JPS61152774A - Corrosion-resistant coating compound composition - Google Patents

Abstract

PURPOSE:The titled composition stabilizing rust, preventing corrosion in the interior of steel ships, capable of showing improved corrosion-resistant effect for a long period by a simple substrate regulation, comprising a specific modified epoxy resin, a bituminous substance, and zinc chromate as essential components. CONSTITUTION:The aimed composition comprising (A) a high-molecular weight reaction product (=modified epoxy resin) obtained by reacting (i) an epoxy resin shown by the formula (R1 is H, or CH3; R2 is -CH2-, or group shown by the formula II; n is 5-30) with a neighboring OH group-containing polyhydric phenol carboxylic acid, a neighboring OH group-containing polyhydric phenol, a polyhydric alcohol ester, or a neighboring hydroxyl group-containing polynucleus polyhydric phenol in a solvent, (B) a bituminous substance (e.g., coal tar pitch, etc.), and (C) zinc chromate as essential components.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention is directed to low-base conditioning for preventing corrosion of the interior of steel vessels, such as ballast tanks, void spaces, coffer dams, holds, chain lockers, etc. The present invention relates to anticorrosion coating compositions for molds.

(Prior art) Anticorrosion paints are used for corrosion protection inside ships, and are mainly composed of epoxy resins, urethane resins, vinyl resins, chlorinated rubber resins, bituminous substances, and pigments. These paints are water resistant and salt water resistant. , has excellent corrosion resistance and is widely used.

(Problems to be Solved by the Invention) However, in order to exhibit sufficient performance, careful preparation of the substrate, such as sandblasting, 5IsSa-15 or Pa'7-2 treatment, 5ISSt-3, etc., is necessary. Furthermore, the interior of a ship has a complex structure and poor footing, and scaffolding is sometimes necessary to ensure work safety.The careful preparation of the surface described above requires a great deal of academic ability, time, and expense. What is needed is the actual situation.

Grease-like non-drying anti-corrosion paints are paints that can be applied with simple preparation of the substrate, but they are not widely used because the paint film remains soft and easily damaged.

An object of the present invention is to provide an anticorrosion paint that can exhibit excellent anticorrosion effects over a long period of time with simple substrate preparation.

Another object of the present invention is to greatly reduce the process of preparing the substrate.

(Means for Solving the Problems) The polyhydric phenol-modified epoxy resin having adjacent hydroxyl groups used in the anticorrosion paint of the present invention can be used to prevent corrosion caused by iron hydroxide, iron oxide, etc., generated on the surface of the steel material to be coated. penetrates into
A chelate is formed with the rust to stabilize the rust and at the same time inhibit the progress of the rust.The state of this chelate formation is shown in Equation-1.

Formula-1 P: Indicates an epoxy resin skeleton.

The polyhydric phenol group having adjacent hydroxyl groups in the modified epoxy resin has reducing properties, and also has the effect of converting red rust into stable black rust as shown in Formula 2.

Formula-2 Fe00H phenol group Fe5Q6 (red rust) (black rust) In order to bond a polyhydric phenol group having adjacent hydroxyl groups to an epoxy resin, a polyhydric phenol polyhydric alcohol ester having adjacent hydroxyl groups or (andlor) adjacent hydroxyl groups A condensate of polyhydric phenol and formalin is reacted with an epoxy resin in a solution. Examples of polyhydric phenol polyhydric alcohol esters having adjacent hydroxyl groups include ethylene glycol, flopylene glycol, butylene glycol, and 1,6-hexane. Diols, glycerin, trimethylolpropane, pentaerythritol, sorbitol, polyhydric alcohols such as glucose, catechol-3-carboxylic acid, catechol-4-carboxylic acid, gallic acid, m-digallic acid, pyro, gallol-4- Any combination of ester compounds with polyhydric phenol carboxylic acids such as carboxylic acid, pyrogallol-4,6-dicarboxylic acid, and tannic acid can be used; however, when these are reacted with an epoxy resin, salicylic acid ester, p - Mononuclear phenol carboxylic acid ester such as hydroxybenzoic acid ester may be mixed.

