Moisture-proof packaging is widely used in machinery, electronics, food, pharmaceuticals, and daily chemicals, and is one of the most common forms of protection for products during circulation from water vapor. Moisture-proof packaging plays a crucial role in preventing the contents from rusting and deteriorating. GB/T 5048-1999, the standard for moisture-proof packaging, clearly stipulates the grades and testing methods for moisture-proof packaging. Labthink (www.labthink.cn), as a leading provider of testing instruments and inspection services, will now introduce the requirements for testing methods in conjunction with relevant testing instruments. [b]I. Standards for Moisture-proof Packaging[/b] [b]II. Requirements for the Moisture-proof Performance and Sealing/Sealing Performance of Packaging Materials in Moisture-proof Packaging[/b] 1. Requirements for the Moisture-proof Performance (Moisture Barrier) of Moisture-proof Packaging Materials: The moisture permeability of moisture-proof packaging materials or containers should be selected according to the grade of the moisture-proof packaging as shown in the table below. The water vapor permeability of moisture-proof packaging materials should comply with GB/T 1037 (Water Vapor Permeability Cup Method for Plastic Films and Sheets). The moisture permeability of rigid moisture-proof packaging containers should comply with the relevant provisions of GB/T 6981 (Test Method for Moisture Permeability of Rigid Packaging Containers), and the moisture permeability of flexible packaging containers should comply with the relevant provisions of GB/T 6982 (Test Method for Moisture Permeability of Flexible Packaging Containers). 2. Requirements for the sealing heat seal strength of moisture-proof packaging materials: The sealing heat seal strength of moisture-proof packaging should be tested according to the provisions of GJB145 A-1993 (Specification for Protective Packaging), and should be greater than 30 N/5 cm. 3. Requirements for the sealing performance of moisture-proof packaging: The sealing performance of moisture-proof packaging should be tested according to the provisions of GB/T 15171 (Test Method for Sealing Performance of Flexible Packaging), and the packaging should be free from defects such as pinholes, tears, and open seals. III. Moisture-proof Packaging Tests and Methods 1. Moisture-proof Packaging and Material Water Vapor Permeability Testing According to standards, the testing of moisture-proof packaging materials requires the use of the cup method, which is essentially another name for the gravimetric method for testing water vapor permeability. The principle is to use a weighing method to determine the moisture permeability and other parameters of the sample by measuring the weight change of the permeable cup per unit time. Here, we will use Labthink's TSY-T series instruments as an example. This series has four instruments, all using the gravimetric method. Traditional testing methods involve manual weighing using a permeable cup, a constant temperature and humidity chamber, and a balance. However, because the water vapor permeability of moisture-proof packaging is relatively small, this method involves many manual interventions, significantly impacting the test results and resulting in long testing times and low accuracy. Labthink's TSY-T series moisture permeability tester not only meets the standard testing requirements but also features a world-first fully automated testing method. Simply clamp the prepared sample into the permeable cup, start the test, and the instrument will automatically run, monitor the test progress, end the test, and automatically generate a test report. The testing process is intelligent and requires no human intervention, resulting in accurate and reliable test data. Furthermore, based on practical applications, packaging materials undergo multiple production processes such as molding, filling, and heat sealing, often leading to uneven thickness and poor sealing. This necessitates testing not only the packaging material itself but also the entire moisture-proof packaging system. Labthink's PERME W3/330 water vapor transmission rate testing system perfectly meets the need for dual testing. Additionally, this instrument uses a main unit/satellite unit mode, with one main unit supporting up to nine satellite units, enabling simultaneous testing of 30 different materials. 2. Test of the heat seal strength of moisture-proof packaging materials: The heat seal strength of moisture-proof packaging should be tested according to GJB145 A-1993 (Protective Packaging Specification), and should be greater than 30 N/5 cm. In practice, the existing standard for testing heat seal strength is QB/T 2358 (Test Method for Heat Seal Strength of Plastic Film Packaging Bags), which can be followed. To perform the testing methods specified in the standard, two devices are required: a heat-sealing tester and a tensile testing machine. The heat-sealing tester simulates the temperature, time, and pressure parameters of the sealing process on the production line to heat-seal the sample. Labthink's HST-H3 heat-sealing tester is the testing instrument for sample preparation in the laboratory sealing heat-sealing strength testing stage. The tensile testing machine applies tensile force to the sealed part to separate it, thereby testing the sealing heat-sealing strength. Labthink's XLW series intelligent electronic tensile testing machine is specifically designed for testing the sealing heat-sealing strength of moisture-proof packaging materials. Simply select the "heat-sealing strength" test function to complete the test automatically. In addition, this instrument also has functions for testing the tensile strength and elongation of moisture-proof packaging, the interlayer peel strength of composite films, tear strength, and puncture performance. 3. Sealing performance testing of moisture-proof packaging The sealing performance testing of moisture-proof packaging needs to be carried out in accordance with the provisions of GB/T 15171 (Test method for sealing performance of flexible packaging). Taking Labthink's MFY-01 sealing tester as an example, this instrument consists of a main unit, a vacuum generator, and a vacuum chamber. The test examines packaging for defects such as pinholes, tears, and open seals. First, the packaging is placed in a vacuum chamber filled with water. The vacuum holding time is set between 30 and 60 seconds, with the vacuum level set to one of the following values: 20, 30, 50, or 90 kPa. The test is started, the vacuum level is reached, and maintained for the set time. Leakage of the sample is observed during vacuuming and the vacuum holding period, noting the presence or absence of continuous bubbles. A single isolated bubble is not considered a leak. This is a brief introduction to moisture-proof packaging standards, testing methods, and instruments. Labthink hopes to engage in comprehensive exchanges with industry colleagues on more quality control and testing items and methods. Editor: He Shiping