JP6820181B2 - Tire member manufacturing method and tire manufacturing method - Google Patents

Description

The present disclosure relates to a method for manufacturing a tire member and a method for manufacturing a tire.

Patent Document 1 describes a method in which (2Z) -4-[(4-aminophenyl) amino] -4-oxo-2-sodium butenoate and carbon black are put into a Banbury mixer and kneaded into rubber (hereinafter, "preceding"). "Manufacturing method") is disclosed. For (2Z) -4-[(4-aminophenyl) amino] -4-oxo-2-butenoate, the terminal nitrogen functional group is bonded to carbon black, and the carbon-carbon double bond portion is the polymer. Patent Document 1 further discloses that they are combined.

Japanese Unexamined Patent Publication No. 2014-95020

（式（Ｉ）において、Ｒ^１およびＲ^２は、水素原子、炭素数１〜２０のアルキル基、炭素数１〜２０のアルケニル基または炭素数１〜２０のアルキニル基を示す。Ｒ^１およびＲ^２は、同一であっても異なっていてもよい。Ｍ^＋はナトリウムイオン、カリウムイオンまたはリチウムイオンを示す。） The first method for manufacturing a tire member in the present disclosure includes a step of making a masterbatch and a step of mixing the masterbatch and an organic acid metal salt. The step of making a masterbatch includes a step of coagulating the pre-coagulation rubber latex containing carbon black to obtain a coagulated product. The step of making a masterbatch further includes a step of adding a compound of the following formula (I) (hereinafter, referred to as “formula (I) compound”) to a coagulated product containing water. The step of making a masterbatch further comprises the step of dispersing the compound of formula (I) in the coagulated product.

In (formula (I), ^{R 1} and ^{R 2} are hydrogen atom, an alkyl group having 1 to 20 carbon atoms, .R ¹ an alkenyl group or an alkynyl group having 1 to 20 carbon atoms having 1 to 20 carbon atoms and R ² may be the same or different. M ⁺ indicates sodium ion, potassium ion or lithium ion.)

The second method for manufacturing a tire member in the present disclosure includes a step of making a masterbatch and a step of mixing the masterbatch and an organic acid metal salt. The step of making a master batch includes a step of adding the compound of formula (I) to the mixture containing carbon black and rubber, and a step of dispersing the compound of formula (I) in the mixture in the presence of water.

Organic acid metal salts such as cobalt stearate may be added to the rubber to improve the adhesion between the steel cord and the rubber.

However, organic acid metal salts reduce deterioration resistance. It is considered that this is because the organic acid metal salt promotes radical generation.

The present disclosure provides a method capable of manufacturing a tire member that is resistant to deterioration. Further, the present disclosure provides a method capable of producing a tire resistant to deterioration.

The first method for manufacturing a tire member includes a step of making a masterbatch and a step of mixing the masterbatch and an organic acid metal salt. The step of making a masterbatch includes a step of coagulating the pre-coagulation rubber latex containing carbon black to obtain a coagulated product. The step of making a masterbatch further includes the step of adding the compound of formula (I) to the coagulated product containing water. The step of making a masterbatch further comprises the step of dispersing the compound of formula (I) in the coagulated product.

The first method for manufacturing a tire member can manufacture a tire member that is more resistant to thermal deterioration and bending deterioration than the preceding manufacturing method. First, the first method for manufacturing a tire member can highly disperse the compound of formula (I) having a function of capturing radicals generated by breaking a polymer chain due to heat and bending. Secondly, in the first method for manufacturing a tire member, carbon black can be highly dispersed and the occurrence of crack origin can be suppressed.

The first method of manufacturing a tire member is capable of highly dispersing the compound of formula (I). Since the compound of formula (I) exhibits hydrophilicity and the rubber exhibits hydrophobicity in a dry state, it is difficult for the compound of formula (I) to disperse in the prior production method. On the other hand, in the first method of manufacturing a tire member, the water content of the coagulated product can help disperse the compound of formula (I). Therefore, the first tire member manufacturing method can improve the dispersibility of the compound of formula (I) as compared with the prior manufacturing method.

The first method of manufacturing a tire member can highly disperse carbon black. This is because the first method for manufacturing a tire member is to coagulate a pre-coagulation rubber latex containing carbon black and disperse the compound of formula (I) in the coagulated product in the presence of water.

