JP2019099698A - Graft copolymer, thermoplastic resin composition and molded article - Google Patents

Abstract

To provide a graft copolymer excellent in molding appearance and impact resistance, small in injection speed dependency of molding appearance, and excellent in flowability, a thermoplastic resin composition containing the graft copolymer, and a molded article thereof.SOLUTION: There is provided a thermoplastic resin composition containing a copolymer (A) of (meth)acrylic acid alkyl ester (Aa) and (meth)acrylic acid ester having an aromatic hydrocarbon group (Ab), and a graft copolymer (B) by graft polymerizing a vinyl monomer mixture (m1). There are provided a thermoplastic resin composition containing the graft copolymer (B) and a copolymer (C) obtained by polymerizing a vinyl monomer mixture (m2) and a molded article thereof.SELECTED DRAWING: None

Description

  The present invention provides a thermoplastic resin composition which is excellent in molding appearance and impact resistance, has a small injection speed dependency of molding appearance, and is also excellent in fluidity, and a thermoplastic containing the graft copolymer. The present invention relates to a resin composition and a molded article thereof.

  The improvement of the impact resistance of the resin material is extremely useful industrially, for example, it makes it possible not only to expand the application of the resin material but also to cope with thinning and enlargement of the molded product. Various methods have been proposed to improve the impact resistance of resin materials. Among them, a method of enhancing the impact resistance while maintaining the properties of the hard resin material by combining the rubber polymer and the hard resin material has already been industrialized. Such materials include acrylonitrile-butadiene-styrene (ABS) resins.

  However, although the ABS resin is excellent in impact resistance and molding appearance, it is difficult to use it without applying painting or decoration of a film, etc., because the weather resistance of polybutadieneone which is a rubber component is low.

  In order to solve the problem of such an ABS resin, acrylonitrile-styrene-acrylic ester (ASA) resin using acrylic rubber as a rubber component is developed and industrialized.

For example, Patent Document 1 discloses a method of using an acrylonitrile-styrene (AS) resin as a hard resin material and adding an ASA resin thereto.
However, since the ASA resin has a large difference in refractive index between an acrylonitrile-styrene (AS) resin which is a hard resin component and an acrylic rubber, the molding appearance at the time of molding at a low injection speed is bad. Further, there is a problem that the molding appearance is further deteriorated at the time of molding at a high injection speed.

Patent Document 2 and Patent Document 3 disclose a method of adding a polybutadiene / acrylic rubber composite having a structure in which the outside of polybutadiene particles is covered with acrylic rubber to an AS resin.
If it is this method, the refractive index difference of a rubber component and AS resin will become small by compounding polybutadiene, and a molding appearance will become favorable. However, there is a problem that the weather resistance is lowered because the polybutadiene is compounded.

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, impact resistance is significantly reduced. In addition, although the molding appearance at the time of molding at low injection speed is good, the molding appearance at the time of molding at high injection speed is deteriorated, that is, there is a problem that the injection speed dependency of the molding appearance is large. From the viewpoint of productivity, the molding appearance at a high injection speed is important, but it is also extremely important in practice that the molding appearance has a small injection speed dependency. That is, for example, in a molded part such as a vehicle part, since the injection speed varies depending on the part location, in the resin having a large injection speed dependency, appearance defects occur depending on the part location during molding, resulting in a loss of product value. It becomes.

JP, 2017-71660, A JP, 2007-204763, A JP, 2009-242595, A JP, 2017-88774, A

  The present invention provides a thermoplastic resin composition which is excellent in molding appearance and impact resistance, has a small injection speed dependency of molding appearance, and is also excellent in fluidity, and a thermoplastic containing the graft copolymer. It is an object of the present invention to provide a resin composition and a molded article thereof.

As a result of repeated investigations to solve the above problems, the present inventor found that a copolymer of (meth) acrylic acid alkyl ester (Aa) and (meth) acrylic acid ester (Ab) having an aromatic hydrocarbon group By using a graft copolymer (B) obtained by graft polymerization of a vinyl monomer mixture (m1) in the presence of (A), the molding appearance and impact resistance are excellent, and the injection speed of the molding appearance is obtained It has been found that it is possible to obtain a thermoplastic resin composition which has a small dependency and is also excellent in fluidity.
That is, the present invention provides the following.

[1] Vinyl-based monomer mixture (m1) to copolymer (A) of (meth) acrylic acid alkyl ester (Aa) and (meth) acrylic acid ester (Ab) having an aromatic hydrocarbon group A graft copolymer (B) obtained by graft polymerization of

[2] (Meta total of 100 mass% of (meth) acrylic acid alkyl ester (Aa) unit in copolymer (A) and (meth) acrylic acid ester (Ab) unit having aromatic hydrocarbon group ) The content of the acrylic acid alkyl ester (Aa) unit is 30 to 95% by mass, and the content of the (meth) acrylic acid ester (Ab) unit having an aromatic hydrocarbon group is 5 to 70% by mass, The graft copolymer (B) as described in 1].

[3] The copolymer (A) comprises a (meth) acrylic acid alkyl ester (Aa) unit, a (meth) acrylic acid ester (Ab) unit having an aromatic hydrocarbon group, a unit derived from a crosslinking agent, and The graft copolymer (B) according to [1] or [2], which contains a unit derived from a graft crossing agent.

[4] The proportion of units derived from the crosslinking agent and / or grafting agent in the copolymer (A) comprises (meth) acrylic acid alkyl ester (Aa) units and an aromatic hydrocarbon group (meth) The graft according to [3], which is 0.1 to 3% by mass in a total of 100% by mass of the acrylic ester (Ab) unit and the unit derived from the crosslinking agent and / or the unit derived from the graft crossing agent Copolymer (B).

[5] A copolymer (A) is a (meth) acrylic acid alkyl ester (Aa), an aromatic hydrocarbon group-containing (meth) acrylic acid ester (Ab), and a crosslinking agent and / or a grafting agent The graft copolymer (B) according to [3] or [4], which is a miniemulsion polymer of a mixture of a hydrophobic substance and an initiator.

[6] The graft copolymer (B) according to any one of [1] to [5], wherein the volume average particle diameter of the copolymer (A) is 50 to 800 nm and the degree of swelling is 2 to 15 times. .

[7] An aromatic vinyl-based monomer, wherein the vinyl-based monomer mixture (m1) contains an aromatic vinyl-based monomer and a vinyl cyanide-based monomer, and is contained in the vinyl-based monomer mixture (m1) The graft copolymer (B) according to any one of [1] to [6], which has a content of 40 to 90% by mass and a content of a vinyl cyanide monomer of 10 to 60% by mass. .

[8] The proportion of the copolymer (A) is 50 to 80% by mass with respect to the total 100% by mass of the copolymer (A) and the vinyl monomer mixture (m1), and the vinyl monomer mixture (m1) The graft copolymer (B) according to any one of [1] to [7], wherein the ratio of 20) to 50% by mass, and the graft ratio is 25 to 100%.

