JP3420100B2 - Coating method of waterproof coating on cast iron pipe joint end face - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fast-curing,
The present invention relates to a method for applying a water-stop coating , which has high strength and can provide a coating film having excellent adhesion to cast iron and mortar surfaces. [0002] Ductile cast iron pipes (hereinafter referred to as cast iron pipes) are mainly used for water supply, sewage, agricultural water, industrial water, and the like. Usually, a mortar lining is provided on the inner surface of the cast iron pipe for internal corrosion protection. In particular, in a large diameter cast iron pipe with a pipe diameter of 900φ or more,
At present, almost 100% has mortar lining on the inner surface. [0003] Of the cast iron pipes, straight pipes are manufactured as a fixed length and have a length of 4 m to 6 m depending on the diameter. These fixed length cast iron pipes are painted and lined in a predetermined manner. However, at the laying site, it is necessary to cut and connect the fixed length pipes as necessary. However, the cut cross section, of course, has fresh cast iron exposed and no paint adhered. Therefore, the end face of the incision tube is
Normally, anticorrosive coating is required before joining. [0004] At the laying site, when the joining of the pipeline is completed, a water pressure test is performed to test whether or not the joint is defective. Since this is performed in one-day work units, if the part to be replaced is a cut cast iron pipe, the anticorrosion coating film may come into contact with water in a short time. The anticorrosive paint applied to the end face of the cut pipe at the joint between the cast iron pipes in the cast iron pipe line (hereinafter, simply referred to as “joint”) must be applied to the joint of the cast iron pipe within a short time after the coating. Since it is necessary to conduct a hydraulic test, anticorrosive paints are required to be quick-drying. In addition, it is needless to say that quality conforming to the K-139 standard (paint standard for cast iron pipe) or K-135 (liquid epoxy resin paint for water service, coating method) specified by the Japan Water Works Association (JWWA) is required. . That is, in the case of a large-diameter pipe having a diameter of 900 mm or more, an end face treatment is important because a test method in which only a connection portion called a test band is performed independently. That is, in this test method, a rubber dam is attached near the connecting portion on the inner surface of the pipe to make the connecting portion independent.
In order to apply water pressure to this location, if water leaks from the boundary between the cast iron and the mortar lining at the pipe end, the water pressure will not increase, and the increased water pressure will decrease, and the inspection will fail. Become. [0007] Therefore, the coating material for treating the cut end face of the cast iron pipe must be capable of preventing water leakage from the joint between the cast iron and the mortar lining at the pipe end by coating the cut end face of the cast iron pipe. is there. [0008] The end face treatment coating is a painting at a laying site, and the painting is performed by a person engaged in plumbing work. Therefore, it is common to end with a coloring painting far from the original purpose. For the purpose of coloring, the strength of the coating film is necessary, but in order to secure the strength, the required film thickness must be applied. Of course, instructions are given to give the film thickness in the construction manual, etc., but the coloring painting is the substance as described above. Therefore, the performance required for the paint on the cut end surface of the cast iron pipe is as follows: (1) JWWA K-139 or K-135 must be suitable for the water quality test. (2) It is fast-curing and has a fast rise in strength. (3) The coating film strength is high. (4) Good adhesion to cast iron pipe and mortar lining. (5) The wet / dry relationship should be as close to 1 as possible (that is, the property that the painted portion becomes dry as it is). Such properties are required. In addition, even in the uncut standard length tube, especially at the insertion port and the receiving port of the standard length tube, since the boundary between the cast iron portion and the mortar lining is usually exposed, a paint having the above-described properties is used. It is preferable to paint the exposed portions before the hydraulic test of the pipeline. Means for Solving the Problems The present inventors have conducted intensive studies on a method of applying a paint to be applied to an end face of a joint portion of a cast iron pipe satisfying the above requirements, and as a result, have used the method. (1) An average of 1.5 or more epoxy groups per molecule is used as a paint.
Having an epoxy equivalent in the range of 170 to 250.
