Interesting... I worked HAZMAT for a few years many years ago and we had
PVA gloves that seemed almost impervious to everything but water. You could
wash them right off your hands in plain water but that protected you like
nothing else in many strong substances
.
On Tue, Jul 10, 2012 at 7:09 AM, Robin Whittle <rw@...> wrote:
> ∗∗
>
>
> Still more information on Poly Vinyl Alcohol, including the availability
> of water-soluble film for embroidery.
>
> (In the Yahoo Group archives, to view the diagrams and properly indented
> links, please use "Show Message Option > Use Fixed Width Font.)
>
> The proper name for Poly Vinyl Alcohol is "PVA", though "PVOH" is
> sometimes used. The proper name for Poly Vinyl Acetate is "PVAc", but
> most non-technical people refer to it as "PVA". In the following, "PVA"
> refers to Poly Vinyl Alcohol.
>
> I air-dried 10 grams of the Craft Smart Paper Gum glue (gently, over a
> day, in warm air, on a layer of wax) and the result was 1.4 grams of
> clear, tough, somewhat stretchy plastic film.
>
> From the MSDSs, it seems the exact same glue can be bought for $16 a
> litre as "Gloo Clear Gum":
>
>
> http://www.officeworks.com.au/retail/products/Office-Supplies/Stationery/Adhesives/Glues/Craft-Glues/LE1LGUM
>
> PVA is apparently unique among polymers in that it is not created
> directly by polymerizing monomer molecules, but by stripping off parts
> of an already existing polymer. This process may be referred to as
> "hydrolyzation", but "saponification" and "alcoholysis" may also be used.
>
> Fully hydrolyzed PVA has the following structure, where the carbon
> backbone is really zig-zag, rather than straight as shown here:
>
> H H H H
> \ / \ /
> <-C---C---C---C->
> / \ / \
> H O H O
> \ \
> H H
>
> Partially hydrolyzed PVA has some of the O-H groups remain in their
> initial state of:
>
> ∗ H
> \ /
> O==C--C-H
> \
> H
>
> where the ∗ is the second carbon on the first diagram.
>
> So fully hydrolyzed PVA is like polyethylene but with every fourth
> hydrogen replaced by an OH hydroxyl group. These hydroxyl groups are
> water soluble, while the plain H hydrogens are water repellent.
>
> According to:
>
> http://www.britannica.com/EBchecked/topic/469236/polyvinyl-alcohol-PVA
>
> fully hydrolyzed PVA is highly soluble in water and partially hydrolyzed
> PVA is partially soluble in water.
>
> We are interested in the partially hydrolyzed stuff, which is also used
> as a moisture-containing coating on food items and tablets, and in
> water-soluble packaging. See my next message for why I think "dissolvo"
> paper is not made with PVA.
>
> Companies which make water-soluble PVA film:
>
> http://www.pva-film.com/en/product_Features.html
> http://www.kuraray-am.com/pvoh-pvb/poval.php
> http://www.solublon.com/about_aicello.htm
>
> A Melbourne source of PVA water-soluble film (and Methyl Hydroxyl Propyl
> Cellulose "dissolvo" paper) is:
>
> http://www.daieiaust.com.au/plastic.php?la=la&cid=152
>
> Some more information:
>
> http://www.fao.org/fileadmin/templates/agns/pdf/jecfa/cta/61/PVA.pdf
>
> It seems that water is the only proper solvent for PVA. I was hoping
> there was a hydrocarbon solvent so it could be sprayed in solution onto
> paper, without the paper becoming soggy, as it does with water.
>
> However, there's another approach - either printing onto the PVA film
> itself, or bonding in some way (heat and pressure lamination?) the film
> onto some paper.
>
> Most water soluble PVA films seem to be used for industrial and
> packaging purposes. An exception is their use for "embroidery
> stabilizers". There can be a problem embroidering soft, thick, fabrics
> - and the solution is to lay a transparent PVA film over the top of the
> fabric (maybe bonding the two together?) before starting the embroidery.
> The film stops the stitches going too deep into the fabric. Then the
> film can be largely torn away, with the remainder being dissolved in the
> first wash.
>
> Products include Gunold Solvy. The MSDS indicates it is 100% polyvinyl
> alcohol:
>
> http://www.gunold.de/Home/Products/Foils/SOLVY/270
> http://www.gunold.de/images/productdwn/Sh_Solvy_GB.pdf
>
> Also Gutterman Sulky Solvy:
>
> http://www.sulky.com/stabilizers/solvy.php
>
> Various Solvy products can be purchased via eBay.
>
> I haven't researched these further, but there are multiple such products
> available at a nearby Spotlight craft and fabric shop, which is where I
> got the glue:
>
>
> http://www.spotlight.com.au/inspiration/projects/get-the-basics-g%C3%BCtermann-sulky-stabilisers/
>
> including "Totally Stable" which "can also be ironed onto light coloured
> fabric so that it can be put through an ink jet printer."
>
> I will check these out in the next few days.
>
> As a curious aside, PVA can be used to make fabric:
>
> http://en.wikipedia.org/wiki/Vinylon
>
> North Korea has the only substantial factory for this. It is pretty
> poor fabric in most respects, "stiff, uncomfortable, shiny, prone to
> shrinking, and difficult to dye" but they make it because they can use
> just coal (anthracite) and limestone, without any reliance on oil.
>
> - Robin http://www.firstpr.com.au/pcb-diy/
>
>
>
--
If you ask me if it can be done. The answer is YES, it can always be done.
The correct questions however are... What will it cost, and how long will
it take?
[Non-text portions of this message have been removed]