JP5016221B2 - Manufacturing method of building board and building board - Google Patents

Description

  The present invention relates to a method for manufacturing a building board to which inkjet coating has been applied, and the building board.

  Cement-based building boards are widely used for building exterior materials such as outer wall materials, roofing materials and roofing materials. Since such a building board bears the formation of the external appearance of a building, technical examination is added about the surface decoration which implement | achieves various designs. For example, the surface of a wet sheet produced by, for example, making an aqueous slurry is generally subjected to press forming or the like, followed by curing and curing, and then coating the surface of the uneven pattern. .

As one method of coating, recently, inkjet coating has been conceived in which a coating is sprayed from an inkjet nozzle head in synchronization with the substrate transport speed toward the surface of the substrate transported on a conveyor. Such ink-jet coating enables local and position-controlled coating as compared with a coating roll or the like that has been generally used so far. Therefore, there is an advantage that a building board coated with a high design with a natural texture can be manufactured by expressing dark and light.
JP 2004-17007 A

  However, with the recent increase in demand for high designability of building boards, it has been demanded to give higher designability to building boards that have been subjected to inkjet coating.

  In addition, when ink-jet coating is applied to the building board as described above, it is common to apply ink-jet coating in a state in which familiarity of the ink is increased by forming a porous receiving layer in advance. If such a receiving layer is provided, it becomes difficult to impart high water permeability resistance without deteriorating the ink receiving performance.

  The present invention has been made in view of the above points, and can impart higher designability to a building board that has been subjected to inkjet coating, and can also improve the water resistance of the building board. It aims at providing the manufacturing method of a building board, and the building board manufactured by this method.

In the method for producing a building board according to the present invention, a dry or semi-dried powdery surface material mainly composed of cement is spread on the surface of a wet sheet obtained by molding a cement-based slurry, and the thickness is 10 A surface layer of ˜50 mm is formed, and the surface on which the surface layer is formed is pressed with a pressing pressure in the range of 1 to 20 MPa to form a concavo-convex pattern and the surface layer has a thickness of 0.5 to 5 mm. After the density is set in the range of 0.9 to 1.40 g / cm ³ , curing is performed, and after forming a receiving layer on the surface of the obtained inorganic plate, inkjet coating is performed. Since the surface layer is highly compressed, it is easy to form a deep uneven pattern, and the water absorption and water permeability of the surface layer are low.

  As the surface material, a material to which a water repellent is added can be used. In this case, the water absorption and water permeability of the surface layer are further reduced.

  A silane water repellent can be used as the water repellent. In this case, the water absorption and water permeability of the surface layer are further reduced.

  Moreover, the building board which concerns on this invention is manufactured by the above methods, It is characterized by the above-mentioned.

  According to the present invention, a deep concavo-convex pattern can be formed on a cement-based building board and a highly designable pattern can be expressed on the surface by ink jet coating. Moreover, since the water absorption and water permeability of a surface layer are low, the water permeability resistance of a building board can be improved.

  Hereinafter, the best mode for carrying out the present invention will be described.

  A wet sheet (green sheet) mainly composed of cement and reinforcing fibers can be used for the production of the inorganic board that is the base of the building board. This wet sheet can be made by various papermaking methods such as a long-mesh type and a round-net type using a cement-based aqueous slurry as a raw material composition, but an appropriate method such as extrusion molding may be adopted. it can. Examples of the raw material composition include hydraulic cement components of 30 to 95% by mass, fillers such as silica, silica powder, and fly ash 2 to 60% by mass, and reinforcing fibers such as pulp 3 to 10% by mass. A slurry having a solid content of about 50 to 2000 parts by mass with respect to 100 parts by mass of the solid can be used. In addition, as a cement component, what adjusted composition suitably, such as normal Portland cement and blast furnace cement, can be used. As the reinforcing fiber pulp, softwood pulp, hardwood pulp, recycled waste paper (waste paper pulp), or a mixture of two or more of these can be used.

  A surface layer is formed on the green sheet by laminating a dry or semi-dry surface material mainly composed of cement and reinforcing fibers on the wet sheet. As the surface material, the same material as in the case of the wet sheet can be used. For example, it is possible to use a mixture in which water is blended in a solid content composed of 30 to 95% by mass of a cement component, 2 to 60% by mass of a filler, and 3 to 10% by mass of a reinforcing fiber, and mixed with a mixer. As the filler, a lightweight aggregate such as pearlite may be used.

