JP6912357B2 - Masterbatch manufacturing method, tire rubber composition manufacturing method and tire manufacturing method - Google Patents

Description

The present disclosure relates to a method for producing a masterbatch, a method for producing a rubber composition for a tire, and a method for producing a tire.

In Patent Documents 1 and 2, a compound called (2Z) -4-[(4-aminophenyl) amino] -4-oxo-2-sodium butenoate is added to rubber and kneaded with a Banbury mixer, that is, It discloses that this compound is dispersed in rubber by dry kneading.

Japanese Unexamined Patent Publication No. 2014-95019 Japanese Unexamined Patent Publication No. 2014-95020

However, since this compound easily aggregates to form an agglomerate, it is difficult to highly disperse this compound in rubber by dry kneading.

On the other hand, the tensile strength of the vulcanized rubber can be improved by enhancing the dispersion of this compound and fully exerting the coupling function of this compound, that is, the function of connecting the rubber polymer and carbon black.

An object of the present disclosure is to provide a method for producing a masterbatch capable of improving the tensile strength of vulcanized rubber at the time of cutting. Another object of the present disclosure is to provide a method for producing a rubber composition capable of improving the tensile strength of the vulcanized rubber at the time of cutting. Another object of the present disclosure is to provide a method of manufacturing a tire.

（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 method for producing a master batch in the present disclosure includes a step of adding a compound of the following formula (I) to a rubber latex to obtain a rubber latex after the addition, and a step of mixing the rubber latex after the addition and a carbon black slurry.

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 rubber composition for a tire in the present disclosure includes the method for producing the masterbatch. That is, the method for producing a rubber composition for a tire in the present disclosure is a step of adding a compound of formula (I) to a rubber latex to obtain a rubber latex after the addition, and a step of mixing the rubber latex after the addition and a carbon black slurry. And include.

The method for producing a tire in the present disclosure includes the method for producing the master batch, that is, the method for producing a tire in the present disclosure includes a step of adding a compound of formula (I) to a rubber latex to obtain a rubber latex after the addition. The step of mixing the rubber latex and the carbon black slurry after the addition is included.

（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 method for producing the master batch of the embodiment in the present disclosure includes a step of adding the compound of the following formula (I) to the rubber latex to obtain the rubber latex after the addition, and a step of mixing the rubber latex after the addition and the carbon black slurry. including.

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 masterbatch manufacturing method of the embodiment in the present disclosure can improve the tensile strength of the vulcanized rubber at the time of cutting. Since the compound of the formula (I) can be dissolved in the rubber latex, the aggregation of the compound of the formula (I) is suppressed in the rubber latex after the addition. On the other hand, in the carbon black slurry, carbon black is dispersed. By mixing the carbon black slurry and the rubber latex after addition, it is possible to efficiently react the carbon black with the compound of the formula (I), and the rubber and the carbon black can be firmly connected. Therefore, the method for producing the masterbatch of the embodiment in the present disclosure can improve the tensile strength of the vulcanized rubber at the time of cutting.

Embodiment 1
Hereinafter, the first embodiment of the present disclosure will be described.

The method for producing a tire in the first embodiment is a step of adding a compound of formula (I) to a rubber latex to obtain a rubber latex after the addition, and mixing the rubber latex after the addition and a carbon black slurry to obtain a rubber latex before coagulation treatment. The step of obtaining, the step of coagulating the rubber latex before coagulation treatment to obtain a master batch, the step of kneading at least the master batch and the compounding agent to obtain a mixture, and the step of kneading the vulcanization-based compounding agent into the mixture to form a rubber composition. It includes a step of obtaining a product and a step of vulcanizing and molding an unvulcanized tire made of a rubber composition.

The method for manufacturing a tire according to the first embodiment includes a step of adding a compound of the formula (I) to a rubber latex to obtain a rubber latex after the addition. Rubber latex contains rubber particles and water. In rubber latex, rubber particles are colloidally dispersed in water. The rubber latex can contain ammonia. The rubber latex is, for example, a natural rubber latex, a synthetic rubber latex, or the like. 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 dry rubber content of the rubber latex can be, for example, 10% by mass or more, and can be 20% by mass or more. The upper limit of the dry rubber content in the rubber latex is, for example, 60% by mass, 50% by mass, and the like. The amount of the compound of the formula (I) is preferably 0.05 parts by mass or more, more preferably 0.1 parts by mass or more, still more preferably 1 part by mass or more, based on 100 parts by mass of the dried rubber content of the rubber latex. More preferably, it is 2 parts by mass or more. The amount of the compound of the formula (I) is, for example, 10 parts by mass or less with respect to 100 parts by mass of the dried rubber content of the rubber latex.

