JP2006348562A - Plate for building and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent cracking by drying and separation of a waterproof layer and a lightweight cement layer, by reducing a variation in strength in a plate for building. <P>SOLUTION: In this plate 1 for building, the lightweight cement layer 6 is laminated on a base board 2 composed of a fiber board via a surface waterproof layer 3 (and a recess-projection layer 4), and a butt end processing layer is arranged on a butt end surface of the base board by using a synthetic rubber-based or synthetic resin-based butt end processing agent. When manufacturing this plate for building, after forming the surface waterproof layer and the butt end processing layer, the lightweight cement layer is formed, cured and hardened on the surface waterproof layer (or the recess-projection layer). A medium density fiber board MDF manufactured by a dry process is desirably used as the fiber board. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a building board that exhibits excellent fireproof performance by having a lightweight cement layer on the surface, and a method for manufacturing the same.

Examples of this type of conventional building board include, for example, a board, a waterproof layer formed on the board, and a lightweight cement layer provided on the waterproof layer. As is known, a cement-type uneven layer is provided between the waterproof layer and the lightweight cement layer. Plywood is generally used as a substrate for these conventional building boards.
JP 2000-313088 A Japanese Patent Laid-Open No. 2002-1866

  However, building boards that use plywood as a substrate have a problem in that it is becoming difficult to obtain high-quality plywood veneers as the wood resources tend to be exhausted. Good quality veneer has less variation in specific gravity between the veneers and less specific gravity depending on the location of the same veneer. However, since such high quality veneer is becoming difficult to obtain, the variation in specific gravity is large. A plywood manufactured from a single plate must be used.

  Moreover, the water absorption length expansion coefficient of the plywood is greatly different from the expansion coefficient in the direction perpendicular to the expansion coefficient in the direction parallel to the fiber direction of the surface single plate. In particular, building boards used for building exteriors are often placed in various adverse environments such as high dryness and high temperature and humidity. There was a risk that dryness or peeling would occur in the waterproof layer or lightweight cement layer.

  The above-mentioned patent document also describes the use of a fiberboard as a substrate for a building board, but the waterproof layer and the concavo-convex layer are likely to be cracked and peeled off due to bending during handling such as transportation and construction, Furthermore, for reasons such as economic reasons (increased costs), this type of building board using fiberboard as a substrate has not yet been commercialized.

  Therefore, the problem to be solved by the present invention is to provide a drastic solution to the depletion of wood resources, to reduce the variation in strength in the building board, and to dry and peel off the waterproof layer and the lightweight cement layer. Is to prevent.

  In order to achieve the above object, a building board according to the present invention has a surface waterproof layer provided on the surface of a substrate formed of fiberboard, a lightweight cement layer is provided on the surface waterproof layer, and a synthetic rubber. It is characterized in that a lip treatment layer is provided on the lip surface of the substrate using a wood or synthetic resin type lip treatment agent.

  Further, the building board according to the present invention is provided with a surface waterproof layer on the surface of a substrate formed of fiberboard, and a lightweight cement layer is provided on the surface waterproof layer via an uneven layer, and a synthetic rubber system. Alternatively, a lip treatment layer is provided on the lip surface of the substrate using a synthetic resin-based lip treatment agent.

  By using a fiberboard as a substrate for building boards, the above-mentioned problem of resource depletion is alleviated, and there is no difference in the direction of the substrate and the difference in expansion and contraction, making it isotropic. Drying and peeling can be prevented.

  Furthermore, it is preferable that the fiber board used as a board | substrate of a building board is 4-15 mm in thickness. When the thickness of the fiber board is less than 4 mm, the fiber sheet is too thin and the absolute strength as a structural material is insufficient. When the thickness of the fiberboard exceeds 15 mm, the strength as a structural material becomes large, but on the other hand, the lightness is impaired and handling and construction become difficult. In addition, a building board using such a thick fiberboard as a substrate must use a long and thick nail or screw for fixing, resulting in poor nailing or screwing.

  The fiberboard includes a medium density fiber board (MDF) manufactured by a dry process and having a specific gravity of 0.35 or more, and a hard fiber board manufactured by a wet process and having a specific gravity of 0.80 or more, as defined in JIS A5905. HB) or the like is used as a substrate of the building board of the present invention.