Liquid epoxy resin without solvent at high temperature. (2) Active hydrogen equivalent is 9
0-100 amine-based curing agent, (3) diluent, and (4) constitution
Thick film can be painted by using paint made of pigment ,
It has been found that the present invention has been found to be fast-curing, has high coating film strength, and to prevent water from leaking from the boundary between the cast iron and the mortar lining at the pipe end. That is, the present invention provides a mortar lining.
Is to apply a waterproof coating to the end face of the cut pipe of the cast iron pipe.
(1) An average of 1.5 or more water-blocking paints per molecule.
Having an epoxy group having an epoxy equivalent of 170 to 250
A solvent-free liquid epoxy resin at room temperature in the range of (2)
Amine-based curing agent having an active hydrogen equivalent of 90 to 100;
Paint characterized by comprising an excipient and (4) extender pigment
It is about the method . DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail. The epoxy resin used in the present invention has an average of 1.5 or more epoxy groups per molecule,
A liquid epoxy resin having an epoxy equivalent of ℃ 250 at room temperature (25 ° C.), for example, bisphenol compounds such as bisphenol A and bisphenol F, polyphenol compounds such as resorcinol and hydroquinone, and polyphenol compounds such as phenol novolak and cresol novolak And epichlorohydrin: derived from polyhydric alcohols such as butanediol, hexanediol, neopentyl glycol, trimethylolpropane, glycerin, pentaerythritol, diethylene glycol, polyethylene glycol, dipropylene glycol, and polypropylene glycol, and epichlorohydrin. What is: 3,4-epoxycyclohexylmethyl (3,4-epoxycyclohexane) carboxylate, 3,4-epoxy 6-methyl-cyclohexylmethyl (3,4-epoxy-6-methylcyclohexane) carboxylate alicyclic epoxy compound: phthalic acid,
Those derived from polycarboxylic acids such as terephthalic acid, tetrahydrophthalic acid, hexahydrophthalic acid, trimellitic acid and hydroxycarboxylic acids such as oxybenzoic acid and oxynaphthoic acid and epichlorohydrin: aniline, phenylenediamine, diamino It is derived from a polyvalent amino compound such as diphenylmethane, a hydroxyamino compound such as aminophenol or aminocresol, and epichlorohydrin. The epoxy resin has a polyurethane skeleton and a polybutadiene skeleton,
It may be a compound in which a plurality of epoxy groups are bonded to a part of a molecule, or an epoxy compound having a hydantoin ring. These epoxy resins may be used alone or in combination of two or more. The epoxy resin used in the present invention has an epoxy equivalent of 170 to 250, preferably 18
It is in the range of 0 to 210, and it is an essential condition that it is a solvent-free liquid at normal temperature. If the epoxy equivalent is less than 170, it is not preferable in terms of maintaining the film strength and long-term performance of the obtained coating film. Conversely, if it exceeds 250, the coating material tends to have high viscosity and the amount of solvent used becomes large. However, it is not preferable in terms of securing the film thickness. The curing agent used in the present invention is an amine curing agent, and any known curing agent for a compound containing an epoxy group can be used without any particular limitation. Examples of such amine-based curing agents include, for example, aromatic polyamines such as phenylenediamine, tolylenediamine, diaminodiphenylmethane, and diaminodiphenylsulfone: diaminocyclohexylmethane, 3,9-bis (3-aminopropyl) 2, Aliphatic polyamines such as 4,8,10-tetraoxaspiro (5,5) undecane:
Addition products of these polyamines with the epoxy resin and / or monoepoxy compound: diamines such as ethylenediamine and xylylenediamine and adipic acid;
Polyamidoamines condensed with dicarboxylic acids such as dimer acid: 2-methylimidazole, 1-benzyl-2
Imidazole compounds such as -methylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-methylimidazole trimellitate: addition reaction product of the imidazole compound and the epoxy resin: 2-methylimidazoline Compounds such as imidazoline: guanidine compounds such as dicyandiamide: 1,4-
Tertiary amine compounds such as diazabicyclo [2,2,2] octane: compounds such as novolak salts of 1,8-diazabicyclo [5,4,0] undecene-7. The active hydrogen equivalent of the amine-based curing agent depends on the water quality , surface properties (wrinkles,
Considering factors such as cloudiness and handling (pot life, amount added to epoxy resin, etc.), the active hydrogen equivalent is 90%.
