PU foaming catalyst role description

- Jun 25, 2018 -

1. Flexible block foam: A soft, bulk polyether polyol based foam is a typical tertiary amine catalyzed reaction product used with organotin catalysts. The gum catalyst can be a dilution of a pure compound such as triethylenediamine and bis(dimethylaminoethyl)ether, or a blend of properties optimized. Typical tin catalysts for foaming of soft blocks are pure or diluted stannous octoate. Dilution products (including amines and tin) are designed to solve the problems of raw material handling, metering accuracy, and pumping viscosity limitations. The use of high-quality blends for specialized foaming equipment can improve processing, broaden the range of formulations, and make small differences in the physical properties of the foam. The reaction properties of a soft bulk system require precise balance between foaming and gelling reactions. The premature foaming of the system before sufficient polymer viscosity/strength is obtained can result in coarse foam, cracks or blemishes. Premature gelation can result in low flow, high density, shrinkage of closed cells and foaming systems.

2. Soft Molded Foam: Soft mold foaming requires the same precise foaming/gelling balance as soft bulk foaming. In demolding, fluidity, stability and curing are further requirements. The triethylenediamine and bis(dimethylaminoethyl)ether and a small amount of dibutyltin dilaurate are the most commonly used catalyst systems in soft mold foaming systems. Frequently used phosphonic acid-protected limb-delaying catalysts allow the solidifying foam to have sufficient fluidity to pass through a complex-shaped mold.

3. Rigid foam: A wide range of uses for rigid foams (including appliances. Laminated and sprayed foams, in-situ castings, packaging foams, etc.) and chemical compositions (polyurethanes and polyisocyanurates). Polyurethane rigid foam from dimethyl cyclohexylamine. It is catalyzed by dimethylethanolamine, triethylenediamine, pentamethyldiethylenetriamine and pentamethyldipropylenetriamine. These catalysts can be used alone or in admixture. Polyisocyanurate rigid foams are generally prepared by using a mixture of trimerization catalysts, such as potassium octoate, potassium acetate or a tripolyamine catalyst containing tris(dimethylamidomethyl)phenol as a catalyst.