Method for producing polymer, composition, and molded article

Abstract

To provide a polymer production method capable of producing a polymer in which yellowing is suppressed, as well as a novel composition and a molded article comprising the composition.SOLUTION: A method for producing a polymer comprises polymerizing a radically polymerizable monomer component (M) comprising a monomer (1) represented by formula (1) in the figure, in the presence of a compound (D) represented by formula (D) in the figure, a polymerization initiator (I) having a 10-hour half-life temperature of 140°C or lower, and a reducing agent (R). A composition comprises a polymer (P) having a structural unit (i) derived from a monomer (1) represented by formula (1), and a compound (D) represented by formula (D), where the content of the compound (D) is greater than 0 mass% and less than or equal to 1 mass% relative to the total of 100 mass% of the polymer (P) and the compound (D). (In the formula, R1 to R4 are independently H or a monovalent organic group, and j represents an integer from 1 to 5.)SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a method for producing a polymer, a composition, and a molded article. [Background technology]

[0002] Modifiers are sometimes used in components for electronic devices, electrical devices, office automation equipment, automobile components, building components, and other resins to improve their impact strength. As a modifier, for example, Patent Document 1 discloses an acrylic rubber graft copolymer obtained by emulsion polymerization of a vinyl monomer such as methyl methacrylate in the presence of an acrylic rubber component. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-319482 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the polymerization method described in Patent Document 1 may result in the obtained polymer having a yellowish tinge. If a yellowish polymer is used, the obtained molded article may also have a yellowish tinge, resulting in a decrease in designability. An object of the present invention is to provide a method for producing a polymer that can produce a polymer with reduced yellowing. Another object of the present invention is to provide a novel composition and a molded article containing the composition. [Means for solving the problem]

[0005] The present invention has the following aspects. [1] A method for producing a polymer, comprising polymerizing a radically polymerizable monomer component (M) containing a monomer (1) represented by the following formula (1) in the presence of a compound (D) represented by the following formula (D), a polymerization initiator (I) having a 10-hour half-life temperature of 140°C or less, and a reducing agent (R):

[0006] [ka]

[0007] In formula (D), R 1 ~R 4 are each independently a hydrogen atom or a monovalent organic group.

[0008] [ka]

[0009] In formula (1), j is an integer of 1 to 5.

[0010] [2] The method for producing a polymer according to [1] above, wherein the radical polymerizable monomer component (M) further contains an alkyl(meth)acrylate. [3] The method for producing a polymer according to [1] or [2] above, wherein the monomer (1) contains myrcene. [4] The method for producing a polymer according to any one of the above [1] to [3], wherein the content of the monomer (1) is 50 to 95 mass % based on the total mass of the radically polymerizable monomer component (M). [5] A polymer (P) having a structural unit (i) derived from a monomer (1) represented by the following formula (1), and a compound (D) represented by the following formula (D): A composition in which the content of the compound (D) is more than 0% by mass and 1% by mass or less when the total of the polymer (P) and the compound (D) is 100% by mass.

[0011] [ka]

[0012] In formula (1), j is an integer of 1 to 5.

[0013] [ka]

[0014] In formula (D), R 1 ~R 4 are each independently a hydrogen atom or a monovalent organic group.

[0015] [6] The composition according to [5], wherein the monomer (1) comprises myrcene. [7] The polymer (P) is a copolymer having a polymer chain (A) and a polymer chain (B), the polymer chain (A) has at least the structural unit (i), The composition according to [5] or [6] above, wherein the polymer chain (B) has a different composition from the polymer chain (A). [8] The composition according to [7], wherein the polymer chain (A) further has a structural unit (v-1) derived from one or more compounds selected from limonene, camphene, and β-pinene. [9] The composition according to [7] or [8] above, wherein the content of the structural unit (i) is 30 to 99.9 mass % relative to the total mass of the polymer chain (A).

[10] The composition according to any one of the above [7] to [9], wherein the polymer chain (B) has a structural unit (ii) derived from an alkyl(meth)acrylate.

[11] The composition according to any one of [7] to

[10] above, wherein the proportion of the polymer chain (A) is 50 to 90 mass % when the total of the polymer chain (A) and the polymer chain (B) is 100 mass %.

[12] The composition according to any one of [7] to

[11] above, wherein the copolymer is a graft copolymer in which a graft chain is introduced into the polymer chain (A), and the graft chain is the polymer chain (B).

[13] A molded article comprising the composition according to any one of [5] to

[12] above. [Effects of the Invention]

[0016] According to the present invention, it is possible to provide a method for producing a polymer that can produce a polymer with reduced yellowing. Furthermore, according to the present invention, it is possible to provide a novel composition and a molded article containing the composition. DETAILED DESCRIPTION OF THE INVENTION

[0017] 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. Alkyl acrylate and alkyl methacrylate are collectively referred to as "alkyl (meth)acrylate." 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.

[0018] [Polymer manufacturing method] The method for producing a polymer according to the first aspect of the present invention is a method for obtaining a polymer (P) by polymerizing a radically polymerizable monomer component (M) in the presence of a compound (D), a polymerization initiator (I), and a reducing agent (R) shown below.

[0019] <Compound (D)> The compound (D) is a compound represented by the following formula (D).

[0020] [ka]

[0021] In formula (D), R 1 ~R 4 are each independently a hydrogen atom or a monovalent organic group. R 1 ~R 4Among these, it is preferable that at least one is a hydrogen atom and at least one is a monovalent organic group.

[0022] Examples of the monovalent organic group include a vinyl group, a hydrocarbon group having one or more double bonds (excluding a vinyl group), an alkyl group, etc. Among these, a vinyl group, a hydrocarbon group having one or more double bonds, and an alkyl group are preferred. The hydrocarbon group having one or more double bonds preferably has 4 to 18 carbon atoms, more preferably 6 to 12 carbon atoms, and even more preferably 6 to 10 carbon atoms. The number of double bonds contained in the hydrocarbon group having one or more double bonds is preferably 1 to 4, more preferably 1 to 3, and even more preferably 1 or 2. Examples of hydrocarbon groups having one or more double bonds include -CH2-CH2-C(=CH2)-CH=CH2, -CH2-CH2-CH=C(CH3)2, and -C(=CH2)-CH2-CH2-CH=C(CH3)2. The alkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms, and even more preferably 1 or 2 carbon atoms.

[0023] Examples of the compound (D) include a dimer of the monomer (1) described below. Specific examples include a compound (D-1) represented by the following formula (D-1), a compound (D-2) represented by the following formula (D-2), a compound (D-3) represented by the following formula (D-3), a compound (D-4) represented by the following formula (D-4), a compound (D-5) represented by the following formula (D-5), and a compound (D-6) represented by the following formula (D-6).

[0024] [ka]

[0025] <Polymerization initiator (I)> The 10-hour half-life temperature of the polymerization initiator (I) used in the present embodiment is 140° C. or lower, preferably 50 to 140° C., more preferably 70 to 135° C., and even more preferably 100 to 130° C. When the 10-hour half-life temperature is equal to or lower than the above upper limit, dimerization of the monomer (1), which will be described later, can be suppressed in the polymerization of the radically polymerizable monomer component (M), and yellowing of the polymer can be suppressed. The 10-hour half-life temperature is the temperature required for the polymerization initiator to decompose due to heat and for the concentration of the polymerization initiator to decrease to half of its initial value after 10 hours. Specifically, when a benzene solution of a polymerization initiator with a concentration of 0.2 mol / L is prepared and the polymerization initiator is thermally decomposed in this benzene solution, the 10-hour half-life temperature is the temperature at which the half-life of the polymerization initiator becomes 10 hours. Note that the 10-hour half-life temperature is a value specific to the composition of the polymerization initiator, and when a commercially available polymerization initiator is used, if a catalog value is available, the catalog value may be used as the 10-hour half-life temperature of the polymerization initiator.

[0026] The polymerization initiator (I) is not particularly limited as long as it has a 10-hour half-life temperature of 140° C. or less, and any known polymerization initiator can be used. Examples of such initiators include organic peroxides such as hydroperoxides, ketone peroxides, diacyl peroxides, dialkyl peroxides, peroxyketals, alkyl peresters, and percarbonates. These polymerization initiators may be used alone or in combination of two or more.

[0027] Examples of the polymerization initiator (I) having a 10-hour half-life temperature of 140°C or less include hydroperoxides such as p-menthane hydroperoxide (128°C), cumyl peroxy neodecanoate (36.5°C), dicumyl peroxide (116.4°C), and 1,1,3,3-tetramethylbutyl hydroperoxide (135°C); ketone peroxides such as methyl ethyl ketone peroxide (105°C), methyl isobutyl ketone peroxide (88°C), and cyclohexanone peroxide (90°C); benzoyl peroxide; diacyl peroxides such as dioctyl peroxide (72°C), dicumyl peroxide (116°C); dialkyl peroxides such as succinic acid peroxide (66°C); 1,1-di(t-butylperoxy)-3,3,5-trimethylcyclohexane (90°C), 1,1-di(t-hexylperoxy)-3,3,5-trimethylcyclohexane (87°C), 1,1-di(t-butylperoxy)cyclohexane (93°C), 2,2-bis(4,4-di-t-butylperoxycyclohexyl)propane (92°C), 1,1-bis(t-butylperoxy)cyclohexane (93°C), peroxyketals such as tert-hexylperoxy-2-ethylhexanate (69°C), 1,1,3,3-tetramethylbutylperoxy-3,5,5-trimethylhexanate (86°C), t-amylperoxy-2-ethylhexanate (70°C), t-butylperoxy-2-ethylhexanate (74°C), t-amylperoxy-3,5,5-trimethylhexanate (95°C), t-butylperoxy-3,5,5-trimethylhexanate (97°C), t-butylperoxyisopropylperoxy butyrate (78°C), di-t-butylperoxyhexahydroterephthalate (83°C), t-butylperoxymaleic acid (96°C), t-butylperoxybenzoate (105°C); percarbonates such as t-butylperoxyisopropyl carbonate (97°C), 1,1,3,3-tetramethylbutylperoxyisopropyl carbonate (88°C), t-amylperoxyisopropyl carbonate (96°C), t-hexylperoxyisopropyl carbonate (95°C).Among these, hydroperoxides are preferred, and p-menthane hydroperoxide is more preferred. The temperature in parentheses after the compound is the 10-hour half-life temperature.

