JP2005343073A - Method for producing structure having release layer capable of adjusting release force - Google Patents

Abstract

【the purpose】
An object is to create a structure having a release layer that can freely adjust the release force.
【Constitution】
A structure having a release layer made of a silicone composition, wherein the release force can be adjusted by irradiating the release layer with an electron beam. Furthermore, 10-100 weight% of silicone which has a 1 or 2 or more radical reactive group in 1 molecule in a silicone composition is contained, The manufacturing method of the said structure characterized by the above-mentioned. Furthermore, the radical reactive group is selected from an acryl group, a methacryloyl group, a styryl group, a vinyl group, and an alkenyl group.

Description

The present invention relates to a structure having a release layer, represented by a release paper, an adhesive label, an adhesive tape, a multilayer label and the like, and a method for producing the structure.

In recent years, the demand for adhesives and adhesive tapes has diversified, and various adhesives and adhesive tapes are used for various applications. Among them, silicone adhesives that adhere well to silicone, etc., which are difficult to stick with ordinary adhesives, have excellent characteristics such as heat resistance, cold resistance, electrical insulation, chemical resistance, and weather resistance. There is much demand. Currently, most of the release agent used for the release liner of the adhesive tape is silicone, and often has a very low release force.

However, there are also important fields of application where a release agent that does not easily release from a sensitive adhesive is required. For example, for industrial labeling that operates at high speed, a release agent having heavy release characteristics or variable release characteristics is required. A silicone heavy release agent is desirable to avoid premature release of the label from the release paper. Variable release characteristics provide a double-sided peelable laminate, that is, a laminate with a different peel force by applying lightly peelable silicone on one side and heavy peelable silicone on the other. Useful in cases.

Accordingly, a method is known in which non-functional and vinyl-functional silicone resins are used as additives for adjusting the peeling force of the silicone composition. Resin and / or liquid mixtures of vinyl functional silicones and SiH functional silicone crosslinkers are cured by known hydrosilylation addition reactions in the presence of noble metal catalysts. By varying the amount of vinyl functional silicone resin added to the main component of the silicone composition, various levels of peel force can be obtained from a given system.

JP-A-06-166820 discloses a trifunctional or tetrafunctional silicone-based release coating composition that can adjust the release force in a silicone release coating mainly composed of vinyl-modified silicone. A method for adjusting the peel force by adding an epoxy-functional silicone resin containing a functional siloxane unit is disclosed.

Japanese Patent Application Laid-Open No. 11-100551 discloses a silicone composition obtained by crosslinking a composition comprising an alkenyl functional polyorganosiloxane and an SiH functional organosiloxane having an incompatible group of 0.1 to 60 mol%. Disclosed are methods for adjusting the degree of incompatibility with silicone coating compositions including alkenyl functional polyorganosiloxanes.

Japanese Patent Application Laid-Open No. 10-195388 discloses a method for adjusting the peeling force using a release regulator containing a mixture of a fluorosilicone resin and an alkenyl functional organopolysiloxane as a release regulator for a silicone release coating.

In JP 09-278893 A, a release modifier comprising a perfluoroalkyl group and a fluorosilicone compound having at least three silicon-bonded hydrogen atoms and an MQ resin having at least one alkenyl group was blended. Disclosed is a method for adjusting peel force using a composition.

Further, JP-A 07-002976 discloses a method for adjusting the peeling force by a unique combination of an epoxy-functional silicone resin and an epoxy-terminated liquid dimethyl silicone as a peeling force adjusting method for an ultraviolet curable epoxy silicone release agent. A method is disclosed.

However, the release composition prepared by the method of adjusting the peeling force by these heat curing or ultraviolet curing can adjust the peeling force only within a certain range based on the composition, and a release sheet having a different peeling force is required. When it is done, it is necessary to make a composition whose composition is changed at any time.

Japanese Patent Laid-Open No. 06-166820 Japanese Patent Laid-Open No. 11-100551 Japanese Patent Laid-Open No. 10-195388 JP 09-278893 A JP 07-002976 A

  An object of this invention is to produce the structure which has a peeling layer which can adjust peeling force freely.

In order to solve the above problem, in the present invention, a means for irradiating the release layer made of the silicone composition with an electron beam was used. The structure of the present invention can increase the peeling force by irradiating a release layer made of a silicone composition obtained by ultraviolet curing with an electron beam. This is not a conventional method for adjusting the peeling force from the raw material such as the composition ratio of the silicone composition or the addition of additives, but various peeling forces can be easily adjusted from those having a certain peeling force.
Also, the peeling force can be adjusted depending on the difference in acceleration voltage and irradiation dose.

That is, the present invention relates to a structure having a release layer made of a silicone composition, and a method for producing a structure in which the release force can be adjusted by irradiating the release layer with an electron beam.
The present invention also relates to a method for producing the above structure, wherein the silicone composition contains 10 to 100% by weight of silicone having one or more radical reactive groups in one molecule.
The present invention also relates to a method for producing the above structure, wherein the radical reactive group is selected from an acryl group, a methacryloyl group, a styryl group, a vinyl group, and an alkenyl group.
Furthermore, this invention relates to the manufacturing method of the structure characterized by the above-mentioned structure being applied to a double-sided tape.

