Update:Compared with traditional solvent-based coatings, water-based coatings have the advantages of low price, safe use, savin...
Compared with traditional solvent-based coatings, water-based coatings have the advantages of low price, safe use, saving resources and energy, reducing environmental pollution and pollution, and thus have become the main direction of the current development of the coatings industry. Water-based acrylic resin coatings are the fastest-growing and most diverse non-polluting coatings in water-based coatings.
Water-based acrylic resins
include acrylic resin emulsions, aqueous acrylic resin dispersions (also known as water-dilutable acrylics) and aqueous acrylic resins. Emulsions are mainly synthesized by emulsification of oily vinyl monomers in water under the initiation of aqueous free radical initiators, while resin aqueous dispersions are synthesized by different processes such as free radical solution polymerization or stepwise solution polymerization. Seen from particle size: emulsion particle size > resin aqueous dispersion particle size > aqueous solution particle size. From the application point of view, the first two are the most important.
Acrylic emulsion is mainly used as the base material of latex paint, and it occupies an important application in the architectural coatings market, and its application is still expanding; Applications in the field of coatings continue to expand. According to the monomer composition, it is usually divided into pure acrylic emulsion, styrene acrylic emulsion, vinyl acrylic emulsion, silicone acrylic emulsion, tertiary vinegar (tertiary carbonate-vinyl acetate) emulsion, tertiary acrylic (tertiary carbonate-acrylate) emulsion, etc.
Acrylic water-based paint can be divided into two categories: water-dispersible and water-soluble. The former is based on water emulsion or hydrosol. Water-soluble acrylate coatings are made of copolymer resins with active cross-linkable functional groups, multi-series thermosetting coatings, with or without cross-linking resins during paint making, so that active functional groups are cross-linked during film formation to form a body. Structural paint film. The development of water-based acrylate coatings can replace most of the organic volatile solvents with water under the condition of ensuring various unique properties of acrylate coatings, thereby achieving the purpose of greatly reducing air pollution.
Water-soluble acrylic resins are mostly of anionic type, and appropriate amount of unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic anhydride, methylenesuccinic acid, etc. are selected in the monomers of the copolymerized resin, so that the side chain has carboxyl groups. , and then neutralized with organic amine or ammonia water to obtain water solubility. In addition, the water solubility of the resin can be increased by selecting appropriate monomers to introduce hydrophilic groups such as -OH hydroxyl group, -CONH2 amido group or -O-ether bond on the side chain of the resin. The acrylic resin that is neutralized and formed into a salt is soluble in water, but its water solubility is not very strong, and it often forms an opaque liquid or a solution with high viscosity, so a certain proportion of hydrophilic auxiliary must be added to the water-soluble resin. solvent to increase the water solubility of the resin.