JP7096720B2 - the film - Google Patents

Description

The present invention relates to a film.

In recent years, there has been a demand for image display devices to use optical materials having high optical characteristics in order to improve the sharpness of images. Small birefringence is required as one of the advanced optical characteristics. In general, a polymer compound used as an optical material has a different refractive index in the main chain direction of the molecule and a refractive index in the direction perpendicular to the main chain direction, so that double refraction occurs. As a method for reducing birefringence, that is, a method for reducing the phase difference, for example, Patent Document 1 describes an acrylic copolymer having a lactone ring structure that gives a positive phase difference and a structural unit that gives a negative phase difference. Acrylic copolymers which are coalesced and have a phase difference of 20 nm or less are disclosed. Further, Patent Document 2 discloses a film formed from a resin composition in which a flexible resin having a low glass transition temperature is blended with a (meth) acrylic resin having a ring structure in the main chain. Patent Document 3 discloses a resin composition containing a core-shell rubber having a negative orientation birefringence in a lactone ring having a positive orientation birefringence.

Japanese Unexamined Patent Publication No. 2007-63541 Japanese Unexamined Patent Publication No. 2007-100044 JP-A-2007-254726

Patent Document 1 merely describes the phase difference control in the copolymer, and does not consider the phase difference control when the rubber component is added for the purpose of imparting strength. In Patent Document 2, when strength is imparted by biaxial stretching, there is a problem that anisotropy of strength occurs due to a stretching ratio or the like. Moreover, the phase difference of the flexible resin was not taken into consideration. In Patent Document 3, both positive birefringence and negative birefringence depend on the orientation, and since the values of both are linked, it is difficult to control each individually, and it is obtained from such a resin composition. Strict control from the component side is indispensable for reducing the phase difference of the entire film, which is complicated.

The present invention has been made by paying attention to the above circumstances, and an object of the present invention is to provide a film having a very small phase difference by a simple means.

The present inventors have completed the present invention by using a film having a phase-separated structure and having negative orientation birefringence introduced into the matrix.

That is, the present invention includes the following inventions.

1. 1. A film in which a phase-separated portion is formed in a matrix, which has positive morphological birefringence based on the phase-separated structure, negative oriented birefringence is introduced into the matrix, and morphological birefringence and oriented birefringence are formed. Films that cancel each other out.

2. 2. A film in which a phase-separated structure is formed in the matrix and the matrix contains a resin (R) having negative orientation birefringence, and the in-plane phase difference Re with respect to light having a wavelength of 589 nm of the film is A film having a wavelength of 10 nm or less and having a phase difference Rth in the thickness direction with respect to light having a wavelength of 589 nm of -10 to 10 nm.

3. 3. The stress optical coefficient Cr of the resin (R) is -30.0 × 10 ^-9 Pa ^-1 or more and −0.1 × 10 ^-9 Pa ^-1 or less. The film described in.

4. The above 2. The resin (R) contains the (meth) acrylic polymer (Q). Or the above 3. The film described in.

5. The film comprises a polymer chain having a polymer block (a1) having a unit derived from a diene and / or an olefin. ~ 4. The film described in any of.

6. The film is a copolymer having a polymer chain (A) 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. The above 1. ~ 4. The film described in any of.

7. 6. The polymer chain (A) is contained in the film in an amount of 0.1 to 20% by mass. The film described in.

8. Having a glass transition temperature above 115 ° C. 1. ~ 7. The film described in any of.

9. The internal haze is 1.0% or less. ~ 8. The film described in any of.

10. 1. The film is a biaxially stretched film having a thickness of 60 μm or less. ~ 9. The film described in any of.

Since the phase difference of the film of the present invention is controlled by the phase separation structure, the phase difference can be easily reduced.

6 is a scanning electron micrograph showing the sea-island structure of the film in Example 1.

The present invention relates to a film in which negative birefringence is introduced into the matrix (the matrix contains a resin (R) having negative birefringence). A phase-separated structure is formed in the matrix of the film, and the phase-separated structure exhibits positive morphological birefringence, so that the oriented birefringence and the morphological birefringence cancel each other out, and the phase difference of the film can be easily obtained. Can be made very small. Hereinafter, "the phase difference is very small", "alignment birefringence", "morphological birefringence", and "phase separation structure" will be described.

In the film of the present invention, the in-plane retardation Re with respect to light having a wavelength of 589 nm is preferably 10 nm or less, and the phase difference Rth in the thickness direction with respect to light having a wavelength of 589 nm is preferably -10 to 10 nm. The phrase "the phase difference is very small" refers to a film that meets the above conditions. It is more preferable that the in-plane phase difference Re is 0 nm or more and 5.0 nm or less, and the thickness direction phase difference Rth is −5.0 nm or more and 10 nm or less, and the in-plane phase difference Re is 0 nm or more and 2.0 nm or less, and the thickness direction phase difference is It is more preferable that Rth is 0 nm or more and 7.0 nm or less. A film showing such in-plane phase difference Re and phase difference Rth in the thickness direction has good viewing angle characteristics and contrast characteristics, and can be suitably applied to an image display device such as a liquid crystal display. Become. The in-plane phase difference Re and the phase difference Rth in the thickness direction are obtained by the method described in the examples.

Oriented birefringence is generally birefringence that occurs when the main chain of a chain polymer (polymer chain) is oriented, and when the stress optical coefficient Cr of a predetermined resin is negative, the above-mentioned predetermined resin is used. Is referred to as a resin having negative orientation birefringence. The stress optical coefficient Cr of the resin (R) is preferably -30.0 × 10 ^-9 Pa ^-1 or more and −0.1 × 10 ^-9 Pa ^-1 or less, preferably -22.0 × 10 ^-9 Pa ⁻ . It is more preferably ¹ or more and -1.0 × 10 ^-9 Pa ^-1 or less, and further preferably -10.0 × 10 ^-9 Pa ^-1 or more and -2.0 × 10 ^-9 Pa ^-1 or less. preferable. By setting the stress optical coefficient Cr of the resin (R) to -30.0 × 10 ^-9 Pa ^-1 or more, the positive morphological birefringence and the negative oriented birefringence can cancel each other out, so that the film position. The phase difference can be made very small. The stress optical coefficient of the resin (R) is determined by the method described in Examples.

The phase difference of the film matrix itself is the phase difference of the film made in the absence of phase separation (ie, the absence of components involved in morphological birefringence), for example, the film made only of the resin having negative orientation birefringence. It can be defined by the phase difference (hereinafter, may be referred to as a matrix equivalent film), and the thickness direction phase difference Rth of the matrix equivalent film is less than 0 nm. Further, the in-plane retardation Re of the matrix-equivalent film is preferably 10 nm or less, the thickness direction retardation Rth is preferably -30 nm or more and less than 0 nm, the in-plane retardation Re is 0 nm or more and 5.0 nm or less, and the thickness direction retardation. Rth is more preferably -20 nm or more and less than 0 nm, in-plane retardation Re is more preferably 0 nm or more and 3.0 nm or less, and thickness direction retardation Rth is more preferably -10.0 nm or more and less than 0 nm. It is particularly preferable that the phase difference Re is 0 nm or more and 1.0 nm or less, and the thickness direction retardation Rth is −5.0 nm or more and less than 0 nm. By setting the thickness direction retardation Rth to -30 nm or more and less than 0 nm, this negative orientation birefringence can be canceled by the positive morphological birefringence, and the phase difference of the film can be easily reduced. The in-plane phase difference Re and the phase difference Rth in the thickness direction of the matrix-corresponding film are obtained by the method described in Examples.

Morphological birefringence is the birefringence exhibited by a material that has structures that are much larger than the molecule and smaller than the wavelength of light, either periodically or collectively, and if it has that birefringence, The morphological birefringence is always a positive value. The degree of phase difference corrected by morphological birefringence in the film is greater than 0 nm in the thickness direction phase difference Rth. The degree of the phase difference corrected by the morphological birefringence is preferably −5.0 nm or more and 0 nm or less for the in-plane retardation Re of the film, and more than 0 nm and 30 nm or less for the thickness direction retardation Rth. It is more preferable that the phase difference Re is -2.0 nm or more and 0 nm or less, the thickness direction retardation Rth is larger than 0 nm and 15 nm or less, the in-plane retardation Re is -0.5 nm or more and 0 nm or less, and the thickness direction retardation Rth is 0 nm. It is more preferably larger and 10 nm or less. The value obtained by subtracting the in-plane retardation Re or the thickness direction retardation Rth of the matrix-equivalent film from the in-plane retardation Re or the thickness direction retardation Rth of the film of the present invention is corrected by morphological birefringence, respectively. It is defined as the in-plane phase difference Re or the phase difference Rth in the thickness direction.

As used herein, the term "phase-separated structure" refers to a state in which two or more phases are formed when the film is observed with a scanning electron microscope (SEM). The phase separation structure is formed by molding a film from this resin mixture using a resin (R) exhibiting negative orientation birefringence and a resin (S) having a portion incompatible with the resin (R). Can be done.

Examples of the phase-separated structure include a sea-island structure, a continuous spherical structure, a composite dispersed phase structure, and a co-continuous phase structure. The sea-island structure is a structure in which a small-volume dispersed phase (island structure) is dispersed in a continuous phase (sea structure), and a particulate or spherical dispersed phase (island structure) is contained in a continuous phase (sea structure). It is a scattered structure. The continuous spherical structure is a structure in which substantially spherical dispersed phases are connected and dispersed in the continuous phase. The composite dispersed structure is a structure in which dispersed phases are scattered in a continuous phase, and further, resins constituting the continuous phase are scattered in the dispersed phase. The co-continuous structure is a structure in which a continuous phase and a dispersed phase form a complicated three-dimensional network.
The film of the present invention has a phase-separated structure, so that a continuous phase containing a resin (R) having a negative oriented birefringence and a dispersed phase having a positive morphological birefringence can be used for oriented birefringence and morphological birefringence. Will cancel each other out, and the phase difference of the film can be easily made very small.

The film of the present invention preferably has a sea-island structure, and the island size in the structure is preferably 450 nm or less, more preferably 400 nm or less, further preferably 350 nm or less, and particularly preferably 300 nm or less. The film showing the sea-island structure tends to be highly transparent. The lower limit of the island size of the sea island structure is not particularly limited, and may be, for example, 10 nm or more, 50 nm or more, or 100 nm or more. The sea-island structure of the film is observed by a scanning electron microscope (STEM), and the method described in Examples is referred to as a specific measurement method.

1. 1. Resin (S)
The resin (S) preferably contains a polymer chain having a polymer block (a1) having a unit derived from a diene and / or an olefin. When the film of the present invention has a sea-island structure, the island structure is due to a polymer chain having a polymer block (a1). The resin (S) has a common weight having a polymer chain (A) 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. A polymer chain (A) 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, more preferably containing a coalescence. , It is more preferable to contain a copolymer (P) having a polymer chain (B) having a unit derived from the (meth) acrylic monomer. The polymer (P) contains a polymer chain (A) having a polymer block (a1) that functions as a soft component and a polymer block (a2) that functions as a hard component, so that the mechanical strength is enhanced. The resin composition containing such a copolymer (P) has high mechanical strength (for example, folding resistance (MIT strength)). Further, transparency and heat resistance are enhanced by containing the polymer chain (B), and the resin composition containing such a copolymer (P) has high transparency and high mechanical strength (for example, folding resistance). (MIT strength)) can be compatible.

The copolymer (P) preferably contains 2 to 30% by mass of the polymer chain (A), more preferably 3 to 20% by mass, and even more preferably 5 to 10% by mass. If it is less than 2% by mass, the effect of improving the mechanical strength expected as a soft component may not be sufficient, which is not preferable. If it is more than 30% by mass, aggregation of the dispersed phase is likely to occur and the transparency may be lowered. The resin composition containing such a copolymer (P) can achieve both high transparency and high mechanical strength, and cancels the negative birefringence derived from the resin (R) in the film on which the phase-separated structure is formed. A positive morphological birefringence can be expressed.

Examples of the diene forming the diene-derived unit of the polymer block (a1) include 1,3-butadiene (also known as butadiene), 2-methyl-1,3-butadiene (also known as isoprene), and 1,3-pentadiene. Arcadiens such as 1,4-pentadiene, 1,5-hexadiene and 2,5-dimethyl-1,5-hexadiene (also known as diisobutene) are preferably used, among which 1,3-butadiene, 2-methyl-1, Conjugate diene such as 3-butadiene and 1,3-pentadiene is more preferable.
Examples of the olefin forming the olefin-derived unit of the polymer block (a1) include ethylene, propylene, 1-butene, isobutene, 2-methyl-1-butene, 3-methyl-1-butene, 1-tetradecene and 1-. Monoolefins such as octadecene (also referred to as alkenes) are preferably used, and among them, α-olefins, which are alkenes having a carbon-carbon double bond at the α-position, are more preferable. The carbon number of these dienes and olefins is preferably 2 or more, more preferably 3 or more, more preferably 20 or less, still more preferably 10 or less, still more preferably 6 or less.

Units derived from dienes and / or olefins are defined as units formed by the polymerization of dienes and / or olefins. The unit derived from the olefin is not limited to the one actually formed by homopolymerization or copolymerization of the olefin as long as the same structure is formed, and the unit derived from the diene may be formed by hydrogenation (note that). , In the present specification, "monopolymer or copolymer" is referred to as "single / copolymer", and "monopolymer or copolymer" is referred to as "(single / copolymer) polymer". It may be written). The polymer block (a1) contains, as units 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 (single / co) polymers such as polyethylene, polypropylene, polybutene-1, ethylene-propylene copolymer, and ethylene-butene copolymer; polyisoprene, polybutadiene, and isoprene-. Diene (single / co) polymers such as butadiene copolymers; olefin and diene copolymers such as ethylene-propylene-diene copolymers and isobutene-isoprene copolymers can be mentioned. The α-olefin (single / co) polymer is preferable as the olefin (single / co) polymer, and the conjugated diene (single / co) polymer is preferable as the diene (single / co) polymer. As the polymer, a copolymer of α-olefin and conjugated diene is preferable. Among these, a copolymer of α-olefin and conjugated diene such as polyisoprene and isobutene-isoprene copolymer, polyethylene and polypropylene are more preferable.

