JPH05229859A - Production of hydraulic inorganic composition - Google Patents

Abstract

PURPOSE:To produce a large amount of a hydraulic inorganic composition having improved flexural strength, moldability and surface smoothness by dispersing given amounts of hemp fibers and a water-soluble polymer substance into water to give a slurry and blending the slurry with the residual hydraulic inorganic substance. CONSTITUTION:0.5-25wt.% hemp fiber such as Manila fiber having 2-40mm average fiber length and thickness of 1.5-20 denier and 0.1-33wt.% water-soluble polymer substance such as methyl cellulose are dispersed into 20-100 pts.wt. water to give a slurry. Then the slurry is blended with 100 pts.wt. hydraulic inorganic substance such as Portland cement to give a mixture. The mixture is optionally blended based on 100 pts.wt. hydraulic inorganic substance in the mixture with <=20 pts.wt. reinforcing fibers such as vinylon having thickness of 0.1-40 denier and 1-15mm length and <=100 pts.wt. inorganic filler such as perlite having 0.03-500mum average particle diameter to produce to objective hydraulic inorganic composition.

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 composition containing hemp fibers as a reinforcing material.

[0002]

2. Description of the Related Art A hydraulic inorganic cured product obtained by curing and curing a molded product obtained from a hydraulic inorganic composition using water and a hydraulic inorganic substance such as cement, mortar or gypsum has long been used as an interior or exterior material. It is suitable for use as a building material.
In the process of producing these hydraulic inorganic cured products,
Asbestos fiber is added to the hydraulic inorganic composition and extruded,
A method of obtaining a high-strength hydraulic inorganic cured product by curing and curing is conventionally known. However, in this method, the problem of carcinogenicity of asbestos fibers is pointed out, and development of alternative means is desired.

Therefore, hemp fibers, which have the property of increasing strength when wet with water, have been used as a substitute for asbestos fibers. Examples of the method using hemp fibers are as follows: 1) Fiber-reinforced cement product comprising a cement matrix to which hemp fibers and inorganic fibers in a specific ratio are added (Japanese Patent Laid-Open No. Sho 5)
5-113659), 2) A method in which a specific amount of siliceous aggregate, pulp fibers and fibrillated hemp fibers are dry-mixed with cement, and then an extrusion aid and water are added and kneaded, followed by extrusion molding. Fair 1-2
No. 42452), and the like have been proposed.

[0004]

However, hemp fiber has 10
Since the length is up to 200 mm, which is longer than other fibers, the dispersibility in the cement matrix is poor, and in the method 1), the composition obtained by dispersing in a large amount of water is suction-filtered, and the resulting mixture is pressed. For example, it can be produced only with a very special molding method with poor productivity, and the dispersibility of hemp fibers deteriorates with a molding method suitable for mass production such as extrusion molding.
The reinforcing effect was small.

Further, in the method 2), the hemp fiber must be cut into a short length in order to fibrillate the fiber, so that a sufficient reinforcing effect cannot be obtained. The object of the present invention is to solve the above-mentioned problems, and to provide a manufacturing method capable of satisfactorily dispersing even long fiber hemp having a large reinforcing effect, having high bending strength, and having excellent moldability and surface smoothness. It is to provide a method for producing a hydraulic inorganic composition capable of producing a body.

[0006]

The hydraulic inorganic substance used in the present invention is not particularly limited as long as it is an inorganic substance which exhibits a hardening property when kneaded with water, and examples thereof include ordinary Portland cement, special Portland cement, and 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. Especially, in terms of strength and water resistance, Portland cement Alumina cement is preferably used.

The hemp fibers used in the present invention refer to hemp and its gin-skin fibers, and the types of hemp used include ramie, linen, cannabis, jute, Manila hemp and sisal hemp.

If the average fiber length of the above-mentioned hemp fibers is less than 2 mm, the reinforcing effect is small, and if it exceeds 40 mm, it becomes difficult to disperse in the hydraulic inorganic composition, and the unevenness of the surface of the finally obtained molded article becomes severe. Therefore, it is limited to 2 to 40 mm, and preferably 5 to 15 mm. If the thickness of the hemp fiber is thinner than 1.5 denier, the dispersibility in the hydraulic inorganic composition is lowered, and if it is thicker than 20 denier, the reinforcing effect is small, so 1.5 to 20 denier is preferable, and more preferable. Is 2 to 10 denier.

The amount of hemp fiber added is 10
When it is less than 0.5 parts by weight, the reinforcing effect is small, and when it exceeds 10 parts by weight, the dispersibility in the hydraulic inorganic composition decreases, and the finally obtained molded article has irregularities on the surface. Since it becomes violent, it is limited to 0.5 to 10 parts by weight, preferably 1 to 5 parts by weight.