[9] A thermoplastic resin composition comprising the graft copolymer (B) according to any one of [1] to [8].

[10] The thermoplastic resin composition according to [9], which comprises a graft copolymer (B) and a copolymer (C) which is a polymerization reaction product of a vinyl monomer mixture (m2).

[11] The vinyl monomer mixture (m1) contains an aromatic vinyl monomer and a vinyl cyanide monomer, and the vinyl monomer mixture (m2) is a vinyl monomer mixture (m1) And vinyl cyanide having the same structure as that of the vinyl vinyl monomer contained in the vinyl monomer mixture (m1). The thermoplastic resin composition as described in [10] which contains a monomer.

[12] 10 to 40 mass% of the graft copolymer (B) and 60 to 90 mass of the copolymer (C) in 100 mass% of the total of the graft copolymer (B) and the copolymer (C) The thermoplastic resin composition as described in [10] or [11] containing%.

[13] A molded article obtained by molding the thermoplastic resin composition according to any one of [9] to [12].

  According to the present invention, a thermoplastic resin composition which is excellent in molded appearance and impact resistance, has a small injection speed dependency of the molded appearance, and is also excellent in 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”.
Further, “unit” means a structural part derived from a compound (monomer, ie, monomer) before polymerization, which is contained in a polymer, and, for example, “(meth) acrylic acid alkyl ester (Aa) unit "" Means a structural moiety derived from (meth) acrylic acid alkyl ester (Aa) and contained in the copolymer (A). The content ratio of each monomer unit of the polymer corresponds to the content ratio of the monomer in the monomer mixture used for the production of the polymer.

[Graft copolymer (B)]
The graft copolymer (B) of the present invention is a copolymer (A) of a (meth) acrylic acid alkyl ester (Aa) and an aromatic hydrocarbon group-containing (meth) acrylic acid ester (Ab) And the graft copolymer of the vinyl-based monomer mixture (m1) in the presence of “the copolymer (A) of the present invention”.

<Copolymer (A)>
The copolymer (A) of the present invention is a copolymer of (meth) acrylic acid alkyl ester (Aa) and (meth) acrylic acid ester (Ab) having an aromatic hydrocarbon group.

  The (meth) acrylic acid alkyl ester (Aa) is preferably a (meth) acrylic acid alkyl ester having 1 to 12 carbon atoms in the alkyl group. Among them, n-butyl acrylate, 2-ethylhexyl acrylate, and ethyl acrylate are particularly preferable because the impact resistance of the thermoplastic resin composition obtained by blending the obtained graft copolymer (B) is excellent. The (meth) acrylic acid alkyl ester (Aa) can be used alone or in combination of two or more.

  The (meth) acrylic acid ester (Ab) having an aromatic hydrocarbon group may be a (meth) acrylic acid ester having an aromatic hydrocarbon group, for example, (meth) acrylic acid aryl ester or (meth) acrylic acid Examples of the acid aryloxy ester and alkyl ester moiety include (meth) acrylic acid alkyl ester having aryl group such as phenyl group and aryloxy group such as phenoxy group as a substituent, but it is not limited thereto. As the (meth) acrylic acid ester (Ab) having an aromatic hydrocarbon group, since the impact resistance of the thermoplastic resin composition obtained by blending the obtained graft copolymer (B) is excellent, benzyl acrylate is preferable. And 2-phenoxyethyl acrylate are particularly preferred. The (meth) acrylic acid ester (Ab) having an aromatic hydrocarbon group can be used alone or in combination of two or more.

  The content of the (meth) acrylic acid alkyl ester (Aa) unit in the copolymer (A) and the content of the (meth) acrylic acid ester (Ab) unit having an aromatic hydrocarbon group are the obtained graft copolymer (Meth) acrylic acid alkyl ester (Aa) unit, because the molding appearance and impact resistance of the thermoplastic resin composition formed by compounding the united body (B) are excellent, and in particular the injection speed dependency of the molding appearance can be reduced. 30 to 95 mass% of (meth) acrylic acid alkyl ester (Aa) units having an aromatic hydrocarbon group in 100 mass% of (meth) acrylic acid ester (Ab) units having an aromatic hydrocarbon group It is preferable that a (meth) acrylic acid ester (Ab) unit is 5-70 mass%, and a (meth) acrylic acid alkyl ester (Aa) unit is 50-90 mass%, and aroma It is further preferred having a hydrocarbon group (meth) acrylic acid ester (Ab) unit is 10 to 50 mass%.

  The content of the (meth) acrylate (Ab) unit in the copolymer (A) and the (meth) acrylate (Ab) unit having an aromatic hydrocarbon group is the same as that of the copolymer (A) or the graft copolymer After the thermoplastic resin composition containing the polymer (B) or the graft copolymer (B) and the copolymer (C) described later and the molded article thereof are heated to 600 ° C. and decomposed into monomer units Can be calculated by component analysis using a GC-MS apparatus, but as described above, the (meth) acrylic acid alkyl ester (Aa) and aromatic hydrocarbon group used for the production of the copolymer (A) The respective content ratios of the (meth) acrylic acid alkyl ester (Aa) and the aromatic hydrocarbon group-containing (meth) acrylic acid ester (Ab) in the total with the (meth) acrylic acid ester (Ab) having S corresponds to the content of the copolymer (A) in the (meth) having an acrylic acid alkyl ester (Aa) units and aromatic hydrocarbon group-containing (meth) acrylic acid ester (Ab) units.

  The copolymer (A) of the present invention comprises, in addition to the (meth) acrylic acid alkyl ester (Aa) and the aromatic hydrocarbon group-containing (meth) acrylic acid ester (Ab), units derived from a crosslinking agent and grafting The copolymer is preferably a copolymer having one or both of the units derived from the crosslinking agent, and in the case where the copolymer (A) contains a unit derived from the grafting agent and / or the crosslinking agent, the obtained graft is obtained The effect of further improving the molding appearance and the impact resistance of the thermoplastic resin composition formed by blending the copolymer (B) is exhibited.

Examples of the grafting agent include allyl compounds such as allyl methacrylate, triallyl cyanurate, triallyl isocyanurate and the like. These may use only 1 type and may mix and use 2 or more types.
Examples of the crosslinking agent include dimethacrylate compounds such as ethylene glycol dimethacrylate, propylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, and 1,4-butylene glycol dimethacrylate. These may use only 1 type and may mix and use 2 or more types.

  When a crosslinking agent and / or grafting agent is used, the proportion of units derived from the crosslinking agent and / or grafting agent in the copolymer (A) is obtained by blending the obtained graft copolymer (B) Since the molding appearance and impact resistance of the thermoplastic resin composition are excellent, the (meth) acrylic acid alkyl ester (Aa) unit, the (meth) acrylic acid ester (Ab) unit having an aromatic hydrocarbon group, and the crosslink 0.1-3 mass% is preferable in a total of 100 mass% with the unit derived from an agent and / or the unit derived from a graft crossing agent, 0.2-2 mass% is more preferable.