In the first method for manufacturing a tire member, the step of making a master batch is to solidify the pre-coagulation rubber latex containing carbon black, and before the step of obtaining a coagulated product, the carbon black and the first rubber latex are mixed. The step of obtaining the carbon black slurry and the step of mixing the carbon black slurry and the second rubber latex to obtain the rubber latex before the solidification treatment can be further included.

In the first method for manufacturing a tire member, the step of dispersing the compound of formula (I) in the coagulated product is preferably a step of dispersing the compound of formula (I) in the coagulated product while dehydrating the coagulated product.

In the step of adding the compound of formula (I) to the coagulated product in the first method for manufacturing a tire member, the water content of the coagulated product is Wa with respect to 100 parts by mass of the rubber in the coagulated product, and 100 mass of rubber in the coagulated product is used. When the amount of the compound of the formula (I) added to the portion is Wb, the ratio of Wa to Wb (Wa / Wb) is preferably 1 to 8100.

The method for manufacturing the first tire member can be included in the method for manufacturing the first tire.

The second method for manufacturing a tire member includes a step of making a masterbatch and a step of mixing the masterbatch and an organic acid metal salt. The step of making a master batch includes a step of adding the compound of formula (I) to the mixture containing carbon black and rubber, and a step of dispersing the compound of formula (I) in the mixture in the presence of water.

The second tire member manufacturing method can manufacture a tire member that is more resistant to thermal deterioration and bending deterioration than the preceding manufacturing method. This is because the second method for manufacturing a tire member can highly disperse the compound of formula (I) having a radical scavenging ability.

The method for manufacturing the second tire member can be included in the method for manufacturing the second tire.

The method for manufacturing a tire member according to the first embodiment includes a step of mixing carbon black and rubber latex to obtain a carbon black slurry. By mixing carbon black and rubber latex, reaggregation of carbon black can be prevented. This is because it is considered that an extremely thin latex phase is formed on a part or all of the surface of the carbon black, and the latex phase suppresses the reaggregation of the carbon black. As the carbon black, for example, carbon black used in the ordinary rubber industry such as SAF, ISAF, HAF, FEF, and GPF, as well as conductive carbon black such as acetylene black and Ketjen black can be used. The carbon black may be a granulated carbon black or an ungranulated carbon black that has been granulated in consideration of its handleability in the ordinary rubber industry. The rubber latex in the process of producing the carbon black slurry is, for example, natural rubber latex or synthetic rubber latex. The number average molecular weight of natural rubber in natural rubber latex is, for example, 2 million or more. Synthetic rubber latex is, for example, styrene-butadiene rubber latex, butadiene rubber latex, nitrile rubber latex, chloroprene rubber latex. The solid content (rubber) concentration of the rubber latex is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, and further preferably 0.3% by mass or more. The upper limit of the solid content concentration is, for example, 5% by mass, preferably 2% by mass, and more preferably 1% by mass. Carbon black and rubber latex can be mixed with a general disperser such as a high shear mixer, a high shear mixer, a homomixer, a ball mill, a bead mill, a high pressure homogenizer, an ultrasonic homogenizer, and a colloid mill.

In the carbon black slurry, carbon black is dispersed in water. The amount of carbon black in the carbon black slurry is preferably 1% by mass or more, more preferably 3% by mass or more, based on 100% by mass of the carbon black slurry. The upper limit of the amount of carbon black in the carbon black slurry is preferably 15% by mass, more preferably 10% by mass.

The method for manufacturing a tire member according to the first embodiment further includes a step of mixing a carbon black slurry and a rubber latex to obtain a rubber latex before solidification treatment. The rubber latex to be mixed with the carbon black slurry is, for example, natural rubber latex, synthetic rubber latex, or the like. The solid content concentration of the rubber latex to be mixed with the carbon black slurry is preferably higher than the solid content concentration of the rubber latex in the step of producing the carbon black slurry. The solid content concentration of the rubber latex to be mixed with the carbon black slurry is preferably 10% by mass or more, more preferably 20% by mass or more. The upper limit of the solid content concentration in the rubber latex is, for example, 60% by mass, preferably 40% by mass, and more preferably 30% by mass. The carbon black slurry and rubber latex can be mixed by a general disperser such as a high shear mixer, a high shear mixer, a homomixer, a ball mill, a bead mill, a high-pressure homogenizer, an ultrasonic homogenizer, and a colloid mill.

In the rubber latex before solidification treatment, rubber particles, carbon black, etc. are dispersed in water.

