Method for producing an adhesive composition, rubber-organic fiber cord composite, and tire

Abstract

A purpose of the present invention is to provide a method for producing an adhesive composition, the method rendering excellent adhesiveness and production efficiency possible even when the adhesive composition contains neither formalin nor resorcinol.　This method is for producing an adhesive composition for organic fiber cords, and is characterized by adding a sodium hydroxide solution and ammonia water to a solution of a polyphenol, thereafter adding an aldehyde having an aromatic ring, and dissolving the aldehyde.

Description

Technical Field

[0001] The present invention relates to an adhesive composition, a method for producing the adhesive composition, a rubber-organic fiber cord composite, and a tire.

Background Art

[0002] Conventionally, organic fibers such as polyester fibers have a high initial elastic modulus and excellent dimensional stability during heating. Therefore, in the form of filaments, cords, cables, cord fabrics, canvas, etc., they are extremely useful as reinforcing materials for rubber articles such as tires, belts, air springs, and rubber hoses. In order to improve the adhesiveness between these fibers and rubber, various adhesive compositions have been proposed. As an adhesive composition, for example, an RFL (resorcinol-formalin-latex) adhesive containing resorcinol, formalin, rubber latex, etc. is used, and a technique for securing adhesive strength by thermosetting the RFL adhesive is known (see, for example, Patent Documents 1 to 3, etc.).

[0003] Regarding the adhesive composition, a technique using a resorcinol formalin resin obtained by initially condensing resorcinol and formalin (see Patent Documents 4 and 5), or a technique for improving the adhesive strength by pretreating a tire cord made of polyester fiber or the like with an epoxy resin is known.

[0004] Regarding the adhesive composition, a technique using a resorcinol formalin resin obtained by initially condensing resorcinol and formalin (see Patent Documents 4 and 5), or a technique for improving the adhesive strength by pretreating a tire cord made of polyester fiber or the like with an epoxy resin is known.

[0005] Here, although formalin generally used in the above-mentioned adhesive composition is an important raw material for crosslinking resorcinol, in recent years, reduction of the usage amount has been demanded in consideration of the working environment. Furthermore, similarly for resorcinol, reduction of the usage amount has been demanded from the viewpoint of the environment.

[0006] Therefore, several adhesive compositions and adhesion methods that do not contain resorcinol and formalin and are environmentally considerate have been proposed (see, for example, Patent Document 6). However, adhesive compositions that do not contain resorcinol and formalin require time for curing, resulting in problems of inferior productivity and a need for further improvement in terms of adhesion.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Patent Document 6

Summary of the Invention

Problems to be Solved by the Invention

[0008] Therefore, an object of the present invention is to provide a method for manufacturing an adhesive composition that can achieve excellent adhesion and productivity even when formalin and resorcinol are not contained. Another object of the present invention is to provide a rubber-organic fiber cord composite and a tire that have a low environmental load and excellent adhesion between the rubber and the organic fiber cord.

Means for Solving the Problems

[0009] As a result of investigations to achieve the above object, the present inventors have focused on the fact that by including specific polyphenols and aldehydes having an aromatic ring in the adhesive composition, high adhesive strength can be achieved even when formalin and resorcin are not used. However, when polyphenols and aldehydes having an aromatic ring are used, there is a problem that these compounds do not dissolve in the solvent in the adhesive composition and cannot be used as components of the adhesive composition as they are. Therefore, as a result of further intensive research, the present inventors have found that by including aqueous ammonia at a specific concentration in the adhesive composition, the above-mentioned polyphenols and aldehydes can be surely dissolved, and excellent adhesiveness and productivity can be achieved.

[0010] That is, the method for producing an adhesive composition of the present invention is a method for producing an adhesive composition for an organic fiber cord, characterized in that a sodium hydroxide solution and aqueous ammonia are added to a solution in which polyphenols are dissolved, and then aldehydes having an aromatic ring are added and dissolved. With the above configuration, excellent adhesiveness and productivity can be achieved even when formalin and resorcin are not included.

[0011] In addition, in the method for producing an adhesive composition of the present invention, it is preferable to further add a rubber latex after dissolving the aldehydes having an aromatic ring. This is because even more excellent adhesiveness and productivity can be achieved.

[0012] Also, in the method for producing an adhesive composition of the present invention, it is preferable to further add an isocyanate compound after adding the rubber latex. This is because even more excellent adhesiveness can be achieved.

[0013] Furthermore, in the method for producing an adhesive composition of the present invention, the polyphenols preferably have three or more hydroxyl groups. This is because even more excellent adhesiveness can be achieved.

