JPH06190822A - Lightweight aerated concrete, manufacture thereof and powder coating for reinforcing steel frame - Google Patents

Abstract

PURPOSE:To obtain lightweight aerated concrete, in which the adhesion between reinforcing steel frame and coating film and between the coating film and lightweight concrete is small and the crack and peeling of coating film due to the strain and the like of the lightweight concrete material and the peeling between the coating film and the lightweight concrete material scarcely occur. CONSTITUTION:The lightweight aerated concrete concerned is made of formed matter, which is obtained by autoclave-curing reinforcing steel frame, onto with thermosetting epoxy resin-based powder coating is applied and which is baked at the temperature higher than the melting point of the powder coating so as to realize the gel content of 10-80wt.%, under the condition being put into lightweight aerated concrete component.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing lightweight cellular concrete using a reinforcing steel frame and a powder coating composition for coating the reinforcing steel frame.

[0002]

2. Description of the Related Art Generally, aerated concrete cured by autoclave is neutralized immediately after its production. Further, carbon dioxide in the air carbonizes the concrete, further reducing the rust preventive effect. This carbonation causes corrosion of the steel frame inside the concrete, and therefore, in order to prevent the steel frame from rusting over time, it has been practiced to apply a rust preventive coating to the steel frame and embed it in aerated concrete.

In order to enhance the rust-preventing effect, a rust-preventing treated steel frame has been conventionally used in which a cement-based coating agent consisting of a mixture of cement, silica sand and water is dipped and hardened on a reinforcing steel frame to be hardened. Further, JP-A-3-109247 discloses that hydrotalum is added to 100 parts by weight of a film forming component composed of 60 to 95% by weight of a phenoxy resin and 5 to 40% by weight of a curing agent having a blocked isocyanate group. To produce a rust-prevented steel frame by coating a light-weight cellular concrete reinforced steel frame resin composition containing 0.01 to 10 parts by weight of a rust preventive agent composed of a site compound, zinc white, and zinc chromate, and curing the resin composition by heating. Is proposed.

On the other hand, in Japanese Patent Laid-Open No. 3-170358, a coating film comprising a phenoxy resin of more than 95% by weight and 100% by weight or less and a blocked isocyanate group-containing curing agent of less than 5% by weight to 0% by weight is formed. A lightweight cellular concrete reinforced steel frame resin composition containing 0.01 to 10 parts by weight of a rust preventive pigment composed of a hydrotalcite compound, zinc white, and zinc chromate is applied to 100 parts by weight of the component, and the composition is protected by heating. It is described to make rust treated steel.

Further, Japanese Patent Application Laid-Open No. 3-96555 discloses that
Anti-corrosion coating of rebar, characterized by preheating the rebar to a temperature at which the powder does not melt, applying the powder coating, and then placing it in the concrete component and secondarily adhering to both the rebar and concrete by autoclave curing. The method is described.

Further, Japanese Patent Publication No. 62-57667 discloses that
(A) Number average molecular weight 7 obtained by reacting bis (4-hydroxyphenyl) alkane with epichlorohydrin
00 to 4000 and an epoxy equivalent of 150 to 3800
Epoxy resin, (B) a condensation product of a novolac-type phenol resin and epihalohydrin, (C) a rubber-like substance having a reactive functional group containing butadiene as a main component, and (D) a phenol resin as a main component. 5 to 50 parts by weight of the component (B) per 100 parts by weight of the component (A).
By weight, the component (C) is 1 to 50 parts by weight, and the component (D) is 0.6 parts by weight of a phenolic hydroxyl group per equivalent of the total epoxy groups contained in the components (A), (B) and (C). ~
A powder coating composition is described, characterized in that it consists of a ratio of 1.5 equivalents.

[0007]

Among such conventional products, the one using the cement-based coating agent has insufficient adhesion between the lightweight cellular concrete component and the cement-based coating agent applied to the steel frame. There is a brittleness in the coating of the cement-based coating agent applied to the steel frame. Therefore, due to vibration during transportation of building materials made of lightweight aerated concrete reinforced with rustproof steel, vibration at the time of building a house using these lightweight aerated concrete materials, or vibration due to an earthquake, etc. When there is distortion,
The rustproof steel frame and the lightweight cellular concrete separate at the interface. Therefore, there is a problem that the cement-based coating agent is cracked and rust is generated in the steel frame, and the steel frame is eroded.

