JP2022029159A - Adhesive composition, adhesive structure and belt - Google Patents

Abstract

To provide an adhesive composition that shows excellent adhesion, or more specifically, an adhesive composition that has excellent adhesion both at room temperature and at high temperatures and also has excellent tensile and tearing characteristics when bonding the fibers subjected to various surface treatments and a rubber, and to provide an adhesive structure having excellent interlayer adhesion by use of such an adhesive composition, and a belt.SOLUTION: An adhesive composition for bonding a rubber and fibers contains resorcin and/or a salt thereof, a polyoxazoline compound, and an aqueous polymer dispersion. Alternatively, an adhesive composition for bonding a rubber and fibers contains a polyoxazoline compound, and an aqueous polymer dispersion, where the rubber includes a rubber containing a carboxylated olefin compound. An adhesive structure has a fiber layer, a layer of the adhesive composition, and a rubber layer in the stated order. A belt includes the adhesive structure.SELECTED DRAWING: None

Description

The present invention relates to adhesive compositions, adhesive structures and belts.

Rubber products such as belts are reinforced with fibers. For example, polyester fibers such as polyethylene terephthalate fibers and polyamide fibers such as aramid fibers are used as reinforcing materials in the form of filaments, cords, cables, cord fabrics, canvas and the like.

However, these reinforcing materials have poor adhesiveness to rubber, and attempts have been made to improve the adhesiveness by applying a treatment agent consisting of a resorcin-formalin condensate and rubber latex to the surface of the reinforcing material. In the adhesion between these synthetic fibers and rubber, various adhesive compositions have been used to improve the adhesiveness between rubber and synthetic fibers.

In recent years, from the viewpoint of the environment and the like, there has been a demand for a method of adhering rubber and fibers without using formalin or a component derived from formalin in the production of rubber products.
So far, adhesive compositions for adhering rubber and fibers without using resorcin-formalin condensate have been proposed.

However, when the conventional adhesive composition is used for adhering a fiber and rubber for producing a belt, particularly a transmission belt, the adhesive force and tension at room temperature and high temperature cause the belt to be produced. Occasionally, when using a belt, there may be a problem that the rubber and the fiber are separated from each other. In addition, the adhesive strength was not satisfactory, and it was difficult to achieve both deformalinization and high adhesive strength in the production of rubber products.

Patent Documents 1 and 2 describe an adhesive composition used for adhering rubber and fibers, which comprises a polymer containing a 2-oxazoline group and a rubber latex.
However, this adhesive composition contains a condensate of resorcin and formalin. Further, it is not described that resorcin is blended or that a rubber containing an olefin compound having a carboxyl group is used as the rubber.

Patent Document 3 describes an adhesive composition used for adhering rubber and fibers, which comprises a polymer containing a 2-oxazoline group.
However, it is not described that this adhesive composition contains resorcin or rubber latex, or uses a rubber containing an olefin compound having a carboxyl group as the rubber.

Patent Document 4 describes an adhesive composition used for adhering rubber and fibers, which comprises a polymer containing a 2-oxazoline group and a rubber latex.
However, it is not described that this adhesive composition contains resorcin or uses a rubber containing an olefin compound having a carboxyl group as the rubber.

Japanese Unexamined Patent Publication No. 5-339552 Japanese Unexamined Patent Publication No. 2000-248254 Japanese Unexamined Patent Publication No. 2001-98245 Japanese Unexamined Patent Publication No. 2013-64037

An object of the present invention is to obtain an adhesive composition for adhering fibers and rubber, which exhibits excellent adhesiveness even if it does not contain formalin or a component derived from formalin.
Another object of the present invention is to obtain an adhesive structure having excellent adhesiveness between fibers and rubber and a belt containing the adhesive structure by using such an adhesive composition.

As a result of diligent studies to solve the above problems, the present inventor has found that the above problems can be solved by the following adhesive composition, adhesive structure and belt, and has completed the present invention. Specifically, it is as follows.
[1] An adhesive composition for adhering rubber and fibers, which comprises resorcin and / or a salt thereof, a polyoxazoline compound, and an aqueous polymer dispersion.
[2] An adhesive composition for adhering a rubber and a fiber, which comprises a polyoxazoline compound and an aqueous polymer dispersion, wherein the rubber contains a rubber containing an olefin compound having a carboxyl group. Adhesive composition.
[3] The adhesive composition according to [1] or [2], wherein the polyoxazoline compound is a polymer compound having two or more 2-oxazoline groups.
[4] An adhesive structure comprising a fiber layer, a layer of the adhesive composition according to any one of [1] to [3], and a rubber layer in this order.
[5] A belt including the adhesive structure according to [4].

According to the present invention, in an adhesive composition for adhering fibers and rubber, it is possible to obtain an adhesive composition showing excellent adhesiveness without containing formalin or a component derived from formalin.
Further, according to the present invention, by using such an adhesive composition, it is possible to obtain an adhesive structure having excellent adhesiveness between fibers and rubber, and a belt containing the adhesive structure.

[Adhesive composition]
The adhesive composition of the present invention is the following adhesive composition (1) or (2).
(1) An adhesive composition for adhering rubber and fibers, which comprises resorcin and / or a salt thereof, a polyoxazoline compound, and an aqueous polymer dispersion.
(2) An adhesive composition for adhering a rubber and a fiber, which comprises a polyoxazoline compound and an aqueous polymer dispersion, wherein the rubber contains a rubber containing an olefin compound having a carboxyl group. Adhesive composition.

<Resorcin and / or its salt>
Resorcin is a compound represented by the following structural formula.

The salt of resorcin may be any salt used to form an adhesive composition of rubber and fiber. For example, one or more selected from the group consisting of alkali metals such as sodium and potassium, alkaline earth metals such as calcium and magnesium, organic amines such as ammonium, triethylamine and triethanolamine, and basic amino acids such as lysine and arginine. Salt is given.
In the present invention, one or more selected from the group consisting of resorcin and / or a salt thereof can be used.

