JPH07207222A - Coating composition - Google Patents

Abstract

PURPOSE:To obtain a coating compsn. which gives a coating film excellent in corrosion resistance, adhesive properties, hygienic properties, flavor reservation, and processibility by dispersing or dissolving specified amts. of a phenoxy resin, an epoxy resin, and a phenol-formaldehyde resin in an org. solvent. CONSTITUTION:Coating compsn. is obtd. by dispersing or dissolving 15-100 pts.wt. phenoxy resin, 0-85 pts.wt. epoxy resin, and 1-50 pts.wt. resole-type phenol-formaldehyde resin, the sum of the phenoxy resin and the epoxy resin being 100 pts.wt.. The phenol-formaldehyde resin is prepd. by reacting a phenol with formaldehyde, comprises divalent repeating units of formula I or II [wherein R<1> is H, 1-20C alkyl, or a group of formula N (wherein R<2> is H or 1-6C alkyl; R<3> is Hor 1-3C alkyl; and z is 0-1)] provided that the number of repeating of the unit of formula 1 (x) is 0-6, that the number of repeating of the unit of formula II (y) is 2-14, and that x+y is 4-20, is virtually linear, has both molecular ends blocked with groups of formula IN, and has a mean value of z per molecule of 1.0-3.0.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a phenoxy / phenolic coating composition. More specifically, it is applied to a metal material directly or on a base coating composition, and has excellent flavor retention and processability, and also has corrosion resistance, adhesion, and The present invention relates to a coating composition particularly suitable for can inner surface coating capable of forming a coating film excellent in hygiene.

[0002]

2. Description of the Related Art Conventionally, as a can coating material for coating the inner surface of a can such as a can, at least one resin selected from the group consisting of a bisphenol A type epoxy resin, a resole type phenol resin and an amino resin. Mixtures with the components or their precondensates are generally widely used. However, cans coated with this paint have problems such as corrosion of the flange portion due to workability and corrosion of scratches caused by impact from the outside, and a coating film without the above problems can be formed. There has been a demand for a paint for the inner surface of a can.

As a means for solving these problems, as disclosed in JP-A-2-242865, a bisphenol type epoxy resin modified product and the bisphenol type epoxy resin modified product are treated with formaldehydes in the presence of a basic catalyst. A coating composition is disclosed which is a mixture with a resol-type phenol resin obtained by reacting with. However, the paint described in the publication is still insufficient in workability, and it is difficult to use the paint in applications requiring high workability such as easy-open lids, especially Stein tab lids. Met.

[0004]

DISCLOSURE OF THE INVENTION In view of the present situation, the present inventors have found that an inner surface of a can capable of forming a coating film excellent in flavor retention and processability, corrosion resistance, adhesion, hygiene and the like. As a result of earnest studies to develop a coating composition for use, it was found that the above object can be achieved by an organic solvent type coating containing a phenoxy resin and the following specific resol type phenol / formaldehyde resin as essential components, and the present invention is completed. Came to.

That is, according to the present invention: (A) 15-100 parts by weight of phenoxy resin and (B)
1 to 50 parts by weight of the following resole type phenol-formaldehyde resin obtained by reacting (C) phenols and aldehydes is dispersed in an organic solvent based on 100 parts by weight in total of 0 to 85 parts by weight of epoxy resin. Or, a coating composition characterized by being dissolved is provided.
The following general formula [1] or [2]

[0006]

[Chemical 5]

[0007]

[Chemical 6]

[Wherein R ¹ are the same or different and each represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms or the following general formula [3]

[0009]

[Chemical 7]

(In the formula, R ² is a hydrogen atom or a carbon atom number 1
To 6 alkyl groups, R ³ is the same or different, and a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and z is 0 or 1. ) Is a group represented by. ] The number of units x of the group of the formula [1] in one molecule is 0 to 6, and the number of units y of the group of the formula [2] is 2
14, and the sum of x and y is an integer of 4 to 20 and is substantially linear, and both ends of the molecule are each represented by the following general formula [4].

[0011]

[Chemical 8]

(Wherein R ¹ , R ² and z have the above-mentioned meanings), and the average sum of z per molecule is 1.0 to 3.0.
Resol type phenol-formaldehyde resin.

