JPS585867B2 - Method for manufacturing glass fiber reinforced magnesium carbonate hardened body - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a glass fiber-reinforced hardened magnesium carbonate body that is lightweight and has high strength.

Regarding magnesium carbonate plates, Japanese Industrial Standards (A-6
701), basic magnesium carbonate (XM
gCO3 ・yMg(OH)2 ・XH20) and asbestos, rock wool, cellulose pulp, and organic synthetic fibers are used as reinforcing fiber materials, and the bulk specific gravity is 0.3 due to paper making.
1.1 specifies board manufacturing within the range.

The manufacturing method of the above magnesium carbonate plate is magnesium hydroxide M
Either carbonate g(OH)2 or add sodium carbonate or ammonium carbonate to magnesium chloride to obtain magnesium orthocarbonate (MgCO3.3H20), and add asbestos rock wool, asbestos rock wool, or
After mixing cellulose pulp and organic synthetic fibers and uniformly dispersing them in the slurry and forming them using a papermaking method, the normal magnesium carbonate is changed to basic magnesium carbonate by heating, and the hardening force that occurs as the crystal changes. This is used to develop strength and create a board.

This board has low solubility in water and has a bulk specific gravity of 1.0.
It is used for the exterior of houses as a lightweight insulation material.

However, when the above-mentioned magnesium carbonate plate is manufactured by a paper-forming method, and is rolled up and laminated using a making roll using a circular screen method, for example, it is pressurized and dehydrated by roll pressure, so it has to be lightweight, for example, with a bulk specific gravity of 0.5 or less. It is difficult to do this, and it requires a certain thickness to be used as a heat insulating material. However, in the above-mentioned circular mesh type, if the thickness is 15 mm or more, cracks tend to occur and production efficiency decreases.

In the extrusion method, the raw material is extruded under pressure in an auger, so in order to obtain the viscosity necessary for extrusion, it is necessary to reduce the amount of water and add a plasticizing material such as methyl cellulose. Mainly hollow panels, the overall bulk specific gravity of the manufactured panels is 0.5
In the following, the bulk specific gravity of the thick portion is 0.8 to 1.0.

On the other hand, as a method for manufacturing a lightweight magnesium carbonate plate with a bulk specific gravity of 0.5 or less, for example, asbestos and pulp are added to a magnesium carbonate slurry, the slurry is swollen by steam injection or heating, and the slurry is poured into a mold.
A method of obtaining molded bodies by pressurized dehydration has been reported, but asbestos is dependent on overseas resources and is restricted as a carcinogen, and large amounts of pulp are used because of the magnesium carbonate obtained. This makes the board unsuitable as a building material in terms of fire resistance and flame retardancy.

Under such objective circumstances, the present inventors have conducted repeated studies to provide a method for producing a lightweight and strong hardened magnesium carbonate body using generally commercially available harmless glass fibers, and as a result, they have developed the present invention. reached.

That is, the gist of the present invention is as follows: (1) 1 to 5% cellulosic pulp and glass fibers with a fiber length of 5 to 40 mm are added to a suspension slurry of magnesium carbonate (MgCO3.3H20) by weight in the product. 2-1
After mixing 0%, the slurry is swollen by steam blowing or heating, poured into a mold, dehydrated under pressure, and then the above normal magnesium carbonate is changed to basic magnesium carbonate by steam blowing or heating. A method for producing a glass fiber-reinforced hardened magnesium carbonate body characterized by: (2) normal magnesium carbonate (MgC03.3 H20
) After mixing 1 to 5% of cellulosic pulp to the suspension slurry based on the weight ratio in the product, the slurry is swollen by steam blowing or heating, and at the same time it is poured into a mold with a fiber length of 10 to 60 vIl. Glass fiber of 2~
A glass fiber characterized in that the above-mentioned normal magnesium carbonate is transformed into basic magnesium carbonate by spraying and mixing into the slurry in a range of 10%, followed by pressure dehydration molding, and then by steam blowing or heating. A method for producing a reinforced hardened magnesium carbonate body.

Since the present invention uses magnesium orthocarbonate as a starting material, it is not necessary to use alkali-resistant glass fibers, and ordinary glass fibers can be used as the glass fibers.

In addition, the first manufacturing method described above is suitable not only for manufacturing flat plates (boards) but also for manufacturing irregularly shaped materials such as cylindrical heat-insulating tubes, and the second manufacturing method is suitable for manufacturing flat plates. .

That is, in the first manufacturing method, the slurry concentration is 10 to 2
To 0% magnesium orthocarbonate suspension slurry, cellulose pulp is added in the range of 1 to 5% by weight in the product, followed by 2 to 10% of relatively short glass fibers with a fiber length of 5 to 40 mm. After mixing thoroughly until uniformly dispersed, the temperature is raised to about 80°C by steam blowing or heating with normal hot air, and a part of the surface of the magnesium orthocarbonate in the slurry turns into basic magnesium carbonate. The entire slurry becomes swollen.

This is poured into a mold and molded under pressure while being dehydrated.

By keeping the obtained molded body at a maximum temperature of 150°C, preferably about 80°C, by blowing steam or heating with ordinary hot air, the normal magnesium carbonate is converted to basic magnesium carbonate, and the hardening that occurs as the crystal changes. This method uses force to develop strength and produces the required glass fiber-reinforced hardened magnesium carbonate body.

In this first manufacturing method, the glass fibers are dispersed by mixing and then poured into a mold.In order to avoid the glass fibers from becoming entangled and clumpy during mixing, relatively short glass fibers such as those described above are used. Glass fibers are used and dispersed through mixing so that the glass fibers have no directionality and are positioned randomly.

