JPH08238453A - Corrosion-proof execution method for concrete - Google Patents

Abstract

PURPOSE: To make usable even in a closed space of relatively high humidity and to form a corrosion-proof coat which can stand up to severe environmental load conditions by specifying the structure of an isocyanate component and a polyamine component and the mixing ratio of the components and curing the coating film formed by spraying them. CONSTITUTION: A coating material is composed of an isocyanate component (A) which comprises a partial prepolymer prepared by a method in which organic polyisocyanate or part of the isocyanate groups in the polyisocyanate is reacted with polyol of 200 8000 molecular weight or the mixture of them and a polyamine component (B) comprising 100 pts.wt. of polyoxyalkylene polyamine having average molecular weight of 1000-10,000 and two or more aliphatic amino groups in a molecule and 15-100 pts.wt. of active aromatic diamine, excluding toluene diamine, in which an aromatic group does not have an electron attractive property, and a position adjacent to an amino group has 1-5 C alkyl substituent. The isocyanate component (A) and the polyamine component (B) are mixed in an equivalent ratio of 1/0.7-1/1.5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a concrete anticorrosion construction method.

[0002]

2. Description of the Related Art Structures such as sewage treatment facilities, sewers, and wastewater treatment facilities are often closed structures with poor air circulation and are exposed to an acidic atmosphere, which results in deterioration of function due to deterioration of concrete and environmental damage. May occur. As a countermeasure against this, a method of forming an organic film for anticorrosion on the surface of concrete is taken.

In order to prevent such concrete deterioration, conventionally, room temperature curing resins such as epoxy resin, tar epoxy resin, epoxy resin containing ceramic powder, vinyl ester resin, unsaturated polyester resin, vinyl ester resin containing glass flakes, etc. have been used. Then, a method of forming an anticorrosion organic film is adopted, and high and low corrosive environmental load is dealt with by increasing or decreasing the type of material used and the film thickness to be formed.

However, when anticorrosion construction is carried out using the above resins or the like, since the curing speed of these resins is slow, it often takes a long time until the function is exhibited, which is extremely difficult in construction. It was inconvenient. In addition, when the corrosive environmental load is high, the anticorrosion function is enhanced by increasing the number of coatings or increasing the anticorrosion coating film thickness by sandwiching glass cloth or glass mat etc. In order to obtain a high-thickness anticorrosive film, it is necessary to prevent sagging at the time of application, and it is not possible to apply a film thickness above a certain level, so it is necessary to increase the number of applications to secure the required film thickness. there were. Furthermore, in order to increase the thickness of the anticorrosion coating film by sandwiching glass cloth or glass mat,
It is necessary to finish the coated surface more smoothly, which requires a large number of man-hours for construction, and there is a drawback that the process becomes complicated.

On the other hand, as a coating material for protecting concrete floor surfaces and roof waterproofing, a solvent-free thick film coating technique having a high curing rate has been developed. For example, a polyisocyanate component is prepared by using a two-liquid collision mixing type coating device. And the polyol component,
A method in which a polyol / aromatic polyamine mixed component, a polyamine component, or the like is subjected to collision mixing and coating on a coated surface has come into practical use. However, in this method, in order to enhance the adhesion between the coating surface and the coating film, it is unavoidable to use a solvent-type moisture-curing isocyanate resin or the like,
The work environment was deteriorated by the volatile solvent discharged during the coating work, and this was not sufficient to take advantage of the solvent-free coating material for anticorrosion.

[0006]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above-mentioned present situation, suppresses the discharge of volatile solvents, and can be used even in a closed place of relatively high humidity in which air circulation is poor, and Another object of the present invention is to provide a concrete anticorrosion construction method capable of forming a thick film type anticorrosion coating capable of withstanding high environmental load conditions in a short time.

