JP2011152783A - Easily bondable thermoplastic resin film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an easily bondable thermoplastic resin film excelling in blocking resistance and, in adhesiveness to an optical function layer under high temperature and high humidity. <P>SOLUTION: The easily bondable thermoplastic resin film has a coating layer on at least one surface of a thermoplastic resin film. The coating layer contains: polyester resin having number average molecular weight of 15,000 or more and substantially having no carboxylic acid group; and polyurethane resin containing polycarbonate polyol as a component, and further containing a carbodiimide compound. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an easily-adhesive thermoplastic resin film excellent in adhesion and moisture and heat 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 thermoplastic resin film.

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

  When using the thermoplastic resin film as a base material for various 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 that it is very scarce. For this reason, methods for imparting easy adhesion to the biaxially oriented thermoplastic resin film surface by various methods have been 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 obtained by dispersing the resin in a dispersion medium is coated on a thermoplastic resin film before completion of crystal orientation, and dried. Thereafter, 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, the film is water-based or solvent-based. A method of drying after applying a 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. In a laminated film used for such applications, high adhesion is required 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 by forming a crosslinked structure in the coating layer resin at the time of forming the coating layer by the in-line coating method by adding a crosslinking agent to the coating solution. Is disclosed.

  For example, in Patent Document 1, one kind of resin selected from an acrylic resin, a polyester resin, and a urethane resin in the laminated film, and a melamine-based crosslinking agent, an oxazoline-based crosslinking agent, an isocyanate-based crosslinking agent, an aziridine-based crosslinking agent, Alternatively, for a lens sheet that includes a cross-linking agent selected from at least one of epoxy-based cross-linking agents and is provided with a laminated film containing at least one of amide ester bond, urethane bond, amide bond, and urea bond A film is disclosed, and specifically, urethane resin and melamine crosslinking agent, polyester resin and melamine crosslinking agent and oxazoline crosslinking agent, acrylic resin, polyester resin and oxazoline crosslinking agent and the like are exemplified.

  Patent Document 2 exemplifies an optically easily adhesive polyester film provided with a coating layer containing a polyester resin and an acrylic resin having an oxazoline group and a polyalkylene oxide chain.

  Patent Document 3 exemplifies an easily adhesive film in which a polyester-based polyurethane and an oxazoline-containing polymer are applied.

  Patent Document 4 exemplifies a polycarbonate-based polyurethane having an anionic group and a melamine-based crosslinking agent or an epoxy-based crosslinking agent.

  In addition, in the patent document 5, the present applicant exemplifies an easily adhesive film for optics in which a coating layer made of a copolyester resin, a polyurethane resin, and an oxazoline-based crosslinking agent is laminated.

JP 2000-141574 A Japanese Patent No. 3773738 JP 2000-355086 A Japanese Patent No. 2544792 Japanese Patent No. 3900191

  Longer life expectancy is expected for home appliances with a display to reduce the global environmental impact. Therefore, it was considered necessary to maintain adhesion for a long period of time even in a high temperature and high humidity environment. However, although the easy-adhesion film as disclosed in the above-mentioned patent document shows good adhesion at first in a wet and heat environment, a decrease in adhesion strength is unavoidable in long-term use. Due to such a decrease in adhesion, there is a problem that the initial performance is not maintained for a long time.

  Furthermore, in order to improve the adhesion between the functional layer and the substrate film, a method of using a resin having a low glass transition temperature as the resin constituting the coating layer is common. However, when a resin having a low glass transition temperature is used, the blocking resistance tends to decrease when the film is continuously wound into a roll and the film is unwound from the roll. In recent years, in order to reduce the cost, the size of a processing machine for laminating functional layers such as a hard coat layer and a diffusion layer on a base film has been increased, and a roll of an easily adhesive film used as a base film. The diameter is also increasing. Along with this, when winding with high tension in order to prevent roll misalignment, blocking is more likely to occur because the core of the roll is pressure-bonded with high pressure. For this reason, the demand for improved blocking resistance has become stronger, but there has also been a problem that blocking resistance is reduced when the adhesion is improved.

