JP6737364B2 - Laminated polyester film - Google Patents

Description

The present invention relates to an easily-adhesive polyester film that can ensure low interference that can solve the problem of rainbow unevenness and that has excellent transparency. More specifically, the present invention relates to an easily-adhesive polyester film that has few fine scratches and can be suitably used even in high-definition optical applications.

A hard coat film in which a transparent hard coat layer is laminated is used on the front surface of a display such as a touch panel, a computer, a television, a liquid crystal display device, and a decorative material. A transparent polyester film is generally used as the transparent plastic film of the base material, and in order to improve the adhesion between the polyester film of the base material and the hard coat layer, easy adhesion is provided as an intermediate layer between them. In many cases, a coating layer having the same is provided.

The hard coat film is required to have resistance to temperature, humidity and light, transparency, chemical resistance, scratch resistance, antifouling property and the like. In addition, since it is often used on the surface of displays and decorative materials, visibility and designability are required. Therefore, in order to suppress glare and iris color due to reflected light when viewed from an arbitrary angle, the antireflection of a multilayer structure in which a high refractive index layer and a low refractive index layer are laminated on top of the hard coat layer. It is common practice to provide layers.

However, in applications such as displays and decorative materials, in recent years, further larger screens (larger areas) and higher resolutions have been demanded, and accordingly, there has been a demand for suppression of iris-like colors (interference spots) particularly under fluorescent lamps. The level is getting higher. In addition, the three-wavelength type of fluorescent lamps has become the mainstream due to the reproducibility of daylight color, and interference spots are more likely to occur. Furthermore, there is an increasing demand for cost reduction by simplifying the antireflection layer. Therefore, there is a demand for a hard coat film that does not have an antireflection layer alone to suppress interference spots as much as possible.

The iris-like color (interference spots) of the hard coat film is the same as the refractive index of the polyester film of the base material (for example, 1.62 to 1.65) and the refractive index of the hard coat layer made of an acrylic resin (for example, 1.49). It is said that this occurs because the difference between the two is large. In order to reduce the difference in refractive index between laminated layers and prevent the occurrence of interference spots, a coating layer is provided on the polyester film of the base material, the refractive index difference between the polyester film and the coating layer, and the refraction between the coating layer and the hard coat layer. A method is disclosed in which the refractive index of the coating layer is controlled by the contents of the resin constituting the coating layer and the high-refractive-index additive so as to reduce the difference in refractive index.

Conventionally, in the field of easy-adhesive films for optics, a technique for reducing rainbow unevenness by including specific fine particles in the easy-adhesion layer has been known (see, for example, Patent Document 1). However, although such a conventional technique is considered to have achieved a certain result in terms of adhesiveness and suppression of rainbow unevenness, there is a problem of easiness of scratching due to poor slidability, and in order to enhance slidability. However, when other particles are added to the composition, the transparency is lowered, and there is a problem that the slipperiness and the transparency and the low coherence for reducing the rainbow unevenness cannot be balanced.

JP, 2007-203712, A

With the development of mobile technology, the use of mobile devices such as mobile phones, car navigation systems and electronic books in the outdoor area is expanding. In addition, most of the above-mentioned portable devices are liquid crystal panel displays from the viewpoint of thinning. In such fields, for example, in a mobile phone equipped with a touch panel, as a hard coat film for protecting the surface of the display, interference fringes due to reflected light from both interfaces in contact with the coating surface or an icon sheet is used as a design on the back surface of the hard coat film. In the application to improve the property, the defect of visibility due to interference fringes is becoming more apparent.

However, when a large amount of a high-refractive-index additive is added in order to obtain high low coherence, the transparency is impaired, and the low coherence and the transparency may not be compatible with each other. Further, since it is also used for a high-definition display, even if a slipperiness was added to improve scratch resistance in order to suppress scratches, there were cases where transparency could not be maintained.

Furthermore, in order to improve productivity in recent years, strong friction is applied to the coating layer as the speed of post-processing such as lamination of hard coat layer and slit processing increases, and scratches on the coating layer have not been a problem until now. Thickness variation and quality variation are becoming issues. In particular, the resin used for increasing the refractive index has a relatively high hardness and is fragile, and thus the coating layer in which the interference unevenness is suppressed tends to have a larger scratch resistance.

Therefore, there is a strong demand for an optical adhesion polyester film which has the effect of suppressing interference unevenness, and further has transparency and high adhesion to a hard coat layer without causing scratches in the coating layer even at high speed processing.

The present invention has been made against the background of the problems of the related art. That is, the object of the present invention is to have an excellent balance of properties such as slipperiness and transparency, excellent handleability at the time of manufacturing and in a later step such as a polarizing plate manufacturing step of a liquid crystal display device, with less scratches, and rainbow unevenness. An object of the present invention is to provide an easily-adhesive polyester film which can be suitably used in optical applications, which is also excellent in low interference for suppression.

The present inventor has completed the present invention as a result of extensive studies to achieve such an object. That is, the present invention has the following configurations.
1. A polyester film having a coating layer on at least one surface, wherein the coating layer contains zirconia/titania mixed particles A, lubricant particles B, and a binder resin, and is based on the total mass of zirconia and titania in the zirconia/titania mixed particles A. An easily adhesive polyester film in which the content of zirconia is 55% by mass or more and 90% by mass or less , and the thickness of the coating layer is 0.001 μm or more and 2 μm or less.
2. The easily-adhesive polyester film according to the above 1, wherein the lubricant particles B have an average particle diameter of 200 nm or more.
3. The easily adhesive polyester film according to the above 1st or 2nd, wherein the zirconia/titania mixed particles A have an average particle diameter of 5 to 200 nm.
4. The easily adhesive polyester film according to any one of the above first to third, wherein the content of the lubricant particles B with respect to the solid content of the coating layer is 0.1 to 20% by mass.
5. The easily adhesive polyester film according to any one of the first to fourth aspects, wherein the content of the zirconia/titania mixed particles A with respect to the solid content of the coating layer is 2 to 50% by mass.
6. Selected from the group consisting of a hard coat layer, an antiglare layer, an antiglare antireflection layer, an antireflection layer and a low reflection layer on the coating layer of the easily adhesive polyester film according to any one of the first to fifth aspects. A laminated polyester film having one or more functional layers.

According to the present invention, low interference that can suppress rainbow unevenness can be secured, an excellent balance between transparency and slipperiness, less scratches, and handling at the time of manufacturing or a post-process such as a polarizing plate manufacturing process of a liquid crystal display device. It has become possible to provide an easily-adhesive polyester film that can be suitably used in optical applications having excellent properties.

(Polyester film)
The polyester film used as the substrate in the present invention is a film made of a polyester resin, and is preferably a polyester film containing at least one of polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate and polyethylene naphthalate as a constituent component. .. Further, it may be a film in which the third component monomer is a copolyester as described above. Among these polyester films, the polyethylene terephthalate film is most preferable from the viewpoint of balance between physical properties and cost.

Further, the polyester film may be a single layer or a multilayer. In addition, each of these layers may contain various additives in the polyester resin, if necessary, as long as the effects of the present invention are achieved. 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.

(Coating layer)
The easily adhesive polyester film of the present invention is one in which an easily adhesive coating layer is laminated on the above polyester base film. The coating layer contains zirconia/titania mixed particles A (hereinafter sometimes simply referred to as particles A), lubricant particles B (hereinafter sometimes simply referred to as particles B), and a binder resin.

Particle A is a zirconia/titania mixed particle. The mixed particles referred to in the present invention are a group of particles containing both zirconia and titania in an aggregated state in which zirconia and titania are individually dispersed in a single liquid and do not form a complex. Of course, in the coating layer, the liquid component is almost completely evaporated in the drying process and the curing process. By including such particles A in the coating layer, a good balance between slipperiness and transparency can be obtained, and high transparency and low interference can be secured. The liquid is preferably an aqueous liquid so that the coating layer can be easily formed by a so-called in-line coating method described later.

