JP2000086984A - Production of tacky sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a photo-setting type tacky tape by which various problems according to disposal of release films are solved and characteristics such as nonpollution, energy saving or resource saving are further improved. SOLUTION: (1) (A) Ultraviolet ray transmitting films relatively different in peel strength between the front and back surfaces are used for both of a substrate and a release film and (2) a photoreactive composition layer is formed between a heavy release surface of the ultraviolet ray transmitting film (A1) having a high peel strength and a light release surface of the ultraviolet ray transmitting film (A2) having a low peel strength. (3) The resultant multilayered sheet is then irradiated with ultraviolet rays through at least either one of the ultraviolet ray transmitting films (A) in the process for conveying the multilayered sheet to polymerize the photoreactive composition and form a tacky agent layer. (4) The ultravoilet ray transmitting film (A2) is subsequently peeled from the tacky agent layer and (5) the peeled ultaviolet ray transmitting film (A2) is then reversed and reused as the ultraviolet ray transmitting film (A1).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a pressure-sensitive adhesive sheet, and more particularly to a method for producing a photocurable pressure-sensitive adhesive sheet using a photoreactive composition.

[0002]

2. Description of the Related Art Conventionally, a photoreactive composition containing an acrylate monomer, a vinyl monomer copolymerizable with the acrylate monomer, a photoinitiator, and the like is applied on a substrate and cured by irradiation with ultraviolet rays. Thus, a method for producing an adhesive tape is known. Such UV-curable pressure-sensitive adhesive tapes can be manufactured in a short time without the use of solvents, and are attracting attention as a part of solvent-free technology with features such as pollution-free, energy-saving, and resource-saving. I have. However, since many acrylate-based monomers and vinyl-based monomers have high volatility, the production of pressure-sensitive adhesive tapes using a photoreactive composition has a poor working environment in production and the volatilized monomers are exposed to ultraviolet rays. There is a problem that the irradiation lamp and other equipment are contaminated. In addition, radical polymerization by irradiation of ultraviolet rays of an acrylate-based monomer or the like has polymerization inhibition by oxygen. Therefore, if the atmosphere is inertized and oxygen is cut off, the production cost increases.

[0003] Conventionally, in order to manufacture an ultraviolet-curable pressure-sensitive adhesive tape, in many cases, a photoreactive composition is applied on a substrate, and then an ultraviolet ray is applied on a coating layer (photoreactive composition layer). A method of covering a permeable release film to prevent volatilization of monomers and inhibition of polymerization due to oxygen has been adopted. In this method, a multilayer sheet having a layer structure of a substrate / photoreactive composition layer / release film is transported using a group of rolls,
In the transportation process, ultraviolet rays are irradiated through a release film to polymerize the photoreactive composition to form an adhesive layer, and then the release film is released from the adhesive layer. The pressure-sensitive adhesive sheet composed of the base material and the pressure-sensitive adhesive layer is wound on a take-up roll to form a product.

More specifically, FIG. 5 shows an example of a manufacturing process of a conventional photocurable pressure-sensitive adhesive tape. Substrate feeding roll 5
The photoreactive composition 54 is applied onto the substrate 61 by the application rolls 52, 52 through the roll 58 and the rolls 58. The release film 62 is fed from the release material feeding roll 51, and the base material 61 is fed by the rolls 59 and 59.
The release film 62 is laminated on the photoreactive composition layer 63 formed thereon. In the transportation process, the laminated multilayer sheet is irradiated with ultraviolet rays from the ultraviolet irradiation device 55 via a release film, whereby the photoreactive composition is polymerized and a pressure-sensitive adhesive layer is formed. Next, roll 6
At 0 and 60, the release film is released from the pressure-sensitive adhesive layer, and is taken up by a release material take-up roll 56. on the other hand,
The base material / adhesive layer is taken up by a take-up roll 57 to form an adhesive tape product. However, in this method, the release film that has been peeled off before the adhesive sheet is wound up may be discarded as it is because the release-treated surface falls off or wrinkles may occur, or may be reused at most two to three times. After being disposed of. Therefore, the release film is a wasteful use of resources. Disposal of the release film also increases manufacturing costs and raises waste disposal problems.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing a photocurable pressure-sensitive adhesive tape which solves various problems associated with the disposal of a release film and further improves characteristics such as pollution-free, energy-saving and resource-saving. To provide. The present inventors have conducted intensive studies to overcome the above-mentioned problems of the prior art, and as a result, in the manufacturing process of the photocurable pressure-sensitive adhesive tape, based on an ultraviolet-permeable film having relatively different peeling forces on the front and back surfaces. Used as both a material and a release film, by inverting the UV-transmissive film that was first used as the release film and reusing it as the base film, the adhesive film was manufactured without discarding the release film. I found something to gain.

