Polymer, adhesive composition containing the polymer, and laminate

Abstract

To provide a degradable polymer that can enhance bonding strength by simple treatment after the bonding, and an adhesive composition including the polymer.SOLUTION: A polymer includes a monomer unit derived from a monomer represented by a specific formula, and has a mass average molecular weight of 250,000 or more and 2,000,000 or less in terms of polymethyl methacrylate, measured by gel permeation chromatography.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention has stimulus responsiveness and can strengthen the bonding strength by performing a simple treatment after bonding. The present invention relates to a polymer capable of forming a polymeric adhesive and an adhesive composition comprising said polymer. [Background technology]

[0002] Due to various industrial demands, stimuli-responsive polymers have been attracting attention in various fields. The polymer used for bonding can be easily bonded by applying a stimulus at any time after bonding. Temporary adhesive technology that increases bonding strength is expected to improve reworkability and manufacturing yield. are. Patent Document 1 describes a method for adding epoxy resin and a cationic polymerization catalyst to a photocurable acrylic adhesive. The curable adhesive material is coated on a substrate and then photocured. The adhesive tape obtained by the curing has stimulus-responsiveness. Although rework such as position adjustment is possible, the adhesive strength can be improved by heating and curing in a post-process. However, the adhesive tape described in Patent Document 1 The curing shrinkage occurs due to the crosslinking of the epoxy resin during the heat curing process. The bridging method had drawbacks such as dimensional stability, which limited its practical use.

[0003] Patent Document 2 describes a (meth)acrylic acid obtained by reacting (meth)acrylic acid with a vinyl ether. ) Acrylic copolymer containing 20 to 90 mol% of acrylate in the monomer component The adhesive composition is characterized by having a warm water responsive property. It has the property of being easily dismantled by immersing it in warm water after being applied to the adherend. Patent Document 1 discloses a (meth)acrylic acid copolymer obtained by reacting (meth)acrylic acid with a vinyl ether. It has been shown that decomposition of the acrylate moiety contributes to degradability.

[0004] Decomposition in response to stimuli, such as the decomposable acrylic copolymer described in Patent Document 2, This method is convenient and desirable for functional expression, but on the other hand, it is difficult to use such degradable polymers. There is no mention of any application of temporary adhesion technology, and no mention of improving bonding strength by stimuli response. It was unclear whether this could be applied to the case study. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-288418 [Patent Document 2] International Publication No. 2014 / 157620 [Non-Patent Document 1] Polymer,64(2015),260-267. Summary of the Invention [Problem to be solved by the invention]

[0006] The object of the present invention is to provide a degradable adhesive that can strengthen the bonding strength by simple treatment after bonding. The object of the present invention is to provide a polymer of the present invention, and to provide an adhesive composition containing the polymer. do. [Means for solving the problem]

[0007] That is, the present invention is summarized as follows [1] to [8]. [1] Derived from a monomer represented by the following formula (a): Building blocksand having a weight average molecular weight of 250,000 or more and 2,000,000 or less in terms of polymethyl methacrylate as measured by gel permeation chromatography.

[0008] [ka]

[0009] (In the formula (a), O represents an oxygen atom, X represents an oxygen atom, a sulfur atom, or N(R 14 ) and N is a nitrogen atom, R 14 represents a hydrogen atom or an alkyl group, and Z represents a hydrogen atom or a methyl group. and R 1 and R 2 represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms. [2] 10% thermal weight loss temperature measured by a differential thermal and thermogravimetric simultaneous measurement device is 140°C or more for 30 The polymer according to [1], wherein the temperature is 0°C or lower. [3] The glass transition temperature measured by differential calorimetry is between -50°C and 0°C. [1 ] or the polymer according to [2]. [4] The molecular weight distribution in terms of PMMA measured by gel permeation chromatography is 2.5 or more. The polymer according to any one of [1] to [3], wherein the polymer has a viscosity of from 0.1 to 8.0. [5] The monomer represented by the formula (a) is represented by the following formula (1), the following formula (2) and the following formula (3): The polymer according to any one of [1] to [4], which is represented by at least one of the following:

[0010] [ka]

[0011] (wherein X is an oxygen atom, a sulfur atom, or NR 14 N represents a nitrogen atom, and R 14 represents a hydrogen atom or an alkyl group, Z represents a hydrogen atom or a methyl group, and R1 and R 2 each represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and R 3 and R 5 each represents an alkyl group, a cycloalkyl group, or an aryl group having 1 to 20 carbon atoms; R 4 and R 6 Each represents an alkylene group having 1 to 10 carbon atoms. [6] The ratio of the monomer represented by formula (a) to the structural units derived from all the monomers constituting the polymer Building blocks The polymer according to any one of [1] to [5], wherein the proportion of is 20% by mass or more and 90% by mass or less. [7] An adhesive composition comprising the polymer according to any one of [1] to [6]. [8] A laminate comprising a layer containing the adhesive composition according to [7] and at least one metal layer in contact with the layer. [Effects of the Invention]

[0012] According to the present invention, a degradable adhesive can be obtained that can strengthen the bonding strength by a simple treatment after bonding. It is also possible to provide an adhesive composition containing the polymer. can. DETAILED DESCRIPTION OF THE INVENTION

[0013] In the present invention, the term "structural unit" refers to a chemical unit formed directly from a monomer by a polymerization reaction. The polymer obtained by the polymerization reaction is treated with a chemical reaction to form a polymer. It means a chemical structure in which a part of the structure of the constituent unit of the polymer is converted into another structure. The term "monomer" refers to a compound having polymerizability (polymerizable monomer). "(Meth)acrylate" is a general term for acrylate and methacrylate. "(Meth)acrylic copolymer" refers to a copolymer in which at least some of the constituent units are (meth)acrylic units. It means a copolymer whose constituent units are derived from a monomer. "Polymethyl methacrylate" is a polymer in which at least 95% by mass of the constituent units are methyl methacrylate. This refers to a polymer whose structural units are derived from vinyl monomers, and will hereinafter also be referred to as PMMA.

