Polymer and adhesive composition containing said polymer

Abstract

To provide a polymer that is excellent in joint strength and decomposability, and allows easy adjustment of the joint strength, and an adhesive composition containing the polymer.SOLUTION: A polymer has a constitutional unit derived from a monomer A having a specific constitution, which has the structure of oxygen atom-carbon atom-X, where X is an oxygen atom, a sulfur atom or a nitrogen atom. The polymer has a glass transition temperature of -45°C or higher and 30°C or lower as measured by differential calorimetric analysis.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a polymer that is stimuli-responsive, has excellent dismantling properties, and has easy-to-adjust bonding strength, and The present invention relates to an adhesive composition containing the 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. The easy-to-disassemble technology that can peel off the parts is beneficial from the perspective of reducing the labor required in the manufacturing process and separating and reusing composites. The spread of this technology is expected. Patent Document 1 describes a method for manufacturing a polyacetal resin having a hemiacetal skeleton as a main chain structure as an adhesive. The main chain structure consisting of a hemiacetal skeleton is hydrolyzed with an acid or the like. By disassembling the joint, the joint strength can be reduced at any time, making it possible to achieve easy-to-disassemble joints. It is conceivable that the composition may be used as a coating composition.

[0003] However, the polymer described in Patent Document 1 is a vinyl ether compound produced by cationic polymerization. Because it uses an alternating copolymer of a compound and an aldehyde compound, the molecular weight is uniformly low and the bonding strength is In addition, it was difficult to adjust the chemical composition by copolymerizing a third component to improve heat resistance and bonding strength. It was also difficult to adjust from Non-Patent Document 1 discloses a method for producing a polymer using a (meth)acrylate having a hemiacetal skeleton as a substituent. The acrylic resin described in Non-Patent Document 1 has thermal decomposition properties. It is also clearly stated that the thermal decomposition property is due to the hemiacetal skeleton.

[0004] However, in the case of applying a thermally decomposable acrylic resin to bonding described in Non-Patent Document 1, There is no mention of the ease of disassembly, and there is no mention or suggestion of the ease of disassembly. It was unclear whether it could be used as a coating composition. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-211254 [Non-patent literature]

[0006] [Non-Patent Document 1] Reactive & Functional Polymers,46(2001),293-298. Summary of the Invention [Problem to be solved by the invention]

[0007] An object of the present invention is to provide a polymer that is excellent in bonding strength and ease of dismantling. Another object of the present invention is to provide an adhesive composition containing the polymer. [Means for solving the problem]

[0008] That is, the present invention is summarized as follows [1] to

[10] . [1] A polymer having a structural unit derived from a monomer A having a structure represented by the following formula (a): Therefore, the glass transition temperature measured by differential calorimetry is -45°C or higher and 30°C or lower. Merge.

[0009] [ka]

[0010] (In the formula (a), O represents an oxygen atom, C represents a carbon atom, and X represents an oxygen atom, a sulfur atom, or N (R 14 ), N is a nitrogen atom, R 14 represents a hydrogen atom or an alkyl group. [2] The mass average molecular weight in PMMA equivalent is 110,000 or more and 450,000 or less, The polymer according to [1]. [3] The formula (a) is the following formula (1), the following formula (2), or the following formula (3): [1] or The polymer according to [2].

[0011] [ka]

[0012] (wherein X is an oxygen atom, a sulfur atom, or N(R 14 ), N represents a nitrogen atom, and R 14 represents a hydrogen atom or an alkyl group, and R 1 and R 2 are each a hydrogen atom or a group having 1 to 1 carbon atoms 0 alkyl group, and R 3 and R 5 are alkyl groups having 1 to 20 carbon atoms, and cycloalkyl groups. represents an alkyl group or an aryl group, and R 4 and R 6 are alkylene groups with 1 to 10 carbon atoms. It indicates a hydroxyl group.)

[0013] [4] The structure represented by formula (a) of the monomer A is located in a side chain of the polymer. The polymer according to any one of [1] to [3]. [5] The polymer according to any one of [1] to [4], wherein the monomer A is a methacrylate. Merge. [6] The glass transition temperature measured by differential calorimetry is -40°C or higher and 0°C or lower. [1 [5] The polymer according to any one of [1] to [5].

