DTDM curing agent in tire rubber layer inside and outside the compound

At present, the prevalence of high-speed and overloading of vehicles running on the state of bias truck tire inner quality of a higher demand, particularly to avoid traveling for a long time in the process of deformation due to fatigue caused by heat so that the rubber and plastic interface Cord material and have a combined surface damage caused by the phenomenon of shoulder space. I plant the production of tire components will be stretched by the stress of inner-child to the crown in order to increase (was "stepped"), but because of the original, the outer layer of rubber stretch stress will be lower (inner layer of rubber in the 4 ~ 5MPa, in the outer layer of rubber 6MPa around), and expect that stretch rubber buffer layer of stress (10MPa or so) big difference, so that the moving tire easily because of lack of over-rigid deformation. It is therefore necessary for the tire, the outer layer of rubber formula to re-design, improve the appropriate set of rubber stretch stress.
Original tires, the outer layer of rubber formulations using ordinary curing systems, which are vulcanized at the time of cross-linked structure of the main keys to more sulfur, and sulfur multi-button key to small, unstable and prone to change, so the heat aging Poor performance in the use of tire easily in the process of reversion phenomenon, affecting the actual useful life of tires. To this end, we decided to tire, the outer layer of rubber formulations used in semi-effective curing system, the key cross-linked to a single button and sulfur-based two-sulfur bond, thereby reducing the heat of rubber, plastic materials to improve the thermal stability And anti-reversion mice; at the same time improved the set of rubber stretch stress, so they do not increase the amount of carbon black under the premise can, the outer layer of rubber stretch stress will be improved to meet the design requirements. In the choice of semi-effective system for curing when curing agent selected DTDM with the promoter and NOBS. DTDM sulfur curing agent mass fraction of about 0 27 in the curing temperature can break out of active sulfur, and safe operation, and used some of the curing agent can be used to increase the speed of vulcanization.
Experiment 1
1.1 raw materials
NR, grade SIR20 #, Indonesia imported products; BR, Beijing Yanshan Petrochemical Company's products; SBR, Grade 1500, Jilin Chemical Industrial Products Co., Ltd.; SBR, Grade 1712, Lanzhou Chemical Industry Company's products; curing agent DTDM, Shanghai, Beijing Chemical Industry sea Products Co., Ltd.; accelerator NOBS, Zhejiang Yongjia chemical products; 60 heads of fine powder, Ltd. Jiande renewable Fenghua rubber products; other raw materials used for the rubber industry.
1.2 the basic formula
1.2.1 outer rubber formula
(1) formula A (original recipe): NR 90; SBR1500 10; sulfur and promoter (M + DM + TMTD) 3. 7; carbon black (N330 + semi-reinforcing + N660) 40; softeners 5; antioxidant 2.5; other 7.7, Total 158.9. (2) Formula B: NR 90; SBR1500 10; sulfur, DTDM curing agent and promoter (NOBS + M) 3.37; carbon black (N330 + semi-reinforcing + N660) and silica 41; softeners 5; antioxidant 2.5 ; Other 7.7 Total 159 57.
(3) formula C: NR 90; SBR1500 10; sulfur, DTDM curing agent and promoter (NOBS + M) 3 37; Carbon Black (N330 + semi-reinforcing + N660) 40; softeners 5; antioxidant 2.5; other 7.7, Total 158.57.
(4) Formula D: NR 90; SBR1500 10; sulfur, DTDM curing agent and promoter (NOBS + M) 3 37; carbon black (N326 + semi-reinforcing + N660) and silica 41; softeners 5; antioxidant 2.5; other 7.7 Total 159 57.
(5) formula E: NR 90; SBR1500 10; sulfur, DTDM curing agent and promoter (NOBS + M) 3.37; carbon black (N326 + semi-reinforcing + N660) 40; softeners 5; antioxidant 2.5; other 7.7 A total of 158 57.
1.2.2 inner layer of rubber formula
(1) formula A '(original recipe): NR 80; BR 10; SBR1500 10; sulfide and sulfur agent (M + DM + TMTD) 3 46; carbon black (N330 + N660 + semi-reinforcing + MT) 43; softening 7 agent; antioxidant 2 8; other 7 25, total 163 51.
(2) Formula B ': NR 80; BR 10; SBR1500 10; sulfur, DTDM curing agent and promoter (NOBS + M) 3.14; carbon black (N330 + N660 + semi-reinforcing + MT) 43; softeners 5; Antioxidant 2.8; other 7 7, total 161 64.
(3) formula C ': NR 80; BR 10; SBR1500 10; sulfur, DTDM curing agent and promoter (NOBS + M) 3 14; carbon black (N326 + N660 + reinforcement and a half) 38; powder 5; softening 5 agents; antioxidant 2 8; other 7 7, total 161 64.
(4) formula D ': NR 80; BR 10; SBR1712 10; sulfur, DTDM curing agent and promoter (NOBS + M) 3 34; carbon black (N326 + N660 + semi-reinforcing + MT) 43; powder 5 ; Softeners 5; antioxidant 2.8; other 7.7 Total 166 84.
1.3 The main apparatus and equipment
150mm × 320mm Lian-opened, the city of Wuxi Rubber & Plastics Machinery Plant products; XM 140 mixer, the tip of the Dalian Rubber and Plastic Products Co., Ltd.; 50t hydraulic flat-curing, rubber-fu and Zhejiang Pinghu plant products; R100E curing device, Beijing Friends of the electronic instrument factory city of Shenzhen products; WGJ 2500B computer controlled optical tracking pull test, Guangxi Normal University Xiufeng electrical plant products; TWC 2 T / B (Y) test the durability of tires, wheels, Tianjin Jiurong Technology Co., Ltd. products.
1.4 Preparation of rubber
(1) indoor tests with a small rubber used to open chain mixing machine. Charging order: rubber antioxidant → fine carbon black material → → → oil promoter, curing agent, sulfur. Thin-3 after the relaxation of the roll from the back-up Xiapian.
(2) pilot plant with large rubber mixer used for mixing a section, the mixing process: Health 2min thin plastic material, 1 / 2 black 3min1 / 2 carbon black, oil 3min promoter, curing agent 1min row Plastic. Sulfur pressure in the film crew to join.
1.5 Performance Test
The physical properties of rubber by the determination of the appropriate national standards.
2 and the outcome of discussions
2.1 outer rubber test
2.1.1 with a small test
Formula B, C, D and E are used DTDM curing agent and promoter of the semi-NOBS effectively curing systems, greatly reducing the amount of sulfur. In order to lower the heat rubber, Formula B and D are also adding a small amount of precipitated silica; due to lower heat, Formula D and E will be replaced by carbon black N330 carbon black N326. Outer layer of rubber with a small test results in table 1.
As can be seen from Table 1, compared with the original formula, 4-Test rubber formula of 300% will be stretched to a greater degree of stress has increased, 9MPa to meet the basic requirements of the design. And that DTDM and a half due to the effective curing systems, the extension of the scorch time, to improve the performance of rubber processing.
2.1.2 workshop with big test
Through the test with a small, select Formula A, D and E to carry out large workshop with the pilot, rubber cord in the four-high rolling on the calendar, the formula test performance than the original formulation process rubber improved in the same process conditions, the cord calendar Lower temperature, and in the past when some familiar skin also disappeared. The results in table 2.
As can be seen from Table 2, the physical properties of rubber and the fundamental test with the same small, and the rubber cord and the bonding strength than the original formula has increased, scorch the extension of the time. D and E as compared formula, which more or less the same physical properties, consider the ingredients of the process is easy to operate, will determine the formula for the expansion of E test, after a trial to reflect on the good results, the final formula by the end of 1999 to come into operation生产.

