Coating material and structure containing roof tile chip and magnesia cement

Abstract

To provide a novel coating material that can be coated on an exterior of a structure etc. to impart impact resistance and the like, and a structure coated with the coating material.SOLUTION: The coating material comprises roof tile chips and magnesia cement. A structure has a surface coated with the coating material. Or a structure has an earthen wall coated with the coating material.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a coating material and a structure containing roof tile chips and magnesia cement. [Background technology]

[0002] As earthen walls deteriorate over time, their adhesive strength gradually decreases, causing them to crumble and fall off. The main cause of this is the gradual decrease in adhesive strength due to the effects of ultraviolet rays, etc., which causes the soil to crumble and fall off with even the slightest impact. The lifespan of conventional earthen walls is such that dirt becomes noticeable after about 10 years, as they cannot be wiped with water. In addition, not only does the appearance of the wall deteriorate, but frequent cleaning is also a major disadvantage. For example, Patent Document 1 discloses a treatment agent and method for preventing earthen walls from chipping. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-108331 Summary of the Invention [Problem to be solved by the invention]

[0004] In order to extend the life of earthen walls, the strength of the surface coating material for earthen walls is also an important factor. The object of the present invention is to provide a new coating material that can be applied to the exterior of a structure to impart impact resistance, etc., and to provide a structure coated with the coating material. [Means for solving the problem]

[0005] The present inventors have conducted extensive research to solve the above problems, and as a result have found that the following invention meets the above object, thereby completing the present invention.

[0006] That is, the present invention relates to the following inventions. <1> A coating material containing roof tile chips and magnesia cement. <2> In the coating material, the magnesia cement is contained in an amount of 5 to 30 parts by mass per 100 parts by mass of the roof tile chips. <1> The coating material described in <3> The aforementioned <1> or <2> A structure having a surface coated with the coating material described in 1. <4> The aforementioned <1> or <2> A structure having an earthen wall coated with the coating material described in 1. [Effects of the Invention]

[0007] According to the present invention, there is provided a novel coating material that can be applied to the exterior of a structure to impart impact resistance, etc. Also provided is a structure coated with the coating material. [Brief explanation of the drawings]

[0008] [Figure 1] This is a photograph of the waste roof tile chips used in the experiment. [Figure 2] This shows a photograph of a test specimen coated with a coating material at 7 days old in an impact resistance test. [Figure 3] This shows a photograph of a test specimen coated with a coating material at 28 days old in an impact resistance test. [Figure 4] FIG. 1 is a schematic diagram of a coating material sample used in an antibacterial activity test. DETAILED DESCRIPTION OF THE INVENTION

[0009] The following describes in detail an embodiment of the present invention, but the following description of the constituent elements is one example (typical example) of an embodiment of the present invention, and the present invention is not limited to the following content unless the gist of the present invention is changed. Note that when the expression "to" is used in this specification, it is used as an expression including the numerical values ​​or physical property values ​​before and after it.

[0010] <Painting materials> The present invention relates to a coating material containing roof tile chips and magnesia cement (hereinafter, sometimes referred to as the "coating material of the present invention"). The coating material of the present invention is applied to structures. For example, by applying the coating material of the present invention to the exterior of an earthen wall, the lifespan of the conventional earthen wall can be significantly extended. In addition, it can impart impact resistance, antibacterial properties, and moisture-regulating properties (moisture absorption and release).

[0011] [Tile chips] The coating material of the present invention contains tile chips. Tile chips are crushed and / or pulverized waste tiles (discarded tiles). Roof tiles are representative, but tiles are not limited to roof building materials and refer to any type of unglazed clay. The tile chips used in the coating material of the present invention are not limited to crushed and / or pulverized roof tiles, but also include crushed or pulverized tiles other than roof tiles. For example, Tecora (registered trademark) can be used as tile chips.

