Resin film for optical film and method for producing resin film for optical film

Abstract

To provide a resin film for optical film, the birefringence of which is adjusted in the negative direction, and a method for producing the same. The present invention provides a resin film for optical films, which contains an amorphous resin having positive birefringence and a diacetal compound represented by formula (1). In the film, the diacetal compound exists in a crystalline or aggregated state that exhibits negative birefringence. TIFF0007813932000015.tif60138

Description

[Technical Field]

[0001] The present invention relates to a resin film for an optical film and a method for producing a resin film for an optical film. [Background technology]

[0002] Acrylic acid-based resin films with distinctive optical properties are known. For example, Patent Document 1 discloses a resin film for optical film, which is composed of a methacrylic acid ester-based polymer and a diacetal compound having a specific structure. The resin film disclosed in Patent Document 1 is disclosed to be characterized by the absence of poor dispersion and low birefringence. It is also disclosed that the resin film produced in Patent Document 1 contains a diacetal compound, which causes the orientation birefringence to shift to the positive direction, resulting in a lower birefringence than a resin film that does not contain a diacetal compound.

[0003] Patent Document 2 discloses a substrate for a surface protection film for protecting the surface of an image display device. The substrate for a surface protection film disclosed in Patent Document 2 is characterized by having a retardation property within a specific range. It is disclosed that the specific composition of this film substrate includes at least one resin selected from polycarbonate, polyester, cycloolefin resin, acrylic resin, and cellulose resin. It is also disclosed that the film substrate may include a resin having an alicyclic structure or an aromatic ring structure that exhibits negative intrinsic birefringence. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-254730 [Patent Document 2] WO2020 / 054135 publication Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to provide a resin film for optical films, which contains a resin having positive birefringence and a diacetal compound and in which the birefringence is adjusted in the negative direction, and a method for producing the same. [Means for solving the problem]

[0006] The resin film for optical film according to the present disclosure is a film containing an amorphous resin having positive birefringence and a diacetal compound represented by formula (1). In the film, the diacetal compound exists as a crystal or an aggregated state exhibiting negative birefringence. [ka] (In the formula, R 1 , R 2 , R 3 , R 4 , R 5 and R 6 are the same or different and each represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, an alkoxycarbonyl group having 1 to 4 carbon atoms, a halogenated alkyl group having 1 to 4 carbon atoms, or a halogen atom. 7 represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkenyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, an alkoxycarbonyl group having 1 to 4 carbon atoms, or a halogenated alkyl group having 1 to 4 carbon atoms. [Effects of the Invention]

[0007] The resin film according to the present disclosure contains a resin having positive birefringence and a diacetal compound, and the birefringence is adjusted to the negative direction. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a TEM image of the resin film of Example 4. DETAILED DESCRIPTION OF THE INVENTION

[0009] [Outline of the embodiment] First, embodiments of the resin film for optical film and the manufacturing method thereof according to the present disclosure will be listed and described. In this specification, unless otherwise specified, "A to B" representing a numerical range means "A or more and B or less."

[0010] The resin film for optical film according to the present disclosure is a film containing an amorphous resin having positive birefringence and a diacetal compound represented by formula (1). In the film, the diacetal compound exists as a crystal or an aggregated state exhibiting negative birefringence. [ka] (In the formula, R 1 , R 2 , R 3 , R 4 , R 5 and R 6 are the same or different and each represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, an alkoxycarbonyl group having 1 to 4 carbon atoms, a halogenated alkyl group having 1 to 4 carbon atoms, or a halogen atom. 7 represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkenyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, an alkoxycarbonyl group having 1 to 4 carbon atoms, or a halogenated alkyl group having 1 to 4 carbon atoms.

[0011] Many proposals have been made for resin films with adjusted optical properties. As mentioned above, Patent Document 2 proposes a film in which a chemical structure exhibiting negative birefringence is incorporated into the side chain of the resin constituting the film. Meanwhile, Patent Document 1 describes kneading a methacrylate ester polymer and a diacetal compound, dissolving the diacetal compound in the molten methacrylate ester polymer, and obtaining a mixture in which the diacetal compound is uniformly dispersed in the polymer.

[0012] In Examples 1 and 2 of Patent Document 1, it is described that a film was obtained in which the diacetal compound was not dissolved in polymethyl methacrylate but was dispersed in a powdery state. In Example 3, it is described that a film produced by a method different from those of Examples 1 and 2 had the same orientation birefringence and photoelastic coefficient as Example 1. However, in both cases, the specific dispersion state of the diacetal compound is unknown. Furthermore, the presence of the diacetal compound shifts the birefringence in the positive direction.

[0013] In contrast, in the resin film for optical films according to the present disclosure, the birefringence is adjusted to the negative direction by the diacetal compound, and the film according to the present disclosure has an excellent birefringence control effect, and a resin film for optical films having birefringence adjusted to the negative direction or a resin film for optical films having no birefringence can be obtained.

[0014] In the resin film for optical films, the diacetal compound may be contained in an amount of 1% to 20% based on the amorphous resin, which allows the diacetal compound to be reliably precipitated in the film, thereby obtaining a film with birefringence adjusted in the negative direction.

[0015] In the resin film for an optical film, the amorphous resin may be a resin containing at least one selected from the group consisting of a cycloolefin resin, a polycarbonate resin, and a polyester resin.

[0016] The method for producing a resin film for an optical film according to the present disclosure includes the steps of: heat-mixing an amorphous resin having positive birefringence with a diacetal compound represented by formula (1) at a temperature equal to or higher than the softening point of the amorphous resin, thereby dissolving the diacetal compound in the amorphous resin, thereby obtaining a resin composition; a step of molding the resin composition while applying a shear force to the resin composition at a temperature equal to or higher than the glass transition point of the amorphous resin; a step of cooling the mixture while applying a shear force continuously from the molding step; Includes. [ka] (In the formula, R 1 , R 2 , R 3 , R 4 , R 5 and R 6 are the same or different and each represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, an alkoxycarbonyl group having 1 to 4 carbon atoms, a halogenated alkyl group having 1 to 4 carbon atoms, or a halogen atom. 7 represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkenyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, an alkoxycarbonyl group having 1 to 4 carbon atoms, or a halogenated alkyl group having 1 to 4 carbon atoms.

[0017] In the above-described manufacturing method, the diacetal compound exists in the resin film for an optical film in a crystalline or aggregated state, and the diacetal compound adjusts birefringence in the negative direction. According to this manufacturing method, a resin film having birefringence properties controlled in the negative direction can be obtained.

[0018] The resin film according to the present disclosure will be described in more detail below.

[0019] (resin) The resin film according to the present disclosure contains an amorphous resin having positive birefringence as the base resin constituting the film. The amorphous resin is not particularly limited as long as it has positive birefringence and transparency appropriate for the intended use. Examples of amorphous resins having positive birefringence include polycarbonate resins, polyester resins, cycloolefin resins, polyimide resins, and cellulose ester resins. Among these, from the viewpoints of productivity and cost, it is preferable that the resin having positive birefringence includes at least one selected from the group consisting of cycloolefin resins, polycarbonate resins, and polyester resins.

[0020] The resin film according to the present disclosure has as its base an amorphous resin having positive birefringence, but the birefringence is adjusted in the negative direction, and the birefringence of the resin film may be positive, negative, or may not exhibit birefringence (0). In the resin film according to the present disclosure, the diacetal compound exists in the film in a crystalline or associated state, and the diacetal compound adjusts the birefringence in the negative direction.

