Alcohol gels

The following discussion took place in sci.chem

 Article: 3181 of sci.chem
 From: larry [at] kitty__UUCP (Larry Lippman)
 Newsgroups: sci.chem
 Subject: Re: Gelled Alcohol
 Summary: Some formulation details
 Keywords: alcohol gels
 Date: 24 Feb 91

 In article <26850002 [at] hpldsla__sid__hp__com>
     tonya [at] hpldsla__sid__hp__com (Tony Arnerich) writes:
 >> I have a friend who came from work at a nursing home this summer with a
 >> squeeze bottle of gelled isopropyl alcohol.
 >> It feels like "slime," (the toy stuff) and will remain gelled for a
 >> few seconds before evaporating in your hand.
 >
 >Pretty amazing. Is there any chance that there is another ingredient that
 >soaks into your hand? It doesn't necessarily have to evaporate to "disappear".

 In the case of lower m.w. alcohols such as ethanol and isopropanol,
 there is a 100% chance that another ingredient is present. :-)

 The technique of gelling alcohols with a suitable hydrocolloid as a
 gel-forming agent has been known for some time, but it has only been in
 the past several years that such products have become popular.  Since
 the percentage composition of the hydrocolloid and any other non-alcohol
 ingredients is well under 1%, and since such ingredients are
 comparatively inert and readily absorbed by the skin, there is no
 *noticeable* residue.

 It is more common for these alcohol gels to use ethanol instead of
 isopropanol, however, since ethanol produces a thicker and more stable
 gel.  Did the product mentioned in the original article specifically
 state on the container that it contained isopropanol?

 Two common hydrocolloids used in alcohol gel formulation are the
 Carbopol-series and the Polysorbate-series.  Carbopol, which is a
 tradename of B. F. Goodrich, is a water-soluble carboxyvinyl polymer,
 with a specific product example useful for alcohol gels being Carbopol
 940.  Polysorbate is a polyethyleneoxide fatty acid ester, with a
 specific product example useful for alcohol gels being Polysorbate 80.

 For any reader wishing to try their had at making an alcohol gel, a
 simple working formula is:

 Carbopol 9400.3 %
 triethanolamine0.4 % (needed for pH and stability control)
 ethanol       25.0 %
 water qs

 An example of an alcohol gel product is Purel [tm], which was introduced
 to the institutional market about four years ago by Go-Jo Industries.
 Purel is totally transparent, and is characterized by bubbles of
 entrained air.  The bubbles develop during the mixing process. I once
 asked "why not remove the air bubbles?", which would be easy enough to
 do, and was informed that customers prefer the appearance with the
 bubbles.  I would never have guessed that - which just goes to show why
 I don't do marketing and sales! :-)

 >> Its use is as a cleanser for when there is no water/soap to be had.

 These products are primarily aimed at the health care marketplace to
 reduce the possibility of cross-infection between patients.

 >> Local chemists have asked me if it leaves a residue, to which I
 >> responded, "No."
 >
 >Were you lying?

 That depends... :-)

 >> My question is: how is this done?  A surfactant?
 >
 >This seems unlikely, as that would leave yucky scummy slime.
 >Surfactants are rarely volatile (maybe that's the breakthrough
 >that makes this possible).

 The use of Polysorbate 80 fits the definition of a surfactant better
 than Carbopol 940.  A small enough quantity of a non-ionic surfactant,
 such as Polysorbate 80, is relatively inert and is readily absorbed by
 the skin. There is no issue of surfactant volatility, however.

 >Let's hear more about this. What is the brand name/product name? Do some
 >more experiments, like leaving some on a clean piece of glass and warming
 >it gently. Smell it - is it *just* like isopropyl alcohol, or is it subtly
 >different? Look closely at it in the gel state - is it cloudy or clear?

 I'd be interested in hearing about what other readers discover.

 As a closing comment, alcohol gels have been used for quite some years
 as a vehicle for other ingredients in some soap and cosmetic products.
 The most common example is "Edge" shaving gel, which contains ethanol.

 Larry Lippman
 Recognition Research Corp.
 VOICE: 716/688-1231
 FAX:   716/741-9635


 Article 3226 of sci.chem:
 From: larry [at] kitty__UUCP (Larry Lippman)
 Newsgroups: sci.chem
 Subject: Re: Gelled Alcohol
 Summary: Sources for chemical purchase
 Keywords: chemicals, purchase
 Date: 28 Feb 91
 References: <1991Feb27.232206.285 [at] ultra__com>
 Distribution: usa
 Organization: Recognition Research Corp., Clarence, NY
 Lines: 27

 In article <1991Feb27.232206.285 [at] ultra__com>
     bob [at] ultra__com (Bob Beach) writes:
 >Can anyone suggest where one might buy things like:
 >Carbopol 940
 >Triethanolamine
 >Polysorbate 80
 >in small quantities. I suppose I am looking for a good mail order
 >source or perhaps a store somewhere in the SF bay area. Any suggestions?

 The above chemicals are commonly used in product formulations rather
 than as analytical reagents.  Therefore, they can be purchased from
 wholesale chemical distributors rather than laboratory supply
 distributors.

 Check your Yellow Pages for a listing under "chemicals", and I bet that
 you can find a local source in any major city.  With some luck, you can
 probably buy in quantities as small as one gallon.  You may find that
 one gallon of a chemical in a commercial grade (as opposed to say, ACS,
 USP, NF, etc. grade) may cost far less than expected.

 If you are affiliated with a bona fide organization, you may be able to
 obtain small samples of the above type of products at no charge. Of
 course, your "purpose" in requesting such samples is "evaluation" before
 committing to a larger quantity purchase. :-)

 Larry Lippman
 Recognition Research Corp.
 VOICE: 716/688-1231
 FAX:   716/741-9635


 Article 3231 of sci.chem:
 Newsgroups: sci.chem
 From: whenry [at] lindy__stanford__edu (homo obsolescensis)
 Subject: Re: Gelled Alcohol
 Organization: Stanford University Libraries
 Date: 28 Feb 91

 In article <1991Feb27.232206.285 [at] ultra__com>
     bob [at] ultra__com (Bob Beach) writes:
 >Can anyone suggest where one might buy things like:
 >
 >Carbopol 940
 >Triethanolamine
 >Polysorbate 80
 >
 Carbopol 934 (I don't know about 940) and triethanolamine)
 are available from

 Conservation Materials Ltd
 340 Freeport Blvd.
 Sparks, NV  89431
 702-331-0582


 If anyone is particularly interested in the use of solvent gels in art
 conservation, I would be happy to provide photocopies of a very
 interesting article by Chris Stavroudis, a conservator of paintings in
 Los Angeles.  (This appeared in the newsletter of the Western
 Association for Art Conservation).  Send me a snailmail address.

 Walter Henry
 Assistant Conservator
 Stanford Univ Libraries

                                  ***
                  Conservation DistList Instance 4:46
                  Distributed: Saturday, March 2, 1991
                        Message Id: cdl-4-46-004
                                  ***