  The fiberboard used in the present invention preferably has an average specific gravity of 0.5 to 1.05. When this is less than 0.5, the hardness of the fiberboard itself is insufficient and the strength and rigidity as a structural material are insufficient. If the average specific gravity exceeds 1.05, the fiberboard itself becomes too hard, and the nailing or screwing required as a building board is deteriorated. Becomes strict and the cost increases.

  Further, in the thickness direction of the fiberboard, a center layer and front and back hard layers having higher specific gravity and water impermeability than the center layer are provided, and the front and back hard layers having high specific gravity are fibers. It is exposed on the front and back of the board.

  The specific gravity of the hard layer is not less than 0.7 in order to give water impermeability and increase the surface hardness to improve the scratch resistance, and when the specific gravity is excessively high, the nailing and screwing properties are also deteriorated. To 1.2 or less.

  Further, it is preferable that the fiberboard as the substrate is previously subjected to treatments such as insect proofing, ant proofing, mold prevention, and antiseptic which are generally performed.

  When using the building board of the present invention as an exterior board for forming the outer wall of a building, or as a base material for finishing an exterior by applying a cosmetic coating material such as cement mortar or plaster on the board, fiber Among the plates, it is particularly preferable to use MDF for the substrate. The reason is as follows.

  Condensation water generated inside the wall due to the temperature difference between the outdoor side and indoor side of the building wall, rainwater entering from the outside, sunlight irradiation to the outer wall surface, etc. The moisture content varies greatly, and this variation is repeated over a long period of time. In MDF, an adhesive is added to wood fibers in the manufacturing process, and the contacts between the wood fibers are three-dimensionally fixed with an adhesive, whereas hardboard uses almost no adhesive. The wood fiber is molded in a state where the wood fibers are simply entangled with each other. For this reason, when the moisture content changes over a long period of time, the MDF has a small amount of contraction and expansion and is excellent in maintaining the initial state. In addition, problems such as dry cracking or peeling of the surface waterproof layer and the uneven layer or swelling and warping of the hard board substrate itself are likely to occur. For these reasons, it is preferable to use MDF among the fiberboards as the substrate particularly when used as a building board for outer walls.

  When molding MDF, synthetic resin adhesives such as phenols, urethanes, melamines, urea / melamines and acrylics, and natural adhesives such as tannins are used alone or in any combination. Then, if necessary, a water-resistant sizing agent such as paraffin, wax, rosin, coumarone is added to obtain MDF that satisfies the above-mentioned requirements.

The surface waterproof layer is formed by uniformly applying a mixture of a synthetic resin emulsion and a synthetic rubber latex on the surface of the substrate with an application device such as a roll coater or a flow coater, and drying it by any means. The application amount is, for example, 120 to 300 g / m ² , and the drying condition is, for example, 80 degrees for 5 to 10 minutes.

  As synthetic resin emulsion, acrylic resin and vinyl chloride resin, etc. As synthetic rubber latex, styrene butadiene rubber (SBR), acrylonitrile butadiene rubber (NBR), methyl methacrylate butadiene rubber (MBR), chloroprene rubber (CR), etc. are used. can do.

  Further, bituminous substances such as tar and asphalt, auxiliary agents such as extenders and dispersants such as clay, talc, calcium carbonate, perlite, and metal powder may be added and mixed in the surface waterproof layer. Further, a waterproof layer can be formed on the back surface of the substrate.

  Alternatively, an uneven layer is formed on the substrate via the surface waterproof layer. This uneven layer has a surface waterproof layer on the surface, cement such as Portland cement and white cement, synthetic resin, latex or bituminous material, aggregate such as calcium carbonate and silica sand, methylcellulose, surfactant, antifoam The mixture is formed by applying a mixture of a molding aid such as an agent and water in a layer form with a coating apparatus such as a roll coater and drying by an arbitrary means. The composition of the mixture forming the uneven layer is, for example, 150 parts of cement (parts by weight, the same applies hereinafter), 150 parts of aggregate, 40 parts of latex, 40 parts of emulsion, 0.3 part of methylcellulose, and 1 part of surfactant.

