JPH02252780A - Adhesive sheet manufacturing method - Google Patents

Abstract

PURPOSE:To obtain a self-adhesive sheet which shows no clouding in the self-adhesive agent and has no flaw on a surfacing material by applying an ionizing radiation-curable self-adhesive compsn. to a release sheet, laminating the resulting layer of the self-adhesive compsn. with a surfacing material, and irradiating the resulting laminate with an ionizing radiation to convert the self-adhesive compsn. layer into the self-adhesive. CONSTITUTION:An ionizing radiation-curable self-adhesive compsn. which is polymerizable and/or crosslinkable by irradiation with an ionizing radiation (e.g. electron beams) to convert into a self-adhesive and which contains pref. at least one compd. selected from the group consisting of an acrylic resin, an acrylic prepolymer, and an acrylic monomer is applied to a release sheet (e.g. polyethylene-laminated paper coated with a silicone release agent) to form a self-adhesive compsn. layer, with which a surfacing material (e.g. a polyethylene terephthalate film) is laminated. The resulting laminate is irradiated with an ionic radiation to convert the self-adhesive agent compsn. into a self-adhesive.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for producing a pressure-sensitive adhesive sheet, and particularly relates to a method for producing a pressure-sensitive adhesive sheet that does not cause damage to the surface substrate and has a highly transparent adhesive. .

``Prior Art'' Adhesive sheets are used in a very wide range of applications, including commercial, office, and household uses, as labels, stickers, sticker patches, and the like. The general structure of this pressure-sensitive adhesive sheet is such that the pressure-sensitive adhesive layer is sandwiched between a surface base material and a release sheet.

Surface materials include paper, cloth/nonwoven fabrics, and films.

Metal foils, etc. are used, and release sheets include high-density base paper such as glassine paper, clay coated paper, polyethylene laminated paper, high-density base paper such as glassine paper laminated with polyethylene, and release sheets such as films. , those coated with a release agent such as a silicon compound or a fluorine compound are used. As adhesives, solvent-type adhesives, emulsion-type adhesives, hot-melt-type adhesives, etc. are used, but each of them has drawbacks as described below.

In other words, solvent-based adhesives use large amounts of flammable and highly toxic solvents, which poses the risk of fire and explosion, as well as health and safety issues. It takes time and the water resistance of the adhesive is poor.

In addition, hot-melt adhesives generally require a weight-average molecular weight of several tens to hundreds of blades in order to exhibit sufficient physical properties. It is not possible to obtain a pressure-sensitive adhesive sheet by high-speed operation in large quantities, and the operability of production is poor.

In order to improve the above-mentioned drawbacks of adhesives, ionizing radiation-curable adhesives have been studied.

For example, acrylic resin is diluted with an acrylic monomer to adjust the viscosity so that it can be coated at relatively low temperatures, and then polymerized and/or crosslinked by irradiation with ionizing radiation to obtain adhesive and cohesive strength as an adhesive. A method is proposed.

However, when applying an ionizing radiation-curable adhesive composition to a surface substrate, there are the following problems.

In other words, since ionizing radiation-curable adhesives contain almost no solvent or water and have a very high solids content, the amount of coating fluid used during application is much smaller than that of solvent-based or emulsigin-based adhesives, and the coater head is difficult to apply. It comes in close proximity to the surface base material and is likely to damage the first surface base material.

Such scratches may be caused by direct contact with the coater head.

This is thought to be caused by foreign matter being inserted between the coater head and the surface base material. As a result, scratches on the surface substrate cause unevenness to occur on the surface opposite to the surface to which the ionizing radiation-curable adhesive composition is applied (front side), resulting in poor printability and uneven surface gloss. When applied to the vapor-deposited surface of a metal-deposited film, scratches may cause the deposit to fall off, and if the surface substrate is a transparent film, the scratches may impair transparency and aesthetics.

Therefore, when manufacturing a pressure-sensitive adhesive sheet by applying an ionizing radiation-curable adhesive composition to a surface substrate, laminating a release sheet and then irradiating it with ionizing radiation, or applying an ionizing radiation-curable adhesive composition to a surface substrate. When producing a t-adhesive sheet by coating a t-adhesive composition and laminating a release sheet by directly irradiating the ionizing radiation-curable adhesive composition layer with ionizing radiation, there is an inconvenience that the surface substrate is easily scratched. Occur.

In addition, when forming an adhesive sheet by directly irradiating the ionizing radiation-curable adhesive composition layer with ionizing radiation after applying the ionizing radiation-curable adhesive composition with a coater, the following problems may occur. Occur.

When forming an adhesive sheet by applying an ionizing radiation-curable adhesive composition to a release sheet, irradiating the ionizing radiation-curing adhesive composition layer with ionizing radiation, and bonding one surface base material to the other, the surface base material The problem was that the adhesion between the material and the adhesive deteriorated.

