Gaskets are materials used to seal one compartment of a device ...
Gaskets are materials used to seal one compartment of a device ...
Gaskets are materials used to seal one compartment of a device ...
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equivalent basis, they <strong>are</strong> favored by manufacturers <strong>of</strong> aluminum ro<strong>of</strong> coatings.<br />
Unlike cellulose fibers,<br />
polyethylene fibers do not contain water which can<br />
react with aluminum, forming a dangerous hydrogen gas, eventually resulting in<br />
the lids <strong>of</strong> containers blowing after only six months <strong>of</strong> s<strong>to</strong>rage (Missouri<br />
Paint & Varnish 1986). To guarantee a long shelf life many manufacturers <strong>of</strong><br />
aluminum ro<strong>of</strong> coatings<br />
such as Missouri Paint & Varnish and Columbia Paint<br />
Corporation use polyethylene fiber formulations (ICF 1986). Table 3<br />
identifies some <strong>of</strong> the numerous manufacturers <strong>of</strong> polyethylene fibered ro<strong>of</strong><br />
coatings and cements.<br />
Missouri Paint & Varnish has discontinued asbes<strong>to</strong>s processing completely<br />
in 1986 and substituted it with polyethylene fibers in combination with clay<br />
and talc fillers. They estimate that aluminum ro<strong>of</strong> coatings with polyethylene<br />
fibers cost <strong>one</strong>-third more <strong>to</strong> produce than asbes<strong>to</strong>s bearing counterparts<br />
(Missouri Paint & Varnish 1986). Columbia Paint Corporation estimates that<br />
the prices <strong>of</strong> the ro<strong>of</strong> coatings and cements have increased over 25 percent as<br />
a<br />
result <strong>of</strong> their decision <strong>to</strong> reformulate their asbes<strong>to</strong>s containing products<br />
with polyethylene fibers (Columbia Paint 1986).<br />
Manufacturers <strong>of</strong> non-asbes<strong>to</strong>s ro<strong>of</strong> coatings and cements whose<br />
formulations<br />
include polyethylene fibers have indicated some problems producing the<br />
formulations.<br />
a The polyethylene fiber formulations <strong>are</strong> difficult <strong>to</strong> mix<br />
requiring other ingredients such as clay and talc;<br />
a The formulations <strong>are</strong> not as strong due <strong>to</strong> the reduced<br />
tensile strength <strong>of</strong> the fibers;<br />
a The formulations cost more <strong>to</strong> produce; and,<br />
a Their long term performance is still unknown since their<br />
life on the market has been relatively short - - 5 yrs.<br />
Many current and former asbes<strong>to</strong>s processors have encountered difficulties in<br />
replacing asbes<strong>to</strong>s formulations with polyethylene formulations in some ro<strong>of</strong>ing<br />
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