JPH0242958B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a mineral fiberboard used as a ceiling material, wall material, or other various panel materials for buildings. [Conventional structure and problems] Conventionally, in order to provide rock wool boards used for ceiling panels, etc. with sound absorption and heat insulation properties, when making fiberboard, the slurry concentration was lowered and long fiber materials were used. It is possible to lower the density by loosening the intertwining of the fibers by adding fibers or dispersants, or by dispersing lightweight aggregates in the slurry to make some of the mineral fibers Efforts have been made to reduce weight by replacing it with aggregate, but there is a limit to weight reduction with conventional single-layer mineral fiberboard due to strength and surface cosmetics, with a specific gravity of 0.4 or less. If you use a board with a low specific gravity, it may be able to maintain its shape as a board, but it may lack strength as a ceiling board or wall board.
Another problem is that since the fibers are hard inorganic fibers, the surface becomes extremely uneven, impairing the surface smoothness, and even when smoothed by sanding or the like, the surface is sparse, resulting in poor cosmetic properties. In addition, if the density of the fibers is reduced to reduce weight, many voids will appear on the surface, and when finishing with paint, the paint will be sucked into the voids in the surface layer. Undercoating is required. Moreover, in order to form a good coating film, it is necessary to apply a large amount of paint in consideration of the amount of paint sucked in, and there is a risk that the fire retardant properties will be lowered. Furthermore, if a large amount of paint is sucked in, the surface layer expands and stretches, causing warping. Also, when applying a decorative sheet instead of painting, lightweight fiberboard with a sparse fiber density has mineral fiber fuzz on its surface, so the fluffy mineral fibers can easily break. There is a problem that the adhesiveness of the decorative sheet is extremely poor. [Object of the invention] The present invention has been made in view of the above problems, and
By forming a skin layer with excellent peelability,
To improve the strength and surface properties of a porous mineral fiberboard with a low fiber density, to improve paintability and cosmetic properties, and to expand the range of lightweight mineral fiberboards that can be used as ceiling boards and wall boards. The present invention provides a mineral fiberboard that can be used in a variety of ways. [Structure of the Invention] In order to achieve the above object, the mineral fiberboard of the present invention has a mineral fiberboard having a specific gravity of 0.2 to 0.4 made from mineral fibers such as rock wool. It is made by integrally layering a dense skin layer containing ~2000μ mineral short fibers and a binder at a ratio of 2 to 20%, and the surface is smooth and fluff-free even though the substrate is lightweight. , and is hardened and has a high specific strength. [Description of Embodiments] Embodiments of the present invention will be explained with reference to the drawings. 1
is a mineral fiber with a specific gravity of 0.2 to 0.4 that is made from rock wool or slag wool and is made by adjusting the slurry concentration, adding lightweight aggregate, long fibers, dispersing agents, foaming agents, etc. It is mainly made of a plate, and a dense skin layer 2 mainly composed of short mineral fibers is integrally layered on its surface. The skin layer 2 is formed by blending a binder at a ratio of 2 to 20% mainly with mineral short fibers, and the fiber length is 100 to 2000μ, preferably 100μ.
