JP2001240819A - Adhesive film for overlamination - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an adhesive film for overlamination having water resistance even when an acrylic emulsion type adhesive is used, scarcely causing a peeling mark in an adhesive layer without deteriorating transparency even when the adhesive film is laminated to an adeherend and gentle to environments without requiring a release sheet. SOLUTION: This adhesive film for overlamination is obtained by laminating a release agent layer/a transparent film/the adhesive layer in the order. In the adhesive film, the release agent layer has rubber elasticity and the adhesive is the acrylic emulsion type adhesive having 70-120 deg. contact angle of the adhesive layer surface with water (measured under an environment at 23 deg.C after the passage of 60 s from dropping water in an amount of 5 μL). The adhesive film for overlamination is prepared by directly coating the transparent film with the acrylic adhesive. The release agent is a silicone-based release agent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adhesive film for overlaminating. More specifically, the present invention relates to an adhesive film for over-laminate which has water resistance, does not impair transparency by floating or bubbles even when the adhesive film for over-laminate is adhered to an adherend, and does not require a release sheet.

[0002]

2. Description of the Related Art Overlaminating adhesive films are used for protecting the printed surface of a printed matter printed by thermal transfer printing, ink jet printing, offset printing, letterpress printing, gravure printing, etc. from water, sunlight and the like. is there. The general structure of the adhesive film for over lamination is
An adhesive is sandwiched between a surface substrate (film) and a release sheet (hereinafter, also referred to as a release liner). The release sheet is peeled off when used.

[0003] The release sheet must be easy to peel off at the interface between the surface layer of the pressure-sensitive adhesive and the surface layer of the release agent on the surface substrate. Kraft paper, glassine paper, woodfree paper, cast paper, clay-coated paper, etc. Polyamide base paper laminated with a resin film such as polyethylene, or kraft paper, high-quality paper, cast paper, etc., with a resin coating provided with a sealing layer mainly composed of a water-soluble polymer such as polyvinyl alcohol or starch and / or a pigment Silicone release agents for base paper, films of polyolefin, polyester, etc. and synthetic paper,
Those coated with a silicone-modified resin-based release agent, a fluorine compound-based release agent, or the like are used.

[0004] The above-mentioned pressure-sensitive adhesive film for over-lamination is usually prepared by applying a pressure-sensitive adhesive to a surface substrate using a coater head of a roll coater type, a comma coater type, a slot die type or the like, and then bonding a release sheet (direct coating). Pressure-sensitive adhesive film is produced by a method of applying a pressure-sensitive adhesive to a release sheet and then bonding a surface substrate thereto (transfer coating method).

However, the above-mentioned pressure-sensitive adhesive film for over-laminating requires a larger number of release sheets than the pressure-sensitive adhesive film for over-laminating in the final use form, and the pressure-sensitive adhesive film for over-laminating is adhered to an intended adherend. In such a case, the release sheet must be peeled off, which not only increases the product cost but also causes garbage and adversely affects the natural environment.

For the above reasons, in order to obtain a pressure-sensitive adhesive film for over-laminating which does not require a release sheet, it is preferable that a transparent film is provided with a release agent layer on one surface and a pressure-sensitive adhesive on the other surface.

In order to solve the above problem, the present inventor has already disclosed in Japanese Patent Application No. 10-241503 a silicone-based release agent or a silicone-modified resin-based release agent layer provided on one surface of a transparent base material. A pressure-sensitive adhesive layer having a specific glass transition point is provided on the surface, the peeling force of the pressure-sensitive adhesive layer with respect to the release agent layer is in a specific range, and the pressure-sensitive adhesive tape including the release agent layer and the pressure-sensitive adhesive layer is intermittently rewound. There has been proposed a pressure-sensitive adhesive tape characterized in that no trace of peeling is produced on the surface of the pressure-sensitive adhesive layer when peeled, or the trace of peeling of the pressure-sensitive adhesive layer disappears instantaneously after bonding to another adherend.

The pressure-sensitive adhesive used for the above-mentioned proposed pressure-sensitive adhesive tape includes various types of pressure-sensitive adhesives of rubber type, acrylic type, vinyl ether type, etc., and solvent type or non-solvent type. The agent is weather resistant,
Peeling force stability over time, high percentage used because of excellent transparency, furthermore, those obtained by emulsifying the acrylic pressure-sensitive adhesive do not contain any organic solvent, so there is no adverse effect on the human body, and it is environmentally friendly. Because of its gentleness, it is a pressure-sensitive adhesive that has received particular attention in recent years.

