JP2020117604A - Resin composition and method for producing the same - Google Patents

Abstract

To provide a resin composition that makes it possible to prepare a negative retardation film having excellent mechanical strength.SOLUTION: A resin composition contains a polymer chain (A) having a diene- and/or olefin-derived unit, and a polymer chain (B) having a (meth) acrylic monomer-derived unit (b1) and a unit (b2) having a ring structure in the main chain, the resin composition having a stress optical coefficient Cr of -25.0×10Paor more to -4.0×10Paor less.SELECTED DRAWING: None

Description

The present invention relates to a resin composition and a method for producing the resin composition. Specifically, a polymer having a polymer chain (A) having a unit derived from a diene and/or an olefin, a unit (b1) derived from a (meth)acrylic monomer, and a unit (b2) having a ring structure in its main chain. The present invention relates to a resin composition containing a chain (B) and a method for producing the resin composition.

A stretched film obtained by stretching a resin film is widely used in the image display field. A retardation film is one type of such a stretched film, and a negative retardation film is one type of retardation film. Negative retardation films are widely used in image display devices such as liquid crystal display devices (LCD). As a negative retardation film, for example, in Patent Document 1, a stretched film obtained by stretching a resin composition having a (meth)acrylic acid ester unit, an aromatic vinyl compound unit, and an aromatic maleimide unit as constitutional units. Is disclosed.

JP, 2011-38053, A

However, the mechanical strength of the stretched film obtained by stretching the resin composition of Patent Document 1 has been required to be further improved.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a resin composition capable of producing a negative retardation film having excellent mechanical strength.

As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that a polymer chain (A) having a diene- and/or olefin-derived unit in a resin composition and a (meth)acrylic monomer-derived polymer chain. By containing the unit (b1) and the polymer chain (B) having the unit (b2) having a ring structure in the main chain, a negative retardation film having excellent mechanical strength could be produced.
That is, the present invention includes the following inventions.

[1] A polymer chain (A) having a unit derived from a diene and/or an olefin, a polymer chain (b1) derived from a (meth)acrylic monomer, and a unit (b2) having a ring structure in its main chain. A resin composition containing (B), wherein the resin composition has a stress optical coefficient Cr of −25.0×10 ⁻¹¹ Pa ⁻¹ or more and −4.0×10 ⁻¹¹ Pa ⁻¹ or less. A resin composition comprising:
[2] A stretched film having a thickness of 40 μm obtained by performing free-end uniaxial stretching of an unstretched film obtained from the resin composition at a temperature 4° C. higher than the glass transition temperature of the resin composition at a stretch ratio of 2 times. The resin composition according to [1], which has a folding endurance of 10 times or more in a MIT test based on JIS P 8115 in the unstretched direction.
[3] A stretched film obtained by subjecting an unstretched film obtained from the resin composition to free-end uniaxial stretching at a stretching ratio of 2 at a temperature 4° C. higher than the glass transition temperature of the resin composition, and having a wavelength of 589 nm. The resin composition according to [1] or [2], which has an in-plane retardation Re of 30 nm or more per 40 μm in thickness with respect to light.
[4] The resin composition according to any one of [1] to [3], which has a melt flow rate of 10 to 40 g/10 minutes measured at a temperature of 240° C. and a load of 10 kgf according to JIS K 7210 B method. ..
[5] The method according to any one of [1] to [4], further including a (meth)acrylic polymer (Q) having a unit derived from a (meth)acrylic monomer and a unit having a ring structure in the main chain. Resin composition.
[6] The polymer chain (A) has a polymer block (a1) having a diene and/or olefin-derived unit and a polymer block (a2) having an aromatic vinyl monomer-derived unit [ The resin composition according to any one of 1] to [5].
[7] The resin composition according to [6], wherein the polymer chain (B) is grafted onto the polymer block (a1) of the polymer chain (A).
[8] The polymer chain (B) according to any one of [1] to [7], further including a vinyl monomer-derived unit (b3) copolymerizable with the (meth)acrylic monomer. Resin composition.
[9] A film containing the resin composition according to any one of [1] to [8].
[10] A method for producing a resin composition in which a (meth)acrylic monomer is polymerized in the presence of a polymer having units derived from a diene and/or an olefin, wherein the stress optical coefficient Cr of the resin composition is manufacturing method of -25.0 × 10 ^-11 Pa ^-1 or -4.0 × 10 ^-11 Pa ^-1 or less is a resin composition.

The resin composition of the present invention comprises a polymer chain (A) having a unit derived from a diene and/or an olefin, a unit (b1) derived from a (meth)acrylic monomer, and a unit (b2) having a ring structure in the main chain. By containing the polymer chain (B) having a), a negative retardation film having excellent mechanical strength (a film having a negative retardation Rth in the thickness direction described later) can be produced. Further, when the in-plane retardation Re is made sufficiently large when a film is produced using the above resin composition, a retardation film excellent in color tone compensation, viewing angle compensation and the like can be obtained.

The resin composition of the present invention comprises a polymer chain (A) having a unit derived from a diene and/or an olefin, a unit (b1) derived from a (meth)acrylic monomer, and a unit (b2) having a ring structure in the main chain. And a polymer chain (B) having

1. Polymer chain (A)
The polymer chain (A) has a unit derived from a diene and/or an olefin. From the viewpoint of improving the mechanical strength of the resin composition, the resin composition preferably contains the polymer chain (A) in an amount of 5 to 50% by mass, more preferably 7 to 40% by mass, and 10 to 30% by mass. It is further preferable that the content is included by mass%.

As the diene forming the unit derived from diene, 1,3-butadiene (also known as butadiene), 2-methyl-1,3-butadiene (also known as isoprene), 1,3-pentadiene, 1,4-pentadiene, 1 Alkadienes such as 1,5-hexadiene and 2,5-dimethyl-1,5-hexadiene (also known as diisobutene) are preferably used, and among them, 1,3-butadiene, 2-methyl-1,3-butadiene and 1,3. More preferred are conjugated dienes such as pentadiene.
Examples of the olefin forming the olefin-derived unit include monoolefins (alkenes such as ethylene, propylene, 1-butene, isobutene, 2-methyl-1-butene, 3-methyl-1-butene, 1-tetradecene, 1-octadecene. (Also referred to as )) are preferably used, and α-olefins, which are alkenes having a carbon-carbon double bond in the α-position, are more preferable. The carbon number of these dienes and olefins is preferably 2 or more, more preferably 3 or more, preferably 20 or less, more preferably 10 or less, and further preferably 6 or less.

The diene and/or olefin derived unit is defined as the unit formed by the polymerization of the diene and/or olefin. The olefin-derived units are not limited to those actually formed by homopolymerization or copolymerization of olefins as long as the same structure is formed, and may be formed by hydrogenating a diene-derived unit (note that In the present specification, “homopolymerization or copolymerization” is referred to as “homopolymer/copolymerization”, and “homopolymer or copolymer” is referred to as “(homopolymer/co)polymer”. May be written).

The polymer chain (A) preferably contains a polymer block (a1) having a diene and/or olefin-derived unit, and a polymer block (a1) having a diene and/or olefin-derived unit and an aromatic vinyl unit. It is more preferable to have a polymer block (a2) having a monomer-derived unit. The mechanical strength is increased by including the polymer chain (A) having the polymer block (a1) functioning as a soft component and the polymer block (a2) functioning as a hard component, and such a resin composition has high mechanical strength. It has strength (for example, impact resistance (falling ball strength)). In addition, the transparency and heat resistance are enhanced by including the polymer chain (B), and the resin composition including the polymer chain (A) and the polymer chain (B) has high transparency and high mechanical strength ( For example, both impact resistance (falling ball strength) can be achieved. The mechanical strength is not a physical property of the resin composition but a physical property of a molded article such as a film formed from the resin composition. In the present specification, the mechanical strength is simply referred to as “mechanical strength” or “mechanical properties of film”. Sometimes referred to as "intensity".

The content ratio of the diene and/or olefin-derived units in the polymer chain (A) is preferably 40% by mass or more, more preferably 50% by mass or more, and further preferably 60% by mass or more. The upper limit is not particularly limited, and is preferably 90% by mass or less, for example.

As the diene forming the diene-derived unit and the olefin forming the olefin-derived unit of the polymer block (a1), those mentioned above may be used. In the polymer block (a1), as a unit derived from diene and/or olefin, a unit derived from butadiene, a unit derived from isoprene, a unit derived from ethylene, a unit derived from propylene, a unit derived from 1-butene, and a unit derived from isobutene It is preferable that at least one selected from the units is contained.

Examples of the polymer block (a1) include olefin (homo/co) polymers such as polyethylene, polypropylene, polybutene-1, ethylene-propylene copolymer, and ethylene-butene copolymer; polyisoprene, polybutadiene, isoprene- Diene (homo/co)polymers such as butadiene copolymers; copolymers of olefins and dienes such as ethylene-propylene-diene copolymers and isobutene-isoprene copolymers. The olefin (homo/co) polymer is preferably an α-olefin (homo/co) polymer, the diene (homo/co) polymer is preferably a conjugated diene (homo/co) polymer, and the olefin/diene co-polymer is As the polymer, a copolymer of α-olefin and conjugated diene is preferable. Among these, copolymers of α-olefin and conjugated diene such as polyisoprene and isobutene-isoprene copolymer, and polyethylene and polypropylene are more preferable.

The polymer block (a1) may have a unit derived from another unsaturated monomer in addition to the unit derived from a diene and/or an olefin. 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; (meth)acrylic acid, maleic anhydride, (meth ) Methyl acrylate, unsaturated carboxylic acids such as ethyl (meth)acrylate and esters thereof; vinyl silanes such as vinyltrimethoxysilane and γ-(meth)acryloyloxypropylmethoxysilane; and aromatic vinyl monomers Can be mentioned.

The aromatic vinyl monomer 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, vinyltoluene, methoxystyrene, α-methylstyrene, α-hydroxymethylstyrene, α-hydroxyethyl. Styrene type monomers such as styrene; polycyclic aromatic hydrocarbon ring vinyl monomers such as 2-vinylnaphthalene; aromatic heterocyclic vinyl units such as N-vinylcarbazole, 2-vinylpyridine, vinylimidazole, vinylthiophene, etc. Examples thereof include a polymer. Of these, styrene-based monomers are preferable. The styrene-based monomer includes not only styrene but also a styrene derivative in which an arbitrary substituent is bonded to the polymerizable double bond carbon or benzene ring of styrene, and the substituent is an alkyl group, an alkoxy group, Examples thereof include a hydroxy group, a halogen group, an amino group, a nitro group and a sulfo group. The alkyl group and alkoxy group bonded to styrene preferably have 1 to 4 carbon atoms, and more preferably 1 to 2 carbon atoms. In the alkyl group and alkoxy group bonded to styrene, at least a part of hydrogen atoms is a hydroxy group or a halogen atom. It may be substituted with a group. From the viewpoint of reducing the coloring of the resin composition, the styrene-based monomer preferably has no amino group. Further, the styrene-based monomer is preferably unsubstituted styrene having no substituent bonded to the polymerizable double bond carbon of styrene or the benzene ring.

The polymer block (a1) may be a copolymer of these other unsaturated monomers and a diene and/or olefin. As the other unsaturated monomer, an aromatic vinyl monomer is preferable. When the copolymer of the aromatic vinyl monomer and the diene and/or the olefin is used as the polymer block (a1), the transparency is easily increased. For example, even when there is a large difference in refractive index between the polymer chain (A) and the polymer chain (B), it becomes easy to increase transparency.

When the polymer block (a1) has a unit derived from an aromatic vinyl monomer, the content ratio of the unit derived from an aromatic vinyl monomer is 1% by mass or more in the polymer block (a1). It is preferably 2% by mass or more, more preferably 3% by mass or more, further preferably 50% by mass or less, more preferably 40% by mass or less, still more preferably 30% by mass or less. In this case, the total content of the units derived from the diene and/or olefin and the units derived from the aromatic vinyl monomer in the polymer block (a1) is preferably 70% by mass or more, and 80% by mass or more. Is more preferable, and 90% by mass or more is further preferable. The polymer block (a1) may consist essentially of units derived from a diene and/or olefin and units derived from an aromatic vinyl monomer, for example, the total content of these units is 99% by mass. It may be more than.

When the polymer block (a1) has a unit derived from another unsaturated monomer in addition to a unit derived from a diene and/or an olefin, the polymer block (a1) is formed from these monomers. It is preferable that it is a random copolymer of.

The polymer block (a1) preferably contains a diene- and/or olefin-derived unit as a main component, and the content ratio of the diene- and/or olefin-derived unit is 50% in 100% by mass of the polymer block (a1). It is preferably at least mass%, more preferably at least 60 mass%, even more preferably at least 70 mass%. The polymer block (a1) may be substantially composed only of units derived from a diene and/or olefin, and for example, the units derived from a diene and/or olefin may be 99% by mass or more.

The polymer chain (A) may have a polymer block (a2) having a unit derived from an aromatic vinyl monomer. Examples of the aromatic vinyl monomer forming the polymer block (a2) include the aromatic vinyl monomers exemplified in the polymer block (a1), and among them, the styrene-based monomer is preferable.

