JPH08225379A - Production of inorganic board - Google Patents

Abstract

PURPOSE: To efficiently obtain an inorganic board having a uniform thickness by mixing a cement with a woody reinforcing material and an alkali metallic silicate at a prescribed ratio, regulating the moisture content, scattering the resultant mixture on a die plate, pressing the formed mat and jetting steam thereon. CONSTITUTION: A cement-based inorganic powder (e.g. Portland cement) in an amount of 40-70 pts.wt. is mixed with 20-35 pts.wt. woody reinforcing material (e.g. woody pulp) and an alkali metallic silicate (e.g. sodium silicate) in an amount of 2-15 pts.wt. based on 100 pts.wt. cement-based inorganic powder and the moisture content of the resultant forming material is regulated to 40-60wt.%. The regulated forming material is then scattered over a die plate to form a mat. The formed mat is pressed and steam is jetted thereon to primarily harden the mat. The primarily hardened mat is then cured in a hydrous state and finally hardened to afford an inorganic board. The pressure of the steam jetted in pressing the mat is preferably 0.12-0.3MPa and the jetting time is preferably 2-10sec. The pressing time is preferably >=2min.

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]

2. Description of the Related Art Conventionally, an inorganic plate in which a wood reinforcing material such as a piece of wood, wool, or wood pulp is mixed with cement has been provided as a building plate such as an outer wall material or 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.

[0003]

However, in the above-mentioned conventional dry production method, although the hardening of the cement-based inorganic powder is promoted by heating and pressing, it takes 10 to 10 days to reach the demolding after pressing. It requires a long period of time, the efficiency of use of templates is low, and productivity is very low.To cope with mass production, a large number of templates are required and investment in templates is large. (For example, JP-A-54-48821). The reason why it takes a long time to release the mold after pressing is that the cement-based inorganic powder requires a long time for hydration hardening, and if the mold is released in a short time, the molding material causes springback. It can be mentioned that a molded product having a desired shape cannot be obtained. Particularly in some tree species such as larch and yellow lauan, when a cement hardening inhibitor such as a saccharide contained in wood acts on the cement-based inorganic powder, it inhibits the hardening of the cement-based inorganic powder. Further, the curing time is delayed, often resulting in poor curing, and molding becomes impossible. However, from the viewpoint of effective use of wood resources, it is desirable to use wood scrap generated from the demolition of buildings as a wood reinforcing material. However, the wood scrap is diverse and often includes the tree species containing a large amount of the sugars. Therefore, it is difficult and very troublesome to sort out and remove only such a tree species.
Furthermore, even if the same tree species are used, the sugar content differs between the core material and the sapwood, and there is a problem in that the time required for demolding after press molding varies greatly. Therefore, it has been desired to put into practical use a method for producing an inorganic plate that shortens the time from press molding to demolding and makes it substantially constant, regardless of the type of wood reinforcing material, core material, or sapwood.

[0004]

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, wood reinforcing material 20 to 35 parts by weight, alkali metal silicate salt in an amount of 2 to 15 parts by weight based on 100 parts by weight of the cement-based inorganic powder, and a water content of 40 to 40 parts by weight.
Step 1 of adjusting the weight to 60% by weight, Step 2 of forming a mat by spraying the molding material on a template, Step 3 of pressing and matting the mat to perform primary curing by spraying steam, and Primary cured mat. And a final curing step of curing in a water-containing state, and a method for producing an inorganic plate comprising the above steps 1, 2, 3, and 4.

[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 in which blast furnace slag is mixed with Portland cement,
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.

[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. The wood reinforcement material is bamboo fiber, hemp. A material containing lignocellulose as a main component such as fiber, bacas, chaff, rice straw, etc. may be mixed. The 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, a diameter of 0.1 to 2.0 mm, and a length of 2 to 35 mm. There are branched and / or curved and / or bent wood fiber bundles of.

[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] If desired, the above composition may further contain a hardening accelerator such as aluminum sulfate, magnesium sulfate, calcium sulfate, aluminates, water glass, or a wax,
A waterproofing agent such as wax, paraffin, a surfactant, and silicone, a water repellent, and the like may be added.

