JP2019089900A - Method of producing master batch, method of producing rubber composition for tire, and method of manufacturing tire - Google Patents

Abstract

To provide a method of producing a master batch capable of improving tensile strength at break of a vulcanized rubber.SOLUTION: The method of producing a master batch includes the steps of: adding a compound represented by formula (I) to a rubber latex to obtain a rubber latex after addition; and mixing the rubber latex after addition and a carbon black slurry. (Rand Rare each independently H, a C1-20 alkyl group, a C1-20 alkenyl group or a C1-20 alkynyl group; and M is Na, K or Li.)SELECTED DRAWING: None

Description

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

  Patent documents 1 and 2 add a compound called sodium (2Z) -4-[(4-aminophenyl) amino] -4-oxo-2-butenoate to rubber, and knead | mix it with a Banbury mixer, ie, It is disclosed to disperse this compound in rubber by dry milling.

JP, 2014-95019, A JP, 2014-95020, A

  However, since this compound is easily aggregated to form an aggregate, it is difficult to highly disperse the compound in rubber by dry milling.

  On the other hand, the tensile strength of the vulcanized rubber can be improved by enhancing the dispersion of this compound and sufficiently 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 at cutting of a vulcanized rubber. Another object of the present disclosure is to provide a method for producing a rubber composition capable of improving the tensile strength at cutting of a vulcanized rubber. 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 masterbatch in the present disclosure includes the steps of adding a compound of the following formula (I) to a rubber latex, obtaining a rubber latex after addition, and mixing the rubber latex and carbon black slurry after the addition.

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, and M ⁺ represents sodium ion, potassium ion or lithium ion.)

  The method for producing a rubber composition for a tire according to the present disclosure includes the method for producing the master batch. That is, in the method for producing a rubber composition for a tire according to the present disclosure, a compound of the formula (I) is added to a rubber latex, a step of obtaining a rubber latex after addition, and a step of mixing the rubber latex and carbon black slurry after the addition And.

  The method of producing a tire according to the present disclosure includes the method of producing the masterbatch, ie, the method of producing a tire according to the present disclosure adds a compound of formula (I) to a rubber latex and obtains the rubber latex after addition. Mixing the rubber latex and the carbon black slurry after the addition.

（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。） In a method of producing a masterbatch according to an embodiment of the present disclosure, a compound of the following formula (I) is added to a rubber latex, a step of obtaining a rubber latex after addition, a step of mixing a rubber latex and a carbon black slurry after the addition, 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, and M ⁺ represents sodium ion, potassium ion or lithium ion.)

  The method of producing a masterbatch according to an embodiment of the present disclosure can improve the tensile strength at the time of cutting of the vulcanized rubber. Because it is possible to dissolve the compound of formula (I) in the rubber latex, the aggregation of the compound of formula (I) is suppressed in the rubber latex after addition. On the other hand, carbon black is dispersed in the carbon black slurry. By mixing the carbon black slurry and the rubber latex after addition, the carbon black and the compound of the formula (I) can be efficiently reacted, and the rubber and the carbon black can be firmly connected. Therefore, the tensile strength at the time of cutting of the vulcanized rubber can be improved by the method for producing a masterbatch according to the embodiment of the present disclosure.

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

  In the tire manufacturing method according to Embodiment 1, a compound of the formula (I) is added to a rubber latex, and a step of obtaining a rubber latex after addition, and a rubber latex and a carbon black slurry after addition are mixed to obtain a rubber latex before coagulation treatment. Obtaining the rubber latex prior to coagulation treatment to obtain a masterbatch, kneading at least the masterbatch and the compounding agent to obtain a mixture, and kneading the vulcanizing compounding agent into the mixture to obtain a rubber composition And a step of vulcanizing and molding an unvulcanized tire made of the rubber composition.

  The method of manufacturing a tire according to Embodiment 1 includes the steps of adding the compound of formula (I) to the rubber latex and obtaining the rubber latex after the addition. The rubber latex contains rubber particles and water. In the rubber latex, rubber particles are dispersed in water in the form of colloid. 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 the natural rubber in the natural rubber latex is, for example, 2,000,000 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 or 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 dry rubber component 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 based on 100 parts by mass of the dry 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。

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, and M ⁺ represents sodium ion, potassium ion or lithium ion.)
The compounds of formula (I) have a coupling function, ie the function of linking the rubber polymer and carbon black. Specifically, it is believed that the terminal nitrogen functional group can bond to carbon black and the carbon-carbon double bond moiety can bond to the rubber polymer. In formula (I), R ¹ and R ² are preferably hydrogen atoms. It is preferred that M ⁺ be 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 the step of mixing the rubber latex and the carbon black slurry after addition to obtain a rubber latex before coagulation 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. As carbon black, for example, conductive carbon black such as acetylene black and ketjen black can be used in addition to SAF, ISAF, HAF, FEF, GPF and the like. The carbon black may be granulated carbon black granulated in consideration of its handling property, or may be non-granulated carbon black. The amount of carbon black in the carbon black slurry is preferably 1% by mass or more, more preferably 3% by mass or more, in 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 the addition, the rubber latex and the carbon black slurry can be mixed by a general dispersing machine such as a high shear mixer, homomixer, ball mill, bead mill, high pressure homogenizer, ultrasonic homogenizer, colloid mill and the like.

