Dope, film, and method for manufacturing film

Abstract

To provide a technology that combines an ultraviolet absorber having excellent light transmission suppression property at wavelengths around 400 nm and a (meth)acrylic polymer having a ring structure in the main chain without adversely affecting light transmission suppression property or film appearance.SOLUTION: Provided is a dope, which is a dope containing a (meth)acrylic polymer having a ring structure in the main chain and a sulfur atom-containing ultraviolet absorber, and in which the contained amount of the ultraviolet absorber is 0.5 pts.mass or more and 6 pts.mass or less for 100 pts.mass of (meth)acrylic polymer.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to dopes, films, and methods for manufacturing films. In particular, it relates to dopes for optical films, optical films, methods for manufacturing optical films, and organic electroluminescent display devices. [Background technology]

[0002] In recent years, organic electroluminescent (EL) display devices (OLEDs) have become widely used in various applications such as smartphones, wearables, laptops, and televisions. In OLED display devices, it is known that in order to suppress the degradation of the OLED elements within the display device, it is necessary to suppress the transmission of light at wavelengths shorter than the light-emitting region of the OLED elements (380nm to 430nm) (Patent Document 1). For this reason, optical films used in OLED display devices are also required to suppress the transmission of light at wavelengths of 380nm to 430nm.

[0003] For the formation of optical films, (meth)acrylic polymers are preferably used because they offer an excellent balance of various properties such as optical properties, mechanical strength, moldability, and surface hardness. Among the (meth)acrylic polymers, those having a ring structure in the main chain that can form films with good heat resistance are known. The formation of films from compositions containing (meth)acrylic polymers having a ring structure in the main chain is usually carried out by a melt film formation method (Patent Document 2). [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-139108 [Patent Document 2] Japanese Patent Publication No. 2015-147356 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] However, when a film was formed by melt deposition as disclosed in Patent Document 2, using the triazine-based ultraviolet absorber used in Patent Document 1 and a (meth)acrylic polymer having a ring structure in its main chain, it was not possible to sufficiently suppress the transmission of light with wavelengths of 380 nm to 430 nm (especially 400 nm). Therefore, when the triazine-based ultraviolet absorber was replaced with an ultraviolet absorber that has excellent light transmission suppression properties for wavelengths of 380 nm to 430 nm and a film was formed in the same manner, the desired light transmission suppression performance commensurate with the amount of ultraviolet absorber used could not be obtained, and problems such as poor film appearance and contamination of the molding equipment (film roll, etc.) arose due to the ultraviolet absorber bleeding out onto the film surface.

[0006] The present invention has been made in view of the circumstances described above, and its purpose is to provide a technology for combining an ultraviolet absorber with excellent light transmission suppression properties around a wavelength of 400 nm and a (meth)acrylic polymer having a ring structure in its main chain, without adversely affecting light transmission suppression properties or film appearance. [Means for solving the problem]

[0007] As a result of diligent research to solve the aforementioned problems, the present inventors have found that, instead of using a melt-forming method, a solution-forming method using a dope containing a (meth)acrylic polymer having a ring structure in its main chain and an ultraviolet absorber containing sulfur atoms in a specific ratio can be used to obtain a film that maintains excellent ultraviolet absorption properties, and more preferably, does not cause problems such as bleeding out of the ultraviolet absorber during film formation or contamination of the molding equipment, and that this technology is particularly effective for films with small phase differences, thus completing the present invention. In other words, the present invention is defined by the following constituent elements. [1] A dope comprising a (meth)acrylic polymer having a ring structure in the main chain and an ultraviolet absorber containing a sulfur atom, A dope containing an ultraviolet absorber in an amount of 0.5 parts by mass or more and 6 parts by mass or less per 100 parts by mass of (meth)acrylic polymer. [2] The dope according to [1], wherein the ultraviolet absorber contains a compound represented by the following formula (1). [Chemical formula] [In formula (1), L represents a divalent or higher linking group, a represents an integer of 2 or more, and each A independently represents a group represented by the following formula (2).] [Chemical formula] [In formula (2), R 1 represents a cyano group, an acyl group, a carboxyl group, a carboxylic acid ester group, or an amide group, R 2 represents a hydrogen atom, a cyano group, an acyl group, a carboxyl group, a carboxylic acid ester group, an amide group, a hydrocarbon group, or a heteroaryl group, R 1 and R 2 are both an acyl group, a carboxylic acid ester group, or an amide group, R 1 and R 2 may be linked to each other to form a ring, R 3 represents a hydrogen atom or an alkyl group, R 4 represents a hydrogen atom, an organic group, or a polar functional group, and a plurality of R 4 may be the same as or different from each other, * represents the bonding site with the linking group L of formula (1).] [3] The dope according to [1] or [2], wherein the ring structure in the main chain of the (meth)acrylic polymer is at least one selected from the group consisting of a lactone ring structure, a glutarimide structure, a glutaric anhydride structure, a maleic anhydride structure, and an N-substituted maleimide structure. [4] A method for producing a film, comprising the step of preparing the dope according to any one of [1] to [3], and the step of casting or coating the adjusted dope on a support and then drying it. [5] A film containing a (meth)acrylic polymer having a ring structure in the main chain and an ultraviolet absorber, The light transmittance at a wavelength of 400 nm is 15% or less. A film having an in-plane phase difference Re of 10 nm or less for light with a wavelength of 589 nm, and an absolute value of the thickness-direction phase difference Rth of 20 nm or less for light with a wavelength of 589 nm. [6] The film described in [5] having an internal haze of 1.0% or less. [7] The film according to [5] or [6], wherein the ultraviolet absorber comprises a compound represented by the following formula (1). [ka] [In formula (1), L represents a linking group with two or more valencies, a represents an integer of 2 or more, and A independently represents a group shown in formula (2) below.] [ka] [In formula (2), R 1 represents a cyano group, acyl group, carboxyl group, carboxylic acid ester group, or amide group. R 2 represents a hydrogen atom, a cyano group, an acyl group, a carboxyl group, a carboxylic acid ester group, an amide group, a hydrocarbon group, or a heteroaryl group. R 1 and R 2 If both are acyl groups, carboxylic acid ester groups, or amide groups, R 1 and R 2 They may be connected to each other to form a ring. R 3 represents a hydrogen atom or an alkyl group, R 4 R represents a hydrogen atom, an organic group, or a polar functional group, and multiple R 4 They may be the same or different from each other. * represents the bonding site with the linking group L in formula (1). [8] The film according to any one of [5] to [7], wherein the ring structure of the main chain of the (meth)acrylic polymer is at least one selected from the group consisting of a lactone ring structure, a glutarimide structure, a glutaric acid anhydride structure, a maleic acid anhydride structure, and an N-substituted maleimide structure. An organic electroluminescent display device comprising the film described in any of [9] [5] to [8]. [Effects of the Invention]

[0008] According to the present invention, it is possible to obtain a film that maintains excellent ultraviolet absorption properties, and more preferably, problems such as bleeding out of the ultraviolet absorber during film formation and contamination of the molding equipment can be suppressed. Furthermore, it is possible to provide a film with excellent ultraviolet absorption properties and small phase difference. [Modes for carrying out the invention]

[0009] 1. Dope Doping refers to a resin solution that is formed into a film using a solution-based film-forming method. The dope of the present invention comprises a (meth)acrylic polymer having a ring structure in its main chain and an ultraviolet absorber containing sulfur atoms, characterized in that the content of the ultraviolet absorber is 0.5 parts by mass or more and 6 parts by mass or less per 100 parts by mass of the (meth)acrylic polymer.

[0010] 1.1 (Meth)acrylic polymers The (meth)acrylic polymer contained in the dope of the present invention has a ring structure in its main chain. (Meth)acrylic polymers having a ring structure in their main chain have a high glass transition temperature (Tg), for example, 110°C or higher. Therefore, a dope containing a (meth)acrylic polymer having a ring structure in its main chain can form a film with excellent heat resistance.

[0011] (Meth)acrylic polymers refer to polymers having (meth)acrylic acid, (meth)acrylic acid esters, or derivatives thereof (hereinafter, these may be collectively referred to as (meth)acrylic monomers) as monomer units. In addition, unless otherwise specified in this invention, "(meth)acrylic acid" means acrylic acid or methacrylic acid, and "C 3-12 " means "3 or more carbon atoms and 12 or less".

[0012] Examples of (meth)acrylic acid esters include alkyl (meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, n-butyl (meth)acrylate, t-butyl (meth)acrylate, n-hexyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate; and aralkyl (meth)acrylates such as benzyl (meth)acrylate (preferably C methacrylate). 2-20 Examples include esters of (meth)acrylic acid with hydroxycyclic saturated hydrocarbons (preferably hydroxycyclic saturated hydrocarbons with 5 to 20 carbon atoms), such as aralkyl; cyclohexyl (meth)acrylate and dicyclopentanyl (meth)acrylate. The (meth)acrylic acid ester is preferably a methacrylic acid ester, more preferably an alkyl methacrylate, and even more preferably C methacrylate. 1-10 It is an alkyl group, and more preferably C methacrylate. 1-7 It is alkyl, and more preferably C methacrylate. 1-4 It is an alkyl group, and particularly preferably C methacrylate. 1-2 It is alkyl.

[0013] Examples of (meth)acrylic acid ester derivatives include hydroxyl group-introduced derivatives, such as hydroxyalkyl (meth)acrylates like 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2,3,4,5,6-pentahydroxyhexyl (meth)acrylate, and 2,3,4,5-tetrahydroxypentyl (meth)acrylate; and alkyl α-(1-hydroxyalkyl)acrylate. Hydroxyalkyl (meth)acrylates include hydroxyC (meth)acrylate. 1-20 Alkyl is preferred, and (meth)acrylate hydroxy C 1-15 Alkyl is more preferred, and (meth)acrylate hydroxy C 1-10 Alkyl is more preferred, and (meth)acrylate hydroxy C 1-5 Alkyl is even more preferable. α-(1-hydroxyalkyl)alkyl acrylates include α-(1-hydroxyC1-20 C alkyl acrylate 1-20 Alkyl is preferred, α-(1-hydroxyC 1-20 C alkyl acrylate 1-20 Alkyl compounds include α-(hydroxymethyl)acrylate C, such as methyl α-(hydroxymethyl)acrylate, ethyl α-(hydroxymethyl)acrylate, isopropyl α-(hydroxymethyl)acrylate, n-butyl α-(hydroxymethyl)acrylate, and t-butyl α-(hydroxymethyl)acrylate. 1-20 Alkyl; α-(1-hydroxyethyl)acrylate such as methyl α-(1-hydroxyC 2-20 C alkyl acrylate 1-20 It contains alkyl groups, etc.

[0014] Furthermore, (meth)acrylic acid ester derivatives include β-C such as methyl crotate. 1-10 C alkyl acrylate 1-10 This also includes alkyl groups; halogen-introduced derivatives such as chloromethyl (meth)acrylate and 2-chloroethyl (meth)acrylate; and ether-bonded derivatives such as dicyclopentanyloxyethyl (meth)acrylate.

[0015] The (meth)acrylic acid ester derivative is preferably a hydroxyl group-introduced derivative, more preferably α-(1-hydroxyalkyl)alkyl acrylate, and even more preferably α-(1-hydroxyC 1-20 C alkyl acrylate 1-20 It is alkyl, and more preferably α-(hydroxymethyl)acrylate C 1-20 It is alkyl.