[0021] The birefringence of a resin film is determined by the refractive index (n x , n y ) and is expressed by the following formula: Δn=n x -n y In the above formula, n x is the refractive index of the slow axis, n y represents the refractive index of the fast axis. When the resin film has positive birefringence, n x >n y The refractive index of the slow axis in the flow or deformation direction is higher than the refractive index of the fast axis in the direction perpendicular to the flow or deformation direction. When a resin film has negative birefringence, n x <n y and the refractive index of the fast axis is higher than the refractive index of the slow axis. The birefringence of the resin film can be measured using a polarizing microscope in accordance with a known method, and a specific method for measuring the birefringence will be described in detail in the Examples. In this specification, the term "birefringence adjusted in the negative direction" means that the birefringence value (Δn) of a resin film containing an acetal compound specified by formula (1) is adjusted to a value (Δn) of birefringence of a resin film not containing an acetal compound specified by formula (1). ad ) is small.

[0022] When the resin used as the base of the resin film is a polycarbonate resin, the polycarbonate resin may be any known resin used as an optical resin without any particular limitation. Examples of the polycarbonate resin include bisphenol-based polycarbonate resins and isosorbide-based polycarbonate resins. The bisphenol-based polycarbonate resin may be, for example, an aromatic polycarbonate resin containing a structural unit (carbonate structural unit) composed of bisphenol A or bisphenol C.

[0023] Bisphenol A polycarbonate resins are resins having carbonate structural units derived from bisphenol A and its derivatives. The content of structural units derived from bisphenol A in bisphenol A polycarbonate resins is preferably 70 mol% or more, more preferably 80 mol% or more, and even more preferably 90 mol% or more, of all structural units excluding both terminals. There are no particular upper limits, and 100 mol% may be structural units derived from bisphenol A. Preferred examples of bisphenol A polycarbonates include resins in which substantially all structural units excluding both terminals are composed of structural units derived from bisphenol A. Bisphenol A polycarbonate resins may have structural units other than carbonate structural units derived from bisphenol A and its derivatives, and the other structural units may be structural units derived from aromatic dihydroxy compounds.

[0024] Examples of isosorbide-based polycarbonate resins include those containing structural units derived from isosorbide and structural units derived from aliphatic dihydroxy compounds and / or alicyclic dihydroxy compounds. Examples of aliphatic dihydroxy compounds include 1,4-butanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 2-ethyl-1,6-hexanediol, 2,2,4-trimethyl-1,6-hexanediol, 1,9-nonanediol, 1,10-decanediol, hydrogenated dilinoleyl glycol, and hydrogenated dioleyl glycol. Examples of the alicyclic dihydroxy compound include compounds having a 5-membered ring structure or a 6-membered ring structure, such as cyclohexanedimethanol, tricyclodecanedimethanol, pentacyclopentadecanedimethanol, decalindimethanol, tricyclotetradecanedimethanol, norbornanedimethanol, and adamantanedimethanol, as well as tricyclodecanediol, pentacyclopentadecanediol, decalindiol, tricyclotetradecanediol, norbornanediol, and adamantanediol.

[0025] The polycarbonate resin may be any commercially available optical resin, such as the "Iupilon" series manufactured by Mitsubishi Gas Chemical Company, Inc., the "Panlite" series manufactured by Teijin Limited, or the "Durabio" series manufactured by Mitsubishi Chemical Corporation.

[0026] When the resin serving as the substrate of the resin film is a polyester resin, the polyester resin is used as an optical resin, and any known resin having positive birefringence can be used without particular limitation. The polyester resin is obtained by polymerizing a dicarboxylic acid and a diol, and it is preferable that 70% or more of the dicarboxylic acid structural units (structural units derived from dicarboxylic acid) are derived from an aromatic dicarboxylic acid, and 70% or more of the diol structural units (structural units derived from diol) are derived from an aliphatic diol.

[0027] Examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, naphthalenedicarboxylic acids such as 2,6-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, and 2,7-naphthalenedicarboxylic acid, 4,4'-biphenyldicarboxylic acid, and 3,4'-biphenyldicarboxylic acid, and ester-forming derivatives thereof.

[0028] Examples of the aliphatic diol include ethylene glycol, 1,3-propylene diol, 1,4-butanediol, 1,4-cyclohexanedimethanol, 1,6-hexanediol, and ester-forming derivatives thereof.

[0029] Preferred examples of polyester resins include polyethylene terephthalate resin, polyethylene terephthalate-isophthalate copolymer resin, polyethylene-1,4-cyclohexanedimethylene-terephthalate copolymer resin, polyethylene-2,6-naphthalenedicarboxylate resin, polyethylene-2,6-naphthalenedicarboxylate-terephthalate copolymer resin, polyethylene-terephthalate-4,4'-biphenyldicarboxylate resin, poly-1,3-propylene-terephthalate resin, polybutylene terephthalate resin, and polybutylene-2,6-naphthalenedicarboxylate resin.

[0030] As the polyester resin, commercially available optical resins can be used, such as the "Byron" series from Toyobo Co., Ltd., the "Tritan" series from Eastman Chemical Co., Ltd., and the "Ecozen" series from SK Chemical Co., Ltd.

[0031] When the resin used as the base of the resin film is a cycloolefin resin, any known resin used as an optical resin can be used without any particular limitation. The cycloolefin resin may be a resin made of a cycloolefin polymer obtained by polymerizing a copolymerizable cyclic olefin monomer, a resin made of a cycloolefin copolymer obtained by polymerizing a cyclic olefin compound with another monomer, or a resin made of a mixture thereof. Examples of copolymerizable monomers include cyclobutene, cyclopentene, cycloheptene, cyclooctene, and dicyclopentadiene. The cycloolefin resin may contain polymers of one or more of these monomers.

[0032] As the cycloolefin resin, commercially available optical resins can be used, such as the "Zeonex" series from Nippon Zeon Co., Ltd., the "Arton" series from JSR Corporation, and the "Apel" series from Mitsui Chemicals, Inc.

[0033] When the resin used as the base of the resin film is a polyimide resin, the polyimide resin may be any known resin used as an optical resin without any particular limitation. As the polyimide resin, commercially available optical resins may be used, such as the "Surprim" series manufactured by Mitsubishi Gas Chemical Company, Inc. and the "Aurum" series manufactured by Mitsui Chemicals Co., Ltd.

[0034] When the resin used as the base of the resin film is a cellulose ester resin, the cellulose ester resin may be any known resin used as an optical resin, without any particular limitation. Examples of the cellulose ester resin include cellulose acetate propionate resin and cellulose acetate butyrate resin. The cellulose ester resin may be a commercially available optical resin, such as Nagase & Co., Ltd.'s "CAB" series or "CAP" series.

[0035] (Optical adjuster) The resin film for optical film according to the present disclosure is characterized by containing a diacetal compound represented by formula (1). This diacetal compound functions as an optical adjuster that adjusts the optical properties of the film. According to the present disclosure, by containing a diacetal compound with a specific structure, crystals or associations exhibiting negative birefringence exist in a fibrous form, and a resin film with birefringence adjusted in the negative direction can be obtained.

