WO2016052451A1

WO2016052451A1 - Metal cord-rubber composite body

Info

Publication number: WO2016052451A1
Application number: PCT/JP2015/077404
Authority: WO
Inventors: 淳一山岸; 信一武者; 芳彦金冨
Original assignee: 株式会社ブリヂストン
Priority date: 2014-10-01
Filing date: 2015-09-28
Publication date: 2016-04-07

Abstract

The present invention is a metal cord-rubber composite body obtained by coating one of the following with a rubber composition: a metal cord that comprises a single steel wire having brass plating on the circumferential surface thereof; or a metal cord obtained by twisting together a plurality of the steel wires. The metal cord-rubber composite body is characterized in that: the rubber composition is obtained by blending a rubber component (A) and 0.1-10 parts by mass of a resorcinol resin with respect to 100 parts by mass of the resin component (A); and the brass plating is three-element or four-element plating comprising 58-70 mass% of Cu, 0.5-10 mass% of at least one metal selected from Co and Ni, and a remainder of Zn. By coating a metal cord having three-element or four-element plating that is specific brass plating with a specific rubber composition in a rubber product reinforced by a metal cord, the present invention provides a metal cord-rubber composite body having improved adhesiveness.

Description

Metal cord-rubber composite

The present invention relates to a metal cord-rubber composite formed by coating a specific rubber composition on a metal cord made of steel wire or a single wire with brass plating applied to the peripheral surface, or a metal cord formed by twisting the steel wire. .

Rubber products such as tires, belts and hoses are reinforced with reinforcing materials such as metal cords such as steel cords and organic fibers. These rubber products are required to firmly bond rubber and a reinforcing material, particularly a metal cord.
For bonding the rubber and the reinforcing material, there is a method using an adhesive. As an example, in the kneading process of rubber, in the kneading process, an adhesive is blended with various other compounding agents and kneaded, by reacting alkylphenols such as p-tert-octylphenol and p-nonylphenol with formalins. It is known that a cocondensate obtained by reacting resorcin with the obtained cocondensate is used as an adhesive used in a rubber processing step (see Patent Document 1).

By the way, metal cords such as steel cords have been used as reinforcing materials for rubber products such as tires, belts, hoses, etc., for example, steel wires with a brass plating layer on the peripheral surface of the wire. As the brass plating, ternary plating or quaternary plating is known (for example, see Patent Documents 2 to 5). However, the adhesion of these ternary plating or quaternary plating may be reduced by a combination with a rubber composition covering a metal cord.

Japanese Patent Application Laid-Open No. 06-234824 JP-A-54-89940 JP-A-55-71887 JP-A-57-56110 JP-A-61-72545

The present inventors paid attention to the importance of further improving the adhesion between the above-described metal cord and rubber. The present invention relates to a metal cord having improved adhesion by coating a specific rubber composition on a metal cord having ternary or quaternary plating, which is a specific brass plating, in a rubber product reinforced with a metal cord. -An object is to provide a rubber composite.

The inventors of the present invention have found that when a rubber composition containing a resorcin resin is combined with a metal cord having ternary or quaternary plating as brass plating, the initial adhesiveness and wet heat adhesiveness are greatly improved.
That is, the present invention
[1] A metal cord-rubber composite formed by coating a rubber composition on a metal cord composed of a single wire of steel wire having brass plating applied to its peripheral surface, or a metal cord formed by twisting the steel wire, The rubber composition comprises a rubber component (A) and 100 parts by mass of the rubber component (A), and 0.1 to 10 parts by mass of a resorcin resin, and the brass plating comprises 58 to 70% by mass of Cu, Co And a metal cord-rubber composite characterized in that it is a ternary or quaternary plating composed of 0.5 to 10% by mass of at least one metal selected from Ni and the balance of Zn, and [2] the resorcin resin Are represented by the structural unit derived from p-tert-butylphenol represented by the following formula (1), the structural unit derived from o-phenylphenol represented by the following formula (2), and the following formula (3). Softening point comprises a constitutional unit derived from resorcinol is characterized in that it is a 0.99 ° C. or less of the co-condensate (B) above [1] metal cord according - a rubber composite.

In a rubber product reinforced with a metal cord, a metal cord-rubber composite having improved adhesion by coating a specific rubber composition on a metal cord having a ternary or quaternary plating, which is a specific brass plating Can be provided.

[Metal cord-Rubber composite]
The metal cord-rubber composite of the present invention is a metal cord formed by coating a rubber composition on a metal cord made of a single wire of steel wire with brass plating applied to the peripheral surface or a metal cord formed by twisting the steel wire. A rubber composite comprising the rubber component (A) and 0.1 to 10 parts by mass of resorcin resin per 100 parts by mass of the rubber component (A), and the brass plating Is ternary or quaternary plating consisting of 58 to 70% by mass of Cu, 0.5 to 10% by mass of at least one metal selected from Co and Ni, and the balance being Zn.
Metal cord-rubber composite comprising a metal cord having ternary or quaternary plating and a rubber composition in which 0.1 to 10 parts by mass of a resorcin resin is blended with 100 parts by mass of the rubber component (A) The body can greatly improve initial adhesion and wet heat adhesion.

[Rubber composition]
Hereinafter, the rubber composition according to the present invention will be described in detail. The rubber composition according to the present invention comprises 0.1 to 10 parts by mass of a resorcin resin per 100 parts by mass of the rubber component (A) and the rubber component (A). When the blending amount of the resorcin resin is less than 0.1 parts by mass with respect to 100 parts by mass of the rubber component (A), sufficient adhesion cannot be obtained. On the other hand, when the compounding amount of the resorcin resin exceeds 10 parts by mass with respect to 100 parts by mass of the rubber component (A), the adhesion reaction during vulcanization proceeds excessively, resulting in a decrease in adhesiveness.
From the above viewpoint, the resorcin resin is preferably 0.2 parts by mass or more and 8 parts by mass or less, and more preferably 0.5 parts by mass or more and 6 parts by mass or less with respect to 100 parts by mass of the rubber component (A). It is.

<Rubber component (A)>
Examples of the rubber component (A) that can be used in the rubber composition according to the present invention include natural rubber, epoxidized natural rubber, deproteinized natural rubber and other modified natural rubber, polyisoprene rubber (IR), styrene- Butadiene copolymer rubber (SBR), polybutadiene rubber (BR), ethylene-butadiene copolymer rubber (EBR), propylene-butadiene copolymer rubber (PBR), acrylonitrile-butadiene copolymer rubber (NBR), isoprene Examples include various synthetic rubbers such as isobutylene copolymer rubber (IIR), ethylene / propylene-diene copolymer rubber (EPDM), and halogenated butyl rubber (HR). Of these, highly unsaturated rubbers such as natural rubber, styrene-butadiene copolymer rubber and polybutadiene rubber are preferably used, and natural rubber is particularly preferably used. It is also effective to combine several rubber components such as a combination of natural rubber and styrene-butadiene copolymer rubber, a combination of natural rubber and polybutadiene rubber.

Examples of natural rubber include natural rubber of grades such as RSS # 1, RSS # 3, TSR20, and SIR20. As the epoxidized natural rubber, those having a degree of epoxidation of 10 to 60 mol% are preferable, and examples thereof include ENR25 and ENR50 manufactured by Kumpoulangrie. As the deproteinized natural rubber, a deproteinized natural rubber having a total nitrogen content of 0.3% by mass or less is preferable. As the modified natural rubber, a modified material containing a polar group obtained by reacting natural rubber with N, N-dialkylaminoethyl acrylate such as 4-vinylpyridine, N, N-diethylaminoethyl acrylate, 2-hydroxy acrylate or the like in advance. Natural rubber is preferably used.