The polymer block (a1) may have units derived from other unsaturated monomers in addition to units derived from diene and / or olefin. The other unsaturated monomer is not particularly limited as long as it is a compound having a polymerizable double bond, and is, for example, a vinyl ester such as vinyl acetate or vinyl propionate; (meth) acrylic acid, maleic anhydride, (meth). ) Saturated carboxylic acids such as methyl acrylate and ethyl (meth) acrylate and their esters; vinyl silanes such as vinyltrimethoxysilane, 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 in which a vinyl group is bonded to an aromatic ring, and is, for example, styrene, vinyltoluene, methoxystyrene, α-methylstyrene, α-hydroxymethylstyrene, α-hydroxyethyl. Styrene-based monomer such as styrene; Polycyclic aromatic hydrocarbon ring vinyl monomer such as 2-vinylnaphthalene; Aromatic heterocyclic vinyl simpler such as N-vinylcarbazole, 2-vinylpyridine, vinylimidazole, vinylthiophene, etc. Quantum and the like can be mentioned. Among 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 a polymerizable double-bonded carbon of styrene or a benzene ring, and the substituent includes an alkyl group, an alkoxy group, and the like. 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 are preferably 1 to 4 carbon atoms, more preferably 1 to 2 carbon atoms, and the alkyl group and alkoxy group bonded to styrene have at least a part of hydrogen atoms of a hydroxy group or a halogen. It may be substituted with a group. From the viewpoint of reducing the coloring of the copolymer (P), the styrene-based monomer preferably has no amino group. Further, the styrene-based monomer is preferably an 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 an 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 made into the polymer block (a1), the transparency of the copolymer (P) can be easily enhanced. For example, even when the difference in refractive index between the polymer chain (A) and the polymer chain (B) of the copolymer (P) is large, it becomes easy to increase the transparency of the copolymer (P).

When the polymer block (a1) has a unit derived from the aromatic vinyl monomer, the content ratio of the unit derived from the aromatic vinyl monomer may be 1% by mass or more in the polymer block (a1). Preferably, 2% by mass or more is more preferable, 3% by mass or more is further preferable, 40% by mass or less is preferable, 35% by mass or less is more preferable, and 30% by mass or less is further preferable. In this case, the total content of the diene and / or olefin-derived unit and the aromatic vinyl monomer-derived unit in the polymer block (a1) is preferably 70% by mass or more, preferably 80% by mass or more. Is more preferable, and 90% by mass or more is further preferable. The polymer block (a1) may be substantially composed of only units derived from diene and / or olefins and units derived from aromatic vinyl monomers, for example, the total content of these units is 99% by mass. It may be the above.

If the polymer block (a1) has units derived from other unsaturated monomers in addition to units derived from diene and / or olefins, the polymer block (a1) will be these monomers. It is preferably a random copolymer of.

The polymer block (a1) preferably contains a unit derived from diene and / or olefin as a main component, and the content ratio of the unit derived from diene and / or olefin is 50 in 100% by mass of the polymer block (a1). It is preferably 7% by mass or more, more preferably 60% by mass or more, and further preferably 70% by mass or more. The polymer block (a1) may be composed substantially only of units derived from diene and / or olefin, and may have, for example, units derived from diene and / or olefin in an amount of 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 monomer exemplified in the above-mentioned polymer block (a1).

The polymer block (a2) may have a unit derived from another unsaturated monomer in addition to the unit derived from the aromatic vinyl monomer. The other unsaturated monomer is not particularly limited as long as it is a compound having a polymerizable double bond, and is, for example, a vinyl ester such as vinyl acetate or 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 (particularly a random copolymer) of these other unsaturated monomers and an aromatic vinyl monomer. The content of the diene and / or olefin-derived unit 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. It is preferable not to do so.

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 of only units derived from the aromatic vinyl monomer, for example, the content ratio of the units derived from the aromatic vinyl monomer is 99% by mass or more. May be good.

Examples of the polymer chain (A) composed of the polymer block (a1) and the polymer block (a2) include a styrene-butadiene block copolymer, a styrene-butadiene-styrene block copolymer, and a styrene-butadiene-. Hydrohydrates of styrene block copolymers (eg, styrene-ethylene / butylene-styrene block copolymers (SEBS), styrene-butadiene / butylene-styrene block copolymers), styrene-isoprene block copolymers, styrene- Examples thereof include isoprene-styrene block copolymers, hydrogenated products of styrene-isoprene-styrene block copolymers (for example, styrene-ethylene / propylene-styrene block copolymers (SEPS)) and the like. Moreover, in these block copolymers, the butadiene block becomes a butadiene / styrene block, and the isoprene block becomes an isoprene / styrene block. In the above notation, each block is classified 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 bonded to both sides of the polymer block (a1). As a result, the polymer chain (A) functions as an elastomer, and the mechanical strength of the copolymer (P) can be further increased. In this case, the polymer chain (A) may be a triblock copolymer, a multi-block copolymer, or a radial block copolymer, but of the polymer chain (A). A triblock copolymer is preferable because the characteristics can be easily controlled and the polymer chain (B) can be easily introduced into the polymer (P). Examples of such a copolymer include a styrene-butadiene-styrene block copolymer and its hydrogenated product, a styrene-isoprene-styrene block copolymer and its hydrogenated product, and the like.

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, preferably 10% by mass or more. More preferably, 15% by mass or more is further preferable, 55% by mass or less is preferable, 50% by mass or less is more preferable, 45% by mass or less is further preferable, 35% by mass or less is particularly preferable, and 25% by mass or less is most preferable. .. As a result, 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 copolymer (P). From the same viewpoint, the content ratio of the polymer block (a1) in the polymer chain (A) is preferably 45% by mass or more, more preferably 50% by mass or more, further preferably 55% by mass or more, and 65% by mass. % Or more is particularly preferable, 75% by mass or more is most preferable, 95% by mass or less is preferable, 90% by mass or less is more preferable, and 85% by mass or less is further preferable. The content of the unit derived from the aromatic vinyl monomer in the polymer chain (A) may be 0% by mass, preferably 5% by mass or more, more preferably 10% by mass or more, and 15% by mass. % Or more is further preferable, 55% by mass or less is preferable, 50% by mass or less is more preferable, 45% by mass or less is further preferable, 35% by mass or less is particularly preferable, and 25% by mass or less is most preferable.

The weight average molecular weight of the polymer chain (A) is preferably 10,000 or more, more preferably 5,000 or more, further preferably 10,000 or more, still more preferably 30,000 or more, and preferably 300,000 or less. 250,000 or less is more preferable, and 200,000 or less is further preferable. By setting the weight average molecular weight of the polymer chain (A) in such a range, it becomes easy to secure the mechanical strength of the copolymer (P) and improve the formability of the copolymer (P). ..

The copolymer (P) may have the polymer chain (B). The polymer chain (B) has at least a unit derived from a (meth) acrylic monomer (hereinafter, may be referred to as “(meth) acrylic unit”). By having the polymer chain (B), the transparency of the copolymer (P) can be enhanced.

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 β-position. The alkyl group may have at least a part of a hydrogen atom 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. Further, the (meth) acrylic monomer contains (meth) acrylic acid (that is, a free acid) and a derivative thereof, and the derivative includes an ester, a salt, an acid amide 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 an oxygen atom of an ester bond of (meth) acrylic acid. Can be mentioned.

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. , (Meta) isoamyl acrylate, (meth) n-hexyl acrylate, (meth) 2-ethylhexyl acrylate, (meth) heptyl acrylate, (meth) octyl acrylate, (meth) decyl acrylate, (meth) ) Dodecyl acrylate, pentadecyl (meth) acrylate, hexadecyl (meth) acrylate, heptadecyl (meth) acrylate, octadecyl (meth) acrylate and the like are 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, the description of "C1-18" and "C1-12" means "carbon number 1-18" and "carbon number 1-12", respectively.

Examples of the (meth) acrylic acid ester having a cyclic aliphatic hydrocarbon group include (meth) cyclopropyl acrylate, cyclobutyl (meth) acrylate, cyclopentyl (meth) acrylate, and cyclohexyl (meth) acrylate. ) Cycloalkyl acrylate; Cross-linked ring-type (meth) acrylate such as isobornyl (meth) acrylate can be mentioned. The cycloalkyl group of 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 (meth) phenylacrylic acid, trill (meth) acrylic acid, xylyl (meth) acrylic acid, naphthyl (meth) acrylate, and binaphthyl (meth) acrylic acid. , (Meta) aryl (meth) acrylate such as anthryl (meth) acrylate; (meth) aralkyl (meth) acrylate such as benzyl (meth) acrylate; (meth) aryloxyalkyl (meth) acrylate such as phenoxyethyl (meth) acrylate. Can be mentioned. The aryl group of the aryl (meth) acrylate is preferably a C6-20 aryl group, more preferably a C6-14 aryl group. The aralkyl group of aralkyl (meth) acrylate is preferably a C6-10 aryl C1-4 alkyl group. As the aryloxyalkyl group of the aryloxyalkyl (meth) acrylate, a C6-10 aryloxy C1-4 alkyl group is preferable, and a phenoxy C1-4 alkyl group is more preferable.

The (meth) acrylic acid ester may have a substituent such as a hydroxy group, an amino group, a halogen group, an alkoxy group, or an epoxy group. In particular, in a (meth) acrylic acid ester having a linear or branched aliphatic hydrocarbon group, it is preferable that the aliphatic hydrocarbon group has a hydroxy group, an amino group, a halogen group, an alkoxy group, an epoxy group and the like. Examples of such (meth) acrylic acid esters include (meth) hydroxyalkyl acrylates such as 2-hydroxyethyl (meth) acrylate; and (meth) chloromethyl acrylate, 2-chloroethyl (meth) acrylate and the like. Alkyl halides such as (meth) acrylate: alkoxyalkyl (meth) acrylate such as 2-methoxyethyl (meth) acrylate; epoxyalkyl (meth) acrylate such as glycidyl (meth) acrylate can be mentioned. As the alkyl group of (meth) hydroxyalkyl acrylate and epoxyalkyl (meth) acrylate, a C1-12 alkyl group is preferable, and a C1-6 alkyl group is more preferable. The alkoxyalkyl group of the (meth) alkoxyalkyl acrylate is preferably a C1-12 alkoxy C1-12 alkyl group, more preferably C1-6 as the alkoxy group, and more preferably C1-6 as the alkyl group.

The (meth) acrylic monomer also includes a monomer exemplified by the (meth) acrylic monomer A having a protonic hydrogen atom-containing group, the (meth) acrylic monomer B, etc., which will be described later. ..

The polymer chain (B) preferably has a ring structure in the main chain. That is, it is preferable that the polymer chain (B) has a unit having a ring structure in the main chain of the polymer chain (B) (hereinafter, may be referred to as a “ring structure unit”). Since the polymer chain (B) has a ring structure in the main chain, the transparency and heat resistance of the resin composition containing the copolymer (P) can be enhanced. Further, improvement of solvent resistance, dimensional stability, surface hardness, adhesiveness, barrier property of oxygen and water vapor, and various optical characteristics can be expected. Further, when a stretched film is obtained from the resin composition, it is possible to develop a phase difference due to the ring structure of the polymer chain (B) depending on the stretching conditions.

The ring structure of the main chain of the polymer chain (B) may contain 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, a part or all of the (meth) acrylic monomer contains a component (also referred to as a ring structure forming monomer) necessary for forming a ring structure in the main chain of the polymer chain in the ring structure. In this case, for example, two carboxylic acid groups of units derived from adjacent (meth) acrylic monomers may be linked by acid anhydrideization, imidization, or the like. When one of the units derived from the adjacent (meth) acrylic monomer has a protonic hydrogen atom-containing group such as a hydroxy group or an amino group, it is derived from this one (meth) acrylic monomer. A ring structure can also be formed by condensing a protonic hydrogen atom-containing group of a unit with a carboxylic acid group of a unit derived from the other (meth) acrylic monomer. When the ring structure is introduced separately from the unit derived from the (meth) acrylic monomer, for example, a (meth) acrylic monomer and a monomer having a polymerizable double bond in the ring structure are introduced. It may be copolymerized.

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

The ring structure includes a lactone ring structure, a lactam ring structure, a cyclic imide structure (for example, succinimide structure, glutarimide structure, etc.), and a cyclic anhydride structure (for example, succinic anhydride) from the viewpoint of heat resistance of the copolymer (P). Acid structure, glutaric anhydride structure, etc.) are preferably mentioned. Only one kind of these ring structures may be contained in the main chain of the polymer chain (B), or two or more kinds thereof may be contained. Among these, at least one selected from a lactone ring structure, a succinimide structure, a succinic anhydride structure, a glutarimide structure, and a glutaric anhydride structure is preferable, and a lactone ring structure is more preferable.

When the polymer chain (B) has a lactone ring structure or a lactam ring structure as the ring structure of the main chain, the number of ring members of the lactone ring structure or the lactam ring structure is not particularly limited, and for example, any of a 4-membered ring to an 8-membered ring. It should be. From the viewpoint of excellent stability of the ring structure, 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.

