JP2006348555A - Plate for building - 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: This plate 1 for building is formed by successively laminating the lightweight cement layer 5 on a base board 2 via the waterproof layer 3, or the plate 1' for building is formed by successively laminating a recess-projection layer 4 forming a recess-projection on a surface and the lightweight cement layer 5 on a base board 7 via the waterproof layer 3. A fiber board having a coefficient of water absorption of 18% or less is used as the base board. 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 its surface.

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, the present invention according to claim 1 is directed to a board for construction in which a lightweight cement layer is laminated on a substrate via a waterproof layer, and a fiber board having a water absorption of 18% or less is used as the substrate. It is used for.

  The present invention according to claim 2 is a building board in which a concavo-convex layer having a concavo-convex surface and a lightweight cement layer are sequentially laminated on a substrate via a waterproof layer, and the water absorption is 18% or less. It is characterized by using a fiberboard as a substrate.

  The use of fiberboard as a board for building boards alleviates the above-mentioned resource depletion problem and eliminates differences in board orientation and expansion and contraction, making it isotropic, and drying of waterproof and lightweight cement layers. Cracking and peeling can be prevented.

  In addition, by using a fiberboard with a water absorption rate of 18% or less for the substrate, the moisture content of the substrate changes even if condensation, rainwater intrusion, or humidity changes occur in the wall where the building base material is constructed. It is effective that the waterproof layer formed on the surface and the uneven layer are less prone to dry cracks and peeling, and that the mortar layer coated and formed on the uneven layer surface is also effective. Can be prevented.

  In addition, the water absorption rate test method shall be based on the water absorption rate test of the fiber board prescribed | regulated to JISA5905. That is, a test piece in an air-dried state is placed vertically in a place at a depth of about 2 cm from the water surface in 20 ° C. water, taken out after being immersed for 24 hours, and the mass change of the test piece before and after immersion is compared, The ratio of the increased mass to the test piece before immersion is calculated to obtain the water absorption rate.

  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. A material satisfying the requirements of the water absorption range is selected from HB) and the like and used as a board for 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. Moreover, the thing whose specific gravity difference of a center layer and front and back hard layers is 0.1-0.5 can be used. Preferably, those having a specific gravity difference of 0.2 to 0.5 are used. By setting the difference in specific gravity within this range, it is possible to obtain a substrate that is lightweight and has an excellent bending Young's modulus. If the specific gravity difference is smaller than 0.1, sufficient bending strength cannot be achieved unless the thickness ratio of the front and back hard layers is increased, resulting in an increase in weight, while the specific gravity difference is larger than 0.5. Delamination tends to occur between the center layer and the front and back hard layers.

  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 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.

  A chamfered portion that is chamfered at an angle of 30 to 60 degrees with respect to the surface can be formed at the mouth of the substrate. When the chamfered portion is formed, the waterproof layer is formed over the chamfered portion, and when the concavo-convex layer is formed, the concavo-convex layer is also provided on the upper side of the chamfered portion.

The waterproof layer is formed by uniformly applying a mixture of the synthetic resin emulsion and the synthetic rubber latex to the surface of the substrate with an application device such as a roll coater or a flow coater and drying the mixture by an arbitrary 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.

  In addition, 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 to the waterproof layer. The waterproof layer is formed on at least the front surface of the substrate, and the waterproof layer can also be formed on the end and / or the back surface.

  As a result, a plate having a waterproof layer formed on the substrate is obtained.

  Alternatively, the plate can be obtained by forming an uneven layer on the substrate via the waterproof layer. This rugged layer has a waterproof layer surface with cement such as Portland cement and white cement, synthetic resin, latex or bituminous material, aggregates such as calcium carbonate and silica sand, methylcellulose, surfactant and antifoaming agent. The mixture is formed by applying a mixture of a molding aid such as the above 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 concavo-convex layer is preferably the same type as that used in the waterproof layer, so that intermolecular attractive force is generated between the material in the waterproof layer and the material in the concavo-convex layer. Can increase their adhesion strength. 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, a mixture in an uncured state immediately after application of a meshing roll corresponding to the unevenness of the uneven layer to be formed or a net winding roll wound with a net corresponding to the unevenness on the surface of the waterproof layer. It can be formed by rolling on the coated 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, the lightweight cement-molded board can suppress movement to escape in the direction opposite to the conveying direction of the board (substrate + waterproof layer + uneven layer) (upstream from the roll press). .