[0014] Furthermore, in the method for producing the adhesive composition of the present invention, it is preferable that the aldehydes have two or more aldehyde groups. This is because more excellent adhesiveness can be achieved.

[0015] In addition, in the method for producing the adhesive composition of the present invention, it is preferable that the concentration of the aqueous ammonia is 5 to 50%. This is because more excellent adhesiveness and productivity can be achieved.

[0016] Also, in the method for producing the adhesive composition of the present invention, it is preferable that the content of the aqueous ammonia after drying (solid content) is 0.1 to 5.0% by mass. This is because more excellent adhesiveness and productivity can be achieved.

[0017] Furthermore, in the method for producing the adhesive composition of the present invention, it is preferable that the concentration of the sodium hydroxide solution is 0.1 to 3 mol / L. This is because more excellent adhesiveness and productivity can be achieved.

[0018] Furthermore, in the method for producing the adhesive composition of the present invention, it is preferable that the content of the sodium hydroxide solution after drying (solid content) is 1.0 to 10% by mass. This is because more excellent adhesiveness and productivity can be achieved.

[0019] The rubber - organic fiber cord composite of the present invention is a rubber - organic fiber cord composite including a rubber member and an organic fiber cord, wherein at least a part of the organic fiber cord is coated with an adhesive composition produced by the method for producing the adhesive composition of the present invention described above. With the above configuration, the environmental load is small, and the adhesiveness between the rubber and the organic fiber cord can be improved.

[0020] The tire of the present invention is characterized by using the rubber - organic fiber cord composite of the present invention described above. With the above configuration, the environmental load is small, and the adhesiveness between the rubber and the organic fiber cord can be improved.

Advantages of the Invention

[0021] According to the present invention, even when formalin and resorcin are not included, a method for manufacturing an adhesive composition capable of achieving excellent adhesiveness and productivity can be provided. Further, according to the present invention, a rubber-organic fiber cord composite and a tire with less environmental load and excellent adhesiveness between rubber and an organic fiber cord can be provided.

Mode for Carrying Out the Invention

[0022] <Method for Manufacturing Adhesive Composition> Hereinafter, an embodiment of the method for manufacturing the adhesive composition of the present invention will be described in detail. The method for manufacturing the adhesive composition of the present invention is a method for manufacturing an adhesive composition for an organic fiber cord. The present invention is characterized in that a sodium hydroxide solution and aqueous ammonia are added to a solution in which polyphenols are dissolved, and then aldehydes having an aromatic ring are added and dissolved.

[0023] By including specific polyphenols and aldehydes having an aromatic ring in the adhesive composition, high adhesive strength can be achieved even when formalin and resorcin are not used. However, particularly for aldehydes having an aromatic ring, there has been a problem that they are difficult to dissolve and cannot be used as a component contained in the adhesive composition only by blending and mixing. Therefore, in the manufacturing method of the present invention, by adding a sodium hydroxide solution and aqueous ammonia to a solution in which polyphenols are dissolved, and then adding aldehydes having an aromatic ring, the above-mentioned aldehydes can be surely dissolved, and in addition to excellent adhesiveness, productivity can also be improved.

[0024] (Solution in which polyphenols are dissolved) The solution in which the polyphenols are dissolved is a solution obtained by dissolving the polyphenols in a solvent. In the method for producing the adhesive composition of the present invention, polyphenols are contained as a resin component. By including polyphenols in the adhesive composition, the adhesiveness of the resin composition can be enhanced. Here, the polyphenols are water-soluble polyphenols, and there is no limitation as long as they are polyphenols other than resorcinol (resorcinol), and the number of aromatic rings and the number of hydroxyl groups can be appropriately selected.

[0025] Also, from the viewpoint of achieving more excellent adhesiveness, the polyphenols preferably have a plurality of hydroxyl groups, and more preferably have three or more hydroxyl groups. Furthermore, when the polyphenols are polyphenols containing a plurality of (two or more) aromatic rings, in these aromatic rings, each has two or three hydroxyl groups carried at the meta position, or it is more preferable that the ortho position of these hydroxyl functional groups is not substituted. That is, it means that the two carbon atoms located on both sides of the hydroxylated carbon atom (i.e., the position carrying the hydroxyl group) are not substituted.

