Preparation Of Acrylate Emulsion With Excellent Water-whitening Resistance And Application On Water In Water Multicolor Coatings

Water in water multicolor coating has rich colors and its film look like granite with good decorative, moreover, it possess environmental safety, simple construction technology, energy saving, cost-effective and so on, which has been widely favored by people and becoming hot products of building facades decoration field. However, currently, the promotion and application of water in water multicolor coatings are hindered by bleed, string and gather of color granule, after thickening, lack of stability and films with poor water-whitening resistance. So, improve of water-whitening resistance and stability of water in water multicolor coatings are the problems that urgent need to solve.This paper prepared organosilicon modified acrylic emulsion using emulsion polymerization, which has been used as resin in the basic coating and continuous phase of the water in water multicolor coatings. At the same time, synthesis methods and processes of organosilicon modified acrylic emulsion and effects on water-whitening resistance were systematic analyzed using organo-bentonite (GTS) as protective colloid of water in water multicolor coatings, in addition, formulation of water in water multicolor coatings were also discussed. Details of research and results are as follows:1. Organosilicon modified acrylic emulsion were prepared by semi-continuous emulsion polymerization using methacryloxy propyl trimethylsiloxy silane (AC-63), 3-(triethoxysilyl)propyl methacrylate; 3-(triethoxysilyl)propyl 2-methylprop-2-enoate (AC-636) and 3-methacryloxypropyltris-(trimethylsiloxy)-silane (AC-638) as modified monomer respectively, methyl methacrylate (MMA), methacrylate (MAA), butyl acrylate (BA) and 2-ethylhexyl acrylate (2-EHA) as raw materials with polymerization temperature of 80 ?. Factors to water-whitening resistance and other properties of the films were studied, such as polymerization process, type of monomer, initiator, emulsifier, glass transition temperature (Tg), MAA and organosilicon monomer. Results show that more stable polymerization process, less gel content of emulsion polymerization, good film formation, excellent water-whitening resistance, good compatibility with protective colloidt GTS were obtained by emulsifier and initiator 1.5% and 0.22% of the total amount of the monomer, theory Tg of the resin was designed as 6 ?, using pre-emulsification process, MAA and 2-EHA as major copolymerization monomer, MAA as functional monomer with 1% of the total amount of the monomer, AC-638 as organosilicon modified monomer with 4% of the total amount of the monomer and added before 0.5h of the end of the reaction.2.GTS as protective colloidt, homemade organosilicon modified acrylic emulsion as resin of water in water multicolor coatings, factor to the properties of coating were systematically analyzed, such as emulsion (used in the basic coatings), hydroxyethyl cellulose ethers, fillers, thickeners, protective assistants, protective colloidt and continuous phase. Results show that water in water multicolor coatings with excellent storage stability, water-whitening resistance and good decorative, colorful granules with clear boundary, high contrast and good strength were obtained by using emulsion, hydroxyethyl cellulose, kaolin and protective assistants 21-28%,0.7%,5-10%, and 0.5% of the total amount of the basic coating, concentration of GTS as 6%-8%, mass ratio of protective colloidt and basic coating as 5:7 to 7:7, thickeners in the continuous phase as 0.5%, mass ratio of continuous phase and basic coating as 5:7.