Examples of the styrene-butadiene copolymer rubber (SBR) include emulsion polymerization SBR and solution polymerization SBR described on pages 210 to 211 of “Rubber Industry Handbook <Fourth Edition>” edited by the Japan Rubber Association. it can. Among these, it is particularly preferable to use solution polymerization SBR.
As a commercially available solution polymerized SBR, a solution polymerized SBR having a molecular terminal modified with 4,4′-bis- (dialkylamino) benzophenone such as “Nippol (registered trademark) NS116” manufactured by Nippon Zeon Co., Ltd., manufactured by JSR A solution-polymerized SBR having a molecular end modified with a tin halide compound such as “SL574” or a silane-modified solution-polymerized SBR such as “E10” or “E15” manufactured by Asahi Kasei Corporation is preferably used.
Further, any one of a silane compound such as a lactam compound, an amide compound, a urea compound, an N, N-dialkylacrylamide compound, an isocyanate compound, an imide compound, a trialkoxysilane compound having an alkoxy group, or an aminosilane compound is used alone. Alternatively, two or more different compounds such as a silane compound having a tin compound and an alkoxy group, and an alkylacrylamide compound and an silane compound having an alkoxy group are used, and the molecular ends are modified by nitrogen and tin at the molecular ends. In particular, solution polymerization SBR having any one of silicon, silicon, or a plurality of these elements is preferably used.

Examples of polybutadiene rubber (BR) include solution polymerization BR such as high cis BR with 90% or more of cis 1,4 bond and low cis BR with cis bond of around 35%, and low cis with high vinyl content. BR is preferably used. As a commercial product of BR, tin-modified BR such as “Nipol (registered trademark) BR 1250H” manufactured by Nippon Zeon is preferably used.
Also, 4,4′-bis- (dialkylamino) benzophenone, tin halide compound, lactam compound, amide compound, urea compound, N, N-dialkylacrylamide compound, isocyanate compound, imide compound, trialkoxy having an alkoxy group Two types of different compounds such as a silane compound such as a silane compound, an aminosilane compound alone, a silane compound having a tin compound and an alkoxy group, or a silane compound having an alkylacrylamide compound and an alkoxy group. In particular, solution polymerization BR having nitrogen, tin, silicon, or a plurality of these elements at the molecular ends obtained by modifying the molecular ends is particularly preferably used.
The rubber component (A) preferably contains natural rubber, and the above-mentioned BR is usually used by mixing with natural rubber. The proportion of natural rubber in the rubber component (A) is preferably 70% by mass or more.

<Resorcin resin>
The resorcin resin according to the present invention is not particularly limited as long as it is a resin containing resorcin as a constituent unit, but it is 20 to 80 mol% of resorcin as a constituent unit in all constituent units of the resorcin resin. The resin is preferably contained from the viewpoint of improving adhesiveness, and more preferably a resin containing resorcin as a constituent unit in an amount of 30 to 70 mol%.

(Cocondensate (B))
The resorcin resin according to the present invention includes a structural unit derived from p-tert-butylphenol represented by the following formula (1), a structural unit derived from o-phenylphenol represented by the following formula (2), and the following formula (3 It is preferable that it is a cocondensate (B) containing the structural unit derived from resorcin represented by this.
These structural units are usually contained in the main chain of the cocondensate, but may be contained in the side chain. Among these structural units, when the structural unit derived from o-phenylphenol (2) is not included, the softening point is high, and when blended with rubber during kneading, the kneading temperature is lower than the softening point May cause a problem of poor dispersibility, and may be unsuitable as an adhesive between rubber and a metal cord that is used by mixing with rubber during kneading. Moreover, when the structural unit (3) derived from resorcin is not contained, the ability as an adhesive between the rubber and the metal cord used by mixing with rubber during kneading is not sufficiently exhibited. Furthermore, when the structural unit (1) derived from p-tert-butylphenol is not included, the cost as a cocondensate becomes very high, and the cocondensate cannot be obtained industrially advantageously.

p-tert-octylphenol and p-nonylphenol are regarded as SVHC candidate substances stipulated in the REACH regulation, which is a regulation within the EU region, and their use in the EU region is likely to be restricted in the future.
Therefore, it is preferable to use an alternative compound not listed in the SVHC candidate substances defined in the REACH regulations.
Since the cocondensate (B) suitably used for the rubber composition according to the present invention does not contain p-tert-octylphenol and p-nonylphenol, there is no concern that it will be subject to REACH regulations in the future.

In the cocondensate (B) that can be used in the rubber composition according to the present invention, the content ratio of these structural units is o-phenylphenol with respect to 1 mole of the structural unit (1) derived from p-tert-butylphenol. The derived structural unit (2) is preferably 0.5 to 6 moles, more preferably 1.5 to 6 moles. When the amount is less than 0.5 times mol, the softening point may be too high and the above-mentioned problem may occur. When the amount is more than 6 times mol, the raw material cost of the cocondensate is increased, and the present invention is advantageous industrially. It may become impossible to produce the cocondensate according to.
The structural unit (3) derived from resorcin is usually 0.5 to 2 parts per 1 mol of the total amount of the structural unit (1) derived from p-tert-butylphenol and the structural unit (2) derived from o-phenylphenol. 0 times mole is contained. If the amount is less than 0.5 times mol, the ability to be used as an adhesive between the rubber and the metal cord used by blending with rubber during kneading may not be sufficiently exhibited. It may be difficult to manufacture.

In the cocondensate (B) that can be suitably used in the rubber composition according to the present invention, these structural units are usually bonded by a linking group such as an alkyl group and / or an alkyl ether group derived from an aldehyde used in the reaction. Is done. Among them, the linking group is preferably a methylene group and / or a dimethylene ether group derived from formaldehyde. The linking group is usually contained in an amount of 1 to 2 moles per 1 mole of the total amount of the structural unit (1) derived from p-tert-butylphenol and the structural unit (2) derived from o-phenylphenol.
The ratio of these structural units and bonding groups can be determined, for example, by analyzing the cocondensate using ¹ H-NMR. Specifically, a method is exemplified in which the cocondensate is analyzed by ¹ H-NMR, and among the obtained analysis results, the ratio is determined from the proton integral value derived from each structural unit or bonding group.
The cocondensate (B) that can be suitably used in the rubber composition according to the present invention contains a structural unit other than the structural units derived from p-tert-butylphenol, o-phenylphenol, and resorcin, if necessary. Can do. Examples of such structural units include structural units derived from various alkylphenols used as raw materials for cocondensates generally used as adhesives used in rubber processing steps.

The softening point of the cocondensate (B) according to the present invention is preferably 150 ° C. or lower. The softening point is more preferably in the range of 80 ° C. or higher and 150 ° C. or lower, further preferably in the range of 80 ° C. or higher and 140 ° C. or lower, and particularly preferably 90 ° C. or higher and 140 ° C. or lower.
If the softening point of the co-condensate (B) is higher than 150 ° C., a problem of poor dispersibility occurs when blended with the rubber composition during kneading in the rubber composition. It may become unsuitable as an adhesive between rubber and metal cord to be used. If it is lower than 80 ° C., blocking may occur during storage.

In the rubber composition according to the present invention, the cocondensate (B) is preferably contained in an amount of 0.1 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the rubber component (A).
If the compounding amount of the cocondensate (B) is 0.1 parts by mass or more with respect to 100 parts by mass of the rubber component (A), sufficient adhesiveness (particularly wet heat adhesiveness) can be obtained.
If the blending amount of the co-condensate (B) is 10 parts by mass or less with respect to 100 parts by mass of the rubber component (A), the adhesive reaction during vulcanization will not proceed excessively. It is possible to prevent a decrease in wet heat adhesion).
From the above viewpoint, the cocondensate (B) is more preferably 0.2 parts by mass or more and 8 parts by mass or less, and still more preferably 0.5 parts by mass with respect to 100 parts by mass of the rubber component (A). The amount is 6 parts by mass or less.

