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Silicone oil in mold release agent
The silicone oil release agent is a secondary processing product of silicone oil prepared by using silicone oil as a base oil, a dispersing component and various auxiliary agents, and is in the form of oil type, emulsion type, solvent type, grease type, aerosol type and the like. Widely used in rubber, plastic and shell casting industries. Compared with other types of release agents, silicone oil release agent has the following characteristics: small surface tension, easy spreading, and extremely thin film can be formed in the fine parts of the mold; it is incompatible with most polymer materials, and is released. Excellent in properties; good heat resistance and chemical stability, no chemical reaction to the material being contacted, no corrosion of the mold. It does not produce smoke and odor when used; it has no pollution to the surface of the molded product and can impart luster; the coating amount is small, the mold release durability is good; and there is no physiological activity.
1. The silicone oil used in the oil type release agent has the following types:
1. Dimethyl silicone oil: widely used in rubber, plastic processing and fine casting industries. The release anti-stickiness increases with the increase of the molar mass of the silicone oil, while the low molar mass of the silicone oil has good spreadability and surface affinity; therefore, when used directly, the viscosity can be selected to have both properties (25 ° C). 100-30000CP of dimethicone is diluted with a solvent to a volume fraction of 0.2% to 2%. For rubber products with relatively low forming temperature, dimethyl silicone oil with viscosity (25 ° C) of 100-1000 CP can be used. For fine casting with high forming temperature and multi-material materials such as gypsum, paper products, etc., it should be higher than 1000CP. Dimethicone. The dilution solvent should be selected according to the model treatment temperature. The low temperature solvent such as toluene, xylene, industrial gasoline or trichloroethylene can be selected at a temperature of about 100 °C. For high-temperature applications such as fine casting, high-boiling solvents such as mineral turpentine can be used.
2, hydrazine-based silicone oil: 巯 propyl mole fraction of 0.05-0.4%, viscosity (25 ° C) 100-10000CP 巯 propyl silicone oil has higher heat resistance and lower surface tension than dimethyl silicone oil, there are It has high mold release property and anti-oxidation and anti-corrosion function on metal surface. It is suitable for mold release agent for forming silicone rubber, fluorine rubber and various engineering plastics.
3. Amino-modified silicone oil: It is a kind of release agent for polyurethane and other high-adhesive plastics and rubber products. It can be used alone or in combination with dimethyl silicone oil or MQ-type silicone resin to improve the release durability.
4. Long-chain alkyl silicone oil and α-methylstyryl-modified silicone oil: Both are the basic components of the coatable silicone oil release agent. Because they have good extreme pressure lubricity, they can be used as a release agent for metal die for die cutting.
5. Polyether modified silicone oil: As a release agent, it has easy coating, solvent-free environment and safety problems. The release agent on the surface of the shaped product can be washed off with water to facilitate further surface processing. It can be used for the forming of rubber and plastic materials such as polyurethane foam.
Second, solution type release agent
The solution type release agent is prepared by dissolving or dispersing the silicone oil and the additive in an organic solvent, and generally contains 5-50% of the active ingredient. According to the type of silicone oil used, viscosity and additives, it is divided into several series. Mainly used for shell mold casting, die casting, rubber and plastic products.
The solution type silicone oil release agent is mainly composed of various silicone oils, and other additives for improving mold release such as various waxes, mica powder, talc powder, clay, MQ type silicone resin and polymethylsilsesquioxane may be added. Micro powder and so on.
1. Adding polyethylene wax and stearate to dimethyl silicone oil, and using a paraffin wax with a melting point of -5 ° C and a boiling point of 120 ° C as a solvent to improve the adhesion of polyurethane foam Modularity and surface state of the shaped article.
2. The solution release agent prepared by mixing organic solvent with dimethyl silicone oil and MQ type silicone resin has a very good effect on improving mold release durability. If silicone oil and MQ silicone resin are mixed at 80:20, the prepared release agent is diluted with solvent, and the surface of the mold can be applied once to ABS, PPS, PA6, PBT, PC, POM and other thermoplastic resins and ethylene propylene rubber. The nitrile rubber, the acrylate rubber and the like are continuously released from the mold for 7-11 times, and the dimethyl silicone oil solution without the MQ type silicone resin can be released only 2-3 times.
3. A solution type silicone oil release agent formulated with dimethyl silicone oil or methylphenyl silicone oil and polymethylsilsesquioxane spherical fine powder can improve mold release durability and improve silicone oil migration.
4. A mold release agent prepared from industrial gasoline such as mica powder or clay is added to the silicone oil for demoulding between the inner side of the carcass and the elastic one in the tire vulcanization process, which can increase the isolation effect and the fluidity under extrusion. The elastic bladder can be easily peeled off from the inside of the tire to extend the service life of the bladder.
Third, emulsion type silicone oil release agent
1. The general emulsion type release agent is prepared by phase inversion emulsification method of dimethyl silicone oil and surfactant in water by high-speed agitator, colloid mill, homogenizing pump and the like.
2. The emulsion type silicone oil release agent prepared by mixing the dimethyl silicone oil with the MQ type silicone resin and the anionic surfactant in the phase emulsification method in water, and the external mold release agent for the polyurethane forming can be formed on the frame. The hard, high melting point film has very good release durability, and the mold release property does not decrease at a high temperature of 50 ° C or higher.
3. The active ingredient in the coatable emulsion type silicone oil release agent is a long-chain alkyl-modified silicone oil or an α-methylstyryl-modified silicone oil.
4. An emulsion type silicone oil release agent prepared by emulsion polymerization of a dimethylcyclosiloxane oligomer.
4. Ointment type silicone oil release agent is a paste release agent prepared by mixing gas phase white carbon black or precipitated white carbon black into silicone oil, and has higher resistance than oil type, solvent type and emulsion type silicone oil release agent. Heat and release durability. Suitable for high temperature and high pressure forming; and, due to its lubricity at the same time, it is especially suitable for vulcanization of curved rubber hoses. It can also be used as a release agent for the spinning orifice of the synthetic spinning process of polyester, nylon and the like.
5. Aerosol type silicone oil release agent is made of dimethyl silicone oil, methyl phenyl silicone oil or long-chain alkyl silicone oil as active ingredient, and the mixture of Freon-11, Freon-22 or Freon substitute is used as a propellant. Formulation in an aerosol can.