[0036] [ka] (In the formula, R 1 , R 2 , R 3 , R 4 , R 5 and R 6 are the same or different and each represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, an alkoxycarbonyl group having 1 to 4 carbon atoms, a halogenated alkyl group having 1 to 4 carbon atoms, or a halogen atom. 7 represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkenyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, an alkoxycarbonyl group having 1 to 4 carbon atoms, or a halogenated alkyl group having 1 to 4 carbon atoms.

[0037] From the viewpoint of obtaining the function of adjusting the birefringence of resin films by precipitating them in resin films for optical films, R 1 , R 2 , R 3 , R 4 , R 5 and R 6 may be the same or different, and are preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. 1 , R 2 and R 3 One of R may be a hydrogen atom and two may be alkyl groups having 1 to 4 carbon atoms. 1 , R 2 and R 3 Two of the R groups may be hydrogen atoms and one may be an alkyl group having 1 to 4 carbon atoms. 4 , R 5 and R6 One of R may be a hydrogen atom and two may be alkyl groups having 1 to 4 carbon atoms. 4 , R 5 and R 6 Two of the R groups may be hydrogen atoms and one may be an alkyl group having 1 to 4 carbon atoms. 1 , R 2 , R 3 , R 4 , R 5 and R 6 may all be hydrogen atoms.

[0038] R 7 is preferably a hydrogen atom, an alkyl group having 1 to 4 carbon atoms or an alkenyl group having 1 to 4 carbon atoms, and more preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.

[0039] As shown in equation (1), R 7 Specific examples of compounds in which is a hydrogen atom include: 1,3:2,4-bis-O-benzylidene-D-sorbitol, 1,3:2,4-bis-O-(o-methylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(m-methylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(p-methylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(o-ethylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(m-ethylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(p-ethylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(o-isopropylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(m-isopropylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(p-isopropylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(on-propylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(mn-propylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(pn-propylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(on-butylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(mn-butylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(pn-butylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(o-tert-butylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(m-tert-butylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(p-tert-butylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(2',3'-dimethylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(2',4'-dimethylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(2',5'-dimethylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(3',4'-dimethylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(3',5'-dimethylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(2',3'-diethylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(2',4'-diethylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(2',5'-diethylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(3',4'-diethylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(3',5'-diethylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(2',4',5'-trimethylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(3',4',5'-trimethylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(2',4',5'-triethylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(3',4',5'-triethylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(o-methoxybenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(m-methoxybenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(p-methoxybenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(o-ethoxybenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(m-ethoxybenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(p-ethoxybenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(o-isopropoxybenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(m-isopropoxybenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(p-isopropoxybenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(on-propoxybenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(mn-propoxybenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(pn-propoxybenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(o-methoxycarbonylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(m-methoxycarbonylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(p-methoxycarbonylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(o-ethoxycarbonylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(m-ethoxycarbonylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(p-ethoxycarbonylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(o-isopropoxycarbonylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(m-isopropoxycarbonylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(p-isopropoxycarbonylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(on-propoxycarbonylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(mn-propoxycarbonylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(pn-propoxycarbonylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(o-fluorobenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(m-fluorobenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(p-fluorobenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(o-chlorobenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(m-chlorobenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(p-chlorobenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(o-bromobenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(m-bromobenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(p-bromobenzylidene)-D-sorbitol, 1,3-O-benzylidene-2,4-O-(p-methylbenzylidene)-D-sorbitol, 1,3-O-(p-methylbenzylidene)-2,4-O-benzylidene-D-sorbitol, 1,3-O-benzylidene-2,4-O-(p-ethylbenzylidene)-D-sorbitol, 1,3-O-(p-ethylbenzylidene)-2,4-O-benzylidene-D-sorbitol, 1,3-O-benzylidene-2,4-O-(p-chlorobenzylidene)-D-sorbitol, 1,3-O-(p-chlorobenzylidene)-2,4-O-benzylidene-D-sorbitol, 1,3-O-benzylidene-2,4-O-(2',4'-dimethylbenzylidene)-D-sorbitol, 1,3-O-(2',4'-dimethylbenzylidene)-2,4-O-benzylidene-D-sorbitol, 1,3-O-benzylidene-2,4-O-(3',4'-dimethylbenzylidene)-D-sorbitol, 1,3-O-(3',4'-dimethylbenzylidene)-2,4-O-benzylidene-D-sorbitol, 1,3-O-(p-methylbenzylidene)-2,4-O-(p-ethylbenzylidene)-D-sorbitol, 1,3-O-(p-ethylbenzylidene)-2,4-O-(p-methylbenzylidene)-D-sorbitol, 1,3-(p-methylbenzylidene)-2,4-O-(3',4'-dimethylbenzylidene)-D-sorbitol, 1,3-O-(3',4'-dimethylbenzylidene)-2,4-O-(p-methylbenzylidene)-D-sorbitol, 1,3-(p-ethylbenzylidene)-2,4-O-(3',4'-dimethylbenzylidene)-D-sorbitol, 1,3-O-(3',4'-dimethylbenzylidene)-2,4-O-(p-ethylbenzylidene)-D-sorbitol, 1,3-O-(p-methylbenzylidene)-2,4-O-(p-chlorobenzylidene)-D-sorbitol, Examples include 1,3-O-(p-chlorobenzylidene)-2,4-O-(p-methylbenzylidene)-D-sorbitol.

[0040] As shown in equation (1), R 7 Specific examples of compounds in which is a methyl group include: 1,3:2,4-bis-O-benzylidene-1-methylsorbitol, 1,3:2,4-bis-O-(p-methylbenzylidene)-1-methylsorbitol, 1,3:2,4-bis-O-(p-ethylbenzylidene)-1-methylsorbitol, 1,3:2,4-bis-O-(pn-propylbenzylidene)-1-methylsorbitol, 1,3:2,4-bis-O-(2',3'-dimethylbenzylidene)-1-methylsorbitol, 1,3:2,4-bis-O-(2',4'-dimethylbenzylidene)-1-methylsorbitol, 1,3:2,4-bis-O-(2',5'-dimethylbenzylidene)-1-methylsorbitol, 1,3:2,4-bis-O-(3',4'-dimethylbenzylidene)-1-methylsorbitol, 1,3:2,4-bis-O-(3',5'-dimethylbenzylidene)-1-methylsorbitol, 1,3:2,4-bis-O-(3'-methyl-4'-methoxybenzylidene)-1-methylsorbitol, 1,3:2,4-bis-O-(3',4'-dichlorobenzylidene)-1-methylsorbitol, 1,3:2,4-bis-O-(p-methoxycarbonylbenzylidene)-1-methylsorbitol, 1,3:2,4-bis-O-(3'-methyl-4'-fluorobenzylidene)-1-methylsorbitol, Examples include 1,3:2,4-bis-O-(3'-bromo-4'-ethylbenzylidene)-1-methylsorbitol.

