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
  • 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
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
  • C08G18/40—High-molecular-weight compounds
  • C08G18/42—Polycondensates having carboxylic or carbonic ester groups in the main chain
  • C08G18/44—Polycarbonates
• • 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
  • C08J7/046—Forming abrasion-resistant coatings; Forming surface-hardening coatings
• • 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
• • 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
  • C09D5/002—Priming paints
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
  • C09J7/00—Adhesives in the form of films or foils
  • C09J7/20—Adhesives in the form of films or foils characterised by their carriers
  • C09J7/22—Plastics; Metallised plastics
  • C09J7/25—Plastics; Metallised plastics based on macromolecular compounds obtained otherwise than by reactions involving only carbon-to-carbon unsaturated bonds
  • C09J7/255—Polyesters
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
  • C09J7/00—Adhesives in the form of films or foils
  • C09J7/50—Adhesives in the form of films or foils characterised by a primer layer between the carrier and the adhesive
• • 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
  • G02B1/04—Optical elements characterised by the material of which they are made; Optical coatings for optical elements made of organic materials, e.g. plastics
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B5/00—Optical elements other than lenses
  • G02B5/30—Polarising elements
• • 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
  • C08J2367/00—Characterised by the use of polyesters obtained by reactions forming a carboxylic ester link in the main chain; 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
  • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
  • C09J2475/00—Presence of polyurethane
  • C09J2475/003—Presence of polyurethane in the primer coating

Definitions

• the present invention relates to a laminated polyester film. More specifically, the present invention relates to an easily adhesive polyester film that has excellent adhesion to various functional layers, anti-blocking properties, and transparency, and is suitably used in optical applications.
• Hard coat films which are laminated with transparent hard coat layers, are used on the front surfaces of displays such as touch panels, computers, televisions, liquid crystal displays, decorative materials, etc.
• liquid crystal panel components used in displays are bonded together with hard coat films and polarizers, or bonded with other components. conduct.
• a transparent polyester film is generally used as a transparent plastic film as a base material, and polyester is used as an intermediate layer to improve the adhesion between the polyester film as a base material and the hard coat layer or adhesive.
• a coating layer having easy adhesion properties is often provided on the surface of the film.
• the above-mentioned hard coat film is required to have durability against temperature, humidity, light, transparency, chemical resistance, scratch resistance, stain resistance, etc.
• a multilayer anti-reflection structure in which a high refractive index layer and a low refractive index layer are mutually laminated on top of the hard coat layer. It is also common practice to provide layers.
• the adhesive which is required to have durability against temperature, humidity, light, transparency, chemical resistance, scratch resistance, stain resistance, etc.
• adhesives having various skeletons have been developed, and the adhesion between the base material and the adhesive has been discussed each time.
• materials bonded together with adhesives are required to be reliable for long-term use of LCD TVs, such as moisture and heat resistance, adhesion retention, and adhesion retention over time. It is required to be a product.
• a liquid crystal display device has polarizing plates placed on both sides of a glass substrate that forms the surface of the liquid crystal panel.
• a polarizing plate generally has a structure in which a polarizer protective film is bonded to both sides of a polarizer made of a polyvinyl alcohol film and a dichroic material such as iodine via a hydrophilic adhesive such as a polyvinyl alcohol resin.
• Triacetyl cellulose films have traditionally been used as protective films for protecting polarizers from the viewpoint of optical properties and transparency.
• triacetylcellulose does not have sufficient durability, and when a polarizing plate using triacetylcellulose film as a polarizer protective film is used at high temperature or high humidity, the performance of the polarizing plate, such as the degree of polarization and hue, decreases. There are cases. Furthermore, in recent years, there has been a demand for thinner polarizing plates in response to thinner displays, but there has been a limit to how thin triacetylcellulose films can be made from the perspective of maintaining moisture barrier properties. Therefore, it has been proposed to use a polyester film as a polarizer protective film having durability and moisture barrier properties (see, for example, Patent Document 1).
• the triacetylcellulose film used as a polarizer protective film has been subjected to alkali treatment on its surface and has extremely high affinity with hydrophilic adhesives. Therefore, a protective film made of triacetylcellulose film has extremely high adhesiveness to a polarizer coated with a hydrophilic adhesive.
• polyester films have insufficient adhesion with hydrophilic adhesives, and this tendency is particularly noticeable in the case of polyester films that have been oriented by stretching. Therefore, in order to improve the adhesion with the polarizer or the hydrophilic adhesive applied to the polarizer, the surface of the polyester film is coated with a highly hydrophilic material such as the easy-adhesion layer disclosed in Patent Document 1. has been carried out.
• JP2013-063610A Japanese Patent Application Publication No. 2011-246663 Japanese Patent Application Publication No. 2011-168053
• an object of the present invention is to provide an easily adhesive polyester film that has improved adhesion between a functional layer such as a hard coat layer or an adhesive and a polyester film serving as a base material, and is suitable for optical applications.
• An object of the present invention is to provide an easily adhesive polyester film that can be used.
• the present inventor has conducted intensive studies to achieve the above object, and as a result, has arrived at the present invention.
• the present invention consists of the following configuration.
• An easily adhesive polyester film having a coating layer on at least one surface of the polyester film, wherein the coating layer contains a block isocyanate type C selected from polycarbonate polyurethane and allophanate, biuret, or adduct form of hexamethylene diisocyanate.
• An easily adhesive polyester film which is formed from a polycarbonate polyurethane, and has a content of n-hexamethylene chains present at the ⁇ -position of carbonate bonds in the polycarbonate polyurethane of 3% by mass or more and 20% by mass or less based on the mass of the polycarbonate polyurethane. .
• an easily adhesive polyester film that has excellent adhesion between a functional layer such as a hard coat layer or an adhesive and a base polyester film, particularly after long-term storage, and has adhesion reliability. , it can be widely applied to optical applications, etc.
• polyester film used as a base material in 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.
• the polyester resin contains 50% by mass or more, and when copolymerized with other monomers, it means that the polyester structural unit is 50% or more. It means containing mol% or more.
• the polyester film contains polyester resin in an amount of 90% by mass or more, more preferably 95% by mass or more, still more preferably 100% by mass.
• the material of the polyester resin 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 include terephthalic acid, isophthalic acid, orthophthalic acid, 2,5-naphthalene dicarboxylic acid, 2,6-naphthalene dicarboxylic acid, 1,4-naphthalene dicarboxylic acid, 1,5-naphthalene dicarboxylic acid, diphenyl Carboxylic acid, diphenoxyethanedicarboxylic acid, diphenylsulfonecarboxylic acid, anthracenedicarboxylic acid, 1,3-cyclopentanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, hexahydroterephthalic acid, hexahydro I
• diol components constituting the polyester resin include ethylene glycol, propylene glycol, hexamethylene glycol, neopentyl glycol, 1,2-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, decamethylene glycol, and 1,3-cyclohexanedimethanol.
