JP2011136551A - Easily adhesive polyester film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an easily adhesive polyester film which is excellent in adhesion to an optical functional layer at a high temperature and high humidity. <P>SOLUTION: The easily adhesive polyester film has a coating layer at least at one side of a polyester film. The coating layer contains a urethane resin containing polycarbonate polyol as a constituent and a carbodiimide compound as a main component. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an easily adhesive polyester film excellent in adhesion and heat and moisture resistance. Specifically, it is suitable as a base material for functional films such as hard coat films, antireflection films, light diffusion sheets, prismatic lens sheets, near-infrared shielding films, transparent conductive films, and antiglare films, which are mainly used for displays and the like. The present invention relates to an easily adhesive polyester film.

  In general, a transparent thermoplastic resin made of polyethylene terephthalate (PET), acrylic, polycarbonate (PC), triacetyl cellulose (TAC), polyolefin or the like is used as a base material for a functional film used as a liquid crystal display (LCD) member. A film is used.

  When using the thermoplastic resin film as a base material for various optical functional films, functional layers corresponding to various applications are laminated. For example, in a liquid crystal display (LCD), a protective film (hard coat layer) that prevents scratches on the surface, an antireflection layer (AR layer) that prevents reflection of external light, and a prism layer that is used to collect and diffuse light And a functional layer such as a light diffusion layer for improving luminance. Among such substrates, particularly polyester films are widely used as substrates for various functional films because they are excellent in transparency, dimensional stability and chemical resistance and are relatively inexpensive.

  In general, in the case of a biaxially oriented thermoplastic film such as a biaxially oriented polyester film or a biaxially oriented polyamide film, the film surface is highly crystallized, so it has good adhesion to various paints, adhesives, inks, etc. There is a disadvantage of being scarce. For this reason, methods for imparting easy adhesion to the biaxially oriented polyester film surface by various methods have been proposed.

  For example, a method of providing easy adhesion to a base film by providing a coating layer mainly composed of various resins such as polyester, acrylic, polyurethane, and acrylic graft polyester on the surface of the base polyester film is generally used. Known. Among these coating methods, the polyester film before the completion of crystal orientation is coated on the base film with an aqueous coating solution containing the resin solution or a dispersion in which the resin is dispersed in a dispersion medium, and after drying, Stretch at least uniaxially, then heat treatment to complete the orientation of the polyester film (so-called in-line coating method), after the production of the polyester film, after applying a water-based or solvent-based coating liquid to the film, A drying method (so-called off-line coating method) is industrially implemented.

  A display such as an LCD or PDP, or a portable device using a hard coat film as a member is used in various environments regardless of indoors or outdoors. In particular, portable devices may require moisture and heat resistance that can withstand a bathroom, a hot and humid area, and the like. The optical functional film used for such applications is required to have high adhesion such that delamination does not occur even under high temperature and high humidity. Therefore, in the following patent document, an easy-adhesive polyester film imparted with moisture and heat resistance is disclosed by adding a crosslinking agent to the coating solution and forming a crosslinked structure in the coating layer resin when forming the coating layer by the in-line coating method. Yes.

JP 2000-141574 A Japanese Patent No. 3900191 JP 2007-253512 A

  Longer life expectancy is expected for home appliances with a display to reduce the global environmental impact. Therefore, it was considered that the optical functional film used as a member also needs to maintain adhesiveness for a long time even under high temperature and high humidity. However, the easy-adhesion film as disclosed in the above-mentioned patent document shows good adhesion at first, but a decrease in adhesion strength is inevitable in long-term use under high temperature and high humidity. . Due to such a decrease in adhesion, there is a problem that the initial performance is not maintained for a long time.

  In view of the above problems, the present invention provides an easy-adhesive polyester film that hardly causes a decrease in adhesion under high temperature and high humidity, which has been conventionally considered to be unavoidable.

  In addition, the adhesiveness under high temperature and high humidity referred to in the present invention is a layer of a photocurable acrylic layer, placed in an environment of 80 ° C., 95% RH, 48 hours, and using a cutter guide with a gap interval of 2 mm, Apply 100 cell-shaped cuts that penetrate the photocurable acrylic layer to the base film on the surface of the photocurable acrylic layer, and then apply cellophane adhesive tape to the cell-shaped cut surface and rub it with an eraser to complete Means the adhesiveness when the same part is peeled off 5 times vigorously, and is adhesiveness according to stricter criteria than the evaluation method described in JIS K5600-5-6, which is generally used. Therefore, it is a problem that the adhesiveness under such high temperature and high humidity shows the adhesiveness equal to or higher than the initial adhesiveness.

  As a result of intensive studies to solve the above problems, the inventor of the present invention improves adhesion under high temperature and high humidity by using a coating layer containing a urethane resin having a polycarbonate polyol as a constituent component and a carbodiimide compound. And the present invention has been achieved.

The above-described problem can be achieved by the following solution means.
(1) An easily adhesive polyester film having a coating layer on at least one surface of a polyester film, wherein the coating layer is mainly composed of a urethane resin containing a polycarbonate polyol as a constituent component and a carbodiimide compound. Polyester film.
(2) The said easily adhesive polyester film in which the said urethane resin has a polyoxyalkylene group.
(3) The said easily adhesive polyester film whose said carbodiimide compound is water-soluble and whose haze is 2.5% or less.
(4) At least one functional layer selected from a hard coat layer, a light diffusion layer, a prismatic lens layer, an electromagnetic wave absorption layer, a near-infrared shielding layer, and a transparent conductive layer is formed on the coating layer of the easily adhesive polyester film. A laminated polyester film obtained by laminating layers.

  The easily-adhesive polyester film of the present invention is excellent in adhesion (humidity heat resistance) with the optical functional layer under high temperature and high humidity. Therefore, as a preferred embodiment, the adhesion at the high temperature and high humidity treatment is equal to or improved from the initial adhesion. As a preferred embodiment of the present invention, when the easily adhesive polyester film of the present invention is used as a substrate for a lens sheet, the adhesion with the lens layer under high temperature and high humidity is good.

(Polyester film)
The polyester resin constituting the polyester film used as the base material in the present invention includes polyethylene terephthalate, polybutylene terephthalate, polyethylene-2,6-naphthalate, polymethylene terephthalate, and copolymerization components such as diethylene glycol, neopentyl glycol, poly Polyester resins obtained by copolymerizing diol components such as alkylene glycol, dicarboxylic acid components such as adipic acid, sebacic acid, phthalic acid, isophthalic acid, and 2,6-naphthalenedicarboxylic acid can be used.

  The polyester resin suitably used in the present invention mainly contains at least one of polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate as a constituent component. Among these polyester resins, polyethylene terephthalate is most preferable from the balance between physical properties and cost. Moreover, these polyester films can improve chemical resistance, heat resistance, mechanical strength, etc. by biaxially stretching.