[0041] As shown in equation (1), R 7 Specific examples of compounds in which is an ethyl group include: 1,3:2,4-bis-O-benzylidene-1-ethyl sorbitol, 1,3:2,4-bis-O-(p-methylbenzylidene)-1-ethylsorbitol, 1,3:2,4-bis-O-(p-ethylbenzylidene)-1-ethylsorbitol, 1,3:2,4-bis-O-(pn-propylbenzylidene)-1-ethylsorbitol, 1,3:2,4-bis-O-(2',3'-dimethylbenzylidene)-1-ethylsorbitol, 1,3:2,4-bis-O-(2',4'-dimethylbenzylidene)-1-ethylsorbitol, 1,3:2,4-bis-O-(2',5'-dimethylbenzylidene)-1-ethylsorbitol, 1,3:2,4-bis-O-(3',4'-dimethylbenzylidene)-1-ethylsorbitol, 1,3:2,4-bis-O-(3',5'-dimethylbenzylidene)-1-ethylsorbitol, 1,3:2,4-bis-O-(3'-methyl-4'-methoxybenzylidene)-1-ethylsorbitol, 1,3:2,4-bis-O-(3',4'-dichlorobenzylidene)-1-ethylsorbitol, 1,3:2,4-bis-O-(p-methoxycarbonylbenzylidene)-1-ethylsorbitol, 1,3:2,4-bis-O-(3'-methyl-4'-fluorobenzylidene)-1-ethylsorbitol, Examples include 1,3:2,4-bis-O-(3'-bromo-4'-ethylbenzylidene)-1-ethylsorbitol.

[0042] As shown in equation (1), R 7 Specific examples of compounds in which is an n-propyl group include: 1,3:2,4-bis-O-benzylidene-1-n-propyl sorbitol, 1,3:2,4-bis-O-(p-methylbenzylidene)-1-n-propyl sorbitol, 1,3:2,4-bis-O-(p-ethylbenzylidene)-1-n-propyl sorbitol, 1,3:2,4-bis-O-(pn-propylbenzylidene)-1-n-propyl sorbitol, 1,3:2,4-bis-O-(2',3'-dimethylbenzylidene)-1-n-propyl sorbitol, 1,3:2,4-bis-O-(2',4'-dimethylbenzylidene)-1-n-propyl sorbitol, 1,3:2,4-bis-O-(2',5'-dimethylbenzylidene)-1-n-propyl sorbitol, 1,3:2,4-bis-O-(3',4'-dimethylbenzylidene)-1-n-propyl sorbitol, 1,3:2,4-bis-O-(3',5'-dimethylbenzylidene)-1-n-propyl sorbitol, 1,3:2,4-bis-O-(3'-methyl-4'-methoxybenzylidene)-1-n-propyl sorbitol, 1,3:2,4-bis-O-(3',4'-dichlorobenzylidene)-1-n-propyl sorbitol, 1,3:2,4-bis-O-(p-methoxycarbonylbenzylidene)-1-n-propyl sorbitol, 1,3:2,4-bis-O-(3'-methyl-4'-fluorobenzylidene)-1-n-propyl sorbitol, Examples include 1,3:2,4-bis-O-(3'-bromo-4'-ethylbenzylidene)-1-n-propyl sorbitol.

[0043] As shown in equation (1), R 7 Specific examples of compounds in which is an allyl group include: 1,3:2,4-bis-O-benzylidene-1-allyl sorbitol, 1,3:2,4-bis-O-(p-methylbenzylidene)-1-allyl sorbitol, 1,3:2,4-bis-O-(p-ethylbenzylidene)-1-allyl sorbitol, 1,3:2,4-bis-O-(pn-propylbenzylidene)-1-allyl sorbitol, 1,3:2,4-bis-O-(2',3'-dimethylbenzylidene)-1-allyl sorbitol, 1,3:2,4-bis-O-(2',4'-dimethylbenzylidene)-1-allyl sorbitol, 1,3:2,4-bis-O-(2',5'-dimethylbenzylidene)-1-allyl sorbitol, 1,3:2,4-bis-O-(3',4'-dimethylbenzylidene)-1-allyl sorbitol, 1,3:2,4-bis-O-(3',5'-dimethylbenzylidene)-1-allyl sorbitol, 1,3:2,4-bis-O-(3'-methyl-4'-methoxybenzylidene)-1-allyl sorbitol, 1,3:2,4-bis-O-(3',4'-dichlorobenzylidene)-1-allyl sorbitol, 1,3:2,4-bis-O-(p-methoxycarbonylbenzylidene)-1-allyl sorbitol, 1,3:2,4-bis-O-(3'-methyl-4'-fluorobenzylidene)-1-allyl sorbitol, Examples thereof include 1,3:2,4-bis-O-(3'-bromo-4'-ethylbenzylidene)-1-allyl sorbitol.

[0044] As shown in equation (1), R 7 Further examples of compounds in which is a hydrogen atom include: bis-1,3:2,4-(4'-ethyl-2'-methylbenzylidene) sorbitol, bis-1,3:2,4-(4'-normal propyl-2'-methylbenzylidene) sorbitol, bis-1,3:2,4-(4'-isopropyl-2'-methylbenzylidene) sorbitol, bis-1,3:2,4-(4'-n-butyl-2'-methylbenzylidene) sorbitol, bis-1,3:2,4-(4'-isobutyl-2'-methylbenzylidene) sorbitol, bis-1,3:2,4-(4'-tert-butyl-2'-methylbenzylidene) sorbitol, bis-1,3:2,4-(4'-secbutyl-2'-methylbenzylidene) sorbitol, bis-1,3:2,4-(4'-normal pentyl-2'-methylbenzylidene) sorbitol, bis-1,3:2,4-(4'-isopentyl-2'-methylbenzylidene) sorbitol, bis-1,3:2,4-(4'-neopentyl-2'-methylbenzylidene) sorbitol, bis-1,3:2,4-(4'-tert-pentyl-2'-methylbenzylidene) sorbitol, Examples thereof include bis-1,3:2,4-(4'-secpentyl-2'-methylbenzylidene) sorbitol.

[0045] R 7 may be any of a methyl group, an ethyl group, a propyl group, and a butyl group. For example, R 7 When R is a methyl group, the compound represented by formula (1) can be exemplified by 1-methylsorbitol having the benzylidene structure listed above. 7 is an ethyl group), 1-n-propyl sorbitol (R 7 is an n-propyl group), 1-allyl sorbitol (R 7 is a 2-propenyl group). The resin film according to the present disclosure can contain one or more of these compounds.

[0046] More preferred examples of the compound represented by formula (1) include 1,3:2,4-bis-O-benzylidene-D-sorbitol, 1,3:2,4-bis-O-(p-methylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(p-ethylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(3',4'-dimethylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(pn-propylbenzylidene)-1-methylsorbitol, 1,3:2,4-bis-O-(pn-propylbenzylidene)-1-ethylsorbitol, and 1,3:2,4-bis-O-(pn-propylbenzyl)-1-methylsorbitol.

[0033] More preferred are 1,3:2,4-bis-O-(p-methylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(p-ethylbenzylidene)-D-sorbitol and 1,3:2,4-bis-O-(p-propylbenzylidene)-1-n-propyl sorbitol.

[0034] More preferred are 1,3:2,4-bis-O-(p-methylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(p-ethylbenzylidene)-D-sorbitol and 1,3:2,4-bis-O-(p-propylbenzylidene)-1-n-propyl sorbitol.

[0047] Diacetal compounds are commercially available, for example, under the trade names Gelall D, Gelall MD, Gelall DXR, Lika-ijust-100, Lika-ijust-200, and Lika-ijust-300 from New Japan Chemical Co., Ltd., and Millad NX8000J from Milliken Corporation, but the present invention is not limited to these examples.

