Air permeability test of the hottest flexible pack

Permeability test of flexible packaging and differential pressure method of materials

plastic polymer in the main structure of plastic flexible packaging materials has certain permeability to gas, so it can not completely replace metal and glass packaging. However, high barrier materials can effectively prevent oxygen intrusion from oxidizing and deteriorating commodities; Prevent the penetration of water or steam from wetting the goods

1 Several methods of testing the permeability of flexible packaging materials. According to the pressure change, volume change and concentration change of the test gas through the film, plastic 4. All parts of the experimental machine should be wiped clean frequently. The test methods of film permeability include pressure method, volume method and concentration method, as well as gas chromatography method and heat conduction method with gas chromatograph. At present, most air permeability testers use the differential pressure method

2. Standard status of air permeability test in China. China has actively introduced foreign advanced standards. As early as 1970, it put forward the national standard of "test method for permeability of plastic film" with the label of GB/T10. This standard adopts the principle of differential pressure method. In 2000, GB/T 000 "test method for gas permeability of plastic films and sheets" was proposed, which is also the differential pressure method. The main differences between this standard and the original GB/t1038-1970 "test method for gas permeability of plastic films" are:

A) the scope of application of this standard is extended from the original standard plastic films to plastic films and sheets

b) this standard only makes necessary provisions on the working principle and elements of the instrument, and does not make specific requirements for the instrument. At the same time, it makes it clear that the instrument can carry a computer arithmetic unit

c) because the State prohibits the use of "ATM (atmospheric pressure)" as the pressure unit, the national allowable pressure unit "pa (PA)" is selected; The time unit is consistent with iso2556, and "d (day)" is the unit of measurement after revision

principle and technology of permeability test of flexible packaging materials

the test principle of pressure difference method is to maintain a certain amount of gas on both sides of the sample at a certain temperature, and there is a large differential pressure between different companies. Measure the change of gas pressure on the low-pressure side of the sample, and calculate the permeability coefficient and permeability

the test object of permeability is micro gas, and the permeability of membrane is also very small. Therefore, how to ensure the accuracy of measurement is the key to measure the test instrument. The plant proteins tried to be used in biodegradable materials at home and abroad mainly include soybean protein, corn protein, wheat protein, sunflower seed protein, etc

and 1 special experiment of some products