Incombustible coating, method for preparing incombustible coating, incombustible plate material, and method for manufacturing incombustible plate material

Abstract

To inexpensively form a coating film layer excellent in gas barrier property and incombustibility without causing lowering of coating film strength and deterioration of water resistance.SOLUTION: An incombustible coating, which is formed by mixing dispersion liquid that is prepared by dispersing montmorillonite particles having an aspect ratio of 100 or more and 300 or less and has viscosity of 4,000 mPa s or more, and an emulsion resin, is used for forming a coating film layer 30.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a non-combustible paint, a method for adjusting the non-combustible paint, a non-combustible board material, and a method for manufacturing the non-combustible board material.

Background Art

[0002] Conventionally, halogen-based flame retardants have been widely used as flame retardants for making paint compositions flame-retardant. However, there are problems with dioxins and chlorofluorocarbons generated from these halogen-based flame retardants, and they are not favorable in terms of environmental protection.

[0003] In addition, inorganic flame retardants such as aluminum hydroxide are also used. However, aluminum hydroxide has problems such as a decrease in the physical properties and water resistance of the paint and the substrate to which it is applied.

[0004] In addition, in order to form a flame-retardant layer by applying it to an inorganic board for construction, a flame retardant containing a swelling inorganic compound as an essential component has been studied. However, there is a problem that the viscosity becomes too high due to the action with other components such as water-soluble polymers, resulting in a decrease in coatability.

[0005] Therefore, conventionally, as shown in, for example, Patent Document 1, a non-combustible paint composition has been proposed in which the gas barrier property and non-combustibility are improved by containing fine powder of high-purity purified bentonite (see Patent Document 1 below).

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] Incidentally, the gas barrier property (non-combustibility) is exhibited by the maze effect due to the lamination of thin clay crystals of montmorillonite, which is a layered clay mineral contained in bentonite. To improve the gas barrier property (non-combustibility), it is necessary for montmorillonite particles to overlap in multiple layers in a layered manner. For this purpose, it is necessary that the montmorillonite particles are sufficiently exfoliated (separated between layers) and well dispersed in the non-combustible paint.

[0008] However, in the conventional dispersion treatment method of stirring a bentonite suspension with a propeller stirrer or the like, the montmorillonite particles cannot be exfoliated thinly to near the unit crystal (one layer), and the montmorillonite particles in the bentonite suspension become thick. Therefore, only a coating film layer with low gas barrier property and non-combustibility with a small number of stacked montmorillonite particles could be formed.

[0009] It may be considered to improve the gas barrier property by increasing the coating amount of the non-combustible paint, but there is a problem that it leads to an increase in manufacturing cost and a deterioration in non-combustibility due to an increase in the resin amount. Also, it may be considered to improve the gas barrier property by increasing the content of bentonite in the non-combustible paint, but there is a problem that it leads to a decrease in the coating film strength due to a decrease in the ratio of the emulsion resin and a deterioration in water resistance due to an increase in swelling montmorillonite. Furthermore, it may be considered to improve the gas barrier property by using fine powder of bentonite containing montmorillonite particles having a long length in the layer plane direction (for example, 300 nm to 500 nm) and a large aspect ratio (for example, about 380), but such fine powder of bentonite is expensive, so there is a problem that the non-combustible paint and the non-combustible plate material become expensive.

[0010] An object of the present invention is to be able to inexpensively form a coating film layer excellent in gas barrier property and non-combustibility without causing a decrease in coating film strength and a deterioration in water resistance.

Means for Solving the Problem

[0011] In order to achieve the above object, in the present invention, a non-combustible paint containing a dispersion liquid with a viscosity of 4000 mPa·s or more in which particles of a layered clay mineral having an aspect ratio of 100 or more and 300 or less are dispersed is used for forming the coating film layer.

[0012] Specifically, a first invention is a non-combustible paint for forming a coating film layer, characterized in that a dispersion liquid with a viscosity of 4000 mPa·s or more in which particles of a layered clay mineral having an aspect ratio of 100 or more and 300 or less are dispersed is mixed with an emulsion resin.

[0013] Further, a second invention is characterized in that, in the first invention, the layered clay mineral is montmorillonite.

[0014] Here, the viscosity refers to the viscosity measured by a B-type viscometer in accordance with JIS Z8803.

[0015] Further, the aspect ratio is the ratio of the length in the plane direction to the thickness of the particles of the layered clay mineral (montmorillonite in the second invention). Here, it refers to the average value of the aspect ratios of 100 randomly selected particles of the layered clay mineral in the dispersion liquid. Furthermore, the “dispersion liquid with a viscosity of 4000 mPa·s or more in which particles of a layered clay mineral having an aspect ratio of 100 or more and 300 or less are dispersed” means a dispersion liquid in which particles of a layered clay mineral having an aspect ratio of 100 or more and 300 or less when ideally dispersed (exfoliated to near the unit crystal) are dispersed and the viscosity is 4000 mPa·s or more. The aspect ratio of the particles of the layered clay mineral is obtained by drying the dispersion liquid, measuring the area and thickness of the plane of each particle of the layered clay mineral with an AFM (Atomic Force Microscope), taking the diameter of the circle with an area corresponding to the measured area as the length in the plane direction, and calculating from the length in the plane direction and the measured thickness.

