Thursday, October 29, 2009

UV Scale-Up

This past summer I spent a huge amount of time developing a UV-cured coating. Now that the lab work is done, we've started scaling it up.

You might initially think that the scale-up should be easy since there are none of the nasty surface/volume ratio scaling that normally occurs in reactors and all the implied heat/mass transfer/buildup issues that go with it. This is simple exposing a thin wet coating to a UV lamp for a short period of time.

But even in something as simple as this, there are a mess of potential problems. First off, the curing lamps are not even the same. Different manufacturers, different bulbs (and output spectra), different wattages and therefore different heat outputs. UV curing is more than just absorption of a UV photon. That is merely the initiation step. The remaining polymerization, crosslinking and termination steps are all subject to temperature conditions that (generally) do not plague the photoinitiation.

The coating methods are not the same either - in the lab I used a notched bar, but the pilot line has a type of roll coater. The low viscosity of the formulation that worked so well in the lab became problematic for the coater, so all the plans of looking at different coat weights ended up as something for the next round. We took what we could get.

Nonetheless, it appears that the formulation cured quite well, quite a bit faster than in the lab, although it does have a gamut of testing to run. Thank goodness we didn't have to look into other curing options: multiple exposures, different reflectors, bulb distance,...

Friday, October 23, 2009

Polymeric Auto Glass

Certainly this is a trend that is a long time coming, but the recent increase in the MPG targets are a de facto requirement for polycarbonate glazings. As much as PC will reduce car weight, it will also free up design. Look at the Qarmac concept car:
Those C-shaped windows just can't be done in glass. How much innovative design is being stifled because the glazings are still glass? Outside of the weight considerations, how much does that hurt aerodynamics?

Naturally, Bayer and SABIC, the two biggest manufacturers of PC are in the game, but in slightly different ways, although both are operating subsidiaries (BMS and Exatec respectively) which provide the materials. PC can't be used straight as it doesn't have the scratch resistance or weatherability (it will oxidize and turn yellow courtesy of the photo-Fries rearrangement) without a coating. BMS is going with a wet coat while Exatec is going with a plasma coating.

Sun/moon roofs are already being made so obviously the UV protection is solved to some degree. Given the repeated rubbings and abuse that windshields take, I would expect that application to be the last to go, but the sidelights should provide lots of fun in the meantime.

Tuesday, October 20, 2009

Patent Quality and Value

For reasons that I don't understand [*], assessing patents is a hot topic this week. Two new companies are out with assessment tools: Patent Site and Patent Board.

Assessing patent quality is much like assessing the quality of research articles - any logical approach is fraught with loopholes and errors. The most common basis for the analysis is to look at the citations of other patents, as these citations establish links to other relevant work. The more times a patent is cited, the better it must be (which implicitly assumes that all patent examiners cite all the relevant patents and no irrelevant ones). Certainly this is true for breakthrough patents, but for other patents that represent smaller increments of improvement, that would not be the case. And with patents, far more than with research reports, there is an economic aspect that outweighs all other aspects. Patents for blockbuster drugs are not cited nearly as much as their economic impact on the company would suggest.

An additional challenge that is becoming more important all the time is that patents can be assigned to others (exclusively or not). Patent Site claims to address this, but I don't see how that can be done given that most of these agreements are not public.

Lastly, I'm not surprised at all that these two companies come up with different results. Patent Site lists the top ten chemical companies as

2) Bayer
3) DuPont
4) Dow
5) Sumitomo
6) Mitsubishi
7) DSM
8) Solvay
9) Syngenta
10) AkzoNobel

while Patent Boards list is

1) DuPont
3) Dow
4) Honeywell
5) Nitto Denko
7) 3M
8) PPG
9) Chisso
10) Air Products

DuPont, Dow and BASF are near the top of both lists, but the other 7 candidates aren't even the same! Obviously, there field still needs additional work.

[*] I'd would guess that companies probably will use this as a PR tool to push the value of their portfolios, and since this analysis is so much more sophisticated than just counting up patents, it can used that much more so.

Monday, October 19, 2009


The number of rheology blogs is doubling everytime I look! At this rate we going to be outnumber the political blogs by Christmas.

The new guy on the web: The Rheol World.

Tuesday, October 13, 2009

Diodes, Diodes Everywhere

This is the week of the diode. Not the standard electrical diode that only lets current flow in one direction. Those exist everywhere - your computer is loaded with them and you can't recharge your cell phone without one. Instead, this is about rectifying other actions that are much more difficult to control.