[0026] Examples of the polyphenols having three or more hydroxyl groups described above include the following polyphenols. Phloroglucinol:

Chemical formula

Chemical formula

Chemical formula

[0027] In addition, from the perspective of ensuring better adhesiveness, the content of the polyphenols in the adhesive composition is preferably 2.5% by mass or more, more preferably 3.0% by mass or more, and even more preferably 3.5% by mass or more in terms of the content after drying (solid content). Also, from the perspective of obtaining better workability, the content of the polyphenols is preferably 15% by mass or less, more preferably 13% by mass or less, and even more preferably 11% by mass or less in terms of the content after drying (solid content).

[0028] The solvent for dissolving the polyphenol solution is not particularly limited, and examples include water and sodium hydroxide solution. From the perspective of more surely dissolving the polyphenol, it is preferable to contain both water and sodium hydroxide solution. Regarding the water, from the perspective of more surely dissolving the polyphenol, it is preferably 40°C or higher, and more preferably 45°C or higher.

[0029] (Ammonia water) In the method for producing the adhesive composition of the present invention, ammonia water is added to the solution in which the polyphenol is dissolved. Since this ammonia water can surely dissolve the above-mentioned polyphenols and aldehydes having an aromatic ring, high adhesiveness can be imparted to the adhesive composition, and the productivity of the adhesive composition can be improved. In particular, although the polyphenols are water-soluble, the aldehyde having an aromatic ring described later is difficult to dissolve. Therefore, in the present invention, by using ammonia water with a specific concentration, it becomes possible to surely dissolve it.

[0030] Here, the concentration of the aqueous ammonia is preferably 5 to 50%. The reason for setting the concentration of the aqueous ammonia to 5% or more is that it can surely dissolve the aldehydes having the aromatic ring in particular. From the same viewpoint, the concentration of the aqueous ammonia is preferably 10% or more, and more preferably 15% or more. On the other hand, the reason for setting the concentration of the aqueous ammonia to 50% or less is to maintain heat-resistant adhesiveness. From the same viewpoint, the concentration of the aqueous ammonia is preferably 40% or less, and more preferably 35% or less.

[0031] In addition, from the viewpoint of more excellent production and adhesiveness, the content of the aqueous ammonia in the adhesive composition of the present invention is preferably 0.5 to 5.0% by mass in terms of the content (solid content) after drying of the aqueous ammonia in the adhesive composition of the present invention.

[0032] (Sodium hydroxide solution) In the method for producing the adhesive composition of the present invention, a sodium hydroxide solution is added together with the aqueous ammonia to the solution in which the polyphenol is dissolved. By using the sodium hydroxide solution together with the above-described aqueous ammonia, polyphenols and aldehydes having an aromatic ring can be surely dissolved, so that high adhesiveness can be imparted to the adhesive composition and the productivity of the adhesive composition can be increased. In particular, although the polyphenols are water-soluble, the aldehydes having an aromatic ring, which will be described later, are difficult to dissolve. Therefore, they can be more surely dissolved and the productivity can be further increased.

[0033] Here, the concentration of the sodium hydroxide solution is not particularly limited, but it is preferably 0.1 mol / L or more. This is because the above-mentioned polyphenols and aldehydes having an aromatic ring can be more reliably dissolved. From the same viewpoint, the concentration of the sodium hydroxide solution is preferably 0.3 mol / L or more, and more preferably 0.6 mol / L or more. On the other hand, the concentration of the sodium hydroxide solution is preferably 3 mol / L or less in order to maintain heat-resistant adhesiveness. From the same viewpoint, the concentration of the sodium hydroxide solution is preferably 2 mol / L or less, and more preferably 1.5 mol / L or less.

[0034] In addition, the content of the sodium hydroxide solution in the adhesive composition of the present invention after drying (solid content: sodium hydroxide) is not particularly limited, but from the viewpoint of more reliably dissolving the above-mentioned polyphenols and aldehydes having an aromatic ring, it is preferably 0.1% by mass, more preferably 0.3% by mass or more, and even more preferably 0.5% by mass or more. Furthermore, the content of the sodium hydroxide solution in the adhesive composition of the present invention after drying (solid content: sodium hydroxide) is preferably 5% by mass or less, more preferably 4% by mass or less, and even more preferably 3% by mass or less from the viewpoint of increasing the concentration of the above-mentioned polyphenols and aldehydes having an aromatic ring and achieving more excellent adhesiveness.

[0035] Furthermore, the pH of the adhesive composition of the present invention containing the aqueous ammonia and the sodium hydroxide solution is not particularly limited, but it is preferably 8 to 14, and more preferably 9 to 13 because the solubility becomes good.

[0036] (Aldehydes having an aromatic ring) And in the method for producing the adhesive composition of the present invention, after adding the aqueous ammonia and the sodium hydroxide, aldehydes having an aromatic ring are added. By containing aldehydes having an aromatic ring in the adhesive composition, high adhesiveness can be achieved together with the above-described polyphenols.

