JP4179102B2 - Anti-corrosion method for concrete structures in sewerage facilities - Google Patents

Description

  The present invention relates to a method for preventing corrosion of a concrete structure in a sewer facility, and more particularly, to a method for preventing corrosion of a concrete structure in a sewer facility for preventing corrosion of the concrete structure due to sulfuric acid caused by hydrogen sulfide generated in the sewer facility. About.

Conventionally, anticorrosion coatings have been studied for the purpose of preventing corrosion of concrete structures in sewer facilities. In particular, as an anticorrosive coating for the purpose of preventing the occurrence of pinholes, a dry primer or wet method nonwoven fabric composed of synthetic resin fibers, natural fibers and inorganic fibers on the surface of a concrete structure, a liquid primer on a porous thin film sheet of woven fabric A film forming method is described in which a sheet layer impregnated with a resin is formed and then a film forming resin is spray-coated.
Japanese Patent Laid-Open No. 10-100300

  In the case of the coating formation method by spray coating as described above, the obtained anticorrosion coating cannot be found macroscopically, but microscopic pinholes are generated, which is sufficient as a countermeasure against pinholes. I can not say.

  The present invention has been made in view of the above circumstances, and the purpose thereof is not only a macroscopic pinhole that can be confirmed by visual observation, but also a corrosion prevention method for a concrete structure of a sewerage facility that does not have a microscopic pinhole. Is to provide.

  As a result of various studies on the cause of microscopic pinholes, the present inventor has obtained the following knowledge. That is, the viscosity of the film-forming resin used in the film-forming method by spray coating must be less than a viscosity that allows spray coating, for example, less than 1,000 mP · s. When such a low-viscosity resin is applied to the upper and side surfaces of a concrete structure, dripping of the resin occurs. As a result, coating unevenness occurs, and it is a pinhole when viewed microscopically. However, when a binder resin composition having a specific viscosity is applied to an inorganic paper having a specific basis weight with a trowel, a spatula, or a roller, surprisingly, dripping of the resin is prevented and a microscopic pin in the anticorrosion coating is provided. Generation of holes can be prevented.

The present invention has been completed based on the above findings, and the gist of the present invention is that a binder resin composition is formed after a step of forming a primer resin layer and a reinforcing material on the surface of a concrete structure of a sewerage facility. In a corrosion prevention method for a concrete structure including a coating step, the viscosity is 1,500 to 200,000 mP · s before or after applying an inorganic paper having a basis weight of 15 to 80 g / m ² as a reinforcing material. A sewerage facility characterized in that a binder resin composition is applied to inorganic paper, and the binder resin is infiltrated into the inorganic paper. It exists in the anticorrosion method of concrete structures.

  Hereinafter, the present invention will be described in detail. The anticorrosion method of the present invention is basically the same as a conventionally known method, and after a step of forming a primer resin layer and a reinforcing material on the surface of a concrete structure of a sewer facility, a binder resin composition The process of apply | coating. In addition, in this invention, before forming a primer resin layer, you may perform the base-material adjustment of the concrete structure surface by conventionally well-known film formation. In the present invention, an inorganic paper having a specific basis weight is used as the reinforcing material, and a binder resin composition having a specific viscosity is used as the binder resin composition. Adopt specific means.

  As the primer resin used in the present invention, resins exemplified in the binder resin described later can be used. And it is preferable that primer resin and binder resin are the same resin.

  The inorganic paper as the reinforcing material used in the present invention is obtained by uniformly dispersing inorganic powder or fine fiber thereof in water and making it paper by a wet or dry papermaking method. Specific examples include glass fiber paper, carbon fiber paper, rock wool fiber paper, mineral paper, and the like. By the way, mineral paper is a paper made from highly functional powder such as calcium carbonate, aluminum hydroxide, talc, activated carbon powder, calcium silicate, magnesium carbonate.

  In particular, short glass fibers having a diameter of 6 to 20 microns: glass fiber paper in which chopped strands are uniformly dispersed in water and made into paper by a wet papermaking method is preferable.

  The basis weight of the inorganic paper is 15 to 80 g / ·, preferably 26 to 75 g / ·. When the weight per unit area is less than 15 g / ·, the eyes are coarse, so that the occurrence of macroscopic pinholes cannot be prevented. On the other hand, when the basis weight exceeds 80 g / ·, impregnation with the binder resin becomes insufficient, and macroscopic pinholes cannot be prevented from being generated.

  The binder resin composition used in the present invention contains a binder resin, a curing agent, and a diluent. Furthermore, auxiliary agents such as conventionally used fillers, additives, sagging agents, colorants, extender pigments and the like can be included as necessary.

