Water vapor permeability film medical dressing moisture permeability test method

Abstract : The pervious vapor adhesive film medical fixed dressing is a commonly used medical material in clinic. It needs to have good moisture permeability, and its moisture permeability rate should be greater than the skin's moisture evaporation rate. This article mainly introduces the testing method and significance of moisture permeability of adhesive medical dressings.

Keywords: medical dressing; moisture permeability; water vapor transmission rate tester; W3/031 ; Jinan Languang

First, test significance

Medical dressings are used to cover sores, wounds or other damaged skin wounds and are medical materials for wounds. At present, the materials commonly used in medical dressings include natural materials, synthetics, drug dressings, and fixing dressings. Adhesive medical fixed dressings are one type of fixed dressings.

The adhesive materials generally used for fixing include adhesive bandages and gauze, adhesive bandages and gauze, acrylic tape, and zinc oxide rubber cloth. Adhesive bandages and gauze are coated with a layer of adhesive ( rubber, polyacrylic acid ) on fabrics, nonwovens or plastic films to achieve bonding. Adhesive bandages are coated with a fine-grained dispersion of natural rubber latex on an elastic bandage. When used, it binds together but does not stick to the skin or clothing. According to the use, adhesive medical dressings can be classified into vapor-permeable film dressings and water-blocking dressings.

The water content of normal human skin within 24 h is 240 ~ 1800 g/m2 (37 °C ) . For water vapour film dressings, if the moisture permeability of the dressing is lower than the skin's moisture evaporation rate, moisture may be between the skin and the dressing. accumulation. Dip the skin severely, affecting the healing effect between the wound and the skin.

Second, test methods and equipment

YY/T 0148-2006 " General requirements for medical tapes " stipulates various types of medical tapes (also called adhesive bandages) that come in contact with the body surface or wound surface, including general requirements for adhesive dressings. The standard stipulates that if the adhesive tape shows clear water vapor ( such as water-vapor-permeable film dressing ) , the water vapor permeation per 24 h should be not less than 500 g/m2·24h , and the test of water vapor permeability is given in Appendix C. method. The method uses the principle of weighing, however, the manually-weighed measurement process reduces the accuracy and accuracy of the test.

The W3/031 water vapor transmission rate tester of Jinan Languang Electromechanical Technology Co., Ltd. is a professional water vapor transmission rate ( WVTR ) tester for thin film samples based on the weighing method test principle. Each moisture permeable cup can be independently tested. Labthink's newly designed patented mechanical structure is used to strictly ensure the accuracy of the evaporating cup weighing process. The standard purge wind speed ensures that the humidity inside and outside the permeable glass cup has a constant humidity difference. Not only strictly meet the standard requirements, but also fully automated control, improving the accuracy of the test results.

Figure 1 W3/031 Water Vapor Transmission Tester

Third, the test principle

At a certain temperature, a specific humidity difference is formed on both sides of the sample. Water vapor passes through the sample in the moisture permeable cup and enters the dry side. The change in the weight of the permeable cup over time is determined and the test is determined. Such as water vapor transmission rate and other parameters.

Fourth, the test process

Laboratory environment: Test center ambient temperature: 23.0 °C , humidity: 50% RH .

1. Cut the specimen into a circular specimen with a diameter of 74mm .

Sample 2 Sample rear surface 3 a front view of FIG.

2. Carefully remove the protective layer on the back of the sample and place the sample on the high moisture side into the moisture permeable cup.

Figure 4 Damp cup with sample

3. Make three specimens and put the specimens into the test instrument one after another. Set the test conditions to temperature 38.0 °C , humidity: 90% RH , and start the test.

4 , the instrument automatically intermittent weighing, and calculate the results. After the test is over, the results are displayed on the test software. The test results are as follows:

Sample No

Water vapor transmission ( g/m2·24h )

1

2801.7166

2

2925.7280

3

2895.8254

Summary:

The Labthink Blue Light W3/031 Water Vapor Transmission Tester can accurately measure the water vapor transmission rate of the vapor-permeable film dressing, and better reflect the moisture permeability of the product. Vapor-permeable vapor-attachment film dressings are just a typical example of medical dressings, and other moisture permeability tests such as adhesive bandages and gauze, adhesive bandages and gauze, acrylic tape, and zinc oxide blankets can all follow this test method. Labthink has been committed to providing professional testing services and equipment for customers worldwide. Over the years, it has provided tens of thousands of moisture permeability testing services to customers around the world, providing customers with reliable data support. For more information about related instruments, you can visit the website of Jinan Languang Company to check specific information or call for advice. Labthink expects to enhance the technical exchanges and cooperation with enterprises and institutions in the industry.

Copyright Notice: This article is copyrighted by Jinan Languang Electromechanical Technology Co., Ltd.

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