[0007]

The gist of the present invention is to provide a concrete anticorrosion construction method for forming an anticorrosion film on a surface to be coated, wherein the surface to be coated is a two-component curable water-based pre-coating undercoat film. A cured coating film of an epoxy resin is formed, and then the organic polyisocyanate or a part of the isocyanate groups in the organic polyisocyanate has a molecular weight of 200-
Isocyanate component (A) consisting of a partial prepolymer obtained by reacting with 8000 polyols or a mixture thereof, and a polyoxyalkylene having an average molecular weight of 1,000 to 10,000 and having two or more aliphatic amino groups per molecule. 100 parts by weight of polyamine (a),
And an active aromatic diamine (b) having no electron-withdrawing group in the aromatic nucleus and having an alkyl substituent having 5 or less carbon atoms at a position adjacent to an amino group, excluding toluenediamine
To 100 parts by weight of the polyamine component (B), the equivalent ratio of the amino group in the polyamine component (B) to the isocyanate group in the isocyanate component (A) is
It is applied by a spraying method using a high pressure two-liquid collision mixing type spraying device at a mixing ratio of 1 / 0.7 to 1 / 1.5,
It is to cure. The gist of the present invention is also that the concrete anticorrosion construction method is applied by a spray coating method using a masking method. The present invention is described in detail below.

In the present invention, an undercoat is previously applied and cured on the concrete surface to be coated. As the above-mentioned undercoat, a two-component curing type water-based epoxy resin is preferable in that the solvent released into the air is extremely small. The two-component curing type water-based epoxy resin is not particularly limited as long as it is a two-component curing type water-based epoxy resin usually used as an undercoat, and examples of the epoxy resin include EP122W manufactured by Hoechst Synthesis Co., EP128. , Hoechst Synthetic Co., Ltd. VEP2547, Shell Chemicals Co., Ltd. Epicoat DX235, and the like. Examples of the curing agent include Hoechst Synthetic Co., Ltd. EH623W, Hoechst Synthetic Co., Ltd. VEH2133W, Akzo Nobel Co., Ltd. Epilink DP700, etc. You can

In the present invention, a two-component curing type water-based epoxy resin is previously applied as an undercoat on the surface to be coated and cured, and then an isocyanate component (a component for forming an anticorrosive film) is formed thereon. By using A) and the polyamine component (B), a high-pressure two-liquid collision mixing type spraying device,
Both components are sprayed to apply and cure.

In the present invention, the isocyanate component (A) and the polyamine component (B) are used as components for forming the anticorrosive film. The isocyanate component (A) has a molecular weight of 20 parts of an organic polyisocyanate or a part of isocyanate groups in the organic polyisocyanate.
It is a partial prepolymer obtained by reacting with a polyol of 0 to 8000 or a mixture thereof.

The above-mentioned organic polyisocyanate is not particularly limited, and known polyisocyanates and the like can be used, and examples thereof include aromatic polyisocyanates and aliphatic polyisocyanates. Examples of the aromatic polyisocyanates include liquid diphenylmethane diisocyanate obtained by modifying carbodiimide, a partial prepolymer of diphenylmethane diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, and a mixture thereof ( Hereinafter, this is referred to as "TDI"), diphenylmethane-4,4'-diisocyanate (hereinafter referred to as "MDI"), polymethylene polyphenyl polyisocyanate, carbodiimidated modified products thereof, and buretized modified products thereof. be able to.

Examples of the above-mentioned aliphatic polyisocyanates include dicyclohexylmethane-4,4'-diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, hydrogenated xylylene diisocyanate,
These isocyanurate modified products, carbodiimidated modified products and the like can be mentioned.

In the present invention, the above organic polyisocyanate may be used as it is, or may be heated with the polyol in a nitrogen stream at 70 to 80 ° C. for several hours to react a part of the contained isocyanate groups with the polyol. It can also be used as a partially prepolymer. The polyol is not particularly limited as long as it has a molecular weight of 200 to 8000, and for example, propylene glycol,
Low molecular weight polyols such as dipropylene glycol, tridipropylene glycol, diethylene glycol, 1,3-butylene glycol and 2,3-butylene glycol; polyhydric alcohols such as ethylene glycol, propylene glycol and pentaerythritol, and ethylene oxide and propylene oxide. Examples thereof include polyether polyols obtained by addition-polymerizing one kind or two or more kinds of alkylene oxides. In the present invention,
The organic polyisocyanate and the partial prepolymer may be mixed and used.

The polyamine component (B) does not have an electron-withdrawing group in the aromatic nucleus except polyoxyalkylene polyamine (a) and toluenediamine, and has a carbon number of 5 or less at a position adjacent to an amino group. It is a mixture consisting of an active aromatic diamine (b) having an alkyl substituent. As the polyoxyalkylene polyamine (a), a method of reacting terminal hydroxyl groups of a polyoxyalkylene polyol having at least two hydroxyl groups with ammonia under high temperature and high pressure using a hydrogenation-dehydrogenation catalyst. Those having a molecular weight of 1,000 to 8,000 obtained by can be preferably used.