  In view of the above-mentioned problems, the present invention hardly deteriorates the coating layer in a wet heat environment that has been considered to be unavoidable in the past, in other words, hardly causes a decrease in adhesion under a wet heat environment, and is excellent in blocking resistance. An easily adhesive thermoplastic resin film can be provided.

  The adhesion at high temperature and high humidity in the present invention is a cutter having a clearance of 2 mm after laminating a photocurable acrylic layer or hard coat layer and placing it in an environment of 80 ° C., 95% RH, 48 hours. Using a guide, 100 square cuts that penetrate the photocurable acrylic layer or hard coat layer and reach the base film are made on the surface of the photocurable acrylic layer or hard coat layer, and then the cellophane adhesive tape is applied to the grid. It is affixed to a cut surface in the shape of an object, rubbed with an eraser, and completely adhered, meaning the adhesiveness when the same part is vigorously peeled five times, and is generally used as an evaluation method described in JIS K5600-5-6 It means adhesion in stricter judgment criteria, and the present invention shows that the adhesion under such high temperature and high humidity is equivalent to or higher than the adhesion shown in the initial stage. It is a challenge.

In addition, the blocking resistance as used in the present invention is specifically the two coating layer surfaces of the film samples overlapped with each other, and a pressure of 1 kgf / cm ² was adhered thereto in an atmosphere of 50 ° C. for 24 hours. Thereafter, the film is peeled off, and the peeled state means “a thing that can be lightly peeled without any transfer of the coating layer”.

  As a result of intensive studies to solve the above problems, the present inventor provided a coating layer containing a polyester resin having a specific molecular weight, a polyurethane resin containing polycarbonate polyol as a constituent component, and further containing a carbodiimide compound. As a result, the present inventors have found the fact that the conventional technical common sense that adhesion and blocking resistance are improved under high temperature and high humidity has led to the present invention.

  As described in the above-mentioned patent document, in order to improve the adhesion of the coating layer in the conventional technical common sense, it is mixed with a crosslinking agent and a resin having a functional group capable of reacting with it, and a highly crosslinked structure is formed when the coating layer is formed. It has been considered desirable to form. However, the present invention uses a polyester resin and a polyurethane resin that have substantially no carboxylic acid group that is a functional group that reacts with a carbodiimide group, thereby improving adhesion at high temperatures and high humidity. It is an easy-adhesion film based on a new technical idea.

  In addition, in order to improve the blocking resistance, a method of providing irregularities on the film surface and reducing the contact area by incorporating particles in the coating layer or the base film has been generally employed. . However, this method causes a decrease in the light transmittance of the film and an increase in haze. Thus, as a result of intensive studies, the present inventor has found that the anti-blocking property is improved by combining specific resins, and has reached the present invention.

The above-described problem can be achieved by the following solution means.
(1) A highly adhesive thermoplastic resin having a coating layer on at least one surface of a thermoplastic resin film, wherein the coating layer has a number average molecular weight of 15000 or more and has substantially no carboxylic acid group. And an easily adhesive thermoplastic resin film containing a polyurethane resin containing polycarbonate polyol as a constituent component and further containing a carbodiimide compound.
(2) The easily adhesive thermoplastic resin film, wherein the urethane resin has a polyoxyethylene group.
(3) The easy-adhesive thermoplastic resin film in which the carbodiimide compound is water-soluble and has a haze of 2.0% or less. (4) A hard coat layer, light, and a coating layer on the easy-adhesive thermoplastic resin film. An optical laminated thermoplastic resin film having at least one optical functional layer selected from a diffusion layer, a prismatic lens layer, an electromagnetic wave absorption layer, a near infrared ray blocking layer, and a transparent conductive layer.

  The easy-adhesive thermoplastic resin film of the present invention is excellent in adhesion (humidity heat resistance) 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. Moreover, since the easily adhesive thermoplastic resin film of this invention is excellent in blocking resistance, it can respond to the enlargement of a film roll diameter. As a preferred embodiment of the present invention, when the easily adhesive thermoplastic resin film of the present invention is used as a substrate for a lens sheet, the adhesion with the lens layer under heat and humidity resistance is good.

