JPH09143241A - Epoxy resin and resin composition for coating - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a bisphenol type epoxy resin lowered in a resin solution viscosity which is a problem on production processes and on practical employment, simultaneously giving coating films having excellent mechanical characteristics, when used for coatings, and suitably used as a coating resin. SOLUTION: This bisphenol type epoxy resin has a skeleton wherein >=20% of the repeating units in the resin skeleton are originated from 1,1-bis(4- hydroxyphenyl)ethane and/or its glycldylether compound and <=80% of the repeating units in the resin skeleton are originated from at least one kind of compound selected from a compound having two aromatic hydroxyl groups in the molecule, except the 1,1-bis(4-hydroxyphenyl)ethane, and its glycidylether compound, and has a number-average mol.wt. of 8000-20000. This resin composition for the coatings contains the epoxy resin in an amount of >=30wt.% in the resin solid content.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a novel bisphenol type epoxy resin which is preferably used as a constituent resin component of coating materials such as paints and films, and a coating resin composition containing the same.

[0002]

2. Description of the Related Art Generally, an epoxy resin may refer to a liquid epoxy resin which is a bisphenol A diglycidyl ether compound based on a reaction between 2,2-bis (4-hydroxyphenyl) propane (bisphenol A) and epichlorohydrin. In many cases, since this liquid epoxy resin has a plurality of highly reactive glycidyl groups in the molecule, it is often used as a curability-imparting component in combination with an appropriate curing agent in various paints, adhesives and the like.

Further, also in paints for metals, an epoxy resin is often used as a constituent resin component thereof. In metal coatings, the coating is often required to have workability, and when the coating has an excessively cross-linked structure, the workability and the adhesion of the work are often lost. On the other hand, when the crosslink density is excessively low, the cured film will have poor solvent resistance and the like. As a method to solve such conflicting problems,
Attempts have also been made to improve the film properties by appropriately suppressing the curability of the epoxy resin. That is, the molecular weight of the bisphenol A diglycidyl ether type epoxy resin is increased to improve the flexibility of the epoxy resin itself, and at the same time, the density of the glycidyl groups present in the molecule of the epoxy resin is decreased to improve the processability by lowering the crosslink density. It is intended to try. Still another object of the invention is to add a reactive substance to a part of the glycidyl group present at the terminal of the epoxy resin having a relatively high molecular weight to lower the crosslinking density of the coating and improve the coating properties.

Among these, the bisphenol A diglycidyl ether type epoxy resin has a particularly high molecular weight and is therefore equivalent to the epoxy equivalent for applications in which high processability, substrate adhesion, solvent resistance, etc. are required. In many cases, those having a high value are preferably used. However, when a high molecular weight epoxy resin is used, the physical properties of the coating, such as processability, are greatly improved, but the viscosity of the resin increases, which hinders the manufacturing process and is actually used in solvent-based paints. In such a case, the viscosity of the paint or the like becomes high, and it is often necessary to use it as a solution having a low resin content by diluting it with an organic solvent or the like.

The bisphenol type epoxy resin used as the epoxy resin for paint is generally a bisphenol A diglycidyl ether type epoxy resin which is an adduct of bisphenol A and epihalohydrin. For this reason, studies have been added to contribute to lowering the viscosity. That is, instead of bisphenol A, there is a proposal for lowering the viscosity of a resin solution by using a bisphenol F type epoxy resin.
No. publication. According to the invention, it is possible to significantly reduce the solution viscosity of the epoxy resin by using a high molecular weight bisphenol F type epoxy resin obtained from bisphenol F having a binuclear purity of a certain level or higher as a raw material. Due to its synthesis process, bisphenol F is a by-product of not a few so-called polynuclear components having three or more phenolic hydroxyl groups in the molecule. The presence of this polynuclear component forms a branched structure during the synthesis of the high molecular weight epoxy resin, and when this is remarkable, it leads to gelation based on the development of a large-scale three-dimensional crosslinked structure. The invention suppresses the content of the polynuclear component that causes the crosslinked structure to a certain content or less, and suppresses an increase in viscosity of the resin solution due to crosslinking,
It realizes a low solution viscosity based on the flexibility of the bisphenol F skeleton.