[0048] (resin film) In the resin film according to the present disclosure, the mass ratio of the optical adjuster, which is a diacetal compound, to the amorphous resin is preferably 1% by mass or more, more preferably 5% by mass or more, from the viewpoint of allowing the optical adjuster to exist in a crystalline or aggregated state and enhancing the dispersibility of the crystalline or aggregated diacetal compound. From the viewpoint of maintaining dispersibility and forming a film, it is preferably 20% by mass or less, more preferably 10% by mass or less. At least a portion of the optical adjuster contained in the resin film according to the present disclosure exists in the film as a crystalline or aggregated state. The diacetal compound is typically fibrous crystal or aggregated, and may include crystals with a high aspect ratio, such as needle-shaped crystals, columnar crystals, or plate-shaped crystals. The diacetal compound adjusts birefringence in the negative direction.

[0049] The precipitation of diacetal compounds in a resin film can be confirmed, for example, by the following method. Specifically, the resin film is cryo-cut (-125°C) using a cryomicrotome (using a diamond knife) in a Leica EM UC7 / FC7 (Leica Microsystems) cryosectioning system as a pretreatment device to prepare ultrathin sections approximately 100 nm thick. The obtained sections are exposed to a RuO vapor atmosphere (room temperature) for 20 minutes and stained. The presence of diacetal compounds can be confirmed in images of the stained sections taken with a transmission electron microscope (TEM). For example, a field-emission transmission electron microscope (FE-TEM) JEM-F200 (JEOL Ltd.) can be used as the TEM, and images can be taken at an accelerating voltage of 200 kV. Note that the equipment and conditions used are merely examples and are not limited thereto. In the resin film according to the present disclosure, a TEM image shows that a plurality of crystals or associations of the diacetal compound in the form of elongated fibers are present, and these crystals or associations may be positioned in random directions and intersect to form a network (mesh). The crystals or associations of the diacetal compound may also be oriented in the flow direction. The presence of crystals or associations in the film can also be confirmed by measuring the viscoelasticity of the film using a rheometer.

[0050] The birefringence of the resin film according to the present disclosure is not particularly limited. For example, if the base resin is a cycloolefin copolymer or a cycloolefin polymer, the birefringence is −5.0×10 -4 ~5.6×10 -4 If the base resin is a polycarbonate resin, the range may be -2.0 × 10 -4 ~1.4×10 -4 may be in the range of

[0051] The transparency of the resin film according to the present disclosure is measured using a haze meter. The resin film according to the present disclosure preferably has a haze value of 0.5 or less when the resin film is 80 μm thick, and more preferably has a haze value of 0.2 or less when the resin film is 40 μm thick. When the haze value is within this range, the resin film can be evaluated as transparent, and the resin film according to the present disclosure can be used in applications where transparency is required.

[0052] The thickness of the resin film according to the present disclosure can be appropriately selected depending on the application and is not particularly limited, but may be, for example, about 5 to 500 μm, and preferably about 10 to 200 μm. The resin film according to the present disclosure has high transparency even in a relatively thick film of about 100 μm (0.1 mm).

[0053] The resin film according to the present disclosure may have controlled wavelength dispersion. For example, the resin film according to the present disclosure may have stronger wavelength dispersion than a similar resin film that does not contain an optical adjuster. In this case, the resin film according to the present disclosure may be suitably used for applications requiring strong wavelength dispersion (for example, decorative films, reflective sheets, retardation films, etc.).

[0054] Furthermore, the resin film according to the present disclosure may have wavelength dispersion properties equivalent to those of the same type of resin film that does not contain an optical adjuster. In other words, it is also preferable that the wavelength dispersion of the base resin does not change even when an optical adjuster is added. This is useful when it is desired to use a film in which the birefringence is adjusted in the negative direction while maintaining the wavelength dispersion properties of the base resin film. Such a film can be used, for example, as a display film (more specifically, for example, a film for a display for VR / AR, a film for a foldable display, or a film for a rollable display).

[0055] Furthermore, the resin film according to the present disclosure may have a reverse wavelength dispersion compared to the same type of resin film that does not contain an optical adjuster. That is, the resin film that does not contain an optical adjuster may have a wavelength dispersion (a property in which birefringence decreases from the short wavelength side to the high wavelength side), and a film to which an optical adjuster is added may have a reverse wavelength dispersion (a property in which birefringence increases from the short wavelength side to the high wavelength side). In this case, the resin film according to the present disclosure may be suitably used, for example, as a retardation film.

[0056] The resin film according to the present disclosure may contain, in addition to the amorphous resin and optical adjuster (diacetal compound), additives such as stabilizers, antioxidants, ultraviolet absorbers, antistatic agents, foaming agents, lubricants, fillers, colorants, and plasticizers, as needed, as long as the effects according to the present disclosure are exhibited.

[0057] The resin film of the present invention has adjusted birefringence and transparency, and therefore can be suitably used as an optical film such as a polarizing plate protective film or a retardation film used in a liquid crystal display. This film can be applied to advanced displays such as organic electroluminescence (EL) and 3D displays, pickup lenses, etc.

[0058] (Method of manufacturing resin film) The resin film according to the present disclosure is obtained by mixing an amorphous resin and an optical adjuster, heating the mixture to a first temperature that is equal to or higher than the softening temperature of the amorphous resin but lower than the decomposition temperature of the amorphous resin, and molding the mixture using a specific method. The production method includes the steps of: heating and mixing an amorphous resin having positive birefringence with a diacetal compound represented by formula (1) at a temperature equal to or higher than the softening point of the amorphous resin to dissolve the diacetal compound in the amorphous resin to obtain a resin composition; molding the resin composition into a film; molding the resin composition at a temperature equal to or higher than the glass transition point of the amorphous resin while applying a shear force; and cooling the resin composition while applying a shear force.

[0059] In the process of obtaining the resin composition, the amorphous resin and the optical adjuster may be mixed and then heated to a temperature equal to or higher than the softening temperature of the amorphous resin and equal to or lower than the decomposition temperature of the amorphous resin. Alternatively, the amorphous resin may be heated to the aforementioned temperature range, and then the optical adjuster may be added and mixed thereto. The latter method is preferred from the viewpoint of obtaining a uniform film while maintaining a crystalline or associated state in the resin film.

[0060] A mixture of an amorphous resin and an optical adjuster is heated to a temperature above the softening temperature of the amorphous resin to dissolve the optical adjuster in the molten amorphous resin. The softened amorphous resin functions as a solvent for the optical adjuster. That is, in the molten state, the optical adjuster is believed to be dissolved in the amorphous resin. This molten mixture is preferably stirred, kneaded, or other known means to uniformly disperse the optical adjuster in the amorphous resin. Alternatively, the amorphous resin and the optical adjuster may be mixed by solvent mixing (solution casting).

[0061] The method of the present disclosure includes a step of molding the resin composition while applying a shear force at a temperature equal to or higher than the glass transition temperature of the amorphous resin. Before or after this step, the resin composition may be temporarily molded into a film by pressing, extrusion molding, injection molding, or the like.

[0062] The resin composition can be molded into a film by, for example, extruding the resulting resin composition and then cooling it. The molding can be carried out by a general method for producing a composite material made of a thermoplastic resin, and is not particularly limited. Examples of production equipment that can be used include a single-screw extruder, a twin-screw extruder, a Banbury mixer, and a roll kneader.

