Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B27/00—Layered products comprising a layer of synthetic resin
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B27/00—Layered products comprising a layer of synthetic resin
  • B32B27/18—Layered products comprising a layer of synthetic resin characterised by the use of special additives
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
  • B32B7/02—Physical, chemical or physicochemical properties
  • B32B7/023—Optical properties
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
  • B32B7/04—Interconnection of layers
  • B32B7/12—Interconnection of layers using interposed adhesives or interposed materials with bonding properties
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B1/00—Optical elements characterised by the material of which they are made; Optical coatings for optical elements
  • G02B1/10—Optical coatings produced by application to, or surface treatment of, optical elements
  • G02B1/14—Protective coatings, e.g. hard coatings
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B5/00—Optical elements other than lenses
  • G02B5/30—Polarising elements

Definitions

• the present invention relates to an optical film, an optical film manufacturing method, an optical member, and an image display device.
• Liquid crystal display devices and organic EL display devices are used for various image displays such as monitors and televisions.
• a polarizing plate is used in a liquid crystal display device.
• a polarizing plate and a quarter-wave plate are used in an organic EL display device to prevent reflection of external light.
• a polarizing plate usually includes a polarizer and a polarizer protective film attached to at least one surface of the polarizer via an adhesive layer.
• cellulose-based films have been widely used as polarizer protective films.
• films made of acrylic, polyester, polycarbonate, cyclic polyolefin, etc. are also used. These films have lower moisture permeability than cellulose-based films and are superior in durability, but the adhesiveness between these films and PVA-based polarizers is inferior to that of cellulose-based films.
• a method has been proposed in which an easy-adhesion layer is provided on the surface of these films to improve the adhesion between the film and the polarizer.
• Patent Document 1 describes that by providing an easy-adhesion layer containing fine particles and a binder resin on the surface of an acrylic film, it is possible not only to improve the adhesion between the acrylic film and the polarizer but also to suppress blocking.
• Patent Document 2 discloses that the easy-adhesion layer contains alkali components such as ammonia and amines, and that the excess alkali components remaining in the easy-adhesion layer degrade the polarizer, but the alkali component is a binder resin (precursor ), and that the alkali component improves the dispersibility of the inorganic fine particles present in the easy-adhesion layer. It is described that by heating after coating the easy-adhesion composition on the film substrate, the alkali component can be volatilized and removed, and the residual alkali component in the easy-adhesion layer can be reduced.
• alkali components such as ammonia and amines
• An optical member comprising the optical film according to any one of [1] to [6].
• An image display device comprising the optical film according to any one of [1] to [6].
• a coating film of the easy-adhesion composition is formed, and the coating film is dried to form an easy-adhesion layer containing the binder resin, the polyamine, and the fine particles on the surface of the resin film, and the polyamine comprises a plurality of wherein the plurality of amino groups includes at least one selected from the group consisting of secondary amino groups and tertiary amino groups.
• the optical film of the present invention has a resin film and an easy-adhesion layer, and has excellent adhesion therebetween.
• the alkaline component contained in the easy-adhesion layer is a polymer that hardly volatilizes during the production of the optical film, so the amount of alkali component contained in the easy-adhesion layer can be easily controlled.
• resin in this specification is a broader concept than “polymer”.
• the resin may be composed of, for example, one or two or more polymers, and if necessary, materials other than polymers, such as UV absorbers, antioxidants, additives such as fillers, and compatibilizers. , stabilizers and the like.
• optical film has a resin film and an easy-adhesion layer formed on the surface of the resin film.
• the resin film is not particularly limited, but is a film made of a material such as (meth)acrylic polymer, polyester, polycarbonate, cyclic polyolefin, or the like.
• a material such as (meth)acrylic polymer, polyester, polycarbonate, cyclic polyolefin, or the like.
• an acrylic resin film obtained by molding an acrylic resin containing a (meth)acrylic polymer is preferable.
• the content of the (meth)acrylic polymer in the acrylic resin is usually 30% by weight or more, preferably 50% by weight or more, more preferably 70% by weight or more, particularly preferably 90% by weight or more, and most preferably 95% by weight. That's it.
• a (meth)acrylic polymer is a polymer having structural units ((meth)acrylic acid ester units) derived from (meth)acrylic acid ester monomers.
• the (meth)acrylate unit content in the (meth)acrylic polymer is usually 10% by weight or more, preferably 30% by weight or more, more preferably 50% by weight or more, and particularly preferably 70% by weight or more.
• the weight average molecular weight of the (meth)acrylic polymer is preferably 10,000 to 500,000, more preferably 50,000 to 300,000.
• (Meth) acrylic acid ester units for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, n-butyl (meth) acrylate, t- (meth) acrylate Butyl, n-hexyl (meth)acrylate, cyclohexyl (meth)acrylate, benzyl (meth)acrylate, chloromethyl (meth)acrylate, 2-chloroethyl (meth)acrylate, 2-hydroxy (meth)acrylate each unit of ethyl, 3-hydroxypropyl (meth)acrylate, 2,3,4,5,6-pentahydroxyhexyl (meth)acrylate, and 2,3,4,5-tetrahydroxypentyl (meth)acrylate; It is a structural unit derived from a mer.
• the (meth)acrylic polymer preferably has structural units derived from methyl (meth)acrylate, in which case the optical properties and thermal stability of the finally obtained optical film are improved.
• the (meth)acrylic polymer may have two or more (meth)acrylate units.
• the (meth)acrylic polymer may have structural units other than the (meth)acrylic acid ester unit.
• Such structural units are, for example, styrene, vinyltoluene, ⁇ -methylstyrene, ⁇ -hydroxymethylstyrene, ⁇ -hydroxyethylstyrene, acrylonitrile, methacrylonitrile, ethylene, propylene, 4-methyl-1-pentene, acetic acid
• the (meth)acrylic polymer may have two or more of these structural units.
• the degree of freedom in controlling wavelength dispersion of birefringence in the optical film is improved.
• the shorter the wavelength of light the smaller the birefringence (the smaller the absolute value of the retardation).
• the retardation film is suitable as a positive retardation film.
• the (meth)acrylic polymer may have a ring structure in its main chain.
• a (meth)acrylic polymer is, for example, a copolymer of a (meth)acrylic acid ester monomer and a monomer having a ring structure, or a monomer containing a (meth)acrylic acid ester monomer It is obtained by polymerizing a group of bodies followed by a cyclization reaction.
• the total content of the (meth)acrylate unit and the ring structure should be 50% by weight or more.
• the (meth)acrylic polymer is formed by copolymerization of a monomer group containing a monomer having a hydroxyl group and/or a carboxylic acid group. preferably.
• monomers having a hydroxyl group include methyl 2-(hydroxymethyl)acrylate, ethyl 2-(hydroxymethyl)acrylate, isopropyl 2-(hydroxymethyl)acrylate, butyl 2-(hydroxymethyl)acrylate, They are methyl 2-(hydroxyethyl)acrylate, methallyl alcohol, and allyl alcohol.
• Monomers with carboxylic acid groups are, for example, acrylic acid, methacrylic acid, crotonic acid, 2-(hydroxymethyl)acrylic acid, 2-(hydroxyethyl)acrylic acid. Two or more of these monomers may be used. Note that it is not necessary for all of the monomers to change to a ring structure during the cyclization reaction, even if the (meth)acrylic polymer after the cyclization reaction has structural units derived from these monomers. good.
• the (meth)acrylic polymer preferably has a ring structure in its main chain.
• the acrylic resin film is excellent in heat resistance and hardness.
• it is suitable for use as a retardation film or a polarizer protective film having the function of a retardation film.
• the ring structure is, for example, at least one selected from an N-substituted maleimide structure, maleic anhydride structure, glutarimide structure, glutaric anhydride structure and lactone ring structure.
• the N-substituted maleimide structure is, for example, a cyclohexylmaleimide structure, a methylmaleimide structure, a phenylmaleimide structure, a benzylmaleimide structure.
• the ring structure includes a lactone ring structure, a cyclic imide structure (eg, N-alkyl-substituted maleimide structure, glutarimide structure), a cyclic anhydride structure (eg, maleic anhydride structure and glutaric anhydride structure). structure).
• the optical film of this embodiment can be used as a retardation film.
• the ring structure is preferably a lactone ring structure, a glutarimide structure, or a glutaric anhydride structure from the viewpoint of imparting a positive retardation to the optical film as the retardation film.
• the ring structure is preferably a lactone ring structure.
• the glutaric anhydride structure and glutarimide structure are shown in the following general formula (1).
• R 1 and R 2 in the general formula (1) are each independently a hydrogen atom or a methyl group, and X 1 is an oxygen atom or a nitrogen atom.
