Chem(Yueyang) Waterborne Additive Co., Ltd
Address: Chenglingji Linggang Industrial New Area, Yueyang, Hunan
Address: 220, He'anbao Commercial Building, No. 1105, Zhongshan Avenue
Address: Room 2415, Block B, Modern Plaza, No. 8, Weiye Road, Kunshan City, Jiangsu Province
Tel:+86 -512- 50176956
Fax:+86 -512- 50176956
Substrate wetting agent
When screening substrate wetting agents, we generally need to consider: the surface energy of the substrate, construction technology (such as high-speed roller coating, spray coating, shower coating, etc.), drying conditions, and system pH.
Due to the high surface tension of water (more than 70mN/m), which is greater than that of various common substrates, it is difficult for water-based coatings, inks, etc. to wet the corresponding substrates. Therefore, it is necessary to add a substrate wetting agent to the water-based formulation to reduce the surface tension of the system and increase the wetting and spreading of the substrate.
Development trend of substrate wetting agents for waterborne industrial coatings and inks:
- Unstable foam, with defoaming or defoaming function;
- Strong ability to reduce dynamic surface tension;
- Does not affect the water resistance of the coating;
- Good hydrolytic stability;
- Does not affect intercoat adhesion
Common wetting agents for water-based industrial coating systems include acetylene glycol surfactants, polyether-modified silicones, and fluorosurfactants.
Fast diol-based wetting agents have a strong ability to reduce dynamic surface tension, are not stable in foam, have certain defoaming ability, and have low water sensitivity. Because of its hydrocarbon chemical structure, it has good stability in the system, and the effect is obvious in the water-based system of high-speed construction, and it is safe and difficult to produce other side effects.
Polyether-modified siloxane-based substrate wetting agent has a wide range of adjustable structures and outstanding performance in reducing static surface tension, which can reach about 20mN/m. It has very excellent spreadability and permeability. Oxygen bond exists, the hydrolytic stability is poor in some highly acidic and alkaline systems, and most of them have a tendency to stabilize foam. The silicone chain segment in its molecular structure is generally short and the molecular weight is small, so it has little effect on recoatability and generally does not provide slipperiness.
Fluorine-containing surfactants are the substrate wetting agents that reduce the surface tension the lowest, which can reach 17mN/m. Due to the existence of fluorine-carbon bonds, they can resist acid, alkali and high temperature, and can also endow the coating surface with water resistance and stain resistance. Pollution. But at the same time, the price is generally high, and the foam stability and foam production are high. When using it, it is necessary to pay attention to the combination with the defoamer, which limits its wide use.