JP7404701B2 - Graft copolymers, thermoplastic resin compositions and molded products thereof - Google Patents

Description

The present invention provides core-shell particles and a graft copolymer that provide a thermoplastic resin composition with excellent molded appearance, impact resistance, and fluidity, and a thermoplastic resin composition containing this graft copolymer. Regarding the molded product.

Improving the impact resistance of resin materials is extremely useful industrially, as it not only expands the uses of resin materials but also allows molded products to be made thinner and larger. Various methods have been proposed to date to improve the impact resistance of resin materials. Among these, a method of increasing impact resistance while maintaining the properties of the hard resin material by combining a rubbery polymer and a hard resin material has already been industrialized. Such materials include acrylonitrile-butadiene-styrene (ABS) resin.

However, although ABS resin has excellent impact resistance and molded appearance, it has been difficult to use it without applying decorations such as painting or film because the weather resistance of polybutadiene, which is a rubber component, is low.

In order to solve such problems with ABS resins, acrylonitrile-styrene-acrylic acid ester (ASA) resins using acrylic rubber as the rubber component have been developed and are being commercialized.

For example, Patent Document 1 discloses a method in which an acrylonitrile-styrene (AS) resin is used as a hard resin material and an ASA resin is added thereto.
However, since the ASA resin has a large refractive index difference between the hard resin component acrylonitrile-styrene (AS) resin and the acrylic rubber, the molded appearance is poor when molded at a low injection speed. Furthermore, when molding is performed at a high injection speed, there is a problem in that the molded appearance further deteriorates.

Patent Document 2 and Patent Document 3 disclose a method in which a polybutadiene/acrylic rubber composite having a structure in which the outside of polybutadiene particles is covered with acrylic rubber is added to an AS resin.
With this method, by combining polybutadiene, the difference in refractive index between the rubber component and the AS resin becomes smaller, resulting in a better molded appearance. However, there is a problem that weather resistance decreases due to the combination of polybutadiene.

Patent Document 4 discloses a method of increasing the refractive index of acrylic rubber by copolymerizing butyl acrylate and styrene.
However, in the method described in Patent Document 4, the impact resistance is significantly reduced. Further, although the molded appearance is good when molded at a low injection speed, there is a problem in that the molded appearance is poor when molded at a high injection speed.

JP2017-71660A Japanese Patent Application Publication No. 2007-204763 Japanese Patent Application Publication No. 2009-242595 Japanese Patent Application Publication No. 2017-88774

The present invention provides core-shell type particles and a graft copolymer that provide a thermoplastic resin composition that has excellent molded appearance, impact resistance, and fluidity, and a thermoplastic resin composition containing this graft copolymer. Our goal is to provide such molded products.

As a result of repeated studies to solve the above problems, the present inventor polymerized a vinyl monomer mixture (m1) containing (meth)acrylic acid alkyl ester (a) as rubber particles of a graft copolymer. A copolymer obtained by polymerizing a core part made of a copolymer (A) obtained by It has been found that by using core-shell type particles (C) having a shell portion consisting of the coalescence (B), it is possible to obtain a thermoplastic resin composition that has excellent molded appearance, impact resistance, and fluidity. Ta.

That is, the gist of the present invention is as follows.

[1] A core part made of a copolymer (A) obtained by polymerizing a vinyl monomer mixture (m1) containing a (meth)acrylic acid alkyl ester (a), and an aromatic hydrocarbon group ( Core-shell type particles (C) having a shell portion made of a copolymer (B) obtained by polymerizing a vinyl monomer mixture (m2) containing a meth)acrylic acid ester (b).

[2] The content of copolymer (A) in 100% by mass of core-shell particles (C) is 35 to 97% by mass, and the content of copolymer (B) is 3 to 65% by mass. Copolymer (A) according to [1].

[3] Copolymer (A) contains (meth)acrylic acid alkyl ester (a) units and units derived from a crosslinking agent and/or units derived from a grafting agent [1] or [2] The core-shell type particle (C) described in .

[4] The proportion of units derived from the crosslinking agent and/or graft cross-linking agent in the copolymer (A) is the (meth)acrylic acid alkyl ester (a) unit and the unit derived from the cross-linking agent and/or graft cross-linking agent. The core-shell type particle (C) according to [3], which is 0.01 to 3% by mass out of 100% by mass in total with units derived from crossagents.

[5] The copolymer (B) contains a (meth)acrylic acid ester (b) unit having an aromatic hydrocarbon group, and a unit derived from a crosslinking agent and/or a unit derived from a graft crosslinking agent, [ The core-shell type particle (C) according to any one of [1] to [4].

[6] The proportion of units derived from the crosslinking agent and/or grafting agent in the copolymer (B) is the proportion of units derived from the (meth)acrylic acid ester (b) having an aromatic hydrocarbon group and the units derived from the crosslinking agent. The core-shell type particle (C) according to [5], which is 0.01 to 3% by mass out of 100% by mass in total with the units.

[7] The volume average particle diameter of the copolymer (A) is 50 to 800 nm, and the degree of swelling is 2 to 15 times, and the volume average particle diameter of the core-shell type particles (C) is 60 to 820 nm, and the degree of swelling is 2 to 15 times. The core-shell type particle (C) according to any one of [1] to [6], which has a particle size of 2 to 15 times.

[8] A graft copolymer (D) obtained by graft polymerizing a vinyl monomer mixture (m3) to the core-shell particles (C) according to any one of [1] to [7].

[9] The vinyl monomer mixture (m3) contains an aromatic vinyl monomer and a vinyl cyanide monomer, and the aromatic vinyl monomer contained in the vinyl monomer mixture (m3) The graft copolymer (D) according to [8], wherein the content of the vinyl cyanide monomer is 40 to 90% by mass, and the content of the vinyl cyanide monomer is 10 to 60% by mass.

[10] The proportion of the core-shell type particles (C) is 50 to 80% by mass with respect to the total of 100% by mass of the core-shell type particles (C) and the vinyl monomer mixture (m3), and the vinyl monomer mixture (m3) The graft copolymer (D) according to [8] or [9], wherein the proportion of the body mixture (m3) is 20 to 50% by mass and the grafting rate is 25 to 100%.

[11] A thermoplastic resin composition comprising the graft copolymer (D) according to any one of [8] to [10].

[12] The thermoplastic resin composition according to [11], comprising the graft copolymer (D) and the copolymer (E) which is a polymerization reaction product of the vinyl monomer mixture (m4).

[13] The vinyl monomer mixture (m3) contains an aromatic vinyl monomer and a vinyl cyanide monomer, and the vinyl monomer mixture (m4) contains a vinyl monomer mixture (m3) An aromatic vinyl monomer with the same structure as the aromatic vinyl monomer contained in , and a vinyl cyanide monomer with the same structure as the vinyl cyanide monomer contained in the vinyl monomer mixture (m3) The thermoplastic resin composition according to [12], which contains a monomer.

[14] 10 to 50% by mass of graft copolymer (D) and 50 to 90% by mass of copolymer (E) in a total of 100% by mass of graft copolymer (D) and copolymer (E). %, the thermoplastic resin composition according to [12] or [13].

[15] A molded article obtained by molding the thermoplastic resin composition according to any one of [11] to [14].

According to the present invention, a thermoplastic resin composition having excellent molded appearance, impact resistance, and fluidity, and a molded article thereof are provided.

Embodiments of the present invention will be described in detail below.
In the present invention, "(meth)acrylic acid" means one or both of "acrylic acid" and "methacrylic acid," and the same applies to "(meth)acrylate."
In addition, the term "unit" refers to a structural part derived from a compound (monomer, monomer) before polymerization, which is contained in a polymer, and includes, for example, "(meth)acrylic acid alkyl ester (a) unit ” means “a structural portion derived from (meth)acrylic acid alkyl ester (a) and contained in the copolymer (A) that is the core portion of the core-shell type particle (C).” The content ratio of each monomer unit in the polymer corresponds to the content ratio of the monomer in the monomer mixture used for producing the polymer.

