The alkyd resin used in alkyd resin coatings (Code C) is formed by esterification and polycondensation of polyhydric alcohols, polyacids and fatty acids. There are many types of alkyd resins, and alkyd resin coatings of many models and specifications have been produced. It is a coating based on alkyd resin as the main film-forming substance.
There are three types of alkyd resins for coatings: non-drying oils (such as castor oil, coconut oil and synthetic fatty acids, etc.) modified alkyd resins; drying oils (such as dehydrated castor oil, linseed oil, soybean oil, catalpa oil, tung oil, etc. etc.) modified alkyd resin; oil-free alkyd resin, such as neopentyl glycol alkyd resin, allyl ether alkyd resin.
The properties of alkyd resin coatings are related to the type of modified vegetable oil and the degree of oiliness. The oil degree is generally divided into short oil (30%~45% oil content), medium oil (46%~55% oil content) and long oil (56%~70% oil content). The influence of different oil levels on the properties of oil-modified alkyd resin coatings is shown in the table. Alkyd resin paint film is full and bright, with good mechanical strength, good weather resistance and gloss retention, strong adhesion, good solvent resistance and durability, fast drying, low price, good construction performance, but poor water resistance. Alkyd paints can be air-dried or oven-dried at low temperature. It is a popular product widely used in CHINA, and is widely used in light industry, wood, vehicles, ships, bridges, mechanical and electrical products and construction industries.
At present, alkyd resins account for more than 40% of all foreign synthetic resins used in coatings. In domestic coatings, the production of alkyd resin coatings plus alkyd resin-containing amino, nitro, epoxy resin paints and other coatings accounts for about 40% of the total output of coatings, so alkyd resins and their coatings play an important role in the coatings industry. status.
