【国外标准】 Standard Test Method for Water Vapor Transmission Rate of Flexible Barrier Materials Using an Infrared Detection Technique (Withdrawn 2009)

The purpose of this test method is to rapidly obtain reliable values for the WVTR of barrier materials.The WVTR is an important property of packaging materials, which can be related to shelf life and product stability.In any application, the WVTR of a barrier material is determined by its permeance under the given conditions. In most cases, the WVTR will increase when the absolute humidity is increased on the wet side of the barrier and when the temperature of the environment increases, particularly if a polymeric material is the primary water vapor barrier in the construction.Values for water vapor permeance and water vapor permeability must be used with caution. The inverse relationship of WVTR to thickness and the direct relationship of WVTR to the partial pressure differential of the water vapor are not always linear.1.1 This test method covers a rapid procedure for determining the rate of water vapor transmission of flexible barrier materials in film or sheet form. This test method is applicable to sheets and films up to 3 mm in thickness, consisting of single-layer or multilayer synthetic or natural polymers and metal foils including coated materials.1.2 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.