[Core-shell particles (C)]
The core-shell type particles (C) of the present invention have a core portion made of a copolymer (A) obtained by polymerizing a vinyl monomer mixture (m1) containing a (meth)acrylic acid alkyl ester (a). and a shell portion made of a copolymer (B) obtained by polymerizing a vinyl monomer mixture (m2) containing a (meth)acrylic acid ester (b) having an aromatic hydrocarbon group. be.

<Mechanism>
A (meth)acrylic acid ester having an aromatic hydrocarbon group is contained in the vinyl monomer mixture (m1), and the copolymer (A) is a (meth)acrylic acid alkyl ester and a (meth)acrylic acid ester having an aromatic hydrocarbon group. When a copolymer of meth)acrylic acid ester is used, the refractive index of the copolymer (A) becomes large. That is, the refractive index of the core-shell type particles (C) increases, and the refractive index difference between the graft layer of the graft copolymer (D) and the copolymer (E), which will be described later, and the core-shell type particles (C) increases. Since it is smaller, the molded appearance is improved. However, problems such as an increase in the glass transition temperature of the copolymer (A) occur, resulting in a decrease in low-temperature impact resistance.

On the other hand, the vinyl monomer mixture (m1) forming the copolymer (A) is mainly composed of (meth)acrylic acid alkyl ester, and the vinyl monomer mixture (m2) forming the shell part is the main component. When the component is a (meth)acrylic acid ester having an aromatic hydrocarbon group, the refractive index of the shell part is high and the refractive index of the core part is low, and there is a refractive index inside the core-shell type particle (C). A slope is created. That is, the graft layer of the graft copolymer (D) and the copolymer (E) have the highest refractive index, the shell portion has the next highest refractive index, and the core portion has the lowest refractive index. Copolymerization between the graft layer of the polymer (D) and the copolymer (E) and the core-shell type particle (C), and the graft layer of the graft copolymer (D) and the copolymerization between the copolymer (E) and the core part A structure is formed in which the refractive index gradually changes between coalescence (A). Therefore, when the graft copolymer (D) using the core-shell type particles (C) of the present invention is blended with the copolymer (E), light scattering by the core-shell type particles (C) can be suppressed and the molded appearance can be improved. If the core part is mainly composed of (meth)acrylic acid ester units having an aromatic hydrocarbon group, and the shell part is mainly composed of (meth)acrylic acid alkyl ester units, the graft copolymer (D) Between the graft layer and the copolymer (E) and the core-shell particle (C), and between the graft layer of the graft copolymer (D) and the core part of the copolymer (E) and the copolymer (A). The structure does not have a gradual change in refractive index, and the molded appearance is poor.

In the core-shell type particles (C) of the present invention, since the copolymer (A) mainly composed of (meth)acrylic acid alkyl ester (a) units, which is the core part, has a low glass transition temperature, the core part A certain copolymer (A) contributes to low-temperature impact resistance, while, as described above, copolymer (B), which is a shell portion, contributes to improving the molded appearance.
Therefore, the copolymer (A) obtained by polymerizing the vinyl monomer mixture (m1) containing the (meth)acrylic acid alkyl ester (a) has an aromatic hydrocarbon group in the core part (meth). By using the copolymer (B) obtained by polymerizing the vinyl monomer mixture (m2) containing the acrylic acid ester (b) as the shell part, both molded appearance and impact resistance can be achieved.

If the rubber particles are not core-shell type but are made of a copolymer of an alkyl (meth)acrylic ester and an (meth)acrylic ester having an aromatic hydrocarbon group, the molded appearance will be improved, but the rubber Low temperature impact resistance is reduced due to the low glass transition temperature of the particles.

A copolymer (A) obtained by polymerizing a vinyl monomer mixture (m1) containing a (meth)acrylic acid alkyl ester (a) is used as a core part, and (meth)acrylic acid has an aromatic hydrocarbon group. Graft copolymer (D) using core-shell type particles (C) whose shell portion is a copolymer (B) obtained by polymerizing a vinyl monomer mixture (m2) containing an ester (b) In a thermoplastic resin composition containing this graft copolymer (D), two glass transition temperatures are observed in the low temperature region of 0°C to -150°C.
On the other hand, when the rubber particles are not core-shell type and are a copolymer of an alkyl (meth)acrylate ester and a (meth)acrylate ester having an aromatic hydrocarbon group, 0°C Only one glass transition temperature is observed in the low temperature region of ~-150°C.
Here, the glass transition temperature can be measured by DSC or dynamic viscoelasticity measurement (for example, temperature dispersion measurement at a frequency of 1 Hz).

<Copolymer (A)>
The copolymer (A) is obtained by polymerizing a vinyl monomer mixture (m1) containing a (meth)acrylic acid alkyl ester (a).

The (meth)acrylic acid alkyl ester (a) is preferably a (meth)acrylic acid alkyl ester in which the alkyl group has 1 to 12 carbon atoms. Among these, n-butyl acrylate, 2-ethylhexyl acrylate, and ethyl acrylate are particularly preferred because the resulting thermoplastic resin composition has excellent impact resistance. (Meth)acrylic acid alkyl esters can be used alone or in combination of two or more.

The copolymer (A) may have, in addition to the (meth)acrylic acid alkyl ester (a), one or both of a unit derived from a crosslinking agent and a unit derived from a graft crosslinking agent. Preferably, when the copolymer (A) contains units derived from a grafting agent and/or a crosslinking agent, the effect of further improving the molded appearance and impact resistance of the resulting thermoplastic resin composition is achieved. .

Examples of the graft cross-agent include allyl compounds, specifically allyl methacrylate, triallyl cyanurate, triallyl isocyanurate, and the like. These may be used alone or in combination of two or more.

Examples of the crosslinking agent include dimethacrylate compounds, specific examples of which include ethylene glycol dimethacrylate, propylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, and 1,4-butylene glycol dimethacrylate. These may be used alone or in combination of two or more.

When a crosslinking agent and/or a grafting agent is used, the proportion of units derived from the crosslinking agent and/or grafting agent in the copolymer (A) depends on the molded appearance and impact resistance of the resulting thermoplastic resin composition. Because of the excellent Preferably, 0.05 to 2% by mass is more preferable.

The copolymer (A) may contain (meth)acrylic acid alkyl ester (a) units, units derived from a crosslinking agent and/or grafting agent used as necessary, to the extent that the object of the present invention is not impaired. It may also contain other monomer units. Other monomer units that may be included in the copolymer (A) include vinyl units other than the (meth)acrylic acid alkyl ester (a) contained in the vinyl monomer mixture (m3) described below. One or more types of monomer units may be mentioned, but in order to effectively obtain the effects of the present invention, the content of these other vinyl monomer units should be 100% by mass of the copolymer (A). %, preferably 20% by mass or less, particularly 10% by mass or less, and for the above-mentioned reasons, it is preferred that the (meth)acrylic acid ester (b) unit having an aromatic hydrocarbon group is not included.

The method for producing the copolymer (A) is not particularly limited, but may include emulsion polymerization or miniemulsion polymerization of a mixture containing the (meth)acrylic acid alkyl ester (a) and a crosslinking agent and/or a grafting agent. is preferred, and miniemulsion polymerization is particularly preferred since the resulting thermoplastic resin composition has excellent physical properties.

The method for producing copolymer (A) by emulsion polymerization involves adding a radical initiator, (meth)acrylic acid alkyl ester (a), a crosslinking agent and/or a grafting agent to an aqueous solvent, and adding an emulsifier. Examples include a method of copolymerizing in the presence of.
The radical initiator, the (meth)acrylic acid alkyl ester (a), the crosslinking agent and/or the grafting agent may be added all at once, in portions, or continuously.

