JPH08259302A - Production of inorganic plate - Google Patents

Abstract

PURPOSE: To obtain an inorganic plate of uniform thickness by spraying a mixture of a cement-based inorganic powder, a specific reinforcing material and an alkali metal silicate on a mold plate to form a mat and pressing the mat, and heating it jetting steam. CONSTITUTION: (A) 40-70 pts.wt. of a cement inorganic powder, (B) 15-35 pts.wt. of a reinforcing material as a mixture of a bamboo reinforcing material 15-40mm long, 2-5mm wide, 10-80 aspect ratio and a wood reinforcing material 0.5-2.0mm wide, 1-20mm long, 20-30 aspect ratio at a weight ratio of 100/0-20/80 and (C) 2-15 pts.wt., per 100 pts.wt. of the cement powder (A), of an alkali metal, silicate are mixed and its moisture content is adjusted to 40-60wt.% to give a forming material. This forming material is sprayed on the mold 1 coated with a mold releasing agent to form a mat 12. The mat 12 is pressed with a movable platen 18, while steam is jetted from the nozzle pipe 26 to effect the primary curing, then aged in the moisture-containing state to effect the final setting.

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 cement-based inorganic plate mainly used for construction.

[0002]

BACKGROUND OF THE INVENTION Conventionally, an inorganic board prepared by mixing a wood reinforcing material such as wood chips, wood wool and wood pulp with cement has been provided as a building board such as an outer wall material and an inner wall material. As a method for producing the above-mentioned inorganic board, recently, a wood-reinforced material is mixed with a cement-based inorganic powder such as cement to form a mat by spraying a molding material on the template, and the mat is heat-pressed to perform primary curing. A dry method in which a cured product is manufactured and then finally cured by demolding and curing the primary cured product is used. According to the dry method, an inorganic plate having a three-dimensional uneven pattern on its surface is easily manufactured, and such an inorganic plate is highly evaluated as an outer wall material. However, it is not desirable to consume a large amount of the above-mentioned wood reinforcing material from the viewpoint of the present situation that there is a shortage of wood resources and the protection of the global environment. Therefore, recently, old wood, waste wood, etc. are also used as materials for the wood reinforcing material, but bamboo fiber is also attracting interest as a substitute for the wood reinforcing material. Bamboo grows in the temperate zone or in the tropics, has a large accumulation amount, is an almost unused resource, and grows very quickly, so there is no resource problem. However, bamboo fibers are highly elastic, providing a lightweight inorganic board product with low density and high strength. As described above, bamboo is not a resource problem, but since bamboo fiber contains a large amount of saccharides that are cement hardening inhibitors, it is necessary to remove the saccharides when using it as a reinforcing material for cement-based inorganic boards. There is. In addition, bamboo fiber is excellent in reinforcing effect because it has high elasticity as described above, but on the other hand, if the cement in the mat is not sufficiently hardened during heating and pressing, the springback phenomenon of the molded product will occur at the time of demolding and the prescribed shape No product can be obtained, and the density of the product becomes too low to obtain sufficient strength. Therefore, in order to use bamboo fibers as a reinforcing material for cement-based inorganic boards, the sugars contained in the bamboo fibers are removed as described above, which allows the cement in the mat to be hardened and debonded smoothly during heating and pressing. It has been an essential condition in the past to prevent springback of a molded product during molding.

[0003]

2. Description of the Related Art Conventionally, as a means for removing sugars in bamboo fiber or preventing springback of a molded inorganic plate using bamboo fiber as a reinforcing material after demolding, water absorption of bamboo fiber Method of repeatedly performing dehydration treatment (JP-A-2-26854, JP-A-2-48446), method using bamboo fiber having an average fiber length of 20 cm or more and an average diameter of 3 mm or less (JP-A-2-46046) Etc. are provided.

[0004]

In the above-mentioned conventional method, the method of repeatedly performing water absorption-dehydration treatment on bamboo fiber requires a great deal of labor and energy, and waste water treatment is also required, which increases the cost of bamboo fiber. In addition, if the length and diameter of the bamboo fiber are limited to those within a predetermined range, the yield of the bamboo fiber will be low, and the labor for selection will be increased.This method also increases the cost of the bamboo fiber, and the fiber length 20
There is a problem that long fibers of cm or more are difficult to mix uniformly with the cement-based inorganic powder.