[0028] <Reducing Agent (R)> The reducing agent (R) is not particularly limited, but is preferably one that acts as a redox initiator when used in combination with the polymerization initiator (I). Examples of such reducing agents include sodium formaldehyde sulfoxylate, L-ascorbic acid, fructose, dextrose, sorbose, inositol, ferrous sulfate, disodium ethylenediaminetetraacetate, and tetrasodium ethylenediaminetetraacetate. These reducing agents may be used alone or in combination of two or more. In particular, a combination of ferrous sulfate, disodium ethylenediaminetetraacetate, and sodium formaldehyde sulfoxylate is particularly preferred.

[0029] <Radical polymerizable monomer component (M)> The radically polymerizable monomer component (M) (hereinafter also referred to as "monomer component (M)") contains a monomer (1) (hereinafter also referred to as "monomer (1)") represented by the following formula (1): The monomer component (M) preferably further contains, in addition to the monomer (1), an alkyl (meth)acrylate (hereinafter also referred to as "monomer (2)"). The monomer component (M) may further contain a monofunctional monomer (3) (hereinafter also referred to as "monomer (3)") other than the monomer (1) and the monomer (2), a polyfunctional monomer (4) (hereinafter also referred to as "monomer (4)"), etc.

[0030] The monomer (1) is a monomer represented by the following formula (1).

[0031] [ka]

[0032] In formula (1), j is an integer of 1 to 5, preferably an integer of 1 or 2, and more preferably 1. Monomer (1) is myrcene when j=1 and farnesene when j=2. The monomer (1) is preferably a plant-derived monomer. When the monomer (1) is plant-derived, the resulting polymer (P) contributes to a carbon-recycling society. In particular, myrcene is preferred as the monomer (1). These monomers (1) may be used alone or in combination of two or more. That is, the polymer (P) obtained by the method for producing a polymer according to the first aspect of the present invention may be a homopolymer, a copolymer, or a graft copolymer.

[0033] Examples of the monomer (2) include alkyl (meth)acrylates such as methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, glycidyl acrylate, octyl acrylate, phenyl acrylate, 1-naphthyl acrylate, 2-naphthyl acrylate, p-diphenyl acrylate, o-diphenyl acrylate, o-chlorophenyl acrylate, 4-methoxyphenyl acrylate, 4-chlorophenyl acrylate, 2,4,6-trichlorophenyl acrylate, 4-tert-butylphenyl acrylate, methoxytripropylene glycol acrylate, 4-hydroxybutyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, propyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, n-lauryl methacrylate, and stearyl methacrylate. Of these, methyl methacrylate, n-butyl acrylate, and 2-ethylhexyl acrylate are more preferred. These monomers (2) may be used alone or in combination of two or more.

[0034] Examples of the monomer (3) include acrylate monomers other than alkyl (meth)acrylates, such as glycidyl acrylate, phenyl acrylate, 1-naphthyl acrylate, 2-naphthyl acrylate, p-diphenyl acrylate, o-diphenyl acrylate, o-chlorophenyl acrylate, 4-methoxyphenyl acrylate, 4-chlorophenyl acrylate, 2,4,trichlorophenyl acrylate, and 4-tert-butylphenyl acrylate; and aromatic vinyl monomers, such as styrene, α-methylstyrene, and vinyl toluene. Monomers include diene monomers such as 1,3-butadiene and isoprene; vinyl cyanide monomers such as acrylonitrile and methacrylonitrile; vinyl ether monomers such as vinyl methyl ether and vinyl ethyl ether; carboxylic acid vinyl monomers such as vinyl acetate and vinyl butyrate; olefin monomers such as ethylene, propylene, and isobutylene; halogenated vinyl monomers such as vinyl chloride and vinylidene chloride; and maleimide monomers such as maleimide, N-phenylmaleimide, N-cyclohexylmaleimide, and N-methylmaleimide. These monomers (3) may be used alone or in combination of two or more.

[0035] Examples of the monomer (4) include crosslinking agents such as ethylene glycol dimethacrylate, propylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, 1,4-butylene glycol dimethacrylate, and divinylbenzene; and grafting agents such as allyl acrylate, allyl methacrylate, triallyl cyanurate, and triallyl isocyanurate. Of these, allyl acrylate and allyl methacrylate are preferred. These monomers (4) may be used alone or in combination of two or more.

[0036] The proportions of the monomers (1), (2), (3) and (4) in 100% by mass of the monomer component (M) are not particularly limited and may be appropriately adjusted according to the target polymer, for example as follows: The content of the monomer (1) relative to the total mass of the monomer component (M) is preferably from 50 to 100 mass%, more preferably from 50 to 95 mass%, and even more preferably from 50 to 80 mass%. The content of the monomer (2) relative to the total mass of the monomer component (M) is preferably from 0 to 50 mass%, more preferably from 5 to 50 mass%, and even more preferably from 20 to 50 mass%. The content of the monomer (3) relative to the total mass of the monomer component (M) is preferably from 0 to 10 mass%, more preferably from 0 to 5 mass%, and even more preferably from 0 to 3 mass%. The content of the monomer (4) relative to the total mass of the monomer component (M) is preferably from 0 to 5 mass%, more preferably from 0 to 3 mass%, and even more preferably from 0 to 2 mass%.

[0037] <Polymerization of monomer component (M)> (First embodiment) When producing the polymer (P) which is a homopolymer or a copolymer (excluding graft copolymers), the polymer (P) is obtained by polymerizing the monomer component (M) in the presence of the above-mentioned compound (D), polymerization initiator (I) and reducing agent (R). The monomer component (M), the compound (D), the polymerization initiator (I) and the reducing agent (R) may be added to the reaction system all at once or continuously.

[0038] The polymerization temperature when polymerizing the monomer component (M) is preferably 25 to 90°C, more preferably 35 to 80°C, and even more preferably 50 to 75°C. When the polymerization temperature is equal to or higher than the above lower limit, the polymerization time can be shortened. When the polymerization temperature is equal to or lower than the above upper limit, dimerization of the monomer (1) during polymerization can be further suppressed, and the by-production of a new dimer compound can be further suppressed. The polymerization time for polymerizing the monomer component (M) is preferably within 10 hours, more preferably 1 to 8 hours, and even more preferably 1 to 5 hours. When the polymerization time is equal to or less than the upper limit, dimerization of the monomer (1) during polymerization can be further suppressed, and the by-production of a new dimer compound can be further suppressed.

[0039] When polymerizing the monomer component (M), the non-conjugated olefin (O) may be present, i.e., the monomer component (M) may be polymerized in the presence of the compound (D), the non-conjugated olefin (O), the polymerization initiator (I), and the reducing agent (R). Examples of the non-conjugated olefin (O) include cyclic monoterpenes, α-olefins, etc. Among these, cyclic monoterpenes are preferred from the viewpoint of suppressing heat generation during polymerization. These non-conjugated olefins may be used alone or in combination of two or more.

[0040] Examples of cyclic monoterpenes include limonene, camphene, α-pinene, β-pinene, sabinene, etc. Among these, from the viewpoint of further suppressing heat generation during polymerization, limonene, camphene, and β-pinene are preferred, and limonene is more preferred. These cyclic monoterpenes may be used alone or in combination of two or more.

[0041] The proportion of the compound (D) is preferably 0.1 to 1 part by mass, more preferably 0.2 to 0.7 parts by mass, and even more preferably 0.2 to 0.5 parts by mass, relative to 100 parts by mass of the monomer component (M). When the proportion of the compound (D) is equal to or greater than the lower limit, heat generation during polymerization can be suppressed. When the proportion of the compound (D) is equal to or less than the upper limit, coloration of the resulting polymer (P) can be suppressed. The ratio of compound (D) here refers to the total amount of compound (D) used throughout the polymerization reaction of monomer component (M). That is, it refers to the total amount of compound (D) used relative to 100 parts by mass of the total amount (total added amount) of monomer component (M) used until the polymerization reaction is completed. The same applies to the ratios of polymerization initiator (I) and reducing agent (R) described below.

[0042] The proportion of the polymerization initiator (I) is preferably 0.1 to 10 parts by mass, more preferably 0.1 to 5 parts by mass, and even more preferably 0.5 to 3 parts by mass, relative to 100 parts by mass of the monomer component (M). When the proportion of the polymerization initiator (I) is equal to or greater than the above lower limit, the polymerization conversion rate of the monomer component (M) can be increased. When the proportion of the polymerization initiator (I) is equal to or less than the above upper limit, the residue of the polymerization initiator (I) after polymerization can be reduced.

[0043] The proportion of the reducing agent (R) is preferably 0.01 to 2 parts by mass, more preferably 0.01 to 1 part by mass, and even more preferably 0.01 to 0.7 parts by mass, relative to 100 parts by mass of the monomer component (M). When the proportion of the reducing agent (R) is equal to or greater than the above lower limit, the polymerization conversion rate of the monomer component (M) can be increased. When the proportion of the reducing agent (R) is equal to or less than the above upper limit, coloration of the polymer (P) can be suppressed.

