posted on 2008-07-31, 10:05authored byA.M. Abdul-Rani, Neil Hopkinson, Phill M. Dickens
Flexible polyurethane foam is often molded directly into preheated tools for foaming reaction which
expands to fill the mold cavity. The foam that is directly in contact with the mold surface cures as the foam
skin. Parts frequently have surface defects ranging from shrink marks, to voids, to mottling and knit lines.
There are many possible causes such as applying too much or too little release agent, or mold surface not
cleaned and conditioned as required before the foaming process. Uneven mold temperatures are also
suspected to be a cause of surface defects, especially in high-resilience (HR) cold cure polyurethane foam
systems. A specially designed mold capable of maintaining tight temperature tolerance was built to produce
foam samples at varying temperatures. The effects of mold surface temperature on the foam surface texture
are studied and analyzed. The effect of processing temperature on the macro and micro surface texture is
examined. It is shown that the processing temperature has a significant effect on the foam surface texture.
3D topographical analysis of foam surface texture discovered a trend from samples produced at varying
temperature from 30 to 80 C.
Funding
This research is funded by EPSRC and assisted by Collins and Aikman UK
and Rojac Tooling Technologies Ltd.
History
School
Mechanical, Electrical and Manufacturing Engineering
Citation
ABDUL-RANI, A.M., HOPKINSON, N. and DICKENS, P.M., 2005. Effect of mould temperature on high-resilience cold-cure flexible polyurethane foam surface texture. Journal of cellular plastics, 41 (2), pp. 133-151.