Polymer and method for producing the same

Abstract

To provide a polymer having superior heat resistance and being particularly useful as a modifier for imparting impact strength.SOLUTION: A polymer contains a rubber-containing polymer portion (P1) and a polymer portion (P2) provided with structural units originating from a silane coupling agent, the polymer portion (P2) being arranged on the outer side of the rubber-containing polymer portion (P1). The polymer is obtained by polymerizing an emulsion polymerization latex containing a specific rubber with a vinyl monomer (a) that includes a vinyl monomer (a1) having a reactive group, and reacting a silane coupling agent (b) with the reactive group of the resulting polymer (A), such that structural units derived from the silane coupling agent are introduced into the outer polymer portion (P2). This enables provision of a polymer having superior heat resistance and being particularly useful as a modifier for imparting impact strength.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a polymer and a method for producing the same. [Background technology]

[0002] Graft copolymers, in which vinyl monomers are graft-polymerized onto rubber-containing polymers, can be dispersed in a wide variety of resins while maintaining the specified rubber particle size and rubber structure, and are therefore suitable for use as modifiers in resins that require impact strength.

[0003] The molding temperature during the production of resin products varies depending on the type of matrix resin, and since the molding temperature often becomes high, the modifiers used must also have excellent heat resistance. As an example of a method for improving the thermal decomposition temperature, Patent Document 1 discloses adding a small amount of a polyalkyl acrylate component to the polyalkyl methacrylate component of the graft portion, thereby suppressing depolymerization of the polyalkyl methacrylate component. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-19349 Summary of the Invention [Problem to be solved by the invention]

[0005] However, simply adding a polyalkyl acrylate component as in Patent Document 1 may not be effective enough to improve the thermal decomposition temperature.

[0006] A primary object of the present invention is to provide a polymer having excellent heat resistance, which is particularly useful as a modifier for imparting impact strength, and a method for producing said polymer. [Means for solving the problem]

[0007] As a result of intensive research to solve the above problems, the present inventors have discovered that excellent heat resistance can be obtained by introducing a polyorganosiloxane component into the outer polymer portion of a rubber-containing polymer, and have completed the present invention.

[0008] That is, the present invention includes the following aspects. [1] A rubber-containing polymer portion (P1) and a polymer portion (P2) having a structural unit derived from a silane coupling agent, A polymer wherein the polymer portion (P2) is outside the rubber-containing polymer portion (P1). [2] The polymer according to [1], wherein the rubber-containing polymer portion (P1) contains at least one rubber selected from the group consisting of butadiene rubber, silicone rubber, and acrylic rubber. [3] The polymer according to [1] or [2], wherein the polymer has a soluble fraction in acetone or tetrahydrofuran of 60 mass % or less. [4] The polymer according to any one of [1] to [3], wherein the silane coupling agent is a compound represented by the following formula (1): [ka] (In the formula (1), R 1 ~R 3 are each independently an alkyl group having 1 to 4 carbon atoms. 4 is a hydrogen atom or a monovalent organic group, and n is an integer of 1 or greater. [5] R in the formula (1) 4 is a hydrogen atom, an amino group, an epoxy group, an alkyl group, a vinyl group, a thiol group, or a ureido group. [6] The polymer according to any one of [1] to [5], which is a graft copolymer having the polymer portion (P2) as a graft portion. [7] The polymer according to any one of [1] to [6], wherein the content of the polymer portion (P2) is 0.1 to 20 parts by mass per 100 parts by mass of the rubber-containing polymer portion (P1). [8] The polymer according to any one of [1] to [7], wherein the maximum value of tan δ of the polymer in a temperature range of 80 to 120°C is 0.5 or less. [9] A step of polymerizing an emulsion polymerization latex containing at least one selected from the group consisting of butadiene rubber, silicone rubber, and acrylic rubber with a vinyl monomer (a) containing a vinyl monomer (a1) having a reactive group that reacts with a silane coupling agent to obtain a latex of a polymer (A); and a step of reacting the reactive group of the polymer (A) with a silane coupling agent (b) to obtain a polymer (B).

[10] The method for producing a polymer according to [9], further comprising a step of coagulating and recovering the polymer (A) in a latex with a coagulant and then redispersing it in water before reacting the polymer (A) with the silane coupling agent (b). [Effects of the Invention]

[0009] According to the present invention, there are provided polymers having excellent heat resistance, which are particularly useful as modifiers for imparting impact strength, and a method for producing said polymers. DETAILED DESCRIPTION OF THE INVENTION

[0010] The following definitions of terms are used herein: The term "structural unit" refers to a structural unit derived from a monomer, i.e., a structural unit formed by polymerizing a monomer, or a structural unit in which a portion of the structural unit is converted into a different structure by treating the polymer. "(Meth)acrylate" is a general term for acrylate and methacrylate. A numerical range indicated by "to" means a numerical range that includes the numbers before and after "to" as the lower and upper limits. The numerical ranges of the contents, various physical property values, and property values ​​disclosed in this specification can be arbitrarily combined with the lower and upper limits to form new numerical ranges.

[0011] <Polymer> The polymer according to the embodiment contains a rubber-containing polymer portion (P1) and a polymer portion (P2) having a structural unit derived from a silane coupling agent, and the polymer portion (P2) is located outside the rubber-containing polymer portion (P1). The polymer according to the embodiment is typically a graft copolymer (CSR) in which a polymer portion (P2) forming a shell structure is bonded as a Kraft portion to a core portion that is a rubber-containing polymer portion (P1).

[0012] [Rubber-containing polymer portion (P1)] The rubber-containing polymer portion (P1) preferably contains at least one selected from the group consisting of butadiene rubber, silicone rubber and acrylic rubber, since this has a high effect of improving impact strength.

[0013] (butadiene rubber) The butadiene rubber may be, for example, a copolymer of 1,3-butadiene and one or more vinyl monomers copolymerizable with 1,3-butadiene. Examples of vinyl monomers copolymerizable with 1,3-butadiene include styrene, α-methylstyrene, vinyltoluene, etc. These vinyl monomers may be used alone or in combination of two or more.

[0014] The content of the 1,3-butadiene-derived structural units in the butadiene rubber is preferably 60% by mass or more, more preferably 65% ​​by mass or more, based on the total structural units of the butadiene rubber. When the content of the 1,3-butadiene-derived structural units is equal to or more than the lower limit, the effect of improving impact strength is further enhanced.

