News Details
Heavy-duty powder coatings crosslinking agent
2017-3-10 22:09:53
Heavy-duty powder coatings crosslinking agent, using the two footwork, developed into a heavy-duty powder coatings with epoxy resins and crosslinking agent, the main performance indexes reached the level of similar products abroad. Introduces the preparation methods of epoxy resins and crosslinking agent, and discusses the factors affecting its performance.
In recent years, with the rapid development of economic construction in our country, the petroleum and natural gas buried pipeline heavy-duty powder coatings with the demand of epoxy resins and crosslinking agent is more and more big, the quality requirements more and more is also high.
This demands mainly reflects in: antiseptic powder coating has good workability, high temperature rapid crosslinking), abrasion resistance, anticorrosive, resistance to hot and cold impact, long-term stability, etc.
Based on epoxy resin samples of infrared and liquid chromatogram analysis, determine the basic group is divided into phenolic epoxy resin. The molecular structure of the resin in both the bisphenol A type phenolic composition, type and phenol phenolic composition, is A kind of compound phenolic epoxy resin. This resin has strong anticorrosive, high hardness, good wear resistance. The synthesis method in two steps: the first step is the synthesis of linear phenolic resin, the second step is the synthesis of phenolic epoxy resin.
The synthesis of linear phenolic resin. The phenol formaldehyde into the reaction kettle, bisphenol A, and stirring up dissolved, catalyst reflux reaction to 90 ℃ in 3 ~ 5 h; Using dilute alkali neutralization termination reaction, suck out the upper water; Several times repeated washing with hot water to neutral, then heating dehydration, above 150 ℃ / 0.095 MPa vacuum after removing a small amount of free phenol, filtering, discharge, a quick linear phenolic resin.
The synthesis of phenolic epoxy resin. Will be the first step in the synthesis of linear phenolic resin and measurement of epoxy chloropropane into the reaction kettle, heat to dissolve, adding catalyst in 80 ~ 90 ℃ the etherification reaction of 5 ~ 6 h; After reaction, cooling, add some solvent dissolution, gradually adding naoh aqueous solution, the closed-loop response.
Chinese name: Diethyl toluene diamine(DETDA)
Diethyltoluenediamine Raw material ：
TDA industrial, Sichuan production
Ethylene (Et) polymer grade, Shanghai production
TEA industrial imports
A reagent grade additives
The closed-loop response and join the residual solvents, stir to dissolve and repeatedly with hot water washing to neutral for many times, to separate the lower water; Removing the solvent with low boiling temperature rise, in 140 ~ 160 ℃ heat 1 ~ 2 h, aneroid out after cooling; Filtering, tabletting, packaging, for a quick phenolic epoxy resin.
The preparation of the crosslinking agent. Previous anticorrosive epoxy powder coating with dicyandiamide - imidazole crosslinking system. Although the system has faster response speed, but crosslinking reaction heat, easy to produce stress, make the film brittle. Analyze the diplomatic agent samples, the main group is divided into end hydroxyl polymer with anionic catalytic crosslinking agent of distribution of material, through the synergy of the two, to ensure that the powder coating has both good flexibility, and has faster response speed.
Polymer end hydroxyl compounds can be end hydroxyl polyester or hydroxyl-terminated polyether resin, can also be a hydroxyl-terminated phenolic resin. The reactivity is higher than the former, and flexibility of the former is better than the latter. According to the above analysis, combined with the sample analysis result, chose the hydroxyl-terminated polyethers, hydroxyl-terminated phenolic resin composite with anionic catalytic crosslinker to crosslinking agent system.
Measurement of glycol (neopentyl glycol, diethylene glycol, polypropylene glycol, etc.), dihydric phenol, hydroquinone and resorcinol, bisphenol A, etc.) and single, double loop oxide into the reaction kettle, heat, stir to dissolve addition polymerization in 90 ~ 130 ℃; When required by the softening point is, cooling, filtering, discharge, a quick hydroxyl-terminated polyether resin.
Hydroxyl-terminated phenolic resin synthetic process is the same as the basic linear phenolic resin. The synthesis of hydroxyl-terminated phenolic resin, hydroxyl-terminated polyether resin in reaction kettle and melting of up to 150 ℃ after being fully melted, join the measurement of anionic catalyst, uniform mixing, filtering, tabletting, packaging.
