PVC sealing strip
DATE：2022/11/15 8:40:22 / READ： / SOURCE：This station
PVC sealing strip
Plastic sealing strip is a strip product with multiple shapes in cross section. It uses the elasticity of the sealing strip and the contact pressure generated by the joint to seal the contact part. This article only introduces the forming method of oil resistant PVC sealing strip.Oil resistant PVC sealing strip is mainly used for sealing the joint of automobile and mechanical parts, belonging to static sealing occasions.
(1) Raw materials for oil resistant sealing strip extrusion molding are SG2 resin in suspension PVC and nitrile rubber blend as the main raw materials, and then a certain proportion of plasticizer, stabilizer and other auxiliary materials are added to form the PVC sealing strip extrusion molding material formula. For example, the reference formula (mass fraction): polyvinyl chloride (PVCSG2) 70, nitrile rubber (NBR-26) 30, carbon black 15, dioctyl phthalate (DOP) 45, calcium stearate (CaSt) 0.55, antioxidant 264 (BHT) 0.5.
(2) Forming process
① Nitrile rubber block shall be cut into pieces first, and then the plastic shall be smelted in the open mill. After the plasticization is uniform, carbon black shall be added, and then the rubber shall be mixed until the mixing and plasticization are uniform, and then the rubber can be sliced and rolled in the lower roll.
② The PVC resin, stabilizer and other auxiliary materials shall be measured according to the formula requirements, added into the high-speed mixer, and the raw materials shall be mixed evenly. After mixing, the material temperature shall be controlled at about 125 ℃.
③ Put evenly mixed PVC resin material into the open mill, and mix the PVC resin material into sheets at the roller temperature of about 170 ℃; Then add the black rubber sheet into the upper roll after mixing, mix it with PVC resin material, and continue to refine until the two materials are mixed and plasticized evenly, cut into long sheets with a certain width, and the lower roll is cooled and rolled.
④ Granulate the mixture sheet with a granulator.
⑤ The granules are put into the general single screw extruder for extruding PVC materials for plasticization, and the products are extruded by the profiled material molding die with the required section shape of the sealing strip. After cooling and shaping, the PVC sealing strip is formed.
The plasticizing temperature of the raw materials in the barrel of the extruder is slightly lower than that of the extruded PVC material when the PVC resin and nitrile rubber blend are extruded to form the sealing strip. The molding material temperature is generally controlled within the range of 120~130 ℃. The temperature control shall be determined according to the actual production conditions such as the material formula, screw structure and working speed.
Author：admin