Conservation DistList Archives [Date] [Subject] [Author] [SEARCH]

Subject: Desiccant


From: Nicholas Yeager <artifex<-a>
Date: Wednesday, August 17, 2005
Artifex Equipment, Inc., is moving towards production of its
desiccant product, called Dri-Gel, as interest in its application as
a disaster recovery option has continued to grow in the preservation
and disaster recovery fields.

The problem of drying wet books in a safe, cost-effective and
expedient fashion has plagued libraries for as long as books have
been collected. Although the field of book conservation has begun to
embrace new technologies, innovations have been slow to materialize.
Vacuum freeze-drying constitutes the most effective development to
date. This process requires that books be transported off site and
takes up to six months to complete.

In the Spring of 2003, Nicholas Yeager, CEO of Artifex Equipment,
Inc. investigated using a starch-based super absorbent polymer to
dry water damaged (damp and wet) library materials. This polymer had
been invented by the USDA's Agricultural Research Service in the
1970s and has been used in agricultural as well as industrial

Yeager and Kathleen Hayes, an information specialist at USDA's
National Agricultural Library, secured a Material Transfer Agreement
Cooperative Research and Development Agreement (MTACRADA) to develop
an interleaving product to dry books using the polymer's capacity to
soak up many times its weight in water. The resulting product
invented by Yeager and Hayes has been named "Dri-Gel" and has
patent-pending protection.

The new hydrogel desiccant makes use of the chemical polyacrylate's
ability to:

    *   absorb fifty times its weight in water
    *   release water through evaporation, and
    *   take on water and retain it under pressur--a key element
        to water removal in books

In addition to drying wet materials, Dri-Gel will have other
conservation uses.  It can be used as a poultice or humidity blanket
for relaxing brittle items because it has the ability to take on
clean water that evaporates slowly and evenly.

Dri-Gel was developed with the aid of the SBIR grant. The objectives
for this grant proposal required that the desiccant remain safely
within its enclosure, and that the product has good wet strength and
does not alter the book in any way.

Some surprising things were discovered while working out the method
of carrying the material safely into a book to dry it: * Desiccant
capacity is directly affected by proximity. The closer the desiccant
is in contact to wet material, the quicker moisture is absorbed. The
chart below describes this corollary:

    per number
    of leaves       Time required for drying
    ---------       ------------------------

    15               12 hours/ six changes
    10                5 hours/ four changes
     5              1.5 hours/three changes
     per page        10 minutes with 1.5 hours labor inserting
                     Dri-Gel sheets between leaves of the book with
                     no change of Dri-Gel

Passive moisture absorption occurs in freezers where Dri-Gel is
present. Wet books awaiting treatment are placed in a container and
frozen to avoid mold growth.  Placing Dri-Gel in the container
(often a zip-lock bag) removes 50% of the water while the item is
stored for two weeks. This lowers labor cost and drying time when
the book is finally processed

Early tests show that Dri-Gel can be used on other porous materials
that require drying such as loose paper items and works of art on

Artifex is currently fine tuning the manufacturing process of
Dri-Gel for optimal use of the desiccant and cost-effective
production methods. Dri-Gel uses environmentally friendly materials,
and is 70% biodegradable. Yeager hopes to offer the product for sale
by the end of the year.

See <URL:> or call us at

                  Conservation DistList Instance 19:12
                Distributed: Wednesday, August 31, 2005
                       Message Id: cdl-19-12-002
Received on Wednesday, 17 August, 2005

[Search all CoOL documents]