JPS5956583A - Method for preventing corrosion by covering of structure to be prevented from corrosion - Google Patents

Abstract

PURPOSE:To prevent the corrosion of a structure to be prevented from corrosion by covering, by coating the surface of the structure with an undercoating material contg. isocyanate and by covering the undercoating material with a covering material impregnated with a wax-base anticorrosive mixture contg. a compound contg. active hydrogen. CONSTITUTION:The surface of a structure to be prevented from corrosion is coated with a liq. undercoating material contg. isocyanate. An anticorrosive mixture contg. a compound contg. active hydrogen which causes an addition reaction with isocyanate in the undercoating material is prepared. The base of the mixture is vegetable, animal or mineral wax and/or tar. A nonwoven fabric, cloth, a plastic film or a thin rubber sheet is impregnated or coated with the anticorrosive mixture to form a tapelike or sheetlike covering material, and said under coating material is covered with the covering material.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides the following features:
The present invention relates to a method for preventing corrosion of a skin by applying a tape-like or sheet-like coating phase impregnated or coated with a corrosion-preventing mixture.

Traditionally, for pipes such as water pipes, gas pipes, and oil pipes, as well as steel structures such as bridges, towers, and tanks, coating methods such as tape wrapping or sheet covering have been used as one of the corrosion prevention methods. is being carried out.

The following methods are mainly used to prevent blisters: (a) applying a adhesive material such as butyl rubber to a base material such as a plastic sheet or a rubber sheet; There is a method of impregnating a non-woven fabric or cloth with a rust-preventing mixture as the main component and coating the material in the form of a tape or sheet.

However, in the case of the former precautionary tape or sheet coated with a rubber-based adhesive, it is difficult to remove the protruding fixed parts such as bolts and nuts from the construction, or uneven parts such as welded parts, as well as complex protruding shapes such as 7-lunges and valves. Due to the somewhat hard characteristics (rigidity) of this type of tape or sheet itself,
There were problems in that it had poor conformability, making it difficult to coat smoothly, and that gaps were likely to be formed in the overlapped portions, making corrosion likely to occur due to water infiltration.

On the other hand, in the case of the latter type impregnated with an anti-fft mixture, since the base material is nonwoven fabric or cloth, it easily overlaps uneven parts or special protruding parts of steel structures, and also creates voids in overlapped parts. It has advantages such as separation, but on the other hand, the coating material is adhered only by the viscosity of waxes such as petrolatum, so
Adhesive strength is low, and especially in the case of anti-corrosion coatings, adhesives have the disadvantage of being easy to peel off from the surface of the structure.

With this in mind, as a method to supplement the adhesive strength with the surface of steel structures, hardening reactants, such as epoxy and amines, are added to the rust-preventing mixture containing waxes as the main components to improve adhesion and R concentration. Although it is considered that the coating material has a short pot life after the addition of reactants, mixing, impregnating, and coating must be carried out at the construction site, making the process extremely complicated. , it was not practical.

The present invention has been made in view of the above circumstances, and its purpose is to make it easy to coat with a coating material even if the 4N structure to be protected against corrosion has uneven parts or parts with special protruding shapes.
Moreover, at that time, no voids are created in the overlapped part,
Furthermore, it is an object of the present invention to provide a coating corrosion prevention method that significantly improves the adhesive strength of coating materials.

Such a feature of the present invention is that after applying a liquid undercoat containing incyanate to the surface of the structure to be protected against corrosion, active hydrogen (for example -〇H1 -NH2, etc.) and whose main ingredient is at least one selected from vegetable, animal, or mineral waxes and tar'fJi. The basis of this method is that it is coated with a glass film, a thin rubber sheet, etc. in the drawing room or with a tape-shaped or sheet-shaped covering material applied.

From this K, in the present invention, the isocyanate of the undercoating material and the compound containing active hydrogen in the rust preventive 7it 2n material on the side of the substrate undergo a polyaddition reaction, for example, in the case of a hydroxyl group,
Urethane bonding force (generated). This reaction occurs smoothly at room temperature, and curing is completed in about 10 hours. Therefore, the coating material is bonded integrally with the undercoat layer, and eventually the corrosion-protected structure of the coating material is bonded. The strength of stone adhesion to objects has been greatly improved,
Easy to use if PJP. That is, a stable anticorrosive effect can be maintained. Also, at this time,
At the same time, since the aggregation power of the rust-preventing additive to be treated is increased, the adhesive strength of the coating material is also improved from this point of view. In this case, the coating phase consists of a non-woven fabric, cloth, Pujisnak film, thin rubber sheet, etc. impregnated with the above-mentioned anti-rust mixture. Since it is coated on the undercoat material, it has good compatibility with the coated structure, and in particular, it prevents the formation of voids in the overlapping parts, even in structures to be protected that have uneven parts or special protruding shapes. , can be coated smoothly. Furthermore, during work, in the case of urethane reaction, the pot life in the curing station is relatively long, about 10 hours, and the coating work can be carried out smoothly and workability is good.

In the present invention, examples of compounds containing isocyanates contained in the undercoat include tolylene diisocyanate, polyphenylene polymethylene polyisocyanate, and incyanate prepolymers obtained by adding isocyanate monomers to polyester, castor oil, polyether, etc. It is desirable that all of them have good coating properties and low toxicity. Of course, these undercoating materials themselves should have good adhesion (adhesiveness) to the surface of the structure to be protected from corrosion, for example, the surface of a steel structure.

On the other hand, as a compound to be added to a rust preventive mixture containing waxes and tars, a compound that undergoes a polyaddition reaction with teriyaki isocyanate is selected, for example, 'H%-NI(2,-NH
Examples include those having COR. Specific examples of compounds containing hydroxyl groups include polyester polyol, polyoxyalkylene boriol,
Examples include polybutadiene polyol and polycarbonate polyol. In addition, examples of the compound containing an amide group include polyamide (resin, aniline formaldehyde resin, etc.).

4. The vegetable, animal, or mineral waxes and tars that are the main components of the anticorrosive mixture are those that have been conventionally used in anticorrosive coating compositions, including vinegar. Examples include waxes such as cotton wax, wool wax, petrolatum, and paraffin, and tars such as petroleum tar and coal tar. Considering the manufacturing of the covering material and the ease of handling during the 11-hour process, it is desirable that the melting point of the helmet and ξ is about 0 to 100°C. Also,
In addition, in the anti-fl mixture, inorganic fillers such as talc, clay, fine silica powder, calcium carbonate, anti-rust pigments such as zinc powder and red lead, or oil-soluble anti-flour agents may be added as appropriate. You may add it, or you may also add the curing accelerator you received.

Examples of the present invention will be described below along with comparative examples.

<Example> First, as an undercoat, a polyether-based isocyanate adduct (Viprene P-760, trade name) all-iron plate (7C
mX 100m) (approx. 100g/cr
n 2) Do.

Next, a non-woven fabric trap was impregnated with a rust-preventing mixture having the following composition and heat-mixed at about 80°C to produce a tape-shaped covering metal plate having a thickness of 1.2 m.

Coating material formulation: 100 parts petrolatum/polybutadiene polyol 40 N (PO1yb
OIR45TTT, product name)・talc
50 I-dibutyltin laure-h 0
．． 1# After that, one coated phase (
5cm x 25c1n) was attached to the above iron plate.

Then, the adhesive force between the coating material and the iron plate (180° beering method) was measured using a tensile tester and left for 24 hours.

In addition, the other one was a coating material (
(5c]n) was wrapped around the iron plate. And 2
After standing for 4 hours, salt spray test (J Engineering 5Z0236)'e
A wet box test (50'O, 95 cm or more of wet eaves, J Engineering 5z0236) was carried out for 1,000 hours, and then the covering and alternating materials were removed to investigate the occurrence of rust on the surface of the iron plate.

<Comparative Example ■> As a coating material, a nonwoven fabric was impregnated with a rust-preventing mixture made by heating and mixing at approximately 80°C, consisting of the following formulation, and a 1 m thick
After making a tape-like product of 100 m and pasting or wrapping it on an iron plate in the same manner as in the example of the present invention, the same test was conducted.
50 〃・Petroleum sulfonate Ba
Comparative Example ■ A butyl rubber adhesive was applied to a vinyl chloride film to produce a vinyl chloride anticorrosion tape with a thickness of Q and 4m+n, and this was applied to an iron plate in the same manner as in the example of the present invention. After pasting or wrapping, similar tests were conducted.

Next, the test results are shown in Table 1.

Table 1: Table of Test Results According to Table 1 above, in the case of the examples of the present invention, the adhesive strength was considerably greater than that of Comparative Examples I and II, indicating that the adhesive strength was greatly improved. Moreover, no rust occurred. On the other hand, in the case of Comparative Example I, although the anticorrosive performance was good, the adhesive strength was poor. In the case of Comparative Example (3), although the adhesive strength was relatively high, it was found that rust occurred on the edge portion of the tape and some of the edge portions of the iron plate.

Of course, the present invention can be applied not only to corrosion-protected steel structures but also to other metal structures that have the same corrosion problems as iron.

As is clear from the above description, according to the present invention, even if the structure to be protected against corrosion has uneven parts or parts with a special protruding shape, it is easy to coat with the coating material, and at the same time, voids occur in the overlapping parts. It is possible to provide an excellent corrosion protection method for coating a structure to be protected, which significantly improves the adhesive strength of the material to be shrunk.

Patent applicant: Hatakura Kusen Co., Ltd. Agent: Shigenori Ishidoya, patent attorney

Claims (1)

[Claims] After applying an undercoat material containing incyanate to the surface of the structure to be protected against corrosion, a compound having active hydrogen that reacts with the isocyanate of the undercoat material is added thereto, and a compound of vegetable, animal or A rust-preventing mixture containing at least one selected from mineral waxes and tars as a main component can be applied to non-woven fabrics or cloth, as well as plastics,
Impregnation into rubber films, sheets, etc.'=! 1. A corrosion protection method for coating a relic to be protected, characterized by coating it with a coated coating material.