JP2011094104A - Epoxy resin composition and coating composition containing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an epoxy resin composition which can form a coating film having excellent initial drying property without damaging its finish, and can be diluted easily using a weak solvent such as mineral spirit, thereby offering greater freedom in the selection of solvent. <P>SOLUTION: The epoxy resin composition includes a modified epoxy resin (I) having an epoxy resin obtained by reacting an epoxy resin (a) which has at least two epoxy groups in one molecule, rosins (b), an aliphatic acid (c), a polyisocyanate compound (d), and an amine curing agent (II). <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an epoxy resin composition and a coating composition containing the same.

  Epoxy resins have been widely used in various fields such as paints, adhesives, and sealants because of their excellent adhesion to the base. For example, in the field of anticorrosion paints, epoxy resins are the main ingredients and polyamines are used. The development of paints that contain curing agents is ongoing.

  In the field of such anticorrosive coatings, the use of a fatty acid-modified epoxy resin to which a fatty acid or the like is added as the epoxy resin to be used achieves both stress relaxation and anticorrosive properties of the coating film.

  On the other hand, in recent years, there has been a demand for the development of paints that can be dissolved in organic solvents that have a high flash point such as mineral spirits, a high boiling point, and a relatively low environmental load, so-called weak solvents. In the field of anticorrosion paint containing a curing agent, there is an increasing demand for a weak solvent.

  In order to meet this demand, Patent Documents 1 and 2 propose a method for producing a modified epoxy resin by reacting an epoxy resin with an aliphatic monocarboxylic acid, a diisocyanate compound, or an alkylphenol.

  The modified epoxy resin obtained by this method can be dissolved or stably dispersed in a weak solvent. However, since the amount of modification is large, the drying property of the coating film and the physical properties of the coating film are insufficient, or the paint Since the viscosity is high, there is a problem in coating workability and finish, and there is a drawback that it is necessary to design a large amount of organic solvent contained in the paint.

  In order to improve such drawbacks, Patent Document 3 proposes a modified epoxy resin using a specific aliphatic monocarboxylic acid and having a specific range of the amount of modification of the aliphatic monocarboxylic acid and isocyanate. .

  Such a modified epoxy resin has good solubility in mineral spirits, and a paint containing the modified epoxy resin can achieve high solidification and performance such as coating film properties is good, but initial drying at room temperature. There is still room for improvement in terms of sex.

  By the way, if the molecular weight of the modified epoxy resin is designed to be high in order to improve the initial drying property at room temperature, the solubility in weak solvents decreases, and the paint viscosity increases as the resin viscosity increases. In addition, there arises a problem that the finish is deteriorated. Therefore, it is very difficult to design a modified epoxy resin with improved initial drying properties without impairing the solubility or finish in a weak solvent.

Japanese Patent Laid-Open No. 3-115318 JP-A-4-39320 JP-A-9-143246

  An object of the present invention is an epoxy resin that can form a coating film with good initial drying properties without impairing the finish, and can be easily diluted with a weak solvent such as mineral spirit, and has a wide selection of solvents. It is to provide a composition.

  As a result of intensive studies to achieve the above object, the present inventors have used rosins, fatty acids and polyisocyanate compounds as modifiers for the modified epoxy resin, and combined the resulting modified epoxy resin with an amine curing agent. And the use of the epoxy resin composition, it has been found that an epoxy resin composition having a wide choice of solvent and an improved initial drying property of the coating film can be obtained, and the present invention has been completed.

Thus, the present invention
(I) Modification having an epoxy group obtained by reacting an epoxy resin (a) having at least two epoxy groups in one molecule, a rosin (b), a fatty acid (c) and a polyisocyanate compound (d) An epoxy resin composition comprising an epoxy resin and (II) an amine curing agent is provided.

  The present invention also provides a coating composition containing the above epoxy resin composition.

  The present invention further provides a coating method characterized by coating the above-described coating composition.

