JPH078975B2 - Anticorrosion paint and method for producing anticorrosion treated steel pipe columns - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an anticorrosion paint and a method for producing a steel pipe column anticorrosion-treated by using the anticorrosion paint.

(Prior art) Conventionally, when using a steel pipe pillar with zinc plating for a communication utility pole, the ground portion is usually 0.1 mm with a tar epoxy paint.
It is painted to the thickness of. This existing steel pipe column is frequently removed temporarily due to route changes, customer requests, and aesthetic demands in tourist areas.

The wall thickness of the steel of the steel tube column is 3 mm, and the standard value of its bending strength is
1.961 × 10 ^-3 Pa (200kgf / cm ² ) but safety factor is 2
Since it is designed as 3.923 × 10 ^-3 Pa (400kgf /
It has a strength of cm ² ). However, these steel pipe columns are not coated with anticorrosion coating in the underground buried parts other than the ground, so the zinc plating wears out in 5 to 6 years, the base of the steel pipe columns corrodes and shows red rust, and the thickness reduction Wake up. If the wall loss due to corrosion of the steel tube column is uniform, a wall loss up to 1.5 mm is acceptable, but the once removed steel tube column tends to further increase red rust due to oxidation. 1.5m reduction in thickness of removed steel pipe columns
Even if it is less than m, if it is reused in a state where the buried part corrodes and red rust is generated, the corrosion progresses rapidly and the long-term guarantee for the strength of the steel pipe column cannot be made. In many cases, they are discarded as sorted items, which is economically disadvantageous because new steel pipe columns are used. As a method of remedying this drawback, the purpose is to repair the corrosion points in the underground buried parts of steel pipe columns that have been removed for one day, and it has sufficient anticorrosion performance even with simple rust prevention work that can be performed at construction sites, and It is desired to develop an anticorrosion paint having excellent economical efficiency.

Various urethane compositions have been proposed for the purpose of waterproofing buildings and preventing corrosion of metals. A typical example is a composition comprising urethane prepolymer, petroleum resin, petroleum heavy cracked oil, water or polyol. Applicability of these various existing materials to the above-mentioned steel pipe columns was examined, but favorable results were not obtained, and there were problems in terms of adjustment of the coating film thickness and weather resistance of the cured coating film.

(Problems to be Solved by the Invention) An object of the present invention is to solve the above-mentioned problems of the prior art, improve adhesion to a steel pipe column and corrosion resistance of an embedded part of the steel pipe column, and improve weather resistance. By improving the reliability in terms of both anticorrosion properties, it is possible to prolong the service life of steel pipe columns, or to reuse steel pipe columns after removing the rust in the corroded parts of the steel pipe columns. The present invention provides a novel anticorrosion paint and a method for producing a steel pipe column which is anticorrosion-treated with the same.

(Means for Solving the Problems) As a result of intensive studies to solve the above problems, the inventors of the present invention set a special polyurethane composition as shown below to achieve the intended purpose. We have found that we can achieve it.

INDUSTRIAL APPLICABILITY The present invention uses a urethane prepolymer having an isocyanate group at the end as a main agent, a hydroxyl group-containing compound, an aliphatic or alicyclic petroleum resin, and a hardener containing a metal oxide, and an anticorrosive paint using the same. It relates to a method of manufacturing a steel pipe column.

The anticorrosion paint of the present invention comprises a main agent and a curing agent, and both are mixed immediately before use to form a paint.

A compound obtained by reacting a polyol with a diisocyanate is used as the urethane prepolymer having an isocyanate group at the terminal in the present invention. Polyester polyol, polyether polyol, etc. are used as the polyol, but polyether polyol is preferable from the viewpoint of flexibility, water resistance and weather resistance, and polypropylene glycol-based polyol, polyethylene glycol-based polyol, polytetramethylene glycol-based polyol. , Polyoxypropylene glycol-based polyol, etc. are used. As the diisocyanate,
Diphenylmethane diisocyanate, tolylene diisocyanate, hexamethylene diisocyanate, etc. are used. A urethane prepolymer having an isocyanate group at the terminal is synthesized from these polyols and diisocyanate. The mixing ratio of the polyol and the diisocyanate is set to a ratio in which the diisocyanate group becomes excessive. Considering the viscosity of the paint, the weight average molecular weight of the polyol is 50
A range of 0 to 3000 is preferred. Examples of the polyether polyol include PPG-1000, PPG-2000, PP manufactured by Osaka Soda.
There are G-3000, TG-4000, etc., and as the polyester polyol, for example, Nitporan 1004, Nitsuporan 2006, Desmophen800, Desmophen800 manufactured by Nippon Polyurethane Industry Co., Ltd.
There are 1100 and so on.