In addition, when producing an adhesive sheet by applying an ionizing radiation-curable adhesive composition directly to the surface substrate, irradiating it with ionizing radiation, and laminating a release sheet, in addition to the scratches on the surface substrate described above, If the release sheet is not smooth, clouding will occur on the adhesive surface.

The cloudiness that appears when an ionizing radiation-curable adhesive composition is directly irradiated with ionizing radiation ranges from 10 μm to 30 μm in diameter.
Tens to hundreds of minute circular opaque dots of about 0 μm gather together to form an elliptical or rectangular group. 2 Usually, one to several dozen dots are formed on a 7 mm square adhesive surface. Such groups are observed and cause a significant decrease in the transparency of the adhesive.

"Problems to be Solved by the Invention" The present invention solves the above-mentioned problems in the method of manufacturing a pressure-sensitive adhesive sheet using an ionizing radiation-curable pressure-sensitive adhesive composition, and eliminates clouding of the pressure-sensitive adhesive and prevents damage to the surface substrate. The purpose of the present invention is to provide a method for manufacturing a pressure-sensitive adhesive sheet.

"Means for Solving the Problems" The present invention involves coating a release sheet with an ionizing radiation-curing adhesive composition that is polymerized and/or crosslinked to form an adhesive by irradiation with ionizing radiation, and applying a surface layer on the coating layer. This method of producing a pressure-sensitive adhesive sheet is characterized in that the ionizing radiation-curable pressure-sensitive adhesive composition is made into a pressure-sensitive adhesive by irradiating a laminate obtained by stacking base materials with ionizing radiation.

"Function" Various apparatuses such as a gui coater, a roll coater, a gravure coater, etc. are used as appropriate to apply the ionizing radiation curable pressure-sensitive adhesive composition to the release sheet before curing. In the present invention, since the above-mentioned pressure-sensitive adhesive composition is first applied to a release sheet before curing, even if the release sheet is damaged during application,
There is no damage to the surface material of the adhesive sheet. Therefore, problems such as unevenness occurring on the surface base material and impairing printability and surface gloss can be solved.

In order to adjust the viscosity of the above-mentioned pressure-sensitive adhesive composition, if heating is required, a heating device can be appropriately used in various coating devices. The dry coating amount of the adhesive composition is 3g/nf to 100
It is preferable to adjust within a range of about 5g/rrf, especially 5
About g/po to 70 g/rri is desirable.

Next, a surface base material is laminated and bonded onto the pressure-sensitive adhesive composition layer before curing. By subsequently irradiating the adhesive composition with ionizing radiation and converting the adhesive composition into an adhesive, a cloud-free adhesive layer can be obtained.

As the ionizing radiation, ultraviolet cotton, electron beams, T-rays, etc. are used, and electron beams are particularly preferred in terms of transparency, energy efficiency, and ease of handling.

The pressure-sensitive adhesive sheet prepared in this way does not cause any damage to the surface base material, and has good adhesion between the surface base material and the adhesive.

It has a highly transparent adhesive layer with no clouding.

Although not particularly limited, in the present invention, ionizing radiation is preferably irradiated from the surface substrate side.

Even in this case, the release sheet is irradiated with ionizing radiation, and the decomposition of the release agent tends to increase the release force of the adhesive sheet. Depending on the application, heavy release force may be inconvenient, but the following method can increase the release force. can be made lighter.

That is, by peeling off the release sheet of the pressure-sensitive adhesive sheet obtained by the above method from the adhesive and bonding the release sheet together again, an easily peelable pressure-sensitive adhesive sheet can be obtained.

This process may be performed, for example, by applying an adhesive to a release sheet with a coater, bonding the surface substrate, and irradiating the adhesive sheet with ionizing radiation, and then performing it in-line before winding up the adhesive sheet. It may be performed off-line after winding up after radiation irradiation.

The release sheet is not particularly limited, and various commercially available release sheets can be used. For example, using general paper such as high-quality paper, medium-quality paper, and kraft paper, or those made by passing these through a supercalender to increase its smoothness, use a polylaminate made by laminating polyethylene or polypropylene as a release base, and then apply silicone compounds or fluorine to this. Products coated with a release agent such as a chemical compound; High-density base paper such as glassine paper coated with a release agent; High-density base paper such as glassine paper laminated with polyethylene or polypropylene and coated with a release agent; Clay-coated paper coated with a release agent; examples include films made of polyethylene, polypropylene, polyester, polyamide, polyimide, polyvinyl chloride, etc. alone or in a laminate coated with a release agent.Also, release sheets. The surface opposite to the surface to which the release agent is applied is laminated with polyethylene or polypropylene, or various resins such as vinylidene chloride resin and acrylic resin are applied to make it waterproof and prevent curling. can also be used.

