JP2016079306A - Surface printing overprint varnish composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: a surface printing overprint varnish composition for obtaining a gravure printed matter that has an excellent high-speed printability, PVC anti-blocking property, and gloss; a printing method; and a printed matter.SOLUTION: Provided is a surface printing overprint varnish composition characterized in containing a polyamide resin, a cellulose derivative, a chelating crosslinking agent and an organic solvent.SELECTED DRAWING: None

Description

  The present invention relates to an overprint varnish composition for surface printing, a gravure printing method, and a gravure print for obtaining a gravure print excellent in high-speed printability, vinyl chloride blocking resistance and gloss.

For packaging of products such as bread, rice balls, and confectionery, a simple configuration (front surface gravure printing ink is printed on the front side of the resin film for decoration and surface protection, and not printed on the back side that comes into contact with food (front surface). Printed material called “print printing method” is used.
Since such surface printing gravure printing ink is printed on the front side of the resin film, the ink film is directly exposed to the outside, and tough film properties are required.
Also, from food manufacturers and converters, etc., adhesion to resin film, heat resistance (performance to prevent the ink film from adhering to the hot plate at the part where the heat plate of the heat seal hits when making a resin film), oil resistance Property (performance to prevent the oil contained in food from touching the printed surface even if it touches it), blocking resistance (because the printed surfaces or the printed surface and the back of the film do not adhere even if they are in close contact with each other) Performance), vinyl chloride blocking resistance (performance when the printed surface does not adhere to the soft vinyl chloride sheet used for tablecloths, etc.), stretchability (when the bag is opened) There is a demand for performance that the printed surface printed on the film can follow even if it extends.

In order to ensure these tough ink film properties, a gravure printing ink composition for surface printing using a polyurethane resin and a cellulose derivative as a binder resin (see, for example, Patent Document 1 and Patent Document 2), polyamide resin and cellulose A gravure ink composition for surface printing using a derivative (for example, Patent Documents 3 and 4), and a gravure ink for surface printing using a polyurethane resin and a vinyl chloride / vinyl acetate copolymer in combination have been proposed (for example, , Patent Document 5 and Patent Document 6).
In recent years, surface printing gravure inks having higher performance that have high-speed printing suitability and excellent vinyl chloride blocking suitability have been demanded by surface printing ink users. For high-speed printing aptitude, it is advantageous to use polyurethane resin as a binder for gravure ink for surface printing. However, depending on the type of PVC cloth used for table cloth, etc., it is improved for PVC blocking resistance. There was room for.

JP 2007-246822 A JP 2002-294128 A JP2012-107131A Japanese Patent Laid-Open No. 10-069759 JP 2012-012597 A JP2013-256551A

  The object of the present invention is to obtain a gravure printed material that is excellent in high-speed printing suitability, varnish adhesion, blocking resistance, polyvinyl chloride blocking resistance, and gloss, and also excellent in heat resistance and oil resistance to aluminum and the printed surface. The object is to provide an overprint varnish composition for surface printing, a gravure printing method, and a gravure print.

  As a result of intensive studies to solve the above-mentioned problems, the inventors of the present invention contain a polyamide resin, a cellulose derivative, a chelate crosslinking agent and an organic solvent after printing a gravure solvent type urethane printing ink composition on a resin film. By applying the overprint varnish composition for surface printing, it was found that a gravure print excellent in high-speed printing suitability, vinyl chloride blocking resistance and gloss was obtained, and the present invention described below was completed.

