Resistance of the hottest EVOH high barrier compos

Verification of EVOH high barrier composite sheet's barrier to external water vapor

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core tip: EVOH material is more and more widely used in packaging, which is a material with high barrier performance. This paper uses Labthink w3/330 water vapor transmission test system to test the barrier performance of EVOH high barrier composite sheet against external water vapor, and briefly introduces the basic process of the test, the scope of application of the test equipment, equipment parameters and other contents, which can be used as a reference when enterprises choose the moisture permeability test equipment and test methods

[China Packaging News] EVOH material is more and more widely used in packaging, which is a material with high barrier performance. This paper uses Labthink w3/330 water vapor transmission test system to test the barrier performance of EVOH high barrier composite sheet against external water vapor, and briefly introduces the basic process of the test, the scope of application of the test equipment, equipment parameters and other contents, which can be used as a reference when enterprises choose the moisture permeability test equipment and test methods

key words: EVOH, high barrier, moisture resistance, water vapor transmission, water vapor transmission test system

1, significance

evoh material is a new barrier material, which has excellent gas resistance, transparency, gloss, mechanical strength, scalability, wear resistance, cold resistance and surface strength. At the same time, it has the highest thermal stability among high-performance barrier resins. This property can make production waste reused. In the food industry, it is used for aseptic packaging, hot filling and cooking bags, packaging dairy products, meat, canned fruit juice and condiments. However, under high humidity, EVOH's barrier performance will decline to a certain extent, so it is generally used as the intermediate layer of composite materials to prevent affecting the shelf life of products

2. Reference standard

there are weighing method (cup method), electrolysis method, infrared method and humidity method related to the water vapor test of soft composite sheet packaging in China. This paper refers to the standard gb/t "determination of water vapor transmittance of plastic film and sheet electrolytic sensor method" for testing. Other methods and standards that can be referred to are GB test method for water vapor permeability of plastic films and sheets cup method, gb/t test method for packaging materials moisture permeability, gb/t determination of water vapor transmission of plastic films and sheets infrared detector method, and gb/t determination of water vapor transmission of plastic films and sheets humidity sensor method

3. Test sample

pp/evoh/pp high barrier composite sheet produced by a factory

4. Test equipment

w3/330 water vapor transmission test system independently developed and designed by Jinan Languang Electromechanical Technology Co., Ltd

Figure 2 w3/330 water vapor transmission test system

4.1 test principle

w3/330 adopts the test principle of electrolytic sensor method. Nitrogen with stable relative humidity flows on one side of the film, and dry nitrogen flows on the other side of the film; Due to the existence of humidity gradient, water vapor will diffuse from the high humidity side through the film to the low humidity side; On the low humidity side, the transmitted water vapor is carried to the sensor by the flowing dry nitrogen. When entering the sensor, an electrical signal of the same proportion will be generated. Through the analysis and calculation of the electrical signal of the sensor, the water vapor transmittance and other parameters of the sample can be obtained. For packaging containers, dry nitrogen flows in the container, and the outside of the container is in a high humidity state

4.2 scope of application

phosphoric acid is a part of Guoneng battery. The requirements put forward iron lithium series and 3-yuan series batteries (1) this equipment is suitable for testing the water vapor transmission rate of plastic sheet, film, paper, paperboard and its composite materials, containers and other packaging

l sheet materials include water vapor transmission test of various engineering plastics, rubber, building materials and other sheet materials, such as PP sheet, PVC sheet, PVDC sheet, etc; Water vapor transmission test of paper and paperboard, such as aluminum coated paper for cigarette packs, paper aluminum plastic composite sheets, etc

l film materials include various plastic films, plastic composite films, paper plastic composite films, coextrusion films, aluminized films, aluminum foil, aluminum foil composite films, glass fiber aluminum foil paper composite films, etc

l containers include bottles, bags, cans, boxes and barrels made of plastic, rubber, paper, paper plastic composites, glass, metal and other materials, such as Coke bottles, peanut oil barrels, Tetra Pak packaging, vacuum packaging bags, metal three piece cans, plastic cosmetics hose packaging, toothpaste hose packaging, jelly cups, etc

in addition, this equipment is equipped with special devices, which can also be used to test the water vapor transmission rate of special packaging such as pharmaceutical packaging, automobile fuel tank, battery plastic shell, plastic pipe, solar backplane, etc

(2) this equipment can meet a number of national and international standards, such as gb/t 21529, ISO, DIN, YBB

4.3 equipment parameters

l test range: film test 0.001 ~ 40 g/(M2 24h), container test 0 Tensile testing machine control advantages 0001 ~ 0.2 g/pkg D

l number of samples: 1 ~ 3 pieces (data independent)

l resolution: film 0.001 g/m2 24h, container 0.00001 g/pkg D

l test temperature range: 15 ℃ ~ 55 ℃, temperature control accuracy 0.1 ℃; Test humidity range: 0% RH, 35% RH ~ 90% RH, 100% RH, temperature control accuracy 1% RH

l the system can support the parallel connection of up to 10 instruments, and establish an efficient system for the simultaneous test of 30 samples

l can be matched with the oxygen transmittance test system to form a hybrid test system, which is controlled by a computer to achieve an efficient and convenient test method for the simultaneous test of water vapor and oxygen transmittance

l support lystemtm laboratory data to be widely used, data sharing system, unified management of test results and test reports

5 During the test process

(1) cut three 108 mm samples with a sampler

(2) clamp three samples on three test chambers of the equipment

(3) set the sample name, sample thickness, test temperature, test humidity and other parameters, and click the start test option

(4) start the air source, adjust the nitrogen flow and nitrogen pressure to make the humidity and nitrogen flow of the test chamber reach the specified value

(5) after the test, the instrument automatically calculates and displays the test results

6. Test results

the water vapor transmission rates tested in this paper are 0.0107 g/(M2 24h), 0.0126 g/(M2 24h), 0.0149 g/(M2 24h) respectively

7. Conclusion

pp/evoh/pp high barrier composite sheet is used in instant foods such as Babao porridge. According to the food characteristics, it is necessary to ensure that the product has high barrier performance, but EVOH's barrier performance in high humidity environment will be reduced to a certain extent. Therefore, when selecting packaging materials, we should strengthen the test of its moisture resistance to prevent the deterioration of the taste of the product in the shelf life. W3/330 water vapor transmission testing system is a professional water vapor transmission testing instrument for film testing and container testing. The equipment has the advantages of simple operation, high testing accuracy and good repeatability. As an excellent supplier of packaging testing equipment, Labthink Languang has always been committed to providing professional and high-end packaging testing equipment and testing services for customers all over the world. You can log in to view specific information or call directly for consultation. The more you understand, the more you trust! Jinan Languang Electromechanical Technology Co., Ltd. is willing to take this opportunity to enhance technical exchanges and cooperation with enterprises and institutions in the industry