JP5544884B2 - Easy-adhesive thermoplastic film - Google Patents

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 film.

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

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

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

  For example, by providing a coating layer containing various resins such as polyester, acrylic, polyurethane, and acrylic graft polyester on the surface of the thermoplastic resin film of the base material as the main component of the coating layer, the base film can be easily adhered. The method of giving 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. The 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 functional film used as a member also needs to maintain adhesion 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 has been considered to be an easily-adhesive thermoplastic resin that has been considered to be unavoidable in the past, and that hardly causes deterioration of the coating layer under high temperature and high humidity, in other words, almost no decrease in adhesion under high temperature and high humidity. A film is provided.

  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-mentioned problems, the present inventor has a polyester resin having a specific molecular weight, and further has only an initial adhesion by a coating layer containing 0.5 to 3.5 mmol / g of oxazoline groups. The inventors have found a surprising effect that the heat and humidity resistance is improved, and have reached the present invention. That is, the coating layer contains a polyester resin having a specific molecular weight and an oxazoline compound, but these have substantially no cross-linked structure or have a low degree of cross-linking so that oxazoline groups remain in the coating layer. Thus, the present inventors have found a fact that overturns the conventional common sense that high adhesion is maintained even under high temperature and high humidity, and have led to the present invention.

  As described in the above-mentioned patent documents, 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 is a new technology contrary to the prior art, in which adhesion is improved under high temperature and high humidity by using a polyester resin that has substantially no carboxylic acid group that is a functional group that reacts with an oxazoline group. It is an easily adhesive film based on the idea.

  That is, in the present invention, it is essential that the oxazoline group remains in a specific range in the coating layer. An oxazoline-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. The content of the oxazoline group in the coating layer can be determined by total reflection absorption infrared spectroscopy.

The above-described problem can be achieved by the following solution means. (1) An easily adhesive thermoplastic resin film 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 An easily-adhesive thermoplastic resin film containing a resin and further containing 0.5 to 3.5 mmol / g of oxazoline group in the coating layer.
(2) The easily adhesive thermoplastic resin film, wherein the polyester resin contains a dicarboxylic acid component represented by the following formula (1) and / or a diol component represented by the following formula (2).
(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)
(3) The easy-adhesive thermoplastic resin film comprising naphthalenedicarboxylic acid as an acid component of the polyester resin.
(4) The easily adhesive thermoplastic resin film in which the resin having an oxazoline group is water-soluble (5) A hard coat layer, a light diffusing layer, and a prismatic lens layer are formed on the coating layer of the easily adhesive thermoplastic resin film. A laminated thermoplastic resin film obtained by laminating at least one functional layer selected from an electromagnetic wave absorbing layer, a near infrared ray blocking layer, and a transparent conductive layer.

The easily-adhesive thermoplastic resin film of the present invention is excellent in adhesion (humidity heat resistance) and initial adhesion under high temperature and high humidity with the functional layer. Therefore, as a preferred embodiment, the adhesion at the high temperature and high humidity treatment is equal to or improved from the initial adhesion. As a preferred embodiment of the present invention, when the easily adhesive thermoplastic resin film of the present invention is used as a base material for a hard coat, the adhesion with the hard coat layer under high temperature and high humidity is good.
Furthermore, in a preferred embodiment of the present invention, optical interference fringes are suppressed and the visibility is excellent.

(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 substrate film for an optical member, the total light transmittance of the easily adhesive polyester film is preferably 85% or more, more preferably 87% or more, and even more preferably 88% or more. 89% or more is more preferable, and 90% or more is particularly preferable.

  For high definition, the content of inert particles in the base film is preferably as small as possible. Therefore, it is 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 an inert particle is practically not contained in the polyester film, an inorganic and / or heat-resistant polymer particle is contained in the aqueous coating solution in order to improve the handleability of the film. It is 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.

  It is also a preferable aspect that the base film of the present invention contains inorganic particles in order to improve handling properties. A preferred embodiment of the base film is a base film composed of at least three layers. As the layer structure in the three-layer structure, the structure of the outermost layer on the front and back may be the same composition or different composition, but the two kinds of three layers (A layer / B layer / A layer) are flat. From the point of view, it is preferable.

