JPH05220451A - Lining method of metal pipe or metal valve with urethane elastomer - Google Patents

Abstract

PURPOSE:To provide a lining method of a metal pipe or a metal valve with urethane elastomer wherein the metal pipe and the metal valve have high wear resistance, corrosion resistance, water proofness, and excellent initial adhesion property. CONSTITUTION:At first, as a primary primer, a primer containing polyvinyl butyral as a main component is applied to the inner face of a metal pipe or a metal valve and dried. Further as a secondary primer, a polyurethane based primer containing isocyanate group is applied and dried. Then, two liquid hardening-type polyurethane elastomer raw liquid is applied thereon by a pouring method or a spraying method and cured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lining method for lining a urethane pipe having excellent wear resistance, corrosion resistance, and water resistance on the inner surface of a metal pipe or a metal valve.
Specifically, a primer containing polyvinyl butyral as a main component as a primary primer is applied and dried on the inner surface of a metal tube or a metal valve, and then a polyurethane-based primer containing an isocyanate group is applied and dried as a secondary primer. When the two-component curing type polyurethane elastomer stock solution is applied and lined by pouring or spraying, it improves the initial adhesion of the urethane elastomer to the metal tube or metal valve. The present invention relates to a method of lining a urethane elastomer to a metal tube or a metal valve, which is free from peeling of the urethane elastomer from the tube or the metal valve, and swelling.

[0002]

2. Description of the Related Art Conventionally, it has been widely carried out to use metal pipes such as iron pipes to transport particles and fluids, and recently, iron and steel pipes have also been used to transport earth and sand, ores and other powders and grains. Metal tubes have come into use. However, even if these metal pipes are used as they are, the pipe walls are worn by the earth and sand or the like passing therethrough, so that a pipe lined with a polyurethane elastomer having excellent wear resistance is generally being used.

As a method for lining a polyurethane elastomer, generally, a surface of a metal tube is treated with a primer, and then a two-component curing type urethane elastomer composition is applied by rotating the tube by pouring, spraying, brushing or centrifugal projection. Although a method has been adopted, the urethane elastomer may peel off from the metal tube due to curing shrinkage when the urethane elastomer composition cures. Further, in this case, even if there is no peeling at the initial stage, if it is immersed in water for a long period of time, the adhesive strength is greatly reduced and satisfactory water resistance cannot be obtained.

[0004]

Therefore, as a countermeasure against this problem, a method of applying a primer twice has been proposed (JP-A-57-184475 and JP-A-58-20).
1638, JP-A-64-2477). In this method, an epoxy-based primer is applied to a metal surface, a urethane-based primer is then applied, and a polyurethane elastomer is lined thereon. However, in all of these methods, the initial adhesive force was slow to develop, and the peeling phenomenon during lining could not be completely eliminated. Furthermore, in order to prevent water from penetrating into the polyurethane resin, a method of using a resin in which glass flakes or the like is mixed as a penetration resistance material in the polyurethane resin is also disclosed, but this method is generally the original characteristic of the polyurethane resin. It is not preferable because it reduces wear resistance. As a measure against this, a method of applying a predetermined centrifugal force to accumulate the resistance material on the metal surface side is also disclosed (Japanese Patent Publication No. 2-3827).
No. 2). However, in this method, in order to sufficiently integrate the resistance material, it is necessary to slow the curing speed of the resin,
Remarkably low productivity and impractical. Further, these methods have no effect of improving the initial adhesiveness.

[0005]

Means for Solving the Problems When the urethane elastomer is lined with a metal pipe or a metal valve, the present inventors obtain a lining material having excellent initial adhesion, strong adhesion, and excellent water-resistant adhesion. As a result of earnest research on the method, a primer containing polyvinyl butyral as a main component as a primary primer was applied and dried on the inner surface of a metal tube or a metal valve, and then a polyurethane-based primer containing an isocyanate group was applied and dried as a secondary primer. After that, by applying a two-component curing type polyurethane elastomer stock solution thereon and curing it, the initial adhesiveness was significantly improved, and it was found that the water-resistant adhesiveness was also excellent, and the present invention was completed.

