JPH07156328A - Production of hydraulic inorganic laminate - Google Patents

Abstract

PURPOSE:To provide a method of producing a dense, hydraulic inorganic laminate which, despite a low fiber content, is excellent in flexural strength, impact resistance and freezing damage resistance. CONSTITUTION:In order to obtain a hydraulic inorganic laminate consisting of a plurality of layers containing different amounts of reinforcing fibers, a plurality of unhardened forming bodies obtained from the hydraulic inorganic compositions containing different amounts of reinforcing fibers are built up to the desired layer structure and such layers are pressed into shape while being vibrated in the layered condition.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing a hydraulic inorganic laminate.

[0002]

2. Description of the Related Art A cured product obtained by extruding or press-molding a hydraulic inorganic substance such as cement, mortar and gypsum and water and curing it has long been suitably used for various structural materials. These hydraulic inorganic cured products have a high compressive strength, but are inferior in bending strength and impact resistance, so that they are used by being reinforced with reinforcing fibers and the like (see Japanese Patent Publication No. 57-1909). However, even if a large amount of fibers are used to improve the strength, not only the cost becomes high, but also the dispersibility of the fibers is lowered, so that there is a drawback that the strength is rather lowered.

Therefore, a method for effectively utilizing fibers has been developed in order to produce a hydraulic inorganic molding having excellent bending strength and impact resistance. As such a method, for example, Japanese Patent Application Laid-Open No. 63-257631 proposes a method of producing a laminate to localize the reinforcing fibers in the thickness direction.

However, a problem when producing such a laminate is the adhesiveness at the laminate interface between the layers. That is, if the adhesion between the layers is poor, the effect of improving the bending strength due to the lamination is reduced, and the layers are easily peeled off, so that the frost damage resistance is significantly reduced. As a method for solving this drawback, for example, JP-A-55-1624
In Japanese Patent Laid-Open No. 7-76, since cracks are easily generated when the molded bodies are laminated and pressed, it is proposed to apply a water-soluble synthetic resin emulsion between layers to prevent the cracks.

However, it is difficult to obtain a dense molded product by the above-mentioned method, and it is not possible to expect a remarkable improvement in strength and frost damage resistance, and it is also disadvantageous in that it requires complicated equipment.

[0006]

In view of the above circumstances, the present invention provides a method for producing a dense hydraulic inorganic laminate which is excellent in bending strength, impact resistance and frost damage resistance with a small fiber content. It is an object.

[0007]

In order to achieve such an object, the method for producing a hydraulic inorganic laminate according to the present invention comprises a plurality of layers having different blending amounts of reinforcing fibers with respect to the hydraulic inorganic substance. In obtaining a hydraulic inorganic laminate, a plurality of uncured molded bodies obtained from hydraulic inorganic compositions having different blending amounts of reinforcing fibers are laminated in a desired layer configuration,
In this laminated state, pressure molding is performed while applying vibration.

In the above structure, the number of layers constituting the laminate is not particularly limited, but it is preferable that the number of layers is two. The hydraulic inorganic composition refers to an inorganic substance that exhibits curability when kneaded with water, that is, a composition that contains a hydraulic inorganic substance as a main component. The hydraulic inorganic material is not particularly limited, for example, ordinary Portland cement, special Portland cement, alumina cement, single cement such as Roman cement, acid-resistant cement, fire-resistant cement, special cement such as water glass cement, gypsum, lime,
Air-hardening cement such as magnesia cement can be mentioned, and especially Portland cement in terms of strength and fire resistance,
Alumina cement is preferably used. These may be used alone or in combination of two or more.

When the amount of water added to the hydraulic inorganic substance is reduced, the hydraulic inorganic substance is not sufficiently cured,
If the dispersibility of the composition is reduced and the amount thereof is increased, the strength of the finally obtained cured product is reduced. Therefore, the hydraulic inorganic substance 1
25 to 40 parts by weight is preferable with respect to 00 parts by weight. The reinforcing fiber used in the present invention may be any one depending on the performance desired to be imparted to the laminate, for example, vinylon, polyamide, polyester, polypropylene, aramid,
Synthetic fibers such as rayon, carbon fibers, glass fibers, potassium titanate, inorganic fibers such as steel, and natural fibers such as pulp and hemp can be used. These may be used alone or in combination of two or more.

