WO2012144425A1 - Laminated polyester film - Google Patents

Abstract

Provided is a laminated polyester film for use in decorative laminates or decorative sheets. This laminated polyester film does not cause environmental problems in incineration, and can yield a decorative laminate or sheet which is not influenced by the color tone of a substrate and does not suffer from conspicuous interference unevenness as observed from the surface side of a clear hardcoat and which thus has highly designed or excellently patterned surface appearance. The laminated polyester film is a polyester film that is for use in decorative laminates or sheets produced by disposing at least a film layer and a hardcoat layer successively on the surface of a substrate and can serve as the film layer and that exhibits a transmission density of 0.1 to 5.0 and has a primer layer on at least one surface on which the hardcoat layer is to be disposed, said primer layer being a layer formed from a coating fluid (A) that contains a metal oxide, an oxazoline compound and an epoxy compound (or a coating fluid (B) that contains a metal oxide, a polyester resin containing a naphthalene skeleton, and an isocyanate compound).

Description

Laminated polyester film

The present invention relates to a polyester film for a decorative board or a decorative sheet. The decorative board as used herein means that at least a film layer and a hard coat layer are sequentially arranged on the surface of the base material, and if necessary, a pattern printing layer is arranged between the film layer and the hard coat layer. It is a building material (surface material) that is usually handled as a single product, and a decorative sheet is bonded to the surface of the base material of various products such as various furniture, building materials, and housing equipment, and a hard coat layer is formed on the surface. Or the decorative material (surface material) used by arrange | positioning a pattern printing layer and a hard-coat layer one by one. Therefore, the film layer, the pattern printing layer, and the hard coat layer arranged on the substrate surface of the decorative board are elements constituting the decorative board or the decorative sheet.

As a sheet used between the base material of the decorative board and the pattern printed layer and a sheet (film) used for the decorative sheet, a vinyl chloride resin sheet is most common. However, when a vinyl chloride resin sheet is used, the plasticizer blended in the sheet moves to the adhesive layer on the bonding surface and causes poor adhesion, and the thermal dimensional stability of the vinyl chloride resin sheet is poor. Therefore, there is a problem that expansion and contraction due to heat occurs and causes wrinkles. Furthermore, in recent years, demand for decorative sheets and decorative sheets that do not use a vinyl chloride resin sheet has increased due to environmental problems during incineration.

By the way, as described above, since the decorative board and the decorative sheet are used as surface materials, a high-design pattern is usually applied to the surface. For this reason, color tone management is extremely important in order to produce a subtle contrast between a pattern and a shadow. That is, a wide variety of materials such as plywood (particle board) and steel plate are used for the base material of the decorative board and the base material on which the decorative sheet is bonded. The color tone of these base materials is, for example, the same material. Even so, it is customary that they are different.

Therefore, when the concealment degree of the sheet constituting the decorative sheet is poor, the color tone of the base material affects the color tone of the surface of the decorative plate or the decorative sheet, and the design is impaired. Therefore, a sheet (film) having a concealing property is desired as a decorative sheet so that it can be widely applied to substrates having various color tones.

On the other hand, biaxially oriented polyester films represented by polyethylene terephthalate are used in many fields because of their excellent properties. For example, it has been proposed to use a polyester film as a surface member of a decorative board (Patent Document 1). It has also been proposed to use a polyester film between the substrate and the pattern printing layer (Patent Document 2).

By the way, the polyester film is generally inferior in adhesiveness with various materials when compared with the vinyl chloride resin film or sheet. Therefore, when a polyester film is used in place of the vinyl chloride resin film or sheet, for example, the adhesiveness with the hard coat layer and the picture print layer is lowered. A decorative board is used for surface decorations, such as various furniture and a door. Therefore, when peeling between the film and the substrate occurs, the appearance is remarkably impaired, and such peeling must be avoided.

In order to improve the adhesion between the polyester film and the hard coat layer, an easily adhesive primer layer is generally provided as an intermediate layer. For this reason, interference unevenness occurs unless the refractive index of the three layers of the polyester film, the easy-adhesion primer layer, and the hard coat layer is taken into consideration.

Also, when viewed from the surface of the clear hard coat layer, there is a problem that interference unevenness is particularly noticeable in a portion having no pattern and the appearance is impaired. Therefore, there is a strong demand for a film having an excellent appearance without causing such interference unevenness when viewed from a clear hard coat surface.

If a film with uneven interference is used for a decorative board or a decorative sheet, the appearance impression is poor, and the appearance of a high-design surface or a pattern is inferior. Therefore, it is required to take measures against interference unevenness. In general, the refractive index of the primer layer for reducing interference unevenness is considered to be around the geometric mean of the refractive index of the polyester film of the substrate and the refractive index of the hard coat layer, and is adjusted to the refractive index around this. Ideally. Since the biaxially stretched polyester film has a high refractive index, it is generally necessary to design the primer layer to have a high refractive index.

An example of improving interference unevenness by increasing the refractive index of the primer layer is, for example, a method of increasing the refractive index in the primer layer by combining a metal oxide having a high refractive index and a polymer binder in the primer layer. (Patent Document 3). As another example, there is a method of combining a metal chelate compound and a resin (Patent Document 4). In this case, the stability of the coating solution may not be sufficient depending on the combination due to the instability of the metal chelate in the aqueous solution, which may lead to an increase in the liquid exchange work when producing for a long time. . Moreover, in order to improve the interference unevenness by these methods, the hard coat layer formed on the primer layer in order to suppress the occurrence of interference unevenness due to the primer layer being dissolved in the solvent and changing the thickness of the primer layer. It may be necessary to select a solvent to be used for forming the surface functional layer. Therefore, for example, a quick-drying solvent used for improving productivity, a leveling agent used for improving the surface condition, various solvents for improving the solubility of the resin used for the surface functional layer, etc. There is a need for a primer layer that can be used without problems.

JP-A-7-17005 JP-A-10-128934 JP 2004-54161 A JP 2005-97571 A

The present invention has been made in view of the above circumstances, and the solution is not to cause environmental problems at the time of incineration, and is not affected by the color tone of the base material, when viewed from a clear hard coat surface. Another object of the present invention is to provide a laminated polyester film for a decorative board or a decorative sheet that is excellent in the appearance of a high-design surface or a picture pattern without causing interference unevenness.

As a result of intensive studies in view of the above problems, the present inventors have found that the above problems can be easily solved by a polyester film having a specific configuration, and have completed the present invention. The present invention comprises two related inventions, and the gist of each invention is as follows.

The gist of the first invention is a polyester film used for the film layer of a decorative board or a decorative sheet in which at least a film layer and a hard coat layer are sequentially arranged on the surface of a substrate, and the transmission of the polyester film It has a concentration of 0.1 to 5.0, and has a primer layer formed from a coating solution containing a metal oxide, an oxazoline compound, and an epoxy compound on at least one surface on which the hard coat layer is disposed. It exists in a laminated polyester film.

The gist of the second invention is a polyester film used for the film layer of a decorative board or decorative sheet in which at least a film layer and a hard coat layer are sequentially arranged on the surface of a substrate, and the transmission of the polyester film It has a primer layer formed from a coating solution containing a metal oxide, a polyester resin containing a naphthalene skeleton, and an isocyanate compound on at least one surface where the concentration is 0.1 to 5.0 and the hard coat layer is disposed. It exists in the laminated polyester film characterized by this.

According to the present invention, there is no environmental problem at the time of incineration, it is not affected by the color tone of the base material, it is possible to display a high-design pattern, and the adhesion to the base material and the printed layer The decorative plate or the polyester film for a decorative sheet can be provided which has excellent printability and adhesiveness, and is excellent in appearance by suppressing interference unevenness in actual use, and the industrial value of the present invention is very large.

(Polyester film)
The polyester referred to in the present invention refers to a polymer containing an ester group obtained by polycondensation from a dicarboxylic acid and a diol or hydroxycarboxylic acid. Examples of the dicarboxylic acid include terephthalic acid, isophthalic acid, adipic acid, azelaic acid, sebacic acid, 2,6-naphthalenedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, and the diol includes ethylene glycol, 1,4 -Butanediol, diethylene glycol, triethylene glycol, neopentyl glycol, 1,4-cyclohexanedimethanol, polyethylene glycol and the like. Examples of hydroxycarboxylic acids include p-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid. Is mentioned. Typical polyesters include polyethylene terephthalate, polyethylene-2, 6 naphthalate and the like. The polyester used in the present invention may be a homopolymer or a copolymer obtained by copolymerizing the third component.

In the polyester layer of the film of the present invention, particles may be blended mainly for the purpose of imparting slipperiness and preventing the occurrence of scratches in each step. The kind of the particle to be blended is not particularly limited as long as it is a particle capable of imparting slipperiness. Specific examples thereof include silica, calcium carbonate, magnesium carbonate, barium carbonate, calcium sulfate, calcium phosphate, and phosphoric acid. Examples of the particles include magnesium, kaolin, aluminum oxide, and titanium oxide. Further, the heat-resistant organic particles described in JP-B-59-5216, JP-A-59-217755 and the like may be used. Examples of other heat-resistant organic particles include thermosetting urea resins, thermosetting phenol resins, thermosetting epoxy resins, benzoguanamine resins, and the like. Furthermore, precipitated particles obtained by precipitating and finely dispersing a part of a metal compound such as a catalyst during the polyester production process can also be used.

