JP2023092045A - Core-shell type graft copolymer particle, method for producing the same, and resin composition - Google Patents

Abstract

To provide core-shell type graft copolymer particles which enable formation of a resin composition that is good in both impact resistance and weather resistance by being blended with a thermoplastic resin.SOLUTION: Core-shell type graft copolymer particles contain core particles (A), and a shell layer (B) coating the core particles (A). The core particles (A) contain polyalkyl (meth)acrylate rubber, and a reactive ultraviolet absorber represented by formula (1) is copolymerized with at least a part of the polyalkyl (meth)acrylate rubber. A volume average particle diameter of the core particles (A) is 400-800 nm. A ratio occupied by the core particles (A) in the core-shell type graft copolymer particles is 50-80 wt.%. The shell layer (B) includes a layer (b1) of a copolymer including an aromatic vinyl compound unit and a vinyl cyanide compound unit.SELECTED DRAWING: None

Description

TECHNICAL FIELD The present invention relates to core-shell type graft copolymer particles, a method for producing the same, and a resin composition containing the particles.

ABS resin (acrylonitrile-butadiene-styrene) has excellent rigidity, impact resistance, heat deformation resistance, etc., so it is used for various miscellaneous goods, interior and exterior materials for automobiles, housings for household appliances such as jar rice cookers, microwave ovens, and vacuum cleaners. It is widely used for parts, housings and parts of OA equipment such as telephones and facsimiles, but it has the disadvantage of low weather resistance.

In order to improve the weather resistance of ABS resin, ASA resin (acrylonitrile-styrene- acrylic) have been developed. However, ASA resin has a problem that it is difficult to develop impact resistance as compared with ABS resin.

In Patent Document 1, a graft copolymer obtained by graft-polymerizing an aromatic vinyl monomer, a vinyl cyanide monomer, or an unsaturated acid ester monomer in the presence of crosslinked acrylate-based rubber particles. is blended into an acrylonitrile-styrene resin.

On the other hand, as an additive for acrylic resins, there is known one obtained by copolymerizing a core-shell type graft copolymer with a reactive ultraviolet absorber (see, for example, Patent Document 2).

JP-A-58-222139 WO2015/133153

Blending a graft copolymer containing an acrylic rubber into a thermoplastic resin such as an acrylonitrile-styrene resin can improve the impact resistance of the resin, but further improvement is desired. In addition, an improvement in weather resistance is also required.

In view of the above-mentioned current situation, the present invention provides core-shell type graft copolymer particles capable of forming a resin composition having both good impact resistance and weather resistance by blending with a thermoplastic resin, a method for producing the same, and , to provide a resin composition containing the particles.

The present inventors have found that the above problems can be solved by adopting a specific configuration in acrylic rubber-containing graft copolymer particles to be added to thermoplastic resins such as acrylonitrile-styrene resins, leading to the present invention. rice field.

That is, the present invention provides a core-shell type graft copolymer particle comprising a core particle (A) and a shell layer (B) covering the core particle (A),
The core particle (A) contains a polyalkyl (meth)acrylate rubber,
At least part of the polyalkyl (meth)acrylate rubber is copolymerized with a reactive ultraviolet absorber represented by the following formula (1),
The core particle (A) has a volume average particle diameter of 400 to 800 nm,
The proportion of the core particles (A) in the core-shell type graft copolymer particles is 50 to 80% by weight,
The shell layer (B) relates to core-shell type graft copolymer particles including a copolymer layer (b1) containing aromatic vinyl compound units and vinyl cyanide compound units.

In formula (1), X represents hydrogen or halogen, R ¹ represents hydrogen, a methyl group, or a t-alkyl group having 4 to 6 carbon atoms, and R ² represents a linear or branched represents an alkylene group having 2 to 10 carbon atoms, and R ³ represents hydrogen or a methyl group;
Preferably, the core particle (A) is configured such that the degree of cross-linking on the particle surface is higher than the cross-linking degree on the inside of the particle.
Preferably, the core particle (A) is composed of an inner layer, one or more intermediate layers, and an outer layer,
The outer layer has a higher degree of cross-linking than the inner layer and the intermediate layer.
Preferably, the reactive ultraviolet absorber is copolymerized with the polyalkyl (meth)acrylate rubber of the intermediate layer.
Preferably, the reactive ultraviolet absorber is not copolymerized in the polyalkyl (meth)acrylate rubber of the outer layer.
Preferably, the shell layer (B) further comprises an outer layer (b2) positioned outside the layer (b1),
The outer layer (b2) is formed from a polymer containing aromatic vinyl compound units.
The present invention also provides a method for producing the core-shell type graft copolymer particles,
a step of polymerizing a monomer component containing an alkyl (meth)acrylate and a crosslinkable monomer to form core particles (A) composed of a polyalkyl (meth)acrylate rubber;
In the presence of the core particle (A), a monomer component containing an aromatic vinyl compound and a vinyl cyanide compound is copolymerized to form a shell layer (B), and the core-shell type graft copolymer particle is obtained. It also relates to a manufacturing method, including the step of obtaining.
Preferably, in the step of forming the core particles (A), an inner layer, one or more intermediate layers, and an outer layer are formed by multistage polymerization of a monomer component containing an alkyl (meth)acrylate and a crosslinkable monomer. A core particle (A) composed of is formed.
Furthermore, the present invention provides 100 parts by weight of a thermoplastic resin containing a copolymer containing an aromatic vinyl compound unit and a vinyl cyanide compound unit, and
It also relates to a resin composition containing 10 to 100 parts by weight of the core-shell type graft copolymer particles, or a molded article obtained by molding the resin composition.

According to the present invention, acrylic rubber-containing graft copolymer particles capable of forming a resin composition having both good impact resistance and weather resistance by blending with a thermoplastic resin, a method for producing the same, and A resin composition containing the particles can be provided.

Embodiments of the present invention are described in detail below.
<Core-shell type graft copolymer particles>
A core-shell type graft copolymer particle according to the present disclosure has a core-shell structure including a core particle (A) and a shell layer (B) covering the core particle (A). The core particles (A) refer to rubber particles located inside the core-shell type graft copolymer particles. On the other hand, the shell layer (B) is located on the surface side of the core-shell type graft copolymer particles, refers to a polymer layer covering the surface of the core particles (A), and is also called a graft layer. The shell layer (B) covers the surface of the core particle (A), but is not limited to covering the entire surface of the core particle (A), and covers at least part of the surface of the core particle (A). It should be covered.

<Core particle (A)>
Core particles (A) are made of polyalkyl (meth)acrylate rubber. Here, rubber means a polymer having a crosslinked structure (hereinafter also referred to as a crosslinked polymer). Since the core particles (A) are formed from a crosslinked polymer, impact resistance can be imparted to the thermoplastic resin by blending the core-shell type graft copolymer particles with the thermoplastic resin.

