We have determined that strength characteristics of elastic strand improve when
the strand is heated. Thus, the present invention is directed to improving strength
characteristics of an elastic strand by heating the strand. The strand may be heated
by thermal conduction and/or convection, by irradiative methods using, for example,
infrared or microwave radiation, or some combination of these. If the elastic strand
is made at a location different from the location where the strand is used as a
raw material, the strand may be heated at either location, or both locations. Furthermore,
the strand may be heated in-line, i.e. as part of the process that makes the strand
or the process that uses the strand as a raw material, or off-line, i.e. in a step
separate from either of the aforementioned processes. Finally, in addition to heat
treating the strand, the strand's exposure to water or water vapor may be regulated
to reduce or eliminate strength degradation.