JP5596933B2 - Method for producing gypsum-based molded body - Google Patents

Description

The present invention relates to a method for producing a plaster-base molded article.

  In a gypsum-based molded body obtained by hydrating hydratable gypsum, dihydrate gypsum forming a matrix contains a large amount of crystal water. In such a gypsum-based molded body, when heated to 100 to 200 ° C., the crystal water is released and released, so that the temperature rise is suppressed and the fire resistance performance is excellent. Widely used as interior building material. In addition, when using a gypsum-type molded object as a self-supporting wall material, since it is suitable if the rib is provided (for example, refer patent document 1 etc. below), it is an extrusion molding method (for example patent document 2 below). Etc.) in many cases. On the other hand, when a plate-like gypsum-based molded body is manufactured, it is often manufactured by a papermaking method (for example, see Patent Document 3 below). A gypsum-based molded body produced by such an extrusion molding or papermaking method does not require front and back paper such as gypsum plasterboard, which is a typical gypsum-based molded body, so it is even more than gypsum plasterboard. Excellent fire resistance.

Japanese Patent Laid-Open No. 10-205022 JP-A-1-051359 Japanese Patent Laid-Open No. 60-042267 JP-A-1-224252 JP-A-6-001645 JP 2007-303953 A

  By the way, in the gypsum-based molded body as described above, when the crystal water is detached at a temperature of 100 to 200 ° C., the temperature rises rapidly. It is considered to further improve the fire resistance by further containing a compound that causes a withdrawal reaction.

  For this reason, for example, although it is conceivable that aluminum hydroxide that causes a detachment reaction of crystal water at a temperature of 200 to 230 ° C. is further mixed with the gypsum-based molded body, the crystallization water release temperature of aluminum hydroxide is two water. Since it is close to the separation temperature of gypsum crystal water, it has been difficult to sufficiently improve the fire resistance.

For this reason, the present invention aims to provide a method of manufacturing a gypsum-based molded body can be further improved fire performance sufficiently.

For solving the problems described before mentioned method for manufacturing a gypsum-based molded body according to the present invention, the gypsum as a matrix, fibers from 0.8 to 9.8 wt%, 56.2 to 85 wt% of colemanite containing And a method for producing a gypsum-based molded article formed by an extrusion molding method, comprising 10 to 35% by mass of hydrated gypsum, 1 to 10% by mass of fibers, and 60 to 86.2% by mass of colemanite. A thickening agent and water are added to the solid raw material to be kneaded to form a kneaded product, and the kneaded product is molded by an extrusion method and then cured and cured.

  The method for producing a gypsum-based molded body according to the present invention is the above-described method for producing a gypsum-based molded body, wherein the solid raw material is a filler so that the total amount with the colemanite is 86.2% by mass or less. It is characterized by including.

According to the method of manufacturing gypsum-based molded body according to the present invention, the colemanite 8.5 to 85 mass% (more preferably 20 to 85 wt%) because it contains crystals of dihydrate gypsum forming the matrix Since the crystal water can be further released even in a temperature range (400 ° C.) higher than the water release temperature (100 to 200 ° C.) and the aluminum hydroxide crystallization water release temperature (200 to 230 ° C.), Further improvement can be sufficiently achieved, and it can be suitably used as an interior building material such as a high-performance fireproof partition wall. Furthermore, when the unit colemanite amount U _C contained per 1 mm ² per 1 m ² area is 145 g or more and the thickness is 3 mm or more, the neutron shielding performance can be improved. If it is used as an interior building material in a semiconductor manufacturing factory or a computer room, it is possible to prevent the generation of defective semiconductor products due to neutrons falling from space into the ground and the malfunction of computers.

It is a chart showing the differential thermal analysis (TG-DTA) result of the test body 3 in the confirmation test B performed in order to confirm the effect of the gypsum-type molded object which concerns on this invention, and its manufacturing method. It is a chart showing the differential thermal analysis (TG-DTA) result of the test body 4 in the confirmation test B performed in order to confirm the effect of the gypsum-type molded object which concerns on this invention, and its manufacturing method. It is a chart showing the differential thermal analysis (TG-DTA) result of the test body 6 in the confirmation test B performed in order to confirm the effect of the gypsum-type molded object which concerns on this invention, and its manufacturing method. It is a chart showing the differential thermal analysis (TG-DTA) result of the test body 8 in the confirmation test B performed in order to confirm the effect of the gypsum-type molded object which concerns on this invention, and its manufacturing method. It is a chart showing the differential thermal analysis (TG-DTA) result of the comparison body 1 in the confirmation test B performed in order to confirm the effect of the gypsum-type molded object which concerns on this invention, and its manufacturing method.