  Furthermore, as a solid component on the surface of the base material, a portion removed as an unnecessary portion when a cement-type outer wall material is produced may be crushed and used. When such a reused product is used for the surface material, resources can be effectively used.

  When spraying a semi-dry surface material, it is preferable that the wet sheet has a moisture content of 50 to 200% by mass, and the semi-dry type surface material has a moisture content of 5 to 50% by mass. .

  Moreover, various means can be employ | adopted for dispersion | distribution of the said surface material.

  After forming the two-layer material in this way, the uneven surface pattern can be formed by performing press molding on the surface on which the surface material is dispersed. At this time, by spraying the dry or semi-dry surface material as compared with the case of only the green sheet, the compressibility of the material is improved and the pattern reproducibility at the time of molding is increased.

After forming the surface layer in this way, in performing press molding, the surface material is dispersed so that the thickness of the surface layer formed by the dispersion of the surface material is in the range of 10 to 50 mm, and after the surface layer is formed The press pressure during press molding is in the range of 1 to 20 MPa, the thickness of the surface layer after this pressing is in the range of 0.5 to ⁵ mm, and the density of the surface layer is in the range of 0.9 to 1.40 g / cm ³ . To be. As a result, the surface layer can be highly compressed to form a pattern with high pattern reproducibility, and a high design can be imparted to the building board. In addition, the surface layer is formed densely in this way. Thus, the water absorption and water permeability can be reduced, and the water absorption and water permeability of the entire building board can be reduced despite the formation of a receiving layer as described later.

  Further, if a surface material to which a water repellent is added is used as the surface material for forming the surface layer, the water absorption and water permeability of the surface layer can be further reduced. As the water repellent, for example, a silicone water repellent can be used, and an alkoxysilane water repellent having a structure having an alkoxyl group is particularly preferable.

  Examples of the alkoxysilane water repellent include those having a medium chain or long chain alkyl group as a functional group, such as those represented by the following general formula (1) and the following general formula (2). Can be mentioned.

R _n Si (OR ¹ ) _4-n (1)
In the general formula (1), n represents an integer of 1 to 3, R represents a medium chain or long chain alkyl group, and R ¹ represents an alkyl group.

R _n Si (OR ¹ ) _4-nm X _m (2)
In general formula (2), n is an integer of 1 to 3, m is an integer of 0 to 2, R is a medium chain or long chain alkyl group, R ¹ is an alkyl group, and X is a hydrolyzable group. Respectively.

  As such an alkoxysilane water repellent, in addition to those composed of monomer molecules, those composed of oligomers obtained by polycondensation of a plurality of molecules by hydrolysis can also be used.

Here, as the medium-chain or long-chain alkyl group (R), a linear or branched alkyl group having 4 to 12 carbon atoms is exemplified as a preferable one. Also, normally the alkyl group constituting the alkoxy group (OR ^₁₎ (R ₁₎ is preferably a lower alkyl group having about 1-3 carbon atoms. Moreover, about a hydrolysable group, an alkoxy group, ester group, a halogen atom, etc. can be mentioned.

  Such alkoxysilane water repellents having a medium chain or long chain alkyl group as a functional group can interact with each other in the presence of water or with cement components and aggregate components in the surface material to be dispersed. The reaction is considered to give the required low water absorption to the surface of the inorganic plate. Regarding the reaction in this case, depending on the type and amount of the water repellent used, the composition of the surface material, etc., as a guide, the reaction is in the range of 20 to 100%, preferably in the range of about 50 to 90%. It is considered to be a rate.

  Considering such a reaction rate, the alkoxysilane water repellent is preferably used as an oligomer by hydrolysis.

  Further, as described above, the functional group alkyl group of the alkoxysilane water repellent is preferably a medium chain or long chain alkyl group having 4 to 12 carbon atoms, and in the case of a lower alkyl group having 1 to 3 carbon atoms. Is difficult to obtain a good water-absorbing effect, and the same applies when the carbon number exceeds 12.