[0005]

According to the present invention, as a means for solving the above-mentioned conventional problems, a cement-based inorganic powder 40 is used.
~ 70 parts by weight, the weight ratio of bamboo reinforcement and wood reinforcement is 1
Reinforcing material 1 mixed in a ratio of 00:00 to 20:80
5 to 35 parts by weight, a step 1 of adjusting the water content of the molding material in which 2 to 15 parts by weight of the alkali metal silicate is mixed with 2 to 15 parts by weight with respect to 100 parts by weight of the cement-based inorganic powder to 40 to 60% by weight, the molding Step 2 of forming the mat by spraying the material on the template, step 3 of compressing the mat and spraying water vapor for primary curing, step 3 of curing the primary cured mat in a water-containing state for final curing 4. The present invention provides a method for producing an inorganic plate, which comprises the above steps 1, 2, 3, and 4. The above wood reinforcing material is 10% by weight in the reinforcing material.
It is preferable that the content is in the range of 80% by weight or more, and wood pieces are preferable among the wood reinforcing materials.

[Cement-based inorganic powder] The cement-based inorganic powder used in the present invention is a hydraulic inorganic powder containing calcium silicate as a main component. For example, Portland cement, or blast furnace cement with Portland cement mixed with blast furnace slag,
There are fly ash cement mixed with fly ash, silica cement mixed with a silica substance such as volcanic ash, silica fume, and clay, alumina cement, blast furnace slag, and the like.

[Bamboo Reinforcement Material] The bamboo reinforcement material used in the present invention is a fibrous material, a chip material,
There are flakes. In order to produce such a bamboo reinforcing material, raw bamboo is usually cut into strips of about 1 to 1.2 m without removing the epidermis, and is crushed by a roll or the like to split the split. The product is cut into pieces of about 25 to 30 cm to obtain split pieces, and if desired, the split pieces are immersed in water to soften them and then crushed into chips. The chips may be used as they are as a bamboo reinforcing material, but if desired, the chips are further fragmented by flakers. Alternatively, the split pieces may be defibrated with a fluffing machine, and if desired, further fine-fiberized by a turbo mill. A preferable bamboo reinforcing material is a flake-shaped material having a length of 15 to 40 mm, a width of 2 to 5 mm, and an aspect ratio (length / thickness) of 10 to 80.

[Wood Reinforcement Material] The wood reinforcement material used in the present invention includes wood powder, wood wool, wood chips, wood fibers, wood pulp, wood fiber bundles, etc., and the wood reinforcement material is hemp fiber or bacas. A material containing lignocellulose as a main component, such as rice husk, rice straw, etc., may be mixed. A preferred wood reinforcing material is a width of 0.5 to 2.0 mm, a length of 1 to 20 mm, an aspect ratio (length / thickness) of 20 to 30 wood pieces, and a diameter of 0.1 to 0.1 mm.
There are branched and / or curved and / or bent wood fiber bundles with a length of 2.0 mm and a length of 2-35 mm.

[Aggregate] In the present invention, an aggregate, particularly a lightweight aggregate, may be added in addition to the cement-based inorganic powder and the wood reinforcing material. As the lightweight aggregate, inorganic foams such as pearlite, shirasu balloon, expanded shale, expanded clay, calcined diatomaceous earth, fly ash, coal waste, and crushed foam concrete are used. The above lightweight aggregate is usually added in an amount of 30 parts by weight or less based on the total solid content of the mixture.

[Third component] In the above composition, if desired, a curing accelerator such as aluminum sulfate, magnesium sulfate, calcium sulfate, and aluminates, wax, wax,
A paraffin, a surfactant, a waterproofing agent such as silicon, a water repellent, or the like may be added.

[Alkali metal silicate] The alkali metal silicate used in the present invention is lithium silicate, potassium silicate, sodium silicate, etc., and two or more kinds of the above alkali metal silicates are mixed and used. The preferred alkali metal silicate salts may be potassium silicate and sodium silicate, which are inexpensive and easily available. The molar ratio _{Si O 2 / Na 2 O =} 2~4 desired silicate and an alkali metal in said alkali metal silicate, Si O ₂ / K
₂ O = 3-4.

