JPH0957187A - Coating method for inorganic building material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the sticking and integration of inorganic hydraulic plates which are coated and piled for curing and the deposition of efflorescence powder from the surface of the plate and to provide a plate product having a good adhesion between the cured plate and an overcoating film. SOLUTION: The surface of an unhardened inorganic hydraulic plate is coated with a water base under coating paint composed of an acrylic resin and a filler having an average particle size of 15-100μm. The plates are piled, cured in an autoclave, and then hardened.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for coating an inorganic building material with high production efficiency, which is applied to a building material such as a plate roof tile or a plate outer wall board.

[0002]

2. Description of the Related Art In plate-like inorganic building materials such as roof tiles and outer wall materials, an inorganic hydraulic material is usually formed into a plate shape (hereinafter referred to as "raw raw board") and cured and hardened. When these are lined up in a plane and cured, a huge floor area is required, so that the raw plates are usually stacked and cured.

By the way, when uncured raw plates are stacked and cured in an autoclave, the obtained plate materials adhere to each other and are integrated, or efflorescence powder is deposited on the surface of the plate material to form a coating film of the topcoat paint. Since the adhesion failure occurs, the following method has been conventionally adopted as a method for preventing it.

(A) A method in which, after stacking raw raw plates, a pre-treatment time until curing is long and curing is performed.

(B) A method of curing a stacked raw original plate by inserting a plastic film such as polyester between the raw original plates.

(C) A method in which a synthetic resin coating material is applied to the surface of the raw raw plate and then the stacked raw raw plates are cured.

(D) A method in which a synthetic resin coating material having releasability is applied to the surface of the raw raw plate and then the stacked raw raw plates are cured.

(E) A method of vertically stacking raw raw plates and curing them in a state where basically no load is applied.

[0009]

However, in the method (a), the production time is long, the production efficiency is very poor, and since efflorescence powder is generated on the surface after curing, it is removed. If the coating is not applied, a coating film defect occurs, and there is a problem that an extra process for removing efflorescence powder is required.

In the method (b), the film is melted by heating during curing, which causes stains and the like, resulting in a bad appearance, and it takes time to insert the film, and the cost is high. There was a problem that became.

Further, in the above method (c), since the organic binder is used when it is cured in the autoclave, the coating film is likely to be softened. Therefore, when the plate materials are adhered to each other or integrated, the coating film is peeled off. However, there is a problem in that it is apt to be partially lost and the function as an undercoating paint is not sufficiently exhibited.

Further, in order to prevent the adhesion and integration phenomenon between the plate materials, a method of preventing the integration by minimizing the coating amount has been implemented, but there is a drawback that the adhesion of efflorescence powder becomes large.

Further, in the method (d), since a synthetic resin coating material having releasability is applied, there is a problem that when the top coating material is applied after curing, the interlayer adhesion to the top coating film is deteriorated. there were.

Further, in the above method (e), since the plate material is autoclave-cured in the vertical direction, the efflorescence component easily flows down to the plate material, but the raw raw plate traveling in the horizontal direction on the conveyor is in the vertical direction. There is a problem in that a complicated device is required to put them upside down and the raw plate is easily deformed.

In view of the above situation, the present inventors have made diligent studies to solve the above-mentioned problems, and as a result, prevent adhesion and integration between plate materials, and prevent precipitation of efflorescence powder, and The present invention has been accomplished by finding a coating material having a function as an undercoat coating film having good adhesion to an overcoat coating film.

[0016]

The present invention provides an acrylic resin and an average particle size of 1 on the uncured surface of an inorganic hydraulic board.
The present invention relates to a method for coating an inorganic building material in which a water-based undercoat paint containing a filler of 5 to 100 μm as an essential component is applied, and then the obtained coated plate materials are stacked, followed by autoclave curing and curing.

Hereinafter, the present invention will be described in detail.

In the present invention, as the inorganic hydraulic plate material, various cements, substances such as calcium silicate, gypsum, lime and the like which are hardened by a hydration reaction are fine aggregates, lightweight aggregates,
It is a material formed by mixing a reinforcing fiber and the like into a plate shape, and examples thereof include those conventionally used for ordinary building materials.

The water-based undercoat paint used in the present invention comprises an acrylic resin and a filler having an average particle diameter of 15 to 100 μm as essential components, and if necessary, various pigments, various additives, modifiers, a small amount of organic solvent, and further. It is a mixture of water for dilution.

