Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J7/00—Chemical treatment or coating of shaped articles made of macromolecular substances
  • C08J7/04—Coating
  • C08J7/043—Improving the adhesiveness of the coatings per se, e.g. forming primers
• • 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
  • B32B27/06—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material
  • B32B27/08—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material 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
  • B32B27/26—Layered products comprising a layer of synthetic resin characterised by the use of special additives using curing agents
• • 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
  • B32B27/36—Layered products comprising a layer of synthetic resin comprising polyesters
• • 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
  • B32B27/40—Layered products comprising a layer of synthetic resin comprising polyurethanes
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J7/00—Chemical treatment or coating of shaped articles made of macromolecular substances
  • C08J7/04—Coating
  • C08J7/042—Coating with two or more layers, where at least one layer of a composition contains a polymer binder
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K5/00—Use of organic ingredients
  • C08K5/16—Nitrogen-containing compounds
  • C08K5/22—Compounds containing nitrogen bound to another nitrogen atom
  • C08K5/24—Derivatives of hydrazine
  • C08K5/26—Semicarbazides
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D171/00—Coating compositions based on polyethers obtained by reactions forming an ether link in the main chain; Coating compositions based on derivatives of such polymers
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D175/00—Coating compositions based on polyureas or polyurethanes; Coating compositions based on derivatives of such polymers
  • C09D175/04—Polyurethanes
  • C09D175/06—Polyurethanes from polyesters
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D5/00—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D7/00—Features of coating compositions, not provided for in group C09D5/00; Processes for incorporating ingredients in coating compositions
  • C09D7/40—Additives
  • C09D7/60—Additives non-macromolecular
  • C09D7/63—Additives non-macromolecular organic
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D7/00—Features of coating compositions, not provided for in group C09D5/00; Processes for incorporating ingredients in coating compositions
  • C09D7/40—Additives
  • C09D7/65—Additives macromolecular
• • 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 easily adhesive polyester film that has excellent adhesion to various functional layers, and a laminated polyester film having such functional layers.
• Hard coat films with a transparent hard coat layer laminated on them are used on the front of displays such as touch panels, computers, televisions, and liquid crystal display devices, as well as decorative materials.
• Panel components used in displays are formed by laminating a hard coat film with a polarizer or with other components, and the lamination is performed by applying an adhesive component.
• a transparent polyester film is generally used as the transparent plastic film substrate, and in order to improve adhesion between the polyester film substrate and the hard coat layer and adhesive, a coating layer with good adhesion is often provided on the surface of the polyester film as an intermediate layer between them.
• the hard coat film is required to have durability against temperature, humidity, light, etc., transparency, chemical resistance, scratch resistance, stain resistance, etc. Also, since it is often used on the surfaces of displays and decorative materials, visibility and design are required. Therefore, in order to suppress glare and iridescent colors caused by reflected light when viewed from any angle, it is common to provide an anti-reflection layer with a multilayer structure in which a high refractive index layer and a low refractive index layer are laminated on top of the hard coat layer.
• Polarizing plates are placed on both sides of the glass substrate that forms the surface of the liquid crystal panel.
• Polarizing plates generally consist of a polarizer made of a polyvinyl alcohol film and a dichroic material such as iodine, with a polarizer protective film attached to both sides via a hydrophilic adhesive such as a polyvinyl alcohol resin.
• a polarizer protective film attached to both sides via a hydrophilic adhesive such as a polyvinyl alcohol resin.
• triacetyl cellulose film has been used as the protective film to protect the polarizer because of its optical properties and transparency.
• triacetyl cellulose does not have sufficient durability, and when a polarizing plate using triacetyl cellulose film as a polarizer protective film is used under high temperature or high humidity conditions, the performance of the polarizing plate, such as the polarization degree and hue, may deteriorate. Furthermore, in recent years, there has been a demand for thinner polarizing plates to accommodate thinner displays, but from the perspective of maintaining moisture barrier properties, there is a limit to how thin a triacetyl cellulose film can be made. Therefore, it has been proposed to use a polyester film as a polarizer protective film that has durability and moisture barrier properties (see, for example, Patent Document 1).
• the triacetyl cellulose film used as a polarizer protective film has its surface subjected to an alkali treatment, etc., and has an extremely high affinity with hydrophilic adhesives. Therefore, a protective film made of triacetyl cellulose film has extremely high adhesion to a polarizer coated with a hydrophilic adhesive.
• polyester films have insufficient adhesion to hydrophilic adhesives, and this tendency is particularly pronounced in the case of polyester films that have been oriented by a stretching treatment.
• the present invention was made against the background of the problems with the conventional technology. That is, the object of the present invention is to provide an easily adhesive polyester film that has excellent adhesion to functional layers such as a hard coat layer and an adhesive. It is also to provide a laminated polyester film that is provided with such a functional layer.
• the present invention has the following configuration.
• An easily adhesive polyester film having a polyester film substrate and a coating layer on at least one side thereof, The coating layer is formed from a composition containing a polycarbonate polyurethane resin (A), a polyester resin (B), and a blocked isocyanate-based crosslinking agent (C),
• the polycarbonate polyurethane resin (A) has structures represented by formula (1) and formula (2) in the molecule
• the polyester resin (B) has a structure represented by formula (1) and/or formula (2) in the molecule
• the blocked isocyanate crosslinking agent (C) has a structure represented by formula (1) and/or formula (2) in the molecule, Highly adhesive polyester film.
• a method for producing the highly adhesive polyester film according to [1], includes a step of applying a coating layer forming composition (coating liquid) to at least one surface of a polyester film substrate,
• the coating layer-forming composition contains a polycarbonate polyurethane resin (A), a polyester resin (B), and a blocked isocyanate-based crosslinking agent (C),
• the polycarbonate polyurethane resin (A) has structures represented by formula (1) and formula (2) in the molecule
• the polyester resin (B) has a structure represented by formula (1) and/or formula (2) in the molecule
• the blocked isocyanate crosslinking agent (C) has a structure represented by formula (1) and/or formula (2) in the molecule, Manufacturing method.
• the highly adhesive polyester film of the present invention has excellent adhesion between the functional layer and the polyester film (especially adhesion after long-term storage, etc.), and has high adhesion reliability. It also has excellent blocking resistance and transparency. Therefore, it can be widely used in optical applications, etc.
• polyester film used as a substrate in the easily adhesive polyester film of the present invention is a film mainly composed of polyester resin.
• a film mainly composed of polyester resin means a film formed from a resin composition containing 50% by mass or more of polyester resin.
• other polymers e.g., polycarbonate resin, polyimide resin, etc.
• the polyester resin is contained in an amount of 50% by mass or more, and when copolymerized with other monomers, it means that the polyester structural unit is contained in an amount of 50 mol% or more.
• the polyester film contains 90% by mass or more of polyester resin, more preferably 95% by mass or more, and even more preferably 100% by mass.
• the polyester resin material is not particularly limited, but a copolymer formed by polycondensation of a dicarboxylic acid component and a diol component, or a blend resin thereof can be used.
• dicarboxylic acid components constituting the polyester resin include terephthalic acid, isophthalic acid, orthophthalic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, diphenylcarboxylic acid, diphenoxyethanedicarboxylic acid, diphenylsulfonecarboxylic acid, anthracenedicarboxylic acid, 1,3-cyclopentanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, hexahydroterephthalic acid, hexahydroiso
• Diol components constituting polyester resins include, for example, ethylene glycol, propylene glycol, hexamethylene glycol, neopentyl glycol, 1,2-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, decamethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexadiol, 2,2-bis(4-hydroxyphenyl)propane, and bis(4-hydroxyphenyl)sulfone.
• the dicarboxylic acid component and the diol component may each be used in one or more types.
• other polycarboxylic acid components such as trimellitic acid and other polyol components such as trimethylolpropane may be added as appropriate.
• polyester resins include polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate.
• polyethylene terephthalate is preferred from the viewpoint of the balance between physical properties and cost.
• preferred copolymerization components include diethylene glycol and copolymerization components having norbornene in the side chain.
• inert particles can be contained in the film.
• inert particles include inorganic particles such as silica, kaolinite, talc, light calcium carbonate, heavy calcium carbonate, zeolite, alumina, barium sulfate, carbon black, zinc oxide, zinc sulfate, zinc carbonate, titanium dioxide, satin white, aluminum silicate, diatomaceous earth, calcium silicate, aluminum hydroxide, hydrated halloysite, magnesium carbonate, and magnesium hydroxide.
• the average particle size of the inert particles is, for example, 200 to 5000 nm, and further 250 to 4500 nm.
• This average particle size is measured using the method described in the examples (average particle size based on number by SEM).
• the content of inactive particles in the film is as small as possible. Therefore, it is preferable to have a multi-layer structure in which particles are contained only in the surface layer of the film, or to have the film substantially free of particles and to have fine particles contained only in the coating layer laminated on at least one side of the polyester film.
• substantially no particles means, for example, in the case of inorganic particles, that the content is 50 ppm or less, preferably 10 ppm or less, and most preferably below the detection limit, when elements derived from the particles are quantitatively analyzed by fluorescent X-ray analysis. This is because even if particles are not actively added to the base film, contaminants from foreign matter, or dirt adhering to the raw resin or the lines or equipment in the film manufacturing process may peel off and unavoidably become mixed into the film.
• the polyester film when the polyester film is made into a multi-layer structure, it can be made into a two-type three-layer structure in which the inner layer does not substantially contain inactive particles, and only the outermost layer (second layer) contains inactive particles. This is preferable because it makes it possible to achieve both transparency and processability.
• the polyester film that serves as the substrate may be a single layer or a laminate of two or more layers.
• various additives can be contained in the film as necessary, so long as the effects of the present invention are achieved.
• additives include antioxidants, light resistance agents, antigelling agents, organic wetting agents, antistatic agents, ultraviolet absorbers, surfactants, etc.
• the film has a laminated structure, it is also preferable to contain additives according to the function of each layer as necessary. For example, it is also a preferred embodiment to add an ultraviolet absorber or the like to the inner layer in order to prevent photodegradation of the polarizer.
