A method for measuring the penetration depth of liquids in gypsum board

Abstract

The present application provides a method for measuring the penetration depth of a liquid in a gypsum board, the method comprising: contacting the test surface of the gypsum board with the liquid; the liquid is a liquid in which iodine is dissolved; obtaining a cross section perpendicular to the test surface of the gypsum board, applying a solution containing a substance that changes color when exposed to iodine to the cross section, and measuring the length of the discolored portion of the cross section, which is the penetration depth of the liquid in the gypsum board. The method provided by the present application is highly operable, can simply and directly observe the penetration depth of water, and improve the water resistance of water-resistant boards by analyzing the penetration behavior of the board core.

Description

Technical Field

[0001] The present invention relates to but is not limited to a building material testing technology, and in particular to but is not limited to a testing method for the water penetration depth after the water absorption test of the gypsum board surface. Background Art

[0002] Gypsum board is made of gypsum as the main raw material, with appropriate amount of additives and special paper as the surface. It is mainly used for indoor partitions and ceilings. However, due to the high solubility of gypsum and the many cracks and pores inside, ordinary gypsum has poor waterproof and moisture-proof properties. Water-resistant gypsum board core has water-repellent added and the surface paper is also composed of water-resistant surface paper. Therefore, water-resistant gypsum board can be used in areas with high humidity, such as toilets, showers and kitchens.

[0003] Surface water absorption is a key technical indicator to measure the water resistance of water-resistant gypsum board.

[0004] In the current water absorption test of water-resistant gypsum board, only the quality of gypsum board before and after water absorption is compared, and the penetration behavior of the board core is not studied. This makes it impossible for technicians to determine whether the gypsum core absorbs water and how much water is absorbed during the surface water absorption test, and it is also impossible to make targeted improvements to the board with unqualified surface water absorption. Therefore, it is crucial to study the water penetration behavior during the surface water absorption test. Summary of the invention

[0005] The following is a summary of the subject matter described in detail herein. This summary is not intended to limit the scope of the claims.

[0006] An embodiment of the present application provides a method for measuring the penetration depth of a liquid in a gypsum board, comprising:

[0007] contacting the test surface of the gypsum board with the liquid;

[0008] The liquid is a liquid in which iodine is dissolved;

[0009] Obtain a cross section perpendicular to the test surface of the gypsum board, apply a solution containing a substance that changes color when exposed to iodine to the cross section, and measure the length of the discolored portion of the cross section, which is the penetration depth of the liquid in the gypsum board.

[0010] In an embodiment provided in the present application, the liquid is a liquid in which elemental iodine is dissolved and iodized salt is also dissolved; the weight ratio of the iodized salt to the elemental iodine is (2 to 5):1.

[0011] In one embodiment provided in the present application, the concentration of elemental iodine in the liquid is no more than 10 g / L.

[0012] In an embodiment provided in the present application, the iodized salt is selected from any one or more of potassium iodide and sodium iodide;

[0013] In one embodiment provided in the present application, the iodine element and the iodine salt are configured into a solution in the liquid, and the temperature of the solution is 25±5° C.;

[0014] In one embodiment provided in the present application, the substance that changes color when exposed to iodine is starch.

[0015] In one embodiment provided in the present application, the concentration of the solution containing the substance that changes color when exposed to iodine is 5wt.% to 10wt.%.

[0016] In one embodiment provided in the present application, the liquid is water.

[0017] In an embodiment provided in the present application, the gypsum board is a paper-faced gypsum board.

[0018] In an embodiment provided in the present application, after removing the protective paper at the cross section, a solution containing a substance that changes color when exposed to iodine is applied to the cross section, and the length of the color-changed portion of the cross section is measured within two minutes after applying the solution containing a substance that changes color when exposed to iodine.

[0019] In one embodiment provided in the present application, the length of the color-changing portion of the cross section is measured within two minutes after a solution containing a substance that changes color when exposed to iodine is applied to the cross section.

[0020] In one embodiment provided in the present application, after testing the surface water absorption of the gypsum board according to the surface water absorption test method of the gypsum board in the Chinese national standard GB / T9775-2008, the penetration depth of the water absorbed by the gypsum board in the water absorption test into the gypsum board is measured.

[0021] In one embodiment provided in the present application, the water used in the test method for surface water absorption of gypsum board in the Chinese national standard GB / T9775-2008 contains iodine.

[0022] Other features and advantages of the present application will be described in the following description, and partly become apparent from the description, or be understood by implementing the present application. Other advantages of the present application can be invented and obtained by the schemes described in the description. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings are used to provide an understanding of the technical solution of the present application and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the technical solution of the present application and do not constitute a limitation on the technical solution of the present application.