The shape of the particles to be used is not particularly limited, and any of a spherical shape, a block shape, a rod shape, a flat shape, and the like may be used. Moreover, there is no restriction | limiting in particular also about the hardness, specific gravity, a color, etc. These series of particles may be used in combination of two or more as required.

The average particle size of the particles is usually 0.01 to 3 μm, preferably 0.01 to 2 μm. If the average particle size is less than 0.01 μm, the slipperiness may not be sufficiently imparted, or the particles may be aggregated to make the dispersibility insufficient, thereby reducing the transparency of the film. On the other hand, when the thickness exceeds 3 μm, the surface roughness of the film becomes too rough, and a problem may occur when various surface functional layers are applied in a subsequent process.

Further, the particle content in the polyester layer is usually 0.0001 to 5% by weight, preferably 0.0003 to 3% by weight. When the particle content is less than 0.0001% by weight, the slipperiness of the film may be insufficient. On the other hand, when the content exceeds 5% by weight, the transparency of the film is insufficient. There is.

The method for adding particles to the polyester layer is not particularly limited, and a conventionally known method can be adopted. For example, it can be added at any stage for producing the polyester constituting each layer, but it is preferably added after completion of esterification or transesterification.

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 blending of dried particles and a polyester raw material using a kneading extruder. It is done by methods.

In addition to the above-mentioned particles, conventionally known antioxidants, antistatic agents, thermal stabilizers, lubricants, dyes, pigments, and the like can be added to the polyester film in the present invention as necessary.

The thickness of the polyester film in the present invention is not particularly limited as long as it can be formed as a film, but is usually 10 to 300 μm, preferably 25 to 250 μm.

Next, a production example of the polyester film in the present invention will be specifically described, but is not limited to the following production examples. That is, a method of using the polyester raw material described above and cooling and solidifying a molten sheet extruded from a die with a cooling roll to obtain an unstretched sheet is preferable. In this case, in order to improve the flatness of the sheet, it is preferable to improve the adhesion between the sheet and the rotary cooling drum, and an electrostatic application adhesion method and / or a liquid application adhesion method is preferably employed. Next, the obtained unstretched sheet is stretched in the biaxial direction. In that case, first, the unstretched sheet is stretched in one direction by a roll or a tenter type stretching machine. The stretching temperature is usually 70 to 120 ° C., preferably 80 to 110 ° C., and the stretching ratio is usually 2.5 to 7 times, preferably 3.0 to 6 times. Next, the film is stretched in the direction perpendicular to the first stretching direction. In this case, the stretching temperature is usually 70 to 170 ° C., and the stretching ratio is usually 3.0 to 7 times, preferably 3.5 to 6 times. is there. Subsequently, heat treatment is performed at a temperature of 180 to 270 ° C. under tension or relaxation within 30% to obtain a biaxially oriented film. In the above-described stretching, a method in which stretching in one direction is performed in two or more stages can be employed. In that case, it is preferable to carry out so that the draw ratios in the two directions finally fall within the above ranges.

In the present invention, the simultaneous biaxial stretching method can be adopted for the production of the polyester film constituting the laminated polyester film. The simultaneous biaxial stretching method is a method in which the unstretched sheet is stretched and oriented simultaneously in the machine direction and the width direction in a state of temperature control usually at 70 to 120 ° C., preferably 80 to 110 ° C. Is usually 4 to 50 times, preferably 7 to 35 times, and more preferably 10 to 25 times in terms of area magnification. Subsequently, heat treatment is performed at a temperature of 170 to 250 ° C. under tension or under relaxation within 30% to obtain a stretched oriented film. With respect to the simultaneous biaxial stretching apparatus that employs the above-described stretching method, a conventionally known stretching method such as a screw method, a pantograph method, or a linear driving method can be employed.

The decorative sheet in the present invention is widely applied to base materials having various color tones as described above. Therefore, it is important that the polyester film of the present invention has a concealing property so that the color tone of the decorative sheet does not change depending on the color tone of the base material and the high-level design property is not impaired. Therefore, in the present invention, the transmission density of the polyester film needs to be 0.1 to 5.0. The transmission density is preferably 0.2 to 4.0, more preferably 0.5 to 3.0, and particularly preferably 1.0 to 3.0.

The hiding property indicated by the above transmission density is generally obtained by incorporating inorganic or organic particles in the film. Examples of the particles include titanium dioxide, calcium carbonate, barium sulfate, aluminum oxide, silicon dioxide, carbon black, iron oxide, chromium oxide, etc., but they are used as long as the permeation concentration specified in the present invention can be satisfied. The kind of particle | grains is not limited to said example.

Further, as a method for imparting concealing property, a method in which closed small bubbles are contained in the polyester film can be preferably employed. Specific examples include a method in which a small amount of polyolefin that is incompatible with polyester is added to the polyester for stretching and heat setting, a method in which an inert gas is contained in the polyester film, and the like.

When the transmission density of the polyester film is less than 0.1, the color tone of the substrate to which the polyester film is attached affects the color tone of the pattern on the decorative sheet surface, and the object of the present invention cannot be achieved. In order to make the transmission density of the polyester film greater than 5.0, it is usually necessary to increase the amount of additives to the film. This often causes film breakage during film production and decreases the mechanical strength of the polyester film. There is a problem that.

The polyester film of the present invention can provide a decorative board or a decorative sheet excellent in design without causing interference unevenness from the surface of the clear hard coat layer formed on the surface thereof.

The polyester film of the present invention allows a highly designed surface pattern to appear on a decorative sheet without being affected by the color tone of the substrate. Therefore, it is possible to achieve a so-called single-layer surface printing by sticking a decorative sheet having a pattern printed on the polyester film of the present invention to the surface of the substrate. The decorative sheet is suitable for building materials, furniture, housing equipment, automobile interiors, and the like. Furthermore, in single-layer surface printing, after concealing printing is performed on a polyester film, pattern printing may be performed on the polyester film, or embossing may be performed on a design-required portion after pattern printing. A coat may be applied.

Since the polyester film of the present invention is excellent in concealability, it is possible to form a single-layer surface printing with a polyester film consisting of only one layer, but a polyester film having two or more layers may be used. For example, by sequentially laminating a transparent layer and a layer imparting concealability on the surface polyester layer on the side where the hard coat layer is arranged, a high film between the clear surfaces can be obtained, or a substrate such as plywood The surface embossing can be facilitated by forming a multilayer structure in which a plurality of the polyester films of the present invention are attached.

On the other hand, if the dimensional stability of the decorative sheet is poor, problems such as wrinkles may occur in the printing process, or the design accuracy of the pattern may be impaired due to a decrease in alignment accuracy during printing. is there. In the present invention, the heat shrinkage ratio of the polyester film after heat treatment at 180 ° C. for 5 minutes is usually −5.0% to + 7.0%, preferably −3.0% to + 5.0% in both length and width. In particular, it is preferable that the heat shrinkage in the vertical direction is −2.0% to + 4.0% and the heat shrinkage in the horizontal direction is −1.0% to + 1.0%. When the thermal shrinkage rate is greater than −5.0%, the surface of the decorative sheet may swell and the appearance may be greatly impaired. When the heat shrinkage rate exceeds + 7%, problems such as peeling of the decorative sheet from building materials and furniture, and distortion of the design pattern may occur. In addition, that a shrinkage rate is a negative value represents that a film expand | extends after heat processing.

The color tone of the film of the present invention can be selected according to the color to be printed. For example, when used as a wood-based material, the color tone of the polyester film itself is adjusted to match the color tone of the bark, as a white film when used as a white material, and as a black film when used as a black material. preferable.

The film of the present invention prevents the occurrence of repelling and unevenness in the printing process due to electrification, prevents the risk of ignition due to the occurrence of sparks, and improves the handleability and stain prevention when used as a decorative sheet and decorative plate. In order to obtain the above effect, an antistatic agent may be included in the film layer or the primer layer on the surface of the film layer, and the surface specific resistance may be 1 × 10 ⁷ Ω to 1 × 10 ¹² Ω. If the surface resistivity is less than 1 × 10 ⁷ Ω, the effect is no longer saturated and no further improvement can be seen. In addition, a large amount of antistatic agent is required and the durability of the primer layer is increased. Insufficient durability when used as a decorative sheet or board, use of a special antistatic agent adversely affects the color of the printed layer, and the color tone of the film itself may not be as desired. Problems can occur.

Next, the formation of the primer layer constituting the laminated polyester film in the present invention will be described. Regarding the primer layer, it may be provided by in-line coating, which treats the film surface during the stretching process of the polyester film, or may be applied off-system on a once produced film, and may be adopted off-line coating. You may use together. Since it can be applied simultaneously with film formation, in-line coating is preferably used in that it can be manufactured at low cost and the thickness of the primer layer can be changed by the draw ratio.