[0015] (silicone rubber) Examples of silicone rubber include polyorganosiloxane rubber and polyorganosiloxane composite rubber. The polyorganosiloxane rubber is obtained by emulsion polymerization of an organosiloxane mixture (monomer component) containing an organosiloxane, a polyorganosiloxane graft crosslinking agent (hereinafter also referred to as "siloxane crosslinking agent"), and a siloxane oligomer having a terminal blocking group. If necessary, a polyorganosiloxane crosslinking agent (hereinafter also referred to as "siloxane crosslinking agent") may be used in the polyorganosiloxane rubber.

[0016] The organosiloxane may be either a chain organosiloxane or a cyclic organosiloxane, with cyclic organosiloxanes being preferred due to their high polymerization stability and high polymerization rate. As the cyclic organosiloxane, a cyclic organosiloxane having a 3- or greater ring is preferred, and a cyclic organosiloxane having a 3- to 6-membered ring is more preferred.

[0017] Examples of cyclic organosiloxanes include hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, trimethyltriphenylcyclotrisiloxane, tetramethyltetraphenylcyclotetrasiloxane, octaphenylcyclotetrasiloxane, etc. One type of cyclic organosiloxane may be used alone, or two or more types may be used in combination.

[0018] The siloxane crosslinking agent is preferably one that can bond with the organosiloxane via a siloxane bond and form a bond with the vinyl monomer. In consideration of reactivity with the organosiloxane, an alkoxysilane compound having a vinyl group is preferred. By using a siloxane crosslinking agent, it is possible to obtain a polyorganosiloxane having a functional group polymerizable with any vinyl monomer.

[0019] Examples of siloxane crosslinking agents include β-methacryloyloxyethyl dimethoxymethylsilane, γ-methacryloyloxypropyl methoxydimethylsilane, γ-methacryloyloxypropyl dimethoxymethylsilane, γ-methacryloyloxypropyl trimethoxysilane, γ-methacryloyloxypropyl ethoxydiethylsilane, γ-methacryloyloxypropyl diethoxymethylsilane, δ-methacryloyloxybutyl diethoxymethylsilane, vinylphenylethyl dimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, γ-mercaptopropyl dimethoxymethylsilane, γ-mercaptopropyl methoxydimethylsilane, γ-mercaptopropyl diethoxymethylsilane, γ-mercaptopropyl ethoxydimethylsilane, γ-mercaptopropyl trimethoxysilane, etc. One type of siloxane crosslinking agent may be used alone, or two or more types may be used in combination.

[0020] The siloxane crosslinking agent preferably has three or four functional groups capable of bonding with organosiloxane. Examples of the siloxane crosslinking agent include trialkoxyalkylsilanes such as trimethoxymethylsilane; trialkoxyarylsilanes such as triethoxyphenylsilane; and tetraalkoxysilanes such as tetramethoxysilane, tetraethoxysilane, tetra-n-propoxysilane, and tetrabutoxysilane. One type of siloxane crosslinking agent may be used alone, or two or more types may be used in combination.

[0021] The siloxane oligomer having a terminal blocking group refers to a siloxane oligomer that has an alkyl group or the like at the end of the organosiloxane oligomer and terminates the polymerization of the polyorganosiloxane. Examples of siloxane oligomers having a terminal blocking group include hexamethyldisiloxane, 1,3-bis(3-glycidoxypropyl)tetramethyldisiloxane, 1,3-bis(3-aminopropyl)tetramethyldisiloxane, methoxytrimethylsilane, etc. These may be used alone or in combination of two or more.

[0022] The content of organosiloxane in the organosiloxane mixture (100% by mass) is preferably 60 to 99.9% by mass, more preferably 70 to 99.9% by mass. The content of the siloxane crosslinking agent in the organosiloxane mixture (100% by mass) is preferably 0.1 to 10% by mass. The content of the siloxane crosslinking agent in the organosiloxane mixture (100% by mass) is preferably 0 to 30% by mass.

[0023] The polyorganosiloxane composite rubber contains a polyorganosiloxane rubber and a vinyl polymer for composite rubber, and preferably contains a polyorganosiloxane rubber and a polyalkyl (meth)acrylate rubber.

[0024] The vinyl polymer for composite rubber can be obtained by polymerizing a vinyl monomer for composite rubber and, if necessary, a crosslinking monomer or an acrylic crosslinking agent. Examples of vinyl monomers for composite rubbers include alkyl acrylates such as methyl acrylate, ethyl acrylate, n-propyl acrylate, and n-butyl acrylate; alkyl methacrylates such as methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, and i-butyl methacrylate; aromatic vinyl monomers such as styrene and α-methylstyrene; and vinyl cyanide monomers such as acrylonitrile and methacrylonitrile. Among these, n-butyl acrylate is preferred because of its high impact strength improving effect. One type of vinyl monomer for composite rubber may be used alone, or two or more types may be used in combination.

[0025] The crosslinkable monomer is a polyfunctional monomer having two or more polymerizable unsaturated bonds. Specific examples include allyl methacrylate, triallyl cyanurate, triallyl isocyanurate, divinylbenzene, ethylene glycol dimethacrylate, propylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, 1,4-butylene glycol dimethacrylate, 1,6-hexanediol diacrylate, and triallyl trimellitate. The crosslinkable monomer may be used alone or in combination of two or more.

[0026] Acrylic crosslinking agents are multifunctional monomers with two or more polymerizable unsaturated bonds of different reactivity. By having groups with different reactivities, they are incorporated into the composite rubber while preserving the unsaturated groups when polymerized with other components, enabling the formation of a graft copolymer. Examples include allyl methacrylate, triallyl cyanurate, and triallyl isocyanurate. One type of acrylic crosslinking agent may be used alone, or two or more types may be used in combination. The acrylic crosslinking agent has two or more polymerizable unsaturated bonds, similar to the crosslinkable monomer, and therefore also functions as a crosslinking agent.

[0027] The content of the polyorganosiloxane rubber in the polyorganosiloxane composite rubber is preferably 0.1 to 99.9 mass %, more preferably 5 to 99.9 mass %, and even more preferably 7 to 99.9 mass %, based on the total mass of the polyorganosiloxane composite rubber.

[0028] The content of the structural units derived from the crosslinkable monomer is preferably 0 to 15 parts, more preferably 0.1 to 10 parts, per 100 parts by mass of the structural units derived from the vinyl monomer for the composite rubber. The content of the structural units derived from the acrylic crosslinking agent is preferably 0 to 15 parts, more preferably 0.1 to 10 parts, per 100 parts by mass of the structural units derived from the vinyl monomer for the composite rubber.

[0029] (acrylic rubber) Examples of the acrylic rubber include a homopolymer or copolymer of alkyl (meth)acrylate. Examples of alkyl (meth)acrylates include alkyl acrylates such as methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, ethoxyethoxyethyl acrylate, methoxytripropylene glycol acrylate, and 4-hydroxybutyl acrylate; and alkyl methacrylates such as hexyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, tridecyl methacrylate, and stearyl methacrylate. These alkyl (meth)acrylates may be used alone or in combination of two or more.

