Interpretation of the test method of oxygen and water vapor permeability of PVDC film for food packaging

　　《GB/T 17030-2008 polyvinylidene chloride (PVDC) sheet film for food packaging was officially released in 2008 Labthink Languang is a well-known domestic enterprise specializing in the research and development of food packaging materials testing instruments There are more than 20 kinds of self-made products applied to the detection of polyvinylidene chloride (PVDC) sheet film for food packaging plastics packaging materials The products involve the resistance of packaging materials Detection of partition, mechanics, heat sealing performance, smoothness, rubbing resistance, sealing performance, thickness, heat shrinkage performance, etc In order to facilitate the majority of PVDC related enterprises and product quality supervision and inspection institutions to better understand the difference between the new standard GB / T 17030-2008 and the old standard GB / T 17030-1997, the standard changes are summarized as follows, in order to help the inspection and testing work of relevant enterprises and institutions The new standard GB / T 17030-2008 specifies the technical requirements, test methods and inspection rules of PVDC film for food packaging It is suitable for polyvinylidene chloride (PVDC) casing film for food packaging, which is made by blow molding and cut, especially for filling intestinal food The implementation of this standard means that GB / T 17030-1997 standard is officially invalid The changes of 2008 standard compared with 1997 standard are mainly reflected in two aspects: 1 The test condition of water vapor transmission of PVDC sheet casing film is changed from the original test condition B (temperature 23 ± 0.6 ° C, relative humidity 90 ± 2%) Change to condition a (temperature 38 ± 0.6 ° C, relative humidity 90 ± 2%) 2 The test method of oxygen permeability of PVDC sheet casing membrane is changed from differential pressure test to reservoir test Interpretation 1: the change of water vapor transmission test conditions will be more conducive to the development of quality inspection, which can reduce the dependence of water vapor transmission test equipment on the external environment The test equipment only needs to have the heating function to meet the temperature control requirements of product testing in the climate of the whole year In addition, the change of test conditions in this standard makes the test conditions of water vapor transmission of PVDC sheet casing film consistent with the test conditions of other plastic film materials in the food packaging industry, which plays a positive role in the unification of test conditions Interpretation 2: according to GB / T 17030-1997, the oxygen permeability test method of PVDC sheet casing film is tested by the differential pressure method specified in "GB 1038-2000 plastic film permeability test method", while the new standard GB / T 17030-2008 is changed to "GB / T 19789 packaging material" "Oxygen permeability test of plastic film and sheet" refers to the method of measuring the oxygen permeability of PVDC sheet casing film by using the constant pressure method The PVDC manufacturers and the product quality supervision and inspection organizations responsible for the safety inspection of food packaging should pay special attention to the test methods and test principles In particular, the product quality supervision and inspection institutions need to expand the use of isobaric method (coulometric method) test equipment to meet the requirements of the new standard of polyvinylidene chloride (PVDC) casing film for food packaging on the premise that they already have the air permeability test equipment by the differential pressure method (the differential pressure method meets the requirements of gas permeability test for food packaging materials other than PVDC materials) In order to meet the requirements of domestic PVDC related enterprises and legal product quality supervision and inspection institutions for oxygen transmittance testing equipment by isobaric method, "c230h oxygen transmittance testing system" developed and produced by Labthink Languang, based on the Coulomb oxygen analysis sensor and isobaric method testing principle, refer to ASTM D3985 standard is designed and manufactured to provide high-precision and high rate oxygen transmittance test for high and medium gas barrier materials, which is suitable for domestic enterprises and product quality supervision and inspection institutions In addition, GB / T The standard of polyvinylidene chloride (PVDC) film for food packaging (17030-2008) not only regulates the test of oxygen and water vapor transmission, but also specifies other test items and methods such as tensile strength and elongation at break, tear resistance, heat shrinkage, thickness, etc Labthink Languang has several intelligent electronic tensile testing machines, sly-s1 Elle Mendorf tear tester, rsy-r2 thermal shrinkage tester, chy-c2a thickness gauge and other equipment can meet the needs of professional testing The above is a brief interpretation of the new national standard GB / T 17030-2008 for polyvinylidene chloride (PVDC) sheet casing film Specific test methods, procedures, requirements and test data are not introduced here Labthink Languang hopes to use this article to introduce more communication with colleagues in the industry.