  The synthetic resin, latex or bituminous material in the uneven layer is preferably the same as that used for the surface waterproof layer, so that there is no intermolecular between the material in the surface waterproof layer and the material in the uneven layer. The attractive force works, and the adhesion strength thereof can be increased. In addition, the cement, aggregate, and molding aid in the concavo-convex layer may be the same as those used for forming the lightweight cement layer described later.

  The formation of the unevenness is, for example, an uncured state immediately after application on the surface of the surface waterproofing layer, such as a cutting roll corresponding to the unevenness of the uneven layer to be formed or a mesh roll wound with a net corresponding to the unevenness. It can be formed by rolling on the mixture application surface. The height of the concavo-convex layer is about 2.5 mm at the maximum. In this way, the surface of the concavo-convex layer is formed in an concavo-convex shape, so that not only the bonding strength (peeling strength) with a light cement layer (light weight cement molding plate) described later is increased, but also integrated by a roll press. When manufacturing the building board of the invention, it is possible to suppress the movement of the lightweight cement-molded board trying to escape in the direction opposite to the conveying direction (upstream side of the roll press) of the board (substrate + surface waterproof layer + uneven layer). it can.

  In the building board of the present invention, a lip treatment layer is formed by uniformly applying a lip treatment agent to the lip surface of the substrate with a coating device such as a roll coater or a flow coater and drying the coating material. By forming the end treatment layer, the adhesion between the substrate and the caulking agent at the time of construction increases, and the waterproofness is improved. The throat treatment layer is formed so as to cover all four surfaces of the lip of the substrate, but may also be formed so as to cover the side surfaces of the surface waterproof layer and the uneven layer. Can be further improved. The end treatment layer is formed before the lightweight cement layer is provided on the surface waterproof layer or the uneven layer.

  As the end treatment agent, a synthetic resin type or a synthetic rubber type is used. As the synthetic resin-based wood treating agent, one or an arbitrary mixture of acrylic resin, urethane resin, epoxy resin, ethylene vinyl acetate resin and the like can be used. As a synthetic rubber-based wood treating agent, one or any mixture of synthetic rubber latex such as styrene butadiene rubber (SBR), acrylonitrile butadiene rubber (NBR), methyl methacrylate butadiene rubber (MBR), chloroprene rubber (CR), or the like may be used. Can do.

  The lightweight cement layer is a board in which a waterproof surface layer is provided on the substrate and a throat treatment layer is provided on the top surface of the substrate, or a concavo-convex layer is provided on the top surface of the substrate through the waterproof surface layer, and on the bottom surface of the substrate. It is formed on a plate provided with a wood end treatment layer, and is formed by a lightweight cement mixture mainly composed of cement, synthetic resin foam particles, aggregate, reinforcing fiber, molding aid and kneading water. The specific gravity after curing of the lightweight cement layer is 0.2 to 1.2, preferably 0.6 to 0.7.

  As the cement, it is possible to use any cement such as ordinary Portland cement, Portland cement such as early-strength Portland cement, natural cement, alumina cement, super-hard cement. In order to suppress shrinkage during hardening of the cement and prevent warping of the building board, the amount of cement is preferably 35% by weight or less of the total weight of the lightweight cement mixture excluding water. Further, unless the blending amount of cement is 20% by weight or more of the total weight, the curing becomes insufficient and the required strength cannot be obtained.

  Synthetic resin foam particles include styrene resins such as polystyrene, olefin resins such as polyethylene and polypropylene, copolymers such as acrylonitrile / styrene copolymer, styrene / ethylene copolymer, polyvinyl chloride, and polyvinylidene chloride. A synthetic resin such as a vinyl chloride resin can be foamed to form spherical or substantially spherical beads, or those obtained by pulverizing these synthetic resin foam particles. Among these, polystyrene foam particles are a preferred choice because of their high strength and low cost. The synthetic resin foam particles preferably have an average particle size of 0.1 to 10.0 mm, an average specific gravity of 0.03 to 0.2, and an expansion ratio of 10 to 60 times. It is preferable to mix 6 to 21% by weight with respect to the weight. Instead of synthetic resin foam particles, inorganic lightweight aggregates such as pearlite may be mixed.

  As the aggregate, quartzite powder, fly ash, slag, regenerated powder or the like can be used, and 75 to 250% by weight is mixed with the cement weight. Thus, by increasing the blending ratio of the aggregate in the lightweight cement layer, it is possible to reduce warping by reducing shrinkage when the lightweight cement layer is cured.

