Abstract: The proficiency testing project has come to an end. As a collaborative unit for this proficiency testing, Labthink is deeply aware of the important role played by this proficiency testing in the development of barrier detection in China. The results were reviewed and summarized. Keywords: barrier properties, oxygen transmission, water vapor transmission, results, summary 1. Accurately evaluate the detection level of barrier performance in China In the past, the understanding and evaluation of the level of barrier testing in China was mainly obtained through some indirect information. For example, through the market share of testing equipment of various manufacturers, the proportion of various testing methods in the domestic testing field was analyzed. Through the analysis and comparison of various test methods and the performance indicators of the equipment, the overall barrier test results in China are further judged, so the accuracy of these conclusions and evaluations is not high. In addition, because these evaluation methods are indirect and lack official authority, it is not uncommon to conduct targeted “whitewashing†of statistical data for commercial purposes. As a Class A project of the National Certification and Accreditation Administration's 2007 proficiency testing program, the participating laboratories for the verification of the barrier performance test capability of plastic packaging materials must include countries that have obtained qualification certification (metrics) and have barrier testing items. Product quality inspection center, provincial-level (including sub-provincial-level cities, cities with separate plans), product quality supervision and inspection institutes (institutions), technical centers (labs) of all directly affiliated entry-exit inspection and quarantine bureaus, relevant ministries or commissions center. Of course, corporate laboratories and other laboratories can also participate. A total of 69 laboratories participated in the oxygen transmission test, and 67 laboratories participated in the water vapor transmission test, which basically covered the quality inspection institutions and the relevant authoritative testing laboratories in most areas of China. It can be seen that the verification of the barrier performance test capability of plastic packaging materials is unprecedented in the world in terms of the scale of testing, the level of testing in participating laboratories, and the authority of organizers. Therefore, this capability verification can be used to conduct an authoritative, objective and accurate evaluation of the barrier test level in China. From the test data and laboratory data analysis, the weighing method and differential pressure method still have an unshakable position in the field of barrier testing in China, and the systematic errors of the weighing method and the differential pressure method are all within the scope of national approval. None of the laboratories using the two test methods were judged to be out of the laboratory. 2. Specification test steps The practical application of barrier testing in China is not long. Many testing organizations and laboratories have been conducting this testing business in recent years. Therefore, each tester is familiar with the test methods and the test standards. It is difficult to achieve the same level of understanding. For example, the principle of testing, the preparation and processing of samples, the choice of test environment, the impact of temperature and humidity changes on test data, the similarities and differences between test standards, and the precautions for the use of various types of test equipment (especially for non-automatic test equipment) Speaking), the depth of understanding of the testers is different. Through this proficiency test, specific testers can have a deeper understanding and understanding of these operational details, so that in the future barrier detection, the impact of these details on the test results can be better avoided. The use of barrier properties for packaging materials has been promoted and valued throughout the industry. 3. Guide the data comparison process In the past, data comparison between laboratory and barrier test methods was also carried out. However, the alignment process was not well regulated. The most prominent performance was made in the comparison of sample selection and statistical processing of test data. The work is relatively simple and not strict. Through this proficiency verification, we can clearly understand the rigorous process of the entire proficiency testing, and recognize that the consistency of the comparison between the proficiency testing and the scientific nature of the statistical analysis of the data is directly related to the accuracy of the proficiency testing work. The success or failure of the project. Therefore, the organizer of the comparison project should conduct the uniformity test and stability test of the proficiency test sample in strict accordance with the CNAS-GL03 "Guidelines for the Evaluation of Uniformity and Stability of Capability Verification Samples" to ensure that the unsatisfactory results in the proficiency test are not Due to the variability between samples and the sample itself, the test results should be statistically processed according to CNAS-GL02 "Guidelines for Statistical Processing and Capability Evaluation of Capability Verification Results", and the testing ability of participating laboratories should be evaluated according to statistical data. . These evaluation methods have been used for many years and have a profound theoretical foundation. They can lay a theoretical foundation for organizing various data comparisons in the future and become a method guide for conducting comparison work. 4. Provide reference for the selection of barrier devices There is more than one test method for each barrier index test. In fact, other test methods besides the differential pressure method and the weighing method have certain applications in China (although some methods do not have national standard support). Therefore, in this verification of capability, although the organization unit National Packaging Product Quality Supervision and Inspection Center (Jinan) recommends to participate in the laboratory to adopt GB/T1037-1988 "Plastic method for plastic film and sheet water vapor permeability test method", GB/ T1038-2000 "Plastic film and sheet gas permeability test method differential pressure method" as a test method, but also allows the use of commonly used test methods in the laboratory. Therefore, this proficiency verification provides a scientific and fair platform for data comparison of different test methods. At the same time, this capability verification considers the degree of automation of using equipment as an important factor for the first time in data comparison. In the past, we often did not pay attention to the convenience of equipment operation when comparing data between test methods. In fact, the convenience of equipment operation is directly related to the influence of human error in the test data, especially for the microscopic barrier. In the detection of indicators, the error caused by human factors may be far greater than the impact of the test method itself. Combined with the degree of automation of the equipment, this proficiency test has gained a lot of valuable conclusions. For example, for the weighing method of water vapor transmission, the test performance of the automatic weighing method and the non-automatic weighing method is completely different. Only the data issued by the laboratory using the automatic weighing method is judged as The laboratory was “suspicious,†but more than half of the data from laboratories using non-automatic weighing equipment were judged to be “suspicious†or “out of the box†in the laboratory. Senior experts are not surprised by this result, because the detection shortcomings of the past non-automatic weighing method have been mentioned many times, but some false statements often cause human error caused by the low degree of automation. The test method error is mixed. Through this proficiency test, we not only have a clearer understanding of the advantages and disadvantages of various test methods, but also provide valuable reference for various testing institutions and laboratories to purchase barrier devices in the future. Valuable information. 5. Pave the way for unifying China's barrier test data system It can be seen from this proficiency test that the data inconsistency between various barrier test methods does exist. Although the data is not very different, it sometimes leads to huge economic losses. Especially for food and pharmaceutical packaging, the difference in the test data may even lead to product safety problems. Therefore, the test method of barrier test indicators The data difference has been receiving much attention. Since the previous data comparison is small and the comparison process is not standardized, it is difficult to accurately and effectively analyze the data between various test methods through the comparison data, and the test data should be unified. The system is even more unrealistic. This capability verification is the world's first large-scale barrier detection special comparison, which not only guarantees the detection environment and test samples, but also ensures the authenticity and reliability of the test data. The statistical data of this capability verification can fully serve as the basis for the unified unified barrier test data system in the future, paving the way for the early realization of the unified data system. 6. Summary In summary, the achievements of this proficiency test are outstanding and remarkable, not only well completed the detection level of the barrier test field in China, but also realized the world's first large-scale systematically different barrier properties. The objective comparison between the test data between the test methods allows us to have a clearer understanding of some problems existing in the field of barrier detection in China, and lay the foundation for the unified unified barrier test data system.
Unbalanced development, uneven testing levels of various institutions, and inconsistent test data are the current status of material barrier performance testing in China. However, in order to change this situation and further improve the detection capability, we must first have an objective and accurate understanding of the overall situation of barrier testing in China. Through this "plastic packaging material barrier performance test - oxygen transmission and water vapor transmission test" laboratory capability verification project successfully achieved the Chinese barrier detection industry's bottom, and achieved fruitful results.