Examples of polynuclear polyhydric phenol compounds having adjacent hydroxyl groups include catechol, catechol-3 (or 4)-carboxylic acid (or its ester), pyrogallol, pyrogallol-4-carboxylic acid (matahazonoester), pyrogallol-4,s -Dicarboxylic acid (or its ester)
, 3.4.5-toIJ oxybenzoic acid (or its ester), tannic acid (or its ester), urushiol, and other formalin condensates are used. Also, when polyhydric phenol is condensed with formalin, phenol,
Mononuclear phenols such as cresol, hydroquinone, and salicylic acid may be mixed.

As the above-mentioned modified epoxy resin having chelate-forming ability, for example, Adeka Resin EPX-881 manufactured by Asahi Denka Kogyo ■
(Product name) can be used 0 It is necessary to use a bituminous substance in combination to improve waterproofness, and 30 to 600 parts, preferably 60 to 400 parts, are mixed with 100 parts of modified epoxy resin. It is appropriate to use. When the amount is less than 30 parts, sufficient waterproofness cannot be obtained, and conversely, when it is more than 600 parts, the chelate formation of the modified epoxy resin becomes insufficient.

There are two types of bituminous substances: those made from coal and those made from petroleum, but it is necessary to select them based on properties such as waterproofness, hardness, and cohesive strength.0 When coal is carbonized, it produces aromatic substances. A distillate mainly consisting of these compounds can be obtained, but at 300-360℃
The distillate above 360℃ is called coal tar, and the distillate above 360°C is called coal tar pitch. Coal tar pitch is further classified into soft, medium, and hard depending on the softening point. 0 Waterproofing is called hard coal tar pitch, which is a polymer. is the best, but since it is brittle, in practice a small amount of coal tar is mixed with coal tar pitch to balance waterproofness and physical properties. Coal tar is essential as a plasticizer for coal tar pitch, although it can cause pluming. There is also so-called swollen coal, which is made by swelling coal powder with a coal tar/coal tar pitch mixture at a high temperature of 300° C. or higher, and has the best waterproof properties. This material has excellent cohesive strength in spite of its high softening point. Petroleum-based bituminous materials used in the present invention include asphalts. It is mainly composed of aliphatic polymeric substances, and has superior caking properties and flexibility compared to coal-based bituminous substances, but is slightly less waterproof. Therefore,
When using asphalt, it is preferable to use it together with a coal-based bituminous material.

Asphalts include Gilt Night, Glance Pitch,
There are petroleum asphalts obtained from petroleum refining residues such as natural asphalts such as grahamatite, straight asphalt, and Plow 7 asphalt obtained by oxidative polymerization of straight asphalt at high temperatures.

The bituminous material used in the present invention has a softening point of 50 to 60.
Soft material containing 5-20% (weight) of coal tar at °C
Medium pitch is suitable as it has a good balance of waterproofness and flexibility. In the case of swelling charcoal, it is preferable to have a softening point of about 60 to 70° C., since it has excellent flexibility despite being hard. Although asphalt improves the flexibility of pitch, it reduces waterproofness, so it is preferable to use it in an amount of 50% or less (by weight) of the total amount of bituminous material. When using dotted bituminous materials, a small amount of liquid synthetic rubber can also be used in combination to improve flexibility.

The anticorrosive coating composition using a mixture of a modified epoxy resin and a bituminous substance as a color vehicle has the disadvantage that drying is slow at the initial stage of coating. Furthermore, the polyhydric phenol groups contained in the modified epoxy resin are highly hydrophilic, and most of the polyhydric phenol groups that do not come into contact with the rusted surface tend to reduce the water resistance of the coating film. Bituminous substances are used in combination to improve water resistance, but if used too much, the original function of the modified epoxy resin, that is, the function of stabilizing rust through chelate formation, is reduced. Mixing of extender pigments is effective in improving drying performance, but as the amount of cross-polishing increases, the permeability of water and salts to the coating film increases, which combined with the hydrophilicity of non-chelated polyhydric phenol groups improves corrosion resistance. is on the decline. Although the balance can be achieved by adjusting the composition ratios of the modified epoxy resin, bituminous substance, and extender pigment, both drying properties and anticorrosion properties have to be sacrificed to some extent. As a result of intensive investigation into methods for simultaneously improving these conflicting performances, it was found that increasing the amount of zinc chromate shows a dramatic effect. Such an effect of zero zinc chromate is presumed to be a direct result. That is, since the viscosity of the composition increases due to the addition of zinc chromate, the zinc chromate and the modified epoxy resin react, reducing the hydrophilicity of the polyhydric phenol groups that do not participate in chelate formation, thereby improving the water resistance of the coating film. Zinc chromate improves drying properties due to a certain cross-linking effect of the modified epoxy resin, and zinc chromate is also effective as an anticorrosion pigment, and has the above-mentioned effect of improving water resistance and chelate formation of modified epoxy resin. This is thought to improve corrosion resistance in combination with the rust stabilizing effect caused by oxidation.

