Performance of Polyester Modified Silicone Paint
Jul 10, 2024
Compared with pure organic silicone paint, silicone paint modified with organic resin has improved thermal stability, weather resistance, waterproofing, and incompatibility with other organic materials (manifested as demolding effect), and also reduced costs.
At present, the main organic resins used for modification include polyester resin, epoxy resin, phenolic ester resin, alkyd resin and polyurethane resin, polycarbonate, polyester ethylene, acrylic acid, etc. The most commonly used modified silicone resins are polyester and epoxy resin as organic silicon coil impregnation paint, which can improve the adhesion and mechanical strength of pure organic silicon coil insulation paint to the substrate, but the heat resistance is reduced (about 150 ° C), and can generally only be used as F-grade insulation material.
Special polyester and epoxy modified silicone resin have excellent electrical insulation properties, with a volume resistivity of 1016 n. cm and a dielectric strength of 90kV/mm. Good heat resistance. The curing temperature is lower than 050 ° C/3h. Good impregnation dryness, uniform and dense paint film, and good moisture resistance. It can be prepared by condensation reaction between silanes or siloxanes containing tibia or alkoxy groups and low molecular weight polyester resins containing light groups in the presence of lead acetate catalyst. Used as impregnating paint for H-class motor electrical equipment and transformer coils. Currently, most of the silicone resins used on high-temperature coils abroad are copolymers modified with polyester.
Polyester modified silicone paint involves first hydrolyzing dimethyldichlorosilane and phenyltrichlorosilane in the presence of xylene and n-butanol solvents to produce silanol, followed by ester exchange and condensation reactions of dimethyl terephthalate, trilight methylpropane, and ethylene glycol in the presence of zinc acetate catalyst to produce multi tibia based polyester. Then, the silanol is co condensed with the polyester to obtain it. In silicone resin, R: Si=1.44~1.5, and the phenyl content Ph/(Ph+Me) ranges from 33% to 40%.
Polyester modified silicone paint not only has high heat resistance (080-190 ° C) and good insulation properties, but also has characteristics such as low curing temperature, good dryness, and fewer bubbles during impregnation. It is suitable for impregnating H-class motors, electrical appliances, and transformer coils.
Epoxy resin modified silicone paint is co hydrolyzed with CH3SiC'3, (CH3) 2SiCl2, and c6 pressured SiCb in the presence of ethanol, and a portion of the ethoxy group is retained in the hydrolysis product; Then, low molecular weight bisphenol propylene type epoxy resin is condensed with polysiloxane containing tibia and ethoxy groups to obtain. Taking 665 organosilicon epoxy resin as an example, its properties are as follows.
Appearance: Light yellow to yellow uniform liquid, allowing milky white light, no visible particles, solid content:>50%
Viscosity [4 cups coated, (25 soil l) ° CJ:, s;; 3os epoxy value (equivalent/100g): 0 01~O. 03 Drying time:, s;; 4h/140 ° C
Heat resistance (200 ° C,'P3mm): No cracking after 168 hours
Thermal weight loss (%): 4.15/250 ° C, lOh
Breakdown strength (normal): 103kV/mm
Volume resistance (normal): 2 95Xl016.Q• cm
Bonding force: 217kgf/mm2
The curing agent (mainly amine compounds) must be added during the curing of epoxy resin modified silicone paint. The commonly used types, amounts, and characteristics of curing agents can be roughly summarized as follows:
Epoxy modified silicone paint mainly achieves curing through the following three reactions.
The active hydrogen on the nitrogen atom in CD amine compounds and the epoxy group on the resin undergo an addition polymerization reaction, resulting in a three-dimensional network structure of polymers. This is the most important reaction.
Amine compounds have alkalinity and can cause dehydration reactions between residual residues on the resin at temperatures above 100 ° C, resulting in cross-linking.
The resin contains zinc titanate, which plays a role in activating the residual tibia groups on the polysiloxane at high temperatures, causing dehydration reactions between the groups and improving the crosslinking density.
Epoxy resin modified organosilicon paint can be used as impregnating paint for H-class motors, electrical appliances, and transformer coils, as well as moisture-proof coatings that are resistant to high temperatures and seawater. It can also be used for lamination.
Compared with pure silicone paint, silicone paint with added organic resin may have drawbacks such as discoloration and loss of gloss during heating. However, if only focusing on the adhesion of a thousand pairs of substrates, the adhesion of modified silicone resin paint is significantly improved.
Our main products are Methyl MQ Silicone Resin Powder,MQ Methyl Silicone Resin Liquid,MQ Silicone Resin,MQ Silicone Resin Powder,Liquid MQ Silicone Resin,Vinyl MQ Silicone Resin,Heat Resistance Silicone Resin.
