JP5836535B2 - Adhesive composition and easily dismantling adhesive tape - Google Patents

Description

  The present invention provides an easily dismantleable adhesive tape that can be easily disassembled after a certain period of time after being attached to an adherend and fixing between articles, and an adhesive composition that provides the easily dismantleable adhesive tape Related to things.

  Adhesive tape is a bonding means with excellent workability and high bonding reliability. It is used to fix parts in various industrial fields such as OA equipment, IT / home appliances, automobiles, temporarily fix parts, and label to display product information. Used for applications. In recent years, from the viewpoint of protecting the global environment, there is an increasing demand for recycling and reuse of used products in various industrial fields such as home appliances and automobiles. When recycling and reusing various products, it is necessary to fix the parts and peel off the adhesive tape used for the labels. However, since the adhesive tape is provided at various locations in the product, Reduction of the work cost by a removal process is desired.

  As an easily disassembleable pressure-sensitive adhesive tape, for example, a pressure-sensitive adhesive member having two or more pressure-sensitive adhesive layers having different adhesive forces is disclosed (see Patent Document 1). The adhesive tape is obtained by bonding the adherend through a weak adhesive layer in an adhesive member having an adhesive layer having a superposed structure, so that the adherend is firmly fixed and the weak adhesive layer can be easily used as a release surface. It is an adhesive member that realizes easy disassembly. However, since the adhesive member has a plurality of adhesive layers as essential components, there is a problem that the manufacturing cost is increased. Moreover, since it is the structure by which adhesion | attachment with a to-be-adhered body is performed by a weak adhesion layer, there exists a restriction | limiting in improving adhesive force, and the expansion | deployment to the use which fixes an article | item firmly was difficult.

  As another easily disassembleable pressure-sensitive adhesive tape, for example, a foamable adhesive composition having a foamable component having a t-butyloxycarbonyl structure is disclosed as a pressure-sensitive adhesive composition that foams by light irradiation (patent). Reference 2). Since the pressure-sensitive adhesive tape using the pressure-sensitive adhesive composition is foamed by light irradiation, it can be peeled off from the adherend by light irradiation after application. However, since the pressure-sensitive adhesive composition requires light irradiation, a light irradiation device is required for disassembly, which increases capital investment, and a certain amount of light irradiation is applied to the part where the pressure-sensitive adhesive tape is attached. Therefore, it was difficult to dismantle a large amount at once.

Japanese Patent Laid-Open No. 10-140093 JP 2004-43732 A

  The problem to be solved by the present invention is that an easily dismantleable adhesive tape that can be attached to an adherend and fixed between parts and can be easily disassembled during disassembly and the easily dismantleable adhesive tape can be realized. It is in providing an adhesive composition.

The present invention includes the following aspects.
(1) An acrylic copolymer containing 20 to 90 mol% of (meth) acrylate obtained by reacting (meth) acrylic acid and vinyl ether in the monomer component ,
The acrylic copolymer contains (meth) acrylate having 1 to 14 carbon atoms and a hydroxyl group-containing monomer as monomer components,
Content of the said hydroxyl-containing monomer is 10 mol% or more in the monomer component which comprises the said acrylic copolymer, The adhesive composition characterized by the above-mentioned .
( 2 ) The pressure-sensitive adhesive composition according to ( 1) , wherein the (meth) acrylate having an alkyl group having 1 to 14 carbon atoms is n-butyl acrylate or 2-ethylhexyl acrylate.
( 3 ) The (1) or (1) above, wherein the content of (meth) acrylate obtained by reacting the (meth) acrylic acid and vinyl ether is 60 to 90 mol% in the monomer component constituting the acrylic copolymer. The pressure-sensitive adhesive composition according to (2) .
( 4 ) An easily disassembleable pressure-sensitive adhesive tape comprising a pressure-sensitive adhesive layer comprising the pressure-sensitive adhesive composition according to any one of (1) to ( 3 ).

  According to the pressure-sensitive adhesive composition of the present invention, it can be attached to an adherend, and can be easily disassembled by being immersed in warm water during disassembly. Moreover, adhesive performance etc. are easily controllable by copolymerizing monomers, such as a (meth) acrylate monomer and a hydroxyl-containing monomer, as a copolymerizable monomer. Therefore, it is suitable for OA equipment, IT / household appliances, automobiles, etc. used for recycling and reuse, for parts fixing, parts temporarily fixing, labels for displaying product information, etc. And can be easily disassembled by immersion in warm water during disassembly. Moreover, since it can be easily disassembled with hot water, expensive dismantling facilities and lines are not required, and a large amount of dismantling can be performed efficiently, and dismantling work can be realized easily and at low cost.

[Acrylic copolymer]
In the pressure-sensitive adhesive composition of the present invention, an acrylic copolymer containing 20 to 90 mol% of (meth) acrylate obtained by reacting (meth) acrylic acid and vinyl ether is used. By using (meth) acrylate obtained by reacting the (meth) acrylic acid and vinyl ether as a monomer component constituting the acrylic copolymer, it can be attached to an adherend, and warm water is used at the time of disassembly. It is possible to realize an adhesive tape that can be easily disassembled by dipping in the water.

  Examples of the (meth) acrylate obtained by reacting (meth) acrylic acid and vinyl ether include 1-ethoxyethyl (meth) acrylate, 1-propyloxyethyl (meth) acrylate, and 1-isopropyloxyethyl (meth). Acrylate, 1-butoxyethyl (meth) acrylate, 1-isobutoxyethyl (meth) acrylate, t-butoxyethyl (meth) acrylate, 1- (2-hydroxyethoxy) ethyl (meth) acrylate, 1- (4-hydroxy Butoxy) ethyl (meth) acrylate, 1-cyclohexyloxyethyl (meth) acrylate, 1- (2-ethylhexyloxy) ethyl (meth) acrylate, 1- (2-chloroethoxy) ethyl (meth) acrylate, 1-dodecyloxy Ethyl (meta Acrylate, 1-octadecyloxyethyl (meth) acrylate, 1- (2,2,2-trifluoroethoxy) ethyl (meth) acrylate, 1- (tris (trimethylsilyl) silyloxy) ethyl (meth) acrylate, 1-hexadecyl Oxyethyl (meth) acrylate, 1-isooctyloxyethyl (meth) acrylate, 1- (decylcarbonyloxy) ethyl (meth) acrylate, 1- (2- (2-hydroxyethoxy) ethoxy) ethyl (meth) acrylate, etc. 1-alkoxyethyl (meth) acrylate, 2- (4-methyl) tetrahydropyranyl (meth) acrylate, 2- (6-methyl) tetrahydropyranyl (meth) acrylate, 2- (4-amino) tetrahydropyranyl (Meth) acrylate, 2 (6-hydroxymethyl) tetrahydropyranyl (meth) acrylate, 2- (5-chlorotetrahydropyranyl) (meth) acrylate, 2- (6-aminomethyl) tetrahydropyranyl (meth) acrylate, 2- (6- Methoxy) tetrahydropyranyl (meth) acrylate, 2- (6-ethoxy) tetrahydropyranyl (meth) acrylate, 2- (6-t-butoxy) tetrahydropyranyl (meth) acrylate, 2- (6- (2- Aminoethyl)) tetrahydropyranyl (meth) acrylate, 2- (6-phenyl) tetrahydropyranyl (meth) acrylate, 2- (6,6-dihydroxymethyl) tetrahydropyranyl (meth) acrylate, 2- (4 6-dimethyl) tetrahydropyranyl (meth) acrylate, etc. Tetrahydrofuranyl (meth) acrylate such as lahydropyranyl (meth) acrylate, 2-tetrahydrofuranyl (meth) acrylate, 2- (4-t-butyl) tetrahydrofuranyl (meth) acrylate, 2- (4-isopropyl) tetrahydrofuranyl (meth) acrylate, etc. ) Acrylate, 2-tetrahydrooxepanyl (meth) acrylate, and (meth) acrylates such as tetrahydrooxepanyl (meth) acrylate such as 2- (7-phenyl) tetrahydrooxepanyl (meth) acrylate can be preferably used. These (meth) acrylates may be used alone or in combination of two or more. Among these (meth) acrylates, 1-alkoxyethyl (meth) acrylate and tetrahydropyranyl (meth) acrylate can be particularly preferably used.