The method for manufacturing a tire member according to the first embodiment further includes a step of coagulating the rubber latex before the coagulation treatment to obtain a coagulated product. A coagulant can be added to the pre-coagulation rubber latex to cause coagulation. The coagulant is, for example, an acid. Examples of the acid include formic acid and sulfuric acid. The coagulated product obtained by coagulating the rubber latex before the coagulation treatment contains water.

The method for manufacturing a tire member according to the first embodiment further includes a step of adding the compound of formula (I) to the coagulated product. In the step of adding the compound of formula (I), the water content Wa of the coagulated product is, for example, 1 part by mass or more, preferably 10 parts by mass or more, based on 100 parts by mass of the rubber in the coagulated product. The upper limit of Wa is, for example, 800 parts by mass, preferably 600 parts by mass. The addition amount Wb of the compound of the formula (I) is, for example, 0.1 part by mass or more, preferably 0.5 part by mass or more, based on 100 parts by mass of the rubber in the coagulated product. The upper limit of Wb is, for example, 10 parts by mass, preferably 5 parts by mass. The ratio of Wa to Wb (Wa / Wb) is preferably 1 to 8100. If Wa / Wb is less than 1, the effect of improving heat aging resistance and fatigue resistance will not be large. Above 8100, water in the coagulum may remain in the masterbatch.

（式（Ｉ）において、Ｒ^１およびＲ^２は、水素原子、炭素数１〜２０のアルキル基、炭素数１〜２０のアルケニル基または炭素数１〜２０のアルキニル基を示す。Ｒ^１およびＲ^２は、同一であっても異なっていてもよい。Ｍ^＋はナトリウムイオン、カリウムイオンまたはリチウムイオンを示す。）
式（Ｉ）において、Ｒ^１およびＲ^２が水素原子であることが好ましい。Ｍ^＋がナトリウムイオンであることが好ましい。式（Ｉ）化合物は、好ましくは下記式（Ｉ’）の化合物である。

The formula (I) is shown below.

In (formula (I), ^{R 1} and ^{R 2} are hydrogen atom, an alkyl group having 1 to 20 carbon atoms, .R ¹ an alkenyl group or an alkynyl group having 1 to 20 carbon atoms having 1 to 20 carbon atoms and R ² may be the same or different. M ⁺ indicates sodium ion, potassium ion or lithium ion.)
In formula (I), it is preferable that R ¹ and R ² are hydrogen atoms. It is preferable that M ⁺ is a sodium ion. The compound of formula (I) is preferably a compound of the following formula (I').

The method for manufacturing a tire member according to the first embodiment further includes a step of dispersing the compound of formula (I) in a coagulated product. The step of dispersing the compound of formula (I) in the coagulated product is, for example, a step of dispersing the compound of formula (I) in the coagulated product while dehydrating the coagulated product after the addition of the compound of formula (I). Specifically, it is a step of dispersing the compound of formula (I) in the coagulated product while applying a shearing force at 100 ° C. to 250 ° C. to the coagulated product after the addition of the compound of formula (I). The lower limit of the temperature is preferably 120 ° C. The upper limit of the temperature is preferably 230 ° C. An extruder such as a single-screw extruder can be used to disperse the compound of formula (I) in the coagulated product.

The method for manufacturing a tire member according to the first embodiment further includes a step of obtaining a masterbatch by drying and plasticizing the coagulated product after dispersing the compound of the formula (I).

The masterbatch contains rubber. The rubber is, for example, natural rubber, isoprene rubber, butadiene rubber, styrene-butadiene rubber, nitrile rubber, chloroprene rubber and the like. The amount of natural rubber in the masterbatch is preferably 70% by mass or more, more preferably 80% by mass or more, still more preferably 90% by mass or more, still more preferably 100% by mass, based on 100% by mass of rubber.

The masterbatch further contains carbon black. The amount of carbon black is preferably 10 parts by mass or more, more preferably 20 parts by mass or more, and further preferably 30 parts by mass or more with respect to 100 parts by mass of rubber. The amount of carbon black is preferably 80 parts by mass or less, more preferably 60 parts by mass or less, based on 100 parts by mass of rubber.

The masterbatch further comprises the compound of formula (I). The amount of the compound of the formula (I) is preferably 0.1 part by mass or more, more preferably 0.5 part by mass or more, and further preferably 1 part by mass or more with respect to 100 parts by mass of the rubber. The amount of the compound of formula (I) is preferably 10 parts by mass or less, more preferably 8 parts by mass or less, based on 100 parts by mass of rubber.