• diol components constituting the polyester resin include propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexadiol, 2,2-bis(4-hydroxyphenyl)propane, and bis(4-hydroxyphenyl)sulfone.
• each of the dicarboxylic acid component and diol component constituting the polyester resin may be used alone or in combination of two or more. Further, other acid components such as trimellitic acid and other hydroxyl components such as trimethylolpropane may be added as appropriate.
• polyester resin examples 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. It is also a preferred embodiment to include other copolymer components or other polymers in order to control optical properties such as polarization. From the viewpoint of controlling the optical properties of the polyester film, preferred copolymerization components include diethylene glycol and copolymerization components having norbornene in the side chain.
• inert particles are sometimes incorporated into the film, but in order to maintain high transparency, it is necessary to incorporate inert particles into the film. It is preferable that the content is as small as possible. Therefore, either the film has a multilayer structure in which particles are contained only in the surface layer, or the film does not contain particles substantially, and particles are contained only in the coating layer laminated on at least one side of the polyester film. is preferred.
• substantially no particles are contained means, for example, in the case of inorganic particles, when an element derived from the particles is quantitatively analyzed by X-ray fluorescence analysis, it is 50 ppm or less, preferably 10 ppm or less, most preferably detected. It means the content below the limit. Even if particles are not actively added to the base film, contaminants derived from foreign substances and dirt adhering to the raw resin or the lines and equipment in the film manufacturing process will inevitably peel off and form into the film. This is because they may be mixed in with other substances.
• a polyester film has a multilayer structure
• a two-layer three-layer structure in which the inner layer does not substantially contain inert particles and only the outermost layer contains inert particles achieves both transparency and processability. is possible and preferred.
• the polyester film serving as the base material may be a single layer or a laminate of two or more layers.
• various additives can be included in the film as needed, as long as they are within the range that provides the effects of the present invention.
• additives include antioxidants, light stabilizers, antigelation agents, organic wetting agents, antistatic agents, ultraviolet absorbers, and surfactants.
• the film has a laminated structure, it is also preferable to contain additives depending on the function of each layer as necessary. For example, in order to prevent photodeterioration of the polarizer, it is also a preferred embodiment to add an ultraviolet absorber or the like to the inner layer.
• a polyester film can be manufactured according to a conventional method. For example, it can be obtained by melt-extruding the above-mentioned polyester resin into a film and cooling and solidifying it in a casting drum to form a film.
• the polyester film in the present invention either an unstretched film or a stretched film can be used, but a stretched film is preferable from the viewpoint of durability such as mechanical strength and chemical resistance.
• the stretching method is not particularly limited, and a longitudinal uniaxial stretching method, a transverse uniaxial stretching method, a longitudinal and lateral sequential biaxial stretching method, a longitudinal and lateral simultaneous biaxial stretching method, etc. can be adopted.
• the stretching may be performed before laminating the easily adhesive coating layer described below, or after laminating the easily adhesive coating layer. It is also possible to uniaxially stretch in the vertical or horizontal direction before laminating the easily adhesive coating layer, and to stretch in the other direction after laminating the coating layer.
• the easily adhesive polyester film of the present invention preferably has an easily adhesive coating layer laminated on the polyester base film as described above.
• a binder resin and additives can be included in the coating layer.
• a resin having easy adhesive properties is suitable.
• polycarbonate polyurethane which is a urethane resin having a polycarbonate structure
• the functional layer is formed by a curing reaction by UV irradiation, has a polycarbonate structure that easily forms radicals when exposed to UV irradiation, and has a certain degree of flexibility. This seems to be due to the fact that it is a urethane resin that maintains rigidity.
• the polycarbonate polyurethane preferably has a structure having an n-hexamethylene chain at the ⁇ -position of the carbonate bond, and when the polycarbonate polyurethane is 100% by mass, the content of n-hexamethylene chains is 3% by mass or more.
• the content is preferably 20% by mass or less, more preferably 5% by mass or more and 18% by mass or less, particularly preferably 7% by mass or more and 16% by mass or less.
• the content of the n-hexamethylene chain located at the ⁇ -position of the carbonate bond is 20% by mass or less, since adhesiveness with the functional layer is maintained under high temperature and high humidity.
• the content is 3% by mass or more, a balance between flexibility and rigidity is maintained, and adhesion to the polyester base film is easily maintained at room temperature and under high temperature and high humidity conditions, which is preferable.
• the polycarbonate polyurethane is preferably formed from a polycarbonate diol and a polyisocyanate, and the n-hexamethylene chain is preferably provided as the diol component of the polycarbonate diol. It is also preferable that the polycarbonate diol contains a diol component other than the diol component having an n-hexamethylene chain.
• Diol components other than the diol component having an n-hexamethylene chain are not particularly limited, and include, for example, ethylene glycol, propylene glycol, hexamethylene glycol, neopentyl glycol, 1,2-cyclohexanedimethanol, 1,4 -Cyclohexane dimethanol, decamethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 2,2-bis(4-hydroxyphenyl)propane, bis(4-hydroxyphenyl) Examples include sulfone.
• 1,2-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol and the like are easily used and are preferably mixed.
• the reason why the effect of the present invention is exhibited by suppressing the n-hexamethylene chain within a certain range is estimated as follows.
• the rigidity of the resin is maintained and the flexibility of the resin is also improved. As a result, it was found that not only the initial adhesion with the functional layer as an adherend can be satisfied, but also the retention of adhesion over time can be improved.
• the crosslinking agent included in the composition forming the coating layer is preferably a blocked isocyanate-based crosslinking agent such as hexamethylene diisocyanate.
• a blocked isocyanate-based crosslinking agent such as hexamethylene diisocyanate.
• the crosslinking agent is preferably a block isocyanate crosslinking agent selected from allophanate, biuret, or adduct forms of hexamethylene diisocyanate.
• the reactivity increases, making it easier for the crosslinking reaction to proceed, and making it possible to improve the crosslinking density of the resulting coating layer.
• the density of the coated layer can be improved.
• cyclic structures such as urtodione and isocyanurate are less preferred because they have high steric hindrance as multimers, making it difficult to interact with n-hexamethylene chains derived from polycarbonate diol constituting polycarbonate polyurethane. do not have.
• a blocked isocyanate-based crosslinking agent in the coating layer forming composition in order to control the reactivity of the isocyanate.
• blocking agents include bisulfite compounds such as sodium bisulfite, 3,5-dimethylpyrazole, 3-methylpyrazole, 4-bromo-3,5-dimethylpyrazole, 4-nitro-3,5-dimethyl Pyrazole compounds such as pyrazole, phenols such as phenol and cresol, aliphatic alcohols such as methanol and ethanol, active methylene compounds such as dimethyl malonate and acetylacetone, mercaptan compounds such as butyl mercaptan and dodecyl mercaptan, acetanilide, and acetamide.
