JP3530699B2 - Method for producing inorganic plate-like body - Google Patents

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 an inorganic plate-like body having excellent fire resistance, which is light in weight while maintaining practical strength as a building material such as a ground plate and an outer wall base material. .

[0002]

2. Description of the Related Art As a building material such as a ground board or an outer wall base material, a material having high strength and excellent fire resistance is used. Examples include cement-based building materials such as cement-calcium board, slag cement board, and wood chip cement board.
However, these cement-based building materials have problems that they are heavy and impair the workability, and that they are hard and poor in workability.

[0003] As a material that is light and has excellent workability, there are mineral fiber boards formed by using rock wool or the like with a binder, but these have only the strength to the extent that they can be used as a decorative material for interiors. Therefore, it is not sufficient as a building material such as a base plate and outer wall base material. In addition, as a material having both lightness and strength, the applicant of the present invention has previously filed Japanese Patent Application Laid-Open No.
According to the inorganic building board described in Japanese Patent Publication No. -50417, a wet inorganic board obtained by wet-making a slurry containing mineral fibers, an inorganic powder and a binder as essential components is used as upper and lower layers,
In the meantime, a three-layer inorganic building board has been proposed, which is obtained by laminating an intermediate layer mixture containing an inorganic foam, a fibrous substance and a binder as essential components, press-integrating, heating and drying. According to this, by combining the low-density and light-weight middle layer with the high-density and high-strength upper and lower layers, it is possible to satisfy the contradictory physical properties of light weight and high strength, and also to meet the criteria of non-combustible and semi-incombustible materials to prevent fire. An excellent product was obtained.

However, the building board obtained here is used as an interior base material such as a so-called gypsum board having a specific gravity of 0.43 and a bending strength of 75 kgf / cm ² , and as it is, it is used as a base board or outer wall base material. It is insufficient as a building material.
In order to obtain the desired high-strength plate, it is necessary to make the upper and lower layers more dense and high-strength, and for that purpose, the adhesive is sufficiently bonded to prevent springback due to the repulsive force of the mineral fibers. It is necessary to hot press the upper and lower layers at high density until it is hardened so as to express force, but since the upper and lower layers obtained by wet papermaking contain a large amount of water,
In order to dry the upper and lower layers and harden the binder, hot pressing for a very long time is required, which causes a problem that production with high production efficiency cannot be performed.

In view of the above-mentioned problems, the present invention aims to obtain an inorganic plate-like body excellent in fireproofness while attaining weight reduction while maintaining practical strength as a building material such as a ground plate and outer wall base material. It is an object of the present invention to provide a method for efficiently producing an inorganic plate-like body by a hot press for a short time.

[0006]

In order to achieve the above-mentioned object, the inventors of the present invention have conducted earnest research and as a result, at least upper and lower layers contain an isocyanate group that rapidly reacts and cures in hot water to develop an adhesive force. By adding an adhesive, more preferably by adding a substance that reacts with those adhesives, a desired inorganic plate-like body can be obtained in a short hot-pressing step and a subsequent drying step by a dryer. Based on this finding, the present invention was completed.

In order to achieve the above-mentioned object, the inorganic plate-like material according to the present invention is characterized in that, in claim 1, a mineral fiber and an inorganic powdery material are mainly contained, and an adhesive containing at least an isocyanate group is added to water. A step of paper-making a wet inorganic plate to be a lower layer from a slurry consisting of, a step of laminating an intermediate layer mainly composed of an inorganic foam, and adding a fibrous material and an adhesive on the lower layer, and a mineral substance An adhesive mainly composed of fibers and inorganic powders and containing at least an isocyanate group
A step of forming a wet inorganic plate to be an upper layer part from a slurry formed by adding it to water and stacking it on the middle layer part to obtain a laminate,
A step of heating and pressing the laminate with a hot press to react the isocyanate group-containing adhesive with water to form urea to generate primary strength, and heat-drying the press-integrated laminate to obtain an isocyanate group-containing adhesive. Final curing of the adhesive and other adhesives contained therein to generate secondary strength. Method for producing inorganic plate-like body

