JP2014231543A - Bonding method and surface-modified elastic body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an environment friendly bonding method which can firmly bond vulcanized rubber and a thermoplastic elastomer using a photopolymerization method having a simple polymerization method, and enables easy peeling thereof, and to provide a surface-modified elastic body obtained by the boding method.SOLUTION: A bonding method for a plurality of modified elastic bodies includes: a step 1 of forming a polymerization initiation point on the surface of an object to be modified of vulcanized rubber or a thermoplastic elastomer; a step 2 of irradiating UV light of 300-400 nm using the polymerization initiation point as a starting point to radical-polymerize a hydrophilic monomer to grow a hydrophilic polymer chain; and a step 3 of sticking a plurality of obtained modified elastic bodies to each other.

Description

The present invention relates to an adhesion method and a surface-modified elastic body obtained by the adhesion method.

As a method of bonding various materials such as vulcanized rubber and thermoplastic elastomer, a method using an adhesive is common, but it is difficult to peel off once bonded, and it is difficult to repeatedly use bonding and peeling. There is.

On the other hand, a method of generating and adhering a polymer brush on a silicon substrate using surface-initiated atom transfer radical polymerization has also been proposed, but atom transfer radical polymerization requires a complicated polymerization process, and vulcanized rubber There are no proposals for application to bonding of thermoplastic elastomer surfaces.

Polymer Science Society Proceedings Vol. 60, no. 1 (2011) P812 Polymer Science Society Proceedings Vol. 60, no. 2 (2011) P3589-P3590

The present invention solves the above-mentioned problems and uses a photopolymerization method with a simple polymerization method, and can easily and firmly bond a vulcanized rubber and a thermoplastic elastomer, and can be easily peeled off and is environmentally friendly. It is an object to provide a method and a surface-modified elastic body obtained by the bonding method.

The present invention is a method for adhering a plurality of modified elastic bodies, comprising a step 1 for forming a polymerization initiation point on the surface of a vulcanized rubber or thermoplastic elastomer modification target, and the polymerization initiation point as a starting point. , A step 2 of radically polymerizing a hydrophilic monomer by irradiation with UV light of 300 to 400 nm to grow a hydrophilic polymer chain, and a step 3 of bonding a plurality of obtained modified elastic bodies together .

In the step 1, a photopolymerization initiator is adsorbed on the surface of the object to be modified, or UV light of 300 to 400 nm is further irradiated to form a polymerization initiation point from the photopolymerization initiator on the surface. Preferably there is.

In the step 3, it is preferable that water is attached to the surface of the modified elastic body and bonded.

The present invention is also a method for adhering a plurality of modified elastic bodies, wherein the surface of the vulcanized rubber or thermoplastic elastomer modification object is irradiated with UV light of 300 to 400 nm in the presence of a photopolymerization initiator. Then, the present invention relates to an adhesion method including a step I of radically polymerizing a hydrophilic monomer to grow a hydrophilic polymer chain and a step II of bonding a plurality of obtained modified elastic bodies.

In the step II, water is preferably adhered to the surface of the modified elastic body and bonded.
The photopolymerization initiator is preferably a benzophenone compound and / or a thioxanthone compound.

In the bonding method, it is preferable that an inert gas is introduced into the reaction vessel and the reaction liquid at the time of the light irradiation or before the irradiation, and the polymerization is performed by replacing the inert gas atmosphere.
The hydrophilic monomer preferably includes a monomer having a positive charge and a monomer having a negative charge.

As the hydrophilic monomer, at least one selected from the group consisting of an alkali metal acrylate, an amine acrylate, an alkali metal methacrylate, and an amine methacrylate can be suitably used.

Examples of the hydrophilic monomer include alkali metal acrylates, alkali metal methacrylates, alkali metal itaconates, 2-sulfoethyl (meth) acrylate alkali metal salts, 3-sulfopropyl (meth) acrylate alkali metal salts, and 2 -At least 1 sort (s) selected from the group which consists of acrylamide-2-methylpropanesulfonic acid alkali metal salts can also be used conveniently.

As the hydrophilic monomer, 2-((meth) acryloyloxy) ethyltrimethylammonium chloride can also be suitably used.

The hydrophilic monomer (liquid) or a solution thereof contains a polymerization inhibitor and is preferably polymerized in the presence of the polymerization inhibitor. Here, the polymerization inhibitor is preferably 4-methylphenol.
The length of the hydrophilic polymer chain is preferably 10 to 50000 nm.

The present invention relates to a surface-modified elastic body obtained by the bonding method.
The present invention relates to a surface-modified elastic body in which at least part of a three-dimensional solid surface obtained by the bonding method is bonded. Here, the surface-modified elastic body is preferably a polymer brush.

