This standard specifies the determination of moisture permeability of lightweight rigid packaging containers. This standard applies to the determination of moisture permeability of rigid packaging containers after single or multiple transport packaging tests. GB/T 6981-2003 Moisture permeability test method for rigid packaging containers GB/T6981-2003 Standard download decompression password: www.bzxz.net
This standard specifies the determination of moisture permeability of lightweight rigid packaging containers. This standard applies to the determination of moisture permeability of rigid packaging containers after single or multiple transport packaging tests.

GB/T6981--2003
This standard is a revision of GB/T6981--1986 "Test Method for Temperature Transmission of Rigid Packaging Containers". Compared with GB/T6981--1986, the technical content has been changed as follows:
The format of the standard text has been modified according to the requirements of GB/T1.1--2000 version; the section "Arbitration Test" has been added;
- The chapters containing the contents of "Test Conditions" and "Test Procedures" have been adjusted. This standard replaces GB/T6981--1986 from the date of implementation. This standard is proposed by the China Machinery Industry Federation. This standard is under the jurisdiction of the Mechanical Science Research Institute. The main drafting units of this standard are: Mechanical Science Research Institute, Guangzhou Electric Science Research Institute of SINOMACH, National Import and Export Product Packaging Inspection Center, Yuhua Wood Industry Co., Ltd., Jian'ou City, Fujian Province, and Changzhou Sinochem Qinfeng Plastic Co., Ltd. The main drafters of this standard are: Li Xuelong, Peng Jian, Liu Jinfeng, Zeng Yuqiang, and Gu Taosong. The previous versions of the standards replaced by this standard are as follows: GB/T 6981—1986
1 Scope
Test method for moisture permeability of rigid packaging containers
This standard specifies the determination of moisture permeability of lightweight rigid packaging containers. This standard applies to the determination of moisture permeability of rigid packaging containers after single or multiple transport packaging tests. 2 Normative references
GB/T 6981--2003
The clauses in the following documents become the clauses of this standard through reference in this standard. For dated references, all subsequent amendments (excluding errata) or revisions are not applicable to this standard. However, the parties to an agreement based on this standard are encouraged to study whether the latest versions of these documents can be used. For undated references, the latest versions shall apply to this standard. GB/T4122.1 Basic packaging terms
3 Terms and definitions
The terms and definitions established in GB/T4122.1 and the following terms and definitions apply to this standard. 3.1
Water vapor transmission of rigid containers Under the specified hot and humid test atmospheric conditions and time, test the amount of water vapor that invades the rigid packaging container whose internal air remains dry. The unit is g/m2·d.
Hot hamiding test at moshere condition The relative humidity is kept at 88% to 92%, and the temperature is kept at a constant hot and humid test air condition of 40℃±1℃. 4 Test purpose
4.1 Evaluate or screen the advantages and disadvantages of the materials, structures and process measures used in packaging containers. 4.2 Compare the moisture-proof performance of different types of packaging containers. 4.3 Determine the suitability of moisture-proof measures for rigid packaging containers dedicated to special types of products. 4.4 Indicators and control methods used to determine the moisture-proof performance requirements of packaging containers. 5 Test equipment
5.1 Test chamber (room)
5.1.1 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).
5.1.2 The relative humidity and temperature conditions of the air in the working space of the test chamber (room) shall be maintained within the specified conditions and shall be continuously circulated around the test specimen. At the same time, condensation shall not appear on the sample during the test. 5.1.3 The condensed water in the test chamber (room) shall be continuously discharged, and the discharged condensed water shall not be used as a moisture source before being purified.
5.1.4 The temperature and humidity in the working space of the test chamber (room) shall be uniform and consistent with the values ​​of the control points as much as possible. 5.1.5 The condensed water on the top and walls of the test chamber (room) shall not drip onto the specimen. 5.2 Weighing balance
The sensitivity of the balance can be within 1g or more than one-tenth of the dry weight of the product, whichever has the higher sensitivity. GB/T 6981-2003
5.3 Desiccant container or weighing bottle
Weighing bottles should be 20mm to 40mm deep, non-hygroscopic containers with sealed lids, so that the desiccant can be placed in them and then placed in the packaging container for testing.