  The amount of (meth) acrylate obtained by reacting (meth) acrylic acid and vinyl ether is 20 to 90 mol% in the monomer component constituting the acrylic copolymer, so that it is attached to the adherend. It is possible to realize an adhesive tape that can be easily disassembled by immersion in warm water during disassembly. The amount of the monomer used is preferably 30 to 90 mol%, and more preferably 40 to 80 mol%, because particularly suitable adhesiveness is easily obtained. Further, by setting the content of the (meth) acrylate to 60 mol% or more in the monomer component constituting the acrylic copolymer, it is difficult for adhesive residue on the peeled surface to occur during disassembly by hot water immersion, and the adhesive layer / It becomes easy to obtain suitable interfacial peelability at the adherend interface and the adhesive layer / substrate interface.

  In the acrylic copolymer used in the present invention, as a copolymerizable monomer to be copolymerized with (meth) acrylate obtained by reacting (meth) acrylic acid and vinyl ether, an adhesive is used depending on the application to be used. Various monomers used in the acrylic copolymer can be appropriately used. Examples of the copolymerizable monomer include (meth) acrylate having an alkyl group having 1 to 14 carbon atoms, a hydroxyl group-containing vinyl monomer, a carboxyl group-containing vinyl monomer, an amino group-containing vinyl monomer, an imino group-containing vinyl monomer, and an amide. Examples thereof include a group-containing vinyl monomer. These copolymerizable monomers may be used alone or in combination.

  Among these, it is preferable to use at least one of a (meth) acrylate having a C 1-14 alkyl group and a hydroxyl group-containing vinyl monomer because suitable adhesive performance is easily obtained.

  Examples of the (meth) acrylate having an alkyl group having 1 to 14 carbon atoms include methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, n-nonyl (meth) acrylate, isononyl (meth) acrylate, n-decyl (meth) acrylate, isodecyl (meth) acrylate, n-undecyl (meth) acrylate, n-dodecyl (meth) acrylate, n-tridecyl (meth) acrylate, and / or n-tetradecyl (meth) acrylate, and the like can be used. Especially, since n-butyl (meth) acrylate and / or 2-ethylhexyl (meth) acrylate are suitable for the adhesive improvement of the adhesive layer obtained, it is preferable.

  In the case of using a (meth) acrylate monomer having 1 to 14 carbon atoms, it is preferable because it becomes easy to realize suitable adhesiveness by being 5 mol% or more in all monomer components constituting the acrylic copolymer, More preferably, it is 10-70 mol%, It is further more preferable that it is 10-50 mol%, It is especially preferable that it is 10-40 mol%.

  Examples of the hydroxyl group-containing vinyl monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 4-hydroxybutyl ( (Meth) acrylate, 2-hydroxyhexyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate, etc. It can be appropriately selected and used. Especially, since 2-hydroxyethyl (meth) acrylate or 4-hydroxybutyl (meth) acrylate is suitable for the adhesive improvement of the adhesive layer obtained, it can be preferably used, and especially 2-hydroxyethyl (meth) acrylate is used. It can be preferably used.

  In the case of using a hydroxyl group-containing vinyl monomer, it is preferable to set it to 1 mol% or more in all monomer components constituting the acrylic copolymer, so that preferable adhesiveness is easily realized, and is preferably 3 to 30 mol%. Is more preferable, and it is further more preferable that it is 3-20 mol%. In addition, by setting the content of the hydroxyl group-containing vinyl monomer to 10 mol% or more of the total monomer components, adhesive residue on the peeled surface hardly occurs at the time of disassembly by hot water immersion, and the pressure-sensitive adhesive layer / adherent interface or pressure-sensitive adhesive layer / It becomes easy to obtain suitable interface peelability at the substrate interface.

  In addition, as the carboxyl group-containing vinyl monomer, for example, a monomer having a carboxyl group such as acrylic acid, methacrylic acid, itaconic acid, maleic acid, crotonic acid, acrylic acid dimer, ethylene oxide-modified succinic acid acrylate, or the like may be used. it can.

  Examples of amide group-containing vinyl monomers include acrylamide, methacrylamide, diethylacrylamide, N-vinylpyrrolidone, N, N-dimethylacrylamide, N, N-dimethylmethacrylamide, N, N-diethylacrylamide, N, N. -Diethyl methacrylamide, N, N'-methylenebisacrylamide, N, N-dimethylaminopropyl acrylamide, N, N-dimethylaminopropyl methacrylamide, diacetone acrylamide, etc. can be used. Examples of amino group-containing vinyl monomers include Aminoethyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate, and the like can be used.

  As the imino group-containing monomer, for example, cyclohexylmaleimide, isopropylmaleimide, N-cyclohexylmaleimide, itaconimide and the like can be used.

  When a carboxyl group-containing vinyl monomer, an amide group-containing vinyl monomer, an amino group-containing vinyl monomer, and an imino group-containing vinyl monomer are used, the total amount of these monomers in the monomer component constituting the acrylic polymer It is preferably 30 mol% or less, more preferably 25 mol% or less, and further preferably 1 to 20 mol%.

  What is necessary is just to adjust suitably the weight average molecular weight of the acryl-type copolymer used for this invention in the range of about 10,000-2 million according to a use aspect. Since it is easy to ensure good adhesive strength before dismantling, it is preferably about 50,000 to 1,500,000, particularly preferably about 100,000 to 1,000,000.

  The weight average molecular weight and the number average molecular weight are in terms of standard polystyrene by gel permeation chromatography (GPC). As an example of measurement conditions, HLC-8220GPC (manufactured by Tosoh Corporation) is used, the column is TSKgel GMHXL (manufactured by Tosoh Corporation), the column temperature is 40 ° C., the eluent is tetrahydrofuran, the flow rate is 1.0 mL / min, and standard polystyrene. Can be measured by using TSK standard polystyrene.

  In order to adjust the molecular weight, a chain transfer agent may be used in the polymerization. Examples of the chain transfer agent include known chain transfer agents such as lauryl mercaptan, glycidyl mercaptan, mercaptoacetic acid, 2-mercaptoethanol, thioglycolic acid, 2-ethylhexyl thioglycolate, and 2,3-dimethylcapto-1-propanol. Can be used.

  The acrylic copolymer used in the present invention may be in the form of a random copolymer or a block copolymer having a 1-butoxyethyl acetate block. In the case of a random copolymer, it is preferable because the production becomes simple, and in the case of a block copolymer, it is preferable because a suitable dismantling property is easily obtained.

