JP4645815B2 - Adhesive composition - Google Patents

Description

  The present invention relates to an adhesive composition that can be suitably used for treating a fiber substrate as a rubber reinforcing material.

  Typical products using natural fibers, organic synthetic fibers, glass fibers and the like as reinforcing materials include natural rubber and synthetic rubber tires, diaphragms, and belts. Since these reinforcing materials have insufficient adhesion to natural rubber or synthetic rubber as they are, resorcin-formaldehyde resin (RF) and vinylpyridine copolymerized SBR (styrene-butadiene copolymer rubber) latex are usually used. It is used by impregnating with an adhesive composition (usually referred to as RFL solution) composed of synthetic rubber latex (L).

  On the other hand, highly saturated nitrile rubber (HNBR) obtained by hydrogenating NBR (acrylonitrile-butadiene copolymer rubber) is used as a conductive belt for automobiles by utilizing excellent properties such as heat resistance, oil resistance, and high strength. Used in the manufacture of toothed belts. In these applications, as in the case of using conventional synthetic rubber, the cords made by twisting the fibers impregnated with the above RFL solution, and the nonwoven fabrics and woven cloth-like materials made of the fibers are reinforced. Used as a material.

However, the adhesion between the fiber impregnated with the RFL liquid using a conventional synthetic rubber latex such as SBR, vinylpyridine copolymer SBR, NBR, and HNBR is not sufficient, and the rubber component of the RFL liquid is increased by use at a high temperature. There was a problem that the adhesive strength deteriorated due to deterioration. Therefore, an RFL solution using a nitrile group-containing copolymer rubber latex whose iodine value is reduced by hydrogenation instead of the conventional synthetic rubber latex has been studied (for example, see Patent Document 1).
JP 62-292430 A

  However, when a nitrile group-containing copolymer rubber latex having a reduced iodine value is used in the RFL solution, the fibers are easily loosened, the loose fibers are easily broken, and the entire core wire is cut, resulting in the fibers and rubber The problem of reducing the strength of the composite was observed. Then, when the cause of this problem was examined, it became clear that this problem arises because the adhesiveness and the softness | flexibility of the film formed in a fiber are inadequate.

  Accordingly, an object of the present invention is to provide an adhesive composition capable of forming an excellent adhesive film having good tackiness, flexibility and heat resistance on the surface of a fiber base material as a rubber reinforcing material. There is to do.

  As a result of intensive studies to solve the above problems, the present inventors have added a specific plasticizer to an adhesive composition containing a nitrile group-containing copolymer rubber latex having an iodine value of 120 or less and a resorcin-formaldehyde resin. It was found that this is effective in solving the above-mentioned problems, and the present invention was completed based on this finding.

That is, the present invention
[1] A plasticizer having 5 to 30 parts by weight of resorcin-formaldehyde resin (B) and a weight average molecular weight of 400 or more with respect to 100 parts by weight of the rubber component of the nitrile group-containing copolymer rubber latex (A) having an iodine value of 120 or less. An adhesive composition comprising 3 to 50 parts by weight of (C),
[2] A fiber member obtained by impregnating at least a part of a fiber base material with the adhesive composition according to [1], and [3] a vulcanized rubber reinforced with the fiber member according to [2]. A composite consisting of members,
Is to provide.

  According to the present invention, an adhesive composition capable of forming an excellent adhesive film having good tackiness, flexibility and heat resistance on the surface of a fiber base material as a rubber reinforcing material is obtained. The adhesive composition of the present invention is particularly excellent in the adhesion between the fiber base material and HNBR.

  The adhesive composition of the present invention may be referred to as a nitrile group-containing copolymer rubber latex (A) having an iodine value of 120 or less [hereinafter referred to as rubber latex (A). ] For 100 parts by weight of the rubber component of resorcinol-formaldehyde resin (B) [hereinafter sometimes referred to as resin (B). And 5 to 30 parts by weight of a plasticizer (C) having a weight average molecular weight of 400 or more.

  The adhesive composition of the present invention is characterized in that it contains the plasticizer (C).

  If a plasticizer is added to the conventionally used RFL liquid, the stickiness of the liquid increases and the strength of the coating formed by the liquid decreases. Therefore, there was no merit of adding a plasticizer to the RFL liquid. However, when the cause of the problem was first clarified when a nitrile group-containing copolymer rubber latex having a reduced iodine value was used for the RFL solution, and various studies were conducted based on the findings, it was identified as such an RFL solution. Surprisingly, the adhesiveness and flexibility of the coating could be improved by adding this plasticizer, and the strength of the composite could be made sufficient.

