphosphite and 1 part by weight of dibutyl tin maleate. 
The obtained blend was extruded into pellets and then test pieces were 
obtained by injection molding from the pellets, at 210.degree. C. 
Properties of pieces were measured and results are shown in Table 4. 
COMATIVE EXAMPLES 6 and 7 
Test pieces were obtained in the same manner as in Example 10, except for 
an amount of the chlorinated polyethylene as shown in Table 4, that is, 18 
parts and 25 parts. Results of measurement of their properties are shown 
in Table 4. 
COMATIVE EXAMPLE 8 
Test pieces were obtained in the same manner as in Example 10, except that 
10 parts by weight of hexabromobenzene (HBB) was used instead of 
tetrabromobisphenol A. Results of measurement of their properties are 
shown in Table 4. 
Table 4 
__________________________________________________________________________ 
Organic 
Chlori- 
flame Anti- 
nated 
retarding 
mony 
Tensile 
Impact Combustibility 
ABS 
poly- 
agent tri- 
strength 
strength 
1/8" 1/16" 
resin 
ethylene 
Amount 
oxide 
(kg/cm.sup.2) 
(kg . cm/mc) 
thickness 
thickness 
__________________________________________________________________________ 
Example 10 
100 
5 TBA 
16 5 410 7.5 94V - 0 
94V - 1 
Example 11 
100 
8 " " " 400 8.0 94V - 0 
94V - 0 
Example 12 
100 
10 " " " 400 9.2 94V - 0 
94V - 0 
Comparative 
Example 6 
100 
18 " " " 390 12.0 94V - 0 
94 HB 
Comparative 
Example 7 
100 
25 " " " 360 14.2 94V - 0 
94 HB 
Comparative 
Example 8 
100 
5 HBB 
10 5 430 6.5 94 HB 
94 HB 
__________________________________________________________________________