Although the miniemulsion polymerization for producing the copolymer (A) is not limited to this, for example, (meth)acrylic acid alkyl ester (a), a crosslinking agent and/or a grafting agent, and a hydrophobic A step of mixing a substance and an initiator, adding water and an emulsifier to the resulting mixture, and applying shear force to create a pre-emulsion (mini-emulsion), and heating this mixture to a polymerization initiation temperature. The method may include a step of polymerizing the polymer.

In the mini-emulsion process, for example, by carrying out a shearing process using ultrasonic irradiation, the monomer is torn off by the shearing force, and minute oil droplets of the monomer covered with the emulsifier are formed. Thereafter, by heating to the polymerization initiation temperature of the initiator, the monomer minute oil droplets are directly polymerized to obtain polymer fine particles. Any known method can be used to apply shearing force to form a mini-emulsion, and high-shear devices that can form a mini-emulsion include, but are not limited to, for example, high-pressure pumps and There are emulsification devices consisting of an interaction chamber, devices that form mini-emulsions using ultrasonic energy or high frequency waves, and the like. Examples of emulsifying devices consisting of a high-pressure pump and an interaction chamber include the "Pressure Homogenizer" manufactured by SPX Corporation APV and the "Microfluidizer" manufactured by Powrec Co., Ltd., which can generate mini-emulsions using ultrasonic energy or high frequency. Examples of the forming device include, but are not limited to, "Sonic Dismembrator" manufactured by Fisher Scient and "ULTRASONIC HOMOGENIZER" manufactured by Nippon Seiki Seisakusho Co., Ltd., for example.

In addition, from the viewpoint of workability, stability, manufacturability, etc., the amount of water solvent used during mini-emulsion formation is such that the solid content concentration of the reaction system after polymerization is about 5 to 50% by mass. The amount is preferably about 100 to 500 parts by mass per 100 parts by mass of the mixture other than the above.

When producing the copolymer (A) by miniemulsion polymerization, it is preferable to use a hydrophobic substance in a predetermined ratio. When a hydrophobic substance is added when forming a pre-emulsion, the production stability of mini-emulsion polymerization tends to be further improved, and a copolymer (A) suitable for the present invention can be produced.

Examples of hydrophobic substances include hydrocarbons having 10 or more carbon atoms, alcohols having 10 or more carbon atoms, hydrophobic polymers having a mass average molecular weight (Mw) of less than 10,000, and hydrophobic monomers such as alcohols having 10 to 30 carbon atoms. Vinyl ester, vinyl ether of alcohol having 12 to 30 carbon atoms, alkyl (meth)acrylate having 12 to 30 carbon atoms, vinyl ester of carboxylic acid having 10 to 30 carbon atoms (preferably 10 to 22 carbon atoms), p-alkylstyrene , hydrophobic chain transfer agents, hydrophobic peroxides, and the like. These may be used alone or in combination of two or more.

More specifically, the hydrophobic substances include hexadecane, octadecane, icosane, liquid paraffin, liquid isoparaffin, paraffin wax, polyethylene wax, olive oil, cetyl alcohol, stearyl acrylate, lauryl acrylate, stearyl acrylate, and lauryl methacrylate. , stearyl methacrylate, polystyrene having a number average molecular weight (Mn) of 500 to 10,000, poly(meth)acrylic ester, and the like.

The hydrophobic substance is preferably 0.1 to 10 parts by mass, more preferably 1 to 3 parts by mass, based on a total of 100 parts by mass of the (meth)acrylic acid alkyl ester (a) and the crosslinking agent and/or grafting agent. From the viewpoint of controlling the particle size of the copolymer (A), it is preferable to use 100% of the copolymer (A).

Examples of emulsifiers used in producing the copolymer (A) include carboxylic acid emulsifiers exemplified by oleic acid, palmitic acid, stearic acid, alkali metal salts of rosin acid, alkali metal salts of alkenylsuccinic acid, etc. Known emulsifiers such as anionic emulsifiers selected from alkyl sulfates, sodium alkylbenzenesulfonates, sodium alkylsulfosuccinates, sodium polyoxyethylene nonyl phenyl ether sulfates, etc. may be used alone or in combination of two or more. can.

The amount of the emulsifier added is preferably 0.01 to 3.0 parts by mass, more preferably 0.01 to 3.0 parts by mass, based on a total of 100 parts by mass of the (meth)acrylic acid alkyl ester (a), the crosslinking agent and/or the grafting agent. The amount is preferably 0.05 to 1.5 parts by mass from the viewpoint of controlling the particle size of the copolymer (A).

The initiator used in the production of copolymer (A) is a radical polymerization initiator for radical polymerization, and there are no particular restrictions on its type, but examples include azo polymerization initiators, photopolymerization initiators, and inorganic peroxides. Examples thereof include organic peroxides, redox initiators that are a combination of organic peroxides, transition metals, and reducing agents. Among these, preferred are azo polymerization initiators, inorganic peroxides, organic peroxides, and redox initiators that can initiate polymerization by heating. These may be used alone or in combination of two or more.

Examples of the azo polymerization initiator include 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'- Azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), 1,1'-azobis(cyclohexane-1-carbonitrile), 1-[(1-cyano-1-methylethyl) azo]formamide, 4,4'-azobis(4-cyanovaleric acid), dimethyl 2,2'-azobis(2-methylpropionate), dimethyl 1,1'-azobis(1-cykhexanecarboxylate) ), 2,2'-azobis[2-methyl-N-(2-hydroxyethyl)propionamide], 2,2'-azobis(N-butyl-2-methylpropionamide), 2,2'-azobis( N-cyclohexyl-2-methylpropionamide), 2,2'-azobis[2-(2-imidazolin-2-yl)propane], 2,2'-azobis(2,4,4-trimethylpentane), etc. Can be mentioned.

Examples of the inorganic peroxide include potassium persulfate, sodium persulfate, ammonium persulfate, and hydrogen peroxide.

Examples of organic peroxides include peroxy ester compounds, specific examples of which include α,α'-bis(neodecanoylperoxy)diisopropylbenzene, cumylperoxyneodecanoate, 1,1,3, 3-tetramethylbutylperoxyneodecanoate, 1-cyclohexyl-1-methylethylperoxyneodecanoate, t-hexylperoxyneodecanoate, t-butylperoxyneodecanoate, t-hexylperoxypivalate, t-Butylperoxypivalate, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, 2,5-dimethyl-2,5-bis(2-ethylhexanoylperoxy)hexane, 1- Cyclohexyl-1-methylethylperoxy-2-ethylhexanoate, t-hexylperoxy 2-hexylhexanoate, t-butylperoxy 2-hexylhexanoate, t-butylperoxyisobutyrate, t-hexylperoxyisopropyl Monocarbonate, t-butylperoxymaleic acid, t-butylperoxy 3,5,5-trimethylhexanoate, t-butylperoxylaurate, 2,5-dimethyl-2,5-bis(m-toluoylperoxy) ) hexane, t-butylperoxyisopropyl monocarbonate, t-butylperoxy2-ethylhexyl monocarbonate, t-hexylperoxybenzoate, 2,5-dimethyl-2,5-bis(benzoylperoxy)hexane, t-butylperoxyacetate, t-Butylperoxy-m-toluoylbenzoate, t-butylperoxybenzoate, bis(t-butylperoxy)isophthalate, 1,1-bis(t-hexylperoxy)3,3,5-trimethylcyclohexane, 1,1 -bis(t-hexylperoxy)cyclohexane, 1,1-bis(t-butylperoxy)3,3,5-trimethylcyclohexane, 1,1-bis(t-butylperoxy)cyclohexane, 1,1-bis(t-butylperoxy)cyclohexane -butylperoxy)cyclododecane, 2,2-bis(t-butylperoxy)butane, n-butyl 4,4-bis(t-butylperoxy)valerate, 2,2-bis(4,4-di-t- butylperoxycyclohexyl)propane, α,α'-bis(t-butylperoxide)diisopropylbenzene, dicumylperoxide, 2,5-dimethyl-2,5-bis(t-butylperoxy)hexane, t-butylcumylperoxide , di-t-butyl peroxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, dilauroyl peroxide, diisononanoyl peroxide, t-butyl hydroperoxide, benzoyl peroxide, lauroyl peroxide, dimethylbis(t-butylperoxy)-3- Hexyne, bis(t-butylperoxyisopropyl)benzene, bis(t-butylperoxy)trimethylcyclohexane, butyl-bis(t-butylperoxy)valerate, t-butyl 2-ethylhexane peroxyate, dibenzoylperoxide, paramenthane hydro Examples include peroxide and t-butyl peroxybenzoate.

