The release agent is a substance that separates the product from the mold and attaches to the molding surface of the mold. In the case of repeated use of the mold, the thickness, hardness, cavity size and mold acceptance test the gel coat layer the most. At the same time, a proper thickness of the gel coat layer can prevent the backside fibers from revealing, but if the gel coat layer is too thick, the surface layer will be too brittle and affect the service life of the mold. It is used to evaluate the degree of curing of the gel coat layer to ensure that the product size meets the requirements.
After spraying the release agent on the mold surface, the contact surface between the vulcanized molding compound and the release agent is side A, the release agent side is side B, and the contact surface between the release agent and the mold is side C; the release agent layer is agglomerated Floor. When demolding, it is called interface peeling when peeling on the A side and C side, and it is called coacervate failure when peeling off on the B side
1. Due to the orientation of the polar groups of the lubricant molecules on the metal surface, a static lubricant mold layer is formed due to adsorption
2. The silicon-oxygen bond in polysiloxane can be regarded as a weak dipole (Si+-O-). When the release agent is spread on the mold surface into a single-molecular orientation arrangement, the molecules adopt a unique extended chain configuration.
3. Since the surface is covered by alkyl groups in a densely packed manner, the demolding ability increases with the density of the alkyl groups; but when the alkane occupies a large steric hindrance, the stretching configuration is limited and the demolding ability will be reduced.
The molecular weight and viscosity of the release agent are also related to the release ability. The molecular weight is small and the spreadability is good, but the heat resistance is poor. Classification is classified by usage: internal release agent and external release agent; release agent is mainly used for external release agent for hand lay-up. Commonly used external release agents are divided into three categories: film release agents, liquid release agents and wax release agents. External release agents are mainly used in hand lay-up and cold curing systems (such as winding molding, etc.).