Vinyl polymer and its manufacturing method

Abstract

To provide a vinyl polymer having a polymerizable terminal double bond, a high molecular weight, and a high degree of branching, and a production method thereof.SOLUTION: Provided is a vinyl polymer having structures represented by formulas (1) and (2). In the formulas (1) and (2), when, relative to a total number of moles of hydrogen atoms and methyl groups contained in X1 to Xn, a ratio of the number of moles of hydrogen atoms is denoted by x, x is 85 mol% or more. When an absolute weight average molecular weight of the vinyl polymer, when measured by a light scattering detector, is denoted by Mwabs and a relative weight average molecular weight based on linear standard polymethyl methacrylate polymer, when measured by a differential refractometer, is denoted by Mw, Mabs / Mw is 1.5 or more.SELECTED DRAWING: None

Description

[Technical field]

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

[0002] Vinyl polymers obtained by polymerizing vinyl monomers are widely used in various applications including moldings and coatings. Various properties such as elastic modulus, mechanical strength, and durability are required for vinyl polymers, and the use of graft copolymers with different components in the main chain and side chains is effective in obtaining properties suitable for the application. As a raw material for the graft copolymer, a vinyl polymer having a polymerizable terminal double bond is used. The vinyl polymer having a polymerizable terminal double bond is advantageous in that the larger the molecular weight, the more excellent the graft copolymer can be synthesized in terms of elastic modulus, mechanical strength, durability, etc., but there is a problem that the melt viscosity and solution viscosity increase, and the handleability decreases. Here, the introduction of branches into the polymer is effective as a method for reducing the melt viscosity and solution viscosity. In other words, a vinyl polymer having a polymerizable terminal double bond, a high molecular weight, and a high degree of branching is required as a raw material for the graft copolymer. Vinyl polymers having polymerizable terminal double bonds can be synthesized by various methods. Examples of methods for synthesizing vinyl polymers having polymerizable terminal double bonds include a method of modifying a vinyl polymer with a compound having a double bond at the end of the vinyl polymer, a method of decomposing a vinyl polymer at high temperature, and a method using chain transfer polymerization. Among these, the method using chain transfer polymerization is widely used industrially because the target product can be obtained in one step. Examples of methods using chain transfer polymerization include a method using an addition fragmentation chain transfer agent (Non-Patent Document 1) and a method using catalytic chain transfer by cobalt (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2000-506189 [Non-patent literature]

[0004] [Non-Patent Document 1] Seiya Kobatake, Bunichiro Yamada, “Radical polymerization of a trimer of methyl acrylate as polymerizable α-substituted acrylate”, Molecular Chemistry and Physics, September 1997, Vol. 198, No. 9, pp. 2825-2837 Summary of the Invention [Problem to be solved by the invention]

[0005] Although the presence of a branched structure has been suggested for the vinyl polymers obtained by the production methods described in Patent Document 1 and Non-Patent Document 1, a high molecular weight has not been achieved. Thus, a vinyl polymer having a polymerizable terminal double bond, a high molecular weight, and a high degree of branching has not been achieved so far.

[0006] An object of the present invention is to provide a vinyl polymer which has a polymerizable terminal double bond, a high molecular weight and a high degree of branching, and a method for producing the same. [Means for solving the problem]

