Derivation of the word oaktag

[Gerry Hurley]

Hi,

I'm a librarian and my husband asked me if I could find out
the derivation of the word "oaktag" (that kind of heavy paper
we all used in kindergarten).  It's also called tagboard and
sometimes posterboard.  I'm drawing a blank. I've searched
the web, looked at art web sites; used the paper and pulp
encyclopedia, dictionaries, encyclopedias, etc.  I can find
definitions and explanations of what oaktag it, but I can't find
any info on why/how the word came into being.

Another librarian suggested that this group might be
able to help me.  Thanks in advance for any assistance
you might be able to provide.

Gerry Hurley
email:  ghurley at ovid.com