According to the present invention, the step 1 of forming a polymerization starting point on the surface of the vulcanized rubber or thermoplastic elastomer modification target, and the irradiation of 300 to 400 nm UV light starting from the polymerization starting point. Adhesion method for a plurality of modified elastic bodies, including a step 2 for radical polymerization of a hydrophilic monomer to grow a hydrophilic polymer chain, and a step 3 for bonding the obtained plurality of modified elastic bodies, and vulcanization A step of growing a hydrophilic polymer chain by radically polymerizing a hydrophilic monomer by irradiating the surface of a modification target of rubber or thermoplastic elastomer with UV light of 300 to 400 nm in the presence of a photopolymerization initiator; The method of bonding a plurality of modified elastic bodies including the step II of laminating the obtained plurality of modified elastic bodies, so that the surfaces of two or more vulcanized rubbers and thermoplastic elastomers are respectively modified, Water etc. To each other modified surface can be easily and firmly bonded with. In addition, the modified elastic body after bonding can be easily peeled off using an aqueous solution containing an electrostatic charge and a negative charge such as water or saline, so that repeated use of bonding and peeling is possible. This is also desirable from an environmental point of view.

An example of the schematic diagram of the adhesion | attachment method.

The present invention is a method for adhering a plurality of modified elastic bodies, comprising a step 1 for forming a polymerization initiation point on the surface of a vulcanized rubber or thermoplastic elastomer modification target, and the polymerization initiation point as a starting point. , A step 2 of radically polymerizing the hydrophilic monomer by irradiating 300 to 400 nm UV light to grow a hydrophilic polymer chain, and a step 3 of laminating the obtained plurality of modified elastic bodies.

In step 1, a polymerization starting point is formed on the surface of the rubber after vulcanization molding or the thermoplastic elastomer (subject to be modified) after molding.

Examples of rubbers to be modified include silicone rubber, fluorine rubber, natural rubber, deproteinized natural rubber, styrene butadiene rubber, butadiene rubber, isoprene rubber, butyl rubber containing halogenated isoprene units, halogenated butyl rubber, etc. Is mentioned. Examples of the thermoplastic elastomer include polyethylene terephthalate, polystyrene, polycarbonate, polytetrafluoroethylene, and polydimethylsiloxane. The rubber vulcanization conditions may be set as appropriate, and the rubber vulcanization temperature is preferably 140 ° C. or higher, more preferably 170 ° C. or higher, and still more preferably 175 ° C. or higher.

The polymerization starting point is formed, for example, by adsorbing a photopolymerization initiator on the surface of the modification target, and can be formed without irradiating light such as UV. Examples of the photopolymerization initiator include carbonyl compounds, organic sulfur compounds such as tetraethylthiuram disulfide, persulfides, redox compounds, azo compounds, diazo compounds, halogen compounds, and photoreductive dyes. Carbonyl compounds are preferred.

（式において、Ｒ^１〜Ｒ^５及びＲ^１′〜Ｒ^５′は、同一若しくは異なって、水素原子、アルキル基、ハロゲン（フッ素、塩素、臭素、ヨウ素）、水酸基、１〜３級アミノ基、メルカプト基、又は酸素原子、窒素原子、硫黄原子を含んでもよい炭化水素基を表し、隣り合う任意の２つが互いに連結し、それらが結合している炭素原子と共に環構造を形成してもよい。） As the carbonyl compound as the photopolymerization initiator, benzophenone and its derivatives are preferable. For example, a benzophenone-based compound represented by the following formula can be suitably used.

(Wherein R ^{1 to} R ⁵ and R ¹ ′ to R ⁵ ′ are the same or different and represent a hydrogen atom, an alkyl group, a halogen (fluorine, chlorine, bromine, iodine), a hydroxyl group, a primary to tertiary amino group, It represents a mercapto group or a hydrocarbon group that may contain an oxygen atom, a nitrogen atom, or a sulfur atom, and any two adjacent groups may be linked together to form a ring structure together with the carbon atoms to which they are bonded. )

Specific examples of benzophenone compounds include benzophenone, xanthone, 9-fluorenone, 2,4-dichlorobenzophenone, methyl o-benzoylbenzoate, 4,4'-bis (dimethylamino) benzophenone, 4,4'-bis ( And diethylamino) benzophenone. Among these, benzophenone, xanthone, and 9-fluorenone are particularly preferable because a polymer brush can be obtained satisfactorily.

As the benzophenone compound, a fluorobenzophenone compound can also be suitably used, and examples thereof include 2,3,4,5,6-pentafluorobenzophenone and decafluorobenzophenone.

（式中、Ｒ^１１〜Ｒ^１４及びＲ^１１′〜Ｒ^１４′は、同一若しくは異なって、水素原子、ハロゲン原子、アルキル基、環状アルキル基、アリール基、アルケニル基、アルコキシ基、又はアリールオキシ基を表す。） As the photopolymerization initiator, a thioxanthone compound can also be suitably used because it has a high polymerization rate and easily adsorbs and / or reacts with rubber or the like. For example, a compound represented by the following formula can be preferably used.

(In the formula, R ^{11 to} R ¹⁴ and R ¹¹ ′ to R ¹⁴ ′ are the same or different and each represents a hydrogen atom, a halogen atom, an alkyl group, a cyclic alkyl group, an aryl group, an alkenyl group, an alkoxy group, or an aryloxy group. Represents.)