However, according to the study by the present inventors, the high molecular weight epoxy resin thus obtained is
Although it is possible to achieve the desired reduction in solution viscosity to some extent, the coating properties when used in paints etc. are bisphenol A.
It is significantly reduced as compared with the case of using the high molecular weight epoxy resin. That is, a cured product in which the high workability of the high molecular weight epoxy resin is remarkably impaired is provided. The reason for this has not been fully clarified, but since the raw materials used when synthesizing the bisphenol F-type high molecular weight epoxy resin have a limited amount of polynuclear bodies of three or more nuclear bodies, It is presumed that the resin obtained has a branched structure, and as a result, the mechanical properties of the coating are significantly deteriorated.

[0007]

SUMMARY OF THE INVENTION The present invention solves the above problems and suppresses the viscosity of a resin solution, which is a problem in the manufacturing process or in practical use, at the same time, and is an excellent machine when used in a paint or the like. An object of the present invention is to provide a bisphenol type epoxy resin which gives a film having characteristics and is suitably used as a resin for coating.

[0008]

That is, according to the present invention, 20% or more of the repeating units in the resin skeleton are 1,1-bis (4
-Hydroxyphenyl) ethane and / or its skeleton derived from a glycidyl ether compound, and 80% or less of the repeating units in the resin skeleton have two aromas in the molecule other than 1,1-bis (4-hydroxyphenyl) ethane. A skeleton derived from at least one compound selected from a compound having a group hydroxyl group and its glycidyl ether compound,
A bisphenol-type epoxy resin having a number average molecular weight of 8,000 to 20,000.

In the present invention, 20% or more of the repeating units in the resin skeleton are derived from 1,1-bis (4-hydroxyphenyl) ethane and / or its glycidyl ether compound, and the repeating units in the resin skeleton are 80% of unit
The following is bis (hydroxyphenyl) methane, 2,2-
A skeleton derived from at least one compound selected from bis (4-hydroxyphenyl) propane, 2,2-bis (4-hydroxyphenyl) butane, bis (4-hydroxyphenyl) ether and glycidyl ether compounds thereof, A bisphenol-type epoxy resin having a number average molecular weight of 8,000 to 20,000. The present invention further provides a coating resin composition containing the epoxy resin in an amount of 30% by weight or more in the resin solid content.

The 1,1-bis (4-hydroxyphenyl) ethane that characterizes the resin of the present invention is conventionally referred to as bisphenol E, which is hereinafter conveniently referred to as bisphenol E. Due to the synthetic process, bisphenol E industrially supplied has a very small amount of by-products of trinuclear or higher polynuclears. Therefore, bisphenol E is
It is presumed that a high molecular weight epoxy resin obtained by using it as a constituent does not form a branched structure, but a high molecular weight epoxy resin having a high linearity is obtained, and therefore a coating having good mechanical properties is provided. In addition, since the high molecular weight epoxy resin having a repeating unit derived from bisphenol E in the molecule has a lower symmetry of the molecular structure of its skeleton than the bisphenol A type epoxy resin, the intramolecular or intermolecular interaction is low. It is considered that formation of higher-order structures is reduced, and this is considered to contribute to lowering the viscosity of the resin solution.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The bisphenol type epoxy resin and the coating resin composition of the present invention will be described in detail below. In the present invention, “%” represents “mol%” unless otherwise specified. The bisphenol type epoxy resin of the present invention is characterized in that 20% or more of the repeating units in the resin skeleton are skeletons derived from bisphenol E and / or its glycidyl ether compound. When the content of the skeleton derived from bisphenol E and / or its glycidyl ether compound is less than 20%, it is difficult to realize the effect of lowering the viscosity brought by the introduction of the bisphenol E structure, and it is possible to achieve the object of the present invention. Have difficulty.