  The acrylic polymer can be produced, for example, by subjecting a mixture of the acrylic monomers to a radical polymerization reaction. Specific examples of the method for producing the acrylic polymer include a living radical polymerization method and a conventionally known radical polymerization method using an azo initiator or a peroxide. In particular, the adoption of the living radical polymerization method does not cause side reactions such as chain transfer reaction and termination reaction in the radical polymerization process, and it can suppress the formation of low molecular weight components and produce an acrylic polymer with a narrow molecular weight distribution. This is preferable because it is possible.

  Examples of the living radical polymerization method include an atom transfer radical polymerization method (ATRP method), a living radical polymerization method using an organic hetero compound containing a high-frequency group 15 or group 16 element as a catalyst (radical weight mediated by an organic hetero compound). (Combined method) (TERP method, etc.), living radical polymerization method (NMP method) via nitroxide, reversible addition-fragmentation chain transfer polymerization method (RAFT method), and the like.

  The atom transfer radical polymerization method (ATRP method) is a method of polymerizing the above acrylic monomer in the presence of, for example, a transition metal complex and an organic halide.

  As the transition metal constituting the transition metal complex, for example, Cu, Ru, Fe, Rh, V, Ni, and halides thereof can be used. Examples of the ligand that coordinates to the transition metal include bipyridyl derivatives, mercaptan derivatives, trifluorate derivatives, tertiary alkylamine derivatives, and the like.

  The organic halide is a polymerization initiator, for example, methyl 2-bromo (or chloro) propionate, ethyl 2-bromo (or chloro) propionate, methyl 2-bromo (or chloro) -2-methylpropionate 2-bromo (or chloro) -2-methylpropionic acid, 1-phenylethyl chloride (or bromide), 2-hydroxyethyl 2-bromo (or chloro) propionate, 2-bromo (or chloro) propionic acid 4 -Hydroxybutyl, 2-hydroxyethyl 2-bromo (or chloro) -2-methylpropionate, 4-hydroxybutyl 2-bromo (or chloro) -2-methylpropionate, and the like can be used.

  The radical polymerization method mediated by an organic hetero compound is a method of polymerizing the above-mentioned acrylic monomer in the presence of an organic hetero compound and a radical initiator. The radical polymerization method mediated by the organic hetero compound is preferable because the molecular weight of the acrylic copolymer is easily increased and the adhesive force is easily improved.

  As the organic hetero compound used in the radical polymerization method mediated by the organic hetero compound, an organic tellurium compound, an organic ditelluride compound, an organic bismuth compound, and an organic antimony compound can be preferably used. Specific examples of these organic hetero compounds include JP-A No. 2004-323893, WO 2004/14818, JP-A 2006-225524, JP-A 2006-299278, JP-A 2008-291216, JP-A 2009. Organic tellurium compounds, organic ditelluride compounds disclosed in JP-A-1149877, etc., organic bismuth compounds disclosed in JP2009-149877A, WO2006 / 62255, etc., JP2009-149877A, WO2006 / 1496 Well-known compounds such as organic antimony compounds disclosed in the above can be used as appropriate. Specifically, for example, methyl 2-methylterranyl-2-methylpropionate, ethyl 2-methylterranyl-2-methylpropionate, ethyl 2-n-butyl-2-phenylterranylpropionate, 2-methyl-2- Ethyl phenylterranylpropionate, 2-methylterranylpropionitrile, 2-methyl-2-methylterranylpropionitrile, (methylterranyl-methyl) benzene, (1-methylterranyl-ethyl) benzene, (2-methylterranyl- Propyl) benzene, (1-phenylterranyl-ethyl) benzene, 2-methyl-2-n-butylterranyl-propionic acid ethyl, 2-methyl-2-dimethylbismutanylpropionic acid methyl ester, 2-methyl-2- Diphenylbismutanylpropionitrile, 2-methyl-2-di Tylphenylbismutanylpropionitrile, methyl 2-methyl-2-dimethylstivanylpropionate, 2-methyl-2-dimethylstivanylpropionitrile, 1-dimethylstivanyl-1-phenylethane, dimethylditelluride Diethyl ditelluride, di-n-propyl ditelluride, diisopropyl ditelluride, dicyclopropyl ditelluride, di-n-butyl ditelluride, di-sec-butyl ditelluride, di-tert-butyl ditelluride, dicyclobutyl ditelluride Lido, diphenylditelluride, bis- (p-methoxyphenyl) ditelluride, bis- (p-aminophenyl) ditelluride, bis- (p-nitrophenyl) ditelluride, bis- (p-cyanophenyl) ditelluride, bis- ( p-sulfonylphenyl) ditelluride, dinaphthy Ditelluride, dipyridyl ditelluride, and the like. Preferably, compounds such as dimethyl ditelluride, diethyl ditelluride, di-n-propyl ditelluride, di-n-butyl ditelluride, diphenyl ditelluride and the like can be preferably exemplified.

[Adhesive composition]
By containing the acrylic copolymer, the pressure-sensitive adhesive composition of the present invention can realize good adhesive performance, and can realize a pressure-sensitive adhesive layer that can be suitably disassembled by immersion in warm water.

  The pressure-sensitive adhesive composition of the present invention is a pressure-sensitive adhesive composition containing the acrylic copolymer as a main component in the pressure-sensitive adhesive composition, preferably 50 mol% or more, more preferably 60 mol% or more. Even if it is an adhesive composition containing only said acrylic copolymer as a polymer, it may be an adhesive composition which further contains another acrylic copolymer etc. Moreover, you may contain tackifying resin, a crosslinking agent, another additive, etc. as needed.

(Tackifying resin)
In the pressure-sensitive adhesive composition of the present invention, a tackifying resin may be used in order to adjust the strong adhesion of the pressure-sensitive adhesive layer obtained. Examples of the tackifying resin used in the present invention include rosin, polymerized rosin, polymerized rosin ester, rosin phenol, stabilized rosin ester, disproportionated rosin ester, terpene, terpene phenol, petroleum A resin system etc. can be illustrated.

(solvent)
In the pressure-sensitive adhesive composition of the present invention, a solvent usually used for the pressure-sensitive adhesive composition can be used, and for example, toluene, xylene, ethyl acetate, butyl acetate, acetone, methyl ethyl ketone, hexane and the like can be used. Moreover, when setting it as an aqueous adhesive composition, water or the aqueous solvent which has water as a main can be used.

(Crosslinking agent)
In the pressure-sensitive adhesive composition of the present invention, it is also preferable to use a crosslinking agent for the purpose of improving the cohesive strength of the pressure-sensitive adhesive layer obtained. Examples of the crosslinking agent include known isocyanate crosslinking agents, epoxy crosslinking agents, aziridine crosslinking agents, polyvalent metal salt crosslinking agents, metal chelate crosslinking agents, keto-hydrazide crosslinking agents, oxazoline crosslinking agents, and carbodiimide crosslinking agents. A crosslinking agent, a silane crosslinking agent, a glycidyl (alkoxy) epoxysilane crosslinking agent, or the like can be used.

(Additive)
In the pressure-sensitive adhesive composition of the present invention, as an additive, a base (such as aqueous ammonia), an acid, a foaming agent, and a plasticizer for adjusting pH within a range that does not impair the desired effect of the present invention as necessary. , Softeners, antioxidants, fillers such as glass and plastic fibers, balloons, beads, metal powders, colorants such as pigments and dyes, pH adjusters, film formation aids, leveling agents, thickeners, Known materials such as water repellents and antifoaming agents can be optionally added to the pressure-sensitive adhesive composition. Moreover, you may add an acid catalyst and an acid generator.

