Elastic adhesive composition

Abstract

The present invention aims to provide an adhesive composition that possesses the properties of crosslinked rubber, is detachable and recombinable, and has good workability. [Solution] The present invention provides an elastic adhesive composition containing a bond-exchange type dynamic covalent bond-containing rubber polymer, comprising: (I): a carboxyl group-modified rubber polymer (A) which is a carboxyl group-modified isoprene polymer (A1) and / or a carboxyl group-modified silicone polymer (A2); and (II): a compound (B) having two or more epoxy groups, wherein the connecting portion of the constituent units (I) and (II) includes a covalent bond formed by bond exchange between the carboxyl groups of the polymer (A) and the epoxy groups of the compound (B).

Description

Technical Field

[0001] The present disclosure relates to an elastic adhesive composition, and more particularly, to an elastic adhesive composition containing a bond-exchangeable dynamic covalent bond-containing rubber polymer and a method for producing the same.

Background Art

[0002] Crosslinked rubber has a three-dimensional network structure in which polymer chains are linked, and is used as an adhesive having moisture barrier properties.

[0003] For example, Patent Document 1 describes an adhesive composition containing an isoprene rubber having a hydroxyl group, an isobutylene-based polymer, and a crosslinking agent, which has an excellent balance between adhesive strength and holding power.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The network structure of the crosslinked rubber described in Patent Document 1 is formed by strong covalent bonds, and the crosslinking points are irreversible, while it does not have self-healing properties. Therefore, once adhered, it is difficult to disassemble, and recycling and reuse are difficult. In addition, general coating-type adhesives have a problem that the viscosity decreases when applied to a substrate and heated. For example, when a lid is placed on the portion where the adhesive is applied when adhering a lid to a container, dripping is likely to occur, and the workability is poor. [

[0006] In view of such a situation, the present disclosure has been made, and an object thereof is to provide an adhesive composition that has the characteristics of crosslinked rubber, can be detached and reformed, and has good workability.

[0007] The present invention provides the following [1] to

[11] . [1] Constituent unit (I): A constituent unit derived from a carboxyl group-modified rubber polymer (A), which is a carboxyl group-modified isoprene polymer (A1) and / or a carboxyl group-modified silicone polymer (A2), Constituent unit (II): A constituent unit derived from compound (B) having two or more epoxy groups Includes, The connecting portion of the constituent units (I) and (II) includes a covalent bond formed by the exchange of bonds between the carboxyl group of the polymer (A) and the epoxy group of the compound (B). An elastic adhesive composition containing a bond-exchange type dynamic covalent bond-containing rubber polymer. [2] The composition according to [1], wherein the mass-average molecular weight of the isoprene polymer (A1) is 5,000 to 1,000,000. [3] The composition according to [1], wherein the number average molecular weight of the silicone polymer (A2) is 700 to 40,000. [4] The composition according to any one of [1] to [3], wherein the carboxyl group equivalent of the carboxyl group-modified rubber polymer (A) is 150 to 40,000 g / mol. [5] The composition according to any one of [1] to [4], wherein the compound (B) comprises one or more compounds (B1) selected from epoxy group-modified silicone oil, 1,4-butanediol diglycidyl ether, 1,2,7,8-diepoxyoctane, and neopentyl glycol diglycidyl ether. [6] The composition according to any one of [1] to [4], wherein the compound (B) further comprises a compound (B2) having a tertiary amine structure. [7] The composition according to [6], wherein the compound (B2) comprises one or more compounds selected from 4,4'-methylenebis(N,N-diglycidylaniline), N,N'-[1,3-phenylenebis(methylene)]bis[bis(oxiran-2-ylmethyl)amine], 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, and N-[2-methyl-4-(oxiranylmethoxy)phenyl]-N-(oxiranylmethoxy)oxiranimethaneamine). [8] The composition according to any one of [1] to [7], wherein the bond-exchange type dynamic covalent bond-containing rubber polymer is a polymer obtained by crosslinking the polymer (A) and the compound (B) with a transesterification catalyst (C). [9] The composition according to [8], wherein the catalyst (C) comprises one or more selected from zinc acetate, zinc acetylacetone(II) salt, triphenylphosphine, and 1,5,7-triazabicyclo[4.4.0]deca-5-ene.

