JP2012011657A - Adhesive releasing polyester film for in-mold transfer material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adhesive releasing polyester film for in-mold transfer materials which can easily process a hard coat layer as an adhesive releasing layer on the adhesive releasing layer when providing the adhesive releasing layer on at least one surface of a film used for a substrate of an in-mold transfer foil, is easily peelable from the hard coat layer after transferring, has adhesive releasing properties such that a foil run-off phenomenon does not occur when slit-processing at a width matching to the dimension of a material to be transferred, and is useful as the substrate film of the in-mold transfer foil.SOLUTION: There is provided the adhesive releasing polyester film for the in-mold transfer materials which has the adhesive releasing layer on at least one surface of a polyester film, and in which the adhesive releasing layer contains a copolymer including a specific fluoroalkyl acrylate and acrylate containing no fluorine as constituents and a crosslinking agent, a glass transition point of the copolymer is ≤20°C, and a peel strength of the hard coat layer to the adhesive releasing layer is ≥0.2 N/mm but ≤0.4 N/mm.

Description

  The present invention relates to an adhesive release film for an in-mold transfer material, and more particularly to an adhesive release film for an in-mold transfer material useful as a base film for a transfer foil for in-mold transfer that is transferred and printed simultaneously with molding in injection molding or the like.

Conventionally, as a transfer foil for in-mold, a polyester film is used as a base film, a release layer is provided thereon, a hard coat layer and a printing layer are applied on the release layer, and these are sequentially laminated. ing.
Such in-mold transfer foil is peeled off and separated between the release layer surface and the hard coat layer surface after molding and transfer. That is, after the molding transfer, the printed layer adheres to the surface of the molded product and is taken out as a product, and the hard coat layer becomes the outermost surface of the product. The release layer is removed from the product in a state of being provided on the base film of the transfer foil. Further, as a film suitable for an in-mold transfer foil, it has been studied to provide an adhesive layer between both layers in order to increase the adhesive force between the release layer and the base film.

In recent years, high productivity is required for processing using an in-mold transfer method, and attempts have been made to improve the molding speed. On the other hand, when handling the in-mold transfer foil, sticking of the transfer foils due to electrification and adhesion of dust and dust to the transfer foil surface may occur, thereby reducing productivity. For example, in Patent Document 1, a polyester film for a transfer material having an antistatic layer has been studied for such a problem.
Also, in Patent Document 2, it has excellent antistatic properties from the process of creating a transfer foil for in-mold to molding transfer, and there is no sticking between the transfer foils, and the release layer and the base film are peeled off during transfer. As a film for an in-mold transfer foil without a film, a film having an easy-adhesion layer on one side of a polyester film and an antistatic layer containing a release component on the other side is disclosed. In Patent Document 2, an attempt is made to make such a release component have good compatibility with an antistatic agent and that the release component does not cause printing repelling on the opposite printing surface.

On the other hand, when focusing on the release layer, the conventional release layer is formed by the shock that the slit blade hits when the layers are stacked and then cut (slit) to an appropriate width according to the size of the transfer object. In some cases, the transfer portion such as the hard coat layer and the print layer peeled off from the surface of the release layer at the slit portion. This is due to the fact that the delamination force between the release layer and the hard coat layer is very low, and not only the part that is subjected to transfer but also the part that is not subjected to transfer is excellent in peelability. Is.
Such a foil spill phenomenon is more prominent as the transfer layer is thicker, such as when the release layer has to be thick like a hard coat layer, or when there are many functional layers. Therefore, in order to prevent foil spilling at the time of slitting, when a release layer is provided on the base film, a release layer is provided on a belt-like pattern excluding a portion that hits the slit, and a hard coat layer, a printing layer, and an adhesive are formed thereon. A transfer layer comprising a layer or the like has been studied (Patent Document 3). However, such a method has a problem that a coating pattern suitable for the transfer object must be obtained.

  Patent Document 4 proposes a polyester film having a release layer with a normal peel strength of 2000 mN / cm or less on one side, as a transfer material film, instead of a conventional thermosetting release layer. It is described that a fluorine-containing resin is preferable as one of the components constituting the mold layer. However, in Patent Document 4, although a releasable film that is easily peeled is studied, nothing has been studied on foil spillage.

  Thus, the present situation is that there is a demand for a polyester film for an in-mold transfer material that does not cause foil spillage even without pattern coating and that has releasability after transfer.

JP 2004-223800 A JP 2006-187951 A Japanese Patent Laid-Open No. 11-58584 Japanese Patent Laid-Open No. 2007-111964

  The object of the present invention is to eliminate such problems of the prior art, and to provide a hard coat layer as an adhesive release layer when providing an adhesive release layer on at least one surface of a film used as a base material for an in-mold transfer foil. Adhesive release property that can be easily processed on the release layer and easily peeled off from the hard coat layer after transfer, and that does not cause foil spillage when slitting to a width that matches the size of the transfer object And providing an adhesive release polyester film for an in-mold transfer material that is useful as a base film for an in-mold transfer foil.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that a conventional release layer is a layer having a high releasability focusing only on releasability, and is specific to at least one surface of the polyester film. By providing a coating layer containing an adhesive release component and a crosslinking agent, an adhesive release layer having both functions of an adhesive force and a release force is newly obtained, and has excellent hard coat processability and peelability. Moreover, the inventors have found that the foil spilling phenomenon is suppressed when cutting (slit) with an appropriate width, and have completed the present invention.