In addition, if special requirements are placed on the smoothness and transparency of the adhesive, the smoothness of the surface of the release sheet in contact with the ionizing radiation-curable adhesive composition coating layer may be determined by an air micrometer smoothness test (
It is preferably 5.0cmHg or less, more preferably 2.0cmHg or less, most preferably 1.0cmHg as measured by a smoother of JTAPP I, No. 5).
Use one with Hg or less.

Since the adhesive sheet is peeled off from the release sheet and applied to the adherend, the smoothness of the adhesive surface that sticks to the adherend is affected by the smoothness of the release sheet.

Smoothness of release sheet by smoother is 5.0cmH
If it exceeds g, the smoothness of the adhesive layer will be poor, and sufficient adhesion to the adherend may not be obtained, resulting in poor adhesion, or air bubbles may form between the adhesive surface and the adherend, resulting in poor adhesion and poor appearance. This may cause negative effects such as poor performance.

Furthermore, when the surface substrate is a transparent film, the adhesive layer is also particularly required to be transparent. However, if the smoothness of the release sheet exceeds 5.0 cmHg, the smoothness of the adhesive layer will also deteriorate, causing light scattering and loss of transparency, and as mentioned above, it may not be suitable for attachment to smooth surfaces. Deteriorate. When a transparent film is used as a surface base material and is pasted onto a printed matter, etc., and the surface of the adherend is viewed through the surface base film and adhesive, an adhesive sheet made by pasting an adhesive on the printed surface of the surface base material is used. When adhering to a transparent adherend such as glass or transparent plastic, if the printed matter of the surface base material is to be viewed through the adherend and the adhesive, the adhesive layer particularly requires smoothness and accompanying transparency. That is, the smoothness of the release sheet is 5. Ocm
If it exceeds Hg, the appearance may deteriorate due to light scattering and inclusion of air bubbles, and the image of the printed matter viewed through the adhesive may become somewhat unclear.

Surface substrates include medium-quality paper, high-quality paper, and coated paper.

Fibrous substrates including cast paper, impregnated paper, cloth, non-woven fabric, cellophane, polyethylene, polypropylene, polyester, polyamide, polyimide.

Film base materials including polyvinyl chloride, polyvinylidene fluoride, cellulose acetate, polycarbonate, etc., processed products including vapor deposited products, coated products, and laminates thereof, metal foils, etc. can be used.

The ionizing radiation-curable adhesive composition that is turned into an adhesive by irradiation with ionizing radiation contains at least one of a rubber resin, an acrylic resin, an acrylic prepolymer, an acrylic monomer, etc. as a main component. can be,
Preferably, a crosslinking agent having a radically polymerizable double bond is added.

Examples of rubber-based resins include natural rubber, isoprene rubber,
Styrene-butadiene block copolymer.

Styrene/isoprene block copolymer, butyl rubber,
Examples include styrene/ethylene/butene block copolymer, polyisobutylene, polyvinyl isobutyl ether, chloroprene rubber, and nitrile rubber.

These rubber-based resins include natural resins such as rosin.

Modified rosin, rosin and derivatives of modified rosin, polyterpene resin, modified terpene, aliphatic hydrocarbon phase, cyclopentadiene resin, aromatic petroleum resin, phenolic resin, alkyl-phenol-acetylene resin,
Tackifier resins, various plasticizers, anti-aging agents, stabilizers, including styrene resins, xylene resins, coumaron indene resins, vinyltoluene-α-methylstyrene copolymers, etc.

Softeners such as oil, fillers, stabilizers, pigments, colorants, etc. can be added as necessary. These can also be used in combination of two or more types as required.

Ionizing radiation-curable adhesive compositions containing acrylic resins, prepolymers, or monomers (hereinafter simply referred to as acrylic resins) compared to rubber-based resins have excellent weather resistance and are suitable for finishing when processing adhesive labels. Since it is also good, it is more preferably used.

The acrylic resin is not particularly limited, and gynomers, copolymers, etc., which are almost the same monomers as those used in general solvent-type acrylic adhesives and emulsion-type acrylic adhesives, can be used. for example.

Vinyl monomers having an alkyl group, vinyl monomers having a hydroxyl group, vinyl monomers having an epoxy group, vinyl monomers having an alkoxyl group, vinyl monomers having an ethylene oxide group, vinyl monomers having an amino group, vinyl monomers having an amide group,
Vinyl monomers having a carboxyl group, vinyl monomers having a halogen atom, vinyl monomers having a phosphoric acid group, vinyl monomers having a sulfonic acid group, vinyl monomers having a silane group, vinyl monomers having a urethane group, vinyl monomers having a phenyl group. -, a vinyl monomer having a benzyl group, a vinyl monomer having a tetrahydrofurfuryl group, and other copolymerizable heptamers.