  The epoxy resin composition according to the present invention can be easily diluted even with a weak solvent such as mineral spirit, so the degree of freedom in selecting the solvent is wide, and the coating composition containing the epoxy resin composition is excellent in coating workability and formed. The coated film is excellent in the initial drying property and has a good finish.

  Hereinafter, the epoxy resin composition of the present invention and the coating composition containing the same will be described in more detail.

  The epoxy resin composition of the present invention comprises a modified epoxy resin (I) and an amine curing agent (II).

Modified epoxy resin (I) :
The modified epoxy resin (I) used in the present invention comprises an epoxy resin (a) having at least two epoxy groups in one molecule, a rosin (b), a fatty acid (c) and a polyisocyanate compound (d). It is a resin obtained by reacting.

Epoxy resin (a) :
Examples of the epoxy resin (a) having at least two epoxy groups in one molecule include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AD type epoxy resin, and the like. , DER-331J (trade name, manufactured by Dow Chemical Co., Ltd.), JER828, 834, 806 (above trade name, manufactured by Japan Epoxy Resin Co., Ltd.), GY # 260 (trade name, manufactured by Asahi Ciba), Epomic R # 140P (product) Name, manufactured by Mitsui Petrochemical Co., Ltd.) and Epototo YD128 (trade name, manufactured by Toto Kasei Co., Ltd.) can be used.

  As an epoxy resin (a), the solubility with respect to weak solvents, such as a mineral spirit, improves, and generally the selectivity of the organic solvent which can be used becomes 300 or less, Especially within the range of 160-260. Preferred are those having an epoxy equivalent weight and generally a number average molecular weight in the range of 1000 or less, in particular 380 to 600.

  Here, the “weak solvent” generally means a solvent having a weak dissolving power, and is not strictly distinguished, for example, a boiling point selected from an aliphatic hydrocarbon solvent and an aromatic hydrocarbon solvent. Includes hydrocarbon solvents having a temperature of 148 ° C. or higher. Examples of the weak solvent include mineral spirit, white spirit, mineral turpentine, isoparaffin, solvent kerosene, aromatic naphtha, VM & P naphtha, solvent naphtha, and the like. "Solvesso 150", "Solvesso 200", "Essonaphtha No. 6" (trade name, manufactured by Esso Oil Co., Ltd.); 100 ”(trade name, manufactured by Idemitsu Kosan Co., Ltd.);“ HAWS ”,“ LAWS ”(trade name, manufactured by Shell Chemicals Japan Co., Ltd.);“ A Solvent ”(trade name, manufactured by Nippon Oil Co., Ltd.) It is done.

In the present specification, the “epoxy equivalent” is the mass (g) of resin (solid content) per gram equivalent of epoxy group, and can be measured as follows in accordance with JIS K7236 (1995):
A sample is dissolved in chloroform and acetic acid, 10 ml of a solution obtained by dissolving 100 g of tetraethylammonium bromide in 400 ml of acetic acid is added to the solution, titrated with a perchloric acid acetic acid solution using crystal violet as an indicator, and the following formula is calculated.

Epoxy equivalent (g / eq) = 1000 × m / (C × V)

m: Sample solid content mass (g),
C: concentration of perchloric acid acetic acid in the titrant,
V: Titration amount.

  In addition, the “number average molecular weight” of the epoxy resin can be obtained by converting the number average molecular weight of the sample measured by gel permeation chromatography using the number average molecular weight of polystyrene as a reference, using tetrahydrofuran as a solvent. .

Rosin (b) :
The rosins (b) are residual resins mainly composed of resin acids after distilling off volatile substances such as essential oils from resin oils obtained from Pinaceae plants. For example, gum rosin, tall rosin, wood rosin A natural rosin such as: a polymerized rosin derived from the natural rosin; a stabilized rosin obtained by disproportionating or hydrogenating the natural rosin or polymerized rosin; a maleic acid-modified rosin, a maleic anhydride rosin, a fumaric acid-modified rosin , Itaconic acid-modified rosin, Crotonic acid-modified rosin, Cinnamic acid-modified rosin, Acrylic acid-modified rosin, Unsaturated acid-modified rosin such as Methacrylic acid-modified rosin, etc. These are used alone or in combination of two or more. can do. Of these, natural rosin, particularly gum rosin or tall rosin is preferred.