The redox initiator is preferably a combination of an organic peroxide, ferrous sulfate, a chelating agent, and a reducing agent. For example, a combination of cumene hydroperoxide, ferrous sulfate, sodium pyrophosphate, and dextrose, or a combination of t-butyl hydroperoxide, sodium formaldehyde sulfoxylate (Rongalit), ferrous sulfate, and disodium ethylenediaminetetraacetate. Examples include things such as

Among these, organic peroxides are particularly preferred as the initiator.

The amount of the initiator added is usually 5 parts by mass or less, preferably 3 parts by mass or less, for example, 5 parts by mass or less, preferably 3 parts by mass or less, per 100 parts by mass of the (meth)acrylic acid alkyl ester (a), crosslinking agent and/or grafting agent. It is 0.001 to 3 parts by mass.

The step of preparing the above pre-emulsion is usually carried out at room temperature (about 10 to 50°C), and the mini-emulsion polymerization step is carried out at 40 to 100°C for about 30 to 600 minutes.

The average particle diameter of the copolymer (A) dispersed in the aqueous dispersion is preferably 50 to 800 nm, more preferably 100 to 600 nm, even more preferably 250 to 450 nm, since the resulting molded product has excellent physical properties. .
Methods for controlling the average particle diameter of the copolymer (A) include, but are not particularly limited to, methods for adjusting the type or amount of emulsifier used.
Note that the average particle diameter of the copolymer (A) and the average particle diameter of the core-shell particles (C) described below refer to the volume average particle size measured by the method described in the Examples section below. It is the diameter.

Further, the degree of swelling of the copolymer (A) is preferably 2 to 15 times, more preferably 4 to 12 times, since the resulting thermoplastic resin composition has excellent impact resistance and molded appearance.
The degree of swelling of the copolymer (A) is measured by the method described in the Examples section below.

<Copolymer (B)>
The copolymer (B) is a copolymer obtained by polymerizing a vinyl monomer mixture (m2) containing a (meth)acrylic acid ester (b) having an aromatic hydrocarbon group. Copolymer (B) is an outer layer that encapsulates a core made of copolymer (A) obtained by polymerizing a vinyl monomer mixture (m1) containing (meth)acrylic acid alkyl ester (a). It constitutes a shell portion as a shell. Therefore, for example, by polymerizing the vinyl monomer mixture (m2) in the presence of the copolymer (A), the core part is the copolymer (A) and the shell part is the copolymer (B). Core-shell type particles (C) can be obtained.

The (meth)acrylic ester (b) having an aromatic hydrocarbon group contained in the vinyl monomer mixture (m2) may be any (meth)acrylic ester having an aromatic hydrocarbon group, For example, (meth)acrylic acid aryl esters, (meth)acrylic acid aryloxy esters, and aryl groups such as phenyl groups, aryloxy groups such as phenoxy groups, or arylalkyl groups such as benzyl groups as substituents on the alkyl ester moieties ( Examples include, but are not limited to, meth)acrylic acid alkyl esters. As the (meth)acrylic ester (b) having an aromatic hydrocarbon group, 2-phenoxyethyl acrylate is particularly preferred since the resulting thermoplastic resin composition has excellent impact resistance. The (meth)acrylic ester (b) having an aromatic hydrocarbon group can be used alone or in combination of two or more.

The copolymer (B) is a copolymer having one or both of a unit derived from a crosslinking agent and a unit derived from a graft crosslinking agent, in addition to the (meth)acrylic ester (b) having an aromatic hydrocarbon group. A polymer is preferable, and when the copolymer (B) contains units derived from a grafting agent and/or a crosslinking agent, the molded appearance and impact resistance of the resulting thermoplastic resin composition can be further improved. The effect of

As the graft cross-linking agent and cross-linking agent, those exemplified as the graft cross-linking agent and cross-linking agent used in the copolymer (A) can be used.

When a crosslinking agent and/or a grafting agent is used, the proportion of units derived from the crosslinking agent and/or grafting agent in the copolymer (B) depends on the molded appearance and impact resistance of the resulting thermoplastic resin composition. Since the (meth)acrylic acid ester (b) unit having an aromatic hydrocarbon group and the units derived from the crosslinking agent and/or the units derived from the grafting agent are combined in 100% by mass, 0. 0.01 to 3% by weight is preferable, and 0.05 to 2% by weight is more preferable.

The copolymer (B) may contain (meth)acrylic acid ester (b) units having an aromatic hydrocarbon group, a crosslinking agent and/or a grafting agent used as necessary, to the extent that the object of the present invention is not impaired. It may contain other monomer units other than the units derived from the cross-agent. Other monomer units that may be included in the copolymer (B) include (meth)acrylic acid esters (meth) having an aromatic hydrocarbon group contained in the vinyl monomer mixture (m3) described below. One or more types of vinyl monomer units other than b) may be used, but in order to effectively obtain the effects of the present invention, the content of these other vinyl monomer units should be set to a copolymer. It is preferably 20% by mass or less, particularly 10% by mass or less, based on 100% by mass of the combined (B), and for the reasons mentioned above, it is preferred that the (meth)acrylic acid alkyl ester (a) unit is not included.

<Core-shell type particles (C)>
The method for producing the core-shell particles (C) is not particularly limited, but when the copolymer (A) is produced by emulsion polymerization or miniemulsion polymerization, emulsion polymerization using a vinyl monomer mixture (m2) is performed. Preferably, it is manufactured by

Examples of the emulsion polymerization method include a method of radical polymerization by adding the vinyl monomer mixture (m2) all at once, continuously, or intermittently in the presence of an emulsion of the copolymer (A). It will be done. In addition, during polymerization of copolymer (B), a chain transfer agent may be used to adjust the molecular weight or grafting rate of copolymer (B), or a chain transfer agent may be used to adjust the viscosity and pH of the latex. A known inorganic electrolyte or the like may be used. Moreover, in emulsion polymerization, various emulsifiers and radical initiators can be used as necessary.

There are no particular restrictions on the type or amount of the emulsifier and radical initiator. Examples of the emulsifier and radical initiator include the emulsifier and radical initiator exemplified above in the description of the copolymer (A).

Since the resulting thermoplastic resin composition has excellent impact resistance and molded appearance, the proportion of the copolymer (B) in 100% by mass of the core-shell particles (C) is preferably 3 to 65% by mass, and 5% by mass. ~50% by mass is more preferred, and 10~30% by mass is even more preferred.
In addition, since the resulting thermoplastic resin composition has excellent impact resistance and molded appearance, the copolymer (A) in 100% by mass of the core-shell particles (C) is preferably 35 to 97% by mass, and 50% by mass. It is more preferably 95% by mass, and even more preferably 70-90% by mass.

