JP4904069B2 - Polyester film for in-mold transfer - Google Patents

Description

  The present invention relates to an in-mold transfer polyester film useful as a support film for an in-mold transfer transfer foil (in-mold transfer foil) that is transferred and printed simultaneously with molding in injection molding or the like.

  Conventionally, as a transfer foil for in-mold, a laminated film in which a polyester film is used as a base film, a release layer (medium layer) is provided on the surface of the base film, and a printing layer is further coated thereon is used.

  This in-mold transfer foil is peeled off and separated between the release layer surface and the print layer surface after molding and transfer. That is, after molding transfer, the printed layer is adhered to the surface of the molded product and taken out as a product, and the release layer is removed after molding in a state of being laminated on the base film.

  Conventional in-mold transfer foils often have insufficient adhesion between the release layer and the base film, and insufficient release properties between the release layer surface and the print layer surface. In the subsequent peeling treatment, peeling often occurs between the release layer surface and the base film surface, and the release layer remains on the surface of the molded product together with the printing layer. Such a defect is often caused by peeling of the release layer and the base film due to distortion when the laminated film is deformed in in-mold transfer.

  In order to improve this point, a method of improving the adhesion between the base film and the release layer by providing an adhesive layer made of polyester resin, polyurethane resin, acrylic resin, etc. between the base film and the release layer is effective. is there. However, the resin constituting the adhesive layer is usually one having low solvent resistance from the viewpoint of adhesive properties. For this reason, when the release layer is applied, the adhesive layer dissolved or softened by the solvent is partially peeled off by the release layer coating tool, and the adhesive strength between the release layer and the base film decreases. A new problem arises. Moreover, the film which laminated | stacked the contact bonding layer is easy to adhere | attach between films (blocking resistance is bad), and also has the fault which causes the handling property at the time of laminating | stacking a release layer further on this film.

  In recent years, in-mold transfer requires higher productivity, and attempts have been made to improve the molding speed. When handling the in-mold transfer foil, sticking of the transfer foils due to electrification and adhesion of dust and dust to the surface of the transfer foil may occur, which may reduce productivity. In addition, the mold is contaminated with oligomers generated from the polyester film during molding, and the mold is frequently washed, causing a decrease in productivity.

  An antistatic agent is applied to the surface of the film to prevent the usual dust and dirt from adhering to prevent the adhesion. However, a general antistatic agent is an ionic compound and is weak against water. Washing water is used to remove unnecessary materials in processes such as printing of in-mold transfer foil, and the antistatic layer is washed. There is a problem of elution with water. Further, by laminating the antistatic layer on the surface opposite to the printing surface, there is a problem that the antistatic layer and the printing layer are stuck, and the handling property is lowered. In order to prevent this sticking, a release component may be added to the antistatic layer, but the compatibility with the antistatic agent is poor and the appearance of the coating becomes uneven, which may be a problem.

JP-A-6-115295 JP 2004-223800 A JP 2004-174975 A JP 2004-58648 A

  The present invention is for solving the problems of the prior art. That is, the object of the present invention is to have excellent antistatic properties from the process of creating a transfer foil for in-mold to molding transfer, and there is no sticking between the antistatic layer and the printing layer, and the antistatic layer An object of the present invention is to provide a base film for an in-mold transfer foil that has good coating uniformity and excellent adhesion to a release layer during in-mold transfer molding.

さらにシリコーン化合物および界面活性剤を含有し、シリコーン化合物は反応基を有するシリコーン化合物であって、該反応基がアミノ基を含む有機基、エポキシ基を含む有機基、カルボン酸基を含む有機基、シラノール基もしくは加水分解によりシラノール基を生成する有機基から選ばれる有機基であり、界面活性剤は分岐構造を有するフッ素化合物であり、該帯電防止層が水性塗液をフィルムに塗布して形成されることを特徴とする、インモールド転写用ポリエステルフィルムである。 That is, the present invention comprises a polyester film and an antistatic layer provided on one side thereof, and the antistatic layer contains a cationic polymer having a unit represented by the following formula (1) as an antistatic agent,

Further containing a silicone compound and a surfactant, the silicone compound is a silicone compound having a reactive group, and the reactive group includes an organic group containing an amino group, an organic group containing an epoxy group, an organic group containing a carboxylic acid group, An organic group selected from a silanol group or an organic group that generates a silanol group by hydrolysis, the surfactant is a fluorine compound having a branched structure, and the antistatic layer is formed by applying an aqueous coating liquid onto a film. It is the polyester film for in-mold transfer characterized by the above-mentioned.

