At my previous position at an a contract R & D company, I always love to hear a client say "Oh, we tried that and it didn't work". What it usually means is that they tried some small subset of "that" and it didn't work, such as, "we tried polyethylene and it didn't work". Which polyethylene? High density? Low density? Linear low density? Ultrahigh molecular weight? Crosslinked? Ethylene copolymers? Filled? As you can see, there are plenty of possibilities even for something as restricted as polyethylene, and it is pretty unlikely that someone tried them all.
More amazingly, I have heard clients say that they tried polyurethane and it didn't work. Oh sure you "tried polyurethane". You tried every polyurethane out there including all the various combinations that could be made in any chemistry lab equipped with a balance and a mixer? To be fair, these clients were experts in areas other than polymers so it's not as if they were all around blockheads, but just outside their area of expertise. (Which was all for the good because if they were polymer experts, they wouldn't have approached us.)
But somehow I expect someone with over $100,000 to spend and some obvious background in polyurethanes to do better. That is not the case in this Ninesigma Request for Proposal, Alternatives to Urethane Hot-Melt Adhesives. The logic behind seeking alternatives is exactly the same as "Oh we tried that and it didn't work". Specifically,
"Polyurethane hot-melt adhesives have become a standard for applications bonding wood to other substrates, including wood, metal and composite materials. Many of the desirable properties of such adhesives lie not in the base polyurethane but derive from an increasingly complex array of additives that tailor performance to the exact bonding needs. Large numbers of custom providers, each touting their unique advantages, supply such adhesives. Finding reduced cost adhesives that meet growing performance expectations is a complex and never-ending pursuit."The RFP has a list of technical requirements, but also clearly states that no polyurethanes need apply. As if they have looked at all the possibilities out there. Wow. To exclude such an expansive and versatile set of chemistries, for no other reason than "we tried it and it didn't work" is mind-boggling. There are plenty of legitimate reasons for excluding polyurethanes, such as the isocyanates or cost or their lack-of-greeness, etc., but "we tried it and it didn't work" is not one of them.
Solving technical problems is hard enough; arbitrarily excluding a set of solutions only makes it that much harder.
[*] Not really. It's not that I disagreed with their vast range of properties and their versatility; I just didn't think that other polymers that are just as versatile got the credit they deserved.