JP2013199047A - Multilayer polyester film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyester film having a coating layer, which cuts ultraviolet rays and has all of excellent antistatic properties, easy adhesiveness and adhesion weatherability, and to provide another polyester film for decorative films.SOLUTION: A multilayer polyester film is obtained by forming the coating layer on at least one side of the polyester film. The coating layer is formed from a coating liquid containing: an acrylic resin having a reactive emulsifying agent-derived hydrophilic group in one molecule thereof; an oxazoline compound; and a compound having a quaternary ammonium group. The multilayer polyester film exhibits ≤5% light transmittance to a light beam having 380 nm wavelength. The polyester film for decorative films is obtained by forming a slightly tacky-adhesive layer on at least one side of the multilayer polyester film.

Description

  The present invention relates to a laminated polyester film, and more particularly to a polyester film for decorative film that cuts ultraviolet rays and has both excellent antistatic performance and easy adhesion performance.

Biaxially stretched polyester film excels in transparency, dimensional stability, mechanical properties, heat resistance, electrical properties, gas barrier properties, chemical resistance, etc., packaging materials, plate making materials, display materials, transfer materials, building materials, It is used for window paste materials, membrane switches, antireflection films used for flat displays, optical films such as diffusion sheets and prism sheets, and transparent touch panels. However, when other materials are applied and laminated on the polyester film in such applications, there is a drawback that the adhesiveness is poor depending on the materials used.
As one of the methods for improving the adhesiveness of the biaxially stretched polyester film, there is known a method of applying various resins to the surface of the polyester film and providing a coating layer having easy adhesion performance (Patent Documents 1 and 2). .

  However, such an existing easily-adhesive coating layer may still not have sufficient adhesion depending on the type of the topcoat layer. For example, when a so-called solventless UV curable coating is used as the topcoat, the solventless topcoat has a low penetration and swelling effect on the easy-adhesion layer compared to the solvent-based topcoat, and therefore has poor adhesion. It tends to be enough.

  For these problems, for example, by providing an easy-adhesion layer having a specific composition, a method of imparting better adhesiveness has been proposed and improved (Patent Documents 3 to 5).

  Recently, however, for decorative films based on polyester films, when used outdoors for long-term POPs at convenience stores, pharmacies, etc., not only adhesiveness but also long-term adhesive weather resistance performance. It has been demanded.

  Decorative films are widely used in a configuration where a polyester film substrate is provided with a slightly adhesive layer on one side and a printed layer or hard coat layer on the other side. It is known to provide a silicone-based micro-adhesive layer that can be pasted and peeled off many times, but in decorative films for window displays etc. in the outdoors or indoors exposed to direct sunlight, When re-peeling, there is a problem that the trace of the adhesive layer remains. In particular, when the adherend is glass, it becomes a significant problem (Patent Document 6).

  In addition, polyester film is easily charged during friction, peeling, etc., and when applying a silicone coating solution, there is a problem of uneven coating due to charging of the base material. There is also a demand for imparting antistatic performance.

  Therefore, a coating layer having adhesion weather resistance and antistatic properties as described above is required, but any conventional easy adhesion coating layer and easy adhesion coating layer having antistatic properties still have sufficient effects. It is not done.

JP-A-2002-53687 Japanese Patent Laid-Open No. 11-286092 JP 2009-220376 A JP 2009-221359 A JP 2010-13550 A JP 2007-254565 A

  The present invention has been made in view of the above circumstances, and a solution to the problem is a polyester film having a coating layer that cuts ultraviolet rays and has both excellent antistatic property, easy adhesion property, and adhesion weather resistance, and a decorative film It is to provide a polyester film.

  As a result of intensive studies on the above problems, the present inventors have found that the above problems can be solved by providing a specific polyester film with a coating layer containing a specific type of compound. It came to complete.

