JP2001316164A - Inorganic hydraulic composition and method for manufacturing lightweight molded body using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inorganic hydraulic composition free from asbestos and a method for manufacturing a light-weight noncombustible formed body with excellent dimensional stability using the composition. SOLUTION: The composition comprises the inorganic hydraulic material, a silicate material, a fiber material and a light-weight aggregate. A mixture of the following hydraulic composition 1), 2) and water is kneaded, extruded, cured in an autoclave and hardened: the composition 1) a silica powder whose specific surface area and SiO2 content are >=5000 cm2 and <8000 cm2/g and >=90 wt.% respectively. Molar ratio of CaO/SiO2 is 0.5-1.2. the composition 2) a water-absorbing mineral fiber and/or a water-absorbing inorganic artificial fiber except the asbestos whose total amount is >=5 wt.% and <=50 wt.% are contained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inorganic hydraulic composition used for, for example, an outer wall material, a ceiling material, an interior material, etc. of a building, an inorganic lightweight molded article comprising the same, and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, mortar coating has been most often used on the outer walls of detached houses and low-rise buildings. However, recently, a method using a molding plate such as siding has been used in many cases. As the molded plate, cement-based,
Gypsum-based, calcium silicate-based inorganic hydraulic materials such as those manufactured from the main raw material is often used,
It is widely used not only for exterior walls, but also for housing ceilings and interior materials.

[0003] However, when these molded plates are used for the outer wall, the molded plates expand due to moisture absorption due to the humidity in the air, water absorption due to the entry of rainwater, and the like, and thereafter, the molded plates contract due to drying. By changing the water content of the molded plate in this way, the expansion and contraction of the molded plate repeatedly occur,
Warping or undulation occurs in the formed plate. When warping or swelling occurs in the formed plate, not only does the appearance worsen, but also there is a gap in the joint between the formed plates, the gap between the formed plate and the sash, etc., due to the ingress of rainwater from the gap, Corrosion of the hulls and columns in the walls causes a decrease in the strength of the structure, leading to a decrease in the durability of the entire building. Further, when the formed plate is applied to the outer wall, sealing is applied to the joint. However, when the formed plate is greatly shrunk by drying, the joint width is widened, the sealing breaks, and rainwater enters from there. Therefore, when the rate of change in the length of the formed plate is large, not only the outer wall is deteriorated, but also the durability of the entire building is reduced.

[0004] Further, the conventionally used molded plate has a great problem in terms of processing, transportation and construction due to its excessive weight, and it is desired to produce a lightweight molded body.
Attempts to reduce the weight of these inorganic molded bodies have been made for a long time. For example, by adding an inorganic lightweight aggregate such as pearlite or shirasu balloon or a synthetic resin having a water absorbing property to a compound containing a hydraulic material, a fine aggregate, a fibrous material, etc., the weight of the inorganic molded body can be reduced. Is being done.

[0005] Among these methods for reducing the weight of the inorganic molded article,
When adding an inorganic lightweight aggregate made of a foam of an inorganic substance such as pearlite, mixing and kneading, the aggregate is easily broken by an external force received when performing extrusion molding,
It was difficult to achieve sufficient weight reduction.

Further, when a water-absorbent resin is used as disclosed in Japanese Patent Publication No. 6-84268, the water-absorbent resin itself is destroyed by an external force received during mixing, kneading and extrusion, and the particle size of the water-absorbent resin is reduced. The wide distribution increases the range of pores in the product, worsens the nailability, and delays the curability of the hydraulic material due to the incorporation of a large amount of water, resulting in lower initial strength. There was a problem that would. If the initial strength is low, there is a risk that the molded product may be cracked or chipped during transportation during the curing process after molding. Further, there is a problem that the resin in a water-absorbing state is easily aggregated during mixing and kneading, and it is difficult to produce an inorganic molded body in a uniform dispersion state.

On the other hand, as a lightweight building material, AL
A concrete board called C is manufactured,
Although ALC is lightweight, it has a drawback that it has high water absorption and extremely poor frost damage resistance.

In the production of an inorganic molded article, asbestos has conventionally been added as a fibrous raw material. Asbestos has a water retention ability to retain the added water in the system and a shape retention force to maintain the shape after molding, so that the addition of excessive moisture impairs the moldability and shape retention. Thus, it was possible to produce a molded article without any problem, and it was easy to reduce the weight of the molded article due to dissipation of the added excess moisture. However,
In recent years, the harmfulness of asbestos to the human body has been pointed out, and its use has been greatly reduced, and a method for producing a lightweight molded article by blending without adding asbestos has been studied. Generally, the water content when the molded plate is applied as an outer wall material varies between about 5% by weight and 10% by weight. Conventionally, however, the inorganic lightweight molded body generally used for ceramic siding is generally used. Water content 10% to 5% by weight
The rate of change in length between the two is usually about 0.02 to 0.03 or more, and improvement thereof has been desired.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned drawbacks of the prior art, and to provide a very excellent dimensional stability, light weight, and a base material test disclosed in the Ministry of Construction Notification No. 1828, which is free of asbestos. An object of the present invention is to provide a non-flammable inorganic lightweight molded article.

[0010]

SUMMARY OF THE INVENTION In order to achieve the above object, an inorganic hydraulic composition according to the present invention comprises an inorganic hydraulic material, a silicate material, a fibrous material, and a lightweight aggregate. Which satisfies at least one of the following 1) and 2). 1) exceeds the specific surface area 5000 cm ² / g as siliceous materials, of less than 8000 cm ² / g, and the content of SiO ₂ is used silica powder is 90 wt% or more, Ca in the composition
The molar ratio of O / SiO ₂ is in the range of 0.5 to 1.2. 2) The fiber material contains water-absorbing natural mineral fibers other than asbestos and / or water-absorbing inorganic artificial fibers in a total amount of 5% by weight or more and 50% by weight or less.