Fatty acid (c) :
The fatty acid (c) includes aliphatic monocarboxylic acids having 6 to 24 carbon atoms, particularly 12 to 20 carbon atoms, and unsaturated fatty acids and saturated fatty acids known per se can be used without particular limitation. For example, fish oil Fatty acids, dehydrated castor oil fatty acids, safflower oil fatty acids, linseed oil fatty acids, soybean oil fatty acids, sesame oil fatty acids, poppy oil fatty acids, eno oil fatty acids, hemp oil fatty acids, grape kernel oil fatty acids,
Dry oil fatty acids such as corn oil fatty acid, tall oil fatty acid, sunflower oil fatty acid, cottonseed oil fatty acid, walnut oil fatty acid, rubber oil of seed oil; non-drying oil fatty acid such as coconut oil fatty acid, hydrogenated coconut oil fatty acid, palm oil fatty acid; Examples thereof include saturated fatty acids such as acid, capric acid, lauric acid, myristic acid, palmitic acid and stearic acid. In the present invention, it is suitable to use a dry oil fatty acid as the fatty acid (c) from the viewpoints of initial drying property and room temperature curability of the formed coating film.

Polyisocyanate compound (d) :
The polyisocyanate compound (d) is a compound having at least two isocyanates in one molecule. For example, tolylene diisocyanate (usually called “TDI”), xylylene diisocyanate, phenylene diisocyanate, diphenylmethane-2,4 ′. -Diisocyanate, diphenylmethane-4,4'-diisocyanate (usually called "MDI"), crude MDI, bis (isocyanatomethyl) cyclohexane, tetramethylene diisocyanate, hexamethylene diisocyanate, methylene diisocyanate, isophorone diisocyanate (usually called "IPDI") ) Aromatic, aliphatic or alicyclic polyisocyanate compounds; cyclized polymers of these polyisocyanate compounds, isocyanate biuret bodies; Ethylene glycol excess et polyisocyanate compounds, propylene glycol, may be mentioned trimethylolpropane, hexanetriol, castor oil terminal isocyanate-containing compounds obtained by reacting a low molecular weight active hydrogen-containing compounds such like. These can be used alone or in combination of two or more. Of these, TDI, MDI, IPDI and the like are preferable.

  In the present invention, the modified epoxy resin (I) can be produced by reacting the above-described epoxy resin (a), rosin (b), fatty acid (c) and polyisocyanate compound (d).

  Specifically, for example, first, the epoxy resin (a), the rosins (b) and the fatty acid (c) are heated to a temperature of about 80 to about 200 ° C., preferably about 100 to about 160 ° C. To obtain a reaction product having a hydroxyl group. At this time, a quaternary ammonium salt catalyst such as tetraethylammonium bromide or an amine catalyst can be used as necessary.

  In the above reaction, the proportions of the epoxy resin (a), the rosins (b) and the fatty acid (c) can be freely selected as long as the epoxy group remains in the reaction product. The carboxyl group of the rosins (b) is generally 0.03 to 0.40 equivalent, preferably 0.04 to 0.35 equivalent, more preferably 0 to 1 equivalent of the epoxy group of the epoxy resin (a). Within the range of 0.05 to 0.30 equivalent, and the carboxyl group of the fatty acid (c) is generally 0.15 to 0.55 equivalent, preferably 0.20 to 0.50 equivalent, more preferably 0.20 to 0. It is preferable that the ratio be in the range of .45 equivalents.