Also, bisphenol E occupying 80% or less of the repeating units in the resin skeleton of the epoxy resin of the present invention.
There is no particular limitation on the compound having two aromatic hydroxyl groups in the molecule other than the above and its glycidyl ether compound, but bisphenol F (bis (hydroxyphenyl) methane), bisphenol A (2,2-bis (4-hydroxy) (Phenyl) propane), bisphenol B (2,2
-Bis (4-hydroxyphenyl) butane), bisphenol S (bis (4-hydroxyphenyl) sulfone)
, 2,2-bis (4-hydroxyphenyl) -4-methylpentane, 1,1-bis (4-hydroxyphenyl) -2-methylpropane, bis (4-hydroxyphenyl) phenylmethane, bis (4-hydroxy) -3,5
-Dimethylphenyl) methane, 1,1-bis (4-hydroxy-3,5-dimethylphenyl) ethane, 2,2-
Bis (4-hydroxy-3,5-dimethylphenyl) propane, 2,2-bis (4-hydroxy-3,5-dimethylphenyl) butane, 2,2-bis (4-hydroxy-3-methylphenyl) butane Examples include 1,1-bis (4-hydroxy-3-methylphenyl) -2-phenylethane, biphenol, bis (4-hydroxyphenyl) ether, bis (4-hydroxyphenyl) ketone, and glycidyl ether compounds thereof. As.

Among them, bis (hydroxyphenyl) methane, 2,2-bis (4-hydroxyphenyl) propane, 2,2-bis (4-hydroxyphenyl) butane,
Bis (4-hydroxyphenyl) ether and glycidyl ether compounds thereof are preferably used. These compounds can be used alone or in combination of two or more kinds. Among the bisphenols exemplified above, as described above, bisphenol F contains a polynuclear compound having three or more nuclei that causes a branched structure depending on the degree of purification thereof, so that the amount used may be small. More preferable.

The epoxy resin of the present invention is characterized by having a number average molecular weight in the range of 8000 to 20000. When the number average molecular weight is less than 8,000,
Although the resin viscosity is relatively low, it is often difficult to realize sufficient characteristics in mechanical properties of the coating film obtained when it is used for paints and the like. In addition, the number average molecular weight is 2
When it exceeds 0000, the coating film obtained when used in a paint or the like can realize very excellent mechanical properties, etc., but the resin viscosity becomes remarkably high, and sufficient uniformity cannot be secured during production. It is also not preferable because it is not easy to handle. The "number average molecular weight" used in the present invention means a polystyrene reduced molecular weight calculated by GPC (gel permeation chromatography) measurement.

The epoxy resin containing the bisphenol E skeleton of the present invention in its molecule has a very high molecular weight, unlike liquid epoxy resins which are generally used.
The thermosetting property, which is found in general liquid epoxy resins, becomes low and the thermoplasticity becomes strong. Further, the epoxy resin of the present invention is characterized by its main chain skeleton structure, and the glycidyl group usually present at the terminal of the epoxy resin does not exert a dominant effect in the present invention. Therefore, the terminal structure of the epoxy resin of the present invention is such that the resin viscosity is remarkably increased, or when it is used in a paint or the like, the film properties are remarkably deteriorated,
There is no particular limitation as long as it does not hinder the compounding in a paint or the like. For example, in addition to the glycidyl group and the phenolic hydroxyl group, a structure in which the glycidyl group is modified with various carboxylic acids, amines, thiols, alcohols, phenols and the like or a glycol structure may be used.

The epoxy resin of the present invention can be manufactured by a method similar to the method for manufacturing a bisphenol A type epoxy resin. That is, a toffee method by addition of epihalohydrin and bisphenols using sodium hydroxide, potassium hydroxide, etc. as a catalyst, or a low molecular weight liquid epoxy resin which is a bisphenol glycidyl ether compound by addition of epihalohydrin and bisphenols is further added by bisphenols. It can be produced by the advanced method by chain extension. The epoxy resin of the present invention can be produced by either of the above two production methods, but it is possible to limit the use of highly toxic epihalohydrin in the production process,
In many cases, the advanced method is more rational because it requires simple manufacturing equipment. Therefore, the process for producing the epoxy resin of the present invention by the advanced method will be described below.

The epoxy resin of the present invention has 2 in its molecule.
Although it has 0% or more of bisphenol E skeleton, the bisphenol E skeleton may be derived from either bisphenol E or bisphenol E glycidyl ether compound which is a raw material in the advanced method. The bisphenol E type low molecular weight liquid epoxy resin containing bisphenol E glycidyl ether compound as a main component can be obtained by the same method as a usual method used for obtaining a bisphenol A type liquid epoxy resin. Generally, bisphenol E is dissolved in a large excess of epichlorohydrin, the addition reaction is allowed to proceed using a catalyst such as sodium hydroxide or potassium hydroxide, and then the product is obtained through a purification step such as removal of by-products. You can Also,
The bisphenol skeleton other than the bisphenol E skeleton constituting the epoxy resin of the present invention may also be derived from either the bisphenol itself or the glycidyl ether compound of the bisphenol.

