JPH11323217A - Printing ink composition and covering method using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a printing ink composition capable of being diluted in a hydrocarbon-based solvent without giving any effect to a flavorous property to a can ingredient by including a pigment, an alkyd resin, a hydrocarbon-based solvent and others at a specific ratio. SOLUTION: This printing ink composition is obtained by including (A) A wt.% of a pigment, (B) B wt.% of an alkyd resin having E of an iodine value and >=20, preferably 20-50, more preferably 30-45 of an oil length, (C) C wt.% of a hydrocarbon-based solvent preferably containing an aromatic hydrocarbon and (D) D wt.% of the others (A+B+C+D=100) so as to satisfy (B×E)<=1,000. Preferably, a resin containing a condensation product of a polybasic acid with a polyhydric alcohol as a principal skeleton and modified with an oil, a fatty acid or their hydrogen added material, a monofunctional acid, a monohydric alcohol, etc., is used as the component B. Preferably, a nondrying oil (e.g. coconut oil) and/or a nondrying fatty acid (e.g. coconut oil fatty acid) is used as the oil and/or fatty acid.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

FIELD OF THE INVENTION The present invention relates to the field of printing inks, and more particularly, to printability in two-piece can printing inks.
Can be diluted in hydrocarbon solvents that do not adversely affect physical properties,
An object of the present invention is to provide a printing ink composition which does not affect the flavor of the contents, and which provides sufficient curability even when a varnish for aqueous overprint is combined, and a coating method using the same.

[0002]

2. Description of the Related Art At present, printing of two-piece cans around the world is increasingly performed using ink composed of a pigment, an oil-free polyester resin, and an alcohol-based solvent. However, in Japan, there are many cans that require retort properties, such as coffee and tea, so that inks composed of an oil-free polyester resin and an alcohol-based solvent have problems in physical properties such as retort resistance. In addition, the use of printing is restricted due to problems such as poor misting and poor working environment in terms of printability.

[0003] In Japan, therefore, an ink mainly comprising a hydrocarbon-based solvent which does not adversely affect physical properties and printability, an alkyd resin and a pigment which can be dissolved in the solvent is used. As the alkyd resin, a drying oil such as soybean oil, dehydrated castor oil, and linseed oil is used from the viewpoint of curability, and the oil length is 50 or more. However, there is a problem that the flavor of the contents of the can, which is considered to be caused by the unsaturated double bond of the oil, is inferior to that of the oil-free polyester.

Further, in recent years, from the viewpoint of environmental protection, varnishes for aqueous overprinting have been increasingly used. However, since the water-based overprint varnish has a poor gas barrier property as compared with the solvent-type overprint varnish, it has become a major problem that the alkyd resin has a poor flavor to the contents of the can as compared to the oil-free polyester. . On the other hand, the oil-free polyester does not dissolve in a hydrocarbon-based solvent that does not adversely affect the physical properties and printability, so that it has to be dissolved in an alcohol-based solvent having poor misting and poor water resistance before use.

[0005] As ink compositions for two-piece cans, there are ink compositions described in JP-A-2-24315 and JP-A-2-127485, which are basically concerned with oil-free polyesters. It is difficult to dissolve in a hydrocarbon-based solvent that does not adversely affect the physical properties and printability, and the printability and physical properties are not sufficiently satisfactory.

JP-A-50-73710 describes an ink composition using an alkyd resin using a non-drying oil, but uses a solvent-type overprint varnish having good gas barrier properties. No consideration is given to controlling the flavor of the contents of the can. Also, in terms of curability, the use of aqueous varnishes for aqueous overprints is not considered, because it does not consider the use of varnishes for aqueous overprints, which are more susceptible to the oil length and type of ink used in combination than solvent-based overprint varnishes. Use in combination is difficult.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, and an object of the present invention is to provide an aqueous overprint which can be diluted with a hydrocarbon solvent which does not adversely affect physical properties and printability. An object of the present invention is to provide a printing ink composition which can obtain sufficient curing even when combined with a varnish for use and does not affect the flavor of the contents of a can, and a coating method using the same.