  Epoxy resin (a) and rosins in such a ratio that the equivalent of the carboxyl group of rosin (b) and the equivalent of the carboxyl group of fatty acid (c) are within the above range with respect to 1 equivalent of epoxy group of epoxy resin (a). By reacting (b) and the fatty acid (c), it is possible to obtain a modified epoxy resin having both initial drying properties and solubility in a weak solvent and having a wide choice of solvent.

Next, the polyisocyanate compound (d) is reacted with the hydroxyl group of the reaction product thus obtained at a temperature of about 50 to about 150 ° C., particularly about 70 to about 120 ° C. until the isocyanate group of the reaction mixture disappears. Let Thus, the modified epoxy resin (I) having an epoxy group can be obtained. At this time, an organic tin catalyst such as dibutyltin dilaurate can be used as necessary.

  The polyisocyanate compound (d) is used in an amount equivalent to 1 equivalent of hydroxyl group in the reaction product of epoxy resin (a), rosin (b) and fatty acid (c) from the viewpoint of coating film performance and solubility in weak solvents. In contrast, the isocyanate group equivalent in the polyisocyanate compound (d) is usually in the range of 0.10 to 1.10 equivalent, particularly 0.30 to 1.10 equivalent, more particularly 0.50 to 1.10 equivalent. A suitable amount is suitable.

  The modified epoxy resins thus obtained are those having an epoxy group in the molecule, generally 450-1500, especially 500-1300, more particularly 600-1200, and generally 600-3000, especially 800-2000. In particular, it may have a number average molecular weight in the range of 1000-1500.

  In the present invention, since the modified epoxy resin (I) can be diluted with a weak solvent, the weak solvent can be used as a reaction solvent at the time of resin production or a dilution solvent in a coating composition. Depending on the case, other organic solvents other than the weak solvent may be used as the reaction solvent or the diluting solvent.

Amine curing agent (II) :
As the amine curing agent (II), any known curing agent for epoxy resins having an active hydrogen group that reacts with an epoxy group can be used. For example, metaxylenediamine, isophoronediamine, diethylenetriamine, triethylene Polyamines such as tetramine and diaminodiphenylmethane; epoxy resin adducts and ketimines of the polyamines; polyamidoamines and polyamide resins. These can be used alone or in combination of two or more.

  The use ratio of the modified epoxy resin (I) and the amine curing agent (II) is such that the active hydrogen group of the amine curing agent (II) is usually 0.5 per 1 equivalent of the epoxy group contained in the modified epoxy resin (I). It is desirable that the ratio be in the range of -1.5 equivalents, particularly 0.6-1.2 equivalents, more particularly 0.8-1.1 equivalents.

Coating composition and coating method thereof :
Since the epoxy resin composition of the present invention comprising the modified epoxy resin (I) and the amine curing agent (II) described above can be easily diluted with a weak solvent such as mineral spirit, the degree of freedom in selecting a solvent. And is useful as a coating film forming component for paints.

  Therefore, according to this invention, the coating composition containing this epoxy resin composition is provided.

  The coating composition of the present invention is a two-component paint containing a main component containing a modified epoxy resin (I) and an amine curing agent (II) as a curing agent, depending on the type of amine curing agent (II) used, or It can be prepared in the form of a paint such as a one-component paint containing both.

  In the coating composition of the present invention, if necessary, pigments such as color pigments, extender pigments, rust preventive pigments; resin components such as modified resins; thickeners, dispersants, metal dryers, surface conditioners Additives for paints such as can be appropriately blended.

The coating composition of the present invention is excellent in coating workability, and the coating film to be formed has excellent initial drying properties and good finish, and can be applied as a base to various substrate surfaces. The substrate surface on which the coating composition is coated is not particularly limited, and includes, for example, a metal material surface such as iron, aluminum, and zinc and its surface-treated surface; concrete, mortar, slate, wood, plastic, stone, etc. Examples thereof include a material surface and a surface-treated surface thereof; and an old coating surface provided on the material surface and the surface-treated surface.