However, when the emulsion-type acrylic pressure-sensitive adhesive is used for removing the solvent from the acrylic pressure-sensitive adhesive, not only the water resistance is reduced but also the winding pressure is reduced irrespective of the glass transition point and the peeling force of the pressure-sensitive adhesive. It has been newly found that traces of peeling may occur when returning. In addition, when using the emulsion-type acrylic pressure-sensitive adhesive and manufacturing by a transfer method of applying a pressure-sensitive adhesive to a release sheet, not only a release sheet that eventually becomes dust as described above is required, but also It is necessary to add a relatively large amount of a wetting agent such as a surfactant in order to easily wet the release agent layer of the release sheet of the acrylic emulsion-type pressure-sensitive adhesive, and as a result, there is a problem that water resistance is reduced. Was.

[0010]

The object of the present invention is to provide a water-resistant, hardly peeling-off trace of the pressure-sensitive adhesive layer even when an acrylic emulsion-type pressure-sensitive adhesive is used, and to provide a transparent film even when adhered to an adherend. It is an object of the present invention to provide an environment-friendly pressure-sensitive adhesive film for over-laminating which does not impair the adhesiveness and does not require a release sheet.

[0011]

The present inventors have conducted intensive studies to solve the above-mentioned drawbacks. As a result, the release agent layer has rubber elasticity and the adhesive is an acrylic emulsion type adhesive. By limiting the contact angle of the pressure-sensitive adhesive layer surface to water to a specific range, not only water resistance and weather resistance, but also hardly causes peeling traces on the pressure-sensitive adhesive layer, and excellent transparency,
In addition, they have found that an adhesive film for overlaminate that does not require a release sheet can be provided, and the present invention has been completed.

That is, in order to solve the above-mentioned problems, the present invention is directed to an adhesive film for over lamination, which is laminated in the order of a release agent layer / a transparent film / an adhesive layer, wherein the release agent layer has rubber elasticity. And the pressure-sensitive adhesive is an acrylic emulsion-type pressure-sensitive adhesive;
Is a contact angle (measured after 60 seconds with a drop amount of 5 μl in an environment of 23 ° C.) of 70 ° to 120 °. Preferably, the acrylic pressure-sensitive adhesive is directly applied to the transparent film,
Preferably, the release agent is a silicone-based release agent.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The pressure-sensitive adhesive film for over lamination of the present invention is formed by laminating a release agent layer / a transparent film / a pressure-sensitive adhesive layer in this order, wherein the pressure-sensitive adhesive is an acrylic emulsion type pressure-sensitive adhesive. Is characterized by having a contact angle with water in a specific range.

The transparent film is not particularly limited, and examples thereof include a polypropylene film, a polyester film, and a polyethylene film. Among them, the substrate is high in strength but relatively inexpensive in spite of its softness. Axial stretched polypropylene film (OP
P) is preferably used.

The above-mentioned transparent film may be one which has been subjected to a corona treatment and / or an anchor treatment on one or both sides thereof for the purpose of improving the adhesion and / or coating properties with a release agent or a pressure-sensitive adhesive. However, since excessive anchor treatment or excessive corona treatment impairs the transparency of the pressure-sensitive adhesive film, it is preferable to use a transparent film that has been processed to such an extent that the transparency of the pressure-sensitive adhesive film is not impaired.

Further, the surface to which the pressure-sensitive adhesive is applied, the surface to which the release agent is applied, or the surface of the release agent layer is partially subjected to printing having some degree of transparency (there may be an opaque printed portion in some cases). May be. However, in order not to lose the information intended by the adherend, it is necessary to use only partial printing so as not to cover the printed part of the adherend, or to use a transparent ink. preferable.