As the polyoxyalkylene polyamine (a), for example, as polyoxypropylene diamine, Jeffamine D-2000 (Huntsman.
Specialty Chemicals Co., amine equivalent 10
00); as polyoxypropylene triamine, Tech Slim TR-5050 (manufactured by Huntsman Specialty Chemicals, amine equivalent: about 1930), Jeffermin T-403 (Heitzman Specialty.
Amine equivalent of about 160) manufactured by Chemicals, Inc. can be mentioned.

At least a part of the primary amino groups in the polyoxyalkylene polyamine (a) has the general formula CH ₂ ═C (R) —Y (wherein R represents hydrogen or a methyl group). Y represents an electron-withdrawing group.) A modified polyoxyalkylene polyamine, which is secondaryized by a Michael addition reaction with an unsaturated hydrocarbon compound represented by the formula, can also be preferably used. Examples of the electron withdrawing group represented by Y include an ester residue, a ketone residue, a cyano residue, a substituted or unsubstituted amide residue, a sulfonic acid residue, and a sulfonic acid ester residue. it can. Examples of the unsaturated hydrocarbon compound include n-butyl acrylate, isobutyl acrylate, t-butyl acrylate, 2-ethylhexyl acrylate, methyl acrylate, lauryl acrylate, stearyl acrylate and propyl acrylate. Acrylic esters; n-butyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, 2-ethylhexyl methacrylate, methyl methacrylate, lauryl methacrylate, stearyl methacrylate, methacrylic acid esters such as propyl methacrylate; acrylonitrile. Acrylamide; N, N'-dimethylacrylamide; ethyl vinyl sulfone; methyl vinyl sulfonate, ethyl vinyl sulfonate and the like.

Examples of the active aromatic diamine (b) having no electron-withdrawing group in the aromatic nucleus and having an alkyl substituent having a carbon number of 5 or less at the position adjacent to the amino group, excluding the above-mentioned toluene diamine, include: , 1,3-dimethyl-2,4-
Diaminobenzene, 1,3-diethyl-2,4-diaminobenzene, 1,3-dimethyl-2,6-diaminobenzene, 1,4-diethyl-2,5-diaminobenzene,
1,4-diisopropyl-2,5-diaminobenzene,
1,4-dibutyl-2,5-diaminobenzene, 1,
3,5-triethyl-2,4-diaminobenzene, 1,
3,5-triethyl-2,6-diaminobenzene, 1,
3,5-tripropyl-2,6-diaminobenzene, 1
-Methyl-3,5-diethyl-2,4-diaminobenzene, 1-methyl-3,5-diethyl-2,6-diaminobenzene and the like can be mentioned. These can be used in combination of two or more. In addition, at least a part of the active aromatic diamine (b) having no electron-withdrawing group in the aromatic nucleus and having an alkyl substituent having 5 or less carbon atoms at a position adjacent to the amino group, excluding the above-mentioned toluenediamine A modified polyamine in which the primary amino group of is converted to a secondary polyamine by a Michael addition reaction with the unsaturated hydrocarbon compound can also be preferably used.

In the polyamine component (B), except for polyoxyalkylene polyamine (a) and toluene diamine, the aromatic nucleus does not have an electron-withdrawing group, and the carbon number is 5 or less at a position adjacent to the amino group. The compounding ratio with the active aromatic diamine having an alkyl substituent (b) is 100 parts by weight of the polyoxyalkylene polyamine (a) except for the toluene diamine, and the aromatic nucleus does not contain an electron-withdrawing group, Moreover, the ratio of the active aromatic diamine (b) having an alkyl substituent having 5 or less carbon atoms at a position adjacent to the amino group is 15 to 100 parts by weight. When the compounding ratio is less than 15 parts by weight, the anticorrosion coating formed is extremely soft and has semi-adhesiveness, so that it is inferior in practicality, and when it exceeds 100 parts by weight, the anticorrosion coating formed is extremely hard, and Since it becomes brittle and not practical, it is limited to the above range. It is preferably 20 to 40 parts by weight.

