JP2006264135A - Polyester film for transfer foil - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyester film for transfer foil which is excellent in glossiness of a molding surface after transfer and suitable for applications including in-mold molding. <P>SOLUTION: As regards the polyester film for the transfer foil, in the surface at least on the transfer surface side, the value of average central surface roughness SRa is 15 nm or below, and the number of projections of at least 200 nm is 1% or above of the total number of projections. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a polyester film for transfer foil. More specifically, the present invention relates to a polyester film for transfer foil that is excellent in gloss on the surface of a molded product after transfer and suitable for in-mold molding applications.

  Biaxially oriented polyester film represented by polyethylene terephthalate (PET) film is used in a wide range of fields such as industrial materials, magnetic recording materials and packaging materials because of its excellent mechanical strength, thermal properties, humidity properties and many other excellent properties. in use.

  Generally, a transfer foil is formed by sequentially laminating an easy-adhesion layer, a release layer, a printing layer, an adhesive layer, and the like on one side of a polyester film as a base material. As a transfer method of these transfer foils, a transfer device is used to transfer to a transfer object with a heating roll, or a so-called hot stamping method, or an adhesive layer is in contact with a mold resin of an injection molding machine or a blow molding machine. After setting the transfer material, injection molding or blowing of molding resin, transfer at the same time as molding, take out the molded product from the mold after cooling, generally known as so-called molding simultaneous transfer method represented by in-mold molding, etc. It has been. Such a transfer method is used in plastic molded products used for household appliances, automobile interior parts, kitchenware, cosmetic containers, toys and stationery.

  On the other hand, in recent years, various demands regarding easy moldability and design properties for plastic molded products have increased, for example, excellent flexibility and excellent conformability to the surface shape of the transferred material and deep drawing workability. Transfer foils (see Patent Document 1) and those obtained by copolymerizing or blending PET and polybutylene terephthalate (PBT) to improve workability (see Patent Document 2 and Patent Document 3) have been proposed.

However, recently, there has been a demand for more advanced improvements to improve production efficiency and achieve higher designability. For example, if the transfer foil is charged with static electricity in the transfer process, whiskering or dust may be caused in the printing process, causing trouble. For example, in the case of metal substitutes, high glossiness is required on the surface of the molded product after transfer.
JP-A-6-210799 Japanese Patent Laid-Open No. 10-17683 JP 2001-354843 A

  In view of such a situation, the present invention aims to provide a polyester film for transfer foil that improves such drawbacks and is excellent in gloss of the surface of a molded product after transfer, and suitable for in-mold molding applications. To do.

  In order to achieve this object, the laminated polyester film for transfer foil of the present invention has the following constitution. That is, the polyester film for transfer foil of the present invention has a center plane average roughness (SRa) value of 15 nm or less at least on the transfer surface side surface, and the number of protrusions of 200 nm or more is 1% or more of the total number of protrusions. It is a polyester film for transfer foil characterized by these.

And the polyester film for transfer foil of this invention has the following preferable aspect.
(A) The number of projections of 200 nm to 800 nm is 3% to 20% of the total number of projections on at least the transfer surface side surface.
(B) The root mean square roughness (RMS) value is 20 nm or less at least on the surface on the transfer surface side.
(C) An antistatic layer is provided on the opposite surface of the transfer surface.
(D) The antistatic layer is a coating layer formed of a component that can be applied with an aqueous coating liquid and stretched in at least one direction.
(E) The antistatic layer contains polythiophene and / or a polythiophene derivative, and the surface specific resistance of the surface of the antistatic layer is 1 × 10 ¹⁰ Ω / □ or less.
(F) An easy-adhesion layer is provided on the transfer surface side.
(G) The easy-adhesion layer is a coating layer formed of a component that can be applied with an aqueous coating liquid and stretched in at least one direction.
(H) The easy adhesion layer contains a polyester resin.
(I) A titanium compound is used as a polymerization catalyst for the polyester constituting the polyester film.
(J) The polyester film is a simultaneous biaxially stretched film.

  According to the present invention, it is possible to produce a polyester film for transfer foil suitable for in-mold molding applications and the like, which is excellent in glossiness of the surface of a molded product after transfer, antistatic property during processing and easy adhesion. .

  Hereinafter, the polyester film for transfer foil of the present invention will be described in more detail. The polyester film which is the base material of the polyester film for transfer foil of the present invention is basically composed of polyester.

  The polyester used in the present invention is a polymer compound having an ester bond as the main bond chain of the main chain, and can be obtained by polycondensation of dicarboxylic acid and diol. Examples of the dicarboxylic acid component include terephthalic acid, isophthalic acid, diphenylcarboxylic acid, diphenylsulfone dicarboxylic acid, diphenoxyethanedicarboxylic acid, 5-sodium sulfoisophthalic acid, phthalic acid and other aromatic dicarboxylic acids, oxalic acid, and succinic acid. , Eicoic acid, adipic acid, sebacic acid, dimer acid, dodecanedioic acid, maleic acid, fumaric acid and other aliphatic dicarboxylic acids, cyclohexanedicarboxylic acid and other alicyclic dicarboxylic acids, trimellitic acid, and pyromellitic acid, etc. A polyfunctional acid etc. can be mentioned. On the other hand, examples of the diol component include aliphatic glycols such as ethylene glycol, propanediol, butanediol, pentanediol, hexanediol, neopentyl glycol and triethylene glycol, aromatic glycols such as bisphenol A and bisphenol S, diethylene glycol, And polytetramethylene glycol.

  In the polyester, there are various additives such as antioxidants, heat stabilizers, weathering stabilizers, UV absorbers, organic lubricants, organic and inorganic particles, pigments, dyes, fillers, antistatic agents and nuclei. An agent or the like may be added as long as the effects of the present invention are not impaired.

  Further, when a titanium-based catalyst is used as a polyester polymerization catalyst, aggregates are reduced, which is a more preferable mode. Examples of the titanium-based polymerization catalyst include titanium alkoxides such as titanium tetrabutoxide and titanium tetraisopropoxide, composite oxides and titanium complexes whose main metal elements are titanium and silicon, and the obtained polyester. It is preferable to use 0.0005 to 0.15% by weight in terms of titanium atoms. The polyester thus obtained contains a titanium-based catalyst, and in some cases, the polymerization catalyst function may be deactivated.

  The polyester film used as a substrate in the present invention may be either a single layer or a multilayer structure, but if it is a multilayer structure, different polyester formulations can be taken for the inner layer and the outer layer, and this is a preferred mode for film surface design. is there.

  The total thickness of the polyester film for transfer foil of the present invention is not particularly limited because it is appropriately selected depending on the use for which the polyester film for transfer foil of the present invention is used, but mechanical strength, handling properties, productivity, etc. From the viewpoint, it is preferably 12 to 188 μm, and most preferably 30 to 100 μm.

