Rapid oxygen absorption by using activators

• US 6,616,861 B1
• Filed: 09/28/2000
• Issued: 09/09/2003
• Est. Priority Date: 10/01/1999
• Status: Expired due to Term

• Current Assignee: Pactiv
• Original Assignee: Pactiv
• Inventors: Evans, Susan P., Sloan, R. Andrew, Santhanam, Kalathur S. V., Luthra, Vinod K.
• Primary Examiner(s): ANTHONY, JOSEPH DAVID
• Application Number:
  US09/676,274
• Time in Patent Office: 1,076 Days
• Field of Search: 252/188.28, 252/181.3, 252/181.4, 252/191, 426/124, 426/118
• US Class Current: 252/188.28
• CPC Class Codes: A23L 3/3436 Oxygen absorbent
• CPC Class Codes: C09K 15/326 containing only metals

Abstract

Absorbing oxygen from a closed space at a rapid rate, particularly in food packaging, is made possible by introducing an alcohol-water mixture as an activator for iron-based absorber systems, preferably including an acid to control pH. Preferred alcohols are aliphatic alcohols, particularly, monohydric alkanols, such as methanol, ethanol, n-propanol, isopropanol, sec-butanol and t-butanol. Such absorber-activator combinations are capable of rapidly reducing the oxygen in a closed package. A preferred acid is orthophosphoric acid used in an amount sufficient to establish a pH of about 0.6 to 4. A preferred iron-based absorber system employs sponge iron, optionally including a dibasic acid cooperating with the orthophosphoric acid to control pH in the system. In one preferred embodiment, the iron-based absorber is pre-activated by contacting with the activator in the substantial absence of oxygen for a predetermined period of time.

Claims

1. An oxygen-absorbing composition comprising sponge iron, optionally including water absorbing materials, carbon dioxide generating compounds and salts, and as an activator 2-10 vol. % isopropanol and 90-98 vol. % orthophosphoric acid in water to provide a pH of about 0.5 to 5.