[0007] The present invention has the following configuration. [1] A vinyl polymer having a structure represented by the following formulas (1) and (2): In the following formulas (1) and (2), X 1 ~X n where x is the ratio of the number of moles of hydrogen atoms to the total number of moles of hydrogen atoms and methyl groups contained in the compound, x is 85 mol % or more; The vinyl polymer has an M / M ratio of 1.5 or more, where M is the absolute weight average molecular weight measured by a light scattering detector and M is the relative weight average molecular weight measured by a differential refractometer using a size exclusion chromatograph as a standard with respect to a linear standard poly(methyl methacrylate). [ka] In formula (1), R and R 1 ~R n are each independently a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, or a heterocyclic group; Z is a halogen atom or a group derived from a radical polymerization initiator; X 1 ~X n are each independently a hydrogen atom, a methyl group, or a structure represented by formula (2), and n is a natural number from 2 to 10,000. [ka] In formula (2), R and R 1 ~R n are each independently a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, or a heterocyclic group; Z is a halogen atom or a group derived from a radical polymerization initiator; X 1 ~X n R is each independently a hydrogen atom, a methyl group, or a structure represented by formula (2). n and X n In the above formula, n is a natural number from 2 to 10,000. R and R in formula (1) 1 ~R n and R and R in formula (2) 1 ~R n are independent of each other, and X in formula (1) 1 ~X n and X in Eq. (2) 1 ~X n are independent of each other. [2] The vinyl polymer according to [1], wherein the Mw is 20,000 or more. [3] The vinyl polymer according to [1] or [2], wherein the Mw is 50,000 or more. [4] A step (i) of preparing a polymerizable composition comprising a chain transfer agent (A) represented by the following formula (3), a vinyl monomer (B), and a polymerization initiator (C); (ii) polymerizing the polymerizable composition; The method for producing a vinyl polymer according to any one of [1] to [3], comprising: [ka] In formula (3), R' is a hydrogen atom, a halogen atom, -OC(O)R", -CONH2, -CN, -COOR" or an aryl group, and Y is -SR", a halogen atom, -SOR", -P(O)(OR")2, -SnR"3, -SiR"3 or -OOR". In R' and Y, R" is an alkyl group, a cycloalkyl group, an aryl group or a heterocyclic group. [5] The method for producing a vinyl polymer according to [4], wherein the conversion rate of the vinyl monomer (B) in the step (ii) is 85% or more. [6] The method for producing a vinyl polymer according to [4] or [5], wherein the content of the chain transfer agent (A) in the polymerizable composition is 0.1 to 20 mol per 100 mol of the vinyl monomer (B). Effect of the Invention

[0008] According to the present invention, there are provided a vinyl polymer which has a polymerizable terminal double bond, a high molecular weight and a high degree of branching, and a method for producing the same. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] In the present invention, a numerical range represented by "to" means a numerical range including the numerical values ​​before and after "to" as the lower limit and upper limit, respectively. In addition, "(meth)acrylic" means acrylic or methacrylic, "(meth)acrylate" means acrylate or methacrylate, and "(meth)acrylo" means acrylo or methacrylo.

[0010] [Vinyl polymer] The vinyl polymer of the present invention has structures represented by the following formulas (1) and (2).

[0011] [ka]

[0012] The meanings of the symbols in formula (1) are as follows: R and R 1 ~R n are each independently a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, or a heterocyclic group. Z is a halogen atom or a group derived from a radical polymerization initiator. X 1 ~X n are each independently a hydrogen atom, a methyl group, or a structure represented by formula (2), 1 ~X n At least one of them has a structure represented by formula (2). R n and X n In the above formula, n is a natural number from 2 to 10,000.

[0013] [ka]

[0014] The meanings of the symbols in formula (2) are as follows: R and R 1 ~R n are each independently a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, or a heterocyclic group; Z is a halogen atom or a group derived from a radical polymerization initiator; X 1 ~X n R is each independently a hydrogen atom, a methyl group, or a structure represented by formula (2). n and X n In the above formula, n is a natural number from 2 to 10,000.

[0015] R and R in formula (1) 1 ~R n and R in Eq. (2)1 ~R n are independent of each other, and X in formula (1) 1 ~X n and X in Eq. (2) 1 ~X n are independent of each other.

[0016] X in formula (1) 1 ~X n At least one of these has a structure represented by formula (2), and therefore the vinyl polymer of the present invention has a branched structure.

[0017] The vinyl polymer of the present invention has the structures represented by the formulas (1) and (2). 1 In H-NMR measurement, the compound has peaks with chemical shift values ​​of 5.5 to 5.6 ppm and 6.1 to 6.2 ppm, and 13 This can be confirmed by the presence of a peak with a chemical shift value of 38 to 41 ppm in C-NMR measurement. Where: 1 The peaks having chemical shift values ​​of 5.5 to 5.6 ppm and 6.1 to 6.2 ppm in H-NMR measurement indicate the presence of a terminal double bond in the vinyl polymer of the present invention represented by formula (1). 13 A peak having a chemical shift value of 38 to 41 ppm in C-NMR measurement means that the vinyl polymer of the present invention has a branched structure represented by formula (2).

[0018] In the vinyl polymer of the present invention, a terminal double bond is introduced as shown in formula (1). This terminal double bond has polymerizability and is useful because it allows the easy synthesis of a graft copolymer by copolymerizing it with a vinyl monomer.

[0019] The vinyl polymer of the present invention has structural units derived from (meth)acrylic acid or a (meth)acrylate compound, as represented by the formulas (1) and (2). Examples of the methacrylate-based compound include alkyl (meth)acrylates having 1 to 30 carbon atoms, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, glycidyl (meth)acrylate, methoxyethyl (meth)acrylate, ethoxyethyl (meth)acrylate, ethoxyethoxyethyl (meth)acrylate, polyethylene glycol (meth)acrylate and its alkyl ethers, benzyl (meth)acrylate, phenyl (meth)acrylate, 3-(triethoxysilyl)propyl (meth)acrylate, and 2-(dimethylamino)ethyl (meth)acrylate and its quaternary alkyl ammonium salts.