The epoxy resin of the present invention can be obtained by an addition reaction of the above-mentioned bisphenol E glycidyl ether compound or glycidyl ether compound of other bisphenols and bisphenol E or other bisphenols. These components are reacted at a compounding ratio based on the epoxy equivalent of the bisphenol E glycidyl ether compound or the glycidyl ether compound of other bisphenols and the hydroxyl equivalent of bisphenol E or the other bisphenols. Here, the epoxy equivalent means the average molecular weight per 1 mol of the epoxy group, and similarly, the hydroxyl group equivalent means the average molecular weight per 1 mol of the hydroxyl group. Usually, epoxy groups in glycidyl ethers of bisphenols 1
It is preferable to set the compounding ratio so that the number of phenolic hydroxyl groups derived from bisphenols is 0.90 to 1.10. It should be noted that if the amount is out of this range, it often becomes difficult to achieve the high molecular weight required for the epoxy resin of the present invention.

The addition reaction can be carried out without a solvent or in an organic solvent. The organic solvent does not inhibit the originally expected addition reaction of the phenolic hydroxyl group to the glycidyl group, and dissolves the glycidyl ether compound of bisphenols and bisphenols and the high molecular weight epoxy resin produced by these additions or Can be used without particular limitation as long as it is dispersed.
Usually, a ketone solvent, an ester solvent, an aromatic hydrocarbon solvent, an alcohol solvent, an amide solvent and the like are preferably used. This addition reaction is generally preferably carried out in the temperature range of 50 ° C to 200 ° C.

A suitable catalyst can be used for the addition reaction. Usually, as a catalyst that is preferably used as a catalyst for promoting the addition reaction of an epoxy compound and a phenol, sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium carbonate, calcium carbonate, lithium chloride, triethylamine, tripropylamine, Tributylamine, dimethylethanolamine,
Methyldiethanolamine, dimethylaniline, dimethylbenzylamine, tetramethylammonium hydroxide, tetramethylammonium chloride, tetramethylammonium bromide, tetramethylammonium iodide, tetraethylammonium chloride, tetraethylammonium bromide, tetraethylammonium iodide, tetramethylamine tetrafluoride Examples thereof include boron fluoride complex, tripropylphosphine, tributylphosphine, triphenylphosphine and tetrabutylphosphonium chloride.

The epoxy resin of the present invention may be used as it is in a paint or the like by appropriately diluting it with an organic solvent or the like.
It can be formed into a film and used as various coating films. Further, the resin composition for coating obtained by blending other resin components, various additives, colorants and the like can be used as a paint or a film. At this time, in the resin solid content of the coating resin composition,
It is necessary that the epoxy resin of the present invention is contained in an amount of 30% by weight or more of the resin solid content. If the amount of the epoxy resin of the present invention in the resin solid content of the coating resin composition is less than 30% by weight, the excellent properties of the epoxy resin may not be exhibited in many cases, which is not preferable.

There are no particular restrictions on the components to be added to the coating resin composition, and if necessary, for example, resin components such as alkyd resin, acrylic resin, urethane resin, polyester resin, melamine resin, phenol resin and the present invention can be used. Epoxy resins other than the above epoxy resins can be blended. These resins are merely examples, and the resins mixed in the coating resin composition of the present invention are not limited to these. If necessary, in addition to colorants such as dyes and pigments, various additives such as fillers,
Leveling agent, curing agent, flame retardant, thickener, antioxidant,
An ultraviolet absorber, a plasticizer, an antistatic agent, a lubricant, a defoaming agent, an organic solvent, etc. can be added.

[0023]

EXAMPLES The present invention will be described below in more detail with reference to examples, but these examples do not limit the present invention in any way. In the following Examples and Comparative Examples, "part" means "part by weight" unless otherwise specified.