Desiccant containers can also be used as weighing containers. Lightweight plastic containers or glass containers with lids can be used. 6 Test specimens
6.1 The test specimens should be representative and typical rigid packaging containers sealed in the same way as in actual use. 6.2 When the test specimen is used to determine its moisture permeability, the desiccant is used as the medium for absorbing water vapor. When the test purpose is to determine the suitability of the packaging container for a particular product, the product (dried) can be used instead of the desiccant, and the test container should be filled to the actual capacity.
6.3 Desiccant placement
Sufficient desiccant should be placed in the sample to keep the inside of the container dry. 6.4 Requirements for desiccant
It should have a strong affinity for water and high drying efficiency, and still have a low water vapor pressure after absorbing a large amount of water. Suitable desiccant include fine-pored silica gel and anhydrous calcium chloride. The desiccant should be granular or in small lumps. When using, the powder with a particle diameter of less than 600μm (No. 30 sieve) should be sieved out and not used.
6.5 Treatment conditions of desiccant
The drying time of fine-pored silica gel at 150℃ is not less than 5h; the drying time of anhydrous calcium chloride at 200℃ is not less than 24h. The thickness of the desiccant during drying should not exceed 25mm. 6.6 For each test, the number of samples of the same type and size shall not be less than 2. 7 Test conditions
7.1 Conventional test: temperature 40℃±1℃, relative humidity 90%±2%. 7.2 Arbitration test: temperature 40℃±0.5℃, relative humidity 90%±1%. 7.3 Unless otherwise specified in the contract.
8 Test procedure
8.1 Test procedure for resealable rigid packaging containers 8.1.1 Place an appropriate amount of desiccant in one or more containers (or weighing bottles) and place them in the center of the sample. If necessary, non-hygroscopic supports can be used to support them.
8.1.2 The desiccant can be placed in a metal mesh, fiber paper or fine cloth bag; it can also be placed in other containers that do not absorb water vapor. The depth of placement should be not less than 15mm and not more than 25mm. When placing it in the sample, the container cover should be removed and the sample should be sealed. 8.1.3 The principle of using two or more desiccant containers is: a) according to the maximum weighing capacity of the weighing balance, when the amount of desiccant in a single container exceeds the maximum weighing capacity; b) the exposed area of ​​the desiccant in the sample should be no less than 10% of the maximum cross-sectional area of ​​the sample, when the exposed area of ​​the desiccant in a single container is less than it;
c) according to the amount of desiccant used, when a single container cannot accommodate it. 8.1.4 Operating procedures during the test:
8.1.4.1 Place an appropriate amount of desiccant container in the sample, seal the container, place it in the test box (chamber), slowly preheat it to 40℃, and then conduct the test under the specified conditions.
8.1.4.2 For the wet heat test, immediately transfer the preheated sample to the wet heat test box (chamber) (if the original wet heat test box (chamber) is preheated: start humidification). The wet heat air conditions specified in 7.1 are continuously circulated freely around the sample, and the sample is continuously tested. 8.1.4.3 The operation procedure for taking out and weighing is: 2
GB/T6981—2003
a) When using a weighing container (or weighing bottle) to hold desiccant for testing, take out the sample from the test box (chamber), open the sample (packaging container), cover the weighing container, and take out the weighing container. Then seal the packaging container to prevent external moisture from invading. Weigh the weighing container containing desiccant, open the sample, put the weighing container back into the test sample, remove the cover of the container, reseal the sample, and quickly put it back into the test box (chamber) to continue the test and re-weigh regularly. b) When using a gold exhibition net, fiber paper or fine cloth bag to hold desiccant for testing, take out the sample from the test box, open the sample, take out the net bag containing desiccant, put it into the weighing container, cover it, and seal the packaging container. Weigh the weighing container containing desiccant. Open the sample, take out the desiccant net bag from the weighing container and put it back into the sample, reseal the sample, and quickly put it back into the test box (room) to continue the test and repeat the weighing periodically. 8.1.5 Take out the weighing container regularly at appropriate intervals for weighing. Record the change of increment over time and make a relationship diagram. The test time must continue until three consecutive test points form a straight line. The slope of this part of the curve is the moisture permeability value of the packaging container during the stable increment rate. 8.1.6 The accuracy of the test will be affected by weighing too frequently. The standards of various containers should determine the appropriate weighing interval according to the moisture permeability of the container. The following intervals are recommended: for packaging containers with high moisture permeability, the recommended minimum weighing interval is 2d-3d, and for packaging containers with low moisture permeability, 15d-30d weighing is recommended.
