There is a bit of a debate over the proper term for this. Depending on which reference you hit up, you might find it called
synecdoche or
antonomasia (or for the
extra-precise,
inductive antonomasia). I prefer the latter. A
synecdoche is a reference which utilizes a part of an assemblage to refer to the entire collection, for example calling a computer, a monitor, a keyboard and mouse 'the computer.' It uses one part which is
different from the other parts as shorthand. However,
antonomasia is the use of a single proper name to refer to a class; for example, calling someone a 'Solomon' instead of a 'wise man' - which is more appropriate here, as one substitutes a proper (brand) name for a class (of product).
This is why Frisbees are always labelled "Frisbee Flying Disc." Some other examples:
Clarification: It's Sellotape in the U.K. and Scotch tape in the U.S. I mentioned it because sellotape had been mentioned earlier.