MVTR stands for "Moisture Vapor Transmission Rate (http://www.protectivepackaging.net/
How is moisture resistance measured?
Moisture resistance is measured in a special chamber where it is divided vertically by the substrate/barrier material. A dry atmosphere is in one chamber, and a moist atmosphere is in the other. A 24-hour test is run to see how much moisture passes through the substrate/barrier from the "wet" chamber to the "dry" chamber. Standard test procedures (TAPPI T-464, ASTM E96) can specify any one of five combinations of temperature and humidity in the "wet" chamber. The toughest conditions are 100°F / 95%RH (Relative Humidity).
Currently, the best barrier material on the market today has an MVTR (http://www.protectivepackaging.net/
Protective Packaging specializes in protecting products, equipment, and machinery from corrosion, electrostatic discharge, contaminants, ultraviolet rays and dust during shipping and storage. Our corrosion protection products and services consist of: anti-static and static shielding bags, flexible packaging materials, moisture barrier bags, Mil-Spec (military specified) packaging materials, volatile corrosion inhibitors (http://www.protectivepackaging.net/
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