High-solid coatings have the advantages of reducing pollution and reducing processes. It is one of main green automobile coatings. High-solid acrylic resin can be rapidly solidified under high temperature without affecting its luster and color, and has good hardness, weatherability, color retention, adhesion and flexibility. Therefore, the acrylic resin is widely used in the automotive industry. The silane coupling agent with high weatherability has similar activity to acrylic acid, so it’s easy to copolymerize. It has become an important method for acrylic resin modification.
The hydrophobicity of coating surface can be increased by adding silane coupling agents in the polymer chain, because of similar activity (methacryloxy of silane coupling agents and methacrylic acid). They are to form a random copolymer after polymerization. Therefore decrease surface energy of the copolymer membrane and the water contact angle increases slightly. The hydrophobicity of the resin increases with the introduction of silane coupling agent, and the water contact angle increases with increasing amount of silane coupling agent, and the pencil hardness increases from 2H to 4H.
silane modified high-solid acrylic resin has higher pencil hardness, good adhesion, impact resistance, acid resistance and alkali resistance. With silane coupling agent content increasing, these properties gradually improve. And the water contact angle increases with the increase of silane coupling agent. It shows that the net crosslinking structure formed by the silane coupling agent and the high-solid resin makes the hydrophobicity of the coating surface increase gradually.