Is 100. The amine curing agents may be used alone or as a mixture of two or more. The amount of the amine-based curing agent used is the same as in the case where the curing agent is usually used, and the amount used may be adjusted as needed. The diluents used in the present invention include reactive diluents (monofunctional and bifunctional or higher polyfunctional) and non-reactive diluents (benzyl alcohol, xylene resin) which are usually used in solvent-free epoxy paints. , Toluene resin, etc.). From the viewpoint of quick curing, the sum of the two is preferably 40% or less based on the total amount of the epoxy resin and the curing agent.
For further lowering the viscosity, a normal organic solvent (other than an aliphatic hydrocarbon such as a mineral terpene) may be added within 5% for the purpose of adjusting the coating workability. For further dilutions,
It is not preferable because it adversely affects the securing of the coating film thickness and the rise of curing. As the extender used in the present invention, a known inorganic filler used in a usual epoxy resin composition is appropriately used. Specific examples include the following. Calcium carbonate, barium sulfate, crystalline silica, fused silica, amorphous silica, alumina, hydrated alumina, magnesia, talc, mica, clay, ceramic powder, glass fiber powder and the like. The extender pigment alone,
Alternatively, they may be used as a mixture of two or more of these. Considering that the extender pigment used in the present invention can be handled without a solvent, the amount of the extender pigment is 30 to 12 with respect to the total amount of the epoxy resin and the amine-based curing agent.
0% by weight, preferably 40 to 100% by weight. The paint of the present invention may optionally contain
You may mix | blend a coloring pigment. Examples of the coloring pigment include carbon black, titanium oxide, and red iron oxide. The coloring pigment is, for example, 0.1% of the total amount of the pigment.
-50% by weight, preferably 1.0-35% by weight. If necessary, the paint of the present invention may contain an organic filler such as a cured thermosetting resin powder or a thermoplastic resin powder, or a reinforcing material such as natural and / or synthetic fiber powder. In addition to the epoxy resin, amine-based curing agent, diluent, and extender pigment described above, the coating composition of the present invention may further comprise, if necessary, a surface conditioner used in ordinary epoxy resin paints, Foaming agents, dispersants (wetting improving materials), coupling agents, plasticizers, solvents, curing catalysts, dyes, wetting agents, leveling agents, thixotropic agents, and the like can be used. However, those containing heavy metals cannot be used. The paint of the present invention can be produced by the same general stirring and mixing equipment and processing conditions as in the ordinary method for producing an epoxy resin paint. The equipment used includes a mixing roll, a dissolver, a planetary mixer, a kneader, an extruder, and the like. As processing conditions, heating may be performed to dissolve and / or lower the viscosity of the epoxy resin or the like and to improve the stirring and mixing efficiency. Further, cooling may be performed to remove frictional heat, reaction heat and the like. The time for stirring and mixing may be determined as necessary, and is not particularly limited. The present invention will be described in more detail with reference to the following examples. In the examples, "parts" and "%" are shown on a weight basis. <Examples 1 to 3 and Comparative Example 1> Pigment dispersion of a base compound having the composition shown in Table 1 with a dissolver (the degree of dispersion was JI
SK-5400 4.7.2 10-20μ of the linear method
m) and mixed with a curing agent immediately before use to conduct various tests. Table 2 shows the results. (Viscosity of paint) The main component and the curing agent component are stored in advance in a thermostat at 20 ° C., and the viscosity immediately after mixing is measured with a Brookfield viscometer, and the viscosity is expressed in poise. (Sagging property of paint) JIS-
K-5400 6.4 Based on the test procedure for sagging,
It is applied to a 150 × 150 × 2 mm glass plate using a sag tester. After measuring the coating film thickness of each gap of the sag tester with a wet gauge, the wet film thickness that does not cause dripping while holding the glass plate vertically is defined as the dripping limit film thickness. (Curability of paint) Using a paint whose viscosity was measured, 70 ×
It is applied to a 150 × 2 mm glass plate with a 10 mil applicator, and the curability at 20 ° C. is determined according to JIS-K-5400.