[0014] [Polymer] The polymer of the present invention is derived from a monomer represented by the following formula (a): Building blocks The 10% thermal weight loss temperature measured with a thermogravimetric and differential thermal analyzer is preferably 140°C or higher and 300°C or lower. Usually derived from (meth)acrylic acid esters Building blocks In polymers having the formula (I), thermal weight loss is rarely observed at temperatures below 300°C due to the thermal stability of the repeating units derived from the ethylenically unsaturated bonds of the monomer. However, if the ester structure of the monomer units derived from (meth)acrylic acid ester has poor thermal stability, thermal weight loss may be observed even at temperatures below 300°C due to decomposition of the ester structure, i.e., side chain decomposition.

[0015] Monomers derived from (meth)acrylic acid esters that can cause side chain decomposition (hereinafter, such Monomer (hereinafter referred to as "monomer A"), for example, a monomer represented by the following formula (a) at the ester moiety Structure and (meth)acrylates in which a carboxy group is generated by β-hydrogen elimination or hydrolysis of the ester moiety.

[0016] [ka]

[0017] (In the formula (a), O represents an oxygen atom, X represents an oxygen atom, a sulfur atom, or N(R 14 ) and N is a nitrogen atom, R 14 represents a hydrogen atom or an alkyl group, and Z represents a hydrogen atom or a methyl group. and R 1 and R 2 represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms. The monomer A is preferably a monomer represented by the formula (a) in that it is easy to obtain side chain degradability. and the monomer represented by formula (a) is preferably a monomer represented by the following formula (1), the following formula (2) or the following formula ( It is more preferable that the compound is represented by at least one of the following:

[0018] [ka]

[0019] (wherein X is an oxygen atom, a sulfur atom, or NR 14 N represents a nitrogen atom, and R 14 is water represents a hydrogen atom or an alkyl group, Z represents a hydrogen atom or a methyl group, R 1 and R 2 is that Each of them represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and R 3 and R 5 are carbon represents an alkyl group, a cycloalkyl group, or an aryl group having 1 to 20 carbon atoms; R 4 and R 6 is that Each of these represents an alkylene group having 1 to 10 carbon atoms.) X is an oxygen atom (an ether-type oxygen atom; -O-), a sulfur atom (a sulfide-type sulfur atom; -S-), N(R 14 ) (N represents a nitrogen atom, R 14 represents a hydrogen atom or an alkyl group ) may be used, but among these, those containing an oxygen atom are preferred in that they are easy to decompose into side chains. That is, it is preferable to have an acetal structure in which X in formula (a) is O.

[0020] Z may be either a hydrogen atom or a methyl group, but the bonding strength increases when the side chain is decomposed. In terms of ease of use, a methyl group is preferred, i.e., methacrylate is preferred. In formula (1), R 1 and R2 Examples of the alkyl group having 1 to 10 carbon atoms include methyl ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, pentyl group, Examples include a hexyl group and a 2-ethylhexyl group.

[0021] The branched acetal structure may be an isopropyl group, an isopropyl group, or an isopropyl group. Examples include a butyl group and a 2-ethylhexyl group. R 1 and R 2 The number of carbon atoms in the alkyl group is preferably 1 to 4 in terms of side chain decomposition, and 1 to 3 is more preferable, and 1 or 2 is even more preferable. R 1 and R 2 Preferred combinations include a combination of a hydrogen atom and a methyl group, a combination of a methyl group and a hydrogen atom; and an alkyl group having 2 to 10 carbon atoms (hereinafter referred to as "long alkyl group"). A combination of a methyl group and a long-chain alkyl group may be referred to as a "long-chain alkyl group." a combination of a hydrogen atom and a hydrogen atom; a combination of a long-chain alkyl group and a long-chain alkyl group; Among these, in terms of side chain decomposition, a combination of a hydrogen atom and a methyl group is preferred. A combination of is preferred.

[0022] R 3 In the formula (I), the alkyl group having 1 to 20 carbon atoms is the alkyl group having 1 to 10 carbon atoms. Examples of the alkyl group include the alkyl groups listed above, a decyl group, a dodecyl group, and a tetradecyl group. Also, R 3 Examples of the cycloalkyl group in cycloheptyl group, cyclooctyl group, cyclodecyl group, cyclododecyl group, etc. can be.

[0023] Also, R 3Examples of the aryl group in the formula (I) include a phenyl group and a naphthyl group. R 3 The alkyl group, cycloalkyl group, and aryl group in groups, aryl groups, alkoxy groups, alkanoyloxy groups, aralkyl groups, and acetoxy groups When the alkyl group has a substituent, the number of the substituents is It may be one or two or more.

[0024] The cycloalkyl group and aryl group as the substituents each include the same substituents as those described above. Examples of the alkoxy group include a methoxy group, an ethoxy group, a propoxy group, and a butoxy group. Examples of the alkanoyloxy group include an ethanoyloxy group. Examples of the alkyl group include a benzyl group. In formula (2), R 4 The alkylene group having 1 to 10 carbon atoms in the formula (I) is, for example, a methylene group. ethylene group, propylene group, butylene group, hexylene group, etc.

[0025] In terms of side chain degradability, R 4 The alkylene group preferably has 2 to 7 carbon atoms, and more preferably has 3 to 4 carbon atoms. is more preferred. The alkylene group may be a cycloalkyl group, an aryl group, an alkoxyl group, an alkanoyl group, or the like. substituted with a substituent selected from the group consisting of an oxy group, an aralkyl group, and an acetoxy group; When substituted with a substituent, the number of the substituents may be one or two or more. Specific examples of the substituent that may be substituted on the alkylene group include R 3 and the substituents in The same substituents are mentioned.

[0026] The cyclic acetal structure may be a cycloalkyl group, an aryl group, or an alkylene group. Examples include a aryl group. In formula (3), R 5 is R in Eq. (1) 3 The same substituents as those listed above are also included, and the preferred embodiments are also the same. R 6 is R in Equation (2). 4 In terms of side chain decomposability, the same substituents as those in The same applies to the situation.