The release agent forming the release agent layer has rubber elasticity. The term “polymer having rubber elasticity” as used herein refers to a polymer having a glass transition point of room temperature or lower, preferably -20 ° C. or lower, and exhibiting rubber properties at room temperature, and the type thereof is not particularly limited. A release agent layer comprising at least one selected from a silicone release agent, polyisobutylene, butyl rubber, and the like, and a release agent layer composed of a silicone release agent that is particularly excellent in terms of releasability, transparency, etc. Is preferred. The glass transition point can be measured by a DSC (differential thermal scanning calorimeter) [manufactured by Seiko Denshi Kogyo Co., Ltd., DSC22 (or a measuring device having an equivalent function)]. Indicates that each sample (OP
About 10 mg of a sample in which a release agent layer was provided on a P film, an OPP single film) was heated from 0 ° C. to 150 ° C. (heating rate: 5 ° C./min), and two glass transition points were obtained. Is determined as the glass transition point of the release material, which is different from the glass transition temperature of the OPP single film obtained in the above.

More detailed selection of these release agents depends on the type of the adhesive selected from the qualities such as the adhesive strength to the adherend, tack and holding power. By the way, when a release agent having no rubber elasticity is used, the release form between the adhesive layer and the release agent layer is discontinuous release regardless of the type of the adhesive (hereinafter, also referred to as zipping phenomenon). This is not preferable because it is easy to cause peeling marks on the pressure-sensitive adhesive layer. Such a trace of peeling of the pressure-sensitive adhesive layer can be a fatal defect in the quality of the pressure-sensitive adhesive film for over-laminating which requires transparency.

[0019] release agent having the rubber elasticity, those silica structure having SiO ₂ units to control when using a silicone release agent, the peeling strength, adhesion, coating strength, a blocking or the like, SiO ₂ Units and (CH ₃ ) ₃ Si
A heavy release control agent, a crosslinking agent, a reaction retarder, a silane coupling agent, which is at least one member selected from those having a resin structure having O _1/2 units or CH ₂ ＣＨCH (CH ₃ ) ₂ SiO _1/2 units. Other additives such as cellulose derivatives, silicone resin fine powder, and ethylene-vinyl acetate copolymer (EVA) may be added to such an extent that the curability of silicone is not impaired.

The amount of the release agent for forming a release agent layer on the pressure-sensitive adhesive film is preferably 0.05 to 5 g / m ² ,
0.1-1 g / m < ² > is more preferable. Application amount is 0.05
If it is less than g / m ² , uniform peeling performance with the pressure-sensitive adhesive layer may not be obtained, and the peeling force may increase, making it difficult to rewind the pressure-sensitive adhesive film.
^If it exceeds ² , the transparency of the adhesive film will be impaired,
Alternatively, the conditions for applying and drying the release agent need to be strict (drying at a high temperature for a long time), which is not preferable because the processing speed is slowed down, the economical efficiency such as high power cost is reduced, and the cost is increased.

The method of applying the release agent is not particularly limited, and examples thereof include a gravure direct method, a gravure reverse method, a bar or rod coating, and a three-roll coating. The curing temperature varies depending on the type of release agent applied, the structure and performance of the drying device,
70-140 degreeC is desirable.

On the other hand, the pressure-sensitive adhesive forming the pressure-sensitive adhesive layer is an acrylic emulsion-type pressure-sensitive adhesive, and the contact angle of water on the surface of the pressure-sensitive adhesive layer provided on the transparent film (at 23 ° C. environment)
The measurement is not particularly limited as long as the drop amount is 5 μl and measured after 60 seconds) is 70 ° to 120 °, for example, (a) alkyl group,
(b) hydroxyl group, (c) epoxy group, (d) alkoxyl group, (e) ethylene oxide group, (f) amino group, (g) amide group, (h) carboxyl group, (i) halogen atom, (j )
A vinyl monomer having a phosphate group, (k) sulfonic acid group, (l) silane group, (m) urethane group, (n) phenyl group, (o) benzyl group, (p) tetrahydrofurfuryl group, etc. q)
It is an acrylic emulsion type pressure-sensitive adhesive polymerized by a known method such as an emulsion polymerization method using a polymerization initiator, a chain transfer agent or the like, an emulsifier, a dispersant or the like for each monomer such as other copolymerizable monomers. A tackifier, a plasticizer, a thickener, a softener, a stabilizer, a colorant, a pigment, and the like may be added to the acrylic emulsion-type pressure-sensitive adhesive.

The above-mentioned monomers are specifically (a) methyl (meth) acrylate, ethyl (meth) acrylate, isopropyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate as vinyl monomers having an alkyl group. , Butyl (meta)
Acrylate, hexyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isoamyl (meth) acrylate, isooctyl (meth) acrylate, n-octyl (meth) acrylate, dodecyl (meth) acrylate, isobutyl ( (Meth) acrylate and the like.

