The Synthesis And Application Of Waterborne Polyurethane Fixing Agent

There must be a level of colour fastness to the soaping, washing and friction after tintaging the deep color fabrics with reactive dyeing, in order to reach the aim, usually, there is a fixation treatment. The traditional fixing agent which contains free formaldehyde has already fall into disuse, and emerge the new-style aldehyde fixing agent. For the past few years, the functional groups have been introduced into the waterborne polyurethane, which had been used in the textile finishing, and it has reached a great effects.Using the self-emulsify measure, the non-reactive waterborne polyurethane fixing agent and reactive polyurethane fixing agent were manufactured with Toluene diisocyanate (TDI), isophorone diisocyanate (IPDI), N-methyl diethanolamine(MDEA), polyethylene glycol(PEG), polypropylene glycol(PPG), sodium sulfite and sodium hydrosulfite the raw material and N,N-dimethy formamide the solvent, and tested their with FT-IR.Not only the selection and matching of polyether and the prepolymerizatio reaction temperature and time but also the chain extension temperature and time were discussed in the synthesis. Also the influence of R on the fixing agent property and fixing performance was discussed. And the best synthetic technology of producing the non-reactive fixing agent was discovered, which is as follows:the proper prepolymerization reaction time of PEG1000and IPDI is120mins at the temperature of55-60℃with the R2.1, and then adds to PPG1000the amount of which is50%of PEG1000with the prepolyerization reaction time is90mins at the temperature of40-50℃.And then the non-reactive fixing agent through self-emulsify method eliminating the solvent was got by using the reduced pressure distillation. The best synthetic technology of producing the reactive fixing agent is as follows:the prepolymerization reaction time of PEG1000and IPDI is120mins with the R2.1at the temperature of55-60℃. Then the non-reacted-NCO groups by NaHSCO3with hydrophilic chain extender the dosage of which is1/2of PEG1000, and the value of n(Na2SO3)/n(NaHSO3) and n(NaHSO3)/n(—NCO) are0.2and1.3respectively were blocked, At last, the reactive fixing agent by emulsifying60mins in the ice-bath with aqua destillata as additives. The non-reactive and reactive fixing agent were tested with FT-IR confirming its polymer content, viscosity and stability. The results show that the synthetic non-reactive and reactive fixing agents are both polyether waterborne polyurethane which have good stability with the polymer content27.8%and25.6%and viscosity380mPa·s and260mPa·s.Applying the non-reactive and active fixing agent together to the purified cotton with the padding method, the discussed factors that affect the whole process and confirm, the best color fixing process of dyed cotton fabric is the following:the colored cotton fabricsâ†'two dippings and two rollings (the dosage of the color fixing agent60g/L, pH controlled6-7, the pick-up80%)â†'dryingâ†'curing (150℃×3min).There is a great improvement of colour fastness of the colored cotton fabrics to water and rubbing, especially the fastness to wet rubbing which can enhance0.5-1.5degree. And the effect of the synthetic waterborne polyurethane which has little influent on the colored light are as good as the available fixing agent, and the effect is within the acceptable range.