  As the reinforcing fiber, inorganic fibers such as wollastonite, sepiolite, ceramic fiber and glass fiber, and organic fibers such as pulp and polypropylene fiber can be used alone or in combination. By mixing reinforcing fibers in the lightweight cement layer, the strength can be increased through the bonding force between the fibers, but on the other hand, if the amount of reinforcing fibers mixed is too large, the shrinkage force when hardening the cement is excessive. Therefore, it is preferable that 0.2 to 9% by weight of the reinforcing fiber is mixed with respect to the cement weight because warpage is likely to occur when manufactured as a building board.

  As a molding aid, cellulose derivatives such as methyl cellulose (MC), ethyl cellulose (EC), carboxymethyl cellulose (CMC) can be used, and 0% with respect to the total weight of cement, synthetic resin foam, aggregate and reinforcing fibers. Add 1-10% by weight.

  In addition, it is possible to improve the binding strength of cement by mixing a synthetic resin or latex in the lightweight cement mixture with an addition amount of 20% or less in terms of solid content.

  Further, kneading water is added to the above material and kneaded sufficiently to obtain a light cement mixture. The amount of kneading water is preferably 60 to 210% by weight with respect to the cement weight.

  The light-weight cement mixture is provided with a surface waterproof layer on the substrate and a front end of the substrate provided with a front end treatment layer, or an uneven layer is provided on the substrate via the front surface waterproof layer and the front end of the substrate. The building board of the present invention is manufactured by applying and curing on the surface of the board provided with the end treatment layer. More specifically, the obtained lightweight cement mixture is applied to the surface of the plate using a roll coater, continuous lysing gun, knife coater or the like so that the thickness after curing is about 2 to 20 mm. You may perform a drying process by arbitrary means after application | coating. The drying process is performed, for example, with hot air at 60 to 80 degrees for 10 to 30 minutes.

  Alternatively, the obtained lightweight cement mixture is put into an extrusion molding machine to obtain a lightweight cement molding plate having substantially the same plane dimensions as the plate, and immediately thereafter, the molding plate is placed on the plate. The building board of the present invention can be produced by forming a lightweight cement layer by pressurizing the surface with a roll press or the like and heating and drying and curing with a dryer.

  In any of the above cases, dozens of plates coated with a lightweight cement mixture are cured at room temperature or heat-cured by a deposition method such as flat stacking or deposition on a curing shelf. In the case of flat stacking, it may be deposited as it is, but if it is deposited with a synthetic resin film / sheet interposed between the plates to which the lightweight cement mixture is applied, the fiberboard substrate with the moisture of the lightweight cement mixture This is a preferable method because it can prevent moisture from being absorbed from the back surface side, and can prevent the back surface of the fiberboard substrate from being discolored or denatured by the elution alkali content from the lightweight cement mixture. After curing, the curing is cured for 3 days and then cured for another week.

  In addition, when forming a chamfer in the board for building manufactured in this way or cutting it to an exact size, cutting and grinding are performed after the lightweight cement layer is cured after curing.

  The building board of the present invention is mass-produced in advance in a factory, and when this is used as a base plate for exterior, it is fixed to a structural material such as a pillar or a stud by nailing, etc. A caulking agent is filled in the butt portion (joint portion) without gaps, and a net-like material is fixed so as to completely surround the caulking agent, and then mortar is applied to the entire surface to form a mortar layer. The mortar is, for example, a cement mortar obtained by kneading cement, sand, latex, and water. The thickness of the cement mortar is applied so as to be in the range of about 4 mm to 15 mm depending on the fireproof performance required for the wall structure of the outer wall.

  As the caulking agent, an acrylic resin, urethane resin, silicon, modified silicon, polysulfite, or the like can be used as a main component.

