JPH08142032A - Release paint for concrete formwork and painted panel for concrete formwork - Google Patents

Abstract

(57) [Summary] [Purpose] A coated panel for concrete formwork having a large number of diversions is obtained by using a silicone-modified urethane resin. [Structure] An aqueous liquid containing an aqueous solution and / or an aqueous emulsion containing a water-soluble polymer and a coating material containing a filler and an isocyanate compound are applied as an undercoat on a wood material panel, and then modified with silicon. Apply a mold release paint whose main component is urethane resin.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coated panel for concrete formwork used in construction work or civil engineering work. The purpose of that is concrete
The coating and concrete for concrete molds, which does not interfere with the curing of the mold, is easy to release from the curing concrete and the mold panel, and has releasability over a long period of time, so that it is frequently used. -To a painted panel for formwork.

[0002]

2. Description of the Related Art Concretes that can be repeatedly used conventionally
Japanese Patent No. 1830888,
1830889 and JP-A-3-20081 are known. That is, in the above-mentioned prior art, by blending a high boiling point plasticizer, silicone, or the like into a polyurethane-based paint, the plasticizer or silicon gradually migrates to the surface and oozes out, so that a curing concrete and a mold panel are formed. It is easy to release from and can be used repeatedly.

[0003]

However, in the above-mentioned prior art, if the high boiling point plasticizer and silicon in the coating material are all exuded, the releasability is no longer exhibited and the number of times of diversion is naturally limited. . Usually, when building large structures such as buildings, bridges and dams, it takes a long time to assemble the formwork panels, and it is not uncommon to leave them alone after the assembly. In the meantime, the plasticizer and silicon that have exuded to the surface of the panel due to wind and rain are washed away. Furthermore, if left for a long period of time, all the plasticizer may be washed away before the cement is placed. In this case, the releasability is no longer exhibited.

Further, the surface of the formwork panel is slimy due to the oozing plasticizer, and dust easily adheres to it. The adhesion of the dust causes defective curing of the concrete, affects the smoothness of the surface of the released concrete, and deteriorates the gloss. Therefore, it may be necessary to perform a troublesome work of wiping the panel surface with a waste cloth or the like before placing the concrete.

[0005]

Therefore, the present inventors have completed the present invention as a result of intensive studies to solve the above problems. That is, the coated panel for concrete formwork of the present invention comprises an aqueous solution (F) containing a water-soluble polymer and / or an aqueous solution (G) containing an aqueous emulsion as a main component.
And filler (H) and polyisocyanate compound (B)
After applying a base paint containing the above compound on a wood-based material panel, a mold release paint for a concrete mold having a long-term releasability containing a silicone-modified urethane resin as a main component is used. This silicone-modified urethane resin is a terminal obtained by the reaction of the reactive silicone (A) with the polyisocyanate compound (B) or the reaction of the reactive silicone (A) with the excess polyisocyanate compound (B) in an equivalent ratio. Urethane prepolymer having isocyanate group (C)
And a polyol (D) / or an amine (E), or a moisture curing of a terminal isocyanate prepolymer (C).

In this mold release coating, the reactive silicone (A) is bonded to the urethane resin matrix by a urethane bond and does not leak to the surface to exhibit releasability for a long time. Keep doing

The reactive silicon (A) used in the present invention is
It has two or more reactive hydroxyl groups at the end or side chain of dimethylpolysiloxane or at the end and side chain. In the silicone-modified urethane resin, the weight% of the reactive silicon bonded is 2 to 40. If the amount of the reactive silicon bonded is small, the releasability is poor.
On the other hand, if it exceeds 40%, the adhesiveness to the underlying layer will be poor and delamination will occur, preferably 5 to 25%.

The polyisocyanate compound (B) used in the base paint and the silicone-modified urethane resin of the present invention is toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), polymeric diphenylmethane diisocyanate (Cr-MDI), xylylene diisocyanate (XDI). , Isophorone diisocyanate (IPDI), hexamethylene diisocyanate (H
DI), hydrogenated TDI, hydrogenated MDI, hydrogenated X
DI or a modification thereof or a mixture thereof.