[0063] Next, the resulting resin composition (which may be molded) is heated to a temperature equal to or higher than the glass transition point of the amorphous resin to form a molten resin composition, which is then molded while applying a shear force to the resin composition. The shear force is not limited as long as the effects of the present disclosure can be obtained, but for example, when the thickness of the resin composition before molding is 500 μm, the shear force can be applied at about 150 to 230°C. The shear rate is also not limited as long as the effects of the present disclosure can be obtained, but for example, it can be 0.01 to 1000 s -1 In the production method according to the present disclosure, the resin composition is molded by applying a shear force while being heated to a temperature equal to or higher than the glass transition point, whereby the diacetal compound is oriented in a form having negative birefringence and precipitates from the base resin.

[0064] Next, the film is cooled while the shear force is applied. By cooling while the shear force is applied, the diacetal compound is oriented in a fibrous form, and the diacetal compound precipitates in the film. [Example]

[0065] Next, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples.

[0066] [Example 1] A cycloolefin resin (COP, Arton D4000, manufactured by JSR Corporation, glass transition temperature approximately 159°C) and 1,3:2,4-bis-O-(3,4-dimethylbenzylidene)-D-sorbitol (BDMDS, manufactured by New Japan Chemical Co., Ltd.) were mixed in a weight ratio of 97:3 using an internal mixer (Labo Plastomill Model 10S100, manufactured by Toyo Seiki Seisakusho Co., Ltd.). The raw materials were first added at 220°C and 5 rpm for 5 minutes, and then mixed at the same temperature for 5 minutes at 30 rpm to obtain a resin composition. The mixture was vacuum dried at 60°C for 3 hours before mixing. The obtained resin composition was pressed at 280°C and 4 MPa for 2 minutes using a manual hydraulic heating press (Model IMS-481E, manufactured by Imoto Machinery Co., Ltd.). It was then cooled at 25°C for 2 minutes to obtain a film with a thickness of approximately 500 µm. The obtained film was evaluated as follows. The glass transition temperature was determined by measuring E'' (loss modulus) by dynamic viscoelasticity, and the peak top was taken as the glass transition temperature. The glass transition temperature of the resin composition of Example 1 was 150°C.

[0067] <Measurement and calculation of birefringence using a polarizing microscope> The obtained film was placed on a hot stage equipped with a shear function attached to a polarizing microscope and heated to 240°C. -1 The sample was cooled to 190°C at a rate of 10°C / min while applying a shear force of 10°C / min, during which the light transmittance (DLI) was measured using a crossed polarizer system. A color filter was installed in the photodetector. The gap between the parallel circular plates was set to 500 μm. The DLI obtained in the measurement was used to calculate the birefringence Δn according to the following formula.

number

[0068] <Shear stress measurement> Shear stress was measured using a rheometer (Anton Paar, Model 302e). Parallel plates were used, with a gap between the plates of 1 mm. In the steady flow measurement, the shear stress was 190°C, the shear rate was 1 s -1 Measurement was carried out at.

[0069] <Calculation of stress optical coefficient> The stress optical coefficient (C) was calculated using the following formula from the birefringence Δn calculated using a polarizing microscope and the shear stress (σ) calculated using a rheometer. R ) was calculated. C R [×10 -9 Pa -1 ]=Δn[×10 4 ] / σ[Pa]

[0070] <Confirmation of precipitation> Because the viscoelastic properties differ between films containing diacetal compounds in a crystalline or aggregated state and films containing diacetal compounds without a crystalline or aggregated state, precipitation was confirmed using a rheometer (Anton Paar, Model 302e). Parallel plates were used with a 1 mm gap between the plates, and measurements were taken at 200°C for frequency-dependent measurements. The results were plotted with angular frequency (logω) on the horizontal axis and storage modulus (logG') on the vertical axis. The slope (logG' / logω) was calculated from the logG' values ​​when logω ranged from 0 to -1. Precipitation was evaluated as "Good" when the ratio of logG' / logω of the film containing the diacetal compound to the logG' / logω of the film consisting of only the base resin (referred to as "logG' / logω ratio" in the table) was 0.8 or less.

[0071] [Example 2] A resin composition was obtained in the same manner as in Example 1, except that the weight ratio of the cycloolefin resin to 1,3:2,4-bis-O-(3,4-dimethylbenzylidene)-D-sorbitol was 96:4. Then, a film was produced in the same manner as in Example 1. The glass transition temperature of the resin composition of Example 2 was 148°C. The obtained film was evaluated in the same manner as in Example 1.

[0072] [Example 3] A resin composition was obtained in the same manner as in Example 1, except that the weight ratio of the cycloolefin resin to 1,3:2,4-bis-O-(3,4-dimethylbenzylidene)-D-sorbitol was 95:5. Then, a film was produced in the same manner as in Example 1. The glass transition temperature of the resin composition of Example 3 was 145°C. The obtained film was evaluated in the same manner as in Example 1.

[0073] [Example 4] A resin composition was obtained in the same manner as in Example 1, except that the weight ratio of the cycloolefin resin to 1,3:2,4-bis-O-(3,4-dimethylbenzylidene)-D-sorbitol was 90:10. Then, a film was produced in the same manner as in Example 1. The glass transition temperature of the resin composition of Example 4 was 145°C. The obtained film was evaluated in the same manner as in Example 1. After measuring the birefringence using a polarizing microscope, frozen sections were prepared from the film using the method described above and observed using a TEM. The TEM image is shown in Figure 1. As shown in Figure 1, it was confirmed that the diacetal compound had precipitated in the film and was oriented in the flow direction.

[0074] [Example 5] A resin composition was obtained in the same manner as in Example 1, except that 1,3:2,4-bis-O-(4-propylbenzylidene)-D-sorbitol (BPMN, Millad NX8000J, manufactured by Milliken) was used as the diacetal compound instead of 1,3:2,4-bis-O-(3,4-dimethylbenzylidene)-D-sorbitol. The glass transition temperature of the resin composition of Example 5 was 150°C. The obtained resin composition was pressed at 280°C and 4 MPa for 2 minutes using a manual hydraulic heating press (Model IMS-481E, manufactured by Imoto Machinery Co., Ltd.). It was then cooled at 25°C for 2 minutes to obtain a film with a thickness of approximately 500 μm. The obtained film was evaluated in the same manner as in Example 1.

[0075] [Example 6] A resin composition was obtained in the same manner as in Example 5, except that the weight ratio of the cycloolefin resin to 1,3:2,4-bis-O-(4-propylbenzylidene)-D-sorbitol was 90:10. The glass transition temperature of the resin composition of Example 6 was 133°C. A film was produced in the same manner as in Example 1 and evaluated.

[0076] [Comparative Example 1] A resin composition was prepared in the same manner as in Example 1, except that the diacetal compound was not mixed, and a film having a thickness of approximately 500 μm was obtained in the same manner. The glass transition temperature of the resin composition of Comparative Example 1 was 159° C. Evaluation was performed in the same manner as in Example 1.

[0077] Table 1 shows the configurations and evaluation results of Examples 1 to 6 and Comparative Example 1. The criteria for ◯ (good) and ⊚ (very good) were as follows. ○ (Good): Δn value is 5.6 or less and 0 or more, and stress optical coefficient is 3.7 or less and 0 or more. ◎ (Very good): The Δn value is a negative value and the stress optical coefficient is a negative value.

