JP2023005526A - Thermoplastic resin composition - Google Patents

Abstract

To provide a thermoplastic resin composition which can achieve both impact resistance and color development property in a good balance.SOLUTION: A thermoplastic resin composition comprises: a graft copolymer resin (A) obtained by graft polymerization of a vinyl-based monomer containing a vinyl cyanide-based monomer and an aromatic vinyl-based monomer to a rubbery polymer, where a predetermined requirement with regard to a free resin contained in the graft copolymer resin (A) is satisfied; a graft copolymer resin (B) obtained by graft polymerization of a vinyl-based monomer containing an aromatic vinyl-based monomer to a rubbery polymer containing a constitutional unit derived from (meth)acrylate, where an average particle size of the rubbery polymer in the graft copolymer resin (B) is 50 nm to 150 nm; and a copolymer (C) obtained by copolymerization of a vinyl monomer of an aromatic vinyl-based monomer and a vinyl cyanide-based monomer.SELECTED DRAWING: None

Description

The present invention relates to thermoplastic resin compositions.

Rubber-reinforced thermoplastic resin compositions containing acrylic rubber-based graft copolymers are generally excellent in moldability, impact resistance, weather resistance, chemical resistance, thermal stability, etc., and are widely used in electrical and electronic fields. It is used in a wide range of fields such as the equipment field and the OA equipment field. Among them, in recent years, application to applications requiring a high-quality appearance has been studied, and there is a demand for a rubber-reinforced thermoplastic resin composition excellent in color development.

For example, in Patent Document 1, according to a thermoplastic resin composition containing an acrylic rubber graft copolymer having predetermined requirements, impact resistance, chemical resistance, surface appearance (gloss and color development) of molded products and excellent thermal stability during high-temperature molding.

JP 2020-029545 A

As a result of studies by the present inventors, it has become clear that there is room for improvement in conventional rubber-reinforced thermoplastic resin compositions such as those disclosed in Patent Document 1 with respect to both impact resistance and color development.

Accordingly, an object of the present invention is to provide a rubber-reinforced thermoplastic resin composition capable of achieving both impact resistance and color developability in a well-balanced manner.

As a result of intensive studies to solve the above problems, the present inventors have found the inventions described in [1] to [5] below.
[1] A graft copolymer resin (A) obtained by graft-polymerizing a rubber-like polymer with a vinyl-based monomer containing a vinyl cyanide-based monomer and an aromatic vinyl-based monomer, The free resin contained in the graft copolymer resin (A) contains 10 to 35 masses of constituent units derived from (meth)acrylic acid alkyl ester having an alkyl group having 4 or more carbon atoms, based on the total amount of the free resin. % and satisfying at least one of the following requirements (1) and (2);
A graft copolymer resin (B) obtained by graft-polymerizing a vinyl-based monomer containing an aromatic vinyl-based monomer to a rubber-like polymer containing a structural unit derived from a (meth)acrylic acid ester, a graft copolymer resin (B) in which the rubber-like polymer in the graft copolymer resin (B) has an average particle size of 50 nm to 150 nm;
a copolymer (C) obtained by copolymerizing a vinyl-based monomer containing an aromatic vinyl-based monomer and a vinyl cyanide-based monomer;
A thermoplastic resin composition comprising:
(1) The rubber-like polymer in the graft copolymer resin (A) contains a structural unit derived from a (meth)acrylic acid alkyl ester in which the alkyl group has 4 or more carbon atoms.
(2) The vinyl-based monomer in the graft copolymer resin (A) further contains a (meth)acrylic acid alkyl ester having an alkyl group with 4 or more carbon atoms.
[2] The vinyl-based monomer in the graft copolymer resin (A) is, based on the total amount of the vinyl-based monomer, 10 to 10 to 10 (meth)acrylic acid alkyl esters in which the alkyl group has 4 or more carbon atoms. The thermoplastic resin composition according to [1], containing 30% by mass.
[3] The rubber-like polymer in the graft copolymer resin (A) contains a structural unit derived from a (meth)acrylic acid alkyl ester having an alkyl group having 4 or more carbon atoms, based on the total amount of the rubber-like polymer. The thermoplastic resin composition according to [1] or [2], containing 50% by mass or more.
[4] The thermoplastic resin composition according to any one of [1] to [3], wherein the rubber-like polymer in the graft copolymer resin (A) has a gel content of 75 to 90%.
[5] Any one of Claims 1 to 4, wherein the vinyl-based monomer in the copolymer (C) contains 28% by mass or more of the vinyl cyanide-based monomer based on the total amount of the vinyl-based monomer. 1. The thermoplastic resin composition according to item 1.

According to the rubber-reinforced thermoplastic resin composition of the present invention, it is possible to achieve both impact resistance and color developability in a well-balanced manner.

