High-temperature rapid vulcanization is a characteristic of rubber injection technology. When using reclaimed rubber to produce injection-type rubber products, the rubber product manufacturer must ensure that the rubber has sufficient scorch time; the rubber should be quickly vulcanized when it enters the mold cavity. It will soon reach positive vulcanization; therefore, manufacturers of reclaimed rubber products need to design a vulcanization process reasonably to meet the needs of injection molding reclaimed rubber products.
1. Selection of vulcanizing agent for injection-type reclaimed rubber products
Commonly used vulcanizing agents in the production of reclaimed rubber products include sulfur, sulfur donors, peroxides, and metal oxides. When using reclaimed rubber to produce rubber products, there are strict requirements on the scorchability, vulcanization rate, and high temperature resistance of 2YLYY317. Generally, an effective vulcanization system or sulfur-free vulcanization is selected. Sulfur should be avoided as much as possible. If necessary, a sulfur donor (DTDM) ) Replace.
In actual production, the traditional sulfur vulcanization system will undergo a crosslinking bond shortening reaction at a higher temperature, the degree of modification of the main chain will increase, the distribution of crosslinking bonds will change, and the sulfur vulcanization efficiency will decrease.
Effective vulcanization system After vulcanization, the rubber compound has good antigenicity and vulcanization uniformity. The vulcanized rubber has good compression deformation resistance and low heat generation. It is suitable for the injection process of reclaimed rubber. The crosslink density during the vulcanization process is due to the increase of vulcanization temperature reduce. The distribution of internal cross-linking bonds of the rubber compound vulcanized by the non-sulfur vulcanization system changes much less at high temperature than the traditional sulfur vulcanization system, which is more advantageous for injection molding.
2. Selection of accelerators for injection-type reclaimed rubber products
Vulcanization accelerators can play multiple roles in shortening the vulcanization time, lowering the vulcanization temperature, and reducing the amount of vulcanizing agent in the production of rubber products. The rational use of accelerators can further improve the physical and mechanical properties of the products.
When the injection-type reclaimed rubber products are vulcanized with sulfur donors, sulfenamide accelerators such as MBS and accelerators TMTD can be used together to form a sulfur-free vulcanization system at a ratio of 1:1:1. Or use the thiazole accelerator DM and the sulfenamide accelerator CZ together in the effective vulcanization system, and avoid the use of the thiuram accelerator TMTD, which has a fast start of vulcanization, to avoid the occurrence of over-sulfur and under-sulfur problems.
Natural rubber, butadiene rubber and reclaimed rubber are used together to produce injection-type reclaimed rubber products, and most choose a sulfur-free vulcanization system; when reclaimed rubber is used together with isoprene rubber, and styrene butadiene rubber, it is better to choose an effective vulcanization system. When using reclaimed rubber to produce injection-type rubber products, rubber product manufacturers need to choose a suitable vulcanization system according to the types of reclaimed rubber and the specific needs of rubber products. It should be noted that in the injection-type reclaimed rubber vulcanization system, reclaimed rubber injection products require sufficient amounts of zinc oxide and stearic acid to further improve the comprehensive indicators of reclaimed rubber injection products. Fatty acid.
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