The average particle diameter of the core-shell particles (C) dispersed in the aqueous dispersion is preferably 60 to 820 nm, more preferably 110 to 620 nm, and 260 to 470 nm, since the resulting molded product has excellent physical properties. More preferred.
Methods for controlling the average particle diameter of the core-shell type particles (C) are not particularly limited, but mainly include a method of adjusting the type or amount of emulsifier used during production of the copolymer (A).

The swelling degree of the core-shell type particles (C) is preferably 2 to 15 times, more preferably 4 to 12 times, since the resulting thermoplastic resin composition has excellent impact resistance and molded appearance.
The degree of swelling of the core-shell particles (C) is measured by the method described in the Examples section below.

[Graft copolymer (D)]
The graft copolymer (D) is obtained by graft polymerizing the vinyl monomer mixture (m3) in the presence of the core-shell particles (C).

The vinyl monomer mixture (m3) is composed of an aromatic vinyl monomer and a vinyl cyanide monomer because the resulting thermoplastic resin composition containing the graft copolymer (D) has excellent physical properties. It is preferable to include a polymer.

Examples of aromatic vinyl monomers contained in the vinyl monomer mixture (m3) include styrene, α-methylstyrene, o-, m- or p-methylstyrene, vinylxylene, pt-butyl Examples include styrene and ethylstyrene, and these can be used alone or in combination of two or more. There is no particular restriction on the structure of the aromatic vinyl monomer, but it is important that the structure of the aromatic vinyl monomer is the same as that of the aromatic vinyl monomer contained in the vinyl monomer mixture (m4) described below. It is also preferable in terms of impact resistance and molded appearance of the molded product.

The content of the aromatic vinyl monomer contained in the vinyl monomer mixture (m3) is 40 to 90% by mass in the thermoplastic resin prepared by blending the resulting graft copolymer (D). It is preferable in terms of impact resistance and molded appearance of the composition and its molded products, and more preferably 60 to 80% by mass.

Examples of the vinyl cyanide monomer contained in the vinyl monomer mixture (m3) include acrylonitrile and methacrylonitrile, and one or more of these can be used. There is no particular restriction on the structure of the vinyl cyanide monomer, but it is important that the resulting thermoplastic resin has the same structure as the vinyl cyanide monomer contained in the vinyl monomer mixture (m4) described below. It is preferable in terms of impact resistance and molded appearance of the composition and molded products thereof.

The content of the vinyl cyanide monomer contained in the vinyl monomer mixture (m3) is 10 to 60% by mass, and the thermoplastic resin is prepared by blending the resulting graft copolymer (D). It is preferable in terms of impact resistance and molded appearance of the composition and molded products thereof, and more preferably 20 to 40% by mass.

The vinyl monomer mixture (m3) may contain the above-mentioned aromatic vinyl monomers and vinyl cyanide monomers, and other vinyl monomers copolymerizable with these.
The content of other copolymerizable vinyl monomers in the vinyl monomer mixture (m3) is preferably 20% by mass or less, particularly 10% by mass or less.
Examples of other vinyl monomers include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, i-propyl methacrylate, n-butyl methacrylate, i-butyl methacrylate, t-butyl methacrylate, Methacrylic acid esters such as amyl methacrylate, isoamyl methacrylate, octyl methacrylate, 2-ethylhexyl methacrylate, decyl methacrylate, lauryl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, phenyl methacrylate, N-methylmaleimide, N-cycloalkyl such as N-ethylmaleimide, N-n-propylmaleimide, N-i-propylmaleimide, N-n-butylmaleimide, N-butylmaleimide, N-tert-butylmaleimide, N-cyclohexylmaleimide, etc. N-arylmaleimide such as maleimide, N-phenylmaleimide, N-alkyl substituted phenylmaleimide, N-chlorophenylmaleimide, maleimide-based compounds such as N-aralkylmaleimide, methyl acrylate, ethyl acrylate, propyl acrylate, acrylic acid Examples include acrylic esters such as butyl. These may be used alone or in combination of two or more.

In the graft copolymer (D), a vinyl monomer mixture (m3) is graft-polymerized onto core-shell particles (C).
The resulting thermoplastic resin composition blended with the graft copolymer (D) has excellent impact resistance and molded appearance, and in particular, the dependence of the molded appearance on injection speed can be reduced. The core-shell particles (C) and the vinyl monomer mixture (m3) used in the production contain 50 to 80% by mass of the core-shell particles (C) in 100% by mass of the graft copolymer (D), It is preferable that the vinyl monomer mixture (m3) is 20 to 50% by mass.

In addition, the graft copolymer (D) has a graft ratio of 25 to 100% because the resulting thermoplastic resin composition blended with the graft copolymer (D) has excellent impact resistance and molded appearance. It is preferable that there be. The grafting rate of the graft copolymer (D) is measured by the method described in the Examples section below.

The graft copolymer (D) is produced by a known method such as a bulk polymerization method, a solution polymerization method, a bulk suspension polymerization method, a suspension polymerization method, an emulsion polymerization method, or a miniemulsion polymerization method. Emulsion polymerization is preferred because the thermoplastic resin composition containing the copolymer (D) has good impact resistance.

As a method of emulsion graft polymerization, in the presence of an emulsion of core-shell type particles (C), a vinyl monomer mixture (m3) is added all at once, continuously, or intermittently, and radical polymerization is carried out. There are several methods. In addition, during graft polymerization, a chain transfer agent may be used to adjust the molecular weight of the graft copolymer (D) and the grafting rate, and a known inorganic electrolyte may be used to adjust the viscosity and pH of the latex. etc. may also be used. Moreover, in emulsion graft polymerization, various emulsifiers and radical initiators can be used as necessary.
There are no particular restrictions on the type or amount of the emulsifier and radical initiator. Examples of the emulsifier and radical initiator include the emulsifier and radical initiator exemplified above in the description of the copolymer (A).

The method for recovering the graft copolymer (D) from the aqueous dispersion of the graft copolymer (D) includes (i) aqueous dispersion of the graft copolymer (D) in hot water in which a coagulant is dissolved; (ii) semi-directly by spraying an aqueous dispersion of graft copolymer (D) into a heated atmosphere; Examples include a method for recovering the graft copolymer (D) (spray drying method).

Examples of the coagulant include inorganic acids such as sulfuric acid, hydrochloric acid, phosphoric acid, and nitric acid, and metal salts such as calcium chloride, calcium acetate, and aluminum sulfate. The coagulant is selected in accordance with the emulsifier used in polymerization. That is, when only carboxylic acid soap such as fatty acid soap or rosin acid soap is used, any coagulant may be used. When an emulsifier that exhibits stable emulsifying power even in an acidic region, such as sodium dodecylbenzenesulfonate, is included, it is necessary to use a metal salt.

The method for obtaining a dry graft copolymer (D) from a slurry graft copolymer (D) is as follows: (i) After eluting the emulsifier residue remaining in the slurry into water by washing, the slurry is Examples include a method of dehydrating with a centrifugal dehydrator or press dehydrator and further drying with a flash dryer, and (ii) a method of simultaneously performing dehydration and drying with a press dehydrator, extruder, etc. After drying, the graft copolymer (D) is obtained in the form of powder or particles. Alternatively, the graft copolymer (D) discharged from the compression dehydrator or extruder can be directly sent to an extruder or molding machine for producing a thermoplastic resin composition.

[Copolymer (E)]
The copolymer (E) is obtained by polymerizing the vinyl monomer mixture (m4).

The vinyl monomer mixture (m4) has the same composition as the vinyl monomer mixture (m3) described above because the thermoplastic resin composition obtained by blending the copolymer (E) has excellent physical properties. It is preferable that it is, and it is preferable that an aromatic vinyl monomer and a cyanide vinyl monomer are included.