[0037] Here, the aldehydes having an aromatic ring are not particularly limited, and the number of aromatic rings and the number of aldehyde groups can be appropriately selected. Note that the aldehydes having an aromatic ring do not contain formaldehyde. In the present invention, "not containing formaldehyde" means that the mass content of formaldehyde based on the total mass of aldehydes is less than 0.5% by mass.

[0038] Also, from the viewpoint of achieving more excellent adhesiveness, the aldehydes having an aromatic ring preferably have two or more aldehyde groups. Since the aldehydes are crosslinked and condensed by a plurality of aldehyde groups, the crosslinking degree of the thermosetting resin can be increased, and thus the adhesiveness can be further enhanced. Furthermore, when the aldehydes have two or more aldehyde groups, it is more preferable that two or more aldehyde groups are present in one aromatic ring. Each aldehyde group can be present at the ortho, meta, or para position in one aromatic ring.

[0039] Examples of such aldehydes include 1,2-benzenedicarboxaldehyde, 1,3-benzenedicarboxaldehyde, 1,4-benzenedicarboxaldehyde, 2-hydroxybenzene-1,3,5-tricarboxaldehyde, and mixtures of these compounds.

[0040] Among these, from the viewpoint of achieving more excellent adhesiveness, it is preferable to use at least 1,4-benzenedicarboxaldehyde as the aldehydes having an aromatic ring.

Chemical formula

[0041] In addition, among the aldehydes having an aromatic ring, not only those having a benzene ring but also heteroaromatic compounds are included. Examples of the aldehydes that are heteroaromatic compounds include aldehydes having a furan ring as shown below.

Chemical formula

[0042] Examples of the aldehydes having the above furan ring include the following compounds.

Chemical formula

[0043] Note that the content of the aldehydes having an aromatic ring in the adhesive composition of the present invention after drying (solid content) is not particularly limited, but from the viewpoint of ensuring better adhesiveness, it is preferably 1.0% by mass or more, more preferably 2.0% by mass or more, and even more preferably 2.5% by mass or more. Also, from the viewpoint that the aldehydes having an aromatic ring are surely dissolved and better workability is obtained, the content of the aldehydes having an aromatic ring in the adhesive composition of the present invention after drying (solid content) is preferably 11% by mass or less, more preferably 10% by mass or less, and even more preferably 9% by mass or less.

[0044] (rubber latex) In addition, in the method for producing the adhesive composition of the present invention, after adding the aldehydes having an aromatic ring, rubber latex can be further added. By adding rubber latex, the adhesiveness of the obtained adhesive composition to the rubber member can be further improved.

[0045] Here, the rubber latex is not particularly limited. In addition to natural rubber (NR), synthetic rubbers such as polyisoprene rubber (IR), styrene-butadiene copolymer rubber (SBR), polybutadiene rubber (BR), ethylene-propylene-diene rubber (EPDM), chloroprene rubber (CR), halogenated butyl rubber, acrylonitrile-butadiene rubber (NBR), and vinyl pyridine-styrene-butadiene copolymer rubber (Vp) can be used. These rubber components may be used alone or in combination of two or more.

[0046] Note that the content of the solid component (ratio as the dried product) of the rubber latex in the adhesive composition of the present invention is not particularly limited, but is preferably 40 to 99% by mass, and more preferably 70 to 95% by mass.

[0047] Furthermore, in the method for producing the adhesive composition of the present invention, when adding the rubber latex, it is more preferable to age the rubber latex after the addition. This is because the latex can be more reliably coagulated, the handleability of the adhesive composition can be improved, and the adhesiveness can also be improved. Here, the aging of the rubber latex refers to a process of allowing a certain period of time to elapse after adding and mixing the latex for the purpose of improving the characteristics of the latex. The conditions are not particularly limited. For example, the aging of the rubber latex can be carried out at 20°C or higher, preferably 40°C or higher, and preferably for 2 hours or more.

[0048] (Isocyanate compound)

[0049] Also, in the method for producing the adhesive composition of the present invention, an isocyanate compound can be further added. By adding the isocyanate compound, the adhesiveness of the obtained adhesive composition can be further improved.

[0050] In the method for producing the adhesive composition of the present invention, the timing of adding the isocyanate compound is not particularly limited, but it is preferably added after adding the rubber latex. This is because the adhesive promoting action of the resin material by the isocyanate compound can be more effectively exerted, and more excellent adhesiveness can be realized.