Examples of the thioxanthone compound represented by the above formula include thioxanthone, 2-isopropylthioxanthone, 4-isopropylthioxanthone, 2,3-diethylthioxanthone, 2,4-diethylthioxanthone, 2,4-dichlorothioxanthone, 2-methoxythioxanthone, 1 -Chloro-4-propoxythioxanthone, 2-cyclohexylthioxanthone, 4-cyclohexylthioxanthone, 2-vinylthioxanthone, 2,4-divinylthioxanthone, 2,4-diphenylthioxanthone, 2-butenyl-4-phenylthioxanthone, 2-methoxythioxanthone , 2-p-octyloxyphenyl-4-ethylthioxanthone and the like. Among ^them, one or two of R 11 ^{to R 14} and ^R 11 ^{'~R 14',} is preferably one in particular two are substituted by an alkyl group, have UV absorption in the 384 nm, 365 nm and / Alternatively, 2,4-Diethylthioxanthone (2,4-diethylthioxanthone) is particularly preferable from the viewpoint of high absorption efficiency of 375 nm UV light.

As a method for adsorbing a photopolymerization initiator such as a benzophenone compound or a thioxanthone compound on the surface of the object to be modified, a known method may be used. For example, for benzophenone compounds and thioxanthone compounds, the surface portion of the object to be modified is adsorbed on the surface by treatment with a solution obtained by dissolving benzophenone compounds and thioxanthone compounds in an organic solvent, A polymerization initiation point is formed by evaporating the organic solvent by drying as necessary. The surface treatment method is not particularly limited as long as the benzophenone compound solution and the thioxanthone compound solution can be brought into contact with the surface of the object to be modified. For example, the benzophenone compound solution and the thioxanthone compound Application, spraying, immersion in the solution, and the like are preferable. Furthermore, when the surface modification is necessary only on a part of the surface, the photopolymerization initiator may be adsorbed only on the part of the necessary surface. In this case, for example, application of the solution, Spraying or the like is preferable. As the solvent, methanol, ethanol, acetone, benzene, toluene, methyl ethyl ketone, ethyl acetate, THF, and the like can be used. Acetone is preferable because it does not swell the object to be modified, and is quick to dry and evaporate.

In addition, after a surface treatment with the benzophenone-based compound solution and the thioxanthone-based compound solution is performed on the site to be modified to adsorb the photopolymerization initiator, it is further irradiated with light to be chemically bonded to the surface of the material to be modified. It is preferable. For example, the benzophenone compound and the thioxanthone compound can be immobilized on the surface by irradiation with ultraviolet rays having a wavelength of 300 to 400 nm (preferably 350 to 400 nm).

In Step 2, starting from the polymerization starting point formed in Step 1, UV light of 300 to 400 nm is irradiated to radically polymerize the hydrophilic monomer and grow a hydrophilic polymer chain.

It does not specifically limit as a hydrophilic monomer, A well-known thing can be used. For example, a monomer having a positive charge, a monomer having a negative charge, and the like are included, and it is preferable to use a monomer containing both monomers.

The monomer having a positive charge is not particularly limited as long as it is a monomer having a positive charge in the molecule. For example, a monomer containing an alkali metal salt can be preferably used. The monomer having a negative charge is not particularly limited as long as it is a monomer having a negative charge in the molecule. For example, a monomer containing an amine salt can be preferably used.

Among these, as the hydrophilic monomer, an alkali metal acrylate, an amine acrylate, an alkali metal methacrylate, or an amine methacrylate is preferable. In addition, alkali metal acrylates, alkali metal methacrylates, alkali metal itaconates, 2-sulfoethyl (meth) acrylate alkali metal salts, 3-sulfopropyl (meth) acrylate alkali metal salts, 2-acrylamido-2-methyl Propanesulfonic acid alkali metal salts, and 2-((meth) acryloyloxy) ethyltrimethylammonium chloride can also be suitably used. By using these hydrophilic monomers, strong adhesiveness and good peelability can be obtained.

（式中、Ｒ^２１は−Ｈ又は−ＣＨ_３、Ｘは−Ｏ−又はＮＨ−、ｍは１以上の整数、Ｙは双性イオン性基を表す。） As the hydrophilic monomer, zwitterionic monomers such as carboxybetaine, sulfobetaine, and phosphobetaine (zwitterionic group-containing compound: a compound having a center of permanent positive charge and a center of negative charge) can also be used. As the zwitterionic monomer, a compound represented by the following formula (1) can be used, and among them, a compound represented by the following formula (2) is preferable.

(In the formula, R ²¹ represents —H or —CH ₃ , X represents —O— or NH—, m represents an integer of 1 or more, and Y represents a zwitterionic group.)

In the formula (1), R ²¹ is preferably —CH ₃ , X is —O—, and m is preferably an integer of 1 to 10. In the zwitterionic group represented by Y, examples of the cation include quaternary ammonium such as tetraalkylammonium, and examples of the anion include carboxylic acid, sulfonic acid, and phosphate.

（式中、Ｒ^２１は−Ｈ又は−ＣＨ_３、ｐ及びｑは１以上の整数、Ｙ^１及びＹ^２は反対の電荷を有するイオン性官能基を表す。）

(In the formula, R ²¹ represents —H or —CH ₃ , p and q represent integers of 1 or more, and Y ¹ and Y ² represent ionic functional groups having opposite charges.)

