JPH07126057A - Extrusion molded article of hydraulic composition and production thereof - Google Patents

Abstract

PURPOSE:To produce an extrusion molded article comprising a hydrated har dened material containing an asbestos-free reinforcing material, having a dense texture structure, excellent rupture resistance and mechanical strength. CONSTITUTION:In producing a hydraulic composition comprising an asbestos-free reinforcing material-containing hydrated hardened material, having 1.4-2.2 bulk specific gravity and 0.02-0.08cc/g pore volume of 1,000-100,000Angstrom measured by mercury penetration method by extrusion molding the asbestos-free reinforcing material-containing hydraulic composition, the green extrusion molded article is treated with wet heat and treated with dry heat at 150-350 deg.C.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an extruded product of a hydraulic composition containing an asbestos reinforcing material, and a method for producing the extruded product. More specifically, it has excellent explosion resistance and good mechanical properties. TECHNICAL FIELD The present invention relates to a hydraulic inorganic material-based extrusion molded body and a method for producing the same.

[0002]

2. Description of the Related Art Wall materials for construction, roofing materials, flooring materials, pipes for engineering works, panels, troughs, etc. are usually manufactured as an extrusion molded body of an inorganic hydraulic material. This extruded product is suitable for hydraulic inorganic substances such as cement and gypsum.
If necessary, add reinforcing materials and other auxiliary materials that enhance the mechanical properties of the product and water, knead the whole, and extrude the kneaded product into a desired shape with an extruder, then cure and produce. Has been done.

Recently, in order to improve the performance of the extruded product, a method of putting the extruded product's green into an autoclave and curing it under pressure and heating has been widely practiced. The extruded body thus cured is densified and has improved mechanical properties. On the other hand, on the other hand, it has the drawback of being prone to explosion at high temperatures.

Asbestos has been widely used as a reinforcing material for extruded products. However, recently, asbestos pollution has become a problem, and therefore various inorganic or organic fibrous substances have begun to be used as a reinforcing material in place of this asbestos. However, all fibrous substances that replace asbestos have smaller water retention and hydrophilicity than asbestos, so when these are used as reinforcements to produce extruded products, the shape retention of extruded green is reduced. The problem is occurring. In order to avoid such problems and restore the shape retention of the green, the amount of water mixed may be reduced.

However, if the amount of water mixed is reduced, the product finally obtained becomes denser and a new tendency is apt to explode. By the way, JP-A-60-108354 discloses an extruded product obtained by adding an organic natural fiber to a raw material containing cement and asbestos as main components and extruding the mixture, and then curing the green in an autoclave. Also, JP-A-61-86
Japanese Patent No. 480 discloses a method for producing a cement molded product, in which substance particles that are inactive with respect to cement are added to a cement mixture. Furthermore, JP-A-1-122
Japanese Patent Publication No. 951 discloses a cement extrusion molded product which is cured by adding organic synthetic fiber under high temperature and high pressure.

However, although the extrusion-molded article based on the above-mentioned prior art shows some degree of improvement in explosion resistance, the degree is not necessarily sufficient.
Furthermore, there is a possibility that the flame-retardant property and the mechanical property of the extruded product may deteriorate, and there is a problem that the product cannot be a sufficiently satisfactory product. Further, Japanese Patent Laid-Open No. 3-103348 discloses a hardened cement product having a dense tissue structure. However, although this cured product has a high strength, it still has a problem that it is prone to explosion.

[0007]

DISCLOSURE OF THE INVENTION An object of the present invention is to provide an extruded product of a hydraulic composition which is dense, and at the same time is excellent in explosion resistance, flame retardancy and mechanical properties, and its production. Is to provide a method.

[0008]

In order to achieve the above-mentioned object, the inventors of the present invention have conducted extensive studies as to the influence of the structural structure of an extruded product on the explosion resistance and mechanical properties. We obtained the finding that the bulk specific gravity and pore volume of a molded product are important defining factors, and based on this, we have developed the extrusion molded product of the present invention and a method for producing the same.

