Tire member manufacturing method and tire manufacturing method

Abstract

A first tire member manufacturing method includes an operation in which a master batch is made, and an operation in which the master batch, peptizing agent, and processing additive are mixed. The operation in which the master batch is made includes an operation in which carbon-black-containing pre-coagulation rubber latex is coagulated to obtain a coagulum, an operation in which a compound according to Formula (I), below, is added to the water-containing coagulum, and an operation in which the compound according to Formula (I) is dispersed within the coagulum. ##STR00001## In Formula (I), R.sup.1 and R.sup.2 each indicates a hydrogen atom, an alkyl group having 1 to 20 carbons, an alkenyl group having 1 to 20 carbons, or an alkynyl group having 1 to 20 carbons. R.sup.1 and R.sup.2 may be the same or different. M.sup.+ indicates sodium ion, potassium ion, or lithium ion.

Claims

1. A tire member manufacturing method comprising: an operation in which a master batch is made; and an operation in which the master batch and peptizing agent and processing additive are mixed; wherein the operation in which the master batch is made comprises an operation in which carbon-black-containing pre-coagulation rubber latex is coagulated to obtain a coagulum; an operation in which a compound according to Formula (I), below, is added to the water-containing coagulum; and an operation in which the compound is dispersed within the coagulum; wherein Formula (I) is given by ##STR00005## and wherein, at Formula (I), R.sup.1 and R.sup.2 each indicates a hydrogen atom, an alkyl group having 1 to 20 carbons, an alkenyl group having 1 to 20 carbons, or an alkynyl group having 1 to 20 carbons; R.sup.1 and R.sup.2 may be the same or different; and M.sup.+ indicates sodium ion, potassium ion, or lithium ion.

2. The tire member manufacturing method according to claim 1 wherein the operation in which the compound is dispersed within the coagulum is an operation in which the compound is dispersed within the coagulum as the coagulum is being dewatered.

3. The tire member manufacturing method according to claim 1 wherein, at the operation in which the compound is added to the coagulum, taking the amount of water in the coagulum for every 100 parts by mass of rubber within the coagulum to be Wa, and taking the amount of the compound that is added for every 100 parts by mass of rubber within the coagulum to be Wb, Wa/Wb, being the ratio of Wa to Wb, is in a range that is 1 to 8100.

4. A tire manufacturing method comprising the tire member manufacturing method according to claim 1.

5. A tire member manufacturing method comprising: an operation in which a master batch is made; and an operation in which the master batch and peptizing agent and processing additive are mixed; wherein the operation in which the master batch is made comprises an operation in which a compound according to Formula (I), below, is added to a mixture comprising carbon black and rubber; and an operation in which the compound is dispersed within the mixture in the presence of water; wherein Formula (I) is given by ##STR00006## and wherein, at Formula (I), R.sup.1 and R.sup.2 each indicates a hydrogen atom, an alkyl group having 1 to 20 carbons, an alkenyl group having 1 to 20 carbons, or an alkynyl group having 1 to 20 carbons; R.sup.1 and R.sup.2 may be the same or different; and M.sup.+ indicates sodium ion, potassium ion, or lithium ion.

6. A tire manufacturing method comprising the tire member manufacturing method according to claim 5.

Description

WORKING EXAMPLES

(1) Working examples in accordance with the present disclosure are described below.

(2) Raw materials and reagents are indicated below.