[0006] That is, an ultraviolet-permeable film having different peeling forces on the front and back sides uses a heavy peeling surface having a large peeling force and a light peeling surface having a small peeling force to form a substrate film (heavy peeling side film). As a release film (light release surface side film). Then, a photoreactive composition layer is formed between the heavy release surface and the light release surface, and a pressure-sensitive adhesive layer is formed by irradiating ultraviolet rays in a transport process,
After peeling off the release film, the release film can be inverted and reused as a substrate film by using the heavy release surface side. The ultraviolet-permeable film having relatively different peeling forces on the front and back sides can be prepared by using a known technique such as one-sided silicone treatment or one-sided corona treatment. According to the method of the present invention, polymerization inhibition due to volatilization of monomers and oxygen is prevented, and since there is no need to dispose of a release film, characteristics such as pollution-free, energy-saving, and resource-saving of a photocurable adhesive tape can be obtained. Even better. The present invention has been completed based on these findings.

[0007]

According to the present invention, a photoreactive composition layer is formed between a substrate and a release film, and ultraviolet rays are applied to the photoreactive composition layer in the process of transporting the photoreactive composition layer. Irradiation, polymerize the photoreactive composition to form a pressure-sensitive adhesive layer, and then release the release film from the pressure-sensitive adhesive layer. And (2) a UV-permeable film (A2) having a large peeling force and a UV-permeable film (A2) having a large peeling force. (3) forming a photoreactive composition layer between the photoreactive composition layer and the light release surface having a small release force, and (3) irradiating ultraviolet rays through at least one of the ultraviolet transparent films in the process of transporting the photoreactive composition layer; The adhesive composition is polymerized to form an adhesive layer. Then, (4) the ultraviolet ray transmitting film (A2) is peeled from the pressure-sensitive adhesive layer, and (5) the peeled ultraviolet ray transmitting film (A2) is inverted and reused as the ultraviolet ray transmitting film (A1). A method for producing a pressure-sensitive adhesive sheet is provided.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for producing an adhesive tape of the present invention will be described with reference to the drawings. In the present invention, as the base material and the release film, an ultraviolet-transparent film having a relatively different release force (also referred to as releasability or surface energy) between the front surface and the back surface is used. A photoreactive composition layer is formed between the heavy release surface and the light release surface of the ultraviolet ray permeable film, and the photoreactive composition is applied to either the heavy release surface or the light release surface. Is also good.

FIG. 1 is a schematic diagram showing a manufacturing process employing an example of a coating method for applying a photoreactive composition to a light release surface side of an ultraviolet-permeable film having a small release force. The ultraviolet-permeable film (A2) 13 is unwound from the base material unwinding roll, and the photoreactive composition 3 is applied from the roll 13 to the light-releasing surface of the ultraviolet-permeable film (A2) 13 via the coating rolls 2 and 2. Then, the photoreactive composition layer 14 is formed.
On the photoreactive composition layer 13, the heavy release surface side of the ultraviolet-transmissive film (A1), which has been inverted and reused, is laminated. The multilayer sheet having each of these layers is irradiated with ultraviolet rays by the ultraviolet irradiation device 4 during the transportation process. After the irradiation step, the multilayer sheet
Via roll 7 and rolls 8, 8, the substrate / adhesive layer is
The adhesive sheet is taken up by a take-up roll 5. The ultraviolet-permeable film (A2) on the light release surface side was released from the pressure-sensitive adhesive layer as a release film, and then rolls 9, 10,
After passing through 11 and 6, the front and back are turned over, and the heavy release surface side is covered on the photoreactive composition layer 14 as the ultraviolet-transmitting film (A1) of the base material. In the initial stage of the manufacturing process, the film is fed out without the photoreactive composition layer so that the light release surface side and the heavy release surface side of the ultraviolet ray permeable film 13 face each other as shown in FIG. The ultraviolet-transparent film 13 is unreeled from the roll 1 and set.

