Antigua and Barbuda What are the Free of silicone defoamers for paints(1)
Leveling principle
The compatibility of acrylic leveling agents is an important indicator of their ability to control the surface state of the coating film. The compatibility is too good to dissolve in the coating film, which will not form a new interface on the surface of the coating film and provide no leveling effect; Due to poor compatibility, it is impossible to uniformly distribute on the surface of the coating film, which can gather together and easily cause shrinkage defects. It can reduce the gloss of the coating film and produce adverse side effects such as fog and shadow. Only with ideal controlled compatibility can a new interfacial layer be formed on the surface of the coating film, playing a leveling role
Antigua and Barbuda Selection of antifoaming agents for different applications:
Flat coating
affect
agent
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
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Polyether polyester modified organosiloxane
An organic polysiloxane with a comb like structure. N+m is about 50-250, and the molecular weight is controlled between 1000-150000. Its compatibility is adjusted by polyethers and polyesters, and the longer the chain, the better the phase compatibility. Polyether modifications are the most common in this category, typically using ethylene oxide and propylene oxide. With the increase of the content of ethoxy groups, their compatibility with water also improves, so it is also possible to synthesize water-soluble siloxane type leveling agents. Ethylene oxide and propylene oxide can be used alone or mixed to control hydrophilicity and lipophilicity. If both ethoxy and propoxy groups are contained, a silicone based leveling agent for both water and oil use is prepared,
Explanation in reference book
An agent that promotes the uniform dispersion of material particles in the medium to form a stable suspension. Dispersants are generally divided into two categories: inorganic dispersants and organic dispersants. Commonly used inorganic dispersants include silicates (such as water glass) and alkali metal phosphates (such as sodium tripolyphosphate, sodium hexametaphosphate, and sodium pyrophosphate). Organic dispersants include triethylhexyl phosphoric acid, sodium dodecyl sulfate, methyl pentanol, cellulose derivatives, polyacrylamide, gum, fatty acid polyethylene glycol esters, etc.
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Surface coating and film covering adhesive
and
Recommendation: Polyethers, which can effectively prevent surface defects and have a small impact on gloss
Water in Water Colorful
Features: More surfactants, stable foam
Antigua and Barbuda Recommendation: Use polyethers or mineral oil to modify polyethers
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