[0044] The proportion of the non-conjugated olefin (O) is preferably 0.1 to 50 parts by mass, more preferably 1 to 30 parts by mass, even more preferably 1 to 25 parts by mass, even more preferably 1 to 20 parts by mass, particularly preferably 1 to 15 parts by mass, and most preferably 1 to 10 parts by mass, relative to 100 parts by mass of the monomer component (M). When the proportion of the non-conjugated olefin (O) is equal to or greater than the lower limit, heat generation during polymerization can be suppressed. When the proportion of the non-conjugated olefin (O) is equal to or less than the upper limit, polymerization proceeds easily, and the polymerization conversion rate of the monomer component (M) can be maintained at a good level, which tends to result in good powder properties of the resulting polymer (P). The proportion of non-conjugated olefin (O) here refers to the total amount of non-conjugated olefin (O) used throughout the polymerization reaction of the monomer component (M), i.e., the total amount of non-conjugated olefin (O) used relative to 100 parts by mass of the total amount (total added amount) of monomer component (M) used until the polymerization reaction is completed.

[0045] The polymer (P) has a structural unit derived from the monomer component (M), and by polymerizing the monomer component (M) in the presence of the compound (D), a portion of the compound (D) may be copolymerized with the monomer (1). That is, the polymer (P) may further have a structural unit derived from the compound (D) in addition to the structural unit derived from the monomer component (M). Furthermore, when the monomer component (M) is polymerized in the coexistence of a non-conjugated olefin (O), a portion of the non-conjugated olefin (O) may polymerize with the monomer component (M). That is, the polymer (P) may further have a structural unit derived from the non-conjugated olefin (O) in addition to a structural unit derived from the monomer component (M). The polymer (P) has a structural unit (i) (hereinafter also referred to as "structural unit (i)") derived from the monomer (1). In addition to the structural unit (i), the polymer (P) may further have at least one of a structural unit (vi) (hereinafter also referred to as "structural unit (vi)") derived from the compound (D) and a structural unit (v) (hereinafter also referred to as "structural unit (v)") derived from the non-conjugated olefin (O).

[0046] The method for polymerizing the monomer component (M) is not particularly limited, as long as the monomer component (M) is polymerized in the presence of the compound (D), the polymerization initiator (I), and the reducing agent (R). Examples of the method include a method for polymerizing the monomer component (M) using an emulsion polymerization method, a suspension polymerization method, a solution polymerization method, etc.

[0047] Among these, emulsion polymerization is preferred from the viewpoint of ease of controlling the particle size of the resulting polymer (P). Hereinafter, a method for producing polymer (P) by polymerizing monomer component (M) by emulsion polymerization will be described in detail. As the emulsion polymerization method, commonly known methods such as batch addition polymerization of monomers, continuous addition polymerization, and multi-stage polymerization can be used. When the emulsion polymerization method is used, a latex in which the polymer (P) is dispersed in water (hereinafter also referred to as "polymer (P) latex") can be obtained. The polymer (P) latex contains unreacted compound (D). That is, the polymer (P) latex can be said to be a composition containing the polymer (P), the compound (D), and water. When the polymerization is carried out in the coexistence of a non-conjugated olefin (O), the polymer (P) latex contains unreacted non-conjugated olefin (O) in addition to the compound (D). That is, the polymer (P) latex can be said to be a composition containing the polymer (P), the compound (D), the non-conjugated olefin (O), and water.

[0048] The emulsifier used in emulsion polymerization may be an emulsifier having an ionic hydrophilic moiety and a nonionic hydrophilic moiety in the same molecule, or may be a nonionic emulsifier. Examples of emulsifiers having an ionic hydrophilic moiety and a nonionic hydrophilic moiety in the same molecule include carboxylic acid-based emulsifiers, phosphoric acid-based emulsifiers, and sulfonic acid-based emulsifiers. These emulsifiers may be used alone or in combination of two or more.

[0049] Examples of carboxylic acid emulsifiers include caprylic acid, pelargonic acid, capric acid, lauric acid, myristic acid, palmitic acid, margaric acid, stearic acid, arachidic acid, behenic acid, lignoceric acid, cerotic acid, montanic acid, myristoleic acid, palmitoleic acid, oleic acid, elaidic acid, vaccenic acid, ricinoleic acid, gadoleic acid, eicosenoic acid, erucic acid, nervonic acid, linoleic acid, eicosadienoic acid, docosadienoic acid, linolenic acid, pinolenic acid, and eleostearic acid. Examples of metal salts include metal salts of saturated or unsaturated fatty acids having an alkyl group having 8 to 28 carbon atoms, such as sarcosine, mead acid, eicosatrienoic acid, stearidonic acid, arachidonic acid, eicosatetraenoic acid, adrenic acid, bosseopentaenoic acid, eicosapentaenoic acid, osbondo acid, sardine acid, tetracosapentaenoic acid, docosahexaenoic acid, and nisinic acid; metal salts of oligocarboxylic acid compounds such as alkenylsuccinic acid; and metal salts of sarcosine derivatives such as N-lauroylsarcosine and N-cocoylsarcosine. These carboxylic acid emulsifiers may be used alone or in combination of two or more.

[0050] Examples of the phosphoric acid emulsifier include polyoxyethylene phenyl ether phosphate, polyoxyethylene alkyl phenyl ether phosphate, polyoxyethylene alkyl ether phosphate, and alkyl phosphate. These phosphoric acid-based emulsifiers may be used alone or in combination of two or more.

[0051] Examples of sulfonic acid emulsifiers include polyoxyalkylene alkyl ether sulfonates, alkylbenzene sulfonates, α-sulfofatty acid methyl ester salts, and α-olefin sulfonates. These sulfonic acid emulsifiers may be used alone or in combination of two or more.

[0052] Examples of nonionic emulsifiers include polyoxyalkylene alkyl ethers, polyoxyethylene alkylene alkyl ethers, polyoxyethylene distyrenated phenyl ethers, polyoxyethylene tribenzyl phenyl ethers, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, and polyoxyethylene fatty acid esters. These nonionic emulsifiers may be used alone or in combination of two or more.

[0053] The amount of emulsifier used is preferably 0.1 to 20 parts by mass per 100 parts by mass of the total of the monomer component (M), the compound (D), and the non-conjugated olefin (O). When the amount of emulsifier used is equal to or greater than the lower limit, emulsion stability is likely to be improved. When the amount of emulsifier used is equal to or less than the upper limit, coagulation of the polymer (P) latex is facilitated, and the polymer (P) is easily recovered. The amount of emulsifier used here refers to the total amount of emulsifier used throughout the polymerization reaction of the monomer component (M). That is, it refers to the total amount of emulsifier used per 100 parts by mass of the total amount (total added amount) of the monomer component (M), compound (D), and non-conjugated olefin (O) used until the polymerization reaction is completed. The same applies to the amount of water used, which will be described later.

[0054] In emulsion polymerization, water is usually used as the solvent. The amount of water used is preferably 100 to 700 parts by mass, more preferably 400 to 600 parts by mass, per 100 parts by mass of the total of the monomer component (M), the compound (D) and the non-conjugated olefin (O).

[0055] As described above, the polymer (P) is obtained as a latex dispersed in water. The method for recovering the polymer (P) from the polymer (P) latex is not particularly limited, but for example, the polymer (P) can be obtained as a powder by drying the polymer (P) latex by a spray drying method or a freeze drying method, or by coagulation. Among these, drying or coagulation by a spray drying method is preferred. Drying the polymer (P) latex by spray drying tends to improve the dispersibility of the polymer (P) powder when it is added to, for example, a resin material. By coagulating the polymer (P) latex, impurities such as the emulsifier used in the emulsion polymerization can be easily removed, and therefore a powder of the polymer (P) with high purity can be easily obtained.

[0056] In the case of drying by the spray drying method, for example, the polymer (P) latex is sprayed onto fine droplets and then dried by applying hot air to them. Examples of the device for generating droplets include a rotating disk type, a pressure nozzle type, and a two-fluid nozzle type. The hot air temperature is preferably 100 to 200° C. If the hot air temperature is equal to or higher than the lower limit, the polymer (P) latex can be easily dried sufficiently. If the hot air temperature is equal to or lower than the upper limit, thermal decomposition of the powder can be easily suppressed.

[0057] When coagulation is performed, for example, the polymer (P) latex is introduced into hot water in which a coagulant has been dissolved, and the polymer (P) is separated and purified by salting out, and the coagulated, wet product is dehydrated and dried. Examples of the coagulant 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. The coagulant may be used alone or in combination of two or more kinds, but when used in combination, it is necessary to select a combination that does not form a water-insoluble salt. For example, when calcium acetate is used in combination with sulfuric acid or its sodium salt, a water-insoluble calcium salt may be formed, and it is difficult to separate this calcium salt from the polymer (P) powder.

[0058] The volume average particle size (Dv) of the polymer (P) thus obtained is preferably from 50 to 1000 nm, more preferably from 70 to 500 nm. The volume average particle size (Dv) of the polymer (P) can be controlled by adding an enlargement agent to the polymer (P) latex. Various thickening agents can be used, including, for example, acid group-containing copolymers and oxyacid salts. Examples of acid group-containing copolymers include copolymers having acrylic acid, methacrylic acid, itaconic acid, or the like as constituent elements. Examples of oxyacid salts include alkali metal salts or alkaline earth metal salts of oxyacids, or at least one oxyacid salt selected from zinc, nickel, and aluminum salts. Specific examples of oxyacid salts include potassium salts, sodium salts, magnesium salts, calcium salts, nickel salts, and aluminum salts of oxyacids such as sulfuric acid, nitric acid, and phosphoric acid. In this specification, the volume-based particle size distribution is measured using a laser diffraction / scattering particle size distribution analyzer, and the median diameter is taken as the volume-average particle size (Dv).