(3) TABLE-US-00001 Natural rubber latex (dry Manufactured by Golden Hope rubber content = 31.2%) Coagulant Formic acid (reagent-grade 85%) manufactured by Nacalai Tesque, Inc. (diluted to obtain 10% solution and pH adjusted to 1.2 prior to use) Carbon black SEAST SO manufactured by Tokai Carbon Co., Ltd. Compound 1 (2Z)-4-[(4-aminophenyl)amino]-4-oxo-2- butene acid sodium (compound according to Formula (I)) manufactured by Sumitomo Chemical Co., Ltd. Zinc oxide Zinc Oxide No. 1 manufactured by Mitsui Mining Stearic acid LUNAC S-20 manufactured by Kao Corporation Wax OZOACE 0355 manufactured by Nippon Seiro Co., Ltd. Antioxidant 6PPD (N-phenyl-N-(1,3-dimethylbutyl)- p-phenylenediamine) manufactured by Monsanto Company Peptizing agent Noctizer SD manufactured by Ouchi Shinko Chemical Industrial Co., Ltd. Processing Additive 1 Aktiplast MS (mixture of DBD and fatty acid zinc salt; DBD content = 5 mass % to 10 mass %; fatty acid primary constituent is saturated fatty acid having 18 carbons) manufactured by Rhein Chemie Processing Additive 2 Aktiplast PP (fatty acid zinc salt) manufactured by Rhein Chemie Processing Additive 3 Struktol WB16 (mixture of calcium soap and saturated fatty acid amide) manufactured by S&S Japan Co., Ltd. Sulfur 5% Oil Treated Sulfur Powder manufactured by Tsurumi Chemical Industry Co., Ltd. Vulcanization accelerator Sanceler NS-G (N-(tert-butyl)-2- benzothiazolesulfenamide) manufactured by Sanshin Chemical Industry Co., Ltd.

Preparation of Wet Master Batch at Working Examples 1 Through 7 and at Comparative Examples 5 Through 8

(4) Water was added at 25 C. to concentrated natural rubber latex to obtain a dilute natural rubber latex having a solids (rubber) concentration that was 0.52 mass %, and a natural rubber latex having a solids (rubber) concentration that was 28 mass %. 50 parts by mass of carbon black was added to 954.8 parts by mass of the dilute natural rubber latex, and a ROBO MIX manufactured by PRIMIX Corporation was used to agitate the post-addition-of-carbon-black dilute natural rubber latex to obtain a carbon black/natural rubber slurry. The carbon black/natural rubber slurry was added to the natural rubber latex having the solids (rubber) concentration that was 28 mass % in accordance with TABLE 1, and a mixer for household use manufactured by SANYO was used to agitate the post-addition-of-carbon-black/natural-rubber-slurry natural rubber latex at 11300 rpm for 30 min to obtain a pre-coagulation rubber latex. Formic acid serving as coagulant was added to the pre-coagulation rubber latex in an amount sufficient to achieve a pH of 4, and a filter was used to separate the coagulum from waste liquid. Compound 1 was added to the coagulum, and Compound 1 was dispersed within the coagulum as a Model V-02 screw press (squeezer-type single-screw dewatering extruder) manufactured by Suehiro EPM Corporation was used to dewater/plasticize at 180 C. the post-addition-of-Compound-1 coagulum. As a result of the foregoing procedure, a wet master batch was obtained.

Preparation of Wet Master Batch at Comparative Examples 1 Through 4, Comparative Example 9, and Comparative Example 11

(5) Except for the fact that Compound 1 was not added to the coagulum, a procedure identical to that of Working Example 1 was used to obtain the wet master batch of Comparative Examples 1 Through 4, Comparative Example 9, and Comparative Example 11.

Preparation of Wet Master Batch at Comparative Examples 10 and 12

(6) Except for the fact that the coagulum was substantially completely dewatered prior to addition of the Compound 1 to the coagulum, a procedure identical to that of Working Example 1 was used to prepare the wet master batch of Comparative Examples 10 and 12.

Preparation of Unvulcanized Rubber at the Various Examples

(7) The compounding ingredients except for sulfur and vulcanization accelerator were added in accordance with TABLE 1, a Model B Banbury mixer manufactured by Kobe Steel, Ltd., was used to carry out kneading, and the rubber mixture was discharged. The rubber mixture was then kneaded together with sulfur and vulcanization accelerator in a Model B Banbury mixer to obtain unvulcanized rubber.

(8) Mooney Viscosity Index

(9) Mooney viscosity of the unvulcanized rubber as it existed immediately following manufacture was measured in accordance with JIS K-6300-1, the Mooney viscosity being shown as indexed relative to a value of 100 for Comparative Example 1. The lower the index the lower the Mooney viscosity and the more excellent the workability.