That is, the extruded product of the hydraulic composition provided by the present invention is composed of a hydrated cured product containing a reinforcing material of asbestos, has a bulk specific gravity of 1.4 to 2.2, and mercury. The pore volume of 1000 to 100000Å measured by the press fitting method is 0.02
Is 0.08 cc / g, and the production method thereof is the same as that of extruded green when an extruded body is produced by extruding a hydraulic composition containing a reinforcing material of asbestos. After heat and moisture curing, the temperature is 150-350 ℃
It is characterized in that it is subjected to dry heat treatment.

First, the extrusion molded body of the present invention has a bulk specific gravity of 1.4 to 2.2. If the bulk specific gravity is less than 1.4, the mechanical structure is not at a satisfactory level because the entire structure of the structure is rough, and if it is more than 2.2, it is excessive. Since it is densified, it is easy to cause an explosion. The preferred bulk specific gravity is 1.6 to 2.0.

The bulk specific gravity referred to in the present invention is calculated based on the following formula: absolute dry weight / saturated water weight / water weight, and the following formula: absolute dry weight / (saturated water weight−water weight). Refers to the value that is given. Further, the extrusion-molded product of the present invention has an integrated value of the volume of pores having a pore diameter in the range of 1000 to 100000Å of 0.02 to 0.08 cc / g when the pore diameter distribution is measured by the mercury porosimetry method. Needs to be in range.

When the pore volume is less than 0.02 cc / g, the water of crystallization which is the cause of the explosion phenomenon is generated to the outside by being formed by the hydration reaction described below and incorporated in the extruded product. Explosion is more likely to occur because it is less likely to dissipate. If it exceeds 0.08 cc / g, the bonding strength between the constituent components of the extruded product will be weakened and the physical properties such as mechanical strength will deteriorate. It is easy to invite. The preferable pore volume is 0.02 to 0.07 cc / g, and more preferably 0.03 to 0.06 cc / g.

The extruded product of the present invention can be manufactured as follows. That is, first, a hydraulic composition containing a reinforcing material of asbestos is extruded to produce a green. In preparing a hydraulic composition to be extruded, a hydraulic inorganic material composed of a calcareous raw material and a siliceous raw material is mixed with a reinforcing material in place of asbestos and various admixtures.

Examples of calcareous raw materials used include plain cements such as Portland cement and alumina cement; mixed cements such as blast furnace cements; special cements such as expansive cements. Examples of the siliceous raw material include crystalline silica such as silica sand and silica powder; non-crystalline silica such as fly ash, silica fume, blast furnace slag, and diatomaceous earth.

At this time, as the siliceous raw material, for example, when a relatively coarse particle having a particle diameter of about 100 to 500 μm is used in combination, an effect of improving the explosion resistance is observed as compared with the case where only the fine particle is used. Therefore, it is preferable. However, if only coarse particles are used, the fluidity at the time of extrusion molding will deteriorate, and the mechanical strength of the extrusion molded product will begin to decline. It is preferable to limit the content to about 80% by weight and to use fine siliceous raw materials for others.

The mixing ratio of the calcareous raw material and the siliceous raw material in this hydraulic inorganic material is not particularly limited, but usually the latter is 0.2 with respect to the weight of the former.
It is preferable to set the ratio to 1.2. As a reinforcing material to replace asbestos, for example, inorganic fibers such as glass fiber, carbon fiber and rock wool; 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;

When pulp is used among these reinforcing materials,
The pulp may be any aggregate of cellulose fibers such as hardwood pulp, softwood pulp, waste paper pulp, hemp and bamboo pulp. The blending amount of this pulp is 0.5 with respect to 100 parts by weight of the above-mentioned hydraulic inorganic material.
~ 5 parts by weight. If the compounding amount is less than 0.5 parts by weight, the effect of improving the explosion resistance of the obtained extrusion molded article becomes small, and if it is more than 5 parts by weight, uniform dispersion in the hydraulic composition does not occur. It tends to be easy to cause deterioration of the mechanical properties of the extruded product. The preferred amount of pulp is 0.7 to 3 with respect to 100 parts by weight of the hydraulic inorganic material.
Parts by weight.