• the polyester film can be produced according to a conventional method. For example, it can be obtained by melt extruding a material containing the above-mentioned polyester resin into a film shape, and then cooling and solidifying it on a casting drum to form a film. Either a non-stretched film or a stretched film can be used as the polyester film in the present invention, but a stretched film is preferable from the standpoint of durability such as mechanical strength and chemical resistance.
• the stretching method is not particularly limited, and may be a longitudinal uniaxial stretching method, a transverse uniaxial stretching method, a longitudinal and transverse sequential biaxial stretching method, a longitudinal and transverse simultaneous biaxial stretching method, or the like.
• the stretching may be performed before laminating an easily adhesive coating layer, which will be described later, or after laminating an easily adhesive coating layer. It is also possible to perform uniaxial stretching in the longitudinal or transverse direction before laminating an easily adhesive coating layer, and then stretch in the other direction after laminating the coating layer.
• the adhesive polyester film of the present invention has an adhesive coating layer laminated on at least one side of the polyester film as the substrate.
• the coating layer can be formed from a composition containing a binder resin, a crosslinking agent, and, if necessary, additives.
• the binder resin that constitutes the coating layer is a resin with high adhesive properties, and contains a polycarbonate polyurethane resin (A) that is a urethane resin with a polycarbonate structure, and a polyester resin (B), and the crosslinking agent contains a blocked isocyanate-based crosslinking agent (C).
• A polycarbonate polyurethane resin
• B polyester resin
• C blocked isocyanate-based crosslinking agent
• Polycarbonate polyurethane resin (A) contains a cyclohexane ring structure in its molecule, and has a structure in which at least one (particularly one or two) hydrogen atoms on the cyclohexane ring are replaced with a hydrocarbon group (hereinafter, this structure may be referred to as a "cyclohexane ring structure"). In other words, it has a structure in which at least one hydrogen atom on the cyclohexane ring is bonded to a carbon atom of a hydrocarbon group (for example, an alkyl group having 1 to 3 carbon atoms, an alkylene group having 1 to 3 carbon atoms, etc.).
• a hydrocarbon group for example, an alkyl group having 1 to 3 carbon atoms, an alkylene group having 1 to 3 carbon atoms, etc.
• Polycarbonate polyurethane resin (A) further has a structure containing a methylene chain having 5 to 10 carbon atoms in its molecule (hereinafter, this structure may be referred to as a "C5-C10 methylene chain structure").
• Polycarbonate polyurethane resin (A) may be one type or a mixture of two or more types.
• the polyester resin (B) has a cyclohexane ring structure and/or a C5-C10 methylene chain structure in its molecule, taking into consideration the interaction with the polycarbonate polyurethane resin (A). In other words, the polyester resin (B) has both a cyclohexane ring structure and a C5-C10 methylene chain structure, or either one of them, in its molecule.
• the polyester resin (B) may be one type or a mixture of two or more types.
• the blocked isocyanate crosslinking agent (C) has a cyclohexane ring structure and/or a C5-C10 methylene chain structure in its molecule, taking into consideration the interaction with the polycarbonate polyurethane resin (A) and the polyester resin (B). In other words, it has both a cyclohexane ring structure and a C5-C10 methylene chain structure, or either one of them, in its molecule.
• the blocked isocyanate crosslinking agent (C) may be one type or a mixture of two or more types.
• Examples of the "cyclohexane ring structure" contained in each molecule of the polycarbonate polyurethane resin (A), the polyester resin (B), and the crosslinking agent (C) that is a blocked isocyanate-based crosslinking agent include a structure represented by formula (1). (In the formula, * indicates a binding site.)
• the structure represented by the above formula (1b) is more preferably a structure derived from cyclohexanedimethanol (particularly 1,4-cyclohexanedimethanol).
• the two * marks become the sites that bond with the oxygen atoms that make up the resin.
• an example of the "C5-C10 methylene chain structure” is a structure represented by formula (2).
• n is an integer of 5 to 10, and * indicates a binding site.
• * is a site that bonds to an atom that constitutes the binder resin or the crosslinking agent.
• the atom may be the same or different, and may be a hydrogen atom, a carbon atom, an oxygen atom, a nitrogen atom, or the like. Of the two * in each formula, at least one is preferably a carbon atom, an oxygen atom, a nitrogen atom, or the like.
• n is preferably 5 to 9, and more preferably 5 to 6.
• the "cyclohexane ring structure" and “C5-C10 methylene chain structure” contained in each of the polycarbonate polyurethane resin (A), polyester resin (B), and blocked isocyanate crosslinking agent (C) may be the same or different.
• the coating layer is compatible with the composition of the functional layer described below.
• the functional layer is obtained by UV curing through UV irradiation and has a crosslinked network structure.
• the polycarbonate polyurethane resin (A), polyester resin (B) and blocked isocyanate crosslinking agent (C) of the coating layer all have at least a cyclohexane ring structure or a C5-C10 methylene chain structure in their molecules, so that the resins interact with each other and become more compatible and entangled. It is also believed that the entangled resins become entangled with the network structure of the functional layer formed thereon, resulting in a coating layer with better adhesion than conventional coating layers. Furthermore, since the coating layer contains polyester resin (B), it is believed that the adhesion to the polyester film, which is the substrate, is also improved, resulting in a coating layer with better adhesion.
• the polycarbonate polyurethane resin (A) has, in its molecule, both a cyclohexane ring structure, i.e., a structure containing a cyclohexane ring structure in which at least one hydrogen atom on the cyclohexane ring is substituted with a hydrocarbon group, and a C5-C10 methylene chain structure, i.e., a structure containing a methylene chain having 5 or more and 10 or less carbon atoms.
• a cyclohexane ring structure i.e., a structure containing a cyclohexane ring structure in which at least one hydrogen atom on the cyclohexane ring is substituted with a hydrocarbon group
• a C5-C10 methylene chain structure i.e., a structure containing a methylene chain having 5 or more and 10 or less carbon atoms.
• the content of the cyclohexane ring structure in the polycarbonate polyurethane resin (A) is usually 5% by mass or more and 55% by mass or less, preferably 10% by mass or more and 50% by mass or less, more preferably 15% by mass or more and 45% by mass or less. If the content is 5% by mass or more, the number of units of the cyclohexane ring structure that interact with each other between the resins is sufficient, so that the strength of the resin in the coating layer is maintained and the adhesion under high temperature and high humidity is also likely to be good. If the content is 55% by mass or less, the flexibility of the resin in the coating layer is maintained and the adhesion under normal temperature and high temperature and high humidity is also likely to be good.
• the content of the cyclohexane ring structure in the polycarbonate polyurethane resin (A) is calculated as the proportion of the mass of the cyclohexane ring structure (-C6H10-CH2- ) relative to 100 g of the total mass of the polycarbonate polyurethane resin (A).
• the molecular weight and mol % of each component constituting the polycarbonate polyurethane resin (A), such as the polycarbonate diol component and the diisocyanate component "the mol % of the component having a cyclohexane ring”
• the content of C5-C10 methylene chain structures in polycarbonate polyurethane resin (A) is usually 5% by mass or more and 55% by mass or less, preferably 10% by mass or more and 50% by mass or less, and more preferably 15% by mass or more and 45% by mass or less. If the content is 5% by mass or more, there is a sufficient number of C5-C10 methylene chain structure units that interact with each other, so that the resin in the coating layer is more entangled, strength is maintained, and adhesion is likely to be good even at high temperatures and high humidity. If the content is 55% by mass or less, flexibility of the resin in the coating layer is maintained, and adhesion is likely to be good even at room temperature and at high temperatures and high humidity.
• the content of C5 to C10 methylene chain structures in polycarbonate polyurethane resin (A) is calculated as the mass ratio of C5 to C10 methylene chain structures (-( CH2 ) n- , n is the same as above) to 100g of the total mass of polycarbonate polyurethane resin (A).
• the molecular weight and mol% of each component such as the polycarbonate diol component and diisocyanate component constituting polycarbonate polyurethane resin (A)
• the mol% of the component having a methylene chain having 5 to 10 carbon atoms the proportion of the molecular weight of the methylene chain having 5 to 10 carbon atoms among the molecular weight of the component having a methylene chain having 5 to 10 carbon atoms.
• Polycarbonate polyurethane resin (A) is an addition reaction product of a polycarbonate diol component, a diisocyanate component, and, if necessary, a diol component as a chain extender, at least one of which contains a cyclohexane ring structure and/or a C5-C10 methylene chain structure, and the entire polycarbonate polyurethane resin (A) contains both a cyclohexane ring structure and a C5-C10 methylene chain structure.
• the polycarbonate diol component necessary for preparing the polycarbonate polyurethane resin (A) can be produced by reacting a diol component with a carbonate component.
• the diol component include ethylene glycol, propylene glycol, hexamethylene glycol, neopentyl glycol, 1,2-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, 1,4-cyclohexanediethanol, decamethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexadiol, 2,2-bis(4-hydroxyphenyl)propane, bis(4-hydroxyphenyl)sulfone, etc.
• 1,2-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, and 1,4-cyclohexanediethanol, etc. have the above-mentioned cyclohexane ring structure and are particularly preferred.
• hexamethylene glycol, decamethylene glycol, 1,5-pentanediol, and 1,6-hexadiol, etc. have the above-mentioned C5 to C10 methylene chain structure and are particularly preferred.
• These diol components may be used alone or in combination of two or more.
• the ratio of two or more components to be combined is not particularly limited, and can be adjusted so as to obtain a polycarbonate polyurethane having the required properties.
• the carbonate component include dimethyl carbonate, ethylene carbonate, and phosgene.
• Diisocyanate components necessary for preparing polycarbonate polyurethane resin (A) include, for example, toluene diisocyanate, 4,4'-diphenylmethane diisocyanate, xylylene diisocyanate, naphthalene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, 4,4-methylenebiscyclohexyl diisocyanate, 1,2-bis(isocyanatomethyl)cyclohexane, 1,4-bis(isocyanatomethyl)cyclohexane, etc.
• isophorone diisocyanate 4,4-methylenebiscyclohexyl diisocyanate, 1,2-bis(isocyanatomethyl)cyclohexane, 1,4-bis(isocyanatomethyl)cyclohexane, etc. have the above-mentioned cyclohexane ring structure and are particularly preferred.
