Is polythene the same as polyethylene?

Not knowing the answer to your question, I decided to do some research. A
great number of glues say they will not work on polyethylene. I only found
one that said it would; a 3M spray adhesive. But your application doesn't
sound right for a spray adhesive.

Some people say they have had success with hot melt glue. I tried it once
and it didn't work; but YMMV.