  In addition, each structural component of this invention may be used independently suitably, or may use 2 or more types together.

  In the present specification, the terms “coating” and “coating” have the same meaning. The term “vulcanized” is used in its usual meaning in the rubber industry and is not limited to sulfur crosslinking. Moreover, when referring to content of a structural component, the amount of the said component itself is said.

  The nitrile group-containing copolymer rubber latex of the present invention is not particularly limited as long as it is a latex of a rubber having a nitrile group. For example, a monomer having a nitrile group, preferably an α, β-ethylenically unsaturated nitrile monomer. Examples thereof include rubber latex obtained by copolymerizing a monomer and another monomer copolymerizable with the monomer.

  In the present invention, a rubber latex (A) having an iodine value of 120 or less is used. However, if the iodine value exceeds 120, the heat resistance of the coating is impaired, which is not preferable. The iodine value is preferably 100 or less, more preferably 50 or less, from the viewpoint of improving heat resistance. In the present specification, the iodine value of the rubber latex refers to the iodine value of the rubber component contained in the latex. The iodine value can be measured, for example, according to JIS K 6235 using a rubber obtained by coagulating latex with a coagulant and then drying it.

  The production method of the rubber latex (A) of the present invention is not particularly limited, and for example, by emulsion polymerization of an α, β-ethylenically unsaturated nitrile monomer and another monomer, or α, β- It can be produced by latexing a solution of a nitrile group-containing copolymer rubber obtained by solution polymerization of an ethylenically unsaturated nitrile monomer and another monomer by a phase inversion method or the like.

  When the iodine value of the rubber latex (A) obtained as described above exceeds 120, the iodine value may be reduced by hydrogenating the rubber according to a known method. The hydrogenation method is not particularly limited. For example, a method of hydrogenating rubber in a latex state, a method of hydrogenating rubber before latex, for example, a nitrile group-containing copolymer rubber obtained by solution polymerization An example is a method in which the solution is hydrogenated as it is and latexed by a phase inversion method or the like. Examples of the hydrogenation method in the latex state include a method using a palladium compound as a hydrogenation catalyst (JP-A-2-178305, JP-A-3-167239, etc.), and a method using hydrazine and a peroxide. (Japanese Patent Laid-Open Nos. 59-161415, 4-505176, etc.).

  Examples of the α, β-ethylenically unsaturated nitrile monomer include acrylonitrile, methacrylonitrile, α-chloroacrylonitrile and the like, and acrylonitrile and methacrylonitrile are preferable.

  The content of the α, β-ethylenically unsaturated nitrile monomer unit in the rubber component of the rubber latex (A) is preferably 5 to 60% by weight, more preferably 7 to 50% by weight, particularly preferably 10 to 10% by weight. 40% by weight. 5% by weight or more is desirable from the viewpoint of ensuring good oil resistance of the coating film, and 60% by weight or less is desirable from the viewpoint of securing cold resistance and adhesiveness of the favorable coating film.

  Other monomers to be copolymerized with the α, β-ethylenically unsaturated nitrile monomer include conjugated diene monomers; non-conjugated diene monomers; α-olefins; Fluorine-containing vinyl monomer; α, β-ethylenically unsaturated monocarboxylic acid and its ester; α, β-ethylenically unsaturated polycarboxylic acid, its monoester, polyvalent ester and anhydride; Examples thereof include a polymerizable antioxidant.

  Examples of the conjugated diene monomer include 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, and 1,3-butadiene and isoprene are preferable. .

  As the non-conjugated diene monomer, those having 5 to 12 carbon atoms are preferable, and examples thereof include 1,4-pentadiene, 1,4-hexadiene, vinylnorbornene, and dicyclopentadiene.

  The α-olefin preferably has 2 to 12 carbon atoms, and examples thereof include ethylene, propylene, 1-butene, 4-methyl-1-pentene, 1-hexene, 1-octene and the like.

  Examples of the aromatic vinyl monomer include styrene, α-methylstyrene, vinyl pyridine, and the like.

  Examples of the fluorine-containing vinyl monomer include fluoroethyl vinyl ether, fluoropropyl vinyl ether, o-trifluoromethyl styrene, vinyl pentafluorobenzoate, difluoroethylene, and tetrafluoroethylene.

