JP2006212546A - Formwork plate for concrete and its production method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a formwork plate for concrete with the so-called good peeling diversion nature, excellent in crack resistance and possible to be made to peel from a concrete cured material to be repeatedly used multi times, and to provide its production method. <P>SOLUTION: The formwork plate for concrete is provided by forming respective coating films shown by (A), (B) and (C) on the surface of a substrate in the order of the substrate/a coating film (A)/a coating film (B)/a coating film (C), and its production method is provided. In the formwork plate for concrete, the coating film (A) is a filling coating film (A1) which is formed from a solvent type curing acrylic resin composition containing an acrylic resin with a curing hydroxyl group, an isocyanate type curing agent and an extender or a filling coating film (A2) which is formed from an aqueous emulsion composition containing the extender, (B) is an intermediate coating film which is formed from a moisture-curing type urethane resin composition containing a moisture-curing type urethane resin, a curing catalyst and a water absorbing agent, and (C) is a top coating film which is formed from a curing acrylic resin composition containing an acrylic resin, a curing agent and a color pigment. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a concrete form plate (concrete form plate) and a method for producing the same. More specifically, even if the mold is released (peeled) from a hardened concrete and repeatedly used many times, the surface of the mold plate does not “crack”, and the so-called crack-resistant concrete mold plate and It relates to the manufacturing method.

  As a formwork board for concrete, wooden board material (substrate) without surface coating such as painting may be used as it is, but due to poor hardening of the concrete surface due to deterioration of the wood, leaching out of the wood For the purpose of preventing the biting and adhesion of the conduit to the concrete surface caused by the coloration of the concrete surface and the conduit in the wood being peeled off by the hardened concrete surface, the concrete formwork substrate for concrete is usually painted, etc. In many cases, the coating process is performed.

As a method for coating a concrete mold substrate, for example, a method in which phenol resin-impregnated paper is affixed to the surface of a concrete mold substrate (A), a method in which a plastic powder is melt-bonded (B), or a polyester urethane resin paint, Examples include a method (c) of applying an epoxy resin paint, an acrylic urethane resin paint, or the like.

  However, in the method of attaching phenol resin-impregnated paper as described above to the surface of a concrete formwork substrate or the method of melt-pressing plastic powder, manufacturing equipment and material costs are expensive. Also, in the method of applying polyester urethane resin paint on the surface of a concrete mold substrate, when the obtained concrete mold plate is used, the concrete (usually a large reaction product of water, cement, sand and gravel). It is easy to cause poor curing. Moreover, in the method of applying an epoxy resin paint on the surface of the concrete mold substrate, the weather resistance and crack resistance of the resulting concrete mold plate are insufficient.

  In addition, the method of painting acrylic urethane resin paint on the surface of a concrete formwork substrate can provide a concrete formwork board that is satisfactory in terms of weather resistance and crack resistance. In a general concrete form plate in which two types of paints are applied on the surface of a concrete formwork substrate, if it is used several times for placing concrete, it will “crack” on the surface of the paint film on the formwork plate. ”Occurs, the concrete surface becomes uneven, and the sap in the wood adheres to dark brown contamination. For this reason, the number of times that can be used repeatedly is limited to about 5 to 6 times, and after that, it is subjected to incineration.

  However, in recent years, the prohibition of incineration of waste materials such as formwork for concrete at the construction site has been legalized from the viewpoint of controlling pollution problems, etc., so that contractors can transport used plywood for formwork, Disposal costs have increased significantly.

  In order to reduce such costs as transportation of used formwork plywood and disposal request costs to specialists, the appearance of a formwork for concrete that can be used repeatedly as many times as possible, for example, 10 times or more, is desired.

In addition, it has been proposed so far to use a urethane-based paint as a paint for a concrete mold (for example, see Patent Documents 1 to 11 below).
Patent No. 2866662 (Patent Document 1) includes (A) a monoethylenically unsaturated monomer having a hydroxyl group, (B) a monobasic acid and / or polybasic acid having an ethylenically unsaturated double bond, and (C) A polyurethane resin composition for wood coatings comprising a copolymer obtained by polymerizing other ethylenically unsaturated monomers and polymethylene, polyphenyl, polyisocyanate is disclosed, and Lauan plywood It is described that when it is coated on the surface and dried at room temperature, a coating film having better gloss, alkali resistance, and blocking properties than a conventional polyurethane system is obtained, and it is useful as a paint for concrete mold plywood.

  Japanese Patent Publication No. 07-98918 (Patent Document 2) discloses an acrylic resin having physical properties of a solid hydroxyl value of 10 to 150 mgKOH / g, a glass transition temperature of 20 ° C. to 100 ° C., and a weight average molecular weight of 30,000 to 100,000. An acrylic urethane coating composition for plywood, which is coated with a polyisocyanate-based curing agent, and an acrylic emulsion coating composition is applied to the base of the plywood and dried, and then the acrylic urethane coating composition is further coated thereon. A method for producing a concrete formwork plywood for concrete that is applied and dried in a short time at room temperature is disclosed. After the acrylic emulsion undercoating is applied on the plywood, the acrylic urethane coating composition is coated on the plywood at room temperature in a short time ( 20-25 ° C) drying to obtain a concrete coated mold plywood, and stacking the obtained plywood Somen blocking (adhesive) good drying property without adhesion to the substrate, and concrete release properties are described that is good.

  In Japanese Patent No. 2719045 (Patent Document 3), an undercoating paint which is an alkali-proof filler is applied to a plywood for a mold, and an NCO group-terminated urethane polymer (reaction product of polyoxypropylene polyol + polyisocyanate) is coated thereon. ) And a polyisocyanate are applied as a top coating, and a method for producing a concrete plywood for concrete formwork is disclosed in which the curing of the top coating is accelerated by a catalyst component in the base coating.

  Japanese Patent Laid-Open No. 8-141432 (Patent Document 4) discloses that a plywood for formwork is coated with a water-dispersible resin and / or a water-soluble resin, a filler, and an undercoat paint containing an isocyanate compound, and silicon is coated thereon. A method for producing a coated plywood for a formwork for applying a top-coat paint mainly composed of a modified urethane resin is disclosed, and a method for moisture curing the silicone-modified urethane resin is also described.

  In Japanese Unexamined Patent Publication No. 2000-167814 (Patent Document 5), a primer coating containing a wet curable urethane resin (hard urethane resin) is applied to the surface of a concrete formwork board obtained by heat compression molding of used paper and a binder. And the manufacturing method of the coating board for formwork which coats the undercoat which contains 2 liquid reaction type urethane resin (soft urethane resin) on it is disclosed.

  JP-A-2002-309171 (Patent Document 6) discloses that a NCO group-terminated urethane polymer obtained by reacting a polyether polyol and / or a polyester polyol and a polyisocyanate is coated on a substrate surface, and a hydraulic mixture such as cement is used. A method for preventing the adhesion of the resin is disclosed.

  JP-A-2002-322240 (Patent Document 7) discloses a moisture-curable urethane composition containing an NCO group-terminated urethane polymer obtained by reacting an isocyanate and a polyoxyalkylene polyol and an oxazolidine-terminated urethane compound. The composition is described as having excellent adhesion to the top coating material.

  In Japanese Patent Publication No. 7-2931 (Patent Document 8), a coating resin is applied to the surface of a wooden member in contact with concrete to improve the peeling from the concrete. A concrete release coating comprising a hydrogen group-containing compound and having an organic polyisocyanate that is impermeable to the wooden member and a concrete formwork in which the coating is directly applied to the surface of the plate-like body are disclosed. It is described that addition of silicone or the like is possible, and that smoothness of coating film and concrete surface, ease of peeling, peeling diversion property (10 times or more), etc. are good.

  Japanese Patent Application Laid-Open No. 11-310621 (Patent Document 9) describes a concrete formwork in which a plywood for formwork is coated with a urethane elastomer for concrete form obtained by reacting a terminal NCO group prepolymer and a hydroxyl compound curing agent. A coated plywood is disclosed, and it is described that the mold plywood can be used repeatedly without using a release agent.

  In JP 2002-102792 A (Patent Document 10), a solvent-type permeable sealer having a specific viscosity is applied to a plywood for a mold, and a water-dispersible resin and / or a water-soluble resin and a water-dispersed type are coated thereon. Painted plywood for formwork that contains a polyisocyanate-based primer with a specific viscosity or a solvent-based resin having a hydroxyl group and a solvent-type polyisocyanate, and then coats the primer A water-dispersible sealer containing a water-dispersible resin and / or a water-soluble resin and a water-dispersible polyisocyanate having the above-mentioned specific viscosity is applied to a plywood for a mold and a mold for forming the same. A method for manufacturing a plywood for formwork in which a base coat and a top coat are sequentially applied is disclosed.

  Japanese Patent Application Laid-Open No. 2002-294137 (Patent Document 11) discloses a water-based coating composition containing an acrylic silicone resin emulsion and a polyurethane emulsion, and a coating film formed from the composition has greatly improved crack resistance. It is stated that.