The acrylic resin has 1 carbon atom of acrylic acid.
~ 8 alkyl ester monomers, copolymers of methacrylic acid alkyl ester monomers having 1 to 8 carbon atoms or monomers copolymerizable with these monomers, such as (meth) acrylic acid, itaconic acid, (meth) acrylic acid 2-
Hydroxyethyl, glycidyl (meth) acrylate,
Functional monomers such as (meth) acrylamide and N-methylol (meth) acrylamide, or styrene, vinyltoluene, (meth) acrylonitrile, vinyl chloride,
An emulsion resin obtained by polymerizing according to a conventional method in the presence of an emulsifier by appropriately combining monomers such as butadiene is suitable.

The molecular weight of these acrylic emulsion resins is about 50,000 to 300,000, preferably 10
It is advantageously between 20,000 and 200,000.

Glass transition temperature of acrylic resin (hereinafter, T
It is advantageous that the value of g) is 20 ° C. or higher, preferably 40 ° C. or higher because blocking (integral adhesion between stacked plate materials) is unlikely to occur. The upper limit of Tg is about 130 ° C.

The acrylic resin may be a normal dry type or a baking type, and a self-crosslinking type resin in which zinc oxide, a metal complex salt, a hydrazide compound or the like is used in combination is also usable.

The filler having an average particle diameter of 15 to 100 μm is spherical or indefinite, and specific examples thereof include urethane type, melamine type, phenol type, polyamide type and polyimide type melting points of 120 ° C. The above plastic beads or mineral particles such as kaolin, talc, mica, calcium carbonate, silica stone powder, silica sand, alumina powder, barium sulfate, quartz powder, graphite, glass powder, glass beads, ceramic powder and various ceramic particles Examples of the powder include metallic particles such as iron, nickel, aluminum and stainless.

These particulate powders have an average particle size of 15 to 100 μm, which protrudes to the surface of the coating film and reduces the contact area between the plate materials to effectively prevent integration, and is preferably 2
It is 0 to 80 μm. If the average particle size is smaller than 15 μm, the effect of preventing integration is small, and the average particle size is 10
If it is larger than 0 μm, there is no coating machine that can be applied stably,
Also, it becomes difficult to control the coating amount. The blending amount of the present particulate filler is 10 to 150 parts by weight, preferably 30 to 100 parts by weight, based on 100 parts by weight of the solid content of the acrylic emulsion. If the blending amount of the filler is less than 10 parts by weight, the effect of preventing unification is small, and if the blending amount of the filler is more than 150 parts by weight, it becomes difficult to select a coating machine and control the coating.
In addition, the adhesion with the material may be adversely affected.

As the pigments to be blended as necessary in addition to the above-mentioned essential components, various pigments may be general inorganic pigments or organic pigments, but from the viewpoint of heat resistance, hot water resistance, alkali resistance, etc. A pigment is desirable.

Specific examples thereof include coloring pigments such as titanium oxide, iron oxide and carbon black, and extender pigments such as calcium carbonate, talc and barium sulfate, but the present invention is not limited thereto. .

Examples of various additives include various dispersants, thickeners, defoamers, antiseptics, antifungal agents, film forming aids and the like.

Further, water as a diluent is appropriately added so that the solid content of the undercoat paint is 3 to 65% by weight, preferably 5 to 40% by weight.

Next, the method of coating the inorganic building material of the present invention will be described.

The inorganic hydraulic material is formed into a plate by a usual method such as an extrusion molding method, a press molding method, an integral molding method, a dry molding method, a casting molding method, and a papermaking method. Then, if necessary, heat curing (eg, 40 to 100 ° C. for 4 hours to 2
Primary curing by means of (heating for 0 hours).

The undercoating paint can be applied to a plate immediately after molding or a plate after primary curing. The coating method is air spray, airless spray, shower coat, flow coat, roll coat or the like. Apply by. The wet coating amount is 10 to 150 g / m ² ,
It is suitable to apply it so that the amount is preferably 20 to 80 g / m ² . Then, the coated raw plates are stacked. It should be noted that when stacking the coated raw plates, when the undercoat paint is applied and the undercoat film is in a wet state (preferably within 2 minutes after application), or when the stack is not damaged when stacked (half ) When cured (eg 1
Dry at 30 ° C. for about 3 minutes or more).