  In the case of a three-layer structure, it is preferable that the outermost layer (A layer / B layer / A layer in the case of A layer) contains particles and the center layer (B layer) contains substantially no particles. The reason why the layer A contains particles is that the contact area between the base film and the coating layer interface can be increased by setting the surface roughness to an appropriate level, and an effect of obtaining higher adhesion can be obtained. This is to improve handling properties such as slipping property, winding property and blocking resistance, and wear properties such as wear resistance and scratch resistance. The characteristics can be evaluated by a coefficient of static friction (μs) between the laminated film surfaces. In this case, the static friction coefficient (μs) is preferably 0.7 or less. The reason why the layer B does not substantially contain particles is to maintain high transparency.

  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. The lower limit of the average particle diameter is more preferably 0.5 μm, further preferably 0.8 μm, and still more preferably 1.0 μm. Further, the upper limit of the average particle is more preferably 3.0 μm, still more preferably 2.8 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.

  These particles are preferably porous particles, particularly porous silica. Porous particles are easily deformed into a flat shape during stretching in the film forming process, and voids are not easily generated around the particles during stretching, and high transparency is easily obtained.

  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. The lower limit of the concentration is more preferably 0.02% by mass, and further preferably 0.03% by mass. Further, the upper limit of the concentration is more preferably 0.15% by mass, and further preferably 0.10% by mass. If it is less than the lower limit, sufficient handling properties cannot be obtained. When the upper limit is exceeded, the transparency decreases.

The average particle size of the particles can be measured by the following method.
The particles are photographed with an electron microscope or an optical microscope, and the maximum diameter of 300-500 particles (in the case of porous silica, the aggregate size) is such that the size of one smallest particle is 2-5 mm. Particle diameter) is measured, and the average value is defined as the average particle diameter. Moreover, when calculating | requiring the average particle diameter of the particle | grains in the application layer of a laminated film, the cross section of a laminated film is image | photographed by 120,000 times magnification using a transmission electron microscope (TEM), and it exists in the cross section of an application layer. The maximum diameter of the particles can be determined.

  As a method of blending the particles with the polyester resin, a known method can be adopted. For example, it can be added at any stage for producing the polyester, but it is preferably added as a slurry dispersed in ethylene glycol or the like at the stage of esterification or after the end of the ester exchange reaction and before the start of the polycondensation reaction. The polycondensation reaction may proceed. Also, a method of blending a slurry of particles dispersed in ethylene glycol or water with a vented kneading extruder and a polyester raw material, or a method of blending dried particles and a polyester raw material using a kneading extruder It can be carried out.

  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 a polyester resin having at least a number average molecular weight of 15000 or more and substantially having no carboxylic acid group, and further containing 0.5 to 3. oxazoline group in the coating layer. It is important to provide a coating layer containing 5 mmol / g.

  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 is substantially free of carboxylic acid groups that are functional groups that react with oxazoline groups, unreacted oxazoline groups remain in the coating layer when the coating layer is formed. On the other hand, under high temperature and high humidity, the polyester resin in the coating layer undergoes hydrolysis, the ester bond is broken, and carboxylic acid group terminals are generated. Here, the unreacted oxazoline group reacts with the generated carboxylic acid terminal to form a crosslink. In other words, it is considered that the deterioration of the coating film strength under high temperature and high humidity can be prevented by self-healing the deterioration of the coating film strength due to hydrolysis.

  In the present invention, the lower limit of the concentration of the oxazoline group in the coating layer 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 upper limit is exceeded, the ratio of the polyester resin becomes relatively small, and the adhesion, particularly the initial adhesion, 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 coating layer of the present invention needs to contain a polyester resin. Adhesion can be improved by containing a polyester resin.

  The polyester resin preferably has fewer carboxylic acid groups which are reactive groups with oxazoline 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 the oxazoline 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, the number average molecular weight is preferably 60000 or less because the solubility in the coating solution may be reduced as the number average molecular weight increases.

  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, it is preferable to 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. 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.

  In order to set the number average molecular weight of the polyester resin to 15000 or more and to have a glass transition temperature enough to suppress blocking, 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 3 or more carboxyl groups / one molecule or 3 or more hydroxyl groups / 1 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 to 85% by mass. When high adhesiveness is required, it is more preferably 20% by mass or more and 80% 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 decreases.