[0014] [7] The quality of the constituent units derived from the monomer A with respect to all the constituent units derived from the monomers constituting the polymer. The polymer according to any one of [1] to [6], wherein the amount ratio is 25% or more and 65% or less. [8] The molecular weight distribution measured by gel permeation chromatography is 2.0 or more and 7.0 or less. The polymer according to any one of [1] to [7]. [9] An adhesive composition comprising the polymer according to any one of [1] to [8].

[10] A laminate comprising the adhesive composition according to [9]. [Effects of the Invention]

[0015] According to the present invention, it is possible to provide a polymer that is excellent in ease of dismantling and in which the bonding strength can be easily adjusted. It is also possible to provide an adhesive composition containing the polymer. DETAILED DESCRIPTION OF THE INVENTION

[0016] 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.

[0017] [Polymer] The polymer of the present invention has a structural unit derived from a monomer A having a structure represented by the following formula (a): The glass transition temperature measured by differential scanning calorimetry is -45°C or higher and 30°C or lower.

[0018] [ka]

[0019] (In the formula (a), O represents an oxygen atom, C represents a carbon atom, and X represents an oxygen atom, a sulfur atom, or N (R 14 ), N is a nitrogen atom, R 14 represents a hydrogen atom or an alkyl group. In terms of ease of disassembly, the formula (a) is the following formula (1), the following formula (2), or the following formula (3): It is preferable that

[0020] [ka]

[0021] (wherein X is an oxygen atom, a sulfur atom, or N(R 14 ) where N represents a nitrogen atom and R 14 teeth represents a hydrogen atom or an alkyl group, and R 1 and R 2 are each a hydrogen atom or a group having 1 to 10 carbon atoms represents an alkyl group of the formula R 3 and R 5 are alkyl groups with 1 to 20 carbon atoms, cycloalkyl groups, and R represents an alkyl group or an aryl group; 4 and R 6 are alkylenes with 1 to 10 carbon atoms. )

[0022] 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, an oxygen atom is preferred in terms of ease of decomposition. That is, it is preferable to have an acetal structure in which X in formula (a) is O.

[0023] In formula (1), R 1 and R 2 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. 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.

[0024] R 1 and R 2 The number of carbon atoms in the alkyl group is preferably 1 to 4 from the viewpoint of ease of decomposition, and more preferably 1 to 4. 3 is more preferred, and 1 or 2 is even more preferred. 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, the combination of a hydrogen atom and a methyl group is preferred in terms of ease of decomposition. The combination is preferred.

[0025] 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 groups listed above include decyl, dodecyl, and tetradecyl groups. In terms of somatic properties, R 3 The alkyl group preferably has 1 to 10 carbon atoms. In terms of ease of disassembly, the cycloalkyl group is preferably a cycloalkyl group having 4 to 8 carbon atoms. A cyclohexyl group, a cyclopentyl group, etc. are more preferred.

[0026] In terms of ease of dismantling, the aryl group is preferably an aryl group having 6 to 20 carbon atoms, A phenyl group, a naphthyl group, etc. are more preferred. In terms of ease of disassembly, R 3 As the alkyl group, alkyl groups and cycloalkyl groups having 1 to 10 carbon atoms are preferred. Desirable. 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.

[0027] 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.

[0028] In terms of ease of disassembly, R 4 The alkylene group preferably has 2 to 7 carbon atoms, and more preferably has 3 or 4 carbon atoms. More preferable. 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.

[0029] 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 ease of disassembly, the same substituents as those shown in The aspect is also the same.

[0030] In the polymer of the present invention having a structural unit derived from the monomer A, the monomer A has the formula ( The structure represented by a) is preferably located on the side chain of the polymer. As the monomer A, the (a) is a structure represented by the formula (1), (2) or (3) (hereinafter (hereinafter referred to as "structure (i)") and an ethylenically unsaturated bond (polymerizable carbon-carbon double bond). In this case, the structural unit derived from the monomer A is a monomer having the structure That is, the structure (i) has a structure in which the ethylenically unsaturated bond is cleaved to form a single bond. is located on a side chain (substituent of the main chain) relative to the main chain of the polymer.

[0031] The polymer of the present invention is easily dissolved in an organic solvent, and the processability in the step of obtaining a laminate described below is improved. To improve the properties, the monomer A is a monofunctional monomer having one ethylenically unsaturated bond. It is preferable that Examples of the monomer A include a monomer represented by the following formula (A-1), a monomer represented by the following formula (A-2), and a monomer represented by the following formula (A-3).