[0020] The vinyl polymer of the present invention may contain small amounts of other structural units within the range that does not impair the effects of the present invention. The other structural units are not particularly limited as long as they are structural units derived from monomers capable of radical polymerization. Examples of the monomer capable of radical polymerization include styrene-based monomers such as α-methylstyrene, vinyltoluene, and styrene; vinyl ether-based monomers such as methyl vinyl ether, ethyl vinyl ether, and isobutyl vinyl ether; fumaric acid, monoalkyl esters and dialkyl esters of fumaric acid, maleic acid, monoalkyl esters and dialkyl esters of maleic acid, itaconic acid, monoalkyl esters and dialkyl esters of itaconic acid, (meth)acrylonitrile, (meth)acrylamide, butadiene, isoprene, vinyl chloride, vinylidene chloride, vinyl acetate, vinyl ketone, vinylpyridine, and vinylcarbazole. These radically polymerizable monomers can be used alone or in combination of two or more.

[0021] In the vinyl polymer of the present invention, in the formulas (1) and (2), X 1 ~X nWhen the ratio of the number of moles of hydrogen atoms to the total number of moles of hydrogen atoms and methyl groups contained therein is x, x is 85 mol % or more, preferably 90 mol % or more, and more preferably 95 mol % or more. When x is 85 mol % or more, the vinyl polymer of the present invention has a high degree of branching. Note that x is a value calculated from the charge ratio of acrylic acid and acrylate compound in the vinyl monomer (B) as a raw material.

[0022] When the absolute weight average molecular weight of the vinyl polymer of the present invention measured by a light scattering detector is Mwabs and the relative weight average molecular weight based on a linear standard polymethyl methacrylate measured by a differential refractometer using a size exclusion chromatograph is Mwabs / Mw is 1.5 or more, preferably 2.0 or more. The Mwabs / Mw is an index of the branching degree of the vinyl polymer, and when the vinyl polymer does not have a branched structure, the Mwabs / Mw is 1.0, and when the vinyl polymer has many branched structures, the Mwabs / Mw is greater than 1.0. The higher the branching degree of the vinyl polymer, the greater the Mwabs / Mw. When the Mwabs / Mw is 1.5 or more, the degree of branching is high, and the melt viscosity and solution viscosity of the vinyl polymer of the present invention are reduced, resulting in excellent handleability.

[0023] In the vinyl polymer of the present invention, the Mwabs was determined by the following method. First, a vinyl polymer is measured under the following conditions using a gel permeation chromatograph (GPCmax manufactured by Viscotek) and a light scattering detector (TDA302 manufactured by Viscotek). Then, the absolute molecular weight and intrinsic viscosity at each elution position are calculated using analysis software (OmniSEC), and Mwabs is obtained. Columns: one TSKgel guardcolumn HXL-H (6.0 x 40 mm, Tosoh Corporation), two TSKgel Multipore HXL (7.8 x 300 mm, Tosoh Corporation), and one TSKgel G3000 HXL (7.8 x 300 mm, Tosoh Corporation) connected in series. Eluent: tetrahydrofuran. Column and detector temperature: 40°C. Flow rate: 1.0mL / min. Standards for instrument calibration: Polystyrene (Viscotek, molecular weight 105,000).

[0024] In the vinyl polymer of the present invention, the Mw was determined by the following method. First, size exclusion chromatography (HLC-8220 manufactured by Tosoh Corporation) is used to measure under the following conditions: Then, Mw is calculated using a calibration curve prepared using polymethyl methacrylate (Mp (peak molecular weight) = 141,500, 55,600, 11,100, and 1,590, four types) manufactured by Polymer Laboratories. Column: TSK GUARD COLUMN SUPER HH (4.6 x 35 mm, Tosoh Corporation) and two TSK-GEL SUPER HM-H (6.0 x 150 mm, Tosoh Corporation) connected in series. Eluent: tetrahydrofuran. Measurement temperature: 40℃. Flow rate: 0.6mL / min.

[0025] The Mw of the vinyl polymer of the present invention is not particularly limited, but is preferably at least 20,000, more preferably at least 50,000, even more preferably at least 100,000, even more preferably at least 300,000, and even more preferably at least 500,000. By using such a vinyl polymer as a raw material, a molded article and a coating film excellent in elastic modulus and mechanical strength can be obtained.