The polymer block (a2) may have a unit derived from another unsaturated monomer in addition to the unit derived from an aromatic vinyl monomer. 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; (meth)acrylic acid, maleic anhydride, (meth ) Unsaturated carboxylic acids such as methyl acrylate and ethyl (meth)acrylate and esters thereof; vinyl silanes such as vinyltrimethoxysilane and γ-(meth)acryloyloxypropylmethoxysilane. The polymer block (a2) may be a copolymer of these other unsaturated monomers and an aromatic vinyl monomer (particularly a random copolymer). The content ratio of the diene- and/or olefin-derived units in the polymer block (a2) is preferably 1% by mass or less, and the polymer block (a2) has a diene- and/or olefin-derived unit. Not preferably.

The polymer block (a2) preferably contains a unit derived from an aromatic vinyl monomer as a main component. Specifically, the content ratio of the unit derived from the aromatic vinyl monomer in the polymer block (a2) is preferably 70% by mass or more, more preferably 80% by mass or more, and further preferably 90% by mass or more. preferable. The polymer block (a2) may be substantially composed only of units derived from an aromatic vinyl monomer, for example, the content ratio of the units derived from an aromatic vinyl monomer is 99% by mass or more. Good.

Examples of the polymer chain (A) composed of the polymer block (a1) and the polymer block (a2) include, for example, styrene-butadiene block copolymer, styrene-butadiene-styrene block copolymer, and styrene-butadiene-. Hydrogenated styrene block copolymer (for example, styrene-ethylene/butylene-styrene block copolymer (SEBS), styrene-butadiene/butylene-styrene block copolymer), styrene-isoprene block copolymer, styrene- Examples thereof include isoprene-styrene block copolymers and hydrogenated products of styrene-isoprene-styrene block copolymers (for example, styrene-ethylene/propylene-styrene block copolymers (SEPS)). Further, among these block copolymers, those in which the butadiene block is a butadiene/styrene block and those in which the isoprene block is an isoprene/styrene block can be mentioned. In the above notation, each block is divided by "-", and the notation of "/" in each block represents a monomer unit constituting the block.

The polymer chain (A) is preferably one in which the polymer blocks (a2) are bound to both sides of the polymer block (a1). Thereby, the polymer chain (A) functions as an elastomer, and the mechanical strength of the film can be further increased. In this case, the polymer chain (A) may be a triblock copolymer, a multiblock copolymer, a radial block copolymer, or the like. From the viewpoint of easy control of characteristics, a triblock copolymer is preferable. Examples of such a copolymer include a styrene-butadiene-styrene block copolymer and a hydrogenated product thereof, and a styrene-isoprene-styrene block copolymer and a hydrogenated product thereof.

The content ratio of the polymer block (a2) in the polymer chain (A) may be 0% by mass (consisting only of the polymer block (a1)), but is preferably 5% by mass or more and 10% by mass or more. Is more preferable, 15 mass% or more is further preferable, 55 mass% or less is preferable, 50 mass% or less is more preferable, and 45 mass% or less is further preferable. Thereby, the polymer chain (A) has a soft component and a hard component in a well-balanced manner, and it becomes easy to increase the mechanical strength of the film. 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 95 The content is preferably not more than 90% by mass, more preferably not more than 90% by mass, further preferably not more than 85% by mass. The content ratio of the unit derived from the aromatic vinyl monomer in the polymer chain (A) may be 0% by mass, but is preferably 5% by mass or more, more preferably 10% by mass or more, and 15% by mass. % Or more, more preferably 55% by mass or less, further preferably 50% by mass or less, and further preferably 45% by mass or less.

The weight average molecular weight of the polymer chain (A) is preferably 10 thousand or more, more preferably 50 thousand or more, further preferably 10,000 or more, still more preferably 30,000 or more, and preferably 300,000 or less, It is more preferably 250,000 or less, still more preferably 200,000 or less. By setting the weight average molecular weight of the polymer chain (A) within such a range, it becomes easy to secure the mechanical strength of the film and enhance the moldability of the resin composition.

2. Polymer chain (B)
The polymer chain (B) includes a unit (b1) derived from a (meth)acrylic-based monomer (hereinafter sometimes referred to as “(meth)acrylic unit (b1)”) and a unit having a ring structure in the main chain ( b2) (hereinafter sometimes referred to as “ring structural unit (b2)”). When the polymer chain (B) has the ring structural unit (b2), the heat resistance of the film can be increased. Further, improvement in solvent resistance, surface hardness, adhesiveness, barrier property against oxygen and water vapor, and various optical properties can be expected. When the resin composition is formed into a film or sheet, it is possible to improve dimensional stability and shape stability. Further, by stretching an unstretched film formed from the resin composition containing the polymer chain (B), it is possible to develop a retardation due to the ring structure of the polymer chain (B).

In the present specification, the (meth)acrylic monomer is a monomer containing an acrylic group in which a hydrogen atom or an alkyl group (preferably an alkyl group having 1 to 4 carbon atoms) is bonded to the α-position and/or the β-position. Used in the meaning of, at least a part of the hydrogen atom of the alkyl group may be substituted with a hydroxy group or a halogen group. The (meth)acrylic monomer preferably means a monomer having an acrylic group or a methacrylic group. The (meth)acrylic monomers include (meth)acrylic acid (that is, free acid) and its derivatives, and the derivatives include esters, salts, acid amides and the like.

As the (meth)acrylic monomer, a (meth)acrylic acid ester is preferable. The (meth)acrylic acid ester is a (meth)acrylic acid ester in which a linear, branched or cyclic aliphatic hydrocarbon group or aromatic hydrocarbon group is bonded to the oxygen atom of the ester bond of (meth)acrylic acid. Are listed.

Examples of the (meth)acrylic acid ester having a linear or branched aliphatic hydrocarbon group include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, and (meth)acrylic. Isopropyl acid, n-butyl (meth)acrylate, isobutyl (meth)acrylate, sec-butyl (meth)acrylate, tert-butyl (meth)acrylate, pentyl (meth)acrylate, amyl (meth)acrylate , Isoamyl (meth)acrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, decyl (meth)acrylate, (meth ) Dodecyl acrylate, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, heptadecyl (meth)acrylate, octadecyl (meth)acrylate, and other alkyl (meth)acrylates. The alkyl group of the alkyl (meth)acrylate is preferably a C1-18 alkyl group, more preferably a C1-12 alkyl group, and even more preferably a C1-6 alkyl group. In addition, in this specification, description with "C1-18" or "C1-12" means "C1-18" and "C12-12", respectively.

Examples of the (meth)acrylic acid ester having a cyclic aliphatic hydrocarbon group include (meth)acrylic acid cyclopropyl, (meth)acrylic acid cyclobutyl, (meth)acrylic acid cyclopentyl, (meth)acrylic acid cyclohexyl, and the like (meth ) Cycloalkyl 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 C4-12 cycloalkyl group, and even more preferably a C5-10 cycloalkyl group.

Examples of the (meth)acrylic acid ester having an aromatic hydrocarbon group include phenyl (meth)acrylate, tolyl (meth)acrylate, xylyl (meth)acrylate, naphthyl (meth)acrylate, and binaphthyl (meth)acrylate. Aryl (meth)acrylates such as anthryl (meth)acrylate; aralkyl (meth)acrylates such as benzyl (meth)acrylate; aryloxyalkyl (meth)acrylates such as phenoxyethyl (meth)acrylate; Can be mentioned. The aryl group of the aryl (meth)acrylate is preferably a C6-20 aryl group, and more preferably a C6-14 aryl group. The aralkyl group of aralkyl (meth)acrylate is preferably a C6-10 aryl C1-4 alkyl group. The aryloxyalkyl group of the aryloxyalkyl (meth)acrylate is preferably a C6-10 aryloxy C1-4 alkyl group, and more preferably a phenoxy C1-4 alkyl group.

The (meth)acrylic acid ester may have a substituent such as a hydroxy group, an amino group, a halogen group, an alkoxy group and an epoxy group. Particularly in the (meth)acrylic acid ester having a linear or branched aliphatic hydrocarbon group, the aliphatic hydrocarbon group preferably has a hydroxy group, an amino group, a halogen group, an alkoxy group, an epoxy group, or the like. Examples of such (meth)acrylic acid ester include hydroxyalkyl (meth)acrylate such as 2-hydroxyethyl (meth)acrylate; chloromethyl (meth)acrylate, (meth)acrylic acid 2-chloroethyl ( Examples thereof include an alkyl halide of (meth)acrylate; an alkoxyalkyl (meth)acrylate such as 2-methoxyethyl (meth)acrylate; an epoxyalkyl (meth)acrylate such as glycidyl (meth)acrylate. The alkyl group of hydroxyalkyl (meth)acrylate and epoxyalkyl (meth)acrylate is preferably a C1-12 alkyl group, and more preferably a C1-6 alkyl group. The alkoxyalkyl group of the alkoxyalkyl (meth)acrylate is preferably a C1-12 alkoxyC1-12 alkyl group, the alkoxy group is more preferably C1-6, and the alkyl group is more preferably C1-6.

Examples of the (meth)acrylic monomer also include monomers exemplified as the (meth)acrylic monomer A and the (meth)acrylic monomer B having a protonic hydrogen atom-containing group described later. ..

The ring structure of the main chain of the polymer chain (B) may include a part or all of the (meth)acrylic monomer in the ring structure, and is introduced separately from the (meth)acrylic monomer. It may have a ring structure. In this way, the components necessary for forming a ring structure in the main chain of the polymer chain (also referred to as a ring structure forming monomer) include a part or all of the (meth)acrylic monomer in the ring structure. In such a case, for example, two carboxylic acid groups of adjacent (meth)acrylic units (b1) may be linked by acid anhydride, imidization, or the like. When one of the adjacent (meth)acrylic units (b1) has a protic hydrogen atom-containing group such as a hydroxy group or an amino group, the protic hydrogen atom of the one (meth)acrylic unit (b1) The ring structure can also be formed by condensing the containing group and the carboxylic acid group of the other (meth)acrylic unit (b1). When the ring structure is introduced separately from the (meth)acrylic unit (b1), for example, a (meth)acrylic monomer and a monomer having a polymerizable double bond in the ring structure may be copolymerized. Good.

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, etc., preferably a 5-membered ring structure or a 6-membered ring structure.

The ring structure, from the viewpoint of heat resistance of the resin composition, a lactone ring structure, a lactam ring structure, a cyclic imide structure (for example, a succinimide structure, a glutarimide structure, etc.), a cyclic anhydride structure (for example, a succinic anhydride structure, Preferable examples thereof include a glutaric anhydride structure). Only one type of these ring structures may be contained in the main chain of the polymer chain (B), or two or more types may be contained therein. Among these, a cyclic imide structure is preferable, and a succinimide structure is more preferable.

When the polymer chain (B) has a lactone ring structure or a lactam ring structure as the main ring structure, the number of ring members in the lactone ring structure or the lactam ring structure is not particularly limited, and may be, for example, a 4-membered ring to an 8-membered ring. If The lactone ring structure or the lactam 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.

Examples of the lactone ring structure include the structure disclosed in JP-A-2004-168882 and the like. However, the introduction of the lactone ring structure is easy, and specifically, the precursor (pre-lactone cyclization For the reasons such as high polymerization yield of (polymer), high lactone ring content in the cyclocondensation reaction of the precursor, and the ability to use a polymer having a unit derived from (meth)acrylate as the precursor, The structure represented by formula (1a) is preferably shown. As the lactam ring structure, a structure represented by the following formula (1b) is preferably shown. In the following formula (1a) or the following formula (1b), R ¹ , R ² and R ³ each independently represent a hydrogen atom or a substituent.

Examples of the substituent of R ¹ , R ² and R ^{3 in} the formulas (1a) and (1b) include an organic residue such as a hydrocarbon group. For example, C1-20 which may have a substituent. And the hydrocarbon group. Examples of the hydrocarbon group include saturated or unsaturated linear, branched or cyclic aliphatic hydrocarbon groups and aromatic hydrocarbon groups. Examples of the aliphatic hydrocarbon group include a C1-20 alkyl group such as a methyl group, an ethyl group, an n-propyl group, and an isopropyl group (preferably a C1-10 alkyl group, more preferably a C1-6 alkyl group). Group); C2-20 alkenyl group such as ethenyl group and propenyl group (preferably C2-10 alkenyl group, more preferably C2-6 alkenyl group); C3-20 cycloalkyl such as cyclopentyl group and cyclohexyl group A group (preferably a C4-12 cycloalkyl group, more preferably a C5-8 cycloalkyl group) and the like can be mentioned. As the aromatic hydrocarbon group, for example, a C6-20 aryl group such as a phenyl group, a tolyl group, a xylyl group, a naphthyl group, and a biphenyl group (preferably a C6-14 aryl group, more preferably a C6-10 aryl group). Aryl group); C7-20 aralkyl group such as benzyl group and phenylethyl group (preferably C7-15 aralkyl group, more preferably C7-11 aralkyl group) and the like. These hydrocarbon groups may contain an oxygen atom or a halogen atom. Specifically, one or more hydrogen atoms of the hydrocarbon group are selected from a hydroxy group, a carboxy group, an ether group and an ester group. It may be substituted with at least one type of group.