According to the present invention, 2. The compounding amount of the (A) phenoxy resin and the (B) epoxy resin is (A) 60.
The coating composition is characterized in that (B) is 0 to 40 parts by weight with respect to 100 parts by weight.

Further according to the present invention, 3. As the resin component, (D) a polyolefin having a static glass transition temperature of 0 ° C. or lower, which may be modified, is added to 5 to 30 parts with respect to 100 parts by weight of the total amount of the (A) component and the (B) component. The coating composition according to the above item 1 or 2, wherein the coating composition is contained by weight.

[0015]

In the present invention, the phenoxy resin as the component (A) is a mononuclear type or binuclear type divalent phenol or a mixed divalent phenol of mononuclear type and binuclear type in the presence of an alkali catalyst. It is a polymer obtained by polycondensation with an approximately equimolar amount of epihalohydrin. Examples of mononuclear dihydric phenols include resorcin, hydroquinone and catechol, and examples of binuclear phenols include bisphenol A and bisphenol F. These may be used alone or in combination of two or more. A representative example of epihalohydrin is epichlorohydrin. When the dihydric phenol is a mixture of resorcin and bisphenol A in a molar ratio of 1/1, the phenoxy resin is basically composed of a repeating unit represented by the following structural formula.

[0016]

[Chemical 9]

The repeating unit of the resin when the dihydric phenol is bisphenol A alone is represented by the following structural formula.

[0018]

[Chemical 10]

The phenoxy resin is a polyhydroxypolyether resin and is produced from the same raw material as the epoxy resin, but unlike the epoxy resin, does not have a terminal epoxy group and has a number average molecular weight of about 8,000 to 30, 000, which is a thermoplastic resin that is considerably larger than ordinary epoxy resins. A phenoxy resin produced from bisphenol A and epichlorohydrin is commercially available as phenoxy resin PKHH from Union Carbide Company, USA.

As is clear from the above structural formula, the phenoxy resin has a large number of OH groups and -O- groups in the chain.
Since the OH group forms a hydrogen bond with the substrate, it contributes to an increase in adhesion, and the -O- group easily causes intramolecular rotation, which contributes to an increase in flexibility of the resin. The phenoxy resin is advantageous in flexibility because it has no epoxy group and has a high molecular weight as compared with an epoxy resin.

In the present invention, the epoxy resin which is the component (B) preferably has a number average molecular weight of 400 to 6,000, for example, epichlorohydrin and polyphenol condensed to a high molecular weight in the presence of an alkali catalyst. , Those obtained by condensing epichlorohydrin and polyphenol into a low molecular weight epoxy resin in the presence of an alkali catalyst and subjecting this low molecular weight epoxy resin and bisphenol to a polyaddition reaction.

Examples of polyphenols used in the production of the above-mentioned epoxy resin include bis (4-hydroxyphenyl) -methane [bisphenol F], bis (4-hydroxyphenyl) -2,2-propane [bisphenol A], 4, 4'-dihydroxybenzophenone, bis (4-hydroxyphenyl) -1,1-ethane, bis-
(4-hydroxyphenyl) -1,1-isobutane, bis (4-hydroxy-tert-butyl-phenyl) -2,
2-propane, bis (2-hydroxynaphthyl) methane, 1,5-dihydroxynaphthalene, bis (2,4-)
Dihydroxyphenyl) methane, tetra (4-hydroxyphenyl) -1,1,2,2-ethane, 4,4'-dihydroxydiphenyl sulfone, phenol novolac, cresol novolac and the like can be mentioned. Of these, bisphenol A and bisphenol F are particularly suitable.

Specific examples of such epoxy resin include, for example, Epicoat 1004 (epoxy equivalent of about 900, number average molecular weight of about 1,400), Epicoat 1007 (epoxy equivalent of about 1,700, number average molecular weight of about 100, manufactured by Shell Chemical Co., Ltd.). 2,900), Epicoat 1009 (epoxy equivalent of about 3,500, number average molecular weight about 3,750), Epicoat 1010 (epoxy equivalent of about 4,500, number average molecular weight about 5,500) and the like.

