The Synthesis And Performance Of Alkylhydroxyl-containing Silicone Modified Waterborne Polyurethane

In order to develop a silicone modified polyurethane latex for leather, a series of alkylhydroxyl-containing silicone with active hydrogen was synthesized, characterized, and used to prepare the alkylhydroxyl-containing silicone modified polyurethane latex;the performance of alkylhydroxyl-containing silicone modified waterbome polyurethane on leather surface was investigated.The alkylhydroxyl-containing silicone with various structure and polymerization degree was prepared based on D4, allylic polyether. Fourier transform infrared and H-NMR were used to identify the structure of the silicone.We focused on the preparation and characterization of various composition alkylhydroxyl-containing silicone modified polyurethane latex. The key factors that affected the stability of emulsion were investigated, finding the proper NCO/OH ratio, hydrophilic group and acetone quantity ratio. We investigated the influence of alkylhydroxyl-containing silicone on the properties of waterbome polyurethane (like stability, rheological property). Especially the influence of the quantity ratio of silicone, and different kinds of silicone on the film's water and solvent resistance of modified waterbome polyurethane.Some analytical methods were used, such as transmission electron microscopy, laser particle size, rheological dynamics, contact angle and scanning electron microscope analyzer. Through these methods, the microcosmic and macroscopical characters of polyurethane emulsion and films were obtained.The experimental results showed that when the quality ratio of silicone changed from 0 to 6%, the emulsion remained stable and the rheological dynamics did not change. The surface of unmodified polyurethane film was generally smooth, but the surface of modified waterbome polyurethane film was covered with large openings, when the quality ratio of silicone went to 2%, the water contact angle of modified waterbome polyurethane increased from 82° to 103°. It also found that the quantityratio of silicone went to 2%, the water absorbing capacity of the film reduced about 50 percent, the silicone modified waterborne polyurethane improved the water resistance of film. In the same time, we found that PDMS-2, PDMS-3 modified film had better toluene resistance than unmodified film, but PDMS-1 modified film did not have influence on the toluene resistance.Furthermore, the latex on the leather was investigated. It has been found that the leather possessed better water proof, fastness to rubbing of leather increased from 3 to 5 grade when the modified emulsion was used on leather.