In Formula (2), p is preferably an integer of 2 or more, and more preferably an integer of 2 to 10. q is preferably an integer of 1 to 10, more preferably an integer of 2 to 4. Preferred R ²¹ is the same as described above. Y ¹ and Y ² are the same as the cation and anion.

（式中、Ｒ^２１は水素原子又はメチル基、ｐ及びｑは１〜１０の整数を示す。） Preferable representative examples of the zwitterionic monomer include compounds represented by the following formulas (2-1) to (2-4).

(In the formula, R ²¹ represents a hydrogen atom or a methyl group, and p and q represent an integer of 1 to 10.)

（式中、Ｒ^２１は水素原子又はメチル基、ｐ及びｑは１〜１０の整数を示す。）

(In the formula, R ²¹ represents a hydrogen atom or a methyl group, and p and q represent an integer of 1 to 10.)

（式中、Ｒ^２１は水素原子又はメチル基、Ｒ^２２は炭素数１〜６の炭化水素基、ｐ及びｑは１〜１０の整数を示す。）

(Wherein R ²¹ represents a hydrogen atom or a methyl group, R ²² represents a hydrocarbon group having 1 to 6 carbon atoms, and p and q represent an integer of 1 to 10)

（式中、Ｒ^２１は水素原子又はメチル基、Ｒ^２３、Ｒ^２４及びＲ^２５は、同一若しくは異なって炭素数１又は２の炭化水素基、ｐ及びｑは１〜１０の整数を示す。）

(In the formula, R ²¹ is a hydrogen atom or a methyl group, R ²³ , R ²⁴ and R ²⁵ are the same or different and each is a hydrocarbon group having 1 or 2 carbon atoms;

Examples of the compound represented by the formula (2-1) include compounds represented by the formula (2-2) such as dimethyl (3-sulfopropyl) (2- (meth) acryloyloxyethyl) ammonium betaine. Examples of the compound represented by the formula (2-3) such as dimethyl (2-carboxyethyl) (2- (meth) acryloyloxyethyl) ammonium betaine include dimethyl (3-methoxyphosphopropyl) (2- (meth) acryloyl). Examples of the compound represented by the formula (2-4) such as (oxyethyl) ammonium betaine include 2- (meth) acryloyloxyethyl phosphorylcholine. Examples of zwitterionic monomers include 2- (meth) acryloyloxyethyl carboxybetaine, 2- (meth) acryloyloxyethylsulfobetaine, and the like. Of these, 2- (meth) acryloyloxyethyl sulfobetaine is preferable.

As a method of radical polymerization of the hydrophilic monomer in the step 2, a hydrophilic monomer (liquid) or a solution thereof is applied to the surface of the modification target to which a benzophenone compound, a thioxanthone compound or the like is adsorbed or covalently bonded ( Spraying) or immersing the modification target in a hydrophilic monomer (liquid) or a solution thereof and irradiating with UV light of 300 to 400 nm, radical polymerization (photo radical polymerization) proceeds, and the modification A hydrophilic polymer chain can be grown on the surface of the mass object. Furthermore, after the coating, the surface is covered with transparent glass, PET, polycarbonate or the like, and radical polymerization (photo radical polymerization) is advanced by irradiating UV light of 300 to 400 nm from the surface, and the surface of the object to be modified is applied. On the other hand, hydrophilic polymer chains can also be grown.

Conventionally known materials and methods can be applied to the coating (spraying) solvent, the coating (spraying) method, the dipping method, the irradiation conditions, and the like. In addition, as a solution of a radically polymerizable monomer, the solution which melt | dissolved in the organic solvent which does not melt | dissolve aqueous solution or the photoinitiator (benzophenone type compound, thioxanthone type compound, etc.) to be used is used. Moreover, what contains well-known polymerization inhibitors, such as 4-methylphenol, can also be used as a radically polymerizable monomer (liquid) and its solution.

In the present invention, radical polymerization of a hydrophilic monomer proceeds by irradiating UV light after application of the monomer (liquid) or a solution thereof or after immersion in the monomer or solution thereof. A UV irradiation light source such as a high-pressure mercury lamp, a metal halide lamp, or an LED lamp can be suitably used. The amount of irradiation light may be appropriately set in consideration of the polymerization time and the uniformity of the progress of the reaction. In order to prevent polymerization inhibition due to active gas such as oxygen in the reaction vessel, it is preferable to remove oxygen in the reaction vessel or in the reaction solution at the time of light irradiation or before light irradiation. Therefore, introducing an inert gas such as nitrogen gas or argon gas into the reaction vessel or in the reaction liquid and discharging the active gas such as oxygen out of the reaction system, and replacing the inside of the reaction system with an inert gas atmosphere, Etc. are performed as appropriate. Furthermore, in order to prevent reaction inhibition such as oxygen, a UV irradiation light source is installed at a position where an air layer (oxygen content of 15% or more) does not enter between a reaction vessel such as glass or plastic and a reaction solution or a modification target. A device such as the above is also appropriately performed.