Copyright: Zhang Jia Gang YaRui Chemical co.,Ltd
Diethyl toluene diamine(DETDA) http://www.yaruichem.com
In recent years, with the rapid development of economic construction in our country, the petroleum and natural gas buried pipeline heavy-duty powder coatings with the demand of epoxy resins and crosslinking agent is more and more big, the quality requirements more and more is also high.
This demands mainly reflects in: antiseptic powder coating has good workability, high temperature rapid crosslinking), abrasion resistance, anticorrosive, resistance to hot and cold impact, long-term stability, etc.
Based on epoxy resin samples of infrared and liquid chromatogram analysis, determine the basic group is divided into phenolic epoxy resin. The molecular structure of the resin in both the bisphenol A type phenolic composition, type and phenol phenolic composition, is A kind of compound phenolic epoxy resin. This resin has strong anticorrosive, high hardness, good wear resistance. The synthesis method in two steps: the first step is the synthesis of linear phenolic resin, the second step is the synthesis of phenolic epoxy resin.
The synthesis of linear phenolic resin. The phenol formaldehyde into the reaction kettle, bisphenol A, and stirring up dissolved, catalyst reflux reaction to 90 ℃ in 3 ~ 5 h; Using dilute alkali neutralization termination reaction, suck out the upper water; Several times repeated washing with hot water to neutral, then heating dehydration, above 150 ℃ / 0.095 MPa vacuum after removing a small amount of free phenol, filtering, discharge, a quick linear phenolic resin.
The synthesis of phenolic epoxy resin. Will be the first step in the synthesis of linear phenolic resin and measurement of epoxy chloropropane into the reaction kettle, heat to dissolve, adding catalyst in 80 ~ 90 ℃ the etherification reaction of 5 ~ 6 h; After reaction, cooling, add some solvent dissolution, gradually adding naoh aqueous solution, the closed-loop response.
Chinese name: Diethyl toluene diamine(DETDA)
Diethyltoluenediamine Raw material ：
TDA industrial, Sichuan production
Ethylene (Et) polymer grade, Shanghai production
TEA industrial imports
A reagent grade additives
The closed-loop response and join the residual solvents, stir to dissolve and repeatedly with hot water washing to neutral for many times, to separate the lower water; Removing the solvent with low boiling temperature rise, in 140 ~ 160 ℃ heat 1 ~ 2 h, aneroid out after cooling; Filtering, tabletting, packaging, for a quick phenolic epoxy resin.
The preparation of the crosslinking agent. Previous anticorrosive epoxy powder coating with dicyandiamide - imidazole crosslinking system. Although the system has faster response speed, but crosslinking reaction heat, easy to produce stress, make the film brittle. Analyze the diplomatic agent samples, the main group is divided into end hydroxyl polymer with anionic catalytic crosslinking agent of distribution of material, through the synergy of the two, to ensure that the powder coating has both good flexibility, and has faster response speed.
Polymer end hydroxyl compounds can be end hydroxyl polyester or hydroxyl-terminated polyether resin, can also be a hydroxyl-terminated phenolic resin. The reactivity is higher than the former, and flexibility of the former is better than the latter. According to the above analysis, combined with the sample analysis result, chose the hydroxyl-terminated polyethers, hydroxyl-terminated phenolic resin composite with anionic catalytic crosslinker to crosslinking agent system.
Measurement of glycol (neopentyl glycol, diethylene glycol, polypropylene glycol, etc.), dihydric phenol, hydroquinone and resorcinol, bisphenol A, etc.) and single, double loop oxide into the reaction kettle, heat, stir to dissolve addition polymerization in 90 ~ 130 ℃; When required by the softening point is, cooling, filtering, discharge, a quick hydroxyl-terminated polyether resin.
Hydroxyl-terminated phenolic resin synthetic process is the same as the basic linear phenolic resin. The synthesis of hydroxyl-terminated phenolic resin, hydroxyl-terminated polyether resin in reaction kettle and melting of up to 150 ℃ after being fully melted, join the measurement of anionic catalyst, uniform mixing, filtering, tabletting, packaging.
Copyright: Zhang Jia Gang YaRui Chemical co.,Ltd
Diethyl toluene diamine(DETDA) http://www.yaruichem.com
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