The present invention will be described in detail below. The polyvinyl butyral used as the primary primer in the present invention is obtained by reacting polyvinyl alcohol obtained by saponifying polyvinyl acetate with butyraldehyde under an acid catalyst. If necessary, basic zinc chromate, phosphoric acid, alcohols, etc. are added to form a primer. For this, a commercially available product generally defined as JIS-K-5633 and generally called an etching primer or a wash primer can also be used.

As the polyurethane primer used as the secondary primer, organic polyisocyanates can be used alone or in combination of two or more kinds. It is also possible to use a urethane prepolymer having a terminal isocyanate group obtained by reacting this organic polyisocyanate with a polyol (note that this urethane prepolymer generally contains unreacted organic polyisocyanate). ).

Examples of the organic polyisocyanate include hexamethylene diisocyanate, lysine diisocyanate, isophorone diisocyanate, xylene diisocyanate, cyclohexane diisocyanate, toluidine diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4'- Diphenylmethane diisocyanate, p-phenylene diisocyanate, m-phenylene diisocyanate, 1,
Examples include 5-naphthylene diisocyanate, triphenylmethane triisocyanate, and mixtures and modified products thereof.

The above-mentioned polyols have a linear terminal hydroxyl group, and preferably have a molecular weight of 500 to 6,0.
The diols of 00 may be used alone or in combination of two or more. Moreover, you may use together polyhydric alcohol.

Molecular weight having linear terminal hydroxyl group 500-
Examples of 6,000 diols include polyester polyols and polyether polyols. Examples of the polyester polyol include a polyester polyol obtained by polycondensing a polyhydric alcohol and a polybasic carboxylic acid or a hydroxycarboxylic acid,
Furthermore, polycaprolactone diols obtained by ring-opening addition polymerization of a lactone such as ε-caprolactone in the presence of glycol and the like can be mentioned.

Examples of the polyhydric alcohol mentioned here include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 2,3-butylene glycol, 1,4-butylene glycol and 2,2 '. −
Dimethyl 1,3-propanediol, diethylene glycol, 1,5-pentamethylene glycol, 1,6-hexamethylene glycol, cyclohexane 1,4-diol, cyclohexane 1,4-dimethanol, etc., alone or in combination of two or more. Can be used.

Examples of polybasic carboxylic acids include succinic acid, maleic acid, adibic acid, glutaric acid, pimelic acid, speric acid, azelaic acid, sebacic acid, phthalic acid, isophthalic acid, terephthalic acid, hexadroterephthalic acid, Hexahydrophthalic acid and the like can be used alone or in combination of two or more kinds. Also useful are castor oil, which is a condensate of polyhydric alcohol and hydroxycarboxylic acid, or a reaction product of castor oil and ethylene glycol, propylene glycol, or the like.

As the polyether polyol, for example, a product obtained by addition-polymerizing one or more alkylene oxides such as ethylene oxide, propylene oxide and butylene oxide to a compound having two or more active hydrogens, or tetrahydrofuran. Examples thereof include polytetramethylene glycol obtained by ring-opening polymerization. In this case, examples of the compound having two or more active hydrogens include amines such as ethylenediamine, hexamethylenediamine, diethyltoluenediamine, ethanolamine and propanolamine, in addition to the polyhydric alcohols and polybasic carboxylic acids described above. Alkanolamines, resorcin, polyphenols such as bisphenol, castor oil and the like.

Like the primary primer, such a secondary primer is generally used with a solvent. As the solvent for the secondary primer, a solvent inert to the isocyanate group is used. Examples thereof include toluene, xylene, methyl ethyl ketone, methylene chloride, cellosolve acetate, methyl isobutyl ketone, ethyl acetate and butyl acetate.

As the polyurethane-based primer serving as the secondary primer, one containing an isocyanate group-containing silane compound can be used. This isocyanate group-containing silane compound is the above-mentioned organic polyisocyanate and aminosilane compound and / or mercaptosilane compound in an equivalent ratio of isocyanate groups to amino groups and / or mecapto groups of 1 / 0.20 to 1 /
It is obtained by reacting at 0.95. The isocyanate group-containing silane compound is preferably 1 to 50% by weight based on the total amount of the polyurethane-based primer (excluding the solvent content).

