JP4131083B2 - Paint composition - Google Patents

Description

【００４１】
表１における（註）は、それぞれ下記のとおりの意味を有する。
（＊１）エピコート１００９：油化シェルエポキシ社製、ビスフェノールＡ型エポキシ樹脂、エポキシ当量３，５００、数平均分子量約３，７５０
（＊２）ＡＣ−３１６Ａ：アライドケミカル社製、酸化ポリエチレン
（＊３）Ｓ−３９４Ｎ−１：シャムロック社製、ポリエチレンワックス粉末
【００４２】
【発明の効果】
本発明の塗料組成物は、加工性、耐食性、密着性に優れ、かつ極めて潤滑性の高い塗膜を形成できる。従って、本発明塗料組成物は、特に、缶内外面、キャップ内外面などの被覆用塗料として適したものである。[0001]
BACKGROUND OF THE INVENTION
The present invention is a coating composition particularly suitable for inner and outer surface coating of cans and for inner and outer surface coating of caps, which can form a coating film excellent in adhesion, corrosion resistance, and workability with a metal material and excellent in slipping and scratch resistance. Related to things.
[0002]
[Prior art and problems]
Conventionally, epoxy-based paints are often used for thermosetting paints that are directly applied to metals because of their good adhesion to metals. In many cases, a lubricity-imparting agent is added to these paints so that the resulting coating film is not damaged and the frictional resistance when contacting with other materials does not increase. For example, polyolefin wax, silicone wax, fluoro wax, lanolin wax, montan wax, microcrystalline wax, carnauba wax, etc., but those usually used for imparting lubricity, excluding silicone wax, At room temperature, it is solid or pasty, and it is added to the paint as it is, or is dispersed or dissolved in a solvent in advance.
[0003]
However, these lubricity-imparting agents are not well-suited to resins generally used in paints, especially high-polarity resins such as epoxy resins, and the aggregation of lubricity-imparting agents tends to occur as the amount added increases. This causes various problems such as separation of paint, repelling / dentation during painting, and poor adhesion to the material. Furthermore, even if there is no problem at the initial stage, there are many cases where the lubricity-imparting agent gradually precipitates during storage of the paint and causes problems. Therefore, even when using an epoxy resin / phenolic resin crosslinking agent-based paint with excellent adhesion to metals, etc., and excellent workability, corrosion resistance, etc., the selection range of the type and amount of lubricity imparting agent to be added is limited. Therefore, it has been difficult to adapt to applications that require a high degree of sliding or scratch resistance.
[0004]
An object of the present invention is to provide a coating composition for obtaining a film having excellent adhesion to metal, workability and corrosion resistance, and excellent slip and scratch resistance.
[0005]
[Means for Solving the Problems]
As a result of intensive studies to solve the above problems, the present inventors have obtained a coating composition obtained by combining an epoxy resin / phenolic resin crosslinking agent system with a fatty acid ester that is liquid at room temperature below 10 ° C. The present inventors have found that the present invention is extremely useful for solving the above problems and have completed the present invention.
[0006]
That is, the present invention relates to (C) a fatty acid ester 1 having a freezing point of 10 ° C. or less with respect to 100 parts by weight of the sum of (A) 70 to 95 parts by weight of an epoxy resin and 5 to 30 parts by weight of a phenolic resin crosslinking agent. The present invention relates to a coating composition comprising 10 parts by weight.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
The coating composition of the present invention contains an epoxy resin (A), a phenol resin crosslinking agent (B), and a fatty acid ester (C) having a freezing point of 10 ° C. or lower.
[0008]
Epoxy resin (A)
Examples of the epoxy resin as the component (A) in the coating composition of the present invention include, for example, bisphenol type epoxy resins, novolak type epoxy resins, and modified products in which various modifiers are reacted with epoxy groups or hydroxyl groups in these epoxy resins. An epoxy resin etc. can be mentioned.
[0009]
Examples of the bisphenol-type epoxy resin include a resin obtained by condensing epichlorohydrin and bisphenol up to a high molecular weight in the presence of a catalyst such as an alkali catalyst, if necessary, and epichlorohydrin and bisphenol, if necessary, an alkali catalyst. Any of resins obtained by condensation in the presence of a catalyst such as a low molecular weight epoxy resin and a polyaddition reaction of the low molecular weight epoxy resin and bisphenol may be used.