  Embodiments of a gypsum-based molded body and a method for producing the same according to the present invention will be described below, but the present invention is not limited only to the embodiments described below.

  The gypsum-based molded body according to the present embodiment contains 0.8 to 9.8% by mass of fiber and 8.5 to 85% by mass (more preferably 20 to 85% by mass) of fiber with gypsum as a matrix. It is.

  Examples of the gypsum include hydrated gypsum such as type II anhydrous gypsum, α-hemihydrate gypsum, β-hemihydrate gypsum, and the like. A matrix is formed as gypsum.

  The above fiber is a molding aid during molding, and plays a role of reinforcement after molding. Cellulose pulp is essential, and glass fiber, carbon fiber, glass wool, rock wool, ceramic wool, etc. Reinforcing fibers such as inorganic fibers and synthetic fibers such as polyamide, polypropylene, polyvinyl alcohol (vinylon), polyester, polyethylene, and acrylic can be used in place of part of the cellulose pulp.

  The fiber needs to have a content of 0.8 to 9.8% by mass. This is because if the fiber content is less than 0.8% by mass, it will be difficult to reinforce sufficiently, whereas if the fiber content exceeds 9.8% by mass, This is because the dispersion of the fibers is likely to be uneven and not only the homogeneity and the surface smoothness are lowered, but also the nonflammability performance is likely to be lowered.

  At this time, it is necessary that the content of the cellulose pulp does not become less than 0.8% by mass and that the total content of the cellulose pulp and the reinforcing fiber does not exceed 9.8% by mass. . The length of the reinforcing fiber is preferably 10 mm or less (preferably 6 mm or less), and the content thereof is preferably 2.8% by mass or less.

  In addition, the cellulose pulp is preliminarily pulverized by a wet or dry general-purpose pulverizer or fibrillator such as a pulper, a disc refiner, a corn type refiner, a disintegrator, and a hammer mill as necessary. And preferred. The beating degree is preferably in the range of 700 to 50 ml in Canadian Standard Freeness (CSF).

The colemanite (2CaO.3B ₂ O ₃ .5H ₂ O), which is a kind of calcium borate mineral, needs to have a content of 8.5 to 85% by mass (more preferably 20 to 85% by mass). . Because, if the content of colemanite is less than 8.5% by mass, it becomes difficult to sufficiently improve the fire resistance, and if the content of colemanite exceeds 85% by mass, the strength is lowered. Because it becomes easy.

  In addition, the above-mentioned gypsum-based molded body may be made of powder or clay such as limestone (calcium carbonate), silica, slag, fly ash, dihydrate gypsum, mica, wollastonite, pearlite, vermiculite, shirasu. It is also possible to include a filler such as a lightweight material such as a balloon or a pulverized product (scrap) of a product waste material in place of a part of the colemanite.

  At this time, it is necessary that the content of the colemanite does not become less than 8.5% by mass and the total content of the colemanite and the filler does not exceed 85% by mass. In addition, it is preferable that content of the said filler is 20 mass% or less.

  The method for producing a gypsum-based molded body according to this embodiment for manufacturing such a gypsum-based molded body includes 10 to 89% by mass (more preferably 10 to 75.6% by mass) of hydratable gypsum and 1 to 1 fiber. Solid material containing 10% by mass and colemanite 10-86.2% by mass (more preferably 23.3-86.2% by mass) is added with water, mixed, molded, cured and cured. I will let you.

  Here, when using the above-mentioned type II anhydrous gypsum as the hydrating gypsum, it is preferable to apply a reaction rate adjusting agent (curing accelerator) that promotes the hydration reaction because the hydration reaction rate is slow. . On the other hand, when α-hemihydrate gypsum or β-hemihydrate gypsum is used as the hydratable gypsum, the reaction rate adjusting agent (setting retarder) delays the hydration reaction because the hydration reaction rate is high. ) Is preferred.

