JPH0848914A - Anticorrosive coating material - Google Patents

Abstract

PURPOSE:To obtain an anticorrosive coating material improved in anticorrosiveness by using an epoxy resin obtained from a dimer acid and a bisphenol epoxy resin and having a specified epoxy equivalent as the binder and specifying the pigment volume concentration. CONSTITUTION:A dimer acid in an amount of 20-60wt.% is esterified with 80-40wt.% bisphenol epoxy resin for about 3-4hr at about 130-150 deg.C to obtain an epoxy ester resin of an epoxy equivalent of 400-1000. This resin as a binder is mixed with a coloring pigment such as red iron oxide or carbon, an anticorrosive pigment based on a phosphate or a borate, a flaky pigment such as zinc or micaceous iron oxide and an extender pigment such as talc or clay in such amounts as to give a pigment volume concentration(PVC) in the range of 20-50% and a solvent such as xylenol to form a coating material. A specified amount of a curing agent such as a modified polyamideamine is added to the coating material to obtain an interval-free anticorrosive coating material for steel structures.

Description

Detailed Description of the Invention

[0001]

[Industrial field of application] Steel structures such as bridges, plants, and building steel frames are usually coated with an undercoat at the production plant, and are generally brought into the field, erected, then intermediate-coated and overcoated.
On the other hand, when the same kind of paint is repeatedly applied to the paints used for these purposes or when different kinds of paints are overcoated (hereinafter referred to as "overcoating"), the paint interval is specified and the upper limit period is exceeded. And the adhesiveness is significantly reduced. However, the gap between factory painting and on-site painting has become longer due to the increase in size of structures and construction, and if the prescribed painting interval is exceeded, unplanned work such as surface polishing of the undercoat coating and repainting of the undercoat is required. Will be. In view of such a problem, the present invention does not have an upper limit of the coating interval (hereinafter, "interval free").
The present invention relates to anticorrosion paints for painting steel structures.

[0002]

2. Description of the Related Art Conventionally, solvent-free paints such as nitrified cotton lacquer, acrylic resin paints, vinyl chloride resin paints and chlorinated rubber paints have been known as interval-free paints.
However, these paints are inferior in corrosion resistance as an undercoat, and are rarely used as an undercoat for steel structures. In the coating used as a base coat for anticorrosion, there are restrictions on the coating interval of the oil-based alkyd resin coating for an upper limit of 6 months and the epoxy resin coating for a maximum of 1 month or 3 months. On the other hand, a phenolic resin-based mica-like iron oxide paint (JIS-based) that uses the characteristics of mica-like iron oxide (MIO) as an intermediate coating (long-term durability due to scale-like particles and suitability for top coating due to surface roughness effect) K5554) and epoxy resin mica-like iron oxide paint (JIS-K5555), but there are restrictions on the painting process due to an increase in the number of paintings and man-hours. In particular, there is a demand for interval-free epoxy resin paint, which is the base paint for heavy-duty anti-corrosion paint systems, as steel structures become larger.

[0003]

As described above, the conventionally used interval-free anticorrosion paints have problems such as insufficient anticorrosion property, restriction of topcoating as a coating system, and increase of man-hours for coating. It is practically inadequate as a paint for steel structures. In order to solve such a problem, the present invention provides an interval-free anticorrosive paint for steel structures, which can reduce the number of times of application, has a good anticorrosion property by one application, and can be applied with various topcoats. is there.

[0004]

Means for Solving the Problems The present inventors have been widely used in this field, and started by improving the coating interval of a modified epoxy resin coating having a wide range of suitability for topcoating, and developing an amine-curable epoxy resin. We have discovered an interval-free anticorrosive paint that can be applied with various topcoats by maintaining its anticorrosion property by modifying it with dimer acid. That is, the present invention contains, as a binder resin, an epoxy ester resin having an epoxy equivalent of 400 to 1000 obtained by reacting 20 to 60% by weight of dimer acid with 80 to 40% by weight of a bisphenol type epoxy resin, and a pigment volume concentration ( PVC) is 20 to 50%, which is an anticorrosion paint. In the present invention, when the dimer acid content in the binder resin is less than 20% by weight, the interval-free property is lowered, and when it is more than 60% by weight, the anticorrosion property is significantly lowered. As the dimer acid, both regular type and hydrogenated type can be used. If the epoxy equivalent of the epoxy resin is less than 400, the interval-free property is lowered, and if it is more than 1000, the drying property is lowered. The epoxy resin of the present invention is a usual bisphenol type epoxy resin, for example, Epicoat # 828, # 83.
4, # 1001, # 1002, # 1004 (produced by Yuka Shell Epoxy Co., Ltd.) and the like can be used. Further, amine is suitable as a curing agent for the epoxy resin, and aliphatic polyamine, aromatic polyamine, polyamidoamine and the like can be used. In addition to the above composition, the anticorrosive coating material of the present invention includes titanium oxide, carbon, halo, pigment such as ocher, lead-based pigment,
Chromium-based, phosphoric acid-based, boric acid-based, molybdic acid-based rust-preventive pigments, micaceous iron oxide, scaly pigments such as aluminum and zinc, and / or extenders such as talc, clay, mica and calcium carbonate Pigment volume concentration (PVC) is 20
It can be used in the range of up to 50%. When the pigment volume concentration is less than 20% or more than 50%, the anticorrosion property is deteriorated.