  According to the present invention, the antistatic layer has excellent antistatic properties from the in-mold transfer foil preparation process to molding transfer, and there is no sticking between the antistatic layer and the printing layer, and the antistatic layer is uniformly applied. Therefore, it is possible to provide a base film for a transfer foil for in-mold that has good properties and excellent adhesion to a release layer at the time of in-mold transfer molding.

Hereinafter, the present invention will be described in detail.
[Polyester film]
In the present invention, the polyester constituting the polyester film is a linear saturated polyester synthesized from an aromatic dibasic acid or an ester-forming derivative thereof and a diol or an ester-forming derivative thereof. Specific examples of such polyester include polyethylene terephthalate, polyethylene isophthalate, polybutylene terephthalate, poly (1,4-cyclohexylenedimethylene terephthalate), and polyethylene-2,6-naphthalate.

The polyester used in the polyester film may be a copolymer of these polyesters, and the polyester is the main component (for example, a component of 80 mol% or more), and other types in a small proportion (for example, 20 mol% or less). It may be blended with the above resin. Polyethylene terephthalate is particularly preferable as the polyester because it has a good balance between mechanical properties and moldability.
The polyester can also contain a colorant, an antistatic agent, an antioxidant, an organic lubricant, and a catalyst.

  In the present invention, the polyester film may confirm the printed layer of the transfer foil for in-mold from the opposite side, transparency is required, and higher transparency is preferable. In recent years, high-definition printing has been demanded, and a flatter surface is preferable.

  In the production of such a polyester film, for example, the above polyester is melt-extruded into a film shape, cooled and solidified with a casting drum to form an amorphous unstretched film, and a temperature of 60 to 130 ° C., preferably 90 to 125 ° C., in the longitudinal direction. The film is stretched 0 to 4.0 times, preferably 2.5 to 3.5 times, and then transversely at a temperature of 60 to 130 ° C., preferably 90 to 125 ° C., and 2.0 to 4.0 times, preferably 3. It is preferable to stretch 0 to 4.0 times. In addition, it is preferable that the area magnification after biaxial stretching is 13 or less. In addition, it is possible to use a method in which stretching in one direction is performed in two or more stages. However, after stretching in the biaxial direction, an intermediate heat treatment is performed, and then the same direction as the first stage and / or the same as the second stage. It may be stretched in the direction. In these cases, the final draw ratio is preferably in the above-described range.

  The heat setting treatment after stretching is preferably performed within a time period of 1 to 30 seconds within a temperature higher than the final stretching temperature and not higher than the melting point. For example, a polyethylene terephthalate film is preferably heat-set by selecting from a temperature of 150 to 250 ° C. and a time of 2 to 30 seconds. At that time, it may be performed under a limited contraction or expansion within 20%, or under a constant length, or may be performed in two or more stages.

  The thickness of the polyester film is preferably 12 to 100 μm, particularly preferably 25 to 75 μm, in order to obtain the necessary strength from the viewpoints of handleability, moldability and transparency when used as an in-mold transfer. .

[Antistatic layer]
In the present invention, an antistatic layer containing a silicone compound and a surfactant is provided on one side of the polyester film. A fluorine compound having a branched structure is used as the surfactant. The silicone compound is preferably a silicone compound having a reactive group. When a silicone compound having no reactive group is used as the silicone compound, transfer to the back surface of the film occurs, and transfer defects to the molded product of the printed layer may occur, which is not preferable.