As the water-absorbing natural mineral fiber, at least one fiber selected from the group consisting of wollastonite, sepiolite and attapulgite can be used, and as the water-absorbing inorganic artificial fiber, rock is used. Wool can be used. As the lightweight aggregate, expanded thermoplastic resin particles having an expansion ratio of 10 times or more and 100 times or less can be used. The thermoplastic resin expanded particles have a particle size of 10 μm or more and 1
Those having a size of 300 μm or less are preferred. As the thermoplastic resin foam particles, at least one kind of foam particles selected from the group consisting of acrylonitrile resin foam particles, vinylidene chloride resin foam particles, and styrene resin foam particles can be used. As the styrene-based resin expanded particles, those having an expansion ratio of 20 times or more and 50 times or less and an average particle size of 300 μm or more and 1300 μm or less are suitably used, and more preferably an expansion ratio of 20 times or more and 50 times or less.
The average particle size is 300 μm or more and 700 μm or less. As the lightweight aggregate, in addition to the thermoplastic resin foam particles, an average particle diameter of 50 μm or more
It can contain an inorganic lightweight aggregate containing an aluminum oxide component of not more than 00 μm, a bulk specific gravity of 0.1 or more and 0.7 or less, a pressure resistance of 8 MPa or more, and 20% by weight or more and 50% by weight or less.

Further, the inorganic lightweight molded article of the present invention is obtained by adding water to the above-mentioned inorganic hydraulic composition, mixing, molding and curing, and having a water content of 10% by weight to 5%. It is an inorganic lightweight molded article having a length change ratio of 0.01% or less between weight% and a specific gravity of 1.1 or less, and adding water to the above-mentioned inorganic hydraulic composition and mixing it. After being molded, it is cured in an autoclave and has a specific gravity of 1.1 or less and a bending strength of 6.5 N / m.
m ² or more.

Further, the method for producing an inorganic lightweight molded article according to the present invention is characterized in that water is added to the above-mentioned inorganic hydraulic composition, mixed, molded, and then autoclaved. .

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION As the inorganic hydraulic material used in the present invention, ordinary portland cement, low alkali type portland cement, early strength portland cement,
Examples include cements such as ultra-high strength Portland cement, blast furnace cement, silica cement, fly ash cement, magnesia cement, and alumina cement, and calcareous materials such as hemihydrate or anhydrous gypsum and gypsum. These may be used alone or in combination of two or more. However, like the siliceous material, a material having a large specific surface area, for example, a material having a specific surface area of 3000 cm ² / g or more is preferable.

That is, as a method of obtaining a high-strength molded article without using asbestos, conventionally, a method of adding water to a mixed composition, mixing the resulting composition, curing the composition, curing the composition, and curing it in an autoclave is performed. Has been done. This is because a very stable crystal called tobermorite is formed in a molded article by curing at high temperature and pressure such as autoclave curing, and when all the products in the molded article are this crystal, It is known that a molded article having the highest dimensional stability, the highest strength, and the excellent freeze-thaw resistance can be obtained. If the specific surface area of the inorganic hydraulic material is large, the reaction amount for producing tobermorite increases,
Furthermore, the more the CaO component in the inorganic hydraulic material,
A large amount of tobermorite can be produced with a small amount of contamination. Therefore, as the inorganic hydraulic material, ordinary Portland cement and early-strength Portland cement containing a large amount of CaO component are suitable.

The amount of the inorganic hydraulic material is in the range of 20% by weight to 90% by weight, preferably 25% by weight to 80% by weight, based on 100% by weight of the solid content of the composition. . The amount of the inorganic hydraulic material is 25
When the amount is less than 90% by weight, the strength of the molded body tends to decrease due to the shortage of the hardening material. In the present invention, the solid content of the composition,
It refers to inorganic hydraulic materials, siliceous materials, fibrous materials, aggregates, admixtures, admixtures, etc., other than water and thickeners.

One of the technical measures adopted in the present invention is
Specific surface area 5000cm ^Two/ G, 8
000cm^Two/ G and SiO_Two90% by weight
% Or more, and CaO / SiO in the composition is used.
_TwoIs in the range of 0.5 to 1.2, preferably
The range is 0.6 to 1.0.

The mixing amount of the inorganic hydraulic material and the siliceous material is adjusted so that CaO (calcium oxide) / Si
It is said that by setting the molar ratio of O ₂ (silicon dioxide) in the range of 0.7 to 1.0, a large amount of tobermorite can be produced. However, ordinary Portland cement, which is generally used as an inorganic hydraulic material, and early-strength Portland cement have a specific surface area of about 3000 to 5000 cm ² / g, and the difference in specific surface area due to the type difference is small. Silica sand, silica stone powder, fly ash, etc. used as siliceous materials
The component ratio and specific surface area of SiO ₂ vary greatly depending on the type, and only by specifying the molar ratio of CaO / SiO ₂ in the composition to the above range, required flexural strength, dimensional stability, freeze-thaw resistance and the like are required. It was difficult to obtain a molded body having performance.

That is, in general, the process in which particles react is expanding from the surface to the inside, and since the thickness of the formed phase is the same for both large and small particles, the smaller the particles, the larger the surface area. , The reaction will be fast.
In particular, the autoclave curing is performed in a short time unlike the hydration reaction, and it is considered that the reaction amount increases as the number of fine particles increases. On the other hand, conventionally used silica sand has a large particle size, even the finest No. 8 silica sand has a particle size of about 50 μm to 200 μm, and a specific surface area of about 1500 cm ² / g.
It is considered that the amount of reaction between the silica sand and the inorganic hydraulic material is small, and the formation of tobermorite is insufficient, and a molded article having sufficient dimensional stability and bending strength cannot be obtained.