  That is, an object of the present invention is to have a pressure-sensitive adhesive release layer on at least one side of a polyester film, and the pressure-sensitive adhesive release layer comprises a fluoroalkyl acrylate represented by the following general formula (I) and an acrylate not containing fluorine as constituent components. Containing a copolymer and a crosslinking agent

(In formula (I), R ₁ represents hydrogen or a methyl group, Rf represents a fluoroalkyl group having 3 to 7 fluorine atoms, and R _X represents a hydrocarbon group having 1 to 5 carbon atoms)
The copolymer has a glass transition temperature of 20 ° C. or less, and the release force of the hard coat layer to the adhesive release layer is from 0.2 N / mm to 0.4 N / mm. Achieved by mold polyester film.

  In addition, the pressure-sensitive adhesive release polyester film for in-mold transfer material of the present invention has, as a preferred embodiment, such a fluoroalkyl acrylate component based on the total molar amount of the copolymer is 5 mol% or more and 90 mol% or less. The surface free energy of the adhesive release layer is 30 mN / m or more and 60 mN / m or less, the adhesive release layer is provided directly on at least one surface of the polyester film, and the adhesive release layer is a polyester film. Including those having at least one of the following: forming by coating within the film forming step, and further having an antistatic release layer on the side opposite to the adhesive release layer of the polyester film To do.

  The polyester film of the present invention has excellent hard coat processability and releasability, and when it is cut (slit) with an appropriate width, the foil spill phenomenon is suppressed. Since it is not necessary to form a mold layer with a coating pattern suitable for an object to be transferred and a release layer can be coated on the entire surface of the transfer foil, it can be suitably used as a film for an in-mold transfer material.

Hereinafter, the present invention will be described in detail.
[Polyester film]
The polyester constituting the polyester film of the present invention 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 the polyester include polyethylene terephthalate, polyethylene isophthalate, polybutylene terephthalate, poly (1,4-cyclohexylenedimethylene terephthalate), and polyethylene-2,6-naphthalenedicarboxylate.

  The polyester may be a homopolymer, a copolymer having one of these polyesters as a main component, or a blend. Here, the “main component” is 80 mol% or more based on the number of moles of the repeating structural unit of the polyester. The ratio of the main component is preferably 85 mol% or more, and more preferably 90 mol% or more. The copolymer component or blend component is 20 mol% or less, preferably 15 mol% or less, more preferably 10 mol% or less, based on the number of moles of the repeating structural unit of the polyester. As the polyester, polyethylene terephthalate is particularly preferable because of a good balance between mechanical properties and moldability.

  The polyester film of the present invention may contain lubricant particles, a colorant, an antistatic agent, and an antioxidant within the range not impairing the problems of the present invention. When high transparency and surface flatness are required, it is preferable that lubricant particles are not substantially contained.

  The polyester film can be produced, for example, by the following method. That is, polyester is melt-extruded into a film shape, cooled and solidified with a casting drum to form an amorphous unstretched film, and the longitudinal direction (hereinafter sometimes referred to as a continuous film-forming direction, the longitudinal direction, and the MD direction) and the lateral direction (hereinafter referred to as the “non-stretched film”). , Sometimes referred to as the width direction and the TD direction). Stretching in the machine direction is, for example, at a temperature of 60 to 130 ° C., preferably 90 to 125 ° C., and stretched in the machine direction of, for example, 2.0 to 4.0 times, preferably 2.5 to 3.5 times. The stretching in the transverse direction is, for example, at a temperature of 60 to 130 ° C., preferably 90 to 125 ° C., and is stretched in the transverse direction, for example, 2.0 to 4.5 times, preferably 3.0 to 4.2 times. The area magnification after biaxial stretching is preferably 13 or less.

  In addition, it is preferable to perform a heat setting process after extending | stretching a film. The heat setting treatment is preferably performed within a period of 1 to 30 seconds at a temperature higher than the final stretching temperature and not higher than the melting point. For example, in the case of a polyethylene terephthalate film, it is preferable to select and heat-set at a temperature of 150 to 250 ° C. and a time of 2 to 30 seconds. At that time, it is performed under a limited shrinkage or elongation within 20%, or under a constant length, or may be performed in two or more stages.

  The center line surface roughness of the surface of the polyester film is preferably 1 to 50 nm. By setting the center line surface roughness of the surface of the polyester film within this range, an in-mold transfer film having a center line average surface roughness of 1 to 40 nm on the surface of the coating layer can be obtained.

  When used as an in-mold transfer material, the thickness of the polyester film is preferably 12 to 100 μm, more preferably 25 to 75 μm from the viewpoints of handling properties and moldability, and if necessary, from the viewpoint of transparency.

[Adhesive release layer]
The film of the present invention is a copolymer of a fluoroalkyl acrylate represented by the following general formula (I) and an acrylate not containing fluorine (hereinafter referred to as a fluorinated acrylic copolymer) on at least one surface of a polyester film. And an adhesive release layer containing a crosslinking agent, and the glass transition temperature of the copolymer is 20 ° C. or lower.