  In the present invention, at least on the surface on the transfer surface side, the value of the center plane average roughness (SRa) is required to be 15 nm or less in order to achieve the object of the present invention. This center plane average roughness (SRa) Is preferably 12 nm or less, more preferably 9 nm or less, and most preferably 6 nm or less. In other words, by making the transfer surface side surface highly smooth, the release layer, protective layer, and print layer that are sequentially laminated on the transfer surface side also become highly smooth, so that the surface of the transferred object after transfer also becomes highly smooth. As a result, the glossiness of the surface of the molded article is increased. When the value of the center plane average roughness (SRa) of the transfer surface side surface exceeds 15 nm, the desired glossiness cannot be obtained. Further, the lower limit of the value of SRa is not particularly limited, but is preferably 1 nm or more from the viewpoint of film formation stability, slit property after film formation, film transportability during processing, and the like.

  At the same time, in the present invention, the root mean square roughness (RMS) value is preferably 20 nm or less, the root mean square roughness (RMS) value is more preferably 15 nm or less, and most preferably 10 nm. It is as follows. Since the root mean square roughness (RMS) value is the square root of the mean value of the sum of squares, the larger the number of larger protrusions, the larger the value. Therefore, it is a value that serves as a guide for a large number of protrusions. An excessively large protrusion not only greatly affects the smoothness but can also cause surface scratches, so the design of the number of protrusions is an important issue. When the value of the root mean square roughness RMS exceeds 20 nm, the glossiness is lowered, which is not preferable. Further, the lower limit of the RMS value is not particularly limited, but is preferably 1 nm or more from the viewpoint of slit property after film formation and film transportability during processing.

  Furthermore, in the present invention, the number of protrusions of 200 nm or more is required to be 1% or more of the total number of protrusions, and preferably 3% or more, at least for the protrusion distribution on the transfer surface side surface. The number of projections of 200 nm to 800 nm is preferably 3% to 20% of the total number of projections, and most preferably 5% to 15%. The presence of projections of 200 nm or more is important from the viewpoint of improving the winding property at the time of slitting and the blocking resistance. If the protrusion is less than 200 nm, the effect of the above characteristics is weak, and if the protrusion exceeds 800 nm, the smoothness is affected. When the ratio of protrusions of 200 nm or more is less than 1%, the effect of the above characteristics is thin, and when it exceeds 20%, the smoothness is affected.

  The method for achieving the above surface condition is not particularly limited, but organic or / and inorganic particles having a specific particle size / size distribution are contained in the base polyester film or in the coat layer on the base polyester film. The method of making it contain etc. are mentioned.

  Examples of the organic particles include crosslinked polystyrene, crosslinked acrylic resin, melamine resin, and benzoguanamine resin. As the inorganic particles, for example, silica, colloidal silica, beaded silica, alumina, alumina sol, kaolin, talc, mica, clay, calcium carbonate, metal oxide (such as tin oxide) and the like are preferably used. These organic particles and inorganic particles are preferably spherical monodisperse particles. Moreover, as a particle | grain size, it is preferable that an average particle diameter is 0.001-6 micrometers, More preferably, it is 0.01-3 micrometers, Most preferably, it is 0.05-1.5 micrometers. In order to prevent the particles from falling off, the particles are preferably contained in the base polyester film.

  Although it does not specifically limit as content of this particle | grain, 0.0001-50 weight% with respect to the sum total of resin which forms each layer can be mentioned as a preferable range.

  Moreover, it is preferable to employ a composite film configuration (multilayer configuration) as the base polyester film, and to design the thickness of the outer layer according to the average particle diameter of the particles added to the outer layer. This is because by bringing the thickness of the outer layer close to the average particle diameter, irregularities due to surface waviness can be removed, and a smoother surface can be designed. In addition, by using particles having an average particle size of 0.5 μm or less and particles of 0.5 μm or more and 1.5 μm or less in combination, moderately high protrusions for removing air between layers when the film is wound in a roll shape While possessing, it is possible to express slipperiness with a small protrusion and to keep the center plane average roughness (SRa) and root mean square roughness (RMS) small.

  The polyester film for transfer foil of the present invention preferably has an antistatic layer on the non-transfer surface (the surface opposite to the transfer surface). By having the antistatic layer, it is possible to suppress the generation of static electricity, so there is an effect of reducing troubles due to dust adhesion and the generation of whiskers during processing, and a dramatic improvement in yield can be expected.

  Methods for applying the antistatic layer include a method of kneading into an outer layer as a multilayer structure and a method of coating offline after film formation, but the antistatic layer is used to prevent environmental contamination and explosion-proof properties during film production. From the viewpoint of production cost, the coating layer is preferably formed by being stretched in at least one direction after the application of the aqueous coating liquid, and is preferably formed within the production process for biaxially orienting the polyester film. . Although the timing of the stretching is not particularly limited, a method of biaxial stretching after applying the aqueous coating liquid, or a method of applying the aqueous coating liquid after longitudinal (longitudinal direction of the film) and further laterally stretching is preferably used. As a coating method of the aqueous coating liquid, various coating methods such as reverse coating method, gravure coating method, rod coating method, bar coating method, die coating method and spray coating method can be preferably used. It is not limited.

  The thickness of the antistatic layer in the present invention is usually preferably 10 to 1000 nm, more preferably 15 to 200 nm, and most preferably 30 to 100 nm. When the thickness of the antistatic layer is too thin, the antistatic function becomes poor. On the other hand, when the antistatic layer is too thick, the appearance is inferior, the antistatic layer falls off during the transfer material manufacturing process and the transfer process, and the transfer foil film manufacturing cost increases.

  In the antistatic layer of the present invention, for example, polyester resin, polyurethane resin, antioxidant, heat stabilizer, weather stabilizer, ultraviolet absorber, organic Lubricants, pigments, dyes, organic or inorganic fine particles, fillers, antistatic agents, and nucleating agents may be blended. The lubricant and fine particles have the effect of improving the slipperiness of the film and facilitating handling. The average particle size of the lubricant and fine particles is preferably 50% to 500% of the thickness of the antistatic layer. If the average particle size is less than 50%, the slippery effect is insufficient, and if it exceeds 500%, the slippery agent and fine particles are likely to fall off. Moreover, the polyester resin mix | blended is anticipated the effect which improves adhesiveness with a base-material polyester film.

