Pressure sensitive adhesive sheet, adherend with pressure sensitive adhesive sheet, and method for using pressure sensitive adhesive sheet

Abstract

This invention provides an adhesive sheet that, before irradiation with an active energy line, exhibits good wetting and spreading properties towards the substrate, enabling it to adhere to the substrate with a strong adhesion that is not easily peeled off, and after irradiation with the active energy line, it can be easily peeled off from the substrate. The adhesive sheet of this invention has an adhesive layer. The adhesive layer is a coated dry product containing the following components: one or more non-radical polymerizable compounds (HC) containing active hydrogen groups, having multiple active hydrogen groups and lacking (meth)acrylic groups; one or more radical polymerizable monomers (M), including one or more radical polymerizable monomers (MH) containing active hydrogen groups, wherein the aforementioned one or more radical polymerizable monomers (MH) containing active hydrogen groups have one or more active hydrogen groups and two or more (meth)acrylic groups; a polyfunctional isocyanate compound (I); and a gas generator (G) that generates gas upon irradiation with the active energy line. The adhesion of the adhesive layer ranges from 0.1gf / 25mm to 26gf / 25mm.

Description

Technical Field

[0001] This application claims priority based on Japanese Patent Application No. 2020-095352, filed on June 1, 2020, and all the contents disclosed therein are incorporated herein by reference. This invention relates to an adhesive sheet, an adhesive body having the adhesive sheet, and a method of using the adhesive sheet. Prior Technology

[0002] Previously, adhesive sheets, which form an adhesive layer on a substrate sheet, have been widely used as surface protection sheets for various components. Adhesives include acrylic adhesives, polysiloxane adhesives, and urethane adhesives. While acrylic adhesives offer excellent adhesion, their high adhesion results in poor re-peelability after adhesion to the substrate. Polysiloxane adhesives are prone to contaminating the substrate, and there is also a risk that the relatively low molecular weight polysiloxane resin may volatilize and adsorb onto the surface of electronic components and other machinery, causing adverse conditions. In contrast, urethane adhesives exhibit good adhesion to the substrate, relatively excellent re-peelability, and are less prone to volatilization. Unless otherwise specified in this specification, "adhesive" refers to an adhesive with re-peelability (re-peel type adhesive), and "adhesive sheet" refers to an adhesive sheet with re-peelability (re-peel type adhesive sheet).

[0003] As a method for manufacturing urethane-based adhesives, there are the following methods: a method using a hydroxyl-terminated urethane prepolymer, which is a reaction product of a polyol or other compound containing an active hydrogen group and a polyisocyanate, and a polyfunctional isocyanate compound; and a method in which a polyol and a polyfunctional isocyanate compound react in a single reaction without using a hydroxyl-terminated urethane prepolymer (one-shot method).

[0004] The general manufacturing method of adhesive sheet includes: a coating step, in which an adhesive is applied to a substrate sheet; a heating step, in which the coating layer is heated and dried to form an adhesive layer; a winding step, in which the obtained adhesive sheet is wound onto a core to form an adhesive sheet roll; and a curing step, in which the adhesive sheet roll is cured. [Previous Technical Documents] [Patent Literature]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2015-124301. [Patent Document 2] Japanese Patent Application Publication No. 2016-28020. Summary of the Invention

[0006] [The problem that the invention aims to solve]

[0007] Liquid crystal displays (LCDs) and organic light-emitting diode (OELDs) displays, as well as touch panel displays that combine LCDs with touch panels, are widely used in electronic devices such as televisions (TVs), personal computers (PCs), mobile phones, and mobile information terminals. Carbamate adhesive sheets are well-suited for use as surface protection sheets for LCD and other panel displays, touch panel displays, and substrates (glass substrates, and ITO / glass substrates with ITO (indium tin oxide) films formed on glass substrates, etc.) and optical components manufactured or used in these manufacturing processes.

[0008] In the manufacturing processes of LCD and other panel displays, as well as touch panel displays, it is preferable to be able to transport the adhered object with the adhesive sheet at high speed to the processing unit where the necessary steps are to be performed in order to improve productivity. For example, the industry is researching the following automated high-speed transport: using a vacuum suction component to suction the adhered object with the adhesive sheet from the adhesive sheet side, lift it and transport it to the required location. In the aforementioned automated high-speed conveying process, the adhered body with the adhesive sheet preferably possesses sufficient adhesive force to prevent the adhesive sheet from peeling off from the adhered body during adsorption onto the vacuum adsorption component. On the other hand, for the adhered body with the adhesive sheet after the necessary steps have been completed, it is preferable that the adhesive sheet has relatively low adhesive force to enable high-speed peeling. It is preferable that the adhesive sheet can be easily peeled off from the adhered body after the necessary steps have been completed, and more preferably, the adhesive sheet can peel off naturally.

[0009] As related technologies to this invention, patent document 1 and patent document 2 can be cited. Patent document 1 relates to an acrylic adhesive tape (claim 1). In the adhesive tape described in Patent Document 1, the adhesive layer may contain polyfunctional oligomers or monomers with free radical polymerizability (paragraph 0044). The adhesive layer containing polyfunctional oligomers or monomers with free radical polymerizability can polymerize the oligomers or monomers by irradiation with active energy lines such as ultraviolet light, thereby reducing the adhesive force. In the adhesive tape described in Patent Document 1, the adhesive layer may contain gas generating agents such as azo compounds, azido compounds, tetrazolium compounds and their salts, and bis-tetrazole compounds (paragraph 0037). When the adhesive layer contains a gas generating agent, gas can be generated from the gas generating agent by irradiation with active energy rays such as ultraviolet light. The adhesive tape described in Patent Document 1 can reduce the adhesive force of the adhesive layer by polymerizing oligomers or monomers through irradiation with active energy lines such as ultraviolet light, and generate gas from the gas generator through irradiation with active energy lines such as ultraviolet light, thereby easily peeling the adhesive tape off the adhered body.

[0010] Patent document 2 discloses an adhesive composition containing an adhesive component and a tetrazolium-basic azo compound complex formed by reacting a tetrazolium compound with a basic azo compound (claim 1). Patent document 2 discloses an adhesive tape that is attached to one or both sides of a substrate having an adhesive layer composed of the aforementioned adhesive composition (claim 7). In the [Example] section, only acrylic adhesive compositions and adhesive tapes are manufactured. When the adhesive composition contains a curing adhesive, the curing adhesive may contain multifunctional oligomers or monomers with free radical polymerizability (paragraph 0031). The adhesive layer system containing multifunctional oligomers or monomers with free radical polymerizability can be polymerized by irradiation with active energy lines such as ultraviolet light, thereby reducing the adhesive strength. When the adhesive component contains a curing adhesive, gas can be generated from the tetrazolium compound-basic azo compound complex by irradiation with active energy lines such as ultraviolet light, and the adhesive tape can be easily peeled off from the adherend (paragraph 0022).

[0011] Patent document 1 relates to an acrylic adhesive tape, not a carbamate adhesive sheet. In the [Example] section of Patent Document 2, only an acrylic adhesive composition and an adhesive tape are manufactured. Patent Document 2 does not disclose the specific manufacturing process of the urethane adhesive sheet. Generally speaking, compared with acrylic adhesives, urethane adhesives have higher wetting and spreading properties on the adherend, making them more difficult to peel off from the adherend.

[0012] The present invention is made in view of the above circumstances, and aims to provide an urethane-based adhesive sheet that has good wetting and spreading properties to the substrate before irradiation with active energy lines, has the ability to re-peel the substrate, and can adhere the substrate with an adhesive force that is not easy to peel off, and can be easily peeled off from the substrate after irradiation with active energy lines. [Methods used to solve problems]

[0013] The adhesive sheet of the present invention comprises: a substrate sheet; and an adhesive layer formed on the substrate sheet and having the properties of curing with an active energy line; wherein the aforementioned adhesive layer is a coated and dried product of an adhesive comprising the following components: one or more non-radical polymerizable compounds containing active hydrogen groups (HC), having a plurality of active hydrogen groups and not having (meth)acrylic groups; one or more radical polymerizable monomers (M), comprising one or more radical polymerizable monomers containing active hydrogen groups (MH), wherein the aforementioned one or more radical polymerizable monomers containing active hydrogen groups (MH) have one or more active hydrogen groups and two or more (meth)acrylic groups; a polyfunctional isocyanate compound (I); and a gas generator (G) for generating gas by irradiation with an active energy line; and the aforementioned adhesive layer conforms to JIS (Japanese Industrial Standards). Standards (Japanese Industrial Standard) Z0237, the adhesion force measured using a tensile testing machine at a peel speed of 0.3 m / min and a peel angle of 180° is 0.1 gf / 25 mm to 26 gf / 25 mm.

[0014] The adhesive system of the present invention has the adhesive sheet of the present invention attached to the adhesive body.

[0015] The method of using the first adhesive sheet of the present invention includes the following steps: attaching the adhesive sheet of the present invention to the surface of the object to be adhered; and irradiating the adhesive sheet attached to the surface of the object to the surface with active energy lines to reduce the adhesive force of the adhesive sheet.

[0016] The method of using the second adhesive sheet of the present invention includes the following steps: attaching the adhesive sheet of the present invention to the surface of the object to be adhered; and irradiating the adhesive sheet attached to the surface of the object with active energy lines to reduce the adhesive force of the adhesive sheet, so that the self-weight adhesion time of the adhesive layer to the acrylic resin board after irradiation by the active energy lines, as measured by the following method, is more than 30 seconds, thereby reducing the adhesive force and peeling the adhesive sheet off from the object to be adhered. Holding the adhesive sheet with a width of 100mm and a length of 200mm at both ends along its long side, bend the adhesive sheet with the adhesive layer facing outwards, bringing the two ends together. In this position, bring the central portion of the adhesive sheet (with the adhesive layer in contact with the acrylic resin board). Release both hands from the aforementioned ends. Measure the time from releasing the hands until the adhesive layer is fully adhered to the acrylic resin board; this is the self-weight adhesion time. [Invention Benefits]

[0017] According to the present invention, an urethane-based adhesive sheet is provided, which has good wetting and spreading properties on the adherend before irradiation with active energy lines, has the ability to re-peel the adherend after re-attaching, and can adhere the adherend with an adhesive force that is not easy to peel off, and can be easily peeled off from the adherend after irradiation with active energy lines. Simple Explanation of the Diagram

[0018] [Figure 1] is a schematic cross-sectional view of the adhesive sheet of the first embodiment of the present invention. [Figure 2] is a schematic cross-sectional view of the adhesive sheet of the second embodiment of the present invention. Implementation

[0019] The present invention relates to a carbamate-based adhesive sheet having: a substrate sheet and an adhesive layer formed on at least one side of the substrate sheet. In this invention, the adhesive layer is composed of a coated and dried product of a carbamate adhesive, comprising a reaction product of one or more compounds containing active hydrogen groups and one or more polyfunctional isocyanate compounds. In this invention, the adhesive layer has active energy line hardening properties.

[0020] The adhesive sheet of the present invention is suitable as a surface protective sheet for panel displays such as liquid crystal displays (LCDs) and organic electroluminescent displays (OELDs), as well as touch panel displays formed by combining the panel displays with touch panels, and substrates (glass substrates, and ITO / glass substrates with ITO (indium tin oxide) films formed on glass substrates, etc.) and optical components manufactured or used in the manufacturing process of these. In this specification, the term "adhesive body with adhesive sheet" refers to a laminate in which an adhesive sheet is attached to the surface of an adhesive body such as a glass substrate, an ITO / glass substrate on which an ITO (indium tin oxide) film is formed, and optical components.

[0021] [Adhesive] The adhesive used as the adhesive layer material comprises: one or more non-radical polymerizable compounds (HC) containing active hydrogen groups, having multiple active hydrogen groups and not having (meth)acrylic groups; one or more radical polymerizable monomers (M), including one or more radical polymerizable monomers (MH) containing active hydrogen groups, wherein the monomers have one or more active hydrogen groups and two or more (meth)acrylic groups; a polyfunctional isocyanate compound (I); and a gas generator (G) that generates gas by irradiation with an active energy line.

[0022] Compounds containing active hydrogen groups (HC) are non-radical polymerizable compounds that have multiple active hydrogen groups but do not have (meth)acrylic acid groups. Examples of active hydrogen groups include hydroxyl (hydroxyl), mercapto, and amino groups (unless otherwise specified in this specification, amino groups include imine groups). Examples of compounds (HC) containing active hydrogen groups include: polyols having multiple hydroxyl groups, polyamines having multiple amino groups, amino alcohols having both amino and hydroxyl groups, and polythiols having multiple mercapto groups. These compounds (HC) containing active hydrogen groups can be non-polymers or polymers. One or more of these can be used. Among these, polyols are preferred. Polyamines and polythiols are highly reactive and have short pot lives, so they are preferably used in combination with polyols when used in these applications. In addition, when the active hydrogen group of the polyol is a secondary hydroxyl group, the initial curing property of the carbamate adhesive will not be improved. Therefore, from the viewpoint of pot life and initial curing property, polyols containing primary hydroxyl groups with moderate reactivity are preferred.

[0023] [Hydroxy-terminated carbamate prepolymer (UPH)] The preferred form of the compound (HC) containing an active hydrogen group is a hydroxyl-terminated carbamate prepolymer (UPH), which is a reaction product obtained by copolymerizing one or more compounds (HX) containing active hydrogen groups with one or more polyisocyanates (N). The copolymerization reaction may be carried out in the presence of one or more catalysts, if desired. One or more solvents may be used in the copolymerization reaction, if desired. The hydroxyl-terminated carbamate prepolymer (UPH) does not contain (meth)acrylic acid groups.

[0024] [Compounds containing active hydrogen groups (HX)] The active hydrogen-containing compound (HX) used as a raw material for hydroxyl-terminated aminocarbamate prepolymer (UPH) is a compound having multiple active hydrogen groups and no (meth)acrylic acid group. Examples of active hydrogen groups include hydroxyl (hydroxyl), mercapto, and amino groups (unless otherwise specified in this specification, amino groups include imine groups). Examples of compounds (HX) containing active hydrogen groups include: polyols having multiple hydroxyl groups, polyamines having multiple amino groups, amino alcohols having both amino and hydroxyl groups, and polythiols having multiple mercapto groups. These compounds (HX) containing active hydrogen groups can be non-polymers or polymers. One or more of these can be used. Polyols are preferred. Polyamines and polythiols have high reactivity with polyisocyanates, so the reaction must be carefully controlled when using them. Furthermore, the reaction product of polyamines and polyisocyanates has greater cohesive power than the reaction product of polyols and polyisocyanates, making it more prone to high viscosity. Therefore, it is preferable to reduce the concentration used in UPH manufacturing or to use polyamines and polyols in combination.