The core particles (A) may contain other rubbers (e.g., siloxane-based rubber, butadiene-based rubber, etc.) in addition to the polyalkyl(meth)acrylate rubber. It is preferably made of rubber only. Specifically, the proportion of the polyalkyl (meth)acrylate rubber in the core particles (A) is preferably 90 to 100% by weight, more preferably 95 to 100% by weight, and particularly preferably 99 to 100% by weight. .

The polyalkyl (meth)acrylate rubber is a crosslinked product obtained by polymerizing a monomer component containing an alkyl (meth)acrylate and a crosslinkable monomer. In addition, "(meth)acryl" collectively describes acryl and methacryl.

The alkyl (meth)acrylate is not particularly limited, but examples include alkyl acrylates such as methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate; methyl methacrylate, ethyl methacrylate , propyl methacrylate, 2-ethylhexyl methacrylate, and lauryl methacrylate. These monomers may be used alone or in combination of two or more.

As the alkyl (meth)acrylate, an acrylic acid alkyl ester is preferable. In the monomer component (excluding the crosslinkable monomer) for forming the polyalkyl (meth)acrylate rubber, the content of the acrylic acid alkyl ester is preferably 50 to 100% by weight, preferably 70 to 100% by weight. 100% by weight is more preferred, 80 to 100% by weight is more preferred, 90 to 100% by weight is even more preferred, and 95 to 100% by weight is particularly preferred.

The number of carbon atoms in the alkyl group of the acrylic acid alkyl ester is preferably 1 to 22 carbon atoms, more preferably 1 to 18 carbon atoms, still more preferably 2 to 12 carbon atoms, and even more preferably 2 to 8 carbon atoms. Butyl acrylate is particularly preferred as the alkyl acrylate.

In view of the low glass transition temperature of the resulting polymer and economic efficiency, it is preferable that 40 to 100% by weight, more preferably 60 to 100% by weight, of butyl acrylate is contained among the monomer components. preferable. Preferred alkyl (meth)acrylates used in combination with butyl acrylate are methyl acrylate, ethyl acrylate and 2-ethylhexyl acrylate.

The monomer component for forming the polyalkyl(meth)acrylate rubber may consist only of the alkyl(meth)acrylate, but the unsaturated bond copolymerizable with the alkyl(meth)acrylate may further contain other monomers having one in one molecule. The other monomer is not particularly limited, but includes, for example, (meth)acrylic monomers other than alkyl (meth)acrylates, aromatic vinyl compounds, vinyl cyanide compounds, and vinyl halides such as vinyl chloride and chloroprene. compounds, vinyl acetate, alkenes such as ethylene and propylene, and the like.

The crosslinkable monomer used for forming the polyalkyl(meth)acrylate rubber is a compound having two or more unsaturated bonds copolymerizable with the alkyl(meth)acrylate in one molecule. be. Although not particularly limited, specific examples include (meth)acrylates having an allyl group such as allyl (meth)acrylate, allylalkyl (meth)acrylate, and allyloxyalkyl (meth)acrylate; Ethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, (poly)ethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di( Polyfunctional (meth)acrylates having two or more (meth)acryloyl groups such as meth)acrylate, polypropylene glycol di(meth)acrylate, butanediol di(meth)acrylate; diallyl phthalate, triallyl cyanurate, triallyl Examples include isocyanurate and divinylbenzene. A crosslinkable monomer may use only 1 type, and may use 2 or more types together. Among them, allyl methacrylate, triallyl isocyanurate, butanediol di(meth)acrylate, and divinylbenzene are preferred, and allyl methacrylate is particularly preferred.

According to the present embodiment, the polyalkyl (meth)acrylate rubber is copolymerized with a reactive ultraviolet absorber represented by the following formula (1) in order to improve the weather resistance of the resin composition. As a result, the weather resistance of the resin composition obtained by blending the core-shell type graft copolymer particles with the thermoplastic resin can be remarkably improved. If the reactive UV absorber is not copolymerized in the core layer (A) and the reactive UV absorber is copolymerized only in the shell layer (B), substantially no improvement in weather resistance can be expected.

The reactive ultraviolet absorber may be copolymerized only in the core layer (A), or may be copolymerized in each of the core layer (A) and the shell layer (B). However, even if the shell layer (B) is copolymerized, the effect of improving weather resistance cannot be expected. Therefore, from the viewpoint of cost reduction, the shell layer (B) is not copolymerized, and only the core layer (A) is copolymerized. preferably.

The reactive ultraviolet absorber may be copolymerized in the entire polyalkyl(meth)acrylate rubber, or may be copolymerized in at least a part of the polyalkyl(meth)acrylate rubber. The form of copolymerization is not particularly limited, and may be either random copolymerization or block copolymerization, but random copolymerization is preferred.

In formula (1), X represents hydrogen or halogen. R ¹ represents hydrogen, a methyl group, or a t-alkyl group having 4 to 6 carbon atoms. R ² represents a linear or branched alkylene group having 2 to 10 carbon atoms, preferably an ethylene group or a propylene group. ^R3 represents hydrogen or a methyl group.

Specific examples of the reactive ultraviolet absorbers include 2-(2′-hydroxy-5′-methacryloyloxyethylphenyl)-2H-benzotriazoles, 2-(2′-hydroxy-5′-acryloyloxy ethylphenyl)-2H-benzotriazole, 2-(2'-hydroxy-5'-methacryloyloxyethylphenyl-2H-benzotriazole, 2-(2'-hydroxy-5'-methacryloyloxyethylphenyl)-5-chloro -2H-benzotriazole, 2-(2'-hydroxy-5'-methacryloyloxypropylphenyl)-2H-benzotriazole, 2-(2'-hydroxy-5'-methacryloyloxyethyl-3'-t-butylphenyl )-2H-benzotriazole, etc. More preferred is 2-(2′-hydroxy-5′-methacryloyloxyethylphenyl)-2H-benzotriazole in terms of cost and handling.

The amount of the reactive ultraviolet absorber used is preferably 0.1 to 10 parts by weight with respect to 100 parts by weight of the core-shell type graft copolymer particles, from the viewpoint of the balance between weather resistance and impact resistance. 3 to 8 parts by weight is more preferred, 0.4 to 5 parts by weight is even more preferred, and 0.5 to 3 parts by weight is particularly preferred.