• X 1 is an oxygen atom
• R 3 does not exist
• R 3 is a hydrogen atom, a linear alkyl group having 1 to 6 carbon atoms, a cyclopentyl group, a cyclohexyl group, or a benzyl group. or a phenyl group.
• the ring structure represented by general formula (1) is a glutaric anhydride structure.
• the glutaric anhydride structure can be formed, for example, by subjecting a copolymer of (meth)acrylic acid ester and (meth)acrylic acid to intramolecular dealcoholization cyclocondensation.
• X 1 is a nitrogen atom
• the ring structure represented by general formula (1) is a glutarimide structure.
• a glutarimide structure can be formed, for example, by imidating a (meth)acrylate polymer with an imidizing agent such as methylamine.
• the following general formula (2) shows the maleic anhydride structure and the N-substituted maleimide structure.
• R 4 and R 5 in the general formula (2) are each independently a hydrogen atom or a methyl group, and X 2 is an oxygen atom or a nitrogen atom.
• X 2 is an oxygen atom
• R 6 does not exist
• R 6 is a hydrogen atom, a linear alkyl group having 1 to 6 carbon atoms, a cyclopentyl group, a cyclohexyl group, or a benzyl group. or a phenyl group.
• the ring structure represented by general formula (2) is a maleic anhydride structure.
• a maleic anhydride structure can be formed, for example, by copolymerizing maleic anhydride and a (meth)acrylic acid ester.
• X 2 is a nitrogen atom
• the ring structure represented by general formula (2) is an N-substituted maleimide structure.
• the resin obtained is an acrylic resin.
• a lactone ring structure is shown in the following general formula (3).
• R 7 , R 8 and R 9 are each independently a hydrogen atom or an organic residue having 1 to 20 carbon atoms.
• the organic residue may contain an oxygen atom.
• the organic residue in the general formula (3) is, for example, an alkyl group having 1 to 20 carbon atoms such as methyl group, ethyl group or propyl group;
• An aromatic hydrocarbon group having 6 to 20 carbon atoms such as a saturated aliphatic hydrocarbon group, a phenyl group, and a naphthyl group, wherein the alkyl group, the unsaturated aliphatic hydrocarbon group, and the aromatic hydrocarbon group are , one or more hydrogen atoms may be substituted with at least one group selected from a hydroxyl group, a carboxyl group, an ether group, and an ester group.
• a six-membered lactone ring structure is shown in the general formula (3), but the lactone ring structure is not limited to this.
• the lactone ring structure may be a 4- to 8-membered ring.
• a 5- or 6-membered ring is preferable, and a 6-membered ring is more preferable, because the stability of the ring structure is excellent.
• the content of the ring structure in the polymer is not particularly limited, but is usually 5 to 90% by weight, preferably 10 to 70% by weight, and more It is preferably 10 to 60% by weight, more preferably 10 to 50% by weight.
• the ring structure content is high (for example, 10% by weight or more), the heat resistance, solvent resistance and surface hardness of the film are particularly excellent.
• the content of the ring structure is small (for example, 70% by weight or less), the easiness of stretching of the acrylic resin film and the handleability during production are particularly excellent.
• the content of the ring structure is not particularly limited, but for example 5 It is up to 90% by mass, preferably 10 to 70% by mass, more preferably 10 to 60% by mass, and still more preferably 10 to 50% by mass.
• the content of the ring structure is not particularly limited, but is, for example, 5 to 90% by mass, preferably 10 to 80% by mass, more preferably 10 to 70%. % by mass, more preferably 10 to 60% by mass.
• a (meth)acrylic polymer having a ring structure in its main chain can be formed by a known method.
• (Meth) acrylic polymers having a lactone ring structure in the main chain are, for example, JP-A-2000-230016, JP-A-2001-151814, JP-A-2002-120326, JP-A-2002-254544, It is a polymer described in JP-A-2005-146084 and can be formed by the method described therein.
• the (meth)acrylic polymer having a glutaric anhydride structure in the main chain is, for example, a polymer described in JP-A-2006-283013, JP-A-2006-335902, and JP-A-2006-274118. Yes, and can be formed by the method described in the publication.
• (Meth)acrylic polymers having a glutarimide structure in the main chain are, for example, JP-A-2006-309033, JP-A-2006-317560, JP-A-2006-328329, JP-A-2006-337491, JP-A-2006-337492, JP-A-2006-337493, JP-A-2006-337569, the polymer described in JP-A-2007-009182, the It can be formed by the method described in the publication.
• the monomer raw material, auxiliary raw materials such as polymerization initiators and catalysts, and solvents used for polymerization should be filtered as much as possible before use. It is preferable from the viewpoint of reducing foreign substances in the polymer and because it can be filtered at a stage of low viscosity rather than filtering after polymerization.
• a method of filtration if it is a liquid, it may be directly dissolved, and if it is a solid, it may be dissolved in a solvent or the like used for polymerization and then passed through various filters such as a membrane filter and a hollow fiber membrane filter. , as a mixture and then filtered.
• the filtration accuracy at this time is preferably 5.0 ⁇ m or less, more preferably 1.0 ⁇ m or less, and still more preferably 0.5 ⁇ m or less.
• the acrylic resin may be composed of a combination of a (meth)acrylic polymer and another polymer, depending on desired physical properties and applications.
• the other polymer is not particularly limited, and may be a thermoplastic polymer, a curable polymer, or a combination thereof. Other polymers may be used alone or in combination of two or more.
• the other polymer examples include another (meth)acrylic polymer having a different composition ratio or molecular weight from the (meth)acrylic polymer, or having a different copolymerization composition, or an olefin polymer (e.g., polyethylene, polypropylene, ethylene - propylene copolymers, poly (4-methyl-1-pentene), etc.), halogen-based polymers (e.g., halogenated vinyl polymers such as polyvinyl chloride, polyvinylidene chloride, and polyvinyl chloride), styrene-based polymers [e.g.,
• polystyrene, styrenic copolymer e.g., styrene-methyl methacrylate copolymer, styrene-acrylonitrile copolymer, acrylonitrile-butadiene-styrene block copolymer (ABS resin), acrylate-styrene-acrylonitrile copolymer (ASA resin), etc.
• polyester polymers e.g., aromatic polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate
• polyamide polymers e.g., aliphatic polyamides such as polyamide 6, polyamide 66, and polyamide 610 polyacetal-based polymer, polycarbonate-based polymer, polyphenylene oxide-based polymer, polyphenylene sulfide-based polymer, polyetheretherketone-based polymer, polysulfone-based polymer, polyethersulfone-based polymer, poly
• the existence form of the (meth)acrylic polymer and the other polymer is not particularly limited, and may be a polymer blend, The above-mentioned (meth)acrylic polymer and other polymer may be chemically bonded. In this case, a block copolymer, a graft copolymer, or the like may be formed from the (meth)acrylic polymer and another polymer.
• the content of the other polymer is, for example, 90% by mass or less (e.g., 0.1 to 85% by mass), and 80 % by mass or less (eg, 0.5 to 70% by mass), preferably 60% by mass or less (eg, 1 to 55% by mass), and 50% by mass or less (eg, 2 to 45% by mass) , 30% by mass or less (eg, 2 to 25% by mass), 20% by mass or less (eg, 2 to 15% by mass), or the like.
• 90% by mass or less e.g., 0.1 to 85% by mass
• 80 % by mass or less eg, 0.5 to 70% by mass
• 60% by mass or less eg, 1 to 55% by mass
• 50% by mass or less eg, 2 to 45% by mass
• 30% by mass or less eg, 2 to 25% by mass
• 20% by mass or less eg, 2 to 15% by mass
• the acrylic resin contains a styrene-based polymer
• the positive retardation exhibited by the (meth)acrylic polymer having a ring structure in the main chain is It can be canceled by the negative retardation exhibited by the styrenic polymer.
• a negative retardation film or a low retardation polarizer protective film can be obtained.
• the acrylic resin film contains a styrene-based polymer
• the styrene-based polymer is preferably a styrene-acrylonitrile copolymer from the viewpoint of compatibility with the (meth)acrylic polymer.
• the acrylic resin film contains an ABS resin or an ASA resin
• the acrylic resin film can be used as a negative retardation film or a low retardation film. Flexibility can be increased.
• the acrylic resin may contain materials other than polymers, such as additives.
• Additives include, for example, antioxidants such as hindered phenol, phosphorus, and sulfur; stabilizers such as light stabilizers, weather stabilizers, and heat stabilizers; reinforcing materials such as glass fiber and carbon fiber; UV absorbers such as tylate, (2,2'-hydroxy-5-methylphenyl)benzotriazole, 2-hydroxybenzophenone; near-infrared absorbers; Repellent; Antistatic agent composed of anionic, cationic, and nonionic surfactants; Colorants such as inorganic pigments, organic pigments, and dyes; Organic fillers, inorganic fillers; Anti-blocking agents; Resin modifiers; Fillers, inorganic fillers; plasticizers; lubricants; retardation reducers.