Preferred embodiments of the present invention are described below. In this specification, "(meth)acrylic acid ester" indicates acrylic acid ester or methacrylic acid ester, and the same applies to similar expressions such as "(meth)acrylate".

The thermoplastic resin composition of the present embodiment contains a graft copolymer resin (A), a graft copolymer resin (B), and a copolymer (C). Each component will be described below.

[Graft copolymer resin (A)]
The graft copolymer resin (A) is obtained by graft-polymerizing a vinyl-based monomer to a rubber-like polymer. The graft copolymer resin (A) includes a graft copolymer obtained by graft-polymerizing a vinyl-based monomer to a rubber-like polymer, as well as a free resin obtained by polymerizing vinyl-based monomers with each other. It may contain monomers and the like. The free resin contained in the graft copolymer resin (A) may be the one produced during the production of the rubber-like polymer, or the unreacted monomer during the production of the rubber-like polymer. It may also be a free resin produced by reaction of the polymer during graft polymerization.

Examples of the rubber-like polymer include butadiene-based rubber-like polymers such as polybutadiene, styrene-butadiene copolymers, and acrylonitrile-butadiene copolymers; ethylene-propylene copolymers, ethylene-propylene-diene copolymers, and the like. ethylene-propylene-based rubber-like polymer; (meth)acrylic acid ester-based monomers such as methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate (Meth)acrylic rubber-like polymer containing a polymer as a main component; Silicone rubber-like polymer; Composite rubber-like polymer of butadiene-based rubbery polymer/(meth)acrylic rubber-like polymer; Silicone-based rubbery polymer Polymer/(meth)acrylic rubber-like polymer composite rubber-like polymer, chlorinated polyethylene rubber, and the like. These can be used individually by 1 type or in combination of 2 or more types.

Among these rubber-like polymers, a (meth)acrylic rubber-like polymer is preferable from the viewpoint of further improving weather resistance, and a (meth)acrylic acid alkyl ester-derived polymer having an alkyl group having 4 or more carbon atoms is A (meth)acrylic rubber-like polymer containing structural units is preferred. The content of the structural unit derived from the (meth)acrylic acid alkyl ester whose alkyl group has 4 or more carbon atoms in the (meth)acrylic rubber-like polymer is 50% by mass or more from the viewpoint of further improving the weather resistance. It is preferably at least 60% by mass, and even more preferably at least 70% by mass. The upper limit of the content of the structural unit derived from the (meth)acrylic acid alkyl ester having 4 or more carbon atoms in the alkyl group in the (meth)acrylic rubber-like polymer is not particularly limited, but may be, for example, 95% by mass or less. can be done.

Examples of (meth)acrylic acid alkyl esters in which the alkyl group has 4 or more carbon atoms include butyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and (meth)acrylic acid. octyl and the like. Although the upper limit of the carbon number of the alkyl group in the (meth)acrylic acid alkyl ester having 4 or more carbon atoms in the alkyl group is not particularly limited, it can be, for example, 15 or less or 10 or less.

The acrylic rubber-like polymer may be crosslinked with a crosslinking agent. Examples of cross-linking agents include divinylbenzene, allyl (meth) acrylate, ethylene glycol di (meth) acrylate, diallyl phthalate, dicyclopentadiene di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol hexa(meth) ) acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, triallyl cyanurate, triallyl isocyanurate and the like.

The content of structural units derived from the cross-linking agent in the rubber-like polymer cross-linked with the cross-linking agent can be, for example, 0.1% by mass to 5% by mass.

The acrylic rubber-like polymer contains structural units derived from monomers other than the above monomers, such as structural units derived from conjugated diene monomers, aromatic vinyl monomers, and vinyl cyanide monomers. may have

Conjugated diene-based monomers include 1,3-butadiene, isoprene, 2-chloro-1,3-butadiene, chloroprene, 2-methyl-1,3-butadiene, 2,3-dimethyl-1,3-butadiene etc., and one or more of them can be used.

Examples of aromatic vinyl monomers include styrene, α-methylstyrene, paramethylstyrene, bromostyrene and the like, and one or more of them can be used.

Examples of vinyl cyanide monomers include acrylonitrile, methacrylonitrile, ethacrylonitrile, fumaronitrile and the like, and one or more of them can be used.

The content of structural units derived from the conjugated diene-based monomer, the aromatic vinyl-based monomer, or the vinyl cyanide-based monomer in the rubber-like polymer is each independently, for example, 30% by mass or less, more preferably 20% by mass. % by mass or less, more preferably 10% by mass or less. When the rubber-like polymer contains these structural units, the lower limit of the content is not particularly limited, but can be, for example, 1% by mass or more independently.

The rubber-like polymer can be produced by a conventionally known method such as emulsion polymerization. In emulsion polymerization, a polymerization initiator, an emulsifier, a polymerization modifier, etc. may be used.