[Silicone compound]
In the present invention, the silicone compound having a reactive group is a silicone compound having a reactive group directly bonded to a silicon atom. The reactive group here is an organic group containing an amino group, an organic group containing an epoxy group, an organic group containing a carboxylic acid group, a silanol group or an organic group that generates a silanol group by hydrolysis, and a reaction selected from these groups. Contains one or more groups. Different reactive groups may coexist or a mixture of silicone compounds having different reactive groups may be used.

  The molecular weight of the silicone compound having a reactive group is preferably 1000 to 500,000. If it is less than 1000, transfer to the back surface tends to be unfavorable, and if it exceeds 500,000, the viscosity becomes high and handling is difficult.

  Illustrative of reactive groups, organic groups containing amino groups include primary aminoalkyl groups such as 3-aminopropyl group, 3-amino-2-methyl-propyl group, 2-aminoethyl group, and the like, 2) N- ( Examples thereof include organic groups having primary and secondary amino groups such as 2-aminoethyl) -3-aminopropyl group and N- (2-aminoethyl) -2-aminoethyl group.

  Examples of the organic group containing an epoxy group include a glycidoxyalkyl group such as γ-glycidoxypropyl group, β-glycidoxyethyl group, γ-glycidoxy-β-methyl-propyl group, 2-glycidoxycarbonyl- Examples thereof include glycidoxycarbonylalkyl groups such as ethyl group and 2-glycidoxycarbonyl-propyl group.

  Examples of organic groups that generate silanol groups by hydrolysis include alkoxy groups such as methoxy, ethoxy, butoxy, and 2-ethylhexyloxy, methoxy-β-ethoxy, ethoxy-β-ethoxy, and butoxy-β. N-alkylamino groups such as alkoxy-β-ethoxy groups such as ethoxy groups, acyloxy groups such as acetoxy groups and propoxy groups, N-alkylamino groups such as methylamino groups, ethylamino groups and butylamino groups, N such as dimethylamino groups and diethylamino groups , N-dialkylamino group, imidazole group, pyrrole group and other heterocyclic groups containing nitrogen can be exemplified.

  The silicone compound having a reactive group is preferably contained in the antistatic layer in an amount of 1 to 50% by weight. If it is less than 1% by weight, sticking to the printed layer occurs, which is not preferable, and if it exceeds 50% by weight, the uniformity of the coating film is deteriorated.

[Surfactant]
As the fluorine compound having a branched structure used as a surfactant, a compound in which a hydrophilic group is bonded to a fluorine-containing carbon group having a branched structure is used. For example, a surfactant derived from a hexafluoropropene oligomer and having a branched perfluorohexenyl group, perfluorononenyl group, or the like can be used.

Examples of the hydrophilic group include polyoxyalkylene, sulfonic acid sodium salt, phosphonic acid, carboxylic acid metal salt, quaternary ammonium salt, and the like, and are bonded to the fluorocarbon group through, for example, an ether bond. In order to prevent the coating liquid component from aggregating when other ionic compounds are used as the coating liquid component, it is preferable to use a nonionic group as the hydrophilic group, and a polyoxyalkylene group is preferable.
As the surfactant preferably used, for example, a fluorosurfactant manufactured by Neos Co., Ltd. (aftergent series such as aftergent 250) can be exemplified.

  The surfactant is preferably contained in the antistatic layer in an amount of 0.1 to 5% by weight. If it is less than 0.1% by weight, the coating uniformity is not improved, and it is not preferable. If it exceeds 5% by weight, the surfactant moves to the back surface, and the adhesion of the easy-adhesion layer may be lowered.

[Antistatic agent]
The antistatic layer contains an antistatic agent. The antistatic agent is preferably a cationic polymer, more preferably a polymer having a unit represented by the following formula.