  The biaxially stretched polyester film may be a single layer or a multilayer. Moreover, as long as it exists in the range with the effect of this invention, each of these layers can contain various additives in a polyester resin as needed. Examples of the additive include an antioxidant, a light resistance agent, an antigelling agent, an organic wetting agent, an antistatic agent, an ultraviolet absorber, and a surfactant.

  In addition, in order to improve handling properties such as slipperiness, rollability and blocking resistance of the film, and wear characteristics such as wear resistance and scratch resistance, inert particles may be included in the polyester film. However, when the film of the present invention is used as a base film for an optical member, it is required to have excellent handling properties while maintaining high transparency. Specifically, when used as a substrate film for an optical member, the total light transmittance of the easily adhesive polyester film is preferably 85% or more, more preferably 87% or more, and even more preferably 88% or more. 89% or more is more preferable, and 90% or more is particularly preferable.

  For high definition, the content of inert particles in the base film is preferably as small as possible. Therefore, it is a preferred embodiment that a multilayer structure in which particles are contained only in the surface layer of the film is used, or that the particles are substantially not contained in the film and fine particles are contained only in the coating layer.

  In particular, from the viewpoint of transparency, when an inert particle is practically not contained in the polyester film, an inorganic and / or heat-resistant polymer particle is contained in the aqueous coating solution in order to improve the handleability of the film. It is also preferable to form irregularities on the surface of the coating layer.

  Note that “substantially no inert particles” means, for example, in the case of inorganic particles, when the element derived from the particles is quantitatively analyzed by fluorescent X-ray analysis, 50 ppm or less, preferably 10 ppm or less, Preferably, the content is below the detection limit. This means that even if particles are not actively added to the base film, contaminants derived from foreign substances and raw material resin or dirt adhering to the line or equipment in the film manufacturing process will be peeled off and mixed into the film. It is because there is a case to do.

  In addition, from the viewpoint of achieving both high transparency and handling properties, it is also a preferred embodiment to add inert particles only to the surface layer. For example, in the case of a three-layer structure, it is preferable that particles are contained in the outermost layer (A layer in the case of A layer / B layer / A layer), and the center layer (B layer) is substantially free of particles. .

  The type and content of the particles contained in the outermost layer may be inorganic particles or organic particles, and are not particularly limited, but include metal oxidation such as silica, titanium dioxide, talc, and kaolinite. Examples thereof include inorganic particles that are inert to polyesters such as products, calcium carbonate, calcium phosphate, and barium sulfate. Any one of these inert inorganic particles may be used alone, or two or more thereof may be used in combination.

  The particles preferably have an average particle size of 0.1 to 3.5 μm. If the average particle size is less than the lower limit, sufficient handling properties may not be obtained. If the upper limit is exceeded, the transparency may decrease. The content of inorganic particles in the outermost layer is preferably 0.01 to 0.20 mass% with respect to the polyester constituting the outermost layer. If it is less than the lower limit, sufficient handling properties cannot be obtained. When the upper limit is exceeded, the transparency decreases.

  Furthermore, when reflectivity and high concealability are required, a whitening film having a high void content may be used by adding a cavity developer in the base film. In applications where moldability is required, a molding film imparted with moldability by adding a copolymer component as a polyester resin may be used.

  The thickness of the base film used in the present invention is not particularly limited, but can be arbitrarily determined in the range of 30 to 500 μm according to the standard to be used. The upper limit of the thickness of the base film is preferably 350 μm, particularly preferably 250 μm. On the other hand, the lower limit of the film thickness is preferably 50 μm, more preferably 75 μm, and particularly preferably 100 μm. When the film thickness is less than the lower limit, rigidity and mechanical strength tend to be insufficient. On the other hand, when the film thickness exceeds the upper limit, the cost may increase.

(Coating layer)
In the easily adhesive polyester film of the present invention, it is important to provide a coating layer containing a urethane resin containing polycarbonate polyol as a constituent component and a carbodiimide compound as main components. Here, the “main component” means that 50% by mass or more is contained in the total solid component contained in the coating layer.

  As in the above Patent Documents 1 to 3, it has been considered that it is desirable to positively introduce a crosslinked structure in the formation of the coating layer from the viewpoint of improving the heat-and-moisture resistance of the coating layer according to conventional technical common sense. However, in the present invention, by combining a polyurethane resin and a carbodiimide compound, a remarkable effect that adhesion is improved under wet heat has been found, and the present invention has been achieved. Although the mechanism by which the adhesiveness under high temperature and high humidity is improved by such a configuration is not well understood, the present inventor thinks as follows.

  In the present invention, since the polyurethane resin and the carbodiimide compound are combined, unreacted carbodiimide groups remain when the coating layer is formed. Thereafter, the polyester resin constituting the base material is hydrolyzed under a high temperature and high humidity environment, the ester bond is broken, and a carboxylic acid group terminal is generated. Here, the unreacted carbodiimide group remaining in the coating layer reacts with the generated carboxylic acid terminal to form a crosslink. In other words, it is believed that a decrease in adhesion due to hydrolysis can be prevented by self-healing. Furthermore, in this invention, the more excellent heat-and-moisture resistance can be exhibited by using the polycarbonate-type urethane resin excellent in durability.

  The present invention can improve the adhesion (humidity heat resistance) of the lens layer and other functional layers under high temperature and high humidity according to the above aspect. Further, the configuration of the present invention will be described in detail below.

(Urethane resin)
The urethane resin of the present invention includes at least a polyol component and a polyisocyanate component as constituent components, and further includes a chain extender as necessary. The urethane resin of the present invention is a polymer compound in which these constituent components are mainly copolymerized by urethane bonds. In this invention, it has the polycarbonate polyol as a structural component of a urethane resin, It is characterized by the above-mentioned. Moisture heat resistance can be improved by including a urethane resin containing polycarbonate as a constituent component in the coating layer of the present invention. The components of these urethane resins can be specified by nuclear magnetic resonance analysis or the like.

  Examples of the polycarbonate polyol which is a constituent component of the urethane resin of the present invention include polycarbonate diol and polycarbonate triol. Polycarbonate diol can be preferably used. Examples of the polycarbonate diol that is a constituent component of the urethane resin of the present invention include ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, and 3-methyl-1,5. -Pentanediol, 1,6-hexanediol, 1,9-nonanediol, 1,8-nonanediol, neopentyl glycol, diethylene glycol, dipropylene glycol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, A polycarbonate diol obtained by reacting one or more diols such as bisphenol-A with carbonates such as dimethyl carbonate, diphenyl carbonate, ethylene carbonate, and phosgene. And the like. The number average molecular weight of the polycarbonate diol is preferably 300 to 5000, and more preferably 500 to 3000.