[0027] In the polymer of the present invention, the structure derived from the (meth)acrylate monomer A is such that side chain decomposition occurs. By doing so, it is possible to increase the bonding strength at any time. The glass transition temperature Tg of the polymer increases more when the side chain is decomposed. This makes it easier to improve the bonding strength of an adhesive composition containing the polymer after it responds to a stimulus. Generally, the glass transition temperature Tg of a polymer is determined by the glass transition temperature of the homopolymer of the constituent monomers. The mass ratio of the monomer can be calculated from the mass ratio and the mass proportion of the monomer by the Fox formula described later. If monomer A is methacrylate (CH2=C(CH3)-COO-), the side chain is decomposed. When this occurs, the structure changes to that derived from methacrylic acid (CH2=C(CH3)-COOH). If the monomer A is an acrylate (CH2=CH-COO-), when the side chain is decomposed, It changes to a structure derived from acrylic acid (CH2=CH-COOH).

[0028] The glass transition temperature Tg of the homopolymer of methacrylic acid is 228°C, and that of the homopolymer of acrylic acid is 228°C. The glass transition temperature Tg of The glass transition temperature Tg of the polymer after side chain decomposition is The adhesiveness after the stimulus response is significantly increased when the monomer A is methacrylate. This makes it easier to improve the bonding strength of the composition.

[0029] Among the monomers A, examples of the monomer represented by formula (a) include the following (meta) Acrylates are examples.

[0030] [ka]

[0031] These monomers A may be purchased commercially or may be appropriately synthesized using known methods. A compound obtained by the above method may also be used. The monomer other than the monomer A constituting the polymer of the present invention may be a monomer copolymerizable with the monomer A. There are no particular limitations on the monomers as long as they are usable, and various monomers can be used as needed. For example, Methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate acrylate, i-propyl (meth)acrylate, n-butyl (meth)acrylate, i- Butyl (meth)acrylate, t-butyl (meth)acrylate, 2-ethylhexyl ( (meth)acrylate, n-lauryl (meth)acrylate, n-stearyl (meth)acrylate acrylate, benzyl (meth)acrylate, cyclohexyl (meth)acrylate, phenyl Isobornyl (meth)acrylate, Isobornyl (meth)acrylate, 2-Methoxyethyl ( meth)acrylate, 2-ethoxyethyl (meth)acrylate, phenoxyethyl (meth)acrylate (meth)acrylates such as methacrylate; 2-Hydroxyethyl (meth)acrylate, 2-Hydroxypropyl (meth)acrylate acrylate, 4-hydroxybutyl (meth)acrylate, glycerol (meth)acrylate hydroxyl group-containing (meth)acrylates such as acrylate; (Meth)acrylic acid, 2-(meth)acryloyloxyethylhexahydrophthalic acid, 2-(meth)acryloyloxypropylhexahydrophthalic acid, 2-(meth)acrylo 2-(meth)acryloyloxyethyl phthalate, 2-(meth)acryloyloxypropyl phthalate, 2-( Meth)acryloyloxyethyl maleate, 2-(meth)acryloyloxypropyl Maleic acid, 2-(meth)acryloyloxyethyl succinate, 2-(meth)acryloyl Peroxypropylsuccinic acid, Crotonic acid, Fumaric acid, Maleic acid, Itaconic acid, Maleic carboxyl group-containing vinyl monomers such as monomethyl acrylate and monomethyl itaconate; Vinyl monomers containing an acid anhydride group, such as maleic anhydride and itaconic anhydride; Glydisil (meth)acrylate, Glydisil α-ethyl acrylate, 3,4-epoxy Epoxy group-containing vinyl monomers such as butyl (meth)acrylate; Dimethylaminoethyl (meth)acrylate, Diethylaminoethyl (meth)acrylate vinyl monomers of amino group-containing (meth)acrylates such as acrylates; (Meth)acrylamide, Nt-butyl (meth)acrylamide, N-methylol ( (meth)acrylamide, N-methoxymethyl (meth)acrylamide, N-butoxymethyl (meth)acrylamide, diacetone acrylamide, maleic acid amide, maleimide vinyl monomers containing an amide group, such as amide; Styrene, α-methylstyrene, vinyltoluene, (meth)acrylonitrile, vinyl chloride vinyl monomers such as vinyl, vinyl acetate, and vinyl propionate; Divinylbenzene, ethylene glycol di(meth)acrylate, 1,3-butylene glycol Lithium di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, Triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate Acrylate, tripropylene glycol di(meth)acrylate, trimethylolpropane Panthenyl (meth) acrylate, allyl (meth) acrylate, N,N'-methylenebis and polyfunctional vinyl monomers such as (meth)acrylamide.

[0032] These may be used alone or in combination of two or more. Among these, the ease of obtaining the monomer and the ease of adjusting the glass transition temperature of the polymer are the main reasons. In terms of ease of use, (meth)acrylates and hydroxyl group-containing (meth)acrylates are preferred. Examples of (meth)acrylates and hydroxyl group-containing (meth)acrylates include methyl (Meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate butyl (meth)acrylate, n-butyl (meth)acrylate, t-butyl (meth)acrylate, 2-ethylhexyl 2-hydroxyethyl (meth)acrylate is more preferred. These acrylates are more preferred in that they are less likely to cause adhesion problems and are more likely to satisfy the required bonding strength.

[0033] The glass transition temperature of the polymer of the present invention is −50° C. or higher, preferably −45° C. or higher, The glass transition temperature of the polymer of the present invention is preferably 0°C or lower. The temperature is preferably −20° C. or lower, and more preferably −30° C. or lower. If the glass transition temperature of the polymer of the present invention is -50°C or higher, the polymer can be handled at room temperature. When the glass transition temperature of the polymer of the present invention is 0°C or lower, the polymer When an adhesive composition containing the compound is prepared, the adhesive composition has excellent bonding strength. The glass transition temperature was calculated from the Fox formula.