FIG. 2 is a schematic view showing a manufacturing process employing another example of a coating method for applying a photoreactive composition to a light release surface side of an ultraviolet ray permeable film having a small release force. In FIG. 2, after the UV irradiation step, the UV-permeable film (A2) on the light release surface side is peeled from the pressure-sensitive adhesive layer, and is turned upside down via rolls 9, 10, 11, 7, and 6. Then, the heavy release surface side is coated on the photoreactive composition layer 14 as the ultraviolet transparent film (A1) of the base material. After the ultraviolet-transparent film (A2) is peeled off from the pressure-sensitive adhesive layer, it is inverted in FIG. 1 through the lower side of the ultraviolet irradiation device 4, whereas in FIG. Is inverted through. In any case, after the reversal, the film is reused as the ultraviolet-permeable film (A1) as the base material.

FIG. 3 is a schematic diagram showing a manufacturing process employing an example of a coating method for applying a photoreactive composition to a heavy release surface side of an ultraviolet-permeable film having a large release force. The ultraviolet-transmissive film (A2) 15 fed from the base material feeding roll 1 is first arranged such that the light release surface side is laminated on the photoreactive composition layer 14, and after the irradiation step, the roll 8 , 8, peeled off from the pressure-sensitive adhesive layer and inverted through 9, 10, 11, 7, etc.
As a UV-transparent film (A1) as a substrate, the photoreactive composition 3 was applied to the heavy release surface side of the coating rolls 2 and 2.
Is applied.

FIG. 4 is a schematic view showing a manufacturing process employing another example of a coating method for applying a photoreactive composition to a heavy release surface side of an ultraviolet ray permeable film having a large release force. After peeling off the ultraviolet-permeable film (A2) from the pressure-sensitive adhesive layer,
In FIG. 3, the light is inverted through the lower side of the ultraviolet irradiation device 4, whereas in FIG. In any case, after the reversal, the film is reused as the ultraviolet-permeable film (A1) as the base material. Thus, according to the production method of the present invention, utilizing the difference in the peel force between the front and back of one ultraviolet-transparent film, first, using the light release surface side as a release film,
After the peeling, the film is inverted and the heavy peeling surface side is used as a base material, so that there is no need to dispose of the used peeling film as in the related art.

As the coating rolls 2 and 2, a coating roll such as a comma head can be used. In the ultraviolet irradiation step, a cooling device such as a cooling roll or cooling water passing device may be installed in the ultraviolet irradiation zone. Since the photoreactive composition layer is in a state where both surfaces are laminated with an ultraviolet ray permeable film in the ultraviolet ray irradiation zone, the polymerization reaction does not occur due to no inhibition of polymerization by oxygen and no need to inert the atmosphere. In the ultraviolet irradiation step, the photoreactive composition undergoes a polymerization reaction (photocuring) to form an adhesive layer. The ultraviolet irradiation device is usually composed of a plurality of lamps. This ultraviolet irradiation device may be disposed on either the light release surface side or the heavy release surface side of the ultraviolet light transmitting film, and may be disposed on both sides if necessary. After the irradiation step, the ultraviolet-transmissive film (A2) that has been in contact with the pressure-sensitive adhesive layer on the light release surface side is easily released because the release force is smaller than the heavy release surface side.

The ultraviolet-permeable film used in the present invention has a peeling force (releasability or surface energy) on both sides.
However, the film is not particularly limited as long as it is a film that can transmit ultraviolet rays. Examples of the film include polyolefins such as polyethylene (PE) and polypropylene (PP); polyesters such as polyethylene terephthalate (PET); polyamides such as nylon 6, nylon 66, and nylon 6/66;
A film (including a sheet) of a thermoplastic resin having low ultraviolet absorption such as C) is preferable. These films may be multilayer films.