[0032] [ka]

[0033] (Wherein, Z is CH2=CH-COO-, CH2=C(CH3)-COO-, CH(CH 3) =CH-COO-, CHR X =CH-COO-, CH2=C(CH2R X )-COO - or CH2=CR X -CH2COO-, R X is the structure (i) or alkylene represents an ester group, and X is -O-, -S-, or -NR 14 - indicates R 14 is a hydrogen atom or R represents an alkyl group. 1 ~R 6 has the same meaning as above.) In Z, CH2=CH-COO- is an acryloyloxy group, CH2=C(CH3) -COO- is a methacryloyloxy group.

[0034] CH(CH3)=CH-COO- is a crotonoyloxy group (an ethylenically unsaturated bond) trans-form) or isocrotonoyloxy group (ethylenically unsaturated bond is cis-form). CHR X =CH-COO- is a hemiacetal ester group in which the carboxyl group is a hemiacetal ester group, Maleinoyloxy group (ethylenically unsaturated fatty acid ester group or alkyl ester group) substituted with unsaturated bond is cis-type) or fumaroyloxy group (ethylenically unsaturated bond is trans-type) be.

[0035] R in the structure (i) X is R in Eq. (1). 3 The same substituents as those shown in The same applies to the embodiment. In terms of ease of disassembly, R in the structure (i) X is a group to which Z is bonded. It is preferable that the monomer A has the same structure as the group of the compound represented by formula (A-1). In this case, in terms of ease of disassembly, R X -CR 1 R 2 -XR 3 It is preferable that the group is represented by stomach.

[0036] R X The alkyl ester group in X1 It is shown by R X1 is an alkyl group In terms of ease of disassembly, R X1 The alkyl group is preferably an alkyl group having 1 to 6 carbon atoms. A methyl group is more preferred. The above CH2=C(CH2R X )-COO- or CH2=CR X -CH2COO- is The carboxy group is a hemiacetal ester group, a hemiketal ester group, or an alkyl ester group. R is an itaconoyloxy group substituted with an aryl group. X is R in equation (1). 3 The same substituent as The preferred embodiments are also the same.

[0037] From the viewpoint of ease of disassembly, Z is preferably CH2=C(CH3)-COO-. The polymer of the present invention exhibits easy disassembly by decomposing the structure (i) derived from the monomer A. If Z is CH2=C(CH3)-COO-, when the structure (i) is decomposed, the polymer The increase in the glass transition temperature Tg of the adhesive composition containing the polymer of the present invention becomes large, and the adhesive composition containing the polymer of the present invention becomes large. It is easy to reduce strength.

[0038] Generally, the glass transition temperature Tg of a polymer is determined by the glass transition temperature of the homopolymer of the constituent monomers. It can be estimated from the degree of polymerization and the mass ratio of the monomer (Fox's formula). If Z is CH2=C(CH3)-COO-, then when the structure (i) is decomposed, The structure changes to that derived from acrylic acid (CH2=C(CH3)-COOH). On the other hand, when Z is C If H2=CH-COO-, when the structure (i) is decomposed, acrylic acid (CH2= CH-COOH)-derived structure.

[0039] 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 is 106°C (both are from "Polymer Handbook 4th The glass transition of the polymer after the decomposition of the structure (i) is The transition temperature Tg increases significantly when Z is CH2=C(CH3)-COO-. , which tends to reduce the bonding strength of the adhesive composition.

[0040] The monomer A is preferably a (meth)acrylate, and examples thereof include the following compounds: It can be obtained.

[0041] [ka]

[0042] The monomer A may be a commercially available product or may be appropriately synthesized using a known method. A compound 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, cyclohexyl (meth)acrylate, phenyl (meth)acrylate, benzo Dimethyl (meth)acrylate, Isobornyl (meth)acrylate, 2-Methoxyethyl ( meth)acrylate, 2-ethoxyethyl (meth)acrylate, phenoxyethyl (meth)acrylate (meth)acrylates such as methacrylate;

[0043] 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;

[0044] 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;

[0045] 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.