In the present invention, the epoxy resin as the component (B) may be a resin partially reacted with a polyol, a polyether polyol, a polyester polyol, a polyamidoamine, a polycarboxylic acid, a polyisocyanate compound, etc. Further, it may be one obtained by graft-polymerizing ε-caprolactone, an acrylic monomer or the like. The above polycarboxylic acid has 3 to 1 carbon atoms.
The dicarboxylic acid of 4 is preferable, and specifically, succinic acid,
Adipic acid, pimelic acid, azelaic acid, sebacic acid,
Examples include dodecanedioic acid and hexahydrophthalic acid.

In the present invention, the resol type phenol-formaldehyde resin (hereinafter referred to as "phenol resin") used as the component (C) is obtained by reacting phenols with aldehydes, and one molecule of the above formula X (0 to 6) repeating units having a methylene bond represented by [1] and y (2 to 14) repeating units having a dimethylene ether bond represented by the above formula [2].
, And the sum of x and y is an integer of 4 to 20. x
If the sum of y and y is less than 4, the phenol resin is eluted in the sterilization process, which is not preferable in terms of hygiene. The sum of x and y is 20
If it exceeds, the viscosity will increase and the (A) component and (B)
The compatibility with the ingredients may deteriorate. Further, when the value of y is less than 2, the workability and the adhesion to the object to be coated are reduced, while
If it exceeds 4, the water resistance will decrease.

Further, the phenol resin in the present invention is
Alkyl etherification which is substantially linear and has both ends of the molecule blocked by the group represented by the above formula [4], and which is represented by (—CH ₂ OR ² ) _z per molecule. Sum of methylol groups and methylol groups (sum of z)
Average of 1.0 to 3.0, preferably 1.5 to 2.3
And z is 0 or 1. Z per molecule
When the average of the sum total of more than 3.0 is high, the crosslink density becomes high and the processability is deteriorated. On the other hand, when it is less than 1.0, the amount of phenol resin having no methylol group (alkyl etherification) increases and the resin hardens. It is no longer effective as an agent and the phenol resin is eluted during the sterilization process in can applications, which is unfavorable for hygiene.

In the above formulas [1] and [2], R ¹
Examples of the alkyl group having 1 to 20 carbon atoms include a methyl group, an ethyl group, a propyl group, a butyl group, a 2-ethylhexyl group, and a lauryl group. R ¹ is more preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. In the above formulas [3] and [4], R
Examples of the alkyl group having ² to 6 carbon atoms include a methyl group, an ethyl group, a butyl group and a hexyl group. In the above formula [3], the number of carbon atoms of R ³ is 1
Examples of the alkyl group of to 3 include a methyl group, an ethyl group and a propyl group.

The phenolic resin which is the component (C) in the present invention can be obtained by reacting phenols and formaldehydes with an organic acid metal salt as a catalyst under weak acidity. Preferred reaction conditions for reacting phenols and formaldehydes with an organic acid metal salt as a catalyst are that the compounding molar ratio of phenols and formaldehydes is 1.0 mol or more with respect to 1.0 mol of phenol nuclei. It is 0 mol or less, the reaction temperature is 80 to 140 ° C., the reaction time is 1 to 10 hours, and the resinification reaction is completed while removing water and unreacted raw materials under normal pressure or reduced pressure. .

Examples of the above-mentioned phenols include orthocresol, para-cresol, para-ethylphenol, para-propylphenol, para-tertiary-butylphenol, para-octylphenol and para-nonylphenol for bifunctional phenols, and trifunctional or higher functional phenols. Phenol, metacresol, bisphenol A, bisphenol F and the like, and one or more selected from these.

The formaldehydes include formaldehyde, paraformaldehyde, trioxane and the like, and they can be used in combination.

In the present invention, the organic acid metal salt used as a catalyst for reacting phenols with formaldehyde is one or two selected from divalent metal salts of organic acids.
More than one species, the organic acid includes carboxylic acid, naphthenic acid, sulfonic acid, and sulfinic acid, but carboxylic acid and naphthenic acid are particularly preferable, and the divalent metals include lead, calcium, manganese, and tin. , Zinc, copper,
Magnesium, barium and the like are preferable, but lead, manganese, zinc and barium are particularly preferable.