Thus, the CaO /
It is difficult to obtain a molded body having sufficient physical properties only by defining the molar ratio of SiO ₂ , and it is necessary to use silica powder having predetermined properties as in the present invention, and to further improve the C content in the composition.
By setting the molar ratio of aO / SiO ₂ to a predetermined range,
By generating a lot of very stable crystals, called tobermorite, in the molded article during autoclave curing, the rate of change in the length of the molded article can be reduced, and high bending strength can be obtained. If the molded article is lightened using lightweight aggregates,
The bending strength decreases in proportion to the specific gravity, and there is a danger of cracking or cracking during transportation or construction. On the other hand, in the present invention, the use of silica powder under the above conditions increases the strength of the matrix portion other than the aggregate, so that a sufficient reduction in the weight of the molded body can be realized.

In the present invention, silica powder having a specific surface area of more than 5000 cm ² / g and less than 8000 cm ² / g is used as the siliceous material. This means that the specific surface area is 5000 cm ²
/ G or less, the amount of reaction with the inorganic hydraulic material (calcical material) is reduced, and sufficient tobermorite is not generated, so that the effect of autoclave curing is not exhibited and the dimensional stability of the molded product is reduced. In addition, the bending strength and the freeze-thaw resistance of the molded product are also reduced. On the other hand, the specific surface area is 8
When it is 000 cm ² / g or more, not only does the flowability when extruding by adding water decrease, the moldability deteriorates, but also the structure of the molded product becomes too dense and the specific gravity of the molded product increases. Further, in order to obtain silica stone powder having a large specific surface area, processing is troublesome, and the material cost is increased. Therefore, when viewed from the performance and cost aspects, as the specific surface area of the silica stone powder beyond 5000 cm ² / g, it is suitable which fall within the scope of less than 8000 cm ² / g.

The specific surface area of the siliceous material is measured according to JI
It was carried out using a Blaine air permeation apparatus in accordance with the specific surface area test of SR 5201 “Physical test method of cement”.

Also, in the present invention, as the siliceous material, S
Silica powder having an iO ₂ content of 90% by weight or more is used. If the content of SiO _{2 in} the silica powder is low, it must be mixed in a large amount, and the specific gravity of the molded product increases. Note that Si
Components other than O ₂ can include various components such as calcium oxide, aluminum oxide, iron oxide, potassium oxide, sodium oxide, and loss on ignition (sometimes denoted as Ig.loss.). These components are not separately mixed but are components contained in the silica powder.

The mixing amount of the inorganic hydraulic material and the siliceous material in the inorganic hydraulic composition of the present invention depends on the content of CaO in the inorganic hydraulic material, the content of SiO _{2 in} the siliceous material, and the content in the composition. Although it depends on how the molar ratio of CaO / SiO ₂ is defined, for example, the inorganic hydraulic material 20
About 70% by weight and about 10 to 60% by weight of the siliceous material.

By the way, as the siliceous material, there is fly ash conventionally used generally. However, the content of SiO _{2 in} fly ash is about 55% by weight, and in order to make the SiO ₂ component in the composition using fly ash the same as that using silica powder, it is necessary to compare with silica powder. Therefore, it is necessary to mix a large amount of fly ash, and the fly ash contains a small amount of unburned coal, which is not preferable because the non-combustibility of the molded article is reduced.

The mixing amount of the inorganic hydraulic material and the silica powder in the inorganic hydraulic composition of the present invention depends on the amount of CaO / Si in the composition.
The mixing ratio is such that the molar ratio of O ₂ falls within the range of 0.5 to 1.2, preferably 0.6 to 1.0. If the above molar ratio is larger than 1.2, CaO becomes larger than SiO ₂ , so that lime becomes excessive, and products other than tobermorite are generated, and the strength of the molded body is reduced. On the other hand, when the above molar ratio is less than 0.5, silica becomes excessive and stable tobermorite can be formed, but unreacted silica remains as aggregate as it is. The above molar ratio is 0.5 to 1.2, preferably 0.1 to 0.2.
In the range of 6 to 1.0, only tobermorite is formed in the molded product, which is the most preferable state.

Further, other technical means adopted in the present invention include:
As an alternative to asbestos, an inorganic fiber having a water absorbing property other than asbestos is used. That is, a total of 5% by weight or more and 50% by weight or less of a natural mineral fiber having water absorbency and / or an artificial artificial fiber having water absorbency as a fibrous material is contained in the composition (when the solid content is 100% by weight). It is to do.

Examples of the natural mineral fibers include wollastonite, sepiolite, attapulgite, halloysite, fibrous gypsum (gypsum), and mordenite (zeolite). Examples of the inorganic artificial fibers include rock wool. These are appropriately selected according to the required physical properties of the molded article so that the characteristics can be utilized.
Since these inorganic fibers have a large surface area and a large tensile strength, when mixed into a molded article, they restrict expansion or contraction of the paste portion in the molded article, thereby reducing the rate of change in the length of the molded article. Can be. In addition, these inorganic fibers have many needle-like crystals, and a molded article using the inorganic fibers has excellent bending strength and impact resistance.

On the other hand, the amount of cellulosic fiber, thermoplastic resin compounded for weight reduction, and synthetic fiber compounded for improving impact resistance is limited because they are combustible. It was necessary to sacrifice weight reduction and impact resistance. On the other hand, the inorganic fiber can be mixed in an amount sufficient to improve the dimensional stability, bending strength and impact resistance without decreasing the incombustibility of the molded article even if the mixed amount is increased.

These natural mineral fibers and inorganic artificial fibers are not limited as long as they have a water-absorbing property and are not limited in terms of type, material, properties and the like, but may be 30% by weight or more, preferably 100% by weight or more. Those having water absorbency are preferred. These water-absorbing natural mineral fibers and water-absorbing inorganic artificial fibers are only required to be contained in the composition in a range of 5% by weight to 50% by weight in total.
Both may be used together or used alone.

Among the above natural mineral fibers and inorganic artificial fibers, wollastonite, sepiolite and attapulgite are used as natural mineral fibers having water absorption, and rock wool is used as inorganic artificial fibers having water absorption. Is preferably used.

