Polymers, both Trademarked and Generic

Somewhat surprisingly, polymer trademarks have often gone generic. Maybe not "generic" in the legal sense where anyone is free to use the word, but certainly generic enough that the public is unclear about what is and isn't trademarked. Consider the following examples:

• Styrofoam. This is probably the best example of a polymeric product that has lost most of its original meaning. Dow owns this trademark for their expanded polystyrene boards used as insulation (and some crafts applications). And that's it. It has nothing to do with coffee cups, takeout food containers, packaging peanuts, beer coolers, ceiling tiles or anything else. This is an case where the public is taking the original product name and expanding it [GRIN] to other products.
• Mylar. Mylar is Dupont's tradename for PET film. This is a strange example as it is one of the few cases where the public has a more limited understanding of is trademarked. It is generally believed that it only applies to aluminum-coated PET films, such as are used to make helium ballons and not all PET films, even clear ones.
• Saran (not to be confused with Sarin, the nerve gas). This is one that leaves me confused as you will see. In fact, the public really hasn't genericized the term at all - the trademark owner has. Let me explain. Saran was originally a Dow trademark for PVDC - polyvinylidene chloride. When I worked in the food packaging arena, engineers would speak of Saran as the equivalent of PVDC, regardless of who made it. Some years ago, Dow sold the product line to S.C. Johnson who still makes it. No, wait, they don't make it. Well, they make Saran, but it isn't Saran. Or at least it isn't PVDC. S.C.Johnson, concerned about chlorine in their products ending up in the environment, now sells only polyethylene film under the Saran trademark. This is the only case that I am aware of where the trademark now protects an entirely different product that what it originally did.
• Nylon. Another Dupont trademark, and seeing this one going generic has twice the sting for them. Nylon is Dupont's trademark for aliphatic polyamides. Dupont makes them by copolymerizing diamines with diacids. For a product like Nylon 6,10, the 6 indicates the number of carbons in the diamine and the 10 indicates the number of carbons in the diacid. Dupont patented this process and thought they had it nailed up tight, only to find out that BASF could get around it. BASF developed a process for the ring-opening polymerization of lactams - a molecule where the acid and the amine are in the same monomer. Seeing a competitor work around a patent always hurts, but this must have really caused some coronaries in Wilmington: BASF used the same name and numbering scheme for their new product. A lactam ring with 6 carbons polymerizes to form Nylon 6. Ouch. Double ouch.