However, when the paints described in these patent documents (1 to 11) are coated on a concrete mold plywood and used as a concrete mold, crack resistance, mold releasability, and interlayer adhesion strength with a substrate , The alkali resistance, the concealability with respect to the substrate surface, and the appearance and state of the coating film are not sufficient.
Japanese Patent No. 2866662 Japanese Patent Publication No. 7-98918 Japanese Patent No. 2719045 Japanese Patent Laid-Open No. 8-142002 JP 2000-167814 A JP 2002-309171 A JP 2002-322240 A Japanese Patent Publication No. 7-2931 JP-A-11-310621 JP 2002-102792 A JP 2002-294137 A

  The present invention seeks to solve the problems associated with the prior art as described above, is excellent in crack resistance, and can be used repeatedly many times after being released (peeled) from a hardened concrete. An object of the present invention is to provide a formwork plate for concrete having good divertability and a method for producing the same.

The formwork plate for concrete according to the present invention is
On the surface of the substrate, the following coating films (A), (B) and (C) are formed in that order (substrate / coating film (A) / coating film (B) / coating film (C)). It is characterized by:
(A) A curable hydroxyl group-containing acrylic resin (i),
Isocyanate curing agent (ii), and
At least one extender pigment selected from the group consisting of calcium carbonate, talc, clay and barium sulfate (iii)
Sealing coating film (A1) formed from a solvent-type curable acrylic resin composition (a1) containing
Or
At least one extender pigment selected from the group consisting of calcium carbonate, talc, clay and barium sulfate (iii)
A sealing coating (A2) formed from an aqueous emulsion composition (a2) containing
(B) Moisture curable urethane resin (iv),
Curing catalyst (v), and
Moisture absorbent (vi)
An intermediate coating film formed from a moisture-curable urethane resin composition containing
(C) a curable hydroxyl group-containing acrylic resin (i),
Isocyanate curing agent (ii), and
At least one coloring pigment (vii) selected from the group consisting of titanium oxide, yellow iron oxide, cyanine blue and carbon black
A top coat film formed from a curable acrylic resin composition comprising:

  In the concrete form plate according to the present invention, the composition for the sealing coating (A) is at least one color selected from the group consisting of titanium oxide, yellow iron oxide, cyanine blue, and carbon black. It may contain pigment (vii).

In the concrete form plate according to the present invention, the composition for the sealing coating film (A1) is any one of a vinyl resin (viii), a thixotropic agent (ix) and a suspending agent (x). It may contain more than seeds.

  In the concrete form plate according to the present invention, the composition for the sealing coating (A2) is made of at least one resin selected from the group consisting of acrylic resin, vinyl acetate resin, epoxy resin and urethane resin. May be included.

Moreover, in the formwork board for concrete which concerns on this invention, the composition for the said sealing coating films (A2) may contain the isocyanate type hardening | curing agent (ii) further.
In the concrete form plate according to the present invention, the composition for the intermediate coating film (B) further contains one or more of a leveling agent (xi) and an antifoaming agent (xii). Also good.

  In the concrete form plate according to the present invention, the composition for the top coat (C) is further any one of a precipitation inhibitor (x), a leveling agent (xi) and an antifoaming agent (xii). It may contain more than seeds.

  In the method for producing a concrete form plate according to the present invention, the coating films (A), (B) and (C) are applied to the surface of the substrate in the order (substrate / coating film (A) / coating film ( B) / coating film (C)).

  The above-mentioned concrete formwork plate is excellent in crack resistance, and the concrete kneaded can be poured into a formwork provided with the formwork plate, and the obtained hardened concrete can be easily peeled off. Since almost no hardened concrete remains on the formwork plate, the same formwork can be used many times (eg 10 times or more) without repainting. Economic cost, resource saving, construction / civil engineering work It is preferable in terms of properties.

Hereinafter, the formwork plate for concrete and the manufacturing method thereof according to the present invention will be specifically described.
<Concrete formwork>
In the formwork plate for concrete according to the present invention, the sealing coating film (A), the intermediate coating film, and (B) the top coating film (C) are formed in this order on the surface of the concrete substrate. The concrete formwork substrate will be described.

[Concrete formwork substrate]
There are no particular restrictions on the material of the concrete formwork substrate used in the present invention. , China, Sen, Beech, etc. In the present invention, a plywood for formwork that is preferably used from the standpoint of a substrate, particularly strength and dimensional stability, is “Japanese agricultural and forestry standard for plywood for concrete formwork” (Ministry of Agriculture and Forestry Notification No. 932, June 30, 1967). ) Is desirable.

[Seamless coating (A)]
As the sealing coating (A), a sealing coating (A1) formed by applying and curing a sealing coating, that is, a solvent-type curable acrylic resin composition (a1), on the surface of the base material, Or there exist two aspects of the sealing coating film (A2) formed by apply | coating and hardening an aqueous | water-based emulsion composition (a2).

  Such a sealing coating film (A) is used in the concrete form plate of the present invention, for adhesion to the substrate surface and the intermediate coating film (B), to conceal the substrate conduit, and to smooth the substrate surface. It excels in processability (processing), alkali resistance, water resistance, filling of recesses, and abrasiveness of dry coating film.

<Seamless coating (A1)>
The solvent-type curable acrylic resin composition (a1) for the sealing coating (A1) includes a curable hydroxyl group-containing acrylic resin (i), an isocyanate curing agent (ii), and calcium carbonate, talc, clay. And at least one pigment component (iii) selected from the group consisting of barium sulfate.

In addition, the solvent-type curable acrylic resin composition (a1) for the sealing coating film (A1), in addition to the organic solvent that is usually contained, is also the following vinyl resin (x), coloring pigment ( Any one or more of vii), thixotropic agent (ix) and suspending agent (x) may be contained.
[Curable hydroxyl group-containing acrylic resin (i)]
The curable hydroxyl group-containing acrylic resin (i) is composed of (meth) acrylic acid and / or (meth).
An acrylic polyol resin containing a component unit derived from an acrylate ester and a component unit derived from a hydroxyl group-containing (meth) acrylate ester, wherein each component unit is a block in the resin (i) May be present, or may be present at random. The resin (i) may be modified with other segments usually used in paints such as polyether and polyether polyol, and has a functional group other than a hydroxyl group, such as a carboxyl group or an alkoxyphenyl group. You may do it.

Such a curable hydroxyl group-containing acrylic resin (i) is, for example,
(A): (meth) acrylic acid and / or (meth) acrylic acid ester, which is a vinyl monomer that is copolymerizable with a hydroxyl group-containing (meth) acrylic acid ester and does not contain a hydroxyl group, and a hydroxyl group-containing (meth) acrylic (B): hydroxyl group-containing (meth) acrylic acid ester is homopolymerized, or (c): a monomer for modification (eg, carboxyl group-containing) at the time of copolymerization of (a) above. Monomer, alkoxysilyl group-containing monomer, polyoxyalkylene group-containing monomer, etc.)
It can be produced by a conventional method. The order of addition and mixing of the monomers is not particularly limited.

As (meth) acrylic acid ester and other vinyl monomers (excluding hydroxyl group-containing (meth) acrylic acid ester, the same applies hereinafter), conventionally known ones can be widely used. For example, methyl (meth) acrylate, ethyl (meth ) Acrylate, n-propyl (meth) acrylate, i-propyl (meth) acrylate, n-butyl (meth) acrylate, i
-Butyl (meth) acrylate, sec-butyl (meth) acrylate, t-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate (Meth) acrylic acid ester monomers having a hydrocarbon substituent such as cyclohexyl (meth) acrylate, phenyl (meth) acrylate, benzyl (meth) acrylate, dibromopropyl (meth) acrylate;
Styrene derivatives such as styrene, α-methylstyrene, vinyltoluene;
Polymerizable unsaturated nitriles such as acrylonitrile and methacrylonitrile;
Acrylamide monomers such as N-methylol (meth) acrylamide, N-methoxymethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide;
Vinyl esters such as vinyl acetate;
Epoxy group-containing monomers such as glycidyl (meth) acrylate and (meth) acryl glycidyl ether;
Examples include basic monomers such as dimethylaminoethyl (meth) acrylate and diethylaminoethyl (meth) acrylate. Among them, (meth) acrylic acid ester monomers and styrene are preferable.

These can be used independently and can also use 2 or more types together.
Specific examples of the hydroxyl group-containing (meth) acrylic acid ester include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, and 2-hydroxybutyl (meth). Acrylate, 3-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 3-chloro-2-hydroxypropyl (meth) acrylate, di-2-hydroxyethyl fumarate, mono-2-hydroxyethyl-mono Ring-opening adducts of ethylene oxide and propylene oxide to butyl fumarate, 2-hydroxyethyl (meth) acrylate or 2-hydroxypropyl (meth) acrylate,
Adducts of the above hydroxyl group-containing (meth) acrylic acid esters with ε-caprolactone or adducts of polyethylene glycol (and / or polypropylene glycol mono (meth) acrylate) with ε-caprolactone ("Placcel FM series, FA series") Various kinds of hydroxyalkyl esters of α, β-ethylenically unsaturated carboxylic acids, such as the monomer of, and the trade name of caprolactone addition monomer manufactured by Daicel Chemical Industries, Ltd.,
Examples thereof include hydroxyl group-containing (meth) acrylic acid ester monomers such as 2-hydroxyethyl (meth) acrylate or 2-hydroxypropyl (meth) acrylate dimer and trimer.

