Company: Liaoyang Xinyu Chemical Co., Ltd.
Address: No. 29 Vanward two road, Hongwei District, Liaoyang, Liaoning, China.
Abstract: Based on the analysis of imported samples, crystalline epoxy resin was synthesized by a two-step process, and brominated epoxy resin was successfully developed as a special epoxy resin and curing agent suitable for the final crystalline epoxy resin of heavy-duty antiseptic powder. The product has the characteristics of moderate curing speed, good film toughness, cold and hot brominated epoxy resin impact resistance, good corrosion resistance, etc. The main performance indicators reach the level of similar products abroad. In this paper, the preparation principle, process and main factors affecting the properties of crystalline epoxy resin are introduced. Crystalline epoxy resin
In recent years, with the rapid development of national economic construction, the demand for heavy-duty anti-corrosion powder epoxy resin and additives for oil and gas buried pipelines is increasing, and the quality requirements are also increasing. In this respect, the requirements are mainly reflected in the requirements of powder epoxy to have good construction technology (high temperature curing), wear resistance, corrosion resistance, cold and heat shock resistance and long-term stability. Obviously, the epoxy dicyandiamide system powders which have been used for a long time in our country are difficult to meet this requirement either in technicality or in reliability. However, this kind of heavy epoxy anticorrosive powder system has been tested for a long time and has good reliability abroad. Therefore, the anticorrosive powder factories and coating factories have to import epoxy resin and solids from abroad. Chemical agents are processed, or imported epoxy powder directly from abroad for painting. With the start of the West-East Gas Pipeline Project, the demand for high performance and heavy-duty powder coatings will increase rapidly. Businessmen at home and abroad have been optimistic about this huge market, through various ways to strive for a place in this major project.
In order to break the monopoly of foreign epoxy powders in this field, it is necessary to carry out the research on the localization of the fused powdered epoxy resin and its curing agent. On the one hand, it can improve the technical level of heavy-duty epoxy resin and curing agent in China, on the other hand, it can save a lot of foreign exchange for the country and force foreign materials. Make concessions on price and reduce project cost. According to the relevant information provided by the Institute of Powder Coatings and Powder Manufacturers, we have studied the heavy-duty powder epoxy resin and curing agent with reference to some foreign materials on the basis of the analysis of foreign samples.
1. selection of development technology route
1.1 epoxy resin
According to the analysis of infrared and liquid phase spectra of foreign samples, the basic components of foreign epoxy resin samples were determined to be epoxy phenolic resin. Bisphenol A type phenolic aldehyde and phenolic phenolic aldehyde are two kinds of phenolic epoxy resin. From the chemical structure, the resin has high aromatic density, strong corrosion resistance, good film hardness, good wear resistance characteristics. The synthesis method is mainly divided into two steps, one is the synthesis of linear phenolic resin, the other is the synthesis of phenolic epoxy resin.
1.2 curing agent
Previous epoxy antiseptic powders were usually cured with dicyandiamidazole. Although the system had a faster reaction rate, the curing reaction was exothermic and easy to produce internal stress, which made the coating brittle. According to the analysis results of foreign curing agent samples, the main component is the mixture of hydroxyl-terminated polymer and anionic catalytic curing agent. Obviously, this polymer curing agent cured epoxy resin, its film flexibility than dicyandiamide curing system is much better. However, the end groups of macromolecular chains have low reactivity due to the curling of molecular chains, so it is necessary to use anionic catalytic curing agents with high reactivity to adjust the reaction rate. In this way, the synergistic effect of the two guarantees that the powder coatings have good flexibility and faster reaction speed. Polymer hydroxyl-terminated compounds can be hydroxy-terminated polyester or polyether resin, can also be hydroxy-terminated phenolic resin. The latter has higher reactivity than the former, while the former has better toughness than the latter. Based on the above analysis and the results of sample analysis, the composite curing agent of hydroxyl-terminated polyether, phenolic polymer compound and anionic catalytic curing agent was selected as the curing agent of heavy-duty antiseptic powder epoxy.