[0010]
Examples of the bisphenol include bis (4-hydroxyphenyl) methane [bisphenol F], 1,1-bis (4-hydroxyphenyl) ethane, 2,2-bis (4-hydroxyphenyl) propane [bisphenol A], 2,2-bis (4-hydroxyphenyl) butane [bisphenol B], bis (4-hydroxyphenyl) -1,1-isobutane, bis (4-hydroxy-tert-butyl-phenyl) -2,2-propane, Examples thereof include p- (4-hydroxyphenyl) phenol, oxybis (4-hydroxyphenyl), sulfonylbis (4-hydroxyphenyl), 4,4′-dihydroxybenzophenone, and bis (2-hydroxynaphthyl) methane. The bisphenols can be used alone or as a mixture of two or more.
[0011]
Commercially available products of bisphenol type epoxy resins include, for example, Epicoat 1001, 1004, 1007, 1009, 1010 (all are manufactured by Yuka Shell Epoxy), AER6097, 6099 (all are Asahi Kasei Epoxy) And Epomic R-309 (Mitsui Chemicals).
[0012]
Examples of the novolac type epoxy resin include a phenol novolak type epoxy resin, a cresol novolac type epoxy resin, and a phenol glyoxal type epoxy resin having a large number of epoxy groups in the molecule.
[0013]
As a novolak type epoxy resin commercial product, for example, as a phenol novolak type, Epicoat 152, 154 (all of which are manufactured by Yuka Shell Epoxy Co., Ltd.), EPPN-201 (manufactured by Nippon Kayaku Co., Ltd.), Epototo YDPN-638 (Manufactured by Tohto Kasei Co., Ltd.) and the like, and as a cresol novolac type, Epicoat 180S65, 180H65 (all are manufactured by Yuka Shell Epoxy), EOCN-102S, -103S, -104S (all are above) Nippon Kayaku Co., Ltd.), Epototo YDCN-701, -702, -703, and -704 (all of which are manufactured by Tohto Kasei Co., Ltd.), and other novolac type epoxy resins include Epototo ZX-1071T. , ZX-1015, ZX-1247, YDG-414S (above, Displacement and the like is also manufactured by Toto Kasei Co., Ltd.).
[0014]
In addition, as the modified epoxy resin, a polymerizable unsaturated monomer component containing, for example, an epoxy ester resin obtained by reacting a dry oil fatty acid with the bisphenol type epoxy resin or novolak type epoxy resin, acrylic acid, methacrylic acid, or the like. Reacted epoxy acrylate resin, urethane-modified epoxy resin reacted with isocyanate compound, bisphenol-type epoxy resin, novolac-type epoxy resin, or epoxy group in the above-mentioned various modified epoxy resins, an amine compound is reacted with amino group or 4 Examples thereof include amine-modified epoxy resins obtained by introducing a quaternary ammonium salt.
[0015]
Among the above epoxy resins, bisphenol type epoxy resin and cresol novolac type epoxy resin, particularly preferably bisphenol A type epoxy resin and bisphenol F type epoxy resin are suitable from the viewpoint of adhesion and workability of the coating film.
[0016]
Phenolic resin crosslinking agent (B)
The phenol resin crosslinking agent which is the component (B) in the coating composition of the present invention is blended for crosslinking and curing with the epoxy resin (A).
[0017]
Examples of the phenol resin cross-linking agent (B) include a resol type phenol resin in which a phenol and a formaldehyde are heated and condensed in the presence of a reaction catalyst to introduce a methylol group. The introduced methylol group may be alkyl etherified.
[0018]
The phenols used for the production of the phenol resin crosslinking agent include bifunctional phenols such as o-cresol, p-cresol, p-tert-butylphenol, p-ethylphenol, 2,3-xylenol, and 2,5-xylenol. ; Trifunctional phenols such as phenol, m-cresol, m-ethylphenol, 3,5-xylenol, m-methoxyphenol; tetrafunctional phenols such as bisphenol A and bisphenol F, and the like. , Or a mixture of two or more.
[0019]
Examples of formaldehydes used in the production of the phenol resin cross-linking agent include formaldehyde, paraformaldehyde, or trioxane, and these can be used alone or in combination of two or more.
[0020]
As the alcohol used for alkyl etherifying a part of the methylol group of the methylolated phenol resin, a monohydric alcohol having 1 to 8 carbon atoms, preferably 1 to 4 carbon atoms is suitable. For example, methanol, ethanol , N-butanol, isobutanol, etc., among which methanol is particularly preferable.