[Production of Inorganic Plate] In order to produce the inorganic plate of the present invention, a molding material is usually prepared by mixing a predetermined amount of the above composition. In this case, the cement-based inorganic powder 40 to 70
Parts by weight, 15 to 35 parts by weight of a reinforcing material composed of a mixture of the bamboo-based reinforcing material and the wood-based reinforcing material, and the alkali metal silicate is 2 to 100 parts by weight of the cement-based inorganic powder.
˜15 wt% is added and mixed, and water is added to the molding material to adjust the water content to 40 to 60 wt% (step 1). In the above reinforcing material, the weight ratio of the bamboo reinforcing material and the wood reinforcing material is from 100: 0 to 20:80, preferably 9
It is mixed in a ratio of 0:10 to 20:80. When the wood reinforcing material is added in an amount exceeding 80% by weight in the reinforcing material, it is difficult to obtain a low density product, and the utilization efficiency of the bamboo reinforcing material is also low. In the present invention, only the bamboo reinforcing material may be used as the reinforcing material, but the surface of the bamboo reinforcing material is fine, and the dispersibility is poor in the subsequent forming step, and uniform dispersion is difficult to perform. 〝Therefore, it is difficult to obtain uniform quality. Therefore, in order to obtain a product of uniform quality, 10% by weight of the above-mentioned wood reinforcing material, especially wood pieces, is contained in the reinforcing material.
It was found that the above mixing improves the above-mentioned dispersibility and spraying workability. As a preferable method for preparing the molding material, the reinforcing material and the alkali metal silicate diluted with water are mixed to allow the alkali metal silicate to penetrate into the bamboo reinforcing material and / or the wood reinforcing material, and then In this method, the cement-based inorganic powder, the aggregate and the like are added and mixed. The molding material thus prepared is sprayed on a template to form a mat (step 2). Then, the periphery of the mat is sealed with a sealing frame material and compressed, and steam is injected to heat the mat to accelerate the curing reaction of the mat and the mat size of the mat is determined by the sealing frame material.
The specific gravity is regulated, and the water vapor is retained inside the sealing frame material to primarily cure the mat (step 3). The pressure of the steam applied in the above heating and pressing is 0.12 to 0.
30MPa, the injection time is usually 2 to 10 seconds,
The clamping pressure is usually 2 to 5 MPa, and the clamping time is usually 2 minutes or more, but from the viewpoint of productivity, it is preferably 2 to 15 minutes. When the steam injection time is less than 2 seconds, the primary curing of the mat tends to be insufficient and the demolding workability tends to be poor, and the strength and freeze-thaw resistance of the product obtained may not be satisfied, while it exceeds 10 seconds. Since the primary cured product of the mat may explode, in this case, open the pressure reducing valve etc. and maintain the internal pressure of the mat inside the seal frame material while maintaining the pressure-tightened state before demolding the primary cured product. It is necessary to gradually lower it to prevent the primary cured product from bursting. The primary cured product of the mat obtained after the pressing is cured in a water-containing state (step 4). To cure the primary cured product in a water-containing state, it is preferable to coat the primary cured product with a water-impermeable film in order to prevent evaporation of water. When the water content of the primary cured product is small, water immersion is performed or water is sprayed. When water is sprayed, it is preferable to cover the primary cured product with a water impermeable film in order to prevent evaporation of water. The curing time is usually 7 to 15 days, and the primary curing is finally cured by the curing. After the above curing, a product is subjected to a surface treatment if desired through a drying process. In the pressing step other than the above examples, water vapor may be injected from the back surface of the mat, or may be injected from both front and back surfaces.
The inorganic plate of the present invention may have a two-layer structure or a three-layer structure. In the case of a two-layer structure, first, the molding material in which the reinforcing material with a small particle size is mixed is scattered on the template, and then the molding material with the reinforcing material in a large particle size is mixed on the template. To form a two-layered mat, and heat and press the mat to form a surface layer portion having a dense structure with a molding material in which a reinforcing material having a small particle diameter is mixed to form a matte having a large particle diameter. The backing layer having a rough structure is formed by the molding material in which the reinforcing material is mixed. Further, in the case of a three-layer structure, a molding material in which a reinforcing material having a fine particle size is mixed is further spread thereon to form a three-layer structure mat, and the mat is heated and pressed to obtain the above-mentioned particle size A layer made of a molding material in which a large reinforcing material is mixed is a core layer portion, and a layer made of a molding material in which a reinforcing material having a small particle size is mixed is a back layer portion. When a three-layered structure is formed, two mats having the two-layered structure may be stacked and heated and pressed. In this case, the mat is laminated so that the layers made of the molding material mixed with the reinforcing material having a large particle diameter are in contact with each other.

[0013]