In the lactone ring structure of the formula (1a) or the lactam ring structure of the formula (1b), R ¹ and R ² are each independently a hydrogen atom or C ¹ from the viewpoint of easily obtaining a resin composition having excellent heat resistance. -20 alkyl group, R ³ is preferably a hydrogen atom or a methyl group, R ¹ and R ² are each independently a hydrogen atom or a methyl group, and R ³ is a hydrogen atom or a methyl group. Is more preferable.

Protonic hydrogen atom-containing group of a unit derived from (meth)acrylic monomer A having a protic hydrogen atom-containing group such as hydroxy group or amino group and a unit derived from (meth)acrylic monomer A A lactone ring structure and/or a lactam ring structure can be introduced into the polymer chain (B) by cyclocondensation with an ester group of a unit derived from an adjacent (meth)acrylic acid ester. A (meth)acrylic monomer A having a protic hydrogen atom-containing group such as a hydroxy group or an amino group is essential as a polymerization component, and the (meth)acrylic monomer B includes the monomer A. To do. The monomer B may or may not match the monomer A. When the monomer B matches the monomer A, the monomer A is homopolymerized.

Examples of the (meth)acrylic monomer A having a protic hydrogen atom-containing group include a (meth)acrylic monomer A1 having a hydroxy group and a (meth)acrylic monomer A2 having an amino group. ..

Examples of the (meth)acrylic monomer A1 having a hydroxy group include 2-(hydroxymethyl)acrylic acid, 2-(hydroxyethyl)acrylic acid, and alkyl 2-(hydroxymethyl)acrylate (for example, 2-(hydroxy)). Methyl)methyl acrylate, ethyl 2-(hydroxymethyl)acrylate, isopropyl 2-(hydroxymethyl)acrylate, n-butyl 2-(hydroxymethyl)acrylate, t-butyl 2-(hydroxymethyl)acrylate) , Alkyl 2-(hydroxyethyl)acrylate (eg, methyl 2-(hydroxyethyl)acrylate, ethyl 2-(hydroxyethyl)acrylate), and the like, and preferably a monomer having a hydroxyallyl moiety. Specific examples include 2-(hydroxymethyl)acrylic acid and alkyl 2-(hydroxymethyl)acrylate. Particularly preferred are methyl 2-(hydroxymethyl)acrylate and ethyl 2-(hydroxymethyl)acrylate.

Examples of the (meth)acrylic monomer A2 having an amino group include compounds in which the hydroxy group of the monomer A1 is changed to an amino group. When the polymer chain (B) has a lactone ring structure and/or a lactam ring structure, the (meth)acrylic monomer A serves as a ring structure-forming monomer.

The (meth)acrylic monomer B is preferably a monomer having a vinyl group and an ester group or a carboxy group, and examples thereof include (meth)acrylic acid and alkyl (meth)acrylate (for example, (meth)acrylic). Methyl acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, cyclohexyl (meth)acrylate, etc., aryl (meth)acrylate (For example, phenyl (meth)acrylate, benzyl (meth)acrylate, etc., alkyl 2-(hydroxyalkyl)acrylate (eg, methyl 2-(hydroxymethyl)acrylate, ethyl 2-(hydroxymethyl)acrylate) And the like, 2-(hydroxymethyl)alkyl acrylate and the like, 2-(hydroxyethyl)alkyl acrylate such as methyl 2-(hydroxyethyl)acrylate, and the like.

The polymer chain (B) may have only one type of lactone ring structure or lactam structure represented by formula (1a) or formula (1b), or may have two or more types.

When the polymer chain (B) has a succinic anhydride structure (that is, a structure derived from a maleic anhydride monomer) or a succinimide structure (that is, a structure derived from a maleimide monomer) as a ring structure of the main chain, succinic anhydride As the structure or the succinimide structure, a structure represented by the following formula (2) is preferably shown. In the following formula (2), R ⁴ and R ⁵ each independently represent a hydrogen atom or a methyl group, R ⁶ represents a hydrogen atom or a substituent, X ¹ represents an oxygen atom or a nitrogen atom, and X ¹ Is an oxygen atom, n1=0, and when X ¹ is a nitrogen atom, n1=1.

Examples of the substituent of R ^{6 in} formula (2) include an organic residue such as a hydrocarbon group, and examples thereof include a C1-20 hydrocarbon group which may have a substituent. Examples of the hydrocarbon group include saturated or unsaturated linear, branched or cyclic aliphatic hydrocarbon groups and aromatic hydrocarbon groups. Examples of the aliphatic hydrocarbon group include a C1-20 alkyl group such as a methyl group, an ethyl group, an n-propyl group, and an isopropyl group (preferably a C1-10 alkyl group, more preferably a C1-6 alkyl group). Group); C2-20 alkenyl group such as ethenyl group and propenyl group (preferably C2-10 alkenyl group, more preferably C2-6 alkenyl group); C3-20 cycloalkyl such as cyclopentyl group and cyclohexyl group A group (preferably a C4-12 cycloalkyl group, more preferably a C5-8 cycloalkyl group) and the like can be mentioned. As the aromatic hydrocarbon group, for example, a C6-20 aryl group such as a phenyl group, a tolyl group, a xylyl group, a naphthyl group, and a biphenyl group (preferably a C6-14 aryl group, more preferably a C6-10 aryl group). Aryl group); C7-20 aralkyl group such as benzyl group and phenylethyl group (preferably C7-15 aralkyl group, more preferably C7-11 aralkyl group) and the like. These hydrocarbon groups may have a substituent such as halogen.

When X ¹ is an oxygen atom, the ring structure represented by the formula (2) is a succinic anhydride structure. The succinic anhydride structure can be introduced into the polymer chain (B) by, for example, copolymerizing maleic anhydride and a (meth)acrylic monomer (for example, a (meth)acrylic acid ester). .. When the polymer chain (B) has a succinic anhydride structure, maleic anhydride serves as a ring structure-forming monomer.

When X ¹ is a nitrogen atom, the ring structure represented by the formula (2) is a succinimide structure. The succinimide structure can be introduced into the polymer chain (B) by, for example, copolymerizing an N-substituted maleimide and a (meth)acrylic monomer (for example, (meth)acrylic acid ester). Examples of the succinimide structure include an N-unsubstituted succinimide structure, an N-methylsuccinimide structure, an N-ethylsuccinimide structure, an N-cyclohexylsuccinimide structure, an N-phenylsuccinimide structure, an N-naphthylsuccinimide structure, and an N-benzylsuccinimide structure. A structure etc. are mentioned. As the maleimide giving the succinimide structure, N-unsubstituted maleimide, N-methylmaleimide, N-ethylmaleimide, N-cyclohexylmaleimide, N-phenylmaleimide, N-naphthylmaleimide, N-benzylmaleimide or the like is used. And is preferably at least one selected from the group consisting of N-cyclohexylmaleimide and N-phenylmaleimide. When the polymer chain (B) has a succinimide structure, the N-substituted maleimide serves as a ring structure forming monomer.

When the polymer chain (B) has a succinimide structure in which X ¹ is a nitrogen atom, R ⁴ and R ⁵ are hydrogen atoms and R ⁶ is a hydrogen atom because it is easy to obtain a resin composition having excellent heat resistance. It is preferably a C3-20 cycloalkyl group or a C6-20 aromatic group (aryl group, aralkyl group, etc.), R ⁴ and R ⁵ are hydrogen atoms, and R ⁶ is a cyclohexyl group or a phenyl group. More preferable.

The polymer chain (B) may have only one type of ring structure represented by the formula (2), or may have two or more types.

When the polymer chain (B) has a glutarimide structure or a glutaric anhydride structure as the main chain ring structure, the glutarimide structure or the glutaric anhydride structure is preferably a structure represented by the following formula (3). In the following formula (3), R ⁷ and R ⁸ each independently represent a hydrogen atom or an alkyl group, R ⁹ represents a hydrogen atom or a substituent, X ² represents an oxygen atom or a nitrogen atom, and X ² Is an oxygen atom, n2=0, and when X ² is a nitrogen atom, n2=1.

In formula (3), the alkyl group of R ⁷ and R ⁸ is preferably a linear or branched alkyl group, and examples thereof include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, and an n-butyl group. Group, isobutyl group, tert-butyl group, n-pentyl group, isopentyl group, n-hexyl group, isohexyl group, n-heptyl group, isoheptyl group, n-octyl group, 2-ethylhexyl group and the like C1-8 An alkyl group etc. are mentioned. In addition, R ⁷ and R ⁸ are each independently preferably a hydrogen atom or a C1-4 alkyl group, and more preferably a hydrogen atom or a methyl group, from the viewpoint of easily obtaining a resin composition having excellent heat resistance.

Examples of the substituent of R ^{9 in} the formula (3) include an organic residue such as a hydrocarbon group, and examples thereof include a C1-20 hydrocarbon group which may have a substituent. Examples of the hydrocarbon group include saturated or unsaturated linear, branched or cyclic aliphatic hydrocarbon groups and aromatic hydrocarbon groups. Examples of the aliphatic hydrocarbon group include a C1-20 alkyl group such as a methyl group, an ethyl group, an n-propyl group, and an isopropyl group (preferably a C1-10 alkyl group, more preferably a C1-6 alkyl group). Group); C2-20 alkenyl group such as ethenyl group and propenyl group (preferably C2-10 alkenyl group, more preferably C2-6 alkenyl group); C3-20 cycloalkyl such as cyclopentyl group and cyclohexyl group A group (preferably a C4-12 cycloalkyl group, more preferably a C5-8 cycloalkyl group) and the like can be mentioned. As the aromatic hydrocarbon group, for example, a C6-20 aryl group such as a phenyl group, a tolyl group, a xylyl group, a naphthyl group, and a biphenyl group (preferably a C6-14 aryl group, more preferably a C6-10 aryl group). Aryl group); C7-20 aralkyl group such as benzyl group and phenylethyl group (preferably C7-15 aralkyl group, more preferably C7-11 aralkyl group) and the like. These hydrocarbon groups may have a substituent such as halogen. Of these, R ⁹ is preferably an alkyl group, a cycloalkyl group, an aryl group, or an aralkyl group, from the viewpoint of easily obtaining a resin composition having excellent heat resistance, and a methyl group, a cyclohexyl group, A phenyl group or a tolyl group is more preferable.

When X ² is an oxygen atom, the ring structure represented by the formula (3) is a glutaric anhydride structure. The glutaric anhydride structure can be introduced into the polymer chain (B) by, for example, converting two carboxylic acid groups of adjacent (meth)acrylic monomer-derived units into an acid anhydride.

When X ² is a nitrogen atom, the ring structure represented by the formula (3) is a glutarimide structure. The glutarimide structure has, for example, imidization of two carboxylic acid groups of adjacent (meth)acrylic monomer-derived units, or (meth) with amide groups of adjacent (meth)acrylic acid amide-derived units. It can be introduced into the polymer chain (B) by cyclocondensation with an ester group of a unit derived from an acrylate ester. When the polymer chain (B) has a glutarimide structure, the (meth)acrylic monomer serves as a ring structure-forming monomer.

In the ring structure of the formula (3), when X ² has a glutarimide structure in which nitrogen atom is a nitrogen atom, R ⁷ and R ⁸ are each independently independent from the viewpoint that it is easy to obtain a resin composition having excellent heat resistance. More preferably, it is a hydrogen atom or a methyl group, R ⁹ is a methyl group, a cyclohexyl group, a phenyl group, or a tolyl group, and R ⁷ and R ⁸ are each independently a hydrogen atom or a methyl group; It is particularly preferable that ⁹ is a cyclohexyl group or a phenyl group.

The polymer chain (B) may have only one type of ring structure represented by formula (3), or may have two or more types.

Among the ring structures described above, from the viewpoint of imparting good surface hardness, solvent resistance, adhesiveness, barrier properties, and optical properties to the resin composition, the ring structure unit (b2) of the polymer chain (B) is , A lactone ring structure and/or a succinimide structure (structure derived from a maleimide monomer) are preferable, and a succinimide structure is more preferable.

The content of the main chain ring structural unit (b2) in the polymer chain (B) is not particularly limited, but the content of the ring structural unit (b2) in the polymer chain (B) is preferably 3% by mass or more, and 5 Mass% or more is more preferable, 10 mass% or more is further preferable, 40 mass% or less is preferable, 30 mass% or less is more preferable, and 20 mass% or less is further preferable. By adjusting the content ratio of the ring structure unit (b2) of the main chain in this manner, both heat resistance and mechanical strength can be imparted in a well-balanced manner. The content ratio of the ring structural unit (b2) explained here means the content ratio of the unit having a ring structure contained in the main chain of the polymer chain (B), and for example, the above formulas (1) to (3) Means the content ratio of the structure represented by.