  The amount of such water repellent added is preferably in the range of 0.05 to 5.0% by weight with respect to the surface material. If the amount is less than 0.05% by weight, the effect of reducing the water absorption on the surface is not sufficient. On the other hand, if it is added in an amount exceeding 5.0% by weight, the efflorescence in the pre-acceleration curing is caused by excessively low water absorption. It becomes difficult to suppress the occurrence.

  Moreover, although such a water repellent may add only a monomer or an oligomer, it is preferable to add to a surface material in the emulsion state previously mixed with water. Thereby, the water repellent can be uniformly dispersed in the surface material.

Regarding the addition of the water repellent to the surface material, the material composition of the wet sheet, the type of the water repellent taking into account its moisture content, the amount added, and the mixing ratio with water are selected. Although the surface water absorption of the building board as a product can be controlled by this selection, these conditions are preferably selected so that the surface water permeability value after curing and curing is 5000 g / m ² or less. Here, a building board having a large surface water permeability value exceeding 5000 g / m ² may have to be additionally subjected to waterproofing in a subsequent process.

  After such press molding, the green sheet on which the surface layer of the surface material is laminated is cured and cured. At this time, it is desirable to perform autoclave curing, and the temperature at that time is preferably 140 ° C. or higher. In practice, it is desirable that the curing is a two-stage curing of an autoclave curing and a pre-acceleration curing preceding this, that is, a pre-curing in which steam is added for heating. Thereby, sufficient strength can be obtained for the inorganic plate, and the structure and performance can be made uniform.

  When curing this molded body, a sealer may be applied to the surface of the surface layer before curing, but since the water absorption and water permeability of the surface layer are reduced as described above, waterproofing in a later step is required. There is no need to perform this additionally, and the manufacturing process can be simplified.

  However, the water permeability of the building board may be further improved by applying a sealer. In this case, the sealer is not particularly limited. For example, an acrylic emulsion paint can be used, but an aqueous emulsion paint such as urethane, silicon, or fluorine can also be used.

  The coating method of the sealer is not particularly limited, and commonly used coating methods such as rolls, sprays and showers can be applied. For example, the coating can be performed by roll coating, or when spray coating is further applied, it is particularly deep. Even when the concave / convex pattern is formed and the whole cannot be painted only by roll coating, it is preferable that the entire coating can be performed.

  When applying such a sealer, it is performed after spraying the surface material and before curing, but when performing pre-acceleration curing as described above, the sealer is applied after pre-acceleration curing, and then the autoclave is applied. When the curing is performed, the sealer can be applied to the base material whose handling is improved by the pre-acceleration curing, so that the coating property of the sealer is improved and the application efficiency is increased.

After curing and curing, a receiving layer is laminated and formed on the side where the surface layer of the obtained inorganic plate is formed. The receiving layer has a function of fixing ink applied at the time of inkjet coating without bleeding, and has a property of absorbing ink, for example, a porous layer having water absorption. Specifically, for example, by using a water-based paint blended with at least one of an inorganic filler and a hygroscopic resin, and applying it by spraying, the film is dried by heating at 100 to 200 ° C. for 30 seconds or more to form a film. A receiving layer can be formed. This thickness of the receiving layer is not particularly limited, it is preferable to be in the range of 30 to 200 g / m ² at a wet coating weight.

  After forming the receiving layer, ink jet coating is applied to the surface of the receiving layer.

  As a coating apparatus used for performing inkjet coating, the one shown in FIG. 1 can be exemplified. This coating apparatus controls the coating nozzle head 8 provided with the spray nozzle 10, the paint supply tank 9 that supplies the paint to the spray nozzle 10 of the paint nozzle head 8, and the spray of paint from the spray nozzle 10 of the paint nozzle head 8. The ink jet type coating machine 12 provided with the coating control system 11 and the like, and the transport means 7 for transporting the inorganic plate 1 are formed.

  The coating nozzle head 8 is provided at the lower end of the ink jet coating machine 12 and is formed as a long line head in a direction perpendicular to the feeding direction of the building board 1.

