How to check the water damage history of paperboard

Abstract

To confirm a water wetting history of a paperboard.SOLUTION: A confirmation method of a water wetting history of a paperboard, includes a process of spraying an aqueous solution of methanol or ethanol with a concentration of 10% or more and 20% or less on the surface of the paperboard, and a process of visually checking within 5 minutes after the spraying of the aqueous solution whether or not the surface of the paperboard exhibits color shading due to the difference in penetration of the aqueous solution.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a method for checking the water wetting history of paperboard. [Background technology]

[0002] Gypsum board is a building material made of gypsum covered with paperboard (Patent Document 1), and is widely used as a building material because it is inexpensive yet very strong, and has high thermal and sound insulation properties, and there are various types to suit different applications. Paperboard is also used on the front and back of cardboard. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-82487 Summary of the Invention [Problem to be solved by the invention]

[0004] If paperboard gets wet for some reason, the water evaporates over time, making it impossible to visually check whether it has been wet. This tendency is particularly pronounced when it comes to water from taps, as tap water contains few impurities.

[0005] The present invention aims to confirm the water wetting history of paperboard. [Means for solving the problem]

[0006] The method for checking the water wetting history of paperboard comprises the steps of spraying an aqueous solution of methanol, ethanol, or isopropanol at a predetermined concentration of 10% or more onto the surface of the paperboard, and visually checking within 5 minutes of spraying the aqueous solution to see if any color shading appears on the surface of the paperboard due to differences in penetration of the aqueous solution.

[0007] According to the present invention, the sprayed water is not pure water, so the water itself does not indicate a history of water wetting. The inventors have found through experiments the optimum concentration for checking the water wetting history of paperboard. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram of a physical change model of cellulose fibers. [Figure 2] 1 is a photograph showing the paperboard used in the experiment. [Figure 3] This photo was taken 5 minutes after spraying with a 20% methanol aqueous solution. [Figure 4] This photo was taken 5 minutes after spraying a 40% methanol aqueous solution. [Figure 5] This photo was taken 5 minutes after spraying with a 20% ethanol aqueous solution. [Figure 6] This photo was taken 5 minutes after spraying with a 40% ethanol aqueous solution. [Figure 7] This is a photograph taken 5 minutes after spraying with a 10% aqueous isopropanol solution. [Figure 8] This photograph was taken 5 minutes after spraying with a 15% aqueous solution of isopropanol. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Elements with the same reference numerals in all the drawings have the same or equivalent functions, and their repeated explanation will be omitted. Note that the size of the figures does not necessarily correspond to the magnification.

[0010] If the paperboard of gypsum board, a type of building material, or the paperboard of cardboard, which is widely used as packaging material, becomes wet for some reason, the moisture evaporates over time, making it impossible to visually check whether or not it is wet. This tendency is particularly pronounced when the material is submerged in tap water (tap water), as there is little impurity in the material. In this embodiment, the gypsum board base paper that covers the gypsum of the gypsum board and the liner that is attached to the core (corrugated paper) of the cardboard are both considered to be paperboard.

[0011] Paperboard is made primarily from recycled paper, such as newspapers and cardboard. The main component of the paper that makes up newspapers and cardboard is pulp fiber, which is primarily made up of polysaccharides, most of which is cellulose. Figure 1 shows a model of the physical changes that occur in cellulose molecules. Once paper is immersed in water, the molecular structure of the cellulose fiber changes due to the water molecules. It is thought that the disruption of bonds causes changes in the permeability characteristics. The inventors of this application conducted experiments, thinking that this could be used to confirm the water wetting history of paperboard.

[0012] In the experiment, gypsum board base paper and cardboard base paper liners C5, K5, K5 white, and K6 were used (Fig. 2). According to JIS P 3902, which specifies liners, C5 is a paper quality with a recycled paper content of 90% or more and a weight of 160g to 170g / m 2 K5 is a paper with a recycled paper content of 50% or more, and is 170g-180g / m 2 K6 is a paper with a recycled paper content of 50% or more and weighs 210g to 220g / m 2 The thickness was set to 100mm x 100mm. The surface of K5 White is white, and the surface of the other paperboard is kraft color. The paperboard was cut to 100mm x 100mm and used.