• these isocyanate components can be used alone or in combination of two or more. There are no particular limitations on the ratio when combining two or more, and it can be adjusted to obtain a polycarbonate polyurethane that has the required properties.
• polyester resin (B) The polyester resin (B) used in combination with the polycarbonate polyurethane resin (A) has a cyclohexane ring structure and/or a C5 to C10 methylene chain structure in its molecule.
• the content of the cyclohexane ring structure in the polyester resin (B) is usually preferably 5% by mass or more and 20% by mass or less, more preferably 10% by mass or more and 15% by mass or less.
• the content 20% by mass or less it becomes easy to ensure the mobility and flexibility of the resin, and by making it 5% by mass or more, it becomes possible to ensure the number of units of the cyclohexane ring structure that interact with the polycarbonate polyurethane resin (A), thereby ensuring the strength of the resin in the coating layer and making it easy to maintain adhesion under high temperature and high humidity.
• the content of the cyclohexane ring structure in the polyester resin (B) is calculated as the proportion of the mass of the cyclohexane ring structure (-C 6 H 10 -CH 2 -) relative to 100 g of the total mass of the polyester resin (B). Specifically, it can be calculated from "the mol % and molecular weight of each monomer component constituting the polyester resin (B)", “the mol % of the monomer component having a cyclohexane ring among all the monomer components”, and "the proportion of the molecular weight accounted for by the cyclohexane ring structure among the molecular weight of the monomer component having a cyclohexane ring".
• the content of the C5-C10 methylene chain structure in the polyester resin (B) is usually preferably 5% by mass or more and 20% by mass or less, and more preferably 10% by mass or more and 15% by mass or less.
• the content 20% by mass or less it becomes easier to ensure the mobility and flexibility of the resin, and by making it 5% by mass or more, it becomes easier to ensure the number of units of the C5-C10 methylene chain structure that interacts with the polycarbonate polyurethane resin (A), thereby ensuring the strength of the resin in the coating layer and making it easier to maintain adhesion under high temperature and high humidity conditions.
• the content of the C5 to C10 methylene chain structure in polyester resin (B) is calculated as the mass ratio of the C5 to C10 methylene chain structure (-( CH2 ) n- , n is the same as above) to 100 g of the total mass of polyester resin (B). Specifically, it can be calculated from “the mol % and molecular weight of each monomer component constituting said polyester resin (B)", “the mol % of monomer components having a methylene chain having 5 to 10 carbon atoms among all monomer components”, and "the proportion of the molecular weight of the methylene chain having 5 to 10 carbon atoms among the molecular weights of monomer components having a methylene chain having 5 to 10 carbon atoms".
• the polyester resin (B) is a copolymer polyester consisting of a dicarboxylic acid component and a diol component, which is a polycondensation product of a dicarboxylic acid component and a diol component.
• the dicarboxylic acid component and the diol component may each be used alone or in combination of two or more kinds.
• at least one of the dicarboxylic acid component and the diol component has a cyclohexane ring structure and/or a C5-C10 methylene chain structure.
• Dicarboxylic acid components include, for example, terephthalic acid, isophthalic acid, orthophthalic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, diphenylcarboxylic acid, diphenoxyethanedicarboxylic acid, diphenylsulfonecarboxylic acid, anthracenedicarboxylic acid, 1,3-cyclopentanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexa
• the dicarboxylic acid include hexahydroterephthalic acid, hexahydroisophthalic acid, malonic acid, dimethylmalonic acid, cyclohexylmethylmalonic acid, succinic acid, 3,3-diethylsuccinic acid, cyclohexylmethyl
• cyclohexylmethylmalonic acid cyclohexylmethylsuccinic acid
• 1,1-cyclohexanediacetic acid have the above-mentioned cyclohexane ring structure and are particularly preferred.
• Water dispersibility can be imparted to the polyester resin (B).
• a dicarboxylic acid component having a hydrophilic group such as a sulfo group
• dicarboxylic acid components having a hydrophilic group include 5-sulfoterephthalic acid, 5-sulfoisophthalic acid, and salts thereof.
• This dicarboxylic acid component having a hydrophilic group can be copolymerized in the range of 1 to 10 mol % of the total dicarboxylic acid components.
• monocarboxylic acids such as cyclohexylacetic acid may be used in small amounts.
• diol component examples include ethylene glycol, propylene glycol, neopentyl glycol, 1,2-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, 1,4-cyclohexanediethanol, decamethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexadiol, 2,2-bis(4-hydroxyphenyl)propane, bis(4-hydroxyphenyl)sulfone, etc.
• cyclohexane ring structure has the above-mentioned cyclohexane ring structure and are particularly preferred.
• hexamethylene glycol, decamethylene glycol, 1,5-pentanediol, 1,6-hexadiol, and the like have the above-mentioned C5 to C10 methylene chain structure and are particularly preferred.
• the ratio of the dicarboxylic acid component and the diol component when combined is not particularly limited, and can be adjusted to obtain a polyester that has the required properties.
• the binder resin contains polycarbonate polyurethane resin (A) and polyester resin (B).
• the polycarbonate polyurethane resin (A) is usually preferably 35 mass% or more and 85 mass% or less, more preferably 40 mass% or more and 80 mass% or less, and even more preferably 45 mass% or more and 75 mass% or less.
• the polycarbonate polyurethane resin (A) 35 mass% or more, the balance between the flexibility and hardness of the urethane resin can be ensured, and adhesion over time can be ensured.
• it 85 mass% or less the balance between hardness and softness as a coating layer can be maintained and flexibility can be improved, so that it functions best as a coating layer.
• the composition used for forming the coating layer contains a crosslinking agent.
• a crosslinking agent By including a crosslinking agent, it becomes possible to further improve adhesion under high temperature and high humidity.
• Specific examples of the crosslinking agent include isocyanate-based crosslinking agents (especially blocked isocyanate-based crosslinking agents (C) described below) from the viewpoint of the stability over time of the coating liquid and the effect of improving adhesion under high temperature and high humidity treatment.
• a catalyst or the like can be appropriately used as necessary to promote the crosslinking reaction.
• the isocyanate crosslinking agent is preferably a polyisocyanate crosslinking agent having two or more functionalities (furthermore, three or more functionalities).
• the crosslinking agent include polyisocyanate crosslinking agents such as allophanate, biuret, adduct, urtdione, and isocyanurate of polyisocyanate (particularly diisocyanate) compounds.
• polyisocyanate compounds include diisocyanate compounds such as hexamethylene diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, pentamethylene diisocyanate, isophorone diisocyanate, and bis(isocyanatomethyl)cyclohexane.
• one or more polyisocyanate-based crosslinking agents selected from the group consisting of allophanate, biuret, and adduct are preferred because they have small steric hindrance as polymers and easily interact with the structures represented by formulas (1) and (2) derived from the polycarbonate diol that constitutes the polycarbonate polyurethane.
• An allophanate is a compound obtained by forming a urethane from a polyisocyanate and an alcohol, and then reacting this with a polyisocyanate.
• a monohydric alcohol such as 1-butanol
• dicyclohexylmethane-4,4'-diisocyanate is a compound obtained by reacting a monohydric alcohol (such as 1-butanol) with dicyclohexylmethane-4,4'-diisocyanate.
• An adduct is an isocyanate with three or more functionalities obtained by reacting a polyisocyanate with a trifunctional or higher low-molecular-weight active hydrogen-containing compound.
• Examples of such an adduct include a compound obtained by reacting trimethylolpropane with hexamethylene diisocyanate, and a compound obtained by reacting trimethylolpropane with dicyclohexylmethane-4,4'-diisocyanate.
• the reactivity is increased, the crosslinking reaction proceeds more easily, and the crosslink density of the resulting coating layer can be improved, thereby improving the denseness of the resulting coating layer.
• the isocyanate crosslinking agent is preferably a blocked isocyanate crosslinking agent (C) in which a blocking agent is introduced to control the reactivity of isocyanate.
• blocking agents include bisulfite compounds such as sodium bisulfite; pyrazole compounds such as 3,5-dimethylpyrazole, 3-methylpyrazole, 4-bromo-3,5-dimethylpyrazole, and 4-nitro-3,5-dimethylpyrazole; phenols such as phenol and cresol; aliphatic alcohols such as methanol and ethanol; active methylenes such as dimethyl malonate and acetylacetone; mercaptans such as butyl mercaptan and dodecyl mercaptan; acid amides such as acetanilide and acetic acid amide; lactams such as ⁇ -caprolactam and ⁇ -valerolactam; acid imides such as succinimide and maleimide; oximes such as acetaldox
• the above-mentioned blocked isocyanate crosslinking agent (C) has a cyclohexane ring structure and/or a C5-C10 methylene chain structure in its molecule in order to increase the interaction with the resin used in combination.
• the content of the cyclohexane ring structure in the blocked isocyanate crosslinking agent (C) is usually preferably 10% by mass or more and 40% by mass or less, and more preferably 15% by mass or more and 35% by mass or less.
• the content 40% by mass or less it becomes easier to ensure the mobility and flexibility of the crosslinking agent, and by making it 10% by mass or more, it becomes easier to ensure the number of units of the cyclohexane ring structure that interact with the resin, ensure the strength of the resin in the coating layer, and make it easier to maintain adhesion under high temperature and high humidity conditions.
• the content of the cyclohexane ring structure in the blocked isocyanate crosslinking agent (C) is calculated as the proportion of the mass of the cyclohexane ring structure (-C 6 H 10 -CH 2 -) relative to 100 g of the total mass of the blocked isocyanate crosslinking agent (C).
• the content of the C5-C10 methylene chain structure in the blocked isocyanate crosslinking agent (C) is usually preferably 10% by mass or more and 40% by mass or less, and more preferably 15% by mass or more and 35% by mass or less.
• the content 40% by mass or less it becomes easier to ensure the mobility and flexibility of the resin, and by making it 10% by mass or more, it becomes easier to ensure the number of units of the C5-C10 methylene chain structure that interact with the resin, thereby ensuring the strength of the resin in the coating layer and making it easier to maintain adhesion under high temperature and high humidity conditions.
• the content of the C5 to C10 methylene chain structure in the blocked isocyanate crosslinking agent (C) is calculated as the mass ratio of the C5 to C10 methylene chain structure (-( CH2 ) n- , n is the same as above) to the total mass of 100g of the blocked isocyanate crosslinking agent (C).