• Acid amides such as ⁇ -caprolactam, lactams such as ⁇ -valerolactam, acid imides such as succinimide and maleimide, oximes such as acetaldoxime, acetone oxime, methyl ethyl ketoxime, diphenylaniline, aniline , amine-based blocking agents such as ethyleneimine, and the like, but from the viewpoint of reactivity, blocking agents having a pyrazole-based skeleton are preferably used in this system.
• hydrophilic group into the blocked isocyanate-based crosslinking agent from the viewpoint of imparting water dispersibility to an aqueous solvent.
• hydrophilicity it is preferable to introduce an anionic group such as a carboxyl group or a sulfonic acid group, or a nonionic group such as an oxyalkyl group.
• anionic group such as a carboxyl group or a sulfonic acid group
• nonionic group such as an oxyalkyl group.
• These hydrophilic groups can be produced by reacting in advance a polyisocyanate, which is the base of the blocked isocyanate, with a compound having a hydrophilic group and a reactive group such as a hydroxyl group.
• the blocked isocyanate-based crosslinking agent is contained in an amount of 5% by mass or more and 50% by mass or less in the solid content of the total binder resin and crosslinking agent contained in the coating layer forming composition. More preferably, it is 10% by mass or more and 45% by mass or less. More preferably, it is 10% by mass or more and 40% by mass or less, and most preferably 10% by mass or more and 20% by mass or less. If it is 5% by mass or more, the strength of the coating layer is maintained and the adhesion is good under high temperature and high humidity conditions, and if it is 50% by mass or less, the flexibility of the coating layer is maintained and it can be used at room temperature. This is preferable because it maintains adhesion under high temperature and high humidity conditions.
• the content of the n-hexanediol component is preferably 5 mol% or more and 30 mol% or less, more preferably 6
• the content is mol% or more and 28 mol% or less, particularly preferably 7 mol% or more and 26 mol% or less.
• the melting point of the polycarbonate diol constituting the polycarbonate polyurethane is preferably 10°C or higher, more preferably 20°C or higher, and still more preferably 30°C or higher.
• the temperature is 10° C. or higher, the crystallinity of the polycarbonate polyurethane to be prepared is increased, the hardness and rigidity are improved, and the mechanical properties as a coating layer are improved.
• the melting point of the polycarbonate diol is preferably 10°C or higher, but preferably 150°C or lower, and preferably 100°C or lower.
• polycarbonate polyurethane may be used alone and included in the coating layer forming composition, but other types of resins may be used in combination to form the coating layer.
• polyester resin is suitable as the resin in consideration of adhesion to the base material.
• the binder resin When the total mass of the binder resin and crosslinking agent in the coating layer forming composition is 100% by mass, the binder resin preferably accounts for 50 to 95% by mass from the viewpoint of adhesion, more preferably 55 to 90% by mass. %, more preferably 60 to 90% by weight, most preferably 80 to 90% by weight. If it is 95% by mass or less, the strength of the coating layer is maintained and the adhesion is good under high temperature and high humidity, and if it is 50% by mass or more, the flexibility of the coating layer is maintained and it can be used at room temperature. This is preferable because it maintains adhesion under high temperature and high humidity conditions. All of the binder resins may be polycarbonate polyurethane, or other binder resins may be mixed.
• the polycarbonate polyurethane preferably accounts for 10% by mass or more, more preferably 20% by mass or more in the binder resin.
• a binder resin such as polyester other than polycarbonate polyurethane is included as a binder resin, it is preferably kept at 90% by mass or less, and more preferably kept at 80% by mass or less.
• binder resin other than polycarbonate polyurethane may not be used.
• the coating layer in the easily adhesive polyester film of the present invention is preferably formed from a composition containing polycarbonate polyurethane and a blocked isocyanate crosslinking agent that meet the above requirements.
• the expression "formed from this composition” is used because it is difficult to appropriately express the chemical composition of the coating layer formed by reaction curing with a crosslinking agent.
• additives such as surfactants, antioxidants, heat stabilizers, weather stabilizers, ultraviolet absorbers, organic lubricants, and pigments may be added to the extent that they do not impair the effects of the present invention.
• dyes, organic or inorganic particles, antistatic agents, nucleating agents, etc. may be added. However, it is preferable not to use substances that are unfavorable in the environment.
• the particles to be contained in the coating layer include, for example, titanium oxide, barium sulfate, calcium carbonate, calcium sulfate, silica, alumina, talc, kaolin, clay, etc., or a mixture thereof, and also other general particles.
• Inorganic particles such as calcium phosphate, mica, hectorite, zirconia, tungsten oxide, lithium fluoride, calcium fluoride, etc., and organic particles such as styrene, acrylic, melamine, benzoguanamine, silicone, etc. Examples include polymer particles.
• the average particle size of the particles in the coating layer is preferably 0.04 to 2.0 ⁇ m, more preferably 0.1 to 1.0 ⁇ m.
• the average particle size of the particles is 0.04 ⁇ m or more, it becomes easier to form unevenness on the film surface, improving handling properties such as slipperiness and winding properties of the film, and improving workability during lamination. is good and preferred.
• the average particle diameter of the particles is 2.0 ⁇ m or less because particles are less likely to fall off.
• the coating layer may not contain any particles, the content of particles is preferably 1 to 20% by weight based on the total weight of the resin and crosslinking agent.
• the thickness of the coating layer is preferably 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 workability and adhesion.
• the thickness is 50 nm or more and 150 nm or less, and even more preferably, 70 nm or more and 100 nm or less. If the thickness of the coating layer is 30 nm or more, the adhesion becomes good, which is preferable. If the thickness of the coating layer is 200 nm or less, blocking is less likely to occur, which is preferable.
• the thickness of the coating layer was determined by observing the cross section of the cut film using a transmission electron microscope (TEM), measuring the thickness of the coating layer at 10 random points, and taking the average value as the thickness of the coating layer.
• TEM transmission electron microscope
• the composition for forming a coating layer can also contain a surfactant for the purpose of improving leveling properties during coating and defoaming the coating solution.
• the surfactant may be cationic, anionic, or nonionic, but silicone, acetylene glycol, or fluorine surfactants are preferred. These surfactants are preferably included in the coating layer forming composition within a range that does not impair the effect of suppressing iris-like coloring under a three-wavelength LED light source and the adhesion.
• both the so-called in-line coating method, in which the polyester base film is coated at the same time as the film is formed, and the so-called offline coating method, in which the polyester base film is coated with a separate coater after the film is formed, can be applied.
• In-line coating method is efficient and more preferred.
• any known method can be used for coating a polyethylene terephthalate (hereinafter abbreviated as PET) film with a coating liquid.
• PET polyethylene terephthalate
• examples include reverse roll coating method, gravure coating method, kiss coating method, die coater method, roll brushing method, spray coating method, air knife coating method, wire bar coating method, pipe doctor method, impregnation coating method, curtain coating method, etc. It will be done. Coating can be performed using these methods alone or in combination.
