ABSTRACT
Silicone surfactants are essential additives for the production of high resilience (HR-) polyurethane molded foam. The structural design of a silicone surfactant should match the different requirements of the various formulations in order to optimize the balance between both chemical stabilization and cell openness. This in turn helps to insure production safety and consistency.
This paper focuses on straight TDI 80 technology, being predominately used in North America. The TDI technology is used to provide high quality foams at lower densities. From the surfactant manufacturer’s point of view these foams, based on formulations including TDI in combination with polymer polyols, are so-called non-stable systems. Besides cell regulation, these systems require additional physical stabilization provided by the silicone surfactant. Simultaneously, the silicone surfactant must have a broad processing latitude leading to foams which are crushable with low force to open up the cells.
In addition, the automotive industry has increased its interest in low emanation (FOG/VOC) foams. Goldschmidt analyzed the composition of emanations from typical foam grades. Consequently silicone surfactants were optimized with respect to the lowest contribution to volatiles.
In this paper three new experimental products will be introduced, which were specially designed for North American type TDI formulations. They are the outcome of a large screening program making systematic variations of key structural parameters. The advantages of these products, concerning processing and bulk stability, will be demonstrated. Their impact on cell structure, skin appearance, and mechanical properties will be shown.