[0016] In the first and second inventions, the non-combustible paint for forming the coating film layer contains a dispersion having a viscosity of 4000 mPa·s or more in which particles of a layered clay mineral (montmorillonite in the second invention) having an aspect ratio of 100 or more and 300 or less are dispersed. The inventors of the present application conducted a heat generation test using a cone calorimeter on a non-combustible plate material formed with a coating film layer by the above non-combustible paint, and measured the total heat generation amount for 20 minutes from the start of heating. As a result, the total heat generation amount was 3.4 MJ / m 2 or less. When the same test was conducted using a conventional non-combustible paint (dispersion viscosity: 2320 mPa·s) in which the dispersion treatment method for the same particles of the layered clay mineral was stirring, the result (4.6 MJ / m 2 ) was 1.2 MJ / m 2 or more lower. That is, it was found that by using a non-combustible paint containing a dispersion having a viscosity of 4000 mPa·s or more in which particles of a layered clay mineral having an aspect ratio of 100 or more and 300 or less are dispersed, a coating film layer excellent in gas barrier properties and non-combustibility can be formed. Further, in the above non-combustible paint, the gas barrier property can be improved without increasing the content of the layered clay mineral, so that it does not lead to a decrease in the coating film strength or deterioration of the water resistance. In addition, a relatively inexpensive layered clay mineral having an aspect ratio of 100 or more and 300 or less can be used. Therefore, according to the non-combustible paint according to the first and second inventions, a coating film layer excellent in gas barrier properties and non-combustibility can be formed at low cost without causing a decrease in the coating film strength or deterioration of the water resistance. Further, by using the non-combustible paint according to the first and second inventions, when manufacturing a non-combustible plate material, the range of variations in the surface finishing can be expanded. For example, it becomes possible to use a veneer of a broad-leaved tree having a high specific gravity and a large organic content, or to apply a coating to the veneer surface.

[0017] The third invention is a method for preparing a non-combustible paint for forming a coating film layer, which comprises a high-pressure dispersion treatment step of applying pressure to a suspension in which particles of a layered clay mineral are mixed in a water-soluble solvent by a high-pressure dispersion device and ejecting the suspension from a gap, so that a pressure of 100 MPa or more is applied to the suspension during ejection to disperse the particles of the layered clay mineral having an aspect ratio of 100 or more and 300 or less to produce a dispersion having a viscosity of 4000 mPa·s or more, and a mixing step of mixing an emulsion resin with the dispersion produced in the high-pressure dispersion treatment step.

[0018] The fourth invention is the third invention, wherein the layered clay mineral is montmorillonite, and in the high-pressure dispersion treatment step, a fine powder of bentonite is mixed with the dispersion to prepare the suspension.

[0019] In the third and fourth inventions, a suspension in which particles of a layered clay mineral (montmorillonite in the fourth invention) are mixed in a water-soluble solvent is subjected to a high-pressure dispersion treatment by applying pressure with a high-pressure dispersion device and ejecting it from a gap, so that a pressure of 100 MPa or more is applied to the suspension at the time of ejection. According to such a high-pressure dispersion treatment, the particles of the layered clay mineral in the suspension collide with each other and apply a shearing force to each other, causing cleavage (separation between layers) in the particles of the layered clay mineral. In the third invention, by applying a high pressure of 100 MPa or more to the suspension at the time of ejection of the suspension, the particles of the layered clay mineral are easily cleaved until they become close to a unit crystal (one layer) in a short time. Therefore, the particles of the layered clay mineral contained in the dispersion liquid after the high-pressure dispersion treatment become extremely thin and have a high aspect ratio. When the particles of the layered clay mineral are cleaved until they become close to a unit crystal (one layer), the relative amount of the particles of the layered clay mineral contained in the dispersion liquid increases, so that the viscosity of the dispersion liquid increases and the particles of the layered clay mineral are likely to overlap in layers to form a multilayer structure. Therefore, the gas barrier property of the coating film layer formed by the non-combustible paint is improved and the non-combustibility is enhanced. Thus, according to the third and fourth inventions, a non-combustible paint containing a dispersion liquid having a viscosity of 4000 mPa·s or more in which particles of a layered clay mineral having an aspect ratio of 100 or more and 300 or less are dispersed can be easily adjusted. Therefore, a coating film layer excellent in gas barrier property and non-combustibility can be formed at low cost without causing a decrease in coating film strength or deterioration of water resistance.

[0020] The fifth invention is a non-combustible plate material in which a coating film layer made of a non-combustible paint composition is formed on one side or both sides of a building base material, the coating film layer contains particles of a layered clay mineral having an aspect ratio of 100 or more and 300 or less, and the non-combustible plate material has a total calorific value of 3.4 MJ / m in the calorific value test for 20 minutes. 2 It is characterized by being as follows.

[0021] The sixth invention is characterized in that, in the fifth invention, the layered clay mineral is montmorillonite.

[0022] Here, the heat generation test refers to the heat generation test using a cone calorimeter in accordance with JIS A1316.

[0023] In the fifth and sixth inventions, the non-combustible plate material forms a coating film layer containing particles of a layered clay mineral (montmorillonite in the sixth invention) with an aspect ratio of 100 or more and 300 or less on one or both sides of the building base material, so that the total heat generation amount in the heat generation test for 20 minutes is 3.4 MJ / m 2 It is configured as follows. This total heat generation amount is the result (4.6 MJ / m 2 ) when the same test is conducted using a conventional non-combustible paint (dispersion viscosity 2320 mPa·s) in which the dispersion treatment method for particles of the same layered clay mineral is stirring. It is 1.2 MJ / m 2 Lower or more, and the above non-combustible plate material is excellent in non-combustibility. Further, in the fifth and sixth inventions, the coating film layer contains particles of a layered clay mineral with an aspect ratio of 100 or more and 300 or less, and such a coating film layer can be formed at a relatively low cost. Therefore, according to the fifth and sixth inventions, a non-combustible plate material excellent in non-combustibility can be provided at low cost. Also, if the non-combustible plate material according to the fifth and sixth inventions is used, the total heat generation amount in the heat generation test is low, and even if a combustible decorative process is applied to the surface, it is easy to satisfy the performance requirement contents (total heat generation amount 8.0 MJ / m 2 or less) required by the Building Standards Law as a flame-retardant material, semi-non-combustible material, and non-combustible material. Therefore, it becomes possible to apply various decorative processes to the surface, and a plate material excellent not only in non-combustibility but also in design can be provided.

[0024] The seventh invention is a method for manufacturing a non-combustible plate material in which a coating film layer made of a non-combustible paint composition is formed on one or both sides of a building base material, and by the adjustment method according to the third or fourth invention, a paint adjustment step of adjusting a non-combustible paint containing the non-combustible paint composition, and the non-combustible paint adjusted in the paint adjustment step is applied to one or both sides of the building base material at 100 g / m 2 or more and 300 g / m 2 or less to form the coating film layer, and is characterized by comprising a coating step.

