Indicator for ethylene oxide gas

• US 4,094,642 A
• Filed: 02/15/1977
• Issued: 06/13/1978
• Est. Priority Date: 02/15/1977
• Status: Expired due to Term

• Current Assignee: Dai Nippon Printing Company Limited
• Original Assignee: Dai Nippon Printing Company Limited
• Inventors: Sumimoto, Mitsuhiro, Kohama, Haruo
• Primary Examiner(s): Serwin, R.E.
• Application Number:
  US05/768,850
• Time in Patent Office: 483 Days
• Field of Search: 23/253 TP, 23/232 R, 23/254 R, 252/408, 21/DIG. 4, 116/114 AM
• US Class Current: 422/426
• CPC Class Codes: A61L 2/28 Devices for testing the effectiveness or completeness of sterilisation, e.g. indicators which change colour apparatus involving enzymes or microorganisms C12M1/34; methods involving enzymes or microorganisms C12Q1/00
• CPC Class Codes: G01N 31/226 for investigating the degree of sterilisation
• CPC Class Codes: Y10S 252/962 Temperature or thermal history

Abstract

An indicator composition for ethylene oxide gas comprises 4-(4-nitrobenzyl) pyridine, nitrocellulose, a basic substance, and, optionally, a blue coloring agent.

The indicator composition, when exposed to ethylene oxide gas, changes its color to develop a stable color indication, typically of a green color. The composition can take any shape and form, and is typically applied to a substrate such as paper to form a layer thereon.

Claims

1. An indicator composition for ethylene oxide gas which comprises 4-(4-nitrobenzyl)-pyridine, nitrocellulose, and a basic substance.

2. The indicator composition according to claim 1 which further comprises a coloring agent.

3. The indicator composition according to claim 2 in which said coloring agent is a blue coloring agent.

4. The indicator composition according to claim 1 which comprises 1 to 15 parts by weight of 4-(4-nitrobenzyl) pyridine, 12 to 25 parts by weight of nitrocellulose, and 1 to 15 parts by weight of the basic substance.

5. The indicator composition according to claim 4 which further comprises 1 to 10 parts by weight of a blue coloring agent.

6. The indicator composition according to claim 5 which further comprises 40 to 80 parts by weight of an organic solvent.

7. The indicator composition according to claim 3 in which said 4-(4-nitrobenzyl) pyridine, basic substance and blue coloring agent are encapsuled in resinous microcapsules and dispersed in said nitrocellulose.

10. The indicator composition according to claim 5 which further comprises 1 to 10 parts by weight of a plasticizer selected from the group consisting of 2,2,4-trimethyl-1,3-pentanediol-dissobutylate, castor oil, acetyl tributyl citrate and ethyl citrate.

8. An indicator composition for ethylene oxide gas which comprises 2 to 10 parts by weight of 4-(4-nitrobenzyl)-pyridine, 15 to 20 parts by weight of nitrocellulose, 2 to 10 parts by weight of a basic substance, and 1 to 10 parts by weight of a blue coloring agent.

9. The indicator composition according to claim 8 in which said basic substance is selected from the group consisting of sodium carbonate, sodium bicarbonate, sodium hydroxide, sodium oleate, sodium stearate, and calcium stearate, and said blue coloring agent is selected from the group consisting of phthalo-cyanine blue, cobalt blue, indathrene blue, and neozapon blue.

11. An indicator structure for ethylene oxide gas which comprises a substrate and a layer of indicator composition disposed on the substrate and comprising 4-(4-nitrobenzyl)-pyridine, nitrocellulose, a basic substance, and a blue coloring agent.

12. The indicator structure according to claim 11 which further comprises a resinous overcoating layer disposed over said layer of indicator composition.

13. The indicator structure according to claim 11 which further comprises a resinous undercoating layer interposed between said substrate and said layer of indicator composition.

14. The indicator structure according to claim 11 in which said layer of indicator composition comprises 2 to 10 parts by weight of 4-(4-nitrobenzyl)-pyridine, 15 to 20 parts by weight of nitrocellulose, 2 to 10 parts by weight of a basic substance, and 1 to 10 parts by weight of a blue coloring agent.

15. The indicator structure according to claim 12 in which said resinous overcoating layer is made of a thermoplastic resin selected from the group consisting of polyesters, polyamides, polyvinyl chloride, vinyl chloride/vinyl acetate copolymer, acrylic resins, polyvinylidene chloride, polyethylene, and polypropylene.

16. The indicator structure according to claim 12 in which said resinous overcoating layer is made of a thermosetting resin selected from the group consisting of unsaturated polyester resins and polyurethane resins.

17. The indicator structure according to claim 11 in which the quantity of the indicator composition on the substrate ranges from 1 to 20g-solid/m² of the area of the indicator composition.

18. The indicator structure according to claim 12 in which the quantity of the overcoating resin ranges from 1 to 20 g-solid/m² of the overcoating area.

19. The indicator structure according to claim 11 in which the substrate is a part of a structure for containing a product to be exposed to ethylene oxide gas to be indicated by the indicator composition.