[0025] Examples of polyols that can be used as compounds (HX) containing active hydrogen groups include: polyester polyols, polyether polyols, polyacrylic acid polyols, polycaprolactone polyols, polycarbonate polyols, and castor oil-based polyols. Polyester polyols, polyether polyols, and combinations thereof are preferred. One or more compounds (HX) containing active hydrogen groups are preferably polyether polyols.

[0026] Known polyester polyols can be used as compounds (HX) containing active hydrogen groups. Examples of polyester polyols include compounds (esterified compounds) obtained by esterification reactions of one or more polyol components with one or more acid components.

[0027] Polyols used as raw materials can include: ethylene glycol (EG), propylene glycol (PG), diethylene glycol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, 2-butyl-2-ethyl-1,3-propanediol, 2,4-diethyl-1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 2-ethyl-1,3-hexanediol, 1,8-octanediol, 1,9-nonanediol, 2-methyl-1,8-octanediol, 1,8-decanediol, octadecanediol, glycerol, trimethylolpropane, and neopentyl tertrol, etc.

[0028] Acidic components used as raw materials include: succinic acid, methylsuccinic acid, adipic acid, pimelic acid, azelaic acid, sebacic acid, 1,12-dodecanoic acid, 1,14-tetradecanoic acid, dimer acid, 2-methyl-1,4-cyclohexanedicarboxylic acid, 2-ethyl-1,4-cyclohexanedicarboxylic acid, phthalic acid, isophthalic acid, terephthalic acid, 1,4-naphthalenedicarboxylic acid, 4,4'-biphenyl dicarboxylic acid, and their anhydrides.

[0029] As a polyether polyol that can be used as a compound (HX) containing an active hydrogen group, known polyether polyols can be used. Examples of polyether polyols include: compounds (addition polymers) obtained by adding one or more ethylene oxide compounds by using a compound containing an active hydrogen group as a starting agent.

[0030] Examples of initiators include compounds containing hydroxyl groups and amines. Specific examples include: difunctional initiators such as ethylene glycol (EG), propylene glycol (PG), 1,4-butanediol, neopentyl glycol, butylethylpentyl glycol, N-aminoethylethanolamine, isophorone diamine, and xylene diamine; trifunctional initiators such as glycerol, trimethylolpropane, and triethanolamine; and tetrafunctional initiators such as neopentyltetrol, ethylenediamine, and aromatic diamines. Examples of ethylene oxide compounds include: ethylene oxide (EO), propylene oxide (PO), and butylene oxide (BO), as well as tetrahydrofuran (THF).

[0031] As a polyether polyol, it is preferred to be an alkylene oxide adduct of a compound containing active hydrogen (also known as a polyalkylene oxide polyol). Among them, polyethylene glycol (PEG), polypropylene glycol (PPG), PPG with ethylene oxide (EO) added to the end (PPG-EO), and polyalkylene oxide diols such as polytetramethylene glycol are preferred; trifunctional polyether polyols such as alkylene oxide adducts of glycerol are also preferred.

[0032] Examples of polyamines that can be used as compounds containing active hydrogen groups (HX) include: ethylenediamine, 1,2-propanediamine, 1,3-propanediamine, 1,4-butanediamine, 1,5-pentanediamine, 1,6-hexanediamine, 1,7-heptanediamine, 1,8-octanediamine, 1,9-nonanediamine, 1,10-decanediamine, 1,12-dodecanediamine, 1,14-tetradecanediamine, 1,16-hexadecanediamine, hexamethylenediamine, trimethylhexamethylenediamine, iminodipropylamine, methyliminodipropylamine, 1,5-diamino-2-methylpentane, isophoronediamine, 1,3-diaminomethylcyclohexane, 1-cyclohexylamino-3-aminopropane, 3-aminomethyl-3,3,5-trimethyl-cyclohexylamine, and dimethyleneamine with a norcamphene skeleton. Aliphatic polyamines such as m-xylenediamine (MXDA), hexamethylenediamine-carbamate, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, and pentaethylenehexamine; aromatic polyamines such as 3,3'-dichloro-4,4'-diaminodiphenylmethane (MOCA), 4,4'-diaminodiphenylmethane, 2,4'-diaminodiphenylmethane, 3,3'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 2,2'-diaminobiphenyl, 3,3'-diaminobiphenyl, 2,4-diaminophenol, 2,5-diaminophenol, o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, 2,3-toluenediamine, 2,4-toluenediamine, 2,5-toluenediamine, 2,6-toluenediamine, 3,4-toluenediamine, and diethyltoluenediamine.

[0033] Examples of amino alcohols that can be used as compounds (HX) containing active hydrogen groups include: monoethanolamine, diethanolamine, 2-amino-2-methyl-1-propanol, tris(hydroxymethyl)aminomethane and 2-amino-2-ethyl-1,3-propanediol, etc., which are monoamines containing hydroxyl groups; and N-(2-hydroxypropyl)ethanolamine, etc., which are diamines containing hydroxyl groups.

[0034] Examples of polythiols that can be used as compounds containing active hydrogen groups (HX) include: methanedithiol, 1,3-butanedithiol, 1,4-butanedithiol, 2,3-butanedithiol, 1,2-benzenedithiol, 1,3-benzenedithiol, 1,4-benzenedithiol, 1,10-decanedithiol, 1,2-ethanedithiol, 1,6-hexanedithiol, 1,9-nonanedithiol, 1,8-octanedithiol, 1,5-pentanedithiol, 1,2-propanedithiol, 1,3-propanedithiol, and toluene-3,4-dimethylbenzenediol. - Dithiols, 3,6-dichloro-1,2-benzenedithiols, 1,5-naphthalenedithiols, 1,2-benzenedimethylthiols, 1,3-benzenedimethylthiols, 1,4-benzenedimethylthiols, 4,4'-thiodibenzenedithiols, 2,5-dimercapto-1,3,4-thiadiazoles, 1,8-dimercapto-3,6-dioxaoctane, 1,5-dimercapto-3-thiopentane, 2-di-n-butylamino-4,6-dimercapto-symmetric triazines, and thiol-terminated polymers (polysulfide polymers, etc.).

[0035] One or more compounds (HX) containing active hydrogen groups may include difunctional compounds containing active hydrogen groups and / or trifunctional or higher compounds containing active hydrogen groups. Generally, difunctional compounds containing active hydrogen groups have two-dimensional crosslinking properties, which can impart appropriate flexibility to the adhesive layer. Trifunctional or higher compounds containing active hydrogen groups have three-dimensional crosslinking properties, which can impart appropriate hardness to the adhesive layer. The adhesive strength, cohesive strength, and re-peelability of the carbamate adhesive can be adjusted by selecting the number of functional groups (number of active hydrogen groups) of each compound (HX). The number of functional groups of each material can be selected in a way that optimizes the adhesive strength, cohesive strength, and re-peelability properties, depending on the application and other factors. In order to easily combine adhesion and re-peelability, one or more compounds containing active hydrogen groups (HX) are preferably compounds containing active hydrogen groups that are difunctional or trifunctional or more.

[0036] There are no particular limitations on the number-average molecular weight (Mn) of the compounds (HX) containing active hydrogen groups. In terms of better adhesion and wettability of the adhesive layer, the Mn of the compounds (HX) containing active hydrogen groups is preferably 50 to 20,000, more preferably 100 to 7,000, and even more preferably 400 to 5,000.

[0037] [Polyisocyanate (N)] Polyisocyanates (N) used as raw materials for hydroxyl-terminated carbamate prepolymers (UPH) can be those known to be used, such as aromatic polyisocyanates, aliphatic polyisocyanates, and alicyclic polyisocyanates. One or more polyisocyanates (N) may be used. There is no particular limitation on the functional group of polyisocyanate (N), but it is preferably difunctional. That is, it is more preferably that one or more polyisocyanates (N) mainly include difunctional polyisocyanates, and more preferably that one or more polyisocyanates (N) are difunctional polyisocyanates.

[0038] Examples of aromatic polyisocyanates include: 1,3-phenyl diisocyanate, 4,4'-diphenyl diisocyanate, 1,4-phenyl diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 4,4'-toluidine diisocyanate, 2,4,6-triisocyanate toluene, 1,3,5-triisocyanate benzene, anisidine diisocyanate, 4,4'-diphenyl ether diisocyanate, 4,4',4”-triphenylmethane triisocyanate, ω,ω'-diisocyanate-1,3-dimethylbenzene, ω,ω'-diisocyanate-1,4-dimethylbenzene, ω,ω'-diisocyanate-1,4-diethylbenzene, 1,4-tetramethylxylene diisocyanate, and 1,3-tetramethylxylene diisocyanate.

[0039] Examples of aliphatic polyisocyanates include: trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (HDI), pentamethylene diisocyanate, 1,2-endenylpropyl diisocyanate, 2,3-endenylbutyl diisocyanate, 1,3-endenylbutyl diisocyanate, dodecamethylene diisocyanate, and 2,4,4-trimethylhexamethylene diisocyanate.

[0040] Examples of alicyclic polyisocyanates include: isophorone diisocyanate (IPDI), 1,3-cyclopentane diisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, methyl-2,4-cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate, 4,4'-methylene bis(cyclohexyl isocyanate), and 1,4-bis(isocyanate methyl)cyclohexane, etc.

[0041] In addition, examples of polyisocyanates include: trimethylolpropane adducts, biurets, urethane esters, and trimers (which contain isocyanurate rings).

[0042] The preferred raw material formulations for hydroxyl-terminated carbamate prepolymers (UPH) are as follows. Preferably, the raw material formulation is determined by a ratio (NCO / H ratio) of the mole number of isocyanate groups (NCO) in polyisocyanate (N) to the total mole number of active hydrogen groups (H) in various compounds (HX) containing active hydrogen groups, which is 0.20 to 0.95, more preferably 0.40 to 0.80. The closer the NCO / H ratio is to 1, the more prone there is to gelation during the synthesis of hydroxyl-terminated carbamate prepolymers (UPH). If the NCO / H ratio is below 0.95, gelation during the synthesis of hydroxyl-terminated carbamate prepolymers (UPH) can be effectively suppressed.

[0043] [catalyst] During the polymerization of hydroxyl-terminated carbamate prepolymers (UPH), one or more catalysts may be used as needed. Known catalysts include tertiary amine compounds and organometallic compounds. Examples of tertiary amine compounds include triethylamine, triethylenediamine, and 1,8-diazabicyclo(5,4,0)-undecene-7 (DBU). As organometallic compounds, examples include tin-based compounds and non-tin-based compounds. Examples of tin-based compounds include: dibutyltin dichloride, dibutyltin oxide, dibutyltin dibromide, dibutyltin dimaleate, dibutyltin dilaurate (DBTDL), dibutyltin diacetate, dioctyltin dilaurate, dibutyltin sulfide, tributyltin sulfide, tributyltin oxide, tributyltin acetate, triethyltin ethoxide, tributyltin ethoxide, dioctyltin oxide, tributyltin chloride, tributyltin trichloroacetate, and tin 2-ethylhexanoate. Examples of non-tin compounds include: titanium-based compounds such as dibutyltitanium dichloride, tetrabutyl titanate, and butoxytitanium trichloride; lead-based compounds such as lead oleate, lead 2-ethylhexanoate, lead benzoate, and lead naphthenate; iron-based compounds such as iron 2-ethylhexanoate and iron acetone; cobalt-based compounds such as cobalt benzoate and cobalt 2-ethylhexanoate; zinc-based compounds such as zinc naphthenate and zinc 2-ethylhexanoate; and zirconium-based compounds such as zirconium naphthenate. The type and amount of catalyst can be appropriately selected within the range where the reaction proceeds well.

[0044] When multiple compounds (HX) with different reactivity groups are used together, there is a risk of poor polymerization stability or turbidity of the reaction solution in a single-catalyst system due to the differences in their reactivity. In such cases, using two or more catalysts makes it easier to control the reaction (e.g., reaction rate) and solves the above problems. In systems using multiple compounds (HX) with different reactivity groups, it is preferable to use two or more catalysts. There are no particular limitations on the combination of two or more catalysts; examples include tertiary amine / organometallic, tin-based / non-tin-based, and tin-based / tin-based catalysts. Tin-based / tin-based catalysts are preferred, and more preferably dioctyltin dilaurate and tin 2-ethylhexanoate. There is no particular limitation on the mass ratio of tin 2-ethylhexanoate to dioctyltin dilaurate (tin 2-ethylhexanoate / dioctyltin dilaurate), but it is preferably greater than 0 to less than 1, and more preferably 0.2 to 0.8. If this mass ratio is less than 1, the catalytic activity is well balanced, effectively inhibiting gelation and turbidity of the reaction solution, and further improving the polymerization stability.

[0045] There is no particular limitation on the amount of one or more catalysts used, but it is preferably 0.01% to 1.0% by mass relative to the total amount of one or more compounds containing active hydrogen groups (HX) and one or more polyisocyanates (N).

[0046] [solvent] During the polymerization of hydroxyl-terminated carbamate prepolymers (UPH), one or more solvents may be used as needed. Known solvents include methyl ethyl ketone, ethyl acetate, toluene, xylene, and acetone. Ethyl acetate and toluene are particularly preferred in terms of the solubility of the hydroxyl-terminated carbamate prepolymer (UPH) and the boiling point of the solvent.

[0047] [Polymerization method for hydroxyl-terminated carbamate prepolymers (UPH)] There are no particular restrictions on the polymerization method for hydroxyl-terminated carbamate prepolymers (UPHs), and known polymerization methods such as bulk polymerization and solution polymerization can be used. The polymerization sequence of hydroxyl-terminated carbamate prepolymer (UPH) can be listed as follows: sequence 1) feeding one or more compounds (HX) containing active hydrogen groups, one or more polyisocyanates (N), one or more catalysts as needed, and one or more solvents as needed into a flask; and sequence 2) feeding one or more compounds (HX) containing active hydrogen groups, one or more catalysts as needed, and one or more solvents as needed into a flask, and then adding one or more polyisocyanates (N) dropwise into the flask, etc. When using a variety of compounds containing active hydrogen groups (HX) and / or polyisocyanates (N), the reaction can also be carried out in multiple stages.

[0048] When using a catalyst, the reaction temperature is preferably below 100°C, more preferably between 50°C and 95°C, and even more preferably between 60°C and 85°C. If the reaction temperature is above 100°C, it may be difficult to control the reaction rate and polymerization stability, and it may be difficult to generate hydroxyl-terminated carbamate prepolymers (UPH) with the desired molecular weight. When not using a catalyst, the reaction temperature is preferably above 100°C, and more preferably above 110°C.

[0049] [Polyfunctional isocyanate compound (I)] As a polyfunctional isocyanate compound (I), compounds known to be used, such as polyisocyanates (N) which are used as raw materials for hydroxyl-terminated urethane prepolymers (UPH), can be used (specifically aromatic polyisocyanates, aliphatic polyisocyanates, aromatic aliphatic polyisocyanates, alicyclic polyisocyanates, and their trimethylolpropane adducts / biuretes / urethane esters / trimers). One or more polyfunctional isocyanate compounds (I) may be used. There is no particular limitation on the number of functional groups of the polyfunctional isocyanate compound (I), but it is preferably trifunctional or more. That is, it is preferable that one or more polyfunctional isocyanate compounds (I) mainly contain polyisocyanates with trifunctionality or more, and more preferably that one or more polyfunctional isocyanate compounds (I) are polyisocyanates with trifunctionality or more.

