JPH0524012A - Manufacture of hydraulic inorganic molded product - Google Patents

Abstract

PURPOSE:To provide the manufacturing method of hydraulic inorganic molded product, which can be formed without impairing its fluidity, has high strength and is excellent in durability even when a material prepared by adding fine particles to composition prepared by adding water, the amount of which is as equal to the amount required stoichiometrically as possible, to the hydraulic inorganic substance is dealt with. CONSTITUTION:Composition consisting of 100 pts.wt. of hydraulic inorganic substance, 2-100 pts. wt. of fine inorganic filler having the particle side of 10mum or less and 15-40 pts.wt. of water is mixed and pressed under vibration.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a hydraulic inorganic molding having high strength and excellent durability.

[0002]

2. Description of the Related Art Molded articles using a hydraulic inorganic substance such as cement, mortar or gypsum have been used for various structural materials since ancient times. In the process of producing these hydraulic inorganic substance molded bodies, the hydraulic inorganic substance and water are uniformly kneaded, and in order to ensure good fluidity, water of a stoichiometric amount or more in the hydration reaction of cement is used. Has been added. Therefore, there is a problem that voids due to excess water are formed in the molded product after curing, and strength, durability, etc. are reduced as compared with a molded product cured with an amount of water close to stoichiometry.

Therefore, in order to obtain a high-strength hydraulic inorganic molding, as described in JP-A-2-160650, silica sand having a brain value of 3,000 cc / g or more (average particle size is 5 to 10 microns or less, but there is no exact correspondence because it differs in shape.) Composition in which water is added in an amount as close as possible to the stoichiometry of 20 to 35 parts by weight to 100 parts by weight of cement mixed. There is disclosed a method of filling the above voids with fine particles, such as molding a high-strength lightweight roof tile by extrusion molding using a material.

[0004]

However, in the production method described in JP-A-2-160650, water is adsorbed by the fine particles because the water-cement ratio is small and the specific surface area of the fine particles is very large. However, there is a problem that the fluidity of the composition is extremely poor and that only a molded product having a simple shape such as a flat plate as described in the above publication can be shaped, and cannot be applied to a molded product having a complicated shape. Further, in order to form by press molding using the kneaded product described in the same publication, it is necessary to perform the molding under an extremely high pressure, and since the kneaded product has low fluidity, a large-sized molded product can be obtained. Was extremely difficult.

The object of the present invention is to solve the above problems and to provide a composition in which fine particles are added to a composition in which water is added to a hydraulic inorganic substance in an amount as close to stoichiometry as possible. It is an object of the present invention to provide a method for producing a hydraulic inorganic molded product that can be molded without impairing fluidity, has high strength and is excellent in durability.

[0006]

The hydraulic inorganic substance used in the present invention is not particularly limited as long as it is an inorganic substance which shows a hardening property when kneaded with water. For example, ordinary Portland cement, special Portland cement, alumina cement, Examples include plain cements such as Roman cement, acid-resistant cements, fire-resistant cements, special cements such as water glass cements, and air-hardening cements such as gypsum, lime, and magnesia cements. Particularly, in terms of strength and water resistance, Portland cement and alumina cement are preferably used. The amount of water used in the production method of the present invention,
If the amount is less than 15 parts by weight with respect to 100 parts by weight of the hydraulic inorganic substance, the hydraulic inorganic substance is not sufficiently cured, and the dispersability of the reinforcing fibers and the inorganic filler decreases, and the amount is more than 40 parts by weight. Since the mechanical strength of the molded body decreases, 15
It is limited to 40 parts by weight, preferably 20 to 35 parts by weight.

The fine inorganic filler used in the present invention is not particularly limited as long as it does not dissolve in water and does not inhibit the hardening reaction of the hydraulic inorganic substance. For example, aggregate for cement mortar such as silica sand and river sand, Mixtures for mixed cement such as fly ash, silica flour, silica fume, bentonite, blast furnace slag, and natural minerals such as sepiolite, wollastonite, calcium carbonate, and mica. These may be used alone or in combination of two or more kinds.