(In formula (I), R ₁ represents hydrogen or a methyl group, Rf represents a fluoroalkyl group having 3 to 7 fluorine atoms, and R _X represents a hydrocarbon group having 1 to 5 carbon atoms)
Moreover, the peeling force of the hard-coat layer with respect to this adhesion release layer is 0.2 N / mm or more and 0.4 N / mm or less. The film of the present invention is characterized in that it has an adhesive release layer having both functions of an adhesive force and a release force. Specifically, the adhesive release layer contains a fluorinated acrylic copolymer. In addition, it provides release performance by suppressing cohesive failure of the adhesive release layer with a crosslinking agent, and also has adhesive performance due to the low glass transition temperature of the fluorinated acrylic copolymer. An adhesive release layer having both functions of an adhesive force and a release force can be obtained in which the peeling force of the coat layer is 0.2 N / mm or more and 0.4 N / mm or less.

  And when an adhesive release polyester film having such an adhesive release layer is used for in-mold transfer foil applications, a hard coat agent can be applied on the adhesive release layer, and after the transfer, the hard coat layer is peeled off In addition, in slit processing, generation of foil spillage, debris and dust due to peeling of the adhesive release layer and the hard coat layer can be suppressed.

(Fluoroacrylic copolymer)
The fluorinated acrylic copolymer used for the pressure-sensitive adhesive release layer of the present invention is a copolymer comprising a fluoroalkyl acrylate represented by the following general formula (I) and an acrylate not containing fluorine as constituent components.

(In formula (I), R ₁ represents hydrogen or a methyl group, Rf represents a fluoroalkyl group having 3 to 7 fluorine atoms, and R _X represents a hydrocarbon group having 1 to 5 carbon atoms)
Here, the fluoroalkyl acrylate includes fluoroalkyl metallate, and the acrylate not containing fluorine refers to a generic name of alkyl (meth) acrylate containing no fluorine.
When the fluorinated acrylic copolymer contains a fluoroalkyl group and the number of fluorine atoms is 3 or more, release performance is exhibited. Further, when the number of fluorine atoms in the fluoroalkyl group is 7 or less, the dispersibility in water is improved, so that it can be easily emulsified and the release force can be prevented from becoming too high. The number of fluorine atoms in such a fluoroalkyl group is preferably 3-5.

In the formula (I), R _X is a hydrocarbon group having 1 to 5 carbon atoms, specifically, a saturated chain hydrocarbon group such as a methylene group, an ethylene group, a propylene group, a butylene group, or a pentylene group. And saturated alicyclic hydrocarbon groups such as cyclopentylene group are exemplified, and ethylene group is particularly preferable.

  Specific examples of the fluoroalkyl acrylate represented by the general formula (I) constituting the copolymer component of the fluorinated acrylic copolymer include trifluoroethyl (meth) acrylate, trifluoropropyl (meth) acrylate, and tetrafluoropropyl. Examples of the copolymer component include (meth) acrylate, trifluorobutyl (meth) acrylate, and hexafluorobutyl (meth) acrylate as monomer components. Such a component is preferably soluble or dispersible in water, but is also preferably soluble in water containing some organic solvent, and particularly preferably the monomer component is trifluoroethyl (meth) acrylate or trifluorobutyl (meta). ) By being an acrylate, the adhesiveness with the polyester film, the releasability with the hard coat layer, and the workability are improved.

Examples of the monomer constituting the other copolymerization component of the fluorinated acrylic copolymer include acrylates that do not contain fluorine, and alkyl acrylates having 1 to 18 carbon atoms in the alkyl group or those having 1 to 18 carbon atoms in the alkyl group. Exemplified is at least one alkyl methacrylate that is 18.
Examples of the alkyl acrylate having an alkyl group having 1 to 18 carbon atoms include methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, isobutyl acrylate, n-amyl acrylate, isoamyl acrylate, acrylic Examples include acid hexyl, cyclohexyl acrylate, 2-ethylhexyl acrylate, and lauryl acrylate. Of these, alkyl acrylates having 4 to 12 carbon atoms in the alkyl group are preferable, and n-butyl acrylate and 2-ethylhexyl acrylate are particularly preferable. These monomer components may be used alone or in admixture of two or more.

  Examples of the alkyl methacrylate having 1 to 18 carbon atoms in the alkyl group include methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-amyl methacrylate, and isoamyl methacrylate. Hexyl methacrylate, cyclohexyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate and the like. Of these, alkyl methacrylates having 1 to 6 carbon atoms in the alkyl group are preferable, and methyl methacrylate is particularly preferable.

  The fluorinated acrylic copolymer of the present invention is a copolymer comprising the fluoroalkyl acrylate represented by the general formula (I) and an acrylate not containing fluorine as constituent components, and is based on the total molar amount of the copolymer. As such, it is preferable that this fluoroalkyl acrylate component is 5 mol% or more and 90 mol% or less, More preferably, it is 10 mol% or more and 70 mol% or less, Especially preferably, they are 20 mol% or more and 50 mol% or less. If the fluoroalkyl acrylate component is less than the lower limit, sufficient release performance may not be exhibited. On the other hand, when the fluoroalkyl acrylate component exceeds the upper limit, the film forming property may be poor.

  The fluorinated acrylic copolymer of the present invention can be produced by emulsion polymerization. A known redox initiator can be used as the polymerization initiator, and examples thereof include hydrogen peroxide, ammonium persulfate, potassium persulfate, and t-butyl hydroperoxide.

  The emulsion polymerization reaction can be carried out at a temperature and reaction time depending on the type of monomer and radical polymerization initiator used and other conditions. As the polymerization conditions, for example, the polymerization reaction temperature can be 50 to 90 ° C., and the polymerization reaction time can be 3 to 24 hours. Emulsion polymerization can also be performed in inert gas atmosphere, such as nitrogen gas or argon gas, for example.