• antioxidants such as hindered phenol, phosphorus, and sulfur
• stabilizers such as light stabilizers, weather stabilizers, and heat stabilizers
• the content of the additive in the acrylic resin is preferably 0-5% by weight, more preferably 0-2% by weight, and even more preferably 0-0.5% by weight.
• the Tg (glass transition temperature) of the acrylic resin is preferably 100°C or higher, more preferably 110°C or higher, even more preferably 115°C or higher, and particularly preferably 120°C or higher.
• the upper limit of the Tg of the acrylic resin is not particularly limited, it is preferably 170° C. or less from the viewpoint of stretchability when made into an acrylic resin film.
• Acrylic resin film is obtained by molding acrylic resin.
• the thickness of the acrylic resin film is not particularly limited, preferably 5 to 200 ⁇ m, more preferably 10 to 100 ⁇ m. Strength is excellent in the said thickness being 5 micrometers or more. Transparency is excellent in the said thickness being 200 micrometers or less.
• the surface wetting tension of the acrylic resin film is preferably 40 mN/m or more, more preferably 50 mN/m or more, and even more preferably 55 mN/m or more.
• the surface wetting tension is 40 mN/m or more, the adhesiveness between the optical film of this embodiment and other members is further improved.
• Any appropriate surface treatment may be applied to the surface of the acrylic resin film in order to adjust the wetting tension of the surface.
• Surface treatments include, for example, corona discharge treatment, plasma treatment, ozone spraying, ultraviolet irradiation, flame treatment, and chemical treatment. Among them, corona discharge treatment and plasma treatment are preferred.
• the acrylic resin film can be formed by a known film forming method using an acrylic resin.
• Film-forming techniques include, for example, a solution casting method, a melt extrusion method, a calendering method, and a compression molding method. Among them, the solution casting method and the melt extrusion method are preferable.
• the acrylic resin used for film formation can be formed by a known method.
• an acrylic resin is formed by sufficiently mixing a (meth)acrylic polymer, other thermoplastic polymer, additives, etc., blended according to the composition of the acrylic resin to be obtained, by an appropriate mixing method. .
• the mixing method is, for example, extrusion kneading or mixing in a solution state.
• a commercially available acrylic resin may be used for film formation.
• Commercially available acrylic resins are, for example, ACRYPET VH and ACRYPET VRL20A (both manufactured by Mitsubishi Rayon). Any suitable mixer such as an omni-mixer, a single-screw extruder, a twin-screw extruder, or a pressure kneader can be used for extrusion kneading.
• a solvent used in the solution casting method is not limited as long as it dissolves the acrylic resin.
• the solvent include aromatic hydrocarbons such as benzene, toluene and xylene; aliphatic hydrocarbons such as cyclohexane and decalin; esters such as ethyl acetate and butyl acetate; ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone.
• alcohols such as methanol, ethanol, isopropanol, butanol, isobutanol, methyl cellosolve, ethyl cellosolve, butyl cellosolve; ethers such as tetrahydrofuran and dioxane; halogenated hydrocarbons such as dichloromethane, chloroform and carbon tetrachloride; be. Two or more of these solvents may be used in combination.
• the melt extrusion method is, for example, the T-die method and the inflation method.
• the molding temperature during melt extrusion is preferably 150 to 350°C, more preferably 200 to 300°C.
• a strip-shaped acrylic resin film can be formed by attaching a T-die to the tip of a known extruder.
• the strip-shaped acrylic resin film thus formed may be wound on a roll to form a film roll.
• the obtained acrylic resin film may be stretched.
• the stretching direction may be the longitudinal direction (MD direction) of the acrylic resin film, the width direction (TD direction) orthogonal to the longitudinal direction, or a direction oblique to the longitudinal direction.
• MD direction longitudinal direction
• TD direction width direction
• a direction oblique to the longitudinal direction when stretching in the biaxial direction, it may be a sequential stretching in which stretching in the MD direction (longitudinal stretching) and stretching in the TD direction (transverse stretching) are performed sequentially, or stretching in the MD direction and in the TD direction. It may be a simultaneous stretching in which the stretching is performed at the same time.
• the temperature during stretching is preferably in the range of (Tg-30) to (Tg+100)°C, more preferably in the range of (Tg-20) to (Tg+80)°C, where Tg is the glass transition temperature of the acrylic resin film. , (Tg ⁇ 5) to (Tg+20)° C. is more preferable.
• the draw ratio is not particularly limited, but may be, for example, about 1.1 to 25 times (for example, 1.3 to 10 times), which is defined as the area ratio.
• the stretching speed (one direction) is not particularly limited, but may be, for example, about 10 to 20000%/min (eg, 100 to 10000%/min).
• a stretched acrylic resin film is suitable as a retardation film.
• the stretching method is not particularly limited, and a known stretching machine can be used for stretching. A description of the drawing machine will be given later.
• the acrylic resin film is formed by melt extrusion, it is possible to continuously perform the process from the formation of the acrylic resin by mixing the materials to the formation and stretching of the acrylic resin film.
• the acrylic resin film is formed by the T-die method, it is possible to simultaneously perform uniaxial stretching in the MD direction and winding of the film by adjusting the temperature of the roll for winding the formed film.
• the acrylic resin film may be subjected to heat treatment (annealing) in order to stabilize the optical isotropy and mechanical properties of the acrylic resin film.
• heat treatment annealing
• the heat treatment method and conditions can be selected as appropriate.
• the easy-adhesion layer contains binder resin, polyamine, and fine particles.
• Polyamines are polymers with multiple amino groups. A plurality of amino groups includes at least one selected from the group consisting of secondary amino groups and tertiary amino groups.
• the polyamine content in the easy-adhesion layer is 0.0090% by weight to 1.4100% by weight. Polyamine promotes the dispersion of fine particles in the easy-adhesion layer, and improves the adhesion between the resin film and the easy-adhesion layer, the blocking resistance of the optical film, and the uniformity of the easy-adhesion layer.
• the physical properties required for optical films include retardation, tear resistance, and folding resistance.
• the stretching temperature is changed according to subtle differences in the physical properties of resin lots, such as molecular weight and composition ratio.
• changing the stretching temperature means changing the drying temperature of the easy-adhesion layer.
• the alkali component contained in the easy-adhesion layer is a low-molecular-weight compound
• changing the drying temperature of the easy-adhesion layer changes the volatilization amount of the alkali component, and the content of the alkali component in the easy-adhesion layer also changes.
• the desired effect based on the alkali component may not be sufficiently obtained. It is difficult to change the drawing temperature to keep the content of the alkali component within the desired range.
• a highly volatile low-molecular-weight alkaline component is likely to be released to the outside during the stretching process at a high temperature. In this case, the effect of accelerating the dispersion of fine particles by the alkali component becomes insufficient.
• the polymer polyamine is difficult to volatilize and can reliably remain in the easy-adhesion layer. Even if the stretching temperature is changed, the content of polyamine in the easy-adhesion layer does not easily change. Therefore, the polymer polyamine is suitable for keeping the content of the alkali component in the easy-adhesion layer within a desired range, and can certainly promote the dispersion of the fine particles. As a result, further improvement in blocking resistance of the optical film can be expected.
• the stretching temperature of the resin film ( ⁇ drying temperature of the easy-adhesion layer) is set high. It is considered that the binder resin of the easy-adhesion layer easily permeates the surface of the resin film at a temperature higher than Tg. As a result, the adhesion between the easy-adhesion layer and the resin film can be further improved.
• the binder resin may be any known resin having easy adhesion, such as urethane resin, cellulose resin, polyol resin, polycarboxylic acid resin, polyester resin, and acrylic resin. At least one selected from these resins can be used as the binder resin.
• the number average molecular weight of the binder resin is preferably 50,000 to 600,000, more preferably 10,000 to 400,000.
• the binder resin includes, for example, urethane resin.
• the binder resin is preferably urethane resin.
• the urethane resin is not particularly limited, and is typically a resin obtained by reacting a polyol and a polyisocyanate. Any polyol having two or more hydroxyl groups in the molecule can be adopted as the polyol.
• Polyols are, for example, polyacrylic polyols, polyester polyols, polyether polyols. Two or more polyols may be combined.
• a polyacrylic polyol is typically a copolymer of a (meth)acrylic acid ester monomer and a monomer having a hydroxyl group.
• (Meth)acrylate monomers are, for example, methyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and cyclohexyl (meth)acrylate.
