JPH0796508A - Production of extrusion molded object from hydraulic composition - Google Patents

Abstract

PURPOSE:To provide an extrusion molded object excellent in shape retention and surface smoothness and having high strength and high toughness from a hydraulic compsn. containing an asbestos-free reinforcing material. CONSTITUTION:When a hydraulic compsn. containing an asbestos-free reinforcing material is subjected to extrusion molding, a water-soluble cellulose derivative and a water in oil type emulsion (W/O type emulsion) of a water-soluble polymer are added to the hydraulic compsn.

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 an extruded product of a hydraulic composition, more specifically, a wall material for construction,
The present invention relates to a method for producing an extrusion molded body of a hydraulic composition which is useful when applied to the production of roofing materials, flooring materials and the like, pipes, panels and troughs for civil engineering.

[0002]

2. Description of the Related Art Asbestos has been widely used as a reinforcing material for hydraulic inorganic substances such as cement and gypsum. However, recently, asbestos pollution has become a problem, so instead of this asbestos, for example, inorganic fibers such as glass fiber, carbon fiber, rock wool; polyacrylonitrile-based,
Organic synthetic fibers such as polyolefin and polyvinyl alcohol; natural organic fibers such as hemp and wood pulp; mica,
Studies are being conducted to put powders such as talc, chlorite, calcium carbonate, kaolin, clay, and wollastonite into practical use as a reinforcing material.

However, the above-mentioned reinforcing material is
Both of them have a larger diameter than asbestos, and since their water retention and hydrophilicity are small, when extruding a hydraulic composition containing these reinforcing materials, there is a problem that smooth extrusion is difficult to achieve. is there. Such a problem can be solved to some extent by adding a large amount of a cellulose derivative such as methyl cellulose to the hydraulic composition.

However, addition of a large amount of a cellulose derivative not only adversely affects the hydraulic property in the process of extrusion molding and the performance of the extrusion molded product, but also the cellulose derivative is expensive, so that the production cost of the obtained product is high. The problem arises that it will be raised significantly. In order to solve such a problem, for example, JP-A-57-209
Japanese Patent No. 866 discloses a method in which a cementitious material is mixed with methyl cellulose and polyacrylamide and extrusion-molded.

Further, Japanese Patent Application Laid-Open No. 4-144949 discloses that
Disclosed is an asbestos-based cement extrusion admixture comprising a water-soluble or water-dispersible cellulose derivative and a water-soluble or water-dispersible acrylamide polymer. However, any of the acrylamide polymers disclosed in these publications are used by being directly dissolved or dispersed in water. Therefore, when these polymers have a low molecular weight, the dissolution or dispersion in water proceeds uniformly, but when they have a high molecular weight, the dissolution or dispersion in water tends to become non-uniform.

Therefore, when a water-constituting composition containing an asbestos-free reinforcing material containing these polymers is extruded, the functions of the above-mentioned polymers may not be uniformly exerted, and as a result, the extruded article may be retained. The moldability is deteriorated, the surface smoothness is deteriorated, and further the mechanical strength is deteriorated.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems when extrusion-molding a hydraulic composition containing a reinforcing material for asbestos, and to provide a hydraulic composition for asbestos. It can be smoothly extruded, has high strength and high toughness,
An object of the present invention is to provide a method for producing an extruded product of a hydraulic composition, which is excellent in shape retention and surface smoothness.

[0008]

In order to achieve the above-mentioned object, in the present invention, when a hydraulic composition containing a reinforcing material of asbestos is extruded, the hydraulic composition contains: Provided is a method for producing an extruded product of a hydraulic composition, which comprises adding a water-soluble cellulose derivative and a water-in-water emulsion (W / O emulsion) of a water-soluble polymer.

First, the hydraulic composition of the present invention means
The main raw material is a calcareous raw material and a siliceous raw material, which are hydraulic inorganic substances, and a reinforcing agent that replaces asbestos and various admixtures are mixed therein. As the calcareous raw material that constitutes one of the main raw materials, for example, Portland cement,
Mention may be made of plain cement such as alumina cement; mixed cement such as blast furnace cement; special cement such as expanded cement.