• the blocked isocyanate crosslinking agent (C) has a cyclohexane ring structure and/or a C5-C10 methylene chain structure in the molecule.
• diisocyanate components that can be used to prepare this blocked isocyanate crosslinking agent (C) include pentamethylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, 4,4-methylenebiscyclohexyl diisocyanate, 1,2-bis(isocyanatomethyl)cyclohexane, 1,4-bis(isocyanatomethyl)cyclohexane, etc.
• isophorone diisocyanate 4,4-methylenebiscyclohexyl diisocyanate, 1,2-bis(isocyanatomethyl)cyclohexane, 1,4-bis(isocyanatomethyl)cyclohexane, etc. are particularly preferred because they have a structure in which at least one hydrogen atom on the cyclohexane ring is substituted with a hydrocarbon group.
• Hexamethylene diisocyanate and the like are particularly preferred because they have a C5 to C10 methylene chain structure.
• isocyanate components may be used alone or in combination of two or more. The ratio of two or more components to be combined is not particularly limited, and can be adjusted so as to obtain an isocyanate-based crosslinking agent that has the required properties.
• the hydrophilic group is preferably an anionic group such as a carboxyl group or a sulfonic acid group, or a nonionic group such as an oxyalkyl group.
• Crosslinking agents having these hydrophilic groups can be prepared by reacting in advance the polyisocyanate that serves as the base of the blocked isocyanate crosslinking agent (C) with a compound having a hydrophilic group and a reactive group such as a hydroxyl group.
• the blocked isocyanate crosslinking agent (C) is preferably a bifunctional or higher (further, trifunctional or higher) blocked isocyanate crosslinking agent, which is an allophanate, biuret, or adduct of a polyisocyanate compound.
• the content of the binder resin is preferably 45 to 95 mass%, more preferably 55 to 90 mass%, even more preferably 60 to 90 mass%, and most preferably 80 to 90 mass%, from the viewpoint of adhesion. If it is 95 mass% or less, the strength of the coating film of the coating layer is maintained and adhesion is good under high temperature and high humidity conditions, and if it is 50 mass% or more, the flexibility of the coating layer is maintained and adhesion is maintained at room temperature and under high temperature and high humidity conditions, which is preferable.
• the content of the blocked isocyanate-based crosslinking agent (C) is preferably 5 to 50 mass%, more preferably 10 to 45 mass%, even more preferably 10 to 40 mass%, and most preferably 10 to 20 mass%.
• the present invention is characterized in that the polycarbonate polyurethane resin (A) used in the coating layer contains a cyclohexane ring structure and a C5-C10 methylene chain structure in the molecule, and the polyester resin (B) and the blocked isocyanate crosslinking agent (C) each contain a cyclohexane ring structure and/or a C5-C10 methylene chain structure, thereby effectively exerting the effects of the present invention.
• the coating layer of the present invention functions optimally as a coating layer because it can improve the flexibility of the resin while maintaining its rigidity as a resin.
• additives such as surfactants, antioxidants, heat stabilizers, weather stabilizers, ultraviolet absorbers, organic lubricants, pigments, dyes, organic or inorganic particles, antistatic agents, nucleating agents, etc. may be added within the range that does not impair the effects of the present invention. However, it is preferable not to use substances that are undesirable from the environmental standpoint, etc.
• particles to be contained in the coating layer include inorganic particles and organic polymer particles.
• inorganic particles include titanium oxide, barium sulfate, calcium carbonate, calcium sulfate, silica, alumina, talc, kaolin, clay, and mixtures thereof.
• inorganic particles can be used in combination with other general inorganic particles such as calcium phosphate, mica, hectorite, zirconia, tungsten oxide, lithium fluoride, calcium fluoride, and others.
• organic polymer particles include polymer particles such as styrene-based, acrylic-based, melamine-based, benzoguanamine-based, and silicone-based particles.
• the average particle size of the inactive particles in the coating layer is preferably 0.04 to 2.0 ⁇ m, and more preferably 0.1 to 1.0 ⁇ m.
• the average particle size of the inactive particles is 0.04 ⁇ m or more, it becomes easy to form irregularities on the surface of the coating layer, which improves the handling properties such as the slipperiness and winding properties of the highly adhesive polyester film, and is preferable because it provides good processability when laminating.
• the average particle size of the inactive particles is 2.0 ⁇ m or less, it is preferable because the particles are less likely to fall off.
• the particle concentration in the coating layer is preferably 1 to 20% by mass relative to the resin content.
• a coating layer forming composition (hereinafter also referred to as "coating liquid") for forming a coating layer may further contain a surfactant for the purpose of improving leveling during coating and degassing the coating liquid.
• the surfactant include cationic, anionic, and nonionic surfactants, and silicone, acetylene glycol, and fluorine-based surfactants are preferred. These surfactants are preferably contained in the coating layer forming composition within a range that does not impair the effect of suppressing iridescent color under a three-wavelength LED light source or the adhesion.
• the coating liquid can be applied to the polyester film by either the so-called in-line coating method, in which the coating is performed simultaneously with the polyester film production, or the so-called off-line coating method, in which the coating is performed using a separate coater after the polyester base film is produced, but the in-line coating method is more efficient and more preferable.
• any known method can be used to apply the coating solution onto the polyester film. Examples include reverse roll coating, gravure coating, kiss coating, die coater, roll brush, spray coating, air knife coating, wire bar coating, pipe doctor, impregnation coating, curtain coating, etc. These methods can be used alone or in combination.
• a method for providing a coating layer on a polyester film includes coating a coating liquid containing a solvent, particles, and resin onto the polyester film and drying the coating.
• the solvent may be water or a mixture of water and an organic solvent, but from an environmental standpoint, water alone or a mixture of water and a water-soluble organic solvent is preferred.
• water-soluble organic solvents include alcohol-based solvents such as isopropyl alcohol and ethanol; ketone-based solvents such as methyl ethyl ketone; ether-based solvents such as butyl cellosolve; amine-based solvents such as triethanolamine; and amide-based solvents such as N-methylpyrrolidone.
• the solids concentration of the coating solution depends on the type of binder resin and the type of solvent, but is preferably 2% by mass or more, and more preferably 4% by mass or more, based on the total mass of the coating solution.
• the solids concentration of the coating solution is preferably 35% by mass or less, and more preferably 15% by mass or less.
• the drying temperature after application also depends on the type of binder resin, the type of solvent, the presence or absence of a crosslinking agent, the solids concentration, etc., but is preferably 80°C or higher and 250°C or lower.
• the coating amount of the coating solution can be adjusted so that the solid content on the polyester film after drying is, for example, 0.03 to 0.24 g/m 2 , and further 0.06 to 0.18 g/m 2.
• the solid content on the polyester film after stretching can be adjusted to be within the above range.
• the stretching process may be either uniaxial or biaxial.
• the polyester film is heated (for example, at 70 to 250°C, preferably 80 to 245°C) while fixed in a tenter, and can then be relaxed at 120 to 250°C.
• the highly adhesive polyester film of the present invention is produced through the coating, drying, stretching, and heat treatment processes.
• the thickness of the coating layer is 30 nm or more and 200 nm or less. If it is adjusted within this range, it is preferable because it is easy to achieve both processability and adhesion. More preferably, it is 50 nm or more and 150 nm or less, and even more preferably, it is 70 nm or more and 100 nm or less. If the thickness of the coating layer is 30 nm or more, it is preferable because it has good adhesion. If the thickness of the coating layer is 200 nm or less, it is preferable because blocking is less likely to occur.
• the thickness of the coating layer was determined by observing the cross section of the cut film with a transmission electron microscope (TEM) and measuring the thickness of the coating layer at 10 random points, averaging the measured thickness.
• TEM transmission electron microscope
• the present invention also provides a laminated polyester film in which a functional layer having various properties is provided on a coating layer of an easily adhesive polyester film.
• the functional layer refers to a layer having functionality such as a hard coat layer, an antiglare layer, an antiglare antireflection layer, an antireflection layer, a low reflection layer, an antistatic layer, etc., for the purpose of preventing reflection, suppressing glare, suppressing rainbow unevenness, suppressing scratches, etc.
• the functional layer may be any of various layers known in the technical field, and the type is not particularly limited.
• a known material for the hard coat layer can be used, and is not particularly limited.
• a resin compound that polymerizes and/or reacts by drying, heat, chemical reaction, or by irradiating with electron beams, radiation, or ultraviolet rays
• curable resins include melamine-based, acrylic-based, silicone-based, and polyvinyl alcohol-based curable resins, but photocurable acrylic-based curable resins are preferred in terms of obtaining high surface hardness or optical design.
• an acrylic-based curable resin a multifunctional (meth)acrylate-based monomer or an acrylate-based oligomer can be used, and examples of the acrylate-based oligomer include polyester acrylate-based, epoxy acrylate-based, urethane acrylate-based, polyether acrylate-based, polybutadiene acrylate-based, and silicone acrylate-based.
• a coating composition for forming the optical functional layer can be obtained.
• the above hard coat layer may have an anti-glare function that scatters external light.
• the anti-glare function is obtained by forming irregularities on the surface of the hard coat layer.
• the haze of the film is ideally 0 to 50%, more preferably 0 to 40%, and particularly preferably 0 to 30%.
• 0% is ideal, and it is acceptable for it to be 0.2% or more, or 0.5% or more.
• layers with different refractive indices can be provided as functional layers to change the light transmission characteristics and suppress light reflection, making it possible to perform anti-reflection processing.
• the refractive index of a functional layer such as a hard coat layer should be adjusted to a reflectance of 0 to 1.0%, more preferably 0 to 0.8%, and particularly preferably 0 to 0.5%.
• 0% is ideal, and it is acceptable for it to be 0.05% or more, or even 0.1% or more.
• the highly adhesive polyester film of the present invention can be used as a polarizer protective film.
• a polarizing plate is formed by disposing polarizer protective films on both sides of a polarizer, and it is preferable that the polarizer protective film on at least one side of the polarizer is the highly adhesive polyester film of the present invention.