The fine inorganic filler has an average particle size of 10
If it is more than μm, it becomes difficult to disperse the fine inorganic filler in the voids of the hydraulic inorganic substance molded body, and the mechanical strength and durability of the molded body are reduced, so that it is limited to 10 μm or less,
If it is less than 0.03 μm, the effect of filling the voids of the hydraulic inorganic substance molded body is not improved any more, and only the difficulty in production is raised, and it is necessary to impart fluidity capable of molding. 0.03 to 5 μm is preferable because the amount of water increases and the effect of improving mechanical strength is not observed.

If the amount of the finely divided inorganic filler added is less than 2 parts by weight, the effect of filling the voids is not observed, so that the mechanical strength is not improved, and if it exceeds 100 parts by weight, the voids of the molded article are not formed. The filling effect is not further improved, but the molding pressure is increased, the amount of water required for imparting moldable fluidity is increased, and the mechanical strength of the molded article is rather reduced. It is limited to parts by weight, preferably 5 to 50 parts by weight.

In the present invention, an inorganic filler having a particle size of more than 10 μm may be added if necessary. The same inorganic filler as that used in the fine inorganic filler is used. When the addition amount of the above-mentioned inorganic filler exceeds 200 parts by weight, the mechanical strength of the molded article decreases, so 200 parts by weight or less is preferable.

In the present invention, a water-soluble polymer substance may be added if necessary. The water-soluble polymer substance,
It dissolves in water to give viscosity, enhances the dispersibility of inorganic fillers and reinforcing fibers, enhances the fluidity of the mixture to improve shapeability, and absorbs excess water in the hardened cement. There is no particular limitation as long as it is a polymeric substance that can serve as a binder that fills the voids between the cement particles. For example, methylcellulose, hydroxymethylcellulose, hydroxyethylcellulose, carboxymethylcellulose, hydroxypropylmethylcellulose. Examples thereof include cellulose ethers such as cellulose, polyvinyl alcohol, and polyacrylic acid. When the amount of the water-soluble polymer substance added exceeds 5 parts by weight, the water resistance of the obtained molded article decreases, so 5 parts by weight or less is preferable.

In the present invention, reinforcing fibers may be further added if necessary. As the reinforcing fiber, any fiber can be used according to the performance to be imparted to the molded product, and for example, synthetic fiber such as vinylon, polyamide, polyester, polypropylene or the like, or glass fiber can be used. In particular, when synthetic fibers are used, it is possible to impart flexibility that cannot be obtained by conventional hydraulic inorganic molded articles. Further, if the thickness of the reinforcing fiber is too thin, it reaggregates during mixing, fiber fibers are likely to be formed due to entanglement, and the strength of the obtained molded body is not further improved. If it is too large, the reinforcing effect such as improvement in tensile strength is small, and if it is too long, the dispersibility and orientation of the fibers are deteriorated. Therefore, the thickness is preferably 1 to 40 denier and the length is 3 to 15 mm. When the amount of the reinforcing fiber added exceeds 20 parts by weight, the fiber ball is formed by the entanglement of the fibers, and the strength of the obtained molded article decreases, so 20 parts by weight or less is preferable.

The method for producing a hydraulic inorganic molded body of the present invention is characterized in that the composition comprising the hydraulic inorganic substance, the fine inorganic filler and water is mixed and vibration-pressed. As the mixing method, any conventionally known method is used.

In the above-mentioned vibration pressure molding, the composition obtained by the production method of the present invention is supplied into a pressure mold having a desired product shape, and pressure molding is performed while vibrating the mold.

The pressing die used in the present invention is a conventionally known pressing die to which a conventionally known vibrator is attached. The pressing die and the mixture supplied into the pressing die are three-dimensionally oriented. In order to give a slight vibration, and to give thixotropic properties to the kneaded product effectively, it is preferable to give the pressing die a frequency of 100 to 10,000 Hz with an amplitude of 1 to 500 μm. For such a molding method, for example, a vibration press molding machine as described in the Aichi Tokoname Ceramics Technology Center-Research Results Report in 1988 can be used.