The particles A may contain other components other than zirconia/titania, may be inorganic particles or organic particles, and are not particularly limited, but include silica and dioxide. Examples of the inorganic particles are inert to metal oxides such as titanium, zirconium oxide, talc and kaolinite, and polyesters such as calcium carbonate, calcium phosphate and barium sulfate.

The ratio of the total mass of zirconia and titania to the mass of particles A that are mixed particles (not including the mass of liquid) is preferably 70 mass% or more, more preferably 80 mass% or more, and further preferably 90 mass. % Or more. Of course, it may be 100% by mass. It is preferable that the ratio of the total mass of zirconia and titania in the particles A is 70% by mass or more because the slipperiness and the transparency are balanced.

The ratio of the mass of zirconia to the total mass of zirconia and titania constituting the particles A that are mixed particles is preferably 10 mass% or more, more preferably 20 mass% or more, and further preferably 30 mass% or more. Is more preferable, 40% by mass or more is particularly preferable, 50% by mass or more is still more preferable, and 55% by mass or more is most preferable. When the ratio of the mass of zirconia to the total mass of zirconia and titania is 10% by mass or more, the surface roughness does not become too large, the slipperiness with the guide roll becomes appropriate, and scratches are less likely to occur. Therefore, haze does not increase and the transparency is excellent.

The ratio of the mass of zirconia to the total mass of zirconia and titania constituting the particles A is preferably 90 mass% or less, more preferably 85 mass% or less, further preferably 80 mass% or less, and particularly It is preferably 77% by mass or less. When the ratio of the mass of zirconia to the total mass of zirconia and titania is 90 mass% or less, the surface roughness does not become too small, the proper slipperiness is maintained, the handling property is good, and unrolling is performed. Sometimes it is not easily scratched, which is preferable.

The ratio of the mass of titania to the total mass of zirconia and titania constituting the particles A is preferably 10% by mass or more, more preferably 15% by mass or more, further preferably 20% by mass or more, particularly preferably 23% by mass. % Or more. When the ratio of the mass of titania to the total mass of zirconia and titania is 10% by mass or more, slipperiness is improved, handling is improved, and scratch resistance is favorable, which is preferable. However, increasing the ratio of the mass of titania to the total mass of zirconia and titania means that the ratio of the mass of zirconia decreases, so it is preferably 90% by mass or less, and more preferably 80% by mass. Or less, more preferably 70% by mass or less, particularly preferably 60% by mass or less, further preferably 50% by mass or less, and most preferably 45% by mass or less.

The average particle size of the particles A is preferably 5 nm or more, more preferably 10 nm or more, further preferably 15 nm or more, and particularly preferably 20 nm or more. It is preferable that the average particle diameter of the particles A is 5 nm or more because aggregation is less likely to occur.

The average particle size of the particles A is preferably 200 nm or less, more preferably 150 nm or less, further preferably 100 nm or less, and particularly preferably 60 nm or less. It is preferable that the average particle size of the particles A is 200 nm or less because transparency is good.

Particle B is (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. , Inorganic particles such as diatomaceous earth, calcium silicate, aluminum hydroxide, hydrohalloysite, magnesium carbonate, magnesium hydroxide, (2) acrylic or methacrylic, vinyl chloride, vinyl acetate, nylon, styrene/acrylic, Styrene/butadiene system, polystyrene/acrylic system, polystyrene/isoprene system, polystyrene/isoprene system, methylmethacrylate/butylmethacrylate system, melamine system, polycarbonate system, urea system, epoxy system, urethane system, phenol system, diallylphthalate system Examples thereof include organic particles such as polyester-based particles, and silica is particularly preferably used in order to impart appropriate lubricity to the coating layer.

The average particle size of the particles B is preferably 200 nm or more, more preferably 250 nm or more, further preferably 300 nm or more, and particularly preferably 350 nm or more. When the average particle diameter of the particles B is 200 nm or more, aggregation is less likely to occur, and slipperiness can be secured, which is preferable.

The average particle diameter of the particles B is preferably 2000 nm or less, more preferably 1500 nm or less , further preferably 1000 nm or less , and particularly preferably 700 nm or less . When the average particle diameter of the particles B is 2000 nm or less, transparency is maintained and the particles do not fall off, which is preferable.

The particles A and B may be surface-treated, and the surface treatment methods include physical surface treatment such as plasma discharge treatment and corona discharge treatment and chemical surface treatment using a coupling agent. Is preferably used. As the coupling agent, an organoalkoxy metal compound (eg, titanium coupling agent, silane coupling agent) is preferably used. When the particles B are silica, the silane coupling treatment is particularly effective. It may be used as a surface treatment agent for the particles B for preliminarily performing surface treatment before preparing the layer coating solution, or may be added to the layer as an additive when preparing the layer coating solution. Of course, it may be used for the particles A.

The binder resin that constitutes the coating layer is not particularly limited as long as it is a resin that provides easy adhesion, and specific examples of the polymer include polyester resin, acrylic resin, urethane resin, polyvinyl resin (polyvinyl alcohol, etc.), polyalkylene. Examples thereof include glycol, polyalkyleneimine, methylcellulose, hydroxycellulose, starches and the like. Among these, polyester resin, acrylic resin, and urethane resin are preferably used from the viewpoint of particle retention and adhesion. Further, in consideration of the compatibility with the polyester film, the polyester resin is most suitable. You may use these binder resins together.

The polyester resin may be contained in the coating layer in an amount of 100% by mass based on all solid components, but is preferably contained in an amount of 10% by mass or more and 90% by mass or less. It is more preferably 20% by mass or more and 80% by mass or less. When the content of the polyester resin is 90% by mass or less, the adhesion with the hard coat layer under high temperature and high humidity is maintained, which is preferable. On the contrary, when the content is 10% by mass or more, the presence of other urethane resin or the like maintains the adhesiveness to the polyester film under normal temperature, high temperature and high humidity, which is preferable.

In the present invention, the coating layer may contain a crosslinking agent in order to form a crosslinked structure in the coating layer. By including a cross-linking agent, it becomes possible to further improve the adhesiveness under high temperature and high humidity. Specific crosslinking agents include urea-based, epoxy-based, melamine-based, isocyanate-based, oxazoline-based, carbodiimide-based and the like. Among these, melamine-based, isocyanate-based, oxazoline-based, and carbodiimide-based cross-linking agents are preferable from the viewpoint of the stability of the coating liquid over time and the effect of improving adhesion under high temperature and high humidity treatment. Further, in order to accelerate the crosslinking reaction, a catalyst or the like can be appropriately used if necessary.

The content of the cross-linking agent in the coating layer is preferably 5% by mass or more and 50% by mass or less based on all solid components. More preferably, it is 10% by mass or more and 40% by mass or less. When the content is 10% by mass or more, the strength of the resin in the coating layer is maintained and the adhesion under high temperature and high humidity is good, and when the content is 40% by mass or less, the flexibility of the resin in the coating layer is maintained, Adhesion at room temperature, high temperature and high humidity is maintained, which is preferable.

The content of the particles A in the coating layer is preferably 2% by mass or more, more preferably 3% by mass or more, further preferably 4% by mass or more, and particularly preferably 5% by mass or more. When the content of the particles A in the coating layer is 2% by mass or more, the refractive index of the coating layer can be kept high, and low coherence can be effectively obtained, which is preferable.

The content of the particles A in the coating layer is preferably 50% by mass or less, more preferably 40% by mass or less, further preferably 30% by mass or less, and particularly preferably 20% by mass or less. When the content of the particles A in the coating layer is 50% by mass or less, the film forming property is maintained, which is preferable.

The content of particles B in the coating layer is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and further preferably 1% by mass or more. It is preferable that the content of the particles B in the coating layer is 0.1% by mass or more, since proper slipperiness is maintained.

The content of particles B in the coating layer is preferably 20% by mass or less, more preferably 15% by mass or less, and further preferably 10% by mass or less. When the content of the particles B in the coating layer is 20% by mass or less, the haze is kept low, which is preferable in terms of transparency.

The thickness of the coating layer is preferably 0.001 μm or more, more preferably 0.01 μm or more, still more preferably 0.02 μm or more, and particularly preferably 0.05 μm or more. When the thickness of the coating layer is 0.001 μm or more, good adhesion is obtained, which is preferable.

