Some standard content:
1 Scope of application
National Standard of the People's Republic of China
Test methods for water apor
transmission of rigid containers1.1 This standard is applicable to the determination of water permeability of lightweight rigid packaging containers (hereinafter referred to as containers). UDC 621.642bzxZ.net
GB6981—86
1.2 This standard can be applied to the determination of water permeability of rigid packaging containers after packaging items are packed in rigid containers, or after one or more performance tests such as drum test, vibration test, drop test, impact test and actual transportation test. 1.3 This standard is not applicable to the measurement of water permeability of rigid packaging containers made of water-absorbing materials. 1.4 For small packaging containers that require more precise weighing, the moisture permeability can be measured according to GB6982-96 "Test method for moisture permeability of flexible packaging containers".
2 Test purpose
The test of this standard is as follows: to evaluate the quality of materials, structures and processes used in the screening of packaging containers; a.
Compare the moisture resistance of different types of packaging containers; b.
Determine the suitability of moisture-proof measures for special hard packaging containers for special types of products; d. An indicator used to determine the moisture-proof performance requirements of packaging containers and to control performance based on them. 3 Terminology
8.1 Permeability of rigid packaging containers refers to the amount of water vapor in a packaging container that is sealed with a desiccant to maintain a dry state and that penetrates into the internal air to maintain a dry state within a certain period of time (usually 30 days) under the specified humidity and heat test conditions. When the moisture permeability is expressed as the surface area per square meter of the container, it is clearer and more convenient than expressing it with a single volume. In the test report, the moisture permeability is allowed to be replaced by the moisture permeability value when the surface area is 12 and the time is 30 days. The unit is: 30d. 3.2 Atmospheric conditions for humidity and heat test refers to the relative humidity maintained at 88% to 92°C, and the temperature maintained at (40°C + 1 ℃ constant humid heat test air conditions.
4 Test equipment
4.1 Test chamber
4.1.1 The test chamber (room) shall be equipped with temperature and humidity sensors and measuring devices to control and observe the temperature and humidity conditions in the chamber (room).
4.1.2 The relative humidity and temperature conditions of the air in the working space of the test chamber (room) shall be able to be maintained at the conditions specified in Article 3.2 and circulate continuously around the test samples. At the same time, condensation should not appear on the samples during the test. 4.1.3 The condensed water in the test chamber (room) shall be continuously discharged, and the discharged condensed water shall be purified by pure Before chemical treatment, water shall not be used as a moisture source.
4.1.4 The temperature and humidity of the working space of the test box (room) shall be kept uniform and as consistent as possible with the number of control points. 4.1.5 Condensed water on the top and walls of the test box (room) shall not drip onto the test specimens. 4.2 Weighing day and a half
National Bureau of Standards 1
GB6981—86
Day sensitivity can be within 1g or more than 0.1% dry weight, whichever has the higher sensitivity. 4.9 Desiccant dispenser or weighing bottle
The weighing bottle should be a non-hygroscopic container with a sealed lid and a depth of 20 to 40mm, such as Φ 50×30 flat weighing bottle, etc., so that the desiccant can be placed in it, and then placed in the packaging container for testing. The desiccant container can also be used as a weighing container. Lightweight plastic containers or glass containers with lids, such as plastic cups, can be used as desiccant containers.
5 Test samples
5.1 The test sample should be representative and a typical hard packaging container sealed in the same way as in actual use. 5.2 When the test sample is used to determine, study, develop, control or certify its moisture permeability, the desiccant is used as a medium to absorb water vapor. When the test is to determine the suitability of a special product packaging container, the product (desiccated) can be used instead of the desiccant. In this case, the test container should be filled to the actual use. 5.3 The amount of desiccant placed under the test sample should be enough to keep the inside of the container dry. The amount can exceed 100g. When the container cannot hold 100g, it should be filled to at least half of its volume. Note: Desiccant should have strong affinity for water and high drying efficiency, and have low water vapor after absorbing a large amount of water. Suitable desiccant include fine-porous silica and hydrous calcium chloride. Desiccant should be in the form of granules or small balls. When using, remove the powder with small particle size (No. 30 sieve) and do not use it.