When the raw coating plates are piled up when they are hardened to such an extent that the coating films are damaged when they are stacked, the coating film adheres to the other adjacent coating raw plate, and as a result, the plate materials are easily integrated. It is not preferable.

Next, the coating raw plate which has not been subjected to primary curing is subjected to primary curing and then autoclave curing. After primary curing, the undercoat coated plate is autoclave cured (condition 160 ° ~ 1
The coated raw plate is cured at 85 ° C. for 6 hours to 14 hours.

The cured inorganic hydraulic board material having the undercoating film thus obtained is commercialized by applying an intermediate coating material, if necessary, and then applying an overcoating material according to a usual method. . The coating material is not particularly limited, but water-based coating materials such as an intermediate coating material and a top coating material, usually an acrylic resin emulsion coating material, are appropriately used, but the specific gravity of the base material is relatively small, and the roof tiles and other harsh use conditions In the application below, a solvent-based sealer such as an epoxy resin-based solution or an isocyanate prepolymer solution, which relatively easily penetrates into the substrate, may be used as the intermediate coating composition.

[0036]

According to the method of the present invention, since the specific water-based undercoat paint is applied to the surface of the uncured inorganic hydraulic board,
Even when the coated plate materials are stacked and cured by curing, the plate materials can be prevented from adhering to each other and being integrated, and the coating film of the water-based undercoat paint is formed on the plate material surface as it is. It is possible to obtain a plate material product which prevents the precipitation of efflorescence powder from the above and also has good adhesion to the plate material and the top coating film, and therefore has high production efficiency and excellent durability without peeling of the coating film.

[0037]

EXAMPLES The present invention will now be described in more detail by way of examples. In the examples, "parts" and "%" are shown by weight. <Production method of raw plate> Raw plate A Portland cement: 60 parts, silica sand: 50 parts, pulp fiber: 5 parts, sepiolite: 3 parts, carbon black:
A composition consisting of 1 part and 120 parts of water was formed into a plate by a papermaking method, and then press-molded to obtain a raw raw plate.

Raw Raw Plate B Portland cement: 36 parts, silica sand: 58 parts, fly ash: 4 parts, polypropylene fiber: 1 part, methyl cellulose: 1 part, water: 67 parts I got a master plate. <Primary curing condition> Condition (a) 40 ° C. for 8 hours Condition (b) 60 ° C. for 6 hours <Undercoating paints a to d / intermediate coating i to iii · Topcoating I to I
The composition of I> is shown in [Table 1]. (Example 1) An aluminum plate is appropriately inserted and stacked on a raw raw plate A, and primary curing [condition (a)] is performed. This plate material 1
Each sheet was conveyed onto a conveyor and the undercoat paint a was applied by a roll coater so that the coating amount was 45 g / m ² (wet). Then, after drying at 140 ° C. for 3 minutes, a coated plate material was loaded, and autoclave cured (heated to 180 ° C. for 2 hours and cured at the same temperature for 10 hours) to cure. Next, the top coating material 1 is applied by airless spraying at a coating amount of 120 g /
m ² (wet) was applied and dried at 110 ° C. for 13 minutes to cure the top coating film. Tests were conducted on the adhesion state of efflorescence powder after autoclave curing, blocking resistance of plate materials (prevention of integration), adhesion of coating film after top coating, and freeze-thaw property, and the results are shown in [Table 2]. . (Example 2) In Example 1, an intermediate coating material i was applied to the plate after curing in an autoclave by an airless spray, and the coating amount was 45.
Apply to g / m ² (wet), 130 ℃ × 5
The coating was performed in the same manner as in Example 1 except that the coating was dried for a minute. (Example 3) In Example 1, an intermediate coating composition ii was applied to a plate after curing in an autoclave with a roll coater to a coating amount of 20 g.
/ M ² (wet) and applied in the same manner as in Example 1 except for drying at 120 ° C. for 3 minutes. (Example 4) Coating was carried out in the same manner as in Example 3 except that the undercoat paint was changed to b. (Example 5) The undercoat paint c was applied to the raw raw plate B by an airless spray so that the application amount was 70 g / m ² (wet). Then, it was inserted into a frame pallet and subjected to primary curing (condition B). Then, the primary cured plate was taken out from the frame pallet and loaded, and autoclaved, heated to 160 ° C. for 2 hours, and cured at the same temperature for 8 hours) to cure. Next, the top coating composition II was applied by airless spraying at a coating amount of 110 g / m ² (w
Et) and dried at 120 ° C. for 10 minutes to cure the top coating film. (Example 6) An intermediate coating composition iii was applied to a plate after curing in the autoclave of Example 5 by airless spraying at 45 g / m ² (we
The coating was performed in the same manner as in Example 5 except that the coating was performed so as to be t) and the coating was dried at 130 ° C. for 5 minutes. (Comparative Example 1) Coating was carried out in the same manner as in Example 1 except that the undercoat paint d was used. (Comparative Example 2) In the same manner as in Example 1, except that the undercoating paint was not applied after the primary curing, the plate materials were loaded in the same manner, and the autoclave curing was performed to cure the plate materials. Next, the undercoat paint a is applied with an airless spray to a coating amount of 45 g / m ² (wet), dried at 90 ° C. for 5 minutes, and the topcoat paint I is further applied with an airless spray to a coating amount of 120 g.
Apply to g / m ² (wet), 110 ℃ × 1
It was dried for 3 minutes. (Comparative Example 3) In Example 5, a plate material was loaded in the same manner as in Example 5 except that the undercoat was not coated, and the plate material was cured by autoclaving to cure the plate material. The autoclave cured plate was cured. Next, the undercoat paint c is applied with an airless spray so that the coating amount is 70 g / m ² (wet), dried at 90 ° C. for 7 minutes, and further overcoated therewith.
II was applied at a coating amount of 110 g / m ² (wet) and dried at 110 ° C. for 10 minutes to cure the top coating film.

