JP2011153289A - Easily adhesive thermoplastic resin film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an easily adhesive thermoplastic resin film having excellent adhesiveness and moist heat resistance. <P>SOLUTION: The easily adhesive thermoplastic resin film includes a coated layer at least on one surface of a base material film. The coated layer contains a polycarbonate-based urethane resin, and further contains 0.5-3.5 mmol/g of a carbodiimide group. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a thermoplastic resin film excellent in adhesion and moisture and heat resistance. Specifically, it is suitable as a base film for optical functional films such as hard coat films, antireflection films, light diffusion sheets, 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 a thermoplastic resin film.

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

  When the thermoplastic resin film is used as a base material for various optical functional films, optical 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 external light from being reflected, and a lens layer that is used to collect and diffuse light And an optical functional layer such as a light diffusion layer for improving luminance. Among such substrates, particularly polyester films are widely used as substrates for various optical functional films because they are excellent in transparency, dimensional stability and chemical resistance and are relatively inexpensive.

  Generally, when using as a base film for laminating | stacking a functional layer, in order to improve adhesiveness with a functional layer, the method of providing easy-adhesiveness by various methods is proposed. For example, a method of imparting 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 thermoplastic resin film of the base Is generally known. Among these coating methods, an aqueous coating solution containing the resin solution or a dispersion in which the resin is dispersed in a dispersion medium is applied to a base film with a thermoplastic resin film before crystal orientation is completed in a stretched film. Then, after drying, the film is stretched at least in a uniaxial direction and then subjected to heat treatment to complete the orientation of the thermoplastic resin film (so-called in-line coating method), or after the production of the thermoplastic resin film, A method of drying after applying a solvent-based coating solution (so-called off-line coating method) has been 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 thermoplastic resin 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. Has been.

JP 2000-141574 A Japanese Patent No. 3773738 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-mentioned problems, the present invention hardly deteriorates the coating layer in a high temperature and high humidity environment, which has been considered to be unavoidable in the past, in other words, almost no decrease in adhesion (moisture heat resistance) in a high temperature and high humidity environment. It is an object of the present invention to provide an easily-adhesive thermoplastic resin film that does not cause it.

  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 present inventor has not only initial adhesiveness but also moisture and heat resistance due to a coating layer containing a polycarbonate urethane resin and further containing a carbodiimide group of 0.5 to 3.5 mmol / g. As a result, the present inventors have found a surprising effect that the improvement is achieved. That is, while containing a polycarbonate-based urethane resin and a carbodiimide compound in the coating layer, these have substantially no cross-linked structure or have a low degree of cross-linking so that the carbodiimide group remains in the coating layer. Thus, the present inventors have found the fact of overcoming the conventional common sense that high adhesion is maintained even under high humidity, and have arrived at the present invention.

  As described in the above-mentioned patent document, in order to improve adhesion according to conventional technical common sense, a crosslinking agent and a resin having a functional group capable of reacting with it are mixed to form a highly crosslinked structure when the coating layer is laminated. It has been considered desirable. However, as a result of diligent research, the present inventor has found that a polycarbonate urethane resin and a carbodiimide cross-linking agent which have few or substantially no carboxyl groups or salts thereof, which are functional groups having high reactivity with carbodiimide groups. Easy-adhesive thermoplastic resin based on a new technical concept contrary to the prior art, in which initial adhesion and adhesion under wet heat are improved by forming a coating layer in which uncrosslinked carbodiimide groups remain in a specific range The film was obtained.

  That is, in the present invention, it is essential that the carbodiimide group remains in a specific range in the coating layer. A carbodiimide-based cross-linking agent having high reactivity with a carboxyl group is applied in combination with a resin having a functional group such as a carboxyl group from the technical common sense, and is combined with a resin having substantially no carboxyl group. There is no motivation to use, and it can be clearly distinguished from the prior art. In addition, content of the carbodiimide group in a coating layer can be calculated | required by a total reflection absorption infrared spectroscopy.