8.1.7 The sample is allowed to stay at the weighing place for 1h to allow the temperature to be properly balanced: the time taken out of the test box (room) shall not exceed 3h each time. bzxz.net
8.1.8 If the actual product is used to replace the dry explosive agent for testing, a constant incremental rate may not be obtained. When testing it, the initial weight of the water-containing or dry product should be measured before the test begins, and then the sealed sample should be placed in the wet heat test box (room) for a predetermined time (usually 30d). Then take it out and measure the average moisture content or weight of the product at the end of the test. From the two moisture contents or weights measured before and after the test, the permeability value during the period can be obtained. 8.2 Test Procedure for Non-Resealable Rigid Containers 8.2.1 When a container is filled with a special product to assess its moisture resistance, the moisture permeability of the container shall be determined in accordance with the method of 8.1.8.
8.2.2 For non-resealable containers that use desiccant and are accurately weighed in accordance with 8.1.5, an opening shall be cut on one side or top of the container to be tested to allow the desiccant container to be placed and removed. During the test, the desiccant container (or weighing bottle) shall be placed in the sample in accordance with the methods of 8.1.1 to 8.1.3, and the opening shall be designed to be re-openable and re-closable.
8.2.2.1 The method of artificially sealing the opening is to place a piece of impermeable metal sheet or plastic sheet of the same shape and larger size as the opening flat around the opening, seal it with paraffin or wadding, and ensure that it is well sealed during the entire test period. 8.2.2.2 The paraffin used for sealing can be high-temperature medical paraffin. The mud can be ordinary rubber mud, such as butyl rubber mud. 8.2.3 The operating procedure during the test is: put the desiccant container into the sample and seal the container according to the method of 8.2.2.1. Put it into the test box (chamber) and slowly preheat it to 40℃, then carry out the damp heat test, and weigh the sample reasonably at appropriate time intervals (see 8.1.6).
8.2.3.1 Preheating treatment and damp heat test shall be carried out according to 8.1.4.1 and 8.1.4.2. 8.2.3.2 When weighing, first take out the sample, open the hole cover, and cover the desiccant container (or weighing bottle) cover. Then take it out, temporarily seal the opening, and weigh the container. Open the sample opening, put the container in, take out the container cover, seal the sample, and put it into the test box (chamber) to continue the test. Repeat the weighing at appropriate intervals, and continue the test until the constant incremental rate is established as in 8.1.5. Note: During the test, if the desiccant in the weighing container (or weighing bottle) is obviously damp, the desiccant can be replaced and the test can be continued. However, the weight of the replaced desiccant should be accurately weighed before the test. 9 Test report
The test report shall include the following contents: a) Description of the moisture barrier layer materials, structure, liner and sealing process of the rigid packaging container in accordance with GB/T6981-2003; b) Description of the test method adopted;
The type and quantity of the desiccant used, or the description of the conditions when the product is used, including its moisture content before testing and the determination method; d) The number of specimens;
When the temperature and humidity conditions in the test box (room) do not meet the requirements of this test condition, the maximum range of change and the elapsed time; e)
The weighing interval;
The moisture permeability value should be calculated during the constant incremental rate, accurate to 0.01, and the average value, maximum value and minimum value should be calculated. If g)
is a product used to replace the desiccant, the moisture 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) A description of any other tests the sample has undergone before testing in accordance with this standard; i) When testing in accordance with this standard, a description of the influencing effects such as changes in the appearance of the sample during and after the test.
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