The thickness of the coating layer is preferably 2 μm or less, more preferably 1 μm or less, further preferably 0.8 μm or less, and particularly preferably 0.5 μm or less. When the film thickness of the coating layer is 2 μm or less, blocking is not likely to occur, which is preferable.

The coating layer may contain a surfactant for the purpose of improving the leveling property during coating and defoaming the coating liquid. The surfactant may be any of cationic, anionic and nonionic surfactants, but silicone, acetylene glycol or fluorine surfactants are preferred. These surfactants are preferably contained in the coating layer in a range that does not impair the effect of suppressing the iris color under fluorescent light and the adhesiveness.

In order to impart other functionality to the coating layer, various additives may be contained within a range that does not impair the effect of suppressing iris-like color under a fluorescent lamp and the adhesiveness. Examples of the additives include fluorescent dyes, fluorescent brighteners, plasticizers, ultraviolet absorbers, pigment dispersants, foam suppressors, defoamers, and preservatives.

As the coating method, a so-called in-line coating method in which the polyester base film is coated at the time of film formation, and a so-called off-line coating method in which the polyester base film is coated and then separately coated by a coater can be applied. The in-line coating method is efficient and more preferable.

As a coating method, any known method can be used as a method for applying the coating liquid to a polyethylene terephthalate (hereinafter abbreviated as PET) film. For example, reverse roll coating method, gravure coating method, kiss coating method, die coater method, roll brushing method, spray coating method, air knife coating method, wire bar coating method, pipe doctor method, impregnation coating method, curtain coating method, etc. To be These methods are applied individually or in combination.

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

The solid content concentration of the coating liquid depends on the type of binder resin and the type of solvent, but is preferably 2% by mass or more, and more preferably 4% by mass. The solid content concentration of the coating liquid is preferably 35% by mass or less, more preferably 15% by mass or less.

The drying temperature after coating also depends on the type of binder resin, the type of solvent, the presence/absence of a crosslinking agent, the solid content concentration, etc., but is preferably 80° C. or higher, and preferably 250° C. or lower.

The surface roughness (Ra) of the coating layer is related to the slipperiness and the like of the surface of the coating layer, and is preferably 0.01 nm or more, more preferably 0.1 nm or more, further preferably 0.2 nm or more. And particularly preferably 0.5 nm or more. On the other hand, the upper limit of the surface roughness (Ra) of the coating layer is preferably 200 nm or less, more preferably 100 nm or less, still more preferably 80 nm or less, and particularly preferably 50 nm or less.

(Production of easily adhesive polyester film for optics)
The easily adhesive polyester film for optics of the present invention can be manufactured according to a general method for manufacturing a polyester film. For example, a polyester resin is melted, and a non-oriented polyester extruded and molded into a sheet shape is stretched in the longitudinal direction by utilizing a speed difference of rolls at a temperature of a glass transition temperature or higher, and then stretched in a lateral direction by a tenter, A method of applying heat treatment may be mentioned.

The polyester film of the present invention may be a uniaxially stretched film or a biaxially stretched film, but when the biaxially stretched film is used as a protective film for the liquid crystal panel front surface, it is observed from directly above the film surface. Even though no iridescent color spots are seen, it should be noted that iridescent color spots may be observed when observed from an oblique direction.

This phenomenon is because the biaxially stretched film is composed of a refractive index ellipsoid having different refractive indices in the running direction, the width direction and the thickness direction, and the retardation becomes zero depending on the light transmission direction inside the film (refractive index ellipse). This is because there is a direction in which the body looks like a perfect circle. Therefore, when the liquid crystal display screen is observed from a specific diagonal direction, a point where the retardation becomes zero may occur, and rainbow-shaped color spots are concentrically formed around the point. If the angle from just above the film surface (in the normal direction) to the position where the iridescent color spot is visible is θ, this angle θ increases as the birefringence in the film surface increases, and the iridescent color The spots are hard to see. Since the angle θ tends to be small in the biaxially stretched film, the uniaxially stretched film is preferable because the rainbow-shaped color spots are less visible.

However, a perfect uniaxial (uniaxially symmetric) film is not preferable because the mechanical strength in the direction perpendicular to the orientation direction is significantly reduced. INDUSTRIAL APPLICABILITY The present invention has biaxiality (biaxial symmetry) in a range in which substantially no rainbow-like color spots are generated, or in a range where a viewing angle range required for a liquid crystal display screen is not generated. Preferably.

(Laminated polyester film)
The laminated polyester film mainly used in the optical application of the present invention is a hard coat layer made of an electron beam or ultraviolet curable acrylic resin or a siloxane thermosetting resin on the coating layer of the easily adhesive polyester film of the present invention. And the like are provided.

It is also a preferable mode to provide a functional layer on the coating layer of the easily adhesive polyester film of the present invention. The functional layer, for the purpose of preventing glare, glare control, rainbow unevenness control, scratch control, and the like, in addition to the hard coat layer described above, an antiglare layer, an antiglare antireflection layer, an antireflection layer, a low reflection layer and A layer having functionality such as an antistatic layer. As the functional layer, various types known in the art can be used, and the type thereof is not particularly limited. Hereinafter, each functional layer will be described.

For example, for forming the hard coat layer, a known hard coat layer can be used, and is not particularly limited, but drying, heat, a chemical reaction, or electron beam, radiation, polymerization by irradiation with ultraviolet rays, Resin compounds that react and/or react can be used. Examples of such curable resins include melamine-based, acrylic-based, silicone-based, and polyvinyl alcohol-based curable resins, but photocurable acrylic-based curable resins from the viewpoint of obtaining high surface hardness or optical design. Resins are preferred. As such an acrylic curable resin, a polyfunctional (meth)acrylate monomer or an acrylate oligomer can be used, and examples of the acrylate oligomer include polyester acrylate, epoxy acrylate, urethane acrylate, and polyacrylate. Examples thereof include ether acrylate type, polybutadiene acrylate type, and silicone acrylate type. A coating composition for forming the optical functional layer can be obtained by mixing a reaction diluent, a photopolymerization initiator, a sensitizer and the like with these acrylic curable resins.

The hard coat layer may have an antiglare function (antiglare function) that scatters external light. The antiglare function (antiglare function) can be obtained by forming irregularities on the surface of the hard coat layer. At this time, the haze of the film is ideally preferably 0 to 50%, more preferably 0 to 40%, and particularly preferably 0 to 30%. Of course, 0% is ideal, and may be 0.2% or more, or 0.5% or more.

Therefore, the application of the film of the present invention is mainly applied to optical films in general, and is applicable to optical elements such as prism lens sheet, AR (anti-reflection) film, hard coat film, diffusion plate, shatterproof film, LCD, flat TV and CRT. It can be suitably used for a base film of a member, a near-infrared absorption filter that is a member for a front plate for a plasma display, a transparent conductive film for a touch panel, electroluminescence, and the like.

More specifically, the acrylic resin that is cured by electron beams or ultraviolet rays for forming the hard coat layer is one having an acrylate-based functional group, and for example, a polyester resin, a polyether resin, or an acrylic resin having a relatively low molecular weight. , Epoxy resin, urethane resin, alkyd resin, spiro acetal resin, polybutadiene resin, polythiol polyene resin, oligomer or prepolymer such as (meth)acrylate of polyfunctional compound such as polyhydric alcohol and ethyl (meth) as a reactive diluent Monofunctional and polyfunctional monomers such as acrylate, ethylhexyl (meth)acrylate, styrene, methylstyrene and N-vinylpyrrolidone, for example, trimethylolpropane tri(meth)acrylate, hexanediol(meth)acrylate, tripropylene glycol di( (Meth)acrylate, diethylene glycol di(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, etc. What is contained can be used.

However, in the case of electron beam or ultraviolet ray curable resin, as a photopolymerization initiator in the above-mentioned resin, acetophenones, benzophenones, Michler benzoyl benzoate, α-amyloxime ester, tetramethylthylium monosulfide, thioxanthone And n-butylamine, triethylamine, tri-n-butylphosphine, etc. can be mixed and used as a photosensitizer.