[0016] Examples of (meth)acrylic acid derivatives include compounds obtained by hydrolyzing the ester bond of the methacrylic acid ester derivative, such as crotonic acid, α-(hydroxymethyl)acrylic acid, and α-hydroxyalkylacrylic acids such as 2-(1-hydroxyethyl)acrylic acid.

[0017] The (meth)acrylic monomers that the (meth)acrylic polymer has as monomer units may be a single unit or a combination of two or more types. It is preferable that the (meth)acrylic monomers contain (meth)acrylic acid or (meth)acrylic acid ester as essential units, and it is more preferable that they contain (meth)acrylic acid ester (especially methacrylic acid ester) as essential units. The content of the essential units is, for example, 30% by mass or more, preferably 40% by mass or more, more preferably 50% by mass or more, even more preferably 55% by mass or more, even more preferably 60% by mass or more, particularly preferably 65% ​​by mass or more in the (meth)acrylic polymer, and for example, 97% by mass or less, preferably 95% by mass or less, more preferably 90% by mass or less, and even more preferably 85% by mass or less. Furthermore, the content ratio of each constituent unit in the (meth)acrylic polymer is determined by dissolving the (meth)acrylic polymer in a deuterated solvent. 1 It can be determined by measuring 1H-NMR and calculating the peak area ratio corresponding to each constituent unit.

[0018] The ring structure in the main chain of the (meth)acrylic polymer is preferably at least one selected from the group consisting of a lactone ring structure, a glutarimide structure, a glutaric acid anhydride structure, a maleic acid anhydride structure, and an N-substituted maleimide structure. Furthermore, having a ring structure in the main chain means that at least one carbon atom forming the ring structure is included in the main chain of the (meth)acrylic polymer.

[0019] The lactone ring structure is, for example, a 4-membered ring or an 8-membered ring, and is preferably a 5-membered or 6-membered ring due to its excellent ring structure stability. It is more preferably a 6-membered ring when the main chain of the (meth)acrylic polymer contains two or more carbon atoms that form the ring structure, and is preferably a 5-membered ring when the main chain of the (meth)acrylic polymer contains one carbon atom that forms the ring structure. Examples of units having a lactone ring structure include the structural unit shown in the following formula (1X) and the structural unit shown in the following formula (11X).

[0020] [ka]

[0021] In the above equation (1X), R 1a , R 2a and R 3a These are, independently of each other, a hydrogen atom or an organic residue having 1 to 20 carbon atoms, and such organic residue may contain an oxygen atom. Examples of organic residues in formula (1X) include saturated aliphatic hydrocarbon groups (alkyl groups, etc.) having 1 to 20 carbon atoms, such as methyl, ethyl, and propyl groups; unsaturated aliphatic hydrocarbon groups (alkenyl groups, etc.) having 2 to 20 carbon atoms, such as ethenyl and propenyl groups; aromatic hydrocarbon groups (aryl groups, etc.) having 6 to 20 carbon atoms, such as phenyl and naphthyl groups; and groups in which one or more hydrogen atoms in these saturated aliphatic hydrocarbon groups, unsaturated aliphatic hydrocarbon groups, or aromatic hydrocarbon groups are substituted with at least one group selected from hydroxyl, carboxyl, ether, and ester groups, with alkyl groups being preferred.

[0022] [ka]

[0023] In the above equation (11X), R 11a , R 12a , R 13a and R 14a Each is independently a hydrogen atom or a hydrocarbon group having 1 to 18 carbon atoms, and X a Ha-(CR 11a R 12a )-and-(CR 13a R 14a )- A single bond connecting or -(CR 15a R 16a )- and R 15a , R 16a These are, independently of each other, a hydrogen atom or a hydrocarbon group having 1 to 18 carbon atoms. In equation (11X), X aWhen it is a single bond, the structural unit shown in formula (11X) has a five-membered lactone ring structure, X a ga-(CR 15a R 16a In the case of ), the structural unit shown in formula (11X) has a six-membered lactone ring structure. Examples of hydrocarbon groups in formula (11X) include saturated aliphatic hydrocarbon groups (alkyl groups, etc.) having 1 to 18 carbon atoms, such as methyl, ethyl, and propyl groups; unsaturated aliphatic hydrocarbon groups (alkenyl groups, etc.) having 2 to 18 carbon atoms, such as ethenyl and propenyl groups; and aromatic hydrocarbon groups (aryl groups, etc.) having 6 to 18 carbon atoms, such as phenyl and naphthyl groups. Alkyl groups are preferred, and alkyl groups having 1 to 10 carbon atoms are more preferred.

[0024] Examples of units having the glutaric anhydride structure or the glutarimide structure include the structural unit shown in the following formula (2X). In the following formula (2X), X 1 When is an oxygen atom, it becomes a form having a glutaric anhydride structure, X 1 When it is a nitrogen atom, it takes on the form of a glutarimide structure.

[0025] [ka]

[0026] In the above equation (2X), R 4a , R 5a These are, independently of each other, a hydrogen atom or a methyl group, and X 1 X is an oxygen atom or a nitrogen atom. 1 When R is an oxygen atom, 6a It does not exist, X 1 When is a nitrogen atom, R 6a This is a hydrogen atom, a linear alkyl group having 1 to 6 carbon atoms (methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group), a cyclopentyl group, a cyclohexyl group, or a phenyl group.

[0027] Examples of units having the maleic anhydride structure or the N-substituted maleimide structure include the structure shown in the following formula (3X). In the following formula (3X), X 2 When is an oxygen atom, it becomes a form having a maleic anhydride structure, X 2 When is a nitrogen atom, it takes on an embodiment having an N-substituted maleimide structure.

[0028] [ka]

[0029] In the above equation (3X), R 7a , R 8a These are, independently of each other, a hydrogen atom or a methyl group, and X 2 X is an oxygen atom or a nitrogen atom. 2 When R is an oxygen atom, 9a It does not exist, X 2 When is a nitrogen atom, R 9a These are a hydrogen atom, a linear alkyl group having 1 to 6 carbon atoms (methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group), a cyclopentyl group, a cyclohexyl group, a benzyl group, or a phenyl group.

[0030] The content of the ring structure in the main chain of the (meth)acrylic polymer is, for example, 1% by mass or more, preferably 5% by mass or more, more preferably 10% by mass or more, for example, 70% by mass or less, preferably 50% by mass or less, and more preferably 45% by mass or less. It is preferable that the content of the ring structure in the main chain of the (meth)acrylic polymer is within the above range because it is possible to improve the heat resistance of the polymer while also achieving good phase difference of the film. The mass of the ring structure refers to the total mass of the constituent elements of the ring and the groups other than the main chain that are bonded to the constituent elements. For example, in the structural unit shown in formula (1X) above, the constituent elements of the ring are five carbon elements and one oxygen element, and the group other than the main chain that is bonded to the constituent elements of the ring is -R 1a ,-COOR 2a , -R 3aThe total mass of the ,=O, and the three -H atoms represents the mass of the ring structure.

[0031] The ring structure in the main chain of the (meth)acrylic polymer can be introduced, for example, by the following methods (i) or (ii). (i) Introduction by copolymerizing a (meth)acrylic monomer with a monomer capable of forming a ring structure in the main chain by copolymerization. (ii) A monomer composition containing (meth)acrylic acid monomers is polymerized and then introduced by a cyclization reaction.

[0032] Examples of monomers capable of forming a ring structure in the main chain by the copolymerization include maleic acid monomers such as maleic anhydride, maleic acid, monoalkyl esters and dialkyl esters of maleic acid; maleimide monomers such as maleimide, methyl maleimide, ethyl maleimide, propyl maleimide, butyl maleimide, hexyl maleimide, octyl maleimide, dodecyl maleimide, stearyl maleimide, phenyl maleimide, and cyclohexyl maleimide; and lactone ring-containing monomers such as α-methylene-γ-butyrolactone, α-methylene-4-methyl-γ-butyrolactone, α-methylene-3-methyl-γ-butyrolactone, α-methylene-4,4-dimethyl-γ-butyrolactone, and α-methylene-δ-valerolactone. Using the maleic acid monomer, a structure derived from malean anhydride can be introduced into the main chain of the (meth)acrylic resin; using the maleimide monomer, a structure derived from N-substituted maleimide can be introduced into the main chain of the (meth)acrylic resin; and using the lactone ring-containing monomer, a (methylene)lactone ring structure can be introduced into the main chain. When introducing a ring structure by method (i), the monomer capable of forming a ring structure in the main chain by copolymerization is preferably 1% by mass or more, more preferably 5% by mass or more, and even more preferably 10% by mass or more in the (meth)acrylic polymer, for example, 70% by mass or less, preferably 60% by mass or less, and more preferably 50% by mass or less.

[0033] Methods for introducing a ring structure using method (ii) include, for example, the following methods (ii-1) to (ii-3). (ii-1) A hydroxyl group-containing (meth)acrylic monomer A, such as α-(1-hydroxyalkyl)alkyl acrylate, is homopolymerized, or a hydroxyl group-containing (meth)acrylic monomer A is copolymerized with a (meth)acrylic monomer B, such as (meth)acrylic acid or (meth)acrylic acid ester, to introduce a hydroxyl group and an ester group or carboxyl group into the molecular chain, and then a lactone ring structure is introduced by causing dealcoholization or dehydration cyclization condensation between these hydroxyl groups and the ester group or carboxyl group. (ii-2) In a copolymer of (meth)acrylic acid ester and (meth)acrylic acid, a glutaric acid anhydride structure is introduced by causing intramolecular dealcoholization cyclization. (ii-3) In a (meth)acrylic acid ester polymer, a glutarimide structure is introduced by inducing imidation with an imidizing agent such as methylamine.

[0034] When introducing a ring structure by the method of (ii-1), the hydroxyl group-containing (meth)acrylic monomer A is a hydroxyl group-introduced derivative as a (meth)acrylic acid ester derivative as described above, and the preferred embodiment is the same. The (meth)acrylic monomer B is a (meth)acrylic acid or (meth)acrylic acid ester as described above, and the preferred embodiment is the same. When copolymerizing the hydroxyl group-containing (meth)acrylic monomer A and the (meth)acrylic monomer B, the content of the hydroxyl group-containing (meth)acrylic monomer A is, for example, 1 part by mass or more, preferably 5 parts by mass or more, more preferably 8 parts by mass or more, and even more preferably 10 parts by mass or more, per 100 parts by mass of (meth)acrylic monomer B, for example, 50 parts by mass or less, preferably 40 parts by mass or less, and more preferably 30 parts by mass or less.

[0035] The (meth)acrylic polymer may have structural units introduced by copolymerizing the (meth)acrylic monomer with other monomers other than monomers capable of forming a ring structure in the main chain by copolymerization. Such other monomers are not particularly limited as long as they are compounds having polymerizable double bonds, and examples include styrene monomers such as styrene, vinyltoluene, α-methylstyrene, α-hydroxymethylstyrene, and α-hydroxyethylstyrene; vinyl ester monomers such as vinyl acetate, vinyl propionate, vinyl pivalate, vinyl benzoate, and vinyl cinnamate; fumaric acid monomers such as fumaric acid, monoalkyl esters and dialkyl esters of fumaric acid; nitrogen-containing heterocyclic vinyl compounds such as N-vinylpyrrolidone and N-vinylcarbazole; vinyl nitriles such as acrylonitrile and methacrylonitrile; vinyl alcohols such as metharyl alcohol and allyl alcohol; olefins such as ethylene, propylene, and 4-methyl-1-pentene; 2-hydroxymethyl-1-butene; methyl vinyl ketone; and the like. Other preferred monomers include styrene monomers and nitrogen-containing heterocyclic vinyl compounds, with styrene monomers being more preferred. One or more of these monomers may be used. By using monomers with a ring structure in their side chains, such as styrene monomers, it is possible to improve the phase difference of the film. Monomers without a ring structure can also be used as appropriate to adjust the phase difference.