  The coating can be performed by a general method, for example, brush coating, spray coating, roller coating, trowel coating, various coater coating, and the like. Accordingly, an intermediate coating and / or a top coating can be applied. The intermediate coating and top coating are not particularly limited, and known organic solvent-type or water-based coatings can be used. For example, epoxy resin-based, acrylic resin-based, urethane resin-based acrylic rubber-based, silicon resin And fluororesin-based paints.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to only these examples. In the following examples, “part” and “%” mean “part by mass” and “% by mass”, respectively.

Production of rosin-modified epoxy resin solution Production Example 1
In a reactor having a heating device, a stirrer, and a nitrogen introduction tube, 185 parts of “JER828” (trade name, manufactured by Japan Epoxy Resin, bisphenol A type epoxy resin having an epoxy equivalent of 185), 51 parts of gum rosin and 98 parts of soybean oil fatty acid Was heated to 160 ° C. with stirring under a dry nitrogen atmosphere and reacted until the acid value became zero. After charging 160 parts of “Swazole 1000” (trade name, manufactured by Cosmo Oil Co., Ltd., boiling point 162-176 ° C.), 38 parts of diphenylmethane-4,4′-diisocyanate was added and reacted at 100 ° C. until the isocyanate group disappeared. Thus, a rosin-modified epoxy resin solution (I) having an epoxy equivalent of 745 and a heating residue of 70% was obtained.

Production Example 2
In a reaction apparatus having a heating apparatus, a stirrer and a nitrogen introduction tube, 250 parts of “JER834” (trade name, manufactured by Japan Epoxy Resin, bisphenol A type epoxy resin having an epoxy equivalent of 250), 17 parts of tall rosin and 56 dehydrated castor oil fatty acid 56 Was heated to 160 ° C. with stirring under a dry nitrogen atmosphere and reacted until the acid value reached zero. “Swasol 1000” 145 parts charged After cooling, 18 parts of tolylene diisocyanate were charged and reacted at 100 ° C. until the isocyanate group disappeared to obtain a rosin-modified epoxy resin solution (II) having an epoxy equivalent of 455 and a heating residue of 70%. It was.

Production Example 3
185 parts of “JER828”, 68 parts of tall rosin and 126 parts of soybean oil fatty acid were charged into a reactor having a heating device, a stirrer and a nitrogen introduction tube, and heated to 160 ° C. with stirring in a dry nitrogen atmosphere. The reaction was continued until 0 was reached. 170 parts of “Swazole 1000” is charged, and after cooling, 21 parts of diphenylmethane-4,4′-diisocyanate is added and reacted at 100 ° C. until the isocyanate group disappears. The rosin-modified epoxy resin solution has an epoxy equivalent of 1200 and a heating residue of 70%. (III) was obtained.

Production Example 4
In a reactor having a heating device, a stirrer and a nitrogen introduction tube, 165 parts of “JER806” (trade name, manufactured by Japan Epoxy Resin, bisphenol F type epoxy resin having an epoxy equivalent of 165), 102 parts of wood rosin and 56 parts of linseed oil fatty acid Was heated to 160 ° C. with stirring under a dry nitrogen atmosphere and reacted until the acid value became zero. After charging 160 parts of “Swazole 1000” and cooling, 55 parts of isophorone diisocyanate was added and reacted at 100 ° C. until the isocyanate group disappeared to obtain a rosin-modified epoxy resin solution (IV) having an epoxy equivalent of 760 and a heating residue of 70%. It was.

Production Example 5
185 parts of “JER828”, 68 parts of gum rosin and 84 parts of linseed oil fatty acid were charged into a reactor having a heating device, a stirrer and a nitrogen introduction tube, and heated to 160 ° C. with stirring in a dry nitrogen atmosphere. The reaction was continued until zero. “Swasol 1000” 150 parts charged After cooling, 9 parts of tolylene diisocyanate were charged and reacted at 100 ° C. until the isocyanate group disappeared. A rosin-modified epoxy resin solution having an epoxy equivalent of 690 and a heating residue of 70% was obtained as (V). Obtained.

