Glossary: What is "gas" in injection molding?

　　　　　　　　　　　(Resin purging White smoke is gas generated from resin)

Gases generated from resin are volatile components and decomposition products contained in the resin that vaporize or gasify under high temperatures. During the injection molding process, as the resin is heated and melted, some of the volatile components, additives, and molecular structures within the resin may be released as gases.

The main sources of gases emitted from resins are as follows

Resin volatile components: Resin materials may contain volatile components such as plasticizers, solvents, demolding agents, and stabilizers added by the manufacturing process or raw materials. During the injection molding process, these components can vaporize at high temperatures and be released as gases.

Decomposition Products: Resins can decompose under conditions of high temperature and pressure. The gases produced by degradation reactions depend on the chemical composition of the resin and the process conditions. For example, gases produced by polymer degradation include carbon dioxide, carbon monoxide, methane, and volatile organic compounds.

These gases can form bubbles or pores inside or on the surface of the molded product during injection molding. Since gas generation affects the appearance and physical properties of molded products, it is important to optimize design and process control. Gas generation must be minimized through material selection, optimization of additives, and control of process conditions.

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