Synthesis And Application Of Lauric Acid Bismuth In The Polyurethane Prepolymer

Polyurethane(PUR) is a kind of block polymer which is widely used in the world,it has become the world’s five most important synthetic polymer material. PUR can be controlled by changing the length of the block of distribution, changing the molecular weight and degree of crosslinking and other variables, to a big scale on the performance of PUR change. So make use of PUR foam, coatings, adhesives, fiber could be quite useful in the automotive, textiles, packaging, medical, furniture, etc. industries.To further investigate the polyurethane(PUR), this paper first pure 4-4 as a solid diphenyl methane diisocyanate(MDI) with a molecular weight of about 2,000 or so of polyether polyols- polypropylene glycol(PPG) as the main raw material for prepolymerization experiment a reaction to obtain a polyurethane prepolymer. Then the polyurethane prepolymer product structure and performance characterization testing. During the synthesis of the prepolymer by changing different synthesis temperature, testing prepolymer viscosity value-NCO body investigate the calculation of the degree of reaction of the prepolymer optimal synthesis temperature. Finalize the synthesis temperature is 80 ℃, the polyurethane synthesis reaction has fast speed, resulting prepolymers have stable storage stability.In the production of polyurethane, in order to improve the speed of the reaction, the catalyst is generally added an organic amine compound or an organometallic compound catalyst. Organometallic compound catalyst compared to the amine catalyst in catalytic hydroxy and isocyanate-reactive better, more effective. Although organic tin-based catalyst has a strong catalytic effect, use very extensive, but it also has a toxic side effects, can not be applied to medical malpractice PUR product prepared food packaging. Organic bismuth compounds, polyurethane curing have good catalytic effect, and low toxicity, polyurethane catalysts in recent years R & D focus. Current organic bismuth catalysts are major bismuth neodecanoate, bismuth and naphthenic bismuth bitter differences and so on. Bismuth laurate few studies, this paper synthesis of lauric bismuth, explore its curing polyurethane prepolymer catalysis to obtain a non-toxic and efficient new polyurethane catalysts.This paper systematically studied the synthesis conditions lauric bismuth, found that the quality of the optimal concentration of sodium hydroxide saponification is 4%, while in lauric acid synthesis experiment bismuth nitrate and sodium bismuth five lauric appropriate molar ratio range less than or equal to 1: 3.This article was prepared for lauric acid catalytic curing polyurethane bismuth, found alone can catalyze polyurethane curing, but catalytic rate was slightly lower than dibutyl tin catalysts. In order to achieve better catalytic effect at low toxicity, this article will lauric acid bismuth and dibutyl tin 1: 1 complex with a catalytic effect, the composite catalyst reached full use of dibutyl tin catalyst effect. Higher catalyst addition the mechanical properties of polyurethane film, bismuth laurate catalyst can enhance the tensile stress of a polyurethane film, the hardness of some extent. And lauric acid was added bismuth can significantly improve the solvent resistance of polyurethane film, this is better than the traditional organic tin-based catalyst.