Testing Oxygen Permeability of Potato Chips Aluminized Composite Film Packaging Before and After Flex

JINAN, CHINA, 2020-Aug-06 — /EPR Network/ —

1、Significance

Potato chips have high oil content. When meeting high concentration of oxygen, the oil is easy to be oxidized, resulting in deterioration in taste of the potato chips. In order to reduce the amount of oxygen in the environment penetrating into the packaging of potato chips, food enterprises generally choose aluminum-plated composite film with high barrier for packaging. Aluminum coating composite film refers to the evaporation of aluminum on one of the single-layer films. The presence of metal aluminum increases the overall barrier performance of the material, but also leads to the poor flex resistance of the material. When the material is rubbed by external forces, the aluminum coating evaporated is easy to form crack, creases, pinholes, etc., causing the overall barrier and physical and mechanical properties of the package to decline, and fails to realize its designed function, which will make the chips in the shelf lifeless crispy and taste bad. Therefore, through the detection and comparison of barrier performance before and after flex of aluminum coated composite film packaging, the flex durability of packaging can be effectively controlled to prevent the above quality problems caused by poor flex durability of packaging materials.

2、Standard

The domestic test methods for oxygen permeability of soft plastic composite film materials are coulometric method (i.e. isobaric method) and differential pressure method. The reference standards are respectively GB / T 1038-2000  Plastics-Film and sheeting-Determination of gas transmission-Differential-pressure method and GB / T 9789-2005  Packaging material.- Test method for oxygen gas permeability characteristics of plastic film and sheeting – Coulometric sensor. The reference standard in this paper is GB / T 1038.

At present, there is no testing standard for packaging flex durability in China. In this paper, ASTM f392 Standard Test Method for Flex Durability of Flexible Barrier Materials is used to simulate the kneading and bending damage of aluminum composite film in the process of production, processing and transportation.

3、Sample

The packaging of potato chips with aluminized composite film provided by a food enterprise.

4、Test instrument

The FDT-02 Flex Durability Tester and VAC-V2 Differential Pressure Gas Permeability Tester independently developed and designed by Jinan Labthink Instruments Co., Ltd.

 

4.1 Test Principle

In this paper, the change of the barrier properties of the sample before and after flex is tested to determine the flex durability of the material. The test principle of oxygen permeability is to place the pre-treated sample between the upper and lower test chambers and clamp it. First, vacuum the low-pressure chamber (lower chamber), and then vacuum the whole system; when the specified vacuum degree is reached, close the lower chamber for testing, fill the high-pressure chamber (upper chamber) with a certain pressure of test gas, and ensure that a constant pressure difference (adjustable) is formed on both sides of the sample; in this way, the gas will permeate from the high-pressure side to the low-pressure side under the effect of the pressure gradient. By monitoring the pressure in the low pressure side, the barrier parameters of the tested sample can be obtained.

5、Test process

(1) Sample preparation process

Use a sampler to cut 3 pieces of Φ 97 mm specimens from the aluminum coated composite film sample of potato chips, and test the oxygen permeability.

In addition, take the sample of aluminum-plated composite film of potato chips, cut three 280 mm long and 200 mm wide specimens, fix the sample on the FDT-02 Flex Durability tester with 10-12 mm wide pressure-sensitive double-sided tape, and select the appropriate flex mode for the test. Use the sampler to cut 3 pieces of Φ 97 mm specimens on the flex sample, and test the oxygen permeability.

(2) The three specimens before flex were mounted respectively in the test chamber of VAC-V2 differential pressure gas permeability tester for testing.

(3) The parameters such as sample name, sample thickness, test temperature, test humidity, etc. are set on the differential pressure gas permeability tester.

(4) Start the vacuum pump.

(5) Click the “start test” option to start the test, and the instrument will automatically calculate and display the test results.

(6) After flex, the three samples were tested according to the steps of (2) ~ (5), and the changes of the average oxygen transmission rate before and after flex were compared.

6、Test result

In this paper, the average oxygen transmittance of the sample before flex is 0.4712 cm³/(m²·24h·0.1MPa), and after flex is 23.4785 cm³/(m²·24h·0.1MPa).

7、Conclusion

Through the above results, it can be seen that the oxygen permeability of the composite film after flax are obviously increased, and the oxygen barrier properties decreased. By increasing the composite fastness between the aluminized layer and its substrate film, increasing the thickness of the aluminized layer and other measures, the flex durability of the aluminized composite film can be improved, and the change of oxygen transmission rate before and after the flex of the aluminized composite film can be controlled timely. VAC-V2 differential pressure gas permeability tester is a professional oxygen permeability tester used to test the oxygen barrier properties of film and sheet. It has the advantages of simple operation, high test accuracy and good repeatability. Combined with FDT-02 Flex durability tester, it can be used to accurately evaluate the flex durability of packaging materials.

Jinan Labthink Instruments Co., Ltd is dedicated to providing customers with packaging testing solutions and helping the manufacturers to reach their goals of quality and safety assurance through improvement of packaging testing techniques and development of high-end packaging testing instruments. For more information please visit www.labthink.com.