Abstract:
The invention provides microstructured time dependent indicators including timers, time/temperature indicators, etc. The indicators are preferably highly accurate and easy to read. The invention also includes indicators which are game pieces, calendars, greeting cards, etc. The indicators function by flow of a material through channels of a microstructured substrate.
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 flow of viscoelastic indicator material between the substrate and the backing.
Abstract:
A pressure-sensitive adhesive comprises an elastomer having a partially oriented and partially crystallized elastomer component. Articles comprising the pressure-sensitive adhesive on a backing or substrate are also disclosed, as are methods of preparing the adhesive and the articles.
Abstract:
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.
Abstract:
A solvent-free hot melt process, for preparing a non-thermosettable, pressure-sensitive adhesive from a tackified non-thermoplastic hydrocarbon elastomer. The process employs a continuous compounding device that has a sequence of alternating conveying and processing zones. The processing zones masticate and mix materials in them. Non-thermoplastic elastomers having high molecular weight may be readily compounded into adhesives in the process.