HK1188231B - Acrylic rubber-based graft copolymer and thermoplastic resin composition - Google Patents

Abstract

[Problem] To provide an acrylic rubber-based graft copolymer capable of providing a thermoplastic resin composition of which impact resistance, stiffness, and external appearance are all excellent, and to provide a thermoplastic resin composition including the acrylic rubber-based graft copolymer. [Solution] An acrylic rubber-based graft copolymer that is a graft copolymer formed by graft polymerization of a vinyl monomer in the presence of a rubber polymer including acrylic ester-based monomer units and polyfunctional monomer units, wherein the total volume of the polyfunctional monomer units in the rubber polymer is 0.3-3 parts by mass with respect to 100 parts by mass of the acrylic ester-based monomer units, and 30-95% by mass of polyfunctional monomer units having two unsaturated bonds and 5-70% by mass of polyfunctional monomer units having three unsaturated bonds are included in the total volume of 100% by mass of the polyfunctional monomer units. A thermoplastic resin composition including the acrylic rubber-based graft copolymer.

Description

Acrylic rubber-based graft copolymer and thermoplastic resin composition

Technical Field

The present invention relates to an acrylic rubber-based graft copolymer useful as various industrial materials, and a thermoplastic resin composition and a thermoplastic resin molded article using the same.

Background

Conventionally, a graft polymer obtained by graft polymerizing a rubber polymer with a monomer which imparts compatibility with a thermoplastic resin (for example, a styrene-acrylonitrile copolymer resin, an α -methylstyrene-acrylonitrile copolymer resin, a styrene-acrylonitrile-phenylmaleimide copolymer resin, etc.) has been blended with the thermoplastic resin, and has been widely used in society as a material which imparts impact resistance, as represented by an ABS resin, an ASA resin, etc. Among these, ASA resins using a component such as an alkyl (meth) acrylate rubber as a saturated rubber among rubber polymers have a characteristic of good weather resistance.

On the other hand, ASA resins have the following disadvantages: the colored molded article has poor appearance or reduced impact resistance due to reduced color development or the like. In order to improve the balance between poor appearance and impact resistance, ASA resins comprising as a constituent component an acrylic ester-based rubbery polymer composed of a combination of rubber particles having different particle size distributions have been proposed (patent documents 1 to 3).

In order to compensate for the drawbacks of ASA resins, there is proposed a thermoplastic resin composition containing an ASA resin in combination with an AES resin containing an ethylene-propylene rubber component (patent document 4).

However, the above thermoplastic resin compositions are insufficient in impact resistance, rigidity, weather resistance and pigment colorability, and cannot sufficiently meet the recent strict requirements.

Documents of the prior art

Patent document

Patent document 1: japanese laid-open patent publication No. 59-232138

Patent document 2: japanese laid-open patent publication No. H04-225051

Patent document 3: japanese laid-open patent publication No. H08-134312

Patent document 4: japanese patent laid-open publication No. 2004-346187

Disclosure of Invention

Problems to be solved by the invention

The present invention has been made in view of the above circumstances, and an object thereof is to provide an acrylic rubber-based graft copolymer which is excellent in impact resistance, rigidity and appearance and can provide a thermoplastic resin composition excellent in impact resistance, rigidity and appearance, and a thermoplastic resin composition containing the acrylic rubber-based graft copolymer.

Means for solving the problems

The present inventors have intensively studied to solve the above problems, and as a result, they have found that an acrylic rubber graft copolymer obtained by polymerizing a vinyl monomer in a rubber polymer obtained by using a specific polyfunctional monomer in combination can solve the above problems in the production of a rubber polymer containing an acrylate monomer unit.

The present invention has been completed based on such a technical idea, and the gist thereof is as follows.

[1] An acrylic rubber graft copolymer obtained by graft-polymerizing a vinyl monomer in the presence of a rubber polymer containing an acrylate monomer unit and a polyfunctional monomer unit, wherein the total amount of the polyfunctional monomer units in the rubber polymer is 0.3 to 3 parts by mass per 100 parts by mass of the acrylate monomer unit, and the total amount of the polyfunctional monomer units contains 30 to 95% by mass of a polyfunctional monomer unit having 2 unsaturated bonds and 5 to 70% by mass of a polyfunctional monomer unit having 3 unsaturated bonds, based on 100% by mass of the total amount of the polyfunctional monomer units.

[2] The acrylic rubber-based graft copolymer according to [1], wherein the rubbery polymer is obtained by mixing a copolymer emulsion obtained by polymerizing a monomer mixture containing an acrylate-based monomer and a polyfunctional monomer with an acid-group-containing copolymer emulsion to increase the weight of the copolymer emulsion, and then further adding a monomer including an acrylate-based monomer to the copolymer emulsion to polymerize the copolymer emulsion.

[3] The acrylic rubber-based graft copolymer according to [1] or [2], wherein the volume average particle diameter of the rubbery polymer is 300 to 600 nm.

[4] A thermoplastic resin composition characterized by containing the acrylic rubber-based graft copolymer described in any one of [1] to [3] (hereinafter referred to as "acrylic rubber-based graft copolymer (A)").

[5] The thermoplastic resin composition according to [4], which comprises an acrylic rubber-based graft copolymer (A) and an acrylic rubber-based graft copolymer (hereinafter referred to as "acrylic rubber-based graft copolymer (B)") obtained by graft-polymerizing a vinyl monomer in the presence of a rubbery polymer containing an acrylate monomer unit having a volume average particle diameter of 70 to 200 nm.

[6] The thermoplastic resin composition according to [5], wherein the total amount of the rubbery polymer contained in the thermoplastic resin composition is 5 to 30 parts by mass, and the total amount of the rubbery polymer contained in the thermoplastic resin composition is 100% by mass, the rubbery polymer contained in the acrylic rubber graft copolymer (A) is 20 to 70% by mass, and the rubbery polymer contained in the acrylic rubber graft copolymer (B) is 30 to 80% by mass, based on 100 parts by mass of the resin component in the thermoplastic resin composition.

[7] The thermoplastic resin composition according to [5] or [6], which comprises 0 to 90 parts by mass of the thermoplastic resin (C) other than the acrylic rubber-based graft copolymer (A) and the acrylic rubber-based graft copolymer (B).

[8] The thermoplastic resin composition according to any one of [5] to [7], wherein the acrylic rubber-based graft copolymer (B) is obtained by polymerizing 100 mass% of an acrylate-based monomer at a polymerization rate of 3 mass%/min or more.

[9] A molded article of a thermoplastic resin composition, which is obtained by molding the thermoplastic resin composition according to any one of [4] to [8 ].

Effects of the invention

The acrylic rubber-based graft copolymer and the thermoplastic resin composition of the present invention are excellent in impact resistance, rigidity, appearance and a balance of these characteristics, and also excellent in weather resistance, and therefore, can be used for automobile material applications, building material applications and household electrical appliance applications, which have been in increasing demand in recent years, and have extremely high industrial utility values.

Detailed Description

The following describes embodiments of the present invention in detail.

In the present specification, "unit" refers to a structural moiety derived from a monomer compound (monomer) before polymerization, and for example, "acrylate monomer unit" refers to a structural moiety derived from an acrylate monomer.

In the present specification, "(meth) acrylic acid" means either or both of "acrylic acid" and "methacrylic acid".

[ acrylic rubber-based graft copolymer (A) ]

The acrylic rubber graft copolymer (A)) of the present invention is a graft copolymer obtained by graft-polymerizing a vinyl monomer in the presence of a rubber polymer containing an acrylate monomer unit and a polyfunctional monomer unit, wherein the total amount of the polyfunctional monomer units in the rubber polymer is 0.3 to 3 parts by mass per 100 parts by mass of the acrylate monomer unit, and the total amount of the polyfunctional monomer units contains 30 to 95% by mass of a polyfunctional monomer unit having 2 unsaturated bonds and 5 to 70% by mass of a polyfunctional monomer unit having 3 unsaturated bonds per 100% by mass.

The rubber polymer (hereinafter, sometimes referred to as "rubber polymer (a)") used in the acrylic rubber graft copolymer (a) of the present invention contains an acrylate monomer unit and a polyfunctional monomer unit as essential components.

The acrylate monomer is preferably an alkyl acrylate having an alkyl group with 1 to 12 carbon atoms. As such an alkyl acrylate, an ester of acrylic acid and an alcohol having a linear or side chain of 1 to 12 carbon atoms is used. For example, methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, isobutyl acrylate, tert-butyl acrylate, 2-ethylhexyl acrylate, and the like can be used, and an ester having an alkyl group with 1 to 8 carbon atoms is particularly preferable. These esters may be used alone or in combination of 2 or more.

The content of the acrylate monomer unit in 100% by mass of the rubber polymer (a) is preferably 75% by mass or more, more preferably 85% by mass or more, and particularly preferably 95% by mass or more. When the content of the acrylate monomer unit is less than the lower limit, the obtained acrylic rubber graft copolymer (a) and the thermoplastic resin composition may have some properties of weather resistance, impact resistance, rigidity and appearance deteriorated.

The total content of the polyfunctional monomer units in the rubber polymer (a) is 0.3 to 3 parts by mass, preferably 2 parts by mass or less, and particularly preferably 1.5 parts by mass or less, and on the other hand, is preferably 0.4 parts by mass or more, and particularly preferably 0.5 parts by mass or more, per 100 parts by mass of the acrylate monomer units. When the content of the polyfunctional monomer unit exceeds the above upper limit, the impact resistance of the resulting acrylic rubber-based graft copolymer (A) and thermoplastic resin composition may be lowered, and when the content is less than the above lower limit, the appearance may be lowered.