[0030] The acrylic rubber may contain a small amount of structural units derived from monomers other than alkyl (meth)acrylate. Examples of other monomers include aromatic alkenyl compounds such as styrene, α-methylstyrene, and vinyltoluene, vinyl cyanide compounds such as acrylonitrile and methacrylonitrile, and methacrylic group-modified silicones. These other monomers may be used alone or in combination of two or more.

[0031] The acrylic rubber may contain at least one of a crosslinking agent and a grafting agent, if necessary. Examples of the crosslinking agent include ethylene glycol dimethacrylate, propylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, 1,4-butylene glycol dimethacrylate, divinylbenzene, polyfunctional methacrylic group-modified silicone, etc. One type of crosslinking agent may be used alone, or two or more types may be used in combination.

[0032] Examples of grafting agents include allyl methacrylate, triallyl cyanurate, and triallyl isocyanurate. Allyl methacrylate can also be used as a crosslinking agent. The grafting agents may be used alone or in combination of two or more.

[0033] The acrylic rubber is preferably an acrylic rubber whose main component is a structural unit derived from n-butyl acrylate, where "main component is a structural unit derived from n-butyl acrylate" means that the proportion of the structural units derived from n-butyl acrylate to the total structural units of the acrylic rubber is 50% by mass or more, preferably 60% by mass or more, and more preferably 70% by mass or more. One example is an acrylic rubber containing 0.1 to 3 parts by mass of structural units derived from allyl methacrylate per 100 parts by mass of structural units derived from n-butyl acrylate, and an acrylic rubber containing 0.1 to 0.7 parts by mass of structural units derived from allyl methacrylate per 100 parts by mass of structural units derived from n-butyl acrylate is preferred.

[0034] The content of the rubber-containing polymer portion (P1) in the polymer according to the embodiment is preferably 30 to 95% by mass, more preferably 40 to 95% by mass, even more preferably 40 to 90% by mass, and particularly preferably 50 to 90% by mass. When the content of the rubber-containing polymer portion (P1) is equal to or greater than the lower limit, the effect of improving impact strength is likely to be obtained. When the content of the rubber-containing polymer portion (P1) is equal to or less than the upper limit, the dispersibility in the molding material is likely to be improved.

[0035] The particle size of the rubber-containing polymer portion (P1) in the polymer according to this embodiment is not particularly limited, but is preferably, for example, 30 to 800 nm, more preferably 50 to 600 nm. The method for measuring the particle size is not particularly limited, but may be, for example, measured by the method described in the Examples below.

[0036] [Polymer part (P2)] The polymer portion (P2) has a structural unit derived from a silane coupling agent. A preferred example of the polymer portion (P2) is a polymer portion in which the graft portion contains a structural unit derived from a vinyl monomer (a1) having a reactive group reactive with a silane coupling agent, and a polyorganosiloxane component consisting of a structural unit derived from the silane coupling agent is bonded to the reactive group. The polymer portion (P2) can be formed by graft polymerizing a vinyl monomer (a) containing a vinyl monomer (a1) having a reactive group reactive with a silane coupling agent onto the rubber-containing polymer portion (P1), and then reacting the reactive group with a silane coupling agent to introduce a structural unit derived from the silane coupling agent into the graft portion.

[0037] Examples of the reactive group that reacts with a silane coupling agent include an alkoxysilyl group and a hydroxyl group. Examples of the vinyl monomer (a1) include an alkoxysilyl group-containing vinyl monomer, a hydroxyl group-containing vinyl monomer, etc. The vinyl monomer (a1) may be used alone or in combination of two or more kinds.

[0038] The alkoxysilyl group-containing vinyl monomer is not particularly limited, and examples thereof include alkoxysilyl group-containing (meth)acrylates such as 3-(trimethoxysilyl)propyl methacrylate and 3-(triethoxysilyl)propyl methacrylate. The hydroxyl group-containing vinyl monomer is not particularly limited, and examples thereof include hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and 6-hydroxyhexyl (meth)acrylate.

[0039] The polymer portion (P2) is not particularly limited to a structural unit derived from the vinyl monomer (a), and examples thereof include various vinyl-based monomers such as a (meth)acrylate monomer, an aromatic vinyl monomer, and a vinyl cyanide monomer.

[0040] Examples of the (meth)acrylate monomer include alkyl methacrylates such as methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, and i-butyl methacrylate; and alkyl acrylates such as methyl acrylate, ethyl acrylate, and n-butyl acrylate. Examples of aromatic vinyl monomers include styrene, alkyl-substituted styrenes (p-methylstyrene, m-methylstyrene, o-methylstyrene, 2,4-dimethylstyrene, 2,5-dimethylstyrene, 3,4-dimethylstyrene, 3,5-dimethylstyrene, p-ethylstyrene, m-ethylstyrene, o-ethylstyrene, etc.), alkyl-substituted isopropenylbenzenes (isopropenylbenzene (α-methylstyrene), isopropenyltoluene, isopropenylethylbenzene, isopropenylpropylbenzene, isopropenylbutylbenzene, isopropenylpentylbenzene, isopropenylhexylbenzene, isopropenyloctylbenzene, etc.), 1,1-diphenylethylene, etc. Among these, styrene and α-methylstyrene are preferred because they can suppress the generation of cullets. Examples of vinyl cyanide monomers include acrylonitrile and methacrylonitrile. These may be used alone or in combination of two or more.

[0041] The vinyl monomer (a) preferably contains at least one selected from the group consisting of (meth)acrylate monomers and aromatic vinyl monomers, in order to provide a molded article with superior weather resistance. Among the (meth)acrylate monomers and aromatic vinyl monomers, it is more preferable to contain either or both of methyl methacrylate and styrene, in order to provide a molded article with particularly superior weather resistance.

[0042] The silane coupling agent is preferably a compound represented by the following formula (1).

[0043] [ka]

[0044] In the formula (1), R 1 ~R 3 are each independently an alkyl group having 1 to 4 carbon atoms. 4 is a hydrogen atom or a monovalent organic group, and n is an integer of 1 or greater.

[0045] R 1 ~R 3 may be the same group or different groups. R 1 ~R 3 The alkyl group may be a straight chain or a branched chain. R 1 ~R 3 Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an s-butyl group, and a t-butyl group, and from the viewpoint of reactivity, a methyl group and an ethyl group are preferred.