  In addition, the copolymer (A) is a (meth) acrylic acid alkyl ester (Aa) unit and a (meth) acrylic acid ester (Ab) unit having an aromatic hydrocarbon group, as long as the object of the present invention is not impaired. It may contain other monomer units in addition to the units derived from the crosslinking agent and / or grafting agent which are optionally used. As other monomer units which may be contained in the copolymer (A), (meth) acrylic acid alkyl ester (Aa) and aromatic carbon contained in the vinyl-based monomer mixture (m1) described later Although one or two or more kinds of vinyl monomers other than (meth) acrylic acid ester (Ab) having a hydrogen group may be mentioned, in order to effectively obtain the effect of the present invention, these other vinyl monomers may be used. The content of the monomer unit is preferably 20% by mass or less, particularly 10% by mass or less in 100% by mass of the copolymer (A).

  The method for producing the copolymer (A) is not particularly limited, and the (meth) acrylic acid alkyl ester (Aa), the aromatic hydrocarbon group-containing (meth) acrylic acid ester (Ab), a crosslinking agent and / or a crosslinking agent Or a method of subjecting a mixture containing a graft crossing agent to emulsion polymerization or miniemulsion polymerization is preferable, and the method of miniemulsion polymerization is preferred because the physical properties of the resin composition obtained by blending the resulting graft copolymer (B) are excellent. Particularly preferred.

As a method for producing the copolymer (A) by the emulsion polymerization method, a radical initiator, (meth) acrylic acid alkyl ester (Aa), and (meth) acrylic acid ester (having an aromatic hydrocarbon group) in an aqueous solvent A method of adding Ab) and a crosslinking agent and / or a grafting agent and copolymerizing in the presence of an emulsifying agent can be mentioned.
The method of adding the radical initiator, the (meth) acrylic acid alkyl ester (Aa), the (meth) acrylic acid ester (Ab) having an aromatic hydrocarbon group, and the crosslinking agent and / or grafting agent is all at once. It may be divided or continuous.

  The mini-emulsion polymerization for producing the copolymer (A) is not limited thereto, but, for example, (meth) acrylic acid alkyl ester (Aa) and (meth) acrylic acid having an aromatic hydrocarbon group An ester (Ab), a crosslinking agent and / or a graft crossing agent, a hydrophobic substance, and an initiator are mixed, water and an emulsifier are added to the obtained mixture, and a shear force is applied to obtain a pre-emulsion ( The method may include the steps of producing a miniemulsion), and heating the mixture to the polymerization initiation temperature to polymerize.

  In the step of mini-emulsification, for example, by performing a shearing step by ultrasonic irradiation, the shearing force tears off the monomer to form an emulsifier-covered monomer micro oil droplet. Thereafter, by heating to the polymerization initiation temperature of the initiator, the monomer fine oil droplets are polymerized as it is, and polymer fine particles are obtained. As a method of applying shear force to form a miniemulsion, any known method can be used, and as a high shear device capable of forming a miniemulsion, for example, high pressure pump and There are an emulsifying device comprising an interaction chamber, a device for forming a mini-emulsion by ultrasonic energy and high frequency, and the like. Examples of the emulsifying apparatus comprising a high pressure pump and an interaction chamber include a "pressure type homogenizer" manufactured by SPX Corporation APV, a "microfluidizer" manufactured by Powrex Co., Ltd., etc. Examples of the device to be formed include, but are not limited to, "Sonic Dissembler" manufactured by Fisher Scient, "ULTRONIC HOMOGENIZER" manufactured by Nippon Seiki Co., Ltd., and the like.

  From the viewpoint of workability, stability, manufacturability, etc., the amount of water solvent used in mini-emulsification is such that the solid content concentration of the reaction system after polymerization is about 5 to 50 mass%. It is preferable to set it as about 100-500 mass parts with respect to 100 mass parts of mixtures other than.

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

  Examples of the hydrophobic substance include hydrocarbons having 10 or more carbon atoms, alcohols having 10 or more carbon atoms, hydrophobic polymers having a weight average molecular weight (Mw) of less than 10000, 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 having 10 to 22 carbon atoms), p-alkylstyrene And hydrophobic chain transfer agents, hydrophobic peroxides and the like. One of these may be used alone, or two or more may be mixed and used.

  As the hydrophobic substance, more specifically, hexadecane, octadecane, icosane, liquid paraffin, liquid isoparaffin, paraffin wax, polyethylene wax, polyethylene wax, olive oil, cetyl alcohol, stearyl acrylate, lauryl acrylate, stearyl acrylate, lauryl methacrylate Examples include stearyl methacrylate, polystyrene having a number average molecular weight (Mn) of 500 to 10000, and poly (meth) acrylic acid ester.

  The hydrophobic substance is a total of 100 parts by mass of (meth) acrylic acid alkyl ester (Aa), aromatic hydrocarbon group-containing (meth) acrylic acid ester (Ab), and crosslinking agent and / or grafting agent. Preferably, 0.1 to 10 parts by mass, more preferably 1 to 3 parts by mass is used in terms of particle diameter control of the copolymer (A).

  Examples of the emulsifier used in producing the copolymer (A) of the present invention include carboxylic acids such as oleic acid, palmitic acid, stearic acid, alkali metal salts of rosin acid, alkali metal salts of alkenyl succinic acid, etc. Emulsifiers, alkyl sulfate esters, sodium alkylbenzene sulfonates, sodium alkyl sulfosuccinates, polyoxyethylene nonyl phenyl ether sulfate sodium esters, etc., using known emulsifiers alone or in combination of two or more, such as anionic emulsifiers selected from sodium and the like can do.

  The amount of the emulsifier added is 100 parts by mass in total of (meth) acrylic acid alkyl ester (Aa), aromatic hydrocarbon group-containing (meth) acrylic acid ester (Ab), and crosslinking agent and / or grafting agent On the other hand, 0.01 to 1.0 parts by mass is preferable, and further preferably 0.05 to 0.5 parts by mass is preferable in terms of particle diameter control of the copolymer (A).

  The initiator used for the production of the copolymer (A) is a radical polymerization initiator for radical polymerization, and the type thereof is not particularly limited. For example, azo polymerization initiator, photopolymerization initiator, inorganic peroxide Substances, organic peroxides, redox initiators in which organic peroxides, transition metals and reducing agents are combined, and the like. Among these, an azo polymerization initiator capable of initiating polymerization by heating, an inorganic peroxide, an organic peroxide, and a redox initiator are preferable. These may be used alone or in combination of two or more.