  In the present invention, the composition molar ratio of the polycarbonate polyol which is a constituent component of the urethane resin is preferably 3 to 100 mol%, and preferably 5 to 50 mol% when the total polyisocyanate component of the urethane resin is 100 mol%. More preferably, it is 6 to 20 mol%. When the composition molar ratio is low, the durability effect by the polycarbonate polyol may not be obtained. Moreover, when the said composition molar ratio is high, initial adhesiveness may fall.

  Examples of the polyisocyanate that is a constituent component of the urethane resin of the present invention include isomers of toluylene diisocyanate, aromatic diisocyanates such as 4,4-diphenylmethane diisocyanate, aromatic aliphatic diisocyanates such as xylylene diisocyanate, Aliphatic diisocyanates such as isophorone diisocyanate and 4,4-dicyclohexylmethane diisocyanate, 1,3-bis (isocyanatomethyl) cyclohexane, aliphatic diisocyanates such as hexamethylene diisocyanate, and 2,2,4-trimethylhexamethylene diisocyanate Or polyisocyanates obtained by adding these compounds in advance with trimethylolpropane or the like alone or in plural.

  Chain extenders include glycols such as ethylene glycol, diethylene glycol, 1,4-butanediol, neopentyl glycol and 1,6-hexanediol, polyhydric alcohols such as glycerin, trimethylolpropane, and pentaerythritol, ethylenediamine Diamines such as hexamethylenediamine and piperazine, aminoalcohols such as monoethanolamine and diethanolamine, thiodiglycols such as thiodiethylene glycol, and water.

  The coating layer of the present invention is preferably provided by an in-line coating method described later using an aqueous coating solution. Therefore, it is desirable that the urethane resin of the present invention is water-soluble. When a water-soluble urethane resin is used, compatibility with a carbodiimide compound increases, and transparency can be improved. The “water-soluble” means that it dissolves in water or an aqueous solution containing less than 50% by mass of a water-soluble organic solvent.

  In order to impart water solubility to the urethane resin, a sulfonic acid (salt) group or a carboxylic acid (salt) group can be introduced (copolymerized) into the urethane molecular skeleton. Since the sulfonic acid (salt) group is strongly acidic and it may be difficult to maintain moisture resistance due to its hygroscopic performance, it is preferable to introduce a weakly acidic carboxylic acid (salt) group.

  In order to introduce a carboxylic acid (salt) group into a urethane resin, for example, as a polyol component, a polyol compound having a carboxylic acid group such as dimethylolpropionic acid or dimethylolbutanoic acid is introduced as a copolymer component to form a salt. Neutralize with an agent. Specific examples of the salt forming agent include trialkylamines such as ammonia, trimethylamine, triethylamine, triisopropylamine, tri-n-propylamine, tri-n-butylamine, N such as N-methylmorpholine and N-ethylmorpholine. -N-dialkylalkanolamines such as alkylmorpholines, N-dimethylethanolamine, N-diethylethanolamine and the like. These can be used alone or in combination of two or more.

  In order to impart water solubility, when a polyol compound having a carboxylic acid (salt) group is used as a copolymerization component, the composition molar ratio of the polyol compound having a carboxylic acid (salt) group in the urethane resin is the same as that of the urethane resin. When the total polyisocyanate component is 100 mol%, it is preferably 3 to 60 mol%, more preferably 10 to 40 mol%. If the composition molar ratio is less than 3 mol%, water dispersibility may be difficult. Moreover, when the said composition molar ratio exceeds 60 mol%, since the residual carbodiimide group at the time of coating layer formation reduces, heat-and-moisture resistance may fall.

  However, when a urethane resin into which a carboxylic acid is introduced is used as the urethane resin as described above, it may react with the carbodiimide group in the coating solution, and the unreacted carbodiimide group may be reduced when the coating layer is formed. Therefore, it is desirable that the coating layer has substantially no carboxylic acid (salt) group. Therefore, in order to impart water solubility to the urethane resin, it is a preferred embodiment of the present invention to introduce a polyoxyalkylene group instead of the carboxylate group. When using the urethane resin which introduce | transduced the polyoxyalkylene group as a urethane resin, a coating layer does not have a carboxyl group substantially. Therefore, an unreacted carbodiimide group remains stably and can exhibit more excellent moisture and heat resistance.

  Examples of the polyoxyalkylene group introduced into the urethane resin include a polyoxyethylene group, a polyoxypropylene group, and a polytetramethylene glycol chain. These can be used alone or in combination of two or more. Among these, a polyoxyethylene group can be preferably used.

  In order to introduce a polyoxyethylene group into a urethane resin, for example, polyisocyanate and one-end blocked polyoxyethylene glycol (alkoxyethylene glycol having one end sealed with an alkyl group having 1 to 20 carbon atoms) are blocked at one end. After the urethanation reaction at an excess ratio of the isocyanate group of the diisocyanate with respect to the hydroxyl group of the polyoxyethylene glycol, the polyoxyethylene chain-containing monoisocyanate was obtained by removing the unreacted polyisocyanate if necessary. Then, the obtained polyoxyethylene chain-containing monoisocyanate and diisocyanate can be obtained by an allophanatization reaction.

  In order to impart water solubility, when introducing polyoxyethylene groups into the urethane resin, the composition molar ratio of the polyoxyethylene groups in the urethane resin is 100 mol% of the total polyisocyanate component of the urethane resin. It is preferably 3 mol% or more, more preferably 10 mol% or more, and further preferably 20 mol% or more. If the composition molar ratio is less than 3 mol%, water dispersibility may be difficult.

  The urethane resin is preferably contained in the coating layer in an amount of 10% by mass to 90% by mass. In particular, when high adhesion is required as in a lens layer, it is more preferably 20% by mass or more and 80% by mass or less. When the content of the urethane resin is large, the adhesiveness under high temperature and high humidity is lowered, and conversely, when the content is small, the initial adhesiveness is lowered.

  In the present invention, a resin other than the urethane resin may be contained in order to improve adhesion. For example, an acrylic resin, a polyester resin, etc. are mentioned. Preferably, the carboxylic acid group content is low. More preferably, it does not contain a carboxylic acid group. When there are many carboxylic acid groups, it will react with a carbodiimide group, and the carbodiimide group which reacts with the carboxylic acid group generated from a urethane resin under high temperature and high humidity will decrease.

  In the present invention, it is necessary to contain a carbodiimide compound. Examples of the carbodiimide compound include a monocarbodiimide compound and a polycarbodiimide compound.