In this polymer, it is preferable to copolymerize a non-reactive monomer component and a reactive monomer component in order to improve the film forming property, cohesive strength, water resistance and chemical resistance of the coating film.
Non-reacting monomer components include alkyl acrylates and alkyl methacrylates (the alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl, 2-ethylhexyl, Cyclohexyl group, etc.), styrene, and α-methylstyrene. Reactive monomer components include hydroxy-containing monomers such as 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, and 2-hydroxypropyl methacrylate; epoxy groups such as glycidyl acrylate, glycidyl methacrylate, and allyl glycidyl ether Monomers: carboxy groups such as acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, styrenesulfonic acid and salts thereof (sodium salt, potassium salt, ammonium salt, tertiary amine salt, etc.) or salts thereof Monomers containing: acrylamide, methacrylamide, N-alkyl acrylamide, N-alkyl methacrylamide, N, N-dialkyl acrylamide, N, N-dialkyl methacrylate (Alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl, 2-ethylhexyl, cyclohexyl, etc.), N-alkoxyacrylamide, N-alkoxymethacrylamide, N, N-dialkoxyacrylamide, N, N-dialkoxymethacrylamide (alkoxy groups include methoxy, ethoxy, butoxy, isobutoxy, etc.), acryloylmorpholine, N-methylolacrylamide, Monomers containing amide groups such as N-methylol methacrylamide, N-phenyl acrylamide, N-phenyl methacrylamide; monomers of acid anhydrides such as maleic anhydride and itaconic anhydride; Isocyanates such as vinyl isocyanate and allyl isocyanate It can be exemplified containing monomer.

  In order to further improve the water resistance and cohesion of the antistatic layer, the antistatic layer preferably further contains a crosslinking agent. As a crosslinking agent, an epoxy crosslinking agent, an oxazoline crosslinking agent, a melamine crosslinking agent, an isocyanate crosslinking agent, and a coupling agent can be illustrated.

  Examples of the epoxy crosslinking agent include polyepoxy compounds, diepoxy compounds, monoepoxy compounds, and glycidylamine compounds. Examples of the polyepoxy compound include sorbitol, polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, diglycerol polyglycidyl ether, triglycidyl tris (2-hydroxyethyl) isocyanate, glycerol polyglycidyl ether, trimethylol. Propane polyglycidyl ether can be exemplified.

  Examples of the diepoxy compound include neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, resorcin diglycidyl ether, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, and polypropylene glycol diester. Examples thereof include glycidyl ether and polytetramethylene glycol diglycidyl ether.

  Examples of the monoepoxy compound include allyl glycidyl ether, 2-ethylhexyl glycidyl ether, phenyl glycidyl ether, and examples of the glycidyl amine compound include N, N, N ′, N ′,-tetraglycidyl-m-xylylenediamine, 1,3. -Bis (N, N-diglycidylamino) cyclohexane can be exemplified.

  The oxazoline compound is preferably a polymer containing an oxazoline group. This can be obtained by polymerization of an addition-polymerizable oxazoline group-containing monomer or polymerization of this with another monomer. Addition polymerizable oxazoline group-containing monomers include 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, 2-vinyl-5-methyl-2-oxazoline, 2-isopropenyl-2-oxazoline, Examples include 2-isopropenyl-4-methyl-2-oxazoline and 2-isopropenyl-5-ethyl-2-oxazoline. Among them, 2-isopropenyl-2-oxazoline is industrially available. It is easy and suitable. The other monomer may be any monomer that can be copolymerized with an addition-polymerizable oxazoline group-containing monomer, such as alkyl acrylate, alkyl methacrylate (the alkyl group includes a methyl group, an ethyl group, an n-propyl group, an isopropyl group, (meth) acrylic acid esters such as n-butyl group, isobutyl group, t-butyl group, 2-ethylhexyl group, cyclohexyl group); acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, Unsaturated carboxylic acids such as styrenesulfonic acid and its salts (sodium salt, potassium salt, ammonium salt, tertiary amine salt, etc.); Unsaturated nitriles such as acrylonitrile, methacrylonitrile; acrylamide, methacrylamide, N-alkyl Acrylamide, N-alkyl methacryl Mido, N, N-dialkylacrylamide, N, N-dialkyl methacrylate (alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl, 2- Ethyl hexyl group, cyclohexyl group, etc.); vinyl esters such as vinyl acetate and vinyl propionate; vinyl ethers such as methyl vinyl ether and ethyl vinyl ether; α-olefins such as ethylene and propylene; vinyl chloride and chloride Examples include halogen-containing α, β-unsaturated monomers such as vinylidene and vinyl fluoride; α, β-unsaturated aromatic monomers such as styrene and α-methylstyrene.