[0046] R 4 The organic group is not particularly limited and can be selected depending on the application. Examples include amino groups, epoxy groups, alkyl groups, vinyl groups, thiol groups, and ureido groups. From the viewpoint of compatibility with the type of molding material, amino groups and alkyl groups are preferred. R 4 The amino group may be composed of an alkylamino group or a phenylamino group. Specific examples of the alkylamino group include a methylamino group, an ethylamino group, a dimethylamino group, a diethylamino group, and a methylethylamino group. Specific examples of the phenylamino group include a monophenylamino group, a diphenylamino group, and a triphenylamino group, and the phenyl group may or may not have a substituent. R 4 The epoxy group may be an alicyclic epoxy group or a glycidoxy group. R 4 The vinyl group may be composed of a methacryl group or an acrylic group. R 4 The alkyl group of R may be a straight chain or a branched chain. 4The alkyl group preferably has 1 to 10 carbon atoms, and more preferably has 1 to 8 carbon atoms. n is preferably 1 to 8, and more preferably 1 to 5.

[0047] Specific examples of the silane coupling agent include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, methyltrimethoxysilane, ethyltrimethoxysilane, n-propyltrimethoxysilane, isopropyltrimethoxysilane, n-butyltrimethoxysilane, isobutyltrimethoxysilane, pentyltrimethoxysilane, n-hexyltrimethoxysilane, n-octyltrimethoxysilane, isooctyltrimethoxysilane, and n-decyltrimethoxysilane. Examples of suitable compounds include trimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, (3-mercaptopropyl)trimethoxysilane, 3-ureidopropyltriethoxysilane, 5,6-epoxyhexyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, and 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane. The silane coupling agents may be used alone or in combination of two or more.

[0048] The content of the polymer portion (P2) in the polymer according to the embodiment is preferably 5 to 200 parts by mass, more preferably 10 to 150 parts by mass, and even more preferably 10 to 100 parts by mass, relative to 100 parts by mass of the rubber-containing polymer portion (P1). When the content of the polymer portion (P2) is equal to or greater than the lower limit, improved dispersibility in the molding material is likely to be obtained. When the content of the polymer portion (P2) is equal to or less than the upper limit, the proportion of the rubber-containing polymer portion (P1) increases relatively, and therefore improved impact strength is likely to be obtained.

[0049] The total content of the structural units derived from the (meth)acrylate monomer and the aromatic vinyl monomer in the polymer portion (P2) is preferably 30 to 99.5 mass%, more preferably 40 to 99 mass%, even more preferably 50 to 99 mass%, and particularly preferably 50 to 97 mass%, relative to 100 mass% of the total of the structural units derived from all the vinyl monomers (a). The total content of structural units derived from methyl methacrylate and styrene in the polymer portion (P2) is preferably 30 to 99.5 mass%, more preferably 40 to 99 mass%, even more preferably 50 to 99 mass%, and particularly preferably 50 to 97 mass%, relative to 100 mass% of the total of structural units derived from all vinyl monomers (a).

[0050] The content of the structural units derived from the vinyl monomer (a1) in the polymer portion (P2) (however, including structural units in which a silane coupling agent is bonded to a reactive group) is preferably 0.5 to 70 mass%, more preferably 1 to 60 mass%, even more preferably 1 to 50 mass%, and particularly preferably 3 to 50 mass%, relative to 100 mass% in total of all structural units derived from the vinyl monomer (a).

[0051] The amount of silane coupling agent (SCA) introduced into the polymer according to the present embodiment is preferably 0.05 to 2 [mmol / 1g-CSR] per 1g of polymer (CSR), more preferably 0.05 to 1 [mmol / 1g-CSR], and even more preferably 0.1 to 1 [mmol / 1g-CSR]. When the amount of SCA introduced is equal to or greater than the lower limit, the effect of improving heat resistance is easily obtained. When the amount of SCA introduced is equal to or less than the upper limit, dispersibility in the molding material is easily obtained.

[0052] The amount of SCA introduced is a value determined by the method described in the Examples. Thermogravimetry (TG) was performed on the polymer before and after reaction with the silane coupling agent, and the weight fraction of the undecomposed material remaining when the temperature was raised to 550°C at a heating rate of 10°C / min was measured. The difference in weight fraction of the undecomposed material between the polymer before and after reaction with the silane coupling agent, ΔTG, was then calculated. Using the estimated molecular weight of the undecomposed material (SiO2) (60.08g / mol), the amount of SCA introduced [mmol / 1g-CSR] was calculated from the formula: SCA introduction amount = ΔTG / 100 / 60.08×1000.

[0053] The acetone soluble fraction of the polymer at 56°C is preferably 60% by mass or less, more preferably 0.1 to 50% by mass, even more preferably 0.1 to 40% by mass, and particularly preferably 0.1 to 35% by mass. When the acetone soluble fraction is equal to or less than the upper limit, the effect of improving impact strength is more excellent. When the acetone soluble fraction is equal to or more than the lower limit, fluidity is more likely to be maintained during the molding process. For the same reasons as for the acetone soluble content, the polymer has a tetrahydrofuran soluble content at 25°C of preferably 60% by mass or less, more preferably 0.1 to 50% by mass, even more preferably 0.1 to 40% by mass, and particularly preferably 0.1 to 35% by mass.

[0054] The soluble fraction of the polymer is measured by the following method. Weigh out 1 g of dry polymer powder as a sample and add it to 50 mL of acetone or tetrahydrofuran. Mix thoroughly, then heat under reflux at 56°C for 4 hours in the case of acetone, or leave it overnight at 25°C in the case of tetrahydrofuran to extract the soluble matter. The soluble solution is then recovered by centrifugation, and the solvent in the recovered soluble solution is evaporated and vacuum dried to obtain a dry soluble powder. The mass (g) of the dry soluble powder is measured, and the soluble fraction is calculated from the mass ratio to 1 g of dry powder of the sample.

[0055] The maximum value of tan δ of the polymer according to the embodiment in the temperature range of 80 to 120°C is preferably 0.5 or less, more preferably 0.45 or less, and even more preferably 0.4 or less. If the maximum value of tan δ is equal to or less than the upper limit, the effect of improving impact strength is more excellent. On the other hand, the lower limit of the maximum value of tan δ is not particularly limited, but is preferably, for example, 0.01 or more. The tan δ is measured by the following method. A polymer is press-molded to prepare a sample of approximately 1.5 mm diameter. The sample is heated from -70°C to 150°C at a rate of 2°C / min in a nitrogen atmosphere, while applying a 1 Hz sine wave to measure the dynamic viscoelasticity. The elastic modulus E' and E" measured at each temperature are used to calculate tan δ = E" / E'.