In order to form a surface having a small peeling force (lightly peeled surface), there is a method of performing a peeling treatment such as a silicone treatment. In order to form a surface having a large peeling force (heavy peeling surface), for example, there is a method of performing corona treatment. By appropriately combining these treatments, it is possible to prepare an ultraviolet-transmissive film having relatively different peeling forces on the front and back. Further, a multilayer film composed of a plurality of films having different surface energies may be used. More specifically, for example, a PET film subjected to single-sided peeling treatment, a PET film subjected to a peeling treatment with different peeling forces on the front and back, a PP film subjected to single-sided peeling treatment, a PP film subjected to a peeling treatment with different peeling forces on the front and back, a single-sided corona treated PP film,
Surface-corona-treated / backside-peeled PP film, single-sided-peeled PE film, front- and back-sided PE-treated peeling films with different peeling forces, single-sided corona-treated PE film, surface-corona-treated / backside-peeled PE film,
Examples thereof include a multilayer film formed by co-extrusion.
Among these, for example, when using a film subjected to a release treatment having a different release force on the front and back, the obtained pressure-sensitive adhesive sheet can be used as a double-sided pressure-sensitive adhesive sheet by easily peeling the base film at the time of use. .

The difference in the peeling force between the front and back of the ultraviolet ray permeable film is relative, but after the ultraviolet irradiation step,
By utilizing the difference in the peeling force between the two, there is a difference in the peeling force enough to peel off only the film on the lightly peeling surface side from the adhesive layer, leaving the film and the adhesive layer on the heavy peeling surface side. is necessary. Such a difference in peeling force can be easily set by performing the above-described various processes. Further, those skilled in the art can determine the preferable degree of the difference in the peeling force and the degree of the various treatments by a simple experiment. The thickness, width, and the like of the ultraviolet light transmitting film can be appropriately determined as needed.

The photoreactive composition used in the present invention is usually a composition containing an acrylate monomer, a vinyl monomer copolymerizable therewith, a photoinitiator and the like.
As the acrylate-based monomer, an alkyl (meth) acrylate having 1 to 14 carbon atoms in the alkyl group is generally used. Specific examples include n-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, isononyl (meth) acrylate, and the like.

Examples of the copolymerizable vinyl monomer include:
For example, vinyl acetate, N-vinylpyrrolidone, acrylic acid, itaconic acid, maleic acid, maleic anhydride, acrylamide, 2-hydroxypropyl acrylate, glycidyl methacrylate, carboxyethyl acrylate, cyclohexyl acrylate, isobornyl acrylate, tetrahydrofurfuryl acrylate And polyethylene glycol acrylate. These vinyl monomers are generally used in a range of 0 to 40% by weight based on all monomers. The acrylate monomer and the copolymerizable vinyl monomer can be used alone or in combination of two or more. In addition, a combination of these monomers can be selected in consideration of photopolymerization, volatility, interfacial adhesion, viscosity, and the like.

Examples of the photo initiator include 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2
-Methyl-1-phenyl-propan-1-one, 1-
(4-Isopropylphenyl) -2-hydroxy-2-
Methylpropan-1-one, 4- (2-hydroxyethoxy) phenyl (2-hydroxy-2-propyl) ketone, acetophenone, methoxyacetophenone, 2,3
-Dimethoxyacetophenone, 2,2-dimethoxy-2
-Phenylacetophenone, α-hydroxy-α, α '
-Dimethyl-acetophenone, p-dimethylaminoacetophenone, p-dimethylaminopropiophenone, benzophenone, 2-chlorobenzopheno, Michler's ketone, benzyl, benzoin, benzoin methyl ether, benzoinisopropyl ether, benzyldimethyl ketal, halogenated ketone , Acylphosphinoxide, acylphosphonate and the like.
These photoinitiators are generally used in a proportion of 0.1 to 5 parts by weight based on 100 parts by weight of the monomer component.

The photoreactive composition can be thickened to provide viscoelasticity suitable for coating. As a method of thickening, a method of adding a thickener such as a thermoplastic resin or silica, a method of compounding a photopolymerizable oligomer, a method of photopolymerizing a part of the photoreactive composition by ultraviolet irradiation in advance,
A method in which these are combined is exemplified. Further, if necessary, commonly used components such as a polyfunctional monomer, a tackifier resin, a chain transfer agent, a pigment, a filler, an extender, and a thixotropic agent may be added to the photoreactive composition. The coating thickness of the photoreactive composition can be appropriately selected according to the purpose of use, and is not particularly limited.
000 μm, preferably about 10 to 1000 μm. The light source used in the present invention is not particularly limited as long as it is a device that generates ultraviolet light.
Xenon lamps, mercury xenon lamps, high-pressure mercury lamps, metal halide lamps, medium-pressure mercury lamps, low-pressure mercury lamps, chemical lamps, germicidal lamps, fluorescent lamps for health rays, black lamps, excimer lasers, and the like can be given. One or two or more of these light sources may be combined.

