Re: Adhesion

From: MARTINM <martinm@SoftHome.net>
Subject: Re: Adhesion
Date: Sun, 13 Feb 2005 12:25:32 +0100

> I am not sure whether the 3-aminopropyltriethoxysilane is the best
> silane to use when dealing with gum arabic
> solutions. 3-aminopropyltriethoxysilane used to be the standard
> agent to promote gelatin (silver-halide emulsions) adhesion on
> glass.

Did you find the patent numbers you mentioned? I've never seen a
silane agent used for improved adhesion in the photosensitive layer.
Silane compounds are often used as a reduction sensitizing agent
and/or a crosslinking agent in silver gelatin patents.

Do you actually make silver gelatin emulsion, mix
3-aminopropyltriethoxysilane and coat glass with it? Do you see any
adverse effect like increased fog (especially with gold
sensitization)? If there's no increased fog, what kind of emulsion are
you using?

Cases I've seen of using 3-aminopropyltriethoxysilane and other amino-
epoxy- and other silane compounds as an agent to improve adhesion use
a separate subbing layer of material more hydrophillic than the base
substrate but less hyrdophilic than gelatin, such as butadiene
copolymers, methacrylate copolymers, vinylidene chlorides,
polyurethane, etc. These are described in US Patent numbers 6,300,048
and 6,348,305, and references therein.

These polymers, butadiene and vinylidene chloride in particular, are
used as a subbing material on corona discharge treated polyester film
bases to improve adhesion. Fuji even sells their stylene butadiene
latex copolymer in a bottle.

--
Ryuji Suzuki
"Well, believing is all right, just don't let the wrong people know
what it's all about." (Bob Dylan, Need a Woman, 1982)