• a method for forming a coating layer on a polyester film includes a method of applying a coating liquid containing a solvent, particles, and resin to a polyester film and drying the coating solution.
• the solvent include water or a mixture of water and an organic solvent, but water alone or a mixture of water and a water-soluble organic solvent is preferred from the viewpoint of environmental issues.
• water-soluble organic solvents examples include alcohols such as isopropyl alcohol and ethanol, ketones such as methyl ethyl ketone, ethers such as butyl cellosolve, amines such as triethanolamine, and amides such as N-methylpyrrolidone.
• alcohols such as isopropyl alcohol and ethanol
• ketones such as methyl ethyl ketone
• ethers such as butyl cellosolve
• amines such as triethanolamine
• amides such as N-methylpyrrolidone.
• the solid content concentration of the coating liquid depends on the type of binder resin and the type of solvent, it is preferably 2% by mass or more, and more preferably 4% by mass or more.
• the solid content concentration of the coating liquid is preferably 35% by mass or less, more preferably 15% by mass or less.
• the drying temperature after coating also depends on the type of binder resin, the type of solvent, the presence or absence of a crosslinking agent, the solid content concentration, etc., but is preferably 80°C or higher and preferably 250°C or lower.
• the polyester film serving as the base material of the easily adhesive polyester film of the present invention can be manufactured according to a general polyester film manufacturing method. For example, a polyester resin is melted, unoriented polyester extruded into a sheet, stretched in the longitudinal direction using a speed difference between rolls at a temperature higher than the glass transition temperature, and then stretched in the transverse direction with a tenter.
• a method of applying heat treatment is a method of applying heat treatment.
• the polyester film in the present invention may be a uniaxially stretched film or a biaxially stretched film, but when a biaxially stretched film is used as a protective film on the front of a liquid crystal panel, it can be observed from directly above the film surface. Although no rainbow-like color spots can be seen in the image, care must be taken as rainbow-like color spots may be observed when observed from an oblique direction.
• the biaxially stretched film consists of a refractive index ellipsoid that has different refractive indices in the running direction, width direction, and thickness direction, and the retardation becomes zero depending on the direction of light transmission inside the film (refractive index ellipsoid). This is because there is a direction in which the body appears to be a perfect circle. Therefore, when observing a liquid crystal display screen from a specific diagonal direction, there may be a point where the retardation becomes zero, and rainbow-like color spots will appear concentrically around that point.
• ⁇ is the angle from just above the film surface (normal direction) to the position where the rainbow-like color spots are visible, this angle ⁇ becomes larger as the birefringence within the film surface increases, and the rainbow-like color spots become larger. The spots become difficult to see. Since the angle ⁇ tends to be small in a biaxially stretched film, a uniaxially stretched film is preferable from the viewpoint that rainbow-like color spots are less visible. However, biaxially stretched films are preferable from the viewpoint of mechanical properties.
• a known hard coat layer material can be used to form the hard coat layer, and the hard coat layer may be formed by, but not limited to, drying, heat, chemical reaction, or irradiation with electron beams, radiation, or ultraviolet rays.
• Polymerizable and/or reactive resin compounds can be used.
• curable resins include melamine-based, acrylic-based, silicone-based, and polyvinyl alcohol-based curable resins, but photocurable acrylic curable resins are suitable for obtaining high surface hardness or optical design. Resins are preferred.
• acrylic curable resin polyfunctional (meth)acrylate monomers and acrylate oligomers can be used.
• acrylate oligomers include polyester acrylate, epoxy acrylate, urethane acrylate, and polyester acrylate.
• examples include ether acrylate, polybutadiene acrylate, and silicone acrylate.
• a coating composition for forming the optical functional layer can be obtained by mixing a reactive diluent, a photopolymerization initiator, a sensitizer, etc. with these acrylic curable resins.
• the above hard coat layer may have an anti-glare function to scatter 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 preferably 0 to 50%, more preferably 0 to 40%, particularly preferably 0 to 30%.
• 0% is ideal, and it may be 0.2% or more, or 0.5% or more.
• the hard coat layer and other functional layers have a refractive index. It is preferable to adjust the reflectance to ideally achieve a reflectance of 0 to 1.0%, more preferably 0 to 0.8%, particularly preferably 0 to 0.5%. Of course, 0% is ideal, and it may be 0.05% or more, or 0.1% or more.
• the easily adhesive polyester film of the present invention can also be used as a polarizer protective film.
• a polarizing plate is formed by placing polarizer protective films on both sides of a polarizer, but the polarizer protective film on at least one side of the polarizer may be the easily adhesive polyester film for polarizer protection.
• the other polarizer protective film may be the easily adhesive polyester film of the present invention, or it is preferable to use a film without birefringence, such as a triacetyl cellulose film, an acrylic film, or a norbornene film. .
• the polarizer examples include a polyvinyl alcohol 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 adhesiveness, it is preferable to attach the polarizer via an adhesive. In this case, it is preferable that the easily bonding layer of the present invention is disposed on the polarizer surface or the adhesive layer surface.
• a preferred polarizer for adhering the polyester film of the present invention is, for example, a polyvinyl alcohol film dyed and adsorbed with iodine or a dichroic material, uniaxially stretched in a boric acid aqueous solution, and then stretched while maintaining the stretched state.
• Examples include polarizers obtained by washing and drying. The stretching ratio of uniaxial stretching is usually about 4 to 8 times.
• Polyvinyl alcohol is suitable as the polyvinyl alcohol film, and examples include "Kuraray Vinylon” [manufactured by Kuraray Co., Ltd.], "Tosero Vinylon” [manufactured by Tohcello Co., Ltd.], and "Higo Vinylon” [manufactured by Nippon Gosei Kagaku Co., Ltd.]. You can use commercially available products such as Examples of dichroic materials include iodine, disazo compounds, and polymethine dyes.
• the adhesive applied to the polarizer is preferably water-based, that is, one in which the adhesive component is dissolved or dispersed in water.
• the adhesive layer is preferably 5 ⁇ m or less, more preferably 3 ⁇ m or less, and even more preferably 1 ⁇ m or less.
• polyvinyl alcohol resin As the main component of the adhesive, in addition to partially saponified polyvinyl alcohol, fully saponified polyvinyl alcohol, carboxyl group-modified polyvinyl alcohol, acetoacetyl group-modified polyvinyl alcohol, methylol group-modified polyvinyl alcohol, amino group-modified polyvinyl alcohol, etc. Modified polyvinyl alcohol resins such as polyvinyl alcohol may also be used.
• the concentration of the polyvinyl alcohol resin in the adhesive is preferably 1 to 10% by mass, more preferably 2 to 7% by mass.