  The coating nozzle head 8 is formed of four types of coating nozzle heads 8y, 8c, 8m, and 8k that eject paints of yellow, cyan, magenta, and black, so that full-color printing can be performed. is there. The number of coating nozzle heads 8 is not limited to this, and a number corresponding to the type of ink used is provided. Similarly, the paint supply tank 9 is also composed of four types. The paint supply tank 9y for supplying yellow paint is applied to the coating nozzle head 8y, and the paint supply tank 9c for supplying cyan paint is applied to the coating nozzle head 8c. The paint supply tank 9m for supplying magenta paint is connected to the paint nozzle head 8m, and the paint supply tank 9k for supplying black paint is connected to the paint nozzle head 8k. The coating nozzle heads 8y, 8c, 8m, and 8k are arranged along the transport direction of the inorganic plate 1.

  The painting control system 11 includes various CPUs, ROMs, RAMs, and the like, and includes a painting data creation unit, a painting control unit, an injection nozzle control unit, and the like. The painting data creation unit inputs and stores the color pattern data obtained by scanning the original image with a scanner or the like, and the painting control unit paints the color pattern data corresponding to the building board 1 to be painted. A control signal is output from the data creation unit to the ejection nozzle control unit based on the color pattern data. The spray nozzle control unit is connected to each spray nozzle 10 of the coating nozzle heads 8y, 8c, 8m, and 8k, and controls each spray nozzle 10 based on a control signal input from the spray nozzle control unit. . Each ejection nozzle 10 is controlled to be ejected by, for example, a piezo control system or a control system for irradiating a photothermal exchange element with laser light. By controlling each ejection nozzle 10 with an ejection nozzle control unit, It is possible to perform painting by full-color printing corresponding to the color pattern by individually controlling the spraying and stopping of the cyan, magenta, and black paints.

  The conveying means 7 can be formed by a belt conveyor 7 a in which an endless belt 13 such as a timing belt is suspended between pulleys 14, and a transport surface 6 constituted by the upper surface of the endless belt 13 is an ink jet coating machine 12. It is arranged on the lower side.

  In carrying out the inkjet coating, first, the inorganic plate 1 is supplied to the conveying means 7. At this time, the plurality of inorganic plates 1 can be sequentially conveyed at intervals.

  Thus, the inorganic board 1 conveyed by the conveying means 7 passes below the coating nozzle head 8. At this time, ink is ejected from the coating nozzle head 8 toward the receiving layer on the inorganic board 1 by an ink jet method to be painted, and the building board 1 with a design pattern is obtained.

  By such inkjet coating, a desired design pattern can be expressed on the building board 1. In addition, by performing such ink jet coating, it is possible to perform position-controlled coating, for example, coating that matches a recess formed in the receiving layer. In addition, high-design painting with a natural texture can be achieved by shading expression, sharp or soft expression, and the like. At this time, the ink enters the receiving layer and is fixed, whereby a clear design pattern is given.

  At this time, since it is possible to form a deep concavo-convex pattern on the inorganic board as described above, by applying ink-jet coating to this, a design pattern having a remarkably high design property can be expressed in combination with the deep concavo-convex pattern. It is something that can be done. In addition, since application by ink-jet coating is performed, a desired design pattern can be expressed over the entire surface without leaving uncoated areas on the convex portions and concave portions of the inorganic plate having a deep concavo-convex pattern.

Next, if necessary, a clear layer for surface protection is formed on the surface of the receiving layer that has been subjected to inkjet coating. The clear layer can be formed by applying and forming an appropriate clear paint. For example, an acrylic emulsion or the like is used, and this is applied by spraying and then heated at 100 to 200 ° C. for 30 seconds or more. A clear layer can be formed by drying to form a film. The thickness of this clear layer is not particularly limited, but it is preferable that the wet coating amount be in the range of ²⁰ to 200 g / m2.

It is also preferable to form an inorganic coating layer on the surface of the clear layer. The inorganic paint layer is a layer necessary for improving the durability such as weather resistance of the building board, and is a coating film composed of a SiO ₂ skeleton, which contains an ultraviolet absorber and, in some cases, a matting agent. It consists of a coated film. For example, it can be formed with a coating composition described in Japanese Patent No. 3242442 and Japanese Patent No. 3193382, or an inorganic coating agent described in Japanese Patent Laid-Open No. 9-249822.