Examples of the lactone ring structure include structures disclosed in JP-A-2004-168882, but the lactone ring structure can be easily introduced, specifically, a precursor (weight before lactone cyclization). (Combined) has a high polymerization yield, the lactone ring content in the cyclization condensation reaction of the precursor can be increased, and a polymer having a unit derived from (meth) acrylate can be used as the precursor. The structure represented by the formula (1a) is preferably shown. Further, 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 independently represent a hydrogen atom or a substituent, respectively.

Examples of the substituent of the formula (1a) and the formula (1b) of R ¹ , R ² and R ³ include organic residues such as a hydrocarbon group, and for example, C1-20 which may have a substituent. Hydrocarbon groups and the like can be mentioned. 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 (preferably a C1-10 alkyl group, more preferably a C1-6 alkyl) such as a methyl group, an ethyl group, an n-propyl group and an isopropyl 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. Examples thereof include a group (preferably a C4-12 cycloalkyl group, more preferably a C5-8 cycloalkyl group) and the like. Examples of the aromatic hydrocarbon group include a C6-20 aryl group (preferably a C6-14 aryl group, more preferably a C6-10) such as a phenyl group, a trill group, a xsilyl group, a naphthyl group and a biphenyl 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, and specifically, one or more of the 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 derived from the viewpoint that it is easy to obtain a copolymer (P) having excellent heat resistance and a small double refractive index. It is preferable that R ³ is a hydrogen atom or a methyl group independently, and R ¹ and R ² are independently hydrogen atoms or a methyl group, respectively, and R ³ is a hydrogen atom or a methyl group. It is more preferably a hydrogen atom or a methyl group.

A protonic hydrogen atom-containing group having a protonic hydrogen atom-containing group such as a hydroxy group or an amino group and a unit derived from the (meth) acrylic monomer A, and a unit derived from the (meth) acrylic monomer A. A lactone ring structure and / or a lactam ring structure can be introduced into the polymer chain (B) by cyclizing and condensing with an ester group of a unit derived from an adjacent (meth) acrylic acid ester. As a polymerization component, a (meth) acrylic monomer A having a protonic hydrogen atom-containing group such as a hydroxy group or an amino group is indispensable, and the (meth) acrylic monomer B includes the monomer A. do. Monomer B may or may not coincide with monomer A. When the monomer B coincides with the monomer A, the monomer A is homopolymerized.

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

As the (meth) acrylic monomer A2 having an amino group, a compound in which the hydroxy group of the monomer A1 is changed to an amino group can be exemplified. When the polymer chain (B) has a lactone ring structure and / or a lactam ring structure, the (meth) acrylic monomer A becomes a ring structure forming monomer.

As the (meth) acrylic monomer B, a monomer having a vinyl group and an ester group or a carboxy group is preferable, and for example, (meth) acrylic acid and alkyl (meth) acrylic acid (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) 2- (Hydroxymethyl) alkyl acrylate and the like, 2- (hydroxyethyl) alkyl acrylate such as 2- (hydroxyethyl) methyl acrylate) and the like can be mentioned.

The polymer chain (B) may have only one type of lactone ring structure or lactam structure represented by the formula (1a) or the 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 the ring structure of the main chain, succinic anhydride is used. As the structure or the succinimide structure, the structure represented by the following formula (2) is preferably shown. In the following formula (2), R ⁴ and R ⁵ 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 When is an oxygen atom, n1 = 0, and when X ¹ is a nitrogen atom, n1 = 1.

Examples of the substituent of R ⁶ in the formula (2) include organic residues such as a hydrocarbon group, and examples thereof include a hydrocarbon group of C1-20 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 (preferably a C1-10 alkyl group, more preferably a C1-6 alkyl) such as a methyl group, an ethyl group, an n-propyl group and an isopropyl 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. Examples thereof include a group (preferably a C4-12 cycloalkyl group, more preferably a C5-8 cycloalkyl group) and the like. Examples of the aromatic hydrocarbon group include a C6-20 aryl group (preferably a C6-14 aryl group, more preferably a C6-10) such as a phenyl group, a trill group, a xsilyl group, a naphthyl group and a biphenyl 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 a 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), for example, by copolymerizing maleic anhydride with a (meth) acrylic monomer (eg, (meth) acrylic acid ester, etc.). .. When the polymer chain (B) has a succinic anhydride structure, maleic anhydride is a monomer for forming a ring structure.

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), for example, by copolymerizing an N-substituted maleimide with a (meth) acrylic monomer (eg, a (meth) acrylic acid ester). Examples of the succinimide structure include a succinimide structure in which the N position is unsubstituted, 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. The structure and the like can be mentioned. Further, as the maleimide that gives the succinimide structure, maleimide in which the N position is substituted, N-methylmaleimide, N-ethylmaleimide, N-cyclohexylmaleimide, N-phenylmaleimide, N-naphthylmaleimide, N-benzylmaleimide and the like are used. be able to. When the polymer chain (B) has a succinimide structure, the N-substituted maleimide becomes 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 have excellent heat resistance and it is easy to obtain a copolymer (P) having a small double refractive index. It is a hydrogen atom, R ⁶ 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 cyclohexyl. More preferably, it is a group or a phenyl group.

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 an anhydrous glutaric acid structure as the ring structure of the main chain, the structure represented by the following formula (3) is preferably shown as the glutarimide structure or the anhydrous glutaric acid structure. In the following formula (3), R ⁷ and R ⁸ 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 When is an oxygen atom, n2 = 0, and when X ² is a nitrogen atom, n2 = 1.

In the 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. C1-8 such as 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. Examples thereof include an alkyl group. Since it is easy to obtain a copolymer (P) having excellent heat resistance and a small double refractive index, R ⁷ and R ⁸ are preferably hydrogen atoms or C1-4 alkyl groups independently of each other, and hydrogen is preferable. Atoms or methyl groups are more preferred.

Examples of the substituent of R ⁹ in the formula (3) include organic residues such as a hydrocarbon group, and examples thereof include a hydrocarbon group of C1-20 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 (preferably a C1-10 alkyl group, more preferably a C1-6 alkyl) such as a methyl group, an ethyl group, an n-propyl group and an isopropyl 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. Examples thereof include a group (preferably a C4-12 cycloalkyl group, more preferably a C5-8 cycloalkyl group) and the like. Examples of the aromatic hydrocarbon group include a C6-20 aryl group (preferably a C6-14 aryl group, more preferably a C6-10) such as a phenyl group, a trill group, a xsilyl group, a naphthyl group and a biphenyl 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 a halogen. Among these, R ⁹ may be an alkyl group, a cycloalkyl group, an aryl group, or an aralkyl group because it is easy to obtain a copolymer (P) having excellent heat resistance and a small compound refractive index. Preferably, a methyl group, a cyclohexyl group, a phenyl group, or a trill 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), for example, by acid anhydrideizing two carboxylic acid groups of units derived from adjacent (meth) acrylic monomers.

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

In the ring structure of the formula (3), when X ² has a glutarimide structure in which a nitrogen atom is used, R ⁷ is easy to obtain a copolymer (P) having excellent heat resistance and a small double refractive index. And R ⁸ are each independently a hydrogen atom or a methyl group, R ⁹ is more preferably a methyl group, a cyclohexyl group, a phenyl group, or a trill group, and R ⁷ and R ⁸ are independent hydrogens, respectively. It is particularly preferably an atomic or methyl group and R ⁹ is a cyclohexyl or phenyl group.

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

Among the ring structures described above, the polymer chain (B) is provided with good surface hardness, solvent resistance, adhesiveness, barrier properties, and optical properties to the resin composition containing the copolymer (P). The ring structure unit of the above is preferably a lactone ring structure and / or a succinimide structure (a structure derived from a maleimide monomer), and more preferably a lactone ring structure.

The content ratio of the ring structure unit of the main chain in the polymer chain (B) is not particularly limited, but the content ratio of the ring structure unit in the polymer chain (B) is preferably 3% by mass or more, more preferably 4% by mass or more. 5, 5% by mass or more is further preferable, 50% by mass or less is preferable, 45% by mass or less is more preferable, and 40% by mass or less is further preferable. By adjusting the content ratio of the ring structure unit of the main chain in this way, both heat resistance and mechanical strength can be imparted to the resin composition containing the copolymer (P) in a well-balanced manner. When high heat resistance and mechanical strength are imparted to the resin composition, the content ratio of the structural unit in the polymer chain (B) is preferably 10% by mass or more, more preferably 15% by mass or more. It is preferably 20% by mass or more, and more preferably 20% by mass or more. The content ratio of the ring structure unit described here means the content ratio of the unit having a ring structure contained in the main chain of the polymer chain (B), and is represented by, for example, the above formulas (1) to (3). It means the content ratio of the structure.

The polymer chain (B) may further have a unit derived from a vinyl monomer 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 is, for example, a vinyl ester such as vinyl acetate or vinyl propionate; styrene, Aromatic vinyl compounds such as vinyltoluene, methoxystyrene, α-methylstyrene and 2-vinylpyridine; vinylsilanes such as vinyltrimethoxysilane and γ- (meth) acryloyloxypropylmethoxysilane can be mentioned. For example, if the polymer chain (B) has a unit derived from an aromatic vinyl monomer, it becomes easy to adjust the refractive index and the retardation characteristic of the copolymer (P). For details of the aromatic vinyl monomer, refer to the description of the aromatic vinyl monomer of the polymer chain (A). When the polymer chain (B) is formed from two or more kinds of monomer components, the polymer chain (B) is preferably a random copolymer.

The unit derived from the vinyl monomer copolymerizable with the (meth) acrylic monomer is, for example, 0.1 part by mass or more, preferably 0.5 part by mass or more in 100 parts by mass of the polymer chain (B). It is more preferably 1 part by mass or more, for example, 30 parts by mass or less, preferably 20 parts by mass or less, and more preferably 10 parts by mass or less.

The copolymer (P) is preferably a graft copolymer in which the polymer chain (B) is grafted on the polymer chain (A). According to the glossary of basic terms of polymer science by the International Association of Pure Applied Chemistry (IUPAC) Polymer Naming Methods Committee, a graft polymer is "bonded to the main chain as a side chain in a certain polymer". When there is 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 called 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, refer to the 6th edition of the Chemical Society of Japan, Handbook of Chemistry (Applied Chemistry).

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

2. 2. Method for producing resin (S) (method for producing copolymer (P))
As described above, the resin (S) preferably contains a copolymer (P), which is a polymer block (a1) having units derived from diene and / or olefin and aromatic vinyl. In the presence of a polymer (P1) having a polymer block (a2) having a unit derived from a monomer (hereinafter, may be referred to as "raw material copolymer (P1)"), a (meth) acrylic simple substance. It can be produced by polymerizing a monomer component containing a weight (hereinafter, may be referred to as "raw material (meth) acrylic monomer"). The raw material copolymer (P1) corresponds to the polymer chain (A), and the polymer of the raw material (meth) acrylic monomer constitutes the polymer chain (B). Hereinafter, a method for producing a copolymer (P) containing all of the polymer block (a1), the polymer block (a2), and the polymer chain (B) will be described. Even when the resin (S) is a (co) polymer that does not contain the polymer block (a2) and / or the polymer chain (B), it can be produced with reference to the production method described below.

2.1 Production raw material, reagent agent The production method of the raw material copolymer (P1) is not particularly limited, and for example, the monomer components constituting the polymer block (a1) are polymerized to form the polymer block (a1). After that, it can be obtained by polymerizing the monomer components constituting the polymer block (a2) in the presence of the polymer block (a1). The raw material copolymer (P1) may be hydrogenated. Further, one kind or a combination of two or more kinds may be used. When two or more kinds are combined, it becomes easy to adjust the average molecular weight and the double bond amount as the resin composition.

The amount of the olefinic double bond in the raw material copolymer (P1) is preferably 0.2 mmol / g or more and 2.0 mmol / g or less. By using the raw material copolymer (P1) having an olefinic double bond amount of 0.2 mmol / g or more, it becomes easy to obtain a highly transparent copolymer (P). On the other hand, by using the raw material copolymer (P1) having an olefinic double bond amount of 2.0 mmol / g or less, it becomes easy to obtain a copolymer (P) in which less gelled product is generated. The amount of the olefinic double bond in the raw material copolymer (P1) is more preferably 0.4 mmol / g or more, further preferably 0.6 mmol / g or more, and further preferably 1.5 mmol / g or less. 2 mmol / g or less is more preferable, and 1.0 mmol / g or less is particularly preferable. The raw material copolymer (P1) may contain a plurality of resins having different amounts of olefinic double bonds, and even if the amount of olefinic double bonds of some of the resins exceeds 2.0 mmol / g. However, it is preferable that the amount of the olefinic double bond in the whole raw material copolymer (P1) is 2.0 mmol / g or less. The amount of olefinic double bond in the raw material copolymer (P1) can be determined by the iodine titration method.

As the raw material (meth) acrylic monomer, the (meth) acrylic monomer described in the polymer chain (B) can be appropriately used. Further, a vinyl monomer copolymerizable with the (meth) acrylic monomer may be present together with the raw material (meth) acrylic monomer, and these may be copolymerized. Further, a component (monomer for forming a ring structure) necessary for forming a ring structure in the main chain of the polymer chain (B), for example, a protonic hydrogen atom-containing group for forming a lactone ring structure or a lactam ring structure. (Meta) acrylic monomer A and (meth) acrylic monomer B, a monomer having a polymerizable double bond in the ring structure (maleic anhydride for forming a maleic anhydride structure, At least one selected from maleic anhydride (such as maleimide for forming a succinimide structure) and (meth) acrylic acid for forming a maleic anhydride structure or a glutarimide structure can be used as the raw material (meth) acrylic monomer or as the raw material (meth) acrylic monomer. It can also be used as a copolymerization component of a raw material (meth) acrylic monomer.