That is, the present invention
1. An overprint varnish composition for surface printing, comprising a polyamide resin, a cellulose derivative, a chelate crosslinking agent, and an organic solvent.
2. 2. The overprint varnish composition for surface printing according to 1, wherein the organic solvent is a non-aromatic organic solvent.
3. A gravure printing method, comprising: printing a solvent-type urethane-based printing ink composition on a resin film, and then applying the overprint varnish composition for surface printing described in 1 or 2 above.
4). The solvent type urethane printing ink composition is a solvent type urethane printing ink composition containing an organic pigment, a binder resin, and an organic solvent, and the binder resin is obtained by reacting a diol compound and an organic diisocyanate compound. Polyurethane resin, or the polyurethane resin and (cellulose derivative and / or vinyl chloride / vinyl acetate copolymer), and the solid content mass ratio of polyurethane resin and (cellulose derivative + vinyl chloride / vinyl acetate copolymer) is polyurethane. Resin: (cellulose derivative + vinyl chloride / vinyl acetate copolymer) = 95: 5 to 5:95 The gravure printing method according to 3,
5.3 Surface printed matter obtained by using the gravure printing method described in 3 or 4.

  According to the overprint varnish composition for surface printing of the present invention, it is excellent in high-speed printing suitability, varnish adhesion, blocking resistance, vinyl chloride blocking resistance, and gloss, and further in heat resistance and oil resistance to aluminum and the printed surface. Excellent film can be obtained.

Hereinafter, the overprint varnish composition for surface printing, the printing method, and the printed matter of the present invention will be described.
[Overprint varnish composition for surface printing]
The overprint varnish composition for surface printing according to the present invention will be described.
As the overprint varnish composition for surface printing, a composition containing a polyamide resin, a cellulose derivative, a chelate crosslinking agent and an organic solvent can be used.

(Polyamide resin)
The polyamide resin mainly includes a polymerized fatty acid, an acid component which may partially contain aliphatic, alicyclic and aromatic dicarboxylic acids and aliphatic monocarboxylic acids, and mainly aliphatic, alicyclic, aromatic It is obtained by reacting an aliphatic or aromatic polyamine alone or as a mixture with an amine component which may partially contain a primary and secondary monoamine.
Here, the polymerized fatty acid is generally obtained by polymerization of an unsaturated fatty acid having 16 to 22 carbon atoms or an ester thereof, and includes a monobasic fatty acid, a dimerized polymerized fatty acid, a trimerized polymerized fatty acid and the like. Examples of the aliphatic dicarboxylic acid include succinic acid, adipic acid, azelaic acid, and maleic acid. Examples of the alicyclic dicarboxylic acid include cyclohexane dicarboxylic acid. Examples of the aromatic dicarboxylic acid include isophthalic acid and terephthalic acid. be able to. Furthermore, examples of the aliphatic monocarboxylic acid include acetic acid, stearic acid, oleic acid, and linoleic acid.

  On the other hand, examples of the aliphatic polyamine in the amine component include aliphatic diamines such as ethylenediamine, propylenediamine, hexamethylenediamine, and methylaminopropylamine, and aliphatic polyamines such as diethylenetriamine and triethylenetetramine. Examples of group polyamines include cyclohexylenediamine and isophoronediamine. Examples of araliphatic polyamines include xylylenediamine, and examples of aromatic polyamines include phenylenediamine and diaminodiphenylmethane. Further, examples of primary and secondary monoamines include butylamine, octylamine, diethylamine, monoethanolamine, monopropanolamine, diethanolamine, dipropanolamine and the like.

From the viewpoint of oil resistance, heat resistance, and vinyl chloride blocking resistance of the overprint varnish composition for surface printing of the present invention, among polyamide resins, a polyamide resin having a hydroxyl group in the molecule using alkanolamine as a primary or secondary monoamine component Is preferably used.
As a method of synthesizing a polyamide resin from the above acid component and amine component, the ratio of carboxyl group / amino group of the reaction component is 0.9 / 1.0 to 1.0 / 0.9, preferably 1.0 / The reaction temperature is set to 1.0, the reaction temperature is set to 160 to 280 ° C, preferably 180 to 230 ° C, and the reaction is desirably performed under a reduced pressure of about 100 torr in the final stage.