  These fluorinated acrylic copolymers may be in the form of an emulsion. Or a powder form may be sufficient. Examples of the method of making the fluorinated acrylic copolymer into a powder form include a method of drying the fluorinated acrylic copolymer prepared by the above method. On the other hand, the emulsion form is preferred from the viewpoint that the coating layer can be prepared easily and in a large area.

  The glass transition temperature of the fluorinated acrylic copolymer of the present invention is 20 ° C. or less, more preferably 10 ° C. or less, still more preferably 0 ° C. or less, and particularly preferably −10 ° C. or less. When using a fluorinated acrylic copolymer with a glass transition temperature higher than the upper limit, the adhesive strength at room temperature is low, and the peel strength from the hard coat layer is lower than the lower limit. It is difficult to sufficiently suppress foil spills and foil scraps. The glass transition temperature of the fluorinated acrylic copolymer is preferably lower within this range, but the lower limit is limited to −40 ° C. due to the nature of the polymer. The glass transition temperature of the fluorinated acrylic copolymer can be adjusted by selecting the acrylic monomer species and controlling the blending amount.

  Moreover, the weight average molecular weight of the fluorinated acrylic copolymer used in the present invention is preferably in the range of 500 to 120,000, more preferably in the range of 2,000 to 40,000. By using a fluorinated acrylic copolymer having a weight average molecular weight in such a range, excellent film-forming properties, durability, antifouling properties, chemical resistance and adhesion to a substrate can be obtained.

  The fluorinated acrylic copolymer of the present invention preferably forms a spherical dispersed phase in the coating liquid, and the average particle size of the dispersed phase is preferably 0.02 to 1.0 μm, more preferably 0.05 to 0.5 μm, most preferably 0.03 to 0.2 μm. If it is this range, peelability, workability, film-forming property, durability, antifouling property and adhesion to a substrate can be obtained.

  The content of the fluorinated acrylic copolymer is preferably 50% by weight or more and 95% by weight or less based on the weight of the pressure-sensitive adhesive release layer. Further, the upper limit of the addition amount of the fluorinated acrylic copolymer is more preferably 90% by weight, further preferably 85% by weight, and particularly preferably 80% by weight. Further, the lower limit of the addition amount of the fluorinated acrylic copolymer is more preferably 55% by weight, further preferably 60% by weight, and particularly preferably 65% by weight. If the content of the fluorinated acrylic copolymer is less than the lower limit, the adhesion with the polyester film, the adhesive release performance may not be sufficiently expressed, as a result of the relatively increased content of the crosslinking agent, The film-forming property of the pressure-sensitive adhesive release layer may be deteriorated and the coating appearance may be deteriorated. On the other hand, if the content of the fluorinated acrylic copolymer exceeds the upper limit value, the content of the crosslinking agent is relatively reduced, so the cohesive force of the adhesive release layer is lowered, and the release performance is not sufficiently exhibited. There is.

(Crosslinking agent)
Moreover, it is necessary to add a crosslinking agent to the adhesive release layer of the present invention in order to improve the cohesive strength of the layer. When the crosslinking agent is not added, the cohesive force of the adhesive release layer is not sufficient, and even if the fluorinated acrylic copolymer of the present invention is contained, the cohesive failure occurs first, and the fluorinated acrylic copolymer The mold release performance by the polymer is not sufficiently developed.

  As a crosslinking agent, an epoxy compound, an oxazoline compound, a melamine compound, an isocyanate compound can be illustrated, and the compound generally called a coupling agent can also be used. It is preferable to use an epoxy compound or an oxazoline compound because of easy handling and the pot life of the coating liquid, and it is also preferable to use a coupling agent.

Examples of the epoxy compound include polyepoxy compounds, diepoxy compounds, monoepoxy compounds, and the like, and more specifically, glycidyl ether compounds and glycidyl amine compounds thereof are exemplified.
As the oxazoline compound, a polymer containing an oxazoline group is preferable. Specifically, it can be prepared by polymerization of an addition polymerizable oxazoline group-containing monomer alone or with another monomer. Addition polymerizable oxazoline group-containing monomers include 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, 2-vinyl-5-methyl-2-oxazoline, 2-isopropenyl-2-oxazoline, 2-isopropenyl-4-methyl-2-oxazoline, 2-isopropenyl-5-ethyl-2-oxazoline, and the like can be mentioned, and one or a mixture of two or more thereof can be used. Among these, 2-isopropenyl-2-oxazoline is preferred because it is easily available industrially. The other monomer is not particularly limited as long as it is a monomer copolymerizable with an addition polymerizable oxazoline group-containing monomer.

  The melamine compound is preferably a compound obtained by reacting a methylol melamine derivative obtained by condensing melamine and formaldehyde with 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- 4,4 'diisocyanate, 3,3' dimethyldiphenylmethane-4,4'-diisocyanate, metaphenylene diisocyanate and the like.

  The content of the crosslinking agent is preferably 5% by weight or more and 50% by weight or less based on the weight of the pressure-sensitive adhesive release layer. Further, the upper limit of the addition amount of the crosslinking agent is more preferably 40% by weight, further preferably 30% by weight, and particularly preferably 20% by weight. If the content of the crosslinking agent is less than the lower limit, the cohesive force of the pressure-sensitive adhesive release layer is lowered, and the release performance may not be sufficiently exhibited. On the other hand, when the content of the crosslinking agent exceeds the upper limit value, the film forming property of the pressure-sensitive adhesive release layer is deteriorated, and the coating appearance may be deteriorated.