[0046] 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 compactness, (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 , i-propyl (meth)acrylate, n-butyl (meth)acrylate, i-butyl (Meth)acrylate, t-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate Acrylate and 2-hydroxyethyl (meth)acrylate are more preferable, and bonding strength is These acrylates are more preferred in that they are easy to fill.

[0047] The glass transition temperature of the polymer of the present invention is −45° C. or higher, preferably −40° C. or higher. The glass transition temperature of the polymer of the present invention is 30°C or lower, preferably 15°C or lower, A temperature of 0°C or lower is more preferable. If the glass transition temperature of the polymer of the present invention is -45°C or higher, the polymer can be handled at room temperature. When the glass transition temperature of the polymer of the present invention is 30° C. or less, the polymer can be easily handled during polymerization. When an adhesive composition containing the polymer is prepared, the adhesive strength is excellent.

[0048] The glass transition temperature can also be measured, for example, by differential scanning calorimetry (DSC). The glass transition temperature of the polymer of the present invention varies depending on the types and composition ratio of the monomers constituting the polymer. can be adjusted. The mass average molecular weight (Mw) of the polymer of the present invention is preferably 110,000 or more, and more preferably 130 More preferably, the molecular weight is 1,000 or more, and even more preferably, 150,000 or more. The mass average molecular weight of the polymer is preferably 450,000 or less, more preferably 400,000 or less. It is preferable that the molecular weight is 350,000 or less.

[0049] When the weight average molecular weight of the polymer of the present invention is 110,000 or more, the adhesive composition containing the polymer The polymer of the present invention has a mass average molecular weight of 450,000 and has excellent bonding strength when formed into a composition. If the thickness is less than or equal to the above, the ease of dismantling in response to a stimulus is excellent. The molecular weight distribution (Mw / Mn) of the polymer of the present invention is preferably 2.0 or more, and more preferably 2.2 or more. The molecular weight distribution of the polymer of the present invention is more preferably 7.0 or more, and even more preferably 2.3 or more. Preferably, it is 5.0 or less, more preferably 5.0 or less, and even more preferably 3.0 or less.

[0050] If the molecular weight distribution of the polymer of the present invention is 2.0 or more, it is considered to be an adhesive composition containing the polymer. When the molecular weight distribution of the polymer of the present invention is 7.0 or less, the bonding strength is excellent in response to stimuli. This makes it easy to disassemble. 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. Measurement was performed by gel permeation chromatography (GPC) using polymethyl methacrylate (PMMA) as the standard substance. It is possible to do this.

[0051] 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 this amount is preferably 25% by mass or more, more preferably 30% by mass or more, and more preferably 35% 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 65% ​​by mass or less, more preferably 60% by mass or less. It is preferably 55 mass % or less, and more preferably 55 mass % or less.

[0052] When the proportion of the structural units derived from the monomer A in the polymer of the present invention is 25% by mass or more, The proportion of the structural units derived from A in the polymer of the present invention is If the proportion is 65% by mass or less, the adhesive composition containing the polymer will have excellent bonding strength. Furthermore, the polymer of the present invention allows for easy adjustment of the bonding strength.

[0053] [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.

[0054] 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. In aqueous polymerization such as suspension polymerization and emulsion polymerization, it is easy to control the heat generated by polymerization. However, suspension polymerization is preferred because it allows for simpler recovery of the final product and provides higher productivity. In the method for producing a polymer of the present invention, the polymerization rate is high because all the monomers are reacted at the start of the reaction. It is preferable that all of the components are already placed in the same reaction vessel.

[0055] During polymerization, mercaptans are used as chain transfer agents to adjust the molecular weight of the polymer. , hydrogen, α-methylstyrene dimer, terpenoids, etc. may also be added. 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.

[0056] Specific examples of azo compounds include 2,2'-azobisisobutyronitrile, 2, 2'-Azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2,4 -dimethyl-4-methoxyvaleronitrile). Among these, benzoyl peroxide and 2,2'-azoline 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.

[0057] 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 250°C. can.

[0058] [Adhesive composition] The adhesive composition of the present invention contains the above polymer. The proportion of the polymer in the total 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.

[0059] 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.

[0060] 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 can form a structure. For example, known isocyanate crosslinking agents, Examples of the crosslinking agent include epoxy-based crosslinking agents, aziridine-based crosslinking agents, and metal chelate-based crosslinking agents.