[0051] Here, the isocyanate compound is a compound having an action of promoting adhesion to a resin material (for example, polyphenols, aldehydes having an aromatic ring), which is the adherend of the adhesive composition, and is a compound having an isocyanate group as a polar functional group.

[0052] The type of the isocyanate compound is not particularly limited, but from the viewpoint of further improving adhesiveness, it is preferably an (blocked) isocyanate group-containing aromatic compound. When the isocyanate compound is included in the adhesive composition of the present invention, the (blocked) isocyanate group-containing aromatic is distributed in the vicinity of the interface between the adherend fiber and the adhesive composition, and this is a function that can obtain an adhesion promoting effect. Due to these functional effects, the adhesion to the organic cord can be further enhanced. The (blocked) isocyanate group-containing aromatic compound is an aromatic compound having a (blocked) isocyanate group. Further, the “(blocked) isocyanate group” means a blocked isocyanate group or an isocyanate group, and includes, in addition to the isocyanate group, a blocked isocyanate group generated by reacting with a blocking agent for the isocyanate group, an unreacted isocyanate group with respect to the isocyanate group, or an isocyanate group generated by dissociation of the blocking agent of the blocked isocyanate group.

[0053] Furthermore, the (blocked) isocyanate group-containing aromatic compound preferably contains a molecular structure in which aromatics are bonded by an alkylene chain, and more preferably contains a molecular structure in which aromatics are methylene-bonded. Examples of the molecular structure in which aromatics are bonded by an alkylene chain include molecular structures found in diphenylmethane diisocyanate, polyphenylene polymethylene polyisocyanate, condensates of phenols and formaldehyde, and the like.

[0054] Examples of the (blocked) isocyanate group-containing aromatic compound include compounds containing an aromatic polyisocyanate and a thermal dissociation blocking agent, water-dispersible compounds containing components obtained by blocking diphenylmethane diisocyanate or an aromatic polyisocyanate with a thermal dissociation blocking agent, aqueous urethane compounds, and the like.

[0055] Suitable examples of the compound containing an aromatic polyisocyanate and a thermal dissociation blocking agent include blocked isocyanate compounds containing diphenylmethane diisocyanate and a known isocyanate blocking agent. Examples of the water-dispersible compound containing components obtained by blocking diphenylmethane diisocyanate or an aromatic polyisocyanate with a thermal dissociation blocking agent include reaction products obtained by blocking diphenylmethane diisocyanate or polymethylene polyphenyl polyisocyanate with a known blocking agent for blocking isocyanate groups. Specifically, commercially available blocked polyisocyanate compounds such as Elastron BN69 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), Elastron BN77 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), and Makecate TP-10 (manufactured by Meisei Chemical Industry Co., Ltd.) can be used.

[0056] The aqueous urethane compound is obtained by reacting an organic polyisocyanate compound (α) containing a molecular structure in which aromatics are bonded by an alkylene chain, preferably a molecular structure in which aromatics are methylene-bonded, a compound (β) having a plurality of active hydrogens, and a thermal dissociable blocking agent (γ) for isocyanate groups. Further, due to its flexible molecular structure, the aqueous urethane compound (F) has not only the action as an adhesion improver but also the action of suppressing the fluidization of the adhesive at high temperatures as a flexible crosslinking agent. Note that "aqueous" indicates water solubility or water dispersibility, and "water solubility" does not necessarily mean complete water solubility, but means partially water-soluble or those that do not phase-separate in the aqueous solution of the adhesive composition of the present invention.

[0057] Here, as the aqueous urethane compound (F), for example, the following general formula (I): [Chemical formula] (In the formula, A represents the residue obtained by eliminating the active hydrogen of the organic polyisocyanate compound (α) containing a molecular structure in which aromatics are bonded by an alkylene chain, Y represents the residue obtained by eliminating the active hydrogen of the thermal dissociable blocking agent (γ) for isocyanate groups, Z represents the residue obtained by eliminating the active hydrogen of the compound (δ), X is the residue obtained by eliminating the active hydrogen of the compound (β) having a plurality of active hydrogens, n is an integer of 2 to 4, and p + m is an integer of 2 to 4 (m ≧ 0.25).) The aqueous urethane compound represented thereby is preferred.

