JPS6261551B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to steam-cured lightweight cellular concrete (hereinafter abbreviated as ALC) with excellent impact resistance. ALC is made by pulverizing silica raw materials such as silica sand and silica stone, and calcareous raw materials such as lime and cement, mixing water in an appropriate ratio, and adding a foaming agent such as aluminum metal powder to form a slurry. Either the slurry is poured into a mold with reinforcing bars installed in advance and foamed, or the slurry is poured into the mold and foamed, then reinforcing bars are incorporated and the semi-plastic state is transferred to an autoclave where it is heated at high temperature and pressure. Manufactured using steam curing. ALC manufactured in this way has a large number of pores, making it lighter than water, but it is said to be prone to chipping due to shocks and local concentrated loads during the manufacturing process, product transportation, or construction. There are drawbacks. In order to prevent these ALCs used as building materials from chipping, a method has conventionally been proposed in which a fibrous material such as glass fiber is bonded to the surface layer of the ALC using a synthetic resin binder for reinforcement. However, although it is true that impact resistance can be improved by reinforcing these fiber materials, the effect is not expected because the reinforcing material is only fixed to the surface layer. At present, it is not possible to obtain as much impact resistance as possible, and there is a strong desire for something with even better impact resistance. In order to obtain ALC with improved impact resistance and without the drawbacks of conventional products, the inventor of the present application first developed a heat-resistant aromatic polyamide fiber, which is made by binding monofilaments of 10 denier or less into 20 to 15,000 denier fibers. He invented a product mixed into raw material slurry and applied for a patent (Japanese Patent Application 179339-1983). An object of the present invention is to provide a product that is further improved from the above-mentioned ALC product. In order to achieve this object, the present invention incorporates monofilaments of 20 denier or less into the raw material composition of ALC, either as single fibers or after bundling, and adding one or more of synthetic resins, latex, asphalt, cellulose, or inorganic fibers with these. A heat-resistant aromatic polyamide fiber whose surface is treated with a mixture with an adhesive so that the adhesion amount is 1 to 200 parts by weight per 1 part by weight of the fiber, and the length is 100 mm or less, preferably 3 mm or more.
ALC with excellent impact resistance is obtained by adding and mixing 0.1 to 3.0% by weight of the solid material of the raw material mixture and then autoclaving it according to a conventional method.
That is. That is, the ALC of the present invention uses synthetic resin, latex, asphalt, cellulose, or a mixture of these and an inorganic adhesive after or before bundling the monofilaments of aromatic heat-resistant fibers. It is novel in that it is applied in an amount of 1 to 200 parts by weight per 1 part by weight of the fibers, coated, and then mixed into the main raw material slurry. In this case, the latter is bonded with a synthetic resin or the like and then bundled to a predetermined denier. The direct purpose of surface-treating the above fibers with synthetic resin etc. is to prevent the mechanical strength from decreasing due to the influence of strong alkaline substances from the raw material mixture under high temperature and high pressure conditions during ALC production of the fibers to be mixed. fiber and
The aim is to improve the adhesion of ALC, and it is thought that the impact resistance of ALC will improve as a result. The outline of the present invention will be explained below. In addition to the aromatic polyamide heat-resistant fiber used in the present invention, various types of fibers may be used to mix in the production of ALC. For example, asbestos fibers, glass fibers, alkali-resistant glass fibers, nylon, polyester fibers, etc., but fibers such as asbestos fibers, which have strong "stiffness" and strong water absorption, are used in the foaming process of ALC production. Formation of spherical bubbles is inhibited, resulting in a decrease in strength and impact resistance.Alkali-resistant glass fibers are not as stiff as asbestos fibers, but are highly flexible and can provide good foaming properties. , they are eluted into alkaline water during the autoclave curing process, and nylon and polyester fibers have fatal disadvantages such as melting during the autoclave curing process due to their lack of heat resistance, and both of these are undesirable. Therefore, the fibers used in the production of ALC of the present invention are specified as heat-resistant aromatic polyamide fibers. The heat resistance of this fiber includes retention of fiber performance at high temperatures, dimensional stability, and retention of fiber performance even after exposure to a high temperature atmosphere of 180℃.
