CN110167981B

CN110167981B - Copolymer and resin composition

Info

Publication number: CN110167981B
Application number: CN201880006664.5A
Authority: CN
Inventors: 中西秀高; 井本慎也
Original assignee: Nippon Shokubai Co Ltd
Current assignee: Nippon Shokubai Co Ltd
Priority date: 2017-01-13
Filing date: 2018-01-12
Publication date: 2022-04-08
Anticipated expiration: 2038-01-12
Also published as: JP6732952B2; JPWO2018131670A1; JP2019123854A; KR102190057B1; CN110167981A; KR20190055838A; WO2018131670A1

Abstract

The invention discloses a copolymer, which contains: a copolymer comprising a polymer chain (A) having a unit derived from a diene and/or an olefin, and a polymer chain (B) having a unit derived from a (meth) acrylic monomer and a unit having a ring structure in the main chain, wherein the content of the unit derived from a (meth) acrylic acid ester in the polymer chain (B) is 45 to 98 mass%.

Description

Copolymer and resin composition

Technical Field

The present invention relates to a copolymer, a resin composition containing the copolymer, an optical film, a polarizing plate, an image display device and a method for producing the copolymer, wherein the copolymer contains: a polymer chain having a unit derived from a diene and/or an olefin, and a polymer chain having a unit derived from a (meth) acrylic monomer and a unit having a ring structure in the main chain.

Background

Transparent resins are widely used as optical materials for optical lenses, prisms, mirrors, optical disks, optical fibers, sheets for liquid crystal displays, films, light guide plates, and the like. As such a transparent resin, (meth) acrylic resins have been widely used in the past, but it may be difficult to obtain both heat resistance and mechanical strength from (meth) acrylic resins. For example, a (meth) acrylic resin can improve heat resistance while maintaining transparency by introducing a ring structure into the main chain (patent document 1 and the like), but introduction of a ring structure into the main chain causes the resin itself to be hard and brittle and to be easily broken, and tends to reduce mechanical strength such as folding strength in film processing. As a method for improving the strength of a (meth) acrylic resin, patent document 2 discloses a method for imparting strength by biaxial stretching, and patent document 3 discloses a method for blending a flexible resin having a low glass transition temperature. However, when strength is imparted by biaxial stretching, there is a problem that anisotropy in strength occurs due to the stretching ratio and the like. In addition, when a flexible resin is blended, it is difficult to ensure transparency at the same time, and there is still room for improvement. Patent document 4 discloses a copolymer obtained by grafting a (meth) acrylic polymer onto a polyolefin, but such a graft copolymer has a low glass transition temperature and insufficient heat resistance, and thus there is still room for improvement. Further, when a transparent resin is applied to an optical material, the inclusion of a gelled substance in the resin is undesirable because it causes foreign matter and poor appearance, and also causes low production efficiency.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open No. 2006-171464

Patent document 2: japanese patent laid-open publication No. 2005-162835

Patent document 3: japanese laid-open patent publication No. 2007-100044

Patent document 4: japanese laid-open patent publication No. 5-295183

Disclosure of Invention

The present invention has been made in view of the above circumstances, and an object thereof is to provide a copolymer which has excellent transparency, mechanical strength and heat resistance in a well-balanced manner and generates little gelled substance, a resin composition containing the copolymer, and a method for producing the copolymer.

The present invention includes the following inventions.

[1] A copolymer comprising: a polymer chain (A) having a unit derived from a diene and/or an olefin, and a polymer chain (B) having a unit derived from a (meth) acrylic monomer and a unit having a ring structure in the main chain,

in the polymer chain (B), the content ratio of the unit derived from a (meth) acrylate is 45% by mass or more and 98% by mass or less.

[2] The copolymer according to [1], wherein the polymer chain (B) is a polymer chain grafted to the polymer chain (A).

[3] The copolymer according to [1] or [2], wherein the ring structure is a lactone ring structure and/or a maleimide structure.

[4] The copolymer according to any one of [1] to [3], wherein a total content ratio of the unit derived from the (meth) acrylic monomer and the unit having a ring structure in the main chain in the polymer chain (B) is 90% by mass or more.

[5] A resin composition comprising the copolymer according to any one of [1] to [4] and a (meth) acrylic polymer.

[6] The resin composition according to [5], wherein the (meth) acrylic polymer has the unit derived from the (meth) acrylic monomer.

[7] The resin composition according to [5] or [6], wherein the (meth) acrylic polymer has a unit having a ring structure in the main chain.

[8] The resin composition according to any one of [5] to [7], wherein the resin composition has a glass transition temperature of 100 ℃ or higher and less than 100 ℃.

[9] The resin composition according to any one of [5] to [8], wherein an insoluble matter in chloroform of the resin composition is 10% by mass or less.

[10] An optical film comprising the copolymer according to any one of claims 1 to 4 or the resin composition according to any one of claims 5 to 9.

[11] A polarizing plate comprising the optical film according to [10 ].

[12] An image display device comprising the optical film according to [10 ].

[13] A method for producing the copolymer according to any one of [1] to [4], the method comprising the steps of,

and a step of polymerizing a monomer component containing a (meth) acrylic monomer and a monomer having a polymerizable double bond in a ring structure in the presence of a polymer (P1) having a unit derived from a diene and/or an olefin.

[14] A method for producing the copolymer according to any one of [1] to [4], the method comprising the steps of,

a step of polymerizing a monomer component containing a (meth) acrylic monomer in the presence of a polymer (P1) having a unit derived from a diene and/or an olefin, and

and a step of forming a ring structure on the main chain of the polymer chain having a unit derived from the (meth) acrylic monomer formed in the polymerization step.

[15] The method for producing a copolymer according to [13], wherein the method further comprises: and a step of filtering the resin solution obtained in the polymerization step.

[16] The method for producing a copolymer according to [14], wherein the method further comprises: and a step of filtering the resin solution obtained in the ring structure forming step.

The copolymer and the resin composition containing the copolymer of the present invention have excellent transparency, mechanical strength and heat resistance in a well-balanced manner, and are less likely to generate a gelled product during production. In addition, according to the production method of the present invention, a copolymer which generates little gelled substance and has excellent transparency, mechanical strength and heat resistance in a well-balanced manner can be obtained.

Detailed Description

[ 1. copolymer ]

The copolymer of the present invention contains a diene or olefin polymer chain (A) and a (meth) acrylic polymer chain (B) having a ring structure. The copolymer of the present invention is excellent in transparency, mechanical strength (e.g., impact strength) and heat resistance in a well-balanced manner, and is less likely to produce a gelled product during production. Hereinafter, the copolymer of the present invention is referred to as "copolymer (P)".

The copolymer (P) has a structure obtained by copolymerizing a diene or olefin polymer chain (A) and a (meth) acrylic polymer chain (B) having a ring structure. The copolymerization form is not limited, and is preferably a graft copolymer in which a (meth) acrylic polymer chain (B) having a ring structure is grafted to a diene or olefin polymer chain (A). Hereinafter, the diene or olefin polymer chain (a) is simply referred to as "polymer chain (a)", and the (meth) acrylic polymer chain (B) having a cyclic structure is simply referred to as "polymer chain (B)".

The (meth) acrylic polymer chain (B) having a ring structure generally provides a hard and brittle resin, and by copolymerizing the resin with the diene or olefin polymer chain (a), the composition of the polymer chain (B) is appropriately controlled, whereby the copolymer (P) having both heat resistance and mechanical strength can be obtained. In addition, the production of gelled substances can be reduced during the preparation. The copolymer (P) thus obtained has high transparency even though it contains a diene or olefin component. Further, the copolymer (P) and the (meth) acrylic polymer are blended without impairing the characteristics, and the dispersibility is good without impairing the transparency.

When a film is formed from the copolymer (P), a film having high strength and high heat resistance can be obtained without performing orientation treatment such as stretching treatment. Therefore, a film having desired optical characteristics can be easily obtained. For example, an isotropic film and a low-phase difference film can be efficiently formed because of high strength, high heat resistance, and high transparency. On the other hand, since anisotropy can be easily expressed by the ring structure, a retardation film can be formed by orientation treatment such as stretching treatment. In addition, when the optical film is prepared, foreign matters and appearance defects can be reduced.

The polymer chain (A) contained in the copolymer (P) will be described. The polymer chain (A) has at least units derived from diolefins and/or olefins. Units derived from dienes and/or olefins act as soft components in the copolymer (P). By containing a unit derived from a diene and/or an olefin, the transparency of the copolymer (P) can be ensured, and the mechanical strength (e.g., impact strength) of the copolymer can be improved to reduce the hard brittleness.

As the diene, alkadienes such as 1, 3-butadiene (also known as butadiene), 2-methyl-1, 3-butadiene (also known as isoprene), 1, 3-pentadiene, 1, 4-pentadiene, 1, 5-hexadiene, and 2, 5-dimethyl-1, 5-hexadiene (also known as diisobutylene) are preferably used, and among them, conjugated dienes such as 1, 3-butadiene, 2-methyl-1, 3-butadiene, and 1, 3-pentadiene are more preferably used. As the olefin, monoolefins such as ethylene, propylene, 1-butene, isobutylene, 2-methyl-1-butene, 3-methyl-1-butene, 1-tetradecene, 1-octadecene and the like are preferably used, and among them, α -olefins, which are olefins having a carbon-carbon double bond in the α -position, are more preferred. The number of carbons of these diolefins and olefins is preferably 2 or more, more preferably 3 or more, further preferably 20 or less, more preferably 10 or less, and further preferably 6 or less. Units derived from dienes and/or olefins are defined as units formed by the polymerization of these dienes and/or olefins. The units derived from olefins are not limited to those actually formed by the (co) polymerization of olefins, but may also be formed by the hydrogenation of units derived from diolefins.

The polymer chain (a) includes olefin (co) polymers such as polyethylene, polypropylene, polybutene-1, ethylene-propylene copolymers, ethylene-butene copolymers, etc. in the main chain structure; diene (co) polymers such as polyisoprene, polybutadiene, isoprene-butadiene copolymers, and the like; ethylene-propylene-diene copolymers, isobutylene-isoprene copolymers, and the like. The olefin (co) polymer is preferably an α -olefin (co) polymer, the diene (co) polymer is preferably a conjugated diene (co) polymer, and the copolymer of an olefin and a diene is preferably a copolymer of an α -olefin and a conjugated diene. Among them, a copolymer of an α -olefin and a conjugated diene such as polyisoprene or an isobutylene-isoprene copolymer, polyethylene or polypropylene is more preferable.

The polymer chain (A) may have units derived from other unsaturated monomers in addition to units derived from diolefins and/or olefins. The other unsaturated monomer may be a compound having a polymerizable double bond, and is not particularly limited, and examples thereof include vinyl esters such as vinyl acetate and vinyl propionate; unsaturated carboxylic acids such as (meth) acrylic acid, maleic anhydride, methyl (meth) acrylate, and ethyl (meth) acrylate, and esters thereof; aromatic vinyl compounds such as styrene, vinyltoluene, methoxystyrene, α -methylstyrene, and 2-vinylpyridine; vinyl trimethoxysilane, gamma- (meth) acryloyloxypropylmethoxysilane, and the like. The polymer chain (a) may be a copolymer of these other unsaturated monomers with dienes and/or olefins. The content ratio of the units derived from a diene and/or an olefin in the polymer chain (a) is, for example, preferably 30% by mass or more, more preferably 40% by mass or more, further preferably 50% by mass or more, further preferably 55% by mass or more, and further preferably 90% by mass or less, more preferably 86% by mass or less, and further preferably 83% by mass or less.

When the polymer chain (a) has a unit derived from another unsaturated monomer, the polymer chain (a) may be a random copolymer, a block copolymer or a graft copolymer of a diene and/or an olefin and another unsaturated monomer. Among them, a block copolymer is preferable from the viewpoint that units derived from a diene and/or an olefin are suitable for functioning as a soft component. In this case, the polymer chain (a) is a polymer chain containing a polymer block (a1) having units derived from a diene and/or an olefin and a polymer block (a2) having units derived from other unsaturated monomers.

When the polymer chain (a) is a polymer chain containing a polymer block (a2) having units derived from another unsaturated monomer, the polymer block (a2) is preferably composed of units derived from an aromatic vinyl monomer, from the viewpoint of easily ensuring the mechanical strength of the copolymer (P) and improving the transparency. In this case, in the polymer chain (a), the polymer block (a1) functions as a soft component, and the polymer block (a2) functions as a hard component.

The aromatic vinyl monomer for providing the polymer block (a2) is not particularly limited as long as it is a compound having a vinyl group bonded to an aromatic ring, and examples thereof include styrene monomers such as styrene, vinyltoluene, methoxystyrene, α -methylstyrene, α -hydroxymethylstyrene and α -hydroxyethylstyrene; polycyclic aromatic hydrocarbon cyclic vinyl monomers such as 2-vinylnaphthalene; aromatic heterocyclic vinyl monomers such as N-vinylcarbazole, 2-vinylpyridine, vinylimidazole and vinylthiophene. Among them, styrene monomers are preferable. The styrene-based monomer includes not only styrene but also styrene derivatives having an optional substituent bonded to a carbon atom or a benzene ring of a polymerizable double bond of styrene, and examples of the substituent include an alkyl group, an alkoxy group, a hydroxyl group, a halogen group, an amino group, a nitro group, and a sulfonic acid group. The styrene-bonded alkyl group and alkoxy group are preferably carbon-numbered 1 to 4, more preferably carbon-numbered 1 to 2, and at least a part of hydrogen atoms of the styrene-bonded alkyl group and alkoxy group may be substituted with a hydroxyl group or a halogen group.

As the polymer chain (A) containing the polymer block (a1) having units derived from a diene and/or an olefin and the polymer block (a2) having units derived from an aromatic vinyl monomer, examples thereof include a styrene-butadiene block copolymer, a styrene-butadiene-styrene block copolymer, and a hydrogenated product of a styrene-butadiene-styrene block copolymer (for example, a styrene-ethylene/butylene-styrene block copolymer, a styrene-butadiene/butylene-styrene block copolymer), a styrene-isoprene block copolymer, a styrene-isoprene-styrene block copolymer, and a hydrogenated product of a styrene-isoprene-styrene block copolymer (for example, a styrene-ethylene/propylene-styrene block copolymer).

When the polymer chain (a) contains the polymer block (a1) having units derived from a diene and/or an olefin and the polymer block (a2) having units derived from an aromatic vinyl monomer, it is preferable that the polymer block (a2) is bonded to both sides of the polymer block (a1) of the polymer chain (a). By constituting the polymer chain (a) in this way, the polymer chain (a) functions as an elastomer, and the mechanical strength of the copolymer can be further improved. In this case, the polymer chain (a) may be a triblock copolymer, a multiblock copolymer, or a radial block copolymer, and is preferably a triblock copolymer in view of easy control of the characteristics of the polymer chain (a) and easy introduction of the polymer chain (B) into the copolymer (P).

When the polymer chain (a) contains the polymer block (a1) having units derived from a diene and/or an olefin and the polymer block (a2) having units derived from an aromatic vinyl monomer, the polymer block (a1) may further have units derived from another unsaturated monomer in addition to the units derived from a diene and/or an olefin. Examples of the other unsaturated monomer in this case include vinyl esters such as vinyl acetate and vinyl propionate; unsaturated carboxylic acids such as (meth) acrylic acid, maleic anhydride, methyl (meth) acrylate, and ethyl (meth) acrylate, and esters thereof; aromatic vinyl compounds such as styrene, vinyltoluene, methoxystyrene, α -methylstyrene, and 2-vinylpyridine; vinyl silanes such as vinyltrimethoxysilane and gamma- (meth) acryloyloxypropylmethoxysilane. The polymer block (a1) may be a copolymer of these other unsaturated monomers with dienes and/or olefins. The polymer block (a1) preferably contains a unit derived from a diene and/or an olefin as a main component, and the content of the unit derived from a diene and/or an olefin in 100% by mass of the polymer block (a1) is preferably 50% by mass or more, more preferably 60% by mass or more, and still more preferably 70% by mass or more. The polymer block (a1) may be substantially composed only of units derived from a diene and/or an olefin, and for example, the units derived from a diene and/or an olefin may be 99% by mass or more.

When the polymer chain (a) contains the polymer block (a1) having units derived from a diene and/or an olefin and the polymer block (a2) having units derived from an aromatic vinyl monomer, the polymer block (a2) may further contain units derived from another unsaturated monomer in addition to the units derived from an aromatic vinyl monomer. Examples of the other unsaturated monomer in this case include vinyl esters such as vinyl acetate and vinyl propionate; unsaturated carboxylic acids such as (meth) acrylic acid, maleic anhydride, methyl (meth) acrylate, and ethyl (meth) acrylate, and esters thereof; aromatic vinyl compounds such as styrene, vinyltoluene, methoxystyrene, α -methylstyrene, and 2-vinylpyridine; vinyl silanes such as vinyltrimethoxysilane and gamma- (meth) acryloyloxypropylmethoxysilane. The polymer block (a2) may be a copolymer of these other unsaturated monomers with an aromatic vinyl monomer. The polymer block (a2) preferably contains units derived from an aromatic vinyl monomer as a main component, and the content of the units derived from an aromatic vinyl monomer in 100% by mass of the polymer block (a2) is preferably 70% by mass or more, more preferably 80% by mass or more, and still more preferably 90% by mass or more. The polymer block (a2) may be substantially composed of only units derived from an aromatic vinyl monomer, and for example, the units derived from an aromatic vinyl monomer may be 99% by mass or more.

The content ratio of the polymer block (a2) in the polymer chain (a) is preferably 10% by mass or more, more preferably 14% by mass or more, further preferably 17% by mass or more, and further preferably 55% by mass or less, more preferably 50% by mass or less, further preferably 45% by mass or less. Thus, the polymer chain (a) has a soft component and a hard component in a well-balanced manner, and it is easy to improve the transparency while ensuring the mechanical strength of the copolymer (P). From the same viewpoint, the content ratio of the polymer block (a1) in the polymer chain (a) is preferably 45% by mass or more, more preferably 50% by mass or more, further preferably 55% by mass or more, and further preferably 90% by mass or less, more preferably 86% by mass or less, further preferably 83% by mass or less.

The weight average molecular weight of the polymer chain (a) is preferably 0.1 ten thousand or more, more preferably 0.5 ten thousand or more, further preferably 1 ten thousand or more, further preferably 3 ten thousand or more, further preferably 50 ten thousand or less, more preferably 30 ten thousand or less, further preferably 20 ten thousand or less, further preferably 10 ten thousand or less. When the weight average molecular weight of the polymer chain (a) is in such a range, the strength and transparency of the copolymer (P) can be easily ensured.

The polymer chain (B) contained in the copolymer (P) will be described. The polymer chain (B) has at least a unit derived from a (meth) acrylic monomer and has a ring structure. The polymer chain (B) is preferably grafted to the polymer chain (a), and therefore, the copolymer (P) is a graft copolymer, and the graft chain of the graft copolymer preferably has the polymer chain (B). The transparency of the copolymer (P) can be improved by the polymer chain (B).

The unit derived from a (meth) acrylic monomer (hereinafter also referred to as a "(meth) acrylic acid unit") of the polymer chain (B) can be introduced into the polymer chain (B) by polymerizing the (meth) acrylic monomer. The (meth) acrylic monomer contains (meth) acrylic acid and a derivative thereof, and an alkyl group (preferably an alkyl group having 1 to 4 carbon atoms) may be bonded to the α -position or β -position of the (meth) acrylic monomer, and at least a part of the hydrogen atoms of the alkyl group may be substituted with a hydroxyl group or a halogen group. The form of the carboxylic acid group contained in the unit derived from the (meth) acrylic monomer is not particularly limited, and examples thereof include forms of a free acid, an ester, a salt, an amide, and the like.

The polymer chain (B) has at least a unit derived from a (meth) acrylate as a (meth) acrylic acid unit. Examples of the (meth) acrylate providing the unit derived from the (meth) acrylate include (meth) acrylates in which a linear, branched or cyclic aliphatic hydrocarbon group or aromatic hydrocarbon group is bonded to an oxygen atom of an ester bond of the (meth) acrylic acid.

Examples of the (meth) acrylic ester having a linear or branched aliphatic hydrocarbon group include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, sec-butyl (meth) acrylate, tert-butyl (meth) acrylate, pentyl (meth) acrylate, and isopentyl (meth) acrylate, alkyl (meth) acrylates such as n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, decyl (meth) acrylate, dodecyl (meth) acrylate, pentadecyl (meth) acrylate, hexadecyl (meth) acrylate, heptadecyl (meth) acrylate, and octadecyl (meth) acrylate. The alkyl group of the alkyl (meth) acrylate is preferably a C1-18 alkyl group, more preferably a C1-12 alkyl group. In the present specification, the expressions "C1-18" and "C1-12" mean "C1-18" and "C1-12", respectively.

Examples of the (meth) acrylate having a cyclic aliphatic hydrocarbon group include cycloalkyl (meth) acrylates such as cyclopropyl (meth) acrylate, cyclobutyl (meth) acrylate, cyclopentyl (meth) acrylate, and cyclohexyl (meth) acrylate; and crosslinked cyclic (meth) acrylates such as isobornyl (meth) acrylate. The cycloalkyl group of the cycloalkyl (meth) acrylate is preferably a C3-20 cycloalkyl group, more preferably a C3-12 cycloalkyl group.

Examples of the (meth) acrylate having an aromatic hydrocarbon group include aryl (meth) acrylates such as phenyl (meth) acrylate, methylphenyl (meth) acrylate, dimethylphenyl (meth) acrylate, naphthyl (meth) acrylate, binaphthyl (meth) acrylate, and anthracenyl (meth) acrylate; aralkyl (meth) acrylates such as benzyl (meth) acrylate; and aryloxyalkyl (meth) acrylates such as phenoxyethyl (meth) acrylate. The aryl group of the aryl (meth) acrylate is preferably a C6-20 aryl group, more preferably a C6-14 aryl group. Aralkyl of aralkyl (meth) acrylate is preferably C6-10 aryl C1-4 alkyl. The aryloxyalkyl group of the aryloxyalkyl (meth) acrylate is preferably a C6-10 aryloxyc 1-4 alkyl group, more preferably a phenoxy C1-4 alkyl group.