[0058] Examples of the organic polyisocyanate compound (α) containing a molecular structure in which aromatics are bonded by an alkylene chain include methylene diphenyl polyisocyanate and polymethylene polyphenyl polyisocyanate. Further, the compound (β) having a plurality of active hydrogens preferably has 2 to 4 active hydrogens and is a compound having an average molecular weight of 5,000 or less. Examples of such a compound (β) include (i) polyhydric alcohols having 2 to 4 hydroxyl groups, (ii) polyvalent amines having 2 to 4 primary and / or secondary amino groups, (iii) amino alcohols having 2 to 4 primary and / or secondary amino groups and hydroxyl groups, (iv) polyester polyols having 2 to 4 hydroxyl groups, (v) polybutadiene polyols having 2 to 4 hydroxyl groups and copolymers thereof with other vinyl monomers, (vi) polychloroprene polyols having 2 to 4 hydroxyl groups and copolymers thereof with other vinyl monomers, and (vii) polyether polyols having 2 to 4 hydroxyl groups, which are C2-C4 alkylene oxide adducts of polyvalent amines, polyvalent phenols, and amino alcohols, C2-C4 alkylene oxide adducts of polyhydric alcohols having 3 or more carbon atoms, C2-C4 alkylene oxide copolymers, or C3-C4 alkylene oxide polymers, etc. Furthermore, the thermally dissociable blocking agent (γ) for the isocyanate group is a compound capable of liberating the isocyanate group by heat treatment, and known isocyanate blocking agents can be mentioned. Furthermore, the compound (δ) is a compound having at least one active hydrogen and an anionic and / or nonionic hydrophilic group. Examples of the compound having at least one active hydrogen and an anionic hydrophilic group include aminosulfonic acids such as taurine, N-methyltaurine, N-butyltaurine, and sulfanilic acid, and aminocarboxylic acids such as glycine and alanine. On the other hand, examples of the compound having at least one active hydrogen and a nonionic hydrophilic group include compounds having a hydrophilic polyether chain.

[0059] In the adhesive composition of the present invention, the content of the isocyanate compound is not particularly limited, but from the viewpoint of more surely ensuring excellent adhesiveness, it is preferably in the range of 15 to 70% by mass. The content of the isocyanate compound is the mass of the dried product (solid content ratio).

[0060] (Other components) In the method for producing the adhesive composition of the present invention, in addition to the above-mentioned polyphenols, aldehydes having an aromatic ring, aqueous ammonia and sodium hydroxide solution, and as optional components, a rubber latex, an isocyanate compound, and further, an epoxy compound, a coloring agent, a filler, an antioxidant, a stabilizer, water and other components can be further added.

[0061] In addition, in the method for producing the adhesive composition of the present invention, the adhesive composition can be composed of a one-bath treatment liquid or a two-bath treatment liquid. Here, the one-bath treatment is a treatment in which an organic fiber cord to be adhered is dipped in one treatment liquid (adhesive composition) to adhere the adhesive composition to the surface of the organic fiber cord. Also, for the two-bath treatment, an organic fiber cord to be adhered is dipped in two treatment liquids in sequence, which is a treatment liquid for adhering the adhesive composition to the surface of the organic fiber cord. Therefore, when the obtained adhesive composition is a two-bath treatment liquid, the combined treatment liquid of the first bath and the second bath is the adhesive composition.

[0062] When the adhesive composition is composed of a one-bath treatment liquid, as the order of adding the above-mentioned components, for example, after adding a solvent for dissolving polyphenols and other components such as the isocyanate compound and the epoxy compound, polyphenols are added to form a solution in which polyphenols are dissolved, then the aqueous ammonia is added, and then the aldehydes having an aromatic ring are added. By going through this process, the treatment liquid is prepared. Then, by dipping the organic fiber cord in the treatment liquid, the adhesive composition can be coated on the organic fiber cord.

[0063] Further, when the adhesive composition is composed of a two-bath treatment liquid, for example, a composition obtained by adding other components such as the isocyanate compound and epoxy compound is prepared as a one-bath treatment liquid, and the organic fiber cord is dipped therein. Then, after adding polyphenols to a specific solvent to form a solution in which the polyphenols are dissolved, ammonia water is added, and then a composition obtained by adding aldehydes having an aromatic ring is prepared as a two-bath treatment liquid, and the organic fiber cord dipped in the one-bath treatment liquid is dipped again. By this process, the adhesive composition can be coated on the organic fiber cord.

[0064] <Rubber-organic fiber cord composite> The rubber-organic fiber cord composite of the present invention is a rubber-organic fiber cord composite including a rubber member and an organic fiber cord, wherein at least a part of the organic fiber cord is coated with the adhesive composition produced by the production method of the present invention described above. Since the rubber-organic fiber cord composite of the present invention uses the adhesive composition produced by the production method of the present invention, it has less environmental load and excellent adhesiveness between the rubber and the organic fiber cord. Here, the use of the rubber-organic fiber cord composite of the present invention is not particularly limited. For example, it can be used as a member such as a belt, an air spring, or a hose.