Resolcin and / or a salt thereof (R) may be present in the adhesive composition in an unreacted state, and at least a part thereof reacts with the polyoxazoline compound (O) to form an initial condensate (RO). It may exist in the state of.
In the present invention, it is preferable that it is contained in the adhesive composition as an aqueous solution of the initial condensate (RO).

<Polyoxazoline compound>
A polyoxazoline compound is a compound having two or more oxazoline groups in a molecule. For example, one selected from the group consisting of a bisoxazoline compound having two oxazoline groups, a trisoxazoline compound having three oxazoline groups, a polymer compound having a 2-oxazoline group at the side chain and / or the terminal of the polymer, and the like. The above can be mentioned. The polyoxazoline compound may be synthesized and used, or a commercially available compound may be used.

Examples of the bisoxazoline compound having two oxazoline groups include 2,2'-bis (2-oxazoline), 2,2'-bis (4-methyl-2-oxazoline), and 2,2'-bis (5). -Methyl-2-oxazoline), 2,2'-bis (4,4'-dimethyl-2-oxazoline), 2,2'-bis (4-ethyl-2-oxazoline), 2,2'-bis (2,2'-bis (4,4'-dimethyl-2-oxazoline)) 4,4'-diethyl-2-oxazoline), 2,2'-bis (4-propyl-2-oxazoline), 2,2'-bis (4-butyl-2-oxazoline), 2,2'-bis (4-Hexil-2-oxazoline), 2,2'-bis (4-phenyl-2-oxazoline), 2,2'-bis (4-cyclohexazoline), 2,2'-bis (4) -Benzyl-2-oxazoline), 2,2'-p-phenylenebis (2-oxazoline), 2,2'-p-phenylenebis (4-methyl-2-oxazoline), 2,2'-p-phenylene Bis (5-methyl-2-oxazoline), 2,2'-p-phenylenebis (4,4'-dimethyl-2-oxazoline), 2,2'-m-phenylenebis (2-oxazoline), 2, 2'-m-Phenylenebis (4-methyl-2-oxazoline), 2,2'-m-Phenylenebis (5-methyl-2-oxazoline), 2,2'-m-Phenylenebis (4,4') -Dimethyl-2-oxazoline), 2,2'-o-phenylenebis (2-oxazoline), 2,2'-o-phenylenebis (4-methyl-2-oxazoline), 2,2'-o-phenylene Bis (5-methyl-2-oxazoline), 2,2'-o-phenylene bis (4,4'-dimethyl-2-oxazoline), 2,2'-ethylenebis (2-oxazoline), 2,2' -Ethethylene bis (4-methyl-2-oxazoline), 2,2'-ethylene bis (5-methyl-2-oxazoline), 2,2'-ethylene bis (4,4'-dimethyl-2-oxazoline), 2,2'-Tetramethylenebis (2-oxazoline), 2,2'-tetramethylenebis (4-methyl-2-oxazoline), 2,2'-tetramethylenebis (5-methyl-2-oxazoline), 2,2'-Tetramethylenebis (4,4'-dimethyl-2-oxazoline), 2,2'-tetramethylenebis (5,5'-dimethyl-2-oxazoline), 2,2'-hexamethylenebis (2-Oxazoline), 2,2'-Hexamethile Phenyl (4-methyl-2-oxazoline), 2,2'-hexamethylenebis (5-methyl-2-oxazoline), 2,2'-hexamethylenebis (4,4'-dimethyl-2-oxazoline), 2,2'-Hexamethylenebis (5,5'-dimethyl-2-oxazoline), 2,2'-octamethylenebis (2-oxazoline), 2,2'-decamethylenebis (2-oxazoline), 2 , 2'-9,9'-diphenoxyetambis (2-oxazoline), 2,2'-cyclohexylenebis (2-oxazoline), 2,2'-diphenylenebis (2-oxazoline), 1,4 -One or more selected from the group consisting of bis [2- (5-phenyloxazoline)] benzene, bis (2-oxazolinylcyclohexane) sulfide and the like can be mentioned.
Examples of the trisoxazoline compound having three oxazoline groups include 2,2', 2 "-(1,3,5-phenylene) -tris (2-oxazoline) and the like.

Examples of the polymer compound having a 2-oxazoline group at the side chain and / or the terminal of the polymer include a homopolymer of a 2-oxazoline group-containing ethylenically unsaturated monomer and a 2-oxazoline group-containing ethylenically unsaturated monomer. A copolymer obtained by copolymerizing a monomer and an ethylenically unsaturated monomer copolymerizable therewith, a 2-oxazoline group-containing ethylenically unsaturated monomer is graft-polymerized on a polymer main chain. One or more kinds selected from the group consisting of the obtained polymers and the like can be mentioned.

Examples of the 2-oxazoline group-containing ethylenically unsaturated monomer include 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, and 2-vinyl-5-methyl-2-oxazoline, 2. -Vinyl-4-ethyl-2-oxazoline, 2-vinyl-5-ethyl-2-oxazoline, 2-vinyl-4,4-dimethyl-2-oxazoline, 2-vinyl-4,4-diethyl-2-oxazoline , 2-vinyl-4,5-dimethyl-2-oxazoline, 2-vinyl-4,5-diethyl-2-oxazoline, 2-isopropenyl-2-oxazoline, 2-isopropenyl-4-methyl-2-oxazoline , 2-isopropenyl-5-methyl-2-oxazoline, 2-isopropenyl-5-ethyl-2-oxazoline, 2-isopropenyl-4-ethyl-2-oxazoline, 2-isopropenyl-5-ethyl-2 -Oxazoline, 2-isopropenyl-4,4-dimethyl-2-oxazoline, 2-isopropenyl-4,4-diethyl-2-oxazoline, 2-isopropenyl-4,5-dimethyl-2-oxazoline, 2- One or more selected from the group consisting of isopropenyl-4,5-diethyl-2-oxazoline and the like can be mentioned.