Examples of the polymerization initiator include water-soluble polymerization initiators such as potassium persulfate, sodium persulfate and ammonium persulfate, cumene hydroperoxide, benzoyl peroxide, t-butyl hydroperoxide, acetyl peroxide, diisopropylbenzene hydroperoxide, Oil-soluble polymerization initiators such as peroxides and 1,1,3,3-tetramethylbutyl hydroperoxide are included.

Examples of the emulsifier include carboxylates, sulfates, sulfonates, and the like. Specific examples of preferably used emulsifiers include potassium oleate, dipotassium alkenylsuccinate, sodium rosinate, potassium rosinate, sodium dodecylbenzenesulfonate and the like.

Examples of the polymerization modifier include alkylmercaptans such as n-dodecylmercaptan and t-dodecylmercaptan.

From the viewpoint of improving the impact resistance of the graft copolymer resin (A), the rubber-like polymer preferably has a gel content of 75 to 90%. The gel content of the rubber-like polymer is measured, for example, by the method described in Examples below.

The average particle size of the rubber-like polymer is not particularly limited, but can be, for example, more than 100 nm and less than or equal to 800 nm, preferably more than 150 nm and less than or equal to 500 nm. In this specification, the average particle size of the rubber polymer can be measured by the dynamic light scattering method based on the photon correlation method, for example, according to JIS Z8826.

The graft copolymer resin (A) preferably contains 10 to 90% by mass, more preferably 30 to 80% by mass, of the rubber-like polymer from the viewpoint of the balance between impact resistance and color development. It is more preferable to contain up to 70% by mass.

Vinyl monomers used in the graft polymerization include vinyl cyanide monomers and aromatic vinyl monomers. The vinyl-based monomer preferably further contains a (meth)acrylic acid alkyl ester having an alkyl group with 4 or more carbon atoms. As the vinyl cyanide-based monomer, the aromatic vinyl-based monomer, and the (meth)acrylic acid alkyl ester having an alkyl group having 4 or more carbon atoms, the same ones as described above can be preferably used.

The content of the vinyl cyanide monomer used in the graft polymerization is, for example, 10 to 40% by mass, preferably 15 to 35% by mass, more preferably 20 to 30% by mass, based on the total amount of vinyl monomers. %. The content of the aromatic vinyl monomer used in the graft polymerization is, for example, 40 to 80% by mass, preferably 45 to 75% by mass, more preferably 50 to 70% by mass, based on the total amount of vinyl monomers. %.

From the viewpoint of further improving chemical resistance, the content of the (meth)acrylic acid alkyl ester having 4 or more carbon atoms in the alkyl group in the vinyl-based monomer used in the graft polymerization is the total amount of the vinyl-based monomer. Based on, it is preferably 10 to 30% by mass.

The free resin contained in the graft copolymer resin (A) is a structural unit derived from a (meth)acrylic acid alkyl ester having 10 to 35% by mass of the alkyl group having 4 or more carbon atoms based on the total amount of the free resin. including. Chemical resistance is improved by satisfying the requirement.

The graft copolymer resin (A) can be produced by a conventionally known method, and for example, polymerization methods such as emulsion polymerization, suspension polymerization and bulk polymerization can be used. When the emulsion polymerization method is used, a latex of the graft copolymer resin (A) can be obtained by graft-polymerizing the vinyl-based monomer onto the rubber-like polymer. The latex of the graft copolymer resin (A) is coagulated by a known method, and the powder of the graft copolymer resin (A) can be obtained through washing, dehydration and drying steps.

The term "free resin" as used herein refers to a resin that can be separated from the graft copolymer resin (A) by the following procedures (a) and (b).
(a) Acetone is added to the graft copolymer resin (A), and then the insoluble matter and dissolved liquid are separated by centrifugation or the like. This separates the graft copolymer as an insoluble matter.
(b) The resulting solution is reprecipitated using a poor solvent such as methanol, and the precipitate is collected by filtration or the like. As a result, unreacted vinyl-based monomers and the like are separated to the solution side. By drying the remaining precipitate, the free resin to be analyzed is obtained.

The types of structural units contained in the free resin can be determined by applying a known technique such as pyrolysis gas chromatography. In addition, the content of structural units contained in the free resin, particularly the content of structural units derived from vinyl cyanide monomers, aromatic vinyl monomers and (meth)acrylic acid alkyl esters, is CHN described in Examples. The content of each structural unit can be obtained and calculated by applying analysis, oxygen analysis, or the like.

The free resin content in the graft copolymer resin (A) can be adjusted, for example, by the following methods (a) to (c).
(a) The content of the (meth)acrylic acid alkyl ester whose alkyl group has 4 or more carbon atoms in the vinyl-based monomer used for graft polymerization is adjusted to, for example, 10 to 30% by mass.
(a) For example, rosin acid or a derivative thereof is used as an emulsifier used in the production of the rubber-like polymer.
(c) adding a polymerization modifier such as t-dodecyl mercaptan during the production of the rubber-like polymer;

The content of the graft copolymer resin (A) in the thermoplastic resin composition is, for example, 5 to 60% by mass, preferably 10 to 50% by mass, more preferably 15 to 40%, based on the total amount of the thermoplastic resin composition. % by mass.