More preferably, in the second aspect,
The method for producing an inorganic plate-shaped body according to claim 1, wherein a substance that reacts with an isocyanate group of an adhesive containing an isocyanate group is used as an upper layer portion and a lower layer portion,
Alternatively, it is characterized in that it is added to a wet inorganic plate obtained by papermaking from a slurry. Hereinafter, the method for producing the inorganic plate-shaped body of the present invention will be specifically described.

As the mineral fibers forming the upper and lower layers,
Examples thereof include rock wool, slag wool, mineral wool, nickel wool, and glass fiber, which can be used alone or in combination of two or more kinds. The content of the mineral fibers is preferably 20 to 60% by weight of the entire upper and lower layers. This is because if it is less than 20% by weight, the desired bending strength cannot be obtained.
This is because if the amount exceeds 0% by weight, the ratio of the inorganic powdery material decreases relatively, and the desired surface hardness cannot be secured.

The inorganic powdery material is for increasing hardness and screwing performance while maintaining fire resistance, and examples thereof include calcium carbonate, silica sand, microsilica, slag, and aluminum hydroxide. These can be used alone or in combination of two or more. The content of the inorganic powder is 40 to 7 in the entire upper and lower layers.
It is preferably 0% by weight. This is because if it is less than 40% by weight, the desired surface hardness cannot be obtained, and if it exceeds 70% by weight, the proportion of the mineral fiber that imparts strength is small and the desired bending strength cannot be obtained.

The role of the adhesive in the upper and lower layers is to combine and integrate the mineral fibers and the inorganic powder to achieve the final practical strength, and to use hot water in a short time hot pressing process. Above all, the upper and lower layers are required to be sufficiently densified and adhered and fixed so that the strength enough to be handled can be exhibited. As the adhesive, an adhesive containing an isocyanate group capable of expressing the primary strength in a short time and finally being sufficiently heat-cured to add secondary strength so that the laminate can be handled such as being transported, Use an adhesive such as phenol or epoxy together.

When the isocyanate group-containing adhesive is added to the upper and lower layers, it rapidly reacts with hot water in the hot pressing process to form urea, thereby firmly bonding the wet-processed upper and lower layers. Thus, it is possible to produce high-density upper and lower layers with high productivity by a short-time hot-pressing reaction.
As the isocyanate group-containing adhesive, Monomeric M
DI (4,4'-diphenylmethane diisocyanate), polymeric MDI, TDI (tolylene diisocyanate), XDI (xylylene diisocyanate),
HDI (hexamethylene diisocyanate), H ₁₂ M
DI (4,4'-methylenebis (cyclohexyl isocyanate)), IPDI (isophorone diisocyanate) and their various polyols (low molecular weight polyols, polyether polyols, polyester polyols, polycarbonate diols, acrylic polyols, silicone polyols) , 2-hydroxyethyl acrylate, etc.), dibasic acids (azelaic acid, adipic acid, sebacic acid, isophthalic acid, terephthalic acid, etc.),
Reaction products with various epoxy resins, castor oil, liquid polybutadiene, active hydrogen compounds such as neoprene, or
Various modified products including those with improved dispersibility in water by adding various modifications or mixing with various surfactants, and those modified with isocyanate groups blocked to prolong the pot life are mentioned. They can be used alone or in combination of two or more.