  Examples of the monocarbodiimide compound include dicyclohexylcarbodiimide, diisopropylcarbodiimide, dimethylcarbodiimide, diisobutylcarbodiimide, dioctylcarbodiimide, t-butylisopropylcarbodiimide, diphenylcarbodiimide, di-t-butylcarbodiimide, and di-β-naphthylcarbodiimide. .

  As the polycarbodiimide compound, those produced by a conventionally known method can be used. For example, it can be produced by synthesizing an isocyanate-terminated polycarbodiimide by a condensation reaction involving decarbonization of diisocyanate.

  Examples of the diisocyanate that is a raw material for synthesizing the polycarbodiimide compound include isomers of toluylene diisocyanate, aromatic diisocyanates such as 4,4-diphenylmethane diisocyanate, aromatic aliphatic diisocyanates such as xylylene diisocyanate, isophorone diisocyanate and 4 , 4-dicyclohexylmethane diisocyanate, alicyclic diisocyanates such as 1,3-bis (isocyanatomethyl) cyclohexane, hexamethylene diisocyanate, and aliphatic diisocyanates such as 2,2,4-trimethylhexamethylene diisocyanate. From the problem of yellowing, aromatic aliphatic diisocyanates, alicyclic diisocyanates, and aliphatic diisocyanates are preferred.

The diisocyanate may be used with a molecule controlled to an appropriate degree of polymerization using a compound that reacts with a terminal isocyanate such as monoisocyanate. Examples of monoisocyanates for sealing the ends of polycarbodiimide and controlling the degree of polymerization thereof include phenyl isocyanate, toluylene isocyanate, dimethylphenyl isocyanate, cyclohexyl isocyanate, butyl isocyanate, and naphthyl isocyanate. In addition, a compound having an OH group, —NH ₂ group, COOH group, or SO ₃ H group can be used as a terminal blocking agent.

  The condensation reaction involving decarbonization of diisocyanate proceeds in the presence of a carbodiimidization catalyst. Examples of the catalyst include 1-phenyl-2-phospholene-1-oxide, 3-methyl-2-phospholene-1-oxide, 1-ethyl-2-phospholene-1-oxide, and 3-methyl-1-phenyl-2. -Phosphorene-1-oxide, phospholene oxides such as these 3-phospholene isomers and the like can be mentioned, and 3-methyl-1-phenyl-2-phospholene-1-oxide is preferable from the viewpoint of reactivity. The amount of the catalyst used can be a catalyst amount.

  The mono- or polycarbodiimide compound described above is desirably kept in a uniform dispersed state when blended with an aqueous coating material. For this purpose, it is emulsified with an appropriate emulsifier and used as an emulsion, or a polycarbodiimide compound. It is preferable to add a hydrophilic segment in the molecular structure of the compound and mix it with the paint in the form of a self-emulsified product or in the form of a self-dissolved product.

  As a polymerization degree (n) of a polycarbodiimide compound, 2-10 are preferable, More preferably, it is 3-7. When the degree of polymerization is small, the crosslinking reaction rate is deteriorated and the adhesion with the functional layer is lowered. When the degree of polymerization is large, the compatibility with the resin is deteriorated and haze may be increased.

  Examples of the carbodiimide compound used in the present invention include water dispersibility and water solubility. Water solubility is preferred because it is highly compatible with other water-soluble resins and improves the transparency of the coating layer and the crosslinking reaction efficiency.

  In order to make a carbodiimide compound water-soluble, an isocyanate-terminated polycarbodiimide is synthesized by a condensation reaction involving decarbonization of isocyanate, and then a hydrophilic part having a functional group having reactivity with an isocyanate group is added. Can be manufactured.

  Examples of hydrophilic sites include (1) quaternary ammonium salts of dialkylamino alcohols and quaternary ammonium salts of dialkylaminoalkylamines, (2) alkyl sulfonates having at least one reactive hydroxyl group, and the like (3) Examples thereof include poly (ethylene oxide) end-capped with an alkoxy group, poly (propylene oxide), a mixture of poly (ethylene oxide) and poly (propylene oxide), and the like. 3-50 are preferable and, as for the repeating unit of ethylene oxide and / or propylene oxide, More preferably, it is 5-35. When the repeating unit is small, the compatibility with the resin is deteriorated and the haze is increased. When the repeating unit is large, the adhesiveness under high temperature and high humidity may be decreased. The carbodiimide compound is (1) cationic, (2) anionic, and (3) nonionic when the above hydrophilic moiety is introduced. Especially, the nonionic property which can be compatible regardless of the ionicity of other water-soluble resin is preferable. Moreover, in order to improve heat-and-moisture resistance, the nonionic property which does not need to introduce | transduce an ionic hydrophilic group is preferable.

  The carbodiimide compound is preferably contained in the coating layer in an amount of 5% by mass to 90% by mass. More preferably, it is 10% by mass or more and 70% by mass or less. When the content of the carbodiimide compound is large, the adhesion with the functional layer is lowered, and conversely, when the content is small, the adhesion under high temperature and high humidity may be lowered.

  In the present invention, in order to improve the coating film strength, the coating layer may contain a crosslinking agent different from the carbodiimide compound or a resin having a crosslinking group. Examples of the crosslinking agent include urea, epoxy, melamine, isocyanate, oxazoline, silanol and the like. Moreover, in order to promote a crosslinking reaction, a catalyst etc. are used suitably as needed.

  In the present invention, particles may be contained in the coating layer. Particles are (1) silica, kaolinite, talc, light calcium carbonate, heavy calcium carbonate, zeolite, alumina, barium sulfate, carbon black, zinc oxide, zinc sulfate, zinc carbonate, titanium dioxide, zirconium dioxide, tin oxide, satin White, titanium black, aluminum silicate, diatomaceous earth, calcium silicate, aluminum hydroxide, hydrous halloysite, magnesium carbonate, magnesium hydroxide, inorganic particles, (2) acrylic or methacrylic, vinyl chloride, vinyl acetate, Nylon, styrene / acrylic, styrene / butadiene, polystyrene / acrylic, polystyrene / isoprene, polystyrene / isoprene, methyl methacrylate / butyl methacrylate, melamine, polycarbonate, urea , Epoxy, urethane, phenolic, diallyl phthalate, and organic particles of a polyester or the like.

  The particles preferably have an average particle size of 1 to 500 nm. Although an average particle diameter is not specifically limited, If it is 1-100 nm from the point which maintains the transparency of a film, it is preferable.

  The particles may contain two or more kinds of particles having different average particle diameters.

  In addition, said average particle diameter measures the maximum diameter of the 10 or more particle | grains which exist in the cross section of a coating layer by image | photographing the cross section of a laminated film at a magnification of 120,000 times using a transmission electron microscope (TEM). And can be obtained as an average value of them.