(Thermoplastic resin film)
The thermoplastic resin constituting the thermoplastic resin film used as the 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. Polyester resins such as those obtained by copolymerizing 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 film slipperiness, rollability and blocking resistance, and wear characteristics such as abrasion resistance and scratch resistance, inert particles may be included in the base film. . However, since 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 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 more preferably 88% or more. Preferably, 89% or more is even 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, when used for optical applications, from the viewpoint of transparency, inorganic and / or heat-resistant polymer particles are used in order to improve the handleability of the film when the inert film is not substantially contained in the base film. Is preferably contained in the aqueous coating solution 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)
The easy-adhesive film of the present invention contains at least a polyester resin having a number average molecular weight of 15000 or more and having substantially no carboxylic acid group, a polyurethane resin containing polycarbonate polyol as a constituent component, and a carbodiimide compound. It is important to provide a coating layer.

  Conventionally, it has been considered desirable to positively introduce a crosslinked structure from the viewpoint of improving the heat and moisture resistance of the coating layer. However, in this invention, it discovered that heat-and-moisture resistance improved by making a coating layer into the above structures. 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.

  Since the coating layer of the present invention has few or substantially no carboxylic acid group, which is a functional group that reacts with carbodiimide groups, unreacted carbodiimide groups remain in the coating layer when the coating layer is formed. On the other hand, in a high-temperature and high-humidity environment, the polyester resin constituting the coating layer or the base material is hydrolyzed, ester bonds are broken, and carboxylic acid group terminals are 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, we believe that self-healing can prevent a decrease in adhesion due to hydrolysis. Furthermore, in this invention, the more excellent heat-and-moisture resistance can be exhibited by using the polycarbonate-type urethane resin excellent in durability. Moreover, in this invention, coating film hardness can be improved by using a polyester resin, and the outstanding blocking resistance can be exhibited simultaneously with adhesiveness. In addition, since these resins have little or substantially no carboxylic acid group that is a functional group that reacts with the oxazoline group, the oxazoline group can be suitably left in the coating layer.

  According to the above aspect, the present invention can improve adhesion (humidity heat resistance) with a lens layer, a hard coat layer, and another optical functional layer under high temperature and high humidity. 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 carboxylic acid 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 80% by mass. In particular, when high adhesion is required, such as a lens layer and a hard coat layer, the content is more preferably 20% by mass or more and 70% 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.

(Polyester resin)
The coating layer of the present invention needs to contain a polyester resin. By containing the polyester resin, the adhesion to the base film and the blocking resistance can be improved.

  The polyester resin preferably has fewer carboxylic acid groups that are reactive groups with carbodiimide groups. More preferably, it has substantially no carboxylic acid group. Here, having substantially no carboxylic group means that it contains no carboxylic acid group other than the terminal group. As a method for defining a carboxylic acid group, an acid value can be measured. However, the polyester resin having substantially no carboxylic acid group has an acid value of 3 KOHmg / g or less, more preferably 2 KOHmg / g or less. More preferably, it is a polyester resin of 1 KOHmg / g or less.

  The number average molecular weight of the polyester resin needs to be 15000 or more. When the number average molecular weight is low, the terminal carboxylic acid group increases, which may cause a reaction with a carbodiimide group. In addition, the hydrolysis is accelerated, the coating film is not sufficiently repaired, and not only the adhesiveness under high temperature and high humidity is not obtained, but also the adhesiveness with the substrate film is lowered. Further, the number average molecular weight is more preferably 20000 or more, and it is preferably higher as long as it can be produced. However, when the number average molecular weight is increased, the solubility in the coating solution may be lowered. Therefore, the lower limit of the number average molecular weight is preferably 30000 or less.

The polyester resin has acid components such as terephthalic acid, isophthalic acid, phthalic acid, phthalic anhydride, 2,6-naphthalenedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, adipic acid, sebacic acid, trimellitic acid, pyromellitic acid, Examples include dimer acid, 5-sodium sulfoisophthalic acid, 4-sodium sulfonaphthalene-2,7-dicarboxylic acid, and the like. Examples of the diol component include ethylene glycol, propane glycol, 1,4-butanediol, neopentyl glycol, diethylene glycol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, xylene glycol, ethylene oxide adduct of bisphenol A, etc. Is mentioned. When a hard coat layer mainly made of an acrylic resin is provided on the film of the present invention, interference fringes are generated due to the difference in refractive index between the coating layer and the other layer, which may cause a problem in terms of visibility. For this reason, it is preferable to contain naphthalenedicarboxylic acid capable of obtaining a higher refractive index as an acid component because it improves the heat and moisture resistance and the effect of suppressing iris-like colors.