  That is, the gist of the present invention is a laminated polyester film having a coating layer on at least one side of the polyester film, the coating layer having an acrylic resin having a hydrophilic group derived from a reactive emulsifier in the molecule, and an oxazoline compound. A laminated polyester film formed from a coating solution containing a compound having a quaternary ammonium group, wherein the laminated polyester film has a light transmittance of 380 nm of 5% or less, and the laminated polyester film It exists in the polyester film for decorative films characterized by having a slightly adhesion layer on at least one side.

  ADVANTAGE OF THE INVENTION According to this invention, the polyester film which has the coating layer excellent in ultraviolet-cut property and excellent in antistatic property and easy-adhesion with respect to topcoat can be provided, and the industrial value of this invention is high.

The base film used in the present invention is made of polyester. Such polyesters include dicarboxylic acids such as terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, adipic acid, sebacic acid, 4,4′-diphenyldicarboxylic acid, 1,4-cyclohexyldicarboxylic acid or esters thereof. It is a polyester produced by melt polycondensation with glycols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,4-butanediol, neopentyl glycol, and 1,4-cyclohexanedimethanol. Polyesters composed of these acid components and glycol components can be produced by arbitrarily using a commonly used method.
For example, a transesterification reaction between a lower alkyl ester of an aromatic dicarboxylic acid and a glycol, or a direct esterification of an aromatic dicarboxylic acid and a glycol, to form a substantially bisglycol of an aromatic dicarboxylic acid A method is employed in which an ester or a low polymer thereof is formed and then polycondensed by heating under reduced pressure. Depending on the purpose, an aliphatic dicarboxylic acid may be copolymerized.

  Typical examples of the polyester of the present invention include polyethylene terephthalate, polyethylene-2,6-naphthalate, poly-1,4-cyclohexanedimethylene terephthalate, and the like. It may be a polymerized polyester and may contain other components and additives as necessary.

  The polyester film in the present invention can contain particles for the purpose of ensuring the film runnability and preventing scratches. Examples of such particles include inorganic particles such as silica, calcium carbonate, magnesium carbonate, calcium phosphate, kaolin, talc, aluminum oxide, titanium oxide, alumina, barium sulfate, calcium fluoride, lithium fluoride, zeolite, and molybdenum sulfide. Further, organic particles such as crosslinked polymer particles and calcium oxalate, and precipitated particles during the polyester production process can be used.

  The film of the present invention has an internal haze of usually 1.5% or less, preferably 1.0% or less. When the internal haze exceeds 1.5%, the transparency tends to be inferior, and thus visibility may be impaired.

  The particle size and content of the particles used are selected according to the use and purpose of the film, but the average particle size is usually in the range of 0.01 to 5.0 μm. If the average particle size exceeds 5.0 μm, the surface roughness of the film becomes too rough, or the particles are likely to fall off from the film surface. When the average particle size is less than 0.01 μm, the surface roughness is too small and sufficient slipperiness may not be obtained. The particle content can be adjusted within the range if the internal haze is 1.5% or less.

  In addition, when it is particularly desired to ensure the transparency and smoothness of the film, the film may be substantially free of particles. Further, various stabilizers, lubricants, antistatic agents and the like can be appropriately added to the film.

  As a film forming method of the film of the present invention, a generally known film forming method can be adopted, and there is no particular limitation. For example, a sheet obtained by melt extrusion is first stretched 2 to 6 times at 70 to 145 ° C. by a roll stretching method to obtain a uniaxially stretched polyester film, and then perpendicular to the previous stretching direction in the tenter. A film is obtained by extending | stretching 2 to 6 times at 80-160 degreeC to the direction, and also heat-processing at 150-250 degreeC for 1 to 600 seconds. Further, at this time, a method of relaxing 0.1 to 20% in the longitudinal direction and / or the transverse direction in the heat treatment zone and / or the cooling zone at the heat treatment outlet is preferable.

  The polyester film in the present invention has a single layer or multilayer structure. In the case of a multilayer structure, the surface layer and the inner layer, or both the surface layer and each layer can be made of different polyesters depending on the purpose.