  As content of particle | grains, 0.5 mass% or more and 20 mass% or less are preferable. When the amount is small, sufficient blocking resistance cannot be obtained. Further, scratch resistance is deteriorated. When the amount is large, not only the transparency of the coating layer is deteriorated, but also the coating strength is lowered.

  The coating layer may contain a surfactant for the purpose of improving leveling properties during coating and defoaming the coating solution. The surfactant may be any of cationic, anionic and nonionic surfactants, but is preferably a silicon-based, acetylene glycol-based or fluorine-based surfactant. These surfactants are preferably contained in a range that does not impair the adhesion to the functional layer, for example, in the range of 0.005 to 0.5% by mass in the coating solution.

  The easily adhesive polyester film of the present invention preferably has a haze value of 2.5% or less, more preferably 2.0% or less, and further preferably 1.5% or less. Such an easily adhesive polyester film can be improved in compatibility with other resins by making the carbodiimide compound contained in the coating layer described above water-soluble.

  In order to impart other functionality to the coating layer, various additives may be contained within a range that does not impair the adhesion to the functional layer. Examples of the additive include fluorescent dyes, fluorescent brighteners, plasticizers, ultraviolet absorbers, pigment dispersants, foam suppressors, antifoaming agents, preservatives, and antistatic agents.

  In the present invention, examples of the method for providing the coating layer on the polyester film include a method in which a coating solution containing a solvent, particles and a resin is applied to the polyester film and dried. Examples of the solvent include organic solvents such as toluene, water, and a mixed system of water and a water-soluble organic solvent. Preferably, water alone or a mixture of a water-soluble organic solvent and water is used from the viewpoint of environmental problems. preferable.

  The laminated polyester film of the present invention is selected from a hard coat layer, a light diffusion layer, a prismatic lens layer, an electromagnetic wave absorption layer, a near infrared ray blocking layer, and a transparent conductive layer on at least one side of the above-mentioned polyester film coating layer. It is obtained by at least one optical functional layer.

  The material used for the optical function layer is not particularly limited.

(Manufacture of easily adhesive polyester film)
The production method of the easily adhesive polyester film of the present invention will be described by taking a polyethylene terephthalate (hereinafter abbreviated as PET) film as an example, but is not limited to this.

  After sufficiently drying the PET resin in a vacuum, it is supplied to an extruder, melted and extruded at about 280 ° C. from a T-die into a rotating cooling roll into a sheet, cooled and solidified by an electrostatic application method, and unstretched PET. Get a sheet. The unstretched PET sheet may have a single layer structure or a multilayer structure by a coextrusion method. Moreover, it is preferable not to contain an inert particle substantially in PET resin.

  The obtained unstretched PET sheet is stretched 2.5 to 5.0 times in the longitudinal direction with a roll heated to 80 to 120 ° C. to obtain a uniaxially stretched PET film. Furthermore, the edge part of a film is hold | gripped with a clip, it guide | induces to the hot air zone heated at 70-140 degreeC, and is extended | stretched 2.5 to 5.0 times in the width direction. Then, it guide | induces to the heat processing zone of 160-240 degreeC, and heat-processes for 1 to 60 seconds, and completes crystal orientation.

  In an arbitrary stage of the film manufacturing process, a coating solution is applied to at least one surface of the PET film to form the coating layer. There is no particular problem even if the coating layer is formed on both sides of the PET film. The solid content concentration of the resin composition in the coating solution is preferably 2 to 35% by weight, particularly preferably 4 to 15% by weight.

  Any known method can be used as a method for applying the coating solution to the PET film. For example, reverse roll coating method, gravure coating method, kiss coating method, die coater method, roll brush method, spray coating method, air knife coating method, wire bar coating method, pipe doctor method, impregnation coating method, curtain coating method, etc. It is done. These methods are applied alone or in combination.

  In the present invention, the coating layer is formed by coating the coating solution on an unstretched or uniaxially stretched PET film, drying it, stretching in at least a uniaxial direction, and then performing a heat treatment.

In the present invention, the finally obtained coating layer preferably has a thickness of 20 to 350 nm, and the coating amount after drying is preferably 0.02 to 0.5 g / m ² . When the coating amount of the coating layer is less than 0.02 g / m ² , the effect on adhesiveness is almost lost. On the other hand, when the coating amount exceeds 0.5 g / m ² , haze increases.

  The coating layer of the easy-adhesive thermoplastic resin film obtained in the present invention has good adhesion to a hard coat layer, a light diffusion layer, a prismatic lens layer, an electromagnetic wave absorption layer, a near-infrared shielding layer, and a transparent conductive layer. Have By laminating these optical functional layers, it is possible to provide an optical laminated thermoplastic resin film that can maintain an initial function for a long period of time even in a moisture and heat resistant environment. Also, good adhesive strength can be obtained even for applications other than optical applications. Specifically, adhesion such as photographic photosensitive layer, diazo photosensitive layer, matte layer, magnetic layer, inkjet ink receiving layer, hard coat layer, UV curable resin, thermosetting resin, printing ink and UV ink, dry laminate, extrusion laminate, etc. Examples thereof include vacuum deposition, electron beam deposition, sputtering, ion plating, CVD, plasma polymerization and the like of an agent, a metal or an inorganic substance, or an oxide thereof, and an organic barrier layer.

  EXAMPLES Next, although this invention is demonstrated in detail using an Example and a comparative example, naturally this invention is not limited to a following example. The evaluation method used in the present invention is as follows.

(1) Intrinsic viscosity Based on JIS K7367-5, it measured at 30 degreeC, using the mixed solvent of phenol (60 mass%) and 1,1,2,2-tetrachloroethane (40 mass%) as a solvent.

(2) Resin composition The resin was dissolved in deuterated chloroform, ¹ H-NMR analysis was performed using a nuclear magnetic resonance analyzer (NMR) Gemini-200 manufactured by Varian, and 100 moles of all isocyanate components were determined from the integration ratio. The mole% ratio of each composition was determined.

(3) Total light transmittance of easy-adhesive polyester film The total light transmittance of the obtained easily-adhesive polyester film was measured using a turbidimeter (Nippon Denshoku, NDH2000) in accordance with JIS K 7105. .

(4) Haze of easy-adhesive polyester film The haze of the obtained easy-adhesive polyester film was measured using a turbidimeter (Nippon Denshoku, NDH2000) in accordance with JIS K7136.