[0012] Most Japanese roofing tiles are made by baking clay and have the following characteristics: 1) Fire resistance: It is a non-flammable material so it is difficult to burn. 2) Waterproof performance: Because it is made of ceramic, it does not let water through. 3) Cold resistance: It is resistant to freezing, so it can last a long time even in cold regions. 4) Thermal insulation performance: Not only does it provide insulation, it also has heat-blocking properties and is highly breathable. 5) Earthquake resistance 6) Durability: High strength due to high temperature firing. 7) Soundproofing performance: The excellent soundproofing properties unique to roof tiles. 8) Comfort: It is cool in summer and warm in winter. In addition, because it is porous, it also has physical properties such as moisture absorption and breathability. In particular, Japanese roofing tiles stand out for their three distinctive features: high durability, high strength, and no maintenance required.

[0013] By including roof tile chips in the coating material of the present invention, it is possible to form a coating layer (a layer formed by the coating material after hardening) that has excellent impact resistance and the like due to the properties of the roof tile described above.

[0014] The roof tile chips contained in the coating material of the present invention are weakly alkaline, and preferably have a pH of 9 or less.

[0015] Furthermore, the roof tile chips contained in the coating material of the present invention preferably contain major elements such as phosphate, calcium, magnesium, and potassium. For example, the roof tile chips contained in the coating material of the present invention can contain 1-3% P2O5, 35-50% CaO, 1-3% MgO, and 1-4% K2O. This composition is preferable because it can be used as a supply material for these elements when recycling structures to which the coating material is applied. For example, it is expected to be used as an improvement material for agricultural land.

[0016] Furthermore, the roof tile chips contained in the coating material of the present invention preferably contain soluble copper, soluble zinc, and hot water soluble boron within the appropriate range for healthy soil in Japan, or in amounts greater than those found in healthy soil in Japan. This configuration allows them to be used as a supply material for these trace elements. Therefore, when structures to which the coating material is applied are recycled, they are expected to be used as an improvement material for agricultural land.

[0017] The roof tile chips are preferably finely pulverized, specifically, preferably 1 mm or less, 0.5 mm or less, or 0.2 mm or less in size, for example, 0.01 to 1 mm, 0.03 to 0.5 mm, or 0.05 to 0.2 mm in size.

[0018] [Magnesia cement] The coating material of the present invention contains magnesia cement, which acts as a hardening agent. Magnesia cement is a cement made by kneading light-burned magnesia (MgO), which is made by baking magnesium carbonate or magnesium hydroxide at temperatures below 1000°C, with a bittern solution (MgCl2 solution) and hardening it. Hardening occurs due to the formation of oxychloride salts.

[0019] Unlike calcium derived from limestone, which deteriorates over time, magnesia cement has the property of becoming harder with each passing year.

[0020] Magnesia cement has characteristics such as being stronger, having strong adhesive properties with other substances, antibacterial properties, and not allowing mold to grow, compared to Portland cement. It is an air-hardening cement that attains considerable strength in about 20 hours and continues to harden after that. This strength development occurs when soil is used, and the MgAl(OH) 14 XH2O and Mg4Al2(OH) 14 Reaction products of magnesium and aluminum, such as 3H2O, have been observed and are considered to be the factors that contribute to the strength of these high-quality clays (Source: Yamada Satoshi, 2015).

[0021] The coating material of the present invention may contain components other than roof tile chips, magnesia cement, and water. For example, magnesia cement has good adhesion to wood, and is therefore thought to be compatible with hemp, bamboo fiber, straw, Japanese paper, sawdust, and other materials that can be used as reeds, so the coating material may contain these.

[0022] The coating material of the present invention can also be made from roof tile chips, magnesia cement, and water. The coating material of the present invention with such a composition can have an excellent balance of impact resistance, crack resistance, ease of adhesion, antibacterial properties, etc.

[0023] In the coating material of the present invention, the blending ratio of roof tile chips and magnesia cement can be appropriately set taking into consideration impact resistance and the like, and is not particularly limited, but for example, 5 to 30 parts by mass, 5 to 25 parts by mass, or 10 to 20 parts by mass of magnesia cement per 100 parts by mass of roof tile chips is preferred. Increasing the amount of roof tile chips will result in excellent impact resistance and humidity control properties, but may also make cracks more likely to occur.