（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）の化合物は、カップリング機能、すなわちゴムポリマーとカーボンブラックとをつなぐ機能を有する。具体的には、末端の窒素官能基がカーボンブラックと結合することが可能であり、炭素−炭素二重結合の部分がゴムポリマーと結合できると考えられる。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.)
The compound of formula (I) has a coupling function, that is, a function of connecting the rubber polymer and carbon black. Specifically, it is considered that the terminal nitrogen functional group can be bonded to carbon black, and the carbon-carbon double bond portion can be bonded to the rubber polymer. 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 according to the first embodiment includes a step of mixing a rubber latex after addition and a carbon black slurry to obtain a rubber latex before solidification treatment. The carbon black slurry contains carbon black and water. In the carbon black slurry, carbon black is dispersed in water. The carbon black slurry can be obtained by adding carbon black to water and stirring the mixture. As the carbon black, for example, SAF, ISAF, HAF, FEF, GPF and the like, 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. 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. After addition, the rubber latex and the carbon black slurry can be mixed with a general disperser such as a high shear mixer, a homomixer, a ball mill, a bead mill, a high-pressure homogenizer, an ultrasonic homogenizer, or a colloid mill.

The method for manufacturing a tire according to the first embodiment includes a step of coagulating the rubber latex before the coagulation treatment to obtain a masterbatch. 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. Before the coagulation treatment The coagulated product obtained by coagulating the rubber latex contains water. This step can include dehydrating the coagulated product and plasticizing it while drying. In this step, the coagulated product can be dehydrated by pressing and evaporation using an extruder, and then plasticized while being dried after dehydration. Examples of the extruder include a uniaxial extruder. A masterbatch can be obtained by such a procedure.

The masterbatch comprises rubber, carbon black, and a compound of formula (I). 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 amount of carbon black in the masterbatch 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 in the masterbatch 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 amount of the compound of the formula (I) in the masterbatch can be 0.05 parts by mass or more with respect to 100 parts by mass of the rubber. The amount of the compound of the formula (I) in the masterbatch can be 10 parts by mass or less with respect to 100 parts by mass of the rubber.

The method for producing a tire according to the first embodiment includes at least a step of kneading a masterbatch and a compounding agent to obtain a mixture. Examples of the compounding agent include carbon black, zinc oxide, stearic acid, and an antiaging agent. One or more of these can be selected and kneaded with the masterbatch. When carbon black is added at the time of kneading, as the carbon black, for example, SAF, ISAF, HAF, FEF, GPF and the like, 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. The grade of carbon black added at the time of kneading is ASTM (American Society for Testing and Materials), which may be the same as or different from the grade of carbon black in the masterbatch. By adding carbon black during kneading, it is possible to suppress the adhesion of the compounding agent to the kneading machine (for example, in the case of a Banbury mixer, the adhering of the compounding agent to the chamber wall), and the compounding agent using rubber. Can be improved. 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. In this kneading step, other rubbers can be kneaded together with the masterbatch and the compounding agent. Examples of the rubber added to the master batch at the time of kneading include natural rubber, polyisoprene rubber, styrene-butadiene rubber, nitrile rubber, and chloroprene rubber. Kneading can be performed in a closed mixer. Banbury mixers, kneaders, etc. can be mentioned as closed mixers.

The method for producing a tire according to the first embodiment further includes a step of kneading a 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 comprises rubber derived from the masterbatch. The amount of rubber derived from the masterbatch can be, for example, 40% by mass or more, 60% by mass or more, and 80% by mass or more with respect to 100% by mass of rubber in the rubber composition. It can be, and it can be 100% by mass.

The rubber composition comprises a compound of formula (I). The amount of the compound of the formula (I) is preferably 0.05 parts by mass or more, more preferably 0.1 parts by mass or more, still more preferably 1 part by mass or more, based on 100 parts by mass of the rubber in the rubber composition. More preferably, it is 2 parts by mass or more. The amount of the compound of the formula (I) is, for example, 10 parts by mass or less with respect to 100 parts by mass of the rubber in the rubber composition.

The rubber composition 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 in the rubber composition. 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 in the rubber composition.

The rubber composition can further contain stearic acid, zinc oxide, anti-aging agents, sulfur, vulcanization accelerators and the like. The amount of sulfur is preferably 0.5 parts by mass to 5 parts by mass in terms of sulfur content with respect to 100 parts by mass of rubber in the rubber composition. 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 rubber in the rubber composition.

The rubber composition can be used in the production of tires. Specifically, it can be used for manufacturing a tire member constituting a tire, and for example, it can be used for manufacturing sidewall rubber, tread rubber, and the like.

The method for manufacturing a tire according to the first embodiment includes a step of vulcanizing and molding an unvulcanized tire made of a rubber composition. The unvulcanized tire comprises a tire member made of a rubber composition.

Modification 1
In order to obtain a carbon black slurry, in the method for producing a tire in the first embodiment, carbon black is added to water and stirred, but in the first modification, carbon black is added to a dilute rubber latex and stirred. The dilute rubber latex can be obtained, for example, by adding water to the rubber latex. The rubber latex used for producing the dilute rubber latex is, for example, a natural rubber latex or a 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 dry rubber content of the dilute 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 dry rubber content in the rubber latex is, for example, 5% by mass, preferably 2% by mass, and more preferably 1% by mass.