  As an azo polymerization initiator, for example, 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-methyl propionate), dimethyl 1,1′-azobis (1-cyclohexylene carboxylate ), 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 (2,2, 4, 4- trimethyl pentane) etc. are mentioned.

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

  Examples of the organic peroxide include peroxy ester compounds, and specific examples thereof 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-ethylhexano Aate, 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- Butylperoxy 2-ethylhexyl monocarbonate, t-hexylperoxybenzoate, 2,5-dimethyl-2,5-bis (benzoylperoxy) hexane, t-butylperoxyacetate, t-butylperoxy-m-toluol Nzoate, 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) 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, dicumyl peroxide, 2, 5- Methyl-2,5-bis (t-butylperoxy) hexane, t-butylcumyl peroxide, 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-butyl) Peroxy) valerate, t-butyl 2-ethylhexaneperoxy acid, dibenzoyl peroxide, paramenthane hydroperoxide, t-butyl peroxybenzoate, etc. are mentioned It is.

  The redox initiator is preferably a combination of an organic peroxide and 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 sulfate (rongalite), ferrous sulfate, and disodium ethylenediaminetetraacetate And the like.

  Among these, the redox initiator and the organic peroxide are preferable as the initiator, and the organic peroxide is particularly preferable.

  The addition amount of the initiator is a total of 100 mass of (meth) acrylic acid alkyl ester (Aa), (meth) acrylic acid ester (Ab) having an aromatic hydrocarbon group, and a crosslinking agent and / or a grafting agent. The amount is usually 5 parts by mass or less, preferably 3 parts by mass or less, for example, 0.001 to 3 parts by mass with respect to 1 part.

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

The average particle diameter of the copolymer (A) of the present invention dispersed in the aqueous dispersion is excellent in the physical properties of a molded article made of a thermoplastic resin composition obtained by blending the graft copolymer (B) to be obtained Therefore, 50 to 800 nm is preferable, 100 to 600 nm is more preferable, and 250 to 450 nm is more preferable.
The method of controlling the average particle size of the copolymer (A) is not particularly limited, but includes a method of adjusting the type or amount of the emulsifier.
In addition, the average particle diameter of a copolymer (A) is a volume average particle diameter measured by the method described in the term of the below-mentioned Example here.

In addition, the degree of swelling of the copolymer (A) of the present invention is excellent in the impact resistance and the molding appearance of the thermoplastic resin composition obtained by blending the obtained graft copolymer (B), and particularly the injection of the molding appearance In order to reduce the speed dependency, 2 to 15 times is preferable, and 4 to 10 times is more preferable.
The degree of swelling of the copolymer (A) is measured by the method described in the section of Examples described later.

<Graft copolymer (B)>
The graft copolymer (B) of the present invention is obtained by graft polymerization of a vinyl monomer mixture (m1) in the presence of the copolymer (A).

  The vinyl-based monomer mixture (m1) is an aromatic vinyl-based monomer and a vinyl cyanide-based monomer because the physical properties of the thermoplastic resin composition obtained by blending the obtained graft copolymer (B) are excellent. It is preferred to include a mer.

  Examples of the aromatic vinyl monomer contained in the vinyl monomer mixture (m1) include styrene, α-methylstyrene, o-, m- or p-methylstyrene, vinylxylene, p-t-butyl Styrene, ethyl styrene and the like can be mentioned, and these can be used alone or in combination of two or more. The structure of the aromatic vinyl monomer is not particularly limited, but the thermoplastic resin composition should have the same structure as the aromatic vinyl monomer contained in the vinyl monomer mixture (m2) described later. And it is preferable at the point of the impact resistance of the molded article, and a molding external appearance.

  Thermoplastic resin obtained by blending the obtained graft copolymer (B) that the content of the aromatic vinyl monomer contained in the vinyl monomer mixture (m1) is 40 to 90 mass% It is preferable in the point of the impact resistance of a composition and its molded article, and a molding appearance, and it is more preferable that it is 60-80 mass%.

  Examples of the vinyl cyanide-based monomer contained in the vinyl-based monomer mixture (m1) include acrylonitrile and methacrylonitrile, and one or more of these can be used. The structure of the vinyl cyanide-based monomer is not particularly limited, but the thermoplastic resin obtained has the same structure as the vinyl cyanide-based monomer contained in the vinyl-based monomer mixture (m2) described later. It is preferable in the point of the impact resistance of a composition and its molded article, and a shaping | molding external appearance.

  Thermoplastic resin obtained by blending the obtained graft copolymer (B) that the content of the vinyl cyanide monomer contained in the vinyl monomer mixture (m1) is 10 to 60% by mass It is preferable in the point of the impact resistance of a composition and its molded article, and a molding appearance, and it is more preferable that it is 20-40 mass%.

The vinyl-based monomer mixture (m1) may contain the above-mentioned aromatic vinyl-based monomer and vinyl cyanide-based monomer, and other vinyl-based monomers copolymerizable therewith.
The content of the other copolymerizable vinyl monomer in the vinyl monomer mixture (m1) is preferably 20% by mass or less, and particularly preferably 10% by mass or less.
As another vinyl monomer, for example, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, i-propyl methacrylate, n-butyl methacrylate, i-butyl methacrylate, t-butyl methacrylate, Methacrylates such as amyl methacrylate, isoamyl methacrylate, octyl methacrylate, 2-ethylhexyl methacrylate, decyl methacrylate, lauryl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, phenyl methacrylate and the like, N-methylmaleimide, N-cyclopropyl such as N-ethyl maleimide, N-n-propyl maleimide, N-i-propyl maleimide, N-n-butyl maleimide, N-i-butyl maleimide, N-tert-butyl maleimide, N-cyclohexyl maleimide, etc. N-aryl maleimides such as alkyl maleimide, N-phenyl maleimide, N-alkyl substituted phenyl maleimide, N-chlorophenyl maleimide, maleimide compounds such as N-aralkyl maleimide, methyl acrylate, ethyl acrylate, propyl acrylate, acrylic And acrylic acid esters such as butyl acid. These may use only 1 type and may mix and use 2 or more types.

In the graft copolymer (B), a vinyl monomer mixture (m1) is graft polymerized with the copolymer (A).
The impact resistance and molding appearance of the thermoplastic resin composition obtained by compounding the obtained graft copolymer (B) are excellent, and in particular, the injection speed dependency of the molding appearance can be reduced, so that the graft copolymer (B) The copolymer (A) and the vinyl-based monomer mixture (m1) used for the production contain 50 to 80% by mass of the copolymer (A) in 100% by mass of the graft copolymer (B), and a single monomer amount It is preferable that a body mixture (m1) is 20-50 mass%.

  Further, the graft copolymer (B) is excellent in the impact resistance and the molding appearance of the thermoplastic resin composition formed by blending the obtained graft copolymer (B), so that the graft ratio is 25 to 100%. Is preferred. The grafting ratio of the graft copolymer (B) is measured by the method described in the section of Examples described later.