[Graft copolymer resin (B)]
The graft copolymer resin (B) is obtained by graft-polymerizing a vinyl-based monomer containing an aromatic vinyl-based monomer onto a rubber-like polymer containing a structural unit derived from a (meth)acrylic acid ester. The graft copolymer resin (B) includes a graft copolymer obtained by graft-polymerizing a vinyl-based monomer to a rubber-like polymer, as well as a free resin obtained by polymerizing vinyl-based monomers with each other. It may contain monomers and the like.

The graft copolymer resin (B) can conceptually overlap with the graft copolymer resin (A), but they must be present in the thermoplastic resin composition as independent components. That is, even when a graft copolymer resin satisfying the requirements of the graft copolymer resin (A) and the graft copolymer resin (B) is used, the thermoplastic resin composition further contains the graft copolymer resin ( A) or a graft copolymer resin (B) must be included.

Examples of the rubber-like polymer include (meth)acrylate monomers such as methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate. (Meth)acrylic rubber-like polymer composed mainly of polyether; Butadiene rubber-like polymer/(meth)acrylic rubber-like polymer composite rubber-like polymer; Silicone rubber-like polymer/(meth)acrylic and composite rubber-like polymers of rubber-like polymers. These can be used individually by 1 type or in combination of 2 or more types.

Among these rubber-like polymers, a (meth)acrylic rubber-like polymer is preferable from the viewpoint of further improving weather resistance, and a (meth)acrylic rubber containing a structural unit derived from a (meth)acrylic acid alkyl ester. A (meth)acrylic rubber-like polymer containing a structural unit derived from a (meth)acrylic acid alkyl ester whose alkyl group has 4 or more carbon atoms is more preferable. The content of structural units derived from (meth)acrylic acid alkyl esters (especially (meth)acrylic acid alkyl esters in which the number of carbon atoms in the alkyl group is 4 or more) in the (meth)acrylic rubber-like polymer increases the weather resistance. From the viewpoint of improvement, the content is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more. The upper limit of the content of structural units derived from (meth)acrylic acid alkyl ester in the (meth)acrylic rubber-like polymer is not particularly limited. 95% by mass or less of the structural unit derived from the (meth)acrylic acid alkyl ester may be used.

Examples of (meth)acrylic acid alkyl esters include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, hexyl (meth)acrylate, and (meth)acrylate. 2-ethylhexyl acrylate, octyl (meth)acrylate and the like.

The rubber-like polymer may be crosslinked with a crosslinking agent. Examples of cross-linking agents include divinylbenzene, allyl (meth) acrylate, ethylene glycol di (meth) acrylate, diallyl phthalate, dicyclopentadiene di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol hexa(meth) ) acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, triallyl cyanurate, triallyl isocyanurate and the like.

The content of structural units derived from the cross-linking agent in the rubber-like polymer cross-linked with the cross-linking agent can be, for example, 0.1% by mass to 5% by mass.

The rubber-like polymer is a structural unit derived from a monomer other than the (meth)acrylic acid alkyl ester described above, such as a conjugated diene monomer, an aromatic vinyl monomer, or a vinyl cyanide monomer. may have a structural unit of As the conjugated diene-based monomer, the aromatic vinyl-based monomer, and the vinyl cyanide-based monomer, those exemplified in the graft copolymer resin (A) can be applied.

The content of the constituent units derived from the conjugated diene-based monomer, the aromatic vinyl-based monomer, or the vinyl cyanide-based monomer in the rubber-like polymer is each independently, for example, 30% by mass or less, more preferably It can be 20% by mass or less, more preferably 10% by mass or less. When the rubber-like polymer contains these structural units, the lower limit of the content is not particularly limited, but can be, for example, 1% by mass or more independently.

The rubber-like polymer can be produced by a conventionally known method such as emulsion polymerization, as in the case of the graft copolymer resin (A).

The average particle size of the rubber-like polymer is 50 nm to 150 nm, preferably 55 nm to 135 nm, more preferably 60 nm to 120 nm. Thereby, the impact resistance and the color developability can be improved in a well-balanced manner.

From the viewpoint of impact resistance balance, the graft copolymer resin (B) preferably contains 10 to 90% by mass, more preferably 30 to 80% by mass, more preferably 40 to 70% by mass of the rubbery polymer. % by mass is more preferable.

The vinyl-based monomers used in the graft polymerization include aromatic vinyl-based monomers. The vinyl-based monomer preferably further contains a vinyl cyanide-based monomer. As the aromatic vinyl-based monomer and the vinyl cyanide-based monomer, those similar to those described above can be preferably used.