• Examples of monomers having a hydroxyl group include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, (meth)acrylic acid hydroxyalkyl esters such as 4-hydroxybutyl (meth)acrylate and 2-hydroxypentyl (meth)acrylate; (meth)acrylic acid monoesters of polyhydric alcohols such as glycerin and trimethylolpropane; N - methylol (meth)acrylamide.
• the polyacrylic polyol may be a copolymer with other monomers.
• Other monomers are not limited as long as they can be copolymerized with the (meth)acrylic acid ester monomer and hydroxyl group-containing monomer.
• Said other monomers are, for example, unsaturated monocarboxylic acids such as (meth)acrylic acid; unsaturated dicarboxylic acids such as maleic acid and their anhydrides and mono- or diesters; unsaturated nitriles such as (meth)acrylonitrile.
• Unsaturated amides such as (meth)acrylamide and N-methylol (meth)acrylamide; Vinyl esters such as vinyl acetate and vinyl propionate; Vinyl ethers such as methyl vinyl ether; ⁇ -olefins such as ethylene and propylene; Halogenated ⁇ , ⁇ -unsaturated aliphatic monomers such as vinyl chloride and vinylidene chloride; ⁇ , ⁇ -unsaturated aromatic monomers such as styrene and ⁇ -methylstyrene.
• a polyester polyol is typically obtained by reacting a polybasic acid component and a polyol component.
• Polybasic acid components include, for example, orthophthalic acid, isophthalic acid, terephthalic acid, 1,4-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, biphenyldicarboxylic acid, tetrahydrophthalic acid, and the like.
• Aromatic dicarboxylic acids oxalic acid, succinic acid, malonic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, decanedicarboxylic acid, dodecanedicarboxylic acid, octadecanedicarboxylic acid, tartaric acid, alkylsuccinic acid, Aliphatic dicarboxylic acids such as linoleic acid, maleic acid, fumaric acid, mesaconic acid, citraconic acid and itaconic acid; alicyclic dicarboxylic acids; or reactive derivatives thereof such as acid anhydrides, alkyl esters and acid halides.
• Polyol components include, for example, ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, pentanediol, 1,6-hexanediol.
• a polyether polyol is typically obtained by adding an alkylene oxide to a polyhydric alcohol through ring-opening polymerization.
• Polyhydric alcohols are, for example, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, glycerin, trimethylolpropane.
• Alkylene oxides are, for example, ethylene oxide, propylene oxide, butylene oxide, styrene oxide, tetrahydrofuran.
• Polyisocyanates are, for example, tetramethylene diisocyanate, dodecamethylene diisocyanate, 1,4-butane diisocyanate, hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, Aliphatic diisocyanates such as 2-methylpentane-1,5-diisocyanate and 3-methylpentane-1,5-diisocyanate; isophorone diisocyanate, hydrogenated xylylene diisocyanate, 4,4′-cyclohexylmethane diisocyanate, 1,4-cyclohexane Alicyclic diisocyanates such as diisocyanate, methylcyclohexylene diisocyanate and 1,3-bis(isocyanatomethyl)cyclohexane; Aromatics such as diisocyanate, 4,4'
• the urethane resin preferably has a carboxyl group.
• a carboxyl group By having a carboxyl group, the performance (facilitated adhesion) of the easily adhesive layer is improved. This effect is particularly remarkable in a high-temperature/high-humidity environment.
• a urethane resin having a carboxyl group can be obtained, for example, by reacting a chain lengthening agent having a free carboxyl group in addition to a polyol and a polyisocyanate. Chain extenders with free carboxyl groups are, for example, dihydroxycarboxylic acids, dihydroxysuccinic acids.
• Dihydroxycarboxylic acids are, for example, dialkylolalkanoic acids such as dimethylolalkanoic acid (eg, dimethylolacetic acid, dimethylolbutanoic acid, dimethylolpropionic acid, dimethylolbutyric acid, dimethylolpentanoic acid).
• dimethylolalkanoic acid eg, dimethylolacetic acid, dimethylolbutanoic acid, dimethylolpropionic acid, dimethylolbutyric acid, dimethylolpentanoic acid.
• the acid value of the urethane resin is preferably 10 or more, more preferably 10-50, and particularly preferably 20-45. In these cases, the performance of the easy-adhesion layer (for example, adhesion with other functional films such as polarizers) is further improved.
• the urethane resin may be obtained by reacting with other polyols or other chain lengthening agents in addition to the above components.
• Other polyols are, for example, sorbitol, 1,2,3,6-hexanetetraol, 1,4-sorbitan, 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerin, trimethylolethane , trimethylolpropane, and pentaerythritol.
• chain lengthening agents are, for example, ethylene glycol, diethylene glycol, triethylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, pentanediol, 1,6- glycols such as hexanediol and propylene glycol; aliphatic diamines such as ethylenediamine, propylenediamine, hexamethylenediamine, 1,4-butanediamine and aminoethylethanolamine; lipids such as isophoronediamine and 4,4'-dicyclohexylmethanediamine Cyclic diamines; aromatic diamines such as xylylenediamine and tolylenediamine.
• Urethane resin can be formed by applying a known method.
• the method is, for example, a one-shot method in which each component is reacted at once, or a multi-step method in which each component is reacted in stages.
• a urethane resin having a carboxyl group is preferably formed by a multi-step method because the introduction of the carboxyl group is easy.
• the catalyst used for forming the urethane resin is not particularly limited.
• the polyamine may contain primary amino groups, secondary amino groups, and tertiary amino groups. Such polyamines also exhibit the effect of improving the adhesion between the resin film and the easy-adhesion layer.
• the polyamine may contain polyalkyleneimine.
• Polyalkyleneimine is suitable as an alkali component of the easy-adhesion layer.
• the polyalkyleneimine may be linear or have a branched structure.
• Polyalkyleneimines are preferably used as polyamines.
• polyalkyleneimines include polyalkyleneimine obtained by polymerizing one or more of alkyleneimine having 2 to 6 carbon atoms, derivatives obtained by adding unsaturated carboxylic acid or alkylene oxide to polyalkyleneimine, and the like. mentioned.
• alkyleneimine having 2 to 6 carbon atoms include ethyleneimine, propyleneimine, 1,2-butyleneimine, 2,3-butyleneimine, 1,1-dimethylethyleneimine and the like.
• polyethyleneimine, polypropyleneimine, polyethyleneimine derivatives, and polypropyleneimine derivatives are preferable, and polyethyleneimine and polyethyleneimine derivatives are more preferable.
• polyethyleneimine and polyethyleneimine derivatives include the already commercially available Epomin series manufactured by Nippon Shokubai Co., Ltd.; 103, Epomin SP-110, Epomin SP-200, Epomin SP-300, Epomin SP-1000, and Epomin SP-1020 (all of which are trade names).
• the polyalkyleneimine contains a primary amino group, a secondary amino group, and a tertiary amino group, and may have a branched structure.
• a polyalkyleneimine having such a structure is suitable as an alkali component of the easy-adhesion layer.
• the adhesion between the resin film and the easy-adhesion layer can be improved.
• the polyamine content in the easy-adhesion layer may be 0.0098% by weight to 1.4098% by weight.
• the presence and content of polyamine in the easy-adhesion layer can be examined, for example, by known analysis methods such as NMR.
• the fine particles may be either inorganic fine particles or organic fine particles.
• Inorganic fine particles include, for example, inorganic oxides such as silica, titania, alumina, and zirconia; fine particles such as calcium carbonate, talc, clay, calcined kaolin, calcined calcium silicate, hydrated calcium silicate, aluminum silicate, magnesium silicate, and calcium phosphate.
• the organic fine particles are, for example, fine particles of silicone-based resin, fluorine-based resin, or acrylic-based resin. Among them, silica fine particles are preferable. Silica fine particles improve blocking resistance. In addition, since silica fine particles are excellent in transparency, coloring of the optical film and an increase in haze ratio hardly occur.
• the particle size (average particle size) of the fine particles is preferably 10 to 1000 nm.
• the average particle diameter of the fine particles is preferably smaller than the wavelength of visible light from the viewpoint of suppressing light scattering by the particles, and is preferably as small as possible, but is preferably larger from the viewpoint of blocking properties.
• the upper limit of the average particle size is, for example, 900 nm or less, 800 nm or less, 700 nm or less, or 600 nm or less, more preferably 500 nm or less, more preferably 400 nm or less, and still more preferably 350 nm or less.
• the lower limit is 20 nm or more, 40 nm or more, 60 nm or more, 80 nm or more, 100 nm or more, more preferably 120 nm or more, 140 nm or more, 160 nm or more, 180 nm or more, 200 nm or more in this order, 220 nm or more, 240 nm or more, 260 nm or more, 280 nm Above, 300 nm or more, 320 nm or more, and 340 nm or more are more preferable in that order.
• the particle size distribution of fine particles is preferably 1.0 to 1.2.
