JPH0959462A - Rubber-modified styreic resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a styrene resin compsn. excellent in impact strength, tensile strength, etc., by dispersing butadiene rubber particles having specified particle sizes, particle size distribution, etc., in a specific styrene-acrylic copolymer.

SOLUTION: A styrene-acrylic copolymer having a residual styrene monomer content of 1,500ppm or lower and a residual 4-vinylcyclohexene content of 1,500ppm or lower is produced by copolymerizing an acrylonitrile monomer and/or a (meth)acrylic ester monomer with a styrenic monomer, etc. A rubber- modified styrene resin compsn. is prepd. by dispersing, in a matrix comprising the styrene-acrylic copolymer, butadiene rubber particles having a number- average particle size of 0.08-0.35μm and such a particle size distribution (by number) that particles having sizes of lower than 0.1μm, 0.1-0.25μm, and higher than 0.25μm account for 19.5-99%, 0.5-60%, and 0.5-80%, respectively.

COPYRIGHT: (C)1997,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a rubber-modified styrenic resin composition, and in particular, a rubber-modified styrenic resin composition having excellent falling ball impact strength, high tensile strength and good luster and capable of producing an odorless molded article. Regarding

[0002]

2. Description of the Related Art Conventionally, as a styrene resin composition,
A group of impact-resistant resin compositions formed by dispersing a rubber-like graft copolymer in a matrix of a styrene copolymer is known. Practically, this kind of resin material used for housings of home electric appliances and molded articles for vehicles needs to have good properties such as impact resistance and high gloss, and ABS resin is required to meet this requirement. Is a typical styrenic resin composition that has been widely used for a long time.

However, usually, the higher the impact resistance of a resin, the lower the tensile strength and gloss, and conversely, the higher the tensile strength and gloss, the lower the impact resistance. This means that the impact resistance, tensile strength and gloss of the resin are at the same time related to the rubber content or the rubber particle size in the resin. As can be seen from conventional research, the higher the rubber content in the resin or the larger the rubber particle size, the better its impact resistance, and
The lower the rubber content or the smaller the rubber particle size, the higher the tensile strength and gloss. Therefore, what kind of impact strength, high tensile strength and good gloss a resin composition having different rubber particle size distribution has been studied for a long time. Also, recently in the injection molding industry, productivity improvement,
From the standpoint of cost reduction and appearance of the molded product, the molding temperature tends to be significantly increased.

However, conventional styrenic resins give off a bad odor during high temperature injection molding or extrusion molding, and from the molded products. This malodor is generally considered to be derived from mercaptan, which is added as a molecular weight modifier in the polymerization process of styrene resins. Since mercaptan has low volatility, it remains in the resin, which is considered to cause a bad odor during processing and in molded products. Various studies have been conducted to improve this problem.
For example, in U.S. Pat. No. 3,959,932, tertiary butyl mercaptan is used as a molecular weight modifier and residual mercaptan is removed by vacuum vapor stripping during processing of the resulting styrenic resin and its Although it is disclosed that the malodor of a molded article is reduced, its improving effect is not significant. Therefore, it is considered that not all the malodor generated during the processing of the styrene resin and the molded product thereof is derived from the mercaptan used as the molecular weight modifier.

[0005]

[Problems to be Solved by the Invention] In producing such a conventional thermoplastic styrene resin, it is not possible to simultaneously obtain excellent falling ball impact strength, high tensile strength, and good glossiness, and molding at the time of molding. In view of the fact that the malodor emitted from the product cannot be improved, the present inventors have studied, and as a result, have developed a novel resin composition capable of solving the above-mentioned problems, that is, the present invention has excellent falling ball impact strength and high An object of the present invention is to provide a rubber-modified styrenic resin composition having tensile strength and good luster and capable of producing an odorless (meaning that there is no or very little odor; the same applies hereinafter).

[0006]

[Means for Solving the Problems] In order to achieve the above object, the present inventor has conducted diligent research and as a result, obtained an odorless molded article having the following excellent falling ball impact strength, high tensile strength, and good luster. A rubber-modified styrenic resin composition that can be produced was found. That is, the rubber-modified styrene-based resin composition can be copolymerized with an acrylonitrile-based monomer and / or a (meth) acrylic acid ester-based monomer, a styrene-based monomer, and other optional additives. In a resin composition comprising a matrix of a styrene-acrylic copolymer obtained by copolymerizing a monomer mixture containing an unsaturated vinyl monomer and butadiene rubber particles dispersed in the matrix. , The residual styrene monomer relative to the resin composition
At 1500 ppm or less, residual 4-vinylcyclohexene is 150 p
pm or less, and the number average particle diameter of the rubber particles in the resin composition is 0.08 to 0.35 μm, and the number particle size distribution of the rubber particles is less than 0.1 μm.
Rubber particles having a particle size of 0.1 to 0.25 μm occupy 99%, occupying 0.5 to 60% of the total rubber particles, and rubber particles having a particle size of 0.25 μm occupying 0.5 to 80% of the total rubber particles. .

The styrene-acrylic copolymer forming the matrix of the styrene resin composition of the present invention comprises 50 to 90 wt% of styrene monomer, acrylonitrile monomer and / or (meth) acrylic acid ester type. Monomer 10 ~ 50wt
%, And 0 to 40 wt% of other copolymerizable monomer. Its average molecular weight is 40,000-300,000, 60,000
~ 250,000 is more preferred. Among them, as a styrene-based monomer, for example, styrene, α-methylstyrene, α
-Chlorostyrene, p-tert-butylstyrene, p-methylstyrene, o-chlorostyrene, p-chlorostyrene, 2,5-dichlorostyrene, 3,4-dichlorostyrene, 2,4,6-tribromostyrene and 2,5-dibromostyrene, divinylbenzene and the like can be mentioned, but styrene and α-methylstyrene are more preferable.

