Carbon dioxide sensitive material

• US 5,849,594 A
• Filed: 05/16/1997
• Issued: 12/15/1998
• Est. Priority Date: 12/19/1994
• Status: Expired due to Fees

• Current Assignee: Sealed Air Limited (Sealed Air)
• Original Assignee: Sealed Air Limited (Sealed Air)
• Inventors: Mills, Andrew, Monaf, Lela Margaret, Whitwood, Robert John, Balderson, Simon Neville
• Primary Examiner(s): ALEXANDER, LYLE
• Application Number:
  US08/836,910
• Time in Patent Office: 578 Days
• Field of Search: 422/58, 422/61, 422/83-88, 436/2, 436/133-134, 128/205.28, 73/23.3
• US Class Current: 436/133
• CPC Class Codes: G01N 31/223 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 Class Codes: Y10T 436/204998 Inorganic carbon compounds

Abstract

A carbon dioxide sensitive material including a polymer binder, a plasticiser, a lipophilic organic quaternary cation, an indicator dye anion and an aromatic alcohol in such concentration that the material changes color in accordance with the concentration of carbon dioxide.

Claims

1. A carbon dioxide sensitive material comprising, in admixture, a polymer binder, a plasticiser, a lipophilic organic quaternary cation, an indicator dye anion and an aromatic alcohol in such concentration that the material changes colour in accordance with concentration of carbon dioxide.

2. The material as claimed in claim 1 wherein the aromatic alcohol is selected from the group consisting of 2,4-dichlorophenol, 2-ethylphenol, 2-chlorophenol, 3-chlorophenol, 2-ethoxyphenol, phenol, resorcinol, m-cresol, p-cresol, o-cresol, napthol, 2,6-dimethylphenol, 3,5-dimethylphenol, a butylated reaction product of p-cresol and dichloropentadiene, and mixtures thereof.

3. The material as claimed in claim 1 wherein the indicator dye anion is m-cresol purple, cresol red, phenol red or a mixture thereof.

4. The material as claimed in claim 1 wherein the indicator dye is adapted to exhibit a plurality of colours, each colour of which is indicative of a specific concentration of carbon dioxide.

5. A method for indicating directly the condition of a packaged product comprising exposing the carbon dioxide sensitive material of claim 1 to carbon dioxide in a package containing the product.

6. A method for indicating the concentration of carbon dioxide in a modified atmosphere package comprising exposing the carbon dioxide sensitive material of claim 1 to carbon dioxide in a modified atmosphere package.

7. A method for indicating the concentration of carbon dioxide in a package comprising the steps of:

depositing the carbon dioxide sensitive material of claim 1 on a micro-porous substrate; and

sealing the micro-porous substrate to an inner surface of a package.

8. A package material adapted for use in modified atmosphere packaging, said package material having affixed thereon a microporous substrate, upon which is deposited the carbon dioxide sensitive material of claim 1.

9. A modified atmosphere package defined at least in part by a package material and comprising a modified atmosphere, a product exposed to said modified atmosphere, and the carbon dioxide sensitive material of claim 1 deposited on a microporous substrate and contained within or on said package material so as to contact said modified atmosphere.

10. The material as claimed in claim 1 wherein the plasticiser is selected from the group of compounds comprising adipates, phthalates and phosphates so as to determine, in use, reaction speed, sensitivity of the material to temperature and sensitivity of the material to changes in concentration of carbon dioxide.

11. The material as claimed in claim 10 wherein the plasticiser is either di-isodecyl adipate, di-isoctyl adipate, di-ethylhexyl adipate, di-(C7-9-alkyl) adipate, butylbenzyl phthalate, 2-ethylhexylbenzyl phthalate, benzyl phthalate, dimethyl phthalate, 2-ethylhexyldiphenyl phosphate, isodectyl phosphate, tributyl phosphate, tritolyl phosphate, tris-2-ethyl phosphate, castor oil or a mixture thereof.