The (meth) acrylate may have a substituent such as a hydroxyl group, a halogen group, an alkoxy group, or an epoxy group. Examples of such (meth) acrylic acid esters include hydroxyalkyl (meth) acrylates such as 2-hydroxyethyl (meth) acrylate; halogenated alkyl (meth) acrylates such as chloromethyl (meth) acrylate and 2-chloromethyl (meth) acrylate; alkoxyalkyl (meth) acrylates such as 2-methoxyethyl (meth) acrylate; and epoxy alkyl (meth) acrylates such as glycidyl (meth) acrylate. The alkyl group of the hydroxyalkyl (meth) acrylate and the epoxyalkyl (meth) acrylate is preferably a C1-12 alkyl group. The alkoxyalkyl group of the alkoxyalkyl (meth) acrylate is preferably a C1-12 alkoxy C1-12 alkyl group.

The polymer chain (B) has a unit having a ring structure in the main chain (hereinafter also referred to as "ring structure unit") in addition to the (meth) acrylic acid unit. The polymer chain (B) has a ring structure in the main chain, and thus the heat resistance of the copolymer (P) can be improved. Further, it is expected to improve solvent resistance, surface hardness, adhesion, barrier properties against oxygen and water vapor, and various optical properties. Further, when the copolymer (P) or the resin composition containing the copolymer (P) is used as a film or a sheet, dimensional stability and shape stability under high-temperature and high-humidity conditions can be improved. By stretching the film thus formed, a large retardation derived from the ring structure of the polymer chain (B) can be generated, and the film can be used as a retardation film. Due to this feature, the copolymer (P) or the resin composition containing the copolymer (P) can be used as an optical film such as a retardation film or a polarizer protective film having a function as a retardation film.

The ring structure of the main chain of the polymer chain (B) may be a ring structure in which a part or all of the (meth) acrylic monomer is included in the ring structure, or a ring structure introduced separately from the (meth) acrylic monomer. When a part or all of the (meth) acrylic monomer is included in the ring structure, for example, the linkage may be performed by anhydrizing or imidizing 2 carboxylic acid groups of adjacent units derived from the (meth) acrylic monomer. In addition, in the case where one of the adjacent units derived from the (meth) acrylic monomer has a group containing a protic hydrogen atom such as a hydroxyl group or an amino group, the group containing a protic hydrogen atom of the one unit derived from the (meth) acrylic monomer may be condensed with a carboxylic acid group of the other unit derived from the (meth) acrylic monomer to form a ring structure. When the units derived from the (meth) acrylic monomer are each introduced into a ring structure, for example, the (meth) acrylic monomer may be copolymerized with a monomer having a polymerizable double bond in the ring structure.

The ring structure may be any of a 4-membered ring structure, a 5-membered ring structure, a 6-membered ring structure, a 7-membered ring structure, an 8-membered ring structure, and the like, and is preferably a 5-membered ring structure or a 6-membered ring structure.

The ring structure is preferably a lactone ring structure, a cyclic imide structure (e.g., a maleimide structure, a glutarimide structure, etc.), a cyclic anhydride structure (e.g., a maleic anhydride structure, a glutaric anhydride structure, etc.), or the like, from the viewpoint of heat resistance of the copolymer (P). The main chain of the polymer chain (B) may contain only 1 kind of these ring structures, or may contain 2 or more kinds. Among them, at least one selected from the group consisting of a lactone ring structure, a maleimide structure, a maleic anhydride structure, a glutarimide structure and a glutaric anhydride structure is preferable.

When the polymer chain (B) contains a lactone ring structure as the ring structure of the main chain, the number of ring members of the lactone ring structure is not particularly limited, and may be any of 4-to 8-membered rings, for example. In addition, the lactone ring structure is preferably a 5-membered ring or a 6-membered ring, and more preferably a 6-membered ring, from the viewpoint of excellent stability of the ring structure.

The lactone ring structure may be, for example, the structure disclosed in Japanese patent laid-open No. 2004-168882, and the structure represented by the following formula (1) is preferred for reasons such as easy introduction of the lactone ring structure, specifically, high polymerization yield of the precursor (the polymer before cyclization of the lactone), an increase in the lactone ring content in the cyclized condensation reaction of the precursor, and the availability of a polymer having a unit derived from a (meth) acrylate as a precursor. In the following formula (1), R¹、R²And R³Each independently represents a hydrogen atom or a substituent.

[ chemical formula 1]

R as formula (1)¹、R²And R³Examples of the substituent(s) include organic residues such as hydrocarbon groups, and examples thereof include C1-20 hydrocarbon groups optionally containing an oxygen atom. Examples of the hydrocarbon group include a saturated or unsaturated linear, branched or cyclic aliphatic hydrocarbon group and an aromatic hydrocarbon group. Examples of the aliphatic hydrocarbon group include C1-20 alkyl groups such as methyl, ethyl, n-propyl and isopropyl; c2-20 alkenyl groups such as vinyl and propenyl; c3-20 cycloalkyl such as cyclopentyl and cyclohexyl. Examples of the aromatic hydrocarbon group include a C6-20 aryl group such as a phenyl group, tolyl group, xylyl group, naphthyl group, biphenyl group, etc.; c7-20 aralkyl groups such as benzyl and phenethyl. These hydrocarbon groups may contain an oxygen atom, and specifically, one or more of the hydrogen atoms contained in the hydrocarbon groups may be substituted with at least one group selected from a hydroxyl group, a carboxyl group, an ether group and an ester group.

For example, a lactone ring structure can be introduced into the polymer chain (B) by cyclizing condensation of an ester group of an adjacent unit derived from a (meth) acrylate and a group containing a protic hydrogen atom of a unit derived from a (meth) acrylic monomer having a group containing a protic hydrogen atom such as a hydroxyl group or an amino group.

Among the lactone ring structures of the formula (1), R is preferable from the viewpoint of easily obtaining a copolymer (P) having excellent heat resistance and a small birefringence¹And R²Each independently is a hydrogen atom or a C1-20 alkyl group, R³Is a hydrogen atom or a methyl group; more preferably R¹And R²Each independently being a hydrogen atom or a methyl group, R³Is a hydrogen atom or a methyl group.

The lactone ring structure can be formed, for example, by introducing a hydroxyl group and an ester group or a carboxyl group into a molecular chain by polymerizing (preferably copolymerizing) a (meth) acrylic monomer a having a hydroxyl group and a (meth) acrylic monomer B, and then subjecting these hydroxyl group and ester group or carboxyl group to dealcoholization or cyclodehydration. As the polymerization component, a (meth) acrylic monomer a having a hydroxyl group is essential, and a (meth) acrylic monomer B contains the monomer a. The monomer B may or may not be identical to the monomer A. When monomer B is identical to monomer A, homopolymerization of monomer A is carried out.

Examples of the (meth) acrylic monomer a having a hydroxyl group include 2- (hydroxymethyl) acrylic acid, 2- (hydroxyethyl) acrylic acid, and alkyl 2- (hydroxymethyl) acrylates (for example, methyl 2- (hydroxymethyl) acrylate, ethyl 2- (hydroxymethyl) acrylate, isopropyl 2- (hydroxymethyl) acrylate, n-butyl 2- (hydroxymethyl) acrylate, tert-butyl 2- (hydroxymethyl) acrylate), and alkyl 2- (hydroxyethyl) acrylates (for example, methyl 2- (hydroxyethyl) acrylate and ethyl 2- (hydroxyethyl) acrylate), and preferably, 2- (hydroxymethyl) acrylic acid or alkyl 2- (hydroxymethyl) acrylate as a monomer having a hydroxypropenyl moiety. Particularly, methyl 2- (hydroxymethyl) acrylate and ethyl 2- (hydroxymethyl) acrylate are preferable.

The (meth) acrylic monomer B is preferably a monomer having a vinyl group and an ester group or a carboxyl group, examples thereof include (meth) acrylic acid, alkyl (meth) acrylates (e.g., methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, cyclohexyl (meth) acrylate, etc.), aryl (meth) acrylates (e.g., phenyl (meth) acrylate, benzyl (meth) acrylate, etc.), alkyl 2- (hydroxyalkyl) acrylates (e.g., alkyl 2- (hydroxymethyl) acrylates such as methyl 2- (hydroxymethyl) acrylate and ethyl 2- (hydroxymethyl) acrylate, and alkyl 2- (hydroxyethyl) acrylates such as methyl 2- (hydroxyethyl) acrylate).

The polymer chain (B) may contain only 1 lactone ring structure represented by formula (1), or may have 2 or more.

When the polymer chain (B) has a ring structure having a maleic anhydride structure or a maleimide structure as a main chain, the structure represented by the following formula (2) is preferably shown as the maleic anhydride structure or the maleimide structure. In the following formula (2), R⁴And R⁵Each independently represents a hydrogen atom or a methyl group, R⁶Represents a hydrogen atom orSubstituent group, X¹Represents an oxygen atom or a nitrogen atom, X¹When it is an oxygen atom, n1 is 0, X¹And n1 is 1 when it is a nitrogen atom.

[ chemical formula 2]

R as formula (2)⁶Examples of the substituent(s) include a hydrocarbon group and the like, and examples thereof include a C1-20 hydrocarbon group optionally having a substituent such as a halogen. Examples of the hydrocarbon group include a saturated or unsaturated linear, branched or cyclic aliphatic hydrocarbon group and an aromatic hydrocarbon group. Examples of the aliphatic hydrocarbon group include C1-6 alkyl groups such as methyl, ethyl, n-propyl and isopropyl; c2-6 alkenyl groups such as vinyl and propenyl; c3-20 cycloalkyl such as cyclopentyl and cyclohexyl. Examples of the aromatic hydrocarbon group include a C6-20 aryl group such as a phenyl group, tolyl group, xylyl group, naphthyl group, biphenyl group, etc.; c7-20 aralkyl groups such as benzyl and phenethyl. These hydrocarbon groups may have a substituent such as halogen.

X¹In the case of an oxygen atom, the ring structure represented by formula (2) is a maleic anhydride structure. For example, by copolymerizing maleic anhydride with a (meth) acrylic monomer (e.g., (meth) acrylate ester or the like), a maleic anhydride structure can be introduced into the polymer chain (B).

X¹In the case of a nitrogen atom, the ring structure represented by formula (2) is a maleimide structure. The maleimide structure can be introduced into the polymer chain (B), for example, by copolymerizing maleimide with a (meth) acrylic monomer (e.g., (meth) acrylate). Examples of the maleimide structure include a maleimide structure unsubstituted at the N-position, an N-methylmaleimide structure, an N-ethylmaleimide structure, an N-cyclohexylmaleimide structure, an N-phenylmaleimide structure, an N-naphthylmaleimide structure, and an N-benzylmaleimide structure. In addition, as the maleimide providing the maleimide structure, maleimide unsubstituted at the N-position, N-methylmaleimide, N-ethylmaleimide, N-ring may be usedHexylmaleimide, N-phenylmaleimide, N-naphthylmaleimide, N-benzylmaleimide, and the like.

The polymer chain (B) is of X¹In the case of a maleimide structure having a nitrogen atom, R is preferably R from the viewpoint of easily obtaining a copolymer (P) having excellent heat resistance and a small birefringence⁴And R⁵Is a hydrogen atom, R⁶Is a C3-20 cycloalkyl group or a C6-20 aromatic group (aryl, aralkyl, etc.); more preferably R⁴And R⁵Is a hydrogen atom, R⁶Cyclohexyl or phenyl.

The polymer chain (B) may have only 1 kind of ring structure represented by formula (2), or may have 2 or more kinds.

When the polymer chain (B) has a ring structure having a glutarimide structure or a glutaric anhydride structure as a main chain, the glutarimide structure or the glutaric anhydride structure preferably has a structure represented by the following formula (3). In the following formula (3), R⁷And R⁸Each independently represents a hydrogen atom or an alkyl group, R⁹Represents a hydrogen atom or a substituent, X²Represents an oxygen atom or a nitrogen atom, X²When it is an oxygen atom, n2 is 0, X²And n2 is 1 when it is a nitrogen atom.

[ chemical formula 3]

In the formula (3), as R⁷And R⁸The alkyl group (b) preferably includes a linear or branched alkyl group, and examples thereof include C1-8 alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, n-hexyl, isohexyl, n-heptyl, isoheptyl, n-octyl, and 2-ethylhexyl groups. In addition, from the viewpoint of easily obtaining a copolymer (P) having excellent heat resistance and a small birefringence, R is⁷And R⁸Preferably each independently a hydrogen atom or a C1-4 alkyl group, more preferably a hydrogen atom or a methyl group.

R as formula (3)⁹Examples of the substituent(s) include a hydrocarbon group and the likeExamples thereof include a C1-20 hydrocarbon group optionally having a substituent such as halogen. Examples of the hydrocarbon group include a saturated or unsaturated linear, branched or cyclic aliphatic hydrocarbon group and an aromatic hydrocarbon group. Examples of the aliphatic hydrocarbon group include C1-10 alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, n-hexyl, isohexyl, n-heptyl, isoheptyl, n-octyl, and 2-ethylhexyl groups; c2-10 alkenyl groups such as vinyl and propenyl; c3-12 cycloalkyl such as cyclopropyl, cyclobutyl, cyclopentyl and cyclohexyl. Examples of the aromatic hydrocarbon group include a C6-20 aryl group such as a phenyl group, tolyl group, xylyl group, naphthyl group, biphenyl group, binaphthyl group, or anthracenyl group; c7-20 aralkyl groups such as benzyl and phenethyl. These hydrocarbon groups optionally have a substituent such as halogen. Among them, R is a group having excellent heat resistance and a small birefringence, from the viewpoint of easily obtaining a copolymer (P)⁹Preferably a C1-4 alkyl group, a C3-7 cycloalkyl group, a C6-20 aryl group or a C7-20 aralkyl group, more preferably a methyl group, a cyclohexyl group, a phenyl group or a tolyl group.

X²When it is an oxygen atom, the ring structure represented by formula (3) is a glutaric anhydride structure. For example, by anhydrifying 2 carboxylic acid groups of adjacent units derived from a (meth) acrylic monomer, a glutaric anhydride structure can be introduced into the polymer chain (B).

X²In the case of a nitrogen atom, the ring structure represented by the formula (3) is a glutarimide structure. For example, a glutarimide structure can be introduced into the polymer chain (B) by imidizing 2 carboxylic acid groups of adjacent units derived from a (meth) acrylic monomer, or by cyclizing condensation of an amide group of adjacent units derived from (meth) acrylamide and an ester group of units derived from a (meth) acrylic ester.

Among the ring structures of the formula (3), R is preferable from the viewpoint of easily obtaining a copolymer (P) having excellent heat resistance and a small birefringence⁷And R⁸Each independently being a hydrogen atom or a methyl group, R⁹Is C1-10 alkyl, C3-12 cycloalkyl or C6-20 aromatic group; more preferably R⁷And R⁸Each independently being a hydrogen atom or a methyl group, R⁹Is C1-4 alkyl, C3-7 cycloalkyl, C6-20 aryl or C7-20 aralkyl; further preferred is R⁷And R⁸Each independently being a hydrogen atom or a methyl group, R⁹Is methyl, cyclohexyl, phenyl or tolyl; particular preference is given to R⁷And R⁸Each independently being a hydrogen atom or a methyl group, R⁹Cyclohexyl or phenyl.

The polymer chain (B) may have only 1 kind of ring structure represented by formula (3), or may have 2 or more kinds.

Among the above-described ring structures, when the copolymer (P) or the resin composition containing the copolymer (P) is applied to an optical film, the cyclic structure unit of the polymer chain (B) preferably contains a lactone ring structure and/or a maleimide structure from the viewpoint of imparting good surface hardness, solvent resistance, adhesiveness, barrier properties, and optical properties. When the optical film is a retardation film, a positive retardation can be provided, and from the viewpoint of good stability of retardation characteristics, it is more preferable that the cyclic structure unit of the polymer chain (B) contains a lactone ring structure.

The polymer chain (B) may further have units derived from other unsaturated monomers. The other unsaturated monomer is not particularly limited as long as it is a compound having a polymerizable double bond, and examples thereof include vinyl esters such as vinyl acetate and vinyl propionate; aromatic vinyl compounds such as styrene, vinyltoluene, methoxystyrene, α -methylstyrene, and 2-vinylpyridine; vinyl silanes such as vinyltrimethoxysilane and gamma- (meth) acryloyloxypropylmethoxysilane. For example, when the polymer chain (B) has a unit derived from an aromatic vinyl monomer, the refractive index and retardation characteristics of the copolymer (P) can be easily adjusted. For details of the aromatic vinyl monomer, reference is made to the description of the aromatic vinyl monomer of the polymer block (a 2). When the polymer chain (B) is formed of 2 or more monomer components, the polymer chain (B) is preferably a random copolymer.

In the polymer chain (B), the content ratio of the (meth) acrylate-derived unit in the copolymer (P) is 45 mass% or more and 98 mass% or less. When the content ratio of the unit derived from a (meth) acrylate in the polymer chain (B) is 45% by mass or more, the occurrence of a gelled product can be suppressed when the polymer chain (B) is polymerized, and the copolymer (P) can be easily used for optical applications. In addition, the mechanical strength of the copolymer (P) can be easily improved. When the content ratio of the unit derived from a (meth) acrylate in the polymer chain (B) is 98% by mass or less, the copolymer (P) having excellent heat resistance can be obtained. The content ratio of the (meth) acrylate-derived unit in the polymer chain (B) is preferably 50% by mass or more, more preferably 55% by mass or more, further preferably 60% by mass or more, and further preferably 97% by mass or less.

The content ratio of the cyclic structure unit in the polymer chain (B) is preferably 2% by mass or more, more preferably 3% by mass or more, further preferably 5% by mass or more, and further preferably 50% by mass or less, more preferably 45% by mass or less, further preferably 40% by mass or less. By adjusting the content ratio of the ring structural unit in this manner, it becomes easier to improve both the heat resistance and the mechanical strength of the copolymer (P) in a well-balanced manner. The content ratio of the cyclic structure unit described herein is a content ratio of the unit having a cyclic structure contained in the main chain of the polymer chain (B), and is, for example, a content ratio of the structures represented by the above formulas (1) to (3).

The total content of the (meth) acrylic acid unit and the cyclic structure unit in the polymer chain (B) is preferably 90% by mass or more, more preferably 93% by mass or more, and still more preferably 95% by mass or more. This makes it easy to improve the transparency and heat resistance of the copolymer (P). The total content ratio of the unit derived from the (meth) acrylate and the cyclic structure unit is preferably within such a range.

The polymer chain (B) is preferably grafted onto the polymer chain (A). The polymer chain (B) may be bonded to a unit derived from a diene and/or an olefin of the polymer chain (A), or may be bonded to a unit other than a unit derived from a diene and/or an olefin of the polymer chain (A). In the former case, the polymer chain (B) may be bonded directly to the units derived from the diolefin and/or olefin of the polymer chain (A) or may be bonded via a linking group.

In the case where the polymer chain (B) is directly bonded to the units derived from diolefin and/or olefin of the polymer chain (A), it is preferable that the (meth) acrylic acid units or the ring structure units of the polymer chain (B) are directly bonded to the units derived from diolefin and/or olefin of the polymer chain (A). The polymer chain (B) may be bonded to a carbon atom of the main chain derived from a unit of diene and/or olefin, or may be bonded to a carbon atom of a hydrocarbon group bonded as a substituent (side chain) to the main chain. When the polymer chain (B) is bonded to the polymer chain (A), the copolymer (P) having a small amount of gelled substance can be easily obtained.

In the case where the polymer chain (B) is bonded to the unit derived from a diene and/or an olefin in the polymer chain (A) via a linking group, the linking group preferably has at least one selected from an ester bond (-CO-O-), a urethane bond (-NH-CO-O-) and an ether bond (-O-), and the linking group may have a 2-valent organic group such as a methylene group or a hydroxymethylene group.

When the polymer chain (B) is bonded to a unit other than the unit derived from the diene and/or the olefin in the polymer chain (A), for example, the polymer chain (A) contains a unit having a polymerizable functional group (polymerizable double bond), and the polymer chain (B) is bonded to the polymerizable functional group of the unit, or the polymer chain (A) may be bonded to the polymer chain (B) through a linking group such as an ester bond (-CO-O-), a urethane bond (-NH-CO-O-), an ether bond (-O-) or the like in addition to the unit derived from the diene and/or the olefin. The linking group may further have a 2-valent organic group such as a methylene group or a hydroxymethylene group.

The embodiments of the method for producing the copolymer (P) described above, in which the polymer chain (B) is grafted to the polymer chain (A), are described in detail below.

The content ratio of the cyclic structure unit in the copolymer (P) is not particularly limited, but the content ratio of the cyclic structure unit in the copolymer (P) is, for example, preferably 1% by mass or more, more preferably 3% by mass or more, further preferably 5% by mass or more, further preferably 60% by mass or less, more preferably 50% by mass or less, further preferably 40% by mass or less. By adjusting the content ratio of the cyclic structure unit in the copolymer (P) in this manner, the heat resistance, transparency, moldability, mechanical strength, and the like of the copolymer (P) can be easily improved in a well-balanced manner.