Examples of the other siliceous raw materials include crystalline silica such as silica sand and silica stone powder; amorphous silica such as fly ash, silica fume, blast furnace slag and diatomaceous earth. You can The mixing ratio of the calcareous raw material and the siliceous raw material when preparing the main raw material is not particularly limited, but is usually about 0.5 to about 1.2 times the former 1 part by weight. Mixed in the range of.

As a reinforcing material to replace asbestos, for example,
Inorganic fibers such as glass fiber, carbon fiber and rock wool;
Examples thereof include organic synthetic fibers such as polyacrylonitrile-based, polyolefin-based and polyvinyl alcohol-based; organic natural fibers such as hemp and wood pulp; fibrous powders such as wollastonite, potassium titanate and edenite.

Of these reinforcements, wollastonite is the preferred reinforcement. When wollastonite is used as a reinforcing material, it is preferably contained in an amount of 1 to 30 parts by weight, and depending on the purpose, 5 to 20 parts by weight, based on 100 parts by weight of the main raw material. Examples of the admixture to be added to the main raw material include, for example, lubricants such as talc, mica, and chlorite that improve the fluidity (moldability) of the hydraulic composition during extrusion molding; Sepiolite, bentonite, which improves water retention during extrusion
Super water-absorbent resin such as zeolite, acrylic polymer and starch-based; perlite, shirasu balloon, glass balloon, foamed beads of synthetic resin, which make extruded products lightweight.
Can be raised.

In the method of the present invention, when the above-mentioned hydraulic composition is extrusion-molded, a water-soluble cellulose derivative and a W / O type emulsion described below are further added as essential components. First, the water-soluble cellulose derivative is
At the time of extrusion molding, it imparts water retention property to the hydraulic composition and serves to enhance the bonding force between the respective components.

Examples of such water-soluble cellulose derivatives include methylcellulose, hydroxymethylcellulose, hydroxypropylmethylcellulose, hydroxypropylethylmethylcellulose and the like. Each of these may be used alone or in combination of two or more. The addition amount of this cellulose derivative is preferably 0.3 to 3 parts by weight with respect to 100 parts by weight of the main raw material of the hydraulic composition. Particularly preferably, it is set to 0.5 to 1 part by weight with respect to 100 parts by weight of the main raw material.

If the amount added is too small, it may not be possible to impart sufficient water retention to the hydraulic composition.
On the contrary, if the amount is too large, the tendency of adversely affecting the curing of the hydraulic composition and increasing the manufacturing cost increases. The viscosity of a cellulose derivative increases remarkably when it is dissolved in water. Therefore, in order to sufficiently permeate this cellulose derivative to the inside of the hydraulic composition,
It is preferable to use a penetrant together. Examples of such penetrants include salts of polycarboxylic acid polymers which are copolymers of acrylic acid, methacrylic acid, maleic acid or fumaric acid and copolymers with other vinyl compounds, butadiene, isoprene and the like. Mention may be made of sulfonates or carboxylates of aliphatic compounds such as sulfonates of polymers of conjugated diene compounds and sulfonates of copolymers of conjugated diene compounds and carboxylic acids. Particularly, a sulfonate of a conjugated diene-based polymer such as an isoprene-based polymer, which has little influence on the hydration reaction of the hydraulic composition and has a large permeation effect of the cellulose derivative, is suitable.

Next, the W / O type emulsion is one in which a water-soluble polymer described later is usually dispersed in oil as fine particles having a particle size of 1 μm or less. When this emulsion comes into contact with water, the dispersed water-soluble polymer is immediately dissolved in water and phase-inverted into an oil-in-water emulsion (O / W emulsion). Then, the phase inversion emulsion penetrates even into the gaps between various reinforcing materials and admixtures constituting the hydraulic composition, and enhances the binding force between the respective components by the synergistic effect with the water-soluble cellulose derivative. Therefore, by allowing smooth extrusion molding, it contributes to the effect of improving the shape retention and surface smoothness of the extruded body, and further the mechanical strength.