Wollastonite is calcium metasilicate, also called wollastonite, and is acicular in shape, excellent in heat resistance,
It has the characteristic that the coefficient of thermal expansion is small. There are many types of wollastonite having different shapes, fiber lengths, and fiber diameters, but wollastonite used in the present invention is not particularly limited.

Sepiolite is a hydrous magnesium silicate which is porous, has a large specific surface area, and has a hydroxyl group on its surface, so that it has good affinity for water and alcohol, and has good heat resistance. It has the feature of maintaining its properties as a fibrous substance.

Attapulgite is a hydrated magnesium aluminum silicate having a hollow needle-like crystal structure, a large cation substitution capacity and a large specific surface area, so that it has excellent water absorbency and good heat resistance.

Rock wool includes those using rock as a main raw material and those using slag, both of which have good incombustibility.

The characteristics of each inorganic fiber are as follows. Wollastonite and rock wool have a slightly higher specific gravity of 2.5 to 2.9, and the water absorption is smaller than that of sepiolite.
The reinforcing effect is high, and the dimensional stability and bending strength of the molded product can be greatly improved. Sepiolite and attapulgite have a specific gravity of about 2 to 2.2 and a large specific surface area, so they have a large water absorption and a large weight saving effect.

Further, these water-absorbing inorganic fibers are:
Since it has water retention, it retains the water in the slurry, gives lubricity to the inorganic hydraulic composition at the time of extrusion, improves extrusion moldability, and also provides reinforcement and mold retention at the time of uncuring. As a result, the hollow portion does not sag when extruded into a hollow shape, and a shape as designed can be obtained. Further, these inorganic fibers having water absorbability also make it possible to reduce the weight of the molded body due to dissipation of the added excess moisture.

The amount of the water-absorbing inorganic fiber in the inorganic hydraulic composition of the present invention, when the solid content of the composition is 100% by weight, is preferably 5% by weight or more and 50% by weight or less. Ranges from 10% by weight to 35% by weight. If the amount of the inorganic fiber is less than 5% by weight, the water retention performance is not exhibited, and the effect of improving the moldability is hardly obtained. Further, it is difficult to obtain the effects of improving the dimensional stability of the molded product, the bending strength of other properties, and the impact resistance. Also 50
If the content exceeds% by weight, the ratio of components other than the inorganic fibers becomes too low, and the surface properties of the molded product deteriorate. In particular, a decrease in the component ratio of the inorganic hydraulic material leads to a decrease in bending strength.

In the present invention, as described above, 1) the specific surface area of the siliceous material exceeds 5000 cm ² / g,
Less than 0 cm ² / g and the content of SiO ₂ is 90% by weight
Using the silica powder described above, CaO / SiO ₂ in the composition
2) a natural mineral fiber having a water absorbing property other than asbestos and / or an inorganic synthetic fiber having a water absorbing property other than asbestos as a total of 5% by weight or more. Only one of the technical means may be employed, or both of the technical means 1) and 2) may be employed simultaneously. The use of both of the methods 1) and 2) is preferable for improving the rate of change in length. In the present invention, a fibrous material other than the above-described water-absorbing inorganic fibers can be used as long as the effects of the present invention are not impaired.

As the fibrous material other than the water-absorbing inorganic fiber, a cellulosic fiber material is preferably used.
The material and properties of the cellulosic fiber are not limited, but used newspaper, pulp fiber and the like are preferably used. In addition to the cellulosic fiber material, glass fiber, carbon fiber, iron wire, slag wool, inorganic fiber such as potassium titanate, polypropylene fiber, vinylon fiber, acrylic fiber, polyethylene terephthalate (PE
T) It is also possible to add synthetic fibers such as fibers. Cellulosic fibers may be used alone, or a mixture of cellulosic fibers and inorganic fibers, or a mixture of cellulosic fibers and organic fibers may be used.

Cellulose-based fibers are suitably added because they have a reinforcing effect and a water-retaining effect when present in the material, and contribute to the shape-retaining and lightening effects of the molded article. However, synthetic fibers, when used alone, have a reduced reinforcing effect, which is considered to be due to a decrease in fiber strength during curing at high temperatures, and when inorganic fibers other than inorganic fibers having water absorbency are used alone, the specific gravity is reduced. Is not preferable because the specific gravity of the molded article is increased because of its large size, contrary to the reinforcing effect.
These fiber materials may be used alone or as a mixture of two or more.

The fibrous material as described above can be added in an amount which does not impair the effects of the present invention. However, when the solid content is 100% by weight, it is preferably 1% by weight or more and 60% by weight or less. Is added in the range of 1.5% by weight or more and 40% by weight or less, and by setting the proportion of the fibrous material in the composition in such a range, a good molded product can be obtained.

As the expanded thermoplastic resin particles used as the lightweight aggregate in the inorganic hydraulic composition of the present invention, those having an expansion ratio of 10 to 100 times are preferably used. If the expansion ratio is less than 10 times, the effect of reducing the weight cannot be sufficiently exhibited, and if it is more than 100 times, the strength of the molded article tends to decrease, which is not preferable.

It is preferable that the thermoplastic resin foam particles have an average particle diameter of 10 μm or more and 1300 μm or less. When the average particle diameter of the thermoplastic resin expanded particles is smaller than 10 μm, the specific gravity of the molded body tends to increase by being filled in gaps between the materials at the time of producing the molded body, and when the average particle diameter is larger than 1300 μm, Due to the springback phenomenon that occurs when the molding pressure is removed, minute cracks are easily generated inside the molded body, causing a decrease in the strength of the molded body, and also tending to cause unevenness on the molded body surface after molding Having.

The foamed thermoplastic resin particles used in the present invention are not particularly limited as long as they have the above-mentioned characteristics. Even if one kind of foamed thermoplastic resin particles is added, two or more kinds of foamed thermoplastic resin particles may be used. Although there is no problem even if the thermoplastic resin foam particles are used in combination, especially acrylonitrile-based resin foam particles,
Expanded vinylidene chloride-based resin particles and expanded polystyrene-based resin particles are preferably used.