Moreover, from the point of suppression of the iris-like color at the time of providing a hard-coat layer, it may contain the dicarboxylic acid component of following formula (1) and / or the diol component of following formula (2) as a component of a polyester resin. preferable. The dicarboxylic acid component of the following formula (1) and / or the diol component of the following formula (2) in the polyester resin is preferably 10% or more, more preferably 15% or more, and further preferably 20% or more. Further, the dicarboxylic acid component of the following formula (1) and / or the diol component of the following formula (2) in the polyester resin is preferably 70% or less, more preferably 60% or less, and further preferably 50% or less. When exceeding the said upper limit, a coating film may become soft too much and heat-and-moisture resistance may fall. When it is less than the above lower limit, the flexibility of the polyester resin is lowered, the coating film becomes too hard, and the adhesion may be lowered.
(1) HOOC- (CH ₂ ) _n —COOH (where n is an integer of 4 ≦ n ≦ 10)
(2) HO— (CH ₂ ) _n —OH (where n is an integer of 4 ≦ n ≦ 10)

  The polyester resin is based on water or a water-soluble organic solvent (for example, an aqueous solution containing less than 50% by weight of alcohol, alkyl cellosolve, ketone, or ether) or an organic solvent (for example, toluene, ethyl acetate, etc.). Those dissolved or dispersed can be used.

  When the polyester resin is used as an aqueous coating liquid, a water-soluble or water-dispersible polyester resin is used. For such water-solubilization or water-dispersion, a compound containing a sulfonate group or a carboxyl group is used. It is preferable to copolymerize a compound containing an acid base. Therefore, in addition to the dicarboxylic acid component described above, in order to impart water dispersibility to the polyester, it is preferable to use 5-sulfoisophthalic acid or an alkali metal salt thereof in the range of 1 to 10 mol%. Mention may be made of acid, 5-sulfoisophthalic acid, 4-sulfonaphthaleneisophthalic acid-2,7-dicarboxylic acid and 5- (4-sulfophenoxy) isophthalic acid or alkali metal salts thereof.

  The polyester resin preferably has a low glass transition temperature from the viewpoint of adhesion, but preferably has a high glass transition temperature from the viewpoint of blocking resistance. Therefore, the glass transition temperature of the polyester resin is preferably 10 to 100 ° C, and more preferably 30 to 70 ° C. When the glass transition temperature is higher than 100 ° C., the melt viscosity becomes high, and it is difficult to obtain a product having a sufficient molecular weight, so that the adhesiveness is lowered. When the glass transition temperature is lower than 10 ° C., the blocking resistance of the film is lowered.

  In order to set the number average molecular weight of the polyester resin to 15000 or more and make the glass transition temperature in the above range, it is preferable to introduce a branched structure into the polyester resin. However, as the number of branched structures increases, the acid value tends to increase. Therefore, in the polyester resin of the present invention, the molar ratio of the third component having three or more carboxyl groups / one molecule or three or more hydroxyl groups / one molecule is 5.0 mol% or less in the total dicarboxylic acid component. Preferably, it is 1.0 mol% or less more preferably.

  The polyester resin is preferably contained in the coating layer in an amount of 10% by mass to 80% by mass. When high adhesiveness is required, it is more preferably 20% by mass or more and 70% by mass or less. When the content of the polyester resin is large, the adhesiveness under high temperature and high humidity decreases, and conversely, when the content is small, the adhesiveness with the base film and the blocking resistance are decreased.

  In the present invention, a resin other than a polyurethane resin and a polyester resin may be contained in order to improve adhesion. For example, an acrylic 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 generate | occur | produced from a polyester resin under high temperature and high humidity will reduce.