Specific examples of the inorganic coating material include the coating composition described in Japanese Patent No. 3242442. That is,
(A) General formula (I)
R ¹ _n SiX _4-n (I)
Wherein R ¹ is the same or different, alkyl group, cycloalkyl group, alkenyl group, halogen-substituted hydrocarbon group, γ-methacryloxypropyl group, γ-glycidoxypropyl group, 3,4-epoxycyclohexylethyl. A monovalent hydrocarbon group having 1 to 8 carbon atoms selected from the group consisting of a group and a γ-mercaptopropyl group, n is an integer of 0 to 3, X is an alkoxy group, an acetoxy group, an oxime group, an enoxy group, A hydrolyzable group selected from the group consisting of an amino group, an aminoxy group, and an amide group.) In a colloidal silica dispersed in an organic solvent or water, A silica-dispersed oligomer solution of organosilane obtained by partial hydrolysis under the condition of using 0.001 to 0.5 mol,
(B) Average composition formula (II)
R ² _a Si (OH) _b O _{(4-ab) / 2} (II)
Wherein R ² is the same or different, alkyl group, cycloalkyl group, alkenyl group, halogen-substituted hydrocarbon group, γ-methacryloxypropyl group, γ-glycidoxypropyl group, 3,4-epoxycyclohexylethyl. A monovalent hydrocarbon group having 1 to 8 carbon atoms selected from the group consisting of a group and a γ-mercaptopropyl group, wherein a and b are 0.2 ≦ a ≦ 2, 0.0001 ≦ b ≦ 3, a + b, respectively. <A number satisfying the relationship of 4), and a polyorganosiloxane containing 1 to 30 mol% of phenyl groups based on the total R ² groups in R ² in the component, and
(C) The catalyst which accelerates | stimulates the condensation reaction of (A) component and (B) component is made into an essential component, Silica is contained as 5 to 95weight% in solid content in (A) component, At least of hydrolyzable organosilane 50 mol% is an organosilane having n = 1, and the coating composition is composed of 99 to 1 part by weight of component (B) per 1 to 99 parts by weight of component (A).

And when forming an inorganic coating layer, the inorganic board 1 in which the clear layer was formed is heated beforehand at 40 degreeC or more, and it can carry out by apply | coating an inorganic coating using a spray gun in this state. . At this time, it is preferable that drying conditions are 100-200 degreeC and 1 to 5 minutes. If the baking and drying are not sufficiently performed, depending on the temperature and humidity conditions, the durability performance of the inorganic coating layer may not be exhibited, and the performance of the photocatalyst coating layer described later may not be sufficiently obtained. In forming the inorganic coating layer, it is preferable to apply the inorganic coating to the surface of the clear layer at a coating amount of 4 to 40 g / m ² · dry. If the coating amount is less than 4 g / m ² · dry, durability such as weather resistance may not be sufficiently obtained. Conversely, if the coating amount is more than 40 g / m ² · dry, the curing shrinkage is large. There is a risk of cracks and the like.

Furthermore, in the present invention, it is preferable to form a photocatalytic coating layer on the surface of the inorganic coating layer. The photocatalyst coating layer has super hydrophilicity and is a layer necessary for improving the antifouling property of the building board. The photocatalyst paint layer is a coating film composed of a SiO ₂ skeleton and is a photocatalyst, and in some cases, matte. It consists of a coating film containing an agent. For example, it can be formed with an antibacterial inorganic paint described in Japanese Patent No. 2776259 or “Fressera PS1000” manufactured by Matsushita Electric Works Co., Ltd.

In forming the photocatalyst paint layer, the inorganic plate 1 on which the inorganic paint layer is formed is preheated to 40 ° C. or higher, and in this state, the photocatalyst paint layer forming paint is applied using a spray gun. be able to. Thus, by heating the inorganic board 1 beforehand, the energy in the drying process after forming the photocatalyst coating layer can be kept small. Moreover, when forming a photocatalyst coating layer, it is preferable to apply | coat the coating material for photocatalyst coating layer formation with the application quantity of 0.5-5 g / m < ² > * dry on the surface of an inorganic coating layer. If the coating amount is less than 0.5 g / m ² · dry, the antifouling property may not be obtained sufficiently. Conversely, if the coating amount is more than 5 g / m ² · dry, the building board becomes milky white. , There is a risk that the designability is reduced.