  The method of manufacturing a tire according to the first embodiment includes the steps of coagulating the rubber latex before 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. The coagulated material obtained by coagulating the rubber latex before coagulation treatment contains water. This step can include dewatering the coagulum and plasticizing while drying. In this step, the coagulated material can be dewatered by pressing and evaporation using an extruder, and after dewatering can be plasticized while being dried. As an extruder, a single screw extruder can be mentioned, for example. 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 the 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, and still more preferably 100% by mass in 100% by mass of the 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 still more 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, with respect to 100 parts by mass of rubber. The amount of the compound of formula (I) in the masterbatch can be at least 0.05 parts by weight, based on 100 parts by weight of rubber. The amount of the compound of formula (I) in the masterbatch can be up to 10 parts by weight with respect to 100 parts by weight of rubber.

  The method for manufacturing a tire according to the first embodiment includes the step of kneading at least a masterbatch and a compounding agent to obtain a mixture. As the compounding agent, carbon black, zinc oxide, stearic acid, anti-aging agent and the like can be mentioned. One or more of these can be selected and kneaded with the master batch. When carbon black is added at the time of kneading, for example, conductive carbon blacks such as acetylene black and ketjen black can be used as the carbon black in addition to SAF, ISAF, HAF, FEF, GPF and the like. The carbon black may be granulated carbon black granulated in consideration of its handling property, or may be non-granulated carbon black. The grade of carbon black added at the time of kneading may be the same as or different from the grade of carbon black in the master batch by ASTM (American Society for Testing and Materials). By adding carbon black at the time of kneading, adhesion of the compounding agent to the kneading machine (for example, adhesion of the compounding agent to the chamber wall in the case of a Banbury mixer) can be suppressed, and the compounding agent by rubber Can improve the uptake of 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 can be mentioned. In the kneading step, other rubbers can be kneaded together with the masterbatch and the compounding agent. Examples of the rubber added to the masterbatch at the time of kneading include natural rubber, polyisoprene rubber, styrene-butadiene rubber, nitrile rubber, chloroprene rubber and the like. Kneading can be performed by a closed mixer. A Banbury mixer, a kneader etc. can be mentioned as a closed type mixer.

  The method of manufacturing a tire according to the first embodiment further includes the step of kneading the vulcanizing compounding agent into the mixture to obtain a rubber composition. Examples of the vulcanizing compounding agent include sulfur, vulcanizing agents such as organic peroxides, vulcanization accelerators, vulcanization acceleration assistants, vulcanization retarders, and the like. Examples of sulfur include powdered sulfur, precipitated sulfur, insoluble sulfur, highly dispersible sulfur and the like. 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 accelerator And the like.

  The rubber composition comprises a rubber derived from a 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 based on 100% by mass of the rubber in the rubber composition. It can be 100% by weight.

  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, with respect to 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 based on 100 parts by mass of the rubber in the rubber composition.

  The rubber composition 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 still more preferably 30 parts by mass or more with respect to 100 parts by mass of the 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 the rubber in the rubber composition.

  The rubber composition can further include stearic acid, zinc oxide, an antiaging agent, sulfur, a vulcanization accelerator 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 the rubber in the rubber composition. The amount of the vulcanization accelerator is preferably 0.1 parts by mass to 5 parts by mass with respect to 100 parts by mass of the rubber in the rubber composition.

  The rubber composition can be used to make a tire. Specifically, it can be used for preparation of a tire member which constitutes a tire, and can be used for preparation of sidewall rubber, tread rubber, etc., for example.

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

Modification 1
In the tire manufacturing method according to the first embodiment, carbon black is added to water and stirred in order to obtain a carbon black slurry, but in the first modification, carbon black is added to the diluted rubber latex and stirred. The diluted rubber latex can be obtained, for example, by adding water to the rubber latex. The rubber latex used to make the diluted rubber latex is, for example, a natural rubber latex, a synthetic rubber latex or the like. The number average molecular weight of the natural rubber in the natural rubber latex is, for example, 2,000,000 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 diluted rubber latex is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, and still more 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.