[0025] In the seventh invention, a non-combustible paint adjusted by the adjustment method according to the third or fourth invention is applied to one or both sides of a building base material in an amount of 100 g / m 2 or more and 300 g / m 2 or less. By this application, a coating film layer excellent in gas barrier properties and non-combustibility can be formed on one or both sides of the building base material at low cost without causing a decrease in coating film strength or deterioration of water resistance. Therefore, according to the manufacturing method of the seventh invention, a non-combustible plate material excellent in non-combustibility can be provided at low cost.

Effects of the Invention

[0026] As described above, according to the present invention, in forming the coating film layer, a non-combustible paint containing a dispersion liquid having a viscosity of 4000 mPa·s or more in which particles of a layered clay mineral having an aspect ratio of 100 or more and 300 or less are dispersed is used. Therefore, a coating film layer excellent in gas barrier properties and non-combustibility can be formed at low cost without causing a decrease in coating film strength or deterioration of water resistance.

Brief Description of the Drawings

[0027]

Figure 1

Figure 2

Modes for Carrying Out the Invention

[0028] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The following description of the preferred embodiments is merely illustrative in nature and is not intended to limit the present invention, its applications, or its uses.

[0029] FIG. 1 shows a non-combustible plate material 1 using a non-combustible paint composition according to an embodiment of the present invention. This non-combustible plate material 1 is used as a non-combustible building material such as a wall material of a building and forms a fire-resistant structure.

[0030] In this embodiment, the non-combustible plate material 1 includes a building base material 10, a sealer layer 20, and a coating film layer 30. The building base material 10 is, for example, in the shape of a rectangular plate-like body, and the sealer layer 20 is formed on one surface thereof, which is the surface, by an undercoat paint. The coating film layer 30 is formed on the sealer layer 20 by a topcoat paint. Although details will be described later, the topcoat paint is a non-combustible paint according to the present invention, and the coating film layer 30 has a non-combustible paint composition included in the non-combustible paint according to the present invention.

[0031] In addition, in this embodiment, the non-combustible plate material 1 is not a non-combustible material in the standard that meets the standards of the Building Standards Law, but includes a quasi-non-combustible material, a semi-non-combustible material, and a non-combustible material in the standards of the Building Standards Law, and is used in the sense of "difficult to burn". Further, the "fire-resistant structure" is not a fire-resistant structure in the standard that meets the standards of the Building Standards Law, but includes a fireproof structure, a quasi-fire-resistant structure, and a fire-resistant structure in the standards of the Building Standards Law, and is used in the sense of "difficult to burn structure".

[0032] (Building base material) As the building base material 10, a plate material having flame retardancy, quasi-flame retardancy, or flame retardancy defined by the Building Standards Law is used. For example, inorganic materials such as volcanic glass multi-layer plates, calcium silicate plates, and gypsum boards, metal plates, resin plates, etc. can be appropriately selected. And although these materials inherently have the property of being difficult to burn (flame retardancy and quasi-flame retardancy), by forming the coating film layer 30 having a non-combustible paint composition on their surfaces (to become the non-combustible plate material 1), in addition to the original properties, the degree of difficulty in burning is further increased by the synergistic effect of the coating film layer 30.

[0033] The building base material 10 is, for example, 50 kW / m in radiant heat quantity 2When heated under the conditions and deformed such as shrinking or stretching, it is desirable that the degree of deformation does not reach the level where the coating film layer 30 on the surface is damaged. This is because if such deformation occurs, the coating film layer 30 will be torn, and the flame-retardant function and effect of the coating film layer 30 will decrease. As such a building base material 10, for example, a volcanic glass multi-layer board with a thickness of 6 mm to 12 mm (JIS A 5440) (trade name "Dailite" of Dai Ken Kogyo Co., Ltd.), a semi-incombustible calcium silicate board with a thickness of 9 mm (trade name "Anshin" of Nichiha Corporation), or a non-combustible calcium silicate board with a thickness of 6 mm (trade name "Hi-Lac" of A&A Material Co., Ltd.) etc. are preferably used.

[0034] (Sealer layer) The sealer layer 20 is formed by applying an undercoat paint to the surface of the building base material 10. The sealer layer 20 is formed to achieve both making the surface of the building base material 10 a smooth surface and preventing the non-combustible paint composition that will become the coating film layer 30 from unevenly soaking into the building base material 10. By forming the sealer layer 20 on the surface of the building base material 10 to make the surface a smooth surface, the coating film layer 30 thereon can be formed into a uniform and beautiful non-combustible coating film layer.

[0035] Note that the formation of the sealer layer 20 is not essential and can be appropriately carried out as needed. If there is other smoothing treatment that can make the surface of the building base material 10 a smooth surface, that can also be adopted. Also, if the surface of the building base material 10 is originally a smooth surface, the non-combustible paint can be directly applied to the surface to form the coating film layer 30 without forming the sealer layer 20. However, considering that the smoothing of the surface of the building base material 10, preventing the uneven soaking of the non-combustible paint, and the adhesion between the coating film layer 30 made of the non-combustible paint composition and the building base material 10 can be achieved together, it is desirable to form the sealer layer 20.

[0036] The type of the sealer layer 20 is not particularly specified, and various synthetic resins such as acrylic resin, urethane resin, epoxy resin, vinyl chloride resin, silicone resin, and mixtures thereof are used. Further, various inorganic pigments, auxiliaries, etc. can be added to the sealer layer 20 as required.

[0037] The coating amount of the sealer layer 20 is, for example, 10 g / m 2 or more and 100 g / m 2 or less is preferable. Further, the coating method of the sealer layer 20 is not particularly specified, and known methods such as roll coater, flow coater, spray, etc. may be used. Also, the drying and curing method can be performed by a known method such as a hot air dryer.