The irradiation wavelength of the UV light in step 2 is 300 to 400 nm. Thereby, a polymer chain can be favorably formed on the surface of the object to be modified. As the light source, a high-pressure mercury lamp, an LED having a central wavelength of 365 nm, an LED having a central wavelength of 375 nm, or the like can be used. Especially, it is preferable to irradiate 300-400 nm LED light, and it is more preferable to irradiate 355-380 nm LED light. In particular, an LED having a center wavelength of 365 nm close to the excitation wavelength of benzophenone of 366 nm is preferable from the viewpoint of efficiency. If the wavelength is less than 300 nm, there is a possibility of damaging the molecule of the modification target, so that light of 300 nm or more is preferable, and from the viewpoint that the damage of the modification target is very small, it is 355 nm or more. More preferred is light. On the other hand, light having a wavelength of 400 nm or less is used from the viewpoint that the polymerization initiator is hardly activated and the polymerization reaction does not proceed easily and the polymerization initiator is more activated. LED light is suitable because it has a narrow wavelength and does not emit a wavelength other than the center wavelength. Even if a mercury lamp or the like is used to cut light of less than 300 nm using a filter, the same effect as LED light can be obtained. It is also possible.

In step 3, a plurality of modified elastic bodies obtained in step 2 are bonded together, that is, a plurality of modified elastic bodies in which hydrophilic polymer chains are grown on the surface of the object to be modified, The hydrophilic polymer chains are brought into contact with each other and bonded (adhered). Thereby, a some modified | denatured elastic body can be adhere | attached firmly and simply. It is also possible to peel easily after bonding.

For example, in the step 3, water (moisture) is applied (attached) to a target site (such as a hydrophilic polymer chain site to be bonded) of the modified elastic body, and a plurality of target sites to be bonded to the modified elastic body are bonded. This can be suitably implemented.

The application method (attachment method) of water to the bonding target site is not particularly limited as long as it is a method capable of bringing water into contact with the bonding target site of the modified elastic body, and dripping water onto the bonding target site. And methods such as spraying and dipping the modified elastic body in water. Moreover, the method of sticking adhesion object site | parts will not be specifically limited if it is a method of contacting adhesion object site | parts, For example, the method of applying a load to the said site | part etc. can be used conveniently.

Specifically, step 3 can be performed by a method as shown in the schematic diagram of FIG. That is, for example, water is dropped on the modified surface of either the modified elastic body in which the polyanion chain is grown or the modified elastic body in which the polycation chain is grown, and then the other modified elasticity is applied to the dripping portion. Two modified elastic bodies can be bonded together by bonding the modified surfaces of the bodies and applying a predetermined load. Moreover, it can also adhere | attach by dripping a water | moisture content on each modification | reformation surface of two modified elastic bodies which grew the hydrophilic polymer chain | strand, then bonding the said dripping parts together and applying a predetermined load.

The present invention is also a method for adhering a plurality of modified elastic bodies, wherein the surface of the vulcanized rubber or thermoplastic elastomer modification object is irradiated with UV light of 300 to 400 nm in the presence of a photopolymerization initiator. Then, it is an adhesion method including a step I of radically polymerizing a hydrophilic monomer to grow a hydrophilic polymer chain and a step II of laminating a plurality of obtained modified elastic bodies. Specifically, hydrophilic monomers are radically polymerized by UV light irradiation using a photopolymerization initiator as an initiator, and a hydrophilic polymer chain is grown on the surface of each modification target to produce a plurality of modified elastic bodies. Further, a plurality of modified elastic bodies can be bonded by bonding the modified surfaces of the modified elastic bodies.

In Step I, starting from the polymerization start point formed from the photopolymerization initiator on the surface of the modification target, the hydrophilic monomer is irradiated with 300 to 400 nm UV light to undergo radical polymerization to grow a hydrophilic polymer chain. It is preferable to make it. For example, in Step I, a photopolymerization initiator and a hydrophilic monomer are brought into contact with the surface of the modification target, and then UV irradiation of 300 to 400 nm is applied to generate a polymerization start point from the photopolymerization initiator. In addition, the hydrophilic polymer chain can be grown by radical polymerization of the hydrophilic monomer starting from the polymerization initiation point.

As a method for radical polymerization of the hydrophilic monomer in Step I, a hydrophilic monomer (liquid) containing a photopolymerization initiator such as a benzophenone compound or a thioxanthone compound or a solution thereof is applied to the surface of the modification target. (Spraying), or by immersing the modification target in a hydrophilic monomer (liquid) containing a photopolymerization initiator or a solution thereof and irradiating with UV light, radical polymerization (photo radical polymerization) proceeds, A hydrophilic polymer chain can be grown on the surface of the modification target. Further, a method of covering with the above-mentioned transparent glass, PET, polycarbonate, etc. and irradiating UV light from the top can also be adopted. For the coating (spraying) solvent, the coating (spraying) method, the dipping method, the irradiation conditions, etc., the same materials and methods as described above can be applied. Step II can be performed in the same manner as in Step 3.

In Step 2 and Step I, by forming a hydrophilic polymer chain, excellent adhesiveness and peelability can be obtained. The degree of polymerization of the formed polymer chain is preferably 20 to 200000, more preferably 350 to 50000.