It is formed mainly from pulverized short mineral fibers so that more than 50% of the fibers have a fiber length of ~1000μ. Here, the reason for using a length of 100 to 2000μ is that if only the surface smoothness is to be improved, the length is shorter than the length of 10 to 30mm used for ordinary mineral fiberboard manufacturing. However, unlike organic fibers such as vegetable fibers, mineral fibers lack flexibility, so mineral fibers are formed by making slurries prepared separately. Even if the fiber layers are stacked together, there is almost no intertwining of the fibers between the layers, and a new problem arises in that the bond strength is weak and the fibers easily peel off. If so, the fiber length is extremely short and the short fibers are located in the overlapped portion, and the short fibers easily flow due to pressure or the movement of water during dehydration, and bite into the voids of the mineral fibers that constitute the mineral fiber main body 1 in the lower layer. This is because when they come into close contact with each other, the bonding points between the two significantly increase, and by applying a binder to the bonding points, the bonding points are firmly fixed and peeling of the skin layer is prevented. In addition, since the skin layer is formed mainly of short fibers, it has heat insulation, sound absorption, and air permeability, and is also formed into a sheet of uniform thickness using a paper-making device separate from the mineral fiber main body 1. It can be formed and layered, and the thickness and density can be easily adjusted. To obtain such a mineral fiberboard, first, as shown in Figure 2, a low-density fiberboard is prepared by adding an appropriate amount of a binder such as starch to mineral fibers such as rock wool or slag wool with a fiber length of 4 to 30 mm. If necessary, inorganic lightweight aggregates such as perlite and shirasu foam, dispersants, foaming agents, or long fiber materials are added to the mixed slurry, and paper is made using a fourdrinier or round net machine to produce mineral fibers. A porous wet mat 11 having a specific gravity of 0.2 to 0.4 after drying is formed as the main body 1. Mineral fiberboard with a specific gravity within this range is mainly produced by mixing lightweight aggregate in an appropriate ratio and then making the fibers by adjusting conditions such as the stirring state of the fiber slurry and the papermaking speed during papermaking. This can also be achieved by papermaking with a large number of voids, and it is not necessarily necessary to form the paper by mixing lightweight aggregate. On the other hand, the skin layer 2 is made by crushing mineral fibers such as rock wool and slag wool to a fiber length of 100~
2000μ, preferably 100 to 1000μ short fibers, and starch or 2 to 20% of these mineral short fibers are added.
In addition to adding binders such as PVA, phenol, acrylic, acrylic styrene, petroleum resin, etc., if necessary, short organic fibers such as waste paper pulp, coloring agents such as pigments, or calcium carbonate,
Inorganic powders such as clay, silica, magnesium carbonate, mineral powder, mica powder, metal powder, aluminum hydroxide, alumina powder, carbon black, and white carbon are added as appropriate to form a slurry mainly consisting of mineral short fibers. This slurry is made into a wet sheet 12 that is thinner than the wet mat 11 by using another paper making device, and is overlapped with the wet mat 11 of the mineral fibers.
After dehydration under pressure (step 4) or suction dehydration (5) as shown in FIG. 3, it is dried and integrated with the mineral fiberboard main body 1. The skin layer can also be provided by supplying a layer of a highly concentrated slurry containing short mineral fibers and a binder to the upper surface of a wet mat, followed by dehydration and drying. In the above manufacturing method, a binder 6 such as a starch solution, phenol resin, or melamine resin is applied to the interface between the mineral fiberboard main body 1 and the skin layer 2 mainly composed of mineral short fibers to improve the adhesion between the two. It may be formed by increasing the The skin layer 2 may be arranged on both sides of the mineral fiberboard main body 1 and layered integrally. In this case, both sides of the mineral fiberboard are formed into a dense and hard surface layer to form a dense and hard surface layer. It is possible to improve the strength, and it is possible to obtain a mineral fiberboard that is smooth on both sides and has a high specific strength. Furthermore, a known pattern such as a travertine pattern or a pin hole pattern may be formed on the surface of the skin layer 2. In this case, since the skin layer is dense, the hole pattern becomes sharp and cosmetic. It will be excellent. Next, a comparison of the physical properties of the mineral fiberboard of the present invention and the conventional mineral fiberboard with a single layer structure is shown in the table. Comparative example A slurry of 79 parts by weight of mineral fibers (fiber length 4 to 30 mm), 10 parts by weight of waste paper pulp, 6 parts by weight of inorganic foam, and 4 parts by weight of starch was made into a paper with a thickness of 12 mm and a specific gravity.
