| Waterborne polyurethane (WPU) is just water-based polyurethane, is the general term that contains many of the repeat carbamate group (-NHCOO-) polymers in the molecular structure, are generally derived from the interactions of polyamine or polyol compounds (polyether polyols or polyester polyols) and the dual or multiple organic isocyanate,is a new type of environmental protection formaldehyde-free resin finishing agent. the fabric that are finished by water-based polyurethane can be formed on the surface of the fiber cross-network-like film, reduced inter-fiber slippage, and resin can evenly cross-linked cohesion in the yarn surface, so that adhesion the fiber to the yarn end, the yarn hairiness and reduce static electricity, friction from the ball hard, and the structure with a hydrophilic group and have a certain hydrophilicity.The topic chooses isophorone diisobutyl hydrogen mofetil (IPDI),isophorone (IP), melamine and capping agents such as sodium bisulfite as the main raw material, through step-by-step prepolymer synthesis of waterborne polyurethane, through the synthesis of pre-dimer and closure phases of client and emulsified prepolymer synthetic latex, and their performance and product applications were studied. In the reaction process of polyurethane synthesis, the hydrogen diisobutyl mofetil in the isocyanate (-NCO) group has a higher lively, and easily with water, hydroxyl (-OH) reaction and generate by-products, thus the response of preparing the waterborne polyurethane must be terminated in the saturated sodium bisulfite in aqueous solution, as the reaction is related to two-phase response, in the synthesis reaction process must be strictly controlled conditions of a good response. Solution properties of polyurethane study found, IPDI waterborne polyurethane-based fabric finishing in the anti-yellowing degeneration was superior to other aliphatic diisocyanate. After synthetic polyurethane finishing agent, and a large number of applications for their finishing experiment and determination of the fabric of the elastic recovery angle, tear strength, breaking strength, anti-pilling indicators, such as experiments to determine the impact of technology conditions, and then the process in determining the conditions to deal with cotton fabric and polyurethane, the results can be found by using synthetic polyurethane finishing agent can achieve the desired results.The experimental results show that self-made water-based aliphatic polyurethane has a good effect of anti-pilling on the cotton fabric, the best synthesis conditions of its prepolymer and the closure were as follows: prepolymer reaction temperature is 80 ~ 90℃, reaction time about 4 ~ 5 hours, with isopropyl alcohol as the solvent, NaHSO3 for capping agent, Na2SO3 to promote the agent, at a temperature of 20℃after 2h reaction and adjust the pH to 3 to 5 may have a higher rate of closed-end and the better stability's waterborne polyurethane. testing and analysising the synthetic aliphatic waterborne polyurethane through the infrared spectra, in the 2275 ~ 2250cm-1 bands were not obvious within the absorption peak can be proved to achieve the desired goal. Then, finishing the fabric with the synthesis of aliphatic waterborne polyurethane, draw the optimum conditions: pH value of liquid finishing 8.0, dosage of 80g/L, curing temperature of 150℃, curing time of 90s,and using padding finishing process on the pure cotton knitted fabric. Above the optimum use of the fabric after finishing, whiteness, breaking strength, tear strength, recovery angle and flatness are satisfied with the performance of the combined effect, in which the fabric of the tear strength increased by 20%, anti-pilling fabric pilling grade 1.5 grade, to improve recovery angle 30℃, smoothness and brightness have improved.
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