Of the above-mentioned reinforcing materials, wollastonite is a preferable reinforcing material. When wollastonite is used as a reinforcing material, it is set to 1 to 30 parts by weight with respect to 100 parts by weight of the above-mentioned hydraulic inorganic material. This is because if the blending amount is too small, a sufficient reinforcing effect cannot be obtained, and if the blending amount is too large, the molding pressure during extrusion molding remarkably increases, and the surface quality of the obtained extrusion molded product deteriorates. The preferable blending amount is 5 to 20 parts by weight with respect to 100 parts by weight of the hydraulic inorganic material.

When an organic synthetic fiber is used as the reinforcing material, the organic synthetic fiber has a length of 1 to 10 mm,
It is preferably cut into 4 to 6 mm, and these short fibers may be blended alone or in a state of mixing several kinds. The blending amount of the short fibers is 0.3 to 100 parts by weight of the above-mentioned hydraulic inorganic material.
3 parts by weight, preferably 0.5 to 2 parts by weight. This is because if the blending amount is too small, the above-mentioned effects cannot be sufficiently obtained, and if it is too large, it becomes difficult to uniformly disperse it in the hydraulic composition.

Examples of the admixture to be added to the hydraulic inorganic substance include, for example, talc, mica, chlorite, etc., which improve the fluidity (moldability) of the hydraulic composition during extrusion molding. Lubricants: inorganic water retention agents such as sepiolite, bentonite, zeolite, etc. that improve water retention during extrusion, super absorbent polymers such as acrylic polymers and starches; pearlite, which reduces the weight of extrusions Examples thereof include shirasu balloon, glass balloon, and synthetic resin foam beads.

Further, for the purpose of imparting water retention to the hydraulic inorganic substance and other compounding ingredients in the hydraulic composition during kneading or extrusion molding of the respective components, and thus enhancing the binding force between the respective components, for example, It is preferable to add a water-soluble cellulose derivative such as methyl cellulose, hydroxyethyl cellulose, hydroxymethyl cellulose, hydroxypropyl methyl cellulose, hydroxyethyl cellulose, and hydroxypropyl ethyl methyl cellulose.

The content of the water-soluble cellulose derivative at that time is 0.3 to 3 parts by weight, preferably 0.5 to 1.5 parts by weight, based on 100 parts by weight of the hydraulic inorganic material. This is because if the blending amount is too small, the above-mentioned effect cannot be obtained, and if it is too large, the hardening of the hydraulic inorganic substance is hindered and the manufacturing cost becomes high. Furthermore, when blending the above-mentioned water-soluble cellulose derivative, in order to enhance the dispersibility of this cellulose derivative, and to enhance the permeability to the gap between the respective components to sufficiently exert its blending effect, In addition, it permeates sulfonic acid salts of aliphatic polymers, emulsions of acrylic polymers with carboxyl groups in the molecule and alkali thickening, and water-in-oil emulsions of water-soluble polymers. It is preferable to add it as an agent.
This is because the blast resistance of the extruded body is improved by doing so.

In the present invention, predetermined amounts of the above-mentioned hydraulic inorganic substance, reinforcing material and admixture are mixed with, for example, an Erich mixer (manufactured by Eirich Japan Co., Ltd.), and an appropriate amount of water is added thereto. Then, the whole is kneaded to prepare a hydraulic composition. The amount of water to be added is set to 10 to 40 parts by weight, preferably 20 to 30 parts by weight, based on 100 parts by weight of the hydraulic inorganic material.

At this time, it is preferable that the penetrating agent is blended in a state of being previously dispersed or dissolved in water. The hydraulic composition thus prepared is then extrusion-molded using a vacuum extruder to produce a green. The vacuum extruder used is not particularly limited as long as it is a known one, for example,
A two-stage vacuum extruder having a structure in which a degassing vacuum chamber is interposed between the first and second stages is preferable.