The polyfunctional monomer unit contains only a polyfunctional monomer unit having 2 unsaturated bonds and a polyfunctional monomer unit having 3 unsaturated bonds, and the ratio of the polyfunctional monomer unit having 2 unsaturated bonds is 30 to 95% by mass, the ratio of the polyfunctional monomer unit having 3 unsaturated bonds is 5 to 70% by mass, the ratio of the polyfunctional monomer unit having 2 unsaturated bonds is more preferably 35% by mass or more, the ratio of the polyfunctional monomer unit having 3 unsaturated bonds is more preferably 65% by mass or less, the ratio of the polyfunctional monomer unit having 2 unsaturated bonds is more preferably 40% by mass or more, and the ratio of the polyfunctional monomer unit having 3 unsaturated bonds is more preferably 60% by mass or less, with respect to 100% by mass of the total amount of the polyfunctional monomer units in the rubber polymer (a). Further, it is preferable that the polyfunctional monomer unit having 2 unsaturated bonds is 90% by mass or less and the polyfunctional monomer unit having 3 unsaturated bonds is 10% by mass or more, and it is particularly preferable that the polyfunctional monomer unit having 2 unsaturated bonds is 80% by mass or less and the polyfunctional monomer unit having 3 unsaturated bonds is 20% by mass or more.

When the ratio of the polyfunctional monomer unit having 2 unsaturated bonds is less than the lower limit and the polyfunctional monomer having 3 unsaturated bonds exceeds the upper limit, the appearance of the resulting acrylic rubber-based graft copolymer (a) and thermoplastic resin composition may be deteriorated. On the other hand, when the polyfunctional monomer unit having 2 unsaturated bonds exceeds the upper limit and the polyfunctional monomer unit having 3 unsaturated bonds is less than the lower limit, the impact strength and rigidity of the resulting acrylic rubber graft copolymer (a) and thermoplastic resin composition may be lowered.

Examples of the polyfunctional monomer having 2 unsaturated bonds of the present invention include di (meth) acrylates of diols such as allyl methacrylate, ethylene glycol dimethacrylate, 1, 3-butanediol dimethacrylate and 1, 6-hexanediol diacrylate, 2-propenyl acrylate, divinylbenzene, etc., among which allyl methacrylate having an allyl group and 2-propenyl acrylate are preferable, and allyl methacrylate is particularly preferable from the viewpoint of improving the efficiency of the physical properties of the resulting resin composition.

Examples of the polyfunctional monomer having 3 or more unsaturated bonds include triallyl isocyanurate, triallyl cyanurate, triallyl trimellitate, and the like having an aromatic ring, among which triallyl isocyanurate and triallyl cyanurate having a triazine ring are preferable, and triallyl isocyanurate is particularly preferable from the viewpoint of polymerization stability.

These polyfunctional monomers having 2 unsaturated bonds and polyfunctional monomers having 3 unsaturated bonds may be used alone or in combination of 2 or more.

In addition, in the rubber polymer (a), other monomers copolymerizable with the acrylate monomer may be used as needed, in addition to the acrylate monomer and the polyfunctional monomer.

Examples of the other monomer copolymerizable with the acrylate monomer include aromatic vinyl monomers such as styrene, α -methylstyrene and p-methylstyrene, unsaturated nitrile monomers such as acrylonitrile and methacrylonitrile, and methacrylate monomers such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, t-butyl methacrylate and 2-ethylhexyl methacrylate. These monomers may be used alone or in combination of 2 or more.

Further, the rubber polymer (a) may be a composite rubber of a rubber polymer containing an acrylate monomer unit and a polyfunctional monomer unit and a rubber polymer composed of a monomer unit other than the acrylate monomer unit. In this case, examples of the rubbery polymer composed of a monomer unit other than the acrylate monomer unit include ethylene-propylene rubber (EPR), ethylene-propylene-diene rubber (EPDM), diene rubber, and polyorganosiloxane. As a method for obtaining the composite rubber, for example, a method of polymerizing an acrylate monomer and a polyfunctional monomer in the presence of a rubbery polymer composed of a monomer unit other than an acrylate monomer unit; a known method such as a method of enlarging a rubbery polymer composed of a monomer other than an acrylate monomer and a rubbery polymer containing an acrylate monomer and a polyfunctional monomer.

The rubber polymer (a) of the present invention is preferably produced by emulsion polymerization of the monomer mixture.

As the emulsifier used in the emulsion polymerization, an anionic emulsifier is preferable in terms of excellent emulsion stability during the emulsion polymerization and improvement of the polymerization rate.

Examples of the anionic emulsifier include carboxylates (e.g., sodium sarcosinate, potassium fatty acid, sodium fatty acid, dipotassium alkenylsuccinate, rosin acid soap, etc.), alkyl sulfate ester salts, sodium alkylbenzenesulfonate, sodium alkyl sulfosuccinate, sodium polyoxyethylene nonylphenyl ether sulfate, etc., and sodium sarcosinate, dipotassium alkenylsuccinate, alkyl sulfate ester salts, sodium alkylbenzenesulfonate, sodium alkyl sulfosuccinate, sodium polyoxyethylene nonylphenyl ether sulfate, etc. are preferable from the viewpoint of suppressing hydrolysis of the above polyfunctional monomer, and among these, dipotassium alkenylsuccinate is particularly preferable from the viewpoint of polymerization stability, etc.

These emulsifiers may be used alone in 1 kind, or may be used in combination of 2 or more kinds.

The rubbery polymer (a) used in the acrylic rubber-based graft copolymer (a) of the present invention is preferably produced by mixing a copolymer emulsion obtained by polymerizing a monomer mixture containing an acrylate-based monomer and a polyfunctional monomer with an acid-group-containing copolymer emulsion to increase the weight of the copolymer emulsion, and more preferably by adding a condensed acid salt before mixing the acid-group-containing copolymer emulsion. By thus enlarging the particle size, the rubbery polymer (a) having a desired volume average particle diameter can be obtained, and by adding the condensed acid salt, the generation of the rubbery polymer having a particle diameter of 200nm or less can be suppressed.

When the rubbery polymer (a) is thickened, as the condensed acid salt to be added before the acid group-containing copolymer emulsion is mixed, a salt of a polybasic acid such as phosphoric acid or silicic acid with an alkali metal and/or an alkaline earth metal can be used, a salt of pyrophosphoric acid (pyrophosphoric acid is a condensed acid of phosphoric acid) with an alkali metal is preferable, and sodium pyrophosphate or potassium pyrophosphate is particularly preferable. The amount of the condensed acid salt added is preferably 0.1 to 10 parts by mass, more preferably 0.5 to 7 parts by mass, per 100 parts by mass (in terms of solid content) of a copolymer emulsion obtained by polymerizing a monomer mixture containing an acrylate monomer and a polyfunctional monomer. When the amount of the condensed acid salt added is less than the lower limit, the enlargement does not proceed sufficiently. When the amount exceeds the upper limit, the enlargement may not be sufficiently performed, or the rubber emulsion may become unstable and a large amount of coagulum may be generated.

The acid group-containing copolymer emulsion used for the enlargement is an emulsion of an acid group-containing copolymer obtained by polymerizing a monomer mixture containing an acid group-containing monomer, an alkyl (meth) acrylate monomer, and optionally, another monomer copolymerizable with these monomers in water.

The acid group-containing monomer is preferably an unsaturated compound having a carboxyl group, and examples of the compound include (meth) acrylic acid, itaconic acid, crotonic acid, and the like, and (meth) acrylic acid is particularly preferable. The acid group-containing monomer may be used alone or in combination of two or more.

Examples of the alkyl ester monomer of (meth) acrylic acid include esters of acrylic acid and/or methacrylic acid with alcohols having a linear or branched alkyl group having 1 to 12 carbon atoms, examples of which include methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, isobutyl acrylate, t-butyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, and 2-ethylhexyl methacrylate, and alkyl esters of (meth) acrylic acid having an alkyl group having 1 to 8 carbon atoms are particularly preferable. The alkyl ester (meth) acrylate monomer may be used alone or in combination of two or more.

The other monomers are monomers copolymerizable with the acid group-containing monomer and the alkyl ester of (meth) acrylic acid monomer, and are monomers other than the acid group-containing monomer and the alkyl ester of (meth) acrylic acid monomer. Examples of the other monomer include aromatic vinyl monomers (e.g., styrene, α -methylstyrene, p-methylstyrene, etc.), unsaturated nitrile monomers (e.g., acrylonitrile, methacrylonitrile, etc.), compounds having 2 or more polymerizable functional groups (e.g., allyl methacrylate, polyethylene glycol dimethacrylate, triallyl cyanurate, triallyl isocyanurate, triallyl trimellitate, etc.), and the like. One of the other monomers may be used alone, or two or more of them may be used in combination.

The amount of the polymerizable monomer is preferably 5 to 40% by mass, more preferably 8 to 30% by mass, of the acid group-containing monomer unit, preferably 60 to 95% by mass, more preferably 70 to 92% by mass, of the alkyl (meth) acrylate monomer unit, and preferably 0 to 48% by mass, more preferably 0 to 30% by mass, of the other copolymerizable monomer unit, based on 100% by mass of the acid group-containing copolymer emulsion. When the ratio of the acid group-containing monomer unit is less than the lower limit, the thickening ability is almost lost. When the ratio of the acid group-containing monomer unit exceeds the upper limit, a large amount of coagulum is generated in the production of the acid group-containing copolymer emulsion.

The acid group-containing copolymer emulsion can be usually produced by an emulsion polymerization method.

As the emulsifier used in the emulsion polymerization, known emulsifiers such as carboxylic acid-based emulsifiers exemplified by oleic acid, palmitic acid, stearic acid, alkali metal salts of rosin acid, alkali metal salts of alkenylsuccinic acid, and the like, and anionic emulsifiers selected from alkyl sulfate esters, sodium alkylbenzenesulfonate, sodium alkyl sulfosuccinate, sodium polyoxyethylene nonylphenyl ether sulfate, and the like can be used alone or in combination of 2 or more.

The emulsifier may be used in such a manner that the whole amount is added at once in the initial stage of polymerization, or a part of the emulsifier is used in the initial stage of polymerization and the remaining part is added intermittently or continuously during polymerization. The amount and the method of use of the emulsifier affect the particle size of the acid group-containing copolymer emulsion, and even the particle size of the rubber polymer (a) emulsion, which is enlarged in particle size, and therefore it is necessary to select an appropriate amount and method of use.