• the thickness of the adhesive layer after curing can be arbitrarily set by designing the characteristics of the polarizing plate, but a smaller thickness is preferable from the viewpoint of reducing adhesive material costs. Generally, it is 0.01 to 20 ⁇ m, preferably 0.1 to 10 ⁇ m, and more preferably 0.5 to 5 ⁇ m. It is preferable that the thickness of the adhesive layer is 0.01 ⁇ m or more because it is difficult for air bubbles to be mixed into the adhesive layer and has good adhesion and durability. It is preferable that the adhesive layer has a thickness of 20 ⁇ m or less because the reaction rate of the adhesive is sufficient and the heat and humidity resistance of the polarizing plate is good.
• the photocurable adhesive preferably contains an epoxy compound containing no aromatic ring as a main component, and contains a photocationic curing component (I) and a photocationic polymerization initiator (II).
• the photocurable adhesive has an epoxy compound containing no aromatic ring as a main component.
• Epoxy compounds that do not contain aromatic rings are epoxy compounds other than aromatic epoxy compounds, and are hereinafter referred to as aliphatic epoxy compounds.
• An "epoxy compound” is a compound having at least one epoxy group in its molecule.
• the aliphatic epoxy compound that is the main component may contain two or more types of epoxy compounds.
• "Main component” means that the content of the aliphatic epoxy compound is 50% by mass or more based on 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, still more preferably 80% by mass or more, 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 that does not contain an alicyclic ring and is composed only of a linear hydrocarbon structure and/or a branched hydrocarbon structure. It may also be an epoxy compound.
• aliphatic epoxy compounds may contain unsaturated bonds such as double bonds, or may contain heteroatoms other than oxygen atoms (oxygen atoms, nitrogen atoms, sulfur atoms, halogen atoms, etc.) contained in the epoxy group. It may further contain.
• the photocationic curable component (I) is a component that provides adhesive strength through polymerization and curing by irradiation with active energy rays, and preferably contains the first epoxy compound (I-1) described in detail below.
• the photocationic curable component (I) preferably further contains a second epoxy compound (I-2) or a third epoxy compound (I-3), which will be detailed below, together with the first epoxy compound (I-1). More preferably, at least a second epoxy compound (I-2) is further contained together with the first epoxy compound (I-1).
• the photocationic curable component (I) more preferably further contains a second epoxy compound (I-2) and a third epoxy compound (I-3) together with the first epoxy compound (I-1).
• the photocurable adhesive preferably contains a photocationic polymerization initiator (II).
• the adhesive layer can be formed by curing the photocationic curable component through cationic polymerization by irradiation with active energy rays.
• the photocationic polymerization initiator (II) generates cationic species or Lewis acids upon irradiation with active energy rays such as visible light, ultraviolet rays, X-rays, and electron beams, and initiates the polymerization reaction of the photocationic curable component. It is something. Since the photocationic polymerization initiator (II) acts catalytically with light, it has excellent storage stability and workability even when mixed with the photocationic curable component.
• Examples of compounds that generate cationic species or Lewis acids upon irradiation with active energy rays that can be used as photocationic polymerization initiators (II) include aromatic diazonium salts; onium salts such as aromatic iodonium salts and aromatic sulfonium salts; Examples include iron-arene complexes.
• aromatic diazonium salts examples include benzenediazonium hexafluoroantimonate, benzenediazonium hexafluorophosphate, and benzenediazonium hexafluoroborate.
• aromatic iodonium salt examples include diphenyliodonium tetrakis(pentafluorophenyl)borate, diphenyliodonium hexafluorophosphate, diphenyliodonium hexafluoroantimonate, and di(4-nonylphenyl)iodonium hexafluorophosphate.
• aromatic sulfonium salts include triphenylsulfonium hexafluorophosphate, triphenylsulfonium tetrakis(pentafluorophenyl)borate, 4,4-bis[diphenylsulfonio]diphenylsulfide bishexafluorophosphate, and 4,4-bis[diphenylsulfonio]diphenylsulfide bishexafluorophosphate.
• iron-arene complexes examples include xylene-cyclopentadienyl iron(II) hexafluoroantimonate, cumene-cyclopentadienyl iron(II) hexafluorophosphate, xylene-cyclopentadienyl iron(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 absorbing properties even in the wavelength region around 300 nm, have excellent curability, and can provide an adhesive layer with good mechanical strength and adhesive strength. It will be done.
• the content of the photocationic polymerization initiator (II) is preferably 1 to 10 parts by weight, more preferably 2 to 6 parts by weight, based on 100 parts by weight of the entire photocationic curable component.
• the photocationic curable component can be sufficiently cured, and the resulting polarizing plate can be given high mechanical strength and adhesive strength.
• the content of II) is preferably 10 parts by mass or less based on 100 parts by mass of the photocationically curable component.
• the laminated polyester film of the present invention in which a functional layer is provided on the coating layer of the easily adhesive polyester film, is mainly used in a wide range of optical films, including prism lens sheets, AR (anti-reflection) films, hard coat films, and diffusion plates.
• optical films including prism lens sheets, AR (anti-reflection) films, hard coat films, and diffusion plates.
• base films for optical components such as LCDs, flat TVs, and CRTs, such as anti-crushing films, near-infrared absorbing filters that are used as front panels for plasma displays, and transparent conductive films for touch panels and electroluminescence devices. It can be used for.
• the acrylic resin that is cured by electron beam or ultraviolet light for forming the functional layer is one having an acrylate or methacrylate functional group, such as relatively low molecular weight polyester resin, polyether resin,
• an acrylate or methacrylate functional group such as relatively low molecular weight polyester resin, polyether resin
• acrylic resins epoxy resins, urethane resins, alkyd resins, spiroacetal resins, polybutadiene resins, polythiol polyene resins, polyhydric alcohols, etc.
• oligomers or prepolymers such as (meth)acrylates of polyfunctional compounds and ethyl as a reactive diluent.
• Monofunctional monomers such as (meth)acrylate, ethylhexyl (meth)acrylate, and polyfunctional monomers such as trimethylolpropane tri(meth)acrylate, hexanediol (meth)acrylate, tripropylene glycol di(meth)acrylate, diethylene glycol di( Those containing meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentylglycol di(meth)acrylate, etc. can be used.
• photopolymerization initiators such as acetophenones, benzophenones, Michler's benzoyl benzoate, ⁇ -amyloxime ester, tetramethylthiraum monosulfide, and thioxanthone are added to the resin. It is possible to use a mixture of n-butylamine, triethylamine, tri-n-butylphosphine, etc. as a photosensitizer.
• the silicone (siloxane) thermosetting resin can be produced by hydrolysis and condensation reaction of organosilane compounds alone or in combination of two or more in the presence of an acid or base catalyst.
• organosilane compounds alone or in combination of two or more in the presence of an acid or base catalyst.
• the electron beam or ultraviolet curable acrylic resin, oligomer, monomer, or siloxane thermosetting resin it is preferable to apply to the coated layer surface of the easily adhesive polyester film.
• coating layers are provided on both sides, apply to at least one coating layer surface.