[0034]

number

[0035] Tg: Glass transition temperature of the copolymer (K) Tga: Glass transition temperature of the homopolymer of monomer A (K) Wa: weight fraction of monomer A Tgb: Glass transition temperature of the homopolymer of monomer B (K) Wb: weight fraction of monomer B Tgn: Glass transition temperature (K) of the homopolymer of monomer N Wn: weight fraction of monomer N (Wa+Wb+…+Wn=1) That is, the glass transition temperature when each of the monomers constituting the polymer is made into a homopolymer is The values ​​were calculated by applying the concentration and weight fraction to the Fox formula. The glass transition temperature of each of these monomers as a homopolymer is usually measured by a differential scanning calorimeter (D SC).

[0036] The 10% thermal weight loss temperature of the polymer of the present invention is preferably 140°C or higher, more preferably 160°C or higher. The 10% thermal weight loss temperature of the polymer of the present invention is more preferably 180°C or higher, and even more preferably 180°C or higher. The temperature is preferably 300°C or less, more preferably 280°C or less, and even more preferably 260°C or less. stomach. If the 10% thermal weight loss temperature of the polymer of the present invention is 140°C or higher, the durability and stinging property of the polymer are improved. The polymer of the present invention has a 10% thermal weight loss temperature of 300°C or less. This reduces the risk of simultaneous degradation of the polymer's main chain and side chains, ensuring stimuli responsiveness. Cheap.

[0037] The weight average molecular weight (Mw) of the polymer of the present invention is 250,000 or more, and is 280,000 or more. The mass of the polymer of the present invention is preferably 0.00 or more, and more preferably 300,000 or more. The average molecular weight is 2,000,000 or less, preferably 1,750,000 or less, and , 500,000 or less is more preferable. When the weight average molecular weight of the polymer of the present invention is 250,000 or more, the side chain The polymer of the present invention has excellent bonding strength after decomposition. If the above ratio is less than 1, the coating property onto the substrate is excellent.

[0038] The molecular weight distribution (Mw / Mn) of the polymer of the present invention is preferably 2.5 or more, and more preferably 2.7 or more. The molecular weight distribution of the polymer of the present invention is more preferably 8.0 or more, and even more preferably 2.9 or more. Preferably, it is 7.0 or less, more preferably 7.0 or less, and even more preferably 6.0 or less. If the molecular weight distribution of the polymer of the present invention is 2.5 or more, it is considered to be an adhesive composition containing the polymer. In this case, the bonding strength at the time of temporary bonding after the stimulus response is likely to be improved. If the ratio is 0.0 or less, the bonding strength after side chain decomposition in response to stimuli is excellent.

[0039] The mass average molecular weight and molecular weight distribution of the polymer of the present invention can be determined, for example, by gel permeation chromatography. By gel permeation chromatography (GPC), the polymethyl methacrylate (PMMA) equivalent, i.e., PMMA A calibration curve was prepared using the above as a standard substance, and measurements were carried out to determine the value. The ratio of the constituent units derived from the monomer A to the total monomer-derived constituent units constituting the polymer of the present invention The proportion of the amount is preferably 20% by mass or more, more preferably 25% by mass or more, and more preferably 30% by mass or more. The above is more preferable. In addition, the precursor to the structural units derived from all the monomers constituting the polymer of the present invention is The proportion of the structural units derived from the monomer A is preferably 90% by mass or less, more preferably 80% by mass or less. It is preferably 70 mass % or less, and more preferably 70 mass % or less.

[0040] When the proportion of the structural units derived from the monomer A in the polymer of the present invention is 20% by mass or more, The polymer of the present invention has excellent bonding strength after the side chain is decomposed in response to a stimulus. When the proportion of the original structural unit is 90 mass % or less, the stimuli when formed into an adhesive composition containing the polymer are The bonding strength before the sudden response shows a moderate value.

[0041] [Polymer manufacturing method] The method for producing a polymer according to the present invention comprises polymerizing a monomer mixture containing the monomer A. The method includes the steps of: The polymerization reaction method is not particularly limited, and may be solution polymerization, suspension polymerization, emulsion polymerization, bulk polymerization, etc. A variety of methods can be used. Among these, the reaction can be carried out while maintaining the homogeneity of the reaction solution until the late stage of polymerization. In this respect, solution polymerization is preferred.

[0042] In the method for producing a polymer of the present invention, the heat removal efficiency is improved by adding a mixture of monomers to a reaction vessel. It is preferable to carry out the polymerization by dropping for a certain period of time. During polymerization, it is added as a chain transfer agent to the monomer mixture to adjust the molecular weight of the polymer. mercaptans, hydrogen, α-methylstyrene dimer, terpenoids, etc. may be added. stomach.

[0043] When polymerization is carried out in the presence of a radical polymerization initiator, an organic peroxide may be used as the radical polymerization initiator. An oxide or an azo compound can be used. Specific examples of organic peroxides include, for example, For example, 2,4-dichlorobenzoyl peroxide, t-butyl peroxypivalate, o-Methylbenzoyl peroxide, bis-3,5,5-trimethylhexanoyl peroxide oxide, octanoyl peroxide, t-butylperoxy-2-ethylhexanoate ester, cyclohexanone peroxide, benzoyl peroxide, methyl ethyl ketone Tomono peroxide, dicumyl peroxide, lauroyl peroxide, diisopropyl Phenylbenzene hydroperoxide, t-butyl hydroperoxide, di-t-butyl Examples include ethyl peroxide.

[0044] Specific examples of azo compounds include 2,2'-azobisisobutyronitrile, 2, 2'-Azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2,4- dimethyl-4-methoxyvaleronitrile) and the like. Among these, benzoyl peroxide and 2,2'-benzoyl peroxide are preferred because of their good polymerizability. Azobisisobutyronitrile, 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-Azobis(2,4-dimethyl-4-methoxyvaleronitrile) is preferred. These radical polymerization initiators can be used alone or in combination of two or more.