  Examples of the α, β-ethylenically unsaturated monocarboxylic acid include acrylic acid and methacrylic acid. Examples of the α, β-ethylenically unsaturated monocarboxylic acid ester include ethyl (meth) acrylate, butyl (meth) acrylate, and 2-ethylhexyl (meth) acrylate. In the present specification, “(meth) acryl” means “acryl” or “methacryl”.

  Examples of the α, β-ethylenically unsaturated polyvalent carboxylic acid include itaconic acid, fumaric acid, maleic acid and the like. Examples of the α, β-ethylenically unsaturated polycarboxylic acid monoester include monomethyl itaconate, monoethyl itaconate, monobutyl itaconate, monomethyl fumarate, monoethyl fumarate, monobutyl fumarate, monomethyl maleate, monoethyl maleate And monobutyl maleate. Examples of the α, β-ethylenically unsaturated polycarboxylic acid polyvalent ester include dimethyl itaconate, di-2-ethylhexyl itaconate, di-n-butyl fumarate, dimethyl maleate and the like. Examples of the α, β-ethylenically unsaturated polyvalent carboxylic acid anhydride include itaconic anhydride and maleic anhydride.

  Examples of copolymerizable anti-aging agents include N- (4-anilinophenyl) acrylamide, N- (4-anilinophenyl) methacrylamide, N- (4-anilinophenyl) cinnamamide, N- (4 -Anilinophenyl) crotonamide, N-phenyl-4- (3-vinylbenzyloxy) aniline, N-phenyl-4- (4-vinylbenzyloxy) aniline and the like.

  In addition, when the rubber component of the rubber latex (A) of the present invention contains a carboxyl group, the carboxylic acid equivalent is preferably 0.5 ephr or less, more preferably from the viewpoint of improving the adhesion and cold resistance of the film. It is 0.1 ephr or less. The carboxylic acid equivalent can be measured, for example, by the method described in JP-A-2004-250645 using a rubber obtained by coagulating latex with a coagulant and then drying it.

The Mooney viscosity ML _{1 + 4} (100 ° C.) of the rubber component of the rubber latex (A) of the present invention is not particularly limited, but is preferably in the range of 10 to 250 from the viewpoint of improving the strength of the film. The Mooney viscosity can be measured, for example, according to JIS K 6300 using a rubber obtained by coagulating latex with a coagulant and then drying it.

  The average particle diameter of the particles made of the rubber component of the rubber latex (A) is not particularly limited, but is preferably about 80 to 300 nm from the viewpoint of sufficiently impregnating the fiber base material with the latex. The average particle diameter can be measured using, for example, a light scattering diffraction particle diameter measuring apparatus.

  The content of the rubber component in the rubber latex (A) is not particularly limited, but preferably 1 to 80% by weight, more preferably 10 to 60% by weight, considering a good balance between latex stability and workability. Particularly preferred is 20 to 50% by weight.

  An emulsifier is used for the preparation of the rubber latex (A), but the emulsifier is not particularly limited. For example, the emulsifier is usually used for producing a nitrile group-containing unsaturated copolymer rubber by emulsion polymerization and its latex. An emulsifier such as an anionic emulsifier or a nonionic emulsifier may be used.

  Examples of the anionic emulsifier include potassium salts and sodium salts such as fatty acids, rosin acids, alkylbenzene sulfonic acids, and alkyl sulfates. Specifically, examples of the anionic emulsifier include potassium oleate, sodium stearate, potassium rosinate, sodium dodecylbenzenesulfonate, sodium linear alkylbenzenesulfonate, sodium lauryl sulfate and the like.

  Nonionic emulsifiers include polyoxyethylene, polyoxyethylene-polyoxypropylene block copolymers and other polyoxyalkylenes, polyoxyethylene alkyl ethers in which higher oxides such as dodecanol and hexadecanol are added with ethylene oxide. Can be mentioned.

  The content of the emulsifier in the rubber latex (A) is not particularly limited, and is usually 1 from 100 parts by weight of the rubber component in the rubber latex (A) from the viewpoint of maintaining good hygroscopicity and adhesiveness of the film. About 15 parts by weight is preferable.

  The resin (B) used in the present invention is not particularly limited, and any resorcin-formaldehyde resin conventionally used in an RFL solution can be used. For example, resorcin is dissolved in water, mixed with an aqueous formaldehyde solution and reacted with an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide as a catalyst; or under an acidic catalyst such as oxalic acid or hydrochloric acid. Any of the reacted novolac resins may be used. When a novolac-type resorcin-formaldehyde resin is used, the resin is added to water to which a small amount of sodium hydroxide or aqueous ammonia is added to make an aqueous solution. When a novolac type resorcin-formaldehyde resin is used, an aqueous formaldehyde solution may be further added if desired.

