Application Of Silica Sol In Waterborne Wood Coatings

Traditional home decoration coatings are organic coatings (commonly known as paints), and their volatile organic solvents are very harmful to the environment and human health. Countries around the world have formulated strict environmental protection regulations to limit industrial emissions. Engineers have also designed water-based coatings with low VOC emissions. The main components of water-based coatings are polymer emulsions and some additives. Water is used as a solvent or dispersant. It is a green, environmentally friendly and healthy coating variety. However, water-based resins currently have some defects in the application process, such as low hardness and poor wear resistance. In terms of comprehensive performance, they still cannot meet the performance indicators of traditional oil-based paints, and the market promotion in the field of wood paints is weak. Modifying water-based resins to obtain water-based coatings comparable to traditional oil-based paints is a key technical problem that needs to be urgently solved in the field of coatings. In the formula of water-based wood paint, adding a special silica sol component can increase the hardness of the coating, improve the aging resistance and water resistance of the coating film, and improve the anti-adhesion properties of the coating film. Therefore, silica sol-modified water-based wood paint has become a hot spot in the research of the coating industry.

1. Silica sol can improve the hardness and anti-adhesion of water-based wood paint.

When an appropriate amount of silica sol is added to the water-based wood paint, the silica particles will fill the three-dimensional network structure formed by the polymer chain during the drying process of the coating. At the same time, the silica particles themselves will condense to form a -Si-O-Si-network structure. The addition of inorganic rigid nano-silica particles makes the coating harder and more scratch-resistant, which increases the service life of the coating. The hard nano-silica particles in the silica sol component can also enhance the anti-adhesion of water-based wood paint.

Silica particles are cross-linked to form a three-dimensional network structure

2. Silica sol can improve the heat aging resistance of water-based wood paint

The cured coating contains a large amount of nano-silica particles, which have extremely strong ultraviolet absorption and infrared reflection properties, and can shield the coating, thereby improving the ultraviolet aging resistance and heat resistance of the coating.

3. Silica sol can improve the water resistance of water-based wood paint

Nano-silica sol has a small particle size and has good penetration, hardening and bonding properties. It can easily enter the tiny holes of wood or fiberboard and fill and seal these holes. Waterborne wood coatings containing nano-silica particles form a cross-linked network of inorganic particles after drying and forming a film, which can form a water-insoluble coating together with the resin, thereby improving the water resistance of waterborne wood coatings.

It should be noted that ordinary silica sol cannot be used in waterborne wood coatings, because ordinary silica sol has poor compatibility with resins, which will cause post-thickening and gelation. Only modified special silica sol can be used in waterborne wood coatings.