  The lightweight cement layer is provided on a board in which a waterproof layer is formed on a substrate, or on a board in which an uneven layer is formed on the substrate via a waterproof layer, cement, synthetic resin foam particles, aggregate, It is formed from a lightweight cement mixture mainly composed of reinforcing fibers, molding aids 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 lightweight cement mixture is applied to the surface of a board on which a waterproof layer is formed on a substrate, or a board on which a concavo-convex layer is formed on a substrate via a waterproof layer, and is cured, whereby the architecture of the present invention is applied. A board is manufactured. 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 at a factory, and can be used directly as an exterior board after being fixed to a structural material such as a pillar or a stud by nailing or the like when constructing an outer wall. If necessary, paint the surface to finish the outer wall.

  When the building board of the present invention is used as a base plate for exteriors, it is fixed to a structural material such as a pillar or a stud by nailing or the like, and then a mortar is applied to the surface to form a mortar layer. To do. 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.

  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. Further, since the fiberboard has an isotropic direction of expansion and contraction, the expansion and contraction force to the waterproof layer is transmitted isotropically. Accordingly, the strain applied to the waterproof layer and the lightweight cement layer is relatively small, and it is possible to suppress the occurrence of dry cracks and peeling in the 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, by using a fiberboard having a water absorption of 18% or less for the substrate, there is no difference in expansion and contraction due to the difference in the direction of the substrate, and in addition to being uniform in the length direction and the width direction, this building base material Even if water condensation and humidity changes occur due to condensation, rain water intrusion, etc., the moisture content change of the substrate is suppressed to a small range, and the waterproof layer formed on the surface, the uneven layer It becomes difficult for peeling to occur, and furthermore, it is possible to prevent dry cracking and peeling from occurring on the mortar layer applied to these surfaces.

  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 has changed over a long period of time by using MDF as a substrate among fiberboards, a dry layer or peeling of a waterproof layer or lightweight cement layer provided on the surface or a hardboard substrate It does not cause problems such as swelling of itself, and is particularly suitable for use as an exterior plate or exterior base plate for forming an outer wall.

  A building board 1 according to an embodiment of the present invention shown in FIG. 1 is formed by using MDF as a substrate 2, a waterproof layer 3 formed on the surface, and a lightweight cement layer 6 formed on the waterproof layer 3. The MDF used for the substrate 2 has a thickness of 9 mm, an average specific gravity of 0.8, and a water absorption of 11%.

  This building board 1 is mass-produced at the factory, and after nailing and fixing to structural materials such as columns and studs, cement mortar is applied on it, the handling at the time of transportation and construction is good, Even over a long period of time, the waterproof layer 3, the lightweight cement layer 6, and the cement mortar did not crack or peel.

  A building board 1 ′ according to another embodiment of the present invention shown in FIG. 2 has an MDF as a substrate 2, a concavo-convex layer 4 is formed on the surface via a waterproof layer 3, and a lightweight cement is further formed on the concavo-convex layer 4. Layer 6 is formed. The MDF used for the substrate 2 has a thickness of 9 mm, an average specific gravity of 0.8, and a water absorption of 11%. The height h of the concavo-convex layer 4 is about 2 mm and has an irregular concavo-convex pattern.

  This building board 1 'is mass-produced at the factory, and is nailed and fixed to a structural material such as a pillar or a stud. As a result, it is easy to transport and construct. Even in this case, the waterproof layer 3, the uneven layer 4, and the lightweight cement layer 6 were not cracked or peeled off. In addition, this building board 1 'was used as a base plate for exterior, and after nailing and fixing to a structural material such as a column or a stud, cement mortar was applied on it, and cracked into cement mortar even for a long time. It was possible to finish the outer wall with the required fire-proof performance and excellent design properties.

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 other embodiment of this invention.

Explanation of symbols

1, 1 'Building board 2 Fibreboard (MDF) as substrate
3 Waterproofing layer 4 Concavity and convexity layers 5, 5 'Base plate 6 Lightweight cement layer

Claims (3)

A building board, wherein a lightweight cement layer is sequentially laminated on a substrate through a waterproof layer, and a fiber board having a water absorption of 18% or less is used for the board. In a building board in which a rugged layer having a rugged surface and a lightweight cement layer are sequentially laminated on a substrate via a waterproof layer, a fiber board having a water absorption of 18% or less is used for the substrate. Architectural board characterized by 4. The building board according to claim 1, wherein the fiber board is a medium density fiber board (MDF) manufactured by a dry process.

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