Production Example 6
185 parts of “JER828”, 68 parts of tall rosin and 140 parts of soybean oil fatty acid are charged into a reactor having a heating device, a stirrer and a nitrogen introduction tube, and heated to 160 ° C. with stirring in a dry nitrogen atmosphere. The reaction was continued until zero. "Swasol 1000" 180 parts charged After cooling, 30 parts of tolylene diisocyanate were charged and reacted at 100 ° C until the isocyanate group disappeared, and a rosin-modified epoxy resin solution having an epoxy equivalent of 1410 and a heating residue of 70% was obtained as (VI). Obtained.

Production of modified epoxy resin solution without rosin modification Production Example 7
185 parts of “JER828” and 140 parts of dehydrated castor oil fatty acid are charged into a reactor having a heating device, a stirrer and a nitrogen introduction tube, and heated to 160 ° C. with stirring in a dry nitrogen atmosphere until the acid value becomes zero. Reacted. “Swazole 1000” 160 parts charged After cooling, 44 parts of tolylene diisocyanate were charged and reacted at 100 ° C. until the isocyanate group disappeared to obtain a modified epoxy resin solution (VII) having an epoxy equivalent of 735 and a heating residue of 70%. .

Production of modified epoxy resin solution without isocyanate modification Production Example 8
185 parts of “JER828”, 68 parts of gum rosin and 84 parts of linseed oil fatty acid were charged into a reactor having a heating device, a stirrer and a nitrogen introduction tube, and heated to 160 ° C. with stirring in a dry nitrogen atmosphere. The reaction was continued until zero. A modified epoxy resin solution (VIII) which was charged with 145 parts of “Swazole 1000”, epoxy equivalent 675, and 70% of the heating residue was not subjected to isocyanate modification.

Production of modified resin solution having no epoxy group Production Example 9
185 parts of “JER828”, 102 parts of gum rosin and 196 parts of soybean oil fatty acid were charged into a reactor having a heating device, a stirrer and a nitrogen introduction tube, and heated to 160 ° C. with stirring in a dry nitrogen atmosphere. The reaction was continued until zero. "Swasol 1000" 230 parts charged After cooling, 60 parts of tolylene diisocyanate was charged and reacted at 100 ° C until the isocyanate groups disappeared, and a modified resin solution (IX) having no epoxy groups and having a heating residue of 70% was obtained. Obtained.

  In the said manufacture examples 1-9, each equivalent ratio of the carboxyl group contained in the rosins and fatty acid with respect to 1 equivalent of epoxy groups contained in an epoxy resin, the epoxy equivalent of a modified resin, the isocyanate group with respect to 1 equivalent of hydroxyl groups in a reaction product The equivalent ratio is shown in Table 1 below.

Production of coating composition Examples 1-6 and Comparative Examples 1-4
A pigment, an additive, and the like were mixed with each modified resin solution obtained in the above production example in the composition shown in Table 2, and subjected to a dispersion treatment to prepare a coating base agent. A curing agent and a solvent shown in Table 2 were added thereto, mixed and stirred to prepare each coating composition, and subjected to the following performance test. The results are also shown in Table 2.

（注１）「酸化鉄ＫＰ−１０５」： 新日本金属化学工業（株）製、酸化鉄主体（有効成
分９７％）赤錆色着色顔料、
（注２）「重質タンカルＡ」： 竹原化学工業（株）製、炭酸カルシウム、
（注３）「Ｓ タルク」： 日本滑石精練（株）、酸化マグネシウム、アルミナ主成分の
体質顔料、
（注４）「ディスパロン６９００−１０Ｘ」： 楠本化成（株）製、アマイドワックス系
タレ止め剤、
（注５）「ＢＹＫ−０６６」： ビックケミージャパン（株）製、消泡剤、
（注６）「バーサミンＫ−１３」： コグニスジャパン（株）製、ケチミン化合物、活性
水素当量９１。