[0045] The radical polymerization initiator is useful for controlling the polymerization rate and the molecular weight of the resulting polymer. and the range of 0.0001 to 10 parts by mass relative to 100 parts by mass of the total mass of all monomers. It is preferable to use it in There is no particular limitation on the polymerization temperature, and the polymerization can be carried out at, for example, -100 to 120°C. can.

[0046] [Adhesive composition] The adhesive composition of the present invention contains the polymer. From the viewpoint of achieving both a strong bonding strength after the adhesive composition of the present invention and the adhesive composition of the present invention, The proportion is preferably 20% by mass or more. The adhesive composition of the present invention is advantageous in that it provides a good bonding strength when used as an adhesive layer. The product contains, in addition to the polymer, at least one of the monomers used in the production of the polymer. The proportion of the monomer in the adhesive composition of the present invention is preferably in a range of 100 to 1500 ppm, which is in accordance with the stability of bonding strength. From this viewpoint, the amount is preferably 0.1 to 20 parts by mass relative to 100 parts by mass of the total mass of the polymer of the present invention. It's nice.

[0047] The adhesive composition of the present invention contains, in addition to the polymer and the monomer, a solvent and, if necessary, optional components. The composition may be a mixture of these. The solvent is not particularly limited and can be appropriately selected depending on the purpose. For example, alkanes such as butane, pentane, hexane, heptane, and octane; cyclopentane cycloalkanes such as cyclohexane, cycloheptane, and cyclooctane; methanol , ethanol, propanol, butanol, hexanol, heptanol, octanol Alcohols such as propylene glycol monomethyl ether, propylene glycol monomethyl ether, propylene glycols such as propylene glycol monoethyl ether and propylene glycol monobutyl ether ketones such as acetone, cyclohexanone, and acetophenone; dioxane, tetrahydrofuran Ethers such as propyl ether; esters such as butyl acetate and ethyl 2-hydroxybutyrate halogenated hydrocarbons such as chloroform, methylene chloride, and tetrachloroethane; Aromatic hydrocarbons such as benzene, toluene, and xylene; dimethylformamide, dimethylamine Highly polar solvents such as cetoamide and N-methylpyrrolidone, water (ion-exchanged water, distilled water or purified water) Examples include aqueous solutions containing sodium salts.

[0048] These may be used alone or in combination of two or more. Examples of the optional components include a crosslinking agent, a tackifier, a filler, a stabilizer, and an ultraviolet absorber. silane coupling agents, antistatic agents, etc. The crosslinking agent is a compound that reacts with functional groups, such as hydroxyl groups, contained in the polymer to form a crosslinked structure. There are no particular limitations on the crosslinking agent as long as it forms a structure, and examples thereof include known isocyanate crosslinking agents, Examples of the crosslinking agent include epoxy-based crosslinking agents, aziridine-based crosslinking agents, and metal chelate-based crosslinking agents.

[0049] Examples of the stabilizer include p-methoxyphenol, hydroquinone, and pyrogallol. Examples include catechol, naphthylamine, and tert-methylcatechol. The adhesive composition of the present invention can be produced by a method comprising the steps of: A method of mixing using a commonly used stirrer can be mentioned.

[0050] [Laminate] The laminate of the present invention is a laminate containing the adhesive composition. The laminate of the present invention comprises an adhesive layer made of the adhesive composition of the present invention, a substrate, and and one or more adherends to which the adhesive is to be bonded. The material of the substrate is not particularly limited as long as it can be adhered to the adhesive composition of the present invention. However, for example, polyolefins such as polyethylene, polypropylene, and ethylene-propylene copolymers Polyolefin resins, polyvinyl fluoride, polyvinylidene fluoride, polyethylene fluoride, etc. Fluorinated ethylene resin, polyethylene terephthalate, polybutylene terephthalate, etc. polyester resins, polycarbonate resins, polymethyl methacrylate, etc. Resin, nylon 6, nylon 66, nylon 9, nylon 11, nylon 12, nylon Nylon resins such as Nylon 6T, Nylon 9T, and Nylon 10T, vinyl chloride resins, poly Styrene, styrene-based resins such as ABS, polyphenylene ether-based resins, polyoxymethylene Synthetic resins such as polyethylene resins and polyimide resins, steel, stainless steel, aluminum, These include metals such as magnesium, copper, brass, lead, zinc, and titanium, as well as glass and ceramics. can be.

[0051] In addition, a part of the base material may be modified by various processes. Specific examples of methods include primer treatment by application, corrosion-resistant treatment of metal surfaces, and chemical Etching with chemicals or plasma, plating, optical processing using laser light, etc. Examples of such processes include mechanical processes such as machining, cutting, and polishing. The material of the adherend is not particularly limited as long as it can be adhered to the polymer of the present invention. For example, the materials exemplified above for the substrate can be used, but the bonding strength after the stimulus response is sufficiently high. In this respect, metals such as steel, stainless steel, aluminum, copper, brass, zinc, and titanium are preferred. Either a single metal or an alloy of multiple metals can be used. The side chain of the structure derived from monomer A is decomposed to generate a carboxyl group, which then exhibits its function. The higher the surface free energy of the adherend surface, the more easily the polymerisation occurs after the stimulus response, which is rich in carboxyl groups. High affinity with the body improves the bond strength between the adhesive composition and the adherend by stimuli response. That is, the adherend is made of metals such as steel, stainless steel, aluminum, copper, zinc, etc. However, this is more preferable in that the bonding strength after response to a stimulus is sufficiently high.

[0052] The laminate of the present invention is prepared by dissolving the polymer of the present invention in a solvent or the like and applying the solution to a substrate, and then A method in which the adhesive composition of the present invention is applied to a substrate and then dried and then attached to an adherend. Dry the adhesive and then attach it to the adherend. Then, apply pressure to the adhesive layer and the base material in that order. The method can be prepared by using known methods. The polymer in the present invention is formed by applying a certain amount of physical or chemical energy to the monomers. The substituent (side chain) derived from the ester moiety of Compound A decomposes. .

