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| Preparation of water-borne polyurethane dispersion modified by epoxy resin |
1. School of Chemical and Energy Engineering, South China University of Technology, Guangzhou, Guangdong 510640, China; 2. Guangdong Carpoly Chemical Co. , Ltd, Jiangmen, Guangdong 529085, China）
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Abstract The water-borne polyurethane dispersion was synthesized by using epoxy resin as macro molecular chain extender. When the reaction temperature is between 70 - 75 ℃, less open-ring reactions occur between epoxy radical and NCO radical. Conversion rate of NCO group is up to 100%. The viscosity reaches 1.5 Pa · s, the tensile strength is 10 MPa and the elongation is 450%. When the epoxy value is between 0.27 and 1.16 mol/g, and the using level is between 4% -6% , good appearance, good mechanic performance and good stability are obtained. After the adding of epoxy resin, when the using level of hydrophilic chain extender DMPA is at 8% , stable dispersion is obtained. When the triethylene amine （TEA） is used as neutralization agent, a whitening and coarse dispersion is obtained; when the sodium hydroxide is used, a semi-transparent and fine dispersion is obtained; the result of using ammonia is in between.
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2008, Vol. 29 
