JP7200542B2 - Acrylic rubber graft copolymer and thermoplastic resin composition - Google Patents

Description

TECHNICAL FIELD The present invention relates to acrylic rubber-based graft copolymers, thermoplastic resin compositions, and thermoplastic resin molded articles that are useful as various industrial materials.

In recent years, production at overseas production bases has been accelerating from the viewpoint of cost reduction, avoidance of trade barriers, and stable product supply. In this case, it is necessary to transport the necessary raw materials to overseas production bases. There is a problem that classification tends to occur during the production of a thermoplastic resin composition by blending with a hard resin. This increases the demand for materials with higher bulk densities and storage stability.

On the other hand, styrene-based rubber reinforced resins, represented by ABS resins, have moldability and impact properties, as well as secondary workability such as paintability and plating properties. It is used in a wide range of applications such as automobiles and building materials, but recently, for the purpose of weight reduction and cost reduction, molded products have been made thinner, more fluid, less coated, and multi-purpose with a single material. As a result, there is an increasing demand for molding materials that exhibit excellent appearance stably regardless of molding conditions, in addition to impact resistance, fluidity, weather resistance, and chemical resistance.

For example, in Patent Document 1, a thermoplastic resin composition having excellent impact resistance, fluidity, surface gloss, and thermal stability and improved bronzing is disclosed as a graft copolymer having an acrylic acid ester rubber having a specific structure. There has been proposed a thermoplastic resin composition comprising a coalescence and a copolymer containing an aromatic vinyl-based monomer and an alkyl (meth)acrylate-based monomer as essential components. However, since this thermoplastic resin composition contains an alkyl (meth)acrylate monomer in the copolymer, it satisfactorily meets recent severe needs in terms of heat resistance and thermal stability during high-temperature molding. It was nothing to gain.

JP 2006-241283 A

The present invention has been made in view of the above-mentioned circumstances, and has a heat resistant resin that has excellent impact resistance, chemical resistance, surface appearance of molded products, and thermal stability during high-temperature molding, with little dependence on molding conditions for appearance performance. An object of the present invention is to provide a high bulk density acrylic rubber graft copolymer capable of providing a plastic resin composition, a thermoplastic resin composition containing this acrylic rubber graft copolymer, and a molded article thereof.

The inventors of the present invention have made intensive studies to solve the above problems, and have found that a rubbery polymer having a specific volume-average particle size containing acrylic acid alkyl ester-based monomer units and polyfunctional monomer units The present inventors have found that the above problems can be solved by using a specific acrylic rubber-based graft copolymer obtained by graft-polymerizing a vinyl-based monomer to the polymer.
That is, the gist of the present invention is as follows.

[1] A graft copolymer obtained by graft-polymerizing a vinyl-based monomer in the presence of a rubber-like polymer (a) containing an acrylic acid alkyl ester-based monomer unit and a polyfunctional monomer unit. An acrylic rubber-based graft copolymer (A) characterized by satisfying all of the following physical properties (1) to (5).
(1) The rubbery polymer (a) has a volume average particle size of 100 to 300 nm.
(2) The acetone-soluble content in the methanol-insoluble content of the graft copolymer is 5 to 20% by mass.
(3) The graft ratio of the graft copolymer is 70 to 120%.
(4) 2 g of the graft copolymer whose coarse particles have been sieved through a 20-mesh sieve is placed in a 50 ml messslinder, toluene is added so that the total volume is 50 ml, and the mixture is allowed to stand at 23° C. for 24 hours. The volume of the swollen graft copolymer is 10-35 ml.
(5) The bulk density of the graft copolymer measured according to JIS-K-6720 standard is 0.40 to 0.60 g/cm ³ .

[2] The acrylic rubber graft copolymer (A) according to [1], wherein the acrylic acid alkyl ester monomer is n-butyl acrylate.

[3] The content of acrylic acid alkyl ester-based monomer units in 100% by mass of the rubbery polymer (a) is 75% by mass or more, and the content of polyfunctional monomer units is acrylate alkyl ester The acrylic rubber-based graft copolymer (A) according to [1] or [2], which is 1.0 to 3.3 parts by mass per 100 parts by mass of the system monomer units.

[4] The content of the rubber polymer (a) in 100 parts by mass of the acrylic rubber graft copolymer (A) is 10 to 90 parts by mass, and the vinyl monomer is an aromatic vinyl monomer. and an unsaturated nitrile-based monomer, wherein the ratio of the aromatic vinyl-based monomer in 100% by mass of the monomer mixture is 20 to 97% by mass. The acrylic rubber graft copolymer (A) according to any one of [1] to [3].

[5] A thermoplastic resin composition comprising the acrylic rubber graft copolymer (A) according to any one of [1] to [4].

[6] A thermoplastic resin (B) other than the acrylic rubber graft copolymer (A) is added to a total of 100 parts by mass of the acrylic rubber graft copolymer (A) and the thermoplastic resin (B). The thermoplastic resin composition according to [5], containing 95 parts by mass or less.

[7] The thermoplastic resin (B) does not contain a graft copolymer other than the acrylic rubber graft copolymer (A), or the thermoplastic resin (B) is an acrylic rubber graft copolymer ( The content of the graft copolymer other than A) is less than 30 parts by mass with respect to a total of 100 parts by mass of the acrylic rubber-based graft copolymer (A) and the thermoplastic resin (B). The thermoplastic resin composition according to [6].

[8] A thermoplastic resin molded product obtained by molding the thermoplastic resin composition according to any one of [5] to [7].

According to the present invention, it is possible to provide a thermoplastic resin composition that has little dependence on molding conditions for appearance performance, impact resistance, chemical resistance, surface appearance of molded products, and thermal stability during high-temperature molding. An acrylic rubber-based graft copolymer having a bulk density can be provided. The thermoplastic resin composition of the present invention containing the acrylic rubber-based graft copolymer of the present invention and the molded article thereof are used for vehicle interior and exterior material applications, building material applications, and home appliance applications, for which demand has been increasing in recent years. and its industrial utility value is extremely high.

Embodiments of the present invention will be described in detail below.

In the specification of the present application, the term “unit” refers to a structural portion derived from a monomer compound (monomer) before polymerization. structural portion derived from an ester-based monomer”.
In the present specification, "(meth)acryl" refers to one or both of "acryl" and "methacryl".

[Acrylic rubber graft copolymer (A)]
The acrylic rubber-based graft copolymer (A) of the present invention is obtained by adding a vinyl-based monomer It is a graft copolymer obtained by graft polymerizing a polymer, characterized by satisfying all of the following physical properties (1) to (5).
(1) The rubbery polymer (a) has a volume average particle size of 100 to 300 nm.
(2) The acetone-soluble content in the methanol-insoluble content of the graft copolymer is 5 to 20% by mass.
(3) The graft ratio of the graft copolymer is 70 to 120%.
(4) 1 g of the graft copolymer obtained by sieving coarse particles with a 20-mesh sieve was placed in a 50 ml messslinder, toluene was added so that the total volume was 50 ml, and the mixture was allowed to stand at 23° C. for 24 hours. the volume of said graft copolymer swollen body is less than 20 ml.
(5) The bulk density of the graft copolymer measured according to JIS-K-6720 standard is 0.40 to 0.60 g/cm ³ .

<Rubber polymer (a)>
The rubbery polymer (a) used in the acrylic rubber-based graft copolymer (A) of the present invention comprises acrylic acid alkyl ester-based monomer units and polyfunctional monomer units as essential components.

As the acrylic acid alkyl ester-based monomer according to the present invention, an acrylic acid alkyl ester having an alkyl group having 1 to 12 carbon atoms is desirable. Examples of such acrylic acid alkyl esters include esters of acrylic acid and alcohols having a linear or side chain of 1 to 12 carbon atoms. Specific examples include methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, isobutyl acrylate, t-butyl acrylate, and 2-ethylhexyl acrylate. 1 to 8 are preferred. These can be used alone or in combination of two or more. Among these alkyl acrylate monomers, n-butyl acrylate is particularly preferred from the viewpoint of the balance of properties. Therefore, the rubbery polymer (a) used in the present invention should contain at least 75% by mass, particularly 80 to 100% by mass, of n-butyl acrylate units in 100% by mass of alkyl acrylate monomer units. is preferred.

The content of the acrylic acid alkyl ester-based monomer unit in 100% by mass of the rubbery polymer (a) is preferably 75% by mass or more, more preferably 80% by mass or more, and particularly preferably 85% by mass or more. If the content of the acrylic acid alkyl ester-based monomer unit is less than the above lower limit, the resulting acrylic rubber-based graft copolymer (A) and thermoplastic resin composition may have poor weather resistance, impact resistance, or appearance. may decrease.

