Recently, a new customer mentioned when consulting that the nitrile recycled rubber they use is not smooth when processed. If the surface of the processed nitrile recycled rubber material is not smooth, it will not only affect the appearance of the rubber product, but also lead to the reduction of the physical and mechanical properties and chemical stability of the product. So how to improve the surface smoothness of nitrile recycled rubber products?
1. Reasons that affect the surface smoothness of nitrile recycled rubber products
(1) The quality of nitrile recycled rubber
Nitrile recycled rubber is processed from waste nitrile rubber and its products as raw materials, if the raw materials are mixed with impurities, the inside of the nitrile recycled rubber contains impurities, which will cause the surface of the nitrile recycled rubber products to be not smooth.
(2) Improper operation of the mixing or vulcanization process
When nitrile recycled rubber is mixed, too high a mixing temperature or too long time will lead to the breakage of the rubber molecular chain, resulting in scorching phenomenon, too low temperature, insufficient mixing, will affect the surface smoothness of nitrile E5LYY85 recycled rubber products; If the vulcanization pressure of recycled rubber is insufficient or the time is too short, the rubber material is not fully vulcanized, and bubbles or pockmarks are prone to appear, resulting in uneven surface of nitrile recycled rubber products.
(3) The equipment or mold is worn or not clean
During the processing of nitrile recycled rubber products, the wear of the rollers of the opener or mixer, the uneven surface, the mold cavity is not cleaned or there are scratches, which will cause the surface of the product to be not smooth.
(4) The storage or production environment of nitrile recycled rubber and rubber compound is too humid, resulting in moisture residue during the vulcanization process of the rubber material, and the surface of the nitrile recycled rubber material will be unsmooth.
(5) Insufficient or excessive addition of softener will affect the fluidity of nitrile recycled adhesive, resulting in rough surface of the finished product.
2. How to improve the surface smoothness of nitrile recycled rubber products
(1) To improve the surface smoothness of nitrile recycled rubber products, it is recommended to choose high-quality nitrile recycled rubber with high nitrile content and high fineness, and for rubber products with strict requirements for surface smoothness, you can choose NBR recycled rubber with a fineness of 60-80 mesh.
(2) Reasonable parameters such as mixing temperature, mixing time, vulcanization temperature, vulcanization pressure and vulcanization time should be set during the processing of nitrile recycled rubber products; Avoid too high or too low temperature, too long or too short time, prevent scorching or insufficient mixing, ensure sufficient vulcanization of the compound, and improve the surface smoothness of nitrile recycled rubber products.
(3) Regularly maintain the production equipment of nitrile recycled rubber products, and inspect or replace worn rollers in time, clean the mold cavity, and repair scratches.
(4) Control the humidity of the storage and processing of nitrile recycled rubber to avoid moisture residue during the vulcanization process due to excessive humidity.
(5) Appropriately adjust the formula of nitrile recycled rubber products, including: (1) The amount of softener added to ensure that the fluidity of the rubber is moderate; (2) Avoid the use of large particles and impurities of rubber fillers, which can be matched with carbon black with high structure and low specific surface area, and talcum powder has a better effect on improving the surface brightness of nitrile recycled rubber products than calcium carbonate; (3) Use an appropriate amount of neoprene.
In actual production, the appropriate use of nitrile recycled rubber in nitrile rubber/PVC blended materials can not only reduce the cost of raw rubber, but also improve the problem of non-smooth film surface. I will share with you the specific application tips of nitrile recycled rubber in rubber products.
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