  The polyester film of the present invention has a coating layer on at least one surface, but even if a similar or other coating layer or functional layer is provided on the opposite surface of the film, it is naturally included in the concept of the present invention.

  The film of the present invention contains an ultraviolet absorber in an amount of usually 0.20 to 10.0% by weight, preferably 0.30 to 1.8% by weight. When the ultraviolet absorber is less than 0.10% by weight, the polyester film may be deteriorated by ultraviolet rays. When the ultraviolet absorber is contained in an amount exceeding 10.0% by weight, the ultraviolet absorber is bleeded on the surface. May cause deterioration of surface functionality such as adhesion loss.

  The film of the present invention has a light transmittance at a wavelength of 380 nm of 5.0% or less, preferably 2.0% or less, more preferably 1.0% or less. When the light transmittance at a wavelength of 380 nm is larger than 5.0%, it is not sufficient to prevent the fine adhesive layer from being deteriorated by ultraviolet rays transmitted through the polyester film. Then, the trace of the adhesive layer remains and becomes a problem.

  Examples of ultraviolet absorbers include benzophenone compounds, 1,3,5-triazine compounds, benzoxazinone compounds, and the like, which can be used alone or in combination of two or more. In consideration of this, a benzoxazinone-based compound that is difficult to be yellowed is preferably used.

  An example of a benzoxazine-based compound used as an ultraviolet absorber is 2,2- (1,4-phenylene) bis [4H-3,1-benzoxazin-4-one].

  In the present invention, the coating layer may be provided by various known coating methods. However, it is desirable to provide the coating layer by a so-called in-line coating in which a coating layer is formed during film formation, particularly by a coating stretching method in which stretching is performed after coating.

  In-line coating is a method of coating within the process of manufacturing a polyester film. Specifically, it is a method of coating at any stage from melt extrusion of polyester to biaxial stretching and then heat setting and winding. is there. Normally, it is coated on either a substantially amorphous unstretched sheet obtained by melting and quenching, then a uniaxially stretched film stretched in the longitudinal direction (longitudinal direction), or a biaxially stretched film before heat setting. To do. In particular, as a coating stretching method, a method of stretching in the transverse direction after coating on a uniaxially stretched film is excellent.

  According to such a method, since film formation and coating layer coating can be performed simultaneously, there is an advantage in manufacturing cost, and since the film is stretched after coating, it becomes a uniform coating with a thin film, so that the adhesive performance is stable. To do. Moreover, the polyester film before biaxially stretching is first covered with an easy-adhesive resin layer, and then the film and the coating layer are stretched simultaneously, whereby the base film and the coating layer are firmly adhered.

  In addition, biaxial stretching of the polyester film is achieved by stretching the film in the lateral direction while holding the film edge with a tenter, so that the film is constrained in the longitudinal / lateral direction. High temperature can be applied while maintaining Therefore, since the heat treatment performed after coating can be performed at a high temperature that cannot be achieved by other methods, the film forming property of the coating layer is improved, and the coating layer and the polyester film are firmly adhered. As an easily-adhesive polyester film, the uniformity of the coating layer, the improvement of the film-forming property, and the adhesion between the coating layer and the film often produce favorable characteristics.

  In this case, the coating solution to be used is preferably an aqueous solution or an aqueous dispersion for safety reasons in terms of handling, working environment, and may contain an organic solvent if water is the main medium.

Next, the coating layer provided on the film in the present invention will be described.
The coating layer of the present invention is a coating layer containing a coating solution containing an acrylic resin having a hydrophilic group derived from a reactive emulsifier in the molecule, an oxazoline compound, and a compound having a quaternary ammonium group. It can be obtained by drying and curing. The coating solution may contain other components.

  When each component is not completely reacted, the resulting coating layer contains both unreacted products and reaction products of each component, and the ratio of the reaction product and unreacted product depends on the curing conditions. It can be changed as appropriate.