The total amount of unreacted monomers (free p-tert-butylphenol, o-phenylphenol and resorcin) and residual solvent contained in the cocondensate (B) is preferably 15% by mass or less. Odor can be reduced by setting it as 15 mass% or less, and it is preferable on working environment. In particular, the content of free resorcin is preferably 12% by mass or less. When the content of free resorcin is 12% by mass or less, when the cocondensate (B) is added to the rubber, the transpiration of resorcin that occurs during kneading into the rubber is improved, so that the working environment is greatly improved, which is particularly preferable. .
The total amount of unreacted monomers p-tert-butylphenol and o-phenylphenol other than free resorcin and residual solvent that may be used in the reaction contained in the cocondensate (B) is 5% by mass or less. Preferably there is. When the content is 5% by mass or less, odor is reduced and volatile organic compounds are reduced, which is preferable in the working environment, and further preferably 3% by mass or less. If the work environment is greatly improved, capital investment for work environment conservation is greatly reduced, which is very advantageous.
From the above viewpoint, the total amount of unreacted monomers other than free resorcin and the residual solvent contained in the rubber composition according to the present invention is preferably 0.20% by mass or less, and 0.17% by mass or less based on the rubber component. Further preferred.

<Filler>
A filler can be mix | blended with the rubber composition which concerns on this invention as needed. The filler is preferably at least one selected from carbon black and inorganic filler. In the present invention, carbon black is not included in the inorganic filler.
In the rubber composition according to the present invention, the total amount of carbon black and inorganic filler is preferably 5 parts by mass or more and 100 parts by mass or less with respect to 100 parts by mass of the rubber component (A). If it is 5 parts by mass or more, it is preferable from the viewpoint of securing the elastic modulus, and if it is 100 parts by mass or less, it is preferable from the viewpoint of improving low heat generation. From the above viewpoint, the total amount of carbon black and inorganic filler is more preferably 20 parts by mass or more and 80 parts by mass or less, and still more preferably rubber component (A) with respect to 100 parts by mass of rubber component (A). ) 20 parts by mass or more and 70 parts by mass or less, and particularly preferably 30 parts by mass or more and 70 parts by mass or less with respect to 100 parts by mass.

<Carbon black>
By containing carbon black, the rubber composition according to the present invention can enjoy the effect of reducing electrical resistance and suppressing charging. Examples of carbon black include high, medium or low structure SAF, ISAF, IISAF, N339, HAF, FEF, GPF, SRF grade carbon black, especially SAF, ISAF, IISAF, N339, HAF, FEF grade carbon black. Is preferably used. The nitrogen adsorption specific surface area (measured in accordance with N ₂ SA, JIS K 6217-2: 2001) of carbon black is preferably 30 to 250 m ² / g. Carbon black may be used individually by 1 type from what was mentioned above, and may be used in combination of 2 or more type.

<Inorganic filler>
If necessary, the inorganic filler used in the rubber composition according to the present invention is preferably at least one selected from silica and an inorganic compound represented by the following general formula (I).
dM ¹ · xSiO _y · zH ₂ O (I)
Here, in the general formula (I), M ¹ is a metal selected from the group consisting of aluminum, magnesium, titanium, calcium, and zirconium, an oxide or hydroxide of these metals, and a hydrate thereof. Or at least one selected from carbonates of these metals, and d, x, y and z are each an integer of 1 to 5, an integer of 0 to 10, an integer of 2 to 5, and an integer of 0 to 10 is there.
In the general formula (I), when both x and z are 0, the inorganic compound is at least one metal, metal oxide or metal hydroxide selected from aluminum, magnesium, titanium, calcium and zirconium. It becomes.

In the present invention, the above-mentioned inorganic filler is preferably silica from the viewpoint of achieving both low rolling properties and wear resistance.
The BET specific surface area (measured according to ISO 5794/1) of silica is preferably 40 to 350 m ² / g. Silica having a BET surface area within this range has an advantage that both rubber reinforcement and dispersibility in the rubber component (A) can be achieved. From this viewpoint, silica having a BET surface area in the range of 80 to 350 m ² / g is more preferable, and silica having a BET surface area in the range of 120 to 350 m ² / g is particularly preferable.
Commercially available products can be used as silica, and wet silica, dry silica, and colloidal silica are particularly preferable, and wet silica is particularly preferable.
Examples of such silica include “Ultra Gil (registered trademark) VN3” (BET specific surface area = 175 m ² / g) manufactured by Degussa, “Ultra Gil (registered trademark) 360”, “Ultra Gil (registered trademark) 7000”. "Zeosil (registered trademark) 115GR", "Zeosil (registered trademark) 1115MP", "Zeosil (registered trademark) 1205MP", "Zeosil (registered trademark) Z85MP" manufactured by Rhodia, "Nipseal" manufactured by Tosoh Silica Corporation Commercially available products such as “(registered trademark) AQ” are preferably used.

As the inorganic compound represented by the general formula (I), .gamma.-alumina, alpha-alumina, such as alumina _(Al _{2 O} 3), boehmite, alumina monohydrate such as diaspore _{_{_{(Al 2 O 3 · H 2}}} O ), Aluminum hydroxide such as gibbsite, bayerite [Al (OH) ₃ ], aluminum carbonate [Al ₂ (CO ₃ ) ₃ ], magnesium hydroxide [Mg (OH) ₂ ], magnesium oxide (MgO), magnesium carbonate (MgCO ₃ ), talc (3MgO · 4SiO ₂ · H ₂ O), attapulgite (5MgO · 8SiO ₂ · 9H ₂ O), titanium white (TiO ₂ ), titanium black (TiO _2n-1 ), calcium oxide (CaO) , calcium hydroxide [Ca _(OH) 2], magnesium aluminum oxide _{_{(MgO · Al 2 O 3)}} , clay _(Al 2 O · 2SiO _2), kaolin _{_{_{(Al 2 O 3 · 2SiO 2}}} · 2H 2 O), pyrophyllite _{_{_{(Al 2 O 3 · 4SiO 2}}} · H 2 O), bentonite _{_{_{(Al 2 O 3 · 4SiO 2}}} · 2H 2 O ), Aluminum silicate (Al ₂ SiO ₅ , Al ₄ .3SiO ₄ .5H ₂ O, etc.), magnesium silicate (Mg ₂ SiO ₄ , MgSiO ₃ etc.), calcium silicate (Ca ₂ SiO ₄ etc.), silicic acid Aluminum calcium (Al ₂ O ₃ · CaO · 2SiO ₂ etc.), magnesium calcium silicate (CaMgSiO ₄ ), calcium carbonate (CaCO ₃ ), zirconium oxide (ZrO ₂ ), zirconium hydroxide [ZrO (OH) ₂ · nH ₂ O], zirconium carbonate _{_{[Zr (CO 3) 2]}} , hydrogen to correct electric charge as various zeolites Such as an alkali metal or crystalline aluminosilicates containing alkali earth metals can be used.
Further, it is preferable that M ¹ in the general formula (I) is at least one selected from aluminum metal, aluminum oxide or hydroxide, and hydrates thereof, or aluminum carbonate. More preferred is aluminum oxide.
Examples of the aluminum hydroxide that can be blended in the rubber composition according to the present invention include aluminum hydroxide having a nitrogen adsorption specific surface area of 5 to 250 m ² / g and a DOP oil supply amount of 50 to 100 ml / 100 g.
These inorganic compounds represented by general formula (I) may be used alone or in combination of two or more. The average particle size of these inorganic compounds is preferably in the range of 0.01 to 10 μm, and more preferably in the range of 0.05 to 5 μm, from the viewpoint of kneading workability, wear resistance and wet grip performance balance.
The inorganic filler in the present invention may be used alone or in combination with silica and one or more inorganic compounds represented by the general formula (I).