• the content of fine particles in the easy-adhesion layer is not particularly limited, but the upper limit of the content per 100 parts by weight of the binder resin (solid content: solid content including cross-linking agent when cross-linking agent is included) is 30. Less than 20 parts by weight is preferred, and less than 5 parts by weight is even more preferred. When the content of fine particles is less than 30 parts by weight, the strength of the easy-adhesion layer is excellent.
• the lower limit of the content is preferably 0.1 parts by weight or more, more preferably 0.2 parts by weight or more, and even more preferably 0.5 parts by weight or more. When the fine particle content is 0.1 parts by weight or more, the optical film has excellent blocking resistance.
• the content of fine particles should be large in order to obtain the effect of improving blocking resistance. It is preferably 1.0 parts by weight or more, 5.0 parts by weight or more, and 10.0 parts by weight or more. In addition, if the average particle size is large (for example, 200 nm or more), the content of fine particles should be small from the viewpoint of suppressing light scattering, and the upper limit of the content is less than 2.0 parts by weight and 1.0 parts by weight. Less than 1 part is more preferable.
• the thickness of the easy-adhesion layer is not limited and varies depending on the thickness of the film, but is preferably 100 nm to 10 ⁇ m, more preferably 100 nm to 5 ⁇ m, even more preferably 200 nm to 1.5 ⁇ m. Within this range, the adhesion of the optical film to other members by the easy-adhesion layer is good. In addition, it is possible to suppress the occurrence of retardation in the easy-adhesion layer itself.
• the ratio r/d between the thickness d of the easy-adhesion layer and the average particle diameter r of the fine particles contained in the easy-adhesion layer is preferably 0.3 to 1.4, more preferably 0.4 to 1.1. 0.6 to 1.0 is more preferable. Within this range, both blocking resistance and transparency in the optical film of the present embodiment are further ensured.
• the method of forming the easy-adhesion layer on the surface of the optical film is not limited, and a known method may be used.
• the easy-adhesion layer is preferably formed by applying an easy-adhesion composition containing a binder resin, a polyamine, and fine particles to the surface of the resin film to form a coating film of the easy-adhesion composition, and drying the coating film.
• the easy-adhesion composition is preferably a water-based composition. Compared to organic solvent-based compositions, water-based compositions cause less burden on the environment when forming an easy-adhesion layer, and are superior in workability.
• the water-based composition is, for example, a binder resin dispersion. Dispersions are typically emulsions of binder resins. The binder resin emulsion becomes a resin layer by drying. Fine particles contained in the emulsion remain as they are in the resin layer.
• the fine particles are preferably blended as an aqueous dispersion such as colloidal silica.
• the colloidal silica may be commercially available as long as the ranges stated above for the average particle size and particle size distribution are met.
• the easy-adhesion composition is a water-based composition containing a urethane resin
• an organic solvent that is inert to polyisocyanate and compatible with water when forming the urethane resin.
• organic solvents include ester solvents such as ethyl acetate, butyl acetate and ethyl cellosolve acetate; ketone solvents such as acetone, methyl ethyl ketone and methyl isobutyl ketone; and ether solvents such as dioxane, tetrahydrofuran and propylene glycol monomethyl ether.
• the performance of the easy-adhesion layer is improved by further containing a cross-linking agent.
• a cross-linking agent is not particularly limited.
• the urethane resin has a carboxyl group
• the cross-linking agent is preferably a polymer having a group capable of reacting with the carboxyl group.
• the group capable of reacting with a carboxyl group is, for example, an organic amino group, an oxazoline group, an epoxy group, or a carbodiimide group, preferably an oxazoline group.
• a cross-linking agent having an oxazoline group has a long pot life at room temperature when mixed with a urethane resin, and the cross-linking reaction proceeds with heating, resulting in good workability.
• the polymer is, for example, a (meth)acrylic polymer or a styrene-acrylic polymer, preferably a (meth)acrylic polymer.
• the cross-linking agent is a (meth)acrylic polymer
• the performance of the easy-adhesion layer is further improved.
• the (meth)acrylic polymer is stably compatible with the water-based easy-adhesion composition and crosslinks the urethane resin well.
• the content of the urethane resin is preferably 1.5 to 15% by weight, more preferably 2 to 10% by weight. When the content is within these ranges, the easy-adhesion composition has high coatability when applied to the surface of an optical film, particularly an acrylic resin film.
• the content of the cross-linking agent is preferably 1 to 30 parts by weight, more preferably 3 to 20 parts by weight, per 100 parts by weight of the urethane resin (solid content).
• the easy-adhesion composition contains a urethane resin
• it preferably contains a neutralizer.
• Neutralizing agents are, for example, ammonia, N-methylmorpholine, triethylamine, dimethylethanolamine, methyldiethanolamine, triethanolamine, morpholine, tripropylamine, ethanolamine, triisopropanolamine, 2-amino-2-methyl-1- is propanol.
• the easy-adhesion composition may contain additives.
• Additives are, for example, dispersion stabilizers, thixotropic agents, antioxidants, UV absorbers, defoamers, thickeners, dispersants, surfactants, catalysts and antistatic agents.
• the optical film of this embodiment is excellent in adhesiveness to other members and blocking resistance. It also has excellent transparency and usually has a haze ratio of 1.5% or less. Depending on the structure of the optical film of this embodiment, the haze ratio is 1.0% or less, further 0.5% or less.
• the optical films of the present embodiment are, for example, polarizer protective films, retardation films, viewing angle compensation films, light diffusion films, reflective films, antireflection films, antiglare films, brightness enhancement films, and conductive films for touch panels.
• the retardation exhibited by the optical film of this embodiment can be controlled by the film composition and stretched state.
• the optical film of the present embodiment may be an optically isotropic film, or may be an optically anisotropic film (for example, exhibiting birefringence such as retardation).
• the optical film of the present embodiment is used as a retardation film, it is suitable for use in image display devices such as LCDs.
• the retardation film can be used, for example, for LCD color tone compensation and viewing angle compensation.
• the retardation film Since the retardation film has an easy-adhesion layer, it can be used in forms other than those normally used as retardation films. Specifically, for example, it may be used by bonding to a polarizer included in an LCD. In this case, the retardation film functions as a normal retardation film for color tone compensation or viewing angle compensation and as a polarizer protective film for protecting the polarizer. This form can omit the polarizer protective film having no retardation, which has conventionally been used separately from the retardation film, and is therefore advantageous for making the LCD thinner and more functional.
• Functional coating layers include, for example, an antistatic layer, an adhesive layer, an adhesive layer, an easy adhesive layer, an antiglare (non-glare) layer, an antifouling layer such as a photocatalyst layer, an antireflection layer, a hard coat layer, and an ultraviolet shielding layer. layer, heat ray shielding layer, electromagnetic wave shielding layer, gas barrier layer, and the like.
• optical member The optical film of this embodiment is suitable for optical members such as, for example, polarizing plates, diffusion plates, light guides, and prism sheets.
• a polarizing plate will be described as an example of the optical member of this embodiment.
• a pair of polarizing plates are arranged in the LCD so as to sandwich the liquid crystal cell based on the image display principle.
• the polarizing plate has, for example, a structure in which the optical film (polarizer protective film) of the present embodiment is laminated on at least one surface of a polarizer via an easy-adhesion layer.
• a triacetyl cellulose (TAC) film is used as a polarizer protective film.
• TAC film does not have sufficient moisture and heat resistance, and when the TAC film is used as a polarizer protective film, the properties of the polarizing plate may deteriorate in a high-temperature or high-humidity environment.
• the TAC film has a retardation in the thickness direction, and this retardation adversely affects the viewing angle characteristics of an image display device such as an LCD, especially a large-screen image display device.
• an acrylic resin film for the polarizer protective film because it can improve the moisture-heat resistance and the optical properties as compared with the TAC film.
• a polarizing plate is typically manufactured by laminating an optical film and a polarizer via an adhesive layer.
• the optical film has an easy-adhesion layer, both are laminated so that the easy-adhesion layer is on the polarizer side.
• an adhesive composition that becomes an adhesive layer after drying is applied to the surface of either the polarizer or the optical film, and then the two are bonded together and dried.
• Examples of the method of applying the adhesive composition include roll method, spray method, and dipping method.
• the adhesive composition contains a metal compound colloid
• the adhesive composition is applied so that the thickness of the adhesive layer after drying is larger than the average particle size of the metal compound colloid particles.
• the drying temperature is typically 5-150°C, preferably 30-120°C.
• the drying time is typically 120 seconds or longer, preferably 300 seconds or longer.
• the polarizer is not limited, and any suitable polarizer can be adopted according to the functions required as a polarizing plate.
• the polarizer is formed by adding iodine or dichroic to a hydrophilic polymer film such as a polyvinyl alcohol (PVA) film, a partially formalized PVA film, or a partially saponified ethylene-vinyl acetate copolymer (EVA) film.
