Malaysia What are the Free of silicone defoamers for paints(1)

Malaysia Selection of antifoaming agents for different applications:

Flat coating

black

adhesion

dispersant

Features: Low viscosity, low defoaming pressure

Recommendation: Mineral oils or mineral oil modified polyethers

Elastic coating

Features: High viscosity, high Free of silicone defoamers pressure

Recommendation: Polyether modified silicone

The study of foam can be traced back to Plato's time, but for hundreds of years, people have not formed a unified understanding of the definition of foam. American colloid chemist L · I · Osipow and Dow Corning's R · F · Smith defined foam from the density of foam; Japan's Koichi Ito defined foam from the perspective of foam structure, but ignored the correlation between bubbles; Professor Zhao Guoxi, a famous surface physicist in China, defined foam as: foam is a dispersion system in which gas is dispersed in liquid, gas is a dispersed phase (discontinuous phase), and liquid is a dispersion medium (continuous phase). Bubbles in liquid rise to the liquid surface, forming a bubble aggregate composed of a small amount of liquid that separates gas with liquid film. Scholars at home and abroad agree that foam itself is a thermodynamic unstable system. When the gas enters the solution containing surfactant, it will form a long-term stable foam system.

agent

Surface coating and film covering adhesive

Recommendation: Polyethers, which can effectively prevent surface defects and have a small impact on gloss

Water in Water Colorful

Features: More surfactants, stable foam

affect

Dispersant is a kind of interfacial active agent that has both opposite properties of lipophilicity and hydrophilicity within the molecule. It can uniformly disperse solid and liquid particles of inorganic and organic pigments that are difficult to dissolve in liquids, while also preventing particle sedimentation and condensation, forming amphiphilic reagents required for stable suspensions

Malaysia Recommendation: Use polyethers or mineral oil to modify polyethers

The larger the molecular weight, the stronger the control ability of its surface state, and the better its skid resistance and adhesion resistance, such as the 1070 and 1071 series products of the friction chemical industry.
There are two methods for bonding modified polyester or polyether to siloxanes: one is a silicon oxygen bond; The other is silicon carbon chains, which generally have less thermal stability and water resistance than the latter.
The compatibility of polyether and polyester modified siloxanes with resins has been greatly improved, reducing surface tension, controlling surface flow, increasing slip resistance, anti shrinkage, and anti adhesion. Some products also have interlayer adhesion issues. In particular, polyether modified polysiloxanes have poor thermal stability and are prone to foam stabilization. It is important to pay attention to the negative effects of these products when applying them.

Precautions for use of paint Free of silicone defoamers:

Before use, stir thoroughly and mix evenly; Adding the paint while stirring; Before use, it is generally not diluted with water; The dosage should be appropriate. Excessive dosage can cause shrinkage, edge shrinkage, poor brushing performance, and other problems; Too little dosage leads to poor defoaming effect; Add it in two stages, namely, add it in the grinding stage and the paint mixing stage, generally accounting for half of the total amount each time. Use defoaming agents with good foam suppression effect in the grinding stage, and use defoaming agents with good foam breaking effect in the paint mixing stage