(Cellulose derivative)
Examples of the cellulose derivative include nitrocellulose as a nitro group-substituted product, cellulose acetate and cellulose acetate propionate as a lower acyl group-substituted product, and methyl cellulose and ethyl cellulose as lower alkyl group-substituted products.
As for the molecular weight of these cellulose derivatives and the degree of substitution with each substituent, those within the range used in ordinary paints and ink compositions can be used without any problem in the present invention. Is preferably about 30 to 85%. From the viewpoint of heat resistance, the use of nitrocellulose having a nitro group-substituted product is advantageous.
The amount of polyamide resin and cellulose derivative used in the overprint varnish composition for surface printing of the present invention is such that the solid content mass ratio of polyamide resin and cellulose derivative is polyamide resin: cellulose derivative = 95: 5-50: 50, preferably 90:10 to 70:30. When the solid content mass ratio of the polyamide resin exceeds 95, the heat resistance tends to decrease, and when it is less than 50, the vinyl chloride blocking resistance tends to decrease.

(Chelate crosslinking agent)
As the chelate crosslinking agent, titanium chelate, zirconium chelate, or the like can be used as the metal chelate crosslinking agent.
Titanium chelates such as tetraisopropyl titanate, tetranormal butyl titanate, butyl titanate dimer, tetra (2-ethylhexyl) titanate, tetramethyl titanate, tetrastearyl titanate, triethanolamine titanate, titanium acetyl acetate, titanium ethyl acetoacetate Examples thereof include titanium chelates such as acetate, titanium lactate, octylene glycol titanate, titanium tetraacetylacetonate, n-butyl phosphate titanium, and propanedioxtitanium bis (ethylacetylacetate).
Examples of the zirconium chelate include zirconium propionate and zirconium acetyl acetate.
From the viewpoint of the environment, among chelate crosslinking agents, chelate crosslinking agents that do not generate acetylacetone after the crosslinking reaction are preferable.
The content of the chelate crosslinking agent is preferably 0.1 to 8.0% by mass in the overprint varnish composition for surface printing, and more preferably 1.0 to 3.0% by mass. When the content is less than 0.1% by mass, the heat resistance, oil resistance, and vinyl chloride blocking resistance tend to decrease. When the content exceeds 8.0% by mass, the temporal stability of the overprint varnish composition for surface printing Tends to decrease.

(Organic solvent)
The organic solvent is preferably an organic solvent that does not contain an aromatic hydrocarbon organic solvent in consideration of the environment. Examples of organic solvents that do not contain aromatic hydrocarbon organic solvents include alcohol organic solvents such as methanol, ethanol, n-propanol, isopropanol, and butanol, ketone organic solvents such as acetone, methyl ethyl ketone, and methyl isobutyl ketone, Esters organic solvents such as methyl acetate, ethyl acetate, propyl acetate, butyl acetate, aliphatic hydrocarbon organic solvents such as n-hexane, n-heptane, n-octane, and cyclohexane, methylcyclohexane, ethylcyclohexane, cyclohexane Examples thereof include alicyclic hydrocarbon-based organic solvents such as heptane and cyclooctane, which can be mixed and used in consideration of the solubility and drying property of the binder resin. However, in consideration of the environment, it is preferable to suppress the ketone organic solvent as much as possible among the above organic solvents.
The amount of these organic solvents used is 75% by mass or more in the overprint varnish composition for surface printing of the present invention in consideration of printability.

(Coloring material)
In general, the overprint varnish composition for surface printing of the present invention does not contain a colorant. However, very slight coloration can also be included. Colorants that can be used in this case are inorganic, organic or extender pigments that can be used in printing ink compositions generally containing an organic solvent.
For example, usable inorganic pigments include titanium oxide, bengara, antimony red, cadmium red, cadmium yellow, cobalt blue, bitumen, ultramarine, carbon black, graphite, and the like, and organic pigments include soluble azo pigments and insoluble azo pigments. Examples thereof include pigments, azo lake pigments, condensed azo pigments, copper phthalocyanine pigments, and condensed polycyclic pigments. Further usable extender pigments include calcium carbonate, kaolin clay, barium sulfate, aluminum hydroxide, talc and the like. As content of these pigments, 0.5-1.0 mass% is a suitable quantity in the overprint varnish composition for surface printing of this invention as needed.
Further, as a coloring material, a dye for ordinary printing ink can be used.