The length of the hydrophilic polymer chain formed in Step 2 and Step I is preferably 10 to 50000 nm, more preferably 100 to 50000 nm. When it is less than 10 nm, there is a tendency that good adhesion and peelability cannot be obtained. If it exceeds 50000 nm, further improvement in adhesiveness cannot be expected, and the cost of raw materials tends to increase due to the use of expensive monomers, and the surface pattern by the surface treatment becomes visible to the naked eye. There is a tendency to damage.

In Step 2 and Step I, two or more hydrophilic monomers may be radically polymerized simultaneously starting from the polymerization starting point. Further, two or more hydrophilic polymer chains may be laminated. Furthermore, a plurality of polymer chains may be grown on the surface of the modification target. In the surface modification of the modification target, the polymer chains may be cross-linked. In this case, ionic crosslinking, crosslinking with a hydrophilic group having an oxygen atom, and crosslinking with a halogen group such as iodine may be formed between the polymer chains.

By applying the bonding method to vulcanized rubber or thermoplastic elastomer, a surface-modified elastic body in which a plurality of modified elastic bodies are bonded is obtained. For example, by applying the method to at least a part of a three-dimensional solid (such as an elastic body), a surface-modified elastic body to which the solid is bonded can be obtained. Furthermore, a polymer brush (polymer brush) is mentioned as a preferable example of the surface modified elastic body. Here, the polymer brush means a graft polymer obtained by a grafting from method using surface initiated polymerization. As the brush density, quasi-dilute and dense brushes of 0.01 chains / nm ² or more are preferable.

Adhesive modified elastic bodies have strong adhesive properties and can be easily peeled off by treatment with an aqueous solution containing positive and negative charges (such as an aqueous solution containing cations and anions). It is.

Examples of the aqueous solution containing a positive charge and a negative charge include various electrolyte aqueous solutions such as water and a saline solution in which sodium ions and chloride ions are dissolved. The treatment method for the adhesion site of the aqueous solution containing a positive charge and a negative charge is not particularly limited as long as it is a method capable of contacting the aqueous solution to be adhered to the site to be bonded to the modified elastic body. The method of dripping or spraying is mentioned.

EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example, this invention is not limited only to these.

Example 1
Benzophenone is a vulcanized rubber sheet (vulcanized for 10 minutes at 180 ° C .: 2 mm thick) obtained by crosslinking chlorobutyl rubber containing an isoprene unit (unsaturation: 1 to 2%) with triazine (cut to 1 cm × 3 cm after vulcanization). Was immersed in a 1 wt% acetone solution for 5 minutes to adsorb benzophenone on the surface of the vulcanized rubber and dried. Subsequently, the surface of the vulcanized rubber sheet was irradiated with LED-UV light (3.5 mW / cm ² ) having a wavelength of 365 nm for 5 minutes to chemically bond benzophenone.
An aqueous solution (2.5 M) of 3-sulfopropyl methacrylate salt (3-sulfopropyl methacrylate potassium salt) was dropped on the vulcanized rubber sheet and covered with a slide glass, and an LED-UV light having a wavelength of 365 nm (3.5 mW) / Cm ² ) for 4.5 hours to perform radical polymerization to grow polymer chains on the rubber surface. Thereafter, the surface was washed with water and dried.
In addition, a vulcanized rubber sheet obtained by crosslinking chlorobutyl rubber containing an isoprene unit (unsaturation: 1 to 2%) with triazine (vulcanized at 180 ° C. for 10 minutes: 2 mm thick) (cut to 1 cm × 3 cm after vulcanization) ) Was immersed in a 1 wt% acetone solution of benzophenone for 5 minutes to adsorb benzophenone to the surface of the vulcanized rubber and dried. Subsequently, the surface of the vulcanized rubber sheet was irradiated with LED-UV light (3.5 mW / cm ² ) having a wavelength of 365 nm for 5 minutes to chemically bond benzophenone.
An aqueous solution (2.5 M) of {2- (methacryloyloxy) ethyl} trimethylammonium chloride (2-methacryloyloxyethyltrimethylammonium chloride) is hung on a vulcanized rubber sheet and covered with a slide glass. LED-UV having a wavelength of 365 nm Radical polymerization was performed by irradiation with light (3.5 mW / cm ² ) for 4.5 hours to grow polymer chains on the rubber surface. Thereafter, the surface was washed with water and dried.
Next, water is dropped on the modified surfaces of the modified elastic bodies on which the respective polymer chains are grown, and the modified surfaces are bonded so that the 1 cm × 1 cm portions overlap each other, and 1 kg / cm is attached to the bonded portions. A load of ² was applied and allowed to stand for 18 hours.

