1. The formation of raw rubber

  Raw rubber can be divided into two categories: natural rubber and synthetic rubber:

  (1) Natural rubber: The raw rubber is formed by cutting the rubber trunk, collecting the glue that flows out, and going through the processing procedures of impurity removal, coagulation, smoking, and drying.

  (2)Synthetic rubber: By-products produced by the petrochemical industry, raw rubber materials with different physical properties are synthesized according to different needs. Commonly used such as: SBR, NBR, EPDM, BR, IIR, CR, Q, FKM, etc. However, due to the difference in the synthesis method, the same type of rubber can be divided into several different raw rubbers, and through the setting of the formula, any type of rubber can be changed into thousands of raw rubbers that meet the needs of the product.

  2. The preparation of rubber raw materials

   The preparation of rubber raw materials can be divided into three basic processes:

  (1) Plasticizing: Plasticizing is to cut the raw rubber, and the raw rubber can be plasticized and homogenized to help the mixing operation of the compounding agent. The effect is to improve the dispersion of drugs, prevent frictional heat during operation, and cause scorching of the rubber, thereby changing the processability of the rubber.

  (2) Mixing: Mixing is to mix the compounding drugs into the finished raw rubber evenly, and the quality of the mixing directly affects the quality of the product. The drug is unevenly dispersed, the molecular structure cannot be completely cross-linked, and the rubber cannot achieve the desired physical properties.

  (3) Pressing out: After mixing the raw rubber, the excess air contained in the rubber compound is pressed out after pressing out, and the required thickness is completed to facilitate the molding operation in the mold.

  3. Rubber molding

  The molecular structure of raw rubber is an elastomer with unsaturated long bonds. Therefore, in the molding requirements, appropriate chemical additives and external environmental factors (such as time, temperature, pressure, etc.) are required to destroy the unsaturated bonds and then renew The combination is a saturated bond and is assisted by vacuum to completely force out the contained air. Only in this way can the molded rubber exert its proper characteristics. If there are any defects in the molding process (such as formula errors, insufficient time, inappropriate temperature, etc.), it can cause loss of physical properties, release of excess drugs, deformation, accelerated aging, and various serious adverse phenomena.

  4. The aging phenomenon of rubber

   According to the environmental conditions of the finished rubber product, over time, the phenomenon of cracking or hardening, and deterioration of rubber properties are called aging phenomena. The causes of aging include external factors and internal factors:

  (1) External factors: external factors include oxygen, oxides, ozone, heat, light, radiation, mechanical fatigue, lack of processing, etc.

  (2) Internal factors: internal factors include rubber types, molding methods, bonding degrees, types of drugs, factors in processing engineering, etc.

   The prevention of aging phenomenon focuses on the correct selection of rubber types and formula design, plus a rigorous production concept. Only in this way can the life span of rubber finished products be increased and their special functions can be exerted.

5. Basic characteristics of rubber products

  (1) When the rubber product is molded, the cohesive force provided by the elastomer cannot be eliminated after high pressure suppression, and it often produces extremely unstable shrinkage when it is molded out of the mold (the shrinkage rate of rubber varies depending on the type of rubber. ), it takes a period of time to be gentle and stable. Therefore, when a rubber product is designed at the beginning, regardless of the formula or the mold, it is necessary to carefully calculate the fit. If not, the product size is likely to be unstable and the product quality is low.

  (2) Rubber is a hot melt thermosetting elastomer, while plastic is hot melt and cold curing. Due to the different types of sulfide, the temperature range of the molding and curing of rubber is quite different, and it may even be affected by climate changes and indoor temperature and humidity. Therefore, the production conditions of rubber products need to be adjusted appropriately at any time. If not, the quality of the products may vary.