Example 1 A reaction container equipped with a stirrer and a condenser was charged with an epoxy equivalent of 165 and an average molecular weight of 33.
100 parts of bisphenol E type liquid epoxy resin of 0 and 65 parts of bisphenol E were charged, and the temperature was 100 ° C under a nitrogen stream.
After heating to dissolve and homogenize, 0.8 part of tetraethylammonium iodide was added, and the temperature was raised to 130 ° C. After the reaction was continued for 6 hours at this temperature while appropriately adding butyl cellosolve for adjusting the viscosity, butyl cellosolve was finally added so that the nonvolatile content was about 60% by weight to obtain an epoxy resin solution (a).

Example 2 A reaction vessel equipped with a stirrer and a condenser was charged with an epoxy equivalent of 190 and an average molecular weight of 38.
0 parts of bisphenol A type liquid epoxy resin (“Epicoat 828” manufactured by Yuka Shell Epoxy Co., Ltd.), 56 parts of bisphenol E and 30 parts of butyl acetate were charged.
After heating to 100 ° C. under a nitrogen stream to dissolve and homogenize, 0.8 part of tetraethylammonium iodide was added, and the temperature was raised to 130 ° C. After the reaction was continued for 6 hours at this temperature while appropriately adding butyl cellosolve for adjusting the viscosity, butyl cellosolve was finally added so that the nonvolatile content was about 60% by weight to obtain an epoxy resin solution (b).

[Embodiment 3] An epoxy equivalent of 190 and an average molecular weight of 3 were placed in a reaction vessel equipped with a stirrer and a condenser.
80 parts of 80 bisphenol A type liquid epoxy resin, bisphenol E having an epoxy equivalent of 165 and an average molecular weight of 330
Mold liquid epoxy resin 50 parts, Bisphenol A 35 parts,
After charging 55 parts of bisphenol B and 30 parts of butyl acetate and heating to 100 ° C. under nitrogen stream to dissolve and homogenize, 1.0 part of tetraethylammonium iodide was added and the temperature was raised to 130 ° C. After the reaction was continued for 6 hours at this temperature while appropriately adding butyl cellosolve for adjusting the viscosity, butyl cellosolve was finally added so that the nonvolatile content was about 60% by weight to obtain an epoxy resin solution (c).

Example 4 A reaction vessel equipped with a stirrer and a condenser was charged with an epoxy equivalent of 165 and an average molecular weight of 33.
0 parts of bisphenol E type liquid epoxy resin, 36 parts of bisphenol E, 15 parts of p, p-bisphenol F and 20 parts of butyl acetate were charged, and the temperature was 100 ° C under a nitrogen stream.
After heating to dissolve and homogenize, 0.7 part of tetraethylammonium iodide was added, and the temperature was raised to 130 ° C. After continuing the reaction at this temperature for 6 hours while appropriately adding butyl cellosolve for adjusting the viscosity, butyl cellosolve was finally added so that the nonvolatile content was about 60% by weight to obtain an epoxy resin solution (d).

[Embodiment 5] A reaction vessel equipped with a stirrer and a condenser was charged with an epoxy equivalent of 165 and an average molecular weight of 33.
0 parts of bisphenol E type liquid epoxy resin, 61 parts of bis (4-hydroxyphenyl) ether and 20 parts of butyl acetate were charged and heated to 100 ° C. under nitrogen flow to dissolve and homogenize, and then tetraethylammonium iodide 0 0.8 part was added and the temperature was raised to 130 ° C.
The reaction was continued at this temperature for 6 hours while appropriately adding butyl cellosolve for adjusting the viscosity, and then butyl cellosolve was finally added so that the nonvolatile content was about 60% by weight to obtain an epoxy resin solution (e).

[Example 6] 80 parts of butyl acetate was charged into a reaction vessel equipped with a stirrer, a dropping tube and a condenser.
Heat to 80 ° C. under a stream of nitrogen. While maintaining the same temperature,
From a dropping tube, a mixture of 24 parts of styrene, 24 parts of 2-hydroxyethyl methacrylate, 24 parts of ethyl acrylate, 36 parts of methyl methacrylate, 12 parts of acrylic acid and 1.5 parts of benzoyl peroxide is dropped over about 2 hours. Then, after the dropping, the reaction is continued for another 4 hours, and the nonvolatile content is about 60% by weight.
Acrylic resin solution (A) was obtained. To 70 parts of the acrylic resin solution (A), 120 parts of the epoxy resin solution (a) obtained in Example 1, phenol resin (B) (nonvolatile content 50
% By weight, Hitachi Chemical Co., Ltd. “Hitanol 402
0 ") 12 parts and butyl cellosolve to give a nonvolatile content of 3
A coating resin composition (f) was obtained by diluting to 0% by weight.