  As the binder resin, resins described in the corrosion control technology and anti-corrosion technology guideline for the sewerage facility concrete structure and the manual (Japan Sewerage Corporation) can be used. Examples include epoxy resins, vinyl ester resins, non-styrene type vinyl ester resins, solventless polyurethane elastomer resins, unsaturated polyester resins, modified silicone resins, polyurea resins, acryloyl modified acrylic resins, and the like.

  The curing agent is not particularly limited as long as it can cure the binder resin, and a known one is used. The diluent is not particularly limited as long as it dissolves the binder resin, and a known one is used.

  The viscosity of the binder resin composition is 1,500 to 200,000 mPa · s (25 ° C .: BH type rotational viscometer), preferably 3,000 to 50,000 mPa · s (25 ° C .: BH type rotational viscometer). is there. When the viscosity is less than 1,500 mPa · s, the binder resin composition tends to sag on the wall surface of the concrete structure, and uneven coating occurs, resulting in a microscopic pinhole. On the other hand, when the viscosity exceeds 200,000 mPa · s, the impregnation of the inorganic paper is insufficient and a macroscopic pinhole is easily formed.

  Among the above-described binder resins, an epoxy resin is preferable in consideration of adhesiveness, chemical resistance, shrinkage resistance, and handleability. Specific examples of the epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AD type epoxy resin, hydrogenated epoxy resin of the above resin, novolac type epoxy resin, glycidyl ester type epoxy resin, urethane modified epoxy resin , Nitrogen-containing epoxy resins, epoxy resins derived from alcohols, polybutadiene, natural rubber, rubber-modified epoxy resins derived from natural rubber having terminal carboxyl groups, flame retardant epoxy resins containing bromine, alicyclic epoxies Resin etc. are mentioned.

  Considering high curing reactivity or easy formation of a three-dimensional network structure in the cured product, an epoxy resin containing at least two epoxy groups in the molecule is preferable. Specifically, novolak type epoxy resins such as epichlorohydrin-bisphenol A type epoxy resin and epichlorohydrin-bisphenol F type epoxy resin are more preferable.

  The epoxy resins can be used alone or as a mixture. Moreover, it can be used as a mixture with the monoepoxy compound which reduces the viscosity of an epoxy resin.

  Examples of epoxy resin curing agents include triethylenetetramine, tetraethylenepentamine, diethylaminopropylamine, N-aminoethylpiperazine, m-xylylenediamine, m-phenylenediamine, diaminodiphenylmethane, diaminodiphenylsulfone, isophoronediamine, 2, Amines such as 4,6-tris (dimethylaminomethyl) phenol, tertiary amine salts, polyamide resins, imidazoles, dicyandiamides, ketimines, boron trifluoride complex compounds, phthalic anhydride, hexahydrophthalic anhydride , Tetrahydrophthalic anhydride, endomethylenetetrahydrophthalic anhydride, dodecinyl succinic anhydride, pyromellitic anhydride, chlorenic anhydride and other carboxylic anhydrides, alcohols, phenols, carboxylic acids, etc. And the like.

  Examples of the diluent for the epoxy resin include butyl glycidyl ether, phenyl glycidyl ether, alkyl glycidyl ether, 1,6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, and the like. Examples of the non-reactive diluent include phthalate plasticizers such as benzyl alcohol, dioctyl phthalate, and butyl benzyl phthalate.

  Furthermore, examples of the epoxy resin filler include heavy calcium carbonate, light calcium carbonate, kaolin, talc, silica, titanium oxide, aluminum silicate, magnesium oxide, zinc oxide, and carbon black. Examples of the additive include silane coupling agents such as aminosilane and epoxysilane.

  The anticorrosion coating is formed by any one of a trowel construction method, a spatula construction method, and a roller construction method. In consideration of workability, the roller construction method is preferable. The type of roller may be any of short hair rollers, medium hair rollers, and long hair rollers, but a non-foam roller is preferred.

  As the structure of the anticorrosive coating of the present invention, the design specification examples of the type C of the anticorrosion coating method described in the corrosion control technology of the concrete structure of the sewerage facility and the anticorrosion technology guideline / the manual (Japan Sewerage Corporation) and In the design specification example of Class D of the anticorrosion coating method, a structure using inorganic paper as a reinforcing material can be mentioned.

  According to the present invention, not only macroscopic pinholes that can be visually confirmed, but also anticorrosion coatings that do not have microscopic pinholes can be formed, and as a result, hydrogen sulfide generated in sewerage facilities The industrial value of the present invention is remarkable because the corrosion of the concrete structure by sulfuric acid is completely suppressed.

  EXAMPLES Hereinafter, although an Example demonstrates this invention still in detail, this invention is not limited to a following example, unless the summary is exceeded. The microscopic pinhole test uses a “TO-250C pinhole detector” (for concrete substrate) manufactured by Sanko Electronic Laboratory Co., Ltd. Inspected. The evaluation was performed with ◯: no pinhole, Δ: pinhole (5 or less / test plate), and x: multiple pinholes (6 or more / test plate).