The polymer chain (B) may further have a vinyl monomer-derived unit (b3) copolymerizable with the (meth)acrylic monomer. The vinyl monomer copolymerizable with the (meth)acrylic 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; styrene, Aromatic vinyl compounds such as vinyltoluene, methoxystyrene, α-methylstyrene and 2-vinylpyridine; vinylsilane such as vinyltrimethoxysilane and γ-(meth)acryloyloxypropylmethoxysilane. For example, when the polymer chain (B) has a unit derived from an aromatic vinyl monomer, it becomes easy to adjust the refractive index and the retardation property of the resin composition. For the details of the aromatic vinyl monomer, the description of the aromatic vinyl monomer of the polymer chain (A) is referred to. When the polymer chain (B) is formed of two or more kinds of monomer components, the polymer chain (B) is preferably a random copolymer.

The unit (b3) derived from the vinyl monomer copolymerizable with the (meth)acrylic monomer is, for example, preferably 10 to 60 parts by mass in 100 parts by mass of the polymer chain (B). ˜50 parts by mass is more preferred, and 20 to 40 parts by mass is even more preferred.

The resin composition of the present invention preferably contains a copolymer (P) containing a polymer chain (A) and a polymer chain (B). The copolymer (P) is a polymer chain (A2) having a polymer block (a1) having a diene and/or olefin-derived unit and a polymer block (a2) having an aromatic vinyl monomer-derived unit. ), and a polymer chain (B) having a unit (b1) derived from a (meth)acrylic monomer and a unit (b2) having a ring structure in the main chain. In the copolymer (P), the polymer chain (B) is preferably grafted onto the polymer chain (A), and the polymer chain (B) is grafted onto the polymer block (a1) of the polymer chain (A). It is more preferable that the polymer chain (B) is bonded to a unit derived from a diene and/or an olefin of the polymer block (a1). Further, the polymer chain (A) contained in the copolymer (P) may be a triblock copolymer, a multiblock copolymer, or a radial block copolymer. However, from the viewpoint of easy introduction of the polymer chain (B) into the copolymer (P), the polymer chain (A) contained in the copolymer (P) is a triblock copolymer. Is preferred. According to the glossary of the basic terms of polymer science by the International Union of Pure and Applied Chemistry (IUPAC) Nomenclature for Polymers, a grafted polymer is a "bonded to a main chain as a side chain in a polymer. When there are one or several types of blocks, and these side chains have different structural (chemical structure) or arrangement characteristics from the main chain, this polymer is referred to as a graft polymer." There is. The graft copolymer can be obtained by a known production method such as a chain transfer reaction method, a polymer initiator method, a coupling method, a macromonomer method or a surface graft method, and only one of these methods is adopted. Alternatively, a plurality of them may be used in combination. For details of these methods, reference can be made to the 6th edition of the Chemical Handbook (Applied Chemistry), edited by The Chemical Society of Japan.

When the polymer chain (B) is bonded to a diene- and/or olefin-derived unit of the polymer block (a1), the polymer chain (B) is a carbon atom of the main chain of the diene- and/or olefin-derived unit. Or may be bonded to a carbon atom of a hydrocarbon group bonded to the main chain as a substituent (side chain). The polymer chain (B) may be bonded to, for example, a double bond derived from a diene of the main chain of the copolymer block (a1), or may be bonded to a carbon atom adjacent to the double bond. Alternatively, the polymer chain (B) is bonded to a double bond derived from a diene bonded to the main chain of the copolymer block (a1) as a substituent (side chain), or to a carbon atom adjacent to the double bond. You may have.

3. Method for Producing Polymer Chain (A) and Copolymer (P) The method for producing the polymer chain (A) having a diene and/or olefin-derived unit is not particularly limited and may be a known method.

As described above, the resin composition of the present invention has a polymer chain having a polymer block (a1) having a diene- and/or olefin-derived unit and a polymer block (a2) having an aromatic vinyl monomer-derived unit. Containing (A) and a copolymer (P) having a polymer chain (B) having a unit (b1) derived from a (meth)acrylic monomer and a unit (b2) having a ring structure in the main chain. Is preferred. Below, an example of the manufacturing method of such a copolymer (P) is demonstrated.

The copolymer (P) is conveniently produced by addition-polymerizing the monomer component forming the polymer chain (B) to the polymer chain (A). Therefore, the copolymer (P) is a copolymer (a2) having a polymer block (a1) having a unit derived from a diene and/or an olefin and a polymer block (a2) having a unit derived from an aromatic vinyl monomer. Hereinafter, those obtained by polymerizing a monomer component containing a (meth)acrylic monomer in the presence of “raw material copolymer (P1)” are preferable. In the present specification, the "raw material copolymer (P1)" may be simply referred to as "copolymer (P1)". For details of the raw material copolymer (P1), refer to the above description of the polymer chain (A).

In the copolymer (P), the polymer chain (B) is preferably grafted on the polymer block (a1) of the polymer chain (A). Specifically, the polymer chain (B) is preferably bonded to the diene and/or olefin-derived unit of the polymer block (a1). In this case, the polymer chain (B) may be bonded to the carbon atom of the main chain of the unit derived from diene and/or olefin, and the carbon atom of the hydrocarbon group bonded to the main chain as a substituent (side chain). It may be bonded to an atom. The polymer chain (B) may be bonded to, for example, a double bond derived from a diene of the main chain of the copolymer block (a1), or may be bonded to a carbon atom adjacent to the double bond. Alternatively, the polymer chain (B) is bonded to a double bond derived from a diene bonded to the main chain of the copolymer block (a1) as a substituent (side chain), or to a carbon atom adjacent to the double bond. You may have.

As the raw material copolymer (P1), it is preferable to use one having an olefinic double bond amount of 0.030 mmol/g or more and 2.3 mmol/g or less. By using the raw material copolymer (P1) having an olefinic double bond amount of 0.030 mmol/g or more, it is easy to obtain the copolymer (P) having high transparency. On the other hand, by using the raw material copolymer (P1) having an olefinic double bond content of 2.3 mmol/g or less, it becomes easy to obtain the copolymer (P) in which gelation is less likely to occur. The olefinic double bond content of the copolymer (P1) is more preferably 0.040 mmol/g or more, further preferably 0.050 mmol/g or more, and particularly preferably 2.0 mmol/g or less. The olefinic double bond content of the copolymer (P1) can be determined by ¹ H-NMR measurement or iodometric titration method.

The copolymer (P) can be obtained by a production method including a step (polymerization step) of polymerizing a monomer component containing a (meth)acrylic monomer in the presence of the raw material copolymer (P1). it can. In the polymerization step, the polymer component (B) is formed by polymerizing the monomer component containing the (meth)acrylic monomer, and the raw material copolymer (P1) gives the polymer chain (A). A copolymer (P) in which the polymer chain (B) is bonded to the diene- and/or olefin-derived units of the polymer block (a1) of the polymer chain (A) is obtained. The raw material copolymer (P1) may be obtained by polymerizing the monomer components constituting the polymer block (a1) to form the polymer block (a1) and then in the presence of the polymer block (a1). It can be obtained by polymerizing the monomer components constituting the polymer block (a2).

In the polymerization step, the polymer chain (B) is bonded to the diene- and/or olefin-derived units of the polymer block (a1), so that the polymer block (a1) of the raw material copolymer (P1) is used in the polymerization step. It is preferable that hydrogen having a high activity such as vinyl position and allyl position of the double bond (olefinic double bond) contained in the diene and/or olefin-derived unit of (4) is extracted. As a result, a radical is generated at the location, and the monomer component forming the polymer chain (B) can be addition-polymerized. At this time, as described above, by adjusting the amount of the olefinic double bond contained in the raw material copolymer (P1), the transparency of the copolymer (P) is increased and the generation of gelation products is suppressed. It will be easier.

In the polymerization step, the raw material copolymer (P1) may be used alone or in combination of two or more. In the latter case, it becomes easy to adjust the transparency, weight average molecular weight, MFR, viscosity and other physical properties of the resin composition.

The monomer component used for forming the polymer chain (B) includes, in addition to the (meth)acrylic-based monomer, a monomer having a polymerizable double bond in the ring structure as a monomer that gives a ring structure unit. It is also possible to use a polymer or the like. For example, when forming the polymer chain (B) having a ring structure in the main chain, a monomer having a polymerizable double bond in the ring structure may be used, and the ring structure forming step may be performed after the polymerization step. You may use the monomer which can form a ring structure by performing. Further, other unsaturated monomers other than the above may be used. For details of these monomer components, the (meth)acrylic monomer forming the polymer chain (B), the monomer providing the ring structure of the polymer chain (B), and the polymer chain (B) are formed. Reference is made to the description of other unsaturated monomers that

The polymerization of the monomer component can be carried out by using a known polymerization method such as a bulk polymerization method, a solution polymerization method, an emulsion polymerization method or a suspension polymerization method, but it is preferable to use the solution polymerization method. When the solution polymerization method is used, it is possible to suppress the mixing of minute foreign matter into the copolymer (P), and it becomes easy to suitably apply the copolymer (P) to optical material applications and the like. As the polymerization method, for example, either a batch polymerization method or a continuous polymerization method can be used. During the polymerization, the monomer components may be charged all at once or added in portions.

The amount of the raw material copolymer (P1) used in the polymerization is preferably 1 part by mass or more, and more preferably 3 parts by mass or more, based on 100 parts by mass of the total amount of the raw material copolymer (P1) and the monomer components. It is preferably 5 parts by mass or more, more preferably 7 parts by mass or more, particularly preferably 9 parts by mass or more, most preferably 12 parts by mass or more, preferably 50 parts by mass or less, and more preferably 40 parts by mass or less. , 35 parts by mass or less is more preferable. The amount of the monomer component used is preferably 50 parts by mass or more, more preferably 60 parts by mass or more, and 65 parts by mass or more with respect to 100 parts by mass in total of the raw material copolymer (P1) and the monomer component. More preferably, also preferably 99 parts by mass or less, more preferably 97 parts by mass or less, further preferably 95 parts by mass or less, even more preferably 93 parts by mass or less, particularly preferably 91 parts by mass or less, most preferably 88 parts by mass or less. preferable.

The polymerization solvent can be appropriately selected according to the composition of the monomer component, and an organic solvent used in a usual radical polymerization reaction can be used. Specifically, aromatic hydrocarbons such as toluene, xylene, and ethylbenzene; aliphatic hydrocarbons such as hexane and cyclohexane; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; tetrahydrofuran, dioxane, ethylene glycol dimethyl ether , Ethers such as diethylene glycol dimethyl ether, anisole; esters such as ethyl acetate, butyl acetate, propylene glycol monomethyl ether acetate, 3-methoxybutyl acetate; cellosolves such as methyl cellosolve, ethyl cellosolve, butyl cellosolve; methanol, ethanol, isopropanol, Examples include alcohols such as n-butanol; nitriles such as acetonitrile, propionitrile, butyronitrile and benzonitrile; chloroform; dimethyl sulfoxide. These solvents may be used alone or in combination of two or more.

The polymerization reaction of the raw material copolymer (P1) and the monomer component is preferably carried out in the presence of a polymerization catalyst (polymerization initiator). Examples of the polymerization catalyst include 2,2′-azobisisobutyronitrile, 2,2′-azobis(2-amidinopropane) dihydrochloride, dimethyl-2,2′-azobis(2-methylpropio). Ate), 4,4′-azobis(4-cyanopentanoic acid), etc.; azo compounds such as potassium persulfate; cumene hydroperoxide, diisopropylbenzene hydroperoxide, di-t-butyl peroxide, lauroyl. Peroxide, benzoyl peroxide, t-butylperoxyisopropyl carbonate, t-amylperoxy-2-ethylhexanoate, t-amylperoxyoctoate, t-amylperoxyisononanoate, t-amylperoxy Organic peroxides such as isopropyl carbonate and t-amyl peroxy 2-ethylhexyl carbonate can be used. These may be used alone or in combination of two or more. Among these, it is preferable to use an organic peroxide having a strong hydrogen abstraction force, and it is particularly preferable to use a peroxycarbonate-based peroxide. The amount of the polymerization catalyst used is preferably 0.01 to 1 part by mass with respect to 100 parts by mass of the monomer component.

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

The polymerization reaction is preferably performed in an atmosphere of an inert gas such as nitrogen gas or under an air stream. In order to reduce the amount of residual monomers, an azo compound and a peroxide may be used together as a polymerization initiator. The reaction temperature is preferably 50°C to 200°C. The reaction time may be appropriately adjusted while observing the degree of progress of the copolymerization reaction and the degree of formation of a gelled product, and for example, 1 hour to 20 hours is preferable.

By the above-mentioned polymerization step, a copolymer (P) in which the polymer chain (B) containing the unit (b1) derived from the (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 the ring structure (for example, maleic anhydride or maleimide) are used as the monomer component, (meth) A copolymer (P) in which a polymer chain (B) having a unit (b1) derived from an acrylic monomer and a ring structural unit (b2) (succinic anhydride structure, succinimide structure) is bonded to the polymer chain (A) is can get.