[0059] The polymer (P) thus obtained is a homopolymer or a copolymer, but the method for producing a polymer according to the first aspect of the present invention may be, for example, a method for producing a graft copolymer in which the polymer chain (A) is a rubber portion (core portion) and the polymer chain (B) is a graft portion (shell portion). In this specification, the graft portion is also referred to as a "graft chain." An example of a method for producing the polymer (P), which is a graft copolymer, will be described below.

[0060] Second Embodiment The method for producing polymer (P) of the second embodiment involves polymerizing a radically polymerizable monomer component (Ma) (hereinafter also referred to as "monomer component (Ma)") that constitutes polymer chain (A) to produce polymer chain (A), and then polymerizing a radically polymerizable monomer component (Mb) (hereinafter also referred to as "monomer component (Mb)") that constitutes polymer chain (B) in the presence of the resulting polymer chain (A) to produce polymer (P). The polymer (P) thus obtained is a graft copolymer in which a graft chain is introduced into the polymer chain (A), and the graft chain is polymer chain (B). In the following description, the polymerization of the monomer component (Ma) is also referred to as the "first polymerization reaction," and the polymerization of the monomer component (Mb) is also referred to as the "second polymerization reaction."

[0061] In the second embodiment, the first polymerization reaction and the second polymerization reaction are preferably carried out in the presence of a polymerization initiator (I) and a reducing agent (R). At least one of the first polymerization reaction and the second polymerization reaction is carried out in the presence of compound (D). It is preferable to carry out at least the first polymerization reaction in the presence of compound (D), and it is more preferable to carry out both the first polymerization reaction and the second polymerization reaction in the presence of compound (D).

[0062] In addition, when at least one of the first polymerization reaction and the second polymerization reaction is carried out, a non-conjugated olefin (O) may be coexistent. When a non-conjugated olefin (O) is coexistent, it is preferable to carry out at least the first polymerization reaction in the presence of the non-conjugated olefin (O), and it is more preferable to carry out both the first polymerization reaction and the second polymerization reaction in the presence of the non-conjugated olefin (O). Specific aspects of the second embodiment include α and β shown below.

[0063] α: A polymer chain (A) is produced by polymerizing a monomer component (Ma) that constitutes the polymer chain (A) in the presence of a compound (D), a non-conjugated olefin (O), a polymerization initiator (I), and a reducing agent (R), and a polymer (P) that is a graft copolymer is produced by polymerizing a monomer component (Mb) that constitutes the polymer chain (B) in the presence of the obtained polymer chain (A) and in the presence of the compound (D), a non-conjugated olefin (O), a polymerization initiator (I), and a reducing agent (R). β: A polymer chain (A) is produced by polymerizing a monomer component (Ma) that constitutes the polymer chain (A) in the presence of a compound (D), a non-conjugated olefin (O), a polymerization initiator (I), and a reducing agent (R). The resulting polymer chain (A) is then polymerized with a monomer component (Mb) that constitutes the polymer chain (B) in the presence of the polymerization initiator (I) and a reducing agent (R) but in the absence of the compound (D) and the non-conjugated olefin (O), to produce a polymer (P) that is a graft copolymer.

[0064] The monomer component (Ma) preferably contains the monomer (1). The monomer component (Ma) may further contain, in addition to the monomer (1), one or more monomers selected from the group consisting of the monomer (2), the monomer (3) and the monomer (4). That is, the polymer chain (A) preferably has a structural unit (structural unit (i)) derived from the monomer (1). In addition to the structural unit (i), the polymer chain (A) may further have one or more structural units selected from the group consisting of a structural unit (ii) derived from the monomer (2) (hereinafter also referred to as "structural unit (ii)"), a structural unit (iii) derived from the monomer (3) (hereinafter also referred to as "structural unit (iii)"), and a structural unit (iv) derived from the monomer (4) (hereinafter also referred to as "structural unit (iv)").

[0065] The proportion of the monomer (1) for obtaining the polymer chain (A) is preferably 30 to 99.9 mass%, more preferably 50 to 99.9 mass%, even more preferably 80 to 99.9 mass%, and particularly preferably 90 to 99 mass%, based on the total mass of the monomer component (Ma). The proportion of the monomer (2) for obtaining the polymer chain (A) is preferably 0 to 10 mass %, more preferably 0 to 5 mass %, based on the total mass of the monomer component (Ma). The proportion of the monomer (3) for obtaining the polymer chain (A) is preferably 0 to 10 mass %, more preferably 0 to 5 mass %, based on the total mass of the monomer components (Ma). The proportion of the monomer (4) for obtaining the polymer chain (A) is preferably 0.1 to 10 mass %, more preferably 0.1 to 5 mass %, based on the total mass of the monomer component (Ma).

[0066] The monomer component (Mb) preferably has a different composition from the monomer component (Ma). It is preferred that the monomer component (Mb) is substantially free of the monomer (1). The monomer component (Mb) preferably contains the monomer (2). The monomer component (Mb) may further contain at least one of the monomer (3) and the monomer (4) in addition to the monomer (2). That is, the polymer chain (B) preferably has the structural unit (ii). Furthermore, the polymer chain (B) may further have at least one of the structural unit (iii) and the structural unit (iv) in addition to the structural unit (ii). Furthermore, the polymer chain (B) preferably does not substantially have the structural unit (i). Here, "substantially free of structural unit (i)" means that the content of structural unit (i) in polymer chain (B) is 0 to 1 mass% relative to 100 mass% of all structural units constituting polymer chain (B). The content of structural unit (i) in polymer chain (B) is preferably 0 to 0.8 mass%, more preferably 0 to 0.5 mass%, even more preferably 0 to 0.1 mass%, and particularly preferably 0 to 0.01 mass%, relative to 100 mass% of all structural units constituting polymer chain (B).

[0067] The total proportion of the monomer (1) for obtaining the polymer chain (B) is preferably 0 to 1 mass %, more preferably 0 to 0.8 mass %, even more preferably 0 to 0.5 mass %, particularly preferably 0 to 0.1 mass %, and most preferably 0 to 0.01 mass %, based on the total mass of the monomer component (Mb). The total proportion of the monomers (2) for obtaining the molecular chain (B) is preferably 99 to 100 mass %, more preferably 99.9 to 100 mass %, based on the total mass of the monomer components (Mb). The proportion of the monomer (3) for obtaining the molecular chain (B) is preferably 0 to 1 mass %, more preferably 0 to 0.01 mass %, based on the total mass of the monomer component (Mb). The proportion of the monomer (4) for obtaining the molecular chain (B) is preferably 0 to 1 mass %, more preferably 0 to 0.01 mass %, based on the total mass of the monomer component (Mb).

[0068] The polymer chain (A) is obtained by polymerizing the monomer component (Ma). Examples of the method for polymerizing the monomer component (Ma) include methods in which the monomer component (Ma) is polymerized using an emulsion polymerization method, a suspension polymerization method, a solution polymerization method, etc. Among these, the emulsion polymerization method is preferred from the viewpoint of facilitating control of the particle size of the resulting polymer chain (A). The polymerization method, polymerization temperature, polymerization time, and emulsifier used in emulsion polymerization may be those exemplified above in the description of the first embodiment.

[0069] The amount of the emulsifier used is preferably 0.1 to 20 parts by mass per 100 parts by mass of the total of the monomer component (Ma), the compound (D) and the non-conjugated olefin (O). The amount of water used is preferably 600 to 1400 parts by mass, more preferably 800 to 1200 parts by mass, per 100 parts by mass of the total of the monomer component (Ma), the compound (D) and the non-conjugated olefin (O). The amount of emulsifier used here refers to the total amount of emulsifier used throughout the first polymerization reaction. That is, it refers to the total amount of emulsifier used per 100 parts by mass of the total amount (total added amount) of the monomer component (Ma), compound (D), and non-conjugated olefin (O) used until the first polymerization reaction is completed. The same applies to the amount of water used.

[0070] When the first polymerization reaction is carried out in the presence of compound (D), the proportion of compound (D) is preferably 0.1 to 1 part by mass, more preferably 0.2 to 0.7 parts by mass, and even more preferably 0.2 to 0.5 parts by mass, relative to 100 parts by mass of monomer component (Ma). When the proportion of compound (D) is equal to or greater than the above lower limit, heat generation during polymerization can be suppressed. When the proportion of compound (D) is equal to or less than the above upper limit, coloration of the resulting polymer (P) can be suppressed. The ratio of compound (D) here refers to the total amount of compound (D) used throughout the first polymerization reaction. That is, it refers to the total amount of compound (D) used relative to 100 parts by mass of the total amount (total added amount) of monomer component (Ma) used until the first polymerization reaction is completed. The same applies to the ratios of polymerization initiator (I) and reducing agent (R) described below.

[0071] The proportion of the polymerization initiator (I) is preferably 0.1 to 10 parts by mass, more preferably 0.1 to 5 parts by mass, and even more preferably 0.5 to 3 parts by mass, relative to 100 parts by mass of the monomer component (Ma). When the proportion of the polymerization initiator (I) is equal to or greater than the above lower limit, the polymerization conversion rate of the monomer component (Ma) can be increased. When the proportion of the polymerization initiator (I) is equal to or less than the above upper limit, the residue of the polymerization initiator (I) after polymerization can be reduced.