[0021]

The present invention will now be described more specifically with reference to examples and comparative examples. In the following example,
“Parts” means “parts by weight”. [Example 1] Paper passing method: FIG. Film: PET film with a thickness of 38 μm, which has been silicone-treated on one side. Light source: 5 high-pressure mercury lamps of 3 kW in parallel (1 m interval) Web speed: 30 m / min Coating thickness: 30 μm Photoreactive composition: mixture of the following components 2-ethylhexyl Acrylate 75 parts Cyclohexyl acrylate 10 parts N-vinylpyrrolidone 5 parts Acrylic acid 5 parts Hydrophobic silica 5 parts 1-dodecyl mercaptan 0.005 parts 1-hydroxycyclohexyl phenyl ketone 0.3 parts Manufacture of an adhesive sheet under the above conditions. As a result, the pressure-sensitive adhesive sheet could be produced without any volatilization of the monomer and no contamination of the equipment due to the volatilization, and no wasteful film was produced.

[Example 2] Paper passing method: FIG. Film: 50 μm thick PP film treated with corona on one side Light source: 50 20W chemical lamps arranged in parallel (30 cm interval) Web speed: 10 m / min Coating thickness: 30 μm Photoreactive composition: mixed solution of the following components: isononyl acrylate 70 parts Cyclohexyl acrylate 15 parts N-vinylpyrrolidone 5 parts Maleic anhydride 5 parts Butyl acrylate polymer (molecular weight 300,000) 5 parts 1-dodecyl mercaptan 0.01 parts 2-hydroxycyclohexyl phenyl ketone 0.3 parts Adhesion under the above conditions When the sheet was produced, the pressure-sensitive adhesive sheet could be produced without any volatilization of the monomer and no contamination of the equipment due to the volatilization, and no wasteful film was produced.

[Example 3] Paper passing method: FIG. Film: 50 μm-thick PE film subjected to surface corona treatment and backside peeling treatment Light source: 50 parallel 20 W black lamps (30 cm interval) Web speed: 10 m / min Coating thickness: 30 μm Photoreactive composition: mixture of the following components The solution was previously irradiated with an 8W chemical lamp for 50 seconds to increase the viscosity (2000 mPa · s). Isononyl acrylate 70 parts Cyclohexyl acrylate 15 parts 2-hydroxypropyl acrylate 5 parts Acrylic acid 5 parts 1-dodecyl mercaptan 0.01 Part 3-Hydroxycyclohexyl phenyl ketone 0.3 part When the pressure-sensitive adhesive sheet was manufactured under the above conditions, there was no volatilization of the monomer and no contamination of the equipment due to it, and no wasteful film was produced. Thus, an adhesive sheet could be manufactured.

Example 4 Paper Passing Method: FIG. Film: PET film with a thickness of 38 μm that has been peeled off on one side. Light source: 30 20 W chemical lamps in parallel (30 cm intervals) followed by 2 3 kW high-pressure mercury lamps in parallel (1 m intervals) Web speed: 20 m / min Coating thickness: 30 μm photo-reactive composition: A solution in which a mixture of the following components was previously irradiated with an 8 W chemical lamp for 55 seconds to increase the viscosity (1500 mPa · s): isononyl acrylate 70 parts isobonyl acrylate 15 parts vinyl acetate 5 parts anhydrous Maleic acid 5 parts 1-dodecyl mercaptan 0.01 parts 4-hydroxycyclohexyl phenyl ketone 0.3 parts When the pressure-sensitive adhesive sheet was produced under the above conditions, there was no volatilization of the monomer and no contamination of the equipment due to it. In addition, the adhesive sheet could be manufactured without any wasted film.

Example 5 Paper Passing Method: FIG. Film: PET film of 38 μm thickness with different peeling treatments on both sides Light source: 5 high-pressure mercury lamps of 3 kW in parallel (1 m interval) Web speed: 12 m / min Coating thickness: 100 μm Photoreactive composition: mixture of the following components 2 -Ethylhexyl acrylate 75 parts Cyclohexyl acrylate 10 parts N-vinylpyrrolidone 5 parts Acrylic acid 5 parts Hydrophobized silica 5 parts 1,6-hexanediol diacrylate 0.4 parts 1-dodecylmercaptan 0.005 parts 5-hydroxycyclohexyl phenyl ketone 0.1 parts When the pressure-sensitive adhesive sheet is manufactured under the above conditions, the pressure-sensitive adhesive sheet is manufactured without any volatilization of the monomer and no contamination of the equipment due to the volatilization, and no wasteful film is produced. Was completed. This pressure-sensitive adhesive sheet can be used as a double-sided pressure-sensitive adhesive sheet by peeling the base film.