(Carbodiimide compound)
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 3% by mass to 45% by mass. In particular, when high adhesion is required, such as a lens layer and a hard coat layer, the content is more preferably 5% by mass or more and 40% by mass or less. When the content of the carbodiimide compound is large, the adhesion with the optical 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, oxazoline, isocyanate, and silanol. 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 Inorganic particles such as white, aluminum silicate, diatomaceous earth, calcium silicate, aluminum hydroxide, hydrous halloysite, magnesium carbonate, magnesium hydroxide, (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-based, phenol-based, 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 preferably contained in the coating layer within a range that does not impair the adhesion to the optical functional layer.

  The easy-adhesive thermoplastic resin film of the present invention preferably has a haze value of 2.0% or less, more preferably 1.5% or less. Such an easily adhesive thermoplastic resin 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 optical 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 problems. preferable.

  The optical laminated film of the present invention has a hard coat layer, a light diffusing layer, a prismatic lens layer, an electromagnetic wave absorbing layer, a near-infrared blocking layer, a transparent conductive material, on at least one surface of the coating layer of the above-mentioned easily adhesive thermoplastic resin film. It is obtained by at least one optical functional layer selected from the layers.

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

(Manufacture of easily adhesive polyester film for optics)
Although the production method of the easily adhesive thermoplastic resin film of the present invention will be described by taking a polyethylene terephthalate (hereinafter abbreviated as PET) film as an example, it is naturally not limited thereto.

  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) Reduced viscosity It measured at 30 degreeC using 25 mL of mixed solvents of phenol (60 mass%) and 1,1,2,2-tetrachloroethane (40 mass%) as a solvent with respect to 0.1 g of resin.

(3) Glass transition temperature In accordance with JIS K7121, using a differential scanning calorimeter (Seiko Instruments, DSC6200), 10 mg of a resin sample was heated at a rate of 20 ° C / min over a temperature range of 25 to 300 ° C. The extrapolated glass transition start temperature obtained from the curve was defined as the glass transition temperature.

(4) Number average molecular weight 0.03 g of resin was dissolved in 10 ml of tetrahydrofuran, and GPC-LALLS apparatus low-angle light scattering photometer LS-8000 (manufactured by Tosoh Corporation, tetrahydrofuran solvent, reference: polystyrene) was used at a column temperature of 30 ° C. The number average molecular weight was measured using a flow rate of 1 ml / min and a column (showex KF-802, 804, 806 manufactured by Showa Denko KK).

(5) Resin composition The resin is dissolved in deuterated chloroform, and ¹ H-NMR analysis is performed using a nuclear magnetic resonance analyzer (NMR) Gemini-200 manufactured by Varian, and the mol% ratio of each composition is determined from the integral ratio. Were determined.

(6) Acid value 1 g (solid content) of a sample was dissolved in 30 ml of chloroform or dimethylformamide, and titrated with 0.1 N potassium hydroxide ethanol solution using phenolphthalein as an indicator to determine the carboxyl groups per gram of the sample. The amount (mg) of KOH required for neutralization was determined.

(7) Total light transmittance of easy-adhesive thermoplastic resin film The total light transmittance of the obtained easy-adhesive thermoplastic resin film is based on JIS K 7105, and a turbidimeter (Nippon Denshoku, NDH2000) is used. And measured.

(8) Haze of easy-adhesive thermoplastic resin film The haze of the obtained easy-adhesive thermoplastic resin film was measured using a turbidimeter (Nippon Denshoku, NDH2000) according to JIS K7136.

(9) Adhesiveness 100 masses reaching the base film through the photocurable acrylic layer using a cutter guide with a gap interval of 2 mm on the photocurable acrylic layer or hard coat layer surface of the laminated film. Make eye-shaped cuts. 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 or hard coat layer surface of the laminated film was visually counted. The adhesion between the photocurable acrylic layer or hard coat layer and the substrate film was determined from the following formula. 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
◎: 100%, or material breakage of photocurable acrylic layer or hard coat layer ○: 99-90%
Δ: 89-70%
X: 69 to 0%