As a vinyl monomer having an alkyl group.

Methyl (meth)acrylate, ethyl (meth)acrylate, isopropyl (meth)acrylate lauryl (meth)acrylate, stearyl (meth)acrylate butyl (meth)acrylate.

Hexyl (meth)acrylate, cyclohexyl (meth)acrylate 2-ethylhexyl (meth)acrylateisoamyl (meth)acrylate, isooctyl (
Examples include meth)acrylate, n-octyl(meth)acrylate, dodecyl(meth)acrylate, isobutyl(meth)acrylate, and the like.

As a vinyl monomer having a hydroxyl group, 2-
Hydroxyethyl (meth)acrylate.

2-hydroxypropyl (meth)acrylate 2-hydroxybutyl (meth)acrylate, 3-chloro-2-
Examples include hydroxy (meth)acrylate.

As a nil monomer with an epoxy group.

Glycidyl (meth)acrylate, methylglycidyl (
Examples include meth)acrylate.

Examples of the vinyl monomer having an alkoxyl group include methoxyethyl (meth)acrylate, ethoxyethyl (meth)acrylate, butoxyethyl (meth)acrylate, and phenoxyethyl (meth)acrylate.

As a vinyl monomer having an ethylene oxide group,
Diethylene glycol (meth)acrylate, methoxydiethylene glycol (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, phenoxydiethylene glycol (meth)acrylate, phenoxypolyethylene glycol (meth)acrylate, and the like.

Examples of vinyl monomers having an amino group include dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, N-tert-butylaminoethyl (meth)acrylate, methacryloyloxyethyltrimethylammonium chloride (meth)acrylate, and the like. .

As a nil monomer having an amide group, (meth)
Acrylamide, N-methylol (meth)acrylamide, N-methoxymethyl (meth)acrylamide, N-
Examples include butoxymethyl (meth)acrylamide, N,N'-methylenebis(meth)acrylamide, and the like.

Examples of vinyl monomers 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, and 2-methacryloyl Examples include oxyethyl hexahydrophthalic acid.

As a vinyl monomer containing a halogen atom.

Trifluoroethyl (meth)acrylate, bentadecafluoroquictyl (meth)acrylate 2-chloroethyl (meth)acrylate, 2゜3 dibromopropyl (
Meth)acrylate Tribromphenyl (meth)acrylate and the like can be mentioned.

As a vinyl monomer having a phosphoric acid group, 2-methacryloyloxyethyl diphenyl phosphate (meth)
Examples include acrylate, trimethacryloyloxyethyl phosphate, triacryloyloxyethyl phosphate, and the like.

As a vinyl monomer having a sulfonic acid group.

Sodium sulfopropyl (meth)acrylate Sodium 2-sulfoethyl (meth)acrylate, Sodium vinylsulfonate, Sodium styrenesulfonate, Sodium 2-acrylamide-2-methylpropanesulfonate,
Examples include sodium 3-allyloxy-2-hydroxypropanesulfonate.

Examples of the vinyl monomer having a silane group include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris(β-methoxyethoxy)silane, vinyltriacetylsilane, methacryloyloxypropyltrimethoxysilane, and the like.

As a vinyl monomer having a urethane group.

Examples include urethane (meth)acrylate.

As a vinyl monomer having a phenyl group.

Examples include phenyl (meth)acrylate, p-tert-butylphenyl (meth)acrylate, and 0-biphenyl (meth)acrylate.

As a vinyl monomer having a benzyl group.

Examples include benzyl (meth)acrylate.

Examples of the vinyl monomer having a tetrahydrofurfuryl group include tetrahydrofurfuryl (meth)acrylate.

Other copolymerizable monomers include styrene, chlorostyrene, α-methylstyrene, vinyltoluene, vinyl chloride, vinyl acetate, vinyl propionate, and Veov.
alO (Shell Chemical Co., Ltd., vinyl alkylate compound)
, acrylonitrile.

Examples include vinylpyridine.

In addition, polyfunctional vinyl monomers can be copolymerized within a range that does not impede the coating suitability of the ionizing radiation-curable adhesive before curing, and the resin contains Na., K., Li"Mg", Ca"°, and Z.
ionic crosslinking agent containing n'', etc.

Epoxy resin, melamine-formaldehyde resin.

Hardening agents such as amino-formaldehyde resins, urea resins, diisocyanates, etc. can also be added.

Examples of polyfunctional vinyl monomers include ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate-1-, and triethylene glycol di(meth)acrylate.
Acrylate, dipropylene glycol di(meth)acrylate, 1.3-7' ethylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate.

tetramethylolmethanetetra(meth)acrylate,
Examples include divinylbenzene, N,N'-methylenebisacrylamide, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, and the like.