As the polymerization initiator used in the polymerization, a thermal decomposition type initiator, a redox type initiator, or the like can be used. Examples of the thermal decomposition type initiator include potassium persulfate, sodium persulfate, and ammonium persulfate, and examples of the redox type initiator include a combination of an organic peroxide represented by cumene hydroperoxide, sodium formaldehyde sulfoxylate, and an iron salt. These can be used alone or in combination of 2 or more.

In addition to these polymerization initiators, a chain transfer agent such as a mercaptan such as t-dodecyl mercaptan or n-octyl mercaptan for adjusting the molecular weight, terpinolene, or an α -methylstyrene dimer, or an electrolyte such as an alkali or an acid for adjusting the pH, or a viscosity reducing agent may be added.

The amount of the acid group-containing copolymer emulsion added is preferably 0.1 to 10 parts by mass (in terms of solid content), more preferably 0.3 to 7 parts by mass, per 100 parts by mass (in terms of solid content) of a copolymer emulsion obtained by polymerizing a monomer mixture containing an acrylate monomer and a polyfunctional monomer. When the amount of the acid-group-containing copolymer emulsion added is less than the lower limit, the enlargement does not proceed sufficiently, and a large amount of coagulum is also generated. When the amount of the acid-group-containing copolymer emulsion exceeds the upper limit, the pH of the enlarged emulsion decreases and the emulsion tends to be unstable.

In the stage of adding the condensed acid salt to the copolymer emulsion obtained by polymerizing the monomer mixture containing the acrylate monomer and the polyfunctional monomer before adding the acid group-containing copolymer emulsion, the pH of the mixed solution is preferably 7 or more. When the pH is less than 7, the hypertrophy does not sufficiently progress. In order to adjust the pH to 7 or more, a general basic compound such as sodium hydroxide or potassium hydroxide can be used.

Addition of the condensed acid salt is preferably a method of adding the condensed acid salt at one time before mixing the acid group-containing copolymer emulsion.

The acid-group-containing copolymer emulsion is preferably added in one portion or intermittently by dropping.

Stirring during the fertilization needs to be properly controlled. When the stirring is insufficient, the emulsion is locally thickened to leave a non-thickened rubbery polymer, and when the stirring is excessive, the thickened emulsion becomes unstable to generate a large amount of coagulum. The temperature for the enlargement is preferably 20 to 90 ℃, more preferably 30 to 80 ℃. If the temperature is outside this range, the enlargement may not be sufficiently performed.

The rubbery polymer (a) used in the acrylic rubber graft copolymer (a) of the present invention is preferably enlarged with the acid group-containing copolymer emulsion as described above, and then polymerized with a monomer including an acrylate monomer. By performing this operation, the appearance of the obtained acrylic rubber-based graft copolymer (a) and the thermoplastic resin composition can be further improved.

The amount of the monomer including the acrylate monomer to be added is preferably 50% by mass or less, more preferably 40% by mass or less, particularly preferably 30% by mass or less, and is preferably 5% by mass or more, more preferably 10% by mass or more, particularly preferably 15% by mass or more, based on 100% by mass of the total amount of the monomer including the acrylate monomer used in the production of the rubber polymer (a). When the amount of the monomer including the acrylate monomer added exceeds the upper limit, a rubbery polymer having a particle diameter of 200nm or less is produced, and the impact resistance and appearance of the resulting acrylic rubber graft copolymer (A) and thermoplastic resin composition may be deteriorated. When the amount of the monomer including the acrylate monomer added is less than the lower limit, the appearance improving effect is insufficient.

The method of adding the monomer including the acrylate monomer may be any method such as addition at once, addition in portions, or continuous addition, and the continuous addition is more preferable in terms of suppressing the decrease in impact resistance and the decrease in appearance due to the formation of the rubbery polymer having a particle diameter of 200nm or less.

The polyfunctional monomer containing an acrylate monomer is an acrylate monomer, a polyfunctional monomer, and other monomers copolymerizable with those monomers, and may be only an acrylate monomer, may include an acrylate monomer and a polyfunctional monomer, and may include an acrylate monomer, a polyfunctional monomer, and other monomers, as long as the monomer contains at least an acrylate monomer. Particularly preferably, the acrylic acid ester-based monomer and the polyfunctional monomer are included.

In the case of adding such a monomer including an acrylate monomer, the ratio of the polyfunctional monomer to other monomers used as needed may be changed for the following monomers: a polyfunctional monomer and other monomers used as needed in a stage of polymerizing a monomer including an acrylate monomer before enlargement, and a polyfunctional monomer and other monomers used as needed in a stage of polymerizing an additional monomer including an acrylate monomer after enlargement. However, the total amount of the polyfunctional monomer and other monomers used as needed at the stage of terminating the polymerization as a rubber polymer is required to be within the above range. By reducing the amount of the polyfunctional monomer used in the polymerization step of the monomer including the acrylate monomer before the enlargement and increasing the amount of the polyfunctional monomer used in the polymerization step of the additional monomer including the acrylate monomer after the enlargement, the impact resistance, rigidity and appearance balance of the resulting acrylic rubber graft copolymer (a) and the thermoplastic resin composition can be improved. In this case, for example, when the acrylate monomer used before the enlargement is X mass% based on 100 mass% of the total amount of the acrylate monomer used, the polyfunctional monomer used before the enlargement may be X mass% or less, for example, 0.3X to X mass%, and the polyfunctional monomer used at the stage of polymerizing the additional monomer including the acrylate monomer after the enlargement may be (100-X) mass% or more, for example, (100-X) to 2X (100-X) mass%, based on 100 mass% of the total amount of the polyfunctional monomer used.

The volume average particle diameter of the rubbery polymer (a) used in the acrylic rubber-based graft copolymer (a) of the present invention is preferably 300nm or more, more preferably 350nm or more. When the volume average particle diameter is less than the lower limit, the impact resistance of the resulting acrylic rubber-based graft copolymer (A) and thermoplastic resin composition may be lowered. The volume average particle diameter of the rubber polymer (a) is preferably 600nm or less, more preferably 550nm or less. When the volume average particle diameter exceeds the above upper limit, the appearance of the resulting acrylic rubber-based graft copolymer (A) and thermoplastic resin composition may be deteriorated.

Further, the content of the rubber polymer having a particle diameter of 200nm or less is preferably 20% by mass or less, more preferably 10% by mass or less, relative to 100% by mass of the rubber polymer (a). When the content of the rubbery polymer having a particle diameter of 200nm or less exceeds the above upper limit, the impact resistance of the resulting acrylic rubber-based graft copolymer (A) and the thermoplastic resin composition may be lowered.

The acrylic rubber-based graft copolymer (a) of the present invention is obtained by graft-polymerizing a vinyl monomer in the presence of the rubber polymer (a).

The vinyl monomer used for the graft polymerization preferably includes an unsaturated nitrile monomer and an aromatic vinyl monomer and other monomers used as necessary.

Examples of the unsaturated nitrile monomer include acrylonitrile and methacrylonitrile. These may be used alone or in combination of 2 or more.

Examples of the aromatic vinyl monomer include styrene, α -methylstyrene, and vinyltoluene. These may be used alone or in combination of 2 or more.

The other monomer is a monomer copolymerizable with the unsaturated nitrile-based monomer and the aromatic vinyl-based monomer, and is a monomer other than the unsaturated nitrile-based monomer and the aromatic vinyl-based monomer. Examples of the other monomer include methyl methacrylate, ethyl methacrylate, N-butyl methacrylate, 2-ethylhexyl acrylate, methyl acrylate, ethyl acrylate, N-butyl acrylate, 2-hydroxyethyl methacrylate, glycidyl methacrylate, N-dimethylaminoethyl methacrylate, acrylamide, methacrylamide, maleic anhydride, and N-substituted maleimide. As for the other monomers, one kind may be used alone or two or more kinds may be used in combination.

The vinyl monomer graft-polymerized with the rubber polymer (a) is preferably a monomer mixture of an aromatic vinyl monomer such as styrene and an unsaturated nitrile monomer such as acrylonitrile, and particularly preferably a mixture of styrene and acrylonitrile, from the viewpoint of excellent impact resistance of the resulting molded article.

The proportion of the unsaturated nitrile monomer in the monomer mixture to be graft-polymerized with the rubber polymer (a) is preferably 3 to 50% by mass, more preferably 10 to 40% by mass, of the unsaturated nitrile monomer in the monomer mixture (100% by mass). When the proportion of the unsaturated nitrile monomer is not less than the lower limit, the impact resistance of the resulting molded article is good. When the proportion of the unsaturated nitrile monomer is not more than the upper limit, discoloration of the resulting molded article due to heat is suppressed.

The proportion of the aromatic vinyl monomer in the monomer mixture (100 mass%) is preferably 20 to 97 mass%, more preferably 30 to 80 mass%. When the ratio of the aromatic vinyl monomer is not less than the lower limit, the obtained moldability is good. When the proportion of the aromatic vinyl monomer is not more than the upper limit, the impact resistance of the resulting molded article is good.

The proportion of the other monomer in the monomer mixture (100 mass%) is preferably 50 mass% or less, more preferably 40 mass% or less. When the ratio of the other monomer is not more than the upper limit, the balance between the impact resistance and the appearance is good.

The acrylic rubber-based graft copolymer (a) of the present invention is preferably produced by emulsion polymerization of the above monomer mixture in the presence of an emulsion of the rubbery polymer (a).

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

Examples of the polymerization initiator used in the emulsion polymerization include peroxides, azo initiators, and redox initiators comprising a combination of an oxidizing agent and a reducing agent.

In the emulsion polymerization, a chain transfer agent for controlling the graft ratio and the molecular weight of the graft component may be used.

As a method of adding monomers such as aromatic vinyl monomers and unsaturated nitrile monomers in the emulsion polymerization, a method of adding the whole amount at once, adding in portions, continuously adding, or the like may be used, or a combination of the above methods of adding a part at once, continuously adding the rest, or the like may be used. Alternatively, a method may be used in which the monomer is added and then the mixture is left for a while, and then a polymerization initiator is added to initiate polymerization.

The following method can be mentioned as a method for recovering the acrylic rubber-based graft copolymer (a) from the emulsion of the acrylic rubber-based graft copolymer (a) obtained by emulsion polymerization.