The amount of the raw material copolymer (P1) used in the polymerization is the same as that of the raw material copolymer (P1) and the monomer component (raw material (meth) acrylic monomer, raw material (meth) acrylic monomer). 1 part by mass or more is preferable, 3 parts by mass or more is more preferable, and 5 parts by mass or more is further preferable, 7 by mass, based on 100 parts by mass in total of the polymerizable vinyl monomer, the ring structure forming monomer, etc. More preferably, by mass or more, 9 parts by mass or more, particularly preferably 50 parts by mass or less, more preferably 40 parts by mass or less, further preferably 30 parts by mass or less, and particularly preferably 20 parts by mass or less. The amount of the monomer component used is preferably 50 parts by mass or more, more preferably 60 parts by mass or more, and 70 parts by mass or more with respect to 100 parts by mass of the total of the raw material copolymer (P1) and the monomer component. More preferably, 80 parts by mass or more is particularly preferable, 99 parts by mass or less is preferable, 97 parts by mass or less is more preferable, 95 parts by mass or less is further preferable, and 93 parts by mass or less is even more preferable.

Examples of the radical polymerization initiator include 2,2'-azobisisobutyronitrile, 2,2'-azobis (2-amidinopropane) dihydrochloride, and dimethyl-2,2'-azobis (2-). Methylpropionate), azo compounds such as 4,4'-azobis (4-cyanopentanoic acid); persulfates such as potassium persulfate; cumenehydroperoxide, diisopropylbenzenehydroperoxide, di-t-butylper Oxide, lauroyl peroxide, benzoyl peroxide, t-butylperoxyisopropyl carbonate (TBIC), t-amylperoxy-2-ethylhexanoate, t-amylperoxyoctate, t-amylperoxyisononanoate (TAIN), organic peroxides such as t-amylperoxyisopropyl carbonate and t-amylperoxy2-ethylhexyl carbonate can be used. Only one of these may be used, or two or more thereof may be used in combination. Among these, organic peroxides are preferable. Organic peroxides are particularly useful when the raw material copolymer (P1) is a hydrogenator. According to the organic peroxide, hydrogen having high activity such as vinyl position and allyl position of the double bond (olefinic double bond) possessed by the unit derived from olefin can be extracted to generate a radical at the site, and the polymer chain (B) can be generated. ) Is added and polymerized. The amount of the radical polymerization initiator used is preferably 0.01 to 1 part by mass with respect to 100 parts by mass of the monomer component, for example.

The polymerization can be carried out by using known polymerization methods such as a bulk polymerization method, a solution polymerization method, an emulsion polymerization method and a suspension polymerization method, but it is preferable to use a solution polymerization method. If the solution polymerization method is used, it is possible to suppress the mixing of minute foreign substances into the copolymer (P), and it becomes easy to suitably apply the copolymer (P) to optical material applications and the like.

The solvent used for solution polymerization can be appropriately selected depending on the composition of the monomer component, and an organic solvent used in a normal 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 and ethylene glycol dimethyl ether. , Ethers such as diethylene glycol dimethyl ether and anisole; esters such as ethyl acetate, butyl acetate, propylene glycol monomethyl ether acetate and 3-methoxybutyl acetate; cellosolves such as methyl cellosolve, ethyl cellosolve and butyl cellosolve; methanol, ethanol, isopropanol, Alcohols such as n-butanol; nitriles such as acetonitrile, propionitrile, butyronitrile, benzonitrile; chloroform; dimethyl sulfoxide and the like can be mentioned. Only one of these solvents may be used, or two or more of these solvents may be used in combination.

2.2 Addition procedure As a method for producing the resin composition used in the present invention, a radical polymerization reaction is carried out by coexisting the raw material copolymer (P1), the raw material (meth) acrylic monomer and a radical polymerization initiator. It is preferable to carry out a step of initiating the above step and a step of adding a radical polymerization initiator to the reaction solution after the start of the radical polymerization reaction. By additionally adding a radical polymerization initiator after the start of the radical polymerization reaction, the composition distribution of the polymer chain (B) can be reduced, and the reaction rate between the raw material copolymer (P1) and the (meth) acrylic monomer can be reduced. Can be improved, the aggregation phenomenon of the obtained copolymer (P) can be reduced, and the decrease in transparency of the resin composition containing the copolymer (P) under heating conditions can be prevented. Hereinafter, the mixture of the raw material copolymer (P1), the raw material (meth) acrylic monomer, and the radical polymerization initiator until the radical polymerization reaction starts is referred to as an “initial mixture”, and after the radical polymerization reaction starts. The reaction mixture (reaction solution) may be referred to as "reaction continuation solution".

The procedure for preparing the initial mixture is not particularly limited, and the raw material (meth) acrylic monomer and the radical polymerization initiator may be added to the raw material copolymer (P1), and the raw material copolymer (P1) and the raw material may be added. A radical polymerization initiator may be added to the mixture with the (meth) acrylic monomer. Further, the temperature control until the start of radical polymerization can be appropriately set. For example, after raising the temperature of the mixture of the raw material copolymer (P1) and the raw material (meth) acrylic monomer to a temperature at which polymerization can be started, the said. A radical polymerization initiator may be added to the mixture to initiate a radical polymerization reaction.

The addition of the radical polymerization initiator to the reaction solution (reaction continuation solution) after the radical polymerization reaction has started may be carried out continuously without interruption from the addition of the radical polymerization initiator for preparing the initial mixture. However, it is preferable to add the radical polymerization initiator for the preparation of the initial mixture, stop the addition once, and restart the addition of the radical polymerization initiator after the radical polymerization reaction starts. By temporarily stopping the addition, it is possible to re-add after confirming the start of the radical polymerization reaction, and the radical reaction can be safely carried out. The start of the radical polymerization reaction can be confirmed by confirming the components by sampling or the like, or by changing the liquid properties or the liquid temperature.

The addition of the radical polymerization initiator to the reaction continuation solution may be either partial addition or dropping (including continuous dropping). Further, the number of additions at the time of partial addition is not particularly limited as long as it is added twice or more, and each addition may be carried out by dropping. In order to improve the conversion rate of the monomer component, a radical polymerization initiator is preferably added dropwise, more preferably continuously. The dropping rate is, for example, about 0.1 to 1.0 parts by mass / min, preferably 0.1 to 0.8 parts by mass, when the total amount of the radical polymerization initiator used by the end of the reaction is 100 parts by mass. It is about a part / minute. The completion of the reaction can be confirmed by measuring the conversion rate, and it is assumed that the conversion rate of all the monomers reaches 85% or more.

The amount of the radical polymerization initiator added to the reaction continuation solution is, for example, 30 to 500 parts by mass, preferably 100 to 450 parts by mass with respect to 100 parts by mass of the radical polymerization initiator added to the initial mixture. It is more preferably 150 to 350 parts by mass.

The raw material copolymer (P1) may be added to the reaction continuation solution (divided addition, dropping, etc.), but it is preferable not to add it. When it is not added, the reaction rate between the raw material copolymer (P1) and the (meth) acrylic monomer can be increased. The amount of the raw material copolymer (P1) added to the reaction continuation solution is, for example, 0 to 100 parts by mass, preferably 0 to 100 parts by mass, based on 100 parts by mass of the raw material copolymer (P1) added to the initial mixture. Is 0 to 50 parts by mass, more preferably 0 parts by mass.

The raw material (meth) acrylic monomer may or may not be added to the reaction continuation solution (divided addition, dropping, etc.). Whether or not it is added to the reaction continuation solution can be determined by comparing the reactivity with the copolymerization component. When the copolymerization component is an aromatic vinyl monomer, it is better to reduce the amount of the reaction continuation solution of the raw material (meth) acrylic monomer (not particularly added) to reduce the amount of the raw material (meth) acrylic monomer. Conversion rate can be increased. In addition, the composition distribution of the polymer chain (B) when copolymerizing the aromatic vinyl monomer can be reduced, the dispersion stability of the copolymer (P) can be improved, and the transparency can be reduced under heating conditions. It can be prevented more. When the copolymerization component is an aromatic vinyl monomer, the amount of the raw material (meth) acrylic monomer added to the reaction continuation solution is 100 as the amount of the raw material (meth) acrylic monomer added to the initial mixture. With respect to the mass part, for example, it is 0 to 50 parts by mass, preferably 0 to 30 parts by mass, and more preferably 0 to 10 parts by mass.

In this polymerization reaction, the above-mentioned (meth) acrylic monomer A having a protonic hydrogen atom-containing group, the (meth) acrylic monomer B, and the monomer having a polymerizable double bond in the ring structure ( It is also possible to polymerize a ring structure forming monomer such as maleic anhydride (maleimide, maleimide, etc.) and (meth) acrylic acid. These ring structure forming monomers may be added to the initial mixture, or may be added to the reaction continuation solution (divided addition, dropping, etc.). The ratio of the amount added to the initial mixture to the amount added to the reaction continuation solution can be determined by comparing the reactivity with the copolymerization component. For example, when the copolymerization component is an aromatic vinyl monomer and the amount used is 15 parts by mass or less out of 100 parts by mass of the total monomer, the ring structure forming monomer is added to the initial mixture and the reaction is continued. It is preferable not to add it to the liquid or to reduce the amount added. When the copolymerization component is an aromatic vinyl monomer and the amount used exceeds 15 parts by mass in 100 parts by mass of the total monomer, it is preferable to add the ring-forming component to the initial mixture and the reaction continuation solution. .. By adjusting the ratio of the amount added to the initial mixture to the amount added to the reaction continuation solution in this way, the conversion rate of the monomer for forming the ring structure can be increased, or as described above, the (meth) acrylic single amount. The composition distribution of the polymer chain (B) when the body and the aromatic vinyl monomer are reacted can be reduced, the dispersion stability of the (meth) acrylic block copolymer (P) can be enhanced, and the heating conditions can be improved. It is possible to further prevent the decrease in transparency in. The amount of the ring structure-forming monomer added to the initial mixture when the aromatic vinyl monomer is reacted is, for example, 20 parts by mass with respect to 100 parts by mass of the total amount of the ring structure-forming monomer added. The above is preferably 30 parts by mass or more, more preferably 40 parts by mass or more, and most preferably 100 parts by mass.

In this polymerization reaction, a vinyl monomer (however, it does not contain a monomer for forming a ring structure) may be copolymerized with the raw material (meth) acrylic monomer. The vinyl monomer may be added to the initial mixture or may be added to the reaction continuation solution (divided addition, dropping, etc.). The ratio of the amount added to the initial mixture to the amount added to the reaction continuation solution can be determined by comparing the reactivity of the raw material (meth) acrylic monomer and the vinyl monomer. When the vinyl monomer is an aromatic vinyl monomer, it is preferable to add it to the reaction continuation solution while not adding it to the initial mixture or reducing the amount of the vinyl monomer added. By increasing the amount added in the reaction continuation solution, the composition distribution of the polymer chain (B) at the time of copolymerizing the aromatic vinyl monomer can be reduced, and the dispersion stability of the copolymer (P) can be improved. It is possible to prevent a decrease in transparency under heating conditions. The amount of the vinyl monomer added to the reaction continuation solution is, for example, 70 parts by mass or more, preferably 80 parts by mass or more, more preferably 80 parts by mass, based on 100 parts by mass of the total amount of the vinyl monomer added. It is 90 parts by mass or more, and most preferably 100 parts by mass.

In the polymerization reaction, a chain transfer agent may be added to at least one of the initial mixture and the reaction continuation solution, preferably the initial mixture. The molecular weight distribution can be reduced by using a chain transfer agent. Chain transfer agents include butanethiol, octanethiol, octadecanethiol, dodecanethiol, cyclohexyl mercaptan, thiophenol, octyl thioglycolate, octyl 2-mercaptopropionate, octyl 3-mercaptopropionate, 2-ethylhexyl ester of mercaptopropionate. , Octanoic acid 2-mercaptoethyl ester, 1,8-dimercapto-3,6-dioxaoctane, n-dodecyl mercaptan, ethylene glycol bisthioglycolate and other mercaptans; carbon tetrachloride, carbon tetrabromide, methylene chloride, Halogen compounds such as bromoform and bromotrichloroethane; α-methylstyrene dimer and the like can be mentioned. The amount of the chain transfer agent used is preferably 0.01 to 3 parts by mass with respect to 100 parts by mass of all the monomer components used in the initial mixture and the reaction continuation solution, for example.

2.3 Reaction conditions In the initial mixture, the raw material copolymer (P1) and the monomer (raw material (meth) acrylic monomer, ring structure forming monomer, vinyl monomer, etc., especially the raw material (meth) acrylic The system monomer (monomer for forming a ring structure) may be dissolved or dispersed in the solvent, and the total concentration of the raw material copolymer (P1) and the monomer is, for example, 10 to 80% by mass. It is preferably 30 to 70% by mass, more preferably 40 to 60% by mass.
The radical polymerization initiator added to the reaction continuation solution may be dissolved or dispersed in the solvent, and the concentration of the radical polymerization initiator added to the reaction continuation solution is, for example, 1 to 50% by mass, preferably 2 to 2 to. It is 30% by mass, more preferably 3 to 25% by mass.
The monomer (raw material (meth) acrylic monomer, ring structure forming monomer, vinyl monomer, etc., especially aromatic vinyl monomer) added to the reaction continuation solution is dissolved or dispersed in the solvent. If it is a liquid, it may be added as it is without being mixed with a solvent.
The radical polymerization initiator and the monomer to be added to the reaction continuation solution may be separately added to the reaction continuation solution, or both may be mixed first and then added to the reaction continuation solution.