The acrylonitrile-based monomer includes acrylonitrile and methacrylonitrile, and acrylonitrile is more preferable. Examples of the (meth) acrylic acid ester-based monomer include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, and (meth) acrylic acid. Benzyl, hexyl (meth) acrylate, cyclohexyl (meth) acrylate, dodecyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate,
Examples thereof include glycidyl (meth) acrylate, γ- (meth) acryloxypropyltrimethoxysilane, and dimethylaminoethyl (meth) acrylate, with methyl methacrylate being particularly preferred.

The use ratio of the acrylonitrile-based monomer and the (meth) acrylic acid ester-based monomer is not particularly limited, but when impact strength and oil resistance are important, the acrylonitrile-based monomer is often used and the surface When importance is attached to hardness and light transmittance, a (meth) acrylic acid ester-based monomer, especially methyl methacrylate may be used in a large amount, and may be appropriately used depending on the physical property requirements.

Suitable other copolymerizable monomers include:
Maleimide-based monomers such as maleimide, N-methylmaleimide, N-isopropylmaleimide, N-butylmaleimide, N-hexylmaleimide, N-octylmaleimide, N-dodecylmaleimide, N-cyclohexylmaleimide, N-phenylmaleimide, N-2,3-
Dimethylphenylmaleimide, N-2,4-dimethylphenylmaleimide, N-2,3-diethylphenylmaleimide, N-2,4-diethylphenylmaleimide, N
-2,3-Dibutylphenylmaleimide, N-2,4-
Dibutylphenylmaleimide, N-2,6-dimethylphenylmaleimide, N-2,3-dichlorophenylmaleimide, N-2,4-dichlorophenylmaleimide, N
-2,3-dibromophenylmaleimide, N-2,4
6-tribromophenyl maleimide and the like can be mentioned.

Other copolymerizable monomers include, for example, (meth) acrylic acid monomers, maleic anhydride,
Unsaturated carboxylic acid compounds such as methylene succinic anhydride, methyl maleic anhydride, fumaric acid and their ester monomers, ethylene, propylene, 1-butene, 1
-Pentene, 4-methyl-1-pentene, ethylene chloride, vinylidene chloride, tetrafluoroethylene, chlorotrifluoroethylene, hexafluoropropylene, butadiene, propenylamine, isobutylenylamine,
Examples include vinyl acetate, ethyl vinyl ether, and methyl vinyl ketone.

The butadiene-based rubber particles dispersed in the styrene-acrylic copolymer matrix are rubber-like graft copolymers, and the butadiene-based rubber contains 100 to 50 wt% of 1,3-butadiene and CH ₂ = It is composed of 0 to 50 wt% of a copolymerizable monomer having a C <group. For example, polybutadiene; or butadiene-vinyl aromatic copolymer such as butadiene-styrene, butadiene-vinyltoluene copolymer, butadiene-acrylonitrile. Copolymer, butadiene such as butadiene-methacrylonitrile copolymer-
Unsaturated nitrile compound copolymer; butadiene such as butadiene-methyl acrylate copolymer, butadiene-ethyl acrylate copolymer, butadiene-butyl acrylate copolymer, butadiene-2-ethylhexyl acrylate copolymer There are butadiene-alkyl methacrylate copolymers such as alkyl acrylate copolymers, butadiene-methyl methacrylate copolymers, butadiene-ethyl methacrylate copolymers, and terpolymers of butadiene 50 wt% or more.

The butadiene rubber is produced by an emulsion polymerization method. At the time of production, a monomer is directly polymerized into a rubber latex having a particle diameter of 0.05 to 0.35 μm by an emulsion polymerization method. here
If the particle size is larger than 0.35 μm, there is a problem that it becomes difficult to remove the bad odor. Further, the monomer is formed into a rubber latex having a small particle size of 0.05 to 0.20 μm by an emulsion polymerization method, and the small rubber latex having a particle size of 0.22 to 0 is further prepared by a freezing method, a homogenizer treatment method or an additive aggregation method. .
A method of producing by coagulating and enlarging the rubber latex of 35 μm is mentioned. As the additive used in the additive aggregation method, acetic anhydride, hydrogen chloride, acidic substances such as sulfuric acid,
Or sodium chloride, potassium chloride, calcium chloride,
Polymer flocculants having a carboxyl group such as salts of magnesium chloride and magnesium sulfate, and methacrylic acid-acrylate copolymers (for example, methacrylic acid-butyl acrylate copolymer) are desirable.

In the production of the butadiene rubber latex used in the present invention, a rubber latex having a required particle size distribution can be produced by appropriately controlling the emulsifier addition method, the reaction temperature, the reaction rate and the monomer conversion rate. Alternatively, it is not necessary to separately use the enlargement method.

4 contained in butadiene rubber latex
-As a method of reducing vinylcyclohexene, there is an operation such as steam stripping, but bloated rubber latex has a greater amount of residual 4-vinylcyclohexene than those of non-bloated rubber latex. Easy to make rubber latex with less.

The butadiene and the copolymerizable monomer used for polymerizing the butadiene-based rubber can be added at any one time, such as a method of adding them at once or a plurality of times, or a method of continuously adding them. Although it may be added by a method, a method of continuously adding can obtain a better effect of reducing 4-vinylcyclohexene.