The graft copolymer emulsion is put into hot water in which a coagulant is dissolved to solidify the graft copolymer. Next, the cured graft copolymer is redispersed in water or warm water to prepare a slurry, and the emulsifier residue remaining in the graft copolymer is dissolved out in water and washed. Next, the slurry is dewatered by a dehydrator or the like, and the obtained solid is dried by an air dryer or the like, whereby the graft copolymer is recovered in the form of powder or particles.

The above-mentioned recovery operation may be carried out by mixing in advance the acrylic rubber-based graft copolymer (A) emulsion, the acrylic rubber-based graft copolymer (B) emulsion described later, and optionally, another polymer emulsion.

Examples of the coagulant include inorganic acids (sulfuric acid, hydrochloric acid, phosphoric acid, nitric acid, and the like), metal salts (calcium chloride, calcium acetate, aluminum sulfate, and the like), and the like. The coagulant is appropriately selected depending on the kind of the emulsifier. For example, when only a carboxylate (fatty acid salt, rosin acid soap, or the like) is used as the emulsifier, any coagulant may be used. When an emulsifier which exhibits stable emulsifying power even in an acidic region, such as sodium alkylbenzenesulfonate, is used as the emulsifier, the use of an inorganic acid is insufficient, and it is necessary to use a metal salt.

The content of the rubbery polymer (a) in the acrylic rubber-based graft copolymer (a) is preferably 10 to 90 parts by mass, more preferably 20 to 80 parts by mass, and particularly preferably 30 to 70 parts by mass, based on 100 parts by mass of the acrylic rubber-based graft copolymer (a). When the content of the rubber polymer (a) is not less than the lower limit, the impact resistance of the obtained acrylic rubber-based graft copolymer (a) and the thermoplastic resin composition is further improved, and when the content of the rubber polymer (a) is not more than the upper limit, the obtained acrylic rubber-based graft copolymer (a) and the thermoplastic resin composition can maintain good appearance.

The graft ratio of the acrylic rubber-based graft copolymer (A) is preferably 30 to 90%, particularly preferably 50 to 80%. When the graft ratio of the acrylic rubber-based graft copolymer (A) is within the above range, good appearance can be maintained. The graft ratio of the acrylic rubber-based graft copolymer (a) can be determined by the method described in the following example.

Further, the acetone-soluble material of the acrylic rubber-based graft copolymer (A) preferably has a reduced viscosity of 0.40 to 1.00g/dL, particularly preferably 0.50 to 0.80 g/dL. When the reduced viscosity of the acetone-soluble material of the acrylic rubber-based graft copolymer (a) is not less than the lower limit, the impact strength is further improved, and when the reduced viscosity is not more than the upper limit, good appearance and moldability can be maintained. The reduced viscosity of the acetone-soluble material of the acrylic rubber-based graft copolymer (a) can be determined by the method described in the section of examples described later.

[ thermoplastic resin composition ]

The thermoplastic resin composition of the present invention is characterized by containing the acrylic rubber-based graft copolymer (a) of the present invention, preferably containing the acrylic rubber-based graft copolymer (a) of the present invention and an acrylic rubber-based graft copolymer (B) having a volume average particle diameter of 70 to 200nm (hereinafter sometimes referred to as "the acrylic rubber-based graft copolymer (B)" of the present invention), the acrylic rubber-based graft copolymer (B) being obtained by polymerizing a vinyl monomer in the presence of a rubbery polymer containing an acrylate monomer unit (hereinafter sometimes referred to as "the rubbery polymer (B)").

The rubbery polymer (B) used in the acrylic rubber graft copolymer (B) of the present invention contains an acrylate monomer unit as an essential component.

The acrylate monomer is preferably an alkyl acrylate having an alkyl group with 1 to 12 carbon atoms. As such an alkyl acrylate, an ester of acrylic acid and an alcohol having a linear or side chain of 1 to 12 carbon atoms can be used. For example, methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, isobutyl acrylate, tert-butyl acrylate, 2-ethylhexyl acrylate, etc. can be used, and it is particularly preferable that the number of carbon atoms in the alkyl group is 1 to 8. These may be used alone or in combination of 2 or more.

The rubber polymer (b) may contain a polyfunctional monomer unit in addition to the acrylate monomer unit, and in this case, the polyfunctional monomer used in the rubber polymer (b) is not particularly limited, and a known polyfunctional monomer may be used. Examples of the known polyfunctional monomer include di (meth) acrylates of diols such as ethylene glycol dimethacrylate, 1, 3-butanediol dimethacrylate and 1, 6-hexanediol diacrylate, triallyl cyanurate, triallyl isocyanurate, triallyl trimellitate and allyl methacrylate. These may be used alone or in combination of 2 or more.

In addition, as the rubber polymer (b), another monomer copolymerizable with the acrylate monomer is used as necessary. Examples of the other monomer copolymerizable with the acrylate monomer include aromatic vinyl monomers such as styrene, α -methylstyrene and p-methylstyrene, unsaturated nitrile monomers such as acrylonitrile and methacrylonitrile, and methacrylate monomers such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, t-butyl methacrylate and 2-ethylhexyl methacrylate. These may be used alone or in combination of 2 or more.

Further, the rubber polymer (B) used in the acrylic rubber-based graft copolymer (B) of the present invention may be a composite rubber comprising a rubber polymer containing an acrylate monomer unit and a rubber polymer composed of a monomer unit other than the acrylate monomer unit. Examples of the rubbery polymer composed of a monomer unit other than the acrylate monomer unit include ethylene-propylene rubber (EPR), ethylene-propylene-diene rubber (EPDM), diene rubber, and polyorganosiloxane. As a method for obtaining the composite rubber, for example, a known method such as a method of polymerizing an acrylate monomer in the presence of a rubbery polymer composed of a monomer unit other than an acrylate monomer unit can be used.

The content of the acrylate monomer unit is preferably 75% by mass or more, more preferably 85% by mass or more, and particularly preferably 95% by mass or more, based on 100% by mass of the rubber polymer (b). When the content of the acrylate monomer unit is less than the above lower limit, the obtained thermoplastic resin composition may have some properties of weather resistance, impact resistance, rigidity and appearance reduced.

The content of the polyfunctional monomer unit in the rubber polymer (b) is preferably 3 parts by mass or less, more preferably 2 parts by mass or less, and particularly preferably 1 part by mass or less, and on the other hand, is preferably 0.05 parts by mass or more, more preferably 0.1 parts by mass or more, and particularly preferably 0.15 parts by mass or more, per 100 parts by mass of the acrylate monomer unit. When the content of the polyfunctional monomer unit in the rubber polymer (b) exceeds the above upper limit, the impact resistance of the resulting thermoplastic resin composition may be lowered, and when it is less than the above lower limit, the appearance may be lowered.

When the rubber polymer (b) contains another monomer unit copolymerizable with the acrylate monomer, the content thereof is preferably 25% by mass or less, more preferably 15% by mass or less, and particularly preferably 5% by mass or less in terms of the proportion in the rubber polymer (b). When the content of the other monomer unit exceeds the above upper limit, any of weather resistance, impact resistance, rigidity and appearance of the resulting thermoplastic resin composition may be lowered.

The rubber polymer emulsion (B) of the acrylic rubber-based graft copolymer (B) is preferably produced by emulsion polymerization. In particular, it is preferably produced by a batch emulsion polymerization method in which an acrylate monomer is added at once, and in the production, the polymerization rate is 3 mass%/min or more, and particularly preferably 3.5 mass%/min or more, based on 100 mass% of all acrylate monomers used for producing the rubber polymer (b). When the polymerization rate is less than the lower limit, the appearance of the resulting thermoplastic resin composition may be deteriorated. The upper limit of the polymerization rate is not particularly limited, and in the case of industrial production, the polymerization rate is usually 20 mass%/minute or less, more preferably 10 mass%/minute or less because the higher the polymerization rate is, the more difficult it is to remove the generated heat of polymerization.

The reason why the appearance can be improved by the polymerization rate is that the detailed structure of the rubber polymer (b) cannot be analyzed, and thus the detailed reason is not clear, and it is considered that the crosslinked structure of the rubber polymer (b) is changed.

As the polymerization initiator used in the emulsion polymerization, a redox initiator in which an oxidizing agent and a reducing agent are combined is preferable. In the case of a thermally decomposable initiator such as a peroxide or an azo initiator, it is industrially disadvantageous to use a large amount of the initiator for adjusting the polymerization rate or to carry out the polymerization at a high temperature. When a redox initiator is used, the polymerization rate can be adjusted by the amounts of the metal ion as a catalyst, the oxidizing agent and the reducing agent.

The volume average particle diameter of the rubber polymer (B) used in the acrylic rubber-based graft copolymer (B) is preferably 70nm or more, more preferably 80nm or more, and on the other hand, preferably 200nm or less, more preferably 170nm or less, and particularly preferably 150nm or less. When the volume average particle diameter of the rubber polymer (b) is less than the lower limit, the mechanical strength of the resulting thermoplastic resin composition may be lowered. On the other hand, when the volume average particle diameter exceeds the upper limit, the appearance may be deteriorated.

The acrylic rubber-based graft copolymer (B) is obtained by graft-polymerizing a vinyl monomer in the presence of the rubber polymer (B).

The vinyl monomer may be the same as that used for the acrylic rubber graft copolymer (a), and the kind and the use ratio of the suitable vinyl monomer are the same.

The acrylic rubber-based graft copolymer (B) can be produced by a known production method such as an emulsion polymerization method or a continuous polymerization method. Among these methods, the emulsion polymerization method is particularly preferable. As the emulsifier, initiator, chain transfer agent and the like used in the emulsion polymerization method, known ones similar to those used in the production of the acrylic rubber-based graft copolymer (a) can be used.

The recovery of the acrylic rubber-based graft copolymer (B) from the emulsion of the acrylic rubber-based graft copolymer (B) obtained by emulsion polymerization can be carried out in the same manner as the above-mentioned recovery method of the acrylic rubber-based graft copolymer (a).

