The performance of silicone resin The use of silicone resin

Nov 30, 2021

Silicone resin is a collective term for a type of polymer in which silicon atoms and oxygen atoms are alternately connected to form a skeleton, and different organic groups are connected to silicon atoms. The structure of silicone resin contains both "organic group" and "inorganic structure". This special composition and molecular structure make it a combination of organic and inorganic functions. The following editor introduces the properties of silicone resins and the uses of silicone resins.
Performance of silicone resin

1. High temperature resistance
Generally, the heat-resistant temperature of synthetic resin paint is below 150℃, while silicone paint can be used for a long time at 200℃. If high-temperature pigments are added, the heat resistance can reach 400°C ~ 500°C, and special ones can also reach 800°C ~ 900°C. Therefore, it is suitable for coating high temperature resistant parts.

2. Electrical performance and hydrophobicity number
Since the outer layer of the silicone paint molecule has a layer of non-polar organic genes and molecular symmetry, it becomes the basic reason for its good electrical insulation properties and water repellency. In terms of insulation, it not only has high insulation resistance, but also shows excellent performance in terms of breakdown range and resistance to high-voltage arc sparks. Therefore, it can be used to impregnate motors and components with high insulation performance requirements to improve insulation components. Insulation class.

3. High surface activity and low tension
Since polysiloxane is a symmetric molecule and its substituents are non-polar organic groups, the entire molecular formula is non-polar. The force between the molecules is small, and the cohesion of the molecules themselves is also small, so the surface tension is small. When it is dispersed on the surface of the medium with high surface tension, the medium can be separated, and because the force between itself and the molecules of the medium is also small , So it can reduce the surface tension of the medium and make it difficult to form foam. This is the reason why silicone oil can be used for defoaming in paint making. Therefore, it can be used as a defoamer and leveling agent in paint to prevent luminescence and pitting of the paint film. The dosage is 0.2% ~ 0.3%.

4. Good cold resistance
Due to the structure of the organic silicon paint macromolecules, the attraction between the molecules is weak, which gives it good cold resistance. The cold resistance of pure silicone is about -50°C, while the polyester-modified silicone paint W31-1 can withstand temperatures below -80°C. Therefore, the paint can be used in colder places.

5. Good chemical resistance
Due to the existence of ether bonds in silicone paint, it has good inherent chemical resistance. For example, the paint film is immersed in 2% acetic acid: 10% hydrochloric acid, 10% nitric acid, 10% sulfuric acid, 10% caustic soda, 10% sodium nitride or butanol, kerosene. After 100 hours, the paint film is still good.

6. Good mildew resistance
Because the silicone paint does not contain oil components, molds cannot survive on the silicone paint film, so that the silicone paint has better anti-mildew properties and is suitable for coating on parts that require special anti-mildew properties.
Uses of silicone resin

1. Electrical insulating paint: The volume, quality and service life of electrical appliances have a great relationship with the performance of electrical insulating materials. Therefore, the industry requires the use of a variety of electrical insulating varnishes, including coil impregnating varnish, glass cloth impregnating varnish, mica bonding insulating varnish and silicone varnish for electronic and electrical protection.
2. Coating: Silicone resin has excellent characteristics of heat resistance, cold resistance, weather resistance, water repellency, etc. In addition, it can obtain colorless and transparent coatings with good adhesion and wear resistance. Anti-sticking and release coatings and moisture-proof and water-repellent coatings .
3. Adhesive: There are two types of polysiloxanes used as adhesives: silicone type and silicone resin type, and there are differences in structure and crosslinking density between the two. Among them, there are differences between pure silicone resin type and modified type resin for resin type adhesives.
4. Plastics: mainly used in heat-resistant, insulating, organic and arc-resistant silicone plastics, semiconductor component shell packaging plastics, and foam plastics.
5. Micropowder and trapezoidal polymer: Compared with inorganic fillers, silicone resin micropowder has a low relative density, and at the same time has the characteristics of heat resistance, weather resistance, lubricity and water repellency. The trapezoidal silicone resin has higher heat resistance, electrical insulation and flame resistance than the silicone resin with a general mesh three-dimensional structure.

Silicone resin composite
1. Organic silicon glass varnish cloth is made by impregnating glass cloth with organic silicon resin and drying. Mainly used as wrapping insulation or lining thermal insulation material for electrical appliances and motors.
2. Silicone laminated plastic, laminated glass cloth impregnated with silicone resin, and made products by high pressure molding, low pressure molding or vacuum bag molding method. It can be used for a long time at 250°C, and the short-term use temperature can be as high as 300°C. Mainly used for slot wedge insulation of H-class motors, high-temperature relay shells, high-speed aircraft radomes, printed circuit boards, etc.
3. Organosilicon mica products, according to the type of silicone insulating resin selected and the structure of mica, a variety of hard or soft products can be obtained, such as mica foil, mica tape, mica plate, etc., mainly used for H-class electrical and electrical insulation Material.
4. Silicone film compression plastics, using silicone resin as the base material, adding quartz powder, white carbon black and other fillers, rolling, and crushing to make molded materials. It has good fluidity at 150°C and can cure quickly. Asbestos-filled organic silicon film pressed products can work at 250°C for a long time, and the instantaneous working temperature can be as high as 650°C. Now they are widely used in aviation, aerospace, and electronic and electrical industries.