(Additives that can be added as needed)
Furthermore, the overprint varnish composition for surface printing of the present invention includes a fatty acid amide, a hard resin (dimer acid resin, maleic acid resin) as long as the performance of the overprint varnish composition for surface printing of the present invention does not deteriorate. Petroleum resins, terpene resins, ketone resins, dammar resins, copal resins, chlorinated polypropylene, polypropylene oxide, etc.), leveling agents, surfactants, polyolefin waxes, paraffin waxes, and other known waxes can be added.

[Solvent type urethane printing ink composition]
As the solvent-based urethane printing ink composition used in the printing method of the present invention, those conventionally used in solvent-based printing ink compositions for gravure containing a polyurethane resin as a binder resin can be used.
For example, a gravure solvent type urethane printing ink composition containing a pigment, a binder resin, a chelate crosslinking agent, a hard resin, a fatty acid amide, and an organic solvent may be mentioned.

(Binder resin)
The binder resin contains a polyurethane resin or the polyurethane resin and (cellulose derivative and / or vinyl chloride / vinyl acetate copolymer).
Among them, a combined system of a polyurethane resin and a cellulose derivative (a polyurethane resin and a cellulose derivative can be used in a mass ratio of polyurethane resin: cellulose derivative = 5: 95 to 95: 5, and more preferably a polyurethane resin. : Cellulose derivative = preferably used in a mass ratio of 50:50 to 70:30) or a combined system of polyurethane resin and vinyl chloride / vinyl acetate copolymer (polyurethane resin and vinyl chloride / vinyl acetate copolymer) The polymer can be used in combination with polyurethane resin: vinyl chloride / vinyl acetate copolymer = 95: 5 to 5:95, and more preferably polyurethane resin: vinyl chloride / vinyl acetate copolymer = 90: Use in a mass ratio of 10 to 50:50, particularly preferably in the range of 80:30 to 60:40 It is preferred), and the like.
From the viewpoint of high-speed printability, the binder resin is preferably a combined system of a polyurethane resin and a cellulose derivative, or a combined system of a polyurethane resin and a vinyl chloride / vinyl acetate copolymer, and the resin film is yellowed by an antioxidant. Is preferably a combined system of polyurethane resin and vinyl chloride / vinyl acetate copolymer.
The content of the binder resin in the solvent-based urethane printing ink composition in the present invention is appropriately 2.0 to 20% by mass, more preferably 2.0 to 15% by mass.

(Polyurethane resin)
The polyurethane resins used as the binder resin are those conventionally used in printing ink compositions, especially gravure printing ink compositions, specifically diisocyanate compounds, diol compounds, and optionally chain extension. It is obtained by reacting an agent, a reaction terminator and the like.
Here, usable diisocyanate compounds include aliphatic diisocyanate compounds such as hexamethylene diisocyanate and 2,2,4-trimethylhexamethylene diisocyanate, isophorone diisocyanate, hydrogenated xylylene diisocyanate, and 4,4-cyclohexylmethane diisocyanate. Examples thereof include alicyclic diisocyanate compounds, xylylene diisocyanate, aromatic aliphatic diisocyanate compounds such as α, α, α ′, α′-tetramethylxylylene diisocyanate, and aromatic diisocyanate compounds such as toluylene diisocyanate and diphenylmethane diisocyanate. .

