1. Raw rubber plasticizing
The processing technology of rubber has certain requirements on the plasticity of raw rubber. In order to meet the technical performance, raw rubber must be plasticated. However, most synthetic rubbers control the initial plasticability of raw rubber in the process of synthesis. In addition, natural rubber, hard butadiene rubber, isoprene rubber, styrene-butadiene rubber and so on all need to be tempered properly.
Plasticizing can reduce the drilling degree of rubber and make the compound easy to mix. Plasticizing can improve the rheological properties of rubber, reduce mouth expansion and calendering shrinkage. Plasticizing can also improve the solubility of rubber and forming drill ability. Plasticizing must be moderate, excessive plasticizing will reduce the strength, elasticity, abrasion resistance and aging resistance of vulcanized rubber. The degree of plasticization is mainly determined according to the technological properties of the compound and the requirements of the product. The plastic refining of raw rubber is usually carried out on the open rubber refining machine, but it can also be carried out on the closed rubber refining machine.
2, cooperate with
According to the practical rubber material formulation of raw rubber and the dosage of various additives for accurate weighing.
Mixing is a process in which various compounding agents are pressed together with raw rubber on a rubber mixer. Mixing is not only a simple mechanical mixing process of raw rubber and coordination agent, but also a physical and chemical process in which various components are infiltrated, dispersed, adsorbed and combined to form colloidal dispersion with complex network structure, which is actually a rubber modification process.
In the whole process of rubber processing, the quality of mixing rubber has a decisive influence on the further processing of rubber and the performance of the final product. If the mixing is not good, the compound will appear uneven dispersion, plastic fluctuation, even burning, spray frost phenomenon, resulting in vulcanized rubber and product performance decline.
Mixing can be carried out on a mixer or mixer. For small size, less batch, frequent variety of rubber material, use mixing mill. In addition, the mixing machine is also specially suitable for the preparation of some special rubber materials, such as sponge rubber, hard rubber, buching rubber, atmosphere rubber and so on. The compound mixed by the mixer must be stored for 4-8h before it is processed on the mixer with accelerant and vulcanizing agent.
4. Semi-finished product preparation
O - type rubber seal ring production is generally still to die - press production. In order to improve production efficiency and product quality and reduce waste, pre-manufacturing of semi-finished products is necessary. The manufacturing process of the traditional plate vulcanization semi-finished products is that the qualified mixing rubber is pressed into film after full refining, cutting into strips and blocks. For the products with large quantity or large specification, the extruder L can be extruded into rubber rope according to the required specifications, cut to a certain length, joint by 45, lap, to make o-ring semi-finished products. In recent years, many domestic manufacturers have adopted precision preforming machines to produce o-rings and other semi-finished products. This not only improves the production efficiency, but also guarantees the volume and weight accuracy of semi-finished products, and improves the production technology of rubber products. With injection molding machine production, semi-finished products do not need special preparation, just press the good rubber strip directly feeding can be.
5, the last step is the rubber seal ring vulcanization