[0056] [Action and effect] The polymer according to the embodiment described above has a silane coupling agent-derived structural unit introduced into the polymer portion (P2) outside the rubber-containing polymer portion (P1), and therefore exhibits excellent heat resistance in addition to the effect of improving impact strength. Therefore, the polymer according to the embodiment is useful as a modifier for matrix resins that are molded at high temperatures.

[0057] <Method of producing polymer> The method for producing a polymer according to the embodiment includes the following polymerization step and coupling step. Polymerization step: A latex of polymer (A) is obtained by polymerizing an emulsion polymerization latex containing at least one rubber selected from the group consisting of butadiene rubber, silicone rubber, and acrylic rubber with a vinyl monomer (a) containing a vinyl monomer (a1) having a reactive group that reacts with a silane coupling agent. Coupling step: A silane coupling agent (b) is reacted with the reactive group of the polymer (A) to obtain a polymer (B).

[0058] In the method for producing a polymer according to the embodiment, if the pH of the emulsion in which the coupling reaction is carried out becomes high, the emulsion becomes unstable. In this case, the method may further include the following recovery and re-dispersion step. Recovery and re-dispersion step: Before reacting the polymer (A) with the silane coupling agent (b), the polymer (A) in the latex is coagulated and recovered with a coagulant, and then re-dispersed in water. Each step will be described below.

[0059] [Polymerization process] In the polymerization step, an emulsion polymerization latex containing at least one rubber selected from the group consisting of butadiene rubber, silicone rubber, and acrylic rubber is polymerized with a vinyl monomer (a) to produce a polymer (A) having a reactive group that reacts with a silane coupling agent. The polymer (A) obtained in this polymerization step is a rubber-containing polymer having a core-shell structure, and is typically a graft copolymer having a rubber portion (core portion) made of at least one rubber selected from the group consisting of butadiene rubber, silicone rubber, and acrylic rubber, and a polymer chain consisting of structural units derived from the vinyl monomer (a) as a graft portion (shell portion).

[0060] The Tg of a polymer made of vinyl monomer (a) can be determined by the FOX formula. In this case, the Tg of a homopolymer of each vinyl monomer constituting vinyl monomer (a) can be, for example, the value described in "POLYMER HANDBOOK" (Wiley Interscience, 1999). The Tg of a homopolymer of a vinyl monomer not described in this document can be calculated using Bicerano's method, "Prediction of Polymer Properties" (Marcel Dekker, 2002).

[0061] The emulsion-polymerized latex containing at least one rubber selected from the group consisting of butadiene rubber, silicone rubber, and acrylic rubber can be produced by emulsion-polymerizing the monomer components used in the production of each rubber.

[0062] As the emulsifier, an anionic emulsifier or a nonionic emulsifier is preferred. Examples of anionic emulsifiers include sodium alkylbenzenesulfonate, sodium alkyldiphenyletherdisulfonate, sodium alkylsulfate, sodium polyoxyethylene alkylsulfate, and sodium polyoxyethylene nonylphenylether sulfate. Examples of nonionic emulsifiers include polyoxyethylene alkyl ethers, polyoxyethylene alkylene alkyl ethers, polyoxyethylene distyrenated phenyl ethers, polyoxyethylene tribenzyl phenyl ethers, and polyoxyethylene polyoxypropylene glycols. The emulsifier may be used alone or in combination of two or more kinds.

[0063] The polymerization initiator is not particularly limited, and known polymerization initiators can be used, such as persulfates, peroxides, azo initiators, redox initiators in which persulfates are combined with a reducing agent, and redox initiators in which organic peroxides are combined with a reducing agent. The polymerization initiator may be used alone or in combination of two or more kinds.

[0064] Examples of peroxides include inorganic peroxides such as hydrogen peroxide, potassium persulfate, and ammonium persulfate; and organic peroxides such as diisopropylbenzene hydroperoxide, p-menthane hydroperoxide, cumene hydroperoxide, t-butyl hydroperoxide, succinic acid peroxide, t-butyl peroxyneodecanoate, t-butyl peroxyneoheptanoate, t-butyl peroxypivalate, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, and t-butylperoxy-2-ethylhexanoate. The peroxides may be used alone or in combination of two or more.

[0065] Examples of the azo initiator include oil-soluble azo initiators such as 2,2'-azobisisobutyronitrile, dimethyl 2,2'-azobis(2-methylpropionate), 2,2'-azobis(2,4-dimethylvaleronitrile), and 2,2'-azobis(2-butyronitrile); and water-soluble azo initiators such as 4,4'-azobis(4-cyanovaleric acid), 2,2'-azobis[N-(2-carboxymethyl)-2-methylpropionamidine]hydrate, 2,2'-azobis-(N,N'-dimethyleneisobutylamidine) dihydrochloride, and 2,2'-azobis[2-(2-imidazolin-2-yl)propane] dihydrochloride. The azo initiators may be used alone or in combination of two or more.

[0066] When an organic peroxide is combined with a reducing agent to form a redox initiator, it is preferable to use the above organic peroxide in combination with a reducing agent such as sodium formaldehyde sulfoxylate, L-ascorbic acid, fructose, dextrose, sorbose, or inositol, and ferrous sulfate·ethylenediaminetetraacetic acid disodium salt. The reducing agent may be used alone or in combination of two or more kinds.

[0067] The amount of emulsifier used is preferably 0.05 to 10 parts by mass, more preferably 0.1 to 5 parts by mass, even more preferably 0.5 to 5 parts by mass, and particularly preferably 1 to 2.5 parts by mass, per 100 parts by mass of the monomer components used for various rubbers. The rubber particle size can be adjusted to a desired value by adjusting the amount of emulsifier used. The amount of the polymerization initiator used is preferably 0.01 to 1 part by mass relative to 100 parts by mass of the monomer components used in the various rubbers. When a peroxide is used as a polymerization initiator, the amount of the peroxide used is preferably, for example, 0.01 to 1 part by mass per 100 parts by mass of the monomer components used for the various rubbers. From the viewpoint of outgassing resistance, the amount of the reducing agent used is preferably 0.01 to 1 part by mass per 100 parts by mass of the monomer components used in the various rubbers.

[0068] The polymerization temperature is not particularly limited and can be set to, for example, 30 to 100°C. The polymerization time is not particularly limited and can be, for example, 3 to 30 hours.

[0069] The polymerization of the emulsion-polymerized latex containing at least one rubber selected from the group consisting of butadiene rubber, silicone rubber, and acrylic rubber with the vinyl monomer (a) is carried out by emulsion polymerization. For example, a method of adding vinyl monomer (a) to emulsion-polymerized latex maintained at polymerization temperature and polymerizing in one or multiple stages can be mentioned. In the case of multiple-stage polymerization, it is preferable to divide the total amount of vinyl monomer (a) used in the presence of emulsion-polymerized latex and add it successively or continuously to carry out polymerization. Such a polymerization method has good polymerization stability and can stably produce a latex having a desired particle size and particle size distribution.

