Re: Adhesion: Silane and gum

MARTINM wrote:
>

> Looks like the aminopropyltriethoxysilane has not sufficient "affection"
> vis-a-vis gum (the good news being there are several hundreds of silanes to
> try).

Yippy-skip! :-) Actually, I can't think of any reason why I would
pursue this line of inquiry any further. I was willing to try it once,
since people I respect seemed so sure it would work, but I sure am not
willing to try hundreds, or even dozens, of different ones on the odd
chance of finding one that would bond chemically to crosslinked gum. (If
nothing else would stop me, the expense alone would prohibit this
fishing expedition, but I'm also not interested in spending any more of
my time or energy on it).

>
> > > 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.

No, I didn't use acetone on both sides of the glass, but I'm not sure I
understand the question. I'm using non-glare glass which is etched on
one side; the etched side is the viewing side. So there's only one side
to put the acetone on. Am I missing something? Would IPA be a better
solvent? Weren't you the one who recommended acetone? At any rate, it
seems like this would only be an issue for the bonding of the silane to
the glass, and that wasn't a problem, it stuck like cement.

> > > 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?

I don't see why it would.

Katharine

 
>
> ----- 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 09:18:44 2005