(10) Heat-and-moisture resistance The obtained laminated film was left in an environment of 80 ° C. and 95% RH for 48 hours in a high-temperature and high-humidity tank. Next, the laminated film was taken out and left at room temperature and normal humidity for 12 hours. Thereafter, except that the cellophane adhesive tape is peeled off from the surface of the light curable acrylic layer or hard coat layer of the laminated film vertically five times, the photo curable acrylic layer or hard coat layer and The contact adhesion of the substrate film was determined and ranked according to the following criteria.
◎: 100%, or material breakage of photocurable acrylic layer or hard coat layer ○: 99-90%
Δ: 89-70%
X: 69 to 0%

(11) Blocking resistance The coating layer surfaces of two film samples were overlapped, and a pressure of 1 kgf / cm ² was adhered thereto in an atmosphere of 50 ° C. for 24 hours, and then peeled. Judged by criteria.
○: The coating layer is not transferred and can be peeled lightly. Δ: A peeling sound is generated and the coating layer is partially transferred to the mating surface. ×: The two films are fixed and cannot be peeled or peeled. Even if the base film is cleaved

(12) Interference spot improvement (iris color)
The obtained hard coat film was cut into an area of 10 cm (film width direction) × 15 cm (film longitudinal direction) to prepare a sample film. A black glossy tape (manufactured by Nitto Denko, vinyl tape No. 21; black) was attached to the surface of the obtained sample film opposite to the hard coat layer. This sample film has a hard coat surface as the top surface and a three-wavelength daylight white color (National Palook, FL 15EX-N 15W) as a light source. 60 cm, and an angle of 15 to 45 ° with respect to the perpendicular to the film surface).

The results of visual observation are ranked according to the following criteria. The observation is performed by five people who are familiar with the evaluation, and the highest rank is the evaluation rank. If two ranks have the same number, the center of the rank divided into three is adopted.
○: Almost no iris color is seen △: Slightly iris color is observed ×: Clear iris color is observed

(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 polyoxyethylene 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.

  A polyurethane resin (A-5) having a polyoxyethylene group was obtained in the same manner except that the polyisocyanate of the polyurethane resin (A-4) was changed to isophorone diisocyanate.

(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-6) 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-7) having a solid content of 35%.

(Polyester resin polymerization)
In a stainless steel autoclave equipped with a stirrer, a thermometer, and a partial reflux condenser, 194.2 parts by weight of dimethyl terephthalate, 184.5 parts by weight of dimethyl isophthalate, 14.8 parts by weight of dimethyl-5-sodium sulfoisophthalate, 233.5 parts by mass of diethylene glycol, 136.6 parts by mass of ethylene glycol, and 0.2 parts by mass of tetra-n-butyl titanate were charged, and a transesterification reaction was performed from 160 ° C. to 220 ° C. over 4 hours. Next, the temperature was raised to 255 ° C., the pressure of the reaction system was gradually reduced, and the mixture was reacted for 1 hour 30 minutes under a reduced pressure of 30 Pa to obtain a copolymerized polyester resin (B-1). The obtained copolyester resin (B-1) was light yellow and transparent. It was 0.70 dl / g when the reduced viscosity of the obtained copolyester resin (B-1) was measured. The glass transition temperature by DSC was 40 ° C.

In the same manner, copolymer polyester resins (B-2) to (B-5) having different compositions were obtained. Table 2 shows the composition (mole% ratio) and other characteristics measured by ¹ H-NMR for these copolymer polyester resins.

(Adjustment of polyester aqueous dispersion)
30 parts by mass of polyester resin (B-1) and 15 parts by mass of ethylene glycol n-butyl ether were put into a reactor equipped with a stirrer, a thermometer and a reflux device, and heated and stirred at 110 ° C. to dissolve the resin. After the resin was completely dissolved, 55 parts by mass of water was gradually added to the polyester solution while stirring. After the addition, the solution was cooled to room temperature while stirring to prepare a milky white polyester aqueous dispersion (C-1) having a solid content of 30% by mass. Similarly, using the polyester resins (B-2) to (B-7) instead of the polyester resin (B-1), water dispersions were prepared, and the water dispersions (C-2) to (C- 7).

(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 (D-1) 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 (D-2) was obtained.

(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 (D-3) 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 (D-4) having a solid content of 40% by mass.