When the copolymer (P) has a lactone ring structure as the ring structure unit of the polymer chain (B), the content of the lactone ring structure in the copolymer (P) is, for example, preferably 1% by mass or more, more preferably 3% by mass or more, further preferably 5% by mass or more, further preferably 60% by mass or less, more preferably 50% by mass or less, and further preferably 40% by mass or less, from the viewpoint of improving the heat resistance and transparency of the copolymer (P). From the same viewpoint, when the copolymer (P) has a maleic anhydride structure and/or a maleimide structure as a cyclic structure unit of the polymer chain (B), the content ratio of these cyclic structures in the copolymer (P) is, for example, preferably 1% by mass or more, more preferably 3% by mass or more, further preferably 5% by mass or more, further preferably 60% by mass or less, more preferably 50% by mass or less, further preferably 40% by mass or less. When the copolymer (P) has a glutarimide structure and/or a glutaric acid anhydride structure as a ring structure unit of the polymer chain (B), the content ratio of these ring structures in the copolymer (P) is, for example, preferably 1% by mass or more, more preferably 3% by mass or more, further preferably 5% by mass or more, further preferably 60% by mass or less, more preferably 50% by mass or less, further preferably 40% by mass or less.

The weight average molecular weight of the copolymer (P) is preferably 0.2 ten thousand or more, more preferably 0.5 ten thousand or more, further preferably 3 ten thousand or more, further preferably 5 ten thousand or more, particularly preferably 7 ten thousand or more, further preferably 100 ten thousand or less, more preferably 50 ten thousand or less, further preferably 30 ten thousand or less, further preferably 20 ten thousand or less. When the weight average molecular weight of the copolymer (P) is in such a range, the molding processability of the copolymer (P) is improved and the strength of the obtained molded article is easily improved.

The weight average molecular weight of the copolymer (P) is preferably 1.1 times or more, more preferably 1.2 times or more, more preferably 1.3 times or more, and further preferably 20 times or less, more preferably 12 times or less, further preferably 10 times or less, further preferably 7 times or less, and particularly preferably 5 times or less, the weight average molecular weight of the polymer chain (a). This makes it possible to impart the copolymer (P) with various properties such as transparency, mechanical strength and heat resistance in a well-balanced manner.

The refractive index of the copolymer (P) is preferably a value close to the refractive index of the polymer chain (a), whereby the transparency of the copolymer (P) can be easily ensured. Specifically, the difference between the refractive index of the copolymer (P) and the refractive index of the polymer chain (a) is preferably less than 0.1, more preferably 0.05 or less, and further preferably 0.02 or less. From the same viewpoint, the refractive index of the polymer chain (a) in the copolymer (P) is preferably a value close to the refractive index of the polymer chain (B), and specifically, the difference between the refractive index of the polymer chain (a) and the refractive index of the polymer chain (B) is preferably less than 0.1, more preferably 0.05 or less, and further preferably 0.02 or less.

The copolymer (P) preferably has a glass transition temperature of 100 ℃ or higher and less than 100 ℃, respectively. The glass transition temperature of 100 ℃ or higher is referred to as "glass transition temperature on the high temperature side", and the glass transition temperature of less than 100 ℃ is referred to as "glass transition temperature on the low temperature side". The copolymer (P) may have a plurality of glass transition temperatures on the high temperature side or a plurality of glass transition temperatures on the low temperature side. The copolymer (P) has a high-temperature glass transition temperature, so that the heat resistance of the copolymer (P) is improved, and the copolymer (P) does not soften even at high temperatures when formed into a film or the like, and the moldability can be improved. The copolymer (P) has a glass transition temperature on the low temperature side, and thus the impact resistance of the copolymer (P) can be improved. The glass transition temperature of the copolymer (P) on the high temperature side is preferably 113 ℃ or higher, more preferably 116 ℃ or higher, and still more preferably 120 ℃ or higher. The glass transition temperature of the low temperature side of the copolymer (P) is preferably less than 50 ℃, more preferably less than 20 ℃, still more preferably less than 0 ℃, and still more preferably less than-20 ℃.

The copolymer (P) can be produced by addition polymerization of monomer components forming the polymer chain (B) to the polymer chain (a). Thus, the process for preparing the copolymer (P) preferably comprises: the step (polymerization step) of polymerizing the monomer component containing the (meth) acrylic monomer in the presence of a polymer having a unit derived from a diene and/or an olefin (hereinafter referred to as "base polymer (P1)") can add-polymerize the monomer component containing the (meth) acrylic monomer to the base polymer (P1). In this case, the monomer component containing the (meth) acrylic monomer may be addition-polymerized with the base polymer (P1) by any of the following methods, for example: (1) a method of directly bonding to a unit derived from a diene and/or an olefin of the base polymer (P1), (2) a method of bonding to a polymerizable functional group of a linking group possessed by a side chain of a unit derived from a diene and/or an olefin of the base polymer (P1), or (3) a method of bonding to a polymerizable functional group possessed by a side chain of a unit other than the unit derived from a diene and/or an olefin of the base polymer (P1). In this case, the resulting copolymer is a graft copolymer. In the present specification, the "base polymer (P1)" is also simply referred to as "polymer (P1)".

The base polymer (P1) may have at least units derived from diolefins and/or olefins, and may further have units derived from other unsaturated monomers. For details of the units derived from diolefin and/or olefin and the units derived from other unsaturated monomers of the base polymer (P1), reference is made to the above description of the units derived from diolefin and/or olefin and the units derived from other unsaturated monomers of the polymer chain (A). In units derived from dienes and/or olefins, a portion of the hydrogen atoms may be chlorinated. The base polymer (P1) may be a block copolymer containing a polymer block (a1) having units derived from a diene and/or an olefin and a polymer block (a2) having units derived from another unsaturated monomer, and the polymer block (a2) may be composed of units derived from an aromatic vinyl monomer. These details can also be referred to the description of the polymer chain (A) above. In the method (2), the base polymer (P1) has a linking group derived from a polymerizable functional group present in a side chain of a unit derived from a diene and/or an olefin, and in the method (3), a unit other than the unit derived from a diene and/or an olefin has a polymerizable functional group in a side chain.

The weight average molecular weight of the base polymer (P1) is preferably 0.1 ten thousand or more, more preferably 0.5 ten thousand or more, further preferably 1 ten thousand or more, further preferably 3 ten thousand or more, and further preferably 50 ten thousand or less, more preferably 30 ten thousand or less, further preferably 20 ten thousand or less, and further preferably 10 ten thousand or less. When the weight average molecular weight of the base polymer (P1) is in such a range, the moldability of the copolymer (P) is improved, and the strength and transparency of the copolymer (P) are easily ensured. In addition, the generation of a crosslinked material and a gelled material can be suppressed during the polymerization reaction with the monomer component containing the (meth) acrylic monomer.

In the polymerization step, only 1 type of the base polymer (P1) may be used, or 2 or more types may be used in combination. In the latter case, the average molecular weight and the double bond amount of the resin composition can be easily adjusted.

The monomer component used for forming the polymer chain (B) may be a monomer having a polymerizable double bond in a ring structure, as a monomer providing a ring structure unit, in addition to a (meth) acrylic monomer. For example, when the polymer chain (B) having a maleimide structure in the main chain is formed, a monomer having a polymerizable double bond in the ring structure is preferably used. Alternatively, in the case where the ring structure forming step is performed after the polymerization step, a monomer capable of forming a ring structure in this step may be used as the monomer component. In addition, other unsaturated monomers may be used. For details of these monomer components, reference is made to the (meth) acrylic monomer forming the polymer chain (B), the monomer imparting a ring structure to the polymer chain (B), and other unsaturated monomers forming the polymer chain (B).

The methods (1) to (3) are described in detail below with respect to a method of addition-polymerizing a monomer component containing a (meth) acrylic monomer to the base polymer (P1).

In the method of (1) for directly bonding the monomer component containing the (meth) acrylic monomer to the unit derived from a diene and/or an olefin of the base polymer (P1), the monomer component containing the (meth) acrylic monomer is bonded to the unit derived from a diene and/or an olefin of the base polymer (P1). In this case, the units of the base polymer (P1) derived from diolefins and/or olefins preferably have double bonds derived from diolefins. The monomer component containing the (meth) acrylic monomer may be bonded to a double bond derived from a diene in the main chain of the base polymer (P1), or may be bonded to a carbon atom adjacent to the double bond. Alternatively, the polymer chain (B) may be bonded to a double bond derived from a diene bonded as a substituent (side chain) to the main chain of the base polymer (P1), or may be bonded to a carbon atom adjacent to the double bond. In any of the above cases, the resulting copolymer (P) is a polymer in which the polymer chain (B) is directly bonded to the units derived from the diene and/or the olefin of the polymer chain (A). In this method, it is preferable that highly active hydrogen at a vinyl site, an allyl site, or the like of a double bond (olefinic double bond) derived from a diene and/or an olefin unit in the base polymer (P1) is abstracted, whereby a radical can be generated at the site to cause addition polymerization of a monomer component forming the polymer chain (B).

In the method (2) for bonding a monomer component containing a (meth) acrylic monomer to a polymerizable functional group of a linking group having a side chain of a unit derived from a diene and/or an olefin in the base polymer (P1), the linking group has a polymerizable functional group (polymerizable double bond) and is bonded to a side chain of a unit derived from a diene and/or an olefin. The resulting copolymer (P) is a polymer in which the polymer chain (B) is bonded to units derived from a diene and/or an olefin of the polymer chain (A) via a linking group.

The linking group preferably has at least one selected from an ester bond, a urethane bond, and an ether bond in addition to the polymerizable functional group (polymerizable double bond), and may further have a 2-valent organic group such as a methylene group or a hydroxymethylene group. The base polymer (P1) having such a linking group can be obtained by reacting a polymer having a unit derived from a diene and/or an olefin and having a functional group that provides an ester bond, a urethane bond or an ether bond (hereinafter referred to as "base polymer (P2)") with a compound having a functional group reactive with the functional group and having a polymerizable functional group (hereinafter referred to as "radical polymerizable compound").

The functional group providing an ester bond, a urethane bond or an ether bond means a functional group forming a bond of any one of the above by a reaction with a radical polymerizable compound, and specifically, a carboxyl group or an acid anhydride group thereof, an epoxy group, a hydroxyl group, an isocyanate group and the like are preferable. In order to introduce these functional groups into the base polymer (P2), an unsaturated compound having these functional groups may be reacted with a polymer having units derived from a diene and/or an olefin (for example, the base polymer (P1) used in the production method of the above (1)), and the reaction is usually carried out using a radical initiator.

Examples of the unsaturated compound having a carboxyl group or an acid anhydride group thereof include unsaturated carboxylic acids and acid anhydrides thereof such as (meth) acrylic acid, fumaric acid, maleic acid and acid anhydride thereof, itaconic acid and acid anhydride thereof, crotonic acid and acid anhydride thereof, and citraconic acid and acid anhydride thereof.

Examples of the unsaturated compound having an epoxy group include unsaturated carboxylic acid glycidyl esters such as glycidyl (meth) acrylate, mono-and diglycidyl esters of maleic acid, mono-and diglycidyl esters of itaconic acid, mono-and diglycidyl esters of allyl succinic acid, and glycidyl esters of p-styrene carboxylic acid; glycidyl ethers such as allyl glycidyl ether, 2-methylallyl glycidyl ether, and styrene-p-glycidyl ether; p-glycidyl styrene; epoxy olefins such as 3, 4-epoxy-1-butene and 3, 4-epoxy-3-methyl-1-butene; vinylcyclohexene monooxide, and the like.

Examples of the unsaturated compound having a hydroxyl group include hydroxyalkyl (meth) acrylates such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and 2-hydroxybutyl (meth) acrylate; n-methylol (meth) acrylamide; 2-hydroxyethyl acrylate-6-hexanol addition polymer; enol such as 2-propen-1-ol; alkynols such as 2-propyn-1-ol; hydroxy vinyl ethers, and the like.

Examples of the unsaturated compound having an isocyanate group include 2-isocyanatoethyl (meth) acrylate and methacryloyl isocyanate.

The radical polymerizable compound has a polymerizable functional group (polymerizable double bond) and a functional group reactive with a carboxyl group or an acid anhydride group thereof, an epoxy group, a hydroxyl group, or an isocyanate group. Examples of the reactive functional group include a hydroxyl group, an epoxy group, an isocyanate group, and a carboxyl group.

Examples of the radical polymerizable compound having a hydroxyl group as a reactive functional group include hydroxyalkyl (meth) acrylates such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and 2-hydroxybutyl (meth) acrylate; n-methylol (meth) acrylamide; 2-hydroxyethyl acrylate-6-hexanol addition polymer; enol such as 2-propen-1-ol; alkynols such as 2-propyn-1-ol; hydroxy vinyl ethers, and the like.

Examples of the radical polymerizable compound having an epoxy group having a reactive functional group include glycidyl esters of unsaturated carboxylic acids such as glycidyl (meth) acrylate, mono-and diglycidyl esters of maleic acid, mono-and diglycidyl esters of itaconic acid, mono-and diglycidyl esters of allyl succinic acid, and glycidyl esters of p-styrene carboxylic acid; glycidyl ethers such as allyl glycidyl ether, 2-methylallyl glycidyl ether, and styrene-p-glycidyl ether; p-glycidyl styrene; epoxy olefins such as 3, 4-epoxy-1-butene and 3, 4-epoxy-3-methyl-1-butene; vinylcyclohexene monooxide, and the like.

Examples of the radical polymerizable compound having an isocyanate group as a reactive functional group include 2-isocyanatoethyl (meth) acrylate and methacryloyl isocyanate.

Examples of the radical polymerizable compound having a carboxyl group as a reactive functional group include unsaturated acids such as (meth) acrylic acid; carboxyalkyl vinyl ethers such as carboxyethyl vinyl ether and carboxypropyl vinyl ether.

When the functional group of the base polymer (P2) is a carboxyl group or an acid anhydride group thereof, the reactive functional group of the radical polymerizable compound preferably includes a hydroxyl group, an epoxy group, and an isocyanate group. Among them, a radical polymerizable compound having a hydroxyl group is particularly preferable. In this case, the base polymer (P1) obtained by the reaction of the base polymer (P2) and the radical polymerizable compound is a polymer having a linking group having a polymerizable functional group and an ester bond in a side chain.

When the functional group of the base polymer (P2) is an epoxy group, a carboxyl group and a hydroxyl group are preferably shown as the reactive functional group of the radical polymerizable compound. Among them, a radical polymerizable compound having a carboxyl group is particularly preferable. In this case, the base polymer (P1) obtained by the reaction of the base polymer (P2) with a radically polymerizable compound is a polymer having a linking group having a polymerizable functional group and an ester bond (specifically, -CH (OH) -CH) on a side chain₂-2-valent organic group represented by-OCO-).

When the functional group of the base polymer (P2) is a hydroxyl group, isocyanate group, carboxyl group, and epoxy group are preferable examples of the reactive functional group of the radical polymerizable compound. Among them, radical polymerizable monomers having an isocyanate group are particularly preferable. In this case, the base polymer (P1) obtained by the reaction of the base polymer (P2) and the radical polymerizable compound is a polymer having a linking group having a polymerizable functional group and a urethane bond in a side chain.

When the functional group of the base polymer (P2) is an isocyanate group, a hydroxyl group and a carboxyl group are preferable examples of the reactive functional group of the radical polymerizable compound. Among them, a radical polymerizable monomer having a hydroxyl group is particularly preferable. In this case, the base polymer (P1) obtained by the reaction of the base polymer (P2) and the radical polymerizable compound is a polymer having a linking group having a polymerizable functional group and a urethane bond in a side chain.

Examples of the raw material polymer (P1) usable in the production method of (2) include LIR UC-102M and UC-203 (both manufactured by KURARARAAY corporation) of polyisoprene having a methacryloyl group and an ester bond in a side chain.

The method for producing the copolymer (P) according to (3) will be described. In the method of (3) for bonding a monomer component containing a (meth) acrylic monomer to a polymerizable functional group present in a side chain of a unit other than a unit derived from a diene and/or an olefin, the raw polymer (P1) can be obtained by copolymerizing a diene and/or an olefin with an unsaturated monomer having a polymerizable functional group (polymerizable double bond), or by copolymerizing a diene and/or an olefin with an unsaturated monomer having a functional group containing a carboxyl group or an acid anhydride group thereof, an epoxy group, a hydroxyl group, or an isocyanate group, and further reacting the resultant with the above-described radical polymerizable compound having a reactive functional group. Alternatively, the base polymer (P1) can be obtained by polymerizing a (co) polymer having a unit derived from a diene and/or an olefin with an unsaturated monomer having a polymerizable functional group (polymerizable double bond), or polymerizing a (co) polymer having a unit derived from a diene and/or an olefin with an unsaturated monomer having a carboxyl group or an acid anhydride group thereof, an epoxy group, a hydroxyl group or an isocyanate group, and further reacting the resultant with the above-described radical polymerizable compound having a reactive functional group. In the presence of the thus obtained base polymer (P1), a copolymer (P) is obtained by polymerizing a monomer component containing a (meth) acrylic monomer. The resulting copolymer (P) is a polymer in which the polymer chain (B) is bonded to units other than the units derived from the diene and/or olefin of the polymer chain (A).

When a (co) polymer having a diene and/or an olefin or a unit derived therefrom is polymerized with an unsaturated monomer having a polymerizable functional group, examples of the unsaturated monomer having a polymerizable functional group include polyfunctional (meth) acrylic compounds such as polyfunctional (meth) acrylate, vinyl ether group-containing (meth) acrylate, and allyl group-containing (meth) acrylate, polyfunctional vinyl ethers, polyfunctional allyl compounds, and polyfunctional aromatic vinyl compounds.

Examples of the polyfunctional (meth) acrylate include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, hexanediol di (meth) acrylate, bisphenol a alkylene oxide di (meth) acrylate, trimethylolpropane tri (meth) acrylate, 2'- [ oxybis (methylene) ] bisacrylic acid, dialkyl-2, 2' - [ oxybis (methylene) ] bis-2-acrylate, and the like.

Examples of the vinyl ether group-containing (meth) acrylate include 2-vinyloxyethyl (meth) acrylate, 4-vinyloxybutyl (meth) acrylate, and 2- (vinyloxyethoxy) ethyl (meth) acrylate.

Examples of the allyl group-containing (meth) acrylate include allyl (meth) acrylate, α -allyloxymethylacrylate, α -allyloxymethylmethacrylate octadecyl ester, α -allyloxymethylacrylate 2-decyltetradecyl ester, and the like.

Examples of the polyfunctional vinyl ether include ethylene glycol divinyl ether, diethylene glycol divinyl ether, polyethylene glycol divinyl ether, hexanediol divinyl ether, bisphenol a alkylene oxide divinyl ether, trimethylolpropane trivinyl ether, and the like.

Examples of the polyfunctional allyl compounds include polyfunctional allyl ethers such as ethylene glycol diallyl ether, diethylene glycol diallyl ether, polyethylene glycol diallyl ether, hexanediol diallyl ether, bisphenol a alkylene oxide diallyl ether, trimethylolpropane triallyl ether, ditrimethylolpropane tetraallyl ether, and the like; polyfunctional allyl-containing isocyanurates such as triallyl isocyanurate; polyfunctional allyl esters of diallyl phthalate, diallyl bibenzoate, and the like; diallyl nadiimide compounds and the like; diallyl nadiimide compounds, and the like.

Examples of the polyfunctional aromatic vinyl compound include divinylbenzene and the like.

When a (co) polymer having a diene and/or an olefin or a unit derived therefrom is polymerized with an unsaturated monomer having a carboxyl group or an acid anhydride group thereof, an epoxy group, a hydroxyl group or an isocyanate group functional group, the resulting polymer (hereinafter referred to as "base polymer (P3)") has a unit derived from a diene and/or an olefin and a unit other than the unit derived from a diene and/or an olefin, and a functional group having a carboxyl group or an acid anhydride group thereof, an epoxy group, a hydroxyl group or an isocyanate group is bonded to a side chain of the other unit. Examples of the base polymer (P3) include an ethylene- (meth) acrylic acid copolymer, an ethylene-2-hydroxyethyl (meth) acrylate copolymer, an ethylene-glycidyl (meth) acrylate copolymer, an ethylene-polyethylene glycol mono (meth) acrylate copolymer, an ethylene-vinyl acetate- (meth) acrylic acid copolymer, an ethylene- (meth) acrylic acid ethyl ester-maleic acid (anhydride) copolymer, an ethylene-vinyl acetate-2-hydroxyethyl (meth) acrylate copolymer, an ethylene-vinyl acetate-glycidyl (meth) acrylate copolymer, an ethylene-vinyl acetate-polyethylene glycol mono (meth) acrylate copolymer, a copolymer, and a copolymer, And partially saponified ethylene-vinyl acetate copolymers. Among them, preferred are an ethylene- (meth) acrylic acid copolymer, an ethylene- (meth) acrylic acid ethyl ester-maleic acid (anhydride) copolymer, and an ethylene-vinyl acetate-glycidyl (meth) acrylate copolymer.

The base polymer (P1) is obtained by reacting the base polymer (P3) with the radical polymerizable compound having a reactive functional group described above. For details of the functional group of the base polymer (P3) and the reactive functional group of the radical polymerizable compound, reference is made to the above-mentioned description of the method (2).

In the reaction of the base polymer (P2) with the radical polymerizable compound in the method (2) or the reaction of the base polymer (P3) with the radical polymerizable compound in the method (3), the reactive functional group of the radical polymerizable compound is preferably blended so that it is 0.1 to 10 equivalents relative to 1 equivalent of the functional group in the base polymer (P2) or the base polymer (P3) and reacted. This improves the yield of the finally obtained copolymer (P).

The above reaction is preferably carried out in an appropriate organic solvent, and examples of the organic solvent include toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, butyl acetate, cellosolve acetate, and the like. The reaction temperature is usually 20 ℃ to 150 ℃, preferably 50 ℃ to 120 ℃.

The reaction of the base polymer (P2) or the base polymer (P3) with the radically polymerizable compound is preferably carried out in the presence of a catalyst. As the catalyst, an acid or basic compound such as sulfuric acid, p-toluenesulfonic acid, zinc chloride, pyridine, triethylamine, dimethylbenzylamine or the like can be used in the esterification reaction, and dibutyltin laurate or the like can be used in the carbamation reaction.