The rubbery polymer may be partially crosslinked.
Further, it is not necessary to use a crosslinking agent, but it may be used. The amount of the crosslinking agent is preferably 0 to 2 wt% with respect to the rubber-like polymer. Examples of the crosslinking agent include divinylbenzene, diallyl maleate, diallyl fumarate, diallyl acetate, allyl acrylate, and tetraethylene glycol dimethacrylate. The gel content of the butadiene rubber latex is not particularly limited and is usually preferably 30 to 90%, but the degree of swelling when benzene is used as a solvent is 20 to 60%.
Is preferred.

The rubber-like graft copolymer comprises butadiene rubber, styrene monomer 50 to 90 wt%, acrylonitrile monomer and / or (meth) acrylic acid ester monomer 10 to 50 wt%. , And other copolymerizable monomers of 0 to 40 wt% are graft-polymerized. The graft copolymer is produced by using a method in which a rubber-like polymer and a monomer mixture are subjected to a graft polymerization reaction. That is,
The rubbery polymer and at least one styrene-acrylic copolymer are combined by a grafting reaction. usually,
Predetermined grafting depending on the combination of various factors such as the ratio of the monomer to the rubber-like polymer, the polymerization conditions, the chemical structure of the rubber-like polymer, the rubber particle size, the charging rate of the monomer, and the chain transfer agent. You can get a rate.

As the method for producing the rubber-like graft copolymer of the present invention, there are an emulsion polymerization method, an emulsion bulk polymerization method, an emulsion suspension polymerization method and the like. Among them, the emulsion polymerization method is more preferable.

The initiator used in the above graft polymerization reaction is usually preferably 0.01 to 5.0 wt% with respect to the monomer,
Particularly, 0.1 to 3.0 wt% is the most preferable. The amount of addition is determined depending on the monomer and the polymerization reaction, but may be increased appropriately to facilitate the graft polymerization reaction. The molecular weight of the graft polymer can be adjusted by controlling the temperature during the graft polymerization reaction and / or by adding a small amount of a molecular weight modifier. As the molecular weight regulator, mercaptan, halide,
There are terpene compounds and others, and specific examples are n-dodecyl mercaptan, t-dodecyl mercaptan, carbon tetrabromide, terpinolene and α-methylstyrene dimer (2,4-diphenyl-4-methyl-1-pentene).
And the like.

In this graft polymerization reaction, the monomer mixture is usually added continuously or stepwise in the polymerization reaction, and it is desirable that the initiator is simultaneously added continuously or stepwise. As the above-mentioned initiator, a known initiator used for emulsion radical polymerization, for example, a peroxy compound and an azo compound can be used, and the addition method is to add a predetermined amount all at once or continuously or stepwise. Good. Suitable peroxy initiators include, for example:
Examples thereof include alkali metal peroxides, persulfates, perborates, peracetates, percarbonates and hydrogen peroxide. An oil-soluble initiator may also be used, and examples thereof include di-tert-butyl peroxide, benzoyl peroxide, lauroyl peroxide, oleyl peroxide, cumene hydroperoxide, and tert-butyl hydroperoxide. As the other initiator, for example, a radical catalyst by light irradiation may be used.

The graft polymerization reaction of the rubber latex and the monomer mixture is carried out under stirring in an inert gas atmosphere at a temperature of 20 to 100 ° C., and may be pressurized to 0 to 100 P.SIG, The polymerization time usually takes 2 to 10 hours, but 4 to 9
Time is more preferred.

By the way, from the result of the detailed study by the present inventor, the usual rubber-modified styrene resin releases styrene monomer and 4-vinylcyclohexene at a relatively high molding temperature and molding speed, and the rubber is It is speculated that the increase in the vaporization rate of the residue of the styrenic monomer contained in the modified styrenic resin synergistically promotes the simultaneous volatilization of 4-vinylcyclohexene, which causes the malodor of injection molding and molded articles. It

The preferred method for producing the resin composition of the present invention is to perform stripping of the graft polymer latex at an appropriate temperature and vacuum, coagulation with high temperature steam, or decompression using high temperature steam. Depending on whether stripping is performed in the state, the residual styrene-based monomer and 4-vinylcyclohexene are partially removed, and
This is a method in which the solidified graft polymer is washed with high temperature water and further dried under vacuum. Usually, the water content in the dried product is regulated to 3% or less, but it is regulated to 1% or less. Is preferred. Another preferred method is
The graft polymer coagulated without vacuum drying is washed with water, dehydrated by a centrifugal dehydrator until the water content falls to 40% or less, and the water is squeezed out by an extruder, and at the same time, a styrene-acrylic resin is used. There is a method of adding a copolymer and then melting, kneading, and extruding.

In order to obtain an odorless rubber-modified styrenic resin composition according to the present invention, the residual styrenic monomer is 1500
It is necessary to keep the concentration of 4-vinylcyclohexene at 150 ppm or less and the residual styrene monomer content is 850 ppm.
Below, 4-vinylcyclohexene is more preferably 100 ppm or less.

When the rubber particles in the polymer are small particles, 4
-It is relatively easy to reduce the amount of vinylcyclohexene, and therefore the rubber particles distributed in the matrix of the present invention are often small particles, and the number particle size distribution of the rubber particles is 0.1.
It is more preferable that the rubber particles having a size of μm or less occupy 19.5 to 99%, especially 50 to 98% of the whole rubber particles. Also,
Rubber particles with a particle size of 0.1-0.25 μm are 0.5-
It accounts for 60%, and more preferably 1 to 40%. The rubber particles with a particle size of 0.25 μm or more are 0.5 of the total rubber particles.
It is preferably 80%, particularly 1 to 70%.
When the number particle size distribution of these particles is out of the above range, the falling ball impact strength and the gloss are not well balanced. In the present invention, the number average particle diameter of the rubber particles is in the range of 0.08 to 0.35 μm, preferably 0.09 to 0.14 μm. If the number average particle diameter of the rubber particles is less than 0.08 μm, the falling ball impact strength is poor, and conversely, if it exceeds 0.35 μm, the gloss of the molded product is poor and the tensile strength is also reduced.