Examples of the curing accelerator include sulfates such as Na ₂ SO ₄ and K ₂ SO ₄ , alums such as KAl (SO ₄ ) ₂ · 12H ₂ O, chlorides such as NaCl and CaCl ₂ , Na Examples thereof include known salts such as carbonates such as ₂ CO _{3 and} nitrates such as NaNO ₃ and NH ₄ NO ₃ , and these can be used alone or in combination.

  As said hardening retarder, well-known things, such as carboxylic acid (a salt is included), an amino acid (a salt is included), protein (a modified body is included), etc. can be mentioned, These can be utilized individually or in combination.

  When the reaction rate adjusting agent is used in a ratio (external ratio) of 0.005 to 3.0% by mass (preferably 0.01 to 2.0% by mass) with respect to 100% by mass of the hydratable gypsum. preferable.

  In addition, when manufacturing by extrusion molding, as an auxiliary | assistant for performing extrusion molding, the ratio (0.2-2.0 mass%) of a thickener with respect to a solid raw material (except reaction rate regulator) ( It is preferable to add it in the “Outside Discount”.

  Examples of the thickener include water-soluble polymer agents such as ethylene oxide polymer, acrylamide polymer, polyvinyl alcohol, methyl cellulose, hydroxyethyl cellulose and the like.

  Moreover, the mixing amount of the said fiber needs to be 1-10 mass%. This is because if the mixing amount of the fibers is less than 1% by mass, it becomes difficult to sufficiently reinforce the molded body. On the other hand, if the mixing amount of the fibers exceeds 10% by mass, This is because the fibers are difficult to disperse sufficiently, and not only the uniformity and surface smoothness of the molded body are lowered, but also the nonflammability performance is liable to be lowered.

  Here, it is also possible to replace a part of the fiber (cellulose pulp) with the reinforcing fiber as necessary and to mix them. At this time, it is necessary that the mixing amount of the cellulose pulp does not become less than the lower limit value and that the total mixing amount of the cellulose pulp and the reinforcing fiber does not exceed the upper limit value. The mixing amount of the reinforcing fibers is preferably 3% by mass or less.

  The amount of the colemanite mixed needs to be 10 to 86.2% by mass (more preferably 23.3 to 86.2% by mass). This is because when the content of colemanite is less than 10% by mass, it becomes difficult to sufficiently improve the fire resistance in the molded body. When the content of colemanite exceeds 86.2% by mass, molding is performed. This is because it tends to cause a decrease in the strength of the body.

  Here, a part of the colemanite may be mixed with the filler as necessary. At this time, it is necessary that the mixing amount of the colemanite does not become less than the lower limit value and that the total mixing amount of the colemanite and the filler does not exceed the upper limit value. The mixing amount of the filler is preferably 20% by mass or less.

  Using such various raw materials, the above-described gypsum-based molded body can be produced by various methods such as an extrusion molding method, a papermaking method, and a mold press molding method.

  Specifically, for example, in the case of producing by an extrusion molding method, the solid raw material and the thickener are introduced into a mixer such as an Eirich type mixer and mixed uniformly by high-speed stirring. Then, after adding water (kneading water) at a ratio (external ratio) of about 25% by mass to the solid raw material, the mixture is further uniformly mixed to obtain a mixture, and then the mixture is mixed with a mixer such as a double-arm kneader. And then kneaded uniformly to obtain a kneaded product. In addition, when adding a reaction rate regulator, it is also possible to mix with the said water (kneading water) previously, and to add to the said solid raw material with the said water (kneading water).

  Then, the kneaded product is extruded by an extrusion molding machine such as a screw type vacuum extrusion molding machine to obtain an uncured molded body, and then the uncured molded body is cured and cured to obtain a gypsum system. A molded body can be obtained.

  Also, for example, in the case of manufacturing by a papermaking method, the solid raw material is introduced into a mixing device such as a pulper, and water is added so that the concentration of the solid raw material is about 3 to 10% by mass. After manufacturing the raw material slurry, the slurry is made by a paper machine, wound up to a predetermined thickness on a making roll of the paper machine to obtain an uncured molded body, and then the uncured molded body is required. Correspondingly, after pressing with a press machine and curing and curing, a gypsum-based molded body can be obtained.