The polyfunctional monomer according to the present invention is not particularly limited, and known polyfunctional monomers can be used. Known polyfunctional monomers include allyl methacrylate, 2-propenyl acrylate, ethylene glycol dimethacrylate, 1,3-butanediol dimethacrylate (1,3-butylene dimethacrylate), 1, Di(meth)acrylic acid esters of diols such as 6-hexanediol diacrylate, divinylbenzene, triallyl isocyanurate, triallyl cyanurate, triallyl trimetate, etc. Among them, allyl methacrylate having an allyl group, acrylic acid Preferred are 2-propenyl and the like, triallyl isocyanurate having a triazine ring, triallyl cyanurate and the like, and allyl methacrylate is particularly preferred from the viewpoint of efficiency in improving physical properties of the resulting resin composition.

Each of these polyfunctional monomers may be used alone, or two or more thereof may be used in combination.

The content of the polyfunctional monomer unit in the rubbery polymer (a) is preferably 1.0 to 3.3 parts by mass per 100 parts by mass of the acrylic acid alkyl ester-based monomer unit. 0 mass parts or less is more preferable, 2.8 mass parts or less is particularly preferable, while 1.2 mass parts or more is more preferable, and 1.5 mass parts or more is particularly preferable. If the content of the polyfunctional monomer unit exceeds the above upper limit, the resulting acrylic rubber graft copolymer (A) and thermoplastic resin composition may have reduced impact resistance, and the content is less than the above lower limit. may degrade appearance and thermal stability.

In the rubbery polymer (a), in addition to the alkyl acrylate monomer unit and the polyfunctional monomer unit, if necessary, other monomers copolymerizable with the alkyl acrylate monomer may be added. Units may be included.

Other monomers copolymerizable with acrylic acid alkyl ester monomers include aromatic vinyl monomers such as styrene, α-methylstyrene and p-methylstyrene; saturated nitrile-based monomers, methacrylic acid ester-based monomers such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, and 2-ethylhexyl methacrylate; Examples include α,β-unsaturated carboxylic acid monomers such as acrylic acid, methacrylic acid and itaconic acid, and maleimide compounds such as N-phenylmaleimide and N-cyclohexylmaleimide. These can be used singly or in combination of two or more.

Furthermore, as the rubbery polymer (a), a rubbery polymer containing an acrylic acid alkyl ester-based monomer unit and a polyfunctional monomer unit, and a monomer other than the acrylic acid alkyl ester-based monomer Composite rubbers with rubber-like polymers consisting of units can also be used. In this case, examples of the rubber-like polymer composed of monomer units other than acrylic acid alkyl ester-based monomers include ethylene-propylene rubber (EPR), ethylene-propylene-diene rubber (EPDM), and diene rubber. , polyorganosiloxane, and the like. As a method for obtaining such a composite rubber, for example, in the presence of a rubber-like polymer composed of monomer units other than an alkyl acrylate monomer, polyfunctional A technique for polymerizing monomers, a rubbery polymer composed of monomer units other than acrylic acid alkyl ester monomers, and a rubber containing acrylic acid alkyl ester monomer units and multifunctional monomer units A known method such as a method of co-enlarging the polymer can be used.

The rubbery polymer (a) according to the present invention is preferably produced by emulsion polymerization of the above monomer mixture.

As the emulsifier used in the emulsion polymerization, an anionic emulsifier is preferable from the viewpoint that the stability of the latex during emulsion polymerization is excellent and the polymerization rate can be increased.
Examples of anionic emulsifiers include carboxylates (e.g., sodium sarcosinate, fatty acid potassium, fatty acid sodium, dipotassium alkenyl succinate, rosin acid soap, etc.), alkyl sulfates, sodium alkylbenzene sulfonate, sodium alkyl sulfosuccinate, polyoxy Examples include sodium ethylene nonylphenyl ether sulfate, and from the viewpoint of suppressing hydrolysis of the polyfunctional monomer, sodium sarcosinate, dipotassium alkenyl succinate, alkyl sulfate, sodium alkylbenzene sulfonate, and sodium alkyl sulfosuccinate. , sodium polyoxyethylene nonylphenyl ether sulfate, and the like are preferred, and among these, dipotassium alkenyl succinate is particularly preferred because it has excellent polymerization stability and a wide range of coagulant options. These emulsifiers may be used singly or in combination of two or more.

The volume average particle size of the rubber polymer (a) used in the acrylic rubber graft copolymer (A) of the present invention is 100 nm or more, preferably 110 nm or more. If the volume average particle size is less than the above lower limit, the impact resistance of the obtained acrylic rubber graft copolymer (A) and thermoplastic resin composition may be lowered, and the appearance performance may be highly dependent on molding conditions. The volume average particle size of the rubbery polymer (a) is 300 nm or less, preferably 290 nm or less. When the volume average particle size exceeds the above upper limit, the appearance of the resulting acrylic rubber graft copolymer (A) and thermoplastic resin composition may deteriorate.

Furthermore, the content of the rubbery polymer having a particle size of 400 nm or more is preferably 10% by mass or less, more preferably 5% by mass or less based on 100% by mass of the rubbery polymer (a). If the content of the rubbery polymer having a particle size of 400 nm or more exceeds the above upper limit, the resulting acrylic rubber graft copolymer (A) and thermoplastic resin composition may have poor appearance properties.

The volume-average particle diameters of the rubbery polymer (a) and the rubbery polymer (b) described later are measured by the method described in Examples described later.

<Vinyl monomer>
The acrylic rubber-based graft copolymer (A) of the present invention is obtained by graft-polymerizing a vinyl-based monomer in the presence of such a rubbery polymer (a).
The vinyl-based monomer used for this graft polymerization preferably contains an unsaturated nitrile-based monomer, an aromatic vinyl-based monomer, and optionally other vinyl-based monomers.

Examples of unsaturated nitrile-based monomers include acrylonitrile and methacrylonitrile. These can be used singly or in combination of two or more.

Examples of aromatic vinyl-based monomers include styrene, α-methylstyrene, vinyltoluene, and the like. These can be used singly or in combination of two or more.

Other vinyl-based monomers are monomers copolymerizable with unsaturated nitrile-based monomers and aromatic vinyl-based monomers, and unsaturated nitrile-based monomers and aromatic vinyl-based monomers It is a monomer excluding the body. Other monomers include methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, 2-ethylhexyl acrylate, methyl acrylate, ethyl acrylate, n-butyl acrylate, 2-hydroxyethyl methacrylate, methacryl glycidyl acid, N,N-dimethylaminoethyl methacrylate, acrylamide, methacrylamide, maleic anhydride, N-substituted maleimide and the like. As for other monomers, one type may be used alone, or two or more types may be used in combination.

As the vinyl-based monomer to be graft-polymerized to the rubbery polymer (a), aromatic vinyl-based monomers such as styrene and unsaturated nitrile-based monomers such as acrylonitrile are used because the resulting molded article has excellent impact resistance. Monomer mixtures with monomers are preferred, particularly mixtures of styrene and acrylonitrile.

The ratio of the unsaturated nitrile-based monomer in the monomer mixture to be graft-polymerized to the rubbery polymer (a) is preferably 3 to 50% by mass, preferably 10 to 40% in the monomer mixture (100% by mass). % by mass is more preferred. If the proportion of the unsaturated nitrile-based monomer is at least the above lower limit, the impact resistance of the resulting molded article will be good. If the proportion of the unsaturated nitrile-based monomer is equal to or less than the above upper limit, the resulting molded article will have good thermal stability.

The ratio of the aromatic vinyl-based monomer in the monomer mixture to be graft-polymerized to the rubbery polymer (a) is preferably 20 to 97% by mass, more preferably 30 to 80% in the monomer mixture (100% by mass). % by mass is more preferred. If the proportion of the aromatic vinyl-based monomer is at least the above lower limit, the resulting thermoplastic resin composition will have good moldability. If the proportion of the aromatic vinyl-based monomer is equal to or less than the above upper limit, the impact resistance of the resulting molded article will be good.

The ratio of other monomers in the monomer mixture to be graft-polymerized to the rubbery polymer (a) is preferably 50% by mass or less, more preferably 40% by mass or less, in the monomer mixture (100% by mass). preferable. If the ratio of other monomers is equal to or less than the above upper limit, the balance between impact resistance and appearance will be good.

<Production of acrylic rubber-based graft copolymer (A)>
The acrylic rubber graft copolymer (A) of the present invention is preferably produced by emulsion polymerization of the monomer mixture as described above in the presence of the rubbery polymer (a) latex.

