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/LE1LGUMPVA 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-PVAfully 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.htmA 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=152Some more information:
http://www.fao.org/fileadmin/templates/agns/pdf/jecfa/cta/61/PVA.pdfIt 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.pdfAlso Gutterman Sulky Solvy:
http://www.sulky.com/stabilizers/solvy.phpVarious 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/VinylonNorth 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/