In the present invention, as a component for forming the anticorrosive film, if necessary, a commonly used auxiliary agent such as a plasticizer, a flame retardant, a filler, various stabilizers, and a coloring agent. Can be used.

In the present invention, the above-mentioned isocyanate component (A) and polyamine component (B) are collided and mixed by a high-pressure two-liquid impingement mixing type spraying device, sprayed to be applied and cured to carry out anticorrosion construction. Give. The high-pressure two-liquid collision mixing type spraying device is shown in FIG. 1, for example. In FIG. 1, tanks 110 and 112 containing both components of the coating material used are connected to a high pressure metering device 120 by liquid supply hoses 111 and 111. The liquid feed hoses 111, 111 are provided with drum pumps 115, 11
5 is attached so that both components of the coating material can be pumped. An air hose 113 for driving is connected to the drum pumps 115, 115, and the air hose 113 is connected to an air compressor (not shown). Dry air is sent to the tanks 110 and 112 from an air compressor through an air dryer 114.

The high-pressure metering device 120 is adapted to apply sufficient pressure to each component of the coating material and to deliver it by a predetermined amount. Supply hose 12 for each component
2, 124 are heating hoses 126 and hand hoses 128
And is connected to the mixed coating gun 130 for spraying the coating material. For example, as shown in FIG. 2, the mixed coating gun 130 is provided with a coating agent passage 133 that mixes both components of the coating agent inside and sends out the mixed solution from the tip thereof, and the tip portion thereof is The coating material spray port 142 is opened to the outside. A sliding valve 134 is inserted in the coating material passage 133. When the sliding valve 134 moves backward in the drawing, the components of the coating agent are sent to the coating agent passage 133 and mixed by the walls of the passageway or the collision of liquids, and the like from the coating agent spray port 142. Sent out. As the mixed coating gun for spraying the coating agent, a gun having a mechanical self-cleaning mechanism can easily and efficiently perform the coating work, and the clogging of the coating agent can be effectively prevented. Is preferred, which is preferable.

The above-mentioned high-pressure two-liquid collision mixing type spraying device is not particularly limited. For example, as a proportioning unit, H-2000 manufactured by US Gasmer, H-3500 manufactured by US Gasmer, FF-1600 manufactured by US Gasmer, Toho. Machinery two-component high-pressure discharge mixing machine MODEL H
F-100 etc. can be mentioned. Examples of the mixed coating gun for a high-pressure two-liquid collision mixing type spraying device having a mechanical self-cleaning mechanism include GX-7 gun manufactured by US Gasmer Co., GX-7-400 gun manufactured by US Gasmer Co., and the like. Further, as a device provided with an air cleaning mechanism, there can be mentioned, for example, a Probler gun manufactured by Grasscraft Inc. in the United States.

In the present invention, when the above-mentioned high-pressure two-liquid collision mixing type spraying device is used, the mixing ratio of the isocyanate component (A) and the polyamine component (B) which are both components of the coating agent is the above-mentioned isocyanate. The polyamine component (B) for the isocyanate group in the component (A)
The equivalence ratio of the amino groups therein is a ratio of 1 / 0.7 to 1 / 1.5. The equivalent ratio of the amino groups in the polyamine component (B) to the isocyanate groups in the isocyanate component (A) is less than 1 / 1.5, or 1 /
When it exceeds 0.7, the anticorrosive film is not formed well, and it remains sticky, or even when the anticorrosive film is formed, it is too soft.

In the present invention, when using the high-pressure two-liquid collision mixing type spraying device, the working pressure is 6 to 15
It is preferably Mpa. In the present invention, the above-mentioned isocyanate component (A) and polyamine component (B), which are both components of the coating composition, are added to the anticorrosion coating in a thickness of 0.3 to 1
It is preferable to apply it so as to be 0 mm. If the film thickness is less than 0.3 mm, defects such as pinholes are likely to occur in the formed film, and if it exceeds 10 mm, the amount of resin used increases, which is economically disadvantageous.

In the present invention, when the anti-corrosion construction is carried out by using the above-mentioned high-pressure two-liquid collision mixing type spraying device, the coating area and the masking area are simply and efficiently coated and the finish is good. In order to prevent the coating agent from adhering to the surface to be coated on which the coating agent is formed by spraying the coating agent, adjacent to the coating area where the coating agent is formed to form the coating film. A masking method for providing a masking area, wherein a sticking surface part that can be stuck to and peeled from the surface to be coated and the surface to be coated are kept at a distance larger than the thickness of the coating film, (I) preparing a masking material having an eaves portion that projects outward from the edge of the masking material, the attaching surface portion of the masking material is arranged in the masking region, and the tip of the eaves portion is coated with the coating material. Placed in the landing area Uni the step of attaching the masking material in the coating surface (II), the (I) and (I
It can be applied by a spray coating method using a masking method including I).