The present invention can be achieved by the following solutions. 1st invention of this application is an easily bonding thermoplastic resin film by which the coating layer was laminated | stacked on the at least single side | surface of the base film, Comprising: The said coating layer contains a polycarbonate-type urethane resin, Furthermore, the carbodiimide in the said coating layer It is an easily adhesive thermoplastic resin film containing 0.5 to 3.5 mmol / g of group.
2nd invention of this application is the said easily bonding thermoplastic resin film in which the said base film has a polyoxyalkylene group in the urethane resin.
3rd invention of this application is the said easily bonding thermoplastic resin film whose said carbodiimide compound is water-soluble and whose haze is 2.5% or less.
4th invention of this application is the said easily-adhesive thermoplastic resin film, Comprising: The said coating layer surface is selected from a hard-coat layer, a light-diffusion layer, a lens layer, an electromagnetic wave absorption layer, a near-infrared shielding layer, and a transparent conductive layer. An optically easy-adhesive thermoplastic resin film used by laminating at least one optical functional layer.

The easily adhesive thermoplastic resin film of the invention of the present application is very excellent in initial adhesion and adhesion under high temperature and high humidity (moisture heat resistance). As a preferred embodiment of the present invention, when the easy-adhesive thermoplastic resin film of the present invention is used as a base film for a diffusion plate or a lens sheet, the adhesiveness with an optical functional layer at high temperature and high humidity is excellent. In particular, the functional layer laminated on the coating layer, such as a lens sheet, has a very thin portion, and is particularly useful for applications where the coating layer is susceptible to deterioration under high temperature and high humidity.
Moreover, in the preferable aspect of this invention, it is excellent in initial adhesiveness and heat-and-moisture resistance, and can aim at coexistence with high transparency and handling property.

The present invention is described in detail below.
(Thermoplastic resin film)
The thermoplastic resin constituting the thermoplastic resin film used as a substrate in the present invention is a polyolefin resin such as polyethylene or polypropylene, a polyamide resin such as nylon 6 or nylon 66, polyethylene terephthalate, polybutylene terephthalate, polyethylene-2,6- As naphthalate, polymethylene terephthalate, and copolymer components, for example, diol components such as diethylene glycol, neopentyl glycol, polyalkylene glycol, adipic acid, sebacic acid, phthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, etc. A polyester resin copolymerized with a dicarboxylic acid component or the like can be used. Of these, polyester resins are preferred from the viewpoint of mechanical strength and chemical resistance.

  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 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 base film for an optical member, the total light transmittance of the easily adhesive thermoplastic resin film is preferably 85% or more, more preferably 87% or more, and 88% or more. More preferably, 89% or more is further 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 preferable to make a multilayer structure in which particles are contained only in the surface layer of the film, or to contain fine particles only in the coating layer without substantially containing particles in the film.

  In particular, from the viewpoint of transparency, when inert particles are practically not contained in the base film, inorganic and / or heat-resistant polymer particles are contained in the aqueous coating liquid in order to improve the handling properties of the film. It is 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.

Next, the coating layer of the present invention will be described.
(Coating layer)
It is important that the coating layer of the easy-adhesive thermoplastic resin film of the present invention contains a polycarbonate urethane resin and the carbodiimide group remains in a specific range. In the easy-adhesive thermoplastic resin film of the present invention, it is preferable that the polycarbonate polyurethane resin and the compound having a carbodiimide group have substantially no cross-linked structure or a low degree of cross-linking.

  Conventionally, it was considered desirable to positively introduce a crosslinked structure from the viewpoint of improving the heat and heat resistance of the coating layer as described above. However, the present inventor has found that the heat-and-moisture resistance is remarkably improved by configuring the coating layer as described above. 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.

  The coating layer of the present invention does not contain a carboxyl group or a salt thereof, which is a functional group having high reactivity with a carbodiimide group, or its salt is very small, so that there are many unreacted carbodiimide groups in the coating layer. . On the other hand, a functional group such as a carboxyl group is present in a resin used for a functional layer to be laminated, such as a photocurable acrylic resin and an unreacted product. Furthermore, a functional group exists also in the thermoplastic resin which is a base film. It is presumed that in a high-temperature and high-humidity environment, the interaction between the functional group and / or the carbodiimide group present in these functional layers and / or base film proceeds, and strong adhesion can be obtained.