As the emulsifier used in the emulsion polymerization, an anionic emulsifier is preferable as in the production of the rubbery polymer (a), and dipotassium alkenyl succinate is preferable from the viewpoint of suppressing hydrolysis of the polyfunctional monomer.

Polymerization initiators used in emulsion polymerization include peroxides, azo initiators, redox initiators in which an oxidizing agent and a reducing agent are combined, and the like.
During emulsion polymerization, a chain transfer agent may be used to control the degree of grafting and the molecular weight of the grafted component.

As a method for adding monomers such as aromatic vinyl monomers and unsaturated nitrile monomers in emulsion polymerization, methods such as total batch addition, divided addition, and sequential addition can be used. These methods can also be used in combination, such as adding all at once and adding the remaining amount successively. Alternatively, a method of holding for a while after adding the vinyl-based monomer and then adding a polymerization initiator to initiate polymerization can also be used.

Methods for recovering the acrylic rubber graft copolymer (A) from the latex of the acrylic rubber graft copolymer (A) obtained by emulsion polymerization include the following methods.
The latex of the acrylic rubber-based graft copolymer (A) is poured into hot water in which a coagulant is dissolved to solidify the graft copolymer. Next, the solidified graft copolymer is redispersed in water or hot water to form a slurry, and the emulsifier residue remaining in the graft copolymer is eluted into water and washed. Next, the slurry is dehydrated with a dehydrator or the like, and the resulting solid is dried with a flash dryer or the like to recover the acrylic rubber-based graft copolymer (A) as powder or particles.
In addition, the acrylic rubber graft copolymer (A) latex is optionally mixed with another polymer latex, for example, a latex of a graft copolymer other than the acrylic rubber graft copolymer (A) described below. A collection operation may be performed.

The coagulant includes inorganic acids (sulfuric acid, hydrochloric acid, phosphoric acid, nitric acid, etc.), metal salts (calcium chloride, calcium acetate, aluminum sulfate, etc.), and the like. A coagulant is appropriately selected according to the type of emulsifier. For example, when only a carboxylate (fatty acid salt, rosin acid soap, etc.) is used as an emulsifier, any coagulant may be used. In the case of using an emulsifier exhibiting , an inorganic acid is insufficient and a metal salt must be used. Inorganic acids, particularly sulfuric acid, are preferred as the coagulant in order to suppress deterioration in performance due to hydrolysis of the acrylic rubber-based graft copolymer (A).

In the acrylic rubber graft copolymer (A), the content of the rubbery polymer (a) is 10 to 90 parts by mass, particularly 20 to 80 parts by mass, per 100 parts by mass of the acrylic rubber graft copolymer (A). Parts by mass, preferably 30 to 70 parts by mass. If the content of the rubbery polymer (a) is at least the above lower limit, the resulting acrylic rubber graft copolymer (A) and the thermoplastic resin composition will have higher impact resistance, and the rubbery polymer ( If the content of a) is equal to or less than the above upper limit, the resulting acrylic rubber graft copolymer (A) and thermoplastic resin composition can maintain good appearance and thermal stability.
Therefore, in the production of the acrylic rubber graft copolymer, the rubber polymer (a) and the vinyl monomer are combined into an acrylic rubber graft copolymer having such a rubber polymer (a) content ( It is preferred to use so as to obtain A).

<Physical Properties of Acrylic Rubber Graft Copolymer (A)>
(Acetone soluble matter)
The acrylic rubber-based graft copolymer (A) of the present invention has an acetone-soluble content of 5 to 20% by mass, preferably 5 to 10% by mass, based on 100% by mass of its methanol-insoluble content. When the acetone-soluble content of the acrylic rubber-based graft copolymer (A) is within the above range, the dependency of appearance characteristics on molding conditions is reduced, thermal stability is improved, and good appearance can be maintained. . The acetone-soluble content of the acrylic rubber-based graft copolymer (A) is determined by the method described in the Examples section below.

(graft rate)
The graft ratio of the acrylic rubber-based graft copolymer (A) of the present invention is 70 to 120%, preferably 70 to 100%, particularly preferably 70 to 90%. When the graft ratio of the graft copolymer (A) is within the above range, the resulting acrylic rubber graft copolymer (A) has good bulk density and storage stability, and the acrylic rubber graft copolymer The thermoplastic resin composition obtained using coalescence (A) can retain good impact strength, chemical resistance, appearance and thermal stability. The graft ratio of the acrylic rubber-based graft copolymer (A) is determined by the method described in the Examples section below.

(Volume of toluene swollen body)
The acrylic rubber-based graft copolymer (A) of the present invention is obtained by sieving coarse particles with a 20-mesh sieve. 2 g of the graft copolymer is placed in a 50-ml measuring cylinder, and toluene is added so that the total volume becomes 50 ml. is added, and the volume of the swollen graft copolymer (hereinafter sometimes referred to as the "volume of the swollen toluene") when allowed to stand at 23° C. for 24 hours is 10 to 35 ml, preferably 10 to 35 ml. 30 ml. When the volume of the toluene-swollen body is equal to or less than the above upper limit, the bulk density and storage stability of the acrylic rubber-based graft copolymer (A) are good, and the acrylic rubber-based graft copolymer (A) is used. The resulting thermoplastic resin composition can maintain good chemical resistance, appearance and thermal stability.

(The bulk density)
The acrylic rubber-based graft copolymer (A) of the present invention has a bulk density of 0.40 to 0.60 g/cm ³ measured according to JIS-K-6720. If the bulk density is within the above range, the bulk density is high, which is preferable in terms of transportability, storage stability, and the like.

(reduced viscosity)
The acetone-soluble portion of the acrylic rubber graft copolymer (A) of the present invention preferably has a reduced viscosity of 0.3 to 0.8 g/dl, more preferably 0.4 to 0.7 g/dl. If the reduced viscosity of the acetone-soluble portion of the acrylic rubber graft copolymer (A) is at least the above lower limit, the impact strength will be higher, and if it is below the above upper limit, good appearance and moldability can be maintained. The reduced viscosity of the acetone-soluble portion of the acrylic rubber-based graft copolymer (A) is determined by the method described in the Examples section below.

[Thermoplastic resin composition]
The thermoplastic resin composition of the present invention contains the above acrylic rubber-based graft copolymer (A) of the present invention. The thermoplastic resin composition of the present invention may contain only one type of the acrylic rubber-based graft copolymer (A) of the present invention, and the monomer composition and particles of the rubbery polymer (a) Two or more kinds of acrylic rubber-based graft copolymers (A) having different diameters, monomer compositions of vinyl monomers, physical properties, etc. may be included.

<Thermoplastic resin (B)>
The thermoplastic resin composition of the present invention may contain a thermoplastic resin (B) other than the acrylic rubber graft copolymer (A). In this case, the thermoplastic resin (B) includes methyl methacrylate-styrene copolymer (MS resin), polymethyl methacrylate, polycarbonate, polybutylene terephthalate (PBT), polyester such as polyethylene terephthalate (PET), polychlorinated Polyolefins such as vinyl, polyethylene and polypropylene, styrene-butadiene-styrene (SBS), styrene-butadiene (SBR), hydrogenated SBS, styrene-isoprene-styrene (SIS) and other styrene elastomers, various olefin elastomers, various polyesters elastomer, styrene resin, polyacetal, modified polyphenylene ether (modified PPE resin), ethylene-vinyl acetate copolymer, polyphenylene sulfide (PPS), polyether sulfone (PES), polyether ether ketone (PEEK), polyarylate, liquid crystal polyester resin, polyamide (nylon), and the like. These thermoplastic resins may be used alone or in combination of two or more.

Among these, methyl methacrylate-styrene copolymer (MS resin) and polymethyl methacrylate are preferred from the viewpoint of improving weather resistance, polycarbonate is preferred from the viewpoint of improving impact resistance, and chemical resistance is improved. From the point of view, polybutylene terephthalate (PBT) is preferable, from the point of improving moldability, polyethylene terephthalate (PET) and styrene resin are preferable, and from the point of improving heat resistance, modified polyphenylene ether (modified PPE), polyamide is preferred. Styrene-based resins are particularly preferred from the viewpoint of the balance between impact resistance and moldability.

The styrenic resin has an aromatic vinyl-based monomer unit as an essential component, and if necessary, the aromatic vinyl-based monomer includes an unsaturated nitrile-based monomer such as vinyl cyanide, an unsaturated carboxylic acid anhydride, N -Resins obtained by copolymerizing other monomers such as substituted maleimides. These monomers may be used alone or in combination of two or more.