[0036] Other monomers in the (meth)acrylic polymer are, for example, 0% by mass or more, preferably 1% by mass or more, for example, 50% by mass or less, preferably 30% by mass or less, more preferably 20% by mass or less, even more preferably 10% by mass or less, and even more preferably 5% by mass or less.

[0037] The total content of constituent units derived from (meth)acrylic monomers (i.e., constituent units derived from (meth)acrylic acid units, (meth)acrylic acid ester units, and their derivative units) in all constituent units of the (meth)acrylic polymer is preferably 40% by mass or more, more preferably 50% by mass or more, even more preferably 55% by mass or more, and even more preferably 60% by mass or more, from the viewpoint of film transparency. The upper limit is, for example, 100% by mass or less.

[0038] Any of the following methods can be used to produce (meth)acrylic polymers: bulk polymerization, solution polymerization, emulsion polymerization, or suspension polymerization. However, solution polymerization is preferred because it is highly safe and has a low risk of contamination. Furthermore, suspension polymerization of monomers in the presence of a dispersion stabilizer is also preferred because it allows for easy polymerization control.

[0039] When a cyclization reaction is carried out after a polymerization reaction, it is preferable to carry out the cyclization reaction in the presence of a cyclization catalyst. As the cyclization catalyst, at least one selected from the group consisting of acids, bases, and their salts can be used. Acids, bases, and their salts may be organic or inorganic, and are not particularly limited. In particular, it is preferable to use an organophosphorus compound or a compound containing an alkali metal as the catalyst for the cyclization reaction. By using an organophosphorus compound or a compound containing an alkali metal as a cyclization catalyst, the cyclization condensation reaction can be carried out efficiently, and the coloration of the resulting dope can be reduced.

[0040] After the solution polymerization reaction (and cyclization reaction if necessary), it is preferable to perform post-treatment including a defoliation step. The defoliation process is a treatment process that removes volatile components such as solvents and residual monomers. If defoliation is insufficient, there will be a large amount of residual volatile components in the (meth)acrylic polymer, which may cause foaming during molding and lead to molding defects.

[0041] The apparatus used for devolatilization is not particularly limited, but for example, an autoclave, a kettle reactor, an apparatus consisting of a heat exchanger and a devolatilization tank, an extruder with a vent, etc., can be used, and a dryer may also be used.

[0042] When using a vented extruder for devolatilization, the extruder preferably has a cylinder and a screw located inside the cylinder, and is equipped with a heating means. The cylinder preferably has one or more vents, and the vents are more preferably located at least downstream of the raw material input section with respect to the transfer direction within the extruder, and may also be located upstream of the raw material input section. Devolatilization proceeds as the polymer supplied to the extruder is transferred from the upstream to the downstream side of the extruder while being kneaded by the screw. A die is preferably provided on the downstream side of the extruder, and the polymer can be molded into a predetermined shape by being discharged from the die. For example, pellets can be produced by finely cutting a polymer molded into a rod shape. A polymer filter is also preferably provided in the die section of the extruder.

[0043] The devolatilization treatment temperature is preferably in the range of 150°C to 350°C, and more preferably in the range of 200°C to 300°C. If the devolatilization treatment temperature is lower than 150°C, devolatilization will be insufficient and a large amount of residual volatile matter will remain, which is a problem. If the devolatilization treatment temperature is higher than 350°C, discoloration and decomposition will occur, which is a problem and therefore undesirable. The degree of reduced pressure during the devolatilization treatment is preferably 13.3 hPa or higher (for example, about 13.3 hPa to 800 hPa).

[0044] After the suspension polymerization reaction, it is preferable to recover the (meth)acrylic polymer as particles (powder) by solid-liquid separation of the suspension containing the (meth)acrylic polymer. The solid-liquid separation method can be selected from filtration, centrifugation, spray drying, and combinations thereof, and a flocculant may be used if necessary. Furthermore, it is preferable to dry the (meth)acrylic polymer particles obtained by solid-liquid separation using a dryer such as a hot air dryer.

[0045] The dope of the present invention may also contain other polymers other than the (meth)acrylic polymer having a ring structure in its main chain, as long as it does not impair the effects of the present invention.

[0046] Other polymers include, for example, (meth)acrylic polymers that do not have a ring structure in the main chain; olefin polymers such as polyethylene, polypropylene, ethylene-propylene polymer, and poly(4-methyl-1-pentene); halogen-containing polymers such as vinyl chloride and chlorinated vinyl resin; styrene polymers such as polystyrene, styrene-methyl methacrylate copolymer, styrene-acrylonitrile copolymer, and acrylonitrile-butadiene-styrene copolymer; polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; polyamides such as nylon 6, nylon 66, and nylon 610; polyacetals; polycarbonates; polyphenylene oxide; polyphenylene sulfide; polyether ether ketone; polysulfone; polyether sulfone; polyoxybenzone; polyamide-imide; cycloolefin polymers; cellulose derivatives such as triacetylcellulose, diacetylcellulose, and cellulose pupionate; elastic organic fine particles such as polybutadiene rubber and acrylic rubber; and rubbery polymers such as ABS resin and ASA resin blended with (meth)acrylic rubber. In particular, polymers without a ring structure and polymers with a ring structure in their side chains can adjust the phase difference in films containing (meth)acrylic polymers with a ring structure in their main chain. Therefore, by appropriately controlling the content ratio of these other polymers, it is possible to reduce the phase difference in the resulting film. In the dope, the total content of polymers other than (meth)acrylic polymers having a ring structure in the main chain is preferably 100 parts by mass or less, more preferably 40 parts by mass or less, even more preferably 10 parts by mass or less, even more preferably 5 parts by mass or less, and may even be 0 parts by mass, per 100 parts by mass of (meth)acrylic polymer having a ring structure in the main chain.

[0047] The weight-average molecular weight (Mw) of the (meth)acrylic polymer having a ring structure in the main chain is, for example, 80,000 or more, preferably 100,000 or more, more preferably 105,000 or more, and even more preferably 110,000 or more, and for example, 500,000 or less, preferably 400,000 or less, and more preferably 350,000 or less. By having the weight-average molecular weight of the (meth)acrylic polymer having a ring structure in the main chain within the above range, it is possible to obtain a dope that maintains the strength required for a film while also having good fluidity during molding.

[0048] The number-average molecular weight (Mn) of the (meth)acrylic polymer having a ring structure in its main chain is, for example, 30,000 or more, preferably 35,000 or more, more preferably 40,000 or more, and for example, 250,000 or less, preferably 225,000 or less, more preferably 200,000 or less. By having the number-average molecular weight of the (meth)acrylic polymer having a ring structure in its main chain within the above range, it is possible to obtain a dope that maintains the necessary strength as a film while also having good fluidity during molding.

[0049] (Meth)acrylic polymers having a ring structure in the main chain preferably have a glass transition temperature of 110°C or higher. Having a glass transition temperature of 110°C or higher provides excellent heat resistance. (Meth)acrylic polymers having a ring structure in the main chain may have multiple glass transition temperatures of 110°C or higher. The glass transition temperature of (meth)acrylic polymers having a ring structure in the main chain is more preferably 115°C or higher, and even more preferably 120°C or higher. From the viewpoint of improving processability during molding, the glass transition temperature of (meth)acrylic polymers having a ring structure in the main chain is preferably less than 300°C, more preferably 200°C or lower, and even more preferably 180°C or lower. The glass transition temperature (Tg) of a (meth)acrylic polymer having a ring structure in its main chain can be determined by the starting point method in accordance with the provisions of JIS K7121.

[0050] 1.2 UV absorbers The ultraviolet absorber contained in the dope of the present invention contains a sulfur atom. As the ultraviolet absorber containing a sulfur atom, by containing a sulfur atom, it exhibits a sharp absorption peak in the ultraviolet to violet region, and also has excellent light transmission suppression property for light with a wavelength of 380 nm to 430 nm, and particularly excellent light transmission suppression property for light near a wavelength of 400 nm. An ultraviolet absorber is preferred.

[0051] Examples of the ultraviolet absorber containing a sulfur atom of the present invention include compounds represented by the following formula (1).

[0052]

Chemical formula

[0053]

Chemical formula

[0054] In the group A represented by formula (2), R 1 (or R2 ) may be in the cis position or the trans position with respect to R. 3

[0055] R 1 and R 2 Examples of the acyl group (alkanoyl group) of R and R include methanoyl group, ethanoyl group, propanoyl group, butanoyl group, pentanoyl group, hexanoyl group, heptanoyl group, octanoyl group, nonanoyl group, decanoyl group, undecanoyl group, dodecanoyl group, tridecanoyl group, tetradecanoyl group, pentadecanoyl group, hexadecanoyl group, heptadecanoyl group, octadecanoyl group, nonadecanoyl group, eicosanoyl group, etc. The acyl group may be substituted with an aryl group, an alkoxy group, a halogeno group, a hydroxyl group, etc. for a part of hydrogen atoms. The alkyl group in the acyl group may be linear or branched. The number of carbon atoms of the acyl group (carbon atoms excluding substituents) is preferably 2 to 21, more preferably 2 to 11, and still more preferably 2 to 6.

[0056] R 1 and R 2 The carboxylic acid ester group of R and R is represented by the formula: *-C(=O)-O-R 11 where * represents the bonding site to the carbon atom of the ethylene double bond in formula (2). In this formula, R 11 represents a hydrocarbon group, preferably an alkyl group, an aryl group, or an aralkyl group.

[0057] R 11Examples of alkyl groups include linear or branched alkyl groups such as methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, t-butyl, pentyl, hexyl, 2-ethylhexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, and icosyl groups; and cyclic (alicyclic) alkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, and cyclodecyl groups. Some of the hydrogen atoms in the alkyl group may be substituted with alkoxy, aryl, cyano, halogeno, hydroxyl, or nitro groups. The number of carbon atoms (excluding substituents) of the alkyl group is preferably 1 to 20. Specifically, for linear or branched alkyl groups, the number of carbon atoms is preferably 1 to 20, more preferably 1 to 10, and even more preferably 1 to 5. For cyclic alkyl groups, the number of carbon atoms is preferably 4 to 10, and more preferably 5 to 8.

[0058] R 11 Examples of aryl groups include phenyl, biphenyl, naphthyl, anthryl, phenanthryl, pyrenyl, and indenyl groups. Some of the hydrogen atoms in the aryl group may be substituted with alkyl, alkoxy, cyano, halogeno, hydroxyl, or nitro groups. The number of carbon atoms in the aryl group (excluding substituents) is preferably 6 to 20, and more preferably 6 to 12.

[0059] R 11 Examples of aralkyl groups include benzyl, phenethyl, phenylpropyl, phenylbutyl, phenylpentyl, and naphthylmethyl groups. The aryl group contained in the aralkyl group may have some of its hydrogen atoms substituted with alkyl, alkoxy, cyano, halogeno, hydroxyl, or nitro groups. The number of carbon atoms in the aralkyl group (excluding substituents) is preferably 7 to 25, and more preferably 7 to 15.