[0024] Figure 1 Schematic diagram of measuring the penetration depth of water in Example 1, from Figure 1 It can be seen that part of the cross section of the gypsum board has turned blue, and the blue core of the board is the part of the core that has been penetrated by the iodine-containing aqueous solution.

[0025] Figure 2 The penetration depth of water in the gypsum board measured in Example 1 is shown in FIG.

[0026] Figure 3 The penetration depth of water in the gypsum board measured in Example 2.

[0027] Figure 4 Schematic diagram of measuring the penetration depth of water in Example 3, from Figure 4 It can be seen that part of the cross section of the gypsum board has turned blue, and the blue core of the board is the part of the core that has been penetrated by the iodine-containing aqueous solution.

[0028] Figure 5 The penetration depth of water in the gypsum board measured in Example 3.

[0029] Figure 6 The penetration depth of water in the gypsum board was measured for Comparative Example 1. Figure 6 It can be seen that the entire cross-section of the gypsum board turns blue. Too much iodine will cause smudges. Although it will not affect the surface water absorption, it will affect the judgment of the penetration depth.

[0030] Figure 7 This is a schematic diagram showing that the red pigment in comparative example 2 cannot penetrate the face paper.

[0031] Figure 8 This is a schematic diagram of the cross-section of the core of the paper-faced gypsum board in comparative example 2, in which the red pigment cannot penetrate the protective paper.

[0032] Fig. 9 This is a schematic diagram of comparative example 3, in which the methyl orange indicator does not penetrate the facing paper and the hydrochloric acid solution does not change color when applied to the cross section of the paper-faced gypsum board.

[0033] Fig.10 This is a schematic diagram showing that the methyl orange indicator in comparative example 3 cannot penetrate the face paper. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solution and advantages of the present application more clear, the embodiments of the present application are described in detail below. It should be noted that the embodiments and features in the embodiments of the present application can be combined with each other arbitrarily without conflict.

[0035] Example 1

[0036] (1) Potassium iodide and iodine are mixed and dissolved in water to prepare a solution in which the concentration of iodine in water is 3 g / L, the weight ratio of potassium iodide to iodine is 3:1, and the solution temperature is 25° C.; starch is added into water and stirred to prepare a starch solution with a concentration of 8 wt.%, wherein the starch is purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., brand S116030.

[0037] (2) Pour the iodine solution into the cylinder of the surface water absorption tester. The height of the iodine solution in the cylinder of the surface water absorption tester is 25 mm. Perform the surface water absorption test in accordance with the Chinese national standard GB / T9775-2008 paper-faced gypsum board surface water absorption test method.

[0038] (3) After the 2h test, use neutral filter paper to absorb the attached water on the surface of the test piece, remove the paper-faced gypsum board and cut it from the center, and use a wallpaper knife to carefully remove the layer of protective paper that contacts the iodine solution. Then use a brush to take a small amount of starch solution and evenly apply it on the cross section of the board core.

[0039] (4) Observe the board core within 2 minutes and measure the color depth with a ruler. This depth is the penetration depth of water in the gypsum board core.

[0040] Example 2

[0041] (1) Potassium iodide and iodine are mixed and dissolved in water to prepare a solution in which the concentration of iodine in water is 10 g / L, the weight ratio of potassium iodide to iodine is 3:1, and the solution temperature is 25° C.; starch is added into water and stirred to prepare a starch solution with a concentration of 5 wt.%, wherein the starch is purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., brand S116030.

[0042] (2) Pour the iodine solution into the cylinder of the surface water absorption tester. The height of the iodine solution in the cylinder of the surface water absorption tester is 25 mm. Perform the surface water absorption test in accordance with the Chinese national standard GB / T9775-2008 paper-faced gypsum board surface water absorption test method.

[0043] (3) After the 2h test, use neutral filter paper to absorb the attached water on the surface of the test piece, remove the paper-faced gypsum board and cut it from the center, and use a wallpaper knife to carefully remove the layer of protective paper that contacts the iodine solution. Then use a brush to take a small amount of starch solution and evenly apply it on the cross section of the board core.

[0044] (4) Observe the board core within 2 minutes and measure the color depth with a ruler. This depth is the penetration depth of water in the gypsum board core.

[0045] Example 3

[0046] The difference between this embodiment and embodiment 1 is that the gypsum board has the same face paper but a different core composition from that of embodiment 1, and the remaining components and experimental methods are the same as those of embodiment 1.

[0047] Comparative Example 1

[0048] The difference between this comparative example and Example 1 is that potassium iodide and elemental iodine are mixed and dissolved in water to prepare a concentration of elemental iodine in water of 20 g / L, the weight ratio of potassium iodide to elemental iodine is 3:1, and the remaining components and experimental methods are the same as those in Example 1.