[0024] The coating material of the present invention is prepared by mixing roof tile chips, magnesia cement, and water, and applying the mixture in a fluid state to an object such as the surface of an earthen wall. The amount of water is adjusted to obtain an appropriate viscosity for each coating method. For example, the amount of water in the coating material of the present invention is 15 to 40% by mass or 15 to 30% by mass.

[0025] <Structure> The present invention also relates to a structure having the coating material of the present invention applied to its surface. When the coating material of the present invention is applied to the surface of a structure, the coating material of the present invention cures, resulting in a structure having a layer of the cured product of the coating material of the present invention formed on its surface. As shown in the examples below, the cured product of the coating material of the present invention has excellent impact resistance, antibacterial properties, and humidity-regulating properties, and can therefore impart these properties to the structure.

[0026] The coating material of the present invention can be applied by any known method, such as by applying the coating material to a wall surface using a spatula or the like.

[0027] There are no particular limitations on the object to which the coating material of the present invention is applied, but earthen walls are preferred, and a suitable example of a structure of the present invention is a structure having earthen walls coated with the coating material of the present invention.

[0028] As described above, the roof tile chips contained in the coating material of the present invention can be those that have the ability to correct the soil pH value, or those that are rich in plant fertilizer components such as phosphate, calcium, magnesium, potassium, copper, zinc, boron, etc., so that the waste hardened coating material also contains a large amount of the useful fertilizer component magnesium, etc. Therefore, the coating material and hardened waste of the present invention are expected to be useful materials that can be used as soil improvers and potting soil, which will greatly contribute to Japan's food production in the future. [Example]

[0029] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples as long as the gist of the present invention is not changed.

[0030] 1-1. Macronutrient properties of waste roof tile chips as plant nutrition We attempted to investigate the macronutrient content of waste roof tile chips, "Tecora (registered trademark), fine powder, particle size 1 mm or less," as plant nutrition. Figure 1 shows a photograph of the waste roof tile chips used, and Table 1 shows the physicochemical properties of the waste roof tile chips.

[0031] [Table 1]

[0032] As shown in Table 1, the content of macronutrients in plant nutrients was investigated, and the following results were obtained. (1) The pH value was slightly alkaline, suggesting that this material could be used to improve the soil pH value. (2) The amount of available phosphorus was somewhat lower than that of Japanese Kuroboku soils in upland fields, which suggests that the soil has the ability to supply phosphorus. (3) The amount of exchangeable calcium was also somewhat higher than that of upland soil, suggesting that agricultural soil has the ability to supply calcium. (4) The amount of exchangeable magnesium was also somewhat lower than that of upland soil, which suggests that the soil has the ability to supply magnesium as well as phosphate. (5) The amount of exchangeable potassium was somewhat lower than that of upland soil. It was presumed that the soil had the ability to supply exchangeable potassium to agricultural land, similar to phosphorus and magnesium. (6) The bulk density was heavier than that of normal soil, and the soil was classified as sandy loam.

[0033] The above results suggest that the evaluated waste roofing tile chips can be used as a material for correcting the soil pH value, and also as a material for supplying macronutrients such as phosphate, calcium, magnesium, and potassium. Furthermore, the fine powdered waste roof tile chips that were evaluated were classified as sandy loam in the soil classification. This strongly suggests that waste wall plaster can be used as an improvement material for agricultural land.

[0034] 1-2. Trace element characteristics of waste roof tile chips as plant nutrition We attempted to investigate the trace element content of plant nutrients using "Tecora (registered trademark), fine powder, particle size 1 mm or less" as waste roof tile chips. Table 2 shows the physicochemical properties of the waste roof tile chips.