(Surfactant)
The fluorinated acrylic copolymer constituting the pressure-sensitive adhesive release layer of the present invention is preferably used in the form of an aqueous dispersion or an emulsion from the viewpoint of ease of handling during coating and working environment. In order to obtain a good aqueous dispersion and emulsion form, the use of a surfactant is preferred, and a nonionic surfactant is particularly preferred because of its dispersion stability with other components of the coating liquid. The content of the surfactant is preferably in the range of 1% by weight to 15% by weight, more preferably in the range of 5% by weight to 12% by weight, based on the weight of the adhesive release layer.

[Peeling force]
When the pressure-sensitive adhesive release layer of the present invention contains the fluorinated acrylic copolymer and also contains a crosslinking agent, the peeling force of the hard coat layer with respect to the pressure-sensitive adhesive release layer of the film of the present invention is 0.2 N / It has a peeling force in the range of not less than mm and not more than 0.4 N / mm. The peeling force is preferably 0.25 N / mm or more and 0.35 N / mm or less, more preferably 0.30 N / mm or more and 0.35 N / mm. Here, the peeling force in the present invention is a hard coating containing 100 parts by weight of a hard coating agent (product name “5LC114H”) manufactured by DIC Graphics Co., Ltd. and 3 parts by weight of a hardener for the hard coating agent on the adhesive release layer. It is represented by a value obtained by measuring the peeling force after applying the coating composition, drying it with hot air at 150 ° C. for 1 minute and incompletely curing it with heat.

  When the adhesive release layer of the film used for in-mold transfer satisfies the above-mentioned peeling force with respect to the peeling force with the hard coat layer, the hard coat coating agent is used when creating the in-mold transfer foil. It can be applied on the adhesive release layer without causing coating omission, and it has excellent adhesion to the hard coat layer, so an unnecessary hard coat is required when slitting the in-mold transfer foil to match the size of the molded product. The foil spilling phenomenon that the layer portion is peeled can be suppressed, and the transfer foil after the in-mold transfer has excellent peelability.

  When the peeling force is less than the lower limit value, foil spillage during slit processing occurs due to poor adhesion. Moreover, in the coating layer composition in which the peeling force is less than the lower limit, as a result, coating omission is likely to occur when the hard coat coating agent is coated on the adhesive release layer. On the other hand, when the peeling force exceeds the upper limit value, the releasability is poor and it is difficult to remove the transfer foil after in-mold transfer.

[Surface free energy]
The surface free energy of the pressure-sensitive adhesive release layer of the present invention is preferably 15 mN / m or more and 60 mN / m or less. The surface free energy of the pressure-sensitive adhesive release layer is more preferably a lower limit value of 25 mN / m, more preferably 30 mN / m, and an upper limit value of 50 mN / m, further preferably 45 mN. / M.

  When the surface free energy of the pressure-sensitive adhesive release layer is larger than the upper limit value, the coatability of the hard coat agent is improved, but the adhesive force becomes too high, and the hard coat layer may be inferior in the mold release property. Also, if the surface free energy of the pressure-sensitive adhesive release layer is less than the lower limit, the coatability may be deteriorated, and the releasability is too good to obtain the peeling force required in the present invention.

Such surface free energy in the present invention is represented by the surface free energy γ _S (hereinafter sometimes referred to as surface tension) defined by the Fowkes expansion formula represented by the following formula (1).
^{_{γ S = γ S d + γ}} S p + γ S h ··· (1)
(Represented in the above formula, gamma _S ^d is the dispersion component, gamma _S ^p is the polar component, gamma _S ^h is a hydrogen bonding component, respectively)
The Fowkes expansion formula includes a dispersion component γ _S ^d derived from London force, a polar component γ _S ^p derived from Debye force (permanent dipole moment, charge transfer), and a hydrogen bond component γ _S ^h derived from hydrogen bond force. In terms of attention, the correlation between the surface forming composition and the surface free energy is high, and further, the correlation with the peeling force is high. Conventionally, the release force of the release layer has often been examined by the surface tension according to the Fowkes formula, but the Fowkes formula only considers the dispersion force as an interaction. The present invention has found that the Fowkes formula has a low correlation between the surface forming composition and the peel force, and has been devised by Kitasaki, Hata et al. (Japan Adhesion Association paper) instead of the surface tension by the conventional Fowkes formula. 8 (3), 131-141 (1972)) The surface free energy obtained by the extended Fowkes equation is used, and the surface release is obtained by adding the fluorinated acrylic copolymer of the present invention to the adhesive release layer. You can get energy.

The dispersion force component γ _S ^d constituting the surface free energy γ _S is preferably in the range of more than 0 mN / m and not more than 30 mN / m. The polarity of the component or dipole component _gamma ^{S p} less than 20 mN / m exceeded 0 mN / m, the hydrogen bond component _gamma ^{S h} is preferably not more than 2 mN / m exceeded 0 mN / m.

[Solvent resistance]
The pressure-sensitive adhesive release layer of the present invention is excellent in solvent resistance against methyl ethyl ketone solvent by containing the above-mentioned fluorinated acrylic copolymer. Due to its excellent solvent resistance to methyl ethyl ketone solvent, it prevents the abrasion failure caused by solvent when a hard coat layer containing methyl ethyl ketone as a solvent is formed on the adhesive release layer, so the interface between the adhesive release layer and the hard coat layer Thus, it is possible to suppress the problem that the adhesive release layer is not cohesively broken and the hard coat layer cannot be peeled off.

