Abstract: The moisture permeability of medical dressings has an important impact on the cleaning and healing of wounds, and is an important aspect to measure its performance. In this paper, Labthink W3 / 031 water vapor transmission rate tester is testing equipment, the water vapor transmission rate test samples foamed medical dressings by multimeric inverted cup method, and the principle of the device, parameters and scope The test process is briefly described to provide a reference for the monitoring of the moisture permeability of medical dressings. Key words: medical dressing, water vapor transmission rate, moisture permeability, water vapor transmission rate tester, weighing method, inverted cup method, cup method 1. significance Medical dressings are medical materials that can be used to cover skin damage such as sores, wounds, and the like. Most of the early medical dressings are made of natural gauze material. They have high permeability, easy adhesion to the wound, and external microorganisms easily pass through infection wounds. It is easy to make the wound dehydrated and difficult to heal, and consume natural resources. Therefore, in order to solve the above problems, natural gauze is gradually replaced by polymer materials such as polymembrane, foamed polymer, and hydrocolloid. These dressings are freely permeable to gases such as oxygen and water vapor, and particulate matter and microorganisms in the environment. The inability to pass, while having good moisturizing properties, can make the wound moist and not easily adhered, and prevent cross-infection, accelerate wound healing, and save the cost of changing dressing. Medical dressings should have high water vapor transmission properties, so that the skin has good moisture retention. The moisture permeability of the medical dressing can be verified by the inverted cup method on the water vapor barrier of the dressing and the skin contact side, which is usually measured by the water vapor transmission index. If the water vapor permeation amount is high, the moisture retention of the dressing is indicated. better. Therefore, medical dressing-related manufacturers should strengthen the monitoring of water vapor permeability of products to prevent the water vapor permeation of products from being too low, resulting in difficult wound healing. Figure 1 medical dressing and its way of covering the skin 2. Test samples A sample of a foamed multimeric medical dressing provided by a pharmaceutical company. 3. Detection basis Due to the relevant test standards for the domestic cupping test, the relevant GB 1038-1988 only gives the weight gain method based on the principle of desiccant moisture absorption, which cannot be used for the inverted cup method of direct contact of distilled water with the sample, so this test Refer to the relevant US standard ASTM E96-2015 "Material Vapor Transmission Test Method". 4 , test equipment Jinan Languang Electromechanical Technology Co., Ltd. independently developed the W3/031 water vapor transmission rate tester. Figure 2 W3/031 water vapor transmission rate tester 4.1 Test principle W3/031 adopts the principle of wetting cup weighing method. Under certain temperature, the specific humidity difference is formed on both sides of the sample. The water vapor passes through the sample in the moisture permeable cup and enters the dry side. The amount of change in the weight of the moisture permeable cup over time is determined by parameters such as the amount of water vapor permeation of the sample. 4.2 Scope of application (1) This equipment is suitable for testing the water vapor transmission rate (rate) of plastic film, sheet, paper, cardboard and textile, non-woven fabric and other packaging materials. (2) This equipment can meet a variety of national and international standards, such as ASTM E96 , YY/T 0148 , GB 1037 , GB/T 16928 , ASTM D1653 , TAPPI T464 , ISO 2528 , DIN 53122-1 , JIS Z0208 , YBB 00092003 . 4.3 Equipment parameters 5. Test process (1) Three samples of 74 mm in diameter were cut from the sample by a sampler for testing. (2) The sample is placed on three moisture permeable cups, and the moisture permeable cup is placed upside down to ensure that the distilled water in the cup is in full contact with the sample. (3) Place the three moisture permeable cups in the inner bracket of the instrument and close the glass sealing door. (4) Set the sample name, sample thickness, test temperature ( 38 °C ), test humidity ( 90% RH ) and other parameters. (5) Start the air supply and click the “ Start Test †option. (6) After the test is over, the instrument automatically calculates and displays the test results. 6. Test results The water vapor permeation amount on the inner side of the foamed polymer medical dressing sample tested in this test was: 1203.64 g/m 2 ? 24h , 1159.87 g/m 2 ? 24h , 1266.75 g/m 2 ? 24h . Refer to YY/T 0148-2006 " General requirements for medical tapes " for adhesive tape ( such as water vapor vapour film dressing ) . The water vapor permeation per 24 hours should be no less than 500 g/m 2 · 24h . Medical dressings have good water permeability. 7. Conclusion W3/031 Water Vapor Transmission Rate Tester is a professional testing equipment for water vapor barrier monitoring. It has high test accuracy and good repeatability of test results, which can truly reflect the water resistance or water permeability of materials. Labthink has been committed to providing professional testing services and equipment to customers around the world, providing customers with a large number of packaging material performance data references. At the same time, provide customers with reliable technical solutions. Labthink is looking forward to enhancing technical exchanges and cooperation with users in various industries. YT-T11 YT-T11 Shenzhen Sunshine Technology Co.,Ltd , https://www.szyatwin.com
