Polypropylene

Cathy Atwood provided some interesting and useful information about
polypropylene, so hopefully she, or someone else will be able to answer
a question I have wondered about for many years. Sometime before 1985, a
representative from Mobile Oil came to visit us. He had a sample of
"homopolymer polypropylene" with him, and told me they had spent one
year and $100,000 trying to seal this material. I sealed it for him on
one of our Polyweld polyester sealing machines, and he was really
excited. The Polyweld machine seals materials that conventional sealing
machines will not seal, but conversely, the Polyweld machine will not
seal the usual plastics we see in commercial products. Some years later
I learned that  polypropylene products were being made on "typical"
plastic sealing machines. I've always wondered what the difference is
between the pure polypropylene Mobile Oil gave me, and the polypropylene
sealed on normal plastic sealing machines. Does anyone know?

Bill Hollinger
Conservation Resources

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                  Conservation DistList Instance 8:78
                 Distributed: Thursday, March 23, 1995
                        Message Id: cdl-8-78-009
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