These catalysts are usually used as acid catalysts, such as inorganic acids such as hydrochloric acid and sulfuric acid and organic acids such as benzoic acid, salicylic acid, oxalic acid, maleic acid and paratoluenesulfonic acid, or two or more of them. It is also possible to use more than one species together. In addition, the reaction system is weakly acidic, usually at pH.
Alkali metal hydroxides and carbonates, alkaline earth metal hydroxides and oxides, and bases such as ammonia and amine compounds in order to obtain 3.5 to 6.8, preferably 4.5 to 6.0. A small amount of one or two or more of the sex catalysts may be used in combination.

The amount of the organic acid metal salt used in the above reaction is usually 0.000 per mol of the phenols.
It is 5 to 0.01 mol.

The phenol resin which is the component (C) in the present invention is acetylated and then analyzed by ¹ H-NMR (proton nuclear magnetic resonance) analysis. The ratio of the number of moles of methylene ether bond is 25% or more, preferably 30% or more. If it is less than 25%, no characteristic can be found in the workability of the obtained coating film and the adhesiveness to the article to be coated.

The above-mentioned phenol resin has a number average molecular weight of 200-200 by GPC (gel permeation chromatography).
It is preferably 2,000, and 250 to 1,500
Is more preferable.

In the conventional phenol resin for coating materials, the formaldehyde bonds to the phenol nucleus are mainly methylene bonds, and when the molecular weight is increased to improve the processability, the compatibility with the base resin is poor, and the article to be coated is It had the drawback of poor adhesion to In the present invention, when the phenol resin which is the component (C) is used in combination with the component (A) and, if necessary, the component (B), it is considered to be due to a dimethylene ether bond, but the above compatibility problem is solved. At the same time, the workability and the adhesion to the article to be coated are improved.

Further, the phenolic resin which is the component (C) of the present invention is less colored by oxidation than the conventional phenolic resin for paints obtained by reacting it under an alkaline condition with an alkali catalyst. It also has an advantage that the coloring of the paint used can be reduced.

In the composition of the present invention, the mixing ratio of the component (A) and the component (B) is such that the component (A) is contained in 100 parts by weight of the total amount of the component (A) and the component (B) in terms of solid content. 15
To 100 parts by weight, preferably 60 to 100 parts by weight,
The amount of the component (B) is 0 to 85 parts by weight, preferably 0 to 40 parts by weight. The amount of the component (C) is 1 in terms of solid content based on 100 parts by weight of the total of the components (A) and (B).
-50 parts by weight, preferably 5-30 parts by weight.
The amount of the component (A) is the sum of the components (A) and (B) 10
If it is less than 15 parts by weight out of 0 parts by weight, workability is deteriorated.
The amount of the component (C) is the sum of the components (A) and (B) 10
If it is less than 1 part by weight with respect to 0 part by weight, the curability will decrease,
Corrosion resistance and water resistance tend to decrease, while 50
If it exceeds the weight part, the workability tends to deteriorate and the hygienic property tends to deteriorate.

In the composition of the present invention, the above (A),
A modified resin in which the components (B) and (C) are dispersed or dissolved in an organic solvent, but can be dispersed or dissolved in an organic solvent in addition to the components (A), (B) and (C); pigments Various additives for coating materials such as anti-agglomeration agents, fluidity modifiers, antifoaming agents, etc. can be appropriately blended. The amount of the modified resin blended is preferably 30 parts by weight or less based on 100 parts by weight of the total of the components (A) and (B). The improving effect is usually exhibited at 5 parts by weight or more. When the modified resin is used for improving the processability, as the type, a polyolefin such as polybutadiene, epoxidized polybutadiene or modified vinyl resin having a static glass transition temperature of 0 ° C. or lower is preferable. Is.

As the organic solvent in the composition of the present invention,
Usually, it can be appropriately used from among the organic solvents used for paints. For example, alcohols such as ethanol, isopropanol, n-butanol and isobutanol; ether alcohols such as ethylene glycol monoethyl ether, ethylene glycol monobutyl ether and diethylene glycol monoethyl ether; aromatic hydrocarbons such as toluene and xylene; ethyl acetate ,
Examples thereof include esters such as butyl acetate; ketones such as acetone and methyl ethyl ketone.

The coating composition of the present invention can be applied to various substrates by various techniques known in the art. For example, the compositions of the present invention can be used in the can manufacturing industry, which primarily uses metal cans made of aluminum, chin-free steel, rolled electric field tin plates, and the like.