As the hydroxyl group-containing compound, water, lower alcohols, polyhydroxy compounds and the like are used, but it is preferable to use water from the viewpoint of reactivity. Petroleum resin is residual oil obtained by extracting benzene, toluene, and xylene from naphtha cracked oil 150 to 2
It is obtained by polymerizing a fraction at 50 ° C. In the prior art, it was said that this can be applied as it is as a component of a urethane composition to the use of an anticorrosion paint as it is, but it is a field requiring weather resistance and high anticorrosion performance as the object of the present invention. Is not suitable for. That is, as will be described later, when the aromatic unsaturated bond remains in the petroleum resin, the weather resistance is significantly deteriorated. Therefore, the present invention requires the use of aromatic or cycloaliphatic petroleum resins that do not contain aromatic unsaturated bonds. Examples of petroleum resins include aliphatic petroleum resins, aromatic petroleum resins, aliphatic / aromatic copolymer petroleum resins and aliphatic / alicyclic copolymer petroleum resins. Aliphatic or alicyclic compounds containing no bond can be directly applied to the present invention. However, aromatic compounds such as dicyclopentadiene and C ₉ alkylbenzene cannot be used as they are, but they can be used by converting them to aromatic unsaturated bonds by means such as hydrogenation.

Examples of the aliphatic or alicyclic petroleum resin that can be used in the present invention include, for example, Maruzen Petrochemical's trade names Marcaclear and Marcarets, Tonetsku's trade name Escoretz, Mitsui Sekiyu's trade name FTR, and Arakawa Chemical. The product name is Alcon.

As the metal oxide, oxides of alkaline earth metals such as calcium, magnesium and barium are used.

In addition, as inorganic compounds imparting anticorrosion properties, polyphosphates such as aluminum tripolyphosphate, aluminum phosphomolybdate, zinc calcium phosphate, chromates such as zinc chromate, chelate compounds such as ethylenediaminetetraacetic acid and diethylenetriaminepentaacetic acid, and tannic acid. Rust stabilizers such as dibutyltin laurylate, cobalt naphthenate,
It is also effective to use a metal salt such as zinc naphthenate, a curing accelerator such as amines such as triethyleneamine and tetramethylpolymethylenediamine, a pigment such as carbon, and a filler such as talc. The total amount of these additives is preferably 0.5 to 3.0 parts by weight with respect to 100 parts by weight of the coating material.

The ratio of the main agent to the curing agent and the ratio of the three components of the curing agent are not particularly limited, but the preferable ratio from the viewpoint of the viscosity of the fuel, the curing speed, and the physical properties of the coating film is the hydroxyl group-containing compound of the curing agent to the aliphatic or alicyclic group. Group petroleum resin vs metal oxide 10-20 parts by weight
The range is 40 to 70 parts by weight to 20 to 50 parts by weight, and the main agent to the curing agent is 40 to 50 parts by weight to 50 to 60 parts by weight.

The materials for the steel pipe columns are SS-41 steel plate and zinc plated SS-41.
There are steel plates, class 3 keren steel plates, etc.

The anticorrosive steel pipe column is manufactured by placing the anticorrosion paint of the present invention on the steel pipe column by a spatula or the like at room temperature while setting it on a coating device that horizontally supports and rotates the steel pipe column.

Hereinafter, the present invention will be described in more detail with reference to examples.

(Example) Example 1 As a polyether polyol, 48 parts by weight of PPG-1000 manufactured by Osaka Soda Co., Ltd., 24 parts by weight of PPG-3000 manufactured by Osaka Soda Co., Ltd., and 19.8 parts by weight of tolylene diisocyanate were used. While charging the flask and blowing nitrogen
The reaction was terminated at 130 ° C. for 8 hours at a viscosity of 100 poise (25 ° C.) and an unreacted isocyanate content of 4.0% by weight as the end point of the reaction. Next, charge about 2 parts by weight of toluene, stir, remove from the flask, put in a container,
Immediately, nitrogen substitution was performed to obtain the main agent.

Hydrogenated petroleum resin Marukalets 4006 (Maruzen Petrochemical Co., Ltd.)
44 parts by weight, magnesium oxide 27 parts by weight, magnesium carbonate 9 parts by weight, carbon 3 parts by weight, aluminum tripolyphosphate 10 parts by weight, tannic acid 0.3 parts by weight, zinc naphthenate 1.0 parts by weight, methanol 7 3 parts by weight of pure water
It was kneaded with a part by weight roll to obtain a curing agent. These main agents 45
Mix well at a ratio of 55 parts by weight with 55 parts by weight of curing agent, and immediately place it on a coating device that horizontally supports and rotates the steel pipe column.
A spatula coating was applied while rotating at rpm, and the coating was cured at room temperature to obtain a steel tube column with a coating thickness of 1.20 mm.