• the polarizer protective film on the other side may be the highly adhesive polyester film of the present invention, or may be a film without birefringence, such as a triacetyl cellulose film, an acrylic film, or a norbornene-based film.
• the polarizer may be, for example, a polyvinyl alcohol-based film containing a dichroic material such as iodine.
• the polarizer protective film is attached to the polarizer directly or via an adhesive layer, but from the viewpoint of improving adhesion, it is preferable to attach it via an adhesive. In this case, it is preferable to arrange the coating layer of the easy-adhesive polyester film of the present invention on the polarizer surface or the adhesive layer surface.
• a polarizer that is preferable for bonding the polyester film of the present invention may be, for example, a polarizer obtained by dyeing and adsorbing iodine or a dichroic material to a polyvinyl alcohol-based film, stretching the film uniaxially in an aqueous boric acid solution, and washing and drying the film while maintaining the stretched state.
• the stretching ratio of the uniaxial stretching is usually about 4 to 8 times.
• Polyvinyl alcohol is suitable as the polyvinyl alcohol-based film, and commercially available products such as "Kuraray Vinylon” [manufactured by Kuraray Co., Ltd.], "Tohcello Vinylon” [manufactured by Tohcello Co., Ltd.], and “Nichigo Vinylon” [manufactured by Nippon Synthetic Chemical Industry Co., Ltd.] can be used.
• Dichroic materials include iodine, disazo compounds, polymethine dyes, etc.
• the adhesive layer to be applied to the polarizer is to be thin, it is preferable that the adhesive is water-based, that is, that the adhesive components are dissolved or dispersed in water.
• a composition using polyvinyl alcohol resin, urethane resin, etc. as the main component and blending isocyanate compounds, epoxy compounds, etc. as necessary to improve adhesion can be used.
• the thickness of the adhesive layer is preferably 5 ⁇ m or less, more preferably 3 ⁇ m or less, and even more preferably 1 ⁇ m or less.
• modified polyvinyl alcohol resins such as partially saponified polyvinyl alcohol, fully saponified polyvinyl alcohol, carboxyl group-modified polyvinyl alcohol, acetoacetyl group-modified polyvinyl alcohol, methylol group-modified polyvinyl alcohol, and amino group-modified polyvinyl alcohol may be used.
• concentration of the polyvinyl alcohol resin in the adhesive is preferably 1 to 10% by mass, and more preferably 2 to 7% by mass.
• the thickness of the adhesive layer after curing can be set as desired by designing the properties of the polarizing plate, and a smaller thickness is preferable from the viewpoint of reducing the cost of adhesive materials. In general, it is 0.01 to 20 ⁇ m, preferably 0.1 to 10 ⁇ m, and more preferably 0.5 to 5 ⁇ m. If the adhesive layer is 0.01 ⁇ m or thicker, air bubbles are less likely to be mixed into the adhesive layer, and adhesion and durability are good, which is preferable. If the adhesive layer is 20 ⁇ m or thinner, the reaction rate of the adhesive is sufficient, and the wet heat resistance of the polarizing plate is good, which is preferable.
• the photocurable adhesive preferably contains an epoxy compound that does not contain an aromatic ring as a main component, and also contains a photocationic curable component (I) and a photocationic polymerization initiator (II).
• the photocationically curable component (I) is preferably mainly composed of an epoxy compound that does not contain an aromatic ring.
• An epoxy compound that does not contain an aromatic ring is an epoxy compound other than an aromatic epoxy compound, and is hereinafter referred to as an aliphatic epoxy compound.
• An "epoxy compound” is a compound that has at least one epoxy group in the molecule.
• the aliphatic epoxy compound that is the main component may contain two or more types of epoxy compounds.
• the "main component” means that the content of the aliphatic epoxy compound is 50% by mass or more in 100% by mass of the photocurable adhesive.
• the content of the aliphatic epoxy compound is preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, and even more preferably 90% by mass or more.
• the aliphatic epoxy compound may be an epoxy compound having an alicyclic ring, or it may be an epoxy compound not containing an alicyclic ring and consisting only of a linear hydrocarbon structure and/or a branched hydrocarbon structure.
• the aliphatic epoxy compound may also contain unsaturated bonds such as double bonds, and may further contain heteroatoms (oxygen atoms, nitrogen atoms, sulfur atoms, halogen atoms, etc.) other than the oxygen atom contained in the epoxy group.
• the cationic photopolymerization initiator (II) can initiate cationic polymerization by irradiation with active energy rays, and harden the cationic photocurable component (I) to form an adhesive layer.
• the cationic photopolymerization initiator (II) generates cationic species or Lewis acids when irradiated with active energy rays such as visible light, ultraviolet light, X-rays, or electron beams, and initiates the polymerization reaction of the cationic photocurable component.
• the cationic photopolymerization initiator (II) acts catalytically when exposed to light, and therefore has excellent storage stability and workability even when mixed with the cationic photocurable component.
• photocationic polymerization initiator (II) examples include aromatic diazonium salts; onium salts such as aromatic iodonium salts and aromatic sulfonium salts; and iron-arene complexes.
• aromatic diazonium salts examples include benzenediazonium hexafluoroantimonate, benzenediazonium hexafluorophosphate, and benzenediazonium hexafluoroborate.
• aromatic iodonium salts include diphenyliodonium tetrakis(pentafluorophenyl)borate, diphenyliodonium hexafluorophosphate, diphenyliodonium hexafluoroantimonate, and di(4-nonylphenyl)iodonium hexafluorophosphate.
• Aromatic sulfonium salts include, for example, triphenylsulfonium hexafluorophosphate, triphenylsulfonium tetrakis(pentafluorophenyl)borate, 4,4-bis[diphenylsulfonio]diphenyl sulfide bishexafluorophosphate, 4,4-bis[di( ⁇ -hydroxyethoxy)phenylsulfonio]diphenyl sulfide bishexafluoroantimonate, 4,4-bis[di( ⁇ -hydroxyethoxy)phenylsulfonio]diphenyl sulfide bishexafluorophosphate, 7-[di(p-toluyl)sulfonio]-2-isopropylthio These include xanthone hexafluoroantimonate, 7-[di(p-toluyl)sulfoni
• iron-arene complexes examples include xylene-cyclopentadienyliron(II) hexafluoroantimonate, cumene-cyclopentadienyliron(II) hexafluorophosphate, and xylene-cyclopentadienyliron(II) tris(trifluoromethylsulfonyl)methanide.
• the photocationic polymerization initiator (II) may be used alone or in combination of two or more.
• aromatic sulfonium salts are particularly preferred because they have ultraviolet absorption properties even in the wavelength region around 300 nm, and therefore can provide an adhesive layer with excellent curing properties and good mechanical strength and adhesive strength.
• the content of the photocationic polymerization initiator (II) is preferably 1 to 10 parts by mass, and more preferably 2 to 6 parts by mass, per 100 parts by mass of the total photocationic curable component (I).
• the photocationic curable component (I) can be sufficiently cured, and the obtained polarizing plate can be given high mechanical strength and adhesive strength.
• the content of the photocationic polymerization initiator (II) is preferably 10 parts by mass or less per 100 parts by mass of the photocationic curable component (I).
• the laminated polyester film of the present invention is mainly used for optical films in general, including prism lens sheets, AR (anti-reflection) films, hard coat films, diffusion plates, shatter-proof films, and other base films for optical components in LCDs, flat TVs, CRTs, and other displays, near-infrared absorbing filters that are components for the front panels of plasma displays, and transparent conductive films for touch panels and electroluminescence displays. It can be used suitably for any of these applications.
• Examples of the acrylic resin that is cured by electron beams or ultraviolet rays for forming the above-mentioned functional layer include a composition containing a (meth)acrylate oligomer, which is a reactive oligomer, and a (meth)acrylate-based monomer, which is a reactive monomer (reactive diluent).
• Examples of (meth)acrylate oligomers include compounds in which a reactive (meth)acrylic group is bonded to a (meth)acrylic resin skeleton, polyester acrylate, epoxy acrylate, polyurethane acrylate, silicone acrylate, melamine acrylate, and polyether acrylate.
• Examples of the (meth)acrylate monomer include monofunctional monomers such as ethyl (meth)acrylate and ethylhexyl (meth)acrylate; and polyfunctional monomers such as trimethylolpropane tri(meth)acrylate, hexanediol (meth)acrylate, tripropylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, 1,6-hexanediol di(meth)acrylate, and neopentyl glycol di(meth)acrylate.
• monofunctional monomers such as ethyl (meth)acrylate and ethylhexyl (meth)acrylate
• polyfunctional monomers such as trimethylolpropane tri(meth)acrylate, hexanediol (meth
• a third component can be appropriately added, for example, a relatively low molecular weight polyester resin, polyether resin, acrylic resin, epoxy resin, urethane resin, alkyd resin, spiroacetal resin, polybutadiene resin, polythiolpolyene resin, polyhydric alcohol, etc. can be contained.
• acrylic resin for example, acetophenones, benzophenones, Michler's benzoyl benzoate, ⁇ -amyloxime ester, tetramethylthiuranium monosulfide, and thioxanthones can be used as photopolymerization initiators in the aforementioned resin.
• acetophenones, benzophenones, Michler's benzoyl benzoate, ⁇ -amyloxime ester, tetramethylthiuranium monosulfide, and thioxanthones can be used as photopolymerization initiators in the aforementioned resin.
• a mixture of the photopolymerization initiator and a photosensitizer such as n-butylamine, triethylamine, or tri-n-butylphosphine can be used.
• Silicone-based (siloxane-based) thermosetting resins can be produced by hydrolysis and condensation reactions of a single organosilane compound or a mixture of two or more types in the presence of an acid or base catalyst. In particular, for low reflectance applications, it is even better to mix one or more fluorosilane compounds and carry out hydrolysis and condensation reactions in order to improve low refractive index and contamination resistance, etc.
• a laminated polyester film can be manufactured by providing a functional layer on the coating layer of the highly adhesive polyester film of the present invention. Specific embodiments are described below, but are not limited thereto.
• a functional layer forming composition (functional layer forming coating liquid) is applied to the coating layer surface of the aforementioned highly adhesive polyester film.
• the functional layer forming composition include the aforementioned electron beam or ultraviolet curable acrylic resin (including its oligomer, monomer, etc.) or siloxane-based thermosetting resin.