A mineral fiberboard with a low specific gravity of 0.32 was formed. Although this material was relatively lightweight, the surface was rough and the surface smoothness was poor. 1st Example A low-density wet mat of mineral fibers is made using a slurry made by mixing and stirring 95 parts by weight of mineral fibers (fiber length 4 to 30 mm) and 5 parts by weight of starch, and crushed mineral fibers are coated on the surface of the wet mat. Short fiber (fiber length 100~
Thin wet sheets made from a slurry with a composition of 86 parts by weight of 2000μ), 4 parts by weight of starch, and 10 parts by weight of phenolic resin are layered, dehydrated and dried, and a skin layer of about 0.8 mm thick is layered together to form a whole. A mineral fiberboard with a thickness of 12 mm and a specific gravity of 0.28 was formed. At this time, the specific gravity of the mineral fiberboard main body was 0.21, and the specific gravity of the surface skin layer was 1.25. This material is made of fiberboard, which is the substrate, with extremely low fiber density, and although there are many voids between the fibers, the surface is smooth and dense. It was covered with a skin layer and had excellent surface smoothness. Second Example A wet mat of mineral fibers was made using a slurry of 55 parts by weight of mineral fibers (fiber length 4 to 30 mm), 10 parts by weight of waste paper pulp, 30 parts by weight of inorganic foam, and 4 parts by weight of starch. A thin wet sheet made of a slurry consisting of 80 parts by weight of crushed short mineral fibers (fiber length 200 to 1000μ), 6 parts by weight of waste paper pulp, 4 parts by weight of starch, and 10 parts by weight of phenolic resin is layered on the surface. After dehydration and drying, a skin layer with a thickness of about 0.6 mm was integrally deposited to form a mineral fiberboard with a total thickness of 12 mm and a specific gravity of 0.26.
The specific gravity of the mineral fiberboard main body was 0.21, and the specific gravity of the surface skin layer was 1.2. This product had a smooth surface, did not break during handling, and was satisfactory in terms of strength, even though a large amount of inorganic foam was mixed into the fiberboard substrate. When the physical properties of the three materials were compared, the results shown in the following table were obtained.

〔Effect of the invention〕

As described above, according to the mineral fiberboard of the present invention,
A dense skin layer made of short mineral fibers with a fiber length of 100 to 2000μ mixed with a binder is integrally layered on the surface of a mineral fiberboard with a specific gravity of 0.2 to 0.4 that is produced by wet papermaking. Although the substrate is low-density and lightweight, the surface is smooth and dense, eliminating the need for surface conditioning treatments such as sanding. There is almost no suction, and a uniform coating film can be formed with a small amount of application.It is possible to mix more lightweight aggregate than before with the mineral fiberboard substrate, or to loosen the entanglement of fibers. In order to make the material even more porous, we have expanded the scope of weight reduction and used low-density fiberboard with a specific gravity of 0.4 or less, which was previously difficult to achieve due to strength and cosmetic issues, such as ceiling panels and wall panels. The result is a mineral fiberboard that satisfies the surface properties as described above. Furthermore, since the surface is smooth, the decorative sheet can be attached easily and reliably. Furthermore, since the skin layer is formed by blending a binder with short mineral fibers with a fiber length of 100 to 2000 μm, delamination between the main body of the mineral fiberboard and the skin layer on the surface is less likely to occur, and it is lightweight as well. Regardless, a mineral fiberboard with excellent bending strength and surface strength can be formed.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; FIG. 1 is a sectional view thereof, FIG. 2 is a simplified side view showing the manufacturing method, and FIG. 3 is a simplified side view when suction dehydration is performed. 1... Mineral fiberboard main body, 2... Skin layer.

Claims (1)

[Scope of Claims] 1. On the surface of a mineral fiberboard with a specific gravity of 0.2 to 0.4, which is produced by wet paper-making of mineral fibers such as rock wool, 2 to 20% of binder is applied to short mineral fibers with a fiber length of 100 to 2000μ. A mineral fiberboard made of a dense skin layer that is blended in a % ratio. 2. The mineral fiberboard according to claim 1, wherein the skin layer is integrally layered on the main body of the mineral fiberboard by laminating. 3. The mineral fiberboard according to claim 1 or 2, wherein the skin layer is integrally layered on the mineral fiberboard main body via a binder. 4. The mineral fiberboard according to any one of claims 1 to 3, wherein the skin layer is integrally layered on both sides of the mineral fiberboard main body.