<Silane coupling agent>
In the rubber composition according to the present invention, when an inorganic filler containing silica is blended, a silane coupling agent can be blended for the purpose of further improving the reinforcing property and low fuel consumption of the rubber composition. .
Examples of silane coupling agents include bis (3-triethoxysilylpropyl) tetrasulfide, bis (3-triethoxysilylpropyl) trisulfide, bis (3-triethoxysilylpropyl) disulfide, and bis (2-triethoxysilyl). Ethyl) tetrasulfide, bis (3-trimethoxysilylpropyl) tetrasulfide, bis (2-trimethoxysilylethyl) tetrasulfide, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 2-mercaptoethyltri Methoxysilane, 2-mercaptoethyltriethoxysilane, 3-trimethoxysilylpropyl-N, N-dimethylthiocarbamoyl tetrasulfide, 3-triethoxysilylpropyl-N, N-dimethylthiocarba Yl tetrasulfide, 2-triethoxysilylethyl-N, N-dimethylthiocarbamoyl tetrasulfide, 3-trimethoxysilylpropylbenzothiazolyl tetrasulfide, 3-triethoxysilylpropylbenzoyltetrasulfide, 3-triethoxy Silylpropyl methacrylate monosulfide, 3-trimethoxysilylpropyl methacrylate monosulfide, bis (3-diethoxymethylsilylpropyl) tetrasulfide, 3-mercaptopropyldimethoxymethylsilane, dimethoxymethylsilylpropyl-N, N-dimethylthiocarbamoyltetra Sulfide, dimethoxymethylsilylpropylbenzothiazolyl tetrasulfide, 3-octanoylthiopropyltriethoxysilane, etc. Among them, bis (3-triethoxysilylpropyl) polysulfide, 3-octanoylthiopropyltriethoxysilane and 3-trimethoxysilylpropylbenzothiazyl tetrasulfide are preferable from the viewpoint of improving the reinforcing property. .
One of these silane coupling agents may be used alone, or two or more thereof may be used in combination.

From the viewpoint of the effect as a coupling agent and prevention of gelation, the preferable blending amount of this silane coupling agent is such that the mass ratio (silane coupling agent / silica) is (1/100) to (20/100). It is preferable. If it is (1/100) or more, the effect of improving the low heat build-up of the rubber composition will be more suitably exhibited. If it is (20/100) or less, the cost of the rubber composition will be reduced, and the economic efficiency will be reduced. This is because it improves. Further, a mass ratio (3/100) to (20/100) is more preferable, and a mass ratio (4/100) to (10/100) is particularly preferable.

<Methylene donor compound>
Examples of methylene donor compounds that can be blended in the rubber composition according to the present invention include hexakis (methoxymethyl) melamine (HMMM), modified etherified methylolmelamine resin, hexamethylenetetramine (HMT), pentakis (methoxymethyl) methylolmelamine, and tetrakis. Examples include (methoxymethyl) dimethylolmelamine, which are usually used in the rubber industry. Among them, hexakis (methoxymethyl) melamine alone, modified etherified methylolmelamine resin alone or a mixture containing them as a main component is preferable. These methylene donor compounds can be used alone or in combination of two or more, and the blending amount thereof is in the range of about 0.5 to 4 parts by mass with respect to 100 parts by mass of the rubber component (A). A range of about 1 to 3 parts by mass is more preferable.

<Organic cobalt compounds>
Examples of the organic cobalt compound that can be blended in the rubber composition according to the present invention include acid cobalt salts such as cobalt versatate, cobalt neodecanoate, cobalt rosinate, cobalt naphthenate, and cobalt stearate, and fatty acid cobalt / boron complexes. Examples thereof include compounds (for example, trade name “Manobond C (registered trademark)” manufactured by Rhodia). The amount of the organic cobalt compound used is preferably in the range of 0.05 to 0.4 parts by mass in terms of cobalt content with respect to 100 parts by mass of the rubber component (A).

<Hydrocarbon resin>
If necessary, the rubber composition according to this embodiment includes one type from an alicyclic hydrocarbon resin, an aliphatic hydrocarbon resin, and an aromatic hydrocarbon resin in addition to the cocondensate (B). You may mix | blend the hydrocarbon resin chosen above. Here, the alicyclic hydrocarbon resin refers to a petroleum resin produced mainly from cyclopentadiene and / or dicyclopentadiene obtained by dimerizing cyclopentadiene extracted from a C5 fraction of petroleum. An aliphatic hydrocarbon resin refers to a petroleum resin produced using a C5 fraction of petroleum as a main raw material, and an aliphatic hydrocarbon resin refers to a petroleum produced using a C9 fraction of petroleum as a main raw material. Refers to resin.
Of these hydrocarbon resins, a dicyclopentadiene resin (DCPD resin) produced from a high-purity dicyclopentadiene obtained by dimerizing cyclopentadiene as a main raw material is preferable from the viewpoint of enhancing rubber reinforcement.
Preferred examples of the dicyclopentadiene resin include quinton 1000 series (Quinton 1105, quinton 1325, quinton 1340) manufactured by Nippon Zeon Co., Ltd.

<Other additives>
In the rubber composition according to the present invention, various chemicals commonly used in the rubber industry, for example, a vulcanizing agent, a vulcanization accelerator, a vulcanization retarder, as desired, as long as the effects of the present invention are not impaired. Process oil, anti-aging agent, zinc white, stearic acid, etc. can be blended.
(Vulcanizing agent)
Examples of the vulcanizing agent that can be blended in the rubber composition according to the present invention include sulfur. Examples of the sulfur component include powdered sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, and highly dispersible sulfur. Usually powdered sulfur is preferred.
The amount of the vulcanizing agent used is preferably 0.1 parts by mass or more and 10 parts by mass or less, more preferably 1.0 part by mass or more and 8.0 parts by mass or less as a sulfur content with respect to 100 parts by mass of the rubber component (A). It is. If the amount is less than 0.1 parts by mass, the rupture strength, wear resistance, and fuel efficiency of the vulcanized rubber may be reduced. If the amount exceeds 10 parts by mass, the rubber elasticity is lost.

(Vulcanization accelerator)
Vulcanization accelerators that can be blended in the rubber composition according to the present invention are described in pages 412 to 413 of the Rubber Industry Handbook <Fourth Edition> (issued by the Japan Rubber Association on January 20, 1994). Examples thereof include thiazole vulcanization accelerators, sulfenamide vulcanization accelerators, and guanidine vulcanization accelerators. Among these, for example, N-cyclohexyl-2-benzothiazolylsulfenamide (CBS), N-tert-butyl-2-benzothiazolylsulfenamide (BBS), N, N-dicyclohexyl-2 -Benzothiazolylsulfenamide (DCBS), 2-mercaptobenzothiazole (MBT), dibenzothiazyl disulfide (MBTS), diphenylguanidine (DPG).
Among them, N-cyclohexyl-2-benzothiazolylsulfenamide (CBS), N-tert-butyl-2-benzothiazolylsulfenamide (BBS), N, N-dicyclohexyl-2-benzothiazolylsulfur It is preferable to use phenamide (DCBS) or dibenzothiazyl disulfide (MBTS) and diphenylguanidine (DPG) in combination.
The amount of the vulcanization accelerator used is not particularly limited, but is preferably in the range of 0.5 to 3 parts by mass per 100 parts by mass of the rubber component (A). In particular, the range of 0.5 to 1.5 parts by mass is particularly preferable. The amount of zinc oxide used is not particularly limited, but is preferably in the range of 3 to 15 parts by mass per 100 parts by mass of the rubber component (A). In particular, the range of 5 to 10 parts by mass is particularly preferable.