In-line coating is a method of applying within the process of producing a polyester film. Specifically, it is a method of applying at any stage from melt-extrusion of polyester to biaxial stretching, heat setting and winding. is there. Usually applied to either a substantially amorphous unstretched sheet obtained by melting and quenching, a uniaxially stretched film stretched in the longitudinal direction (longitudinal direction), or a biaxially stretched film before heat setting. To do. In these, the method of extending | stretching to a horizontal direction after apply | coating to a uniaxially stretched film is excellent. According to such a method, since film formation and coating / drying can be performed simultaneously, there is a merit in manufacturing cost, thin film coating is easy to perform stretching after coating, and heat treatment performed after coating is not limited. Since the high temperature is not achieved by this method, the coating film and the polyester film are firmly adhered.

(Primer layer in the first invention)
In the first invention, it is an essential requirement to have a primer layer formed from a coating liquid containing a metal oxide, an oxazoline compound, and an epoxy compound on at least one surface of the polyester film.

More preferably, the primer layer has a primer layer in which the absolute reflectance has one minimum value in the wavelength range of 400 to 800 nm, and the absolute reflectance at the minimum value is 4.0% or more.

Metal oxide is mainly used for adjusting the refractive index of the primer layer. In particular, since the refractive index of the resin used in the primer layer is low, it is preferable to use a metal oxide having a high refractive index, and it is preferable to use a refractive index of 1.7 or more. Specific examples of the metal oxide include, for example, zirconium oxide, titanium oxide, tin oxide, yttrium oxide, antimony oxide, indium oxide, zinc oxide, antimontin oxide, indium tin oxide, and the like. You may use 2 or more types. Among these, zirconium oxide and titanium oxide are more preferably used. In particular, zirconium oxide is more preferably used from the viewpoint of weather resistance.

The metal oxide is preferably used in the form of particles because there is a concern that the adhesion may be lowered depending on the use form, and the average particle diameter is usually from the viewpoint of transparency and stability of the coating liquid. Among them, those having a small particle diameter are preferable because the refractive index of the primer layer can be easily adjusted while maintaining transparency. However, as described later, when used for the purpose of imparting easy handling properties such as slipperiness, a small amount of particles having an average particle size of 0.1 to 1.0 μm should be used within the range that does not impair transparency. Is also possible.

The oxazoline compound and the epoxy compound can improve the adhesion with a surface functional layer such as a hard coat layer provided on the primer layer. By using these two types of compounds in combination, the adhesion can be further improved, and in particular, the adhesion after the wet heat test can be improved.

As the oxazoline compound, a polymer containing an oxazoline group is particularly preferable, and such a polymer can be obtained by polymerization of an addition polymerizable oxazoline group-containing monomer alone or with another monomer. Addition polymerizable oxazoline group-containing monomers include 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, 2-vinyl-5-methyl-2-oxazoline, 2-isopropenyl-2-oxazoline 2-isopropenyl-4-methyl-2-oxazoline, 2-isopropenyl-5-ethyl-2-oxazoline, and the like, and one or a mixture of two or more thereof can be used. Of these, 2-isopropenyl-2-oxazoline is preferred because it is easily available industrially. The other monomer is not particularly limited as long as it is a monomer copolymerizable with an addition polymerizable oxazoline group-containing monomer. For example, alkyl (meth) acrylate (alkyl groups include methyl, ethyl, n-propyl, isopropyl, (Meth) acrylic acid esters such as n-butyl group, isobutyl group, t-butyl group, 2-ethylhexyl group, cyclohexyl group); acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, styrene Unsaturated carboxylic acids such as sulfonic acid and its salts (sodium salt, potassium salt, ammonium salt, tertiary amine salt, etc.); Unsaturated nitriles such as acrylonitrile, methacrylonitrile; (meth) acrylamide, N-alkyl ( (Meth) acrylamide, N, N-dialkyl (meth) acrylamide, Examples of the alkyl group include unsaturated amides such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl, 2-ethylhexyl, cyclohexyl, etc .; vinyl acetate Vinyl esters such as vinyl propionate; vinyl ethers such as methyl vinyl ether and ethyl vinyl ether; α-olefins such as ethylene and propylene; halogen-containing α, β-unsaturated monomers such as vinyl chloride, vinylidene chloride and vinyl fluoride And α, β-unsaturated aromatic monomers such as styrene and α-methylstyrene, and the like, and one or more of these monomers can be used.

Examples of the epoxy compound include condensates of epichlorohydrin and ethylene glycol, polyethylene glycol, glycerin, polyglycerin, bisphenol A and other hydroxyl groups and amino groups, such as polyepoxy compounds, diepoxy compounds, monoepoxy compounds, Examples include glycidylamine compounds. Examples of the polyepoxy compound include sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, diglycerol polyglycidyl ether, triglycidyl tris (2-hydroxyethyl) isocyanate, glycerol polyglycidyl ether, trimethylolpropane. Examples of the polyglycidyl ether and diepoxy compound include neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, resorcin diglycidyl ether, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, and propylene glycol diglycidyl ether. , Polypropylene glycol diglycidyl ether, poly Examples of tetramethylene glycol diglycidyl ether and monoepoxy compounds include allyl glycidyl ether, 2-ethylhexyl glycidyl ether, phenyl glycidyl ether, and glycidyl amine compounds such as N, N, N ′, N ′,-tetraglycidyl-m-. Examples include xylylenediamine and 1,3-bis (N, N-diglycidylamino) cyclohexane.

In the laminated polyester film of the present invention, for improving the coated surface, reducing interference unevenness when various surface functional layers such as a hard coat layer are laminated on the coated surface, improving transparency and adhesion, etc. It is preferable to use various polymers.

Specific examples of the polymer include polyester resin, acrylic resin, urethane resin, polyvinyl (polyvinyl alcohol, polyvinyl chloride, vinyl chloride vinyl acetate copolymer, etc.), polyalkylene glycol, polyalkyleneimine, methylcellulose, hydroxycellulose, starches. Etc. Among these, it is preferable to use a polyester resin, an acrylic resin, or a urethane resin from the viewpoint of improving adhesion with a surface functional layer such as a hard coat layer.

In order to make it easier to adjust the refractive index of the primer layer, it is preferable to use a compound having a condensed polycyclic aromatic structure as exemplified by the following formula.

In consideration of applicability on a polyester film, the compound having a condensed polycyclic aromatic is preferably a polymer compound such as a polyester resin, an acrylic resin, or a urethane resin. In particular, polyester resins are more preferable because more condensed polycyclic aromatics can be introduced.

As a method of incorporating the condensed polycyclic aromatic into the polyester resin, for example, two or more hydroxyl groups are introduced into the condensed polycyclic aromatic as a substituent to form a diol component or a polyvalent hydroxyl component, or There is a method in which two or more acid groups are introduced to prepare a dicarboxylic acid component or a polyvalent carboxylic acid component.

In the laminated polyester film production process, the condensed polycyclic aromatic is preferably a compound having a naphthalene skeleton in that it is difficult to be colored. In addition, a resin in which a naphthalene skeleton is incorporated as a polyester component is suitably used in terms of good adhesion to various surface functional layers formed on the primer layer and good transparency. Representative examples of the naphthalene skeleton include 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, and 2,7-naphthalenedicarboxylic acid.

In addition to the hydroxyl group and the carboxylic acid group, the condensed polycyclic aromatic has a refractive index of a refractive index by introducing a substituent containing a sulfur element, an aromatic substituent such as a phenyl group, a halogen element group, and the like. Improvement can be expected. Moreover, you may introduce | transduce substituents, such as an alkyl group, ester group, and an amide group, from an applicability | paintability or adhesive viewpoint.

Furthermore, the coating solution for forming the primer layer may contain a crosslinking agent other than the oxazoline compound and the epoxy compound within the range not impairing the gist of the present invention. Various known resins can be used as the crosslinking agent, and examples thereof include melamine compounds, isocyanate compounds, carbodiimide compounds, and the like.

The melamine compound is a compound having a melamine skeleton in the compound. For example, an alkylolated melamine derivative, a compound partially or completely etherified by reacting an alcohol with an alkylolated melamine derivative, and a mixture thereof can be used. As alcohol used for etherification, methyl alcohol, ethyl alcohol, isopropyl alcohol, n-butanol, isobutanol and the like are preferably used. Moreover, as a melamine compound, either a monomer or a multimer more than a dimer may be sufficient, or a mixture thereof may be used. Further, a product obtained by co-condensing urea or the like with a part of melamine can be used, and a catalyst can be used to increase the reactivity of the melamine compound.