[0072] The proportion of the reducing agent (R) is preferably 0.01 to 2 parts by mass, more preferably 0.01 to 1 part by mass, and even more preferably 0.01 to 0.7 parts by mass, relative to 100 parts by mass of the monomer component (Ma). When the proportion of the reducing agent (R) is equal to or greater than the above lower limit, the polymerization conversion rate of the monomer component (Ma) can be increased. When the proportion of the reducing agent (R) is equal to or less than the above upper limit, coloration of the polymer (P) can be suppressed.

[0073] Furthermore, when the first polymerization reaction is carried out in the presence of a non-conjugated olefin (O), the amount of the non-conjugated olefin (O) is preferably 0.1 to 50 parts by mass, more preferably 1 to 30 parts by mass, even more preferably 1 to 25 parts by mass, even more preferably 1 to 20 parts by mass, particularly preferably 1 to 15 parts by mass, and most preferably 1 to 10 parts by mass, relative to 100 parts by mass of the monomer component (Ma). When the proportion of the non-conjugated olefin (O) is equal to or greater than the above lower limit, heat generation during polymerization can be suppressed. When the proportion of the non-conjugated olefin (O) is equal to or less than the above upper limit, polymerization can proceed easily, and the polymerization conversion rate of the monomer component (Ma) can be maintained at a good level. The proportion of the non-conjugated olefin (O) here refers to the total amount of the non-conjugated olefin (O) used throughout the first polymerization reaction, i.e., the total amount of the non-conjugated olefin (O) used relative to 100 parts by mass of the total amount (total added amount) of the monomer component (Ma) used until the first polymerization reaction is completed.

[0074] When the second polymerization reaction is carried out in the presence of a non-conjugated olefin (O), the proportion of the non-conjugated olefin (O) is preferably 0.1 to 50 parts by mass, more preferably 1 to 30 parts by mass, even more preferably 1 to 25 parts by mass, even more preferably 1 to 20 parts by mass, particularly preferably 1 to 15 parts by mass, and most preferably 1 to 10 parts by mass, relative to 100 parts by mass of the monomer component (Mb). When the proportion of the non-conjugated olefin (O) is equal to or greater than the lower limit, heat generation during polymerization can be suppressed. When the proportion of the non-conjugated olefin (O) is equal to or less than the upper limit, polymerization proceeds easily, and a good polymerization conversion rate of the monomer component (Mb) can be maintained. The proportion of the non-conjugated olefin (O) here refers to the total amount of the non-conjugated olefin (O) used throughout the second polymerization reaction, i.e., the total amount of the non-conjugated olefin (O) used relative to 100 parts by mass of the total amount (total added amount) of the monomer component (Mb) used until the second polymerization reaction is completed.

[0075] As described above, when polymerization is carried out in the presence of a non-conjugated olefin (O), either one of the first and second polymerization reactions may be carried out in the presence of the non-conjugated olefin (O). However, it is preferable to carry out both the first and second polymerization reactions in the presence of the non-conjugated olefin (O). In this case, the ratio of the non-conjugated olefin (O) to each radically polymerizable monomer component in each polymerization reaction is preferably within the above-mentioned range. However, the ratio of the non-conjugated olefin (O) to the total amount (total added amount) of the monomer components (Ma) used until the completion of the first polymerization reaction and the total amount (total added amount) of the monomer components (Mb) used until the completion of the second polymerization reaction is preferably 0.1 to 50 parts by mass, more preferably 1 to 30 parts by mass, even more preferably 1 to 25 parts by mass, even more preferably 1 to 20 parts by mass, particularly preferably 1 to 15 parts by mass, and most preferably 1 to 10 parts by mass. When the proportion of the non-conjugated olefin (O) is equal to or greater than the above lower limit, heat generation during polymerization can be suppressed.

[0076] The polymer chain (A) has a structural unit derived from the monomer component (Ma). When the first polymerization reaction is carried out in the presence of the compound (D), a portion of the compound (D) may copolymerize with the monomer component (Ma) as the monomer component (Ma) polymerizes. That is, when the first polymerization reaction is carried out in the presence of the compound (D), the polymer chain (A) may further have a structural unit derived from the compound (D) (structural unit (vi)) in addition to the structural unit derived from the monomer component (Ma). Furthermore, when the first polymerization reaction is carried out in the presence of a non-conjugated olefin (O), a portion of the non-conjugated olefin (O) may polymerize with the monomer component (Ma) during polymerization of the monomer component (Ma). That is, when the first polymerization reaction is carried out in the presence of a non-conjugated olefin (O), the polymer chain (A) may further have a structural unit (structural unit (v)) derived from the non-conjugated olefin (O) in addition to the structural unit derived from the monomer component (Ma). For example, when the monomer component (Ma) contains the monomer (1), the polymer chain (A) contains the structural unit (i). In addition to the structural unit (i), the polymer chain (A) may further contain at least one of the structural unit (vi) and the structural unit (v).

[0077] The volume average particle size (Dv) of the polymer chains (A) is preferably from 50 to 1000 nm, more preferably from 70 to 500 nm.

[0078] The polymer chain (A) is obtained as a latex dispersed in water (hereinafter also referred to as "polymer chain (A) latex"). The second polymerization reaction, that is, polymerization of the monomer component (Mb), can be carried out in the polymer chain (A) latex. By polymerizing the monomer component (Mb) in the polymer chain (A) latex, it is possible to produce a graft copolymer (polymer (P) (hereinafter also referred to simply as "graft copolymer") having the polymer chain (A) as the rubber portion (core portion) and the polymer chain (B) as the graft portion (shell portion). Specifically, the monomer component (Mb) is added to the polymer chain (A) latex and impregnated, and then the monomer component (Mb) is polymerized by the action of a polymerization initiator (I). When the first polymerization reaction is carried out in the presence of a polymerization initiator (I), the polymerization initiator (I) used in the production of the polymer chain (A) may be used as the polymerization initiator (I) used in polymerizing the monomer component (Mb), or may be added separately. Methods for adding the polymerization initiator (I) separately include adding the entire amount all at once to the polymer chain (A) latex, or adding it dropwise at a constant rate to the polymer chain (A) latex. The same applies to the reducing agent.

[0079] The amount of monomer component (Mb) added is not particularly limited, but is preferably 50 to 90 mass% of the total amount of monomer component (Ma) added and the total amount of monomer component (Mb) added, with the total amount being 100 mass%. The amount of monomer component (Ma) added is preferably 55 to 80 mass%, more preferably 60 to 75 mass%. If the total amount of monomer component (Ma) added is equal to or greater than the lower limit, excellent low-temperature impact properties are likely to be obtained when the resulting graft copolymer is added to, for example, a resin material. If the total amount of monomer component (Ma) added is equal to or less than the upper limit, the resulting graft copolymer exhibits good dispersibility when added to, for example, a resin material. The total amount of monomer component (Ma) used here refers to the total amount (total added amount) of monomer component (Ma) used until the first polymerization reaction is completed. The total amount of monomer component (Mb) used refers to the total amount (total added amount) of monomer component (Mb) used until the second polymerization reaction is completed.

[0080] The method for polymerizing the monomer component (Mb) is not particularly limited, and examples thereof include methods in which the monomer component (Mb) is polymerized using an emulsion polymerization method, a suspension polymerization method, a solution polymerization method, etc. Among these, the emulsion polymerization method is preferred from the viewpoint of easy control of the particle size of the resulting graft copolymer. The polymerization method, polymerization temperature, polymerization time, and emulsifier used in emulsion polymerization are the same as those exemplified above. The emulsifier used in producing the polymer chain (A) may be used as it is as the emulsifier used in polymerizing the monomer component (Mb), or may be added separately.

[0081] When a polymerization initiator (I) is separately added in the polymerization of the monomer component (Mb), the amount of the polymerization initiator (I) used is preferably 0.1 to 10 parts by mass, more preferably 0.1 to 5 parts by mass, and even more preferably 0.1 to 2 parts by mass, per 100 parts by mass of the monomer component (Mb). The amount of polymerization initiator (I) used here refers to the total amount of polymerization initiator (I) used throughout the second polymerization reaction. That is, it refers to the total amount of polymerization initiator (I) used relative to 100 parts by mass of the total amount (total added amount) of monomer component (Mb) used until the second polymerization reaction is completed. The same applies to the amount of emulsifier used, which will be described later.

[0082] When an emulsifier is separately added in the polymerization of the monomer component (Mb), the amount of the emulsifier used is preferably 0.1 to 20 parts by mass per 100 parts by mass of the monomer component (Mb), the compound (D), and the non-conjugated olefin (O).

[0083] When the first polymerization reaction is carried out in the presence of the compound (D), the polymer chain (A) latex obtained in the first polymerization reaction contains unreacted compound (D) in addition to the polymer chain (A). Polymerizing the monomer component (Mb) in the polymer chain (A) latex containing unreacted compound (D) means that the second polymerization reaction is also carried out in the presence of the compound (D).

[0084] Furthermore, when the first polymerization reaction is carried out in the presence of a non-conjugated olefin (O), the polymer chain (A) latex obtained in the first polymerization reaction may contain unreacted non-conjugated olefin (O) in addition to the polymer chain (A). Polymerizing the monomer component (Mb) in the polymer chain (A) latex containing unreacted non-conjugated olefin (O) means that the second polymerization reaction is also carried out in the presence of a non-conjugated olefin (O).

