Introduction and application industry summary of organic bismuth and zinc catalysts

Our company produces organic bismuth, organic zinc and water-based bismuth catalysts, which are mainly used in polyurethane-related industries, such as PU resins, polyurethane runways, coatings, adhesives, elastomers, etc. Water-based bismuth is mainly used for CED coatings and water-based PU release agents. We have been doing this since 2011, and it has been 13 years. The current sales volume in China is about 600 tons/year, accounting for 60-70% of the market share. The more well-known cooperative enterprises are: Wanhua chemical, Huafon chemical, etc. And currently we export about 60 tons to South Korea every year. Organic bismuth is mainly used to catalyze the reaction of isocyanate and polyol or primary amine. It is basically used to replace organic tin in various industries. After all, organic tin is harmful to the human body, and bismuth itself can be used as stomach medicine, so it is very healthy and environmentally friendly. This is a major trend in the future. Our two biggest advantages are: first, there are many cooperative enterprises and the product quality is quite stable; second, the company isn’t big in scale with a team of about 15 people, the operating cost is not high, and the single product sales volume is large, the raw material cost is relatively lower, so the overall product price has a considerable advantage. It can also be simply summarized as: the product is very cost-effective.

The two main products of organic bismuth are: bismuth neodecanoate and bismuth isooctanoate.

The catalytic mechanism of bismuth metal is to reduce the activation energy on the carbonyl group of isocyanate, thereby promoting a better and faster reaction. Therefore, in the polyurethane oil system, it is mainly reflected in reducing the temperature required for the PU reaction, slightly shortening the reaction time, and improving the crosslinking degree to a certain extent.

The two main products of organic zinc are: zinc neodecanoate and zinc isooctanoate. The catalytic activity of zinc is not as good as that of bismuth, but the characteristic of zinc is that it has a delayed catalytic effect, mainly used to replace mercury and lead. When components A and B meet, zinc will not play a catalytic role immediately, but will take effect after 12-15 minutes. This is adapted to industries that require some operating time in the early stage, such as polyurethane elastomers. For example, polyurethane runways must be leveled in the early stage and cannot be cured too quickly. In the later stage, the surface and inside must be dried simultaneously. This requires adjusting the ratio of bismuth and zinc so that they can complete this task together.

The water-based bismuth carrier is modified bismuth lactate, used in CED coatings, reducing the baking temperature and improving the crosslinking degree of the paint film. Compared with DBTO and DOTO, it is more environmentally friendly, more convenient to use because it does not require grinding, and has a lower cost in your company's products. Compared with powdered bismuth, such as bismuth oxide or bismuth hydroxide, it is also more convenient to use, the catalytic efficiency at the organic molecule level is much higher than that of powder, and it can also save costs.

Compared with water-based emulsion, the addition amount is 4-5 thousandths, which can reduce the baking temperature by 10-15 degrees. Or another way to understand it, if the cooling effect is not considered, under the same baking temperature conditions, the cross-linking degree of the paint film can be increased by 30%-40%.

Another current application of water-based bismuth: polyurethane water-based release agent, which is still in the application testing stage. The main function is to promote the cross-linking and curing of the surface of PU products during the demoulding process. Based on the experience I learned from visiting some water-based release agent customers, because there is only a thin layer of release agent in the mold, and our water-based bismuth is only added at about 0.5%, plus the bismuth content of 10.5%, in fact, this thin release agent only contains 0.05% of bismuth element, so the improvement in the demolding effect can be said to be negligible. But at least we have learned from communication with customers that water-based bismuth has no adverse effects on the surface of polyurethane products, such as the generation of pinholes. However, I believe that if it is compared and tested for a long time at the demolding site, it will still have a good effect compared to not adding any catalyst.

We will try to promote our water-based bismuth catalyst in water-based PU coatings and adhesives in the future.

The above is the introduction to several of our main products and some of my experience in several industries. Welcome to your technical exchanges and guidance. If you are interested in any of our products, please feel free to contact us.

E-mail: [email protected]

Tel: +86-18817338241

Mike Zhu