Specifically, the number average particle size of the rubber particles in the present invention means the osmium tetroxide (Os)
The thin film dyed with O ₄ ) was photographed with a transmission (TEM) electron microscope on an electron micrograph at a magnification of 50000 ×.
Fraction of particles with particle size di using a photograph of cm x 12 cm
fi was calculated and calculated as (Σfidi) / Σfi. Here, each rubber particle size di is shown as (maximum diameter + minimum diameter) / 2 of the particle.

The number particle size distribution in the present invention is determined as follows. That is, the number of particles was determined by particle size from a transmission electron micrograph (including 2000 or more rubber particles) of which the magnification was 25,000 times taken from the resin thin film to be measured, and the particle size was 0.1 μm. When the number of particles is less than n ₁ , the number of particles having a particle diameter of 0.1 to 0.25 μm is n ₂ , the number of particles having a particle diameter of more than 0.25 μm is n _3, and N = n ₁ + n ₂ + n ₃ ,
Number particle size distribution of particles of μm or less (% display, the same below) is (n ₁ / N) × 100, number particle size distribution of particles of 0.1 to 0.25 μm is (n ₂ / N) × 100, 0.25 μm or more The number particle size distribution of the particles is calculated by (n ₃ / N) × 100.

The proportion of the rubber component in the rubber-like graft copolymer used in the present invention is 15 to 80% by weight, preferably 45 to 75%.
The proportion of the styrene-acrylic copolymer chemically bonded to the rubber in wt%, that is, the graft ratio is preferably 20 to 150%, particularly 25 to 80% based on the weight of the rubber.

Then, in order to adjust the rubber content in the resin composition of the present invention, a styrene-acrylic copolymer can be appropriately blended separately if necessary. In this case, the mixing ratio of the rubber-like graft copolymer and the styrene-acrylic copolymer is such that the rubber component ratio in the mixture is 2 to 50 wt%, preferably 7 to 35 wt%, more preferably 10 to 25 wt%. Is decided. Here, if the ratio of the rubber component is within this range, the mixing ratio of the styrene-acrylic copolymer is 0.
%, That is, it may not be used.

The above-mentioned styrene-acrylic copolymer forming the matrix is present in the rubber-like graft copolymer, but is not bound to the rubber and is released from the styrene of the ungrafted styrene. -Means a combination of an acrylic copolymer and a styrene-acrylic copolymer blended to adjust the rubber content as described above.

When mixing these polymers, an extruder equipped with a large number of vent ports is used as a concrete means for simultaneously reducing the residual amounts of the styrene monomer and 4-vinylcyclohexene. Then, there is a method of removing the residual styrene-based monomer and 4-vinylcyclohexene by vacuum decompression at the vent port, and preferably using an extruder equipped with two or more vent ports, the degree of vacuum is increased and volatilization is performed. It improves the removal effect of the object. In addition, water or n-hexane as a devolatilization aid,
A volatile organic solvent such as n-octane may be added during extrusion mixing to enhance the action of removing the styrene monomer and 4-vinylcyclohexene. That is, when water or a volatile organic solvent is added, the escape of the volatile matter can be activated due to its volatility characteristics. Generally, the amount of water or organic solvent used is 0.1 to 15 parts by weight, preferably 0.5 to 10 parts by weight, based on 100 parts by weight of the resin composition.

Addition of water, an organic solvent, or the like as the devolatilization aid is carried out during the process of kneading the resin in the extruder.
It can be added by press-fitting through the inlet between the extruder barrel end (raw material charging hopper) and the vent port, or the inlet between both vent ports, and volatile matter can be easily removed. Such extrusion conditions can be selected.

The means for reducing the amounts of residual styrenic monomer and residual 4-vinylcyclohexene in preparing the resin composition of the present invention will be summarized below. Regarding these means, as already mentioned in the description of each item, the particle size distribution of the butadiene-based rubber particles including the polymerization step, the post-treatment step, the butadiene-based rubber particle enlargement step during the graft polymerization, etc. There are many means such as selection, dryness of the graft copolymer, addition of a devolatilization aid in the extruder, installation of many vacuum vent ports, etc. It is essential to achieve the present invention.

The rubber-modified styrenic resin composition of the present invention contains other substances, if necessary, such as antioxidants, plasticizers, processing aids, lubricants, UV absorbers, UV stabilizers,
Antistatic agents, fillers, reinforcing agents, colorants, flame retardants, flame retardant aids, heat stabilizers, coupling agents, and other additives may be added and used. Alternatively, it may be added after the polymerization reaction, before solidification, or during extrusion kneading.