  In this invention, in order to improve adhesiveness, you may contain other than a polyester resin. Examples of such a resin include an acrylic resin and a urethane resin. 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 an oxazoline group, and the oxazoline group which reacts with the carboxylic acid group generated from a polyester resin under high temperature and high humidity will decrease.

  In the present invention, it is necessary to contain a resin having an oxazoline group. Examples of the resin having an oxazoline group include water dispersibility and water solubility. The resin having an oxazoline group is preferably water-soluble because it has good compatibility with other water-soluble resins and improves the transparency of the coating layer and the crosslinking reaction efficiency. The above water-soluble means to dissolve in water or an aqueous solution containing less than 50% by mass of a water-soluble organic solvent.

  In order to make the resin having an oxazoline group water-soluble, it is preferable to contain a hydrophilic monomer. As the hydrophilic monomer, a monomer having a polyethylene glycol chain such as 2-hydroxyethyl (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, a monoester compound of (meth) acrylic acid and polyethylene glycol, (Meth) acrylic acid 2-aminoethyl and its salts, (meth) acrylamide, N-methylol (meth) acrylamide, N- (2-hydroxyethyl) (meth) acrylamide, (meth) acrylonitrile, sodium styrenesulfonate, etc. Can be mentioned. Especially, it is preferable to contain the monomer which has polyethyleneglycol chains, such as (meth) acrylic-acid methoxypolyethylene glycol with high solubility to water, and the monoester compound of (meth) acrylic acid and polyethyleneglycol.

  Further, the oxazoline value of the resin having an oxazoline group used in the present invention is not particularly limited, but specifically, for example, 1000 g-solid / eq. Or less, more preferably 500 g-solid / eq. Hereinafter, even more preferably, 300 g-solid / eq. It is as follows. When the said oxazoline value exceeds an upper limit, interaction with the carboxyl group etc. which are included in a sufficient base film or a functional layer is not expressed, and durability and water resistance may not be obtained satisfactorily. The oxazoline value (g-solid / eq.) Is assumed to be a polymer weight per 1 mol of the oxazoline group. Therefore, the smaller the value of the oxazoline value, the larger the amount of oxazoline groups in the polymer, and the larger the value, the smaller the amount of oxazoline groups in the polymer.

  The resin having an oxazoline group is preferably contained in the coating layer in an amount of 5% by mass to 90% by mass. In particular, when high adhesion is required as in a lens layer, it is more preferably 10% by mass or more and 70% by mass or less. When the content of the resin having an oxazoline group is large, the adhesion with the optical functional layer is lowered, and conversely, when the content is small, the carboxylic acid group generated from the polyester resin under high temperature and high humidity Since the reacting oxazoline group is reduced, the restoration function of the coating film is lowered, and the adhesiveness is lowered.

  In the present invention, in order to improve the coating film strength, the coating layer may contain a crosslinking agent different from the resin having an oxazoline group or a resin having a crosslinking group. Examples of the crosslinking agent include urea, epoxy, melamine, 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, satin white, aluminum silicate, diatomaceous earth Inorganic particles such as soil, 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, phenol, di Rirufutareto systems include organic particles of polyester or the like.

  The average particle diameter of the particles is not particularly limited, but from the viewpoint of maintaining the transparency of the film, the average particle diameter of the particles is preferably 1 to 500 nm, and more preferably 1 to 100 nm. The average particle diameter is an average particle diameter measured by using a Coulter Counter (manufactured by Beckman Coulter, Multisizer II type) dispersed in a solvent that does not swell.

  Two or more kinds of particles having different average particle diameters may be used as the particles.

  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 functional layer.

  The easily adhesive thermoplastic resin film of the present invention preferably has a haze of 3.0% or less, more preferably 2.5% 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 an oxazoline 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, examples of the method of providing the coating layer on the thermoplastic resin film include a method of coating and drying a coating liquid containing a solvent, particles and resin on the polyester film. Examples of the solvent include organic solvents such as toluene, water, and a mixed system of water and a water-soluble organic solvent. Preferably, water alone or a mixture of a water-soluble organic solvent and water is used from the viewpoint of environmental problems. preferable.

  The laminated thermoplastic resin film of the present invention comprises 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 on at least one surface of the above-mentioned thermoplastic resin film coating layer. It is obtained by at least one selected nobility layer.

  The material used for the functional layer is not particularly limited.