[Antistatic release layer]
In the pressure-sensitive adhesive release polyester film of the present invention, it is preferable to further provide an antistatic release layer on the surface of the polyester film opposite to the pressure-sensitive adhesive release layer. Such an antistatic release layer is preferably an antistatic release coating layer provided by coating, and preferably contains an antistatic agent and a release agent. The antistatic release layer is a layer generally provided in a film for transfer material for in-mold, and is often imparted not only with chargeability but also with release properties in order to suppress sticking between transfer foils due to charging. However, a hard coat layer is not provided on such a layer, and the function required in addition to the antistatic property is usually only a release force necessary for preventing sticking between films, and an adhesive force is not required. It is a functional layer different from the pressure-sensitive adhesive release layer of the present invention.
By having such a layer, when handling the transfer foil for in-mold, it is possible to suppress sticking of the transfer foils due to electrification and adhesion of dust and dust to the transfer foil surface.

[Coating method]
In the present invention, the pressure-sensitive adhesive release layer is preferably provided on at least one surface of the polyester film, and is preferably provided on one surface. As a method for providing the pressure-sensitive adhesive release layer on the polyester film, it is preferably formed by applying the polyester film in a film forming process (sometimes referred to as in-line).
Conventionally, an easy-adhesion layer was formed on a polyester film, and after such a film was once rolled, a method of providing a release layer on the easy-adhesion layer as a base of a hard coat layer in a separate process was used. On the other hand, the feature of this method is that the pressure-sensitive adhesive release layer having the peeling force of the present invention can be directly coated on the polyester film in the process of forming the polyester film, and the process can be simplified. . Moreover, since it will dry and heat-process in a horizontal extending process, it is preferable if it apply | coats after the longitudinal stretch in the polyester film manufacturing process by a normal biaxial stretching method.

  The method of laminating the pressure-sensitive adhesive release layer on the polyester film by coating is not particularly limited, and for example, a coating method as shown in Yuji Harasaki, Tsuji Shoten, 1979, “Coating Method” can be used. Specifically, air doctor coater, blade coater, rod coater, knife coater, squeeze coater, impregnated coater, reverse roll coater, transfer roll coater, gravure coater, kiss roll coater, cast coater, spray coater, curtain coater, calendar Examples of the method include a coater, an extrusion coater, and a bar coater.

The coating amount of the coating solution is usually 4 to 30 g / m ² , preferably 5 to 20 g / m ² , and more preferably 6 to 10 g / m ² . Moreover, the thickness of the obtained adhesive release layer is preferably 0.01 to 0.2 μm, more preferably 0.01 to 0.08 μm as the thickness after drying. When the thickness of the adhesive release layer is less than the lower limit, the releasability may be insufficient, and when the upper limit is exceeded, the in-mold transfer foil polyester film further has an antistatic release layer. It may be easy to cause blocking with the antistatic release layer.

In the present invention, when the antistatic release layer is further provided, the antistatic layer is preferably provided on the surface of the polyester film opposite to the adhesive release layer. The antistatic layer is preferably provided by coating. As a coating method, the same method as that for the pressure-sensitive adhesive release layer can be used.
The thickness of the antistatic layer is preferably 0.01 to 0.2 [mu] m, more preferably 0.01 to 0.08 [mu] m, as the thickness after drying. When the thickness of the antistatic layer is less than the lower limit, the antistatic property may be insufficient, and when the thickness exceeds the upper limit, blocking with the in-mold transfer foil may easily occur.

[Film for in-mold transfer foil]
The pressure-sensitive adhesive release polyester film of the present invention has an in-mold transfer by having, as a pressure-sensitive adhesive release layer, a coating layer containing a specific fluorinated acrylic copolymer and a crosslinking agent on at least one surface of the polyester film. When used as a film for materials, it has excellent adhesive release properties and processability from the in-mold transfer foil production process to the molding transfer, application of hard coat agent and peeling of the hard coat, Furthermore, foil spilling, generation of dust and foil dust at the time of slit processing, and adhesion of the generated dust and foil dust to the product surface can be suppressed, and productivity can be significantly improved.

  Moreover, conventionally, after laminating an easy-adhesion layer on a polyester film in a film production process, it was a process of laminating a release layer in which a release agent having an organic solvent composition was applied on the easy-adhesion layer in a separate process. However, the pressure-sensitive adhesive release layer of the present invention also has the effects of simplifying the process, reducing the environment, and reducing the cost.

  When the film for in-mold transfer material of the present invention has a releasable coating layer further containing an antistatic component on the surface opposite to the adhesive release layer, it is used as a film for in-mold transfer material. In addition, it has excellent antistatic properties and releasability from the process of creating a transfer foil for in-mold to molding and transfer. Sticking between transfer foils by charging and blocking, and dust and dirt on the surface of the transfer foil Etc. can be suppressed, and productivity can be remarkably improved.