[0038] (Coating film layer) The coating film layer 30 is formed by applying a topcoat paint on the sealer layer 20. The topcoat paint is a non-combustible paint according to the present invention adjusted by mixing an emulsion resin into a bentonite dispersion in which fine powder of bentonite is dispersed in a water-soluble solvent. The coating film layer 30 contains bentonite particles (mainly montmorillonite particles) and the solid content of the emulsion resin as a non-combustible paint composition.

[0039] [Non-combustible paint] In the present embodiment, a mixture of the above-mentioned bentonite dispersion and emulsion resin in a weight ratio of 8 to 2 is used as the non-combustible paint for forming the coating film layer 30.

[0040] Bentonite is a weakly alkaline clay rock mainly containing montmorillonite, which is an example of the layered clay mineral of the present invention. In the present embodiment, high-purity purified bentonite with a montmorillonite content of a predetermined value or more is used for preparing the bentonite dispersion. Specifically, the purity of the high-purity purified bentonite is such that the montmorillonite content is 80% by weight or more, preferably 85% by weight or more, and most preferably 95% by weight or more.

[0041] To determine the purity of this bentonite, for example, the colorimetric determination method of methylene blue in accordance with JBAS-107-91 is used, that is, the sample is added to a sodium pyrophosphate solution and a methylene blue solution, and the solution is dropped onto filter paper to observe the presence or absence of the appearance of a halo. Then, the methylene blue adsorption amount of the bentonite with unknown purity is divided by the methylene blue adsorption amount of 100% by weight of montmorillonite content to obtain the purity. For example, when the methylene blue adsorption amount of the bentonite with unknown purity is 136 mmol / 100 g, and the methylene blue adsorption amount of 100% by weight of montmorillonite content is defined as 140 mmol / 100 g, the purity of the bentonite is calculated as (136 / 140)×100 = 97% by weight.

[0042] When producing fine powder of such high-purity purified bentonite, the crude bentonite obtained by crushing the ore is added to water and swollen and dispersed to obtain a crude liquid. This crude liquid is subjected to centrifugation treatment in multiple stages (for example, 3 stages) to obtain a purified liquid (impurities will settle), and the purified liquid is dried to obtain fine powder of high-purity purified bentonite.

[0043] The content of bentonite in the above-mentioned bentonite dispersion is set to be 4.5% by weight or more and 15% by weight or less. If the content of the fine powder of purified bentonite is less than 4.5% by weight, it may not be possible to ensure the desired gas barrier property (non-flammability). If it exceeds 15% by weight, there may be too much swelling montmorillonite, leading to deterioration of water resistance. The content of bentonite in the bentonite dispersion is set so that the amount of montmorillonite in the coating layer 30 is 3.3 g / m 2 or more.

[0044] In this embodiment, a relatively inexpensive bentonite fine powder containing montmorillonite particles with a relatively short length in the layer plane direction is used for the non-combustible paint. In this embodiment, by means of the high-pressure dispersion treatment described later, the montmorillonite particles can be exfoliated without shortening the length in the layer plane direction of the montmorillonite particles. Therefore, by using a relatively inexpensive bentonite fine powder and performing the high-pressure dispersion treatment described later, a dispersion liquid with a viscosity of 4000 mPa·s or more in which montmorillonite particles with an aspect ratio of 100 or more and 300 or less are dispersed is prepared and used for the non-combustible paint that forms the coating layer 30. Therefore, the coating layer 30 made of such a non-combustible paint composition contains montmorillonite particles with an aspect ratio of 100 or more and 300 or less, and they are stacked in several layers. The coating layer 30 exhibits gas barrier properties due to the maze effect because such montmorillonite particles are stacked.

[0045] Note that the above-mentioned "viscosity" refers to the viscosity measured by a B-type viscometer in accordance with JIS Z8803.

[0046] Also, the above-mentioned "aspect ratio" refers to the average value of the aspect ratios of 100 randomly selected montmorillonite particles in the dispersion liquid. Furthermore, the "dispersion liquid with a viscosity of 4000 mPa·s or more in which montmorillonite particles with an aspect ratio of 100 or more and 300 or less are dispersed" refers to a dispersion liquid in which montmorillonite particles have an aspect ratio of 100 or more and 300 or less when ideally dispersed (exfoliated to near the unit crystal), and the viscosity is 4000 mPa·s or more. The aspect ratio of the montmorillonite particles is obtained by drying the dispersion liquid and measuring the area and thickness of the layer plane of each montmorillonite particle with an AFM (Atomic Force Microscope). The diameter of the circle with an area corresponding to the measured area is taken as the length in the layer plane direction, and it is calculated from the length in the layer plane direction and the measured thickness.

[0047] An emulsion resin is a liquid in which particles of a synthetic resin are uniformly dispersed in water. As the synthetic resin of the emulsion resin, for example, an acrylic resin, a urethane resin, an epoxy resin, a vinyl chloride resin, a silicone resin, or a mixture arbitrarily selected from these is used. In particular, since an acrylic resin is excellent in film-forming properties, hardness, and glass permeability, it is preferable to include an acrylic resin.

[0048] The emulsion resin may be one in which particles (emulsions) are stabilized by an emulsifier, or may be a so-called soap-free type that is stabilized without using an emulsifier. The soap-free emulsion resin is an emulsion resin in which a surfactant used during emulsion polymerization is a reactive surfactant. Thereby, the coating film strength and water resistance can be improved.

[0049] The solid content ratio of the emulsion resin is desirably 3% by weight or more and 30% by weight or less. If it is less than 3% by weight, the adhesion to the building base material 10 is insufficient when there is no sealer layer 20 or when the sealer layer 20 is present, and sufficient strength cannot be obtained for the coating film. If it exceeds 30% by weight, the resin component in the coating film layer 30 increases, and the resin (coating film layer 30) itself becomes flammable.

[0050] -Method for manufacturing a non-combustible board- Next, a method for manufacturing a non-combustible board will be described. The method for manufacturing a non-combustible board includes a paint adjustment step of adjusting a non-combustible paint, a primer application step of applying a primer paint to a building base material to form a sealer layer 20, and a topcoat application step (painting step) of applying a topcoat paint (non-combustible paint) to the building base material to form a coating film layer 30.