[0060] R 1 and R2 The amide group is represented by the formula: *-C(=O)-NR 12 R 13 This is represented by, where * represents the bonding site of the ethylene double bond to the carbon atom in formula (2). In the said formula, R 12 R represents a hydrogen atom or an alkyl group. 13 R represents a hydrocarbon group, preferably an alkyl group, acyl group, aryl group, or aralkyl group. 12 and R 13 The alkyl group, R 13 Specific examples of acyl, aryl, and aralkyl groups are shown above in R 11 alkyl groups, aryl groups, aralkyl groups, and R 1 and R 2 The explanation of the acyl group is referenced.

[0061] R 1 and R 2 If both are acyl groups, 1 and R 2 They may be connected to each other to form a ring, and in this case R 1 and R 2 The group formed from this is given by formula: *-C(=O)-R 14 The group represented by -C(=O)-* is shown. In the formula, R 14 R represents a linear or branched alkylene group, and * represents the bonding site to the carbon atom of the ethylene double bond in formula (2). The alkylene group may have some of its hydrogen atoms substituted with aryl groups, alkoxy groups, cyano groups, halogeno groups, hydroxyl groups, nitro groups, etc. 14 The number of carbon atoms in the alkylene group (excluding substituents) is preferably 2 to 10, and more preferably 3 to 8. 1 and R 2 Examples of cyclic groups formed by the linking of acyl groups include the group shown in formula (3-1) below.

[0062] R 1 and R 2 When both are carboxylic acid ester groups, R 1 and R 2 They may be connected to each other to form a ring, and in this case R 1 and R2 The base formed from this is given by the formula: *-C(=O)-OR 15 The group represented by -OC(=O)-* is shown. In the formula, R 15 R represents a linear or branched alkylene group, and * represents the bonding site to the carbon atom of the ethylene double bond in formula (2). The alkylene group may have some of its hydrogen atoms substituted with aryl groups, alkoxy groups, cyano groups, halogeno groups, hydroxyl groups, nitro groups, etc. 15 The number of carbon atoms (excluding substituents) of the alkylene group is preferably 1 to 8, and more preferably 1 to 6. 1 and R 2 Examples of cyclic groups formed by the linking of carboxylic acid ester groups include the group shown in formula (3-2) below.

[0063] R 1 and R 2 When both are amide groups, R 1 and R 2 They may be connected to each other to form a ring, and in this case R 1 and R 2 The group formed from this is given by the formula: *-C(=O)-NR 16 -R 17 -NR 18 The group represented by -C(=O)-* is shown. In the formula, R 16 and R 18 R represents a hydrogen atom or a hydrocarbon group. 17 R represents a linear or branched alkylene group or carbonyl group, and * represents the bonding site to the carbon atom of the ethylene double bond in formula (2). 16 and R 18 Preferred hydrocarbon groups include alkyl groups, aryl groups, or aralkyl groups. 16 and R 18 Specific examples of alkyl, aryl, and aralkyl groups are shown above in R 11 See the explanation of alkyl, aryl, and aralkyl groups. 17 The alkylene group may have some of its hydrogen atoms substituted with aryl groups, alkoxy groups, cyano groups, halogeno groups, hydroxyl groups, nitro groups, etc. 17The number of carbon atoms (excluding substituents) of the alkylene group is preferably 1 to 8, and more preferably 1 to 6. 1 and R 2 Examples of cyclic groups formed by the linkage of amide groups include the groups shown in formulas (3-3) and (3-4) below.

[0064] [ka]

[0065] R 1 The halogenoalkyl group is R as described above. 11 Examples include alkyl groups in which some or all of the hydrogen atoms are replaced by halogen atoms. Examples of halogen atoms include fluorine, chlorine, bromine, and iodine atoms.

[0066] R 2 Examples of hydrocarbon groups include aliphatic hydrocarbon groups and aromatic hydrocarbon groups (aryl groups). Aliphatic hydrocarbon groups may be saturated or unsaturated, and may be linear, branched, or cyclic. A specific example of an aliphatic saturated hydrocarbon group is the above R 11 The explanation of alkyl groups is referenced, and specific examples of aliphatic unsaturated hydrocarbon groups are as described above. 11 Examples include alkyl groups in which some of the carbon-carbon single bonds are replaced by double or triple bonds. Specific examples of aromatic hydrocarbon groups (aryl groups) are the R groups mentioned above. 11 See the explanation regarding the aryl group. 2 An aryl group is preferred as the hydrocarbon group.

[0067] R 2Examples of heteroaryl groups include thienyl group, thiopyranyl group, isothioclomenyl group, pyrrolyl group, imidazolyl group, pyrazolyl group, pyridyl group, pyraridinyl group, pyrimidinyl group, pyridadinyl group, thiazolyl group, isothiazolyl group, furanyl group, and pyranyl group. Preferably, the heteroaryl group has a carbon atom bonded to the carbon atom of the ethylene double bond in formula (2), and more preferably, a carbon atom adjacent to the heteroatom is bonded to the carbon atom of the ethylene double bond in formula (2), which facilitates the synthesis of the compound. The number of carbon atoms in the heteroaryl group is preferably 3 to 18, and more preferably 4 to 12.

[0068] In equation (2), R 2 It is preferable that the group is a hydrogen atom, a cyano group, an acyl group, a carboxyl group, a carboxylic acid ester group, or an amide group, which makes it easier to effectively absorb light in the ultraviolet to violet region. In addition, R is preferred because it makes it easier to effectively absorb light with wavelengths of 380 nm to 430 nm. 2 It is preferable that the group is not a hydrogen atom, but rather a cyano group, acyl group, carboxyl group, carboxylic acid ester group, or amide group.

[0069] In equation (2), R 1 and R 2 Preferably, each of these is independently an acyl group, a carboxyl group, or a carboxylic acid ester group.

[0070] R in equation (2) 3 R represents a hydrogen atom or an alkyl group, and specific examples of alkyl groups are as shown above. 11 See the explanation regarding alkyl groups. 3 The alkyl group preferably has 1 to 3 carbon atoms, and more preferably 1 to 2 carbon atoms. 3 Hydrogen atoms are particularly preferred.

[0071] In group A represented by formula (2), the benzene ring bonded to the ethylene structure functions to donate electrons to the ethylene structure together with the sulfur atom bonded to the benzene ring.4 R represents a hydrogen atom, an organic group, or a polar functional group, and multiple R 4 They may be the same or different from one another.

[0072] R in equation (2) 4 Examples of organic groups include alkyl groups, alkoxy groups, alkylthio groups, alkoxycarbonyl groups, alkylsulfonyl groups, alkylsulfinyl groups, aryl groups, aralkyl groups, aryloxy groups, arylthio groups, aryloxycarbonyl groups, arylsulfonyl groups, arylsulfinyl groups, heteroaryl groups, amino groups, amide groups, sulfonamide groups, carboxyl groups (carboxylic acid groups), cyano groups, etc. 4 Examples of polar functional groups include halogen groups, hydroxyl groups, nitro groups, and sulfo groups (sulfonic acid groups).

[0073] R 4 A specific example of the alkyl group is the above R 11 See the explanation regarding alkyl groups. 4 The alkyl group may have substituents, and examples of substituents on the alkyl group include aryl groups, heteroaryl groups, halogeno groups, hydroxyl groups, carboxyl groups, alkoxy groups, cyano groups, nitro groups, amino groups, sulfo groups, and the like.

[0074] R 4 Specific examples of alkyl groups included in the alkoxy group, alkylthio group, alkoxycarbonyl group, alkylsulfonyl group, and alkylsulfinyl group are R 4 See the explanation regarding alkyl groups.

[0075] R 4 Specific examples of aryl and aralkyl groups are shown above in R 11 See the explanation of aryl and aralkyl groups. 4The aryl group or aralkyl group may have substituents, and examples of such substituents include alkyl groups, alkoxy groups, heteroaryl groups, halogeno groups, halogenoalkyl groups, hydroxyl groups, cyano groups, nitro groups, amino groups, thiocyanate groups, acyl groups, alkoxycarbonyl groups, aryloxycarbonyl groups, carbamoyl groups, sulfo groups, alkylsulfinyl groups, arylsulfinyl groups, alkylsulfonyl groups, arylsulfonyl groups, sulfamoyl groups, and the like.

[0076] R 4 Specific examples of aryl groups included in the aryloxy, arylthio, aryloxycarbonyl, arylsulfonyl, and arylsulfinyl groups are R 4 See the explanation regarding the aryl group.

[0077] R 4 A specific example of the heteroaryl group is the above R 2 See the explanation regarding heteroaryl groups. Heteroaryl groups may have substituents, and examples of substituents on heteroaryl groups include alkyl groups, alkoxy groups, aryl groups, halogeno groups, halogenoalkyl groups, hydroxyl groups, cyano groups, amino groups, nitro groups, thiocyanate groups, acyl groups, alkoxycarbonyl groups, aryloxycarbonyl groups, carbamoyl groups, sulfo groups, alkylsulfinyl groups, arylsulfinyl groups, alkylsulfonyl groups, arylsulfonyl groups, sulfamoyl groups, and the like.

[0078] R 4 The amino group is given by formula: -NR 21 R 22 It is represented as R 21 and R 22Examples include those in which each is independently a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, an aralkyl group, or a heteroaryl group. Specific examples of alkyl groups, aryl groups, aralkyl groups, and heteroaryl groups are given in the above explanation. Alkenyl groups and alkynyl groups include substituents in which some of the carbon-carbon single bonds of the alkyl group described above are replaced by double or triple bonds, and in these substituents, some of the hydrogen atoms may be substituted by halogen atoms. Also, R 21 and R 22 They may be connected to each other to form a ring.

[0079] R 4 The amide group is given by formula: -NH-C(=O)-R 23 It is represented as R 23 Examples include alkyl groups, aryl groups, aralkyl groups, and heteroaryl groups. Specific examples of alkyl groups, aryl groups, aralkyl groups, and heteroaryl groups can be found in the explanation above, and some of the hydrogen atoms may be substituted with halogen atoms.

[0080] R 4 The sulfonamide group is of the formula: -NH-SO2-R 24 It is represented as R 24 Examples include alkyl groups, aryl groups, aralkyl groups, and heteroaryl groups. Specific examples of alkyl groups, aryl groups, aralkyl groups, and heteroaryl groups can be found in the explanation above, and some of the hydrogen atoms may be substituted with halogen atoms.

[0081] R 4 Examples of halogen groups include fluoro groups, chloro groups, bromo groups, and iodine groups.

[0082] R 4Preferably, the group is one or more selected from a hydrogen atom, an alkyl group, an alkoxy group, an alkylthio group, an aralkyl group, an aryloxy group, and an arylthio group. From the viewpoint of enabling the compound represented by formula (1) to stably absorb light in the ultraviolet to violet region and to effectively absorb light with wavelengths of 380 nm to 430 nm, R 4 The R atoms are preferably hydrogen atoms or alkyl groups, and the alkyl group is preferably having 1 to 4 carbon atoms, and more preferably 1 to 3 carbon atoms. In particular, the four R atoms bonded to the benzene ring of group A in formula (2) 4 Preferably, two or more of these are hydrogen atoms, more preferably three or more are hydrogen atoms, and particularly preferably all four are hydrogen atoms.