  As described above, in the conventional technique, adhesion and antistatic performance are not compatible at a sufficient level. The reason for this is not always clear, but it is thought that there are the following reasons.

  That is, in order to obtain sufficient antistatic performance by coating, it is necessary to increase the thickness of the coating layer in order to obtain the necessary amount of antistatic component. When the forced peeling test is performed after the top coat is processed, the coating layer itself tends to cohesive failure in addition to peeling at the interface between the coating layer and the top coat layer. Therefore, sufficient adhesion cannot be ensured. In order to prevent this cohesive failure, if the cohesive force of the coating layer itself is increased by using, for example, a crosslinking agent, the antistatic component network in the coating layer is inhibited, and the antistatic performance is reduced, or the coating layer is coated to prevent cohesive failure. When the layer is thinned, the total amount of antistatic components is reduced, and the antistatic performance is lowered. In addition, when the ratio of the antistatic component to the effective component of the entire coating layer is increased instead of increasing the thickness of the coating layer, if these components have poor adhesion, the resulting coating layer also has high adhesion. I couldn't.

  In other words, in order to achieve both antistatic performance and adhesion, it was necessary to find a new combination in the selection of materials to be used and the configuration of the coating layer.

  In the present invention, the acrylic resin contained in the coating solution for forming the coating layer is composed of a polymerizable monomer having a carbon-carbon double bond, as typified by acrylic and methacrylic monomers. It is a polymer.

  Examples of the polymerizable monomer having a carbon-carbon double bond include various carboxyl group-containing monomers such as acrylic acid, methacrylic acid, crotonic acid, itaconic acid, fumaric acid, maleic acid, citraconic acid, and the like. Various hydroxyl group-containing monomers such as salts, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, monobutylhydroxyfumarate, monobutylhydroxyitaconate , Various (meth) acrylic esters such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, lauryl (meth) acrylate, (meth) acrylimide, di Acetone acrylamide Various nitrogen-containing vinyl monomers such as N-methylolacrylamide or (meth) acrylonitrile, various styrene derivatives such as styrene, α-methylstyrene, divinylbenzene, vinyltoluene, vinyl acetate, vinyl propionate, etc. Various vinyl esters are exemplified, and in the present invention, a copolymer containing at least one of acrylic acid, methacrylic acid, acrylic acid ester, and methacrylic acid ester is particularly preferable.

  Moreover, when polymerizing such monomers to obtain an acrylic resin, the present invention is preferably obtained in the form of an aqueous dispersion using an emulsion polymerization method in which the monomers are dispersed and polymerized in water. An emulsifier is used to disperse the monomer in water. In the present invention, it is preferable to use a nonionic or anionic reactive emulsifier. In acrylic resins obtained using other emulsifiers, the resulting coating layer often does not exhibit sufficient adhesion. The reactive emulsifier here refers to an emulsifier having a radical polymerizable double bond in the molecule and copolymerizing in the resin during the polymerization of the acrylic resin. It is particularly preferable that it is nonionic, and in that case, a hydrophilic group using an alkylene oxide is preferable. In the case of an anionic property, a sulfate group is preferable as the hydrophilic group.

  The obtained acrylic resin aqueous dispersion preferably has an average dispersed particle size in the range of 0.01 to 0.2 μm, more preferably 0.02 to 0.09 μm. When the average dispersed particle size is larger than the above range, the appearance and adhesion of the resulting coating layer tend to be inferior. Moreover, when smaller than the said range, there exists a tendency which is still inferior to adhesiveness.

  In the present invention, the compound having a quaternary ammonium group contained in a coating solution for forming a coating layer refers to a compound having a quaternized ammonium group in the molecule, and particularly a polymer compound. Is preferred. Moreover, it is preferable that it is a water-soluble compound.

  In the present invention, for example, a polymer containing as a component a monomer having a quaternary ammonium group and an unsaturated double bond can be used.