  In addition, when manufacturing by such a papermaking method, it is preferable to make the said fiber 3 mass% or more because papermaking properties can be improved. Moreover, when adding a reaction rate regulator, it is also possible to mix with the said water beforehand and to add to the said solid raw material with the said water.

  The above curing is carried out in a temperature range of 0 to 22 ° C., for example, when a type II anhydrous gypsum is used as a hydrating gypsum (see, for example, Patent Document 3 above), When hemihydrate gypsum such as α-hemihydrate gypsum and β-hemihydrate gypsum is used, for example, it is carried out by ordinary curing indoors. By such curing, the hydratable gypsum reacts with water to form dihydrate gypsum, forms a matrix and hardens.

  In addition, the reaction rate (dihydration rate) to dihydrate gypsum at the time when curing is completed is in the range of about 55 to 85% in terms of molar ratio in the case of type II anhydrous gypsum. Almost 100%, most of them react with dihydrate gypsum, and very little hemihydrate gypsum remains unreacted.

The molded body thus cured and hardened is dried, processed (polished, cut, etc.), etc. as necessary to obtain a gypsum-based molded body having an apparent density of about 1.6 to 1.7 g / cm ^3. Can be manufactured.

  Since the gypsum-based molded body thus produced contains 8.5 to 85 mass% (more preferably 20 to 85 mass%) of colemanite, the desorption temperature of crystal water of dihydrate gypsum (100 ˜200 ° C.) and crystallization water can be further released even in a temperature range (400 ° C.) higher than the crystallization water release temperature of aluminum hydroxide (200 ° C. to 230 ° C.). And can be suitably used as an interior building material such as a high-performance fireproof partition wall.

Moreover, since the unit colemanite amount U _C contained per 1 mm ² per 1 m ² area is 145 g or more and the thickness is 3 mm or more, the neutron shielding performance can be improved. For example, if it is used as an interior building material in a semiconductor manufacturing factory, a computer room, etc., it is possible to prevent the generation of defective products due to neutrons in semiconductor products and the malfunction of computers due to neutrons.

  Furthermore, since colemanite has antibacterial, antifungal and antialgal properties, it can be suitably used as a building material where antibacterial, antifungal and antialgal properties are required.

  Note that the shape of the gypsum-based molded body is not particularly limited, and the present invention is applicable to not only a flat plate shape but also a shape having a rib portion, for example. Can do.

  Further, in the above-described embodiment, the case of manufacturing by an extrusion molding method or a papermaking method has been described. However, the present invention is not limited to this, and other known methods such as a pressure dehydration method by a mold press molding method, for example. It can also be manufactured by this method.

  By the way, the fiber, the colemanite, and the filler have different numerical values in the content ratio range in the gypsum-based molded product and the mixing ratio range in production. This is because the hydrating gypsum is water. This is because it reacts with the dihydrate to change the molecular weight per mole of the gypsum.

  In order to confirm the effects of the gypsum-based molded article and the production method thereof according to the present invention, the following confirmation test was performed.

[Preparation of specimen]
The raw materials shown in Table 1 below are put into an Eirich mixer at the ratios shown in Tables 2 and 3 below and dry-mixed at high speed (for 1 minute), and then wet-mixed at low speed while adding kneading water ( 5 minutes), and then the mixture was put into a double-arm kneader and kneaded (10 minutes) to obtain kneaded materials 1 to 5 in which the raw materials were uniformly dispersed. Next, the kneaded materials 1 to 5 are put into a screw type vacuum extrusion molding machine, extruded into a plate having a thickness shown in Table 4 below (width 600 mm, length 1820 mm), and cured (10 After curing with a jet dryer (nozzle blowing at 130 ° C. for 20 minutes), the test specimens 1A, 1B, 2, 3A, 3B in the ratios shown in Table 4 below are cured. , 4A, 4B, 5A, 5B were prepared. For comparison, a kneaded material α shown in Tables 1 to 3 below was prepared, and a comparative body α having a ratio shown in Table 4 below was also prepared.

