US Patent 7291389 Article having temperature-dependent shape

Articles, particularly fibers, whose shape is dependent on temperature. The articles have a first component composed of a sharply-melting crystalline polymer and an overlapping second component. As the crystalline polymer is cooled through its melting range, the volume of the first component increases much more rapidly than the volume of the second component. As a result, the shape of the article changes. Such fibers can be incorporated into fibrous articles having temperature-dependent thermal insulation properties.