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Analysis on Purchasing Choice of High Barrier Property Material Testing Instruments

Analysis on Purchasing Choice of High Barrier Property Material Testing Instruments
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Analysis on Purchasing Choice of High Barrier Property Material Testing Instruments - 1

Analysis on Purchasing Choice of High Barrier Property Material Testing Instruments Abstract: Based on material characteristics displayed during high barrier property material transmission rate testing, this article introduces the rules and corresponding reasons for instrument choices of various methods. Keywords: high barrier property , system zero , equilibrium , sealing , temperature With the outstanding performance in packaging and growing applications in more fields, high barrier property material has become one of the main trends in packaging material R&D worldwide. Correspondingly, the R&D and manufacturing of high barrier property materials have put forward higher requirements for testing instruments. It’s commonly believed, by operators, that data fluctuations of high barrier property materials would be greater than those of medium and low barrier property materials. What are the causes for such data fluctuations? What are the requirements for high barrier property material testing instruments? Based on the material characteristics displayed during high barrier property material transmission rate testing, this article introduces rules and corresponding reasons for instrument choice. 1. Testing Characteristics of High Barrier Property Materials High barrier property material, also called low transmission rate material, is the material with low gas transmission rate. When testing barrier property of such materials, three testing characteristics would be observed as follows: 1.1 High barrier property materials are extremely low in gas transmission quantity and extremely slow in transmission speed. This is the operational difficulty when testing high barrier property materials, which put forward two corresponding requirements for testing instruments: on one hand, the instruments should have excellent sealing performance. With years of testing experiences, it’s admitted that leakage is the greatest obstacle when testing high barrier property materials. It should also be noted that such leakage is often not a problem of testing instruments, but a problem caused by improper specimen clamping. On the other hand, the detecting sensor should be of high precision and high sensitivity. The sensor precision determines testing limit directly, and is the main decisive factor for testing time. 1.2 It would take a long time to reach transmission equilibrium. Equilibrium is the key in barrier property determination. As to high barrier property materials, it would accumulate for a period of time for the transmitted testing gases to be detected by the sensor. Besides, data fluctuations and errors caused by minority of gas quantity would influence judgment for transmission equilibrium. Generally, it would take several hours up to less than 20 hours to reach equilibrium for high barrier materials. The ambient factors and corresponding interference cannot be neglected. For instance, the influence of temperature should not be ignored for both sensor and specimen: temperature fluctuations would lead to fluctuations of sensor output as well as barrier property changes of the specimens. Moreover, the long testing time would lead to compositional change of testing gases, including minor gas quantity changes and the under-mixing of mixed gases caused by gas source change. Therefore, compositional stability of testing gases should be www.labthinkinternational.com.cn

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Analysis on Purchasing Choice of High Barrier Property Material Testing Instruments - 2

guaranteed. 1.3 There are higher requirements for system zero and testing process stability. System zero is the comprehensive expression and the recorded instrument status when the residual testing gas inside instrument has been cleared to the utmost. When testing low barrier property materials, system zero is not so much influential to the testing data. It’s because that the system zero value, compared to the barrier value, can be omitted. As to high barrier property materials, accuracy of system zero would directly influence testing data. Besides, fluctuation caused by temperature would...

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Analysis on Purchasing Choice of High Barrier Property Material Testing Instruments - 3

purchasing equal pressure instruments, the following points should be noticed: 2.2.1 Lower testing limit 2.2.2 Control and monitor capability of the ambient environment. Since gas circuit of equal pressure instrument is exposed to the ambient environment, the interferences of environmental factors can not be neglected. Therefore, control and monitoring of the ambient environment should be especially noticed. 2.2.3 Gas source handling. During equal pressure testing process, a large amount of testing gas purges into the two chambers separated by the specimen. The changing of carrier gas...

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Analysis on Purchasing Choice of High Barrier Property Material Testing Instruments - 4

144 Wuyingshan Road, Jinan, P.R.China The above mentioned information would contribute to the instrument purchase of high barrier property material testing. Furthermore, specific testing procedures should be taken care. For example, gas source, specimen sealing, prolonging vacuuming time or purging zero time, and environmental factors, etc., should all be taken into consideration. Some faulty views caused by immature testing technologies of the early stage should be corrected. At present, there is no remarkable difference between those barrier property testing methods.

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