  Resin (B) is usually a water-soluble initial condensate obtained by reacting formaldehyde with 1 to 3 moles, preferably 1.2 to 2 moles per mole of resorcin, and used as an aqueous solution. Is done. The degree of condensation of the resin (B) may not be complete, and what is considered a precursor of a so-called initial condensate can also be used as the resin (B).

  Content of resin (B) is 5-30 weight part with respect to 100 weight part of rubber components of rubber latex (A) in the adhesive composition of this invention, Preferably it is 7-25 weight part. When the content of the resin (B) is less than 5 parts by weight, the adhesion between the fiber base material and the rubber is not sufficient. On the other hand, when the content exceeds 30 parts by weight, the film becomes too hard and the adhesiveness of the film decreases. Since the flexibility of a fiber base material is impaired, it is not preferable. When the content is in the preferred range, the adhesiveness, tackiness and flexibility of the coating are good.

  The kind of the plasticizer (C) used in the present invention is not particularly limited, and the weight average molecular weight is 400 or more, preferably 430 to 5000, more preferably 500 to 1000. When the weight average molecular weight is less than 400, the coating film has a large hardness and is inferior in adhesiveness. On the other hand, if the weight average molecular weight is in the above preferred range, the tackiness is good and the adhesion between the fiber substrate and the rubber is also good, which is desirable.

  The weight average molecular weight in the present specification can be measured, for example, by a gel permeation chromatography (GPC) method using monodispersed polystyrene as a standard sample.

  Moreover, as a plasticizer (C), the solubility parameter (SP value by the HOY method) is 8.3 to 9.5 in order to make the compatibility with the rubber component in the latex better. Is more preferable, and it is more preferable that it is 8.5-9.3. Examples of such a plasticizer include phthalate esters such as diisononyl phthalate (weight average molecular weight 419, SP value 8.5) and diisodecyl phthalate (weight average molecular weight 447, SP value 8.5); tri- (2- Ethylhexyl) trimellitate (weight average molecular weight 547, SP value 8.9), tri-n-octyl trimellitate (weight average molecular weight 547, SP value 8.9), triisononyl trimellitate (weight average molecular weight 630, SP) Trimellitic acid ester such as value 8.8); Adipic acid ester such as dibutoxyethoxyethyl adipate (weight average molecular weight 434, SP value 9.2); Phthalic acid polyester; Adipic acid polyether ester; Adipic acid Examples thereof include polyester plasticizers such as polyester.

  Content of a plasticizer (C) is 3-50 weight part with respect to 100 weight part of rubber components of rubber latex (A) in the adhesive composition of this invention, Preferably it is 5-40 weight part. When the content of the plasticizer (C) is less than 3 parts by weight, the film is inferior in flexibility and tackiness. On the other hand, when it exceeds 50 parts by weight, the film adhesion is inferior. When the content is in the preferred range, the adhesiveness, tackiness and flexibility of the coating are good.

  In addition to the above components, the adhesive composition of the present invention includes other compounds such as phenol compounds, halogenated phenol compounds, isocyanate compounds, blocked isocyanate compounds, ethylene urea compounds, polyepoxy compounds, and modified polyvinyl chloride resins. Ingredients may be included.

  The total content of the rubber component of the rubber latex (A), the resin (B), and the plasticizer (C) (hereinafter referred to as component content) of the adhesive composition of the present invention is as follows. Considering a good balance between the adhesion amount and the adhesiveness, it is preferably 5 to 50% by weight.

  The adhesive composition of the present invention is produced, for example, by appropriately mixing rubber latex (A), an aqueous solution of resin (B), a plasticizer (C), and optionally other components according to known methods.

  The order of addition of the plasticizer (C) is not particularly limited. Even if the mixture is prepared after preparing a mixed solution of the rubber latex (A) and the aqueous solution of the resin (B), the rubber latex (A) and / or the resin ( You may add to the aqueous solution of B). The plasticizer (C) may be added as it is, but in consideration of the stability of the rubber latex (A) and the mixed solution, an emulsion obtained by previously mixing an emulsifier and water with the plasticizer (C). It is preferable to add as.

  Although the use of the adhesive composition of the present invention is not particularly limited, for example, it is suitably used as an RFL liquid for adhesion between a fiber substrate and HNBR.