[Function] A molding material composed of a mixture of cement-based inorganic powder, a reinforcing material, an alkali metal silicate and, if desired, an aggregate, particularly an inorganic foam is formed on a template as a mat, and the mat is formed. When the mat is pressed and steam is sprayed, the mat is rapidly heated to the inside, and the alkali metal silicate reacts rapidly with the cement-based inorganic powder.
That is, the alkali metal component (Li ₂
(O, K ₂ O, Na ₂ O, etc.) accelerates the hydration hardening of the cement-based inorganic powder, and the silicic acid content (Si O ₂ ) gels, while the lime content (Ca) of the cement-based inorganic powder is gelled. Even when the cement reinforcing agent such as a saccharide is contained in not only the bamboo-based reinforcing material but also the wood-based reinforcing material, it reacts with O) and the curing of the cement-based inorganic powder proceeds smoothly throughout the mat. The mat primary cured in this manner has a sufficient primary strength for demolding work, and thus can be demolded by pressing for a short time (preferably 2 to 15 minutes). When the bamboo reinforcing material and / or the wood reinforcing material is first impregnated with the alkali metal silicate aqueous solution,
The above reaction is performed with the cement-based inorganic powder around which the aqueous solution of alkali metal silicate leached from the inside and the surface of the bamboo reinforcing material and / or the wood reinforcing material by pressing is present. In this case, in the case where not only the bamboo reinforcing material but also the wood reinforcing material contains a cement hardening inhibiting substance, when the aqueous solution of alkali metal silicate is penetrated into the bamboo reinforcing material or the wood reinforcing material, Since the surface of the reinforcing material or the wood reinforcing material is coated with the alkali metal silicate, it prevents the elution of the cement hardening inhibiting substance contained in the bamboo reinforcing material or the wood reinforcing material. Hardening of the powder proceeds more smoothly. The inorganic board product obtained by the present invention has high strength and uniform physical properties even at low density due to the high elasticity of the bamboo reinforcement, but the content of the bamboo reinforcement in the reinforcement is 20. If it is less than 10% by weight, the density becomes high, the weight of the product becomes large, and the utilization efficiency of the bamboo reinforcing material decreases.

[0014]

【Example】

[Embodiment 1] FIGS. 1 to 5 show an embodiment of a process for producing an inorganic plate of the present invention. In FIG. 1, a mold plate (1) is conveyed by a conveyor (2) in the direction of an arrow, and a mold release agent is sprayed from a spray nozzle (3) on a mold surface of the mold plate (1). 1) is introduced into the forming device (4) by the conveyor (2). The forming device (4) includes a forming chamber (5) and a blower chamber (7) in which a blower (6) provided at an outlet of the forming chamber (5) is provided.
The forming chamber (5) is opposed to the blowing chamber (7).
A reverse blower (8) provided at the entrance of the hopper, and a hopper (9) provided at the ceiling of the forming chamber (5);
Molding material supply conveyor (10) connected to the hopper (9)
And a molding material supply sieve (11) installed on the conveyor (10)
Consists of

The molding material R is sprinkled from the sieve (11) onto the conveyor (10) to form a hopper in the forming chamber (5).
From (9) into the forming chamber (5),
It is scattered and deposited on the template (1) introduced by the conveyor (2) into the forming chamber (5). At this time, air is blown from the blower (6) of the air blower chamber (7) to the inlet side to wind-select the molding material R, and the molding material R in which the reinforcing material having a fine particle diameter is mixed is arranged on the lower side, The molding material R in which the large reinforcing material is mixed should be on the upper side. At this time, the reverse air is blown to the outlet side by the reverse air blower (8). So that In this way, a mat (12) having a dense structure on the lower side and a coarse structure on the upper side is formed, and the mat (12) is trimmed to a predetermined size, if necessary, and then the pressing device shown in FIG. Introduced in 13).

The clamping device (13) includes a surface plate (15) installed on a base (14) and a lower pressure plate (a heat plate mounted on the surface plate (15)). 16), a movable platen (18) attached to the lower end of the hydraulic cylinder (17), an upper pressure plate (19) which is a heating plate attached to the lower side of the movable platen (18), and A steam injection board (20) attached to the lower side of the pressure board (19),
A seal frame member (22), which is a sealing means arranged below the steam jet board (20) and suspended by a link (21).
And a frame (23) that supports the hydraulic cylinder (17) and guides the movable plate (18). Water vapor jet board (20)
As shown in FIG. 3, is a main body (24), a steam pipe (25) inserted into the main body (24), and a number of nozzles which are inserted from the steam pipe (25) and open on the lower surface of the main body (24). It consists of a pipe (26).

The mat 12 formed by the forming device 4 is introduced into the pressing device 13 and set on the lower press platen 16 as shown in FIG.
As shown in (3), the lower pressure plate (16) and the upper pressure plate (19) are clamped and the periphery thereof is sealed by the seal frame member (22).
As described above, the pressing pressure in this case is usually 2 to 5 MPa. Then, when the predetermined pressure is reached, steam is injected from the steam injection plate (20) to the mat (12) through the steam pipe (25) and the nozzle pipe (26). As described above, the pressure of the steam is 0.12 to 0.30 MPa, and the injection time is usually 2 to 10 seconds. In this case, a releasable net or mat, such as a glass fiber net coated with Teflon resin, may be interposed between the mat (12) and the steam jet plate (20) so that steam can pass through. Further, instead of the sealing frame member (22), a sealing means such as a rubber belt or a heat-resistant adhesive tape may be used for sealing.