  The graft copolymer (B) is produced by a known method such as bulk polymerization, solution polymerization, bulk suspension polymerization, suspension polymerization, emulsion polymerization, etc. The emulsion polymerization method is preferred because the impact resistance of the thermoplastic resin composition formed by compounding (ii) is good.

As a method of emulsion graft polymerization, there is a method of radically polymerizing a vinyl monomer mixture (m1) collectively, continuously or intermittently in the presence of an emulsion of the copolymer (A). It can be mentioned. In addition, at the time of graft polymerization, a chain transfer agent is used for the purpose of adjusting the molecular weight of the graft polymer (B) and controlling the grafting rate, and known inorganic electrolytes and the like for the purpose of adjusting the viscosity and pH of the latex. You may use In the emulsion graft polymerization, various emulsifiers and radical initiators can be used as needed.
There are no particular restrictions on the type and amount of the emulsifier and radical initiator added. Moreover, as an emulsifier and a radical initiator, the emulsifier and radical initiator which were illustrated previously in description of a copolymer (A) are mentioned.

  As a method for recovering the graft copolymer (B) from the aqueous dispersion of the graft copolymer (B), (i) aqueous dispersion of the graft copolymer (B) in hot water in which a coagulant is dissolved Method to collect by charging body and coagulating in slurry state (wet method), (ii) Semi-directly by spraying aqueous dispersion of graft copolymer (B) into heating atmosphere The method (spray dry method) etc. which collect | recover a graft copolymer (B) are mentioned.

  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 according to the emulsifier used in the polymerization. That is, when only carboxylic acid soaps such as fatty acid soaps and rosin acid soaps are used, any coagulant may be used. In the case where an emulsifier exhibiting stable emulsifying power even in an acidic region such as sodium dodecylbenzene sulfonate is contained, it is necessary to use a metal salt.

  As a method of obtaining the graft copolymer (B) in a dry state from the graft copolymer (B) in a slurry state, after the emulsifier residue remaining in the slurry is eluted in water by (i) washing, the slurry is A method of dewatering with a centrifugal dehydrator or a press dehydrator and further drying with a flash dryer etc., (ii) A method of simultaneously carrying out dewatering and drying with a squeeze dehydrator, an extruder etc, etc. may be mentioned. After drying, the graft copolymer (B) is obtained in the form of powder or particles. The graft copolymer (B) discharged from the press dehydrator or extruder can also be sent directly to the extruder or molding machine for producing the thermoplastic resin composition.

[Copolymer (C)]
The copolymer (C) is obtained by polymerizing a vinyl monomer mixture (m2).

  The vinyl-based monomer mixture (m2) has the same composition as the vinyl-based monomer mixture (m1) described above because the physical properties of the thermoplastic resin composition obtained by blending the copolymer (C) are excellent. Is preferable, and it is preferable to contain an aromatic vinyl monomer and a vinyl cyanide monomer.

  Examples of the aromatic vinyl monomer contained in the vinyl monomer mixture (m2) include styrene, α-methylstyrene, o-, m- or p-methylstyrene, vinylxylene, p-t-butyl Styrene, ethyl styrene and the like can be mentioned, and these can be used alone or in combination of two or more. The structure of the aromatic vinyl monomer is not particularly limited, but the thermoplastic resin obtained has the same structure as the aromatic vinyl monomer contained in the above-mentioned vinyl monomer mixture (m1). It is preferable in the point of the impact resistance of a composition and its molded article, and a shaping | molding external appearance.

  The content of the aromatic vinyl monomer contained in the vinyl monomer mixture (m2) is 40 to 90% by mass, the resulting thermoplastic resin composition and the impact resistance of the molded article thereof, and the molding thereof It is preferable in the point of an external appearance, and it is more preferable that it is 60-80 mass%.

  Examples of the vinyl cyanide-based monomer contained in the vinyl-based monomer mixture (m2) include acrylonitrile and methacrylonitrile, and one or more of these can be used. Although there is no restriction | limiting in particular in the structure of a vinyl cyanide type monomer, It is a thermoplastic resin obtained that it is the same structure as the vinyl cyanide type monomer contained in the above-mentioned vinyl type monomer mixture (m1) It is preferable in the point of the impact resistance of a composition and its molded article, and a shaping | molding external appearance.

  The content of the vinyl cyanide-based monomer contained in the vinyl-based monomer mixture (m2) is 10 to 60% by mass, the resulting thermoplastic resin composition and the impact resistance of the molded article thereof, and the molding thereof It is preferable in the point of an external appearance, and it is more preferable that it is 20-40 mass%.

The vinyl-based monomer mixture (m2) may contain the above-mentioned aromatic vinyl-based monomer and vinyl cyanide-based monomer, and other vinyl-based monomers copolymerizable therewith.
The content of the other copolymerizable vinyl monomer in the vinyl monomer mixture (m2) is preferably 20% by mass or less, particularly preferably 10% by mass or less.
Examples of other vinyl monomers include those exemplified as other vinyl monomers which may be contained in the vinyl monomer mixture (m1), and these other vinyl monomers are , 1 type can be used individually or in combination of 2 or more types.

The mass average molecular weight of the copolymer (C) is not particularly limited, but is preferably in the range of 10,000 to 300,000, and particularly preferably in the range of 50,000 to 200,000. If the mass average molecular weight of the copolymer (C) is in the above range, the flowability and impact resistance of the thermoplastic resin composition to be obtained will be excellent, and furthermore, the injection speed dependency of the molding appearance can be reduced.
In addition, the mass mean molecular weight of a copolymer (C) is measured by the method as described in the term of the below-mentioned Example.

  It does not restrict | limit especially as a manufacturing method of a copolymer (C), Well-known methods, such as emulsion polymerization, suspension polymerization, block polymerization, solution polymerization, are mentioned. From the viewpoint of the heat resistance of the thermoplastic resin composition to be obtained, suspension polymerization and bulk polymerization are preferred.

  Although there is no restriction | limiting in particular in the polymerization initiator used at the time of manufacture of a copolymer (C), For example, organic peroxides are mentioned.

  A chain transfer agent can be used to adjust the molecular weight of the copolymer (C) during the production of the copolymer (C). Although there is no restriction | limiting in particular in a chain transfer agent, A mercaptans, (alpha) -methylstyrene dimer, terpenes etc. are mentioned.

[Thermoplastic resin composition]
The thermoplastic resin composition of the present invention contains the above-mentioned graft copolymer (B) of the present invention, and preferably, the graft copolymer (B) of the present invention and the above-mentioned copolymer (C) And.