The isocyanate compound is a compound derived from an isocyanate derivative typified by isocyanate or blocked isocyanate. Examples of isocyanates include aromatic isocyanates such as tolylene diisocyanate, xylylene diisocyanate, methylene diphenyl diisocyanate, phenylene diisocyanate, and naphthalene diisocyanate, and aromatic rings such as α, α, α ′, α′-tetramethylxylylene diisocyanate. Aliphatic isocyanates such as aliphatic isocyanate, methylene diisocyanate, propylene diisocyanate, lysine diisocyanate, trimethylhexamethylene diisocyanate, hexamethylene diisocyanate, cyclohexane diisocyanate, methylcyclohexane diisocyanate, isophorone diisocyanate, methylene bis (4-cyclohexyl isocyanate), isopropylidene dicyclohexyl diisocyanate Ne Alicyclic isocyanates such as bets are exemplified. Further, polymers and derivatives such as burettes, isocyanurates, uretdiones, and carbodiimide modified products of these isocyanates are also included. These may be used alone or in combination. In addition, the isocyanate compound may be used alone, or may be used as a mixture or bond with various polymers.

The ratio of the metal oxide is usually 3 to 70% by weight, preferably 5 to 50% by weight, more preferably 5 to 40% by weight, and particularly preferably 8 to 30% by weight, as a ratio in the nonvolatile component of the coating solution. is there. When the amount of the metal oxide is less than 3% by weight, the refractive index of the primer layer cannot be made sufficiently high, so that interference unevenness may not be reduced. When it exceeds 70% by weight, the primer layer is transparent. Sexuality may worsen.

The proportion of the oxazoline compound is usually 1 to 50% by weight, preferably 1 to 30% by weight, and more preferably 3 to 20% by weight as a proportion in the nonvolatile component of the coating solution. If the amount is less than 1% by weight, there is a concern that the adhesion to the surface functional layer such as the hard coat layer may be reduced. If the amount exceeds 50% by weight, the refractive index of the primer layer is lowered, thereby causing a hard coat layer or the like. Visibility may not be good due to interference unevenness after the surface functional layer is formed.

The ratio of the epoxy compound is usually 1 to 50% by weight, preferably 3 to 30% by weight, and more preferably 5 to 20% by weight as a ratio in the nonvolatile component of the coating liquid. When it is out of these ranges, there is a possibility that the adhesion with the surface functional layer such as the hard coat layer may be lowered, or the coated surface state may be deteriorated.

When using a compound having a condensed polycyclic aromatic as a component of the coating solution, the ratio is selected as follows. That is, the proportion of the condensed polycyclic aromatic in the compound is usually 5 to 80% by weight, preferably 10 to 60% by weight as the proportion in the nonvolatile component of the coating solution. The ratio of the compound having a condensed polycyclic aromatic is usually 80% by weight or less, preferably 5 to 70% by weight, and more preferably 10 to 50% by weight as a ratio in the nonvolatile component of the coating solution. By using within these ranges, the refractive index of the primer layer can be easily adjusted, and interference unevenness after forming a surface functional layer such as a hard coat layer can be easily reduced. The ratio of the condensed polycyclic aromatic can be determined by, for example, dissolving and extracting the primer layer with an appropriate solvent or warm water, separating by chromatography, analyzing the structure by NMR or IR, and further pyrolyzing GC-MS (gas It can be determined by analyzing by chromatography mass spectrometry) or optical analysis.

The primer layer can be obtained, for example, by applying the above coating solution to a film, drying, and curing. The coating solution may contain other components such as a binder polymer.

The obtained primer layer is considered to react at an appropriate ratio depending on the heating conditions of the oxazoline compound and the epoxy compound. When each component compound is not completely reacted, both the unreacted product and the reaction product of each component are included in an arbitrary ratio.

These heat-reactive compounds may be used in combination to increase the strength of the primer layer or improve water resistance, but a strong coating layer may usually have poor adhesion. However, in the present invention, extremely excellent adhesiveness can be obtained by using an oxazoline compound and an epoxy compound in combination.

(Primer layer in the second invention)
In the present invention, it is an essential requirement to have a primer layer formed from a coating liquid containing a metal oxide, a polyester resin containing a naphthalene skeleton, and an isocyanate compound on at least one side of the polyester film. .
In addition, about the effect and specific example of a metal oxide, it is the same as the metal oxide used with the primer layer in 2nd invention.

The polyester resin containing a naphthalene skeleton in the present invention is mainly used for adjusting the refractive index of the primer layer and improving the adhesion with a surface functional layer such as a hard coat layer.

Examples of a method for incorporating a naphthalene skeleton into a polyester resin include, for example, introducing two or more hydroxyl groups as substituents into a naphthalene ring to form a diol component or a polyvalent hydroxyl component, or two or more carboxylic acid groups. There is a method of introducing a dicarboxylic acid component or a polyvalent carboxylic acid component. From the viewpoint of the stability of the polyester resin, it is preferable to introduce a carboxylic acid group into the naphthalene ring to form an acid component. Representative examples of the naphthalene skeleton introduced with a carboxylic acid group include 2,6-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, and 2,7-naphthalenedicarboxylic acid. Of these, 2,6-naphthalenedicarboxylic acid is particularly preferred.

Further, as a constituent component of the polyester resin containing a naphthalene skeleton, for example, a polyvalent carboxylic acid and a polyvalent hydroxy compound having no naphthalene skeleton as described below may be used in combination. That is, as the polyvalent carboxylic acid, terephthalic acid, isophthalic acid, orthophthalic acid, phthalic acid, 4,4′-diphenyldicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 2-potassium sulfoterephthalic acid, 5-sodium sulfone Isophthalic acid, adipic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, glutaric acid, succinic acid, trimellitic acid, trimesic acid, pyromellitic acid, trimellitic anhydride, phthalic anhydride, p-hydroxybenzoic acid, trimellitic acid Acid monopotassium salts and ester-forming derivatives thereof can be used. Examples of polyvalent hydroxy compounds include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, and 1,3-propanediol. 1,4-butanediol, 1,6-hex Diol, 2-methyl-1,5-pentanediol, neopentyl glycol, 1,4-cyclohexanedimethanol, p-xylylene glycol, bisphenol A-ethylene glycol adduct, Diethylene glycol, triethylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polytetramethylene oxide glycol, dimethylolpropionic acid, glycerin, trimethylolpropane, sodium dimethylolethylsulfonate And potassium dimethylolpropionate.

The isocyanate compound in the present invention mainly improves the adhesion with a surface functional layer such as a hard coat layer, and further strengthens the primer layer and has durability against various solvents used when forming the surface functional layer. It is used to improve. In the present invention, adjustment of the refractive index is important, and therefore, an aromatic isocyanate compound that can be designed to have a refractive index higher than that of an aliphatic or alicyclic isocyanate compound is preferable.

The isocyanate compound is an isocyanate or an isocyanate derivative typified by blocked isocyanate, and a compound produced as a result of reaction of these isocyanate groups during the formation of the primer layer. Preferred examples of the isocyanate include tolylene diisocyanate, xylylene diisocyanate, methylene diphenyl diisocyanate, phenylene diisocyanate, and naphthalene diisocyanate. Among these, tolylene diisocyanate is particularly preferable from the viewpoint of adhesion.

When used in the state of blocked isocyanate, the blocking agent includes, for example, bisulfites, phenolic compounds such as phenol, cresol, and ethylphenol, and alcohols such as propylene glycol monomethyl ether, ethylene glycol, benzyl alcohol, methanol, and ethanol. Compounds, active methylene compounds such as dimethyl malonate, diethyl malonate, methyl acetoacetate, ethyl acetoacetate and acetylacetone, mercaptan compounds such as butyl mercaptan and dodecyl mercaptan, lactam compounds such as ε-caprolactam and δ-valerolactam , Amine compounds such as diphenylaniline, aniline, ethyleneimine, acetanilide, acid amide compounds of acetic acid amide, formaldehyde, acetal Examples include oxime compounds such as dooxime, acetone oxime, methyl ethyl ketone oxime, and cyclohexanone oxime, and these may be used alone or in combination of two or more.

Further, the isocyanates described above or isocyanate derivatives typified by blocked isocyanates may be used alone, or may be used as a mixture or combination with various polymers.

In the laminated polyester film of the present invention, for improving the coated surface, reducing interference unevenness when various surface functional layers such as a hard coat layer are laminated on the coated surface, improving transparency and adhesion, etc. It is also possible to use various polymers in combination.

Specific examples of the polymer include polyester resin not containing naphthalene skeleton, acrylic resin, urethane resin, polyvinyl (polyvinyl alcohol, polyvinyl chloride, vinyl chloride vinyl acetate copolymer, etc.), polyalkylene glycol, polyalkyleneimine, methylcellulose, Examples include hydroxy cellulose and starches. Among these, polyester resins, acrylic resins, and urethane resins that do not contain a naphthalene skeleton are preferable from the viewpoint of improving adhesion to a surface functional layer such as a hard coat layer.

Furthermore, a crosslinking agent other than the isocyanate compound may be used in combination as long as the gist of the present invention is not impaired. Various known resins can be used as the crosslinking agent, and examples thereof include melamine compounds, oxazoline compounds, epoxy compounds, carbodiimide compounds, and the like.