[0050] [Free radical polymerizable monomer (M)] The adhesive used as the adhesive layer material contains one or more free radical polymerizable monomers (M). A free radical polymerizable monomer (M) is a material that polymerizes and hardens by irradiation with active energy lines such as ultraviolet light and electron beams in the presence of a free radical polymerization initiator (RI). Preferably, the free radical polymerizable monomer (M) is UV-curable, meaning it hardens by ultraviolet irradiation. Unless otherwise specified, ultraviolet light (hereinafter sometimes simply referred to as "UV") is defined in this specification as "light emitted by a high-pressure mercury lamp that produces ultraviolet light in the range of 250 nm to 440 nm."

[0051] If an active energy line is irradiated onto the adherend containing the adhesive sheet, one or more free radical polymerizable monomers (M) contained in the adhesive layer will polymerize and harden, reducing the adhesive strength and wettability of the adhesive layer, making it easier to peel the adhesive sheet off from the adherend.

[0052] When the main component, containing an active hydrogen group, and the free radical polymerizable monomer (M) both possess (meth)acrylic acid groups, the adhesive layer's reactivity is excessively high, raising concerns that it may easily initiate and undergo reactions due to exposure to trace amounts of ultraviolet light from ambient light such as fluorescent lamps and sunlight, thus reducing the adhesive strength of the adhesive layer. The following situation is also undesirable: during vacuum adsorption and transport of the adhered object, exposure to trace amounts of ultraviolet light from ambient light can further reduce the adhesive strength of the adhesive layer. In this invention, a compound containing an active hydrogen group (HC) (preferably a hydroxyl-terminated aminocarbamate prepolymer (UPH)) that does not have (meth)acrylic acid group and has non-radical polymerizability is used as the main component of the compound containing an active hydrogen group. Therefore, it is possible to suppress the cross-linking reaction caused by the small amount of ultraviolet light contained in the ambient light, and to suppress the peeling of the self-adhesive sheet of the adhered body during vacuum adsorption and transportation of the adhered body.

[0053] In this invention, one or more free radical polymerizable monomers (M) comprise one or more free radical polymerizable monomers (MH) containing active hydrogen groups. The aforementioned one or more free radical polymerizable monomers (MH) containing active hydrogen groups have one or more active hydrogen groups and two or more (meth)acrylic acid groups, and may contain one or more other free radical polymerizable monomers (MO) as needed. The active hydrogen groups contained in the compound (MH) containing active hydrogen groups can include hydroxyl (hydroxyl), mercapto and amino groups (unless otherwise specified in this specification, amino groups include imine groups), etc., with hydroxyl and amino groups being more preferred, and hydroxyl being particularly preferred. In this specification, "(meth)acryl" refers to acrylonitrile and methacryl.

[0054] One or more non-radical polymerizable compounds containing active hydrogen groups (HC) and one or more radical polymerizable monomers containing active hydrogen groups (MH) can react with a polyfunctional isocyanate compound (I). The adhesive layer may contain these reaction products. One or more free radical polymerizable monomers containing active hydrogen groups (MH) can be bonded to urethane resins via polyfunctional isocyanate compounds (I) during polymerization, which can more effectively cause the hardening of the adhesive layer and the reduction of adhesion and wettability caused by the hardening of the adhesive layer.

[0055] The monomer (MH) containing one or more active hydrogen groups is preferably a monomer (MHT) containing one or more trifunctional active hydrogen groups, wherein the aforementioned monomer (MHT) containing one or more trifunctional active hydrogen groups has three or more (meth)acrylic acid groups. In this case, a cross-linking reaction can be carried out during free radical polymerization, effectively causing hardening of the adhesive layer and a decrease in adhesive strength and wettability due to the hardening of the adhesive layer.

[0056] In terms of making the above-mentioned effects more effective, the number of (meth)acrylic acid groups in the monomer (MH) containing active hydrogen groups is preferably 4 or more, and more preferably 5 or more. That is, one or more monomers containing active hydrogen groups (MH) are more preferably monomers containing one or more tetrafunctional active hydrogen groups (MHQ), wherein the aforementioned one or more tetrafunctional active hydrogen groups (MHQ) have four or more (meth)acrylic groups. One or more monomers containing active hydrogen groups (MH) are particularly preferably monomers containing one or more pentafunctional active hydrogen groups (MHF), wherein the aforementioned one or more pentafunctional active hydrogen groups (MHF) have five or more (meth)acrylic groups.

[0057] Monomers (MH) containing one or more active hydrogen groups and two (meth)acrylic groups can be exemplified by: glyceryl diacrylate, glyceryl dimethacrylate, and 2-hydroxy-3-acryloyloxypropyl methacrylate. One or more of these may be used.

[0058] Examples of monomers (MH) containing one or more active hydrogen groups and three or more (meth)acrylic groups include: tris(2-hydroxyethyl)isocyanurate tri(meth)acrylate, neopentyl tetroxide tri(meth)acrylate, dinepentyl tetroxide tetra(meth)acrylate, and dinepentyl tetroxide penta(meth)acrylate. One or more of these may be used.

[0059] One or more radical polymerizable monomers (M) may, as needed, contain one or more other radical polymerizable monomers (MO) besides monomers containing active hydrogen groups (MH). Examples of radical polymerizable monomers (MO) include compounds having two or more (meth)acrylic acid groups and not having active hydrogen groups.

[0060] One or more other free radical polymerizable monomers (MO) are preferably free radical polymerizable monomers (MOT) containing one or more trifunctional or higher free radical polymerizable monomers (MOT), wherein the aforementioned one or more trifunctional or higher free radical polymerizable monomers (MOT) have three or more (meth)acrylic groups. In this case, a cross-linking reaction can be carried out during free radical polymerization, effectively causing hardening of the adhesive layer, and a decrease in adhesive strength and a decrease in wettability due to the hardening of the adhesive layer.

[0061] In terms of making the above-mentioned effects more effective, the number of (meth)acrylic acid groups in the free radical polymerizable monomer (MO) is preferably four or more, and more preferably five or more. That is, one or more radical polymerizable monomers (MO) are more preferably radical polymerizable monomers (MOQ) containing one or more tetrafunctional radical polymerizable monomers (MOQ), wherein the aforementioned one or more tetrafunctional radical polymerizable monomers (MOQ) have four or more (meth)acrylonitrile groups. One or more radical polymerizable monomers (MO) are particularly preferably radical polymerizable monomers (MOF) containing one or more pentafunctional radical polymerizable monomers (MOF), wherein the aforementioned one or more pentafunctional radical polymerizable monomers (MOF) have five or more (meth)acrylonitrile groups.

[0062] Examples of free radical polymerizable monomers (MOs) having two (meth)acrylic groups and lacking active hydrogen groups include: ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, ethoxylated bisphenol A dimethacrylate, tricyclodecanediethanol dimethacrylate, 1,4-butanediol dimethacrylate, 1,6-hexanediol dimethacrylate, 1,9-nonanediol dimethacrylate, and neopentyl glycol dimethacrylate. One or more of these may be used.

[0063] Examples of free radical polymerizable monomers (MOs) having three or more (meth)acrylic groups and lacking active hydrogen groups include: trimethylolpropane tri(meth)acrylate, glycerol tri(meth)acrylate, ethylene oxide-modified trimethylolpropane tri(meth)acrylate, propylene oxide-modified trimethylolpropane tri(meth)acrylate, tri(acryloxyethyl)isocyanurate, caprolactone-modified tri(acryloxyethyl)isocyanurate, trimethylolpropane tri(meth)acrylate, neopentyltetra(meth)acrylate, dinepentyltetra(meth)acrylate, and caprolactone-modified... Dinepentylenetetra(hexa(meth)acrylate) and 1,2,3-cyclohexanetetra(meth)acrylate, etc., are ester compounds of polyols and (meth)acrylates; polyurethane poly(meth)acrylates, polyester poly(meth)acrylates, polyether poly(meth)acrylates, polyacrylic acid poly(meth)acrylates, polyalkyd poly(meth)acrylates, polyepoxy poly(meth)acrylates, polyspiroacetal poly(meth)acrylates, polybutadiene poly(meth)acrylates, polythiol polyene poly(meth)acrylates, and polysilicon poly(meth)acrylates, etc., are multifunctional poly(meth)acrylate compounds. One or more of these may be used.

[0064] In terms of more effectively causing the hardening of the adhesive layer and the reduction of adhesion and wettability caused by the hardening of the adhesive layer, the total amount of one or more free radical polymerizable monomers (M) is preferably 20% to 100% by mass, more preferably 40% to 100% by mass, further preferably 60% to 100% by mass, particularly preferably 70% to 100% by mass, and most preferably 80% to 100% by mass. The “one or more functional free radical polymerizable monomers” mentioned here includes one or more functional free radical polymerizable monomers containing active hydrogen groups (MHF) and / or one or more functional free radical polymerizable monomers (MOF).

[0065] In terms of more effectively causing the hardening of the adhesive layer and the reduction of adhesion and wettability due to the hardening of the adhesive layer, the amount of one or more functional monomers containing active hydrogen groups (MHF) is preferably 20% to 100% by mass, more preferably 40% to 100% by mass, further preferably 60% to 100% by mass, particularly preferably 70% to 100% by mass, and most preferably 80% to 100% by mass, relative to the total amount of one or more free radical polymerizable monomers (M).

[0066] [Gas Generator (G)] Gas generator (G) is a compound that generates gas by irradiation with active energy lines such as ultraviolet light and electron beams. When an active energy line is irradiated onto an adherend containing an adhesive sheet, gas is generated by the gas generator (G) contained in the adhesive layer. This generated gas can remain between the adherend and the adhesive layer. A sufficient amount of gas remaining between the adherend and the adhesive layer can exert its effect by causing the adhesive layer to peel off naturally from the adherend.

[0067] In the adhesive sheet of this invention, by irradiating with active energy lines, the free radical polymerizable monomer (M) polymerizes, thereby reducing the adhesive strength and wetting diffusion of the adhesive layer, and generating gas from the adhesive layer. These effects complement each other, enabling the adhesive sheet to be easily peeled off from the adherend after irradiation with active energy lines. For example, the adhesive sheet can be easily peeled off from the adherend by means of blowing air, or it can be peeled off from the adherend naturally.

[0068] The gas generator (G) is preferably a nitrogen-containing compound containing N=N bonds that generates nitrogen gas by irradiation of an active energy line. The gas generator (G) is preferably at least one selected from the group consisting of azo compounds, azido compounds, tetrazolium compounds, tetrazolium compound salts, and bis-tetrazole compounds. Among these, azo compounds are particularly preferred from the viewpoint of chemical stability and ease of gas generation control.

[0069] The theoretically calculated N2 production volume per 1g based on the chemical structural formula of the gas generator (G) is preferably 30mL / g to 400mL / g, more preferably 40mL / g to 200mL / g, and even more preferably 50mL / g to 120mL / g. If the volume of N2 produced per 1g is 30mL / g or more, a sufficient amount of gas can be stably produced when the adhesive layer is irradiated with an active energy line. If the volume of N2 produced per 1g is 400mL / g or less, the reaction can be stably suppressed from easily initiating and proceeding due to the small amount of ultraviolet light contained in ambient light such as fluorescent lamps and sunlight.

[0070] The volume produced by each 1g of N2 is calculated by the following formula. [Volume produced per 1g of N₂] (mL / g) = 22.4 × 1000 × [N in one molecule = number of N-groups] / [Molecular weight] In the example of gas generating agent (G), the theoretical values ​​of molecular weight of each compound / number of N groups in one molecule / volume of N2 generated per 1g are shown in Table 1. In the table, gas generators (G11) to (G19) are examples of azo compounds. In the table, gas generators (G21) to (G22) are examples of tetrazolium compounds.

[0071] [Table 1] compound name molecular weight The number of N bases contained in one molecule The volume produced by N 2 per 1g [mL / g] G-11 1,1'-Azobis(cyclohexane-1-carboxynitrile) 244.34 1 91.7 G-12 2,2'-Azobis[2-methyl-N-(2-hydroxyethyl)propionamide] 288.34 1 77.7 G-13 2,2'-Azobis[N-(2-propenyl)-2-methylpropionic acid] 280.37 1 79.9 G-14 2,2'-Azobis(N-butyl-2-methylpropionic acid) 312.45 1 71.7 G-15 2,2'-Azobis(isobutyronitrile) (AIBN) 164.20 1 136.4 G-16 2,2'-Azobis(2-methylbutyronitrile) (AMBN) 192.30 1 116.5 G-17 2,2'-Azobis(2,4-dimethylpentanonitrile) (ADVN) 248.40 1 90.2 G-18 2,2'-Azobis(methyl isobutyrate) (MAIB) 230.30 1 97.3 G-19 1,1'-Azobis(1-acetoxy-1-phenyl-ethane) 354.40 1 63.2 G-21 1-Phenylacetazole 5-Mercapto-1H-Tetrazole (PMT) 178.22 2 251.4 G-22 5-Phenylacetazole (P5T) 146.15 2 306.5

[0072] The nitrogen-containing compounds listed in Table 1 include compounds known as free radical polymerization initiators, which generate free radicals by heat and become the starting point for polymerization. The amount used as a free radical polymerization initiator is usually less than 1 part by mass relative to a total of 100 parts by mass of one or more monomers that are the target monomers for polymerization. The content of the gas generator (G) in the adhesive layer is greater than the amount of free radical polymerization initiator added, preferably 2% by mass or more, more preferably 3% to 30% by mass, and even more preferably 5% to 20% by mass. If the content of gas generator (G) in the adhesive layer is 2% by mass or more, the amount of gas generated by the irradiation of the active energy line becomes sufficient, and the adhesive sheet can be easily peeled off from the adherend after the active energy line irradiation. If the content of the gas generating agent (G) is 30% by mass or less, it has sufficient transparency as a surface protective film for LCD and other panel displays, touch panel displays, and substrates and optical components manufactured or used in their manufacturing process, and it is easy to obtain an adhesive film with good UV transmittance. The optimal UV transmittance will be discussed later. Furthermore, when a compound known as a free radical polymerization initiator is used as a gas generator (G), part of the compound functions as both a free radical polymerization initiator and a gas generator (G).

[0073] [Free radical polymerization initiator (RI)] The adhesive may, as needed, contain a radical polymerization initiator (RI) that initiates the polymerization of a free radical polymerizable monomer (M) upon irradiation by an active energy line. When the free radical polymerizable monomer (M) is UV-curable, the adhesive is preferably a radical polymerization initiator (RI) (in this case, the radical polymerization initiator (RI) is also called a photopolymerization initiator).