[0070] The vinyl monomer (a) preferably contains at least one selected from the group consisting of various vinyl monomers such as (meth)acrylate monomers, aromatic vinyl monomers, and vinyl cyanide monomers, and further contains a vinyl monomer (a1). The (meth)acrylate monomers, aromatic vinyl monomers, vinyl cyanide monomers, and vinyl monomer (a1) are as described above. The amount of vinyl monomer (a) used is preferably 5 to 200 parts by mass, more preferably 10 to 150 parts by mass, and even more preferably 10 to 100 parts by mass, per 100 parts by mass of the rubber component in the emulsion polymerized latex.

[0071] The total proportion of the (meth)acrylate monomer and the aromatic vinyl monomer in the vinyl monomer (a) is preferably 30 to 99.5 mass%, more preferably 40 to 99 mass%, even more preferably 50 to 99 mass%, and particularly preferably 50 to 97 mass%, based on the total mass of the vinyl monomer (a). The proportion of the vinyl monomer (a1) in the vinyl monomer (a) is preferably 0.5 to 70 mass%, more preferably 1 to 60 mass%, further preferably 1 to 50 mass%, particularly preferably 3 to 50 mass%, based on the total mass of the vinyl monomer (a).

[0072] The glass transition temperature (Tg) of the polymer made of the vinyl monomer (a) to be graft-polymerized is preferably 70 to 105°C, more preferably 80 to 105°C, and even more preferably 90 to 105°C. When the glass transition temperature of the polymer made of the vinyl monomer (a) is equal to or higher than the lower limit, the powder properties such as the flowability and particle size of the polymer are improved. When the glass transition temperature of the polymer made of the vinyl monomer (a) is equal to or lower than the upper limit, the particle size can be controlled appropriately so as to maintain the handleability of the powder.

[0073] During polymerization of the graft portion, an emulsifier can be added as needed. Examples of the emulsifier used for polymerization of the graft portion include the same emulsifiers as those used in producing the rubber, and anionic emulsifiers and nonionic emulsifiers are preferred. The polymerization initiator used for the polymerization of the graft portion may be the same as the polymerization initiator used in producing the rubber, and azo-based initiators and redox-based initiators are preferred.

[0074] The polymerization temperature of the emulsion-polymerized latex and the vinyl monomer (a) is not particularly limited, and can be, for example, 30 to 100°C. The polymerization time of the emulsion polymerized latex and the vinyl monomer (a) is not particularly limited, and can be, for example, 3 to 30 hours.

[0075] [Recovery and re-dispersion process] If necessary, the polymer (A) is coagulated from the polymer (A) latex by emulsion polymerization, recovered, and re-dispersed in water. Examples of a method for recovering the polymer (A) include a method in which the polymer (A) latex is introduced into hot water in which a coagulant is dissolved to coagulate the polymer (A), and the coagulated polymer is filtered and dehydrated.

[0076] Examples of coagulants include inorganic salts such as aluminum chloride, aluminum sulfate, sodium sulfate, magnesium sulfate, sodium nitrate, and calcium acetate; and acids such as sulfuric acid. Among these, calcium acetate is particularly preferred. One type of coagulant may be used alone, or two or more types may be used in combination.

[0077] The amount of water used during redispersion is not particularly limited, and can be, for example, 300 to 1000 parts by mass per 100 parts by mass of the polymer (A).

[0078] [Coupling process] In the coupling step, for example, an aqueous solution of a silane coupling agent is added to the polymer (A) latex or redispersion of the polymer (A) after emulsion polymerization, and the mixture is heated to carry out a coupling reaction, thereby obtaining a polymer (B) in which structural units derived from the silane coupling agent are introduced into the graft moieties of the polymer (A). In the resulting polymer (B), the rubber portion is the rubber-containing polymer portion (P1), and the graft portion into which the structural unit derived from the silane coupling agent has been introduced is the polymer portion (P2).

[0079] The amount of the silane coupling agent used is preferably 0.1 to 40 parts by mass, more preferably 0.5 to 30 parts by mass, and even more preferably 0.5 to 20 parts by mass, per 100 parts by mass of the polymer (A). When the amount of the silane coupling agent used is equal to or greater than the lower limit, a polymer (B) having excellent heat resistance is easily obtained. When the amount of the silane coupling agent used is equal to or less than the upper limit, the inherent characteristics of the polymer (A), such as impact resistance, are easily maintained.

[0080] The reaction temperature for the coupling reaction is not particularly limited, and can be set to, for example, 25 to 80°C. The reaction time for the coupling reaction is not particularly limited and can be, for example, 0.5 to 24 hours.

[0081] If necessary, the pH of the reaction solution may be adjusted during or after the coupling reaction, for example, by adding an acid or alkali to adjust the pH to the range of 4.0 to 8.0. Examples of the acid include acetic acid and sulfuric acid. Examples of alkalis include sodium carbonate and sodium hydroxide.

[0082] The polymer (B) after the coupling reaction can be obtained as a powder by, for example, coagulation, i.e., coagulation and recovery with a coagulant and drying, or by drying with a spray drying method or freeze drying method. Coagulation and recovery with a coagulant can be carried out in the same manner as described in the recovery and dispersion step. Among these, drying by spray drying or coagulation is preferred. When coagulation is performed, impurities such as the emulsifier used in the emulsion polymerization can be easily removed, making it easier to obtain a powder of polymer (B) with high purity. When the recovery and dispersion step is performed, impurities such as the emulsifier are sufficiently removed, so a method of filtering and drying the reaction solution after the coupling reaction may be adopted.

[0083] [Action and effect] As described above, according to the method for producing a polymer according to the embodiment, structural units derived from a silane coupling agent are introduced into the grafted portion on the outer side of the rubber portion. This results in a polymer (B) that not only has improved impact strength but also has excellent heat resistance. This polymer (B) is particularly useful as a modifier for matrix resins that are molded at high temperatures. One example of using the present invention for molding a matrix resin is a method in which pelletized thermoplastic resin and, if necessary, additives are mixed using an extruder, extruded into strands, and cut into pellets using a rotary cutter or the like. This method can produce a pelletized resin composition. The resulting pelletized resin composition can then be molded using a molding method such as injection molding, extrusion molding, blow molding, or calendar molding to produce a molded product. [Example]

[0084] The present invention will be described in detail below with reference to examples, but the present invention is not limited to the following descriptions. In the following description, "parts" and "%" mean "parts by mass" and "% by mass" unless otherwise specified.