• the coating layer is provided on both sides of the highly adhesive polyester film, it can be applied to at least one of the coating layer surfaces.
• the functional layer forming coating liquid does not need to be diluted, but there is no problem in diluting it with an organic solvent as required for its viscosity, wettability, coating thickness, etc.
• the coating film can be dried as necessary and then cured by irradiation with electron beams or ultraviolet rays and heating according to the curing conditions to form a functional layer.
• the functional layer-forming coating solution having the above composition is applied onto the coating layer of the highly adhesive polyester film using a wire bar or the like, and the solvent can be removed by drying for 0.5 to 10 minutes at 60 to 100° C.
• the film coated with the functional layer is irradiated with ultraviolet light of 300 mJ/ cm2 using, for example, a high-pressure mercury lamp, to obtain a laminated polyester film having the functional layer.
• the thickness of the functional layer is preferably 1 to 15 ⁇ m. If the thickness of the functional layer is 1 ⁇ m or more, the effects of the functional layer in terms of chemical resistance, scratch resistance, stain resistance, etc. are efficiently exhibited, which is preferable. On the other hand, if the thickness is 15 ⁇ m or less, the flexibility of the functional layer is maintained, and there is no risk of cracks, etc. occurring, which is preferable.
• the laminated polyester film having a functional layer provided on the coating layer of the highly adhesive polyester film of the present invention is preferably highly transparent since it can be used mainly for optical applications.
• the lower limit of the haze is ideally 0%, and the closer to 0%, the more preferable.
• the upper limit of the haze is preferably 2%.
• a haze of 2% or less is preferable because it provides good light transmittance and allows clear images to be obtained in a liquid crystal display device.
• the haze can be measured, for example, according to the method described in the examples below.
• the adhesion between the polyester film and the functional layer in the laminated polyester film can be evaluated by the method described in the examples. Specifically, a laminated polyester film was prepared by forming a functional layer on the coating layer of the highly adhesive polyester film, and the adhesion X (%) was evaluated. Separately, after storing the highly adhesive polyester film for a long period of time, a laminated polyester film was prepared by forming a functional layer on the coating layer, and the adhesion Y (%) was evaluated.
• the long-term storage conditions are preferably measured after being left in a room temperature environment for several weeks to several months, which is the usual storage condition.
• the film is left in a high temperature and high humidity environment of 80° C. and 90% RH for 24 hours, and then left at room temperature (10 to 30° C.) for 12 hours.
• the adhesion X is usually 95% or more, further 98% or more, and particularly 100%.
• the adhesion X is 95% or more, it can be said that the adhesion between the coating layer and the functional layer is sufficiently maintained.
• the adhesion Y after long-term storage is usually 95% or more, more preferably 98% or more, and particularly 100%.
• adhesion Y is 95% or more, it can be said that the adhesion between the coating layer and the functional layer is sufficiently maintained even after long-term storage.
• both adhesion X and adhesion Y are high, and adhesion Y is equal to or hardly changes with adhesion X.
• the highly adhesive polyester film of the present invention has a feature that it has high adhesion reliability with the functional layer, and has high adhesion not only after film formation but also after exposure to a high temperature and high humidity environment (even after long-term storage).
• it has a feature that the adhesion X after film formation is sufficiently high, and the adhesion Y after long-term storage is also high.
• the above-mentioned X (%) and Y (%) satisfy the following formula (1).
• the value of formula (1) is usually 5% or less, preferably 3% or less, and especially 0%. If it is 5% or less, it can be determined that there is no significant difference between the adhesion after film formation and the adhesion after moist heat treatment, and that both are sufficiently adherent. For this reason, it can be determined that even after long-term storage, there is no decrease in the adhesion of the functional layer, and adhesion reliability can be ensured.
• after film formation refers to the time after a coating layer is formed on a polyester film (film formation), and refers to the film being stored in a temperature environment of 40°C or less for a period of up to 6 months after film formation. Within that period, the performance of the coating layer of the highly adhesive polyester film hardly changes.
• the formed highly adhesive polyester film was wound into a roll as an actual product, and left to stand for 6 months in an environment of temperature: 0°C to 30°C and humidity: 10% RH to 80% RH. After that, a sample was taken from the roll, and a functional layer was formed on the coating layer, and the adhesion Z (%) was evaluated.
• the adhesion Z is usually 90% or more, more preferably 95% or more, and particularly 100%. When the adhesion Z is 90% or more, it means that the adhesion Z of the highly adhesive polyester film is maintained and has high adhesion reliability even after being wound into a roll and left for a long period of time.
• Average particle size (measured by scanning electron microscope)
• the average particle size of particles present in the coating layer in the present invention can be measured by the following method: Particles are photographed with a scanning electron microscope (SEM), and the maximum diameters (the distance between the two most distant points) of 300 to 500 particles are measured at a magnification such that the size of the smallest particle is 2 to 5 mm, and the arithmetic average of these is taken as the average particle size.
• SEM scanning electron microscope
• the average particle size of particles can also be determined by dynamic light scattering during the production of particles or films.
• the sol is diluted with a dispersion medium, and the average particle size is obtained by measuring with a submicron particle analyzer N4 PLUS (manufactured by Beckman Coulter) using the parameters of the dispersion medium, and calculating with the cumulant method.
• the average particle size of particles in the sol is observed, and when particles are aggregated, the average particle size of the aggregated particles is observed.
• Adhesion of the functional layer (1) A hard coat layer was formed on the easy-adhesive coating layer of the polyester film obtained in the examples.
• the adhesion between the hard coat layer and the substrate film of the easy-adhesive polyester film on which the hard coat layer was formed was measured in accordance with the description of 8.5.1 of JIS-K5400-1990.
• the coating solution used for forming the hard coat layer was prepared as follows. (Preparation of Coating Solution L for Forming Hard Coat Layer) Methyl ethyl ketone 36.00% by mass Toluene 18.00% by mass Cyclohexanone 6.00% by mass Urethane acrylate 40.00% by mass (BS577 manufactured by Arakawa Chemical) Surfactant: 0.10% by mass Photopolymerization initiator 2.00% by mass (Omnirad184 manufactured by IGM Resins B.V.)
• the easy-adhesive polyester film produced in the examples was stored at a temperature and humidity of 20°C and 65% RH, and 12 hours after film formation, the above-mentioned hard coat layer forming coating solution (L or M) was applied onto the easy-adhesive coating layer using a #14 wire bar, and the coating was dried for 1 minute at 70°C to remove the solvent. Next, the film coated with the hard coat layer was irradiated with 300mJ/ cm2 ultraviolet light using a high-pressure mercury lamp to obtain a hard coat film having a hard coat layer with a thickness of 7 ⁇ m.
• the specific method for measuring the adhesion is as follows. Using a cutter guide with a gap of 2 mm, 100 square-shaped cuts are made on the hard coat layer surface, penetrating the hard coat layer and reaching the base film. Then, a cellophane adhesive tape (manufactured by Nichiban, No. 405; 24 mm wide) is attached to the square-shaped cut surface, and rubbed with an eraser to completely adhere it.
• a cellophane adhesive tape manufactured by Nichiban, No. 405; 24 mm wide
• the cellophane adhesive tape is peeled vertically from the hard coat layer surface of the easy-adhesive polyester film on which the hard coat layer is formed, and the number of squares peeled off from the hard coat layer surface is visually counted, and the adhesion between the hard coat layer and the base film is calculated from the following formula.
• the squares that are partially peeled off are also counted as peeled off squares.
• Adhesion (%) ⁇ 1 - (number of peeled squares/100) ⁇ x 100
• Adhesion of the functional layer (2) A photocurable adhesive layer was formed on the easy-adhesion coating layer of the polyester film obtained in the examples. The adhesion between the photocurable adhesive layer and the substrate film of the easy-adhesion polyester film on which the photocurable adhesive layer was formed was measured in accordance with the description of 8.5.1 of JIS-K5400-1990.
• the coating liquid used for forming the photocurable adhesive layer was prepared as follows. (Preparation of Coating Solution N for Forming Photocurable Adhesive Layer) 3,4-epoxycyclohexylmethyl-3,4'-epoxycyclohexanecarboxylate 23.81% by mass (Daicel Celloxide 2021P) 1,4-cyclohexanedimethanol diglycidyl ether 23.81% by mass (Nagase Chemtex EX-216L) 3-Ethyl-3-[(3-ethyloxetan-3-yl)methoxymethyl]oxetane 47.62% by mass (Aron Oxetane DOX221 manufactured by Toagosei) Cationic initiator 4.76% by weight (Sanapro CPI-100P)
• the aromatic component content in the total resin in the prepared photocurable adhesive layer forming coating solution N was 13.3% in terms of molar ratio.
• the easy-adhesive polyester film produced in the examples described later was stored at a temperature and humidity of 20°C and 65% RH, and 12 hours after film formation, the above-mentioned photocurable adhesive layer-forming coating solution N was applied onto the easy-adhesive coating layer using a #3 wire bar.
• the film coated with the photocurable adhesive layer was irradiated with ultraviolet light of 500 mJ/ cm2 using a high-pressure mercury lamp to obtain a polarizer protective film having a photocurable adhesive layer with a thickness of 5 ⁇ m.
• the specific method for measuring the adhesion is as follows. Using a cutter guide with a gap of 2 mm, 100 grid-like cuts were made on the surface of the photocurable adhesive layer, penetrating the photocurable adhesive layer and reaching the base film. Then, cellophane adhesive tape (manufactured by Nichiban, No. 405; 24 mm wide) was attached to the grid-like cut surface, and rubbed with an eraser to completely adhere it.
• the cellophane adhesive tape was peeled vertically from the photocurable adhesive layer surface of the easy-adhesion polyester film on which the photocurable adhesive layer was formed, and the number of squares peeled off from the photocurable adhesive layer surface was visually counted, and the adhesion between the photocurable adhesive layer and the base film was calculated from the following formula.
• the squares that were partially peeled off were also counted as peeled squares.
• Adhesion (%) ⁇ 1 - (number of peeled squares/100) ⁇ x 100
• Polyester Resin Composition Polyester resin was dissolved in deuterated chloroform and subjected to 1 H-NMR analysis using a Varian Gemini-200 nuclear magnetic resonance analyzer (NMR), and the mole percentage ratio of each component was determined from the integral ratio.