[0026] [Method of manufacturing vinyl polymer] The vinyl polymer of the present invention can be produced by a production method including the steps (i) and (ii) described below.

[0027] Step (i): A step of preparing a polymerizable composition containing a chain transfer agent (A) represented by the following formula (3), a vinyl monomer (B), and a polymerization initiator (C).

[0028] [ka]

[0029] The meanings of the symbols in formula (3) are as follows: R' is a hydrogen atom, a halogen atom, -OC(O)R", -CONH2, -CN, -COOR", or an aryl group. Y is -SR", a halogen atom, -SO2R", -P(O)(OR")2, -SnR"3, -SiR"3 or -OOR". In R' and Y, R'' is an alkyl group, a cycloalkyl group, an aryl group, or a heterocyclic group.

[0030] Step (ii): A step of polymerizing the polymerizable composition. Each step will be described in detail below.

[0031] <Process (i)> In step (i), a polymerizable composition is prepared containing a chain transfer agent (A) represented by the formula (3), a vinyl monomer (B), and a polymerization initiator (C). The polymerizable composition may contain a solvent and other additives as necessary. Each component will be described in detail below.

[0032] (Chain transfer agent (A)) The chain transfer agent (A) is a compound represented by the above formula (3). In the formula (3), R' is a hydrogen atom, a halogen atom, -OC(O)R", -CONH2, -CN, -COOR", or an aryl group.

[0033] Examples of the halogen atom in R' include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. The halogen atom is preferably a chlorine atom or a bromine atom. When R' is a halogen atom, it exhibits an appropriate chain transfer constant in step (ii).

[0034] The aryl group in R' is, for example, an aryl group having a carbon number of 6 to 18. Examples of the aryl group having a carbon number of 6 to 18 include a phenyl group, a benzyl group, and a naphthyl group. The aryl group may have a substituent. Examples of the substituent include an alkyl group, an aryl group, a carboxy group, an alkoxycarbonyl group, a carbamoyl group, a cyano group, a hydroxy group, an amino group, an amide group, a halogen atom, an allyl group, an epoxy group, an alkoxy group, and a group exhibiting hydrophilicity or ionicity. Examples of the group exhibiting hydrophilicity or ionicity include alkali salts of a carboxy group, alkali salts of a sulfoxy group, poly(alkylene oxide) groups such as a polyethylene oxide group and a polypropylene oxide group, and cationic substituents such as a quaternary ammonium base. In addition, in the formula (3), Y is -SR", a halogen atom, -SO2R", -P(O)(OR")2, -SnR"3, -SiR"3, or -OOR".

[0035] In the formula (3), Y is -SR", a halogen atom, -SO2R", -P(O)(OR")2, -SnR"3, -SiR"3 or -OOR".

[0036] Examples of the halogen atom in Y include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. The halogen atom is preferably a chlorine atom or a bromine atom. When Y is a halogen atom, it exhibits an appropriate chain transfer constant in step (ii).

[0037] In R' and Y, R'' is an alkyl group, a cycloalkyl group, an aryl group, or a heterocyclic group. Examples of the alkyl group for R" include a branched or linear alkyl group having 1 to 20 carbon atoms. Specific examples of the branched or linear alkyl group having 1 to 20 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, a t-butyl group, an i-butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, an undecyl group, a dodecyl group, a tridecyl group, a tetradecyl group, a pentadecyl group, a hexadecyl group, a heptadecyl group, an octadecyl group, a nonadecyl group, and an icosyl group.

[0038] Examples of the cycloalkyl group for R" include a cycloalkyl group having 3 to 20 carbon atoms. Specific examples of the cycloalkyl group having 3 to 20 carbon atoms include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, and an adamantyl group.

[0039] The aryl group in R'' is, for example, an aryl group having 6 to 18 carbon atoms. Specific examples of the aryl group having 6 to 18 carbon atoms include a phenyl group, a benzyl group, and a naphthyl group.

[0040] Examples of the heterocyclic group in R" include heterocyclic groups having 5 to 18 carbon atoms and containing an oxygen atom, a nitrogen atom, or a sulfur atom as a heteroatom. Specific examples of the heterocyclic group include a γ-lactone group, an ε-caprolactone group, and a morpholine group.