The ratio of the core particles (A) to the entire core-shell type graft copolymer particles is 50% by weight or more and 80% by weight or less from the viewpoint of impact resistance. The lower limit is preferably 55% by weight or more, more preferably 60% by weight or more, still more preferably 65% by weight or more, and particularly preferably 68% by weight or more. The upper limit is preferably 78% by weight or less, more preferably 75% by weight or less, and even more preferably 73% by weight or less.

From the viewpoint of impact resistance and productivity, the volume average particle diameter of the core particles (A) is 400 nm or more and 800 nm or less. If the particle size is less than 400 nm, the impact resistance becomes insufficient when the core-shell type graft copolymer particles are blended with the thermoplastic resin. On the other hand, if it exceeds 800 nm, the productivity of the core-shell type graft copolymer particles tends to decrease. The lower limit is preferably 430 nm or more, more preferably 450 nm or more, still more preferably 480 nm or more, and particularly preferably 500 nm or more. The upper limit is preferably 750 nm or less, more preferably 700 nm or less, and even more preferably 650 nm or less.

The volume average particle size of the core particles (A) is a value measured by using a particle size measuring device in the state of a latex of polymer particles, as shown in the Examples section. The particle size of the core particles (A) can be controlled by the types and amounts of initiators, reducing agents, emulsifiers, etc. used in the polymerization, the polymerization temperature, the polymerization time, and the like.

From the viewpoint of improving impact resistance, the core particle (A) is preferably configured such that the degree of cross-linking on the surface of the particle is higher than the degree of cross-linking on the inside of the particle. By adopting such a specific configuration for the degree of cross-linking of the core particles (A), it is possible to remarkably improve the impact resistance of the thermoplastic resin by blending the core-shell type graft copolymer particles. The degree of cross-linking refers to the density of the cross-linked structure introduced into the polymer by the cross-linking monomer. The degree of cross-linking can be controlled by adjusting the ratio of the amount of cross-linking monomer to the amount of monomer component (concentration of cross-linking monomer). is expensive.

According to one aspect of this embodiment, the core particle (A) may have a multi-layer structure composed of at least two layers. In this multilayer structure, by adjusting the degree of cross-linking in each layer, the degree of cross-linking on the surface of the core particle (A) can be set higher than the degree of cross-linking on the inside of the core particle (A).
Specifically, the core particle (A) preferably includes at least an inner core layer located inside the particle and an outer core layer located on the surface side of the particle. It is preferable to configure the degree of cross-linking to be higher than that of the core inner layer.

The core particle (A) may have a two-layer structure composed only of the inner core layer and the outer core layer.
However, from the viewpoint of improving impact resistance, the core particle (A) preferably further includes at least one intermediate core layer between the inner core layer and the outer core layer. In this case, it is preferable that the degree of cross-linking of the outer core layer is higher than the degree of cross-linking of the inner core layer and the degree of cross-linking of the core intermediate layer.

Preferably, each of the inner core layer, the intermediate core layer, and the outer core layer consists essentially of the polyalkyl (meth)acrylate rubber. Specifically, the proportion of the polyalkyl (meth)acrylate rubber in each layer is preferably 90 to 100% by weight, more preferably 95 to 100% by weight, and particularly preferably 99 to 100% by weight. The type or amount of monomer components constituting each layer and the type of crosslinkable monomer used in each layer may be the same or different.

The ratio of the amount of the crosslinkable monomer in each layer is preferably selected within the range of 0.01 to 20 parts by weight with respect to 100 parts by weight of the monomer component constituting each layer. The range is more preferably 0.05 to 15 parts by weight, still more preferably 0.08 to 12 parts by weight, and particularly preferably 0.1 to 10 parts by weight.

Specifically for each layer, the ratio of the amount of the crosslinkable monomer in the core inner layer is preferably 0.01 to 3 parts by weight with respect to 100 parts by weight of the monomer component constituting the core inner layer. 0.05 to 2 parts by weight is more preferred, 0.08 to 1 part by weight is more preferred, and 0.1 to 0.5 parts by weight is even more preferred.

It is preferable that the ratio of the crosslinkable monomer amount in the core intermediate layer is larger than the ratio of the crosslinkable monomer amount in the core inner layer and lower than the ratio of the crosslinkable monomer amount in the core outer layer. Specifically, the ratio of the amount of the crosslinkable monomer in the core intermediate layer is preferably 0.05 to 5 parts by weight with respect to 100 parts by weight of the monomer component constituting the core intermediate layer. .1 to 3 parts by weight is more preferred, 0.15 to 2 parts by weight is more preferred, and 0.2 to 1 part by weight is even more preferred.

A plurality of core intermediate layers may be present. In that case, the ratio of the amount of the crosslinkable monomer in the first intermediate layer located closer to the core inner layer (that is, closer to the surface) is the ratio of the amount of the crosslinkable monomer in the first intermediate layer located farther from the core inner layer (that is, closer to the surface). It is preferably less than the ratio of the amount of crosslinkable monomers in the two intermediate layers.

It is preferable that the ratio of the crosslinkable monomer amount in the core outer layer is higher than the ratio of the crosslinkable monomer amount in the core inner layer and the ratio of the crosslinkable monomer amount in the core intermediate layer. Specifically, the ratio of the amount of the crosslinkable monomer in the outer core layer is preferably 0.1 to 20 parts by weight, preferably 1 to 15 parts by weight, with respect to 100 parts by weight of the monomer component constituting the outer core layer. Parts by weight are more preferred, 3 to 12 parts by weight are more preferred, and 5 to 10 parts by weight are more preferred.

The ratio of each layer of the core particle (A) to the entire core-shell type graft copolymer particle is not particularly limited, but from the viewpoint of impact resistance, the total ratio of the inner core layer and the intermediate core layer is 30% by weight. It is preferably 79% by weight or more, more preferably 40% by weight or more and 70% by weight or less, and even more preferably 50% by weight or more and 65% by weight or less. The ratio of the core outer layer is preferably 1% by weight or more and 30% by weight or less, more preferably 2% by weight or more and 20% by weight or less, and even more preferably 3% by weight or more and 10% by weight or less.

The above-described reactive ultraviolet absorber may be copolymerized in one or more of the core inner layer, the core intermediate layer, and the core outer layer. In particular, the reactive ultraviolet absorber is preferably copolymerized with at least the polyalkyl (meth)acrylate rubber of the core intermediate layer, and the polyalkyl (meth) It is preferable that the acrylate rubber and the polyalkyl (meth)acrylate rubber of the core intermediate layer are respectively copolymerized.
On the other hand, it is preferable that the polyalkyl (meth)acrylate rubber of the core outer layer is not copolymerized with the reactive ultraviolet absorber. This is because even if the reactive ultraviolet absorber is copolymerized in the core outer layer, the effect of improving the weather resistance is relatively low.