On the other hand, when a copolymer (P) having a lactone ring structure, a glutaric anhydride structure, or a glutarimide structure is obtained as the ring structural unit (b2) of the polymer chain (B), a ring structure is formed after the polymerization step. It is preferred to perform the steps. In the ring structure forming step, a ring structure is formed in the main chain of the polymer chain (B) having the (meth)acrylic unit formed in the polymerization step. Specifically, the substituents of adjacent (meth)acrylic units of the polymer chain (B) having the (meth)acrylic unit formed in the polymerization step are subjected to a condensation reaction to form a ring on the main chain of the polymer chain (B). Form a structure. The cyclization condensation reaction includes esterification reaction, acid anhydride reaction, amidation reaction, imidization reaction and the like. For example, a glutaric anhydride structure can be formed by acid anhydride conversion of two carboxylic acid groups of adjacent (meth)acrylic units, and a glutarimide structure can be formed by imidization. When one of the adjacent (meth)acrylic units has a protic hydrogen atom-containing group such as a hydroxyl group or an amino group, the protic hydrogen atom-containing group of one (meth)acrylic unit and the other (meth)acrylic unit A lactone ring structure and/or a lactam ring structure can be formed by condensing with a carboxylic acid group of a (meth)acrylic unit.

In the ring structure forming step, the condensation reaction of adjacent (meth)acrylic units is preferably carried out in the presence of a catalyst (cyclization catalyst). As the cyclization catalyst, at least one selected from the group consisting of 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, it is preferable to use an organic phosphorus compound as a catalyst for the cyclization reaction. By using the organic phosphorus compound as the cyclization catalyst, the cyclization condensation reaction can be efficiently performed, and the coloring of the obtained copolymer (P) can be reduced.

Examples of the organic phosphorus compound that can be used as the cyclization catalyst include alkyl(aryl)phosphonous acid and monoesters or diesters thereof; dialkyl(aryl)phosphinic acid and esters thereof; alkyl(aryl)phosphonic acid and these Alkyl(aryl)phosphinous acid and their esters; phosphorous acid monoester, diester or triester; methyl phosphate, ethyl phosphate, 2-ethylhexyl phosphate, octyl phosphate, isodecyl phosphate , Lauryl phosphate, stearyl phosphate, isostearyl phosphate, phenyl phosphate, dimethyl phosphate, diethyl phosphate, di-2-ethylhexyl phosphate, diisodecyl phosphate, dilauryl phosphate, distearyl phosphate, diphosphate Phosphate monoesters, diesters or triesters such as isostearyl, diphenyl phosphate, trimethyl phosphate, triethyl phosphate, triisodecyl phosphate, trilauryl phosphate, tristearyl phosphate, triisostearyl phosphate, triphenyl phosphate; Mono-, di- or tri-alkyl (aryl) phosphines; alkyl (aryl) halogen phosphines; mono-, di- or tri-alkyl (aryl) phosphines; tetraalkyl (aryl) phosphonium halides and the like. These may be used alone or in combination of two or more. Among these, phosphoric acid monoesters or diesters are particularly preferable because they have high catalytic activity and low colorability. The amount of the cyclization catalyst used is preferably, for example, 0.001 to 1 part by mass with respect to 100 parts by mass of the copolymer obtained in the polymerization step.

The reaction temperature in the ring structure forming step is preferably 50°C to 300°C. The reaction time may be appropriately adjusted while observing the degree of progress of the cyclization condensation reaction, and for example, it is preferably carried out for 5 minutes to 6 hours.

The ring structure forming step is preferably performed under heating. At this time, the polymerization solution containing the polymerization solvent obtained in the polymerization step may be heated as it is, or may be heated after devolatilizing the polymerization solvent, or both may be combined. Examples of the reactor used for the cyclocondensation reaction include an autoclave, a kettle type reactor, a device including a heat exchanger and a devolatilizing tank, an extruder with a vent, and the like.

In the ring structure forming step, devolatilization is preferably performed. The devolatilization can be performed by reducing the pressure inside the reactor with a vacuum pump or the like. The devolatilization removes the polymerization solvent used in the polymerization process and brought into the ring structure formation process, alcohol by-produced by the cyclocondensation reaction, etc., and the residual volatile content in the obtained copolymer (P) is reduced. can do. Further, since alcohol and the like produced as a by-product in the cyclocondensation reaction are removed, the reaction equilibrium tends to the production side, which is advantageous. Furthermore, the devolatilization removes low molecular weight compounds, and it is possible to suppress the generation of stains on cast rolls during film molding and silver streaks during injection molding.

When the cyclocondensation reaction is carried out while devolatilizing, it is preferable to carry out the cyclocondensation reaction under reduced pressure from the viewpoint of efficiently devolatilizing. The reduced pressure in the cyclization condensation reaction is, for example, preferably 90 kPa or less in absolute pressure, more preferably 80 kPa or less, and further preferably 70 kPa or less. On the other hand, the absolute pressure at the time of depressurizing is preferably 0.1 kPa or more, and more preferably 1 kPa or more, from the viewpoint that the equipment for realizing the depressurized state does not have excessive specifications and the equipment cost is kept low. When carrying out the cyclization condensation reaction without devolatilization, the cyclization condensation reaction may be carried out under normal pressure or under pressure.

When a vented extruder is used, the extruder preferably has a cylinder, a screw provided in the cylinder, and a heating unit. The cylinder is provided with one or more vents. The vent is preferably provided at least on the downstream side of the raw material charging unit with respect to the transport direction in the extruder, and may be provided on the upstream side of the raw material charging unit.

The cyclization condensation reaction progresses in the process of transferring the copolymer supplied into the extruder from the upstream side to the downstream side of the extruder while kneading with the screw, and the copolymer (P) is discharged from the downstream side of the extruder. Is discharged. A die is preferably provided on the downstream side of the extruder, and by discharging the copolymer (P) from the die, it can be molded into a predetermined shape (film shape or rod shape). For example, pellets can be manufactured by finely cutting a rod-shaped resin.

When the cyclization condensation reaction is carried out in the presence of a cyclization catalyst in the ring structure forming step, it is preferable to add a deactivator after or during the cyclization condensation reaction. For example, when a resin composition containing the copolymer (P) is pelletized or formed into a film, if a cyclization catalyst remains in the resin composition, an alcohol or the like is generated due to a cyclization condensation reaction. Then, undesired foaming may occur. However, such foaming can be prevented by adding a quenching agent after or during the cyclocondensation reaction.

As the deactivator, a substance that can neutralize the cyclization catalyst is preferably used. For example, when the cyclization catalyst is an acidic substance, a basic substance can be used as the quenching agent, and conversely, when the cyclization catalyst is a basic substance, an acidic substance can be used as the quenching agent. .. As explained above, an organic phosphorus compound is preferably used as the cyclization catalyst, and since the compound is often an acidic substance, it is preferable to use a basic substance as the quenching agent. The basic substance is not particularly limited as long as it has a function of stopping the cyclization condensation reaction, and for example, metal carboxylates, metal complexes, metal oxides and the like are used. On the other hand, when a basic substance is used as the cyclization catalyst, the deactivator may be an acidic substance usable for the cyclization catalyst described above.

The timing of adding the quenching agent is preferably during the cyclization condensation reaction or after the reaction and before pelletizing or film-forming the resin composition containing the copolymer (P). For example, a deactivator may be added to the molten resin composition, or a deactivator may be added to the resin composition dissolved in a solvent. When the cyclization condensation reaction is performed using the extruder as described above, the deactivator may be added at a position after the cyclization condensation reaction is sufficiently performed in the extruder.

The conversion rate of the (meth)acrylic monomer is preferably 85% or more, more preferably the conversion rate of various monomers in the polymerization reaction is 85% or more, and all are 88% or more. Is more preferable, and it is particularly preferable that both are 90% or more. When the conversion rate of (meth)acrylic monomers and other various monomers is lower than 85%, a separate facility for collecting the monomers is newly required, or residual monomers are not desired in the next step or the like. There is a possibility that productivity will be significantly impaired by causing a reaction and generating foreign matter.

The weight average molecular weight of the copolymer (P) is preferably 20,000 or more, more preferably 5,000 or more, even more preferably 30,000 or more, and preferably 600,000 or less, more preferably 400,000 or less, It is more preferably 300,000 or less. By setting the weight average molecular weight of the copolymer (P) in such a range, the moldability of the resin composition containing the copolymer (P) is improved.

The weight average molecular weight of the copolymer (P) is preferably 1.1 times or more, more preferably 1.2 times or more, further preferably 1.3 times or more, and 10 times the weight average molecular weight of the polymer chain (A). It is preferably not more than twice, more preferably not more than 7 times, further preferably not more than 5 times. As a result, it becomes easy to impart each property of transparency and mechanical strength to the resin composition in good balance.

The refractive index of the copolymer (P) is preferably close to the refractive index of the polymer chain (A), which facilitates ensuring the transparency of the resin composition. 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 0.02 or less. More preferable. From the same viewpoint, it is preferable that the refractive index of the polymer chain (A) and the refractive index of the polymer chain (B) in the copolymer (P) are close to each other. The difference between the refractive index and the refractive index of the polymer chain (B) is preferably less than 0.1, more preferably 0.05 or less, still more preferably 0.02 or less.

The resin composition may contain only one type of copolymer (P), or may contain two or more types. In addition to the copolymer (P) described above, it may contain another polymer. In this case, the resin composition may contain the copolymer (P) as a resin component (matrix resin), or may contain another polymer as a resin component (matrix resin). As the other polymer, the (meth)acrylic polymer (Q) is preferably used because it has excellent compatibility with the copolymer (P). This makes it easy to increase the transparency and heat resistance of the resin composition.

The (meth)acrylic polymer (Q) may be any polymer having a unit derived from a (meth)acrylic monomer, and is preferably the (meth)acrylic ester described in the above polymer chain (B). It has a unit of origin. The (meth)acrylic polymer (Q) may have units derived from other unsaturated monomers described in the polymer chain (B) above. The (meth)acrylic polymer (Q) is included in the polymer chain (B) of the copolymer (P) from the viewpoint of increasing the compatibility with the copolymer (P) in the resin composition (meta). ) It is more preferable to have a unit (b1) derived from an acrylic monomer.

The (meth)acrylic polymer (Q) preferably has a ring structure, and more preferably has a ring structure in its main chain. This can enhance the heat resistance of the resin composition and the film obtained therefrom. The ring structure of the main chain of the (meth)acrylic polymer (Q) includes a lactone ring structure, a cyclic imide structure (for example, a succinimide structure, a glutarimide structure, etc.), a cyclic anhydride structure (for example, a succinic anhydride structure, (Glutaric anhydride structure, etc.) and the like are preferable, and for the details of these ring structures, the description regarding the ring structure of the polymer chain (B) is referred to. Among them, the (meth)acrylic polymer (Q) preferably has the same ring structure as the ring structure of the polymer chain (B) of the copolymer (P) in the main chain.

The (meth)acrylic polymer (Q) preferably has a unit derived from the (meth)acrylic monomer and a unit having a ring structure in the main chain, and the polymer chain (B) of the copolymer (P) It is more preferable to have the same (meth)acryl unit as the (meth)acryl unit contained in and also have the same ring structure unit as the ring structure unit included in the polymer chain (B). This increases the compatibility between the (meth)acrylic polymer (Q) and the copolymer (P), and facilitates the transparency and heat resistance of the resin composition and the film obtained therefrom. From the viewpoint of further improving the heat resistance of the resin composition, the (meth)acrylic polymer (Q) preferably has a ring structure unit containing a cyclic imide structure.

When such a (meth)acrylic polymer (Q) is polymerized to form the copolymer (P), it is easy to polymerize the (meth)acrylic polymer (Q) together. In the method for producing the copolymer (P) described above, the (meth)acrylic polymer (Q) corresponding to the polymer chain (B) of the copolymer (P) is also simultaneously produced together with the copolymer (P). A resin containing the copolymer (P) and the (meth)acrylic polymer (Q), which is produced, but does not separate the copolymer (P) and the (meth)acrylic polymer (Q). A composition can be obtained.

The method for producing the resin composition is not limited to the above method, and the copolymer (P) may be isolated and mixed with another polymer to give a resin composition. Further, in the above-mentioned method for producing the copolymer (P), even after the completion of the graft polymerization reaction to the copolymer (P1), another monomer is further added to carry out the polymerization reaction to obtain a resin composition. Good. Alternatively, with respect to the mixture of the copolymer (P) and the (meth)acrylic polymer (Q) obtained by the method for producing the copolymer (P), another polymer (for example, another polymer A (meth)acrylic polymer may be added to obtain a resin composition. When another polymer is added and mixed, it may be melt-kneaded, and in this case, a general device such as a kneader or a multi-screw extruder can be used.