[10] The composition according to any one of [1] to [9], wherein the polymer (A) at the time of crosslinking is in liquid form.

[11] A composition according to any one of [1] to

[10] , which is an elastic adhesive for vehicles. [Effects of the Invention]

[0008] The elastic adhesive composition of the present invention contains a rubber polymer having bond-exchange type dynamic covalent bonds, allowing for the dissociation and recombination of these bonds, and possessing the elasticity characteristic of rubber. As a result, it exhibits excellent adhesion and disassembly properties as an adhesive. Furthermore, since it can be re-adhered and re-disassembled after disassembly, it is easy to reuse and recycle, making it a useful adhesive that considers the environment. [Modes for carrying out the invention]

[0009] In this specification, when "X~Y" (where X and Y are any numbers) is written, unless otherwise specified, it means "X or greater and Y or less," and also includes the meanings of "preferably greater than X" or "preferably less than Y."

[0010] In this specification, unless otherwise specified, the upper or lower limits of numerical ranges described in stages may be arbitrarily combined with the upper or lower limits of numerical ranges in other stages. Furthermore, in numerical ranges described in this specification, the upper or lower limits of those ranges may be replaced with the values ​​shown in the examples.

[0011] In this specification, "X and / or Y (where X and Y are any combination)" means at least one of X and Y, and can mean X only, Y only, or X and Y, unless otherwise specified.

[0012] [1. Bond exchange type dynamic covalent bond-containing rubber polymer] The adhesive composition of the present invention contains a bond-exchange type dynamic covalent bond-containing rubber polymer. The bond-exchange type dynamic covalent bond-containing rubber polymer is a polymer containing constituent units (I) and (II). Constituent units (I) and (II) are constituent units derived from the following raw materials, respectively.

[0013] [1.1 (A) Carboxylate-modified rubber polymer] The constituent unit (I) is a constituent unit derived from the carboxyl group-modified rubber polymer (A) (hereinafter sometimes simply referred to as rubber polymer (A)). In this specification, the carboxyl group-modified rubber polymer is an unvulcanized rubber polymer having carboxyl groups.

[0014] -Carboxyl group- Examples of carboxyl groups include -COOH, -COO-, and -COOR (where R is a metal atom or an ammonium group), and any of these may be used. The carboxyl group content of the rubber polymer (A) is preferably 0.05 to 5% by mass, more preferably 0.1 to 3% by mass, and even more preferably 0.5 to 2% by mass, relative to the mass of polymer (A). The position of the carboxyl group in polymer (A) also varies depending on the type of polymer (A), and may be in the side chain, at the molecular end, or both, but it is preferable that the carboxyl group be present in at least the side chain. For example, in the case of polymer (A) being polyisoprene (A1) having a carboxyl group, it is preferable that the carboxyl group is bonded to the carbon atom at position 4 of the main chain of the isoprene monomer unit, and that one or more (preferably one) hydrogen atoms bonded to the carbon atom are substituted with the following formula: -R1-COOH. In the formula, R1 is a divalent alkyl group (for example, a C1-C5 divalent alkyl group, preferably a methylene group), or -R2(COOR3)- (where R2 is a C1-C5 trivalent alkyl group, preferably -CH-, and R3 is a C1-C5 monovalent alkyl group, preferably a methyl group). When polymer (B) is a polysiloxane (A2) having a carboxyl group, it is preferable that the carboxyl group is bonded to the silicon atom of the siloxane monomer unit, and that one or more (preferably one) hydrogen atoms bonded to the silicon atom are substituted with the following formula: -R4-COOH. R4 is a divalent alkyl group (for example, a C1-C5 divalent alkyl group, preferably a methylene group).

