Glass-Reinforced Polyurethanes, a Well-Known Technology

1 Glass-Reinforced Polyurethanes, a Well-Known Technology 

In essence these systems carry out a job similar to that performed for very many years in the polyester chop-and-spray applications, the only differences being that polyurethane has a different profile of reactivity and viscosity build-up than polyester and that, at least in one case, the glass roving is conducted through the mixing device instead of being fed outside of it. 

A few practical problems have been identified in this technology, mainly deriving from the design of the mixing equipment currently available. In one case the chopped fibre is 

The main problem comes from the dry chopped glass that - leaving the nose of the head still not wet - flies everywhere near the mould surface. This results in negative effects on workers, on cleaning and maintenance operations, and on part quality. This problem can seriously hinder the application of this technology. 

Cannon started looking into this technology in the summer of 1997, at the urging of some car parts producers who were unsatisfied with the performances of the existing 

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