The ethylenically unsaturated monomer copolymerizable with the 2-oxazoline group-containing ethylenically unsaturated monomer is not particularly limited as long as it does not react with the oxazoline group. For example, (meth) acrylic acid esters such as methyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate; unsaturated nitriles such as (meth) acrylonitrile; (meth) acrylamide, Unsaturated amides such as N-methylol (meth) acrylamide; Vinyl esters such as vinyl acetate and vinyl propionate; Vinyl ethers such as methyl vinyl ether and ethyl vinyl ether; α-olefins such as ethylene and propylene; Vinyl chloride and chloride Halogenated vinyls such as billiniden and fluoride; one or more selected from the group consisting of α and β-unsaturated aromatic monomers such as styrene and α-methylstyrene.

A homopolymer of a 2-oxazoline group-containing ethylenically unsaturated monomer, a 2-oxazoline group-containing ethylenically unsaturated monomer, and a copolymerizable ethylenically unsaturated monomer thereof are copolymerized. The obtained copolymer can be produced by various conventionally known polymerization methods, for example, a suspension polymerization method, a solution polymerization method, an emulsion polymerization method and the like.
As a method for graft-polymerizing a 2-oxazoline group-containing ethylenically unsaturated monomer onto a polymer main chain, various conventionally known graft polymerization methods can be used. The polymer to be graft-polymerized is not particularly limited. For example, one or more kinds selected from the group consisting of acrylic resin, polyester resin, polyether resin, polyamide resin, polyurethane resin and the like can be mentioned.

The number average molecular weight of the polymer compound having an oxazoline group is not particularly limited, but is, for example, 500 to 2,000,000, preferably 1,000 to 1,000,000, and more preferably 10,000. ~ 100,000.
Further, the oxazoline group equivalent (g solid / eq) of the polymer compound having an oxazoline group is 10 or more, preferably 50 or more, more preferably 100 or more, and 5000 or less from the viewpoint of storage stability and adhesiveness. It is preferably 2000 or less, more preferably 1000 or less, still more preferably 750 or less. The oxazoline group equivalent indicates the weight of the compound per oxazoline group, that is, the value obtained from the following formula.
Oxazoline cardinal equivalent = molecular weight / number of oxazoline groups per molecule

Examples of commercially available polymer compounds having a 2-oxazoline group at the side chain and / or the terminal of the polymer include the trade names "Epocross WS-300", "Epocross WS-500", and "Epocross WS-500" of Nippon Catalysis Co., Ltd. 2-Oxazoline group-containing polymer compound aqueous solution such as "Epocross WS-700", 2-oxazoline group such as "Epocross K-2010E", "Epocross K-2020E", "Epocross K-2030E", trade names of Nippon Catalyst Co., Ltd. One or more selected from the group consisting of an aqueous emulsion of a polymer compound contained therein can be mentioned.

The polyoxazoline compound is used, for example, in an aqueous solution, an organic solvent solution, an aqueous dispersion, a liquid, a molten state, or the like. In the present invention, it is preferable to use an aqueous solution or an aqueous dispersion from the viewpoint of environmental influence and compatibility with latex.

In the present invention, the polyoxazoline compound is preferably a polymer compound having a main chain consisting of a polymer having an acrylic skeleton, a polymer having a styrene-acrylic skeleton, or the like, and having a 2-oxazoline group at the side chain and / or the terminal. For example, the product names "Epocross WS-300", "Epocross WS-500", "Epocross WS-700", "Epocross K-2010E", "Epocross K-2020E", "Epocross K-2030E" of Nippon Shokubai Co., Ltd. It is preferable to use.

<Aqueous polymer dispersion>
As the aqueous polymer dispersion, what is generally called latex (L) can be used. The (L) is not particularly limited, and is, for example, vinylpyridine-styrene-butadiene copolymer rubber (VP-SBR) latex, styrene-butadiene copolymer rubber (SBR) latex, polybutadiene rubber (BR) latex, and chloroprene. Rubber (CR) latex, chlorosulfonated polyethylene rubber (CSM) latex, 2,3-dichlorobutadiene copolymer rubber (2,3-DCB) latex, nitrile butadiene rubber (NBR) latex, hydrogenated acrylonitrile butadiene methacrylate tri One or more selected from the group consisting of the original copolymer (X-NBR) latex and the like can be mentioned. Of these, vinyl pyridine-styrene-butadiene copolymer rubber (VP-SBR) is preferable.

<Contents of each component>
In the adhesive composition for adhering rubber and fiber, which comprises resorcin and / or a salt thereof, a polyoxazoline compound, and an aqueous polymer dispersion, the blending amount of each component is not particularly limited.
For example, the blending amount (solid content) of the polyoxazoline compound is 0.01 to 500 parts by mass, preferably 0.05 to 300 parts by mass, and more preferably 0.05 to 150 parts by mass with respect to 1 part by mass of resorcin. .. If the content of the polyoxazoline compound is less than 0.01 parts by mass, the adhesiveness may decrease. Further, when the content of the polyoxazoline compound exceeds 500 parts by mass, the adhesiveness to a specific rubber may decrease.
Further, for example, the blending amount (solid content) of the aqueous polymer dispersion is 0.1 to 100 parts by mass, preferably 0.5 to 50 parts by mass, more preferably 50 parts by mass with respect to 1 part by mass of the polyoxazoline compound (solid content). It is 1 to 30 parts by mass. If the blending amount of the aqueous polymer dispersion is less than 0.1 parts by mass, the adhesiveness may be deteriorated. Further, when the blending amount of the aqueous polymer dispersion exceeds 50 parts by mass, the heat adhesiveness may decrease.