In the reaction, it is also preferable to react under an oxygen or air atmosphere in order to prevent the formation of a homopolymer of the vinyl monomer, and an appropriate amount of a polymerization inhibitor such as hydroquinone, hydroquinone monomethyl ether, phenothiazine, etc. is added to the reaction system.

In the methods (1) to (3), the copolymer (P) can be obtained by polymerizing a monomer component containing a (meth) acrylic monomer (which may further contain a monomer having a polymerizable double bond in a ring structure if necessary) in the presence of the base polymer (P1) obtained as described above. Preferably, the copolymer (P) is obtained by graft polymerizing a monomer component containing a (meth) acrylic monomer with the base polymer (P1). The amount of each monomer component containing a (meth) acrylic monomer can be appropriately adjusted so that the content ratio of the unit derived from a (meth) acrylic ester in the polymer chain (B) to be finally obtained falls within a desired range. From the viewpoint of easily suppressing the formation of a gelled product in the polymerization step, it is preferable to polymerize the monomer component containing the (meth) acrylic monomer in the presence of the base polymer (P1) by the method (1). In the methods (2) and (3), the production of gelled products can be suppressed by controlling the polymerization reaction by setting a short polymerization reaction time or the like.

The polymerization of the monomer component may be carried out by any known polymerization method such as bulk polymerization, solution polymerization, emulsion polymerization, or suspension polymerization, and preferably by solution polymerization. When the solution polymerization method is used, it is possible to suppress the incorporation of fine foreign matters into the copolymer (P), and the copolymer (P) can be more easily applied to optical material applications and the like.

As the polymerization form, for example, either a batch polymerization method or a continuous polymerization method can be used. The monomer components may be added together or in portions during the polymerization.

The polymerization solvent may be appropriately selected depending on the composition of the monomer component, and an organic solvent used in a general radical polymerization reaction may be used. Specific examples thereof include aromatic hydrocarbons such as toluene, xylene, and ethylbenzene; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ethers such as tetrahydrofuran, dioxane, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether and anisole; esters such as ethyl acetate, butyl acetate, propylene glycol monomethyl ether acetate, and 3-methoxybutyl acetate; cellosolves such as methyl cellosolve, ethyl cellosolve, and butyl cellosolve; alcohols such as methanol, ethanol, isopropanol, and n-butanol; nitriles such as acetonitrile, propionitrile, butyronitrile, and benzonitrile; chloroform; dimethyl sulfoxide, and the like. These solvents may be used alone in 1 kind, or 2 or more kinds may be used in combination.

The polymerization reaction of the base polymer (P1) and the monomer component is preferably carried out in the presence of a polymerization catalyst (polymerization initiator). As the polymerization catalyst, for example, azo compounds such as 2,2 '-azobisisobutyronitrile, 2' -azobis (2-amidinopropane) dihydrochloride, dimethyl-2, 2 '-azobis (2-methylpropionate), 4' -azobis (4-cyanopentanoic acid), and the like; persulfates such as potassium persulfate; and organic peroxides such as cumene hydroperoxide, diisopropylbenzene hydroperoxide, di-t-butyl peroxide, lauroyl peroxide, benzoyl peroxide, t-butyl peroxy isopropyl carbonate, t-amyl peroxy-2-ethylhexanoate, t-amyl peroxy octanoate, t-amyl peroxy isononanoate, t-amyl peroxy isopropyl carbonate, and t-amyl peroxy 2-ethylhexyl carbonate. These may be used alone in 1 kind, or 2 or more kinds may be used in combination. In the method (1), a polymerization catalyst having a high hydrogen abstraction ability is preferably used, and an organic peroxide is preferably used as such a polymerization catalyst. The amount of the polymerization catalyst to be used is, for example, preferably 0.01 to 1 part by mass per 100 parts by mass of the monomer component.

The respective amounts of the base polymer (P1) and the monomer component to be used are preferably 0.5 part by mass or more, more preferably 1 part by mass or more, further preferably 3 parts by mass or more, further preferably 50 parts by mass or less, more preferably 30 parts by mass or less, and further preferably 20 parts by mass or less, based on 100 parts by mass of the total of the base polymer (P1) and the monomer component. The monomer component is preferably 50 parts by mass or more, more preferably 70 parts by mass or more, further preferably 80 parts by mass or more, and further preferably 99 parts by mass or less, more preferably 98 parts by mass or less, and further preferably 97 parts by mass or less, based on 100 parts by mass of the total of the base polymer (P1) and the monomer component.

The concentration of the raw material polymer (P1) in the reaction solution is preferably 1% by mass or more, more preferably 3% by mass or more, further preferably 5% by mass or more, and further preferably 50% by mass or less, more preferably 30% by mass or less, further preferably 20% by mass or less. The concentration of the monomer component in the reaction liquid is preferably 5% by mass or more, more preferably 10% by mass or more, and further preferably 80% by mass or less, more preferably 70% by mass or less. The solvent concentration in the reaction solution is preferably 10% by mass or more, more preferably 20% by mass or more, and further preferably 97% by mass or less, more preferably 95% by mass or less, further preferably 90% by mass or less, and further preferably 80% by mass or less. In the polymerization reaction, the base polymer (P1), the monomer component, the polymerization catalyst, the reaction solvent, and the like may be appropriately added.

The polymerization reaction is preferably carried out in an atmosphere or a gas flow of an inert gas such as nitrogen. In order to reduce the residual monomer, an azo compound and a peroxide may be used in combination as a polymerization initiator. The reaction temperature is preferably 50 ℃ to 200 ℃. The reaction time can be appropriately adjusted while observing the degree of progress of the copolymerization reaction and the degree of formation of a gelled product, and is preferably, for example, from 1 hour to 20 hours.

By the above-mentioned polymerization step, a copolymer in which a polymer chain containing a unit derived from a (meth) acrylic monomer is bonded to the polymer chain (a) is obtained. In the polymerization step, when a (meth) acrylic monomer and a monomer having a polymerizable double bond in a ring structure (for example, maleic anhydride or maleimide) are used as monomer components, a copolymer (P) in which a polymer chain (B) having a (meth) acrylic acid unit and a ring structure unit (maleic anhydride structure, maleimide structure) is bonded to a polymer chain (a) is obtained.

On the other hand, when the copolymer (P) having a lactone ring structure, a glutaric acid anhydride structure or a glutarimide structure is obtained as the ring structure unit of the polymer chain (B), the ring structure forming step is preferably performed after the polymerization step. In the ring structure forming step, a ring structure is formed in the main chain of the polymer chain having a (meth) acrylic acid unit formed in the polymerization step. Specifically, a condensation reaction is performed between substituents of adjacent (meth) acrylic acid units of a polymer chain having a (meth) acrylic acid unit formed in the polymerization step, thereby forming a ring structure on the main chain of the polymer chain. The condensation reaction includes esterification, acid anhydride reaction, amidation, imidization, and the like. For example, a glutaric anhydride structure may be formed by anhydrifying 2 carboxylic acid groups of adjacent (meth) acrylic units, or a glutarimide structure may be formed by imidization. In the case where one of the adjacent (meth) acrylic acid units has a protic hydrogen atom-containing group such as a hydroxyl group or an amino group, the lactone ring structure can be formed by condensing the protic hydrogen atom-containing group of the (meth) acrylic acid unit with the carboxylic acid group of the other (meth) acrylic acid unit.

In the ring structure forming step, the condensation reaction of adjacent (meth) acrylic acid units is preferably carried out in the presence of a catalyst (cyclization catalyst). As the cyclization catalyst, at least one selected from acids, bases, and salts thereof can be used. The acid, base and salts thereof may be organic or inorganic, and are not particularly limited. Among them, as the catalyst for the cyclization reaction, an organic phosphorus compound is preferably used. By using an organic phosphorus compound as a cyclization catalyst, the condensation reaction can be efficiently performed, and the coloration of the obtained copolymer (P) can be reduced.

Examples of the organophosphinic compound that can be used as a cyclization catalyst include alkyl (aryl) phosphonous acids and monoesters or diesters thereof; dialkyl (aryl) phosphinic acids and their esters; alkyl (aryl) phosphonic acids and their mono-or diesters; alkyl (aryl) phosphinic acids and their esters; a phosphorous acid mono-, di-, or tri-ester; phosphoric acid monoesters, diesters or triesters such as methyl phosphate, ethyl phosphate, 2-ethylhexyl phosphate, octyl phosphate, isodecyl phosphate, lauryl phosphate, octadecyl phosphate, isostearyl phosphate, phenyl phosphate, dimethyl phosphate, diethyl phosphate, di-2-ethylhexyl phosphate, diisodecyl phosphate, dilauryl phosphate, distearyl phosphate, diisostearyl phosphate, diphenyl phosphate, trimethyl phosphate, triethyl phosphate, triisodecyl phosphate, trilauryl phosphate, tristearyl phosphate, triisostearyl phosphate, and triphenyl phosphate; mono-, di-or tri-alkyl (aryl) phosphines; alkyl (aryl) halophosphines; mono-, di-or tri-alkyl (aryl) phosphine oxides; tetraalkyl (aryl) phosphonium halides and the like. These may be used alone in 1 kind, or 2 or more kinds may be used in combination. Among them, phosphoric acid monoesters and diesters are particularly preferable from the viewpoint of high catalytic activity and low coloring properties. The amount of the cyclization catalyst to be used is, for example, preferably 0.001 to 1 part by mass based on 100 parts by mass of the copolymer obtained in the polymerization step.

The reaction temperature in the ring structure forming step is preferably 50 ℃ to 300 ℃. The reaction time can be appropriately adjusted while observing the degree of progress of the condensation reaction, and is preferably, for example, 5 minutes to 6 hours.

By performing the polymerization step as described above, or the polymerization step and the ring structure forming step, a resin solution containing the copolymer (P) is obtained. The resin solution thus obtained is preferably filtered through a filter to remove foreign matters. Therefore, the method for producing the copolymer (P) preferably further comprises a step of filtering the resin solution obtained in the polymerization step or the ring structure-forming step (filtration step). By performing the filtration step, the amount of foreign materials in the copolymer (P) can be reduced. Therefore, when the copolymer (P) is used as a raw material for an optical film, an optical film having less surface irregularities and defects and high transparency can be easily obtained. In the present invention, since the amount of the gelled product produced in the polymerization step of the copolymer (P) can be suppressed to a low level, the burden on the filter in the filtration step can be reduced, and continuous filtration can be performed for a long period of time. Therefore, the copolymer (P) having a small amount of foreign materials can be obtained with high productivity. The filtering step may be performed continuously after the polymerization step or the ring structure forming step.

As the filter used for filtration, conventionally known filters can be used, and there are no particular limitations thereon, and for example, a leaf disc filter, a candle filter, a wrapped disc filter, a cylindrical filter, and the like can be used. Among them, a leaf disc filter or a candle filter having a large effective filtration area is preferable.

The filtration accuracy (pore size) of the filter may be, for example, usually 15 μm or less. When the copolymer (P) is used for an optical material such as an optical film, the filtration accuracy is preferably 10 μm or less, more preferably 5 μm or less, from the viewpoint of reducing optical defects. The lower limit of the filtration accuracy is not particularly limited, and is, for example, 0.2 μm or more.

In the filtration step, the resin solution containing the copolymer (P) obtained in the polymerization step or the ring structure-forming step may be directly filtered, or may be diluted with a solvent or dispersed in a solvent and filtered. When the copolymer (P) is a solid, it may be melted and filtered by a sintered filter or the like, or may be dissolved or dispersed in a solvent and filtered. The filtration may be carried out under elevated temperature or under elevated pressure.

The solution temperature at the time of supplying the resin solution to the filter for filtration may be appropriately set in accordance with the boiling point of the polymerization solvent, and is preferably not higher than the boiling point of the polymerization solvent, and more preferably not higher than-10 ℃. On the other hand, when the temperature of the resin solution supplied to the filter filtration is too low, the viscosity of the resin solution increases, and the load on the device such as a gear pump may increase, and the temperature of the resin solution supplied to the filter filtration is preferably 50 ℃ or higher, and more preferably 80 ℃ or higher.

The viscosity of the resin solution supplied to the filter is preferably 100 pas or less, more preferably 80 pas or less at 85 ℃. If the viscosity of the resin solution supplied to the filter for filtration is too high, the pressure loss during filtration of the filter increases, and the filter unit may be damaged, and the processing capacity of the filter for filtration may be reduced due to the increase in viscosity. The pressure loss during filtration through the filter is preferably 2.5MPa or less, more preferably in the range of 0.5MPa to 2.0MPa, and still more preferably in the range of 0.5MPa to 1.5 MPa.

[ 2. resin composition ]

The present invention also provides a resin composition containing the copolymer (P) having the polymer chain (a) and the polymer chain (B) explained above. The resin composition of the present invention is excellent in transparency, mechanical strength (e.g., impact strength) and heat resistance in a well-balanced manner, and is reduced in the generation of a gelled product during production. Hereinafter, the resin composition of the present invention is referred to as "resin composition (Q)".

The resin composition (Q) may contain the copolymer (P) as a resin component, or may contain another polymer as a resin component. When the resin composition (Q) contains another polymer, the use of a (meth) acrylic polymer as the other polymer is preferable, whereby the homogeneity of the resin composition (Q) is improved, and the transparency and heat resistance of the resin composition (Q) are easily improved.

The (meth) acrylic polymer may be a polymer having a unit derived from a (meth) acrylic monomer described in the above-mentioned polymer chain (B), and preferably has a unit derived from a (meth) acrylic ester described in the above-mentioned polymer chain (B). The (meth) acrylic polymer may have a unit derived from another unsaturated monomer as described in the above-mentioned polymer chain (B). From the viewpoint of improving the compatibility with the copolymer (P) in the resin composition (Q), the (meth) acrylic polymer more preferably has a unit derived from a (meth) acrylic monomer contained in the polymer chain (B) of the copolymer (P).

The (meth) acrylic polymer is preferably a polymer having a ring structure, and more preferably a polymer having a ring structure in the main chain. The resin composition (Q) contains a (meth) acrylic polymer having a ring structure in the main chain, and thus the heat resistance of the resin composition (Q) can be improved. Preferable examples of the ring structure of the main chain of the (meth) acrylic polymer include a lactone ring structure, a cyclic imide structure (for example, a maleimide structure, a glutarimide structure, etc.), a cyclic acid anhydride structure (for example, a maleic anhydride structure, a glutaric anhydride structure, etc.), and the like, and the details of these ring structures are described above with reference to the ring structure of the polymer chain (B). Among them, the main chain of the (meth) acrylic polymer preferably has a ring structure identical to that of the polymer chain (B) of the copolymer (P).

The (meth) acrylic polymer preferably has a (meth) acrylic acid unit which the polymer chain (B) of the copolymer (P) has, and has a cyclic structure unit which the polymer chain (B) has. When the resin composition (Q) contains such a (meth) acrylic polymer, the compatibility with the copolymer (P) is improved, the transparency and heat resistance of the resin composition (Q) are easily improved, and the preparation of the resin composition (Q) is also easily performed.

The content of the copolymer (P) in 100 mass% of the solid content of the resin composition (Q) is preferably 1 mass% or more, more preferably 2 mass% or more, still more preferably 3 mass% or more, and still more preferably 5 mass% or more, whereby the mechanical strength of the resin composition (Q) can be easily improved. The upper limit of the content of the copolymer (P) in the resin composition (Q) is not particularly limited, and the resin composition (Q) may be composed of only the copolymer (P), and the content of the copolymer (P) in the resin composition (Q) may be 90 mass% or less, or may be 70 mass% or less, 50 mass% or less, 40 mass% or less, or 30 mass% or less. When the resin composition (Q) contains a solvent, the amount of the solid component of the resin composition (Q) refers to the amount of the resin composition (Q) from which the solvent is removed.

The content of the polymer chain (a) in the copolymer (P) is preferably 0.5% by mass or more, more preferably 1% by mass or more, further preferably 3% by mass or more, and further preferably 50% by mass or less, more preferably 30% by mass or less, and further preferably 20% by mass or less, per 100% by mass of the solid content of the resin composition (Q). When the content of the polymer chain (a) in the resin composition (Q) is 0.5% by mass or more, the mechanical strength of the resin composition (Q) is easily improved. When the content of the polymer chain (a) in the resin composition (Q) is 50% by mass or less, the transparency and heat resistance of the resin composition (Q) are easily improved. Content ratio of Polymer chain (A)For example, can use¹H-NMR.

When the resin composition (Q) contains a (meth) acrylic polymer, the content of the (meth) acrylic polymer in 100 mass% of the solid content of the resin composition (Q) is preferably 1 mass% or more, more preferably 20 mass% or more, further preferably 30 mass% or more, further preferably 99 mass% or less, more preferably 95 mass% or less, and further preferably 90 mass% or less.

The total content ratio of the copolymer (P) and the (meth) acrylic polymer in 100 mass% of the solid content of the resin composition (Q) is preferably 50 mass% or more, more preferably 70 mass% or more, further preferably 80 mass% or more, and further preferably 90 mass% or more. The upper limit of the content ratio of the copolymer (P) and the (meth) acrylic polymer in the resin composition (Q) is not particularly limited, and the resin composition (Q) may be substantially composed of only the copolymer (P) and the (meth) acrylic polymer, and for example, the total content ratio of the copolymer (P) and the (meth) acrylic polymer may be 99 mass% or more in 100 mass% of the solid content of the resin composition (Q).

The resin composition (Q) may contain a polymer other than the (meth) acrylic polymer, and examples of such a polymer include olefin polymers such as polyethylene, polypropylene, ethylene-propylene polymer, and poly (4-methyl-1-pentene); halogen-containing polymers such as vinyl chloride and vinyl chloride resins; styrene polymers such as polystyrene, styrene-methyl methacrylate copolymers, styrene-acrylonitrile copolymers, and acrylonitrile-butadiene-styrene copolymers; polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; polyamides such as nylon 6, nylon 66, and nylon 610; a polyacetal; a polycarbonate; polyphenylene ether; polyphenylene sulfide; polyether ether ketone; polysulfones; polyether sulfone; polyether sulfone; a polyamide-imide; and rubbery polymers such as an ABS resin and an ASA resin blended with a polybutadiene rubber and a (meth) acrylic rubber.

The resin composition (Q) may contain various additives within a range not impairing the effects of the present invention. Examples of the additive include antioxidants such as hindered phenols, phosphorus-based antioxidants, and sulfur-based antioxidants; stabilizers such as light-resistant stabilizers, weather-resistant stabilizers, and heat stabilizers; reinforcing materials such as glass fibers and carbon fibers; an ultraviolet absorber; a near infrared ray absorber; flame retardants such as tris (dibromopropyl) phosphate, triallyl phosphate, and antimony oxide; phase difference adjusting agents such as a phase difference improving agent, a phase difference reducing agent, and a phase difference stabilizer; antistatic agents containing anionic, cationic, nonionic surfactants; colorants such as inorganic pigments, organic pigments, and dyes; organic fillers and inorganic fillers; a resin modifier; organic fillers and inorganic fillers. The content ratio of each additive in the resin composition (Q) is preferably in the range of 0 to 5% by mass, more preferably 0 to 2% by mass.

Examples of the ultraviolet absorber include benzophenone compounds, salicylate compounds, benzoate compounds, triazole compounds, and triazine compounds, and known ultraviolet absorbers can be used. Examples of the benzophenone-based compound include 2, 4-dihydroxybenzophenone, 4-n-octyloxy-2-hydroxybenzophenone, and 2,2 '-dihydroxy-4, 4' -dimethoxybenzophenone. Examples of the salicylate-based compound include p-tert-butylphenyl salicylic acid and the like. Examples of the benzoate-based compound include 2, 4-di-t-butylphenyl-3 ', 5 ' -di-t-butyl-4 ' -hydroxybenzoate and the like. Examples of the triazole-based compound include 2,2' -methylenebis [4- (1,1,3, 3-tetramethylbutyl) -6- (2H-benzotriazol-2-yl) phenol ], 2- (3, 5-di-tert-butyl-2-hydroxyphenyl) -5-chlorobenzotriazole, 2- (2H-benzotriazol-2-yl) -p-cresol, 2- (2H-benzotriazol-2-yl) -4, 6-bis (1-methyl-1-phenylethyl) phenol, 2-benzotriazol-2-yl-4, 6-di-tert-butylphenol, 2- [ 5-chloro (2H) -benzotriazol-2-yl ] -4-methyl-6-tert-butylphenol, and mixtures thereof, 2- (2H-benzotriazol-2-yl) -4, 6-tert-butylphenol, 2- (2H-benzotriazol-2-yl) -4- (1,1,3, 3-tetramethylbutyl) phenol and the like. Examples of the triazine compound include a 2-mono (hydroxyphenyl) -1,3, 5-triazine compound, a2, 4-bis (hydroxyphenyl) -1,3, 5-triazine compound, and a2, 4, 6-tris (hydroxyphenyl) -1,3, 5-triazine compound. Examples of commercially available ultraviolet absorbers include "TINUVIN (registered trademark) 1577", "TINUVIN (registered trademark) 460", "TINUVIN (registered trademark) 477" (manufactured by BASF Japan) and "ADK STAB (registered trademark) LA-F70" (manufactured by ADEKA), which are triazine ultraviolet absorbers, and "ADK STAB (registered trademark) LA-31" (manufactured by ADEKA). The ultraviolet absorber may be used alone in 1 kind, or may be used in combination of 2 or more kinds.

As the antioxidant, a compound having a radical trapping function or a peroxide decomposing function can be used, and a known antioxidant can be used. Examples of the antioxidant include hindered phenol-based antioxidants, hindered amine-based antioxidants, phosphorus-based antioxidants, sulfur-based antioxidants, benzotriazole-based antioxidants, benzophenone-based antioxidants, hydroxylamine-based antioxidants, salicylate-based antioxidants, and triazine-based antioxidants. Among these antioxidants, preferred are hindered phenol antioxidants, hindered amine antioxidants, phosphorus antioxidants and sulfur antioxidants. More preferably, hindered phenol type antioxidants, hindered amine type antioxidants and phosphorus type antioxidants are mentioned. The antioxidant may be used in a single amount of 1 kind, or may be used in combination of 2 or more kinds.

