| Currently,silk fabric suffers from some problems including its poor crease recovery and unacceptable strength after anti-crease finishing.In order to address these problems,the isocyanate terminated polysiloxane finishing agent was designed and prepared for the effective treatment of silk fabric in this study.The raw materials included hydrogen terminated polysiloxane,methylallyl alcohol and MDI(a functional modifier).The polysiloxane segment was used to improve the smoothness and strength of the silk fabric.And the high reactive isocyanate group was applied to enhance the cross-linking interaction between the finishing agent and silk fibers,endowing the finished fabric with a good crease resistance property.However,the finished fabric showed low hydrophilicity due to the strong hydrophobicity of polysiloxane component.Therefore,hydrophilic polyether was introduced into the finishing agent to improve its hydrophilicity.Specifically,the isocyanate terminated polyether modified polysiloxane finishing agent was prepared via the reaction between allyl polyether,hydrogen terminated polysiloxane and MDI.The anti-crease finished silk fabric had good crease resistance and hydrophilicity.The specific research contents and results are shown as follows:Part one:Preparation of isocyanate terminated polysiloxane and its application in anti-crease finishing of silk fabric.Hydroxyalkyl polysiloxane was synthesized by hydrosilylation reaction with hydrogen terminated polysiloxane and methylallyl alcohol as raw materials and chloroplatinic acid as the catalyst.The effects of synthesis conditions on the conversion of double bonds were investigated and the synthesis conditions were optimized.The results indicated that the optimal reaction condition was:the amount of catalyst was 60 ppm,the reaction temperature was 85?,the reaction time was 4 h,the reaction conversion rate was 87.3%.This synthesis condition had good applicability.The product structure was proved to be hydroxyalkyl polysiloxane by the FTIR and ~1H-NMR analysis.The isocyanate terminated polysiloxane was prepared by using hydroxyalkyl polysiloxane as raw material,MDI as functional modifier,and caprolactam as blocking agent.The effects of the blocking reaction temperature and time on the blocking efficiency of-NCO were investigated.The products were characterized by FTIR and GPC.The results showed that the optimal condition of blocking reaction was:n(isocyanate terminated polysiloxane prepolymer):n(caprolactam)was 1:2.4,the blocked temperature was70?,and the blocked time was 3 h.FTIR and GPC confirmed that the product was isocyanate terminated polysiloxane.It was used as finishing agent for the anti-crease finishing of silk fabric.The effect of the molar mass of hydrogen terminated polysiloxane and process parameters(the dosage of finishing agent,curing temperature and curing time)on the crease resistance performance of silk fabric was studied.The finishing conditions were optimized and the properties of finished fabric were evaluated.The results showed that when the molar mass of hydrogen terminated polysiloxane was 1914 g/mol,the fabric obtained the best anti-crease performance.The optimal condition of finishing process was that the dosage of finishing agent was60 g/L,the curing temperature was 150?,and the curing time was 3 min.At the finishing conditions,the dry and wet crease recovery angles of finished silk fabric were 302.6°and 229°,respectively,both the anti-crease property and the washing resistance were the best.The strength damage of finished fabric was ignorable,and the fabric was not yellowed.Compared with epoxy modified polysiloxane,citric acid and glyoxal as anti-crease finishing agent,the silk fabric finished by isocyanate terminated polysiloxane finishing agent had better anti-crease effect and less strength damage.Part two:Preparation of isocyanate terminated polyether modified polysiloxane and its application in anti-crease finishing of silk fabric.Hydroxyl terminated polyether modified polysiloxane was prepared by using hydrogen terminated polysiloxane and allyl polyether as raw materials and chloroplatinic acid as catalyst.The effects of synthesis conditions on the conversion of double bonds were investigated and the conditions were optimized.The structure was characterized by FTIR and ~1H-NMR.The results showed that the optimal reaction condition was:the molar ratio of silicon hydrogen bond to carbon-carbon double bond was 1:1.2,the amount of catalyst was 30 ppm,the reaction temperature was 100?,and the reaction time was 4 h.The conversion rate of the reaction was 88%.On this basis,the isocyanate terminated polyether modified polysiloxane was prepared by hydroxyl terminated polyether modified polysiloxane as raw material,MDI as functional modifier,and caprolactam as blocking agent.It was applied as a finishing agent for the anti-crease finishing of silk fabric.The effects of the molar mass of hydrogen terminated polysiloxane and allyl polyether on the surface activity of finishing agent and the properties of silk fabric were studied.The effects of the dosage of finishing agent,the curing temperature and the curing time on the properties of silk fabric were also studied.The finishing conditions were optimized and the properties of finished fabrics were tested.The results showed that the finishing agent had good surface activity and anti-crease effect when the molar mass of hydrogen terminated polysiloxane was 1321 g/mol and the molar mass of allyl polyether was 400 g/mol.The optimal condition of finishing process was that the dosage of finishing agent was15 g/L,the curing temperature was 140?,and the curing time was 5 min.At the finishing conditions,the finished fabric had good anti-crease effect,the dry crease recovery angle was 308°,the wet crease recovery angle was 214°,and its water-washing resistance was slightly reduced.And the retention rate of breaking strength was 98.3%.The fabric had good hydrophilicity and softness without yellowing.Compared with the isocyanate terminated polysiloxane finishing agent,the finished fabric with this finishing agent had good crease resistance and hydrophilicity.The results showed that the isocyanate terminated polysiloxane finishing agent could improve the anti-crease property of silk fabric and maintain good strength retention of the fabric compared with other anti-crease finishing agents.Compared with isocyanate terminated polysiloxane finishing agent,the isocyanate terminated polyether modified polysiloxane finishing agent could give fabric similar crease resistance,strength retention,good hydrophilicity,hygroscopicity and permeability. |
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