[0013] First, 500 μL of tap water was dropped onto the paperboard, and the paperboard was allowed to naturally absorb water and dry at 25°C to create a water-wet condition. Methanol, ethanol, and isopropanol, which are monohydric alcohols with high solubility in water, were then dissolved in water at specified ratios. The ethanol concentrations were 0, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, and 70%, while the methanol and isopropanol concentrations were 0, 10, 15, 20, 25, 30, 35, and 40%. Pure water was used as the solvent.

[0014] The solution was sprayed evenly with a spray bottle, and visual observation was performed. Specifically, visual observation was performed to see if any color shading appeared on the surface of the paperboard due to differences in penetration of the solution. Observations were performed before spraying, immediately after spraying, 30 seconds after spraying, and 5 minutes after spraying.

[0015] For example, Figure 3 is a photograph taken 5 minutes after spraying a 20% aqueous methanol solution. Figure 4 is a photograph taken 5 minutes after spraying a 40% aqueous methanol solution. Figure 5 is a photograph taken 5 minutes after spraying a 20% aqueous ethanol solution. Figure 6 is a photograph taken 5 minutes after spraying a 40% aqueous ethanol solution. Figure 7 is a photograph taken 5 minutes after spraying a 10% aqueous isopropanol solution. Figure 8 is a photograph taken 5 minutes after spraying a 15% aqueous isopropanol solution.

[0016] The experimental results are shown in the following table. In the table, ◯ indicates that the product was visible from immediately after spraying until 5 minutes later, △ indicates that the product was visible for 30 seconds immediately after spraying but was difficult to see after 5 minutes, and × indicates that the product was difficult to see immediately after spraying.

[0017] [Table 1]

[0018] In experiments conducted on gypsum board base paper, visual confirmation was possible with aqueous methanol or ethanol solutions at concentrations of 0 to 40%, and with aqueous isopropanol solutions at concentrations of 0 to 15%.

[0019] [Table 2]

[0020] In experiments conducted on liner C5 cardboard, visual confirmation was possible with aqueous methanol or ethanol solutions at concentrations of 0 to 30%, and with aqueous isopropanol solutions at concentrations of 0 to 15%.

[0021] [Table 3]

[0022] In experiments conducted on liner K5 cardboard, visual confirmation was possible with aqueous methanol solutions at concentrations of 0 to 30%, aqueous ethanol solutions at concentrations of 0 to 20%, and aqueous isopropanol solutions at concentrations of 0 to 10%.

[0023] [Table 4]

[0024] In an experiment conducted on liner K5 white cardboard, visual confirmation was possible with aqueous methanol solutions at concentrations of 0-25%, with aqueous ethanol solutions at concentrations of 0-20%, but with aqueous isopropanol solutions at concentrations of 10% or higher.

[0025] [Table 5]

[0026] In experiments conducted on liner K6 cardboard, visual confirmation was possible with aqueous methanol solutions at concentrations of 0 to 30%, with aqueous ethanol solutions at concentrations of 0 to 20%, and with isopropanol solutions at concentrations of 0 to 10%.

[0027] In addition, for the 0% concentration (pure water), visual confirmation was possible in all cases, but it was found that the surface of all paperboards became distorted over time after spraying, making them unusable thereafter.

[0028] From the above experimental results, the following method was found to confirm the water wetting history of paperboard.

[0029] (1) A method for checking the water wetting history of paperboard includes the steps of spraying an aqueous solution of methanol or ethanol at a concentration of 10% to 20% onto the surface of the paperboard, and visually checking within 5 minutes of spraying the aqueous solution to see if any color shading appears on the surface of the paperboard due to differences in penetration of the aqueous solution.

[0030] (2) A method for checking the water wetting history of paperboard includes the steps of spraying an aqueous solution of methanol at a concentration of 10% to 25% onto the surface of the paperboard, and visually checking within 5 minutes of spraying the aqueous solution to see if any color shading appears on the surface of the paperboard due to differences in penetration of the aqueous solution.

[0031] (3) In the method for checking the water wetting history of paperboard described in (1) or (2), the paperboard may be a gypsum board base paper.