Examples of the hindered phenol-based antioxidant include 2, 4-bis [ (laurylthio) methyl ] -o-cresol, 1,3, 5-tris (3, 5-di-t-butyl-4-hydroxybenzyl), 1,3, 5-tris (4-t-butyl-3-hydroxy-2, 6-dimethylbenzyl), and the like.

As the hindered amine-based antioxidant, bis (2,2,6, 6-tetramethyl-4-piperidyl) sebacate, bis (N-methyl-2, 2,6, 6-tetramethyl-4-piperidyl) sebacate, N' -bis (2,2,6, 6-tetramethyl-4-piperidyl) -1, 6-hexamethylenediamine, 2-methyl-2- (2,2,6, 6-tetramethyl-4-piperidyl) amino-N- (2,2,6, 6-tetramethyl-4-piperidyl) propionamide, tetrakis (2,2,6, 6-tetramethyl-4-piperidyl) (1,2,3, 4-butane tetracarboxylic acid ester, poly [ (6- (1,1,3, 3-tetramethylbutyl) imino-1, 3, 5-triazine-2, 4-diyl ((2,2,6, 6-tetramethyl-4-piperidyl) imino) hexamethyl ((2,2,6, 6-tetramethyl-4-piperidyl) imino) ], and the like.

As the phosphorus-based antioxidant, tris (isodecyl) phosphite, tris (tridecyl) phosphite, phenylisooctyl phosphite, phenylisodecyl phosphite, phenyldi (tridecyl) phosphite, diphenylisooctyl phosphite, diphenylisodecyl phosphite, diphenyltridecyl phosphite, triphenyl phosphite, tris (nonylphenyl) phosphite, 4' -isopropylidenediphenol alkyl phosphite, trisnonylphenyl phosphite, tris (dinonylphenyl) phosphite, and other oligomeric and polymeric compounds having a phosphite structure may be used.

Examples of the sulfur-based antioxidant include 2, 2-thio-divinylbis [3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate ], 2, 4-bis [ (octylthio) methyl ] -o-cresol, and 2, 4-bis [ (laurylthio) methyl ] -o-cresol. Other oligomeric and polymeric compounds having a thioether structure may also be used.

The weight average molecular weight of the resin composition (Q) is preferably 0.2 ten thousand or more, more preferably 0.5 ten thousand or more, further preferably 3 ten thousand or more, further preferably 5 ten thousand or more, particularly preferably 7 ten thousand or more, further preferably 100 ten thousand or less, more preferably 50 ten thousand or less, further preferably 30 ten thousand or less, further preferably 20 ten thousand or less. When the weight average molecular weight of the resin composition (Q) is within such a range, the molding processability of the resin composition (Q) is improved and the strength of the obtained molded article is also easily improved. The weight average molecular weight of the resin composition (Q) is a value in terms of polystyrene measured by gel permeation chromatography, and when the resin composition (Q) contains the copolymer (P) and the (meth) acrylic polymer, the weight average molecular weight of the resin composition (Q) is the weight average molecular weight of the whole of these plural polymers.

The weight average molecular weight of the resin composition (Q) is preferably 1.1 times or more, more preferably 1.2 times or more, further preferably 1.3 times or more, further preferably 20 times or less, more preferably 12 times or less, further preferably 10 times or less, further preferably 7 times or less, and particularly preferably 5 times or less, of the weight average molecular weight of the polymer chain (a) of the copolymer (P). This makes it possible to easily impart the resin composition (Q) with well-balanced properties such as transparency, mechanical strength, and heat resistance.

The refractive index of the resin composition (Q) is preferably a value close to the refractive index of the polymer chain (a) of the copolymer (P), whereby the transparency of the resin composition (Q) can be easily ensured. Specifically, the difference between the refractive index of the resin composition (Q) and the refractive index of the polymer chain (a) of the copolymer (P) is preferably less than 0.1, more preferably 0.05 or less, and still more preferably 0.02 or less. From the same viewpoint, the refractive index of the resin composition (Q) is preferably a value close to the refractive index of the copolymer (P), and specifically, the difference between the refractive index of the resin composition (Q) and the refractive index of the copolymer (P) is preferably less than 0.1, more preferably 0.05 or less, and further preferably 0.02 or less.

The total light transmittance of the resin composition (Q) in the case of forming an unstretched film having a thickness of 160 μm is preferably 70% or more, more preferably 80% or more, and still more preferably 90% or more. The haze is preferably 5.0% or less, more preferably 3.0% or less, and still more preferably 1.0% or less. The internal haze is preferably 5.0% or less, more preferably 3.0% or less, further preferably 2.0% or less, and further preferably 1.0% or less per 100 μm thickness when an unstretched film is produced.

The resin composition (Q) exhibits a sea-island structure when formed into an unstretched film having a thickness of 160 μm, and the island size in the structure is preferably 500nm or less, more preferably 400nm or less, and still more preferably 350nm or less. Thus, when a film is formed from the resin composition (Q), a film having high transparency can be easily obtained. The lower limit of the island size of the sea-island structure is not particularly limited, and may be, for example, 10nm or more, or 50nm or more. The sea-island structure of the unstretched film formed from the resin composition (Q) was observed by a scanning electron microscope (STEM), and the specific measurement method was as described in examples.

The resin composition (Q) preferably has a glass transition temperature of 100 ℃ or higher and less than 100 ℃, respectively. The glass transition temperature of 100 ℃ or higher is referred to as "glass transition temperature on the high temperature side", and the glass transition temperature of less than 100 ℃ is referred to as "glass transition temperature on the low temperature side". The resin composition (Q) may have a plurality of glass transition temperatures on the high temperature side or a plurality of glass transition temperatures on the low temperature side. The resin composition (Q) has a glass transition temperature on the high temperature side, so that the heat resistance of the resin composition (Q) is improved, and the resin composition (Q) does not soften even at high temperatures when formed into a film or the like, thereby improving the molding processability. The resin composition (Q) has a glass transition temperature on the low temperature side, and thus the mechanical strength and impact resistance of the resin composition (Q) can be improved. The glass transition temperature of the resin composition (Q) on the high temperature side is preferably 113 ℃ or higher, more preferably 116 ℃ or higher, and still more preferably 120 ℃ or higher, and from the viewpoint of improving the processability of the resin composition (Q), it is preferably less than 300 ℃, more preferably less than 200 ℃, and still more preferably less than 180 ℃. The glass transition temperature of the resin composition (Q) on the low temperature side is preferably-100 ℃ or higher, more preferably-90 ℃ or higher, further preferably-80 ℃ or higher, and further preferably less than 50 ℃, more preferably less than 30 ℃, and further preferably less than 10 ℃.

The insoluble content of the resin composition (Q) in chloroform is preferably 10% by mass or less, more preferably 8% by mass or less, and still more preferably 5% by mass or less. Since the copolymer (P) contained in the resin composition (Q) does not substantially contain a crosslinked structure, it can be contained in a small amount, and therefore, the ratio of insoluble components in chloroform of the resin composition (Q) can be reduced. Therefore, the amount of the foreign material contained in the resin composition (Q) is small, and for example, when an optical film is formed from the resin composition (Q), a film having less surface irregularities and defects and high transparency can be easily obtained. In addition, when foreign matter is removed from the resin composition, the burden imposed on the foreign matter removal filter is reduced, and the production efficiency is improved.

On the other hand, for example, in the elastic organic fine particles having a core-shell structure disclosed in jp 2008-a 242421, the organic fine particles are insoluble in chloroform because they are graft copolymers having a crosslinked structure. Therefore, when a copolymer having such a crosslinked structure is used as a raw material for an optical film which is required to have high quality, it is not preferable because it causes foreign matter and defects in the film and causes appearance defects such as surface unevenness and haze when the film is stretched. In addition, when foreign matter is removed from the resin composition before film formation, the organic fine particles impose a high load on the foreign matter removal filter, resulting in a decrease in productivity.

The insoluble content of the resin composition in chloroform was determined by the method described in examples. Specifically, 1g of the resin composition was added to 20g of chloroform, and the mixture was filtered through a Teflon (registered trademark) membrane filter having a pore size of 0.5 μm, and the amount of insoluble matter trapped by the membrane filter was measured to determine the ratio of the insoluble matter in chloroform.

The amount of foaming generated when the resin composition (Q) is heated at 290 ℃ for 20 minutes is preferably 20 pieces/g or less, more preferably 10 pieces/g or less, and still more preferably 5 pieces/g or less. This improves the appearance of a molded article (e.g., a film) obtained by thermoforming the resin composition (Q). The amount of foaming was measured by filling the dried resin composition in a cylinder having a melt index using a melt index meter specified in JIS K7210, holding the resin composition at 290 ℃ for 20 minutes, extruding the resin composition into a bar shape, and counting the number of bubbles formed between the upper and lower markings of the bar, and expressing the number of bubbles per 1g of the resin composition.

The melt viscosity of the resin composition (Q) at 270 ℃ and 100(/ sec) measured according to JIS K7199 (1999) is preferably 50 pas or more, more preferably 100 pas or more, further preferably 5000 pas or less, and more preferably 1000 pas or less. When the melt viscosity of the resin composition (Q) is in such a range, the molding processability of the resin composition (Q) is improved, fish eyes, parting lines, and the like are less likely to occur in the molded article, and the molded article has a good appearance.

The resin composition (Q) has a breaking energy of preferably 20mJ or more, more preferably 24mJ or more, and still more preferably 28mJ or more, when it is formed into an unstretched film having a thickness of 160 μm. Thus, when a film is formed from the resin composition (Q), a film having high mechanical strength can be easily obtained. The destruction can be determined by the method described in examples.

The trouser tear strength of the resin composition (Q) when formed into a stretched film having a thickness of 40 μm is preferably 15mJ or more, more preferably 18mJ or more, and still more preferably 22mJ or more. Thus, when a film is formed from the resin composition (Q), a film having high tear strength can be easily obtained. The trouser tear strength was determined by the method described in examples.

The number of folding endurance tests measured by the MIT folding endurance test when the resin composition (Q) is formed into an elongated thin film having a thickness of 40 μm is preferably 1000 or more, more preferably 1200 or more, and still more preferably 1350 or more. Thus, when a film is formed from the resin composition (Q), a film which is less likely to be broken can be easily obtained. The MIT folding endurance test was performed by the method described in the examples.

The method for producing the resin composition (Q) is not particularly limited, and when the copolymer (P) is produced by polymerization, the (meth) acrylic polymer can be produced by simple co-polymerization. In the above-described process for producing the copolymer (P), the copolymer (P) is produced and the (meth) acrylic polymer corresponding to the polymer chain (B) of the copolymer (P) is also produced, and in this case, the copolymer (P) and the (meth) acrylic polymer are not separated, whereby the resin composition (Q) containing the copolymer (P) and the (meth) acrylic polymer can be obtained. In the method for producing the resin composition (Q) in this case, the copolymer (P) and the (meth) acrylic polymer having a ring structure in the main chain are obtained by the polymerization step or the polymerization step and the ring structure forming step described in the method for producing the copolymer (P).

The method for producing the resin composition (Q) is not limited to the above-mentioned method, and the copolymer (P) may be isolated and mixed with other polymers as the resin composition (Q). In the above-mentioned method for producing the copolymer (P), after the graft copolymerization with the copolymer (P1) is completed, a polymerization reaction may be further carried out by adding another monomer to obtain the resin composition (Q). Alternatively, as the resin composition (Q), other polymers (for example, other (meth) acrylic polymers) may be further added to the mixture of the copolymer (P) and the (meth) acrylic polymer obtained by the above-mentioned method for producing the copolymer (P). When other polymers are added and mixed, melt kneading may be performed, and in this case, for example, a general apparatus such as a kneader or a multi-shaft extruder may be used.

In the method for producing the resin composition (Q), the filtration step described above may be performed after the polymerization step or the ring structure formation step. By performing the filtration step, the amount of foreign materials in the resin composition (Q) can be reduced, and the resin composition (Q) can be suitably used for applications in which a high-quality optical film or the like is desired. For details of the filtration step, reference is made to the description of the filtration step in the above-mentioned method for producing the copolymer (P).

[ 3. Molding of copolymer and resin composition ]

The copolymer (P) and the resin composition (Q) may be used in a liquid state or as a cured product. In the latter case, the copolymer (P) and the resin composition (Q) are heated and melted to be molded into an arbitrary shape, whereby a molded article can be produced. The shape of the molded article may be appropriately set according to the application, and examples thereof include a plate shape, a sheet shape, a granular shape, a powder shape, a block shape, a particle aggregate shape, a spherical shape, an ellipsoidal shape, a lenticular shape, a cubic shape, a columnar shape, a rod shape, a cone shape, a cylindrical shape, a needle shape, a fibrous shape, a hollow filament shape, a porous shape, and the like. The molded article of the copolymer (P) and the resin composition (Q) may be injection molding, extrusion molding, vacuum molding, compression molding, blow molding or the like, and in this case, for example, a powder having a particle diameter of 1 μm to 1000 μm, a cylindrical or spherical particle having a major axis of about 1mm to 10mm, or a mixture thereof is preferable.

The copolymer (P) and the resin composition (Q) may be formed into a film. As a method for forming a film, known methods such as a solution casting method (solution casting method), a melt extrusion method, a rolling method, a compression molding method, and the like can be used. Among them, the solution casting method and the melt extrusion method are preferable.

Examples of the solvent used in the solution casting method include chlorine-based aliphatic hydrocarbons such as chloroform and methylene chloride; aromatic hydrocarbons such as toluene, xylene, and benzene; alcohols such as methanol, ethanol, isopropanol, n-butanol, and 2-butanol; cellosolves such as methyl cellosolve, ethyl cellosolve, and butyl cellosolve; ethers such as diethyl ether, dioxane and tetrahydrofuran; ketones such as acetone and cyclohexanone: esters such as ethyl acetate, propyl acetate, and butyl acetate; dimethylformamide; dimethyl sulfoxide, and the like. These may be used alone in 1 kind, or 2 or more kinds may be used in combination.

Examples of the apparatus for performing the solution casting method include a drum casting machine, a belt casting machine, and a spin coater.

Examples of the melt extrusion method include a T-die method and an inflation method. The temperature (molding temperature) at which the film is melt-extruded is preferably 150 ℃ or higher, more preferably 200 ℃ or higher, and further preferably 350 ℃ or lower, more preferably 300 ℃ or lower.

In the T-die method, a film extruded from an extruder having a T-die attached to a tip end thereof is wound around a roll to obtain a film wound around the roll. At this time, by controlling the temperature and speed of winding, stretching (uniaxial stretching) can be applied in the extrusion direction of the film.

The melt extrusion molding preferably uses an extruder. The extruder preferably has a cylinder and a screw provided in the cylinder, and is provided with a heating means. The extruder is classified into a single-screw extruder, a twin-screw extruder, a multi-screw extruder, and the like according to the number of screws, and any one of the extruders may be used. In order to obtain a resin composition which is sufficiently plasticized and has a good kneaded state, the L/D value of the extruder (L is the length of the cylinder of the extruder and D is the inner diameter of the cylinder) is preferably 10 or more, more preferably 15 or more, further preferably 20 or more, and further preferably 100 or less, more preferably 80 or less, and further preferably 60 or less. When the L/D value is less than 10, the resin composition may not be sufficiently plasticized, and a good kneaded state may not be obtained. When the L/D value exceeds 100, shear heat is excessively applied to the resin composition, and the components contained in the resin composition are easily thermally decomposed.

The set temperature (heating temperature) of the barrel of the extruder is preferably 200 ℃ or higher, more preferably 250 ℃ or higher, and further preferably 350 ℃ or lower, more preferably 320 ℃ or lower. When the set temperature is less than 200 ℃, the melt viscosity of the resin composition becomes too high, and the productivity of the film may be lowered. When the set temperature exceeds 350 ℃, the components contained in the resin composition are easily thermally decomposed.

The extruder preferably has 1 or more open vent. By using such an extruder, decomposed gas can be sucked from the open-ventilation part, and the amount of residual volatile components in the obtained film can be reduced. In order to suck the decomposition gas from the open-ventilation part, the open-ventilation part may be in a reduced pressure state, and the degree of pressure reduction in this case is preferably 1.3hPa or more, more preferably 13.3hPa or more, further preferably 931hPa or less, and more preferably 798hPa or less, as the pressure (absolute pressure) of the open-ventilation part. When the pressure in the open-ventilation part is higher than 931hPa, volatile components or monomer components generated by decomposition of the polymer contained in the resin composition tend to remain on the obtained film. On the other hand, it is industrially difficult to maintain the pressure in the open-ventilation part at less than 1.3 hPa.

In the melt extrusion molding, it is preferable that the copolymer (P) or the resin composition (Q) in a molten state is filtered through a polymer filter to remove foreign matters contained in the copolymer (P) or the resin composition (Q). Thus, when an optical film is formed from the copolymer (P) or the resin composition (Q), the amount of optical defects and appearance defects in the finally obtained optical film can be reduced.

The temperature for melt extrusion molding is, for example, preferably 200 ℃ or higher, more preferably 250 ℃ or higher, and further preferably 350 ℃ or lower, more preferably 320 ℃ or lower. When the temperature of the melt extrusion molding is 200 ℃ or more, the viscosity of the copolymer (P) and the resin composition (Q) is lowered, and the residence time in the polymer filter can be shortened. When the temperature of the melt extrusion molding is 350 ℃ or lower, for example, in the continuous molding of a film, defects such as through holes, flow patterns, flow streaks, etc. are not easily formed in the film, and a film having a good appearance is easily obtained.

The structure of the polymer filter is not particularly limited. For example, a polymer filter having a plurality of leaf disk type filters mounted in a housing is preferably used. As the filter medium of the leaf disk filter, any one type of filter medium obtained by sintering a metal fiber nonwoven fabric, filter medium obtained by sintering metal powder, filter medium obtained by laminating a plurality of metal meshes, hybrid filter medium obtained by combining these, or the like can be used. Among them, a filter medium obtained by sintering a metal fiber nonwoven fabric is preferably used.

The filtration accuracy (pore size) of the polymer filter is not particularly limited. The filtration accuracy is usually 15 μm or less, preferably 10 μm or less, and more preferably 5 μm or less, in consideration of the size of the foreign matter to be removed. The lower limit of the filtration accuracy is not particularly limited, but is preferably 1 μm or more in view of prolonging the residence time of the copolymer (P) or the resin composition (Q) in the polymer filter, thermally deteriorating the copolymer (P) or the resin composition (Q), or reducing the productivity of the film.

The shape of the polymer filter is not particularly limited. Examples of the type of the polymer filter include an internal flow type having a plurality of resin flow ports and a flow path for resin in a center rod, an external flow type having a cross section in contact with the inner peripheral surface of a leaf disc filter at a plurality of apexes or surfaces and a flow path for resin on the outer surface of a center rod. Among them, since the residence sites of the resin are small, it is preferable to use an outflow type polymer filter.

The residence time of the copolymer (P) or the resin composition (Q) in the polymer filter is preferably 20 minutes or less, more preferably 10 minutes or less, and still more preferably 5 minutes or less. In the melt filtration, the inlet pressure of the polymer filter and the outlet pressure of the filter are, for example, 3MPa to 15MPa and 0.3MPa to 10MPa, respectively. The pressure loss (the pressure difference between the inlet pressure and the outlet pressure of the polymer filter) in the melt filtration is preferably 1MPa to 15 MPa. When the pressure loss is 1MPa or less, the copolymer (P) and the resin composition (Q) are likely to deviate from the flow path passing through the polymer filter. The deviation of the flow path is a cause of deterioration in quality of the obtained thin film. When the pressure loss exceeds 15MPa, the polymer filter is easily broken.

When the copolymer (P) or the resin composition (Q) is melt-filtered, it is preferable to stabilize the pressure in the polymer filter by providing a gear pump between the extruder and the polymer filter. The melt filtration by the polymer filter can be carried out at any timing other than the time of melt extrusion molding.

When the film is formed by melt extrusion, it may be stretched to form an elongated film. By stretching, the mechanical strength of the film can be further improved. As the stretching method for obtaining the stretched film, a conventionally known stretching method can be applied. For example, uniaxial stretching such as free width uniaxial stretching or fixed width uniaxial stretching; biaxial stretching such as sequential biaxial stretching and simultaneous biaxial stretching; a laminate is formed by bonding a shrinkable film to one or both surfaces of a film during stretching, and the laminate is subjected to a heat stretching treatment to apply a shrinking force in the film stretching direction and the direction perpendicular thereto, thereby obtaining stretching of a birefringent film in which molecules oriented in the stretching direction and the thickness direction are mixed. From the viewpoint of improving mechanical strength such as folding resistance of the film, biaxial stretching is preferably used. Further, from the viewpoint of improving mechanical strength such as folding resistance in two directions perpendicular to each other in the film plane, simultaneous biaxial stretching is preferably used. Examples of the two perpendicular directions in the plane include a direction parallel to the slow axis in the film plane and a direction perpendicular to the slow axis in the film plane. The stretching conditions such as the stretching ratio, the stretching temperature, and the stretching speed may be appropriately set according to the desired mechanical strength and the phase difference value, and are not particularly limited.

Examples of the stretching apparatus include a roll stretcher, a tenter stretcher, a tensile testing machine as a small-sized experimental stretching apparatus, a single-shaft stretcher, a sequential biaxial stretcher, and a simultaneous biaxial stretcher, and any of these apparatuses can be used.

The elongation temperature is preferably set to a temperature near the maximum glass transition temperature of the copolymer (P) or the resin composition (Q). Specifically, it is preferably carried out in the range of-30 ℃ maximum glass transition temperature to +50 ℃, more preferably-20 ℃ maximum glass transition temperature to +45 ℃, and still more preferably-10 ℃ maximum glass transition temperature to +40 ℃. When the glass transition temperature is lower than the maximum glass transition temperature of-30 ℃, a sufficient draw ratio may not be obtained. When the temperature is higher than the maximum glass transition temperature +50 ℃, the flow (flow) of the resin is caused and it is difficult to stably conduct elongation.