The method for manufacturing a tire member according to the first embodiment further includes a step of dry-mixing a masterbatch and a compounding agent such as an organic acid metal salt with a mixer to obtain a mixture. Organic acid metal salts, e.g., cobalt naphthenate, cobalt stearate, cobalt oleate, cobalt neodecanoate, cobalt rosin acid, maleic acid cobalt of any organic acid cobalt salt, organic acid nickel salts, organic acid molybdenum salts and the like Can be mentioned. Among them, cobalt naphthenate, preferably stearic acid cobalt, cobalt stearate is preferable. These can be used alone or in admixture of two or more. The amount of the organic acid metal salt added is, for example, 0.03 parts by mass or more, preferably 0.05 parts by mass or more, more preferably 0.1 parts by mass, in terms of metal content, with respect to 100 parts by mass of the rubber derived from the master batch. That is all. The upper limit of the amount of the organic acid metal salt added is, for example, 1 part by mass, preferably 0.7 parts by mass, and more preferably 0.4 parts by mass with respect to 100 parts by mass of the rubber derived from the masterbatch. Examples of the mixer include a closed mixer and an open roll. Banbury mixers, kneaders, etc. can be mentioned as closed mixers.

Other formulations include, for example, methylene receptors, methylene donors, oils, zinc oxide, stearic acid, anti-aging agents and the like. Examples of the methylene receptor include phenolic compounds and phenolic resins obtained by condensing phenolic compounds with formaldehyde. Examples of the phenolic compound include phenol, resorcin, and alkyl derivatives thereof. Examples of the alkyl derivative include methyl group derivatives such as cresol and xylenol, as well as derivatives using relatively long-chain alkyl groups such as nonylphenol and octylphenol. The phenolic compound may contain an acyl group such as an acetyl group as a substituent. Examples of the phenol-based resin include resorcin-formaldehyde resin, phenol resin (that is, phenol-formaldehyde resin), cresol resin (that is, cresol-formaldehyde resin), and formaldehyde resin composed of a plurality of phenolic compounds. These are uncured resins, preferably liquid or thermally fluid. Among them, the methylene receptor is preferably a resorcin or a resorcin derivative, and more preferably a resorcin or a resorcin-alkylphenol cocondensed formalin resin from the viewpoint of compatibility with a rubber component and the like, the denseness of the resin after curing, and reliability. is there. The amount of the methylene receptor added is, for example, 1 part by mass or more with respect to 100 parts by mass of the rubber derived from the masterbatch. The upper limit of the amount of the methylene receptor added is, for example, 10 parts by mass, preferably 4 parts by mass, based on 100 parts by mass of the rubber derived from the masterbatch. Examples of the methylene donor include hexamethylenetetramine and melamine derivatives. Examples of the melamine derivative include methylol melamine, a partially etherified product of methylol melamine, and a condensate of melamine, formaldehyde, and methanol. Of these, hexamethoxymethylmelamine is preferable. The amount of the methylene donor added is, for example, 0.2 parts by mass or more, preferably 1 part by mass or more, based on 100 parts by mass of the rubber derived from the masterbatch. The upper limit of the amount of the methylene donor added is, for example, 20 parts by mass, preferably 8 parts by mass, based on 100 parts by mass of the rubber derived from the masterbatch. As anti-aging agents, aromatic amine anti-aging agents, amine-ketone anti-aging agents, monophenol anti-aging agents, bisphenol anti-aging agents, polyphenol anti-aging agents, dithiocarbamate anti-aging agents, thiourea anti-aging agents Anti-aging agents and the like can be mentioned.

The method for producing a tire member according to the first embodiment further includes a step of adding a vulcanization-based compounding agent to the mixture and kneading the vulcanization-based compounding agent into the mixture to obtain a rubber composition. Examples of the vulcanization-based compounding agent include vulcanization agents such as sulfur and organic peroxides, vulcanization accelerators, vulcanization acceleration aids, and vulcanization retarders. Examples of sulfur include powdered sulfur, precipitated sulfur, insoluble sulfur, and highly dispersible sulfur. Sulfenamide-based vulcanization accelerator, thiuram-based vulcanization accelerator, thiazole-based vulcanization accelerator, thiourea-based vulcanization accelerator, guanidine-based vulcanization accelerator, dithiocarbamate-based vulcanization accelerator as vulcanization accelerators And so on.