An adhesive composition for adhering a rubber and a fiber, which comprises a polyoxazoline compound and an aqueous polymer dispersion, wherein the rubber contains a rubber containing an olefin compound having a carboxyl group. In the product, the blending amount of each component is not particularly limited.
For example, the blending amount (solid content) of the aqueous polymer dispersion is 0.1 to 100 parts by mass, preferably 0.5 to 50 parts by mass, and more preferably 1 to 1 part by mass with respect to 1 part by mass of the polyoxazoline compound (solid content). It is 30 parts by mass. If the blending amount of the aqueous polymer dispersion is less than 0.1 parts by mass, the adhesiveness may be deteriorated. Further, when the blending amount of the aqueous polymer dispersion exceeds 50 parts by mass, the heat adhesiveness may decrease.

<Other additives>
The adhesive composition of the present invention may contain one or more other additives that can be added to the adhesive composition, if necessary. Other additives include, for example, auxiliary agents, cross-linking agents, cross-linking aids / co-crosslinking agents, bulking agents, colorants, reinforcing agents, antioxidants, surfactants, softeners, plasticizers, compatibilizers, etc. One or more types selected from stabilizers, flame retardants, flame retardant aids, tackifiers and the like can be mentioned.

Examples of the auxiliary agent include one or more selected from metal soap, fatty acid amide and the like.
Examples of the cross-linking agent include one or more selected from sulfur, thiuram compounds, benzotriazole compounds, disulfide compounds, peroxides, polyols, polyisocyanates and the like. Of these, one or more selected from sulfur, peroxide and the like is preferable.
Examples of the cross-linking aid / co-cross-linking agent include a polyfunctional monomer (unsaturated carboxylic acid metal salt (for example, (meth) zinc acrylate, (meth) magnesium acrylate, etc.), a dimaleimide compound (phenylenedimaleimide, etc.), and a bird ( Examples thereof include meth) acrylate compounds (trimethylolpropane tri (meth) acrylate, etc.), triallyl compounds (triallyl isocyanurate, etc.), zinc oxide, polybutadiene, oximes, guanidines, and the like. Of these, one or more selected from unsaturated carboxylic acid metal salts, dimaleimide compounds, zinc oxide and the like is preferable.
Examples of the bulking agent / coloring agent / reinforcing material include one or more selected from carbon black, zinc oxide, silica, coloring pigments and the like.
Examples of the softener include paraffin-based process oils and the like.
The blending amount of each of these "other additives" can be any amount within a range that does not adversely affect the properties of the adhesive composition of the present invention. For example, with respect to 100 parts by mass of the adhesive composition, the blending amount of the cross-linking agent is 0.1 to 10.0 parts by mass, and the blending amount of the organic peroxide as the cross-linking agent is 0.5 to 8.0 mass by mass. The amount of the co-crosslinking agent can be adjusted to 0.5 to 15 parts by mass, and the amount of the softener of the surfactant can be adjusted to 1.5 to 50 parts by mass.

<Manufacturing method of adhesive composition>
The method for producing the adhesive composition is not particularly limited, and any method can be used as long as it is a known method for producing the adhesive composition.
For example, all the components can be put into a container and mixed by a device such as a mixer for production. Further, it may be produced by mixing some components and then blending the remaining components.

The method for producing an adhesive composition containing resorcin and / or a salt thereof, a polyoxazoline compound, and an aqueous polymer dispersion is not particularly limited, but for example, the resorcin is stirred in an aqueous solution or an aqueous dispersion of the polyoxazoline compound. After the initial condensate is formed by adding the mixture while stirring at room temperature, the mixture is mixed with an aqueous polymer dispersion (latex), water is added as necessary, and the mixture is stirred at room temperature. In addition, a salt of resorcin can be used in the same manner to obtain an adhesive composition containing a polyoxazoline compound and an aqueous polymer dispersion.
The method for producing the adhesive composition containing the polyoxazoline compound and the aqueous polymer dispersion is not particularly limited, and for example, an aqueous solution or an aqueous dispersion of the polyoxazoline compound is mixed with the aqueous polymer dispersion (latex). A method of adding water as needed and stirring at room temperature can be mentioned.
The solid content concentration of the adhesive composition of the present application is not particularly limited. For example, it can be 1 to 50% by mass, preferably 5 to 30% by mass, and more preferably 5 to 25% by mass.

<How to use the adhesive composition>
The adhesive composition is applied to the adhesive surface of the rubber and / or the fiber, and the two are brought into contact with each other, preferably pressurized and heated, so that the adhesive composition is used for adhering the rubber and the fiber.
The method of applying to rubber and / or fiber is not particularly limited, and a known method can be used.
In the present invention, it is preferable to apply the adhesive composition to the fibers by a one-bath type treatment method and a two-bath type treatment method.

In the case of the one-bath treatment method, each component is mixed to obtain an adhesive composition containing 5 to 25% by mass of the active ingredient, which is adhered to the fiber by a method such as dipping, spraying, or coating with a waste cloth and heat-treated. , A rubber product such as a belt can be formed by adhering it to rubber and heating and pressurizing it.
In the case of the two-bath treatment method, the fibers are treated in the first bath, heat-treated at 70 to 240 ° C. for 1 second to 10 minutes, then treated in the second bath, then heat-treated, adhered to rubber, and heated. It can be pressed to form a rubber product such as a belt.
The first and second baths include, for example.
(1) First bath: Resolcin and / or a salt thereof and an initial condensate of a polyoxazoline compound Second bath: Aqueous polymer dispersion (latex)
(2) First bath: Mixture of resorcin and / or a salt thereof and a polyoxazoline compound Second bath: Aqueous polymer dispersion (latex)
(3) First bath: resorcin and / or a salt thereof and an aqueous polymer dispersion (latex)
Second bath: Polyoxazoline compound (4) First bath: Aqueous polymer dispersion (latex)
Second bath: Polyoxazoline compound (5) First bath: Polyoxazoline compound Second bath: Aqueous polymer dispersion (latex)
And so on.