The cans used to package and ship food, coffee, beer and other beverages are primarily of the three-piece or two-piece stamping and ironing (D & I) type. Three-piece (main body,
Cans made from lids and bottoms) can be roll coated prior to forming the metal sheet into a can, or can be spray coated after partial forming.
D & I type cans, in which a metal sheet is stamped to form a closed end cylinder, are generally spray coated. The lid is typically roll coated. After the coating, it is generally dried at a temperature of about 90 to 330 ° C. for about 5 seconds to about 30 minutes.

[0043]

INDUSTRIAL APPLICABILITY The coating composition of the present invention is capable of forming a coating film having excellent flavor retention and processability, corrosion resistance, adhesiveness and hygiene, and particularly, can inner surface coating, easy coating. Suitable for painting open lids.

[0044]

EXAMPLES The present invention will be further clarified with reference to the following examples. Incidentally, in the following, simply, “part” and “%” mean “part by weight” and “% by weight”, respectively.

<Production of Phenol Resin Solution> Production Example 1 A reactor equipped with a stirrer, a reflux condenser and a thermometer was charged with 150 parts of phenol, 850 parts of paracresol, 583 parts of 80% paraformaldehyde and 300 parts of n-butanol. , Manganese acetate was added to adjust the pH of the reaction system to 6.2.
Then, the temperature was gradually raised. After the temperature reached 110 ° C., the mixture was reacted for 5 hours under reflux under normal pressure, and further reacted for 35-
Azeotropic dehydration was performed under a reduced pressure of 60 Torr. 40To
When the internal temperature reached 125 ° C. with rr, the dehydration reaction was terminated, and then diluted with ethylene glycol monobutyl ether to give a Gardner color number of 1, and a nonvolatile content (120% according to JIS K6909, hereinafter) when dried at 60 ° C. was 60. % Phenol resin solution (C-1) was obtained. According to the result of ¹ H-NMR analysis after acetylation of the phenol resin before solvent dilution, the molar ratio of the methylene bond according to the above formula [1] and the dimethylene ether bond according to the above formula [2] was found to be the same. : The latter ratio is 43:57, and the number average molecular weight by GPC (gel permeation chromatography) is about 1,
It was 280. The obtained phenolic resin had 2.0 methylol groups (including alkyl etherified ones) on average in one molecule.

Production Example 2 Paracresol 1,000 was added to a reactor of the same type as in Production Example 1.
Parts, 88% paraformaldehyde 400 parts, 37% formalin 550 parts and n-butanol 300 parts were charged, zinc acetate was added to adjust the pH of the reaction system to 5.1, and then the temperature was gradually raised. The mixture was reacted under reflux under normal pressure for 3.5 hours, and further dehydrated by azeotropic distillation under the same reduced pressure as in Production Example 1. When the internal temperature reached 125 ° C., the dehydration reaction was terminated, and then diluted with 3-methoxybutanol to give a Gardner color number of 1 and a nonvolatile content of 60 ° C. when dried at 120 ° C.
% Phenol resin solution (C-2) was obtained. The phenol resin before dilution with the solvent was treated with ¹ H-N as in Production Example 1.
According to the result of the MR analysis, the molar ratio of the methylene bond according to the formula [1] to the dimethylene ether bond according to the formula [2] was 5:95 in the former: the latter,
The number average molecular weight by PC was about 1,310. The obtained phenol resin had an average of 1.9 methylol groups (including those which were alkyl etherified) in one molecule.

Production Example 3 1,000 parts of para-tertiary butylphenol and 5% of 85% paraformaldehyde were placed in a reactor of the same type as in Production Example 1.
20 parts and 250 parts of n-butanol were charged, barium acetate was added to adjust the pH of the reaction system to 4.9, and then the temperature was gradually raised. After reacting under reflux under normal pressure for 5.0 hours, dehydration by azeotrope under normal pressure was carried out and the internal temperature was maintained at 123 ° C, then kept under reduced pressure of 30 Torr, and ended when the internal temperature reached 127 ° C. Then, a mixed solvent having a weight ratio of ethylene glycol monobutyl ether and butanol of 80:20 was added to obtain a phenol resin solution (C-3) having a Gardner color number of 1 and a nonvolatile content of 60% when dried at 120 ° C. . According to the result of ¹ H-NMR analysis of the phenol resin before solvent dilution as in Production Example 1, the molar ratio of the methylene bond according to the above formula [1] and the dimethylene ether bond according to the above formula [2] was shown. But the ratio of the former: the latter is 0:
The number average molecular weight by GPC is about 1,37.
It was 0. The obtained phenol resin had 2.1 methylol groups (including those which were alkyl etherified) on average in one molecule.

