Characteristics and Uses of Silicone Resin

1. What is silicone resin.

Silicone resin is a term often confused with silicon atoms, silicon metal, and silica. Silicon refers to silicon atoms or silicon metal, while silica denotes silicon dioxide (SiO2). In contrast, silicone resin refers to a substance containing Si-O-Si bonds, known as polyorganosiloxane. 

2. Silicone Paint and Silicone Resin 

Architectural exterior ‘silicone (resin) paint’ is made not only with silicone resin but also with resins that contain silicon atoms. This paint uses two binder resins with Si-O-Si bonds. (A) One uses silicone resin to modify acrylic and polyester resins, while (B) the other employs acrylic resin with alkoxysilane groups. There are both curing processes involving alkoxysilane groups and pre-crosslinked room-temperature drying emulsion resins. 

3. Features 

Si-O-Si bonds have strong bonding energy, making them resistant to UV rays and heat, and providing excellent weather resistance, water resistance, heat resistance, and chemical resistance. These properties can be improved by incorporating them into acrylic and polyester resins. Weather resistance depends on the content of siloxane chains. In a comparison of coatings, where (1) pure acrylic resin, (2) acrylic resin with alkoxysilane groups (mentioned above B), and (3) acrylic resin with silicone resin grafting using polyisocyanate crosslinking (mentioned above A), (3→2→1 show a trend of high weather resistance. However, excessive silicone content can reduce adhesion and recoatability, so caution is necessary. 

4. Usage 

As a binder, there is a heat-resistant paint that consists solely of pure silicone resin. Its heat resistance can reach temperatures of 200-250°C. When aluminum powder or ceramic powder is added, it can be used at temperatures of around 700°C. On the other hand, the modified resins mentioned earlier are known for their high weather resistance and are typically used in heat-cured and emulsion-type coatings. 

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