[0083] In group A represented by formula (2), the sulfur atom may be bonded to the ortho position, the meta position, or the para position relative to the ethylene structure. However, from the viewpoint of ease of production of the compound represented by formula (1), it is preferable that the sulfur atom is bonded to the para position relative to the ethylene structure.

[0084] In formula (1), two or more groups A are bonded to the linking group L. By bonding two or more groups A to the linking group L, the heat resistance of the compound represented by formula (1) can be increased. The two or more groups A bonded to the linking group L may be the same or different. The number a of groups A bonded to the linking group L in formula (1) is preferably 8 or less, more preferably 6 or less, and even more preferably 4 or less. From the viewpoint of easily producing a highly stable compound represented by formula (1), a is more preferably 3 or less, and particularly preferably 2.

[0085] Examples of linking groups L include alkylene groups, arylene groups, heteroarylene groups, divalent linking groups such as -O-, -CO-, -S-, -SO-, -SO2-, and -NH-; trivalent linking groups such as methine groups (-C<) and -N< which may have alkyl groups; tetravalent linking groups such as >C<; and linking groups combining these. The alkylene group may be linear, branched, or cyclic. Furthermore, the alkylene group and arylene group may have a hydroxyl group and / or a thiol group.

[0086] Examples of linking groups L include those shown in formulas (4-1) to (4-17) below. In formulas (4-1) to (4-17), * represents the bonding site of group A. Two groups A are bonded to the linking group L in formulas (4-1) to (4-9), three groups A are bonded to the linking group L in formulas (4-10) to (4-13), four groups A are bonded to the linking group L in formulas (4-14) to (4-15), five groups A are bonded to the linking group L in formula (4-16), and six groups A are bonded to the linking group L in formula (4-17).

[0087] [ka]

[0088] From the viewpoint of improving the stability of the compound represented by formula (1), the linking group L is preferably an alkylene group in which some of the hydrogen atoms may be replaced by hydroxyl groups and / or thiol groups, an arylene group in which some of the hydrogen atoms may be replaced by hydroxyl groups and / or thiol groups, -O-, -S-, and linking groups that combine these groups (however, ether bonds and thioether bonds are not continuous). Furthermore, the number of carbon atoms (number of consecutive carbon atoms) of a linear or branched alkylene group is preferably 6 or less, more preferably 4 or less, and even more preferably 3 or less. For a cyclic alkylene group, the number of carbon atoms is preferably 4 or more, more preferably 5 or more, preferably 10 or less, and even more preferably 8 or less. The number of carbon atoms of an arylene group is preferably 5 or more, more preferably 6 or more, preferably 10 or less, and even more preferably 8 or less. The linking group L is particularly preferably the group shown in formula (4-6).

[0089] As a compound represented by formula (1), the compound represented by the following formula (5) is particularly preferred. Such a compound has, for example, a peak with an absorption maximum in the wavelength range of 300 nm to 420 nm, can effectively absorb light with a wavelength of 380 nm to 430 nm, and is also highly stable and easy to manufacture. In the following formula (5), R 1x and R 1y The explanation is in the above R 1 The explanation of R is referenced. 2x and R 2y The explanation is in the above R 2 The explanation of R is referenced. 3x and R 3y The explanation is in the above R 3 The explanation is referenced.

[0090] [ka]

[0091] Furthermore, examples of the sulfur atom-containing ultraviolet absorber of the present invention include compounds represented by the following formula (I).

[0092] [ka] [In formula (I), R A1 and R A3 Each of these independently represents an organic group, R A2 R represents a hydrogen atom, an organic group, or a polar functional group, and multiple R A2 They may be identical or different from one another.

[0093] R in equation (I) A1 , R A2 , and R A3 A specific example of the organic group is R in formula (2) above. 4 See the explanation regarding the organic group.

[0094] R A1 As such, an aryl group is preferred, and an aryl group having a substituent is more preferred.A1 The number of carbon atoms (excluding substituents) in the aryl group is preferably 6 to 12, and more preferably 6 to 10. A1 If the aryl group has substituents, the substituents are preferably alkyl groups or hydroxyl groups, and the alkyl group as a substituent may have some of its hydrogen atoms replaced by alkoxy groups, aryl groups, hydroxyl groups, or carboxylic acid ester groups. The number of carbon atoms (excluding substituents) of the alkyl group is preferably 1 to 20, more preferably 1 to 15, even more preferably 1 to 10, and still more preferably 1 to 8. A1 When the aryl group has substituents, it is preferable that it has one or more hydroxyl groups as substituents, and more preferably a group represented by the following formula (IA1). [ka] [In formula (IA1), R A11 and R A12 represents a hydrogen atom or an alkyl group, * represents the bonding site to the nitrogen atom in formula (I).

[0095] R A11 and R A12 A specific example of the alkyl group is the above R 11 See the explanation regarding alkyl groups. A11 and R A12 The alkyl group is preferably a linear alkyl group having 1 to 8 carbon atoms or a branched alkyl group having 3 to 10 carbon atoms.

[0096] R A3 The group is preferably an alkyl group, an aryl group, an aralkyl group, or a heteroaryl group, more preferably an alkyl group or an aryl group, and even more preferably an alkyl group. A3 The number of carbon atoms (excluding substituents) of the alkyl group is preferably 1 to 18, and more preferably 3 to 12. A3 The alkyl group is preferably linear.

[0097] R A2 A specific example of a polar functional group is R in formula (2) above.4 See the explanation regarding polar functional groups.

[0098] R A2 Preferably, it is a hydrogen atom, and in particular, the three R atoms in formula (IA1) A2 Preferably, two or more of these are hydrogen atoms, and more preferably, all three are hydrogen atoms.

[0099] As an ultraviolet absorber containing a sulfur atom, the compound represented by formula (1) or the compound represented by formula (I) is preferred, and the compound represented by formula (1) is more preferred.

[0100] UV absorbers containing sulfur atoms preferably have a maximum absorption peak at a wavelength of 420 nm or less in the absorption spectrum measured in toluene in the wavelength range of 300 nm to 600 nm (preferably in the range of 300 nm to 700 nm, and more preferably in the range of 300 nm to 800 nm). That is, when the absorption spectrum of a UV absorber containing sulfur atoms is measured in toluene, it is preferable that the peak has an absorption maximum in the wavelength range of 300 nm to 420 nm, and that the absorption maximum of this absorption peak takes its maximum value in the wavelength range of 300 nm to 600 nm. Compounds exhibiting such an absorption spectrum can effectively absorb light in the ultraviolet to violet region. The maximum wavelength of the absorption peak is more preferably 310 nm or more, even more preferably 315 nm or more, even more preferably 410 nm or less, and even more preferably 405 nm or less.

[0101] The ultraviolet absorber containing sulfur atoms preferably has a peak width of 100 nm or less, more preferably 80 nm or less, and even more preferably 70 nm or less, when the absorbance at the maximum wavelength of the maximum absorption peak is set to 1. If the compound exhibits such an absorption spectrum, it will be able to selectively absorb light in the ultraviolet to violet region. The lower limit of the peak width is not particularly limited, but for example, it may be 20 nm or more, or 30 nm or more.

[0102] The ultraviolet absorber containing sulfur atoms preferably has an absorbance of 0.1 or higher, and more preferably 0.15 or higher, at a wavelength of 400 nm, when the absorbance at the maximum wavelength of the maximum absorption peak is set to 1. If the ultraviolet absorber containing sulfur atoms exhibits such an absorption spectrum, it can effectively absorb light at wavelengths of 380 nm to 430 nm.

[0103] The ultraviolet absorber containing sulfur atoms preferably has an average absorbance of 0.03 or less in the wavelength range of 470 nm to 600 nm (preferably in the wavelength range of 450 nm to 700 nm), more preferably 0.02 or less, and even more preferably 0.01 or less, when the absorbance at the maximum wavelength of the maximum absorption peak is set to 1. Exhibiting such an absorption spectrum can increase light transmittance over a wide range of the visible light region.

[0104] The absorption spectrum is determined by measuring absorbance at 1 nm intervals within a predetermined wavelength range. Absorbance values ​​at wavelengths smaller than 1 nm are calculated by linear interpolation from the absorbance measurements at 1 nm intervals. The concentration of the UV absorber in toluene is adjusted so that the absorbance at the absorption maximum of the maximum absorption peak is 1 ± 0.003. The average absorbance in the wavelength range of 470 nm to 600 nm is determined by averaging the absorbance values ​​of 131 points measured at 1 nm intervals within the wavelength range of 470 nm to 600 nm.

[0105] The ultraviolet absorber containing a sulfur atom may be a benzotriazole derivative, benzophenone derivative, benzooxazinon derivative, triazine derivative, etc.

[0106] The dope may contain only one or more types of ultraviolet absorbers that contain sulfur atoms.

[0107] With the sulfur atom-containing ultraviolet absorber of the present invention, even if the amount of ultraviolet absorber in the dope is 6 parts by mass or less per 100 parts by mass of (meth)acrylic polymer, it is possible to form a film with excellent light transmission suppression properties at wavelengths of 380 nm to 430 nm (especially at 400 nm) by solution film formation. Furthermore, because the amount of ultraviolet absorber in the dope is low (6 parts by mass or less), the ultraviolet absorber does not bleed out during film formation, and internal haze is reduced, thus preventing defects in the appearance of the film and contamination of the molding equipment (film rolls, etc.).

[0108] 1.3 Solvents The dope of the present invention preferably contains a solvent. In the dope of the present invention, the (meth)acrylic polymer having a ring structure in its main chain and the ultraviolet absorber containing a sulfur atom are preferably dissolved or dispersed in the solvent.

[0109] The solvent included in the dope is not particularly limited as long as it is a solvent that can dissolve or disperse the (meth)acrylic polymer having a ring structure in its main chain and the ultraviolet absorber containing sulfur atoms. Either a chlorinated organic solvent or a non-chlorinated solvent can be used, but it is preferable to use a chlorinated organic solvent because of its excellent solubility for the (meth)acrylic polymer. The solvent may consist of only one type or two or more types. When using a chlorinated organic solvent and a non-chlorinated solvent, the content of the chlorinated organic solvent in the total amount of solvent is preferably 50% by mass or more, more preferably 70% by mass or more, and there is no particular upper limit, but it may be 99% by mass or less.

[0110] Examples of chlorinated organic solvents include dichloroethane, methylene chloride, and chloroform, with methylene chloride being particularly preferred. Examples of non-chlorinated organic solvents include methanol, ethanol, n-propanol, isopropanol, n-butanol, s-butanol, t-butanol, methyl acetate, ethyl acetate, amyl acetate, acetone, methyl ethyl ketone, methyl isobutyl ketone, tetrahydrofuran, 1,3-dioxolane, 1,4-dioxane, cyclohexanone, ethyl formate, 2,2,2-trifluoroethanol, 2,2,3,3-hexafluoro-1-propanol, 1,3-difluoro-2-propanol, 1,1,1,3,3,3-hexafluoro-2-methyl-2-propanol, 1,1,1,3,3,3-hexafluoro-2-propanol, 2,2,3,3,3-pentafluoro-1-propanol, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, γ-butyrolactone, and nitroethane.

[0111] The content of the (meth)acrylic polymer having a ring structure in the main chain in the dope is not particularly limited and can be determined by considering the solubility and dispersibility of the (meth)acrylic polymer in the solvent used, as well as the film formation conditions, etc., but is preferably 3% by mass or more and 40% by mass or less, more preferably 5% by mass or more and 38% by mass or less, and even more preferably 8% by mass or more and 35% by mass or less.