[0085] <Evaluation method> Various evaluation methods are described below. [Core-shell rubber evaluation] (1) Solids A mass w1 of the core-shell rubber latex was dried in a hot air dryer at 180°C for 30 minutes, and the mass w2 of the residue after drying was measured, and the solid content [%] was calculated by the following formula (2). Solid content [%] = w2 / w1 × 100 (2)

[0086] (2) Polymerization rate The polymerization rate was calculated from the mass w3 of all monomers charged when producing the core-shell rubber and the mass w4 of the solid content obtained after polymerization according to the following formula (3). Polymerization rate [%]=w4 / w3×100 (3)

[0087] (3) Particle size A solution of core-shell rubber latex prepared with deionized water to a concentration (solid content) of 0.5 g / L was measured for absorbance DA at a wavelength of 700 nm using an ultraviolet-visible spectrophotometer (Shimadzu Corporation, UV-mini1240), and the particle size was calculated using the following formula (4). Particle size [nm]=1000×10 0.4379×log(DA)-0.4160 ···(4)

[0088] [Evaluation of graft copolymers] (4)ΔTG Thermogravimetry (TG) was performed on the dry powder of the graft copolymer using a thermal analyzer (STA200, manufactured by Hitachi High-Technologies Corporation) to measure the weight fraction of undecomposed material remaining when the temperature was raised to 550°C at a heating rate of 10°C / min. ΔTG was calculated using the following formula (5) from the weight fraction TG1 of the undecomposed material measured for the graft copolymer (core-shell rubber) before the coupling reaction with the silane coupling agent and the weight fraction TG2 of the undecomposed material measured for the graft copolymer after the coupling reaction. ΔTG [%] = TG2 - TG1 (5)

[0089] (5) Amount of SCA (silane coupling agent) introduced The amount of SCA introduced was calculated from the ΔTG determined by the thermogravimetry and the molecular weight (60.08 g / mol) of the estimated undecomposed material (SiO 2 ) according to the following formula (6). Amount of SCA introduced [mmol / 1g-CSR]=ΔTG / 100 / 60.08×1000 (6)

[0090] (6) Thermal decomposition temperatures Td5 and Td10 The above-mentioned thermogravimetric measurement was performed on the dry powder of the graft copolymer after the coupling reaction, and the temperature at which the weight fraction decreased by 5% during the heating process was defined as Td5, and the temperature at which the weight fraction decreased by 10% was defined as Td10.

[0091] (7) Soluble fraction 1 g of the dried powder of the graft copolymer after the coupling reaction and 50 mL of tetrahydrofuran solvent were weighed and placed in a metal cell designed for centrifugation, and the mixture was left standing overnight at 25°C to extract the soluble matter. The metal cell was placed in a centrifuge and centrifuged, after which the soluble matter solution was recovered. The solvent in the recovered soluble matter solution was evaporated and vacuum-dried to obtain a dry powder of the soluble matter. The soluble matter percentage was calculated from the mass of the dry powder of the soluble matter.

[0092] (8) tanδ After the coupling reaction, 10 g of the dried powder of the graft copolymer was placed in a mold and preheated for 2 minutes at a temperature of 160 to 200°C using a press molding machine (manufactured by Shoji Iron Works Co., Ltd.), and then pressed for 8 minutes at a pressure of 5 MPa. The mold was then removed from the press molding machine and cooled to obtain a press-molded piece with a thickness of approximately 1.5 mm. The press-molded pieces were cut to an appropriate size and placed on a tensile jig of a dynamic viscoelasticity apparatus (Hitachi High-Tech Science Corporation). Measurements were performed by applying a sine wave with a frequency of 1 Hz while raising the temperature from -70°C to 150°C at a rate of 2°C / min in a nitrogen atmosphere. From the elastic moduli E' and E" measured at each temperature, tan δ was calculated using the following formula (6), and the maximum value of tan δ and the temperature at which this occurred were determined. Tan δ reaches a maximum value in the temperature range of the glass transition temperature of the shell (graft) composition (generally 80 to 140°C). tanδ=E” / E' (6)

[0093] <Production of core-shell rubber> [Production Example 1] Production of core-shell rubber (A-1) A 5-liter separable flask equipped with a stirring blade and a cooling condenser was charged with an aqueous solution of 1 part (solids equivalent) of sodium dodecylbenzenesulfonate (Neopelex G15, manufactured by Kao Corporation, product name: Neopelex G-15) dissolved in 250 parts of deionized water. Next, 69 parts of n-butyl acrylate (n-BA), 1 part of allyl methacrylate (AMA), and 0.3 parts of tert-butyl hydroperoxide (tBH, manufactured by NOF Corporation, product name: Perbutyl® H) were added. A nitrogen stream was passed through the flask while stirring to replace the atmosphere inside the flask, and the liquid temperature was raised to 55°C. An aqueous solution of 0.001 parts of ferrous sulfate, 0.003 parts of ethylenediaminetetraacetic acid disodium salt, and 0.24 parts of Rongalit dissolved in 5 parts of deionized water was added to initiate radical polymerization. Thereafter, the liquid temperature was raised to 70°C and maintained at this temperature for 1 hour to complete the polymerization, thereby obtaining an acrylic rubber latex.

[0094] While maintaining the temperature of the acrylic rubber latex at 70°C, 30 parts of methyl methacrylate (MMA) was added dropwise to the latex over 60 minutes to polymerize it. After the dropwise addition was completed, the liquid temperature was maintained at 70°C for 1 hour and then cooled to 25°C to obtain a core-shell rubber (A-1) latex.

[0095] [Production Examples 2 to 4] Production of core-shell rubbers (A-2) to (A-4) An acrylic rubber latex was obtained in the same manner as in Production Example 1. A 5% aqueous solution of sodium hydroxide was added to the obtained acrylic rubber latex to neutralize the latex so that the pH value of the latex became 7. Thereafter, monomers were added dropwise and polymerized in the same manner as in Production Example 1, except that the monomer compositions shown in Table 1 were used, to obtain core-shell rubber (A-2) to (A-4) latexes.

[0096] Table 1 shows the evaluation results of the core-shell rubber (A-2) to (A-4) latexes.

[0097] [Table 1]

[0098] The abbreviations in Table 1 have the following meanings: n-BA: n-butyl acrylate AMA: Allyl methacrylate MMA: Methyl methacrylate MPS: 3-(trimethoxysilyl)propyl methacrylate (Tokyo Chemical Industry Co., Ltd.)