If the fiber diameter of the above-mentioned reinforcing fiber becomes too thin, it will be re-aggregated during mixing and fiber balls will be easily formed by entanglement, and the strength of the finally obtained cured product will not be further improved. If the fiber diameter becomes thicker or the fiber length becomes too short, the reinforcing effect such as improvement in tensile strength is small, and if the fiber length becomes too long, the dispersibility and orientation of the fibers tend to decrease. It is preferable that the fiber diameter is 0.1 to 40 denier and the fiber length is about 1 to 15 mm.

When the amount of the reinforcing fiber is small, the reinforcing effect cannot be obtained, and when the amount is large, the dispersibility of the fiber and the adhesiveness at the laminating interface are deteriorated. Therefore, for example, when a laminated body composed of two layers is obtained, The first hydraulic inorganic composition constituting the layer 1 is obtained by adding 0.5 to 3.0 parts by weight of the reinforcing fiber to 100 parts by weight of the hydraulic inorganic substance to form the second layer. As the hydraulic inorganic composition, it is preferable to use one in which 3.5 to 7 parts by weight of the reinforcing fiber is added to 100 parts by weight of the hydraulic inorganic material.

In the present invention, a water-soluble polymer material, an inorganic filler, etc. may be added to the hydraulic inorganic composition as needed. As a water-soluble polymeric substance, it dissolves in water to give viscosity, and enhances the fluidity of the composition obtained from the hydraulic inorganic substance and water to improve the shapeability. It is not particularly limited as long as it is a polymer substance that can absorb excess water in the body and serve as an adhesive that fills voids between cement particles, and examples thereof include cellulose ethers such as methyl cellulose, hydroxymethyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, and hydroxypropyl methyl cellulose. , Polyvinyl alcohol, polyacrylic acid, lignin sulfonate, and the like.

If the amount of the water-soluble polymer substance added increases, the water resistance of the finally obtained cured product tends to decrease, so the amount added is 5 parts by weight per 100 parts by weight of the hydraulic inorganic substance. It is preferably not more than a part. The inorganic filler is not particularly limited as long as it does not dissolve in water, does not inhibit the curing reaction of the hydraulic inorganic substance, and does not significantly inhibit the action of any constituent material used in the production method of the present invention, For example, aggregates for cement mortar such as silica sand and river sand,
Mixture for mixed cement such as fly ash, silica flower, silica fume, bentonite, blast furnace slag, natural minerals such as sepiolite, wollastonite, mica, etc.
Examples include calcium carbonate and diatomaceous earth. For the purpose of further reducing the weight, inorganic natural foam materials such as silica balloons, perlite, fly ash balloons, shirasu balloons, glass balloons and foamed and baked clay may be used.
These may be used alone or in combination of two or more.

When the average particle size of the inorganic filler is small, it becomes difficult to produce a molded product, and when it is large, the particles of the inorganic filler tend to be difficult to disperse, so that the average particle size is 0.03 to 500 μm. Something is preferable. Furthermore, since the dispersibility of the reinforcing fiber tends to decrease when the amount of the inorganic filler decreases, 100 parts by weight or less is preferable with respect to 100 parts by weight of the hydraulic inorganic substance.

The method for producing the uncured molded body is not particularly limited, but generally, first, a hydraulic inorganic substance,
Water, a reinforcing fiber and, if necessary, a water-soluble polymer substance and an inorganic filler are mixed to obtain a hydraulic inorganic composition. Next, the hydraulic inorganic composition can be obtained by extruding it with an extruder. As a method of giving vibration during press molding, generally, a method of vibrating the press mold while press molding with a press mold is used, for example, by attaching a vibration motor, a vibrator, a vibrator or the like to the press mold. A method of vibrating the pressing die may be used.

If the vibration frequency of the vibration applied to the pressing die is too low, the fluidity of the composition in the die tends to be poor, and if it is too high, a large amount of energy tends to be required to apply the vibration. Therefore, a frequency of about 100 to 10,000 Hz is preferable. If the amplitude of the vibration is too small, the fluidity of the extruded composition in the mold tends to be poor, and if it is too large, the linearity of the obtained molded article tends to be deteriorated, so about 1 to 500 μm. Is preferable.

The direction in which the pressing die is vibrated is not particularly limited, and may be the vertical direction, the horizontal direction, or the diagonal direction. Incidentally, as an apparatus used for such vibration pressure molding, for example, there is a "vibration press molding machine" described in the Tokoname Ceramics Technology Center Research Results Report in 1988.

