Abstract: Fiberboard is a moisture-sensitive material, and good moisture resistance is an important guarantee for extending the service life of fiberboard. This paper introduces an effective method for characterizing the moisture resistance of fiberboard through the test of water vapor transmission rate of fiberboard samples, and through the test principle, test process and equipment used W3 / 062 water vapor transmission rate test system parameters, applicable The introduction of the scope and other contents provides a reference for the monitoring of the moisture resistance of fiberboard.
Keywords: moisture resistance, water vapor transmission rate, water vapor transmission rate test system, fiberboard
1. Significance
Fibreboard is a kind of raw material made of lignocellulose or other plant cellulose, which is made of its own adhesiveness or added with adhesives. It is widely used in the construction industry and home decoration industry. During the use of fiberboard, warpage is a common problem, which affects the appearance and service life of the product. This problem has a great relationship with the moisture absorption of fiberboard. In order to reduce the moisture absorption of fiberboard, it is often found in The surface of the fiberboard is coated with waterproof material or the density of the fiberboard is increased, and the service life of the fiberboard is extended. The traditional method of testing the moisture resistance of fiberboard is to soak the sample in water for a certain period of time to detect its performance change. This method tests the resistance of fiberboard to water under extreme conditions and cannot be used to accurately evaluate the daily use of fiberboard The hygroscopicity under the ambient humidity conditions in the paper, therefore, this paper specifically introduces the concept of fiberboard water vapor transmission rate for evaluating its moisture resistance under ambient humidity.
Figure 1 Fiberboard
2. Test samples
This test uses a certain brand of fiberboard as the test sample to test its water vapor transmission rate.
3. Test basis
At present, the test methods for water vapor transmission rate of sheet materials are cup method, infrared sensor method, electrolytic sensor method and humidity sensor method. Considering the high moisture permeability of fiberboard materials, this test uses a cup with a larger test range The water vapor transmission rate of the sample is tested according to the standard method, according to the standard GB 1037-1988 "Test method for water vapor permeability of plastic films and sheets. Cup method".
4. Test equipment
This article uses the W3 / 062 water vapor transmission rate test system as the test equipment, which is independently developed and produced by Jinan Languang Electromechanical Technology Co., Ltd.
Figure 2 W3 / 062 water vapor transmission rate test system
4.1 Test principle
The cup method is based on the principle that the penetration of water vapor causes a change in the quality of the moisture-permeable cup, and further tests the water vapor transmission rate of the material. According to the increase or decrease of the quality of the moisture-permeable cup, this method is divided into two test methods: weight-increasing method and weight-reducing method. ; The weight loss method is to put a certain amount of distilled water into the moisture-permeable cup, and the outside of the moisture-permeable cup is a low-humidity environment. Either way, under the drive of the humidity difference, the water vapor will penetrate from the high humidity side to the low humidity side through the sample. The weight increase method shows that the mass of the vapor permeable cup increases, and the weight loss method shows that the mass of the vapor permeable cup decreases. When the change of the mass with time is constant, the penetration of water vapor on both sides of the sample reaches equilibrium. At this time, the water vapor transmission rate of the sample is calculated according to the change of the quality of the moisture-permeable cup during the test interval.
4.2 Device parameters
This equipment can realize two test modes of weight-increasing method and weight-reducing method. The test range of weight-increasing method is 0.1 ~ 2500 g / (m2 · 24h), the test range of weight-reducing method is 0.1 ~ 10,000 g / (m2 · 24h), Test accuracy is 0.01 g / (m2 · 24h), system resolution is 0.001g; temperature and humidity automatic control, wide range, high accuracy, temperature control range is 15 ~ 55 ℃, temperature control accuracy is ± 0.1 ℃; weight reduction method The humidity control range is 70 ~ 90% RH, the weight control method humidity control range is 10 ~ 98% RH, and the humidity control accuracy is ± 1% RH, which can achieve the test of water vapor transmission rate under different temperature and humidity conditions; purge wind speed range 0.5 ~ 2.5 m / s; sample size is Ф74 mm, test area is 33 cm2; the system automatically weighs intermittently, the system automatically clears before each weighing, the test chamber can accommodate 6 moisture-permeable cups, each The moisture-permeable cup can be independently tested, and can simultaneously test 6 kinds of the same or different samples; support LystemTM laboratory data sharing system.
4.3 Scope of application
(1) This equipment is suitable for testing the water vapor transmission rate of various types of materials, such as plastic film, paper-plastic composite film, geomembrane film, aluminized film, aluminum-plastic composite film, waterproof breathable film and other film materials, PP sheet , PVC sheet, PVDC sheet and other engineering plastics, rubber, building materials and other sheet materials, cigarette pack aluminum foil paper, Tetra Pak and other paper, cardboard materials, waterproof breathable fabric, diaper non-woven fabric, sanitary products without Textiles and other textiles, non-woven fabrics and other materials. In addition, it can also be applied to the test of moisture permeability, water resistance and moisture retention of materials and products such as artificial skin, medical supplies and accessories, solar backboard, LCD film, paint film, cosmetics, biodegradable film and other products.
(2) This equipment meets many national and international standards, such as GB 1037, GB / T 16928, ASTM E96, ASTM D1653, TAPPI T464, ISO 2528, DIN 53122-1, JIS Z0208, YBB 00092003, etc.
5. Test process
(1) According to the size of the moisture-permeable cup, cut three samples from the fiberboard sample, and seal the sample with wax on three moisture-permeable cups with a certain amount of distilled water, to ensure that the moisture-permeable cup and the sample Sealed well.
(2) Put the moisture-permeable cup of the sealed sample on the tray in the test chamber of the equipment, close the door of the test chamber, set the parameter information of the sample thickness, test temperature, humidity, etc., and click the test option to start the test. The device automatically weighs the permeable cup automatically according to the set parameters.
(3) After the test, the equipment calculates and displays the water vapor transmission rate of the three samples according to the changes of the mass of the three moisture-permeable cups with time.
6. Test results
The results of the three samples tested in this test were 2186.7968 g / (m2 · 24h), 2076.4062 g / (m2 · 24h), 2092.4063 g / (m2 · 24h), and the water vapor transmission rate of the fiberboard sample Take the average value of the test results of three samples 2118.5364 g / (m2 · 24h).
7. Conclusion
This paper introduces a kind of moisture-proof performance that can reflect the fiberboard under the condition of 90% RH through the test of the water vapor transmission rate of the fiberboard sample. The test process is simple, the equipment is easy to operate, the test efficiency is high, and the accuracy of the test results is high. The repeatability is good. According to the actual application, the equipment described in this article can also be used to test the water vapor transmission rate of the fiberboard material under other humidity conditions. Jinan Languang Electromechanical Technology Co., Ltd. is a high-tech enterprise specializing in R & D and production of packaging testing equipment and packaging testing services. It has developed more than 100 sets of equipment that can be used to test the oxygen permeability, nitrogen permeability, carbon dioxide permeability of materials, To understand the related equipment information, such as water vapor transmission rate, tensile performance, impact resistance, friction coefficient, adhesive performance, sealing performance, heat seal strength, heat shrinkage performance, peel strength, total migration, etc. The more you understand, the more you trust! Labthink looks forward to enhancing technical communication and cooperation with enterprises and institutions in the industry!
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