[0065] Also, the type of the organic fiber cord is not particularly limited and can be appropriately selected according to the use. For example, when this organic fiber cord is used as a reinforcing material, first, a monofilament cord of the raw yarn of the spun organic fiber or a twisted cord obtained by twisting multifilament cords can be used as the organic fiber cord. Then, the organic fiber cord is embedded in rubber that coats the organic fiber cord using an adhesive composition and vulcanized to be adhered, thereby forming an organic fiber cord-rubber composite, and this organic fiber cord-rubber composite can be used as a reinforcing member of a rubber article such as a tire. Furthermore, the material of the organic fiber cord is not particularly limited, and examples thereof include resin fiber materials typified by polyethylene terephthalate (PET) fiber cords, polyesters, aliphatic polyamide fiber cords such as 6-nylon, 6,6-nylon, and 4,6-nylon, protein fiber cords such as artificial fibroin fibers, polyketone fiber cords, aromatic polyamide fiber cords typified by polynonamethylene terephthalamide and paraphenylene terephthalamide, acrylic fiber cords, carbon fiber cords, and cellulose fiber cords such as rayon and lyocell, or fiber materials obtained by mixing these.

[0066] In the rubber-organic fiber cord composite of the present invention, the adhesive composition produced by the production method of the present invention only needs to cover at least a part of the organic fiber cord. However, from the viewpoint of further improving the adhesiveness between the rubber and the organic fiber cord, it is preferable that the adhesive composition of the present invention coats the entire surface of the organic fiber cord.

[0067] <Tire> The tire of the present invention is characterized by using the rubber-organic fiber cord composite of the present invention described above. In the tire of the present invention, the rubber-organic fiber cord composite of the present invention described above can be used, for example, as a carcass ply, a belt layer, a belt reinforcing layer, a belt-around reinforcing layer such as a flipper, or the like.

[0068] The pneumatic tire of the present invention is not particularly limited other than using the above-described rubber article, and can be manufactured according to a conventional method. In addition, as the gas filled in the tire, in addition to normal air or air with an adjusted oxygen partial pressure, inert gases such as nitrogen, argon, and helium can be used.

Examples

[0069] Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples at all.

[0070] According to the following manufacturing conditions (Manufacturing Examples 1 to 6), an adhesive composition as a sample was prepared, and it was confirmed whether the desired adhesive composition could be manufactured.

[0071] (1) Manufacturing Example 1 of Adhesive Composition (Comparative Example) To 3.2 g of 1,4-benzenedicarboxaldehyde, 9.1 g of 1 mol / L sodium hydroxide and 91.0 g of water at 100 °C were added, and stirring was carried out for 4 hours while maintaining 60 °C. As a result, most of the 1,4-benzenedicarboxaldehyde precipitated without dissolving, and the desired adhesive composition could not be obtained.

[0072] (2) Manufacturing Example 2 of Adhesive Composition (Comparative Example) To 3.2 g of 1,4-benzenedicarboxaldehyde, 3.7 g of 25% aqueous ammonia and 87.2 g of water at 100 °C were added, and stirring was carried out for 4 hours while maintaining 60 °C. As a result, most of the 1,4-benzenedicarboxaldehyde did not dissolve and the particles aggregated, and the desired adhesive composition could not be obtained.

[0073] (3) Manufacturing Example 3 of Adhesive Composition (Comparative Example) To 3.2 g of 1,4-benzenedicarboxaldehyde, 9.1 g of 1 mol / L sodium hydroxide, 3.7 g of 25% aqueous ammonia and 87.2 g of water at 100 °C were added, and stirring was carried out for 4 hours while maintaining 60 °C. As a result, most of the 1,4-benzenedicarboxaldehyde did not dissolve and the particles aggregated, and the desired adhesive composition could not be obtained.

[0074] (4) Manufacturing Example 4 of Adhesive Composition (Comparative Example) First, phloroglucinol was dissolved in water at 100 °C to obtain a 10% phloroglucinol solution. Subsequently, 9.1 g of 1 mol / L sodium hydroxide and 75.8 g of water at 100°C were added to 16.8 g of phloroglucinol solution, and then while adding 3.2 g of 1,4-benzenedicarboxaldehyde, stirring was carried out for 6 hours while maintaining 60°C. As a result, although part of the 1,4-benzenedicarboxaldehyde dissolved, part remained undissolved, and the desired adhesive composition could not be obtained.

