This standard specifies the test instrument, sample preparation, test steps and result calculation of the water vapor transmission rate test method for pressure-sensitive adhesive tapes. This standard is applicable to the determination of water vapor transmission rate of pressure-sensitive adhesive tapes with a width of not less than 50 mm. GB/T 15331-1994 Test method for water vapor transmission rate of pressure-sensitive adhesive tapes GB/T15331-1994 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Test method for water vapor transmission of pressure-sensitive tapes
Subject content and scope of application
GB/T15331-94
This standard specifies the test instrument, sample preparation, test steps and result calculation of the test method for water vapor transmission of pressure-sensitive tapes. This standard is applicable to the determination of water vapor transmission rate of pressure-sensitive tapes with a width of not less than 50mm. 2 TerminologybZxz.net
Water vapor transmission rate (WVTR) - the ability of a unit area of ​​an adhesive tape to transmit water vapor through itself within a specified time. 3 Principle
The pressure-sensitive adhesive tape is tightly attached to a test plate containing a desiccant to form a test piece, which is exposed to a controlled environment and the mass of the test piece after two different time intervals is weighed. The water vapor transmission rate is calculated based on the increase in its mass. 4 Instruments and equipment
4.1 The test plate is made of a non-hygroscopic material and has a water vapor transmission rate of zero. The pan shall have a flat, smooth, rigid flange and dimensions as shown below:
150 ± 03.5
100 ± 0.5
Test pan
The mass of the test pan shall not exceed 80% of the capacity of the balance used for weighing. 25+0.5±12.
4.2 Desiccant, anhydrous calcium chloride that can pass through a sieve with a mesh diameter of 2.80 mm, can be dehydrated and activated by heating at 200°C for 2 h.
4.3 Test chamber, capable of maintaining a temperature of 38 ± 1°C and a relative humidity of 90% to 95%. Air shall be circulated in the chamber to ensure uniform conditions for all specimens. There shall be no noticeable condensation of vapor on the test pan. 4.4 Balance, with a graduation of 1 mg.
Approved by the State Administration of Technical Supervision on December 22, 1994 and implemented on October 1, 1995
5 Sample preparation
5.1 Sampling shall be carried out in accordance with product standards.
5.2 At least three specimens shall be prepared for each sample. GB/T 1533194
5.3 The specimen taken from the sample shall be at least 50 mm wide and 155 mm long. 5.4 Before selecting the test specimen, at least 3 layers, but not more than 6 layers of outer tape shall be unfolded and removed from the sample roll. 5.5 Remove the sample from the freely rotating roll at a rate of 500~750mm/s. If the roll cannot be separated at this rate due to the width of the roll or other reasons, the sample shall be removed at a rate as close to 500mm/s as possible. 6 Weighing conditions
The temperature during weighing is 23±2℃ and the relative humidity is 45%~55%. 7 Test Procedure
7.1 Prepare not less than three specimens.
7.2 Fill the test pan with anhydrous calcium chloride to a depth of approximately 3 mm from the opening, ensuring that the calcium chloride does not come into contact with the adhesive tape. 7.3 Bond the specimen to the flange with the adhesive side facing the flange. No bubbles or wrinkles are allowed. Use finger pressure to achieve this. If the specimen material is larger than the specimen size, trim the specimen material to the flange edge size. If the adhesive is missing or the bond to the flange is not strong enough to maintain a seal when exposed, or if only water vapor permeability is to be examined perpendicular to the surface of the adhesive tape backing, a sealing material such as aluminum foil pressure-sensitive adhesive tape may be used to ensure that only an area of ​​25 mm × 100 mm is exposed at the flange opening and that all edges are sealed. 7.4 Prepare the remaining specimens in the same manner as the first specimen. 7.5 Place each test piece in a test chamber at 381°C and 90% to 95% relative humidity for 24 h, remove and cool for 15 min under weighing conditions, remove visible water from the test piece with a lint-free absorbent cloth or paper, weigh to the nearest 5 mg, and use this as WI in the equation in Chapter 8.
7.5.1 For materials with an estimated WVTR value of 40 g/m2·24h or less, place the assembly back in the test chamber after initial weighing and allow to stand for 72 h. Remove and cool for 15 min under weighing conditions, remove water droplets, and weigh again to the nearest 5 mg, and use this as W in the equation in Chapter 8.
7.5.2 For materials with an estimated WVTR value greater than 40 g/m2·24h, place the test piece back in the test chamber after initial weighing and allow to stand for 48 h. Remove, cool, and weigh as specified in 7.5.1 to obtain Wz. 7.5.3 For adhesive tapes with unknown WVTR values, first measure them according to 7.5.2. If the WVTR value is greater than or equal to 40g/m2·24h, the test is over.
If the WVTR value is less than or equal to 40g/m2·24h, the adhesive tape specimen should be immediately put back into the test chamber for 48h and measured again according to 7.5.2. The W, value measured for the first time and the W, value measured for the second time are used as the test results and substituted into the formula in Chapter 8 for calculation.
8 Result calculation
8.1 Calculate the water vapor transmission rate (WVTR) of each specimen in the adhesive tape area (g/m2) according to the following formula, accurate to 0.05g/m224h.
WVTR - (W,W) · 24
WVTR-~-water vapor transmission rate, g/m2·24h388
GB/T 15331---94
W,---mass of the test piece at the time of exposure test for 24h, gWz——-mass of the test piece at the end of exposure test, g; T...Exposure test time between W, and W., h; 4--opening area of ​​the test plate, m2.
9Test report
The test report shall include the following contents:
Name of manufacturer and name and brand of adhesive tape: production date and batch number;
Edge is sealed;
Each single value and arithmetic mean of the test results; other contents to be reported.
Additional remarks:
This standard is proposed by the Ministry of Chemical Industry of the People's Republic of China. This standard is under the jurisdiction of the National Adhesive Standardization Technical Committee. This standard was drafted by the Tuhai Rubber Products Research Institute. The main drafters of this standard are Zhang Wengang, Sun Guoan, and Liu Qianling.
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