For the purpose of improving hardenability due to ionizing radiation.

A functional group sensitive to ionizing radiation, such as an ethylenically unsaturated bond, may be introduced into the resin.

Examples of the ionic crosslinking agent include zinc acetate, magnesium acetate, calcium acetate, and the like.

In order to improve the physical properties of these acrylic resins, various additives, such as natural resins such as rosin, etc., are added, as in the case of rubber resins.
Modified rosin, rosin and modified rosin derivatives, polyterpene resins, terpene modified products, aliphatic hydrocarbon resins,
Cyclopentadiene resin, aromatic petroleum resin, phenolic resin, alkyl-phenol-acetylene resin, styrene resin, xylene resin, coumaron indene resin.

Add tackifying resins such as vinyltoluene-α-methylstyrene copolymer ring, various plasticizers, anti-aging agents, stabilizers, softeners such as oil, fillers, stabilizers, pigments, 9 colorants, etc. as necessary. can be added.

These can also be used in combination of two or more types as required.

There are a large number of monomers that can be copolymerized with acrylic resins, and there are also a large number of additives that can be used to improve the physical properties and stability of adhesives.The monomers and additives that can be used are not limited to those mentioned above. .

If the weight average molecular weight of the acrylic resin is smaller than 1Xl0', it may not be possible to obtain a product with sufficient cohesive force and adhesive strength even if it is polymerized and/or crosslinked by irradiation with ionizing radiation, and 6X]O' If it is larger, it may not be possible to lower the viscosity to a coatable level even if heated, so the weight average molecular weight of the resin body is preferably lXl0.
'~6x105, more preferably 5X10''~5X10
It is desirable to adjust within a range of about S.

The above acrylic resins are produced by bulk polymerization or solution polymerization.

It can be synthesized by any method such as a suspension polymerization method or an emulsion method, and if necessary, an ionizing radiation functional group can be introduced therein, and further, a crosslinking agent 2-reactive monomer, various additives, etc. can be added as necessary. When adding a crosslinking agent, the viscosity of the coating liquid may increase over time depending on the properties of the resin and crosslinking agent.
In such cases, a crosslinking agent may be added just before coating. Note that these operations may be performed by heating to lower the viscosity of the resin, if necessary.

In addition, a crosslinking agent having a radically polymerizable double bond may be mixed in order to improve the coating suitability of the aforementioned rubber resin or acrylic resin and to promote curing of the resin by polymerizing and/or crosslinking during irradiation with ionizing radiation. is preferred. The amount of the crosslinking agent having a radically polymerizable double bond is not necessarily limited, but is preferably about 0.5 to 100 parts by weight per 100 parts by weight of the acrylic resin and/or rubber resin. - The following prepolymers and monomers are exemplified as crosslinking agents that can be used.

(a) Aliphatic, alicyclic, araliphatic, aromatic di- to hexavalent polyhydric alcohols and polyalkylene glycols.
(meth)acrylate.

(b) Poly(meth)acrylate of a polyhydric alcohol in the form of an alkylene oxide added to an aliphatic, alicyclic, araliphatic, or aromatic di- to hexavalent polyhydric alcohol.

(C) Poly(meth)acryloyloxyalkyl phosphate ester.

(d) Polyester poly(meth)acrylate.

(e) Epoxy poly(meth)acrylate.

(f) Polyurethane poly(meth)acrylate.

(g) Polyamide poly(meth)acrylate.

(h) Polysiloxane poly(meth)acrylate.

(i) A vinyl-based or diene-based low polymer having a (meth)acryloyloxy group in a side chain and/or at a terminal.

(j) Examples include prepolymers of modified oligoester (meth)acrylates described in (a) to (i) above.

Also as a monomer.

(a) Carboxyl group-containing monomers represented by ethylenically unsaturated mono- or polycarboxylic acids, and carboxylic acid group-containing monomers such as their alkali metal salts, ammonium salts, and amine salts.

(b) An amide group-containing monomer represented by ethylenically unsaturated (meth)acrylamide or alkyl-substituted (meth)acrylamide, and vinyl lactams such as N-vinylpyrrolidone.

(c) Sulfonic acid group-containing monomers represented by aliphatic or aromatic vinyl sulfonic acids, and sulfonic acid group-containing monomers such as alkali metal salts, ammonium salts, and amine salts thereof.

(d) A hydroxyl group-containing monomer represented by ethylenically unsaturated ether.

(e) Dimethylaminoethyl (meth)acrylate-2
-Amino group-containing monomers such as vinylpyridine.

(f) Quaternary ammonium base-containing monomer.

(g) Alkyl esters of ethylenically unsaturated carboxylic acids.

