Re: Adhesion: Silane and gum

Sorry to learn that your silane didn't work with gum.
Looks like the aminopropyltriethoxysilane has not sufficient "affection"
vis-a-vis gum (the good news being there are several hundreds of silanes to
try).

> > The wet gum coating didn't stick as well to the silane-treated glass
> > as it does to plain glass (...).

Did you use acetone on both glass sides? I ask because acetone (unless of
optical/spectroscopic grade) might leave impurities on glass.

> > The exposed and hardened gum frilled off the silane-treated glass
> > exactly as it would from plain untreated glass.

Would it help adding a few drops of surfactant to the coating solution?

Martin

----- Original Message -----
From: "Katharine Thayer" <kthayer@pacifier.com>
To: <alt-photo-process-l@sask.usask.ca>
Sent: Friday, March 04, 2005 3:17 PM
Subject: Re: Adhesion: Silane and gum

> P.S. Whoever said that silane might be difficult to remove from glass
> wasn't just woofin'. I've spent an hour and five razor blades scraping
> away at it and there are still places where it just won't come off. If
> this were just regular window glass, I'd toss it, but this is non-glare
> glass that I paid $8.75 a sheet for, so I've got to keep at it. (If
> anyone's interested, the etched side of the glass is the side the print
> is viewed from; the gum is printed on the back (non-etched) side of the
> glass).
> Katharine
>
>
> Katharine Thayer wrote:
> >
> > I've obtained some silane which I hope is the same silane mentioned
> > below (Martin Mueller's post from Feb 5). The supplier calls it gamma
> > aminopropyltriethoxysilane and it's what they sent me when I asked for
> > 3-aminopropyltriethoxysilane. I've seen the two names used
> > interchangeably and they have the same CAS number, so I'm hoping it's
> > the same substance. (Sorry, my knowledge of organic nomenclature is far
> > in the past so I can't tell by looking at the names why they would be
> > the same thing).
> >
> > At any rate I've applied this silane, mixed 1% with acetone, to two
> > carefully cleaned and de-greased and alcohol-treated (thanks Galina!)
> > sheets of glass, left them overnight, and printed gum on them this
> > morning. Some observations:
> >
> > (1) The wet gum coating didn't stick as well to the silane-treated glass
> > as it does to plain glass, nor did it brush as smoothly as it would on
> > plain glass; it seemed to be phobic to the silane.
> >
> > (2) The exposed and hardened gum frilled off the silane-treated glass
> > exactly as it would from plain untreated glass.
> >
> > (3) An added annoyance: Dichromate stains along the edges of the
> > brushmarks, that simply will not clear with potassium metabisulfite
> > treatment.
> >
> > However, now that I have re-read Martin's post one more time, I think I
> > need to try it again, because I didn't apply it exactly as he
> > recommends. I misremembered the directions and applied the material
> > with a tissue and then simply left it to evaporate, instead of rubbing
> > it til it evaporated, as instructed.
> >
> > So I will try it again, following the instructions precisely, but this
> > can't happen until there is another nice day, (it's raining today)
> > because I have to work outside with the acetone.
> >
> > Katharine Thayer
> >
> > MARTINM wrote:
> > >
> > > Another approach consists of using silane for the subbing: rub the
> > > (clean/degreased!) glass plate with a 1% freshly prepared acetone
solution
> > > of 3-aminopropyltriethoxysilane over one or both sides with a tissue
for
> > > about 1 min until the solvent has evaporated. Allow the glass plate to
stand
> > > for several hours to ensure reaction of the silane. On that layer your
gum
> > > solution will firmly adhere.
> > >
> > > Some time ago (maybe in 2002 or 2003 - take a look at the archives)
Philippe
> > > Monnoyer recommended incorporating silane into a gelatin solution. It
may be
> > > a good idea to add a small amount of that above mentioned silane
mixture to
> > > your gum solution.
> > >
> > > Martin
Received on Sat Mar 5 02:47:30 2005