[0074] There are no particular limitations on the use of acetophenone-based free radical polymerization initiators (RIs), and well-known ones can be used. Examples include: 4-phenoxydichloroacetophenone, 4-tributyl-dichloroacetophenone, diethoxyacetophenone, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropane-1-one, 1-hydroxycyclohexylphenyl ketone, 2-benzyl-2-dimethylamino-1-(4-morpholinylphenyl)-butane-1-one, and 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinylpropane-1-one; benzoin, benzoin... Benzoin-based polymerization initiators such as benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, and benzoin dimethyl ketal; benzophenone-based polymerization initiators such as benzoylbenzoic acid, methyl benzoate, 4-methylbenzophenone, 4-phenylbenzophenone, hydroxybenzophenone, acrylated benzophenone, and 4-benzoyl-4'-methyldiphenyl sulfide; thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, isopropylthioxanthone, and 2,4-dibenzoylbenzoic acid. Isopropyl thioxanthone and other thioxanthone-based polymerization initiators; 2,4,6-trichloro-symmetric triazine, 2-phenyl-4,6-bis(trichloromethyl)-symmetric triazine, 2-(p-methoxyphenyl)-4,6-bis(trichloromethyl)-symmetric triazine, 2-(p-tolyl)-4,6-bis(trichloromethyl)-symmetric triazine, 2-piperyl-4,6-bis(trichloromethyl)-symmetric triazine, 2,4-bis(trichloromethyl)-6-styryl-symmetric triazine, 2- Triazine polymerization initiators, such as (naphthyl-1-yl)-4,6-bis(trichloromethyl)-symmetric triazine, 2-(4-methoxy-naphthyl-1-yl)-4,6-bis(trichloromethyl)-symmetric triazine, 2,4-trichloromethyl-(piperyl)-6-triazine, and 2,4-trichloromethyl(4'-methoxystyryl)-6-triazine; phosphine oxide polymerization initiators; borate ester polymerization initiators; carbamate polymerization initiators; and imidazole polymerization initiators, etc. One or more of these may be used. Some of the free radical polymerization initiators (RI) exemplified can also function as gas generators (G). There are no particular restrictions on the amount of free radical polymerization initiator (RI) in the adhesive layer, for example, it is about 0.5% to 1.5% by mass.

[0075] [Sensenizer (RS)] The adhesive may, as needed, contain one or more sensitizers (RS). The sensitizers (RS) can absorb active energy lines such as ultraviolet light and electron beams, and provide the energy obtained therefrom to other substances to promote polymerization reactions. As sensitizers (RS), known compounds can be used, such as: dibenzopiperanol pigments, coumarin pigments, 3-ketocoumarin compounds, and pyrromethene pigments; dialkylaminobenzoic acid compounds such as ethyl 4-dimethylaminobenzoate and 2-ethylhexyl 4-dimethylaminobenzoate; and thiol hydrogen donors such as 2-mercaptobenzothiazole, 2-mercaptobenzoxazole, and 2-mercaptobenzimidazole. One or more of these can be used.

[0076] When the adhesive layer contains a sensitizer (RS), it can enhance the reactivity of free radical polymerization caused by irradiation with the active energy line, effectively reducing the UV transmittance of the adhesive layer. However, if too much is added, the reactivity of the adhesive layer may become excessively high, making it easier to initiate and proceed with reactions from the small amounts of ultraviolet light contained in ambient light such as fluorescent lamps and sunlight, potentially reducing the adhesive strength of the adhesive layer. When using a sensitizer (RS), it is preferable to use a small amount within a range where free radical polymerization does not occur before irradiation with the active energy line.

[0077] [Plasticizer (P)] From the viewpoint of reducing the adhesion of the adhesive layer and improving wettability and spreadability, the adhesive may further contain one or more plasticizers (P) as needed. The "plasticizer" mentioned here is generally a known plasticizer added to the adhesive to improve wettability and spreadability, and is a material that does not have active energy line curing properties. There are no particular limitations on the plasticizer (P), but from the viewpoint of compatibility with other components, organic acid esters are preferred.

[0078] Examples of esters of monocarboxylic or polycarboxylic acids and alcohols include: isostearyl laurate, isopropyl myristate, isoctyl myristate, octyl dodecyl myristate, isostearyl palmitate, isoctyl stearate, octyl dodecyl oleate, dibutyl phthalate, dioctyl phthalate, diheptyl phthalate, dibenzyl phthalate, butyl benzyl phthalate, diisodecyl adipate, diisostearyl adipate, dibutyl sebacate, diisoceryl sebacate, tributyl acetyl citrate, tributyl trimellitate, trioctyl trimellitate, trihexyl trimellitate, trioleyl trimellitate, and triisoceryl trimellitate.

[0079] Other examples of esters of acids and alcohols include: esters of unsaturated fatty acids or branched acids such as myristenoic acid, oleic acid, linoleic acid, linolenic acid, isopalmitic acid, and isostearic acid with alcohols such as ethylene glycol, propylene glycol, glycerol, trimethylolpropane, neopentyl tertrol, and sorbitan.

[0080] Examples of esters of monocarboxylic acids or polycarboxylic acids with polyalkylene glycols include: polyethylene glycol dihexanoate, polyethylene glycol di-2-ethylhexanoate, polyethylene glycol dilaurate, polyethylene glycol dioleate, and polyethylene glycol dimethyl ether adipate.

[0081] From the perspective of improving wettability and diffusion, the molecular weight (formula weight or Mn) of the organic ester is preferably 250 to 1,000, more preferably 400 to 900, and even more preferably 500 to 850. If the molecular weight is above 250, the heat resistance of the adhesive layer becomes better, and if the molecular weight is below 1,000, the wettability and diffusion of the adhesive become better.

[0082] The adhesive may also be free of plasticizer (P). In this invention, even without adding plasticizer (P) to the adhesive, sometimes one or more free radical polymerizable monomers (M) can function as plasticizers.

[0083] [solvent] The adhesive may contain one or more solvents as needed. Known solvents include methyl ethyl ketone, ethyl acetate, toluene, xylene, and acetone. From the viewpoint of the solubility of hydroxyl-terminated carbamate prepolymers (UPH) and the boiling point of the solvent, ethyl acetate and toluene are particularly preferred.

[0084] [Anti-deterioration agent] Adhesives may contain one or more anti-deterioration agents as needed. This helps to suppress the degradation of various properties of the adhesive layer due to long-term use. Examples of anti-deterioration agents include: hydrolysis resistant agents, antioxidants, ultraviolet absorbers, and light stabilizers.

[0085] [Hydrolysis resistant agent] When hydrolysis occurs in the adhesive layer under (humid) heat conditions, resulting in the formation of carboxyl groups, a hydrolysis-resistant agent can be used to block these carboxyl groups. Examples of hydrolysis-resistant agents include carbodiimide-based, oxazoline-based, and epoxy-based agents. Among these, carbodiimide-based agents are preferred from the viewpoint of inhibiting hydrolysis.

[0086] Carbodiimidine hydrolysis inhibitors are compounds having one or more carbodiimidine groups. Examples of monocarbodiamide compounds include: dicyclohexylcarbodiamide, diisopropylcarbodiamide, dimethylcarbodiamide, diisobutylcarbodiamide, dioctylcarbodiamide, diphenylcarbodiamide, and naphthylcarbodiamide. Polycarbodiimide compounds can be generated by the decarbonation condensation reaction of diisocyanates in the presence of a carbodiimide catalyst. Examples of diisocyanates include: 4,4'-diphenylmethane diisocyanate, 3,3'-dimethoxy-4,4'-diphenylmethane diisocyanate, 3,3'-dimethyl-4,4'-diphenylmethane diisocyanate, 4,4'-diphenyl ether diisocyanate, 3,3'-dimethyl-4,4'-diphenyl ether diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 1-methoxyphenyl-2,4-diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, and tetramethylxylene diisocyanate. Examples of carbodiimide catalysts include: 1-phenyl-2-phosphacyclopentadiene-1-oxide, 3-methyl-2-phosphacyclopentadiene-1-oxide, 1-ethyl-3-methyl-2-phosphacyclopentadiene-1-oxide, 1-ethyl-2-phosphacyclopentadiene-1-oxide and their 3-phosphacyclopentadiene isomers, etc.

[0087] Examples of oxazoline hydrolysis inhibitors include: 2,2'-o-phenylbis(2-oxazoline), 2,2'-m-phenylbis(2-oxazoline), 2,2'-p-phenylbis(2-oxazoline), 2,2'-p-phenylbis(4-methyl-2-oxazoline), 2,2'-m-phenylbis(4-methyl-2-oxazoline), and 2,2'-p-phenylbis(4,4'-dimethyl-2-oxazoline). Examples of oxazoline include 2,2'-m-phenylbis(4,4'-dimethyl-2-oxazoline), 2,2'-ethylbis(2-oxazoline), 2,2'-tetramethylenebis(2-oxazoline), 2,2'-hexamethylenebis(2-oxazoline), 2,2'-octamethylenebis(2-oxazoline), 2,2'-ethylbis(4-methyl-2-oxazoline), and 2,2'-diphenylbis(2-oxazoline).

[0088] Examples of epoxy-based hydrolysants include: diglycidyl ethers of aliphatic diols such as 1,6-hexanediol, neopentyl glycol, and polyalkylene glycol; polyglycidyl ethers of aliphatic polyols such as sorbitol, sorbitan, polyglycerol, neopentyl tert-ol, diglycerol, glycerol, and trimethylolpropane; polyglycidyl ethers of alicyclic polyols such as cyclohexanediol; diglycidyl esters or polyglycidyl esters of aliphatic or aromatic polycarboxylic acids such as terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, trimellitic acid, adipic acid, and sebacic acid; resorcinol, bis-(p-hydroxyphenyl)methane, and 2,2-bis-(p-hydroxyphenyl)methane. Diglycidyl ethers or polyglycidyl ethers of polyphenols such as hydroxyphenyl propane, tri-(p-hydroxyphenyl)methane, and 1,1,2,2-tetra(p-hydroxyphenyl)ethane; N-glycidyl derivatives of amines such as N,N-diglycidyl aniline, N,N-diglycidyl toluidine, and N,N,N',N'-tetraglycidyl-bis-(p-aminophenyl)methane; triglycidyl derivatives of aminophenols; triglycidyl tris(2-hydroxyethyl)isocyanurate and triglycidyl isocyanurate; o-cresol type epoxy resins and phenolic varnish type epoxy resins, etc.

[0089] There is no particular limitation on the amount of hydrolysis resistant agent added. It is more preferably 0.1 to 5 parts by weight, more preferably 0.2 to 4.5 parts by weight, and even more preferably 0.5 to 3 parts by weight, relative to 100 parts by weight of the compound (HC) containing active hydrogen groups (preferably hydroxyl-terminated aminocarbamate prepolymer (UPH)).

[0090] [Antioxidants] Examples of antioxidants include free radical scavengers and peroxide decomposers. Examples of free radical scavengers include phenolic compounds and amine compounds. Examples of peroxide decomposers include sulfur compounds and phosphorus compounds.

[0091] Examples of phenolic compounds include: 2,6-di-tertiary butyl-p-cresol, butylated hydroxyanisole, 2,6-di-tertiary butyl-4-ethylphenol, stearyl-(3,5-di-tertiary butyl-4-hydroxyphenyl)propionate, 2,2'-methylenebis(4-methyl-6-tertiary butylphenol), 2,2'-methylenebis(4-ethyl-6-tertiary butylphenol), 4,4'-thiobis(3-methyl-6-tertiary butylphenol), 4,4'-butylenebis(3-methyl-6-tertiary butylphenol), 3,9-bis[1,1-dimethyl-2-[β-(3-tertiary butyl-4-hydroxy-5-methylphenyl)propoxy]ethyl]2,4,8,10-tetraoxazolo[5, [5] Undecane, phenylpropionic acid, 3,5-bis(1,1-dimethylethyl)-4-hydroxy-,C7-C9 side-chain alkyl ester, 1,1,3-tris(2-methyl-4-hydroxy-5-tertiary butylphenyl)butane, 1,3,5-trimethyl-2,4,6-tris(3,5-di-tertiary butyl-4-hydroxybenzyl)benzene, tetra-[methylene-3-(3',5'-di-tertiary butyl-4'-hydroxyphenyl)propionate]methane, bis[3,3'-bis-(4'-hydroxy-3'-tertiary butylphenyl)butyrate]diol ester, 1,3,5-tris(3',5'-di-tertiary butyl-4'-hydroxybenzyl)-symmetric triazine-2,4,6-(1H,3H,5H)trione, and tocopherol, etc.

[0092] Examples of sulfur-based antioxidants include: dilaurate 3,3'-thiodipropionate, dimyristyl 3,3'-thiodipropionate, and distearate 3,3'-thiodipropionate.

[0093] Examples of phosphorus compounds include: triphenyl phosphite, diphenyl isodecanite, 4,4'-butylene-bis(3-methyl-6-tert-butylphenyl di(tetrazyl)) phosphite, cyclopentanetetramethylbis(octadecyl phosphite), tri(nonylphenyl) phosphite, tri(mononylphenyl) phosphite, tri(dinonylphenyl) phosphite, diisodecylneoptertyl phosphite, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, and 10-(3,5-diphenyl)phosphite. -Tributyl-4-hydroxybenzyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 10-decoxy-9,10-dihydro-9-oxa-10-phosphaphenanthrene, tris(2,4-di-tert-butylphenyl) phosphite, cyclopentanetetramethylbis(2,4-di-tert-butylphenyl) phosphite, cyclopentanetetramethylbis(2,6-di-tert-butyl-4-methylphenyl) phosphite, and 2,2-methylenebis(4,6-di-tert-butylphenyl) octyl phosphite, etc.

[0094] By using antioxidants, the thermal degradation of hydroxyl-terminated carbamate prepolymers (UPH) can be prevented. There is no particular limitation on the amount of antioxidant added, but it is more preferably 0.01 to 5 parts by weight, more preferably 0.1 to 3 parts by weight, and even more preferably 0.2 to 2 parts by weight, relative to 100 parts by weight of the compound (HC) containing active hydrogen groups (preferably hydroxyl-terminated aminocarbamate prepolymer (UPH)).

[0095] From the viewpoint of stability and antioxidant effect, it is preferable to use one or more phenolic compounds as free radical scavengers, and more preferably to use one or more phenolic compounds as free radical scavengers and one or more phosphorus compounds as peroxide decomposers. Furthermore, it is particularly preferable to use phenolic compounds as free radical scavengers and phosphorus compounds as peroxide decomposers in combination as antioxidants, and to use these antioxidants in combination with the aforementioned hydrolysis-resistant agents.

