Processing and production methods of plastic bottle caps

Update:17 Jan 2022

Plastic bottles have certain processing and production methods. The processing methods mainly include extrusion, injection molding, calendering, blow molding, molding, lamination, casting and many other methods. The plastic bottle is processed by blow molding, that is, the plastic is heated and melted and then pressed into a special blow molding mold. At the same time, there is a high pressure of air inside to press the plastic onto the mold to form the final product shape. Because the bottle is forming When it is subjected to outward pressure, the internal stress of the bottle itself is inward. After the heating temperature reaches a certain level, the plastic will soften, and the resistance to the internal stress will become smaller, so the bottle will become smaller.
Plastic bottles have certain processing characteristics in processing and production, and are processed in a certain way to benefit processing methods to ensure good quality and performance in production and processing. The following introduces the processing characteristics of plastic bottles in different aspects:

The shrinkage rate of reinforced plastics is smaller than that of general compressed plastics, and it is mainly composed of thermal shrinkage and chemical structure shrinkage. The first factor that affects shrinkage is the type of plastic. Generally, novolac is larger than epoxy, epoxy novolac, unsaturated polyester, etc., among which the shrinkage of unsaturated polyester material is small. Other factors that affect the shrinkage are the shape and wall thickness of the plastic part, the thick wall shrinks greatly, the filler and glass fiber content in the plastic is large, the shrinkage is small, the volatile content is large, the shrinkage is also large, the molding pressure is large, and the loading volume is large. The shrinkage is small, the shrinkage of hot demolding is larger than that of cold demoulding, and the shrinkage of insufficient curing is large. The shrinkage rate of plastic bottles is one of the important factors affecting the use of plastic bottles. In use, the shrinkage rate of plastic bottles should be reduced to prevent important shrinkage during use and affect the actual use effect.
The fluidity of the reinforcing material is worse than that of the general pressed plastic, and when the fluidity is too large, it is easy to produce resin loss and the accumulation of glass fiber split ends. If it is too small, the molding pressure and temperature will be significantly increased. There are many factors that affect the fluidity. To evaluate the fluidity of a certain material, a specific analysis must be made according to the composition. Factors Affecting Liquidity.