  When the inorganic coating layer is formed on the surface of the clear layer in this way, durability such as weather resistance can be obtained. In addition, dirt such as organic matter adhering to the surface of the building board is decomposed by the photocatalytic action of the photocatalyst paint layer, and the photocatalyst paint layer exhibits super hydrophilicity, so that the decomposed dirt is easily removed by rainwater or the like. Therefore, the antifouling property of the building board can be obtained high.

  The building board obtained as described above can impart a very excellent design property to a building by using it as an exterior material or an inner layer material of a building.

Example 1
60 parts by weight of a solid composition having a composition of 40% by weight of ordinary Portland cement, 40% by weight of quartzite powder, 5% by weight of pulp, and 15% by weight of other fillers is mixed with 540 parts by weight of water to form a slurry. Was made into a wet sheet (green sheet) having a thickness of 30 mm.

  In addition, a surface material composed of a solid component having the same composition as described above, and an addition amount of a silane water repellent oligomer (manufactured by Toray Dow Corning Co., Ltd., product number “Z6288”) to the surface material is shown in Table 1 The surface material was made to have a moisture content of 25% and dispersed on the upper surface of the green sheet to form a surface layer having a thickness shown in Table 1 below.

  Next, the surface on which the surface layer was formed was subjected to depressing press molding using a die having a convex part (height 5 mm, convex part angle angle 120 °) at a pressing pressure shown in Table 1 below, and the unevenness having a depth of 5 mm. While forming a pattern, the surface layer after pressing was shown in Table 1 below.

  Then, after pre-acceleration curing at 80 ° C. for 24 hours in a humid atmosphere, the mixture was sealed and autoclaved at 170 ° C. for 12 hours.

Next, the surface layer-formed surface is sprayed with a composition in which porous silica is blended in an acrylic emulsion and applied so that the wet coating amount becomes 100 g / m ^2, and then heated and dried at 150 ° C. for 60 seconds. A receiving layer was formed by forming a film.

  Next, the surface of the receiving layer was subjected to inkjet coating using an aqueous ink and an inkjet coating apparatus (product number “MMP13000”) manufactured by Mastermind Co., Ltd.

Next, a clear paint made of an acrylic emulsion is sprayed on the coated receiving layer surface to apply a wet coating amount of 100 g / m ^2, and then dried by heating at 150 ° C. for 60 seconds. As a result, a clear layer was formed.

  Next, an inorganic coating layer was formed on the surface of the clear layer with the coating agent of Example 1 described in Japanese Patent No. 3242442.

  That is, the A component and the B component are prepared as follows, and the A component, the B component, and the C component (N-β-aminoethyl-γ-aminopropylmethyldimethoxysilane) in a weight ratio of A: B: By blending at a ratio of C = 70: 30: 1, a coating material for forming the inorganic coating layer was obtained.

(Preparation of component A)
In a flask equipped with a stirrer, heating jacket, condenser and thermometer, methanol-dispersed colloidal silica sol MA-ST (particle size 10-20 mμ, solid content 30%, manufactured by Nissan Chemical Industries, Ltd.) 100 parts, methyltrimethoxysilane 68 parts Then, 10.8 parts of water was added, and the mixture was stirred and stirred at a temperature of 65 ° C. for about 5 hours, followed by cooling to obtain component (A). This had a solid content of 36% when left at room temperature for 48 hours. The preparation conditions of the component (A) obtained here were as follows.
-Number of moles of water per mole of hydrolyzable group: 4 × 10 ^-1
-Silica content of component (A): 47.3%
-Mol% of hydrolyzable organosilane with n = 1: 100 mol%
(Preparation of component B)
In a flask equipped with a stirrer, a heating jacket, a condenser, a dropping funnel and a thermometer, 209 parts (0.95 mol) of methyltriisopropoxysilane, 10.575 parts (0.05 mol) of phenyltrichlorosilane, and 150 parts of toluene The mixture was measured and 150 parts of water was added dropwise to the mixture in 20 minutes to hydrolyze methyltriisopropoxysilane. Stirring was stopped 40 minutes after the dropping, the lower layer water / isopropyl alcohol mixed solution containing a small amount of hydrochloric acid separated into two layers was separated, and the remaining toluene resin solution hydrochloric acid was removed by washing with water. Toluene was removed under reduced pressure and diluted with toluene to obtain a 40% toluene solution of silanol group-containing organopolysiloxane having an average molecular weight of about 2000. This was designated as component B.