When ε-caprolactone is used in combination as described above, it is preferable in that the crack resistance of the coating film using the curable hydroxyl group-containing acrylic resin (i) is improved.
In the present invention, the curable hydroxyl group-containing acrylic resin (i) may be modified with other segments, and in order to obtain such a modified curable hydroxyl group-containing (meth) acrylic resin (i), for example, The modified group-containing monomer may be copolymerized with the above-described (meth) acrylic acid, (meth) acrylic acid ester, hydroxyl group-containing (meth) acrylic acid ester and the like.

In what is marketed as a curable hydroxyl group-containing acrylic resin, for example,
“Acridic 51-302” (Dainippon Ink & Chemicals, Inc., solvent: butyl acetate, nonvolatile content 50%),
"Acridic A-850" (Dainippon Ink & Chemicals, Inc., solvent: toluene,
Butyl acetate, non-volatile content 70%),
“Hitaroid 3083-70B” (manufactured by Hitachi Chemical Co., Ltd., solvent: toluene, methyl ethyl ketone, isobutyl acetate, non-volatile content 70%),
“Aulac APO-101” (manufactured by Akira Otake Shin Chemical Co., Ltd., solvent: toluene, methyl isobutyl ketone, nonvolatile content 60%),
“Aulac APO-301” (manufactured by Akira Ohtake Shin Chemical Co., Ltd., solvent: xylene, 65% non-volatile content) or the like is used.

The number average molecular weight (Mn) of the curable hydroxyl group-containing acrylic resin (i) [measurement method: G
PC. Conversion using standard polystyrene calibration curve. ] Is usually in the range of 500 to 50,000, preferably 1,800 to 30,000,
Weight average molecular weight (Mw) of this curable hydroxyl group-containing acrylic resin (i) [Measurement method: GPC
. Conversion using standard polystyrene calibration curve. ] Is usually in the range of 5,000 to 100,000, preferably 20,000 to 70,000. If the number / weight average molecular weight is less than the above range, the drying property tends to be low, and the coating strength tends to be low and the weather resistance tends to be poor. Tends to decrease, and the non-volatile content in the paint tends to decrease.

The GPC measurement conditions are as follows:
(B) Equipment manufacturer and model number: Water Asia Limited,
Used in combination with equipment (components) of the following model numbers:
1) Waters 410 Differential Refractometer
2) Waters 600S Controller
3) Waters 717 Plus Autosampler,
(B) Column: TSK G2000H, TSK G4000H, TSK GMH-M,
(C) Eluent: tetrahydrofuran,
(D) Column temperature: 40 ° C
(E) Flow rate: 1 ml / min,
(F) Detector: 600S Controller.

  A hydroxyl value (hydroxyl value) of preferably 50 to 180 mgKOH / g, more preferably 70 to 100 mgKOH / g, has an appropriate curing reactivity, and the coating film obtained has a small amount of remaining hydrophilic groups. It is desirable in that the film has excellent water resistance and excellent acid resistance and alkali resistance.

The curable hydroxyl group-containing acrylic resin (i) is usually often used in the form of a varnish containing a solvent used in the synthesis of the resin.
The Tg of the curable hydroxyl group-containing acrylic resin (i) is usually 6 to 130 ° C., preferably 30.
When the temperature is about 120 ° C., the coating film formed becomes soft, and when it is too high, the coating film tends to be non-uniform, and the coating film is too hard to easily cause cracks.

The polymerization method of the curable hydroxyl group-containing acrylic resin (i) may be a known polymerization method such as a solution polymerization method, a bulk polymerization method, and an emulsion polymerization method, but generally a solution polymerization method is used.
For example, in the case of the solution polymerization method, the monomer mixture may be copolymerized in the presence of an organic solvent and a polymerization initiator. As the organic solvent, commonly used organic solvents such as isopropyl alcohol, n-butanol, butyl cellosolve, toluene, xylene, “Sorvesso 100, Solvesso 150” manufactured by Esso Corporation can be used. Moreover, as a polymerization initiator, normally used polymerization initiators such as azobisisobutyronitrile, benzoyl peroxide, cumene hydroperoxide, and the like can be used. Furthermore, a chain transfer agent such as 2-mercaptoethanol, n-octyl mercaptan, n-dodecyl mercaptan, α-methylstyrene dimer can be used as necessary.
[Isocyanate curing agent (ii)]
Examples of the isocyanate curing agent (ii) used in the present invention include compounds having two or more isocyanate groups (polyisocyanate), blocked polyisocyanates, and the like.

  Specific examples of the polyisocyanate include diphenylmethane-4,4′-diisocyanate, 1,6-hexamethylene diisocyanate (HDI), 1,4-tetramethylene diisocyanate, 1-methyl-2,4-diisocyanate cyclohexane, Bis (4-isocyanatophenyl) methane, 4-methoxy-1,3-phenylene diisocyanate, 2,4- and 2,6-tolylene diisocyanate, tolylene diisocyanate (TDI), 6-isopropyl-1,3-phenylene Examples thereof include diisocyanate, isophorone diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, hydrogenated diphenylmethane-4,4′-diisocyanate. Further, examples thereof include adducts of the above polyisocyanates, polyfunctional isocyanate compounds such as isocyanurates, and compounds such as dimers and trimers thereof.

  In the case of formwork plywood and wooden flooring, heating the material (base material) to a temperature of usually 100 ° C. or more may lead to a decrease in physical properties. For this reason, a high-temperature drying method using a blocked isocyanate as a polyisocyanate is usually not used much.

The equivalent ratio (NCO / OH) of the isocyanate group content of the isocyanate curing agent (ii) to the hydroxyl group content of the curable hydroxyl group-containing acrylic resin (i) is usually 0.8 to 1.6, preferably 0.9. ~ 1.2. The hydroxyl group content (hydroxyl value) is the number of milligrams of potassium hydroxide corresponding to the hydroxyl group in 1 g of the sample.

  The isocyanate group content and hydroxyl group content described above can be found in columns [0020] to [0026] of JP-A-8-157769 (Japanese Patent Application No. 6-301039) relating to the application of the present applicant. It is a value obtained in the same manner as described.

As such an isocyanate-based curing agent,
“Millionate MR-200” (manufactured by Nippon Polyurethane Industry Co., Ltd., nonvolatile content 100%
, Methylene diisocyanate),
“SUMIDUR 44V-20” (manufactured by Sumika Bayer Urethane Co., Ltd., nonvolatile content 100%, methylene diisocyanate),
"Dismodur L-75" (manufactured by Bayer AG, solvent: ethyl acetate, non-volatile content 75%, tolylene diisocyanate prepolymer),
“Olestar P45-75MT” (manufactured by Mitsui Takeda Chemical Co., Ltd., solvent: toluene, methyl isobutyl ketone, non-volatile content 75%, tolylene diisocyanate prepolymer),
Etc. are used.
[External pigment (iii)]
Examples of extender pigments used in the present invention include calcium carbonate, talc, clay and barium sulfate.

These extender pigments function as "extreme pigments" that are transparent in the coating film and do not hide the surface to be coated (substrate surface), and have functions such as filling of recesses and reduction of paint costs. .
These extender pigments can be used alone or in combination of two or more. When two or more types are used in combination, the total amount thereof may be the same as the amount used when used alone.

Among these extender pigments, calcium carbonate is particularly preferably used alone or in combination with another one.
As calcium carbonate, for example,
“NS-300, 400” (manufactured by Nippon Flour Industry Co., Ltd.),
“CaCO ₃ Super SS” (manufactured by Kyushu Calcium Co., Ltd.),
“CaCO ₃ Sunlight No. 300” (manufactured by Takehara Kogyo Co., Ltd.),
“Calcium carbonate NN-200” (manufactured by Nitto Flourishing Co., Ltd.)
As talc, for example,
“Talc MS” (manufactured by Nippon Talc Co., Ltd.) or the like is used.

The extender pigments such as calcium carbonate may contain a small amount of other extender pigments that are inert and excellent in alkali resistance, water resistance, thermal stability, and the like. Examples of such other extender pigments include white porcelain clay and kaolin.
[Optional ingredients]
[Colored pigment (vii)]
As the color pigment, yellow iron oxide, titanium oxide, cyanine blue, carbon black and the like are preferably used.

  These color pigments have the advantage that they do not easily change color because they are not attacked by components such as alkali in the concrete, and are selected according to the required color tone of the formwork for concrete. In the present invention, instead of such a colored pigment (vii), other pigments stable to alkali or the like may be used together with such a colored pigment (vii), and examples thereof include red iron oxide.

Yellow iron oxide is a yellow pigment that is used as necessary, and there are both natural products and synthetic products (wet and dry types). Among the synthetic products, yellow iron oxide by the wet method is present in the sealing coating (A1). Excellent dispersibility, coloring power / hiding power, weather resistance, acid resistance / alkali resistance, and contributes to improving the solvent resistance of the coating film. As this yellow iron oxide, for example, “Tarox LL-XLO” (manufactured by Titanium Industry Co., Ltd., hydrated ferric oxide), “BAYFERROX 920” (manufactured by Bayer, hydrated ferric oxide) and the like are used. It is done.
[Vinyl resin (viii)]
The vinyl resin (viii) is used as a regulator of the hardness or glass transition point of the curable hydroxyl group-containing acrylic resin (i), and can improve the adhesion of the dried coating film to wood and the crack resistance.