The appropriate cooling amount of zinc chromate (hereinafter expressed in parts by weight) is 2 to 40 parts, preferably 5 to 30 parts, based on 100 parts of the solid content of the modified epoxy resin.The effect is significant when the amount is 0.2 parts or less. However, if the amount is 40 parts or more, the increase in viscosity will be too rapid and large, which is not preferable. 2 to 15 more
In the range of 15 to 40 parts, the viscosity increase is gradual and small, so the composition can be made into a one-component type, while in the range of 15 to 40 parts, the solid content of the composition is reduced or the modified epoxy resin component and zinc chromate component are combined. It is desirable to use a two-liquid type with the two components separated. Commercially available zinc chromates include the ZTO type, which has the chemical formula ZnCrO4.4 Zn (OH), and the chemical formula KIO.4ZnO.4CrOH.3.
There are two types of zPC type represented by H10. Since the latter has higher solubility in water than the former, it is generally
O type is mainly used. In the present invention, both exhibit similar effects, and the zTO type.

Although the ZPC type can be used alone or in combination, it is most preferable to use the ZTO type alone for the reasons mentioned above.

Talc, mica, barium sulfate, calcium carbonate, etc. can be used as extender pigments, and if necessary, coloring pigments such as Bengara, anti-sagging agents, anti-settling agents, etc. can be mixed as appropriate. Furthermore, an anticorrosive pigment other than zinc chromate may be used in combination.The anticorrosive paint is prepared by combining the above-mentioned composition with a solvent, such as an aromatic solvent such as doluol, kijirole, or solvent naphtha, or a ketone solvent such as MEK, MIBK% cyclohexanone. , n-propyl alcohol, 1s
o-7” lopyl alcohol, n-butanol, iao
Alcohol solvents such as 7'f alcohol, ester solvents such as ethyl acetate, butyl acetate, and ethylene glycol monoacetate, cellosolve solvents such as ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, and ethylene glycol monobutyl ether acetate. After mixing and dispersing with a teaser together with at least two selected from among the above,
It can be adjusted by kneading with a dispersing device such as a three-piece CI −/l/, a ball mill, or a sand grind mill, and
1. It can be coated by ordinary coating means such as Row 5-coating D, air spray, and airless spray.

When using a large amount of zinc chromate to create a two-component type, it is necessary to separately adjust the component containing zinc chromate and the component containing modified epoxy resin, but the mixing ratio, composition, and viscosity of both components are free. It can be adjusted to

In addition to the interior of steel ships mentioned above, it is also used as an anticorrosion coating for oil storage tanks, various land-based plants, the inner surfaces of bridge girders, and other low-base prepared surfaces of steel structures.

(Effects of the Invention) ■ The polyhydric phenol group having adjacent hydroxyl groups in the modified epoxy resin reacts with rust, forms a chelate, and stabilizes the rust.

■ The polyhydric phenol group having adjacent hydroxyl groups in the modified epoxy resin has reducing properties and also has the effect of converting red rust into stable black rust.

■ The bituminous substance used in combination with modified epoxy resin has excellent waterproof properties and improves the water resistance and water resistance of the coating film.

■ Zinc chromate reacts with free polyhydric phenol groups that did not participate in chelate formation, improving the water resistance and drying properties of the coating film. ■ Zinc chromate is also effective as an anticorrosion pigment, improving corrosion resistance.