The water-soluble polymer substance used in the present invention is
It dissolves in water to give viscosity, enhances the fluidity of the composition obtained from the hydraulic inorganic substance and water to improve the shapeability, and absorbs excess water in the cement hardened product There is no particular limitation as long as it is a polymeric substance that can serve as a binder for filling voids between particles, and examples thereof include cellulose ethers such as methyl cellulose, hydroxymethyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, hydroxypropyl methyl cellulose, polyvinyl alcohol, polyacrylic acid and the like. Be done. If the amount of the water-soluble polymer substance added is less than 0.1 parts by weight with respect to 100 parts by weight of the hydraulic inorganic substance, the fluidity of the composition is lowered and the moldability is lowered. Since the water resistance decreases, it is limited to 0.1 to 10 parts by weight, preferably 0.5 to 3 parts by weight.

If the amount of water used in the present invention is less than 20 parts by weight with respect to 100 parts by weight of the hydraulic inorganic substance, the hardening of the hydraulic inorganic substance will not be sufficient, and the dispersibility of the composition will decrease. If the amount exceeds 100 parts by weight, the mechanical strength of the obtained molded article decreases, so the amount is limited to 20 to 100 parts by weight
It is preferably 25 to 70 parts by weight.

In the present invention, reinforcing fibers other than hemp fibers may be added if necessary. As the reinforcing fiber, any one can be used depending on the performance desired to be imparted to the molded body, for example, vinylon, polyamide, polyester, polypropylene, carbon, aramid, acrylic,
Synthetic fibers such as rayon, glass fibers, potassium titanate, steel, inorganic fibers such as magnesium hydroxide fibers, and pulp can be used. Particularly when synthetic fibers are used, the flexibility is remarkably improved. If the thickness of the reinforcing fiber is too thin, it reaggregates during mixing, fiber balls are easily formed by entanglement, the strength of the obtained molded article is not improved, and if it is too thick or too short, the tensile strength is improved. If the reinforcing effect is small, and if it is too thin or too long, the dispersibility and orientation of the reinforcing fibers deteriorate, so a thickness of 0.1 to 40 denier and a length of 1 to 15 mm are preferred. When the amount of the reinforcing fiber added is more than 20 parts by weight with respect to 100 parts by weight of the hydraulic inorganic substance, the dispersibility of the fiber is deteriorated, so 20 parts by weight or less is preferable.

In the present invention, an inorganic filler may be added if necessary. The inorganic filler is not particularly limited as long as it does not dissolve in water, does not inhibit the hardening 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, ,
Aggregate for cement mortar such as silica sand, river sand, fly ash, silica flower, silica fume, bentonite,
Mixing material for mixed cement such as blast furnace slag, sepiolite,
Examples include wollastonite, natural minerals such as mica, calcium carbonate, and diatomaceous earth. For the purpose of further weight reduction, even if silica balloon, perlite, fly ash balloon, shirasu balloon, glass balloon, inorganic natural foam such as foamed clay, organic foam such as styrene beads, vinylidene chloride balloon are used. Good. These may be used alone or in combination of two or more kinds.

The above-mentioned inorganic filler has an average particle size of 0.03.
When it is less than μm, the strength of the obtained molded article decreases, and when it exceeds 500 μm, the particles of the inorganic filler become difficult to disperse and the impact strength decreases, so 0.03 to 500 is obtained.
μm is preferred. The addition amount of the inorganic filler is preferably 100 parts by weight or less because the strength of the obtained molded article decreases if the amount exceeds 100 parts by weight with respect to 100 parts by weight of the hydraulic inorganic substance.

The method for producing a hydraulic inorganic composition of the present invention comprises a slurry comprising 0.5 to 25% by weight of hemp fiber and 0.1 to 33% by weight of a water-soluble polymer substance dispersed in water in advance, and the composition of the balance. It is characterized by mixing with a thing.

In the present invention, the amount of water preliminarily mixed with the hemp fiber and the water-soluble polymer substance may be all or part of the water used in the present invention. In order to sufficiently disperse hemp fibers and the like, it is preferable to use all of them.

The amount of hemp fibers premixed in the present invention may be all or some of the hemp fibers used in the present invention, but is 0 based on the total amount of the slurry. If it is less than 0.5% by weight, the amount of hemp fiber added later becomes too large, so that the dispersion of hemp fiber in the finally obtained composition is poor, and if it exceeds 25% by weight, the dispersion of hemp fiber in the slurry becomes poor. Since it deteriorates, it is limited to 0.5 to 25% by weight.

In the present invention, as a method of mixing the slurry and the rest of the composition, the amount of the child substance may be the whole amount of the amount of the water-soluble polymer substance used in the present invention. However, if the amount is less than 0.1% by weight with respect to the total amount of the slurry, the hemp fibers in the slurry will precipitate, resulting in poor dispersibility, and if the amount exceeds 33% by weight, the viscosity of the slurry becomes high. Since it becomes difficult to disperse the hemp fibers, it is limited to 0.1 to 33% by weight.