1 Desiccant should be treated with olefin before use. The treatment conditions are that the porous sample is dried at 15℃ for not less than 5h, and the anhydrous calcium chloride is dried at 200℃ for not less than 24h. During drying, the height of the desiccant should not exceed 25mm. 5.4 In each test, the number of test samples of the same type and size shall not be less than 2. 6 Test method
According to the structure of the packaging container, the test method is divided into two types: method A uses a resealable packaging container, and method B uses a non-resealable packaging container. 6.1 Test steps of method A
6.1.1 Place the selected amount of desiccant in one or more containers (or weighing bottles) and place them in the center of the test sample. If necessary, use non-hygroscopic supports to support them. 6.1.2 The desiccant can be placed in a metal mesh, fiber paper or fine cloth bag, or in other containers that do not absorb water vapor. The depth of placement should be no less than 15mm and no more than 26mm. When placed in the test sample, the cover of the container should be removed and the test sample should be sealed. 6.1.3 The principle of using two or more desiccant containers is: a. The maximum weighing capacity of the weighing balance is the same as that of the weighing balance. b. The exposed area of the desiccant in the test sample is no less than 10% of the maximum cross-sectional area of the test sample. c. According to the amount of desiccant used, when a single container cannot accommodate it. For the test of desiccant in colored bottles, if it is found that the desiccant is obviously damp during the test, the desiccant can be replaced and the test can be continued. The replaced desiccant should be accurately weighed before the test. 6.1.4 Place the test sample in the test box and test according to the conditions specified in 4.1.2. 6.1.5 Take out the weighing container regularly at appropriate intervals for weighing. Record the change of increment time and make a relationship diagram. The test must be continued until at least three consecutive test points are obtained. The slope of the straight line of this part of the curve is the moisture permeability value of the packaging container during the specified increment rate. 6.1.6 The operating procedures during the test are as follows:
6.1.6.1 Place the selected amount of desiccant in the container and immediately put it into the sample. Seal the container and put it in the test box (chamber) to slowly heat it to 40℃: then produce
GB 6981B6
6.1.6.2 Humidity test: immediately transfer the preheated test sample into the humidity test chamber (air) (or if it was originally preheated in the humidity test chamber (room), humidify it and circulate it freely around the test sample under the humidity and heat conditions specified in Article 3.2 of this standard to continuously test the test sample.
6.1.6.3 The operating procedure for taking out and weighing is: When using a weighing device (or weighing plate) to load the desiccant, take out the desiccant from the weighing device (or weighing plate). Take out the test sample from the test box (chamber), open the test sample (packaging container), cover the weighing container, and then seal the packaging container to prevent external moisture from invading. Weigh the weighing container containing desiccant, open the test sample, put the weighing device back into the test sample, remove the weighing device cover, reseal the test sample, and quickly put it back into the test box (chamber) to continue the test and recalculate the weighing regularly. b. When using metal mesh, fiber paper or fine cloth bag to pack desiccant for testing , is to take out the test sample from the test box, open the test sample, take out the net bag containing the desiccant, put it into the weighing device, and cover it. Weigh the weighing device containing the desiccant. Open the test sample. Take out the desiccant net bag from the weighing device and put the test sample in it, reseal the test sample, and quickly put it back into the test box (room) to continue the test. Repeat the weighing regularly. 6.1.7 The accuracy of the test will be affected by too frequent weighing. Relevant professional standards should be based on According to the moisture permeability of the container, the appropriate weighing interval is determined by the user. The following intervals are recommended: For packaging containers with commercial moisture permeability, the recommended minimum weighing interval is 2 to 3 days. For packaging containers with low moisture permeability, weighing is recommended every 15 to 30 days.
