Organic silicon paint modified by organic resin

Organic silicon paint modified by organic resin      In order to overcome the poor adhesion of silicone impregnated, low mechanical strength, high solubility difference and the disadvantage of high cost, availability of organic resin modified. There are two kinds of production method of modified silicone resin, one kind is direct mixing method, the silicone resin and other organic resin are mixed according to a certain proportion; another is copolycondensation by initial polycondensation of poly silicone resin and other organic resin interaction, in order to achieve chemical synthesis is a new type of silicone resin.     For organic resin mixed with urea, melamine, epoxy resin, alkyd resin, phenolic resin, polyester resin, poly methyl acrylate. In most cases, because of the silicone resin and organic resin is not soluble, therefore, the silicone resin and organic resin using physical methods together to achieve good results in not. In most cases, is the use of two components for chemical reaction ( including polymerization, condensation and addition reaction ) method. By chemical modification, so that the copolymer has good properties of silicone resin and organic resin, improve the drying conditions of silicone resin, shorten the drying time, improve the compatibility performance of hardness, adhesive film force, solvent resistance and paint box organic resin, which is better than pure silicone resin. Organic resin modified with silicone paint, compared with pure silicone paint, its thermal stability, weatherability, water resistance and other organic material incompatibility ( manifested as demoulding effect ) are improved, but also reduce the cost.      At present, for the organic modified resin are: polyester resin, epoxy resin, phenolic resin, alkyd resin and polyurethane, polycarbonate, poly vinyl acetate, acrylic acid, which is the most used polyester and epoxy resin. Now for most foreign silicone high-temperature coil is copolymer polyester modified.      Epoxy modified silicone paint is CH3SiCl3, (CH3 ) 2SiCl2 and C6H5SiCl3 were hydrolyzed in the presence of ethanol, hydrolysis products remain a part of ethoxylated; then two phenyl propane epoxy resin with low molecular weight and polysiloxane containing hydroxyl, ethoxy is condensed prepared. Shanghai resin factory production of 665 organosilicon epoxy resin as an example, its performance is as follows: Appearance: light yellow to yellow uniform liquid, allowing a milk white, without visible particles. Solid content: >50% Viscosity ( TU -4 cup, 25 ℃):≤30 seconds Epoxy value ( equivalent /100 g ): 0.01 to 0.03 Drying time: less than 4 hours at /140 ℃ Heat ( 200 ℃, 3mm ): 168 hours without cracking Thermal weight loss ( %): 4.15/250 ℃, 10 hours. The electrical breakdown strength ( normal): 103000 V / mm The volume resistance ( normal): 2.95 * 10 ^ 16 ohm / cm Adhesion: 21.7 kg /cm² ( Note: the above performance indexes by using KH-550 as curing agent ) Curable silicone paint modified by epoxy resin curing agent must be added. The curing agent is mainly amine compounds, 665 epoxy modified silicone paint mainly through three kinds of reactions to achieve cure: Epoxy group on the nitrogen atom of hydrogen and the 1 resin, amine compounds produced in addition polymerization, to generate three-phase network structure of polymers. This is the most important reaction. 2, amine compounds with alkaline, it may cause resin cohesive silicone residue dehydration reaction between hydroxyl and the formation of cross-linked at above 100 ℃. 3, resin containing naphthalene acid zinc, it plays in the high temperature activation effect of residual hydroxyl polysiloxane, cause dehydration reaction between hydroxyl groups, plays an increasing crosslinking density function. Epoxy modified silicone paint can be used for impregnating varnish H machinery, electrical appliances and transformer coil, high temperature resistant, moisture-proof coating of water, can also be used for laminate.