Re: polivinyl alcohol vs. gelatin sizing

From: Katharine Thayer <kthayer@pacifier.com>
Subject: Re: polivinyl alcohol vs. gelatin sizing
Date: Sat, 30 Jul 2005 08:04:34 +0000

> I don't understand your answer to my question about why one would use
> PVA rather than acrylic medium. It's true that polyvinyl alcohol would
> require a hardener, but that would be a reason to use acrylic, not a
> reason to use PVA. And so on. So maybe my question wasn't clear; I
> still don't understand why PVA rather than acrylic.

Acrylic medium uses poly(vinyl alcohol-co-acetate) as the emulsifying
agent to hold polyacrylates like poly(alkyl methacrylate). This way,
in effect, much of the wet content being coated is actually a
copolymer of vinyl acetate and vinyl alcohol and water. I think these
polymers are better used in a small amount as an additive to gelatin.

In response to Giovann's post, I think gelatin is a lot easier to coat
as long as it is at the right temperature. Also, PVOH and acrylic
media are also susceptible to bacterial attack and products contain
biocides.
Received on Sat Jul 30 09:46:02 2005