By the steam injection to the mat (12), the curing proceeds smoothly by the reaction between the cement-based inorganic powder and the alkali metal silicate as described above, and the primary strength is shortened (usually within 5 minutes). Improves and makes demolding work easier. As described above, the primary strength of the mat (12) is improved in a short time during the press forming, and the demolding operation is facilitated, so that the upper pressing plate (19) of the pressing device (13) is raised. The mold is opened, and the primary curing mat (27) shown in FIG. 5 is removed from the mold plate (1).

[Examples 2 to 10 and Comparative Examples 1 and 2] Examples 2 to 10 and Comparative Examples 1 and 2 shown in Table 1 using the forming device (4) and the clamping device (13) of Example 1. Inorganic plate samples 1 to 11 were manufactured under the pressure curing and curing conditions shown in Table 1 by using the molding material having the composition of. The physical properties of the inorganic plate samples 1 to 11 produced in Examples 2 to 10 and Comparative Examples 1 and 2 are shown in Table 1.

[0020]

[Table 1]

[Discussion] The sample 10 of Comparative Example 1 uses a molding material to which an alkali metal silicate is not added, and a pressing for 10 minutes results in insufficient primary curing and makes mold release impossible. Further, the sample 11 of Comparative Example 2 in which the content of bamboo fiber is less than 80% by weight in the reinforcing material is excellent in product strength and freeze / thaw resistance, but has a large specific gravity of 1.25 and a large product weight. On the other hand, Samples 2 to 9 of Examples 3 to 10 of the present invention have sufficiently large product strength and freeze-thaw resistance and excellent physical properties, and have a specific gravity of 1.22 or less and are lightweight. On the other hand, in Sample 1 in which only the bamboo fiber of Example 2 is used as the reinforcing material, the quality is slightly uneven and the strength is slightly reduced.

[0022]

Therefore, according to the present invention, even if bamboo fiber containing a cement hardening inhibiting substance is used as a reinforcing material, the mat can be sufficiently hardened by pressing in a short time, so that a springback phenomenon does not occur. In addition, the investment in the template can be greatly reduced, and even if the inorganic plates are pressed one by one, the productivity does not decrease, and if the inorganic plates are pressed one by one, the inorganic plates can be stacked as before. It is possible to obtain a product with less variation in thickness than when tightening by pressing. Thus, according to the present invention, it is possible to manufacture an inorganic plate having an extremely efficient and uniform thickness by using bamboo fiber which is not a resource problem as a reinforcing material.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 to 5 show an embodiment of the present invention.

[Figure 1] Matte forming process diagram

FIG. 2 is a schematic view of a pressing device.

FIG. 3 is a schematic cross-sectional view of a steam jet board.

FIG. 4 is a schematic diagram of a clamping device in a clamping state.

FIG. 5 is a side sectional view of a molded product.

[Explanation of symbols]

 12 Mat 13 Pressing device 27 Primary curing mat

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location C04B 18:26 18:24 14:18) 111: 00

Claims (5)

[Claims] 1. A cement-based inorganic powder of 40 to 70 parts by weight, a bamboo reinforcing material and a wood reinforcing material in a weight ratio of 100: 0 to 20:
15 to 35 parts by weight of reinforcing material mixed in a ratio of 80,
Step 1 of adjusting the water content of the molding material in which the alkali metal silicate is mixed in an amount of 2 to 15 parts by weight with respect to 100 parts by weight of the cement-based inorganic powder to 40 to 60% by weight; Step 2 of spraying and forming a mat, Step 3 of compressing the mat and spraying water vapor for primary curing, Step 4 of curing the primary cured mat in a water-containing state for final curing, Step 1 above Method for producing inorganic plate consisting of 2, 3, 4 2. The method for producing an inorganic plate according to claim 1, wherein the reinforcing material contains wood reinforcing material in a range of 10% by weight to 80% by weight. 3. The wooden reinforcing material is a piece of wood.
The method for producing an inorganic plate described in 4. The alkali metal silicate is one or more alkali metal silicates selected from lithium silicate, potassium silicate, and sodium silicate. Method for manufacturing inorganic plate 5. The water vapor pressure in step 3 is 0.12 to 0.
30 MPa, the injection time is 2 to 10 seconds, the pressing time is 2 minutes or more, and the curing time in step 4 is 7 to
The method for producing an inorganic plate according to claim 1, 2 or 3 or 4, which is for 15 days.