Styrenic resins include acrylonitrile-styrene copolymer, acrylonitrile-α-methylstyrene copolymer, acrylonitrile-styrene-N-phenylmaleimide copolymer, acrylonitrile-styrene-α-methylstyrene-N-phenylmaleimide copolymer. Coalescing, styrene-N-phenylmaleimide copolymers are particularly preferred.

The ratio of the aromatic vinyl monomer unit contained in the styrene resin is preferably 20 to 100% by mass in the monomer mixture (100% by mass) used for producing the styrene resin, and is preferably 30 to 90 mass. % is more preferred, and 50 to 80% by mass is particularly preferred. If the proportion of the aromatic vinyl-based monomer is at least the above lower limit, the resulting thermoplastic resin composition will have good moldability.

Further, the proportion of the unsaturated nitrile-based monomer unit contained in the styrene-based resin is preferably 0 to 50% by mass in the monomer mixture (100% by mass) used for producing the styrene-based resin, and 10 to 40% by mass is more preferred. When the proportion of the unsaturated nitrile-based monomer is equal to or less than the above upper limit, discoloration due to heat of the obtained molded article is suppressed.

In addition, the ratio of other monomer units contained in the styrene resin is preferably 55% by mass or less, and 40% by mass or less in the monomer mixture (100% by mass) used when producing the styrene resin. More preferred. If the ratio of other monomers is equal to or less than the above upper limit, the impact resistance and appearance of the resulting molded article will be well balanced.

Styrenic resins can be produced by known production methods such as emulsion polymerization, suspension polymerization and continuous bulk polymerization.

In the thermoplastic resin composition of the present invention, the thermoplastic resin (B) is a graft copolymer other than the acrylic rubber graft copolymer (A) (hereinafter referred to as the acrylic rubber graft copolymer (A) A graft copolymer other than the above is referred to as a "graft copolymer (B)").
The rubber-like polymer used for the graft copolymer (B) (hereinafter, this rubber-like polymer is referred to as "rubber-like polymer (b)") contains an acrylic acid ester-based monomer unit as an essential component. is preferred.

Examples of acrylic acid ester-based monomers constituting the rubbery polymer (b) include acrylic acid ester-based monomers constituting the rubbery polymer (a) contained in the acrylic rubber-based graft copolymer (A) of the present invention. Examples of monomers include those exemplified. Acrylic acid ester-based monomers can be used alone or in combination of two or more.

The content of the acrylic acid ester-based monomer unit is preferably 75% by mass or more, more preferably 85% by mass or more, and particularly preferably 95% by mass or more based on 100% by mass of the rubbery polymer (b). If the content of the acrylic acid ester-based monomer unit is less than the above lower limit, the resulting thermoplastic resin composition may deteriorate in any of weather resistance, impact resistance, rigidity, and appearance.

In addition, the rubbery polymer (b) may contain polyfunctional monomeric units in addition to the acrylic acid ester-based monomeric units. Examples of the polyfunctional monomer include those exemplified as the polyfunctional monomer used for the rubbery polymer (a). A polyfunctional monomer can be used individually or in combination of 2 or more types.

The content of the polyfunctional monomer units in the rubbery polymer (b) is preferably 3 parts by mass or less, more preferably 2 parts by mass or less, with respect to 100 parts by mass of the acrylic acid ester-based monomer units. Part by weight or less is particularly preferred, while 0.05 parts by weight or more is preferred, 0.1 parts by weight or more is more preferred, and 0.15 parts by weight or more is particularly preferred. If the content of the polyfunctional monomer units in the rubbery polymer (b) exceeds the above upper limit, the impact resistance of the resulting thermoplastic resin composition may decrease. , the appearance may deteriorate.

In addition, the rubbery polymer (b) may contain other monomeric units copolymerizable with the acrylic acid ester-based monomer, if necessary. Other monomers copolymerizable with acrylic acid ester monomers include those exemplified as other monomers used in the rubbery polymer (a), and the other monomers may be used alone or Two or more kinds can be used in combination.

When the rubber-like polymer (b) contains other monomer units copolymerizable with the acrylic acid ester-based monomer, the content thereof in the rubber-like polymer (b) is 25% by mass or less, Furthermore, it is preferably 15% by mass or less, particularly preferably 5% by mass or less. If the content of the other monomer unit exceeds the above upper limit, any one of weather resistance, impact resistance, rigidity and appearance of the obtained thermoplastic resin composition may be deteriorated.

Furthermore, the rubbery polymer (b) used in the graft copolymer (B) is a rubbery polymer containing acrylic acid ester-based monomer units and monomer units other than acrylic acid ester-based monomer units. It is also possible to use a composite rubber with a rubbery polymer composed of Examples of the rubber-like polymer composed of monomer units other than acrylic acid ester-based monomer units include rubbers composed of monomer units other than acrylic acid ester-based monomers exemplified in the rubber-like polymer (a). high-quality polymers. The same applies to the method of obtaining a composite rubber of a rubber-like polymer containing acrylic acid ester-based monomer units and a rubber-like polymer composed of monomer units other than acrylic acid ester-based monomer units. A known method such as a method of polymerizing an acrylic ester-based monomer in the presence of a rubber-like polymer composed of a monomer unit other than an acrylic ester-based monomer unit can be used.

The rubbery polymer (b) is also preferably produced by emulsion polymerization of the above-described monomer mixture in the same manner as the rubbery polymer (a).

As the polymerization initiator used in emulsion polymerization, a redox initiator in which an oxidizing agent and a reducing agent are combined is preferable. Thermally decomposable initiators such as peroxides and azo initiators are industrially disadvantageous because they require a large amount of initiator or require polymerization at a high temperature when adjusting the polymerization rate. be. When a redox initiator is used, the polymerization rate can be adjusted by adjusting the amounts of metal ions as catalysts, oxidizing agents, and reducing agents.

The volume average particle size of the rubbery polymer (b) used in the graft copolymer (B) is preferably larger than 300 nm, more preferably 400 nm or more, while it is preferably 600 nm or less, more preferably 550 nm or less, and 500 nm or less. is particularly preferred. If the volume average particle size of the rubbery polymer (b) is within the above range, the resulting thermoplastic resin composition can maintain good impact strength and appearance.

The graft copolymer (B) is obtained by graft polymerizing a vinyl monomer in the presence of the rubbery polymer (b).
As this vinyl-based monomer, the same vinyl-based monomer as used in the acrylic rubber-based graft copolymer (A) can be used. The same is true for

The graft copolymer (B) can be produced using known production methods such as emulsion polymerization and continuous polymerization. Among these, the emulsion polymerization method is particularly preferred. As the emulsifier, initiator, chain transfer agent and the like used in the emulsion polymerization method, known ones can be used in the same manner as those used in the production of the acrylic rubber graft copolymer (A).

The recovery of the graft copolymer (B) from the latex of the graft copolymer (B) can be carried out in the same manner as the recovery method of the acrylic rubber-based graft copolymer (A) described above.

As described above, the recovery operation may be performed after the acrylic rubber graft copolymer (A) latex, the graft copolymer (B), and, if necessary, another polymer latex are mixed in advance.

The graft copolymer (B) has a content of the rubbery polymer (b) of 10 to 90 parts by mass, particularly 20 to 80 parts by mass, particularly 30 to 30 parts by mass, based on 100 parts by mass of the graft copolymer (B). It is preferably 70 parts by mass. If the content of the rubbery polymer (b) is at least the above lower limit, the resulting thermoplastic resin composition will have higher impact resistance, and if the content of the rubbery polymer (b) is below the above upper limit. The resulting thermoplastic resin composition can maintain a good appearance.

The graft ratio of the graft copolymer (B) is preferably 30-90%, particularly preferably 35-70%. A good appearance can be maintained when the graft ratio of the graft copolymer (B) is within the above range. The graft ratio of the graft copolymer (B) is determined by the method described in the Examples section below.

Further, the acetone-soluble portion of the graft copolymer (B) preferably has a reduced viscosity of 0.40 to 1.00 g/dL, particularly 0.50 to 0.80 g/dL. If the reduced viscosity of the acetone-soluble portion of the graft copolymer (B) is at least the above lower limit, the impact strength will be higher, and if it is below the above upper limit, good appearance and moldability can be maintained. The reduced viscosity of the acetone-soluble portion of the graft copolymer (B) is determined by the method described in the Examples section below.

<Resin component>
The thermoplastic resin composition of the present invention essentially contains the acrylic rubber-based graft copolymer (A) described above as a resin component, and optionally contains another thermoplastic resin (B). is.