[0096] UV absorber Examples of ultraviolet absorbers include: benzophenone compounds, benzotriazole compounds, salicylic acid compounds, oxalic acid aniline compounds, cyanoacrylate compounds, and triazine compounds. The amount of ultraviolet absorber added can be appropriately designed within the following range: it does not hinder the initiation and progress of the polymerization of free radical polymerizable monomers (M) caused by irradiation with active energy rays, and it does not easily initiate the reaction of free radical polymerizable monomers (M) due to ambient light such as fluorescent lamps and sunlight. When the free radical polymerizable monomer (M) is UV-curable, the amount of ultraviolet absorber added is designed according to the type of ultraviolet absorber, the wavelength range of ultraviolet light irradiating the adhesive layer, and the cumulative light intensity. Relative to 100 parts by weight of the compound (HC) containing active hydrogen groups (preferably a hydroxyl-terminated aminocarbamate prepolymer (UPH)), the amount of ultraviolet absorber added is preferably 0.01 parts by weight to 3 parts by weight, more preferably 0.1 parts by weight to 2.5 parts by weight, and even more preferably 0.2 parts by weight to 2 parts by weight.

[0097] [Light stabilizer] Examples of light stabilizers include hindered amine compounds and hindered piperidine compounds. There are no particular limitations on the amount of light stabilizer added, but it is preferably 0.01 to 2 parts by weight, more preferably 0.1 to 1.5 parts by weight, and even more preferably 0.2 to 1 part by weight, relative to 100 parts by weight of the compound (HC) containing an active hydrogen group (preferably a hydroxyl-terminated aminocarbamate prepolymer (UPH)).

[0098] [Antistatic agent (AS)] The adhesive may contain one or more antistatic agents (AS) as needed. Examples of antistatic agents (AS) include inorganic salts, ionic liquids, ionic solids, and surfactants, with ionic liquids and ionic solids being preferred. Furthermore, "ionic liquids" are also known as molten salts at room temperature, which are salts that are fluid at 25°C.

[0099] Examples of inorganic salts include: sodium chloride, potassium chloride, lithium chloride, lithium perchlorate, ammonium chloride, potassium chlorate, aluminum chloride, copper chloride, ferrous chloride, ferric chloride, ammonium sulfate, potassium nitrate, sodium nitrate, sodium carbonate, and sodium thiocyanate.

[0100] Examples of ionic liquids containing imidazolium ions include 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonium)imine, 1,3-dimethylimidazolium bis(trifluoromethylsulfonium)imine, and 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonium)imine.

[0101] Examples of ionic liquids containing pyridinium ions include: 1-methylpyridinium bis(trifluoromethylsulfonium)imine, 1-butylpyridinium bis(trifluoromethylsulfonium)imine, 1-hexylpyridinium bis(trifluoromethylsulfonium)imine, 1-octylpyridinium bis(trifluoromethylsulfonium)imine, 1-hexyl-4-methylpyridinium bis(trifluoromethylsulfonium)imine, 1-hexyl-4-methylpyridinium hexafluorophosphate, 1-octyl-4-methylpyridinium bis(trifluoromethylsulfonium)imine, 1-octyl-4-methylpyridinium bis(fluorosulfonium)imine, 1-methylpyridinium bis(perfluoroethylsulfonium)imine, and 1-methylpyridinium bis(perfluorobutylsulfonium)imine.

[0102] Examples of ionic liquids containing ammonium ions include: 1-butyl-3-methylpyridinium bis(trifluoromethanesulfonyl)imine, trimethylheptylammonium bis(trifluoromethanesulfonyl)imine, N,N-diethyl-N-methyl-N-propylammonium bis(trifluoromethanesulfonyl)imine, N,N-diethyl-N-methyl-N-pentylammonium bis(trifluoromethanesulfonyl)imine, N,N-diethyl-N-methyl-N-heptylammonium bis(trifluoromethanesulfonyl)imine, and tri-n-butylmethylammonium bis(trifluoromethanesulfonyl)imine.

[0103] In addition, commercially available ionic liquids such as pyrrolidine onium salts, phosphonium salts, and strontium salts can be used appropriately.

[0104] Ionic solids, like ionic liquids, are salts of cations and anions, but they exhibit solid properties at ambient pressure and 25°C. Preferred cations include alkali metal ions, phosphonium ions, pyridinium ions, and ammonium ions.

[0105] Examples of ionic solids containing alkali metal ions include: lithium difluorosulfonylimide, lithium ditrifluoromethylsulfonylimide, lithium dipentafluoroethylsulfonylimide, lithium diheptafluoropropylsulfonylimide, lithium dinonafluorobutylsulfonylimide, sodium difluorosulfonylimide, sodium ditrifluoromethylsulfonylimide, sodium dipentafluoroethylsulfonylimide, sodium diheptafluoropropylsulfonylimide, sodium dinonafluorobutylsulfonylimide, potassium difluorosulfonylimide, potassium ditrifluoromethylsulfonylimide, potassium dipentafluoroethylsulfonylimide, potassium diheptafluoropropylsulfonylimide, and potassium dinonafluorobutylsulfonylimide.

[0106] Examples of ionic solids containing phosphonium ions include: tetrabutylphosphonium difluorosulfonyl imide, tetrabutylphosphonium ditrifluoromethylsulfonyl imide, tetrabutylphosphonium dipentafluoroethylsulfonyl imide, tetrabutylphosphonium diheptafluoropropylsulfonyl imide, tetrabutylphosphonium dinonafluorobutylsulfonyl imide, tributylhexadecylphosphonium difluorosulfonyl imide, tributylhexadecylphosphonium ditrifluoromethylsulfonyl imide, and tributylphosphonium difluoromethylsulfonyl imide. Butylhexadecylphosphonium bispentafluoroethyl sulfonylimide, tributylhexadecylphosphonium bisheptafluoropropyl sulfonylimide, tributylhexadecylphosphonium bisnonafluorobutyl sulfonylimide, tetraoctylphosphonium bisfluorosulfonylimide, tetraoctylphosphonium bistrifluoromethyl sulfonylimide, tetraoctylphosphonium bispentafluoroethyl sulfonylimide, tetraoctylphosphonium bisheptafluoropropyl sulfonylimide, and tetraoctylphosphonium bisnonafluorobutyl sulfonylimide, etc.

[0107] Examples of ionic solids containing pyridinium ions include: 1-hexadecyl-4-methylpyridinium difluorosulfonylimide, 1-hexadecyl-4-methylpyridinium ditrifluoromethylsulfonylimide, 1-hexadecyl-4-methylpyridinium dipentafluoroethylsulfonylimide, 1-hexadecyl-4-methylpyridinium diheptafluoropropylsulfonylimide, and 1-hexadecyl-4-methylpyridinium dinonafluorobutylsulfonylimide.

[0108] Examples of ionic solids containing ammonium ions include: lauryltrimethylammonium chloride, tributylmethylbis(trifluoromethyl)sulfonylimide, tributylmethylbis(pentafluoroethyl)sulfonylimide, tributylmethylbis(heptafluoropropyl)sulfonylimide, tributylmethylbis(nonafluorobutyl)sulfonylimide, octyltributylbis(trifluoromethyl)sulfonylimide, octyltributylbis(pentafluoroethyl)sulfonylimide, octyltributylbis(heptafluoropropyl)sulfonylimide, octyltributylbis(nonafluorobutyl)sulfonylimide, tetrabutylbis(fluoromethyl)sulfonylimide, tetrabutylbis(pentafluoroethyl)sulfonylimide, tetrabutylbis(heptafluoropropyl)sulfonylimide, and tetrabutylbis(nonafluorobutyl)sulfonylimide.

[0109] In addition, known ionic solids with cations such as pyrrolidone, imidazolium, and strontium can be used appropriately.

[0110] As surfactants, nonionic surfactants and anionic surfactants can be listed, and each type can be classified as low molecular weight surfactants and high molecular weight surfactants.

[0111] Examples of nonionic, low-molecular-weight surfactants include: glycerol fatty acid esters, polyoxyethylene alkyl ethers, polyoxyethylene ethyl alkylphenyl ethers, polyoxyethylene ethyl alkylamines, polyoxyethylene ethyl alkylamine fatty acid esters, and fatty acid diethanolamides. Examples of anionic low-molecular-weight surfactants include alkyl sulfonates, alkylbenzene sulfonates, and alkyl phosphates. Examples of amphoteric low-molecular-weight surfactants include alkyl betaine and alkyl imidazoline betaine.

[0112] Examples of nonionic polymeric surfactants include polyether ester amide type, ethylene oxide-epimerol type, and polyether ester type. Examples of anionic polymeric surfactants include polystyrene sulfonate type. Examples of amphoteric polymeric surfactants include: amino acid-type amphoteric surfactants such as higher alkylaminopropionates, and betaine-type amphoteric surfactants such as higher alkyl dimethyl betaine and higher alkyl dihydroxyethyl betaine.

[0113] The amount of antistatic agent (AS) added is preferably 0.01 to 10 parts by mass relative to 100 parts by mass of compound (HC) containing active hydrogen groups, and more preferably 0.03 to 5 parts by mass.

[0114] [Leveling agent] The adhesive may contain a leveling agent as needed. By adding a leveling agent, the leveling properties of the adhesive layer can be improved. Examples of leveling agents include acrylic leveling agents, fluorinated leveling agents, and polysiloxane leveling agents. From the viewpoint of suppressing contamination of the adhered body after the adhesive sheet is peeled off, acrylic leveling agents are preferred.

[0115] There is no particular limitation on the amount of leveling agent added. From the viewpoint of inhibiting contamination of the adhered body after the adhesive sheet is peeled off and improving the leveling properties of the adhesive layer, the amount of the compound (HC) containing active hydrogen groups (preferably hydroxyl-terminated amino carbamate prepolymer (UPH)) is preferably 0.001 to 2 parts by weight, more preferably 0.01 to 1.5 parts by weight, and even more preferably 0.1 to 1 part by weight, relative to 100 parts by weight.

[0116] [Any other ingredients] The adhesive may contain any other ingredients as needed, without impairing the effectiveness of the invention. Examples of such other ingredients include: catalysts, resins other than urethane resins, fillers (talc, calcium carbonate, and titanium dioxide, etc.), metal powders, colorants (pigments, etc.), foils, softeners, conductive agents, silane coupling agents, lubricants, corrosion inhibitors, heat stabilizers, weather stabilizers, polymerization inhibitors, and defoamers. When the adhesive contains a catalyst, it is preferable to add a known catalyst inhibitor such as acetone to improve the adhesive's pot life.

[0117] [Blending ratio] The adhesive comprises: one or more non-radical polymerizable compounds containing active hydrogen groups (HC), having multiple active hydrogen groups and not having (meth)acrylic groups; one or more radical polymerizable monomers (M), including one or more radical polymerizable monomers containing active hydrogen groups (MH), wherein the aforementioned one or more radical polymerizable monomers containing active hydrogen groups (MH) have one or more active hydrogen groups and two or more (meth)acrylic groups; a polyfunctional isocyanate compound (I); and a gas generator (G). There are no particular restrictions on the mixing ratio of these ingredients, but the optimal mixing ratio is as follows.

[0118] Relative to 100 parts by weight of one or more compounds containing active hydrogen groups (HC) (preferably one or more hydroxyl-terminated aminocarbamate prepolymers (UPH)), the amount of one or more polyfunctional isocyanate compounds (I) is preferably 1 to 40 parts by weight, more preferably 3 to 40 parts by weight, and even more preferably 5 to 35 parts by weight. If the amount of one or more polyfunctional isocyanate compounds (I) is 1 part by weight or more, the cohesiveness of the adhesive layer becomes better; if it is 40 parts by weight or less, the pot life becomes better.

[0119] From the perspective of adhesion before irradiation by active energy lines, the amount of one or more free radical polymerizable monomers containing active hydrogen groups (MH) is preferably 2 to 150 parts by mass, more preferably 2 to 95 parts by mass, even more preferably 2 to 50 parts by mass, and most preferably 2 to 35 parts by mass, relative to 100 parts by mass of one or more compounds containing active hydrogen groups (HC) (preferably one or more hydroxyl-terminated aminocarbamate prepolymers (UPH)). From the perspective of reducing wetting and diffusivity by irradiating active energy lines, the amount of one or more free-radical polymerizable monomers (MH) containing active hydrogen groups (preferably one or more hydroxyl-terminated carbamate prepolymers (UPH)) per 100 parts by mass is preferably 2 to 150 parts by mass, more preferably 10 to 140 parts by mass, particularly preferably 30 to 130 parts by mass, and most preferably 50 to 120 parts by mass. From the perspective of balancing the above two performance requirements, the amount of one or more free-radical polymerizable monomers (MH) containing active hydrogen groups (preferably one or more hydroxyl-terminated carbamate prepolymers (UPH)) per 100 parts by mass is preferably 2 to 150 parts by mass, more preferably 10 to 95 parts by mass, and most preferably 30 to 50 parts by mass. In cases where more emphasis is placed on one of the two performance requirements mentioned above, the amount of one or more free radical polymerizable monomers (MH) containing active hydrogen groups can be designed according to the performance valued.

[0120] As described above, the one or more free radical polymerizable monomers (M) may, as needed, contain one or more other free radical polymerizable monomers (MO) besides the monomer (MH) containing an active hydrogen group. The amount of the one or more free radical polymerizable monomers (M) is preferably 10 to 150 parts by mass, and more preferably 30 to 100 parts by mass, relative to 100 parts by mass of the compound (HC) containing an active hydrogen group (preferably one or more hydroxyl-terminated aminocarbamate prepolymers (UPH)).

[0121] From the perspective of improving the peelability by irradiating active energy lines, the content of gas generator (G) in the adhesive layer is preferably 2% by mass or more, more preferably 3% to 30% by mass, and even more preferably 5% to 20% by mass.

[0122] [Manufacturing method of adhesive] There are no particular restrictions on the manufacturing method of adhesive. Prepare one or more compounds (HC) containing active hydrogen groups, preferably one or more hydroxyl-terminated carbamate prepolymers (UPH) synthesized by the above method. The hydroxyl-terminated carbamate prepolymer (UPH) may also be in the form of a solution containing a solvent. An adhesive can be manufactured by adding one or more free radical polymerizable monomers (M) containing one or more free radical polymerizable monomers (MH) having one or more active hydrogen groups and two or more (meth)acrylic groups, a polyfunctional isocyanate compound (I), a gas generator (G), and one or more other arbitrary components as needed to one or more of the above-mentioned compounds (HC) containing active hydrogen groups (preferably one or more hydroxyl-terminated aminocarbamate prepolymers (UPH)).

[0123] [Adhesive sheet] The adhesive sheet of the present invention comprises: a substrate sheet; and an adhesive layer formed on at least one side of the substrate sheet. The adhesive layer is composed of a dried coating of the aforementioned adhesive and has active energy line curing properties. If necessary, the exposed surface of the adhesive layer may be covered by a release liner. Furthermore, the release liner is peeled off before the adhesive sheet is attached to the substrate.