The subject of the concrete anticorrosion construction method of the present invention is not particularly limited, but above all, it is suitably applied to concrete surfaces in closed places such as concrete sewage treatment facilities, underground buried sewers, and concrete drainage treatment facilities. can do.

[0027]

The two-component curing type polyurea-based spray material used in the present invention is hardly affected by external environmental humidity in the curing reaction, and the cured resin has excellent chemical resistance such as acid resistance and alkali resistance. Therefore, it is suitable for anticorrosion treatment of wastewater treatment facilities exposed to various waste liquids. In addition, the two-component curing type polyurea-based spray material used in the present invention does not use a solvent and has a very short touch-hardening time of 2 to 70 seconds, so that the material coated on the concrete wall surface does not drip. It can be coated to the required film thickness for anticorrosion. Furthermore, since no solvent is used, especially by combining a two-component curing type aqueous epoxy resin as the undercoat paint,
It is possible to secure the safety of construction work in a closed place.

In the present invention, by using a masking material having a sticking portion and an eaves portion in spray coating, even when a thick coating film is formed using a coating material which cures quickly, It is possible to accurately and easily perform separate coating between the coating area to be attached and the masking area not to be attached.

Further, in the spray coating, by using a two-component mixed spray coating device having a self-cleaning mechanism as the spray coating device, the work of spray coating a thick film with a quick-curing coating can be facilitated. Can be done.
If the self-cleaning mechanism is a mechanical mechanism, the clogging of the coating material can be reliably prevented with a simple mechanism.

[0030]

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

Example 1 A concrete drainage pit (5 m × 5 m × 2 m) having poor flowability of air with water accumulated at the bottom was subjected to pretreatment for coating the concrete surface. As a pretreatment, the surface was thoroughly washed with water and left for 24 hours. Two-component curing type water-based epoxy resin-based undercoat for the concrete surface to be coated (Tough Guard EW
A primer (manufactured by Nippon Paint Co., Ltd.) was roller-applied at a rate of about 150 g / m ² and then left for 24 hours.
At this time, the solvent had almost no effect on the worker during the undercoating. Separately, 57 parts by weight of crude MDI (Millionate MTL, manufactured by Nippon Polyurethane Industry Co., Ltd.), polypropylene oxide (Newpol PP-3000, Sanyo Chemical Industries) as an isocyanate component (hereinafter referred to as "A component") for forming a polyurea anticorrosive film. (Manufactured by K.K.) 55 parts by weight were mixed and reacted to prepare an isocyanate prepolymer. As the polyamine component (hereinafter referred to as "B component"), 50 parts by weight of polyethertriamine (Jeffermin T-5000, manufactured by Heightsman Specialty Chemicals), polyetherdiamine (Jeffermin D-2000, Heightsman.
A mixture obtained by mixing 25 parts by weight of Specialty Chemicals) and 25 parts by weight of an aromatic diamine (Etacure 100, manufactured by Albemarle Corporation) was prepared. A two-liquid collision mixing type spray device (manufactured by Gasmer) was used as the spraying device. In this case, the collision mixing ratio of the A component and the B component is about 1/1 by volume, and the NCO index, which is the ratio of the amino group in the B component to the isocyanate group in the A component, is about 1.05. Met. A GX-7 gun manufactured by Gasmer was used as a spray gun.
The raw material temperature was 55 ± 5 ° C. for both the A component and the B component, and the raw material supply pressure was 7 to 12 MPa, and the primer-coated concrete surface was coated. Five seconds after applying the polyurea agent, the coated surface was touched with a finger, but it was already dry to the touch.