[0039]

[Table 1] Note 1) Acrylic emulsion Styrene / methyl methacrylate / butyl acrylate = 3
Solid content of 4/35/31 copolymer (Tg 48 ° C.) 41
% Emulsion, pH 8.0 Note 2) Styrene / methyl methacrylate / butyl acrylate = 15/55/30 copolymer (Tg 50 ° C.) solid content 48% emulsion, pH 9.5 Note 3) Epoxy resin aqueous Emulsion (Evolution E
A-7: Kanebo USC Product: Evaporation residue 6
1.5 ± 2.5%) / modified aliphatic polyamine resin aqueous emulsion (Eporjon EB-1; Kanebo UNC Co., Ltd. product name: evaporation residue 40 ± 2.5%) = 50/5
Mixture of 0 Note 4) Sumidule N75 (trade name of Bayer Urethane Co .; solid content 75 ± 1%, NCO content 16 ± 17%) Note 5) Epoxy resin (Epicoat 828; Shell Chemical Co., Ltd. trade name: epoxy equivalent 184 to 194) / curing agent (Epicure H2; product name of Shell Chemical Co., Ltd.) = 66/34 mixture 6) Silica powder: average particle diameter 24.1 μm (1.0 to 6)
7) Alumina powder: average particle diameter 27.6 μm (9.0-9.0)
(Distributed at 66.7 μm) Note 8) Acrylonitrile beads: average particle diameter 26 μm
(Distributed at 0.0 to 60.0 μm) Decomposes while melting at a melting point of 250 ° C Note 9) Precipitable barium sulfate: average particle size 0.6 to 1.0
μm Note 10) Kaolin: Average particle size 4.0 ± 0.4 μm

[0040]

[Table 2]

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location C09D 133/06 PFX C09D 133/06 PFX

Claims (6)

[Claims] 1. An acrylic resin and an average particle size of from 15 to 15 are formed on the uncured surface of an inorganic hydraulic plate material formed into a plate shape.
A method for coating an inorganic building material in which a water-based undercoat paint having a 100 μm filler as an essential component is applied, and then the obtained coated plate materials are stacked, followed by autoclaving and curing. 2. The method for coating an inorganic building material according to claim 1, wherein the glass transition temperature of the acrylic resin of the water-based undercoat paint is 20 ° C. or higher. 3. The method for coating an inorganic building material according to claim 1, wherein a finish coating is applied with a water-based or solvent-based top coating composition. 4. The method for coating an inorganic building material according to claim 1, wherein the uncured inorganic hydraulic plate material is subjected to primary curing after molding or before the autoclave curing step. 5. The method for coating an inorganic building material according to claim 4, wherein the primary curing is heating curing. 6. The method of coating an inorganic building material according to claim 1, wherein the amount of the filler is 10 to 150 parts by weight with respect to 100 parts by weight of the resin.