(Example 2)
Benzophenone is a vulcanized rubber sheet (vulcanized for 10 minutes at 180 ° C .: 2 mm thick) obtained by crosslinking chlorobutyl rubber containing an isoprene unit (unsaturation: 1 to 2%) with triazine (cut to 1 cm × 3 cm after vulcanization). Was immersed in a 1 wt% acetone solution for 5 minutes to adsorb benzophenone on the surface of the vulcanized rubber and dried. Subsequently, the surface of the vulcanized rubber sheet was irradiated with LED-UV light (3.5 mW / cm ² ) having a wavelength of 365 nm for 5 minutes to chemically bond benzophenone.
An aqueous solution (2.5 M) of 3-sulfopropyl methacrylate salt (3-sulfopropyl methacrylate potassium salt) was dropped on the vulcanized rubber sheet and covered with a slide glass, and an LED-UV light having a wavelength of 365 nm (3.5 mW) / Cm ² ) for 2 hours to perform radical polymerization to grow polymer chains on the rubber surface. Thereafter, the surface was washed with water and dried.
In addition, a vulcanized rubber sheet obtained by crosslinking chlorobutyl rubber containing an isoprene unit (unsaturation: 1 to 2%) with triazine (vulcanized at 180 ° C. for 10 minutes: 2 mm thick) (cut to 1 cm × 3 cm after vulcanization) ) Was immersed in a 1 wt% acetone solution of benzophenone for 5 minutes to adsorb benzophenone to the surface of the vulcanized rubber and dried. Subsequently, the surface of the vulcanized rubber sheet was irradiated with LED-UV light (3.5 mW / cm ² ) having a wavelength of 365 nm for 5 minutes to chemically bond benzophenone.
An aqueous solution (2.5 M) of {2- (methacryloyloxy) ethyl} trimethylammonium chloride (2-methacryloyloxyethyltrimethylammonium chloride) is hung on a vulcanized rubber sheet and covered with a slide glass. LED-UV having a wavelength of 365 nm Radical polymerization was performed by irradiation with light (3.5 mW / cm ² ) for 2 hours to grow polymer chains on the rubber surface. Thereafter, the surface was washed with water and dried.
Next, water is dropped on the modified surfaces of the modified elastic bodies on which the respective polymer chains are grown, and the modified surfaces are bonded so that the 1 cm × 1 cm portions overlap each other, and 1 kg / cm is attached to the bonded portions. A load of ² was applied and allowed to stand for 18 hours.

Example 3
2 sheets of vulcanized rubber sheet (unsaturation: 1-2%) containing isoprene units crosslinked with triazine (vulcanized at 180 ° C. for 10 minutes: 2 mm thick) (cut to 1 cm × 3 cm after vulcanization) Was immersed in a 1 wt% acetone solution of benzophenone for 5 minutes to adsorb benzophenone on the surface of the vulcanized rubber and dried. Subsequently, the surface of the vulcanized rubber sheet was irradiated with LED-UV light (3.5 mW / cm ² ) having a wavelength of 365 nm for 5 minutes to chemically bond benzophenone.
An aqueous solution (2.5 M) of 3-sulfopropyl methacrylate salt (3-sulfopropyl methacrylate potassium salt) is separately dropped on two vulcanized rubber sheets and covered with a slide glass. LED having a wavelength of 365 nm Radical polymerization was performed by irradiation with UV light (3.5 mW / cm ² ) for 4.5 hours to grow polymer chains on the rubber surface. Thereafter, the surface was washed with water and dried.
Next, water is dropped on the modified surfaces of the modified elastic bodies on which the respective polymer chains are grown, and the modified surfaces are bonded so that the 1 cm × 1 cm portions overlap each other, and 1 kg / cm is attached to the bonded portions. A load of ² was applied and allowed to stand for 18 hours.

Example 4
2 sheets of vulcanized rubber sheet (unsaturation: 1-2%) containing isoprene units crosslinked with triazine (vulcanized at 180 ° C. for 10 minutes: 2 mm thick) (cut to 1 cm × 3 cm after vulcanization) Was immersed in a 1 wt% acetone solution of benzophenone for 5 minutes to adsorb benzophenone on the surface of the vulcanized rubber and dried. Subsequently, the surface of the vulcanized rubber sheet was irradiated with LED-UV light (3.5 mW / cm ² ) having a wavelength of 365 nm for 5 minutes to chemically bond benzophenone.
An aqueous solution (2.5 M) of {2- (methacryloyloxy) ethyl} trimethylammonium chloride (2-methacryloyloxyethyltrimethylammonium chloride) was separately dropped on two vulcanized rubber sheets and covered with a slide glass of 365 nm. Radiation polymerization was performed by irradiating an LED-UV light (3.5 mW / cm ² ) having a wavelength for 4.5 hours to grow a polymer chain on the rubber surface. Thereafter, the surface was washed with water and dried.
Next, water is dropped on the modified surfaces of the modified elastic bodies on which the respective polymer chains are grown, and the modified surfaces are bonded so that the 1 cm × 1 cm portions overlap each other, and 1 kg / cm is attached to the bonded portions. A load of ² was applied and allowed to stand for 18 hours.

(Example 5)
A polymer chain was formed and bonded in the same manner as in Example 1 except that the vulcanized rubber sheet was changed to a polyethylene terephthalate (PET) sheet.

(Comparative Example 1)
Water is dropped on the surface of two vulcanized rubber sheets (2 mm thick, 1 cm × 3 cm), the two sheets are bonded so that 1 cm × 1 cm overlaps, and a load of 1 kg / cm ² is applied to the bonded portion. Allowed to stand for 18 hours.