6.1.B The test sample is allowed to stay at the weighing place for 1 hour to make the temperature appropriate. Take the test sample outside the test box (room) for no more than 3 hours each time.
6.1.9 If the actual product is used to replace the desiccant for testing, a constant rate of increase may not be obtained. When testing it, the initial moisture content or the weight of the desiccant product should be measured before the test begins, and then the sealed test sample should be placed in a damp heat test chamber (room) for a predetermined test time (usually 30 days). Then take it out and measure the average moisture content or weight of the product at the end of the test. The moisture permeability value during the period can be obtained from the two moisture contents or weights measured before and after the test. 6.2 Test steps of method B
6.2.1 When the packaging container is filled with special * When using a desiccant to assess the moisture resistance of a container, the moisture permeability of the packaging container shall be determined according to the method of 6.1.9.
6.2.2 For non-re-sealable packaging containers that use a desiccant and are accurately weighed according to 6.1.5, a hole that can be cut on the side or top of the packaging container to be tested to allow the desiccant to be easily removed shall be cut. During the test, the container (or weighing bottle) containing the desiccant shall be placed in the test sample according to the methods of 6.1.1 to 6.1.3, and the hole shall be made so that it can be repeatedly opened and re-closed. .
6.2.2.1 The method of artificially sealing the hole is: use a non-wettable metal sheet of the same shape as the hole but larger than the hole to stick around the hole, and use wax or sealing mud to seal it, and ensure that it is well sealed during the entire test period. 6.2.2.2 The wax before sealing can be high-temperature medical wax. The sealing mud can be ordinary rubber sealing mud, such as base rubber sealing. 6.2.3 The operating procedure during the test is: put the selected amount of desiccant into the storage device and immediately put it into the test sample, and seal the container according to the method in 6.2.2.1. Place it in the test box (chamber) and slowly preheat it to 40℃, then carry out the wet heat test, and weigh the test sample at appropriate time intervals (see 61.7). 6.2.3.1 Preheating wet heat test shall be carried out in accordance with 6.1.6.1 and 6.1.6.2. 6.2.3.2 When weighing, take out the test sample first:, open the hole cover, cover the desiccant container (or weighing bottle) cover, and take out, temporarily close the hole, and weigh the busy device. Open the test sample hole, put the container in, take out the delay cover, seal the test sample, and place it in the test box (chamber) to continue the test. Repeat the standard measurement at appropriate intervals, and the test continues until the constant incremental rate established in 6.1.5 is reached: a
Note: During the test, if it is found that the desiccant in the weighing container (or weighing bottle) is obviously damp, the lower desiccant can be replaced and the test can be continued. However, the replaced desiccant should be accurately weighed before testing. 7. Test report
The test report should include the following contents: a.
GB 6981-86
Description of the moisture barrier layer materials, structure, liner and sealing process of the hard packaging container; b.
Description of the test method adopted;
The type and quantity of desiccant used, or the description of the situation when the product is used, including the method for determining the moisture content before testing; d.
The number of test samples;
When the temperature and humidity conditions in the test box (room) do not meet the requirements of Article 2.3 of this standard, the maximum range of change and the time experienced; e.
Description of the time,
f. The weighing interval,
name. The moisture permeability value should be calculated to the value during the constant growth rate, and the significant digits should be taken to calculate the average value, maximum and minimum value. If the product is used to replace the desiccant, the water content and net weight of the contents before and after the test should be given, from which the 30-day moisture permeability value can be calculated: h. Description of the test results of any other tests that the test sample has been subjected to before the test according to this standard: i. When testing according to this standard, the appearance changes of the test sample during and after the test and other influencing effects. Additional explanation:
This standard was proposed by the Ministry of Machinery Industry of the People's Republic of China. This standard was established by the Standardization Research Institute of the Ministry of Machinery Industry. This standard was drafted by the Guangzhou Electric Science Research Institute of the Ministry of Machinery Industry. The drafters of this standard were Xu Guobao, Ren Zhihu, Chen Guansheng, and Zeng Qinglu.
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