  The foaming agent can be used for proceeding with the disassembly of the pressure-sensitive adhesive. For example, an inorganic foaming agent, an organic foaming agent, a thermally expandable hollow sphere, and the like that expand by volume when heated can be used.

  In addition, in the pressure-sensitive adhesive composition of the present invention, by containing an acid catalyst or an acid generator, disassembly by external stimulation of light or heat can be imparted in addition to warm water disassembly. Examples of the acid catalyst include aromatic acids such as p-toluenesulfonic acid and benzenesulfonic acid, organic acids such as aliphatic sulfonic acid, and inorganic acids such as hydrochloric acid and sulfuric acid. As the acid generator, various thermal acid generators and photoacid generators can be used. As the thermal acid generator, for example, sulfonium salt, benzothiazonium salt, ammonium salt, phosphonium salt can be used as the thermal acid generator, and for example, 4-acetoxyphenyldimethyl is used as the photoacid generator. Sulfonium hexafluoroarsenate, benzyl-4-hydroxyphenylmethylsulfonium hexafluoroantimonate, 4-acetoxyphenylbenzylmethylsulfonium hexafluoroantimonate, dibenzyl-4-hydroxyphenylsulfonium hexafluoroantimonate, 4-acetoxyphenylbenzylsulfonium hexa It can be appropriately selected from fluoroantimonate, 3-benzylbenzothiazolium hexafluoroantimonate, and the like. For example, N-hydroxynaphthalimide trifluoromethanesulfonate, N-hydroxynaphthalimide methanesulfonate, N-hydroxynaphthalimide benzenesulfonate, N-hydroxynaphthalimide triflate, bis (cyclohexylsulfonyl) diazomethane, bis (tert- Butylsulfonyl) diazomethane, bis (p-toluenesulfonyl) diazomethane, triphenylsulfonium trifluoromethanesulfonate, diphenyl-4-methylphenylsulfonium trifluoromethanesulfonate, diphenyl-2,4,6-trimethylphenylsulfonium-p-toluenesulfonate, bis (Dodecylphenyl) iodonium hexafluoroantimonate, bis (tert-butylphenol) Nyl) iodonium hexafluorophosphate, bis (tert-butylphenyl) iodonium trifluoromethanesulfonate, triphenylsulfonium trifluoromethanesulfonate, biphenyliodonium trifluoromethanesulfonate, phenyl- (3-hydroxy-pentadecylphenyl) iodonium hexafluoroantimonate, and Phenyl- (3-hydroxypentadecylphenyl) iodonium can be appropriately selected from hexafluoroantimonate and the like.

  Among them, the photoacid generator can suitably disassemble the adhesive layer by two external stimuli of light and heat, while storing it as an adhesive composition or when fixing an article as an adhesive tape. It can be used particularly preferably because it is not easily decomposed or disassembled and can maintain stable storage and adhesive properties. In particular, acid generators such as N-hydroxynaphthalimide trifluoromethanesulfonate ester and bis (cyclohexylsulfonyl) diazomethane alone having a thermal decomposition temperature of about 150 ° C. or more have good stability, such as bis (cyclohexylsulfonyl) diazomethane. The photoacid generator that generates a gas upon heating is a photoacid generator that is particularly easy to realize high dismantling properties and that does not easily generate a gas even when heated to about 100 ° C., such as N-hydroxynaphthalimide trifluoromethanesulfonic acid ester. Is easy to obtain a heat-stable pressure-sensitive adhesive layer, and a photoacid generator having a light-absorbing structure such as a benzene ring or naphthalene ring structure in the skeleton is suitable for a short light irradiation time and a small content. Each can be preferably used because it can realize a good dismantling property.

[Easy disassembly adhesive tape]
The easily disassembleable pressure-sensitive adhesive tape of the present invention is a pressure-sensitive adhesive tape having a pressure-sensitive adhesive layer made of the above pressure-sensitive adhesive composition. The pressure-sensitive adhesive layer may be a single-layer pressure-sensitive adhesive layer or may be a laminate of a plurality of pressure-sensitive adhesive layers. Moreover, even if it is an adhesive tape which has a base material, the form of the adhesive tape which consists only of an adhesive layer which does not have a base material may be sufficient. Moreover, even if it is a form which has an adhesive layer only on the single side | surface of a base material, the form of the double-sided adhesive tape which has an adhesive layer on both surfaces of a base material may be sufficient. In two or more member fixing applications, a pressure-sensitive adhesive tape or a double-sided pressure-sensitive adhesive tape consisting only of a pressure-sensitive adhesive layer can be suitably used.

Examples of the base material include plastics made of polyolefin (eg, polypropylene, polyethylene), polyester (eg, polyethylene terephthalate, polyethylene naphthalate), polystyrene, ABS, polycarbonate, polyimide film, polyvinyl chloride, nylon, polyvinyl alcohol, and the like. Non-woven fabrics made of film, pulp, rayon, Manila hemp, acrylonitrile, nylon, polyester, etc., paper, cloth, metal foil, etc. can be used, and it is easy to achieve both removability and adhesiveness. Can be suitably used.
Further, for the purpose of improving the adhesion between the substrate and the pressure-sensitive adhesive layer, corona treatment, plasma treatment, anchor coating treatment, or the like may be performed on one or both surfaces of the substrate.

  When the easily disintegratable pressure-sensitive adhesive tape of the present invention has a base material, the pressure-sensitive adhesive composition is directly applied to the base material using a roll coater, a die coater, or the like, and then a separator is pasted through a drying step. It can be produced by a direct coating method or a transfer method in which a pressure-sensitive adhesive composition is once coated on a separator and dried, and then transferred to a substrate. When it does not have a base material, it can manufacture by the method of coating an adhesive composition on a separator and bonding another separator.

  The easily disassembleable pressure-sensitive adhesive tape of the present invention is formed by applying and drying the above easily disassembleable adhesive composition on a PET film having a thickness of 50 μm using an applicator having a gap of 8 milli-inch. In a 23 ° C. and 50% RH environment, a hand roller having a weight of 2 kg was reciprocated once on a SUS plate, left to stand for 1 hour, and then left at 180 ° at a speed of 30 mm / min using a tensile tester. The adhesive strength when peeled in the direction is preferably 1 N / 20 mm or more, more preferably 2 to 30 N / 20 mm, and particularly preferably 3 to 20 N / 20 mm. The easily disassembleable pressure-sensitive adhesive tape of the present invention can realize suitable dismantling properties even with high adhesive force suitable for fixing between parts.

(Dismantling method)
The easily disassembleable pressure-sensitive adhesive tape of the present invention is favorably adhered to an object to be adhered and fixed between parts at the time of application, and when disassembling and peeling off, it can be peeled off satisfactorily by immersion in warm water. The condition of the hot water may be appropriately adjusted at a temperature that can achieve good dismantling properties, but is preferably 60 ° C. or higher, and more preferably 80 ° C. or higher.

  The easily disassembleable pressure-sensitive adhesive tape of the present invention can be easily disassembled by immersion in warm water when separating between members during reuse or recycling. For this reason, it can be suitably used as an adhesive tape for fixing parts between various products in industrial applications such as automobiles, building materials, OA, and home appliance industries. In particular, the work efficiency is good when separating a large amount of parts during reuse or recycling, or when separating a large amount of labels.