[0112] The amount of ultraviolet absorber containing sulfur atoms in the dope is preferably in the range of 0.5 parts by mass to 6 parts by mass, more preferably 0.8 parts by mass to 5.0 parts by mass, and even more preferably 1.0 part by mass to 4.5 parts by mass, per 100 parts by mass of a (meth)acrylic polymer having a ring structure in its main chain, in order to exhibit the desired performance.

[0113] 1.4 Other Additives The dope of the present invention may contain various additives, as long as they do not impair the effects of the present invention. Examples of additives include known ultraviolet absorbers other than the above-mentioned sulfur atom-containing ultraviolet absorbers; phenolic antioxidants (e.g., hydroquinone, 2,6-di-t-butyl-p-cresol, tocopherol, 1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene, etc.); phosphorus-based antioxidants (e.g., triphenyl phosphite, tris(2,4-di-t-butylphenyl) phosphite, etc.); sulfur-based antioxidants (e.g., 2-mercaptobenzimidazole, dilauryl 3,3'-thiodipropionate) Antioxidants such as (etc.); stabilizers such as light stabilizers, weather stabilizers, and heat stabilizers; reinforcing materials such as glass fibers and carbon fibers; near-infrared absorbers; flame retardants such as tris(dibromopropyl) phosphate, triallyl phosphate, and antimony oxide; phase difference adjusters such as phase difference enhancers, phase difference reducers, and phase difference stabilizers; antistatic agents including anionic, cationic, and nonionic surfactants; compatibilizers; stabilizers; colorants such as inorganic pigments, organic pigments, and dyes; organic and inorganic fillers (for example, inorganic particles such as silicon dioxide, zirconium oxide, and titanium dioxide); resin modifiers; and so on. The content of each additive in the dope is preferably in the range of 0 to 5 parts by mass, more preferably 0 to 2 parts by mass, and even more preferably 0 to 1 part by mass, per 100 parts by mass of a (meth)acrylic polymer having a ring structure in the main chain.

[0114] Other ultraviolet absorbers besides those containing sulfur atoms (hereinafter also referred to as "other ultraviolet absorbers") may be any known ultraviolet absorbers that do not contain sulfur atoms, such as benzophenone compounds, salicylate compounds, benzoate compounds, triazole compounds, and triazine compounds. Examples of benzophenone compounds include 2,4-dihydroxybenzophenone, 4-n-octyloxy-2-hydroxybenzophenone, and 2,2'-dihydroxy-4,4'-dimethoxybenzophenone. Examples of salicylate compounds include pt-butylphenyl salicylate. Examples of benzoate compounds include 2,4-di-t-butylphenyl-3',5'-di-t-butyl-4'-hydroxybenzoate. Examples of triazole compounds include 2,2'-methylenebis[4-(1,1,3,3-tetramethylbutyl)-6-(2H-benzotriazole-2-yl)phenol], 2-(3,5-di-tert-butyl-2-hydroxyphenyl)-5-chlorobenzotriazole, 2-(2H-benzotriazole-2-yl)-p-cresol, 2-(2H-benzotriazole-2-yl)-4,6-bis(1-methyl-1-phenylethyl)phenol, 2-benzotriazole-2-yl-4,6-di-tert-butylphenol, 2-[5-chloro(2H)-benzotriazole-2-yl]-4-methyl-6-t-butylphenol, 2-(2H-benzotriazole-2-yl)-4,6-di-t-butylphenol, and 2-(2H-benzotriazole-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol. Examples of triazine compounds include 2-[4,6-bis(biphenyl-4-yl)-1,3,6-triazi-2-yl]-5-[(2-ethylhexyl)oxy]phenol, 2-mono(hydroxyphenyl)-1,3,5-triazine compounds, 2,4-bis(hydroxyphenyl)-1,3,5-triazine compounds, and 2,4,6-tris(hydroxyphenyl)-1,3,5-triazine compounds. Other commercially available UV absorbers include, for example, the triazine-based UV absorbers Chinuvin® 1577, Chinuvin® 460, Chinuvin® 477 (manufactured by BASF Japan), Adekastab® LA-F70 (manufactured by ADEKA), and the triazole-based UV absorber Adekastab® LA-31 (manufactured by ADEKA). Other UV absorbers may be used individually or in combination of two or more types.

[0115] If other UV absorbers are included, the ratio of the sulfur atom-containing UV absorber to the other UV absorbers (sulfur atom-containing UV absorber: other UV absorbers) is preferably 1:0.01 to 1:1, and more preferably 1:0.05 to 1:0.8.

[0116] 1.5 Preparation of Dope The dope of the present invention can be prepared by dissolving or dispersing a (meth)acrylic polymer having a ring structure in its main chain, an ultraviolet absorber containing sulfur atoms, and optionally other polymers and additives in a solvent. Conventional known methods can be widely applied as methods for dissolving or dispersing in the solvent. For example, the (meth)acrylic polymer having a ring structure in its main chain, the ultraviolet absorber containing sulfur atoms, and optionally other polymers and additives may be added to the solvent and mixed by appropriate shearing and / or stirring. The order of addition to the solvent is not particularly limited; the (meth)acrylic polymer having a ring structure in its main chain, the ultraviolet absorber containing sulfur atoms, and optionally other polymers and additives may all be added simultaneously or sequentially. Alternatively, the (meth)acrylic polymer having a ring structure in its main chain, the ultraviolet absorber containing sulfur atoms, and optionally other polymers and additives may be pre-mixed, preferably by heating and melting, and then melt-kneaded by applying appropriate shearing force to produce a resin composition (e.g., a pelletized or powdered resin composition). The dope can then be prepared by mixing this resin composition with the solvent. These mixing steps can be carried out by appropriately adjusting the temperature and pressure. Furthermore, after the above mixing steps, the resulting dope may be filtered or degassed.

[0117] 1.5 Characteristics of Dope The dope of the present invention preferably has a viscosity of 0.1 Pa·s to 50 Pa·s at 25°C, more preferably 0.3 Pa·s to 40 Pa·s, and even more preferably 0.4 Pa·s to 30 Pa·s. Within this viscosity range, a uniform film can be easily formed in the solution film formation method.

[0118] The dope of the present invention preferably has a haze of 20% or less, more preferably 15% or less, and even more preferably 10% or less. There is no particular lower limit, but it may be 0%. Within the above haze range, it is possible to form a highly transparent film, and therefore it is suitably used in optical components and the like where light transmittance is required. The haze of the dope is a value calculated by the method described in the examples below.

[0119] The dope of the present invention preferably has a solid content concentration of 3% by mass or more and 40% by mass or less, more preferably 5% by mass or more and 38% by mass or less, and even more preferably 8% by mass or more and 35% by mass or less. Within the above solid content concentration range, a uniform film can be formed in the solution film formation method.

[0120] The dope of the present invention preferably exhibits the following characteristics when a film (for example, a film with a thickness of 20 μm) is formed by a solution film formation method: the film has a light transmittance of 15% or less at a wavelength of 400 nm, an in-plane phase difference Re for light at a wavelength of 589 nm of 10 nm or less, and an absolute value of the thickness-direction phase difference Rth for light at a wavelength of 589 nm of 20 nm or less.

[0121] 2. Film The film of the present invention comprises a (meth)acrylic polymer having a ring structure in its main chain and an ultraviolet absorber, and is characterized by having a light transmittance of 15% or less at a wavelength of 400 nm, an in-plane phase difference Re for light at a wavelength of 589 nm of 10 nm or less, and an absolute value of the thickness-direction phase difference Rth for light at a wavelength of 589 nm of 20 nm or less. The film of the present invention is preferably formed by a solution film-forming method using the above dope. Specific examples and preferred embodiments of the (meth)acrylic polymer having a ring structure in the main chain contained in the film of the present invention are the same as the specific examples and preferred embodiments of the (meth)acrylic polymer contained in the dope described above. The ultraviolet absorber contained in the film of the present invention preferably contains an ultraviolet absorber containing sulfur atoms. Specific examples and preferred embodiments of the ultraviolet absorber containing sulfur atoms are the same as those of the ultraviolet absorber containing sulfur atoms contained in the dope described above. Furthermore, the film of the present invention may also contain other polymers and additives that may be contained in the dope, and specific examples and preferred embodiments thereof are the same as the specific examples and preferred embodiments of other polymers and other additives that may be contained in the dope.

[0122] The amount of ultraviolet absorber in the film of the present invention is preferably 0.5 parts by mass to 6 parts by mass, more preferably 0.8 parts by mass to 5.0 parts by mass, and even more preferably 1.0 part by mass to 4.5 parts by mass, per 100 parts by mass of a (meth)acrylic polymer having a ring structure in its main chain. Furthermore, when the ultraviolet absorber contains both an ultraviolet absorber containing sulfur atoms and other ultraviolet absorbers, the content ratio of the sulfur atom-containing ultraviolet absorber to the other ultraviolet absorbers (sulfur atom-containing ultraviolet absorber: other ultraviolet absorbers) is preferably 1:0.01 to 1:1, and more preferably 1:0.05 to 1:0.8. The content of other polymers in the film of the present invention is preferably 100 parts by mass or less, more preferably 40 parts by mass or less, even more preferably 10 parts by mass or less, even more preferably 5 parts by mass or less, or even 0 parts by mass, per 100 parts by mass of the (meth)acrylic polymer having a ring structure in its main chain. The content of other additives in the film of the present invention is preferably 0 to 5 parts by mass, more preferably 0 to 2 parts by mass, and even more preferably 0 to 1 part by mass, per 100 parts by mass of the (meth)acrylic polymer having a ring structure in its main chain.

[0123] 2.1 Film manufacturing method The film of the present invention is formed, for example, by a solution film formation method using the dope described above. Specifically, it can be produced by casting or coating the dope onto a support, then drying and evaporating the solvent. When high-level control of optical properties is required, it is preferable to perform the operation in a clean booth or similar environment.

[0124] Embodiments of the solution film formation method are described below, but are not limited to those described below.

[0125] First, dope (for example, liquid temperature between -20°C and 50°C) is delivered by a liquid delivery pump or the like, and then cast or coated onto the surface of a support such as a plate, sheet, belt, or drum made of metal or synthetic resin using a bar coater, T-die, bar-type T-die, die coat, etc., to form a dope film.

[0126] Next, the formed doped film is heated on the support to evaporate and remove the solvent, thereby forming a film. The conditions for evaporating the solvent can be appropriately determined depending on the glass transition temperature of the (meth)acrylic polymer and the type of solvent used, but from the viewpoint of suppressing foaming, the drying temperature immediately after casting or coating is preferably 30°C to 110°C, and it is preferable to gradually increase the temperature according to the amount of residual solvent. The drying time is preferably 1 minute to 60 minutes. The drying method is not particularly limited as long as it is possible to evaporate and remove the solvent at the above temperature, and for example, an oven, drying furnace, hot plate, infrared heating, etc. can be used. Furthermore, from the viewpoint of suppressing condensation on the film surface, it is preferable to dry in dehumidified air, but it is not preferable to blow hot air or the like directly onto the coating liquid surface before the coating liquid surface hardens, as this will worsen the surface shape.