(Vulcanization retarder)
Examples of the vulcanization retarder that can be blended in the rubber composition according to the present invention include phthalic anhydride, benzoic acid, salicylic acid, N-nitrosodiphenylamine, N- (cyclohexylthio) -phthalimide (CTP), sulfonamide derivatives, diphenylurea And bis (tridecyl) pentaerythritol-diphosphite and the like, and N- (cyclohexylthio) -phthalimide (CTP) is preferably used.
(Process oil)
As the process oil used as a softening agent that can be blended in the rubber composition according to the present invention, an aromatic oil is used from the viewpoint of compatibility with SBR. In addition, naphthenic oil or paraffinic oil is used from the viewpoint of emphasizing low temperature characteristics. The amount used is preferably 0 to 100 parts by mass with respect to 100 parts by mass of the rubber component (A). If the amount is 100 parts by mass or less, the tensile strength and low fuel consumption (low heat generation) of the vulcanized rubber are deteriorated. Can be suppressed.

(Anti-aging agent)
Antiaging agents that can be blended in the rubber composition according to the present invention include those described on pages 436 to 443 of “Rubber Industry Handbook <Fourth Edition>” edited by the Japan Rubber Association. Among these, for example, 3C (N-isopropyl-N′-phenyl-p-phenylenediamine), 6C [N- (1,3-dimethylbutyl) -N′-phenyl-p-phenylenediamine], RD or 224 (2,2,4-trimethyl-1,2-dihydroquinoline polymer), AW (6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline), high-temperature condensate of diphenylamine and acetone, etc. Can be mentioned.
The amount used is preferably 0.1 to 5.0 parts by weight, more preferably 0.3 to 3.0 parts by weight, per 100 parts by weight of the rubber component (A).
(Organic acid)
Examples of organic acids that can be used in the rubber composition according to the present invention include stearic acid, palmitic acid, myristic acid, lauric acid, arachidic acid, behenic acid, lignoceric acid, capric acid, pelargonic acid, caprylic acid, and enanthic acid. And saturated fatty acids such as caproic acid, oleic acid, vaccenic acid, linoleic acid, linolenic acid, and nervonic acid, and resin acids such as rosin acid and modified rosin acid.
In the method for producing a rubber composition according to the present invention, among the organic acids, 50 mol% or more in the organic acid is stearic acid because it is necessary to sufficiently function as a vulcanization acceleration aid. It is preferable. 50 mol% or less in the organic acid may be rosin acid (including modified rosin acid) and / or fatty acid contained when the styrene-butadiene copolymer is prepared by emulsion polymerization.

[Method for Producing Cocondensate (B)]
The method for producing a cocondensate according to the present invention includes the following steps in the following order.
(A) A step of reacting a mixture of p-tert-butylphenol and o-phenylphenol with formaldehyde in the presence of an alkali to obtain a resol-type condensate.
(B) a step of further reacting 0.8 times mol or more of resorcin with respect to the total amount of p-tert-butylphenol and o-phenylphenol.

The ratio of o-phenylphenol in the mixture of p-tert-butylphenol and o-phenylphenol used in step (a) (hereinafter, these two types of phenols may be collectively referred to as “phenol derivatives”) is particularly Although not limited, it is preferably 35 mol% to 85 mol%, more preferably 40 mol% to 85 mol%, and further preferably 60 mol% to 85 mol%, based on the total amount of the phenol derivative. preferable. If it is less than 35 mol%, the softening point of the resulting cocondensate will be high, and dispersion may be poor when kneaded with the rubber component (A). If it exceeds 85 mol%, a large amount of expensive o-phenylphenol is required, and it may be impossible to produce a cocondensate in an industrially advantageous manner. In addition, the mixture of p-tert-butylphenol and o-phenylphenol in the present invention is a mixture mixed in advance before being charged into the reactor, and separately charged into the reactor, resulting in the mixture in the reactor. Also included are.

As the formaldehyde used in the step (a), in addition to formaldehyde itself, a formalin that is an aqueous solution, or a compound that easily generates formaldehyde such as paraformaldehyde or trioxane can be used. The molar ratio of formaldehyde charged is not particularly limited, but it is preferably 1 to 3 times by mole, more preferably 1.5 to 2.5 times by mole, based on the total amount of phenol derivatives. When the amount is less than 1 mole, unreacted monomers may increase and odor and volatile organic compounds may increase. Further, when the amount is more than 3 times mole, a large amount of formaldehyde remains unreacted, so that the resin may have a three-dimensional structure and the softening point may be increased.

As the alkali, in addition to hydroxides or carbonates of alkali metals or alkaline earth metals, those used for producing ordinary resol-type condensates such as ammonia and amines can be used. Specific examples of the alkali metal or alkaline earth metal hydroxide or carbonate include sodium hydroxide, potassium hydroxide, calcium hydroxide, sodium carbonate, and potassium carbonate. Among these, sodium hydroxide and potassium hydroxide are preferable. These alkalis can be used in the form of a solid or an aqueous solution, but it is preferable to use an aqueous solution in terms of reactivity and handling. When an aqueous solution is used, the concentration is usually 10% by mass to 50% by mass. The alkali charge molar ratio is not particularly limited, but is preferably in the range of 0.03 to 0.6 times mol, more preferably in the range of 0.03 to 0.3 times mol with respect to the total amount of the phenol derivative.

The reaction of step (a), that is, the reaction of a mixture of p-tert-butylphenol and o-phenylphenol with formaldehyde in the presence of an alkali can also be carried out in a solvent. The solvent to be used is not particularly limited, and water, alcohol, aromatic hydrocarbon and the like can be used. More specifically, water, methanol, ethanol, propanol, butanol, toluene, xylene, ethylbenzene, cumene, monochlorobenzene and the like are exemplified. Of these, water, toluene, and xylene are preferable. These solvents can be used alone or in combination of two or more. When a solvent is used, it is usually used in an amount of 0.4 to 4 times (for example, 0.4 to 2 times) the total amount of phenol derivatives. The reaction in the step (a) is usually carried out at a reaction temperature of 40 to 100 ° C. and a reaction time of 1 to 48 hours (eg 1 to 8 hours).

The resol-type condensate obtained by such a reaction may be used as it is in the reaction of step (b) without neutralizing the used alkali, that is, the reaction with resorcin, or by adding an acid to neutralize the alkali. It may be used after being summed. The type of acid used for neutralization is not particularly limited, and examples include hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, formic acid, acetic acid, oxalic acid, p-toluenesulfonic acid, and the like. These acids may be used alone or in combination of two or more. At this time, the total amount of the acid used is not particularly limited, but it is preferable to use an equivalent amount (based on the amount of substance) of the acid that is normally used. In addition, in order to remove unreacted formaldehyde and inorganic salts generated by neutralization, a resol-type condensate may be extracted and washed using an organic solvent that is not miscible with water as necessary. Good.

In the step (b), the charged molar ratio of resorcin when reacting the obtained resole-type condensate with resorcin is preferably 0.5 times mol or more, more preferably 0 with respect to the total amount of phenol derivatives. The amount is from 0.8 to 4.0 times mol, more preferably from 0.8 to 2.0 times mol, particularly preferably from 1.0 to 2.0 times mol. If it is more than 4.0 moles, volatility may be a problem because a large amount of unreacted resorcin remains. If it is lower than 0.5 mol, the reaction will not be completed and the original performance will not be achieved, or the reaction between resol-type condensates will proceed preferentially, and the resulting cocondensate will be polymerized, resulting in a softening point. May not be 150 ° C. or lower.