In the present invention, a method of immersing the fiber in the adhesive composition and a method of applying the adhesive composition to the fiber with a waste cloth or the like are preferable. The time for immersing the fiber in the adhesive composition can be 10 seconds or less, for example 0.5 to 5 seconds, and after the immersion, it can be treated at 150 to 270 ° C. for 15 to 600 seconds.
When the adhesive composition is attached to the fiber, the amount of the adhesive composition adhered is 0.01 to 10 parts by mass, preferably 0.1 to 8 parts by mass, and more preferably 0.5 to 5 parts by mass with respect to 1 m of the fiber. 6 parts by mass.

<Rubber>
The rubber bonded to the fiber by the adhesive composition of the present invention is not particularly limited as long as it is composed of a rubber composition containing a rubber component and a rubber compounding agent.
The rubber may be either vulcanized rubber or unvulcanized rubber. Vulcanized rubber is preferable because it has excellent adhesive strength to vulcanized rubber.

The rubber component of the rubber composition may be either synthetic rubber and / or natural rubber.
The synthetic rubber is a diene-based rubber having a carbon-carbon double bond in the polymer main chain, a non-diene-based rubber having no carbon-carbon double bond in the polymer main chain, or a modified product of these rubbers. The above can be used.

In the present invention, examples of the synthetic rubber include diene rubbers such as butadiene rubber (BR), styrene-butadiene rubber (SBR), acrylonitrile-butadiene rubber (NBR), chloroprene rubber (CR), and styrene-butadiene-styrene rubber. , Ethylene-propylene rubber (EPM), ethylene-propylene-diene rubber (EPDM), ethylene-propylene-dicyclopentadiene rubber, ethylene-propylene-ethylidene norbornene rubber (EPDM), ethylene-octene copolymer, ethylene-butene co-weight One or more types selected from olefin rubber such as coalesced rubber, silicone rubber, urethane rubber and the like can be mentioned. Further, modified products obtained by subjecting these rubbers to, for example, hydrogenation (hydrogenation) or modification by introducing various functional groups, for example, hydrogenated SBR, hydrogenated BR, hydrogenated acrylonitrile-butadiene rubber (hydrogenated acrylonitrile-butadiene rubber). One or more selected from H-NBR), chlorosulfonated polyethylene rubber (CSM) and the like can be used.

Examples of the rubber compounding agent include olefin compounds having a carboxyl group, reinforcing materials, oils, processing aids, vulcanization accelerator aids, cross-linking agents, co-crosslinking agents, vulcanization accelerators, antiaging agents and the like.
In particular, when an adhesive composition containing a polyoxazoline compound and an aqueous polymer dispersion and not containing resorcin is used to bond the rubber to the fiber, the rubber contains a rubber containing an olefin compound having a carboxyl group. It is necessary.

<Olefin compound having a carboxyl group>
In the present invention, examples of the olefin compound having a carboxyl group include a carboxylic acid having a (meth) acryloyloxy group, a carboxylic acid anhydride having a (meth) acryloyloxy group, and a carboxylic acid salt having a (meth) acryloyloxy group. And one or more selected from the group consisting of unsaturated fatty acids and the like.

Examples of the carboxylic acid compound having a (meth) acryloyloxy group include acrylic acid, methacrylic acid, maleic acid, citraconic acid, dimethylmaleic acid, 2-ethyl-3-methylmaleic acid, and 2-acryloyloxyethyl-succinic acid. Acid (light acrylate HOA-MS (N)), 2-acryloyloxyethyl hexahydrophthalic acid (light acrylate HOA-HH (N)), 2-acryloyloxyethyl-phthalic acid (light acrylate HOA-MPL (N)) )) And 2-Methacrylicyloxyethyl succinic acid (light ester HO-MS (N)) and the like, and one or more selected from the group.

Examples of the carboxylic acid compound anhydride having a (meth) acryloyloxy group include maleic anhydride, methacrylic anhydride, maleic anhydride, citraconic anhydride, maleic anhydride, 2-ethyl-3-methyl maleic anhydride, and the like. One or more types selected from the group consisting of the above can be mentioned.

Examples of the carboxylic acid compound salt having a (meth) acryloyloxy group include various metal salts of the carboxylic acid compound having a (meth) acryloyloxy group (for example, Li, Na, K, Mg, Ca, Zn, etc.) and the like. One or more types selected from the group consisting of.

Examples of unsaturated fatty acids include palmiterenic acid, petroseric acid, oleic acid, elaidic acid, lysynolic acid, linoleic acid, elaidic acid, linolenic acid, arachidonic acid, stearidonic acid, eicosapentaenoic acid, docosapentaenoic acid, and docosahexaenoic acid. , Docosatetraenoic acid, baxenoic acid, pauric acid, elaidic acid, nervonic acid, sapienoic acid and the like, and one or more selected from the group.
In addition, (2-methyl-2-propenyl) succinic acid, nonenyl succinic acid, 1-cyclohexene-1,2-dicarboxylic acid, 4-cyclohexene-1,2-dicarboxylic acid, dodecenyl succinic acid, octenyl succinic acid, 1-cyclohexene-1 , 2-Dicarboxylic acid anhydride, 4-cyclohexene-1,2-dicarboxylic acid anhydride, dodecenyl succinic acid anhydride, octenyl succinic acid anhydride, (2-methyl-2-propenyl) succinic acid anhydride, nonenenyl succinic acid anhydride and the like. One or more kinds selected from the group can be used.