Further, in the composition for light-weight cellular concrete-reinforced steel frame disclosed in JP-A-3-109247, the blocked isocyanate groups are dissociated at 100 ° C. to 220 ° C. to form a sufficiently cured coating film on the reinforcing steel frame. After being placed in the lightweight cellular concrete component, it is usually placed in an autoclave for 18
Since a lightweight cellular concrete reinforced with a reinforcing steel frame is produced by curing at 0 ° C. ± 20 ° C. and 10 ± 2 atmospheric pressure for 8 to 12 hours, the adhesion between the coating film on the reinforcing steel frame and the lightweight cellular concrete component does not occur. It was sufficient, and there was a problem of peeling during this period.

In the case of the lightweight cellular concrete reinforced steel frame composition disclosed in Japanese Patent Application Laid-Open No. 3-170358, a coating applied on the reinforced steel frame has an insufficient three-dimensional network structure, and a cement-based coating agent is used. Similarly, when the lightweight cellular concrete material is distorted, the coating layer is destroyed, peeling occurs between the reinforcing steel frame and the coating film, rust occurs on the reinforcing steel frame, and the steel frame is eroded. there were.

On the other hand, the rust-preventive coating for reinforcing bars of Japanese Unexamined Patent Publication No. 3-96555, in which the reinforcing bars are preheated to a temperature at which the powder does not melt, a powder coating is applied, and then placed in a concrete component for autoclave curing. In the method, since the powder coating material adhered on the reinforcing bar is not melted, it exists on the reinforcing bar in the form of particles, does not form a continuous film, and has many voids reaching the reinforcing bar. For this reason, when it is put into the concrete component, the concrete component permeates through the voids and directly contacts the reinforcing bar, so that there is a problem that rust is generated from this part and the reinforcing bar is eroded.

The powder coating composition disclosed in Japanese Patent Publication No. 62-57667 is applied when a lightweight cellular concrete is produced after the reinforcing steel frame is coated and sufficiently baked, and the coating film is excessively baked due to autoclave curing. There is a problem that the film becomes hard, the adhesion between the coating film on the reinforcing steel frame and the lightweight cellular concrete component becomes insufficient, and peeling occurs during this period.

When a thermosetting acrylic resin-based powder coating is used, the adhesion to the reinforcing steel frame is poor and there is a problem in rust prevention. Therefore, thermosetting polyester resin-based or thermosetting epoxy resin / When using an acid or acid anhydride as a curing agent in polyester resin powder coatings and epoxy resin powder coatings, the coating film decomposes due to hydrolysis during autoclave curing, and There is a drawback that a uniform coating film is not formed between them, rust is generated from the reinforcing steel frame, and the steel frame is eroded.

The object of the present invention is to solve the problems of the conventional products as described above, and to have a high adhesion between the reinforcing steel frame and the coating film, and the coating film and the lightweight concrete, and the coating film due to the strain of the lightweight cellular concrete material. It is an object of the present invention to provide a lightweight cellular concrete capable of preventing cracking and delamination of the coating, delamination between a coating film and a lightweight cellular concrete material, a method for producing the same, and a powder coating material for a reinforcing steel frame.

