JP4190468B2 - 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, when the moisture content of the obtained dry board is high, the dry board is likely to be damaged due to insufficient handling strength during handling until the dry board is transported and set in a heat compression apparatus such as a hot press. There was a problem. 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, and has a mineral fiber, an inorganic powder, and a thermosetting resin binder as essential components, and has a multilayer structure capable of forming a decorative layer on its surface with good adhesion. It is an object of the present invention to provide a method for producing an inorganic board that can produce an inorganic board with good handleability in a production process and without causing a puncture phenomenon or deformation.

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 state in which a plurality of wet mats formed by wet papermaking of a slurry prepared by dispersing and laminating are laminated to form a laminated wet mat, and then the inner thermosetting resin binder is completely dissolved in the solvent. to state some of the thermosetting resin binder is not Ji binding force live by drying to the thermosetting resin binder to moisture content condition to be insoluble in the solvent is less than 7 wt% It is formed on a dry board, and the dry board is heated and compressed to cure the thermosetting resin binder.

  The method for producing an inorganic plate according to the invention of claim 2 is characterized in that, in the invention of claim 1, the laminated wet mat is heated and compressed in advance 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 a fourth aspect of the present invention, there is provided a method for producing an inorganic plate according to any one of the first to third aspects, wherein the dry board has a thickness of 1.5 mm to 10 mm and a specific gravity of 0.5 to 1. It is characterized in that the thermosetting resin binder is cured by heating and compression so as to be 8 or less.

  According to the manufacturing method of the inorganic board which concerns on invention of Claim 1, it has sufficient handling intensity | strength, since the laminated wet mat is dried and formed in a dry board so that a moisture content may be less than 7 weight%. When the dry board is transported from the drying device to a heat compression device such as a hot press or set in the heat compression device, it is easy to handle and does not break.

Further, the laminated wet mat is dried in a state in which the thermosetting resin binder inside is completely dissolved in the solvent or in a state in which a part of the thermosetting resin binder is insoluble in the solvent, and the thermosetting resin since the binding force by the coupling agent is formed on a dry board state not Ji live, binding force by binder in the resulting dry board is in a state not live Ji. And, when the thermosetting resin binder is cured in the compressed state when it is heated and compressed in the next step, the bonding force is not developed until it is formed into an inorganic plate having no damage at the bonding portion between the compositions in the dry board. 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.

  According to the method for producing an inorganic board according to the invention of claim 2, in the invention of claim 1, since the laminated wet mat is preliminarily heated and compressed and then dried to form a dry board, the invention of claim 1 above In addition to the above effect, an inorganic plate with better handleability can be produced.

  Moreover, according to the manufacturing method of the inorganic board which concerns on invention of Claim 3, since the water or resin aqueous solution is apply | coated to at least the surface of the dry board before heating compression in invention of Claim 1 or 2, it is an application surface. 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.

  According to the manufacturing method of the inorganic board which concerns on invention of Claim 4, in invention of any one of Claim 1 thru | or 3, thickness is 1.5 mm or more and 10 mm or less, and specific gravity is 0.4 or more. Since it is heat-compressed to 1.8 or less, in addition to the effect of the invention of any one of claims 1 to 3, it is possible to form an inorganic plate that is thin, lightweight, and excellent in strength properties. .

  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 form, and a thermosetting resin binder as an essential component in a lot of water. Is wet-made using a wet paper-making device such as a round net-type wet paper-making device to form two wet mats for the front and back layers. Then, two wet mats for the front and back layers are laminated to form a laminated wet mat consisting of two layers.

  Here, a binder such as a water-soluble binder can be applied to the interface between the two wet mats in order to improve the adhesion between the two layers. The wet mat to be laminated is not limited to two layers, and may be a plurality of layers of three layers or more.

  Hereinafter, the constituent material of the wet mat will be described. Examples of the mineral fibers include rock wool, slug wool, glass wool and the like, and these mineral fibers are 20 to 70 weights with respect to the solid components in the slurry. % 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. 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.

Subsequently, the laminated wet mat having a two-layer structure thus obtained was carried into a hot air circulation dryer, and mixed in the moisture content to be 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. D ) to form a two-layer dryboard.

  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 on the side end surface of the obtained inorganic plate. This is not preferable because the yield is deteriorated. Furthermore, the dry board is not preferable because it may be damaged due to insufficient strength during handling for carrying it to the heat compression apparatus and setting it in the heat compression apparatus.

