Recommended dosage of polymeric dispersing agent in paint

2021-09-29   Pageview:334

For good performance, D-346 should be added before the pigments are added at the grinding stage.

The following dosage is based on the ratio of the active ingredient of the dispersant to the amount of pigment:

Inorganic pigments: 10% according to oil absorption

Organic pigments: 15-20% by BET

Carbon black: 20% by BET

 

 

 

 

 

 

 

 

 

 

 

 

 

Emulsifiers or spreaders are also very important, because they can adjust the compatibility of the active ingredients in the coating system to achieve a balance of compatibility and incompatibility. Make the active ingredients reach the required particle size and play a defoaming effect. They can also ensure that the active ingredient penetrates into the surface film, rapidly diffuses and penetrates the surface of the coating film sharply, so that the active ingredient has an immediate defoaming effect. The emulsifiers or spreaders that can be used are: fatty acid ester, sulfonated fatty acid, fatty acid sulfurized succinate, octyl or nonylphenol polyoxyethylene puzzle, sorbitan (sugar) alcohol ester and its ethoxylate, etc.

Silicone defoamer
Silicone defoamers generally refer to two types of chemical substances: one type is mainly polydimethylsiloxane, in some cases, it can also be ethyl and part of hydroxy, phenyl, cyano, trimethyl Fluoropropyl and other siloxanes; the other is polyether or organic modified polydimethylsiloxane.

(1) Polydimethylsiloxane antifoaming agent Polydimethylsiloxane is a non-volatile oily liquid, which is insoluble or poorly soluble in water, animal and vegetable oils and mineral oils, and is resistant to high temperatures and Low temperature, stable physical properties. It is chemically friendly, has no biological activity, and has a very low surface tension. It is a widely used defoamer. When polydimethylsiloxane is used as a defoamer, its degree of polymerization n value is tens to hundreds. Relatively short-chain polysiloxanes are often used as surface additives for coatings and often show stable foam in coatings.

wax dispersion vs diffusion

The nature of the foam, whether it is stable foam or defoaming, depends on the solubility and compatibility of the siloxane used. Only by choosing a suitable solubility and compatibility siloxane product can it have the defoaming function. It is a description of pure polydimethylsiloxane, and the controlling factor is molecular weight or chain length. Lower molecular weight products can have the functions of leveling and surface smoothness; higher molecular weight and completely immiscible can be used as additives for hammer paint, and only properly mixed can be used as defoamers.

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