The surface specific resistance of the surface of the antistatic layer is preferably 1 × 10 ¹⁰ Ω / □ or less, more preferably 1 × 10 ⁸ Ω / □ or less, and most preferably 1 × 10 ⁶ Ω / □ or less. . When the surface specific resistance exceeds 1 × 10 ¹⁰ Ω / □, the antistatic performance is inferior and it is difficult to improve troubles in the processing process. The lower limit value of the surface specific resistance is not particularly limited, but is preferably 1 × 10 ² Ω / □ or more from the viewpoint of production cost and film formation stability.

  Examples of the antistatic agent used in the antistatic layer satisfying such characteristics include a compound having a quaternary ammonium base that is a cationic conductor, a polyaniline-based conductive agent that is a conjugated electronic conductor, and a tin oxide-based conductive material. And a polythiophene-based conductive agent. An anionic conductor having a sulfonic acid group or the like that is widely used in general is not preferable because the antistatic performance changes greatly due to humidity and the water resistance is poor. When a compound having a quaternary ammonium base which is a cationic conductor is used, it can be used because the change in antistatic performance due to humidity is relatively small and the water resistance is relatively strong. On the other hand, when polyaniline conductive agent, tin oxide conductive agent and polythiophene conductive agent, which are conjugated electron conductors, are used, the electronic conduction mechanism does not depend on moisture in the air, so the change in antistatic performance due to humidity The amount is very small and suitable. In particular, when polythiophene and a polythiophene derivative are used, it is a particularly preferable embodiment because it is excellent in transparency of the coating film, adhesion to the base polyester film, and coating appearance.

  The compound having a quaternary ammonium base that is a cationic conductor is a compound having a component containing a quaternary ammonium base in the main chain or side chain of the molecular chain. Examples thereof include a pyrrolidinium ring, a quaternary compound of alkylamine, a copolymer of these with acrylic acid or methacrylic acid, a quaternary compound of N-alkylaminoacrylamide, and a vinylbenzyltrimethylammonium salt. Examples of the anion serving as a counter ion for the quaternary ammonium base include halogen, alkyl sulfate, alkyl sulfonate, and nitric acid. The compound having a quaternary ammonium base is preferably a polymer compound. If the molecular weight is too low, the antistatic agent may be transferred from the surface of the antistatic layer to the reverse side, or to a roll or mold in the process, which may cause adhesion failure on the reverse side or a product defect. Sometimes. The number average molecular weight of the compound having a quaternary ammonium base is usually preferably 2000 or more, more preferably 5000 or more. Further, if the molecular weight is too large, there are problems that the viscosity of the coating solution becomes too high and the followability at the time of stretching is deteriorated. Therefore, the number average molecular weight is preferably 100,000 or less.

  Polythiophene and polythiophene derivatives that are conjugated electronic conductors can be obtained, for example, by polymerizing a compound represented by the following general formula (1) or the following general formula (2) in the presence of a polyanion. .

  In the general formula (1), R1 and R2 each independently represent a hydrogen element, an aliphatic hydrocarbon group having 1 to 12 carbon atoms, an alicyclic hydrocarbon group, or an aromatic hydrocarbon group, for example, Methyl group, ethyl group, propyl group, isopropyl group, butyl group, cyclohexylene group and phenyl group. Moreover, in said General formula (2), n is an integer of 1-4.

  In the polyester film for transfer foil of the present invention, it is preferable to use a polythiophene or a polythiophene derivative having the structural formula represented by the general formula (2). For example, in the general formula (2), n = 1 (methylene group) ), N = 2 (ethylene group) and n = 3 (propylene group). Among them, particularly preferable is an ethylene group compound of n = 2, that is, poly-3,4-ethylenedioxythiophene. Examples of polythiophene or polythiophene derivatives include compounds in which a functional group is bonded to positions 3 and 4 of the thiophene ring. As described above, a compound in which an oxygen atom is bonded to the 3rd and 4th carbon atoms is preferable. For a compound having a structure in which a carbon atom or a hydrogen atom is directly bonded to the carbon atom, it may not be easy to make the coating liquid aqueous.

  In the polyester film for transfer foil of the present invention, the antistatic treatment layer preferably contains a composition comprising the polythiophene and a polyanion or a composition comprising the polythiophene derivative and a polyanion compound.

  The polyanionic compound in the present invention is an acidic polymer in a free acid state, and high molecular carboxylic acid, high molecular sulfonic acid, polyvinyl sulfonic acid and the like are mentioned as preferable compounds. Examples of the high-molecular carboxylic acid include polyacrylic acid, polymethacrylic acid, and polymaleic acid. Examples of the polymer sulfonic acid include polystyrene sulfonic acid. Among these, polystyrene sulfonic acid is most preferable in terms of conductivity. It may take the form of a salt in which a part of the free acid is neutralized. By using these polyanions at the time of polymerization, it is considered that a polythiophene compound that is originally insoluble in water is easily dispersed in water or made water-based, and that the function as an acid also functions as a doping agent for the polythiophene compound. .

  In the present invention, the polymer carboxylic acid and polymer sulfonic acid can be used in the form of copolymerization with other copolymerizable monomers such as acrylic acid ester, methacrylic acid ester and styrene. The molecular weight of the polymer carboxylic acid or polymer sulfonic acid used as the polyanionic compound is not particularly limited, but the weight average molecular weight is preferably 1,000 to 1,000,000, more preferably from the viewpoint of the stability and conductivity of the coating agent. 5,000 to 150,000. In addition, alkaline salts such as lithium salts and sodium salts, ammonium salts, and the like may be partially included within the range not impairing the characteristics of the present invention. In the case of neutralized salts, polystyrene sulfonic acid and ammonium salts, which function as very strong acids, are known to shift to the acidic side due to the progress of the equilibrium reaction after neutralization. I think it works.

  In the present invention, the polyanionic compound is preferably present in excess of the solid content by weight ratio relative to the polythiophene or polythiophene derivative from the viewpoint of conductivity, and the polythiophene or polythiophene derivative is contained in an amount of polyanion with respect to 1 part by weight. The ionic compound is preferably 1 to 5 parts by weight, more preferably 1 to 3 parts by weight.

  The composition comprising the above polythiophene or polythiophene derivative and a polyanionic compound is, for example, disclosed in JP-A-6-295016, JP-A-7-292081, JP-A-1-313521, JP-A-2000-6324. Although it can be produced by the method described in the publication, European Patent EP 602731, and US Pat. No. 5,391,472, other methods may be used.

  For example, 3,4-ethylenedioxythiophene was obtained using an alkali metal salt of 3,4-dihydroxythiophene-2,5-dicarboxyester as a starting material, and potassium peroxodisulfate was added to a polystyrenesulfonic acid aqueous solution. And iron sulfate and 3,4-ethylenedioxythiophene obtained above are introduced and reacted, and polyanionic compound such as polystyrene sulfonic acid is added to polythiophene such as poly (3,4-ethylenedioxythiophene). The complexed composition is obtained.