  The lower limit of the carbodiimide group concentration in the coating layer in the present invention is 0.5 mmol / g, preferably 0.7 mmol / g, more preferably 1.0 mmol / g, and the upper limit is 3.5 mmol / g, preferably 3 0.3 mmol / g, more preferably 3.0 mmol / g. If the amount is less than the above lower limit, sufficient adhesiveness at high temperature and high humidity may not be obtained. When the above upper limit is exceeded, the ratio of the polycarbonate-based urethane resin becomes relatively small, and the adhesiveness, particularly the initial adhesiveness, may be lowered.

  In the present invention, according to the above-described embodiment, the adhesiveness (humidity and heat resistance) with an optical functional layer such as a lens layer, a hard coat layer, a light diffusion layer, an electromagnetic wave absorption layer, a near infrared ray blocking layer, and a transparent conductive layer under high temperature and high humidity Can be significantly improved. Further, the configuration of the present invention will be described in detail below.

The polycarbonate urethane resin used in the coating solution of the present invention will be described in more detail.
In this invention, it has a polycarbonate polyol as a structural component of a polycarbonate-type urethane resin, ie, a urethane resin, It is characterized by the above-mentioned.

  Urethane resins are broadly classified into polyester-based urethane resins, polyether-based urethane resins, and polycarbonate-based urethane resins. Polyester-based urethane resins are easily hydrolyzed at high temperatures and high humidity, and polyether-based urethane resins are highly hygroscopic. For this reason, the film strength of the coating layer tends to decrease, and the adhesion is insufficient. On the other hand, polycarbonate urethane resin has excellent moisture and heat resistance. This is the reason why the polycarbonate urethane resin is used in the present invention.

  That is, the moisture and 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 polycarbonate urethane resin of the present invention contains at least a polyol component and a polyisocyanate component as constituent components, and further contains a chain extender as necessary. The polycarbonate urethane resin of the present invention is a polymer compound in which these constituent components are mainly copolymerized by urethane bonds. In addition, the structural component of these polycarbonate-type urethane resins can be specified by nuclear magnetic resonance analysis (NMR) etc.

  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, 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 Polycarbonate diol obtained by reacting one or more diols such as bisphenol-A and 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 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, and isophorone diisocyanate. And alicyclic diisocyanates such as 4,4-dicyclohexylmethane diisocyanate and tetramethylxylylene diisocyanate, aliphatic diisocyanates such as hexamethylene diisocyanate and 2,2,4-trimethylhexamethylene diisocyanate, or a compound thereof. One or a plurality of polyisocyanates previously added with trimethylolpropane or the like can be mentioned.

  Examples of chain extenders include glycols such as ethylene glycol, diethylene glycol, 1,4-butanediol, and 1,6-hexanediol, polyhydric alcohols such as glycerin, trimethylolpropane, and pentaerythritol, ethylenediamine, and hexamethylene. Examples thereof include diamines and diamines such as piperazine, amino alcohols 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 the 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 particularly preferable 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 polycarbonate-based urethane resin obtained by the above method has substantially or little carboxyl groups or salts thereof which are functional groups with carbodiimide groups.

  The polycarbonate urethane resin is preferably contained in the coating layer in an amount of 30% by mass to 90% by mass. In particular, when high adhesion is required as in a lens layer, it is more preferably 40% by mass or more and 80% by mass or less. When the content of the urethane resin is large, the content of the carbodiimide compound is relatively small, so that the adhesiveness under high temperature and high humidity is reduced, and conversely, when the content of the urethane resin is small, Not only is the initial adhesion lowered, but the coating layer may be peeled off during the coating process, which may be a drawback.

