JPS6112928B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a solvent-free epoxy resin composition having chelate-forming ability. Vehicles traditionally used for paints are
There are a wide variety of resins, including unsaturated fatty acids, alkyds, olefins, diethyls, acrylics, polyesters, epoxys, urethanes, and copolymers thereof. Among them, the demand for epoxy resins is increasing due to their excellent physical properties (adhesion, hardness) and chemical properties (chemical resistance). Furthermore, in recent years, there has been a demand in the market for paints that are non-hazardous, such as those that are low in flammability or non-toxic to the human body. As one of these, so-called solvent-free paints that do not use solvents have been developed. However, corrosion resistance,
Substantially no material with sufficient performance in terms of moisture resistance, physical properties, etc. has been obtained. As one of these improvements, it has been proposed to add heavy metal-based antirust pigments to improve corrosion resistance, but this is not preferred from the viewpoint of pollution. Therefore, it can be said that no pollution-free solvent-based epoxy resin paint has yet been obtained which has performance comparable to or better than conventional paints that use large amounts of organic solvents. On the other hand, polyphenols such as pyrogallol,
Compounds with chelate binding properties, such as phenolcarboxylic acids, chromium complex salts, phthalocyanines, pyridines, and their derivatives, are added to the paint to perform a chelation reaction with the iron surface of the substrate after application, thereby improving the performance of the paint film. Attempts have been made for a long time. That is, solvent-based paints in which tannins were simply added to linseed oil-based resin or drying oil were known for a long time (British Patent Nos. 826,564 and 826,566).
Later, by R.N. Faulkner et al., vegetable oil,
Solvent-based one-component type in which catechol, pyrogallol, gallic acid, or gallic acid ester is covalently introduced into fatty acid ester, alkyd resin, vegetable oil-modified epoxy ester resin, or vegetable oil-modified polyamide epoxy using a catalyst such as a metal alkoxide. paint was developed. These include, for example, UK Patent No. 1045118, US Patent Nos. 3304276 and 3321320, and Oil and Colour.
Journal of the Oil published by Chemists' Association
and Color Chemists′ Association Volume 50, No.
524 pages (1967), etc. Furthermore, British Patent No. 1114400 discloses a composition in which a styrene-allyl alcohol copolymer is reacted with a gallic acid ester. Furthermore, compositions having chelate-forming ability using epoxy resins are also known. For example, 2 which has the ability to form a chelate with the remaining epoxy group by modifying a part of the epoxy group in the epoxy resin with a monobasic fatty acid.
A chelate-forming resin made by reacting a fatty acid derivative having the above-mentioned adjacent phenolic hydroxyl groups and one free carboxyl group (Japanese Patent Publication No. 1973-
2439), is obtained by reacting gallic acid with the residual epoxy group of a reaction product of a polyamide resin with an amine value of 10 or less and an epoxy resin. A composition consisting of an epoxy-polyamide resin having chelate-forming ability and a phosphoric acid compound (Japanese Patent Application Laid-Open No. 17443/1989), which is prepared by reacting a part of the epoxy groups in the epoxy resin with salicylic acid, gallic acid, or esterified products thereof. In addition, epoxy resin, vinyl resin,
One-component or two-component (using amine curing agent) paints diluted with organic solvents containing fluororesins, etc.
48-56228, JP-A-49-122538, JP-A-49-
122597) etc. are known. However, all of these methods use organic solvents, which are not desirable in terms of safety and non-polluting properties. Moreover, all of these are made from modified epoxy resins, which are the main ingredient. In other words, it is a one-component or two-component composition in which all or part of the epoxy groups in the epoxy resin are reacted with a compound that has chelate-forming ability, and therefore the properties of the epoxy resin are significantly reduced. It is known that there are. The present invention relates to a solvent-free epoxy resin composition having chelate-forming ability that overcomes the drawbacks of the prior art. The objects of the present invention are (1) to obtain a coating film that is as good or better than a high molecular weight epoxy resin coating despite the use of a low molecular weight epoxy resin; (2) to provide a coating film that is as good or superior to a high molecular weight epoxy resin coating; To provide a coating composition capable of causing a reaction; (3) To provide a coating composition that provides a coating film with excellent corrosion resistance and moisture resistance; (5) To provide a composition that provides a coating film with excellent rust prevention properties; (5) To provide a composition that is safe to handle and non-polluting because no solvent is used. In addition, the purpose is to improve various chemical or physical properties of the coating film.