Although the reaction between the resole-type condensate and resorcin can be carried out without using a solvent, the presence of a solvent more than 0.2 mass times the total amount of p-tert-butylphenol and o-phenylphenol When carried out below, free resorcin can be reduced to 12% by mass or less, which is preferable. More preferably, the reaction is carried out in the presence of 0.4 to 4.0 times by mass, particularly preferably 0.4 to 2.0 times by mass of solvent with respect to the total amount of p-tert-butylphenol and o-phenylphenol. If less than 0.2 mass times, the reaction between resole-type condensates may proceed preferentially over the reaction between resorcin and resole-type condensates, and the resulting cocondensate may be polymerized, Free resorcin cannot be reduced to 12% by mass or less. In addition, the reaction proceeds even when used in an amount of 4.0 mass times or more, but the volumetric efficiency is lowered and the cocondensate cannot be produced economically advantageously.

The usable solvent is not particularly limited, and examples thereof include alcohols, ketones, and aromatic hydrocarbons. More specifically, methanol, ethanol, propanol, butanol, methyl isobutyl ketone, diisobutyl ketone, cyclohexanone, toluene, xylene, ethylbenzene, cumene, monochlorobenzene and the like are exemplified. Among these, ketones and aromatic hydrocarbons are preferable, and methyl isobutyl ketone, toluene, and xylene are more preferable. These solvents can be used alone or in combination of two or more as required. Moreover, the solvent used when manufacturing a resol type condensate may be used for this solvent as it is, and a new solvent may be added suitably.

The reaction between the resole-type condensate and resorcin is not particularly limited, but is usually carried out at a reaction temperature of 40 to 150 ° C. and a reaction time of 1 to 48 hours (eg, 1 to 8 hours).
In order to reduce the content of free resorcin contained in the cocondensate to 12% by mass or less, before carrying out the solvent removal step described later, the content of free resorcin is 120 ° C. or higher until the content of free resorcin in the reaction mixture becomes 12% by mass or less It is preferable to carry out the reaction. If more than 12% by mass of free resorcin remains in this reaction stage, it is difficult to implement industrially at a high temperature and a high degree of vacuum even if it is attempted to remove free resorcin at the same time until it becomes less than 12% by mass in the solvent removal step described later. Conditions are necessary, and the cocondensate obtained at this time is colored by heat or polymerization proceeds. As a result, the softening point exceeds 150 ° C., and is used by blending with rubber during kneading. Unsuitable as an adhesive between rubber and metal cord.
The reaction is performed at 120 ° C or higher as long as it is 120 ° C or higher at any time during the reaction. For example, the reaction is started at less than 120 ° C in the initial stage of reaction, and then gradually heated to 120 ° C or higher. The method etc. which are made are illustrated. If the reaction temperature never exceeds 120 ° C., free resorcin in the reaction mixture does not become 12% by mass or less. In addition, as described above, when this reaction is carried out in the absence of a solvent of 0.2 mass times or more, the resulting cocondensate is polymerized, or the free resorcin content is not 12 mass% or less. The reaction mixture refers to everything contained in the reaction vessel, such as resole-type condensate, resorcin, solvent, etc., which are the raw materials for this reaction, and the resorcin content in the reaction mixture can be quantified by analysis using, for example, a gas chromatograph. is there. In order to reduce the free resorcin content, a method of simply reducing the amount of raw material resorcin used is also conceivable. However, when produced by this method, the raw material resorcin is insufficient during the reaction, and instead, the resorcin site in the cocondensate is further increased. Since it reacts and polymerizes, the softening point becomes very high.

In the reaction between the resole-type condensate and resorcin in step (b), the reaction rate tends to be slow if water is present in the system, and the reaction rate is reduced by the water generated by the reaction between the resole-type condensate and resorcin. Therefore, it is preferable to carry out the reaction while dehydrating for the purpose of promoting the reaction. In addition, in this dehydration reaction, water generated in the reaction is sufficiently dehydrated, so that it is dehydrated under reduced pressure at the beginning of the reaction, and then the internal temperature is set to 120 ° C. or higher. Is preferred.
When a solvent is used for the reaction between the resole-type condensate and resorcin, the solvent used in the reaction is usually removed after the reaction. The conditions for removing the solvent are not particularly limited. For example, the solvent removal is performed at 120 to 160 ° C. under a reduced pressure of 45 to 10 kPa. Although it is possible to reduce the free resorcin content to some extent by this removal operation, when the free resorcin content in the reaction mixture before solvent removal is more than 12% by mass, the free resorcin content of the cocondensate after solvent removal is reduced. In order to make it 12% by mass or less, high temperature and high pressure reduction conditions that are difficult to implement industrially are necessary, and the cocondensate obtained at this time is colored by heat, thereby reducing the product value. is there.

[Preparation of rubber composition]
The rubber composition according to the present invention can be obtained by kneading the various components and additives described above using a kneader such as an open kneader such as a roll or a closed kneader such as a Banbury mixer.
That is, the rubber composition according to the present invention is the first stage of kneading, and after kneading the rubber component (A), the cocondensate (B), and a filler as necessary, in the final stage of kneading, It can be prepared by mixing a vulcanizing agent, a vulcanization accelerator, a methylene donor compound, and other compounding agents as required.

[Metal cord]
The metal cord according to the present invention is a metal cord made of a single wire of steel wire with brass plating applied to the peripheral surface or a metal cord made by twisting the steel wire. The metal cord according to the present invention is a ternary or quaternary plating in which brass plating is 58 to 70% by mass of Cu, 0.5 to 10% by mass of at least one metal selected from Co and Ni, and the balance is Zn. . In the case of a combination of three kinds of metals of Cu (copper), Zn (zinc) and Co (cobalt) or Ni (nickel), it becomes ternary plating, and Cu (copper), Zn (zinc) and Co (cobalt) In the case of a combination of four metals with Ni (nickel), quaternary plating is performed. For example, after adjusting the mass ratio of Cu (copper), Zn (zinc), Co (cobalt) and / or Ni (nickel), the adjusted mass is applied to steel wires in the order of Cu, Zn, Ni, Co. Repeated plating or, in some cases, repeated plating on steel wire in the order of Cu, Zn, Co, Ni, and then thermally diffused at 450-550 ° C. for 3-6 seconds to obtain the desired ternary or quaternary plating .
In the composition of brass plating, if Cu is 58% by mass or more, the wire drawing property is improved and disconnection hardly occurs, and the productivity is improved. On the other hand, if Cu is 70 mass% or less, wet heat adhesiveness will be improved and sufficient durability can be enjoyed with respect to the environment to which the tire is exposed. When Co and / or Ni is in the range of 0.5 to 10% by mass, the initial adhesiveness and wet heat adhesiveness with the rubber composition are preferably improved.

The average thickness of the brass plating layer is preferably 0.13 to 0.35 μm, and more preferably 0.13 to 0.30 μm. If the average thickness of the brass plating layer is 0.13 μm or more, the portion where the iron base is exposed is reduced and the initial adhesiveness is improved. On the other hand, if it is 0.35 μm or less, it is excessive due to heat during use of the rubber article. It is possible to obtain a stronger bond by suppressing the progress of the adhesion reaction.

Furthermore, the diameter of the steel wire is preferably 0.60 mm or less, and more preferably 0.40 mm or less. When the diameter is 0.60 mm or less, the surface strain is reduced when the used rubber article is repeatedly strained under bending deformation, so that it is difficult to cause buckling.