[0021]
In the composition of the present invention, a tough film can be obtained by crosslinking the epoxy resin (A) and the phenol resin crosslinking agent (B). From the viewpoint of adhesion of the film to the material, workability, etc., both Based on the total solid content of 100 parts by weight, the amount of the epoxy resin (A) is 70 to 95 parts by weight, preferably 80 to 90 parts by weight, and the amount of the phenol resin crosslinking agent (B) is 5 to 30. It is suitable to be in the range of parts by weight, preferably 10-20 parts by weight.
[0022]
Fatty acid ester (C) with a freezing point of 10 ° C or lower
The fatty acid ester having a freezing point of 10 ° C. or lower, which is the component (C) in the composition of the present invention, is blended for the purpose of improving the lubricity of the resulting film.
[0023]
The fatty acid ester means an esterified product of a polyol compound and a fatty acid. Among these, fatty acid esters which are liquid at normal temperature of 10 ° C. or less have little adverse effect on storage stability, coating workability, adhesion to metal, etc. due to addition to the epoxy resin / phenolic resin crosslinking agent coating system. In addition, the effect of increasing the lubricity is particularly great. Depending on the application, it can be selected in consideration of those with little alteration due to oxidation, those with as little odor as possible, etc., but from the point that safety has been confirmed, naturally occurring plant or animal nature Is particularly suitable for food cans. From the viewpoint of being difficult to oxidize, those having a small iodine value that is a standard for the content of unsaturated double bonds in the fatty acid ester are preferable, and those having an iodine value of 100 or less, generally called non-drying oil, are suitable. In addition, vegetable oils are suitable from the viewpoint of odor, and more preferably those are well purified. Representative vegetable oils that are less oxidized and less odorous include, for example, refined olive oil and refined cocoon oil.
[0024]
The addition amount of the fatty acid ester (C) having a freezing point of 10 ° C. or less is 1 to 10 parts by weight, preferably 2 to 5 parts by weight based on 100 parts by weight of the total of the epoxy resin (A) and the phenol resin crosslinking agent (B). It is suitable to be within the range of the part.
[0025]
Moreover, the lubricity imparting agent used conventionally can also be used in combination with the fatty acid ester (C) having a freezing point of 10 ° C. or lower. For example, silicon wax, fluorine wax, polyolefin wax, lanolin wax, montan wax, paraffin wax, microcrystalline wax, carnauba wax and the like are mentioned. Among them, lanolin wax, microcrystalline wax and carnauba wax are preferable. Depending on the type and amount of addition, these waxes may cause various problems such as paint separation, coating surface abnormalities during coating, and poor adhesion of the coating as described above. is there.
[0026]
The coating composition of the present invention comprises an epoxy resin (A), a phenol resin cross-linking agent (B) and a fatty acid ester (C) having a freezing point of 10 ° C. or lower as essential components. A solvent is blended. The composition of the present invention further contains conventionally known paint additives such as curing catalysts, color pigments, extender pigments, rust preventive pigments, anti-aggregation agents, leveling agents, antifoaming agents, and UV absorbers as necessary. be able to.
[0027]
As said solvent, what can melt | dissolve or disperse | distribute each component, such as said component (A), (B) and (C), can be used, for example, toluene, xylene, a high boiling point petroleum hydrocarbon etc. Hydrocarbon solvents, ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, isophorone, ester solvents such as ethyl acetate, butyl acetate, ethylene glycol monoethyl ether acetate, diethylene glycol monoethyl ether acetate, methanol, ethanol, butanol And alcohol solvents such as ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, and ether alcohol solvents such as diethylene glycol monobutyl ether. It can be used as a mixture of at least species.
[0028]
The coating composition of the present invention can be applied to various objects such as metal plates, plastics, glass plates, etc., and in particular, the outer surface and / or the inner surface of a can or cap processed on the metal plate or the metal plate. By coating and baking, a coating film suitable for can or cap coating can be formed.
[0029]
As the metal plate used for the can or cap, any metal plate can be used as long as it can be used for beverage cans, cans for cans, caps, etc. For example, aluminum plate, tin-free steel plate, tin plate Etc.
[0030]
The coating composition of the present invention can be applied by a known coating method such as roll coater coating or spray coating. The coating film thickness is not particularly limited, but is preferably about 1 to 20 μm in terms of dry film thickness. The baking condition of the coating film is usually about 15 seconds to about 15 minutes under the condition that the maximum temperature reaches about 90 to 300 ° C. for a metal plate.
[0031]
【Example】
Hereinafter, the present invention will be described more specifically with reference to examples. Hereinafter, both “parts” and “%” are based on weight.