[0099] <Production of Graft Copolymer> [Example 1] A 1-liter separable flask equipped with a stirring blade and a cooling condenser was charged with 100 parts (solids equivalent) of core-shell rubber (A-2) latex. Next, an aqueous solution of 5 parts of 3-aminopropyltrimethoxysilane (APTMS, manufactured by Tokyo Chemical Industry Co., Ltd.) as a silane coupling agent dissolved in 100 parts of deionized water was added, and the liquid temperature was raised to 80°C while stirring to initiate the reaction. After this, the mixture was held for 4 hours, and acetic acid was added to neutralize the mixture to a pH of 7, yielding a graft copolymer latex. Next, 400 parts of the polymer latex was gradually added dropwise to 1200 parts of a 0.6% aqueous calcium acetate solution maintained at 60°C while stirring, causing coagulation. The water temperature was then raised to 90°C, and the mixture was stirred for 5 minutes to cause coagulation. The resulting coagulated powder was filtered and dehydrated. The dehydrated wet powder was dried overnight in a dryer at 80°C to obtain a graft copolymer powder.

[0100] [Example 2] Graft copolymer powder was obtained in the same manner as in Example 1, except that the amount of silane coupling agent added was changed to the conditions shown in Table 2.

[0101] [Example 3] While stirring 2000 parts of a 0.6% aqueous solution of calcium acetate maintained at a temperature of 60°C, 700 parts of the core-shell rubber (A-3) latex was gradually added dropwise to cause coagulation. The water temperature was then raised to 90°C, and the mixture was stirred for 5 minutes to cause coagulation. The resulting coagulated powder was filtered and dehydrated. After dehydration, 100 parts of the wet powder (solids equivalent) were placed in a 2-liter separable flask equipped with a stirring blade and a cooling condenser, and 300 parts of deionized water were added and redispersed by stirring. Next, an aqueous solution of 10 parts of 3-aminopropyltrimethoxysilane (APTMS, manufactured by Tokyo Chemical Industry Co., Ltd.) as a silane coupling agent in 20 parts of deionized water was added to the dispersion, and the liquid temperature was raised to 80°C while stirring to initiate the reaction. After cooling for 4 hours, the dispersion was filtered and dehydrated. The dehydrated wet powder was dried overnight in a dryer at 80°C to obtain a graft copolymer powder.

[0102] [Example 4] A graft copolymer powder was obtained in the same manner as in Example 3, except that the core-shell rubber (A-3) latex was changed to the core-shell rubber (A-4) latex.

[0103] [Example 5] Coagulation, coagulation, filtration, and dehydration were performed in the same manner as in Example 3, except that the core-shell rubber (A-3) latex was replaced with the core-shell rubber (A-4) latex, and the latex was redispersed in deionized water. Next, an aqueous solution containing 10 parts of n-octyltrimethoxysilane (OTMS, manufactured by Tokyo Chemical Industry Co., Ltd.) as a silane coupling agent, 40 parts of ethanol, and 0.04 parts of acetic acid dissolved in 20 parts of deionized water was added to the dispersion, and the liquid temperature was raised to 80°C while stirring to initiate the reaction. After cooling for 4 hours, the dispersion was filtered and dehydrated. The dehydrated wet powder was dried overnight in a dryer at 80°C to obtain a graft copolymer powder.

[0104] [Comparative Example 1] 700 parts of the core-shell rubber (A-1) latex was gradually added dropwise to 2000 parts of a 0.6% aqueous calcium acetate solution maintained at 60°C while stirring to cause coagulation. The water temperature was then raised to 90°C, and the mixture was stirred for 5 minutes to cause coagulation. The obtained coagulated powder was filtered and dehydrated. The dehydrated wet powder was dried overnight in a dryer at 80°C to obtain a powder of the core-shell rubber (A-1). The powder of the core-shell rubber (A-1) was evaluated in the same manner as the evaluation of the powder of the graft copolymer in Example 1.

[0105] Table 2 shows the evaluation results of the graft copolymers obtained in the examples and comparative examples.

[0106] [Table 2]

[0107] As shown in Table 2, the graft copolymers of Examples 1 to 5 had high thermal decomposition temperatures and excellent heat resistance because they contained polymer moieties (P2) with structural units derived from a silane coupling agent on the outer surface. In addition, they had low tan δ values ​​and exhibited elastic behavior above the glass transition temperature. On the other hand, the core-shell rubber of Comparative Example 1 did not contain the polymer portion (P2) having a structural unit derived from a silane coupling agent, and therefore had a low thermal decomposition temperature and poor heat resistance. In addition, it showed a high tan δ value and exhibited viscous behavior above the glass transition temperature.

Claims

1. The composition contains a rubber-containing polymer portion (P1) and a polymer portion (P2) having a structural unit derived from a silane coupling agent, A polymer wherein the polymer portion (P2) is outside the rubber-containing polymer portion (P1).

2. The polymer according to claim 1, wherein the rubber-containing polymer portion (P1) comprises at least one rubber selected from the group consisting of butadiene rubber, silicone rubber, and acrylic rubber.

3. The polymer according to claim 1 or 2, wherein the polymer has a soluble fraction in acetone or tetrahydrofuran of 60 mass % or less.

4. The polymer according to claim 1 or 2, wherein the silane coupling agent is a compound represented by the following formula (1): 【Chemical 1】 (In the formula (1), R １ ~R ３ are each independently an alkyl group having 1 to 4 carbon atoms. ４ is a hydrogen atom or a monovalent organic group, and n is an integer of 1 or more.

5. R in the formula (1) ４ The polymer according to claim 4, wherein is a hydrogen atom, an amino group, an epoxy group, an alkyl group, a vinyl group, a thiol group, or a ureido group.

6. The polymer according to claim 1 or 2, which is a graft copolymer having the polymer portion (P2) as a graft portion.

7. 3. The polymer according to claim 1, wherein the content of the polymer portion (P2) is 0.1 to 20 parts by mass per 100 parts by mass of the rubber-containing polymer portion (P1).

8. 3. The polymer according to claim 1, wherein the maximum value of tan δ of the polymer in the temperature range of 80 to 120° C. is 0.5 or less.

9. a step of polymerizing an emulsion-polymerized latex containing at least one rubber selected from the group consisting of butadiene rubber, silicone rubber, and acrylic rubber with a vinyl monomer (a) containing a vinyl monomer (a1) having a reactive group that reacts with a silane coupling agent to obtain a latex of a polymer (A); and a step of reacting the reactive group of the polymer (A) with a silane coupling agent (b) to obtain a polymer (B).

10. The method for producing a polymer according to claim 9, further comprising the step of coagulating and recovering the polymer (A) in a latex with a coagulant and then redispersing the polymer (A) in water before reacting the polymer (A) with the silane coupling agent (b).

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