In the polyester resin containing a naphthalene skeleton that can be used in the coating solution for forming the primer layer constituting the laminated polyester film in the present invention, the proportion of the naphthalene ring in the compound is usually 5 to 80% by weight, preferably 10%. ~ 60% by weight. The proportion of the polyester resin containing a naphthalene skeleton in the whole primer layer is usually 5 to 90% by weight, preferably 10 to 85% by weight, more preferably 15 to 80% by weight as a proportion in the nonvolatile component of the coating solution. %. By using within these ranges, the refractive index of the primer layer can be easily adjusted, and interference unevenness after forming a surface functional layer such as a hard coat layer can be easily reduced. The ratio of the naphthalene ring can be determined by, for example, dissolving and extracting the primer layer with an appropriate solvent or warm water, fractionating by chromatography, analyzing the structure by NMR or IR, and further pyrolysis GC-MS (gas chromatography mass spectrometry) ) Or optical analysis.

The proportion of the metal oxide used in the coating solution for forming the primer layer constituting the laminated polyester film in the present invention is usually 3 to 70% by weight, preferably 5 to 50% by weight, as a proportion in the nonvolatile components of the coating solution. More preferably, it is 5 to 40% by weight, particularly preferably 6 to 30% by weight. When the amount of the metal oxide is less than 3% by weight, the refractive index of the primer layer cannot be made sufficiently high, so that interference unevenness may not be reduced. When it exceeds 70% by weight, the primer layer is transparent. The adhesiveness may deteriorate or the adhesiveness may decrease.

The ratio of the compound derived from the aromatic isocyanate compound used in the coating liquid for forming the primer layer constituting the laminated polyester film in the present invention is usually 1 to 50% by weight, preferably 5% as a ratio in the non-volatile component of the coating liquid. -40% by weight, more preferably 10-30% by weight. When the amount is less than 1% by weight, there is a concern that the adhesion to the surface functional layer such as a hard coat layer may be reduced, or that the heat and humidity resistance may be lowered due to the weak primer layer. When the refractive index of the primer layer is lowered, the visibility may not be good due to uneven interference after the surface functional layer such as the hard coat layer is formed.

The primer layer can be obtained, for example, by applying the above coating solution to a film, drying, and curing. The coating solution may contain other components such as a binder polymer.

The obtained primer layer is considered to have reacted at an appropriate ratio depending on the heating conditions of the isocyanate compound. When each component compound is not completely reacted, both the unreacted product and the reaction product of each component are included in an arbitrary ratio.

These heat-reactive compounds may be used in combination to increase the strength of the primer layer or improve water resistance, but a strong coating layer may usually have poor adhesion. However, in the present invention, extremely excellent adhesiveness can be obtained by using an isocyanate compound.

(Common items of the first invention and the second invention)

In the present invention, the primer layer preferably contains particles other than the above-described metal oxide for the purpose of improving the adhesion and slipperiness of the primer layer. In particular, in the case of a design that does not contain particles in the polyester film, in order to improve the handleability such as the slipperiness of the film, the design that contains particles larger than the particle size of the metal oxide particles described above in the primer layer It is preferable to make it. The average particle size of the particles contained in the primer layer used for this purpose is usually 1.0 μm or less, preferably 0.05 to 0.7 μm, and more preferably 0.1 to 0.1 μm from the viewpoint of film transparency. 0.5 μm. Specific examples of the particles include silica, alumina, kaolin, calcium carbonate, and organic particles, and silica is particularly preferable from the viewpoint of dispersibility.

In the present invention, the ratio of the particles that can be contained in the coating liquid for forming the primer layer and used for improving the handleability such as the slipperiness of the film is usually 0 as the ratio in the nonvolatile component of the coating liquid. 0.1 to 5% by weight, preferably 0.3 to 3% by weight, more preferably 0.4 to 2% by weight. If the amount is small, it is necessary to improve the effect of the metal oxide particles contained in the coating solution for forming the primer layer or the particles to be included in the film. Sex worsens.

In the range not impairing the gist of the present invention, an appropriate amount of a known anionic surfactant or nonionic surfactant can be added in order to improve the wettability to the film and coat the coating solution uniformly. is there. In order to improve the wettability to the film, a fluorosurfactant is more preferably used.

Fluorosurfactant refers to a compound having a hydrocarbon chain in which some or all of the hydrogen atoms are substituted with fluorine atoms. When an aqueous coating solution is used, the fluorosurfactant preferably has a certain degree of water solubility or water dispersibility. For example, a compound having a hydrophilic group in addition to a fluorine-substituted hydrocarbon chain is used. Can be mentioned. Examples of the hydrophilic group include amines or metal salts such as sulfonic acid, carboxylic acid, and phosphoric acid, halogenated salts of tertiary amines, hydroxyl groups, and ether groups.

Examples of the anionic fluorosurfactant include lithium salt, potassium salt, sodium salt and ammonium salt of perfluoroalkyl (C4 to C12) sulfonic acid, potassium salt of perfluoroalkyl (C7 to C20) carboxylic acid, sodium Salts, ammonium salts, perfluoroalkyl dicarboxylic acid potassium salts, perfluoroalkyl phosphates and the like. Nonionic fluorosurfactants include perfluorooctanesulfonic acid diethanolamide, N-propyl-N- (2-hydroxyethyl) perfluorooctanesulfonic acid amide, perfluoroalkylpolyoxyethylene ethanol, perfluoro Examples include alkyl alkoxylates.

Furthermore, as long as the gist of the present invention is not impaired, the primer layer may include an antifoaming agent, a thickener, an organic lubricant, an antistatic agent, an ultraviolet absorber, an antioxidant, a foaming agent, a dye, and a pigment as necessary. Etc. may be contained.

In the polyester film of the present invention, the primer layer 2 can also be provided on the surface opposite to the surface provided with the primer layer. For example, when forming a functional layer such as a microlens layer, a prism layer, an anti-sticking layer, a light diffusion layer, a hard coat layer, an adhesive layer, or a print layer on the opposite side of forming a surface functional layer such as a hard coat layer, Adhesion with the functional layer can be improved. A conventionally well-known thing can be used as a component of the primer layer 2 formed in the surface on the opposite side. Examples thereof include binder polymers such as polyester resins, acrylic resins and urethane resins, cross-linking agents such as oxazoline compounds, epoxy compounds, melamine compounds and isocyanate compounds, and these materials may be used alone or in combination. May be used in combination. Moreover, the primer layer 2 (the same primer layer on both sides of the polyester film) containing the metal oxide, the oxazoline compound, and the epoxy compound as described above may be used.

The analysis of the components in the primer layer can be performed, for example, by analysis of TOF-SIMS, ESCA, fluorescent X-rays and the like.

When providing a primer layer by in-line coating, apply the above-mentioned series of compounds as an aqueous solution or water dispersion and apply a coating solution adjusted to a non-volatile component concentration of about 0.1 to 50% by weight on the polyester film. It is preferable to produce a laminated polyester film. Moreover, in the range which does not impair the main point of this invention, a small amount of organic solvents may be contained in the coating liquid for the purpose of improving dispersibility in water, improving film-forming properties, and the like. Only one type of organic solvent may be used, or two or more types may be used as appropriate.

Regarding the laminated polyester film in the present invention, the thickness of the primer layer provided on the polyester film is usually 0.04 to 0.20 μm, preferably 0.07 to 0.15 μm. When the film thickness is out of the above range, visibility may deteriorate due to interference unevenness after the surface functional layer is laminated.

In the present invention, the primer layer may be provided by a conventionally known coating method such as reverse gravure coating, direct gravure coating, roll coating, die coating, bar coating, curtain coating or the like.

In the present invention, the drying and curing conditions for forming the primer layer on the polyester film are not particularly limited. For example, when the primer layer is provided by off-line coating, usually at 80 to 200 ° C. for 3 to 40 seconds. The heat treatment is preferably performed at 100 to 180 ° C. for 3 to 40 seconds as a guide.

On the other hand, when the primer layer is provided by in-line coating, it is usually preferable to perform heat treatment at 70 to 280 ° C. for 3 to 200 seconds as a guide.

In addition, regardless of off-line coating or in-line coating, heat treatment and active energy ray irradiation such as ultraviolet irradiation may be used in combination as necessary. The polyester film constituting the laminated polyester film in the present invention may be subjected to surface treatment such as corona treatment or plasma treatment in advance.

The primer layer in the present invention has been adjusted in refractive index to suppress the occurrence of interference unevenness, and the refractive index is in the vicinity of the geometric mean of the surface functional layer such as the polyester film of the substrate and the hard coat layer. Designed. The refractive index of the primer layer and the reflectance of the primer layer are closely related. For the absolute reflectance of the present invention, a graph showing the wavelength on the horizontal axis and the reflectance on the vertical axis is drawn, and the minimum value of the reflectance is preferably one in the wavelength range of 400 to 800 nm, and the minimum value is 4 0.0% or more. In the absolute reflectance range of the present invention, if the minimum value appears at the same wavelength, the reflectance of the minimum value is a high value when the refractive index is high, and a low value when the refractive index is low.