Next, as a suitable thing of the diol compound which can be utilized, a number average molecular weight is larger than 500 and 3000 or less, More preferably, it is a thing of 500-2000, and may consist of 1 type of diol compounds. In addition, a plurality of diol compounds may be used in combination. When the number average molecular weight of the diol compound is 500 or less, the adhesiveness tends to decrease. On the other hand, when the number average molecular weight exceeds 3000, the oil resistance tends to decrease.
Specific examples of the diol compound include alkylene glycol compounds having a molecular weight of 100 or more, polyalkylene glycol compounds such as polyethylene glycol and polypropylene glycol, and diol compounds such as low molecular weight alkylene glycol and bisphenol, and oxyalkylenes such as ethylene oxide and propylene oxide. And polyether diol compounds obtained by polyaddition of benzene and tetrahydrofuran.
Also, linear glycols such as ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, 1,2-propanediol, neopentyl glycol, 3-methyl-1, Low molecular diol compounds such as branched glycols such as 5-pentanediol, 2,4-diethyl-1,5-pentanediol, and ethylbutylpropanediol; and ether-based diols such as diethylene glycol and triethylene glycol; and succinic acid, Polyester diol compounds, lactones, etc. obtained by polycondensation of dicarboxylic acid compounds such as saturated and unsaturated aliphatic dicarboxylic acids such as adipic acid, azelaic acid, sebacic acid and maleic acid, and aromatic dicarboxylic acids such as phthalic acid Polyester obtained by ring-opening reaction of cyclic ester compound It can be exemplified Rujioru compound.
Furthermore, a polycarbonate compound having a straight chain or a side chain, a polybutadiene glycol compound, and the like can be used in combination.
In order to obtain good printability in a system that does not contain aromatic hydrocarbon organic solvents (toluene, etc.) in consideration of the environment, and has a high content of highly polar organic solvents such as alcohols and esters. It is preferable to use a polyether diol compound as the polyol compound.
When using other solvents, it may be preferable to use a polyester diol compound.

Furthermore, in the present invention, it is also possible to use a polyurethane resin obtained by using a chain extender or a reaction terminator. Examples of the chain extender include ethylene glycol, propylene glycol, butylene glycol, diethylene glycol, triethylene glycol, and the like. And aliphatic diamines such as ethylenediamine, 1,4-butanediamine, isophoronediamine, and aminoethylethanolamine.
Examples of the reaction terminator include monoalcohols such as methanol and ethanol, alkylamines such as n-propylamine, n-butylamine and di-n-butylamine, alkanolamines such as monoethanolamine and diethanolamine, ethylenediamine, Examples include aliphatic diamines such as 4-butanediamine, isophoronediamine, and aminoethylethanolamine.

In order to obtain a polyurethane resin that is a binder resin used in the solvent-based urethane printing ink composition of the present invention using the above synthetic components, first, a molar equivalent ratio of NCO of an organic diisocyanate compound and OH of a diol compound (Mole equivalent of NCO of organic diisocyanate compound / mole equivalent of OH of diol compound) = 0.5 or more and 3 or less, preferably 1.2 or more and 1.5 or less, and then, if necessary, chain It can be obtained by reacting an extender and a reaction terminator.
In addition, when the molar equivalent of NCO of the organic diisocyanate compound / the molar equivalent of OH of the diol compound is less than 0.5, the heat resistance and oil resistance tend to decrease, whereas the molar equivalent of NCO of the organic diisocyanate compound / When the molar equivalent of OH of the diol compound exceeds 3, the stretchability tends to decrease.
The polyurethane resin having a hydroxyl group is preferable among the polyurethane resins from the viewpoints of adhesion to the resin film of the solvent-type urethane printing ink composition in the present invention, blocking resistance, oil resistance, and heat resistance, and in particular, as a chain extender. It is preferable to use a diamino alcohol compound such as glycerin or aminoethylethanolamine and introduce a hydroxyl group into the molecule of the polyurethane resin.