  In addition, when the curing progresses to the pre-cured state even if the thermosetting resin binder mixed in the wet mat does not completely cure, the thermosetting resin in the front and back layers of the dry board develops a bonding force although it is insufficient. . For this reason, when such a dry board is heat-compressed as will be described later, the once bonded structure is crushed, and the resulting inorganic plate becomes brittle. 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 surface layer of the inorganic board, and the adhesion between the inorganic board and the decorative layer is deteriorated. .

  The laminated wet mat may be preliminarily heated and compressed with a heating roll, continuous press, 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 inside the resulting dry board does not reach a pre-cured state, and for example, as a thermosetting resin When a powdered phenol resin is used, 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 resin is sufficiently cured to form an inorganic plate having a predetermined thickness and specific gravity. Preferably, the dry board is heat-compressed so that the thickness is 1.5 mm or more and 10 mm or less and the specific gravity is 0.5 or more and 1.8 or less, so that a thin inorganic plate that is lightweight and has excellent strength properties can be obtained. Obtainable.

  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 resins in the dry board and the front and back layers have not reached the pre-cured state and the bonding effect is not expressed , these thermosetting resins are compressed by heat compression. Thus, for the first time, the function as a binder is efficiently expressed and cured, and the resulting inorganic plate is not crushed or the like in the inner and front and back layers, and thus 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 starches or polyvinyl alcohol is used together with a thermosetting resin binder, the binding force of the water-soluble binder such as starches or polyvinyl alcohol once applied by drying is applied. It can be softened by moisture, 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 is wet-made by a round net type wet-making machine to obtain two wet mats for the front and back layers, and the two wet mats are laminated to form a two-layer laminate having a moisture content of 80% by weight. A wet mat was obtained.

Next, the laminated wet mat is temporarily pressed through a distance bar having a thickness of 7 mm for 90 seconds at a temperature of 130 ° C. and further carried into a hot-air circulating dryer so that the surface temperature does not exceed 140 ° C. Drying was performed under dry conditions for 20 minutes to obtain a dry board having a water content of 3% by weight. This dry board is in a state where the powder phenolic resin in the inside and the surface layer does not reach the pre-curer (a state where it completely dissolves in the solvent or a part of the thermosetting resin binder becomes insoluble in the solvent) , It was dried to the above moisture content.

Next, the obtained dry board was carried into a hot press apparatus, and after applying water of 100 g / m ^{2 on} one side to the front and back surfaces, it was set between the hot plates of the hot press apparatus, and the thickness was 3.5 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 3.5 mm and a specific gravity of 1.2. 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 3 mm, and the bending strength and plane peel strength were measured. The bending strength was 20 N / mm ² and the plane peel strength was 1. It was 5 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 two-layer laminated wet mat obtained in the above example was dried with a dryer at 200 ° C. for 25 minutes to obtain a dry board having a moisture content of 1% by weight. Next, this dry board was heated and compressed by a hot press in the same manner as in the above example to form an inorganic plate according to a comparative example having a thickness of 3.5 mm and a specific gravity of 1.2.

This inorganic plate was sanded in the same manner as in the example to form a thickness of 3 mm, and the bending strength and plane peel strength were measured. The example was obtained with a bending strength of 9 N / mm ² and a plane peel strength of 0.5 N / mm ^2. It was inferior to. Moreover, when a polyolefin decorative sheet was stuck on the surface to form an inorganic decorative board, and a cross-cut test (peeling test test) was performed according to JIS K 5600 (Paint General Test Method), from the surface layer of the inorganic board The substrate peeled and the adhesion between the inorganic board and the decorative layer was poor.

Claims (4)

Laminated wet mats are formed by laminating multiple layers of wet mats formed by wet paper-making slurry prepared by mixing and dispersing raw materials containing mineral fiber, inorganic powder and thermosetting resin binder as essential components in water. Formed into
Next, the moisture content of the laminated wet mat becomes less than 7% by weight when the thermosetting resin binder inside is completely dissolved in the solvent or when a part of the thermosetting resin binder is insoluble in the solvent. and dried to form a dry board state no Ji raw bonding force due to the thermosetting resin binder so,
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 the laminated wet mat 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.   The dry board is heated and compressed so as to have a thickness of 1.5 mm to 10 mm and a specific gravity of 0.5 to 1.8 to cure the thermosetting resin binder. The manufacturing method of the inorganic board of any one of Claims 1.