[0078] [Table 1]

[0079] As shown in Table 1, in Examples 1 to 6, the diacetal compound was present in the film in a crystalline or aggregated state, and resin films were obtained in which the birefringence was changed in a more negative direction than in Comparative Example 1, which did not contain the diacetal compound. When comparing the Δn values ​​of Examples 1 to 4 and Comparative Example 1, increasing the amount of diacetal compound added resulted in a greater change in birefringence in the negative direction. Furthermore, increasing the amount added also resulted in a change in the stress-optical coefficient in the negative direction. In particular, in Example 4, the birefringence and applied optical coefficient became negative. Similar results were confirmed when Examples 5 and 6 were compared with Comparative Example 1. It was confirmed that modified cycloolefin polymers containing diacetal compounds increased Δn more negatively and lowered the stress-optical coefficient depending on the additive concentration.

[0080] <Measurement and calculation of chromatic dispersion> Test specimens were obtained by cutting each of the films of Example 1 and Comparative Example 1 into strips of 10 × 20 mm. The temperature was set so that the log E' (Pa) value in dynamic viscoelasticity measurement was 8.5 (Pa), and the test specimens for measurement were placed in a tensile machine (model DVE-3 S1000; manufactured by UBM Co., Ltd.). The initial distance between the clamps was 10 mm, and the test specimens were subjected to 0.1 s -1 The film was stretched at a strain rate of 1.5 times. The film stretched to 1.5 times was immediately quenched by blowing cold air onto it to obtain a test piece for wavelength dispersion measurement. Wavelength dispersion was measured using a retardation measurement device (model KOBRA-WPR, manufactured by Oji Scientific Instruments Co., Ltd.). The retardation (R449.9nm, R498.0nm, R548.0nm, R588.8nm, R628.8nm, R751.0nm) at each measurement wavelength (449.9nm, 498.0nm, 548.0nm, 588.8nm, 628.8nm, 751.0nm) was measured. The retardation measured at each wavelength was divided by the thickness of the stretched film to calculate the birefringence (Δn) at each wavelength. The birefringence (Δn) at each wavelength and the birefringence at a wavelength of 588.8nm (Δn 588.8nm ) and the ratio (Δn / Δn 588.8nm ) was calculated.

[0081] The measurement results of wavelength dispersion for Example 1 and Comparative Example 1 are summarized in Table 2.

[0082] [Table 2]

[0083] As shown in Table 2, the film of Example 1 exhibited wavelength dispersion properties equivalent to those of Comparative Example 1, which was composed only of a cycloolefin resin. In other words, the wavelength dispersion properties did not change depending on whether or not an optical adjuster was added.

[0084] [Example 7] A weight ratio of bisphenol A-polycarbonate resin (Iupilon H-3000R, manufactured by Mitsubishi Chemical Corporation, glass transition temperature approximately 153°C) to 1,3:2,4-bis-O-(3,4-dimethylbenzylidene)-D-sorbitol (BDMDS, manufactured by New Japan Chemical Co., Ltd.) was adjusted to 99:1, and the mixture was kneaded using an internal mixer (Labo Plastomill Model 10S100, manufactured by Toyo Seiki Seisakusho Co., Ltd.). The raw materials were first added at 200°C and 5 rpm for 5 minutes, and then kneaded at the same temperature for 5 minutes at 30 rpm to obtain a resin composition. The mixture was vacuum dried at 60°C for 3 hours before kneading. The obtained resin composition was pressed at 220°C and 10 MPa for 2 minutes using a manual hydraulic heating press (Model IMS-481E, manufactured by Imoto Machinery Co., Ltd.). It was then cooled at 25°C for 2 minutes to obtain a film with a thickness of approximately 500 μm. The obtained film was evaluated as follows. The glass transition temperature of the obtained resin composition was measured in the same manner as in Example 1. The glass transition temperature of the resin composition of Example 7 was 144°C.

[0085] The obtained film was evaluated in the same manner as in Example 1. However, in the measurement of birefringence using a polarizing microscope, the cooling (cooling down) start temperature was 220°C and the shear rate was 0.1 s -1 In addition, the temperature of the rheometer was set to 180°C in the measurement of shear stress. In addition, to check for precipitation, the slope (logG' / logω) was calculated from the logG' value when the logω ranged from -1 to -2. When the ratio of logG' / logω of the film containing the diacetal compound to the logG' / logω of the film consisting only of the base resin (shown as "logG' / logω ratio" in the table) was 0.8 or less, precipitation was evaluated as "Good."

[0086] [Example 8] A resin composition was obtained in the same manner as in Example 7, except that the weight ratio of polycarbonate resin to BDMDS was 95:5. Then, a film was produced in the same manner as in Example 7. The glass transition temperature of the resin composition of Example 8 was 143°C. The obtained film was evaluated in the same manner as in Example 7.

[0087] [Example 9] A resin composition was obtained in the same manner as in Example 7, except that 1,3:2,4-bis-O-(4-methylbenzylidene)-D-sorbitol (BMDS, manufactured by New Japan Chemical Co., Ltd.) was used as the diacetal compound instead of BDMDS. Then, a film was produced in the same manner as in Example 7. The glass transition temperature of the resin composition of Example 9 was 148°C. The obtained film was evaluated in the same manner as in Example 7.

[0088] Comparative Example 2 A resin composition was prepared in the same manner as in Example 7, except that the diacetal compound was not mixed, and a film having a thickness of approximately 500 μm was obtained in the same manner. Evaluations were performed in the same manner as in Example 7. The glass transition temperature of the resin composition of Comparative Example 2 was 153°C.

[0089] Table 3 shows the configurations and evaluation results of Examples 7 to 9 and Comparative Example 2. The criteria for ◯ (good) and ⊚ (very good) were as follows. ○ (Good): Δn value is 1.4 or less and 0 or more, and stress optical coefficient is 2.2 or less and 0 or more. ◎ (Very good): The Δn value is a negative value and the stress optical coefficient is a negative value.

[0090] [Table 3]

[0091] As shown in Table 3, in Examples 7 to 9, the diacetal compound was present in the film in a crystalline or aggregated state, resulting in resin films with birefringence that was more negative than that of Comparative Example 2, which did not contain the diacetal compound. Comparing the Δn values ​​of Examples 7 to 8 and Comparative Example 2, increasing the amount of diacetal compound added resulted in a greater negative change in birefringence. Furthermore, increasing the amount of diacetal compound added also resulted in a negative change in the stress-optical coefficient. In particular, in Example 8, the birefringence and applied optical coefficient became negative. It was confirmed that bisphenol A-polycarbonate polymers containing diacetal compounds increased the Δn value more negatively and lowered the stress-optical coefficient depending on the additive concentration.

[0092] The wavelength dispersion was measured by the above-mentioned method for the films of Example 7 and Comparative Example 2. The measurement results of wavelength dispersion are summarized in [Table 4].

[0093] [Table 4]

[0094] As shown in Table 4, the film of Example 7 exhibited reverse wavelength dispersion (the property of birefringence increasing from the short wavelength side to the high wavelength side), whereas Comparative Example 2, which was composed only of bisphenol A-polycarbonate polymer, exhibited wavelength dispersion (the property of birefringence decreasing from the short wavelength side to the high wavelength side). In other words, a film with reverse wavelength dispersion was obtained by adding an optical adjuster to the polycarbonate polymer.