Further, in order to enhance the reaction of the isocyanate group-containing adhesive to enable a strong bond in a short time hot pressure reaction, an isocyanate group reactive substance other than water is added and allowed to react in the hot pressure pressing step. Urethane, urea, amide,
It is possible to produce burette, acyl urea, allophanate and the like. As the isocyanate group-reactive substance, various polyols (low molecular weight polyols, polyether polyols, polyester polyols, polycarbonate diols, acrylic polyols, silicone polyols, etc.) are generally used, and various polypropylene glycols (hereinafter PPG) (ethylene oxide) are used. Modified PPG,
Primary OH-modified PPG, bisphenol A modified PPG, rosin modified PPG, etc.), various polyethylene glycols, various povals, polybutadiene polyols, hydrogenated polybutadiene polyols, polytetramethylene ether glycols, polyester polyols, castor oil-based polyols, acrylic polyols, etc. In addition, 2-hydroxyethyl acrylate and compounds having an amino group (acrylic amides, urea compounds, various diamines, etc.), dibasic acids (azelaic acid, adipic acid, sebacic acid, isophthalic acid, terephthalic acid, etc.), Examples thereof include compounds having a carboxyl group such as vinyl acetate, various epoxy resin compounds, castor oil, liquid polybutadiene, active hydrogen compounds such as neoprene, and the like. It is needless to say that these can be used alone or in combination of two or more kinds.

Further, in order to accelerate the reaction of the isocyanate group-containing adhesive, reaction catalysts such as various amine compounds and organometallic compounds such as lead octylate may be appropriately added. In order to suppress the reaction before entering the hot pressing process as much as possible, the catalyst does not exhibit activity at room temperature, but it is a temperature-sensitive catalyst that exhibits activity near the pressing temperature or it is compressed so as to exert its effect in the pressing process. It is preferable that the catalyst is embedded in microcapsules that are destroyed by the above method to release the contents.

On the other hand, as an adhesive agent that exhibits secondary strength and adds strength, for example, phenol, poval, epoxy,
Starch or the like can be used alone or in combination of two or more kinds. The isocyanate group-containing adhesive also develops the secondary strength by heating and drying after the primary strength is developed. In addition, substances such as poval and starch that gel in hot water also have the function of adding primary strength. The strength of these adhesives is not expressed unless they are sufficiently heat-cured, but the laminate having the primary strength and shape maintained by the isocyanate group-containing adhesive is heated and dried in a state where it is released from the press. Thus, the secondary strength required as a building material such as a base plate or outer wall base material can be efficiently and sufficiently heat-cured.

Further, an organic silicone monomer may be added to increase the strength. Organic silicone monomers have a functional group that bonds to the surface of inorganic materials such as mineral fibers and inorganic powders, and a functional group that bonds to organic materials such as organic binders. A strong adhesive force can be created as an inclusion of an organic material.

The organosilicone monomer has the general formula YRSi
X ₃ has an organic functional group (Y) capable of binding to an organic material in one molecule, and a hydrolyzable group (X) which is hydrolyzed to generate a binding force on the surface of the inorganic material, The organic functional group (Y) is generally bonded to a silicon atom (Si) via a short chain alkyl group (R). Y is a vinyl group, methacryl group, amino group, epoxy group, mercapto group or the like, and X is a chloro group, an alkoxy group, a methoxy group, an ethoxy group, an acetoxy group or the like.

As the organic silicone monomer, γ-chloropropyltrimethoxysilane, vinyltrichlorosilane, vinyltriethoxysilane, vinyltrimethoxysilane, vinyltris (β-methoxyethoxy) silane, γ-methacryloxypropyltrimethoxysilane,
β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane,
Examples include γ-aminopropyltriethoxysilane, N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane, and γ-ureidopropyltriethoxysilane.

The addition amount of the organic silicone monomer in the upper and lower layers is 0.01 to 0.5% by weight, more preferably 0.05 to 0.5% by weight, based on the solid content of the binder. Since the upper and lower layers are wet-processed from the slurry, a paper-making additive such as a sizing agent, a coagulant, or a defoaming agent may be added if necessary. The inorganic foam forming the middle layer portion is added for weight saving while maintaining the compressive strength.For example, perlite, shirasu foam, silica flower, glass foam, vermiculite, obsidian foam, etc. Yes,
These can be used alone or in combination of two or more.