When the thermoplastic resin composition of the present invention contains another thermoplastic resin (B), the content of the other thermoplastic resin (B) is relative to 100 parts by mass of the resin component in the thermoplastic resin composition of the present invention. 20 to 95 parts by mass is preferable, 25 to 95 parts by mass is more preferable, and 25 to 90 parts by mass is particularly preferable. By mixing and using another thermoplastic resin (B) with the acrylic rubber graft copolymer (A), the weather resistance, impact resistance, chemical resistance, heat resistance, and molding properties of the thermoplastic resin (B) can be improved. However, if the blending amount of the other thermoplastic resin (B) is too large, the effects of the acrylic rubber graft copolymer (A) of the present invention cannot be sufficiently obtained. Sometimes. If the blending amount of the other thermoplastic resin (B) is equal to or less than the above upper limit, the effect of the acrylic rubber-based graft copolymer (A) of the present invention can be fully exhibited, and good appearance can be maintained. .

Further, when the thermoplastic resin composition of the present invention contains a graft copolymer (B) other than the acrylic rubber-based graft copolymer (A), the graft copolymer (B) in the thermoplastic resin composition of the present invention ) is less than 30 parts by mass in a total of 100 parts by mass of the acrylic rubber-based graft copolymer (A) and the thermoplastic resin (B), which are resin components in the thermoplastic resin composition. It is preferably not more than 25 parts by weight, especially not more than 23 parts by weight, for example 10 to 21 parts by weight.
Since the thermoplastic resin composition of the present invention contains the above-described graft copolymer (B) other than the acrylic rubber-based graft copolymer (A), the resulting thermoplastic resin composition achieves both impact strength and appearance properties. However, if the content is too large, the appearance of the resulting molded product is deteriorated.

The total amount of the rubbery polymer contained in the thermoplastic resin composition of the present invention is preferably 5 to 35 parts by mass, more preferably 5 to 30 parts by mass, with respect to 100 parts by mass of the resin component in the thermoplastic resin composition. is more preferable. When the content of the rubbery polymer in the thermoplastic resin composition is at least the above lower limit, the resulting thermoplastic resin composition has higher impact resistance, and when the content of the rubbery polymer is at most the above upper limit. If there is, the good appearance and fluidity of the resulting thermoplastic resin composition can be maintained.

<Other ingredients>
The thermoplastic resin composition of the present invention may optionally contain coloring agents such as pigments and dyes, heat stabilizers, light stabilizers, reinforcing agents, fillers, flame retardants, foaming agents, lubricants, plasticizers, and electrifying agents. Inhibitors, processing aids, and the like may also be included.

<Method for producing thermoplastic resin composition>
The thermoplastic resin composition of the present invention can be prepared, for example, by mixing the acrylic rubber graft copolymer (A) and optionally other thermoplastic resin (B) and other components in a V-type blender, Henschel mixer, or the like. It is produced by mixing in a mixing device and melt-kneading the mixture obtained by the mixing device. For the melt-kneading, kneaders such as single-screw or twin-screw extruders, Banbury mixers, heating kneaders, and rolls are used.

[Thermoplastic resin molding]
The thermoplastic resin molded article of the present invention obtained by molding the thermoplastic resin composition of the present invention can be used for various purposes.

Examples of methods for molding the thermoplastic resin composition of the present invention include injection molding, extrusion molding, blow molding, compression molding, calendar molding, and inflation molding.

The thermoplastic resin composition of the present invention can also be used as a material for forming a coating layer on substrates made of other resins, metals, and the like.
In this case, other resins as constituent materials of the substrate forming the coating layer of the thermoplastic resin composition of the present invention include, for example, the other thermoplastic resins (B) described above, ABS resins and high-impact polystyrene. rubber-modified thermoplastic resin such as system resin (HIPS); thermosetting resin such as phenol resin and melamine resin;

By coating and molding the thermoplastic resin composition of the present invention onto a base material made of these other resins or metals, it is possible to impart weather resistance and design properties such as good appearance.

Such thermoplastic resin molded articles of the present invention can be used in various applications. For example, for industrial applications, vehicle parts, especially various exterior and interior parts that are used without painting, building material parts such as wall materials and window frames, household appliances such as tableware, toys, vacuum cleaner housings, television housings, air conditioner housings, etc. It is suitably used for parts, interior members, ship members, and electric device housings such as communication device housings, laptop computer housings, portable terminal housings, and liquid crystal projector housings.

EXAMPLES The present invention will be described in more detail with reference to examples below, but the scope of the present invention is not limited by these examples. "Parts" in the following examples are based on mass unless otherwise specified.

[Measurement of rubber polymer and acrylic rubber graft copolymer]
The physical properties and the like of the rubbery polymer and the acrylic rubber graft copolymer were measured by the following methods.

<Solid content>
The solid content of the latex was obtained by weighing 1 g of latex accurately, evaporating the volatile matter at 200° C. for 20 minutes, weighing the residue, and using the following formula.

<Polymerization conversion rate>
The polymerization conversion rate was obtained by measuring the solid content and using the following formula.

<Volume average particle size>
Nikkiso Co., Ltd. dynamic light scattering type particle size/particle size distribution measuring device Nanotrac UPA-EX150 is used. The volume-average particle size was determined by a light scattering method.

<Ratio of acetone solubles>
500 ml of methanol was added to 3.0 g of the graft copolymer, and after stirring at room temperature for 4 hours, methanol-soluble components (non-polymer components) were extracted. Subsequently, the mass of the methanol-insoluble matter obtained by separating the methanol-insoluble matter (polymer component) with a glass filter and drying was measured. Add 80 ml of acetone to this and allow to stand at room temperature for 15 hours, then centrifuge at 30000 rpm for 60 minutes. The mass of the acetone-soluble matter obtained by this was measured.
The acetone-soluble content ratio in the methanol-insoluble content was calculated by the following formula.

<Reduced viscosity>
The reduced viscosity of the acetone-soluble matter in the graft copolymer was obtained by taking the acetone-soluble matter separated by the measurement of the ratio of the acetone-soluble matter as a 0.2 g/dl concentration N,N-dimethylformamide solution, It was measured at 25° C. using an Ubbelohde viscometer.

<Graft rate>
1 g of the graft copolymer is added to 80 ml of acetone and heated under reflux at 65 to 70° C. for 3 hours, and the resulting suspended acetone solution is centrifuged at 14,000 rpm for 30 minutes in a centrifuge to precipitate. A component (acetone-insoluble matter) and an acetone solution (acetone-soluble matter) were separated. The precipitated component (acetone-insoluble matter) was dried, its mass (Y (g)) was measured, and the graft ratio was calculated by the following formula.

<Volume of toluene swollen body>
2 g of a graft copolymer obtained by sieving coarse particles with a 20-mesh sieve and toluene so that the total volume is 50 ml are added to a 50-ml Messlinder, and the graft copolymer is allowed to stand at 23° C. for 24 hours. The volume of the combined swollen body was measured visually.

<Bulk density>
The bulk density of the graft copolymer was measured according to the JIS-K-6720 standard.

[Synthesis Example 1: Production of acid group-containing copolymer latex (K)]
In a reactor equipped with reagent injection vessels, cooling tubes, jacket heaters and agitation,
Deionized water: 200 parts Potassium oleate: 2 parts Sodium dioctylsulfosuccinate: 4 parts Ferrous sulfate heptahydrate: 0.003 parts Disodium ethylenediaminetetraacetate: 0.009 parts Sodium formaldehyde sulfoxylate: 0.3 parts The parts were charged under nitrogen flow and heated to 60°C. After reaching 60°C,
A mixture of n-butyl acrylate: 85 parts, methacrylic acid: 15 parts, and cumene hydroperoxide: 0.5 parts was continuously added dropwise over 120 minutes. After the completion of the dropwise addition, the acid group-containing copolymer having a solid content of 33%, a polymerization conversion rate of 96%, and a volume average particle diameter of 150 nm was further aged at 60° C. for 2 hours. A latex (K) was obtained.

