JP2900850B2 - Painting method for inorganic building materials - Google Patents

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 inorganic building materials with high production efficiency, which is applied to building materials such as plate roof tiles and plate outer wall plates.

[0002]

2. Description of the Related Art In general, plate-like inorganic building materials such as roof tiles and outer wall materials are formed by shaping an inorganic hydraulic material into a plate shape (hereinafter referred to as a raw plate) and curing. When these are arranged in a plane and cured, an enormous floor area is required. Therefore, usually, raw plates are stacked and cured.

When uncured raw plates are stacked and autoclaved, the resulting plate materials adhere to each other and are integrated, or efflorescence powder precipitates on the surface of the plate material to form a coating film of a top coat. Since the poor adhesion occurs, the following method has been conventionally employed as a method for preventing the poor adhesion.

[0004] (a) A method in which after pre-stacking raw plates, a long pre-setting time is required until curing.

(B) A method in which a plastic film such as polyester is inserted between raw sheets to cure the stacked raw sheets.

(C) A method of applying a synthetic resin paint to the surface of a raw plate and curing the stacked raw plates.

(D) A method of applying a releasable synthetic resin-based paint to the surface of a raw plate and curing the stacked raw plates.

(E) A method in which raw plates are erected in the vertical direction and cured under a state where a load is not basically applied.

[0009]

However, in the method (a), the production time is long, the production efficiency is very poor, and efflorescence powder is generated on the surface after curing. If the coating is not performed, a coating film defect occurs, and there is a problem that an extra eflorescence powder removal treatment step is required.

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

In the above method (c), when cured in an autoclave, the coating is easily softened because an organic binder is used. However, there is a problem that often occurs, and that the function as an undercoat paint is not sufficiently exhibited.

In order to prevent this phenomenon, a method of minimizing the amount of coating to prevent the integration has been practiced. However, there is a disadvantage that the adhesion of efflorescent powder becomes large.

In the method (d), since a synthetic resin-based paint having releasability is applied, when a topcoat is applied after curing, there is a problem that the adhesion between layers with the topcoat is deteriorated. there were.

In the method (e), the plate is autoclaved in the vertical direction, so that the efflorescence component easily flows down to the plate, but the raw plate running horizontally on the conveyor is moved in the vertical direction. However, there is a problem that a complicated apparatus is required for re-arranging the raw materials, and the raw plate is easily deformed.

In view of this situation, the present inventors have conducted intensive studies to solve the above-mentioned problems. As a result, the present inventors have prevented the adhesion and integration of plate materials and the precipitation of efflorescence powder, and The present inventors have found a paint having a function as an undercoat film having good adhesion to an overcoat film, and have reached the present invention.

[0016]

According to the present invention, there is provided an inorganic hydraulic plate material having an uncured surface on which 100 parts by weight (in terms of solid content) of an acrylic emulsion having a Tg of 55 ° C. or higher is used.
The present invention relates to a method for coating an inorganic building material, which is obtained by applying a water-based undercoat paint containing 70 to 300 parts by weight of a pigment as an essential component, and then stacking the obtained coated plate materials and curing in an autoclave.

Hereinafter, the present invention will be described in detail.

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

The water-based primer used in the present invention is an acrylic emulsion 10 having a Tg of 55 ° C. or higher.
Based on 0 parts by weight (solid content), 70 to 300 parts by weight of a pigment and water as a diluent are essential components, and if necessary, various additives, modifiers, a small amount of an organic solvent, etc. are blended. is there.

The acrylic emulsion having a Tg of 55 ° C. or higher includes a copolymer of an alkyl ester monomer of acrylic acid having 1 to 8 carbon atoms, a copolymer of an alkyl ester monomer of methacrylic acid having 1 to 8 carbon atoms, or a copolymer of these monomers. A polymerizable monomer such as a functional monomer such as (meth) acrylic acid, itaconic acid, 2-hydroxyethyl (meth) acrylate, glycidyl (meth) acrylate, (meth) acrylamide, N-methylol (meth) acrylamide, or the like; Styrene, vinyl toluene,
An emulsion resin obtained by appropriately combining monomers such as (meth) acrylonitrile, vinyl chloride, and butadiene and polymerizing in the presence of an emulsifier according to a conventional method is preferable.

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

The glass transition temperature of the acrylic resin (hereinafter referred to as T
g) is 55 ° C. or higher, preferably 65 ° C. or higher, which is advantageous in that blocking (integral adhesion between stacked plate materials) is difficult.

The acrylic resin may be a multistage polymer type, an ordinary dry type or a baked type, in addition to the emulsion polymerized product according to the above-mentioned conventional method, and may further contain zinc oxide, a metal complex salt, a hydrazide compound or the like. Self-crosslinking type resins can also be used.