(Production Example 1) (Synthesis of acrylic copolymer (1))
2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile) (AMVN) 0.83 mg, 1-isobutoxyethyl acrylate (iBEA) 2.04 g, 2-ethylhexyl acrylate (2EHA) 0.25 g, A mixed solution of 0.21 g of 2-hydroxyethyl acrylate (HEA) and 2.50 g of ethyl acetate was put into a test tube and degassed by argon gas bubbling for 30 minutes. 3.14 μL of organic monotellurium compound is added to a test tube using a microsyringe and reacted for 5 hours in an oil bath at 50 ° C. to obtain a reaction solution of an acrylic copolymer (1) which is a random copolymer. It was. ^{From 1} H-NMR (300 MHz) analysis, the polymerization rate of 1-isobutoxyethyl acrylate was 76%, the polymerization rate of 2-ethylhexyl acrylate was 77%, and the polymerization rate of 2-hydroxyethyl acrylate was 81%.

  After completion of the reaction, the polymerization solution was diluted with 20 mL of ethyl acetate, poured into methanol: water (80:20 volume fraction) to precipitate the polymer, and the supernatant was removed by decantation. The resulting precipitate was dissolved in 50 mL of chloroform and poured into methanol: water (80:20 volume fraction) to reprecipitate the polymer. After removing the supernatant liquid by decantation, it was vacuum-dried at 40 ° C. for 10 hours under reduced pressure to obtain an acrylic copolymer (1) as a random copolymer. From the GPC analysis, it was Mn = 99,500, Mw = 143,300, PD = 1.44. The mass ratio of the constituent components in the copolymer was iBEA / 2EHA / HEA = 77.1 / 11.1 / 11.8.

(Production Example 2) (Synthesis of acrylic copolymer (2))
2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile) (AMVN) 0.84 mg, 1-isobutoxyethyl acrylate (iBEA) 2.03 g, 2-ethylhexyl acrylate (2EHA) 0.45 g, A mixed solution of 0.08 g of 2-hydroxyethyl acrylate (HEA) and 2.56 g of ethyl acetate was put in a test tube and degassed by argon gas bubbling for 30 minutes. 3.11 μL of organic monotellurium compound is added to a test tube using a microsyringe and reacted for 5 hours in an oil bath at 50 ° C. to obtain a reaction solution of an acrylic copolymer (2) which is a random copolymer. It was. ^{From 1} H-NMR (300 MHz) analysis, the polymerization rate of 1-isobutoxyethyl acrylate was 69%, the polymerization rate of 2-ethylhexyl acrylate was 72%, and the polymerization rate of 2-hydroxyethyl acrylate was 70%.

  After completion of the reaction, the polymerization solution was diluted with 20 mL of ethyl acetate, poured into methanol: water (80:20 volume fraction) to precipitate the polymer, and the supernatant was removed by decantation. The resulting precipitate was dissolved in 50 mL of chloroform and poured into methanol: water (80:20 volume fraction) to reprecipitate the polymer. After removing the supernatant liquid by decantation, it was vacuum-dried at 40 ° C. under reduced pressure for 10 hours to obtain an acrylic copolymer (2) as a random copolymer. From GPC analysis, it was Mn = 105,400, Mw = 137,000, PD = 1.30. The mass ratio of the constituent components in the copolymer was iBEA / 2EHA / HEA = 75.6 / 20.2 / 4.2.

(Production Example 3) (Synthesis of acrylic copolymer (3))
2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile) (AMVN) 1.00 mg, 1-isobutoxyethyl acrylate (iBEA) 2.76 g, n-butyl acrylate (nBA) 0.46 g and A mixed solution of 3.21 g of ethyl acetate was placed in a test tube and degassed by argon gas bubbling for 30 minutes. 3.69 μL of organic monotellurium compound is added to a test tube using a microsyringe and reacted for 5 hours in an oil bath at 50 ° C. to obtain a reaction solution of an acrylic copolymer (3) which is a random copolymer. It was. ^{From 1} H-NMR (300 MHz) analysis, the polymerization rate of 1-isobutoxyethyl acrylate was 65%, and the polymerization rate of n-butyl acrylate was 61%.

  After completion of the reaction, the polymerization solution was diluted with 20 mL of ethyl acetate, poured into methanol: water (80:20 volume fraction) to precipitate the polymer, and the supernatant was removed by decantation. The resulting precipitate was dissolved in 50 mL of chloroform and poured into methanol: water (80:20 volume fraction) to reprecipitate the polymer. After removing the supernatant liquid by decantation, it was vacuum dried at 40 ° C. under reduced pressure for 10 hours to obtain an acrylic copolymer (3) which is a random copolymer. From the GPC analysis, it was Mn = 91,200, Mw = 129,500, PD = 1.42. The amount ratio of the constituent components in the copolymer was iBEA / nBA = 79.5 / 20.5.

(Production Example 4) (Synthesis of acrylic copolymer (4))
2,4′-azobis (4-methoxy-2,4-dimethylvaleronitrile) (AMVN) 1.04 mg, 1-isobutoxyethyl acrylate (iBEA) 2.93 g, 2-hydroxyethyl acrylate (HEA) 0.20 g A mixed solution of 3.12 g of ethyl acetate and ethyl acetate was put into a test tube and degassed by argon gas bubbling for 30 minutes. 3.84 μL of organic monotellurium compound is added to a test tube using a microsyringe and reacted for 5 hours in an oil bath at 50 ° C. to obtain a reaction solution of an acrylic copolymer (4) which is a random copolymer. It was. ^{From 1} H-NMR (300 MHz) analysis, the polymerization rate of 1-isobutoxyethyl acrylate was 80%, and the polymerization rate of 2-hydroxyethyl acrylate was 84%.
After completion of the reaction, the polymerization solution was diluted with 20 mL of ethyl acetate, poured into methanol: water (80:20 volume fraction) to precipitate the polymer, and the supernatant was removed by decantation. The resulting precipitate was dissolved in 50 mL of chloroform and poured into methanol: water (80:20 volume fraction) to reprecipitate the polymer. After removing the supernatant by decantation, it was vacuum-dried at 40 ° C. for 10 hours under reduced pressure to obtain an acrylic copolymer (4) as a random copolymer. From the GPC analysis, it was Mn = 103,500, Mw = 149,000, PD = 1.44. The mass ratio of the constituent components in the copolymer was iBEA / HEA = 88.2 / 11.8.

(Production Example 5) (Synthesis of acrylic copolymer (5))
2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile) (AMVN) 1.21 mg, 1-isobutoxyethyl acrylate (iBEA) 1.97 g, 2-ethylhexyl acrylate (2EHA) 1.37 g, A mixed solution of 0.30 g of 2-hydroxyethyl acrylate (HEA) and 3.63 g of ethyl acetate was placed in a test tube and degassed by argon gas bubbling for 30 minutes. 4.47 μL of organic monotellurium compound is added to a test tube using a microsyringe and reacted for 5 hours in an oil bath at 50 ° C. to obtain a reaction solution of an acrylic copolymer (5) which is a random copolymer. It was. ^{From 1} H-NMR (300 MHz) analysis, the polymerization rate of 1-isobutoxyethyl acrylate was 88%, the polymerization rate of 2-ethylhexyl acrylate was 86%, and the polymerization rate of 2-hydroxyethyl acrylate was 88%.