The synthesis of the organosilicon-modified urethane prepolymer (C) having a terminal isocyanate group according to claims 4 and 5 is obtained by reacting the reactive silicone (A) with the above-mentioned polyisocyanate compound (B). You may use together the polyol (D) and amine (E) which are described below. The reaction between the reactive silicone (A) and the polyisocyanate (B) is such that the equivalent of the polyisocyanate compound (B) is 1.1 or more relative to 1 equivalent of the reactive silicon (A), and 1 in the case of moisture curing. A value of 0.3 to 7.0 is preferable. When used for the reaction with the polyol (D), the amine (E) or the reactive silicon (A), the equivalent ratio is preferably 2.0 to 30. This prepolymerization reaction may be carried out at 40 ° C. to 120 ° C. for 2 hours to 24 hours in a nitrogen stream in the same manner as the usual urethane formation reaction. At this time, a desired prepolymer can be obtained in a short time by adding an organotin compound and a tertiary amine as a catalyst.

On the other hand, the polyol (D) / or amine (E) / or reactive silicon (A) which reacts with the silicone-modified urethane prepolymer (C) is the following compound.

The polyol (D) is ethylene glycol, glycerin, trimethylolpropane, triethanolamine, ethylenediamine, diglycerin, pentaerythritol, sucrose, bisphenol A,
A polyoxyalkylene polyol obtained by addition-polymerizing alkylene oxide with bisphenol F, polycaprolactone polyol, valerolactone polyol, or a mixture thereof is used. Especially ethylenediamine,
The propylene oxide adduct of bisphenol A and polycaprolactone polyol are preferred.

The amine is 3,3'-dichloro-
4,4'-diaminodiphenylmethane, tetrachloro-
4,4′-diaminodiphenylmethane, trimethylenebis-4-aminobenzoate, polytetramethyloxide-di-p-aminobenzoate, methylenebis (2
-Ethyl-6-methylaniline) and the like used as an amine curing agent for urethane resins. The reactive silicon (A) used as the curing agent is defined in the present invention.

These polyols (D), amines (E),
The reactive silicon (A) can be used alone or in combination of two or more kinds. The polyol (D) and the amine (E) mentioned here are not limited to the above compounds, and any one widely applicable to urethane resins can be used.

The present coating composition exhibits sufficient releasability only with a silicone-modified urethane resin, but if necessary, pigments, dehydrating agents, diluents, catalysts, inorganic fillers, leveling agents, thickeners, and antioxidants. Agents and ultraviolet absorbers can be added as appropriate. In the case of a two-pack type, these may be added to the polyol side in advance.

Generally, silicon is said to have a good releasability and is used in various fields. A urethane resin containing a plasticizer having a high boiling point has also been proposed as a release agent for this purpose. The silicone or plasticizer oozes out from the paint and intervenes on the surface of the coating film, thereby exerting a releasing effect. However, once all of the compounded silicone or plasticizer has migrated, the releasability is lost and the number of diversions is naturally limited. Further, due to the presence of silicon or a plasticizer on the surface, dust may adhere to the surface of the concrete when it is placed at a construction site, and this dust may be transferred to the concrete surface that has been placed, resulting in a loss of gloss.

On the other hand, in the coating material of the present invention, dimethylpolysiloxane bonded to the surface or inside of the resin is present, and this does not migrate to the concrete side even after releasing the hardened concrete and the formwork panel. Not present in the paint. As a result, the coating composition of the present invention continues to exhibit releasability for a long period of time. That is, the conventional coating material is transferred to concrete in which silicone or a plasticizer as an additive hardens, and the releasing effect decreases as the number of times of conversion increases, whereas in the releasing coating material of the present invention, Reactive silicon that exhibits releasability is always fixed in the paint, and the releasability does not change even if the number of times of diversion increases.

Recently, it is difficult to manufacture a concrete formwork plywood which has a good surface condition due to the exhaustion of raw wood and the like, and there are usually many irregularities on the surface, and it is necessary to apply a large amount of paint. Although it is possible to directly apply the above-mentioned mold release paint to this surface, there is a drawback in that the finished concrete form painting panel becomes expensive. Therefore, according to the present invention, a relatively inexpensive concrete form coating panel can be obtained by applying a water-based paint as an undercoat to make the surface smooth and then applying the release paint. It was

The undercoat paint of the present invention means an aqueous solution (F) containing a water-soluble polymer and / or an aqueous solution (G) containing an aqueous emulsion as a main component, a filler (H) and a polyisocyanate compound (B). Is a paint that contains

In the present invention, the water-soluble polymer (F) means
Polyvinyl alcohol, itaconic acid, maleic anhydride,
Modified polyvinyl alcohol copolymerized with acrylic acid,
Water-soluble polymers such as polyacrylamide, carboxymethylcellulose, methylcellulose, sodium alginate, sodium polyacrylate, starch, casein, glue, maleic acid-vinyl ether copolymer and derivatives thereof included.