(B) Examples of the vinyl monomer having a hydroxyl group include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate,
-Hydroxybutyl (meth) acrylate, 3-chloro-2-hydroxyethyl (meth) acrylate, and the like. (c) Examples of the vinyl monomer having an epoxy group include glycidyl (meth) acrylate and methyl glycidyl (meth) acrylate.

(D) Examples of the vinyl monomer having an alkoxyl group include methoxyethyl (meth) acrylate, ethoxyethyl (meth) acrylate, butoxyethyl (meth) acrylate, and phenoxyethyl (meth) acrylate. (e) Examples of the vinyl monomer having an ethylene oxide group include diethylene glycol (meth) acrylate, methoxydiethylene glycol (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, phenoxydiethylene glycol (meth) acrylate,
Phenoxy polyethylene glycol (meth) acrylate and the like.

(F) Examples of the vinyl monomer having an amino group include dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, N-ter
t-butylaminoethyl (meth) acrylate, methacryloyloxyethyltrimethylammonium chloride (meth) acrylate, and the like. (g) Examples of the vinyl monomer having an amide group include (meth) acrylamide, N-methylol (meth) acrylamide, N-methoxymethyl (meth) acrylamide,
N, N'-methylenebis (meth) acrylamide and the like.

(H) Examples of the vinyl monomer having a carboxyl group include acrylic acid, methacrylic acid, itaconic acid,
Maleic acid, fumaric acid, 2-methacryloyloxysuccinic acid, 2-methacryloyloxyethylmaleic acid,
2-methacryloyloxyethyl phthalic acid, 2-methacryloyloxyethyl hexahydrophthalic acid and the like can be mentioned.

(I) Examples of the vinyl monomer having a halogen atom include trifluoroethyl (meth) acrylate,
Pentadecafluorooxyethyl (meth) acrylate, 2-chloroethyl (meth) acrylate, 2,3-
Examples thereof include dibromopropyl (meth) acrylate and tribromophenyl (meth) acrylate. (j) Examples of the vinyl monomer having a phosphate group include 2-methacryloyloxyethyldiphenyl phosphate (meth) acrylate, trimethacryloyloxyethyl phosphate (meth) acrylate, and triacryloyloxyethyl phosphate (meth) acrylate.

(K) Examples of the vinyl monomer having a sulfonic acid group include sodium sulfopropyl (meth) acrylate, sodium 2-sulfoethyl (meth) acrylate, sodium vinyl sulfonate, sodium styrene sulfonate, and 2-acrylamido-2-methyl. Sodium propanesulfonate, sodium 3-allyloxy-2-hydroxypropanesulfonate and the like can be mentioned.

(L) Vinyl monomers having a silane group include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (β-methoxyethyl) silane,
Vinyl triacetyl silane, methacryloyloxypropyl trimethoxy silane and the like can be mentioned. (m) Examples of the vinyl monomer having a urethane group include urethane (meth) acrylate.

(N) Examples of the vinyl monomer having a phenyl group include phenyl (meth) acrylate and p-tert.
-Butylphenyl (meth) acrylate, o-biphenyl (meth) acrylate and the like. (o) Examples of the vinyl monomer having a benzyl group include benzyl (meth) acrylate.

(P) Examples of the vinyl monomer having a tetrahydrofurfuryl group include tetrahydrofurfuryl (meth) acrylate. (q) Other copolymerizable monomers include styrene, chlorostyrene, α-methylstyrene, vinyltoluene,
Vinyl chloride, vinyl acetate, vinyl propionate, Veo
va10 (manufactured by Shell Chemical Co., Ltd., vinyl alkylate compound), acrylonitrile, vinylpyridine and the like.

In the above monomers, examples of the vinyl monomer having a hydrophilic group include acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, monoalkylmaleic acid, monoalkylitaconic acid and monoalkylfumaric acid. Ethylenically unsaturated carboxylic acid-containing monomer, methoxyethyl acrylate, alkoxyalkyl (meth) acrylate such as ethoxyethyl acrylate, carboxylic acid-modified rosin ester, caprolactone adduct of (meth) acrylic acid, hydroxyethyl (meth) acrylate, ( (Meth) hydroxypropyl acrylate,
(Meth) acrylamide, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate and the like.