• NMR Varian Gemini-200 nuclear magnetic resonance analyzer
• PCPU-1 polyurethane resin
• PCPU-1 polyurethane resin
• PCPU-1 polyurethane resin
• the proportion (content) of cyclohexane ring structures in the entire polycarbonate polyurethane (PCPU-1) was 29.1% by mass, and the proportion (content) of methylene chain structures having 5 to 10 carbon atoms was 8.5% by mass.
• PCPU-1WD Water Dispersion
• PCPU-1WD Polyurethane Resin
• (PCPU-2) was prepared in the same manner as the synthesis of (PCPU-1) above, and aqueous dispersion (PCPU-2WD) was obtained in the same manner as the preparation of (PCPU-1WD).
• the proportion (content) of cyclohexane ring structures in the entire polycarbonate polyurethane (PCPU-2) was 10.8% by mass, and the proportion (content) of methylene chain structures having 5 to 10 carbon atoms was 11.2% by mass.
• (PCPU-3) was prepared in the same manner as in the synthesis of (PCPU-1) above, except that the isocyanate used was changed from 4,4'-diphenylmethane diisocyanate to dicyclohexylmethane-4,4'-diisocyanate, and water dispersion (PCPU-3WD) was obtained in the same manner as in the preparation of (PCPU-1WD).
• the proportion (content) of cyclohexane ring structures in the entire polycarbonate polyurethane (PCPU-3) was 39.5% by mass, and the proportion (content) of methylene chain structures having 5 to 10 carbon atoms was 8.4% by mass.
• (PCPU-4) was prepared in the same manner as in the synthesis of (PCPU-1) above, except that the isocyanate used was changed from 4,4'-diphenylmethane diisocyanate to cyclohexane-1,2-diylbis(methylene) diisocyanate, and aqueous dispersion (PCPU-4WD) was obtained in the same manner as in the preparation of (PCPU-1WD).
• the proportion (content) of cyclohexane ring structures in the entire polycarbonate polyurethane (PCPU-4) was 42.8% by mass, and the proportion (content) of methylene chain structures having 5 to 10 carbon atoms was 9.1% by mass.
• (PCPU-7) was prepared in the same manner as in the synthesis of (PCPU-6) above, except that the isocyanate used was changed from dicyclohexylmethane-4,4'-diisocyanate to 4,4'-diphenylmethane diisocyanate, and aqueous dispersion (PCPU-7WD) was obtained in the same manner as in the preparation of (PCPU-1WD).
• the proportion (content) of cyclohexane ring structures in the entire polycarbonate polyurethane (PCPU-7) was 0.0 mass%
• the proportion (content) of methylene chain structures having 5 to 10 carbon atoms was 0.0 mass%.
• polyester resin Preparation of polyester resin (PEs-1): A polyester resin (PEs-1) was polymerized according to a known polymerization method. The composition of the obtained polymer was analyzed by 1 H-NMR, and the mole percentage ratio of each component was determined from the integral ratio. The results are shown in Table 1. The reduced viscosity of the obtained polyester resin was 0.583 dl/g. The abbreviations given in Table 1 are listed below.
• TPA terephthalic acid
• IPA isophthalic acid
• CHMM cyclohexylmethylmalonic acid
• DSS dimethyl-5-sodium sulfoisophthalate
• EG ethylene glycol HD: 1,6-hexanediol
• DEG diethylene glycol
• NPG neopentyl glycol
• CHDM 1,4-cyclohexanedimethanol
• polyester water dispersion (PEs-1WD): In a reactor equipped with a stirrer, a thermometer and a reflux device, 30 parts by mass of copolymerized polyester resin (PEs-1) and 15 parts by mass of ethylene glycol-n-butyl ether were placed, heated at 110°C and stirred to dissolve the resin. After the resin was completely dissolved, 55 parts by mass of water was gradually added to the polyester solution while stirring. After the addition, the liquid was cooled to room temperature while stirring to produce a milky white polyester resin (PEs-1) water dispersion (PEs-1WD) with a solid content of 25.1% by mass. The liquid viscosity of the obtained water dispersion was 84 mPa ⁇ s.
• polyester resin (PEs-2) and preparation of polyester water dispersion (PEs-2WD): Similarly to the polymerization of the polyester resin (PEs-1) described above, a polyester resin (PEs-2) was produced according to a known polymerization method. As with PEs-1, the composition ratio was determined, and the reduced viscosity of the resulting resin was evaluated. The results are shown in Table 1. The proportion (content) of cyclohexane ring structures in the entire polyester (PEs-2) was 12.8% by mass, and the proportion (content) of methylene chain structures having 5 to 10 carbon atoms was 0.0% by mass.
• a polyester water dispersion (PEs-2WD) was prepared in the same manner as in the preparation of the polyester water dispersion (PEs-1WD) described above.
• the solid content and liquid viscosity were evaluated in the same manner as in the preparation of PEs-1WD. The results are shown in Table 2.
• a polyester resin (PEs-3) was produced according to a known polymerization method similar to the polymerization of the polyester resin (PEs-1) described above. As with PEs-1, the composition ratio was determined and the reduced viscosity of the resulting resin was evaluated. The results are shown in Table 1. The proportion (content) of cyclohexane ring structures in the entire polyester (PEs-3) was 0.0 mass %, and the proportion (content) of methylene chain structures having 5 to 10 carbon atoms was 18.2 mass %. A polyester water dispersion (PEs-3WD) was prepared in the same manner as in the preparation of the polyester water dispersion (PEs-1WD) described above. The solid content and liquid viscosity were evaluated in the same manner as in the preparation of PEs-1WD. The results are shown in Table 2.
• polyester resin (PEs-4) and preparation of polyester water dispersion (PEs-4WD): Similarly to the polymerization of the above-mentioned polyester resin (PEs-1), a polyester resin (PEs-4) was produced according to a known polymerization method. As with PEs-1, the composition ratio was determined, and the reduced viscosity of the resulting resin was evaluated. The results are shown in Table 1. The proportion (content) of cyclohexane ring structures in the entire polyester (PEs-4) was 10.7% by mass, and the proportion (content) of methylene chain structures having 5 to 10 carbon atoms was 15.1% by mass.
• a polyester water dispersion (PEs-4WD) was prepared in the same manner as in the preparation of the polyester water dispersion (PEs-1WD) described above.
• the solid content and liquid viscosity were evaluated in the same manner as in the preparation of PEs-1WD. The results are shown in Table 2.
• polyester resin (PEs-5) and preparation of polyester water dispersion (PEs-5WD) A polyester resin (PEs-5) was produced according to a known polymerization method similar to the polymerization of the polyester resin (PEs-1) described above. As with PEs-1, the composition ratio was determined and the reduced viscosity of the resulting resin was evaluated. The results are shown in Table 1. The proportion (content) of cyclohexane ring structures in the entire polyester (PEs-5) was 11.5% by mass, and the proportion (content) of methylene chain structures having 5 to 10 carbon atoms was 17.6% by mass. A polyester water dispersion (PEs-5WD) was prepared in the same manner as in the preparation of the polyester water dispersion (PEs-1WD) described above. The solid content and liquid viscosity were evaluated in the same manner as in the preparation of PEs-1WD. The results are shown in Table 2.
• a polyester resin (PEs-6) was produced according to a known polymerization method similar to the polymerization of the polyester resin (PEs-1) described above. As with PEs-1, the composition ratio was determined and the reduced viscosity of the resulting resin was evaluated. The results are shown in Table 1. The proportion (content) of cyclohexane ring structures in the entire polyester (PEs-6) was 11.4 mass%, and the proportion (content) of methylene chain structures having 5 to 10 carbon atoms was 18.9 mass%.
• a polyester water dispersion (PEs-6WD) was prepared in the same manner as in the preparation of the polyester water dispersion (PEs-1WD) described above. The solid content and liquid viscosity were evaluated in the same manner as in the preparation of PEs-1WD. The results are shown in Table 2.
• a polyester resin (PEs-7) was produced according to a known polymerization method similar to the polymerization of the polyester resin (PEs-1) described above. As with PEs-1, the composition ratio was determined and the reduced viscosity of the resulting resin was evaluated. The results are shown in Table 1. Here, the proportion (content) of cyclohexane ring structures in the entire polyester (PEs-7) was 0 mass %, and the proportion (content) of methylene chain structures having 5 to 10 carbon atoms was 0 mass %.
• a polyester water dispersion (PEs-7WD) was prepared in the same manner as in the preparation of the polyester water dispersion (PEs-1WD) described above.
• the solid content and liquid viscosity were evaluated in the same manner as in the preparation of PEs-1WD. The results are shown in Table 2.
• Polyisocyanate compounds Polyisocyanate compound (PI-1): A polyisocyanate compound (PI-1) having a biuret structure was produced using dicyclohexylmethane-4,4'-diisocyanate with reference to JP-A-8-225511. The NCO concentration of this polyisocyanate compound was 16.0 wt%. The proportion (content) of cyclohexane ring structures was 37.0 mass%, and the proportion (content) of methylene chain structures having 5 to 10 carbon atoms was 0.0 mass%.
• Polyisocyanate compound (PI-2) A polyisocyanate compound (PI-2) having a biuret structure similar to that of the polyisocyanate compound (PI-1) was produced using cyclohexane-1,2-diylbis(methylene)diisocyanate instead of dicyclohexylmethane-4,4'-diisocyanate.
• the NCO concentration of this polyisocyanate compound was 21.6 wt%.
• the proportion (content) of cyclohexane ring structures was 50.0 mass%, and the proportion (content) of methylene chain structures having 5 to 10 carbon atoms was 0.0 mass%.
• Polyisocyanate compound (PI-3) A polyisocyanate compound (PI-3) having a biuret structure was produced in the same manner as in the polyisocyanate compound (PI-1) except that hexamethylene diisocyanate was used instead of dicyclohexylmethane-4,4'-diisocyanate.
• the NCO concentration of this polyisocyanate compound was 25.0 wt%.