The content of the aromatic vinyl monomer used in the graft polymerization is, for example, 50 to 90% by mass, preferably 55 to 85% by mass, more preferably 60 to 80% by mass, based on the total amount of vinyl monomers. %. The content of the vinyl cyanide monomer used in the graft polymerization is, for example, 10 to 40% by mass, preferably 15 to 35% by mass, more preferably 20 to 30% by mass, based on the total amount of vinyl monomers. %.

The graft copolymer resin (B) can be produced by a conventionally known method in the same manner as the graft copolymer resin (A). A polymerization method such as a polymerization method can be used. When the emulsion polymerization method is used, a latex of the graft copolymer resin (B) can be obtained by graft-polymerizing the vinyl-based monomer onto the rubber-like polymer. The latex of the graft copolymer resin (B) is coagulated by a known method, and the powder of the graft copolymer resin (B) can be obtained through washing, dehydration and drying steps.

The content of the graft copolymer resin (B) in the thermoplastic resin composition is, for example, 0.5 to 40% by mass, preferably 1 to 35% by mass, more preferably 1% by mass, based on the total amount of the thermoplastic resin composition. .5 to 30% by mass.

[Copolymer (C)]
The copolymer (C) is obtained by polymerizing vinyl-based monomers including an aromatic vinyl-based monomer and a vinyl cyanide-based monomer.

As the aromatic vinyl-based monomer and the vinyl cyanide monomer, the same ones as those described above can be preferably used.

The content of the aromatic vinyl monomer in the vinyl monomer is, for example, 50 to 95% by mass, preferably 55 to 90% by mass, more preferably 60 to 85% by mass, based on the total amount of the vinyl monomer. % by mass. The content of the vinyl cyanide monomer in the vinyl monomer is, for example, 5 to 50% by mass, preferably 10 to 45% by mass, more preferably 15 to 40% by mass, based on the total amount of the vinyl monomer. %.

The vinyl-based monomer may further contain a (meth)acrylate monomer and a maleimide-based monomer. As the (meth)acrylic acid ester monomer, those similar to those described above can be preferably used. Examples of maleimide monomers include N-phenylmaleimide and N-cyclohexylmaleimide. These can be used individually by 1 type or in combination of 2 or more types.

When the vinyl-based monomer contains a (meth)acrylic acid ester monomer and/or a maleimide-based monomer, the content thereof independently is, for example, 50% by mass or less, preferably 30% by mass or less, More preferably, it can be 10% by mass or less. Although the lower limit of the content when these monomers are included is not particularly limited, it may be, for example, 1% by mass or more independently of each other.

Specific examples of the copolymer (C) include styrene/acrylonitrile copolymer (AS resin), α-methylstyrene/acrylonitrile copolymer (αMS-ACN resin), methyl methacrylate/acrylonitrile/styrene copolymer ( MAS resin), styrene/N-phenylmaleimide/acrylonitrile copolymer (SA-NPMI resin), and the like.

The copolymer (C) can be obtained by polymerizing the above vinyl monomers by a conventionally known method such as emulsion polymerization. At the time of emulsion polymerization, a polymerization initiator, an emulsifier, a polymerization modifier, etc. may be used in the same manner as in the case of the graft copolymer resin (A). The copolymer (C) can also be powdered in the same manner as the graft copolymer resin (A).

The content of the copolymer (C) in the thermoplastic resin composition is, for example, 40 to 90% by mass, preferably 45 to 85% by mass, more preferably 50 to 80% by mass, based on the total amount of the thermoplastic resin composition. can be

The thermoplastic resin composition of the present embodiment may optionally contain various additives such as known antioxidants, light stabilizers, lubricants, plasticizers, antistatic agents, colorants, flame retardants, matting agents, Fillers, glass fibers and the like can be added as appropriate.

The thermoplastic resin composition of the present embodiment can be obtained in the form of pellets by melt-kneading using a known device such as a Banbury mixer, roll mill, twin-screw extruder, or the like. The thermoplastic resin composition thus obtained can be molded by injection molding, extrusion molding, compression molding, injection compression molding, blow molding, or the like.

Molded articles molded from the thermoplastic resin composition of the present embodiment are excellent in impact resistance, color development, etc., and thus can be suitably applied to vehicle interior and exterior parts, OA equipment, building materials, and the like.

EXAMPLES The present invention will be specifically described below with reference to Examples, but the present invention is not limited to these. In addition, % shown in the examples is based on the mass.