[0075] (5) Production Example 5 (Comparative Example) of Adhesive Composition First, phloroglucinol was dissolved in water at 100°C to obtain a 10% phloroglucinol solution. Subsequently, 3.7 g of 25% aqueous ammonia and 82.2 g of water at 100°C were added to 16.8 g of phloroglucinol solution, and then while adding 3.2 g of 1,4-benzenedicarboxaldehyde, stirring was carried out for 6 hours while maintaining 60°C. As a result, most of the 1,4-benzenedicarboxaldehyde did not dissolve and became a suspension, and the desired adhesive composition could not be obtained.

[0076] (6) Production Example 6 (Example) of Adhesive Composition First, phloroglucinol was dissolved in water at 100°C to obtain a 10% phloroglucinol solution. Subsequently, 9.1 g of 1 mol / L sodium hydroxide, 3.7 g of 25% aqueous ammonia and 82.2 g of water at 100°C were added to 16.8 g of phloroglucinol solution, and then while adding 3.2 g of 1,4-benzenedicarboxaldehyde, stirring was carried out for 0.5 hour while maintaining 60°C. As a result, all of the 1,4-benzenedicarboxaldehyde dissolved, and the desired adhesive composition could be obtained. Moreover, the obtained adhesive composition can achieve high adhesiveness.

[0077] Incidentally, regarding phloroglucinol, 1,4-benzenedicarboxaldehyde, sodium hydroxide, and ammonia used in the above Production Examples 1 to 6, they are as follows. * Phloroglucinol: Manufactured by Fujifilm Wako Pure Chemical Corporation *1,4 - Benzenedicarboxaldehyde: manufactured by Tokyo Chemical Industry Co., Ltd. *Sodium hydroxide: manufactured by Kanto Chemical Co., Inc., 1N NaOH aqueous solution *Ammonia water: manufactured by Kanto Chemical Co., Inc., 25% ammonia aqueous solution

[0078] From the results of Production Examples 1 to 6, it can be understood that the adhesive composition prepared according to the production method of the present invention (Production Example 6) is excellent in productivity compared to the adhesive composition prepared according to the conventional production method.

[0079] <Adhesion evaluation> In addition, for the samples of Production Examples 4 and 6, the following adhesion evaluation was also carried out. A polyester cord for a tire coated with the adhesive compositions of Production Examples 4 and 6 respectively was embedded in an unvulcanized rubber composition containing a rubber component composed of natural rubber and styrene - butadiene copolymer, carbon black, and a cross - linking agent. Using this as a test piece, it was vulcanized at 160 °C for 20 minutes under a pressure of 20 kgf / cm 2 . For the sample of Production Example 4, the supernatant of the prepared adhesive composition was used as the coating liquid for the above cord. The obtained vulcanizate was cooled to room temperature, the cord was dug out from the vulcanizate, and the resistance force (N / cord) when peeling the cord from the vulcanizate at a speed of 30 cm / min was measured at a room - temperature atmosphere temperature of 25 ± 1 °C. At this time, this resistance force was used as an index for adhesion evaluation.

[0080] As a result of measuring the peeling resistance force of the test pieces using each sample, when the peeling resistance force of the test piece using the sample of Production Example 4 was set to 100, it was found that the peeling resistance force of the test piece using the sample of Production Example 6 was 111. Therefore, it can be seen that the adhesive composition prepared according to the production method of the present invention (Production Example 6) is excellent in productivity and also excellent in adhesion compared to the adhesive composition prepared according to the conventional production method.

Industrial applicability

[0081] According to the present invention, it is possible to provide a method for producing an adhesive composition that can achieve excellent adhesiveness and productivity even when formalin and resorcin are not included. Further, according to the present invention, it is possible to provide a rubber-organic fiber cord composite and a tire that have a small environmental load and excellent adhesiveness between the rubber and the organic fiber cord.

Claims

1. A method for producing an adhesive composition for organic fiber cords, comprising: adding a sodium hydroxide solution and aqueous ammonia to a solution in which polyphenols are dissolved, and then adding aldehydes having an aromatic ring and dissolving them; after dissolving the aldehydes having an aromatic ring, further adding a rubber latex; after adding the rubber latex, further adding an isocyanate compound; wherein the concentration of the aqueous ammonia is 5 to 50%, and the concentration of the sodium hydroxide solution is 0.1 to 3 mol / L, a method for producing an adhesive composition.

2. The method for producing an adhesive composition according to claim 1, wherein the polyphenols have three or more hydroxyl groups.

3. The method for producing an adhesive composition according to claim 1 or 2, wherein the aldehydes have two or more aldehyde groups.

Images