Overview of liquid silica gel
According to the position of functional groups (i.e. cross-linking points) contained in the molecular structure, liquid rubbers with functional groups are usually divided into two types: one is called telechelic liquid rubber with functional groups at both ends of the molecular structure; The other is that the active functional groups are randomly distributed in the main chain, that is, the molecular structure with functional groups is called non-telechelic liquid rubber. Of course, there are also intermediate functional groups and terminal groups. At present, the focus of research is remote claw liquid rubber. For liquid rubber, the chain extender or crosslinking agent with appropriate functional groups should be selected according to the active functional groups contained in it.
Liquid silicone rubber can be used for coating, dipping and pouring. Such as hydroxyl-terminated polymethylsiloxane with viscosity of 0.07~50 Pa/s /25℃, methyl vinyl bipyrrolidone silane as chain extender, and organic peroxide such as dibenzoyl peroxide and 25- dimethyl 5- di-tert-butyl peroxyhexane as vulcanizing agent. This kind of compound has good fluidity and low viscosity, and chain extension occurs at the same time during its vulcanization, so it can obtain high molecular weight elastomer with high molecular weight, high molecular weight and high viscosity. The chain extender methyl vinyl bipyrrolidone silane can be obtained by the reaction of pyrrolidone and methyl vinyl dichlorosilane in the presence of triethylamine. This product is easy to hydrolyze and needs to be stored in a dry and closed container. The pyrrolidone group of this compound can react slowly with the terminal hydroxyl group in polydimethylsiloxane at room temperature, and its reaction speed increases with the increase of temperature. Theoretically, the reaction can continue until an infinite molecular weight is obtained. The vinyl group in methyl vinyl pyrrolidone silane can also be used as the activation point of vulcanization reaction to promote the crosslinking of polydimethylsiloxane and generate high molecular weight elastomer. Because the reaction between pyrrolidone group and hydroxyl group is very slow at room temperature, the compound with mixed components has a long service life. The viscosity of the compound is basically unchanged within 65438 0 hours, but it still maintains good fluidity and can be injected into tiny pores. The rubber compound can be vulcanized into elastomer when heated at 65438 050℃ for 65438 00 minutes.
1. Injection molding liquid silicone rubber (LSR): the full name is injection molding liquid silicone rubber, and the vulcanization equipment is injection molding machine. Injection molding machine has many advantages, for example, the process is very simple (there are no manual processes such as batching, mixing, cutting and placing in the high-temperature glue process, only one worker needs to take the product), the product precision is high (all manual processes are replaced by machines before molding), the output is high (A/B glue is mixed for a few seconds at a certain temperature), which saves people, electricity and materials, and can produce all products produced by high-temperature glue! It is a mainstream in the development of silicone rubber materials in the next few years.
2. Mold silicone rubber: used for the molding of handicrafts and low-alloy molds. (RTV-2)
3. Electronic silicone rubber: used as a heat dissipation material for moisture-proof and insulating backlight boards and electrical components. (RTV-T)
4. sealant (RTV- 1): commonly known as glass glue, used for building sealing, waterproof engineering, aluminum bonding, electronics and lighting.
Use of liquid silica gel
Liquid silicone rubber can be used for trademarks, products, nipples, medical supplies, coating, dipping and pouring. Silica gel products such as crystal glue, polyurethane, epoxy resin, molding dies, injection molding processes, cake molds, etc. It is widely used as moisture-proof, leakage-proof, insulation coating and potting material for electronic components in the electronic industry, and plays a role in dust-proof, moisture-proof, earthquake-proof and insulation protection for electronic components and components. If the electronic components are encapsulated with transparent gel, it can not only play the role of shock prevention and waterproof protection, but also see the components, and use the probe to detect the faults of the components and replace them. Damaged silica gel can be encapsulated and repaired again. It can also be used to make molding dies for gypsum, wax, epoxy resin, polyester resin, polyurethane resin and low-melting alloy products, and can be used for high-frequency embossing of artificial leather, modeling of the top and bottom of shoes, manufacturing of handicrafts, ceramics, toy industry, copying of furniture, household appliances and electronic components, molding of gypsum and cement materials, molding of wax products, manufacturing of models, molding of materials, etc.
If necessary, please contact Serene Silicone. They focus on liquid silica gel 16 years, which is trustworthy!