The W / O type emulsion having such a function can be prepared as follows. That is, an aqueous solution of a monomer which becomes a target water-soluble polymer by polymerization is dispersed in an inert hydrophobic organic solvent in the presence of a surfactant, and an oil-soluble radical initiator is used to dissolve the aqueous solution. It can be obtained by proceeding the polymerization reaction of the monomer.

Examples of the hydrophobic organic solvent used at this time include aliphatic hydrocarbons, aromatic hydrocarbons, various vegetable oils and animal oils, and specific examples include paraffin, benzene and toluene. Mineral oil, kerosene, etc. can be mentioned. Further, as the monomer that gives the desired water-soluble polymer, for example, acrylamide, methacrylamide, sodium acrylate, sodium methacrylic acid, or a mixture of two or more of them can be preferably mentioned. In addition to the above water-soluble monomer, other water-soluble monomers such as maleic acid, itaconic acid, vinyl sulfonate, styrene sulfonate, and dimethylamino methacrylate may be used in small amounts.

A stable W / O is used as the surfactant.
A type emulsion can be formed, and when the emulsion is brought into contact with water, it can be easily phase-inverted into an oil-in-water emulsion (O / W type emulsion), and is not particularly limited. Absent.
Examples thereof include sorbitan fatty acid ester, polyoxyethylene alkylphenyl ether, polyoxyethylene polyoxypropylene derivative, and polyester-polyoxyethylene condensate.

Examples of the oil-soluble radical initiator used in the above-mentioned polymerization reaction include azo compounds such as azoisobutyronitrile and organic peroxides such as benzoyl peroxide. Since the water-soluble polymer synthesized in this manner has a higher molecular weight, it improves the shape retention of the extruded product by increasing the binding force between the various reinforcing materials and admixtures described above. Although it is preferable, if the molecular weight is too high, the stability of the emulsion will be deteriorated. Therefore, the molecular weight thereof is preferably set in the range of 1,000,000 to 50,000,000 as the weight average molecular weight. Especially preferably, it is 5,000,000-1,500.
In many cases.

The amount of the water-soluble polymer added is preferably 0.01 to 2 parts by weight with respect to 100 parts by weight of the main raw material of the hydraulic composition. Particularly preferably, it is 0.05 to 0.5 parts by weight with respect to 100 parts by weight of the main raw material. If the amount added is too small, the W / O type emulsion will become O / W.
Good phase retention and surface smoothness of the extruded product are difficult to achieve because there are few phase inversions to the mold emulsion, and conversely, if too much, the molding pressure during press molding increases and stable extrusion is achieved. This is because molding becomes difficult.

In the method of the present invention, first, a main raw material composed of a calcareous raw material and a siliceous raw material, a reinforcing material in place of asbestos, a powder of a water-soluble cellulose derivative, and the above-mentioned various admixtures are used, for example. Mix with an Erich mixer to form a mixture, add an appropriate amount of water thereto, and stir the whole. The amount of water added is 100 parts by weight of the above mixture,
Usually, it is set to 20 to 30 parts by weight.

In this case, it is preferable to add the water-soluble polymer W / O type emulsion in a state in which a predetermined amount thereof is dispersed in the water. At this time, the water-soluble polymer is dissolved in water, and the viscosity of the O / W type emulsion obtained as a result of phase inversion is remarkably increased, making it difficult to uniformly mix the emulsion with the hydraulic composition. In some cases

In such a case, a part of the W / O type emulsion used is thickened with an alkali as a main raw material, for example, an unsaturated carboxylic acid such as acrylic acid, methacrylic acid or maleic acid, and acrylic acid. Acid ester,
It is preferable to replace the emulsion with an alkali-thickening emulsion such as a copolymer with a vinyl monomer such as methacrylic acid ester or maleic acid ester.