  In the present invention, a resin other than the polycarbonate-based urethane resin may be contained for improving the adhesion. For example, an acrylic resin, a polyester resin, etc. are mentioned. Those having a low content of carboxyl groups or salts thereof are preferable, and those having no carboxyl group or salts thereof are more preferable. When there are many carboxyl groups or salts thereof, they react with carbodiimide groups, and carbodiimide groups that react with functional groups such as carboxyl groups contained in the base film or optical functional layer at high temperature and high humidity decrease. It is not preferable.

  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 tetramethylxylylene diisocyanate, 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 equivalent of the carbodiimide compound used in the present invention is not particularly limited, but specifically, for example, it is preferably 1000 or less, more preferably 500 or less, and even more preferably 300 or less. is there. When the said carbodiimide equivalent exceeds an upper limit, sufficient interaction with a carboxyl group etc. contained in a base film or a functional layer is not expressed, but durability and water resistance may not be obtained satisfactorily. In addition, the said carbodiimide equivalent shall be a chemical formula amount per 1 mol of carbodiimide groups. Therefore, the smaller the carbodiimide equivalent value, the larger the amount of carbodiimide groups in the polymer, and the larger the value, the smaller the amount of carbodiimide groups in the polymer.

  The carbodiimide compound is preferably contained in the coating layer in an amount of 10% by mass to 70% by mass. In particular, when high adhesion is required as in a lens layer, it is more preferably 30% by mass or more and 70% by mass or less. When the content of the carbodiimide compound is large, particularly the initial adhesion with the functional layer is lowered, and conversely, when the content is small, the adhesion under high temperature and high humidity is lowered.

  The presence or absence of carbodiimide groups in the coating layer and the content thereof can be determined by a known method. For example, a method of detecting by infrared spectroscopy as described below, or scraping off the coating layer, dissolving the scraped material in methyl ethyl ketone, chloroform or dimethylformamide, and using a nuclear magnetic resonance analyzer (NMR), from its integration ratio Examples thereof include a method of determining a mole% ratio of each composition.

  In the present invention, it is preferable to contain particles in the coating layer from the viewpoint of handling properties. The 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, 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.

  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 also preferably contained in a range that does not impair the adhesion to the optical functional layer, for example, in the range of 0.005 to 0.5% by mass in the coating solution.

  The easily adhesive thermoplastic resin film of the present invention preferably has a haze of 2.5% or less, more preferably 2.3% or less, and even more preferably 2.0% or less. Such an easily adhesive thermoplastic resin film can be improved in compatibility with other resins by suitably making the compound having a carbodiimide group 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, as a method of providing a coating layer on a substrate film, a method of coating and drying a coating solution containing a solvent, particles and a resin on the substrate film can be mentioned. 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 burden. preferable.

  Any known method can be used as a method for applying the coating liquid for forming the coating layer to the base 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 applying the coating solution to an unstretched or uniaxially stretched film, drying it, stretching it at least in a uniaxial direction, and then performing a heat treatment.

In this invention, it is preferable that the coating amount after drying of the coating layer finally obtained is 0.02-0.5 g / m < ² >. If the coating amount of the coating layer is less than 0.02 g / m ² , the effect on adhesiveness may be reduced. On the other hand, if the coating amount exceeds 0.5 g / m ² , blocking resistance may be lowered.

  The easy-adhesive thermoplastic resin film of the present invention is selected from a hard coat layer, a light diffusion layer, a lens layer, an electromagnetic wave absorption layer, a near-infrared shielding layer, and a transparent conductive layer on the coating layer surface of the base film described above. At least one optical function layer can be laminated and used. The shape of the lens layer is not particularly limited. For example, a prism-shaped lens, a Fresnel-shaped lens, a microlens, or the like can be suitably applied.

  The material used for the optical functional layer is not particularly limited, and a resin compound that is polymerized and / or reacted by drying, heat, chemical reaction, or irradiation with an electron beam, radiation, or ultraviolet light is used. be able to. Examples of such a curable resin include melamine-based, acrylic-based, silicon-based, and polyvinyl alcohol-based curable resins. However, in terms of obtaining high surface hardness or optical design, a photocurable acrylic curable resin is used. Resins are preferred. As such an acrylic curable resin, a polyfunctional (meth) acrylate monomer or an acrylate oligomer can be used. Examples of the acrylate oligomer include polyester acrylate, epoxy acrylate, urethane 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 and the like with these acrylic curable resins.