[0041] The alkyl group, cycloalkyl group, aryl group and heterocyclic group in R″ may have a substituent. Examples of the substituent include an alkyl group, an aryl group, a carboxy group, an alkoxycarbonyl group, a carbamoyl group, a cyano group, a hydroxy group, an amino group, an amide group, a halogen atom, an allyl group, an epoxy group, an alkoxy group, and a group exhibiting hydrophilicity or ionicity. Examples of the group exhibiting hydrophilicity or ionicity include alkali salts of a carboxy group, alkali salts of a sulfoxy group, poly(alkylene oxide) groups such as a polyethylene oxide group and a polypropylene oxide group, and cationic substituents such as a quaternary ammonium base.

[0042] R″ is preferably an alkyl group or a cycloalkyl group, and more preferably an alkyl group.

[0043] (Vinyl Monomer (B)) The vinyl monomer (B) is not particularly limited as long as it is a monomer having a vinyl group, but (meth)acrylic acid or the above-mentioned (meth)acrylate-based compounds are preferred. In addition to (meth)acrylic acid and the above-mentioned (meth)acrylate compound, the vinyl polymer of the present invention may contain a small amount of a radically polymerizable monomer within a range that does not impair the effects of the present invention. Examples of the monomer capable of radical polymerization include styrene-based monomers such as α-methylstyrene, vinyltoluene, and styrene; vinyl ether-based monomers such as methyl vinyl ether, ethyl vinyl ether, and isobutyl vinyl ether; fumaric acid, monoalkyl esters and dialkyl esters of fumaric acid, maleic acid, monoalkyl esters and dialkyl esters of maleic acid, itaconic acid, monoalkyl esters and dialkyl esters of itaconic acid, (meth)acrylonitrile, (meth)acrylamide, butadiene, isoprene, vinyl chloride, vinylidene chloride, vinyl acetate, vinyl ketone, vinylpyridine, and vinylcarbazole. These radically polymerizable monomers can be used alone or in combination of two or more.

[0044] The vinyl monomer (B) is preferably used so that the ratio (mol%) of the total number of moles of acrylic acid and acrylate-based compounds to the total number of moles of the vinyl monomer (B) is 85 mol% or more. This results in a vinyl polymer in which x is 85 mol% or more. The ratio (mol%) of the total number of moles of acrylic acid and acrylate-based compounds to the total number of moles of the vinyl monomer (B) is more preferably 90 mol% or more, and even more preferably 95 mol% or more.

[0045] (Polymerization initiator (C)) The polymerization initiator (C) is not particularly limited, and any conventionally known compound can be used, but a radical polymerization initiator is preferred. Examples of the radical polymerization initiator include an azo-based radical polymerization initiator and a peroxide-based radical polymerization initiator.

[0046] Specific examples of the azo radical polymerization initiator include 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile) and 2,2'-azobis(2,4-dimethyl-4-methoxyvaleronitrile). Specific examples of the peroxide-based radical polymerization initiator include 2,4-dichlorobenzoyl peroxide, t-butyl peroxypivalate, o-methylbenzoyl peroxide, bis-3,5,5-trimethylhexanoyl peroxide, octanoyl peroxide, t-butylperoxy-2-ethylhexanoate, cyclohexanone peroxide, benzoyl peroxide, methyl ethyl ketone peroxide, dicumyl peroxide, lauroyl peroxide, diisopropylbenzene hydroperoxide, t-butyl hydroperoxide, and di-t-butyl peroxide. The radical polymerization initiators may be used alone or in combination of two or more.

[0047] (solvent) The solvent is not particularly limited, but examples thereof include alcohol-based solvents (methanol, ethanol, etc.), aromatic hydrocarbon-based solvents (toluene, ethylbenzene, xylene, anisole, etc.), ketone-based solvents (acetone, methyl isobutyl ketone, methyl ethyl ketone, etc.), and ester-based solvents (butyl acetate, etc.). The solvents may be used alone or in combination of two or more.

[0048] (Composition of Polymerizable Composition) The content of the chain transfer agent (A) in the polymerizable composition is not particularly limited, but is preferably 0.001 to 50 mol per 100 mol of the vinyl monomer (B). When the content of the chain transfer agent (A) is 0.001 mol or more per 100 mol of the vinyl monomer (B), a branched structure can be appropriately introduced into the resulting vinyl polymer. When the content of the chain transfer agent (A) is 50 mol or less per 100 mol of the vinyl monomer (B), the properties of the vinyl polymer, such as elastic modulus, mechanical strength and durability, can be sufficiently obtained. The lower limit of the content of the chain transfer agent (A) is preferably 0.001 mol or more, more preferably 0.01 mol or more, and even more preferably 0.1 mol or more, per 100 mol of the vinyl monomer (B). The upper limit of the content of the chain transfer agent (A) is preferably 50 mol or less, more preferably 30 mol or less, and further preferably 20 mol or less, per 100 mol of the vinyl monomer (B). The content of the chain transfer agent (A) is preferably from 0.001 to 50 mol %, more preferably from 0.01 to 30 mol %, and further preferably from 0.1 to 20 mol %, based on 100 mol of the vinyl monomer (B).

