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Re: [BKARTS] PVA
PVA is an extraordinarily versatile adhesive used
in a multitude of applications in a host of industries -
bookbinding, printing, packaging, woodworking,
electronics, and other types of manufacturing, as
well as being packaged for retail customer use
As reported below, its development arose out of
adhesive shortages during WW II.
Also noted is that formulations of PVA-based
adhesives include different types application-specific
additives suited to the specific needs of those
Bookbinding is one such application, having particular
requirements and requiring special types of additives
For hand bookbinding, we want an adhesive that :
flows smoothly and can be applied in thin layers, can
be thinned with water to adjust tack time, will bond
pyroxlin-coated bookcloths (used to repel water, dirt,
etc.), will dry within a reasonable time, is strong, won't
age, is not affected by environmental factors (e.g.,
won't absorb atmospheric humidity or pollutants), is
flexible and transparent when dry, etc. We'd also like
it to be reversible, but...
Contrast these properties with woodworking formulations
that are stronger than the wood they bond, include dyes to
match wood colors, dry hard so they can be worked
like wood, etc.
Also contrast hand binding requirements with those
specific to machine binding (see Tony Clark's
"Bookbinding with Adhesives," McGraw-Hill (1988).
Consequently, while there are many PVA-adhesives
available, we use those that are specially formulated
for bookbinding (e.g., check Talas's catalog online).
In a pinch, something like Elmer's can be a satisfactory
substitute, but woodworking adhesives usually can't.
The same can be said for methyl-cellulose based
adhesives (an important ingredient in Gummy Bears,
laxatives, and pharmaceuticals).
Kantrowitz, Morris S.
Miscellaneous Bookbinding Adhesives
GPO-PIA Joint Research Bulletin,
Bindery Series No. 4 (1953)
Government Printing Office - Printing Industries Association
Because of wartime restrictions placed on the quantities of animal glue
available for use in the production of adhesives in the Government Printing
Office, a study was made of various synthetic resins early in 1943 for the
purpose of ascertaining whether or not some of these might prove satisfactory as
substitutes for the glue compositions employed by the bindery.
This investigation led to the development of several resinous adhesive formulas
employing as the principal constituent a water emulsion of polyvinyl acetate
resin. This compound, manufactured commercially as a heavy milky white emulsion
similar in consistency to liquid glue, exhibits excellent adhesive qualities,
drying out into a hard but brittle film. In view of its brittle nature when dry,
it proved unsuitable in its manufactured form as a substitute for the flexible
glue compounds employed for bookbinding operations such as gluing-off,
lining-up, perfect binding, and padding.
Experiments revealed that the addition of a softening agent or plasticizer to
the polyvinyl acetate emulsion, in an amount equivalent to 8 percent of the
total weight of emulsion, produced dry resinous films permanently flexible and
ideally suited for padding and notebook work. It was observed in the course of
this research that the addition of varying amounts of a dibutyl phthalate
plasticizer to polyvinyl acetate emulsion increased the viscosity or thickened
the padding compound in proportion to the quantity added. The increase in
viscosity was so noticeable when 10 percent of the plasticizer was added that
bookbinders who applied the adhesive to the pads complained that the compound
was too thick for easy application. The thick compound did not brush on readily
and more time was consumed in working the thick mixture. Preliminary tests made
with a padding compound of low viscosity demonstrated that a thin compound of
uniform viscosity could be more readily applied than a viscous one.
Small amounts of water were accordingly added to the plasticized polyvinyl
acetate emulsion in order to thin out the mixture sufficiently for easy
application by the bookbinder. A viscosity range lying between 5 and 7 poises
was found to be best for padding work.
A number of experiments were conducted using various chemical plasticizers in
arriving at the present formulas used in this Office but only a few of these
were found suitable in properties or of reasonable cost foruse as softening
agents. Those which best met the requirements were dibutyl phthalate, glyceryl
triacetate, sold under the trade name "Triacetin," and 2-methyl 2'4 pentanediol,
sold under the trade name "Hexylene Glycol." The incorporation of small amounts
of any of these chemicals into polyvinyl acetate emulsion produces a very good
bookbinding adhesive which remains flexible upon drying of the adhesive film.
Some advantages of polyvinyl acetate emulsion over other resinous adhesives are
that it is readily diluted with water as required by the bookbinder, it is easy
to apply, and safe to use since it contains no flammable solvents. It is also
easily washed out of brushes and containers with water while still moist. When
this plastic sets, it becomes water resistant.
The ordinary bindery glues and pastes are not satisfactory for adhering
pyroxylin treated fabrics in some bindery operations and in many instances
binders or cases glued with these adhesives pull loose or fail to remain glued
after they have dried. The white resinous polyvinyl acetate adhesive has been
found excellent for the pyroxylin treated fabrics and has been used in this
Office with complete success. This adhesive can be used for many hand operations
including gluing-off, lining-up, and the application of rides or labels. One of
the uses found for this adhesive was that of affixing oil cloth linings to
pyroxylin coated binders. The adhesive for this operation was applied by a
machine to the back of an oil cloth strip, which was then applied to the inside
of the binder. This adhesive produced a strong permanent bond between the
tumed-in edges of the pyroxylin coated film and the oil cloth. Previous
operations of this nature using hide glue as the adhesive were not satisfactory
unless the turned-in edges of the coated fabric were first washed with alcohol,
adding another operational cost to the production.
There is no necessity for the use of preservatives with this adhesive since it
does not deteriorate upon aging nor is it subject to molds or fungus growths,
even though it may be exposed to the air for many months. However, freezing
destroys the emulsion, and therefore precaution must be taken to avoid exposing
it to freezing temperatures before using.
This formula produces an adhesive which will firmly fasten paper, leather, or
such fabrics as pyroxylin treated, starch filled, rubberized, or plain muslin
cloths to cellulose acetate surfaces. It has been used in this Office in the
production of transparent cellulose acetate envelopes for the protection of
maps and photographs upon exhibition. The cloth binding used on this type of
work is glued-off by hand, permitted to dry for about two minutes, and then
applied to the cellulose acetate surfaces. In preparing this adhesive add the
water to the polyvinyl acetate emulsion and then follow with the dibutyl
phthalate and gamma valerolactone with constant stirring. Either hexylene glycol
or tri-acetin may be substituted for dibutyl phthalate as the plasticizer.
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