(Comparative Example 2)
Lamination was performed in the same manner as in Comparative Example 1 except that the vulcanized rubber sheet was changed to a polyethylene terephthalate (PET) sheet.

The surface-modified elastic bodies produced in Examples and Comparative Examples were evaluated by the following methods.
(Polymer chain length)
The length of the polymer chain formed on the surface of the vulcanized rubber was measured using an SEM at an acceleration voltage of 15 kV and 1000 times the cross section of the modified rubber on which the polymer chain was formed. The film thickness of the polymer layer was taken as the length of the polymer chain.

(Peel test)
The bonded sheet was subjected to a shear peel test using a tensile tester. The test speed was 10 mm / min.

In Examples 1 to 5, moisture was attached to the modified surfaces of the two sheets on which the polymer chains were grown, and the sheets were bonded to each other by bonding. In particular, Examples 1 and 2 were bonded surfaces in the peel test. Does not peel off, resulting in the destruction of the rubber at the end of the bonded portion, and the peel strength was 0.57 MPa or more and 0.56 MPa or more, respectively. Moreover, when the sheet | seat which the Examples 1-5 adhere | attached was immersed in salt solution, it was also possible to peel off easily. On the other hand, good adhesion was not obtained even when moisture was attached to the vulcanized rubber sheet or PET sheet.

Furthermore, what was once adhered in Examples 1 and 2 was peeled off with a saline solution, and then washed with water to remove the salt and dried. Then, adhesion was again performed in the same manner as described above, and a peel test was performed. As a result, a peel strength of 0.57 MPa or more was obtained in Example 1, and a peel strength of 0.55 MPa or more was obtained in Example 2 (rubber was broken).

In this way, by attaching water to the modified surface on which the hydrophilic polymer chain has been grown, it can be adhered extremely firmly, and can be peeled off very easily with saline, and can be repeatedly adhered. It became clear that this is an environmentally friendly bonding method.

Claims (17)

A method of bonding a plurality of modified elastic bodies,
Forming a polymerization initiation point on the surface of the vulcanized rubber or thermoplastic elastomer to be modified; and
Starting from the polymerization initiation point, the step 2 of radically polymerizing the hydrophilic monomer by irradiating with UV light of 300 to 400 nm to grow a hydrophilic polymer chain;
A bonding method including the step 3 of bonding the obtained plurality of modified elastic bodies. In the step 1, a photopolymerization initiator is adsorbed on the surface of the object to be modified, or UV light of 300 to 400 nm is further irradiated to form a polymerization initiation point from the photopolymerization initiator on the surface. The bonding method according to claim 1. The bonding method according to claim 1, wherein in the step 3, water is attached to the surface of the modified elastic body and bonded. A method of bonding a plurality of modified elastic bodies,
Radiation polymerization of a hydrophilic monomer by irradiating 300 to 400 nm of UV light in the presence of a photopolymerization initiator on the surface of a vulcanized rubber or thermoplastic elastomer to be modified to grow a hydrophilic polymer chain I and
A bonding method comprising a step II of bonding the obtained plurality of modified elastic bodies. 5. The bonding method according to claim 4, wherein in the step II, water is attached to the surface of the modified elastic body and bonded. The adhesion method according to claim 2, wherein the photopolymerization initiator is a benzophenone compound and / or a thioxanthone compound. The bonding method according to any one of claims 1 to 6, wherein an inert gas is introduced into a reaction vessel and a reaction solution at the time of the light irradiation or before the irradiation, and the polymerization is performed by replacing the inert gas atmosphere. The adhesion method according to claim 1, wherein the hydrophilic monomer includes a monomer having a positive charge and a monomer having a negative charge. The hydrophilic monomer is at least one selected from the group consisting of an alkali metal acrylate, an amine acrylate, an alkali metal methacrylate, and an amine methacrylate. Bonding method. The hydrophilic monomer includes alkali metal acrylate, alkali metal methacrylate, alkali metal itaconate, 2-sulfoethyl (meth) acrylate alkali metal, 3-sulfopropyl (meth) acrylate alkali metal, and 2- The adhesion method according to any one of claims 1 to 7, wherein the adhesion method is at least one selected from the group consisting of alkali metal acrylamide-2-methylpropanesulfonates. The adhesion method according to claim 1, wherein the hydrophilic monomer is 2-((meth) acryloyloxy) ethyltrimethylammonium chloride. The bonding method according to claim 1, wherein the hydrophilic monomer (liquid) or a solution thereof contains a polymerization inhibitor and is polymerized in the presence of the polymerization inhibitor. The adhesion method according to claim 12, wherein the polymerization inhibitor is 4-methylphenol. The adhesion method according to claim 1, wherein the hydrophilic polymer chain has a length of 10 to 50000 nm. A surface-modified elastic body obtained by the bonding method according to claim 1. A surface-modified elastic body to which at least a part of a three-dimensional solid surface obtained by the bonding method according to claim 1 is bonded. The surface-modified elastic body according to claim 15 or 16, which is a polymer brush.

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