[0015] The carboxyl group equivalent of rubber polymer (A) is preferably 150 g / mol or more, more preferably 200 g / mol or more, and even more preferably 250 g / mol or more. The upper limit is preferably 40,000 g / mol or less, more preferably 300,000 or less, and even more preferably 20,000 g / mol or less. Therefore, 150 to 40,000 g / mol is preferred, 200 to 30,000 g / mol is more preferred, and 250 to 20,000 g / mol is even more preferred.

[0016] -Raw rubber polymer- The raw material rubber polymer, which is the raw material of the carboxyl group-modified rubber polymer (A), includes various natural and synthetic rubbers such as polyisoprene, polysiloxane, hydrogenated polyisoprene, polybutadiene, styrene-butadiene copolymer, isobutylene-isoprene copolymer, ethylene-propylene copolymer, ethylene-propylene-diene terpolymer, etc. Among these, polyisoprene (isoprene polymer) and polysiloxane (silicone polymer) are preferred.

[0017] -Method for Producing Carboxyl Group-Modified Rubber Polymer- The method for producing the carboxyl group-modified rubber polymer (A) is not particularly limited. For example, there are methods of copolymerizing a monomer having a group containing a carboxyl group together with a base polymer during the production of the raw material rubber polymer, and methods of graft-polymerizing a monomer having a group containing a carboxyl group after the production of the rubber polymer.

[0018] -Physical Properties of Carboxyl Group-Modified Rubber Polymer- The mass average molecular weight of the carboxyl group-modified rubber polymer (A) (for example, in the case of the carboxyl group-modified isoprene polymer (A1)) is preferably 5,000 or more, more preferably 10,000 or more, and even more preferably 20,000 or more. The upper limit is preferably 1,000,000 or less, more preferably 900,000 or less, and even more preferably 800,000 or less. Therefore, it is preferably 5,000 to 1,000,000, more preferably 10,000 to 900,000, and even more preferably 20,000 to 800,000. The mass average molecular weight can be measured as the mass average molecular weight in terms of polystyrene by gel permeation chromatography (GPC).

[0019] The number average molecular weight of the carboxyl group-modified rubber polymer (A) (for example, in the case of the carboxyl group-modified silicone polymer (A2)) is preferably 700 or more, more preferably 900 or more, still more preferably 1,000 or more. The upper limit is preferably 700,000 or less, more preferably 600,000 or less, still more preferably 500,000 or less. Therefore, it is preferably from 700 to 700,000, more preferably from 900 to 600,000, still more preferably from 1,000 to 500,000. Thereby, the adhesiveness of the obtained rubber polymer to the base material and the disintegration property can be improved, and the flexibility can be enhanced.

[0020] The carboxyl group equivalent of the carboxyl group-modified isoprene polymer (A1) is preferably from 700 to 40,000 g / mol, more preferably from 1,000 to 30,000 g / mol, still more preferably from 2,000 to 20,000 g / mol. The carboxyl group equivalent of the carboxyl group-modified silicone polymer (A2) is preferably from 150 to 10,000 g / mol, more preferably from 200 to 8,000 g / mol, still more preferably from 250 to 5,000 g / mol. Thereby, the crosslinking reaction with the compound (B) can proceed more rapidly.

[0021] The carboxyl group-modified rubber polymer (A) may be one kind or a combination of two or more kinds, but preferably contains the carboxyl group-modified isoprene polymer (A1) and / or the carboxyl group-modified silicone polymer (A2).

[0022] [1.2 (B) Compound having two or more epoxy groups] The structural unit (II) is a structural unit derived from a compound (B) having two or more epoxy groups (hereinafter sometimes simply referred to as the compound (B)).

[0023] -Epoxy group- The compound (B) has an epoxy group. The number of epoxy groups possessed by the compound (B) is preferably 2 or more. The position of the epoxy group may be at the molecular terminal, side chain, or both, but it is more preferably including the molecular terminal, and even more preferably including both terminals.

[0024] Compound (B) may be a compound having a group containing an epoxy group. Examples of groups containing an epoxy group include a glycidyl group, an oxyranyl methoxy group, and a diglycidylamino group. Compound (B) only needs to have two or more epoxy groups or groups containing epoxy groups, and may have three or more, four or more, or more.