[0008]

Means for Solving the Problems The present inventors have conducted intensive studies and found that pigment, A weight%, alkyd resin, B weight%,
Hydrocarbon solvent, C weight%, other, D weight% (A + B
+ C + D = 100) By setting B × E ≦ 1000 (E is the iodine value of the alkyd resin) in the printing ink composition consisting of: + C + D = 100, a printing ink excellent in printability having little influence on the flavor of the content is obtained. The inventors have found that the present invention can be obtained, and have completed the present invention.

That is, the present invention relates to a printing ink composition comprising a pigment, A weight%, an alkyd resin, B weight%, a hydrocarbon solvent, C weight%, and D weight% (A + B + C + D = 100). The present invention relates to a printing ink composition characterized in that B × E ≦ 1000 (E is an iodine value of an alkyd resin) and a coating method using the same.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, each component used in the present invention will be described in detail. The alkyd resin used in the present invention has a skeleton of a condensate of a polybasic acid and a polyhydric alcohol, and has an oil, a fatty acid or a hydrogenated product thereof, a monovalent acid,
It is a resin modified with a monohydric alcohol or the like, and can be modified with an epoxy resin or an acrylic resin. When each component is made into an ink, the pigment, A weight%, alkyd resin, B weight%, hydrocarbon solvent, C weight%, etc.
In the composition of D weight% (A + B + C + D = 100),
Any material can be used as long as it can be adjusted to B × E ≦ 1000 (E is the iodine value of the alkyd resin), and raw materials that can be generally used for synthesizing the alkyd resin can be used, and there is no particular limitation.

Examples of polybasic acids include adipic acid, phthalic anhydride, isophthalic acid, terephthalic acid, succinic anhydride, azelaic acid, sebacic acid, tetrahydrophthalic anhydride,
Hexahydrophthalic anhydride, tetrabromophthalic anhydride, tetrachlorophthalic anhydride, hetic anhydride, hymic anhydride, maleic anhydride, fumaric acid, itaconic acid,
Examples thereof include trimellitic anhydride, methylcyclohexenetricarboxylic anhydride, pyromellitic anhydride and the like, and they can be used alone or as a mixture of two or more.

Examples of polyhydric alcohols include ethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, butylene glycol,
Hexanediol, neopentyl glycol, octanediol, butylethylpropanediol, bisphenol A, hydrogenated bisphenol A, bisphenol F,
Glycerin, trimethylolethane, trimethylolpropane, trishydroxymethylaminomethane, pentaerythritol, dipentaerythritol and the like can be exemplified, and they can be used alone or in combination of two or more.

As oils and fatty acids, when made into inks,
Pigment, A weight%, alkyd resin, B weight%, hydrocarbon solvent, C weight%, other, D weight% (A + B + C + D
= 100), there is no particular limitation as long as it can be adjusted to B × E ≦ 1000 (E is the iodine value of the alkyd resin). Oils commonly used in alkyd resin synthesis,
Fatty acids can be used. Linseed oil, tung oil, dehydrated castor oil, soybean oil, safflower oil, bran oil, tall oil, linseed oil fatty acid, tung oil fatty acid, dehydrated castor oil fatty acid, soybean oil fatty acid, safflower oil fatty acid, nuka oil, tall oil fatty acid, etc. Can be used singly or as a mixture of a plurality of them. However, in order to adjust B × E ≦ 1000, it is preferable to use a non-drying oil and / or a non-drying oil fatty acid.

Examples of the non-drying oil and the non-drying oil fatty acid include castor oil, palm oil, coconut oil, castor oil fatty acid, palm oil fatty acid, and coconut oil fatty acid. Further, in consideration of price, availability and the like, it is desirable to use coconut oil and / or coconut oil fatty acid.

[0015] Other fatty acids include pelargonic acid,
Capric acid, undecanoic acid, lauric acid, tridecanoic acid, myristic acid, pentadecanoic acid, palmitic acid, margaric acid, stearic acid, isostearic acid, oleic acid, linoleic acid, linolenic acid, and the like can be used in combination.

Examples of the monovalent acid include benzoic acid, p-tert-butylbenzoic acid, rosin acid, hydrogenated rosin acid and the like, and they can be used alone or in combination. Examples of the monohydric alcohol include octyl alcohol, decanol, lauryl alcohol, cetyl alcohol, stearyl alcohol, isostearyl alcohol, glycol esters, glycol ethers such as phenyl glycol, rosin alcohol, hydrogenated rosin alcohol, and the like. A plurality can be mixed and used.