[0035] [Table 2]

[0036] As shown in Table 2, the trace element content as plant nutrition was investigated, and the following results were obtained. (1) The amount of available copper was shown to be significantly higher than that of healthy soil in Japan. Therefore, it was estimated that the waste roofing tile chips evaluated could function as a supply material for soluble copper deficient soil. (2) The amount of available zinc was within the appropriate range compared to healthy soil in Japan. Therefore, it was estimated that the waste roofing tile chips evaluated function as a supply material of soluble zinc. (3) The amount of easily reducible manganese was significantly lower than that of healthy soils in Japan, unlike the results for soluble copper and soluble zinc. Therefore, the evaluated waste roofing tile chips were not recognized as a source of easily reducible manganese. (4) The amount of hydrothermally available boron was significantly higher than that of healthy soil in Japan. Therefore, the evaluated waste roofing tile chips functioned as a source of soluble zinc.

[0037] These results suggest that the evaluated waste roof tile chips can be used as a source of trace elements such as soluble copper, soluble zinc, and soluble boron. This fact strongly suggests that waste wall plaster can be used as an improvement material for agricultural land.

[0038] 2. Impact resistance of coating material Impact resistance was evaluated assuming that the coating material of the present invention was applied to the surface of an earthen wall used for the interior and exterior of a building. Earthen walls do not bear the structural force of a building. Therefore, rather than using a method to determine quantitative values ​​like concrete or mortar, a method was chosen to measure the resistance to breakage when hit by something.

[0039] Evaluation method Measuring equipment [diameter 51mm] JISA6909 (architectural finishing coating material). The impact resistance test panel uses a flexible board measuring 300 mm in length, 150 mm in width, and 6 mm in thickness. The test was carried out using a spherical weight W2-500 [mass 533g, diameter 51mm], and the top surface of the test piece It is performed by free falling from 30 cm. The weight mentioned above is dropped onto the impact resistance test plate. The evaluation is carried out by visually observing the condition of the test plate, such as 1) cracks, 2) peeling, and 3) deformation. Visual observation is the standard for JIS certification.

[0040] ·test A coating material was prepared by mixing waste roof tile chips (Tecora (registered trademark), fine powder) and magnesia cement with water. The ratio was 87% waste roof tile chips and 13% magnesium oxide. 260g of water was used per 1kg of the mixture. This was then applied to the surface of the test panel. The coating material (6 mm thick) was tested at an age of 7 days, when it was in the early stages of solidification, and at an age of 28 days, when it had stabilized. The test was carried out in duplicate. The results are summarized in Table 3. Figure 2 shows a photograph of the test specimen coated with the coating material at 7 days old, and Figure 3 shows a photograph of the test specimen coated with the coating material at 28 days old.

[0041] [Table 3]

[0042] -Time-specific fluctuations The results for the initial stage of solidification, at ages 7 and 28 days, showed that no (1) cracks, (2) peeling, or (3) significant deformation was observed at either age. These results demonstrate that the coating material of the present invention hardens extremely quickly. The coating material of the present invention can shorten the construction period, which is expected to be a major economic advantage.

[0043] -Variation in measurement values The results of the two series of measurements for both ages showed no differences in terms of (1) cracks, (2) peeling, or (3) significant deformation, as well as variations with time. This result suggests that the coating material of the present invention is mixed extremely uniformly and can be applied uniformly with minimal unevenness.

[0044] ·Conclusion The results of measurements taken at 7 days, when the paint was initially applied, and at 28 days, when the paint had solidified, as well as two consecutive measurements at both ages, showed no differences in (1) cracks, (2) peeling, or (3) significant deformation. In conclusion, it was shown that the coating material of the present invention solidifies extremely quickly, is mixed extremely uniformly, and can be applied uniformly with minimal coating unevenness.

[0045] 3. Antibacterial properties of coating materials The antibacterial activity of the coating material of the present invention was tested using the JAS Z 2801 film adhesion method. The pathogen used was Escherichia coli (NBRC 3972).

[0046] Characteristics of E. coli used in antibacterial activity tests E. coli is a pathogenic bacterium that is commonly found in our living environment and is easy to handle. E. coli is a gram-negative bacterium. Gram-negative bacteria tend to be more susceptible to inorganic chemicals. In general, when testing unprocessed products, E. coli tends to grow more easily.