  Specific examples of such a polymer include a polymer having a constituent represented by the following formula 1 or 2 as a repeating unit. These homopolymers and copolymers, and other plural components may be copolymerized.

In the above formula, R ¹ is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, R ² is —O— or —NH—, R ³ is an alkylene group having 1 to 6 carbon atoms or the structure of formula 1 Other possible structures, R ¹ , R ² and R ³ are each a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and X ⁻ is a monovalent anion.

In the above formula, R ¹ and R ² are each a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and X ⁻ is a monovalent anion.

The polymer having the component represented by the above formula 1 is excellent in transparency of the resulting coating layer and is preferable. However, in the coating stretching method, heat resistance may be inferior, and when used in the coating stretching method, X ⁻ is preferably not a halogen.

  The compound represented by the above formula 2 and other compounds having a quaternary ammonium base in the polymer skeleton are excellent in heat resistance, and antistatic properties are easily obtained even in the coating stretching method.

  Moreover, in this invention, it is necessary to contain an oxazoline compound in the coating liquid for forming a coating layer.

  The oxazoline compound in the present invention refers to a compound having an oxazoline group in the molecule, and can be synthesized using a monomer containing an oxazoline group as at least one raw material monomer. Examples of such monomers include 2-vinyl-2-oxazoline, 5-methyl-2-vinyl-2-oxazoline, 4,4-dimethyl-2-vinyl-2-oxazoline, 4,4-dimethyl-2- Vinyl-5,6-dihydro-4H-1, -oxazine, 4,4,6-trimethyl-2-vinyl-5,6-dihydro-4H-1,3-oxazine, 2-isopropenyl-2-oxazoline, 4,4-dimethyl-2-isopropenyl-2-oxazoline, 4-acryloyl-oxymethyl-2,4-dimethyl-2-oxazoline, 4-methacryloyl-oxymethyl-2,4-dimethyl-2-oxazoline, 4 -Methacryloyl-oxymethyl-2-phenyl-4-methyl-2-oxazoline, 2- (4-vinylphenyl) -4,4-dimethyl-2-o Oxazoline, 4-ethyl-4-hydroxymethyl-2-isopropenyl-2-oxazoline can be exemplified 4-ethyl-4-ethoxymethyl-2-isopropenyl-2-oxazoline and the like. One or more of these or other oxazoline group-containing monomers can be used.

  Moreover, in this invention, it is preferable to copolymerize the other component which does not contain an oxazoline group. Here, the other component is not particularly limited as long as it is a monomer that can be copolymerized with an oxazoline group-containing monomer. For example, a resin copolymerized with a vinyl oxazoline monomer using a monomer containing a vinyl group, such as (meth) acrylic acid esters, (meth) acrylamides, and styrene monomers, has high reactivity and is industrially obtained. Cheap.

  The coating solution may contain other cross-linking agents.

  The coating solution for providing the coating layer can contain components other than those described above as necessary. For example, surfactants, other binders and antistatic agents, lubricants, particles, antifoaming agents, coatability improving agents, thickeners, antioxidants, ultraviolet absorbers, foaming agents, dyes, pigments and the like. These additives may be used alone or in combination of two or more as necessary.

  The upper limit of the thickness of the coating layer as the film thickness on the finally obtained film is 0.07 μm, preferably 0.05 μm or less. The lower limit is 0.01 μm, preferably 0.02 μm or more. When the composition of the coating layer is limited as described above and the thickness of the coating layer is within the above range, both adhesion and antistatic performance can be achieved at a high level.

The antistatic property of the coating layer is measured by the surface specific resistance of the coating layer. It can be said that the lower the surface resistivity, the better the antistatic property. If the surface resistivity is 1 × 10 ¹³ Ω or less, it can be said that there is no problem with antistatic properties, and if it is 1 × 10 ¹² Ω or less, it can be said that the antistatic properties are extremely good.