Hereinafter, the present invention will be described in more detail with reference to examples. Various physical properties were evaluated by the following methods. Moreover, wt% represents weight%, and part represents weight part.
(1) Glass transition temperature measurement Using a differential scanning calorimeter (DSC SSC5200, manufactured by Seiko Instruments Inc.), the dried product of the coating solution for the adhesive release layer was used as a sample, and a sample amount of 5 mg was measured. It was sealed in an aluminum pan, and the temperature was raised from 25 ° C. to 300 ° C. under a temperature rising condition of 20 ° C./min in a nitrogen atmosphere, and DSC measurement was performed to measure the glass transition temperature of the fluorinated acrylic copolymer.

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

(3) Measurement of peel strength of hard coat layer on adhesive release layer The thickness of the hard coat agent coating liquid containing the thermosetting hard coat agent shown below on the surface of the adhesive release layer of the polyester film is as follows. It apply | coated so that it might become 10 micrometers, and it dried in 150 degreeC and the hot air oven for 1 minute, and produced the hard-coat layer.
An adhesive tape having a width of 18 mm (trade name “No. 405-1P” manufactured by Nichiban Co., Ltd.) was bonded to the surface of the prepared hard coat layer, and then pressure-bonded with a metal roller (linear pressure 2 kg / cm). After leaving at room temperature for 30 minutes, the adhesive tape was peeled off together with the hard coat layer, and the peeling force at that time was measured. The measurement was performed using a tensile tester under the condition of 90 ° peeling under the condition of a tensile speed of 300 mm / min. Evaluation was performed at n = 5, and the average value was obtained as the hard coat layer peeling force.

(Hard coating agent coating solution)
Prepare 100 parts by weight of a hard coat agent (product name “5LC114H”) manufactured by DIC Graphics Co., Ltd. as a hard coat agent and 3 parts by weight of a curing agent for the hard coat agent, and use MEK (methyl ethyl ketone) as a solvent as a non-volatile component. A 30% hard coating agent coating solution was prepared.

(4) Contact angle and surface free energy Automatic contact angle measuring device (manufactured by Kyowa Interface Chemical Co., Ltd.) for the adhesive release layer surface of a film sample conditioned for 24 hours under conditions of 23 ° C. and 65% RH Were used to measure static contact angles with water, methylene iodide, and n-hexadecane. Each liquid sample is measured five times, and the average value is taken as the contact angle of the film sample. Using the surface tension and surface tension component values (Table 1) of each liquid sample, the Fowkes of the following formula (I) The surface free energy of the adhesive release layer surface was calculated from the expansion formula.
^{_{γ S = γ S d + γ}} S p + γ S h ··· (1)
(Represented in the above formula, gamma _S ^d is the dispersion component, gamma _S ^p is the polar component, gamma _S ^h is a hydrogen bonding component, respectively)

(5) Foil spillability at the time of peeling off the hard coat In the hard coat layer peeling force measurement test of the adhesive release layer, when the hard coat layer was peeled off with the adhesive tape, it was pulled by the adhesive tape, and the hard coat was peeled off excessively. The presence or absence of occurrence of foil spillage in the layer was observed and evaluated.
○: Hard coat layer peels off at the same width as the adhesive tape width △: Hard coat layer peels partially wider than the adhesive tape width ×: Overall hard coat layer peels wider than the tape width

(6) Solvent rubbing test According to the coating film deterioration evaluation of JIS-K5600-8, methyl ethyl ketone was soaked in gauze, gauze was placed on the adhesive release layer, and a total load of 150 g (150 g of jig weight, additional load) 0 g) load was applied to the surface of the coating layer while reciprocating one load, and then the coating width and scratches of the coating layer observed on the surface were observed. Was evaluated. Evaluation was observed in the range of 2 cm × 10 cm among the parts subjected to the solvent rubbing test.
○: No peeling, little scratches ... Good solvent resistance △: Little peeling, scratches ··· Somewhat good solvent resistance ×: Some peeling, scratches ··· Solvent resistance Bad

(7) Haze of adhesive release layer
According to JIS K7136, the haze of the adhesive release layer was measured from the following formula (2) using a Nippon Denshoku Industries Co., Ltd. haze measuring device (NDH-2000). In the formula, the film haze is the haze value of the whole film in which the adhesive release layer is formed on the polyester film, and the adhesive release layer uncoated film haze is not applied with the adhesive release layer. It refers to the film haze in the state.
Antistatic release layer haze = film haze-adhesive release layer uncoated film haze (2)
A +: Less than 0.1% A: 0.1% or more and less than 0.4% B: 0.4% or more and less than 0.8% C: 0.8% or more In this evaluation, up to A satisfies practical performance. .

[Example 1]
Molten polyethylene terephthalate ([η] = 0.64 dl / g, Tg = 78 ° C.) containing 0.01 wt% of silicon oxide 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, an adhesive release layer coating solution (2 wt% coating solution) comprising the coating layer constituents shown in Table 2 was applied to the surface of the film at 6 g / m ^2. (The coating layer thickness after drying is 0.04 μm), the antistatic layer coating solution (1.6 wt% coating solution) is 8 g / m ² (the coating layer thickness after drying is 0.04 μm) on the back surface of the film, Each was uniformly applied with a roll coater.
Next, this coated film was subsequently dried at 105 ° C., stretched 3.5 times in the transverse direction at 140 ° C., heat-fixed at 220 ° C., and 50 μm biaxially stretched with the coating film shown in Table 1. A polyester film was obtained.

[Examples 2-3, Comparative Examples 1-4]
A laminated polyester film was obtained in the same manner as in Example 1 except that the composition of the coating solution was changed as shown in Table 2.