  After completion of the reaction, the polymerization solution was diluted with 20 mL of ethyl acetate, poured into methanol: water (80:20 volume fraction) to precipitate the polymer, and the supernatant was removed by decantation. The resulting precipitate was dissolved in 50 mL of chloroform and poured into methanol: water (80:20 volume fraction) to reprecipitate the polymer. After removing the supernatant liquid by decantation, it was vacuum dried at 40 ° C. under reduced pressure for 10 hours to obtain an acrylic copolymer (5) as a random copolymer. From the GPC analysis, it was Mn = 114,100, Mw = 176,900, PD = 1.55. The mass ratio of the constituent components in the copolymer was iBEA / 2EHA / HEA = 50.6 / 35.7 / 13.7.

(Production Example 6) (Synthesis of acrylic copolymer (6))
A mixed solution of 1.20 mg of 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile) (AMVN), 3.02 g of 1-isobutoxyethyl acrylate (iBEA) and 4.35 g of ethyl acetate was added to a test tube. And degassed by argon gas bubbling for 30 minutes. 4.47 μL of organic monotellurium compound was added to a test tube using a microsyringe, and reacted for 2 hours in an oil bath at 50 ° C. to obtain a reaction solution of poly 1-isobutoxyethyl acrylate (1). ^{From 1} H-NMR (300 MHz) analysis, the polymerization rate was 54%. Moreover, it was Mn = 54,200 and PD = 1.38 from the GPC analysis.
To the reaction solution of poly 1-isobutoxyethyl acrylate (1) obtained above, 0.79 g of 2-ethylhexyl acrylate (2EHA) and 2-hydroxyethyl acrylate (HEA) 0 which had been previously bubbled with argon gas for 30 minutes. .55 g of the mixed solution was added and reacted at 50 ° C. for 4 hours. ^{From 1} H-NMR (300 MHz) analysis, the polymerization rate of 1-isobutoxyethyl acrylate was 67%, the polymerization rate of 2-ethylhexyl acrylate was 39%, and the polymerization rate of 2-hydroxyethyl acrylate was 49%.

  After completion of the reaction, the polymerization solution was poured into methanol: water (80:20 volume fraction) to precipitate the polymer, and the supernatant was removed by decantation. The resulting precipitate was dissolved in 50 mL of chloroform and poured into methanol: water (80:20 volume fraction) to reprecipitate the polymer. After removing the supernatant by decantation, it is vacuum-dried at 40 ° C. for 10 hours under reduced pressure, and an acrylic that is a block copolymer composed of a poly-1-isobutoxyethyl acrylate chain and a polyacrylate chain composed of other copolymerization components. A system copolymer (6) was obtained. From the GPC analysis, it was Mn = 87,500, Mw = 126,900, PD = 1.45. The mass ratio of the constituent components in the copolymer was iBEA / 2EHA / HEA = 72.3 / 12.5 / 15.2.

(Production Example 7) (Synthesis of acrylic copolymer (7))
2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile) (AMVN) 3.84 mg, 2,2′-azobis (isobutyronitrile) (AIBN) 1.71 mg, 1-isobutoxyethyl A mixed solution of 3.00 g of acrylate (iBEA), 0.57 g of 2-ethylhexyl acrylate (2EHA), 0.24 g of 2-hydroxyethyl acrylate (HEA) and 3.81 g of anisole was placed in a test tube and bubbled with argon gas for 30 minutes. Was degassed. 2.12 μL of di-n-butyl ditelluride is added to a test tube using a microsyringe, and reacted for 5 hours in an oil bath at 60 ° C. to obtain a reaction solution of an acrylic copolymer (7) that is a random copolymer Got. ^{From 1} H-NMR (300 MHz) analysis, the polymerization rate of 1-isobutoxyethyl acrylate was 92%, the polymerization rate of 2-ethylhexyl acrylate was 85%, and the polymerization rate of 2-hydroxyethyl acrylate was 88%.

  After completion of the reaction, the polymerization solution was diluted with 20 mL of chloroform, poured into methanol: water (80:20 volume fraction) to precipitate the polymer, and the supernatant was removed by decantation. The resulting precipitate was dissolved in 50 mL of chloroform and poured into methanol: water (80:20 volume fraction) to reprecipitate the polymer. After removing the supernatant by decantation, it was vacuum-dried at 40 ° C. for 10 hours under reduced pressure to obtain an acrylic copolymer (7) as a random copolymer. From the GPC analysis, it was Mn = 109,000, Mw = 175,500, PD = 1.61. The amount ratio of the constituent components in the copolymer was iBEA / 2EHA / HEA = 72.5 / 13.5 / 14.0.

(Production Example 8) (Synthesis of acrylic copolymer (8))
2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile) (AMVN) 3.79 mg, 2,2′-azobis (isobutyronitrile) (AIBN) 1.70 mg, 1-isobutoxyethyl A mixed solution of 3.00 g of acrylate (iBEA), 0.57 g of 2-ethylhexyl acrylate (2EHA), 0.23 g of 2-hydroxyethyl acrylate (HEA) and 3.80 g of anisole was placed in a test tube and bubbled with argon gas for 30 minutes. Was degassed. 2.11 μL of di-n-butyl ditelluride is added to a test tube using a microsyringe and reacted for 9 hours in an oil bath at 60 ° C. to react a reaction solution of an acrylic copolymer (8) that is a random copolymer Got. ^{From 1} H-NMR (300 MHz) analysis, the polymerization rate of 1-isobutoxyethyl acrylate was 94%, the polymerization rate of 2-ethylhexyl acrylate was 96%, and the polymerization rate of 2-hydroxyethyl acrylate was 96%.

  After completion of the reaction, the polymerization solution was diluted with 20 mL of chloroform, poured into methanol: water (80:20 volume fraction) to precipitate the polymer, and the supernatant was removed by decantation. The resulting precipitate was dissolved in 50 mL of chloroform and poured into methanol: water (80:20 volume fraction) to reprecipitate the polymer. After removing the supernatant liquid by decantation, it was vacuum-dried at 40 ° C. under reduced pressure for 10 hours to obtain an acrylic copolymer (8) as a random copolymer. From the GPC analysis, it was Mn = 115,000, Mw = 197,800, PD = 1.72. The mass ratio of the constituent components in the copolymer was iBEA / 2EHA / HEA = 74.0 / 15.2 / 10.8.

(Production Example 9) (Synthesis of acrylic copolymer (9))
2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile) (AMVN) 3.49 mg, 2,2′-azobis (isobutyronitrile) (AIBN) 1.52 mg, 1-isobutoxyethyl A mixed solution of 2.80 g of acrylate (iBEA), 0.51 g of 2-ethylhexyl acrylate (2EHA), 0.16 g of 2-hydroxyethyl acrylate (HEA) and 3.50 g of anisole was put in a test tube, and argon gas was bubbled for 30 minutes. Was degassed. 1.92 μL of di-n-butyl ditelluride is added to a test tube using a microsyringe, and reacted for 5 hours in an oil bath at 60 ° C., thereby reacting a reaction solution of an acrylic copolymer (9) that is a random copolymer Got. ^{From 1} H-NMR (300 MHz) analysis, the polymerization rate of 1-isobutoxyethyl acrylate was 94%, the polymerization rate of 2-ethylhexyl acrylate was 95%, and the polymerization rate of 2-hydroxyethyl acrylate was 93%.