The rubber composition contains a rubber component containing natural rubber. The amount of natural rubber is preferably 40% by mass or more, more preferably 50% by mass or more, based on 100% by mass of the rubber component. The upper limit of the amount of natural rubber is, for example, 100% by mass.

The rubber composition further comprises carbon black. The amount of carbon black is preferably 10 parts by mass or more, more preferably 20 parts by mass or more, and further preferably 30 parts by mass or more with respect to 100 parts by mass of the rubber component. The amount of carbon black is preferably 80 parts by mass or less, and more preferably 60 parts by mass or less with respect to 100 parts by mass of the rubber component.

The rubber composition further comprises a compound of formula (I). The amount of the compound of the formula (I) is preferably 0.1 part by mass or more, and more preferably 0.5 part by mass or more with respect to 100 parts by mass of the rubber component. The amount of the compound of the formula (I) is preferably 10 parts by mass or less, more preferably 8 parts by mass or less, based on 100 parts by mass of the rubber component.

The rubber composition further comprises an organic acid metal salt. The amount of the organic acid metal salt is, for example, 0.03 parts by mass or more, preferably 0.05 parts by mass or more, and more preferably 0.1 parts by mass or more in terms of metal content with respect to 100 parts by mass of the rubber component. The upper limit of the amount of the organic acid metal salt is, for example, 1 part by mass, preferably 0.7 parts by mass, and more preferably 0.4 parts by mass with respect to 100 parts by mass of the rubber component.

The rubber composition further comprises a methylene receptor. The amount of the methylene receptor is, for example, 1 part by mass or more with respect to 100 parts by mass of the rubber component. The upper limit of the amount of the methylene receptor is, for example, 10 parts by mass, preferably 4 parts by mass with respect to 100 parts by mass of the rubber component.

The rubber composition further comprises a methylene donor. For example, it is 0.2 parts by mass or more, preferably 1 part by mass or more with respect to 100 parts by mass of the rubber component. The upper limit of the amount of the methylene donor added is, for example, 20 parts by mass, preferably 8 parts by mass with respect to 100 parts by mass of the rubber component.

The rubber composition can further include oils, zinc oxide, stearic acid, anti-aging agents, sulfur, vulcanization accelerators and the like. The amount of sulfur is, for example, 1 part by mass or more, preferably 2 parts by mass or more in terms of sulfur content, with respect to 100 parts by mass of the rubber component. The upper limit of the amount of sulfur is, for example, 10 parts by mass, preferably 8 parts by mass in terms of sulfur content, with respect to 100 parts by mass of the rubber component. The amount of the vulcanization accelerator is preferably 0.1 part by mass to 5 parts by mass with respect to 100 parts by mass of the rubber component.

The method for manufacturing a tire according to the first embodiment includes a step of covering a steel cord with a rubber composition to obtain a tire member such as a steel belt or a steel breaker. The surface of the steel cord is generally brass plated.

The method for manufacturing a tire according to the first embodiment includes a step of manufacturing a raw tire including a steel belt, a steel breaker, and the like. The method for manufacturing a tire according to the first embodiment further includes a step of heating the raw tire. The tire obtained by the method of the first embodiment can be a pneumatic tire. The tire obtained by the method of the first embodiment can be a heavy load tire.

A modified example of the first embodiment will be described here. Although the method for manufacturing a tire member in the first embodiment includes a step of mixing carbon black and rubber latex to obtain a carbon black slurry, a modified example of the first embodiment uses carbon black and water instead of this step. Is mixed to obtain a carbon black slurry.

The method for producing a tire member according to the second embodiment includes a step of adding a compound of formula (I) to a mixture containing carbon black and rubber. The amount of carbon black in the mixture is preferably 10 parts by mass or more, more preferably 20 parts by mass or more, and further preferably 30 parts by mass or more with respect to 100 parts by mass of rubber. The amount of carbon black is preferably 80 parts by mass or less, more preferably 60 parts by mass or less, based on 100 parts by mass of rubber. The rubber is, for example, natural rubber, isoprene rubber, butadiene rubber, styrene-butadiene rubber, nitrile rubber, chloroprene rubber and the like. The amount of natural rubber in the mixture is preferably 70% by mass or more, more preferably 80% by mass or more, still more preferably 90% by mass or more, still more preferably 100% by mass, based on 100% by mass of rubber. The amount of the compound of formula (I) added is, for example, 0.1 to 10 parts by mass with respect to 100 parts by mass of rubber in the mixture.