According to another aspect of this embodiment, the core particle (A) may be configured such that the degree of cross-linking increases from the center of the particle toward the surface. The degree of cross-linking may be configured to increase continuously or may be configured to increase discontinuously. The core particle (A) having such a configuration is formed by adding a monomer component and a crosslinkable monomer so that the ratio of the amount of the crosslinkable monomer to the amount of the monomer component increases with time when forming the particle. It can be manufactured by controlling the addition amount of the monomer.

In this aspect, the ratio of the amount of the crosslinkable monomer is preferably adjusted within the range of 0.01 to 20 parts by weight with respect to 100 parts by weight of the monomer component constituting the core particle (A). . The range is more preferably 0.05 to 15 parts by weight, still more preferably 0.08 to 12 parts by weight, and particularly preferably 0.1 to 10 parts by weight.

<Shell layer (B)>
The shell layer (B) is a polymer layer that covers the surface of the core particle (A) and is located on the surface side of the core-shell type graft copolymer particle. At least a portion of the shell layer (B) is preferably graft-bonded to the core particle (A), but the shell layer (B) also includes a non-graft-bonded polymer. The shell layer (B) improves the compatibility between the core-shell type graft copolymer particles and the thermoplastic resin, and the core-shell type graft copolymer particles can be dispersed in the state of primary particles in the resin composition. be possible.

The shell layer (B) includes at least a layer (b1) formed from a copolymer containing aromatic vinyl compound units and vinyl cyanide compound units in order to improve compatibility with the thermoplastic resin. The copolymer may further contain a (meth)acrylate unit.

Examples of the aromatic vinyl compound include, but are not limited to, styrene, α-methylstyrene, p-methylstyrene, p-isopropylstyrene, o-chlorostyrene, p-chlorostyrene and dichlorostyrene. Of these, styrene is preferred.

Although the vinyl cyanide compound is not particularly limited, examples thereof include acrylonitrile and methacrylonitrile. Of these, acrylonitrile is preferred.

The (meth)acrylic acid ester is not particularly limited, and examples thereof include methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and (meth)acrylic ester. (meth)acrylic acid alkyl esters such as octyl acid, dodecyl (meth)acrylate, stearyl (meth)acrylate, and behenyl (meth)acrylate; phenoxyethyl (meth)acrylate, benzyl (meth)acrylate, etc. aromatic ring-containing (meth)acrylates; hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate; glycidyls such as glycidyl (meth)acrylate and glycidylalkyl (meth)acrylate (Meth)acrylates; alkoxyalkyl (meth)acrylates, and the like.

From the viewpoint of compatibility with the thermoplastic resin, the proportion of the aromatic vinyl compound unit in the entire copolymer constituting the layer (b1) is preferably 30% by weight or more and 95% by weight or less, and 50% by weight or more. 90% by weight or less is more preferable, 60% by weight or more and 85% by weight or less is even more preferable, and 70% by weight or more and 82% by weight or less is particularly preferable. The proportion of the vinyl cyanide compound unit is preferably 5% by weight or more and 70% by weight or less, more preferably 10% by weight or more and 50% by weight or less, further preferably 15% by weight or more and 40% by weight or less, and 18% by weight or more. 30% by weight or less is particularly preferred. Furthermore, the proportion of the (meth)acrylic acid ester is preferably 0% by weight or more and 20% by weight or less, more preferably 10% by weight or less, further preferably 5% by weight or less, and particularly preferably 1% by weight or less. .

The shell layer (B) may be composed of the layer (b1) alone, or may further include an outer layer (b2) located outside the layer (b1) in addition to the layer (b1). The outer layer (b2) is preferably formed from a polymer containing aromatic vinyl compound units. By including such an outer layer (b2), the impact resistance of the thermoplastic resin can be further improved.

The aromatic vinyl compound that can be used in the outer layer (b2) is not particularly limited, and specific examples of the aromatic vinyl compound described above for the layer (b1) can be mentioned.
The polymer constituting the outer layer (b2) may be composed only of aromatic vinyl compound units, but may further contain vinyl cyanide compound units and/or (meth)acrylic acid ester units. .

The ratio of the aromatic vinyl compound units to the total polymer constituting the outer layer (b2) is preferably higher than the ratio of the aromatic vinyl compound units to the total copolymer constituting the layer (b1). By providing the outer layer (b2) having a relatively high proportion of aromatic vinyl compound units, it is possible to further improve the impact resistance of the thermoplastic resin. Specifically, the ratio of the aromatic vinyl compound units to the total polymer constituting the outer layer (b2) is preferably 50% by weight or more and 100% by weight or less, more preferably 70% by weight or more, and 75% by weight. % by weight or more is more preferable, and 80% by weight or more is particularly preferable.

The weight ratio of layer (b1):outer layer (b2) is not particularly limited, but may be, for example, about 30:70 to 99:1. 40:60 to 95:5 is preferable, and 50:50 to 90:10 is more preferable from the viewpoint of improving the compatibility with the thermoplastic resin and improving the impact resistance.

The shell layer (B) may be composed of only the layer (b1) and the outer layer (b2), or in addition to these two layers, a layer that is neither the layer (b1) nor the outer layer (b2) may be added. may contain.

The shell layer (B), layer (b1), and outer layer (b2) may be formed from a polymer having a crosslinked structure, but are preferably formed from a polymer having no crosslinked structure. That is, the shell layer (B), layer (b1) and outer layer (b2) are preferably formed from a polymer produced without using a crosslinkable monomer.

From the viewpoint of impact resistance, the proportion of the shell layer (B) in the entire core-shell type graft copolymer particles is preferably 20% by weight or more and 50% by weight or less. The lower limit is more preferably 22% by weight or more, still more preferably 25% by weight or more, and most preferably 27% by weight or more. The upper limit is more preferably 45% by weight or less, more preferably 40% by weight or less, even more preferably 35% by weight or less, and particularly preferably 32% by weight or less.

<Method for Producing Core-Shell Graft Copolymer Particles>
The production of the core-shell type graft copolymer particles is not particularly limited, but for example, emulsion polymerization, miniemulsion polymerization, microemulsion polymerization, or soap-free emulsion polymerization can be used. Among them, emulsion polymerization is preferred.

Emulsifiers that can be used in emulsion polymerization are not particularly limited, and anionic surfactants, nonionic surfactants, cationic surfactants, amphoteric surfactants and the like can be used. Dispersants such as polyvinyl alcohol, alkyl-substituted cellulose, polyvinylpyrrolidone and polyacrylic acid derivatives may also be used in combination.

