JPH0354300B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a humidity measuring material for measuring humidity on various solid surfaces, such as concrete subsurfaces, and a method for manufacturing the same, and is particularly suitable for use at construction sites, etc. The present invention relates to a humidity measuring material that can be used for measuring humidity and a method for manufacturing the same.

(Prior art and its problems) The humidity measuring material according to the present invention can be used to measure moisture on the surface of various structures and solid substances.

For example, when pouring concrete for repair on the surface (base) of a concrete structure, applying finishing materials or paint, or forming a waterproof layer, problems such as poor adhesion or blistering may occur at a later date. Peeling of the paint film may be observed.

It is thought that one of the factors behind the occurrence of such a situation is the moisture content or humidity of the underlying surface. In other words, in order to prevent construction defects such as those mentioned above, one of the measures is to check the moisture content of the subsurface at the time of construction and adjust the components and composition of concrete for pouring and finishing materials. However, the reality is that there are no humidity measuring materials that can be easily used at construction sites.

(Object of the Invention) Accordingly, the object of the present invention is to easily and quickly process solid surfaces such as concrete subsurfaces at construction sites without using special equipment or requiring special skill. An object of the present invention is to provide a humidity measuring material capable of measuring the amount of water and a method for manufacturing the same.

(Means and operations for solving the problem and achieving the purpose) In view of the problems described above in the prior art, the present inventors have proposed a method that can be easily used at a construction site,
We conducted extensive research in order to develop a humidity measuring material for use in measuring moisture in concrete substrates that has quantitative measurement accuracy and results, and is therefore highly reliable.

That is, we searched for reagents that develop or change color due to water absorption, and ultimately conducted various experiments using basic dyes as the reagent. First, by combining a single basic dye with various water-absorbing agents, moisture is transferred from the concrete subsurface to the water-absorbing agent, and whether there is a difference in the degree of coloration depending on the amount of water absorbed by the water-absorbing agent. When investigating this issue, it was found that the color density of the basic dye changes in response to the amount of water absorbed. This suggests that basic dyes can be used to measure the moisture content of concrete subsurfaces. Therefore, we investigated various basic dyes and conducted experiments using various water absorbing agents, but the amount of water absorbed and the degree of concentration change were extremely subtle.
It has become clear that it is difficult to determine the moisture content of a concrete subsurface from the color density unless optical equipment is used.

Therefore, the inventors of the present invention abandoned the use of a single basic dye, and made further studies by blending two types of basic dyes to form a coloring agent, and combining this with a water absorbing agent. That is, a first basic dye that changes color to a certain fixed color tone in a certain water absorption amount range and then maintains the above color change color tone even if the water absorption amount changes, and a color change absorption area of the first basic dye. If a second basic dye is used, which changes color to a constant and different color tone from the above-mentioned color tone in an absorption area close to We conducted various experiments based on the assumption that it would be possible to bring about gradual changes in the color tone, and we found that if brilliant green and crystal violet were used as basic dyes, the results as predicted above could be obtained. It turned out that it was possible.

Further, as the present inventors continued their research, they found that the above-mentioned first basic dye and second basic dye were blended to form a coloring agent, and this and a water absorbing agent were combined to form a coloring agent in methanol of acid. We were able to develop a humidity measuring material that prepares a solution by adding it to a solution, immerses a liquid adhesion member in this solution, and then dries it. In other words, according to this humidity measuring material, the color tone changes from orange to ocher, light green, green, black-green, and then to purple as the water absorption amount of the water absorption agent increases, and further as the water absorption amount decreases. The color tone changes in the opposite direction,
In other words, they discovered that the color changes reversibly.

The present invention is based on these findings, and
Its gist is ``a humidity measuring material characterized by a mixture of brilliant green and crystal violet as coloring agents, a water-absorbing agent, and an acid supported on the member'' and ``brilliant green and crystal violet as coloring agents''. Humidity characterized by immersing a liquid adhesion member for 2 to 3 seconds in a solution prepared by adding a mixture of water absorbing agent to a methanol solution of acid, and then drying at a temperature of 70 to 80°C. ``Measurement material manufacturing method.''

Brilliant green and crystal violet are used as the first and second basic dyes in the present invention, and one type of zinc bromide or magnesium perchlorate or a mixture of both is used as the water absorbing agent. As the acid, oxalic acid, sulfuric acid, etc. are used. Further, examples of the liquid-adhering member used in the present invention include filter paper, and the time for immersing this liquid-adhering member in the above prepared solution may be 2 to 3 seconds, and the temperature of the drying step is preferably 70 to 80°C. Note that the methanol content is volatilized by drying such a member to be adhered.

(Example) Next, the present invention will be explained in more detail using test examples of the present invention.

A) Preparation of coloring reagents Using special grade reagents, add zinc bromide as a water absorbing agent and brilliant green and crystal violet as coloring agents to a methanol solution of oxalic acid in the following proportions. A color reagent was prepared by adding equal amounts of the mixture and stirring.