  First, as substrate preparation, 100 parts by weight of a bisphenol A type epoxy resin (epoxy equivalent: 189 g / eq, manufactured by Japan Epoxy Resin Co., Ltd.), 46.1 parts by weight of talc, and a curing agent (manufactured by Dainippon Color Industry Co., Ltd .: trade name “ Epoxy-modified MXDA ”) 30.8 parts by weight of epoxy resin putty was applied to a concrete plate (JIS plate: 50 mm × 600 mm × 360 mm) with an adhesion amount of 1.0 kg / · and cured at 23 ° C. for 1 day. .

  Next, as Examples 1 to 5, bisphenol A type epoxy resin (epoxy equivalent: 189 g / eq, manufactured by Japan Epoxy Resin Co., Ltd.) 100 parts by weight, 1,6-hexanediol diglycidyl ether (produced by Sakamoto Pharmaceutical Co., Ltd.) 26. Undercoat epoxy resin composition containing 2 parts by weight, 23.1 parts by weight of talc and 34.5 parts by weight of a curing agent (manufactured by Dainippon Color Material Industries Co., Ltd .: trade name “epoxy modified MXDA”) (adhesion amount: 0.4 kg / (Epoxy resin equivalent)) was applied with a roller to form a primer resin layer, and then a glass paper having a basis weight shown in Table 1 was attached as a reinforcing material. And 100 parts by weight of bisphenol A type epoxy resin (epoxy equivalent: 189 g / eq, manufactured by Japan Epoxy Resin Co., Ltd.), 25 parts by weight of 1,6-hexanediol diglycidyl ether (manufactured by Sakamoto Yakuhin Kogyo Co., Ltd.), 11.1 weight by weight of talc Parts and a curing agent (Dainippon Color Material Co., Ltd .: trade name “epoxy-modified MXDA”) having 39 parts by weight and having the viscosity shown in Table 1 (adhesion amount: 0.3 kg / · (epoxy Resin conversion)) was applied with a roller and cured at 23 ° C. for 7 days to prepare an anticorrosion coating.

(Comparative Examples 1-6)
As Comparative Examples 1 to 6, as shown in Table 2, the anticorrosion coating was formed in the same manner as in Example 1 except that the composition of the reinforcing material, the amount of inorganic paper, and the viscosity of the epoxy resin composition were changed. Produced.

  In the table, as an epoxy resin composition having a viscosity of 200 mPa · s, 100 parts by weight of a bisphenol A type epoxy resin (epoxy equivalent: 189 g / eq, manufactured by Japan Epoxy Resin), 1,6-hexanediol diglycidyl ether (Sakamoto Yakuhin) Kogyo Co., Ltd.) 33.3 parts by weight and a curing agent (Dainippon Color Co., Ltd .: trade name “epoxy modified MXDA”) 40 parts by weight of epoxy resin composition, and viscosity: 250,000 mPa · s As an epoxy resin composition, bisphenol A type epoxy resin (epoxy equivalent: 189 g / eq, manufactured by Japan Epoxy Resin Co., Ltd.) 100 parts by weight, 1,6-hexanediol diglycidyl ether (produced by Sakamoto Pharmaceutical Co., Ltd.) 26.2 parts by weight , 16.9 parts by weight of talc and a curing agent (manufactured by Dainippon Color Material Industries Co., Ltd .: trade name “epoxy modified” XDA ") was used an epoxy resin composition comprising 30.8 parts by weight.

  As apparent from the above results, in the case of the example, no microscopic pinhole was confirmed as a result of the pinhole test. On the other hand, in the case of the comparative example 1 using a glass cloth as a reinforcing material and the comparative example 2 using a glass mat as a reinforcing material, microscopic pinholes were confirmed. Further, in both Comparative Example 3 when the basis weight of the glass paper was small and Comparative Example 4 when the basis weight of the glass paper was large, microscopic pinholes were confirmed. In Comparative Example 5 where the viscosity of the binder resin composition is low and in Comparative Example 6 where the viscosity of the binder resin composition is high, microscopic pinholes were confirmed.

Claims (2)

In a corrosion prevention method for a concrete structure including a step of forming a primer resin layer on the surface of a concrete structure of a sewerage facility and a step of applying a binder resin composition after applying a reinforcing material, Before or after applying the inorganic paper of 15 to 80 g / m ² , a binder resin composition having a viscosity of 1,500 to 200,000 mP · s is applied to the inorganic paper, and the binder resin is infiltrated into the inorganic paper. In addition, a corrosion prevention method for a concrete structure in a sewer facility, which employs iron, spatula, or roller application means for the application.   2. The anticorrosion method according to claim 1, wherein the inorganic paper is at least one selected from glass fiber paper, carbon fiber paper, and rock wool fiber paper.