(Manufacture of easy-adhesive thermoplastic resin film)
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.

  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 functional layers mainly for optical use, it is possible to provide a laminated thermoplastic resin film that can maintain an initial function for a long time even under high temperature and high humidity. 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) Glass transition temperature In accordance with JIS K7121, using a differential scanning calorimeter (Seiko Instruments, DSC6200), 10 mg of the resin sample was heated at a rate of 20 ° C / min over a temperature range of 25 to 300 ° C, and DSC The extrapolated glass transition start temperature obtained from the curve was defined as the glass transition temperature.

(3) Number average molecular weight 0.03 g of resin was dissolved in 10 ml of tetrahydrofuran, and a 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).

(4) 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.

(5) 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.

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

(7) Oxazoline value A resin having an oxazoline group is freeze-dried and analyzed by ¹ H-NMR, and the oxazoline value is calculated from the absorption peak intensity derived from the oxazoline group and the absorption peak intensity derived from other monomers. did.

(8) Quantification of oxazoline 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 base film. The oxazoline 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 oxazoline to the absorbance of the substrate film (ethylene glycol in the case of PET film) (infrared absorbance) The ratio A ₁₆₅₅ / A ₁₃₄₀ ) was determined. The absorbance derived from the oxazoline group is the height of the absorption peak having an absorption maximum in the region of 1655 ± 10 cm ⁻¹ (A ₁₆₅₅ ), 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 easy-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 ₁₆₅₅ / A ₁₃₄₀ and the thickness of the coating layer, the concentration of the oxazoline group in the coating layer was determined using a calibration curve prepared from a standard sample that had been coated with a coating solution with a known oxazoline concentration and air-dried in advance. Asked.
In preparing the calibration curve, the coating solution (solvent: water / isopropyl alcohol = 1/1, acrylic resin with the oxazoline group concentration of 0.5, 1.4, 2.7, 4.5 mmol / g) 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. Infrared absorbance ratio A ₁₆₅₅ / A ₁₃₄₀ was measured by external spectroscopy, and the following primary formula consisting of three variables of oxazoline group concentration, coating layer thickness, infrared absorbance ratio A ₁₆₅₅ / A ₁₃₄₀ was obtained from the obtained results. This was used as a calibration curve.
(Oxazoline concentration) = A × (Infrared absorbance ratio A ₁₆₅₅ / 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.

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

(10) Moisture and heat resistance The obtained laminated polyester film was allowed to stand in an environment of 80 ° C. and 95% RH for 48 hours in a high-temperature and high-humidity tank. Next, the laminated polyester film was taken out and allowed to stand at room temperature and humidity for 12 hours. Thereafter, the adhesiveness between the photocurable acrylic layer and the substrate film is the same as in (9) above except that the cellophane adhesive tape is peeled off from the photocurable acrylic layer surface of the laminated polyester film five times. Was ranked according to the following criteria.
A: 100%, or material breakage of photocurable acrylic layer B: 99-90%
Δ: 89-70%
X: 69 to 0%

(11) Interference spot improvement (iris color)
The obtained laminated polyester 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. For example, ◎ and ○ are 2 people each and △ is 1 person, ○ is ◎, ◎ is 1 person and ○ and △ are 2 people each, ○, ◎ and △ are 2 people each and ○ is 1 In the case of names, ○ is adopted.
○: Mostly iris-like colors can be seen Δ: Slightly iris-like colors are observed ×: Clear iris-like colors are observed

(12) Handling property A sample film was prepared by cutting into an area of 8 cm × 5 cm from the films obtained in Examples and Comparative Examples. This was fixed to the bottom surface of a metal rectangular parallelepiped having a size of 6 cm × 5 cm and having a weight of 4.4 kg so that the coating layer surface was on the outside. At this time, the 5 cm width direction of the sample film and the 5 cm width direction of the metal cuboid were matched, one side in the longitudinal direction of the sample film was bent, and fixed to the side surface of the metal cuboid with an adhesive tape.
Next, a sample film was cut out in the area of 20 cm × 10 cm from the same film, and the end portion in the longitudinal direction was fixed to a flat metal plate with the adhesive layer surface side facing up with an adhesive tape. The measurement surface of the metal rectangular parallelepiped on which the sample film was adhered was placed in contact with this, and the static friction coefficient (μs) was measured under the conditions of a pulling speed of 200 mm / min, 23 ° C. and 65% RH. For the measurement, RTM-100 manufactured by Toyo BALDWIN was used, and the coefficient of static friction (μs) was calculated according to JIS K-7125.
When the static friction coefficient (μs) was 0.7 or less, handling property was good (◯), and when it exceeded 0.7, handling property was poor (x).