In the present invention, the method of mixing the slurry and the rest of the composition is not particularly limited, and a hydraulic inorganic substance and, if necessary, hemp fiber, water-soluble polymer substance, water, reinforcing fiber, and inorganic substance are sequentially added to the slurry. A filler or the like may be added and mixed, or a composition other than the slurry may be mixed in advance and then mixed with the slurry. The above-mentioned mixing method is not particularly limited, and the slurry and other compositions can be added to a conventionally known mixer or the like and mixed by stirring.

The method for obtaining a molded product from the hydraulic hydraulic inorganic composition obtained by the production method of the present invention is not particularly limited, and it can be molded by a conventionally known method such as extrusion molding, press molding, or casting. it can.

If the obtained molded product is a hydraulic inorganic substance having a high curing rate such as gypsum,
By heating during molding, for example during press molding,
It can be cured at the same time as molding, and the molded body obtained may be naturally cured over time, but when using a hydraulic inorganic substance such as Portland cement, which has a slow curing reaction, Needless to say, the curing reaction can be promoted and the mechanical properties can be improved by performing curing by a conventionally known method such as heating and humidifying the molded body.

[0022]

EXAMPLES The details of the present invention will be described in more detail with reference to Examples. Examples 1 to 8 and Comparative Examples 1 to 7 Hemp fibers 1 (ramie hemp, average fiber length 10 mm, average thickness 4.5 denier) and hemp fibers 2 (ramie hemp, average fiber length) shown in Table 1 25 mm, average thickness 4.5 denier, hemp fiber 3 (ramie, average fiber length 15 mm, average thickness 4.5 denier), hemp fiber 4 (linen linen, average fiber length 10 mm, average thickness 2.0) Denier), (Hemp fiber 5
(Ramie hemp, average fiber length 50mm, average thickness 4.5 denier), hydroxypropyl methylcellulose (20 ° C
The viscosity of a 2% aqueous solution of 30,000 cps) and water were placed in a mixer (trade name; Erich mixer RV02 manufactured by Erich Co.) and mixed at 500 rpm for 3 minutes.

Next, a predetermined amount of ordinary Portland cement (manufactured by Onoda Cement Co., Ltd.) and fly ash (JIS A 6201 equivalent product) shown in Table 1 were added to the obtained mixture.
Kanden Kako Co., Ltd., polypropylene fiber (Daiwa Boseki Co., Ltd.,
Product name: PZL12d), styrene beads (Sekisui Plastics Co., Ltd., product name: Eslen beads HN40), hemp fiber 1,
Hemp fiber 6 (ramie hemp, average fiber length 2 mm, average thickness 4.
5 denier, hydroxypropyl methylcellulose (viscosity of 2% aqueous solution at 20 ° C. is 30,000 cp
s) and water were added and mixed at 500 rpm for 3 minutes. The obtained mixture was supplied to an extruder (Miyazaki Tekko KK, trade name; MV-100), and the thickness was 12 mm and the width was 300.
A flat plate of mm was formed.

The obtained molded product was treated at 60 ° C. and 100% RH.
After curing for 12 hours to obtain a cured product, it was subjected to the following test. Bending strength The obtained cured product was left standing at room temperature for 3 weeks, cut to prepare a test piece, and measured according to the method of JISA 1408. Number of fiber lumps The obtained cured product was cut and the cut surface was visually observed to
The number of hemp fiber lumps having a diameter of 3 mm or more observed per 0 cm was counted. Surface unevenness The surface of the obtained cured product was visually observed, and those having no unevenness were marked with O, and those having severe unevenness were marked with X.

The above results are also shown in Table 2.

[0026]

[Table 1]

[0027]

[Table 2]

[0028]

The method for producing a hydraulic inorganic composition of the present invention is a method for producing a composition comprising a hydraulic inorganic substance, hemp fiber, water, and a water-soluble polymer substance, and at least a part of the hemp fiber. A mixture obtained by previously mixing at least a part of water and a water-soluble polymer substance is mixed with a hydraulic inorganic substance and kneaded, so that hemp fibers are dispersed in water in advance, so that a reinforcing effect is obtained. Even large long fiber hemp can be dispersed well.

Therefore, the composition obtained by the production method of the present invention can be molded without problems by a molding method such as extrusion molding which allows mass production, and a molded article excellent in bending strength, moldability and surface smoothness is obtained. be able to. This molded body is an interior material,
It can be suitably used for building materials such as exterior materials.

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Claims (1)

[Claims] 1. 100 parts by weight of a hydraulic inorganic substance, 0.5 to 10 parts by weight of hemp fibers having an average fiber length of 2 to 40 mm, and 20 to 20 parts of water.
A method for producing a composition comprising 100 parts by weight of a water-soluble polymer substance and 0.1 to 10 parts by weight, wherein 0.5 to 25% by weight of hemp fiber previously dispersed in water, water-soluble polymer substance 0. 1
A method for producing a hydraulic inorganic composition, which comprises mixing the slurry of about 33% by weight and the rest of the composition.