• the coating layer is formed by applying the coating liquid to the above-mentioned film, drying it if necessary, and then curing the coating layer by irradiating with electron beams or ultraviolet rays and heating according to the curing conditions of the coating liquid. , forming a functional layer.
• the thickness of the functional layer is preferably 1 to 15 ⁇ m. It is preferable that the thickness of the layer is 1 ⁇ m or more, since the functional layer can efficiently exhibit its effects on chemical resistance, scratch resistance, stain resistance, etc. On the other hand, it is preferable that the thickness is 15 ⁇ m or less because the flexibility of the functional layer is maintained and there is no risk of cracking or the like.
• the scratch resistance it is preferable that when the coated surface is abraded with a black mount, the scratches are not visually noticeable. If the scratches are not noticeable in the above evaluation, they are less likely to be scratched when passing through the guide rolls, which is preferable from the viewpoint of handling properties and the like.
• the easily adhesive polyester film and laminated polyester film of the present invention are mainly used for optical applications, it is preferable that they have high transparency.
• the lower limit of haze is ideally 0%, and the closer it is to 0%, the more preferable it is.
• the upper limit of haze is preferably 2%, and 2% or less is preferable because light transmittance is good and a clear image can be obtained in a liquid crystal display device.
• the haze of a polyester film can be measured, for example, according to the method described below.
• the coating layer of the easily adhesive polyester film use a coating liquid for forming a functional layer having the composition as described above.
• a coating liquid for forming a functional layer having the composition as described above For example, in the case of a hard coat layer, apply it using an appropriate wire bar or the like. The solvent can be removed by drying for 1 minute at °C.
• the film coated with the functional layer is irradiated with ultraviolet rays of 300 mJ/cm 2 using, for example, a high-pressure mercury lamp, to obtain a laminated polyester film having the functional layer.
• the adhesion between the easily adhesive coating layer and the functional layer is obtained by evaluation using the measurement method described below.
• the adhesion (X) after film formation is preferably 95% or more. More preferably it is 98% or more, and still more preferably 100%. When it is 95% or more, it can be said that the adhesion between the coating layer and the functional layer is sufficiently maintained.
• "after film formation” refers to a film that has been continuously stored in a temperature environment of 40° C. or lower, and within 6 months after film formation.
• the adhesion (Y) between the easily adhesive coating layer and the functional layer under high temperature and high humidity conditions of 80° C. and 95% RH, evaluated according to the method described below, is the same as above, and the adhesion is 95% or more. It is preferable. More preferably it is 98% or more, and still more preferably 100%. When it is 95% or more, the adhesion between the easily adhesive coating layer and the functional layer under high temperature and high humidity conditions is satisfied, and the passability in the post-processing process is also satisfied.
• the easily adhesive polyester film of the present invention is a film with high adhesion reliability (a property that maintains adhesion even after being left in a high temperature and high humidity environment), and even after being exposed to a high temperature and high humidity environment. , high adhesion appears as an effect. Therefore, the above-mentioned X (%) and Y (%) satisfy the following formula (1).
• X-Y (%) ⁇ 5...Formula (1) It is preferable that the value of formula (1) is 5% or less. More preferably it is 3% or less, and even more preferably 0%. When it is 5% or less, it can be judged that there is no significant difference between the adhesion after film formation and the adhesion after moist heat treatment, and it can be judged that both are sufficiently adhered.
• Average particle size [Measurement method using a scanning electron microscope]
• the average particle diameter of the above particles can be measured by the following method. Particles are photographed using a scanning electron microscope (SEM), and the maximum diameter of 300 to 500 particles (between the two furthest points) is distance), and the average value is taken as the average particle size.
• the average particle size of particles present in the coating layer in the present invention can be measured by the measuring method.
• the average particle diameter of particles can also be determined by dynamic light scattering when producing particles or films.
• the sol was diluted with a dispersion medium, measured using a submicron particle analyzer N4 PLUS (manufactured by Beckman Coulter) using the parameters of the dispersion medium, and calculated using the cumulant method to obtain an average particle diameter.
• the average particle diameter of the particles in the sol is observed, and when particles aggregate with each other, the average particle diameter of those aggregated particles is observed.
• Adhesion of functional layer (1) A hard coat layer was formed on the easily adhesive coating layer of the polyester film obtained in the example. The adhesion between the hard coat layer and the base film was determined in accordance with the description in 8.5.1 of JIS-K5400-1990 using the easily adhesive polyester film on which the hard coat layer was formed.
• the coating liquid used to form the hard coat layer was prepared as follows.
• a hard coat layer having the above composition was formed on the easily adhesive coating layer.
• the coating solution was applied using a #14 wire bar and dried at 70° C. for 1 minute to remove the solvent.
• the film coated with the hard coat layer was irradiated with ultraviolet rays of 300 mJ/cm 2 using a high-pressure mercury lamp to obtain a hard coat film having a hard coat layer with a thickness of 7 ⁇ m.
• a specific method for measuring adhesion is as follows. Using a cutter guide with a gap interval of 2 mm, 100 square cuts are made on the surface of the hard coat layer, penetrating the hard coat layer and reaching the base film. Next, a cellophane adhesive tape (manufactured by Nichiban, No. 405; 24 mm width) is pasted on the square cut surface and rubbed with an eraser to ensure complete adhesion. Thereafter, the cellophane adhesive tape was vertically peeled off from the hard coat layer surface of the easily adhesive polyester film on which the hard coat layer was formed, and the squares were peeled off from the hard coat layer surface of the easily adhesive polyester film on which the hard coat layer was formed.
• Adhesion (%) ⁇ 1-(number of peeled squares/100) ⁇ 100 (4) Adhesion of functional layer (2) A photocurable adhesive layer was formed on the easily adhesive coating layer of the easily adhesive polyester film obtained in the example. The adhesion between the photocurable adhesive layer and the base film was determined in accordance with the description in 8.5.1 of JIS-K5400-1990 using the easily adhesive polyester film on which the photocurable adhesive layer was formed.
• the coating liquid used for forming the photocurable adhesive layer was prepared as follows. (Preparation of coating liquid N for forming photocurable adhesive layer) 3,4-Epoxycyclohexylmethyl-3,4'-epoxycyclohexanecarboxylate 23.81% by mass (Celloxide2021P manufactured by Daicel) 1,4-cyclohexanedimethanol diglycidyl ether 23.81% by mass (EX-216L manufactured by Nagase ChemteX) 3-ethyl-3-[(3-ethyloxetan-3-yl)methoxymethyl]oxetane 47.62% by mass (Aronoxetane DOX221 manufactured by Toagosei) Cation initiator 4.76% by mass (CPI-100P manufactured by Sanapro)
• the aromatic component in the total resin in the prepared coating liquid N for forming a photocurable adhesive layer was 13.3% in molar ratio.
• the easily adhesive polyester film produced in the examples described below was stored at a temperature and humidity of 20° C. and 65% RH, and 12 hours after film formation, a photocurable adhesive having the above composition was applied on the easily adhesive coating layer.