[Alkali metal silicate salt] The alkali metal silicate salt used in the present invention is lithium silicate, potassium silicate, sodium silicate, etc., and two or more kinds of the above alkali metal silicate salts 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, 20 to 35 parts by weight of the wood reinforcing material, and the alkali metal silicate are added and mixed at a ratio of 2 to 15% by weight based on 100 parts by weight of the cement-based inorganic powder. Is added to adjust the water content to 40 to 60% by weight (step 1). As a preferable preparation method, the above-mentioned wood reinforcing material and the above-mentioned alkali metal silicate salt diluted with water are mixed to allow the alkali metal silicate salt to penetrate into the wood reinforcing material, and then the above-mentioned cement-based inorganic powder and aggregate, etc. Is 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 size and specific gravity of the mat are regulated by the sealing frame material. The water vapor is retained inside the seal frame material to primarily cure the mat (step 3). The pressure of the steam applied in the heating and pressing is 0.12 to 0.30 MPa, and the injection time is usually 2 to 3.
It is 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, a molding material in which a wood reinforcing material having a fine particle diameter is mixed is sprayed on a template, and then a molding material in which a wood reinforcing material having a large particle diameter is mixed thereon is molded. A mat having a two-layer structure is formed by spraying on a board, and the mat is heated and pressed to form a surface layer portion having a dense structure using a molding material in which a wood reinforcing material having a fine particle diameter is mixed. A back layer having a rough structure is formed by a molding material mixed with a wood reinforcement having a large diameter. Furthermore, in the case of a three-layer structure, a molding material in which a wood reinforcing material having a fine particle diameter is mixed is further sprayed thereon to form a three-layer structure mat, and the mat is heated and pressed to obtain the above-described particle diameter. The layer made of the molding material in which the wood reinforcing material having a large particle size is mixed is used as the core layer portion, and the layer made of the molding material in which the wood reinforcing material having a small particle diameter is mixed is used as the 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 layers of a molding material mixed with a woody fiber having a large particle diameter are in contact with each other.

[0011]

[Function] A molding material composed of a cement-based inorganic powder, a wood reinforcing material, an alkali metal silicate and, if desired, an aggregate, especially an inorganic foam, is formed into a mat on a template, When the mat is pressed and water vapor is injected, 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 components (Li ₂ O, K ₂ O, Na ₂ O, etc.) of the alkali metal silicate accelerate the hydration hardening of the cement-based inorganic powder, and the silicic acid component (SiO ₂ ) The cement-based inorganic powder reacts with the lime (CaO) of the cement-based inorganic powder and hardens the cement-based inorganic powder as a whole even if the wood-based reinforcing material contains a cement-hardening inhibitor such as a saccharide. Proceed smoothly. 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 aqueous alkali metal silicate solution is first infiltrated into the wood reinforcing material, the above-mentioned reaction is performed with the cement-based inorganic powder around which the aqueous alkali metal silicate solution is present from the wood reinforcing material by pressing. . In this case, when the wood reinforcement contains a cement hardening inhibitor, the surface of the wood reinforcement is coated with the alkali metal silicate when the aqueous solution of the alkali metal silicate is penetrated into the wood reinforcement. In this state, the elution of the cement hardening inhibitor contained in the wood reinforcing material is prevented, so that the hardening of the cement inorganic powder proceeds more smoothly.

[0012]

【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 sprayed from the sieve (11) onto a conveyor (10) and is supplied to a hopper of a 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 blower chamber (7) to the inlet side to wind-select the molding material R, and the molding material R in which the wood reinforcing material having a fine particle diameter is mixed The molding material R mixed with the large wood reinforcing material is placed 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 pressing 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 above-mentioned forming device (4) is introduced into the pressing device (13) and set on a lower pressing plate (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.

[0016] By the steam injection to the mat (12), as described above, the reaction between the cement-based inorganic powder and the alkali metal silicate hardens smoothly, and the primary strength is reduced in a short time (usually within 5 minutes). And the demolding work becomes 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).

[Embodiments 2 to 16] Using the forming apparatus (4) and the pressing apparatus (13) of Embodiment 1, Tables 1 and 2 were used.
Inorganic plate samples 1 to 15 were manufactured under the compacting conditions shown in Tables 1 and 2 by using the molding material having the composition of Example 2 above
The physical properties of the inorganic plate samples 1 to 15 manufactured in Table 1 are shown in Table 1.
And shown in Table 2.

