PVC needs a plasticizer to be flexible (afaik) Gasolene tends to leach
out the plasticiser causing embrittlement. (My guess) PU does not, the
polymer can be modified to many elasticity values. Also there are
polyether Urethanes and polyester ones. The latter are better quality
and less susceptible to hydrolysis.
Graham
Duncan & Ami McFadyean wrote:
> <ami@mcfadyean.freeserve.co.uk>
>
> Does anyone know how to tell the difference, based on melting point. The
> urethane stuff has a higher melting point than the PVC. So, for example
> one will melt on a medium iron whereas the other won't??
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