The silicone-based (siloxane-based) thermosetting resin can be produced by subjecting an organosilane compound to a single or a mixture of two or more in the presence of an acid or base catalyst, followed by a hydrolysis and condensation reaction. In particular, in the case of low reflection, it is more preferable to mix one or more fluorosilane compounds for hydrolysis and condensation reaction in order to improve low refractive index property and stain resistance.

(Production of laminated polyester film)
The method for producing the laminated polyester film in the present invention will be described by taking the easily adhesive polyester film as an example, but the present invention is not limited to this.

The electron beam or ultraviolet ray curable acrylic resin or siloxane thermosetting resin is coated on the coating layer surface of the easily adhesive polyester film. When the coating layer is provided on both sides, the coating is applied to at least one coating layer surface. It is not necessary to dilute the coating solution, but there is no particular problem if it is diluted with an organic solvent according to the viscosity, wettability, coating film thickness, etc. of the coating solution. The coating layer is obtained by applying the coating solution to the above-mentioned film, drying it if necessary, and then curing the coating layer by electron beam or ultraviolet irradiation and heating according to the curing conditions of the coating solution. Forming a hard coat layer.

In the present invention, the hard coat layer preferably has a thickness of 1 to 15 μm. When the thickness of the hard coat layer is 1 μm or more, the effects on the chemical resistance, scratch resistance, antifouling property, etc. of the hard coat layer are efficiently exhibited, which is preferable. On the other hand, when the thickness is 15 μm or less, the flexibility of the hard coat layer is maintained and cracks and the like are not likely to occur, which is preferable.

As for the scratch resistance, it is preferable that the scratches are not visually noticeable when the coated surface is abraded with a black mount. If the scratches are not noticeable in the above evaluation, scratches are less likely to occur when passing through the guide rolls, which is preferable from the viewpoint of handleability and the like.

The lower limit of the static friction coefficient (μs) is preferably 0.3, and if it is 0.3 or more, there is no problem of excessive slippage, so winding up with a hard chrome plated roll or the like becomes easy in the manufacturing process. It is preferable because handling property and blocking resistance are maintained. The upper limit of the coefficient of static friction (μs) is preferably 0.5, and when it is 0.5 or less, there is no fear of scratching the film which is the contacting surface during winding, which is preferable.

The lower limit of the dynamic friction coefficient (μd) is preferably 0.4, and when it is 0.4 or more, there is no problem of excessive slippage, so winding up with a hard chrome plated roll or the like becomes easy in the manufacturing process. It is preferable because handling property and blocking resistance are maintained. The upper limit of the coefficient of kinetic friction (μd) is preferably 0.6, and it is preferably 0.6 or less because there is no risk of scratching the film to be the contacting surface during winding.

Since the polyester film of the present invention is mainly used as an easily adhesive film for optics, it preferably has high transparency. The lower limit of haze is ideally 0%, and the closer to 0%, the more preferable. The upper limit of haze is preferably 2%, and is preferably 2% or less because the light transmittance is good and a clear image can be obtained in a liquid crystal display device. The haze of the polyester film can be measured, for example, according to the method described below.

Regarding the adhesion between the coating layer having an easily adhesive layer property and the hard coat layer, the lower limit is preferably 80%, and the upper limit is preferably 100%, as evaluated by the measurement method described below. When it is 80% or more, it can be said that the adhesiveness between the coating layer and the hard coat layer is sufficiently maintained.

Regarding the adhesion between the easy-adhesion layer and the hard coat layer evaluated according to the method described below under high temperature and high humidity conditions, the lower limit is preferably 10%, and the upper limit of the high temperature and high humidity adhesion is preferably 100%. is there. When it is 10% or more, the adhesion between the easy-adhesion layer and the hard coat layer is satisfied once under the high temperature and high humidity condition, and the passage property in the post-processing step is satisfied generally. More preferably, it is 50% or more.

The polyester film for protecting a polarizer formed with a hard coat is preferably incapable of confirming interference spots by the evaluation method described below, and if the interference spots cannot be confirmed by the evaluation method, the visibility of the liquid crystal image device becomes good. preferable.

The easily adhesive polyester film of the present invention can be used in various applications, but is preferably used in a manufacturing process of a polarizing plate used in a liquid crystal display device, and particularly preferably used as a protective film of a polarizer constituting the polarizing plate. It is what is done. Usually, many polarizers are made of polyvinyl alcohol, and the easily-adhesive polyester film of the present invention is adhered to the polarizer using an adhesive made of polyvinyl alcohol or a cross-linking agent or the like as necessary. In that case, it is more preferable that the coating layer of the easily adhesive polyester film of the present invention is used not on the surface on the side to be bonded to the polarizer but on the opposite surface. The surface of the easily-adhesive polyester film of the present invention, which is adhered to the polarizer, includes, for example, an easily-adhesive film containing a polyester-based resin, a polyvinyl alcohol-based resin, and a crosslinking agent as described in WO 2012/105607. The layers are preferably laminated.

Next, the present invention will be described in detail with reference to Examples, Comparative Examples, and Reference Examples, but the present invention is not limited to the following Examples. The evaluation method used in the present invention is as follows.

(1) Average particle size [measurement method by scanning electron microscope]
The average particle size of the above particles can be measured by the following method. The particles are photographed with a scanning electron microscope (SEM), and the maximum diameter of 300 to 500 particles (between the two most distant points) is magnified at a magnification such that the size of one of the smallest particles is 2 to 5 mm. The distance) is measured, and the average value is taken as the average particle size. The average particle size of the particles present in the coating layer in the present invention can be measured by the measuring method.

[Dynamic light scattering method]
The average particle size of the particles can also be determined by the dynamic scattering method at the time of producing the particles or the film. The sol was diluted with a dispersion medium, measured with a submicron particle analyzer N4 PLUS (manufactured by Beckman Coulter, Inc.) using the parameters of the dispersion medium, and the average particle diameter was obtained by calculating with the cumulant method. In the dynamic light scattering method, the average particle size of particles in the sol is observed, and when particles are aggregated, the average particle size of the aggregated particles is observed.

(2) Refractive index of particles
The refractive index of particles can be measured by the following method. After drying the inorganic particles at 150°C, crushing the powder crushed in a mortar and immersing it in Solvent 1 (having a lower refractive index than the particles), Solvent 2 (having a higher refractive index than the particles) is almost transparent. Was added until. The refractive index of this liquid was measured using an Abbe refractometer (Abbe refractometer manufactured by Atago Co., Ltd.). The measurement was performed at 23° C. and D line (wavelength 589 nm). As the solvent 1 and the solvent 2, those which can be mixed with each other are selected, and depending on the refractive index, for example, 1,1,1,3,3,3-hexafluoro-2-propanol, 2-propanol, chloroform, tetrachloride. Solvents such as carbon, toluene, glycerin and the like can be mentioned.

(3) Haze of Easy-Adhesive Polyester Film The haze of the easily-adhesive polyester film was measured using a turbidimeter (NDH2000, manufactured by Nippon Denshoku Co., Ltd.) according to JIS K 7136:2000.

(4) Adhesion The hard coat layer described in the item of forming the hard coat layer was formed on the easy-adhesion layer of the polyester film obtained in the example. The polyester film for easy adhesion having a hard coat is adhered between the hard coat layer and the base film in accordance with the description in JIS-K5400-1990 8.5.1.

Specifically, using a cutter guide having a gap of 2 mm, 100 square cuts penetrating the hard coat layer and reaching the base film are made on the hard coat layer surface. Then, a cellophane adhesive tape (Nichiban, No. 405; width of 24 mm) is attached to the cut surface of the grid and rubbed with an eraser to completely adhere it. After that, the cellophane adhesive tape was vertically peeled off from the hard coat layer surface of the hard coat laminated polarizer protective film, and the number of squares peeled off from the hard coat layer surface of the hard coat laminated polarizer protective film was visually counted. Then, the adhesion between the hard coat layer and the base film is obtained. It should be noted that those that are partially peeled in the squares are counted as peeled squares.