The two-component curing type polyurethane elastomer used in the present invention is typically a two-component curing type polyurethane elastomer composed of a urethane prepolymer having a terminal isocyanate group and a polyol compound.

As is well known, the urethane prepolymer is obtained by reacting the above-mentioned polyols with the above-mentioned organic polyisocyanate. The polyol compound is a mixed solution containing a polyol, a chain extender such as a polyhydric alcohol, a urethanization catalyst and the like. A two-component curing type polyurethane elastomer is obtained by heating these at room temperature or about 50 to 80 ° C. and mixing and curing at a predetermined ratio. Examples of the metal pipe for lining the two-component curing type urethane elastomer include a cast pipe and a steel pipe. Further, examples of the metal valve include a casting valve.

The method of lining the two-component curing type urethane elastomer on the metal pipe or the metal valve is as follows. After treating the inner surface of the metal tube or the metal valve with a grinder or a wire brusher, a primary primer containing polyvinyl butyral as a main component is applied to the surface and dried to form a primary primer layer. At this time, the thickness of the primary primer after drying is 5 to 300 μ, preferably 20 to
Apply so as to have a thickness of 200μ. Then, a polyurethane primer is applied to the primary primer layer and dried to form a secondary primer layer. Also in this case, the thickness of the secondary primer after drying is 5 to 300 μ, preferably 20 to 200.
Apply so that it becomes μ. Then, a polyurethane primer is applied to the primary primer layer and dried to form a secondary primer layer. Also in this case, the secondary primer is applied so that the thickness after drying is 5 to 300 μ, and preferably 20 to 200 μ. Here, the primary primer layer and the secondary primer layer are formed by applying the respective primers by brush coating, flow coating, spraying or the like.
These are usually left for 2 to 3 hours at room temperature until the solvent is scattered, but it is preferable to heat the underlying metal tube or metal valve to about 40 to 80 ° C. in order to sufficiently remove the solvent. . Then, a two-component curable polyurethane elastomer stock solution is applied to the surface of the secondary primer layer by a pouring method, a spray method or the like and cured. In this case, the temperature difference between the temperature of the underlying metal tube or metal valve and the temperature of the stock solution of the two-component curing type polyurethane elastomer is 0 to +10.
Set in the range of 0 ℃ and lining. More specifically, 40 parts of the two-part curable polyurethane elastomer stock solution is used.
Heat to 80 ° C and set metal tube or valve to 80-16
Heat to about 0 ° C. If the temperature of the two-part curable polyurethane elastomer stock solution is lower than 40 ° C, the viscosity of the stock solution becomes high and it is difficult to lining. On the contrary, if the temperature is higher than 80 ° C, the stability of the stock solution will be deteriorated. If the temperature of the metal pipe or the metal valve is lower than the temperature of the undiluted solution of the two-component curing type polyurethane elastomer, sufficient adhesiveness cannot be obtained due to shrinkage of the two-component curing type polyurethane elastomer during curing. If the temperature difference between the underlying metal tube or metal valve and the two-component curable polyurethane elastomer stock solution is set to 100 ° C. or higher, urethane is likely to foam during lining. Further, depending on the shape of the metal tube or the metal valve, the two-part curable polyurethane elastomer stock solution may be applied by dipping, brushing or the like.

[0019]

EXAMPLES The present invention will be specifically described below with reference to examples, but this is only one mode and the present invention is not limited to these examples. In addition, all "parts" and "%" in the text of the examples indicate weight basis.

[Synthesis Example of Polyurethane-Based Primer] [Synthesis of UT-M1] 1000 g of polytetramethylene glycol having a molecular weight of 1000, 180 g of 1,4-butanediol, and 270 g of trimethylolpropane were dissolved in 4000 g of toluene, and nitrogen was added. 1650 g of an 80/20 mixture of 2,4-tolylene diisocyanate and 2,6-tolylene diisocyanate was added under a stream of air and reacted at 80 ° C. for 5 hours to obtain a polyurethane-based primer containing an isocyanate group. Next, 750 g of 4,4′-diphenylmethane diisocyanate and 600 g of γ-mercaptopropyltrimethoxysilane were mixed with toluene 1 under a nitrogen stream.
The reaction was carried out in 000 g at 80 ° C. for 5 hours to obtain an isocyanate group-containing silane compound, and the entire amount was added to the above-mentioned polyurethane primer to obtain UT-M1.