(5) Adhesiveness 100 grid-like shapes reaching the base film through the photocurable acrylic layer on the photocurable acrylic layer surface of the obtained laminated polyester film using a cutter guide with a gap distance of 2 mm Make a cut. Next, a cellophane adhesive tape (manufactured by Nichiban Co., Ltd., No. 405; 24 mm width) was attached to the cut surface of the grid and rubbed with an eraser for complete adhesion. Then, after performing the work of peeling the cellophane adhesive tape vertically from the photocurable acrylic layer surface of the laminated polyester film 5 times, the number of squares peeled off from the photocurable acrylic layer surface of the laminated polyester film was visually counted, From the formula, the adhesion between the photocurable acrylic layer and the substrate film was determined. In addition, what peeled partially among squares was also counted as the square which peeled, and was ranked according to the following references | standards.
Adhesiveness (%) = (1−number of peeled squares / 100) × 100
A: 100%, or material breakage of photocurable acrylic layer B: 99-90%
Δ: 89-70%
X: 69 to 0%

(6) Moisture and heat resistance The obtained laminated polyester film was allowed to stand in an environment of 80 ° C. and 95% RH for 48 hours in a high temperature and high humidity tank. Next, the laminated polyester film was taken out and allowed to stand at room temperature and humidity for 12 hours. Thereafter, the adhesiveness between the photocurable acrylic layer and the substrate film is the same as the above (5) except that the cellophane adhesive tape is peeled off from the photocurable acrylic layer surface of the laminated polyester film five times. Was ranked according to the following criteria.
A: 100%, or material breakage of photocurable acrylic layer B: 99-90%
Δ: 89-70%
X: 69 to 0%

(Polymerization of urethane resin containing polycarbonate polyol)
In a four-necked flask equipped with a stirrer, a Dimroth cooler, a nitrogen inlet tube, a silica gel drying tube, and a thermometer, 72.96 parts by mass of 1,3-bis (isocyanatomethyl) cyclohexane, 12.60 dimethylolpropionic acid. Mass part, 11.74 parts by mass of neopentyl glycol, 112.70 parts by mass of polycarbonate diol having a number average molecular weight of 2000, and 85.00 parts by mass of acetonitrile and 5.00 parts by mass of N-methylpyrrolidone as a solvent were added, and a nitrogen atmosphere Under stirring at 75 ° C. for 3 hours, it was confirmed that the reaction solution reached a predetermined amine equivalent. Next, after lowering the temperature of the reaction solution to 40 ° C., 9.03 parts by mass of triethylamine was added to obtain a polyurethane prepolymer D solution. Next, 450 g of water was added to a reaction vessel equipped with a homodisper capable of high-speed stirring, adjusted to 25 ° C., and mixed with stirring at 2000 min −1 while adding an isocyanate group-terminated prepolymer to disperse in water. did. Then, water-soluble polyurethane resin (A-1) with a solid content of 35% was prepared by removing a portion of acetonitrile and water under reduced pressure.

In the same manner, water-soluble polyurethane resins (A-2) to (A-3) having different compositions were obtained. Table 1 shows the composition (mol% ratio) and other characteristics measured by ¹ H-NMR for these water-soluble polyurethane resins.

(Polymerization of polycarbonate resin and polyoxyethylene group urethane resin)
In a reactor equipped with a thermometer, a nitrogen gas inlet tube and a stirrer, while introducing nitrogen gas, 627.1 parts by mass of hexamethylene diisocyanate and methoxypolyethylene glycol 372.9 having a number average molecular weight of 1000 heated to 50 ° C. A mass part was charged and reacted at 80 ° C. for 6 hours. After reaching a predetermined isocyanate group content, unreacted hexamethylene diisocyanate was removed with a Smith type thin film distiller to obtain a polyoxyethylene group-containing monoisocyanate (A). The calculated number average molecular weight of this polyoxyethylene chain-containing monoisocyanate (A) was 1168 g / mol.

  Next, 83.9 parts by mass of diethanolamine was charged while introducing nitrogen gas at room temperature in a reactor equipped with a thermometer, a nitrogen gas introduction tube, and a stirrer. While cooling, 916.1 parts by mass of polyisocyanate chain-containing monoisocyanate A was added and reacted at 60 ° C. for 3 hours. Formation of urea bonds was confirmed by infrared spectrum, and a polyoxyethylene group-containing polyol (A) was obtained.

  In a four-necked flask equipped with a reflux condenser, a nitrogen inlet tube, a thermometer, and a stirrer, 53.69 parts by mass of 1,3-cyclohexanebis (methyl isocyanate) as a polyisocyanate and several as a hydrophobic macropolyol Polycarbonate diol having an average molecular weight of 2000, 88.6 parts by mass, 14.97 parts by mass of neopentyl glycol, 52.87 parts by mass of the polyoxyethylene group-containing polyol (A), 60 parts by mass of acetonitrile as an organic solvent, N -30 parts by mass of methylpyrrolidone was charged, the temperature of the reaction solution was adjusted to 75 to 78 ° C under a nitrogen atmosphere, 0.06 parts by mass of stannous octylate was added as a reaction catalyst, and the reaction rate was 99 in 7 hours. It was made to react to more than%. Subsequently, this was cooled to 30 degreeC and the isocyanate group terminal prepolymer was obtained. Next, 450 g of water was added to a reaction vessel equipped with a homodisper capable of high-speed stirring, adjusted to 25 ° C., and mixed with stirring at 2000 min −1 while adding an isocyanate group-terminated prepolymer to disperse in water. did. Then, water-soluble polyurethane resin (A-4) with a solid content of 35% was prepared by removing a portion of acetonitrile and water under reduced pressure.

(Polymerization of urethane resin with polyester polyol as a constituent)
In a four-necked flask equipped with a stirrer, a Dimroth cooler, a nitrogen inlet tube, a silica gel drying tube, and a thermometer, 72.96 parts by mass of 1,3-bis (isocyanatomethyl) cyclohexane, 12.60 dimethylolpropionic acid. Mass part, neopentyl glycol 11.74 parts by mass, number average molecular weight 2000 polyester diol 112.70 parts by mass, acetonitrile 85.00 parts by mass, N-methylpyrrolidone 5.00 parts by mass as a solvent, nitrogen atmosphere Under stirring at 75 ° C. for 3 hours, it was confirmed that the reaction solution reached a predetermined amine equivalent. Next, after lowering the temperature of the reaction solution to 40 ° C., 9.03 parts by mass of triethylamine was added to obtain a polyurethane prepolymer solution. Next, 450 g of water was added to a reaction vessel equipped with a homodisper capable of high-speed stirring, adjusted to 25 ° C., and mixed with stirring at 2000 min −1 while adding an isocyanate group-terminated prepolymer to disperse in water. did. Thereafter, a part of acetonitrile and water was removed under reduced pressure to prepare a water-soluble polyurethane resin (A-5) having a solid content of 35%.