The amount of the inorganic foam added is 40% of the total amount of the middle layer.
It is preferably about 90%. This is because if it is less than 40% by weight, the desired weight reduction effect cannot be obtained, and if it exceeds 90% by weight, the ratio of the fiber and the binder becomes small and the desired compressive strength cannot be obtained. The fibrous material forming the middle layer is for connecting the inorganic foams, for example, rock wool, slag wool, mineral fibers such as glass wool, polypropylene, synthetic resin fibers such as polyester, pulp, hemp, Natural fibers such as flax and other plant fibers may be mentioned, which may be used alone or
It can be used in combination of two or more species. The content of fibrous material is
It is preferably 5 to 40% by weight of the whole inorganic intermediate layer. This is because if it is less than 5% by weight, the desired strength cannot be obtained, and if it exceeds 40% by weight, the weight reducing effect of the inorganic foam is impaired. In addition, you may use the heat-fusion fiber which also had the function as an adhesive agent as needed.

The adhesive forming the middle layer portion is added in order to bond and integrate the inorganic foam and the fibrous material. The material and the addition amount thereof are the same as those of the above-mentioned upper and lower layer portions. Therefore, the description is omitted. The isocyanate group-containing adhesive is not particularly required, but it is preferable to add it in order to develop the initial strength in the middle layer portion and further increase the strength.

Further, if necessary, an inorganic powder material used in the surface layer portion may be added to the middle layer portion. This is because these are effective in densely forming the middle layer portion and improve the nail holding force. Generally, the bending strength is improved if there is a large amount of adhesive or wood fiber or other organic fiber, but in order to obtain an inorganic plate-shaped body as a quasi-incombustible material, the total amount of organic components is 15% by weight including the binder. % Or less, and in order to obtain an inorganic plate-shaped body as a noncombustible material, the total amount of organic components including the binder needs to be 7% by weight or less.

Next, in the method for producing an inorganic plate-like material according to the present invention, the upper and lower layers are various additives such as mineral fiber, inorganic powdery material, organic fiber, organic silicone monomer, and isocyanate group-containing adhesive. Agent and other adhesives, substances that react with isocyanate groups are appropriately added to water, stirred and aggregating agents and other papermaking additives are added according to a predetermined procedure to obtain a slurry having a solid content of several%. The wet inorganic plate to be the lower layer is obtained by introducing it into a fourdrinier or round netting machine.

The material for the middle layer is obtained by mixing the inorganic foam, the fibrous material and the adhesive while spraying water. The lower layer and the middle layer are laminated by a method such as uniformly spraying, depositing and laminating this on the upper surface of the lower layer wet inorganic mat. Then,
A wet inorganic plate for the upper layer obtained separately in the same manner as the lower layer is laminated on the intermediate layer of the laminate obtained in advance, and these are hot pressed at a predetermined temperature and pressure by a hot press. The hot pressing time and temperature are set so that the added isocyanate group-containing adhesive starts the reaction, and in particular, the upper and lower layers do not cause springback after the press is opened and can maintain sufficient strength and shape. In this case, even if the water contained in the upper and lower layers remains due to insufficient drying, the upper and lower layers having sufficient strength can be obtained by the reaction of the isocyanate group-containing adhesive. This hot pressing step is preferably performed by using a continuous press made of a steel belt heated to 80 ° C to 180 ° C because the production efficiency is remarkably improved.

