New Additive Solutions for Low VOC in HR Molded Foams

Abstract

There is strong pressure on the suppliers of flexible molded foam for automotive seating to reduce the amount of volatile organic compounds (VOC) in their products.

At the moment the main sources of VOC are the catalysts and silicone surfactants. The most effective means to reduce or even eliminate the VOC originating from the amine catalysts would be the use of amines containing reactive groups such as primary or secondary amine and/or hydroxyl groups. These loose however a lot of their activity when they are built into the foam structure, which hence might lead to insufficient flow and / or curing. A careful balance of chemical reactivities and catalytic activities is therefore needed.

Nitroil(r) Performance Chemicals carried out a study on the performance of a number of such reactive amine catalysts, in combination with other reactive or non-reactive amines. The main focus was of course on VOC, but maintenance of acceptable processing and physical foam properties was another major requirement. A series of combinations were evaluated in a TDI-based standard formulation and compared to a combination of traditionally used non-reactive amine catalysts.

In this presentation, it will be shown that the use of reactive amines led to a considerable reduction of VOC. By using only reactive amines, a VOC reduction of ca. 50% was obtained, and virtually no amine was present in the VOC. Good foam processing was obtained while physical foam properties were not significantly affected, with the exception of HACS. This property suffered from the use of reactive amines. By using PC CATS HPI as the basic catalyst in combination with a non-reactive amine as "blow" catalyst, the values for all physical foam properties, including humid aging compression set (HACS), were quite acceptable, while a VOC reduction of ca. 20% was obtained.