Take heat for instance. In standard conduction patterns, it flows from hot to cold. But now if can be made to flow in one direction based on geometry, not temperature. By using two components, one with good conductivity at high temperatures but not low, and the other component with the opposite properties, the magic occurs.

A similar result (at a gross level) was found with a photonic crystal that directs microwaves in only one direction.

Since this is a rheology blog, proposing a flow rectifier would be appropriate. Check valves already exist (first in cardiac organs, then in human creations). A way to control reptation would be neat, and could certainly lead to some unusual rheology - it would take much longer for a given stress to relax. I'm sure the "much" longer could be quickly quantified, but I'm not the greatest at reptation theory and way to busy in the lab to hash through it today.

Tuesday, October 06, 2009

The Dog and Pony Show

You don't have to work (or be in grad school) for too long before you start getting asked to help with a dog-and-pony show. Being a service organization, we tend to more than most. That doesn't necessarily follow, does it? Let me try and clarify. Most of our work is short term (3 months or less) projects. Some of the projects will immediately lead to another, but most often not. Instead, there is a future project down the road. So we need to keep ourselves in their minds, and also look for new clients. The economic downturn has decreased the size of the projects and upped the time between.

Today's presentation was a doosey. Four of us gave 30 minutes background talks, followed by four 30 minute hands-on working sessions. Thank goodness I can just type this and not have to talk anymore. My voice is gone, my introversion character is rapidly rebelling and I need time to myself to decompress. Thank goodness the Twins game (#163 out of 162) is on in an hour. That and a beer or two.

I always have mixed emotions talking about rheology. I absolutely love the subject and can go on way too long, but the problem is that it is a very complicated and difficult subject. I keep thinking of that Einstein quote, about how if you can't explain it simply, you don't understand it. Some aspects of rheology can be explained simply, but a lot can't. And I don't think it's just me. I've yet to see an sub-undergraduate level explanation of time-temperature superposition.

Regardless, the day was certainly worthwhile - most people do not think of rheology, only gettin as far as viscosity. Looking behind the first curtain to see the storage and loss modulus is so informative (but for eternal enlightment, one must go the through the wall and seek the relaxation spectra!) Lots of good questions, which caused the schedule to lapse. Not a problem and that clearly showed we were getting somewhere. That doesn't pay the bills however, so we will soon see if we really hit the target.

Monday, October 05, 2009

Public to Private and Back Again

The motions of the business world never seem to stop, and so to the amusement. It's fun to watch a public company go private only to become public later. Kraton Polymers is the latest example. Originally part of Shell Chemical, they were spun off, bought out by a private group, and now are going public again with a $230 Million IPO.

The deal that still amuses me is KKR, the giant private equity firm. After spending it's entire corporate life inleverage buyouts and taking companies private, they announced an IPO themselves back in 2007, (although it never came go fruition).

Duplicity and Siloxanes

Finally got around to seeing the film "Duplicity". I liked it, but I've yet to see a film starring Clive Owen that I didn't like. Many reviews have said that the movie is confusing, but I think that is mainly due to the non-sequential order in which the story is told.

The film is about 2 former government spies (Clive Owen and Julia Roberts) who work for the corporate intelligence units of 2 competing companies. One of the companies has a huge new product coming out; the other is trying to find out what it is and then steal it. The spies are in cohoots with the idea of trying to cash in themselves.


I'm not going to tell you how it all ends, but I am going to talk just a bit about what the secret product is. Even knowing what the product is isn't really going to ruin the movie.

What impressed me most is that they actually got the chemistry right, but you don't initially realize that (the movie isn't called "Duplicity" for no good reason). The product is claimed to grow hair and cure baldness, and in what I initally thought was a mistake, the kind that Hollywood routinely makes, the formula is shown on a piece of paper to be a cyclic polysiloxane, although no professional chemist would bother to explicitly draw all the hydrogens and carbons.

I was laughing that they would try and pass off such a simple molecule as a drug, but that was actually the point. The whole "new product" never existed -it was just a bait to get the competitor to expose himself. In the end, the molecule is described as a lotion, although actually it might be a part of a lotion, but would never be a lotion itself - a small point.

A larger point that actually could have helped the competitor realize that the product was a fraud was that there were no clinical evaluations going on. Nobody can introduce a new drug without first registering it with the FDA and going through 3 phases of clinical evaluations - all of which are very public. Everyone knows what is in the pipeline of all the pharmaceuticals.