There are many kinds of silicone release agents, and the properties and uses are different. How to use the release agent to get the best results?
In general, the material, structure and shape of the mold, the type of the product to be released, the use temperature, the post-processability (printability, adhesion) and the diluent are all prerequisites. First, the mold temperature It is the main basis for the selection of the release agent. From the perspective of safety (ignition and poisoning), the hot mold cannot be used in solution type, but emulsion type, silicone paste type or silicone oil type release agent should be used. When using emulsion type release agent, Since the specific heat capacity of water is large, the evaporation rate is slow, and it is easy to leave moisture on the surface of the mold with insufficient heat, thereby affecting the uniform distribution of the release agent, so the water should be quickly distilled off when used. The cold mold cannot use the emulsion type, and the solution type and the oil type release agent are often used. The solution-type release agent is easy to wet and evenly distributed on the surface of the mold and the product, thereby obtaining a smooth product. However, when the organic solvent is naturally evaporated, it should be heated to further remove the solvent in the residual mold, so as not to affect the quality of the product.


In general, an inexpensive and safe emulsion type release agent is used for a mold having a simple structure and a high temperature. Since the demoulding of complex molds is difficult, it is advisable to increase the amount of release agent and use a high concentration of solution-type release agent, which is sprayed every time, and the cost is high. Therefore, it is better to use low-concentration products, but residual solvents. To be cleaned up. The release agent formulated with high-viscosity silicone oil has a slightly poor wettability, but the release effect is significantly better than that of the medium viscosity silicone oil. Oil-based and solvent-based release agents have less residual deposition on the surface of the mold than emulsion-type products, and solution-type and emulsion-type products prepared using high-viscosity silicone oil have better mold release durability. Silicone oil has no expansion and contraction effect on various rubbers and plastics, so it is especially suitable as a release agent, but silicone oils migrate more or less to the surface of the molded article, affecting their post-processing properties, for example, When molding epoxy resin urethane resin and urethane rubber, it is preferable to use a curing type release agent or to mix it with a curing type release agent. For moldings that require bonding, finishing, and embossing, mold release agents that cannot be formulated with dimethyl silicone oil can be dispensed with if long-chain alkyl (C8-C16) silane is used as the release agent.
Any diluent, including organic solvents, propellants, and water, must not remain on the mold. Otherwise it will lead to a decline in the quality of the product. Improper selection of thinner can cause uneven distribution of silicone oil on the surface of the mold, which leads to problems such as stress cracking and accelerated aging of the product.
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