  After completion of the reaction, the polymerization solution was diluted with 20 mL of chloroform, poured into methanol: water (80:20 volume fraction) to precipitate the polymer, and the supernatant was removed by decantation. The resulting precipitate was dissolved in 50 mL of chloroform and poured into methanol: water (80:20 volume fraction) to reprecipitate the polymer. After removing the supernatant liquid by decantation, it was vacuum-dried at 40 ° C. for 10 hours under reduced pressure to obtain an acrylic copolymer (9) which is a random copolymer. From GPC analysis, it was Mn = 105,000, Mw = 184,800, PD = 1.76. The mass ratio of the constituent components in the copolymer was iBEA / 2EHA / HEA = 77.4 / 14.3 / 8.3.

(Production Example 10) (Synthesis of acrylic copolymer (10))
2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile) (AMVN) 4.05 mg, 2,2′-azobis (isobutyronitrile) (AIBN) 1.76 mg, 2-tetrahydropyranyl A mixed solution of 1.80 g of acrylate (THPA), 1.41 g of 2-ethylhexyl acrylate (2EHA), 0.36 g of 2-hydroxyethyl acrylate (HEA) and 3.56 g of anisole is placed in a test tube, and an argon gas bubbling is performed for 30 minutes. Was degassed. 2.20 μL of di-n-butylditelluride is added to a test tube using a microsyringe, and reacted for 20 hours in an oil bath at 60 ° C. to react a reaction solution of an acrylic copolymer (10) that is a random copolymer Got. ^{From 1} H-NMR (300 MHz) analysis, the polymerization rate of 2-tetrahydropyranyl acrylate was 94%, the polymerization rate of 2-ethylhexyl acrylate was 98%, and the polymerization rate of 2-hydroxyethyl acrylate was 93%.

  After completion of the reaction, the polymerization solution was diluted with 20 mL of chloroform, poured into methanol: water (80:20 volume fraction) to precipitate the polymer, and the supernatant was removed by decantation. The resulting precipitate was dissolved in 50 mL of chloroform and poured into methanol: water (80:20 volume fraction) to reprecipitate the polymer. After removing the supernatant by decantation, it was vacuum-dried at 40 ° C. for 10 hours under reduced pressure to obtain an acrylic copolymer (10) as a random copolymer. From the GPC analysis, it was Mn = 77,000, Mw = 131,700, PD = 1.71. The mass ratio of the constituent components in the copolymer was THPA / 2EHA / HEA = 44.3 / 34.6 / 21.1.

(Comparative Production Example 1) (Synthesis of acrylic copolymer (H1))
2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile) (AMVN) 0.91 mg, n-butyl acrylate (tBA) 7.83 g, 2-hydroxyethyl acrylate (HEA) 1.69 g and acetic acid A mixed solution of 9.53 g of ethyl was put into a test tube and deaerated by bubbling with argon gas for 30 minutes. 3.36 μL of organic monotellurium compound was added to the test tube using a microsyringe, and reacted in an oil bath at 50 ° C. for 3.5 hours. ^{From 1} H-NMR (300 MHz) analysis, the polymerization rate of n-butyl acrylate was 64%, and the polymerization rate of 2-hydroxyethyl acrylate was 75%.

  After completion of the reaction, the polymerization solution was diluted with 20 mL of chloroform, the polymerization solution was poured into methanol: water (80:20 volume fraction) to precipitate the polymer, and the supernatant was removed by decantation. The resulting precipitate was dissolved in 40 mL of chloroform and poured into methanol: water (80:20 volume fraction) to reprecipitate the polymer. After removing the supernatant by decantation, it was vacuum-dried at 40 ° C. for 10 hours under reduced pressure to obtain an acrylic copolymer (H1) as a random copolymer. From the GPC analysis, it was Mn = 318,000, Mw = 617,000, PD = 1.94. The mass ratio of the constituent components in the copolymer was nBA / HEA = 74.2 / 25.8.

(Comparative Production Example 2) (Synthesis of acrylic copolymer (H2))
2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile (AMVN) 0.49 mg, t-butyl acrylate (tBA) 1.00 g, 2-ethylhexyl acrylate (2EHA) 1.63 g, 2-hydroxyethyl A mixed solution of 0.40 g of acrylate (HEA) and 3.01 g of ethyl acetate was put in a test tube and degassed by argon gas bubbling for 30 minutes.The organic monotellurium compound was added to the test tube using a microsyringe, and 50 The reaction was carried out for 2 hours in an oil bath at 0 ° C. From ¹ H-NMR (300 MHz) analysis, the polymerization rate of t-butyl acrylate was 77%, the polymerization rate of 2-ethylhexyl acrylate was 73%, and the polymerization of 2-hydroxyethyl acrylate The rate was 81%.
After completion of the reaction, the polymerization solution was diluted with 20 mL of chloroform, poured into methanol: water (80:20 volume fraction) to precipitate the polymer, and the supernatant was removed by decantation. The resulting precipitate was dissolved in 50 mL of chloroform and poured into methanol: water (80:20 volume fraction) to reprecipitate the polymer. After removing the supernatant liquid by decantation, it was vacuum dried at 40 ° C. under reduced pressure for 10 hours to obtain an acrylic copolymer (H2) which is a random copolymer. From the GPC analysis, it was Mn = 285,700, Mw = 580,000, PD = 2.03. The mass ratio of the constituent components in the copolymer was tBA / 2EHA / HEA = 38.7 / 42.1 / 19.2.

(Comparative Production Example 3) (Synthesis of acrylic copolymer (H3))
A mixed solution of 0.86 mg of 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile (AMVN), 1.46 g of t-butyl acrylate (tBA) and 1.46 g of ethyl acetate was placed in a test tube, and 30 The organic monotellurium compound (3.2 μL) was added to the test tube using a microsyringe and reacted in an oil bath at 50 ° C. for 2 hours to react poly t-butyl acrylate (1). From ¹ H-NMR (300 MHz) analysis, the polymerization rate was 79%, and from GPC analysis, Mn = 73,800 and PD = 1.28.

2.48 g of 2-ethylhexyl acrylate (2EHA) and 0.82 g of 2-hydroxyethyl acrylate (HEA) obtained by performing bubbling with argon gas for 30 minutes in advance to the reaction solution of poly t-butyl acrylate (1) obtained above. Then, a mixed solution of 5.30 g of ethyl acetate was added and reacted at 50 ° C. for 7 hours. ^{From 1} H-NMR (300 MHz) analysis, the polymerization rate of t-butyl acrylate was 82%, the polymerization rate of 2-ethylhexyl acrylate was 49%, and the polymerization rate of 2-hydroxyethyl acrylate was 58%.

  After completion of the reaction, the polymerization solution was poured into methanol: water (80:20 volume fraction) to precipitate the polymer, and the supernatant was removed by decantation. The resulting precipitate was dissolved in 50 mL of chloroform and poured into methanol: water (80:20 volume fraction) to reprecipitate the polymer. After removing the supernatant liquid by decantation, it was vacuum dried at 40 ° C. for 10 hours under reduced pressure to obtain an acrylic copolymer (H3) as a block copolymer. From the GPC analysis, it was Mn = 265,000, Mw = 4611,100, PD = 1.74. The mass ratio of the constituent components in the copolymer was tBA / 2EHA / HEA = 34.5 / 47.0 / 18.5.

Example 1
The acrylic copolymer (1) obtained in Production Example 1 was diluted with toluene to obtain a pressure-sensitive adhesive composition comprising a 15 wt% toluene solution. The obtained pressure-sensitive adhesive composition was applied onto a PET film having a thickness of 50 μm using an applicator having a gap of 8 milli-inch and dried under reduced pressure for 12 hours to prepare a pressure-sensitive adhesive sheet.

