JP4190467B2 - Manufacturing method of inorganic board - Google Patents

Description

  INDUSTRIAL APPLICABILITY The present invention is an inorganic material capable of producing with good productivity an inorganic board having good adhesion to a decorative layer suitable for use as a decorative board substrate for interior materials, building materials, opening members, furniture, etc. of buildings such as houses. The present invention relates to a method for manufacturing a plate.

  Conventionally, gypsum boards and plywood have been used as substrates and base materials for interior decorative materials for buildings such as houses. However, the gypsum board is heavy and difficult to construct, and when water is absorbed, strength properties such as bending strength are significantly reduced. On the other hand, the plywood is light and easy to construct, but has the disadvantages that it is easy to burn and rot.

  For this reason, as described in Patent Document 1, the present applicant formed a laminate in which a lightweight middle layer was sandwiched between front and back layers in a sandwich shape, and then compressed and molded with a press, and then dried the binder. A method for producing a lightweight, high-strength, three-layer inorganic board to be cured was proposed.

  However, in the above method, in the drying process after being compressed with a press, a so-called springback phenomenon occurs in which the mineral fibers compressed on the front and back layers rebound to return to the original shape, and the surface of the obtained inorganic plate is uneven. As a result, the smoothness sometimes deteriorated.

  For this reason, when such an inorganic board is used as a substrate for a decorative board, if a decorative layer is directly provided on the surface by applying a decorative sheet or decorative paper, or by painting, printing, etc., the surface irregularities are formed on the decorative layer surface. It sometimes appeared as irregularities and worsened the decorative appearance. Therefore, it is necessary to provide a decorative layer after sanding the surface to make it smooth, but it requires a sanding process and has unevenness on the surface, resulting in poor productivity such as increased grinding amount and reduced yield, Further, since many of the dense and hard surface layers are scraped off, there is a problem that strength properties such as bending strength and hardness are deteriorated.

Therefore, as described in Patent Document 2, the present applicant has proposed a method for producing an inorganic board in which a wet mat is once dried and then hot pressed to completely cure the binder.
JP-A-5-50417 JP 2003-251617 A

  However, in this method, especially in the case of a three-layer structure, the strength of the lightweight intermediate layer of the dry board formed by drying is low, so if the resulting dry board has a high moisture content, There was a problem that the dry board was likely to be damaged due to insufficient handling strength during handling until it was transported and set in the heat compression apparatus. In addition, puncture phenomenon may occur due to abrupt evaporation of moisture contained in the dry board during heating and compression, and the side end face of the resulting inorganic board may be deformed into a curved shape, resulting in productivity and production yield. There was a problem of lowering.

  On the other hand, in order to prevent the occurrence of such insufficient handling strength and puncture phenomenon, it may be possible to dry strongly to reduce the moisture content in the dry board. When a decorative layer is provided on the surface of a dried inorganic plate by attaching a decorative sheet or the like, there is a problem that the decorative layer is easily peeled off from the inorganic plate.

As a result of diligent investigation on such problems, the thermosetting resin binder on the surface of the dry board does not reach a completely cured state by drying, but is in a precured state (mostly insoluble in a solvent) or a state close thereto. When the mineral fiber and the inorganic powder are in a semi-bonded state after curing and heating and compressing, the above-mentioned semi-bonded state is broken by this compressive force, and an inorganic plate whose surface is fragile is obtained. It was found that the decorative layer provided on the surface of the plate was easily peeled off due to poor adhesion to the inorganic plate.

  The present invention has been made based on such knowledge, front and back layers having mineral fibers, inorganic powder and thermosetting resin binder as essential components, and an inorganic foam and binder between the front and back layers. A three-layered inorganic board with a light-weight intermediate layer containing at least an essential component and capable of forming a decorative layer on the surface with good adhesion, with good handling in the production process, and causing puncture and deformation It aims at providing the manufacturing method of the inorganic board which can be manufactured without it.

In order to achieve the object of the present invention, a method for producing an inorganic board according to the invention of claim 1 comprises mixing raw materials containing mineral fiber, inorganic powder and thermosetting resin binder as essential components in water. A lightweight intermediate layer composition comprising a raw material containing at least an inorganic foam and a binder as an essential component is disposed in the middle of a front and back layer wet mat formed by wet-making a slurry composition prepared by dispersing. A wet mat having a three-layer structure is formed, and then the wet mat having the three-layer structure is completely dissolved in a solvent or a part of the thermosetting resin binder in the front and back layers. in a state that becomes insoluble in the solvent and dried as the moisture content is less than 7% by weight to form a dry board state not Ji raw bonding force due to the thermosetting resin binder, heating compressing the dry board And heat curing Characterized in that the resin is cured binder.

