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Test scheme for the barrier property of BOPP cigarette envelope to external water vapor

Sep 25,2021

Source: Link Testing Instruments Co.,Ltd.

Cigarettes are made into a cylindrical shape by cutting tobacco into a paper roll. It needs to be packaged or stored in a dry environment to prevent the cigarettes from being damp and moldy. Therefore, the soft plastic cigarette wrapper used on the outside of the cigarette box is mostly biaxially stretched polymer. Propylene film (BOPP), this type of material has the advantages of high transparency and gloss, good shrinkage and certain moisture resistance and fragrance retention.

If the moisture resistance of the BOPP cigarette envelope is poor, that is, the water vapor transmission rate is too high, the cigarette is prone to damp and moldy in a high-humidity environment, which not only increases the risk of deterioration of the quality and taste of the cigarette, but also shortens the shelf life of the cigarette . Therefore, cigarette manufacturers should strictly control the barrier properties of BOPP film materials to water vapor.

LTWPT-304 water vapor transmission rate tester

The domestic water vapor barrier test methods for composite film and sheet packaging include weighing method (cup method), electrolysis method, infrared method and humidity method. The reference method standards are GB/T 1037 "Plastic Film and Sheet" Water vapor permeability test method Cup method", GB/T 21529 "Plastic film and sheet water vapor transmission rate determination electrolytic sensor method", GB/T 26253 "Plastic film and sheet water vapor transmission rate determination infrared detector Method", GB/T 30412 "Plastic Film and Sheet Water Vapor Transmission Rate Determination of Humidity Sensor Method", the reference standard in this article is GB/T 1037 "Plastic Film and Sheet Water Vapor Permeability Test Method Cup Method".

   The instrument used in this test is the LTWPT-304 water vapor transmission rate tester independently developed and designed by Link Testing Instruments Co.,Ltd.

Test principle: LTWPT-304 adopts the test principle of the vapor-permeable cup weighing method. At a certain temperature, a specific humidity difference is formed on both sides of the sample, and water vapor enters the dry side through the sample in the vapor-permeable cup , Determine the water vapor transmission rate of the sample and other parameters by measuring the change in the weight of the moisture-permeable cup over time.

Test sample and test process

Test sample: BOPP cigarette envelope used by a certain tobacco brand.

Experimental procedure:

(1) Use a sampler to cut out 3 samples with a diameter of 74mm for testing.

(2) Mount the sample on the moisture-permeable cup and close the glass sealing cover.

(3) Set parameters such as sample name, sample thickness, test temperature, and test humidity.

(4) Start the gas source and click the "Start Test" option.

(5) After the test, the instrument automatically calculates and displays the test result.

Test results and analysis

   The water vapor transmission rates of the samples to be tested are 2.4715 g/(m2·24h), 2.6243g/(m2·24h), 2.1478 g/(m2·24h).

LTWPT-304 Water Vapor Transmission Rate Test System is a professional instrument for testing the water vapor transmission rate of packaging materials such as films and sheets. The equipment is easy to operate, has high test accuracy and good repeatability, and can accurately reflect BOPP cigarette packs. The moisture barrier of the film.

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