The pigment may be either an inorganic pigment or an organic pigment, but is preferably an inorganic pigment from the viewpoint of heat resistance, hot water resistance, alkali resistance and the like.

Specific examples include, but are not limited to, coloring pigments such as titanium oxide, iron oxide, and carbon black, and extenders such as calcium carbonate, talc, and barium sulfate. .

Further, with respect to 100 parts by weight (solid content) of an acrylic emulsion having a Tg of 55 ° C. or higher, 70 to 3
Although the mixing ratio is 00 parts by weight, as the pigment content decreases, the adhesion to the base material and the prevention of the attachment of the efflorescence powder are more effective, but the plate material is easily integrated during autoclave curing, and the weight is 70%. Parts or less are not practical, and conversely, as the pigment content increases, the effect of preventing the integration of the plate material increases, but the adhesion to the base material and the adhesion of the efflorescent powder become easy, and 300 parts by weight Beyond that, practicality is lost. Preferably, the amount is 100 to 250 parts by weight based on 100 parts by weight (solid content) of the acrylic emulsion.

Examples of various additives include various dispersants, thickeners, defoamers, preservatives, fungicides, film-forming auxiliaries and the like.

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

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

The inorganic hydraulic material is formed into a plate by a conventional method such as extrusion molding, press molding, integral molding, dry molding, cast molding, and papermaking. Next, if necessary, heat curing (for example, at 40 to 100 ° C. for 4 hours to 2 hours)
(0 hour heating).

The coating time of the undercoat paint can be applied to a plate immediately after molding or to a plate after primary curing, and the coating method is a method such as air spray, airless spray, shower coat, flow coat, roll coat and the like. To apply. The wet application amount is 10 to 150 g / m ² ,
Preferably, it is appropriate to apply the coating so as to have a weight of ²⁰ to 80 g / m ² . Next, the painted raw plates are stacked. It is to be noted that the time for stacking the raw paint sheets is to apply the undercoat paint and to apply the undercoat paint film in a wet state (preferably within 2 minutes after the application) or to at least an extent that the paint film will not be damaged when stacked (half). ) When in a cured state (for example, 1
(Dry at 30 ° C for about 3 minutes or more).

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

Next, the unpainted raw plate that has not been subjected to primary curing is subjected to primary curing and then to autoclave curing. After the primary curing, the primer coated plate is autoclaved (conditions 160 ° -18
(5 ° C, 6Hr to 14Hr) to cure the raw paint plate.

The cured inorganic hydraulic plate material having the undercoating film thus obtained is coated with an intermediate coating, if necessary, according to a usual method, and then coated with a top coating to produce a product. . The paint is not particularly limited, but an aqueous paint such as an acrylic resin emulsion paint is usually used appropriately for both the intermediate paint and the top paint. In applications where the specific gravity of the base material is relatively small and under severe use conditions such as roof tiles, as the intermediate coating, an epoxy resin type, a solvent type such as an isocyanate prepolymer solution, which is relatively easy to penetrate into the base, is used. A sealer may be used.

Further, when the painted plate material is used for a roof tile or the like,
For the purpose of preventing workers from slipping at the time of the enforcement, one bone agent such as silica sand No. 5 to 8 was added to 100 parts by weight of the solid content of the top coat.
You may mix | blend 0-50 weight part.

[0036]

According to the method of the present invention, a specific water-based primer is applied to the surface of an uncured inorganic hydraulic plate material.
Even when the painted plate materials are stacked and cured, the plate materials can be prevented from adhering to each other and being integrated. Further, since the coating film of the water-based undercoat paint is directly formed on the plate material surface, Of efflorescence powder is prevented from being deposited on the sheet material, the adhesion to the sheet material and the topcoat film is good, and therefore, a sheet material product having good production efficiency and excellent durability without peeling of the film is obtained.

[0037]

The present invention will be described below in more detail with reference to examples. In the examples, "parts" and "%" are shown on a weight basis. <Production method of raw plate A> 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 pressed to obtain a raw plate.