• PVA polyvinyl alcohol
• EVA partially saponified ethylene-vinyl acetate copolymer
• a film uniaxially stretched by adsorbing a dichroic substance such as a sexual dye and a polyene-based oriented film using dehydrated PVA or dehydrochlorinated polyvinyl chloride.
• a film obtained by adsorbing a dichroic substance to a PVA-based film and uniaxially stretching the film is preferable as the polarizer.
• This polarizer exhibits a high polarization dichroism ratio.
• the thickness of the polarizer is not limited and is generally about 1 to 80 ⁇ m.
• a polarizer obtained by adsorbing iodine to a PVA-based film and uniaxially stretching can be produced, for example, by immersing a PVA-based film in an aqueous solution containing iodine to dye it and then uniaxially stretching it at a draw ratio of 3 to 7 times.
• the aqueous solution used for dyeing may contain boric acid, zinc sulfate, zinc chloride, etc., if necessary.
• an aqueous solution of iodide such as potassium iodide may be used.
• the PVA-based film may be immersed in water and washed with water before dyeing. By washing the PVA-based film with water, stains, antiblocking agents, and the like present on the surface of the film can be removed. Furthermore, since the PVA-based film is swollen by washing with water, unevenness during dyeing is suppressed. Stretching may be performed before dyeing, after dyeing, or simultaneously with dyeing.
• the adhesive composition that becomes the adhesive layer after drying is not limited.
• the bonding method is not limited, and water glue or UV bonding may be used.
• the adhesive composition preferably contains a PVA-based resin.
• PVA-based resins include, for example, the following polymers: saponified products of polyvinyl acetate and derivatives thereof; saponified products of copolymers of vinyl acetate and other monomers; Modified PVA that has been made, grafted or phosphorylated.
• the above other monomers include, for example, (anhydride) maleic acid, fumaric acid, crotonic acid, itaconic acid, (meth) acrylic acid and other unsaturated carboxylic acids and their esters; ethylene, propylene and other ⁇ -olefins; meth)allylsulfonic acid (soda), sodium sulfonate (monoalkylmalate), sodium disulfonate alkylmalate, N-methylolacrylamide, acrylamide alkylsulfonic acid alkali salt, N-vinylpyrrolidone, N-vinylpyrrolidone derivative .
• the PVA-based resin preferably contains acetoacetyl group-containing PVA. In this case, the adhesion between the polarizer and the optical film (especially the acrylic resin film) is improved, and the durability of the polarizing plate is improved.
• the average degree of polymerization of the PVA-based resin is preferably about 100 to 5000, more preferably 1000 to 4000, from the viewpoint of adhesiveness of the adhesive composition.
• the average degree of saponification of the PVA-based resin is preferably about 85 to 100 mol %, more preferably 90 to 100 mol %, from the viewpoint of adhesiveness of the adhesive composition.
• Acetoacetyl group-containing PVA can be obtained, for example, by reacting PVA and diketene by any method.
• Specific examples include a method of adding diketene to a dispersion obtained by dispersing PVA in a solvent such as acetic acid; a method of adding diketene to a solution of PVA dissolved in a solvent such as dimethylformamide or dioxane; a method of adding diketene gas to PVA.
• it is a method of directly contacting the liquid diketene.
• the degree of acetoacetyl group modification in the acetoacetyl group-containing PVA is typically 0.1 mol% or more, preferably 0.1 to 40 mol%, more preferably 1 to 20%, still more preferably 2 to 7 mol %.
• a sufficient effect of modification for example, improvement in water resistance
• the degree of acetoacetyl group modification of PVA can be measured by NMR.
• the adhesive composition may contain a cross-linking agent.
• the cross-linking agent is not limited, it is a compound having at least two functional groups exhibiting reactivity with the PVA-based resin.
• Cross-linking agents include, for example, alkylene diamines having an alkylene group and two amino groups, such as ethylene diamine, triethylene diamine, hexamethylene diamine; tolylene diisocyanate, hydrogenated tolylene diisocyanate, trimethylolpropane tolylene diisocyanate adduct, triphenylmethane Isocyanates such as triisocyanate, methylenebis(4-phenylmethanetriisocyanate), isophorone diisocyanate, and ketoxime-blocked or phenol-blocked products thereof; ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerin diglycidyl ether, glycerin Epoxies such as trig
• amino-formaldehyde resins and dialdehydes are preferred as cross-linking agents.
• the amino-formaldehyde resin preferably has methylol groups, preferably methylolmelamine.
• a preferred dialdehyde is glyoxal.
• the blending amount of the cross-linking agent in the adhesive composition can be appropriately set according to the type of PVA-based resin. Typically, it is about 10 to 60 parts by weight, preferably 20 to 50 parts by weight, per 100 parts by weight of the PVA-based resin. Within this range, good adhesion is obtained. Gelation of the adhesive composition can be suppressed by appropriately adjusting the blending amount of the cross-linking agent. In this case, the usable time (pot life) of the adhesive composition is extended, and industrial use is facilitated.
• the adhesive composition may contain a metal compound colloid.
• a metal compound colloid may be a colloid in which particles of a metal compound are dispersed in a dispersion medium.
• Metal compound colloids can be permanently stable colloids due to electrostatic stabilization due to mutual repulsion of like charges on the particles. By including the metal compound colloid in the adhesive composition, the stability of the adhesive composition is improved even when the amount of the cross-linking agent is large.
• the average particle size of the colloidal particles in the metal compound colloid can be set within a range that does not adversely affect the optical properties (eg, polarization properties) of the polarizing plate.
• the colloidal particles preferably have an average particle size of 1 to 100 nm, more preferably 1 to 50 nm. Within these ranges, the colloidal particles can be uniformly dispersed in the adhesive layer. As a result, the adhesion is ensured and the occurrence of knicks is suppressed. When a knick defect occurs, for example, light leakage occurs in an image display device incorporating the polarizing plate.
• Metal compounds are not limited, for example, oxides such as alumina, silica, zirconia, titania; metal salts such as aluminum silicate, calcium carbonate, magnesium silicate, zinc carbonate, barium carbonate, calcium phosphate; celite, talc, clay, minerals such as kaolin. Metal compound colloids with a positive charge are preferred. Alumina and titania are preferable, and alumina is particularly preferable as the metal compound that becomes a positively charged colloid.
• a metal compound colloid is typically a colloidal solution dispersed in a dispersion medium.
• the dispersion medium is, for example, water or alcohol.
• the solid content concentration in the colloidal solution is typically about 1 to 50% by weight, preferably 1 to 30% by weight.
• the colloidal solution may contain acids such as nitric acid, hydrochloric acid and acetic acid as stabilizers.
• the amount of the metal compound colloid (in terms of solid content) in the adhesive composition is preferably 200 parts by weight or less, more preferably 10 to 200 parts by weight, and further 20 to 175 parts by weight based on 100 parts by weight of the PVA-based resin. 30 to 150 parts by weight are particularly preferred. Within these ranges, the adhesion of the adhesive composition is more reliable, and the occurrence of knicks is more suppressed.
• the adhesive composition contains coupling agents such as silane coupling agents and titanium coupling agents; various tackifiers; ultraviolet absorbers; antioxidants; You can stay.
• the adhesive composition is preferably an aqueous solution (resin solution).
• concentration of the resin in the aqueous solution is preferably 0.1 to 15% by weight, more preferably 0.5 to 10% by weight, from the viewpoint of the composition's coatability and storage stability.
• the viscosity of the aqueous solution is preferably 1 to 50 mPa ⁇ s. When the adhesive composition contains a metal compound colloid, the occurrence of knicks is effectively suppressed even with a low viscosity of 1 to 20 mPa ⁇ s.
• the pH of the aqueous solution is preferably 2 to 6, more preferably 2.5 to 5, still more preferably 3 to 5, and particularly preferably 3.5 to 4.5.
• adjusting the pH of the aqueous solution adjusts the surface charge of the metal compound colloid.
• the surface charge is preferably positive. Being positively charged further suppresses the occurrence of knick defects.
• the surface charge of the metal compound colloid can be confirmed, for example, by measuring the zeta potential with a zeta potential measuring instrument.
• the adhesive composition which is an aqueous solution (resin solution)
• aqueous solution resin solution
• the adhesive composition can be formed by a known method.
• the adhesive composition contains a cross-linking agent and a metal compound colloid
• a method of mixing the PVA-based resin and the cross-linking agent to adjust the concentration to an appropriate solution and adding the metal compound colloid can be employed.
• the cross-linking agent may be mixed while considering when the adhesive composition will be used.
• the concentration of the aqueous solution can be adjusted after the aqueous solution is prepared.