The environmental humidity during the anticorrosion coating was 80% RH or more. The film thickness of the polyurea material was 1-2 mm. Despite the high humidity environment, the coated concrete surface was a normal surface without wrinkles, unevenness, peeling and cracking. In order to confirm the quality of the obtained coating system, a cement mortar board (70 mm x 70 mm x 20 mm) according to JIS K 5410, which was sufficiently polished on the surface with No. 150 polishing paper and then washed with water, was separately provided. It was prepared, and undercoating and polyurea anticorrosion film formation were performed under the same conditions as above. The coated mortar material thus obtained was allowed to stand for 7 days and then a performance test was conducted. The test conditions and results are shown below.

Performance Test (1) Appearance of Anticorrosion Coating The appearance was visually observed. There were no wrinkles, spots, peelings, and were. (2) Adhesive force It was measured using a Kenken-type adhesive force tester. 20 kg / cm
^It showed an adhesive force of ² or more. (3) Acid resistance After dipping in a 10% sulfuric acid aqueous solution for 60 days, the appearance was visually observed. There were no abnormalities such as swelling, swelling, softening and elution in the anticorrosive film. In addition, for the test piece after the test, (2)
Adhesion test was carried out in the same manner as above, but 20 kg / cm ²
The above adhesive strength was exhibited. (4) Alkali resistance It was immersed in a saturated aqueous solution of calcium hydroxide for 60 days. There were no abnormalities such as swelling, swelling, softening and elution in the anticorrosive film. Further, the test piece after the test was subjected to the adhesive force test in the same manner as in (2), and showed an adhesive force of 20 kg / cm ² or more.

From the above results, this coating system is suitable for anticorrosive use of concrete exposed to severe conditions such as sewage treatment facilities, despite the shortened construction process of two steps of undercoating and topcoating. However, it was confirmed that it can be applied sufficiently.

Comparative Example 1 Two-component curing type water-based epoxy resin undercoat (Tough Guard EW
Instead of the primer, made by Nippon Paint Co., Ltd., a solvent-type moisture-curable isocyanate-based undercoat (Nippeculin Color Primer, made by Nippon Paint Co., Ltd.) was used, and the anticorrosion construction was carried out in the same manner as in Example 1. However, the solvent volatilized from the undercoat paint at the time of undercoat coating deteriorates the work environment, which may adversely affect the human body and cause a risk of explosion, so the work had to be stopped midway.

Comparative Example 2 In applying a polyurea agent to a cement mortar material, A
The mixing ratio of the component and the B component is about 0.5: 1.0 by volume ratio.
The anticorrosion coating was performed in the same manner as in Example 1 except that the above was used. In this case, the NCO index was about 0.53. The resin applied to the article to be coated did not cure well, had tackiness, and was not practical.

Comparative Example 3 In applying a polyurea agent to a cement mortar material, A
The mixing ratio of the component and the B component is about 1.0: 2.0 by volume ratio.
The anticorrosion coating was performed in the same manner as in Example 1 except that the above was used. In this case, the NCO index was about 2.1. The resin applied to the article to be coated did not cure well, had tackiness, and was not practical.

Comparative Example 4 As component A, 122 parts by weight of crude MDI (Millionate MTL, manufactured by Nippon Polyurethane Industry Co., Ltd.) and 118 parts by weight of polypropylene oxide (Newpol PP-3000, manufactured by Sanyo Chemical Industry Co., Ltd.) were mixed and reacted. The isocyanate prepolymer thus obtained was prepared. Also, as the B component,
Polyether triamine (Jeffermin T-500
0, made by Heightsman Specialty Chemicals)
20 parts by weight, polyether diamine (Jeffamine D
-2000, 20 parts by weight of Heightsman Specialty Chemicals, aromatic diamine (Ethacure 1)
00, manufactured by Albemarle Corporation) 60 parts by weight were mixed to prepare a mixture. Except that the collision mixing ratio of the A component and the B component was about 2.2: 1.0 (NCO index became about 1.05) by volume ratio,
It was applied to a cement mortar board in the same manner as in Example 1.
The obtained coating resin was very hard and brittle, and easily cracked on impact.

Comparative Example 5 As the component A, 31 parts by weight of crude MDI (Millionate MTL, manufactured by Nippon Polyurethane Industry Co., Ltd.) and 29 parts by weight of polypropylene oxide (Newpol PP-3000, manufactured by Sanyo Chemical Industry Co., Ltd.) were mixed and reacted. The isocyanate prepolymer thus obtained was prepared. Further, as component B, 45 parts by weight of polyethertriamine (Jeffermin T-5000, manufactured by Heightsman Specialty Chemicals), polyetherdiamine (Jeffermin D-20)
00, 45 parts by weight of Heightsman Specialty Chemicals, aromatic diamine (Ethacure 10)
0, manufactured by Albemarle Corporation) was mixed to prepare a mixture. Except that the collision mixing ratio of the A component and the B component was about 0.53: 1.0 (NCO index became about 1.05) by volume ratio,
It was applied to a cement mortar board in the same manner as in Example 1.
The resulting coating resin is very soft and tacky,
It wasn't practical.

