Time-temperature integrating indicator device with barrier material
First Claim
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1. A time-temperature integrating indicator device for providing a visually observable indication of the cumulative thermal exposure of an object, said device comprising:
- (a) a substrate having a diffusely light-reflective porous matrix; and
(b) a backing including on its surface a viscoelastic indicator material for contacting said porous matrix, and a barrier material for substantially inhibiting the lateral and longitudinal flow of viscoelastic material regardless of whether the indicator device is in an activated state or unactivated state;
wherein the device is in the unactivated state when the viscoelastic indicator material is out of contact with the porous matrix; and
wherein the device is in the activated state when the viscoelastic indicator material is in contact with the porous matrix such that the viscoelastic indicator material migrates into the porous matrix at a rate that increases with increasing temperature, thereby creating a visually observable indication of cumulative thermal exposure.
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Abstract
A time-temperature indicator device provides a visually observable indication of the cumulative thermal exposure of an object. The device includes a substrate having a diffusely light-reflective porous matrix and a backing. The backing includes on its surface a viscoelastic indicator material for contacting the substrate and a barrier material for substantially inhibiting the lateral and longitudinal flow of viscoelastic indicator material between the substrate and the backing.
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Citations
30 Claims
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1. A time-temperature integrating indicator device for providing a visually observable indication of the cumulative thermal exposure of an object, said device comprising:
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(a) a substrate having a diffusely light-reflective porous matrix; and
(b) a backing including on its surface a viscoelastic indicator material for contacting said porous matrix, and a barrier material for substantially inhibiting the lateral and longitudinal flow of viscoelastic material regardless of whether the indicator device is in an activated state or unactivated state;
wherein the device is in the unactivated state when the viscoelastic indicator material is out of contact with the porous matrix; and
wherein the device is in the activated state when the viscoelastic indicator material is in contact with the porous matrix such that the viscoelastic indicator material migrates into the porous matrix at a rate that increases with increasing temperature, thereby creating a visually observable indication of cumulative thermal exposure. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method of providing an indication of the cumulative thermal exposure of an object, comprising the steps of:
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(a) providing a time-temperature integrating indicator device comprising;
(i) a substrate having a reflective porous matrix; and
(ii) a backing including on its surface a viscoelastic indicator material for contacting said porous matrix, and a barrier material for substantially inhibiting the lateral and longitudinal flow of viscoelastic indicator material regardless of whether the indicator device is in an unactivated state or an activated state, wherein the device is in the unactivated state when the viscoelastic indicator material is out of contact with the porous matrix, and wherein the device is in the activated state when the viscoelastic indicator material is in contact with the porous matrix such that the viscoelastic indicator material migrates into the porous matrix at a rate that increases with increasing temperature, thereby creating a visually observable indication of cumulative thermal exposure;
(b) activating said device by placing said viscoelastic indicator material in contact with said porous matrix such that said viscoelastic indicator material migrates into said porous matrix at a rate which increases with increasing temperature and creates a visually observable indication of cumulative thermal exposure; and
(c) mounting the device on an object whose cumulative thermal history is to be measured. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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23. A striped viscoelastic indicator tape for use in a time-temperature integrating indicator device having a substrate with a diffusely light-reflective porous matrix, said device for providing a visually observable indication of the cumulative thermal exposure of an object, said indicator tape comprising:
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(a) a backing material;
(b) a viscoelastic indicator material on a portion of the surface of the backing material, capable of penetrating the porous matrix at a rate that increases with increasing temperature; and
(c) a barrier material on a portion of the surface of the backing material for substantially inhibiting the lateral and longitudinal flow of viscoelastic indicator material between the backing and another surface when the device is in an unactivated state, wherein the device is in the unactivated state when the viscoelastic indicator material is out of contact with the porous matrix. - View Dependent Claims (24, 25, 26, 27, 28, 29, 30)
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Specification