[0051] [Paint adjustment step] The paint adjustment step includes a high-pressure dispersion treatment step of performing a high-pressure dispersion treatment on a bentonite suspension in which bentonite is mixed in a dispersion liquid to produce a dispersion liquid in which montmorillonite particles are dispersed, and a mixing step of mixing an emulsion resin into the dispersion liquid after the high-pressure dispersion treatment to adjust it to a non-combustible paint.

[0052] First, a high-pressure dispersion treatment step is performed. In the high-pressure dispersion treatment step, bentonite fine powder is mixed with water as a water-soluble solvent to prepare, for example, a suspension of bentonite with a content rate of 6%. The prepared bentonite suspension is introduced into a high-pressure dispersion treatment device. As the high-pressure dispersion treatment device, a high-pressure homogenizer, a mascolloidizer, a ball mill, etc. can be used. In the high-pressure dispersion treatment device, a high-pressure dispersion treatment is performed by applying pressure to the bentonite suspension and further ejecting it from a gap to apply a pressure of 100 MPa or more. At this time, the montmorillonite particles in the bentonite suspension collide with each other and apply a shearing force to each other, resulting in cleavage (separation between layers) in the montmorillonite particles.

[0053] In this embodiment, a high pressure of 100 MPa or more is applied by applying pressure to the bentonite suspension and then ejecting it from a gap. By applying such a high pressure at the time of ejection, the montmorillonite particles are easily cleaved until they become close to a unit crystal (one layer) in a short time. Therefore, the montmorillonite particles contained in the dispersion liquid after the high-pressure dispersion treatment become extremely thin without shortening the length in the layer plane direction, resulting in a high aspect ratio. As a result, the viscosity of the dispersion liquid after the high-pressure dispersion treatment becomes about 4000 mPa·s, which is dramatically higher than that in the case where the dispersion treatment is performed with a stirrer under the same conditions (2320 mPa·s). When the bentonite suspension is ejected from a gap, a high pressure of 100 MPa or more acts on the bentonite suspension. However, since the montmorillonite particles are difficult to crack in a wet state (the length in the layer plane direction is difficult to shorten), the aspect ratio does not decrease.

[0054] After the high-pressure dispersion treatment step, a mixing step is performed in which an emulsion resin is mixed with the prepared dispersion liquid to adjust it to a non-combustible paint. In this embodiment, an acrylic resin is used as the emulsion resin. The emulsion resin is mixed so that the weight ratio of the emulsion resin in the non-combustible paint is 13% by weight or more and 26% by weight or less. In this embodiment, the emulsion resin is mixed so that the weight ratio of the emulsion resin in the non-combustible paint is 20% by weight and the weight ratio of the dispersion liquid is 80% by weight.

[0055] Through the above steps, a non-combustible paint containing bentonite and emulsion resin as a non-combustible paint composition is prepared. In addition, as other additives for the non-combustible paint, auxiliary agents such as defoamers, dispersants, wetting agents, and fungicides may be added, and pigments may also be added depending on the application.

[0056] [Priming process] The priming process is a process of applying a primer paint (sealer paint) to the surface of the building substrate 10 and then drying it. Thereby, the sealer layer 20 is formed. As the application method of the primer paint, known methods such as a roll coater, a flow coater, and a spray can be adopted. The application amount of the primer paint is, for example, 10 g / m 2 to 100 g / m 2 or less is preferable. For drying, known methods such as a hot air dryer can be adopted.

[0057] [Topcoating process (painting process)] The topcoating process is a process of applying a topcoat paint (non-combustible paint) to the surface of the sealer layer 20 and then drying it. Thereby, the paint film layer 30 is formed. The topcoat paint is the non-combustible paint adjusted in the paint adjustment process. The application method of the topcoat paint is not particularly specified, and known methods such as a flow coater, a roll coater, and a spray can be adopted. Also, the application amount of the topcoat paint is, for example, 100 g / m 2 to 300 g / m 2 or less is preferable. The drying and curing method can also be carried out by known methods such as a hot air dryer.

[0058] [Non-combustibility test] To confirm that the non-combustible plate material with a paint film layer formed on the surface by applying the non-combustible paint according to the present invention is excellent in non-combustibility, test specimens T0 to T9 were prepared, and a heat generation test was conducted in accordance with JISA1316 (a test method for measuring the heat generation rate and smoke generation rate of building materials by a cone calorimeter), and the total heat generation amount 20 minutes after the start of heating was measured.

[0059] Test specimens T0 to T9 used a 12-mm volcanic glass multi-layer board as the building base material 10, and applied an undercoat paint at 80 g / m 2 to form a sealer layer 20, and after appropriate drying, 200 g / m of non-combustible paints P0 to P9 were applied on the sealer layer 20 2 to form a non-combustible coating film layer 30, and were appropriately dried and fixed.

[0060] All of the non-combustible paints P0 to P9 are a mixture of a dispersion liquid in which montmorillonite particles prepared by dispersing fine powder of high-purity purified bentonite in a 6% content bentonite suspension mixed with water and an emulsion resin in a weight ratio of 8 to 2. The non-combustible paints P0 to P9 differ in the combination of the type of fine powder of bentonite and the dispersion treatment method.