The expanded acrylonitrile-based resin particles and expanded vinylidene chloride-based resin particles are preferable because foamed particles having a high expansion ratio and small particle size can be easily produced, and springback upon release of pressure is small. Further, the foamed acrylonitrile resin particles have a softening point of the cell wall of 140.
° C, which is higher than 80 ° C of vinylidene chloride-based resin, so that when the formed molded body is cured by steam curing, the resin is hardly softened, and the inside of the molded body due to the deformation of the foamed particles is reduced. This is more preferable because the generation of fine cracks can be suppressed. These expanded acrylonitrile resin particles and expanded vinylidene chloride resin particles preferably have an expansion ratio of 15 to 80 times, more preferably 20 to 70 times, and a particle size of 10 μm to 10
0 μm or less, more preferably 20 μm or more and 80 μm or less.

The expanded styrene resin particles used as a lightweight aggregate in the inorganic hydraulic composition of the present invention preferably have an expansion ratio of 20 to 50 times and an average particle diameter of 300 to 1300 μm. Are preferably used, and more preferably those having an expansion ratio of 20 times or more and 50 times or less and an average particle size of 300 μm or more and 700 μm or less are used. Such styrene-based resin foamed particles are lower in production cost than acrylonitrile-based resin foamed particles and vinylidene chloride-based resin foamed particles, and are particularly preferable as a lightweight material used in the present invention.

When the average particle diameter of the expanded styrene resin particles is 300 μm or more and 700 μm or less, the expanded styrene resin particles are not recognized on the surface of the molded article, and the molded article has extremely good surface properties. In contrast, the average particle size was 7
When foamed styrene-based resin particles larger than 00 μm are used, the surface properties of the molded article are slightly reduced, but the other properties are not particularly problematic, and the production cost is lower than that of a small particle size. It can be offered to the market at low cost. However, when the average particle diameter of the expanded styrene resin particles is larger than 1300 μm, fine cracks and defects are easily generated inside the molded body due to a springback phenomenon that occurs when the molding pressure is removed. However, it is not preferable because the surface property of the molded article after molding tends to be deteriorated.

Such a method for producing expanded styrene resin particles is carried out, for example, in a reactor equipped with a stirrer charged with a continuous phase (eg, water) in which the monomer and the resulting polymer are substantially insoluble. Is dispersed as small droplets and then continuously stirred to polymerize under predetermined conditions.
An example of a specific manufacturing method is as follows. A styrene monomer represented by styrene, water, calcium phosphate, in a pressure-resistant reactor equipped with a stirrer and a temperature detection tube,
A polymerization initiator such as sodium dodecylbenzenesulfonate, benzoyl peroxide and tert-dibutyl perbenzoate was charged, and nitrogen was introduced with stirring until the pressure in the reactor reached a predetermined pressure. The polymerization is carried out for a time. Next, a foaming agent such as butane, pentane, hexane or the like is added and the temperature is raised to a predetermined temperature, and then the foaming agent is impregnated for a predetermined time. This is cooled to room temperature to obtain true spherical expandable styrene resin particles. Moisture is removed from the resin particles using a dryer and dried.
The resin particles are sieved to obtain particles having a predetermined particle size, and the obtained expandable styrene resin particles are then expanded with a heat medium such as steam to expand the styrene resin particles having a predetermined expansion ratio and particle size. Get the particles. The method for producing the expanded styrene resin particles used in the present invention is not limited at all, and it goes without saying that methods other than those described above are suitably used.

The styrene-based resin for producing the styrene-based resin expanded particles may be a homopolymer of a styrene-based monomer or a copolymer of a styrene-based monomer and another copolymerizable monomer. However, a homopolymer and a copolymer of a styrene monomer are preferably used, and a homopolymer of a styrene monomer and a polystyrene resin are more preferably used. As the styrene monomer, styrene,
Vinyl naphthalene, alkyl-substituted styrene, halo-substituted styrene, divinylbenzene, divinyltoluene, divinylxylene, divinylnaphthalene, trivinylbenzene, and the like, as the copolymerizable monomer, an alpha olefin having 2 to 12 carbon atoms, It is selected from cyclic olefins such as cyclopentene and norbornene, dienes such as 1,4-hexadiene and methyl-1,4-hexadiene, and vinyl monomers such as vinyl chloride, vinylidene chloride, acrylonitrile, vinyl acetate, acrylic acid, and methacrylic acid. One or more kinds may be mentioned.

The content of the expanded thermoplastic resin particles in the inorganic hydraulic composition of the present invention is preferably 0.1% by weight or more and 3% by weight or less when the weight of the solid content is 100% by weight.
If the amount is less than 0.1% by weight, the effect of reducing the weight cannot be sufficiently exerted. If the amount is more than 3% by weight, fine cracks and defects occur inside the molded body due to a springback phenomenon that occurs when the molding pressure is removed. The strength may be easily reduced.

In the present invention, in addition to the thermoplastic resin foam particles, an average particle diameter of 50 μm or more and 300 μm or less, a bulk specific gravity of 0.1 or more and 0.7 or less, a pressure resistance of 8 MPa or more and 20% or more and 50% by weight or less. It is more preferable to use an inorganic lightweight aggregate containing the above aluminum oxide component.

The addition of pearlite and shirasu balloon having a small pressure resistance, which has been conventionally used as a lightweight aggregate of an inorganic molded article, is likely to cause the lightweight aggregate to be easily broken by an external force received during mixing, kneading and extrusion. It was difficult to achieve sufficient weight reduction. On the other hand, when the inorganic lightweight aggregate having the above-mentioned characteristics is used, it is hard to be broken by the external force received when performing mixing, kneading, and extrusion molding, and it is possible to obtain a lightweight effect by maintaining its shape. .