  The antistatic treatment layer in the present invention preferably contains a composition comprising the above polythiophene or polythiophene derivative and a polyanionic compound and a crosslinking agent. As the crosslinking agent, for example, a melamine crosslinking agent, an epoxy crosslinking agent, an oxazoline crosslinking agent, an isocyanate crosslinking agent, and an acrylamide crosslinking agent can be used. The crosslinking agent is preferably a crosslinking agent having a molecular weight of 1000 or less, more preferably 800 or less, and still more preferably 600 or less. In particular, by using a water-soluble cross-linking agent having a molecular weight of 1000 or less, flexibility and fluidity in the stretching process are expressed, and the stretchable followability after drying of the mixture forming the laminated film is improved, and the coating film is cracked. The whitening phenomenon is suppressed and transparency is imparted. When the molecular weight is too large, the coating film is cracked during stretching after coating and drying, so that the transparency tends to decrease. The temperature at which the thermal loss rate of the epoxy-based crosslinking agent is 5% is preferably 230 ° C. or higher, more preferably 250 ° C. or higher, and particularly preferably 270 ° C. or higher. When the temperature at which the heat loss rate is 5% is less than 230 ° C., the epoxy component may be dispersed in the polyester film production process, particularly in the transverse stretching to heat treatment oven, thereby fouling the process.

  As the crosslinking agent, an epoxy-based crosslinking agent, particularly a water-soluble epoxy-based crosslinking agent is particularly preferable, and an antistatic layer excellent in transparency, antistatic property and coating film appearance can be formed. The type of the epoxy-based crosslinking agent is not particularly limited, and examples thereof include sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, diglycerol polyglycidyl ether, polyethylene glycol diglycidyl ether and polyethylene glycol diglycidyl ether. Can be used. For example, an epoxy compound “Denacol” (registered trademark) manufactured by Nagase Chemtech Co., Ltd. (EX-611, EX-614, EX-512, EX-521, EX-412, EX-313, EX-810, EX-830, EX-850, etc.), diepoxy / polyepoxy compounds (SR-EG, SR-8EG, SR-GLG, etc.) manufactured by Sakamoto Yakuhin Kogyo Co., Ltd., and epoxy crosslinking agent “EPICLON” (registered trademark) manufactured by Dainippon Ink Industries, Ltd. ) EM-85-75W or CR-5L can be used preferably.

  The mixing ratio of the solid content of the composition comprising the polythiophene or polythiophene derivative and the polyanion compound and the solid content of the cross-linking agent is as follows. When the sum of the amounts is 100 parts by weight, the solid content of the crosslinking agent is preferably 30 parts by weight to 90 parts by weight, and more preferably 50 parts by weight to 85 parts by weight. When the solid content of the crosslinking agent is more than 90 parts by weight, the antistatic property is hardly exhibited. On the other hand, when the solid content of the crosslinking agent is less than 30 parts by weight, cracks are likely to occur in the antistatic layer, resulting in inferior transparency and difficulty in developing antistatic properties.

  The polyester film for transfer foil of the present invention preferably has an easy adhesion layer on the transfer surface. In the transfer foil, the easy adhesion layer, the release layer, the printing layer, and the like are sequentially laminated in the process to express the function, but the easy adhesion layer is laminated in the film forming process of the base polyester film. Since the step of providing an easy-adhesion layer can be omitted, this is a preferred embodiment from the viewpoint of manufacturing cost and processing time.

  As a method for providing an easy-adhesion layer on the transfer surface, there are a method of kneading into an outer layer as a multilayer structure, a method of coating off-line after film formation, etc., but an easy-adhesion layer is used to prevent environmental contamination during film production. From the viewpoint of explosion-proof property, production cost, etc., it is preferably a coating layer formed by being stretched in at least one direction after applying an aqueous coating liquid, and is formed within a production process in which a base polyester film is biaxially oriented. More preferably. Although the timing of the stretching is not particularly limited, a method of biaxial stretching after applying the aqueous coating liquid, or a method of applying the aqueous coating liquid after longitudinal (longitudinal direction of the film) and further laterally stretching is preferably used. As a coating method of the aqueous coating liquid, various coating methods such as reverse coating method, gravure coating method, rod coating method, bar coating method, die coating method and spray coating method can be preferably used. It is not limited.

  10-2000 nm is preferable and, as for the thickness of an easily bonding layer, More preferably, it is 50-1000 nm. If the thickness of the easy-adhesion layer is too thin, adhesion to the release layer and solvent resistance may be insufficient, and if it is too thick, the slip resistance and blocking resistance when used as a film roll will deteriorate. There is a case.

  Moreover, it is preferable that an easily bonding layer contains a polyester resin. When a polyester resin is used for the easy-adhesion layer, interfacial peeling and scraping are less likely to occur because of its high affinity with the base polyester film, and the coating appearance is improved in the case of aqueous coating. Moreover, it is preferable that it is a polyester resin also from a viewpoint of manufacturing cost or the adhesive force with a mold release layer.

  In order to apply as an aqueous coating liquid, the polyester contained in the easy-adhesion layer is preferably a copolymerized polyester containing a compound containing a sulfonate group or a compound containing a carboxylate group as a copolymerization component. Examples of the compound containing a sulfonate group include sulfoterephthalic acid, 5-sulfoisophthalic acid, 4-sulfoisophthalic acid, 4-sulfonaphthalene-2,7-dicarboxylic acid, and alkali metal salts and alkaline earth metals thereof. Salts and ammonium salts can be used, but are not limited thereto. Examples of the compound containing a carboxylate group include trimellitic acid, trimellitic anhydride, pyromellitic acid, pyromellitic anhydride, 4-methylcyclohexene-1,2,3-tricarboxylic acid, trimesic acid, 1,2, 3,4-butanetetracarboxylic acid, 5- (2,5-dioxotetrahydrofurfuryl) -3-cyclohexene-1,2-dicarboxylic acid, cyclopentanetetracarboxylic acid, 2,3,6,7-naphthalenetetra Carboxylic acid, 1,2,5,6-naphthalene tetracarboxylic acid, ethylene glycol bistrimellitate, 2,2 ', 3,3'-diphenyltetracarboxylic acid, thiophene-2,3,4,5-tetracarboxylic acid , Ethylenetetracarboxylic acid, etc., or alkali metal salts thereof, alkaline earth metal salts and ammonia And the like can be used unsalted, but is not limited thereto.

