Gas-permeable membrane

US6376032B1 · kind B1 · utility

Assignee

• Landec Corporation · US

Inventors

• Raymond Clarke · Los Altos, US
• Ray F. Stewart · Redwood City, US
• Valentine Y. Yoon · Lompoc, US
• Donald A. Schultz · San Jose, US
• Bradley Marshall McClary · Moorpark, US

Key dates

• Filing date: Dec 5, 1996
• Grant date: Apr 23, 2002
• Expiry date: Dec 5, 2016

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10T428/31935
• WIPO field: Handling
• WIPO sector: Mechanical engineering

Abstract

Novel gas-permeable membranes which are particularly useful in the packaging of fresh cut fruit and vegetables, and other respiring biological materials. The membranes have an O2 permeability of at least 775,000 ml/m2.atm.24 hrs, a P10 ratio of at least 1.3, and a ratio of CO2 permeability to O2 permeability (R) of at least 1.5, and are made by forming thin polymeric coatings on microporous polymeric films. Preferred coating polymers are side chain crystalline polymers. Preferred microporous films contain inorganic fillers, particularly such films based on ultrahigh molecular weight polyetheylene or polypropylene. FIG. 1 illustrates how O2 permeability an R ratio vary for different coating polymers and microporous films.