Gaskets are materials used to seal one compartment of a device ...

mineral. Hence, manufacturers have been forced to replace asbestos with a
combination of substitute materials, including cellulose, polyethylene, and
ceramic fibers, and clay, talc, wollastonite, calcium carbonate (limestone)
and silica gel thickeners (ICF 1986; Krusell and Cogley 1982). The substitute
products can be grouped into three major categories according to the type of
non-asbestos
substitute used:
a cellulose fiber mixtures,
a polyethylene fiber mixtures, and
a other mixtures (ICF 1986). -
The current market share of the different substitute formulations is
presently unknown and our attempt
an asbestos ban relies more on the
to project the market shares in the event of
informed judgement of industry experts
rather than hard numbers.
Industry has indicated that asbestos-free roof
coatings and cements account for between 20 and 50 percent of the market
today. Nevertheless, it is evident from the survey that the market share of
asbestos-free roofing products is
increasing rapidly as more and more
companies replace asbestos. In an effort to gain a portion of the growing
non-asbestos market, many manufacturers price their non-asbestos formulations
the same as the traditional asbestos-containing products, even though
non-asbestos formulations cost from 2 to 37 percent more to produce (ICF
1986).
The description of substitute mixtures is divided into two parts: a
description of the fiber replacing asbestos (section a), followed by a
description of the roof coatings and cements
formulations made using that
fiber
(section b).
1. Cellulose Fiber Mixtures
a. Cellulose Fibers
Cellulose fibers are
generally milled from recycled or unused
newsprint in the presence of such additives as kaolin clay, calcium carbonate,
-5-