  In the present invention, in order to prevent blocking, it is preferable to contain 3% by weight or more of the entire coating layer. When the content is less than this ratio, the effect of preventing blocking tends to be insufficient. If the content is too large, the blocking prevention effect is high, but the transparency of the coating layer may be reduced, the continuity of the coating layer may be impaired, and the coating strength may be reduced. May decrease. Specifically, it is preferably 15% by weight or less, more preferably 10% by weight or less. By this method, it becomes possible to achieve both easy adhesion performance and anti-blocking performance.

  As the particles, for example, inorganic particles such as silica, alumina, and metal oxide, or organic particles such as crosslinked polymer particles can be used. In particular, silica particles are preferred from the viewpoint of dispersibility in the coating layer and transparency of the resulting coating film.

  If the particle size is too small, the effect of preventing blocking is difficult to obtain, and if the particle size is too large, dropping from the coating film tends to occur. The average particle size is preferably about 1/2 to 10 times the thickness of the coating layer. Furthermore, if the particle size is too large, the transparency of the coating layer may be inferior, so the average particle size is preferably 300 nm or less, and more preferably 150 nm or less. The average particle diameter of the particles described here can be obtained by measuring the 50% average diameter of the number average of the particle dispersion with Microtrac UPA (Nikkiso Co., Ltd.).

  In the present invention, the coating liquid for providing the easy-adhesive coating layer may contain components other than those described above as necessary. For example, surfactants, other binders, antifoaming agents, coatability improvers, thickeners, antioxidants, ultraviolet absorbers, foaming agents, dyes, pigments and the like. These additives may be used alone or in combination of two or more as necessary.

  In the present invention, as a method for providing a coating layer on a polyester film, for example, a coating technique as shown in “Coating system” published by Yuji Harasaki, Tsuji Shoten, published in 1979 can be used. Specifically, air doctor coater, blade coater, rod coater, knife coater, squeeze coater, impregnation coater, reverse roll coater, transfer roll coater, gravure coater, kiss roll coater, cast coater, spray coater, curtain coater, calendar coater And techniques such as an extrusion coater and a bar coater.

  In addition, in order to improve the applicability | paintability to the film of a coating agent and adhesiveness, you may give a chemical process, a corona discharge process, a plasma process, etc. to a film before application | coating.

  The present invention will be described in more detail with reference to the following examples. However, the present invention is not limited to the following examples unless it exceeds the gist. In addition, the evaluation method in an Example and a comparative example is as follows.

(1) Measurement of intrinsic viscosity of polyester 1 g of polyester from which other polymer components and pigments incompatible with polyester have been removed are precisely weighed, and 100 ml of a mixed solvent of phenol / tetrachloroethane = 50/50 (weight ratio) is added. It was dissolved and measured at 30 ° C.

(2) Average particle size of particles added to the polyester film (d50)
The size of the particles was measured by a sedimentation method based on Stokes' resistance law using a Shimadzu centrifugal sedimentation type particle size distribution analyzer SA-CP3 type.

(3) Average particle diameter of coating composition The aqueous dispersion of the coating composition was diluted to an appropriate concentration, and the 50% average diameter of the number average was measured with a Nikkiso Microtrac UPA.

(4) Thickness of coating layer A film was fixed with an embedding resin, a cross section was cut with a microtome, and a sample was prepared by staining with 2% osmic acid at 60 ° C. for 2 hours. The obtained sample was observed with a transmission electron microscope (JEM2010 manufactured by JEOL Ltd.), and the thickness of the coating layer was measured. A total of 15 points on the film are measured, and an average of 9 points excluding 3 points from the larger value and 3 points from the smaller value is defined as the coating layer thickness.

(5) Internal haze The internal haze of the sample film was measured with a haze meter “HM-150” manufactured by Murakami Color Research Laboratory in accordance with JIS-K-7136. In addition, it measured in the quartz cell by using ethanol as a rough surface compensation solvent.