[0032] (4) In the method for checking the water wetting history of paperboard described in (1) or (2), the paperboard is a liner of a corrugated cardboard base paper, and the paper quality and thickness of the liner are C5 (recycled paper content of 90% or more; 160 g to 170 g / m 2 ) may be characterized in that

[0033] (5) In the method for checking the water wetting history of paperboard described in (1) or (2), the paperboard is a liner of a corrugated cardboard base paper, and the paper quality and thickness of the liner are K5 (recycled paper content of 50% or more; 170 g to 180 g / m 2 ) may be characterized in that

[0034] (6) In the method for checking the water wetting history of paperboard described in (1) or (2), the paperboard is a liner of a corrugated cardboard base paper, the surface of the liner is white, and the paper quality and thickness of the liner are K5 (recycled paper content of 50% or more; 170 g to 180 g / m 2 ) may be characterized in that

[0035] (7) In the method for checking the water wetting history of paperboard described in (1) or (2), the paperboard is a liner of a corrugated cardboard base paper, and the paper quality and thickness of the liner are K6 (recycled paper content of 50% or more; 210 g to 220 g / m 2 ) may be characterized in that

[0036] (8) A method for checking the water wetting history of paperboard includes the steps of spraying an aqueous solution of ethanol at a concentration of 10% to 25% onto the surface of the paperboard, and visually checking within 5 minutes from the spraying of the aqueous solution whether a color difference appears on the surface of the paperboard due to a difference in penetration of the aqueous solution, wherein the paperboard is a liner of gypsum board base paper or corrugated cardboard base paper, and the paper quality and thickness of the liner are C5 (recycled paper content of 90% or more; 160 g to 170 g / m 2 )

[0037] (9) A method for checking the water wetting history of paperboard includes the steps of spraying a methanol aqueous solution at a concentration of 10% to 30% onto the surface of the paperboard, and visually checking within 5 minutes from the spraying of the aqueous solution whether a color difference appears on the surface of the paperboard due to a difference in penetration of the aqueous solution, wherein the paperboard is a liner of gypsum board base paper or corrugated cardboard base paper, and the paper quality and thickness of the liner are C5 (recycled paper content of 90% or more; 160 g to 170 g / m 2 ), K5 (recycled paper content 50% or more; 170g-180g / m2 ) or K6 (recycled paper content 50% or more; 210g-220g / m 2 )

[0038] (10) A method for checking the water wetting history of paperboard includes the steps of spraying an aqueous solution of ethanol at a concentration of 10% to 30% onto the surface of the paperboard, and visually checking within 5 minutes from the spraying of the aqueous solution whether a color difference appears on the surface of the paperboard due to a difference in penetration of the aqueous solution, wherein the paperboard is a liner of gypsum board base paper or corrugated cardboard base paper, and the paper quality and thickness of the liner are C5 (recycled paper content of 90% or more; 160 g to 170 g / m 2 )

[0039] (11) A method for checking the water wetting history of a paperboard includes the steps of spraying an aqueous solution of methanol or ethanol at a concentration of 10% to 40% onto the surface of the paperboard, and visually checking within 5 minutes of spraying the aqueous solution to see if any color shading appears on the surface of the paperboard due to differences in penetration of the aqueous solution, wherein the paperboard is gypsum board base paper.

[0040] (12) A method for checking the water wetting history of paperboard includes the steps of spraying an aqueous solution of isopropanol at a concentration of 10% to 15% onto the surface of the paperboard, and visually checking within 5 minutes from the spraying of the aqueous solution whether a color difference appears on the surface of the paperboard due to a difference in penetration of the aqueous solution, wherein the paperboard is a liner of gypsum board base paper or corrugated cardboard base paper, and the paper quality and thickness of the liner are C5 (recycled paper content of 90% or more; 160 g to 170 g / m 2 )

[0041] The present invention is not limited to the above-described embodiments and various modifications are possible. For example, the configurations described in the embodiments can be replaced with substantially the same configurations, configurations that achieve the same effects, or configurations that can achieve the same objectives.