[0061] 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.

[0062] [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 Examples of the material include synthetic resins such as polyethylene resins and polyimide resins, metals, glass, and ceramics. do.

[0063] 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 base material can be used, but synthetic resins are preferred in terms of ease of disassembly. The polymer of the present invention is preferably a polymer represented by the above formula (a) which is contained in a structural unit derived from the monomer A. The structure, particularly the structure (i), is decomposed to exhibit easy dismantling properties. When the structure formed upon decomposition has low affinity with the adherend, the adhesive containing the polymer of the present invention is The bonding strength of the adhesive composition is likely to decrease, and the adhesive composition is likely to exhibit easy dismantling.

[0064] 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 of the present invention contains a structural unit derived from the monomer A represented by the formula (a). The structure is preferably located on the side chain of the polymer. By applying a certain amount of energy to the In other words, it has stimulus-responsiveness.

[0065] The laminate using the polymer of the present invention can be bonded at any timing by utilizing the stimulus responsiveness. In terms of ease of disassembly, the part represented by the formula (a) is easily disassembled. The structure is preferably a structure in which X in the formula (a) is O, that is, an acetal structure. Desirable. When the structure represented by the formula (a) in the side chain is decomposed, the molecular weight of the polymer decreases, but the weight Since the main chain of the bonded polymer does not shorten, the bond strength is unlikely to decrease. In particular, the polymer of the present invention has a high bonding strength due to the decomposition of the structure represented by the formula (a) in the side chain. Although the detailed mechanism has not yet been clarified, it is believed that the polymer In this case, rapid foaming from the polymer occurs in the temperature range where the structure represented by the formula (a) of the side chain decomposes. The expansion was observed, which suggests that one of the causes was the formation of voids in the adhesive layer due to decomposition gas. It is presumed that the bonding strength was significantly reduced due to the side chain represented by the formula (a). The decomposition of the structure increases the glass transition temperature (Tg) of the polymer, resulting in the formation of adhesives containing the polymer. It is presumed that a decrease in the bonding strength of the adhesive composition also contributed to this.

[0066] If the decomposition of the structure represented by the formula (a) of the side chain proceeds, it is particularly useful as a stimulus-responsive method. There is no limitation, and examples of the active energy include X-rays, ultraviolet rays, visible light, infrared rays, and microwaves. Physical methods include irradiating with rays, heat, ultrasound, etc., as well as chemical methods such as contacting with hot water or acid. and a method of using two or more of them in combination. 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.

[0067] When heat is used as the method, the heating temperature is preferably 80°C or higher, more preferably 100°C or higher. The temperature is preferably 120°C or higher, more preferably 140°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 80°C or higher, it is easy to understand. If the heating temperature is 250°C or less, thermal degradation of the adherend is unlikely to occur. do.

[0068] 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.

[0069] 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 blended and used. When an acid is generated by stimulation with light or heat, the above structure Since the decomposition of (i) is promoted, stimulus responsiveness can be adjusted. [Example]

[0070] 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".

[0071] [Methods for measuring various physical properties of polymers] (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.

[0072] (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.

[0073] (3) Glass transition temperature Differential scanning calorimetry device (Hitachi High-Tech Science Corporation, product name: DSC6200) The observed temperature was raised from -70°C to 120°C at a rate of 10°C / min under a nitrogen atmosphere. The extrapolated glass transition onset temperature was determined from the DSC curve.

[0074] [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 the laminate sample was measured. The bonding strength was evaluated according to the following evaluation criteria. The laminate sample was prepared by the method described in Example 1 below.

[0075] (Evaluation criteria) Good: 180 degree peel strength is 8.0N / 25mm or more, and the bonding strength is excellent. ×: The 180-degree peel strength was less than 8.0 N / 25 mm, and the bonding strength was poor. NG: The bond strength could not be evaluated because the bond was not formed.

[0076] [Evaluation method for ease of disassembly] (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. By determining the degree of ease of dismantling, the ease of dismantling was evaluated according to the following evaluation criteria.

[0077] (Moist heat treatment) A thermo-hygrostat (manufactured by Espec Corporation, product name: PL- 2J), a 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 24 hours from the time the sample was placed in the thermo-hygrostat. The sample was carefully removed and then air-cooled at room temperature (23°C) overnight. The laminate samples were subjected to the 180-degree peel strength (N / 25mm) and evaluated the ease of dismantling according to the following criteria.