As the antioxidant, a phenol-based antioxidant, a thioether-based antioxidant, a phosphorus-based antioxidant, a chelating agent, etc. are usually used, and the addition amount of the phenol-based antioxidant is 0.005 to 2.0 wt. %, Octadecyl (3,5-ditertiary butyl-
4-Hydroxyphenyl) propionate, triethylene glycol bis [3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate], pentaerythritol tetrakis [3- (3,5-ditert-butyl-4) -Hydroxyphenyl) propionate], 2-
Tert-Butyl-6- (3-tert-butyl-2-hydroxy-
5-methylbenzyl) -4-methylphenyl acrylate, 2,2'-methylenebis (4-methyl-6-tert-butylphenol), 2,2'-thiobis (4-methyl-6-
Tert-butylphenol), 2,2'-thio [diethyl-bis-3- (3,5-di-t-butyl-4-hydroxyphenyl)] propionate, 2,2'-oxamidobis-
[Ethyl-3- (3,5-ditertiarybutyl-4-hydroxyphenyl) propionate] and the like. The amount of the thioether antioxidant added is preferably 0.005 to 2.0 wt%, and typical examples thereof include distearyl thiodipropionate, dipalmityl thiodipropionate, pentaerythritol-tetrakis- (β-dodecylmethyl-thioprotonate. Pionate), dioctadecyl thioether and the like. Phosphite type antioxidants include phosphite type and phosphonite type antioxidants, and the addition amount is 0.
015 to 2.0 wt% is preferable, and typical ones are tris (nonylphenyl) phosphite, tridecylphosphite, cyclic neopentanetetraylbis (octadecylphosphite), 4,4′-butylidenebis (3-methyl-). 6-tert-butylphenyl-ditridecyl phosphite), tris (2,4-tert-butylphenyl) phosphite, or tetrakis (2,4-tert-butylphenyl) -4,4'-biphenylene diphosphonate , 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and the like.

The amount of the chelating agent added is preferably 0.001 to 2.0 wt%, and typical examples thereof include bisbenzoyl metal and ethylenediaminetetraacetic acid sodium salt. The total amount of the above-mentioned antioxidant added is usually 0.03 to 2.0 wt% with respect to the rubber-modified styrene resin composition of the present invention.

Typical examples of lubricants include metal soaps such as calcium stearate, magnesium stearate and lithium stearate, ethylenebisstearylamide, methylenebisstearylamide, palmitic acid amide, butyl stearate, cetyl stearate and polypropylene. Compounds such as glycol monostearate, behenic acid, stearic acid, silicone oil, polyethylene wax, ethylene, vinyl acetate wax and the like can be mentioned, and the total addition amount is usually relative to the rubber-modified styrene resin composition of the present invention. 0.03 to 5.0 wt%. Further, a methyl methacrylate-based processing aid for improving extrusion moldability and thermoformability can also be used.

Typical examples of the ultraviolet absorber include benzotriazole compounds and benzophenone compounds, and representative examples of the ultraviolet stabilizer include hindered amine compounds, and the total amount of these compounds is the present invention. It is usually 0.02 to 2.0 wt% with respect to the rubber-modified styrene resin composition.

Typical examples of the antistatic agent include low molecular weight compounds such as tertiary amine compounds and quaternary ammonium salt compounds, or polyamide polyether and 3-chloro-1,2-propylene oxide polymer. Permanent antistatic polymer materials are mentioned.

Typical fillers include calcium carbonate, silica, mica and the like. Typical reinforcing agents are glass fiber, carbon fiber, and various whiskers.
er) There are types. Typical examples of the colorant include titanium oxide, iron oxide, carbon black, and phthalocyanine blue.

Typical examples of the flame retardant or flame retardant aid are decabromodiphenyl ether, tetrabromobisphenol A, brominated polystyrene oligomer, brominated epoxy resin, hexabromocyclododecane, chlorinated polyethylene, triphenyl phosphate, red. Examples include phosphorus, antimony oxide, aluminum hydroxide, magnesium hydroxide, zinc borate, melamine, melamine isocyanurate, silicone powder, polytetrafluoroethylene powder, and expandable graphite.

Typical examples of the heat stabilizer include dibutyltin maleate and basic magnesium aluminum hydroxide carbonate. Further, there is a low molecular weight styrene-maleic anhydride copolymer as a thermal discoloration inhibitor, and the addition amount thereof is usually 0.1 to 1.0% by weight of the rubber-modified styrene resin composition of the present invention.

Typical examples of coupling agents include silane-based, titanate-based, and ziliconate-based compounds.

In order to modify the styrenic resin composition of the present invention, a polymer system additive having a high molecular weight may be used. Examples of the polymer system additive include bulk polymerization method, solution polymerization method and mass polymerization method. Suspension polymerization method, that is, a rubber-modified styrenic resin such as acrylonitrile-butadiene-styrene resin produced by a polymerization method using a butadiene-based rubber produced by a method other than the emulsion polymerization method, a rubber other than butadiene rubber such as EPDM, Rubber-modified styrene resin such as AES resin or AAS resin made using butyl acrylate rubber, maleic anhydride-styrene copolymer, styrene-phenylmaleimide copolymer, styrene-acrylonitrile-phenylmaleimide copolymer,
Styrene-acrylonitrile-maleic anhydride copolymer imidized with aniline, crosslinked rubber that does not undergo grafting operations, such as acrylonitrile-butadiene rubber or vinyl chloride resin, poly (meth) acrylic acid methyl resin, polycarbonate resin, polyamide Resins, polybutylene terephthalate, styrene thermoplastic elastomers, various compatibilizers and the like. The blending amount of these polymers is usually 3 to 200 parts by weight based on 100 parts by weight of the rubber-modified styrene resin composition of the present invention.

[0046]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is described in detail below with reference to examples, but the scope of the present invention is not limited by these examples.

<Production Example> (I-1) Production of butadiene rubber latex (A1): The following raw materials were placed in a reaction vessel equipped with a stirrer, a heating device and a raw material supply pipe, and reacted at 45 ° C. At the beginning, the reaction temperature is gradually raised as the conversion rate increases, and the reaction is allowed to proceed for 50 hours, followed by cooling. The conversion rate of the rubber latex (hereinafter referred to as A1) obtained thereby is 90% or more, the solid content of the latex is 41%, and the rubber number average particle diameter of the latex is 0.14 μm. Further, unreacted butadiene is removed by a steam distillation method after completion of the polymerization.