As the epoxy modification, it is also possible to form an epoxy ester with a compound having a monovalent and / or polyvalent epoxy group and modify it. As the acryl modification, acryl modification using styrene is also possible.

The oil length of the alkyd resin of the present invention, when converted into an ink, is as follows: pigment, A weight%, alkyd resin, B weight%, hydrocarbon solvent, C weight%, other D weight% (A
+ B + C + D = 100), B × E ≦ 10
There is no particular limitation as long as the varnish can be adjusted to 00 (E is the iodine value of the alkyd resin). However, the varnish for aqueous overprint is baked on the printing ink composition of the present invention by adjusting to B × E ≦ 1000. In order to ensure the hardness of the composite film after the above, the oil length of the alkyd resin of the present invention should be 5
It is desirably 0 or less. In order to dissolve the alkyd resin of the present invention in a hydrocarbon solvent, the oil length must be 2
Desirably, it is 0 or more. That is, the oil length of the alkyd resin of the present invention is desirably in the range of 20 to 50. More preferably, it is 30 to 45.

The amount of the alkyd resin of the present invention, when converted into an ink, is as follows: pigment, A weight%, alkyd resin, B weight%, hydrocarbon solvent, C weight%, other D weight%
In the composition of (A + B + C + D = 100), B × E ≦
There is no particular limitation as long as it can be adjusted to 1000 (E is the iodine value of the alkyd resin), but it is preferably 5% by weight or more from the viewpoint of the solubility in hydrocarbon solvents.

As the hydrocarbon solvent used in the present invention, there can be used a hydrocarbon solvent having a boiling point in the range of 200 to 400 ° C. and usually used for inks, and there is no particular limitation. If the boiling point is less than 200 ° C., there is a problem in on-press stability on a printing press, and if it exceeds 400 ° C., it remains in the coating at the time of baking and drying, causing problems in physical properties.

In order to dissolve the alkyd resin of the present invention and improve the coatability of the aqueous varnish for overprint,
It is desirable that the hydrocarbon solvent of the present invention contains an aromatic hydrocarbon having relatively high surface tension and good solubility. Examples of the aromatic hydrocarbon include an alkylbenzene containing one aromatic ring and having a linear or branched alkyl group, phenylxylylethane, hydrogenated triphenyl and the like, and can be used alone or in combination of two or more.

The amount of the hydrocarbon solvent to be used in the present invention is usually determined by the T.T. There is no particular limitation as long as V (tack value) can be adjusted in the range of 2 to 20, but it is usually in the range of 5 to 60% by weight.

As the pigment used in the present invention, any inorganic and organic pigments can be used alone or in combination.

As other components of the present invention, a pigment dispersant, a drier, an acid catalyst, an auxiliary resin, an auxiliary solvent, and the like can be added as necessary.

As the auxiliary resin, any resin may be used alone or in combination of two or more depending on printability, physical properties and the like.
Examples thereof include a rosin-modified phenol resin, an oil-free polyester resin, a petroleum resin, an epoxy resin, a ketone resin, a rosin-modified maleic resin, an amino resin, and a benzoguanamine resin.

The auxiliary solvent may be used alone or in combination of two or more depending on printability and coatability of the varnish for overprint. Examples thereof include glycol-based, glycol ether-based, glycol ester-based, and higher alcohol-based solvents.

The printing ink composition of the present invention can be easily printed by a usual two-piece can printing method such as a dry offset method. The ink film thickness is optional, but may be, for example, in the range of 0.3 to 6 microns.

As the overprint varnish to be combined with the printing ink composition of the present invention, any water-based or solvent-type overprint varnish usually used for print coating of two-piece cans which is cured by heating can be used. Absent.

The method for curing the varnish for overprinting combined with the printing ink composition of the present invention is basically the same as that of the conventional varnish after printing and coating by a wet-on-wet method.
As in the case of a piece can, baking and drying may be performed at 180 to 210 ° C. for 5 to 180 seconds.