The draw ratio defined by the area ratio is preferably in the range of 1.1 to 30 times, more preferably in the range of 1.2 to 20 times, and still more preferably in the range of 1.3 to 10 times. When the fiber is stretched in a certain direction, the stretching magnification in the one direction is preferably in the range of 1.05 to 10 times, more preferably in the range of 1.1 to 7 times, and still more preferably in the range of 1.2 to 5 times. When the draw ratio is set within such a range, effects such as improvement in mechanical strength of the film can be more easily obtained with drawing.

The elongation rate (in one direction) is preferably in the range of 10 to 20,000%/min, more preferably in the range of 100-. If the ratio is less than 10%/min, it takes time to obtain a sufficient draw ratio, and the production cost tends to increase. Above 20,000%/minute, breakage of the stretched film or the like may be caused.

When the drawn film is applied to an optical film, it is preferable to perform heat treatment (annealing) as necessary after drawing in order to stabilize the optical properties and mechanical properties of the optical film.

[ 4. optical film ]

The film formed from the copolymer (P) or the resin composition (Q) is excellent in transparency and therefore can be suitably used as an optical film. The optical film thus obtained was excellent in both mechanical strength and heat resistance. The optical film may be an extended film or an unextended film. Examples of the optical film include an optical protective film (specifically, a protective film for a substrate of various optical disks (VD, CD, DVD, MD, LD, etc.)), a polarizer protective film used for a polarizing plate of an image display device such as a liquid crystal display, a viewing angle compensation film, a light diffusion film, a reflection film, an antireflection film, an antiglare film, a brightness enhancement film, a conductive film for a touch panel, a retardation film, and the like.

The thickness of the optical film is preferably 5 μm or more, more preferably 15 μm or more, and further preferably 20 μm or more, from the viewpoint of enhancing the strength of the optical film. On the other hand, from the viewpoint of thinning of the optical film, the thickness of the optical film is preferably 350 μm or less, more preferably 200 μm or less, and further preferably 150 μm or less. The thickness of the optical film can be measured using, for example, a digital micrometer manufactured by Sanfeng corporation.

The optical film preferably has a high light transmittance, for example, a total light transmittance of preferably 70% or more, more preferably 80% or more, and further preferably 90% or more.

The haze of the optical film is preferably 5.0% or less, more preferably 3.0% or less, and still more preferably 1.0% or less, from the viewpoint of improving transparency. The internal haze is preferably 5.0% or less, more preferably 3.0% or less, still more preferably 2.0% or less, and still more preferably 1.0% or less.

Preferably, the optical film has an in-plane retardation Re of 0nm to 1000nm with respect to light having a wavelength of 589nm, and a retardation Rth of-1000 nm to 1000nm in a thickness direction of the light. More preferably, Re is 0nm to 100nm, Rth is-100 nm to 100 nm; further preferably, Re is 0nm to 50nm, and Rth is-30 nm to 30 nm; particularly preferably, Re is 0nm to 10nm, and Rth is-10 nm to 10 nm. The optical film exhibiting such an in-plane retardation Re and a retardation Rth in the thickness direction has good viewing angle characteristics and contrast characteristics, and can be suitably used for an image display device including a liquid crystal display. In addition, the in-plane retardation Re is defined by Re ═ nx-ny × d, the retardation Rth in the thickness direction is defined by Rth ═ d { (nx + ny)/2-nz }, nx represents the refractive index in the slow axis direction (the direction in which the refractive index is the largest in the film plane) in the film plane, ny represents the refractive index in the direction perpendicular to nx in the film plane, nz represents the refractive index in the film thickness direction, and d represents the thickness (nm) of the film.

The optical film may be formed of only the copolymer (P) or the resin composition (Q), or may be formed by laminating another optical material on the film. Optical properties can be further imparted to the optical film by laminating other optical materials. Examples of the other optical materials include a polarizing plate, a polycarbonate stretched alignment film, and a cyclic polyolefin stretched alignment film.

Various functional coatings may be provided on the surface of the optical film as required. Examples of the functional coating layer include an antistatic layer, an adhesive layer, an easy-to-adhere layer, an anti-staining layer such as an anti-glare (non-glare) layer or a photocatalyst layer, an antireflection layer, a hard coat layer, an ultraviolet shielding layer, a heat ray shielding layer, an electromagnetic wave shielding layer, and a gas barrier layer. Further, an optical adjustment layer for appropriately adjusting the transmittance or reflectance of incident light may be provided on the surface of the optical film.

The optical film of the present invention is particularly preferably used as a polarizer protective film. The polarizer protective film is not particularly limited except for containing the copolymer (P). When the optical film is applied to the polarizer protective film, the polarizing plate may be configured by providing the optical film (polarizer protective film) on one surface or both surfaces of the polarizer. The optical film (polarizer protective film) is preferably fixed to the polarizer directly or indirectly via another layer with an adhesive or a sticking agent.

The type of polarizer is not particularly limited, and examples thereof include polarizers obtained by dyeing and stretching a polyvinyl alcohol film; a polyolefin polarizer of dehydrated polyvinyl alcohol or dehydrochlorinated polyvinyl chloride or the like; reflective polarizers using multilayer laminates or cholesteric liquid crystals; polarizers made of thin crystalline films, and the like. Examples of the structure of the polarizing plate include: a polarizer is obtained by dyeing polyvinyl alcohol with a dichroic substance such as iodine or a dichroic dye and uniaxially stretching the dyed polyvinyl alcohol, and a polarizer protective film (optical film) is provided on one or both surfaces of the polarizer.

The optical film can also be used as a transparent conductive film by forming a transparent conductive layer on the surface. As the material constituting the transparent conductive layer, any material conventionally used as a conductive material in this field can be used, and specific examples thereof include: an organic conductive compound; an organic conductive polymer; metal oxides such as indium oxide, tin oxide, zinc oxide, indium-tin oxide (ITO), antimony-tin oxide (ATO), zinc-aluminum oxide, indium-zinc oxide (IZO); metals such as gold, silver, copper, palladium, aluminum, and the like.

The optical film (e.g., polarizer protective film, transparent conductive film) of the present invention can be preferably applied to an image display device. Examples of the image display device include a liquid crystal display device. For example, in the case of a liquid crystal display device, the image display unit may be configured to: has a liquid crystal cell, a polarizing plate, a backlight, etc., and has the optical film of the present invention. Examples of image display devices other than liquid crystal display devices include Electroluminescent (EL) display panels, Plasma Display Panels (PDPs), Field Emission Displays (FEDs), QLEDs, and micro LEDs.

The present application claims the benefit of priority based on japanese patent application No. 2017-004468, filed on 13/1/2017. The entire contents of the specification of Japanese patent application No. 2017-004468, filed on 13/1/2017, are incorporated herein by reference.

Examples

The present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited to the examples and comparative examples. In the following, unless otherwise specified, "part" means "part by mass" and "%" means "% by mass".

(1) Analytical method

(1-1) weight average molecular weight (Mw) and number average molecular weight (Mn)

The weight average molecular weight and the number average molecular weight were determined by polystyrene conversion using Gel Permeation Chromatography (GPC). The apparatus and measurement conditions used for the measurement were as follows.

-an assay system: GPC System HLC-8220 manufactured by Tosoh corporation

Determination of side pillar Structure

Protection of the column: TSKguardcolumn SuperHZ-L, manufactured by Tosoh corporation

Separating the column: TSKgel SuperHZM-M2 series connection made by Tosoh

Reference jamb construction

Reference column: TSKgel SuperH-RC, manufactured by Tosoh

-developing solvent: chloroform (and pure Chinese medicine, special level)

-solvent flow rate: 0.6 mL/min

-standard sample: TSK Standard polystyrene (PS-oligomer kit, made by Tosoh Co., Ltd.)

(1-2) glass transition temperature (Tg)

The glass transition temperature was determined in accordance with JIS K7121 (2012). Specifically, about 10mg of the sample was heated from room temperature to 300 ℃ (heating rate 20 ℃/min) in a nitrogen atmosphere using a differential scanning calorimeter (Thermo plus EVO DSC-8230, physical product) to obtain a DSC curve, and the DSC curve was evaluated by the origin method. Alpha-alumina was used as reference. The glass transition temperature of less than 40 ℃ was evaluated by the origin method from a DSC curve obtained by heating a sample from-100 ℃ to 60 ℃ (heating rate 10 ℃/min) in a nitrogen atmosphere using a differential scanning calorimeter (from Netch corporation, DSC-3500). An empty container was used as a reference.

(1-3) monomer reaction Rate

The monomer reaction rate (conversion rate) was determined by measuring the amount of residual monomer in the polymerization reaction solution using a gas chromatograph (GC-2014, manufactured by Shimadzu corporation).

(1-4) evaluation of gelation (filtration test)

The gelation evaluation of the resin composition was performed by a filter filtration test. A0.1% by mass chloroform solution of the resin composition was filtered using a plastic syringe having a filter (manufactured by GL Science, chromatographic disk 13N, pore diameter 0.45 μm) attached to the tip thereof, and a total volume of 2mL was evaluated as "O", and a filter in the middle was clogged, and a total volume of 2mL was evaluated as "X".

(1-5) chloroform-insoluble fraction

The resin composition (1 g) was added to chloroform (20 g), and the mixture was filtered through a membrane filter (manufactured by ADVANTEC, T050A047A) having a pore size of 0.5. mu.m, and the filtered membrane filter was dried. According to the mass M of the membrane filter before filtration₀(g) Mass M of the filtered and dried membrane filter₁(g) Is represented by the following formulaChloroform-insoluble content of the resin composition was determined: chloroform-insoluble matter (% by mass) ═ M₁-M₀)/1×100。

(1-6) breaking energy (falling ball test)

The destruction can be determined as follows. First, the resin composition was formed into a film (non-stretched film) having a thickness of 160 μm by hot pressing. Next, a test of dropping a ball having a mass of 0.0054kg from a certain height was performed 10 times on the film, and an average value of the height (breaking height) when the film was broken was obtained. Specifically, the height was set to several stages, and when the ball was dropped from a low height in order, the height of the film crack was obtained, and the height of 10 film cracks was obtained by repeating the steps 10 times, and the average value was obtained as the fracture height. Whether or not the film was broken was judged by dropping a ball on the film and then visually checking whether or not the film was deformed. When deformation was observed, the film was considered to be broken. The destruction energy (E) was determined by the following formula: energy of failure e (mj) is the mass (kg) of the sphere x mean value of failure height (mm) x 9.8 (m/s)²)。

(1-7) Total light transmittance

A film (non-stretched film) having a thickness of 160 μm was obtained by hot-pressing the resin composition to form a film, and the total light transmittance was measured by a haze meter (NDH-5000, manufactured by Nippon Denshoku industries Co., Ltd.).

(1-8) internal haze

The resin composition was hot-pressed at 250 ℃ to prepare a film (non-stretched film) having a thickness of about 160 μm. 1,2,3, 4-tetrahydronaphthalene (tetrahydronaphthalene) was filled in a quartz cell, and the film thus prepared was immersed in the quartz cell, and the haze was measured by a haze meter (NDH-5000, manufactured by Nippon Denshoku industries Co., Ltd.), and the internal haze per 100 μm of thickness was calculated by the following equation: internal haze (%) per 100 μm thickness was obtained as measured value (%) × (100 μm/thickness of film (μm)). Further, the measurement was performed using 3 films, and the internal haze per 100 μm thickness was calculated from the average value thereof.

(1-9) Dispersion State (observation of sea island Structure size by STEM)

A film (non-stretched film) having a thickness of 160 μm and prepared by hot press molding the resin composition at 250 ℃ was observed for a dispersion state (sea-island structure) of the film by phase separation by a scanning electron microscope (FE-SEM S-4800, manufactured by Hitachi High-Technologies Co., Ltd.). The measurement conditions were: acceleration voltage 20kV, emission current 5 μ a or 10 μ a, w.d. ═ 8 mm. The island size was calculated by measuring the maximum length of any 10 island portions and calculating the average value thereof.

(1-10) MIT folding endurance test (folding endurance)

The resin composition was hot-press molded at 250 ℃ to obtain an unstretched film having a thickness of 160 μm. The obtained undrawn film was cut into a size of 96mm × 96mm, subjected to successive biaxial stretching (X-6S, manufactured by Toyo Seiki Seisaku-Sho Ltd.) at a temperature of Tg +24 ℃ at a stretching speed of 240 mm/min so that the stretching ratio was 2 times in the longitudinal direction (MD direction) and in the transverse direction (TD direction), respectively, and cooled to obtain a drawn film having a thickness of 40 μm. The obtained stretched film was cut into pieces of 90mm × 15mm, and the number of times of the MIT folding endurance test was measured in accordance with JIS P8115 (2001) by using an MIT folding endurance TESTER (manufactured by TESTER INDUSTRIAL Co., Ltd., BE-201) under an atmosphere of 23 ℃ and 50% relative humidity under a load of 200 g.

(1-11) trouser tear Strength (tear Strength)

The trouser tear strength was determined according to JIS K7128-1 (1998). Specifically, the stretched film obtained as described in the above (1-10) was cut into a size of 120mm × 30mm, allowed to stand at a temperature of 23 ℃ under an atmosphere of a relative humidity of 50% for 1 hour or more, and then tested at a test speed of 200 mm/min using an Autograph (AGS-X, manufactured by Shimadzu corporation), and the average value of the tear strength excluding 20mm at the start of tearing and 35mm other than 5mm at the end of tearing was calculated, and the average value of 5 samples was used as the measurement result.

(1-12) phase difference

The stretched film obtained as described in the above (1-10) was measured for an in-plane retardation Re and a thickness direction retardation Rth at an incident angle of 40 ℃ with respect to a wavelength of 590nm using a fully automatic birefringence meter (KOBRA-WR, manufactured by Oji scientific instruments). The in-plane retardation Re and the thickness direction retardation Rth were determined from the following equation, where nx is the refractive index of the film in the slow axis direction, ny is the refractive index of the film in the fast axis direction, nz is the refractive index of the film in the thickness direction, and d is the thickness of the film.

In-plane retardation Re ═ nx-ny) × d

Thickness direction retardation Rth ═ [ (nx + ny)/2-nz ] × d

(2) Preparation of resin composition

(2-1) example 1: preparation of resin composition (A-1)

To a reactor equipped with a stirrer, a temperature sensor, a cooling tube and a nitrogen gas inlet tube, 3 parts of an esterification product of a maleic anhydride adduct of polyisoprene and 2-hydroxyethyl methacrylate (UC-102M, manufactured by KURARAY Co., Ltd.), 26 parts of Methyl Methacrylate (MMA), 1 part of methyl 2- (hydroxymethyl) acrylate (MHMA) and 50 parts of toluene as a polymerization solvent were added, and the temperature was raised to 105 ℃ while passing nitrogen gas therethrough. Then, 0.09 part of t-amyl peroxy isononanoate (LUPEROX (registered trademark) 570, manufactured by ARKEMA GYFI.) as an initiator was added thereto, and solution polymerization was carried out at 105 ℃ and 110 ℃ for 30 minutes. Herein, 0.01 part of octadecyl phosphate was added as a cyclization catalyst, and the reaction was carried out for 10 minutes. Thus, a resin composition containing a lactone ring-containing (meth) acrylic polymer and a graft copolymer in which the polymer chain is grafted to a polyisoprene chain was obtained. The reaction rate of MMA calculated from the amount of residual monomer in the polymerization reaction liquid was 16% and the reaction rate of MHMA was 10%. The composition ratio of the (meth) acrylic polymer chain bonded to the polyisoprene chain, calculated from the reaction rate, to the (meth) acrylic polymer (mass basis) was MMA: MHMA 97.7: 2.3, the content of the unit derived from (meth) acrylate was 96.2% by mass, and the content of the cyclic structure unit was 3.5% by mass. When a part of the reaction solution is taken out to carry out a filtration experiment, filtration can be preferably carried out.

Then, 50 parts of Methyl Ethyl Ketone (MEK) was added to the obtained reaction solution to dilute the solution, and the diluted solution was filtered through a PTFE (polytetrafluoroethylene) filter having a pore size of 10 μm, and then slowly added to a large amount of methanol while stirring the solution. The white solid precipitated here was taken out, and the solvent was removed by drying at 2.6kPa and 80 ℃ for about 1 hour to obtain a resin composition (A-1) containing a lactone ring-containing (meth) acrylic polymer and a graft copolymer in which the polymer chain was grafted to a polyisoprene chain. The weight-average molecular weight of the resin composition (A-1) was 13.8 ten thousand, the number-average molecular weight was 3.8 ten thousand, and the chloroform-insoluble content was 2%.

(2-2) example 2: preparation of resin composition (A-2)

To a reactor equipped with a stirrer, a temperature sensor, a cooling tube and a nitrogen gas inlet tube, 3 parts of an esterification product of a maleic anhydride adduct of polyisoprene and 2-hydroxyethyl methacrylate (UC-102M, manufactured by KURARAAY Co., Ltd.), 23 parts of Methyl Methacrylate (MMA), 3 parts of Phenylmaleimide (PMI) and 50 parts of toluene as a polymerization solvent were added, and the temperature was raised to 105 ℃ while passing nitrogen gas therethrough. Then, 0.09 part of t-amyl peroxy isononanoate (LUPEROX (registered trademark) 570, manufactured by ARKEMA GYFI.) as an initiator was added thereto, and solution polymerization was carried out at 105 ℃ and 110 ℃ for 30 minutes. Thus, a resin composition containing a maleimide ring-containing (meth) acrylic polymer and a graft copolymer in which the polymer chain is grafted to a polyisoprene chain was obtained. The reactivity of MMA calculated from the amount of residual monomer in the polymerization reaction liquid was 14%, and the reactivity of PMI was 21%. The composition ratio of the (meth) acrylic polymer chain bonded to the polyisoprene chain, calculated from the reaction rate, to the (meth) acrylic polymer (mass basis) was MMA: PMI 83.6: 16.4, the content of the unit derived from the (meth) acrylate was 83.6% by mass, and the content of the cyclic structure unit was 16.4% by mass. When a part of the reaction solution is taken out to carry out a filtration experiment, filtration can be preferably carried out.

Then, 50 parts of Methyl Ethyl Ketone (MEK) was added to the obtained reaction solution to dilute the solution, and the diluted solution was filtered through a PTFE filter having a pore size of 10 μm, and then slowly added to a large amount of methanol while stirring the solution. The white solid precipitated here was taken out, and the solvent was removed by drying at 2.6kPa and 80 ℃ for about 1 hour to obtain a resin composition (A-2) containing a maleimide ring-containing (meth) acrylic polymer and a graft copolymer in which the polymer chain was grafted to a polyisoprene chain. The weight-average molecular weight of the resin composition (A-2) was 11.1 ten thousand, the number-average molecular weight was 3.1 ten thousand, and the chloroform-insoluble content was 3%.

(2-3) comparative example 1: preparation of resin composition (A-3)

Into a reactor equipped with a stirrer, a temperature sensor, a cooling tube and a nitrogen gas inlet tube, 3 parts of an esterified product of a maleic anhydride adduct of polyisoprene and 2-hydroxyethyl methacrylate (UC-102M, manufactured by KURARAAY corporation), 27 parts of Methyl Methacrylate (MMA) and 50 parts of toluene as a polymerization solvent were charged, and the temperature was raised to 105 ℃ while passing nitrogen gas therethrough. Then, 0.09 part of t-amyl peroxy isononanoate (LUPEROX (registered trademark) 570, manufactured by ARKEMA GYFI.) as an initiator was added thereto, and solution polymerization was carried out at 105 ℃ and 110 ℃ for 30 minutes. Thus, a resin composition containing a methyl methacrylate Polymer (PMMA) and a graft copolymer in which the polymer chain is grafted to a polyisoprene chain was obtained. The reaction rate of MMA was 16% as calculated from the amount of the residual monomer in the polymerization reaction liquid.

Then, 50 parts of Methyl Ethyl Ketone (MEK) was added to the obtained reaction solution to dilute the reaction solution, and then the diluted solution was gradually added to a large amount of methanol while stirring the solution. The white solid precipitated here was taken out, and the solvent was removed by drying at 80 ℃ for about 1 hour under 2.6kPa to obtain a resin composition (A-3) containing a methyl methacrylate Polymer (PMMA) and a graft copolymer in which the polymer chain was grafted to a polyisoprene chain. The weight-average molecular weight of the resin composition (A-3) was 12.4 ten thousand, and the number-average molecular weight was 3.1 ten thousand.

(2-4) comparative example 2: synthesis of resin composition (B-1)

To a reactor equipped with a stirrer, a temperature sensor, a cooling tube, and a nitrogen introduction tube, 48 parts of Methyl Methacrylate (MMA), 2 parts of methyl 2- (hydroxymethyl) acrylate (MHMA), and 50 parts of toluene as a polymerization solvent were added, and the temperature was raised to 105 ℃ while passing nitrogen therethrough. Then, 0.2 part of t-amyl peroxy isononanoate (LUPEROX (registered trademark) 570, manufactured by ARKEMA GYFI.) as an initiator was added thereto, and solution polymerization was carried out at 105 ℃ and 110 ℃ for 180 minutes. Herein, 0.01 part of octadecyl phosphate as a cyclization catalyst was added, and after 1 hour of reaction, the reaction mixture was heated at 240 ℃ for 1 hour in an autoclave. Thus, a resin composition containing a lactone ring-containing (meth) acrylic polymer was obtained. The reaction rate of MMA calculated from the amount of residual monomer in the polymerization reaction liquid was 82%, and the reaction rate of MHMA was 88%. The composition ratio of the lactone ring-containing (meth) acrylic polymer calculated from the reaction rate (mass basis) was MMA: MHMA 95.7: 4.3, the content of the unit derived from (meth) acrylate was 93.1% by mass, and the content of the cyclic structure unit was 6.4% by mass.

