Adhesion: Silane and gum

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 Fri Mar 4 13:44:20 2005