[0124] Figure 1 shows a schematic cross-sectional view of the adhesive sheet according to the first embodiment of the present invention. In Figure 1, symbol 10 is the adhesive sheet, symbol 11 is the substrate sheet, symbol 12 is the adhesive layer, and symbol 13 is the release liner. The adhesive sheet 10 is a single-sided adhesive sheet in which an adhesive layer is formed on one side of the substrate sheet. Figure 2 shows a schematic cross-sectional view of the adhesive sheet according to the second embodiment of the present invention. In Figure 2, symbol 20 is the adhesive sheet, symbol 21 is the substrate sheet, symbols 22A and 22B are adhesive layers, and symbols 23A and 23B are release sheets. The adhesive sheet 20 is a double-sided adhesive sheet with adhesive layers formed on both sides of the substrate sheet.

[0125] There are no particular limitations on the substrate material; examples include resin sheets, paper, and metal foil. The substrate material can also be a laminate with any one or more layers in at least one area layer of these substrate materials. Furthermore, the surfaces of the substrate material forming the adhesive layer can be treated with corona discharge and primer coating, etc., as needed, to facilitate adhesion.

[0126] There are no particular limitations on the resins that can be used to make resin sheets. Examples include: ester resins such as polyethylene terephthalate (PET); olefin resins such as polyethylene (PE) and polypropylene (PP); ethylene resins such as polyvinyl chloride; amide resins such as nylon 66; carbamate resins (including foams); and combinations thereof. There are no particular limitations on the thickness of resin sheets other than polyurethane sheets, but it is preferably from 15 μm to 300 μm. There are no particular limitations on the thickness of polyurethane sheets (including foam), but it is preferably from 20 μm to 50,000 μm.

[0127] There are no particular restrictions on the type of paper; examples include ordinary paper, coated paper, and art paper. There are no particular restrictions on the metals that can be used to make up metal foil; examples include aluminum, copper, and combinations thereof.

[0128] There are no particular restrictions on the release sheet used; any known release sheet that has undergone a known release treatment, such as coating a release agent on the surface of a substrate sheet, such as a resin sheet or paper sheet, can be used.

[0129] There are no particular limitations on the thickness of the adhesive layer, which can be appropriately designed according to the application. For applications such as surface protectants, a thickness of 0.1 μm to 200 μm is preferred, more preferably 30 μm to 200 μm, even more preferably 50 μm to 200 μm, and most preferably 75 μm to 150 μm is preferred. If the thickness of the adhesive layer is within the above range, it is easy to obtain an adhesive sheet that has sufficient transparency and good UV transmittance as a surface protection sheet for LCD and other panel displays and touch panel displays, as well as substrates and optical components manufactured or used in their manufacturing process.

[0130] [Manufacturing Method of Adhesive Sheets] The adhesive sheet can be manufactured using known methods. First, an adhesive is applied to the surface of the substrate to form a coating layer composed of the adhesive. Known coating methods can be used, including: roller coating, comma coating, die coating, reverse coating, screen coating, and gravure coating. The coating is then heated and dried to form an adhesive layer. There are no particular limitations on the heating and drying temperature, but it is preferably between 60°C and 150°C. The thickness of the adhesive layer (after drying) can be appropriately designed within a range that provides optimal transparency and UV transmittance, depending on the application. Subsequently, a release liner is attached to the exposed surface of the adhesive layer using known methods, as needed. As described above, single-sided adhesive sheets can be manufactured. By performing the above operations on both sides, a double-sided adhesive sheet can be manufactured.

[0131] Alternatively, the method described above can be reversed by applying an adhesive to the surface of the release sheet to form a coating layer composed of adhesive. The coating layer is then heated and dried to form an adhesive layer, and the substrate sheet is exposed on the surface of the adhesive layer.

[0132] The preferred method for manufacturing the adhesive sheet includes: a coating step, in which an adhesive is applied to a substrate sheet; a heating step, in which the coating layer is heated and dried to form an adhesive layer; a winding step, in which the obtained adhesive sheet is wound onto a core to form an adhesive sheet roll; and a curing step, in which the adhesive sheet roll is cured.

[0133] After the adhesive is prepared, a reaction is carried out with one or more non-radical polymerizable compounds containing active hydrogen groups (HC), one or more free radical polymerizable monomers containing active hydrogen groups having one or more active hydrogen groups and two or more (meth)acrylic groups (MH), and a polyfunctional isocyanate compound (I). The adhesive layer of the adhesive sheet contains these reaction products.

[0134] [UV transmittance] When the free radical polymerizable monomer (M) is UV-curable, the adhesive sheet of the present invention preferably has moderate UV transmittance. In this specification, the transmittance at a wavelength of 365 nm is defined as "UV transmittance". "UV transmittance" can be measured using the method described in the [Examples] section below. The adhesive layer of the adhesive sheet of the present invention absorbs ultraviolet light and converts the absorbed ultraviolet light into energy for free radical polymerization and foaming. Therefore, it preferably has a low UV transmittance. From this perspective, the UV transmittance of the adhesive sheet of the present invention is preferably 82% or less, more preferably 81% or less, particularly preferably 79% or less, and most preferably 75% or less. When the substrate is irradiated with ultraviolet light from one side onto the adherend having the adhesive sheet, it is preferable that the ultraviolet light reaches the contact interface between the adhesive layer and the adherend. From this perspective, the UV transmittance of the adhesive sheet of the present invention is preferably 1% or more, more preferably 10% or more, and particularly preferably 20% or more.

[0135] UV transmittance varies depending on the type (chemical structure) and amount of gas generator (G), the type (chemical structure) and amount of sensitizer (RS), and the thickness of the adhesive layer. It is preferable to adjust these conditions so that the UV transmittance is below 82%. In this invention, by having an adhesive layer containing a gas generator (G) that absorbs ultraviolet light and a sensitizer (RS) that absorbs ultraviolet light as needed, the UV transmittance can be effectively reduced.

[0136] [Haze] When the adhesive sheet of the present invention is used as a surface protective film for LCD panel displays and touch panel displays, as well as substrates and optical components manufactured or used in the manufacturing process of these, it is preferably highly transparent. As an indicator of transparency, "haze value" can be listed. The haze value of the adhesive sheet of the present invention is not particularly limited, but is preferably 3 or less, more preferably 2 or less. The haze value can be measured, for example, according to JIS-K7136.

[0137] [How to use adhesive pads] The method of using the first adhesive sheet of the present invention includes the following steps: attaching the adhesive sheet of the present invention to the surface of the object to be adhered; and irradiating the adhesive sheet attached to the surface of the object with active energy lines such as ultraviolet light and electron beams to reduce the adhesive force of the adhesive sheet.

[0138] The method of using the second adhesive sheet of the present invention includes the following steps: attaching the adhesive sheet to the surface of the adherend; and irradiating the adhesive sheet of the present invention attached to the surface of the adherend with active energy lines to reduce the adhesive force of the adhesive sheet, so that the self-weight adhesion time of the adhesive layer to the acrylic resin board after irradiation by the method described later is more than 30 seconds, and the adhesive sheet with reduced adhesive force is peeled off from the adherend.

[0139] In the manufacturing processes of liquid crystal displays (LCDs), organic light-emitting diode displays (OLEDs), and touch panel displays, to improve productivity, it is preferable to be able to transport the adhered body with adhesive sheet at high speed to the processing unit where necessary steps are performed. For example, the following automated high-speed transport is being studied: using a vacuum adsorption member, the adhered body with adhesive sheet is adsorbed from the adhesive sheet side, the adhered body with adhesive sheet is lifted and transported to the required location. In this automated high-speed transport, the adhered body with adhesive sheet preferably has sufficient adhesive force to prevent the adhesive sheet from peeling off from the adhered body during adsorption by the vacuum adsorption member. On the other hand, for the adhered body with adhesive sheet after the necessary steps have been completed, it is preferable that the adhesive sheet has relatively low adhesive force so that the adhesive sheet can be peeled off at high speed. It is preferable that the adhesive sheet can be easily peeled off from the adhered body with adhesive sheet after the necessary steps have been completed.

[0140] The adhesive layer of the adhesive sheet of the present invention comprises a free radical polymerizable monomer (M) and a gas generator (G) that generates gas upon irradiation by an active energy line. In the adhesive sheet of the present invention, the free radical polymerizable monomer (M) polymerizes upon irradiation by an active energy line, thereby reducing the adhesive strength and wetting diffusion of the adhesive layer, and generating gas from the adhesive layer. These effects work together to enable the adhesive sheet to be easily peeled off from the adherend after irradiation by the active energy line. For example, the adhesive sheet can be easily peeled off from the adherend by means of blowing air, or it can be peeled off naturally from the adherend.

[0141] The adhesion and wetting diffusion properties of the active energy lines of the adhesive layer before and after irradiation can be appropriately designed according to the application and usage conditions. In applications such as the high-speed transport of the adhered object with the adhesive sheet using a vacuum adsorption component, the following design is preferred.

[0142] Before irradiation with active energy lines, the adhesion of the adhesive layer, measured using a tensile testing machine according to JIS Z0237 at a peel speed of 0.3 m / min and a peel angle of 180°, is 0.1 gf / 25 mm or more, preferably 0.5 gf / 25 mm or more, and even more preferably 1.0 gf / 25 mm or more. Before irradiation with active energy lines, the adhesion of the adhesive layer, measured using a tensile testing machine according to JIS Z0237 at a peel speed of 0.3 m / min and a peel angle of 180°, is 26 gf / 25 mm or less, preferably 20 gf / 25 mm or less, and even more preferably 10 gf / 25 mm or less. If the adhesive force of the adhesive layer is above the lower limit, the adhered body with the adhesive sheet can have sufficient adhesive force to prevent the adhesive sheet from peeling off from the adhered body during adsorption on the vacuum adsorption member. If the adhesive force of the adhesive layer is above the lower limit, the adhered body with the adhesive sheet can have sufficient adhesive force so that the adhesive sheet is not easily peeled off from the adhered body due to air blowing. If the adhesive strength of the adhesive layer is below the upper limit, it has good re-peelability before irradiation by the active energy line and can be re-attached.

[0143] There is no particular limitation on the rate of reduction of the adhesive force of the adhesive layer after irradiation with active energy lines relative to the rate before irradiation, but it is preferably less than 2 / 3, more preferably less than 1 / 2, and even more preferably less than 1 / 3.

[0144] "Wet diffusion properties" can be evaluated, for example, by measuring the self-weight adhesion time of an acrylic resin board. In this specification, the "self-weight adhesion time of an acrylic resin board" is measured using the following method. Holding the adhesive sheet 100mm wide and 200mm long at both ends along its long side, bend the sheet with the adhesive layer facing outwards, bringing the two ends together. In this position, bring the adhesive layer in the center of the adhesive sheet into contact with the acrylic resin board. Release both hands from this position. Measure the time from releasing the hands until the adhesive layer is completely adhered to the acrylic resin board; this is called the self-weight adhesion time. An example of an acrylic resin board is the "Acrylite L" manufactured by Mitsubishi Rayon.

[0145] The shorter the adhesion time of the adhesive layer to the acrylic resin board before irradiation by active energy lines, the better the wetting and diffusion properties (affinity to the adherend). Before irradiation with active energy lines, the adhesion time of the adhesive layer to the acrylic resin board by its own weight is preferably less than 15 seconds, more preferably less than 10 seconds, and even more preferably less than 8 seconds. If the adhesion time of the adhesive layer to the acrylic resin board by its own weight is less than 15 seconds, then before irradiation with active energy lines, the adhesive layer has sufficient wetting and spreading properties to the substrate, and can completely adhere the adhesive sheet to the substrate without entraining air bubbles.

[0146] Generally speaking, acrylic adhesive layers have poor wetting and spreading properties, and the adhesion time to the acrylic resin board exceeds 15 seconds. Generally, urethane adhesive layers exhibit excellent wetting and spreading properties, thus the self-weight adhesion time to acrylic resin boards before irradiation with active energy lines is less than 15 seconds. To improve the wetting and spreading properties of urethane adhesive layers, plasticizers (P), free radical polymerizable monomers (M) with alkoxy groups such as ethoxy (EO) and propoxy (PO), or free radical polymerizable monomers (M) with alkyl chains can be used as needed.

[0147] In this invention, the wetting and diffusivity of the adhesive layer can be effectively reduced by irradiating with active energy lines. After irradiation with active energy lines, the self-weight adhesion time of the adhesive layer to the acrylic resin board is preferably 30 seconds or more. If the self-weight adhesion time of the adhesive layer to the acrylic resin board is 30 seconds or more, the re-adhesion of parts that naturally peel off due to gas generation can be effectively suppressed.

[0148] As explained above, according to the present invention, an adhesive sheet based on carbamate can be provided that has good wetting and spreading properties on the adherend before irradiation with active energy lines, has the ability to re-peel the adherend after re-attaching, can adhere the adherend with an adhesive force that is not easy to peel off, and can be easily peeled off from the adherend after irradiation with active energy lines. After being irradiated with active energy lines, the adhesive sheet can be easily detached from the adherend by means of air blowing, or it can be naturally detached from the adherend.

[0149] [use] The adhesive sheet of this invention can be used in the form of tape, standard packaging, sealing, and double-sided tape. The adhesive sheet of this invention is preferably used as a surface protection sheet, cosmetic sheet, and anti-slip sheet. Furthermore, unless otherwise explicitly stated in this instruction manual, "sheet" includes both "film" and "tape". Liquid crystal displays (LCDs) and organic light-emitting diode (OELDs) displays, as well as touch panel displays that combine LCDs with touch panels, are widely used in electronic devices such as televisions (TVs), personal computers (PCs), mobile phones, and mobile information terminals. The adhesive sheet of the present invention can be preferably used as a surface protective sheet for LCD and other panel displays and touch panel displays, as well as substrates (glass substrates and ITO / glass substrates with ITO (indium tin oxide) films formed on glass substrates, etc.) and optical components manufactured or used in these manufacturing steps. [Example]

[0150] The following describes the synthesis examples, embodiments of the present invention, and comparative examples. Furthermore, unless otherwise specified, "parts" refers to parts by mass, "%" refers to %, and "RH" refers to relative humidity. Unless otherwise specified, the unit of the mixing amount in the table is "parts by mass". Unless otherwise specified, the mixing amount of components other than the solvent is the converted value of non-volatile components.

[0151] [Determination of molecular weight] Weight-average molecular weight (Mw) and number-average molecular weight (Mn) were determined by gel permeation chromatography (GPC). The determination conditions are as follows. Furthermore, Mw and Mn are polystyrene equivalents. Apparatus: SHIMADZU Prominence (manufactured by Shimadzu Corporation); Column: Three SHODEX LF-804 (manufactured by Showa Denko Corporation) columns connected in series; Detector: Differential refractive index detector; Solvent: Tetrahydrofuran (THF); Flow rate: 1 mL / min; Solvent temperature: 40 °C; Sample concentration: 0.2%; Sample injection volume: 200 μL.

