All about silicone resin: features,types,applications

26th January 2024

What is silicone resin?

Organic silicone resin, also known as silicone resin or siloxane resin, refers to organic polymers containing Si-C bonds in their molecular structure. Silicone monomers, prepolymers, and resins can also be collectively referred to as organosilicon compounds. Coatings prepared from them as film-forming materials are called silicone resin coatings, or simply silicone paints.

Features of silicone resin

Due to the presence of relatively stable siloxane bonds in organosiloxane condensates, similar to inorganic silicate structures, both liquid, solid, or elastomeric polymers exhibit high heat resistance, chemical stability, excellent electrical insulation, and very good hydrophobicity.

  • High Temperature Resistance: Generally, synthetic resins have a heat resistance of around 150°C, while organic silicone coatings can be used for prolonged periods at temperatures up to 200°C. With the addition of high-temperature resistant pigments or aluminum powder, the heat resistance can reach 400or 500°C, and special coatings can withstand temperatures of 800 or 900°C. Therefore, they are suitable for coating (dipping or spraying) high-temperature components.
  • Electrical Insulation and Hydrophobicity: The presence of a layer of non-polar organic groups and molecular symmetry on the outside of the main chain of organosiloxane resin molecules provides excellent electrical insulation and hydrophobicity.
  • Cold Resistance: Due to the weak intermolecular forces in the large molecular structure and non-polar molecules of organosiloxane resin, it exhibits good cold resistance. The cold resistance of pure organosiloxane coatings is generally around -50°C, while polyester-modified organosiloxane coatings can withstand temperatures below -80°C.
  • Mold Resistance: Because organic silicone coatings do not contain oily components, fungi cannot survive on the coating film, giving organic silicone paint excellent mold resistance, making it suitable for coating components with special requirements for mold resistance.

 2 types of silicone resin

Classified by the type of film-forming material, coatings can be divided into pure organosiloxane coatings and organosiloxane-modified resin coatings. Pure organosiloxane resin coatings exhibit outstanding heat resistance and insulation, displaying excellent weather resistance and corrosion resistance in high-temperature environments, making them excellent high-temperature insulation coatings. Organosiloxane-modified resin coatings include organosiloxane-modified phenolic, alkyd, polyester, acrylic, epoxy, and polyurethane resins. Depending on the amount of organosiloxane material used, the heat resistance, weather resistance, corrosion resistance, flexibility, and other properties of the modified resin can be improved to varying degrees. Additionally, the film-forming properties of organosiloxane resins can also be enhanced.

Organosiloxane-modified alkyd resin coatings, when organosiloxane is used appropriately, can increase weather resistance by up to 4 times; significant improvements in heat resistance and corrosion resistance are observed, elevating the overall coating performance. Organosiloxane-modified alkyd resin coatings are extensively used for the painting of high-voltage transmission line towers, railway and highway bridges, trucks, power stations, oil extraction equipment, outdoor chemical installations, and agricultural machinery. They are also commonly employed in corrosion protection coatings for metal and plastic, coatings with good weather and chemical resistance, excellent adhesion, printing inks, as well as for above-waterline treatments of ships and weather-resistant coatings for industrial use.

Organosiloxane-modified polyester-amino coatings can increase their operating temperature range from 120-150°C to 180-200°C , with noticeable improvements in weather resistance and corrosion resistance. One primary application of organosiloxane-modified polyester-amino coatings is for coil coatings, enhancing their resistance to acid rain corrosion and weathering, thereby expanding their application scope in colorful sheet metal construction.