And after apply | coating this coating material by spraying, it heated and dried at 150 degreeC for 7 minute (s), and it formed the film by forming the inorganic coating layer whose dry coating-film amount is 7 g / m < ² >.

Next, a photocatalyst-containing ceramic paint (manufactured by Matsushita Electric Industrial Co., Ltd., product number “PS1000”) is sprayed onto the surface of the inorganic paint layer, and then heated and dried at 150 ° C. for 1 minute to form a film. Formed a photocatalyst layer of 0.7 g / m ² . This gave a building board.

(Example 2)
A building board was obtained in the same manner as in Example 1 except that the surface material was not added with a water repellent and that the surface layer formation and pressing conditions were changed to those shown in Table 1 below. .

(Example 3)
A building board was obtained in the same manner as in Example 1 except that the surface layer formation and pressing conditions were changed to those shown in Table 1 below.

Example 4
As a water repellent, a silane water repellent (product number “Dry Seal S” manufactured by Toray Dow Corning Co., Ltd.) is added to the surface material, and the surface layer formation and pressing conditions are shown in Table 1 below. A building board was obtained in the same manner as in Example 1 except that the board was changed.

(Comparative Example 1)
In Comparative Example 1, the surface material was not added with a water repellent, and the same construction as in Example 1 except that the surface layer formation and pressing conditions were changed to those shown in Table 1 below. I got a plate.

(Evaluation test)
About each Example and the comparative example, the pattern reproducibility was evaluated by observing the uneven | corrugated pattern formed by the spin-drying | dehydration press molding visually, and evaluating the mold transfer property to the sheet | seat at the time of press molding. At this time, when there is a crack, it is evaluated as “×”, when there is a slight crack, “△”, when there is no crack but the edge is obtuse, “◯”, and when there is no crack, the etch is evaluated as “◎”. did.

  Moreover, about each Example and the comparative example, the water-permeability test by the frame placement method was done, and water-permeability was evaluated by the water-permeation amount measured.

  Here, the water permeability test by the frame placing method was performed as follows.

First, a test piece having a size of 300 × 300 mm in plan view is cut out from the building board and left in the room for a week. Next, a test frame having a rectangular frame shape with a size of 200 × 200 mm is attached to the surface of the test piece with an epoxy resin adhesive, and the weight W ₀ (g) of the test piece to which the test frame is attached is determined. After measuring with an electronic balance, water is poured into the frame on the test piece to a depth of 20 mm. After standing in this state for 24 hours, the water is discarded, the water adhering to the surface of the test piece is wiped off with a waste cloth, and the weight W ₁ (g) of the test piece is immediately measured. Here, the weights W ₀ and W ₁ are measured up to 1/10 g with an electronic balance. And based on the following formula, the water permeation amount A (g / m ² ) is calculated.

A = (W ₁ −W ₀ ) /0.04
At this time, the measured water permeability of 1000 g / m ² is “X”, the water permeability of 500 g / m ² or more and less than 1000 g / m ² is “Δ”, and the water permeability is 100 g / m ² or more and 500 g / m ^2. Those with less than m ² were evaluated as “◯”, and those with a water permeability of less than 100 g / m ² were evaluated as “」 ”.

  The above results are shown in Table 1 below.

It is the schematic which shows an example of the process of inkjet coating.

Explanation of symbols

  1 Inorganic board

Claims (4)

A surface layer having a thickness of 10 to 50 mm is formed by spraying a dry or semi-dried powdery surface material mainly composed of cement on the surface of the wet sheet obtained by molding the cement slurry. The surface on which the layer is formed is pressed at a pressing pressure in the range of 1 to 20 MPa to form a concavo-convex pattern, and the surface layer has a thickness of 0.5 to 5 mm and a density of 0.9 to 1.40 g / cm. ^3. A method for producing a building board, characterized in that after setting to ³ , curing and curing, forming a receiving layer on the surface of the obtained inorganic board, and then applying inkjet coating.   The method for manufacturing a building board according to claim 1, wherein the surface material has a water repellent added thereto.   The method for producing a building board according to claim 2, wherein the water repellent is a silane-based water repellent.   A building board manufactured by the method according to claim 1.

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