As explained above, the resin composition may contain a polymer other than the (meth)acrylic polymer (Q), and examples of such a polymer include polyethylene, polypropylene, and ethylene-propylene. Polymers, olefin polymers such as poly(4-methyl-1-pentene); halogen-containing polymers such as vinyl chloride and chlorinated vinyl resins; polystyrene, styrene-methyl methacrylate copolymer, styrene-acrylonitrile copolymer Polymers, styrene polymers such as acrylonitrile-butadiene-styrene copolymers; polyesters such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate; polyamides such as nylon 6, nylon 66, nylon 610; polyacetals; polycarbonates; polyphenylene oxide Polyphenylene sulfide; Polyetheretherketone; Polysulfone; Polyethersulfone; Polyoxypentylene; Polyamideimide; Cycloolefin polymer; Cellulose derivative; Polybutadiene rubber, ABS resin or ASA resin containing (meth)acrylic rubber Rubbery polymer;

In the method for producing the resin composition, the polymerization step or the ring structure forming step described above may be followed by a filtration step. By performing the filtration step, the amount of foreign matter in the resin composition can be reduced, and the resin composition can be suitably applied to applications such as optical films that require high quality. In addition, when a film is formed from the resin composition, it is easy to obtain a highly transparent film with few surface irregularities and defects. The filtration step can be continuously performed subsequent to the above-described polymerization step or ring structure formation step.

As a filter used for filtration, a conventionally known filter can be used, and although not particularly limited, for example, a leaf disc filter, a candle filter, a pack disc filter, a cylindrical filter, or the like can be used. Above all, it is preferable to use a leaf disk filter or a candle filter having a large effective filtration area.

The filtration accuracy (pore diameter) of the filter is usually, for example, 15 μm or less. When the resin composition 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 filtration accuracy is not particularly limited and is, for example, 0.2 μm or more.

The content ratio of the copolymer (P) in the resin composition is not particularly limited, but the content ratio of the copolymer (P) is preferably 1% by mass or more in 100% by mass of the solid content of the resin composition. Mass% or more is more preferable, 5 mass% or more is still more preferable, and 15 mass% or more is still more preferable. This makes it easier to increase the mechanical strength of the film and increase the fluidity when the resin composition is heated and melted. The upper limit of the content ratio of the copolymer (P) in the resin composition is not particularly limited, and the resin composition may be composed of only the copolymer (P). The content ratio of P) may be 90 mass% or less, 70 mass% or less, 50 mass% or less, 40 mass% or less, or 30 mass% or less. When the resin composition contains a solvent, the solid content of the resin composition means the amount of the resin composition excluding the solvent.

The content ratio of the polymer chain (A) of the copolymer (P) in 100% by mass of the solid content of the resin composition is preferably 1% by mass or more, more preferably 3% by mass or more, further preferably 5% by mass or more. , 12 mass% or more, more preferably 50 mass% or less, more preferably 40 mass% or less, still more preferably 30 mass% or less. When the content of the polymer chain (A) in the resin composition is 1% by mass or more, it becomes easy to increase the mechanical strength of the film and the fluidity when the resin composition is heated and melted.

The content ratio of the ring structure unit in the resin composition is not particularly limited, but the content ratio of the ring structure unit in 100% by mass of the solid content of the resin composition is preferably 3% by mass or more, and more preferably 5% by mass or more. , 7% by mass or more, 60% by mass or less, 40% by mass or less, 30% by mass or less, and 20% by mass or less are more preferable. By adjusting the content ratio of the ring structural unit in this manner, it becomes easy to enhance both heat resistance and mechanical strength in a well-balanced manner. In addition, the content ratio of the ring structural unit explained here is based on the ring structural unit contained in the main chain of the polymer chain (B) of the copolymer (P) and the main chain of the (meth)acrylic polymer (Q). It means the total content of the contained ring structural units, for example, the content of the structures represented by the above formulas (1) to (3).

When the resin composition contains the (meth)acrylic polymer (Q), the content of the (meth)acrylic polymer (Q) is 1% by mass or more in 100% by mass of the solid content of the resin composition. Preferably, 10% by mass or more is more preferable, 20% by mass or more is more preferable, 30% by mass or more is still more preferable, 99% by mass or less is preferable, 95% by mass or less is more preferable, and 90% by mass or less is further preferable. , 85 mass% or less is even more preferable.

The total content of the polymer chain (B) of the copolymer (P) and the (meth)acrylic polymer (Q) in 100% by mass of the solid content of the resin composition is preferably 50% by mass or more, and 60% by mass. The above is more preferable, 70% by mass or more is further preferable, 97% by mass or less is preferable, 95% by mass or less is more preferable, and 88% by mass or less is further preferable. This makes it easier to adjust the transparency and mechanical strength when the film or sheet is molded.

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

The resin composition may contain various additives as long as the effects of the present invention are not impaired. Examples of the additives include ultraviolet absorbers; phenol-based, phosphorus-based, sulfur-based, etc. antioxidants; light stabilizers, weather stabilizers, heat stabilizers, and other stabilizers; glass fiber, carbon fiber, and other reinforcing materials. Near-infrared absorbers; flame retardants such as tris(dibromopropyl)phosphate, triallyl phosphate, antimony oxide; phase difference adjusters such as phase difference increasing agents, phase difference reducing agents, phase difference stabilizers; anionic and cationic systems , An antistatic agent containing a nonionic surfactant; a coloring agent such as an inorganic pigment, an organic pigment or a dye; an organic filler or an inorganic filler; a resin modifier; an organic filler or an inorganic filler; The content ratio of each additive in 100% by mass of the solid content of the resin composition is preferably in the range of 0 to 5% by mass, more preferably 0 to 2% by mass.

4. In-plane retardation Re, thickness direction retardation Rth, and stress optical coefficient Cr In the following, the in-plane retardation Re, thickness direction retardation Rth, and stress optical coefficient Cr will be described.

<In-plane retardation Re, thickness direction retardation Rth>
The in-plane retardation Re of the film and the retardation Rth in the thickness direction can be obtained from the following formulas. The refractive index in the slow axis direction in the plane of the film is nx, the refractive index in the fast axis direction in the plane of the film is ny, the refractive index in the thickness direction of the film is nz, and the thickness of the film is d. To do.
In-plane retardation Re=(nx−ny)×d
Thickness direction retardation Rth=[(nx+ny)/2−nz]×d

A stretched film obtained by subjecting an unstretched film obtained from the resin composition to free-end uniaxial stretching at a draw ratio of 2 at a temperature 4° C. higher than the glass transition temperature of the resin composition of the present invention, having a wavelength of 589 nm. The in-plane retardation Re per thickness of 40 μm with respect to light is preferably 30 nm or more, more preferably 40 nm or more, and further preferably 50 nm or more. The in-plane retardation Re is preferably 400 nm or less, more preferably 350 nm or less. When the in-plane retardation Re is in the above range, a sufficient retardation required for various retardation films such as λ/2 plate and λ/4 plate can be exhibited.

In order to exhibit the basic properties as a retardation film, it is necessary that the film obtained from the resin composition has a predetermined in-plane retardation Re. However, in the case of having a predetermined in-plane retardation, not only the magnitude (absolute value) of the in-plane retardation Re but also the magnitude (absolute value) of the thickness direction retardation Rth becomes large, and the contrast is likely to decrease. Wherein, a polymer chain (A) having a unit derived from a diene and/or an olefin, a polymer chain having a unit (b1) derived from a (meth)acrylic monomer and a unit (b2) having a ring structure in its main chain When a film is produced by using the resin composition of the present invention containing (B), the magnitude (absolute value) of the thickness direction retardation Rth can be suppressed to a small value, the reduction in contrast can be suppressed, and the viewing angle compensability can be improved. Can be higher.

The polymer chain (A) having a unit derived from a diene and/or an olefin contained in the resin composition of the present invention is soft and difficult to be oriented even when subjected to stretching and the like, while the resin composition of the present invention Since the polymer chain (B) contained in the polymer is present in a phase-separated state, it exhibits positive form birefringence. Form birefringence is the birefringence exhibited by a material that has structures that are much larger than molecules and smaller than the wavelength of light in a periodic or collective manner. The directionality and strength of the birefringence of is determined, and it is always a positive value.
On the other hand, the polymer chain (B) having a unit derived from the (meth)acrylic monomer of the present invention exhibits a negative orientation birefringence. Orientation birefringence is generally birefringence that occurs when the main chain of a chain polymer (polymer chain) is oriented.
As described above, the positive form birefringence is determined by the size and shape of the polymer chain (A), and the negative orientation birefringence is determined by the orientation of the polymer chain (B), and is produced using the resin composition of the present invention. In the film, it is possible to control these positive/negative birefringence.

A stretched film obtained by subjecting an unstretched film obtained from the resin composition to free-end uniaxial stretching at a draw ratio of 2 at a temperature 4° C. higher than the glass transition temperature of the resin composition of the present invention, having a wavelength of 589 nm. The thickness direction retardation Rth per thickness of 40 μm with respect to light is a negative value (the stretched film is a negative retardation film), and the absolute value of the thickness direction retardation Rth is 200 nm or less. The thickness is preferably 170 nm or less, more preferably 140 nm or less, particularly preferably 100 nm or less. The thickness direction retardation Rth caused by the polymer chain (A) is a positive value, and the thickness direction retardation Rth caused by the polymer chain (B) is a negative value, but caused by the polymer chain (B). The absolute value of the thickness direction retardation Rth can be made larger than the thickness direction retardation Rth caused by the polymer chain (A), and the thickness direction retardation Rth caused by the polymer chain (A) can be It can be completely canceled and can be a negative retardation film. When the thickness direction retardation Rth is in the above range, excellent viewing angle compensation can be exhibited.

<Stress optical coefficient Cr>
In the resin composition, the stress optical coefficient Cr is −25.0×10 ⁻¹¹ Pa ⁻¹ or more and −4.0×10 ⁻¹¹ Pa ⁻¹ or less, and −20.0×10 ⁻¹¹ Pa ⁻¹ or more. It is preferably −6.0×10 ⁻¹¹ Pa ⁻¹ or less, more preferably −15.0×10 ⁻¹¹ Pa ⁻¹ or more and −7.0×10 ⁻¹¹ Pa ⁻¹ or less, and − It is more preferably 12.0×10 ^-11 Pa ^-1 or more and -8.0×10 ^-11 Pa ^-1 or less. Since the stress optical coefficient Cr is measured at a temperature not lower than Tg of the resin composition, it serves as an index of how much retardation appears in the film by stretching the unstretched film. Specifically, the stress optical coefficient Cr means an unstretched film obtained by molding a resin composition and stretched at a temperature of Tg or higher to give a retardation film. At that time, the unstretched film is stretched. It is the slope of the change in the retardation of the retardation film obtained with respect to the stress σ when the stress σ applied to is changed. The stretched film is molded to measure the stress optical coefficient Cr. The stress optical coefficient Cr is a value specific to the resin composition, and the stress optical coefficient Cr of the resin composition of the present invention depends on the polymer chain (B). It is a value. When the stress optical coefficient Cr of the resin composition has a negative value, the retardation due to the polymer chain (B) has a negative value, and a negative retardation film can be obtained. When the stress optical coefficient Cr is in the above range, sufficient retardation required for various retardation films such as λ/2 plate and λ/4 plate can be exhibited. The value of the stress optical coefficient Cr does not depend on the stretching ratio of the film, stretching conditions, and the like. The stress optical coefficient Cr of the resin composition is obtained by the method described in Examples.

5. Physical Properties of Resin Composition Physical properties of the resin composition other than the stress optical coefficient Cr are as follows.

<Glass transition temperature>
The resin composition of the present invention preferably has a glass transition temperature of 110° C. or higher. As a result, the heat resistance of the resin composition can be increased, and the resin composition can be applied to applications requiring heat resistance, such as image display devices. The resin composition preferably has a glass transition temperature in the temperature range of 120° C. or higher. The upper limit of the glass transition temperature is preferably less than 300° C., more preferably less than 200° C., and even more preferably less than 180° C. from the viewpoint of ensuring moldability into a film or the like.

The resin composition preferably has a glass transition temperature of 110° C. or higher and lower than 110° C., respectively. A glass transition temperature of 110° C. or higher is referred to as a “high temperature side glass transition temperature”, and a glass transition temperature of less than 110° C. is referred to as a “low temperature side glass transition temperature”. The resin composition may have a plurality of glass transition temperatures on the high temperature side, or may have a plurality of glass transition temperatures on the low temperature side. When the resin composition has a glass transition temperature on the high temperature side, the heat resistance of the resin composition is enhanced. Since the resin composition has a glass transition temperature on the low temperature side, the mechanical strength and impact resistance of the resin composition can be increased. The preferable range of the glass transition temperature on the high temperature side of the resin composition is as described above. The glass transition temperature on the low temperature side of the resin composition is preferably lower than 50° C., more preferably lower than 30° C., further preferably lower than 10° C., preferably −100° C. or higher, more preferably −90° C. or higher, −80. C. or higher is more preferable.

<Weight average molecular weight>
The weight average molecular weight of the resin composition is preferably 20,000 or more, more preferably 5,000 or more, even more preferably 30,000 or more, even more preferably 50,000 or more, particularly preferably 100,000 or more, and 60 It is preferably 10,000 or less, more preferably 400,000 or less, still more preferably 300,000 or less. By setting the weight average molecular weight of the resin composition in such a range, the moldability of the resin composition is improved. The weight average molecular weight of the resin composition means a value in terms of polystyrene measured by gel permeation chromatography of the resin composition, and the resin composition is a copolymer (P) and a (meth)acrylic polymer (Q). In the case of containing, the weight average molecular weight of the resin composition is the entire weight average molecular weight of these plural kinds of polymers.