  The content of the graft polymer (B) of the present invention in the thermoplastic resin composition of the present invention is 10 to 10% when the total of the graft copolymer (B) and the copolymer (C) is 100% by mass. The content is preferably 40% by mass, and the content of the copolymer (C) is preferably 60 to 90% by mass. When the content of the graft polymer (B) and the copolymer (C) is in the above range, the impact resistance and molded appearance of the thermoplastic resin composition and its molded article become excellent, and further, the molded appearance The injection speed dependency can be reduced.

  The thermoplastic resin composition of the present invention may optionally contain other thermoplastic resins. The other thermoplastic resin is not particularly limited, and examples thereof include polycarbonate resin, polybutylene terephthalate (PBT resin), polyethylene terephthalate (PET resin), polyvinyl chloride, polystyrene, polyacetal resin, modified polyphenylene ether (modified PPE resin), Ethylene-vinyl acetate copolymer, polyarylate, liquid crystal polyester resin, polyethylene resin, polypropylene resin, fluorine resin, polyamide resin (nylon) and the like can be mentioned. These may use only 1 type and may mix and use 2 or more types.

  In the thermoplastic resin composition of the present invention, other additives commonly used at the time of production (at the time of mixing) of the thermoplastic resin composition and at the time of molding as long as the physical properties of the thermoplastic resin composition and its molded articles are not impaired. For example, lubricants, pigments, dyes, fillers (carbon black, silica, titanium oxide, etc.), heat resisting agents, oxidation deterioration inhibitors, weathering agents, mold release agents, plasticizers, antistatic agents, etc. can be blended. .

  The thermoplastic resin composition of the present invention can be produced by a known method using a known device. For example, there is a melt mixing method as a general method, and as an apparatus used in this method, an extruder, a Banbury mixer, a roller, a kneader, etc. may be mentioned. Either a batch system or a continuous system may be adopted for mixing. Moreover, there is no restriction | limiting in particular also in the order of mixing of each component, etc., and all the components should just be 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 an injection molding method, an injection compression molding machine method, an extrusion method, a blow molding method, a vacuum molding method, a pressure forming method, a calendar molding method and an inflation molding method. Among them, injection molding method and injection compression molding method are preferable because they are excellent in mass productivity and can obtain molded products with high dimensional accuracy.

[Use]
The thermoplastic resin composition of the present invention and the application of the molded article thereof are not particularly limited, but the thermoplastic resin composition of the present invention and the molded article thereof are excellent in impact resistance and excellent in molding appearance and flowability. Due to the small injection speed dependency of the molded appearance, it is useful in a wide range of fields such as OA, home electric appliances, vehicles and ships, housing related fields such as furniture and building materials, sanitary fields, sundries, sundries, stationery, toys and sports goods. It is.

EXAMPLES Hereinafter, the present invention will be more specifically described by way of examples and comparative examples, but the present invention is not limited to the following examples at all unless it exceeds the gist thereof.
In the following, “parts” means “parts by mass”, and “%” means “mass%”.

  Various measurement and evaluation methods in the following examples and comparative examples are as follows.

<Volume Average Particle Size of Copolymer (A)>
The volume average particle diameter of the copolymer (A) dispersed in the aqueous dispersion was measured using ion exchange water as a measurement solvent using Microtrac (“Nanotrac 150” manufactured by Nikkiso Co., Ltd.).

<Swelling degree of copolymer (A)>
The copolymer (A) was dried at 80 ° C. for 24 hours, and then vacuum dried at 80 ° C. for 24 hours to form a dry product of the film-like copolymer (A). The weight of the obtained dried product is W1. The dried product was immersed in acetone at normal temperature for 12 hours, then filtered through a 200 mesh wire mesh, and the residue was weighed. Let W2 be the weight of the residual. The residue was then vacuum dried at ambient temperature for 24 hours. Let W3 be the weight of the residual dry product after vacuum drying. The degree of swelling of the copolymer (A) is calculated by the following formula (1).
Degree of swelling (%) = (W2 / W3) × 100 (1)

<Grafting rate of graft copolymer (B)>
1 g of the graft copolymer (B) is added to 80 mL of acetone, and the mixture is heated under reflux at 65 to 70 ° C. for 3 hours, and the obtained suspended acetone solution is used as a centrifuge (“CR21E” manufactured by Hitachi Koki Co., Ltd.) The mixture was centrifuged at 14,000 rpm for 30 minutes to separate the precipitated component (acetone-insoluble component) and the acetone solution (acetone-soluble component). And the precipitation component (acetone insoluble component) was dried, the mass (Y (g)) was measured, and the graft ratio was computed by following formula (2). In the formula (2), Y is the mass (g) of the acetone insoluble component of the graft copolymer (B), and X is the total mass (g) of the graft copolymer (B) used in obtaining Y, The rubber fraction is the solid concentration in the aqueous dispersion of the copolymer (A) used for the production of the graft copolymer (B).
Graft ratio (mass%) = {(Y-X × rubber fraction) / X × rubber fraction}
× 100 (2)

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

[Production of copolymer (A)]
<Production of Copolymer (A-1)>
The copolymer (A-1) was manufactured by the following mixing | blending.
[Blending]
N-butyl acrylate 54 parts 2-phenoxyethyl acrylate 6 parts allyl methacrylate 0.24 parts 1,3-butylene glycol dimethacrylate 0.12 parts liquid paraffin (LP) 0.6 parts alkenyl potassium succinate (ASK) 0.20 parts dilauroyl peroxide 0.6 parts ion exchanged water 406 parts

N-Butyl acrylate, 2-phenoxyethyl acrylate, liquid paraffin, allyl methacrylate, dilauroyl peroxide, ion-exchanged water, alkenylsuccinic acid in a reactor equipped with a reagent injection container, a condenser, a jacket heater and a stirrer A pre-emulsion was obtained by charging dipotassium acid and performing ultrasonic treatment with an amplitude of 35 μm for 20 minutes at room temperature using ULTRASONIC HOMOGENIZER US-600 manufactured by Nippon Seiki Seisakusho Co., Ltd. The volume average particle diameter of the obtained latex was 350 nm.
The pre-emulsion was heated to 60 ° C. to initiate radical polymerization. The liquid temperature rose to 78 ° C. due to the polymerization. The polymerization was completed by maintaining at 75 ° C. for 30 minutes to obtain a copolymer (A-1) dispersed in an aqueous dispersion having a volume average particle diameter of 300 nm.

<Production of Copolymers (A-2) to (A-7)>
It is dispersed in an aqueous dispersion in the same manner as the copolymer (A-1) except that the amounts of n-butyl acrylate, 2-phenoxyethyl acrylate and dipotassium alkenylsuccinate are changed as shown in Table 1A. Copolymers (A-2) to (A-7) were obtained.