[0085] When the first polymerization reaction is carried out in the presence of a non-conjugated olefin (O) and the second polymerization reaction is carried out in the absence of a non-conjugated olefin (O), the polymer chain (A) is first recovered from the polymer chain (A) latex obtained in the first polymerization reaction, water is added to the recovered polymer chain (A) to reconstitute it into a latex state, and then a monomer component (Mb) and the like are added to carry out the second polymerization reaction. The same applies to the case where the first polymerization reaction is carried out in the presence of a compound (D) and the second polymerization reaction is carried out in the absence of a compound (D). The method for recovering the polymer chains (A) from the polymer chain (A) latex is not particularly limited. For example, the polymer chains (A) can be obtained as a powder by drying the polymer chain (A) latex using a spray drying method or a freeze drying method, or by coagulation. Among these, drying or coagulation using a spray drying method is preferred. Furthermore, when coagulation is performed, impurities such as the emulsifier used in the emulsion polymerization can be easily removed, making it easy to obtain a powder of the polymer chains (A) with high purity. The conditions for the spray drying method and the coagulation method are the same as those previously described in the first embodiment.

[0086] When the first polymerization reaction is carried out in the absence of the non-conjugated olefin (O) and the second polymerization reaction is carried out in the presence of the non-conjugated olefin (O), the non-conjugated olefin (O), the monomer component (Mb), etc. may be added to the polymer chain (A) latex obtained in the first polymerization reaction, and then the second polymerization reaction may be carried out. When only the second polymerization reaction is carried out in the presence of a non-conjugated olefin (O), the proportion of the non-conjugated olefin (O) is preferably 0.1 to 50 parts by mass, more preferably 1 to 30 parts by mass, even more preferably 1 to 25 parts by mass, even more preferably 1 to 20 parts by mass, particularly preferably 1 to 15 parts by mass, and most preferably 1 to 10 parts by mass, per 100 parts by mass of the monomer component (Mb). When the proportion of the non-conjugated olefin (O) is equal to or greater than the lower limit, heat generation during polymerization can be suppressed. When the proportion of the non-conjugated olefin (O) is equal to or less than the upper limit, polymerization proceeds easily, and a good polymerization conversion rate of the monomer component (Mb) can be maintained. The proportion of the non-conjugated olefin (O) here refers to the total amount of the non-conjugated olefin (O) used throughout the second polymerization reaction, i.e., the total amount of the non-conjugated olefin (O) used relative to 100 parts by mass of the total amount (total added amount) of the monomer component (Mb) used until the second polymerization reaction is completed.

[0087] The polymer chain (B) has a structural unit derived from the monomer component (Mb). When the second polymerization reaction is carried out in the presence of the compound (D), a portion of the compound (D) may copolymerize with the monomer component (Mb) during polymerization of the monomer component (Mb). That is, when the second polymerization reaction is carried out in the presence of the compound (D), the polymer chain (B) may further have a structural unit derived from the compound (D) (structural unit (vi)) in addition to the structural unit derived from the monomer component (Mb). Furthermore, when the second polymerization reaction is carried out in the presence of a non-conjugated olefin (O), a portion of the non-conjugated olefin (O) may polymerize with the monomer component (Mb) during polymerization of the monomer component (Mb). That is, when the second polymerization reaction is carried out in the presence of a non-conjugated olefin (O), the polymer chain (B) may further have a structural unit (structural unit (v)) derived from the non-conjugated olefin (O) in addition to the structural unit derived from the monomer component (Mb). For example, when the monomer component (Mb) contains the monomer (2), the polymer chain (B) contains the structural unit (ii). In addition to the structural unit (ii), the polymer chain (B) may further contain at least one of the structural unit (vi) and the structural unit (v).

[0088] The polymer (P), which is a graft copolymer, is obtained as a latex dispersed in water (hereinafter also referred to as "graft copolymer latex"). The graft copolymer latex obtained by emulsion polymerization may be blended with additives such as an antioxidant, if necessary. The graft copolymer latex may be produced by blending the antioxidant in advance and then carrying out emulsion polymerization. Examples of the antioxidant include phenol-based antioxidants, thioether-based antioxidants, phosphite-based antioxidants, etc. These antioxidants may be used alone or in combination of two or more. The antioxidant may be blended as a powder or tablet, or may be blended in a state of being dispersed in water. However, a method of blending the antioxidant in a state of being dispersed in water into the graft copolymer latex is preferred. This allows the antioxidant to be added more uniformly, making it easier to suppress oxidative degradation of the graft copolymer. When an antioxidant is added to the graft copolymer latex, the amount of the antioxidant used is preferably 0.0001 to 10 parts by mass, more preferably 0.001 to 6 parts by mass, and even more preferably 0.01 to 3 parts by mass, per 100 parts by mass of the total of the monomer component (Ma) and the monomer component (Mb). The amount of antioxidant used here refers to the total amount of antioxidant used relative to 100 parts by mass of the total amount (total added amount) of the monomer component (Ma) used until the first polymerization reaction and the second polymerization reaction are completed, and the total amount (total added amount) of the monomer component (Mb).

[0089] The method for recovering the graft copolymer from the graft copolymer latex is not particularly limited. For example, the graft copolymer can be obtained as a powder by drying the graft copolymer latex using a spray drying method or a freeze drying method, or by coagulation. Among these, drying or coagulation using a spray drying method is preferred. When drying is performed using a spray drying method, the dispersibility of the graft copolymer powder when added to a resin material is likely to be improved. Furthermore, when coagulation is performed, impurities such as the emulsifier used in the emulsion polymerization can be easily removed, making it easy to obtain a highly pure graft copolymer powder. The conditions for the spray drying method and the coagulation method are the same as those previously described in the first embodiment.

[0090] The volume average particle size (Dv) of the thus obtained graft copolymer is preferably from 60 to 1100 nm, more preferably from 80 to 600 nm. The number average particle size (Dn) of the graft copolymer is preferably from 30 to 600 nm, more preferably from 50 to 400 nm. In this specification, the number-based particle size distribution is measured using a laser diffraction / scattering particle size distribution analyzer, and the median diameter is taken as the number-average particle diameter (Dn).

[0091] <Action and effect> According to the method for producing a polymer of the first aspect of the present invention, a polymer is produced by polymerizing the monomer component (M) in the presence of the compound (D), the polymerization initiator (I), and the reducing agent (R), so that a polymer (P) with suppressed yellowing can be obtained. The reason for this is not clear, but is thought to be as follows. When the monomer (1) contained in the monomer component (M) is polymerized, depending on the polymerization temperature and polymerization time, a Diels-Alder reaction may occur as a side reaction, causing the monomer (1) to dimerize and produce a dimer of the monomer (1) as a by-product. The more the amount of the dimer of the monomer (1) produced, the more likely the polymer (P) will become yellowish. When the monomer (1) is polymerized with a specific compound (D) and a polymerization initiator (I) in the presence of a reducing agent, the monomer (1) is copolymerized with a portion of the compound (D), which reduces the occurrence of side reactions and the generation of new dimers of the monomer (1). As a result, it is believed that a polymer (P) with reduced yellowing can be obtained.

[0092] <Polymer> The polymer (P) obtained by the present invention has a structural unit (structural unit (i)) derived from the monomer (1). The polymer (P) preferably has a structural unit (structural unit (ii)) derived from the monomer (2). The polymer (P) may have at least one of a structural unit derived from the monomer (3) (structural unit (iii)) and a structural unit derived from the monomer (4) (structural unit (iv)). The polymer (P) may have a structural unit (structural unit (vi)) derived from the compound (D). The polymer (P) may have a structural unit (structural unit (v)) derived from a non-conjugated olefin (O). When the polymer (P) has a structural unit (v), it preferably has a structural unit (v-1) (hereinafter also referred to as "structural unit (v-1)") derived from one or more compounds selected from limonene, camphene, and β-pinene as the non-conjugated olefin (O).

[0093] A preferred embodiment of the polymer (P) is a copolymer having the above-mentioned polymer chain (A) and polymer chain (B). In particular, a graft copolymer in which the polymer chain (A) is the rubber portion (core portion) and the polymer chain (B) is the graft portion (shell portion) is preferred. That is, the graft copolymer is a graft copolymer in which a graft chain is introduced into the polymer chain (A), and the graft chain is the polymer chain (B).

[0094] The proportion of the polymer chain (A) is preferably 50 to 90% by mass, more preferably 55 to 80% by mass, and even more preferably 60 to 75% by mass, when the total of the polymer chain (A) and the polymer chain (B) is 100% by mass. If the proportion of the polymer chain (A) is equal to or greater than the above lower limit, excellent low-temperature impact properties are likely to be obtained when the graft copolymer () is added to, for example, a resin material. If the proportion of the polymer chain (A) is equal to or less than the above upper limit, good dispersibility is achieved when the graft copolymer () is added to, for example, a resin material.

[0095] The polymer chain (A) preferably has the structural unit (i). The polymer chain (A) may further include, in addition to the structural unit (i), one or more structural units selected from the structural units (ii) to (iv). In addition to the structural unit (i), the polymer chain (A) may further include at least one of the structural unit (v) and the structural unit (vi). In particular, when the polymer chain (A) includes the structural unit (v), it preferably also includes the structural unit (v-1).