  The fiber member of the present invention is obtained by impregnating at least a part of a fiber base material with the adhesive composition of the present invention. Here, “impregnation” is to include an adhesive composition in a fiber base material, and there is no particular limitation on the mode thereof. For example, an adhesive composition containing an arbitrary solvent is used as a fiber base material. The embodiment (embodiment 1) to be included in the embodiment, or the embodiment in which the adhesive composition not containing the solvent is contained in the fiber base, that is, the solvent is removed and dried in the embodiment 1, and other than the solvent of the adhesive composition. An embodiment (embodiment 2) in which only the component is included in the fiber base material is included. Since the versatility is high, the fiber member of the present invention is preferably one in which the fiber base material is impregnated with the adhesive composition according to aspect 2.

  The fiber substrate is not particularly limited, and examples thereof include polyamide fibers such as vinylon fibers, polyester fibers, nylon fibers, and aramid (aromatic polyamide) fibers, cotton, rayon, carbon fibers, and glass fibers. For example, it is used in the form of woven fabrics such as staples, filaments, cords, ropes, canvases, and non-woven fabrics. As the fiber base material, nylon fiber, aramid fiber, carbon fiber, and glass fiber are preferable from the viewpoint of preventing loosening of bundling and preventing a decrease in strength of the composite of the fiber base material and rubber.

  The method for impregnating at least a part of the fiber base material with the adhesive composition of the present invention is not particularly limited, and a known method may be followed. For example, the adhesion amount of the adhesive composition (components other than the solvent) after drying on the fiber base material is preferably about 5 to 40 parts by weight with respect to 100 parts by weight of the fiber base material. What is necessary is just to impregnate an adhesive composition. The impregnation is preferably carried out uniformly over the entire fiber substrate. When drying the solvent of the adhesive composition, the heating is preferably performed at 100 to 250 ° C. for several minutes. The fiber member of the present invention may further contain an overcoat agent containing rubber or resin.

  Although the use of the fiber member of the present invention is not particularly limited, for example, it is suitably used as a reinforcing material for rubber belts for automobiles using HNBR as rubber.

  The composite of the present invention comprises a vulcanized rubber member reinforced with the fiber member of the present invention. In a composite, both members are usually in a bonded state. However, if the reinforcing effect of the fiber member is exerted on the vulcanized rubber member, it is not always necessary that all the members are in a bonded state. . Since the composite of the present invention is formed by adhering a fiber base material and a vulcanized rubber member with the adhesive composition of the present invention, it depends on the properties of the vulcanized rubber member, but particularly at high temperatures (for example, , About 130 ° C.), it has an excellent strength equal to or higher than that of a conventional similar composite.

  The vulcanized rubber member is, for example, a rubber component such as acrylonitrile-butadiene copolymer, carboxyl group-containing acrylonitrile-butadiene copolymer, acrylonitrile-isoprene-butadiene copolymer, and hydrides thereof, preferably the hydride; sulfur It is obtained by vulcanizing by heating a vulcanizable rubber composition prepared by appropriately mixing a vulcanizing agent such as a vulcanizing agent and a peroxide vulcanizing agent; and a vulcanization accelerator according to a known method. is there.

  In the vulcanizable rubber composition, reinforcing agents such as carbon black and short fibers, fillers such as silica, anti-aging agents, plasticizers, pigments, and adhesives, which are usually blended during rubber processing, in addition to the above-mentioned blends A compounding agent such as an imparting agent, a processing aid, a scorch inhibitor, a co-crosslinking agent, or the like can be appropriately added.

  The method for producing the composite of the present invention is not particularly limited. For example, according to a known method, the fiber member of the present invention and the vulcanizable rubber composition as described above can be mixed and molded and then heated, or heated simultaneously with the molding. In addition, the composite can be produced by superimposing the fiber member of the present invention and the vulcanizable rubber composition and molding simultaneously with heating.

  Specifically, as a method for producing the composite of the present invention, for example, a method of spreading the fiber member of the present invention and the vulcanizable rubber composition as described above, and then pressurizing and heating is adopted. Is preferred. The rubber compound can be spread and pressed using a compression (press) molding machine, a metal roll, an injection molding machine or the like. It is preferable to form a mold that realizes a desired surface shape of the target rubber fiber composite on the inner surface of the mold of the compressor and the surface of the roll.

  The pressure at the time of pressurization is preferably 0.1 to 20 MPa, more preferably 1 to 10 MPa.