Example 2 As a polyether polyol, 36 parts by weight of PPG-4000 manufactured by Osaka Soda Co., Ltd., 36 parts by weight of PPG-1000 manufactured by Osaka Soda Co., Ltd., and 21.5 parts by weight of tolylene diisocyanate were charged into a flask. The reaction was terminated at a temperature of 100 ° C. for 6 hours while blowing nitrogen, and the viscosity reached 80 poise (25 ° C.) and the unreacted isocyanate content reached 5 weight percent. Next, add about 2 parts by weight of toluene, stir, remove from the flask, put in a container,
Immediately, nitrogen substitution was performed to obtain the main agent.

30 parts by weight of Maruzen Petrochemical's brand name Marca Clear 4003 as hydrogenated petroleum resin, 18 parts by weight of Maruzen Petrochemical's brand name Marukalets 100B as aliphatic petroleum resin, 23 parts by weight of calcium oxide and 13 parts of talc Parts by weight, 3.5 parts by weight of carbon, 5 parts by weight of aluminum phosphomolybdate PM300C under the trade name of Kikuchi Dye Industry Co., Ltd., and 10 parts by weight of pure water were kneaded with a roll to prepare a curing agent.

Sufficiently mix 48 parts by weight of main agent and 52 parts by weight of curing agent,
Immediately, the steel tube column was supported horizontally, and it was placed on a rotating coating device while applying a spatula while rotating at 15 rpm to cure at room temperature, and a steel tube column with a coating film thickness of 1.00 mm was obtained.

COMPARATIVE EXAMPLE 1 Popia # 30, a tar epoxy resin manufactured by Shinto Paint Co., Ltd.
00H was mixed in a proportion of 80 parts by weight to 20 parts by weight of the main agent to the curing agent to prepare a paint.
A spatula coating was applied while rotating at rpm, and the coating was cured at room temperature to obtain a steel tube column with a coating thickness of 0.10 mm.

Comparative Example 2 Marukalets 4006, which is the hydrogenated petroleum resin used in Example 1
Instead of, as an aromatic petroleum resin, Mitsui Petrochemical's trade name Petrosin PTR-80 was used to prepare a paint,
In the same manner as in the example, the steel tube column was rotated at 15 rpm and applied with a spatula to cure at room temperature to obtain a steel tube column having a coating film thickness of 1.0 mm.

The results of measuring the adhesive force between the coating film and the steel pipe columns for the steel pipe columns obtained in Examples 1 and 2 and Comparative Examples 1 and 2, and the paints used in this were applied to SS-41 steel plates (50 mm x 150 mm x 3.2 mm). The results of measuring the weather resistance and salt spray resistance of the test piece coated on
It was shown to.

(1) Adhesion was measured using an adhesion tester manufactured by Elcometer.

(2) The weather resistance test was performed using the Sunshine Weatherometer of the Suga Tester WEL-SH-2C. 10 appearance of coating
Observed with a double magnifying glass, those with no cracks and those without bleaching were marked with ○, those with cracks and those without some bleaching were marked with △. Those with a large crack or whitening were marked with x.

(3) The salt water spray test was conducted in accordance with JIS K 5400. After washing the coating film with water, the state of cracks and blisters was observed with the naked eye, and those without cracks and blisters were marked with ○, slightly cracked and blisters. Those with ∆, cracks and large blisters were marked with X.

(Effects of the Invention) The anticorrosion paint of the present invention is excellent in adhesion to a steel pipe column, weather resistance of a coating film applied to a steel plate, and anticorrosion property, and can be thickened by one coating. With the coating material of the present invention, it is possible to obtain a steel pipe column having excellent corrosion resistance and the like.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical display location C09D 175/04 PHW (72) Inventor Toshinobu Ueda 1-6 Uchisaiwaicho, Chiyoda-ku, Tokyo Nihonhon Telegraph and Telephone Corp. (72) Inventor Shigeru Hosono 1-1-6 Uchisaiwaicho, Chiyoda-ku, Tokyo Nihon Telegraph and Telephone Corp. (56) Reference JP-A-2-272013 (JP, A) JP-A-51 -146531 (JP, A)

Claims (2)

[Claims] 1. An anticorrosion paint comprising a urethane prepolymer having an isocyanate group at the terminal as a main agent, and a curing agent containing a hydroxyl group-containing compound, an aliphatic or alicyclic petroleum resin, and a metal oxide. 2. A method for producing an anticorrosion-treated steel pipe column, which comprises coating the anticorrosion paint according to claim 1 on a steel pipe column while rotating the steel pipe column and curing the coating.