Company: Liaoyang Xinyu Chemical Co., Ltd.
Address: No. 29 Vanward two road, Hongwei District, Liaoyang, Liaoning, China.
The preparation methods of alicyclic epoxy resin and acrylic resin with epoxy group for outdoor powder coatings, the properties of crystalline epoxy resin and its application in powder coatings are introduced. Some opinions and suggestions on the development of epoxy resin for powder coatings are put forward.
With the rapid development of outdoor building materials, household appliances and the increasing number of vehicles, the demand for outdoor coatings products is increasing. Many new problems need to be solved urgently in the coatings industry and raw material manufacturers, both in variety and performance requirements. Powder coatings occupy a considerable proportion in outdoor weathering coatings because of their high efficiency and non-pollution. But at present, the outdoor powder coatings, especially the epoxy powder coatings, are single and difficult to meet the requirements. Therefore, the development of new outdoor epoxy powder coatings, especially new epoxy resins, will be of great significance. In this paper, some new kinds of epoxy resin for outdoor powder coatings are introduced based on the recent data at home and abroad, and some suggestions for the development of the new varieties are put forward.
Epoxy resin used for outdoor powder coatings has high manufacturing cost because of its special structure. At present, the outdoor epoxy resin is basically triglycidyl cyanate, or TGIC. As a curing agent of carboxyl terminated saturated polyester resin, TGIC has been used for many years because of its good weather resistance, corrosion resistance and temperature resistance. However, the toxicity and irritation of TGIC have aroused a lot of controversy. The use of hydroxyalkylamide and glycerol urea as curing agents of polyester resin can reduce the toxicity, but there are still some problems such as volatile release, unstable hydrolysis and unstable storage. Over the years, countries around the world are actively exploring, hoping to find better varieties. Among these possible substitutes, epoxy resins with weather-resistant alicyclic and aliphatic groups will be ideal substitutes. The following are some of the varieties to be introduced, hoping to attract the attention of domestic counterparts, to promote the development of outdoor powder coatings in China with epoxy resin.
1. aliphatic epoxy resin
The alicyclic epoxy resins can be divided into traditional alicyclic epoxy resins with epicyclic epoxy group and alicyclic epoxy resins with glycidyl group according to their structure and preparation process.
1.1 traditional alicyclic epoxy resin
The traditional alicyclic epoxy resin was developed earlier in China. It was mainly produced by Tianjin Synthetic Materials Research Institute and Tianjin Jindong Chemical Plant since the 1950s. The yield is very small and the price is very high. It is mainly for military use. This kind of epoxy resin has low reactivity with conventional curing agent and high brittleness of cured material. There is no report on this kind of epoxy resin used in powder coatings at home. There are patent applications abroad in recent years.
Rickert; Christoph "2" uses trisorbitol, mannitol, pentaerythritol and 1,2,5,6 tetrahydrobenzaldehyde (which can be prepared by the addition of butadiene and acrolein) to perform aldol condensation catalyzed by p-toluene sulfonic acid or trimerization of 1,2,5,6 tetrahydrobenzaldehyde to obtain intermediate, which is then used in peracetic acid with anhydrous solution. Several kinds of aliphatic epoxy resins which can be used in powder coatings are prepared by epoxidation under the action of sodium acetate.