It will become clear from the explanation below. That is, the present invention provides (1) a low molecular weight epoxy resin that is liquid at room temperature and has at least two or more epoxy groups in one molecule, and (2) a low molecular weight epoxy resin that has at least two or more nitrogen atoms in one molecule and is bonded thereto. Amine value with active hydrogen
200 or more amino-based curing agent, and one or more of gallic acid, protocatechuic acid, or an alkyl ester thereof (alkyl group having 1 to 12 carbon atoms) in an amount of 5 to 30% by weight based on the curing agent. a curing agent composition that is liquid at room temperature obtained by condensation reaction with a mixture; (3) an epoxy compound having one epoxy group in one molecule of 30% by weight or less based on the epoxy resin; The present invention relates to a solvent-free epoxy resin composition having the following properties. The "low molecular weight epoxy resin that is liquid at room temperature and has at least two or more epoxy groups in one molecule" used in the present invention is, for example, as follows. Examples of bisphenol F-type epoxy resins include commercially available product name XD-7818 manufactured by Dow Chemical Co., Ltd. (average molecular weight approximately 330, hereinafter all indications are the same), and product name XD-7818 manufactured by Dainippon Ink and Chemicals Co., Ltd. Bisphenol A epoxy resins such as the product name Epicron 830 (approximately 330) include the product names Epicort 808 (380 or less), Epikron 815 (approximately 330), and Epikron 815 (approximately 330) manufactured by Ciel Chemical Co., Ltd.
819 (approx. 370), 827 (approx. 370), 828 (approx. 380),
Araldite 834 (approx. 470), Ciba Geigy Co., Ltd. product name Araldite GY-250 (approx. 380), Araldite 252 (approx. 370),
260 (approx. 380), trade name Epicron 840 (approx. 370) manufactured by Dainippon Ink and Chemicals Co., Ltd., product name SB-300 (380 or less) manufactured by Sakamoto Pharmaceutical Co., Ltd., manufactured by Dow Chemical Co., Ltd. Product names DER330 (about 370), DER331 (about 380), DER330 (about 370), DER331 (about 380),
332 (approximately 350), and hydrogenated products of bisphenol A type epoxy resin, such as Epolite 4000 (trade name, approximately 500) manufactured by Kyoei Yushi Co., Ltd. Examples of the phenol novolak type epoxy resin include DEN431 (approximately 350) manufactured by Dow Chemical Co., Ltd. As a polyglycol type epoxy resin, for example, the product name DER736 (approximately 380) manufactured by Dow Chemical Co., Ltd.
Product name Denacol EX-810 manufactured by Nagase Sangyo Co., Ltd. (approx.
220), EX-910 (approximately 240), etc. As a glycidyl ester type epoxy resin,
Product name Epicron manufactured by Dainippon Ink & Chemicals Co., Ltd.
There are 200 (approx. 360) and 400 (approx. 380). The epoxy resin in the present invention also includes a low-viscosity resin having two or more epoxy groups in one molecule. For example, aniline modified epoxy resin,
For example, the product name GAN (approximately 250) manufactured by Nippon Kayaku Co., Ltd.
GOT (approximately 250), glycidyl ether resin of polyol, for example, the trade name Denacol manufactured by Nagase Sangyo Co., Ltd.