The aqueous emulsion (G) means polyvinyl acetate, ethylene-vinyl acetate copolymer, styrene-butadiene copolymer, methyl methacrylate-butadiene copolymer, acrylic ester copolymer. , Acrylic acid ester-vinyl acetate copolymer, acrylonitrile-butadiene copolymer and the like, and emulsions obtained by modifying these.

It is particularly preferable to use an aqueous solution and / or an aqueous emulsion of a polymer compound having an acetoacetyl group in the molecule. These improve the adhesiveness with the above-mentioned release paint for concrete mold and also improve the water resistance.

As an aqueous solution of a polymer compound having an acetoacetyl group in the molecule, an acetoacetylated polyvinyl alcohol obtained by acetoacetylating a water-soluble polymer compound such as polyvinyl alcohol, hydroxyalkyl cellulose and starch. , Acetoacetylated hydroxyalkyl cellulose, acetoacetylated starch and the like. Further, as an aqueous emulsion of a polymer compound having an acetoacetyl group in the molecule, an acetoacetylated copolymer emulsion obtained by emulsion copolymerizing a monomer containing an acetoacetyl group and α and β ethylenic monomers And a polymer emulsion using a polymer compound having an acetoacetyl group in the molecule as an emulsifier.

The filler (H) used for the purpose of the filling effect and the concealing effect in the present invention includes inorganic fillers such as clay, aluminum hydroxide, silica sand, talc, calcium carbonate, titanium oxide, and wood powder. , Organic fillers such as short fibers can be used.

The polyisocyanate compound (B) in the composition of the base paint is selected from those used for the silicone-modified urethane resin, and is a cross-linking agent which reacts with hydroxyl groups and the like to make the component insoluble in water. .

In addition to the above-mentioned components, various kinds of surfactants, preservatives, dispersants, defoamers, thickeners, inorganic and organic pigments may be appropriately added to the base paint of the present invention.

The coating amount of the base paint of the present invention may be appropriately adjusted depending on the unevenness of the wood material panel used as the base material, but is usually 50 to 300 g / m ² . Further, the coating amount of the above-mentioned release coating material for concrete mold applied on it is relatively small, and usually 30 to 1
It is 50 g / m ² .

[0027]

EXAMPLES The present invention will now be described with reference to examples, but the present invention is not limited thereto.

Base coating 1 Polyvinyl alcohol (PVA21 manufactured by Kuraray Co., Ltd.)
30 parts by weight of a 10% aqueous solution of 7), 30 parts by weight of an aqueous emulsion (DL612, manufactured by Asahi Kasei Kogyo Co., Ltd.), and 40 parts by weight of calcium carbonate (manufactured by Bihoku Powder Chemical Co., Ltd., Softon 1200) as a filler, and colored. 0.2 part of carbon black as an agent was added and mixed well, and further, as a cross-linking agent, polymeric diphenylmethane diisocyanate (manufactured by Mitsui Toatsu Chemicals, Cosmonate M).
-100) 4 parts by weight added and mixed to give a gray base paint 1
Was adjusted.

Base coating 2 Instead of the polyvinyl alcohol used in Base coating 1, acetoacetylated polyvinyl alcohol (Z-200 manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) was used,
Gray base paint 2 was prepared with the same composition.

Synthesis Example 1 200 g of dimethylpolysiloxane having a molecular weight of 2000 and hydroxyl groups at both ends (KF-6001 manufactured by Shin-Etsu Silicon Co., Ltd.) and 400 g of polypropylene glycol having a molecular weight of 2000 were placed in a 1-liter four-necked flask. 300 g of diphenylmethane diisocyanate (Sumijour 44S manufactured by Sumitomo Bayer Urethane Co., Ltd.) was added and reacted at 110 ° C. for 3 hours to obtain a silicon-modified urethane prepolymer having a free NCO group content of 8.3%. This is designated as Compound 1. The dimethylpolysiloxane content was 22%, and the equivalent of the polyisocyanate compound was 4 with respect to 1 equivalent of the polyols.

