3.4 One-component room temperature curing methylphenyl silicone resin
Most traditional methyl phenyl silicone resins need to be cured by heating or adding a drier to cure. This curing method brings inconvenience to certain specific uses, especially not suitable for large-area coating and applications where heating and curing are not allowed. The single-component methylphenyl silicone resin that can be cured at room temperature can simply solve the above-mentioned application process disadvantages. One-component methylphenyl silicone resin retains the excellent performance properties of traditional methylphenyl silicone resins, and at the same time has the advantages of no need for compounding and rapid curing at room temperature before the use of single-package products.
One-component, room temperature curing methylphenyl silicone resin is a branched organic silicon polymer with multiple hydrolyzable active groups. After this silicone resin solution is applied to the surface of a substrate, the polymer absorbs moisture from the air and is active. The reaction group is hydrolyzed and a cross-linking reaction of the polymer occurs until the coating film is cross-linked and cured.
In order to successfully produce room temperature fast-curing one-component methylphenyl silicone resin, the following technical keys must be solved: ① Ring or cage silicone inert oligomers must be excluded from synthetic silicone resin prepolymers to achieve finished silicone resins. The cured coating film will not stick back; ② It is also required that the silicon hydroxyl group in the silicone polymer has a sufficient subsequent condensation reaction activity, that is, the silicon hydroxyl group retained in the silicone prepolymer should correspond to the methyl substitution position Instead of the silyl hydroxyl group which should be at the phenyl substitution position, the subsequent condensation reaction is difficult to proceed smoothly due to the large steric hindrance of the phenyl group and the electronegativity; ③ a special process is required to avoid silicone resin prepolymers and crosslinkers The problem of gel curing of the reaction mixture may occur during the condensation reaction process; ④ choose a moderately active catalyst to ensure that the reaction to produce a highly active silicone resin proceeds smoothly, and the catalyst will not affect the storage stability of the silicone resin; ⑤ preferably stable The type and amount of the additives ensure stable storage of the silicone resin without affecting the rapid curing of the silicone resin at room temperature.
Economical and practical technical route for the rapid curing of methyl phenyl silicone resin at room temperature. It can start from methylchlorosilane and phenylchlorosilane and co-hydrolyze in the presence of organic solvents. The resulting silanol mixture is washed with water to remove acid, and then A nucleophilic catalyzed condensation reaction is prepared to obtain a silicone resin prepolymer having an appropriate amount of active silyl hydroxyl groups, and then a suitable cross-linking agent and a selective catalyst are added to further perform a catalytic condensation conversion reaction to obtain a methyl group having multiple hydrolyzable active groups Phenyl silicone branched polymer. Finally, a suitable amount of stabilizer and other auxiliaries are formulated, and the solid content is adjusted by adding or subtracting a solvent, so as to obtain a high-performance one-component methylphenyl silicone resin solution that can be rapidly cured at room temperature.
3.5 Silicone molding compound and foam
Make full use of the high insulation and high heat resistance of methylphenyl silicone resin, and add heat-resistant insulating fillers to the silicone resin to prepare silicone molding compounds, which can be used as heat-resistant insulating packaging materials or high-insulation moisture-proof protective materials for high-power electrical components. Considering the cost-effectiveness of silicone molding compound products, economically applicable silicone molding compounds should be based on medium, low R / Si and low Ph / R silicone resins as the base polymer, and quartz powder, chopped glass fiber, mica powder, etc. Used as filler, mixed with plastic, mixed with metal organic acid salt and other curing agents to prepare molding compound base material, and processing silicone molding compound products by transfer molding process.
Silicone molding compound is used for deep processing to prepare silicone foam, which replaces the expensive polyimide foam and is used for high temperature resistant insulation materials. Starting from cheap and easily available methylchlorosilane and phenylchlorosilane monomers, firstly, a low-medium R / Si solvent-free methylphenyl silicone resin was prepared by hydrolysis and condensation reaction, and chopped glass fibers and hollow glass microspheres were added. Lightweight fillers, combined with appropriate foaming agents and curing agents, are processed by transfer molding to achieve the simultaneous curing reaction of silicone resin and foaming of molding compounds to produce lightweight high-strength heat-resistant foams.
4 Application Prospects and Social Economic Benefits of High-Performance Silicone Resin Production Technology
Under the guidance of chemical theory, the high-performance silicone resin production technology developed through in-depth research and development has been tested in production practice. The high-performance silicone resin products obtained have achieved expected results in practical applications, including some high-performance silicone resins. It played an important role in supporting the defense industry.
High-performance silicone resin production technology opens up a new route for the synthesis of low-cost high-performance silicone resins. Compared with traditional silicone resin production technologies, the application of new technologies not only produces high-performance silicone resin products, but also significantly reduces energy consumption and reduces organic solvents. Emissions. Expanding the flexible use of these new technologies can also synthesize and improve many new types of high-performance silicone products.
Contact：Sharon Song(Sales manager)
Zhejiang Runhe Organosilicone New Material Co.,Ltd(Factory)
Zhejiang Runhe Chemical New Material Co.,Ltd(Exporter)
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