EX-314 (approximately 290), alicyclic epoxy resin, such as Chitsonox 221 (trade name, manufactured by Chitso Corporation) (approximately
250), 206 (approximately 140), etc. The epoxy resin of the present invention is liquid at room temperature and has an average molecular weight of about 500 or less. In the composition of the present invention, the viscosity characteristics of the composition,
A diluent is added in an amount of 30% by weight or less to improve workability, coating performance, and coating condition. The diluent is an epoxy compound having one epoxy group in one molecule, such as allyl glycidyl ether, 2-ethylhexyl glycidyl ether, methyl glycidyl ether, butyl glycidyl ether, phenyl glycidyl ether, styrene oxide, cyclohexene oxide, Epichlorohydrin or epoxidized alkylphenol, a compound having one epoxy group obtained by modifying the epoxy resin having two or more epoxy groups in one molecule with a fatty acid or the like, is used. Diluents that do not have an epoxy group in their molecules, such as compounds such as dibutyl phthalate, dioctyl phthalate, tricresyl phosphate, furfuryl alcohol, benzyl alcohol, and pine oil, can also be used. Generally commercially available diluents that do not have epoxy groups in their molecules include Epiclon WT-100 (trade name) manufactured by Dainippon Ink and Chemicals Co., Ltd., EX-50 (trade name) manufactured by Kureha Chemical Co., Ltd.; -1500, manufactured by Mitsubishi Gas Chemical Co., Ltd. under the trade name Nicanol LL, etc. Alternatively, acrylic oligomers such as Aronix M-5700 and M-6100 manufactured by Toagosei Kagaku Kogyo Co., Ltd. can also be used. The epoxy resin of the present invention may optionally contain extender pigments such as talc-precipitated barium sulfate and calcium carbonate, yellow lead, carbon black, titanium oxide, zinc white, red oxide, flaky iron oxide, aluminum powder ultramarine, and phthalocyanine. Coloring pigments such as blue and iron black, glass fibers, glass flakes, mica powder, quartz powder synthetic silica, reinforcing pigments such as asbestos, other thickeners, anti-sagging agents, rust preventive agents or non-polluting rust preventive pigments, antifoaming. agent, wetting agent, suspending agent,
A curing accelerator, a chelation reaction accelerator, etc. can be added. As the rust preventive agent or non-polluting rust preventive pigment,
Examples include conventionally known sodium nitrite, phosphoric acid, ammonium phosphate, zinc phosphate, zinc molybdate, barium metaborate, iron phosphate, and the like. Examples of the curing accelerator include phenol, cresol, nonylphenol, bisphenol A, salicylic acid, resorcinol, hexamethylenetetramine, 2,4,6-tris(dimethylaminomethyl)phenol, and triethylenediamine. Particularly when a tertiary amine is used, it is effective in low temperature curing properties. Examples of the chelation reaction promoter include ferrous chloride, ferric chloride, and organic acids such as acetic acid. Furthermore, in the present invention, other resins can be used in combination with the epoxy resin, preferably at a weight of 20% or less. It is not necessary to react the epoxy groups in the epoxy resin or the amino groups in the curing agent (described later) with the resin used in combination, but it is possible to improve the coating workability of the composition, the coating performance, the surface condition of the coating, etc. Therefore, it is used in combination with addition. Examples include phenolic resin alkyd resin, polyester resin, urethanized oil coal tar, and asphalt. The epoxy resin composition described above or appropriately blended is the main ingredient of the present invention. However, in the present invention, various pigments, additives, or other resins as described above may be mixed in advance with the curing agent composition described below. On the other hand, the "amino curing agent having at least two nitrogen atoms and an active hydrogen bonded to them in one molecule" used in the present invention is a curing agent that is usually used as a curing agent for epoxy resins. These are amino compounds such as amine adducts, polyamides, and polyamines that are liquid at room temperature. The polyamide resin is a condensation of dimer acid (general industrial products contain about 3% monomer acid, about 85% dimer acid, and about 12% trimer acid) and polyamines such as ethylenediamine, diethylenetriamine, or metaphenylenediamine. It is a product. For example, the generally commercially available product names of Sanwa Chemical Industry Co., Ltd. are Sanmide 335, Sanmide 340, and Sanmide 340.
351, product name Tomide 245− manufactured by Fuji Kasei Kogyo Co., Ltd.
There are HS etc. The amine adduct resin is an addition product of ethylene oxide and propylene oxide or the above-mentioned epoxy resin and aliphatic or aromatic polyamines such as ethylene diamine, diethylene triamine or metaphenylene diamine.