[0053] The laminate using the polymer of the present invention can be bonded at any timing by utilizing the stimulus responsiveness. In terms of this function, the compound represented by the formula (a) has a function of easily strengthening the strength of the portion. The monomer preferably has a structure in which X in the formula (a) is O, that is, an acetal structure. Desirable. The adhesive strength between the adhesive composition of the present invention and the adherend before the stimulus response is 3.0 N / 25 mm or more. is preferable, 4.0N / 25mm or more is more preferable, and 5.0N / 25mm or more is even more preferable. Furthermore, the adhesive strength between the adhesive composition of the present invention and the adherend before the stimulus response is 20.0 N. / 25mm or less is preferable, 18.0N / 25mm or less is more preferable, 16.0N / 2 The adhesive strength between the adhesive composition of the present invention and the adherend before the response to a stimulus is more preferably 5 mm or less. However, if the strength is 3.0N / 25mm or more, it is easier to maintain the state of adhesion to the adherend. If the bond strength before response is 20.0N / 25mm or less, rework is possible.

[0054] The adhesive strength between the adhesive composition of the present invention and the adherend after the stimulus response is 10.0 N / 25 mm or more. Above is preferable, 15.0N / 25mm or more is more preferable, and 20.0N / 25mm or more is Furthermore, the adhesive strength between the adhesive composition of the present invention and the adherend after the stimulus response is 50 0.0N / 25mm or less is preferable, 45.0N / 25mm or less is more preferable, 40.0 The adhesive strength between the adhesive composition of the present invention and the adherend after the stimulus response is more preferably 25 N / 25 mm or less. If the combined strength is 10.0N / 25mm or more, the laminate will not separate due to impact or vibration during use. If the bond strength after the stimulus response is 50.0N / 25mm or less, The stack can be separated after use.

[0055] When the side chain of the structure derived from the monomer A of the polymer is decomposed, the molecular weight of the polymer decreases. However, since the main chain of the polymer does not shorten, the mass average molecular weight and / or molecular weight of monomer A If the distribution is within a predetermined range, the bonding strength is less likely to decrease. The ester moiety of monomer A decomposes to generate a carboxyl group. The glass transition temperature Tg of the adhesive composition containing the polymer increases, improving the cohesive strength and bonding strength. In addition, when the surface free energy of the adherend surface is high, the adhesive layer and the adherend The interface strength is also improved, and the bonding strength is significantly improved.

[0056] If the degradation of the side chain of the structure derived from the monomer A of the polymer proceeds, it can be used as a stimulus-responsive method. There are no particular limitations on the type of radiation, and examples include active rays such as X-rays, ultraviolet rays, visible light, infrared rays, and microwaves. In addition to physical methods such as irradiating with energy rays, heat, and ultrasound, chemical methods such as contact with hot water and acid are also used. and a method that combines two or more of these methods. Among these, ultraviolet rays, microwaves, heat, ultrasound, and Warm water is preferred, ultraviolet light, heat and warm water are more preferred, and heat and warm water are even more preferred.

[0057] When heat is used as the method, the heating temperature is preferably 100°C or higher, more preferably 120°C or higher. The temperature is preferably 140°C or higher, more preferably 140°C or higher, and most preferably 160°C or higher. In this case, the heating temperature is preferably 250°C or less, more preferably 230°C or less, and more preferably 210°C or less. If the heating temperature is 100°C or higher, If the heating temperature is 250°C or less, thermal deterioration of the adherend will not occur. It becomes more difficult to get.

[0058] When using hot water, the temperature of the hot water is preferably 60°C or higher, and more preferably 70°C or higher. The temperature of the hot water used is preferably 95°C or less, more preferably 90°C or less. If the temperature of the hot water is 60°C or higher, the response time can be shortened. If the following conditions are met, it will be considered safe for the work. For example, the laminate of the present invention may be placed in a constant temperature and humidity chamber or the like to obtain the same effect. The laminate can be easily disassembled by simply placing it on the floor and disposing of it.

[0059] a known photoacid generator is added to the polymer or the adhesive composition in order to enhance stimulus responsiveness; A thermal acid generator or the like may be compounded and used. When an acid is generated by stimulation with light or heat, the compound represented by the formula ( The degradation of the monomer units derived from the monomer represented by a) is promoted, which adjusts the stimuli responsiveness. It is possible. [Example]

[0060] The present invention will be described below with reference to examples, but the present invention is not limited to these examples. There is no. In the following description, "parts" and "%" mean "parts by mass" and "% by mass". [Methods for measuring various physical properties of polymers]

[0061] (1) Molecular weight and molecular weight distribution The mass average molecular weight (Mw) and number average molecular weight (Mn) were determined by gel permeation chromatography ( Measurement was performed using a GPC (Tosoh Corporation, product name: HLC-8420) under the following conditions: did. Column: TSK GUARD COLUMN SUPER HZ-L (DI4. 6mm x 35mm) and two TSK-GEL SUPER HZM-N (DI6.0 mm x 150 mm) connected in series. Eluent:THF Measurement temperature: 40℃ Flow rate: 0.6mL / min Mw and Mn are measured using peak top fractions manufactured by Polymer Laboratories. Four polymethylmethacrylates with molecular weights of 1590, 10290, 55600, and 141500 were used. The value was determined using a calibration curve prepared using acrylate.

[0062] (2) Thermal decomposition temperature Differential thermal and thermogravimetric simultaneous analyzer (manufactured by Hitachi High-Tech Science Corporation, product name: STA73 00), the temperature was increased from 100°C to 450°C at a rate of 10°C / min in a nitrogen atmosphere. The 10% weight loss temperature was measured from the thermogravimetric loss curve observed when the sample was heated.

[0063] [Method for evaluating bond strength] A Tensilon universal testing machine (manufactured by Orientec Co., Ltd., product name: RTC-1250A) was used. The adhesive was peeled off from the three layers of the substrate / bonding layer / adherend at a peeling speed of 300 mm / min in an atmosphere of 23°C. The 180-degree peel strength (N / 25 mm) of each laminate sample was measured, and the following results were obtained: The bonding strength was evaluated according to the evaluation criteria. The laminate sample was prepared by the method described in Example 1 below.