[0049] Comparative Example 2

[0050] The difference between this comparative example and Example 1 is only: do not use starch and iodine solution, red pigment (red pigment is purchased from Jiukesong flagship store, and product number is 28527237308) is dissolved in water (concentration of red pigment in water is 10g / L). Then the pigment solution is poured in the surface water absorption tester cylinder, and height is 25mm, and then the surface water absorption test is carried out according to the Chinese national standard GB / T9775-2008 paper face gypsum board surface water absorption test method. After the surface water absorption 2h test ends, absorb the attached water of test piece surface with neutral filter paper, the paper face gypsum board is taken off and broken apart from the center, and the pigment penetration depth is observed.

[0051] Comparative Example 3

[0052] The difference between this comparative example and Example 1 is that starch and iodine solution are not used, but the reaction of methyl orange indicator turning red when exposed to acid is used. 0.1 g / L methyl orange solution is used to replace iodine solution. 0.001 mol / L hydrochloric acid is used to replace starch solution.

[0053] The experimental results are shown in Table 1.

[0054] Table 1 Test results

[0055]

[0056]

[0057] The experimental results show that the test method provided in this application will not affect the test results of the surface water absorption of the waterproof board.

[0058] The test method provided in this application can intuitively observe the water penetration behavior in the board core. Experiments show that the board core absorbs water during the water absorption of the surface of the water-resistant board. And the water penetration behavior of different types of water-resistant boards during the surface water absorption test is different. From the experimental results of Example 1 and Example 3, it can be intuitively seen that the water penetration depth of gypsum boards with different surface water absorption is significantly different. Example 3 has a large surface water absorption, and the water penetration depth in the board core is deeper.

[0059] The water penetration depth of Example 3 is 3 mm, which is greater than 2 mm of Example 1. Since the protective paper used in the water-resistant boards of Example 1 and Example 3 is the same, this result can remind technicians to make targeted modifications to the board core to increase the surface water absorption (the surface water absorption of Example 3 is greater than 160 g / m 2 , does not meet the Chinese national standard GB / T9775-2008), the surface water resistance of the unqualified water-resistant board.

[0060] This method is simple to operate and has a highly stable result. Compared with other methods, there will be no smudging or the color will not penetrate the protective paper.

[0061] The method proposed in the present application is highly operable, and can simply and directly observe the penetration depth of water, and improve the water resistance of the water-resistant board by analyzing the penetration behavior of the board core.

Claims

1. A method for measuring the penetration depth of a liquid in a gypsum board, characterized in that: include: contacting the test surface of the gypsum board with the liquid; The liquid is a liquid in which iodine is dissolved; Obtain a cross section perpendicular to the test surface of the gypsum board, apply a solution containing a substance that changes color when exposed to iodine to the cross section, and measure the length of the discolored portion of the cross section, which is the penetration depth of the liquid in the gypsum board; The gypsum board is a paper-faced gypsum board; The liquid is a liquid in which iodine element is dissolved and iodized salt is dissolved; The weight ratio of the iodized salt to the iodine element is (2 to 5): 1 The concentration of elemental iodine in the liquid is no more than 10 g / L.

2. The method for measuring the penetration depth of liquid in gypsum board according to claim 1, characterized in that: The substance that changes color when exposed to iodine is starch.

3. The method for measuring the penetration depth of liquid in gypsum board according to claim 1, characterized in that: The concentration of the solution containing the substance that changes color when exposed to iodine is 5 wt.% to 10 wt.%.

4. The method for measuring the penetration depth of liquid in a gypsum board according to any one of claims 1 to 3, characterized in that: The liquid is water.

5. The method for measuring the penetration depth of liquid in gypsum board according to claim 4, characterized in that: After removing the protective paper at the cross section, a solution containing a substance that changes color when exposed to iodine is applied to the cross section, and the length of the discolored portion of the cross section is measured within two minutes after applying the solution containing a substance that changes color when exposed to iodine.

6. The method for measuring the penetration depth of liquid in a gypsum board according to any one of claims 1 to 3, characterized in that: The length of the discolored portion of the cross section is measured within two minutes after a solution containing a substance that changes color when exposed to iodine is applied to the cross section.

7. The method for measuring the penetration depth of liquid in a gypsum board according to any one of claims 1 to 3, characterized in that: After testing the surface water absorption of the gypsum board according to the test method for surface water absorption of the gypsum board in the Chinese national standard GB / T9775-2008, the penetration depth of the water absorbed by the gypsum board in the water absorption test into the gypsum board is measured.

8. The method for measuring the penetration depth of liquid in gypsum board according to claim 7, characterized in that: The water used in the test method for the surface water absorption of gypsum board in the Chinese national standard GB / T9775-2008 contains iodine.

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