6.5. (5) Measure based on (C). At the same time, observe the surface condition. (Pot life of paint) 100m of paint whose viscosity was measured
80 ml is placed in a polycup and left at 20 ° C., and the viscosity at regular intervals is measured with a Brookfield viscometer, and the time to reach twice the initial viscosity is defined as the pot life. (Adhesion with mortar) The surface of a commercially available concrete block for paving is sanded using a disk sander to remove latencies, and then coated with a coating amount of 150 g / m ² . Immediately after painting, a steel specimen (40 × 40 × 5) for a small adhesion tester manufactured by Sakuma Koki Co., Ltd.
mm) on the coating film and left indoors. After leaving for one week, the periphery of the specimen is cut off using a cutter, connected to a small adhesive tester main body to measure the adhesive force, and at the same time, observe the state of breakage. [Table 1] * 1: manufactured by Yuka Shell Epoxy Co., Ltd. Epoxy equivalent: 188, resin content: 100%, number of epoxy groups per molecule contained on average 1.8 or more. * 2: Yuka Shell Epoxy Co., Ltd., epoxy equivalent 25
0, the resin content is 100%, and the number of epoxy groups per molecule is 1.7 or more on average. * 3: Sakamoto Yakuhin Kogyo Co., Ltd. epoxy equivalent 160, resin content 100%, bifunctional reactive diluent * 4: Air Products Co., Ltd. toluene resin, resin content 100%, non-reactive diluent resin * 5: Takara Maika NO.
35 * 6: Sedimentable barium sulfate L100 manufactured by Sakai Chemical Co., Ltd. * 7: Carbon black MA manufactured by Mitsubishi Chemical Corporation * 8: Aerosil 380 manufactured by Nippon Aerosil Co., Ltd. * 9: Active hydrogen equivalent manufactured by Daito Sangyo Co., Ltd. 92.5, modified meta-xylene diamine type curing agent, resin content 100% <Example 4 and Comparative Example 2> Using a 1000φT type ductile cast iron pipe, the paint shown in the example was brush-coated on the joint receiving port and the end face of the insertion port so that the film thickness at the time of wet was 100 μm. After drying and curing for hours, the following tests were performed. The coating materials used in the test and the results of the test are shown in Table 3. (1) Test water pressure: 0.49 MPa (5 kgf / cm ² ) (2) Loading time: 5 minutes (3) Judgment: 80% (0.392 MPa) after 5 minutes
(4Kgf / cm ² )) If passed, pass. (Based on the test band water pressure test based on the 1990 water plate design guideline and commentary published by the Japan Water Works Association) [Table 3] Table 3 According to the method of the present invention, the paint applied to the joint end face of the cast iron pipe with the mortar lining is quick-curing, has high strength, and can be applied to the joint end face. Thus, it is possible to provide a coating film having excellent water stopping properties of a cast iron tube.

Continued on the front page (51) Int.Cl. ⁷ Identification code FI F16L 58/06 F16L 58/06 58/10 58/10 (72) Inventor Yoshisada Michiura 33 Minaminakaokamoto, Izumisano-shi, Osaka (72) Inventor Shinichiro Ime 1-3-33-1002 Midori, Tsurumi-ku, Osaka-shi, Osaka (72) Inventor Norio Yamada 1-1-3, Aobadai, Izumi-shi, Osaka (56) References JP-A-55-125168 (JP, A) JP-A-59-78267 (JP, A) JP-A-58-222810 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B05D 7/14 B05D 7/24 302 C09D 5 / 08 C09D 163/00-163/10 C09J 163/00-163/10 B28B 21/94 F16L 58/00-58/18 F16L 58/10

Claims (1)

(57) [Claim 1] A method of applying a water-stop coating to an end face of a cut pipe of a mortar-lined cast iron pipe, wherein the water-stop coating comprises (1) an average per molecule. Having 1.5 or more epoxy groups and an epoxy equivalent in the range of 170 to 250;
A coating method comprising: a liquid epoxy resin which is solvent-free at room temperature; (2) an amine curing agent having an active hydrogen equivalent of 90 to 100; (3) a diluent; and (4) an extender pigment.