<Production of Copolymer (A-8)>
A copolymer (A-8) dispersed in an aqueous dispersion is obtained in the same manner as the copolymer (A-1) except that benzyl acrylate is used instead of 2-phenoxyethyl acrylate. The

<Production of Copolymer (A-9)>
0.27 parts of dipotassium alkenyl succinate, 175 parts of ion exchange water, 48 parts of n-butyl acrylate, 12 parts of 2-phenoxyethyl acrylate, 0.24 parts of allyl methacrylate, 1,3-butylene glycol dimethacrylate 0. 2 A mixture of 12 parts and 0.1 part of t-butyl hydroperoxide was charged to the reactor. The reactor was purged with nitrogen by passing a nitrogen stream through the reactor, and the temperature was raised to 60.degree. When the internal temperature reaches 50 ° C., add an aqueous solution consisting of 0.00015 parts of ferrous sulfate, 0.00045 parts of ethylenediaminetetraacetic acid disodium salt, 0.24 parts of Rongalite, and 5 parts of ion-exchanged water The polymerization was initiated and the internal temperature was raised to 75 ° C. This state was further maintained for 1 hour to obtain a rubbery polymer (A-9) dispersed in an aqueous dispersion having a volume average particle diameter of 0.30 μm.

<Production of Copolymers (A-10) to (A-12)>
An aqueous dispersion in the same manner as the copolymer (A-1) except that the amount of n-butyl acrylate and dipotassium alkenyl succinate was as shown in Table 1B without using 2-phenoxyethyl acrylate The copolymers (A-10) to (A-12) dispersed in the above were obtained.

<Production of Copolymer (A-13)>
A copolymer (A-13) dispersed in an aqueous dispersion was obtained in the same manner as the copolymer (A-1) except that styrene was used instead of 2-phenoxyethyl acrylate.

<Production of Copolymer (A-14)>
145 parts of ion-exchanged water (hereinafter, simply abbreviated as water), 1.0 part of potassium rosin acid, 1.0 part of potassium oleate, sodium hydroxide in a stainless steel autoclave (hereinafter, abbreviated as SUS autoclave) After charging 0.06 parts, 0.4 parts of sodium sulfate and 0.3 parts of t-dodecyl mercaptan, and substituting with nitrogen, 125 parts of 1,3-butadiene was charged and the temperature was raised to 60 ° C.
Then, an aqueous solution in which 0.3 part of potassium persulfate was dissolved in 5 parts of water was injected to initiate polymerization. During the polymerization, the polymerization temperature was adjusted to 65 ° C., and after 12 hours, unreacted 1,3-butadiene was recovered when the internal pressure reached 4.5 kg / cm ² (gauge pressure). Thereafter, the internal temperature was maintained at 80 ° C. and held for 1 hour, to obtain a butadiene rubber latex having a volume average particle diameter of 250 nm and a solid content of 41%.

  Charge 20 parts of a butadiene rubber latex in terms of solid content into a 5-liter glass reactor, add 1.0 part of dipotassium alkenyl succinate and 150 parts of water, carry out nitrogen substitution, and raise the internal temperature to 70 ° C. It warmed. To this is added an aqueous solution of 0.12 parts of potassium persulfate in 10 parts of water, followed by 79.5 parts of n-butyl acrylate, 0.33 parts of allyl methacrylate, 1,3 A monomer mixture consisting of 0.17 parts of butylene glycol dimethacrylate was dropped continuously over 2 hours. After completion of the dropwise addition, the internal temperature is raised to 80 ° C. and held for 1 hour, and a copolymer (A-) comprising an butadiene rubber and an acrylic rubber dispersed in an aqueous dispersion having a volume average particle diameter of 300 nm 14) I got it.

  The swelling degree and volume average particle diameter of the copolymers (A-1) to (A-14) are shown in Tables 1A and 1B.

[Production of Graft Copolymer (B)]
<Production of Graft Copolymer (B-1)>
After the production of the copolymer (A-1), 60 parts (as solid content) of the copolymer (A-1) was added to ferrous sulfate 0. 2 while maintaining the internal temperature of the reactor at 75 ° C. An aqueous solution consisting of 001 parts, 0.003 parts of ethylenediaminetetraacetic acid disodium salt, 0.3 parts of Rongalite, and 5 parts of ion-exchanged water is added, and then 0.65 parts of dipotassium alkenyl succinate and 10 parts of ion-exchanged water An aqueous solution consisting of was added. Thereafter, a mixed solution consisting of 13.6 parts of acrylonitrile, 26.4 parts of styrene and 0.18 parts of t-butyl hydroperoxide as a vinyl monomer mixture (m1) is dropped over 1 hour and 30 minutes to carry out graft polymerization. I did.
After completion of the dropwise addition, the internal temperature is maintained at 75 ° C. for 10 minutes, followed by cooling, and when the internal temperature reaches 60 ° C., 0.2 parts of an antioxidant (Antage W500 manufactured by Yoshitomi Pharmaceutical Co., Ltd.) and alkenylsuccinics An aqueous solution of 0.2 parts of dipotassium acid dissolved in 5 parts of ion-exchanged water was added. Then, the aqueous dispersion of the reaction product was coagulated with an aqueous sulfuric acid solution, washed with water, and dried to obtain a graft copolymer (B-1). The grafting ratio of the graft copolymer (B-1) was 40%.

<Production of Graft Copolymers (B-2) to (B-14)>
Graft copolymers (B-2) to (B-14) were prepared in the same manner as in graft copolymer (B-1) except that the type of copolymer (A) used was changed as shown in Table 2. Got).

  The grafting rates of the graft copolymers (B-2) to (B-14) were as shown in Table 2.

[Production of copolymer (C)]
<Production of Copolymer (C-1)>
150 parts of ion-exchanged water, a mixture of 34 parts of acrylonitrile and 66 parts of styrene as a vinyl monomer mixture (m2) in a pressure resistant reaction vessel, 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 alkenyl succinate were charged, the internal temperature was raised to 75 ° C., and reaction was performed for 3 hours. Thereafter, the temperature was raised to 90 ° C., and the reaction was completed by holding for 60 minutes. The contents were washed with a centrifugal dehydrator, dried repeatedly, and dried to obtain a copolymer (C-1) having a mass average molecular weight of 100,000.

[Examples 1 to 9, Comparative Examples 1 to 7]
Each component is mixed by the composition (mass part) shown in Table 3, 0.8 parts of carbon black is further mixed there, and it uses 240 mm of 30 mm diameter vacuum-vented twin screw extruder ("PCM30" by Ikegai Co., Ltd.) It melt-kneaded at (degreeC), and obtained the pellet-like thermoplastic resin composition. The melt volume rate of the obtained thermoplastic resin composition was evaluated by the following method. Moreover, the molding appearance and impact resistance were evaluated by the following method about the molded article which injection-molded the obtained thermoplastic resin composition.
The evaluation results are shown in Table 3.

[Each evaluation method]
<Measurement of melt volume rate (MVR)>
The thermoplastic resin composition was measured at 220 ° C. according to the ISO 1133 standard. In addition, MVR becomes a standard of the fluidity of a thermoplastic resin composition.