(h) A nitrile group-containing monomer such as (meth)acrylonitrile.

(i) Styrene.

(j) Esters of ethylenically unsaturated alcohols such as vinyl acetate and (meth)allyl acetate.

(k) Mono(meth)acrylates of alkylene oxide addition polymers of compounds containing active hydrogen.

(1) An ester group-containing bifunctional monomer represented by a diester of a polybasic acid and an unsaturated alcohol.

(m) Bisacrylamides such as N,N-methylenebisacrylamide.

(0) Divinylbenzene, divinylethylene glycol, divinyl sulfone, divinyl ether.

Bifunctional monomers such as divinyl ketone.

(p) Ester-containing monomer represented by polyester of polycarboxylic acid and unsaturated alcohol.

(q) A polyfunctional monomer consisting of a polyester of an alkylene oxide addition polymer of a compound containing active hydrogen and (meth)acrylic acid.

(r) Polyfunctional unsaturated monomers such as trivinylbenzene.

etc., but of course the material is not limited to these, and various materials that can be crosslinked by irradiation with ionizing radiation can be used, and two or more types can also be used in combination.

The adhesive composition before curing has a viscosity of 50 cps when applied.
~200,000cps, more preferably 100cps
The viscosity of the coating liquid is preferably within the range of ~100,000 cps, and if necessary, the viscosity of the coating liquid can be adjusted within the above viscosity range by heating. If the viscosity is less than 50 cps, repellency may occur when applied on a release sheet and the coating may not be sufficiently wetted, and if the viscosity is 200,000 cps or more, the viscosity is high and coating suitability is poor, and it may not be possible to apply the coating to an appropriate thickness.

Example F The present invention will be described in more detail with reference to Examples below, but the present invention is of course not limited to these examples. In addition, the coating amount (9 parts), mixing ratio, etc. in the examples are all expressed in terms of solid content.

Example 1 A silicone release agent (trade name: KS-834, manufactured by Shin-Etsu Chemical) 1 was applied to a polyethylene laminate paper weighing 86 g/%.
00 parts by weight and catalyst (product name: PL-3゜Shin-Etsu Chemical)
A coating liquid consisting of 0.1 parts by weight was applied to give a dry weight of 0.5 g/bore and cured by heating at 110° C. for 90 seconds to obtain a release sheet. The smoothness of this release sheet using a smoother was 10.0 cmHg.

Electron beam curable acrylic adhesive (product name: X-585-
954M, manufactured by Seiden Chemical) 100 parts by weight at 130°C
Radical polymerizable 2 containing trifunctional acrylate monomer and urethane acrylate compound as main components
Crosslinking agent with type bond (Product name: X-585-955
M, made by Seiden Chemical Co., Ltd.) and 10 parts by weight of the resulting electron beam curable adhesive composition was placed on a release sheet with a weight of 20 parts by weight.
g/n (after coating with a die coater, a 50 μm thick polyethylene terephthalate film was laminated onto the electron beam curable adhesive surface. Irradiation amount 4Mr a
A pressure-sensitive adhesive sheet was prepared by performing the electron beam irradiation treatment in step d.

In the resulting pressure-sensitive adhesive sheet, no clouding of the pressure-sensitive adhesive was observed, there were no scratches on the surface base material, and the adhesiveness between the surface base material and the pressure-sensitive adhesive was high.

Example 2 Silicone release agent (trade name: KS-834, manufactured by Shin-Etsu Chemical) 100 weight on polyethylene laminated paper with polyethylene laminated on 125 g/r+ (high-quality paper supercalendered to improve smoothness) A coating solution consisting of 0.1 parts by weight of catalyst and catalyst (trade name: PL-3, manufactured by Shin-Etsu Chemical) was applied to a dry weight of 0.65 g/rri and cured by heating at 110°C for 90 seconds to form a release sheet. The smoothness of this release sheet by smoother was 4.
．． It was 5 cmHg.

Electron beam curable acrylic adhesive (product name: X585-9
54M, manufactured by Siden Chemical) was heated and melted at 130°C, and 10 parts by weight of a bridge W agent having a radically polymerizable type 2 bond (trade name: X-585-955M, manufactured by Siden Chemical) was mixed. The resulting electron beam curable adhesive composition was applied onto a release sheet using a Gui coater to a weight of 20 g/ryi, and then a 50 μm thick polyethylene terephthalate film was laminated onto the electron beam curable adhesive surface. . The obtained laminate was applied with an accelerating voltage of 17 cm from the surface base material side.
An adhesive sheet was prepared by performing electron beam irradiation treatment at 0 KV with an irradiation dose of 4 Mr ad.