Adhesion (%)={1-(number of peeled squares/100)}×100

(5) Moisture and heat resistance The above-mentioned laminated film for protecting a polarizer on which a hard coat is formed is left to stand in an environment of 85° C. and 85 RH% for 500 hours in a high temperature and high humidity tank, and then the hard coat laminated polarizer protective film is taken out. It was left at room temperature for 12 hours. After that, the adhesion between the hard coat layer and the substrate film was obtained by the same method as described above, and the wet heat resistance was obtained.

(6) Static friction coefficient, dynamic friction coefficient (μs, μd)
The coefficient of friction of the polyester films obtained in the examples was measured using Tensilon (Toyo Baldwin, RTM-100) in accordance with JIS K7125-1999 Plastic-Film and sheet friction coefficient test method.

(7) Improvement of interference fringes (iris-like color)
A hard coat layer was formed on the easy adhesion layer of the easy adhesion optical polyester film obtained in each example. The optical adhesion polyester film having a hard coat formed thereon 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 (Nitto Denko KK, vinyl tape No21; black) was attached to the surface of the obtained sample film opposite to the hard coat layer surface. With the hard coat surface of this sample film as the upper surface, a three-wavelength daylight white (National Palook, FL 15EX-N 15W) is used as the light source, and the position where the strongest reflection can be seen visually from diagonally above (the distance from the light source is 40 ~ It was observed at 60 cm and an angle of 15 to 45°.

The results of visual observation are ranked according to the following criteria. In addition, the observation is performed by 5 persons who are familiar with the evaluation, and the highest rank is set as the evaluation rank. If two ranks have the same number, the center of three ranks is adopted. For example, if ◎ and ○ are each 2 people and △ is 1 person, ○, if ◎ is 1 person and ○ and △ are 2 people respectively, ○, ◎ and △ are 2 people each and ○ is 1 In the case of first name, ○ is adopted.
⊚: No iris-like color is observed even when observed from any angle ○: Slight iris-like color is seen at a certain angle Δ: Slight iris-like color is observed ×: Clear iris-like color is observed Be done

(8) Scratch resistance of coating layer A 3 cm (film width direction) x 20 cm (film longitudinal direction) of an optical adhesion polyester film was attached to a friction fastness tester (manufactured by Daiei Kagaku Seiki Seisakusho, RT-200). , A black mount (thickness 80 μm, arithmetic average surface roughness 0.03 μm) was used for the contact portion between the load head portion (2 cm×2 cm, 200 g) with a weight (300 g) and the sample film, and 10 c
It was reciprocated 3 times at a speed of 20 seconds per reciprocation. The obtained sample film was placed on a black mount and visually checked for scratches.
○: No scratches can be confirmed on the black mount, or slight scratches can be confirmed depending on the place △: Slight scratches can be confirmed on the black mount overall ×: Scratches are clearly confirmed on the black mount it can

(9) Glass transition temperature
According to JIS K7121-1987, using a differential scanning calorimeter (manufactured by Seiko Instruments, DSC6200), 10 mg of a resin sample was heated at 20° C./min over a temperature range of 25 to 300° C., and obtained from a DSC curve. The extrapolated glass transition onset temperature was defined as the glass transition temperature.

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

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

(12) Surface roughness (Ra)
Ra was measured by Surfcom (registered trademark) 304B (manufactured by Tokyo Seimitsu Co., Ltd.) based on JIS-B0601-2001. The measurement conditions were a cutoff of 0.08 μm, a probe radius of 2 μm, a measurement length of 0.8 mm, and a measurement speed of 0.03 mm/sec.

(Polymerization of polyester resin)
In a stainless steel autoclave equipped with a stirrer, a thermometer, and a partial reflux condenser, 194.2 parts by mass of dimethyl terephthalate, 184.5 parts by mass of dimethyl isophthalate, 14.8 parts by mass 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 the transesterification reaction was carried out at a temperature of 160° C. to 220° C. for 4 hours. Next, the temperature was raised to 255° C., the pressure of the reaction system was gradually reduced, and the reaction was performed under reduced pressure of 30 Pa for 1 hour and 30 minutes to obtain a copolyester resin (I). The obtained copolyester resin (I) was light yellow and transparent. When the reduced viscosity of the copolyester resin (I) was measured, it was 0.70 dl/g. The glass transition temperature by DSC was 40° C., and the number average molecular weight was 20,000.
The composition of the copolyester resin (I) is as follows.
Dicarboxylic acid formation: 49% by mole of terephthalic acid, 48% by mole of isophthalic acid, 3% by mole of 5-sodium isophthalic acid
Diol component: 40 mol% ethylene glycol, 60 mol% diethylene glycol

(Production of polyester aqueous dispersion)
30 parts by mass of the copolymerized polyester resin (I) and 15 parts by mass of ethylene glycol-n-butyl ether were placed in a reactor equipped with a stirrer, a thermometer and a reflux device, and heated at 110° C. and stirred to dissolve the resin. After the resin was completely dissolved, 55 parts by mass of water was gradually added to the polyester solution with stirring. After the addition, the liquid was cooled to room temperature with stirring to prepare a milky white polyester water dispersion (Iα) having a solid content of 28.2% by mass.

(Production of polyurethane water dispersion)
In a four-necked flask equipped with a stirrer, a Dimroth condenser, a nitrogen introduction tube, a silica gel drying tube, and a thermometer, 43.75 parts by mass of 4,4-dicyclohexylmethane diisocyanate, 12.85 parts by mass of dimethylolbutanoic acid, 153.41 parts by mass of polyhexamethylene carbonate diol having a number average molecular weight of 2000, 0.03 parts by mass of dibutyltin dilaurate, and 84.00 parts by mass of acetone as a solvent were added, and the mixture was stirred at 75° C. for 3 hours in a nitrogen atmosphere to react. It was confirmed that the liquid reached a predetermined amine equivalent. Next, this reaction liquid was cooled to 40° C., and then 8.77 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, the temperature was adjusted to 25° C., and the polyurethane prepolymer solution was added and dispersed in water while stirring and mixing at 2000 min ⁻¹ . .. Then, acetone and part of water were removed under reduced pressure to prepare a water-soluble polyurethane resin solution (II) having a solid content of 37% by mass. The glass transition temperature of the obtained polyurethane resin (II) was -30°C.

(Polymerization of block polyisocyanate cross-linking agent)
Stirrer, thermometer, polyisocyanate compound having an isocyanurate structure using hexamethylene diisocyanate as a raw material in a flask equipped with a reflux condenser 100 parts by mass (Duranate TPA manufactured by Asahi Kasei Chemicals) 100 parts by mass, propylene glycol monomethyl ether acetate 55 parts by mass, 30 parts by mass of polyethylene glycol monomethyl ether (average molecular weight 750) was charged and kept at 70° C. for 4 hours under a nitrogen atmosphere. Then, the reaction liquid temperature was lowered to 50° C., and 47 parts by mass of methyl ethyl ketoxime was added dropwise. The infrared spectrum of the reaction solution was measured, and it was confirmed that the absorption of the isocyanate group had disappeared to obtain a blocked polyisocyanate aqueous dispersion (III) having a solid content of 75% by mass.

(Polymerization of oxazoline crosslinking agent)
A flask equipped with a thermometer, a nitrogen gas introduction tube, a reflux condenser, a dropping funnel, and a stirrer was mixed with 58 parts by mass of ion-exchanged water as an aqueous medium and 58 parts by mass of isopropanol, and a polymerization initiator (2,2). 4 parts by mass of'-azobis(2-amidinopropane) dihydrochloride) was added. On the other hand, in the dropping funnel, 16 parts by mass of 2-isopropenyl-2-oxazoline as a polymerizable unsaturated monomer having an oxazoline group, methoxy polyethylene glycol acrylate (average number of moles of ethylene glycol added: 9 moles, Shin Nakamura Chemical Co., Ltd. 32 parts by mass and 32 parts by mass of methyl methacrylate were added, and the mixture was added dropwise at 70° C. for 1 hour under a nitrogen atmosphere. After completion of the dropping, the reaction solution was stirred for 9 hours and cooled to obtain a water-soluble resin (IV) having an oxazoline group having a solid content concentration of 40% by mass.