(Polymerization of urethane resin containing polyether polyol)
In a four-necked flask equipped with a stirrer, a Dimroth cooler, a nitrogen inlet tube, a silica gel drying tube, and a thermometer, 72.96 parts by mass of 1,3-bis (isocyanatomethyl) cyclohexane, 12.60 dimethylolpropionic acid. Mass part, 11.74 parts by mass of neopentyl glycol, 112.70 parts by mass of polyether diol having a number average molecular weight of 2000, and 85.00 parts by mass of acetonitrile and 5.00 parts by mass of N-methylpyrrolidone as a solvent, The mixture was stirred at 75 ° C. for 3 hours under an atmosphere, and it was confirmed that the reaction solution reached a predetermined amine equivalent. Next, after lowering the temperature of the reaction solution to 40 ° C., 9.03 parts by mass of triethylamine was added to obtain a polyurethane prepolymer solution. Next, 450 g of water was added to a reaction vessel equipped with a homodisper capable of high-speed stirring, adjusted to 25 ° C., and mixed with stirring at 2000 min −1 while adding an isocyanate group-terminated prepolymer to disperse in water. did. Thereafter, a part of acetonitrile and water was removed under reduced pressure to prepare a water-soluble polyurethane resin (A-6) having a solid content of 35%.

(Polymerization of water-soluble carbodiimide compounds)
In a flask equipped with a thermometer, nitrogen gas introduction tube, reflux condenser, dropping funnel, and stirrer, 200 parts by mass of isophorone diisocyanate and 4 parts by mass of 3-methyl-1-phenyl-2-phospholene-1-oxide as a carbodiimidization catalyst And stirred at 180 ° C. for 10 hours under a nitrogen atmosphere to obtain an isocyanate-terminated isophorone carbodiimide (degree of polymerization = 5). Next, 111.2 g of the obtained carbodiimide and 80 g of polyethylene glycol monomethyl ether (molecular weight 400) were reacted at 100 ° C. for 24 hours. Water was gradually added thereto at 50 ° C. to obtain a yellow transparent water-soluble carbodiimide compound (B-1) having a solid content of 40% by mass.

(Polymerization of water-soluble carbodiimide compounds)
In a flask equipped with a thermometer, nitrogen gas inlet tube, reflux condenser, dropping funnel, and stirrer, 200 parts by mass of 4,4-dicyclohexylmethane diisocyanate, carbodiimidization catalyst 3-methyl-1-phenyl-2-phospholene-1 4 parts by mass of oxide were added and stirred at 180 ° C. for 8 hours under a nitrogen atmosphere to obtain isocyanate-terminated 4,4-dicyclohexylmethane (degree of polymerization = 2). Subsequently, 69.9 g of the obtained carbodiimide and 80 g of polyethylene glycol monomethyl ether (molecular weight 400) were reacted at 100 ° C. for 24 hours. Water was gradually added thereto at 50 ° C. to obtain a yellow transparent water-soluble carbodiimide compound (B-2) having a solid content of 40% by mass.

(Polymerization of water-soluble carbodiimide compounds)
In a flask equipped with a thermometer, nitrogen gas inlet tube, reflux condenser, dropping funnel, and stirrer, 200 parts by mass of 4,4-dicyclohexylmethane diisocyanate, carbodiimidization catalyst 3-methyl-1-phenyl-2-phospholene-1 4 parts by mass of oxide were added and stirred at 180 ° C. for 30 hours in a nitrogen atmosphere to obtain isocyanate-terminated 4,4-dicyclohexylmethane (degree of polymerization = 10). Next, 244.6 g of the obtained carbodiimide and 150 g of polyethylene glycol monomethyl ether (molecular weight 750) were reacted at 100 ° C. for 24 hours. Water was gradually added thereto at 50 ° C. to obtain a yellow transparent water-soluble carbodiimide compound (B-3) having a solid content of 40% by mass.

(Polymerization of water-dispersible carbodiimide compound)
In a flask equipped with a thermometer, a nitrogen gas introduction tube, a reflux condenser, a dropping funnel, and a stirrer, 200 parts by mass of isophorone diisocyanate, 25 parts by mass of cyclohexyl isocyanate, 3-methyl-1-phenyl-2-phospholene as a carbodiimidization catalyst 2.5 parts by mass of 1-oxide was added and stirred for 30 hours at 180 ° C. in a nitrogen atmosphere to obtain isophorone carbodiimide (degree of polymerization = 10). Next, nonylphenol nonionic surfactant (Sanyo Kasei nonipol) diluted with water to a solid content concentration of 0.5% by mass was gradually added to 100 g of the obtained carbodiimide resin to obtain a water-dispersible carbodiimide having a solid content of 40% by mass. Compound (C) was obtained.

Example 1
(1) Adjustment of coating liquid The following coating agent was mixed and the coating liquid was created.
51.00% by mass of water
Isopropanol 30.00% by mass
Polyurethane resin (A-1) 12.58 mass%
Water-soluble carbodiimide compound (B-1) 4.72% by mass
Particles 1.57% by mass
(Silica sol with an average particle size of 40 nm, solid content concentration of 40% by mass)
0.08% by mass of particles
(Silica sol with an average particle size of 450 nm, solid content concentration of 40% by mass)
Surfactant 0.05% by mass
(Silicon, solid content concentration of 100% by mass)

(2) Production of easy-adhesive polyester film PET film pellets having an intrinsic viscosity of 0.62 dl / g and substantially free of particles as a film raw material polymer are dried at 135 ° C. for 6 hours under a reduced pressure of 133 Pa. did. Thereafter, the sheet was supplied to an extruder, melted and 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.

  This unstretched PET sheet was heated to 100 ° C. with a heated roll group and an infrared heater, and then stretched 3.5 times in the longitudinal direction with a roll group having a difference in peripheral speed to obtain a uniaxially stretched PET film.

Subsequently, after apply | coating the said coating liquid on the single side | surface of PET film by the roll coat method, it dried at 80 degreeC for 20 second. The final coating amount (after biaxial stretching) was adjusted so that the coating amount after drying was 0.15 g / m ² . Subsequently, the film was stretched 4.0 times in the width direction at 120 ° C. with a tenter, and heated at 230 ° C. for 0.5 seconds with the length in the width direction fixed, and further at 230 ° C. for 10 seconds. % Relaxation treatment in the width direction was performed to obtain an easily adhesive polyester film having a thickness of 100 μm. The evaluation results are shown in Table 2.

