OrganobismuthAdvantages:
1. Safe and environmentally friendly, can replace lead and mercury and those that are being abolished by legislation Tin;
2. It has better hydrolysis resistance and stability, reduces the selectivity of reaction with water, and reduces the side reactions between water and NCO groups in aqueous PU dispersions;
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3. Promote the NCO/OH reaction, avoid NCO side reactions, and reduce the generation of CO2;
4. In a one-component system, add water The shielded amine is liberated instead of promoting the reaction between NCO and water;
5. The combination of bismuth and zinc has a synergistic effect, making the formulation and production more flexible, reducing energy consumption, and increasing profits;
6. Organic bismuth can be used alone or in combination with amines or other organic metal compounds;
Bismuth belongs to Group 15 in the periodic table of elements. It is the most metallic element in the group and the heaviest stable element in the periodic table.
During the hydrolysis aging process, the residues of different metal ions also have an impact on the hydrolysis resistance of polyester resin. Different acetylacetone metal compounds were used as catalysts for the synthesis of polyurethane paint from MDI-polyester. Photoaging studies of the paint film showed that Co, Cu, Ti, and Sn all significantly promoted aging, while Zn, Ni, and Al had almost no effect.
Regarding the moisture resistance of HMDI polyurethane film, the catalyst used in the synthesis process also has an impact on this. Although aliphatic polyurethane resins of weak solvent systems have been used in China for many years, related problems have still not been solved, and research work is still a hot topic in the industry. The storage stability of polyurethane resin is one of the factors for evaluating the performance of synthetic leather.
Catalysts such as T9, Nd, Ce, Bi, Zn, and T12 can effectively catalyze the synthesis of aliphatic isocyanates with hydroxyl and amine groups in weak solvent systems using TOL, IPA, and IBA as solvents. Controlled polymerization to produce polyurethane resin with a viscosity of 40~50 Pa·s. Zr has a strong pro-degradation effect, causing the resin viscosity to drop rapidly, while Ni has a strong pro-gelling effect, making the synthesis difficult to control.
Bismuth compounds have green and safe properties such as low cost, easy handling, low toxicity and low radioactivity. In the past 10 years, both the synthesis of new organobismuth compounds and the research on organobismuth compounds in organic synthesis, catalysts and biomedicine have been at a leading level. Rapid development stage. Organic bismuth products produced in advanced foreign countries have a history of more than 30 years and have been supplied to the European and American markets for many years. These environmentally friendly organobismuth catalysts can be cured at room temperature or under heat, making them an excellent alternative to toxic lead, mercury and tin products.