[0025] -Tertiary amine- Compound (B) may further contain a tertiary amine. This allows the tertiary amine to act as a base in the crosslinking reaction (ester bond formation by epoxy ring-opening reaction) between the carboxyl group of (A) and the epoxy group of (B), thereby promoting bonding. There should be one or more tertiary amines in the structure of the compound, and two or more are preferred. The tertiary amine is preferably included in the compound as a diglycidylamino group.

[0026] In this specification, among compounds (B), those having two or more epoxy groups and no tertiary amine are referred to as compound (B1), and those having two or more epoxy groups and a tertiary amine are referred to as compound (B2).

[0027] -Example of compound (B)- Compound (B) is preferably a compound that is compatible with component (A).

[0028] Examples of (B1) include compounds containing a structure in which two epoxy groups and / or epoxy-containing groups (e.g., a glycidyl group, an oxyranyl methoxy group) are linked by a divalent alkyl group. The divalent alkyl group may be linear, branched, or cyclic, and may contain saturated or unsaturated bonds, but linear or branched saturated alkyl groups are preferred. The number of carbon atoms in the alkyl group is preferably 1 to 8, more preferably 2 to 7, and even more preferably 3 to 6. Examples of (B1) include 1,4-butanediol diglycidyl ether, 1,2,7,8-diepoxyoctane, neopentyl glycol diglycidyl ether, and epoxy-modified rubber polymers. These can show good compatibility with (A). Among these, 1,4-butanediol diglycidyl ether and epoxy-modified rubber polymers (e.g., epoxy-modified silicone oil) are preferred. When component (A) is (A2), component (B) is preferably epoxy-modified silicone oil. This makes it possible to further enhance the flexibility of bond-exchange type dynamic covalent bond-containing rubber polymers.

[0029] Examples of compounds (B2) having two or more epoxy groups and a tertiary amine include compounds containing a structure in which two diglycidylamino groups are linked by a divalent alkyl group, and compounds containing a structure in which one end has a diglycidylamino group and the other end has an epoxy group, both linked by a divalent alkyl group. The alkyl group may be linear, branched, or cyclic, and may contain saturated or unsaturated bonds, but it is preferable that it contains one or more saturated or unsaturated carbon rings. The number of carbon atoms in the alkyl group is preferably 3 to 20, more preferably 4 to 18, and even more preferably 5 to 16, 5 to 14, or 5 to 13. Examples of (B2) include 4,4'-methylenebis(N,N-diglycidylaniline), N,N'-[1,3-phenylenebis(methylene)]bis[bis(oxiran-2-ylmethyl)amine], 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, and N-[2-methyl-4-(oxiranylmethoxy)phenyl]-N-(oxiranylmethoxy)oxiranimethaneamine. These can show good compatibility with (A). Among these, 4,4'-methylenebis(N,N-diglycidylaniline) is preferred.

[0030] Compound (B) may be one type or a combination of two or more types, and it is preferable that it contains at least compound (B1) and / or (B2). This allows the crosslinking reaction to proceed appropriately and enables the formation of a bond exchange type dynamic covalent bond.