  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 Furthermore, 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) Quantitative determination of carbodiimide group concentration in coating layer The coating layer surface of the easy-adhesive polyester film obtained in Examples and Comparative Examples was measured by total reflection absorption infrared spectroscopy, and specifically obtained from the substrate film. The carbodiimide group concentration in the coating layer was determined using the obtained absorbance as a control.
That is, it is measured by total reflection absorption infrared spectroscopy under the conditions shown below to obtain an infrared absorption spectrum, and the ratio of the absorbance derived from carbodiimide to the absorbance of the substrate film (ethylene glycol in the case of PET film) (infrared absorbance) The ratio _A2120 / _A1340 ) was determined. The absorbance derived from the carbodiimide group is the value of the absorption peak height having an absorption maximum in the region of 2120 ± 10 cm ⁻¹ (A ₂₁₂₀ ), and the absorbance derived from PET has the absorption maximum in the region of 1340 ± 10 cm ^−1. The height of the absorption peak (A ₁₃₄₀ ) was used. The base line was a line connecting the sleeves on both sides of each maximum absorption peak.
The thickness of the coating layer was determined with a transmission electron microscope. A sample of an easily adhesive polyester film was embedded in a visible light curable resin (D-800, manufactured by Nippon Shin-EM Co., Ltd.) and cured by exposure to visible light at room temperature. From the obtained embedding block, an ultrathin section having a thickness of about 70 to 100 nm was prepared using an ultramicrotome equipped with a diamond knife, and dyed in ruthenium tetroxide vapor for 30 minutes. Furthermore, after performing carbon vapor deposition, the cross section was observed using the transmission electron microscope (the JEOL Co., Ltd. make, TEM2010), the photograph was image | photographed, and the thickness of the coating layer was measured from this. The photographing was appropriately set in the range of 10,000 to 100,000 times.
Based on the obtained infrared absorbance ratio A ₂₁₂₀ / A ₁₃₄₀ and the thickness of the coating layer, the carbodiimide group concentration in the coating layer was determined using a calibration curve prepared from a standard sample that had been coated in advance with a coating solution with a known carbodiimide concentration and air-dried. Asked.
In preparing the calibration curve, the coating solution with a carbodiimide group concentration of 0.5, 1.4, 2.7, 4.5 mmol / g (solvent: water / isopropyl alcohol = 1/1, with acrylic resin) The mixture was adjusted so that the fixed component concentration was 30% by mass), and the coating layer after drying was applied so that the thickness of the coating layer was 50 nm, 100 nm, and 200 nm. The infrared absorbance ratio A ₂₁₂₀ / A ₁₃₄₀ was measured by external spectroscopy, and the following primary formula consisting of three variables of carbodiimide group concentration, coating layer thickness, and infrared absorbance ratio A ₂₁₂₀ / A ₁₃₄₀ was obtained from the obtained results. This was used as a calibration curve.
(Carbodiimide concentration) = A × (infrared absorbance ratio A ₂₁₂₀ / A ₁₃₄₀ ) / (coating layer thickness) + B
(Here, A and B are constants obtained from the data obtained by creating the calibration curve)

(Measurement condition)
Apparatus: FTS-60A / 896 manufactured by Varian
Single reflection ATR attachment: Silver Gate manufactured by SPECTRA TECH
Optical crystal: Ge
Incident angle: 45 °
Resolution: 4cm ^-1
Cumulative number: 128 times If the coating layer is thin and sufficient sensitivity cannot be obtained, use a one-time reflection attachment with a larger incident angle (65 degrees) (for example, ST Japan Instead of VeeMax), the measurement may be performed.