At this time, the green can be formed into an arbitrary shape such as a plate-like material, a columnar material, or a cylindrical material by changing the die of the extruder to a desired die. In the present invention, next, the formed green is subjected to heat and moisture curing to cause a hydration reaction between the calcareous raw material and the siliceous raw material to be hydrated and hardened. The conditions of the moist heat treatment are selected so that the obtained hydrated cured product has a bulk specific gravity of 1.4 to 2.2, preferably 1.6 to 1.9. This is because an extrusion-molded product having a bulk specific gravity outside the above range tends to have a smaller effect of improving explosion resistance and mechanical properties.

Specifically, the green of the obtained extruded product is pre-cured in steam at a temperature of 50 to 100 ° C., and then autoclaved in steam at a temperature of 140 to 200 ° C. As the autoclave, a known one for curing a cement molded product may be used. Further, the time required for curing varies depending on the curing temperature, but is usually set to 3 to 15 hours.

The moist heat treatment may be stopped during the above-mentioned pre-curing, or may be continued until autoclave curing. Then, in the present invention, a dry heat treatment is performed subsequent to the above-mentioned wet heat treatment. This dry heat treatment controls the amount of water that is generated by the hydration reaction during the wet heat treatment and is taken as water of crystallization in the hydrated cured product, and thereby the above-mentioned pore volume in the extruded body is controlled. 0.02
It is carried out in order to further improve the explosion resistance by adjusting to the range of 0.08 cc / g.

Specifically, the extruded body (hydrated cured product) which has been subjected to the wet heat treatment is subjected to a dry heat treatment at a temperature of 150 to 350 ° C. If this temperature is lower than 150 ° C, the effect of removing water of crystallization contained in the extruded product is small, and the pore volume of pores with a pore diameter of 1000 to 100000Å is 0.02 cc / g.
It becomes smaller, the effect of improving explosion resistance decreases, and also
When dry heat treatment is performed at a temperature higher than 350 ° C., the pore volume of the extruded product becomes too large, and the mechanical properties such as bending strength and impact resistance of the extruded product decrease as a whole. . The preferred temperature is 170-300 ° C.

This dry heat treatment may be carried out using a known batch type, multistage type or continuous type dry heat treatment apparatus. As the heating means, hot air type, infrared or high frequency heating type, microwave heating type, or the like can be used. For example, when the hot air heating means is used, the temperature raising and lowering conditions are as gentle as possible, specifically, the temperature raising rate is 1
It is preferable to carry out at -4 ° C / min and at a cooling rate of 0.5-1.5 ° C / min. Further, the holding time at a predetermined curing temperature is preferably about 0.5 to 2 hours.

In order to enhance the effect of this dry heat treatment, the thickness of the solid part of the extruded body after the wet heat treatment is 10 to 10.
It is preferably 20 mm. This thickness is 10 mm
When the thickness is thinner, the effect of dry heat treatment is excessively expressed, resulting in deterioration of properties such as the extruded body after the treatment. When the thickness is thicker than 20 mm, the effect of dry heat treatment is solid. This is because it does not easily reach the vicinity. The thickness of the solid portion is preferably 11 to 19 mm, more preferably 12 to 18 mm.

With respect to the extruded product thus produced which is excellent in explosion resistance, the apparent thermal conductivity of the whole is set to a target value although it depends on the thickness of the solid part. It can be controlled to further improve the explosion resistance. As a means therefor, it is preferable that a part or the whole of the extruded body has a water absorption of 2 to 10% by weight.

The water absorption rate (%) as used herein means 100 × (water absorption weight−excess dry weight) / excess dry weight. When the water absorption is less than 2% by weight, the effect of controlling the thermal conductivity of the extruded product does not appear so much, and when it is more than 10% by weight, the explosion resistance is lowered.

The above-mentioned water absorption is imparted by, for example, immersing the entire extruded body in water for a predetermined time, or spraying water into a spray or shower shape and spraying it on the necessary parts of the extruded body. You can

[0034]

Examples of the invention 65 parts by weight of Portland cement, 35 parts by weight of silica sand having a particle size of 2 to 600 μm, 1.3 parts by weight of pulp, 7.5 parts by weight of wollastonite, 10 parts by weight of talc, polypropylene having a fiber length of 6 mm 0.3 parts by weight of fiber, and Metroses 90SH-30000 (trade name, hydroxypropylmethylcellulose powder manufactured by Shin-Etsu Chemical Co., Ltd.)
1 part by weight was thoroughly mixed with an Erich mixer (model RV-02 manufactured by Nippon Erich Co., Ltd.).