(3) Manufacture of a laminated polyester film About 5 g of the following photocurable acrylic coating solution is placed on a 1 mm thick SUS plate (SUS304) kept clean, and the coating layer surface of the film sample and the photocurable acrylic coating solution And a pressure-sensitive acrylic coating liquid was stretched by a manually loaded rubber roller having a width of 10 cm and a diameter of 4 cm from above the film sample. Subsequently, 800 mJ / cm < ² > of ultraviolet rays were irradiated from the film surface side using the high pressure mercury lamp, and the photocurable acrylic resin was hardened. A film sample having a photocurable acrylic layer having a thickness of 20 μm was peeled from the SUS plate to obtain a laminated polyester film.
Photo-curing acrylic coating liquid 54.00% by mass
(Arakawa Chemical Industries Beam Set 505A-6)
Photo-curing acrylic resin 36.00% by mass
(Arakawa Chemical Beam Set 550)
Photopolymerization initiator 10.00% by mass
(Irgacure 184 manufactured by Ciba Specialty Chemicals)

Comparative Example 1
An easily adhesive polyester film and a laminated polyester film were obtained in the same manner as in Example 1 except that the polyurethane resin was changed to a polyurethane resin (A-5) containing polyester polyol as a constituent component.

Comparative Example 2
An easily adhesive polyester film and a laminated polyester film were obtained in the same manner as in Example 1 except that the polyurethane resin was changed to a polyurethane resin (A-6) containing polyether polyol as a constituent component.

Comparative Example 3
An easy-adhesive polyester film and a laminated polyester film were prepared in the same manner as in Example 1 except that the water-soluble carbodiimide compound (B-1) was changed to an epoxy compound (Denacol EX-521, solid content concentration 100%, manufactured by Nagase ChemteX Corporation). Obtained.

Comparative Example 4
An easy-adhesive polyester film and a laminated polyester film were obtained in the same manner as in Example 1 except that the water-soluble carbodiimide compound (B-1) was changed to a melamine compound (Becamine M-3 solid concentration 60% manufactured by DIC). .

Example 2
An easily adhesive polyester film and a laminated polyester film were obtained in the same manner as in Example 1 except that the polyurethane resin was changed to a polyurethane resin (A-2) containing polycarbonate polyol as a constituent component.

Example 3
An easily adhesive polyester film and a laminated polyester film were obtained in the same manner as in Example 1 except that the polyurethane resin was changed to a polyurethane resin (A-3) containing polycarbonate polyol as a constituent component.

Example 4
An easy-adhesive polyester film and a laminated polyester film are obtained in the same manner as in Example 1 except that the polyurethane resin is changed to a urethane resin (A-4) having polycarbonate polyol as a constituent component and having a polyoxyethylene glycol chain in the side chain. It was.

Example 5
An easily adhesive polyester film and a laminated polyester film were obtained in the same manner as in Example 1 except that the water-soluble carbodiimide compound (B-1) was changed to the water-dispersible carbodiimide compound (C).

Example 6
An easy-adhesive polyester film and a laminated polyester film were obtained in the same manner as in Example 1 except that the coating solution was changed to the following.
Water 50.44% by mass
Isopropanol 30.00% by mass
Polyurethane resin (A-1) 17.07 mass%
Water-soluble carbodiimide compound (B-1) 0.79 mass%
Particles 1.57% by mass
(Silica sol with an average particle size of 40 nm, solid content concentration of 40% by mass)
0.08% by mass of particles
(Silica sol with an average particle size of 450 nm, solid content concentration of 40% by mass)
Surfactant 0.05% by mass
(Silicon, solid content concentration of 100% by mass)

Example 7
An easy-adhesive polyester film and a laminated polyester film were obtained in the same manner as in Example 1 except that the coating solution was changed to the following.
Water 52.24% by mass
Isopropanol 30.00% by mass
Polyurethane resin (A-1) 2.70% by mass
Water-soluble carbodiimide compound (B-1) 13.36 mass%
Particles 1.57% by mass
(Silica sol with an average particle size of 40 nm, solid content concentration of 40% by mass)
0.08% by mass of particles
(Silica sol with an average particle size of 450 nm, solid content concentration of 40% by mass)
Surfactant 0.05% by mass
(Silicon, solid content concentration of 100% by mass)

Example 8
An easy-adhesive polyester film and a laminated polyester film were obtained in the same manner as in Example 1 except that the coating solution was changed to the following.
Water 51.90 mass%
Isopropanol 30.00% by mass
Polyurethane resin (A-1) 5.39% by mass
Water-soluble carbodiimide compound (B-1) 11.01 mass%
Particles 1.57% by mass
(Silica sol with an average particle size of 40 nm, solid content concentration of 40% by mass)
0.08% by mass of particles
(Silica sol with an average particle size of 450 nm, solid content concentration of 40% by mass)
Surfactant 0.05% by mass
(Silicon, solid content concentration of 100% by mass)

Example 9
An easy-adhesive polyester film and a laminated polyester film were obtained in the same manner as in Example 1 except that the coating solution was changed to the following.
Water 50.78% by mass
Isopropanol 30.00% by mass
Polyurethane resin (A-1) 14.38 mass%
Water-soluble carbodiimide compound (B-1) 3.14% by mass
Particles 1.57% by mass
(Silica sol with an average particle size of 40 nm, solid content concentration of 40% by mass)
0.08% by mass of particles
(Silica sol with an average particle size of 450 nm, solid content concentration of 40% by mass)
Surfactant 0.05% by mass
(Silicon, solid content concentration of 100% by mass)

Example 10
An easily adhesive polyester film and a laminated polyester film were obtained in the same manner as in Example 1 except that the water-soluble carbodiimide compound (B-1) was changed to the water-soluble carbodiimide compound (B-2).

Example 11
An easily adhesive polyester film and a laminated polyester film were obtained in the same manner as in Example 1 except that the water-soluble carbodiimide compound (B-1) was changed to the water-soluble carbodiimide compound (B-3).

  The easily adhesive polyester film of the present invention is excellent in adhesion with an optical functional layer and adhesion under high temperature and high humidity (moisture and heat resistance), so that it is mainly used for displays and the like, and a reflection using the film. It is suitable as a base film for optical functional films such as prevention films, light diffusion sheets, prismatic lens sheets, near-infrared shielding films, transparent conductive films, and antiglare films.

Claims (4)

An easily adhesive polyester film having a coating layer on at least one side of the polyester film,
An easy-adhesive polyester film in which the coating layer is mainly composed of a urethane resin containing polycarbonate polyol as a constituent component and a carbodiimide compound.   The easily adhesive polyester film according to claim 1, wherein the urethane resin has a polyoxyalkylene group.   The easily adhesive polyester film according to claim 1 or 2, wherein the carbodiimide compound is water-soluble and has a haze of 2.5% or less.   The hard-coat layer, the light diffusion layer, the prismatic lens layer, the electromagnetic wave absorption layer, the near-infrared blocking layer, and the transparent conductive layer are selected as the coating layer of the easily adhesive polyester film according to any one of claims 1 to 3. A laminated polyester film obtained by laminating at least one functional layer.