[0014]

The present invention provides the following lightweight cellular concrete, a method for producing the same, and a powder coating for reinforcing steel frame. (1) Autoclave in which a reinforcing steel frame coated with a thermosetting epoxy resin powder coating material and baked to a gel content of 10 to 80% by weight at a temperature above the melting point is put in a lightweight cellular concrete component. Light-weight cellular concrete characterized by consisting of a cured molding. (2) A thermosetting epoxy resin powder coating is applied to the reinforcing steel frame, baked at a temperature above the melting point so that the gel content is 10 to 80% by weight, and then put into a lightweight cellular concrete component,
A method for producing a lightweight cellular concrete, which is characterized by curing in an autoclave. (3) 60 to 80 parts by weight of bisphenol A type epoxy resin having an epoxy equivalent of 450 to 3300 g / eq, 5 to 15 parts by weight of phenol novolac type epoxy resin having an epoxy equivalent of 150 to 800 g / eq, and 2 to 6 meq / g of phenolic hydroxyl group. And a resin component 100 consisting of 15 to 35 parts by weight of a phenol resin having a softening point of 70 to 120 ° C.
The powder coating material for reinforcing steel frame of lightweight cellular concrete according to (1) above, which is composed of a thermosetting epoxy resin powder coating material containing 40 to 120 parts by weight of a pigment component with respect to parts by weight. (4) Pigment based on 100 parts by weight of a resin component consisting of 80 to 98 parts by weight of a bisphenol A type epoxy resin having an epoxy equivalent of 450 to 3300 g / eq and 2 to 20 parts by weight of an amino compound having an active hydrogen equivalent of 20 to 300 g / eq. Minutes 4
The powder coating material for reinforcing steel frame of lightweight cellular concrete according to (1) above, which comprises a thermosetting epoxy resin powder coating material in an amount of 0 to 120 parts by weight.

In the present invention, the bisphenol A type epoxy resin used in the thermosetting epoxy resin-based powder coating as the powder coating for reinforcing steel frame has an epoxy equivalent of 450 to 3
300 g / eq, preferably 600-2000 g / eq
Which are manufactured by Yuka Shell Epoxy Co., Ltd., for example, Epicoat 1002, Epicoat 1003, and Epicoat 1
004, Epicoat 1005, Epicoat 1007 (all are trade names), Ciba-Geigy Co., Ltd. Araldite 6084 (trade name), Dow Chemical Japan Co., Ltd. DER-663, DER-667 (all trade names), etc. Is used.

The phenol novolac type epoxy resin has an epoxy equivalent of 150 to 800 g / eq, preferably 1
60 to 500 g / eq, for example, Epicoat 152, Epicoat 15 manufactured by Yuka Shell Epoxy Co., Ltd.
4 (both are trade names), Toto Kasei Co., Ltd. Epotote YDPN-601, Epotote YDPN-602 (both are trade names) and the like.

The phenol resin has a phenolic hydroxyl group of 2 to 6 meq / g, preferably 2.5 to 5.0 eq.
/ G, softening point 70 to 120 ° C, preferably 80 to 100
C., for example, Epicure 170, Epicure 171, Epicure 17 manufactured by Yuka Shell Epoxy Co., Ltd.
1N, Epicure 172 (all are trade names), XD-8062.00 (trade name) manufactured by Dow Chemical Japan Co., Ltd., and the like.

The amino compound has an active hydrogen equivalent of 20 to 300.
g / eq, preferably 20 to 200 g / eq, such as dicyandiamide and its derivative, imidazole and its derivative, aromatic amine and its derivative, aliphatic amine and its derivative, hydantoin and its derivative, active hydrogen by heating. And a latent amino compound that generates

Examples of the pigment include coloring pigments such as titanium dioxide, red iron oxide, yellow iron oxide, inorganic pigments such as carbon black, extrinsic pigments such as talc, barium sulfate, silica, calcium carbonate, alumina and clay, aluminum tripolyphosphate and zinc. Examples include rust preventive pigments such as chromate, strontium chromate, zinc phosphate and zinc borate.

The powder coating for reinforcing steel frame according to claim 3 of the present invention comprises 60 to 80 parts by weight, preferably 60 to 75 parts by weight, of the above bisphenol A type epoxy resin, 5 to 15 parts by weight of phenol novolac type epoxy resin, preferably 5-13
40 parts by weight, preferably 45 parts by weight of pigment, based on 100 parts by weight of the resin component consisting of 15 parts by weight and 15 to 35 parts by weight of phenol resin, preferably 17 to 30 parts by weight.
~ 110 parts by weight.