Then, 50 parts of Methyl Ethyl Ketone (MEK) was added to the obtained reaction solution to dilute the reaction solution, and then the diluted solution was gradually added to a large amount of methanol while stirring the solution. The white solid precipitated here was taken out, and the solvent was removed by drying at 200 ℃ for about 1 hour under 2.6kPa to obtain a resin composition (B-1) containing a lactone ring-containing (meth) acrylic polymer. The weight-average molecular weight of the resin composition (B-1) was 13.8 ten thousand, and the number-average molecular weight was 5.7 ten thousand.

(2-5) comparative example 3: preparation of resin composition (B-2)

To a reactor equipped with a stirrer, a temperature sensor, a cooling tube, and a nitrogen introduction tube, 47 parts of Methyl Methacrylate (MMA), 3 parts of PMI, and 50 parts of toluene as a polymerization solvent were added, and the temperature was raised to 105 ℃ while passing nitrogen therethrough. Then, 0.2 part of t-amyl peroxy isononanoate (LUPEROX (registered trademark) 570, manufactured by ARKEMA GYFI.) as an initiator was added thereto, and solution polymerization was carried out at 105 ℃ and 110 ℃ for 180 minutes. Thus, a resin composition containing a maleimide ring-containing (meth) acrylic polymer was obtained. The reactivity of MMA calculated from the amount of residual monomer in the polymerization reaction liquid was 85%, and the reactivity of PMI was 82%. The composition ratio of the maleimide ring-containing (meth) acrylic polymer calculated from the reaction rate (mass basis) was MMA: PMI 94.2: 5.8, the content of the unit derived from (meth) acrylate was 94.2% by mass, and the content of the cyclic structure unit was 5.8% by mass.

Then, 50 parts of Methyl Ethyl Ketone (MEK) was added to the obtained reaction solution to dilute the reaction solution, and then the diluted solution was gradually added to a large amount of methanol while stirring the solution. The white solid precipitated here was taken out, and the solvent was removed by drying at 200 ℃ for about 1 hour under 2.6kPa to obtain a resin composition (B-2) containing a maleimide ring-containing (meth) acrylic polymer. The weight-average molecular weight of the resin composition (B-2) was 12.9 ten thousand, and the number-average molecular weight was 5.9 ten thousand.

(2-6) example 3: preparation of resin composition (C-1)

After 1 part of the resin composition (A-1) obtained in example 1 and 9 parts of the resin composition (B-1) obtained in comparative example 2 were dissolved in 40 parts of MEK and mixed, the solvent was removed by drying at 150 ℃ and 2.6kPa for about 1 hour to obtain a resin composition (C-1). The weight-average molecular weight of the resin composition (C-1) was 13.0 ten thousand, and the number-average molecular weight was 5.9 ten thousand.

(2-7) example 4: preparation of resin composition (C-2)

1 part of the resin composition (A-2) obtained in example 2, 9 parts of the resin composition (B-2) obtained in comparative example 3, 0.01 part of an ultraviolet absorber (LA-31, manufactured by ADEKA), 0.001 part of an antioxidant (Irganox (registered trademark) 1010, manufactured by BASF), and 0.001 part of an antioxidant (PEP-36, manufactured by ADEKA) were dissolved in and mixed with 40 parts of MEK, and then the mixture was dried at 150 ℃ under 2.6kPa for about 1 hour to remove the solvent, thereby obtaining a resin composition (C-2). The weight-average molecular weight of the resin composition (C-2) was 13.2 ten thousand, and the number-average molecular weight was 5.1 ten thousand.

(2-8) comparative example 4: preparation of resin composition (A-4)

Polymerization and cyclization reactions were carried out in the same manner as in example 1 except for using 3 parts of an esterification product of a maleic anhydride adduct of polyisoprene and 2-hydroxyethyl methacrylate, 26.7 parts of MMA, and 0.3 part of MMA in example 1. The reaction rate of MMA calculated from the amount of residual monomer in the polymerization reaction liquid was 18%, and the reaction rate of MHMA was 12%. The composition ratio of the (meth) acrylic polymer chain bonded to the polyisoprene chain, calculated from the reaction rate, to the (meth) acrylic polymer (mass basis) was MMA: MHMA 99.3: 0.7, the content of the unit derived from (meth) acrylate was 98.9% by mass, and the content of the cyclic structure unit was 1.0% by mass. When a part of the reaction solution is taken out to carry out a filtration experiment, filtration can be preferably carried out. Subsequently, the obtained reaction solution was filtered, reprecipitated and dried in the same manner as in example 1 to obtain a resin composition (a-4) containing a lactone ring-containing (meth) acrylic polymer and a graft copolymer in which the polymer chain was grafted to a polyisoprene chain. The weight-average molecular weight of the resin composition (A-4) was 12.2 ten thousand, the number-average molecular weight was 3.1 ten thousand, and the chloroform-insoluble content was 2%.

(2-9) comparative example 5: preparation of resin composition (B-3)

In comparative example 2, polymerization and cyclization reactions were carried out in the same manner as in comparative example 2 except that 49 parts of MMA and 1 part of MHMA were used. The reaction rate of MMA calculated from the amount of residual monomer in the polymerization reaction liquid was 81%, and the reaction rate of MHMA was 89%. The composition ratio of the lactone ring-containing (meth) acrylic polymer calculated from the reaction rate (mass basis) was MMA: MHMA 97.8: 2.2, the content of the unit derived from (meth) acrylate was 96.5% by mass, and the content of the cyclic structure unit was 3.2% by mass. Then, the obtained reaction solution was filtered, reprecipitated and dried in the same manner as in comparative example 2 to obtain a resin composition (B-3) containing a lactone ring-containing (meth) acrylic polymer. The weight-average molecular weight of the resin composition (B-3) was 14.5 ten thousand, and the number-average molecular weight was 6.3 ten thousand.

(2-10) comparative example 6: preparation of resin composition (C-3)

After 1 part of the resin composition (A-4) obtained in comparative example 4 and 9 parts of the resin composition (B-3) obtained in comparative example 5 were dissolved in 40 parts of MEK and mixed, the solvent was removed by drying at 150 ℃ and 2.6kPa for about 1 hour to obtain a resin composition (C-3). The weight-average molecular weight of the resin composition (C-3) was 14.4 ten thousand, and the number-average molecular weight was 6.0 ten thousand.

(2-11) comparative example 7: preparation of resin composition (A-5)

Polymerization and cyclization reactions were carried out in the same manner as in example 1 except that 3 parts of an esterification product of a maleic anhydride adduct of polyisoprene and 2-hydroxyethyl methacrylate, 13 parts of MMA, 13 parts of MHMA, and 0.03 part of octadecyl phosphate as a cyclization catalyst were used in example 1. The reaction rate of MMA calculated from the amount of residual monomer in the polymerization reaction liquid was 19% and the reaction rate of MHMA was 13%. The composition ratio of the (meth) acrylic polymer chain bonded to polyisoprene, calculated from the reaction rate, to the (meth) acrylic polymer (mass basis) was MMA: MHMA 59.4: 40.6, the content of the unit derived from the (meth) acrylate was 27.4% by mass, and the content of the cyclic structure unit was 67.1% by mass. When a part of the reaction solution was taken out and subjected to a filtration experiment, the pressure of the filter was increased. Subsequently, the obtained reaction solution was filtered, reprecipitated and dried in the same manner as in example 1 to obtain a resin composition (a-5) containing a lactone ring-containing (meth) acrylic polymer and a graft copolymer in which the polymer chain was grafted to polyisoprene. The weight-average molecular weight of the resin composition (A-5) was 18.1 ten thousand, the number-average molecular weight was 3.2 ten thousand, and the chloroform-insoluble content was 11%.

(2-12) comparative example 8: preparation of resin composition (B-4)

In comparative example 2, polymerization and cyclization reactions were carried out in the same manner as in comparative example 2 except that 25 parts of MMA and 25 parts of MHMA were used. The reaction rate of MMA calculated from the amount of residual monomer in the polymerization reaction liquid was 87%, and the reaction rate of MHMA was 85%. The composition ratio of the lactone ring-containing (meth) acrylic polymer calculated from the reaction rate (mass basis) was MMA: MHMA 50.6: 49.4, the content of the unit derived from (meth) acrylate was 9.2% by mass, and the content of the cyclic structure unit was 83.9% by mass. Then, the obtained reaction solution was filtered, reprecipitated and dried in the same manner as in comparative example 2 to obtain a resin composition (B-4) containing a lactone ring-containing (meth) acrylic polymer. The weight-average molecular weight of the resin composition (B-4) was 18.9 ten thousand, and the number-average molecular weight was 5.2 ten thousand.

(2-13) comparative example 9: preparation of resin composition (C-4)

1 part of the resin composition (A-5) obtained in comparative example 7 and 9 parts of the resin composition (B-4) obtained in comparative example 8 were dissolved in 40 parts of MEK and mixed, and then the solvent was removed by drying at 150 ℃ and 2.6kPa for about 1 hour to obtain a resin composition (C-4). The weight-average molecular weight of the resin composition (C-4) was 17.8 ten thousand, and the number-average molecular weight was 5.0 ten thousand.

(2-14) example 5: preparation of resin composition (D-1)

To a reactor equipped with a stirrer, a temperature sensor, a cooling tube and a nitrogen gas inlet tube, 5 parts of an SEBS triblock copolymer (manufactured by Kraton, A1536; amount of olefinic double bonds 0.10 mmol/g; styrene unit content 39 mass%, refractive index 1.519), 73 parts of Methyl Methacrylate (MMA), 18 parts of Phenylmaleimide (PMI), 0.05 part of n-dodecylmercaptan (nDM) and 100 parts of toluene as a polymerization solvent were added, and the temperature was raised to 105 ℃ while passing nitrogen gas therethrough. Then, 0.009 parts of t-butyl peroxyisopropyl carbonate (Kayakaron (registered trademark) Bic75, manufactured by Kayakaro Akzo Co., Ltd.) was added as an initiator, and 5 parts of styrene (St) and 0.018 parts of t-butyl peroxyisopropyl carbonate diluted with 1 part of toluene were solution-polymerized at 105 ℃ and 110 ℃ while dropping at a constant rate for 3 hours, followed by aging for 4 hours. Thus, a resin composition containing a maleimide ring-containing (meth) acrylic polymer obtained by polymerizing MMA, PMI and St, and a graft copolymer having the polymer chain bonded to the SEBS triblock polymer chain was obtained. The reactivity of MMA calculated from the amount of residual monomer in the polymerization reaction liquid was 95%, the reactivity of PMI was 98%, and the reactivity of St was 100%. The composition ratio of the (meth) acrylic polymer chain bonded to the SEBS triblock polymer chain calculated from the reaction rate to the (meth) acrylic polymer (mass basis) was MMA: PMI: st 75.9: 18.9: 5.2, the content of the unit derived from the (meth) acrylate was 75.9% by mass, and the content of the cyclic structure unit was 18.9% by mass. When a part of the reaction solution is taken out to carry out a filtration experiment, filtration can be preferably carried out.

The obtained polymerization reaction liquid was introduced into a vented screw twin-screw extruder (bore diameter: 15mm, L/D: 45) having a rear vent number of 1 and a front vent number of 2 at a processing speed of 600g/h in terms of resin, and devolatilized in the extruder to obtain transparent pellets of a resin composition (D-1) containing a maleimide ring-containing (meth) acrylic polymer and a graft copolymer having a polymer chain bonded to an SEBS triblock polymer chain. Further, the operating conditions of the twin-screw extruder were a barrel temperature of 260 ℃, a rotation speed of 300rpm, and a decompression degree of 13.3 to 400hPa (10 to 300 mmHg). The weight average molecular weight of the resin composition (D-1) was 15.0 ten thousand, the number average molecular weight was 6.0 ten thousand, the glass transition temperature on the high temperature side was 138 ℃, the glass transition temperature on the low temperature side was-68 ℃, the chloroform-insoluble fraction was 0.3%, and the refractive index was 1.517. The in-plane retardation Re and the thickness-direction retardation Rth of the stretched film of the resin composition (D-1) were 0.9nm and 2.9nm, respectively.

(2-15) example 6: preparation of resin composition (D-2)

Polymerization was carried out in the same manner as in example 5 except that 10 parts of an SEBS triblock copolymer (manufactured by Kraton, A1536), 69 parts of MMA and 17 parts of PMI were used as the monomer component initially charged in the reactor in example 5. The reactivity of MMA calculated from the amount of residual monomer in the polymerization reaction liquid was 96%, the reactivity of PMI was 99%, and the reactivity of St was 100%. The composition ratio of the acrylic polymer chain bonded to the SEBS triblock copolymer chain, calculated from the reaction rate, to the (meth) acrylic polymer (mass basis) was MMA: PMI: st 75.2: 19.1: 5.7, the content of the unit derived from (meth) acrylate was 75.2% by mass, and the content of the cyclic structure unit was 19.1% by mass. When a part of the reaction solution is taken out to carry out a filtration experiment, filtration can be preferably carried out. The obtained polymerization reaction liquid was devolatilized in an extruder in the same manner as in example 6 to obtain transparent pellets of the resin composition (D-2). The weight average molecular weight of the resin composition (D-2) was 14.8 ten thousand, the number average molecular weight was 5.9 ten thousand, the glass transition temperature on the high temperature side was 138 ℃, the glass transition temperature on the low temperature side was-68 ℃, the chloroform-insoluble fraction was 0.3%, and the refractive index was 1.517. The island size of the sea-island structure of the undrawn film of the resin composition (D-2) was 200nm, and the in-plane retardation Re and the retardation Rth in the thickness direction of the drawn film were 0.2nm and 3.5nm, respectively.

(2-16) example 7: preparation of resin composition (D-3)

Polymerization was carried out in the same manner as in example 5 except that 15 parts of SEBS triblock copolymer (manufactured by Kraton, A1536), 65 parts of MMA and 16 parts of PMI were used as the monomer components initially charged in the reactor in example 5 and 4 parts of monomer component St was added dropwise. The reactivity of MMA calculated from the amount of residual monomer in the polymerization reaction liquid was 96%, the reactivity of PMI was 99%, and the reactivity of St was 100%. The composition ratio of the (meth) acrylic polymer chain bonded to the SEBS triblock polymer chain calculated from the reaction rate to the (meth) acrylic polymer (mass basis) was MMA: PMI: st 75.9: 19.3: 4.9, the content of the unit derived from (meth) acrylate was 75.9% by mass, and the content of the cyclic structure unit was 19.3% by mass. When a part of the reaction solution is taken out to carry out a filtration experiment, filtration can be preferably carried out. The obtained polymerization reaction liquid was devolatilized in an extruder in the same manner as in example 5 to obtain transparent pellets of the resin composition (D-3). The weight average molecular weight of the resin composition (D-3) was 14.0 ten thousand, the number average molecular weight was 5.3 ten thousand, the glass transition temperature on the high temperature side was 137 ℃ and the glass transition temperature on the low temperature side was-68 ℃, the chloroform-insoluble fraction was 0.3%, and the refractive index was 1.517. The island size of the sea-island structure of the undrawn film of the resin composition (D-3) was 200nm, and the in-plane retardation Re and the retardation Rth in the thickness direction of the drawn film were 0.8nm and 4.5nm, respectively.

(2-17) example 8: preparation of resin composition (D-4)

Polymerization was carried out in the same manner as in example 5 except that 20 parts of SEBS triblock copolymer (manufactured by Kraton, A1536), 61 parts of MMA, and 15 parts of PMI were used as the monomer component initially charged in the reactor in example 5, and 4 parts of monomer component St was used as the monomer component added dropwise. The reactivity of MMA calculated from the amount of residual monomer in the polymerization reaction liquid was 97%, the reactivity of PMI was 99%, and the reactivity of St was 100%. The composition ratio of the (meth) acrylic polymer chain bonded to the SEBS triblock polymer chain calculated from the reaction rate to the (meth) acrylic polymer (mass basis) was MMA: PMI: st 76.1: 18.8: 5.1, the content of the unit derived from (meth) acrylate was 76.1% by mass, and the content of the cyclic structure unit was 18.8% by mass. When a part of the reaction solution is taken out to carry out a filtration experiment, filtration can be preferably carried out. The obtained polymerization reaction liquid was devolatilized in an extruder in the same manner as in example 5 to obtain transparent pellets of the resin composition (D-4). The weight average molecular weight of the resin composition (D-4) was 14.5 ten thousand, the number average molecular weight was 6.0 ten thousand, the glass transition temperature on the high temperature side was 136 ℃, the glass transition temperature on the low temperature side was-68 ℃, the chloroform-insoluble content was 0.4%, and the refractive index was 1.517. The island size of the sea-island structure of the undrawn film of the resin composition (D-4) was 250nm, and the in-plane retardation Re and the retardation Rth in the thickness direction of the drawn film were 0.5nm and 6.2nm, respectively.

(2-18) example 9: preparation of resin composition (D-5)

Polymerization was carried out in the same manner as in example 5 except that 10 parts of SEBS triblock copolymer (product No. 200557, product No. 0.10mmol/g of olefinic double bond, styrene unit content 26% by mass, refractive index 1.513), 72 parts of MMA and 16 parts of PMI were used as the monomer component initially charged in the reactor, and 2 parts of monomer component St was used as the monomer component added dropwise in example 5. The reactivity of MMA calculated from the amount of residual monomer in the polymerization reaction liquid was 96%, the reactivity of PMI was 99%, and the reactivity of St was 100%. The composition ratio of the (meth) acrylic polymer chain bonded to the SEBS triblock polymer chain calculated from the reaction rate to the (meth) acrylic polymer (mass basis) was MMA: PMI: st 79.4: 18.3: 2.3, the content of the unit derived from the (meth) acrylate was 79.4% by mass, and the content of the cyclic structure unit was 18.3% by mass. When a part of the reaction solution is taken out to carry out a filtration experiment, filtration can be preferably carried out. The obtained polymerization reaction liquid was devolatilized in an extruder in the same manner as in example 5 to obtain transparent pellets of the resin composition (D-5). The weight-average molecular weight of the resin composition (D-5) was 17.2 ten thousand, the number-average molecular weight was 7.1 ten thousand, the glass transition temperature was 138 ℃, the chloroform-insoluble content was 0.4%, and the refractive index was 1.515. The island size of the sea-island structure of the undrawn film of the resin composition (D-5) was 250nm, and the in-plane retardation Re and the retardation Rth in the thickness direction of the drawn film were 0.5nm and 4.9nm, respectively.

(2-19) example 10: preparation of resin composition (D-6)

Polymerization was carried out in the same manner as in example 5 except that 10 parts of an SEBS triblock copolymer (Tuftec (registered trademark) H1041, manufactured by Asahi chemical Co., Ltd., having an olefinic double bond content of 0.44mmol/g, a styrene unit content of 30% by mass and a refractive index of 1.515), 70 parts of MMA and 16 parts of PMI were used as a monomer component added first to the reactor, and 4 parts of the monomer component St was used as added dropwise in example 5. The reactivity of MMA calculated from the amount of residual monomer in the polymerization reaction liquid was 97%, the reactivity of PMI was 99%, and the reactivity of St was 100%. The composition ratio of the (meth) acrylic polymer chain bonded to the SEBS triblock polymer chain calculated from the reaction rate to the (meth) acrylic polymer (mass basis) was MMA: PMI: st 77.4: 18.1: 4.6, the content of the unit derived from (meth) acrylate was 77.4% by mass, and the content of the cyclic structure unit was 18.1% by mass. When a part of the reaction solution is taken out to carry out a filtration experiment, filtration can be preferably carried out. The obtained polymerization reaction liquid was devolatilized in an extruder in the same manner as in example 5 to obtain transparent pellets of the resin composition (D-6). The weight-average molecular weight of the resin composition (D-6) was 13.5 ten thousand, the number-average molecular weight was 5.6 ten thousand, the glass transition temperature was 138 ℃, the chloroform-insoluble content was 0.5%, and the refractive index was 1.516. The island size of the sea-island structure of the undrawn film of the resin composition (D-6) was 300nm, and the in-plane retardation Re and the retardation Rth in the thickness direction of the drawn film were 0.3nm and 2.3nm, respectively.

(2-20) example 11: preparation of resin composition (D-7)

Polymerization was carried out in the same manner as in example 5 except that 10 parts of an SEBS triblock copolymer (Tuftec (registered trademark) P1083, manufactured by Asahi chemical Co., Ltd., having an olefinic double bond content of 2.40mmol/g and a styrene unit content of 20% by mass and a refractive index of 1.500), 83 parts of MMA and 6 parts of PMI were used as the monomer component added first to the reactor, and 1 part of the monomer component St was used as added dropwise. The reactivity of MMA calculated from the amount of residual monomer in the polymerization reaction liquid was 96%, the reactivity of PMI was 99%, and the reactivity of St was 100%. The composition ratio of the (meth) acrylic polymer chain bonded to the SEBS triblock polymer chain calculated from the reaction rate to the (meth) acrylic polymer (mass basis) was MMA: PMI: st 92.6: 6.3: 1.1, the content of the unit derived from (meth) acrylate was 92.6% by mass, and the content of the cyclic structure unit was 6.3% by mass. When a part of the reaction solution is taken out to carry out a filtration experiment, filtration can be preferably carried out. The obtained polymerization reaction liquid was devolatilized in an extruder in the same manner as in example 5 to obtain transparent pellets of the resin composition (D-7). The resin composition (D-7) had a weight-average molecular weight of 16.3 ten thousand, a number-average molecular weight of 6.2 ten thousand, a glass transition temperature of 123 ℃, a chloroform-insoluble fraction of 0.9%, and a refractive index of 1.500. The in-plane retardation Re and the thickness-direction retardation Rth of the stretched film of the resin composition (D-7) were 0.3nm and 4.5nm, respectively.