The thus obtained three-layered inorganic plate-like body is dried with a hot air dryer at 100 ° C. to 250 ° C., and other adhesives contained in the inorganic plate-like body, such as phenol-based adhesives, are used. By sufficiently performing the reaction of the adhesive including the dehydration condensation system, a stronger and stronger dry inorganic plate-like body is obtained. Regarding the isocyanate group-containing adhesive and the method for adding the substance that reacts with the isocyanate group, the method of aggregating with an aggregating agent after adding all as described above is preferable because the yield is also good, but other than that You may add after adding a material and adding an aggregating agent, and you may add an isocyanate group containing adhesive to the wet inorganic board obtained by the papermaking by methods, such as spraying. When it is added to the wet inorganic plate, it is preferable to suck from the lower part of the plate because the spray liquid penetrates into the inside. According to these methods, there is an advantage that it is not necessary to consider the reduction in the pot life of the isocyanate group in the slurry to which the isocyanate group-containing adhesive is added. Of course, it is also possible to add a liquid binder, a substance that reacts with an isocyanate group, an organic silicone monomer and the like in the same manner by the above-mentioned spraying method.

As a method of adding the isocyanate group-containing adhesive to the middle layer portion, for example, an inorganic foam which is a constituent of the middle layer, an appropriate amount of fibrous material and a binder are mixed under spraying of an aqueous solution containing an organic silicone monomer. To do. This has an advantage that the raw material can be prevented from scattering and can be uniformly added to the material for the intermediate layer. An adhesive substance may be interposed at the interface between the upper and lower layers and the middle layer. Thereby, the adhesive strength at the interface between the upper and lower layer portions and the middle layer portion can be increased, and various strengths such as bending strength and peeling strength can be improved. Examples of the method of interposing include spraying, spraying, and coating.

When an isocyanate group-containing adhesive is added to the adhesive to be added to the interface, the added adhesive chemically bonds with a substance that reacts with the isocyanate groups contained in the upper and lower layers or the middle layer by a hot press for a short time, A strong interfacial adhesion can be performed. In addition, if the interface contains a substance that reacts with isocyanate groups, the isocyanate group-containing adhesive contained in the surface layer and the intermediate layer and the reaction substance at the interface chemically bond in the same manner in the hot pressing process to achieve strong interface adhesion. It is more preferable because it can be performed.

Although the inorganic plate having a three-layer structure has been described above, the present invention is not limited to this, and the intermediate layer may have a plurality of layers, and an adhesive substance may be interposed at the interface between the intermediate layers. Of course, it is also good.

[0029]

Therefore, according to the present invention, by adding an isocyanate adhesive which exhibits an adhesive force promptly by hot-pressing especially in the presence of water, sufficient strength is exhibited in the inorganic plate-like body. Therefore, the hot pressing process can be completed in a short time, and the production efficiency can be improved. In particular, it is effective for manifesting the strength of the upper and lower layers, which bears the strength such as the bending strength of the multi-layered inorganic plate-shaped body.

Further, by simultaneously adding a substance that reacts with an isocyanate group, the reaction of the isocyanate group-containing adhesive can be enhanced and a stronger bond can be achieved by a hot pressing reaction in a short time, and the strength can be improved. . Further, a step of expressing primary strength by reacting the isocyanate group-containing adhesive quickly by heat-pressing the laminate of the present invention with a hot-pressing press,
The inorganic plate-like body of the present invention is hot-pressed for a short time by using the step of heat-drying the press-integrated laminated body and finally curing the adhesive and other adhesives to develop the secondary strength. And it can be efficiently produced by the subsequent drying step.

[0031]

EXAMPLES Examples according to the present invention will be described below. (Example 1) 46% by weight of rock wool as a mineral fiber, 2% by weight of pulp as an organic fiber, 40% by weight of calcium carbonate as an inorganic powder, 6% by weight of powdered phenol as an adhesive, 4% by weight of starch, And 1.5% by weight of an isocyanate group-containing adhesive (polymeric MDI) and 0.015% by weight of γ-aminopropyltriethoxysilane as an organic silicone monomer were mixed by stirring in water, and an appropriate amount of an aggregating agent was added to cause aggregation. After that, papermaking is carried out and the mat for upper and lower layers is 2
I made one.