[Production of crosslinked butyl acrylate rubber latex (a-1)]
219 parts by mass of deionized water, 10 parts by mass of styrene, 5.0 parts by mass of butyl acrylate, 0.035 parts by mass of allyl methacrylate, 0.011 parts by mass of t-dodecylmercaptan, and dodecylbenzenesulfone were added to a nitrogen-substituted glass reactor. 0.15 parts by mass of sodium sulfate (in terms of solid content) and 0.15 parts by mass of potassium persulfate were charged and reacted at 65° C. for 1 hour.
Then, 0.75 parts by mass of sodium dodecylbenzenesulfonate (solid (converted to minutes) was continuously added over 3 hours. After dropping, the mixture was held for 3.5 hours to obtain a crosslinked butyl acrylate rubber latex (a-1).

<Method for measuring gel content>
The gel content of the crosslinked butyl acrylate rubber latex (a-1) was measured by the following method.
After drying the crosslinked butyl acrylate rubber latex (a-1), 0.25 g of the latex was immersed in 100 ml of toluene for 48 hours, filtered through a 300-mesh wire mesh, and the filtration residue was completely dried. The weight (W0) after drying before immersion in toluene and the weight (W1) of the completely dried filtration residue were measured, and the gel content was calculated from the following formula. As a result, the gel content of the crosslinked butyl acrylate rubber latex (a-1) was 85%.
(W1/W0) x 100 = gel content [%]

[Production of graft copolymer resin (a-2)]
A glass reactor purged with nitrogen was charged with 50 parts by mass of the crosslinked butyl acrylate rubber latex (a-1) (in terms of solid content) and purged with nitrogen. After purging with nitrogen, the inside of the tank was heated to 60° C., and 0.40 parts by mass of glucose, 0.025 parts by mass of anhydrous sodium pyrophosphate and 0.001 parts by mass of ferrous sulfate were added to 9.0 parts by mass of deionized water. An aqueous solution dissolved in parts by mass was added. After reaching 65 ° C., a mixture of 11.7 parts by mass of acrylonitrile (ACN), 33.3 parts by mass of styrene (STY), 5 parts by mass of butyl acrylate, and 0.1 parts by mass of t-dodecyl mercaptan and 16 parts by mass of deionized water An emulsifier aqueous solution prepared by dissolving 1.0 parts by mass of potassium oleate and 0.28 parts by mass of t-butyl hydroperoxide (in terms of solid content) in parts by mass was continuously added dropwise over 6 hours. After dropping, the mixture was held for 2 hours to obtain a graft copolymer resin (a-2).

[Production of graft copolymer resin powder (A)]
When deionized water and 100 parts by mass of the graft copolymer resin (a-2) in terms of solid content were completely added to a single coagulation tank equipped with a stirring blade, the slurry concentration was 18%. I planted it to be. After that, 4.0 parts by mass of magnesium sulfate was added and the temperature was raised to 85°C. After reaching 85° C., 100 parts by mass of graft copolymer resin (a-2) and 1.3 parts by mass of disproportionated potassium rosinate were added. After the addition, the mixture was heated to 95°C and held for 1 minute, washed with water, dehydrated, and dried in a hot air dryer at 90°C for 14 hours to obtain a graft copolymer resin powder (A).

<Free resin composition analysis>
Free resin composition analysis was performed on the graft copolymer resin powder (A). Specifically, for a measurement sample prepared by the following method, the amount of acrylonitrile was calculated from the amount of nitrogen by the CHN analysis described below, and the amount of butyl acrylate was calculated from the amount of oxygen by the oxygen (O) analysis described below. The total amount of butyl acrylate was taken as 100%, and the remainder after subtracting the calculated amounts of acrylonitrile and butyl acrylate was calculated as the amount of styrene. The amount of butyl acrylate in the free resin was calculated based on the amounts of acrylonitrile, butyl acrylate and styrene. As a result, the amount of butyl acrylate in the free resin in the graft copolymer resin powder (A) was 14.0%.

(Preparation of measurement sample)
4.0 g of graft copolymer resin powder was weighed, 50 mL of acetone was added, and the mixture was allowed to stand for 16 hours. After concentrating the solution, it was dissolved in acetone, reprecipitated with methanol, filtered, and the filtrate was dried to obtain a solid. This solid matter was used as a measurement sample.

(CHN analysis conditions)
Apparatus: JM10 manufactured by J Science Lab Co., Ltd.
Standard samples: acetanilide, phenacetin, antipyrine Temperature: 1000°C

(Oxygen analysis conditions)
Apparatus: MO-20 manufactured by Yanako Analysis Industry Co., Ltd.
Standard sample: Cholesterol Temperature: 1000°C

[Production of crosslinked butyl acrylate rubber latex (b-1)]
206 parts by mass of deionized water, 100 parts by mass of butyl acrylate, 0.64 parts by mass of allyl methacrylate, 3.0 parts by mass of dipotassium alkenylsuccinate (in terms of solid content), t-butyl hydroperoxide, and 0.010 parts by mass of oxide (in terms of solid content) was charged, and the inside of the tank was heated to 40°C.
When the temperature inside the tank reached 40°C, 0.020 parts by mass of formaldehyde sodium sulfoxylate, 0.010 parts by mass of ethylenediaminetetraacetic acid tetrasodium salt and 0.001 parts by mass of ferrous sulfate were added to 10.0 parts by mass of deionized water. An aqueous solution dissolved in parts was added.
After the addition, the mixture was held for 5.0 hours to obtain a crosslinked butyl acrylate rubber latex (b-1).