  When the abutting portion between the building boards is formed in a state where the chamfered surfaces that have been chamfered are in close contact with each other, the caulking agent can be filled in the V-groove portion formed between the chamfered portions. However, in the case of joints where chamfering cannot be performed between adjacent construction plates, between the construction plates and the sash, etc. There is a case. In such a case, since the caulking agent is filled (placed) in the interval portion in the abutting portion, the waterproofness is influenced by the adhesion between the mouth portion of the building board and the caulking agent. However, the wooden plank surface of the building board may have foreign matter such as chips and dust attached to it, resulting in poor adhesion to the caulking agent. As a result, even if it is filled with the caulking agent, it is sufficiently waterproof. It may not be obtained. In addition, water repellent components may be included in the adhesive and water-resistant sizing agent added in the manufacturing process of the fiberboard used as the substrate, and when using an aqueous caulking agent, the adhesiveness decreases, Similarly, sufficient waterproofness cannot be ensured. However, in the present invention, since the kerf treatment layer is formed on the kerf surface of the building board, is it possible to form a smooth kerf treatment layer in the form of coating even if impurities are attached to the kerf part? Or, it is possible to drop and remove impurities when applying the lip treatment agent, and the lip surface containing water repellent components is also coated with the lip treatment layer, so the adhesion with the caulking agent is good. Thus, the waterproof property can be improved.

  Note that a chamfered portion that is chamfered at an angle of 30 to 60 degrees with respect to the surface may be formed in the mouth of the substrate. When the chamfered portion is formed, it is preferable that the end treatment layer is formed from the end surface to the chamfered portion, and the uneven layer is provided on the upper side of the chamfered portion.

  The net-like material is fixed so as to cover the caulking agent in the joint portion, reinforces the mortar to be applied later, and prevents cracking. The net-like material is arbitrarily selected from organic fibers or inorganic fibers such as polyamide fibers, acrylic fibers, polyethylene fibers, polypropylene fibers, polyvinyl alcohol fibers, cotton fibers, alkali-resistant glass fibers, and carbon fibers. A net obtained by weaving one or more kinds of fibers can be used. Particularly, an acrylic fiber net, an alkali glass fiber net, a cotton fiber net, a polyvinyl alcohol fiber net, and the like are preferably used.

  The mortar is, for example, a cement mortar obtained by kneading cement, sand, latex, and water. The thickness of the cement mortar is applied so as to be in the range of about 7 mm to 20 mm according to the fireproof performance required for the wall structure of the outer wall.

Although the mortar layer shrinks by drying with time, its dimensional change rate (dry shrinkage strain) is about (0.4 to 0.8) × 10 ⁻³ . Therefore, the dimensional change when the length of the building base material is 1820 mm is 0.7 to 1.5 mm, which is almost negligible. In the present invention, not only the surface of the substrate but also the mouth end is provided with a water end treatment layer that exhibits a waterproof function, so that the change in the moisture content of the substrate with respect to the humidity change in the surrounding environment is so small that it can be ignored. Since the shrinkage and expansion between the two are substantially equal, it is possible to prevent warping of the building base material itself, dry cracking and peeling of the mortar layer, and the like.

  By using a fiberboard as a substrate for a building board, the problem of resource depletion can be alleviated.

  Moreover, since the specific gravity of the vicinity of the front and back surfaces (front and back hard layers) that are in direct contact with the hot platen in the manufacturing process of the fiberboard increases, the change in moisture content of the fiberboard placed in the natural environment is relatively small. Smaller than plywood. Moreover, since the fiber board is isotropic in the direction of expansion and contraction, the expansion and contraction force to the surface waterproof layer is transmitted isotropically. Accordingly, the strain applied to the surface waterproof layer and the lightweight cement layer is relatively small, and it is possible to suppress the occurrence of dry cracking and peeling in the surface waterproof layer and the lightweight cement layer.

  In addition, the use of fiberboard as a substrate reduces variations in specific gravity between multiple building boards and local specific gravity within the same building board. Can be provided.

  Furthermore, in the present invention, not only the surface waterproof layer is provided on the surface of the fiberboard which is the substrate, but also the lip treatment layer covering the lip face is provided, so that moisture absorption from the lip face is effectively suppressed. The dimensional change rate in the natural environment is reduced and becomes almost the same as the dimensional change rate of the mortar layer coated and formed on it. Separation can be prevented. Further, the water repellency on the surface of the substrate mouth can be suppressed, the adhesion between the surface of the substrate mouth and the caulking agent can be improved, and the waterproof property can be improved.

  Furthermore, by using a fiberboard with a thickness of 4 to 15 mm for the substrate, while maintaining the absolute strength as a structural material, the lightweight property, the handling property, the nailing property, and the screwing property are well maintained, Manufacturing cost can be reduced.