[0152] [Material] The materials used are as follows. [Compounds containing active hydrogen groups (HX)] (HX-1): Kuraray Polyol P-2010, a polyester polyol with a quantity average molecular weight (Mn) of 2000 and 2 hydroxyl groups, manufactured by Kuraray Corporation; (HX-2): Sannix GP-3000, a polyether polyol with a quantity average molecular weight (Mn) of 3000 and 3 hydroxyl groups, manufactured by Sanyo Chemical Industries Co., Ltd.; (HX-3): Sannix GL-3000, a polyether polyol with a quantity average molecular weight (Mn) of 3000 and 3 hydroxyl groups, manufactured by Sanyo Chemical Industries Co., Ltd.

[0153] [Polyisocyanate (N)] (N-1): Desmodur H, hexamethylene diisocyanate (HDI), manufactured by Sumika Covestro Urethane; (N-2): Desmodur T-80, toluene diisocyanate (TDI), manufactured by Sumika Covestro Urethane.

[0154] [Polyfunctional isocyanate compound (I)] (I-1): Sumidur N3300, cyanurate derivative of hexamethylene diisocyanate, 100% non-volatile component, manufactured by Sumika Covestro Urethane Co., Ltd.; (I-2): Takenate D-110N, trimethylolpropane adduct of xylene diisocyanate, 75% non-volatile component, manufactured by Mitsui Chemicals Co., Ltd.

[0155] [Free radical polymerizable monomers containing active hydrogen groups (M) (Free radical polymerizable monomers containing active hydrogen groups (MH))] (MH-1): MIRAMER M500, dinepentylenetetroxide pentaacrylate, 5 acrylonitrile groups and 1 hydroxyl group, manufactured by MIWON; (MH-2): MIRAMER M340, neopentylenetetroxide triacrylate, 3 acrylonitrile groups and 1 hydroxyl group, manufactured by MIWON.

[0156] [Free radical polymerizable monomer (M) without active hydrogen groups] (MO-3): MIRAMER M600, dinepentylenetetroxide hexaacrylate, 6 acrylonitrile, 0 hydroxyl groups, manufactured by MIWON; (MO-4): MIRAMER M220, tripropylene glycol diacrylate, 2 acrylonitrile, 0 hydroxyl groups, manufactured by MIWON; (MO-5): MIRAMER M202, 1,6-hexanediol ethoxylated diacrylate, 2 acrylonitrile, 0 hydroxyl groups, manufactured by MIWON.

[0157] [Photopolymerization Initiator (RI)] (RI-1): Irgacure TPO, diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide, manufactured by BASF; (RI-2): SB-PI 712, 4-methylbenzophenone, manufactured by Sanyo Trading Co., Ltd.

[0158] [Gas Generator (G)] As gas generating agents (G), prepare (G-18) and (G-14) as listed in Table 1.

[0159] [Sensenizer (RS)] (RS-1): UVS-1331, a compound represented by the following structural formula, manufactured by Kawasaki Chemical Industry Co., Ltd.

[0160] [Plasticizer (P)] (P-1): Tributyl acetate citrate (ATBC), manufactured by Mitsubishi Chemical Corporation.

[0161] [Antioxidant (O)] (O-1): Irganox 1010, a hindered phenolic antioxidant, manufactured by BASF.

[0162] [Antistatic agent (AS)] (AS-1): IL-P14, an ionic liquid, manufactured by Guangrong Chemical Industry Co., Ltd.

[0163] [Example of solution synthesis of hydroxyl-terminated carbamate prepolymer (UPH)] [Synthesis example 1] In a four-necked flask equipped with a stirrer, reflux condenser, nitrogen inlet tube, thermometer, and dropping funnel, 400 parts of a compound containing active hydrogen groups (HX-1), 600 parts of a compound containing active hydrogen groups (HX-2), and 57 parts of polyisocyanate (N-1) were added. 705 parts of toluene, 0.1 parts of dibutyltin dilaurate as a catalyst, and 0.04 parts of tin 2-ethylhexanoate were added and mixed. The contents were gradually heated to 90°C and reacted at 90°C for 2 hours. Sampling was performed continuously, and the reaction was terminated by cooling the reaction solution to 30°C after confirming the disappearance of residual isocyanate groups based on infrared absorption (IR) spectroscopy. As described above, a solution of hydroxyl-terminated carbamate prepolymer (UPH1) with a hydroxyl value of 17.1 mg KOH / g (non-volatile component: 60%) was obtained. The resulting hydroxyl-terminated carbamate prepolymer (UPH1) had a weight average molecular weight (Mw) of 83,000. The formulation composition and the Mw and hydroxyl value of the obtained hydroxyl-terminated carbamate prepolymer are shown in Table 2.

[0164] [Synthesis Examples 2 to 5] In Synthesis Examples 2 to 5, except for changing the type of compound (HX) containing an active hydrogen group, the type of polyisocyanate (N), and their mixing ratios, colorless and transparent solutions of hydroxyl-terminated carbamate prepolymers (UPH-2) to (UPH-5) were obtained, similar to Synthesis Example 1. The formulations and the Mw and hydroxyl values ​​of the resulting hydroxyl-terminated carbamate prepolymers in each synthesis example are shown in Table 2.

[0165] [Table 2] Mn Functional basis Synthesis example 1 Synthesis example 2 Synthesis example 3 Synthesis example 4 Synthesis example 5 UPH1 UPH2 UPH3 UPH4 UPH5 Compounds containing active hydrogen groups (HX) HX-1 Polyester polyols 2000 2 400 200 HX-2 Polyether polyols 3000 3 600 800 1000 HX-3 Polyether polyols 3000 3 1000 1000 Polyisocyanate (N) N-1 HDI 168 2 57 53 49 47 N-3 TDI 174 2 49 Mw (ten thousand) 8.3 14.6 12.1 13.0 13.2 Hydroxyl value [mg / KOH / g] 17.1 19.7 22.3 23.6 23.4

[0166] [Synthesis Example of Acrylic Resin (AR)] [Synthesis Example 21] In a four-necked flask equipped with a stirrer, reflux condenser, nitrogen inlet tube, thermometer, and dropping funnel, 990 parts of n-butyl acrylate, 10 parts of 4-hydroxybutyl acrylate, and 1000 parts of ethyl acetate were added and mixed. The contents were slowly heated to 90°C, and after confirming solvent reflux, 2 parts of azobisisobutyronitrile (AIB) were added and mixed. After 8 hours, the reaction solution was cooled to stop the reaction. As described above, a solution of acrylic resin (AR-1) (non-volatile components: 50%) was obtained. The weight average molecular weight (Mw) of the obtained acrylic resin was 890,000.

[0167] [Manufacturing of adhesives and adhesive sheets] [Example 1] For the solution containing 100 parts of hydroxyl-terminated carbamate prepolymer (UPH1) obtained in Synthesis Example 1, 5 parts of polyfunctional isocyanate compound (I-1), 25 parts of free radical polymerizable monomer containing active hydrogen groups (MH-1), 10 parts of free radical polymerizable monomer without active hydrogen groups (MO-4), 1 part of photopolymerization initiator (RL-1), 1 part of photopolymerization initiator (RL-2), 20 parts of gas generator (G-1), 0.1 parts of antioxidant (O-1), and 0.1 parts of antistatic agent (AS-1) were prepared, and then 80 parts of ethyl acetate were prepared as a solvent. The mixture was stirred using a disperser to obtain a carbamate-based adhesive. In addition, the amounts of materials other than the solvent are expressed as the amount of non-volatile components (the same applies to other examples and comparative examples). As the substrate, a 75 μm thick polyethylene terephthalate sheet (double-sided easy-adhesive PET sheet, Cosmoshine A-4300, manufactured by Toyobo Co., Ltd.) was prepared. The obtained adhesive was applied to one side of this substrate and dried at 100°C for 5 minutes to form a 75 μm thick adhesive layer. A 38 μm thick release liner (Superstec SP-PET38, manufactured by Lintec Co., Ltd.) was then attached to this adhesive layer to obtain the adhesive sheet. After curing for 1 week at 23°C-50%RH, it was used for various evaluations. The formulation composition of the adhesive, the thickness of the adhesive layer, and the evaluation results are shown in Tables 3 and 7. In addition, in the examples in Tables 3 to 6, the conditions not recorded in the tables are set as common conditions.

[0168] [Examples 2 to 27, Comparative Examples 1 to 6] In Examples 2 to 27 and Comparative Examples 1 to 6, except for changes in the formulation of the adhesive and the thickness of the adhesive layer as shown in Tables 3 to 6, urethane-based or acrylic-based adhesive sheets were manufactured in the same manner as in Example 1. The evaluation results are shown in Tables 7 to 10.

[0169] [Example 28] The following materials were mixed and stirred using a disperser to obtain a carbamate adhesive in a single process. Otherwise, a carbamate adhesive sheet was manufactured in the same manner as in Example 1. Compounds containing active hydrogen groups (HX-1): 40 parts; Compounds containing active hydrogen groups (HX-2): 60 parts; Polyfunctional isocyanate compound (I-1): 15 parts; Dibutyltin dilaurate (catalyst): 0.1 parts; Tin 2-ethylhexanoate (catalyst): 0.04 parts; Free radical polymerizable monomer (MH-1): 25 parts; Free radical polymerizable monomer (MO-4): 10 parts; Photopolymerization initiator (RI-1): 1 part; Photopolymerization initiator (RI-2): 1 part; Gas generator (G-18): 20 parts; Antioxidant (O-1): 0.1 parts; Antistatic agent (AS-1): 0.1 parts; Ethyl acetate (solvent): 80 parts. The formulation composition of the adhesive, the thickness of the adhesive layer, and the evaluation results are shown in Tables 5 and 9.

[0170] [Evaluation Items and Evaluation Methods] The evaluation items and methods for adhesive sheets are as follows.

[0171] [Adhesion and re-peelability before ultraviolet (UV) irradiation] Cut test pieces with a width of 25 mm and a length of 100 mm from the obtained adhesive sheet and place them in an atmosphere of 23℃-50%RH for 30 minutes. Then, under the same atmosphere, peel off the release liner from the test piece, attach the exposed adhesive layer side of the test piece to a stainless steel (SUS) plate, press it using a 2 kg roller, and leave it for 24 hours. For the resulting adhered object with the adhesive sheet, according to JIS Z0237, use a tensile testing machine (Tensilon: Orientic Co., Ltd.) at a peel speed of 0.3 m / min and a peel angle of 180° to determine the adhesion (adhesion before UV irradiation). Lower adhesion indicates higher re-peelability and easier re-attachment. The evaluation criteria are as follows. ◎: Below 10gf / 25mm, excellent. ○: Good for values ​​above 10gf / 25mm to below 20gf / 25mm. △: For those exceeding 20gf / 25mm but below 26gf / 25mm, it is acceptable. ×: If the thickness exceeds 26gf / 25mm, it cannot be used practically.

[0172] [The degree to which the material is less prone to peeling due to airflow before ultraviolet (UV) irradiation] Cut test pieces with a width and length of 100 mm from the obtained adhesive sheet and place them in an atmosphere of 23°C and 50% RH for 30 minutes. Then, under the same atmosphere, peel off the release liner from the test piece and attach the exposed adhesive layer of the test piece to an acrylic resin board (Mitsubishi Rayon Corporation's "Acrylite L", 110 mm wide and 110 mm long) that is slightly larger than the test piece, and place it for 24 hours. The bonding is performed with the center of the test piece roughly aligned with the center of the acrylic resin board. For the obtained adhesive sheet, at a position 10mm away horizontally from one end edge of the adhesive sheet, use an air gun with a nozzle diameter of 2.0mmφ to spray air for 10 seconds at a compressed pump pressure of 0.3MPa to check whether the adhesive sheet has peeled off. The above test was performed on 20 test pieces to study the number of test pieces that peeled off (peel count). When no adhesive sheet peeled off for all test pieces (i.e., the peel count was 0), the adhesive sheet was less likely to peel off from the adhered body during the manufacturing process of LCD and touch panel displays, thus demonstrating good performance. ◎: The number of strippings is 0, which is excellent. ×: The number of strippings is 1 to 20, which is not practical.

[0173] [Self-weight adhesion (ease of wetting and spreading) before ultraviolet (UV) irradiation] Cut test pieces with a width of 100 mm and a length of 200 mm from the obtained adhesive sheet and place them in an atmosphere of 23℃-50%RH for 30 minutes. Then, under the same atmosphere, peel off the release sheet from the test piece and evaluate the self-adhesion as follows. Holding the adhesive sheet by both long sides with both hands, bend the adhesive sheet with the adhesive layer facing outwards, bringing the two ends together. In this position, bring the central adhesive layer of the adhesive sheet into contact with an acrylic resin board (Mitsubishi Rayon Corporation's "Acrylite L"). Release both hands from this position. Measure the time from releasing the hands until the entire adhesive layer adheres to the acrylic resin board under its own weight; this is called the self-weight adhesion time, and the wetting and spreading properties of the adhesive are evaluated. The shorter the self-weight adhesion time, the better the wetting and spreading properties (affinity to the adherend). The evaluation criteria are as follows. ◎: Self-weight adhesion time is less than 8 seconds [,]excellent. ○: The self-weight adhesion time is more than 8 seconds but less than 10 seconds, which is good. △: The self-weight adhesion time is more than 10 seconds but less than 15 seconds, which is acceptable. ×: The self-weight adhesion time exceeds 15 seconds, making it unusable.

[0174] Ultraviolet (UV) Penetration Cut test pieces with a width of 20 mm and a length of 40 mm from the obtained adhesive sheet and place them in an atmosphere of 23℃-50%RH for 30 minutes. Then, under the same atmosphere, peel off the release film from the test piece and measure the transmission spectrum using a spectrophotometer (V-750 manufactured by Nippon Spectrophotometer Co., Ltd.). The transmittance (UV transmittance) of the adhesive sheet at a wavelength of 365 nm was measured. The evaluation criteria are as follows. ◎: UV transmittance below 81% [,]excellent. ○: UV transmittance is above 81% to below 82%, which is good. ×: UV transmittance exceeds 82%, making it impractical.

[0175] [Foaming caused by ultraviolet (UV) radiation] Cut test pieces with a width of 25 mm and a length of 100 mm from the obtained adhesive sheet and place them in an atmosphere of 23°C-50%RH for 30 minutes. Then, under the same atmosphere, peel off the release sheet from the test piece, attach the exposed adhesive layer of the test piece to an acrylic resin board ("Acrylite L" manufactured by Mitsubishi Rayon Co., Ltd.), press it with a 2 kg roller, and place it for 24 hours. Subsequently, the test specimen was irradiated with ultraviolet (UV) light from the PET sheet (as substrate) at a cumulative light intensity of 1000 mJ using a high-pressure mercury lamp (peak wavelengths: 254 nm, 365 nm, 405 nm, and 435 nm; output: 120 W). After air cooling for 1 hour in an atmosphere of 23°C and 50% RH, the area of ​​the adhesive sheet closely bonded to the acrylic resin board was measured, and the bonding area ratio was calculated based on the following formula. The evaluation criteria are as follows. [Close contact area ratio (%)] = [Area of ​​the close contact part (cm 2)] / 25 (cm 2). ◎: The ratio of closely spaced areas is below 5%, which is excellent. ○: The ratio of close contact area is between 5% and 20%, which is good. △: The ratio of close contact area is between 20% and 70%, which is acceptable. ×: If the close contact area ratio exceeds 70%, it cannot be used practically.