As described above, the acrylic rubber-based graft copolymer (A) emulsion, the acrylic rubber-based graft copolymer (B) emulsion, and optionally other polymer emulsion may be mixed in advance and then subjected to the above-mentioned recovery operation.

In the acrylic rubber-based graft copolymer (B), the content of the rubbery polymer (B) is preferably 10 to 90 parts by mass, more preferably 20 to 80 parts by mass, and particularly preferably 30 to 70 parts by mass, based on 100 parts by mass of the acrylic rubber-based graft copolymer (B). When the content of the rubber polymer (b) is not less than the lower limit, the impact resistance of the resulting thermoplastic resin composition is further improved, and when the content of the rubber polymer is not more than the upper limit, the resulting thermoplastic resin composition can maintain good appearance.

The graft ratio of the acrylic rubber-based graft copolymer (B) is preferably 30 to 90%, particularly preferably 35 to 70%. When the graft ratio of the acrylic rubber-based graft copolymer (B) is within the above range, good appearance can be maintained. The graft ratio of the acrylic rubber-based graft copolymer (B) can be determined by the method described in the section of examples described later.

Further, the acetone-soluble material of the acrylic rubber-based graft copolymer (B) preferably has a reduced viscosity of 0.40 to 1.00g/dL, particularly preferably 0.50 to 0.80 g/dL. When the reduced viscosity of the acetone-soluble material of the acrylic rubber-based graft copolymer (B) is not less than the lower limit, the impact strength is further improved, and when the reduced viscosity is not more than the upper limit, good appearance and moldability can be maintained. The reduced viscosity of the acetone-soluble material of the acrylic rubber-based graft copolymer (B) can be determined by the method described in the section of examples described later.

[ thermoplastic resin (C) ]

The thermoplastic resin composition of the present invention may contain another thermoplastic resin (C) other than the acrylic rubber-based graft copolymer (a) and the acrylic rubber-based graft copolymer (B). In this case, the thermoplastic resin (C) includes styrene-based resins, methyl methacrylate-styrene copolymers (MS resins), (meth) acrylic resins, polymethyl methacrylate, Polycarbonates (PC), polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polyvinyl chloride, polyethylene, polyolefins such as polypropylene, styrene-butadiene-styrene (SBS), styrene-butadiene (SBR), hydrogenated SBS, styrene-isoprene-styrene (SIS), styrene-based elastomers such as various olefin-based elastomers, various polyester-based elastomers, polyacetal, modified polyphenylene ether (modified PPE resin), ethylene-vinyl acetate copolymers, polyphenylene sulfide (PPS), polyether sulfone (PES), polyether ether ketone (PEEK), and the like, Polyarylate, liquid crystal polyester resin, polyamide (nylon), and the like. These thermoplastic resins may be used alone in 1 kind, or two or more kinds may be used in combination.

Among these, polybutylene terephthalate (PBT) is preferable from the viewpoint of improving chemical resistance, polyethylene terephthalate (PET) and styrene-based resins are preferable from the viewpoint of improving molding processability, and modified polyphenylene ether (modified PPE) and polyamide are preferable from the viewpoint of improving heat resistance. Further, a styrene-based resin is particularly preferable in terms of a balance between impact resistance and moldability, a (meth) acrylic resin is particularly preferable in terms of improvement of weather resistance, and a polycarbonate resin is particularly preferable in terms of a balance between impact resistance and heat resistance.

The styrene resin is obtained by copolymerizing an unsaturated nitrile monomer such as vinyl cyanide, an unsaturated carboxylic acid anhydride, and another monomer such as N-substituted maleimide, if necessary, with an aromatic vinyl monomer unit as an essential component. These monomer units may be used alone or in combination of two or more.

The styrene-based resin is particularly preferably an acrylonitrile-styrene copolymer, an acrylonitrile- α -methylstyrene copolymer, an acrylonitrile-styrene-N-phenylmaleimide copolymer, an acrylonitrile-styrene- α -methylstyrene-N-phenylmaleimide copolymer, or a styrene-N-phenylmaleimide copolymer.

In the monomer mixture (100 mass%) used in the production of the styrene resin, the proportion of the aromatic vinyl monomer unit contained in the styrene resin is preferably 20 to 100 mass%, more preferably 30 to 90 mass%, and particularly preferably 50 to 80 mass%. When the proportion of the aromatic vinyl monomer is not less than the lower limit, the moldability of the resulting thermoplastic resin composition is good.

In the monomer mixture (100 mass%) used in the production of the styrene resin, the proportion of the unsaturated nitrile monomer unit contained in the styrene resin is preferably 0 to 50 mass%, more preferably 10 to 40 mass%. When the proportion of the unsaturated nitrile monomer is less than the above upper limit, discoloration of the resulting molded article due to heat can be suppressed.

In the monomer mixture (100 mass%) used in the production of the styrene resin, the proportion of the other monomer contained in the styrene resin is preferably 55 mass% or less, and more preferably 40 mass% or less. When the ratio of the other monomer is not more than the upper limit, the impact resistance and the appearance of the resulting molded article are well balanced.

The (meth) acrylic resin is a resin composed of a polymerized component of a methacrylate monomer such as methyl methacrylate; or a resin comprising a methacrylic ester monomer, an acrylic ester monomer such as methyl acrylate, and/or a methacrylic ester monomer, and another monomer copolymerizable with the acrylic ester monomer, wherein the mass ratio of the methacrylic ester monomer and the acrylic ester monomer constituting the (meth) acrylic resin is preferably 100/0 to 50/50, and more preferably 99/1 to 80/20. When the ratio of the acrylate-based monomer is more than this range, the thermal stability and heat resistance of the resulting thermoplastic resin composition tend to be impaired.

It is preferable to use methyl methacrylate as the methacrylate-based monomer and methyl acrylate as the acrylate-based monomer.

Specific examples of the (meth) acrylic resin include "ACRYPET VHS" and "ACRYPET MD" manufactured by Mitsubishi corporation, which is a commercially available product; "ParapetG" manufactured by KURARAY, and the like.

The polycarbonate resin (PC) preferably has a viscosity average molecular weight (Mv) in the range of 10,000 to 45,000, particularly preferably 13,000 to 40,000. When the viscosity average molecular weight of the polycarbonate resin is less than this range, the impact resistance tends to be lowered, and when it exceeds this range, the flowability becomes poor, the moldability becomes poor, and the appearance of the product tends to be poor.

Specific examples of the polycarbonate resin (PC) include, for example, "Ipiplon series" and "NOVAREX series" manufactured by Mitsubishi engineering plastics corporation, which are commercially available; "タフロンシリーズ" manufactured by shinning corporation, and the like.

The other thermoplastic resin (C) can be produced by a known production method such as emulsion polymerization, suspension polymerization, continuous bulk polymerization, or the like.

[ resin component ]

The thermoplastic resin composition of the present invention contains the acrylic rubber-based graft copolymer (a) as a resin component, preferably contains the acrylic rubber-based graft copolymer (B), and further contains another thermoplastic resin (C) as needed.

The total amount of the rubbery polymer contained in the thermoplastic resin composition of the present invention is preferably 5 to 30 parts by mass, and more preferably 7 to 25 parts by mass, per 100 parts by mass of the resin component in the thermoplastic resin composition. When the content of the rubbery polymer in the thermoplastic resin composition is not less than the above lower limit, the impact resistance of the resulting thermoplastic resin composition is further improved, and when the content of the rubbery polymer is not more than the above upper limit, the good appearance and fluidity of the resulting thermoplastic resin composition can be maintained.

In the thermoplastic resin composition of the present invention, the total amount of the rubber polymer contained in the thermoplastic resin composition is 100% by mass, preferably 20 to 70% by mass of the rubber polymer (a) contained in the acrylic rubber graft copolymer (a), 30 to 80% by mass of the rubber polymer (B) contained in the acrylic rubber graft copolymer (B), more preferably 30 to 60% by mass of the rubber polymer (a) contained in the acrylic rubber graft copolymer (a), and 40 to 70% by mass of the rubber polymer (B) contained in the acrylic rubber graft copolymer (B). When the rubber polymer (a) contained in the acrylic rubber-based graft copolymer (a) is not less than the lower limit and the rubber polymer (B) contained in the acrylic rubber-based graft copolymer (B) is not more than the upper limit, the impact resistance of the resulting thermoplastic resin composition is further improved, and when the rubber polymer (a) contained in the acrylic rubber-based graft copolymer (a) is not more than the upper limit and the rubber polymer (B) contained in the acrylic rubber-based graft copolymer (B) is not less than the lower limit, the good appearance of the resulting thermoplastic resin composition can be maintained.

When the acrylic rubber-based graft copolymer of the present invention contains another thermoplastic resin (C), the content thereof is preferably 0 to 70 parts by mass, more preferably 10 to 65 parts by mass, based on 100 parts by mass of the resin component in the thermoplastic resin composition of the present invention. When the amount of the other thermoplastic resin (C) is not more than the upper limit, good appearance can be maintained.

[ other ingredients ]

The thermoplastic resin composition of the present invention may contain, if necessary, colorants such as pigments and dyes, heat stabilizers, light stabilizers, reinforcing agents, fillers, flame retardants, foaming agents, lubricants, plasticizers, antistatic agents, processing aids, and the like.

[ Process for producing thermoplastic resin composition ]

The thermoplastic resin composition of the present invention is produced, for example, by: the acrylic rubber-based graft copolymer (a), the acrylic rubber-based graft copolymer (B), and if necessary, the other thermoplastic resin (C) and other components are mixed in a mixing device such as a V-blender or a henschel mixer, and the mixture obtained by the mixing device is melt-kneaded. In the melt-kneading, a single-screw or twin-screw extruder, a Banbury mixer, a heating kneader, a roll or the like can be used.

[ thermoplastic resin molded article ]

The thermoplastic resin molded article of the present invention obtained by molding the thermoplastic resin composition of the present invention can be used in various applications.

Examples of the method for molding the thermoplastic resin composition of the present invention include injection molding, extrusion molding, blow molding, extrusion molding, calender molding, inflation molding, and the like.

The thermoplastic resin composition of the present invention can also be used as a material for forming a coating layer on a substrate made of other resin, metal, or the like.