[0005]

【Example】

(Test Examples 1 to 8) To see the relationship between coating composition and quality, Table 1
A paint was prepared with the composition shown in and the quality was confirmed. First, in order to synthesize an epoxy resin as a binder resin, Epicoat # 834 (Epoxy resin manufactured by Yuka Shell Epoxy Co., Ltd., epoxy equivalent 190) and Versadim 216 (Dimmer acid manufactured by Henkel Hakusui Co., Ltd.) are shown in Table 1. An esterification reaction was performed at a ratio shown at 130 to 150 ° C. for 3 to 4 hours to obtain an epoxy ester resin having an epoxy equivalent of 300 to 1500. Using these binder resins, rouge, talc,
It was mixed and dispersed with barium sulfate and xylene to prepare a paint. In addition to this, as a curing agent, Sunamide X2700 (modified polyamidoamine manufactured by Sanwa Chemical Co., Ltd., active hydrogen equivalent 27
0) was added at an epoxy / amine equivalent ratio of 1: 1 and subjected to a performance test. As a result, as shown in Table 1, the paint of Test Example 4, which is an example of the present invention, gave good results in all items.

[0006]

[Table 1]

(Method for preparing test plate) The prepared coating material was applied to a polished soft steel plate by spraying (film thickness 100 μm) and subjected to each test. (* 1) Epoxy resin (Okaka Shell Epoxy Co., Ltd.,
Epoxy equivalent 650) (* 2) Cyclopentadiene (Nippon Zeon Co., Ltd.) (* 3) Bengal (Nippon Bengal Industry Co., Ltd.) (* 4) Talc (Fuji Talc Co., Ltd.) (* 5) ) Barium sulfate (manufactured by Sakai Chemical Co., Ltd.) (* 6) Modified polyamidoamine (manufactured by Sanwa Chemical Co., Ltd.) (* 7) Outdoor exposure (JIS-K5400) After 1, 6 and 9 months, a polyurethane resin coating was applied. Coating (film thickness 25 μm) 7
After being dried for a day, a cross-cut adhesion test (4 mm width) is performed. ◯: 25/25, Δ: 24/25 to 13/25, x: 1
2/25 to 0 (* 8) After drying for 7 days, a cross-cut reaching the substrate is put in the coating film, and a salt spray test is performed for 500 hours to observe the state of the coating film. Rust and blister width of cut part: ○: 2 mm or less, △: 2 to 5 mm, ×: 5 mm (* 9) Curing and drying (20 ° C) ○: Within 8 h, △: 8 to 16 h, ×: 16 h or more

[0008]

According to the present invention, in the anticorrosive coating of steel structures such as bridges, plants, and building steel frames, it is obvious that the type 1 keren is a steel material and that the primer is required to adjust the basis of the type 2 keren depending on the required performance. If it is applied twice, the period until the topcoat is 6
Alkyd resin paints, chlorinated rubber paints, acrylic resin paints, epoxy resin paints, polyurethane resin paints, acrylic silicone resins without any surface adjustment unless special contaminants such as fats and salts are abnormally attached even if they are vacant for more than a month. Various top coats or intermediate coats such as paints and room temperature dry type fluororesin paints can be applied.

Claims (1)

[Claims] 1. An epoxy ester resin having an epoxy equivalent of 400 to 1000 obtained by reacting 20 to 60% by weight of dimer acid with 80 to 40% by weight of a bisphenol type epoxy resin is contained as a binder resin, and a pigment volume concentration ( PVC) is 20 to 50%, an anticorrosion paint.