■ Due to the mutual effects of the above ■, ■, ■, ■, ■, long-term corrosion protection is possible even with simple substrate preparation0 (Example) Examples of the present invention are shown in Table-1, and performance test results are shown in Table-1. Note 1: Modified epoxy resin, solid content 54%, manufactured by Jiryuka Kogyo Co., Ltd. Note 2: Softening point 70-80°C , tar oil/medium pitch=1
5/85 Solid content 80%, doluol liquid Note 32 Nippon Inorganic Chemical Co., Ltd. Note 4: Organic bentonite thixotropic agent, NL Chemical Co., Ltd. Note 5: Toluol: cyclohexanone: ethyl cellosolve = 50:30:20 The performance of the compositions of Examples prepared by mixing and dispersing using a three-roll machine was evaluated in the following manner, along with Comparative Examples.

(1) Preparation of test plate A polished mild steel plate with a size of 1.6 x 70 x 150 was soaked in 3% saline solution and exposed outdoors for 3 days to develop rust. This process is repeated 10 times to obtain a rusted steel plate. This rusted steel plate is removed with a disc sundae and 5xss
The degree of rust removal was adjusted to two types: t-a (careful rust removal) and 5ISSt-1 (simple rust removal).

Next, paints with the compositions of Examples and Comparative Examples were applied to the above two types of rust removal test plates with a brush to a dry film thickness of 200 microns, and dried indoors for 7 days to form the test plates. did.

(2) Evaluation method a: Drying property After drying at -25° C. for 2 days after application, the degree of fingerprint adhesion is visually determined by pressing strongly with a finger.

b: Appearance of paint film - Visually judge the degree of blistering, cracking, expansion, etc.

C: Adhesiveness - Cut the sections that reach the substrate at 2 txm intervals, peel off rapidly with adhesive tape, and count the number of remaining sections.

d: Salt water resistance - After being immersed in 3% saline solution at room temperature for 3 months, the appearance and adhesion of the coating film are examined.

e: High humidity resistance After testing for 14 days at -50°C and 95% relative humidity, the appearance and adhesion of the coating film are examined.

Claims (5)

[Claims] (1) (A) General formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (However, R_1; H or CH_3, R_2; -CH_2- or ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ n; 5 to 30) A high molecular weight reaction obtained by reacting the represented epoxy resin with a polyhydric phenol carboxylic acid having adjacent hydroxyl groups, a polyhydric phenol having adjacent hydroxyl groups, a polyhydric alcohol ester, or a polynuclear polyhydric phenol having adjacent hydroxyl groups in a solvent. An anticorrosive paint composition containing a product (hereinafter referred to as "modified epoxy resin"), (b) a bituminous substance, and (c) zinc chromate as essential components. (2) In claim 1, the polyhydric phenol polyhydric alcohol ester having adjacent hydroxyl groups includes ethylene glycol, propylene glycol, butylene glycol, 1,6-hexanediol, glycerin, trimethylolpropane, pentaerythritol, Polyhydric alcohols such as sorbitol and glucose, and catechol-3-
Carboxylic acid, catechol-4-carboxylic acid, gallic acid,
An anticorrosive coating composition characterized in that it is an ester compound of any combination of m-digallic acid, pyrogallol-4-carboxylic acid, pyrogallol-4,6-dicarboxylic acid, and tannic acid with a polyhydric phenol carboxylic acid. (3) In claim 1, the polynuclear polyhydric phenol having adjacent hydroxyl groups is catechol, catechol-
3 (or 4)-carboxylic acid (or ester thereof), pyrogallol, pyrogallol-4-carboxylic acid (or ester thereof), pyrogallol-4,6-dicarboxylic acid (or ester thereof), 3,4,5 - An anticorrosive paint composition characterized by being a formalin condensate of trioxybenzoic acid (or its ester), tannic acid (or its ester), and urushiol. (4) In claim 1, the bituminous material is
Coal tar pitch, a mixture of coal tar and coal tar pitch, heavy materials obtained from coal such as swollen coal obtained by heat treating coal powder with coal tar or a mixture of coal tar and coal tar pitch, and petroleum. An anticorrosive paint characterized by being made by mixing at least one selected from straight asphalt, blown asphalt obtained by oxidative polymerization of straight asphalt at high temperatures, and naturally occurring natural asphalt with a modified epoxy resin. Composition. (5) In claim 1, 2 parts by weight of zinc chromate is added to 100 parts by weight of the solid content of the modified epoxy resin.
An anticorrosive paint composition characterized in that it is formed by mixing ~40 parts by weight.