In this case, as the constituent material of the substrate to be formed with the coating layer (the coating layer is formed of the thermoplastic resin composition of the present invention), for example, the other thermoplastic resin (C) described above; rubber-modified thermoplastic resins such as ABS resin or high impact polystyrene resin (HIPS); thermosetting resins such as phenol resins and melamine resins.

By coating and molding the thermoplastic resin composition of the present invention on a substrate made of the above-mentioned other resin or metal, weather resistance and good appearance can be imparted.

Such molded articles can be used in various applications. For example, the resin composition can be suitably used for industrial applications, for example, as vehicle parts, in particular, various exterior and interior parts used in a non-coated form, building material parts such as wall materials and window frames, home appliance parts such as tableware, toys, cleaner housings, television housings and air conditioner housings, interior parts, ship parts, communication device housings, notebook computer housings, portable terminal housings, motor device housings such as liquid crystal projector housings, and the like.

Examples

The present invention will be described more specifically with reference to the following examples, but the scope of the present invention is not limited by these examples. In the following examples, "part" is based on mass unless otherwise specified.

In the following, the physical properties of the rubbery polymer and the acrylic rubber-based graft copolymer and the properties of the obtained molded article were measured and evaluated by the following methods.

< solid content >

1g of the emulsion was precisely weighed out as the solid content of the emulsion, the volatile matter was evaporated at 200 ℃ for 20 minutes, and the residue after evaporation was measured to determine the solid content of the emulsion by the following formula.

Solid content (%) = residual substance amount/emulsion mass × 100

< polymerization conversion >

The polymerization conversion was determined by measuring the solid content and using the following equation.

Polymerization conversion (%) =

{ S ÷ 100 × total charged mass-charged mass excluding monomer and water }/total mass of monomer × 100

In the formula, S represents the solid content (%) and the total charged mass represents the total mass of the monomer, water and the like charged into the reactor.

< graft ratio >

The graft ratio of the graft copolymer was calculated by the following method.

To 2.5g of the graft copolymer was added 80mL of acetone, and the mixture was returned in a warm water bath at 65 ℃ for 3 hours to extract acetone-soluble components. The residual acetone-insoluble matter was separated by centrifugation, and the weight after drying was measured to calculate the mass ratio of the acetone-insoluble matter in the graft copolymer. The graft ratio was calculated from the mass ratio of acetone-insoluble matter in the obtained graft copolymer using the following formula.

[ number 1]

< reduced viscosity >

The reduced viscosity was measured at 25 ℃ using an Ubbelohde viscometer on a 0.2g/dL solution of the copolymer in N, N-dimethylformamide. The reduced viscosity of the graft copolymer was measured using acetone-soluble substances obtained after acetone extraction in the measurement of the graft ratio.

< viscosity average molecular weight >

The intrinsic viscosity [ eta ] at 20 ℃ was measured with a Ubbelohde viscometer with respect to a methylene chloride solution of a polycarbonate resin, and the viscosity average molecular weight (Mv) was calculated by the following formula.

[η]=1.23×10^-4×(Mv)^0.83

< volume average particle diameter, proportion of particles having particle diameter of 200nm or less >

The measurement was carried out by a dynamic light scattering method using Nanotrac UPA-EX150 manufactured by Nikkiso K.K.

< melt volume flow Rate >

The melt volume flow rate of the thermoplastic resin composition was measured by a method based on ISO1133 under conditions of a barrel temperature of 220 ℃ and a load of 98N. The melt volume flow rate is a reference for the flowability of the thermoplastic resin composition.

< Charpy impact Strength >

The charpy impact strength of the molded article was measured by a method based on ISO 179 for a test piece having a V notch left in an atmosphere at 23 ℃ for 12 hours or more.

< flexural modulus >

The flexural modulus of the molded article was measured by a method based on ISO test method 178 at a measurement temperature of 23 ℃ and a test piece thickness of 4 mm.

< temperature of deformation under load >

The deformation temperature under load of the molded article was measured by the flat drawing method (フラットワイズ method) at 1.83MPa and 4mm according to ISO test method 75.

< gloss >

The gloss of the surface of the molded article was determined from the reflectance at an incident angle of 60 ℃ and a reflection angle of 60 ℃ by using a digital variable angle gloss meter UGV-5D manufactured by Suga tester, wherein the thermoplastic resin composition was injection-molded (injection speed: 40g/sec.) into a molding plate of 100 mm. times.100 mm. times.3 mm.

However, in examples 11 to 28 and comparative examples 3 to 5, the gloss was determined on the surface of each of 100X 2mm flat test pieces obtained by injection molding at injection speeds of 10g/sec. and 40g/sec. in the same manner as described above.

< color rendering >

A thermoplastic resin composition was injection-molded (injection speed: 40g/sec.) into a 100mm X3 mm molded plate, and L was measured using a colorimeter CM-508D manufactured by Meinenda. The smaller the value of L, the better the color rendering property.

However, in examples 11 to 28 and comparative examples 3 to 5, the color developability was measured in the same manner as described above for the surfaces of 100X 2mm flat test pieces obtained by injection molding at injection speeds of 10g/sec. and 40g/sec.

[ Synthesis example 1: production of acid group-containing copolymer emulsion (K)

The following were charged into a reactor equipped with a reagent injection vessel, a cooling tube, a jacket heater, and a stirring device under nitrogen purge:

200 parts of deionized water (hereinafter referred to as water),

2 portions of potassium oleate,

4 parts of dioctyl sodium sulfosuccinate,

0.003 part of ferrous sulfate heptahydrate,

0.009 part of ethylene diamine tetraacetic acid disodium,

0.3 part of sodium formaldehyde sulfoxylate,

the temperature was raised to 60 ℃. From the time of reaching 60 ℃, continuously dropwise adding the mixture for 120 minutes

82 parts of n-butyl acrylate,

18 parts of methacrylic acid,

0.5 part of cumene hydroperoxide

A mixture of constituents. After completion of the dropwise addition, the mixture was further aged at 60 ℃ for 2 hours to obtain an acid group-containing copolymer emulsion (K) having a solid content of 33%, a polymerization conversion of 96% and a volume average particle diameter of the acid group-containing copolymer of 150 nm.

[ Synthesis example 2: production of rubber Polymer emulsion (a-1)

< paragraph 1 >

The following were charged into a reactor equipped with a reagent injection vessel, a cooling tube, a jacket heater, and a stirring device while stirring:

310 portions of water,

1 part of dipotassium alkenylsuccinate (ラテムル ASK, manufactured by Kao corporation),

80 parts of n-butyl acrylate,

0.48 part of allyl methacrylate,

0.4 part of triallyl isocyanurate,

0.2 part of tert-butyl hydroperoxide,

after the nitrogen gas in the reactor was replaced, the contents were heated. At an internal temperature of 55 ℃, adding

0.3 part of sodium formaldehyde sulfoxylate,

0.0001 part of ferrous sulfate heptahydrate,

0.0003 part of disodium ethylene diamine tetraacetate,

10 portions of water

The resulting aqueous solution starts polymerization. After confirming the exothermic heat of polymerization, the jacket temperature was set to 75 ℃ and the polymerization was continued until confirming that the exothermic heat of polymerization was not generated, and the reaction was further maintained for 1 hour. The volume average particle diameter of the resulting rubbery polymer was 100 nm. To this, 1 part by solid content of a 5% sodium pyrophosphate aqueous solution (pH of the mixed solution was 9.1) was added, and the jacket temperature was controlled so that the internal temperature was 70 ℃.

The acid group-containing copolymer emulsion (K) was added at an internal temperature of 70 ℃ in an amount of 3 parts by solid content, and the mixture was stirred for 30 minutes while the internal temperature was maintained at 70 ℃ to increase the fertilizer. The volume average particle size after the enlargement is 420 nm.

< paragraph 2 >

At an internal temperature of 70 ℃ is added

0.03 portion of sodium formaldehyde sulfoxylate,

0.002 parts of ferrous sulfate heptahydrate,

0.006 part of disodium ethylene diamine tetraacetate,

80 portions of water

The resulting aqueous solution was then added dropwise over 1 hour

20 parts of n-butyl acrylate,

0.12 part of allyl methacrylate,

0.1 part of triallyl isocyanurate,

0.02 portion of tert-butyl hydroperoxide

Forming a mixed solution. After completion of the dropwise addition, the mixture was kept at 70 ℃ for 1 hour and then cooled to obtain a rubbery polymer emulsion (a-1) having a solid content of 18% and a volume average particle diameter of the rubbery polymer of 450 nm. The polymerization conversion was 97%, and the proportion of particles having a particle diameter of 200nm or less was 10%.

[ Synthesis example 3: production of rubber Polymer emulsions (a-2) to (a-5) and rubber Polymer emulsions (x-1) to (x-2)

Rubber polymer emulsions (a-2) to (a-5) and rubber polymer emulsions (x-1) to (x-2) were obtained in the same manner as in Synthesis example 2 except that allyl methacrylate and triallyl isocyanurate were used in amounts shown in Table 1.

[ Synthesis example 4: production of rubber Polymer emulsion (a-6)

Rubber polymer emulsion (a-6) was obtained in the same manner as in synthesis example 2, except that the 5% sodium pyrophosphate aqueous solution added for increasing the viscosity was changed to 2 parts by solid content and the acid group-containing copolymer emulsion (K) was changed to 3 parts by solid content. The volume average particle diameter after the enlargement was 510nm, and the volume average particle diameter after the polymerization of 20 parts of n-butyl acrylate was 550 nm.

[ Synthesis example 5: production of rubber Polymer emulsion (a-7)

A rubbery polymer emulsion (a-7) was obtained in the same manner as in Synthesis example 2 except that the 5% sodium pyrophosphate aqueous solution added for increasing the viscosity of the emulsion was changed to 1 part by solid content and the acid group-containing copolymer emulsion (K) was changed to 4 parts by solid content. The volume average particle diameter after the enlargement is 325nm, and the volume average particle diameter after 20 parts of polymerized n-butyl acrylate is 350 nm.