(6) Light transmittance at 380 nm With a spectrophotometer UV3100 manufactured by Shimadzu Corporation, the light transmittance is measured continuously at a low scanning speed, a sampling pitch of 2 nm, and a wavelength range of 300 to 700 nm. Was detected.

(7) Surface resistivity Using a high resistance measuring instrument made by Hewlett-Packard Japan: HP4339B and measurement electrode: HP16008B, measuring the surface resistivity after conditioning the sample for 30 minutes in a measurement atmosphere at 23 ° C. and 50% RH did.

(8) Adhesiveness The active energy ray-curable resin composition as shown below was applied on the coating layer of the sample so that the thickness after curing was 7 μm, and was applied to a hot air drying oven set at 80 ° C. And dried for 1 minute. Next, using a high-pressure mercury lamp with an energy of 120 W / cm, curing was performed by irradiation for about 7 seconds at an irradiation distance of 100 mm to obtain a laminated film in which an active energy ray-curable resin layer was provided on the film. The integrated light amount of the active energy ray at this time was measured using an ultraviolet integrated light amount meter UIT-250 and a light receiver UVD-C365 (manufactured by USHIO INC.), And was about 110 mJ / cm ² . The active energy ray-cured resin layer of the obtained laminated film is cross-cut so that there are 100 grids per inch, and 18 mm wide tape (Nichiban cello tape (registered trademark) CT-18) Was attached, a rapid peel test was performed, and the adhesion was evaluated based on the peeled area. The judgment criteria are as follows.
A: Number of cross-cuts = 0
○: 1 ≦ Number of cross cuts ≦ 10
Δ: 11 ≦ number of cross-cuts ≦ 20
×: 21 <Number of cross-cuts peeled ××: Whole surface peeled Cured resin composition: 80 parts by weight of KAYARAD DPHA manufactured by Nippon Kayaku, 20 parts by weight of KAYAARD R-128H manufactured by Nippon Kayaku, 5 IRGACURE651 manufactured by Ciba Specialty Chemical A composition in which a mixture by weight is diluted with toluene to a concentration of 30% by weight.

(9) Light resistance test of adhesive layer After setting the sample so that UV light hits the opposite side of the film surface provided with the fine adhesive layer, the sample was irradiated with a xenon lamp for 200 hours, and then the edge portion of the sample was rubbed with fingers. The degree of layer peeling was evaluated according to the following criteria. The evaluation results were as shown in Table 2.
○: No peeling at all ×: Partial peeling

(10) Overall evaluation as a decorative film ○: Adhesiveness, antistatic property, light resistance of the adhesive layer are all good,
Suitable for decoration film ×: Adhesiveness, antistatic property, light resistance of adhesive layer is inferior, and unsuitable for protective film

The polyester raw materials used in Examples and Comparative Examples are as follows.
(Polyester 1): Polyethylene terephthalate having an intrinsic viscosity of 0.66 substantially containing no particles (Polyester 2): containing 0.3 parts by weight of amorphous silica having an average particle diameter of 1.6 μm Polyethylene terephthalate No. 66 (Polyester 3): (Polyester 1) was subjected to a twin screw extruder with a vent, and 2,2- (1,4-phenylene) bis [4H-3,1-benzoxazine- 4-one] (CYTECOR UV-3638, molecular weight 369, benzoxazine-based CYTEC Co., Ltd.) was supplied at a concentration of 10% by weight, and the intrinsic viscosity was 0.59 polyethylene terephthalate.

Moreover, the following was used as a coating composition.
(E1): a polymer compound having a number average molecular weight of 20000, obtained by copolymerizing a structural unit of the following formula 1-1 and a structural unit of the following formula 1-2 at a weight ratio of 95/5.

