Preparation And Characterization Of Aqueous Epoxy Dispersion And Its Aqueous Curing Agent Based On Sulphonate

Firstly, a new type of aqueous epoxy dispersion based on sulphonate was prepared byusing amine sodium sulphonate （IPDA-SO₃Na） as a hydrophilic monomer, D-230as a chainextender and bisphenol-Aepoxy resins （E-44）. Effects of reaction temperature and time of thereaction between E-44and IPDA-SO₃Na, IPDA-SO₃Na content, R value [E-44/（D-230+IPDA-SO₃Na）, mol/mol] on the average particle size and stability of dispersion were studied,also the structure of the product was characterized by FT-IR. The results show that with theincrease content of IPDA-SO₃Na, the average particle size decreases, the particle sizedistribution narrows and the viscosity increases. In addition, the average particle sizeincreases, the particle size distribution becomes broader and the viscosity decreases when Rvalue increases. In the condition of the content of IPDA-SO₃Na is14mmol/100epoxy resinand R value is1.8, aqueous epoxy dispersion based on sulphonate was prepared with solidcontent43%，theoretic epoxy value0.64mmol·g-1, the particle size275nm, the viscosity265mPa·s as well as ζ potential-42mV. The dispersion in the centrifuge has no delaminationwith3000rpm rotation and can be stored under normal temperature for six months. Thestructure of the modified epoxy resin analyzed by FT-IR is just the designed form. TEMmicrographs show that the sizes of the spherical shape pellet particles are nonuniform with amultivariate distribution.Secondly, a new type aqueous epoxy curing agent based on sulphonate was synthesizedby series of processes including the following steps: first, diethylene triamine was end-cappedwith single epoxide compounds such as n-Butyl Glycidyl Ether, Benzyl Glycidyl Ether;second, DETA-SO₃Na was mixed with the products from the above process; third, E-51wasused to react with the mixture. The I type two-component aqueous epoxy coating wasproduced by the synthesized aqueous epoxy curing agent based on sulphonate and epoxy resinE-51. Reaction raw materials and process conditions were determined and different rawmaterial ratios on I type two-component aqueous epoxy coating were studied, also thestructure of the synthesized curing agent was characterized by FT-IR. The result shows thatwhen formula follows [n（DETA-n-BGE）+n（DETA-BGE）+n（DETA-SO₃Na）]:n（E-51）=2:1,wt%（DETA-SO₃Na）=5.6%, n（n-BGE）:n（BGE）=3:2, the two-component coating mentionedabove gets small particle size and good stability, providing the cured film with good physicalproperty: pencil hardness reaches2H, flexibility1mm, impact resistance55kg·cm, watertolerance180h. Finally, the III type two-component aqueous epoxy coating in comparison with the I typeabout the pot life and water tolerance, was prepared with the home-made aqueous epoxydispersion based on sulphonate and aqueous epoxy curing agent based on sulphonate. Theratio of dispersion and curing agent on the coating performance was investigated and TG wasused to analyze the thermal properties of the film.