As the material for the middle layer, 66% by weight of pearlite as an inorganic foam and calcium carbonate as an inorganic powder 2
1% by weight, 3% by weight of pulp as an organic fiber, 6% by weight of powdered phenol as an adhesive, and 4% by weight of starch were uniformly mixed while spraying water. The material for the middle layer is uniformly spread and deposited on the wet mat as the lower layer so as to have a thickness of 30 mm, and the wet mat as the upper layer is further stacked thereon to obtain a laminate having a thickness of about 38 mm. After pressing this with a hot press at 95 ° C for 5 minutes (distance bar 8 mm),
It was dried with a hot air dryer at 190 ° C. for 30 minutes to obtain an inorganic plate-like body having a three-layer structure in a completely dry state.

The thickness of the prepared inorganic plate-like body was 8.4 mm and the specific gravity was 0.73. The weight ratio of the three layers was as follows:
Middle layer: lower layer = 2: 2.5: 2. The physical property measurement results are shown in Table 1. As an example, the measurement result of the specific gravity distribution of the cross section is shown in FIG. (Example 2) 46% by weight of rock wool as a mineral fiber, 2% by weight of pulp as an organic fiber, 40% by weight of calcium carbonate as an inorganic powder, 6% by weight of powdered phenol as an adhesive, 4% by weight of starch, 0.015% by weight of γ-aminopropyltriethoxysilane as an organic silicone monomer was stirred and mixed in water, and an appropriate amount of an aggregating agent was added to the aggregated slurry to obtain 1.5% by weight of an isocyanate group-containing adhesive (polymeric MDI). Add to the emulsion as it is dispersed, stir it thoroughly, and then make a sheet to make a mat for upper and lower layers.
I made one.

As the material for the intermediate layer, 66% by weight of pearlite as an inorganic foam and calcium carbonate as an inorganic powder 2
1% by weight, 3% by weight of pulp as an organic fiber, 6% by weight of powdered phenol as an adhesive, and 4% by weight of starch were uniformly mixed while spraying water. The material for the middle layer is uniformly spread and deposited on the wet mat as the lower layer so as to have a thickness of 30 mm, and the wet mat as the upper layer is further stacked thereon to obtain a laminate having a thickness of about 38 mm. After pressing this with a hot press at 95 ° C for 5 minutes (distance bar 8 mm),
It was dried with a hot air dryer at 190 ° C. for 30 minutes to obtain an inorganic plate-like body having a three-layer structure in a completely dry state.

The thickness of the prepared inorganic plate-like body was 8.6 mm and the specific gravity was 0.73. The weight ratio of the three layers was as follows:
Middle layer: lower layer = 2: 2.5: 2. The physical property measurement results are shown in Table 1. Comparative Example 1 Rock wool 46% by weight as mineral fiber, pulp 2% by weight as organic fiber, calcium carbonate 40% by weight as inorganic powder, powdered phenol 8% by weight, starch 4% by weight, 0.015% by weight of γ-aminopropyltriethoxysilane as an organic silicone monomer was stirred and mixed in water, and a slurry containing an appropriate amount of a flocculant was added to prepare a slurry to prepare two upper and lower layer mats.

As the material for the middle layer, 66% by weight of pearlite as an inorganic foam and calcium carbonate as an inorganic powder 2
1% by weight, 3% by weight of pulp as an organic fiber, 6% by weight of powdered phenol as an adhesive, and 4% by weight of starch were uniformly mixed while spraying water. The material for the middle layer is uniformly spread and deposited on the wet mat as the lower layer so as to have a thickness of 30 mm, and the wet mat as the upper layer is further stacked thereon to obtain a laminate having a thickness of about 38 mm. After pressing this with a hot press at 95 ° C for 5 minutes (distance bar 8 mm),
It was dried with a hot air dryer at 190 ° C. for 30 minutes to obtain an inorganic plate-like body having a three-layer structure in a completely dry state.