For example, commonly available products manufactured by Dainippon Ink Co., Ltd.
Product name: Epotough Hardener 37-611, Lacucamide B-203, Product name: React CA- manufactured by Sanyo Chemical Co., Ltd.
101, trade name Tritex H manufactured by Taiho Kogyo Co., Ltd.
−300, trade name Epicure DX manufactured by Ciel Chemical Co., Ltd.
-103, DX-124, Sanmide X-11P and X-3000 manufactured by Sanwa Chemical Industry Co., Ltd., and the like. Furthermore, amine adduct resins include butyl glycidyl ether, glycidyl ether of versatile acid, glycidyl ester of versatile acid, and addition products of bisphenol type epoxy resins and heterocyclic diamines represented by the following formula. Generally available commercially, Ajinomoto Co., Inc.
There are products such as Epomate B-002 and Epomate C-002. These curing agents may be used singly or as a mixture of two or more depending on the purpose. or,
The polyamines include, for example, diethylenetriamine, triethylenetriamine, xylene diamine,
This includes isoolone diamine, but also phenol-modified polyamine. As the polyamine, for example, Sanwa Kagaku Kogyo, which is generally commercially available,
Product name Sanmide X-963, TX-983 manufactured by Co., Ltd.
Product name: Araldite HY− manufactured by Ciba Geigy Co., Ltd.
837, HY-943, Fujikure X-003, X-003D, and 5000 manufactured by Fuji Kasei Co., Ltd., and Epicure DX-121 manufactured by Ciel Chemical Co., Ltd. These curing agents may be used singly or as a mixture of two or more depending on the purpose. In addition, keteimine is used as a curing agent, and for example, there is a commercially available product such as Epicure H-3 manufactured by Ciel Kagaku Co., Ltd. Since the curing agent performs a crosslinking reaction with the epoxy resin, it is necessary to have at least two or more nitrogen atoms and an active hydrogen bonded to the nitrogen atoms in one molecule. Regarding the curing agent, since a low viscosity curing agent is used without any other limitations, the amine value is 200 or more. However, if the amine value of the curing agent becomes extremely high, there will be a restriction that the pot life after mixing with the epoxy resin as the main ingredient will be shortened. Furthermore, the viscosity of the curing agent also has a large effect on the performance of the paint and the performance of the coating film. Generally, there is a tendency that the higher the viscosity of the curing agent used, the worse the coating workability and the shorter the pot life. It can be improved by adding small amounts of said diluent. The "curing agent composition" as used in the present invention refers to the amino curing agent, gallic acid, protocatekylic acid,
It is a curing agent composition that is liquid at room temperature and is obtained by condensation reaction with one or a mixture of two or more of these alkyl esters (alkyl group having 1 to 12 carbon atoms). Examples of the alkyl esters include esters of the acids and alcohols having 1 to 12 carbon atoms. Examples include methyl gallate, ethyl gallate, propyl gallate, isoamyl gallate, lauryl gallate, ethyl protocatekyate, propyl protocatekyate, and the like. When the composition of the present invention is applied to a steel surface, the phenolic hydroxyl groups contained in gallic acid, protocatechuic acid, or their esters enable a chelation reaction with the base steel surface, giving extremely excellent coating performance. It is possible. The gallic acid, procatechuic acid, or their esters are used in an amount of 5 to 30 weight percent, preferably 10 to 25 weight percent, based on the solid content of the amino curing agent. If the amount of the compound having chelate-forming ability in the above ratio is less than 5% by weight, the desired effects of the present invention cannot be expected to be very good. On the other hand, if the amount exceeds 30% by weight, more chelate than necessary is formed, resulting in a hard and brittle coating film, which also reduces moisture resistance and is uneconomical, which is undesirable. In the present invention, the reaction between gallic acid, protocatechuic acid, or their esters and the amino curing agent is carried out, for example, by the following method. That is, gallic acid, protocatechuic acid, or their ester acids and the amino curing agent were mixed together at 100%