Raw materials and chemicals are shown below.
Natural rubber latex NR Field latex (31.2% of dry rubber content) manufactured by Golden Hope
Natural rubber RSS # 3
Carbon black "Siest 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-butenoate sodium ( Compounds of Formula (I '))
Zinc Flower "Zinc Flower Type 1" Mitsui Metal Co., Ltd. Stearic Acid "Lunak S-20" Kao Corporation Anti-aging Agent "Antigen 6C" (N-phenyl-N '-(1,3-dimethylbutyl) -p-phenylene Diamines) Sumitomo Chemical Co., Ltd. Sulfur "5% oil-filled fine powder sulfur" Tsurumi Chemical Industry Co., Ltd. Vulcanization accelerator "Sunseller NS-G" Sanshin Chemical Industries Co., Ltd.

Preparation of Rubber A 3 parts by mass of Compound 1 was added to a natural rubber latex with respect to 100 parts by mass of dry rubber, and the mixture was thinly poured 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 of 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 dry rubber content of the natural rubber latex, to obtain a rubber latex before coagulation treatment. Formic acid as a coagulant was added to the rubber latex before coagulation treatment until pH 4 was obtained to obtain a coagulum. The coagulated material was dewatered and plasticized while being dried by a screw press Model V-02 (squeezer type single-screw extrusion / dehydrator) manufactured by Suehiro EPM to obtain a wet master batch A.

Preparation of Wet Master Batch B 3 parts by mass of Compound 1 was added to natural rubber latex with respect to 100 parts by mass of the dry rubber content of natural rubber latex, and after addition, a rubber latex was prepared. On the other hand, carbon black was added to water and stirred to prepare a carbon black slurry of 6% by mass of carbon black. The carbon black slurry and the natural rubber latex after addition were mixed so as to be 35 parts by mass of carbon black with respect to 100 parts by mass of the dry rubber content of the natural rubber latex after addition, to obtain a rubber latex before coagulation treatment. Formic acid as a coagulant was added to the rubber latex before coagulation treatment until pH 4 was obtained to obtain a coagulum. The coagulated material was dewatered and plasticized while being dried by a screw press Model V-02 (squeezer type single-screw extrusion dehydrator) manufactured by Suehiro EPM to obtain a wet master batch B.

Preparation of rubber B 0.5 parts by mass of the compound 1 was added to natural rubber latex with respect to 100 parts by mass of dry rubber, and the mixture was thinly poured on a tray and dried at room temperature to obtain rubber B.

Preparation of wet master batch C 0.5 parts by mass of the compound 1 was added to natural rubber latex with respect to 100 parts by mass of dry rubber of natural rubber latex, and after addition, a rubber latex was prepared. On the other hand, carbon black was added to water and stirred to prepare a carbon black slurry of 6% by mass of carbon black. The carbon black slurry and the natural rubber latex after addition were mixed so as to be 35 parts by mass of carbon black with respect to 100 parts by mass of the dry rubber content of the natural rubber latex after addition, to obtain a rubber latex before coagulation treatment. Formic acid as a coagulant was added to the rubber latex before coagulation treatment until pH 4 was obtained to obtain a coagulum. The coagulated material was dewatered and plasticized while being dried by a screw press Model V-02 (squeezer type single screw extruder / dewaterer) manufactured by Suehiro EPM to obtain a wet master batch C.

Preparation of Unvulcanized Rubber Compounding agents other than sulfur and a vulcanization accelerator were added to the rubber according to Table 1 and kneaded with a B-type Banbury mixer manufactured by Kobe Steel Co., Ltd. to discharge the rubber mixture. The rubber mixture, sulfur and vulcanization accelerator were kneaded with a B-type Banbury mixer to obtain an unvulcanized rubber.

Tensile strength at break of vulcanized rubber (TS)
The unvulcanized rubber was vulcanized at 150 ° C. for 30 minutes, and a tensile property test was carried out according to JIS K6251: 2010 to measure the tensile strength at break. In Table 1, the value of each example is shown by an index with the value of Comparative Example 1 being 100. The larger the index, the better the tensile strength at break.

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

Claims (3)

Adding a compound of the following formula (I) to the rubber latex and obtaining the rubber latex after the addition;
Mixing the rubber latex and the carbon black slurry after the addition.
Masterbatch production 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, and M ⁺ represents sodium ion, potassium ion or lithium ion.)   The manufacturing method of the rubber composition for tires containing the manufacturing method of the masterbatch of Claim 1. A method of manufacturing a tire, comprising the method of manufacturing a masterbatch according to claim 1.