  The melamine compound is preferably a compound obtained by reacting methylol melamine derivative obtained by condensing melamine and formaldehyde with ether such as methyl alcohol, ethyl alcohol, isopropyl alcohol or the like as a lower alcohol and a mixture thereof. Examples of the methylol melamine derivative include monomethylol melamine, dimethylol melamine, trimethylol melamine, tetramethylol melamine, pentamethylol melamine, hexamethylol melamine and the like.

  Isocyanate compounds include, for example, tolylene diisocyanate, diphenylmethane-4,4′-diisocyanate, metaxylylene diisocyanate, hexamethylene-1,6-diisocyanate, 1,6-diisocyanate hexane, an adduct of tolylene diisocyanate and hexane triol, Tolylene diisocyanate and trimethylolpropane adduct, polyol-modified diphenylmethane-4,4'-diisocyanate, carbodiimide-modified diphenylmethane-4,4'-diisocyanate, isophorone diisocyanate, 1,5-naphthalene diisocyanate, 3,3'-vitrylene- Examples include 4,4 ′ diisocyanate, 3,3 ′ dimethyldiphenylmethane-4,4′-diisocyanate, and metaphenylene diisocyanate. That.

As the coupling agent, it is possible to use, for example, silane coupling agent, which is represented by the general formula YRSiX _3. Here, Y is an organic functional group such as vinyl group, epoxy group, amino group, mercapto group, R is an alkylene group such as methylene, ethylene, propylene group, X is a hydrolyzable group such as methoxy group, ethoxy group, and the like. It is an alkyl group. Y is particularly preferably an epoxy group. Preferred coupling agents are γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, and γ-glycidoxypropylmethyldiethoxysilane.

  The crosslinking agent is preferably contained in the antistatic layer in an amount of 5 to 50% by weight. If it is less than 5% by weight, the cohesive force of the antistatic layer becomes low, and transfer to the back surface of the antistatic layer may occur, which is not preferable. If it exceeds 50% by weight, the film forming property of the antistatic layer is deteriorated, and the coating appearance is deteriorated. It has suitable antistatic properties.

  The antistatic layer preferably contains fine particles. The average particle diameter of the fine particles is preferably 20 to 100 nm, more preferably 40 to 80 nm. When the average particle diameter is less than 20 nm, the blocking property when the film is wound and the winding property of the film are inferior. When the average particle diameter exceeds 100 nm, omission of fine particles and transparency of the antistatic layer may deteriorate, which is not preferable.

The final dry coating thickness of the antistatic layer is preferably 0.01 to 0.1 μm, more preferably 0.01 to 0.06 μm. If the thickness is less than 0.01 μm, the antistatic property becomes insufficient, which is not preferable, and if it exceeds 0.1 μm, blocking with the in-mold transfer foil is likely to occur, which is not preferable.
The surface specific resistance of the antistatic agent layer is preferably 1 × 10 ¹³ Ω / □ or less. If it exceeds 1 × 10 ¹³ Ω / □, sufficient antistatic properties cannot be obtained.

[Easily adhesive layer]
An easy adhesion layer is provided on the other surface of the polyester film. For the easy-adhesion layer, it is preferable to use a polymer binder made of a copolyester so that the release layer can have high adhesion. As the copolyester, those having a glass transition point (Tg) of 40 to 85 ° C, preferably 45 to 80 ° C are used. A film obtained when the Tg of the copolymerized polyester is less than 40 ° C. is inferior in heat resistance and blocking resistance. This polyester can be obtained using any two or more of the following dicarboxylic components or any two or more of the diol components. Dicarboxylic acid components include terephthalic acid, isophthalic acid, phthalic acid, phthalic anhydride, 2,6-naphthalenedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, adipic acid, sebacic acid, trimellitic acid, pyromellitic acid, dimer Acid, 5-sodium sulfoisophthalic acid can be used. Examples of the diol component include ethylene glycol, 1,4-butanediol, diethylene glycol, dipropylene glycol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, xylene glycol, dimethylolpropane, and poly (ethylene oxide) glycol. Poly (tetramethylene oxide) glycol can be used. The copolymer polyester may contain an unsaturated polybasic acid component such as maleic acid or itaconic acid, or a hydroxycarboxylic acid component such as p-hydroxybenzoic acid, if it is in a slight amount.