Specific examples of such vinyl resins (viii) include vinyl chloride / vinyl acetate copolymer resins, vinyl chloride / vinyl acetate / vinyl alcohol copolymer resins, vinyl chloride / vinyl isobutyl ether copolymer resins, vinyl chloride. -Vinyl chloride copolymer resins such as vinyl propionate copolymer resins; chlorinated rubber resins; chlorinated olefin resins; (meth) acrylic resins other than the above curable hydroxyl group-containing acrylic resins (i), (meth) acrylic ester resins or Examples include acrylic resins such as (meth) acrylic acid ester copolymer resins; styrene / butadiene copolymer resins. Among these, a vinyl chloride / vinyl acetate copolymer having a curable hydroxyl group is particularly preferable in that it has reactivity with isocyanate and good adhesion to wood. Examples of such vinyl resins that have been put on the market include, for example, “Vinylite VAGD”, “Vinylite VAGH”, “Vinylite VAGC” (all manufactured by Dow Chemical Co., Ltd.), and all have curable hydroxyl groups. Vinyl chloride / vinyl acetate copolymer resin).
[Thixotropic agent (ix)]
Thixotropic agents (thixotropic regulators) (ix) are organic, inorganic, and complex. In organic systems, hydrogenated castor oil, amide, polyethylene oxide, vegetable oil polymerized oil, and surfactant are inorganic. For example, silica and bentonite are used in the system, and amide / polyethylene is used in the composite system. This contributes to storage stability of the paint and prevention of sagging of the paint during coating. Adversely affects the flattening of As this far-changing agent, for example, “Erogil 200” (manufactured by Nippon Aerosil Co., Ltd.), “Dispalon 4200-20” (manufactured by Enomoto Kasei Co., Ltd., polyethylene oxide type) and the like are used. It is done.
[Precipitating agent (x)]
Examples of the precipitation inhibitor (x) include stearates of Al, Ca, and Zn, organic bentonite, polyethylene wax, amide wax, lecithin, and alkyl sulfonate. As what is marketed, for example, “Disparon 4200-20” (manufactured by Enomoto Kasei Co., Ltd.) is used.

The curable hydroxyl group-containing acrylic resin (i) (solid content) contained in the composition (paint) for the sealing coating (A1) is volatilized in the composition for the sealing coating (A1). In a total amount of 100% by weight of the components excluding the solvent, ie, the solid content, preferably 5 to 60% by weight, more preferably 10 to 45% by weight, particularly preferably 15 to 40% by weight, Preferably in the cured coating film (A1) in an amount of 4 to 56% by weight, more preferably 10 to 45% by weight, particularly preferably 15 to 40% by weight,
The extender pigment (iii) such as calcium carbonate is preferably 20 to 85% by weight, more preferably 30 to 75% by weight in the cured coating film, and the acrylic resin (i) described above.
(Solid content) It is preferably contained in an amount of 70 to 800 parts by weight in total with respect to 100 parts by weight.

The isocyanate curing agent (ii) is used in such an amount that the isocyanate group (—NCO) content is theoretically equivalent to the hydroxyl group (—OH) content in the acrylic resin (i). However, it is 25-15 with respect to 100 parts by weight of the acrylic resin (i) (solid content).
In other words, the ratio ([NCO] / [OH]) of the number of isocyanate groups in the isocyanate curing agent (ii) and the number of hydroxyl groups in the curable hydroxyl group-containing acrylic resin (i) is 0 parts by weight. , 0.8 / 1.0 to 1.2 / 1.0 is preferably contained in the paint.

When the curable hydroxyl group-containing acrylic resin (i) is contained in the above amount in the composition for the sealing coating (A1), it is preferable because it has sufficient pigment binding force and fluidity,
When the isocyanate-based curing agent (ii) is contained in the above-mentioned amount, for example, in the sealing paint obtained by mixing immediately before use, adhesion to a substrate, particularly wood, water resistance, Preferred because alkali resistance is good,
If the amount of extender pigment (iii) is included in the total amount as described above, a smooth coating surface can be obtained because the filling of the wood surface into the conduit is sufficient, and the fluidity of the paint is also good. It is preferable because of its excellent paintability.

In addition, when the composition for the sealing coating (A1) contains the color pigment (vii), the vinyl resin (viii), the thixotropic agent (ix), the precipitation inhibitor (x), etc., if necessary. Is
The color pigment (vii) is 10 to 70 parts by weight with respect to 100 parts by weight of the acrylic resin (i) (solid content).
The vinyl resin (viii) is 5 parts per 100 parts by weight of the acrylic resin (i) (solid content).
In an amount of 0-300 parts by weight,
The far-changing agent (ix) is 0.5 to 100 parts by weight with respect to 100 parts by weight of the acrylic resin (i) (solid content).
In an amount of 15 parts by weight,
The precipitation inhibitor (x) may be contained in an amount of 0.1 to 8 parts by weight with respect to 100 parts by weight of the acrylic resin (i) (solid content).

Further, if the coloring pigment (vii) used as necessary is contained in the above amount, it is preferable because sufficient concealment is obtained,
When the vinyl resin (viii) is contained in the amount as described above, it is preferable because adhesion to wood and flexibility of the coating film are improved,
When the thixotropic agent (xii) is contained in the above amount, it is preferable because it can prevent dripping from the edge of the paint,
It is preferable that the suspending agent (x) is contained in the amount as described above because the effect of preventing the precipitation of the pigment is obtained.

The composition for the coating film (A1) as described above (sealing paint, sealing agent) is produced by a conventional method, and is usually made into one-pack type or two-pack type depending on the type of curing agent. Used.
Such a sealing paint is cured at room temperature (20 to 30 ° C.) depending on the type of the curable hydroxyl group-containing acrylic resin (i) and the like, and the type of the isocyanate curing agent (ii) (for example, Depending on the block isocyanate, it becomes a one-component heat curable.

  This sealing paint is used in the form of a solvent-type paint. Examples of the solvent include organic solvents such as toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, and butyl acetate. The amount of the solvent added is not particularly limited, but from the standpoint of adjusting the viscosity and improving the coatability, the amount of the coating material (including the solvent) is 100% by weight, for example, 2 to 40% by weight. Is used in an amount.

In addition, when this coating material for the sealing coating film (A1) is used as a two-component type, a main ingredient component containing a curable hydroxyl group-containing acrylic resin (i) (a) so that reactive components do not contact each other (
Resin component) and a curing agent component containing an isocyanate curing agent (ii). Components that are non-reactive with the curable hydroxyl group-containing acrylic resin (i) or isocyanate curing agent (ii), such as extender pigments such as calcium carbonate and talc, colored pigments such as yellow iron oxide, and vinyl resins are the main component components Although it may mix | blend with any of (resin component) and a hardening | curing agent component, it is normally mix | blended with a main ingredient component normally. The thixotropic agent and the suspending agent are usually blended with the main component together with the sedimentation and aggregation components such as resin and pigment. The same applies to the intermediate coating and top coating described below.

<Seamless coating (A2)>
The aqueous emulsion composition (a2) for the sealing coating (A2) contains at least one pigment component (iii) selected from the group consisting of calcium carbonate, talc, clay and barium sulfate.

In addition, the aqueous emulsion composition (a2) for the sealing coating film (A2) may contain one or more of an isocyanate curing agent (ii) and a color pigment (vii).
[Aqueous emulsion]
The resin contained in the aqueous emulsion is not particularly limited, and examples of the aqueous emulsion include acrylic emulsion, vinyl acetate emulsion, epoxy emulsion, and urethane emulsion. Of these, acrylic emulsions and vinyl acetate emulsions are preferred.

Moreover, it is desirable that the polymer provided as an aqueous emulsion has a functional group containing active hydrogen such as an amino group, a hydroxyl group, or a carboxyl group.
For example, about acrylic emulsion, 2-hydroxyethyl acrylate, 2-ethylhexyl acrylate, etc. are added to a copolymer of acrylic acid, methacrylic acid, or an alkyl ester thereof and a monomer such as styrene, thereby adding a hydroxyl group. Can be synthesized.

  As for the vinyl acetate emulsion, a polymer having a hydroxyl group can be synthesized similarly by adding polyvinyl alcohol to a vinyl acetate polymer, vinyl acetate-ethylene copolymer or the like.

There is no restriction | limiting in particular as an acrylic resin provided with the form of the acrylic emulsion used by this invention, The single polymer of a conventionally well-known acrylic monomer or a copolymer with another monomer can be used. Examples of acrylic monomers include (meth) acrylic acid;
(Meth) acrylic acid such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, t-butyl (meth) acrylate, hexyl (meth) acrylate A C _1-10 alkyl ester;
(Meth) acrylic acid C _3-12 cycloalkyl esters such as (meth) acrylic acid cyclohexyl;
(Meth) acrylic acid aryl esters such as (meth) acrylic acid phenyl; (meth) acrylic acid aralkyl esters such as benzyl (meth) acrylate;
Hydroxy C _2-6 alkyl (meth) acrylates such as 2-hydroxyethyl (meth) acrylate and 3-hydroxypropyl (meth) acrylate;
Alkylamino-alkyl (meth) acrylates such as dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, diethylaminopropyl (meth) acrylate; (meth) acrylamide, N-methyl (meth) acrylamide, methylol (meth) acrylamide (Meth) acrylamide or a derivative thereof such as alkoxymethyl (meth) acrylamide;
Epoxy group-containing (meth) acrylates such as glycidyl (meth) acrylate;
Examples include (meth) acrylonitrile.