[Production of crosslinked butyl acrylate rubber latex (b-2)]
206 parts by mass of deionized water, 3.0 parts by mass of dipotassium alkenylsuccinate (converted to solid content), and 0.050 parts by mass of t-butyl hydroperoxide (converted to solid content) were charged into a glass reactor purged with nitrogen, and the inside of the tank was was raised to 40°C.
When the temperature inside the tank reached 40°C, 0.050 parts by mass of formaldehyde sodium sulfoxylate, 0.010 parts by mass of ethylenediaminetetraacetic acid tetrasodium salt and 0.001 parts by mass of ferrous sulfate were added to 10.0 parts by mass of deionized water. An aqueous solution dissolved in parts was added.
After the addition, a mixed solution of 100 parts by mass of butyl acrylate and 0.64 parts by mass of allyl methacrylate was continuously added over 3 hours. After the addition, the mixture was held for 3.5 hours to obtain a crosslinked butyl acrylate rubber latex (b-2).

[Production of graft copolymer resin (b-3)]
A glass reactor was charged with 50 parts by mass of crosslinked butyl acrylate rubber latex (b-1) (in terms of solid content), and the reactor was purged with nitrogen. After purging with nitrogen, the inside of the tank was heated to 60° C., and an aqueous solution of 0.80 parts by mass of glucose dissolved in 10.0 parts by mass of deionized water was added. After reaching 65°C, a mixture of 12.5 parts by mass of acrylonitrile (ACN), 37.5 parts by mass of styrene (STY), and 0.05 parts by mass of t-dodecylmercaptan and 10 parts by mass of deionized water were added with dipotassium alkenyl succinate. An emulsifier aqueous solution in which 0.60 parts by mass and 0.28 parts by mass of t-butyl hydroperoxide (calculated as solid content) were dissolved was continuously added dropwise over 6 hours. After dropping, the mixture was held for 2 hours to obtain a graft copolymer resin (b-3).

[Production of graft copolymer resin (b-4)]
A glass reactor was charged with 70 parts by mass of crosslinked butyl acrylate rubber latex (b-2) (in terms of solid content), and the reactor was purged with nitrogen. After purging with nitrogen, the inside of the tank was heated to 60° C., and an aqueous solution of 0.24 parts by mass of glucose dissolved in 10.0 parts by mass of deionized water was added. After reaching 65 ° C., dipotassium alkenyl succinate was added to a mixture of 7.5 parts by mass of acrylonitrile (ACN), 22.5 parts by mass of styrene (STY), and 0.060 parts by mass of t-dodecyl mercaptan and 10 parts by mass of deionized water. An emulsifier aqueous solution in which 0.36 parts by mass and 0.17 parts by mass of t-butyl hydroperoxide (calculated as solid content) were dissolved was continuously added dropwise over 4 hours. After dropping, the mixture was held for 2 hours to obtain a graft copolymer resin (b-4).

[Production of graft copolymer resin powder (B-1)]
When the total amount of deionized water and 100 parts by mass of the graft copolymer resin (b-3) in terms of solid content were added to a single coagulation tank equipped with a stirring blade, the slurry concentration was 18%. I planted it to be. After that, 4.0 parts by mass of magnesium sulfate was added and the temperature was raised to 70°C. After reaching 70° C., 100 parts by mass of graft copolymer resin (b-3) was added. After the addition, the mixture was heated to 90°C and held for 1 minute, washed with water, dehydrated, and dried in a hot air dryer at 90°C for 14 hours to obtain a graft copolymer resin powder (B-1).

[Production of graft copolymer resin powder (B-2)]
When 100 parts by mass of deionized water in terms of solid content of the graft copolymer resin (b-4) was completely added to the single-tank coagulation tank equipped with a stirring blade, the slurry concentration reached 18%. I planted it to be. After that, 4.0 parts by mass of magnesium sulfate was added and the temperature was raised to 70°C. After reaching 70° C., 100 parts by mass of graft copolymer resin (b-4) was added. After the addition, the mixture was heated to 90°C and held for 1 minute, washed with water, dehydrated, and dried in a hot air dryer at 90°C for 14 hours to obtain a graft copolymer resin powder (B-2).

[Production of copolymer (C)]
A copolymer (C) comprising 67.3 parts by mass of styrene and 32.7 parts by mass of acrylonitrile was obtained by a known bulk polymerization method. As a result of measuring the reduced viscosity of the obtained copolymer (C) by the following method, the reduced viscosity was 0.52 dl/g.
After dissolving in N,N-dimethylformamide to obtain a solution with a concentration of 0.4 g/100 ml, the reduced viscosity is determined from the flow-down time measured at 30° C. using a Canon-Fenske viscosity tube.

