The analysis of the effect of emulsion for waterborne exterior wall coating development ( Eight)

The development trend of waterborne architectural coatings emulsion water-based emulsion is focused on the development of architectural coatings meet increasingly stringent market performance requirements, reduce volatile organic compounds, reducing environmental harm. Current production of emulsioni paint usually contains a small amount of organic solvent, helps to film. People have been trying to volatile organic compounds to further reduce to zero. Let's talk about reducing volatile organic compounds. Fire is usually designed to replace the lauryl alcohol ester film-forming additives. For many years, the domestic and foreign giants are no less effort. Solvay - Rhodia, dow chemical, Eastman and other companies launched alternatives. What dahl, system function, OE300, OE400, even TXIB play a role, in fact, all do not accord with standard of zero volatile organic compounds. Personally, I think finding an alternative to of lauryl alcohol ester film forming additive is very difficult and even in vain, because the boiling point is only more than 100 degrees of propylene glycol was used as antifreeze in latex paint inside and outside. You should replace the antifreeze. The boiling point of 12-12 alcohol ester is not lower than 250 ℃. In recent years, in the emulsion polymer plasticized in focus. For example, the introduction of ethylene and vinyl acetate copolymerization monomer form of VAE emulsion, due to the glass transition temperature was minus of polyethylene 68 ℃, ethylene in the main chain has a strong internal plasticization effect, it is easy to adjust its glass transition temperature of the copolymer emulsion. Because of the vinyl acetate - Ethylene copolymer emulsion with the above characteristics, its solvent-free emulsioni paint market dominance in Europe. Solvent-free emulsioni paint refers to the excluding film additives and solvents, so as to realize zero volatile organic compounds. One of the most attractive method is mix hard latex and soft latex for zero voc latex paint. Due to the glass transition temperature of soft emulsion under room temperature, even if it is mixed with a lot of hard emulsion without adding film additives, film can also be dry and formed at room temperature. When formed by dry film, soft emulsion polymer deformation in order to fill the gap and through the continuous phase, and hard emulsion polymer with good adhesion resistance coating. When hard emulsion thin enough, after drying the polymer can be evenly distributed in the soft emulsion polymer substrate, when two similar refractive index of polymer emulsion membrane can be transparent. Of course, the hybrid emulsion dry faster than any one of two kinds of hybrid emulsion is slow. The hybrid emulsion not only use film forming additive, also used antifreeze and thawing agent at low temperature. Common emulsion can not meet the requirement of the decorative coating performance enhancement, development of new varieties need time and manpower. By polymer blending modification, however, can develop more faster, better and more economic the different performance of the emulsion. If the silicone acrylic emulsion blending modification, can reduce the bibulous rate of coating increase permeability, and is more effective and more durable protection and adornment wall. Organic silicone emulsion and acrylic latex blend modified latex paint can be a high PVC, therefore has many porosity and good permeability. The addition of organic silicone emulsion is not closed capillary hole, but as a result of organic silicon resin of low surface energy, water proofing property is greatly increased, so as to realize high permeability and low water absorption. As for the improvement of durability, one of the reasons is the silica silicone key energy is high, not easy damaged by uv. Second, the oxygen and water, under the joint action of uv accelerated the degradation of polymer coating, light oxidation degradation of promote the hydrolysis, which accelerated the light oxidation degradation. Oxygen always exists, but silicon resin has good water repellency and permeability, keep the film dry state, greatly reduces the common damage of water, thus effectively ease the uv effect on the degradation of polymer coating; Third, dry coating, reduce freeze-thaw damage. Fourth, the dry film, there is no fungi and algae to produce water. Mixed with siloxane emulsion can be a pure acrylic emulsion or styrene acrylic emulsion. Combine the advantages of alkyd emulsion and acrylic emulsion is the easiest way to mix. Blending modification of acrylic acid emulsion for polyurethane dispersions wet paint not well, so their color other than some easy. With a certain amount of acrylic acid emulsion preparation of pigment dispersions, and polyurethane dispersions blend, not only can solve the problem of coloring, and reduce the cost. Instead, add a small amount of flexible polyurethane (pu) in acrylic emulsion as plasticizers, polymer can greatly reduce the dosage of film forming additive, in order to gain good acrylic film forming performance. To add appropriate PUD will make acrylic acrylic emulsion has the following properties. (1) improve the abrasion resistance and impact resistance. (2) improve the low temperature flexibility. (3) improve the coalescence, such as hardness increase rapidly. (4) improve early adhesion resistance. (5) improve chemical resistance and solvent resistance. 6. Improve the water resistance. This is the very hot PUA water-borne polyurethane emulsion acrylic dispersion. If in the process of emulsion polymerization to introduce some functional groups of cross-linking can be accomplished, in the process of film forming suitable three-dimensional cross-linked, so can greatly enhance the cohesive force of emulsioni paint, adhesion resistance, contamination resistance, solvent resistance and weather resistance and a series of defects. With the improvement of people performance requirements for architectural decoration paint, latex of development and research is rapidly advancing. We firmly believe that, made of various kinds of latex paint is rapidly replacing the low toxicity, little damage to the environment of the solvent coatings.