• a coating solution for forming a coating layer was applied using a #3 wire bar.
• the film coated with the photocurable adhesive layer was irradiated with ultraviolet rays of 500 mJ/cm 2 using a high-pressure mercury lamp to obtain a laminated film for use as a polarizer protective film having a photocurable adhesive layer with a thickness of 5 ⁇ m. .
• a specific method for measuring adhesion is as follows. Using a cutter guide with a gap interval of 2 mm, 100 square cuts are made on the surface of the photocurable adhesive layer, penetrating the photocurable adhesive layer and reaching the base film. Next, a cellophane adhesive tape (manufactured by Nichiban, No. 405; 24 mm width) is pasted on the square cut surface and rubbed with an eraser to ensure complete adhesion. Thereafter, the cellophane adhesive tape was vertically peeled off from the photocurable adhesive layer surface of the easily adhesive polyester film on which the photocurable adhesive layer was formed, and the easily adhesive polyester film on which the photocurable adhesive layer was formed.
• Adhesion (%) ⁇ 1-(number of peeled squares/100) ⁇ 100 (5)
• Humid and heat resistance (adhesion after being left at 80°C and 90% RH)
• the obtained easily adhesive polyester film was left for 24 hours in a high-temperature, high-humidity tank at 80° C. and 90% RH, and then at room temperature (20° C., 65% RH) for 12 hours. Thereafter, a functional layer was formed in the same manner as described above, and its adhesion to the base film was determined.
• Synthesis of polyurethane resin (PU-1) 29.4 parts by mass of dicyclohexylmethane-4,4'-diisocyanate was placed in a four-necked flask equipped with a stirrer, a Dimroth condenser, a nitrogen introduction tube, a silica gel drying tube, and a thermometer.
• aqueous dispersion (PU-1WD) of polyurethane resin (PU-1) A predetermined amount of water was added to a reaction vessel equipped with a homodisper capable of high-speed stirring, the temperature was adjusted to 25°C, and the mixture was stirred at 2000 min -1. While stirring and mixing, the aforementioned polyurethane resin (PU-1) solution was gradually added and dispersed in water. Thereafter, the solvent ethyl methyl ketone was removed under reduced pressure. By adjusting the concentration with water, an aqueous dispersion (PU-1WD) of a polyurethane resin (PU-1) with a solid content of 35.0% by mass was prepared.
• Synthesis of polyurethane resin (PU-2) 29.4 parts by mass of dicyclohexylmethane-4,4'-diisocyanate was placed in a four-necked flask equipped with a stirrer, a Dimroth condenser, a nitrogen inlet tube, a silica gel drying tube, and a thermometer.
• aqueous dispersion (PU-2WD) of polyurethane resin (PU-2) A predetermined amount of water was added to a reaction vessel equipped with a homodisper capable of high-speed stirring, the temperature was adjusted to 25°C, and the mixture was stirred at 2000 min -1. While stirring and mixing, the aforementioned polyurethane resin (PU-2) solution was gradually added and dispersed in water. Thereafter, the solvent ethyl methyl ketone was removed under reduced pressure. By adjusting the concentration with water, an aqueous dispersion (PU-2WD) of polyurethane resin (PU-2) with a solid content of 35.0% by mass was prepared.
• Synthesis of polyurethane resin (PU-3) 29.4 parts by mass of dicyclohexylmethane-4,4'-diisocyanate, 31.8 parts by mass of polycarbonate diol mainly made of 1,4-butanediol having a number average molecular weight of 1000 and 31.8 parts by mass of polycarbonate diol mainly made of 1,6-hexanediol having a number average molecular weight of 1000, 7 parts by mass of dimethylolpropionic acid, and 200 parts by mass of ethyl methyl ketone as a solvent were added to a four-neck flask equipped with a stirrer, a Dimroth condenser, a nitrogen inlet tube, a silica gel drying tube, and a thermometer, and the mixture was stirred for 3 hours at 75°C under a nitrogen atmosphere, and the infrared spectrum of the reaction solution was measured to confirm the disappearance of the isocyanate group in the reaction solution.
• aqueous dispersion (PU-3WD) of polyurethane resin (PU-3) Add a predetermined amount of water to a reaction vessel equipped with a homodisper capable of high-speed stirring, adjust the temperature to 25°C, and stir at 2000 min -1. While stirring and mixing, the aforementioned polyurethane resin (PU-3) solution was gradually added and dispersed in water. Thereafter, the solvent ethyl methyl ketone was removed under reduced pressure. By adjusting the concentration with water, an aqueous dispersion (PU-3WD) of a polyurethane resin (PU-3) with a solid content of 35.0% by mass was prepared.
• Synthesis of polyurethane resin (PU-4) 29.4 parts by mass of dicyclohexylmethane-4,4'-diisocyanate was placed in a four-necked flask equipped with a stirrer, a Dimroth condenser, a nitrogen inlet tube, a silica gel drying tube, and a thermometer.
• aqueous dispersion (PU-4WD) of polyurethane resin (PU-4) A predetermined amount of water was added to a reaction vessel equipped with a homodisper capable of high-speed stirring, the temperature was adjusted to 25°C, and the mixture was stirred at 2000 min -1. While stirring and mixing, the aforementioned polyurethane resin (PU-4) solution was gradually added and dispersed in water. Thereafter, the solvent ethyl methyl ketone was removed under reduced pressure. By adjusting the concentration with water, an aqueous dispersion (PU-4WD) of polyurethane resin (PU-4) with a solid content of 35.0% by mass was prepared.
• polyester resins In a stainless steel autoclave equipped with a stirrer, a thermometer, and a partial reflux condenser, 342.0 parts by mass of dimethyl 2,6-naphthalene dicarboxylate, 35.0 parts by mass of dimethyl terephthalate, and dimethyl 35.5 parts by mass of -5-sodium sulfoisophthalate, 198.6 parts by mass of ethylene glycol, 118.2 parts by mass of 1,6-hexanediol, and 0.4 parts by mass of tetra n-butyl titanate were charged, and the mixture was heated from 160°C. The transesterification reaction was carried out at a temperature of 220° C. for 4 hours.
• polyester aqueous dispersion 30 parts by mass of copolyester resin (PEs) and 15 parts by mass of ethylene glycol-n-butyl ether were placed in a reactor equipped with a stirrer, a thermometer and a reflux device, and 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) aqueous dispersion (PEsWD) with a solid content of 25.0% by mass.
• PEs copolyester resin
• PEsWD ethylene glycol-n-butyl ether
• aqueous dispersion (C-1WD) of blocked isocyanate-based crosslinking agent (C-1) A polyisocyanate compound having a biuret structure made from hexamethylene diisocyanate as a raw material ( Asahi Kasei Chemicals, Duranate 24A-100 (NCO concentration 23.1%) 125.2 parts by mass, 50.0 parts by mass of dipropylene glycol dimethyl ether and 68.8 parts by mass of 3,5-dimethylpyrazole were added under a nitrogen atmosphere. , and maintained at 70° C. for 2 hours while stirring. Thereafter, the infrared spectrum of the reaction solution was measured, and it was confirmed that the absorption of isocyanate groups had disappeared.