In order to obtain a desired cured product from the press-molded laminate, natural curing may be carried out for a long time.
Slow curing reaction For example, when using a hydraulic inorganic substance such as Portland cement, the curing reaction can be promoted by conventionally known methods, such as heating and humidifying the laminate for autoclave curing, improving mechanical properties. can do.

[0019]

According to the above construction, when a plurality of uncured molded bodies are laminated and pressure-molded while applying vibration, the components of each layer are mixed by vibration at the laminated interface of each uncured molded body. .

[0020]

EXAMPLES Examples of the present invention will be described in more detail below in comparison with comparative examples. (Examples 1 to 7, Comparative Examples 1 to 5) After obtaining a hydraulic inorganic composition to be the first layer or the second layer having the blending composition shown in Table 1 or Table 2, the composition was extruded in the respective extrusion directions. To 100
Screw diameter 1 with a die having a parallel part of mm
It was extrusion-molded with a 00 mm vacuum extrusion molding machine (MV-FM-A-1 type) to form plate-shaped first and second uncured molded bodies having a width of 200 mm and a thickness of 6 mm and different fiber amounts.

150 mm of the two uncured molded bodies obtained
After cutting into a size of 150 mm, a vibration press molding machine (Asahi Engineering Co., Ltd., trade name: SA-50)
Layered on and supplied at a pressure of 30 kg / cm ² for 5 seconds,
Press-molding was performed while applying a vibration with a frequency of 1000 Hz and an amplitude of 10 μm to obtain a flat plate-shaped laminate of 300 mm × 300 mm × 6 mm. However, no vibration was applied to Comparative Examples 1 to 3.

Then, the obtained laminated body is treated at 60 ° C. and 90%.
Curing was carried out in RH for 6 hours to obtain a cured product. The cured product thus obtained was subjected to the following physical property evaluation tests, and the results are also shown in Tables 1 and 2. In addition, Table 1,
Each component in 2, ie, cement is ordinary Portland cement (manufactured by Onoda Cement Co., Ltd.), and fly ash is JIS A 6201 equivalent (true specific gravity 2.3, bulk specific gravity 0.6: manufactured by Kanden Kako). The vinylon fiber has a fiber diameter of 15 μm and a fiber length of 3 mm, and the polypropylene fiber has a fiber diameter of 20 μm and a fiber length of 3 m.
The viscosity of a 2% aqueous solution at 20 ° C. is 30000 cp.
s is shown.

Further, the composition of each layer contains each component in a volume of 70
3 in a liter Erich mixer (made by Erich)
Mix for minutes, add a predetermined amount of water to the resulting mixture,
Obtained by mixing for an additional 2 minutes. Further, the hydraulic inorganic composition obtained upon extrusion molding was previously kneaded with a clay kneader (MP-100 type, manufactured by Miyazaki Iron Works Co., Ltd.).

[Physical Property Evaluation Test] (1) Bending Strength The obtained cured product was cut to obtain a test piece, and the bending strength was measured by JI.
It was measured according to the method of S A 1408. (2) Drop ball test The obtained cured product was cut into 300 mm square pieces to obtain test pieces.
It is measured according to the method of JIS A 5423, water is applied to the test piece to determine the occurrence of cracks depending on the presence or absence of water permeability,
It showed the lowest falling ball height at which cracking was observed. (3) Freeze-thaw property A test piece was obtained by cutting the obtained cured product, and
Freezing and thawing was performed according to the method of 666A, and after 300 cycles, the test piece was taken out, and the bending strength was measured in the same manner as the above bending strength, and the strength retention was shown.

[0025]

[Table 1]

[0026]

[Table 2]

[0027]

EFFECTS OF THE INVENTION Since the method for producing a hydraulic inorganic molded body according to the present invention is constituted as described above, the composition constituting each uncured molded body is mixed at the laminating interface due to the vibration during press molding. Molded into a matched laminate. Then, when this laminated body is cured, a hydraulic inorganic cured body having a high strength and impact resistance with a small fiber content and excellent durability can be obtained.

Claims (1)

[Claims] 1. To obtain a hydraulic inorganic laminate comprising a plurality of layers having different amounts of reinforcing fibers mixed with respect to the hydraulic inorganic substance, a plurality of unprepared hydraulic inorganic compositions obtained by mixing different amounts of reinforcing fibers are used. A method for producing a hydraulic inorganic laminate, which comprises laminating a cured molded article in a desired layer constitution and press-molding the laminated state while applying vibration.