[Example 7] Acrylic resin solution (A) 13
To 0 parts, 60 parts of an epoxy resin solution (a) and 12 parts of a phenol resin (B) are added, and a nonvolatile content of 3 is obtained with butyl cellosolve.
A coating resin composition (g) was obtained by diluting to 0% by weight.

[Comparative Example 1] A reaction vessel equipped with a stirrer and a condenser was charged with 60 parts of a bisphenol A type liquid epoxy resin having an epoxy equivalent of 190, 36 parts of bisphenol A and 20 parts of butyl acetate, and the mixture was heated to 100 ° C under a nitrogen stream.
After heating to dissolve and homogenize, 0.5 part of tetraethylammonium iodide was added, and the temperature was raised to 130 ° C. After continuing the reaction at this temperature for 6 hours while appropriately adding butyl cellosolve to adjust the viscosity, butyl cellosolve is finally added so that the nonvolatile content is about 60% by weight, and the epoxy resin solution containing the nonvolatile content is about 60% by weight. (H) was obtained.

[Comparative Example 2] An epoxy equivalent of 160 and an average molecular weight of 32 were placed in a reaction vessel equipped with a stirrer and a condenser.
80 parts of bisphenol F type liquid epoxy resin of 0, 50 parts of bisphenol F and 20 parts of butyl acetate were charged, heated to 100 ° C. under a nitrogen stream to dissolve and homogenize, and 0.7 part of tetraethylammonium iodide was added,
The temperature was raised to 130 ° C. After continuing the reaction at this temperature for 6 hours while appropriately adding butyl cellosolve for adjusting the viscosity, butyl cellosolve was finally added so that the nonvolatile content was about 60% by weight to obtain an epoxy resin solution (i).

Comparative Example 3 A reaction vessel equipped with a stirrer and a condenser was charged with an epoxy equivalent of 190 and an average molecular weight of 38.
0 parts of bisphenol A type liquid epoxy resin, 38 parts of bisphenol A, 9 parts of bisphenol E and 20 parts of butyl acetate were charged and heated to 100 ° C. under nitrogen stream to dissolve and homogenize, and then 0.6 parts of tetraethylammonium iodide. Was added and the temperature was raised to 130 ° C. After continuing the reaction at this temperature for 6 hours while appropriately adding butyl cellosolve for adjusting the viscosity, butyl cellosolve was finally added so that the nonvolatile content was about 60% by weight to obtain an epoxy resin solution (j).

Comparative Example 4 A reaction vessel equipped with a stirrer and a condenser was charged with an epoxy equivalent of 165 and an average molecular weight of 33.
100 parts of bisphenol E type liquid epoxy resin of 0 and 65 parts of bisphenol E were charged, and the temperature was 100 ° C under a nitrogen stream.
After heating to dissolve and homogenize, 0.8 part of tetraethylammonium iodide was added, and the temperature was raised to 130 ° C. After the reaction was continued for 2 hours at this temperature while appropriately adding butyl cellosolve for adjusting the viscosity, butyl cellosolve was finally added so that the nonvolatile content was about 60% by weight to obtain an epoxy resin solution (k).

Comparative Example 5 A reaction vessel equipped with a stirrer and a condenser was charged with an epoxy equivalent of 190 and an average molecular weight of 38.
0 bisphenol A type liquid epoxy resin 100 parts, bisphenol E 56 parts and butyl acetate 30 parts were charged,
After heating to 100 ° C. under nitrogen stream to dissolve and homogenize, 1.6 parts of tetraethylammonium iodide was added, and the temperature was raised to 180 ° C. The reaction was continued for 6 hours at this temperature while appropriately adding butyl cellosolve for adjusting the viscosity, and then butyl cellosolve was finally added so that the nonvolatile content was about 60% by weight to obtain an epoxy resin solution (l).

