Article having temperature-dependent shape
AssigneeLandec Corporation
InventorsSteven P. Bitler, Edward E. Schmitt, Quiang Zheng
Life of this patent
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Abstract
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.
Claims18
An article comprising
- (1) a first component composed of a first polymeric composition, the first polymeric composition comprising a side chain crystalline polymer which has
- (a) a peak melting temperature Tp which is −20 to 40° C.,
- (b) an onset of melting temperature To such that (Tp−To) is less than
- (−1.7757e−5)×(Tp3)+(3.339e−3)×(Tp2)−(6.977e−2)×(Tp)+k,
- where k is 16, and
- (c) a heat of fusion of at least 5 J/g;
- and
- (2) a second component which
- (a) is composed of a second composition, and
- (b) overlaps the first component;
- the first polymeric composition having a volume expansion between To and Tp which is greater than the volume expansion of the second composition over the same temperature range, and the first and second components having dimensions and shapes such that the article, in the absence of external restraint, changes shape when it is heated from Toto Tp and when it is cooled from Tp to To.
A fibrous mass comprising a plurality of fibers each of which comprises
- a first component composed of a first polymeric composition, the first polymeric composition comprising a side chain crystalline polymer which has
- (a) a peak melting temperature Tp which is −20 to 40° C.
- (b) an onset of melting temperature To such that (Tp−To) is less than
- (−1.7757e−3)×(Tp3)+(3.339e−3)×(Tp)−(6.977e−2)×(Tp)+k,
- where k is 16, and
- (c) a heat of fusion of at least 5 J/g;
- and
- a second component which
- (a) is composed of a second polymeric composition, and
- (b) overlaps the first component;
- the first polymeric composition having a volume expansion between To and Tp which is at least 5 times the volume expansion of the second composition over the same temperature range, and the first and second components having dimensions and shapes such that the fibrous mass, in the absence of external restraint, changes shape when it is heated from To to Tp and when it is cooled from Tp to To.
Dependencies are inferred from the claim text.