  Furthermore, even if the moisture content changes over a long period of time by using MDF as a substrate among fiberboards, the surface waterproof layer and lightweight cement layer provided on the surface are dried or peeled off or hardboard It does not cause problems such as swelling of the substrate itself, and is particularly suitable for use as an exterior plate or exterior base plate for forming an outer wall.

  Further, in the method for manufacturing a building board, the substrate is absorbed by moisture released from the lightweight mortar layer during production or curing by forming the surface waterproof layer and the lip treatment layer before forming the lightweight mortar layer. It is possible to prevent this, and to prevent a dimensional change of the substrate due to moisture absorption.

  A building board 1 according to an embodiment of the present invention shown in FIG. 1 has an MDF as a substrate 2, a lightweight cement layer 6 is formed on the surface thereof via a surface waterproof layer 3, and the quadruple lip of the MDF substrate 2. A throat treatment layer 4 is formed at the end. The MDF used for the substrate 2 has a thickness of 9 mm and an average specific gravity of 0.8. A chamfered portion 7 is formed on the front side of the quadruple front end of the MDF substrate 2, and the end treatment layer 4 is formed so as to cover not only the front end of the MDF substrate 2 but also the chamfered portion 7. ing.

  A building board 1 ′ according to another embodiment of the present invention shown in FIG. 2 uses an MDF as a substrate 2, and a lightweight cement layer 6 is formed on the surface thereof via a surface waterproof layer 3. A front end treatment layer 4 is formed on the front end of the end, and a rear waterproof layer 8 is formed on the rear surface of the MDF substrate 2. The MDF used for the substrate 2 has a thickness of 9 mm and an average specific gravity of 0.8. A chamfered portion 7 is formed on the front side of the quadruple front end of the MDF substrate 2, and the end treatment layer 4 is formed so as to cover not only the front end of the MDF substrate 2 but also the chamfered portion 7. ing.

  A building board 1 '' according to an embodiment of the present invention shown in FIG. 3 has an MDF as a substrate 2, and a surface waterproof layer 3, an uneven layer 5 and a lightweight cement layer 6 are sequentially laminated on the surface, A throat treatment layer 4 is formed on the quadruple lip face of the MDF substrate 2. The MDF used for the substrate 2 has a thickness of 9 mm and an average specific gravity of 0.8. The chamfered portion 7 is formed on the front side of the quadruple front end of the MDF substrate 2, and the front end treatment layer 4 is formed so as to cover not only the front end of the MDF substrate 2 but also the chamfered portion 7. ing. The height h of the concavo-convex layer 6 is about 2 mm and has an irregular concavo-convex pattern.

  The building board 1 ′ ″ according to an embodiment of the present invention shown in FIG. 4 has an MDF as a substrate 2 and a surface waterproof layer 3, an uneven layer 5 and a lightweight cement layer 6 are sequentially laminated on the surface. The MDF substrate 2 is provided with a throat treatment layer 4 on the four-sided lip surface of the MDF substrate 2, and a back surface waterproof layer 8 is formed on the back surface of the MDF substrate 2. The MDF used for the substrate 2 has a thickness of 9 mm and an average specific gravity of 0.8. The chamfered portion 7 is formed on the front side of the quadruple front end of the MDF substrate 2, and the front end treatment layer 4 is formed so as to cover not only the front end of the MDF substrate 2 but also the chamfered portion 7. ing. The height h of the concavo-convex layer 6 is about 2 mm and has an irregular concavo-convex pattern.

  FIG. 5 shows a mortar outer wall structure in which the building board 1 ″ in FIG. 3 is mass-produced at a factory and used as an exterior base material. That is, after this building board 1 ″ is abutted and fixed on the pillar 9 with a nail 10 and fixed with a nail 10, an acrylic caulking agent 11 is filled in the spaced joints without gaps. After the net-like object 12 is fixed so as to completely surround the caulking agent 11, mortar is applied to the entire surface to form a mortar layer 13, thereby forming an outer wall.

  1 except that the test piece of the building board 1 of FIG. 1 and the surface waterproof layer 3 are formed, but the throat treatment layer 5 is not formed, and the quadruple lip face of the MDF substrate 2 is exposed as it is. A comparative example of the test body having the same structure as the above was subjected to a water absorption test and a caulking joint tensile test. All the test bodies were 50 mm long × 50 mm wide × 9 mm thick.