In the resulting pressure-sensitive adhesive sheet, no clouding of the pressure-sensitive adhesive was observed, there were no scratches on the surface base material, and the adhesiveness between the surface base material and the pressure-sensitive adhesive was high. When this adhesive sheet was attached to glass, it was confirmed that there were fewer gaps than in Example 1 (and that the adhesive had higher smoothness than in Example 1).

Example 3 A silicone release agent (trade name: KS-834 manufactured by Shin-Etsu Chemical) 1 was applied to polyethylene-laminated glassine paper (trade name: KS-834 manufactured by Shin-Etsu Chemical), which was made by laminating polyethylene on glassine paper of 64 g/rrf.
00 parts by weight and catalyst (trade name 2PL-3, manufactured by Shin-Etsu Chemical) 0
．． The dry weight of the coating liquid consisting of 1 part by weight is 0.5 g/rrr.
The release sheet was coated and cured by heating at 110"C for 90 seconds to obtain a release sheet. The smoothness of this release sheet using a smoother was 1.7 cmHg.

Electron beam curable acrylic adhesive (product name: X585-9
100 parts by weight of 54M (manufactured by Saiden Chemical) were heated and melted at 130°C to obtain a crosslinking agent having a radically polymerizable type 2 bond (trade name: X-585-9, 55M, manufactured by Saiden Chemical) 10
After mixing the parts by weight and applying the obtained electron beam curable adhesive composition onto a release sheet using a Gui coater so that the weight becomes 20 g/rrr, a 50 μm thick polyethylene terephthalate film was coated with an electron beam curable adhesive composition. It was attached to the drug surface. The obtained laminate was applied with an accelerating voltage of 17 cm from the surface base material side.
An adhesive sheet was prepared by performing electron beam irradiation treatment at 0 KV and ffi4 Mrad.

In the resulting pressure-sensitive adhesive sheet, no clouding of the pressure-sensitive adhesive was observed, there were no scratches on the surface base material, and the adhesiveness between the surface base material and the pressure-sensitive adhesive was high. When this adhesive sheet was applied to glass, it was found that it adhered very neatly and that the adhesive surface was highly smooth.

Example 4 A polypropylene film with a thickness of 40 μm was coated with 100 parts by weight of a silicone release agent (trade name: KS-834, manufactured by Shin-Etsu Chemical) and 0.1 part by weight of a catalyst (trade name: PL-3, manufactured by Shin-Etsu Chemical). The coating liquid was applied to give a dry weight of 0.5 g/rri and cured by heating at 100"C for 90 seconds to obtain a release sheet. The smoothness of this release sheet using a smoother was 0.1 cmHg. .

Electron beam curable acrylic adhesive (product name: X585-9
54M, manufactured by Siden Chemical) was heated and melted at 130°C, and 10 parts by weight of a crosslinking agent having a radically polymerizable type 2 bond (trade name 2X-585-955M, manufactured by Siden Chemical) was mixed. The electron beam curable adhesive composition was coated onto a release sheet using a guicoater so that the weight was 15 g/rrf, and then a 20 μm thick polypropylene film was laminated onto the surface of the electron beam curable adhesive composition.

The obtained laminate was subjected to electron beam irradiation treatment from the surface substrate side at an acceleration voltage of 170 KV and a dose of 4 Mr ad to prepare a pressure-sensitive adhesive sheet.

In the resulting pressure-sensitive adhesive sheet, no clouding of the pressure-sensitive adhesive was observed, there were no scratches on the surface base material, and the adhesiveness between the surface base material and the pressure-sensitive adhesive was high. Furthermore, when this adhesive sheet was applied to glass, it was confirmed that it adhered very neatly without any gaps, and that the adhesive surface was highly smooth.

Example 5 A pressure-sensitive adhesive sheet was prepared in the same manner as in Example 4, and the release sheet was once peeled off from the pressure-sensitive adhesive sheet, and the sheets were bonded together again to form a pressure-sensitive adhesive sheet. The peeling force of this adhesive sheet is 15g
75cm and 70g/5 before re-bonding
It showed a value lower than cm.

Comparative Example 1 An electron beam curable adhesive composition was prepared in the same manner as in Example 1. 50μ polyethylene terephthalate film (
It was coated onto the surface substrate (surface substrate) using a guicoater to a weight of 20 g/rd, and was subjected to electron beam irradiation treatment at an acceleration voltage of 170 kV and a dose of 4 Mrad from the electron beam curable adhesive composition surface.

Next, a release sheet prepared in the same manner as in Example 1 was pasted together to produce an adhesive sheet.

The resulting pressure-sensitive adhesive sheet had scratches on the surface substrate, which were thought to have been caused by contact with the coater head, and cloudiness was observed on the pressure-sensitive adhesive surface, making it unsuitable for use as a pressure-sensitive adhesive sheet.