<Injection molding 1>
Pellets of the thermoplastic resin composition obtained by melt-kneading are subjected to an injection molding machine (“IS55FP-1.5A” manufactured by Toshiba Machine Co., Ltd.) at a cylinder temperature of 200 to 270 ° C., a mold temperature of 60 ° C., and an injection ratio of 25 g / sec A molded product of 80 mm in length, 10 mm in width and 4 mm in thickness was molded under the conditions of 2. and used as a molded product for Charpy impact test (a molded product (Ma1)).

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

<Injection molding 3>
Pellets of the thermoplastic resin composition obtained by melt-kneading are subjected to an injection molding machine (“IS55FP-1.5A” manufactured by Toshiba Machine Co., Ltd.) at a cylinder temperature of 200 to 270 ° C., a mold temperature of 60 ° C., and an injection rate of 128 g / sec A molded product of 100 mm in length, 100 mm in width, and 3 mm in thickness was molded under the conditions of 2. and used as a high-speed injection molded product (high-speed injection molded product (Ma3)) for appearance evaluation.

<Appearance evaluation I>
The lightness L ^* of the molded product (Ma2) was measured by the SCE method using a spectrocolorimeter ("CM-500d" manufactured by Konica Minolta Optips). The measured L ^* is taken as "L ^* (ma)". The lower the L ^{*, the} blacker and the better the appearance.

<Appearance evaluation II>
The lightness L ^* of the high-speed injection molded product (Ma3) was measured by the SCE method using a spectrocolorimeter ("CM-500d" manufactured by Konica Minolta Optips Co., Ltd.). Let L ^* measured be "L ^* (mb)". The lower the L ^{*, the} blacker and the better the appearance.
When molding is performed under conditions of high injection speed, the rubber component in the resin is oriented to cause whitening and bronzing, resulting in an increase in L ^* . Therefore, the molding appearance under the condition of high injection speed is important.

<Appearance evaluation III (injection speed dependency evaluation of appearance)>
ΔL ^* = was calculated ΔL ^* than ^{(L * (mb) -L *} (ma)) 2 of the formula. The smaller the ΔL ^* , the smaller the injection speed dependency of the appearance. Generally, in molded articles such as vehicle parts, the injection speed varies depending on the part location. Therefore, in the case of a resin having a large injection speed dependency, appearance defects occur such as color unevenness occurring on the surface of the part during molding.

<Evaluation of impact resistance: Charpy impact test>
The molded article (Ma1) was subjected to a Charpy impact test (notched) at 23 ° C. in accordance with the ISO 179 standard to measure the Charpy impact strength.

As shown in Examples 1 to 9 of Table 3, according to each example, a thermoplastic resin composition and a molded article excellent in impact resistance, flowability, and molding appearance were obtained. In addition, with the thermoplastic resin compositions of Examples 1 to 9, the injection speed dependency of the molding appearance is also small.
On the other hand, the thermoplastic resin compositions and molded articles obtained in Comparative Examples 1 to 7 were significantly inferior in any of impact resistance, flowability, and appearance, and the injection speed dependency of the molded appearance was also large.

Claims (13)

  Graft polymerization of vinyl monomer mixture (m1) onto copolymer (A) of (meth) acrylic acid alkyl ester (Aa) and (meth) acrylic acid ester (Ab) having aromatic hydrocarbon group And a graft copolymer (B).   (Meth) acrylic acid in a total of 100% by mass of (meth) acrylic acid alkyl ester (Aa) units in the copolymer (A) and (meth) acrylic acid ester (Ab) units having an aromatic hydrocarbon group The content of the alkyl ester (Aa) unit is 30 to 95% by mass, and the content of the (meth) acrylic acid ester (Ab) unit having an aromatic hydrocarbon group is 5 to 70% by mass. Graft copolymer (B) as described.   The copolymer (A) comprises a (meth) acrylic acid alkyl ester (Aa) unit, a (meth) acrylic acid ester (Ab) unit having an aromatic hydrocarbon group, and a unit and / or graft derived from a crosslinking agent The graft copolymer (B) according to claim 1 or 2, comprising a unit derived from a cross-linking agent.   The proportion of units derived from the crosslinking agent and / or grafting agent in the copolymer (A) is (meth) acrylic acid alkyl ester (Aa) units and (meth) acrylic acid ester having an aromatic hydrocarbon group The graft copolymer according to claim 3, which is 0.1 to 3% by mass in a total of 100% by mass of the (Ab) unit and the unit derived from the crosslinking agent and / or the unit derived from the graft crossing agent. (B).   The copolymer (A) comprises (meth) acrylic acid alkyl ester (Aa), an aromatic hydrocarbon group-containing (meth) acrylic acid ester (Ab), a crosslinking agent and / or a grafting agent, and hydrophobicity. The graft copolymer (B) according to claim 3 or 4, which is a miniemulsion polymer of a mixture of a substance and an initiator.   The graft copolymer (B) according to any one of claims 1 to 5, wherein the volume average particle diameter of the copolymer (A) is 50 to 800 nm, and the degree of swelling is 2 to 15 times.   Content rate of the vinyl aromatic monomer contained in the vinyl monomer mixture (m1), wherein the vinyl monomer mixture (m1) contains the aromatic vinyl monomer and the vinyl cyanide monomer The graft copolymer (B) according to any one of claims 1 to 6, wherein the content of the vinyl cyanide monomer is 10 to 60% by mass at 40 to 90% by mass.   The proportion of the copolymer (A) is 50 to 80% by mass with respect to the total 100% by mass of the copolymer (A) and the vinyl monomer mixture (m1), and the proportion of the vinyl monomer mixture (m1) The graft copolymer (B) according to any one of claims 1 to 7, wherein the graft ratio is 20 to 50% by mass, and the graft ratio is 25 to 100%.   A thermoplastic resin composition comprising the graft copolymer (B) according to any one of claims 1 to 8.   The thermoplastic resin composition according to claim 9, comprising a graft copolymer (B) and a copolymer (C) which is a polymerization reaction product of a vinyl monomer mixture (m2).   The vinyl-based monomer mixture (m1) contains an aromatic vinyl-based monomer and a vinyl cyanide-based monomer, and the vinyl-based monomer mixture (m2) is included in the vinyl-based monomer mixture (m1) An aromatic vinyl monomer having the same structure as the aromatic vinyl monomer and a vinyl cyanide monomer having the same structure as the vinyl cyanide monomer contained in the vinyl monomer mixture (m1) The thermoplastic resin composition according to claim 10, comprising   10 to 40 mass% of the graft copolymer (B) and 60 to 90 mass% of the copolymer (C) in the total 100 mass% of the graft copolymer (B) and the copolymer (C), The thermoplastic resin composition according to claim 10 or 11.   A molded article formed by molding the thermoplastic resin composition according to any one of claims 9 to 12.