<Number average molecular weight>
The number average molecular weight of the resin composition is preferably 20,000 or more, more preferably 5,000 or more, even more preferably 10,000 or more, particularly preferably 30,000 or more, most preferably 40,000 or more, and 400,000 or less. It is preferably 300,000 or less, more preferably 200,000 or less, most preferably 100,000 or less. By setting the number average molecular weight of the resin composition in such a range, the moldability of the resin composition is improved. The number average molecular weight of the resin composition means a value in terms of polystyrene measured by gel permeation chromatography of the resin composition, and the resin composition contains the copolymer (P) and the (meth)acrylic polymer (Q). In that case, the number average molecular weight of the resin composition is the total number average molecular weight of these plural kinds of polymers.

<Melt flow rate (MFR)>
The resin composition of the present invention preferably has a melt flow rate of 10 g/10 min or more, measured at a temperature of 240° C. and a load of 10 kgf (98 N) according to JIS K 7210 B method, and 11 g/10 min or more. Is more preferable, and 12 g/10 minutes or more is further preferable. When the resin composition has such a melt flow rate, the melt viscosity when the resin composition is heated and melted is lowered, and the moldability can be improved. Further, when removing the foreign matter from the melt of the resin composition through the filter prior to the molding process, the pressure loss of the filter can be suppressed to be low, and the productivity can be improved. On the other hand, even if the melt viscosity is too low, the molding process such as film molding and stretching may be difficult, or the resin substituting property may be deteriorated when the molding process of another resin is performed by the same machine. The melt flow rate is preferably 40 g/10 minutes or less, more preferably 35 g/10 minutes or less, still more preferably 30 g/10 minutes or less.

<Insoluble matter in chloroform>
The resin composition preferably has an insoluble content in chloroform of 10% by mass or less, more preferably 8% by mass or less, still more preferably 5% by mass or less. In this case, the resin composition has a small amount of foreign matter contained therein, and when a film is formed from the resin composition, there are few surface irregularities and defects, and a highly transparent film can be easily obtained. Further, when removing the foreign matter from the resin composition, the load on the foreign matter removing filter is reduced, and the manufacturing efficiency is improved. The insoluble matter in chloroform of the resin composition was obtained by adding 1 g of the resin composition to 20 g of chloroform, filtering this with a Teflon (registered trademark) membrane filter having a pore size of 0.5 μm, and collecting the insoluble matter in the membrane filter. Can be determined by measuring.

6. Physical Properties of Film Formed from Resin Composition of the Present Invention Physical properties of film formed from the resin composition of the present invention are as follows.

The film formed from the resin composition of the present invention preferably has an in-plane retardation Re of 30 nm or more per 40 μm in thickness for light having a wavelength of 589 nm, more preferably 40 nm or more, and more preferably 50 nm or more. Is more preferable. The in-plane retardation Re is preferably 400 nm or less, more preferably 350 nm or less. When the in-plane retardation Re is in the above range, a sufficient retardation required for various retardation films such as λ/2 plate and λ/4 plate can be exhibited.

In the film formed from the resin composition of the present invention, the thickness direction retardation Rth per thickness 40 μm for the light of wavelength 589 nm is a negative value, and the absolute value of the thickness direction retardation Rth is 200 nm or less. Is preferably 170 nm or less, more preferably 140 nm or less, particularly preferably 100 nm or less. The thickness direction retardation Rth caused by the polymer chain (A) is a positive value, and the thickness direction retardation Rth caused by the polymer chain (B) is a negative value, but caused by the polymer chain (B). The absolute value of the thickness direction retardation Rth can be made larger than the thickness direction retardation Rth caused by the polymer chain (A), and the thickness direction retardation Rth caused by the polymer chain (A) can be It can be completely canceled and can be a negative retardation film. When the thickness direction retardation Rth is in the above range, excellent viewing angle compensation can be exhibited.

<Mechanical strength>
The film formed from the resin composition of the present invention preferably has a smaller folding endurance of 5 times or more among the folding endurances in the MIT test based on JIS P 8115 in the film longitudinal direction and the width direction. It is more preferably at least 100 times, even more preferably at least 100 times, particularly preferably at least 200 times, and most preferably at least 500 times.
The film formed from the resin composition of the present invention preferably has a folding endurance of 250 times or more, which is the larger of the folding endurances according to the MIT test based on JIS P 8115 in the film longitudinal direction and the width direction. It is more preferably at least 1000 times, even more preferably at least 1000 times, particularly preferably at least 5000 times, and most preferably at least 10,000 times.

<Thickness>
The film formed from the resin composition of the present invention preferably has a thickness of 5 μm or more, more preferably 15 μm or more, from the viewpoint of enhancing the strength. On the other hand, from the viewpoint of reducing the thickness of the film, the thickness is preferably 350 μm or less, more preferably 200 μm or less, still more preferably 150 μm or less. The thickness of the film can be measured using, for example, a Digimatic Micrometer manufactured by Mitutoyo Corporation.

<Internal haze>
The film formed from the resin composition of the present invention has an internal haze per thickness of 100 μm of preferably 5.0% or less, more preferably 3.0% or less, and 2.0% or less. More preferably, 1.0% or less is particularly preferable.

7. Film Forming Method The resin composition of the present invention can be formed into a film by molding according to a known method. For example, a solution casting method (solution casting method), a melt extrusion method, a calendering method, a compression molding method, or the like is used to form a film. It can be molded. Among these, the solution casting method and the melt extrusion method are preferable. At that time, it may be directly fed to an extruder or the like to form a film without being pelletized after the polymerization.

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

Examples of the melt extrusion method include a T-die method and an inflation method. When the film is formed by the melt extrusion method, it may be stretched to obtain a stretched film. By stretching, the mechanical strength of the film can be further improved. As a stretching method for obtaining a stretched film, a conventionally known stretching method can be applied. Examples include uniaxial stretching such as free width uniaxial stretching and constant width uniaxial stretching; sequential biaxial stretching, biaxial stretching such as simultaneous biaxial stretching, and the like. In order to obtain a retardation film excellent in viewing angle compensation. Is preferably uniaxially stretched (a uniaxially stretched film), and more preferably free-end uniaxially stretched. When the unstretched film is uniaxially stretched in the x-axis direction, it is possible to obtain a retardation film exhibiting a desired retardation and excellent in viewing angle compensation. 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 retardation value, and are not particularly limited.

Examples of the stretching device include a roll stretching machine, a tenter type stretching machine, and a small-scale experimental stretching device such as a tensile tester and a uniaxial stretching machine. Any of these devices can be used.

When the stretched film is applied to the optical film, heat treatment (annealing) may be performed after stretching, if necessary, in order to stabilize the optical properties and mechanical properties of the optical film.

8. Optical Film Since the resin composition of the present invention is excellent in transparency, the film made of the resin composition of the present invention can be suitably used as an optical film. The use of the optical film is not particularly limited, but for example, it can be used for optical compensation (color tone compensation, viewing angle compensation) of LCDs of various modes including VA mode and IPS mode liquid crystal display devices (LCD). In addition to the LCD, it can be suitably used for various image display devices and optical devices.

The above optical film can also be used as a polarizer protective film by laminating it on one side or both sides of a polarizer. It can also be used as a transparent conductive film by forming a transparent conductive layer on the surface.

The optical film (for example, a retardation film, a polarizer protective film, a transparent conductive film, a film for light conversion) can be suitably used for an image display device. Examples of the image display device include a liquid crystal display device and the like. For example, in the case of a liquid crystal display device, the image display unit may be configured to have the optical film of the present invention together with members such as a liquid crystal cell, a polarizing plate and a backlight. Examples of the image display device other than the liquid crystal display device include an electroluminescence (EL) display panel, a plasma display panel (PDP), a field emission display (FED), a QLED, and a micro LED.

Hereinafter, the present invention will be described more specifically with reference to Examples, but the present invention is not limited to the following Examples, and may be appropriately modified within a range compatible with the gist of the preceding and the following. Of course, it is possible to carry out, and all of them are included in the technical scope of the present invention. In the following description, "part" means "part by mass" and "%" means "% by mass" unless otherwise specified.

(1) Weight average molecular weight (Mw) and number average molecular weight (Mn)
The weight average molecular weight and number average molecular weight of the resin composition were determined by polystyrene conversion using gel permeation chromatography (GPC). The apparatus and measurement conditions used for the measurement are as follows.
-Measuring system: Tosoh Corp., GPC system HLC-8220
-Measurement side column configuration Guard column: Tosoh Corp., TSKguardcolumn SuperHZ-L
Separation column: Tosoh Corp., TSKgel SuperHZM-M Two serial connection-reference side column configuration Reference column: Tosoh Corp., TSKgel SuperH-RC
-Developing solvent: Chloroform (Wako Pure Chemical Industries, Ltd., special grade)
-Solvent flow rate: 0.6 mL/min-Standard sample: TSK standard polystyrene (Tosoh Corporation, PS-oligomer kit)

(2) Glass transition temperature (Tg)
The glass transition temperature of the resin composition was determined according to JIS K 7121 (2012). Specifically, it was obtained by using a differential scanning calorimeter (manufactured by Rigaku, Thermo plus EVO DSC-8230) and raising the temperature of the sample from room temperature to 200° C. (heating rate 20° C./min) under a nitrogen gas atmosphere. The obtained DSC curve was evaluated by the starting point method. Α-alumina was used as a reference. For the glass transition temperature of less than 40°C, the sample was heated from -100°C to 60°C (temperature rising rate 10°C/min) in a nitrogen gas atmosphere using a differential scanning calorimeter (DSC-3500 manufactured by Netti). The obtained DSC curve was evaluated by the starting point method. An empty container was used as a reference.

(3) Monomer conversion rate The monomer conversion rate (reaction rate) was determined by measuring the amount of residual monomer in the polymerization reaction liquid using gas chromatography (Shimadzu Corporation, GC-2014).

(4) Stress optical coefficient Cr
The stress optical coefficient Cr of the resin composition was determined as follows with the measurement wavelength set to 589 nm.

First, the resin composition obtained in the example was hot press molded by a hot press at 250° C. to obtain an unstretched film (thickness 160 μm) of the polymer. Next, the produced unstretched film was cut out in a size of 20 mm×60 mm to obtain a Cr evaluation test piece. Next, on one short side of the test piece, a weight having a weight of 1 N/mm ² or less applied to the test piece during stretching was selected and attached, and then the Tg of the polymer to be evaluated was +20°C. The sample was stored in the held constant temperature dryer (DOV-450A manufactured by As One) and left for 1 hour. When storing the test piece in the constant temperature dryer, fix the other short side of the test piece with a chuck, and the stress applied to the test piece by the weight causes the test piece to move in the long side direction (vertical direction) of the free end uniaxially. It was made to be stretched. In addition, the distance between the chuck and the weight in the test piece was set to 40 mm when it was stored. After heating and stretching for 1 hour, the heater of the dryer was turned off and the test piece was naturally cooled in the dryer as it was. At the time when the temperature in the oven reached Tg-40°C of the polymer, the test piece (uniaxially stretched film) was taken out, and the thickness of the taken out test piece and the in-plane retardation Re for light having a wavelength of 589 nm were measured, The in-plane birefringence Δn of the test piece was calculated. Separately from this, the cross-sectional area of the test piece after being stretched by the load of the weight was obtained, and the stress σ(Pa) applied to the film was calculated from the cross-sectional area and the load of the weight. Δn and σ were calculated for each load while changing the weight of the weight, and the slope of Δn with respect to the obtained σ was calculated by the least square method, and this was defined as the stress optical coefficient Cr(Pa ⁻¹ ). When the orientation angle when measuring the in-plane retardation Re is near 0° with respect to the stretching direction (load application direction), the stress optical coefficient Cr has a positive sign. In this case, the orientation birefringence of the polymer to be evaluated is positive. On the other hand, when the orientation angle is close to 90° with respect to the stretching direction, the stress optical coefficient Cr has a negative sign. In this case, the orientation birefringence of the polymer to be evaluated is negative. The larger the absolute value of Cr, the higher the birefringence development property (phase difference development property) due to stretching.

(5) Melt flow rate (MFR)
The melt flow rate was measured using a melt indexer (manufactured by Takara Industry Co., Ltd.) at a temperature of 240° C. and a load of 98 N (10 kgf) according to JIS K 7210 (method B).

(6) Foreign matter evaluation (filtration test)
The gelation of the resin composition was evaluated by a filter filtration test. For the evaluation of foreign matter, the resin composition obtained in the example was dissolved in chloroform to prepare a 0.1% by mass chloroform solution, and this was applied to a filter (GL Science Co., Chromatodisc 13N, pore diameter 0.45 μm) at the tip. ) Was used for filtration using a plastic syringe. If 2 mL of the chloroform solution of the resin composition was completely filtered, it was evaluated as ◯, and if the solution could not be filtered by 2 mL, it was evaluated as ×.

(7) Film Thickness The film thickness was measured using a Digimatic Micrometer (Mitutoyo).

