초록 ▼

A selectively activated time-temperature integrating device for providing a visually observable indication of cumulative thermal exposure, in which a viscoelastic material migrates into a diffusely light-reflective porous matrix at a rate which varies with temperature to progressively change the lig

A selectively activated time-temperature integrating device for providing a visually observable indication of cumulative thermal exposure, in which a viscoelastic material migrates into a diffusely light-reflective porous matrix at a rate which varies with temperature to progressively change the light transmissivity of the porous matrix and thereby provide the visually observable indication. The viscoelastic material can comprise a pressure sensitive adhesive. The visually observable indication can comprise latent indicia which initially are not visible and become visible, obscurable indicia which initially are visible and become obscured, or a combination of both. Various actuating means for selectively switching the indicator from an unactivated state to an activated state are described. Also disclosed are a method for providing a visually observable indication of cumulative thermal exposure and a method for providing a time and temperature integrating device for providing a visually observable indication of cumulative thermal exposure of an object.

대표청구항 ▼

A time and temperature integrating device for providing a visually observable indication of cumulative thermal exposure, said device comprising: a) a first substrate comprising a first side and a second side, said second side including a diffusely light-reflective porous matrix, wherein said porous

A time and temperature integrating device for providing a visually observable indication of cumulative thermal exposure, said device comprising: a) a first substrate comprising a first side and a second side, said second side including a diffusely light-reflective porous matrix, wherein said porous matrix includes an exposed surface; b) a first backing comprising a first surface and a second surface, wherein said first surface of said backing includes a viscoelastic material disposed thereon, and wherein said viscoelastic material includes an exposed surface; and c) actuating means for selectively switching said device from an unactivated state to an activated state; wherein when said device is in said unactivated state, said viscoelastic material is substantially out of contact with said porous matrix; wherein when said device is in said activated state, said actuating means maintains said exposed surface of said viscoelastic material and said exposed surface of said porous matrix in substantial contact with one another such that said viscoelastic material progressively migrates into said porous matrix at a rate which increases with increasing temperature; and wherein migration of said viscoelastic material into said porous matrix progressively increases the light transmissivity of said porous matrix to provide said visually observable indication of cumulative thermal exposure.