JPH08894B2 - Printing ink for metal - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing ink for metals, and more specifically, in a printing method in which after printing the ink, an aqueous type overprint varnish is wet coated in a wet state of the ink and baked from above. The present invention relates to a metal printing ink exhibiting excellent printability and coating film physical properties.

[0002]

2. Description of the Related Art Conventionally, a polyester resin has been known as a printing ink for metals, and for example, one using a polyester resin containing rosin alcohol as an essential component (JP-A-2-24315) has been proposed.

[0003]

However, in the above printing method, the conventional printing ink containing a polyester resin is suitable for an aqueous type overprint varnish, that is, repelling of the varnish on the ink coating surface, There was a problem that the varnish submerged in the ink film, resulting in lack of gloss or adhesion, and insufficient coating film physical properties, especially coating film hardness.

[0004]

[Means for Solving the Problems] The inventors of the present invention have made earnest studies to obtain a printing ink for metals which is excellent in suitability for an aqueous overprint varnish (no cissing or dipping) and which gives a suitable coating hardness. As a result, repelling can be prevented by using a compound to which an alkylene oxide has been added as a polyol component in order to impart an affinity to an aqueous overprint varnish, and the viscosity of the polyester resin can be reduced to reduce unnecessary diluent solvent. As a result, they have found that it is possible to prevent diving, and have reached the present invention.

That is, according to the present invention, as a resin component, a polyol component comprising an alkylene oxide adduct (a) of a bisphenol and an alkylene oxide adduct (b) of an aliphatic polyhydric alcohol, and a carboxylic acid (c).
A printing ink for metal, which comprises using a polyester (A) obtained by reacting with and an amino resin (B), and the content of (A) is 10 to 70% by weight based on the total amount of the printing ink. (I).

The present invention is a printing ink composition mainly composed of a pigment, a resin and a solvent, and as a resin component, an alkylene oxide adduct (a) of a bisphenol and an alkylene oxide adduct (b) of an aliphatic polyhydric alcohol. A polyester (A) obtained by reacting a polyol component consisting of carboxylic acid (c) with
And an amino resin (B), and the content of (A) with respect to the total amount of the printing ink is 10 to 70% by weight.

(A) in the printing ink (I) of the present invention
Examples of the bisphenols include bisphenol A, bisphenol B, bisphenol S, methylene bisphenol, and the like, and their derivatives (styrenized products, alkylated products, etc.).

(A) is obtained by adding one or more alkylene oxides (ethylene oxide, propylene oxide, butylene oxide, etc.) to bisphenols, and the number of added alkylene oxides is usually 1 to 1000 mol, preferably 3 to. 200 mol, more preferably 3-5
It is 0 mol.

The alkylene oxide constituting (a) is preferably ethylene oxide and / or propylene oxide.

The alkylene oxide adducts (b) of polyhydric alcohols include dihydric alcohols (ethylene glycol, propylene glycol, neopentyl glycol, etc.), trihydric and higher alcohols (glycerin, butanetriol, trimethylolpropane, Triethanolamine, sorbitan monooleate, pentaerythritol, sorbitol, diglycerin, tripentaerythritol, etc.) and amino alcohols (triethanolamine, butyldiethanolamine, etc.) that do not have a hydrogen atom directly linked to the nitrogen atom, and one or more alkylene oxides. Is added.

The number of moles of alkylene oxide added in (b) is usually 1 to 1000 moles, preferably 10 to 200 moles.

As the alkylene oxide constituting (b), ethylene oxide and / or propylene oxide is preferable, and propylene oxide alone or a combination of ethylene oxide and propylene oxide is particularly preferable.

The weight ratio of (a) / (b) in the polyol component is usually 5/95 to 90/10, preferably 10/9.
It is 0 to 80/20.

As the polyol component, polyhydric alcohols (the above dihydric alcohols, trihydric or higher alcohols, polyamines, aminoalcohols, etc.) may be used in combination with (a) and (b), if necessary. . In this case, the amount of the polyhydric alcohol used is usually 50% by weight or less in the polyol component.

