JPH0580423B2 - - Google Patents

Description

[Detailed description of the invention]

``Object of the Invention'' The present invention relates to a hydraulic compound composition, which has excellent bending strength in the formed coating layer, etc., effectively prevents cracking, and which can be applied with excellent workability. The aim is to provide a hard compounding composition at a relatively low cost. Industrial fields of use Hydraulic compound compositions used in various molded objects, top coating materials, spray materials, etc. BACKGROUND ART Conventionally, preparation of a kneaded material using powder of a hydraulic substance such as cement or gypsum has been widely practiced. Further, in order to strengthen the bending strength of the molded product made from such a kneaded product, and in particular to avoid the occurrence of cracks, various studies have been conducted on blending various fiber materials, and in recent years, pitch-based carbon fibers have also been developed. The compounding of this product was also studied, and such technology was announced in JP-A-56-73663, JP-A-58-69756, and JP-A-59-33105. Problems to be Solved by the Invention However, it is difficult to add and mix the above-mentioned carbon fibers and the like into the above-mentioned hydraulic kneaded material and mix them uniformly, that is, the carbon fibers are unevenly distributed, making it difficult to achieve the desired dispersion mixing. Since this carbon fiber is difficult to obtain and is expensive, it is necessary to add as little amount as possible. Difficult to obtain effect. For example, in cases where mortar prepared into a kneaded material in this manner is used as an overcoat layer, cracking due to drying shrinkage cannot be effectively prevented even though fine fibers are added and mixed, and the workability is affected. However, it has been confirmed that problems remain, such as elongation during troweling, sagging from the applied surface, adhesion, and bending strength. "Structure of the Invention" Means for Solving the Problems A hydraulic substance powder containing carbon fibers in an amount of 0.05 to 2 wt% of the powder, methylcellulose, sodium alkylsulfonate, polycarboxylic acid, sodium ligninsulfonate, etc. A hydraulic compound composition characterized in that one or more water reducing agents are mixed and water is added and kneaded. Function Water reducing agents such as methyl cellulose and sodium alkyl sulfonate are effective in improving the bending strength of the resulting kneaded product. Furthermore, by blending these methyl celluloses with a water reducing agent, the dispersibility of a relatively small amount of carbon fiber in the kneaded material is improved, and the carbon fibers are uniformly dispersed. Therefore, the properties such as bending strength, adhesion strength, and water absorption properties of products and coating layers obtained by using the kneaded product are improved, and the occurrence of cracks after drying is greatly reduced. Addition amount of carbon fiber to hydraulic material powder is 0.05
By setting the amount to 2 wt%, the amount of expensive carbon fiber used can be reduced, and a hydraulic compound composition having the above-mentioned properties can be provided at a low cost. EXAMPLES To further explain the present invention as described above, the present inventors have conducted detailed research on adding and mixing the above-mentioned pitch-based carbon fibers to mortar and paste, which are representative examples of the above-mentioned hydraulic kneaded products. As a result of repeated efforts, as mentioned above, the main reason why desirable properties such as prevention of crack generation cannot be effectively obtained is that the fibers are not evenly dispersed in the kneaded material, especially when the content is as small as 2% or less. It was confirmed that this was due to some difficulty. Therefore, as a result of further studies on how to stably form a preferable uniform dispersion state of carbon fibers in commonly prepared mortar, etc., we found that it is preferable to add and mix carbon fibers together with methyl cellulose and a water reducing agent. I found out. As mentioned above, lime silicate or gypsum hemihydrate is used as the hydraulic substance powder, and when used as mortar, sand, perlite, pumice sand, shirasu balloon, etc. can be used. The amount of carbon fiber mixed in this material is 0.05 to 2% by weight based on the hydraulic powder, and if it is less than 0.05%, it is too small and almost no entanglement of the carefully added carbon fibers can be obtained. Since it is not present, the effect of addition cannot be determined. On the other hand, if it is added in an amount exceeding 2% to the hydraulic powder, the kneaded material will become lumpy and the stability of construction will be lacking. The carbon fiber preferably has a thickness of 5 to 30 x 10 ^-3 mm and a length of 3 to 10 mm. The appropriate amount of methyl cellulose to be added is 0.05 to 0.17 wt% based on the hydraulic powder, and along with methyl cellulose, water reducing agents such as sodium alkylnaphthalene sulfonate, polycarboxylic acid, and sodium lignin sulfonate may be added. The amount is calculated in terms of solids for hydraulic powder.
By adding methyl cellulose and a water reducing agent together, it is possible to homogenize the dispersion of carbon fibers, which are relatively small at 2% or less, in the kneaded material, and to reduce carbon fibers at 0.05% or more. An appropriate intertwined state can be formed. Therefore, it effectively prevents cracking when used as a topcoat, reduces rebound during spraying, provides a good trowel finish, and improves proper kneading properties such as separation, adhesion, and tackiness. get something. The product according to the present invention further improves the above-mentioned properties by adding calcined soybean, anhydrite powder, and a formite mineral crushed in a liquid to the above-mentioned kneaded product, and Further advantages can be obtained. Regarding the amount of these additions, the amount of calcined alum is 1 to 1 for hydraulic powder.
The amount of holmite minerals is approximately 4wt%, and the amount of holmite minerals is approximately 0.2 to 1.2wt% of the hydraulic powder.Details regarding the crushed material of such holmite minerals are described in Japanese Patent Application Laid-Open No. 1118751/1983. has been
It is preferable that the diameter is about 0.5 μm and the length is about 15 to 20 μm. That is, calcined alum and anhydrite promote the hardening of the kneaded material and also alleviate shrinkage after hardening, thereby contributing to avoidance of cracking and development of strength properties, or improve uniform dispersion of fine fibers. Further, those according to the present invention include acrylic, ethylene,
One or more types of vinyl acetate derivatives, latex emulsions, etc. can be added and mixed in an amount of 5 to 20% of the weight of the hydraulic powder in terms of solid content, and by adding and mixing such emulsions, waterproofness can be improved. Mortar with improved water absorption, adhesion, etc. can be obtained. Regarding specific kneading adjustments, it is clear that all the ingredients and water may be simply added and mixed, but it is recommended to thoroughly mix them in advance using a dry mixing method without adding water, and then add water and knead. is extremely effective for quality control. That is, such a dry blend can be put into a bag or other container as it is and commercialized, and it is sufficient to simply add water and mix it before use. In either case, it is preferable to sprinkle hydraulic powder on the carbon fiber surface before mixing other materials (cement, fine aggregate, water reducer, thickener, etc.). Other aggregates are similarly mixed under dry conditions. Furthermore, a portion of the amount of hydraulic powder such as cement required to prepare the kneaded material is mixed with carbon fibers to ensure sufficient adhesion, and this mixture is mixed with a portion of the amount of cement prepared on site. It can be added to a small amount of mortar to create the desired mortar. Its usage may be by forming an overcoat layer, by spraying, or by forming a molded article. Specific examples of preparation, use thereof, and comparative examples according to the present invention will be described below. Comparative examples of pastes specifically adopted by the present inventors, formulation examples of the present invention, and their performance test results are as shown in Table 1 below. The tensile test was measured in accordance with JISA1113, and the restraint crack test was conducted using a diameter 26
A specimen with a mm-thick collar attached was embedded in a test specimen made of paste or mortar and left in a 20°C, RH 60% environment, and the crack width and number of cracks were visually measured.