  The heating temperature is preferably 130 to 300 ° C, more preferably 150 to 250 ° C. If the heating temperature is within such a suitable range, the vulcanization time and vulcanization density are appropriate, and molding can be carried out satisfactorily. The heating time is preferably 1 minute to 24 hours, more preferably 5 minutes to 4 hours, considering the balance between the vulcanization density and production efficiency.

  Depending on the shape and size of the vulcanizate, the surface may be vulcanized but the interior may not be vulcanized. In such a case, secondary vulcanization may be performed after heating as described above and maintaining a high temperature state.

  By the above method, vulcanization and molding of the vulcanizable rubber composition, and adhesion of the fiber member and the vulcanized rubber member made of the vulcanized rubber composition can be performed simultaneously.

  Examples of the composite obtained as described above include industrial products such as seals, rubber belts, rubber rolls, rubber hoses, and parts thereof, and rubber members used in oil wells, gas wells, and the like. Examples of the seal include an oil seal, a piston seal, a mechanical seal, an O-ring, a mental regent seal, and various gaskets. Examples of the rubber belt include a flat belt, a V belt, a V-ribbed belt, a round belt, a square belt, and a toothed belt. Examples of the rubber roll include rolls that are parts of OA equipment such as printing equipment and copying equipment, spinning rolls for spinning, fiber processing rolls such as drafting rolls for spinning, and iron-making rolls such as bridle rolls, snubber rolls, and steering rolls. Examples of the rubber hose include a braided reinforcement hose and a cloth-wrapped reinforcement hose.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited only to this Example. In the text, “parts” and “%” are based on weight unless otherwise specified.

Reference Example 1 Preparation of nitrile group-containing copolymer rubber latex In a pressure-resistant bottle with an internal volume of 1 liter, 240 ml of water, 4 g of potassium oleate, and 37 g of acrylonitrile were placed in this order. Press-fitted. Polymerization was performed by adding 0.25 g of ammonium persulfate as a polymerization initiator to obtain an acrylonitrile-butadiene copolymer rubber (NBR) latex. Next, 400 milliliters of NBR latex adjusted to a rubber component content of 12% was put into a 1 liter autoclave equipped with a stirrer, and nitrogen gas was passed for 10 minutes to remove dissolved oxygen in the latex, followed by hydrogenation. The catalyst was added. After the inside of the reaction system was replaced with hydrogen gas twice, hydrogen gas was pressurized to 3 MPa, and the contents were heated to 50 ° C. and reacted for 6 hours. Then, after removing acetone using an evaporator, it concentrated until the content of the rubber component became about 40% to obtain an HNBR latex (A-1) having an iodine value of 28.

  Furthermore, 37 g of acrylonitrile was changed to 35 g of acrylonitrile and 2 g of methacrylic acid, the hydrogenation conditions were changed, and the HNBR latex (A-2) containing a carboxyl group was changed to HNBR by changing the ratio of acrylonitrile and butadiene and the hydrogenation conditions. The latex (A-3) and the acrylonitrile-butadiene copolymer rubber (NBR) latex before hydrogenation of the latex (A-1) were concentrated to obtain an NBR latex (A-4).

  Table 1 shows the acrylonitrile (AN) unit content (bound AN amount), carboxylic acid equivalent, iodine value, Mooney viscosity, average particle diameter, and content of the rubber component in each latex and the pH of each latex. .

  The amount of bonded AN was measured by a semi-micro Kjeldahl method using rubber obtained by coagulating 100 g of latex with 1 liter of methanol and then vacuum drying at 60 ° C. for 24 hours.

  Carboxylic acid equivalent was obtained by dissolving the obtained rubber in acetone and reprecipitating with n-hexane for purification, and then redissolving the obtained rubber in pyridine (special grade of JIS K 8777). Was titrated with 0.02N potassium hydroxide in ethanol using thymolphthalein as an indicator to obtain a titration amount A (ml). On the other hand, the same operation was carried out with pyridine alone (no rubber sample). The value B (ml) was obtained and determined as the number of acid equivalents by the formula [(AB) × 0.02 × 100] / [1000 × M]. In the calculation formula, M represents the rubber amount (g). The obtained acid equivalent number is the equivalent number of carboxyl groups with respect to 100 grams of rubber, and the unit is ephr.

  The iodine value was measured according to JIS K 6235 using the rubber obtained in the same manner.

  Mooney viscosity was measured according to JIS K 6300 using the rubber obtained in the same manner.

  The average particle size was measured with latex using a light scattering diffraction particle size measuring device (LS-230: manufactured by Coulter).