• Asahi Kasei Chemicals, Duranate 24A-100 (NCO concentration 23.1%) 125.2 parts by mass, 50.0 parts by mass of dipropylene glycol dimethyl ether and 68.8 parts by mass of 3,5-dimethylpyrazole were added under a nitrogen atmosphere.
• aqueous dispersion C-2WD
• blocked isocyanate crosslinking agent C-2
• a polyisocyanate compound having an adduct structure made from hexamethylene diisocyanate as a raw material Asahi Kasei Chemicals, Duranate P301-75E, dissolved in ethyl acetate, solid concentration 75.0%, NCO concentration 12.5%
• 125.2 parts by mass 50.0 parts by mass of dipropylene glycol dimethyl ether and 3,5-dimethyl 37.2 parts by mass of pyrazole was added, and the mixture was maintained at 70° C. for 2 hours with stirring under a nitrogen atmosphere.
• aqueous dispersion (C-3WD) of blocked isocyanate crosslinking agent (C-3) A polyisocyanate compound having an allophanate structure made from hexamethylene diisocyanate as a raw material ( Asahi Kasei Chemicals, Duranate A201H, NCO concentration 17.2%) 125.2 parts by mass, 50.0 parts by mass of dipropylene glycol dimethyl ether and 51.2 parts by mass of 3,5-dimethylpyrazole were added, and under a nitrogen atmosphere, The mixture was maintained at °C for 2 hours with stirring. Thereafter, the infrared spectrum of the reaction solution was measured, and it was confirmed that the absorption of isocyanate groups had disappeared.
• solvent phenol/tetrachloroethane
• the above coating solution was applied to one side of the PET film by a roll coating method, and then dried at 80° C., and the coating amount after drying after final stretching was adjusted to 0.12 g/m 2 . Subsequently, the film was stretched 4.0 times in the width direction at 150°C using a tenter, heated at 230°C with the length of the film fixed in the width direction, and further subjected to relaxation treatment in the width direction at 230°C. An easily adhesive polyester film having a thickness of 50 ⁇ m was obtained.
• the thickness of the easily adhesive coating layer of the obtained easily adhesive polyester film was 82 nm, and the film haze was 0.54%.
• the above-mentioned coating liquid L for forming a hard coat layer was used on the easily-adhesive coating layer of the easily-adhesive polyester film, and a laminated polyester film was obtained according to the above-mentioned forming method.
• the adhesion X was 100%.
• the obtained easily adhesive polyester film was left in a high-temperature, high-humidity tank at 80°C and 90RH% for 24 hours, and then at room temperature for 12 hours. Thereafter, a hard coat layer was formed on the easily adhesive coating layer of the treated easily adhesive polyester film using coating liquid L for forming a hard coat layer to obtain a laminated polyester film.
• the adhesion Y was 100%.
• the above roll was left in an environment of temperature: 0° C. to 30° C. and humidity: 10% RH to 80% RH for 6 months, and a sample was taken from the product roll, and the adhesion was evaluated in the same manner as above.
• the adhesion evaluation results of the actually stored rolls were designated as Z and are listed in Table 1. Regarding the adhesion reliability based on this result, those that were able to ensure an adhesion of 100% or more are ⁇ , those that were able to ensure an adhesion of 95% or more and 100% or less are ⁇ , and those that were able to ensure an adhesion of 95% or more. Those that were able to ensure adhesion of 95% or more were marked as ⁇ , and those that could not ensure adhesion of 95% or more were marked as ⁇ . The evaluation results of adhesion reliability are listed in the adhesion reliability column of Table 1. If adhesion of 95% or more was ensured, it can be confirmed that adhesion reliability was ensured.
• the adhesion (Z) was 95%, and as a result, the adhesion reliability was 0, and it was judged that the adhesion reliability was secured.
• Example 2 An easily adhesive polyester film was obtained in the same manner as in Example 1, except that the resin used was changed to PU-4WD and a coating liquid prepared as follows was used.
• Example 3 An easily adhesive polyester film was obtained in the same manner as in Example 1, except that the thickness of the coating liquid was changed to the thickness listed in Table 1.
• the obtained easily adhesive polyester film was evaluated in the same manner as in Example 1, and then in the same manner as in Example 1, a laminated polyester film provided with a functional layer was obtained. Various evaluation results are shown in Table 1.
• Example 5 An easily adhesive polyester film was obtained in the same manner as in Example 1, except that a coating liquid having the following composition was prepared.
• the obtained easily adhesive polyester film was evaluated in the same manner as in Example 1, and then in the same manner as in Example 1, a laminated polyester film provided with a functional layer was obtained. Various evaluation results are shown in Table 1.
• Example 6 (Examples 6, 7, 8, 9) Similarly to Example 2, an easily adhesive polyester film was obtained in the same manner as in Example 1, except that the resin used was changed to the resin listed in Table 1.
• the obtained easily adhesive polyester film was evaluated in the same manner as in Example 1, and then in the same manner as in Example 1, a laminated polyester film provided with a functional layer was obtained. Various evaluation results are shown in Table 1.
• Example 10 An easily adhesive polyester film was obtained in the same manner as in Example 1, except that the crosslinking agent used was changed to C-2WD and a coating solution prepared as follows was used.
• Example 11 Similarly to Example 10, an easily adhesive polyester film was obtained in the same manner as in Example 1, except that the crosslinking agent used was changed to the one listed in Table 1.
• the obtained easily adhesive polyester film was evaluated in the same manner as in Example 1, and then in the same manner as in Example 1, a laminated polyester film provided with a functional layer was obtained. Various evaluation results are shown in Table 1.
• Example 12 Similarly to Example 2, an easily adhesive polyester film was obtained in the same manner as in Example 1, except that the resin used was changed to the resin listed in Table 1.
• the obtained easily adhesive polyester film was evaluated in the same manner as in Example 1, and then in the same manner as in Example 1, a laminated polyester film provided with a functional layer was obtained. Various evaluation results are shown in Table 1.
• Example 13 and 14 Evaluation was performed in the same manner as in Example 1, except that the functional layer shown in Table 1 was added to the easily adhesive polyester film produced in the same manner as in Example 2. Various evaluation results are as shown in Table 1.
• the obtained easily adhesive polyester film was evaluated in the same manner as in Example 1, and then in the same manner as in Example 1, a laminated polyester film provided with a functional layer was obtained. Various evaluation results are shown in Table 1.
• the present invention it is possible to provide an easily adhesive polyester film that ensures adhesion reliability after being left in a high temperature and high humidity environment for a long period of time, making it easier to apply it to optical applications and the like.

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• 2023
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