In this powder coating, bisphenol A
When the epoxy equivalent of the type epoxy resin is less than 450 g / eq, it becomes liquid and does not become powder coating, and 3300 g
If it exceeds / eq, crosslinking becomes insufficient and the coating film becomes soft, which is not preferable. Further, when the amount is less than 60 parts by weight, the coating film is too crosslinked to make the coating film hard and brittle, and when it exceeds 80 parts by weight, the coating film becomes too soft and the coating film becomes too soft. .

When the epoxy equivalent of the phenol novolac type epoxy resin is less than 150 g / eq, or when the blending amount exceeds 15 parts by weight, the coating becomes too hard to form a hard and brittle coating, and the epoxy equivalent is 800 g / eq. If the amount exceeds 5 or the amount is less than 5, the coating film becomes too soft due to insufficient crosslinking, which is not preferable.

When the phenolic hydroxyl group of the phenol resin is less than 2 meq / g, or the compounding amount is 15
When the amount is less than the above, the cured coating film becomes too soft due to insufficient crosslinking, and when the phenolic hydroxyl group exceeds 6 meq / g, or when the compounding amount exceeds 35 parts by weight, the coating film is too crosslinked and hard and brittle. Both are not preferable. If the softening point of the phenolic resin is less than 70 ° C, the powder coating material tends to be blocked,
If the temperature exceeds 0 ° C, it is difficult to uniformly mix with other components during melt-kneading in the production of powder coating, which is not preferable.

The pigment content is 4 with respect to 100 parts by weight of the resin component.
If the amount is less than 0 part by weight, fine irregularities are hardly formed on the coating film, and the compatibility with the inorganic concrete component is poor.
On the other hand, if it exceeds 120 parts by weight, the amount of the pigment is too much and the curing is insufficient, resulting in a brittle coating film, which is not preferable.

The powder coating for reinforcing steel frame according to claim 4 of the present invention is 80 to 98 parts by weight, preferably 85 to 96 parts by weight, and 2 to 20 parts by weight, preferably 4 of the bisphenol A type epoxy resin. The pigment component is contained in an amount of 40 to 120 parts by weight, preferably 45 to 110 parts by weight, based on 100 parts by weight of the resin component of 16 parts by weight.

In this powder coating, bisphenol A
When the epoxy equivalent of the type epoxy resin is less than 450 g / eq, it becomes liquid and does not become powder coating, and 3300 g
If it exceeds / eq, crosslinking is insufficient and a soft coating film is formed, which is not preferable. If the blending amount is less than 80 parts by weight, the coating film becomes too hard to be hard and brittle,
If it exceeds 98 parts by weight, crosslinking is insufficient and the coating film becomes too soft, which is not preferable.

The active hydrogen equivalent of the amino compound is 20 g / e.
When it is less than q, or when the blending amount exceeds 20 parts by weight, it becomes a crosslinked and hard and brittle coating film, and when the active hydrogen equivalent exceeds 300 g / eq or when the blending amount is less than 2 parts by weight. In addition, the crosslinking becomes insufficient and the coating film becomes too soft, which is not preferable.

The pigment content is 4 with respect to 100 parts by weight of the resin component.
If the amount is less than 0 part by weight, fine irregularities are hardly formed on the coating film, and the compatibility with the inorganic concrete component is poor.
On the other hand, if it exceeds 120 parts by weight, the pigment will be too much and the curing will be insufficient, resulting in a brittle coating film. In the present invention, a pigment dispersant, a surface conditioner, an antifoaming agent, a heat resistance stabilizer, a catalyst and the like can be appropriately added as needed.

The above powder coating composition of the present invention can be obtained by sufficiently kneading the respective compositions at about 80 to 120 ° C., cooling and pulverizing them. As the melt-kneading device, a heating roll, a heating kneader, an extruder, and other devices are used. The powdering can also be carried out by a so-called spray drying method in which each of these components is dissolved in a volatile solvent and sprayed in hot air to give a powder.