It is necessary that the load-extension curve in the above condition hardly changes from the normal temperature state. The aromatic polyamide-based heat-resistant fibers include Konex (trade name, manufactured by Teijin) and Kevlar.
29 Aramid (trade name, manufactured by DuPont), linear aromatic polyamide fibers, such as polyparabenzamide, etc. can be used. Next, surface treatment agents for the fibers include synthetic resins such as epoxy, melamine, phenol, urea, alkyd, unsaturated polyester, α-olefin, vinyl urethane, polyurethane, polystyrene,
Vinyl acetate, ethylene vinyl acetate, acrylic vinyl acetate, acrylic, cyanoacrylate,
Various resins such as silicone, latex include chloroprene, nitrile rubber, styrene-butadiene latex, natural latex, etc. Asphalt includes natural asphalt, straight asphalt made from petroleum, blown asphalt, etc. Cellulose includes methyl cellulose, ethyl cellulose, cyanoethyl cellulose, benzyl cellulose, hydroxy methylcellulose, etc. Next, examples of inorganic adhesives that can be used in combination with the above resins include common inorganic adhesives such as cement, aluminum phosphate, sodium silicate, silica sol, alumina sol, and lithium silicate, or mixtures thereof. It is. In addition, fillers that are commonly added to paints, such as talc, calcium carbonate, and silica powder, can also be added for modification. Next, as a method for surface treatment of the fibers, one or more of the above-mentioned synthetic resins, latex, asphalt, and cellulose, or a mixture of these and an appropriate amount of inorganic adhesive, is mixed with an appropriate amount of organic solvent or water. Dissolved or emulsionized, or used as is without dilution as the case may be, coated the fiber with a predetermined amount by dipping, spraying, or coating, and then air-drying. ,
In some cases, common methods of heat treatment can be applied. Monofilaments are bundled using a very small amount of binding agent such as synthetic resin or by twisting. The reason for attaching 1 to 200 parts by weight of a synthetic resin, etc. to 1 part by weight of aromatic polyamide fibers after or before bundling the monofilaments is to prevent the adhesion of the above-mentioned fibers and ALC. This is because the strength and mechanical strength of the fibers are low and no significant effect on impact resistance is observed, and no particular improvement in the effect is observed even if the fibers are adhered further. The reason why the monofilament is 20 denier or less is because it is difficult to manufacture monofilaments larger than 20 denier. The reason why the bundled fibers are set to be less than 15,000 denier is because if it exceeds this value, the bundled fibers will lose their flexibility, and excessive stress will be applied during foaming, inhibiting foaming and preventing the formation of good bubbles. can be,
The reason why the length of the fibers and the amount of added fibers are specified above is that if the length of the fibers is 100 mm or more or the amount added is 3.0% by weight or more, the added fibers will become entangled with each other and form a "protective" shape. This is because it is difficult to disperse uniformly, causing internal defects and reducing mechanical strength.
This is because if the amount is less than % by weight, the impact resistance effect will not be noticeable. Limestone raw materials, which are a mixture of the main raw materials for ALC, include lime, cement, etc., silica raw materials include silica stone, silica sand, blast furnace slag, fly ash, etc., and foaming agents include aluminum powder, surfactants, etc.
The reinforcing bars are not particularly limited as long as they are commonly used materials such as welded mats, laths, wire meshes, etc. made of iron, aluminum, stainless steel, etc. In addition, stirring of raw material mixtures can be done using paddle type mixers, propeller type mixers, turbo type mixers, grid type mixers, etc.