If the aluminum oxide component of the inorganic lightweight aggregate is out of the range of 20% by weight or more and 50% by weight or less, preferably 25% by weight or more and 50% by weight or less than 8 MPa, the mixed And kneading,
Since the external force at the time of the extrusion molding causes the destruction of the inorganic lightweight aggregate, it is difficult to sufficiently exert the lightening effect.

The pressure resistance of the inorganic lightweight aggregate means the pressure applied when 75% by weight of the inorganic lightweight aggregate remains without being destroyed under hydrostatic pressure.
Specifically, after the aggregate is immersed in water and left for 24 hours, the aggregate floating on the water surface is scooped, dried at 80 ° C. for about 24 hours to remove moisture, and is not destroyed. Obtain aggregate. Thereafter, a predetermined amount of the dried aggregate is put together with water in a tester (for example, a pressure vessel), and pressure is applied (for example, a gas such as nitrogen is added to the center of the pressure vessel).
Leave at the specified pressure for 5 minutes. Then, after taking out the aggregate and water from the tester and allowing it to stand, the aggregate floating on the water surface is filtered, dried at 80 ° C. for 24 hours, and weighed. The pressure when the weight of the suspended aggregate after the test is 75% by weight when the weight of the aggregate put in the container before the test is 100% by weight is defined as the pressure resistance. .

The inorganic lightweight aggregate used in the present invention is:
It is necessary to have a bulk specific gravity of 0.7 or less.
When the bulk specific gravity is larger than 0.7, the effect of reducing the weight cannot be sufficiently exerted, and it is necessary to add a large amount to reduce the weight.

There is no particular limitation on the shape and particle size of the inorganic lightweight aggregate. However, a) suppresses a decrease in pressure resistance, b) improves the flowability of a molding material obtained by adding water to the inorganic hydraulic composition, and c) each component of the composition at the time of producing a molded article The inorganic lightweight aggregate preferably has a spherical shape, and preferably has an average particle size of 50 μm or more and 300 μm or less, for the reason that the specific gravity of the compact is not increased by being filled in the gaps between them. Therefore, as the inorganic lightweight aggregate, alumina silicate balloon (Reball Co., Ltd.), Microcells (Chichibu Onoda Co., Ltd.) and the like are preferably used.

The content of the inorganic lightweight aggregate in the composition can be added in such an amount that the effect of the present invention is not impaired. However, when the solid content is 100% by weight, 1% by weight or more. 50% by weight or less, preferably 3% by weight or more and 30%
It is added in the range of not more than% by weight.

Further, an inorganic lightweight aggregate other than the above-mentioned specific inorganic lightweight aggregate may be added to the inorganic hydraulic composition of the present invention as long as the effect of the present invention is not impaired.

Further, the inorganic hydraulic composition of the present invention includes:
In addition, if necessary, commonly added admixtures such as blast furnace slag, crushed inorganic plates, or wood chips,
Materials derived from a wood-based material such as wood powder can also be added.

Further, when the extrusion molding method is selected as the method for producing a molded article, the inorganic hydraulic composition of the present invention imparts extrusion fluidity to the composition, and maintains the shape of the molded article after extrusion. Molding aids such as methylcellulose and polyethylene oxide can be added to maintain the viscosity. Further, additives such as pigments, dyes, flame retardants, curing accelerators, curing retarders and the like may be used.

Water is added to the inorganic hydraulic composition of the present invention as described above, mixed with water, molded, and cured to obtain an inorganic lightweight molded body having a water content of 10% by weight to 5% by weight. The rate of change in length between weight% can be 0.01% or less and the specific gravity can be 1.1 or less. The specific gravity of the molded body is a true specific gravity of the molded body itself, and in a case of a molded body having a hollow portion, a value ignoring the hollow portion. As described above, when a molded plate made of an inorganic hydraulic composition is applied as an outer wall material, the moisture content of the molded plate increases due to moisture absorption due to humidity in the air, water absorption due to ingress of rainwater, and the like. Expand, and the moisture content is reduced by the subsequent drying, and the molded plate shrinks. Generally, when a molded plate is used as an outer wall material, the water content increases and decreases between about 5% and 10% by weight, and the water content hardly falls outside this range. Therefore, it is important to grasp the length change rate when the water content is between 10% by weight and 5% by weight, and the length change rate during that time is 0.01% or less, preferably 0.005% or less.
% Or less, the most commonly used length 30
Even with a molded plate of 30 mm, the shrinkage amount is as small as about 0.3 mm or less or 0.15 mm or less, and the joint width does not increase after the molded plate is applied to the outer wall. Further, a molded article having a small dimensional change rate is a good molded article with little occurrence of warpage or undulation in a molded plate.

Casting, press molding, and extrusion molding methods are known as methods for producing a molded article from the inorganic hydraulic composition. The inorganic hydraulic composition of the present invention has a hollow cross-sectional shape. Despite being able to manufacture molded articles, and having excellent continuous productivity and being commercially advantageous, a sufficient weight-reducing effect has not been conventionally obtained due to the destruction of weight-reducing materials such as inorganic lightweight aggregates. The effect is particularly exhibited by the extrusion molding method.

In producing an inorganic lightweight molded article from the inorganic hydraulic composition of the present invention, water is mixed with the inorganic hydraulic composition, uniformly mixed and kneaded. The amount of water is 15 parts by weight or more and 10 parts by weight based on the total amount of solids (100 parts by weight).
0 parts by weight or less is preferred. When the amount is less than 15 parts by weight, the flowability of the kneaded material is deteriorated, and not only does the load on the extruder increase, but also uniform extrusion cannot be performed with an increase in the molding pressure, so that a product having a good shape can be produced. When the amount is more than 100 parts by weight, the inorganic hydraulic composition and the excess moisture tend to be separated inside the extruder, and the extrusion itself tends to be difficult. This is not preferable because it exceeds the limit of the shape retention required for maintaining the shape of the formed molded article.