The reaction is preferably carried out in an atmosphere of an inert gas such as nitrogen gas or in an air flow. The reaction temperature is, for example, 50 to 200 ° C, preferably 70 to 150 ° C, and more preferably 90 to 120 ° C. The reaction time is preferably, for example, 1 hour to 20 hours. Further, a step of aging after the addition of the radical polymerization initiator added to the initial mixture or after the addition of the radical polymerization initiator to the reaction continuation solution may be included, and the degree of progress of the polymerization reaction and the degree of formation of the gelled product may be determined. You can make appropriate adjustments while looking at it. Further, the aging temperature may be the same as the polymerization temperature at the time of adding the radical polymerization initiator, or may be maintained at a temperature higher than the polymerization temperature at the time of addition for aging.

The polymerization conversion rate in the polymerization reaction is 85% or more, that is, it can be copolymerized with each monomer (raw material (meth) acrylic monomer, raw material (meth) acrylic monomer) in the polymerization reaction. The conversion rate of the vinyl monomer, the monomer for forming the ring structure, etc.) is 85% or more. By adjusting the polymerization conversion rate, the amount of olefinic double bond in the resin composition can be adjusted. If the conversion rate of each monomer is lower than 85%, a new facility for recovering the monomer is required, or the residual monomer causes an undesired reaction in the next step, etc., and gel is generated. It can significantly reduce productivity. The conversion rate of each monomer in the polymerization reaction is preferably as follows.
Conversion rate of raw material (meth) acrylic monomer: preferably 90% or more Conversion rate of vinyl monomer (excluding ring structure forming monomer) copolymerizable with raw material (meth) acrylic monomer : Preferably 90% or more, more preferably 95% or more Conversion rate of ring structure forming monomer: preferably 90% or more, more preferably 94% or more.

2.4 Volatilization step When the ring structure is not introduced into the polymer chain (B), a post-treatment step including a volatilization step is performed after the above polymerization step, if necessary. Further, a monomer having a polymerizable double bond in the ring structure (preferably at least one selected from maleic anhydride and maleimide) is used as the ring structure forming monomer to form a ring structure in the polymer chain (B). No special cyclization step is required even in the case of introducing the above, and after the polymerization step, a post-treatment step including a devolatile step is performed if necessary.

In the devolatile step, the polymerization reaction solution containing the polymerization solvent is heated and / or depressurized to remove the solvent. In the devolatilization step, an autoclave, a kettle-type reactor, a device including a heat exchanger and a devolatilization tank, an extruder with a vent, and the like can be used, and a dryer may be used.

When an extruder with a vent is used, it is preferable that the extruder has a cylinder and a screw provided in the cylinder, and is provided with heating means. 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 section with respect to the transfer direction in the extruder, and may be provided on the upstream side of the raw material feeding section.

Devolatileization proceeds in the process of transferring the polymerization reaction product supplied into the extruder from the upstream side to the downstream side of the extruder while kneading with a screw, and the copolymer (P) is discharged from the downstream side of the extruder. To. It is preferable that a die is provided on the downstream side of the extruder, and the copolymer (P) can be formed into a predetermined shape (film shape or rod shape) by discharging the copolymer (P) from the die. For example, pellets can be produced by finely cutting a copolymer formed into a rod shape.

2.5 Cyclization step (ring structure forming step) and volatilization step On the other hand, (meth) acrylic monomer A, (meth) acrylic monomer B, (meth) acrylic having a protonic hydrogen atom-containing group. When the polymer chain (B) is copolymerized using an acid or the like as a ring structure forming monomer, the polymer chain (B) is formed by performing a cyclization reaction (ring structure forming step) after the copolymerization reaction. A ring structure can be introduced into the main chain of. Specifically, a condensation reaction between the reactive groups (ester group, -COOH group, -OH group, -NH ₂ group) of the adjacent monomer units of the polymer chain (B) formed in the polymerization step. To form a ring structure in the main chain of the polymer chain (B). The cyclization condensation reaction includes an esterification reaction, an amidation reaction, an acid anhydrideization reaction, an imidization reaction and the like. For example, an anhydrous glutaric acid structure can be formed by acid anhydrideizing 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 protonic hydrogen atom-containing group such as a hydroxy group or an amino group, one of the (meth) acrylic units has a protonic hydrogen atom-containing group and the other (meth) acrylic unit. A lactone ring structure or a lactam ring structure can be formed by condensing with a carboxylic acid group of a meta) acrylic unit.

In the ring structure forming step, the condensation reaction between the reactive groups of adjacent monomer 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. Acids, bases 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 a cyclization catalyst, the cyclization condensation reaction can be efficiently performed and the coloring of the obtained copolymer (P) can be reduced.

Organic phosphorus compounds that can be used as cyclization catalysts include, for example, alkyl (aryl) subphosphonic acid and monoesters or diesters thereof; dialkyl (aryl) phosphinic acid and esters thereof; alkyl (aryl) phosphonic acid and these. Monoesters or diesters; alkyl (aryl) subphosphinic acid and their esters; phosphoric acid monoesters, diesters or triesters; 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, Di-Phosphate Phosphate monoesters such as isostearyl, diphenyl phosphate, trimethyl phosphate, triethyl phosphate, triisodecyl phosphate, trilauryl phosphate, tristearyl phosphate, triisostearyl phosphate, triphenyl phosphate; Examples thereof include mono-, di- or tri-alkyl (aryl) phosphine; alkyl (aryl) halogen phosphine; mono-, di- or tri-alkyl (aryl) phosphine; tetraalkyl (aryl) phosphonium halide and the like. Only one of these may be used, or two or more thereof may be used in combination. 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 0.001 to 1 part by mass with respect to 100 parts by mass of the copolymer obtained in the polymerization step, for example.

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 progress of the cyclization condensation reaction, and is preferably carried out for, for example, 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, the polymerization solvent may be devolatile and then heated, or both of them may be combined. Examples of the reactor used for the cyclization condensation reaction include an autoclave, a kettle-type reactor, a device consisting of a heat exchanger and a devolatilization tank, an extruder with a vent, and the like.

In the ring structure forming step, it is preferable to carry out volatilization. Volatilization can be performed by reducing the pressure inside the reactor with a vacuum pump or the like. It can also be devolatile by heating in an autoclave and then vacuum drying. By devolatileization, the polymerization solvent used in the polymerization step and brought into the ring structure forming step, the alcohol produced by the cyclization condensation reaction, etc. are removed, 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 cyclization condensation reaction are removed, the reaction equilibrium is inclined toward the production side, which is advantageous.

When the cyclization condensation reaction is carried out while devolatile, it is preferable to carry out the cyclization condensation reaction under reduced pressure from the viewpoint of efficient devolatileation. The reduced pressure in the cyclization condensation reaction is, for example, preferably 90 kPa or less, more preferably 80 kPa or less, still more preferably 70 kPa or less as an absolute pressure. On the other hand, the absolute pressure at the time of depressurization 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 become an excessive specification and the equipment cost is kept low. When the cyclization condensation reaction is carried out without devolatile, the cyclization condensation reaction may be carried out under normal pressure or pressure.

When cyclizing while devolatile, it is preferable to use an extruder with a vent. The structure of the extruder with a vent is the same as that of the extruder with a vent used in the above-mentioned devolatilization step. The cyclization condensation reaction proceeds in the process of transferring the polymerization reaction product supplied into the extruder from the upstream side to the downstream side of the extruder while kneading with a screw, and the copolymer (P) is released from the downstream side of the extruder. It is discharged. It is preferable that a die is provided on the downstream side of the extruder, and the copolymer (P) can be formed into a predetermined shape (film shape or rod shape) by discharging the copolymer (P) from the die. For example, pellets can be produced by finely cutting the copolymer (P) formed into a rod shape.

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 deactivating agent after or during the cyclization condensation reaction. For example, when a resin composition containing a 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. As a result, unwanted foaming may occur. However, such foaming can be prevented by adding a deactivating agent after or during the cyclization condensation reaction.

As the deactivating agent, a substance capable of neutralizing the cyclization catalyst is preferably used. For example, when the cyclization catalyst is an acidic substance, a basic substance can be used as the deactivating agent, and conversely, when the cyclization catalyst is a basic substance, an acidic substance can be used as the deactivating agent. .. As described 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 deactivating agent. The basic substance is not particularly limited as long as it can have a function of stopping the cyclization condensation reaction, and for example, a metal carboxylate, a metal complex, a metal oxide, or the like is used. On the contrary, when a basic substance is used as the cyclization catalyst, an acidic substance that can be used for the cyclization catalyst described above can be used as the deactivating agent.

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

3. 3. Resin composition As described above, the resin composition used in the present invention preferably contains the resin (S), and the resin (S) more preferably contains the above-mentioned copolymer (P). Further, the resin composition used in the present invention preferably contains a resin (R) having a negative orientation birefringence as a resin component (matrix resin). The resin (R) preferably contains a (meth) acrylic polymer (Q), and the (meth) acrylic polymer (Q) is excellent in compatibility with the copolymer (P). preferable. By containing the (meth) acrylic polymer (Q), it becomes easy to enhance the transparency and heat resistance of the film.

The (meth) acrylic polymer (Q) may have a unit derived from the (meth) acrylic monomer described in the above polymer chain (B), and is preferably the above polymer chain (B). It has a unit derived from the (meth) acrylic acid ester described in). The (meth) acrylic polymer (Q) may have a unit derived from the other unsaturated monomer described in the polymer chain (B) above. The structural unit of the (meth) acrylic polymer (Q) is preferably the same as the structural unit of the polymer chain (B) from the viewpoint of enhancing the compatibility with the copolymer (P).

The (meth) acrylic polymer (Q) preferably has a ring structure, and more preferably has a ring structure in the main chain. This makes it possible to improve the transparency and heat resistance of the film. The ring structure of the main chain of the (meth) acrylic polymer (Q) includes a lactone ring structure, a lactam ring structure, a cyclic imide structure (for example, a succinimide structure, a glutarimide structure, etc.), and a cyclic anhydride structure (for example, anhydrous). Succinic acid structure, glutaric anhydride structure, etc.) are preferably mentioned, and for details of these ring structures, the above description of 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) has the same (meth) acrylic unit as the (meth) acrylic unit of the polymer chain (B) of the copolymer (P), and the ring of the polymer chain (B). It is preferable to have the same ring structural unit as the structural unit. As a result, the compatibility between the (meth) acrylic polymer (Q) and the copolymer (P) is enhanced, and it becomes easy to enhance the transparency and heat resistance of the film.

In such a (meth) acrylic polymer (Q), when the copolymer (P) is polymerized and generated, the polymer chain (B) forming monomer is polymerized separately from the raw material copolymer (P1). By doing so, it is convenient to carry out polymerization together in the same polymerization reaction system. In the method for producing the copolymer (P) described above, not only the copolymer (P) but also the (meth) acrylic polymer (Q) corresponding to the polymer chain (B) of the copolymer (P) is simultaneously produced. A resin composition containing the copolymer (P) and the (meth) acrylic polymer (Q) by forming the polymer and not separating the copolymer (P) and the (meth) acrylic polymer (Q) at this time. You can get things. The resin composition thus obtained, which contains substantially only the (meth) acrylic copolymer (Q) and the copolymer (P) as a polymer, is hereinafter referred to as a "two-component mixture". There is. In order to include a polymer other than the (meth) acrylic polymer (Q) in the resin composition, the copolymer (P) may be isolated or not isolated, and another polymer may be blended. ..

The content ratio of the copolymer (P) in the resin composition is preferably 1% by mass or more, more preferably 3% by mass or more, further preferably 5% by mass or more, still more preferably 15% by mass or more, thereby. It becomes easy to increase the mechanical strength of the resin molded product. 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), and the copolymer in the resin composition ( The content ratio of P) may be 90% by mass or less, 70% by mass or less, 50% by mass or less, 40% by mass or less, or 30% by mass or less.

The content ratio of the polymer chain (A) of the copolymer (P) in the resin composition is preferably 1% by mass or more, more preferably 3% by mass or more, further preferably 5% by mass or more, and 50% by mass or less. Is preferable, 40% by mass or less is more preferable, and 30% by mass or less is further preferable. When the content ratio 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 resin molded product. When the content ratio of the polymer chain (A) in the resin composition is 50% by mass or less, the transparency and heat resistance of the resin molded product can be easily improved. Further, when the content ratio of the polymer chain (A) in the resin composition is 50% by mass or less, the positive birefringence derived from the resin (R) is canceled out in the film on which the phase-separated structure is formed. The morphological birefringence of can be expressed.

The content ratio of the ring structure unit in the solid content of 100% by mass of the resin composition is not particularly limited, but is preferably 3% by mass or more, more preferably 4% by mass or more, still more preferably 5% by mass or more, and 50% by mass. The following is preferable, 45% by mass or less is more preferable, and 40% by mass or less is further preferable. By adjusting the content ratio of the ring structure unit within the above range, it becomes easy to improve both the heat resistance and the mechanical strength of the resin composition in a well-balanced manner. The content ratio of the ring structure unit described here is the content of the unit having a ring structure contained in the main chain of the polymer chain (B) of the copolymer (P) and the (meth) acrylic polymer (meth) acrylic polymer (meth). It means the ring structure contained in the main chain of Q), and means, for example, the content ratio of the structures represented by the above formulas (1) to (3).

The content ratio of the (meth) acrylic polymer (Q) in the resin composition is preferably 1% by mass or more, more preferably 10% by mass or more, further preferably 20% by mass or more, still more preferably 30% by mass or more. It is 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. The total content of the (meth) acrylic polymer (Q) and the polymer chain (B) in the resin composition is preferably 30% by mass or more, more preferably 50% by mass or more, and further preferably 70% by mass or more. It is preferably 99% by mass or less, more preferably 95% by mass or less, still more preferably 93% by mass or less.