The mixture is heated and stirred at any temperature up to 240° C. in the presence of an inert gas such as nitrogen gas or under reduced pressure until the desired condensed water or alcohol is obtained (usually 2 to 10 hours). In the case of the condensation reaction of gallic acid or protocatechuic acid with alkyl esters, a catalyst such as a metal alcoholate may be added. Thus, a curing agent composition is obtained in which gallic acid, protocatechuic acid, or their esters are covalently incorporated into the curing agent. The curing agent composition of the present invention as described above has the ability to perform a crosslinking reaction with the epoxy resin, that is, to play the role of a curing agent, and also to perform a chelation reaction with the iron surface of the object to be coated. That is, when applied as a coating composition onto a steel surface, the curing agent composition enables a chelation reaction with the steel surface, regardless of the condition of the steel surface and the degree of rust generation, and is particularly effective in preventing rust. Even without adding pigments or the like, coating film performance such as water resistance, humidity resistance, salt water immersion resistance, salt water spray resistance, etc. is significantly improved. Furthermore, in the present invention, 2 to 30% by weight of tannins may be mixed with the curing agent composition to increase the chelate formation ability. In the present invention, a main component mainly composed of an epoxy resin and a curing agent composition are used in combination. The mixing ratio is (sum of epoxy groups in the epoxy resin and epoxy groups in the epoxy compound)/(active hydrogen bonded to nitrogen atoms in the curing agent composition) 1/
It is preferable to mix at a ratio of 2 to 2/1. Since the composition of the present invention mixed at the time of use reacts and becomes solid if left for a long time, it is desirable to apply the composition immediately after mixing. The composition of the present invention forms a coating film on the object to be coated by drying at room temperature or heating by common methods such as brush coating, air spray coating, airless coating, and roll coater coating. The object to be coated is preferably a steel material such as mild steel or hard steel, such as degreased surfaces, chemical conversion treated surfaces, rusted surfaces, wet surfaces,
It can also be applied to welded parts. It is also possible to coat on nonferrous materials such as galvanized plates, tin plated plates, aluminum plates, and steel plates, as well as on shot primers (for example, wash primers, zinc-rich primers, etc.) and various undercoat coatings. Further, a conventional top coat may be applied on the coating film for aesthetic purposes or other purposes. As the top coat, for example, vinyl resin paint,
Examples include chlorinated rubber paints, urethane resin paints, silicone resin paints, acrylic resin paints, fluorine resin paints, alkyd resin paints, epoxy resin paints, etc.; It is necessary to select The composition of the present invention can also be utilized for adhesives, putty, etc. by making the most of its characteristics. Thus, according to the composition of the present invention, it is possible to form a coating film with excellent performance even without the use of any particular rust-preventing pigment. Therefore, it is a solvent-free resin that has extremely low risk of fire, etc., is non-polluting, resource-saving paint, and has significantly improved corrosion resistance such as moisture resistance, salt water immersion resistance, and salt water spray resistance. Since a composition can be obtained, it can be said that its industrial significance is extremely large. The details of the present invention will be explained below with reference to Examples. "Part" or "%" means "part by weight" or "% by weight"
It is shown with. Example 1 Allylglycidyl as an epoxy compound having one epoxy group in one molecule was added to 450 parts of aniline-modified epoxy resin [manufactured by Nippon Kayaku Co., Ltd., trade name GOT, epoxy equivalent weight 115 to 135, average molecular weight about 250]. 50 parts of ether, 200 parts of talc, precipitated barium sulfate
350 parts were added and kneaded with a roller to form a main ingredient. On the other hand, 1000 parts of polyamide resin [manufactured by Sanwa Kagaku Kogyo Co., Ltd., trade name Sanmide 335, amine value 450 ± 20],
A curing agent composition having chelate-forming ability was prepared by reacting 100 parts of gallic acid in the presence of an inert gas at a temperature of 140 to 150°C until a predetermined amount of condensed water was obtained. Mixing the main agent and a curing agent composition having chelate-forming ability in a ratio of 100/45 (weight ratio),
An epoxy resin composition having chelate-forming ability of the present invention was obtained. The composition was applied to a rusted steel plate (approximately 16. x 50 x 150 mm: grade 2 scratching) polished with waterproof abrasive paper (#80) using an airless sprayer to a film thickness of 100 ± 15 microns. Painted. Then, it was air-dried in a constant temperature room (20°C, 75% RH) for 7 days, and a performance test was conducted. The coating film property test results are shown in the table along with the examples below.