Here, Dynaflo-Z105 (trade name,
0.25 part by weight of water in which sodium polyisoprene sulfonate manufactured by Japan Synthetic Rubber Co., Ltd. is dispersed in the total amount of Portland cement and silica sand is 2
6 parts by weight was added, and the whole was sufficiently kneaded with a kneader. This kneaded product was extrusion-molded by a two-stage vacuum extrusion molding machine in which a deaeration vacuum chamber was interposed, to obtain a green extruded product having a rectangular rod shape with a side of 15 mm.

Then, the green is naturally cured for a whole day and night, and then pre-cured in steam at 70 ° C. for 4 hours,
Subsequently, autoclave curing was carried out in steam at 180 ° C. for 5.5 hours. The bulk specific gravity of the extruded product after curing under heat and humidity is 1.8, and the bending strength in the air-dry state (span length, 10c
m) is 346 kg / cm ² , Charpy impact value is 2.05 kg · cm /
It was cm ² .

The extruded body after wet heat curing was
After drying at ℃ for 2 hours, from 105 ℃ to 250 ℃.
The mixture was gradually heated for 5 hours, kept at 250 ° C. for 0.5 hour for dry heat treatment, and then gradually cooled to room temperature for 8 hours. The bulk density of the obtained extrusion-molded product was 1.78, and the pore volume of the pore size of 1000 to 100000Å measured by the mercury penetration method was 0.041 cc / g.

The flexural strength was kept at 96% of the flexural strength of the extruded product after the wet heat treatment. Next, the extruded body after the dry heat treatment was heated to 700 ° C. at a temperature rising rate of 70 ° C./min, held at that temperature for 15 minutes, and then gradually cooled to room temperature to evaluate fire resistance.

Although some cracks were found on the surface,
The extruded body remained in its original shape and no explosion occurred. Comparative Example An extruded body was produced in the same manner as in the example, except that the wet heat treatment was stopped without performing the dry heat treatment.

The bulk specific gravity of this extruded product was 1.82,
The volume of pores having a pore diameter of 1,000 to 100,000Å measured by mercury porosimetry was 0.015 cc / g. The bending strength (span length, 10 cm) was 342 kg / cm ² , and the Charpy impact value was 2.03 kg · cm / cm ² . This extruded body was subjected to the fire resistance evaluation test shown in the examples. Explosion occurred 3 minutes after the start of heating, and it collapsed before the original shape could be stopped.

[0041]

As is clear from the above description, according to the method of the present invention, an extruded hydrated product having a dense structure and having both excellent explosion resistance and mechanical strength is extruded. A molded body can be obtained. This is because the green water extruded from the hydraulic composition was subjected to a wet heat treatment and then a dry heat treatment at a temperature of 150 to 350 ° C. during the production of this extrusion-molded product. The volume specific gravity is controlled to 1.4 to 2.2, and the pore volume of 1000 to 100000Å is controlled to 0.02 to 0.08.
This is the effect brought about by adjusting to cc / g.

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Claims (3)

[Claims] 1. A hydrated cured product containing an asbestos-free reinforcing material, having a bulk specific gravity of 1.4 to 2.2 and a pore volume of 1,000 to 100,000Å measured by mercury porosimetry of 0.02. ~ 0.
The extrusion-molded product of the hydraulic composition, wherein the extrusion-molded product is 08 cc / g. 2. The water absorption is in the range of 2 to 10% by weight,
An extruded product of the hydraulic composition according to claim 1. 3. When an extruded green is extruded from a hydraulic composition containing a reinforcing material of asbestos to produce an extruded product, the extruded green is cured at a temperature of 150 to 350.
A method for producing an extruded product of a hydraulic composition, which comprises performing a dry heat treatment at ℃.