[Synthesis Example 2: Production of rubbery polymer latex (a-1)]
In a reactor equipped with reagent injection vessels, cooling tubes, jacket heaters and agitation,
Deionized water: 295 parts Dipotassium alkenyl succinate: 0.62 parts n-Butyl acrylate: 70 parts Allyl methacrylate: 0.62 parts 1,3-butylene dimethacrylate: 0.05 parts t-butyl hydroperoxide: 0.05 part of the solution was charged while stirring, and after the inside of the reactor was replaced with nitrogen, the contents were heated. At an internal temperature of 55°C,
Sodium formaldehyde sulfoxylate: 0.09 parts Ferrous sulfate heptahydrate: 0.00015 parts Disodium ethylenediaminetetraacetate: 0.00045 parts Deionized water: An aqueous solution consisting of 36 parts is added to initiate polymerization. rice field. After the heat of polymerization was confirmed, the jacket temperature was raised to 75° C., and the polymerization was continued until the heat of polymerization was no longer confirmed, and was held for 30 minutes. The resulting rubbery polymer had a polymerization conversion rate of 99% and a volume average particle size of 110 nm.

continue,
Dipotassium alkenyl succinate: 0.2 parts Sodium formaldehyde sulfoxylate: 0.042 parts Ferrous sulfate heptahydrate: 0.002 parts Disodium ethylenediaminetetraacetate: 0.006 parts Deionized water: 44 parts After adding an aqueous solution and controlling the internal temperature to 70°C,
A mixture of n-butyl acrylate: 30 parts allyl methacrylate: 2.16 parts 1,3-butylene dimethacrylate: 0.03 parts t-butyl hydroperoxide: 0.03 parts was added dropwise over 60 minutes, After completion of the dropwise addition, the liquid temperature was maintained at 70° C. for 30 minutes to obtain a rubbery polymer latex (a-1) having a polymerization conversion rate of 92% and a volume average particle diameter of the rubbery polymer of 160 nm.

[Synthesis Example 3: Production of rubbery polymer latex (a-2)]
In a reactor equipped with reagent injection vessels, cooling tubes, jacket heaters and agitation,
Deionized water: 376 parts Dipotassium alkenyl succinate: 1.45 parts n-Butyl acrylate: 100 parts Allyl methacrylate: 1.2 parts 1,3-butylene dimethacrylate: 0.1 parts t-butyl hydroperoxide: 0.252 parts of the reaction mixture was charged while stirring, and after the inside of the reactor was replaced with nitrogen, the contents were heated. At an internal temperature of 55°C,
Sodium formaldehyde sulfoxylate: 0.09 parts Ferrous sulfate heptahydrate: 0.00015 parts Disodium ethylenediaminetetraacetate: 0.00045 parts Deionized water: An aqueous solution consisting of 30 parts is added to initiate polymerization. rice field. After the heat of polymerization was confirmed, the jacket temperature was raised to 75° C., and the polymerization was continued until the heat of polymerization was no longer confirmed, and was held for 30 minutes. The resulting rubbery polymer had a polymerization conversion rate of 99% and a volume average particle size of 100 nm.

1.2 parts of a 5% by mass sodium pyrophosphate aqueous solution as a solid content was added thereto, and the jacket temperature was controlled so that the internal temperature was 70°C.
Subsequently, at an internal temperature of 70°C, 3 parts of the acid group-containing copolymer latex (K) was added as a solid content, and the internal temperature was maintained at 70°C while stirring for 30 minutes to enlarge the rubber. A rubbery polymer latex (a-2) having a combined volume average particle size of 280 nm was obtained.

[Synthesis Example 4: Production of rubbery polymer latex (x-1)]
In a reactor equipped with a reagent injection vessel, cooling tubes, a jacket heater and a stirring device,
Deionized water: 200 parts Sodium alkylbenzenesulfonate: 5.4 parts n-Butyl acrylate: 10 parts Triallyl isocyanurate: 0.05 parts Cumene hydroperoxide: 0.08 parts was replaced with nitrogen, and the contents were heated. At an internal temperature of 70°C,
An aqueous solution consisting of sodium formaldehyde sulfoxylate: 0.12 parts ferrous sulfate heptahydrate: 0.008 parts disodium ethylenediaminetetraacetate: 0.016 parts deionized water: 5 parts was added to initiate polymerization. . After the heat of polymerization was confirmed, the jacket temperature was set to 60° C., and the polymerization was continued until the heat of polymerization was no longer confirmed.

then
n-butyl acrylate: 99.5 parts triallyl isocyanurate: 0.5 parts cumene hydroperoxide: a mixture of 0.8 parts at 1.8 l/hour,
Sodium alkylbenzenesulfonate: 5.2 parts Deionized water: 115 parts of an aqueous solution at 2.4 l/h,
Sodium formaldehyde sulfoxylate: 0.12 parts Ferrous sulfate heptahydrate: 0.008 parts Disodium ethylenediaminetetraacetate: 0.016 parts Deionized water: An aqueous solution consisting of 5 parts was added at 100 ml/hour over 10 hours. Continuous polymerization was carried out at a polymerization temperature of 70° C. to obtain a rubbery polymer latex (x-1) having a solid content of 43% by mass and a volume average particle size of the rubbery polymer of 150 nm.

[Synthesis Example 5: Production of rubbery polymer latex (x-2)]
In a reactor equipped with a reagent injection vessel, cooling tubes, a jacket heater and a stirring device,
Deionized water: 200 parts Sodium alkylbenzenesulfonate: 2.4 parts n-butyl acrylate: 10 parts Triallyl isocyanurate: 0.05 parts Cumene hydroperoxide: 0.02 parts was replaced with nitrogen, and the contents were heated. At an internal temperature of 60°C,
An aqueous solution consisting of sodium formaldehyde sulfoxylate: 0.09 parts ferrous sulfate heptahydrate: 0.006 parts disodium ethylenediaminetetraacetate: 0.012 parts deionized water: 5 parts was added to initiate polymerization. . After the heat of polymerization was confirmed, the jacket temperature was set to 60° C., and the polymerization was continued until the heat of polymerization was no longer confirmed.

then
n-butyl acrylate: 99.5 parts triallyl isocyanurate: 0.5 parts cumene hydroperoxide: 0.2 parts of a mixed solution at 1.8 l /
Sodium alkylbenzenesulfonate: 2.5 parts Deionized water: 115 parts of an aqueous solution at 2.4 l/h,
Sodium formaldehyde sulfoxylate: 0.09 parts Ferrous sulfate heptahydrate: 0.006 parts Disodium ethylenediaminetetraacetate: 0.012 parts Deionized water: An aqueous solution consisting of 5 parts was added at 100 ml/hour over 10 hours. Continuous polymerization was carried out at a polymerization temperature of 60° C. to obtain a rubbery polymer latex (x-2) having a solid content of 43% by mass and a volume average particle size of the rubbery polymer of 260 nm.

[Example 1: Production of graft copolymer (A-1)]
A reactor equipped with reagent injection vessels, cooling tubes, jacket heaters and agitation equipment,
Deionized water (including water in rubbery polymer latex): 230 parts Rubbery polymer latex (a-1): 50 parts (as solid content)
Dipotassium alkenyl succinate: 0.1 part Sodium formaldehyde sulfoxylate: 0.45 parts were charged, and after the inside of the reactor was sufficiently replaced with nitrogen, the inside temperature was raised to 65°C while stirring.
then
A mixture of acrylonitrile: 15 parts, styrene: 35 parts, and t-butyl hydroperoxide: 0.3 parts was added dropwise over 120 minutes while the temperature was raised to 85°C.
After completion of dropping, the temperature was maintained at 80° C. for 30 minutes and then cooled to obtain a latex of graft copolymer (A-1).
Next, 100 parts of a 2.0% sulfuric acid aqueous solution is heated to 80° C., and while stirring the aqueous solution, 100 parts of the graft copolymer (A-1) latex is gradually added dropwise to the aqueous solution to obtain a graft copolymer ( A-1) was solidified, and the temperature was raised to 95° C. and held for 10 minutes.
The solidified product was then dehydrated, washed and dried to obtain a powdery graft copolymer (A-1).
The resulting graft copolymer (A-1) had an acetone-soluble content of 8%, a graft ratio of 83%, a reduced viscosity of the acetone-soluble content of 0.48 g/dl, and a volume of the toluene swollen product of 18 ml. The density was 0.53 g/cm ³ .

[Example 2: Production of graft copolymer (A-2)]
A powdery graft copolymer (A-2) was obtained in the same manner as in Example 1, except that the rubbery polymer latex (a-1) was changed to the rubbery polymer latex (a-2).
The resulting graft copolymer (A-2) had an acetone-soluble content of 12%, a graft ratio of 74%, a reduced viscosity of the acetone-soluble content of 0.66 g/dl, and a volume of the toluene swollen product of 24 ml. The density was 0.50 g/cm ³ .