[0061] Specifically, for the non-combustible paints P0 to P5, fine powders of relatively inexpensive bentonite containing montmorillonite particles with a relatively short length in the layer plane direction and thus a relatively small aspect ratio (100 - 300 in an ideal dispersion state) are used. For the non-combustible paints P6 to P9, fine powders of relatively expensive bentonite containing montmorillonite particles with a relatively long length in the layer plane direction and thus a relatively large aspect ratio (300 - 500 in an ideal dispersion state) are used. Also, the non-combustible paints P0 to P4, P6 to P8 contain a dispersion liquid obtained by subjecting a bentonite suspension to a high-pressure dispersion treatment. On the other hand, the non-combustible paints P5, P9 are those in which the bentonite suspension is stirred with a well-known stirring device without subjecting it to a high-pressure dispersion treatment to disperse the montmorillonite particles. Furthermore, the non-combustible paints P0 to P4, P6 to P8 have different pressure conditions for the high-pressure dispersion treatment. The non-combustible paint P0 is one in which a pressure of 50 MPa is applied to the bentonite suspension in the high-pressure dispersion treatment, the non-combustible paint P1 is one in which a pressure of 100 MPa is applied to the bentonite suspension in the high-pressure dispersion treatment, the non-combustible paints P2, P6 are those in which a pressure of 160 MPa is applied to the bentonite suspension in the high-pressure dispersion treatment, the non-combustible paints P3, P7 are those in which a pressure of 200 MPa is applied to the bentonite suspension in the high-pressure dispersion treatment, and the non-combustible paints P4, P8 are those in which a pressure of 245 MPa is applied to the bentonite suspension in the high-pressure dispersion treatment.

[0062] Due to the differences in the combination of the types of the above-mentioned fine powders of bentonite and the dispersion treatment methods, in the non-combustible paints P0 to P9, the combinations of the aspect ratio (average value) of the contained montmorillonite particles and the viscosity of the dispersion liquid are different. Note that the measurement of the viscosity of the dispersion liquid used for the non-combustible paints P0 to P9 shown below was performed after leaving it to stand overnight after the dispersion treatment.

[0063] In the non-combustible paints P1 to P4 that were subjected to high-pressure dispersion treatment using relatively inexpensive fine powders of bentonite, the montmorillonite particles contained were sufficiently exfoliated without the length in the layer plane direction being shortened, resulting in a high aspect ratio, and the relative amount of montmorillonite particles contained in the dispersion increased. Therefore, as shown in Fig. 2, the viscosities of the dispersions were relatively high at 4330 mPa·s, 4230 mPa·s, 4300 mPa·s, and 4160 mPa·s, respectively.

[0064] On the other hand, in the non-combustible paint P0 that was subjected to high-pressure dispersion treatment using relatively inexpensive fine powders of bentonite but with an operating pressure of less than 100 MPa (50 MPa), the contained montmorillonite particles were not sufficiently exfoliated, so the relative amount of montmorillonite particles contained in the dispersion was less than that in the non-combustible paints P1 to P4. As shown in Fig. 2, the viscosity of the dispersion was relatively low at 2770 mPa·s.

[0065] Also, in the non-combustible paint P5 that was subjected to dispersion treatment by stirring in the same manner as in the conventional method using relatively inexpensive fine powders of bentonite, the contained montmorillonite particles were not sufficiently exfoliated, so the relative amount of montmorillonite particles contained in the dispersion was less than that in the non-combustible paints P1 to P4. As shown in Fig. 2, the viscosity of the dispersion was 2320 mPa·s.

[0066] In the non-combustible paints P6 to P9 that used relatively expensive fine powders of bentonite, since the aspect ratios of the montmorillonite particles already contained before the dispersion treatment were relatively high, regardless of the dispersion treatment method, the aspect ratios of the contained montmorillonite particles were high. As shown in Fig. 2, the viscosities of the dispersions were relatively high at 4100 mPa·s, 4200 mPa·s, 4000 mPa·s, and 5900 mPa·s, respectively.

[0067] As described above, the non-combustible paints P1 to P4 are non-combustible paints according to the present invention in which a dispersion liquid having a viscosity of 4000 mPa·s or more in which particles of a layered clay mineral (montmorillonite) having an aspect ratio of 100 or more and 300 or less are dispersed in an ideal dispersion state and an emulsion resin are mixed. The test pieces T1 to T4 coated with the non-combustible paints P1 to P4 are non-combustible plates according to the present invention.

[0068] For the test pieces T1 to T9 on which the coating film layers 30 with the non-combustible paints P1 to P9 as described above were formed, when a heat generation test was conducted using a cone calorimeter, the total heat generation amount from the start of heating for 20 minutes was, as shown in FIG. 2, 3.4 MJ / m for the test piece T1 2 , 1.5 MJ / m for the test piece T2 2 , 0.8 MJ / m for the test piece T3 2 , 1.9 MJ / m for the test piece T4 2 , 4.6 MJ / m for the test piece T5 2 , 1.5 MJ / m for the test piece T6 2 , 1.0 MJ / m for the test piece T7 2 , 1.0 MJ / m for the test piece T8 2 , 1.4 MJ / m for the test piece T9 2 .

[0069] That is, in the test pieces T1 to T4 in which the coating film layers 30 were formed with the non-combustible paints P1 to P4 which are non-combustible paints according to the present invention, the total heat generation amount from the start of heating for 20 minutes by the heat generation test was 3.4 MJ / m 2 or less, and it was 1.2 MJ / m 2 or more lower than the result of the same test of the test piece T5 in which the coating film layer 30 was formed with the conventional non-combustible paint P5 in which the dispersion treatment method was stirring using fine powder of inexpensive bentonite (4.6 MJ / m 2 ). That is, it was confirmed that when the non-combustible paint according to the present invention is used, a coating film layer 30 excellent in gas barrier properties and non-combustibility can be formed as compared with the case of using the conventional non-combustible paint P5. Further, the total heat generation amounts of the test pieces T1 to T4 are the performance requirement contents (total heat generation amount 8.0 MJ / m 2 or less) required by the standards of the Building Standards Law as a flame retardant material, a quasi-non-combustible material, and a non-combustible material, and are 4.6 MJ / m 2It has become lower than the above. Therefore, by using the non-combustible paint according to the present invention, when manufacturing a non-combustible plate material, the range of variations in the surface finishing can be expanded. Specifically, a combustible finishing (such as a decorative sheet, veneer, etc.) may be applied to the surface to enhance the design property. However, if the total heat release amount of the portion other than the decorative layer is low, for example, it becomes possible to use a veneer of broad-leaved tree with a high specific gravity and a large organic component content, or to apply paint to the veneer surface.