[0096] The content of structural unit (i) in the polymer chain (A) is preferably 30 to 99.9 mass%, more preferably 50 to 99.9 mass%, even more preferably 80 to 99.9 mass%, and particularly preferably 90 to 99 mass%, relative to the total mass of the polymer chain (A1), i.e., 100 mass% of all structural units in the polymer chain (A). If the proportion of structural unit (i) is at or above the lower limit, low-temperature impact properties are likely to be obtained when the graft copolymer is added to, for example, a resin material. If the proportion of structural unit (i) is at or below the lower limit, optical properties are likely to be improved when the graft copolymer is added to, for example, a resin material. The content of the structural unit (ii) in the polymer chain (A) is preferably from 0 to 10 mass %, and more preferably from 0 to 5 mass %, relative to the total mass of the polymer chain (A). The content of the structural unit (iii) in the polymer chain (A) is preferably from 0 to 10 mass %, and more preferably from 0 to 5 mass %, relative to the total mass of the polymer chain (A). The content of the structural unit (iv) in the polymer chain (A) is preferably from 0.1 to 10 mass %, and more preferably from 0.1 to 5 mass %, relative to the total mass of the polymer chain (A). The content of the structural unit (v) in the polymer chain (A) is preferably from 0 to 10 mass %, and more preferably from 0 to 5 mass %, relative to the total mass of the polymer chain (A). The content of the structural unit (vi) in the polymer chain (A) is preferably from 0 to 5 mass %, and more preferably from 0 to 3 mass %, relative to the total mass of the polymer chain (A).

[0097] The polymer chain (B) preferably has a composition different from that of the polymer chain (A). It is preferable that the polymer chain (B) is substantially free of the structural unit (i). The polymer chain (B) preferably has the structural unit (ii). In addition to the structural unit (ii), the polymer chain (B) may further include at least one of the structural unit (iii) and the structural unit (iv). In addition to the structural unit (ii), the polymer chain (B1) may further include at least one of the structural unit (v) and the structural unit (vi).

[0098] The total proportion of the structural unit (i) in the polymer chain (B) is preferably 0 to 1 mass%, more preferably 0 to 0.8 mass%, even more preferably 0 to 0.5 mass%, particularly preferably 0 to 0.1 mass%, and most preferably 0 to 0.01 mass%, relative to the total mass of the polymer chain (B), i.e., 100 mass% of all structural units in the polymer chain (B). The content of the structural unit (ii) in the polymer chain (B) is preferably from 90 to 100 mass %, and more preferably from 95 to 100 mass %, based on the total mass of the polymer chain (B). The content of the structural unit (iii) in the polymer chain (B) is preferably from 0 to 10 mass %, and more preferably from 0 to 5 mass %, relative to the total mass of the polymer chain (B). The content of the structural unit (iv) in the polymer chain (B) is preferably from 0 to 5 mass %, and more preferably from 0 to 1 mass %, relative to the total mass of the polymer chain (B). The content of the structural unit (v) in the polymer chain (B) is preferably from 0 to 5 mass %, and more preferably from 0 to 1 mass %, based on the total mass of the polymer chain (B). The content of the structural unit (vi) in the polymer chain (B) is preferably from 0 to 5 mass %, and more preferably from 0 to 1 mass %, relative to the total mass of the polymer chain (B).

[0099] The polymer (P) obtained by the present invention is suitable as a resin additive, for example, a modifier for improving the impact strength of resins.

[0100] [Composition] The composition according to the second aspect of the present invention (hereinafter also referred to as "composition (X)") comprises a polymer (P) having a structural unit (structural unit (i)) derived from the monomer (1) represented by the formula (1) above, and a compound (D) represented by the formula (D) above. The monomer (1) and the compound (D) are the same as the monomer (1) and the compound (D) exemplified above in the description of the method for producing the polymer according to the first embodiment of the present invention, and therefore, a description thereof will be omitted. The monomer (1) preferably contains myrcene, that is, the polymer (P) preferably has a structural unit derived from myrcene.

[0101] The polymer (P) may be the polymer (P) obtained by the method for producing a polymer according to the first embodiment. A preferred embodiment of the polymer (P) is a copolymer having the above-mentioned polymer chain (A) and polymer chain (B). In particular, a graft copolymer in which the polymer chain (A) is a rubber portion (core portion) and the polymer chain (B) is a graft portion (shell portion) is preferred.

[0102] The content of polymer (P) is preferably 90% by mass or more and less than 100% by mass, more preferably 95 to 99.5% by mass, based on the total mass of the solid content of composition (X). Here, "solid content of composition (X)" refers to components other than volatile components contained in the composition, i.e., so-called pure components. "Volatile components" refer to components that volatilize at 150°C or higher. The content of compound (D) is more than 0% by mass and not more than 1% by mass, preferably more than 0% by mass and not more than 0.5% by mass, and more preferably more than 0% by mass and not more than 0.3% by mass, when the total of polymer (P) and compound (D) is taken as 100% by mass. When the content of compound (D) is not more than the above upper limit, yellowing of composition (X) can be sufficiently suppressed.

[0103] The composition (X) may further contain a non-conjugated olefin (O) in addition to the polymer (P) and the compound (D). The non-conjugated olefin (O) is the same as the non-conjugated olefin (O) exemplified above in the description of the method for producing the polymer according to the first embodiment of the present invention, and therefore a description thereof will be omitted. The non-conjugated olefin (O) preferably contains a cyclic monoterpene, and more preferably contains one or more selected from limonene, camphene, and β-pinene. The content of the non-conjugated olefin (O) is preferably from 0.01 to less than 10 parts by mass, more preferably from 0.01 to 5 parts by mass, when the total of the polymer (P) and the compound (D) is 100 parts by mass.

[0104] The composition (X) may further contain components other than the polymer (P), the compound (D) and the non-conjugated olefin (O) (hereinafter also referred to as "optional components"). Optional components include additives such as antioxidants, ultraviolet absorbers, dyes, and pigments.

[0105] Composition (X) can be prepared, for example, by polymerizing a radically polymerizable monomer component (M) (monomer component (M)) containing monomer (1) in the presence of compound (D), polymerization initiator (I), and reducing agent (R). This results in a composition containing polymer (P) having structural unit (i) and unreacted compound (D). During polymerization of monomer component (M), non-conjugated olefin (O) may be present. The compound (D), the polymerization initiator (I), the reducing agent (R), the radical polymerizable monomer component (M), and the non-conjugated olefin (O) are the same as the compound (D), the polymerization initiator (I), the reducing agent (R), the radical polymerizable monomer component (M), and the non-conjugated olefin (O) exemplified above in the description of the method for producing a polymer according to the first embodiment of the present invention, and therefore, description thereof will be omitted. Furthermore, the polymerization of the radical polymerizable monomer component (M) is the same as the polymerization of the radical polymerizable monomer component (M) in the method for producing a polymer according to the first embodiment of the present invention, and therefore a description thereof will be omitted. When the monomer component (M) is emulsion polymerized, the polymer (P) is obtained as a latex (polymer (P) latex). The polymer (P) latex contains the polymer (P) as well as the unreacted compound (D) and water.

[0106] The composition (X) of this embodiment is suitable as an adhesive, a primer, a paint, or a material for various molded articles in the form of an aqueous emulsion.

[0107] [Molded body] The molded article of the third aspect of the present invention (hereinafter also referred to as "molded article (Y)") contains the composition (X) of the second aspect of the present invention described above. In particular, it is preferable that the polymer (P) contained in the composition (X) is the above-mentioned graft copolymer. The molded article (Y) can be obtained by molding the composition (X) into a desired shape. Since the polymer (P) and the composition (X) can function as a resin modifier, the composition (X) may be added to a matrix resin for use. That is, a composition containing the composition (X) and a matrix resin (hereinafter also referred to as "resin composition (E)") may be molded into a desired shape to produce the molded product (Y). The matrix resin is not particularly limited, and examples thereof include polylactic acid, polycarbonate, polymethyl methacrylate, polystyrene, polyolefin, and polyester.

[0108] The molding method for the composition (X) and the resin composition (E) is not particularly limited, and known methods can be used, such as press molding, injection molding, gas-assisted injection molding, welding molding, extrusion molding, blow molding, film molding, blow molding, multi-layer molding, and melt spinning.

[0109] The use of the molded body (Y) is not particularly limited, but it can be suitably used as a component for electronic devices, electrical devices, office automation devices, automobile components, building components, and the like. [Example]

[0110] The present invention will be described in detail below with reference to examples and comparative examples, but the present invention is not limited to the following descriptions. In the following, "parts" means "parts by mass" unless otherwise specified.

[0111] [Measurement and Evaluation] <Identification and quantification of compound (D)> Measurement was performed using a gas chromatograph mass spectrometer (GC-MS), and the elution time of compound (D) was identified on the obtained chromatogram. Subsequently, measurement was performed using a chromatograph (GC-FID) equipped with a flame ionization detector (FID), and the area value of the peak of compound (D) appearing on the obtained chromatogram was determined. This area value was compared with a toluene calibration curve to quantify compound (D) in the sample in terms of toluene, and compound (D) contained in composition (X) was identified and its content was determined. The calibration curve was prepared using a standard solution prepared by adding a known amount of toluene to acetone. The sample preparation method used in the measurement and the measurement conditions for GC-MS and GC-FID are shown below.

[0112] (Sample preparation) 0.2 g of composition (X) was weighed, 4 mL of acetone was added thereto, and the mixture was allowed to stand for about 24 hours. After that, 1 mL of an acetone solution prepared by dissolving methyl salicylate in acetone to a concentration of 0.1% by mass was added as an internal standard substance to prepare a sample for measurement.

[0113] (GC-MS measurement conditions) ·Analytical equipment: Agilent product name "GC7890A" and Agilent product name "MS5977". Separation column: Restek RTX-1701 (length 30 m, inner diameter 0.25 mm, film thickness 1.0 μm). · Carrier gas: Helium. ·Inlet temperature: 260℃. Column temperature: After holding at 40°C for 10 minutes, the temperature was increased to 240°C at a rate of 10°C / min and held at 240°C for 10 minutes. Split mode: 50:1. Average linear velocity: 39.723 cm / s (constant flow mode). · Ionization method: EI. ·Ion source temperature: 230℃. MS scan range: 15-600 amu. Sample injection volume: 1.0 μL.