The copolymerized polyester is preferably used in the form of an aqueous dispersion or an emulsion to form an easy-adhesion layer.
The easy-adhesion layer preferably contains fine particles. The average particle diameter of the fine particles is preferably 20 to 100 nm, more preferably 40 to 80 nm. When the average particle diameter is less than 20 nm, the blocking property when the film is wound and the winding property of the film are inferior. If the average particle diameter exceeds 100 nm, the lack of fine particles and the transparency of the easy-adhesion layer may deteriorate, which is not preferable.

The content of the fine particles is preferably 30% by weight or less. If it exceeds 30% by weight, the strength of the coating layer is lowered, and troubles such as scraping of the coating film occur in a later step, which is undesirable.
Examples of the fine particles include silicon oxide, aluminum oxide, magnesium oxide, calcium carbonate, kaolin, talc, titanium oxide, zinc oxide, barium sulfate, zirconium oxide, titanium oxide, tin oxide, antimony trioxide, carbon black, and disulfide. Inorganic fine particles such as molybdenum, and organic fine particles composed of heat-resistant resins such as acrylic cross-linked polymers, styrenic cross-linked polymers, silicone resins, fluororesins, benzoguanamine resins, phenol resins, nylon resins, etc. it can. Among these, silicon oxide, cross-linked polystyrene resin particles, and cross-linked acrylic resin particles are particularly preferable from the viewpoint of handling and stability in the coating liquid and dispersibility in the coating film.

  The final dry coating thickness of the easy-adhesion layer is preferably 0.05 to 0.3 μm, more preferably 0.07 to 0.2 μm. If the thickness of the coating film is less than 0.05 μm, the adhesiveness becomes insufficient, which is not preferable, and if it exceeds 0.3 μm, blocking tends to occur, which is not preferable.

[Production method]
The composition used for coating the antistatic layer and the easy-adhesion layer is preferably used in the form of an aqueous coating solution such as an aqueous solution, an aqueous dispersion or an emulsified solution and applied onto the film. If necessary, other resins than the above-described composition, such as a colorant, a surfactant, and an ultraviolet absorber, may be added.

  The solid content concentration of the aqueous coating solution used for forming the antistatic layer and the easy-adhesion layer is usually 20% by weight or less, preferably 1 to 10% by weight. If it is less than 1% by weight, the coatability to the polyester film may be insufficient, and if it exceeds 20% by weight, the stability of the coating liquid and the appearance of the antistatic layer or the easy-adhesion layer may be deteriorated. Absent.

  Application of the aqueous coating solution to the polyester film can be carried out at any stage, but it is preferably carried out during the production process of the polyester film, and is further applied to the polyester film before the completion of orientational crystallization. Is preferred.

  Here, the polyester film before the crystal orientation is completed is an unstretched film, a uniaxially oriented film in which the unstretched film is oriented in either the longitudinal direction or the transverse direction, and further in two directions, the longitudinal direction and the transverse direction. And the like that have been oriented at a low magnification (biaxially stretched film before being finally re-stretched in the machine direction or the transverse direction to complete orientation crystallization). In particular, it is preferable to apply the aqueous coating liquid of the above composition to an unstretched film or a uniaxially stretched film oriented in one direction, and perform longitudinal stretching and / or lateral stretching and heat setting as it is.

