[pure-silver] Re: Kodak Anti-foam B
- From: "Ryuji Suzuki" <rs@xxxxxxxxxxxxxxx>
- To: pure-silver@xxxxxxxxxxxxx
- Date: Tue, 10 Jan 2006 18:57:28 -0500
Jerry, can you stop referring to my posts from other places out of
context?
Tergitol L-62 is a surfactant that has wetting and defoaming properties
but the defoaming property is too lousy.
Coating aids (surfactants) used in emulsions coated by high speed
coating machines used these days are very powerful foamers. Those
coaters have to have very rapid reduction of dynamic surface tension as
the film surface is applied with the emulsion. This is achieved by a few
classes of surfactants but anionic surfactants with sulfonate as the
hydrophillic end are used most commonly, probably in blends. Those
surfactants make very rich foam when released in processing solution in
rotary or inversion tanks. These foams cannot be broken by another
surfactant, including TL62. You'll need a lot more powerful defoaming
agent.
A lot of surfactant research is done in industry, and most of them are
highly optimized for specific applications. Details of surfactant
compositions, blends and additives are largely proprietary. I happened
to have to research some of them deeply because of my emulsion projects,
but most people are better off buying what's known to work. It just
takes a lot of work to find one that works well, and if you buy
candidate surfactants and test them, you'll left with lots of
surfactants that are no good for your applications. It's not worth your
time.
Incidentally, in my practice, Tergitol L-62 was soon found to be
inferior for anything but very slow hand coating and I replaced it with
a blend of 2 surfactants and nonsurfactant additives (neither one of
these surfactants is similar to TL62). This works a lot nicer even at
moderately fast coating speed I've been using, while avoiding foaming
problem. HOWEVER, even my surfactant mix is unusable at the speed at
which films are coated in Kodak and Fuji plants. Fuji's latest coater is
apparently using a LOT of anionic surfactants.
On Tue, 10 Jan 2006 15:33:51 -0500, "Koch, Gerald" <gkoch02@xxxxxxxxxx>
said:
> Antifoam B is a mixture of 3 things including dimethyl siloxanes. What
> you mention may be the dimethyl siloxane. Unfortunately, the MSDS does
> not give a CAS number. It therefore is not the same but might work.
> There is also Tergitol L-62 which is a surfactant with both wetting and
> defoaming capability. It is completely water soluble.
>
> -----Original Message-----
> From: pure-silver-bounce@xxxxxxxxxxxxx
> [mailto:pure-silver-bounce@xxxxxxxxxxxxx] On Behalf Of Jim Brick
> Sent: Tuesday, January 10, 2006 3:18 PM
> To: pure-silver@xxxxxxxxxxxxx
> Subject: [pure-silver] Re: Kodak Anti-foam B
>
>
> Do you think that this:
>
> http://tinyurl.com/ajj5u
>
> is the same stuff?
>
> Many thanks,
>
> jim
>
>
> At 11:32 AM 1/10/2006, Koch, Gerald wrote:
> >Kodak and others sold the Hill product under their name.
>
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