Incidentally, the contact angle of water on the surface of the pressure-sensitive adhesive layer provided on the transparent film (60 ° C at 23 ° C. and 5 μl dropwise)
(Measured after 2 seconds) is less than 70 degrees, the adhesive film for over-lamination cannot exhibit the intended water resistance, but it also becomes easy to hold air bubbles after being adhered to the adherend, or the adhesive strength to the adherend is reduced. It is not preferable because it may decrease. On the other hand, when the temperature exceeds 120 degrees, although the water resistance is improved, when the adhesive film for over-lamination is rewound, the adhesive layer is apt to peel off when it is rewound, and as a result, the transparency is improved when the adhesive film is bonded to the intended adherend. Is not preferred because it may be impaired.

The pressure-sensitive adhesive film for over-laminate of the present invention comprises:
It is necessary that (1) the release agent layer has rubber elasticity, and (2) the adhesive is an acrylic emulsion type adhesive, and the contact angle of the surface of the adhesive layer with water is 70 to 120 degrees. If one of (1) and (2) is out of the range, the desired performance of the present invention cannot be exhibited. For example, when a release layer having no rubber elasticity is used, the release form between the pressure-sensitive adhesive layer and the release agent layer as described above, regardless of the type of the pressure-sensitive adhesive, the release form easily causes a zipping phenomenon, and the pressure-sensitive adhesive If the contact angle of the pressure-sensitive adhesive layer to water is out of the above range, problems such as a decrease in water resistance, generation of bubbles, or a trace of peeling may occur.

The contact angle of water on the surface of the pressure-sensitive adhesive layer provided on the transparent film is determined by dropping water from a micro syringe onto the surface of the pressure-sensitive adhesive layer provided on one surface of the transparent film (the surface opposite to the surface of the release agent layer). Is a measured value. In the present invention, the contact angle at the point of time when 60 seconds have elapsed after the dropping of water is evaluated. By the way, when the value measured immediately after dropping or the value measured after 60 seconds is used, the overlamination of the present invention is used. Accurate correlation with the water resistance of the pressure-sensitive adhesive film, the generation of air bubbles after bonding to the adherend, and the trace of peeling of the pressure-sensitive adhesive layer could not be obtained.

The effect of the difference in the contact angle of water on the surface of the pressure-sensitive adhesive layer provided on the transparent film on the properties of the overlaminating film has not yet been sufficiently clarified. The wettability of the agent layer with respect to water is increased, and at the same time, the hygroscopicity is also increased, and air bubbles are easily generated due to evaporation of moisture from the inside of the adhesive due to temperature change after bonding to the adherend, while contact When the angle increases, the wettability of the pressure-sensitive adhesive layer with respect to water decreases, but the peeling energy with the release agent layer increases, which easily leads to deformation of the pressure-sensitive adhesive layer. I guess.

As a method for adjusting the contact angle of the pressure-sensitive adhesive layer surface provided on the transparent film with water, in addition to adjusting the addition amount of a wetting agent such as a surfactant, the addition amount of a vinyl monomer having a hydrophilic group may be adjusted. Adjustment methods and methods for adjusting the degree of polymerization of the pressure-sensitive adhesive are exemplified. However, what should be noted in the above adjustment method is that if an additive such as a surfactant or a vinyl monomer having a hydrophilic group is added too much, the adhesive strength is reduced, and if the polymerization degree of the adhesive is too high, the adhesive layer is And the release agent layer is likely to be in the form of a zipper.

The surfactant used as the wetting agent is not particularly limited as long as it can improve the wettability of the pressure-sensitive adhesive on the transparent substrate. As the anionic surfactant, sodium alkylbenzene sulfonate is used. ,
Known surfactants such as fatty acid soaps and nonionic surfactants such as sorbitan esters and polyoxyethylene alkyl ethers may be mentioned.

The amount of the pressure-sensitive adhesive to be applied is appropriately selected depending on the type and thickness of the substrate to be used.
0 g / m ² is preferable, and more preferably 5 to 30 g / m ²
m ² . When the coating amount is less than 3 g / m ² , the adhesive strength when sticking the over-laminate adhesive film to another adherend may decrease, and when it exceeds 50 g / m ² , the pressure-sensitive adhesive Because the anchoring property is deteriorated, the adhesive may protrude from the edge of the adhesive film for over lamination, or the adhesive may remain on the release layer when rewinding, and problems such as reduced transparency may occur. It is.