Synthesis Example 2 200 g of KF-6001 was placed in a 1-liter four-necked flask, and polymeric diphenylmethane diisocyanate (Cosmonate M-10, manufactured by Mitsui Toatsu Chemicals, Inc.) was used.
540 g of 0) was added and reacted at 100 ° C. for 3 hours to obtain a silicon-modified urethane prepolymer having a free NCO group content of 22%. This is designated as Compound 2. The dimethylpolysiloxane content was 27%, and the equivalent of the polyisocyanate compound was 20 with respect to 1 equivalent of the reactive silicon.

Comparative Example 1 Cosmonate M-100 was used as the main component, and tetrachloro-4,4'-diaminodiphenylmethane (Iharacuamine TCDA manufactured by Ihara Chemical Industry Co., Ltd.) was used as the curing agent.
M) and polycaprolactone polyol (manufactured by Daicel Chemical Industries, Ltd., Praxel 305, molecular weight 830, trifunctional) are used in combination, pigment paste (manufactured by Toyo Ink Mfg. Co., Ltd., TUR-9300, gray), antifoaming agent (Nippon Kagaku) Komyo Co., Ltd., Zeolym A-5) was blended, and a mold release paint was further formulated in which a high boiling point plasticizer (Dohachi Chemical Co., Ltd., DOP, boiling point 390 [deg.] C.) was blended in order to provide mold releasability. .

The weight ratio of the main agent and the curing agent is 100/150.
In proportions of, a base paint 1 concrete was 120 g / m ² coating - was coated at a rate of 100 g / m ² on preparative frame plywood, to obtain a gray concrete formwork for coated panel of Comparative Example 1 .

Comparative Example 2 Cosmonate M-100 was used as the main component, and the curing agent was a propylene oxide adduct of ethylenediamine (Adeka Polyether EDP-450 manufactured by Asahi Denka Co., Ltd.) and a propylene oxide adduct of bisphenol A ( Asahi Denka Kogyo Co., Ltd., ADEKA POLYOL BPX-33) was used, TUR-9300 was used as a pigment paste, Zeolime A-5 was used as an antifoaming agent, and Shirin oil (Toray Silicon Co., Ltd. Company made, S
A conventional release coating composition containing H-200 (350) was formulated.

The weight ratio of the main agent and the curing agent is 100/100.
Was applied in a proportion of 100 g / m ² on a concrete formwork plywood coated with 120 g / m ^{2 of} base paint 1 to obtain a gray painted panel for concrete formwork of Comparative Example 2. .

Example 1 Cosmonate M-100 was used as the main component, and ED was used as the curing agent.
P-450, BPX-33 and KF-6001 as a reactive silicone having hydroxyl groups at both ends were mixed with TUR-9300 as a pigment paste and Zeolime A-5 as a foaming inhibitor, and the mold release of the present invention was performed. The paint was formulated.

The weight ratio of the main agent and the curing agent is 100/100.
And the base paint 1 was applied at a rate of 100 g / m ² on a concrete formwork plywood coated with 120 g / m ² to obtain a gray concrete formwork coated panel of Example 1. .

Example 2 Cosmonate M-100 was used as the main component, EDP-450 as a polyol, Praxel 305 and TCDAM as an amine were used in combination as a curing agent, and reactive silicones having hydroxyl groups at both ends (Japan Unicar Co. Company made, FZ-
3722), TUR-9300 as a pigment paste, and Zeorime A-5 as a foaming inhibitor were blended to formulate the release coating material of the present invention.

The weight ratio of the main agent and the curing agent is 100/150.
Was applied in a proportion of 100 g / m ² on a concrete formwork plywood coated with 120 g / m ^{2 of} base paint 2 to obtain a gray painted panel for concrete formwork of Example 2. .

[0040] Using the silicone-modified urethane prepolymer in Synthesis Example 1 to Example 3 the base resin, as concrete an underlying coating 1 was 120 g / m ² coating - on the preparative frame plywood, 100 g / m ² was applied, in the air It was cured by the moisture of No. 3 to obtain a coated panel for concrete formwork of Example 3.

