There are various types of silicone release agents with different properties and uses. How can release agent manufacturers choose release agents to achieve good results? Generally speaking, the material, structure, and shape of the mold, the type of product to be demolded, the operating temperature, post-processing properties (printability, adhesion), and diluents are all prerequisites that must be considered in die-casting and casting. First of all, the temperature of metal mold is the main source of selecting release agent. From the perspective of safety (fire and poisoning), solution type release agent cannot be used for hot mold, but lotion type, silicone paste type or silicone oil type release agent should be selected.
Silicone oil has no expansion or contraction effect on various rubbers and plastics, making it suitable as a release agent for them. However, silicone oil tends to migrate to the surface of the molded products to some extent, which affects their post-processing performance. For example, when molding epoxy resin, polyurethane resin, and polyurethane rubber, curing release agents are used or mixed with curing release agents. For molded products that require bonding, coating, and embossing, release agents formulated with dimethyl silicone oil cannot be used. If long-chain alkyl silane is used as a release agent, this drawback can be avoided. Any diluent, including organic solvents, propellants, and water, must not remain on the mold. Otherwise, it will lead to a decrease in product quality. Improper selection of diluent can result in uneven distribution of silicone oil on the surface of the mold, leading to stress cracking and accelerated aging of the product.
The application of silicone release agents in plastic molding processing has been used in the preparation of plastics, rubber, polymers, metals, glass, molds, and food through molding, pouring, and packaging methods. And silicone release agents are an important application target in the molding and processing of plastics. It is used in processes such as compression molding, transfer molding, injection molding, casting molding, and lamination molding of polyurethane, polystyrene, polyvinyl chloride, melamine, acrylic resin, epoxy resin, and polyester. Among them, the molding and demoulding of polyurethane foam plastics account for the majority. Usually, the solution or lotion type demoulding agent with a concentration of 0.5%~2.0% is used, which is sprayed on the clean mold and dried at the molding processing temperature for 30 minutes to obtain good demoulding performance.
