An Overview of Hollow Blow Molding（A）

Abstract: Hollow blow molding is a rapidly developing plastic processing method primarily utilized in the manufacturing of hollow plastic products. This paper introduces the basic principles, materials used, process control, applications, and current market trends of hollow blow molding. Additionally, it discusses the advantages and disadvantages of this technique and explores its future development directions.

Keywords: Hollow blow molding; Plastic processing; Molding materials; Process control; Market trends

1. Introduction

Hollow blow molding, also known as blow molding, is a molding method used to produce hollow plastic products. It involves inflating a molten parison (tubular preform) with compressed air to fit snugly against the mold cavity, which is then cooled to obtain the final product. This method is widely applied in various industries due to its high production efficiency and cost-effectiveness.

2. Basic Principles

The basic principle of hollow blow molding involves inserting a molten parison into a mold of a specific shape and inflating it with compressed air to expand and fit tightly against the mold cavity. The parison is formed by extruding or injection molding thermoplastic resin. After closing the mold, compressed air is immediately introduced into the parison, causing it to expand and adhere to the inner wall of the mold. The molded product is then cooled and ejected from the mold.

3. Materials Used

A variety of plastics can be used for hollow blow molding, including polyethylene (PE), polyvinyl chloride (PVC), polypropylene (PP), polystyrene (PS), linear polyester, polycarbonate (PC), polyamide, cellulose acetate, and polyacetal resin. Among them, PE consumption is the highest, particularly in food, chemical, and liquid packaging. PVC, due to its good transparency and gas tightness, is commonly used in packaging for cosmetics and detergents.