Example 4 The silicone-modified urethane prepolymer of Synthesis Example 2 was used as the main agent, a mixture of EDP-450 and Praxel 305 as the polyol was used as the curing agent, and KF-6 was used as the reactive silicone.
001 together with TUR-930 as a pigment paste
0, Zeolime A-5 was added as an antifoaming agent, and the release coating composition of the present invention was formulated.

The main agent and the curing agent are mixed in a weight ratio of 100/75, and the base paint 2 is applied at a rate of 100 g / m ² on a concrete form plywood coated with 120 g / m ² . A gray painted panel for concrete formwork of Example 4 was obtained.

The results of measuring the performance of these coated panels for concrete formwork are shown in the table. The performance was evaluated by the following concrete repeated casting test. The number of times of diversion before the mold and the concrete became difficult to release due to insufficient curing of the concrete or remarkable cracks on the coated surface was measured.

Further, the formwork-coated panel was left for 15 days at 40 ° C. and 80% humidity before conducting this test. This is because long-term outdoor exposure was assumed, and it is easier to make a difference when the test was performed after the coated surface was deteriorated to some extent.

Repeated casting test of concrete A cement paste consisting of 100 parts of Portland cement and 33 parts of water was poured into a form painting panel of 303 mm × 303 mm × 60 mm and sealed with a vinyl bag or the like. After accelerated curing curing at 50 ° C. for 24 hours, it was disassembled and this was repeated.

[0046]

[Table 1]

[0047]

As shown in each of the above embodiments, the coated panel for concrete formwork coated with the release coating material of the present invention is
Easy to release from hardened concrete, and 2
Releasability (peelability) which was the same as the first time was obtained even when the composition was repeatedly placed 0 times or more. Moreover, it has brought a remarkable technological advancement that a smooth and glossy concrete surface can be obtained.

Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI Technical display area E04G 19/00

Claims (9)

[Claims] 1. A mold-releasing paint for concrete molds, which comprises a silicone-modified urethane resin as a main component and has mold-releasing properties for a long period of time. 2. A silicon-modified urethane resin modified with an organic silicon (A, hereinafter referred to as reactive silicon) containing two or more hydroxyl groups at the end or side chain of dimethylpolysiloxane or at the end and side chain is the main component. A mold-releasing paint for concrete formwork that has mold releasability over a long period of time. 3. An organic polyisocyanate compound (B, containing reactive silicon (A) and two or more isocyanate groups)
Hereinafter, a mold release paint for concrete formwork, which has a long-term mold release property obtained by a reaction with a polyisocyanate compound). 4. An isocyanate group-terminated silicone-modified urethane prepolymer (C) obtained by the reaction of reactive silicone (A) with an excess of polyisocyanate compound (B) in an equivalent ratio, and polyol (D) / or amine ( F) / or a mold release coating material for concrete molds, which has a long-term mold release property obtained by a reaction with reactive silicon (A). 5. An isocyanate group-terminated silicon-modified urethane prepolymer (C) obtained by reacting a reactive silicone (A) with an excess amount of a polyisocyanate compound (B) in an equivalent ratio for a long period of time obtained by moisture curing. Mold release paint for concrete formwork with mold releasability. 6. The reactive silicon (A) content is 2 to 40% (by weight), which is fixed in the coating material by a urethane bond and does not migrate to the surface and exude. A mold-releasing paint for concrete formwork, which has mold-releasing properties for a long time of 2, 3, 4, and 5. 7. The content of the reactive silicon (A) is preferably 5 to 25% (by weight), is fixed in the paint by a urethane bond, and does not migrate to the surface and exude. Item 1, 2, 3, 4, 5, mold release paint for concrete formwork, which has mold releasability over a long period of time. 8. An aqueous solution (F) containing a water-soluble polymer and / or an aqueous liquid (G) containing an aqueous emulsion as a main component.
And filler (H) and polyisocyanate compound (B)
A release coating composition according to any one of claims 1, 2, 3, 4, 5, 6, and 7 is applied to a wood material panel as a base coating, and then the release coating composition is applied. Paint panel for frame. 9. The concrete mold according to claim 8, wherein the aqueous solution (F) and / or the aqueous emulsion (G) containing a water-soluble polymer has an acetoacetyl group in the molecule. Painted panel.