(Polymerization of carbodiimide type crosslinking agent)
A flask equipped with a stirrer, a thermometer, and a reflux condenser was charged with 168 parts by mass of hexamethylene diisocyanate and 220 parts by mass of polyethylene glycol monomethyl ether (M400, average molecular weight 400), and the mixture was stirred at 120° C. for 1 hour. 26 parts by weight of 4'-dicyclohexylmethane diisocyanate and 3.8 parts by weight of 3-methyl-1-phenyl-2-phosphoren-1-oxide (2% by weight based on total isocyanate) as a carbodiimidization catalyst were added, and the mixture was flown under a nitrogen stream of 185. Stirred for an additional 5 hours at °C. The infrared spectrum of the reaction solution was measured, and it was confirmed that the absorption at the wavelength of 2200 to 2300 cm ^-1 had disappeared. The mixture was allowed to cool to 60° C., and 567 parts by mass of ion-exchanged water was added to obtain a carbodiimide water-soluble resin (V) having a solid content of 40% by mass.

(Epoxy cross-linking agent)
As an epoxy-based cross-linking agent, Denacol EX-521 (solid content concentration 100%) manufactured by Nagase Chemtex Co., Ltd. was used (epoxy-based cross-linking agent (VI)).

(Melamine crosslinking agent)
Beckamine M-3 (solid content concentration 60%) manufactured by DIC was used as the melamine-based crosslinking agent (melamine-based crosslinking agent (VII)).

(Zirconia particles)
In a 3 liter glass container, 2283.6 g of pure water and 403.4 g of oxalic acid dihydrate were charged and heated to 40° C. to prepare a 10.72 mass% oxalic acid aqueous solution. After stirring this aqueous solution, 495.8 g of zirconium oxycarbonate powder (ZrOCO ₃ , manufactured by AMR International Corp., containing 39.76% by mass in terms of ZrO ₂ ) was gradually added and mixed for 30 minutes. Then, heating was performed at 90° C. for 30 minutes. Next, 1747.2 g of a 25.0 mass% tetramethylammonium hydroxide aqueous solution (manufactured by Tama Chemical Industry Co., Ltd.) was gradually added over 1 hour. At this point, the mixed liquid was in the form of a slurry and contained 4.0 mass% in terms of ZrO ₂ . This slurry was transferred to a stainless steel autoclave container and subjected to hydrothermal treatment at 145° C. for 5 hours. The product after the hydrothermal treatment was completely sol-free with no deflocculated substances. The obtained sol contained 4.0% by mass as ZrO ₂ , pH 6.8, and the average particle size by dynamic light scattering method was 19 nm. The transmittance of the sol measured by adjusting the ZrO ₂ concentration to 2.0% by mass with pure water was 88%. When the particles were observed with a transmission electron microscope, most of the aggregated particles of ZrO ₂ primary particles having a size of about 7 nm were found. 4000 g of zirconia sol having a ZrO ₂ concentration of 4.0 mass% obtained by performing the above hydrothermal treatment was washed and concentrated while gradually adding pure water using an ultrafiltration device to obtain a ZrO ₂ concentration of 953 g of zirconia sol having a transmittance of 76% when 13.1% by mass, pH 4.9, and ZrO ₂ concentration of 13.1% by mass was obtained.

After adding 3.93 g of a 20 mass% citric acid aqueous solution and 11.0 g of a 25 mass% tetramethylammonium hydroxide aqueous solution to 300 g of zirconia sol having a ZrO ₂ concentration of 13.1 mass% obtained by performing the above washing and concentration. When further concentrated by an ultrafiltration device, 129 g of high-concentration zirconia sol having a ZrO ₂ concentration of 30.5% by mass was obtained. The obtained high-concentration zirconia sol had a pH of 9.3 and an average particle diameter of 19 nm measured by a dynamic light scattering method. Further, this zirconia sol had no sediment and was stable for 1 month or longer under the condition of 50°C.

(Titania particles)
12.09 kg of titanium tetrachloride aqueous solution containing titanium tetrachloride (manufactured by Osaka Titanium Technologies Co., Ltd.) at 7.75 mass% based on TiO ₂ and ammonia water containing 15 mass% of ammonia (manufactured by Ube Industries, Ltd.) ) 4.69 kg was mixed to prepare a white slurry liquid having a pH of 9.5. Next, this slurry was filtered and then washed with pure water to obtain 9.87 kg of a hydrous titanic acid cake having a solid content of 10% by mass. Next, 11.28 kg of hydrogen peroxide solution (manufactured by Mitsubishi Gas Chemical Co., Inc.) containing 35% by mass of hydrogen peroxide and 20.00 kg of pure water were added to this cake, and then at a temperature of 80° C. for 1 hour. Then, the mixture was heated with stirring, and 57.52 kg of pure water was further added to obtain 98.67 kg of an aqueous titanic acid peroxide solution containing 1% by mass of titanic acid peroxide on the basis of TiO ₂ . This aqueous solution of peroxytitanic acid had a transparent yellowish brown color and had a pH of 8.5.

Next, 4.70 kg of a cation exchange resin (manufactured by Mitsubishi Chemical Co., Ltd.) was mixed with 98.67 kg of the aqueous solution of titanic acid peroxide, and potassium stannate (manufactured by Showa Kako Co., Ltd.) was converted into SnO ₂ in this mixture. 12.33 kg of a potassium stannate aqueous solution containing 1% by mass based on the standard was gradually added with stirring. Next, after separating the cation exchange resin incorporating potassium ions and the like, the cation exchange resin was placed in an autoclave (manufactured by Pressure Resistant Glass Industry Co., Ltd., 120 L) and heated at a temperature of 165° C. for 18 hours.

Next, the obtained mixed aqueous solution was cooled to room temperature and then concentrated with an ultrafiltration membrane device (ACV-3010 manufactured by Asahi Kasei Co., Ltd.) to obtain titanium-based fine particles having a solid content of 10% by mass ( Hereinafter, 9.90 kg of a water-dispersed sol containing (P-1) was obtained. When the solid matter contained in the sol thus obtained was measured by the above method, it was found to be titanium-based fine particles (primary particles) having a rutile-type crystal structure and composed of a composite oxide containing titanium and tin. It was Furthermore, when the content of the metal component contained in the titanium-based fine particles was measured, based on the oxide conversion standard of each metal component, TiO _{2 was} 87.2 mass %, SnO _{2 was} 11.0 mass %, and K ₂ O. It was 1.8% by mass. The pH of the mixed aqueous solution was 10.0. Further, the aqueous dispersion sol containing the titanium-based fine particles is transparent and milky white, the average particle diameter of the titanium-based fine particles contained in the water-dispersed sol is 35 nm, and further, of coarse particles having a particle diameter of 100 nm or more. The distribution frequency was 0%. Furthermore, the refractive index of the obtained titanium-based fine particles could be considered to be 2.42.

(Zirconia/titania mixed particles)
The zirconia particles and the titania particles obtained above were mixed in respective ratios to prepare zirconia/titania mixed particles having a solid content concentration of 13% by mass.