  The peeling structure of the present invention can freely adjust the peeling force by electron beam irradiation without significantly changing the composition.

  First, as a base material used for the peeling structure of the present invention, plastic films such as polyethylene, polypropylene, polyester, polyvinyl chloride, acetate, cellophane, polycarbonate, polytetrafluoroethylene, polyimide, polystyrene; kraft paper, glassine paper Paper such as crepe paper; cloth such as rayon; metal such as aluminum; and composites of these can be used. That is, conventionally used plastic film, paper, non-woven fabric, woven fabric, foam and the like can be used.

  As a method for applying a silicone composition to be a release layer to these substrates, known methods such as roll coating, gravure coating, wire doctor coating, air knife coating, dipping coating, and the like can be employed.

As an ultraviolet curable silicone composition constituting the release layer, generally one or two or more radical reactive groups (acrylic group, methacryloyl group, styryl group, vinyl group, alkenyl group, etc.) are contained in one molecule. The silicone which has can be used suitably.
The content of the silicone having these radical reactive groups is preferably 10 to 100% by weight in the total silicone composition.

Examples of the ultraviolet curable silicone composition include those having a radical reactive group introduced into the side chain, one end, both ends, or both the side chain and both ends of polysiloxane.

  When the silicone composition is irradiated with an electron beam, a bond (—Si—O—O—Si—) in the silicone composition is broken by the electron beam, and a silicon oxide radical (Si—O.) Is generated. This silicon oxide radical (Si—O.) Is considered to cause some reaction with the adhesive layer, which is considered to increase the peeling force.

  In the silicone composition, any one of these silicones can be used alone, or a mixture of two or more of these silicones can be used. Silicones with different degrees of polymerization and monofunctional content or silicones with different functional groups can be used. May be mixed. In addition to the radical reaction type (addition type, polymerization type), a hydrosilylation reaction type or a cationic polymerization type may be used. In addition to the above silicone, oxygen curing inhibition inhibitors, reaction diluents, organic solvents, leveling agents, fillers, antistatic agents, antifoaming agents, pigments, dyes, etc. may be added within the normal range as necessary. May be.

  Examples of radical polymerization initiators can be broadly classified into photocleavage types and hydrogen abstraction types. Examples of the former include benzoin such as benzoin, benzoin methyl ether, benzoin isopropyl ether, α-acryl benzoin, benzyl, 2-methyl-2-morpholino (4-thiomethylphenyl) propan-1-one (Irgacure 907: Ciba Specialty) Chemicals), 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -1-butanone (Irgacure 369: Ciba Specialty Chemicals), benzylmethyl ketal (Irgacure 651: Ciba Specialty Chemicals) 1-hydroxycyclohexyl phenyl ketone (Irgacure 184: manufactured by Ciba Specialty Chemicals), 2-hydroxy-2-methyl-1-phenylpropan-1-one (Darocur 1173: Merck) 1- (4-Isopropylphenyl) -2-hydroxy-2-methylpropan-1-one (Darocur 1116: manufactured by Merck & Co.), 4- (2-hydroxyethoxy) phenyl- (2-hydroxy-2-) Propyl) ketone, 4- (2-acryloyl-oxyethoxy) phenyl-2-hydroxy-2-propylketone, diethoxyacetophenone (ZLI3331: manufactured by Ciba Specialty Chemicals), Esacure KIP100 (manufactured by Ramberty), Lucillin TPO (BASF) Bis (2,6-dimethoxybenzoyl) -2,4,4-trimethyl-pentylphosphine oxide (BAPO1: manufactured by Ciba Specialty Chemicals), bis (2,4,6-trimethylbenzoyl) -phenylphosphine Fin oxide (BAPO : Manufactured by Ciba Specialty Chemicals Inc.), manufactured by BTTB (NOF (Ltd.)), CGI1700 (manufactured by Ciba Specialty Chemicals Inc.) and the like. Examples of the latter include benzophenone, p-methylbenzophenone, p-chlorobenzophenone, tetrachlorobenzophenone, methyl benzoylbenzoate, 4-phenylbenzophenone, hydroxybenzophenone, 4-benzoyl-4'-methyl-diphenyl sulfide, 2-isopropylthioxanthone , 2,4-dimethylthioxanthone, 2,4 diethylthioxanthone, 2,4 dichlorothioxanthone, aryl ketone initiators such as acetophenone, 4,4′-bis (diethylamino) benzophenone, 4,4′-bis (dimethylamino) Dialkylaminoaryl ketone initiators such as benzophenone, isoamyl p-dimethylaminobenzoate, p-dimethylaminoacetophenone, thioxanthone, xanthone-based and halogens thereof Polycyclic carbonyl-based initiators such substitution system is illustrated.

  These can be used alone or in combination. These initiators can be used in the range of 0.1 to 30% by weight in the composition, but preferably in the range of 1 to 15% by weight.

  As the pressure-sensitive adhesive, any material conventionally used as this type of material can be used, and rubber-based, acrylic-based, vinyl-based, silicone-based, etc., which are usually used as pressure-sensitive adhesives, are used. For example, what is published in "Adhesion Handbook" (2nd edition, 1975, published by Nikkan Kogyo Shimbun) can be used.