  When applying an aqueous coating liquid to a film, as a pretreatment for improving the coating property, the film surface is subjected to physical treatment such as corona surface treatment, flame treatment, plasma treatment, etc., or chemically combined with the composition. It is preferable to use an inert surfactant in combination. Such a surfactant improves the function of promoting the wetting of the aqueous coating liquid onto the polyester film and the stability of the coating liquid. For example, polyoxyethylene-fatty acid ester, sorbitan fatty acid ester, glycerin fatty acid ester, fatty acid metal Anionic and nonionic surfactants such as soaps, alkyl sulfates, alkyl sulfonates, and alkyl sulfosuccinates can be mentioned. The surfactant is preferably contained in an amount of 1 to 10% by weight in the composition forming the coating film.

  As a coating method, any known coating method can be applied. For example, a roll coating method, a gravure coating method, a roll brush method, a spray coating method, an air knife coating method, an impregnation method, a curtain coating method and the like can be used alone or in combination.

Hereinafter, the present invention will be described in more detail with reference to examples.
Various physical properties were evaluated by the following methods.

(1) Adhesiveness of antistatic layer The surface of the antistatic layer of the film was rubbed with a finger 10 cm long for 10 reciprocations, the missing state of the coating film was observed, and the antistatic layer adhesion was evaluated according to the following criteria. Up to A satisfies practical performance.
A: No change A: Some change on the surface B: Half of the scratched area is missing C: Most of the scratched area is missing

(2) Antistatic property The surface resistivity of the antistatic layer surface of the sample film is 1 at an applied voltage of 100 V under the conditions of a measurement temperature of 23 ° C. and a measurement humidity of 60% using a specific resistance measuring instrument manufactured by Takeda Riken. The surface specific resistance value (Ω / □) after a minute was measured. The surface specific resistance value is preferably 1 × 10 ¹³ [Ω / □] or less, more preferably 1 × 10 ¹² or less.

(3) Uniformity of coating The coated film was visually observed for appearance under a fluorescent lamp and evaluated according to the following criteria. Up to A satisfies practical performance.
A: Uniform coating B: Partial plaque occurrence C: Overall plaque occurrence

(4) Release layer adhesiveness A 1 μm-thick release layer (medium layer) film is formed by applying a methyl ethyl ketone / toluene solution of melamine resin on the coating surface of the film, and gold as a laminate by hot pressing. The state of the release layer when it was molded on the mold was observed and evaluated according to the following criteria. Up to A satisfies practical performance.
A: No change B: Partially peeled C: Whole peeled

(5) Blocking resistance In order to evaluate the blocking resistance between the antistatic layer surface of the sample film and the printing surface of the in-mold transfer foil, a stamping foil pigment foil (COLORIT) P type (manufactured by Kurz) is used. The antistatic surface and the printing surface were combined, the temperature was 60 ° C., the pressure was 1 kg / cm ^2, and the environment was maintained for 24 hours. The blocking state between the antistatic layer surface and the label seal surface was observed, and It was evaluated with. Up to A satisfies practical performance.
A: No change A: Some change on the surface B: Partially peeled C: Fully peeled

(6) Layer thickness The film was fixed with an embedding resin, the cross section was cut with a microtome, stained with 2% osmic acid at 60 ° C. for 2 hours, and the layer was examined using a transmission electron microscope (JEM2010 manufactured by JEOL Ltd.). The thickness was measured.

(7) Back surface transferability The easy adhesion surface and the antistatic layer surface are overlapped on the sample film, and after treatment at a temperature of 50 ° C. and a pressure of 50 kg / cm ² for 24 hours, the surface of the easy adhesion layer is changed to 38 to 40 mN / m. The wetting state of the wetting tension magic was observed and evaluated according to the following criteria. Up to B satisfies the practical performance.
A +: Can be applied evenly A: Partially repels B: Repels about half C: Repels as a whole

[Example 1]
Molten polyethylene terephthalate ([η] = 0.64 dl / g, Tg = 78 ° C.) containing 0.005 wt% of silicon oxide fine particles having an average particle diameter of 2 μm is extruded from a die and cooled by a cooling drum by a conventional method. After forming an unstretched film and then stretching in the longitudinal direction by a factor of 3.4, each of the coating liquids (easily adhesive layer: 6% by weight, antistatic layer: 3% by weight) composed of the coating layer constituents shown in the table is applied to each roll coater. And evenly applied.