Therefore, as described above, this first manufacturing method is suitable for manufacturing not only flat plates but also irregularly shaped materials.

In the following second manufacturing method, cellulose pulp was added to a magnesium orthocarbonate suspension slurry with a slurry concentration of 10 to 20% in a range of 1 to 5 parts according to the weight ratio in the product, and was uniformly dispersed. After that, the slurry is heated to about 80°C by steam blowing or heating with ordinary hot air to swell the slurry as described above, and at the same time pour it into the mold.
roving) is continuously cut by a relatively long 10~
The slurry was sprayed onto the slurry inside the mold while being cut to a length of 60 mm, so that it was uniformly dispersed therein.

The amount of glass fiber sprayed ranges from 2 to 10%.

After spraying, the slurry is dehydrated and pressurized to form a molded body, and the resulting molded body is kept at a maximum temperature of 150°C, preferably about 80°C, by steam blowing or heating with ordinary hot air, thereby producing magnesium orthocarbonate. It is the same as in the case of the first production method that the magnesium carbonate is changed into basic magnesium carbonate, and the strength is developed by the hardening length that occurs with the change of the crystal, and the required glass fiber reinforced magnesium carbonate hardened body is obtained.

This second manufacturing method is a method in which the glass fibers are cut and blown onto the slurry in the mold, and the glass fibers blown from above are mainly oriented two-dimensionally within the slurry, so they are treated as glass fibers. can be relatively long.

Therefore, as described above, this second manufacturing method is suitable for manufacturing flat plates.

In the above first manufacturing method and second manufacturing method,
The slurry concentration of the magnesium orthocarbonate suspension slurry is 10
The slurry concentration is in the range of ~20%, but when the slurry concentration exceeds 20%, the fluidity of the slurry decreases significantly, making it difficult to disperse the glass fibers.

It goes without saying that the cellulosic pulp that is blended contributes to weight reduction and strength development, but it is effective in promoting the dispersion of glass fibers. % range, and the blending amount is 1
If it is less than 5%, the blending effect will be small, and if it exceeds 5%, the fire resistance and flame retardance of the product will be reduced.

The amount of glass fiber as the main reinforcing material is in the range of 2 to 10% by weight in the product.

If the blending amount is less than 2%, the reinforcing effect will be small, and if it exceeds 10%, the dispersibility will deteriorate.

Further, the purpose of swelling the slurry by heating to about 80° C. before molding is to facilitate molding.

As shown in the examples, the cured product produced by the first production method or the second production method has a bulk specific gravity of 0.
5 or less, the strength is on par, the water absorption is extremely low, the fire resistance and flame retardance are excellent, and the cost is advantageous.

Therefore, the glass fiber-reinforced hardened magnesium carbonate body obtained by the present invention is suitable as an interior and exterior building material.

Next, the present invention will be explained in more detail with reference to Examples.

The present invention is not limited to the following examples unless it exceeds the gist thereof.

Example 1 Pulv and glass fiber (E glass) were added to a magnesium orthocarbonate slurry with a slurry concentration of 15% as shown in Table 1. Examples 1 to 4
After mixing and uniformly dispersing the slurry at the compounding ratio shown as below, blowing steam to swell the slurry at about 80°C, pour it into a mold, and mold the slurry by pressure dehydration until it reaches a predetermined thickness. Each was cured and dried at 80°C for 4 hours.

The physical properties of the obtained flat plates (boards) are shown in Table 1.

The raw material formulations and physical properties of the obtained flat plates of Comparative Examples 1 and 2, which were treated in the same manner as in these Examples, are also listed in Table 1.

Example 2 Pulp was mixed and uniformly dispersed in magnesium orthocarbonate slurry with a slurry concentration of 10% in the proportions shown in Examples 5 to 8 in Table 2, and then steam was blown in to swell the slurry at about 80°C. This was poured into a mold, and the glass fibers (E-glass) were cut at the same time while being blown into the slurry in the mold. After mixing, dehydration and pressure molding was performed for 15 minutes, and each molded product was cured and dried at 80°C for 4 hours. , the obtained flat plate (
Table 2 shows the physical properties of each board).

The raw material formulations and physical properties of the obtained flat plates of Comparative Examples 3 and 4, which were treated in the same manner as in these Examples, are also listed in Table 2.

Claims (1)

[Scope of Claims] 1. 1 to 5% cellulosic pulp and 2 to 1% glass fibers with a fiber length of 5 to 40 mm in a suspension slurry of magnesium orthocarbonate (MgC03 .3H20) in the weight composition of the product.
After mixing 0%, the slurry is swollen by steam blowing or heating, poured into a mold, dehydrated under pressure, and then the above normal magnesium carbonate is changed to basic magnesium carbonate by steam blowing or heating. A method for producing a glass fiber reinforced magnesium carbonate hardened body. 2 Orthomagnesium carbonate (MgCO3.3 H20)
After mixing 1 to 5% cellulosic bulb into the suspension slurry based on the weight ratio in the product, the slurry is swollen by steam blowing or heating, and simultaneously poured into a mold to form fibers with a fiber length of 10 to 60 mm. 2 to 10 glass fibers
After spraying and mixing into the slurry in the range of %,
A method for producing a glass fiber-reinforced hardened magnesium carbonate product, which comprises performing pressure dehydration molding and then converting the above-mentioned normal magnesium carbonate into basic magnesium carbonate by steam blowing or heating.