Reference Example 2 Preparation of Resorcin-Formaldehyde Resin Aqueous Solution Each component was mixed according to the formulation shown in Table 2 and aged at 25 ° C. for 6 hours to obtain an aqueous solution of resorcin-formaldehyde resin (resin content 6.5%).

Reference Example 3 Preparation of Plasticizer Emulsion According to the formulation shown in Table 3, a plasticizer emulsion having a content of 50% was prepared. In addition, tri- (2-ethylhexyl) trimellitate (weight average molecular weight 547, SP value 8.9) is used as the plasticizer 1, and di- (2-ethylhexyl) phthalate (molecular weight 391, SP value 9.0) is used as the plasticizer 2. Was used. Further, a 25% aqueous solution of potassium rosinate (P-1, manufactured by Toho Chemical Co., Ltd.) was used as an emulsifier.

Reference Example 4 Preparation of Wearable Rubber Composition According to the formulation shown in Table 4, HNBR [Zetpol 2010H, manufactured by Nippon Zeon Co., Ltd .: 36% bonded AN, iodine value 11, Mooney viscosity ML _{1 + 4} (100 ° C.) 120] and other formulations The rubber composition was kneaded with a roll to prepare a rubber composition to be worn.

  In the table, “SRF carbon black” is “Seast S” manufactured by Tokai Carbon Co., Ltd., and “Zinc Hana 1” is manufactured by Shodo Chemical Co., Ltd., and “1,3-bis (t-butylperoxyisopropyl) benzene” The “40% product” is “Vul-Cup40KE” (manufactured by GEO Specialty Chemicals Inc.).

Example 1
In accordance with the formulation shown in Table 5, latex A-1, an aqueous solution of resorcin-formaldehyde resin and water were mixed to obtain a mixture (total content of rubber component and resin of 20%). To the mixture, an emulsion of plasticizer 1 was added and mixed to prepare an adhesive composition (RFL solution). In Table 5, the numbers in parentheses in the blending amount of the aqueous solution of resorcin-formaldehyde resin and the emulsion of the plasticizer are the number of parts of the resin and the plasticizer with respect to 100 parts of the rubber component of the rubber latex, respectively.

Example 2
An adhesive composition (RFL solution) was prepared in the same manner as in Example 1 except that the amount of the plasticizer 1 emulsion was changed from 20 parts to 40 parts.

Example 3
An adhesive composition (RFL solution) was prepared in the same manner as in Example 2 except that latex A-2 was used instead of latex A-1.

Example 4
An adhesive composition (RFL solution) was prepared in the same manner as in Example 2 except that latex A-3 was used instead of latex A-1.

Example 5
An adhesive composition (RFL solution) was prepared in the same manner as in Example 2 except that the aqueous solution of resorcin-formaldehyde resin was changed from 154 parts to 308 parts and water was changed from 145 parts to 40 parts.

Comparative Example 1
An adhesive composition (RFL liquid) was prepared in the same manner as in Example 1 except that the plasticizer 1 emulsion was not used.

Comparative Example 2
An adhesive composition (RFL liquid) was prepared in the same manner as in Example 1 except that the amount of the plasticizer 1 emulsion was changed from 20 parts to 140 parts.

Comparative Example 3
An adhesive composition (RFL liquid) was prepared in the same manner as in Example 1 except that the plasticizer 1 emulsion was changed to the plasticizer 2 emulsion.

Comparative Example 4
An adhesive composition (RFL solution) was prepared in the same manner as in Example 1 except that the aqueous solution of resorcin-formaldehyde resin was changed from 154 parts to 31 parts and water was changed from 145 parts to 230 parts.

Comparative Example 5
An adhesive composition (RFL solution) was prepared in the same manner as in Example 1, except that the aqueous solution of resorcin-formaldehyde resin was changed from 154 parts to 615 parts and water was changed from 145 parts to 0 parts.

Comparative Example 6
An adhesive composition (RFL solution) was prepared in the same manner as in Example 1 except that latex A-4 was used instead of latex A-1.

Comparative Example 7
A modified SBR latex (Nipol 2518FS, manufactured by Nippon Zeon Co., Ltd .; containing vinylpyridine copolymerized SBR as a solid content and a rubber component content of latex of 40%) is used instead of Latec A-1, and an emulsion of plasticizer 1 is used. An adhesive composition (RFL solution) was prepared in the same manner as in Example 1 except that there was no.