【table】

[Table] That is, the composition according to the present invention has the same compressive strength as the comparative example, but considerable improvements in property values such as bending strength, adhesion strength, and tensile strength are observed, and the cracking test results are also zero. It was confirmed that cracks can be accurately prevented. Comparative examples and blending examples of the present invention regarding mortars also using fine aggregate and their performance test results are shown in Table 2 below.

[Table] That is, according to the present invention, in this example in which fine aggregate was blended, in the case in which methyl cellulose and a water reducing agent were blended together with carbon fiber, in the case in which the same amount of carbon fiber was blended (Comparative Examples 2 and 3). It was confirmed that the bending strength was improved by around 30% or more, and the tensile strength and adhesive strength were also high, and the occurrence of cracks was sufficiently reduced, with no occurrence. . It is clear from Comparative Examples 2 and 3 that such results cannot be obtained even if only one of methylcellulose and a water reducing agent is added. It is clear that the water absorption properties of the products according to the present invention have been improved to a certain extent. "Effects of the Invention" According to the present invention as explained above, the dispersibility of this type of hydraulic compound kneaded material containing a relatively small amount of carbon fiber is appropriately improved, and the bending strength and other properties are appropriately improved. At the same time, the invention effectively prevents the occurrence of cracks and allows construction to be performed simply and at low cost, and is industrially highly effective.

Claims (1)

[Scope of Claims] 1. A hydraulic material powder containing carbon fibers in an amount of 0.05 to 2 wt% of the powder, and one or more of methylcellulose, sodium alkylsulfonate, polycarboxylic acid, sodium ligninsulfonate, etc. A hydraulic compound composition characterized in that a water reducing agent is mixed therein, and water is added and kneaded. 2. The hydraulic compound composition according to claim 1, in which sand and other fine aggregates are added and mixed.