(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., and the pressure of the reaction system was gradually reduced, followed by reaction for 1 hour 30 minutes under a reduced pressure of 30 Pa to obtain a copolymerized polyester resin (A-1). The obtained copolyester resin (A-1) was light yellow and transparent. It was 0.70 dl / g when the reduced viscosity of the obtained copolyester resin (A-1) was measured. The glass transition temperature by DSC was 40 ° C.

In the same manner, copolymer polyester resins (A-2) to (A-7) having different compositions were obtained. Table 1 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 (A-1) and 15 parts by mass of ethylene glycol n-butyl ether were placed in a reactor equipped with a stirrer, a thermometer and a reflux device, and heated 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 (B-1) having a solid content of 30% by mass. Similarly, using the polyester resins (A-2) to (A-7) instead of the polyester resin (A-1), water dispersions were prepared, and the water dispersions (B-2) to (B- 7).

(Synthesis of water-soluble resin having oxazoline group)
A flask equipped with a stirrer, a reflux condenser, a nitrogen inlet tube and a thermometer was charged with 460.6 parts of isopropyl alcohol and heated to 80 ° C. while gently flowing nitrogen gas. A monomer mixture consisting of 126 parts of methyl methacrylate, 210 parts of 2-isopropenyl-2-oxazoline and 84 parts of methoxypolyethylene glycol acrylate prepared in advance, and ABN-E (manufactured by Nippon Hydrazine Kogyo Co., Ltd.) Polymerization initiator: An initiator solution consisting of 21 parts of 2,2′-azobis (2-methylbutyronitrile) and 189 parts of isopropyl alcohol was added dropwise over 2 hours using a dropping funnel. During the reaction, nitrogen gas was kept flowing, and the temperature in the flask was kept at 80 ± 1 ° C. After the completion of dropping, the temperature was kept at the same temperature for 5 hours and then cooled. The water-soluble resin (C-1) which adjusted with ion-exchange water and has an oxazoline group with a solid content concentration of 25 mass% was obtained. The oxazoline value is 220 g-solid / eq. Met.

(Synthesis of resin having oxazoline group)
A glass reactor equipped with a thermometer, a stirrer, a nitrogen inlet tube, and a reflux condenser was charged with 100 parts of polyethylene glycol monomethyl ether having an average molecular weight of 500 and heated to 140 ° C. under a nitrogen stream. Next, while maintaining the temperature in the glass reactor at 140 to 142 ° C., 50 parts of butyl acrylate, 50 parts of 2-isopropenyl-2-oxazoline and 10 parts of di-tert-butyl peroxide are separately added. It was dripped continuously over 2 hours. After completion of dropping, the mixture was stirred while maintaining at 140 to 142 ° C for 2 hours, 0.5 part of di-tert-butyl peroxide was added, and then further stirred while maintaining at 140 to 142 ° C for 1.5 hours. The water-soluble resin (C-2) which adjusted with ion-exchange water and has an oxazoline group with a solid content concentration of 25 mass% was obtained. The oxazoline value is 440 g-solid / eq. Met.

(Synthesis of resin having oxazoline group)
A flask equipped with a stirrer, a reflux condenser, a nitrogen inlet tube and a thermometer was charged with 460.6 parts of isopropyl alcohol and heated to 80 ° C. while gently flowing nitrogen gas. A monomer mixture consisting of 213 parts of methyl methacrylate, 58 parts of 2-isopropenyl-2-oxazoline and 123 parts of methoxypolyethylene glycol acrylate prepared in advance, and ABN-E (manufactured by Nippon Hydrazine Kogyo Co., Ltd.) Polymerization initiator: An initiator solution consisting of 21 parts of 2,2′-azobis (2-methylbutyronitrile) and 189 parts of isopropyl alcohol was added dropwise over 2 hours using a dropping funnel. During the reaction, nitrogen gas was kept flowing, and the temperature in the flask was kept at 80 ± 1 ° C. After the completion of dropping, the temperature was kept at the same temperature for 5 hours and then cooled. The water-soluble resin (C-3) which adjusted with ion-exchange water and has an oxazoline group with a solid content concentration of 25 mass% was obtained. The oxazoline value is 550 g-solid / eq. Met.