[Comparative Example 1: Production of graft copolymer (X-1)]
In a reactor equipped with a reagent injection vessel, cooling tubes, a jacket heater and a stirring device,
Deionized water (including water in rubbery polymer latex): 180 parts Rubbery polymer latex (x-1): 45 parts (as solid content)
was added, and after raising the liquid temperature inside the reactor to 60°C,
sodium formaldehyde sulfoxylate: 0.22 parts ferrous sulfate heptahydrate: 0.004 parts disodium ethylenediaminetetraacetate: 0.02 parts deionized water: an aqueous solution consisting of 10 parts,
Acrylonitrile: 14 parts Styrene: 41 parts Cumene hydroperoxide: A mixture of 0.24 parts was added dropwise over 120 minutes, and
Sodium alkylbenzene sulfonate: 1.0 parts Deionized water: 10 parts of an aqueous solution was added dropwise over 150 minutes for polymerization. After completion of the dropwise addition, the mixture was stirred for 60 minutes while maintaining the internal temperature at 60° C., and then cooled to obtain a graft copolymer (B-1) latex.
Next, 150 parts of a 1.5% by mass calcium chloride aqueous solution is heated to 75° C., and while stirring the aqueous solution, 100 parts of the graft copolymer (X-1) latex is gradually added dropwise to the aqueous solution to perform graft copolymerization. The coalescence (X-1) was solidified, and the temperature was raised to 90° C. and held for 5 minutes. The solidified product was then dehydrated, washed and dried to obtain a powdery graft copolymer (X-1).
The obtained graft copolymer (X-1) had an acetone-soluble content of 30%, a graft ratio of 67%, a reduced viscosity of the acetone-soluble content of 0.71 g/dl, and a volume of the toluene swollen product of 6 ml. The density was 0.38 g/cm ³ .

[Comparative Example 2: Production of graft copolymer (X-2)]
Using rubbery polymer latex (x-2) instead of rubbery polymer latex (x-1), using 60 parts (as a solid content), using 13 parts of acrylonitrile, and using styrene A powdery graft copolymer (X-2) was obtained in the same manner as in Comparative Example 1, except that the amount was changed to 27 parts.
The resulting graft copolymer (X-2) had an acetone-soluble content of 23%, a graft ratio of 35%, a reduced viscosity of the acetone-soluble content of 0.67 g/dl, and a volume of the toluene swollen product of 38 ml. The density was 0.29 g/cm ³ .
Table 1 shows the analysis results of the acrylic rubber graft copolymers (A-1) and (A-2) and the acrylic rubber graft copolymers (X-1) and (X-2). In Table 1, the volume average particle size of the rubbery polymer used for each acrylic rubber graft copolymer is described as the rubber particle size.
Table 1 also shows the analysis results of the graft copolymer (B-1) other than the acrylic rubber-based graft copolymer (A) produced in Synthesis Example 6 described later.

[Synthesis Example 6: Production of graft copolymer (B-1) other than acrylic rubber-based graft copolymer (A)]
<Production of rubbery polymer latex (b-1)>
(First row)
In a reactor equipped with reagent injection vessels, cooling tubes, jacket heaters and agitation,
Deionized water: 290 parts Dipotassium alkenyl succinate: 0.96 parts n-Butyl acrylate: 80 parts Allyl methacrylate: 1 part After purging with nitrogen, the contents were heated. At an internal temperature of 55°C,
Sodium formaldehyde sulfoxylate: 0.36 parts Ferrous sulfate heptahydrate: 0.0002 parts Disodium ethylenediaminetetraacetate: 0.0006 parts Deionized water: An aqueous solution consisting of 10 parts is added to initiate polymerization. rice field. After the heat of polymerization was confirmed, the jacket temperature was set to 75° C., and the polymerization was continued until the heat of polymerization was no longer confirmed, and was further held for 1 hour. The volume average particle size of the resulting rubbery polymer was 100 nm.
1.2 parts of a 5% by mass sodium pyrophosphate aqueous solution was added thereto as a solid content, and the jacket temperature was controlled so that the internal temperature was 70°C.
At an internal temperature of 70° C., 3.2 parts of the acid group-containing copolymer latex (K) as a solid content was added, and the mixture was stirred for 30 minutes while maintaining the internal temperature of 70° C. to enlarge the mixture. The volume average particle size after enlargement was 415 nm.

(Second row)
Then, at an internal temperature of 70°C,
Sodium formaldehyde sulfoxylate: 0.054 parts Ferrous sulfate heptahydrate: 0.002 parts Disodium ethylenediaminetetraacetate: 0.006 parts Deionized water: Add an aqueous solution consisting of 80 parts followed by acrylic acid n. A mixture of -butyl: 20 parts, allyl methacrylate: 0.24 parts, and t-butyl hydroperoxide: 0.03 parts was added dropwise over 40 minutes. After completion of dropping, the mixture was maintained at a temperature of 70° C. for 1 hour and then cooled to obtain a rubbery polymer latex (b-1) having a volume average particle size of 440 nm.

<Production of graft copolymer (B-1)>
A graft copolymer other than the acrylic rubber-based graft copolymer (A) was prepared in the same manner as in Example 1, except that the rubbery polymer latex (a-1) was changed to the rubbery polymer latex (b-1). (B-1) was obtained.
The resulting graft copolymer (B-1) had an acetone-soluble content of 20%, a graft ratio of 60%, a reduced viscosity of the acetone-soluble content of 0.76 g/dl, and a volume of the toluene swollen product of 25 ml. The density was 0.40 g/cm ³ .

[Synthesis Example 7: Production of copolymers (B-2) and (B-3)]
A copolymer (B-2) composed of 28% by mass of acrylonitrile and 72% by mass of styrene and having a reduced viscosity of 0.61 g/dl was obtained by a known suspension polymerization method.
Further, a copolymer (B-3) composed of 32% by mass of acrylonitrile and 68% by mass of styrene and having a reduced viscosity of 0.59 g/dl was obtained.

As the thermoplastic resin (B-4), a polycarbonate resin (Iupilon S-3000 (viscosity average molecular weight (Mv): 21,000), manufactured by Mitsubishi Engineering-Plastics Co., Ltd.) was used.

[Examples 3 to 10, Comparative Examples 3 to 6: Production and evaluation of thermoplastic resin compositions]
Acrylic rubber graft copolymer (A) or (X) and other thermoplastic resin (B) are used in the formulations shown in Tables 2 and 3, and 0 ethylene bisstearic acid amide is added to 100 parts of these in total. .5 parts and 1 part of carbon black #960 (manufactured by Mitsubishi Chemical Corporation) as a coloring agent were added, mixed using a Henschel mixer, and the mixture was set to a barrel temperature of 220 ° C. 28 mm twin shaft manufactured by Nippon Steel Co., Ltd. It was shaped with an extruder (model: TEX28V) to produce thermoplastic resin pellets.

This thermoplastic resin pellet is molded at 235 ° C. with a 55-ton injection molding machine (model: IS55FP) manufactured by Toshiba Machine Co., Ltd., and 10 × 80 necessary for measuring Charpy impact strength, flexural modulus and deflection temperature under load. A x4 mm strip test piece was prepared. Further, it was molded at 240° C. with a 55-ton injection molding machine (model: IS55FP) manufactured by Toshiba Machine Co., Ltd. to prepare a strip test piece of 150×10×2 mm required for chemical resistance measurement. Further, using a 75-ton injection molding machine (model: JSW-75EIIP) manufactured by Nippon Steel Co., Ltd., a cylinder temperature of 240° C. and an injection speed of 10 g/sec. (low speed) and 40 g/sec. (high speed) to prepare a flat molded plate of 100 mm×100 mm×2 mm required for measuring glossiness, color development and sharpness. A molded plate for thermal stability measurement was prepared as follows.
The following measurements were performed on the obtained thermoplastic resin pellets, strip test piece and flat molded plate.
Tables 2 and 3 show the measurement results. Tables 2 and 3 also show the rubber content of each thermoplastic resin composition.

<Impact resistance>
Charpy impact strength was measured for a V-notched test piece that had been left in an atmosphere of 23° C. for 12 hours or more by a method based on ISO 179.

<Heat resistance>
Deflection temperature under load was measured at 1.83 MPa, 4 mm, flatwise method according to ISO test method 75.

<Liquidity>
The melt volume rate was measured using thermoplastic resin pellets under conditions of 220° C. and a load of 10 kg in accordance with ISO1133.

<Rigidity>
The flexural modulus at a temperature of 23° C. was measured according to ISO178.

<Chemical resistance>
A 150 x 10 x 2 mm strip specimen was clamped along a bending foam test jig with a surface of gradual curvature. Next, the test piece was coated with a chemical solution and left in an environment of 23° C. for 48 hours. Then, the presence or absence of crazes and cracks in the test piece was confirmed, and the critical strain [%] was obtained from the curvature of the test jig. Alcohol: ethanol (Wako Pure Chemical Industries, Ltd.) and surfactant: Noigen ET-190 (Kao Corporation) were used as chemicals.