A commonly used stirrer such as a pot mixer can be used. In order to uniformly disperse the aromatic polyamide heat-resistant fibers, the fibers may be treated with a surfactant in advance, or a surfactant may be added to the raw material slurry as necessary. Steam curing in an autoclave after foam molding can be carried out under general conditions, for example, using saturated steam at a gauge pressure of 10 Kg/cm ² and a temperature of 180°C. Examples will be described below. Example 1 6 parts by weight of quicklime powder, 22 parts by weight of Portland cement, 32 parts by weight of silica powder, 0.05 parts by weight of aluminum powder, 40 parts by weight of water, and aromatic polyamide based on the total amount of the solids. After tying 1.5-denier monofilament heat-resistant fibers of the same type into a predetermined size using the twisting method, the fibers were immersed in an emulsion of styrene-butadiene latex with an appropriate amount of water, and its adhesion was confirmed. The fibers were pulled, air-dried, and heat-treated in an amount of 0.5 to 250 parts by weight per 1 part by weight of the fibers, and then added to the above slurry at a predetermined ratio and mixed, followed by a specific gravity of 0.5 according to normal operations. ALC was produced. A test piece measuring 10 x 15 x 3 cm was cut from the obtained product and subjected to an impact test. Impact resistance test method A test piece was fixed horizontally with a fulcrum spacing of 10 cm, and a 300 g eggplant-shaped steel ball was dropped onto the center of the test piece from a height of 13 cm. This was repeated until a crack appeared on the test piece, and the number of drops was measured. Therefore, the greater the number of drops, the better the impact resistance. In addition, regarding the quality of the bubbles, when the bubbles were observed under a microscope and were non-uniform and there were few closed cells, it was expressed as "failure". In addition, as a comparative example, the same tests were carried out using fibers to which heat-resistant fibers were not subjected to surface treatment (coating), or to which the fibers were not added at all. The results are shown in Table 1. Kevlar 29 aramid (registered trade name, manufactured by DuPont) was used as the aromatic polyamide heat-resistant fiber.

【table】

[Table] From the results in Table 1, the length of the heat-resistant fiber is ~100mm
In the test examples in which the addition rate was 0.1 to 3.0% by weight, the impact resistance was better and the cell condition was better than in Test No. 1, in which no fiber was added. Heat-resistant fibers that have been surface-treated with latex or the like, with an adhesion amount of 1 to 200 parts by weight per 1 part by weight of the fibers, have much improved impact resistance than when untreated fibers are used. was gotten. Test Nos. 2, 3, and 8, which were outside the scope of the products of the present invention.
Test Nos. 9, 16, 17, 32, and 33 had poor impact resistance, and test Nos. 16, 17, 32, and 33 had poor bubble formation, respectively. Example 2 In Example 1, a 10-denier monofilament of Cornex (trade name, manufactured by Teijin) was used as the heat-resistant fiber, and a phenol resin dissolved in a small amount of alcohol was used as the surface treatment agent. After attaching 25 parts by weight to each part by weight, they are bundled into 500 denier, 3000 denier, and 13000 denier (fiber lengths are 10 mm, 30 mm, and 100 denier, respectively).
The test results when (mm) are similar to Table 1,
In all cases, sufficiently satisfactory results in impact resistance were obtained. Example 3 In Example 2, a mixture of 150 parts by weight of ordinary Portland cement and 10 parts by weight of natural latex emulsion was used as a surface treatment agent, 39 parts by weight of water was added and the mixture was thoroughly stirred.
The test results obtained when 100, 150, and 200 parts by weight of this coating were applied to 1 part by weight of fiber were similar to those shown in Table 1, and in all cases, sufficiently satisfactory results in impact resistance were obtained.

Claims (1)

[Claims] 1. In steam-cured lightweight cellular concrete that uses powdered siliceous raw materials and calcareous raw materials as main raw materials and has built-in reinforcing bars, 20%
Monofilaments of denier or less, either as single fibers or after being bundled, are coated with one or more of synthetic resin, latex, asphalt, cellulose, or a mixture of these and an inorganic adhesive, so that the amount of adhesion reaches 1 fiber.
Aromatic polyamide heat-resistant fibers with a length of 100 mm or less, surface-treated to be 1 to 200 parts by weight and bundled to 15,000 denier or less, 0.1 to 3.0 parts by weight to the solid material of the main raw material. % steam-cured lightweight cellular concrete with excellent impact resistance.