[0031] [1.3 Bond exchange type dynamic covalent bond] The bond-exchange type dynamic covalent bond-containing rubber polymer contains constituent units derived from the rubber polymer (A) and compound (B) described above. The bond-exchange type dynamic covalent bond-containing rubber polymer is a polymer formed by an addition reaction (crosslinking reaction) between the carboxyl group of rubber polymer (A) and the epoxy group of compound (B). An example of the reaction in which rubber polymer (A) and compound (B2) bond, and the resulting bond-exchange type dynamic covalent bond-containing rubber polymer structure, is shown in the following formulas (1) and (2) (where * indicates a bond, Ar represents an alkyl group, and m, n, and l represent integers). [ka] [ka] A bond-exchange type dynamic covalent rubber polymer has covalent bonds (ester bonds) and hydroxyl groups, and the covalent bonds can form bond-exchange type dynamic covalent bonds (ordinary dynamic covalent bonds) within the polymer in the presence of hydroxyl groups. In this specification, a bond-exchange type dynamic covalent bond is a covalent bond (ester bond) that can simultaneously dissociate and recombine to other hydroxyl groups under external stimuli. An example of dissociation and recombination is shown in the following formulas (3) and (4) (the definition of substituents in the formulas is the same as in formulas (1) and (2)). [ka] [ka] Thus, complete dissociation does not occur during the reaction intermediate state, and new bonds can be formed without losing the connectivity of the polymer chains. As a result, it can be easily adhered to the sealing portion of the substrate, and peeling after use and repeated processes are possible. Furthermore, because it has self-healing properties, it has a long material life, making it easy to reuse and recycle, and thus useful as an environmentally friendly sealing material.

[0032] External stimuli include, for example, heating. The heating temperature can be set appropriately depending on the type of substrate, and is preferably 100°C or higher, preferably 110°C or higher, and more preferably 120°C or higher. The upper limit is preferably 200°C or lower, more preferably 190°C or lower, and even more preferably 180°C or lower. The heating time is, for example, 5 minutes or more, preferably 10 minutes or more, and more preferably 15 minutes or more.

[0033] The ratio of epoxy groups in compound (B) to carboxyl groups in rubber polymer (A) is preferably carboxyl groups:epoxy groups (equivalent ratio) = 1.0:0.5 to 1.0:2.0, more preferably 1.0:0.5 to 1.0:1.5. This allows the crosslinking reaction to proceed sufficiently and enables the formation of a suitable number of bond-exchange type covalent bonds. The hydroxyl group equivalent of compound (B) is preferably 50 or more, more preferably 60 or more, and even more preferably 70 or more. The upper limit is preferably 150 or less, more preferably 140 or less, and even more preferably 130 or less.

[0034] [1.4. Transesterification catalyst (C)] The composition preferably contains a transesterification catalyst (C) (hereinafter sometimes simply referred to as catalyst (C)). This makes it easier for the ester bonds in the bond-exchange type dynamic covalent-containing rubber polymer to function as bond-exchange type covalent bonds. In particular, when compound (B) is compound (B1), it is preferable to include catalyst (C). This can promote the transesterification reaction.

[0035] The transesterification catalyst (C) is not particularly limited as long as it is a catalyst such as an acid catalyst or metal catalyst involved in the bond exchange reaction, i.e., the transesterification reaction, in rubber polymers. Examples include zinc acetate, zinc acetylacetone(II) salt, triphenylphosphine, and 1,5,7-triazabicyclo[4.4.0]deca-5-ene. The transesterification catalyst may be used alone or in combination of two or more types.

[0036] The content of catalyst (C) is preferably 0.01 parts by mass or more, more preferably 0.1 parts by mass or more, per 100 parts by mass of rubber polymer (A). This allows the catalyst to function well. The upper limit is preferably 10 parts by mass or less, more preferably 1 part by mass or less. This suppresses the influence on the properties of the bond-exchange type dynamic covalent bond-containing rubber polymer.

[0037] [2.Optional ingredients] The composition of the present invention may optionally contain other components. Examples of other components include a reinforcing agent (D) and a crosslinking reaction catalyst (E).

[0038] -Reinforcement material (D)- By incorporating a reinforcing material (D), the properties of the resulting composition, such as hardness, tensile strength, and elongation, can be improved. Examples of reinforcing materials include crosslinked rubbers such as silica, carbon, talc, and mica, with silica and carbon being preferred. Hydrophobic silica is preferred. In this specification, hydrophobic silica refers to silica whose surface has been subjected to a hydrophobic treatment. Hydrophobic silica can further improve the dispersibility of the rubber polymer (A). The reinforcing material may be used alone or in combination of two or more types. The content of the reinforcing material can be adjusted according to the desired properties of the rubber polymer; for example, 5 to 30 parts by mass and more than 10 to 25 parts by mass per 100 parts by mass of polymer (A) is preferred.