(10) Storage Stability

(11) Storage stability of unvulcanized rubber was evaluated based on the criterion of Mooney viscosity. More specifically, Mooney viscosity of the unvulcanized rubber as it existed immediately following manufacture was measured in accordance with JIS K-6300-1, and Mooney viscosity was measured again after storing the unvulcanized rubber for 3 months at standard temperature (23 C.2 C.). Post-storage Mooney viscosity is shown as indexed relative to a value of 100 for the Mooney viscosity as it existed immediately following manufacture. The closer the index is to 100 the more excellent the storage stability of the unvulcanized rubber.

(12) TABLE-US-00002 TABLE 1 Comparative Example 1 2 3 4 5 6 7 8 9 10 11 12 Manufacture Parts by mass Natural rubber 100 100 100 100 100 100 100 100 100 100 100 100 wet master (solids content) batch Carbon black 45 45 45 45 45 45 45 45 45 45 45 45 Compound 1 2 2 2 2 2 2 Water content (parts by mass) of 200 200 200 200 200 200 200 200 200 200 coagulum at time of addition of Compound 1 Wa/Wb 100 100 100 100 Manufacture Parts by mass Wet master batch 145 145 145 145 147 147 147 147 145 147 145 147 unvulcanized Compound 1 2 2 rubber Zinc oxide 3 3 3 3 3 3 3 3 3 3 3 3 Stearic acid 2 2 2 2 2 2 2 2 2 2 2 2 Wax 2 2 2 2 2 2 2 2 2 2 2 2 Antioxidant 2 2 2 2 2 2 2 2 2 2 2 2 Peptizing agent 0.2 Processing 2 2 2 Additive 1 Processing 2 2 Additive 2 Processing 2 2 Additive 3 Sulfur 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 Vulcanization 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 accelerator Mooney viscosity index 100 91 95 97 121 118 107 108 125 128 116 120 Storage stability index 120 121 122 123 110 102 111 109 118 116 120 117 Working Example 1 2 3 4 5 6 7 Manufacture Parts by mass Natural rubber 100 100 100 100 100 100 100 wet master (solids content) batch Carbon black 45 45 45 45 45 45 45 Compound 1 2 2 2 2 2 2 2 Water content (parts by mass) of 200 4 10000 200 200 200 200 coagulum at time of addition of Compound 1 Wa/Wb 100 2 5000 100 100 100 100 Manufacture Parts by mass Wet master batch 147 147 147 147 147 147 147 unvulcanized Compound 1 rubber Zinc oxide 3 3 3 3 3 3 3 Stearic acid 2 2 2 2 2 2 2 Wax 2 2 2 2 2 2 2 Antioxidant 2 2 2 2 2 2 2 Peptizing agent 0.2 0.2 Processing 2 2 2 1 3 Additive 1 Processing 2 Additive 2 Processing 2 Additive 3 Sulfur 1.5 1.5 1.5 1.5 1.5 1.5 1.5 Vulcanization 0.5 0.5 0.5 0.5 0.5 0.5 0.5 accelerator Mooney viscosity index 102 103 102 110 92 104 104 Storage stability index 102 101 101 103 102 103 102

(13) Combined use of Compound 1 and Processing Additive 1 caused improvement of storage stability. Use of Compound 1 alone caused improvement of storage stability in an amount corresponding to 10 points (see Comparative Example 1 and Comparative Example 5). Use of Processing Additive 1 alone caused worsening of storage stability in an amount corresponding to 1 point (see Comparative Example 1 and Comparative Example 2). On the other hand, combined use of Compound 1 and Processing Additive 1 caused improvement of storage stability in an amount corresponding to 18 points (see Comparative Example 1 and Working Example 1).

(14) Processing Additive 1 was effective in suppressing the increase in Mooney viscosity that would otherwise have occurred due to Compound 1. Use of Compound 1 alone caused increase in Mooney viscosity in an amount corresponding to 21 points (see Comparative Example 1 and Comparative Example 5). Use of Processing Additive 1 alone caused decrease in Mooney viscosity in an amount corresponding to 9 points (see Comparative Example 1 and Comparative Example 2). On the other hand, combined use of Compound 1 and Processing Additive 1 caused increase in Mooney viscosity in an amount corresponding to a mere 2 points (see Comparative Example 1 and Working Example 1).