Application of mold release agent in production of polyurethane foam

Polyurethane foam has good adhesion with many materials. Therefore, release agent should be coated on the surface of the mold during molding to form a thin isolation layer between the whole foam skin and the middle of the mold to facilitate the demoulding of products. There are two types of release agents: internal release agent and external release agent. The former is added to the material. However, the most commonly used is external release agent, which can be mainly divided into two categories: organosilicon and paraffin.

In addition to requiring the release agent to have good demolding performance, for external release agents, it is necessary to consider whether the selection of the demolding system has an impact on the surface quality of the product. For example, solutions or aqueous dispersions of paraffin wax with a melting point of 90 ℃ or 110 ℃ in organic solvents, polyethylene wax hydrocarbon solutions, organic silicon solutions, etc.
 
        In order to improve production efficiency, internal release agents have been developed as important additives for RIM polyurethane (urea). Internal release agent is an auxiliary agent added to the formula to play a demolding role. The types of internal release agents include polydimethylsiloxane compounds containing active organic groups, fatty acid polyesters, adducts of higher fatty alcohols or amines with ethylene oxide, zinc stearate, etc.