The method for producing a tire member according to the second embodiment further includes a step of dispersing the compound of formula (I) in the mixture in the presence of water to obtain a masterbatch. The water content of the mixture is, for example, 1 part by mass or more, preferably 10 parts by mass or more, based on 100 parts by mass of the rubber in the mixture. The upper limit of the water content of the mixture is, for example, 800 parts by mass, preferably 600 parts by mass. For the masterbatch, the description of the first embodiment is incorporated.

The method for manufacturing a tire member according to the second embodiment further includes a step of dry-mixing a masterbatch and a compounding agent such as an organic acid metal salt with a mixer to obtain a mixture before adding a vulcanization-based compounding agent. For this, the description of the first embodiment is incorporated.

The step of adding a vulcanization compound to the pre-addition mixture of the vulcanization compound and kneading the vulcanization compound into the pre-addition mixture of the vulcanization compound to obtain a rubber composition is a step of obtaining a rubber composition. The manufacturing method of is further included. For this, the description of the first embodiment is incorporated.

The method for manufacturing a tire according to the second embodiment includes a step of covering a steel cord with a rubber composition to obtain a tire member such as a steel belt or a steel breaker.

The method for manufacturing a tire according to the second embodiment includes a step of manufacturing a raw tire provided with a steel belt, a steel breaker, and the like. The method for manufacturing a tire according to the second embodiment further includes a step of heating the raw tire. The tire obtained by the method of the second embodiment can be a pneumatic tire. The tire obtained by the method of the second embodiment can be a heavy load tire.

Examples of the present disclosure will be described below.

The raw materials and chemicals are shown below.
Natural rubber latex (Dry Rubber Content = 31.2%) Golden Hope coagulant Formic acid (1st grade 85%) Nacalai Tesque (10% solution diluted, adjusted to pH 1.2 and used)
Carbon Black "Seast 300" manufactured by Tokai Carbon Co., Ltd. Compound 1 (2Z) -4-[(4-aminophenyl) amino] -4-oxo-2-sodium butenoate (compound of formula (I')) manufactured by Sumitomo Chemical Co., Ltd. Natural rubber RSS # 3
Zinc oxide "Zinc oxide No. 3" Stearic acid manufactured by Mitsui Kinzoku Co., Ltd. "Bead stearic acid" Anti-aging agent manufactured by Nippon Yushi Co., Ltd. "Nocrack 6C" Resolsin-alkylphenol-formalin resin manufactured by Ouchi Shinko Kagaku Co. Hexamethoxymethylmelamine "Silet's 963L" Mitsui Cytec Co., Ltd. Cobalt stearate "Cobalt stearate (Co content 9.5%)" Japan Energy Co., Ltd. "DICNAME NBC-2 (Co content 22.5%)" Dainippon Ink Insoluble sulfur "Muclon HS OT-20" manufactured by Kagaku Kogyo Co., Ltd. Vulcanization accelerator "Noxeller DZ-G" (N, N-dicyclohexyl-2-benzothiazolyl sulfene amide) manufactured by Flexis Co., Ltd.

Preparation of Wet Master Batch in Examples 1 and 2 Water was added to concentrated natural rubber latex at 25 ° C. to dilute natural rubber latex with a solid content (rubber) concentration of 0.52% by mass and a solid content (rubber) concentration of 28% by mass. Obtained with natural rubber latex. 50 parts by mass of carbon black was added to 954.8 parts by mass of the dilute natural rubber latex, and the diluted natural rubber latex after the addition of carbon black was stirred with Robomix manufactured by PRIMIX Corporation to obtain a carbon black / natural rubber slurry. Add carbon black / natural rubber slurry to natural rubber latex with a solid content (rubber) concentration of 28% by mass according to Table 1, and add carbon black / natural rubber slurry to the natural rubber latex with a household mixer manufactured by SANYO at 11300 rpm. , Stirred for 30 minutes to obtain a rubber latex before solidification treatment. Formic acid as a coagulant was added to the rubber latex before the coagulation treatment until the pH reached 4, and the coagulated product and the waste liquid were separated by a filter. Compound 1 is added to the coagulated product, and the coagulated product after the addition of compound 1 is dehydrated and plasticized at 180 ° C. using a screw press V-02 (squeezer type uniaxial extrusion dehydrator) manufactured by Suehiro EPM, and then into the coagulated product. Compound 1 was dispersed. A wet masterbatch was obtained by the above procedure.

