Sarah,
The answer comes from the chemistry of the "plastic" items. Although
celluloid was available for a long time, the expense may have been too great for
something as disposable as straws. I suspect that post war plastic development
by chemical companies created the plastic straw. Quite some time ago, I learned
that you can have a plastic object dissolved by a chemist who can then
recreated the formula for that item. With the formula, you can then research
patent dates for the item. Plastic changed almost overnight and each forumula has
its own patent.
Ron May
Legacy 106, Inc.