[Synthesis of UM-A1] 1000 g of polytetramethylene glycol having a molecular weight of 1000, 180 g of 1,3-butanediol, and trimethylolpropane 40
0 g of toluene 4000 g and methyl ethyl ketone 10
It was dissolved in 00 g of a mixed solvent, and it was 4.4'-under a nitrogen stream.
Add 3000 g of diphenylmethane diisocyanate,
Reaction was carried out at 80 ° C. for 3 hours to obtain a polyurethane-based primer containing an isocyanate group. Next, 1000 g of 4,4′-diphenylmethane diisocyanate and 1200 g of γ-aminopropyltrimethoxysilane were reacted in 2000 g of toluene under a nitrogen stream at 80 ° C. for 5 hours to obtain an isocyanate group-containing silane compound.
UM-A1 was used in addition to the polyurethane-based primer described above.

[Synthesis of Epoxy Primer (Comparative Example)] Epicoat 1001 (manufactured by Yuka Shell Co., bisphenol A type epoxy resin, epoxy equivalent 450 to 50)
0) 300 g and Epicoat 152 (produced by Yuka Shell Co.,
Phenol novolac type epoxy resin, epoxy equivalent 1
72 to 179) 140 g and 150 g of toluene as a solvent were used as the main agent of the epoxy primer. 270 g of metaxylylenediamine (manufactured by Mitsubishi Gas Chemical Co., Inc.) and 60 g of Epicoat 828 (manufactured by Yuka Shell Co., bisphenol A type epoxy resin, epoxy equivalent 184 to 194) were reacted at 90 ° C. for 5 hours under a nitrogen stream, and then released. After cooling, 290 g of toluene, 90 g of ethyl cellosolve, and 170 g of methyl ethyl ketone were added thereto to form a uniform solution, which was used as a curing agent for the epoxy primer. The main agent and the curing agent were mixed at a ratio of 3/1 (weight ratio) and used as a primer.

[Synthesis Example of Two-Component Curing Polyurethane Elastomer Stock Solution] [Synthesis of PR-1] 1000 g of polytetramethylene glycol having a molecular weight of 2000 and 750 g of 4,4′-diphenylmethane diisocyanate were mixed at 80 ° C. under a nitrogen stream for 3 days.
The reaction was carried out for a time to obtain a urethane prepolymer PR-1 having a terminal isocyanate group content. [Synthesis of GR-1] 1000 g of polytetramethylene glycol having a molecular weight of 1000 and 1,4-butanediol 4
GR-1 was prepared by uniformly mixing 00 g of the urethanization catalyst and 0.14 g of dibutyltin dilaurate.

[Examples 1 to 4 and Comparative Examples 1 to 4] To a 70 × 150 × 3.2 mm steel plate degreased with toluene, the primer synthesized in the above synthesis example or an existing primer was prepared.
The coating was applied so that the film thickness after drying was about 30 μm, and dried in an oven at 60 ° C. for 30 minutes. When the secondary primer synthesized in the above Synthesis Example is further applied onto this primer layer, the dry film thickness is about 30 as in the case of the primary case.
After being coated so as to have a thickness of μ, it was dried at 60 ° C. for 30 minutes.

Then, 200 g of PR-1 and 70 g of GR-1 each prepared by the above synthesis example were defoamed at 80 ° C. under a reduced pressure of 20 mmHg for about 20 minutes, and then stirred. Stir and mix for about 30 seconds so as not to entrain air, and pour the resulting mixture onto a primer-coated steel plate to a thickness of about 2 mm and cure to prepare test pieces for measuring various adhesive properties. The characteristics were evaluated. The results are shown in Table 1 below. The injection of the two-component curing type polyurethane elastomer was performed on the same day as the application of the primer.