(I-2) Production of butadiene rubber latex (A2): The following raw materials were placed in a reaction vessel equipped with a stirrer, a heating device and a raw material supply pipe, and reacted at 70 ° C. for 12 hours, Cooling. The conversion rate of the rubber latex (hereinafter referred to as A2) thus obtained is 92% or more, the solid content of the latex is 40%, and the number average particle diameter of the rubber of the latex is 0.06 μm. Further, unreacted butadiene is removed by a steam distillation method after completion of the polymerization.

(I-3) Production of butadiene type rubber latex (A3): In the composition as in (I-2) above, 20% of the total amount of monomers and the total amount of potassium oleate and potassium persulfate are contained. The reaction was carried out by adding an aqueous solution containing 20% at a time, and the remaining 80% of the monomer and the remaining 80% of the aqueous solution containing potassium oleate and potassium persulfate were continuously added for 5 hours. After reacting for 9 hours at a temperature of ℃, it is cooled. The rubber latex thus obtained (hereinafter referred to as A3
The solid content of the latex is 39%, the rubber number average particle diameter of the latex is 0.07 μm, and the unreacted butadiene is steam distilled after the weight is finished. Remove by method.

(II) Synthesis of a carboxyl group-containing copolymer latex having a hypertrophic effect; its components are as follows. : The above components are charged in a polymerization reaction apparatus and a polymerization reaction is carried out at a temperature of 70 ° C. for 4 hours. Conversion rate is 98% or more, pH is 6.1
Thus, a latex having an average particle size of 0.07 μm was obtained.

(III-1) Production of Enlarged Rubber Latex (C1); Carboxyl Group-Containing Copolymer Having Enlargement Effect Based on 100 Parts by Weight (Solid Content) of the Butadiene Rubber Latex (A2) 1.5 parts by weight of latex (II) (solid content) and sodium sulfate as an inorganic electrolyte were added for 5 seconds and stirred, followed by stirring for 30 minutes to obtain a bloated rubber latex having a number average particle size of 0.38 μm (hereinafter referred to as C1 and Named).

(III-2) Production of Enlarged Rubber Latex (C2); Carboxyl Group-Containing Copolymer Having Enlargement Effect Based on 100 Parts by Weight (Solid Content) of the Butadiene Rubber Latex (A2) Latex (II) 1.8 parts by weight (solid content) and sodium sulfate as an inorganic electrolyte were added and stirred for 5 seconds, and subsequently stirred for 30 minutes to obtain a bloated rubber latex having a number average particle diameter of 0.45 μm (hereinafter referred to as C2 and Named).

(III-3) Production of enlarged rubber latex (C3): 100 parts by weight (solid content) of the butadiene rubber latex (A3) was subjected to the same enlargement treatment as in the above (III-2). When applied, an enlarged rubber latex (hereinafter referred to as C3) having a number average particle diameter of 0.43 μm is obtained.

Example 1 (1) Production of graft copolymer: 100 parts by weight (solid content) of the butadiene rubber latex (A1) shown in Table 1 in a nitrogen atmosphere, and as a chain transfer agent also shown in Table 1 0.2 parts by weight of t-dodecyl mercaptan (TDM), 0.32 parts by weight of cumene hydroperoxide, 0.2 parts by weight of rongalite,
After charging 2 parts by weight of potassium oleate and 200 parts by weight of water into the reactor, 70 parts by weight of styrene and 30 parts by weight of acrylonitrile are continuously mixed and added, and the graft polymerization reaction is performed at a temperature of 60 ° C for 8.5 hours. Graft polymer G1 having a conversion of 94% was obtained, and the number particle size distribution and number average particle size of the rubber particles are as shown in Table 2.

Further, a graft copolymer is prepared by the same method.
Got G2-G8.

[0056]

[Table 1]

(2) Production of resin composition: A 5% aqueous solution of sulfuric acid was added to the above graft copolymer latex G1,
Stir at 90 ° C for 10 minutes and remove the solidified precipitate by 112
After stripping with steam at 4 ° C, 4 kg / cm ² ,
Dehydrated and washed with hot water at 80 ° C, then at 80 ° C, 120 Torr
And dried for 1 hour to obtain a graft copolymer powder.
The graft copolymer powder and styrene-acrylonitrile copolymer (the composition weight ratio; acrylonitrile / styrene = 30/70, molecular weight 12,000) were mixed to give a total rubber content.
Make a mixture of 19wt%, and for 100wt% of this mixture,
2,6-di-tert-butyl-4-methylphenol 0.1wt
%, Tris (nonylphenyl) phosphite 0.1wt
%, Ethylenebisstearylamide 2% by weight, etc., and further extruded at 240 ° C. by a ZSK-35 type twin-screw extruder of Werner & Pfleiderer of Germany, and the first vent port (V1 ) And the second vent port (V2) are regulated to 150 Torr and 60 Torr respectively, and the inlet between the raw material charging hopper and the first vent port (V1) and the first and second vents are controlled. At the inlet between the ports (V1, V2), n as a devolatilization aid as described in Table 3
-Add hexane. The added amounts are 2.5 parts by weight and 1.8 parts by weight, respectively, relative to 100 parts by weight of the resin composition.

Examples 2 to 7 A resin composition was obtained by using the same treatment method as in Example 1. The difference from Example 1 was that a mixture of different graft copolymers as shown in Table 2 was used (see Table 1 for the respective graft copolymers), and solidified precipitates of the graft copolymers were used. In the subsequent treatment, as shown in Table 3, stripping, drying and extrusion conditions are adjusted to obtain a desired final resin composition.