• the thickness of the adhesive layer formed from the adhesive composition can be appropriately set according to the composition of the composition.
• the thickness is preferably 10 to 300 nm, more preferably 10 to 200 nm, particularly preferably 20 to 150 nm. Within this range, the adhesive layer exhibits sufficient adhesive strength.
• the optical film of the present embodiment is suitable for image display devices such as electroluminescence (EL) display panels, plasma display panels (PDP), field emission displays (FEDs), and LCDs.
• EL electroluminescence
• PDP plasma display panels
• FEDs field emission displays
• LCDs liquid crystal display devices
• the configuration of the image display device provided with the optical film of the present embodiment is not particularly limited, and members such as a power source, a backlight section, and an operation section may be appropriately provided as necessary.
• a method for producing an optical film includes a step of applying an easy-adhesive composition containing a binder resin, a polyamine, and fine particles to the surface of a resin film to form a coating film of the easy-adhesive composition (coating step); and a step of drying the applied film to form an easy-adhesion layer on the surface of the resin film (drying step).
• coating step a step of applying an easy-adhesive composition containing a binder resin, a polyamine, and fine particles to the surface of a resin film to form a coating film of the easy-adhesive composition
• drying step drying the applied film to form an easy-adhesion layer on the surface of the resin film
• a coating film of the easy-adhesive composition is formed on at least one surface of the resin film.
• the coating film is formed on one surface of the optical film.
• a known method can be applied to the method of applying the easy-adhesion composition in the application step.
• the methods are, for example, bar coating, roll coating, gravure coating, rod coating, slot orifice coating, curtain coating, and fountain coating.
• the thickness of the coating film formed in the coating step can be appropriately adjusted according to the thickness required when the coating film serves as an easy-adhesion layer.
• the surface of the resin film to which the easy-adhesion composition is applied is preferably surface-treated.
• Surface treatments are as described above, with corona discharge treatment and plasma treatment being preferred.
• Conditions for the corona discharge treatment are not limited.
• the amount of electron irradiation in corona discharge treatment is preferably 50 to 150 W/m 2 /min, more preferably 70 to 100 W/m 2 /min.
• the drying temperature is typically 50° C. or higher, preferably 90° C. or higher, more preferably 110° C. or higher. By setting the drying temperature within these ranges, for example, an optical film having excellent corrosion resistance (especially in a high-temperature, high-humidity environment) can be obtained.
• the upper limit of the drying temperature is preferably 200°C or lower, more preferably 180°C or lower.
• the resin film may be stretched between the coating process and the drying process, simultaneously with the drying process, or after the drying process.
• a known method can be employed for stretching the resin film after the easy-adhesion composition has been applied. It can be axially stretched.
• the resin film that forms the coating film of the easy-adhesive composition in the coating step may be an unstretched resin film or a stretched resin film.
• the resin film before the coating step is an unstretched film and the optical film to be finally produced is a biaxially stretched film
• biaxial stretching may be performed after the coating step.
• the direction of uniaxial stretching may be the MD direction, and the film may be stretched in the TD direction after the coating step. .
• a known stretching machine can be used for stretching the resin film.
• the longitudinal stretching machine is not particularly limited, but an oven stretching machine is preferred.
• An oven longitudinal stretching machine is generally composed of an oven and transport rolls respectively provided on the inlet side and the outlet side of the oven.
• the resin film is stretched in the conveying direction by providing a peripheral speed difference between the conveying roll on the entrance side of the oven and the conveying roll on the exit side of the oven.
• a transverse stretching machine is not particularly limited, but a tenter stretching machine is preferable.
• the tenter stretching machine may be either a grip type or a pin type, but the grip type is preferable because tearing of the resin film is less likely to occur.
• a grip-type tenter stretching machine is generally composed of a transverse stretching clip running device and an oven.
• the resin film is conveyed in a state in which the lateral end portion of the resin film is sandwiched by clips. At this time, the resin film is laterally stretched by opening the guide rails of the clip traveling device and widening the distance between the two rows of clips on the left and right sides.
• a grip-type tenter stretching machine simultaneous biaxial stretching is possible by providing the clip with an expansion/contraction function in the transport direction of the resin film.
• it may be an oblique stretching machine that stretches the film in the direction of transport of the film at different speeds on the left and right sides of the film in the stretching direction.
• the stretching temperature is preferably near the Tg of the resin constituting the resin film. Specifically, the range of Tg-30°C to Tg+100°C is preferable, and the range of Tg-20°C to Tg+80°C is more preferable. A sufficient draw ratio can be stably achieved by appropriately adjusting the drawing temperature.
• the draw ratio defined by the area ratio is preferably 1.1 to 25 times, more preferably 1.3 to 10 times.
• the drawing speed is preferably 10 to 20000%/min, more preferably 100 to 10000%/min for drawing in one direction.
• the resin film having the easy-adhesion composition coating film formed thereon may be stretched in a heated atmosphere.
• the heat applied to the resin film for stretching dries the coating film of the easy-adhesion composition formed on the surface of the resin film to form an easy-adhesion layer.
• the stretching temperature described above is a sufficiently high temperature for forming an easy-adhesion layer from the coating film of the easy-adhesion composition.
• the process from forming the resin film to obtaining the optical film, which is a stretched film can be performed continuously.
• Such a step of continuously applying the adhesive composition is called in-line coating.
• surface treatment such as corona discharge treatment and plasma treatment
• the manufacturing method of this embodiment may include arbitrary steps other than the steps described above.
• the step is, for example, a step of laminating an additional layer (for example, a resin layer) on the formed optical film, or a step of subjecting the formed optical film to post-processing such as coating treatment or surface treatment.
• Tg Glass transition temperature
• the glass transition temperature was determined according to the Japanese Industrial Standard JIS K7121. Specifically, using a differential scanning calorimeter (Thermo plus EVO DSC-8230 manufactured by Rigaku Co., Ltd.), a sample of about 10 mg was heated from room temperature to 200 ° C. in a nitrogen gas atmosphere (heating rate 20 ° C./min). Evaluation was made by the starting point method from the DSC curve obtained. ⁇ -alumina was used as a reference.
• Total light transmittance, haze The total light transmittance, haze (total haze), and internal haze of the produced optical film were determined based on the provisions of JIS K7136 using a turbidity meter (manufactured by Nippon Denshoku Industries, NDH5000 ) was used. The internal haze was measured in a state in which the film to be measured was immersed in tetralin in a quartz cell.
• (1-6) Adhesion Between Resin Film and Easy-Adhesion Layer Adhesion between the prepared resin film and the easy-adhesion layer was evaluated by performing a substrate texture test in accordance with JIS K5400 3.5 and evaluated in the following manner. 1 mm square substrate mesh-like incisions were made with a sharp knife at three locations on the easy-adhesion layer surface of the test sample. Cellophane tape (24 mm width, JIS Z1522) was adhered to the cut with a wooden spatula. After that, the cellophane tape was peeled off, and the presence or absence of peeling of the easily adhesive layer was confirmed.
• Blocking Resistance of Optical Film Blocking resistance of the produced optical film was evaluated as follows. After winding the produced optical film on a roll to form a film roll, this was allowed to stand for 24 hours. After the standing, the film roll was visually checked, and while the optical film was unwound from the film roll, the surface was visually checked over the entire longitudinal direction of the optical film to evaluate the blocking resistance. Evaluation criteria are as follows. ⁇ : No deformation of the film roll and wrinkles of the optical film that was fed out were observed. x: Deformation of the film roll or wrinkles of the unwound optical film were confirmed.
• A When coating unevenness, streaks, and thickness unevenness could not be visually confirmed, and a uniform coating film was obtained.
• B When at least one of coating unevenness, streaks, and thickness unevenness can be visually confirmed, and a uniform coating film cannot be obtained.
• a mixed solution of an antioxidant/cyclization catalyst deactivator prepared separately was charged at a rate of 0.68 kg/h, and after the first vent, 0.22 kg/h of ion-exchanged water was charged. After the 2nd and 3rd vents at speed, respectively.
• the mixed solution of antioxidant/cyclization catalyst deactivator contains 50 parts by weight of antioxidant (Ciba Specialty Chemicals, Irganox 1010) and 35 parts by weight of zinc octylate (Nihon Kagaku Sangyo Co., Ltd.) as a deactivator. Nikka Octix zinc (3.6% by weight) was dissolved in 200 parts by weight of toluene.
• pellets of styrene-acrylonitrile copolymer (AS resin: ratio of styrene unit/acrylonitrile unit is 73% by weight/27% by weight, weight average molecular weight is 220,000) were fed from the side feeder. , at a rate of 15 kg/h.
• the hot-melt resin remaining in the extruder is discharged from the tip of the extruder while being filtered through a polymer filter, pelletized by a pelletizer, and having a lactone ring structure in the main chain (meth).