The coating method of the varnish for overprinting combined with the printing ink composition of the present invention can be carried out by a usual coater method. The thickness of the overprint varnish is optional, but may be, for example, in the range of 5 to 10 microns.

[0031]

EXAMPLES The present invention will be described below in detail with reference to examples to facilitate understanding of the present invention. The parts and percentages in the examples are based on weight.

(Synthesis of alkyd resin 1) 35 parts of coconut oil fatty acid, 29 parts of phthalic anhydride, 20 parts of trimethylolpropane and 16 parts of pentaerythritol were esterified by a conventional method to obtain a liquid alkyd resin having an oil length of 35. . The iodine value of this resin was 4. (The iodine value was measured in accordance with JIS K 5407. The same applies hereinafter.)

(Synthesis of alkyd resin 2) 60 parts of coconut oil fatty acid, 19 parts of phthalic anhydride and 21 parts of pentaerythritol were esterified by a conventional method to obtain a liquid alkyd resin having an oil length of 60. The iodine value of this resin was 6.

(Synthesis of alkyd resin 3) 15 parts of coconut oil fatty acid, 39 parts of phthalic anhydride, 25 parts of trimethylolpropane and 21 parts of pentaerythritol were esterified by a conventional method to obtain a liquid alkyd resin having an oil length of 15. . The iodine value of this resin was 2.

(Synthesis of alkyd resin 4) 35 parts of soybean oil fatty acid, 29 parts of phthalic anhydride, 20 parts of trimethylolpropane and 16 parts of pentaerythritol were esterified by a conventional method to obtain a liquid alkyd resin having an oil length of 35. . The iodine value of this resin was 42.

(Synthesis of alkyd resin 5) 60 parts of a soybean oil fatty acid, 19 parts of phthalic anhydride and 21 parts of pentaerythritol were esterified by a conventional method to obtain a liquid alkyd resin having an oil length of 60. The iodine value of this resin was 72.

(Synthesis of alkyd resin 6) 15 parts of soybean oil fatty acid, 39 parts of phthalic anhydride, 25 parts of trimethylolpropane and 21 parts of pentaerythritol were esterified by a conventional method to obtain a liquid alkyd resin having an oil length of 15. . The iodine value of this resin was 18.

(Synthesis of Alkyd Resin 7) Resin 150
Part and resin 450 parts, iodine value of this resin is 20
Met.

(Preparation of Example Ink 1) 20 parts of Fastogen Blue TGR-L (pigment manufactured by Dainippon Ink and Chemicals),
40 parts of an alkyd resin 1 and 40 parts of an alkene 60NH (alkylbenzene made by Nippon Oil Co., Ltd.) were kneaded and stirred with a usual three-roll mill to obtain a blue ink. B × E = 16
0.

(Preparation of Example Ink 2) 20 parts of Fastogen Blue TGR-L (pigment manufactured by Dainippon Ink and Chemicals),
40 parts of alkyd resin 7 40 parts of alkene 60NH (Alkylbenzene made by Nippon Oil Co., Ltd.) were mixed and stirred with a usual three-roll mill to obtain a blue ink. B × E = 80
0.

(Preparation of Comparative Example Ink 1) 20 parts of Fastogen Blue TGR-L (a pigment manufactured by Dainippon Ink and Chemicals),
40 parts of alkyd resin 2 and 40 parts of alkene 60NH (alkylbenzene made by Nippon Petroleum Co., Ltd.) were kneaded and stirred with a usual three-roll mill to obtain a blue ink. B × E = 24
0.

(Preparation of Ink 2 for Comparative Example) 20 parts of Fastogen Blue TGR-L (pigment manufactured by Dainippon Ink and Chemicals),
40 parts of alkyd resin 3 and 40 parts of alkene 60NH (alkylbenzene, manufactured by Nippon Oil Co., Ltd.) were kneaded and stirred with a usual three-roll mill to obtain a blue ink. B × E = 80
It is.

(Preparation of Comparative Example Ink 3) 20 parts of Fastogen Blue TGR-L (pigment manufactured by Dainippon Ink and Chemicals),
40 parts of alkyd resin 4 and 40 parts of alkene 60NH (alkylbenzene made by Nippon Oil) were kneaded and stirred with a usual three-roll mill to obtain a blue ink. B × E = 16
80.