[0059]

[Table 2]

[0060]

[Table 3]

Example 8 (1) Production of graft copolymer: 200 parts by weight (solid content) of butadiene rubber latex (A1) in a nitrogen atmosphere, 0.2 part by weight of α-methylstyrene dimer as a chain transfer agent, third Butyl hydroperoxide 0.32 parts by weight, longalite
After 0.2 part by weight, 2 parts by weight of potassium oleate and 200 parts by weight of water were charged in a reactor, 70 parts by weight of styrene and 30 parts by weight of acrylonitrile were mixed and continuously added, and further at 60 ° C.
When the graft polymerization reaction is performed for 8.5 hours, a graft polymer with a conversion rate of 93.6% is obtained, and the number particle size distribution of the rubber particles is such that particles having a particle size of less than 0.1 μm account for 62.4% and a particle size of 0.1.
Particles of ˜0.25 μm occupy 32.4%, particles exceeding 0.25 μm in particle size occupy 5.2%, and number average particle diameter is 0.14 μm.

(2) Production of resin composition: A 5% aqueous solution of sulfuric acid was added to the above graft copolymer latex to give 90
Stir at 10 ℃ for 10 minutes, and dehydrate the solidified precipitate.
It was washed with hot water at 40 ° C to obtain a graft polymer powder having a water content of 31.2%. This graft copolymer powder and a styrene-acrylonitrile-phenylmaleimide copolymer (the composition weight ratio; acrylonitrile / styrene / phenylmaleimide = 22/70/8, molecular weight 108,000) were mixed to obtain a mixture having a rubber content of 19 wt%. Make up and mix 1
2,6-di-tert-butyl-4-methylphenol 0.1 wt%, tris (nonylphenyl) phosphite 0.1 wt%, ethylenebisstearylamide 2 wt% relative to 00 wt%
Etc. are added, and the mixture is further extruded at 240 ° C. by a TEM-35 type twin-screw extruder manufactured by Toshiba Machine Co., Ltd., and the first vent port (V1) and second vent port of the extruder are extruded. The vacuum degree of (V2) is regulated to 90 Torr and 20 Torr, respectively.

Example 9 (1) Production of graft copolymer: 200 parts by weight (solid content) of butadiene rubber latex (A1) in a nitrogen atmosphere, 0.2 part by weight of TDM as a chain transfer agent also shown in Table 1, Tertiary butyl hydroperoxide 0.32 parts by weight, Rongalite 0.2
1 part by weight, 2 parts by weight of potassium oleate and 200 parts by weight of water are charged into a reactor, 70 parts by weight of styrene and 30 parts by weight of acrylonitrile are mixed and continuously added, and grafting is further performed at a temperature of 40 ° C. for 8.5 hours. When the polymerization reaction is performed, the conversion rate is 94.2%
Of the rubber particles, the number average particle size of the rubber particles is 0.14 μm, and the number particle size distribution is such that particles having a particle size of less than 0.1 μm account for 62.3% and particles having a particle size of 0.1 to 0.25 μm. 32.
4% occupies 5.3% of particles having a particle size of more than 0.25 μm.

(2) Production of resin composition: A 5% aqueous solution of sulfuric acid was added to the above graft copolymer latex to prepare 90
Stir at 10 ° C for 10 minutes, and remove the solidified precipitate at 112 ° C,
After stripping with 4 kg / cm ² steam for 90 minutes, dehydration and washing with hot water at 80 ° C are performed to obtain a water content of 29.8.
% Graft copolymer powder is obtained. This graft copolymer powder and a styrene-acrylonitrile copolymer (the composition weight ratio; acrylonitrile / styrene = 30/70, molecular weight 120,000) were mixed to form a mixture having a total rubber content of 19 wt%, in which case the mixture was 100 wt%. 2,6-di-tert-butyl-4-methylphenol 0.1 wt%, tris (nonylphenyl) phosphite 0.1 wt%, ethylenebisstearylamide 2 wt%, etc. were added, and the product of Nippon Toshiba Machine Co., Ltd. was added. Extruded by a TEM-35 type twin-screw extruder at 240 ° C., and the vacuum degree of the first vent port (V1) and the second vent port (V2) of the extruder was 150 Torr and 60 Torr, respectively.
Regulated as well as raw material charging hopper and first vent port
(V1) and the second vent port (V1, V2) at the respective injection ports, n-hexane for 100 parts by weight of the resin composition.
Press in 2.5 parts and 1.8 parts by weight.

Example 10 (1) Preparation of graft copolymer: 300 parts by weight (solid content) of butadiene rubber latex (A1) in a nitrogen atmosphere, 0.2 part by weight of α-methylstyrene dimer as a chain transfer agent, cumene hydro Peroxide 0.32 parts by weight, Rongalite 0.2
1 part by weight, 2 parts by weight of potassium oleate and 200 parts by weight of water were charged into a reactor, and then 60 parts by weight of styrene, 10 parts by weight of α-methylstyrene, 2 parts by weight of methyl methacrylate and 28 parts by weight of acrylonitrile were mixed. Continuous addition, 60 ℃
When the graft polymerization reaction is performed for 8.5 hours, the conversion rate is 93.6%.
The number average particle diameter of the rubber particles is 0.14 μm, the number particle size distribution is 0.1 μm or less 62.0%, 0.1-0.25 μm 33.6%, 0.25 μm or more. It accounts for 4.4%.