The hydraulic inorganic molded body obtained by the production method of the present invention is heated during molding, for example, during press molding, if a hydraulic inorganic material having a high curing rate such as gypsum is used. Therefore, it can be cured at the same time as molding, and the molded body obtained may be naturally cured over time, but a hydraulic inorganic substance such as Portland cement, which has a slow curing reaction, is used. In this case, it goes without saying that the curing reaction can be promoted and the mechanical properties can be improved by carrying out curing by a conventionally known method such as heating and humidifying the molded body.

[0017]

EXAMPLES The details of the present invention will be described in more detail with reference to Examples. Examples 1 to 5 and Comparative Example 1 A predetermined amount of ordinary Portland cement shown in Table 1, a silica particle having a maximum particle size of 10 μm or less and an average particle size of 0.1 μm.
Fine particles of silica having a maximum particle size of 10 μm or less and an average particle size of 3 μm, wollastonite (Tsuchiya Kaolin Co., Ltd., trade name: Chemolit A-60), 2 denier thick, 6 mm long vinylon fiber, hydroxypropyl Methyl cellulose (2
A 2% aqueous solution having a viscosity of 30,000 cps at 0 ° C.) was placed in a 10-liter mixer (trade name; Eich-Mixer RV02 manufactured by Erich Co.) and mixed for about 3 minutes, and a predetermined amount of water was added. And mixed for another 2 minutes. The obtained mixture was molded with a vibration press molding machine (Asahi Engineering Co., Ltd., trade name; SA-50) at a predetermined pressure at a frequency of 1,000 Hz and an amplitude of about 10 μ, and a rib having a depth of 20 mm and a width of 15 mm was formed. 5 with 2
A plate-shaped molded body of 00 mm × 500 mm × 6 mm was obtained.

Comparative Example 2 A composition having a predetermined amount of the compound shown in Table 1 was obtained in the same manner as in Example 1 and molded with a press molding machine at a predetermined pressure to obtain a plate-shaped molded body.

Comparative Example 3 A composition having a predetermined amount shown in Table 1 was mixed in the same manner as in Example 1, kneaded in a clay kneader, and extruded at a predetermined pressure in a vacuum extruder to form a plate. A shaped body was obtained.

As described above, the obtained Examples 1 to 10 and Comparative Example 1
The molded bodies of Nos. 3 to 3 were aged at 60 ° C. and 90% RH for 6 hours, the flat plate portion was cut to obtain a test piece, and the test piece was subjected to the following tests. The above results are also shown in Table 1.

[0021]

[Table 1]

Evaluation of Physical Properties Complex Moldability Whether or not the rib shape was formed was visually judged, and a mark of “formed” and a mark of “×” were given for those not formed. Bending Strength The bending strength of the obtained molded body was measured according to the method of JIS A 1408. Freeze-thaw property The obtained molded article was subjected to a freeze-thaw test according to the method of ASTM C 666A, and the number of cycles in which cracking occurred was shown.

[0023]

The method for producing a hydraulic inorganic molded article of the present invention is a method in which a hydraulic inorganic material is mixed with a specific amount of a fine inorganic filler having a particle diameter of 10 μ or less and a composition comprising water, and then vibration pressing is performed. Since the press molding is performed while giving a three-dimensional slight vibration to the pressing die, sufficient fluidity can be imparted to the above composition, and thus voids due to excess water formed in the molded product after curing are minute. Since it is filled with particles, it is possible to cure the hydraulic inorganic substance with an amount of water close to stoichiometry.
Further, it is possible to perform molding with a pressure of 1/5 to 1/20 as compared with the conventional press molding, and it is possible to mold even a complicated shape as compared with the conventional molding method.

Therefore, according to the method for producing a hydraulic inorganic molded product of the present invention, it is possible to manufacture molded products having various shapes having high strength and excellent durability.

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Claims (1)

Claims: 1. Hydrophilic inorganic substance 100 parts by weight, particle size 10
2 to 100 parts by weight of fine inorganic filler having a size of μ or less, and water 1
A method for producing a hydraulic inorganic molded body, which comprises mixing a composition containing 5 to 40 parts by weight and subjecting it to vibration pressure molding.