[0040]

As described above, according to the present invention, the discharge of the volatile solvent can be suppressed, and the concrete anticorrosion can be applied even in a closed place where the air flow is poor and the humidity is relatively high. Further, according to the present invention, it is possible to form an anticorrosion coating that can withstand high environmental load conditions in a short time.

[Brief description of drawings]

FIG. 1 is a structural diagram of a spray coating device.

FIG. 2 is a sectional view showing the structure of a mixed coating gun.

FIG. 3 is a process drawing showing an example of the present invention.

[Explanation of symbols]

 10 coated surface 24 masking material 26 masking material 30 spray nozzle 32 coating film X boundary line between masking area and coating area

Claims (6)

[Claims] 1. A concrete anticorrosion construction method for forming an anticorrosive film on a surface to be coated, wherein a cured coating film of a two-component curable water-based epoxy resin is previously formed as an undercoating film on the surface to be coated, Then, an organic polyisocyanate or a partial prepolymer obtained by reacting a part of the isocyanate groups in the organic polyisocyanate with a polyol having a molecular weight of 200 to 8000 or an isocyanate component (A) composed of a mixture thereof, and an average molecular weight of 100
0 to 10000, excluding 100 parts by weight of polyoxyalkylene polyamine (a) having two or more aliphatic amino groups per molecule, and toluene diamine,
A polyamine component (B) comprising 15 to 100 parts by weight of an active aromatic diamine (b) having no electron-withdrawing group in an aromatic nucleus and having an alkyl substituent having 5 or less carbon atoms at a position adjacent to an amino group. A high-pressure two-liquid collision mixing type in which the equivalent ratio of the amino groups in the polyamine component (B) to the isocyanate groups in the isocyanate component (A) is 1 / 0.7 to 1 / 1.5. A construction method for concrete anticorrosion, which comprises applying and curing by a spraying method using a spraying device. 2. A polyoxyalkylene polyamine (a) having an average molecular weight of 1,000 to 10,000 and containing two or more aliphatic amino groups per molecule, and an electron-withdrawing group in the aromatic nucleus excluding toluenediamine. Otherwise, at least one of the active aromatic diamines (b) having an alkyl substituent having 5 or less carbon atoms at a position adjacent to the amino group is at least partly or entirely a primary amino group and a general formula CH ₂ = C (R) -Y (wherein R represents hydrogen or a methyl group, Y represents an electron-withdrawing group), and a modified by a Michael addition reaction with an unsaturated hydrocarbon compound represented by The method for corrosion protection of concrete according to claim 1, which is a modified polyamine having a secondary polyamine. 3. The method for constructing concrete anticorrosion according to claim 2, wherein Y is an ester residue, a ketone residue, a cyano residue, a substituted or unsubstituted amide group, a sulfonic acid residue or a sulfonic acid ester residue. . 4. The thickness of the anticorrosion coating is 0.3 to 10 mm.
The construction method for concrete anticorrosion according to claim 1, 2 or 3. 5. A masking not adhering the coating agent adjacent to a coating area where the coating agent is adhered to form a coating film on a surface to be coated on which the coating agent is adhered to form a coating film. A masking method for providing a region is used, wherein the masking method is between a sticking surface part that can be stuck to and peeled from the surface to be coated, and the surface to be coated, and more than the thickness of the coating film. A step (I) of preparing a masking material having a large interval and having an eaves portion that projects outward from the edge of the sticking surface portion, wherein the sticking surface portion of the masking material is arranged in the masking region , The tip of the eaves part,
The concrete corrosion protection construction method according to claim 1, which comprises the steps (II) and (II) of the step (II) of applying the masking material to the surface to be coated so as to be arranged in the coating area. . 6. The concrete anticorrosion construction method according to claim 1, wherein the surface to be coated is a concrete surface of a concrete wastewater treatment facility.