Claims

1. spraying an aqueous solution of methanol or ethanol at a concentration of 10% to 20% onto the surface of the paperboard; visually checking whether a color difference occurs on the surface of the paperboard due to a difference in penetration of the aqueous solution within 5 minutes after spraying the aqueous solution; A method for checking the water wetting history of paperboard, comprising:

2. spraying an aqueous solution of methanol at a concentration of 10% to 25% onto the surface of the paperboard; visually checking whether a color difference occurs on the surface of the paperboard due to a difference in penetration of the aqueous solution within 5 minutes after spraying the aqueous solution; A method for checking the water wetting history of paperboard, comprising:

3. The method for checking the water wetting history of paperboard according to claim 1 or 2, The method for checking the water wetting history of paperboard, wherein the paperboard is gypsum board base paper.

4. The method for checking the water wetting history of paperboard according to claim 1 or 2, the paperboard is a liner for a corrugated board; The paper quality of the liner has a recycled paper content of 90% or more, The thickness of the liner is 160g to 170g / m ２ A method for checking the water wetting history of paperboard, characterized by:

5. The method for checking the water wetting history of paperboard according to claim 1 or 2, the paperboard is a liner for a corrugated board; The paper quality of the liner has a recycled paper content of 50% or more, The thickness of the liner is 170g to 180g / m ２ A method for checking the water wetting history of paperboard, characterized by:

6. The method for checking the water wetting history of paperboard according to claim 1 or 2, the paperboard is a liner for a corrugated board; The paper quality of the liner has a recycled paper content of 50% or more, the surface of the liner is white; The thickness of the liner is 170g to 180g / m ２ A method for checking the water wetting history of paperboard, characterized by:

7. The method for checking the water wetting history of paperboard according to claim 1 or 2, the paperboard is a liner for a corrugated board; The paper quality of the liner has a recycled paper content of 50% or more, The thickness of the liner is 210 g to 220 g / m ２ A method for checking the water wetting history of paperboard, characterized by:

8. spraying an aqueous solution of ethanol at a concentration of 10% to 25% onto the surface of the paperboard; visually checking whether a color difference occurs on the surface of the paperboard due to a difference in penetration of the aqueous solution within 5 minutes after spraying the aqueous solution; Including, The paperboard is a liner for gypsum board or corrugated board, The paper quality of the liner has a recycled paper content of 90% or more, The thickness of the liner is 160g to 170g / m ２ A method for checking the water wetting history of paperboard, characterized by:

9. spraying an aqueous solution of methanol at a concentration of 10% to 30% onto the surface of the paperboard; visually checking whether a color difference occurs on the surface of the paperboard due to a difference in penetration of the aqueous solution within 5 minutes after spraying the aqueous solution; Including, The paperboard is a liner for gypsum board or corrugated board, The paper quality and thickness of the liner is 160g to 170g / m with a recycled paper content of 90% or more. ２ , recycled paper content is 50% or more and 170g to 180g / m ２ Or recycled paper content is 50% or more and 210g to 220g / m ２ A method for checking the water wetting history of paperboard, characterized by:

10. spraying an aqueous solution of ethanol at a concentration of 10% to 30% onto the surface of the paperboard; visually checking whether a color difference occurs on the surface of the paperboard due to a difference in penetration of the aqueous solution within 5 minutes after spraying the aqueous solution; Including, The paperboard is a liner for gypsum board or corrugated board, The paper quality of the liner has a recycled paper content of 90% or more, The thickness of the liner is 160g to 170g / m ２ A method for checking the water wetting history of paperboard, characterized by:

11. spraying an aqueous solution of methanol or ethanol at a concentration of 10% to 40% onto the surface of the paperboard; visually checking whether a color difference occurs on the surface of the paperboard due to a difference in penetration of the aqueous solution within 5 minutes after spraying the aqueous solution; Including, The method for checking the water wetting history of paperboard, wherein the paperboard is gypsum board base paper.

12. spraying an aqueous solution of isopropanol at a concentration of 10% to 15% onto the surface of the paperboard; visually checking whether a color difference occurs on the surface of the paperboard due to a difference in penetration of the aqueous solution within 5 minutes after spraying the aqueous solution; Including, The paperboard is a liner for gypsum board or corrugated board, The paper quality of the liner has a recycled paper content of 90% or more, The thickness of the liner is 160g to 170g / m ２ A method for checking the water wetting history of paperboard, characterized by:

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