[0127] Then, the formed film is peeled off the support surface. The obtained film may be subjected to drying, heating, stretching, etc., as appropriate. When performing the drying and / or heating process, it is preferable to apply appropriate tension to the film by fixing it to a frame or similar means to prevent uneven drying and / or heating in the film and subsequent distortion of the film. Further drying and / or heating of the film can reduce residual solvent. For industrial continuous production, it is preferable to dry the film by gripping both ends in the width direction with a tenter and, if necessary, adjusting the expansion and contraction according to the slack in the film or shrinkage due to drying, or by passing the film alternately through a number of rolls arranged vertically in an oven (vertical pass method). The tenter method and / or vertical pass method should be appropriately selected according to the amount of residual solvent in the film peeled from the support surface, and both methods may be performed, or each method may be performed multiple times. Furthermore, it is preferable to perform a stretching process from the viewpoint of improving the mechanical strength of the film and improving the accuracy of the film thickness.

[0128] The film may be stretched after the unstretched film has been formed and then stored, or it may be stretched continuously immediately after the unstretched film has been formed. The stretched film may be either uniaxially oriented or biaxially oriented, but biaxially oriented film is more preferred. In the case of biaxial stretching, the film is stretched in two orthogonal directions, which improves the mechanical strength in any direction within the film plane. It also reduces the in-plane phase difference of the film, making it easier to obtain a film with high optical isotropy. The film can be stretched using any conventionally known stretching method. Specifically, examples include longitudinal stretching using rolls or a hot air furnace, transverse stretching using a tenter, and stretching that combines these methods sequentially. Alternatively, a simultaneous biaxial stretching method that stretches both longitudinally and transversely at the same time is also acceptable, as is a sequential biaxial stretching method that performs longitudinal stretching with a roll followed by transverse stretching with a tenter.

[0129] The stretching temperature of the film can be appropriately determined within a range that does not impair the effects of the present invention. The stretching temperature is preferably in the range of Tg or more and Tg+30°C or less, where Tg is the glass transition temperature of the film determined by the DSC method.

[0130] The stretching ratios for the longitudinal and transverse stretching of the film can be appropriately determined within a range that does not impair the effects of the present invention. For example, the stretching ratios are preferably about 1.1 to 8.0 times in the longitudinal direction and about 1.2 to 6.0 times in the transverse direction perpendicular to the longitudinal direction, respectively.

[0131] 2.2 Characteristics of Film From the viewpoint of mechanical strength, the thickness of the film of the present invention is preferably 5 μm or more, more preferably 10 μm or more, and even more preferably 15 μm or more. On the other hand, from the viewpoint of thinning the film, the film thickness is preferably 200 μm or less, more preferably 150 μm or less, and even more preferably 100 μm or less. The film thickness can be measured, for example, using a Mitutoyo Digital Micrometer.

[0132] The film of the present invention preferably has a light transmittance of 15% or less at a wavelength of 400 nm. More preferably, the light transmittance at a wavelength of 400 nm is 14% or less, and even more preferably 13% or less. Having a light transmittance at a wavelength of 400 nm within the above range makes it particularly suitable for use in organic EL display devices.

[0133] The film of the present invention preferably has an in-plane phase difference (Re) of 10 nm or less with respect to light with a wavelength of 589 nm, more preferably 7 nm or less, even more preferably 5 nm or less, and even more preferably 3 nm or less. Furthermore, the absolute value of the thickness-direction phase difference (Rth) with respect to light with a wavelength of 589 nm is preferably 20 nm or less, more preferably 15 nm or less, and even more preferably 10 nm or less. A film having such a phase difference can be suitably used as a polarizer protective film for a polarizer plate of a display device. On the other hand, if the absolute value of the in-plane phase difference of the film exceeds 10 nm, or the absolute value of the thickness-direction phase difference exceeds 20 nm, problems such as a decrease in contrast may occur in the display device when used as a polarizer protective film for a polarizer plate of a display device.

[0134] Phase difference is an index value calculated based on birefringence, and the in-plane phase difference (Re) and the thickness-direction phase difference (Rth) can be calculated using the following formulas, respectively. In an ideal film that is perfectly optically isotropic in three dimensions, both the in-plane phase difference Re and the thickness-direction phase difference Rth are 0. Re=(nx-ny)×d Rth = ((nx + ny) / 2 - nz) × d In the above formula, nx represents the refractive index in the slow axis direction within the plane of the film, ny represents the refractive index in the fast axis direction within the plane of the film, nz represents the refractive index in the thickness direction of the film, and d represents the film thickness.

[0135] The film of the present invention preferably has a total light transmittance of 85% or more, more preferably 88% or more, even more preferably 90% or more, and even more preferably 92% or more. If the total light transmittance is within the above range, it has high transparency and can be suitably used in optical components and the like where light transmission is required.

[0136] The film of the present invention preferably has a glass transition temperature of 110°C or higher, more preferably 115°C or higher, and even more preferably 120°C or higher. If the glass transition temperature is within the above range, a film with excellent heat resistance can be obtained.

[0137] The film of the present invention preferably has an internal haze of 2.0% or less per 100 μm thickness, more preferably 1.0% or less, even more preferably 0.5% or less, and even more preferably 0.3% or less. If the internal haze is within the above range, it has high transparency and can be suitably used in optical components and the like where light transmittance is required. The internal haze may also be measured or calculated by the method described in the examples below.

[0138] 2.3 Uses of film The applications of the film of the present invention are not particularly limited and can be used in various applications (for example, as an optical film such as a protective film, phase difference film, viewing angle compensation film, light diffusion film, reflective film, anti-reflective film, anti-glare film, brightness enhancement film, conductive film for touch panels, or for the interior and exterior of automobiles and various devices, or as a decorative film, etc.). However, because it has heat resistance and transparency, and is excellent in suppressing light transmission at specific wavelengths (preferably 380 nm to 430 nm, especially 400 nm), or has a low phase difference, it can be suitably used as an optical film for organic EL display devices. By having excellent light transmission suppression at specific wavelengths, it is possible to suppress the degradation of organic EL elements in the display device.

[0139] The organic EL display device of the present invention includes the above-mentioned film, and by including this film, the degradation of the organic EL element is suppressed while maintaining excellent optical properties. [Examples]

[0140] The present invention will be described in more detail below with reference to examples, but the present invention is not limited by the following examples, and it is certainly possible to implement it with appropriate modifications within the scope that is consistent with the spirit of the preceding and following descriptions, and all such modifications are included within the technical scope of the present invention. In the following, unless otherwise specified, "parts" means "parts by mass" and "%" means "percent mass".

[0141] First, the measurement methods used in the following manufacturing examples, case studies, and comparative examples will be explained. (1) Weight average molecular weight, number average molecular weight The weight-average molecular weight (Mw) and number-average molecular weight (Mn) of the polymer were determined using gel permeation chromatography (GPC) and converted to polystyrene equivalent. The equipment and measurement conditions used are as follows. System: Tosoh GPC system HLC-8220 Measurement column configuration: • Guard column (manufactured by Tosoh, TSKguardcolumn SuperHZ-L) • Separation columns (Tosoh Corporation, TSKgel SuperHZM-M) - 2 columns connected in series Reference side column configuration: • Reference column (Tosoh Corporation, TSKgel SuperH-RC) Developing solvent: Chloroform (manufactured by Wako Pure Chemical Industries, special grade) Flow rate of developing solvent: 0.6 mL / min Standard sample: TSK standard polystyrene (manufactured by Tosoh, PS-oligomer kit) Column temperature: 40℃

[0142] (2) Glass transition temperature (Tg) of polymers The glass transition temperature of the polymer was determined in accordance with JIS K 7121. Specifically, a differential scanning calorimeter (Rigaku Thermo plus EVO DSC-8230) was used to evaluate the temperature from the starting point method by heating approximately 10 mg of the sample from room temperature to 200°C (heating rate 20°C / min) under a nitrogen gas atmosphere, and obtaining the DSC curve. Alpha-alumina was used as the reference.

[0143] (3) Dope Haze The haze of the doped material was measured using a haze meter (NDH-1001DP, manufactured by Nippon Denshoku Industries Co., Ltd.) with a quartz cell having a path length of 10 mm. Specifically, standard calibration was performed using an empty quartz cell, and then the haze of the doped material was measured.

[0144] (4) Viscosity of the dope The viscosity of the dope was measured at 25°C using a BHII type viscometer (manufactured by Toki Sangyo Co., Ltd.).

[0145] (5) Internal haze of the film The internal haze of the film was determined in accordance with the provisions of JIS K7136. Specifically, a haze meter (NDH-1001DP, manufactured by Nippon Denshoku Industries Co., Ltd.) was used to measure the internal haze value per 100 μm of thickness by filling a quartz cell with 1,2,3,4-tetrahydronaphthalene (tetralin) and immersing the prepared film in it.

[0146] (6) Film thickness The film thickness was determined using a digital micrometer (manufactured by Mitutoyo Corporation).

[0147] (7) Light transmittance of the film The light transmittance of the film was evaluated by measuring the transmittance for each wavelength of light using a spectrophotometer (Shimadzu Corporation, UV-3600).

[0148] (8) Phase difference of film The in-plane phase difference Re and the thickness-direction phase difference Rth of the film with respect to light with a wavelength of 589 nm were measured using a fully automatic birefringent (KOBRA-WR, manufactured by Oji Instruments Co., Ltd.) under the condition of an incident angle of 40°. Specifically, the in-plane phase difference Re and the thickness-direction phase difference Rth were calculated from the following formulas, with nx being the refractive index in the slow phase axis direction of the film, ny being the refractive index in the fast phase axis direction of the film, nz being the refractive index in the thickness direction of the film, and d being the thickness of the film. In-plane phase difference Re=|nx-ny|×d Thickness-direction phase difference Rth = [(nx + ny) / 2 - nz] × d

[0149] In the following manufacturing example, methyl methacrylate (MMA), α-methylene-γ-butyrolactone (ML), and methyl ethyl ketone (MEK) were obtained from Tokyo Chemical Industry Co., Ltd. Perloyl L (dilauroyl peroxide, LPO) was obtained from NOF Corporation. Polyoxyethylene distyrylphenyl ether sulfate ammonium (Hythenol® NF-08) was obtained from Daiichi Kogyo Seiyaku Co., Ltd.

[0150] Manufacturing Example 1 In a reaction vessel equipped with a stirrer, temperature sensor, condenser, and nitrogen inlet, 229.6 parts of methyl methacrylate (MMA), 33 parts of methyl 2-(hydroxymethyl)acrylate (MHMA), 0.138 parts of antioxidant (ADEKA's "ADEKA Stab® 2112"), 248.6 parts of toluene as a solvent, and 0.1925 parts of n-dodecyl mercaptan (nDM) were charged, and the mixture was heated to 105°C while nitrogen was passed through it. As reflux began due to the rising temperature, 0.2838 parts of t-amyl peroxyisononanoate (Luperox® 570, manufactured by Arkema Yoshitomi Co., Ltd.) were added as a polymerization initiator. Simultaneously, 0.5646 parts of the same t-amyl peroxyisononanoate and 12.375 parts of styrene (St) were added dropwise over 2 hours while solution polymerization proceeded under reflux at approximately 105-110°C. After the dropwise addition was complete, the mixture was aged for a further 4 hours at the same temperature.