They are summarized in 1. Example 2 Butyl as an epoxy compound having one epoxy group in one molecule was added to 450 parts of bisphenol F type epoxy resin [manufactured by Dow Chemical Co., trade name: XD-7818, epoxy equivalent weight 165, average molecular weight about 330]. 50 parts of glycidyl ether, 200 parts of talc, and 350 parts of precipitated barium sulfate were added and kneaded with a roller to form a main ingredient. On the other hand, using 1000 parts of polyamide resin [manufactured by Fuji Kasei Co., Ltd., Fujikyure 245-HS, amine value 400±20] and 150 parts of gallic acid, the same procedure as in Example 1 was carried out.
A curing agent composition having chelate-forming ability was obtained. Mixing the main agent and a curing agent composition having chelate-forming ability in a ratio of 100/80 (weight ratio),
An epoxy resin composition having chelate-forming ability of the present invention was obtained. Table 1 shows the performance test results of a coating film obtained using the composition in the same manner as in Example 1. Example 3 Bisphenol A type epoxy resin [Ciel Chemical Co., Ltd.
Manufactured by Co., Ltd., trade name: Epicote 827, epoxy equivalent: 185,
Average molecular weight: approx. 370] 150 parts, polyol glycidyl ether resin (manufactured by Nagase Sangyo Co., Ltd., trade name, Denacol EX-314, epoxy equivalent: 145, average molecular weight: approx.
Add 100 parts of phenyl glycidyl ether [epoxy equivalent 150] to 100 parts of 290], adjust the viscosity, add 200 parts of talc, 250 parts of precipitated barium sulfate, and 100 parts of red iron sulfate, and knead with a roller to form the main ingredient. And so. On the other hand, chelate formation ability was obtained by using 1000 parts of amine duct resin [manufactured by Dainippon Ink and Chemicals Co., Ltd., trade name Epotough Hardener 37-611, amine value 340±10] and 200 parts of gallic acid in the same manner as in Example 1. A curing agent composition was obtained. The base resin and the curing agent combination having chelate-forming ability were mixed in a ratio of 100/40 (weight ratio) to obtain an epoxy resin composition having chelate-forming ability of the present invention. Table 1 shows the test results of a coating film obtained using the composition in the same manner as in Example 1. Example 4 180 parts of bisphenol F type epoxy resin [same as Example 2], 20 parts of polyglycol type epoxy resin [manufactured by Dow Chemical Co., trade name DER736, epoxy equivalent weight 175 to 205, average molecular weight about 380] , alicyclic epoxy resin [manufactured by Chitsuso Co., Ltd., trade name, Chitsusonox 206, epoxy equivalent weight 74-78, average molecular weight approx.
140] Add 50 parts of phenyl glycidyl ether as an epoxy compound having one epoxy group in one molecule, 150 parts of talc, 200 parts of precipitated barium sulfate, and 100 parts of red iron to a resin component consisting of 250 parts,
The mixture was kneaded with a roller to form the main ingredient. On the other hand, amine adduct resin [manufactured by Sanwa Kagaku Co., Ltd., trade name, Sanmide x 3000, amine value 500 ± 30] 500
50 parts of gallic acid and 100 parts of protocatechuic acid were added to 500 parts of polyamide resin [same as in Example 1], and the same procedure as in Example 1 was performed to obtain a curing agent composition having chelate-forming ability. The base resin and a curing agent composition having chelate-forming ability were mixed in a ratio of 100/75 (weight ratio) to obtain an epoxy resin composition having chelate-forming ability of the present invention. Table 1 shows the performance test results of a coating film obtained using the composition in the same manner as in Example 1. Example 5 320 parts of bisphenol F type epoxy resin [same as Example 2] and novolak type epoxy resin [Dow Chemical Co., Ltd. trade name, DEN-431, epoxy equivalent weight 172 to 179, average molecular weight about 350] 300 50 parts of allyl glycidyl ether as an epoxy compound having one epoxy group in one molecule and 100 parts of a diluent without an epoxy group [manufactured by Dainippon Ink & Chemicals Co., Ltd., trade name, Epiclon WT100] were added to Dissolved and adjusted viscosity, 180 parts of talc, 250 parts of precipitated barium sulfate, 100 parts of red iron phosphate, zinc phosphate.
