Water-based interior wall coatings have the characteristics of health, environmental protection and excellent performance due to the use of water as the dispersion medium, and have become the main variety of interior wall decoration materials. In the production process of water-based interior wall coatings, due to uneven dispersion of pigments and fillers or improper adjustment of rheology, a series of problems will occur in the storage, construction and film-forming stages of the coatings. scrapped. As a film-forming substance in water-based coatings, emulsion is the core component of coatings and plays an important role in determining its performance. How to make water-based interior wall coatings have good dispersion stability and storage stability, and improve the performance of coatings is a research topic that has both theoretical significance and engineering application value.
Firstly, the preparation technology of styrene-acrylic latex paint is studied in this paper. The crystal forms of titanium dioxide, calcined kaolin, talc, heavy calcium, diatomite and montmorillonite powder with different particle sizes, different dosages of sodium hexametaphosphate, SN-5040 and fast dispersant, and the factors such as stirring speed were investigated. The influence law of latex paint pigment slurry fineness, the influence law of pH value, thickener type and dosage on the viscosity of latex paint was systematically discussed.
The results show that using rutile titanium dioxide as pigment, best thickner emulsion for water based exterior emuldion paint, 1250 mesh calcined kaolin as filler, and 1.2% SN-5040 as dispersant, under the condition of stirring speed of 1500r/min, the prepared pigment slurry has good dispersibility. , When the dispersion time is 30min, the fineness of the pigment slurry is 20μm, the particle size of the latex paint is mainly distributed in the range of 1~10μm, and the viscosity stability is good. The viscosity of latex paint increases with the increase of the amount of various inorganic, cellulose and synthetic polymer thickeners; the viscosity of latex paints formulated with inorganic, cellulose and polyurethane associative thickeners respectively With the increase of pH value, it remained basically unchanged; the viscosity of latex paint prepared with alkali-swellable thickener gradually increased with the increase of pH value, and then gradually became flat.
At the same time, the synthesis process of silicone modified acrylate emulsion was studied in this paper. Butyl acrylate (BA) and methyl methacrylate (MMA) are used as acrylate soft and hard monomers, tetramethyltetravinylcyclotetrasiloxane (D4vi) is used as organosiloxane monomer, ten Sodium dialkyl sulfate (SDS) and OP-10 were used as emulsifier systems. The silicone-acrylic emulsion was synthesized by a combination of pre-emulsification, semi-continuous dropwise addition and seed emulsion polymerization. By discussing the effects of the ratio of soft and hard monomers, the ratio and amount of emulsifier, the polymerization temperature and the amount of organosiloxane monomers on the properties of the emulsion, the optimal process route for synthesizing silicone-acrylic emulsion was determined.
The results show that when m(BA)/m(MMA) is 49/49, m(SDS)/m(OP-10) is 1/1, the total amount of emulsifier is 4% of the total monomer, and The amount of alkane monomer is 10% of the total amount of monomer. Under the condition that the polymerization reaction temperature is 80 °C, the gel rate of the synthesized emulsion is 0.29%, the conversion rate of monomer is 99.34%, and the particle size distribution is uniform, and the average particle size is 89.47nm.
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