[0151] Next, 0.206 parts of stearyl phosphate (Phoslex A-18, manufactured by Sakai Chemical Industry Co., Ltd.) were added to the obtained polymerization solution as a catalyst for the cyclization condensation reaction (cyclization catalyst), and the cyclization condensation reaction to form a lactone ring structure was carried out under reflux at approximately 90-110°C for 2 hours. Then, the obtained polymerization solution was passed through a multi-tube heat exchanger heated to 240°C to complete the cyclization condensation reaction, and defoliation was carried out using a vent-type screw twin-screw extruder (L / D=52) with a barrel temperature of 250°C, one rear vent, four fore vents (referred to as the 1st, 2nd, 3rd, and 4th vents from the upstream side), and a side feeder between the 3rd and 4th vents, with a leaf-disc type polymer filter (filtration accuracy 5 μm) positioned at the tip.

[0152] After the devolatilization was completed, the resin composition in the hot molten state remaining in the extruder was discharged while being filtered through the polymer filter from the tip of the extruder, passed through the provided die, then filtered through a filter with a pore diameter of 1 μm (product name: Micro Pore Filter 1EU, manufactured by Organo Corporation), and cooled in a water tank filled with cooling water maintained at a temperature within the range of 30 ± 10°C. Subsequently, by introducing it into a cutter (pelletizer), pellets of the resin composition containing the (meth)acrylic polymer 1 were obtained. The Mw of the obtained (meth)acrylic polymer 1 was 132,000, the Mn was 59,000, and the glass transition temperature was 121°C.

[0153] Production Example 2 A reactor equipped with a stirring device, a temperature sensor, a cooling pipe, and a nitrogen introduction pipe was prepared. 75 parts of deionized water in which 1 part of Hytenol (registered trademark) NF-08 was dissolved was charged into a container. Next, a mixed solution in which 13 parts of α-methylene-γ-butyrolactone (ML) as a monomer, 37 parts of methyl methacrylate (MMA), and 0.25 parts of Peroyl L (dilauroyl peroxide, LPO) as a polymerization initiator were mixed in advance was charged into the container, and it was stirred at 3000 rpm for 15 minutes using a T.K. Homomixer MARK II model 2.5 (manufactured by Primix) to obtain a uniform suspension.

[0154] 125 parts of deionized water was added to the suspension and then transferred to the reactor, and while stirring, nitrogen gas was blown in and heated until the reaction solution (suspension) reached 65°C. The time when the internal temperature reached 65°C was taken as the start of the reaction, and the reactor was kept at 65°C as it was. After the liquid temperature reached the peak temperature due to self-heating, it was kept at 75°C. Further, 2 hours after the start of the reaction, the reaction solution (suspension) was heated to 90°C and stirred for 4 hours to complete the polymerization reaction. Thereafter, the reaction solution was cooled, filtered, and the copolymer was collected by filtration, and further dried using a hot air dryer to obtain the (meth)acrylic polymer 2 (powder). The Mw of the obtained (meth)acrylic polymer 2 was 252,000, the Mn was 119,000, and the glass transition temperature was 127°C.

[0155] Production Example 3 Into a reactor equipped with a stirring device, a temperature sensor, a cooling pipe, and a nitrogen introduction pipe, 67.5 parts of methyl methacrylate (MMA), 15.7 parts of phenyl maleimide (PMI), 0.03 part of n-dodecyl mercaptan (nDM), and 100 parts of toluene as a polymerization solvent were charged, and while passing nitrogen through it, the temperature was raised to 105°C. Then, 0.04 part of t-butyl peroxyisopropyl carbonate (manufactured by Kayaku Akzo Co., Ltd., Kayacarbon (registered trademark) Bic75) was added as a polymerization initiator, and 1.8 parts of styrene (St) and 0.15 part of t-butyl peroxyisopropyl carbonate diluted in 1 part of toluene were added dropwise at a constant rate over 3 hours while performing solution polymerization at 105 - 110°C, and further aging was carried out for 4 hours.

[0156] Next, the obtained polymerization reaction solution was devolatilized using a vent-type screw twin-screw extruder with 1 rear vent and 2 front vents, and then introduced into a cutter (pelletizer) to obtain pellets of a transparent resin composition containing (meth)acrylic polymer 3. The Mw of the obtained (meth)acrylic polymer 3 was 148,000, the Mn was 56,000, and the glass transition temperature was 137°C.

[0157] Example 1 The pellets of the resin composition containing (meth)acrylic polymer 1 obtained in Production Example 1 were dried at 80°C for 8 hours, then dissolved in methylene chloride to a solid content concentration of 20%, and a compound (ultraviolet absorber A) represented by the following formula (1-1) was added in an amount of 2.4 parts per 100 parts of the (meth)acrylic polymer. After mixing, it was allowed to stand for 24 hours to remove the bubbles in the solution, and Dope 1 was obtained.

[0158]

Chemical formula

[0159] In a clean booth filled with dry air, dope 1 was cast onto a support (PET film: surface roughness Ra of 0.02-0.04 μm) using a bar coater to a dry film thickness of 100 μm. The solvent was evaporated by heating at 40-60°C, and the resulting film (doped film) was peeled off the support. An unstretched film was obtained by drying the film at 80-120°C while applying a tension of 3 kg per 100 cm width. The obtained unstretched film was cut to a size of 96 mm x 96 mm, and a stretched film was obtained by sequential biaxial stretching using a sequential biaxial stretcher (Toyo Seiki Seisakusho Co., Ltd., X6-S) at a temperature of Tg + 18°C ​​at a stretching rate of 300% / min, sequentially stretching in the longitudinal direction (MD direction) and transverse direction (TD direction) to a facet ratio of 5.0, and then cooling. The properties of the obtained film are shown in Table 1.

[0160] Examples 2-5, Comparative Examples 1, 2 Except for changing the type of (meth)acrylic polymer used and the type and / or amount of UV absorber used as shown in Table 1, the dope was prepared in the same manner as in Example 1, and a film was formed using the obtained dope in the same manner as in Example 1. The physical properties of each film are shown in Table 1.

[0161] [Table 1]

[0162] In Table 1, the components are as follows: (meth)acrylic polymer 1; (meth)acrylic polymer 1 having a lactone ring structure in the main chain obtained in the above production example 1 (meth)acrylic polymer 2; (meth)acrylic polymer 2 having a lactone ring structure in the main chain obtained in the above production example 2. (Meth)acrylic polymer 3; (Meth)acrylic polymer 3 having an N-substituted maleimide structure in the main chain obtained in the above production example 3 (Meth)acrylic polymer 4; glutarimide structure located in the main chain (R in formula (2X) above) 4a and R 5a(Meth)acrylic polymer having units containing a methyl group and methyl methacrylate units as constituent units (Daicel-Evonik, Pleximide 8813, Glutalimide unit content 42% by weight, Tg: 132℃, Mw: 115,000, Mn: 55,000) UV absorber A; compound represented by the above formula (1-1) UV absorber B; ADEKA stub LAF70 (manufactured by ADEKA)

[0163] Comparative Example 3 In Production Example 1, (meth)acrylic polymer 1 was mixed with 2.4 parts of ultraviolet absorber A (a compound represented by formula (1-1) above) per 100 parts of (meth)acrylic polymer 1 using a twin-screw kneader, and then introduced into a pelletizer to obtain pellets of a resin composition containing (meth)acrylic polymer 1 and ultraviolet absorber A. The obtained pellets were loaded into a vented single-screw extruder with a diameter of Φ65 mm, an L / D ratio of 32, and a Unimelt screw. The temperatures of the extruder's cylinder, gear pump, polymer filter, and T-die were set to 265°C. The pellets were heated to 60°C by blowing heated, dehumidified air into the hopper. In addition, a nitrogen inlet pipe was installed at the bottom of the hopper to introduce nitrogen gas into the extruder.

[0164] While suction is applied from the vent at 40 Torr, the pellets are melted with a single-screw motor, and a gear pump is used to filter the pellets over a filtration area of ​​0.75 m². 2 The molten resin was then passed through a polymer filter with a leaf disc filter having a filtration accuracy of 10 μm. Next, the molten resin was extruded from a 600 mm wide T-die, and a film was formed on a cooling roll at 120°C. The thickness of the resulting film was 100 μm. In addition, some of the UV absorber used bled out onto the surface of the resulting film, resulting in a defect in appearance.

Claims

1. A dope comprising a (meth)acrylic polymer having a ring structure in its main chain and an ultraviolet absorber represented by the following formula (5), The amount of the ultraviolet absorber is 0.5 parts by mass or more and 6 parts by mass or less per 100 parts by mass of the (meth)acrylic polymer. Dope for manufacturing optical films by solution deposition method. 【Chemistry 1】 [In formula (5), R 1x and R 1y Each of these independently represents a cyano group, an acyl group, a carboxyl group, a carboxylic acid ester group, or an amide group. R 2x and R 2y Each of these independently represents a hydrogen atom, a cyano group, an acyl group, a carboxyl group, a carboxylic acid ester group, an amide group, a hydrocarbon group, or a heteroaryl group. R 1x and R 2x If both are acyl groups, carboxylic acid ester groups, or amide groups, R 1x and R 2x They may be connected to each other to form a ring. R 1y and R 2y are both an acyl group, a carboxylic acid ester group, or an amide group, R 1y and R 2y may be linked to each other to form a ring, R 3x and R 3y Each of these independently represents a hydrogen atom or an alkyl group. L represents one of the divalent linking groups shown in formulas (4-1) to (4-9) below. 【Chemistry 2】 [In formulas (4-1) to (4-9), * indicates the binding site with group S in formula (5).

2. The dope according to claim 1, wherein the ring structure of the main chain of the (meth)acrylic polymer is at least one selected from the group consisting of a lactone ring structure, a glutarimide structure, a glutaric acid anhydride structure, a maleic acid anhydride structure, and an N-substituted maleimide structure.

3. A method for producing a film, comprising the steps of preparing a dope according to claim 1 or 2, and then casting or coating the prepared dope onto a support and drying it.

4. A film comprising a (meth)acrylic polymer having a ring structure in its main chain and an ultraviolet absorber, The light transmittance at a wavelength of 400 nm is 15% or less. The in-plane phase difference Re for light with a wavelength of 589 nm is 10 nm or less, and the absolute value of the thickness-direction phase difference Rth for light with a wavelength of 589 nm is 20 nm or less. A film containing a compound represented by the following formula (5) as the ultraviolet absorber. 【Transformation 3】 [In formula (5), R 1x and R 1y Each of these independently represents a cyano group, an acyl group, a carboxyl group, a carboxylic acid ester group, or an amide group. R 2x and R 2y Each of these independently represents a hydrogen atom, a cyano group, an acyl group, a carboxyl group, a carboxylic acid ester group, an amide group, a hydrocarbon group, or a heteroaryl group. R 1x and R 2x If both are acyl groups, carboxylic acid ester groups, or amide groups, R 1x and R 2x They may be connected to each other to form a ring. R 1y and R 2y If both are acyl groups, carboxylic acid ester groups, or amide groups, R 1y and R 2y They may be connected to each other to form a ring. R 3x and R 3y Each of these independently represents a hydrogen atom or an alkyl group. L represents a divalent linking group.

5. The film according to claim 4, wherein the internal haze is 1.0% or less.

6. The film according to claim 4 or 5, wherein the ring structure of the main chain of the (meth)acrylic polymer is at least one selected from the group consisting of a lactone ring structure, a glutarimide structure, a glutaric acid anhydride structure, a maleic acid anhydride structure, and an N-substituted maleimide structure.

7. An organic electroluminescent display device comprising the film described in any one of claims 4 to 6.

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