[Synthetic resin coloring agent (D)]
Carbon black (manufactured by Sumika Color Co., Ltd. Black PAB-8A3645 Mixture of AS resin and carbon black Carbon black content 45%)

<Measurement of average particle size of crosslinked butyl acrylate rubber latex>
The crosslinked butyl acrylate rubber latex was diluted with water, and the average particle size was measured using FPAR-1000 manufactured by Otsuka Electronics Co., Ltd. Table 1 shows the results.

<Evaluation of thermoplastic resin composition>
Graft copolymer resin powders (A), (B-1) and (B-2), copolymer (C), and coloring agents for synthetic resins were added in the amounts shown in Table 2 (unit: parts by mass). After mixing (D), the mixture was melt-kneaded at 240° C. using a 26 mmφ twin-screw extruder and pelletized to obtain pellets of the thermoplastic resin composition. Various molded articles were molded from the obtained pellets with an injection molding machine set at 250° C., and each measurement and evaluation were performed by the following methods. Table 2 shows the evaluation results.

<Charpy impact strength (NC)>
Various test pieces were molded from the pellets according to ISO294, and the impact resistance (unit: kJ/m ² ) was measured. Specifically, the notched Charpy impact value was measured with a thickness of 4 mm in accordance with ISO179.
Then, impact resistance was evaluated according to the following criteria.
A: 10 kJ/m ² or more B: 4 kJ/m ² or more and less than 10 kJ/m ² C: less than 4 kJ/m ²

<Color development (jet blackness) evaluation>
Using the above pellets, various test pieces were molded with an injection molding machine. As a molding die, a 55 mm × 90 mm × 2.5 mm thick flat plate mold for jet blackness measurement equipped with a mirror surface mold whose mold surface was polished with # 1,500 was used. Molding was performed under molding conditions of a temperature of 60° C. and an injection pressure of 3 MPa.
The jet-blackness of the flat plate mirror surface portion of the obtained molding was measured with CMS-35SPJC2 manufactured by Murakami Color Research Laboratory. A smaller L* value (SCE) indicates better jet-blackness. Good jet-blackness also means excellent color developability when the same amount of the same coloring agent is added.
Then, the color developability (jet-blackness) was evaluated according to the following criteria.
A: L* value less than 5 B: L* value 5 or more

Claims (5)

A graft copolymer resin (A) obtained by graft-polymerizing a rubber-like polymer with a vinyl-based monomer containing a vinyl cyanide-based monomer and an aromatic vinyl-based monomer, The free resin contained in the coalesced resin (A) contains 10 to 35% by mass of a structural unit derived from a (meth)acrylic acid alkyl ester having an alkyl group having 4 or more carbon atoms, based on the total amount of the free resin, and a graft copolymer resin (A) that satisfies at least one of the following requirements (1) and (2);
A graft copolymer resin (B) obtained by graft-polymerizing a vinyl-based monomer containing an aromatic vinyl-based monomer to a rubber-like polymer containing a structural unit derived from a (meth)acrylic acid ester, a graft copolymer resin (B) in which the rubber-like polymer in the graft copolymer resin (B) has an average particle size of 50 nm to 150 nm;
a copolymer (C) obtained by copolymerizing a vinyl-based monomer containing an aromatic vinyl-based monomer and a vinyl cyanide-based monomer;
A thermoplastic resin composition comprising:
(1) The rubber-like polymer in the graft copolymer resin (A) contains a structural unit derived from a (meth)acrylic acid alkyl ester in which the alkyl group has 4 or more carbon atoms.
(2) The vinyl-based monomer in the graft copolymer resin (A) further contains a (meth)acrylic acid alkyl ester having an alkyl group with 4 or more carbon atoms. The vinyl-based monomer in the graft copolymer resin (A) is 10 to 30 masses of a (meth)acrylic acid alkyl ester having an alkyl group having 4 or more carbon atoms, based on the total amount of the vinyl-based monomer. %. The rubber-like polymer in the graft copolymer resin (A) contains 50 mass of structural units derived from a (meth)acrylic acid alkyl ester having an alkyl group having 4 or more carbon atoms, based on the total amount of the rubber-like polymer. % or more, the thermoplastic resin composition according to claim 1 or 2. The thermoplastic resin composition according to any one of claims 1 to 3, wherein the gel content of the rubber-like polymer in the graft copolymer resin (A) is 75 to 90%. Any one of claims 1 to 4, wherein the vinyl-based monomer in the copolymer (C) contains 28% by mass or more of the vinyl cyanide-based monomer based on the total amount of the vinyl-based monomer. The thermoplastic resin composition according to .