20 parts were added and kneaded with a roller to form a main ingredient. On the other hand, phenol-modified polyamine [Sanwa Kagaku Co., Ltd.]
Manufactured by, product name, Sunmide x 963, amine value 570±
30] 1000 parts of n-propyl gallate was added to 150 parts of n-propyl gallate and 2 parts of sodium ethylate, and under the same reaction conditions as in Example 1, a curing agent composition having chelate-forming ability was obtained. The base resin and the curing agent composition having chelate-forming ability were mixed in a ratio of 100/20 (weight ratio) to obtain the epoxy resin composition having chelate-forming ability of the present invention. Table 1 shows the performance test results of the coating film obtained by coating and drying the composition in the same manner as in Example 1. Comparative Example 1 The base material prepared in Example 1 was used. As a curing agent, polyamide resin Sanmide 335 (same as in Example 1) was used as it was without reacting it with gallic acid. The base resin and curing agent were mixed at a ratio of 100/41 (weight ratio). The composition was coated and dried in exactly the same manner as in Example 1. The performance test results of the obtained coating film are shown in Table-1. Comparative Example 2 The base material prepared in Example 2 was used. The curing agent is polyamide resin Fujikure-245-
HS (same as in Example 2) was used as is without reacting with gallic acid. The base material and curing agent were mixed at a ratio of 100/68 (weight ratio). The composition was coated and dried in the same manner as in Example 1. The performance test results of the obtained coating film are shown below.
Shown in 1. Comparative Example 3 The base material prepared in Example 3 was used. The hardening agent is amine adduct resin Epotough hardener.
37-611 (same as Example 3) was used as is without modification. The base material and curing agent were mixed at a ratio of 100/32 (weight ratio). The composition was coated and dried in the same manner as in Example 1. The performance test results of the obtained coating film are shown below.
Shown in 1. Comparative Example 4 The base material prepared in Example 4 was used. On the other hand, as a curing agent, the amine adduct resin Sanmide x3000 used in Example 4 was used without being modified with gallic acid and protocatechuic acid. 500 parts of this amine adduct resin and 500 parts of the resin curing agent used in Comparative Example 1 were mixed to prepare a curing agent for this comparative example. The base material and curing agent were mixed at a ratio of 100/64 (weight ratio). A coating film was prepared using the composition in the same manner as in Example 1. The performance test results of the obtained coating film are shown in Table-1. Comparative Example 5 The base material prepared in Example 5 was used.
As a curing agent, a phenol-modified polyamine (same as in Example 5) was used as it was without being modified with n-propyl gallate. The base material and curing agent were mixed at a ratio of 100/17 (weight ratio). A coating film was prepared using the composition in the same manner as in Example 1. The performance test results of the obtained coating film are shown in Table-1.

【table】

[Table] From the test results table, it is clearly seen that the coating film obtained from the composition of the present invention has extremely excellent performance in salt water spray resistance, moisture resistance, water resistance, and salt water immersion resistance.

Claims (1)

[Scope of Claims] 1. (a) A low molecular weight epoxy resin that is liquid at room temperature and has at least two or more epoxy groups in one molecule, (b) (a) At least two or more nitrogen atoms in one molecule, and an amino-based curing agent having an amine value of 200 or more and having an active hydrogen bonded thereto; The number of carbon atoms in the group is 1 to 12)
(c) An epoxy resin having one epoxy group in one molecule of 30% by weight or less based on the above epoxy resin; A solvent-free epoxy resin composition having chelate-forming ability consisting of a compound.