Examples of monomers copolymerized with acrylic monomers include aromatic vinyl monomers such as styrene, α-methylstyrene, pt-butylstyrene, and vinyl toluene;
Fatty acid vinyl monomers such as vinyl propionate;
Esters of unsaturated polyvalent carboxylic acids such as maleic anhydride, maleic acid, fumaric acid, itaconic acid or unsaturated polyvalent carboxylic acid derivatives such as dimethyl maleate and diethyl fumarate;
N-substituted maleimides such as N-phenylmaleimide;
Examples thereof include olefinic monomers such as ethylene and propylene. These monomers may be used alone or in combination of two or more.

There is no restriction | limiting in particular as a vinyl acetate resin provided with the form of a vinyl acetate type emulsion, A conventionally well-known thing can be used, and the copolymer of polyvinyl acetate or a vinyl acetate, and another monomer can be used. Other monomers copolymerized with vinyl acetate include, for example, olefins such as ethylene;
(Meth) acrylic acid, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, (meth ) T-butyl acrylate, hexyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, stearyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (Meth) acrylic monomers such as (meth) acrylate and glycidyl acrylate;
Maleate esters such as diethyl maleate, dipropyl maleate, dibutyl maleate, dihexyl maleate, dioctyl maleate, 2-ethylhexyl maleate and the like, and fumaric acid esters corresponding thereto;
Vinyl esters such as vinyl propionate, vinyl caprylate, vinyl caproate, vinyl versatate; monomers having a carboxy group such as crotonic acid, itaconic acid, itaconic acid half ester, maleic acid, maleic acid half ester;
Examples include styrene, vinyl chloride, methyl vinyl ketone, acrylonitrile, methacrylonitrile, acrolein, and crotonaldehyde. These monomers may be used alone or in combination of two or more.

  The epoxy resin provided in the form of an epoxy-based emulsion is not particularly limited and conventionally known epoxy resins can be used. For example, glycidyl ether type epoxy resins such as bisphenol type epoxy resins, glycidyl ester type epoxies such as glycidyl phthalate ester, etc. Examples thereof include resins, glycidyldiamine type epoxy resins such as tetraglycidyldiaminodiphenylmethane, and cyclic oxirane type epoxy resins such as 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate. These may be used alone or in combination of two or more.

  The urethane resin provided in the form of a urethane-based emulsion is not particularly limited, and conventionally known urethane resins can be used. For example, a mixture of polyols and / or polyamines is used as the first component, and an average of 2 or more per molecule. And a urethane-based resin obtained by reactive curing using a polyisocyanate containing a terminal isocyanate group as a second component.

  Examples of the polyols include polyester polyol, polycarbonate polyol, polyester polycarbonate polyol, and polyether polyol. Examples of the polyisocyanate include TDI (tolylene diisocyanate), MDI (methyl diphenyl diisocyanate), IPDI (isophorone diisocyanate), and the like. Examples thereof include HMDI (hexamethylene diisocyanate). These may be used alone or in combination of two or more.

These aqueous emulsions may be used alone or in combination of two or more.
These aqueous emulsions preferably have a solid content of 30 to 50% by weight from the viewpoint of stable properties.

Among those marketed as such an aqueous emulsion, “Boncoat EC-100” (Dainippon Ink Chemical Co., Ltd., water-based acrylic emulsion), “KR Bond F-29” (Koyo Sangyo Co., Ltd., water-based) Vinyl acetate emulsion).
[Isocyanate curing agent (ii)]
The aqueous emulsion composition (a2) can be used as a one-component paint containing the extender pigment (iii), but an isocyanate curing agent (ii) may be used in combination. This isocyanate type curing agent (ii) is the same as the corresponding component in the sealing coating film (A1) or the solvent-type curable acrylic resin composition (a1).

When the isocyanate curing agent (ii) is used in combination, the adhesion of the sealing coating (A2) to wood is improved, and the functional group having active hydrogen of the polymer provided as the aqueous emulsion and the isocyanate A cross-linked structure is formed by the reaction with the isocyanate group of the system curing agent (ii), which is preferable in terms of improving the water resistance and alkali resistance of the sealing coating film (A2).

  The extender pigment (iii) and the optional color pigment (vii) are the same as the corresponding components in the sealing coating film (A1) or the solvent-type curable acrylic resin composition (a1). is there.

The resin provided in the form of an aqueous emulsion contained in the composition for the sealing coating (A2) is a component excluding water of the solvent contained in the aqueous emulsion composition (a2), that is, the total solid content. In 100% by weight, preferably 10 to 40% by weight, more preferably 15 to 30% by weight, particularly preferably 20 to 25% by weight, and preferably in the cured sealing coating (A2) 10-40% by weight, more preferably 15-30% by weight, particularly preferably 20-25% by weight,
The extender pigment (iii) is preferably 20 to 85% by weight, more preferably 30 to 75% by weight in the cured coating film, and the resin (solid content) 100 provided in the form of the above-mentioned aqueous emulsion. It is contained in an amount of preferably 70 to 800 parts by weight with respect to parts by weight.

  It is desirable to add the isocyanate-based curing agent (ii) excessively in consideration of the fact that a part of the isocyanate-based curing agent (ii) is consumed by the water in the aqueous emulsion (water-based paint) (a2). The addition amount (ii) of the isocyanate curing agent is usually 10 to 40 parts by weight with respect to 100 parts by weight of the resin (solid content) provided in the form of the aqueous emulsion.

If used, the color pigment (vii) is usually contained in an amount of 10 to 70 parts by weight with respect to 100 parts by weight of the resin (solid content) provided in the form of the aqueous emulsion.
When the resin (solid content) provided in the form of an aqueous emulsion is contained in the above amount in the composition for the sealing coating (A2), it has sufficient pigment binding force and fluidity. Therefore, when the extender pigment (iii) is contained in the total amount as described above, a smooth coating surface can be obtained because the filling ability of the wood surface into the conduit portion is sufficient, and the paint It is preferable because it has good fluidity and excellent paintability.

It is preferable that the isocyanate-based curing agent (ii) is contained in the amount as described above, since adhesion to a substrate, particularly wood, water resistance and alkali resistance are improved, and the color pigment (vii) is preferable. It is preferable that it is contained in the amount as described above because sufficient concealment can be obtained.

[Intermediate coating film (B)]
The intermediate coating film (B) is a moisture containing an intermediate coating, that is, a moisture curable urethane resin (iv), a curing catalyst (v), and a moisture absorbent (vi) on the surface of the sealing coating film (A). It is formed by applying and curing a curable urethane resin composition.

In addition, the composition for the intermediate coating film (B) may be any one of the leveling agent (xi) and the antifoaming agent (xii) in addition to the organic solvent similar to the above that is usually included. 1 or more types may be included.

The intermediate coating film (B) is provided with an intermediate coating composition containing such a moisture curable urethane resin component, and can provide a concrete form plate excellent in crack resistance. Also, interlayer adhesion between the sealing coating (layer) (A) and the intermediate coating (layer) (B), and interlayer adhesion between the intermediate coating (layer) (B) and the top coating (C) Excellent in adhesion (adhesion). Therefore, the mold can be used repeatedly and can be used repeatedly, for example, 10 times or more, preferably 15 times or more, particularly preferably 20 times or more. Thus, there is an effect that the disposal cost after use can be significantly reduced.
[Moisture-curing urethane resin (iv)]
As the moisture curable urethane resin (prepolymer) (iv), conventionally known ones can be widely used. For example, JP-A-6-157987, JP-A-11-116652, JP-A-2000-129115. Urethane resin compositions described in JP-A Nos. 2003-128942, 2000-37659, etc., particularly those used for moisture-curing urethane resin compositions or paints can be used.

Moisture-curing urethane resin (prepolymer) is obtained by, for example, reacting the above-mentioned isocyanate curing agent (ii) such as diisocyanate with glycols (polyol), leaving a free isocyanate group at the molecular end. can get.
<Polyol>
Examples of the polyol include those described in columns [0044] to [0045] of JP-A No. 2000-37659 previously proposed by the applicant of the present application.

  Specifically, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, polypropylene glycol, butylene glycol, dibutylene glycol, tributylene glycol, polybutylene glycol, 1, Dihydric alcohols such as 5-pentanediol, neopentyl glycol, 1,6-hexanediol, 1,10-decanediol, alkanediol, cyclohexanedimethanol; glycerol, trimethylolpropane (TMP), 1,2,6- Hexanetriol, trimethylolethane, 2,4-dihydroxy-3-hydroxymethylpentane, 1,1,1-tris (bishydroxymethyl) propane, 2,2-bis (hydroxymethyl) butano Trihydric alcohols such as -3; tetrahydric alcohols such as pentaerythritol and diglycerol; pentahydric alcohols such as arabit, ribitol, and xylitol (pentit); hexavalent alcohols such as sorbit, mannitol, galactitol, and allozulcit A polyglycol compound having up to about 10 carbon atoms such as a polyhydric hydroxy compound such as polyglycerol and polytetramethylene glycol, a polyester polyol derived from phthalic anhydride, sebacic acid, a fatty acid, an epoxy resin, an epoxy polyol ( Alkanolamine-modified epoxy), polyether polyol or acrylic polyol.