[Confirmation test A]
The test specimens 1A, 1B, 2, 3A, 3B, 4A, 4B, 5A, and 5B thus prepared and the gypsum of the comparative body α were determined for the hydration rate, apparent density, and bending strength, respectively. The results are shown in Table 5 below. In addition, the hydration rate of gypsum is obtained by pulverizing the test specimen and the comparative specimen and drying the specimen until it reaches constant temperature (45 ° C.), measuring the mass, calcining (200 ° C.), measuring the mass, and reducing the mass. Based on the amount of gypsum mixed, the apparent density is measured from the mass and volume of the test body and the comparative body measured constant mass in the dryer (40 ℃), The bending strength was measured by applying a No. 3 test piece (dimension: 400 mm × 500 mm) in accordance with “10.3.2” defined in Japanese Industrial Standard (JIS) “A 5430” (span. : 400 mm).

  As can be seen from Table 5 above, the specimens 1A, 1B, 2, 3A, 3B, 4A, 4B, 5A, and 5B (containing the colemanite) are compared with the comparative body α (containing the calcium carbonate: conventional product). It was confirmed that the hydration rate was reduced by about 10% and the apparent density was reduced as the content of colemanite was increased, while almost the same bending strength could be expressed.

[Verification test B]
Differential thermal analysis (TG-DTA) of the test bodies 2, 3A, 4A, 5A and the comparative body α was performed. The results are shown in FIGS.

  As can be seen from FIGS. 1 to 5, the comparative body α (calcium carbonate-containing product: conventional product / FIG. 5) only causes the dehydration reaction of gypsum in the temperature range of 100 to 200 ° C., whereas the test sample 2 , 3A, 4A, 5A (containing colemanite / FIGS. 1 to 4) cause gypsum dehydration reaction in the temperature range of 100 to 200 ° C. and endothermic reaction in the temperature range of 300 to 400 ° C. in two stages. Absorbed heat was observed. Therefore, it was confirmed that the gypsum-type molded object which concerns on this invention can improve fireproof performance.

[Confirmation test C]
Thermal neutron shielding performance tests were conducted on the specimens 1A, 1B, 2, 3A, 3B, 4A, 4B, 5A, 5B and the comparative body α. The results are shown in Table 6 below. In addition, the thermal neutron shielding performance test uses the prompt γ-ray analyzer in the neutron beam experimental facility of the research nuclear reactor “JPR-3M” of the Japan Atomic Energy Agency. After measuring the count value (C _B ) of thermal neutrons passing per unit time, the test specimens 1A, 1B, 2, 3A, 3B, 4A, 4B, 5A, 5B, and the comparative body α are set. The count value (C _S ) of thermal neutrons per unit time was measured, and the thermal neutron shielding rate N _C was determined based on the following equation (1). The amount of unit colemanite U _C contained per 1 mm thickness per 1 m ² area is also shown in Table 6.

N _C (%) = 100− (C _S / C _B ) × 100 (1)

  As can be seen from Table 6 above, the comparative body α (no colemanite: conventional product) allows the thermal neutrons to pass through almost without shielding, whereas the test bodies 1A, 1B, 2, 3A, 3B, 4A, 4B, 5A, 5B (containing colemanite) can shield 60% or more of thermal neutrons without transmitting, and in particular, the test bodies 2, 3A, 3B, 4A, 4B, 5A, 5B It was confirmed that 90% or more can be shielded without transmitting, which is very preferable.

Since the gypsum-based molded body and the method for producing the same according to the present invention can sufficiently improve the fire resistance, it can be suitably used as an interior building material such as a high-performance fire-resistant partition wall. Since the shielding performance can be improved, it is suitable as an interior building material for a semiconductor manufacturing factory, a computer room, etc., and can be used extremely beneficially industrially.

Claims (2)

A method for producing a gypsum-based molded article containing 0.8 to 9.8% by mass of fibers and 56.2 to 85% by mass of colemanite using gypsum as a matrix, and molded by an extrusion method ,
Thickener and water are added to a solid raw material containing 10 to 35% by mass of hydrating gypsum, 1 to 10% by mass of fibers, and 60 to 86.2% by mass of colemanite, and kneaded to obtain a kneaded product. A method for producing a gypsum-based molded article, wherein the kneaded product is molded by an extrusion molding method and then cured and cured. In the manufacturing method of the gypsum type molded object according to claim 1 ,
The method for producing a gypsum-based molded body, wherein the solid raw material contains a filler so that the total amount with the colemanite is 86.2% by mass or less.

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