Rubber products made from natural rubber have high mechanical strength, good elasticity, but high cost. They are often used in conjunction with renewable resources such as latex recycled rubber and tire recycled rubber to reduce cost and improve rubber process performance. The open mill is natural rubber / recycled rubber. One of the most commonly used rubber mixing equipment in the mixing process is essentially different from the mixer mixing. It is necessary to strictly control the operation of the rubber mixing process to ensure the quality of natural rubber / recycled rubber mixing and ensure the subsequent production process. .
1. Control the roller distance of the open mill: When natural rubber / recycled rubber is used and the rubber is mixed in the open mill, the mixing process is usually carried out in the smaller roller distance first, and then the roller distance of the open mill is increased. .
2. Even distribution of compounding agent: During natural rubber / recycled rubber compounding process, the operator needs to uniformly extend the length of the compounding roller before adding the compounding agent (mainly powdery compounding agent and liquid compounding agent). Distribution to improve the mixing effect of natural rubber / recycled rubber in the open mill.
3. Control the adding method of the compounding agent: The amount of the compounding agent in the natural rubber / recycled rubber compound formula varies. For some compounding agents with a small amount, it is best to add it in the form of ointment during mixing. To ensure that these compounding agents can be evenly dispersed in natural rubber / recycled rubber and used rubber.
4. Control the feeding order: The feeding order directly affects the quality of natural rubber / recycled rubber mixing rubber, so the mixing order of the rubber and various compounding agents must be strictly controlled when performing the mixing operation in the open mill.
① Adding order of natural rubber / recycled rubber
Compared with natural rubber, the fluidity and plasticity of recycled rubber have advantages in themselves. Therefore, when natural rubber and recycled rubber are used together to produce rubber products, natural rubber is usually added to the open mill to the roll. In theory, natural rubber with a relatively high viscosity is added first, and then recycled rubber is gradually added.
② Adding order of various compounding agents
Natural rubber / recycled rubber in the compounding process, in general, after adding natural rubber and recycled rubber, stearic acid, accelerators, active agents and other complexing agents are added; for larger amounts of reinforcing agents and fillers, Generally, it is added in batches to ensure that the reinforcing agent and filler are evenly dispersed in the rubber compound; the plasticizer is usually added after the addition of the reinforcing agent and filler, but many manufacturers avoid mixing natural rubber and recycled rubber. Problems such as too high hardness and high energy consumption during mixing occur. Many softeners and plasticizers are added after adding some fillers; vulcanizing agents are added before the end of natural rubber / recycled rubber and rubber mixing process to avoid Early vulcanization problems arise.
5. Control the operating conditions of the mixing process: During the natural rubber / recycled rubber mixed rubber compounding process, the feeding order and production process parameters will affect the physical indicators and process performance of the rubber compound. Rubber product manufacturers need to strictly control the mixing according to the test results. The process mainly includes mixing time, mixing pressure, and mixing temperature.
The use of recycled rubber in natural rubber can not only reduce the production cost, but also improve the technical performance and vulcanization performance of natural rubber. The rubber product manufacturers can choose the appropriate recycled rubber and use it according to actual needs. The amount of recycled rubber can be reasonably determined. Strictly control the mixing process during machine mixing to ensure that the natural rubber / recycled rubber mixing rubber is fully and uniformly mixed.