Development And Application Of High Efficiency Emulsifier For Preparation Of Heavy Anticorrosive And Environmental Protection Waterborne Coating Resin

In recent years,water-based epoxy resin anti-corrosion coating is widely used in the field of anti-corrosion by virtue of its low VOC emission and transportation safety.Epoxy resin is a lipophilic and hydrophobic substance,so water-based epoxy resin is the focus of preparing water-based epoxy anti-corrosion coatings.At present,the main means of waterborne epoxy resin is emulsifier emulsification method.So the key to prepare a waterborne epoxy coating with superior anti-corrosion performance is to develop a high-performance emulsifier.It is reported that the problem of small-molecule emulsifier is that the emulsifier molecules are easy to migrate and thus gather to the surface of the epoxy paint film,reducing the anti-corrosion performance of the epoxy paint film;the problem of large-molecule emulsifier is the high molecular weight of the emulsifier,the viscosity of the prepared emulsion is too high,which is not conducive to construction operations.To solve the above series of problems,an amphiphilic hyperbranched polymer is proposed to be used as a new epoxy emulsifier for the preparation of waterborne epoxy resin anti-corrosion coatings.The sphere-like structure of this hyperbranched emulsifier can reduce the viscosity of the system;the multifunctional group feature can improve the emulsification efficiency of this emulsifier.Therefore,the waterborne epoxy coating prepared by this emulsifier not only has excellent heavy anti-corrosion properties,but also has low system viscosity and easy construction work.To address the emulsification performance of the emulsifier,this thesis proposes to develop a hyperbranched emulsifier for the preparation of heavy-duty anti-corrosion waterborne coatings,the main work of which is as follows:1.Polyethylene glycol monomethyl ether p-toluenesulfonate(m PEG-Ts)was prepared by activating polyethylene glycol monomethyl ether(m PEG)with p-toluenesulfonyl chloride(Ts Cl).HPEI-m PEG was prepared by nucleophilic substitution reaction of m PEG-Ts with hyperbranched polyethyleneimine(HPEI).The prepared HPEI-m PEG and the lipophilic group epoxypropyl phenyl ether(PGE)were used to prepare hyperbranched epoxy emulsifier HPEI-m PEG-PGE by ring-opening reaction of epoxy groups.Successful preparation of HPEI-m PEG-PGE was demonstrated by ~1H-NMR and FTIR.The HLB and CMC of this emulsifier were determined by emulsification method and surface tension meter.Waterborne epoxy emulsions were prepared using this emulsifier and epoxy resin E44 by the reverse rotation method.The effects of rotation speed,temperature,time,emulsifier ratio and solid content on the emulsion properties were investigated and the optimal process formulation for the preparation of the emulsion was analyzed.The emulsion prepared with optimal process parameters had an epoxy value of0.103,epoxy equivalent of 963 g/mol,viscosity of 1103 m Pa·s,particle size of 193～320nm,and mechanical stability of grade 5,and could be stored stably for two months.The water-based epoxy anti-corrosion coating is prepared by compounding the prepared emulsion with the curing agent T31.When the molar ratio of the epoxy equivalent of the emulsion to the active hydrogen equivalent of the curing agent is about 1:1,the performance of the paint film was best.The water resistance,acid resistance,alkali resistance,adhesion and hardness of the paint film were evaluated,and the test results were far better than the national standard.2.Hyperbranched epoxy emulsifier HPEI-m PEG-DGEBA was prepared by using HPEI-m PEG and lipophilic group bisphenol The HLB and CMC of the emulsifier were determined and the optimum conditions for the preparation of aqueous epoxy emulsions were investigated,with an epoxy value of 0.113,an epoxy equivalent of 884 g/mol,a viscosity of 1245 m Pa·s,a particle size of 232～322 nm,a mechanical stability of 5 and a storage stability of three months.The results of water resistance,acid resistance,alkali resistance,adhesion and hardness of the prepared paint films exceed the national standard.3.Hyperbranched epoxy emulsifier HPEI-m PEG-E44 was prepared using HPEI-m PEG and hydrophobic group bisphenol A type epoxy resin E44 using ring opening reaction of epoxy groups.Successful preparation of HPEI-m PEG-E44 was demonstrated by ~1H-NMR and FTIR.The HLB and CMC of this emulsifier were determined by emulsification method and surface tension meter.The emulsion prepared with the optimal formulation had an epoxy value of 0.101,epoxy equivalent of 991 g/mol,viscosity of1315 m Pa·s,particle size of 217～289 nm,mechanical stability class 5,and stable storage for 5 months.The performance of emulsions prepared by different emulsifiers of HPEI-m PEG-PGE,HPEI-m PEG-DGEBA,HPEI-m PEG-E44,SDS,SDS+Span-80,and OP-10was compared,and only the emulsion prepared by HPEI-m PEG-E44 emulsifier had the best stability.The prepared emulsions were compounded with curing agent T31 to prepare waterborne epoxy anti-corrosion coatings.The water resistance,acid resistance,alkali resistance adhesion and hardness of the paint film were evaluated,and the results were far better than the national standard.