Examples of the aromatic vinyl monomer contained in the vinyl monomer mixture (m4) include styrene, α-methylstyrene, o-, m- or p-methylstyrene, vinylxylene, pt-butyl Examples include styrene and ethylstyrene, and these can be used alone or in combination of two or more. There is no particular restriction on the structure of the aromatic vinyl monomer, but the obtained thermoplastic resin must have the same structure as the aromatic vinyl monomer contained in the vinyl monomer mixture (m3) described above. It is preferable in terms of impact resistance and molded appearance of the composition and molded products thereof.

The content of the aromatic vinyl monomer contained in the vinyl monomer mixture (m4) should be 40 to 90% by mass to improve the impact resistance of the resulting thermoplastic resin composition and its molded products. It is preferable from the viewpoint of appearance, and more preferably 60 to 80% by mass.

Examples of the vinyl cyanide monomer contained in the vinyl monomer mixture (m4) include acrylonitrile and methacrylonitrile, and one or more of these can be used. There is no particular restriction on the structure of the vinyl cyanide monomer, but the obtained thermoplastic resin must have the same structure as the vinyl cyanide monomer contained in the vinyl monomer mixture (m3) described above. It is preferable in terms of impact resistance and molded appearance of the composition and molded products thereof.

The content of the vinyl cyanide monomer contained in the vinyl monomer mixture (m4) should be 10 to 60% by mass to improve the impact resistance of the resulting thermoplastic resin composition and its molded products. It is preferable from the viewpoint of appearance, and more preferably 20 to 40% by mass.

The vinyl monomer mixture (m4) may contain the above-mentioned aromatic vinyl monomers and vinyl cyanide monomers, and other vinyl monomers copolymerizable with these.
The content of other copolymerizable vinyl monomers in the vinyl monomer mixture (m4) is preferably 20% by mass or less, particularly 10% by mass or less.
Examples of other vinyl monomers include those exemplified as other vinyl monomers that may be included in the vinyl monomer mixture (m3), and these other vinyl monomers are , one type can be used alone or two or more types can be used in combination.

There is no particular restriction on the weight average molecular weight of the copolymer (E), but it is preferably in the range of 10,000 to 300,000, particularly preferably in the range of 50,000 to 200,000. If the mass average molecular weight of the copolymer (E) is within the above range, the resulting thermoplastic resin composition will have excellent fluidity and impact resistance.
The weight average molecular weight of the copolymer (E) is measured by the method described in the Examples section below.

The method for producing the copolymer (E) is not particularly limited, and includes known methods such as emulsion polymerization, suspension polymerization, bulk polymerization, and solution polymerization. From the viewpoint of heat resistance of the resulting thermoplastic resin composition, suspension polymerization and bulk polymerization are preferred.

There are no particular restrictions on the polymerization initiator used in producing the copolymer (E), and examples thereof include organic peroxides.

During the production of copolymer (E), a chain transfer agent can be used to adjust the molecular weight of copolymer (E). The chain transfer agent is not particularly limited, but examples include mercaptans, α-methylstyrene dimer, and terpenes.

[Thermoplastic resin composition]
The thermoplastic resin composition of the present invention contains the above-mentioned graft copolymer (D) of the present invention, and preferably contains the graft copolymer (D) of the present invention and the above-mentioned copolymer (E). including.

The content of the graft copolymer (D) of the present invention in the thermoplastic resin composition of the present invention is 10% by mass when the total of the graft copolymer (D) and copolymer (E) is 100% by mass. The content of the copolymer (E) is preferably 50 to 90% by mass. When the content of the graft copolymer (D) and copolymer (E) is within the above range, the thermoplastic resin composition and the molded product thereof will have excellent impact resistance and molded appearance.

The thermoplastic resin composition of the present invention may contain other thermoplastic resins as necessary. Other thermoplastic resins are not particularly limited, and include, for example, polycarbonate resin, polybutylene terephthalate (PBT resin), polyethylene terephthalate (PET resin), polyvinyl chloride, polystyrene, polyacetal resin, modified polyphenylene ether (modified PPE resin), Examples include ethylene-vinyl acetate copolymer, polyarylate, liquid crystal polyester resin, polyethylene resin, polypropylene resin, fluororesin, and polyamide resin (nylon). These may be used alone or in combination of two or more.

The thermoplastic resin composition of the present invention may contain other commonly used additives during the production (mixing) and molding of the thermoplastic resin composition, within the range that does not impair the physical properties of the thermoplastic resin composition and its molded products. For example, lubricants, pigments, dyes, fillers (carbon black, silica, titanium oxide, etc.), heat resistant agents, oxidative deterioration inhibitors, weathering agents, mold release agents, plasticizers, antistatic agents, etc. can be blended. .

The thermoplastic resin composition of the present invention can be manufactured by a known method using a known apparatus. For example, a common method is a melt mixing method, and examples of equipment used in this method include an extruder, a Banbury mixer, a roller, a kneader, and the like. Mixing may be done either batchwise or continuously. Furthermore, there is no particular restriction on the mixing order of each component, as long as all the components are mixed uniformly.

[Molding]
The molded article of the present invention is obtained by molding the thermoplastic resin composition of the present invention. Examples of the molding method include injection molding, injection compression molding, extrusion, blow molding, vacuum molding, pressure molding, calendar molding, and inflation molding. Among these, the injection molding method and the injection compression molding method are preferable because they are excellent in mass production and can obtain molded products with high dimensional accuracy.

[Application]
Although there are no particular limitations on the uses of the thermoplastic resin composition and molded articles thereof of the present invention, the thermoplastic resin composition of the present invention and molded articles thereof have excellent impact resistance, molded appearance, and fluidity. Therefore, it is useful in a wide range of fields such as OA and home appliances, vehicles and ships, housing-related fields such as furniture and building materials, sanitary goods, stationery, toys, and sporting goods.

EXAMPLES The present invention will be described in more detail below with reference to Examples and Comparative Examples; however, the present invention is not limited to the following Examples unless it exceeds the gist thereof.
In the following, "part" means "part by mass" and "%" means "% by mass."

Various measurement and evaluation methods in the following Examples and Comparative Examples are as follows.

<Volume average particle diameter of copolymer (A) and core-shell particles (C)>
The volume of the copolymer (A) or core-shell type particles (C) dispersed in the aqueous dispersion was measured using Microtrac (“Nanotrac 150” manufactured by Nikkiso Co., Ltd.) and ion-exchanged water as the measurement solvent. The average particle size was measured.

<Swelling degree of copolymer (A) and core-shell particles (C)>
By drying the aqueous dispersion of copolymer (A) or core-shell particles (C) at 80°C for 24 hours, and then vacuum drying at 80°C for 24 hours, a film-like copolymer (A) or A dried core-shell type particle (C) was prepared. Let the weight of the obtained dry product be W1. After immersing 1 g of this dried product in 80 mL of acetone, the acetone was refluxed at 65 to 70° C. for 3 hours. Next, the obtained suspended acetone solution was centrifuged at 14,000 rpm for 30 minutes using a centrifuge (“CR21E” manufactured by Hitachi Koki Co., Ltd.) to separate precipitated components (acetone-insoluble components). Let W2 be the weight of the acetone-insoluble component. Thereafter, the acetone-insoluble components were vacuum dried at room temperature for 24 hours. The weight of the acetone-insoluble component after vacuum drying is defined as W3. The degree of swelling of the copolymer (A) and core-shell particles (C) is calculated using the following formula (1).
Swelling degree (%) = (W2/W3) x 100...(1)

<Graft rate of graft copolymer (D)>
1 g of graft copolymer (D) was added to 80 mL of acetone, heated under reflux at 65 to 70°C for 3 hours, and the resulting suspended acetone solution was placed in a centrifuge (“CR21E” manufactured by Hitachi Koki Co., Ltd.). The mixture was centrifuged at 14,000 rpm for 30 minutes to separate a precipitate component (acetone-insoluble component) and an acetone solution (acetone-soluble component). Then, the precipitated component (acetone-insoluble component) was dried, its mass (Y (g)) was measured, and the grafting rate was calculated using the following formula (2). In addition, Y in formula (2) is the mass (g) of the acetone-insoluble component of the graft copolymer (D), X is the total mass (g) of the graft copolymer (D) used when determining Y, The rubber fraction is the solid content concentration in the aqueous dispersion of core-shell particles (C) used for producing the graft copolymer (D).
Grafting ratio (mass%) = {(Y-X×rubber fraction)/X×rubber fraction}
×100...(2)

<Mass average molecular weight of copolymer (E)>
The mass average molecular weight of the copolymer (E) was measured by dissolving it in tetrahydrofuran (THF) using gel permeation chromatography (GPC) and was calculated in terms of standard polystyrene (PS).