In the present invention, the absolute reflectance usually has one minimum value in the wavelength range of 400 to 800 nm, more preferably one minimum value in the wavelength range of 500 to 700 nm. The minimum value is preferably in the range of 4.0 to 6.5%, more preferably 4.5 to 6.2%. If the minimum value in the wavelength range of 400 to 800 nm is not one, and if the absolute reflectance of the minimum value deviates from the above value, interference unevenness occurs after the surface functional layer such as a hard coat layer is formed. In some cases, the designability may deteriorate.

The polyester film of the present invention is generally provided with a surface functional layer such as a hard coat layer on the primer layer. Although it does not specifically limit as a material used for a hard-coat layer, For example, hardened | cured materials, such as reactive silicon compounds, such as monofunctional (meth) acrylate, polyfunctional (meth) acrylate, and tetraethoxysilane, are mentioned. Among these, from the viewpoint of achieving both productivity and hardness, a polymerization cured product of a composition containing an ultraviolet curable polyfunctional (meth) acrylate is particularly preferable.

The composition containing an ultraviolet curable polyfunctional (meth) acrylate is not particularly limited. For example, a mixture of one or more known ultraviolet curable polyfunctional (meth) acrylates, those commercially available as ultraviolet curable hard coat materials, or the range that does not impair the purpose of this embodiment other than these, What added the other component further can be used.

The UV-curable polyfunctional (meth) acrylate is not particularly limited. For example, dipentaerythritol hexa (meth) acrylate, tetramethylolmethanetetra (meth) acrylate, tetramethylolmethanetri (meth) acrylate, (Meth) acryl derivatives of polyfunctional alcohols such as trimethylolpropane tri (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,6-bis (3-acryloyloxy-2-hydroxypropyloxy) hexane And polyethylene glycol di (meth) acrylate and polyurethane (meth) acrylate.

Other components contained in the composition containing an ultraviolet curable polyfunctional (meth) acrylate are not particularly limited. Examples thereof include inorganic or organic fine particles, polymerization initiators, polymerization inhibitors, antioxidants, antistatic agents, dispersants, surfactants, light stabilizers and leveling agents. In addition, when the film is dried after film formation in the wet coating method, an arbitrary amount of solvent can be added.

As a method for forming the hard coat layer, when an organic material is used, a general wet coat method such as a roll coat method or a die coat method is employed. The formed hard coat layer can be subjected to a curing reaction by heating, irradiation with active energy rays such as ultraviolet rays and electron beams as necessary.

Any adhesive can be used for bonding the decorative plate or the polyester film for decorative sheets of the present invention to the substrate. Examples of adhesives include urea resin adhesives, melamine resin adhesives, phenol resin adhesives, α-olefin resin adhesives, adhesives based on a mixture of aqueous polymer and isocyanate, epoxy adhesives, solution type Vinyl acetate resin adhesive, emulsion type vinyl acetate resin adhesive, acrylic emulsion adhesive, hot melt adhesive, cyanoacrylate adhesive, polyurethane adhesive, chloroprene rubber adhesive, nitrile rubber adhesive, SBR adhesives, modified rubber emulsion adhesives, ethylene copolymer resin adhesives, resorcin adhesives, natural rubber adhesives, cellulose adhesives, starch pastes, dextrins, and the like.

When the base material is wood, urea resin adhesive, melamine resin adhesive, α-olefin resin adhesive, adhesive based on a mixture of aqueous polymer and isocyanate, emulsion type vinyl acetate resin adhesive, acrylic emulsion system Adhesives, chloroprene rubber adhesives, modified rubber emulsion adhesives, and cellulose adhesives are mainly used.

Examples of commercially available urea resin adhesives include "Euroid 310", "Euroid 320", "Euroid 701", "Euroid 755", and "Euroid 730" manufactured by Mitsui Toatsu Chemical Co., Ltd. Commercially available melamine resin adhesives include, for example, “Euroid 350”, “Euroid 775”, “Euroid 781”, “Structbond C-1”, “Structbond C-10” (manufactured by Mitsui Toatsu Chemical Co., Ltd.) As described above, melamine / urea resin), “Euroid 883” manufactured by Mitsui Toatsu Chemical Co., Ltd., “Euroid 811” (above, melamine / phenol resin) and the like can be mentioned.

Commercially available phenolic resin adhesives include, for example, “Euroid PL-261”, “Euroid PL-281”, “Euroid PL-211”, “Euroid PL-222” manufactured by Mitsui Toatsu Chemicals, manufactured by Konishi "PR22" etc. are mentioned. Examples of commercially available α-olefin resin adhesives include “SH2”, “SH3”, “SH5W”, “SH6”, “SH20”, and “SH20L2” manufactured by Konishi. Examples of commercially available adhesives made of a mixture of an aqueous polymer and an isocyanate include “CU1”, “CU5”, and “CU51” manufactured by Konishi.

Commercially available epoxy adhesives include, for example, “Sdyne 3008”, “Sdyne 3200”, “Sdyne 3710”, “Sdyne 3730”, “Esdyne 3740”, “Sdyne 3750”, “Sdyne 3600” manufactured by Sekisui Chemical Co., Ltd. ”,“ Esdyne 3611 ”,“ Esdyne 3450 ”, and the like. Examples of commercially available solvent-type vinyl acetate resin adhesives include “ESDINE 1011”, “ESDINE 1013”, “ESDINE 1015”, “ESDINE 1020”, and “ESDINE 1057” manufactured by Sekisui Chemical Co., Ltd.

Commercially available emulsion type vinyl acetate resin adhesives include, for example, “656”, “605”, “EM-65”, “EM-90”, “602 (T)” manufactured by Cemedine, Sekisui Chemical Co., Ltd. “Esdyne 5100”, “Esdyne 5165”, “Esdyne 5200”, “Esdyne 5300”, “Esdyne 5301”, “Esdyne 5320”, “Esdyne 5400”, “Esdyne 5403”, “Esdyne 5405”, “Esdyne 5406” “Esdyne 5408”, “Esdyne 5410”, “Esdyne 5440”, “Esdyne 5500”, “Esdyne 5700”, “Esdyne 5800”, “Esdyne 5803”, “Esdyne 5815”, “CH2” manufactured by Konishi, "," CH3 "," CH5 "," CH 8 ”,“ CH20 ”,“ CH7 ”,“ CH7L ”,“ CH27 ”,“ CH1000 ”,“ CH63 ”,“ CH65 ”,“ CH131 ”,“ CH133 ”,“ CH115 ”,“ CX10 ”,“ CX55 ” , “CH1500”, “CH1600”, “CH3000L”, “CH72”, “CH73”, “CH74”, “CH77”, “CH107 with curing agent”, “PTS (A / B)”, “CH7000 / PTS7000” Etc.

Commercially available acrylic emulsion adhesives include, for example, “EM-315”, “EM-370A / B”, “Molecorn 685”, “EM-326”, “679”, “EM-702” manufactured by Cemedine. "CEL10", "CEL20", "CEL22", "CEL25N", "CEL60", "CEL63", "CVC33", "CVC36", "CVC36F", "CV3105 series", "SP65", manufactured by Konishi “SP85”, “SP200”, “SP210”, “SP220”, “SP281”, “SP285”, “SP290”, “SP291”, “SP3055”, “CN520”, “CZ100”, “CZ220”, “CE780” ”,“ CE801 ”,“ Nedabond A ”,“ Nedabond W1000 ”, and the like.

Examples of commercially available chloroprene rubber adhesives include “Sdyne 276AL”, “Esdyne 276FS”, “Esdyne 276M”, “Esdyne SG202D”, “Esdyne 278”, “Esdyne SG2005E” manufactured by Sekisui Chemical Co., Ltd., Konishi Co., Ltd. “G10”, “G11”, “G12”, “Super G Ace”, “G17”, “G18”, “G19”, “G5000”, “G5800”, “GS5”, “GU55 Blue”, “GU68F” “Green”, “G77”, “G78”, “Nedabond G”, “Super G Spray”, “GW150” and the like.

Examples of commercially available modified rubber emulsion adhesives include “CL-5N” and “CL-7N” manufactured by Cemedine, “FL200”, “FL105S”, “HB2”, and “HB10” manufactured by Konishi. It is done. Examples of commercially available resorcin-based adhesives include “KR15” manufactured by Konishi, and examples of commercially available cellulose-based adhesives include “work bond (K)” manufactured by Konishi.

Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following examples unless it exceeds the gist. The measurement method and evaluation method used in the present invention are as follows. Unless otherwise specified, “parts” in Examples and Comparative Examples means “parts by weight” and “%” means “% by weight”. Moreover, the symbols “A” and “B” attached to the numbers of the examples and comparative examples mean the examples and comparative examples relating to the first invention and the second invention, respectively.

(1) Measuring method of intrinsic viscosity of polyester:
1 g of polyester from which other polymer components and pigments incompatible with polyester were removed was precisely weighed, 100 ml of a mixed solvent of phenol / tetrachloroethane = 50/50 (weight ratio) was added and dissolved, and measurement was performed at 30 ° C.

(2) Measuring method of average particle diameter:
The primer layer was observed using TEM (H-7650 manufactured by Hitachi, Ltd., acceleration voltage 100 V), and the average value of the particle diameters of 10 particles was defined as the average particle diameter.

