Synthesis And Properties Study Of A Waterproof Waterborne Polyurethane Textile Coating Agent

Waterborne polyurethane is a materials which has a good comprehensive performance.the fabric will have good softness,abrasion resistance and other properties by use the Waterborne polyurethane as fabric coating agent.Due to the introduction of hydrophilic chain extenders in waterborne polyurethanes,as a fabric coating agent,the coating is easily swallowed by water and the application is limited.Therefore,a waterborne polyurethane fabric coating agent having a waterproof function synthesized has important significance and application value.The synthesis of water-based polyurethane can be divided into two categories,one for the polyether-type water-based polyurethane,the other for the polyester-type water-based polyurethane.Polyether WPU has good flexibility and low temperature performance,it can still maintain a good feels at very low temperatures,but the heat and light resistance is poor,the tensile strength is not high.Polyester WPU has good mechanical properties and film-forming properties,but the ester groups are easy to hydrolyze and poor in water resistance.Both types of polyurethane have significant advantages and disadvantages,so this subject make these two types of polyurethane compound purposed to achieve advantages and disadvantages complement each other.In this paper,the effects of the ratio of PCDL to PTMG,the total R value,the Initial R value,DMPA and neutralization on the properties of WPU and its coated fabric were investigated by using IPDI as hard segment,PCDL and PTMG as soft segments.It was found that when the ratio of PTMG to PCDL was 3: 1,the Initial R value was 2.5,the total R value was 1.1,the content of DMPA was 5% and the degree of neutralization was 100%,the polyether-polyester mixed waterborne polyurethane has good stability and good film-forming performance.It shows that the particle size of WPU emulsion particles is uniform and moderate,the viscosity of the emulsion is 187 MPa.s,the water absorption is 25.64%,the contact angle of the film is 88.64,the bond strength can reach 0.67 MPa,the tensile strength is 4.36 MPa,and the elongation at break is 486%.it is higher than the general waterproof fabric requirements of the water pressure 5.58 KPa.The effect of the addition amount of hydroxypropyl silicone oil on the WPU emulsion,film-forming property and the waterproofing ability of the coated fabric was studied by using the hydrophobized hydroxypropyl silicone oil to further modify the WPU.It was found that the addition of hydroxypropyl silicone oil could greatly improve the waterproofing ability of the fabric,and with the increase of hydroxypropyl content,the waterproofing ability of fabric coating was enhanced.When the content of hydroxypropyl silicone oil was 3%,the modified WPU has a membrane strength of 4.83 KPa,an elongation at break of 386%,a water contact angle of 104.18° and a bond strength of 0.538 KPa.The water resistance of the coated fabric reaches 24.37 KPa,has good water resistance,and the fabric is smooth and supple.