In the lightweight cellular concrete according to claim 1 of the present invention, the thermosetting epoxy resin-based powder coating material obtained as described above is coated on the reinforcing steel frame, and then the gel content at the temperature above the melting point of the powder is obtained. After baking to 10 to 80% by weight,
It is a lightweight cellular concrete composed of a molded product that is put into a lightweight cellular concrete component and subjected to autoclave curing.

In the method for producing a lightweight cellular concrete according to claim 2 of the present invention, when the reinforcing steel frame is put into the lightweight cellular concrete component and is molded by autoclave curing under high temperature, high pressure and strong alkaline conditions, the reinforcing steel frame is strongly alkaline. The thermosetting epoxy resin-based powder coating that does not cause corrosion of the coating or decomposition of the coating film is uniformly applied to the reinforcing steel frame by powder electrostatic coating method, fluidized dipping method, etc., and baked at a temperature above the melting point to form a gel. After forming a uniform film with a content of 10 to 80% by weight, put it in the lightweight cellular concrete component and carry out autoclave curing to cause the lightweight cellular concrete component to bite into the coating under high temperature and high pressure. Improves the adhesion between the steel coating and lightweight cellular concrete, and at the same time crosslinks the coating to give it a three-dimensional network structure.
It strengthens the coating film and also improves the adhesion to the reinforcing steel frame.

The baking condition of the powder coating applied to the reinforcing steel frame is generally 120 to 200 ° C., preferably 130.
˜180 ° C. for 2 to 30 minutes, preferably 3 to 20 minutes and a gel content of 10 to 80% by weight, preferably 20.
˜70% by weight.

In the present invention, the gel content means an organic solvent (eg, tetrahydrofuran) as a curing component in the coating film.
It is the content of insoluble matter, and is shown as 0% by weight for uncured and 100% by weight for fully cured.

In the present invention, when the gel content of the coating film is less than 10% by weight, during the autoclave curing, the amount of the light-weight cellular concrete component is too large to bite into the coating film, and some parts reach the reinforcing steel frame. Rust occurs on the reinforcing steel frame. On the other hand, when the gel content exceeds 80% by weight, the lightweight cellular concrete component is too little bited into the coating film during autoclave curing, and the adhesion between the coating film and the lightweight cellular concrete component decreases.

In the present invention, as the lightweight cellular concrete component, those conventionally used can be used, for example, cement 40 to 60 parts by weight, silica sand 40 to 60 parts by weight, foaming agent 0.1 to 3.0 parts by weight. The part is generally used, but other aggregates or the like may be added. The amount of water added to the lightweight concrete component may be the same as conventional.

The autoclave curing conditions for the lightweight cellular concrete may be the same as those in the conventional one, for example, 150 to 220 ° C.
It is preferably 160 to 200 ° C., 5 to 15 atm, preferably 8 to 12 atm for 5 to 20 hours, preferably 8 to 12
Time cure.

[0037]

EXAMPLES Next, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the technical scope of the present invention is not limited to these Examples. In addition, the compounding part number of each component in an Example and a comparative example shows a weight part.

Examples 1 to 9 and Comparative Examples 1 to 5 All components of the compositions of Examples 1 to 9 and Comparative Examples 1 to 5 shown in Tables 1 to 3 were made into a dry blender (manufactured by Mitsui Kakoki Co., Ltd., The mixture was uniformly mixed for about 1 minute by a Henschel mixer (trade name), and then melt-kneaded under a temperature condition of 80 to 100 ° C. by using an extrusion kneader (trade name: Busconieder PR-46, manufactured by Bus Co.). Next, the mixture was cooled to 15 ° C., finely pulverized with a hammer-type impact pulverizer, and then filtered through a 150-mesh wire net to obtain each powder coating material.

The powder coating thus obtained was reinforced with a steel frame (0.37 m
m × 50 mm × 100 mm) by electrostatic coating and baking under the melting and heating conditions shown in Table 4 to obtain a coating film thickness of 5
A reinforced steel frame having a continuous film of 0 μm on its surface was obtained. The gel content of each continuous film is shown in Table 4.