(3) Method for measuring the thickness of the primer layer:
The surface of the primer layer was stained with RuO ₄ and embedded in an epoxy resin. Thereafter, the section prepared by the ultrathin section method was stained with RuO ₄ , and the cross section of the primer layer was measured using TEM (“H-7650” acceleration voltage 100 V, manufactured by Hitachi, Ltd.).

(4) Evaluation method of absolute reflectance from primer layer surface in polyester film:
A black tape (vinyl tape “VT-50” manufactured by Nichiban Co., Ltd.) is pasted on the measurement back side of the polyester film in advance, and a spectrophotometer (UV-spectrophotometer “V-570” manufactured by JASCO Corporation) and an automatic absolute reflectance measuring device. "AM-500N") using synchronous mode, incident angle 5 °, N-polarized light, response fast, data acquisition interval 1.0 nm, bandwidth 10 nm, scanning speed 1000 m / min. The absolute reflectance was measured, and the wavelength (bottom wavelength) and reflectance at the minimum value were evaluated.

(5) Concealment degree (transmission density):
Using a Macbeth densitometer (TD-904 type), the transmitted light density under the G filter was measured. The larger this value, the higher the hiding power.

(6) Suitability of decorative board (change in printing color):
A case where a decorative sheet is pasted on a plywood, which is a flat base material with a black surface, to form a decorative board, and the color change of the design pattern printed on the surface of the decorative sheet is observed, and the design is maintained. The case where the change in color tone was remarkable and the designability was lowered was designated as C, and the middle thereof was designated as B.

(7) Interference unevenness evaluation method:
On the primer layer side of the polyester film, 72 parts by weight of dipentaerythritol hexaacrylate, 18 parts by weight of 2-hydroxy-3-phenoxypropyl acrylate, 10 parts by weight of antimony pentoxide, a photopolymerization initiator (trade name “Irgacure 184” Ciba Specialty A mixed coating solution of 1 part by weight of Chemicals Co., Ltd. and 200 parts by weight of methyl ethyl ketone was applied to a dry film thickness of 5 μm and cured by irradiating with ultraviolet rays to form a hard coat layer. The obtained film is visually observed under a three-wavelength light area type fluorescent lamp, and interference unevenness is observed. A when interference unevenness cannot be confirmed is A, when thin sparse interference unevenness is confirmed, B is thin but linear. The case where the interference unevenness was confirmed was C, and the case where the clear interference unevenness was confirmed was D.

(8) Hard coat layer adhesion evaluation method:
In order to evaluate the tighter adhesion, the materials obtained by removing antimony pentoxide from the hard coat liquid used in the evaluation of the above (5) were examined. That is, 80 parts by weight of dipentaerythritol hexaacrylate, 20 parts by weight of 2-hydroxy-3-phenoxypropyl acrylate, 5 parts by weight of a photopolymerization initiator (trade name “Irgacure 184” manufactured by Ciba Specialty Chemicals), 200 parts by weight of methyl ethyl ketone The mixed coating solution was applied so as to have a dry film thickness of 5 μm, and cured by irradiation with ultraviolet rays to form a hard coat layer. The obtained film was subjected to a 10 × 10 cross-cut after 100 hours in an environment of 80 ° C. and 90% RH, and a tape of 18 mm width (cello tape (registered trademark) “CT” manufactured by Nichiban Co., Ltd.) was formed thereon. -18 ") is applied, and the peeled surface is observed after abrupt peeling at a 180 degree peel angle. If the peel area is less than 3%, A is 3% or more and less than 10% B, 10% or more 50 If less than%, C, and if more than 50%, D.

The polyester used in the examples and comparative examples was prepared as follows.
<Method for producing polyester (A)>
Using 100 parts by weight of dimethyl terephthalate and 60 parts by weight of ethylene glycol as starting materials, 0.09 parts by weight of magnesium acetate tetrahydrate as a catalyst is placed in the reactor, the reaction start temperature is set to 150 ° C., and the methanol is distilled off gradually. The reaction temperature was raised to 230 ° C. after 3 hours, and the transesterification reaction was substantially completed after 4 hours. Next, 0.04 part by weight of ethyl acid phosphate was added to the reaction mixture, 0.04 part by weight of antimony trioxide was added, and a polycondensation reaction was carried out for 4 hours according to a conventional method. That is, the reaction temperature was gradually raised from 230 ° C. and finally reached 280 ° C., while the pressure was gradually reduced from normal pressure and finally 0.3 mmHg. After the start of the reaction, the reaction was stopped at a time corresponding to an intrinsic viscosity of 0.63 due to a change in stirring power of the reaction vessel, and the polymer was discharged under nitrogen pressure to form a chip to obtain a polyester (A). The intrinsic viscosity of the obtained polyester (A) was 0.63.

<Method for producing polyester (B)>
In the above polyester (A) production method, 0.04 part by weight of ethyl acid phosphate is added, and then 0.2 part by weight of silica particles dispersed in ethylene glycol having an average particle size of 1.6 μm is added. A polyester (B) was obtained using the same method as the production method of the polyester (A) except that 0.04 part by weight was added and the polycondensation reaction was stopped at a time corresponding to an intrinsic viscosity of 0.65. The intrinsic viscosity of the obtained polyester (B) was 0.65.

<Method for producing polyester (C)>
Starting from 100 parts by weight of dimethyl terephthalate and 60 parts by weight of ethylene glycol, 0.07 parts by weight of calcium acetate / monohydrate as a catalyst is taken in the reactor, the reaction start temperature is set to 150 ° C., and the methanol is distilled off gradually. The reaction temperature was raised to 230 ° C. after 4 and a half hours, and the transesterification reaction was substantially completed. Next, 0.04 part by weight of orthophosphoric acid was added to the reaction mixture, 0.035 part by weight of antimony trioxide was added, and a polycondensation reaction was carried out for 4 hours according to a conventional method. That is, the reaction temperature was gradually raised to finally 280 ° C., while the pressure was gradually reduced from normal pressure and finally 0.05 mmHg. About 4 hours after the start of the reaction, the reaction was stopped and chipped according to a conventional method to obtain a polyester (C). The intrinsic viscosity of the obtained polyester (C) was 0.75.

<Method for producing polyester (D)>
40 parts by weight of the above polyester (C) and 60 parts by weight of rutile titanium dioxide were melt-mixed in a twin-screw extruder according to a conventional method and then chipped to obtain a master batch polyester (D).

<Method for producing polyester (E)>
In addition to 40 parts by weight of the above polyester (C) and 60 parts by weight of rutile titanium dioxide, 3.5 parts by weight of anthraquinone, 0.1 parts by weight of carbon black and 2.0 parts by weight of iron oxide are used as a yellow pigment. According to a conventional method, the mixture was melt-mixed in a twin screw extruder and then chipped to obtain a masterbatch polyester (E).

Examples of compounds constituting the primer layer are as follows.
(Compound example)
Metal oxide: (IA) Zirconium oxide particles with an average particle diameter of 15 nm Metal oxide: (IB) Titanium oxide particles with an average particle diameter of 15 nm Metal oxide: (IC) Zirconium oxide particles with an average particle diameter of 70 nm Oxazoline Compound: (II (1) A)
Acrylic polymer “Epocross WS-500” having an oxazoline group and a polyalkylene oxide chain (manufactured by Nippon Shokubai Co., Ltd., containing about 38% by weight of 1-methoxy-2-propanol solvent)
・ Oxazoline compounds: (II (1) B)
Acrylic polymer “Epocross WS-700” having an oxazoline group and a polyalkylene oxide chain (manufactured by Nippon Shokubai Co., Ltd., VOC free type)

Epoxy compound: (III (1) A) polyglycerol polyglycidyl ether, Denacol EX-521 (manufactured by Nagase ChemteX Corporation).
Epoxy compound: (III (1) B) “Denacol EX-1410” (manufactured by Nagase ChemteX Corporation), which is an epoxy resin.
・ Polyester resin containing naphthalene skeleton: (II (2) A)
A water dispersion of a polyester resin copolymerized with the following composition: Monomer composition: (acid component) 2,6-naphthalenedicarboxylic acid / 5-sodium sulfoisophthalic acid // (diol component) ethylene glycol / diethylene glycol = 92/8 // 80 / 20 (mol%)
・ Polyester resin containing naphthalene skeleton: (II (2) B)
Water dispersion of polyester resin copolymerized with the following composition: Monomer composition: (acid component) 2,6-naphthalenedicarboxylic acid / terephthalic acid / 5-sodium sulfoisophthalic acid // (diol component) ethylene glycol / diethylene glycol = 78/15 / 7 // 90/10 (mol%)
・ Aromatic isocyanate compounds: (II (3))
100 parts by weight of polyester polyol (average molecular weight 1700) of adipic acid / isophthalic acid // 1,6-hexanediol = 50/50 // 100 (mol%) in methyl ethyl ketone solvent, 9 parts by weight of 1,4-butanediol After adding 80 parts by weight of tolylene diisocyanate to 8 parts by weight of trimethylolpropane and reacting, 12 parts by weight of dimethylolpropionic acid, 16 parts by weight of polyethylene glycol (average molecular weight 600), and an amine catalyst were added. The reaction was performed at 75 ° C. Next, 16 parts by weight of methyl ethyl ketone oxime was added at 55 ° C. to obtain a blocked isocyanate group-containing urethane prepolymer. Furthermore, the blocked aromatic isocyanate compound obtained by mixing 7.2 parts by weight of triethylamine and 450 parts by weight of water, adding 2.9 parts by weight of triethylenetetramine, causing the reaction to remove the methyl ethyl ketone solvent.
・ Condensed polycyclic aromatic polyester resin: (IVA)
Water dispersion of polyester resin copolymerized with the following composition: Monomer composition: (acid component) 2,6-naphthalenedicarboxylic acid / 5-sodium sulfoisophthalic acid // (diol component) ethylene glycol / diethylene glycol = 92/8 // 80/20 (mol%)