[0070] In addition, in addition to the above test, the inventors of the present application also conducted a heat generation test on a test piece T2' in which a veneer (oak material) with a thickness of 0.2 mm was adhered to the surface of the test piece T2 and coated with 80 g / m2 of urethane paint. As a result, the total heat release amount from the start of heating for 20 minutes was 6.1 MJ / m 2 It was. The total heat release amount of the test piece T2 is 1.5 MJ / m 2 Therefore, the heat release amount of the decorative layer portion is 4.6 MJ / m 2 From this result, when the same finishing as that of the test piece T2' was applied to the surfaces of the test piece T1 and the test piece T5 to produce the test piece T1' and the test piece T5', the total heat release amount of the test piece T1' was the heat release amount of the test piece T1 portion 3.4 MJ / m 2 And the heat release amount of the decorative layer portion 4.6 MJ / m 2 And it became 8.0 MJ / m 2 And it satisfies the above performance requirement content (total heat release amount 8.0 MJ / m 2 or less). However, the total heat release amount of the test piece T5' is the heat release amount of the test piece T5 portion 4.6 MJ / m 2 And the heat release amount of the decorative layer portion 4.6 MJ / m 2 And it became 9.2 MJ / m 2 And it does not satisfy the above performance requirement content (total heat release amount 8.0 MJ / m 2 or less). That is, the same finishing as that of the test piece T2' cannot be adopted for the test piece T5 using the conventional non-combustible paint, and the range of variations in the surface finishing becomes narrow.

[0071] In addition, in test specimens T6 to T9 using non-combustible paints P6 to P9 that use fine powders of expensive bentonite containing montmorillonite particles with a relatively long length in the plane direction and thus a relatively large aspect ratio, the total heat generation amount from the start of heating in the heat generation test for 20 minutes was 1.5 MJ / m 2 The following results were obtained, and it was confirmed that all of them were excellent in non-combustibility. Among the test specimens T1 to T4, which are non-combustible plate materials according to the present invention, particularly the results of the heat generation test of test specimens T2 to T4 (the total heat generation amount from the start of heating for 20 minutes was 1.9 MJ / m 2 The following) are comparable to the results of the heat generation test of test specimens T6 to T9 (the total heat generation amount from the start of heating for 20 minutes was 1.5 MJ / m 2 The following). Therefore, it was confirmed that, like the non-combustible paint according to the present invention, even when using fine powders of inexpensive bentonite, a coating film layer excellent in gas barrier properties and non-combustibility can be formed, and a non-combustible plate material excellent in non-combustibility can be provided at low cost.

[0072] - Effects of the Embodiment - As described above, in the present embodiment, the non-combustible paint for forming the coating film layer 30 contains a dispersion liquid having a viscosity of 4000 mPa·s or more in which montmorillonite particles (particles of a layered clay mineral) having an aspect ratio of 100 or more and 300 or less are dispersed.

[0073] As described above, the inventors of the present application conducted a heat generation test using a cone calorimeter on the non-combustible plate material 1 on which the coating film layer 30 was formed by the above non-combustible paint, and measured the total heat generation amount from the start of heating for 20 minutes. As a result, it was 3.4 MJ / m 2 The following. Compared with the case of using a conventional non-combustible paint containing a dispersion liquid having a viscosity of less than 4000 mPa·s (for example, 2320 mPa·s) in which montmorillonite particles similar to the above non-combustible paint are dispersed by stirring (total heat generation amount: 4.6 MJ / m 2 ), it was confirmed that a coating film layer excellent in gas barrier properties and non-combustibility can be formed. In addition, when a conventional non-combustible paint (for example, non-combustible paint P5) is used and a decorative process is applied to the surface, the performance requirements required by the Building Standards Law as a flame-retardant material, a quasi-non-combustible material, and a non-combustible material (total heat generation amount: 8.0 MJ / m 2It is confirmed that it does not satisfy the following) or the range of variations in the surface finishing is narrowed in order to satisfy the performance requirements.

[0074] As described above, according to the non-combustible paint of the present embodiment, the coating film layer 30 excellent in gas barrier properties and non-combustibility can be formed. Further, according to the non-combustible paint of the present embodiment, since the gas barrier properties of the coating film layer 30 formed without increasing the content of montmorillonite can be improved, it does not lead to a decrease in the coating film strength or deterioration of water resistance. In addition, fine powder of relatively inexpensive bentonite containing montmorillonite particles having an aspect ratio of 100 or more and 300 or less can be used. Therefore, according to the non-combustible paint of the present embodiment, the coating film layer 30 excellent in gas barrier properties and non-combustibility can be inexpensively formed without causing a decrease in the coating film strength or deterioration of water resistance. Further, when the non-combustible paint of the present embodiment is used, in manufacturing the non-combustible plate material 1, the range of variations in the surface finishing is expanded, and for example, it becomes possible to use a veneer of a hardwood having a high specific gravity and a large organic content, or to apply a coating to the veneer surface.

[0075] Further, in the method for preparing the non-combustible paint of the present embodiment, a high-pressure dispersion treatment is performed by applying pressure with a high-pressure dispersion device to a bentonite suspension in which fine powder of bentonite containing montmorillonite particles (particles of layered clay mineral) is mixed in a water-soluble solvent and ejecting it from a gap, so that a high pressure of 100 MPa or more is applied to the bentonite suspension at the time of ejection. According to such a high-pressure dispersion treatment, the montmorillonite particles in the bentonite suspension collide with each other and apply a shearing force to each other, causing cleavage (separation between layers) in the montmorillonite particles. However, in the present embodiment, by applying a high pressure of 100 MPa or more to the bentonite suspension at the time of ejection of the bentonite suspension, the montmorillonite particles are easily cleaved until they become close to a unit crystal (one layer) in a short time. Therefore, the montmorillonite particles contained in the dispersion liquid after the high-pressure dispersion treatment become extremely thin and have a high aspect ratio. When the montmorillonite particles are cleaved until they become close to a unit crystal (one layer), the relative amount of the montmorillonite particles contained in the dispersion liquid increases, so that the viscosity of the dispersion liquid increases and the montmorillonite particles are likely to overlap in layers to form a multilayer structure. Therefore, the gas barrier property of the coating film layer 30 formed by the non-combustible paint is improved and the non-combustibility is enhanced. Thus, according to the method for preparing the non-combustible paint of the present embodiment, a non-combustible paint containing a dispersion liquid having a viscosity of 4000 mPa·s or more in which montmorillonite particles having an aspect ratio of 100 or more and 300 or less are dispersed can be easily prepared. Therefore, a coating film layer 30 excellent in gas barrier property and non-combustibility can be formed at low cost without causing a decrease in coating film strength or deterioration of water resistance.

