Gas sensing element and methods of making the same

Patent metadata

Field	Value
Publication number	US-10845314-B2
Application number	US-201816070610-A
Country	US
Kind code	B2
Filing date	Feb 16, 2018
Priority date	Feb 17, 2017
Publication date	Nov 24, 2020
Grant date	Nov 24, 2020

Abstract

A gas sensing element includes a gas detection layer including a chemochromic pigment, with modifications towards enhancing shelf-life performance and false detection performance before use. The gas detection layer has an adhesion of greater than or equal to 0.2 N/25 mm. Also described are methods of making the aforedescribed element to attain enhanced shelf-life performance and false detection performance.

First claim

The invention claimed is:

1. A gas sensing element comprising:
a gas detection layer including a pigment,
wherein the gas detection layer includes a silicone-based pressure sensitive adhesive that has an adhesion of greater than or equal to 0.2 N/25 mm,
wherein the silicone-based pressure sensitive adhesive includes a polymer of siloxane having at least a methylphenylsiloxy group or a dimethylsiloxy group, and
wherein the pigment includes a chemochromic composition such that the chemochromic composition is dispersed within the polymer of siloxane and, upon the gas detection layer being pressed against a target other than the gas sensing element itself, the gas sensing element is adhered to the target by the adhesion of the silicone-based pressure sensitive adhesive.

2. The gas sensing element of claim 1 , wherein the pigment irreversibly changes in color, by contacting reducing gas.

3. The gas sensing element of claim 1 , the element further comprising carrier particles having a surface, the pigment including a palladium oxide, palladium hydroxide, or palladium salts on the surfaces of carrier particles.

4. The gas sensing element of claim 3 , wherein a noble metal other than palladium is supported or loaded, on the surfaces of the carrier particles.

5. The gas sensing element of claim 3 , wherein the carrier particles include titanium oxide.

6. The gas sensing element of claim 1 , further comprising:
a backing material.

7. The gas sensing element of claim 6 , wherein the backing material includes polyimide; polyethylene; fluoro carbon polymer such as fluorinated ethylene propylene copolymer (FEP), ethylene tetrafluoroethylene copolymer (ETFE), poly tetra fluoro ethylene (PTFE), or tetra fluoro ethylene hexa fluoro propylene copolymer (PFA); or polyethylene terephthalate (PET) which contains UV absorber or hindered amine light stabilizers (HALS).

8. The gas sensing element of claim 1 , wherein the gas sensing element is rolled up into a bundle roll-shape.

9. The gas sensing element of claim 1 , wherein, in a manufacturing process, the gas detection layer is exposed to an oxygen-containing atmosphere.

10. The gas sensing element of claim 1 , wherein the gas detection layer has a release liner on a finished product or on a product that is in process of production.

11. A method for producing the gas sensing element of claim 1 , the method comprising:
(1) contacting a treatment liquid and the chemochromic composition, the treatment liquid comprising a siloxane precursor and an initiator; and
(2) heating the treatment liquid to a temperature sufficient to activate the initiator so that the precursor is crosslinked to create the gas detection layer.

12. The method of claim 11 , where the chemochromic composition comprises one or more palladium-oxide-based chemochromic elements.

13. The method of claim 12 , wherein the gas sensing element includes backing that is resistant to ultraviolet radiation.

14. The method of claim 12 , further comprising the step of exposing the gas detection layer to an oxygen-containing atmosphere.

15. The method of claim 14 , wherein the step of exposing the gas detection layer to an oxygen-containing atmosphere comprises using an oxygen permeable release liner.

Assignees

• Nitto Denko Corp

Inventors

• Nakamura Koichi
• Mohajeri Nahid
• Chen Yu-Chu
• Bizati Kujtim
• Inokuchi Shinji

Classifications

• G01N33/005 Primary

  H2 · CPC title

• G01N31/223 Primary

  for investigating presence of specific gases or aerosols (G01N31/221, G01N31/222 take precedence; actuation of fire alarm by presence of smoke or gases G08B17/10) · CPC title

• G01N21/783 Primary

  for analysing gases · CPC title

• G01M3/22

  for pipes, cables or tubes; for pipe joints or seals; for valves; {for welds; for containers, e.g. radiators} · CPC title

• G01D7/00

  Indicating measured values · CPC title