  The polyester contained in the easy-adhesion layer is preferably a copolymerized polyester containing diethylene glycol as a copolymerization component. By making this component into a copolymerization component, the solvent resistance of the easy-adhesion layer especially with respect to alcohol can be improved, and the affinity with the base polyester film can be improved. As other copolymerization components, known dicarboxylic acids and diols can be used. Examples thereof include, but are not limited to, the dicarboxylic acids and diols described above. Moreover, the compound containing an above described sulfonate group and the compound containing a carboxylate group can also be included as a copolymerization component. The range of the preferable glass transition point of this copolyester is 0-60 degreeC, More preferably, it is 10-45 degreeC.

  The content of the copolymerized polyester containing diethylene glycol as a copolymerization component is preferably 10 to 60% by weight, more preferably 20 to 50% by weight, based on the total amount of resins forming the easy-adhesion layer. If the content is too small, the solvent resistance and the adhesive strength with the base polyester film may be inferior. If the content is too large, the blocking resistance may be inferior when used as a film roll.

  The resin other than the copolyester having a copolymer component of diethylene glycol that forms the easy-adhesion layer is not particularly limited as long as the effects of the present invention are not impaired, but other polyester resins, acrylic resins, A urethane resin, an epoxy resin, a silicone resin, a urea resin, a phenol resin, and the like can be exemplified. Among them, other polyester resins can be preferably exemplified.

  Further, in the easy-adhesion layer in the present invention, for example, an antioxidant, a heat stabilizer, a weather stabilizer, an ultraviolet absorber, an organic lubricant, a pigment, and a dye are within the range where the effects of the present invention are not impaired. Organic or inorganic fine particles, fillers, antistatic agents, nucleating agents, and the like may be blended.

  The polyester film constituting the polyester film for transfer foil of the present invention is preferably a biaxially oriented film. A biaxially oriented polyester film is produced by stretching a non-stretched polyester sheet or film in the longitudinal direction and the width direction in a so-called biaxial direction, and is a pattern of biaxial orientation by wide-angle X-ray diffraction. Is shown. The biaxial stretching method may be either a sequential biaxial stretching method or a simultaneous biaxial stretching method, but in the case of simultaneous biaxial stretching, the smooth film surface is not easily scratched, and the on-line coating is performed at a low speed. There are advantages such as being able to. The film structure may be a single layer, or a laminated structure composed of polyester compositions A, B, and C having different compositions, for example, a two-layer structure of A / B, A / B / A, or A / B A three-layer structure of / C may be used. In this case, the lamination thickness ratio may be arbitrarily set, but the outer layer is preferably designed in accordance with the particle diameter to be added in order to remove surface waviness and increase smoothness. These laminated structures can be manufactured as a laminated film by coextrusion. In particular, in the case of the A / B two-layer structure, a layer having few particles and a smooth surface and excellent gloss after transfer is provided on the transfer layer side, and a layer having many easy-to-slip particles and excellent handling and winding properties. Can be bonded to the antistatic layer side, so that both glossiness after transfer and handleability of the film can be easily achieved at the same time. Moreover, although the thickness of a base polyester film is not specifically limited, Preferably it is 12-188 micrometers, Most preferably, it is 30-100 micrometers.

  In the polyester film for transfer of the present invention, the haze value is preferably less than 5%, more preferably less than 3%. When the haze value exceeds 5%, the transparency of the film is impaired, so that it may be difficult to determine the defect of the printed pattern at the time of inspection of the transfer material. The haze value is, for example, adjusting the content of the lubricant contained in the base polyester film, the content of the lubricant contained in the antistatic treatment layer, and the various components contained in the antistatic treatment layer to the above-mentioned preferable ranges. And so on.

In the transfer polyester film of the present invention, the total of the metal catalyst aggregates having a major axis of 50 μm or more, coarse particles, and the number of foreign matters is preferably 50/1000 cm ² or less (including 0/1000 cm ² ). More preferably, it is 30 pieces / 1000 cm ² or less, and particularly preferably 10 pieces / 1000 cm ² or less. If the total number of foreign matters in these films exceeds 50/1000 cm ² , the foreign matter portions may form protrusions on the surface and may be transferred as defects on the transferred pattern. The method for reducing the number of these metal catalyst aggregates, coarse particles and foreign matters is not particularly limited. For example, as a polyester resin filter during film formation, the average opening is preferably 5 to 15 μm, more preferably 5 to 10 μm. It is preferable to use a filter (FSS) obtained by sintering and compressing stainless steel fibers. Further, a filter (PSS) obtained by sintering a stainless steel powder having an average opening of 10 to 30 μm is continuously filtered in this order after the filter obtained by sintering and compressing the stainless fiber, or the above 2 in one capsule. By using a composite filter (FP) that has both types of filters, catalyst agglomerates and coarse particles can be removed, and at the same time, a resin gel that is likely to occur when the film-forming edge and core are reused as recycled chips. Since chemical substances and heat-degraded substances can be removed efficiently, a large number of recycled chips can be used, and the filter life is extended, so that productivity is improved.

[Characteristic measurement method and effect evaluation method]
The characteristic measuring method and the effect evaluating method in the present invention are as follows.

(1) Surface resistivity The surface resistivity was measured by allowing the sample to stand for 24 hours under measurement conditions (temperature 25 ° C., relative humidity 65%), and then using the digital ultrahigh resistance / microammeter R8340A (Advantest Corp.) )) And applied for 10 seconds at an applied voltage of 100V.

(2) Number of metal catalyst aggregates, coarse particles and foreign matter in the base polyester film The number of metal catalyst aggregates, coarse particles and foreign matter contained in the polyester film is a group having a major axis of 50 μm or more using a polarizing microscope (40 times). Metal catalyst aggregates, coarse particles and foreign substances contained in the material polyester film were observed over 1000 cm ² and the total was counted.