Examples of the present disclosure will be described below.

The raw materials and chemicals are shown below.
Natural rubber latex NR field latex manufactured by Golden Hope (dry rubber content 31.2%)
Natural rubber RSS # 3
Carbon Black "Seast 9 (N110)" manufactured by Tokai Carbon Co., Ltd. Compound 1 "Sumilink 200" manufactured by Sumitomo Chemical Co., Ltd. (2Z) -4-[(4-aminophenyl) amino] -4-oxo-2-sodium butenoate ( Compound of formula (I'))
Zinc Oxide "Zinc Oxide Type 1" Mitsui Kinzoku Co., Ltd. Stearate "Lunac S-20" Kao Co., Ltd. Anti-aging agent "Antigen 6C"(N-phenyl-N'-(1,3-dimethylbutyl) -p-phenylene Diamine) Sumitomo Chemical Co., Ltd. Sulfur "5% oil-containing fine powder sulfur" Tsurumi Chemical Industry Co., Ltd. Vulcanization accelerator "Sunseller NS-G" Sanshin Chemical Industry Co., Ltd.

Preparation of Rubber A To 100 parts by mass of dry rubber, 3 parts by mass of Compound 1 was added to natural rubber latex, poured thinly on a tray, and dried at room temperature to obtain Rubber A.

Preparation of Wet Master Batch A Carbon black was added to water and stirred to prepare a carbon black slurry having 6% by mass of carbon black. The carbon black slurry and the natural rubber latex were mixed so as to be 35 parts by mass of carbon black with respect to 100 parts by mass of the dried rubber content of the natural rubber latex 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, to obtain a coagulated product. The coagulated product was dehydrated with a screw press V-02 (squeezer type uniaxial extrusion dehydrator) manufactured by Suehiro EPM and plasticized while being dried to obtain a wet masterbatch A.

Preparation of Wet Master Batch B To 100 parts by mass of the dried rubber content of the natural rubber latex, 3 parts by mass of Compound 1 was added to the natural rubber latex, and after the addition, a rubber latex was prepared. On the other hand, carbon black was added to water and stirred to prepare a carbon black slurry having 6% by mass of carbon black. The carbon black slurry and the added natural rubber latex were mixed so as to be 35 parts by mass of carbon black with respect to 100 parts by mass of the dried rubber content of the added natural rubber latex 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, to obtain a coagulated product. The coagulated product was dehydrated with a screw press V-02 (squeezer type uniaxial extrusion dehydrator) manufactured by Suehiro EPM and plasticized while being dried to obtain a wet masterbatch B.

Preparation of Rubber B To 100 parts by mass of dry rubber, 0.5 parts by mass of Compound 1 was added to natural rubber latex, poured thinly on a tray, and dried at room temperature to obtain Rubber B.

Preparation of Wet Master Batch C To 100 parts by mass of the dried rubber content of the natural rubber latex, 0.5 parts by mass of Compound 1 was added to the natural rubber latex, and after the addition, a rubber latex was prepared. On the other hand, carbon black was added to water and stirred to prepare a carbon black slurry having 6% by mass of carbon black. The carbon black slurry and the added natural rubber latex were mixed so as to be 35 parts by mass of carbon black with respect to 100 parts by mass of the dried rubber content of the added natural rubber latex 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, to obtain a coagulated product. The coagulated product was dehydrated with a screw press V-02 (squeezer type uniaxial extrusion dehydrator) manufactured by Suehiro EPM and plasticized while being dried to obtain a wet masterbatch C.

Preparation of unvulcanized rubber A compounding agent excluding sulfur and a vulcanization accelerator was added to the rubber according to Table 1, kneaded with a B-type Banbury mixer manufactured by Kobe Steel Co., Ltd., 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.

Tension strength at cutting of vulcanized rubber (TS)
The unvulcanized rubber was vulcanized at 150 ° C. for 30 minutes, a tensile property test was conducted in accordance with JIS K6251: 2010, and the tensile strength at the time of cutting was measured. In Table 1, the value of each example is shown by an index with the value of Comparative Example 1 as 100. The larger the index, the better the tensile strength at the time of cutting.

The cutting tensile strength of the vulcanized rubber in Example 1 was superior to that of Comparative Examples 1 to 3.

Claims (3)

The step of adding the compound of the following formula (I) to the rubber latex and obtaining the rubber latex after the addition,
The step of mixing the rubber latex and the carbon black slurry after the addition is included.
Masterbatch manufacturing method.

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 producing a rubber composition for a tire, which comprises the method for producing a masterbatch according to claim 1. A method for manufacturing a tire, which comprises the method for manufacturing a masterbatch according to claim 1.