• the proportion (content) of cyclohexane ring structures was 0.0 mass%, and the proportion (content) of methylene chain structures having 5 to 10 carbon atoms was 50.0 mass%.
• Polyisocyanate adduct (PI-4) A polyisocyanate adduct (PI-4) was produced using trimethylolpropane and dicyclohexylmethane-4,4'-diisocyanate with reference to JP-A-7-118364.
• the NCO concentration of this polyisocyanate compound was 13.7 wt%.
• the proportion (content) of cyclohexane ring structures was 31.6 mass%, and the proportion (content) of methylene chain structures having 5 to 10 carbon atoms was 0.0 mass%.
• Polyisocyanate compound (PI-5) With reference to JP 1996-245544 A, a polyisocyanate compound (PI-5) having an allophanate structure was produced using 1-butanol and dicyclohexylmethane-4,4'-diisocyanate. The NCO concentration of this polyisocyanate compound was 9.0 wt%. The proportion (content) of cyclohexane ring structures was 31.2 mass%, and the proportion (content) of methylene chain structures having 5 to 10 carbon atoms was 0.0 mass%.
• Polyisocyanate compound (PI-6) A polyisocyanate compound (PI-6) having an isocyanurate structure was produced using dicyclohexylmethane-4,4'-diisocyanate with reference to JP 2003-268065 A.
• the NCO concentration of this polyisocyanate compound was 16.0 wt %.
• the proportion (content) of cyclohexane ring structures was 37.0 mass %, and the proportion (content) of methylene chain structures having 5 to 10 carbon atoms was 0.0 mass %.
• Polyisocyanate compound (PI-7) A polyisocyanate compound (PI-7) having an isocyanurate structure similar to that of the polyisocyanate compound (PI-6) was produced using hexamethylene diisocyanate instead of dicyclohexylmethane-4,4'-diisocyanate.
• the NCO concentration of this polyisocyanate compound was 25.0 wt%.
• the proportion (content) of cyclohexane ring structures was 0.0 mass%, and the proportion (content) of methylene chain structures having 5 to 10 carbon atoms was 50.0 mass%.
• Polyisocyanate compound (PI-8) A polyisocyanate compound (PI-8) having an isocyanurate structure similar to that of the polyisocyanate compound (PI-6) was produced using 4,4'-diphenylmethane diisocyanate instead of dicyclohexylmethane-4,4'-diisocyanate.
• the NCO concentration of this polyisocyanate compound was 16.8 wt%, and the proportion (content) of cyclohexane ring structures was 0 mass%, and the proportion (content) of methylene chain structures having 5 to 10 carbon atoms was 0 mass%.
• C-1WD Preparation of Water Dispersion (C-1WD) of Blocked Isocyanate Crosslinking Agent (C-1): A flask equipped with a stirrer, a thermometer, and a reflux condenser was charged with 140.1 parts by mass of a polyisocyanate compound (PI-1) having a biuret structure made from dicyclohexylmethane-4,4'-diisocyanate, 50.0 parts by mass of dipropylene glycol dimethyl ether, and 53.9 parts by mass of 3,5-dimethylpyrazole, and the mixture was stirred at 70°C under a nitrogen atmosphere for 2 hours.
• PI-1 polyisocyanate compound having a biuret structure made from dicyclohexylmethane-4,4'-diisocyanate
• 50.0 parts by mass of dipropylene glycol dimethyl ether 53.9 parts by mass of 3,5-dimethylpyrazole
• the reaction solution was then subjected to infrared spectroscopy to confirm that the absorption of the isocyanate group had disappeared.
• the concentration was adjusted with water to prepare an aqueous dispersion (C-1WD) of a blocked isocyanate-based crosslinking agent (C-1) having a solid content of 30.0% by mass.
• the proportion (content) of cyclohexane ring structures in the solid content of this blocked isocyanate crosslinking agent (C-1) was 26.7 mass%, and the proportion (content) of methylene chain structures having 5 to 10 carbon atoms was 0 mass%.
• the proportion (content) of cyclohexane ring structures in the solid content of the blocked isocyanate crosslinking agent (C-2) was 32.9% by mass, and the proportion (content) of methylene chain structures with 5 to 10 carbon atoms was 0% by mass.
• the proportion (content) of cyclohexane ring structures in the solid content of the blocked isocyanate crosslinker (C-3) was 0% by mass, and the proportion (content) of methylene chain structures with 5 to 10 carbon atoms was 31.3% by mass.
• the proportion (content) of cyclohexane ring structures in the solid content of the blocked isocyanate crosslinker (C-4) was 23.8% by mass, and the proportion (content) of methylene chain structures with 5 to 10 carbon atoms was 0% by mass.
• the proportion (content) of cyclohexane ring structures in the solid content of the blocked isocyanate crosslinker (C-5) was 25.6% by mass, and the proportion (content) of methylene chain structures with 5 to 10 carbon atoms was 0% by mass.
• the proportion (content) of cyclohexane ring structures in the solid content of the blocked isocyanate crosslinker (C-6) was 26.7% by mass, and the proportion (content) of methylene chain structures with 5 to 10 carbon atoms was 0% by mass.
• the proportion (content) of cyclohexane ring structures in the solid content of the blocked isocyanate crosslinker (C-7) was 0% by mass, and the proportion (content) of methylene chain structures with 5 to 10 carbon atoms was 31.3% by mass.
• the proportion (content) of cyclohexane ring structures in the solid content of the blocked isocyanate crosslinker (C-8) was 0% by mass, and the proportion (content) of methylene chain structures with 5 to 10 carbon atoms was 0% by mass.
• Example 1 (Preparation of Coating Solution) A coating solution having the following composition was prepared. Water 43.47 parts by weight Isopropyl alcohol 30.57 parts by weight Silica sol 4.15 parts by weight (silica sol with an average particle size of 100 nm, solid content concentration 10.5% by weight) PCPU-1WD 5.42 parts by mass (solid content concentration 35.0 mass%) PEs-1WD 7.58 parts by mass (solid content concentration 25.1% by mass) C-1WD 8.43 parts by mass (solid concentration 30.0% by mass) Surfactant: 0.05 parts by weight (silicon-based, solids concentration: 10.0% by weight) High boiling point solvent 0.34 parts by mass
• PET polyethylene terephthalate
• the pellets were fed to an extruder, melt-extruded into a sheet at about 280° C., and rapidly cooled and solidified on a rotating cooling metal roll maintained at a surface temperature of 20° C. to obtain an unstretched PET sheet.
• the above coating solution was applied to one side of a PET film by roll coating, and then dried at 80° C., and the coating amount after final stretching and drying was adjusted to 0.12 g/m 2. Subsequently, the film was stretched 4.0 times in the width direction at 150° C. in a tenter, heated at 230° C. while the length of the film in the width direction was fixed, and further subjected to a relaxation treatment in the width direction at 230° C. to obtain an easily adhesive polyester film having a thickness of 50 ⁇ m.
• the thickness of the adhesive coating layer on the resulting adhesive polyester film was 80 nm, and the film haze was 0.66%.
• a functional layer-forming coating liquid (coating liquids L and M for forming a hard coat layer in (4) above, and coating liquid N for forming a photocurable adhesive layer in (5) above) was used on the adhesive coating layer of the adhesive polyester film, and a laminated polyester film having a functional layer was obtained according to the formation method described above.
• the adhesion strength X was 96%.
• the above-mentioned easy-adhesive polyester film was left in a high-temperature, high-humidity chamber under an environment of 80°C and 90% RH for 24 hours, and then left at room temperature for 12 hours. After that, a functional layer was formed on the easy-adhesive coating layer of the treated easy-adhesive polyester film using a functional layer-forming coating liquid (same as above), to obtain a laminated polyester film.
• the adhesion strength Y was 95%.
• the above-mentioned adhesive polyester film that had not been subjected to high temperature and humidity treatment was rolled up and left for 6 months in an environment with a temperature of 0°C to 30°C and a humidity of 10% RH to 80% RH. After leaving it, a sample of the adhesive polyester film was taken from the roll and its adhesion was evaluated in the same manner as above.
• adhesion Z The evaluation results of adhesion of the samples from the roll (adhesion Z) are shown in Table 3. Regarding adhesion reliability based on these results, samples that could guarantee 100% or more adhesion were rated as "A”, samples that could guarantee adhesion of 95% or more but less than 100% were rated as "B”, samples that could guarantee adhesion of 90% or more but less than 95% were rated as "C”, and samples that had less than 90% adhesion were rated as "D”. The evaluation results of adhesion reliability are shown in the adhesion reliability column in Table 3. Samples that could guarantee adhesion of 90% or more for Z can be confirmed as having guaranteed adhesion reliability.
• adhesion Z was 92%, resulting in adhesion reliability of "C" and it was determined that adhesion reliability was guaranteed.
• Examples 2 to 14 A highly adhesive polyester film was obtained in the same manner as in Example 1, except that the polycarbonate polyurethane resin, polyester resin, and crosslinking agent used were changed to the combinations shown in Table 3.
• Example 3 The obtained highly adhesive polyester film was evaluated in the same manner as in Example 1, and then a laminated polyester film with a functional layer was obtained in the same manner as in Example 1. The various evaluation results are shown in Table 3.
• Example 15 and 16 Except for changing the thickness of the coating solution to that shown in Table 3, the same procedure as in Example 11 was carried out to obtain a highly adhesive polyester film.
• Example 3 The obtained highly adhesive polyester film was evaluated in the same manner as in Example 1, and then a laminated polyester film with a functional layer was obtained in the same manner as in Example 1. The various evaluation results are shown in Table 3.
• Examples 17 to 18 The same evaluations as in Example 1 were carried out except that the functional layer shown in Table 3 was added to the highly adhesive polyester film prepared in the same manner as in Example 11. The various evaluation results are as shown in Table 3.
• Example 3 The obtained highly adhesive polyester film was evaluated in the same manner as in Example 1, and then a laminated polyester film with a functional layer was obtained in the same manner as in Example 1. The various evaluation results are shown in Table 3.
• the highly adhesive polyester film of the present invention has excellent adhesion between the functional layer and the polyester film (especially adhesion after long-term storage, etc.), and has high adhesion reliability. It also has excellent blocking resistance and transparency. Therefore, it can be widely used in optical applications, etc.

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