  According to a second aspect of the present invention, there is provided a method for producing an inorganic plate according to the first aspect of the present invention, wherein a wet mat having a three-layer structure is preliminarily heated and compressed and then dried to form a dry board.

  The method for producing an inorganic plate according to the invention of claim 3 is characterized in that, in the invention of claim 1 or 2, water or a resin aqueous solution is applied to at least the surface of the dry board and then heated and compressed.

  According to the method for manufacturing an inorganic board according to the invention of claim 1, since a wet mat having a three-layer structure is dried and formed into a dry board so that the moisture content is less than 7% by weight, sufficient handling strength is obtained. When the dry board is transported from the drying apparatus to a heating and compression apparatus such as a hot press or set in the heating and compression apparatus, it is easy to handle and does not cause damage.

Also, the wet mat having a three-layer structure is dried in a state where the thermosetting resin binder in the front and back layers is completely dissolved in the solvent or in a state where a part of the thermosetting resin binder is insoluble in the solvent. since bonding strength due to the thermosetting resin binder is formed on a dry board state not Ji live, the front and back layers of the resulting dry board in a state not binding force by binder raw Ji. And, when the thermosetting resin binder is cured in the compressed state when heated and compressed in the next step, the bonding force is not developed until it is formed into an inorganic plate that is not damaged at the bonding portion between the compositions constituting the front and back layers. As a result, even when a decorative layer is provided on the surface, an inorganic plate that does not peel off the decorative layer can be formed.

  The method for producing an inorganic board according to the invention of claim 2 is the invention of claim 1, wherein the wet mat having a three-layer structure is pre-heated and compressed and then dried to form a dry board. In addition to the effects of the invention, an inorganic plate with better handleability can be produced.

  Moreover, the manufacturing method of the inorganic board which concerns on invention of Claim 3 is the invention of Claim 1 or 2. Since water or the resin aqueous solution is apply | coated to at least the surface of the dry board before heat compression, only an application surface is applied. In addition to the effects of the first or second aspect of the invention, an inorganic plate with better surface smoothness can be produced by heat compression.

  Hereinafter, embodiments of the present invention will be described in detail. The following description of the preferred embodiment is exemplary and is not intended to limit the invention in any way.

  First, the manufacturing method of the inorganic board concerning this embodiment is the slurry composition which disperse | distributed and mixed the raw material which contains a mineral fiber, an inorganic powder, and a thermosetting resin binder as an essential component in a lot of water. Is wet-made using a wet papermaking apparatus such as a round net-type wet papermaking apparatus to form a wet mat for the front and back layers. On the other hand, a lightweight intermediate layer composition made of a raw material containing at least an inorganic foam and a binder as essential components is spread and deposited between the front and back layer wet mats to form a three-layer wet mat as an intermediate layer. To do. An aqueous binder solution can be applied to the interface between the wet mat for the front and back layers and the intermediate layer in order to improve the adhesion between the two layers.

  Hereinafter, the constituent materials of the front and back layers will be described. Examples of the mineral fibers include rock wool, slug wool, glass wool, etc., and these mineral fibers are based on the solid components in the slurry for the front and back layers. 20-70% by weight is added. When the addition amount is less than 20% by weight, the entanglement between the mineral fibers is reduced and the bending strength is weakened. When the addition amount is more than 70% by weight, the addition ratio of the inorganic powder is reduced, and the surface denseness is reduced. Since it becomes low and cosmetics are impaired, it is not preferable.

  As the inorganic powder, calcium carbonate, micro silica, aluminum hydroxide, slag powder or the like can be used, and 10 to 70% by weight is added as a solid component in the slurry for the front and back layers. When the addition amount is less than 10% by weight, the density of the formed inorganic board surface is lowered and the cosmetic properties are impaired. When the addition amount is more than 70% by weight, the addition ratio of mineral fibers is reduced and the bending strength is weak. This is not preferable.

  Further, as the thermosetting resin binder, a powdered form such as phenol resin, melamine resin, urea melamine resin, or an aqueous binder can be used. In addition, water-soluble or water-dispersible binders such as polyvinyl alcohol, starches, polyacrylamide, SBR latex, and acrylic resin emulsion can be used in combination with the thermosetting resin.

  Such a binder is added in a total amount of about 2 to 20% by weight, preferably about 7 to 15% by weight, based on the solid components in the slurry for the front and back layers. If the addition amount of the binder is less than 2% by weight, the strength properties such as bending strength are lowered, and if it exceeds 20% by weight, the fireproof property is deteriorated.

  In addition, synthetic resin fibers such as polypropylene, polyester, and vinylon, plant fibers such as hemp and wood fibers, flocculants, sizing agents, antifoaming agents, and the like can be added to the slurry as necessary.