(3) Film surface roughness (SRa, RMS)
Using a non-contact optical interference type three-dimensional surface roughness meter (manufactured by ZYGO, New View 200), arbitrary five points were measured under the following conditions, and the average value was obtained. The center plane average roughness (SRa) is the difference between the roughness curved surface and the center plane of the roughness curved surface in the height direction, and represents the average value of the absolute values. The root mean square roughness (RMS) is the difference between the roughness surface and the center surface of the roughness surface in the height direction, and represents the square root of the mean value of the squares.
・ Number of pixels 320 × 240 pixels ・ Scanning speed 2 μm / second ・ Magnification 20 times ・ Measurement area 0.352 mm × 0.264 mm
・ Correction Cylinder correction ・ Cutoff wavelength 0.44mm, 4.4μm
-Filter trimming ON
・ Filter type FFT FIXED
・ Filter Band Reject
・ FDA Res High
(4) Number of protrusions on the film surface Using a three-dimensional surface roughness meter (manufactured by Kosaka Laboratory, ET-30HK), measurement was performed by the stylus method under the following conditions. A histogram was prepared with the projection height Z (nm) on the horizontal axis and the COUNT number of projections on the vertical axis, and each COUNT number was defined as the number of projections at that projection height. The protrusion height Z was set to 0 nm at which the cross-sectional area of the film becomes 70% when a three-dimensional roughness curved surface is cut by a plane parallel to the reference plane of the film.
・ Needle diameter 2 (μmR)
-Needle pressure 10 (mg)
・ Measurement length 500 (μm)
・ Vertical magnification 20000 (times)
・ CUT OFF 250 (μm)
・ Measurement speed 100 (μm / s)
・ Measurement interval 5 (μm)
・ Recording number 80 ・ Hysteresis width ± 6.25 (nm)
・ Standard area 0.1 (mm ² )
(5) Glossiness and moldability of the surface of the molded product after transfer A mixture of butylated urea melamine resin and paratoluenesulfonic acid was applied to the transfer surface side of the polyester film for transfer foil by gravure coating, and 80 ° C. A release layer was formed by curing at a temperature of. Next, a release layer is formed on the release layer by gravure coating using an acrylic resin, and a metallic layer (containing 20% aluminum pigment) with vinyl resin ink is used as a pattern layer on the release layer. A black character pattern (containing 15% carbon black) is formed by gravure printing, then washed with hot water at 40 ° C. and dried, and finally an acrylic resin adhesive layer is formed by a gravure coating method to obtain a transfer material. It was.

  The obtained transfer material is vacuum-molded in a mold at a mold temperature of 220 ° C. in a mold of 50 mm × 50 mm and a maximum depth of 8 mm in an atmosphere of a temperature of 25 ° C. and a relative humidity of 30%, and then clamped. Thereafter, simultaneous molding and transfer processing was performed under an injection pressure condition of 25 MPa using acrylic resin as a molding resin.

(A) Surface glossiness The surface glossiness of 60 ° reflection in Japanese Industrial Standard (JIS) Z-8741 (2004) was measured for the obtained molded product. When the surface glossiness of the molded product was GF and the surface glossiness of the standard metal sample was GM, the following judgment was followed. Δ or more is acceptable.
○ GF ≧ GM
△ GM-20 ≦ GF <GM
× GF <GM-20
(B) Formability The formability was determined according to the following judgment. Δ or more is acceptable.
○ The percentage of defective products due to dust adhesion, whiskers, etc. is less than 0.1%.
△ The percentage of defective products due to dust adhesion, whiskers, etc. is less than 1%.
× The percentage of defective products due to dust adhesion, whiskers, etc. is 1% or more.

(6) Scratch resistance of easy-adhesive layer The easy-adhesive surface of a 1/2 inch wide roll film is applied to the fixing pin, and it is run at a speed of 2 m / min, and deposits on the fixing pin after 15 minutes are observed. The following judgment was followed. Δ or more is acceptable.
○ Deposits are hardly observed △ Slightly adhered traces × Many (7) Adhesiveness between easy-adhesion layer and release layer Butylation on the transfer surface (adhesive surface) side of polyester film for transfer foil A mixed solution of urea melamine resin and p-toluenesulfonic acid was applied by gravure coating, cured at 80 ° C. to form a release layer, and air-dried at room temperature for 1 day. On this, a grid cut was made with a cutter knife, and a cellophane tape was applied, 90 ° positive peeling was performed, the peeling state was evaluated in three stages, and the following judgment was followed. Δ or more is acceptable.
○ A release layer of 75% or more remains.
Δ 50% or more and less than 75% release layer remains.
X A release layer remains less than 50%.

(8) Average particle diameter Polyester is removed from the film by plasma low-temperature ashing to expose the particles. The treatment conditions are such that the polyester is ashed but the particles are not damaged. This is observed with a scanning electron microscope (Elionix, ESM3200), and the image of the particles is processed with an image analyzer (Carl Zeiss, IBAS2000).

(9) Haze The obtained film was subjected to the Japanese Industrial Standard (JIS) K-7105 (2004). The wavelength used is 550 nm.

  EXAMPLES 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.

Example 1
Using a composite film forming apparatus having an extruder (A), an extruder (B), and a T-die composite die, a three-layer laminated polyester film composed of the following A layer and B layer was obtained. The laminated structure is A / B / A.

First, the resin forming the A layer will be described. A slurry of 45 kg of ethylene glycol per 100 kg of high-purity terephthalic acid was charged in an esterification reaction tank in which about 123 kg of bis (hydroxyethyl) terephthalate was previously charged and maintained at a temperature of 250 ° C. and a pressure of 1.2 × 10 ⁵ Pa for 4 hours. The esterification reaction was carried out over an additional hour after the supply was completed, and the esterification reaction product was transferred to a polycondensation tank. Subsequently, 0.01 parts by weight of ethyl diethylphosphonoacetate was added to the polycondensation reaction tank to which the esterification reaction product had been transferred, and 0.04 parts by weight of magnesium acetate tetrahydrate was further added as a polymerization catalyst. Antimony trioxide (manufactured by Sumitomo Metal Mining Co., Ltd.) was added to the obtained polyester so as to be 400 ppm in terms of antimony atoms. Further, as an additive, calcium carbonate having an average particle size of 1.1 μm and a specific surface area of 300 m ² / g was added so as to be 0.06% by weight based on the polyester. Thereafter, while stirring the low polymer at 30 rpm, the reaction system was heated from 250 ° C. to 285 ° C. over 60 minutes and the pressure was reduced to 40 Pa. The time to reach the final pressure was 60 minutes. When the predetermined stirring torque was reached, the reaction system was purged with nitrogen, returned to normal pressure, the polycondensation reaction was stopped, discharged into cold water at a temperature of 20 ° C. in a strand, and immediately cut to obtain polyester pellets. . The time from the start of decompression to the arrival of the predetermined stirring torque was 3 hours.

Next, the resin forming the B layer will be described. A slurry of 45 kg of ethylene glycol per 100 kg of high-purity terephthalic acid was charged in an esterification reaction tank in which about 123 kg of bis (hydroxyethyl) terephthalate was previously charged and maintained at a temperature of 250 ° C. and a pressure of 1.2 × 10 ⁵ Pa for 4 hours. The esterification reaction was carried out over an additional hour after the supply was completed, and the esterification reaction product was transferred to a polycondensation tank. Subsequently, 0.01 parts by weight of ethyl diethylphosphonoacetate was added to the polycondensation reaction tank to which the esterification reaction product had been transferred, and 0.04 parts by weight of magnesium acetate tetrahydrate was further added as a polymerization catalyst. Antimony trioxide (manufactured by Sumitomo Metal Mining Co., Ltd.) was added to the obtained polyester so as to be 400 ppm in terms of antimony atoms. Thereafter, while stirring the low polymer at 30 rpm, the reaction system was heated from 250 ° C. to 285 ° C. over 60 minutes and the pressure was reduced to 40 Pa. The time to reach the final pressure was 60 minutes. When the predetermined stirring torque was reached, the reaction system was purged with nitrogen, returned to normal pressure, the polycondensation reaction was stopped, discharged into cold water at a temperature of 20 ° C. in a strand shape, and immediately cut to obtain polyester pellets. The time from the start of decompression to the arrival of the predetermined stirring torque was 3 hours.