(Preparation of Comparative Ink 4) 20 parts of Fastogen Blue TGR-L (pigment manufactured by Dainippon Ink and Chemicals),
40 parts of an alkyd resin 5 and 40 parts of an alkene 60NH (alkyl benzene made by Nippon Oil Co., Ltd.) were kneaded and stirred with a usual three-roll mill to obtain a blue ink. B × E = 28
80.

(Preparation of Ink 5 for Comparative Example) 20 parts of Fastogen Blue TGR-L (pigment manufactured by Dainippon Ink and Chemicals),
Forty parts of alkyd resin 6 and 40 parts of alkene 60NH (alkylbenzene made by Nippon Oil) were kneaded and stirred with a usual three-roll mill to obtain a blue ink. B × E = 72
0.

(Solubility test) An appropriate amount of each of the inks of Examples 1 and 2 and Comparative Inks 1 to 5 was placed on a slide and left at 10 ° C. for 24 hours, and the appearance was visually observed. When the ink on the preparation was inhomogeneous due to the tendency of the solvent to separate, the ink was evaluated as x, and the homogeneous ink was evaluated as ○.

(Curability Test) Each of the inks of Examples 1 and 2 and Comparative Inks 1 to 5 was printed on an aluminum plate (thickness of 50 to 100 μm) with an RI tester so that the ink film thickness was 1.5 μm. Aqueous overprint varnish, 2W-131 (manufactured by Dainippon Ink and Chemicals, Inc.) was baked with the ink in a wet state following printing, and the coating amount after baking was 45 m.
g / 100 cm2. 200 ° C for 45 seconds + 200 ° C
Baking and drying were performed for 90 seconds (peak temperature). The hardness of the obtained printed coated plate was evaluated by a JIS K 5400 pencil scratch test. A mark with a pencil of H on the coating surface of the printed painted plate was evaluated as x, and a mark with no scratch was evaluated as ○.

(Flavor test) Example inks 1-2
Comparative Examples Inks 1 to 5 were printed on an aluminum plate (50 to 100 μm thick) with an RI tester so that the ink film thickness was 1.5 μm. This printing plate was cut into a size of 250 cm 2, placed on a hot plate at 200 ° C., and the generated volatiles were adsorbed and collected on a 250 cm 2 aluminum foil. This aluminum foil was placed in a glass bottle containing 500 cc of tap water subjected to activated carbon treatment, and then closely retorted at 125 ° C. for 30 minutes. The flavor of the treated tap water was compared with the activated carbon treated tap water. Compared with the tap water treated with activated carbon, the tap water after treatment was evaluated as x when the change in the flavor was remarkable, and as small when the change was small.

[0049]

[Table 1]

[0050]

The pigment of the present invention, A weight%, alkyd resin, B weight%, hydrocarbon solvent, C weight%, etc.
In a printing ink composition consisting of% by weight (A + B + C + D = 100), B × E ≦ 1000 (E is an iodine value of an alkyd resin). It does not adversely affect water resistance, such as retort properties, etc., can be stably dissolved in hydrocarbon solvents, and when used in combination with a varnish for aqueous overprinting, it has sufficient hardness and can be used as a flavor for can contents. Is an excellent ink composition that hardly affects the ink composition.

Claims (6)

[Claims] 1. Pigment, A weight%, alkyd resin, B weight%, hydrocarbon solvent, C weight%, other, D weight%
A printing ink composition comprising (A + B + C + D = 100), wherein B × E ≦ 1000 (E is an iodine value of an alkyd resin). 2. The printing ink composition according to claim 1, wherein the alkyd resin contains a non-drying oil and / or a non-drying oil fatty acid. 3. The printing ink composition according to claim 1, wherein the non-drying oil is coconut oil, and the non-drying oil fatty acid is coconut oil fatty acid. 4. The printing ink composition according to claim 1, wherein the oil length of the alkyd resin is in the range of 20 to 50. 5. The printing ink composition according to claim 1, wherein the hydrocarbon solvent contains an aromatic hydrocarbon. 6. An overprint varnish having a thermosetting property is applied to a printing surface printed using the printing ink composition according to claim 1 before curing of the ink.
A coating method characterized by heating and curing.