In the present invention, one or more selected from the group consisting of a carboxylic acid having a (meth) acryloyloxy group, a carboxylic acid anhydride having a (meth) acryloyloxy group, an unsaturated fatty acid and a saturated fatty acid is preferable. For example, acrylic acid, methacrylic acid, maleic acid, maleic anhydride, 2-acryloyloxyethyl-succinic acid, 2-acryloyloxyethyl hexahydrophthalic acid, 2-acryloyloxyethyl-phthalic acid, 2-methacryloy. More preferably, one or more selected from the group consisting of roxyethyl succinic acid, acrylic acid metal salt, methacrylic acid metal salt and the like.

The blending amount of the olefin compound having a carboxyl group is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, and preferably 50 parts by mass or less with respect to 100 parts by mass of the rubber component of the rubber composition. , More preferably 20 parts by mass or less.
If the content of the olefin compound having a carboxyl group exceeds 50 parts by mass, or if it is less than 0.5 parts by mass, it may be difficult to form an adhesive composition layer, and the adhesive strength is lowered. There is a risk.

Examples of the reinforcing material include short fibers, for example, cellulose-based fine fibers, 6-nylon fibers, 6,6-nylon fibers, 4,6-nylon fibers, polyethylene terephthalate (PET) fibers, and polyethylene naphthalate (PEN). One or more kinds selected from the group consisting of fibers, para-aramid fibers, meta-aramid fibers, polyester fibers and the like can be mentioned.
The diameter of the staple fibers is preferably 1 μm or more, more preferably 5 μm or more, still more preferably 10 μm or more, and preferably 100 μm or less, more preferably 70 μm or less, still more preferably 50 μm or less.
The blending amount of the short fibers is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, and preferably 50 parts by mass or less, more preferably 40 parts by mass with respect to 100 parts by mass of the rubber component of the rubber composition. It is less than a part.

Examples of the reinforcing material include carbon black, channel black, furnace black (SAF, ISAF, N-339, HAF, N-351, MAF, FEF, SRF, GPF, ECF, N-234, etc.). , Thermal black (FT, MT, etc.), acetylene black, etc., and one or more selected from the group.
The blending amount of carbon black is preferably 1 part by mass or more, more preferably 5 parts by mass or more, and preferably 100 parts by mass or less, more preferably 50 parts by mass with respect to 100 parts by mass of the rubber component of the rubber composition. It is less than the mass part.

Examples of oils include petroleum-based softeners, mineral oils such as paraffin wax, castor oil, cottonseed oil, linseed oil, rapeseed oil, soybean oil, palm oil, palm oil, fallen raw oil, wood wax, rosin, and pine. One or more types selected from the group consisting of vegetable oils such as oils can be mentioned. The oil content is, for example, 1.5 to 50 parts by mass with respect to 100 parts by mass of the rubber component of the rubber composition.

Examples of the vulcanization accelerating aid include one or more selected from the group consisting of metal oxides such as zinc oxide (zinc oxide) and magnesium oxide, metal carbonates, fatty acids and derivatives thereof.
The content of the vulcanization accelerating aid is, for example, 5 to 15 parts by mass with respect to 100 parts by mass of the rubber component of the rubber composition.

Examples of the cross-linking agent include one or more selected from the group consisting of sulfur and organic peroxides. The organic peroxide is selected from the group consisting of, for example, dialkyl peroxides such as dicumyl peroxide, peroxy esters such as t-butyl peroxy acetate, and ketone peroxides such as dicyclohexanone peroxide. One or more types can be mentioned.
The blending amount of sulfur is, for example, 0.1 to 4.0 parts by mass with respect to 100 parts by mass of the rubber component of the rubber composition, and the blending amount of the organic peroxide is 100 parts by mass of the rubber component of the rubber composition. On the other hand, for example, it is 0.5 to 8.0 parts by mass.

As the co-crosslinking agent, for example, one kind selected from the group consisting of 1,2-polybutadiene, oximes, guanidine, (meth) acrylate compounds (TAIC, maleimides, trimethylolpropane trimethacrylate, acrylate, etc.) and the like. The above can be mentioned.
The content of the co-crosslinking agent is, for example, 0.5 to 40 parts by mass with respect to 100 parts by mass of the rubber component.

<Fiber>
The fibers to be adhered to the rubber by the adhesive composition of the present invention are not particularly limited.
It is composed of one or more types selected from the group consisting of single fibers, woven fabrics, knitted fabrics, non-woven fabrics, plyed yarns, nets, braids, braids, and combinations of one or more of these. In the present invention, a core wire composed of a single fiber and / or a twisted yarn, a cloth (for example, a canvas), and a non-woven fabric are preferably used.

Examples of the material constituting the fiber include polyamide fiber (6 nylon fiber, 66 nylon fiber, 46 nylon fiber, etc.), polyester fiber (polyethylene terephthalate (PET) fiber, polyethylene naphthalate (PEN) fiber, etc.), and aramid fiber (aramid fiber). Para-based aramid fiber, meta-based aramid fiber, etc.), vinylon fiber, glass fiber, carbon fiber, metal fiber (steel cord) and the like can be mentioned.

When the belt is constructed by using the adhesive structure of the present invention, it is preferable to use, for example, a core wire composed of twisted yarn or braid as the fiber layer. As the fiber constituting the twisted yarn, one or more kinds selected from the group consisting of polyamide fiber, polyester fiber, aramid fiber, vinylon fiber, glass fiber, carbon fiber, metal fiber and the like are used. The diameter of the core wire is, for example, 0.5 to 2.5 mm, and the dimension between the centers of the core wires adjacent to each other in the cross section of the belt is, for example, 0.05 to 0.20 mm.