  These polyester pellets forming the A layer and the B layer were vacuum dried to a moisture content of 20 ppm, respectively, and then supplied to the extruder (A) and the extruder (B), respectively, and melted at a temperature of 280 ° C. by a conventional method. Each was filtered through an 8 μm cut stainless steel fiber sintered filter (FSS) and then introduced into a T-die composite die. After merging so as to have a layer structure of A / B / A in the die, it was coextruded into a sheet shape, and this was cooled and solidified by an electrostatic contact method using a cooling drum having a surface temperature of 25 ° C. . The unstretched polyester film thus obtained was heated to a temperature of 95 ° C. and then stretched 3.5 times in the longitudinal direction at a temperature of 104 ° C. to obtain a uniaxially stretched film. Both surfaces of this uniaxially stretched film are subjected to corona discharge treatment in air to have a surface tension of 50 mN / m or more, and an easy-adhesion layer coating solution having the following composition is applied to the surface on the transfer surface side. An antistatic layer coating solution having the following composition was applied to the non-transfer surface side).

<Easily adhesive layer coating solution>
A polyester-based easy-adhesion coating liquid α1 was prepared by the following method. Copolyester resin (glass transition) comprising 70 mol% terephthalic acid as acidic component, 23 mol% isophthalic acid and 7 mol% 5-sodiumsulfoisophthalic acid, and 70 mol% ethylene glycol and 30 mol% diethylene glycol as diol components (A point: 55 degreeC) The aqueous solution which mixed the Dainippon Ink Chemical Industries Co., Ltd. product and "Beckamine" (trademark) APM as a melamine crosslinking agent so that it might become solid content ratio 95: 5. used.

<Antistatic layer coating solution>
An aqueous solution in which the following antistatic layer coating liquid A1, antistatic layer coating liquid B1 and antistatic layer coating liquid C1 were mixed at an active ingredient ratio of 20 parts by weight / 80 parts by weight / 20 parts by weight was used.
・ Antistatic coating liquid A1
An aqueous coating solution (“Denatron” (R) 5002RZ, manufactured by Nagase ChemteX Corporation) in which a composite of polyethylene dioxythiophene / polystyrene sulfonic acid and a polyester resin were dispersed in water was used.
・ Antistatic layer coating solution B1
An aqueous solution in which a polyglycerol polyglycidyl ether type epoxy crosslinking agent (“Denacol” (R) EX-512 manufactured by Nagase ChemteX Corporation) was dissolved in water was used.
・ Antistatic layer coating liquid C1
An aqueous solution in which a long-chain alkyl acrylate having the following copolymer composition was dissolved in water containing 10% by weight of isopropyl alcohol and 5% by weight of butyl cellosolve was used.

(Copolymerization component)
Methacrylic acid 40 parts by weight Stearyl methacrylate 60 parts by weight N-methylol acrylamide 2 parts by weight Anionic reactive emulsifier 2 parts by weight Anionic reactive emulsifier includes “Eleminol” (registered trademark) JS-2 (Sanyo Chemical Industries ( Product).

  While holding both ends of the uniaxially stretched laminated polyester film applied to both sides with clips, the tenter is led to a preheating zone at a temperature of 115 ° C. in the tenter, and then continuously at a heating zone at a temperature of 121 ° C. perpendicular to the longitudinal direction. The film was stretched 4.1 times in the direction (lateral direction). Subsequently, a heat treatment at a temperature of 230 ° C. was performed in a heat treatment zone in the tenter, and further a relaxation treatment was performed in a lateral direction of 2.2% at a temperature of 213 ° C., followed by a further relaxation of 1.3% at a temperature of 166 ° C. Then, the film was uniformly cooled and wound up to obtain a film for transfer foil having a total thickness of 38 μm and a width of 6.9 m. The results are shown in Tables 1 and 2. Stable antistatic properties were exhibited, and surface smoothness and surface gloss after molding were also good.

(Examples 2 to 4)
A film for transfer foil was obtained in accordance with Example 1, except that the following antistatic layer coating solution and easy-adhesion layer coating solution were used and the conditions shown in Tables 1 and 2 were used.
・ Antistatic layer coating liquid A2
An aqueous coating liquid (“Baytron P” (registered trademark) manufactured by Bayer) in which a composite of polyethylene dioxythiophene / polystyrene sulfonic acid was dispersed in water was used.
・ Antistatic layer coating liquid C2
An aqueous solution in which a long-chain alkyl acrylate having the following copolymer composition was dissolved in water containing 10% by weight of isopropyl alcohol and 5% by weight of butyl cellosolve was used.
(Copolymerization component)
Methacrylic acid 40 parts by weight Behenyl methacrylate 60 parts by weight N-methylol acrylamide 2 parts by weight Anionic reactive emulsifier 2 parts by weight Anionic reactive emulsifier is “ELEMINOL” (registered trademark) JS-2 (Sanyo Chemical Industries, Ltd.) Made).
・ Antistatic coating liquid D1
Polydiallyldimethylammonium chloride (average molecular weight: about 30000) was used.
・ Antistatic coating liquid E1
A melamine cross-linking agent, “Beccamin” (registered trademark) J101, manufactured by Dainippon Ink & Chemicals, Inc. was used.
-Easy adhesive layer coating liquid α2
A polyester-based easy-adhesion coating liquid α2 was prepared by the following method. (1) fluorinated surfactant, (2) copolymer polyester (glass) having a copolymer composition of terephthalic acid / 5-sodium sulfoisophthalic acid // ethylene glycol (molar ratio 87.5 / 12.5 // 100) (Transition point 40 ° C.), (3) copolymer polyester having a copolymer composition of isophthalic acid / 5-sodium sulfoisophthalic acid // ethylene glycol / diethylene glycol (molar ratio 93/7 // 10/90) (glass transition point 18 (2) / (3) is mixed to a solid content weight ratio of 70/30, diluted with water to a solid content concentration of 4% by weight, and (1) is applied. An aqueous coating solution added at 0.0003% by weight with respect to the whole solution was used.