Comparative Example 1 Paper Passing Method: FIG. Substrate: 38 μm thick PET film treated with silicone on one side Release material: 38 μm thick PET film treated with silicone on one side Light source: 5 3 kW high-pressure mercury lamps arranged in parallel (1 m interval) Web speed: 30 m / min Coating thickness: 30 μm Photoreaction Hydrophobic composition: A mixture of the following components: 2-ethylhexyl acrylate 75 parts Cyclohexyl acrylate 10 parts N-vinylpyrrolidone 5 parts Acrylic acid 5 parts Hydrophobized silica 5 parts 1-dodecyl mercaptan 0.005 parts 6-hydroxycyclohexyl phenyl ketone 0 .3 parts When the pressure-sensitive adhesive sheet was manufactured under the above conditions, the pressure-sensitive adhesive sheet could be prepared without volatilization of the monomer and contamination of the equipment due to the volatilization, but the PET film as the release material was repeatedly used three times. After use, the silicone is desorbed and the fourth Peeling from the adhesive layer becomes difficult in use, also is a slight crease occurs by heat or reaction heat from the light source can not be reused, was only discarded.

[0027]

According to the present invention, there is provided a method for producing a photocurable pressure-sensitive adhesive tape in which various problems associated with disposal of a release film are solved, and characteristics such as pollution-free, energy-saving and resource-saving are further improved. .

[Brief description of the drawings]

FIG. 1 is a process chart showing one embodiment of a manufacturing method of the present invention.

FIG. 2 is a process chart showing another embodiment of the manufacturing method of the present invention.

FIG. 3 is a process chart showing another embodiment of the manufacturing method of the present invention.

FIG. 4 is a process chart showing another embodiment of the manufacturing method of the present invention.

FIG. 5 is a process chart showing an example of a conventional manufacturing method.

[Explanation of symbols]

 1: substrate feeding roll 2: coating roll 3: photoreactive composition 4: UV irradiation device 5: adhesive sheet winding roll 6: roll 7: roll 8: roll 9: roll 10: roll 11: roll 12: Roll 13: UV-permeable film 14: Adhesive layer 51: Release material feeding roll 52: Coating roll 53: Substrate feeding roll 54: Photoreactive composition 55: Irradiation device 56: Release material winding roll 57: Adhesion Sheet take-up roll 58: Roll 59: Roll 60: Roll 61: Substrate 62: Release film 63: Photoreactive composition layer

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4J004 AA10 AB07 CA04 CA05 CA06 CC04 CD06 CD08 DA02 DA03 DA04 DB02 GA01 4J040 FA062 FA072 FA102 FA141 FA142 FA182 JA09 JB08 JB09 KA13 PA32 PA42 QA09 QB04

Claims (1)

[Claims] 1. A photoreactive composition layer is formed between a substrate and a release film, and in the process of transporting the photoreactive composition layer, the photoreactive composition layer is irradiated with ultraviolet light to polymerize the photoreactive composition. Forming a pressure-sensitive adhesive layer, and then peeling the release film from the pressure-sensitive adhesive layer. In the method for producing a pressure-sensitive adhesive sheet, (1) both the substrate and the release film have a relative release force between the front surface and the back surface. Using different UV-permeable films (A)
(2) forming a photoreactive composition layer between the heavy release surface of the ultraviolet transparent film (A1) having a large release force and the light release surface of the ultraviolet transparent film (A2) having a small release force;
(3) In the process of transporting this, ultraviolet light is irradiated through at least one of the ultraviolet light transmitting films to polymerize the photoreactive composition to form a pressure-sensitive adhesive layer,
(4) The ultraviolet-transmissive film (A2) is peeled off from the pressure-sensitive adhesive layer, and (5) the peeled-off ultraviolet-transparent film (A2) is inverted to form an ultraviolet-permeable film (A1).
A method for producing a pressure-sensitive adhesive sheet, wherein the pressure-sensitive adhesive sheet is reused.