[0064] [Method for evaluating adhesiveness] (Heat treatment) Inert oven (Yamato Scientific Co., Ltd., product name: DN611I) set to 200°C A laminate sample prepared in the same manner as in the evaluation method for the bonding strength was heated in a nitrogen atmosphere. The heating time was 3 minutes from the time the sample was placed in the oven. The sample was carefully removed and air-cooled at room temperature (23°C) overnight. The 180-degree peel strength (N / 25 mm) was measured using the same method as the evaluation method for the bonding strength. It was determined.

[0065] (Moist heat treatment) A thermo-hygrostat (Espec Corporation, product name: PL-2) was set at 70°C and a relative humidity of 95%. J) The laminate sample prepared in the same manner as in the evaluation method for the bonding strength was placed in a humid and hot atmosphere. The treatment time was 3 hours from the time the sample was placed in the thermo-hygrostat. The sample was then carefully removed and air-cooled at room temperature (23°C) overnight. The body sample was subjected to the 180-degree peel strength (N / 25) test using the same method as the bonding strength test described above. mm) was measured.

[0066] (Evaluation criteria) The rate of change in bond strength before and after the stimulus response was calculated according to formula (1), and the following was calculated based on that value. The temporary adhesion was evaluated according to the evaluation criteria. ◎: Change in bonding strength is 160% or more ○: The rate of change in bonding strength is 120% or more but less than 160% ×: The rate of change in bonding strength is less than 120% A = Fa / Fb × 100 ... Equation (1) A: Change in bonding strength (%) Fa: 180° peel strength (N / 25mm) without heat treatment or moist heat treatment Fb: 180-degree peel strength after heat treatment or moist heat treatment (N / 25 mm)

[0067] <Production Example A1> 2-Ethylhexyl vinyl ether 171.9 parts (1.1 mol), hydroquinone 0. 32 parts of benzophenone-3, 0.61 parts of phenothiazine were mixed at room temperature with stirring until uniform. While blowing in 86.1 parts (1.0 mol) of methacrylic acid into the reaction solution, The temperature of the reaction mixture was raised to 80°C after the dropwise addition, while keeping the temperature below 60°C. The reaction mixture was added with 264.5 parts (3.0 mol) of t-butyl methyl ether. ) was added and mixed, and the organic phase was washed once with 135 parts of a 20% by mass aqueous potassium carbonate solution. The collected organic phase was treated with 4-benzoyloxy-2,2,6,6-tetramethylpiperidine-N- 0.07 parts of oxyl was added, and low boiling points were distilled off under reduced pressure using an evaporator. The residue was distilled under reduced pressure to give 1-(2-ethylhexyloxy)ethyl acetate (boiling point 99°C / 400Pa). As a result, 207.0 parts (0.85 mol) of methyl methacrylate (monomer (A1)) was obtained.

[0068] <Manufacturing example A2> Isobutyl vinyl ether 90.1 parts (0.9 mol), hydroquinone 0.14 parts, 0.28 parts of ethenothiazin was added and mixed at room temperature until uniform. Air (10 mL / m While blowing in 51.7 parts (0.6 mol) of methacrylic acid, the reaction mixture was heated to a temperature of 6 The temperature was kept below 0°C during the dropwise addition. After the dropwise addition, the temperature of the reaction mixture was raised to 80°C and the mixture was stirred for 6 hours. To the reaction mixture was added 158.7 parts (1.8 mol) of t-butyl methyl ether. The organic phase was washed once with 200 parts of a 20% by mass aqueous solution of potassium carbonate. Phase 4-benzoyloxy-2,2,6,6-tetramethylpiperidine-N-oxyl 0 0.03 parts of the ethanol was added, and low boiling points were distilled off under reduced pressure using an evaporator. Distillation yielded 1-isobutoxyethyl methacrylate (monomer ( A2) was obtained in an amount of 97.5 parts (0.52 mol).

[0069] Example 1 A four-necked round-bottom flask equipped with a reflux condenser, a stirrer, a nitrogen gas inlet, and a thermometer 70 parts by mass of ethyl acetate, azobisisobutyronitrile (AIBN) as a polymerization initiator 0.04 parts by mass of the monomer (A1) was charged and heated to reflux temperature, and 40 parts by mass of the monomer (A2), n-butyl acetate, and 10 parts by mass of the monomer (A3) were added. A mixed monomer of 60 parts by mass of acrylate and 0.1 parts by mass of 2-hydroxymethacrylate was used. After the dropwise addition, the mixture was heated for 1 hour, and then a toluene solution of 0.09 parts by mass of AIBN was added dropwise. The reaction was carried out at reflux temperature for 2.5 hours, and then diluted with ethyl acetate to give a mass average molecular weight of 3 22,000, molecular weight distribution 3.62, glass transition temperature -43℃ A liquid (solid content 34%) was obtained.

[0070] For 100 parts by mass of the obtained polymer solution, an isocyanate-based crosslinking agent "Coronate L-5 1 part by mass of 5E" was added and stirred at room temperature, and then 50 μm polyethylene terephthalate was added. The film was coated with an applicator so that the thickness after drying was 25 μm. Furthermore, a 38μm polyester release sheet with a light release property is placed over the coated film. After drying at 40°C for 2 minutes, the film was aged at 40°C for 3 days to obtain a bonding film.

[0071] A 0.5mm thick stainless steel (SUS304) plate was used as the adherend, and a light release film was applied. The peeled 25mm x 100mm bonding film was placed in a 23°C atmosphere with a mass of 2 kg. The laminate is made up of three layers: base material, bonding layer, and adherend. A sample was prepared. The laminate sample was left overnight in an atmosphere of 23°C, and then peeled at a rate of 300 mm / min. The bonding strength was evaluated by measuring the 180-degree peel strength (N / 25 mm).