[Example I-1: Production of core-shell particles (C-1)]
<Production of copolymer (A-1)>
First, a copolymer (A-1) was produced using the following formulation.

[Composition]
n-Butyl acrylate (BA) 48 parts Allyl methacrylate 0.19 parts Liquid paraffin (LP) 0.5 parts Dipotassium alkenylsuccinate (ASK) 0.29 parts Dilauroyl peroxide 0.29 parts Ion-exchanged water 140 parts

N-butyl acrylate, liquid paraffin, allyl methacrylate, dilauroyl peroxide, ion exchange water, and dipotassium alkenylsuccinate were charged into a reactor equipped with a reagent injection container, a cooling tube, a jacket heater, and a stirring device, and the mixture was heated at room temperature. A pre-emulsion was obtained by performing ultrasonic treatment at an amplitude of 35 μm for 20 minutes using ULTRASONIC HOMOGENIZER US-600 manufactured by Nippon Seiki Seisakusho Co., Ltd. The volume average particle diameter of the obtained latex was 270 nm.
The pre-emulsion was heated to 60°C to initiate radical polymerization. Due to polymerization, the liquid temperature rose to 78°C. The temperature was maintained at 75° C. for 30 minutes to complete polymerization, and a copolymer (A-1) dispersed in an aqueous dispersion was obtained.

<Production of core-shell particles (C-1)>
After producing the copolymer (A-1), while maintaining the internal temperature of the reactor at 75°C, add 0.0001 part of ferrous sulfate, 0.0003 part of ethylenediaminetetraacetic acid disodium salt, and 0.2 part of Rongalite. , and 5 parts of ion-exchanged water were added, and then 0.01 part of dipotassium alkenylsuccinate was added. Thereafter, a mixed solution consisting of 2 parts of 2-phenoxyethyl acrylate, 0.01 part of allyl methacrylate, and 0.004 part of t-butyl hydroperoxide was added dropwise at a rate of 0.26 parts/min to form a copolymer ( B-1) was polymerized to obtain an aqueous dispersion of core-shell particles (C-1).

[Examples I-2 to 8, Comparative Examples I-4, 5, 7: Core-shell particles (C-2) to (C-8), (C-12), (C-13), (C -15) Manufacturing]
The type and amount of monomers such as alkyl n-butyl (meth)acrylate and allyl methacrylate, dipotassium alkenylsuccinate, and dilauroyl peroxide, and the copolymer (A-1) when producing the copolymer (A-1). The types and amounts of monomers such as 2-phenoxyethyl acrylate, dipotassium alkenylsuccinate, allyl methacrylate, and t-butyl hydroperoxide when copolymerizing (B) are shown in Table 1 (Tables 1A and 1B). Core-shell particles (C-2) to (C-8), (C -12), (C-13), and (C-15) were obtained.

[Comparative Examples I-1 to I-3, 6: Production of rubber particles (C-9) to (C-11), (C-14)]
Table 1B shows the types and amounts of monomers such as alkyl n-butyl (meth)acrylate and allyl methacrylate, dipotassium alkenylsuccinate, and dilauroyl peroxide when producing copolymer (A-1). In the same manner as in the production of copolymer (A-1), non-core-shell type rubber particles consisting only of copolymers (A-9) to (A-11) and (A-14) were produced. Aqueous dispersions of (C-9) to (C-11) and (C-14) were obtained.

Volume average particle diameter and degree of swelling of copolymers (A-1) to (A-15) dispersed in the aqueous dispersions obtained in Examples I-1 to I-8 and Comparative Examples I-1 to 7 The volume average particle diameter and degree of swelling of the core-shell type particles or rubber particles (C-1) to (C-15) dispersed in the aqueous dispersion are shown in Table 1 (Tables 1A and 1B).

[Example II-1: Production of graft copolymer (D-1)]
After producing the core-shell particles (C-1), while maintaining the internal temperature of the reactor at 75°C, sulfuric acid was added to 50 parts (as solid content) of the core-shell particles (C-1). An aqueous solution consisting of 0.001 part of iron, 0.003 part of ethylenediaminetetraacetic acid disodium salt, 0.3 part of Rongalite, and 5 parts of ion-exchanged water was added, and then 0.1 part of dipotassium alkenylsuccinate was added. . Thereafter, a mixed solution consisting of 14 parts of acrylonitrile, 36 parts of styrene, and 0.17 parts of t-butyl hydroperoxide was added dropwise over 1 hour and 40 minutes to effect graft polymerization.

After the dropwise addition was completed, the internal temperature was maintained at 75°C for 10 minutes, and then cooled. When the internal temperature reached 60°C, an aqueous solution of 0.2 parts of dipotassium alkenylsuccinate dissolved in 5 parts of ion-exchanged water was added. did. Next, the aqueous dispersion of the reaction product was coagulated with an aqueous sulfuric acid solution, washed with water, and then dried to obtain a graft copolymer (D-1).

[Examples II-2 to 8, Comparative Examples II-1 to 7: Production of graft copolymers (D-2) to (D-15)]
Graft copolymer (D-2) was prepared in the same manner as graft copolymer (D-1) except that the type of core-shell particles or rubber particles (C) used was changed as shown in Table 2. ~(D-15) was obtained.

Table 2 shows the graft ratios of the graft copolymers (D-1) to (D-15) obtained in Examples II-1 to II-8 and Comparative Examples II-1 to II-7.

[Production of copolymer (E-1)]
In a pressure-resistant reaction vessel, 150 parts of ion-exchanged water, a mixture of 34 parts of acrylonitrile and 66 parts of styrene as a vinyl monomer mixture (m4), and 0.2 parts of 2,2'-azobis(isobutyronitrile), n -0.45 parts of octyl mercaptan, 0.47 parts of calcium hydroxyapatite, and 0.003 parts of potassium alkenylsuccinate were charged, the internal temperature was raised to 75°C, and a reaction was carried out for 3 hours. Thereafter, the temperature was raised to 90°C and maintained for 60 minutes to complete the reaction. The contents were repeatedly washed and dehydrated using a centrifugal dehydrator and dried to obtain a copolymer (E-1) with a mass average molecular weight of 95,000.

[Examples III-1 to 8, Comparative Examples III-1 to 7: Production and evaluation of thermoplastic resin composition]
Each component was mixed with the composition (parts by mass) shown in Table 3, 0.8 part of carbon black was further mixed therein, and 240 The mixture was melt-kneaded at ℃ to obtain a thermoplastic resin composition in the form of pellets. The melt volume rate of the obtained thermoplastic resin composition was evaluated by the following method. In addition, molded products obtained by injection molding the obtained thermoplastic resin composition were evaluated for molded appearance and impact resistance by the following methods.
The evaluation results are shown in Table 3.

[Each evaluation method]
<Measurement of melt volume rate (MVR)>
In accordance with ISO 1133:1997, the MVR of the thermoplastic resin composition at 220° C. was measured under a load of 98 N (10 kg). Note that MVR is a measure of fluidity of a thermoplastic resin composition, and a higher value means better fluidity.