(Note 1) “Iron oxide KP-105”: manufactured by Shin Nippon Metal Chemical Co., Ltd.
97%) Red rust colored pigment,
(Note 2) “Heavy Tankar A”: Takehara Chemical Industry Co., Ltd., calcium carbonate,
(Note 3) “S talc”: Nippon Taishi Smelting Co., Ltd.
Extender pigments,
(Note 4) “Disparon 6900-10X”: Amido wax, manufactured by Enomoto Kasei Co., Ltd.
Sagging agent,
(Note 5) “BYK-066”: manufactured by Big Chemie Japan Co., Ltd., antifoaming agent,
(Note 6) “Versamine K-13”: manufactured by Cognis Japan, ketimine compound, activity
Hydrogen equivalent 91.

Evaluation test method (* 1) Weak solvent solubility:
"HAWS" (trade name, manufactured by Shell Chemicals Japan, petroleum hydrocarbon solvent) is added to each modified resin solution (I) to (IX) used in each coating composition in a 5 ° C environment. The solubility was confirmed visually.

  If the amount of “HAWS” added at the time of turbidity is> 300% with respect to the mass of each modified resin solid, “◯”, if it is 100-300%, “Δ”, if <100%, X ”.

(* 2) Finishability:
Each coating composition was applied onto a glass plate with a doctor blade having a gap of 6 mil, and the coating film obtained after 16 hours in a 23 ° C. environment was visually evaluated according to the following criteria.
A: Very good,
○: Good,
Δ: Somewhat bad,
X: Defect.

(* 3) Initial drying property:
Each paint composition was coated on a tin plate so that the dry film thickness was 60 μm, dried at room temperature (20-24 ° C. environment) for 4 hours, and then the dryness to touch of the coating film surface was evaluated according to the following criteria. did.
A: No tack,
○: Very slight fingerprint remains
Δ: Tack remains,
X: Paint is applied to the finger.

Claims (10)

(I) Modification having an epoxy group obtained by reacting an epoxy resin (a) having at least two epoxy groups in one molecule, a rosin (b), a fatty acid (c) and a polyisocyanate compound (d) An epoxy resin composition comprising an epoxy resin and (II) an amine curing agent.   The epoxy resin composition according to claim 1, wherein the epoxy resin (a) has an epoxy equivalent of 300 or less.   The epoxy resin composition according to claim 1 or 2, wherein the rosin (b) is gum rosin or tall rosin.   The epoxy resin composition according to any one of claims 1 to 3, wherein the fatty acid (c) is a dry oil fatty acid.   In the epoxy resin (a), the rosin (b) and the fatty acid (c), the carboxyl group of the rosin (b) is 0.03 to 0.40 with respect to 1 equivalent of the epoxy group contained in the epoxy resin (a). The epoxy resin composition according to any one of claims 1 to 4, wherein the epoxy resin composition is used at a ratio such that the carboxyl group of the fatty acid (c) is within a range of 0.15 to 0.55 equivalent within a range of equivalents. .   Isocyanate group equivalent in polyisocyanate compound (d) with respect to 1 equivalent of hydroxyl group in the reaction product obtained from polyisocyanate compound (d) from epoxy resin (a), rosin (b) and fatty acid (c) The epoxy resin composition according to any one of claims 1 to 5, wherein the epoxy resin composition is used at a ratio such that the amount is in the range of 0.10 to 1.10 equivalent.   The epoxy resin composition according to any one of claims 1 to 6, wherein the modified epoxy resin (I) has an epoxy equivalent weight within a range of 450 to 1500.   In the modified epoxy resin (I) and the amine curing agent (II), the active hydrogen group of the amine curing agent (II) is 0.5 to 1.5 equivalents with respect to 1 equivalent of the epoxy group contained in the modified epoxy resin (I). The epoxy resin composition according to any one of claims 1 to 7, which is contained in such a ratio that it falls within the range of.   The coating composition containing the epoxy resin composition of any one of Claims 1-8.   A coating method comprising coating the coating composition according to claim 9 on a substrate surface.