<Glossiness>
Using a digital goniophotometer (model: UGV-5D) manufactured by Suga Shikenki Co., Ltd., an incident angle of 60° and a reflection angle of 60 were measured for a flat molded plate of 100 mm × 100 mm × 2 mm obtained under low-speed and high-speed conditions. The glossiness was obtained from the reflectance at °.

<color development>
The 100 mm×100 mm×2 mm flat plate formed under the low speed and high speed conditions was measured for lightness (L*) using a colorimeter manufactured by Minolta (Model: CM-508D). A smaller value of L* indicates better color developability.
Further, the difference (absolute value) in lightness (L*) of these flat molded plates was used as an index of molding condition dependence of color development.

<Vividness>
A 100 mm × 100 mm × 2 mm flat molded plate obtained under low speed and high speed conditions was measured using an image clarity measuring instrument (model: ICM-IDP) manufactured by Suga Test Instruments Co., Ltd., with a reflection angle of 60° and an optical comb. The sharpness at a width of 1 mm was measured. A larger numerical value indicates better image sharpness. Also, the dependency of sharpness on molding conditions was calculated from the following formula.

<Thermal stability>
Cylinder temperature: 280°C, injection speed: 40 g/sec. A flat plate of 100 mm×100 mm×2 mm was obtained under the following conditions. Subsequently, after weighing the resin, the molding operation was interrupted and the resin was retained in the injection molding machine for 20 minutes. After that, the molding operation was resumed, and the molded plate obtained in the 3rd to 5th shots and the molded plate obtained without retention were measured with a digital goniophotometer (model: UGV-) manufactured by Suga Shikenki Co., Ltd. 5D), the glossiness was measured from the reflectance at an incident angle of 60° and a reflection angle of 60°, and the gloss retention rate was calculated from the following formula and used as an index of thermal stability. The higher the numerical value, the better the thermal stability.

Table 2 reveals the following.
In Comparative Examples 3 and 4, the acetone-soluble content ratio, graft ratio, volume and bulk density of the toluene-swelled product of the acrylic rubber graft copolymer (X) are outside the scope of the present invention. Impact resistance, chemical resistance, color development of the molded product, sharpness and heat stability, and for Comparative Example 4, the chemical resistance, color development of the molded product, sharpness and heat stability are determined by the acrylic rubber graft It is inferior to Examples 3 to 5 using copolymer (A-1) or (A-2).
On the other hand, the thermoplastic resin compositions of Examples 3 to 5 have impact resistance, rigidity, heat resistance, moldability (fluidity), chemical resistance, glossiness of molded products, color development, sharpness and It has good properties such as excellent thermal stability and less dependence on molding conditions for appearance performance.

Moreover, Table 3 shows the following.
In Comparative Example 5, the acrylic rubber graft copolymer (X-1) had an acetone-soluble content ratio, graft ratio, volume and bulk density of the toluene swollen material outside the scope of the present invention. It is inferior to Examples 6 to 10 using the acrylic rubber graft copolymer (A-1) in terms of image quality and sharpness.
Further, in Comparative Example 6, since the acrylic rubber-based graft copolymer (A) is not used, the glossiness, color development and sharpness of the molded article are inferior.
In contrast, the thermoplastic resin compositions of Examples 6 to 10 are excellent in impact resistance, rigidity, heat resistance, moldability (fluidity), glossiness, color development, and sharpness of molded products, and have excellent appearance. It has good properties such as little dependence on molding conditions for performance.

[Examples 11 to 12, Comparative Examples 7 and 8: Production and evaluation of thermoplastic resin compositions]
The acrylic rubber graft copolymer (A) or (X) and the thermoplastic resin (B) are used in the formulation shown in Table 4, and 0.5 parts of paraffin wax is added to 100 parts of these in total, and as a coloring agent 1 part of carbon black #960 (manufactured by Mitsubishi Chemical Corporation) was added and mixed using a Henschel mixer, and the mixture was heated to a barrel temperature of 250 ° C. with a devolatilizing twin-screw extruder (TEX28V) manufactured by Nippon Steel Corporation. It was shaped to produce thermoplastic resin pellets.

This thermoplastic resin pellet is molded at 250 ° C. with a 55-ton injection molding machine (model: IS55FP) manufactured by Toshiba Machine Co., Ltd., and 10 × 80 necessary for measuring Charpy impact strength, flexural modulus and deflection temperature under load. A x4 mm strip test piece was prepared. In addition, using a 150-ton injection molding machine SG150-SYCAP/MIV manufactured by Sumitomo Heavy Industries, Ltd., the cylinder temperature was 260° C. and the injection speed was 50 mm/sec. (low speed) and 100 mm/sec. Each was molded at (high speed) to prepare a flat molded plate of 100 mm x 150 mm x 3 mm required for measuring glossiness, color development and sharpness.

Impact resistance, heat resistance, fluidity, rigidity, glossiness, color development, and sharpness of the obtained thermoplastic resin pellets, strip test pieces and flat plate moldings were measured in the same manner as in Example 3. The measurement results are shown in Table 4 together with the rubber content of each thermoplastic resin composition.

Table 4 reveals the following.
In Comparative Examples 7 and 8, the acetone-soluble content ratio, graft ratio, volume and bulk density of the toluene-swollen body of the acrylic rubber graft copolymer (X-1) were outside the scope of the present invention. are inferior to those of Examples 11 and 12 using the acrylic rubber graft copolymer (A-1).
In contrast, the thermoplastic resin compositions of Examples 11 and 12 are excellent in impact resistance, rigidity, heat resistance, moldability (fluidity), glossiness, color development, and sharpness of molded products, and have excellent appearance. It has good properties such as little dependence on molding conditions for performance.

Claims (6)

A graft copolymer obtained by graft-polymerizing a vinyl-based monomer in the presence of a rubber-like polymer (a) containing an acrylic acid alkyl ester-based monomer unit and a polyfunctional monomer unit,
The content of the alkyl acrylate monomer units in 100% by mass of the rubbery polymer (a) is 75% by mass or more, and the content of the polyfunctional monomer units is equal to the alkyl acrylate monomer units 1.0 to 3.3 parts by mass per 100 parts by mass of the body unit,
The content of the rubbery polymer (a) in 100 parts by mass of the acrylic rubber-based graft copolymer (A) is 10 to 90 parts by mass,
The vinyl-based monomer is a monomer mixture containing an aromatic vinyl-based monomer and an unsaturated nitrile-based monomer,
The ratio of the aromatic vinyl monomer in 100% by weight of the monomer mixture is 20 to 97% by weight, and the ratio of the unsaturated nitrile monomer is 3 to 50% by weight,
An acrylic rubber-based graft copolymer (A) characterized by satisfying all of the following physical properties (1) to (5).
(1) The rubbery polymer (a) has a volume average particle size of 100 to 300 nm.
(2) The acetone-soluble content in the methanol-insoluble content of the graft copolymer is 5 to 20% by mass.
(3) The graft ratio of the graft copolymer is 70 to 120%.
(4) 2 g of the graft copolymer whose coarse particles have been sieved through a 20-mesh sieve is placed in a 50 ml messslinder, toluene is added so that the total volume is 50 ml, and the mixture is allowed to stand at 23° C. for 24 hours. The volume of the swollen graft copolymer is 10-35 ml.
(5) The bulk density of the graft copolymer measured according to JIS-K-6720 standard is 0.40 to 0.60 g/cm ³ . 2. The acrylic rubber graft copolymer (A) according to claim 1, wherein the acrylic acid alkyl ester monomer is n-butyl acrylate. A thermoplastic resin composition comprising the acrylic rubber-based graft copolymer (A) according to claim 1 or 2 . 95 parts by mass of a thermoplastic resin (B) other than the acrylic rubber graft copolymer (A) in a total of 100 parts by mass of the acrylic rubber graft copolymer (A) and the thermoplastic resin (B) 4. The thermoplastic resin composition of claim 3 , comprising: The thermoplastic resin (B) does not contain a graft copolymer other than the acrylic rubber graft copolymer (A), or the thermoplastic resin (B) is other than the acrylic rubber graft copolymer (A). 4. The content of the graft copolymer is less than 30 parts by mass with respect to a total of 100 parts by mass of the acrylic rubber graft copolymer (A) and the thermoplastic resin (B) The thermoplastic resin composition according to . A thermoplastic resin molded product obtained by molding the thermoplastic resin composition according to any one of claims 3 to 5 .