[0039] -Crosslinking reaction catalyst (E)- By using a crosslinking catalyst, the bonding between polymer (A) and compound (B), specifically the addition reaction (crosslinking reaction) between the carboxyl group of polymer (A) and the epoxy group of compound (B), can be accelerated, allowing for the production of rubber polymers in a shorter time. Examples of crosslinking catalysts include tertiary amines and imidazoles, which can be appropriately determined based on the types of polymer (A) and compound (B). One type of crosslinking catalyst may be used alone, or two or more types may be used in combination. The content of the crosslinking catalyst should be appropriately determined depending on the materials used, crosslinking conditions, etc. For example, 0.1 to 5 parts by mass, and more preferably 0.1 to 1 part by mass, is preferred per 100 parts by mass of polymer (A).

[0040] The composition of the present invention may contain components other than those described in (D) and (E) above. Examples include preservatives, antioxidants, surfactants, light stabilizers, colorants, and the like.

[0041] [3. Method for producing the composition] A method for producing the composition of the present invention includes, for example, a rubber polymer composition preparation step and a crosslinking step. This method allows for the simple production of a rubber polymer composition through relatively simple steps.

[0042] [3.1 Step (1): Rubber Polymer Composition Preparation Step] In step (1), the rubber polymer (A), compound (B), and any additional materials as needed are mixed together and stirred to prepare the rubber polymer composition. The order in which the materials are added is not particularly limited; they may be added all at once or sequentially. Stirring with shear force is preferred, and it is preferable to use a stirrer such as a blade stirrer.

[0043] When compounding each material, the rubber polymer (A) is preferably in liquid form. For example, in the case of (A1), side-chain carboxyl group-modified liquid polyisoprene is preferred, and in the case of (A2), carboxyl group-modified silicone oil is preferred. This makes it possible to increase the molecular weight of the resulting polymer.

[0044] As mentioned above, when compound (B1) is used, it is preferable to further use catalyst (C). When adding catalyst (C) and / or (E), which are used as needed, to the system, it is preferable to use a solvent. This makes it easier to mix with other materials even when using catalysts that are difficult to dissolve (e.g., in powder form). In this case, for example, the catalyst may be dissolved in a solvent to prepare a catalyst solution, and the remaining materials may be added to this. Examples of solvents include chloroform, methanol, ethanol, and a mixture of two or more solvents selected from these. The concentration of the catalyst in the catalyst solution is preferably 1.0 mg / mL or higher, more preferably 2.5 mg / mL or higher. This can increase production efficiency. The upper limit is preferably 20 mg / mL or less, and more preferably 10 mg / mL or less. This can avoid situations where the catalyst does not dissolve.

[0045] When preparing a rubber polymer composition using a catalyst solution, it is preferable to remove the solvent prior to the next step (2). This increases the heating efficiency in step (2) and allows the crosslinking reaction to proceed more effectively.

[0046] [3.2 Step (2): Crosslinking step] In step (2), the rubber polymer composition is heated to allow the crosslinking reaction to proceed. The heating temperature can be appropriately determined considering the type of material, physical properties such as melting point and softening point, productivity, etc., but for example, it is 120 to 150°C. In addition, a reduced pressure treatment may be performed during heating. This can accelerate the crosslinking reaction and shorten the crosslinking time.

[0047] [4.Adhesive] The composition of the present invention can be used as an adhesive. The substrate to which the adhesive is applied is preferably a substrate containing a material having ester groups or hydroxyl groups on its surface. This allows it to bond with the bond-exchange type dynamic covalent bonds of the rubber polymer. Hydroxyl and ester groups on the substrate surface can be introduced by surface treatment (e.g., plasma treatment, UV treatment, corona treatment). Examples of substrates include resin substrates such as nylon, polyimide, polyphenylene sulfide, and polyether ether ketone, and metal substrates such as stainless steel, aluminum, and iron. The applications of the substrate are not particularly limited and include various fields such as vehicles (automobiles, trains, aircraft, etc.), electrical and electronic components, medical equipment, household goods, and daily necessities.