(Example 2 (Reference Example 1) )
A pressure-sensitive adhesive composition was prepared in the same manner as in Example 1 except that the acrylic copolymer (2) obtained in Production Example 2 was used instead of the acrylic copolymer (1). About the obtained adhesive composition, it carried out similarly to Example 1, and created the adhesive sheet.

(Example 3 (Reference Example 2) )
A pressure-sensitive adhesive composition was prepared in the same manner as in Example 1 except that the acrylic copolymer (3) obtained in Production Example 3 was used instead of the acrylic copolymer (1). About the obtained adhesive composition, it carried out similarly to Example 1, and created the adhesive sheet.

Example 4
A pressure-sensitive adhesive composition was prepared in the same manner as in Example 1 except that the acrylic copolymer (4) obtained in Production Example 4 was used instead of the acrylic copolymer (1). About the obtained adhesive composition, it carried out similarly to Example 1, and created the adhesive sheet.

(Example 5)
A pressure-sensitive adhesive composition was prepared in the same manner as in Example 1 except that the acrylic copolymer (5) obtained in Production Example 5 was used instead of the acrylic copolymer (1). About the obtained adhesive composition, it carried out similarly to Example 1, and created the adhesive sheet.

(Example 6)
A pressure-sensitive adhesive composition was prepared in the same manner as in Example 1 except that the acrylic copolymer (6) obtained in Production Example 6 was used instead of the acrylic copolymer (1). About the obtained adhesive composition, it carried out similarly to Example 1, and created the adhesive sheet.

(Example 7)
A pressure-sensitive adhesive composition was prepared in the same manner as in Example 1 except that the acrylic copolymer (7) obtained in Production Example 7 was used instead of the acrylic copolymer (1). About the obtained adhesive composition, it carried out similarly to Example 1, and created the adhesive sheet.

(Example 8)
A pressure-sensitive adhesive composition was prepared in the same manner as in Example 1 except that the acrylic copolymer (8) obtained in Production Example 8 was used instead of the acrylic copolymer (1). About the obtained adhesive composition, it carried out similarly to Example 1, and created the adhesive sheet.

(Example 9 (Reference Example 3) )
A pressure-sensitive adhesive composition was prepared in the same manner as in Example 1 except that the acrylic copolymer (9) obtained in Production Example 9 was used instead of the acrylic copolymer (1). About the obtained adhesive composition, it carried out similarly to Example 1, and created the adhesive sheet.

(Example 10)
A pressure-sensitive adhesive composition was prepared in the same manner as in Example 1 except that the acrylic copolymer (10) obtained in Production Example 10 was used instead of the acrylic copolymer (1). About the obtained adhesive composition, it carried out similarly to Example 1, and created the adhesive sheet.

(Comparative Example 1)
A pressure-sensitive adhesive composition was prepared in the same manner as in Example 1 except that instead of the acrylic copolymer (1), the acrylic copolymer (H1) obtained in Comparative Production Example 1 was used. . About the obtained adhesive composition, it carried out similarly to Example 1, and created the adhesive sheet.

(Comparative Example 2)
A pressure-sensitive adhesive composition was prepared in the same manner as in Example 1, except that the acrylic copolymer (H2) obtained in Comparative Production Example 2 was used instead of the acrylic copolymer (1). . About the obtained adhesive composition, it carried out similarly to Example 1, and created the adhesive sheet.

(Comparative Example 3)
A pressure-sensitive adhesive composition was prepared in the same manner as in Example 1 except that the acrylic copolymer (H3) obtained in Comparative Production Example 3 was used in place of the acrylic copolymer (1). . About the obtained adhesive composition, it carried out similarly to Example 1, and created the adhesive sheet.

  The following evaluation was performed about the adhesive sheet obtained by the said Example and comparative example. The results obtained are shown in the table.

<Disassembly test>
Cut the adhesive sheet into strips with a width of 20 mm and a length of 250 mm, and place a hand roller with a weight of 2 kg on a SUS plate with a width of 50 mm, a length of 150 mm and a thickness of 0.5 mm in an environment of 23 ° C. and 50% RH. Two similar test pieces were prepared by reciprocating two times.
One of the pressure-bonded test pieces was left to stand in an environment of 23 ° C. and 50% RH for 1 hour, and then peeled off at a rate of 30 mm / min using a tensile tester, and the 180 ° peel strength was measured (initial). .
One of the pressure-bonded test pieces was allowed to stand in a 23 ° C. and 50% RH environment for 30 minutes, then heated in 100 ° C. hot water for 10 minutes and then allowed to cool to 23 ° C. (about 30 minutes) (hot water) .
About these test pieces, it peeled off at the speed | rate of 30 mm / min using the tensile tester, and measured 180 degree peel strength. In the table, the average value of the peel strength measured at a peel distance of 30 to 120 mm is shown.
In addition, the irradiation with ultraviolet rays uses a Toshiba physics and chemistry mercury lamp “SHL-100UVQ-2” (75 W) as a light source, and the distance between the light source and the sample is 10 cm. (Irradiation under the same conditions in the following examples and comparative examples).

  As shown in the above table, the pressure-sensitive adhesive tapes of the present invention of Examples 1 to 10 can be adhered to the adherend and can be suitably disassembled by immersion in hot water. Among them, the adhesive tapes of Examples 1, 4, and 6 to 8 are preferably peeled off at least one of the adhesive layer / adherent interface and the adhesive layer / substrate interface, No adhesive residue was found on the substrate, and the film had suitable interfacial peelability. On the other hand, the pressure-sensitive adhesive tapes of Comparative Examples 1 to 3 were poor in dismantling properties by hot water immersion.

  According to the pressure-sensitive adhesive composition of the present invention, it can be attached to an adherend, and can be easily disassembled by being immersed in warm water during disassembly. Therefore, it is suitable for OA equipment, IT / household appliances, automobiles, etc. used for recycling and reuse, for parts fixing, parts temporarily fixing, labels for displaying product information, etc. And can be easily disassembled by immersion in warm water during disassembly. Moreover, since it can be easily disassembled with hot water, expensive dismantling facilities and lines are not required, and a large amount of dismantling can be performed efficiently, and dismantling work can be realized easily and at low cost.

Claims (4)

Containing an acrylic copolymer containing 20 to 90 mol% of (meth) acrylate obtained by reacting (meth) acrylic acid and vinyl ether in the monomer component ;
The acrylic copolymer contains (meth) acrylate having 1 to 14 carbon atoms and a hydroxyl group-containing monomer as monomer components,
Content of the said hydroxyl-containing monomer is 10 mol% or more in the monomer component which comprises the said acrylic copolymer, The adhesive composition characterized by the above-mentioned . The pressure-sensitive adhesive composition according to claim 1 , wherein the (meth) acrylate having an alkyl group having 1 to 14 carbon atoms is n-butyl acrylate or 2-ethylhexyl acrylate. The content of the (meth) (meth) acrylates obtained by reacting an acrylic acid and vinyl ethers are, according to claim 1 or 2 which is 60～90Mol% of the monomer components constituting the acrylic copolymer Adhesive composition. It has an adhesive layer which consists of an adhesive composition of any one of Claims 1-3 , The easily disassembleable adhesive tape characterized by the above-mentioned.