[0095] [Example 10] A weight ratio of amorphous polyethylene terephthalate resin (Vylon 200, manufactured by Toyobo MC Co., Ltd., glass transition temperature approximately 79°C) to 1,3:2,4-bis-O-(4-methylbenzylidene)-D-sorbitol (BMDS, manufactured by New Japan Chemical Co., Ltd.) was adjusted to 95:5, and the mixture was kneaded using an internal mixer (Labo Plastomill Model 10S100, manufactured by Toyo Seiki Seisakusho Co., Ltd.). The raw materials were first added at 240°C and 5 rpm for 3 minutes, and then kneaded at the same temperature and 50 rpm for 3 minutes to obtain a resin composition. The mixture was vacuum dried at 70°C for 4 hours before kneading. The obtained resin composition was pressed at 250°C and 10 MPa for 1 minute using a manual hydraulic heating press (Model IMS-481E, manufactured by Imoto Machinery Co., Ltd.). It was then cooled at 25°C for 2 minutes to obtain a film with a thickness of approximately 1 mm. The obtained film was evaluated as follows. The glass transition temperature of the obtained resin composition was measured in the same manner as in Example 1. The glass transition temperature of the resin composition of Example 10 was 77°C.

[0096] The obtained film was evaluated in the same manner as in Example 1. However, in the measurement of birefringence using a polarizing microscope, the cooling (cooling down) starting temperature was 240°C and the shear rate was 0.1 s -1 In addition, the temperature of the rheometer was set to 90°C when measuring the shear stress. In addition, to check for precipitation, the slope (logG' / logω) was calculated from the logG' value when the logω ranged from 0 to -1. When the ratio of logG' / logω of a film containing a diacetal compound to logG' / logω of a film consisting only of a base resin (shown as "logG' / logω ratio" in the table) was 0.9 or less, precipitation was evaluated as "Good."

[0097] [Example 11] A resin composition was obtained in the same manner as in Example 10, except that the weight ratio of amorphous polyethylene terephthalate resin to BMDS was 90:10. Then, a film was produced in the same manner as in Example 10. The glass transition temperature of the resin composition of Example 11 was 75°C. The obtained film was evaluated in the same manner as in Example 10.

[0098] [Example 12] A resin composition was obtained in the same manner as in Example 10, except that 1,3:2,4-bis-O-(3,4-dimethylbenzylidene)-D-sorbitol (BDMDS, manufactured by New Japan Chemical Co., Ltd.) was used as the diacetal compound instead of BMDS. Then, a film was produced in the same manner as in Example 10. The glass transition temperature of the resin composition of Example 12 was 78°C. The obtained film was evaluated in the same manner as in Example 10.

[0099] Comparative Example 3 A resin composition was prepared in the same manner as in Example 10, except that the diacetal compound was not mixed, and a film having a thickness of approximately 1 mm was obtained in the same manner. Evaluation was performed in the same manner as in Example 10. The glass transition temperature of the resin composition of Comparative Example 3 was 79°C.

[0100] Table 5 shows the configurations and evaluation results of Examples 10 to 12 and Comparative Example 3. The criteria for ◯ (good) and ⊚ (very good) were as follows. ○ (Good): Δn value is 0 or more and 4.0 or less, and stress optical coefficient is 0 or more and 2.0 or less. ◎ (Very good): The Δn value is a negative value and the stress optical coefficient is a negative value.

[0101] [Table 5]

[0102] As shown in Table 5, in Examples 10 to 12, the diacetal compound was present in the film in a crystalline or aggregated state, and resin films were obtained in which the birefringence was changed in a more negative direction than in Comparative Example 3, which did not contain the diacetal compound. When comparing the Δn values ​​of Examples 10 to 12 and Comparative Example 3, increasing the amount of diacetal compound added resulted in a greater change in the birefringence in the negative direction. Furthermore, increasing the amount of diacetal compound added also resulted in a change in the stress-optical coefficient in the negative direction. In particular, in Example 11, the birefringence and applied optical coefficient became negative. It was confirmed that amorphous polyethylene terephthalate resins containing diacetal compounds increased Δn in the negative direction and lowered the stress-optical coefficient depending on the concentration of the additive.

[0103] The wavelength dispersion was measured by the above-mentioned method for the films of Example 10 and Comparative Example 3. The measurement results of wavelength dispersion are summarized in [Table 6].

[0104] [Table 6]

[0105] As shown in Table 6, the film of Example 10 exhibited reverse wavelength dispersion (the property of birefringence increasing from the short wavelength side to the high wavelength side), whereas Comparative Example 3, which was composed only of amorphous polyethylene terephthalate polymer, exhibited wavelength dispersion (the property of birefringence decreasing from the short wavelength side to the high wavelength side). In other words, a reverse wavelength dispersion film was obtained by adding an optical adjuster to amorphous polyethylene terephthalate polymer.

[0106] The present invention is intended to cover a wide range of applications, including those related to the present invention, including those related to the present invention.

Claims

1. an amorphous resin having positive birefringence; a diacetal compound represented by formula (1); A film comprising: In the film, the diacetal compound is precipitated as crystals or in an aggregated state exhibiting negative birefringence. Resin film for optical films. 【Chemistry 1】 (In the formula, R １ , R ２ , R ３ , R ４ , R ５ and R ６ are the same or different and each represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, an alkoxycarbonyl group having 1 to 4 carbon atoms, a halogenated alkyl group having 1 to 4 carbon atoms, or a halogen atom. ７ represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkenyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, an alkoxycarbonyl group having 1 to 4 carbon atoms, or a halogenated alkyl group having 1 to 4 carbon atoms.

2. The diacetal compound is contained in an amount of 1% by mass or more and 20% by mass or less relative to the amorphous resin. The resin film for optical films according to claim 1 .

3. the amorphous resin is a resin containing at least one selected from the group consisting of a cycloolefin resin, a polycarbonate resin, and a polyester resin; The resin film for optical films according to claim 1 .

4. a step of heating and mixing an amorphous resin having positive birefringence and a diacetal compound represented by formula (1) at a temperature equal to or higher than the softening point of the amorphous resin to dissolve the diacetal compound in the amorphous resin, thereby obtaining a resin composition; a step of heating the resin composition to form it into a molten state while applying a shear force; a step of cooling the mixture while applying a shear force continuously from the molding step; Including, The method for producing a resin film for an optical film, wherein the diacetal compound is precipitated as a crystal or in an associated state, and the diacetal compound adjusts birefringence in a negative direction. 【Chemistry 2】 (In the formula, R １ , R ２ , R ３ , R ４ , R ５ and R ６ are the same or different and each represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, an alkoxycarbonyl group having 1 to 4 carbon atoms, a halogenated alkyl group having 1 to 4 carbon atoms, or a halogen atom. ７ represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkenyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, an alkoxycarbonyl group having 1 to 4 carbon atoms, or a halogenated alkyl group having 1 to 4 carbon atoms.

5. the diacetal compound precipitates as crystals or in an associated state in the resin film for an optical film and is oriented in the flow direction, The diacetal compound adjusts birefringence in the negative direction. The method for producing the resin film for optical films according to claim 4 .

Images