[Production of pneumatic tires]
After the rubber cord according to the present invention is coated on the metal cord according to the present invention to form a metal cord-rubber composite, it is pasted and molded by a normal method on a tire molding machine to form a raw tire. . After forming the green tire, the green tire is heated and pressurized in a vulcanizer and vulcanized to produce a tire having the metal cord-rubber composite according to the present invention.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

[Method for evaluating cocondensate]
Analysis and physical property evaluation of the co-condensate were performed as follows.
(A) Measurement of average molecular weight of cocondensate The average molecular weight of the cocondensate was calculated as a polystyrene-converted weight average molecular weight by gel permeation chromatography (GPC) analyzed under the following apparatus and conditions.
-Equipment used: HLC-8220GPC (manufactured by Tosoh Corporation),
Column: TSK guard column SUPER HZ-L (manufactured by Tosoh Corporation)
+ TSK-GEL SUPER HZ1000 (4.6mmφ × 150mm)
+ TSK-GEL SUPER HZ2500 (4.6mmφ × 150mm)
+ TSK-GEL SUPER HZ4000 (4.6 mmφ × 150 mm),
Column temperature: 40 ° C
-Injection volume: 10 μL,
Carrier and flow rate: tetrahydrofuran 0.35 mL / min,
Sample preparation: About 0.02 g of the cocondensate is dissolved in 20 mL of tetrahydrofuran.

(B) Measurement of residual monomer and residual solvent The residual monomer and residual solvent were quantified by gas chromatography based on the following conditions.
-Equipment used: Gas chromatograph GC-14B manufactured by Shimadzu Corporation
Column: Glass column outer diameter 5 mm x inner diameter 3.2 mm x length 3.1 m,
Filler: Filler Silicone OV-17 10% Chromosorb WHP 80/100 mesh, max. temp. 340 ° C,
Column temperature: 80 ° C. → 280 ° C.
・ Vaporization chamber temperature: 250 ℃
-Detector temperature: 280 ° C
・ Detector: FID,
・ Carrier: N ₂ (40 ml / min),
Combustion gas: hydrogen (60 kPa), air (60 kPa),
-Injection volume: 2 μL.
About 0.5 g of the cocondensate and 0.05 g of anisole as an internal standard were dissolved in 10 mL of acetone and analyzed under the above conditions. Residual solvent and residual monomer contents (%) in the cocondensate were measured by an internal standard method (GC-IS method). In addition, content (%) described in the text of Examples and Comparative Examples is expressed as mass percent unless otherwise specified.

(C) Measurement of softening point It was measured by a method based on JIS-K2207-1996 (ring and ball method).
(D) Content ratio of each structural unit in the cocondensate ¹ H-NMR analysis was performed by a method based on the following conditions.
・ Equipment: “JMN-ECS” (400 MHz) manufactured by JEOL Ltd.
Solvent: deuterium substituted dimethyl sulfoxide.
-Chemical shift of each component: Tetramethylsilane was used as a reference (0 ppm), and the peak indicated by the following values was defined as the peak of each component.
P-tert-Butylphenol-derived p-tert-butyl group proton: 1.0 to 1.2 ppm, formaldehyde-derived methylene group proton: 3.4 to 3.9 ppm, o-phenylphenol-derived o-phenyl Group proton: 7.1-7.5 ppm.
In addition, about the component ratio in a following example and a comparative example, it is a ratio based on the following references | standards.
o-Phenylphenol: Ratio when p-tert-butylphenol is 1 (mole times), methylene group derived from formaldehyde: Ratio to the total amount of o-phenylphenol and p-tert-butylphenol (mole times).

[Production Example of Cocondensate (B)]
Production Example 1
In a four-necked separable flask equipped with a reflux condenser and a thermometer, 97.3 g (1.2 mol) of formalin with a purity of 37%, 15.0 g (0.10 mol) of p-tert-butylphenol, 85 of o-phenylphenol 85 0.0 g (0.50 mol) and 75.4 g of toluene were sequentially added. Thereafter, the temperature was raised to an internal temperature of 45 ° C., 20 g (0.12 mol) of a 24% aqueous sodium hydroxide solution was added, and the mixture was stirred until the heat generation stopped. After confirming that the exotherm had subsided, the temperature was raised to an internal temperature of 65 ° C. and kept at that temperature for 2 hours. Thereafter, the temperature was raised again until the internal temperature reached 80 ° C., and the temperature was further kept for 4 hours.
After completion of the reaction, the reaction mixture was cooled to an internal temperature of 65 ° C. or less, neutralized by adding 49 g of water and 7.55 g (1.13 mol) of oxalic acid dihydrate, and 22.6 g of toluene was added, and then allowed to stand. And the aqueous layer was removed.
62.7 g (0.57 mol) of resorcin was added, the temperature was raised to an internal temperature of 70 ° C., and azeotropic dehydration was performed for 4 hours under reduced pressure. During this time, the internal temperature rose to 90 ° C. Subsequently, the temperature was raised to 115 ° C. at normal pressure, and azeotropic dehydration was performed for 1 hour. Thereafter, the temperature was raised to an internal temperature of 145 to 150 ° C., and the solvent toluene was distilled off by keeping the temperature for 2 hours. Thereafter, the pressure was reduced to 16 kPa while maintaining the internal temperature at 140 to 150 ° C., and the solvent toluene was further distilled off by maintaining the temperature for 2 hours. By the above operation, 177 g of orange cocondensate was obtained.
Average molecular weight of the cocondensate: 2160, softening point of the cocondensate: 123 ° C., residual toluene content in the cocondensate: 1.1%, residual p-tert-butylphenol content: 0.0%, residual o-phenyl Phenol content: 0.4%, Residual resorcin content: 9.5%. Ratio of each structural unit of the cocondensate: o-phenylphenol: 5.40, methylene group: 1.33.

The cocondensate (B) obtained in Production Example 1 was used as resorcin resin 1, and SUMIKANOL620 (manufactured by Taoka Chemical Co., Ltd.), which is a commercially available resin adhesive, was used as resorcin resin 2 as a conventional product. Table 1 shows the evaluation results of resorcin resins 1 and 2.
In Table 1, the free phenols represent the total amount of p-tert-butylphenol and o-phenylphenol in the case of Production Example 1 of the present application. In the case of SUMIKANOL620, it represents the total amount of p-tert-octylphenol and p-cresol.

[Production example of metal cord]
Production Examples 2 to 13
Repeated plating on a steel wire with a diameter of 1.7 mm in the order of Cu, Zn, Co, and Ni in the mass% of Cu, Zn, Ni, and Co shown in Table 2, followed by thermal diffusion treatment at 550 ° C. for 5 seconds. After obtaining the desired ternary or quaternary plating, wire drawing was performed to obtain a steel wire having a plating average thickness of 0.25 μm and a diameter of 0.30 mm. Using the obtained steel wires, 12 types of metal cords, which are twist cords having a structure of 1 × 3 × 0.30 (mm), were produced.
In addition, since the metal cord containing Co in the brass plating can remove or reduce the cobalt fatty acid salt of the coated rubber composition, it can improve the crack resistance after deterioration of the coated rubber composition. Can do.

Examples 1 to 11 and Comparative Examples 1 to 8
According to the formulation shown in Table 2 below, first, natural rubber, carbon black, resorcin resin 1 or 2 and cobalt fatty acid salt were kneaded with a Banbury mixer and discharged when the temperature reached 160 ° C. Next, an anti-aging agent, zinc oxide, insoluble sulfur, a vulcanization accelerator, and a methylene donor were added to and mixed with the obtained mixture by a 6-inch open roll made of Kansai Roll that was kept at 60 ° C., and a rubber composition for coating a metal cord A product was prepared. Details of each component in Table 2 are as follows. The unit of the numerical values in the formulation of Table 2 represents parts by mass. The workability of the seven types of unvulcanized rubber compositions obtained was evaluated. Subsequently, seven types of unvulcanized rubber compositions were vulcanized at 160 ° C. for 20 minutes, and the crack resistance after deterioration of each vulcanized rubber composition was evaluated. The results are shown in Table 2.
Next, both of the above-mentioned 12 types of metal cords arranged at intervals of 12.5 mm are attached to the respective unvulcanized rubber compositions (seven types of unvulcanized rubber compositions having the compounding formulations described in Table 2 below). 19 types of metal cord-rubber composites of Examples 1 to 11 and Comparative Examples 1 to 8 comprising combinations of the metal cords of Table 2 and rubber compositions. The body was made. The 19 kinds of obtained metal cord-rubber composites were evaluated for initial adhesion and wet heat adhesion. The results are shown in Table 2.