(2-21) example 12: preparation of resin composition (D-8)

Polymerization was carried out in the same manner as in example 5 except that 10 parts of an SEBS triblock copolymer (Tuftec (registered trademark) H1517, manufactured by Asahi chemical Co., Ltd., having an olefinic double bond content of 0.11mmol/g, a styrene unit content of 43% by mass and a refractive index of 1.525), 63 parts of MMA and 24 parts of PMI were used as a monomer component added first to the reactor, and 3 parts of the monomer component St was used as added dropwise in example 5. The reactivity of MMA calculated from the amount of residual monomer in the polymerization reaction liquid was 95%, the reactivity of PMI was 98%, and the reactivity of St was 100%. The composition ratio of the (meth) acrylic polymer chain bonded to the SEBS triblock polymer chain calculated from the reaction rate to the (meth) acrylic polymer (mass basis) was MMA: PMI: st 69.3: 27.2: 3.5, the content of the unit derived from the (meth) acrylate was 69.3% by mass, and the content of the cyclic structure unit was 27.2% by mass. When a part of the reaction solution is taken out to carry out a filtration experiment, filtration can be preferably carried out. The obtained polymerization reaction liquid was devolatilized in an extruder in the same manner as in example 5 to obtain transparent pellets of the resin composition (D-8). The weight average molecular weight of the resin composition (D-8) was 16.6 ten thousand, the number average molecular weight was 6.3 ten thousand, the glass transition temperature was 151 ℃, the chloroform-insoluble content was 0.5%, and the refractive index was 1.525. The in-plane retardation Re and the thickness-direction retardation Rth of the stretched film of the resin composition (D-8) were 0.5nm and 5.9nm, respectively.

(2-22) comparative example 10: preparation of resin composition (D-9)

Polymerization was carried out in the same manner as in example 5 except that 10 parts of SEBS triblock copolymer (Dynaron (registered trademark) 9901P, manufactured by JSR., amount of olefinic double bonds 0.06mmol/g, styrene unit content 50% by mass, refractive index 1.530), 30 parts of MMA and 55 parts of PMI were used as the monomer component initially charged in the reactor in example 5, and 5 parts of monomer component St added dropwise were used. The reactivity of MMA calculated from the amount of residual monomer in the polymerization reaction liquid was 98%, the reactivity of PMI was 98%, and the reactivity of St was 100%. The composition ratio of the (meth) acrylic polymer chain bonded to the SEBS triblock polymer chain calculated from the reaction rate to the (meth) acrylic polymer (mass basis) was MMA: PMI: st 33.3: 61.0: 5.7, the content of the unit derived from (meth) acrylate was 33.3% by mass, and the content of the cyclic structure unit was 61.0% by mass. When a part of the reaction solution is taken out to carry out a filtration experiment, filtration can be preferably carried out. The obtained polymerization reaction liquid was devolatilized in an extruder in the same manner as in example 5 to obtain transparent pellets of the resin composition (D-9). The weight average molecular weight of the resin composition (D-9) was 14.9 ten thousand, the number average molecular weight was 5.9 ten thousand, the glass transition temperature was 201 ℃, the chloroform-insoluble content was 2.1%, and the refractive index was 1.560. Further, the non-stretched film of the resin composition (D-9) was tried to be stretched, and it was not stretched due to insufficient strength.

(2-23) comparative example 11: preparation of resin composition (D-10)

Polymerization was carried out in the same manner as in example 5 except that 10 parts of SEBS triblock copolymer (H1052, amount of olefinic double bond 0.27mmol/g, styrene unit content 20% by mass, refractive index 1.500) and 88.5 parts of MMA and 1.5 parts of PMI were used as the monomer component initially charged in the reactor in example 5, and monomer component St added dropwise was not used. The reactivity of MMA calculated from the amount of residual monomer in the polymerization reaction liquid was 98%, and the reactivity of PMI was 98%. The composition ratio of the (meth) acrylic polymer chain bonded to the SEBS triblock polymer chain calculated from the reaction rate to the (meth) acrylic polymer (mass basis) was MMA: PMI 98.3: 1.7, the content of the unit derived from (meth) acrylate was 98.3% by mass, and the content of the cyclic structure unit was 1.7% by mass. When a part of the reaction solution is taken out to carry out a filtration experiment, filtration can be preferably carried out. The obtained polymerization reaction liquid was devolatilized in an extruder in the same manner as in example 5 to obtain transparent pellets of the resin composition (D-10). The weight average molecular weight of the resin composition (D-10) was 14.5 ten thousand, the number average molecular weight was 6.0 ten thousand, the glass transition temperature was 112 ℃, the chloroform-insoluble content was 0.4%, and the refractive index was 1.500.

(2-24) example 13: preparation of resin composition (D-11)

To a reactor equipped with a stirrer, a temperature sensor, a cooling tube and a nitrogen gas inlet tube, 10 parts of an SEBS triblock copolymer (H1052, manufactured by Asahi Kasei corporation, amount of olefinic double bonds 0.27mmol/g, styrene unit content 20% by mass, refractive index 1.500), 75 parts of Methyl Methacrylate (MMA), 13.5 parts of methyl 2- (hydroxymethyl) acrylate (MHMA), 0.05 part of n-dodecylmercaptan (nDM) and 100 parts of toluene as a polymerization solvent were added, and the temperature was raised to 105 ℃ while passing nitrogen gas therethrough. Then, 0.009 parts of t-butyl peroxyisopropyl carbonate (Kayakaron (registered trademark) Bic75, manufactured by Kayakaro Akzo Co., Ltd.) was added as an initiator, and 2 parts of styrene (St) and 0.015 part of t-butyl peroxyisopropyl carbonate diluted with 1 part of toluene were solution-polymerized at 105 ℃ and 110 ℃ while dropping at a constant rate for 2 hours, and further aged for 4 hours. To this, 0.07 part of octadecyl phosphate as a cyclization catalyst was added, and cyclization reaction was carried out at 90 to 110 ℃ under reflux for 2 hours. Thus, a resin composition containing a lactone ring-containing (meth) acrylic polymer formed by polymerization of MMA, MHMA and St, and a graft copolymer in which the polymer chain is bonded to a SEBS triblock polymer chain was obtained. The reaction rate of MMA calculated from the amount of residual monomer in the polymerization reaction liquid was 94%, the reaction rate of MHMA was 94%, and the reaction rate of St was 99%. The composition ratio of the (meth) acrylic polymer chain bonded to the SEBS triblock copolymer chain calculated from the reaction rate to the (meth) acrylic polymer (mass basis) was MMA: MHMA: st 82.6: 14.9: 2.5, the content of the (meth) acrylate-derived unit was 72.9% by mass, the content of the cyclic structure unit was 22.8% by mass, and the content of the styrene-derived unit was 2.4% by mass. When a part of the reaction solution is taken out to carry out a filtration experiment, filtration can be preferably carried out.

The resulting polymerization reaction solution was heated at 240 ℃ for 1 hour in an autoclave, and then introduced into a vented screw twin screw extruder (pore diameter: 15mm, L/D: 45) having 1 rear vent and 2 front vents at a processing speed of 600g/h in terms of resin, and devolatilized in the extruder to obtain transparent pellets of a resin composition (D-11) containing a lactone ring-containing (meth) acrylic polymer and a graft copolymer in which the polymer chains are bonded to SEBS triblock polymer chains by extrusion. Further, the operating conditions of the twin-screw extruder were a barrel temperature of 260 ℃, a rotation speed of 300rpm, and a decompression degree of 13.3 to 400hPa (10 to 300 mmHg). The weight average molecular weight of the resin composition (D-11) was 15.5 ten thousand, the number average molecular weight was 5.9 ten thousand, the glass transition temperature on the high temperature side was 127 ℃, the glass transition temperature on the low temperature side was-54 ℃, the chloroform-insoluble content was 0.4%, and the refractive index was 1.500. The island size of the sea-island structure of the undrawn film of the resin composition (D-11) was 250nm, and the in-plane retardation Re and the retardation Rth in the thickness direction of the drawn film were 0.3nm and 4.9nm, respectively.

(2-25) example 14: preparation of resin composition (D-12)

Polymerization and cyclization reactions were carried out in the same manner as in example 13 except that 10 parts of an SEBS triblock copolymer (HYBRAR (registered trademark) 7125, manufactured by KURARAY Co., Ltd., olefinic double bond content 0.44mmol/g, styrene unit content 20 mass%) 10 parts, 75 parts of MMA, and 13.5 parts of MHMA were used as the monomer component initially charged in the reactor in example 13. The reaction rate of MMA calculated from the amount of residual monomer in the polymerization reaction liquid was 94%, the reaction rate of MHMA was 94%, and the reaction rate of St was 100%. The composition ratio of the (meth) acrylic polymer chain bonded to the SEBS triblock polymer chain calculated from the reaction rate to the (meth) acrylic polymer (mass basis) was MMA: MHMA: st 82.7: 14.8: 2.5, the content of the (meth) acrylate-derived unit was 73.0% by mass, the content of the cyclic structure unit was 22.7% by mass, and the content of the styrene-derived unit was 2.4% by mass. When a part of the reaction solution is taken out to carry out a filtration experiment, filtration can be preferably carried out. The obtained polymerization reaction solution was treated in an autoclave in the same manner as in example 13, and then devolatilized in an extruder to obtain transparent pellets of the resin composition (D-12). The resin composition (D-12) had a weight-average molecular weight of 16.2 ten thousand, a number-average molecular weight of 6.1 ten thousand, a glass transition temperature of 127 ℃, a chloroform-insoluble fraction of 0.4% and a refractive index of 1.500. The island size of the sea-island structure of the undrawn film of the resin composition (D-12) was 250nm, and the in-plane retardation Re and the retardation Rth in the thickness direction of the drawn film were 0.2nm and 4.5nm, respectively.

(2-26) example 15: preparation of resin composition (D-13)

In example 13, polymerization and cyclization reactions were carried out in the same manner as in example 13 except that 6 parts of SEBS triblock copolymer (Tuftec (registered trademark) P1083, manufactured by asahi chemical corporation, having an olefinic double bond content of 2.01mmol/g and a styrene unit content of 20 mass%), 4 parts of SEBS triblock copolymer 2 (Tuftec (registered trademark) H1052, manufactured by asahi chemical corporation, having an olefinic double bond content of 0.27mmol/g, a styrene unit content of 20 mass%, a refractive index of 1.500), 4 parts of MMA75 and 13.5 parts of MHMA were used as the monomer component St to be added dropwise as the monomer component to be added first to the reactor, and 4 parts of the monomer component St was used. The reaction rate of MMA calculated from the amount of residual monomer in the polymerization reaction liquid was 94%, the reaction rate of MHMA was 94%, and the reaction rate of St was 100%. The composition ratio of the (meth) acrylic polymer chain bonded to the SEBS triblock polymer chain calculated from the reaction rate to the (meth) acrylic polymer (mass basis) was MMA: MHMA: st 82.6: 14.9: 2.5, the content of the (meth) acrylate-derived unit was 72.6% by mass, the content of the cyclic structure unit was 23.0% by mass, and the content of the styrene-derived unit was 2.4% by mass. When a part of the reaction solution is taken out to carry out a filtration experiment, filtration can be preferably carried out. The obtained polymerization reaction solution was treated in an autoclave in the same manner as in example 13, and then devolatilized in an extruder to obtain transparent pellets of the resin composition (D-13). The weight-average molecular weight of the resin composition (D-13) was 15.1 ten thousand, the number-average molecular weight was 5.7 ten thousand, the glass transition temperature on the high temperature side was 127 ℃, the glass transition temperature on the low temperature side was-61 ℃, the chloroform-insoluble content was 0.4%, and the refractive index was 1.500. The island size of the sea-island structure of the undrawn film of the resin composition (D-13) was 150nm, and the in-plane retardation Re and the thickness-direction retardation Rth of the drawn film were 0.3nm and 3.5nm, respectively.

(2-27) comparative example 12: preparation of resin composition (D-14)

Polymerization was carried out in the same manner as in example 13 except that 10 parts of SEBS triblock copolymer (Tuftec (registered trademark) H1041, manufactured by Asahi chemical Co., Ltd., amount of olefinic double bonds 0.45mmol/g, content of styrene units 30% by mass), 40 parts of MMA, and 45 parts of MHMA were used as the monomer component added first to the reactor, and 5 parts of monomer component St was used as the monomer component added dropwise. The reaction rate of MMA calculated from the amount of residual monomer in the polymerization reaction liquid was 94%, the reaction rate of MHMA was 90%, and the reaction rate of St was 100%. The composition ratio of the (meth) acrylic polymer chain bonded to the SEBS triblock polymer chain calculated from the reaction rate to the (meth) acrylic polymer (mass basis) was MMA: MHMA: st 45.2: 48.7: 6.0, the content of the (meth) acrylate-derived unit was 3.7% by mass, the content of the cyclic structure unit was 82.6% by mass, and the content of the styrene-derived unit was 6.9% by mass. When a part of the reaction solution was taken out and subjected to a filtration test, the pressure of the filter was observed to be increased. The resulting resin composition (D-14) had a glass transition temperature of 158 ℃ and a chloroform-insoluble content of 10.4%.

[ Table 1]

[ Table 2]

[ Table 3]

The results of the examples and comparative examples are shown in tables 1 to 3. The resin composition A-3 of comparative example 1, in which no ring structure was introduced into the graft chain, had a low glass transition temperature and low heat resistance. In addition, even when the ring structure was introduced, the resin composition B-1 of comparative example 2, the resin composition B-2 of comparative example 3, the resin composition B-3 of comparative example 5, and the resin composition B-4 of comparative example 8, which did not contain the graft copolymer, had low impact strength (energy to failure) and poor mechanical strength. The resin compositions A-4 and C-3 and D-9 and D-10 and D-14 in comparative examples 4 and 6 and 7 and 9 and 10 and 11 and 12 respectively had a cyclic structure unit in the graft chain, and the proportion of the (meth) acrylate unit in the graft chain was less than 45 to 98% by mass, and thus the glass transition temperature was low and the heat resistance was poor, the impact strength (failure energy) was low and the mechanical strength was poor, or a gel was formed during the production to contain a large amount of foreign matter. On the other hand, the resin compositions of examples 1 to 15 have excellent transparency, mechanical strength and heat resistance in a well-balanced manner, and the generation of gelled products is small.

Industrial applicability of the invention

According to the present invention, since a copolymer and a resin composition excellent in transparency, mechanical strength and heat resistance can be obtained, when they are used for an optical film or the like, an excellent polarizer protective film, a polarizing plate, an image display device or the like can be produced.

Claims

1. A copolymer comprising: a polymer chain (A) having a unit derived from a diene and/or an olefin, and a polymer chain (B) having a unit derived from a (meth) acrylic monomer and a unit having a ring structure in the main chain,

the content ratio of the unit derived from the (meth) acrylate in the polymer chain (B) is 45 to 98% by mass,

the copolymer has a glass transition temperature above 100 ℃ and below 100 ℃, respectively.

2. The copolymer according to claim 1, wherein the polymer chain (B) is a polymer chain grafted on the polymer chain (a).

3. The copolymer according to claim 1 or 2, wherein the ring structure is at least one selected from a lactone ring structure, a cyclic imide structure, and a cyclic anhydride structure.

4. The copolymer according to claim 1 or 2, wherein the ring structure is at least one selected from a lactone ring structure, a maleimide structure, a glutarimide structure, a maleic anhydride structure, and a glutaric anhydride structure.

5. The copolymer according to claim 1 or 2, wherein the ring structure is a lactone ring structure and/or a maleimide structure.

6. The copolymer according to claim 4, wherein the maleimide structure is a structure represented by the following formula (2),

in the formula (2), R⁴And R⁵Each independently represents a hydrogen atom or a methyl group, R⁶Represents a hydrogen atom or a substituent, X¹Represents an oxygen atom or a nitrogen atom, X¹When it is an oxygen atom, n1 is 0, X¹And n1 is 1 when it is a nitrogen atom.

7. The copolymer according to claim 1 or 2, wherein a total content ratio of the unit derived from the (meth) acrylic monomer and the unit having a ring structure in the main chain in the polymer chain (B) is 90% by mass or more.

8. The copolymer according to claim 1 or 2, wherein a content ratio of the unit having a ring structure in the main chain in the polymer chain (B) is 2% by mass or more and 50% by mass or less.

9. The copolymer according to claim 1 or 2, wherein the polymer chain (a) is a triblock copolymer.

10. The copolymer according to claim 1 or 2, wherein the polymer chain (a) contains a polymer block (a1) having units derived from a diene and/or an olefin and a polymer block (a2) having units derived from other unsaturated monomers.

11. The copolymer according to claim 10, wherein the polymer block (a2) is bonded to both sides of the polymer block (a1) of the polymer chain (a).

12. The copolymer according to claim 10, wherein the polymer block (a1) further has units derived from other unsaturated monomers, in addition to units derived from dienes and/or olefins.

13. The copolymer according to claim 10, wherein the content ratio of the units derived from a diene and/or an olefin in 100% by mass of the polymer block (a1) is 50% by mass or more.

14. The copolymer of claim 10, wherein the polymer block (a2) has units derived from an aromatic vinyl monomer.

15. The copolymer according to claim 14, wherein the content ratio of the unit derived from an aromatic vinyl monomer in 100% by mass of the polymer block (a2) is 70% by mass or more.

16. The copolymer according to claim 10, wherein the content ratio of the polymer block (a2) in the polymer chain (A) is 10 to 55 mass%.

17. The copolymer according to claim 1 or 2, wherein the weight average molecular weight of the polymer chain (a) is 0.1 to 30 ten thousand.

18. The copolymer according to claim 1 or 2, wherein a content ratio of the unit having a ring structure in the main chain in the polymer is 1 mass% or more and 60 mass% or less.

19. A resin composition comprising the copolymer according to any one of claims 1 to 18 and a (meth) acrylic polymer.

20. The resin composition according to claim 19, wherein the (meth) acrylic polymer has the unit derived from a (meth) acrylic monomer.

21. The resin composition according to claim 19, wherein the (meth) acrylic polymer has a unit having a ring structure in the main chain.

22. The resin composition of claim 19, wherein the resin composition has a glass transition temperature above 100 ℃ and below 100 ℃, respectively.

23. The resin composition according to claim 19, wherein the resin composition has a glass transition temperature of 100 ℃ or higher and less than 300 ℃ and-100 ℃ or higher and less than 100 ℃, respectively.

24. The resin composition according to claim 19, wherein the resin composition has a glass transition temperature of 120 ℃ or more and less than 180 ℃ and-80 ℃ or more and less than 10 ℃, respectively.

25. The resin composition according to claim 19, wherein an insoluble content in chloroform of the resin composition is 10% by mass or less.

26. The resin composition according to claim 19, wherein a content ratio of the copolymer is 1% by mass or more and 90% by mass or less in 100% by mass of a solid content of the resin composition.

27. The resin composition according to claim 19, wherein a content ratio of the polymer chain (a) of the copolymer is 0.5% by mass or more and 50% by mass or less in 100% by mass of a solid content of the resin composition.

28. The resin composition according to claim 19, wherein the weight average molecular weight of the resin composition is 0.2 to 100 ten thousand.

29. The resin composition according to claim 19, wherein a weight average molecular weight of the resin composition is 1.1 times or more and 20 times or less a weight average molecular weight of the polymer chain (a) of the copolymer.

30. The resin composition according to claim 19, wherein the difference between the refractive index of the resin composition and the refractive index of the polymer chain (a) of the copolymer is less than 0.1.

31. The resin composition according to claim 19, wherein the resin composition exhibits a sea-island structure in which island size is 10nm or more and 500nm or less when formed into an unstretched film having a thickness of 160 μm.

32. The resin composition according to claim 19, wherein the resin composition has a breaking energy of 20mJ or more when it is formed into an unstretched film having a thickness of 160 μm.

33. A molded article comprising the copolymer according to any one of claims 1 to 18 or the resin composition according to any one of claims 19 to 32.

34. The molded body according to claim 33, wherein the shape of the molded body is plate-like, sheet-like, granular, powdery, massive, particle agglomerate-like, spherical, ellipsoid-like, lenticular, cubic, columnar, rod-like, conical, cylindrical, needle-like, fibrous, hollow-filamentous or porous.

35. A film comprising the copolymer according to any one of claims 1 to 18 or the resin composition according to any one of claims 19 to 32.

36. An optical film comprising the copolymer according to any one of claims 1 to 18 or the resin composition according to any one of claims 19 to 32.

37. The optical film according to claim 36, wherein the optical film is a protective film for optics, a polarizer protective film, a viewing angle compensation film, a light diffusion film, a reflection film, an antireflection film, an antiglare film, a brightness enhancement film, a conductive film for a touch panel, or a retardation film.

38. An optical film as recited in claim 36, wherein the optical film has a thickness of from 5 μm to 350 μm.

39. An optical film as recited in claim 36, wherein the optical film has a total light transmission of 70% or more.

40. An optical film as recited in claim 36, wherein the optical film has a haze of 5.0% or less.

41. An optical film as recited in claim 36, wherein the optical film has an internal haze of 5.0% or less.

42. The optical film according to claim 36, wherein the in-plane retardation Re with respect to light having a wavelength of 589nm is 0nm or more and 1000nm or less.

43. The optical film according to claim 36, wherein a retardation Rth in a thickness direction with respect to a light having a wavelength of 589nm is from-1000 nm to 1000 nm.

44. A polarizing plate comprising the optical film according to any one of claims 36 to 43.

45. An image display device comprising the optical film according to any one of claims 36 to 43.

46. A method for producing the copolymer according to any one of claims 1 to 18, comprising the steps of,

47. A method for producing the copolymer according to any one of claims 1 to 18, comprising the steps of,

48. The method of preparing a copolymer of claim 46, wherein the method further comprises: and a step of filtering the resin solution obtained in the polymerization step.

49. The method of preparing a copolymer according to claim 47, wherein the method further comprises: and a step of filtering the resin solution obtained in the ring structure forming step.