[0176] [Ease of peeling caused by airflow after ultraviolet (UV) irradiation] Using the same method as the evaluation of "the degree to which it is not easily peeled off by air before ultraviolet (UV) irradiation", test pieces with a width of 100 mm and a length of 100 mm were cut from the obtained adhesive sheet. The release sheet was peeled off, and the exposed adhesive layer was attached to a larger acrylic resin plate and left for 24 hours. Subsequently, using the same method as the evaluation of "foaming property caused by ultraviolet (UV) irradiation", the test piece was irradiated with ultraviolet (UV) irradiation from the PET sheet side used as the substrate, and then air-cooled for 1 hour in an atmosphere of 23°C-50%RH. Using the same method as the evaluation of "the degree to which the adhesive sheet is not easily peeled off by air before ultraviolet (UV) irradiation", air is sprayed onto the adhesive sheet after UV irradiation to confirm whether the adhesive sheet peels off. The above test was performed on 20 specimens to study the number of specimens that peeled off (peel count). Unlike before UV irradiation, after UV irradiation, a higher peel count indicates easier peeling from the adherend, which is good. The optimal result is peeling off of all specimens (i.e., a peel count of 20). Furthermore, the aforementioned peeling process performed by blowing air does not require the steps of holding the end of the adhesive sheet with hands or tools, nor the steps of peeling off the adhesive sheet, and can be regarded as natural peeling or close to the level of natural peeling. ◎: The number of stripping samples is 20, which is excellent. ○: The number of stripping particles is 10 to 19, which is good. △: The number of strippings is 1 to 10, which is acceptable. ×: The number of strippings is 0, making it unusable.

[0177] [Self-weight adhesion after ultraviolet (UV) irradiation (degree of resistance to wetting and spreading)] Cut test pieces with a width of 100 mm and a length of 200 mm from the obtained adhesive sheet and place them in an atmosphere of 23℃-50%RH for 30 minutes. Subsequently, using the same method as the evaluation of "foaming property caused by ultraviolet (UV) irradiation", the test piece was irradiated with ultraviolet (UV) irradiation from the PET sheet side used as the substrate, and then air-cooled for 1 hour in an atmosphere of 23°C-50%RH. Subsequently, the release film was peeled off by the test film under the same atmosphere, and the self-weight adhesion was evaluated as follows. Hold the adhesive sheet by both long sides with both hands, and bend the adhesive sheet with the adhesive layer facing outwards, bringing the two ends of the adhesive sheet together. In this position, bring the adhesive layer in the center of the adhesive sheet into contact with the acrylic resin board ("Acrylite L" manufactured by Mitsubishi Rayon). In this position, release both hands from holding the two ends. After releasing both hands for 30 seconds, measure the area of ​​the adhesive patch that is in close contact with the acrylic resin board, and calculate the contact area ratio based on the following formula. The smaller the contact area ratio, the less likely it is to self-adhere to the acrylic resin board, which is considered good. The evaluation criteria are as follows. [Close contact area ratio (%)] = [Area of ​​the close contact part (cm 2)] / 200 (cm 2). ◎: The close contact area ratio after 30 seconds is 0%, which is excellent. ○: The close contact area ratio after 30 seconds is between 0% and 10%, which is good. △: The ratio of close contact area after 30 seconds is between 10% and 100%, which is acceptable. ×: If the time required for the contact area ratio to reach 100% is less than 30 seconds, or if the contact area ratio reaches 100% after 30 seconds, it is not practical.

[0178] [Table 3]

[0179] [Table 4]

[0180] [Table 5]

[0181] [Table 6]

[0182] [Table 7]

[0183] [Table 8]

[0184] [Table 9]

[0185] [Table 10]

[0186] [Summary of Evaluation Results] The adhesive layers of the adhesive sheets obtained in Examples 1 to 28 all have an adhesion time of less than 15 seconds to the acrylic resin board under its own weight, and good wetting and spreading properties to the adhered body. The adhesive sheets obtained in these embodiments all have moderate adhesion before UV irradiation, have the ability to re-peel off the adhered object, and can be attached with an adhesion that does not easily peel off the adhered object even when blown on. The adhesive sheets obtained in these embodiments all have a UV transmittance of more than 20% to less than 82%, and good UV transmittance and UV absorption. In these embodiments, the adhesive sheets obtained all clearly show the phenomenon of gas generation from the adhesive layer due to UV irradiation, effectively reducing the close contact area ratio of the adhesive sheet to the adhered object. The adhesive sheets obtained in these embodiments were all polymerized by free radical monomers (M) through UV irradiation. The adhesive strength and wettability of the adhesive layer were reduced, and gas was generated from the adhesive layer. As a result, the sheets could be easily peeled off from the adherend by blowing air after UV irradiation. The peelability after UV irradiation was at or close to the level of natural peeling.

[0187] The adhesive sheet of Comparative Example 1, which uses an acrylic adhesive containing a free radical polymerizable monomer (M) and a gas generating agent (G), exhibited very high adhesion but poor re-peelability before UV irradiation. Furthermore, before UV irradiation, its self-weight adhesion time to the acrylic resin board exceeded 15 seconds, and its wetting and spreading properties to the adhered object were poor.

[0188] The adhesive sheet obtained in Comparative Example 2, which uses an urethane-based adhesive that does not contain free radical polymerizable monomers (M) and gas generating agents (G), has moderate adhesion before UV irradiation, has the ability to re-peel off the adhered object, and can be attached with an adhesion that does not easily peel off the adhered object even when blown on. The adhesive sheet system obtained in this comparative example has a UV transmittance of over 82% and poor UV absorption. In addition, during UV irradiation, there is no reduction in the adhesion and wettability of the adhesive layer caused by the polymerization of free radical polymerizable monomers (M), nor is there any gas generation in the self-adhesive layer. Therefore, after UV irradiation, the effects of blow-out peeling and reduced wettability cannot be obtained.

[0189] The adhesive sheet system obtained in Comparative Example 3, which uses an urethane-based adhesive that does not contain free radical polymerizable monomers (M) and contains a small amount of gas generating agent (G), has a UV transmittance of over 82% and poor UV absorption. In this comparative example, during UV irradiation, there was no reduction in the adhesive strength and wettability of the adhesive layer due to the polymerization of the free radical polymerizable monomer (M). Little gas was generated in the self-adhesive layer; therefore, after UV irradiation, the effects of forced-air peeling and reduced wettability could not be achieved. Even with UV irradiation, the wettability remained high; therefore, it can be considered that even if some parts peeled off due to gas generation, they could easily re-adhere, and the peelability was not improved.

[0190] In Comparative Example 4, which used an urethane-based adhesive that did not contain a free radical polymerizable monomer (M) but contained a large amount of a gas-generating agent (G), the adhesive sheet produced a lot of gas in the self-adhesive layer during UV irradiation. However, there was no reduction in the adhesive strength and wettability of the adhesive layer due to the polymerization of the free radical polymerizable monomer (M). Therefore, after UV irradiation, the effects of blown-off peeling and reduced wettability could not be achieved. Even after UV irradiation, the wettability remained high. Therefore, it can be considered that even if there were parts that peeled off due to gas generation, they could easily self-adhere again, and the peelability was not improved.

[0191] The adhesive sheet system obtained in Comparative Example 5, which uses an urethane-based adhesive containing a free radical polymerizable monomer (M) and without a gas-generating agent (G), has a UV transmittance of over 82% and poor UV absorption. In this comparative example, although the adhesion and wettability of the adhesive layer decreased due to the polymerization of the free radical polymerizable monomer (M) during UV irradiation, no gas was generated. Therefore, the effect of blown-out peeling could not be obtained after UV irradiation.

[0192] The adhesive sheet system obtained in Comparative Example 6, which uses an urethane-based adhesive that does not contain a gas-generating agent (G) and has a reduced amount of free radical polymerizable monomer (M) compared to Comparative Example 5, exhibits a UV transmittance exceeding 82% and poor UV absorption. Furthermore, during UV irradiation, there is almost no reduction in the adhesive strength and wettability of the adhesive layer due to the polymerization of the free radical polymerizable monomer (M), nor is there any gas generation in the self-adhesive layer. Therefore, after UV irradiation, the effects of blown-out peeling and reduced wettability cannot be achieved.

[0193] This invention is not limited to the above-described embodiments and examples. As long as it does not deviate from the spirit of this invention, appropriate design changes can be made.

[0194] 10,20: Adhesive sheet 11,21: Substrate sheet 12, 22A, 22B: Adhesive layer 13, 23A, 23B: Peeling sheets

Claims

1. An adhesive sheet comprising: a substrate sheet, and an adhesive layer formed on the substrate sheet and having the properties of curing with an active energy line; wherein the adhesive layer is a coated and dried product containing an adhesive comprising: one or more non-radical polymerizable polyols having multiple hydroxyl groups and not having (meth)acrylic groups; one or more radical polymerizable monomers (M), including one or more radical polymerizable monomers containing active hydrogen groups (MH), wherein the one or more radical polymerizable monomers containing active hydrogen groups (MH) have one or more active hydrogen groups and two or more (meth)acrylic groups; a polyfunctional isocyanate compound (I); and a gas generator (G) that generates nitrogen gas by irradiation with an active energy line; wherein the adhesive layer, according to Japanese Industrial Standard JIS Z0237, has an adhesion strength of 0.1 gf / 25 mm to 26 gf / 25 mm as measured using a tensile testing machine under conditions of a peel speed of 0.3 m / min and a peel angle of 180°.

2. The adhesive sheet described in claim 1 has a transmittance of 1% to 82% at a wavelength of 365 nm.

3. The adhesive sheet as described in claim 1 or 2, wherein the content of the gas generating agent (G) in the aforementioned adhesive layer is 2% by mass or more.

4. The adhesive sheet as described in claim 1 or 2, wherein the aforementioned gas generator is a nitrogen-containing compound containing N=N bonds and generating nitrogen gas by irradiation of an active energy line.

5. The adhesive sheet as described in claim 4, wherein the aforementioned gas generating agent is at least one selected from the group consisting of azo compounds, azido compounds, tetrazolium compounds, tetrazolium compound salts, and bis-tetrazole compounds.

6. The adhesive sheet as described in claim 4, wherein the volume of N2 generated per 1g of the aforementioned gas generating agent, calculated theoretically according to the chemical formula, is from 30mL / g to 400mL / g.

7. The adhesive sheet as described in claim 1 or 2, wherein one or more monomers containing active hydrogen groups (MH) comprises one or more monomers containing active hydrogen groups with five or more functions (MHF), wherein the aforementioned monomers containing active hydrogen groups with five or more functions (MHF) have one or more active hydrogen groups and five or more (meth)acrylic acid groups.

8. The adhesive sheet as described in claim 1 or 2, wherein one or more free radical polymerizable monomers (M) comprises one or more monomers (MHF) with five or more functional groups containing active hydrogen groups, wherein the aforementioned one or more monomers (MHF) with five or more functional groups containing active hydrogen groups have one or more active hydrogen groups and five or more (meth)acrylic acid groups; the total amount of the one or more free radical polymerizable monomers (M) is 70% to 100% by mass relative to the total amount of the free radical polymerizable monomers (M).

9. The adhesive sheet as described in claim 1 or 2, wherein the aforementioned non-radical polymerizable polyol is a reaction product of one or more active hydrogen-containing compounds (HX) having multiple active hydrogen groups and one or more polyisocyanates (N), and is a hydroxyl-terminated aminocarbamate prepolymer (UPH) without (meth)acrylic acid groups.

10. The adhesive sheet as described in claim 9, wherein one or more of the compounds (HX) containing active hydrogen groups comprise a trifunctional or higher polyol having three or more hydroxyl groups.

11. The adhesive sheet as described in claim 9, wherein the amount of free radical polymerizable monomer (M) is from 10 to 150 parts by mass relative to 100 parts by mass of hydroxyl-terminated aminocarbamate prepolymer (UPH).

12. The adhesive sheet as described in claim 9, wherein the amount of the polyfunctional isocyanate compound (I) is from 5 to 35 parts by mass relative to 100 parts by mass of the hydroxyl-terminated carbamate prepolymer (UPH).

13. The adhesive sheet described in claim 1 or 2, wherein the self-weight adhesion time of the aforementioned adhesive layer to the acrylic resin board, as determined by the following method, is 15 seconds or less; Method for determining the self-weight adhesion time: Hold the two ends of the aforementioned adhesive sheet with a width of 100 mm and a length of 200 mm with both hands, bend the aforementioned adhesive sheet with the aforementioned adhesive layer facing outwards, and bring the aforementioned two ends of the aforementioned adhesive sheet together; in this state, bring the aforementioned adhesive layer of the central portion of the aforementioned adhesive sheet into contact with the aforementioned acrylic resin board; in this state, release both hands holding the aforementioned two ends; measure the time from when both hands are released until the aforementioned adhesive layer is completely in contact with the aforementioned acrylic resin board as the self-weight adhesion time.

14. The adhesive sheet described in claim 1 or 2 is used as a surface protectant.

15. An adhesive body having an adhesive sheet, wherein the adhesive sheet as described in any one of claims 1 to 14 is attached to the adhesive body.

16. A method of using an adhesive sheet, comprising using an adhesive sheet as described in any one of claims 1 to 14, and comprising the steps of: attaching the adhesive sheet to the surface of an object to be adhered; and irradiating the adhesive sheet attached to the surface of the object with an active energy line to reduce the adhesive force of the adhesive sheet.

17. A method of using an adhesive sheet, comprising using an adhesive sheet as described in any one of claims 1 to 14, and including the following steps: attaching the adhesive sheet to the surface of an adhesive body; and irradiating the adhesive sheet attached to the surface of the adhesive body with an active energy line to reduce the adhesive force of the adhesive sheet, such that the self-weight adhesion time of the adhesive layer to the acrylic resin board after irradiation, as measured by the following method, is 30 seconds or more, thereby reducing the adhesive force and peeling the adhesive sheet off from the adhesive body; the method for measuring the self-weight adhesion time is as follows: Hold the two ends of the aforementioned adhesive sheet, which is 100mm wide and 200mm long, with both hands. Bend the adhesive sheet with the adhesive layer facing outwards and bring the two ends of the adhesive sheet together. In this state, bring the adhesive layer of the central part of the adhesive sheet into contact with the acrylic resin board. In this state, release the hands holding the two ends. Measure the time from when the hands are released until the adhesive layer is completely adhered to the acrylic resin board as the self-weight adhesion time.

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