Example 1
(1) Adjustment of coating liquid The following coating agent was mixed and the coating liquid was created.
Water 52.65% by mass
Isopropanol 30.00% by mass
Polyester resin (C-2) 7.15% by mass
Polyurethane resin (A-4) 6.95% by mass
Water-soluble carbodiimide compound (D-1) 1.35% by mass
1.35% by mass of particles
(Silica sol with an average particle size of 40 nm, solid content concentration of 40% by mass)
0.54% by mass of particles
(Silica sol with an average particle size of 450 nm, solid content concentration of 40% 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 3.

(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 solution Photo-curing acrylic resin 60.00% by mass
(Shin Nakamura Chemical 4G)
Photo-curing acrylic resin 20.00% by mass
(Shin-Nakamura Chemical A-TMMT)
Photo-curing acrylic resin 10.00% by mass
(Shin-Nakamura Chemical A-BPE-4)
Photo-curing acrylic resin 8.00% by mass
(Shin Nakamura Chemical U-6HA)
Photopolymerization initiator 2.00% by mass
(Irgacure 184 manufactured by Ciba Specialty Chemicals)

(4) Production of hard coat film A hard coat layer-forming coating solution having the following composition was applied to the coating layer surface of the above-mentioned easy-adhesive polyester film using a # 10 wire bar, and dried at 70 ° C. for 1 minute. Was removed. Next, the film coated with the hard coat layer was irradiated with 300 mJ / cm ² of ultraviolet light using a high pressure mercury lamp to obtain a hard coat film having a thickness of 5 μm.
Hard coat layer forming coating liquid methyl ethyl ketone 39.00% by mass
Toluene 26.00% by mass
Dipentaerythritol hexaacrylate 22.83 mass%
(Shin-Nakamura Chemical A-DPH)
Polyethylene diacrylate 11.17% by mass
(Shin-Nakamura Chemical A-400)
Photopolymerization initiator 1.00% 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-6) 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-7) containing polyether polyol as a constituent component.

Comparative 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 polyester water dispersion was changed to a polyester water dispersion (C-4) having a molecular weight of 8000.

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 polyester aqueous dispersion was changed to a polyester aqueous dispersion (C-5) having an acid value of 50 KOHmg / g.

Comparative Example 5
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 53.15% by mass
Isopropanol 30.00% by mass
Polyurethane resin (A-4) 11.58 mass%
Water-soluble carbodiimide compound (D-1) 3.38% by mass
1.35% by mass of particles
(Silica sol with an average particle size of 40 nm, solid content concentration of 40% by mass)
0.54% by mass of particles
(Silica sol with an average particle size of 450 nm, solid content concentration of 40% by mass)

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 coating solution was changed to the following.
Water 52.81 mass%
Isopropanol 30.00% by mass
Polyester resin (C-2) 11.92 mass%
Water-soluble carbodiimide compound (D-1) 3.38% by mass
1.35% by mass of particles
(Silica sol with an average particle size of 40 nm, solid content concentration of 40% by mass)
0.54% by mass of particles
(Silica sol with an average particle size of 450 nm, solid content concentration of 40% by mass)

Comparative 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 was changed to a polyurethane resin (A-1) containing polycarbonate polyol as a constituent component.

Comparative Example 8
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.

Comparative 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 was changed to a polyurethane resin (A-3) containing polycarbonate polyol as a constituent component.

Comparative Example 10
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 (D-1) was changed to an epoxy compound (Denacol EX-521, solid content concentration 100%, manufactured by Nagase ChemteX Corporation). Obtained.

Comparative Example 11
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 (D-1) was changed to a melamine compound (Becamine M-3 solid content concentration: 60% 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 polyester water dispersion was changed to a polyester water dispersion (C-1) having a molecular weight of 20000.

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 polyester water dispersion was changed to a polyester water dispersion (C-3) having a molecular weight of 23000.