[0048] When using the composition of the present invention as an adhesive, one method of bonding the substrate is to apply an external stimulus (e.g., heating) to the composition and then cool it while it is in contact with the bonding portion of the substrate. The adhesive can also be peeled off by heating it again. After disassembly, it can be used again as an adhesive for the same substrate or other substrates.

[0049] The composition of the present invention can be used as an adhesive for various applications. Specifically, the composition of the present invention can bond to the surface of a substrate using bond-exchange type dynamic covalent bonding. Furthermore, because it behaves as a crosslinked resin at room temperature, it is hard and tough, and has poor vibration and shock resistance, thus exhibiting high adhesiveness. Moreover, because it also possesses the elasticity characteristic of rubber, it can exhibit high adhesiveness regardless of the shape of the substrate surface, even without reinforcement such as screw fastening. Furthermore, because the bond-exchange type dynamic covalent bonding simultaneously detaches and recombines when subjected to external stimuli (heating), it can exhibit a certain degree of viscosity, which prevents dripping when applied to gaps in the substrate or voids between substrates, resulting in good workability. Therefore, the composition of the present invention can be used as an adhesive for container sealing (bonding between the lid and the container) and waterproofing. [Examples]

[0050] Next, the present invention will be described in detail with reference to examples. However, the following examples represent only one aspect of the present invention, and the present invention is not limited thereto.

[0051] Example 1 An isoprene polymer composition was prepared by adding 100 parts by mass of side-chain carboxyl group-modified liquid polyisoprene (LIR-410, manufactured by Kuraray Co., Ltd., carboxyl group equivalent: 3,000 g / mol, mass-average molecular weight: 30,000) as the carboxyl group-modified isoprene rubber polymer (A1) and 3.5 parts by mass of 4,4'-methylenebis(N,N-diglycidylaniline) (hydroxyl group equivalent: 105.5) as (B2) to a planetary mixer and stirring for 15 minutes. Next, the prepared isoprene polymer composition was removed and crosslinked at a temperature of 150°C for 1 hour. The blending ratio of rubber polymer (A1) to compound (B2) was adjusted so that the equivalent ratio of carboxyl groups to epoxy groups was 1:1 (epoxy group amount / carboxyl group amount = 1).

[0052] Example 2 The compound (A2) consists of 100 parts by mass of side-chain carboxyl group-modified silicone oil (Shin-Etsu Chemical Co., Ltd. "X-22-3710E", number average molecular weight: 1,000, carboxyl group equivalent: 1,450 g / mol), 4,4'-methylenebis(N,N-diglycidylaniline) as compound (B2), and silica powder (Hydrophobic fumed silica surface-treated with hexamethyldisilazane, EVONIK "AEROSIL® RX200", specific surface area 200 m²) as reinforcing material (D). 2 20 parts by mass of ( / g) were placed in a planetary mixer and stirred for 5 minutes to prepare a silicone composition. Next, the silicone composition was removed and crosslinked at a temperature of 120°C and under reduced pressure of approximately 2666 Pa for 4 hours. The ratio of rubber polymer (A2) to compound (B2) was adjusted so that the equivalent ratio of carboxyl groups to epoxy groups was 1:1 (amount of epoxy groups / amount of carboxyl groups = 1).

[0053] Comparative Example 1 100 parts by mass of natural rubber, 2.23 parts by mass of Sulfax T10, 3.5 parts by mass of Suncellar CZ-G, and 20 parts by mass of Showblack N330 were mixed together using a roll mill and crosslinked at a temperature of 150°C for 20 minutes to produce a sulfur-crosslinked isoprene polymer, which was then used as is.

[0054] Comparative Example 2 Two-component curing silicone rubber (Shin-Etsu Chemical Co., Ltd., KE-1950-40 A / B) was used as is.

[0055] Comparative Example 3 A two-component epoxy adhesive (ThreeBond Co., Ltd., TB2082C) was used as is.

