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Both Roland and Kawai (and others?) have claimed that their ivory-feel key surfaces "absorb moisture" or "absorb perspiration".

Aside from how repellent that sounds (I mean, who really wants to play a keyboard saturated with sweat?), the scientist in me is a little sceptical. A drop of water spread over the surface of the keys separates into little bubbles like it would on any other piece of plastic. Eventually they evaporate, but I can't see any evidence of absorption.

Can anyone supply any more information about the origin of these claims, the nature of the supposedly absorbent plastic, or quantitative data showing rates and limits of absorption, etc?

Sure -
Check out the Kawai patent here:
http://www.google.com/patents/US5223652

They claim the material they developed for key tops here has a BET specific surface area of 260 m^2 /g and above. You can search about BET specific surface, but it is an effective surface area for the capability to adsorb gas molecules per gram of material (especially micro or nano particles in a matrix) measured according to a standard procedure. For comparison, vitrified rock on the other end of the scale is 0.0016 m^2/g.

Best wishes-

Sounds like a daily spray of anti bacterial is called for here. . .l used to be bothered by sweaty, or more often' over dry fingers slipping off the keys of my non sweat absorbing plastic surface. But at my age now, it doesn't seem to trouble me any more. Don't know why, maybe others have experienced this too. . .

- I noticed that a while back but flat-out disbelieved it - such a horrible prospect; a unique organic compound formed of a bonding with my sweat.

Thanks to phacke I see it's either a typo (it should read 'adsorb' - something like 'sticking to', instead of 'absorb' - assimilating) or they've got a bunch of very mad scientists working at Kawai.

I don't know a thing bout how does it physically works but indeed my HP-305 used to have a very good keyboard surface, very comfortable, very "safe" grip to the figers and it is true that it seemed to be no trace of moisture/sweat after playing.

Why am I speaking in past sense? Because this original Ivory Feel surface, despite its marvelous qualities soon became "ivory peel". It started to disintegrate (literally, there are a few old threads about this issue...). So I called Roland for warranty and they replaced the old Ivory peeled keyboard for a brand new one. It's not peeling anymore but the new ones are more like those old fashion plastic keys only with a slight darker color and a few stripes imitating I don't know what (but it's kind of beautiful in some way...). They are no longer those wonderful feeling adherent keys, and definitely don't absorb moisture anymore. I guess you cannot have everything at once...

Of course, the word "absorb" was probably used to describe it in terms laypeople would understand. But I agree, if you think about it that sounds pretty icky. I don't normally have sweaty fingers, but I do enjoy the Ivory Touch surface. Here's their description from the website:



Obviously intended as a sales pitch and describing as best as possible without getting overly technical.

The thing is, if you have a key material that is porous and directs moisture and oil away from your skin, it actually is icky! There's no getting around it. Ivory keytops have always been known to discolour over time due to absorbing that icky stuff - these new keytop materials have similar properties, AFAIK. The only question is how icky is too icky for a given person. Personally, I don't like the idea of the icky stuff. I don't mind plastic keytops. They feel fine on my DP and my Yamaha acoustic. If I did have an ivory feel keyboard, I'd try not to think about what's going on under my fingertips!

That's why I wash my hands before I play.
I like icky!

My Petrof has ivory keys that aren't yellow at all. I think the yellowing has to do with not getting any natural (indirect) light, because mine have been the same for a long time, but they started out a bit yellowy when they sat in the piano storage room for years. I did purchase a few years back some ivory cleaner (Key Brite) and perhaps that would be good to use on these other keys as well. I have not noticed any discoloration on my MP11 keys either.

Thanks! That patent covers the black keys, but there's another linked covering the whites.

It seems the patents (from 1990 and 1989) describe making keys out of cellulose acetate (the stuff used for eyeglass frames) mixed with silica gel, a plasticizer, and dye.

The cellulose acetate and silica are chosen for their hygroscopicity (ability to absorb / adsorb water). The silica also increases the hardness of the plastic.

According to Wikipedia:

Assuming we're not going to be sticking our piano keys in the oven regularly, this raises the question of how long the keyboard will last before becoming fully hydrated. I can't imagine the volume of water that can be adsorbed by the tiny granules of silica present at the surface can be very high. What happens if you wipe the keys clean with a damp cloth... do they soon loose their adsorbent properties?

I would guess the system used in the keys is not as straight-forward as the single component silica gel situation.

I think the issue going on is not that of absorbing liquid sweat, but avoidance of condensation of vapor phase transpiration from the warm, humid fingers to the colder keys.