Air permeability test and control of the hottest p

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The permeability test and control of packaging materials

the entrance is also low. The research on the permeability of packaging materials is particularly important in the pharmaceutical and food industries, which directly affects the quality of products. Single film cannot meet the overall demand of flexible packaging. In recent years, multi-layer composite do not drop film is widely used in various fields with its excellent barrier property, chemical resistance and other advantages, among which barrier layer materials play a key role

different packages have different requirements on the permeability of materials. In the food industry, the most important barrier is oxygen permeability, which is generally classified as (taking oxygen permeability as an example) cm3/m2? atm? 24h is called high barrier, which is mainly used in the packaging of milk, fresh-keeping film, special drugs, etc., cm3/m2? atm? Medium barrier within 24h, mainly used in general food bags, 200cm3/m2? atm? Over 24h is low barrier, which is mainly used in special packaging without any requirements and requiring cooking and disinfection. The comparison of air permeability test equipment and methods on the market is as follows

1 International testing methods can also win more escape time for people, including concentration difference method, pressure difference method, etc

2. International brands of breathers include American makon, Danish PBI, Japan Toyo precision machine, etc. their calibration instruments generally use reference materials, and the storage requirements of reference materials are extremely strict, so it is difficult to calibrate. According to a large number of test data, the comparability of test results between instruments is not strong due to the difficulty of calibration, and the test time is long and the price is high

3bty-b1 permeability tester adopts high-precision sensing equipment micro differential pressure transmitter, adopts eddy current principle to avoid the use of silicone oil, safe operation, avoids the shortcomings of traditional vacuum leakage, and the price is moderate. And the pressure calibrator is used for calibration, which is intuitive, accurate and convenient

the test method discussed below (permeability tester as an example) adopts the pressure difference method. The test principle is to maintain a certain gas pressure difference on both sides of the sample at a certain temperature, measure the gas pressure change measured at low pressure of the sample, and calculate the permeability coefficient and permeability. The specific steps are as follows:

1 sample and pretreatment

1.1 the diameter of the sample is 75mm

1.2 the sample has no wrinkles and the surface is clean

1.3 three samples in each group

1.4 samples are dried in anhydrous calcium chloride dryer for 24h, or treated according to the product standard

2 test conditions

2.1 temperature: 25 ± 2 ° C or as specified in the product standard

2.2 pressure: the pressure difference between the upper and lower chambers is 1atm

2.3 the type of gas is selected according to the use requirements and needs to be dried. O2, N2 or other gases

3 test steps

3.1 measure the thickness of the sample, measure at least 5 points, and take the arithmetic mean value

3.2 place the sample on the coarse filter paper (diameter 66mm), seal it in the ventilation chamber, and start the automatic test of the whole process of the test. After that, pop up the permeability tester report

4. The test data of permeability can be used to guide the production of packaging film

4.1 the components of packaging film can be selected, including basic resins such as LDPE, LLDPE, PP, BOPP, PE, etc.

4 tablet pressing 2. Barrier coating materials such as EVOP, PA and PVDC can be selected; PVDC is the only high barrier transparent material approved by FDA to contact with food. Taking BOPP as an example, the oxygen permeability is reduced by 1000 times after coating

4.3 the process research of barrier coating can be carried out, which can be single-sided, double-sided, or multi-layered as required. Or choose coating methods, such as vacuum aluminum plating, physical or chemical deposition coating silicon oxide, etc

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