Preparation And Application Of A Siloxane Modified Aqueous Polyurethane Anti-felting Agent For Wool

In this thesis, a series of water-borne polyurethanes was successfullyprepared with isophorone diisocyanate(IPDI), 2,4-toluene diisocyanate(TDI)and poly (propylene oxide triols and diols ) with different molecular weights,and the modified with polysiloxanes. A novel bisulfite adduct of siloxanemodified polyurethane aqueous system was designed and synthesized withhydroxyl end-grouped polysiloxane and IPDI for shrink-resist treatment ofwool. The study consisted of three main parts:â…°) the synthesis of thepolyurethane aqueous system and discussion of their phase inversion andstability,â…±) the preparation of siloxane modified water-born polyurethane andtheir blockingreaction,â…²)The effects of the treatment on the dyeing prepertyof wool fabric and on the color of dyed wool.The introduction of polysiloxane segment into IPDI-based polyurethaneled to a new product with satisfactory shrink resistance and good handle,named Simorene Pro. Every factor of the prepolymerization of IPDI, TDI withpolyols was examined. The mechanism of reaction between the IPDI andhydroxyl group ended polysiloxane was proposed and the dispersion behaver ofthe prepolymer in the system was discussed. The sodium bisulfite blockingreaction of the prepolymer was investigated. the behaver of the phaseinversion of bisulfite adduct of siloxane modified polyurethane was alsostudied. The results showed that the dispersion included the phase dismissingof aggregate of hydrophilic segments and aggregation of hydrophobic segments.According to the change of viscosity and conductivity, the point of phaseinversion increased with increase of molecular weight of polyols. The ratio ofsolvent to water and amounts of sodium bisulfite and water also affected thebehaver of phase inversion. The results of study provided the theories basis ofsynthesis of water born polyurethane. The appearance, the dispersion character, the viscosity, the stability at highand low temperature, the stability to pH, the tability to electrolyte of SimorenePro prepared were investigated. The results showed that the Simorene Proexhibited good stabilities in all conditions, it could be stored at 50℃for aperiod as long as 12 months, it could be used as a mixture with 10% NaClsolution at any concentration, it could also be used when the pH was lower than9.By means of investigation of effects of the pH value, the temperature, thekind and amount of alkali in the finishing bath on area shrinkage of the treatedfabric, the process of finishing were discussed systematically. It was applied forwool fabrics with NaHCO₃ as alkali; pH 10.5, at the room temperature, the pickup was 65%, for shrink-resist treatment by traditional pad-dry-cure process.The treated fabric possessed good shrinking-resistance and handle withpermanent effect.The measurement and subjective evaluation showed that theintroduction of polysiloxanes into PU resin can also give good anti-feltingeffect. While the ultra-thin fih-n over the surface of wool fiber was fort-ned tominimize the Different Frictional Effect of the wool fiber. The introduction ofpolysilicone segments into polyurethane aqueous system could significantlyimprove the handle of treated fabric.A comparison of Simorene Pro with the other treatment agents availablefrom the market was arranged, the results also indicated that the polysiloxanemodified water-born polyurethane could endow the wool fabric with shrinkresistant property that meet the standard of IWS TM-31 and better handle anddrape-ability than the others, the results also showed that the strength and othermechanical properties of fabric were almost unchanged by treatment withSimorene Pro.