[0047] Experimental method 1) Drop 0.4 ml of E. coli liquid onto a test piece (5 cm x 5 cm) in a petri dish, cover it with a film (4 cm x 4 cm), and then close the petri dish lid. The test is performed on unprocessed samples and coated samples. 2) Incubate the petri dish at 35°C and 90% RH or higher for 24 hours. 3) After 24 hours, add 10 ml of SCDLP medium and wash out the test bacteria from the polyethylene film and test specimen. 4) The number of bacteria in the washout solution is measured using the agar plate culture method. 5) Calculate the antibacterial activity value according to the following formula. Antibacterial activity value = log 1cm of untreated sample 2 Number of live bacteria per 1cm of processed sample after incubation - log 2Number of live bacteria per 100ml after incubation 6) Polyethylene film was used for the processed test specimens. This is because JIS certification stipulates the use of polyethylene film for unprocessed products. Figure 4 is a schematic diagram of the coating material sample used in the test. Using a coating material with the same composition as in the impact resistance evaluation, a sample with the shape shown in Figure 4 was prepared and evaluated.

[0048] Antibacterial activity (effectiveness) evaluation method The antibacterial activity (effectiveness) evaluation method is expressed as "common logarithm of the number of viable bacteria in the unprocessed product after cultivation" minus "common logarithm of the number of viable bacteria in the processed product after cultivation." If there is a difference of 2.0 or more between the two values, it is recognized as a significant difference according to the JIS.

[0049] Antibacterial activity against E. coli Tables 4 to 6 show the results of the antibacterial activity against Escherichia coli.

[0050] [Table 4]

[0051] [Table 5]

[0052] [Table 6]

[0053] The common logarithm value of the antibacterial effect of E. coli (unprocessed test paper) was 4.14, and the common logarithm value after 24 hours was 5.93. The value of the unprocessed product is what is growing. The antibacterial activity value of the coating material was 6.1, which was three times the effective activity value. Therefore, it was clear that the coating material had clear antibacterial activity against E. coli. Since E. coli originates from human feces, livestock feces, and the feces of birds, pet birds, dogs, cats, etc., it is the most common pathogen in the human living environment. The fact that the coating material of the present invention has a high bactericidal effect on E. coli was an extremely useful result. In conclusion, the results have revealed that the coating material of the present invention has an extremely strong antibacterial effect against Escherichia coli.

[0054] 4. Moisture absorption test The moisture absorption performance of the coating material of the present invention was investigated. Test specimens (100 mm square) made using the same coating material formulation as used in the impact resistance evaluation were equilibrated in a thermo-hygrostat chamber at 25°C and 50% RH. The test specimens were then placed in the thermo-hygrostat chamber at 25°C and 90% RH, and the amount of moisture absorption was measured over 24 hours. They were then placed in the thermo-hygrostat chamber at 25°C and 50% RH, and the amount of moisture release was measured. Observation of the moisture absorption and release processes of the test specimens under different humidity conditions confirmed their moisture absorption and release properties.

[0055] To sum up the above research results, the coating material of the present invention and the coating using this material made the wall plaster strong and had high impact resistance and disinfecting properties against pathogens (E. coli).

[0056] Furthermore, the coating material of the present invention and the coating using the same have moisture absorption and release properties. Therefore, the wall plaster coated with the coating material of the present invention can be used as a material with a humidity control function. [Industrial Applicability]

[0057] The coating material of the present invention can be used to coat structures such as mud walls and is therefore industrially useful.

Claims

1. A coating material containing roof tile chips and magnesia cement.

2. The coating material according to claim 1, wherein the magnesia cement is 5 to 30 parts by mass per 100 parts by mass of the roof tile chips.

3. A structure having a surface coated with the coating material according to claim 1 or 2.

4. A structure having an earthen wall coated with the coating material according to claim 1 or 2.

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