The anionic surfactant is not particularly limited, but includes, for example, the following compounds: potassium laurate, potassium coconut fatty acid, potassium myristate, potassium oleate, potassium oleate diethanolamine salt, sodium oleate, palmitic acid. Fatty acid soaps such as potassium, potassium stearate, sodium stearate, mixed fatty acid soda soap, semi-hardened tallow fatty acid soda soap, castor oil potassium soap; sodium dodecyl sulfate, sodium higher alcohol sulfate, triethanolamine dodecyl sulfate, ammonium dodecyl sulfate, poly Alkyl sulfate ester salts such as sodium oxyethylene alkyl ether sulfate, triethanolamine polyoxyethylene alkyl ether sulfate, sodium polyoxyethylene alkylphenyl ether sulfate, sodium 2-ethylhexyl sulfate; sodium alkylbenzene sulfonate such as sodium dodecylbenzene sulfonate; sodium dialkylsulfosuccinate such as sodium di-2-ethylhexylsulfosuccinate; sodium alkylnaphthalenesulfonate; sodium alkyldiphenyletherdisulfonate; potassium alkylphosphate; phosphate ester salts such as sodium polyoxyethylene lauryl ether phosphate; Sodium salt of acid formalin condensate; polycarboxylic acid type polymer anion; sodium acyl (beef tallow) methyl taurate; sodium acyl (coconut) methyl taurate; sodium cocoyl isethionate; α-sulfo fatty acid ester sodium salt; sodium sulfonate; oleyl sarcosine; lauroyl sarcosine sodium; rosinate soap;

The nonionic surfactant is not particularly limited, but includes, for example, the following compounds: polyoxyethylene alkylallyl ethers such as polyoxyethylene nonylphenyl ether, polyoxyethylene oleyl ether, polyoxyethylene lauryl ether; Polyoxyethylene alkyl ethers, polyoxyethylene sorbitan esters such as polyoxyethylene sorbitan monolaurate and polyoxyethylene sorbitan monostearate, polyethylene glycol monolaurate, polyethylene glycol monostearate, polyethylene glycol monooleate polyoxyethylene fatty acid esters such as ate, oxyethylene/oxypropylene block copolymers, and the like.

The cationic surfactant is not particularly limited, but includes, for example, the following compounds: alkylamine salts such as coconutamine acetate, stearylamine acetate, octadecylamine acetate, tetradecylamine acetate; lauryltrimethylammonium chloride; quaternary ammonium salts such as stearyltrimethylammonium chloride, cetyltrimethylammonium chloride, distearyldimethylammonium chloride, alkylbenzyldimethylammonium chloride, hexadecyltrimethylammonium chloride, behenyltrimethylammonium chloride;

The amphoteric surfactant is not particularly limited, but includes, for example, the following compounds: laurylbetaine, stearylbetaine, alkylbetaines such as dimethyllaurylbetaine; sodium lauryldiaminoethylglycinate; amidobetaine; imidazoline; Ethylimidazolinium betaine, etc.

These emulsifiers may be used alone or in combination of two or more. As the emulsifier, sodium dialkylsulfosuccinate or a surfactant having an oxyethylene structure is preferred, and sodium polyoxyethylene lauryl ether phosphate is particularly preferred. By adjusting the amount of emulsifier used, the average particle size of the polymer particles can be controlled.

When the emulsion polymerization method is employed, known polymerization initiators such as 2,2′-azobisisobutyronitrile, hydrogen peroxide, potassium persulfate and ammonium persulfate can be used as thermal decomposition initiators. can.

In addition, organic peroxides such as t-butylperoxyisopropyl carbonate, paramenthane hydroperoxide, cumene hydroperoxide, dicumyl peroxide, t-butyl hydroperoxide, di-t-butyl peroxide and t-hexyl peroxide Oxides; peroxides such as inorganic peroxides such as hydrogen peroxide, potassium persulfate and ammonium persulfate; sodium formaldehyde sulfoxylate; glucose; transition metal salts such as iron (II) sulfate; a chelating agent; and at least one reducing agent selected from the group consisting of pyrophosphates such as sodium pyrophosphate.

When a redox initiator is used, polymerization can be carried out at a low temperature at which the peroxide is not substantially thermally decomposed, and the polymerization temperature can be set within a wide range, which is preferable. Among them, organic peroxides such as cumene hydroperoxide, dicumyl peroxide and t-butyl hydroperoxide are preferably used as redox initiators. The amount of the initiator used, and the amount of the reducing agent, transition metal salt, chelating agent, etc. used when a redox initiator is used may be within a known range. A known chain transfer agent can be used in a known amount when polymerizing the crosslinkable monomer. Surfactants can additionally be used and are within the known range.

As the solvent used for emulsion polymerization, any solvent can be used as long as it allows the emulsion polymerization to proceed stably.

The temperature during emulsion polymerization is not particularly limited as long as the emulsifier is uniformly dissolved in the solvent.

Specifically, the core-shell type graft copolymer particles according to the present disclosure can be produced by sequentially performing the following steps (I) to (III). However, step (III) is an optional step and may not be carried out.
Step (I): First, in the presence of an emulsifier and an initiator, a monomer component containing an alkyl (meth)acrylate, the reactive ultraviolet absorber, and a crosslinkable monomer are polymerized to absorb the reactive ultraviolet light. The agent forms core particles (A) which are particles of polyalkyl (meth)acrylate rubber copolymerized with the agent. At this time, it is preferable to form the rubber particles so that the degree of cross-linking on the surface of the rubber particles is higher than the degree of cross-linking on the inside of the rubber particles.

According to one aspect of the present embodiment, in step (I), a monomer component containing an alkyl (meth)acrylate and the reactive ultraviolet absorber and a crosslinkable monomer are subjected to multistage polymerization to obtain the inner layer, 1 or A core particle (A) composed of a plurality of intermediate layers and outer layers can be formed.

To give an example, first, a monomer component containing an alkyl (meth)acrylate and the reactive ultraviolet absorber, a crosslinkable monomer, an initiator, etc. are added and polymerized to form particles of the core inner layer. . Then, to the system containing the particles of the core inner layer, a monomer component containing alkyl (meth)acrylate and the reactive ultraviolet absorber, a crosslinkable monomer, and, if necessary, an initiator and the like are added to further polymerize. to form a core intermediate layer covering the core inner layer. Furthermore, a monomer component containing an alkyl (meth)acrylate, a crosslinkable monomer, and, if necessary, an initiator and the like are added to the system including the core inner layer and the core intermediate layer, and polymerization is further performed to obtain the core intermediate layer. to form a core outer layer that covers the At this time, the ratio of the amount of the crosslinkable monomer to the monomer component when forming the core outer layer is higher than the ratio of the amount of the crosslinkable monomer to the monomer component when forming the core inner layer or the core intermediate layer. is set high, it is possible to form rubber particles in which the degree of cross-linking on the surface is higher than the degree of cross-linking on the inside.

