Redispersible latex powder is a powder obtained by spray-drying a polymer emulsion and then adding modified substances, which can be redispersed to form an emulsion when it meets water. Redispersible latex powder is mainly used as an additive for dry-mixed mortar, which has the functions of improving the workability of mortar, improving fluidity, improving cohesion, and increasing bonding strength. It is a new type of environmentally friendly material. At present, latex powder needs to be added to tile bonding, external wall insulation, self-leveling, putty powder, etc. to improve the bonding and sag resistance of mortar.
The polymer emulsion used in redispersible latex powder is mainly polymer emulsion formed by adding one or two monomers to vinyl acetate as a monomer in China. Currently, vinyl acetate-ethylene copolymer emulsion, vinyl acetate – Mainly ethylene tertiary carbonate copolymer emulsion, additives will be added to the latex powder produced to improve anti-caking and redispersibility. However, due to the structure of vinyl acetate, its original strength and water curing strength are not good in terms of adhesion to insulation boards and cement substrates.
Acrylic emulsion has good water resistance and is widely used in the building materials industry, but its direct drying and powder spraying process is immature, and its proportion in redispersible emulsion powder is very small, and the adhesion of acrylic emulsion is poor, and it is sticky to mortar. Insufficient improvement in bonding strength limits the use of acrylic emulsions.
The purpose of the novel acrylic latex powder and the preparation method thereof is to obtain latex powder products with high cohesive strength and good adhesion.
1. The redispersible latex powder has excellent cohesiveness, which can improve the cohesion of building mortar, improve the adhesion between mortar and base material, and improve the workability. It is suitable for building materials and mortars that require high bonding strength. field, the market prospect is broad.
2. In the formulation system of the redispersible latex powder, a variety of polymer emulsions based on acrylic emulsion are selected and mixed according to the appropriate ratio, which can give full play to their respective advantages, improve the performance of the latex powder, and expand the scope of the latex powder. scope of application.
3. In the preparation of the redispersible latex powder, the spray liquid is directly heated by online heating, which improves the redispersibility of the latex powder.
4. In the formula system of the redispersible latex powder, two kinds of mixtures of calcium carbonate, talcum powder, kaolin and silicon dioxide are selected as anti-caking agents with a mass ratio of 1:1-2, so that the latex powder particles The wrapping is more uniform and the anti-caking property of the latex powder is improved.
5. In the formulation system of the redispersible latex powder, one or a mixture of the silicone defoamer and the mineral oil defoamer is selected as the defoamer at a mass ratio of 1:1, which improves the The film-forming property of latex powder improves the bonding strength of mortar.
6. The preparation process of the redispersible latex powder is simple and easy to realize industrialization.