The coating method of the acrylic emulsion type pressure-sensitive adhesive is not limited at all, and examples thereof include a comma coating method, a reverse coating method, a gravure coating method, a reverse gravure method, a kiss coating method, a knife coating method, a bar or rod coating method, A method of directly coating one surface of the transparent film (the surface opposite to the surface of the release agent layer) by a lip coating method, and a method of applying an adhesive to a release sheet and then transferring it to a transparent film can be used, but the direct coating method is preferable. . In the method of applying an adhesive on a release sheet and transferring it to a transparent film,
In order to increase the wettability of the pressure-sensitive adhesive to the release agent layer, it is necessary to add a large amount of a wetting agent such as a surfactant, or if the release sheet surface has low smoothness or a rough surface, the surface is uneven. This is because it is not preferable because problems such as a decrease in transparency and a decrease in adhesive strength are liable to occur due to factors such as copying as it is. Furthermore, it is possible to apply with a low viscosity, and it is a one-way method without returning of the adhesive, without generating accumulations such as bubbles,
The slot die coating method which can maintain the transparency of the substrate as much as possible because the coated surface has high smoothness is particularly preferable.

When the pressure-sensitive adhesive is applied by the direct coating method as described above, the contact angle of the pressure-sensitive adhesive to the coated surface of the transparent film (the solid content of the pressure-sensitive adhesive is adjusted to 20% by mass, 5 μl after 60 seconds at 23 ° C.)
It is preferable that it is 80 degrees. The reason is that the contact angle of the pressure-sensitive adhesive with respect to the coated surface of the transparent film is 80%.
If it exceeds the degree, the leveling property of the pressure-sensitive adhesive with respect to the film is reduced and repelling on the coated surface, coating unevenness and the like are likely to occur.On the other hand, if the contact angle is less than 20 degrees, the leveling property of the pressure-sensitive adhesive with respect to the film is reduced. Although it improves, it is necessary to add a large amount of a wetting agent such as a surfactant to the adhesive, or it is necessary to perform excessive anchor treatment or corona treatment on the transparent film, thereby reducing water resistance and adhesive strength. This is because defects such as a decrease in transparency and a decrease in transparency are likely to occur. Examples of the method for adjusting the contact angle include adjusting the amount of a wetting agent such as a surfactant as described above, and performing the anchor treatment or corona treatment on the adhesive-coated surface of the transparent base material in addition to the hydrophilicity method. A method of adjusting the amount of the vinyl monomer having a group may be used.

[0043]

EXAMPLES The present invention will be described in more detail with reference to the following examples, which, of course, are not intended to limit the present invention. In the Examples and Comparative Examples, "parts" and "%" indicate numerical values based on mass of solid components or active ingredients, unless otherwise specified.

Example 1 <Formation of Release Agent Layer> A silicone-based release agent (Toray Dow) was used as a release agent on the corona-treated surface of an OPP film base material (manufactured by Oji Paper Co., Ltd., PU-102, 25 μm, single-side corona-treated product). 90 parts of Corning Co., Ltd., SD-7234), 10 parts of MQ resin (Toray Dow Corning Co., Ltd., SD-7292) 10
Was dissolved in toluene, 1 part of a catalyst (manufactured by Toray Dow Corning Co., Ltd., SRX-212) was added, and the mixed solution stirred well was used as a release agent coating liquid, and this was adjusted to have a solid content of 0.3 g / m ^2. Coating and drying were performed on the corona-treated surface of the base material to obtain a release agent layer. This is referred to as a release film (I).

<Production of adhesive> As shown in Table 1, 85 parts of 2-ethylhexyl acrylate, 10 parts of ethyl acrylate, 2 parts of acrylic acid, 3 parts of vinyl acetate, 200 parts of ion-exchanged water, and ammonium persulfate as shown in Table 1. 0.
3 parts and 0.8 part of an anionic surfactant (Emal NC-35, manufactured by Kao Corporation) are reacted by a known emulsion polymerization method, and 100 parts of the aqueous dispersion is reacted with a nonionic surfactant (Emulgen 810). , Kao Corporation) was added to produce an acrylic emulsion type pressure-sensitive adhesive (a) having a solid content of 36.3%.