[Evaluation method of metal cord-rubber composite and vulcanized rubber composition]
(A) Initial adhesiveness Metal cords are arranged in parallel at an interval of 12.5 mm, the metal cords are covered with a rubber composition from above and below, and vulcanized at 160 ° C. for 7 minutes to obtain a rubber composition and a steel cord. Glued. In this way, a rubber-metal composite was obtained in which a metal cord was embedded in a rubber sheet having a thickness of 1 mm (the metal cord was at the center of the rubber sheet in the thickness direction and on the sheet surface at intervals of 12.5 mm. Are lined up). Thereafter, in accordance with ASTM D 2229-2004, the metal cord is pulled out from each sample immediately after vulcanization, and the coverage of the rubber adhering to the metal cord is determined by visual observation from 0 to 100%, and the initial adhesion It was used as an index of sex. The results were expressed as an index with Comparative Example 1 as 100. It shows that it is excellent in initial stage adhesiveness, so that an index value is large.
Initial adhesiveness index = {(Rubber coverage attached to metal cord of test sample) / (Rubber coverage attached to metal cord of sample of Comparative Example 1)} × 100
(B) Wet heat adhesion (adhesion after wet heat aging)
The metal cords were arranged in parallel at intervals of 12.5 mm, the metal cords were covered with the rubber composition from above and below, and vulcanized at 160 ° C. for 20 minutes to bond the rubber composition and the metal cord. In this way, a metal cord-rubber composite in which a metal cord was embedded between rubber sheets having a thickness of 1 mm was obtained (the metal cord was in the direction of the thickness center of the rubber sheet, parallel to the sheet surface, 12 .. arranged at intervals of 5 mm). After the metal cord-rubber composite was deteriorated for 10 days at 75 ° C. and 95% relative humidity, the metal cord was pulled out from each sample and adhered to the metal cord according to ASTM D 2229-2004. The rubber coverage was determined from 0 to 100% by visual observation and used as an indicator of thermal degradation. The results were expressed as an index with Comparative Example 1 as 100. It shows that it is excellent in wet heat adhesiveness, so that an index value is large. That is, it shows that it is excellent in resistance to thermal degradation.
Wet heat adhesion index = {(Rubber coverage attached to metal cord of test sample) / (Rubber coverage attached to metal cord of sample of Comparative Example 1)} × 100
(C) Crack growth resistance after deterioration The unvulcanized sample was vulcanized at 160 ° C. for 20 minutes to prepare vulcanized rubber samples having a thickness of 2 mm, and these samples were each deteriorated at 100 ° C. for 24 hours. . Thereafter, the sample was subjected to a constant stress fatigue test using a Ueshima fatigue tester, and the number of times until fracture was measured. The results were expressed as an index with Comparative Example 1 as 100. It shows that it is excellent in the crack progress property after deterioration, so that an index value is large.
Crack growth resistance index after degradation = {(number of times until the test sample is cut) / (number of times until the sample of Comparative Example 1 is cut)} × 100

(note)
* 1: Natural rubber: SMR-CV60,
* 2: Carbon black: “Seast 300” (HAF-LS grade) manufactured by Tokai Carbon Co., Ltd.
* 3: Resorcin resin 1: Cocondensate (B) obtained in Production Example 1 above
* 4: Resorcin resin 2: manufactured by Taoka Chemical Co., Ltd., trade name “SUMIKANOL620”
* 5: Cobalt fatty acid salt: cobalt stearate (reagent)
* 6: Zinc oxide: manufactured by Shodo Chemical Co., Ltd., trade name "Zinc oxide 2 types"
* 7: Anti-aging agent: N-phenyl-N ′-(1,3-dimethylbutyl) -p-phenylenediamine: manufactured by Ouchi Shinsei Chemical Co., Ltd., trade name “NOCRACK 6C”
* 8: Vulcanization accelerator: N, N-dicyclohexyl-2-benzothiazolylsulfenamide (reagent),
* 9: Insoluble sulfur: manufactured by Flexis, trade name “Christex HS OT-20”
* 10: Methylene donor compound: Modified etherified methylol melamine resin “Sumikanol 507AP” manufactured by Taoka Chemical Industries, Ltd.

As is apparent from Table 2, the metal cord-rubber composites of the present invention all had better initial adhesion and wet heat adhesion than the metal cord-rubber composites of Comparative Examples 1-8. . In addition, the metal cord-rubber composites using the rubber composition containing the cocondensate (B) according to the present invention are all wet-heat bonded as compared with the metal cord-rubber composites of Comparative Examples 1-8. Improved further. Furthermore, since the metal cord containing Co in the brass plating can remove the cobalt fatty acid salt of the coated rubber composition, the crack resistance after deterioration of the rubber composition of Example 4 that does not contain the cobalt fatty acid salt. Progressability has improved significantly.
Further, the rubber composition containing the cocondensate (B) suitably used as the resorcin resin according to the present invention has SVHC candidate substances stipulated in the REACH regulations as compared with the rubber composition of Example 5. Without fear of being subject to REACH regulations.
Further, the total amount of unreacted monomers other than free resorcin and the residual solvent contained in the rubber compositions according to Examples 1 to 4 and 8 to 10 was 0.03% by mass, 0.17% by mass with respect to the rubber component. % Of the unreacted monomer other than free resorcin and the residual solvent contained in the rubber composition containing the conventional product (SUMIKANOL 620) according to Example 5, compared with 0.246% by mass. Odor generation during kneading of the vulcanized rubber composition has been greatly reduced, and capital investment for work environment conservation has been greatly reduced.

The metal cord-rubber composite of the present invention is suitable as a reinforcing material for rubber articles, particularly tire carcasses and belts. In particular, when the metal cord-rubber composite of the present invention is applied to a belt of a tire for trucks and buses, a tire for a passenger car, particularly a radial tire for a passenger car, the adhesion speed with the rubber is increased, so that An effect that the vulcanization time can be greatly shortened can also be obtained. On the other hand, when applied to the carcass of truck and bus tires, especially truck and bus radial tires, the speed of adhesion to rubber increases at the bead part, so that the bead part durability is shortened along with shortening of the vulcanization time. It is also possible to improve.

Claims

A metal cord-rubber composite formed by coating a rubber composition on a metal cord made of a single wire of steel wire having brass plating applied to its peripheral surface or a metal cord formed by twisting the steel wire, the rubber composition The rubber component (A) and 100 parts by mass of the rubber component (A) are mixed with 0.1 to 10 parts by mass of a resorcin resin, and the brass plating is composed of 58 to 70% by mass of Cu, Co and Ni. A metal cord-rubber composite, characterized in that it is a ternary or quaternary plating comprising 0.5 to 10% by mass of at least one selected metal and the balance being Zn.
The resorcin resin is represented by a structural unit derived from p-tert-butylphenol represented by the following formula (1), a structural unit derived from o-phenylphenol represented by the following formula (2), and the following formula (3). The metal cord-rubber composite according to claim 1, which is a cocondensate (B) containing a structural unit derived from resorcin and having a softening point of 150 ° C or lower.
The metal cord-rubber composite according to claim 2, wherein the softening point of the cocondensate (B) is 80 ° C or higher and 150 ° C or lower.
The metal cord-rubber composite according to claim 2 or 3, wherein the softening point of the cocondensate (B) is 80 ° C or higher and 140 ° C or lower.
The metal cord-rubber composite according to any one of claims 1 to 4, wherein an average thickness of the brass plating is 0.13 to 0.35 µm.