[ Synthesis example 6: production of rubber Polymer emulsion (a-8)

Rubber polymer emulsion (a-8) was obtained in the same manner as in Synthesis example 2 except that the amount of monomers and the like initially charged was set to the amount shown in Table 1 and polymerization of n-butyl acrylate and the like was not carried out after enlargement, and the volume average particle diameter after enlargement was 430 nm.

[ Synthesis example 7: production of rubber Polymer emulsion (a-9)

A rubbery polymer emulsion (a-9) was obtained in the same manner as in Synthesis example 2 except that the 5% sodium pyrophosphate aqueous solution added for increasing the viscosity of the emulsion was changed to 3 parts by solid content and the acid group-containing copolymer emulsion (K) was changed to 3 parts by solid content. The volume average particle diameter after the enlargement is 600nm, and the volume average particle diameter after 20 parts of polymerized n-butyl acrylate is 650 nm.

[ Synthesis example 8: production of rubber Polymer emulsion (a-10)

A rubbery polymer emulsion (a-10) was obtained in the same manner as in Synthesis example 2 except that the amount of the 5% aqueous solution of sodium pyrophosphate added for increasing the viscosity of the emulsion was changed to 1 part by solid content and the amount of the acid group-containing copolymer emulsion (K) was changed to 5 parts by solid content. The volume average particle diameter after the enlargement is 280nm, and the volume average particle diameter after 20 parts of polymerized n-butyl acrylate is 300 nm.

The conditions for synthesizing the rubber polymer emulsions (a-1) to (a-10) and (x-1) to (x-2), the particle diameters of the resulting rubber polymers, and the like are shown in Table 1.

[ Table 1]

BA: acrylic acid n-butyl ester

AMA: allyl methacrylate

TAIC: triallylisocyanurate

BDMA: 1, 3-butanediol dimethacrylate

In addition, the method is as follows: relative to 100 parts by mass of acrylate monomers

In addition, 2: mass% based on 100 mass% of the total amount of the polyfunctional monomers

[ example 1: production of graft copolymer (A-1)

A reactor equipped with a reagent injection container, a cooling tube, a jacket heater, and a stirring device was charged with:

230 portions of water (containing the water in the rubber polymer emulsion),

50 parts (by solid content) of rubber polymer emulsion (a-1),

0.5 part of dipotassium alkenylsuccinate (ラテムル ASK, manufactured by Kao corporation),

0.3 part of sodium formaldehyde sulfoxylate,

after the reactor was fully charged with nitrogen gas, the internal temperature was raised to 70 ℃ with stirring.

Then, the mixture was added dropwise over 100 minutes

15 portions of acrylonitrile,

35 portions of styrene,

0.5 part of tert-butyl hydroperoxide

The temperature was raised to 80 ℃ while forming a mixed solution.

After completion of the dropwise addition, the reaction mixture was kept at 80 ℃ for 30 minutes and then cooled to obtain an emulsion of the graft copolymer (A-1).

Next, 100 parts of a 1.5% aqueous sulfuric acid solution was heated to 80 ℃ and 100 parts of the graft copolymer (A-1) emulsion was slowly dropped into the aqueous solution while stirring the aqueous solution to solidify the graft copolymer, and the temperature was further raised to 95 ℃ and held for 10 minutes.

Then, the cured product was dehydrated, washed, and dried to obtain a powdery graft copolymer (A-1).

[ examples 2 to 10, comparative examples 1 to 2]

Powdery graft copolymers (A-2) to (A-10) and (X-1) to (X-2) were obtained in the same manner as in example 1 except that the rubber polymer emulsion used was changed to those shown in Table 2.

Table 2 shows the synthesis conditions and the evaluation results of the physical properties of the graft copolymers (A-2) to (A-10) and (X-1) to (X-2).

[ Table 2]

[ Synthesis example 9: production of graft copolymer (B-1)

The following were charged into a reactor equipped with a reagent injection vessel, a cooling tube, a jacket heater, and a stirring device while stirring:

240 portions of water,

0.7 part of dipotassium alkenylsuccinate (ラテムル ASK, manufactured by Kao corporation),

50 parts of n-butyl acrylate,

0.15 part of allyl methacrylate,

0.05 part of 1, 3-butanediol dimethacrylate,

0.1 part of tert-butyl hydroperoxide,

after the inside of the reactor was replaced with nitrogen, the contents were heated.

At an internal temperature of 55 ℃ is added

0.2 part of sodium formaldehyde sulfoxylate,

0.00015 part of ferrous sulfate heptahydrate,

0.00045 part of disodium ethylene diamine tetraacetate,

10 portions of water

The resulting aqueous solution starts polymerization. After confirming the exothermic heat of polymerization, the jacket temperature was set to 75 ℃ and the polymerization was continued until confirming that the exothermic heat of polymerization was not generated, and the reaction was further maintained for 1 hour. The time from the confirmation of the exothermic reaction of polymerization to the completion of the non-exothermic reaction was 20 minutes, and the polymerization conversion at the time of the non-exothermic reaction was 92% and the polymerization rate was 4.6%/minute. The volume average particle diameter of the resulting rubbery polymer was 105 nm.

Controlling the internal temperature at 70 ℃, adding

0.2 part of dipotassium alkenylsuccinate (ラテムル ASK, manufactured by Kao corporation),

0.3 part of sodium formaldehyde sulfoxylate,

0.001 part of ferrous sulfate heptahydrate,

0.003 part of disodium ethylene diamine tetraacetate,

10 portions of water

And (3) forming an aqueous solution. Then, it was added dropwise over 80 minutes

12 portions of acrylonitrile,

28 parts of styrene,

0.2 part of tert-butyl hydroperoxide

The temperature of the resulting mixture was simultaneously raised to 80 ℃.

After the completion of the dropwise addition, the mixture was cooled to 75 ℃ after keeping the temperature at 80 ℃ for 30 minutes, and was added dropwise over 20 minutes

3 portions of acrylonitrile,

7 portions of styrene,

0.02 part of n-octyl mercaptan,

0.05 part of tert-butyl hydroperoxide

Forming a mixed solution. After completion of the dropwise addition, the mixture was held at 75 ℃ for 60 minutes and then cooled to obtain an emulsion of the graft copolymer (B-1).

Then, 100 parts of a 2.0% sulfuric acid aqueous solution was heated to 40 ℃ and 100 parts of the graft copolymer (B-1) emulsion was slowly dropped into the aqueous solution while stirring the aqueous solution to solidify the graft copolymer, and the temperature was further raised to 95 ℃ and held for 10 minutes.

Then, the cured product was dehydrated, washed, and dried to obtain a powdery graft copolymer (B-1).

[ Synthesis example 10: production of graft copolymer (B-2)

A graft copolymer (B-2) was obtained in the same manner as in Synthesis example 9, except that the amount of dipotassium alkenylsuccinate added in the polymerization of n-butyl acrylate was changed to 0.3 part.

The time from the confirmation of the exothermic reaction of polymerization of n-butyl acrylate to the completion of no exothermic reaction was 22 minutes, and the polymerization conversion at the completion of no exothermic reaction was 94% and the polymerization rate was 4.3%/minute. The volume average particle diameter of the rubbery polymer was 155 nm.

[ Synthesis example 11: production of graft copolymer (B-3)

A powdery graft copolymer (B-3) was obtained in the same manner as in synthesis example 9, except that 0.0000375 parts of ferrous sulfate heptahydrate and 0.0001125 parts of disodium ethylenediaminetetraacetate were used in the polymerization of n-butyl acrylate.

The time from the confirmation of the heat release to the completion of the heat release of n-butyl acrylate polymerization was 40 minutes, and the polymerization conversion at the completion of the heat release was 91% and the polymerization rate was 2.3%/minute. The volume average particle diameter was 130 nm.

Table 3 shows the synthesis conditions and the evaluation results of the physical properties of the graft copolymers (B-1) to (B-3).

[ Table 3]

AMA: allyl methacrylate

BDMA: 1, 3-butanediol dimethacrylate

In addition, the method is as follows: relative to 100 parts by mass of acrylate monomers

[ Synthesis example 12: production of thermoplastic resins (C-1) and (C-2)

The copolymers (C-1) and (C-2) having the compositions and reduced viscosities shown in Table 4 were obtained by a known suspension polymerization method to prepare thermoplastic resins (C-1) and (C-2).

[ Synthesis example 13: production of thermoplastic resin (C-3)

A copolymer (C-3) having the composition and reduced viscosity shown in Table 4 was obtained by a known continuous solution polymerization method to prepare a thermoplastic resin (C-3).

[ Synthesis example 14: production of thermoplastic resin (C-4)

A copolymer (C-4) having the composition and reduced viscosity shown in Table 4 was obtained by a known suspension polymerization method to prepare a thermoplastic resin (C-4).

Further, as the thermoplastic resin (C-5), a polycarbonate resin (Ipiplon S-3000 (viscosity average molecular weight (Mv): 21,000), manufactured by Mitsubishi engineering plastics Co., Ltd.) was used.

The monomer compositions and reduced viscosities of the copolymers (C-1) to (C-4) are shown in Table 4.

[ Table 4]

AN: acrylonitrile

ST: styrene (meth) acrylic acid ester

AMS: alpha-methylstyrene

PMID: n-phenylmaleimide

MMA: methacrylic acid methyl ester

MA: acrylic acid methyl ester

[ example 11: production of thermoplastic resin composition

16 parts of the graft copolymer (A-1), 24 parts of the graft copolymer (B-1), 30 parts of the thermoplastic resin (C-2), 0.5 part of ethylenebisstearylamide, 0.5 part of ADKSTAB LA-63PK (manufactured by Asahi Denka Co., Ltd.), and 1 part of carbon black # 960 (manufactured by Mitsubishi chemical) as a colorant were mixed in a Henschel mixer, and the mixture was shaped by a devolatilization twin-screw extruder (manufactured by Nippon Steel Co., Ltd., TEX 30. alpha.) heated to 240 ℃ at a cylinder temperature to prepare pellets. The melt volume flow rate was determined for the particles. The results are shown in Table 5.