<Production of Overlaminating Adhesive Film> Then, an acrylic emulsion type adhesive (a) was coated on the surface opposite to the surface provided with the release agent layer by a coating method using a slot die method so that the coating amount was 10 g / m ^2. Coating speed 30 so that
Direct coating was performed at 0 m / min to produce an adhesive film for over-laminate.

Example 2 The monomer composition and additives were changed as shown in Table 1 (b).
Except for using the pressure-sensitive adhesive (b) produced in the same manner as in Example 1, an adhesive film for overlaminating was produced using the materials and methods described in Example 1.

Example 3 The monomer composition and additives were changed as shown in Table 1 (c).
Except for using the pressure-sensitive adhesive (c) produced in the same manner as in Example 1, an adhesive film for overlaminating was produced using the materials and the method described in Example 1.

Comparative Example 1 The monomer composition and additives were changed as shown in Table 1 (d).
Except for using the pressure-sensitive adhesive (d) produced in the same manner as in Example 1, an adhesive film for over-laminate was produced using the materials and the method described in Example 1.

Comparative Example 2 The monomer composition and additives were changed as shown in Table 1 (e).
An adhesive film for over-laminate was produced using the materials and the method described in Example 1 except that the adhesive (e) produced in the same manner as in Example 1 was used.

Comparative Example 3 100 parts of natural rubber (RSS # 3) as an adhesive and 90 parts of a petroleum resin (Quinton S-100, as a tackifier)
Softening point 94 ° C., manufactured by Zeon Corporation) 25 parts of a terpene-based liquid softening resin (Dimaron, manufactured by Yasuhara Chemical Co., Ltd.) as a softening agent, 0.8 part of a crosslinking agent (Millionate MR-10)
0, manufactured by Nippon Polyurethane Co., Ltd.) and a release film according to Example 1 obtained by dissolving a composition comprising 1 part of an antioxidant (Nocrack NS-5, manufactured by Ouchi Shinko Chemical Co., Ltd.) in toluene by the comma direct method. Coating was performed on the surface opposite to the release agent layer surface of (I) so as to have a coating amount of 15 g / m ² to obtain an adhesive film for overlaminating.

Comparative Example 4 OPP film substrate (PU-102, 2 manufactured by Oji Paper Co., Ltd.)
On the corona-treated surface of 5 μm, one-sided corona-treated product), as a release agent, a long-chain alkyl group-containing polymer (manufactured by Yushi Kogyo Co., Ltd., Piroyl 1010) was dissolved in toluene heated to 60 ° C. as a solvent and stirred well. The solution was used as a release agent coating liquid, and the solid content of 0.1% was applied to the corona-treated surface of the base material.
Coating and drying were performed to 1 g / m ² to obtain a release agent layer.

Next, the same acrylic emulsion-type pressure-sensitive adhesive (a) as in Example 1 was applied on the surface opposite to the surface provided with the release agent layer by a coating method using a slot die method to a coating amount of 10 g.
/ M ² to prepare an adhesive film for over-laminate.

The pressure-sensitive adhesive films for overlamination obtained in each of the above Examples and Comparative Examples were evaluated by the following methods, and the results are shown in Table 2.
In the evaluation results, の indicates good practicality, Δ indicates practical limit, and X indicates no practicality.

<Removal marks> Seal printing machine OPM, Onda Seisakusho
-W150-3S intermittently rewinds the adhesive film for over lamination, and applies a pressure of 0.3 kg / m ² to the printed substrate.
Was performed, and peeling traces on the pressure-sensitive adhesive layer surface when the film was rewound and after overlamination were visually observed.

<Transparency> The transparency of the pressure-sensitive adhesive film for overlaminating was measured using a haze meter (HGM- manufactured by Suga Test Instruments Co., Ltd.).
2K) was used to measure haze.

<Water resistance> The adhesive film for over lamination was made to have a size of 100 mm × 50 mm.
2 μm PET film (E-5000, manufactured by Toyobo Co., Ltd.)
Was immersed in water at 23 ° C. for 7 days, and evaluated according to the following evaluation criteria. ：: The haze value of the adhesive film for overlamination (entire surface) after immersion is within 150% of the haze value of the adhesive film for overlamination before immersion. Δ: The haze value of the overlaid adhesive film after immersion partially exceeded 150% of the haze value of the overlaid adhesive film before immersion. ×: The haze value of the adhesive film for overlamination (overall surface) after immersion exceeds 150% with respect to the haze value of the adhesive film for overlamination before immersion (impractical).