Examples of the carboxylic acids (c) in the present invention include monovalent to tetravalent carboxylic acids. For example, 1
Carboxylic acids (acetic acid, propionic acid, stearic acid,
Oleic acid, benzoic acid, methylbenzoic acid, cinnamic acid, and linseed oil fatty acid, castor oil fatty acid, coconut oil fatty acid,
Palm kernel oil fatty acids, safflower oil fatty acids, soybean oil fatty acids, tung oil fatty acids, rapeseed oil fatty acids, cottonseed oil fatty acids, tall oil fatty acids, dehydrated castor oil fatty acids and other natural fatty acid fatty acids; divalent carboxylic acids (oxalic acid, succinic acid) , Alkylsuccinic acid, adipic acid, sebacic acid, fumaric acid, maleic acid, phthalic acid, terephthalic acid, hymic acid, etc.);
Trivalent carboxylic acids (propanetricarboxylic acid, butanetricarboxylic acid, trimellitic acid, etc.); Tetravalent carboxylic acids (butanetetracarboxylic acid, pyromellitic acid, etc.); and ester forming properties of these mono- and tetravalent carboxylic acids Derivatives (anhydrides, acid halides, methyl esters, glycerides, etc.); and mixtures thereof.

Preferred as (c) are trivalent or tetravalent carboxylic acids and their ester-forming derivatives, and particularly preferred are trivalent or tetravalent aromatic carboxylic acids and their ester-forming derivatives.

The polyester (A) comprises a polyol component composed of one or more alkylene oxide adducts (a) of bisphenols having two or more active hydrogens and one or more alkylene oxide adducts (b) of polyhydric alcohols.
It can be obtained by the esterification reaction with a carboxylic acid (c) by a conventional method. After the reaction, if necessary, the catalyst component can be removed and the unreacted alcohol component can be removed.

The hydroxyl value of (A) is usually 10 to 500,
Preferably 30-300, more preferably 40-20
It is 0, and the acid value is usually 50 or less, preferably 20 or less, more preferably 10 or less.

The equivalent ratio of the carboxyl groups in (c) constituting the polyester (A) to the hydroxyl groups in the polyol component varies depending on the number of hydroxyl groups in each polyol and the number of carboxyl groups in (c), but is usually , 1: (1.5-
5), preferably 1: (2.5-3.5).

The printing ink (I) for metal of the present invention comprises polyester (A), amino resin (B), pigment and solvent as main components.

The amino resin (B) is not particularly limited, and guanamine resin (benzoguanamine resin and the like), melamine resin (trimethylol melamine, hexamethylol melamine and alkyl ethers thereof) and the like can be used. The pigment is not particularly limited, and ordinary inorganic and organic pigments can be used.

The solvent is not particularly limited, and in addition to ordinary ink solvents (saturated hydrocarbon, alkylbenzene, alkyl ether of glycols, diethyl phthalate, etc.), polyalkylene oxides and the like can be used.

The content of each component with respect to the total amount of printing ink is
Usually, polyester (A) is 10 to 70% by weight, preferably 10 to 10% by weight, amino resin (B) is 10 to 50% by weight, pigment is 5 to 60% by weight, and solvent is 10 to 30% by weight. is there.

The mixing method of each component is not particularly limited, and a conventional method using a triple roll, a ball mill or the like can be used.

As an example of the method for printing the printing ink for metal of the present invention, there is a method in which after dry offset curved surface printing, a finish varnish is roll-coated in a wet ink state and the ink is baked thereon.

The ink baking conditions are usually 130 ° C to 2 ° C.
At 30 ° C., the time ranges from 20 seconds to 20 minutes.

If necessary, a dryer, a curing agent, etc. can be used.

[0028]

EXAMPLES The present invention will be further described below with reference to examples, but the present invention is not limited thereto. Parts in the examples are parts by weight.

Production Example 1 Propylene oxide adduct of bisphenol A (molecular weight = 460) 920 parts (2 moles) and ethylene oxide / propylene oxide random adduct of trimethylolpropane (weight ratio 30/70, molecular weight = 700) 7
00 parts (1 mol) and 192 parts of trimellitic anhydride (1
To give a hydroxyl value of 17
A transparent viscous liquid resin (resin A-1) having an acid value of 3.7 was obtained.