[0049] The content of the polymerization initiator (C) in the polymerizable composition is not particularly limited, but is preferably 0.0001 to 20 mol per 100 mol of the vinyl monomer (B). When the content of the polymerization initiator (C) is within the range of 0.0001 to 20 mol per 100 mol of the vinyl monomer (B), an appropriate polymerization rate can be obtained in the step (ii) described below. The lower limit of the content of the polymerization initiator (C) is preferably 0.0001 mol or more, more preferably 0.01 mol or more, even more preferably 0.05 mol or more, still more preferably 0.10 mol or more, and even more preferably 0.15 mol or more, per 100 mol of the vinyl monomer (B). The upper limit of the content of the polymerization initiator (C) is preferably 20 mol or less, more preferably 5 mol or less, and further preferably 2 mol or less, per 100 mol of the vinyl monomer (B). The content of the polymerization initiator (C) is preferably 0.0001 to 20 mol, more preferably 0.01 to 20 mol, further preferably 0.05 to 20 mol, even more preferably 0.10 to 5 mol, and even more preferably 0.15 to 2 mol, relative to 100 mol of the vinyl monomer (B).

[0050] The content of the solvent in the polymerizable composition is not particularly limited, but is preferably 0 to 500 parts by mass relative to 100 parts by mass of the vinyl monomer (B). When the content of the solvent is 0 to 500 parts by mass relative to 100 parts by mass of the vinyl monomer (B), an appropriate polymerization rate can be obtained in the step (ii) described below, and the solution viscosity after the production of the vinyl polymer is reduced, resulting in excellent handleability. The lower limit of the content of the solvent is preferably 0 parts by mass or more, and more preferably 100 parts by mass or more, per 100 parts by mass of the vinyl monomer (B). The upper limit of the content of the solvent is preferably 500 parts by mass or less, and more preferably 300 parts by mass or less, per 100 parts by mass of the vinyl monomer (B).

[0051] (Other additives) Examples of other additives include pigments, ultraviolet absorbers, release agents, antifoaming agents, plasticizers, viscosity modifiers, etc. Known compounds can be used as these additives.

[0052] <Process (ii)> In step (ii), the polymerizable composition prepared in step (i) is polymerized. In step (ii), the radical generated from the polymerization initiator (C) is added to the vinyl monomer (B) to give a propagating radical. When the propagating radical is added to the chain transfer agent (A), a polymer having a structure represented by formula (1) is produced by an addition-fragmentation chain transfer mechanism. Here, in formula (1), X 1 When is a hydrogen atom, the terminal double bond exhibits copolymerizability with the vinyl monomer (B). Therefore, in the later stage of the step (ii), the polymer having the structure represented by formula (1) is introduced as a graft chain in the form of formula (2) to obtain the vinyl polymer according to the present invention.

[0053] The polymerization method for the polymerizable composition is not particularly limited, and for example, a conventionally known polymerization method such as bulk polymerization, solution polymerization, suspension polymerization, or emulsion polymerization can be used. The polymerization reaction may be carried out in the presence of air, but is preferably carried out in an inert gas atmosphere such as nitrogen or argon from the viewpoint of the efficiency of radical polymerization. Known techniques can be used to carry out the polymerization reaction in an inert gas atmosphere, and examples of such techniques include a technique of blowing an inert gas into the polymerizable composition and a technique of repeatedly freezing, degassing, and melting. The polymerization temperature is not particularly limited, but is preferably from 0 to 150°C, more preferably from 20 to 120°C, from the viewpoint of the polymerization rate. The polymerization time is not particularly limited, but is preferably 0.5 to 48 hours, and more preferably 4 to 48 hours.

[0054] The conversion rate of the vinyl monomer (B) in the step (ii) is preferably 85% or more, more preferably 90% or more, from the viewpoint of improving the molecular weight and the degree of branching of the resulting vinyl polymer. The conversion rate (%) of the vinyl monomer (B) was measured using a nuclear magnetic resonance apparatus (Avance, 300 MHz, manufactured by Bruker) and CDCl3 as the measurement solvent. 1It can be obtained from the measured value of H-NMR measurement. Specifically, the conversion rate (%) of the vinyl monomer (B) can be calculated as the ratio of the amount of the produced vinyl polymer to the sum of the amount of the remaining vinyl monomer (B) and the amount of the produced vinyl polymer, using the integrated value of the peak derived from the remaining vinyl monomer (B) and the integrated value of the peak derived from the produced vinyl polymer. EXAMPLES

[0055] The present invention will be described in more detail below with reference to examples. However, the present invention is not limited to the examples described below, and various modifications are possible without departing from the gist of the present invention.

