For those who don't understand the concept of mold release agent, Xiao Bian often takes fried eggs as an example. Without adding cooking oil, the eggs will stick together with the iron pot when they are heated and solidified, and they can be brushed with a layer of oil before the hot pot. It will be a miraculous effect, and this edible oil can be understood as a release agent, which is used to isolate the iron pan and the egg, so that the egg is easily separated from the iron pan after being solidified.
However, the release agent for industrial use is not as simple as frying eggs. The ideal release agent product, whose main function is to prevent or reduce the mechanical damage of the molded product when it is molded, should also have:
1 release effect is good;
2 no corrosion to the mold, no deposition;
3 easy to spread (spreading), leaving no blanks;
4 the surface of the product is smooth;
5 does not affect the post-processing of products (such as bonding, printing, finishing, embossing, etc.)
6 dilution is stable;
7 thinner is physiologically inert, non-flammable, and volatile;
8 low cost, low dosage;
9 one coat can be used multiple times;
Silicone oil has the characteristics of small surface tension, good heat resistance and low solubility parameters. It is an ideal release agent material and has long been used as a release agent. Compared with commonly used organic release agents (such as wax and stearic acid), it has many advantages, such as easy to flow to the surface of the fine structure of the mold to form a film; the amount is small, the brush can be used multiple times, A variety of materials are easy to demould, non-contaminated moldings and molds, high surface precision; no need to clean the mold often, reduce operating procedures and time; good resistance to most polymer materials and lubricity; no corrosion Mold and products; high flash point, non-toxic and tasteless, safe to use; physiologically inert, some products can be used as food packaging materials and mold release agents for food baking.
   Silicone oil release agents can be applied in processes such as molding, casting, packaging, and coating. Currently used in the molding of plastics including thermoplastics and thermosets, rubber (including synthetic and natural rubber) processing, precision casting, cast glass products, printing and packaging, especially in tire molding and polyurethane plastics production. Used the most. Although the production cost of the silicone oil release agent is higher than that of the general mold release agent, it can be compensated for because it is used in a small amount. In addition, it does not produce smoke and odor when used, and is more popular for users.
   A silicone-based semi-permanent release agent that reduces coating frequency and surface treatment time, thereby reducing the time required to clean the mold or mold. High-viscosity silicone oil is used as an internal processing aid and a release agent in the thermoplastic resin, which helps to shorten the production cycle, reduce the scrap rate, wear of tools and equipment, and facilitate demolding. However, this use has now been increasingly replaced by cross-linked siloxanes. Since the release agent using dimethyl silicone oil as the base oil is often difficult to print, coat and bond due to the migration of the silicone oil to the product. Therefore, an extractable release agent using methylphenyl silicone oil and long-chain alkyl silicone oil as a base oil was developed. At the same time, a fluorocarbon-based silicone oil release agent has also been developed.
The base polymer suitable for use as a silicone release agent, mainly non-crosslinking type silicone oil and crosslinkable type silicone rubber or silicone resin, which can be directly used as a mold release agent, or can be formulated into an organic solvent, A white carbon black thickener or emulsifier and water, etc., are correspondingly prepared into a solution type, an aerosol type, a silicone paste type or an emulsion type release agent product. Accordingly, the silicone release agent can be classified into pure silicone oil type, solution type, silicone paste type, emulsion type, spray type and curable type according to the product form.
   The above six products may be used singly or in combination or in combination with an organic release agent. According to the service life, during the working process of the release agent, the component of the release agent is partially transferred to the product, that is, the release agent is gradually consumed in the process of molding the plastic product, and the release agent is called temporary type. A release agent, or a migration release agent. A silicone release agent based on various inert silicone oils is a migration release agent. The temporary release agent is applied once or once for a limited number of times. If the film layer after the release agent is solidly adhered to the surface of the mold, the mold release agent component is not transferred to the product during the processing and molding process of the product, and the mold release agent is not consumed, and the release agent is called Semi-permanent release agent, or non-migratory release agent. A silicone release agent based on a crosslinkable and curable silicone resin is a non-migratory release agent. The release agent component will not be transferred to the plastic product, and will not affect the subsequent processing such as bonding and coating of the molded plastic product.