Ten pieces of each of the obtained reinforcing steel frames were fixed to a lightweight cellular concrete molding form, and cement 50 was added.
Part, 50 parts of silica sand, 50 parts of water, and 0.3 parts of aluminum paste (trade name SAP-720N Showa Aluminum Co., Ltd.) are mixed and poured into a mold. Let stand for 30 minutes, remove the formwork and put in an autoclave for 180 minutes.
By reacting at 8 ° C. and 10 atm for 8 hours, a lightweight cellular concrete reinforced with a reinforcing steel frame coated with a thermosetting epoxy resin-based powder coating film was obtained. Table 5 shows the performance test results of the obtained lightweight cellular concrete.

Comparative Examples 6 to 7 The powder coating materials used in Example 1 were used, and each is shown in Table 4.
Baking was performed under the melting and heating conditions shown in (1) to obtain a reinforcing steel frame having a continuous film with a coating film thickness of 50 μm on the surface. The respective gel contents are shown in Table 4. Ten lightweight reinforcing steel frames were obtained in the same manner as in Example 1 to obtain lightweight cellular concrete reinforced with the reinforcing steel frames. Table 5 shows the performance test results of the obtained lightweight cellular concrete.

Comparative Example 8 A reinforcing steel frame was preheated to 100 ° C. and electrostatically coated with the powder coating used in Example 1 to obtain a reinforcing steel frame in which powder was simply adhered without being melted. . The gel content of the applied paint was 0%. In the same manner as in Example 1, ten obtained reinforcing steel frames were obtained to obtain lightweight cellular concrete reinforced with the reinforcing steel frames. Table 6 shows the performance test results of the obtained lightweight cellular concrete.

[0043]

[Table 1]

[0044]

[Table 2]

[0045]

[Table 3]

Note 1 in Tables 1 to 3) Trade name: Yuka Shell Epoxy Co., Ltd. Bisphenol A type epoxy resin Epoxy equivalent 600-700
g / eq number average molecular weight 1060, softening point 78 ° C. 2) Trade name Yuka Shell Epoxy Co., Ltd., bisphenol A type epoxy resin, epoxy equivalent 950 to 105
0 g / eq number average molecular weight 1900, softening point 109 ° C. 3) Trade name, manufactured by Nippon Ciba Geigy Co., Ltd. Bisphenol A type epoxy resin Epoxy equivalent 900-1000 g
/ Eq number average molecular weight 875-975 softening point 100 ° C 4) Trade name Dow Chemical Japan Co., Ltd. bisphenol A type epoxy resin epoxy equivalent 1600-2000
g / eq number average molecular weight 3600, softening point 123 ° C. 5) Trade name Yuka Shell Epoxy Co., Ltd. Phenol novolac type epoxy resin Epoxy equivalent 176-1
80 g / eq semi-solid type (normal temperature) 6) Trade name Toto Kasei Co., Ltd. Phenol novolac type epoxy resin Epoxy equivalent 180-220 g / e
q Softening point 60 ° C. 7) Trade name Yuka Shell Epoxy Co., Ltd. Phenolic resin Phenolic hydroxyl group 3.5 to 5.0 m
eq / g Softening point 80 ° C 8) Brand name Yuka Shell Epoxy Co., Ltd. Phenolic resin Phenolic hydroxyl group 2.5 to 3.5 m
eq / g Softening point 90 ° C. 9) Added as catalyst. 10) Product name Ajinomoto Co., Inc. 1,3-bis (hydrazinocarboethyl) -5-isopropylhydantoin
Active hydrogen equivalent 78.5 g / eq, melting point 122 ° C. 11) Trade name, manufactured by Teika Co., Ltd. Anticorrosion pigment, aluminum tripolyphosphate 12) Trade name, manufactured by Monsanto

[0047]

[Table 4]

[0048]

[Table 5]