[0056] [Raw materials] The abbreviations for the raw materials used in the examples and comparative examples are shown below. Chain transfer agent (A) MBMA: methyl 2-(bromomethyl)acrylate (Tokyo Chemical Industry Co., Ltd.) Vinyl monomer (B) nBA: n-butyl acrylate (Tokyo Chemical Industry Co., Ltd.) Polymerization initiator (C) AIBN: 2,2'-azobis(isobutyronitrile) (Tokyo Chemical Industry Co., Ltd.)

[0057] [Measurement and evaluation methods] <Absolute weight average molecular weight (Mwabs)> The Mwabs of the vinyl polymer was determined as follows. First, the vinyl polymer was measured under the following conditions using gel permeation chromatography (GPCmax manufactured by Viscotek) and a light scattering detector (TDA302 manufactured by Viscotek). Then, the absolute molecular weight and intrinsic viscosity at each elution position were calculated using the software (OmniSEC) attached to the device, and Mwabs was obtained. Columns: one TSKgel guardcolumn HXL-H (6.0 x 40 mm, Tosoh Corporation), two TSKgel Multipore HXL (7.8 x 300 mm, Tosoh Corporation), and one TSKgel G3000 HXL (7.8 x 300 mm, Tosoh Corporation) connected in series. Eluent: tetrahydrofuran. Column and detector temperature: 40°C. Flow rate: 1.0mL / min. Sample concentration: 2 mg / mL (polymer dissolved in tetrahydrofuran). Injection volume: 150μL. Standards for instrument calibration: polystyrene (Viscotek, molecular weight 105,000).

[0058] <Relative weight average molecular weight (Mw)> The Mw of the vinyl polymer was determined as follows. First, size exclusion chromatography (HLC-8220 manufactured by Tosoh Corporation) was used to measure under the following conditions: Then, Mw was calculated using a calibration curve prepared using polymethyl methacrylate (4 types: Mp (peak molecular weight) = 141,500, 55,600, 11,100, and 1,590) manufactured by Polymer Laboratories. Column: TSK GUARD COLUMN SUPER HH (4.6 x 35 mm, Tosoh Corporation) and two TSK-GEL SUPER HM-H (6.0 x 150 mm, Tosoh Corporation) connected in series. Eluent: tetrahydrofuran. Measurement temperature: 40℃. Flow rate: 0.6mL / min.

[0059] <Monomer conversion rate> The conversion rate (%) of each vinyl monomer was measured using a nuclear magnetic resonance spectrometer (Bruker, Avance, 300 MHz) with CDCl3 as the measurement solvent. 1It was obtained from the measurement value of H-NMR measurement. Specifically, it was calculated as the ratio of the amount of the produced vinyl polymer to the total amount of the remaining vinyl monomer and the amount of the produced vinyl polymer using the integrated value of the peak derived from the remaining vinyl monomer and the integrated value of the peak derived from the produced vinyl polymer.

[0060] <Degree of branching> As an index of the branching degree of a vinyl polymer, the value of Mwabs / Mw calculated from the values ​​of Mwabs and Mw obtained as described above was used. A larger Mwabs / Mw indicates a higher branching degree. Furthermore, the exponent term a, which is calculated by the following method, was also used as an index of the branching degree of the vinyl polymer. First, the absolute molecular weight and intrinsic viscosity at each elution position were calculated by the above-mentioned method, and the slope of their logarithmic plot (Mark-Houwink-Sakurada plot) was calculated as the exponent term a, which is an index of branching. The smaller the exponent term a, the higher the branching degree.

[0061] [Example 1] A polymerizable composition was prepared using MBMA as a chain transfer agent (A), nBA as a vinyl monomer (B), AIBN as a polymerization initiator (C), and anisole as a solvent. The polymerizable composition was prepared so that nBA was 4.5 mol / L (100 mol parts), MBMA was 0.45 mol / L (10 mol parts), and AIBN was 9 mmol / L (0.2 mol parts). The resulting polymerizable composition was then placed in a Pyrex (registered trademark) ampoule, and freezing, degassing, and thawing were repeated three times to remove dissolved oxygen, and then the ampoule was heat-sealed and sealed. The sealed ampoule was then kept at 60°C for 21 hours, and then cooled with a dry ice / methanol cryogen to terminate the polymerization. The sealed tube was opened, and the remaining vinyl monomer (B) was distilled off under reduced pressure to purify the mixture, thereby obtaining a vinyl polymer. The conversion rate of the vinyl monomer (B) and the evaluation results of the obtained vinyl polymer are shown in Table 1.