[0078] (Evaluation criteria) Good: 180 degree peel strength is less than 6.5N / 25mm, and it is easy to dismantle. ×: 180 degree peel strength is 6.5N / 25mm or more, and ease of dismantling is poor. NG: Because the parts were not joined, ease of disassembly could not be evaluated.

[0079] <Production Example A1> 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 ( A1) was obtained in an amount of 97.5 parts (0.52 mol).

[0080] <Manufacturing example A2> Butyl vinyl ether 150.2 parts (1.5 mol), hydroquinone 0.24 parts, phenyl 0.47 parts of thiazin were mixed at room temperature with stirring until uniform. n) was blown into the reaction mixture, and 86.1 parts (1.0 mol) of methacrylic acid was added. After the addition, the temperature of the reaction mixture was raised to 80°C and the mixture was allowed to react for 5 hours. 264.5 parts (3.0 mol) of t-butyl methyl ether was added to the reaction mixture and mixed. The organic phase was washed once with 350 parts of a 20% by mass aqueous solution of potassium carbonate. 4-Benzoyloxy-2,2,6,6-tetramethylpiperidine-N-oxyl 0. The resulting residue was distilled under reduced pressure using an evaporator to remove low boiling points. Distillation yielded 1-butoxyethyl methacrylate (monomer (A2)) with a boiling point of 70°C / 667 Pa. ) 166.9 parts (0.91 mol) was obtained.

[0081] <Manufacturing example A3> 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 (A3)) was obtained.

[0082] Example 1 Monomer (A1) 50 parts by mass, n-butyl acrylate 25 parts by mass, 2-ethylhexyl 25 parts by weight of 2,2'-azobisisobutyronide in 100 parts by weight of toluene The reaction was carried out at 80°C for 5 hours using 0.003 parts by mass of tolyl as an initiator, and the resulting mixture was added to tetrahydrofuran. The mass average molecular weight was 308,000, the molecular weight distribution was 2.50, and the glass transition temperature was -19 A solution of acrylic copolymer (solid content 20%) at ° C. was obtained.

[0083] The obtained polymer solution was dried on a 50 μm polyethylene terephthalate (PET) film. Apply with an applicator so that the thickness after drying is 125 μm, and dry overnight at 23°C. Thus, a bonding film was obtained. A 188 μm thick PET film was used as the adherend, and a 25 mm x 100 mm bonding The film was pressed with a hand press at a pressure of 5 MPa for 5 minutes in an atmosphere of 23°C. A laminate sample consisting of three layers: a bonding layer and an adherend was prepared.

[0084] 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 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 ease of dismantling 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.

[0085] [Table 1]

[0086] The abbreviations for each compound in the table are listed below. Monomer (A1): 1-isobutoxyethyl methacrylate (synthesized in the above-mentioned Production Example A1) synthetic products). Monomer (A2): 1-butoxyethyl methacrylate (synthesized in the above-mentioned Production Example A2) synthetic products).

[0087] Monomer (A3): 1-(2-ethylhexyloxy)ethyl methacrylate (as described above) (Synthetic product synthesized in Production Example A3). nBA: n-butyl acrylate. 2EHA: 2-ethylhexyl acrylate. MMA: methyl methacrylate.

[0088] HEMA: 2-hydroxyethyl methacrylate. AIBN: 2,2'-azobisisobutyronitrile. Coronate L-55E: Adsorbent of tolylene diisocyanate and trimethylolpropane Kutto font, manufactured by Tosoh Corporation. <Examples 2 to 7 and Comparative Examples 1 to 5> 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 ease of disassembly were evaluated.

[0089] The evaluation results are shown in Table 1. A polymer having a structural unit derived from monomer A and having a glass transition temperature in a predetermined range is used. Examples 1 to 7 in which the adhesive was used had good bonding strength and ease of disassembly. Comparative Examples 1 and 2, which were outside the specified range and used polymers that did not have a structural unit derived from monomer A, The bonding strength was poor. Comparative Example 3, which used a polymer not having a structural unit derived from monomer A, Although the glass transition temperature was within the range specified in this application, the bonding strength was poor. In Comparative Example 4, a polymer having a unit and a glass transition temperature outside the upper limit specified in the present application was used. Since no bonding occurred, it was not possible to evaluate the bonding strength and ease of disassembly. In Comparative Example 5, a polymer having a glass transition temperature outside the lower limit of the specification of the present invention was used. The strength was poor.