[0076] Further, in the present embodiment, the non-combustible plate material 1 forms a coating film layer 30 containing montmorillonite particles (particles of layered clay mineral) having an aspect ratio of 100 or more and 300 or less on one or both sides of the building base material 10, so that the total calorific value in the heat generation test for 20 minutes is 3.4 MJ / m 2 It is configured as follows. This total calorific value is the result (4.6 MJ / m2 ) is lower by 1.2 MJ / m 2 than the above, and the non-combustible board material 1 is excellent in non-combustibility. Also, in the non-combustible board material 1 of the present embodiment, the coating layer 30 contains montmorillonite particles (particles of layered clay minerals) having an aspect ratio of 100 or more and 300 or less. Such a coating layer 30 can be formed relatively inexpensively using fine powder of relatively inexpensive bentonite. Therefore, according to the present embodiment, a non-combustible board material 1 excellent in non-combustibility can be provided at low cost. Also, when the non-combustible board material 1 of the present embodiment is used, the total calorific value in the heat generation test is low, and even if a combustible decorative process is applied to the surface, the performance requirements required by the Building Standards Law as a flame-retardant material, semi-non-combustible material, and non-combustible material (total calorific value 8.0 MJ / m 2 or less) are easily satisfied, so that various decorative processes can be applied to the surface, and a board material excellent not only in non-combustibility but also in design can be provided.

[0077] Also, in the present embodiment, a paint adjustment step of adjusting the non-combustible paint by the above-described method for adjusting the non-combustible paint, and applying the adjusted non-combustible paint to one side or both sides of the building base material 10 at 100 g / m 2 or more and 300 g / m 2 or less to form the coating layer 30. By such a manufacturing method, the coating layer 30 excellent in gas barrier properties and non-combustibility can be formed on one side or both sides of the building base material 10 at low cost without causing a decrease in coating strength or deterioration of water resistance. Therefore, according to the manufacturing method of the non-combustible board material 1 of the present embodiment, a non-combustible board material 1 excellent in non-combustibility can be provided at low cost.

[0078] 《Other Embodiments》 In the above embodiment, the non-combustible board 1 in which the coating film layer 30 made of the non-combustible paint composition is formed by applying the non-combustible paint to the surface (one side) of the building base material 10 has been described. However, a similar coating film layer 30 may be formed on the back surface (one side) of the building base material 10. Further, in addition to the surface of the building base material 10, a similar coating film layer 30 may be formed on both the front and back surfaces (both sides) to constitute the non-combustible board 1, and the non-combustibility of the non-combustible board 1 can be further improved.

[0079] In addition, since the coating film layer 30 formed by the non-combustible paint according to the present invention is excellent in gas barrier properties as described above, it can also be used as an alternative to the moisture-proof sheet as a water vapor barrier for suppressing warping of the building base material 10.

Industrial Applicability

[0080] The present invention is useful for non-combustible paints, methods for adjusting non-combustible paints, non-combustible boards, and methods for manufacturing non-combustible boards.

Explanation of Reference Numerals

[0081] 1 Non-combustible board 10 Building base material 20 Sealer layer 30 Coating film layer

Claims

1. A non-combustible paint for forming a coating film layer, wherein a dispersion having a viscosity of 4000 mPa·s or more in which particles of a layered clay mineral having an aspect ratio of 100 or more and 300 or less are dispersed is mixed with an emulsion resin. A non-combustible paint characterized by the above.

2. In the non-combustible paint of Claim 1, the layered clay mineral is montmorillonite. A non-combustible paint characterized by the above.

3. A method for preparing a non-combustible paint for forming a coating film layer, by applying pressure to a suspension in which particles of a layered clay mineral are mixed in a water-soluble solvent with a high-pressure dispersion device and ejecting it from a gap, so that a pressure of 100 MPa or more is applied to the suspension at the time of ejection to disperse the particles of the layered clay mineral having an aspect ratio of 100 or more and 300 or less to prepare a dispersion having a viscosity of 4000 mPa·s or more, a high-pressure dispersion treatment step, and a mixing step of mixing an emulsion resin with the dispersion prepared in the high-pressure dispersion treatment step. A method for preparing a non-combustible paint characterized by the above.

4. In the method for preparing a non-combustible paint according to Claim 3, the layered clay mineral is montmorillonite, and in the high-pressure dispersion treatment step, a fine powder of bentonite is mixed with the dispersion to prepare the suspension. A method for preparing a non-combustible paint characterized by the above.

5. A non-combustible plate material having a coating film layer made of a non-combustible paint composition formed on one or both sides of a building base material, wherein the coating film layer contains particles of a layered clay mineral having an aspect ratio of 100 or more and 300 or less. The total heat generation amount in the heat generation test of the above non-combustible sheet material is 3.4 MJ / m for 20 minutes ２ and is as follows A non-combustible plate material characterized by the above.

6. The non-combustible plate material according to Claim 5, wherein the layered clay mineral is montmorillonite. A non-combustible plate material characterized by the above.

7. A method for manufacturing a non-combustible plate material having a coating film layer made of a non-combustible paint composition formed on one or both sides of a building base material, a paint adjustment step of adjusting a non-combustible paint containing the non-combustible paint composition by the adjustment method according to Claim 3 or 4. Apply the non-combustible paint adjusted in the above paint adjustment process to one or both sides of the above building substrate at 100 g / m ２ or more and 300 g / m ２ or less to form the above coating film layer, comprising a painting process A method for manufacturing a non-combustible plate material characterized by the above.

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