・ Polyester resin: (IVB)
Water dispersion of polyester resin copolymerized with the following composition: Monomer composition: (acid component) terephthalic acid / isophthalic acid / 5-sodium sulfoisophthalic acid // (diol component) ethylene glycol / 1,4-butanediol / diethylene glycol = 56/40/4 // 70/20/10 (mol%)
Acrylic resin: (IVC) Aqueous dispersion of acrylic resin polymerized with the following composition: ethyl acrylate / n-butyl acrylate / methyl methacrylate / N-methylol acrylamide / acrylic acid = 65/21/10/2/2 (% by weight) Emulsion polymer (emulsifier: anionic surfactant)
・ Urethane resin (IVD)
"Hydran AP-40", a carboxylic acid water-dispersed polyester polyurethane resin (manufactured by DIC)
・ Hexamethoxymethylmelamine (V)
Particles: (VIA) Silica particles with an average particle size of 0.07 μm Particles: (VIB) Silica particles with an average particle size of 0.12 μm Particles: (VIC) Silica particles with an average particle size of 0.45 μm Particles: (VID ) Silica particles / particles with an average particle size of 0.30 μm: (VIE) Silica particles with an average particle size of 0.16 μm

Example 1A:
A mixed raw material in which polyesters (A) and (B) are mixed at a ratio of 90% and 10%, respectively, is used as an outermost layer raw material, and a mixed raw material in which polyesters (C) and (D) are mixed at a ratio of 88% and 12%, respectively. Was fed to two extruders, melted at 285 ° C., and then two kinds of 3 layers (surface layer / intermediate layer / surface layer = 6 / (Extruded amount of 38/6) was co-extruded and cooled and solidified to obtain an unstretched sheet. Next, using the roll peripheral speed difference, the film was stretched 3.0 times in the machine direction at a film temperature of 83 ° C., and then the coating solution 1 shown in Table 1 below was applied to both sides of the longitudinally stretched film, leading to a tenter. The film was stretched 3.2 times at 125 ° C. in the transverse direction and heat-treated at 215 ° C. to obtain a biaxially oriented polyester film having a thickness of 50 μm having a primer layer having a thickness of 0.10 μm (after drying). The film after laminating the hard coat layer on the obtained polyester film has no clear interference unevenness and good adhesion, and the properties of this film are shown in Table 2 below.

Example 2A-21A:
In Example 1A, a polyester film was obtained in the same manner as in Example 1A except that the coating composition was changed to the coating composition shown in Table 1 below. As shown in Table 2 below, the obtained polyester film had a high reflectance, had good interference unevenness level after laminating the hard coat layer, and had good adhesion.

Example 22A:
In Example 1A, a biaxially oriented polyester film was obtained in the same manner as Example 1A, except that polyester (E) was used instead of polyester (D). As shown in Table 2 below, the obtained polyester film had a high reflectance, had good interference unevenness level after laminating the hard coat layer, and had good adhesion.

Comparative Examples 1A-5A:
In Example 1A, a polyester film was obtained in the same manner as in Example 1A except that the coating composition was changed to the coating composition shown in Table 1 below. When the obtained laminated polyester film was evaluated, as shown in Table 2 below, when clear interference unevenness could be observed after laminating the hard coat layer, the case where the adhesion was poor was observed.

Comparative Example 6A:
In Example 1A, a biaxially oriented polyester film was obtained in the same manner as in Example 1A, except that a mixed raw material in which polyesters (C) and (D) were mixed at a ratio of 99% and 1%, respectively, was used. As shown in Table 2 below, the obtained polyester film had high reflectance, good interference unevenness level after laminating the hard coat layer, and good adhesion, but the print color change was large. The suitability of the decorative board was insufficient.

Example 1B:
A mixed raw material in which polyesters (A) and (B) are mixed at a ratio of 90% and 10%, respectively, is used as an outermost layer raw material, and a mixed raw material in which polyesters (C) and (D) are mixed at a ratio of 88% and 12%, respectively. Was fed to two extruders, melted at 285 ° C., and then two kinds of 3 layers (surface layer / intermediate layer / surface layer = 6 / (Extruded amount of 38/6) was co-extruded and cooled and solidified to obtain an unstretched sheet. Next, the film was stretched 3.0 times in the machine direction at a film temperature of 83 ° C. using the roll peripheral speed difference, and then the coating solution 1 shown in Table 3 below was applied to both surfaces of the longitudinally stretched film, which was led to a tenter. The film was stretched 3.2 times at 125 ° C. in the transverse direction and heat-treated at 215 ° C. to obtain a biaxially oriented polyester film having a thickness of 50 μm having a primer layer having a thickness of 0.10 μm (after drying). The film after laminating the hard coat layer on the obtained polyester film had no clear interference unevenness and good adhesion, and the properties of this film are shown in Table 4 below.

Example 1B-18B:
In Example 1B, a polyester film was obtained in the same manner as in Example 1B except that the coating composition was changed to the coating composition shown in Table 3 below. The resulting polyester film had high reflectance, good interference unevenness level, and good adhesion as shown in Table 4 below.

Example 19B:
In Example 1B, a polyester film was obtained in the same manner as in Example 1B except that the outermost layer was made of polyester (A) alone. As shown in Table 4 below, the obtained polyester film had a high reflectance, had good interference unevenness level after laminating the hard coat layer, and had good adhesion.

Example 20B:
In Example 19B, a polyester film was obtained in the same manner as in Example 1B except that the coating composition was changed to the coating composition shown in Table 3 below. As shown in Table 4 below, the obtained polyester film had a high reflectance, had good interference unevenness level after laminating the hard coat layer, and had good adhesion.

Example 21B:
In Example 1B, a biaxially oriented polyester film was obtained in the same manner as in Example 1B, except that polyester (E) was used instead of polyester (D). As shown in Table 4 below, the obtained polyester film had a high reflectance, had good interference unevenness level after laminating the hard coat layer, and had good adhesion.

Comparative Examples 1B-5B:
In Example 1B, a polyester film was obtained in the same manner as in Example 1B except that the coating composition was changed to the coating composition shown in Table 3 below. When the obtained laminated polyester film was evaluated, as shown in Table 4 to be described later, when clear interference unevenness could be observed, there was a case where adhesion was inferior.

Comparative Example 6B:
In Example 1B, a biaxially oriented polyester film was obtained in the same manner as in Example 1B, except that a mixed raw material in which polyesters (C) and (D) were mixed at a ratio of 99% and 1%, respectively, was used as a raw material. As shown in Table 4 below, the obtained polyester film had high reflectivity, good interference unevenness level after laminating the hard coat layer, and good adhesion, but the print color change was large. The suitability of the decorative board was insufficient.

The film of the present invention can be suitably used, for example, as a film for a decorative board or a decorative sheet in which interference unevenness is not a concern.

Claims (4)

1. A polyester film used for the film layer of a decorative board or decorative sheet in which at least a film layer and a hard coat layer are sequentially arranged on the surface of a substrate, wherein the transmission density of the polyester film is 0.1 to 5 A laminated polyester film having a primer layer formed of a coating solution containing a metal oxide, an oxazoline compound, and an epoxy compound on at least one surface on which a hard coat layer is disposed.
2. The proportion of the metal oxide in the coating liquid is 3 to 70% by weight, the proportion of the oxazoline compound is 1 to 50% by weight, and the proportion of the epoxy compound is 1 to 50% by weight. Laminated polyester film.
3. A polyester film used for the film layer of a decorative board or decorative sheet in which at least a film layer and a hard coat layer are sequentially arranged on the surface of a substrate, wherein the transmission density of the polyester film is 0.1 to 5 And a primer layer formed from a coating liquid containing a metal oxide, a polyester resin containing a naphthalene skeleton, and an isocyanate compound on at least one surface on which a hard coat layer is disposed. the film.
4. The proportion of the coating liquid in the nonvolatile component is 3 to 70% by weight of the metal oxide, 5 to 90% by weight of the polyester resin containing a naphthalene skeleton, and 1 to 50% by weight of the isocyanate compound. The laminated polyester film according to claim 3.