[0090] Example 8 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 (A3) was charged and heated to reflux temperature, and 40 parts by mass of the monomer (A4) and n-butyl acetate 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 0.09 parts by mass of AIBN in toluene 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 3.60, glass transition temperature -43℃ A liquid (solid content 34%) was obtained.

[0091] 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 coating was applied to a polyethylene terephthalate (PET) film with an applicator so that the thickness after drying was 25 μm. Furthermore, a 38μm polyester release sheet with easy peeling properties was 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.

[0092] A 188 μm thick PET film was used as the adherend, and the light release film was peeled off. The bonding film, measuring 100 mm x 100 mm, was rolled with a 2 kg rubber roller in an atmosphere of 23°C. The sample was pressed and attached twice, creating a laminated sample consisting of three layers: base material, bonding layer, and adherend. Ta. 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).

[0093] 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 ease of dismantling was evaluated by measuring the 80-degree peel strength (N / 25 mm). The measurement results are shown in Table 2. The numerical values ​​for each component in the table mean parts by mass.

[0094] [Table 2]

[0095] <Comparative Example 6> The same procedure as in Example 8 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 8. The bond strength and ease of disassembly were evaluated. The evaluation results are shown in Table 2. A crosslinkable polymer having a structural unit derived from monomer A and having a glass transition temperature within a predetermined range. In Example 8, which used the combined product, the bonding strength and ease of disassembly were good. In Comparative Example 6, which used a crosslinkable polymer not having the structural unit, the ease of dismantling was low. Ta.

[0096] Example 9 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 3. A polymer solution was obtained. Thereafter, a laminate sample was prepared in the same manner as in Example 1. The bonding strength and ease of disassembly were evaluated in the same manner as in Example 1, except that the wet heat evaluation was used to evaluate ease of disassembly. It was worth it. The evaluation results are shown in Table 3.

[0097] [Table 3]

[0098] <Example 10, Comparative Example 7> The same procedure as in Example 9 was carried out except that the monomer composition ratio of the acrylic copolymer was changed according to Table 3. A polymer solution was obtained. Thereafter, a laminate sample was prepared in the same manner as in Example 9. The bonding strength and ease of disassembly were evaluated in the same manner as in Example 9. The evaluation results are shown in Table 3.

[0099] A polymer having a structural unit derived from monomer A and having a glass transition temperature in a predetermined range is used. Examples 9 and 10, which used the monomer A, had good bonding strength and ease of disassembly. In Comparative Example 7, in which a polymer having no structural unit was used, the glass transition temperature was within the range specified in the present application. However, the bonding strength was poor. [Industrial Applicability]

[0100] According to the present invention, a polymer excellent in bonding strength and ease of dismantling is provided, and the bonding strength can be easily adjusted. It is also possible to provide an adhesive composition containing the polymer. Therefore, the polymer of the present invention can be suitably used in the field of adhesive compositions that require easy dismantling. , which is extremely important industrially.

Claims

1. A polymer having a structural unit derived from a monomer A which is a methacrylate having a structure (i) represented by the following formula (1), the following formula (2), or the following formula (3), wherein the glass transition temperature measured by differential scanning calorimetry is -45°C or higher and -17°C or lower. 【Chemistry 1】 (In the formula, X represents an oxygen atom, a sulfur atom, or N(R 14 ), N represents a nitrogen atom, R 14 represents a hydrogen atom or an alkyl 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. The polymer according to claim 1, having a weight average molecular weight in terms of PMMA of 110,000 or more and 450,000 or less.

3. A polymer described in claim 1 or 2, wherein the glass transition temperature is -40°C or higher and -17°C or lower.

4. The polymer according to any one of claims 1 to 3, wherein the mass ratio of the structural units derived from the monomer A to the structural units derived from all monomers constituting the polymer is 25% or more and 65% or less.

5. 5. The polymer according to claim 1, wherein the molecular weight distribution measured by gel permeation chromatography is 2.0 or more and 7.0 or less.

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

7. A laminate comprising the adhesive composition of claim 6.

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