This cloudy image analysis device (product name: i DOT ANAL)
YZERD^2001. (manufactured by Kanzaki Paper Co., Ltd.), it was found that there were 180 opaque or translucent circular parts with a diameter of less than 113μ in a 7mm square.
114 opaque or translucent circular parts of 234 μm
It has been confirmed that there are The area ratio of this circular portion to the whole was 4.7%.

Comparative Example 2 An electron beam curable adhesive assembly prepared in the same manner as in Example 1 was applied to a release sheet prepared in the same manner as in Example 3 using a Gui coater so that the weight was 20 g/rrf. , from the electron beam curable adhesive composition side, acceleration voltage 170k
After performing electron beam irradiation treatment with a dose of 4 Mrad at V, 2
A pressure-sensitive adhesive sheet was prepared by laminating a 0μ polypropylene film.

The resulting pressure-sensitive adhesive sheet had poor adhesion between the surface base material and the pressure-sensitive adhesive, and was unsuitable as a pressure-sensitive adhesive sheet.

Comparative Example 3 An electron beam curable adhesive composition prepared in the same manner as in Example 1 was applied to a 50 μm polyethylene terephthalate film using a die coater so that the weight was 20 g/bore, and the adhesive composition was coated on the surface of the adhesive composition. A release sheet prepared in the same manner as in Example 1 was pasted together, and an acceleration voltage of 1 was applied from the release sheet side.
Electron beam irradiation treatment was performed at 70 kV and an irradiation dose of 4 Mrad. The obtained pressure-sensitive adhesive sheet had scratches on the surface base material, which were thought to have been caused by contact with the coater head, and was unsuitable as a pressure-sensitive adhesive sheet.

The quality of each adhesive sheet was evaluated and the results are shown in Table 1.

[Scars on surface base material]

The scratches were evaluated visually.

O...no scratches ×: There are scratches and there is a problem in practical use.

[Cloudy of adhesive]

O: No clouding observed.

×: There is cloudiness, which poses a practical problem.

[Adhesion]

〇2: Good adhesion between the surface base material and the adhesive.

×: Adhesion between the surface base material and the adhesive is poor.

[Peeling force]

The force when peeling off the surface base material and the adhesive layer at 180° from the release sheet at a speed of 300 mm/min with a width of 5 cm is shown. (g/5 cm) [Smoothness] Judgment was made based on the appearance when attached to a smooth glass plate.

◎...There were no gaps and they were stuck together neatly.

○...There is a slight gap.

Δ...There are many gaps.

Table 1 Procedural Amendment (Spontaneous) May 24, 1999 1999 Patent Application No. 77702 "Effects" The present invention is an excellent adhesive sheet with no scratches on the surface base material and with high transparency of the adhesive. This was the manufacturing method.

Representative: Toshihiko Kawamura 4, Agent residence: 5, Kanzaki Paper Co., Ltd., 4-3-1 Jokoji, Amagasaki City, 660, Date of amendment order Voluntary

Claims (6)

[Claims] (1) An ionizing radiation-curable adhesive composition that is polymerized and/or crosslinked to form an adhesive by irradiation with ionizing radiation is coated on a release sheet, and a surface base material is laminated on the coated layer to form a laminate. A method for producing a pressure-sensitive adhesive sheet, which comprises converting the ionizing radiation-curable pressure-sensitive adhesive composition into a pressure-sensitive adhesive by irradiating it with ionizing radiation. (2) A claim that the smoothness of the surface of the release sheet in contact with the ionizing radiation-curable pressure-sensitive adhesive composition coating layer is 5.0 cmHg or less as measured by a smoother using an air micrometer type smoothness test method (JTAPPI No. 5). The method for producing a pressure-sensitive adhesive sheet according to item (1). (3) The method for producing a pressure-sensitive adhesive sheet according to claim (1), wherein the ionizing radiation-curable pressure-sensitive adhesive composition contains at least one of an acrylic resin, an acrylic prepolymer, and an acrylic monomer. (4) Claim (3) wherein the ionizing radiation-curable adhesive composition further contains a crosslinking agent having a radically polymerizable double bond.
The method for producing the adhesive sheet described above. (5) The method for producing a pressure-sensitive adhesive sheet according to claim (1), wherein the ionizing radiation is an electron beam. (6) An ionizing radiation-curable adhesive composition that is polymerized and/or crosslinked to form an adhesive by irradiation with ionizing radiation is applied to a release sheet, and then a surface base material is laminated to form a laminate that is exposed to ionizing radiation. 1. A method for producing a pressure-sensitive adhesive sheet, which comprises peeling off a release sheet of a pressure-sensitive adhesive sheet obtained by irradiating an ionizing radiation-curable pressure-sensitive adhesive composition to form a pressure-sensitive adhesive, and then bonding the sheet together again.