• Transparent acrylic resin pellets (1A) containing an acrylic polymer as a main component (content of 75% by weight) and a styrene-acrylonitrile copolymer of 25% by weight were obtained.
• the acrylic resin constituting the pellet (1A) had a Tg of 122°C and a weight average molecular weight of 151,000.
• the prepared acrylic resin film is freely stretched in the MD direction (machine direction, extrusion direction) using a biaxial stretching machine (Toyo Seiki Seisakusho, TYPE EX4) at a stretching ratio of 2.0 times and a stretching temperature of 140 ° C.
• the film was uniaxially stretched to obtain a stretched acrylic resin film (F1).
• the temperature inside the tank is raised while maintaining the nitrogen atmosphere, and when the temperature inside the tank reaches 100° C., 0.075 parts by weight of t-butylperoxyisopropyl carbonate is added. Nitrogen bubbling was started in the bath. Next, a mixed solution of 2 parts by weight of styrene and 0.075 parts by weight of t-butylperoxyisopropyl carbonate was added to the tank at a constant rate over 5 hours, while the polymerization temperature was 105 to 110° C. under reflux. The polymerization reaction was allowed to proceed for 15 hours.
• the resin in a hot melt state in the extruder is extruded from the tip of the extruder and pelletized by a pelletizer to obtain a transparent acrylic resin composed of a (meth)acrylic polymer having an N-substituted maleimide structure in the main chain.
• a pellet (2A) was obtained.
• the acrylic resin constituting the pellet (2A) had a Tg of 138°C and a weight average molecular weight of 200,000.
• the prepared acrylic resin film is freely stretched in the MD direction (flow direction, extrusion direction) using a biaxial stretching machine (Toyo Seiki Seisakusho, TYPE EX4) at a stretching ratio of 2.0 times and a stretching temperature of 155 ° C.
• the film was uniaxially stretched to obtain a stretched acrylic resin film (F2).
• the prepared acrylic resin film is freely stretched in the MD direction (machine direction, extrusion direction) using a biaxial stretching machine (Toyo Seiki Seisakusho, TYPE EX4) at a stretching ratio of 2.0 times and a stretching temperature of 140 ° C.
• the ends were uniaxially stretched to obtain a stretched acrylic resin film (F3).
• the polymerization reaction was allowed to proceed while continuously dripping the polymerization initiator solution of 1 part by weight into the container over 2 hours. After the dropwise addition was completed, the temperature in the container was raised to 80° C., and the polymerization reaction was allowed to continue for an additional 2 hours. Next, after the temperature in the container was lowered to 40° C., the content was passed through a 300-mesh wire mesh to obtain an emulsion polymerization liquid of elastic organic fine particles.
• the obtained emulsion polymerization solution of the elastic organic fine particles was salted out with calcium chloride and solidified. A layer refractive index of 1.516) was obtained.
• the prepared acrylic resin film is freely stretched in the MD direction (machine direction, extrusion direction) using a biaxial stretching machine (Toyo Seiki Seisakusho, TYPE EX4) at a stretching ratio of 2.0 times and a stretching temperature of 140 ° C.
• the film was uniaxially stretched to obtain a stretched acrylic resin film (F6).
• stearyl phosphate (“Phoslex A-18” manufactured by Sakai Chemical Industry Co., Ltd.) is added to the obtained polymerization solution as a catalyst for the cyclization condensation reaction (cyclization catalyst), and the The cyclization condensation reaction for forming the lactone ring structure was allowed to proceed under reflux at 110° C. for 2 hours.
• the resulting polymerization solution is passed through a shell and tube heat exchanger heated to 240° C.
• the resin composition in a hot melt state remaining in the extruder is discharged from the tip of the extruder while being filtered through the polymer filter, passed through the provided die, and filtered through a filter with a pore size of 1 ⁇ m ( Organo Co., Ltd. "Product name: Micropore Filter 1EU”), the strand is cooled in a water tank filled with cooling water maintained at a temperature within the range of 30 ⁇ 10 ° C., and then introduced into a cutting machine (pelletizer).
• pellets made of the resin composition (7A) containing a lactone ring-based polymer having a lactone ring structure in the main chain were obtained.
• the obtained resin composition (7A) had a weight average molecular weight of 132,000, a number average molecular weight of 59,000, a glass transition temperature of 121°C, a thermal decomposition initiation temperature of 335°C, and a refractive index of 1.501. there were.
• the produced pellet (7A) was formed into a film in the same manner as in Production Example 1 to obtain a stretched acrylic resin film (F7).
• ⁇ SF210 Daiichi Kogyo Seiyaku Co., Ltd., Superflex 210, solid content 35% by weight ⁇ W-5030: Takelac W-5030, made by Mitsui Chemicals Polyurethane, solid content 30% by weight ⁇ CP-7020: Hydran CP-7020 manufactured by DIC, solid content 40% by weight ⁇ SF620: Daiichi Kogyo Seiyaku Co., Ltd., Superflex 620, solid content 30% by weight ⁇ AP-40N: manufactured by DIC, Hydran AP-40N, solid content 35% by weight ⁇ KE-W30: Nippon Shokubai Co., Ltd., Seahoster KE-W30, average particle size (primary particle size) 0.28 ⁇ m, particle size distribution 1.1, solid content 20% by weight ⁇ KE-W10: Nippon Shokubai Co., Ltd., Seahoster KE-W10, average particle size (primary particle size) 0.11 ⁇ m, particle size distribution 1.1, solid content
• Example 1 The easily adhesive composition (1B) prepared in Production Example 11 was applied to one surface of the acrylic resin film (F1) prepared in Production Example 1 so that the thickness of the coating film after drying was 270 nm. , the whole was dried at 100° C. for 2 minutes. Thus, an optical film having an easy-adhesion layer formed on one surface was obtained. The fine particles contained in the formed easy-adhesion layer retained the shape in the easy-adhesion composition (1B).
• Examples 2 to 58 Comparative Examples 1 to 16
• Tables 2A to 2C an optical film having an easy-adhesion layer formed on one surface was obtained in the same manner as in Example 1 by changing the combination of the acrylic resin film and the easy-adhesion composition. .
• Example 59 On one surface of the acrylic resin film (F1) produced in Production Example 1, the easy-adhesive composition (1B) produced in Production Example 11 was applied so that the thickness of the coating film after drying was 600 nm. After coating with a machine, the whole was dried at 100° C. for 2 minutes. Next, the film obtained in this way is stretched using a biaxial stretching machine (TYPE EX4, manufactured by Toyo Seiki Seisakusho) in the TD direction (the direction perpendicular to the MD direction in the film plane, the width direction during extrusion molding). An acrylic resin film, which is a biaxially stretched film, is uniaxially stretched at the free end at a stretching ratio of 1.5 times and a stretching temperature of 140 ° C. to form an easy-adhesion layer containing urethane resin and fine particles on one surface. An optical film was obtained.
• a biaxial stretching machine TYPE EX4, manufactured by Toyo Seiki Seisakusho
• the easily adhesive composition (11B) prepared in Production Example 21 was applied to one surface of the acrylic resin film after longitudinal stretching by gravure coating so that the thickness of the coating film after drying was 1050 nm.
• the acrylic resin film was directly supplied to a tenter transverse stretching machine and stretched in its width direction at a stretching temperature of 132° C. and a stretching ratio of 3.0 times (transverse stretching).
• an optical film (thickness: 58 ⁇ m) composed of an acrylic resin film that is a biaxially stretched film was formed on one main surface with an easy-adhesion layer (thickness: 350 nm) containing urethane resin and fine particles. Obtained.
• Example 61-79 Comparative Examples 18-20
• Table 4 an optical film having an easy-adhesion layer formed on one surface was obtained in the same manner as in Example 57 by changing the combination of the resin pellet and the easy-adhesion composition.
• Example 81-82 Comparative Example 21
• Table 5 an optical film having an easy-adhesion layer formed on one main surface was obtained in the same manner as in Example 13 by changing the combination of the resin pellet and the easy-adhesion composition.
• the easy-adhesion layer contains a binder resin, polyamine, and fine particles, and the content of polyamine in the easy-adhesion layer is 0.0090% by weight to 1.4100% by weight.
• the adhesiveness between the film and the easy-adhesion layer was excellent, and a uniform easy-adhesion layer could be formed.
• the use of polymeric polyamine further improves the adhesion between the resin film and the easy-adhesion layer due to the interaction between the polyamine and the base film. Furthermore, it was found that blocking resistance can be ensured by setting the content of polyamine to 0.0489% by mass or more, for example.
• the optical film of the present invention is used in image display devices such as LCDs, and is suitable for use in various protective films such as polarizer protective films, retardation films, and polarizing films.

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