  Next, the constituent materials of the composition for the intermediate layer will be described. Examples of the inorganic foam include pearlite, shirasu foam, silica flour, and glass foam. The main raw material for the intermediate layer is the entire intermediate layer. 40 to 90% by weight can be added. If it is less than 40% by weight, the weight reduction becomes insufficient, and if it exceeds 90% by weight, the strength becomes weak.

  As the binder for the intermediate layer, those that can be used in the slurry composition for the front and back layers, that is, thermosetting resin binder, polyvinyl alcohol, starch, polyacrylamide, SBR latex, acrylic resin emulsion, etc. 2 to 20 wt% can be added as a solid component to the solid component of the layer composition.

  In addition, as another intermediate layer composition, the same mineral fiber and wood fiber as the slurry composition for the front and back layers can be added at a ratio of less than 50% by weight. In addition, in such a composition for the intermediate layer, in order to prevent scattering of fine details in the air and improve the deposition efficiency, about 5 to 30% by weight of water is added. It is preferable to include it.

Subsequently, the wet mat having a three-layer structure thus obtained was carried into a hot air circulation dryer, and mixed in the front and back layers so that the moisture content was less than 7% by weight, preferably less than 4% by weight. To prevent the thermosetting resin binder from reaching a precure state ( so that the thermosetting resin binder is completely dissolved in the solvent or a part of the thermosetting resin binder is insoluble in the solvent. To dry ) to form a dry board.

  Here, when the moisture content of the dry board is 7% by weight or more, a puncture phenomenon occurs during heat compression in the heat compression step described later, or a curved deformation occurs in the side end surface of the obtained inorganic plate, resulting in a yield. In addition, the dry board is not preferable because it may be damaged due to insufficient strength during handling for carrying the dry board to the heating compression apparatus and setting it in the heating compression apparatus.

  In addition, when the curing progresses to a precure state until the thermosetting resin binder mixed in the front and back layers is not completely cured, the thermosetting resin of the dry board front and back layers develops a bonding force, although insufficient. For this reason, when such a dry board is heated and compressed as will be described later, the once-bonded structure is crushed, and the front and back layers of the resulting inorganic board are weakened. As a result, when a decorative layer is provided on the surface of such an inorganic board, the decorative layer is easily peeled off from the weakened front and back layers of the inorganic board, and the adhesion between the inorganic board and the decorative layer is deteriorated. .

  The three-layer wet mat may be preliminarily heated and compressed with a heating roll, a continuous press, a flat plate press or the like and then dried with the hot air circulation dryer to form a dry board. As described above, by performing preliminary heating and compression before drying, it is possible to form a dry board having further excellent handling strength.

  The drying conditions and preliminary heat compression conditions are not particularly limited as long as the thermosetting resin of the front and back layers of the obtained dry board does not reach a pre-cured state, and for example, thermosetting When a powdered phenol resin is used as the resin, the time can be adjusted under conditions of a drying temperature of 60 ° C to 140 ° C and a preliminary heating and compression temperature of 80 ° C to 180 ° C.

  Next, the dry board obtained in this way is inserted between the heating plates of a heating and compression device such as a multistage hot press, and is heated and compressed at a temperature equal to or higher than the curing temperature of the thermosetting resin binder, and is thermally cured. The adhesive resin is sufficiently cured to form an inorganic plate having a predetermined thickness.

  Here, since the moisture content of the dry board is adjusted to less than 7% by weight, preferably less than 4% by weight, handling such as transportation to the heating and compression apparatus or setting between the heating plates without breakage is handled. In addition, heating and compression can be performed with high productivity without causing a puncture phenomenon or a curved deformation of the end face on the inorganic plate side.

In addition, since the thermosetting resin on the front and back layers of the dryboard has not reached the pre-cured state and its bonding effect is not expressed , the thermosetting resin on the front and back layers of the dryboard is compressed by heat compression. In this state, the function as a binder is efficiently expressed and cured for the first time, and the surface layer of the resulting inorganic plate is not crushed and the surface layer is not weakened. For this reason, when a surface decorative layer is provided on the surface of such an inorganic plate by sticking, painting, printing or the like of a veneer or a decorative sheet, the inorganic plate and the decorative layer are not peeled off. be able to.

  In addition, water or resin aqueous solution can be apply | coated to the surface or front / back surface of a dry board before the heat compression by the said multistage type hot press. By applying such moisture, the front and back layers coated with moisture can be softened and the moldability by heat compression can be improved. In particular, when a water-soluble binder such as starch or polyvinyl alcohol is used together with a thermosetting resin on the front and back layers, the binding force of the water-soluble binder such as starch or polyvinyl alcohol once applied by drying is applied. It can be softened by water, and an inorganic plate with good formability and good surface properties can be formed by subsequent heat compression.

  In addition, during the heat compression, the surface of the dry board can also be heat compressed using an emboss plate. In this case, an inorganic plate having an arbitrary uneven pattern engraved on the surface can be obtained.

