US 2018/0024011 A1 · Indicating Devices Based on Etching of Metals

Abstract

Compositions, devices and processes related to etching of a very thin layer or fine particles of a metal are disclosed for monitoring a variety of parameters, such as time, temperature, time-temperature, thawing, freezing, microwave, humidity, ionizing radiation, sterilization and chemicals. These devices have capabilities of producing a long and sharp induction period of an irreversible visual change. The devices are composed of an indicator comprising a very thin layer of a metal and an activator, e.g., a reactant, such as water, water vapor, an acid, a base, oxidizing agent or their precursors, which is capable of reacting with the said indicator. Ink formulations composed of a metal powder and a proper activator can be used for monitoring several sterilization processes, such as sterilization with steam. When water is used as an activator, a thin layer of metals, such as that of aluminum can be used as steam sterilization or humidity indicator.

Claims45

Dependent claims

An indicating system comprising a substrate having thereon:

a) a metallic material having an oxide layer on its surface;
b) optionally, an activator or its precursor;
and
c) optionally one or more polymeric binders or adhesives;
wherein the metallic material is a metal or its alloy;
the metallic material is a continuous layer or a layer of particles in a binder;
the metallic material and the activators each having its own layer or both in one layer;
the oxide layer is between the metal and the activator or its precursor when the activator or its precursor is present;
and
wherein the activator or the activator produced from its precursor is capable of destroying the metallic material and its oxide layer causing an irreversible change in opacity, reflectivity or electrical conductivity of the metallic material;
the device is capable of providing an induction period caused by the destruction of the metallic material and its oxide layer;
and
the destruction or the induction period is measured by a delay in a visual indication or a change in opacity, reflectivity or conductivity.

10 more elements

Dependencies are inferred from the claim text.

Indicating Devices Based on Etching of Metals

Life of this patent

Indicating Devices Based on Etching of Metals

Life of this patent

Abstract

Claims45