The main difference between the two is the preparation of the parison, and then the blow molding process is essentially the same. On the basis of these two molding methods are: extrusion-stretching-blow molding (referred to as extrusion-pull-blowing), injection-stretching-blow molding (referred to as injection-pull-blowing) and multi-layer reflection Plastic and so on.
The injection-blow molding (referred to as injection-blow) plastic bottle is a hollow product which is formed by injection molding into a bottomed parison, and then the parison is heat-transferred into a blow mold. Note - The blown hollow container has no flash edge, good dimensional stability, excellent quality of the bottle mouth and thread, the thickness of the parison can be pre-conditioned, the gloss of the product is good, and the raw materials are saved. However, injection-blowing molding is not suitable for consuming large and complex containers, and equipment investment is large due to the use of two molds for injection and blow molding.
Note - The blown hollow container is mainly made up of a small-sized bottle of a single-piece shape, which can be consumed by various resins such as polyvinyl chloride, polyethylene, polypropylene, polystyrene, polyester, and polyamide. Mainly used in medicine, food, cosmetics, etc. The types of plastics used for hollow blow molding are polyethylene, polyvinyl chloride, polypropylene, polystyrene, linear polyester, polycarbonate, polyamide, cellulose acetate and Polyacetal resin, etc. Among them, the consumption of high-density polyethylene is the first. It is commonly used in the packaging of food, chemical and disposal liquids.