Raw plate B Portland cement: 36 parts, silica sand: 58 parts, flat
Iash: 4 parts, polypropylene fiber: 1 part, methyl
Extrude a composition consisting of 1 part cellulose and 67 parts water.
The raw plate was obtained by molding. <Primary curing condition> Condition (a) 8 hours at 40 ° C Condition (b) 6 hours at 60 ° C
I> The composition is shown in [Table 1]. (Example 1) A stainless plate was not properly inserted into the raw plate A.
Stack the pieces and perform primary curing [condition (a)]. This plate
Are transported one by one onto a conveyor, and the undercoat paint a is rolled.
45g / m coating amount with coater^Two(Wet)
Applied. Next, after drying at 140 ° C for 3 minutes, painting
Load the board and cure in an autoclave (180 ° C for 2 hours)
The temperature was raised for 10 hours at the same temperature, followed by curing. Next
Then, the intermediate coating paint i was applied with a roll coater at an application amount of 20 g /
m^Two(Wet) and dried at 120 ° C for 3 minutes
And top coat 1 is applied by airless spray
120g / m ^Two(Wet)
X 13 minutes to dry and harden the top coat. Haute
Efflorescence powder adhesion after lave curing, plate material
Blocking resistance (prevention of integration), coating film after top coating
Test for the adhesion and freeze-thaw properties of
2]. (Example 2) In Example 1, the undercoat paint a was replaced with the undercoat paint.
Coating was carried out in the same manner as in Example 1 except that b was used. (Example 3) In Example 1, the intermediate paint i was replaced with the intermediate paint.
Coating was carried out in the same manner as in Example 1 except that ii was used. (Example 4) Airless spray of undercoat paint c on raw plate B
At 70g / m^Two(Wet)
Was. Next, insert into the frame pallet and perform primary curing (condition b).
Was. Next, remove the primary cured board from the frame pallet,
Load and autoclave cure (raise to 160 ° C for 2 hours)
After warming, curing at the same temperature for 8 hours) and curing. Then middle coat
20g / m of paint i with roll coater^Two(Wet) coating
Apply so that the amount of cloth, dried at 120 ℃ × 10 minutes,
Top coat paint II is applied by airless spray at 110 g / m
^Two(Wet) and dried at 120 ° C for 10 minutes
And the top coat was cured. (Embodiment 5) The plate after the autoclave curing of Embodiment 4
45g / m of paint iii by airless spray^Two(We
t) and dried at 130 ° C for 5 minutes
Except for the above, the coating was performed in the same manner as in Example 4. (Comparative Example 1) In Example 1, the undercoat paint d was used.
Except for the above, the coating was performed in the same manner as in Example 1. (Comparative Example 2) In Example 1, an undercoat paint e was used.
Except for the above, the coating was performed in the same manner as in Example 1. (Comparative Example 3) In Example 1, an undercoat paint after primary curing was used.
Except not painting, load the board in the same way
The plate was cured and the plate was cured. Next, the undercoat paint a
Airless spray, application amount 45g / m^Two(Wet)
And dried at 90 ° C for 5 minutes.
The top coat I was applied by airless spray on the
0 g / m^Two(Wet), 110 ° C x
Let dry for 13 minutes. (Comparative Example 4) In Example 5, an undercoat was applied to the raw original plate B.
Otherwise, load the plate material in the same way and autoclave
After curing, the board was cured. Autoclaved board
The material was cured. Next, airless spray the undercoat c.
At 70 g / m^Two(Wet)
And dried at 90 ° C for 7 minutes.
II application amount 110g / m^Two(Wet)
And dried at 110 ° C for 10 minutes to cure the top coat.
Was.

[0039]

[Table 1] Note 1) A copolymer of styrene / methyl methacrylate / butyl acrylate / methacrylic acid = 16/75/7/2 (T
g 85 ° C) 32.0% solids emulsion, pH
8.0 Note 2) Emulsion with a solid content of 31.8% of a copolymer of styrene / methyl methacrylate / butyl acrylate / methacrylic acid = 30/56/12/2 (Tg 75 ° C.), p
H8.9 Note 3) Styrene / methyl methacrylate / butyl acrylate = 15/55/30 copolymer (Tg50 ° C.) emulsion with a solid content of 48.0%, pH 9.5 Note 4) Sumidur N75 (Bayer) Urethane Corp .; solid content 75 ± 1%, NCO content 16 ± 17%) Note 5) Epoxy resin (Epicoat 828; Shell Chemical Co., Ltd .: Epoxy equivalent 184-194) / curing agent (Epicure H2; Mixture of shell chemical company) = 66/34 Note 6) Eporsion EA-7 (epoxy resin aqueous emulsion; trade name of Kanebouenusc Co., Ltd .: epoxy equivalent: 325 ± 10) / epolsion EB-1 (modified aliphatic) Aqueous emulsion of polyamine resin; trade name, manufactured by Kanebo UNS Co., Ltd .: amine value 107 to 127)
= 50/50 mixture

[0040]

[Table 2]

Claims (4)

(57) [Claims] 1. An aqueous undercoat paint comprising, as an essential component, 70 to 300 parts by weight of a pigment based on 100 parts by weight (in terms of solid content) of an acrylic emulsion having a Tg of 55 ° C. or higher on the uncured surface of an inorganic hydraulic plate material. Is applied, and then the obtained coated plate materials are stacked, and then autoclaved and cured. 2. The method for coating an inorganic building material according to claim 1, wherein a finish coat is applied with a water-based or solvent-based top coat. 3. 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. 4. The method for coating an inorganic building material according to claim 3, wherein said primary curing is heat curing.