(Adhesive release layer composition)
Fluoroacrylic copolymer A (trifluorobutyl acrylate-2-ethylhexyl acrylate copolymer; glass transition temperature −20 ° C.):
It is composed of trifluorobutyl acrylate, 2-ethylhexyl acrylate, and alkyl diphenyl ether disulfonate as an emulsifier.
That is, 1050 parts of ion-exchanged water and 22.6 parts of alkyldiphenyl ether disulfonate as an emulsifier were charged in a four-necked flask and heated to 80 ° C. in a nitrogen stream, and then 6.4 parts of ammonium persulfate as a polymerization initiator. Further, 110.0 parts of trifluorobutyl acrylate and 6.9 parts of 2-ethylhexyl acrylate, which are monomers, are added dropwise while adjusting the liquid temperature to 70 to 80 ° C. over 3 hours. Is maintained for 5 hours, and the reaction is continued under stirring, followed by cooling and drying with a vacuum dryer, and an aqueous dispersion of a fluorinated acrylic copolymer having an average particle size of 0.06 μm and a non-volatile component weight of 35% Got. In this fluorinated acrylic copolymer, the monomer component is trifluorobutyl acrylate, the copolymer component is 30 mol% based on the total repeating units of the copolymer, and the monomer component is 2-ethylhexyl acrylate. The polymerization component was 70 mol% based on all repeating units of the copolymer.
-Fluoroacrylic copolymer B:
Fluorinated acrylic emulsion (Nippon Paint Co., Ltd., trade name “FS-701E”, glass transition temperature 80 ° C.)
・ Fluoroacrylic copolymer C:
Fluorine-containing resin emulsion containing 80.0 g of CF ₃ (CF ₂ ) _n CH ₂ CH ₂ OCOCH═CH ₂ (average of n = 9) and 20.0 g of acetoacetoxyethyl methacrylate (glass transition temperature −24 ° C.)
・ Acrylic polymer:
Acrylic emulsion (Toa Gosei Co., Ltd., trade name “Aron A-106”, glass transition temperature 10 ° C.)
・ Crosslinking agent: Oxazoline compound (made by Nippon Shokubai Co., Ltd., trade name “Epocross WS-700”)
Surfactant: Polyoxyethylene (n = 7) lauryl ether (manufactured by Sanyo Chemical Co., Ltd., trade name “Naroacty N-70”)

・架橋剤 ： オキサゾリン化合物（株式会社日本触媒製、商品名「エポクロスＷＳ−７００」）
・界面活性剤 ： ポリオキシエチレン（ｎ＝７）ラウリルエーテル（三洋化成株式会社製 商品名「ナロアクティーＮ−７０」） (Antistatic layer composition)
Silicone component: Epoxy group-containing silicone (trade name TSF4730 manufactured by GE Toshiba Silicone Co., Ltd.)
・ Cationic polymer:
A copolymer having a structure represented by the following formula (II) consisting of 80 mol% / methyl acrylate 15 mol% / N-methylol acrylamide 5 mol% was used.

・ Crosslinking agent: Oxazoline compound (made by Nippon Shokubai Co., Ltd., trade name “Epocross WS-700”)
Surfactant: Polyoxyethylene (n = 7) lauryl ether (trade name “Naroacty N-70” manufactured by Sanyo Chemical Industries, Ltd.)

  The polyester film of the present invention has excellent hard coat processability and releasability, and when it is cut (slit) with an appropriate width, the foil spill phenomenon is suppressed. Since it is not necessary to form a mold layer with a coating pattern suitable for an object to be transferred and a release layer can be coated on the entire surface of the transfer foil, it can be suitably used as a film for an in-mold transfer material.

Claims (6)

A copolymer having a pressure-sensitive adhesive release layer on at least one surface of a polyester film, and the pressure-sensitive adhesive release layer comprises a fluoroalkyl acrylate represented by the following general formula (I) and an acrylate not containing fluorine as a constituent component and a crosslinking agent Containing

(In formula (I), R ₁ represents hydrogen or a methyl group, Rf represents a fluoroalkyl group having 3 to 7 fluorine atoms, and R _X represents a hydrocarbon group having 1 to 5 carbon atoms)
An in-mold characterized in that the glass transition temperature of the copolymer is 20 ° C. or less, and the peeling force of the hard coat layer to the adhesive release layer is 0.2 N / mm or more and 0.4 N / mm or less. Adhesive release polyester film for transfer materials.   The pressure-sensitive adhesive release polyester film for an in-mold transfer material according to claim 1, wherein the fluoroalkyl acrylate component is 5 mol% or more and 90 mol% or less based on the total molar amount of the copolymer.   The pressure-sensitive adhesive release polyester film for an in-mold transfer material according to claim 1, wherein the surface free energy of the pressure-sensitive adhesive release layer is 30 mN / m or more and 60 mN / m or less.   The pressure-sensitive adhesive release polyester film for in-mold transfer material according to any one of claims 1 to 3, wherein the pressure-sensitive adhesive release layer is directly provided on at least one surface of the polyester film.   The pressure-sensitive adhesive release polyester film for in-mold transfer foil according to any one of claims 1 to 4, wherein the pressure-sensitive adhesive release layer is formed by applying in a film forming process of the polyester film.   The pressure-sensitive adhesive release polyester film for an in-mold transfer material according to any one of claims 1 to 5, further comprising an antistatic release layer on the surface opposite to the pressure-sensitive adhesive release layer of the polyester film.