  Kiguchi water absorption test is to measure the change in weight of the test specimen when water is absorbed only from the specimen's mouthpiece surface. Cover and put into a container with water depth of 20mm with the end facing down, weight change before test and after 24 hours (1 day), 72 hours (3 days) and 168 hours (1 week) The rate (water absorption rate) was compared.

  As a result, the specimens of the examples of the present invention showed a slight increase in weight of 1.4% after 24 hours, 3.3% after 72 hours and 7.3% after 168 hours. Although it was only shown, the weight increase of the test body of the comparative example was as large as 2.0%, 4.4%, and 8.9%, respectively. From this, it was proved that the water absorption rate can be sufficiently suppressed by forming the end treatment layer 5 on the quadrant end face of the MDF substrate 2.

  For this reason, even when the outer wall was constructed as shown in FIG. 5, the mortar layer 13 was not cracked or peeled off, and the handling property during transportation and construction was good.

  The caulking joint tensile test was performed on the base with a space of 5 mm between the specimens, the caulking agent was filled in the gap, and cured for 3 days, and then the tensile strength of the caulking joint was measured.

  As a result, the tensile strength of the test body of the embodiment of the present invention is 21.7 kg, whereas the tensile strength of the test body of the comparative example is 10.0 kg, and the test body of the embodiment of the present invention is the comparative test body. It was proved that the adhesion strength was remarkably increased, showing a value more than twice as large as.

It is sectional drawing which shows the board for construction by one Embodiment of this invention. It is sectional drawing which shows the board for building by another embodiment of this invention. It is sectional drawing which shows the board for building by another embodiment of this invention. It is sectional drawing which shows the board for building by another embodiment of this invention. It is sectional drawing which shows the mortar outer wall structure which used the board for building of FIG. 3 as a base material for exterior.

Explanation of symbols

1, 1 ', 1'',1''' Building board 2 Fibreboard (MDF) as substrate
DESCRIPTION OF SYMBOLS 3 Surface waterproofing layer 4 Knot processing layer 5 Concavity and convexity layer 6 Light weight cement layer 7 Chamfering part 8 Back surface waterproofing layer 9 Pillar 10 Nail 11 Caulking agent 12 Net-like material 13 Mortar layer

Claims (6)

A surface waterproof layer is provided on the surface of the substrate formed of fiberboard, and a lightweight cement layer is provided on the surface waterproof layer, and the front end of the substrate using a synthetic rubber-based or synthetic resin-based end treatment agent A board for construction, characterized in that it is provided with a throat treatment layer. A surface waterproof layer is provided on the surface of the substrate formed of fiberboard, and a lightweight cement layer is provided on the surface waterproof layer via an uneven layer, and a synthetic rubber-based or synthetic resin-based wood treating agent is used. An architectural board, characterized in that a lip treatment layer is provided on the lip face of the substrate. Synthetic resin treatment agent and / or styrene butadiene rubber (SBR), acrylonitrile butadiene rubber (NBR), methyl, whose end treatment layer is made of any one or any mixture of acrylic resin, urethane resin, epoxy resin, ethylene vinyl acetate resin The building board according to claim 1 or 2, wherein the building board is formed of a synthetic rubber-based treatment agent comprising any one of methacrylate butadiene rubber (MBR) and chloroprene rubber (CR) or an arbitrary mixture thereof. 4. The building board according to claim 1, wherein the fiber board is a medium density fiber board (MDF) manufactured by a dry process. After forming a surface waterproof layer on the surface of the substrate made of fiberboard and forming a lip treatment layer on the surface of the substrate using a synthetic rubber or synthetic resin lip treatment agent, lightweight cement on the surface waterproof layer A method for producing a building board, comprising forming a layer and curing and curing the lightweight cement layer. A surface waterproof layer and a concavo-convex layer with irregularities formed on the surface thereof are sequentially formed on the surface of the substrate made of fiberboard, and a synthetic rubber-based or synthetic resin-based lip treatment agent is used on the lip surface of the substrate. After forming, a lightweight cement layer is formed on the uneven layer, and the lightweight cement layer is cured and cured.

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