Production Example 4 (for comparison) Bisphenol A228 was used in the same reactor as in Production Example 1.
Parts, 486 parts of 38% formaldehyde aqueous solution and 70 parts of caustic soda were charged, the temperature was raised to 60 ° C. and the reaction was carried out for 3 hours. Then, 2.45 parts of sulfuric acid was added thereto, and 228 parts of n-butanol was further added thereto, and azeotropic dehydration was carried out by heating at a reduced pressure of 650 mmHg. After reducing the concentration to 80%, the solid content was diluted to 60% with n-butanol, and the bisphenol A trimethylol body was about 30% and the tetramethylol body was about 40%.
And a phenol resin solution (C-4) containing about 30% of a binuclear methylol compound bonded by a methylene bond as a main component
Got In the obtained resin, the average number of methylol groups per unit of bisphenol A was 3.0. The number average molecular weight by GPC was about 980.

Production Example 5 (for comparison) Bisphenol A228 was used in the same reactor as in Production Example 1.
Part, 38% formaldehyde aqueous solution 120.0 parts, water 9
7.7 parts and 2 parts of caustic soda were charged, the temperature was raised to 60 ° C. and the reaction was carried out for 3 hours. Then, 2.45 parts of sulfuric acid was added thereto, and 228 parts of n-butanol was added, and the degree of vacuum was 650.
Azeotropic dehydration was performed by heating at mmHg. After the pressure was reduced to 80%, the solid content was diluted to 60% with n-butanol, and about 80% of the bisphenol A monomethylol compound and about 20% of the methylene-bonded bisphenol A binuclear monomethylol compound were added. Phenol resin solution (C
-5) was obtained. In the obtained resin, the average number of methylol groups per unit of bisphenol A was about 0.8. The number average molecular weight by GPC was 350.

<Production of Phenoxy Resin Solution> Production Example 6 330 parts of PKHH (phenoxy resin manufactured by Union Carbide Co., number average molecular weight of about 25,000) was mixed with xylene / methyl isobutyl ketone / cellosolve 1/1/1 mixed solvent 670. To obtain a phenoxy resin solution (A-1) having a solid content of 33%.

Production Example 7 330 parts of Phenototo YP-50 (phenoxy resin manufactured by Tohto Kasei Co., Ltd., number average molecular weight of about 20,000) was added to xylene / methyl isobutyl ketone / cellosolve 1/1/1.
Was dissolved in 670 parts of the mixed solvent of to give a phenoxy resin solution (A-2) having a solid content of 33%.

<Production of Epoxy Resin Solution> Production Example 8 Epicoat 1009 (Epoxy resin manufactured by Shell Chemical Co., epoxy equivalent 3,500, number average molecular weight about 3,750) 3
30 parts were dissolved in 670 parts of a mixed solvent of xylene / methyl isobutyl ketone / cellosolve = 1/1/1 to obtain a solid content of 3
A 3% epoxy resin solution B was obtained.

Example 1 33% phenoxy resin solution (A-1) 3 obtained in Production Example 6
03 parts, 60% phenol resin solution obtained in Production Example 1 (C
-1) 16.7 parts and Modaflow (manufactured by Monsanto Co.,
A surface conditioner) 0.5PHR (0.55 part) was mixed to obtain a coating composition.

Examples 2 to 12 and Comparative Examples 1 to 3 Example 1 was the same as Example 1 except that the compounding amount of the resin obtained in Production Example (expressed as solid content) was as shown in Table 1 below. Each coating composition was obtained in the same manner. The notes in Table 1 are as follows. (Note 1) Epoxidized polybutadiene resin: Idemitsu Petrochemical Co., Ltd., epoxidized polybutadiene resin, trade name "R-4
5 EPI ", oxirane oxygen content 7.5% by weight, number average molecular weight about 2,800, static glass transition temperature about -78.
° C.