The total content of the copolymer (P) and the (meth) acrylic polymer (Q) in the resin composition is preferably 50% by mass or more, more preferably 70% by mass or more, still more preferably 80% by mass or more. , 90% by mass or more is even more preferable. The upper limit of the content ratio of the copolymer (P) and the (meth) acrylic polymer (Q) in the film is not particularly limited, and the film is substantially the copolymer (P) and the (meth) acrylic polymer. It may be composed of only (Q).

The resin composition used in the present invention may contain a polymer other than the (meth) acrylic polymer (Q) described above, and examples of such a polymer include polyethylene and polypropylene. Olefin-based polymers such as ethylene-propylene polymer and poly (4-methyl-1-pentene); halogen-containing polymers such as vinyl chloride and chlorinated vinyl resin; polystyrene, styrene-methyl methacrylate copolymer, styrene -Sterite polymers such as acrylonitrile copolymers and acrylonitrile-butadiene-styrene copolymers; polyesters such as polyethylene terephthalate, polybutylene terephthalate and polyethylene naphthalate; polyamides such as nylon 6, nylon 66 and nylon 610; polyacetal; polycarbonate Polyphenylene oxide; Polyphenylene sulfide; Polyether ether ketone; Polysulfone; Polyether sulfone; Polyoxypendylene; Polyamideimide; Cycloolefin polymer; Cellulous derivative; Polybutadiene-based rubber, ABS resin containing (meth) acrylic rubber A rubbery polymer such as ASA resin; and the like.

The weight average molecular weight of the resin composition (preferably a two-component mixture) is preferably 2,000 or more, more preferably 5,000 or more, still more preferably 30,000 or more, still more preferably 50,000 or more. 10,000 or more is particularly preferable, 600,000 or less is preferable, 400,000 or less is more preferable, 300,000 or less is further preferable, 200,000 or less is further preferable, and 150,000 or less is particularly preferable. By setting the weight average molecular weight of the resin composition in such a range, the moldability of the copolymer (P) is improved.

The molecular weight distribution (= weight average molecular weight / number average molecular weight) of the resin composition (preferably a two-component mixture) is, for example, 1.5 or more, preferably 1.8 or more, more preferably 2.0 or more. For example, it is 5.0 or less, preferably 4.0 or less, and more preferably 3.0 or less.

The weight average molecular weight of the resin composition (preferably a two-component mixture) is preferably 1.1 times or more, more preferably 1.2 times or more, and further preferably 1.3 times or more the weight average molecular weight of the polymer chain (A). It is preferable, 10 times or less is preferable, 7 times or less is more preferable, and 5 times or less is further preferable. This makes it easy to impart the properties of transparency and mechanical strength to the copolymer (P) in a well-balanced manner.

The refractive index of the resin composition is preferably a value close to the refractive index of the polymer chain (A) of the copolymer (P), which makes it easy to ensure the transparency of the resin composition. Specifically, the difference between the refractive index of the resin composition and the refractive index of the polymer chain (A) of the copolymer (P) is preferably less than 0.1, more preferably 0.05 or less, and 0. 0.02 or less is more preferable.

The resin composition preferably has an insoluble content in chloroform of 10% by mass or less, more preferably 8% by mass or less, and further preferably 5% by mass or less. In this case, the amount of foreign matter contained in the resin composition is small, and for example, when a film is formed from the resin composition, a film having few surface irregularities and defects and high transparency can be easily obtained. Further, when removing foreign matter from the resin composition, the load applied to the foreign matter removing filter is reduced, and the manufacturing efficiency is improved. To determine the insoluble content of the resin composition in chloroform, add 1 g of the resin composition to 20 g of chloroform, filter this with a Teflon (registered trademark) membrane filter having a pore size of 0.5 μm, and collect the insoluble content in the membrane filter. Can be obtained by measuring.

The internal haze per 100 μm thickness of the unstretched film is preferably 2.0% or less, more preferably 1.0% or less, further preferably 0.50% or less, and 0.30. % Or less is particularly preferable, and 0.18% or less is most preferable. The lower limit of the internal haze is not particularly limited, but is, for example, 0.01% or more. The internal haze is determined by the method described in the examples.

The fracture energy (impact strength) of an unstretched film having a thickness of 160 μm is preferably 30 mJ or more, and more preferably 40 mJ or more. By setting the breaking energy to a film of 30 mJ or more, a film having high mechanical strength can be obtained. Destructive energy is determined by the method described in the examples.

The resin composition may contain various additives. Examples of the additive include ultraviolet absorbers; antioxidants such as hindered phenol-based, phosphorus-based and sulfur-based; stabilizers such as light-resistant stabilizers, weather-resistant stabilizers and heat-stabilizing agents; glass fibers, carbon fibers and the like. Reinforcing material; Near-infrared absorber; Flame-retardant agent such as tris (dibromopropyl) phosphate, triallyl phosphate, antimony oxide; Phase difference adjuster such as phase difference enhancer, phase difference reducing agent, phase difference stabilizer; Anion type, Antistatic agents containing cationic and nonionic surfactants; colorants such as inorganic pigments, organic pigments and dyes; organic fillers and inorganic fillers; resin modifiers; organic fillers and inorganic fillers; etc. .. The content ratio of each additive in the resin composition is preferably in the range of 0 to 5% by mass, more preferably 0 to 2% by mass.

The resin composition preferably has a glass transition temperature of 115 ° C. or higher, and more preferably has a glass transition temperature of 115 ° C. or higher and lower than 115 ° C., respectively. The glass transition temperature of 115 ° C. or higher is referred to as "glass transition temperature on the high temperature side", and the glass transition temperature of less than 115 ° C. is referred to as "glass transition temperature on the low temperature side". 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. Since the resin composition has a glass transition temperature on the high temperature side, the heat resistance of the resin composition is enhanced, and when the resin composition is molded into a film or the like, it does not soften even at a high temperature and the molding processability is enhanced. Can be done. 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 enhanced. The glass transition temperature on the high temperature side of the resin composition is 115 ° C. or higher, preferably 120 ° C. or higher, and from the viewpoint of improving the processability of the resin composition, it is preferably less than 300 ° C., more preferably less than 200 ° C. Less than 180 ° C. is more preferable, 150 ° C. or lower is particularly preferable, and 140 ° C. or lower is most preferable. The glass transition temperature on the low temperature side of the resin composition is preferably −100 ° C. or higher, more preferably −70 ° C. or higher, preferably lower than 50 ° C., more preferably lower than 30 ° C., further preferably lower than 10 ° C., and further preferably −20 ° C. Less than -50 ° C is particularly preferable, and less than -50 ° C is most preferable.

4. Film The resin composition can be molded into a film by molding according to a known method. The film forming method will be described later.

The thickness of the film is preferably 5 μm or more, more preferably 15 μm or more, still more preferably 20 μm or more, from the viewpoint of increasing the strength of the film. On the other hand, from the viewpoint of thinning the film, the thickness of the film is preferably 350 μm or less, more preferably 200 μm or less, further preferably 150 μm or less, and particularly preferably 60 μm or less. The thickness of the film can be measured, for example, using a Digimatic Micrometer manufactured by Mitutoyo.

The film of the present invention is preferably a uniaxial or biaxially stretched film. By using a uniaxial or biaxial stretched film, the degree of orientation birefringence can be adjusted. Since the orientation birefringence can be adjusted independently of the morphological birefringence, the phase difference of the film can be easily reduced.
Further, by using a uniaxial or biaxially stretched film, it is possible to obtain a film having high mechanical strength. Specifically, the film of the present invention has a folding resistance of 1000 times or more according to a MIT test based on JIS P 8115 (2001). On the other hand, for example, in the case of polymethylmethacrylate or a (meth) acrylic polymer having a lactone ring structure in the main chain as disclosed in JP-A-2008-191426, even if this is made into a stretched film, such a polymer is obtained. It is difficult to impart high mechanical strength, and the number of folding resistances in the MIT test is limited to several hundred times at most. The film of the present invention preferably has a folding resistance of 2000 times or more, and more preferably 3000 times or more. The folding resistance may also be 5000 times or more, 7000 times or more, or 9000 times or more. The upper limit of the number of folding resistance is not particularly limited. The number of folding resistances in the MIT test is determined by the method described in Examples.

The film of the present invention preferably has an internal haze of 1.0% or less, more preferably 0.50% or less, particularly preferably 0.30% or less, and most preferably 0.10% or less. The lower limit of the internal haze is not particularly limited, but is, for example, 0.01% or more. The internal haze is determined by the method described in the examples.

The film of the present invention preferably has an internal haze of 2.0% or less, more preferably 1.0% or less, still more preferably 0.50% or less, and 0.30% per 100 μm thickness. The following is particularly preferable, and 0.18% or less is most preferable. The lower limit of the internal haze is not particularly limited, but is, for example, 0.01% or more. The internal haze is determined by the method described in the examples.

The film of the present invention preferably has a breaking energy (impact strength) of 30 mJ or more, more preferably 40 mJ or more. By setting the breaking energy to a film of 30 mJ or more, a film having high mechanical strength can be obtained. Destructive energy is determined by the method described in the examples.

From the viewpoint of increasing heat resistance, the film of the present invention preferably has a glass transition temperature in the temperature range of 115 ° C. or higher. The glass transition temperature is preferably 120 ° C. or higher, more preferably 130 ° C. or higher. Further, from the viewpoint of improving processability at the time of film formation, the glass transition temperature is preferably less than 300 ° C, more preferably less than 200 ° C, further preferably less than 180 ° C, particularly preferably 150 ° C or lower, and particularly preferably 140 ° C or lower. Most preferred.
When the glass transition temperature described above is defined as the glass transition temperature on the high temperature side, the film of the present invention preferably has the glass transition temperature on the low temperature side in a temperature range of less than 115 ° C. If the film has such a glass transition temperature on the low temperature side, the mechanical strength and impact resistance of the film can be enhanced. The glass transition temperature on the low temperature side is preferably less than 50 ° C, more preferably less than 30 ° C, further preferably less than 10 ° C, particularly preferably less than -20 ° C, most preferably less than -50 ° C, and more preferably -100 ° C or higher. Preferably, it is more preferably −90 ° C. or higher, and even more preferably −80 ° C. or higher.

5. Film forming method As a film forming method, known methods such as a solution casting method (solution casting method), a melt extrusion method, a calendar method, and a compression molding method can be used. Among these, the solution casting method and the melt extrusion method are preferable.

Examples of the device 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 form 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. For example, uniaxial stretching such as free width uniaxial stretching and constant width uniaxial stretching; biaxial stretching such as sequential biaxial stretching and simultaneous biaxial stretching; when the film is stretched, a shrinkable film is adhered to one or both sides of the film to form a laminate. A birefringent film in which molecular groups oriented in the stretching direction and the thickness direction are mixed is formed by heat-stretching the laminate and applying a contraction force in a direction orthogonal to the stretching direction to the film. Examples thereof include stretching to obtain. Biaxial stretching is preferably used from the viewpoint of improving mechanical strength such as folding resistance of the film. 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 and a tenter type stretching machine, and examples of the small experimental stretching device include a tensile tester, a uniaxial stretching machine, a sequential biaxial stretching machine, a simultaneous biaxial stretching machine, and the like. The device can be used.

6. Optical film The film of the present invention can be suitably used as an optical film because the phase difference is very small. The optical film may be a uniaxial or biaxially stretched film or an unstretched film, but is preferably a uniaxial or biaxially stretched film, and more preferably a biaxially stretched film. When the stretched film is applied to an optical film, heat treatment (annealing) may be performed after stretching, if necessary, in order to stabilize the optical and mechanical properties of the optical film.

Examples of the optical film include an optical protective film (specifically, a protective film for a substrate of various optical disks (VD, CD, DVD, MD, LD, etc.)) and a polarizing plate included in an image display device such as a liquid crystal display. Examples thereof include a polarizing element protective film, a viewing angle compensating film, a light diffusing film, a reflective film, an antireflection film, an antiglare film, a luminance improving film, a conductive film for a touch panel, and a film for optical conversion.

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

The optical film of the present invention (for example, a polarizing element protective film, a transparent conductive film) 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 can 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, a micro LED, and the like.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited by the following examples as well as the present invention, and appropriate modifications are made to the extent that it can meet the purposes 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, unless otherwise specified, "part" represents "parts by mass" and "%" represents "% by mass".

(1) Analytical method (1-1) Weight average molecular weight (Mw) and number average molecular weight (Mn)
The weight average molecular weight and the number average molecular weight were determined by polystyrene conversion using gel permeation chromatography (GPC). The equipment and measurement conditions used for the measurement are as follows.
-Measurement system: GPC system HLC-8220 manufactured by Tosoh Corporation
-Measurement side column configuration Guard column: manufactured by Tosoh Corporation, TSKguardcolum SuperHZ-L
Separation column: Tosoh, TSKgel SuperHZM-M 2 series connection-Reference side column configuration Reference column: Tosoh, TSKgel SuperH-RC
-Development solvent: Chloroform (manufactured by Wako Pure Chemical Industries, Ltd., special grade)
-Solvent flow rate: 0.6 mL / min-Standard sample: TSK standard polystyrene (Tosoh, PS-oligomer kit)

(1-2) Glass transition temperature (Tg)
The glass transition temperature was determined according to JIS K 7121 (2012). Specifically, the sample is obtained by raising the temperature from room temperature to 200 ° C. (heating rate 20 ° C./min) in a nitrogen gas atmosphere using a differential scanning calorimeter (Thermo plus EVO DSC-8230 manufactured by Rigaku Co., Ltd.). The DSC curve was evaluated by the starting point method. Α-Alumina was used as a reference. For the glass transition temperature below 40 ° C, use a differential scanning calorimeter (DSC-3500 manufactured by Netch Co., Ltd.) to raise the temperature of the sample from -100 ° C to 60 ° C (heating rate 10 ° C / min) under a nitrogen gas atmosphere. The DSC curve obtained was evaluated by the starting point method. An empty container was used as a reference.