(Formation of hard coat layer)
A coating liquid for forming a hard coat layer having the following composition was coated on a surface of the polyester film manufactured in each of the examples described later on the side opposite to the surface to be bonded to the polarizer using a #10 wire bar, and the coating liquid was applied at 70° C. for 1 minute. It was dried and the solvent was removed. Then, the film coated with the hard coat layer was irradiated with ultraviolet rays of 300 mJ/cm ² using a high pressure mercury lamp to obtain a polarizer protective film having a hard coat layer with a thickness of 5 μm.
・Coating liquid for forming hard coat layer
Methyl ethyl ketone 65.00 mass%
Dipentaerythritol hexaacrylate 27.20% by mass
(Shin-Nakamura Chemical A-DPH)
Polyethylene diacrylate 6.80 mass%
(Shin-Nakamura Chemical A-400)
Photopolymerization initiator 1.00% by mass
(Irgacure 184 manufactured by Ciba Specialty Chemicals)

(Example 1)
(Adjustment of coating liquid)
A coating solution having the following composition was prepared.
Water 34.94 parts by mass Isopropyl alcohol 30.00 parts by mass Particles A-1 7.24 parts by mass (zirconia/titania mixed particles having an average particle size of 23 nm,
75% by mass of zirconia based on the total mass of zirconia/titania,
Solid content concentration 13% by mass)
Particle B-1 0.90 parts by mass (silica sol having an average particle size of 450 nm, solid content concentration 40% by mass)
Polyester aqueous dispersion (Iα) 17.92 parts by mass (solid content concentration 28.2% by mass)
2.90 parts by mass of blocked isocyanate cross-linking agent (III) (concentration of solid content: 75% by mass)
Surfactant 0.30 parts by mass (fluorine-based, solid content concentration 10% by mass)
High boiling solvent 3.00 parts by mass Dispersion aid 0.26 parts by mass

(Production of easily adhesive polyester film)
As the film raw material polymer, PET resin pellets having an intrinsic viscosity (solvent: phenol/tetrachloroethane=60/40) of 0.62 dl/g and containing substantially no particles were used under a reduced pressure of 133 Pa at 135° C. Dried for hours. Then, it supplied to an extruder, melted and extruded into a sheet at about 280° C., and rapidly cooled and adhered to solidify on a rotating cooling metal roll kept 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 roll groups having different peripheral speeds to obtain a uniaxially stretched PET film.

Next, the coating liquid was applied onto one side of the PET film by a roll coating method, and then dried at 80° C. for 15 seconds. The coating amount after drying after the final stretching was adjusted to 0.12 g/m ² . Subsequently, with a tenter, the film was stretched 4.0 times in the width direction at 150° C., and while the length in the width direction of the film was fixed, it was heated at 230° C. for 0.5 seconds, and further at 230° C. for 10 seconds 3 % Relaxation treatment was performed in the width direction to obtain an easy-adhesion polyester film having a thickness of 38 μm.

(Reference example 2)
Instead of the particles A-1 of the coating liquid, an easily adhesive polyester film was prepared in the same manner as in Example 1 except that the ratio of the mass of zirconia to the total mass of zirconia and titania was changed to particles A-2. Got

(Reference example 3)
Instead of the particles A-1 of the coating liquid, an easily adhesive polyester film was prepared in the same manner as in Example 1 except that the ratio of the mass of zirconia to the total mass of zirconia and titania was changed to particles A-3. Got

(Example 4)
An easily adhesive polyester film was obtained in the same manner as in Example 1 except that the coating liquid having the following composition was prepared and used instead of the coating liquid prepared and used in Example 1.
Water 37.23 parts by mass Isopropyl alcohol 30.00 parts by mass Particles A-1 3.79 parts by mass (zirconia/titania mixed particles having an average particle size of 23 nm,
75% by mass of zirconia based on the total mass of zirconia/titania,
Solid content concentration 13% by mass)
Particle B-1 0.95 parts by mass (silica sol having an average particle size of 450 nm, solid content concentration 40% by mass)
18.77 parts by mass of polyester aqueous dispersion (Iα) (solid content concentration 28.2% by mass)
Block isocyanate isocyanate cross-linking agent (III) 3.03 parts by mass (solid content concentration 75% by mass)
Surfactant 0.30 parts by mass (fluorine-based, solid content concentration 10% by mass)
High boiling solvent 3.00 parts by mass Dispersion aid 0.27 parts by mass

(Example 5)
An easily adhesive polyester film was obtained in the same manner as in Example 1 except that the coating liquid having the following composition was prepared and used instead of the coating liquid prepared and used in Example 1.
Water 32.85 parts by mass Isopropyl alcohol 30.00 parts by mass Particles A-1 10.39 parts by mass (zirconia/titania mixed particles having an average particle size of 23 nm,
75% by mass of zirconia based on the total mass of zirconia/titania,
Solid content concentration 13% by mass)
Particle B-1 0.87 parts by mass (silica sol having an average particle size of 450 nm, solid content concentration 40% by mass)
17.15 parts by mass of polyester aqueous dispersion (Iα) (solid content concentration 28.2% by mass)
2.80 parts by mass of blocked isocyanate cross-linking agent (III) (concentration of solid content: 75% by mass)
Surfactant 0.30 parts by mass (fluorine-based, solid content concentration 10% by mass)
High boiling point solvent 3.00 parts by mass Dispersion aid 0.25 parts by mass

(Example 6)
An easily adhesive polyester film was obtained in the same manner as in Example 1 except that the coating liquid having the following composition was prepared and used instead of the coating liquid prepared and used in Example 1.
Water 39.17 parts by mass Isopropyl alcohol 30.00 parts by mass Particle A-1 7.24 parts by mass (zirconia/titania mixed particles having an average particle size of 23 nm,
75% by mass of zirconia based on the total mass of zirconia/titania,
Solid content concentration 13% by mass)
Particle B-1 0.90 parts by mass (silica sol having an average particle size of 450 nm, solid content concentration 40% by mass)
Polyurethane water dispersion (II) 13.70 parts by mass (solid content concentration 37% by mass)
2.90 parts by mass of blocked isocyanate cross-linking agent (III) (concentration of solid content: 75% by mass)
Surfactant 0.30 parts by mass (fluorine-based, solid content concentration 10% by mass)
High boiling solvent 3.00 parts by mass Dispersion aid 0.26 parts by mass

(Example 7)
An easily adhesive polyester film was obtained in the same manner as in Example 1 except that the coating liquid having the following composition was prepared and used instead of the coating liquid prepared and used in Example 1.
Water 34.94 parts by mass Isopropyl alcohol 30.00 parts by mass Particles A-1 7.24 parts by mass (zirconia/titania mixed particles having an average particle size of 23 nm,
75% by mass of zirconia based on the total mass of zirconia/titania,
Solid content concentration 13% by mass)
Particle B-1 0.90 parts by mass (silica sol having an average particle size of 450 nm, solid content concentration 40% by mass)
Polyester water dispersion (Iα) 13.27 parts by mass (solid content concentration 28.2% by mass)
Polyurethane aqueous dispersion (II) 4.98 parts by mass (solid content concentration 37% by mass)
2.90 parts by mass of blocked isocyanate cross-linking agent (III) (concentration of solid content: 75% by mass)
Surfactant 0.30 parts by mass (fluorine-based, solid content concentration 10% by mass)
High boiling solvent 3.00 parts by mass Dispersion aid 0.26 parts by mass

(Example 8)
An easily adhesive polyester film was obtained in the same manner as in Example 1 except that the blocked isocyanate crosslinking agent (III) in the coating liquid was changed to the water-soluble resin (IV) having an oxazoline group and the content thereof was adjusted. It was

(Example 9)
The blocked isocyanate-based cross-linking agent (III) of the coating liquid is used as a carbodiimide water-soluble resin (V).
Except that the content was adjusted, and an easily adhesive polyester film was obtained in the same manner as in Example 1.

(Example 10)
An easily adhering polyester film was obtained in the same manner as in Example 1 except that the blocked isocyanate crosslinking agent (III) in the coating liquid was changed to the melamine crosslinking agent (VII) and the content was adjusted.

(Example 11)
An easily adhering polyester film was obtained in the same manner as in Example 1 except that the blocked isocyanate crosslinking agent (III) in the coating liquid was changed to the epoxy crosslinking agent (VI) and the content was adjusted.

(Example 12)
An easily-adhesive polyester film was obtained in the same manner as in Example 1 except that the particles A-4 having an average particle diameter of 40 nm were changed in place of the particles A-1 of the coating liquid.

(Example 13)
An easily-adhesive polyester film was obtained in the same manner as in Example 1, except that the particle A-1 of the coating liquid was changed to the particle A-5 having an average particle diameter of 30 nm.

(Example 14)
An easily-adhesive polyester film was obtained in the same manner as in Example 1 except that the thickness of the coating layer was changed to 0.05 μm.

(Example 15)
An easily adhesive polyester film was obtained in the same manner as in Example 1 except that the thickness of the coating layer was changed to 0.075 μm.

(Example 16)
An easily-adhesive polyester film was obtained in the same manner as in Example 1 except that the thickness of the coating layer was changed to 0.125 μm.