Methanol solution of oxalic acid 78 (wt%) Water absorbing agent 20 Coloring agent 2 (Oxalic acid: methanol: 1:50) B) Preparation of humidity measuring material (test paper) Commercially available filter paper (No. 5B, for quantitative use, diameter 7 cm) was immersed in the above coloring reagent solution for 2-3 seconds, taken out, and then dried at 75°C to prepare a humidity measuring material.

Although drying may be done naturally at room temperature, rapid drying was performed by blowing heated air at 75°C. The color of the test strip thus obtained is orange. The obtained test paper was coated with a semi-permeable membrane (having air permeability but blocking moisture) coated with vinyl acetate adhesive on all four sides to prevent it from being affected by moisture from the outside air.
16 x 16 cm) and pack them individually on both sides and store them.

C) Moisture absorption test Remove the test paper obtained in section B above from the pack, leave it in a thermostatic chamber, and adjust the humidity in the chamber to 60-100%.
Changed to RH.

The test paper absorbs the moisture in the thermostatic chamber and changes its color from its initial orange color to ocher, pale green, green, black-green, and then purple, so at each time the paper changes color, The water absorption rate of the test paper was examined.

D) Results and discussion The results are shown in graph b in Figure 1 (formulation in Figure 1
As shown in B2), it was found that there was a relatively good correlation between the coloration or discoloration tone of the test paper and the water absorption rate.

When a test paper that has changed color to a certain tone is left to dry or is forced to dry, the color changes reversibly from purple to black-green, green, pale green, ocher, and then orange. Humidity could be determined by looking at the state of discoloration.

Furthermore, various coloring reagents were prepared by increasing or decreasing the amount of water-absorbing agent to 15% and 25% while keeping the same amounts of coloring agent, acid, and methanol, and immersing filter paper in each of these coloring reagents. When the moisture absorption test was carried out in the same manner as above, the test using the coloring reagent prepared by increasing the amount of water absorbing agent to 25%. In the case of paper, the rate of moisture absorption increases and the color tone changes quickly, and as shown in graph c in Figure 1 (Formulation B3 in Figure 1), the variation increases and the measurement accuracy decreases.
It has been found that excessive use of the water absorbing agent is undesirable, as this leads to a decrease in reliability. On the other hand, in the case of a test paper using a coloring reagent prepared by reducing the amount of water-absorbing agent to 15%, the moisture absorption rate decreases and the color change slows down, as well as graph a in Figure 1 (graph 1). As shown in formulation B1) in the figure, it was found that it is not preferable to use too little of the water-absorbing agent, as the variation becomes somewhat large and the measurement accuracy and reliability decrease.

In addition, Fig. 2 shows the humidity measuring material (test paper) according to the present invention at a temperature of 20°C and a relative humidity of 60 to 100% RH.
This is a graph showing the results of investigating the relationship between the color tone change of the test paper that changes color due to moisture absorption and release and the water absorption rate of the test paper, after repeating 4 cycles of changing the humidity from 100% RH back to 60% RH.

(Effects of the Invention) According to the humidity measuring material of the present invention, if something in the form of a test paper is kept in contact with a solid surface such as a concrete base surface for a short period of time, the test paper changes color depending on the amount of water absorbed. Therefore, the moisture content of the solid surface can be easily and quickly determined from the color change tone.

Furthermore, since the humidity measuring material of the present invention reversibly changes color in response to changes in humidity, the humidity of the object to be measured can be determined by looking at the state of the color change.

Therefore, it can be said that the present invention has great practical value.

[Brief explanation of drawings]

Figure 1 shows a humidity measuring material (test paper) according to the present invention.
was placed in a thermostatic chamber maintained at a temperature of 20℃ and a relative humidity of 65%, and the humidity inside the chamber was changed from 60 to 100% RH.The test paper changed color due to moisture absorption, and the test paper absorbed water. It is a graph showing the results of examining the relationship with the rate. In addition, Figure 2 shows the humidity measuring material (test paper) according to the present invention at a temperature of 20°C and a relative humidity of 60 to 100% RH.
This is a graph showing the results of investigating the relationship between the color tone change of the test paper that changes color due to moisture absorption and release and the water absorption rate of the test paper, after repeating 4 cycles of changing the humidity from 100% RH back to 60% RH.

Claims (1)

[Scope of Claims] 1. A humidity measuring material comprising a member carrying a mixture of brilliant green and crystal violet as a coloring agent, a water absorbing agent, and an acid. 2. Dip the liquid-adhering member for 2 to 3 seconds in a solution prepared by adding a water-absorbing agent to a mixture of brilliant green and crystal violet as a coloring agent to a methanol solution of acid, and then heat to 70°C. A method for producing a humidity measuring material characterized by drying at ~80℃.