[0114] (GC-FID measurement conditions) -Analytical equipment: Agilent GC7890B. Separation column: Restek RTX-1701 (length 30 m, inner diameter 0.25 mm, film thickness 1.0 μm). · Carrier gas: Helium. ·Inlet temperature: 260℃. Column temperature: After holding at 40°C for 10 minutes, the temperature was increased to 240°C at a rate of 10°C / min and held at 240°C for 10 minutes. Split mode: 50:1. Average linear velocity: 39.723 cm / s (constant flow mode). ·Detector temperature: 260℃. Detector H2 flow rate: 30mL / min. Detector air flow rate: 400mL / min. Make-up He flow rate: 25 mL / min. Sample injection volume: 1.0 μL.

[0115] <Yellowness measurement> Composition (X) was formed into a film having a thickness of 0.3 mm. The yellowness of the obtained film was measured using a spectrophotometer (product name "SE-7700" manufactured by Nippon Denshoku Industries Co., Ltd.) in accordance with JIS K 7373: 2006. The smaller the value, the more suppressed the yellowing.

[0116] [Example 1] <Production of polymer chain (A)> As the monomer component (Ma), 54 parts of myrcene, which is the monomer (1), and 0.5 parts of allyl methacrylate (manufactured by Mitsubishi Chemical Corporation), which is the monomer (4), and 1.5 parts of limonene, 0.3 parts of camphene, and 0.2 parts of β-pinene, which are non-conjugated olefins (O), and 0.003 parts of the compound (D-1) represented by the formula (D-1), 0.004 parts of the compound (D-2) represented by the formula (D-2), 0.001 parts of the compound (D-3) represented by the formula (D-3), 0.003 parts of the compound (D-4) represented by the formula (D-5), 0.034 parts of the compound (D-5) represented by the formula (D-5), and 0.017 parts of the compound (D-6) represented by the formula (D-6), and 1.2 parts of sodium dodecylbenzenesulfonate were used as an emulsifier. These were added to 100 parts of deionized water and stirred at 15,000 rpm for 5 minutes to obtain a stable premixed emulsion.

[0117] The resulting premixed emulsion was placed in a polymerization apparatus equipped with a stirrer, a condenser, and a thermometer. The atmosphere inside the polymerization apparatus was thoroughly purged with nitrogen, and the temperature was then raised to 45°C. Next, 4 parts of p-menthane hydroperoxide (manufactured by NOF Corporation, trade name "Permenta H," 10-hour half-life temperature 128°C) as a polymerization initiator (I), and 0.002 parts of ferrous sulfate, 0.006 parts of disodium ethylenediaminetetraacetate, and 0.3 parts of sodium formaldehyde sulfoxylate as reducing agents were added to initiate polymerization. Stirring was continued for 300 minutes, yielding a polymer chain (A) latex.

[0118] <Production of Graft Copolymer> In the obtained polymer chain (A) latex, methyl methacrylate, which is the monomer (2), was polymerized as the monomer component (Mb) as follows to produce a graft copolymer. To 43.5 parts of methyl methacrylate (manufactured by Mitsubishi Chemical Corporation), 0.2 parts of p-menthane hydroperoxide (manufactured by NOF Corporation, trade name "Permenta H", 10-hour half-life temperature 128°C) was added as a polymerization initiator (I), and the resulting solution was continuously added dropwise to the polymer chain (A) latex over 60 minutes to carry out polymerization. Thereafter, the temperature inside the polymerization apparatus was raised to 70°C, and stirring was continued for 120 minutes to obtain a graft copolymer latex.

[0119] <Recovery of graft copolymer> To the obtained graft copolymer latex, 0.25 parts of n-octadecyl-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate (manufactured by BASF Japan Ltd., trade name "Irg1076") as a phenolic antioxidant and 0.75 parts of didodecyl 3,3'-thiodipropionate (manufactured by Bayer, trade name "DLDTP") as a thioether antioxidant were added. This was added to 460 parts of deionized water containing 5 parts by mass of calcium acetate to cause coagulation, followed by washing with water, dehydration, and drying to obtain the graft copolymer in powder form. The resulting graft copolymer was used as composition (X), and the structure of compound (D) contained in composition (X) was identified and the content of compound (D) was determined. Furthermore, composition (X) was used to prepare a test piece, and the yellowness index was measured. The results are shown in Table 1.

[0120] [Example 2] Composition (X) was produced in the same manner as in Example 1, except that in the production of polymer chain (A), the polymerization temperature was changed to 75°C, the amount of polymerization initiator (I) used was changed to 2 parts, and the amounts of compounds (D-1) to (D-6) used were changed as shown in Table 1. Various measurements and evaluations were carried out. The results are shown in Table 1.

[0121] [Comparative Example 1] A composition (X) was produced in the same manner as in Example 1, except that diisopropylbenzene hydroperoxide (manufactured by NOF Corporation, trade name "Percumyl P", 10-hour half-life temperature 145.1°C) was used as the polymerization initiator (I) and the amount of polymerization initiator (I) used in the production of polymer chain (A) was changed from 4 parts to 8 parts, and various measurements and evaluations were carried out. The results are shown in Table 1.

[0122] [Table 1]

[0123] The abbreviations in the table are as follows. Furthermore, the "proportion of non-conjugated olefin (O) relative to 100 parts by mass of monomer component (M)" refers to the proportion (parts by mass) of non-conjugated olefin (O) when the total of monomer component (Ma) and monomer component (Mb) is 100 parts by mass. Furthermore, the "proportion of compound (D) after polymerization" refers to the amount (% by mass) of each of compounds (D-1) to (D-6) when the total of the polymer and compound (D) contained in composition (X) is 100% by mass. Furthermore, the amount of polymerization initiator (I) used in the table refers to the amount (parts by mass) of polymerization initiator (I) used in producing polymer chain (A). · AMA: Allyl methacrylate. · MMA: Methyl methacrylate. Compound (D-1): A compound represented by the formula (D-1). Compound (D-2): A compound represented by the formula (D-2). Compound (D-3): A compound represented by the formula (D-3). Compound (D-4): A compound represented by the formula (D-4). Compound (D-5): A compound represented by the formula (D-5). Compound (D-6): A compound represented by the formula (D-6). · Permenta H: p-menthane hydroperoxide (manufactured by NOF Corporation, trade name "Permenta H", 10-hour half-life temperature 128°C). Percumyl P: Diisopropylbenzene hydroperoxide (manufactured by NOF Corporation, trade name "Percumyl P", 10-hour half-life temperature 145.1°C). · EDTA-2Na: Disodium ethylenediaminetetraacetic acid. ·SDBS: Sodium formaldehyde sulfoxylate.

[0124] As is clear from the results shown in Table 1, polymers with suppressed yellowing could be produced by polymerizing radically polymerizable monomer components in the presence of non-conjugated olefin (O).

Claims

1. A method for producing a polymer, comprising polymerizing a radically polymerizable monomer component (M) containing a monomer (1) represented by the following formula (1) in the presence of a compound (D) represented by the following formula (D), a polymerization initiator (I) having a 10-hour half-life temperature of 140°C or less, and a reducing agent (R): 【Chemical 1】 (In formula (D), R １ ~R ４ are each independently a hydrogen atom or a monovalent organic group. 【Chemistry 2】 (In formula (1), j is an integer of 1 to 5.)

2. The method for producing a polymer according to claim 1 , wherein the radically polymerizable monomer component (M) further comprises an alkyl (meth)acrylate.

3. The method for producing a polymer according to claim 1 or 2, wherein the monomer (1) comprises myrcene.

4. 3. The method for producing a polymer according to claim 1, wherein the content of the monomer (1) is 50 to 95 mass% based on the total mass of the radically polymerizable monomer component (M).

5. The polymer (P) includes a structural unit (i) derived from a monomer (1) represented by the following formula (1), and a compound (D) represented by the following formula (D): A composition in which the content of the compound (D) is more than 0% by mass and 1% by mass or less when the total of the polymer (P) and the compound (D) is 100% by mass. 【Chemistry 3】 (In formula (1), j is an integer of 1 to 5.) 【Chemistry 4】 (In formula (D), R １ ~R ４ are each independently a hydrogen atom or a monovalent organic group.

6. The composition of claim 5 , wherein the monomer (1) comprises myrcene.

7. the polymer (P) is a copolymer having a polymer chain (A) and a polymer chain (B), the polymer chain (A) has at least the structural unit (i), The composition of claim 5 , wherein the polymer chains (B) have a different composition than the polymer chains (A).

8. The composition according to claim 7, wherein the polymer chain (A) further has a structural unit (v-1) derived from one or more compounds selected from limonene, camphene, and β-pinene.

9. 8. The composition according to claim 7, wherein the content of the structural unit (i) is 30 to 99.9 mass% relative to the total mass of the polymer chain (A).

10. The composition according to claim 7 , wherein the polymer chain (B) has a structural unit (ii) derived from an alkyl (meth)acrylate.

11. 8. The composition according to claim 7, wherein the proportion of the polymer chain (A) is 50 to 90 mass % when the total of the polymer chain (A) and the polymer chain (B) is 100 mass %.

12. The composition according to claim 7 , wherein the copolymer is a graft copolymer in which a graft chain is introduced into the polymer chain (A), and the graft chain is the polymer chain (B).

13. A molded article comprising the composition according to any one of claims 5 to 12.

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