[0072] In addition, a laminate sample prepared in the same manner as the laminate sample was heated at 200°C. After the treatment, the specimen was air-cooled overnight at room temperature (23°C), and then peeled off at a rate of 300 mm / min for 1 minute. The bond strength after the stimulus response was evaluated by measuring the 80-degree peel strength (N / 25 mm). The measurement results are shown in Table 1. The numerical values ​​for each component in the table represent parts by mass.

[0073] [Table 1]

[0074] The abbreviations for each compound in the table are listed below. EHEMA: 1-(2-ethylhexyloxy)ethyl methacrylate (prepared as described above) (The synthetic product synthesized in Example A1). IBEMA: 1-isobutoxyethyl methacrylate (synthesized in the above-mentioned Production Example A2) synthetic products).

[0075] nBA: n-butyl acrylate. 2EHA: 2-ethylhexyl acrylate. MMA: methyl methacrylate. HEMA: 2-hydroxyethyl methacrylate. Coronate L-55E: Adsorbent of tolylene diisocyanate and trimethylolpropane Kutto font, manufactured by Tosoh Corporation.

[0076] <Examples 2 to 6 and Comparative Examples 1 to 4> The same procedure as in Example 1 was carried out except that the monomer composition ratio of the acrylic copolymer was changed according to Table 1. A polymer solution was obtained. Thereafter, a laminate sample was prepared in the same manner as in Example 1. The bond strength and bond strength after stimulus response were evaluated. The evaluation results are shown in Table 1.

[0077] A polymer having a structural unit derived from monomer A and having a thermal weight loss temperature within a predetermined range is used. In Examples 1 to 6, the bonding strength before and after the stimulus response was good. Ta. A polymer that does not have a structural unit derived from monomer A and has a thermal weight loss temperature that exceeds the upper limit specified in this application. In Comparative Examples 1 to 3, the bonding strength after stimulus response was high regardless of the presence or absence of a crosslinking agent or the composition of the main chain. There was little change.

[0078] It has a structural unit derived from monomer A, but its mass average molecular weight is below the lower limit specified in this application. In Comparative Example 4, in which a polymer was used, the bonding strength after the stimulus response was significantly reduced. Example 7 The same procedure as in Example 1 was carried out except that the monomer composition ratio of the acrylic copolymer was changed according to Table 2. A polymer solution was obtained. Thereafter, a laminate sample was prepared in the same manner as in Example 1. .

[0079] The laminate sample was left overnight in an atmosphere of 23°C, and then peeled at a rate of 300 mm / min. The bonding strength was evaluated by measuring the 180-degree peel strength (N / 25 mm). In addition, a laminate sample prepared in the same manner as the above laminate sample was heated at 65°C and 95% Rh. After placing the sample in the adjusted thermo-hygrostat and subjecting it to humid heat treatment for 3 hours, leave it at room temperature (23°C) overnight. After cooling, measure the 180-degree peel strength (N / 25mm) at a peel speed of 300mm / min. The bonding strength after the stimulus response was evaluated by this method. The measurement results are shown in Table 2. The numerical values ​​for each component in the table mean parts by mass.

[0080] [Table 2]

[0081] <Example 8, Comparative Examples 5 and 6> The same as Example 7 except that the monomer composition ratio of the acrylic copolymer and the adherend were changed according to Table 2. A laminate sample was prepared in the same manner, and the bonding strength and the bonding strength after the stimulus response were evaluated. . The evaluation results are shown in Table 2.

[0082] In Examples 7 and 8, a crosslinkable polymer having a structural unit derived from monomer A was used. The bond strength to the adherend was also good both before and after the stimulus response. In addition, in Comparative Examples 5 and 6, in which a crosslinkable polymer not having a structural unit derived from the monomer A was used, In both cases, there was little change in bond strength after the stimulus response. [Industrial Applicability]

[0083] According to the present invention, the adhesive has excellent temporary adhesion, particularly to metal adherends, and the bonding strength can be adjusted by simple processing. It is also possible to provide an adhesive composition containing the polymer. Therefore, the polymer of the present invention is useful in the field of adhesive compositions that require temporary adhesive properties. It can be suitably used in the above-mentioned fields and is therefore extremely important industrially.

Claims

1. A polymer having at least one selected from the group consisting of a structural unit (1) derived from a monomer represented by the following formula (1), a structural unit (2) derived from a monomer represented by the following formula (2), and a structural unit (3) derived from a monomer represented by the following formula (3), and having a weight average molecular weight of 250,000 or more and 2,000,000 or less in terms of polymethyl methacrylate, as measured by gel permeation chromatography: 【Chemistry 1】 (In the formula, X represents an oxygen atom, a sulfur atom, or NR 14 , N represents a nitrogen atom, R 14 represents a hydrogen atom or an alkyl group, Z represents a hydrogen atom or a methyl group, R 1 and R 2 each represent a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, R 3 and R 5 each represent an alkyl group, cycloalkyl group, or aryl group having 1 to 20 carbon atoms, and R 4 and R 6 each represent an alkylene group having 1 to 10 carbon atoms.)

2. 2. The polymer according to claim 1, wherein the 10% thermal weight loss temperature measured by a thermogravimetric and differential thermal analyzer is 140° C. or higher and 300° C. or lower.

3. 3. The polymer according to claim 1, wherein the glass transition temperature measured by differential scanning calorimetry is −50° C. or higher and 0° C. or lower.

4. 4. The polymer according to claim 1, wherein the molecular weight distribution, calculated as polymethyl methacrylate, measured by gel permeation chromatography is 2.5 or more and 8.0 or less.

5. The polymer according to any one of claims 1 to 4, wherein the total proportion of the structural unit (1), the structural unit (2), and the structural unit (3) is 20% by mass or more and 90% by mass or less, relative to all structural units derived from monomers constituting the polymer.

6. An adhesive composition comprising the polymer according to any one of claims 1 to 5.

7. A laminate comprising a layer comprising the adhesive composition of claim 6 and at least one metal layer in contact with said layer.

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