2.2 inner rubber test
2.2.1 with a small test
According to the formula of the outer design, the inner layer of the formula have also been adjusted, with its small test results in table 3. DTDM more expensive due to the curing agent, in order to obtain better economic results, SBR, and the powder MT contrast test, in which D prescription lowest cost, and can be seen from Table 3, D prescription physical properties of rubber to meet the requirements.
2.2.2 workshop with big test
Through with a small pilot plant for D sure formula with great test results in table 4. It can be seen, D prescription rubber of the physical properties are in line with the request. Formula D in April 2000 formally put into production.
3 product performance
Changes in the formula after the product performance tire test results in table 5 and 6, respectively. Table 5 and 6 can be seen using the formula D finished tire machine running longer than the original formula nearly 20h; 9 00-2016PR specifications of the finished tire ply between the bonding strength than the original recipe is basically slightly.



4, cost-effective
Adjustment formula, I plant in 2000 over the previous year to reduce the amount of the return of more than 1,000 million, of which as a result of changes in the formula to reduce the amount of restitution of 200 million yuan, showing a new formula has a good economic and social benefits.
5 Conclusion
(1) of the rubber layer inside and outside the formula used DTDM-effective curing systems, to improve the rubber set stretch stress, the entire set tires stretching more rational allocation of stress. Due to appropriately raise the carcass of a rigid, to reduce shoulder strain, reduce heat, reduce air shoulder defect disease, thus reducing the annual return of the amount of 200 million yuan.
(2) due to the introduction of a new curing systems and low-carbon heat and extended the rubber scorch time, the production process to improve the processing technology to reduce consumption, lower production costs. Thanks: LUO Guang Xiang has been working vigorously to help engineers, and would like to express my sincere gratitude.