[0032]
Example 1
Epicoat 1007 (manufactured by Yuka Shell Epoxy Co., Ltd .: bisphenol A type epoxy resin, epoxy equivalent 1,700, number average molecular weight 2,900) of 330 parts of xylene / methyl isobutyl ketone / cellosolve = 1/1/1 (weight ratio) An epoxy resin solution having a solid content of 33% was obtained by dissolving in 670 parts of the mixed solvent. To 258 parts of the epoxy resin solution, 36 parts of hitanol 3305N (manufactured by Hitachi Chemical Co., Ltd .: phenol resin solution, solid content 42%) and 3 parts of purified olive oil were mixed, and methyl ethyl ketone / cyclohexanone = 1/1 (weight ratio). A solvent was added to obtain a paint having a solid content of 30%.
[0033]
Examples 2-6 and Comparative Examples 1-6
Except for the formulation shown in Table 1 below, the same procedure as in Example 1 was performed to obtain each paint having a solid content of 30%. The blending amount of each resin component in Table 1 is based on solid content display.
[0034]
Preparation of test coating plate The paint obtained in the above Examples and Comparative Examples was applied to a # 3105 aluminum plate having a thickness of 0.24 mm so that the dry film thickness was 4 μm, and hot air with a wind speed of 3 m / second was used. A test coated plate was obtained by baking for 10 minutes under the condition that the material maximum temperature (PMT) was 200 ° C. The obtained test coated plate was tested based on the following test method. The test results are shown in Table 1 below.
[0035]
Test method Coating film appearance: The coating film appearance of the test coating plate was observed with the naked eye. A coating having no coating surface abnormality such as repellency, dents, or cloudiness on the coating surface was evaluated as good (◯).
[0036]
Adhesion: According to JIS K-5400 8.5.2 (1990) grid pattern-tape method, 11 parallel vertical and horizontal lines are formed so that the surface of the coating film on the test plate reaches the substrate with a cutter knife. 100 straight lines of 1.5 mm × 1.5 mm were created by drawing straight lines at 1.5 mm intervals. A cellophane adhesive tape was brought into close contact with the surface, and the degree of peeling of the cells when the tape was rapidly peeled was observed and evaluated according to the following criteria.
○: No peeling of the coating film is observed.
(Triangle | delta): Although a coating film peels slightly, 90 or more squares remain | survive.
X: The coating film peeled off considerably, and the number of cells remaining was less than 90.
[0037]
Workability: A cup was prepared by using a punch with a diameter of 33 mm using a deep drawing tester manufactured by Eriksen Co., Ltd., with a blank diameter of 60 mm and a coating film on the outer surface side. After the cup was immersed in boiling water at 100 ° C. for 1 hour, an adhesion test was performed on the processed side surface portion. The evaluation criteria are as follows.
○: No peeling of the coating film is observed.
Δ: Slight peeling of coating film is observed.
X: Remarkable peeling of the coating film is observed.
[0038]
Pencil hardness: A pencil scratch test specified in JIS K-5400 8.4.2 (1990) was performed on the coating film of the test coating plate. Evaluation was carried out by the shake method.
[0039]
Lubricity: Egan Slip Tester Model No.225-3 (manufactured by Swing Albert Instrument Company) [Egan Slip Tester Model No.225-3 (manufactured by Thing Albert Instrument Co.)] Then, the dynamic friction coefficient was measured under the condition of a pulling speed of 10 cm / min. The smaller the dynamic friction coefficient, the better the lubricity.
[0040]
[Table 1]

[0041]
(註) in Table 1 has the following meanings.
(* 1) Epicoat 1009: manufactured by Yuka Shell Epoxy, bisphenol A type epoxy resin, epoxy equivalent 3,500, number average molecular weight about 3,750
(* 2) AC-316A: manufactured by Allied Chemical, polyethylene oxide (* 3) S-394N-1: manufactured by Shamrock, polyethylene wax powder
【The invention's effect】
The coating composition of the present invention is excellent in processability, corrosion resistance and adhesion, and can form a coating film having extremely high lubricity. Therefore, the coating composition of the present invention is particularly suitable as a coating material for coating inner and outer surfaces of cans and inner and outer surfaces of caps.

Claims (1)

(A) A plant having an iodine value of 100 or less, which is a fatty acid ester having a freezing point of 10 ° C. or less, with respect to 100 parts by weight of the sum of 70 to 95 parts by weight of epoxy resin and (B) 5 to 30 parts by weight of a phenol resin cross-linking agent A coating composition for coating the inner and outer surfaces of the can and the inner and outer surfaces of the cap, comprising 1 to 10 parts by weight of a functional oil or fat .