| The film of epoxy-acrylate hybrid(EA)emulsion has both the advantages of epoxy and polyacrylate,the EA emulsion develops rapidly and has been widely used in many area such as construction projects,electrical appliances and automobile paintings,which accounts for its good mechanical and anti-chemical reagents properties like high strength,high modulus,high gloss,excellent adhesion and great corrosion resistance.In this research,firstly a new epoxy-based polyol has been synthesized by the ring-opening esterification reaction between lauric acid and epoxy,which was used as a modifier to acrylate resin.Then with main raw materials such as acrylic acid(AA),butyl acrylate(BA)and methyl methacrylate(MMA),tripropylene glycol diacrylate(TPGDA)as the inner crosslinking agent,the pre-crosslinked polyacrylate resin containing carboxyl has been prepared by solvent polymerization first.Then the epoxy-modified epoxy-acrylate resin has been synthesized by the second-step ring-opening esterification reaction between carboxyl and the remaining epoxy group of epoxy-based polyol.Then it was dispersed in water after carboxyl groups being neutralized.Thus a new epoxy-acrylate(EA)hybrid emulsion has been obtained.The optimized ring-opening esterification reaction conditions of epoxy resins with different molecular weight has been studied,and also the influence of different epoxy on the aqueous dispersion and the film property.Finally the CYD-011 has been set as the modifier to acrylate resin,and the suitable esterification reaction temperature is 115?,the esterification reaction lasts for 120 min with the proper catalyst dosage which is 0.3%.In the solvent polymerization for EA dispersion,the effect such as the dosage of initiator(AIBN),chain transfer agent(?-SH),cross-linking agent(TPGDA),and epoxy on the performance of emulsion and film have been discussed.It is demonstrated that the emulsion and film show desirable performance when the AIBN dosage is 3.0%,the ?-SH dosage is 2.5%,the TPGDA dosage is 5% and epoxy content is 49%.The influences of the crosslinber TPGDA and epoxy on t he minimum film forming temperature(MFFT)has been studied,the results indicate the emulsion`s MFFT reduces while increasing the content of TPGDA or epoxy.The prepared aqueous dispersion is set as the polyol-component,the influences of different water-soluble isocyanate curing agents on their compatibility and the film properties have been studied.The Bayhydur 2487/1 is selected as the curing agent component because it is more balanced between the mixed state and the film properties.The chemical structures of intermediates and final products in different stage in the process of synthesis,the film properties of hybrid emulsion and two-component products have been tested,characterized and analyzed.The laser particle size analyzer test shows that the epoxy-acrylate hybrid emulsion`s average size is about 90 nm with a narrow size distribution.Fourier transform infrared(FTIR)is used to trace the synthetic process and characterize the structure of epoxy-based polyol,epoxy-acrylate hybrid resin and the two-component curing film.The TG-DSC shows that the two-component curing film has better heat resistance than the epoxy-acrylate emulsion film itself. |
PDF Full Text Request