<Weather Resistance> The pressure-sensitive adhesive film for over lamination was made 100 mm × 50 mm, and the corona-untreated 2
5 μm OPP film (PU-002, manufactured by Oji Paper)
And an energy of 10 from the surface on which the adhesive film for over lamination is adhered in an environment of 63 ° C. and 20% RH.
UV irradiation was performed at 0 mW / cm ² for 4 hours. L ^* a ^* b ^* (CI before and after UV irradiation of the adhesive film for over lamination
(ELAB display) were measured with a color computer (manufactured by Suga Test Instruments Co., Ltd.), and evaluated according to the following evaluation criteria. ○: to b ^* value of the over-laminating adhesive film before UV irradiation, b ^* values of the over-laminating adhesive film after UV irradiation treatment is within 120%. Δ: The b ^* value of the adhesive film for overlamination after UV irradiation treatment was within 150% of the b ^* value of the adhesive film for overlamination before UV irradiation. ×: to b ^* value before the over laminating adhesive film for UV radiation, b ^* values of the over-laminating adhesive film after UV irradiation treatment exceeds 150%.

<Bubble> One-sided corona-treated 25 μm OP
Offset printing was performed on the corona-treated surface of a P film (PU-102, manufactured by Oji Paper Co., Ltd.), and an adhesive film for over-laminate was applied to the printed surface in a size of 50 mm × 25 mm. Was evaluated. ：: No bubbles were generated in the adhesive film for over-lamination, which was good. C: Some bubbles are generated in the adhesive film for over-lamination, but the degree does not impair the transparency. ×: Bubbles are generated in the adhesive film for over-laminate, and transparency is impaired.

[0060]

[Table 1]

[0061]

[Table 2]

As is clear from Table 2, Examples 1 to 3
Such a film for over lamination does not require a release sheet, does not cause peeling marks on the pressure-sensitive adhesive layer, stickability, transparency,
Quality excellent in water resistance and weather resistance was obtained.

The pressure-sensitive adhesive film for over lamination of Comparative Example 1 has poor water resistance and generates bubbles in the sticking test. In Comparative Examples 2 and 4, peeling marks are formed on the surface of the pressure-sensitive adhesive layer when the pressure-sensitive adhesive film for over-lamination is intermittently rewound, and the peeling marks are left even after bonding to the base material, and the transparency is impaired. Was something. The pressure-sensitive adhesive film for overlamination as in Comparative Example 3 not only caused peeling marks on the surface of the pressure-sensitive adhesive layer, but also had extremely poor transparency and weather resistance.

[0064]

According to the present invention, an acrylic emulsion-type pressure-sensitive adhesive is used, and a release sheet is not required, so that it is environmentally friendly. Moreover, since the pressure-sensitive adhesive layer is hardly peeled off and excellent in water resistance, weather resistance, etc., It has a great value as an adhesive film for over lamination, which is indispensable for retaining various information for a long time.

Continued on the front page F-term (reference) 4F100 AK07 AK25 AK25C AK25J AK52 AK52A AL01 AN00A AN02A AT00B BA03 BA07 BA10A BA10C BA15 CA18 EH46 EH46C EJ38 EJ55 GB90 JB07 JB07C JL00 JL09 J02 CC14 J03A01B01 J02A CD06 DA04 DB01 FA04

Claims (3)

[Claims] An adhesive film for lamination comprising a release agent layer / a transparent film / an adhesive layer laminated in this order, wherein the release agent layer has rubber elasticity and the adhesive is an acrylic emulsion type adhesive. And the contact angle of the pressure-sensitive adhesive layer surface with water (measured after 60 seconds with a drop volume of 5 μl in an environment of 23 ° C.)
From 70 to 120 degrees. 2. The pressure-sensitive adhesive film according to claim 1, wherein the acrylic pressure-sensitive adhesive is directly applied to the transparent film. 3. The pressure-sensitive adhesive film according to claim 1, wherein the release agent is a silicone-based release agent.