Of these, ethylene glycol, propylene glycol, 1,6-hexanediol, glycerol, trimethylolpropane, pentaerythritol, polyester polyol, and acrylic polyol are preferable.
<Isocyanate curing agent (ii)>
In the present invention, the isocyanate curing agent (ii) is a polyisocyanate curing agent as described in columns [0052] to [0065] of JP-A 2000-37659 previously proposed by the present applicant. The isocyanate curing agent (ii) described above may be used although it may be selected as appropriate.

  In the present invention, each component of the polyol and the polyisocyanate is in a quantity ratio such that an isocyanate-terminated urethane polymer is formed so as to be a moisture-curing type, that is, a quantity ratio in which the isocyanate group amount exceeds the hydroxyl group amount. It suffices if the reaction is carried out with [(NCO group) amount> (OH group) amount]. Such a moisture curable urethane resin (iv) (urethane prepolymer) usually has a ratio [NCO group / OH group] of the equivalent of the isocyanate group contained in the polyisocyanate to the equivalent of the hydroxyl group contained in the polyol. Exceeding, preferably 1.5 or more, the upper limit is [NCO group / OH group] is 10.0 or less, preferably 8.0 or less in consideration of adverse effects such as curing delay and increase in foaming during moisture curing. It is preferable that the reaction is performed as follows.

  For example, a hydroxyl group-containing monomer or prepolymer (eg, polyethylene glycol, polymethylene glycol, polybutylene glycol or a derivative thereof) and an isocyanate curing agent (ii) (eg, tolylene diisocyanate or a prepolymer thereof) are converted into a hydroxyl group. What is necessary is just to make it react by using the quantity ratio which becomes rich in the amount of isocyanate groups compared with quantity.

  The polymerization temperature and polymerization time for obtaining such a moisture curable urethane resin (iv) (urethane prepolymer) are not particularly limited. For example, after mixing a polyol and a polyisocyanate usually under a nitrogen gas stream, 60 to It is good to make it react at 100 degreeC for 3 to 8 hours. In the reaction, an appropriate amount of an organic metal salt urethane catalyst such as dibutyltin dilaurate may be added at any stage.

In such a moisture curable urethane resin (iv) (or one containing a solvent, etc.),
“MT Olester M95-50A” (manufactured by Mitsui Takeda Chemical Co., Ltd., moisture-curing urethane resin varnish, solvent: toluene, xylene, ethyl acetate, 3-methoxybutyl acetate, nonvolatile content 50%),
“MT Olester M75-50E” (Mitsui Takeda Chemical Co., Ltd., moisture-curing urethane resin varnish, solvent: toluene, xylene, ethyl acetate, nonvolatile content 50%),
"Coronate 2014" (manufactured by Nippon Polyurethane Industry Co., Ltd., moisture curable urethane resin varnish, solvent: xylene, 50% non-volatile content)
Etc. are used.
[Curing catalyst (v)]
In the present invention, as the curing catalyst (v) for the moisture curable urethane resin (iv) used, conventionally known moisture curing catalysts can be widely used. For example, dibutyltin bistriethoxysilicate, dibutyltin dimethoxide, Dibutyltin diacetate, dibutyltin dilaurate, butyltin tri-2-ethylhexoate, lead-2-ethyl octoate, iron-2-ethylhexoate, cobalt-2-ethylhexoate, manganese-2-ethylhexo Organic acid carboxylic acids such as acrylate, zinc-2-ethylhexoate, stannous caprylate, tin naphthenate, tin oleate, tin butyrate, tin naphthenate, zinc naphthenate, cobalt naphthenate, zinc stearate Metal salts of; alkoxyaluminum compounds; benzyltriethylammo Quaternary ammonium salts such as um acetate; lower fatty acid salts of alkali metals such as potassium acetate, sodium acetate and lithium oxalate; amine-based curing agents such as dialkylhydroxylamines such as dimethylhydroxyamine and diethylhydroxyamine It is done.

These curing catalysts may be used alone or in combination of two or more.
Examples of commercially available curing catalysts (vi) for urethane resins (vii) include “U-CAT 651M” (manufactured by San Apro Co., Ltd., a curing catalyst for moisture-curing urethane resins, modified amines, Non-volatile content 100%), "NY-1" (manufactured by Nippon Polyurethane Industry Co., Ltd.,
Tertiary amine, nonvolatile content 100%) and the like are used.
[Moisture absorbent (vi)]
The moisture absorbent (dehydrating agent) (vi) prevents gelation of the coating by removing moisture contained in the intermediate coating, and contributes to excellent storage stability of the coating. As the moisture absorbent, as long as it does not have reactivity with concrete, conventionally known ones can be widely used, and either organic or inorganic can be used, anhydrous gypsum (CaSO ₄ ), synthetic zeolite-based adsorbent (product) Name: molecular sieve etc.), ortho esters such as methyl orthoformate and methyl orthoacetate, orthoborate esters, silicates and isocyanates (trade name: additive T1). These moisture absorbents may be used alone or in combination of two or more. For example, “Additive OF” (manufactured by Sumitomo Bayer Urethane Co., Ltd.) or the like is used.
[Leveling agent (xi)]
Examples of the leveling agent (xi) include polybutyl acrylate, polymethylsiloxane, a modified silicone compound, and a fluorosurfactant. As what is marketed, for example, “Polyflow No. 7, Polyflow No. 77” (manufactured by Kyoeisha Yushi Co., Ltd.), “BYK-354, BYK-360P” (Germany, manufactured by Big Chemie) and the like are used. .
[Antifoaming agent (xii)]
Examples of the antifoaming agent (xii) include silicone-based, oxyalkylene-based, prolunic-type and mineral-based antifoaming agents, such as “Floren AC-300” (manufactured by Kyoeisha Yushi Co., Ltd.), “BYK-”. 088, BYK-065, BYK-P104 "(manufactured by Big Chemie, Germany)," Disparon OX-70 "(manufactured by Enomoto Kasei Co., Ltd.) and the like are used.

In the present invention, it is preferable to include an antifoaming agent in consideration of the smoothness of the obtained coating film and the prevention of foaming of the coated surface due to bubbles entrained in the paint during coating.
The moisture curable urethane resin (iv) (solid content, ie, non-volatile content excluding the solvent) is a component excluding the solvent which is a volatile content in the composition for the intermediate coating film (B), ie, the total solid content is 100 weight. % In an amount of preferably 30 to 99% by weight, more preferably 40 to 98% by weight,
The curing catalyst (v) is 0.05 to 5 parts by weight, more preferably 0.1 to 2 parts by weight with respect to 100 parts by weight of the moisture curable urethane resin (iv) (solid content). It is desirable that it is contained in the composition (solid content) for the coating film (B).

  The moisture absorbent (vi) is preferably 1.0 to 40 parts by weight, more preferably 1.0 to 5 parts by weight with respect to 100 parts by weight of the moisture curable urethane resin (iv) (solid content). It is desirable to be included in the amount of.

If the moisture curable urethane resin (iv) is contained in the above amount in the composition for the intermediate coating film (B), the viscosity becomes suitable for coating and handling, and further, it is made of a crack-resistant product. Because it is possible to provide an excellent formwork plate for concrete,
When the curing catalyst (v) is contained in the amount as described above, it is preferable because the drying time and the pot life are suitable for the coating process.
Further, it is preferable that the moisture absorbent (vi) is contained in the above amount because it is effective for preventing the influence of moisture in the air.

In addition, if the above leveling agent (xi), antifoaming agent (xii) and the like are included in the composition for the intermediate coating film (B) as necessary,
The leveling agent (xi) is in an amount of 0.05 to 5.0 parts by weight with respect to 100 parts by weight of the moisture curable urethane resin (iv) (solid content).
The antifoaming agent (xii) may be contained in an amount of 0.02 to 2.0 parts by weight with respect to 100 parts by weight of the moisture curable urethane resin (iv) (solid content).

In addition, if the leveling agent (xi) used as necessary is contained in the above amount, the resulting coating film is preferably a smooth coating surface,
When the antifoaming agent (xii) is contained in the amount as described above, it is preferable because foaming is prevented during coating.

  The composition for the intermediate coating film (B) as described above is produced by a conventional method. Usually, it depends on the composition of the coating material, the storage environment of the coating material such as temperature and humidity, and the coating environment. It can be used as a two-component type in some cases.

  Such an intermediate coating is usually cured at room temperature by moisture (water) such as in the air. The intermediate coating is usually used as a solvent type. The amount of the solvent to be added is not particularly limited, but is used in an amount of, for example, 10 to 60% by weight in 100% by weight of the intermediate coating material (including the solvent).

  In the present invention, since the first layer coating film (A) and the third layer top coating film (C) are sufficiently colored, the second layer intermediate coating film (B It is not necessary to add a pigment to the coating material, and it is usually used as a clear. However, if the first and third layers are insufficiently colored, A small amount of a color pigment may be added.