Preparation of Wet Master Batches in Comparative Examples 1 and 2 Wet master batches of Comparative Examples 1 and 2 were obtained by the same procedure as in Example 1 except that compound 1 was not added to the coagulated product.

Preparation of Wet Masterbatch in Comparative Example 3 A wet masterbatch of Comparative Example 3 was prepared by the same procedure as in Example 1 except that the coagulated product was substantially completely dehydrated before adding Compound 1 to the coagulated product. did.

Preparation of unvulcanized rubber in each example A compounding agent excluding sulfur and a vulcanization accelerator was added according to Table 1, kneaded with a B-type Banbury mixer manufactured by Kobe Steel, and the rubber mixture was discharged. The rubber mixture, sulfur and the vulcanization accelerator were kneaded with a B-type Banbury mixer to obtain unvulcanized rubber.

The heat-resistant aging unvulcanized rubber was vulcanized at 150 ° C. for 30 minutes. The tensile strength of the vulcanized rubber was measured according to JIS K 6251: 2010, and the tensile strength was measured again after the heat aging treatment of exposing the vulcanized rubber to 90 ° C. for 96 hours. The degree of change in tensile strength due to heat aging treatment is shown as an index with the value of Comparative Example 1 as 100. The larger the index, the smaller the change in tensile strength and the better the heat aging resistance.

Fatigue resistant unvulcanized rubber was vulcanized at 150 ° C. for 30 minutes. The bending crack growth test of the vulcanized rubber was carried out at 23 ° C. in accordance with JIS K 6260: 2010. The number of bends until the crack length reached 2 mm was determined, and the number of bends was indicated by an index with the value of Comparative Example 1 as 100. The larger the index, the greater the number of bendings and the better the bending fatigue resistance.

The addition of Compound 1 in the water-containing coagulated product brought about improvements in heat aging resistance and fatigue resistance. For example, the addition of 2 parts by mass of Compound 1 in a water-containing coagulated product resulted in a 20 point improvement in heat aging resistance and a 10 point improvement in fatigue resistance. (See Comparative Example 1 and Example 1). On the other hand, the addition of Compound 1 in the Banbury mixer kneading resulted in only 4 points of improvement in heat aging resistance and only 2 points of improvement in fatigue resistance. (See Comparative Example 1 and Comparative Example 2). The addition of Compound 1 after complete dehydration resulted in 2 points of deterioration in heat aging resistance and 5 points of deterioration in fatigue resistance. (See Comparative Example 1 and Comparative Example 3).

Claims (5)

The process of making a masterbatch and
Including the step of mixing the masterbatch and the organic acid metal salt.
The process of making the masterbatch is
The process of coagulating the pre-coagulation rubber latex containing carbon black to obtain a coagulated product,
The step of adding the compound of the following formula (I) to the coagulated product containing water, and
A step of dispersing the compound in the coagulated product.
Manufacturing method of tire parts.

In (formula (I), ^{R 1} and ^{R 2} are hydrogen atom, an alkyl group having 1 to 20 carbon atoms, .R ¹ an alkenyl group or an alkynyl group having 1 to 20 carbon atoms having 1 to 20 carbon atoms and R ² may be the same or different. M ⁺ indicates sodium ion, potassium ion or lithium ion.) The method for producing a tire member according to claim 1, wherein the step of dispersing the compound in the coagulated product is a step of dispersing the compound in the coagulated product while dehydrating the coagulated product. A method for manufacturing a tire, which comprises the method for manufacturing a tire member according to claim 1 or 2. The process of making a masterbatch and
Including the step of mixing the masterbatch and the organic acid metal salt.
The process of making the masterbatch is
The step of adding the compound of the following formula (I) to the mixture containing carbon black and rubber, and
Including the step of dispersing the compound in the mixture in the presence of water.
Manufacturing method of tire parts.

In (formula (I), ^{R 1} and ^{R 2} are hydrogen atom, an alkyl group having 1 to 20 carbon atoms, .R ¹ an alkenyl group or an alkynyl group having 1 to 20 carbon atoms having 1 to 20 carbon atoms and R ² may be the same or different. M ⁺ indicates sodium ion, potassium ion or lithium ion.) A method for manufacturing a tire, which comprises the method for manufacturing a tire member according to claim 4.