(2) Initial adhesion The 3 micrometer photocurable acrylic layer was laminated | stacked on the surface of the obtained easily-adhesive polyester film application layer by the photocurable acrylic resin composition and hardening conditions shown below. 100 square cuts that penetrate the photocurable acrylic layer and reach the base film are made on the surface of the photocurable acrylic layer using a cutter guide having a gap interval of 2 mm. 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 film once, the number of squares peeled off from the photocurable acrylic layer surface of the laminated film was visually counted, and the following formula The adhesion between the photocurable acrylic layer and the base 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%

(Photo-curing acrylic resin composition)
About 5 g of the following photo-curing acrylic coating liquid is placed on a 1 mm thick SUS plate (SUS304) kept clean, and the film is applied so that the coating layer surface of the film sample and the photo-curing acrylic coating liquid are in contact with each other. The photo-curing acrylic coating solution was pressed from above the sample with a manually loaded rubber roller having a width of 10 cm and a diameter of 4 cm so as to extend. 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 (optical functional film).
(Photo-curing acrylic coating solution)
Photocurable acrylic resin 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)

(3) Moisture and heat resistance A laminated polyester film (optical functional film) obtained by laminating a photocurable acrylic resin obtained by the same method as in (2) above was heated at 80 ° C. and 95% RH in a high-temperature and high-humidity tank. It was left for 48 hours in the environment. Next, the optical functional 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 base film is improved in the same manner as in (2) except that the cellophane adhesive tape is peeled off from the photocurable acrylic layer surface of the optical functional film vertically five times. The ranking was based on the following criteria.
A: 100%, or material breakage of photocurable acrylic layer B: 99-90%
Δ: 89-70%
X: 69 to 0%

(4) 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. .

(5) Haze Based on JIS-K7105, it evaluated using the integrating-sphere type light transmittance measuring apparatus (made by Nippon Denshoku Industries Co., Ltd.).

(6) Carbodiimide value The carbodiimide compound was freeze-dried and analyzed by ¹ H-NMR, and the carbodiimide value was calculated from the absorption peak intensity derived from the carbodiimide group and the absorption peak intensity derived from other monomers.

(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-1) with a solid content of 35% was prepared by removing a portion of acetonitrile and water under reduced pressure.

(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-2) 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-3) to (A-4) 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 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)
A flask equipped with a thermometer, a nitrogen gas inlet tube, a reflux condenser, a dropping funnel, and a stirrer was mixed with 200 parts by mass of tetramethylxylylene diisocyanate and carbodiimidization catalyst 3-methyl-1-phenyl-2-phospholene-1-oxide 4 parts by mass was added and stirred at 180 ° C. for 40 hours under a nitrogen atmosphere to obtain isocyanate-terminated tetramethylxylylene carbodiimide (degree of polymerization = 5). Next, 94.5 g of the obtained carbodiimide and 40.0 g of polyethylene glycol monomethyl ether (molecular weight 220) 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. The carbodiimide equivalent was 246.

(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 12 hours under a nitrogen atmosphere to obtain an isocyanate-terminated isophorone carbodiimide (degree of polymerization = 6). Next, 129.2 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-2) having a solid content of 40% by mass. The carbodiimide equivalent was 349.

(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 10 hours in a nitrogen atmosphere to obtain isocyanate-terminated 4,4-dicyclohexylmethane (degree of polymerization = 4). Next, 113.6 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-3) having a solid content of 40% by mass. The carbodiimide equivalent was 484.

(Polymerization of water-dispersible carbodiimide compound)
A flask equipped with a thermometer, a nitrogen gas inlet tube, a reflux condenser, a dropping funnel, and a stirrer was mixed with 200 parts by mass of tetramethylxylylene diisocyanate and carbodiimidization catalyst 3-methyl-1-phenyl-2-phospholene-1-oxide 4 parts by mass was added and stirred at 180 ° C. for 40 hours in a nitrogen atmosphere to obtain isocyanate-terminated tetramethylxylylene carbodiimide (degree of polymerization = 10). Next, 169.7 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 water-dispersible carbodiimide compound (B-4) having a solid content of 40% by mass. The carbodiimide equivalent was 250.