<Injection molding 1>
Pellets of the thermoplastic resin composition obtained by melt-kneading are vertically molded using an injection molding machine (manufactured by Toshiba Machine Co., Ltd., "IS55FP-1.5A") under conditions of a cylinder temperature of 200 to 270°C and a mold temperature of 60°C. A molded article of 80 mm, width 10 mm, and thickness 4 mm was molded and used as a molded article for Charpy impact test (molded article (Ma1)).

<Injection molding 2>
The pellets of the thermoplastic resin composition obtained by melt-kneading were molded using an injection molding machine (manufactured by Toshiba Machine Co., Ltd., "IS55FP-1.5A") at a cylinder temperature of 200 to 270°C, a mold temperature of 60°C, and an injection rate of 7 g/ A molded product having a length of 100 mm, a width of 100 mm, and a thickness of 3 mm was molded under the conditions of 10 seconds, and was used as a molded product for appearance evaluation (molded product (Ma2)).

<Injection molding 3>
The pellets of the thermoplastic resin composition obtained by melt-kneading were molded using an injection molding machine (manufactured by Toshiba Machine Co., Ltd., "IS55FP-1.5A") at a cylinder temperature of 200 to 270°C, a mold temperature of 60°C, and an injection rate of 128 g/ A molded product having a length of 100 mm, a width of 100 mm, and a thickness of 3 mm was molded under the conditions of 10 seconds, and was used as a molded product for appearance evaluation (molded product (Ma3)).

<Appearance evaluation (1)>
The lightness L ^* of the molded product (Ma2) was measured using a spectrophotometer ("CM-3500d" manufactured by Konica Minolta Optics, Inc.) using the SCE method. Let L ^* thus measured be "L ^* (ma)". The lower the L ^* , the blacker the color and the better the appearance.

<Appearance evaluation (2)>
The lightness L ^* of the molded product (Ma3) was measured using a spectrophotometer ("CM-3500d" manufactured by Konica Minolta Optics, Inc.) using the SCE method. Let L ^* thus measured be "L ^* (mb)". The lower the L ^* , the blacker the color and the better the appearance.
When molding is performed under conditions of high injection speed, the rubber components in the resin are oriented, causing whitening and bronzing, resulting in an increase in L ^* . Therefore, the molded appearance under conditions of high injection speed is important.

<Appearance evaluation (3) (injection speed dependence evaluation of appearance)>
ΔL ^* was calculated from the formula ΔL ^* =(L ^* (mb)−L ^* (ma)) ² . The smaller ΔL ^* is, the smaller the dependence of the appearance on the injection speed is. Generally, in molded products such as vehicle parts, the injection speed differs depending on the location of the part. Therefore, with resins that are highly dependent on injection speed, poor appearance occurs such as color unevenness on the surface of the part during molding.

<Impact resistance evaluation: Charpy impact test>
Regarding molded products (Ma1), the Charpy impact strength (impact direction: edgewise). The higher the Charpy impact strength, the better the impact resistance.

As shown in Examples III-1 to III-8 in Table 3, according to each Example, thermoplastic resin compositions and molded articles with excellent impact resistance, fluidity, and appearance were obtained.

On the other hand, in Comparative Example III-1, the rubber particles were not of the core-shell type and had a (meth)acrylic acid alkyl ester unit as the main component, so the molded appearance was poor.
In Comparative Examples III-2 and III-3, the particles are not core-shell type and contain (meth)acrylic acid ester units having an aromatic hydrocarbon group, so the molded appearance is good, but the low temperature resistance is poor. Poor impact resistance.
Comparative Examples III-4 and Comparative Examples III-5 had poor impact resistance and molded appearance because the shell portion was not a (meth)acrylic acid ester unit having an aromatic hydrocarbon group.
Comparative Example III-6 had poor impact resistance and molded appearance because the particles were not of the core-shell type but were a copolymer of alkyl (meth)acrylate and styrene.
Comparative Example III-7 had poor molded appearance because the shell portion was composed of (meth)acrylic acid alkyl ester units.

Claims (9)

A core part made of a copolymer (A) obtained by polymerizing a vinyl monomer mixture (m1) containing a (meth)acrylic acid alkyl ester (a), and (meth)acrylic having an aromatic hydrocarbon group. A core-shell type particle (C) having a shell portion made of a copolymer (B) obtained by polymerizing a vinyl monomer mixture (m2) containing an acid ester (b),
(meth)acrylic acid alkyl ester (a) is n-butyl acrylate,
The content of vinyl monomer units other than the (meth)acrylic acid alkyl ester (a) units contained in the copolymer (A) is 20% by mass or less based on 100% by mass of the copolymer (A),
The copolymer (A) contains (meth)acrylic acid alkyl ester (a) units, units derived from a crosslinking agent and/or units derived from a grafting agent,
The proportion of units derived from the crosslinking agent and/or graft cross-agent in the copolymer (A) is the same as that of the (meth)acrylic acid alkyl ester (a) unit and the unit derived from the cross-linking agent and/or graft cross-agent. It is 0.01 to 3% by mass out of the total 100% by mass with the derived unit,
The copolymer (B) contains a (meth)acrylic acid ester (b) unit having an aromatic hydrocarbon group, a unit derived from a crosslinking agent and/or a unit derived from a grafting crosslinking agent,
The proportion of units derived from the crosslinking agent and/or grafting agent in the copolymer (B) is the (meth)acrylic acid ester (b) unit having an aromatic hydrocarbon group, the unit derived from the crosslinking agent, and A vinyl monomer mixture (m3) is graft-polymerized to core-shell particles (C) in an amount of 0.01 to 3% by mass out of a total of 100% by mass with units derived from a graft cross- agent. The graft copolymer (D) is
The vinyl monomer mixture (m3) contains an aromatic vinyl monomer and a vinyl cyanide monomer, and the content of the aromatic vinyl monomer contained in the vinyl monomer mixture (m3) is 40 to 90% by mass, and the content of vinyl cyanide monomer is 10 to 60% by mass . Claim 1, wherein the content of the copolymer (A) in 100% by mass of the core-shell particles (C) is 35 to 97% by mass, and the content of the copolymer (B) is 3 to 65% by mass. The graft copolymer (D) described in . The copolymer (A) has a volume average particle size of 50 to 800 nm and a swelling degree of 2 to 15 times, and the core-shell particles (C) have a volume average particle size of 60 to 820 nm and a swelling degree of 2. The graft copolymer (D) according to claim 1 or 2, which is ~15 times. The ratio of the core-shell type particles (C) to the total 100 mass% of the core-shell type particles (C) and the vinyl monomer mixture (m3) is 50 to 80% by mass, and the vinyl monomer mixture (m3) The graft copolymer (D) according to any one of claims 1 to 3 , wherein the proportion of m3) is 20 to 50% by mass and the graft ratio is 25 to 100%. A thermoplastic resin composition comprising the graft copolymer (D) according to any one of claims 1 to 4 . The thermoplastic resin composition according to claim 5 , comprising a graft copolymer (D) and a copolymer (E) which is a polymerization reaction product of a vinyl monomer mixture (m4). The vinyl monomer mixture (m3) contains an aromatic vinyl monomer and a vinyl cyanide monomer, and the vinyl monomer mixture (m4) is contained in the vinyl monomer mixture (m3). An aromatic vinyl monomer with the same structure as the aromatic vinyl monomer and a vinyl cyanide monomer with the same structure as the vinyl cyanide monomer contained in the vinyl monomer mixture (m3) The thermoplastic resin composition according to claim 6 , comprising: Containing 10 to 50% by mass of the graft copolymer (D) and 50 to 90% by mass of the copolymer (E) in a total of 100% by mass of the graft copolymer (D) and the copolymer (E), The thermoplastic resin composition according to claim 6 or 7 . A molded article obtained by molding the thermoplastic resin composition according to any one of claims 5 to 8 .