The coating compositions obtained in the above Examples and Comparative Examples were tested for adhesion of coating film, retort resistance, processability, flavor of water extract, and stability of coating composition with time. The test method was as follows. The test results are shown in Table 1 below.

Test method Preparation of test coated plate: An aluminum plate having a thickness of 0.3 mm was coated with a bar coater so that the dry coating film weight was 120 mg / 100 cm ^2, and after setting at 100 ° C. for 2 minutes,
A test plate was obtained by baking in a dryer for 30 seconds at an ambient temperature of 280 ° C. and a wind speed of 25 m / min so that the maximum temperature reached by the material was 260 ° C. This test plate was subjected to each test of adhesion, retort resistance, and workability. A water extract flavor was prepared in the same manner as the above test plate except that 0.1 mm thick aluminum foil was used instead of the 0.3 mm thick aluminum plate and the atmosphere temperature of the dryer was 275 ° C. A test plate for a sex test was obtained.

Adhesion: A knife is used to make 11 cuts in each of the vertical and horizontal directions with a knife on the coating surface of the test coated plate in the shape of a gobo. A cellophane adhesive tape with a width of 24 mm is adhered, and the adhesiveness of the eye area when strongly peeled off is observed. ◯: No peeling at all Δ: Slight peeling was observed ×: Significant peeling was observed Retort resistance: Test coated plate was immersed in deionized water at 125 ° C. for 3 times.
After soaking for 0 minute, the coating film is judged by the same evaluation method as the above adhesion test by peeling the cellophane adhesive tape. ◯: No peeling at all Δ: Slight peeling off ×: Significant peeling off

Workability: In a room at 20 ° C., using a special goby folding DuPont impact tester, two 0.3 mm-thick aluminum plates were placed between the bent portions of the test coated plate with the lower part folded in two. It is sandwiched, set in a tester, and the contact surface is flat with a thickness of 1 kg.
After dropping the iron weight of 50 cm from the height of 50 cm to give an impact to the bending part, energize the bending tip with an applied voltage of 6.5 V for 6 seconds, and the current value of the bending tip 20 mm width (mA) To measure. ◎: Less than 1mA ○: 1mA or more and less than 5mA △: 5mA or more and less than 10mA ×: 10mA or more

Flavorability of water extract: A test piece coated on an aluminum foil having a thickness of 0.1 mm was treated with activated carbon so that the amount of tap water treated with activated carbon was 1 ml per 1 cm ^{2 of} coating area. Put it in a glass bottle, cover it with 125
After sterilization at 30 ° C. for 30 minutes, a flavor test of the content liquid is performed. ◯: No change was observed at all Δ: There was a slight change ×: There was a significant change

[0060]

[Table 1]

Claims (3)

[Claims] 1. A method in which (C) phenols and aldehydes are reacted with 100 parts by weight of (A) 15 to 100 parts by weight of phenoxy resin and (B) 0 to 85 parts by weight of epoxy resin. A coating composition comprising 1 to 50 parts by weight of the following resole-type phenol-formaldehyde resin dispersed or dissolved in an organic solvent. The following general formula [1] or [2] [Chemical 2] [Wherein, R ¹ is the same or different and is a hydrogen atom, an alkyl group having 1 to 20 carbon atoms or the following general formula [3] (In the formula, R ² represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, R ³ is the same or different and represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and z represents 0 or 1.) Is a group represented by. ] The divalent group represented by the following is used as the repeating unit, and the number of units x of the group of the formula [1] in one molecule is 0 to
6, the number of units y of the group of the formula [2] is 2 to 14, and the sum of x and y is an integer of 4 to 20 and is substantially linear, and both ends of the molecule are The following general formula [4] (In the formula, R ¹ , R ² and z each have the above-mentioned meanings.) Resol type which is blocked by a group represented by the formula ( ¹ ) and the average sum of z per molecule is 1.0 to 3.0. Phenol / formaldehyde resin. 2. The compounding amount of (A) phenoxy resin and (B) epoxy resin is (B) 0 to 40 parts by weight with respect to (A) 60 to 100 parts by weight. 1
The coating composition described. 3. As the resin component, (D) a polyolefin having a static glass transition temperature of 0 ° C. or lower, which may be modified, is added to 100 parts by weight of the total of the (A) component and the (B) component. The coating composition according to claim 1 or 2, containing 5 to 30 parts by weight.