According to another aspect of the present embodiment, in step (I), polymerization is performed while adding a monomer component and a crosslinkable monomer to the reaction system, and at that time, the crosslinkable monomer for the monomer component The amount of the monomer component and the crosslinkable monomer added is controlled so that the ratio of the amounts increases with time. As a result, it is possible to form rubber particles in which the degree of cross-linking increases from the center to the surface of the rubber particles. The ratio of the crosslinkable monomer amount to the monomer component may be increased continuously or discontinuously. Moreover, it may increase linearly or may increase non-linearly. Incidentally, the monomer component and the crosslinkable monomer may be added separately, or may be mixed and added.

Step (II): To the system containing the core particles (A) obtained in Step (I), a monomer component containing an aromatic vinyl compound and a vinyl cyanide compound and, if necessary, an initiator and the like are added. , in the presence of the core particles (A), the monomer component is copolymerized to form a layer (b1) composed of a copolymer containing an aromatic vinyl compound unit and a vinyl cyanide compound unit. . Thereby, a core-shell type graft copolymer particle containing the core particle (A) and the layer (b1) which is the shell layer (B) can be obtained.

Step (III): To the system containing the core-shell type graft copolymer particles obtained in Step (II), a monomer component containing an aromatic vinyl compound and, if necessary, an initiator and the like are added to form the core-shell. By copolymerizing the monomer components in the presence of the type-grafted copolymer particles, the outer layer (b2) composed of a polymer containing aromatic vinyl compound units is formed. Thereby, a core-shell type graft copolymer particle including a core particle (A) and a layer (b1) and an outer layer (b2) as a shell layer (B) can be obtained.

A latex of the core-shell type graft copolymer particles is obtained by carrying out the steps (I) to (III). A powder of the polymer particles can be obtained by aggregating the polymer particles in the latex.
A method for aggregating the polymer fine particles is not particularly limited, and a known method can be applied. For example, (a) a latex and a flocculant (e.g., alkaline earth metal salts such as calcium chloride, magnesium chloride, and magnesium sulfate; alkali metal salts such as sodium chloride and sodium sulfate; hydrochloric acid, sulfuric acid, phosphoric acid, and acetic acid); (e.g., an acid such as an acid) or an aqueous solution containing the flocculant) to form a slurry (for example, by mixing), followed by heat treatment as necessary, followed by dehydration and drying; (c) freezing and then thawing the latex; (d) applying shear stress to the latex; (e) spray drying the latex; mentioned.

<Resin composition>
By blending the core-shell type graft copolymer particles according to the present disclosure with a thermoplastic resin to form a resin composition, the impact resistance and weather resistance of the thermoplastic resin can be enhanced.

The thermoplastic resin preferably contains a copolymer containing an aromatic vinyl compound unit and a vinyl cyanide compound unit.
The aromatic vinyl compound constituting the copolymer is not particularly limited, but examples include styrene, α-methylstyrene, p-methylstyrene, p-isopropylstyrene, o-chlorostyrene, p-chlorostyrene, dichlorostyrene, and the like. is mentioned. These may use only 1 type and may use 2 or more types together. Among these, styrene and α-methylstyrene are preferred, and styrene is particularly preferred.

Although the vinyl cyanide compound constituting the copolymer is not particularly limited, examples thereof include acrylonitrile and methacrylonitrile. These may use only 1 type and may use 2 types together. Acrylonitrile is preferred.

The copolymer may be a copolymer composed only of aromatic vinyl compound units and vinyl cyanide compound units. It may be a copolymer further containing.

The other copolymerizable vinyl compound is not particularly limited, but examples include methyl methacrylate, ethyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, methyl acrylate, ethyl acrylate, butyl acrylate, and acrylic acid. (Meth)acrylic acid alkyl esters having an alkyl group of 1 to 12 carbon atoms such as 2-ethylhexyl, maleimide compounds such as maleimide, N-phenylmaleimide, cyclohexylmaleimide, acrylic acid, methacrylic acid, isopropenylnaphthalene, acrylamide , methacrylamide, glycidyl acrylate, glycidyl methacrylate, and the like. These may use only 1 type and may use 2 or more types together.

The content of the aromatic vinyl compound in the copolymer is not particularly limited, but is preferably 60 to 85% by weight, more preferably 65 to 80% by weight. Although the content of the vinyl cyanide compound is not particularly limited, it is preferably 15 to 40% by weight, more preferably 20 to 35% by weight. The content of the other copolymerizable vinyl compound is also not particularly limited, but is preferably 0 to 25% by weight, more preferably 0 to 15% by weight.

Specific examples of the copolymer include styrene-acrylonitrile copolymer, α-methylstyrene-acrylonitrile copolymer, styrene-α-methylstyrene-acrylonitrile copolymer, styrene-maleimide-acrylonitrile copolymer, styrene- α-methylstyrene-maleimide-acrylonitrile copolymer, styrene-acrylonitrile-methyl methacrylate copolymer, α-methylstyrene-acrylonitrile-methyl methacrylate copolymer, styrene-α-methylstyrene-acrylonitrile-methyl methacrylate copolymer, Styrene-maleimide-acrylonitrile-methyl methacrylate copolymer, styrene-α-methylstyrene-maleimide-acrylonitrile-methyl methacrylate copolymer, and the like. These may use only 1 type and may use 2 or more types together.

The thermoplastic resin contained in the resin composition may be the copolymer alone, or may further contain a thermoplastic resin other than the copolymer. Although such thermoplastic resins are not particularly limited, examples thereof include acrylic resins such as polymethylmethacrylic acid, vinyl chloride resins, polycarbonate resins, amide resins, and polyester resins. These may use only 1 type and may use 2 or more types together. The content of the thermoplastic resin other than the copolymer may be about 0 to 50% by weight, may be 0 to 30% by weight, or may be 0 to 10% by weight with respect to the total thermoplastic resin. may be from 0 to 5% by weight, or from 0 to 1% by weight.

The content of the core-shell type graft copolymer particles in the resin composition is preferably 10 to 100 parts by weight with respect to 100 parts by weight of the thermoplastic resin from the viewpoint of improving impact resistance and weather resistance. , more preferably 15 to 80 parts by weight, more preferably 20 to 60 parts by weight, and particularly preferably 25 to 50 parts by weight.

The resin composition may optionally contain a flame retardant, an antibacterial agent, a release agent, a nucleating agent, a plasticizer, an antioxidant, a heat stabilizer, a light stabilizer, an ultraviolet absorber, a compatibilizer, a pigment, and a dye. , an antistatic agent, a lubricant, and the like may be added as appropriate. A blending amount of each additive can be appropriately determined by those skilled in the art. These may use only 1 type and may use 2 or more types together.