[Example 2, Comparative Examples 1 and 2]
The same procedure as in Example 1 was performed except that the composition of the antistatic layer was changed as shown in Table 1. The evaluation results are summarized in Table 1.

[Comparative Example 3]
The same procedure as in Example 1 was performed except that the easy adhesion layer and the antistatic layer were not provided.
Subsequently, this coated film was subsequently dried at 105 ° C., stretched 3.5 times at 140 ° C., heat-set at 230 ° C., and having a coating film shown in Table 1 (thickness: 38 μm). ) The evaluation results are summarized in Table 1.

Cationic polymer:
A structure represented by the following formula is a copolymer composed of 85 mol% / methyl acrylate 10 mol% / N-methylol acrylamide 5 mol%.

Fine particles 1:
Silica fine particles (average particle diameter: 40 nm, trade name Seahoster KE-E40 manufactured by Nippon Shokubai Co., Ltd.)
Fine particle 2:
Silica fine particles (average particle diameter 70 nm, product name manufactured by Nippon Shokubai Co., Ltd., Seahoster KE-E70)
Release agent 1:
Epoxy group-containing silicone (GE TOSHIBA Silicone Co., Ltd., trade name TSF4730)
Release agent 2:
Amino group-containing silicone (trade name TSF4700, manufactured by GE Toshiba Silicones Co., Ltd.)
Cross-linking agent:
Oxazoline (trade name EPOCROSS WS-700 manufactured by Nippon Shokubai Co., Ltd.)

Fluorine compound surfactant 1:
Perfluorononenyl polyoxyethylene (Foogent 250 manufactured by Neos)
However, the number of repeating units of oxyethylene is 22
Fluorine compound surfactant 2:
N-polyoxyethylene-N-propyl perfluoronormal octanesulfonamide (Femtop EF-122A manufactured by Gemco)
Surfactant:
Polyoxyethylene (n = 7) lauryl ether (trade name NAROACTY N-70, manufactured by Sanyo Chemical Co., Ltd.)

Copolyester:
Copolymerized polyester (Tg = 40 ° C.) with acid component 50 mol% terephthalic acid / 45 mol% isophthalic acid / 5 mol% 5-sodium sulfoisophthalic acid, glycol component 90 mol% ethylene glycol 10 mol% diethylene glycol . This polyester was produced as follows according to the method described in Example 1 of JP-A No. 06-116487. That is, 30 parts of dimethyl terephthalate, 27 parts of dimethyl isophthalate, 5 parts of dimethyl 5-sodiumsulfoisophthalate, 36 parts of ethylene glycol and 3 parts of diethylene glycol were charged into the reactor, and 0.05 part of tetrabutoxy titanium was added thereto. Then, the temperature was controlled at 230 ° C. in a nitrogen atmosphere, and the produced methanol was distilled off to conduct a transesterification reaction. Subsequently, the temperature of the reaction system was gradually raised to 255 ° C., and the inside of the system was reduced to 1 mmHg to carry out a polycondensation reaction to obtain a copolyester.

  The polyester film for in-mold transfer of the present invention can be suitably used as a base film for an in-mold transfer foil.

Claims (2)

It consists of a polyester film and an antistatic layer provided on one side thereof, and the antistatic layer contains a cationic polymer having a unit represented by the following formula (1) as an antistatic agent,

Further containing a silicone compound and a surfactant, the silicone compound is a silicone compound having a reactive group, and the reactive group includes an organic group containing an amino group, an organic group containing an epoxy group, an organic group containing a carboxylic acid group, An organic group selected from a silanol group or an organic group that generates a silanol group by hydrolysis, the surfactant is a fluorine compound having a branched structure, and the antistatic layer is formed by applying an aqueous coating liquid onto a film. A polyester film for in-mold transfer.   The polyester film for in-mold transfer according to claim 1, further comprising an easy adhesion layer on the opposite side of the antistatic layer.