(E2): a polymer compound composed of a structural unit of the following formula 2-1

(E3): a polymer compound having a structure in which a structural unit of the following formula 3-1 and an acrylate ester are copolymerized

(A1): In the presence of alkoxy polyethylene glycol methacrylate as a reactive emulsifier, copolymerized mainly with acrylic acid alkyl ester, methacrylic acid alkyl ester, methacrylic acid, N-methylolacrylamide, glass transition point is 50 ° C., acid Acrylic resin (C1) having a valence of 14 mgKOH and an average particle size of 0.05 μm: Epocross WS-500 (manufactured by Nippon Shokubai Co., Ltd.), a polymer type crosslinking agent in which an oxazoline group is branched to an acrylic resin
(C2): Becamine J-101 (made by Nippon Materials), which is methoxymethylol melamine.
(C3): Denacol EX-521 (manufactured by Nagase ChemteX) which is polyglycerol polyglycidyl ether
(F1): Silica sol aqueous dispersion having an average particle size of 0.07 μm (S1): Surfactant Surfinol 465 (manufactured by Air Products)

Comparative Example 1:
A mixed raw material in which the polyester 1 and the polyester 2 are mixed at a ratio of 88% and 12%, respectively, is used as a raw material for the A layer, and a mixed raw material in which the polyester 1 and the polyester 3 are mixed at a ratio of 95% and 5%, respectively. As raw materials, each was supplied to two extruders, melted at 285 ° C., and then on the casting drum cooled to 40 ° C. with the A layer as the outermost layer (surface layer) and the B layer as the intermediate layer. Three layers (ABA) were coextruded and cooled and solidified so that the thickness composition ratio was A: B: A = 3: 94: 3 to obtain a non-oriented sheet. Next, the film was stretched 3.4 times in the longitudinal direction at a film temperature of 85 ° C. using the roll peripheral speed difference, then led to a tenter, stretched 4.0 times at 120 ° C. in the transverse direction, and heat-treated at 230 ° C. Thereafter, the film was rolled up on a roll to obtain a laminated polyester film having a thickness of 100 μm and having a coating layer on both sides. The properties of the obtained film are shown in Table 2 below.

Examples 1-5, Comparative Examples 2-6:
Examples 1 to 5 and Comparative Example were applied in the same manner as in Comparative Example 1 except that the coating liquids P1 to P9 shown in Table 1 below were applied to both sides of the longitudinally stretched film, led to a tenter, and laterally stretched. 1 to 6 laminated polyester films were obtained. The properties of the obtained film are shown in Table 2 below.

Comparative Example 7:
A laminated polyester film was obtained in the same manner as in Example 1 except that the raw material of layer B was 100% of the above polyester 1. The properties of the obtained film are shown in Table 2 below.

  Next, on one side of this film, 100 parts of silicone coating liquid (linear polyorganosilicone having a vinyl group only at the terminal group (“X-62-1347” manufactured by Shin-Etsu Chemical Co., Ltd.)) as a fine adhesion layer (solid weight) 2 parts) of platinum catalyst (“CAT-PL-56” manufactured by Shin-Etsu Chemical Co., Ltd.) using a bar coater, and drying and curing the coating film at 150 ° C. for 2 minutes. A thin adhesive layer having a thickness of 25 μm was provided, and the film thus obtained has excellent properties as shown in Table 2. Therefore, the film was actually attached to a display screen of a mobile phone as a protective film. The visibility when used was good except for Comparative Example 7 and could be used preferably.

  The film of the present invention can be suitably used as a laminated polyester film for decoration in outdoor applications that require excellent anti-UV properties and easy anti-adhesiveness and easy adhesion.

Claims (2)

A laminated polyester film having a coating layer on at least one surface of a polyester film, the coating layer having a hydrophilic group derived from a reactive emulsifier in the molecule, an oxazoline compound, and a compound having a quaternary ammonium group A laminated polyester film, wherein the laminated polyester film has a light transmittance of 380 nm of 5% or less. A polyester film for decorative film comprising a slightly adhesive layer on at least one surface of the laminated polyester film according to claim 1.