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US 2010/0247900 A1Published application
Thermochromic indicator
AssigneeLandec Corporation
InventorsRobert Parker, Julian E. Schafer, Steven P. Bitler
Life of this patent
Estimating the term…
Abstract
A thermochromic indicator includes a coating on the substrate. The coating comprising a solid crystalline particles having a melting point of 0-130° C. At temperatures below the melting point, the coating is opaque. At temperatures above the melting point, the coating becomes translucent. The change in opacity can be reversible or irreversible.
Claims20
A thermochromic indicator which comprises
- (1) a substrate, and
- (2) a coating on the substrate, the coating comprising particles which
- (a) comprise a solid side chain crystalline (SCC) polymer having a Tp of 0-105° C. and an onset of melting point, To, such that (Tp−To) is less than Tp0.6,
- (b) when the coating is a temperature below Tp, have a particle size such that the coating has opacity resulting from the scattering of visible light, and
- (c) when the coating is heated from a temperature below Tp to a temperature above Tp, melt and thus decrease the opacity of the coating.
2 more elements
7-12. (canceled)
A thermochromic indicator which comprises
- (1) a substrate, and
- (2) a coating on the substrate, the coating comprising crystalline particles, air voids and a translucent non-crystalline binder in which the particles are dispersed, the binder being present in amount 5-40% by weight of the coating, and the particles being present in amount 60-90% by weight of the coating, wherein the crystalline particles
- (a) comprise a solid crystalline material having a crystalline melting point, Tp, of 0° C.-130° C.,
- (b) have a particle size such that, when the coating is a temperature below Tp, the coating has opacity resulting from the scattering of visible light, and
- (c) when the coating is heated from a temperature below Tp to a temperature above Tp, melt and thus decrease the opacity of the coating.
2 more elements
A thermochromic indicator which comprises
- (1) a substrate, and
- (2) a coating on the substrate, the coating being at least 1 mm thick, and comprising crystalline particles and a translucent, noncrystalline, continuous matrix polymer in which the particles are dispersed, the matrix polymer being present in amount 40-65% by weight of the coating, wherein the crystalline particles
- (a) comprise a solid crystalline material having a crystalline melting point, Tp, of 0° C.-130° C.,
- (b) have a median particle size, p, of 0.3-2μ such that, when the coating is a temperature below Tp, the coating has opacity resulting from the scattering of visible light, and
- (c) when the coating is heated from a temperature below Tp to a temperature above Tp, melt and thus decrease the opacity of the coating.
2 more elements
Dependencies are inferred from the claim text.