(Example)
50% by weight of slag wool, 39% by weight of aluminum hydroxide, 6% by weight of powdered phenolic resin, 4% by weight of starch, 1% by weight of polyester fiber which is a heat-sealing fiber, and a large amount of raw material with a small amount of flocculant added The mixture was added to water and stirred to obtain a slurry for front and back layers having a solid content concentration of about 3% by weight. Next, this slurry was subjected to wet papermaking using a round net type wet papermaking apparatus to obtain a wet mat for front and back layers having a water content of 80% by weight.

  On the other hand, 55% by weight of pearlite, 34% by weight of aluminum hydroxide, 6% by weight of powdered phenolic resin, 4% by weight of starch, 1% by weight of polyester fiber as a heat-sealing fiber, and 20% by weight of these solid components The intermediate layer composition is prepared by uniformly mixing while spraying water, and the intermediate layer composition is uniformly sprayed and deposited on the back layer wet mat, and the surface layer wet is applied to the spray surface. The mats were laminated to form a three-layer wet mat.

Next, this wet mat having a three-layer structure is temporarily pressed for 90 seconds at a temperature of 130 ° C. through a 7 mm-thickness bar, and is further carried into a hot-air circulating dryer so that the temperature of the surface layer is 140. Drying was performed for 20 minutes under drying conditions not exceeding ℃, and a dry board having a water content of 3% by weight was obtained. This dry board has the above-mentioned water content in a state where the powder phenolic resin of the surface layer does not reach the pre-cure (a state where it is completely dissolved in the solvent or a part of the thermosetting resin binder is insoluble in the solvent). Was dry to the rate.

Next, the obtained dry board was carried into a hot press apparatus, and water of 100 g / m ^{2 on} one side was applied to the front and back surfaces, respectively, and then set between hot plates of the hot press apparatus, and the thickness was 6.6 mm. It was heated and compressed for 5 minutes under a temperature condition of 200 ° C. through a distance bar to obtain an inorganic plate having a thickness of 6.6 mm and a specific gravity of 0.71. The dry board was able to be carried into a hot press and set between hot plates satisfactorily without causing damage or the like. Moreover, the puncture phenomenon did not occur at the time of heat compression, and the inorganic plate after heat compression was not deformed.

The inorganic plate thus obtained was lightly sanded on the front and back surfaces to form a thickness of 6 mm, and its bending strength and plane peel strength were measured. The bending strength was 14 N / mm ² and the plane peel strength was 0. It was 9 N / mm ² . Moreover, when a polyolefin decorative sheet was stuck on the surface to form an inorganic decorative board, and a cross-cut test (peeling test) was performed according to JIS K 5600 (Paint General Test Method), The adhesion between the inorganic board and the decorative layer was good without causing substrate peeling.

(Comparative example)
The three-layer wet mat obtained in the above example was dried with a dryer at 200 ° C. for 20 minutes to obtain a dry board having a moisture content of 3% by weight. Subsequently, this dry board was heated and compressed by a hot press in the same manner as in the above example, to obtain an inorganic plate according to a comparative example having a thickness of 6.6 mm and a specific gravity of 0.71.

When this inorganic plate was sanded in the same manner as in the example to form a thickness of 6 mm and the bending strength and plane peel strength were measured, the bending strength was 9 N / mm ² and the plane peel strength was 0.5 N / mm ² . The strength properties were inferior to those of the examples. In addition, a polyolefin decorative sheet was stuck on the surface to form an inorganic decorative board, and a cross-cut test (peeling test test) was conducted according to JIS K 5600 (Paint General Test Method). Substrate peeling occurred, and the adhesion between the inorganic board and the decorative layer was poor.

Claims (3)

In the middle of the wet mat for the front and back layers formed by wet-making a slurry composition prepared by mixing and dispersing raw materials containing mineral fiber, inorganic powder and thermosetting resin binder as essential components in water, A lightweight intermediate layer composition made of a raw material containing at least an inorganic foam and a binder as essential components is arranged to form a three-layer wet mat,
Next, the moisture content of the three-layer wet mat is such that the thermosetting resin binder in the front and back layers is completely dissolved in the solvent or part of the thermosetting resin binder is insoluble in the solvent. and dried to be less than 7% by weight to form a dry board state not Ji avidity live by the thermosetting resin binder,
A method for producing an inorganic board, wherein the dry board is heated and compressed to cure the thermosetting resin binder.   The method for producing an inorganic board according to claim 1, wherein a wet mat having a three-layer structure is heated and compressed in advance and then dried to form a dry board.   The method for producing an inorganic board according to claim 1 or 2, wherein water or a resin aqueous solution is applied to at least a surface of the dry board and then heated and compressed.