Study On Synthesis Of Waterborne Polyaspartic Ester Dispersion

Polyaspartic ester polyurea is the third generation of new polyurea system after aromatic polyurea and aliphatic polyurea.It is a kind of new aliphatic polyurea product with slow reaction and high performance.It has excellent comprehensive properties and can be used in many fields such as waterproof,anti-corrosion,floor and wood paint.At present,there are few researches on the waterborne technology of polyaspartic ester,and all of them are patents.Therefore,it is of great significance to study the waterborne technology of polyaspartic ester.Polyaspartic esters were prepared by using maleate esters and primary amine compounds as raw materials,and characterization tests(FT-IR,TG,DSC)were carried out.The effects of the variation of primary amine compounds and maleate esters on polyaspartic ester were discussed,and the effect of catalyst on the percent conversion of polyaspartic ester was studied.The experimental results showed that:Polyaspartic ester PAE(a)synthesized from diethyl maleate and 4,4’-diaminodicyclohexyl methane was a fast-drying system with high reactivity;Polyaspartic ester PAE(b)synthesized from diethyl maleate and 3,3’-dimethyl-4,4’-diaminodicyclohexyl methane was a slow-drying system with low reactivity;The pendant groups of maleate esters had a great influence on the coating properties of polyaspartic ester polyurea.Polyaspartic ester prepared from dimethyl maleate had poor storage stability,and polyaspartic ester prepared from dibutyl maleate had soft film,while the paint film properties of polyaspartic ester prepared from diethyl maleate was the best;The catalyst could effectively shorten the reaction synthesis time.Then using the prepared polyaspartic ester as raw material,three different synthetic routes were adopted to prepare waterborne polyaspartic ester dispersions.Characterization tests(FT-IR,TG,DSC,TEM)and performance tests were carried out on the prepared waterborne polyaspartic ester dispersions.The effects of the amount of solvent DMM,the molecular weight of polyether amine,the type of diisocyanate and the ratio of PAE(a)/PAE(b)(molar ratio)on the state and properties of waterborne polyaspartic ester dispersion were discussed.The experimental results showed that only the waterborne polyaspartic ester dispersion prepared from polyether amine,diisocyanate and polyaspartic ester resins was stable.When the amount of solvent DMM was 5%,the molecular weight of polyether amine was 1000,the diisocyanate was isophorone diisocyanate(IPDI),and the molar ratio of PAE(a)/PAE(b)was 4,the waterborne polyaspartic ester dispersion was in a stable state without delamination in six months,and the paint film properties were the best.The prepared waterborne polyaspartic ester dispersion was applied to wood paint coatings,and the effects of waterborne isocyanate curing agent and two-component distribution ratio on the properties of wood paint films were discussed.The experimental results were as follows: when Shiquanxing D-100 waterborne isocyanate curing agent was selected and the ratio of n(-NCO)/n(-NH)was 1.3,the film had smooth appearance,high gloss,high hardness,good impact resistance and strong adhesion,and it meets the standards for the use of wood paint.