[Top coat film (C)]
The top coat film (C) is a curable composition comprising a top coat paint, that is, a curable hydroxyl group-containing acrylic resin (i), an isocyanate curing agent (ii) and a color pigment (vii) on the surface of the intermediate coat film (B). It is formed by applying and curing an acrylic resin composition.

  In addition, the composition for the top coating film (C) usually contains the same organic solvent as described above, and also includes a precipitation inhibitor (x), a leveling agent (xi), an antifoaming agent. Any one or more of the agent (xii) may be contained.

  The top coat film (C) formed by applying and curing such a top coat paint is used in the concrete form plate of the present invention for adhesion (interlaminar peel strength) with the intermediate coat film (B), smoothness of the coat film. When the concrete form plate of the present invention having the top coat film (C) is used, the obtained hardened concrete is excellent in surface smoothness, and the formwork is excellent. The concrete scraps solidified on the surface do not remain and do not easily damage the plywood for the formwork, and the formwork can be used repeatedly, and the formwork can be used repeatedly, for example, 10 times or more. The number of times is preferably 15 times or more, particularly preferably 20 times or more. Furthermore, there is an effect that the disposal cost after use can be significantly reduced as compared with a normal coating form plate.

The curable hydroxyl group-containing acrylic resin (i), the isocyanate curing agent (ii) and the color pigment (vii) contained in the top coating composition are the same as the corresponding components in the sealing coating film (A) or the sealing coating composition. It is the same thing.

The curable hydroxyl group-containing acrylic resin (i) contained in the composition for the top coat film (C) is:
In the component excluding the solvent contained in the composition for the top coat (C), that is, in the total solid content of 100% by weight, preferably 40 to 80% by weight, more preferably 50 to 75% by weight, In the cured top coat film (C), preferably 30 to 70% by weight, more preferably 40 to 65% by weight,
The isocyanate-based curing agent (ii) contains, in the composition, the hydroxyl group (—OH) value in the curable hydroxyl group-containing acrylic resin (i) and the isocyanate group (—NCO in the isocyanate-based curing agent (ii). In general, the reaction ratio ([NCO] amount / [OH] amount) is 0.8 / 1.0 to 1.2 / 1.0 so that the reaction ratio is theoretically equivalent. In quantity
The color pigment (vii) is preferably 1 to 30% by weight, more preferably 5 to 20% by weight, and 100% by weight of the acrylic resin (i) (solid content). What is necessary is just to use in the quantity of 1-30 weight part with respect to a part.

If the curable hydroxyl group-containing acrylic resin (i) is contained in the above amount in the composition for the top coat film (C), the viscosity is suitable for coating and handling, and the weather resistance is good. Is preferable,
When at least one coloring pigment (vii) selected from the group consisting of yellow iron oxide, titanium oxide, cyanine blue and carbon black is contained in the above amount, the hiding property of the plywood substrate is improved. Preferably,
It is preferable that the isocyanate-based curing agent (ii) is contained in the above amounts because the coating performance such as water resistance and alkali resistance is improved.

If necessary, if the composition for the top coat film (C) contains the precipitation inhibitor (x), antifoaming agent (xii), leveling agent (xi), etc.,
The precipitation inhibitor (x) is in an amount of 0.5 to 6 parts by weight with respect to 100 parts by weight of the acrylic resin (i) (solid content).
The defoamer (xii) is 0.2 to 1.0 part by weight with respect to 100 parts by weight of the acrylic resin (i) (solid content).
The leveling agent (xi) is 0 with respect to 100 parts by weight of the acrylic resin (i) (solid content).
. It may be contained in an amount of 05 to 5.0 parts by weight.

Further, it is preferable that the precipitation inhibitor (x) used as necessary is contained in the above amount because it is effective in preventing precipitation of the pigment,
When the antifoaming agent (xii) is contained in the above amount, it is preferable because it prevents foaming of the coated surface,
When the leveling agent (xi) is contained in the above amount, the obtained coating film is preferable because it becomes a smooth coating surface.

The composition for the top coat film (C) as described above (top coat paint, top coat agent) is produced by a conventional method, and is usually used as a one-pack type or a two-pack type depending on the type of the curing agent.
Depending on the type of the curable hydroxyl group-containing acrylic resin (i) and the like, such a top coat can be cured at room temperature and can be baked and dried at 50 to 70 degrees to shorten the drying time. Moreover, this top coat is usually used as a solvent type. The amount of the solvent to be added is not particularly limited, but is used in an amount of 2 to 40% by weight in 100% by weight of the top coating material (including the solvent), for example.

  As described above in detail, in the concrete mold plate according to the present invention, as a surface covering of the concrete mold plywood, in a preferable mode in the first layer, acrylic containing a large amount of extender pigment as described above. The surface of the wood can be smoothed by applying urethane resin paint as a sealant. Further, the second layer is coated with a moisture-curing urethane coating as described above to improve the crack resistance of the concrete form plate. In addition, after the intermediate coating, the acrylic urethane resin paint containing the color pigment is applied to the third layer as described above, which makes it easy to release after placing concrete. .

<Manufacturing method of formwork plate for concrete>
The method for producing a formwork plate for concrete according to the present invention comprises applying the coating materials for the coating films (A), (B) and (C) to the surface of the substrate and curing them, in that order (substrate / coating film). (A) / coating film (B) / coating film (C)).

More specifically, preferred embodiments are as follows.
(1) Application of the first layer sealing paint When applying the first layer sealing paint, in order to fill the unevenness of the plywood surface and make it smooth, a conveyor for conveying the formwork plywood, A knife coater made of a thin steel plate attached perpendicularly (at right angles) to the direction of travel is used. Usually, even if it is applied only once with a knife coater, filling of the sealing paint into the conduit portion is often incomplete, and sufficient smoothness is often not obtained. Therefore, it is usually desirable to repeat the knife coater coating 2 to 3 times using the same sealing paint so that the total coating amount (uncured product) per square meter is 80 to 150 g.
(2) Application of the second layer of intermediate coating In the coating of the second layer of intermediate coating, for example, the same intermediate coating is repeatedly applied 1 to 3 times on a roll coater, and the total coating amount (uncured) It is desirable to paint so that a thing) will be 20-90g per square meter.
(3) Application of the third layer of top coat In the coating of the third layer of top coat, for example, the same top coat is repeatedly applied once or twice by a roll coater, and the total coating amount (uncured product) is It is desirable to paint so that it will be 20-90g per square meter.
(4) Drying method As the drying method for the first layer sealing paint, the second layer intermediate coating, and the third layer top coating, room temperature drying is usually adopted, but depending on the component composition, etc. It is also possible to perform forced drying at a heating temperature of 80 ° C.

In the case of room temperature drying, the drying time of the first layer when the first layer and the second layer are applied is 1 to 3 hours, and the drying time of the second layer when the second layer and the third layer are applied is 0. ~ 3 hours.
That is, when the second layer and the third layer are applied repeatedly, the second layer may be dried for about 3 hours and sufficiently dried, and then the third layer may be applied again, but immediately after the second layer is applied (2 It is also possible to apply the third layer repeatedly (Wet-on-Wet method) in the uncured state of the drying time of the layer: 0 hour.

In addition, after coating the third layer, it takes 5 hours or more to prevent adhesion of undried paint films as it becomes possible to stack painted plywood and store, transport, etc. Drying time is required.
<Effect of the invention>
The formwork plate for concrete according to the present invention is extremely difficult to crack and can be easily peeled off from a hardened concrete, and can be used for placing concrete by repeating a single coating many times (eg 10 times or more). It can be used twice or more times as many times as the conventional plywood formwork by ordinary painting, so that both workability and economy are suitable. Therefore, it is possible to reduce the number of concrete molds used at the construction site, efficiently build a building having a good outer surface, and save resources.

  Since the concrete form plate of the present invention can be reused many times in this way, if the concrete form plate of the present invention is used, it will be used for concrete placing work, causing cracks and waste products. It becomes possible to save the disposal cost of the formed mold plywood and the like to ½ or less compared to the case of using the conventional product. Furthermore, the use of the concrete form plate of the present invention has a great effect on the preservation of wood resources and the effective use of resources.

[Example]
Hereinafter, the present invention will be described more specifically based on examples, but the present invention is not limited to the examples.
[Preparation of coating composition]
The first layer sealing paints A, B, C, D (sealing A, B, C, D) shown in Tables 3 to 6 below, and the intermediate coating for the second layer shown in Tables 7 and 8 below Paints A and B (intermediate clears A and B) and top coats A and B (top coats A and B) for the third layer shown in Tables 9 and 10 below were prepared.

  The composition, physical properties and the like of each component in the following table are as shown in Table 1 below.

The test methods for the crack resistance test and JAS standard test are as follows.
<Crack resistance test>
Cut out test pieces of length x width = 15 cm x 15 cm from each painted test plate, leave these test pieces in an incubator at 80 ° C ± 3 ° C for 2 hours, and then incubate at -20 ° C ± 3 ° C. The process of leaving for 2 hours is repeated twice and then left at room temperature until the temperature of the specimen reaches room temperature. Record the number of cracks on the surface of the specimen. This is repeated until many cracks are generated on the surface of the test piece.
<JAS standard test>
Table 2 below shows the plane tensile test method, cold heat repeat test method, and alkali resistance test method defined in JAS (Japanese Agricultural Standard for Concrete Formwork Plywood, “4, Quality of Board Surface”).