The basic skeleton includes an elastic resin, a tackifier, a plasticizer and other fillers, and a plasticizer. Examples of the resin of the pressure sensitive adhesive include natural rubber, synthetic isoprene rubber, recycled rubber, acrylic ester, styrene-acrylic ester, styrene-butadiene, ethylene-vinyl acetate, vinyl acetate, vinyl acetate-acrylic ester, Examples thereof include polymers such as ethylene-vinyl chloride, ethylene-acrylic acid ester, ethylene-acrylic acid, butadiene, urethane, styrene-isoprene, acrylonitrile-butadiene, isobutylene, and vinyl ether.

Examples of pressure-sensitive adhesive tackifiers include terpene resins, aliphatic petroleum resins, aromatic petroleum resins, chroman-indene resins, styrene resins, phenol resins, terpene-phenol resins, and rosin derivatives. It is done. As the plasticizer of the pressure-sensitive adhesive, a plasticizer that is liquid at room temperature is mainly used, and examples thereof include mineral oil, lanolin, liquid polybutene, and liquid polyacrylate. Other fillers and additives for pressure sensitive adhesives include zinc oxide, calcium carbonate, clay, aluminum hydroxide, pigments, rubber antioxidants, and the like. In these pressure-sensitive adhesives, the elastic resin, adhesion-imparting agent, plasticizer, other fillers, and additives can be used as one or a mixture of two or more of the above. The pressure sensitive adhesive can be applied on the substrate as an aqueous emulsion type, water soluble type, hot melt type, useless type or organic solvent type. An electron beam curable pressure-sensitive adhesive can also be used.

An electron beam irradiation apparatus employing a curtain method, a scan method, a double scan method, or the like can be used for electron beam irradiation. The acceleration voltage of the electron beam is preferably 10 to 1000 KV, particularly 50 to 300 KV, and the electron beam irradiation amount is preferably 1000 kGy or less. If the acceleration voltage is less than 10 KV, the energy transmittance may be insufficient, and if it exceeds 1000 KV, it may be economically undesirable. Moreover, when an electron beam exceeds 1000 kGy, a base material may deteriorate and it may be unpreferable. The electron beam irradiation direction may be from either the substrate side or the release layer side.

Curing by electron beam irradiation is a radical reaction and depends on the oxygen concentration in the atmosphere. Therefore, substitution with an inert gas such as nitrogen, helium or carbon dioxide was performed, and the oxygen concentration was suppressed to 600 ppm or less, preferably 400 ppm or less. Irradiation is preferably performed in an atmosphere.

Hereinafter, the present invention will be described more specifically with reference to examples.
To 100 parts of silicone composition X-62-7028A (manufactured by Shin-Etsu Chemical Co., Ltd.), 5 parts of photoreaction initiator Darocur 1173 (manufactured by Ciba Specialty Chemicals Co., Ltd.) is added and dispersed to obtain an ultraviolet-type silicone composition. Was made. This ultraviolet curable silicone composition is applied to a polypropylene (PP) film substrate having a thickness of 40 μm with a roll coater so as to have a thickness of 1 μm, and cured with a 128 W / cm metal halide lamp at an exposure amount of 30 mJ / cm 2. A release sheet was prepared.
The produced release sheet was irradiated with an electron beam using a vacuum tube type electron beam irradiation device (Min-EB machine, manufactured by Toyo Ink Co., Ltd. and Curetron, manufactured by Nissin High Voltage). The electron beam irradiation conditions were acceleration voltage 50 kV, 150 kV, irradiation dose: 20 kGy, 40 kGy, 70 kGy, 100 kGy, irradiation atmosphere: nitrogen gas atmosphere (oxygen concentration 200 ppm).

The obtained release sheet was evaluated as follows.
[Evaluation of peel strength]
A double-sided adhesive tape Double-Face made by Toyo Ink Co., Ltd. with a width of 1 inch is pasted on the silicone release layer of the release sheet, and then reciprocated once with a 5 kg roll. After 16 hours at 40 ° C., according to JIS K-6848 The peeling force was measured by 180 ° peeling. The peeling speed was 300 mm / min.
The measurement results of the peeling force are shown in Table 1.

As shown in Table 1, the peeling force increased by irradiating the electron beam as compared with the unirradiated material. In addition, the peeling force increased with increasing acceleration voltage and irradiation dose. From these results, it was shown that the peeling force can be adjusted by the acceleration voltage and the irradiation dose.

Claims (4)

  A structure having a release layer made of a silicone composition, wherein the release force can be adjusted by irradiating the release layer with an electron beam.   The method for producing a structure according to claim 1, wherein the silicone composition contains 10 to 100% by weight of silicone having one or more radical reactive groups in one molecule.   The method for producing a structure according to claim 2, wherein the radical reactive group is selected from an acrylic group, a methacryloyl group, a styryl group, a vinyl group, and an alkenyl group. A structure manufacturing method, wherein the structure according to any one of claims 1 to 3 is applied to a double-sided tape.