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.
52.54% by mass of water
Isopropanol 30.00% by mass
Polyester resin (C-2) 7.55 mass%
Polyurethane resin (A-4) 7.34% by mass
Water-soluble carbodiimide compound (D-1) 0.68 mass%
1.35% by mass of particles
(Silica sol with an average particle size of 40 nm, solid content concentration of 40% by mass)
0.54% by mass of particles
(Silica sol with an average particle size of 450 nm, solid content concentration of 40% by mass)

Example 5
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 52.87% by mass
Isopropanol 30.00% by mass
Polyester resin (C-2) 6.36 mass%
Polyurethane resin (A-4) 6.18% by mass
Water-soluble carbodiimide compound (D-1) 2.70% by mass
1.35% by mass of particles
(Silica sol with an average particle size of 40 nm, solid content concentration of 40% by mass)
0.54% by mass of particles
(Silica sol with an average particle size of 450 nm, solid content concentration of 40% by mass)

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 53.08 mass%
Isopropanol 30.00% by mass
Polyester resin (C-2) 5.56 mass%
Polyurethane resin (A-4) 5.41% by mass
Water-soluble carbodiimide compound (D-1) 4.05 mass%
1.35% by mass of particles
(Silica sol with an average particle size of 40 nm, solid content concentration of 40% by mass)
0.54% by mass of particles
(Silica sol with an average particle size of 450 nm, solid content concentration of 40% 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.
52.56% by mass of water
Isopropanol 30.00% by mass
Polyester resin (C-2) 10.33 mass%
Polyurethane resin (A-4) 3.86% by mass
Water-soluble carbodiimide compound (D-1) 1.35% by mass
1.35% by mass of particles
(Silica sol with an average particle size of 40 nm, solid content concentration of 40% by mass)
0.54% by mass of particles
(Silica sol with an average particle size of 450 nm, solid content concentration of 40% 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 52.74% by mass
Isopropanol 30.00% by mass
Polyester resin (C-2) 3.97 mass%
Polyurethane resin (A-4) 10.04% by mass
Water-soluble carbodiimide compound (D-1) 1.35% by mass
1.35% by mass of particles
(Silica sol with an average particle size of 40 nm, solid content concentration of 40% by mass)
0.54% by mass of particles
(Silica sol with an average particle size of 450 nm, solid content concentration of 40% by mass)

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 was changed to a urethane resin (A-5) having a polyoxyethylene group with polycarbonate polyol as a constituent component.

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 (D-1) was changed to the water-dispersible carbodiimide compound (D-2).

Example 11
An easy-adhesive polyester film and a laminated polyester film were obtained in the same manner as in Example 7 except that the polyester water dispersion was changed to a polyester water dispersion (C-6) having a molecular weight of 45,000.

Example 12
An easily adhesive polyester film and a laminated polyester film were obtained in the same manner as in Example 7 except that the polyester aqueous dispersion was changed to a polyester aqueous dispersion (C-7) having a molecular weight of 46000.

Example 13
An easily adhesive polyester film and a laminated polyester film were obtained in the same manner as in Example 5 except that the water-soluble carbodiimide compound (D-1) was changed to the water-dispersible carbodiimide compound (D-3).

Example 14
An easily adhesive polyester film and a laminated polyester film were obtained in the same manner as in Example 5 except that the water-soluble carbodiimide compound (D-1) was changed to the water-dispersible carbodiimide compound (D-4).

  Since the laminated thermoplastic resin film of the present invention is excellent in adhesion with the optical functional layer and adhesion under high temperature and high humidity (moisture and heat resistance), a hard coat film mainly used for displays and the like are used. It is suitable as a base film for optical functional films such as an antireflection film, a light diffusion sheet, a prismatic lens sheet, a near-infrared shielding film, a transparent conductive film, and an antiglare film.

Claims (4)

An easily adhesive thermoplastic resin having a coating layer on at least one side of the thermoplastic resin film,
The coating layer includes a polyester resin having a number average molecular weight of 15000 or more and substantially having no carboxylic acid group, and a polyurethane resin having a polycarbonate polyol as a constituent component,
Furthermore, an easily adhesive thermoplastic resin film containing a carbodiimide compound.   The easily adhesive thermoplastic resin film according to claim 1, wherein the urethane resin has a polyoxyethylene group.   The easily adhesive thermoplastic resin film according to claim 1, wherein the carbodiimide compound is water-soluble and has a haze of 2.0% or less.   The coating layer of the easy-adhesive thermoplastic resin film according to claim 1, at least 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. An optical laminated thermoplastic resin film having one optical functional layer.