[0062] [Examples 2 to 5, Comparative Examples 1 to 3] Polymerizable compositions were prepared in the same manner as in Example 1, except that the amounts of the chain transfer agent (A), the vinyl monomer (B) and the polymerization initiator (C) used were changed as shown in Table 1. Next, a vinyl polymer was obtained in the same manner as in Example 1, except that the polymerization time was changed as shown in Table 1. The conversion rate of the vinyl monomer (B) and the evaluation results of the obtained vinyl polymer are shown in Table 1.

[0063] [Table 1]

[0064] As shown in Table 1, in Examples 1 to 5, vinyl polymers having the specified structure and physical properties were obtained. When applied to molded bodies or coating films, these vinyl polymers are industrially useful because they have both excellent elastic modulus and mechanical strength due to their high molecular weight and excellent handleability such as low melt viscosity and solution viscosity due to their high branching degree. On the other hand, in Comparative Examples 1 to 3, Mw or Mwabs / Mw do not meet the requirements, and are not industrially preferable. [Industrial Applicability]

[0065] The vinyl polymer of the present invention, when applied to a molded article or a coating film, has excellent elastic modulus and mechanical strength derived from the high molecular weight, and low melt viscosity and solution viscosity derived from the high branching degree, and therefore has excellent handleability and is industrially useful.

Claims

1. A vinyl polymer having a structure represented by the following formulas (1) and (2): In the following formulas (1) and (2), X １ ~X ｎ where x is a ratio of the number of moles of hydrogen atoms to the total number of moles of hydrogen atoms and methyl groups contained in the copolymer, x is 85 mol % or more; The vinyl polymer has an M / M ratio of 1.5 or more, where M is the absolute weight average molecular weight measured with a light scattering detector and M is the relative weight average molecular weight measured with a differential refractometer using a size exclusion chromatograph to a linear standard poly(methyl methacrylate). 【Chemistry 1】 In formula (1), R and R １ ~R ｎ are each independently a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, or a heterocyclic group; Z is a halogen atom or a group derived from a radical polymerization initiator; X １ ~X ｎ are each independently a hydrogen atom, a methyl group, or a structure represented by formula (2), １ ~X ｎ At least one of the above has a structure represented by formula (2), where n is a natural number from 2 to 10,000. 【Chemistry 2】 In formula (2), R and R １ ~R ｎ are each independently a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, or a heterocyclic group; Z is a halogen atom or a group derived from a radical polymerization initiator; X １ ~X ｎ are each independently a hydrogen atom, a methyl group, or a structure represented by formula (2). ｎ and X ｎ In this formula, n is a natural number from 2 to 10,000. R and R in formula (1) １ ~R ｎ and R in formula (2) １ ~R ｎ are independent of each other, and X in formula (1) １ ~X ｎ and X in formula (2) １ ~X ｎ are independent of each other.

2. The vinyl polymer according to claim 1, wherein the Mw is 20,000 or more.

3. The vinyl polymer according to claim 1 or 2, wherein the Mw is 50,000 or more.

4. A step (i) of preparing a polymerizable composition comprising a chain transfer agent (A) represented by the following formula (3), a vinyl monomer (B), and a polymerization initiator (C); (ii) polymerizing the polymerizable composition; The method for producing a vinyl polymer according to any one of claims 1 to 3, comprising: 【Chemistry 3】 In formula (3), R' is a hydrogen atom, a halogen atom, -OC(O)R", -CONH ２ , -CN, -COOR" or an aryl group, and Y is -SR", a halogen atom, -SO ２ R”, ​​-P(O)(OR”) ２ , -SnR" ３ , -SiR ３ or -OOR". In R' and Y, R" is an alkyl group, a cycloalkyl group, an aryl group, or a heterocyclic group.

5. The method for producing a vinyl polymer according to claim 4, wherein the conversion rate of the vinyl monomer (B) in the step (ii) is 85% or more.

6. 6. The method for producing a vinyl polymer according to claim 4, wherein the content of the chain transfer agent (A) in the polymerizable composition is 0.1 to 20 mol per 100 mol of the vinyl monomer (B).

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