[Adhesive structure]
The adhesive structure of the present invention includes one or more layers of a fiber layer, a layer of an adhesive composition, and a rubber layer, respectively.
The fiber layer constituting the adhesive structure is not particularly limited as long as it is a layer composed of fibers. For example, the above-mentioned adhesive composition of the present invention includes a layer composed of fibers to be adhered to rubber. When a plurality of fiber layers are included, each fiber layer may be the same or different.
As the layer of the adhesive composition constituting the adhesive structure, at least one layer of the adhesive composition layer for adhering the fiber layer and the rubber layer may be composed of the adhesive composition of the present invention.
The rubber layer constituting the adhesive structure is not particularly limited as long as it is a layer made of rubber. For example, the above-mentioned adhesive composition of the present invention includes a layer composed of a rubber composition to be adhered to fibers. When a plurality of rubber layers are included, each rubber layer may be the same or different.

Between the fiber layer and the layer of the adhesive composition, and between the layer of the adhesive composition and the layer of the rubber, if necessary, a primer layer containing an epoxy resin, an isocyanate resin, or the like, a primer layer, a base treatment layer, and rubber. Any intermediate layer such as a glue layer may be provided. In the present invention, since the adhesive composition has good adhesiveness, it can be directly laminated to form an adhesive structure without providing the intermediate layer.
Since the adhesive structure of the present invention is intended to be formalin-free, it is preferable that it does not contain a resorcin-formalin (-latex) layer (RF (L) layer). In some cases, the RF (L) layer may be provided on the fiber layer.

The adhesive structure of the present invention has at least a layer structure of a rubber layer / a layer of an adhesive composition / a fiber layer.
Further, the fiber layer may be embedded in the layer of the adhesive composition and have a structure of a rubber layer / an adhesive composition layer / a fiber layer / an adhesive composition layer / a rubber layer. .. Further, the fiber layer may be provided on the front surface of the adhesive structure or may be provided on a part thereof.
When the adhesive structure of the present invention has a plurality of fiber layers and / or rubber layers, each of these layers can be provided in any order. For example, the following layer structure can be used.
(1) Rubber layer A / Adhesive composition layer A / Fiber layer A / Adhesive composition layer B / Rubber layer B
(2) Rubber layer A / Adhesive composition layer A / Rubber layer B / Adhesive composition layer B / Fiber layer A / Adhesive composition layer C / Rubber layer C
(3) Rubber layer A / Adhesive composition layer A / Fiber layer A / Adhesive composition layer B / Rubber layer B / Adhesive composition layer C / Fiber layer B / Rubber layer C
Here, the rubber layers A to C, the adhesive composition layers A to C, and the fiber layers A to B may be the same or different. Further, the layers A to C of the adhesive composition may be one or more layers as long as it is the adhesive composition of the present invention.
Further, the fiber layer is embedded in the layer of the adhesive composition, and has a structure of, for example, a rubber layer A / an adhesive composition layer / a fiber layer / an adhesive composition layer / a rubber layer B. May be.

The thickness of each of the fiber layer, the adhesive composition layer, and the rubber layer constituting the adhesive structure of the present invention is not particularly limited and can be set to any thickness depending on the intended use and the like.
The layer thickness of the fiber layer can be, for example, 0.001 to 10.0 mm, preferably 0.01 to 3.0 mm.
The layer thickness of the adhesive composition can be, for example, 0.001 to 3.0 mm, preferably 0.01 to 1.0 mm.
The thickness of the rubber layer can be, for example, 0.01 to 500 mm, preferably 0.05 to 300 mm.

[belt]
The belt of the present invention includes the adhesive structure of the present invention and is wound around a pulley to transmit power. Any of a V-belt, a round belt, a toothed belt, a flat belt, and a V-ribbed belt may be used.
For example, the inner rubber layer constituting the pulley contact portion on the inner peripheral side of the belt, the adhesive composition layer (adhesive composition) of the present invention, the fiber layer, the adhesive composition layer, and the back rubber on the outer peripheral side of the belt. Layers are in this order. The fiber layer can be composed of, for example, a core wire provided with an adhesive composition so as to form a spiral having a pitch in the belt width direction. Further, a back reinforcing cloth may be provided instead of the back rubber layer.

The inner rubber layer and the back rubber layer are formed of a rubber composition in which an uncrosslinked rubber composition obtained by blending various rubber compounding agents with a rubber component and kneaded is heated and pressurized and crosslinked by a crosslinking agent. There is. The rubber compositions forming the compression rubber layer and the back rubber layer may be the same or different.

Examples of the rubber composition forming the inner surface rubber layer and the back surface rubber layer include the rubber component and the rubber compounding agent mentioned as constituting the adhesive structure of the present invention.
In the present invention, the rubber components forming the inner rubber layer and the back rubber layer can be the same.

Examples of the belt forming method include the following methods.
(I) A rubber sleeve is placed on a cylindrical drum having a smooth surface, and an uncrosslinked rubber sheet for a layer of back rubber and an uncrosslinked sheet for an adhesive composition are wound and laminated in this order on the outer periphery thereof. A fiber layer having a layer of an adhesive composition is spirally wound around a cylindrical inner mold, and an uncrosslinked rubber sheet for an adhesive composition and an uncrosslinked rubber sheet for an inner rubber layer are further wound from above. Are wound in order to form a laminated molded body.

(Ii) The rubber sleeve provided with the laminated molded body is removed from the cylindrical drum, the laminated molded body is set in the inner peripheral surface side of the outer mold, and then the inner mold is placed in the rubber sleeve set in the outer mold. Position and seal.