<Manufacture of concrete form plates>
As shown in the above table, the sealing paint A, which is obtained by adding a curing agent to the main ingredient component for the first-layer sealing paint A and stirring sufficiently, is applied to a plywood for concrete molds at room temperature (25 ° C.). The coating was repeated three times every hour with a knife coater, and the coating amount (uncured product) per square meter was about 90 g.

  After applying the sealing paint A and drying it for 1 hour, the intermediate coating material A obtained by adding a curing agent to the main ingredient component for the second-layer intermediate coating material A is continuously applied at room temperature with a roll coater. The coating was applied twice so that the coating amount per square meter (uncured product) was about 50 g.

  After the intermediate coating material A is applied and dried for 2 hours, the top coating material A obtained by adding a curing agent to the main component for the third-layer top coating material A is continuously applied on a roll coater at room temperature. The coating was repeated so that the coating amount (uncured product) per square meter was about 50 g.

The coated mold plywood was dried at room temperature for 48 hours to produce a concrete mold board. <Test>
About the obtained formwork board for concrete, the crack-proof test and the JAS standard test were implemented.

  The results are shown in Table 12.

<Manufacture of concrete form plates>
In Example 1, instead of the first-layer coating A, the sealing coating B is used, and the second-layer intermediate coating A is used instead of the intermediate coating B as the third-layer top coating A. Instead, a concrete form plate was produced in the same manner as in Example 1 except that the top coat B was used.
<Test>
About the obtained formwork board for concrete, the crack-proof test and the JAS standard test were implemented.

  The results are shown in Table 12.

<Manufacture of concrete form plates>
A concrete form plate was produced in the same manner as in Example 1 except that the intermediate coating material B was used in place of the intermediate coating material A for the second layer in Example 1.
<Test>
About the obtained formwork board for concrete, the crack-proof test and the JAS standard test were implemented.

  The results are shown in Table 12.

<Manufacture of concrete form plates>
A concrete form plate was produced in the same manner as in Example 1, except that the sealing paint C was used in place of the first-layer sealing paint A in Example 1.
<Test>
About the obtained formwork board for concrete, the crack-proof test and the JAS standard test were implemented.

  The results are shown in Table 12.

<Manufacture of concrete form plates>
In Example 1, instead of the first layer coating A, the coating D is replaced with the second layer intermediate coating A, and the intermediate coating B is replaced with the third layer top coating A. A concrete form plate was produced in the same manner as in Example 1 except that the top coat B was used.
<Test>
About the obtained formwork board for concrete, the crack-proof test and the JAS standard test were implemented.

The results are shown in Table 12.
[Comparative Example 1]
<Manufacture of concrete form plates>
In Example 1, the coating material A for the first layer was applied so that the application amount (uncured product) per square meter was about 50 g, and the intermediate coating material for the second layer was not applied. A concrete form plate was produced in the same manner as in Example 1 except that the coating amount (uncured product) per square meter was about 50 g for the third-layer top coating A.
<Test>
About the obtained formwork board for concrete, the crack-proof test and the JAS standard test were implemented.

The results are shown in Table 12.
[Comparative Example 2]
<Manufacture of concrete form plates>
In Comparative Example 1, the coating material A is applied so that the application amount (uncured product) per square meter is about 90 g, and the top coating material A is applied about 40 g per square meter (uncured product). A concrete form plate was produced in the same manner as in Comparative Example 1 except that coating was performed.
<Test>
About the obtained formwork board for concrete, the crack-proof test and the JAS standard test were implemented.

The results are shown in Table 12.
[Comparative Example 3]
<Manufacture of concrete form plates>
In Comparative Example 1, instead of the first layer coating A, the coating B is applied so that the coating amount per square meter (uncured product) is about 90 g, and the third layer top coating is applied. A concrete form plate was produced in the same manner as in Comparative Example 1, except that the top coating material B was applied in place of A so that the coating amount (uncured product) per square meter was about 90 g.
<Test>
About the obtained formwork board for concrete, the crack-proof test and the JAS standard test were implemented.

The results are shown in Table 12.
[Comparative Example 4]
<Manufacture of concrete form plates>
In Example 1, the first layer coating A was applied and dried, then the third layer top coating A was applied and dried, and then the second layer intermediate coating A was applied. A concrete form plate was produced in the same manner as in Example 1.
<Test>
About the obtained formwork board for concrete, the crack-proof test and the JAS standard test were implemented.

The results are shown in Table 12.
[Comparative Example 5]
<Manufacture of concrete form plates>
In Comparative Example 1, instead of the first-layer sealing paint A, the sealing paint C was applied so that the coating amount (uncured product) per square meter was about 90 g, and the third-layer top-coating paint was applied. A concrete form plate was produced in the same manner as in Comparative Example 1 except that A was coated so that the coating amount (uncured product) per square meter was about 90 g.
<Test>
About the obtained formwork board for concrete, the crack-proof test and the JAS standard test were implemented.

The results are shown in Table 12.
[Comparative Example 6]
<Manufacture of concrete form plates>
In Comparative Example 1, instead of the first layer coating A, the coating D is applied so that the coating amount per square meter (uncured product) is about 90 g, and the third layer top coating is applied. A concrete form plate was produced in the same manner as in Comparative Example 1 except that the top coat B was applied instead of A.
<Test>
About the obtained formwork board for concrete, the crack-proof test and the JAS standard test were implemented.

  The results are shown in Table 12.

  The formwork plate for concrete according to the present invention is remarkably excellent in crack resistance, and also has a coated surface excellent in water repellency, slip resistance, scratch resistance, etc. The mold releasability is dramatically improved compared to conventional products. When building concrete structures such as condominiums, buildings, bridges, etc., the number of times the same form plate can be transferred without repainting. The construction cost and industrial waste disposal cost can be reduced.

Claims (13)

The following coating films (A), (B) and (C) were formed on the surface of the substrate in that order (substrate / coating film (A) / coating film (B) / coating film (C)). Concrete formwork:
(A) A curable hydroxyl group-containing acrylic resin (i),
Isocyanate curing agent (ii), and
At least one extender pigment selected from the group consisting of calcium carbonate, talc, clay and barium sulfate (iii)
Sealing coating film (A1) formed from a solvent-type curable acrylic resin composition (a1) containing
Or
At least one extender pigment selected from the group consisting of calcium carbonate, talc, clay and barium sulfate (iii)
A sealing coating (A2) formed from an aqueous emulsion composition (a2) containing
(B) Moisture curable urethane resin (iv),
Curing catalyst (v), and
Moisture absorbent (vi)
An intermediate coating film formed from a moisture-curable urethane resin composition containing
(C) a curable hydroxyl group-containing acrylic resin (i),
Isocyanate curing agent (ii), and
At least one coloring pigment (vii) selected from the group consisting of titanium oxide, yellow iron oxide, cyanine blue and carbon black
A top coat film formed from a curable acrylic resin composition comprising: The solvent-type curable acrylic resin composition, wherein the sealing coating (A) further comprises at least one color pigment (vii) selected from the group consisting of titanium oxide, yellow iron oxide, cyanine blue and carbon black. The formwork plate for concrete according to claim 1, formed from (a1) or an aqueous emulsion composition (a2).   The formwork for concrete according to claim 1 or 2, wherein the sealing coating film (A1) is further formed from a solvent-type curable acrylic resin composition (a1) containing a vinyl resin (viii).   The concrete formwork according to any one of claims 1 to 3, wherein the sealing coating (A1) is further formed from a solvent-type curable acrylic resin composition (a1) containing a thixotropic agent (ix). Board. The formwork for concrete according to any one of claims 1 to 4, wherein the sealing coating (A1) is further formed from a solvent-type curable acrylic resin composition (a1) containing a precipitation inhibitor (x). Board.   The said coating film (A2) was formed from the aqueous emulsion composition (a2) containing at least 1 sort (s) of resin chosen from the group which consists of an acrylic resin, a vinyl acetate resin, an epoxy resin, and a urethane resin. Or the formwork board for concrete of 2.   The formwork plate for concrete according to claim 1, 2 or 6, wherein the sealing coating film (A2) is further formed from an aqueous emulsion composition (a2) containing an isocyanate curing agent (ii).   The formwork board for concrete according to any one of claims 1 to 7, wherein the intermediate coating film (B) is further formed from a moisture-curable urethane resin composition containing a leveling agent (xi). The formwork board for concrete according to any one of claims 1 to 8, wherein the intermediate coating film (B) is further formed from a moisture-curable urethane resin composition containing an antifoaming agent (xii). The formwork plate for concrete according to any one of claims 1 to 9, wherein the top coat film (C) is further formed from a curable acrylic resin composition containing a precipitation inhibitor (x).   The formwork board for concrete according to any one of claims 1 to 10, wherein the top coat film (C) is further formed from a curable acrylic resin composition containing a leveling agent (xi). The formwork board for concrete according to any one of claims 1 to 11, wherein the top coat film (C) is further formed from a curable acrylic resin composition containing an antifoaming agent (xii).   Each coating film of the above (A), (B) and (C) is formed on the surface of the substrate in the order (substrate / coating film (A) / coating film (B) / coating film (C)). The method for producing a formwork plate for concrete according to any one of claims 1 to 12, wherein: