JPS58199875A - Method for repairing part affected by pitting corrosion - Google Patents

Abstract

PURPOSE:To prevent the propagation of pitting corrosion of the steel of a structure and to allow a long-term anticorrosive effect to be shown, by filling a composition prepared by adding a curing agent to a base consisting of epoxy resin and glass flakes into the part of the structure affected by the pitting corrosion. CONSTITUTION:An anticorrosive composition is prepared by adding a suitable curing agent to a base consisting of 100pts.wt. epoxy resin or epoxy resin contg. about 33-80% bituminous substance and 13-200pts.wt. glass flakes. The composition is filled into the part of a steel structure affected by pitting corrosion, and it is dried. Thus, the propagation of the pitting corrosion is thoroughly prevented, and the structure can be used over a long term without exchanging the steel material.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pitting corrosion repair method for L1 steel. More specifically, by filling the site of pitting corrosion in the steel material with an anti-corrosion filler material that has excellent adhesion and anti-corrosion properties, the service life of the steel material can be significantly extended. How to do it.

In iron structures such as ships' tanks and holds, onshore storage tanks, bridges, and plants, which are subject to extremely severe corrosion, they come in contact with seawater, oils, animal and vegetable oils, ores, etc. In such cases, corrosion often occurs accompanied by pitting corrosion, and localized pitting corrosion may progress at a stress rate of 1 or more.In such cases, construction or During this period, penetration accidents due to corrosion will occur.

Conventionally, in order to prevent such corrosion, anti-corrosion measures such as anti-corrosion coating and cathodic protection have been applied at the time of construction or construction, and these measures have been effective to some extent. However, these anti-corrosion measures are not perfect;
It is inevitable that corrosion and pitting will occur and progress due to factors such as peeling and deterioration of the coating film and a decrease in the anti-corrosion current density. Especially when anti-corrosion measures such as those mentioned above are taken,
- When corrosion starts from a defective part, its progress is inhibited by healthy parts and does not spread to the surrounding area, but tends to progress as deep pitting corrosion, and corrosion accompanied by such pitting corrosion occurs. If this occurs, there is no appropriate way to maintain the structure other than completely renewing the steel in that area.

As a result of extensive research into solving this problem, the present inventors discovered the effect of a corrosion-resistant composition reinforced with glass flakes, and arrived at the present invention.

That is, the present invention provides: (1) jj-iX7 layer 13 to 20 to epoxy tree w11 or epoxy tree @1oo11 part containing bituminous material;
The anticorrosive composition obtained by adding 0 parts by weight to form a main ingredient and further adding a hardening agent is filled into the pitting corrosion occurring part of a steel structure to extend the service life of the steel structure. Anti-corrosion repair method.

(2) Ill! The method for repairing pitting corrosion according to claim 1, wherein the epoxy resin containing growth material contains 31- to 80-7 parts of bituminous material. :) It is.

The present invention will be explained in detail below.

The glass flator, which is an essential component used in the present invention, has a thickness of 0f-10 microns and a size of Mk dog length 1) was ~
A corrosion-preventing composition obtained by blending the scaly glass flakes of 3. with a polymeric film-forming material made of epoxy resin or bituminous epoxy resin is applied to the recesses and pitting corrosion areas of steel materials. When bitten, the glass flakes form a layered arrangement in the anticorrosion composition, absorbing the shrinkage stress generated by the over-hardened roots of the anticorrosion composition, and exhibiting strong adhesion to the substrate.
It significantly delays the speed at which permeable substances such as moisture, ions, and oxygen reach the base material, so it completely stops the progress of pitting corrosion, exerts a long-term corrosion effect, and can extend the service life of steel materials. .

Here, the content of glass flakes was set to 13 to 200 folds per part of the polymer film forming material 100]11 because the content of glass flakes was less than 13 parts by weight, and the above-mentioned shrinkage occurred. This is because the stress absorption effect and the effect of delaying the arrival speed of moisture, ions, oxygen, etc. cannot be expected, and 20
If it exceeds 0 parts by weight, the continuity of the polymeric film-forming material will be lost, making it impossible to obtain a uniform anticorrosion composition, and in any case, it cannot be used as an anticorrosion composition for filling pitting corrosion. be.

i9. The polymer film-forming material used in the present invention must be an epoxy resin or an epoxy resin containing bituminous material for the following reasons.

In other words, epoxy resin is a so-called two-component bonding material consisting of a main resin and a curing agent that is cured by a curing agent, and has a feature that it is extremely small compared to chemical resin-based bonding materials that have a main resin and a curing agent. This is because there are rumors ◆4 about whether it is possible to minimize the degree of shrinkage after pitting repair and thereby maximize the adhesion to the steel material.

Epoxy resins used in the present invention include bisphenol epoxy resins with epoxy equivalents in the range of 150-10 (10), bisphenol F-type epoxy 1M resins, and polyfunctional epoxy resins, among which epoxy Bisphenol A with an amount in the range of 150 to 3.0
1! Epoxy resins of Ii or bisphenol FIl are preferred.

The bituminous material used in combination with epoxy resin has a softening point of 10
Since it is possible to add asphalt below 0°C, water-based coal tar, and anti-corrosion properties, the service life of steel materials after pitting repair can be further extended.

Here, the bituminous quality in the epoxy resin is set in the range of 33- to 80-.If it is less than 33-, the water resistance improvement effect by bituminous does not appear, and if it exceeds 986%, the bituminous AlI
This is because the flexibility of the composition is lost due to No. 4, making it impossible to achieve the object of the present invention.

The curing agent used to cure epoxy resin is
Amine adducts, polyamide resins, polyamines, modified polyamines, etc., which are generally used for curing epoxy resins, are selected from these depending on the purpose, but aliphatic resins are especially used as solvent-free curing agents. Alternatively, aromatic polyamines are most suitable for achieving the objectives of the present invention.

In addition, the anticorrosion composition used in the present invention may further contain pigments such as extender pigments, coloring pigments, and rust-inhibiting pigments, as well as additives such as thickeners and silane coupling agents.

A method for repairing a site where pitting corrosion has occurred with the anticorrosive composition containing the glass flakes of the present invention is carried out as follows.

1. Prior to repair work, the construction area is sandblasted as in the case of general anti-corrosion coating.
Remove rust and dirt from IIIAT parts! l□ Remove. η1゜2 After sandblasting, pour the anti-corrosion composition into the pitting area and use a trowel to crack the light surface and spread it uniformly.

1 Bond on which the anticorrosive composition has dried, the entire part V (the same anticorrosion composition used for repair is applied with airless rivets to make the whole part smooth.

By the above construction, the pitting corrosion occurring site of the steel plate is completely filled and repaired, and the progress of pitting corrosion is completely stopped, so that the corrugated steel material can be used further without being replaced.

As explained above, the pitting corrosion repair method of the present invention
Apply an anti-corrosion composition containing Etkin resin or bituminous Etkin resin as a molecular film-forming agent, with gasis flakes as an essential ingredient, to areas where pitting corrosion occurred that required renewal work on steel materials. Therefore, this is a temporary method that provides a technology that allows steel materials to be reused without having to be replaced.

Hereinafter, the effects of the present invention will be explained in more detail with reference to Examples and Comparative Examples. In addition, parts and - in the examples are parts by weight, respectively.
Show the weight.

Examples 1 to 6 (1) Preparation of anticorrosive compositions Among the main ingredients of Examples 1 to 6 whose formulations are listed in Table 1, the components excluding gaff flakes and the silane coupling agent were mixed together [11, continued] After kneading and grinding using a roll mill, stir using a dipper type stirrer.
The flakes and a silane coupling agent were added to make the mixture uniform, and the main ingredients of Examples 1 to 6 were prepared.

Each curing agent was added to the obtained base agent and mixed to obtain anticorrosive compositions of Examples 1 to 6.

(2) Creation of a repair test plate, with accelerated test holes ★ Sandblasting using a shipbuilding steel plate to completely remove rust and deposits, covering the entire surface of the steel plate to a depth of 4 to 8 A pitting steel plate of 300 x 200 Use a spatula to create an even surface, 2
It was dried for 24 hours at 0° C. and 75 dFL.

Next, the same anti-corrosion composition used for pitting repair was applied to the upper plate by airless spraying so that the total dry film thickness was l■, and cured at 20°C and 75-1La for 7 days. After drying, the repair test plates of Examples 1 to 6 were prepared, and the following acceleration performance tests were conducted on these repair test plates.

(1) Salt water spray jI#c test 5 (5% Nact aqueous solution was continuously sprayed for one year under conditions of 1°C.

@) Humidity test: Continuously exposed to water vapor from tool LH for one year at 40°C.

(3) Salt water immersion test 4 @c,s % Naα aqueous solution was continuously immersed for one year.

←) Adhesion test The adhesion strength between the substrate and the coating film was measured using an adhesion tester for the test plate in item (3) after being immersed in salt water for one year.

The results obtained in the above tests are shown in Table 2.

In addition, as a comparative example, the results of an attempt to repair round pitting using a commercially available black agent type urethane paint are also shown on the wood surface in the same manner as in the examples.

As is clear from Table 2, the present invention shows that it can prevent pitting corrosion, and is extremely useful industrially.

, 11 Table 1 (Unit parts by weight) Note *l
Araldai) GY-260 (trade name, manufactured by Ciba Co., Ltd.) with a 9-bisphenol epoxy equivalent weight of 180 to 200.

Bottle 2 Epicron 830 (product name, Dainippon Ink Industries (
Epoquine equivalent of bisphenol F'Ii (manufactured by Co., Ltd.): 170
~190 things.

Hata 3 Takuron 15O (product name, manufactured by Yoshida Seiyuu) at
CCF-160 (product name, manufactured by Nippon Glass Fiber (FFI))
Jar 5 Benton 34 (4 product names, manufactured by National Red Co.)
a@KBM4G! (Product name, Shin-Etsu Chemical Co., Ltd. (Copper)) Australia 7HY-850 (Product name, Ciba Corporation) Schedule 2 Procedure Amendment (Voluntary) March 4, 1939 Showa S8 Mr. Kazuo Wakasugi, Commissioner of the Patent Office!, Indication of the case Showa S7 Patent Application No. 82722λ Name of the invention Pitting repair method 1 Relationship with the case of the person making the amendment Patent applicant 1-10-1 Yurakucho, Chiyoda-ku, Tokyo & Detailed description of the invention in the specification subject to amendment O Contents of the amendment As shown in the attached sheet, the detailed explanation of the invention in the specification is amended as follows.

(1) “It is...” on page 7, line 6 of the same book.

" is corrected to "...The amount of these curing agents used is determined by the company itself depending on the type of epoxy resin and curing agent used."

(2) "Tipper-type stirrer" in the fourth line of the first page of the same book is corrected to "disper-type stirrer."

-399-

Claims (2)

[Claims] (1) An anticorrosive composition obtained by adding 13 to 20 parts by weight of glass flakes to 100 parts by weight of epoxy resin or epoxy resin containing bituminous material, and further adding a hardening agent, is used to prepare steel structures. An anti-corrosion repair method characterized by filling the parts where pitting corrosion occurs and measuring the IJN of the service life of the steel structure. (2) The epoxy resin containing m growth quality is I! ! '# Claims containing from 33 to 80 Liao! !
The method for repairing pitting corrosion according to No. 1g4.