The method of mixing the inorganic hydraulic composition with water is not particularly limited as long as it can be uniformly mixed and kneaded. The molding material thus obtained is extruded by an extruder having a vacuum deaeration tank, and then cured and cured to produce an inorganic lightweight molded body.

There is no particular limitation on the curing method, and ordinary curing methods such as underwater curing, natural curing, steam curing, and autoclave curing under high temperature and high pressure can be applied, but good dimensional stability can be obtained. Autoclave curing is most effective for obtaining a molded product having high bending strength.

The method for curing the autoclave is not particularly limited. Autoclave curing is curing with saturated steam at a high temperature and a high pressure exceeding 100 ° C.
The reaction is performed at a temperature of 0 ° C. or more, more preferably 150 ° C. or more, and further preferably 160 ° C. or more. The curing time can be changed as appropriate depending on the composition of the composition, the curing temperature, and the desired physical properties of the molded body.

Prior to the autoclave curing, a usual curing such as underwater curing, natural curing and steam curing may be performed. In addition, when autoclaving is performed immediately after molding, the molded article is rapidly heated, and significant expansion of bubbles and moisture in the molded article occurs, which tends to cause cracks in the molded article or on the molded article surface.
In order to develop an initial strength that can withstand the inflation pressure, it is preferable to perform these pre-curing.

The inorganic lightweight molded article of the present invention produced by autoclaving in this manner has a specific gravity of 1.
It has a bending strength of 1 or less and 6.5 N / mm ² or more. In addition, the specific gravity of the molded body is a true specific gravity of the molded body itself, and in the case of a molded body having a hollow portion, a value ignoring the hollow portion.

The inorganic lightweight molded article obtained according to the present invention may have any shape. For example, it can be in the form of a board (plate), rod, or pipe.

[0071]

Next, the present invention will be described based on examples and comparative examples, but the present invention is not limited to only these examples. In the following Examples and Comparative Examples, the physical properties and the like of the molded body were measured or evaluated by the following methods.

<True Specific Gravity> The true specific gravity was calculated from the weight of the molded body and the volume obtained by the submersion method. Hollow portions were ignored, and the specific gravity of the molded body itself was described. <Bending strength> It was measured in accordance with JIS A1408. However, the size of the test piece is 50 mm wide x 140 m long
m and a span of 100 mm. <Non-flammability> Evaluated based on the base material test of Ministry of Construction Notification No. 1828. <Impact resistance> Measured according to JIS A1408. An iron ball of 530 g was dropped from a height of 110 cm, and one having no crack penetrating was judged to be acceptable. However, the test piece dimensions were 200 mm x 150 mm. <Length change rate> A measuring pin was attached to both ends of a test piece having a size of 40 mm and a length of 150 mm to obtain a test piece. The test piece is erected in water, and water is absorbed until the weight becomes constant while measuring the weight (W) and length (L). Thereafter, the sample is allowed to stand in a desiccator, and dried until a constant weight is obtained while measuring the weight (W) and the length (L). Then 105
℃ dryer at dried to a constant weight by weight of (W _0),
The length (L ₀ ) is measured and used as a reference, and the moisture content and the rate of change in length are calculated by the following equations. In addition, the length was measured to 1/1000 mm with a dial gauge. Water content (% by weight) = (W−W ₀ ) / W ₀ × 100 Length change rate (%) = (L−L ₀ ) / L ₀ × 100 The values of the water content and the length change rate are plotted on a graph. Then, the amount of change in the length change rate when the water content increases from 5% by weight to 10% by weight is calculated, and then the change in the length change rate when the water content decreases from 10% by weight to 5% by weight is calculated. Calculate the amount of change and record the average value. <Extrusion Moldability> The state of the molded product discharged from extrusion molding was visually observed and evaluated according to the following criteria. Good: A molded product according to the mold is discharged. Poor: Molded product is not discharged according to the mold. <Surface Properties> The surface of the molded article was visually observed and evaluated according to the following criteria. ：: The surface has no dog-tooth-like cracks, swelling, and wavy surface, and has extremely good surface properties. ：: The surface has good surface properties with no dog-tooth-shaped cracks and cracks and no surface waving. ×: Canine-shaped cracks and cracks on the surface, with surface undulations.

(Example 1) An inorganic hydraulic composition having the mixing ratio shown in Table 1 was mixed with a mixer (MHS-M manufactured by Miyazaki Tekko Co., Ltd.).
(Type 165), and wet mixing was performed by adding water in the amount shown in Table 1 after dry mixing. Next, this mixed material was put into an extrusion kneading machine (Miyazaki Iron Works screw diameter 100 φ kneader ruder) and kneaded to obtain a molding material. This molding material is 150 m in width having eight hollow portions.
The extruder was extruded from a vacuum extruder (Honda Tekko extruder) with a screw diameter of 75 mm to which a hollow plate-shaped die having a thickness of 20 mm and a thickness of 20 mm was attached. The discharged molded body was subjected to wet steam curing at 60 ° C. for 8 hours, and then autoclaved at 160 ° C. under a pressure of 0.6 MPa for 4 hours to obtain a plate-shaped inorganic lightweight molded body. Table 1 shows the evaluation results of the specific gravity, bending strength, incombustibility, length change rate, extrudability and surface properties of this molded product.

(Examples 2 to 18) Molding materials were obtained in the same manner as in Example 1 except that the blending amounts were changed as shown in Tables 1 to 3. From these molding materials, plate-like inorganic lightweight molded articles were obtained in the same manner as in Example 1. The specific gravity, bending strength, nonflammability, impact resistance, length change rate, extrudability and surface properties of these molded articles were evaluated. Tables 1, 2 and 3 show the results.
Are shown together.