(Example 17)
An easily adhesive polyester film was obtained in the same manner as in Example 1 except that the coating liquid having the following composition was prepared and used instead of the coating liquid prepared and used in Example 1.
Water 35.40 parts by mass Isopropyl alcohol 30.00 parts by mass Particles A-1 7.26 parts by mass (zirconia/titania mixed particles having an average particle size of 23 nm,
75% by mass of zirconia based on the total mass of zirconia/titania,
Solid content concentration 13% by mass)
Particle B-1 0.36 parts by mass (silica sol having an average particle size of 450 nm, solid content concentration 40% by mass)
Polyester water dispersion (Iα) 17.98 parts by mass (solid content concentration 28.2% by mass)
2.90 parts by mass of blocked isocyanate cross-linking agent (III) (concentration of solid content: 75% by mass)
Surfactant 0.30 parts by mass (fluorine-based, solid content concentration 10% by mass)
High boiling solvent 3.00 parts by mass Dispersion aid 0.26 parts by mass

(Example 18)
An easily adhesive polyester film was obtained in the same manner as in Example 1 except that the coating liquid having the following composition was prepared and used instead of the coating liquid prepared and used in Example 1.
Water 34.48 parts by weight Isopropyl alcohol 30.00 parts by weight Particles A-1 7.22 parts by weight (zirconia/titania mixed particles having an average particle size of 23 nm,
75% by mass of zirconia based on the total mass of zirconia/titania,
Solid content concentration 13% by mass)
Particle B-1 1.44 parts by mass (silica sol having an average particle size of 450 nm, solid content concentration 40% by mass)
Polyester water dispersion (Iα) 17.88 parts by mass (solid content concentration 28.2% by mass)
2.90 parts by mass of blocked isocyanate cross-linking agent (III) (concentration of solid content: 75% by mass)
Surfactant 0.30 parts by mass (fluorine-based, solid content concentration 10% by mass)
High boiling solvent 3.00 parts by mass Dispersion aid 0.26 parts by mass

(Comparative Example 1)
An easily adhering polyester film was obtained in the same manner as in Example 1 except that the non-mixed zirconia single particles A-6 containing no titania were used instead of the particles A-1 of the coating liquid.

(Comparative example 2)
Instead of the particles A-1 of the coating liquid, the same procedure as in Example 1 was carried out except that the non-mixed titania-based single particles A-7 containing no zirconia were changed to adjust the mass% in consideration of the solid content concentration. An easily adhesive polyester film was obtained.

(Comparative example 3)
An easily adhesive polyester film was obtained in the same manner as in Example 1 except that the coating liquid having the following composition was prepared and used instead of the coating liquid prepared and used in Example 1.
Water 35.71 parts by mass Isopropyl alcohol 30.00 parts by mass Particles A-1 7.27 parts by mass (zirconia/titania mixed particles having an average particle size of 23 nm,
75% by mass of zirconia based on the total mass of zirconia/titania,
Solid content concentration 13% by mass)
Polyester water dispersion (Iα) 28.58 parts by mass (solid content concentration 28.2% by mass)
Block isocyanate type cross-linking agent (III) 1.38 parts by mass (solid content concentration 75% by mass)
Surfactant 0.30 parts by mass (fluorine-based, solid content concentration 10% by mass)
High boiling solvent 3.00 parts by mass Dispersion aid 0.26 parts by mass

The easily-adhesive polyester film obtained in each example has good scratch resistance, a static friction coefficient and a dynamic friction coefficient are appropriate, and transparency, adhesion, moist-heat resistance, and low interference are also satisfied. The result was good. On the other hand, the easily adhesive polyester film obtained in Comparative Example 1 was not satisfactory in wet heat resistance because the particles A in the coating layer did not contain zirconia. Further, the easily adhesive polyester film obtained in Comparative Example 2 was not satisfactory in scratch resistance because the particles A in the coating layer did not contain titania. The easily adhesive polyester film obtained in Comparative Example 3 had a large friction coefficient because the lubricant particles B in the coating layer were not included.

(Example 19)
On the coating layer of the easily adhesive polyester film obtained in Example 1, a coating solution for forming an antiglare layer having the following composition was coated using a #5 wire bar and dried at 70° C. for 1 minute to remove the solvent. did. Then, the film coated with the antiglare layer was irradiated with ultraviolet rays of 300 mJ/cm ² using a high pressure mercury lamp to obtain a laminated polyester film having an antiglare layer having a thickness of 5 μm. A preferred laminated polyester film having antiglare properties was obtained.
・Coating liquid for forming antiglare layer
34 parts by mass of toluene
Pentaerythritol triacrylate 50 parts by mass
12 parts by mass of silica (average particle size 1 μm)
Silicone (leveling agent) 1 part by weight
Photopolymerization initiator 1 part by mass
(Irgacure 184 manufactured by Ciba Specialty Chemicals)

(Example 20)
On the coating layer of the easily adhesive polyester film obtained in Example 1, a coating liquid for forming a medium refractive index layer having the following composition was applied using a bar coater, dried at 70° C. for 1 minute, and then using a high pressure mercury lamp. Ultraviolet rays of 400 mJ/cm ² were irradiated to obtain a medium refractive index layer having a dry film thickness of 5 μm. Next, on the formed medium-refractive index layer, using a bar coater, a coating liquid for forming a high-refractive-index layer having the following composition is formed in the same manner as for the medium-refractive index layer, and further having the following composition The coating liquid for forming the low refractive index layer was formed in the same manner as for the medium refractive index layer to obtain a laminated polyester film having an antireflection layer laminated thereon. A preferred laminated polyester film having antireflection properties was obtained.

・Coating liquid for forming medium refractive index layer (refractive index 1.52)
Dipentaerythritol hexaacrylate 70 parts by mass
1,6-bis(3-acryloyloxy-2-hydroxypropyloxy)hexane
30 parts by mass
Photopolymerization initiator 4 parts by mass
(Irgacure 184 manufactured by Ciba Specialty Chemicals Co., Ltd.)
100 parts by mass of isopropanol
・Coating liquid for forming high refractive index layer (refractive index 1.64)
ITO fine particles (average particle size 0.07 μm) 85 parts by mass
Tetramethylol methanetriacrylate 15 parts by mass
Photopolymerization initiator (KAYACURE BMS, manufactured by Nippon Kayaku) 5 parts by mass
Butyl alcohol 900 parts by mass
・Coating liquid for forming low refractive index layer (refractive index 1.42)
1,10-Diacryloyloxy-2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9-hexadecafluorodecane 70 parts by mass
Dipentaerythritol hexaacrylate 10 parts by mass
60 parts by mass of silica gel particles (XBA-ST, manufactured by Nissan Kagaku)
Photopolymerization initiator (KAYACURE BMS, manufactured by Nippon Kayaku) 5 parts by mass

Claims (6)

A polyester film having a coating layer on at least one surface, wherein the coating layer contains zirconia/titania mixed particles A, lubricant particles B, and a binder resin, and is based on the total mass of zirconia and titania in the zirconia/titania mixed particles A. An easily adhesive polyester film in which the content of zirconia is 55% by mass or more and 90% by mass or less , and the thickness of the coating layer is 0.001 μm or more and 2 μm or less. The easily adhesive polyester film according to claim 1, wherein the lubricant particles B have an average particle diameter of 200 nm or more. The easily adhesive polyester film according to claim 1 or 2, wherein the zirconia/titania mixed particles A have an average particle diameter of 5 to 200 nm. The easily adhesive polyester film according to any one of claims 1 to 3, wherein the content of the lubricant particles B with respect to the solid content of the coating layer is 0.1 to 20% by mass. The easily adhesive polyester film according to any one of claims 1 to 4, wherein the content of the zirconia/titania mixed particles A with respect to the solid content of the coating layer is 2 to 50% by mass. It is selected from the group consisting of a hard coat layer, an antiglare layer, an antiglare antireflection layer, an antireflection layer and a low reflection layer on the coating layer of the easily adhesive polyester film according to any one of claims 1 to 5. A laminated polyester film having one or more functional layers.