The thickness of the prepared inorganic plate-like material was 9.1 mm and the specific gravity was 0.72. The weight ratio of the three layers was as follows:
Middle layer: lower layer = 2: 2.5: 2. The physical property measurement results are shown in Table 1. The bending strength was measured according to JIS A1408, and the nail side surface resistance was measured according to ASTM D-1037. The specific gravity distribution was measured with a density profiler.

[0038]

[Table 1]

Although the specific gravity was set to be substantially the same in Examples 1 and 2 and Comparative Example 1, the upper and lower layers of Comparative Example 1 caused a slight springback, the specific gravity was slightly decreased, and the bending strength was decreased in Example 1. 22-29% and nail side resistance by 27-36% were reduced compared to 2, and the strength was improved by using an adhesive containing an isocyanate group. In addition, in Example 2, since the adhesive containing an isocyanate group was added after the coagulant was added, the yield was lower and the strength was lower than in Example 1, but practically sufficient strength was obtained. is doing.

Example 3 Rock wool 45.5% by weight as mineral fiber, pulp 2% by weight as organic fiber, calcium carbonate 40% by weight as inorganic powder, and powdered phenol 6 as adhesive.
% By weight, starch 4% by weight, 0.015% by weight of γ-aminopropyltriethoxysilane as an isocyanate organic silicone monomer, a substance capable of reacting with an isocyanate group (polypropylene glycol: molecular weight 400) 1
% By weight and 1.5% by weight of an isocyanate group-containing adhesive (polymeric MDI) in water, the mixture was stirred and mixed, and an appropriate amount of a coagulant was added, and after coagulation, papermaking was performed to prepare two mats for upper and lower layers.

As the material for the middle layer, 66% by weight of pearlite as an inorganic foam and calcium carbonate as an inorganic powder 2
1% by weight, 3% by weight of pulp as an organic fiber, 6% by weight of powdered phenol as an adhesive, and 4% by weight of starch were uniformly mixed while spraying water. The material for the middle layer is uniformly spread and deposited on the wet mat as the lower layer so as to have a thickness of 30 mm, and the wet mat as the upper layer is further stacked thereon to obtain a laminate having a thickness of about 38 mm. After pressing this with a hot press at 95 ° C for 5 minutes (distance bar 8 mm),
It was dried with a hot air dryer at 190 ° C. for 30 minutes to obtain an inorganic plate-like body having a three-layer structure in a completely dry state.

The prepared inorganic plate-like body had a thickness of 8.6 mm and a specific gravity of 0.73, and the weight ratio of the three layers was as follows:
Middle layer: lower layer = 2: 2.5: 2. The physical property measurement results are shown in Table 2. Table 2 shows the result of separating only the surface layer from the three-layered product and measuring its specific gravity. [Example 4] 46% by weight of rock wool as a mineral fiber, 2% by weight of pulp as an organic fiber, 40% by weight of calcium carbonate as an inorganic powder, 6% by weight of powdered phenol as an adhesive, 4% by weight of starch, 0.015% by weight of γ-aminopropyltriethoxysilane as an isocyanate organic silicone monomer, and 1.5% by weight of an isocyanate group-containing adhesive (polymeric MDI) are mixed by stirring in water, and an appropriate amount of a flocculant is added, and after coagulation Two sheets of mats for upper and lower layers were prepared by papermaking. While suctioning this mat from the bottom under reduced pressure, a 2% aqueous solution of a substance (polypropylene glycol: molecular weight 400) capable of reacting with an isocyanate group on the upper surface is polypropylene mat mat composition weight (dry weight conversion)
It was sprinkled so that it would be 1.5% by weight, and was sufficiently impregnated into the papermaking mat.