[Comparative Example 6] Acrylic resin solution (A) 17
20 parts of the epoxy resin solution (a) and 12 parts of the phenol resin (B) were added to 0 parts, and the nonvolatile content was 3 with butyl cellosolve.
The coating resin composition (m) was obtained by diluting to 0% by weight. [Comparative Example 7] 120 parts of an epoxy resin solution (h) and 12 parts of a phenol resin (B) were added to 70 parts of an acrylic resin solution (A), and the mixture was diluted with butyl cellosolve to a nonvolatile content of 30% by weight, and a coating resin. A composition (n) was obtained.

Properties of the epoxy resins contained in the epoxy resin solutions or coating resin compositions (a) to (n) obtained in Examples 1 to 7 and Comparative Examples 1 to 7 and the resin solutions or coating resins. Table 1 shows the characteristics of the coating films obtained from the compositions (a) to (n). In addition, each property and characteristic were measured by the methods described below. Solution viscosity: Resin solution or coating resin composition (a)-
Each of (n) was treated with butyl cellosolve to give a nonvolatile content of 30.
It diluted so that it might be set to weight%, and it measured at 25 degreeC with the Brookfield viscometer. Number average molecular weight: measured by GPC (in terms of polystyrene). Molecular weight distribution: The Mw / Mn ratio was determined from the weight average molecular weight (Mw) and number average molecular weight (Mn) obtained by GPC measurement.

Epoxy equivalent: In accordance with JIS K7236, TEAB
-Measured by the perchloric acid method. Workability: After coating the obtained resin solution or the coating resin compositions (a) to (n) on a release paper with a wire bar coater so that the dry film thickness becomes about 25 μm, 200
The resin film obtained by drying at 5 ° C. for 5 minutes was cut into a tape having a width of 20 mm, stretched at a chuck distance of 100 mm and a crosshead speed of 50 mm / min, and the elongation at break (%) was expressed. . Adhesion: Resin solution or coating resin composition (a) ~
(N) is dried with a wire bar coater to give a dry film thickness of about 15μ.
Apply it to the tin-free steel plate so that
It was dried at 0 ° C. for 5 minutes, and it was expressed by the ratio of the number of squares remaining without peeling in the cellophane tape peeling test for goggle.

[0039]

[Table 1]

[0040]

According to the present invention, it is possible to obtain a high molecular weight epoxy resin which is excellent in substrate adhesion, workability, etc., has a low solution viscosity and is easy to handle, and a coating resin composition containing the same. By using the high molecular weight epoxy resin and the coating resin composition of the present invention, it is possible to perform in a relatively high solid state the steps etc. that had to be conventionally improved by diluting with a large amount of an organic solvent to improve handleability. It is possible to reduce the amount of organic solvent used that causes air pollution and the like.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Takashi Ishikawa 2-3-13-1 Kyobashi, Chuo-ku, Tokyo Toyo Inki Manufacturing Co., Ltd.

Claims (3)

[Claims] 1. 20% or more of the repeating units in the resin skeleton are skeletons derived from 1,1-bis (4-hydroxyphenyl) ethane and / or its glycidyl ether compound, and 80% of the repeating units in the resin skeleton. The following is 1,1-
A skeleton derived from at least one compound selected from compounds having two aromatic hydroxyl groups in the molecule other than bis (4-hydroxyphenyl) ethane and glycidyl ether compounds thereof, and having a number average molecular weight of 8000 to 2000.
A bisphenol type epoxy resin characterized by being 0. 2. 20% or more of the repeating units in the resin skeleton are skeletons derived from 1,1-bis (4-hydroxyphenyl) ethane and / or its glycidyl ether compound, and 80% of the repeating units in the resin skeleton. The following are bis (hydroxyphenyl) methane, 2,2-bis (4-hydroxyphenyl) propane, 2,2-bis (4-hydroxyphenyl) butane, bis (4-hydroxyphenyl) ether and their glycidyl ether compounds. A bisphenol-type epoxy resin, which is a skeleton derived from at least one compound selected from the above, and has a number average molecular weight of 8,000 to 20,000. 3. A coating resin composition comprising the epoxy resin according to claim 1 or 2 in an amount of 30% by weight or more in a resin solid content.