Examples 6-10, Comparative Examples 8-14
A base fabric made of nylon 66 was dipped in the adhesive compositions of Examples 1 to 5 and Comparative Examples 1 to 7, respectively, heated at 180 ° C. for 2 minutes, impregnated with the adhesive composition, and dried. A base fabric made of reinforced nylon 66 was obtained. In addition, the adhesion amount in the base fabric of an adhesive composition was about 20 parts with respect to 100 parts of base fabrics.

Examples 11-15, Comparative Examples 15-21
Each of the base fabrics of Examples 6 to 10 and Comparative Examples 8 to 14 was overlaid on the rubber composition to be worn of Reference Example 4, and vulcanized at a press pressure of 5 MPa and 170 ° C. for 15 minutes to give a 15 cm × 15 cm square nylon base. A composite of cloth and rubber was obtained.

Test example 1
Each of the adhesive compositions obtained in Examples 1 to 5 and Comparative Examples 1 to 7 was applied on a glass plate, dried at 20 ° C. for 4 days, and then heat-treated at 160 ° C. for 60 minutes to obtain a thickness. A coating film of 0.5 mm adhesive composition was prepared. Using the obtained coating film, a dumbbell-shaped No. 7 test piece was produced according to JIS K 6251. Subsequently, the following physical property measurement was performed using this test piece. Each measurement was performed three times, and the average value was obtained. The results are also shown in Table 5.

  Adhesion to the glass plate (humidity 50% RH, 23 ° C.) was measured using a tell tack meter (see Japanese Patent Publication No. 47-12830, Monsanto, TT-1 type).

  The elongation at break (elongation) was measured according to JIS K 6251, and the hardness was measured according to a micro-size international rubber hardness test of JIS K 6253, respectively.

  Moreover, after maintaining at 120 degreeC for 168 hours according to the normal oven method of JISK6257, elongation was measured and the elongation change rate before and behind maintaining at 120 degreeC was calculated | required.

Test example 2
For the composites of Examples 11 to 15 and Comparative Examples 15 to 21, the peel strengths of rubber and nylon base fabric were measured according to JIS K 6256. The said peeling strength shows the adhesiveness of the coating film of adhesive composition. Each measurement was performed three times, and the average value was obtained. The results are also shown in Table 5.

  In addition, in the table | surface, the result about the composite_body | complex of Examples 11-15 and Comparative Examples 15-21 is described as a result about the adhesive composition of the corresponding Examples 1-5 and Comparative Examples 1-7, respectively.

  From the results of Test Examples 1 and 2 shown in Table 5, the following can be understood. The coating film of the adhesive composition that does not contain a plasticizer is large in hardness and inferior in tackiness (Comparative Example 1). When the amount of the plasticizer is larger than the range of the present invention, the tackiness is small and the adhesiveness is also small (Comparative Example 2). In Comparative Example 2, bleeding of the plasticizer occurred during the measurement of hardness. When the molecular weight of the plasticizer is smaller than the range of the present invention, the hardness is large and the adhesiveness is poor (Comparative Example 3). If the amount of resorcin-formaldehyde resin is less than the range of the present invention, the adhesiveness is poor (Comparative Example 4). When the amount of the resorcin-formaldehyde resin is larger than the range of the present invention, the hardness is large and the tackiness is inferior (Comparative Example 5). If the iodine value of the rubber latex is larger than the range of the present invention, the heat resistance is poor (Comparative Example 6). When modified SBR latex is used as the rubber latex, it is inferior in heat resistance and adhesiveness (Comparative Example 7). On the other hand, the coating film of the adhesive composition of any example is excellent in tackiness, flexibility, heat resistance, and adhesiveness.

ADVANTAGE OF THE INVENTION By this invention, the adhesive composition which can form the outstanding adhesive film which has favorable adhesiveness, a softness | flexibility, and heat resistance on the surface of the fiber base material as a rubber reinforcement is provided. The adhesive composition is suitable for binding a fiber base material and for bonding a core material formed by converging the fiber base material and rubber, particularly HNBR.

Claims (3)

  Plasticizer (C) having 5 to 30 parts by weight of resorcin-formaldehyde resin (B) and a weight average molecular weight of 400 or more with respect to 100 parts by weight of rubber component of nitrile group-containing copolymer rubber latex (A) having an iodine value of 120 or less An adhesive composition comprising 3 to 50 parts by weight.   A fiber member obtained by impregnating at least a part of a fiber base material with the adhesive composition according to claim 1. A composite comprising a vulcanized rubber member reinforced with the fiber member according to claim 2.