Silicone release agent production and application technology

Rubber and plastic products are formed and processed in the mold. The rubber and plastic materials are in contact with the surface of the mold. There may be a certain amount of friction when the rubber and plastic products are peeled off from the mold due to micro-defects such as unevenness on the working surface of the mold. resistance. During the injection or extrusion process of rubber plastics, negative pressure often forms between the rubber and plastic materials and the mold, or the two become bonded due to physical adsorption or chemical bonding, resulting in the rubber and plastic products falling out of the mold after molding. Difficulty in stripping. In order to weaken the adsorption or knot between the product and the mold, an additive that can form an effective isolation film—a release agent—is often used. Release agent is an interface film layer used on the surfaces of two objects that are easy to separate from each other to form an isolation between the bonded object and the object to be separated, making it easy to peel off and making the product easier and more convenient to demould.

1. Overview of release agent types and applications

Generalized release agents include many types, which are used in chemical industry, metallurgy, building materials and other fields. This article is limited to release agents in the chemical industry, and mainly discusses the external aspects of the molding and processing of rubber, plastics and other materials.

Release agent.

There are many basic substances that can be used as release agents. Commonly used release agents include inorganic substances, organic substances and polymers. Commonly used inorganic release agents include graphite powder, talc powder, mica powder, molybdenum disulfide and other powders; commonly used organic release agents include fatty acids, fatty acid soaps, various waxes, ethylene glycol, etc. Release agents also function as lubricants; polymer release agents mainly include polyvinyl alcohol, cellulose acetate, organic fluoropolymers and silicone polymers, among which silicone polymers are the most suitable release agents.

Mold release agents are available in two types: solid and liquid. The solid form uses fine powdery materials. Because powdery materials are inconvenient to apply and may transfer to the surface of rubber and plastic products, they are rarely used in the processing of rubber and plastic products. Frequently used mold releaseheight: 1em; text-align: justify;”>(4) High temperature resistant non-migration silicone release agent for aerospace engineering

High-performance fiber composite materials used in aerospace engineering require high molding and processing temperatures, and the molded products are required to maintain reliable knot performance. The requirements for release agents for the molding and processing of such composite materials are extremely stringent: in addition to requiring high molding accuracy and low product release force, the release agent is also required to have a working temperature of over 180°C, and even individual workpieces are required to be processed at temperatures as high as 4000C, it is also required that the release agent components must not migrate to the parts to avoid affecting subsequent knotting processing. The author uses special composite silicone resin as the base polymer, combined with high-temperature resistant wetting agents and composite solvents, to produce a release agent that fully meets the above demanding requirements. This release agent has good coating and leveling properties. After the coating film is heated and cured at 150°C, it can be used repeatedly and continues to maintain reliable release performance of high temperature resistance and non-migration. Due to its high efficacy and high reliability, this release agent is widely used in the processing of various aerospace engineering composite materials.

(5) High-efficiency dip-coating anti-corrosion isolating agent

When electronic components are impregnated and encapsulated with liquid resins such as epoxy resin, they often encounter the problem that the metal leads attached to the encapsulating liquid resin are difficult to remove. If mechanical scraping is used, it is not only inefficient, but also affects the solderability of the components by scratching the coating on the leads. If a commonly used release agent is used to pre-coat metal leads, the migration of the release agent often causes the impregnated packaging resin to be short of material at the root of the lead and the components cannot be marked after encapsulation. The author used low surface energy silicone polymer and high cross-linking degree curing agent components to develop a high-efficiency dip-coating anti-crack release agent. Apply the isolating agent to the appropriate parts of the metal leads of the electronic components. After curing, the electronic components are immersed in the liquid epoxy resin beyond the lead parts pre-coated with the isolating agent. When the electronic components are lifted out of the material bath, they are originally attached to the The epoxy resin in the lead part of the pre-coated isolator will automatically shrink upward against the direction of gravity, so that the electronic components are tightly and fully packaged and the leads are completely free of resin. The produced electronic components maintain reliable solderability.