Production Example 2 Ethylene oxide adduct of bisphenol A (molecular weight =
580) 1450 parts (2.5 mol) and propylene oxide adduct of glycerin (molecular weight = 1000) 500
Parts (0.5 mol) and 192 parts of trimellitic anhydride (1
To give a hydroxyl value of 94,
A transparent viscous liquid resin (resin A-2) having an acid value of 2.0 was obtained.

Production Example 3 Ethylene oxide / propylene oxide random adduct of bisphenol A (weight ratio 30/70, molecular weight = 10)
00) 1000 parts (1 mol), pentaerythritol propylene oxide adduct (molecular weight = 700) 700 parts (1 mol), neopentyl glycol 104 parts (1 mol) and trimethylolpropane 134 parts (1 mol).
Then, 218 parts (1 mol) of pyromellitic dianhydride was esterified by a conventional method to obtain a transparent viscous liquid resin (resin A-3) having a hydroxyl value of 125 and an acid value of 5.4.

Production Example 4 170 parts of neopentyl glycol, 110 parts of trimethylolpropane, 170 parts of adipic acid, and 200 parts of isophthalic acid were esterified by a conventional method using 1.9 parts of dibutyltin dilaurate as a catalyst to give a hydroxyl value of 91. A transparent viscous liquid resin having an acid value of 5.9 (Comparative Resin D-1) was obtained.

Examples 1 to 3 and Comparative Example 1 40 parts of each of Resins A-1 to 3 and D-1 were used, and
15 parts of diethylene glycol monobutyl ether, 40 parts of titanium oxide, and 15 parts of hexamethylol melamine (CYMEL 300 manufactured by Mitsui Toatsu Co., Ltd.) were added, and then each was made into an ink by using a three-roll mill, and inks A′-1 to A′-3.
(Examples 1 to 3) and D'-1 (Comparative example 1) were obtained.

Examples 4 to 12 and Comparative Example 2 Resin A-1 was prepared in the same manner as in Examples 1 to 3 and Comparative Example 1 except that alkylbenzene (Alken N56N manufactured by Nisseki Chemical Co., Ltd.) was used instead of diethylene glycol monobutyl ether. Ink A ″ -1 to A ″ -3 (Example 4)
6) and D ″ -1 (Comparative Example 2) were obtained.

Test Examples and Comparative Test Examples Using the inks obtained in Examples 1 to 6 and Comparative Examples 1 to 2, printing was performed on a 2-piece aluminum can by a dry offset method, and an aqueous acrylic resin (Mitsui Toatsu Alma Co., Ltd.) was used. Tex WA41)
After overprinting an aqueous overprint varnish consisting of 60 parts, 60 parts of deionized water, 15 parts of a water-soluble benzoguanamine resin (CYMEL 1123 manufactured by Mitsui Toatsu Co., Ltd.), and 10 parts of butyl cellosolve, baking was performed at 200 ° C. for 2 minutes, The paintability (repellency, gloss), coating film hardness, and evaluation were performed. The results are shown in Table 1.

[0036]

[Table 1]

(Note) Gloss and cissing: The coating film was visually inspected and indicated as ◯ when it was good, Δ when it was normal level, and × when it was unusable level. -Coating film hardness: According to the JIS standard, the pencil hardness of the coating film is shown.

[0038]

As described above, the printing ink for metal (I) of the present invention is wet-coated with an aqueous type overprint varnish in a wet state after printing the ink, as shown in the examples and the like. In the printing method for printing, varnish repellency on the ink coating surface and varnish penetration into the ink film do not occur for water-based overprint varnish, so it has sufficient suitability and excellent gloss and coating. It gives the film hardness.

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Claims (3)

[Claims] 1. A pigment, the metallic printing inks comprising a resin and a solvent as main components, as the resin component, alkylene oxide adducts of bisphenols (a) and aliphatic polyhydric alcohol alkylene oxide adduct (b)
A polyester component ( A ) obtained by reacting a polyol component consisting of (4) with a carboxylic acid ( c ) and an amino resin (B) are used, and the content of ( A ) is 10 to 70% by weight based on the total amount of the printing ink. A printing ink for metals ( I ), characterized in that Wherein (A) is, printing ink according to claim 1, wherein the polyester having a hydroxyl value of 30 to 300 (I). 3. The content of ( a ) in the polyol component is
The printing ink ( I ) according to claim 1 or 2, which is 10 to 90% by weight.