[0026]

[Table 1]

In Table 1, as the ready-made primers, polyvinyl butyral type primers such as vinylex (produced by Shinto Paint Co., Ltd.) and Shinto Wash (produced by Shinto Co., Ltd.) are used.
Made), Phenolic resin primer Chemlock 218
(Made by LORD FAR EAST INC.) Was used. The evaluation criteria of the actual pipe confirmation test in Table 1 are as follows. ×: Peeling occurred during lining. △: Peeling occurred after water resistance test. ○: No abnormality after water resistance test.

The evaluation method is as follows. [Measurement method for normal adhesive strength] Test piece as it is at 23 ° C., 6
It was left in 0% RH (relative humidity) for 5 minutes, 15 minutes, 60 minutes, 1 day, and 7 days. Then, a notch having a width of 1 inch was made in parallel in the longitudinal center of the test piece until it reached the surface of the steel plate, one end was peeled off, a grip portion was formed, and the peel strength was measured at an angle of 90 degrees at a speed of 50 mm / min.

[Measurement Method of Water-Resistant Adhesive Strength] In the same manner as the above-mentioned measurement method of normal adhesive strength, after making a notch in a test piece, the test piece was immersed in warm water at 70 ° C. and left standing for a predetermined number of days at a uniform temperature, The 90-degree peel strength was measured in the same manner as the method for measuring the normal adhesive strength.

[Confirmation test using actual pipe] Length 1 m, diameter 35
After applying each predetermined primer to a 0 mm cast iron pipe, while rotating the pipe, the two-component curing type polyurethane elastomer stock solution, PR-1 / GR-1 is poured so that the thickness after lining is 2 mm and cured. Let After complete curing, the appearance of the lining product was inspected to confirm whether there was any abnormality such as peeling. In the case of no abnormality, after making a notch of 30 cm in length in the center of the pipe to reach the underlying metal pipe, the pipe was immersed in room temperature water for 1 month and tested to see if peeling occurred by immersion. .

As is clear from the test results shown in Table 1, all of the methods of the present invention show high initial adhesive strength and excellent final normal adhesive strength. In addition, almost no decrease in adhesive strength was observed even after immersion in hot water at 70 ° C for 7 days.
Furthermore, in the actual pipe test, no abnormality was found by the method of the present invention.

[0032]

According to the method for lining a urethane pipe of a metal pipe or a metal valve of the present invention, a primer having polyvinyl butyral as a main component is applied as a primary primer to the inner surface of the metal pipe or the metal valve, and dried. As a polyurethane primer containing an isocyanate group as the next primer is applied and dried, a two-component curing type polyurethane urethane elastomer stock solution is applied and cured, so that the initial adhesion of the urethane elastomer to the metal pipe or metal valve is greatly improved. It has the advantages of improved water resistance and excellent water resistance.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location B05D 7/24 Y 8720-4D T 8720-4D F16L 57/00 A 7403-3J 58/10 7403- 3J (72) Inventor Masayoshi Kitagawa 1-12-19 Kitahorie, Nishi-ku, Osaka City, Osaka Prefecture Kurimoto Iron Works Co., Ltd. (72) Inventor Junji Matsunaga 1-12-19 Kitahorie, Nishi-ku, Osaka City, Osaka Kurimoto Iron Works (72) Inventor Nobuo Aoki 1-12-19 Kitahori, Nishi-ku, Osaka City, Osaka Prefecture Kurimoto Iron Works Co., Ltd. (72) Nobuhide Takada 1-12-19 Kitahori, Nishi-ku, Osaka City, Osaka Prefecture Kurimoto Iron Works Co., Ltd.

Claims (2)

[Claims] 1. A primer mainly comprising poly (vinyl butyral) as a primary primer is applied and dried on the inner surface of a metal pipe or a metal valve, and a polyurethane-based primer containing an isocyanate group is applied and dried as a secondary primer on the primer. A method for lining a urethane pipe to a metal pipe or a metal valve, which comprises applying a two-component curing type polyurethane elastomer stock solution on the resulting solution and curing it. 2. The method according to claim 1, wherein when the two-component curing type polyurethane elastomer stock solution is applied and lined, the temperature difference between the metal pipe or the metal valve and the two-component curing type polyurethane elastomer stock solution is set to 0 to + 100 ° C. Lining method for metal pipes or valves of urethane elastomer.