There are many different methods used to improve mold fouling in the synthesis of elastomer rubbers. These techniques include internal release mold release agents, external release agent sprays, mold surface treatments, and appropriate process parameters. A more effective approach is to combine these methods.
Importantly, all elastomer mixtures in the mold should contain at least one internal release mold release agent. These internal release agents are typically waxes, fatty acids, phosphoric acids, or other low-molecular-weight compounds that migrate to the surface during molding and form a protective film on the mold surface. While effective, adding too much internal release agent can lead to agent buildup on the mold surface, forming fouling.
External release agent sprays function similarly to internal release agents, but they are sprayed directly onto the mold surface before the part is molded. They can also lead to mold fouling if sprayed too much. External release agent sprays can be semi-fixed, reducing the frequency of spraying and the potential for excessive buildup. Today, most are water-based agents, primarily silicone- or fluorine-based.
Mold surface treatment methods help protect materials from wear during processing, providing corrosion protection through various chemical reagents and byproducts, preventing chemical erosion, and giving parts a smooth, non-porous surface, reducing mold contamination. Chromium-nickel gold plating is widely used. Teflon, silicon carbide, and industrial-grade nickel-diamond plating can significantly extend service life. Furthermore, new demolding structure designs are constantly emerging, such as multi-stage ejection (first overall, then internal) structures, which effectively avoid deformation, cracking, or damage caused by uneven force during a single ejection, significantly improving the product yield.
