Лако-красочные материалы — производство

Epoxy resins prepared from the reaction between bisphenol A (BPA) and epichlorohydrin are commercially the most important ones, covering around 80 to 85 % of the volume of epoxy resins used in the industry. Various BPA epoxy resins available on the market pri­marily differ in their MW, and can be categorized as: • Low MW: […]

The majority of the commercially important epoxy resins are derived by reacting epichlorohydrin with various starting materi­als containing functional groups with an active hydrogen, such as a phenolic hydroxyl, hydroxyl, carboxylic acid, or amine. The initial reaction yields chlorohydrin, which upon subsequent dehydrochlo­rination yields a glycidyl group (Figure 2.37). Another class of epoxy resins and […]

Epoxy resins are a very important class of thermosetting synthe­tic polymers used in coatings, adhesives and composites. Epoxy resins are characterized by having three-membered epoxy (also called oxirane or epoxide) functional groups as reactive sites for cross-linking. A typical terminal epoxy group, as depicted below, is commonly known as a glycidyl group.

Radiation curable coatings are special types of systems that are cured by exposure of their wet films to high energy radiation such as UV light or an electron beam. The markets for such coatings, because of their rapid curing at ambient temperature, low energy requirement, and solvent-less composition, have been steadily grow­ing and expanding in […]

All the major ingredients, including resins, of powder coatings are solid powders. The ingredients are mixed and then homogenized in a heated extruder (a process called melt kneading). The extruded product is cooled, crushed and milled, sieved and classified. The resin must melt at a predetermined temperature to effect proper mixing and pigment dispersion. In […]

In general, high-solid resins are resin solutions in organic solvents that are required to be supplied at >70 % solid content at mana­geable viscosities. Since viscosity of resin solutions is very depen­dent on their MW, high-solid resins are designed with low MW. In order to obtain the desirable properties of coatings with these low MW […]

As discussed above, there are many technical and environmental pollution related issues in using solventbased acrylics, especially solventbased TPAs. This has led to the development of waterborne acrylic resins and coating systems. Commercial waterborne acrylic resins are supplied as dispersions in water. Generally, a polymer dispersion is a two-phase system consisting of spherical polymer particles, […]

Thermosetting acrylic resins contain reactive functional groups that can be used to obtain cross-linked films after application. These resins are prepared by a very similar process to that used for TPAs by using functional acrylic monomer as one of the co-monomers. Typical functional monomers used for such resins are 2-hydroxye- thyl acrylate for — OH […]

TPAs are high MW acrylic copolymers supplied in organic solvents. These copolymers are typically prepared from monomers such as methyl methacrylate, styrene, or n-butyl acrylate. The selection of solvent is dictated by solubility of the resin, solution viscosity, evaporation rate, type of final coating for which it will be used, and cost. TPAs are generally […]

The term solution acrylics refers to acrylic resins prepared by chain-growth polymerization using a solutionbased polymerization process. Here, acrylic monomers and initiators are slowly added to an organic solvent and polymerization is carried out at a predeter­mined temperature and inert atmosphere with efficient stirring. Both monomers and the polymer formed are miscible in the selected […]