(8) Phase difference in terms of thickness of 40 μm The in-plane retardation Re and the thickness direction retardation Rth of the stretched film produced in the example with respect to light having a wavelength of 589 nm were measured by a fully automatic birefringence meter (“KOBRA manufactured by Oji Scientific Instruments”). -WR") was used under the conditions of an incident angle of 40°. Specifically, the refractive index in the slow axis direction in the plane of the film is nx, the refractive index in the fast axis direction in the plane of the film is ny, the refractive index in the thickness direction of the film is nz, and the thickness of the film is Where d is the in-plane retardation Re and the thickness direction retardation Rth, respectively. In the following examples, the in-plane retardation Re and the thickness direction retardation Rth were determined with the film thickness d set to 40 μm.
In-plane retardation Re=(nx−ny)×d
Thickness direction retardation Rth=[(nx+ny)/2−nz]×d

(9) Internal haze in terms of thickness of 100 μm A quartz cell was filled with 1,2,3,4-tetrahydronaphthalene (tetralin), and the unstretched film produced in the example was immersed in the haze meter (Nippon Denshoku Color Co., Ltd.). Haze was measured using an industrial company, NDH-5000), and the internal haze per 100 μm thickness was calculated according to the following formula: Internal haze per 100 μm thickness (%)=obtained measured value (%)× (100 μm/film thickness (μm)). In addition, the measurement was performed using three films, and the internal haze in terms of a thickness of 100 μm was calculated from the average value.

(10) Number of folding endurance by MIT test (MIT strength)
The stretched film produced in the example was cut into a size of 90 mm×15 mm to give a test piece, and a MIT folding endurance tester (BE-201, manufactured by Tester Sangyo Co., Ltd.) was used to obtain a temperature of 23° C. and a relative humidity of 50%. A load of 200 gf was applied in the atmosphere, and the number of times of MIT folding endurance test was measured according to JIS P 8115 (2001). For the measurement, the folding endurance when folded in the film stretching direction was measured using five samples, and the average value of 3 points excluding the maximum value and the minimum value was taken as the folding endurance when folded in the film stretching direction. .. Further, the number of folding endurances when folded in the direction orthogonal to the film stretching direction (unstretched direction) was calculated in the same manner as the number of folding endurances when folded in the film stretching direction.

<Example 1>
A reactor equipped with a stirrer, a temperature sensor, a cooling pipe, and a nitrogen introducing pipe was used as a SEBS triblock copolymer, and Asahi Kasei's Tuftec (registered trademark) P1083 (olefin double bond amount 2.01 mmol/g, styrene unit). Content 18.3 mass%, refractive index 1.500, weight average molecular weight 94,000, number average molecular weight 64,000) 2.5 parts, Asahi Kasei Corporation Tuftec (registered trademark) H1517 (olefinic double bond Amount 0.10 mmol/g, styrene unit content 39% by mass, refractive index 1.523, weight average molecular weight 99,000, number average molecular weight 75,000) 12.5 parts, methyl methacrylate (MMA) 53. 6 parts, 0.03 part of n-dodecyl mercaptan (nDM), and 100 parts of toluene as a polymerization solvent were charged, and the temperature was raised to 105° C. while passing nitrogen through them. After that, 0.05 part of t-butylperoxyisopropyl carbonate (Kayakaku (registered trademark) Bic75 manufactured by Kayaku Akzo Co., Ltd.) was added as an initiator, and 21.2 parts of styrene (St) and 1 part of toluene were diluted to 0. 0.15 parts of N-cyclohexylmaleimide (CMI) dissolved in 10 parts of toluene with 15 parts of t-butylperoxyisopropyl carbonate over 3 hours was added dropwise over 5 hours at a constant rate of 105-110. Solution polymerization was carried out at 0°C, and aging was carried out for 2 hours after the completion of both droppings. This includes an acrylic copolymer polymerized and formed from MMA, CMI, and St, and a graft copolymer in which the copolymer chain is bonded to a diene/olefin-derived unit of the SEBS triblock copolymer chain. A resin composition was obtained. The conversion rate of MMA calculated from the amount of residual monomers in the polymerization reaction solution was 92.1%, the conversion rate of CMI was 99.2%, and the conversion rate of St was 96.9%. The composition ratio (mass basis) of the acrylic copolymer chain bonded to the SEBS triblock copolymer chain and the acrylic copolymer calculated from the conversion rate was MMA:CMI:St=61.7:12. The ratio of the ring structure unit in the resin composition was 10.7% by mass.
Next, the obtained polymerization reaction liquid was converted into a resin of 600 g/h in a vent type screw twin-screw extruder (hole diameter: 15 mm, L/D: 45) having one rear vent and two for vents. The pellets of the transparent resin composition were obtained by introducing at a processing speed, devolatilizing in this extruder, and extruding. The operating conditions of the twin-screw extruder were a barrel temperature of 260°C, a rotation speed of 300 rpm, and a degree of vacuum of 13.3 to 400 hPa (10 to 300 mmHg). The weight average molecular weight of the obtained resin composition was 147,000, the number average molecular weight was 66,000, the glass transition temperature on the high temperature side was 122°C, the glass transition temperature on the low temperature side was -62°C, and the MFR was 22 g/ After 10 minutes, the refractive index was 1.520, the styrene unit content in the resin composition was 27.1% by mass, and the stress optical coefficient Cr was −8.5×10 ⁻¹¹ Pa ⁻¹ . Then, when the obtained resin composition was evaluated for gelation, it was possible to suitably perform filtration.

<Examples 2 to 5, Comparative Examples 1 and 2>
SEBS triblock copolymer, methyl methacrylate (MMA), N-cyclohexylmaleimide (CMI), styrene (St) except that the content described in Table 1, the same as in Example 1, A resin composition was prepared. Note that in Example 4, N-phenylmaleimide (PMI) was used instead of CMI.

As described in Table 1, in Example 2, Kraton (registered trademark) MD1537 manufactured by Kraton Polymer Co., Ltd. is used, and MD1537 has an olefinic double bond amount of 0.1 mmol/g, a styrene unit content of 60% by mass, The refractive index is 1.54, the weight average molecular weight is 136,000, and the number average molecular weight is 106,000. In Example 3, Kraton (registered trademark) A1536 manufactured by Kraton Polymer Co., Ltd. is used. A1536 is an olefinic double bond amount of 0.1 mmol/g, a styrene unit content of 42 mass%, a refractive index of 1.52, and a weight average. The molecular weight is 135,000 and the number average molecular weight is 101,000. In Example 4, two types of SEBS triblock copolymers are used in addition to the above-mentioned Tuftec (registered trademark) P1083. H1051 has an olefinic double bond amount of 0.38 mmol/g and a styrene unit content of 39. 9 mass %, refractive index 1.524, weight average molecular weight 25,000, number average molecular weight 195,000, H1043 is olefinic double bond amount 0.3 mmol/g, styrene unit content 65.6. It has a mass%, a refractive index of 1.554, a weight average molecular weight of 141,000 and a number average molecular weight of 58,000.

In Example 2, the conversion rate of MMA calculated from the amount of residual monomers in the polymerization reaction solution was 90.5%, the conversion rate of CMI was 99.3%, and the conversion rate of St was 98.4%. .. The composition ratio (mass basis) of the acrylic copolymer chain bonded to the SEBS triblock copolymer chain and the acrylic copolymer calculated from the conversion ratio was MMA:CMI:St=38.9:15. 7:45.4, and the content of ring structural units in the resin composition was 11.8% by mass.

In Example 3, the MMA conversion rate calculated from the amount of residual monomers in the polymerization reaction solution was 92.0%, the CMI conversion rate was 98.5%, and the St conversion rate was 99.1%. .. The composition ratio (mass basis) of the acrylic copolymer chain bonded to the SEBS triblock copolymer chain and the acrylic copolymer calculated from the conversion rate was MMA:CMI:St=61.4:12. 0.5:26.1, and the content of ring structural units in the resin composition was 10.6% by mass.

In Example 4, the conversion rate of MMA calculated from the amount of residual monomer in the polymerization reaction solution was 91.1%, the conversion rate of PMI was 94.0%, and the conversion rate of St was 98.7%. .. The composition ratio (mass basis) of the acrylic copolymer chain bonded to the SEBS triblock copolymer chain and the acrylic copolymer calculated from the conversion rate was MMA:PMI:St=64.5:10. 0.1:25.4, and the content of ring structural units in the resin composition was 8.6% by mass.

In Example 5, the conversion rate of MMA calculated from the amount of residual monomers in the polymerization reaction solution was 90.1%, the conversion rate of CMI was 96.4%, and the conversion rate of St was 98.4%. .. The composition ratio (mass basis) of the acrylic copolymer chain bonded to the SEBS triblock copolymer chain and the acrylic copolymer calculated from the conversion rate was MMA:CMI:St=61.1:12. 0.4:26.4, and the content of ring structural units in the resin composition was 9.3 mass %.

In Comparative Example 1, the conversion rate of MMA calculated from the amount of residual monomers in the polymerization reaction solution was 94.0%, the conversion rate of CMI was 96.8%, and the conversion rate of St was 99.1%. .. The composition ratio (mass basis) of the acrylic copolymer chain bonded to the SEBS triblock copolymer chain and the acrylic copolymer calculated from the conversion ratio was MMA:CMI:St=62.0:12. The ratio of the ring structure unit in the resin composition was 12.1% by mass.

In Comparative Example 2, the conversion rate of MMA calculated from the amount of residual monomer in the polymerization reaction solution was 93.6%, the conversion rate of CMI was 97.1%, and the conversion rate of St was 99.1%. .. The composition ratio (mass basis) of the acrylic copolymer chain bonded to the SEBS triblock copolymer chain and the acrylic copolymer calculated from the conversion rate was MMA:CMI:St=86.4:12. The ratio of the ring structure unit in the resin composition was 12.4% by mass.

<Example 1-A>
The resin composition obtained in Example 1 was hot press molded at 250° C. to prepare an unstretched film having a thickness of 70 μm. The obtained unstretched film was cut into a size of 100 mm×110 mm to prepare a test piece. Using an autograph with a thermostat (Shimadzu Corporation, AG-X 1kN), the distance between chucks was 80 mm, and the stretching ratio was 2.5 times at a stretching speed of 80 mm/min at a temperature of Tg+4°C. The piece was subjected to free-end uniaxial stretching, annealed for 1 minute and then cooled to obtain a stretched film having a thickness of 40 μm.

<Example 1-B to Example 5-C, Comparative Example 1-A to Comparative Example 2-B>
A stretched film was produced in the same manner as in Example 1-A, except that the resin composition shown in Table 1 was used and the draw ratio was changed to the draw ratio shown in Table 1. The thickness of the unstretched film was adjusted so that the stretched film had a thickness of 40 μm.

The results of Examples and Comparative Examples are summarized in Table 1 below.

Claims (10)

A polymer chain (A) having a unit derived from a diene and/or an olefin, and a polymer chain (B) having a unit (b1) derived from a (meth)acrylic monomer and a unit (b2) having a ring structure in its main chain. A resin composition containing and
A resin composition, wherein the stress optical coefficient Cr of the resin composition is −25.0×10 ⁻¹¹ Pa ⁻¹ or more and −4.0×10 ⁻¹¹ Pa ⁻¹ or less. A stretched film having a thickness of 40 μm obtained by subjecting an unstretched film obtained from the resin composition to free-end uniaxial stretching at a draw ratio of 2 at a temperature 4° C. higher than the glass transition temperature of the resin composition, The resin composition according to claim 1, which has a folding endurance of 10 times or more by a MIT test according to JIS P 8115 in the direction. A stretched film obtained by subjecting an unstretched film obtained from the resin composition to free-end uniaxial stretching at a draw ratio of 2 at a temperature 4° C. higher than the glass transition temperature of the resin composition, with respect to light having a wavelength of 589 nm. The resin composition according to claim 1, wherein the in-plane retardation Re per thickness of 40 μm is 30 nm or more. The resin composition according to claim 1, wherein a melt flow rate measured according to JIS K 7210 B method at a temperature of 240° C. and a load of 10 kgf is 10 to 40 g/10 minutes. The resin composition according to any one of claims 1 to 4, further comprising a (meth)acrylic polymer (Q) having a unit derived from a (meth)acrylic monomer and a unit having a ring structure in the main chain. Stuff. The polymer chain (A) has a polymer block (a1) having a unit derived from a diene and/or an olefin, and a polymer block (a2) having a unit derived from an aromatic vinyl monomer. The resin composition according to any one of 5 above. The resin composition according to claim 6, wherein the polymer chain (B) is grafted onto the polymer block (a1) of the polymer chain (A). The resin composition according to any one of claims 1 to 7, wherein the polymer chain (B) further has a vinyl monomer-derived unit (b3) copolymerizable with the (meth)acrylic monomer. Stuff. A film containing the resin composition according to claim 1. A method for producing a resin composition in which a (meth)acrylic monomer is polymerized in the presence of a polymer having a diene and/or olefin-derived unit, wherein the resin composition has a stress optical coefficient Cr of -25. method for producing a 0 × 10 ^-11 Pa ^-1 or -4.0 × 10 ^-11 Pa ^-1 or less is a resin composition.