(Iii) The outer mold is heated, and high-pressure air or the like is injected into the sealed inside of the inner mold to pressurize the mold. The inner mold expands, and each uncrosslinked rubber sheet in the laminated molded body is compressed and penetrates into the molded surface of the outer mold, and the crosslinking of the uncrosslinked rubber sheets proceeds, and the fiber layer having the layer of the adhesive composition is compositely integrated. Finally, a cylindrical belt slab is molded. The molding temperature of the belt slab can be, for example, 100 to 180 ° C., the molding pressure can be, for example, 0.5 to 2.0 MPa, and the molding time can be, for example, 10 to 60 minutes.

(Iv) Depressurize the inside of the inner mold to release the seal, take out the belt slab molded through the rubber sleeve between the inner mold and the outer mold, cut the belt slab into a predetermined width, and turn it over. The belt is manufactured by.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. The present invention is not limited to the following examples. In the following, unless otherwise specified, "%" means "% by mass" and "part" means parts by mass.

[Adhesive composition]
<Example 1-1>
1.3 parts of resorcin, 15.5 parts of polyoxazoline compound, 100 parts of an aqueous polymer dispersion and 613.4 parts of water were mixed and stirred to prepare an adhesive composition A-1. In the obtained adhesive composition A-1, the molar ratio of resorcin (R) to the polyoxazoline compound (O) is R / O = 0.1, and the mass ratio of the latex (L) to the resorcin / polyoxazoline compound (RO). It was L / RO = 6.

<Examples 1-2 to 1-7; Comparative Example 1-1>
Each component was mixed and stirred with the composition shown in Table 1 to produce the adhesive compositions A-2-A-7 according to Examples 1-2 to 1-7. In the obtained adhesive composition A-2, the mass ratio of the latex (L) to the polyoxazoline compound (O) was L / O = 6.
Each component was mixed and stirred with the composition shown in Table 1 to produce the adhesive composition RFL according to Comparative Example 1-1.

Polyoxazoline compound 1: NIPPON SHOKUBAI, trade name "Epocross WS-300"
Polyoxazoline compound 2: Made by Nippon Shokubai Co., Ltd., trade name "Epocross WS-500"
Polyoxazoline compound 3: Made by Nippon Shokubai Co., Ltd., trade name "Epocross WS-700"
RF: 41.69 parts of water, 0.21 part of sodium hydroxide, 2.03 parts of resorcin, and 2.15 parts of formaldehyde were mixed, mixed and reacted to obtain an RF solution having a solid content weight of 3.04 parts. ..
Aqueous polymer dispersion: Styrene-butadiene-vinyl pyridine copolymerized latex (solid content 41.5 wt%)
The blending amounts of the polyoxazoline compounds 1 to 3, RF and the aqueous polymer dispersion in Table 1 are the solid content. The amount of water in Table 1 includes the amounts of polyoxazoline compounds 1 to 3 (Epocross WS-300, WS-500 or WS-700), RF and the respective amounts of water contained in the aqueous polymer dispersion. Is done.

[Adhesive structure]
<Preparation of rubber>
Each component was blended and kneaded to produce rubbers R-1 to R-5 having the compositions shown in Table 2.

<Preparation of core wire>
A polyethylene terephthalate cord (PET core wire) was prepared, and the PET core wire was fixed to the frame.
The adhesive composition is applied to the PET core wire by reciprocating the front and back of the PET core wire once with a waste cloth soaked in the adhesive composition A-1 to A-7, and dried at 195 ° C. for 1 minute, 230. It was baked at ° C for 1 minute.
The adhesive composition is applied to the PET core wire by reciprocating the front and back of the PET core wire with a waste cloth soaked with the adhesive compositions A-1 to A-7 once again. It was applied, dried at 195 ° C. for 1 minute, and baked at 230 ° C. for 1 minute.

<Examples 2-1 to 2-10, Comparative Examples 2-1 to 2-2>
The three treated PET core wires obtained were arranged at equal intervals, sandwiched between the rubbers shown in Table 3 or Table 4, and pressed at 160 ° C. for 45 minutes to prepare a test piece for an adhesive strength test.
Using the obtained test piece for adhesive strength test, the adhesive strength at room temperature, the adhesive strength at room temperature, the adhesive strength at 120 ° C., and the rubber attachment at 120 ° C. were measured. The results are also shown in Table 3 or Table 4.

The evaluation and measurement of various characteristics, etc. in the above Examples and Comparative Examples were performed as follows.

<Room temperature adhesive strength>
The test piece for the adhesive strength test was allowed to stand at room temperature (23 ° C.) for 24 hours or more. A peeling test was conducted by fixing the rubber part and three PET core wires coated with the adhesive composition, respectively, and separating the rubber part and the cord into upper and lower parts at a constant speed of 100 mm / min at 23 ° C. , Room temperature adhesive strength was measured.

<Heat adhesive strength>
The test piece for the adhesive strength test was allowed to stand in a constant temperature bath at the heating temperature shown in Table 3 or Table 4 for 30 minutes. Using a tensile tester, fix the rubber part and the three PET core wires coated with the adhesive composition, respectively, and attach the rubber part to the rubber part at a constant rate of 100 mm / min at the heating temperature shown in Table 3 or Table 4, respectively. A peeling test was carried out so that the cord was separated into upper and lower parts, and the heat adhesive force related to the heating temperature shown in Table 3 or Table 4 was measured.

Claims (5)

An adhesive composition for adhering rubber and fibers, which comprises resorcin and / or a salt thereof, a polyoxazoline compound, and an aqueous polymer dispersion. An adhesive composition for adhering a rubber and a fiber, which comprises a polyoxazoline compound and an aqueous polymer dispersion, wherein the rubber contains a rubber containing an olefin compound having a carboxyl group. thing. The adhesive composition according to claim 1 or 2, wherein the polyoxazoline compound is a polymer compound having two or more 2-oxazoline groups. An adhesive structure comprising a fiber layer, a layer of the adhesive composition according to any one of claims 1 to 3, and a rubber layer in this order. A belt comprising the adhesive structure according to claim 4.