Example 1
(1) Adjustment of coating liquid The following coating agent was mixed and the coating liquid was created.
Water 53.66% by mass
Isopropanol 30.00% by mass
Polyurethane resin (A-1) 11.28 mass%
Water-soluble carbodiimide compound (B-1) 4.23 mass%
Particles 0.71% by mass
(Silica sol with an average particle size of 40 nm, solid content concentration of 40% by mass)
0.07% 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 thermoplastic resin film having a thickness of 100 μm. The evaluation results are shown in Table 2.

Comparative Example 1
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 53.26% by mass
Isopropanol 30.00% by mass
Polyurethane resin (A-1) 14.50 mass%
Water-soluble carbodiimide compound (B-1) 1.41% by mass
Particles 0.71% by mass
(Silica sol with an average particle size of 40 nm, solid content concentration of 40% by mass)
0.07% 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)

Comparative Example 2
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 54.96 mass%
Isopropanol 30.00% by mass
Polyurethane resin (A-1) 0.81% by mass
Water-soluble carbodiimide compound (B-1) 13.40 mass%
Particles 0.71% by mass
(Silica sol with an average particle size of 40 nm, solid content concentration of 40% by mass)
0.07% 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)

Comparative 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-5) containing polyester polyol as a constituent component.

Comparative Example 4
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 5
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 6
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 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 53.46% by mass
Isopropanol 30.00% by mass
Polyurethane resin (A-1) 12.89 mass%
Water-soluble carbodiimide compound (B-1) 2.82% by mass
Particles 0.71% by mass
(Silica sol with an average particle size of 40 nm, solid content concentration of 40% by mass)
0.07% 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 3
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 54.26% by mass
Isopropanol 30.00% by mass
Polyurethane resin (A-1) 6.45% by mass
Water-soluble carbodiimide compound (B-1) 8.46% by mass
Particles 0.71% by mass
(Silica sol with an average particle size of 40 nm, solid content concentration 40% by mass)
0.07% 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 4
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 54.47% by mass
Isopropanol 30.00% by mass
Polyurethane resin (A-1) 4.83% by mass
Water-soluble carbodiimide compound (B-1) 9.87 mass%
Particles 0.71% by mass
(Silica sol with an average particle size of 40 nm, solid content concentration of 40% by mass)
0.07% 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 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-soluble carbodiimide compound (B-2).

Example 6
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).

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 polyurethane resin (A-1) was changed to the polyurethane resin (A-2).

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 polyurethane resin (A-1) was changed to the polyurethane resin (A-3).

Example 9
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 (A-1) was changed to the polyurethane resin (A-4).

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-dispersible carbodiimide compound (B-4).

  The easy-adhesive thermoplastic resin film of the present invention is excellent in initial adhesion and wet heat resistance. In particular, since it has excellent initial adhesion to the optical functional layer and heat and heat resistance, it is mainly used in displays and the like, and is used as a hard coat film, an antireflection film using the film, a light diffusion sheet, a prismatic lens sheet, and a near infrared shielding film. It is suitable as a base film for optical functional films such as transparent conductive films and antiglare films.

Claims (4)

An easily adhesive thermoplastic resin film in which a coating layer is laminated on at least one side of a base film,
The coating layer contains a polycarbonate-based urethane resin,
Furthermore, the easily adhesive thermoplastic resin film which contains 0.5-3.5 mmol / g of carbodiimide groups in the said application layer.   The easily adhesive thermoplastic resin film according to claim 1, wherein the urethane resin has a polyoxyalkylene group.   The easily adhesive thermoplastic resin film according to claim 1 or 2, wherein the carbodiimide compound is water-soluble and has a haze of 2.5% or less.   From the hard coat layer, the light diffusion layer, the prismatic lens layer, the electromagnetic wave absorption layer, the near infrared ray blocking layer, and the transparent conductive layer to the coating layer of the easily adhesive thermoplastic resin film according to any one of claims 1 to 3. An optically easy-adhesive thermoplastic resin film obtained by laminating at least one selected functional layer.