  In Examples 2 and 3, a single layer T-die was used to form a single film. In Example 3, the elemental titanium is 5 ppm with respect to the polyester that can be obtained by the simultaneous biaxial stretching method and obtain an ethylene glycol solution of the citrate chelate titanium compound prepared as follows as a polymerization catalyst. Thus added polyester pellets were used. The resulting polyester pellets had an intrinsic viscosity of 0.63 dl / g, a carboxyl end group content of 42 equivalents / ton, a glass transition temperature (Tg) of 78 ° C., and a cyclic trimer content of 1.1% by weight.

(Method for synthesizing citric acid chelate titanium compound)
In a 1 L flask equipped with a stirrer, a condenser, and a thermometer, 132.5 g (0.63 mol) of citric acid monohydrate was dissolved per 92.8 g of hot water. To this stirred solution, 72.0 g (0.25 mol) of titanium tetraisopropoxide was added from a dropping funnel. The mixture was heated to reflux for 1 hour to produce a cloudy solution from which the isopropanol / water mixture was distilled under vacuum. The product was cooled to a temperature of 20 ° C. and to the stirred solution was added 94.86 g (0.76 mol) NaOH 32 wt / wt% aqueous solution via a dropping funnel. The resulting product was filtered and then mixed with 125.54 g (2 mol) of ethylene glycol and heated under vacuum to remove isopropanol / water to give a slightly cloudy, pale yellow product (Ti content 3.85% by weight) was obtained. Moreover, in Example 4, it was set as the double-layer film of A / B. The A layer is the transfer surface side.

The results are shown in Tables 1 and 2. As is clear from the table, the following results were obtained.
Example 2: The surface smoothness and antistatic property on the transfer surface side were good. Although the adhesion between the easy adhesion layer and the release layer was slightly inferior, it was at a usable level.
Example 3: Although the surface smoothness and antistatic property were slightly inferior, they were usable levels. Moreover, there were few surface scratches by the simultaneous biaxial stretching method, and the coating property was good. Further, the use of the titanium-based catalyst resulted in few internal foreign matters and good appearance.
Example 4: Both surface smoothness and antistatic properties were good. In particular, the level of antistatic property was excellent. Although the haze was slightly high and the adhesion between the easy-adhesion layer and the release layer was slightly inferior, it was at a usable level.

(Comparative Examples 1-4)
As shown in Tables 3 and 4, a 14 μm cut stainless steel powder filter (FSS) was used as the polyester film resin filter, the following antistatic layer coating solution and easy adhesion layer coating solution were used, and Tables 3 and 4 below. A transfer foil film was obtained according to Example 1 except that the conditions were used.
・ Antistatic coating solution D2
An aqueous dispersion in which particles of an acrylic resin (glass transition point 40 ° C.) having the following copolymer composition were dispersed in water was used.
(Copolymerization component)
Methyl methacrylate 65 mol%
Ethyl acrylate 35 mol%
Acrylic acid 1 mol%
N-methylolacrylamide 2 mol%
・ Antistatic coating liquid E2
A melamine cross-linking agent, “Nikalac” (registered trademark) MW12LF, manufactured by Sanwa Chemical Co., Ltd. was used.
・ Antistatic coating solution F1
An aqueous solution in which polystyrene sulfonate ammonium salt (weight average molecular weight: 10,000) was dissolved in water was used.
・ Antistatic layer coating G1
An aqueous solution comprising a nonionic polyethylene wax aqueous dispersion (wax softening point: 140 ° C., average particle size 87 nm) was used.
・ Antistatic layer coating G2
An oxidized polyethylene aqueous dispersion (Johnson (registered trademark), manufactured by Johnson Polymer Co., Ltd.) was used.
・ Easily adhesive layer coating solution β1
An acrylic easy-adhesion coating solution β1 was prepared by the following method. An aqueous solution in which the modified acrylic emulsion resin and the oxazoline crosslinking agent “Epocross WS500” (registered trademark) (manufactured by Nippon Shokubai Co., Ltd.) were mixed at an active ingredient ratio of 100 parts by weight / 10 parts by weight was used.
・ Easily adhesive layer coating solution β2
An acrylic easy-adhesion coating liquid β2 was prepared by the following method. An aqueous solution in which the antistatic coating liquid D2 and the antistatic coating liquid E2 were mixed at an active ingredient ratio of 100 parts by weight / 5 parts by weight was used.
・ Easily adhesive layer coating solution β3
A polyurethane-based easy-adhesive coating solution β3 was prepared by the following method. A coating agent obtained by adding 6 parts by weight of a melamine-based crosslinking agent to 100 parts by weight of a self-emulsifiable polyurethane polyurea resin was used.

  In Comparative Examples 2 and 4, a single layer T die die was used to form a single film.

  The results are shown in Tables 3 and 4. As is clear from the table, in Comparative Examples 1 to 4, the surface roughness, the surface glossiness of the molded product, the antistatic property, the moldability, the easy adhesion, the number of internal foreign matters and the haze are inferior, and the desired function In order to demonstrate, the level was not achieved.

  The polyester film for transfer foil according to the present invention is excellent in anti-static properties, easy adhesion and surface smoothness, especially in in-mold molding applications where high design properties are required. It is useful because it can significantly improve productivity and product quality.

Claims (11)

  A polyester film for transfer foil, characterized in that at least the surface on the transfer surface side has a center plane average roughness (SRa) value of 15 nm or less and the number of projections of 200 nm or more is 1% or more of the total number of projections. .   2. The polyester film for transfer foil according to claim 1, wherein the number of projections of 200 nm to 800 nm is 3% to 20% of the total number of projections at least on the surface of the transfer surface.   3. The polyester film for transfer foil according to claim 1, wherein the root mean square roughness (RMS) value is 20 nm or less at least on the surface on the transfer surface side.   The polyester film for transfer foil according to claim 1, further comprising an antistatic layer on the surface opposite to the transfer surface.   The polyester film for transfer foil according to claim 4, wherein the antistatic layer is a coating layer formed of a component capable of being applied with an aqueous coating liquid and stretched in at least one direction. 6. The transfer foil according to claim 4, wherein the antistatic layer contains polythiophene and / or a polythiophene derivative, and the surface specific resistance of the surface of the antistatic layer is 1 × 10 ¹⁰ Ω / □ or less. Polyester film.   The polyester film for transfer foil according to claim 1, further comprising an easily adhesive layer on the transfer surface side.   8. The polyester film for transfer foil according to claim 7, wherein the easy-adhesion layer is a coating layer formed of a component capable of being applied with an aqueous coating liquid and stretched in at least one direction.   The polyester film for transfer foil according to claim 7 or 8, wherein the easy adhesion layer contains a polyester resin.   The polyester film for transfer foil according to any one of claims 1 to 9, wherein a titanium-based compound is used as a polymerization catalyst for the polyester constituting the polyester film.   The polyester film for transfer foil according to claim 1, wherein the polyester film is a simultaneous biaxially stretched film.