(2) Production of resin composition: A sulfuric acid aqueous solution having a concentration of 5% was added to the above graft copolymer latex to obtain 90
Stir at 10 ° C for 10 minutes, and remove the solidified precipitate at 112 ° C,
After stripping with 4 kg / cm ² water vapor for 60 minutes, dehydration and washing with hot water at 80 ° C are performed to obtain a water content rate.
29.2% of graft polymer powder was obtained. This graft copolymer powder and styrene-α-methylstyrene-acrylonitrile-methyl methacrylate copolymer (the composition weight ratio; acrylonitrile / styrene / α-methylstyrene / methyl methacrylate = 28/50/18/4, molecular weight 132,00
0) are mixed to form a mixture having a rubber content of 19 wt%, wherein 2,6-di-tert-butyl-4 is added to 100 wt% of the mixture.
-Methylphenol 0.1wt%, tris (nonylphenyl) phosphite 0.1wt%, ethylenebisstearylamide 2wt%, etc. were added, and T-manufactured by Toshiba Machine Co., Ltd.
It is extruded by an EM-35 type twin screw extruder at 240 ° C., and the vacuum degree of the first vent port (V1) and the second vent port (V2) of the extruder is regulated to 120 Torr and 40 Torr, respectively.

Comparative Examples 1 to 4 The same processing method as in Example 1 is adopted. The difference from Example 1 is that various different graft copolymers shown in Table 2 were used, and the subsequent treatment of the precipitate obtained by solidification of the graft copolymer was stripped and dried as shown in Table 3. And setting extrusion conditions to obtain a desired final resin composition.

<Performance Evaluation> Test pieces were prepared from the resin compositions obtained in the above Examples and Comparative Examples and tested for falling ball impact strength, surface gloss, tensile strength and physical properties such as residual monomer and odor. I went. The results are shown in Table 4. Each test was conducted according to the following method. 1. Falling ball impact strength; radius 50mm, thickness 3 by injection molding machine
The maximum energy at which the disk was not destroyed was obtained by injecting a mm disk test piece and dropping a 5 kg steel ball at the temperature of 23 ° C to the center of the disk to make it collide (unit: kgcm). . 2. Surface gloss; molding temperature of 230 ℃ and injection molding machine
50 mm (width) x 90 mm (length) x at 280 ° C
A 3 mm (thickness) disc test piece is injected. Five disc test pieces were measured with a 60 degree incident light using a gloss meter, and the average value was calculated (unit:%). 3. Tensile strength; measured by ASTM D-638 (Unit: kg / c
m ² ). 4. Residual amount of styrene-based monomer and 4-vinylcyclohexene; residual amount of styrene-based monomer and 4-vinylcyclohexene is the same as dimethylformamide (D
(Hereinafter abbreviated as MF), and the resin composition solution is further manufactured by Hewlettpackard.
It was analyzed by a gas color code (GC) equipped with a flame ionization detector (FID) number 5890A. 5. Molded product odor test: The resin composition odor test was conducted by forming pellets of the resin composition with an extruder, sealing 150 g of the pellets in a glass bottle, and cooling the pellets. A keen person opened the glass bottle to smell the degree of the odor, and the grade was determined by the number of persons who were recognized as having the odor, and the grade was indicated by the following symbols. Number of people recognized as having an odor Label 2 or less ◎ 2 to 4 ○ 4 to 8 △ 8 or more ×

[0069]

[Table 4]

[0070]

As can be seen from the above description and Table 4,
The rubber-modified styrenic resin composition of the present invention suppresses the residual styrene-based monomer to 1500 ppm or less and 4-vinylcyclohexene to 150 ppm or less, respectively, and the number average particle diameter of the rubber particles and the number particle size distribution thereof. Since it has been kept in an optimum state, it has excellent falling ball impact strength, high tensile strength and favorable luster, and it is possible to significantly reduce the bad odor during molding to make an odorless molded product, and therefore the present invention It can be said that such a composition has novelty and inventive step.

Claims (5)

[Claims] 1. An acrylonitrile-based monomer and / or a (meth) acrylic acid ester-based monomer, a styrene-based monomer, and other copolymerizable unsaturated vinyl-based monomer added as necessary. A resin composition comprising a matrix of a styrene-acrylic copolymer obtained by copolymerizing a monomer mixture containing a polymer and butadiene rubber particles dispersed in the matrix, wherein a residual styrene monomer is used. Is 1500 ppm with respect to the resin composition
Below, residual 4-vinylcyclohexene is 150ppm or less, and the number average particle size of the rubber particles in the resin composition is 0.08 to 0.35μm, the number particle size distribution of the rubber particles is less than 0.1μm. Rubber particles account for 19.5 to 99% of all rubber particles
, Rubber particles having a particle size of 0.1 to 0.25 μm occupy 0.5 to 60% of the total rubber particles, and rubber particles having a particle size of more than 0.25 μm occupy 0.5 to 80% of the total rubber particles. Styrenic resin composition. 2. The rubber particles having a number average distribution of the rubber particles in the resin composition of less than 0.1 μm are 50 to 50% of the whole rubber particles.
Rubber particles having a particle size of 0.1 to 0.25 μm occupy 1 to 40% of the total rubber particles, and rubber particles having a particle size of more than 0.25 μm occupy 1 to 70% of the total rubber particles. The rubber-modified styrene resin composition according to claim 1. 3. The number average particle diameter of the rubber particles is 0.09 to 0.
The rubber-modified styrenic resin composition according to claim 1, wherein the rubber-modified styrenic resin composition has a thickness of 14 μm. 4. The residual styrene-based monomer is 850 ppm or less with respect to the resin composition.
The rubber-modified styrenic resin composition according to the above. 5. The rubber-modified styrene resin composition according to claim 1, wherein the residual 4-vinylcyclohexene is 100 ppm or less based on the resin composition.