Acrylic emulsions synthesized from acrylic acid or acrylic esters as the main raw materials have excellent light stability and weather resistance, good water resistance, alkali resistance, chemical resistance and adhesive properties, so they are widely used. Used as adhesives, coating film-forming agents, daily chemicals, chemical power supplies, functional films, medical polymers, nanomaterials, and water treatment. However, acrylate emulsion has shortcomings such as becoming brittle at low temperatures, becoming sticky and losing strength at high temperatures, and easy to stick back, which limits its application scope and value. In recent years, with the continuous improvement and development of polymerization technology and people's emphasis on environmentally friendly products, the modification of acrylic emulsions has received widespread attention. Generally speaking, acrylate emulsions are modified mainly from two aspects: one is to introduce new functional monomers; the other is to adopt new emulsion polymerization technology. Acrylic polymers have excellent film-forming properties, adhesion, gloss retention, weather resistance, corrosion resistance and flexibility. However, it is thermoplastic and lacks cross-linking points on its linear molecules, making it difficult to form a three-dimensional network cross-linked adhesive film. Therefore, it has poor water resistance and stain resistance, and is prone to becoming brittle at low temperatures and sticky at high temperatures. The Si-O bond energy (450kJ/mol) in silicone resin is much larger than the C-C bond energy (351kJ/mol), the internal rotation energy barrier is low, the molecular molar volume is large, the surface energy is small, and it has good UV resistance and weather resistance. properties such as resistance to stains, stains and chemical media. Using organic cinnamon to modify acrylic emulsion can combine the advantages of both, improve the "hot viscosity, cold brittleness", weather resistance, water resistance and other properties of acrylate emulsion, and expand its application scope to adhesives, exterior wall coatings, and leather finishing agents. , fabric finishing agents and printing and other fields.
Organic silicone modified polyacrylate is divided into two methods: physical modification and chemical modification. Among them, there are usually two methods for physically modifying acrylic emulsions with organosiloxanes: First, organosiloxane monomers are directly added to acrylic emulsions as adhesion promoters and coupling agents. Modification; the second is to first make the organic siloxane into an organic emulsion, and then cold-mix it with the acrylic emulsion for modification. Chemical modification method is a method based on the chemical reaction between polysiloxane and polyacrylate, thereby organically combining silicone molecules with polyacrylate. Through chemical modification, the compatibility of polysiloxane and polyacrylate can be improved, and the surface migration of silicone molecules can be inhibited to evenly disperse the two, thereby improving the physical and mechanical properties of polyacrylate polymer emulsion. . Depending on the silicone material, the following three methods can be used (1) Siloxanes containing double bonds, especially siloxane oligomers containing double bonds, are polymerized with acrylate monomers to produce side chains containing silicon. Comb-shaped polymers of oxane or polymers containing siloxane in the main chain; (2) Silicones with hydroxyl groups and acrylates with hydroxyl groups form graft polymers through condensation reactions ; (3) Hydrogen-containing polysiloxane and acrylate are polymerized under the action of platinum catalyst. Epoxy modified acrylate introduces propylene unsaturated double bonds at both ends of the molecular chain of the emulsion epoxy resin, and then polymerizes it with other monomers. The resulting emulsion has the high modulus and high strength of the epoxy resin. , chemical resistance and excellent anti-corrosion properties, and has the gloss, fullness and weather resistance of acrylic, and is low in price. It is suitable for occasions with particularly high decorative requirements, such as plastic surface coating and processing. (Such as surface treatment, electroplating, hot stamping, coating, etc.) needs. The synthesis reaction of epoxy acrylate emulsion is a free radical polymerization mechanism. Although epoxy resin does not have unsaturated double bonds, it does contain ether bonds. The α-H on the ortho-position carbon atom is relatively flexible and plays a role in the role of initiator free radicals. Free unsaturated monomer graft polymerization can be formed under the conditions to produce epoxy acrylic resin. The final product of the polymerization reaction is ungrafted epoxy resin, graft-polymerized epoxy resin and acrylate polymer. mixture.