The resin pellets were molded at 220 to 260 ℃ by a 4-Angstrom injection molding machine (manufactured by Japan Steel works Ltd.) to prepare a desired sample, and the Charpy impact strength, flexural modulus and load deformation temperature were measured. Then, the glossiness and color developing property were measured on the surface of a 100X 2mm flat test piece obtained by injection molding at injection speeds of 10g/sec. and 40g/sec. These results are shown in Table 5.

Examples 12 to 28 and comparative examples 3 to 5: production of thermoplastic resin composition

Pellets of a thermoplastic resin composition were obtained in the same manner as in example 11, except that the compounding ratios of the acrylic rubber-based graft copolymer (a), the acrylic rubber-based graft copolymer (B), the graft copolymer (X) and the thermoplastic resin (C) were changed to the compounding ratios shown in table 5. The evaluation results of the physical properties are shown in Table 5.

[ Table 5]

[ Observation ]

The following matters are apparent from Table 5.

That is, comparative example 3 using the acrylic rubber-based graft copolymer (X-1) was poor in gloss and color development and poor in appearance, and the acrylic rubber-based graft copolymer (X-1) did not contain allyl methacrylate units of a polyfunctional monomer having 2 unsaturated bonds, which is an essential component in the present invention. Further, comparative example 4 using the acrylic rubber-based graft copolymer (X-2) was poor in balance among impact strength, gloss and color developability, and the acrylic rubber-based graft copolymer (X-2) did not contain a triallyl isocyanurate unit of a polyfunctional monomer having 3 unsaturated bonds. Further, comparative example 5, which does not contain the acrylic rubber-based graft copolymer (A) of the present invention, has a poor balance between impact strength and flexural modulus. In addition, the difference in gloss and color development was large between the low-speed molding and the high-speed molding in all of the comparative examples, indicating that the injection speed dependence was high.

On the other hand, the thermoplastic resin compositions of the present invention of examples 11 to 28 containing the acrylic rubber-based graft copolymer (A) of the present invention exhibited good properties in terms of mechanical strength such as impact strength and flexural modulus, and appearance such as glossiness and color development property.

Examples 29 to 44 and comparative examples 6 to 8: production of thermoplastic resin composition

Pellets of a thermoplastic resin composition were obtained in the same manner as in example 11 except that the thermoplastic resins (C-1) and (C-2) in example 11 were changed to the thermoplastic resin (C-4) which is a (meth) acrylic resin, and the compounding ratios of the acrylic rubber graft copolymer (A), the acrylic rubber graft copolymer (B), the graft copolymer (X) and the thermoplastic resin (C) were changed to those shown in Table 5. The evaluation results of the physical properties are shown in Table 6.

[ Table 6]

[ Observation ]

The following matters are apparent from Table 6.

That is, comparative example 6 using the acrylic rubber-based graft copolymer (X-1) was poor in gloss and color development and poor in appearance, and the acrylic rubber-based graft copolymer (X-1) did not contain allyl methacrylate units of a polyfunctional monomer having 2 unsaturated bonds, which is an essential component in the present invention. Further, comparative example 7 using the acrylic rubber-based graft copolymer (X-2) was poor in balance among impact strength, gloss and color developability, and the acrylic rubber-based graft copolymer (X-2) did not contain a triallyl isocyanurate unit of a polyfunctional monomer having 3 unsaturated bonds. Further, comparative example 8, which did not contain the acrylic rubber-based graft copolymer (A) of the present invention, had a poor balance between impact strength and flexural modulus.

On the other hand, the thermoplastic resin compositions of the present invention in examples 29 to 44 containing the acrylic rubber-based graft copolymer (A) of the present invention exhibited good properties in terms of mechanical strength such as impact strength and flexural modulus, and appearance such as gloss and color development even when the (meth) acrylic resin (C-4) was used as the thermoplastic resin (C).

Example 45: production of thermoplastic resin composition

6 parts of the graft copolymer (A-1), 9 parts of the graft copolymer (B-1), 45 parts of the thermoplastic resin (C-1), 40 parts of the thermoplastic resin (C-5), 0.5 part of paraffin wax, 0.5 part of ADKSTAB LA-63PK (manufactured by Asahi Denka Co., Ltd.) and 1 part of carbon black # 960 (manufactured by Mitsubishi chemical) as a colorant were mixed by a Henschel mixer, and the mixture was shaped by a devolatilizing twin-screw extruder (manufactured by Nippon Steel Co., Ltd., TEX 30. alpha.) heated to 250 ℃. The melt volume flow rate was determined for the particles. The results are shown in Table 7.

The resin pellets were molded at 250 to 270 ℃ by a 4-Angstrom (オンス) injection molding machine (manufactured by Japan Steel works, Ltd.) to prepare a desired sample, and the Charpy impact strength, flexural modulus, load deformation temperature, gloss and color development were measured. These results are shown in Table 7.

Examples 46 to 63 and comparative examples 9 to 12: production of thermoplastic resin composition

Pellets of a thermoplastic resin composition were obtained in the same manner as in example 45 except that the compounding ratios of the acrylic rubber-based graft copolymer (A), the acrylic rubber-based graft copolymer (B), the graft copolymer (X), the thermoplastic resins (C-1) and (C-5) were changed to the compounding ratios shown in Table 7. The evaluation results of the physical properties are shown in Table 7.

[ Table 7]

[ Observation ]

The following matters are apparent from Table 7.

That is, comparative example 9 using the acrylic rubber-based graft copolymer (X-1) was poor in gloss and color developability and poor in appearance, and the acrylic rubber-based graft copolymer (X-1) did not contain allyl methacrylate units of a polyfunctional monomer having 2 unsaturated bonds, which is an essential component in the present invention. Further, comparative example 10 using the acrylic rubber-based graft copolymer (X-2) was poor in balance among impact strength, gloss and color developability, and the acrylic rubber-based graft copolymer (X-2) did not contain a triallyl isocyanurate unit of a polyfunctional monomer having 3 unsaturated bonds. Further, comparative example 11, which did not contain the acrylic rubber-based graft copolymer (A) of the present invention, had a poor balance between impact strength and flexural modulus. In addition, in the thermoplastic resin composition of rubber polymer total amount of comparative example 12, the impact strength reduction is significant.

On the other hand, the thermoplastic resin compositions of the present invention in examples 45 to 63 containing the acrylic rubber-based graft copolymer (A) of the present invention exhibited good properties in terms of mechanical strength such as impact strength and flexural modulus, and appearance such as gloss and color development even when the styrene-based resin (C-1) and the polycarbonate resin (C-5) were used as the thermoplastic resin (C).

Industrial applicability

The acrylic rubber-based graft copolymer (A) and the thermoplastic resin composition of the present invention have an excellent balance among impact resistance, rigidity and appearance. Further, since they are also excellent in weather resistance, they are suitably used for automobile material applications, building material applications, and home appliance applications which have been used in recent years.

While the invention has been described in detail and with reference to specific embodiments thereof, it will be apparent to one skilled in the art that various changes can be made therein without departing from the spirit and scope thereof.

It should be noted that the present application is incorporated by reference in its entirety based on japanese patent application (japanese patent application 2011-072129) filed on 29/3.2011.

Claims (9)

1. An acrylic rubber graft copolymer obtained by graft-polymerizing a vinyl monomer in the presence of a rubber polymer containing an acrylate monomer unit and a polyfunctional monomer unit, wherein the total amount of the polyfunctional monomer units in the rubber polymer is 0.3 to 3 parts by mass per 100 parts by mass of the acrylate monomer unit, and the total amount of the polyfunctional monomer units 100% by mass contains 30 to 95% by mass of a polyfunctional monomer unit having 2 unsaturated bonds and 5 to 70% by mass of a polyfunctional monomer unit having 3 unsaturated bonds,

the polyfunctional monomer unit having 2 unsaturated bonds is selected from allyl methacrylate, 2-propenyl acrylate and divinylbenzene, and

the polyfunctional monomer unit having 3 unsaturated bonds is selected from triallyl isocyanurate, triallyl cyanurate, and triallyl trimellitate having an aromatic ring.

2. The acrylic rubber-based graft copolymer according to claim 1, wherein the rubbery polymer is obtained by mixing a copolymer emulsion obtained by polymerizing a monomer mixture containing an acrylate-based monomer and a polyfunctional monomer with an acid-group-containing copolymer emulsion to thereby thicken the polymer, and then further adding a monomer including an acrylate-based monomer to the copolymer emulsion to thereby polymerize the polymer.

3. The acrylic rubber-based graft copolymer according to claim 1 or 2, wherein the volume average particle diameter of the rubbery polymer is 300nm to 600 nm.

4. A thermoplastic resin composition comprising the acrylic rubber-based graft copolymer according to any one of claims 1 to 3, which is hereinafter referred to as an acrylic rubber-based graft copolymer (A).

5. The thermoplastic resin composition according to claim 4, wherein the composition comprises an acrylic rubber-based graft copolymer (A) obtained by graft-polymerizing a vinyl monomer in the presence of a rubbery polymer containing an acrylate-based monomer unit having a volume average particle diameter of 70 to 200nm, and an acrylic rubber-based graft copolymer (B) described below.

6. The thermoplastic resin composition according to claim 5, wherein the total amount of the rubber polymer contained in the thermoplastic resin composition is 5 to 30 parts by mass, based on 100 parts by mass of the resin component in the thermoplastic resin composition, and wherein the rubber polymer contained in the acrylic rubber graft copolymer (A) is 20 to 70% by mass, and the rubber polymer contained in the acrylic rubber graft copolymer (B) is 30 to 80% by mass, based on 100% by mass of the total amount of the rubber polymer contained in the thermoplastic resin composition.

7. The thermoplastic resin composition according to claim 5 or 6, wherein the composition contains 0 to 90 parts by mass of the thermoplastic resin (C) other than the acrylic rubber-based graft copolymer (A) and the acrylic rubber-based graft copolymer (B).

8. The thermoplastic resin composition according to claim 5 or 6, wherein the acrylic rubber-based graft copolymer (B) is obtained by polymerizing 100 mass% of an acrylic monomer at a polymerization rate of 3 mass%/min or more.

9. A molded article of a thermoplastic resin composition, which is obtained by molding the thermoplastic resin composition according to any one of claims 4 to 8.