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What is the purpose of classification of polyurethane catalysts?
Edit:Nantong Yutai Chemical Products Co., Ltd.   UpDate:2019-10-11

Polyurethane retardation catalysts are very specific catalyst types in polyurethane catalysts. This catalyst provides the catalytic activity required to cure the polyurethane while extending the life of the product and providing more operating time for the building. Unlike inhibitors, polyurethane delayed catalysts have relative retardation rather than absolute retardation. They have lower front end activity and comparable overall activity compared to conventional catalysts, and they do not delay the reaction in systems without catalyst.

Depending on the application, we classify delayed catalysts into two categories: delayed catalysts for foams; delayed catalysts for CASE (CASE, polyurethane sealants, polyurethane sealants, polyurethane binders and polyurethane elastomers).

Delayed foam catalyst

Polyurethane foams include polyurethane rigid foams, flexible foams, semi-rigid foams and self-skinning products. The main reactions involved are the foaming reaction, the gel reaction and the trimerization reaction. Therefore, the catalysts commonly used in polyurethane foams are mainly classified into delayed foaming catalysts and delayed gelling catalysts.

The commonly used delayed-cracking catalyst is mainly DY-225, which is a diol solution of modified bis(dimethylaminoethyl)ether, which can delay the milking time and increase the accelerated aging of the early drooling.

The delayed gel catalyst mainly includes DY-8154 (modified triethylenediamine solution) and DY-300. In particular, DY-8154 is used more widely and is widely used in fields such as rigid foams, flexible foams, semi-rigid foams and self-skinning, and can be seen in certain microcellular elastomer formulations. To.

A new delayed catalyst different from the common catalysts on the market is a delayed catalyst specially developed for Desheng Chemical. Its main product is DY-215. It has the characteristics of low foaming efficiency, good retardation effect and strong gel effect, which can provide early fluidity and accelerate post-cure and demoulding. It can be used with most catalysts. In some formulations, it can be used as an alternative to organotin to increase early fluidity without affecting late maturity.

2. CASE delayed catalyst

Compared with the foam catalyst, the catalyst required for CASE has the characteristics of fast gelation speed, micro-foaming or even no foaming. Common catalysts include DY-12 (dibutyltin dilaurate) and DY-20 (organophosphonium). , phenylmercuric acetate and the like. Therefore, the delayed catalyst for CASE should have the same catalytic activity as tin and other catalysts. It is difficult to achieve the effect of mercury in foaming efficiency, so the effect of dibutyltin dilaurate should be as close as possible.

At the same time, the application of CASE is different from foam production. The materials and processes used are complex, the choice of polyether and polyester, the difference in isocyanate and the temperature and sequence of the synthesis steps bring about large differences in results. Therefore, the method of selecting a CASE product on a delayed catalyst cannot be generalized and needs to be determined based on a number of factors.