[0056] [Evaluation Method] -Adhesiveness- Samples of the examples and comparative examples (length × width × thickness = 10cm × 10cm × 0.1cm) were sandwiched between substrates (66 nylon (PA66), size length × width = thickness = 10cm × 10cm × 0.1cm) that had undergone surface treatment (plasma treatment or UV treatment), and bonded at 150°C for 20 minutes. The bonded samples were evaluated according to the following criteria. ○: Tensile shear test was conducted, and the peel force was 0.1 MPa or greater. ×: Not glued at all

[0057] -Drip occurs- The presence or absence of dripping during the pressurization and adhesion of the sample to the substrate in the examples and comparative examples was visually evaluated.

[0058] -Disassembly- In evaluating adhesion, a peel test was performed after the bonding treatment while reheating at 150°C for 20 minutes, and the results were evaluated according to the following criteria. ○: Peelable ×: Not removable

[0059] [Table 1]

[0060] In Comparative Examples 1-3, which lacked the bond-exchange type dynamic covalent bond, adhesion was either absent or, even if adhesion was observed, decomposition was poor. In Comparative Example 3, dripping occurred during adhesion. In contrast, in Examples 1 and 2, which possessed the bond, both adhesion and decomposition were excellent, and dripping was suppressed. These results indicate that the sealing composition of the present invention is an adhesive that is detachable from the substrate, environmentally friendly, and easy to work with. [Industrial applicability]

[0061] The adhesive composition of the present invention can be used as an adhesive in various products, such as for automobiles and other vehicles.

Claims

1. Constituent unit (I): A constituent unit derived from a carboxyl group-modified rubber polymer (A), which is a carboxyl group-modified isoprene polymer (A1) and / or a carboxyl group-modified silicone polymer (A2), Constituent unit (II): A constituent unit derived from a compound (B) having two or more epoxy groups Includes, The connecting portion of the constituent units (I) and (II) includes a covalent bond formed by the exchange of bonds between the carboxyl group of the polymer (A) and the epoxy group of the compound (B). An elastic adhesive composition containing a bond-exchange type dynamic covalent bond-containing rubber polymer.

2. The composition according to claim 1, wherein the mass-average molecular weight of the isoprene polymer (A1) is 5,000 to 1,000,000.

3. The composition according to claim 1, wherein the number average molecular weight of the silicone polymer (A2) is 700 to 40,000.

4. The composition according to any one of claims 1 to 3, wherein the carboxyl group equivalent of the carboxyl group-modified rubber polymer (A) is 150 to 40,000 g / mol.

5. The composition according to claim 1 or 2, wherein the compound (B) comprises one or more compounds (B1) selected from epoxy group-modified silicone oil, 1,4-butanediol diglycidyl ether, 1,2,7,8-diepoxyoctane, and neopentyl glycol diglycidyl ether.

6. The composition according to claim 1 or 2, wherein the compound (B) further comprises a compound (B2) having a tertiary amine structure.

7. The composition according to claim 6, wherein the compound (B2) comprises one or more compounds selected from 4,4'-methylenebis(N,N-diglycidylaniline), N,N'-[1,3-phenylenebis(methylene)]bis[bis(oxiran-2-ylmethyl)amine], 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, and N-[2-methyl-4-(oxiranylmethoxy)phenyl]-N-(oxiranylmethoxy)oxiranimethaneamine).

8. The composition according to claim 1 or 2, wherein the bond-exchange type dynamic covalent bond-containing rubber polymer is a polymer obtained by crosslinking the polymer (A) and the compound (B) with a transesterification catalyst (C).

9. The composition according to claim 8, wherein the catalyst (C) comprises one or more selected from zinc acetate, zinc acetylacetone(II) salt, triphenylphosphine, and 1,5,7-triazabicyclo[4.4.0]deca-5-ene.

10. The composition according to claim 7, wherein the polymer (A) is liquid when crosslinked.

11. The composition according to claim 1 or 2, which is an elastic adhesive for vehicles.

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