Example 1
(1) Adjustment of coating liquid The following coating agent was mixed and the coating liquid was created. The polyester resin has a number average molecular weight of 20000.
Water 49.24% by mass
Isopropanol 30.00% by mass
Polyester aqueous dispersion (B-1) 13.16% by mass
Water-soluble resin (C-1) having an oxazoline group 6.77 mass particles 0.71 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) Manufacture of easy-adhesive polyester film Intrinsic viscosity 0.62 (phenol: 1,1,2,2-tetrachloroethane = 6: 4 dissolved in a mixed solvent) not containing particles as a raw material for an intermediate layer of a base film The PET (A) measured at 30 ° C. was dried under reduced pressure (1 Torr) at 135 ° C. for 6 hours, and then the pelletized PET (A) and the intrinsic viscosity were 0.62 in the extruder 2 (for the intermediate layer B layer). (Phenol: 1,1,2,2-tetrachloroethane = 6: 4 dissolved in a mixed solvent and measured at 30 ° C.), and PET containing 0.025% by mass of silica particles having an average particle diameter of 2.5 μm ( B) was supplied to the extruder 1 (for the outer layer A layer) and melted at 285 ° C. These two polyester resins are filtered through a filter medium made of a sintered stainless steel (nominal filtration accuracy of 10 μm particles, 95% cut), laminated in a three-layer confluence block, extruded into a sheet form from a die, and then electrostatically The film was wound around a casting drum having a surface temperature of 30 ° C. using an applied casting method, and solidified by cooling to obtain an unstretched film. At this time, the discharge amount of each extruder was adjusted so that the ratio of the thicknesses of the A layer, the B layer, and the A layer was 1.5: 7: 1.5. Next, this unstretched film 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 peripheral speed difference to obtain a uniaxially oriented 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 100 degreeC for 5 second (s). In addition, it adjusted so that the application quantity after the last (after biaxial stretching) drying might be set to 0.1 g / m < ² >. Next, this uniaxially stretched polyester film was guided to a clip-type transverse stretching machine, preheated at 100 ° C., stretched 4.0 times in the transverse direction at 130 ° C., then heat-set at 230 ° C., and then at 150 ° C. After 3% relaxation treatment in the transverse direction, the film was wound with a film winder to obtain an easily adhesive polyester film having a thickness of 250 μm.
The evaluation results are shown in Table 2.

(3) Manufacture of laminated polyester film A coating liquid for forming a hard coat layer (C-1) having the following composition was applied to the coating layer surface of the easy-adhesive polyester film using a # 10 wire bar, and 1 at 70 ° C. Dry for minutes to remove the solvent. Next, the film coated with the hard coat layer was irradiated with 300 mJ / cm ² ultraviolet rays using a high-pressure mercury lamp to obtain a laminated polyester film having a hard coat layer with 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 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 49.99 mass%
Isopropanol 30.00% by mass
Polyester water dispersion (B-1) 16.92 mass%
Water-soluble resin having oxazoline group (C-1) 2.26% 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 46.80 mass%
Isopropanol 30.00% by mass
Polyester aqueous dispersion (B-1) 0.94% by mass
Water-soluble resin (C-1) having an oxazoline group 21.43% 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 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 (B-6) 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 (B-7) having an acid value of 50 KOHmg / g.

Comparative Example 5
An easily-adhesive polyester film and a laminate as in Example 1 except that the water-soluble resin (C-1) having an oxazoline group is changed to an epoxy compound (Denacol EX-521, solid content concentration: 100%, manufactured by Nagase ChemteX Corporation). A polyester film was obtained.

Comparative Example 6
An easily-adhesive polyester film and a laminated polyester film in the same manner as in Example 1 except that the water-soluble resin (C-1) having an oxazoline group is changed to a melamine compound (Becamine M-3 solid content concentration: 60% by DIC). Got.