As a material for the middle layer, 66% by weight of pearlite as an inorganic foam and calcium carbonate as an inorganic powder 2
1% by weight, 3% by weight of pulp as an organic fiber, 6% by weight of powdered phenol as an adhesive, and 4% by weight of starch were uniformly mixed while spraying water. The material for the middle layer is uniformly spread and deposited on the wet mat as the lower layer so as to have a thickness of 30 mm, and the wet mat as the upper layer is further stacked thereon to obtain a laminate having a thickness of about 38 mm. After pressing this with a hot press at 95 ° C for 5 minutes (distance bar 8 mm),
It was dried with a hot air dryer at 190 ° C. for 30 minutes to obtain an inorganic plate-like body having a three-layer structure in a completely dry state.

The thickness of the prepared inorganic plate-like material was 8.6 mm and the specific gravity was 0.73. The weight ratio of the three layers was as follows:
Middle layer: lower layer = 2: 2.5: 2. The physical property measurement results are shown in Table 2. In addition, Table 2 shows the results of separating only the upper and lower layers from the three-layer constitution product and measuring the specific gravity thereof.

[0045]

[Table 2]

The difference between Example 1 and Examples 3 and 4 is that in Examples 3 and 4, in addition to the isocyanate group-containing adhesive (polymeric MDI) in the upper and lower layers, a substance capable of reacting with an isocyanate group (polypropylene glycol- It was found that the flexural strength was improved by a small amount of 7.1 to 9.8%. Also,
The specific gravity of the upper and lower layers is increased by 2.8 to 5.5% compared to Example 1 in which the polymeric MDI alone is added.
It is considered that Examples 3 and 4 have improved bending strength as compared with Example 1.

In Example 4, the mat for the upper and lower layers was formed and then impregnated with a substance capable of reacting with an isocyanate group. The yield and the strength were lower than those in Example 3, but in practical use. Has sufficient strength.

[0048]

As is apparent from the above description, according to the method for producing an inorganic plate-like body according to the present invention, the isocyanate group-containing adhesive can be subjected to a short hot-pressing step. It reacts quickly with hot water, and at least the upper and lower layers are firmly bound to each other to express the primary strength, so that it can be handled such as transported while maintaining its shape, and further contains a substance capable of reacting with an isocyanate group. By doing so, the reaction of the isocyanate group-containing adhesive is enhanced to enable a stronger bond.

By carrying out the final drying step in a dryer without a press, the adhesive is hardened and the secondary strength is developed, so that the practical strength as a building material such as a base plate or outer wall base material is obtained. It is possible to obtain an inorganic plate-shaped body having excellent fire resistance. In particular, when the hot-pressing process for a short time is performed by the continuous hot-pressing and the line is configured to continuously feed the hot-air dryer, it is possible to extremely efficiently produce a high-strength inorganic plate-like body having a desired strength. it can.

[Brief description of drawings]

FIG. 1 is a sectional specific gravity distribution diagram in a thickness direction of an inorganic plate-shaped body according to Example 1.

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Claims (2)

(57) [Claims] 1. Mainly composed of mineral fibers and inorganic powders,
A step of paper-making a wet inorganic plate to be a lower layer part from a slurry obtained by adding an adhesive containing at least an isocyanate group to water, and mainly comprising an inorganic foam on the lower layer part,
A step of laminating a middle layer portion formed by adding a fibrous material and an adhesive, and a mineral fiber, an inorganic powdery substance as a main component, and an upper layer portion from a slurry obtained by adding an adhesive containing at least an isocyanate group to water A step of forming a wet inorganic plate to be laminated on the middle layer part to obtain a laminate, and heat-pressing the laminate with a hot press to cause the isocyanate group-containing adhesive to react with water. From the step of generating urea to generate primary strength, and the step of heat-drying the pressure-integrated laminated body to finally cure the isocyanate group-containing adhesive and other contained adhesives to generate secondary strength. And a method for producing an inorganic plate-shaped body. 2. The method for producing an inorganic plate-shaped body according to claim 1, wherein a substance that reacts with an isocyanate group of an isocyanate group-containing adhesive is used as an upper layer portion and a lower layer portion, or papermaking from the slurry. A method for producing an inorganic plate-like body, which comprises adding to the obtained wet inorganic plate.