[0018]

[Table 1]

[Table 2]

[Comparative Examples 1 to 6] Using the forming material (4) and the pressing device (13) of Example 1, a molding material having the composition shown in Table 3 was used, and the inorganic material was obtained under the pressing curing conditions shown in Table 3. Plate samples 16 to 21 were produced. Table 3 shows the physical properties of the inorganic plate samples 16 to 21 produced in Comparative Examples 1 to 6 above.

[0020]

[Table 3]

[Discussion] Sample 16 of Comparative Example 1 uses a molding material to which no alkali metal silicate is added, and primary compaction is insufficient due to insufficient compression for 10 minutes, and the mold cannot be removed. Sample 17 of Comparative Example 2 in which the steam injection time was less than 2 seconds had insufficient product strength and freeze-thaw resistance, and Sample 18 of Comparative Example 3 in which the steam injection time exceeded 10 seconds Destruction occurs. Curing time is less than 7 days 5
The sample 19 of Comparative Example 4, which was a day, had insufficient strength and freeze-thaw resistance, and the sample 20 of Comparative Example 5, which had a compression time of 1 minute which was less than 2 minutes, had poor strength and freeze-thaw resistance. Enough
Sample 21 of Comparative Example 6 in which the alkali metal silicate was added in an amount exceeding 15 parts by weight and 16.7 parts by weight with respect to the cement-based inorganic powder had poor freeze-thaw resistance and cracked the product in layers. did. On the other hand, Sample 1 of Examples 2 to 16 of the present invention
No. to No. 15 are sufficiently large in both product strength and freeze-thaw resistance and show excellent physical properties.

[0022]

Therefore, in the present invention, the pressing time can be greatly shortened, so that the investment in the template can be greatly saved, and the productivity is lowered even if the inorganic plates are pressed one by one. Instead, by pressing the inorganic plates one by one, it is possible to obtain the one with less variation in thickness than the conventional case where the inorganic plates are stacked and pressed. In the present invention, since the pressing time is shortened irrespective of the type of the wood reinforcing material, it is also possible to reuse the construction waste material as the wood reinforcing material. Thus, the present invention provides an extremely efficient inorganic material having a uniform thickness. Plates can be manufactured.

[Brief description of drawings]

 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

[Procedure amendment]

[Submission date] October 18, 1995

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

[Correction content]

Furthermore aluminum sulfate if desired in the [third component] above composition, magnesium sulfate, calcium sulfate, curing accelerator and waxes such as aluminate compounds, waxes,
A paraffin, a surfactant, a waterproofing agent such as silicon, a water repellent, or the like may be added.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0018

[Correction method] Change

[Correction content]

[0018]

[Table 1]

(72) Inventor Shuichi Kawai 70-35 Fukakusa Taniguchi-cho, Fushimi-ku, Kyoto-shi, Kyoto Prefecture (72) Inventor Dwight Agoborn Eyusebio 1-04 Takaba-cho, Fushimi-ku, Kyoto-shi, Kyoto

Claims (4)

[Claims] 1 to 40 parts by weight of a cement-based inorganic powder, 20 to 35 parts by weight of a wood reinforcing material, and 2 to 15 parts by weight of an alkali metal silicate are mixed with 100 parts by weight of the cement-based inorganic powder. Step 1 of adjusting the moisture content of the molding material to 40 to 60% by weight, Forming a mat by spraying the molding material on a mold plate 2, Pressing the mat and spraying water vapor to cure it primarily. Step 3, a step of curing the primary-cured mat in a water-containing state and finally curing the mat; a method of manufacturing an inorganic plate comprising the above steps 1, 2, 3, and 4 2. The method according to claim 1, wherein an inorganic foam is further added to the molding material in an amount of 30 parts by weight or less. 3. The production of an inorganic plate according to claim 1, wherein the alkali metal silicate is one or more alkali metal silicates selected from lithium silicate, potassium silicate and sodium silicate. Method 4. The process according to claim 3, wherein the water vapor pressure in step 3 is 0.12 to 0.1.
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, which is for 15 days.