Study On Preparation And Modifications Of Carboxylic Acid Type Waterborne Polyurethane

Waterborne polyurethane(WPU) with the advantage of non-toxicity, low burning point and environmental,has been widely used in the development of social economy.However,Waterborne polyurethane also has many disadvantage,for example,low solid content,poor strength of membrane,poor water and solvent resistance. The purpose of this subject is preparing Water polyurethane with a good water resistance,mechanical properties and membrane,it will be used in textile finishing.This project was prepared carboxylic acid type waterborne polyurethane with TDI(toluene diisocynate) and polyester polyol JW2544 which molecular weight is2589,DMPA(dimethylolpropionic acid) called small molecule chain extender,TEA(triethylamine) called neutralizing agent;and the use of modifier KH-550(γ-aminopropyl triethoxy silane) take siloxane groups into waterborne polyurethane system,for heat resistance and water resistance,low temperature flexibility etc.of waterborne polyurethane materials.Analysis to determine the optimal process conditions of Waterborne Polyurethane.The subject discusses the effect of factors on the performance of carboxylic acid type waterborne polyurethane material.The R value, the dosage of DMPA, the degree of neutralization on polyurethane emulsion to affect the appearance, the mechanical properties of membrane, membrane absorption rate as analyzed, and determined the best value.Process ultimately is determined in the R value of2.5, pre-polymerization reaction to obtain a better pre-polymerization system at a temperature of 75 ℃ and 100 min, the content of DMPA was 5%, 80 degrees in the chain extension reaction of 90 min, and then through the neutralization reaction, neutralization degree is 100%, polyurethane emulsion finally adding DI water emulsion to obtain optimal performance.The optimum technology of modified emulsion:modifier KH-550 dosage is5%,the temperature at 45℃ of 60 min,can obtain the excellent performance of the modified waterborne polyurethane.Carboxylic acid type waterborne polyurethane and modified emulsion was used as textile functional finishing agent for fabric.This project makes a three application research:1.As the crosslinking agent in order to improve two kinds of pigment printing,cotton and polyester cotton fabric on the color fastness to rubbing grade.2.As theanti crease finishing agent is applied to cotton fabric.3.As the anti pilling finishing agent was used for cotton knitted fabric,to improve the anti pilling grade.Moreover,we analyzed three kinds of finishing process influence on finishing results.By FT-IR analysis we confirmed the preparation of polymer which containing urethane bond characteristic group of polyurethane,the modified polymer containing Si-O-Si groups,the synthesis of carboxylic acid type and modification of waterborne polyurethane was successful.TG analysis showed that the heat resistance of Silicone coupling agent modified waterborne polyurethane was superior to that of the unmodified emulsion.SEM pictures reflect carboxylic acid type waterborne polyurethane emulsion was succeed in crosslinking agent among the fiber, to achieve the purpose of finishing.