In particular, phenol-based, sulfur-based, phosphorus-based, and hindered amine-based antioxidants or stabilizers; benzophenone-based, benzotriazole-based UV absorbers; organopolysiloxanes, aliphatic hydrocarbons, esters of higher fatty acids and higher alcohols, Internal lubricants and external lubricants such as amides or bisamides of higher fatty acids and modified products thereof, oligoamides, and metal salts of higher fatty acids can be preferably added.

The resin composition can be produced, for example, by mixing the core-shell type graft copolymer particles and the thermoplastic resin in the form of latex, slurry, solution, powder, pellets, or a combination thereof. can. In the case of the latex containing the core-shell type graft copolymer particles and the thermoplastic resin, the polymer particles and the thermoplastic resin are contained by aggregating the polymer particles and the thermoplastic resin in the latex. powder can be obtained. As a method for aggregating the polymer particles and the thermoplastic resin, a known method can be applied, and specifically, the method described above can be used as a method for aggregating the polymer fine particles.

The resin composition is prepared by blending the core-shell type graft copolymer particles and the thermoplastic resin powder, pellets, etc. with optional additives as necessary, followed by Banbury mixer, roll mill, single-screw extruder, or twin-screw extruder. It can be kneaded by a known melt-kneader such as an extruder, and shaped into a target molded body by a known molding method such as injection molding, extrusion molding, blow molding, and the like.

The resin composition can be used in various applications such as electrical/electronic applications, construction applications, and vehicle applications. Specifically, personal computers, liquid crystal displays, projectors, PDAs, printers, copiers, fax machines, video cameras, digital cameras, mobile phones (smartphones), portable audio equipment, game machines, DVD recorders, microwave ovens, rice cookers, etc. Electrical and electronic applications; Architectural applications such as translucent plates for roads, lighting windows, carports, lighting lenses, lighting covers, sizing for building materials, doors; It can be used for vehicle applications such as display, illumination, driver's seat panel, and the like.

EXAMPLES The present invention will be described in more detail with reference to examples below, but the present invention is not limited to these examples. Hereinafter, "%" indicates "% by weight" unless otherwise specified.

(Method for measuring volume average particle size of polymer particles)
The volume average particle diameter of polymer particles was measured in the state of polymer particle latex. Nanotrac Wave manufactured by Nikkiso Co., Ltd. was used as a measuring device. The calculation mode was set to UPA compatible mode.

(Polymerization conversion rate)
A part of the obtained latex was sampled and accurately weighed, dried in a hot air dryer at 120° C. for 1 hour, and the weight after drying was accurately weighed as the solid content. Next, the ratio of the results of accurate weighing before and after drying was determined as the solid component ratio in the latex. Finally, using this solid content ratio, the polymerization conversion rate was calculated by the following equation.
Polymerization conversion rate = (total weight of charged raw materials × solid content ratio - total weight of raw materials other than monomer) / weight of charged monomer × 100 (%)

(Example 1)
(core inner layer)
180 parts by weight of deionized water and 0.00075 parts by weight of sodium dioctylsulfosuccinate (Pelex OT-P manufactured by Kao Corporation) were put into an 8 L polymerization machine, heated to 45° C., and nitrogen was flowed.

5 parts by weight of butyl acrylate (abbreviated as "BA"), 0.00625 parts by weight of allyl methacrylate (abbreviated as "ALMA") (0.125% based on monomer), and 0.015% of 69% t-butyl hydroperoxide A mixture of parts by weight was added to the polymerizer, and disodium ethylenediaminetetraacetate and ferrous sulfate were dissolved in deionized water at a mixing ratio of 5:3 to a concentration of 0.5% by weight. 0.0033 parts by weight and 0.04 parts by weight of 5% by weight sodium formaldehyde sulfoxylate were added and stirred for 30 minutes. The particle diameter of the obtained particles was 200 nm. Then, 19.77 parts by weight of butyl acrylate, the reactive ultraviolet absorber represented by the formula (1) (DAINSORB T-31 manufactured by Daiwa Kasei Co., Ltd., compound name: 2-(2'-hydroxy-5'-methacryloxyethyl Phenyl)-2H-benzotriazole, hereinafter referred to as "RUVA") 0.23 parts by weight, allyl methacrylate 0.025 parts by weight (0.125% relative to the monomer), and 69% t-butyl hydroperoxide An additional 0.006 parts by weight of the mixture was added over 60 minutes. This formed particles corresponding to the core inner layer.

(Core intermediate layer)
Then, 19.77 parts by weight of butyl acrylate, 0.23 parts by weight of RUVA, 0.05 parts by weight of allyl methacrylate (0.25% relative to the monomer), and 0.006 parts by weight of 69% t-butyl hydroperoxide. Additional parts by weight of the mixture were added over 60 minutes. This formed the first intermediate layer of the core particles.
Then 19.77 parts by weight of butyl acrylate, 0.23 parts by weight of RUVA, 0.1 parts by weight of allyl methacrylate (0.50% relative to monomer), and 0.006 parts by weight of 69% t-butyl hydroperoxide. Additional parts by weight of the mixture were added over 60 minutes. This formed the second intermediate layer of the core particles.

(core outer layer)
After 30 minutes, a mixture of 5 parts by weight butyl acrylate, 0.45 parts by weight allyl methacrylate (9% on monomer), and 0.01 parts by weight 69% t-butyl hydroperoxide was added over 15 minutes. Then, 0.012 parts by weight of 69% t-butyl hydroperoxide was added and stirred for 30 minutes. This formed a core outer layer to obtain a core particle (A). The volume average particle diameter of the core particles was 500 nm.

(shell layer)
Then 22.5 parts by weight of styrene (abbreviation "ST"), 7.5 parts by weight of acrylonitrile (abbreviation "AN"), 0.15 parts by weight of 69% t-butyl hydroperoxide, and 25% of polyoxyethylene lauryl A mixture of 1.46 parts by weight of saponified sodium hydroxide of ether phosphoric acid (Phosphanol RD-510Y manufactured by Toho Chemical Industry Co., Ltd.) was added over 120 minutes.
t-Butyl hydroperoxide and sodium formaldehyde sulfoxylate are added as appropriate to form the layer (b1) which is the shell layer (B), and the core-shell type graft having a conversion rate of 100% and a solid content concentration of 32.3% A copolymer latex was obtained.

(Example 2)
Core particles (A) were produced in the same manner as in Example 1.

