Analysis of "PVC material" polyurethane delayed catalyst
发布时间： 2019-07-25 13:53 Author: Polyurethane foam machine Source: http: //motokone.com
Published: 2019-07-25 13:53
Polyurethane delay catalyst is an extremely special type of catalyst in polyurethane catalysts. This type of catalyst can provide the catalytic activity required for curing of polyurethane, and at the same time, it can extend the product life and provide more operating time for construction. Unlike inhibitors, polyurethane delayed catalysts are relatively delayed, not retarded. Compared with conventional catalysts, the front-stage activity is lower, and the overall activity is comparable. It cannot play the role of delayed response in a system without the addition of a catalyst.
According to different uses, we divide the delayed catalysts into two categories: delayed catalysts for foams, delayed catalysts for CASE
(CASE stands for Polyurethane Coating, Polyurethane Sealant, Polyurethane Adhesive and Polyurethane Elastomer)
Polyurethane foam includes polyurethane rigid foam, soft foam, semi-rigid foam, self-skinning and other products. The main reactions that have been touched include foaming, gelling, and trimering. Therefore, the commonly used catalysts for polyurethane foam are mainly divided into two types: delayed foam catalyst and delayed gel catalyst.
There are mainly delayed gel catalysts. The commonly used delayed foaming catalyst is mainly GST-225, which is a glycol solution of modified bis (dimethylaminoethyl) ether, which can delay the milky time, increase the flowability in the early stage, and accelerate the late maturation.
Delayed gel catalysts include GST-8154 (modified triethylene diamine solution), GST-300, and so on. In particular, GST-8154 is more commonly used. It is widely used in rigid foam, soft foam, semi-rigid foam, and self-skinning. It can also be seen in local microcellular elastomer formulations.
A new type of delayed catalyst. This type of product is different from the common catalysts on the market. It is a type of delayed catalyst specially developed by Gusite Chemicals. The main products are GST-215 and so on. It has the characteristics of low foaming efficiency, good delay effect and strong gel effect, that is, it can provide early mobility and accelerate post-maturation to accelerate demoulding. It can be used in combination with most catalysts, and can replace the use of organotin in local formulations to increase early activity without affecting later maturity.
Compared with foam catalysts, the catalysts required by CASE must have the characteristics of fast gelation speed, micro-foaming and even non-foaming. Common catalysts mainly include GST-12 ((organic bismuth), phenylmercury acetate, etc .. Therefore, the delay of CASE use The catalyst should be comparable to tin catalysts in terms of catalytic activity, and it is difficult to reach the mercury effect in foaming efficiency, and it should be as close as possible to the effect of dibutyltin dilaurate.
At the same time, the application scope of CASE is different from the consumption of foam. The raw materials and processes used are cumbersome. The choice of polyether polyester varieties, the different isocyanates, the temperature, and the sequence of the synthesis steps will all lead to huge differences in results. Therefore, the choice of CASE products on the delayed catalyst cannot be confused, and the demand is based on many factors.
The following figure is a comparison of the catalyst-free cured product and the cured product catalyzed by Gust Chemical Delayed Catalyst. It can be seen that the use of a suitable delayed catalyst can achieve the high efficiency and low foaming of tin-mercury products.
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