[0075]

[Table 1]

[0076]

[Table 2]

[0077]

[Table 3]

(Comparative Examples 1 to 9) A molding material was obtained in the same manner as in Example 1 except that the compounding amounts were changed as shown in Tables 4 and 5. From these molding materials, plate-like inorganic lightweight molded articles were obtained in the same manner as in Example 1. The true specific gravity, bending strength, nonflammability, impact properties, rate of change in length, extrudability, and surface properties of this molded article were evaluated. The results are shown in Tables 4 and 5.

[0079]

[Table 4]

[0080]

[Table 5]

The materials shown as Note 1) to Note 7) in Table 1, Table 2, Table 3, Table 4, and Table 5 are as follows. Note 1) Organic fiber: Cellulosic fiber, PP fiber Note 2) Thermoplastic resin foam: Styrene resin foam particles (expansion ratio 30 times, average particle diameter 500 μm) Note 3) Thermoplastic resin foam: Styrene resin foam Particles (expansion ratio: 30 times, average particle size: 1100 μm) Note 4) Thermoplastic resin foam: acrylonitrile resin expanded particles (Matsumoto Microsphere 80E), expansion ratio: 50 to 60 times, particle size: 30 to 60 μm (Matsumoto Yushi Pharmaceutical Co., Ltd.) Note 5) Thermoplastic resin foam: expanded particles of vinylidene chloride-based resin (Matsumoto Microsphere 30E), expansion ratio 50-60 times, particle size 30-80 μm (Matsumoto Yushi Pharmaceutical Co., Ltd.) Note 6) Inorganic lightweight aggregate: ASB (alumina silicate balloon), particle size 150-300 μm, bulk specific gravity about 0.
4, pressure resistance 13MPa, aluminum oxide component about 30
% By weight (Reball Co., Ltd.). Note 7) Admixture: Aluminum oxide-based admixture

[0082]

As described above, a composition containing an inorganic hydraulic material, a siliceous material, a fibrous material, and a lightweight aggregate, and 1) a specific surface area of 5000 as a siliceous material
Beyond cm ² / g, with less than 8000 cm ² / g, and S
using silica powder having an iO ₂ content of 90% by weight or more,
The molar ratio of CaO / SiO ₂ in the composition is from 0.5 to 1.
And 2) a total of 5% by weight or more and 50% by weight of water-absorbing natural mineral fibers other than asbestos and / or water-absorbing inorganic artificial fibers as the fibrous material.
According to the inorganic hydraulic composition of the present invention that satisfies at least one of the following, it is possible to obtain a light-weight, non-flammable, inorganic, lightweight molded article having extremely excellent dimensional stability and containing no asbestos.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) C04B 14:38 C04B 14:38 C 16:08 16:08 14:16) 14:16) (72) Inventor Shunji Fujisato 2-2-162 Miyako Court Ichibankan F-term (Reference) 2-2-26-606 Tsutodori, Nada-ku, Kobe-shi, Hyogo 2E162 CA01 FA00 FA11 FA14 FA16 FD01 4G012 PA04 PA15 PA18 PA24 PB04 PD01 RA01 4G054 AA01 AA15 AB07 AC04 BD02 BD16

Claims (12)

[Claims] 1. A composition comprising an inorganic hydraulic material, a siliceous material, a fibrous material and a lightweight aggregate, wherein the composition satisfies at least one of the following 1) and 2): Hydraulic composition. 1) exceeds the specific surface area 5000 cm ² / g as siliceous materials, 8000 cm ² / g
And a silica powder having a SiO ₂ content of 90% by weight or more is used, and the molar ratio of CaO / SiO ₂ in the composition is in the range of 0.5 to 1.2. 2) As a fibrous material, a total of 5% by weight or more of natural mineral fibers having a water absorbing property other than asbestos and / or inorganic artificial fibers having a water absorbing property.
0% by weight or less is contained. 2. The water-absorbing natural mineral fiber is at least one fiber selected from the group consisting of wollastonite, sepiolite, and attapulgite, and the water-absorbing inorganic artificial fiber is rock wool.
A composition as described. 3. The lightweight aggregate has an expansion ratio of 10 to 100 times.
3. The foamed thermoplastic resin particles having a particle size of not more than twice.
A composition as described. 4. The thermoplastic resin expanded particles have an average particle size of 10
The composition according to claim 3, having a size of from 1 µm to 1300 µm. 5. The foamed thermoplastic resin particle is at least one foamed particle selected from the group consisting of foamed acrylonitrile-based resin particles, foamed vinylidene chloride-based resin particles, and foamed styrene-based resin particles. Composition. 6. The composition according to claim 5, wherein the expanded thermoplastic resin particles are expanded styrene resin particles. 7. The expansion ratio of the expanded styrene resin particles is 2
The composition according to claim 6, wherein the composition has a size of 0 to 50 times and an average particle size of 300 to 1300 µm. 8. The expansion ratio of the expanded styrene resin particles is 2
7. The composition according to claim 6, wherein the composition has a particle size of 0 to 50 times and an average particle size of 300 to 700 μm. 9. As a lightweight aggregate, in addition to thermoplastic resin foam particles, an average particle diameter of 50 μm or more and 300 μm or less,
4. An inorganic lightweight aggregate containing an aluminum oxide component having a bulk specific gravity of 0.1 to 0.7, a pressure resistance of 8 MPa or more, and a weight of 20 to 50% by weight.
The composition according to any one of claims 1 to 8. 10. The composition according to claim 1, wherein water is added, mixed, molded, and cured to obtain a water content of from 10% to 5% by weight. An inorganic lightweight molded article having a length change rate of 0.01% or less and a specific gravity of 1.1 or less. 11. The composition according to claim 1, wherein water is added, mixed, molded, and then cured in an autoclave. The specific gravity is 1.1 or less, and the flexural strength is obtained. Is 6.5 N / mm ² or more. 12. A method for producing an inorganic lightweight molded article, comprising adding water to the composition according to any one of claims 1 to 9, mixing the mixture, molding the mixture, and curing the mixture in an autoclave.