Note 1 in Table 5) Destructiveness: “Cracks” in the obtained lightweight cellular concrete
Visually determine if there is. 2) Adhesion: Lightweight concrete is hit with a hammer once to break. The state of adhesion of the lightweight cellular concrete component to the steel frame is visually judged according to the following criteria. Good; when there is no peeling of the coating film from the steel frame and the lightweight cellular concrete component adheres to the steel frame without any gaps. Poor: When the coating film peels from the steel frame or the lightweight cellular concrete component is hardly attached to the steel frame. 3) Heat-resistant cold cycle testability: The obtained lightweight cellular concrete is dried at a humidity of 98% or more at a temperature of 50 ° C. for 24 hours, and −1.
One cycle of standing at 0 ° C for 24 hours is 100
Concrete “cracking” and “peeling” after the cycle
Visually determine if there is. 4) Rust resistance: A test piece in which lightweight cellular concrete with a thickness of 3 mm was left on the steel frame was used as a salt spray test device “JISK5400”.
-9.1 (1990) "and left for 4000 hours, then the light bone concrete component is removed and examined for rust. Good: No rust, Poor: There is rust.

As is clear from the above results, Example 1
In any of the performances shown in ~ 9, the lightweight concrete is not destroyed in any case, the coating film on the steel frame and the concrete component adhere well, and cracks and peeling do not occur even under severe temperature changes. It shows that it does not occur, and that it is very excellent in rust prevention.

On the other hand, Comparative Example 1 in which the phenol resin exceeds 35 parts by weight, Comparative Example 2 in which the pigment content exceeds 120 parts by weight and the phenol resin is less than 15 parts by weight, and Comparison in which the pigment content is less than 40 parts by weight Example 3, Comparative Example 4 in which the amino compound is less than 2 parts by weight, Comparative Example 5 in which the amino compound exceeds 20 parts by weight, and Comparative Example 7 in which the gel content of the coating film exceeds 80% by weight are all adhesive, heat-resistant cold cycle. Comparative example 6 in which the testability is poor and the gel content of the coating film is less than 10% by weight, JP-A-3-96.
Comparative Example 8 according to the invention of Japanese Patent No. 555 shows that the rust resistance is inferior.

[0052]

EFFECTS OF THE INVENTION According to the present invention, strong adhesion can be obtained in both the coating layer and the reinforcing steel frame and the concrete layer, and the powder coating layer itself is cured to obtain mechanical strength,
It becomes excellent in corrosion resistance, and it is possible to obtain a lightweight cellular concrete with little cracking or peeling of the coating film due to strain of the lightweight cellular concrete material, and less peeling between the coating film and the lightweight concrete.

Claims (4)

[Claims] 1. A state in which a reinforcing steel frame coated with a thermosetting epoxy resin-based powder coating material and baked to a gel content of 10 to 80% by weight at a temperature equal to or higher than a melting point is put in a lightweight cellular concrete component. Light-weight cellular concrete, which is composed of a molded product that has been autoclaved in. 2. A reinforcing steel frame is coated with a thermosetting epoxy resin-based powder coating material, baked at a temperature above the melting point so that the gel content is 10 to 80% by weight, and then placed in a lightweight cellular concrete component, and then autoclaved for curing. A method for producing lightweight cellular concrete, comprising: 3. Epoxy equivalent of 450 to 3300 g / eq
60 to 80 parts by weight of bisphenol A type epoxy resin,
Epoxy equivalent: 150 to 800 g / eq, phenolic novolac type epoxy resin: 5 to 15 parts by weight, phenolic hydroxyl group: 2 to 6 meq / g, and softening point: 70 to 12
A thermosetting epoxy resin-based powder coating material containing 40 to 120 parts by weight of a pigment component with respect to 100 parts by weight of a resin component consisting of 15 to 35 parts by weight of a 0 ° C. phenol resin. Powder paint for reinforcing steel frame of the light-weight cellular concrete described. 4. Epoxy equivalent of 450 to 3300 g / eq
80 to 98 parts by weight of bisphenol A type epoxy resin,
Amino compound 2 with active hydrogen equivalent of 20 to 300 g / eq
Reinforcement of lightweight cellular concrete according to claim 1, characterized by comprising a thermosetting epoxy resin-based powder coating material containing 40 to 120 parts by weight of a pigment component with respect to 100 parts by weight of a resin component consisting of 20 parts by weight. Powder coating for steel frames.