(Layer (b1))
Then, 17.5 parts by weight of styrene, 7.5 parts by weight of acrylonitrile, 0.1 part by weight of 69% t-butyl hydroperoxide, and 25% polyoxyethylene lauryl ether phosphate (Phosphanol manufactured by Toho Chemical Industry Co., Ltd.) A mixture of 1.46 parts by weight of saponified sodium hydroxide of RD-510Y) was added over 100 minutes to form layer (b1).

(Outer layer (b2))
Furthermore, after 15 minutes, a mixture of 5 parts by weight of styrene and 0.05 parts by weight of 69% t-butyl hydroperoxide was added over 20 minutes to form an outer layer (b2), t-butyl hydroperoxide, and By appropriately adding sodium formaldehyde sulfoxylate, a core-shell type graft copolymer latex having a conversion rate of 100% and a solid content concentration of 32.1% was obtained. The core-shell type graft copolymer has a layer (b1) and an outer layer (b2) as a shell layer (B).

(Examples 3-9 and Comparative Examples 1-6)
In Examples 3, 5 to 9, and Comparative Examples 2 to 6, core-shell graft copolymer latexes were obtained in the same manner as in Example 2, except that the amount of each component added was changed according to Table 1. rice field.
In Example 4 and Comparative Example 1, the volume average particle diameter of the core particles (A) was adjusted to the value shown in Table 1 by adjusting the initial amount of sodium dioctylsulfosuccinate added. A core-shell type graft copolymer latex was obtained in the same manner as above.

<Granulation of core-shell type graft copolymer>
A calcium chloride aqueous solution was added to each core-shell type graft copolymer latex obtained above to prepare a slurry. After that, it was dehydrated with a centrifugal dehydrator, washed with deionized water, and dried at 50° C. for 2 days to obtain powder of each core-shell type graft copolymer.

(Method for measuring Izod impact strength)
35 parts by weight of the resulting core-shell type graft copolymer powder, 64.6 parts by weight of AS resin (PN-117, manufactured by Chimei), and a carbon black masterbatch (40% carbon black mixed with AS resin). 0.6 parts by weight was added and kneaded by an extruder (TEX44SS manufactured by Japan Steel Works, Ltd.) to obtain pellets. These pellets were injected with an injection molding machine (160MSP manufactured by Mitsubishi Heavy Industries, Ltd.) to obtain a 1/8 inch bar with a thickness of 3 mm. Notched Izod impact strength was measured at 23° C. in accordance with JIS K-7110. Table 1 shows the results.

(Method for measuring weather resistance (ΔE))
Using an accelerated weathering tester (X75 manufactured by Suga Test Instruments Co., Ltd.), the test piece was left for 1,500 hours in accordance with GB / T16422.2, and then the degree of discoloration was measured with a color difference meter. was applied to calculate the ΔE value.

Here, ΔE is the arithmetic mean value of the CIE L, a, b values before and after the weather resistance test, and the closer the value is to 0, the better the weather resistance.

From Table 1, Examples 1 to 9 have higher Izod impact strength values and better impact resistance than Comparative Examples 1 to 4, and ΔE compared to Comparative Examples 4 to 6. It can be seen that the value is small and the weather resistance is good.

In Comparative Example 1, the core particles (A) have a small volume average particle size of 350 nm. In Comparative Example 2, the proportion of the core particles (A) in the entire core-shell type graft copolymer is as small as 45% by weight. In Comparative Example 3, the proportion of the core particles (A) in the entire core-shell type graft copolymer is as large as 85% by weight. In Comparative Examples 4 and 5, the core particles (A) were not copolymerized with RUVA, and in Comparative Example 6, RUVA was not copolymerized with the core particles (A), but was copolymerized with the shell layer (B). be.

Claims (10)

A core-shell type graft copolymer particle comprising a core particle (A) and a shell layer (B) covering the core particle (A),
The core particle (A) contains a polyalkyl (meth)acrylate rubber,
At least part of the polyalkyl (meth)acrylate rubber is copolymerized with a reactive ultraviolet absorber represented by the following formula (1),
The core particle (A) has a volume average particle diameter of 400 to 800 nm,
The proportion of the core particles (A) in the core-shell type graft copolymer particles is 50 to 80% by weight,
The core-shell type graft copolymer particles, wherein the shell layer (B) includes a layer (b1) of a copolymer containing aromatic vinyl compound units and vinyl cyanide compound units.

In formula (1), X represents hydrogen or halogen, R ¹ represents hydrogen, a methyl group, or a t-alkyl group having 4 to 6 carbon atoms, and R ² represents a linear or branched represents an alkylene group having 2 to 10 carbon atoms, and R ³ represents hydrogen or a methyl group; 2. The core-shell type graft copolymer particle according to claim 1, wherein the core particle (A) is configured such that the degree of cross-linking on the surface of the particle is higher than the degree of cross-linking on the inside of the particle. The core particle (A) is composed of an inner layer, one or more intermediate layers, and an outer layer,
3. The core-shell type graft copolymer particle according to claim 1, wherein the outer layer has a higher degree of cross-linking than the inner layer and the intermediate layer. 4. The core-shell type graft copolymer particles according to claim 1, wherein the reactive ultraviolet absorber is copolymerized with the polyalkyl (meth)acrylate rubber of the intermediate layer. 5. The core-shell type graft copolymer particle according to claim 1, wherein said outer layer polyalkyl (meth)acrylate rubber is not copolymerized with said reactive ultraviolet absorber. The shell layer (B) further includes an outer layer (b2) located outside the layer (b1),
The core-shell type graft copolymer particle according to any one of claims 1 to 5, wherein the outer layer (b2) is formed from a polymer containing aromatic vinyl compound units. A method for producing the core-shell type graft copolymer particles according to any one of claims 1 to 6,
a step of polymerizing a monomer component containing an alkyl (meth)acrylate and a crosslinkable monomer to form core particles (A) composed of a polyalkyl (meth)acrylate rubber;
In the presence of the core particle (A), a monomer component containing an aromatic vinyl compound and a vinyl cyanide compound is copolymerized to form a shell layer (B), and the core-shell type graft copolymer particle is obtained. A manufacturing method comprising the step of obtaining. In the step of forming the core particles (A), the core particles (A) are composed of an inner layer, one or more intermediate layers, and an outer layer by multistage polymerization of a monomer component containing an alkyl (meth)acrylate and a crosslinkable monomer. 8. The production method according to claim 7, wherein the core particles (A) are formed. 100 parts by weight of a thermoplastic resin containing a copolymer containing aromatic vinyl compound units and vinyl cyanide compound units, and
A resin composition comprising 10 to 100 parts by weight of the core-shell type graft copolymer particles according to any one of claims 1 to 6. A molded article obtained by molding the resin composition according to claim 9 .