[0025] Such treatment facilitates mixing of the emulsion with the hydraulic composition, and the extrusion molded article has improved shape retention and surface smoothness, and at the same time has high strength and high toughness. Because it will be. The hydraulic composition thus prepared is then extruded by, for example, a vacuum extruder. Then, the obtained extruded body is cured and hydrated and cured.

At this time, the extrusion-molded body can be formed into an arbitrary shape such as a plate-like article, a columnar article or a tubular article by changing the die of the extruder to a desired die. Also,
As a curing method, natural curing, steam curing, autoclave curing, or a combination thereof may be adopted depending on the type of the extruded product.

[0027]

Examples of the invention

Example 1 100 parts by weight of a main raw material consisting of 65 parts by weight of Portland cement having an average particle size of 20 μm and 35 parts by weight of silica fine powder having an average particle size of 10 μm, 7.5 parts by weight of wollastonite having an average particle size of 20 μm, and an average 10 parts by weight of talc having a particle size of 5 μm,
1.8 parts by weight of pulp, polypropylene fiber with a fiber length of 6 mm
5 parts by weight and 1 part by weight of Metroses 90SH3000 (trade name, hydroxypropylmethylcellulose powder manufactured by Shin-Etsu Chemical Co., Ltd.) were sufficiently mixed with an Eich-mixer (Model RV-02, manufactured by Nippon Erich Co., Ltd.).

Invertex A was added to the obtained mixed powder.
R-65 (trade name, acrylamide W / O type emulsion manufactured by Toagosei Kagaku Kogyo Co., Ltd.) is used as the main raw material.
Add 0.1 parts by weight of water to 2 parts of the main raw material.
8 parts by weight was added, and the whole was sufficiently kneaded with a kneader. The obtained kneaded product was extrusion-molded by a vacuum extruder to obtain a rectangular rod-shaped extrusion molded product having a side of 1.5 mm.

This extruded body was cut into a sample having a length of 500 mm, used as a sample, and allowed to stand on an edge having a span length of 240 mm, and the amount of deflection at the center of the sample was measured to evaluate the shape retention. The amount of deflection was 1.6 mm. No cracks were observed on the surface of the extruded product, and the surface smoothness was good. The extruded body was naturally cured for a whole day and night, then pre-cured in steam at 70 ° C. for 4 hours, then put in an autoclave and cured in steam at 180 ° C. for 5.5 hours.

The bulk density of the molded body after curing is 1.90 g / cm ³ ,
Bending strength (span length, 100 mm) and Charpy impact value under air-dry condition are 390 kg / cm ² and 3.1 kg-, respectively.
It was cm / cm ² . Comparative Example An extruded body was produced in the same manner as in Example 1 except that the emulsion was not added.

The amount of deflection of the obtained molded product was 3.0 mm. Also, many cracks were observed on the surface, and the surface smoothness was poor. The molded body was cured in the same manner as in Example 1. The bulk density of the molded product after curing is 1.91 g / c.
m ³ , bending strength under air-dry condition (span length, 100m
m) and Charpy impact value are 350kg / cm ² , 2.
It was 7 kg-cm / cm ² .

[0032]

As is apparent from the above description, according to the method of the present invention, a hydraulic composition containing a reinforcing material of asbestos is extruded to have excellent shape retention and surface smoothness, and high Strength·
A highly tough extruded product can be produced. this is,
This is an effect brought about by adding a water-soluble cellulose derivative and a W / O type emulsion of a water-soluble polymer to a hydraulic composition to be extruded. Further, according to the method of the present invention, the amount of the water-soluble cellulose derivative used can be reduced, and the economical effect is large.

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Claims (2)

[Claims] 1. A water-in-oil emulsion of a water-soluble cellulose derivative and a water-soluble polymer in the hydraulic composition when the hydraulic composition containing an asbestos reinforcing material is extruded. A method for producing an extruded product of a hydraulic composition, characterized in that and are added. 2. The method for producing an extruded product of a hydraulic composition according to claim 1, wherein the water-soluble polymer is an acrylamide polymer.