What is the basic principle of PE chemical foaming?
Publish Time: 2025-02-05
PE (polyethylene) chemical foaming is an important plastic processing technology. Its basic principle involves the combination of chemical reactions and physical changes, aiming to manufacture foamed materials with lightweight, heat-insulating, cushioning and other properties. The following is a detailed explanation of the basic principle of PE chemical foaming.
The core of PE chemical foaming is the use of chemical foaming agents. These foaming agents usually exist in PE resin in the form of solid particles. During the heating process, the foaming agent will undergo a decomposition reaction to produce a large amount of gas (such as nitrogen, carbon dioxide, etc.). These gases form bubble nuclei inside the PE resin. With the continuous action of heating and pressure, the bubble nuclei gradually expand to form a uniformly distributed bubble structure.
Specifically, the PE chemical foaming process includes the following key steps:
Raw material preparation: PE resin, chemical foaming agent and other necessary additives (such as cross-linking agent, stabilizer, etc.) are mixed evenly in a certain proportion.
Heating and melting: The mixed material is fed into an extruder or injection molding machine and melted by heating. During this process, the chemical foaming agent begins to decompose and produce gas.
Bubble formation and expansion: As the temperature rises and gas is generated, the pressure inside the PE resin gradually increases. When the pressure exceeds the yield strength of the resin, bubbles begin to form and expand. This process requires precise control of the heating temperature and time to ensure the uniform distribution and expansion of the bubbles.
Cooling and curing: After the bubbles expand to a certain extent, the foaming material is quickly cooled and cured. This process helps to stabilize the bubble structure and prevent gas escape and cell collapse.
The advantage of pe chemical foaming is that it can produce foaming materials with excellent thermal insulation, light weight and good cushioning properties. These materials are widely used in packaging materials, building insulation, automotive interiors, electronic products and other fields. In addition, by adjusting parameters such as the type and amount of foaming agent, the molecular weight of PE resin and the degree of cross-linking, the performance of the foaming material can be further optimized to meet the needs of different fields.
In short, the basic principle of pe chemical foaming is to use chemical foaming agents to decompose and produce gas during heating, thereby forming a bubble structure inside the PE resin. This process requires precise control of various process parameters to ensure the performance and quality of the foaming material.