(1-3) Monomer conversion rate and resin composition composition The monomer conversion rate (reaction rate) and resin composition composition were determined by using gas chromatography (manufactured by Shimadzu Corporation, GC-2014) in the polymerization solution. It was determined by measuring the amount of residual monomer. The measuring device and measuring conditions for gas chromatography are as follows.
Column: Shinwa Kako, ULBON HR-1, length 50m, inner diameter 0.25mm, film thickness 0.25μm
Column temperature rise condition: After holding at 60 ° C. for 5 minutes, the temperature is raised to 235 ° C. over 35 minutes at a temperature rise rate of 5 ° C./min, and further to 315 ° C. over 3.2 minutes at a temperature rise rate of 25 ° C./min. The temperature was raised and the mixture was kept as it was for 10 minutes.
Vaporization chamber temperature: 250 ° C
Detector (FID) temperature: 320 ° C
Carrier gas: helium (250 kPa)
Total flow rate: 19.2 mL / min Column flow rate: 2.69 mL / min Split ratio: 5.0

(1-4) Destructive energy (impact strength)
The resin composition was heat-press molded at 250 ° C. to prepare a film (unstretched film) having a thickness of 160 μm. A test of dropping a ball having a mass of 0.0054 kg from a certain height was carried out 10 times on this film, and the average value of the height (breaking height) when the film was broken was obtained. Specifically, when the height was set in several steps and the balls were dropped in order from the lowest height, the height at which the film cracked was obtained, and this was repeated 10 times to crack the film. The height was calculated for 10 times, and the average value was calculated as the breaking height. Whether or not the film was broken was determined by visually confirming whether or not the film was deformed after the ball was dropped onto the film. If any deformation was seen, the film was considered to have been destroyed. The fracture energy (E) was obtained according to the following equation: fracture energy E (mJ) = mass of sphere (kg) × average value of fracture height (mm) × 9.8 (m / s ² ).

(1-5) Dispersion state (observation of sea island structure size by STEM)
The resin composition was heat-press molded at 250 ° C. to prepare a film (unstretched film) having a thickness of about 160 μm. The dispersed state (sea island structure) of this film due to phase separation of the film was observed with a scanning electron microscope (FE-SEM S-4800, manufactured by Hitachi High-Technologies Corporation). The measurement conditions are an acceleration voltage of 20 kV, an emission current of 5 μA or 10 μA, and a wattage. D. It was done at = 8 mm. The island size was calculated as the average value of the maximum lengths of 10 islands at any point.

(1-6) Folding resistance by MIT test The resin composition was heat-press molded at 250 ° C. to prepare a film (unstretched film) having a thickness of about 160 μm. The obtained unstretched film was cut into a size of 96 mm × 96 mm, and using a sequential biaxial stretching machine (X6-S manufactured by Toyo Seiki Seisakusho Co., Ltd.), the resin composition was Tg + 24 ° C. at a temperature of 240 mm / min. A stretched film having a thickness of 40 μm was obtained by sequentially biaxially stretching and cooling so that the stretching ratio was doubled in the order of the stretching speed in the vertical direction (MD direction) and the horizontal direction (TD direction). The obtained stretched film was cut into a size of 90 mm (MD direction) × 15 mm (TD direction) to form a test piece, and the temperature was 23 ° C. using a MIT folding resistance tester (BE-201 manufactured by Tester Sangyo Co., Ltd.). A load of 200 g was applied in an atmosphere of 50% relative humidity, and a MIT fold resistance test was performed based on JIS P 8115 (2001) to measure the number of fold resistance.

(1-7) Internal haze The quartz cell is filled with 1,2,3,4-tetrahydronaphthalene (tetralin), and a stretched film having a thickness of 40 μm prepared by the method described in (1-6) above is immersed therein. Then, the haze was measured using a haze meter (NDH-5000 manufactured by Nippon Denshoku Kogyo Co., Ltd.). Further, the internal haze per 100 μm thickness was calculated according to the following equation: internal haze per 100 μm thickness (%) = obtained measured value (%) × (100 μm / film thickness (μm)). The measurement was performed using three films, and the internal haze per 100 μm thickness was calculated from the average value.

(1-8) Phase difference An incident angle of a stretched film produced by the same method as described in (1-6) above using a fully automatic birefringence meter (KOBRA-WR, manufactured by Oji Measuring Instruments Co., Ltd.). Under the condition of 40 °, the in-plane phase difference Re and the thickness direction phase difference Rth with respect to the light having a wavelength of 589 nm were measured. The refractive index in the slow axis direction in the plane of the film is nx, the refractive index in the phase advance 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. The in-plane phase difference Re and the thickness direction phase difference Rth were obtained from the equations, respectively.
In-plane phase difference Re = (nx-ny) x d
Thickness direction phase difference Rth = [(nx + ny) /2-nz] × d

(1-9) 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 prepared resin composition was heat-press molded by a hot press at 250 ° C. to obtain an unstretched film (thickness 190 μm) of the polymer. Next, the produced unstretched film was cut out in a size of 20 mm × 60 mm to obtain a test piece for Cr evaluation. Next, a weight having a weight of 1 N / mm ² or less applied to the test piece at the time of stretching is selected and attached to one short side of the test piece, and then the temperature is adjusted to Tg + 20 ° C. of the polymer to be evaluated. It was housed in a constant temperature dryer (manufactured by AS ONE, DOV-450A) and left for 1 hour. When the test piece is housed in a constant temperature dryer, the other short side of the test piece is fixed by 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). It was made to be stretched. Further, when accommodating, the distance between the chuck and the weight in the test piece was set to 40 mm. 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. 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 with respect to 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. While changing the weight of the weight, Δn and σ were obtained for each load, and the slope of Δn with respect to the obtained σ was obtained by the least squares method, and this was defined as the stress optical coefficient Cr (Pa ^-1 ). When the orientation angle when measuring the in-plane phase difference Re is close to 0 ° with respect to the stretching direction (load application direction), the sign of the stress optical coefficient Cr is positive. 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 sign of the stress optical coefficient Cr becomes negative. In this case, the orientation birefringence of the polymer to be evaluated is negative. The larger the absolute value of Cr, the higher the expression of birefringence (expression of phase difference) due to stretching.

<Example 1>
A reactor equipped with a stirrer, a temperature sensor, a cooling tube, and a nitrogen introduction tube, a first SEBS triblock copolymer (manufactured by Asahi Kasei Co., Ltd., Tough Tech (registered trademark) P1083, olefinic double bond amount 2.01 mmol / g, styrene unit content 18.3% by mass, refractive index 1.500, weight average molecular weight 94,000, number average molecular weight 64,000) in 3 parts, 2nd SEBS triblock copolymer (Asahi Kasei Co., Ltd.) , Tough Tech (registered trademark) H1052, olefinic double bond amount 0.27 mmol / g, styrene unit content 15.7 mass%, refractive index 1.500, weight average molecular weight 94,000, number average molecular weight 6. 90,000) 7 parts, methyl methacrylate (MMA) 73.8 parts, methyl 2- (hydroxymethyl) acrylate (MHMA) 10.8 parts, n-dodecyl mercaptan (nDM) 0.025 parts, 100 parts of toluene was charged as a polymerization solvent, and the temperature was raised to 105 ° C. while passing nitrogen through the mixture. Then, 0.06 part of t-butylperoxyisopropyl carbonate (Kayacarbon (registered trademark) Bic75, manufactured by Kayaku Akzo Corporation) was added as an initiator. After confirming the start of the polymerization reaction by increasing the temperature of the polymerization solution, the addition of styrene (St) and t-butylperoxyisopropyl carbonate was started. 5.4 parts of styrene (St) was added at a constant rate over 3 hours, and 0.185 parts of t-butylperoxyisopropyl carbonate diluted with 1 part of toluene was added dropwise at a constant rate over 4 hours. However, solution polymerization was carried out at 105 to 110 ° C., and after the addition of t-butylperoxyisopropyl carbonate was completed, aging was further carried out for 2 hours. 0.075 parts of stearyl phosphate was added thereto as a cyclization catalyst, and a cyclization condensation reaction for forming a lactone ring structure was carried out under reflux at 90 to 110 ° C. for 2 hours. Sulfur-based antioxidants (ADEKA, ADEKA STAB (registered trademark) AO-412S) and hindered phenol-based antioxidants (ADEKA, ADEKA STAB (registered trademark) AO-60) are added to the obtained reaction solution, respectively. 0.05 part was added. As a result, a (meth) acrylic copolymer that is polymerized from MMA, MHMA, and St and has a lactone ring structure in the main chain, and the copolymer chain is derived from the diene / olefin of the SEBS triblock copolymer chain. A resin composition containing the graft copolymer bonded to the unit was obtained. The conversion rate of MMA calculated from the amount of residual monomers in the polymerization solution at the end of the reaction was 94%, the conversion rate of MHMA was 94%, and the conversion rate of St was 99%. The composition ratio (mass basis) of the (meth) acrylic copolymer chain bonded to the SEBS triblock copolymer chain calculated from the conversion rate is MMA: MHMA: St. = 82.6: 11.9: 5.5, and the content of the ring structure unit was 22.0% by mass.
Next, the obtained polymerization solution was passed through a multi-tube heat exchanger heated to 240 ° C. to complete the cyclization condensation reaction. After that, the cyclized condensed polymer was subjected to a barrel temperature of 250 ° C., one rear vent, four fore vents (referred to as the first, second, third and fourth vents from the upstream side) and the first vent. A vent type screw twin-screw extruder (L / D = 52) equipped with a side feeder between the 3 vents and the 4 vents and a leaf disk type polymer filter (filtration accuracy 5 μm) arranged at the tip, 33. Introduced at a processing speed of 7 parts / hour (converted to resin amount). At that time, ion-exchanged water was added from behind the second vent at an addition rate of 0.50 part / hour, and 0.66 part of an ultraviolet absorber (ADEKA, ADEKA STAB (registered trademark) LA-F70) was added to toluene 1 .The solution dissolved in 23 parts is charged from behind the 3rd vent at a charging rate of 0.64 parts / hour, and ion-exchanged water is charged from behind the 4th vent at a charging rate of 0.50 parts / hour. Then, the volatilization was performed.
After the devolatileization is completed, the resin composition in the heat-melted state left in the extruder is discharged from the tip of the extruder while being filtered by a polymer filter, and after passing through the provided die, a filter having a pore size of 1 μm (manufactured by Organo). , Product name: Micropore filter 1EU), the strands are cooled by a water tank filled with cooling water and kept at a temperature within the range of 30 ± 10 ° C., and the strands are introduced into a cutting machine (polymerizer) to obtain a lactone ring. A lactone ring-based polymer having a structure as a main chain, a graft copolymer in which the copolymer chain is bonded to a unit derived from a diene / olefin of a SEBS triblock copolymer chain, and an ultraviolet absorber (UV absorber). A pellet made of the resin composition (P-1) containing the mixture was obtained.
The weight average molecular weight of the obtained resin composition (P-1) is 138,000, the number average molecular weight is 52,000, the glass transition temperature on the high temperature side is 121 ° C, and the glass transition temperature on the low temperature side is −54 ° C. The refractive index was 1.500. The size of the sea-island structure when the obtained polymerization composition was made into a press film was 140 nm. From the dispersed state shown in FIG. 1, it was determined to have a phase-separated state. The destructive energy was 40 mJ or more. When the film of the resin composition (P-1) was stretched to Tg + 24 ° C., the number of MITs in the stretched film having a thickness of 40 μm was 10,000 times or more, and the film had tough strength. The internal haze of the stretched film having a thickness of 40 μm was 0.06% (0.14% per 100 μm thickness). Further, the Re of the stretched film having a thickness of 40 μm was 0.1 nm and the Rth was +6.3 nm, confirming that the stretched film was a low retardation film.

<Example 2>
The polymerization solution is the same as in Example 1, and the polymerization solution is introduced at a processing rate of 33.7 parts / hour (converted to the amount of resin) under the charging conditions of the twin-screw extruder, and the second, third, and fourth vents are vented. Ion-exchanged water was added from the back of each at a charging rate of 0.50 part / hour, and treatment was carried out with an extruder in the same manner as in Example 1 except that devolatile was performed, and the lactone ring structure was the backbone. A pellet made of a resin composition (P-2) containing the lactone ring polymer contained in the above and a graft copolymer in which the copolymer chain is bonded to a diene / olefin-derived unit of the SEBS triblock copolymer chain. Obtained.
The weight average molecular weight of the obtained resin composition (P-2) is 137,000, the number average molecular weight is 51,000, the glass transition temperature on the high temperature side is 122 ° C, and the glass transition temperature on the low temperature side is −54 ° C. The refractive index was 1.500. When the obtained polymerization composition was made into a press film, the size of the sea-island structure was 120 nm, and it was judged to have a phase-separated structure as in Example 1. The destructive energy was 40 mJ or more. When the film of the resin composition (P-2) was stretched to Tg + 24 ° C., the number of MITs in the stretched film having a thickness of 40 μm was 10,000 times or more, and the film had tough strength. The internal haze of the stretched film having a thickness of 40 μm was 0.07% (0.18% per 100 μm thickness). Further, the Re of the stretched film having a thickness of 40 μm was 0.1 nm and the Rth was +3.0 nm, confirming that the stretched film was a low retardation film.