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 49.62% by mass
Isopropanol 30.00% by mass
Polyester water dispersion (B-1) 15.04 mass%
Water-soluble resin (C-1) having an oxazoline group 4.51% 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.
48.11% by mass of water
Isopropanol 30.00% by mass
Polyester water dispersion (B-1) 7.52 mass%
Water-soluble resin having oxazoline group (C-1) 13.54% 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 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 47.74% by mass
Isopropanol 30.00% by mass
Polyester water dispersion (B-1) 5.64% by mass
Water-soluble resin (C-1) having an oxazoline group 15.79% 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 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 resin (C-1) having an oxazoline group was changed to the water-soluble resin (C-2) having an oxazoline group.

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 resin (C-1) having an oxazoline group was changed to the water-soluble resin (C-3) having an oxazoline group.

Example 7
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 (B-2) having a molecular weight of 15000.

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

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 polyester water dispersion was changed to a polyester water dispersion (B-4) having a molecular weight of 46000.

Example 10
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 (B-5) having a molecular weight of 50000.

Example 11
Example 1 except that the water-soluble resin (C-1) having an oxazoline group was changed to Nippon Shokubai Epocross K-2010E (water dispersibility, solid content concentration 40 mass%, oxazoline value 550 g-solid / eq). Thus, an easily adhesive polyester film and a laminated polyester film were obtained.

Example 12
The intrinsic viscosity of the pelletized PET for layer A is 0.62 (dissolved in a mixed solvent of phenol: 1,1,2,2-tetrachloroethane = 6: 4 and measured at 30 ° C.), and the average particle size is 2. Easy-adhesive polyester film and laminated polyester film in the same manner as in Example 1 except that PET (C) containing 0.035% by mass of silica particles of 5 μm was supplied to the extruder 1 (for outer layer A layer). Got.

Example 13
The intrinsic viscosity of the pelletized PET for layer A is 0.62 (dissolved in a mixed solvent of phenol: 1,1,2,2-tetrachloroethane = 6: 4 and measured at 30 ° C.), and the average particle size is 2. Easy-adhesive polyester film and laminated polyester film in the same manner as in Example 1 except that PET (C) containing 0.010% by mass of 5 μm silica particles was supplied to the extruder 1 (for outer layer A layer). Got.

Example 14
The pellet-like PET for layer A has an intrinsic viscosity of 0.62 (dissolved in a mixed solvent of phenol: 1,1,2,2-tetrachloroethane = 6: 4 and measured at 30 ° C.), and an average particle size of 1. Easy-adhesive polyester film and laminated polyester film in the same manner as in Example 1 except that PET (C) containing 0.025% by mass of 4 μm silica particles was supplied to the extruder 1 (for outer layer A layer). Got.

Example 15
In the same manner as in Example 1 except that PET (B) containing 0.025% by mass of silica particles having an average particle diameter of 2.5 μm for the B layer was used as the raw material polymer without providing the A layer. An easily adhesive polyester film and a laminated polyester film were obtained.

Example 16
In Example 1, except that the A layer was not provided and the polyethylene terephthalate (PET) resin pellet having an intrinsic viscosity of 0.62 dl / g and not containing particles for the B layer was used as the raw material polymer. 1 was used to obtain a laminated film.

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

Claims (5)

An easily adhesive thermoplastic resin film having a coating layer on at least one surface of the thermoplastic resin film,
The coating layer contains a polyester resin having a number average molecular weight of 20000 or more and an acid value of 3 KOHmg / g or less ,
Furthermore, the said coating layer contains 10 mass% or more of resin which has an oxazoline group, The easily adhesive thermoplastic resin film which contains 0.5-3.5 mmol / g of oxazoline groups in the said coating layer. The easily adhesive thermoplastic resin film according to claim 1, wherein the polyester resin contains a dicarboxylic acid component represented by the following formula (1) and / or a diol component represented by the following formula (2). .
(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 easy-adhesive thermoplastic resin film according to claim 1, wherein naphthalenedicarboxylic acid is included as an acid component of the polyester resin. Highly adhesive thermoplastic resin film according to claim 1 resin having an oxazoline group is water-soluble. The coating layer of highly adhesive thermoplastic resin film according to claim 1, a hard coat layer, the light diffusion layer, prismatic lens layer, electromagnetic wave absorbing layer, a near infrared ray blocking layer, a transparent conductive A laminated thermoplastic resin film obtained by laminating at least one functional layer selected from layers.