<Example 3>
A reactor equipped with a stirrer, a temperature sensor, a cooling tube, and a nitrogen introduction tube contains a third SEBS triblock copolymer (A1536 manufactured by Kraton, olefinic double bond amount 0.08 mmol / g, styrene unit). The amount is 38.8% by mass, the refractive index is 1.519), 15 parts, methyl methacrylate (MMA) is 65.7 parts, phenylmaleimide (PMI) is 15.7 parts, and n-dodecyl mercaptan (nDM) is 0. 07 parts and 100 parts of toluene were charged as a polymerization solvent, and the temperature was raised to 105 ° C. while passing nitrogen through them. Then, 0.058 parts of t-butylperoxyisopropyl carbonate (Kayacarbon (registered trademark) Bic75, manufactured by Kayaku Akzo Corporation) was added as an initiator. After confirming the start of the polymerization reaction by increasing the temperature of the polymerization solution, the addition of styrene (St) and t-butylperoxyisopropyl carbonate was started. 3.6 parts of styrene (St) and 0.115 parts of t-butyl peroxyisopropyl carbonate diluted with 1 part of toluene were added dropwise at a constant rate over 4 hours and solution-polymerized at 105-110 ° C. After the addition of t-butylperoxyisopropyl carbonate was completed, aging was further carried out for 3 hours. As a result, a (meth) acrylic copolymer polymerized from MMA, PMI, and St, and a graft copolymer in which the copolymer chain is bonded to a unit derived from the diene / olefin of the SEBS triblock copolymer chain. A resin composition containing the above was obtained. The conversion rate of MMA calculated from the amount of residual monomers in the polymerization solution at the end of the reaction was 94%, the conversion rate of PMI was 98%, and the conversion rate of St was 99%. The composition ratio (mass basis) of the (meth) acrylic copolymer chain bonded to the SEBS triblock copolymer chain calculated from the conversion rate and the (meth) acrylic copolymer is MMA: PMI: St. = 78: 17.8: 4.8, and the content of the ring structure unit was 17.8% by mass.
Next, the obtained polymer solution was processed in a vent type screw twin-screw extruder (hole diameter: 15 mm, L / D: 45) having one rear vent and two fore vents at 600 g / h in terms of resin. The pellets of the transparent resin composition (P-3) were obtained by introducing at a high speed, devolatile 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 decompression degree of 13.3 to 400 hPa (10 to 300 mmHg). The weight average molecular weight of the obtained resin composition is 139,000, the number average molecular weight is 58,000, the glass transition temperature on the high temperature side is 138 ° C, the glass transition temperature on the low temperature side is -68 ° C, and the refractive index is 1. It was .517. When the obtained resin composition (P-3) was made into a press film, the size of the sea-island structure was 260 nm, and it was judged to have a phase-separated structure as in Example 1. The destructive energy was 40 mJ or more. When the film of the resin composition (P-3) was stretched to Tg + 24 ° C., the number of MITs in the 40 μm stretched film was 3000 times or more, and it had tough strength. The internal haze of the stretched film having a thickness of 40 μm was 0.03% (0.08% per 100 μm thickness). Further, the Re of the stretched film having a thickness of 40 μm was 0.6 nm and the Rth was +3.2 nm, confirming that the stretched film was a low retardation film.

<Comparative Example 1>
When the glass transition temperature of a commercially available PMMA resin (Sumitomo Chemical, Sumipex EX weight average molecular weight 146,000, number average molecular weight 73,000, hereinafter sometimes referred to as resin composition (P-4)) is measured, 107. It was ° C. The stress optical coefficient Cr was -15 × 10 ^-9 Pa ^-1 , and had negative orientation birefringence. Further, the resin composition (P-4) was heat-press molded at 250 ° C. to prepare an unstretched film having a thickness of 160 μm, and Tg + 24 was prepared using a sequential biaxial stretching machine (X-6S manufactured by Toyo Seiki Seisakusho Co., Ltd.). Stretching was carried out at a temperature of ° C. to obtain a stretched film having a thickness of 40 μm. The number of MITs of the stretched film was 700, and the stretched film did not have sufficient strength. The internal haze of the stretched film having a thickness of 40 μm was 0.02% (0.05% per 100 μm thickness). The Re of the stretched film having a thickness of 40 μm was 1.8 nm, and the Rth was -12.0 nm. That is, it was confirmed that the PMMA resin had a negative orientation birefringence.

<Reference example 1>
The same as in Example 1 except that the first SEBS triblock copolymer and the second SEBS triblock copolymer are not added to the reactor provided with the stirrer, the temperature sensor, the cooling tube, and the nitrogen introduction tube. By the method, pellets composed of a resin composition containing a lactone ring-based polymer having a lactone ring structure as a main chain and an ultraviolet absorber (UV absorber) were obtained. Hereinafter, the resin composition obtained in Reference Example 1 may be referred to as a resin composition (P-1-0). The stress optical coefficient Cr of the resin composition (P-1-0) was -3 × 10 ^-9 Pa ^-1 , and had negative birefringence. Further, the resin composition (P-1-0) was hot press-molded at 250 ° C. to prepare an unstretched film having a thickness of 160 μm, and a sequential biaxial stretching machine (manufactured by Toyo Seiki Seisakusho Co., Ltd., X-6S) was used. It was stretched at a temperature of Tg + 24 ° C. to obtain a stretched film of 40 μm. The Re of the stretched film was 0.4 nm and the Rth was −1.5 nm. That is, it was confirmed that the matrix resin containing no graft copolymer bonded to the diene / olefin-derived unit of the SEBS triblock copolymer chain in the resin composition (P-1) has negative orientation birefringence.

<Reference example 2>
The same as in Example 2 except that the first SEBS triblock copolymer and the second SEBS triblock copolymer are not added to the reactor provided with the stirrer, the temperature sensor, the cooling tube, and the nitrogen introduction tube. By the method, pellets composed of a resin composition containing a lactone ring-based polymer having a lactone ring structure in the main chain were obtained. Hereinafter, the resin composition obtained in Reference Example 2 may be referred to as a resin composition (P-2-0). The stress optical coefficient Cr of the resin composition (P-2-0) was -5 × 10 ^-9 Pa ^-1 , and had negative orientation birefringence. Further, the resin composition (P-2-0) was heat-press molded at 250 ° C. to prepare an unstretched film having a thickness of 160 μm, and a sequential biaxial stretching machine (X-6S manufactured by Toyo Seiki Seisakusho Co., Ltd.) was used. The film was stretched at a temperature of Tg + 24 ° C. to obtain a stretched film of 40 μm. The Re of the stretched film was 0.6 nm and the Rth was −2.5 nm. That is, it was confirmed that the matrix resin containing no graft copolymer bonded to the diene / olefin-derived unit of the SEBS triblock copolymer chain in the resin composition (P-2) has negative orientation birefringence.

<Reference example 3>
Polymerization from MMA, PMI, and St in the same manner as in Example 1 except that the third SEBS triblock copolymer is not added to the reactor provided with the stirrer, temperature sensor, cooling tube, and nitrogen introduction tube. Pellets made of the formed (meth) acrylic copolymer were obtained. Hereinafter, the resin composition obtained in Reference Example 3 may be referred to as a resin composition (P-3-0). The stress optical coefficient Cr of the resin composition (P-3-0) was -22 × 10 ^-9 Pa ^-1 , and had negative birefringence. Further, the resin composition (P-3-0) was hot press-molded at 250 ° C. to prepare an unstretched film having a thickness of 160 μm, and a sequential biaxial stretching machine (X-6S manufactured by Toyo Seiki Seisakusho Co., Ltd.) was used. The film was stretched at a temperature of Tg + 24 ° C. to obtain a stretched film of 40 μm. The Re of the stretched film was 2.0 nm and the Rth was -11.1 nm. That is, it was confirmed that in the resin composition (P-3), the matrix resin containing no graft copolymer bonded to the unit derived from the diene / olefin of the SEBS triblock copolymer chain has negative orientation birefringence.

<Reference example 4>
Fourth SEBS triblock copolymer (manufactured by Kraton, G1652, olefinic double bond amount 0.10 mmol / g, styrene unit content 25.9% by mass, refractive index 1.510, weight average molecular weight) in a pressure-resistant tube 80,000, number average molecular weight 68,000), 79.2 parts of methyl methacrylate (MMA), 10.8 parts of styrene (St), 0.1 part of n-dodecyl mercaptan (nDM), initiator 0.5 part of t-butylperoxyisopropyl carbonate (Kayacarboxyl (registered trademark) Bic75, manufactured by Chemicals Axo) was charged as a polymerization solvent, and 100 parts of toluene was charged as a polymerization solvent, and the mixture was sealed with nitrogen. The reaction was carried out in an oil bath at 115 ° C. for 6 hours. The conversion rate of MMA calculated from the amount of residual monomers in the polymerization solution was 76%, and the conversion rate of St was 98%. The composition ratio (mass basis) of the (meth) acrylic copolymer chain bonded to the SEBS triblock copolymer chain calculated from the conversion rate and the (meth) acrylic copolymer is MMA: St = 85. The ratio was 0.0: 15.0, and the obtained polymerization solution was diluted with chloroform and added dropwise to methanol to precipitate the resulting polymer. After that, suction filtration is performed, and the polymer is dried in a vacuum dryer at 100 ° C. for 1 hour, and then dried in a vacuum dryer at 240 ° C. for 1 hour to remove unreacted monomers. A resin composition (P-5) containing a copolymer and a graft copolymer in which the copolymer chain was bonded to a unit derived from the diene / olefin of the SEBS triblock copolymer chain was obtained.
The weight average molecular weight of the obtained resin composition (P-5) is 135,000, the number average molecular weight is 61,000, the glass transition temperature on the high temperature side is 114 ° C, and the glass transition temperature on the low temperature side is −54 ° C. The refractive index was 1.505. When the size of the sea-island structure when the obtained polymerization composition was made into a press film was confirmed, it was 190 nm, and it was judged to have a phase-separated structure as in Example 1. The destructive energy was 40 mJ or more. The film of the resin composition (P-5) was stretched at a temperature of Tg + 24 ° C. to obtain a stretched film of 40 μm. The number of MITs in the stretched film was 3000 times or more, and the stretched film had tough strength. The internal haze of the stretched film having a thickness of 40 μm was 0.08% (0.20% per 100 μm thickness). The stretched film having a thickness of 40 μm had a Re of 0.4 nm and an Rth of −15.5 nm, which was a negative retardation film. As shown in the result of Reference Example 5 described later, when the orientation birefringence of the matrix resin is too large, the morphological compound is caused by the island structure composed of the graft copolymer bonded to the diene / olefin-derived unit of the SEBS triblock copolymer chain. It is considered difficult to obtain a low retardation film by canceling the negative orientation birefringence by refringence.

<Reference example 5>
Pellets made of the resin composition were obtained in the same manner as in Reference Example 4 except that the fourth SEBS triblock copolymer was not added to the pressure resistant tube. Hereinafter, the resin composition obtained in Reference Example 5 may be referred to as a resin composition (P-5-0). The stress optical coefficient Cr of the resin composition (P-5-0) was −70 × 10 ^-9 Pa ^-1 , and had a large negative orientation birefringence. Further, the resin composition (P-5-0) was heat-press molded at 250 ° C. to prepare an unstretched film having a thickness of 160 μm, and a sequential biaxial stretching machine (X-6S manufactured by Toyo Seiki Seisakusho Co., Ltd.) was used. The film was stretched at a temperature of Tg + 24 ° C. to obtain a stretched film of 40 μm. The Re of the stretched film was 4.9 nm and the Rth was -35.5 nm. That is, it was confirmed in the resin composition (P-5) that the matrix resin containing no graft copolymer bonded to the unit derived from the diene / olefin of the SEBS triblock copolymer chain has a large negative orientation birefringence.

Claims (10)

A film in which a phase-separated portion is formed in a matrix, which has positive morphological birefringence based on the phase-separated structure, negative oriented birefringence is introduced into the matrix, and morphological birefringence and oriented birefringence are formed. They cancel each other out
The film is a film containing a polymer chain having a polymer block (a1) having a unit derived from a diene and / or an olefin . It is a film in which a phase-separated portion is formed in a matrix, has positive morphological birefringence based on the phase-separated structure, negative oriented birefringence is introduced into the matrix, and morphological birefringence and oriented birefringence are formed. They cancel each other out
The film is a copolymer having a polymer chain (A) 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. A film containing. A film in which a phase-separated structure is formed in a matrix and the matrix contains a resin (R) having a negative orientation birefringence.
The in-plane retardation Re of the film with respect to light having a wavelength of 589 nm is 10 nm or less, and the phase difference Rth in the thickness direction with respect to light having a wavelength of 589 nm is −10 to 10 nm .
The film is characterized by containing a polymer chain having a polymer block (a1) having a unit derived from a diene and / or an olefin . A film in which a phase-separated structure is formed in a matrix and the matrix contains a resin (R) having a negative orientation birefringence.
The in-plane retardation Re of the film with respect to light having a wavelength of 589 nm is 10 nm or less, and the phase difference Rth in the thickness direction with respect to light having a wavelength of 589 nm is −10 to 10 nm.
The film is a copolymer having a polymer chain (A) 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. A film characterized by containing . The film according to claim 3 or 4 , wherein the stress optical coefficient Cr of the resin (R) is -30.0 × 10 ^-9 Pa ^-1 or more and −0.1 × 10 ^-9 Pa ^-1 or less. The film according to any one of claims 3 to 5, wherein the resin (R) contains a (meth) acrylic polymer (Q). The film according to claim 2 or 4 , wherein the polymer chain (A) is contained in the film in an amount of 0.1 to 20% by mass. The film according to any one of claims 1 to 7, which has a glass transition temperature of 115 ° C. or higher. The film according to any one of claims 1 to 8, wherein the internal haze is 1.0% or less. The film according to any one of claims 1 to 9, wherein the film is a biaxially stretched film having a thickness of 60 μm or less.

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