  As a method for obtaining a polyurethane resin having such a hydroxyl group, (1) a method in which an organic diisocyanate compound is reacted at a molar ratio of less than 1.0 times that of a polyol compound without using a chain extender or a reaction terminator; 2) After reacting an organic diisocyanate compound and a polyol compound to synthesize a urethane prepolymer, the chain extender is a diamino alcohol compound such as glycerin or aminoethylethanolamine, and the reaction terminator is an alkanol such as monoethanolamine or diethanolamine. Any known method such as a method of introducing a hydroxyl group by reacting an amine compound can be used.

(Vinyl chloride / vinyl acetate copolymer)
As the vinyl chloride / vinyl acetate copolymer, a copolymer of a vinyl chloride monomer and a vinyl acetate monomer, which has been conventionally used in printing ink compositions for surface printing, can be used.
Among these, vinyl chloride / vinyl acetate copolymers having a hydroxyl group are more preferable from the viewpoint that it is advantageous to improve various performances related to the problems of the present invention in an organic solvent system of an environment-friendly ink. It is. Such a vinyl chloride / vinyl acetate copolymer having a hydroxyl group can be obtained by saponifying a part of the acetate portion.
In the case of a vinyl chloride / vinyl acetate copolymer having a hydroxyl group obtained by saponifying a part of the acetate portion, a structural unit based on the reaction site of vinyl chloride in the molecule (the following formula 1), vinyl acetate The film physical properties and dissolution behavior of the resin are determined by the ratio of the structural unit based on the reaction site (formula 2 below) and the structural unit based on the saponification of the vinyl acetate reaction site (formula 3 below).
That is, the structural unit based on the reaction site of vinyl chloride gives the toughness and hardness of the resin film, and the structural unit based on the reaction site of vinyl acetate provides adhesion and flexibility, and saponifies the reaction site of vinyl acetate. The structural unit based on imparts good solubility of environmentally friendly inks in organic solvents.
Formula 1 -CH2-CHCl-
Formula 2 -CH2-CH (OCOCH3)-
Formula 3 -CH2-CH (OH)-

(Cellulose derivative)
As a cellulose derivative, the cellulose derivative conventionally used for the printing ink composition for surface printing can be used. Examples of cellulose derivatives include lower acyl group-substituted products such as nitrocellulose (nitro group-substituted products), cellulose acetate, cellulose acetate propionate, and cellulose acetate butyrate, and lower alkyl group-substituted products such as methyl cellulose and ethyl cellulose. . As for the molecular weight of these cellulose derivatives and the degree of substitution with respect to hydroxyl groups, those in the range used in ordinary ink compositions and paints can be used without any problem in the present invention, and the degree of substitution of hydroxyl groups is generally 1.3-2. About 7 is preferable. Also, the use of a nitro group-substituted product is advantageous from the viewpoint of heat resistance, and the lower acyl group-substituted product and lower alkyl group-substituted product are advantageous from the viewpoint of adhesiveness. It is preferable to use it.

(Coloring material)
The coloring material that can be used as needed in the solvent-based urethane printing ink composition in the present invention is generally an inorganic, organic, or extender pigment that can be used in a printing ink composition containing an organic solvent.
For example, usable inorganic pigments include titanium oxide, bengara, antimony red, cadmium red, cadmium yellow, cobalt blue, bitumen, ultramarine, carbon black, graphite, and the like, and organic pigments include soluble azo pigments and insoluble azo pigments. Examples thereof include pigments, azo lake pigments, condensed azo pigments, copper phthalocyanine pigments, and condensed polycyclic pigments. Further usable extender pigments include calcium carbonate, kaolin clay, barium sulfate, aluminum hydroxide, talc and the like. As content of these pigments, 0.5-50 mass% is a suitable quantity in a solvent-type urethane type printing ink composition.
Moreover, the dye for a normal printing ink can be used also as a dye as a coloring material.

(Chelate crosslinking agent)
A chelate crosslinking agent can also be mix | blended with a solvent type urethane type printing ink composition. As such a metal chelate cross-linking agent, titanium chelate, zirconium chelate and the like can be used.
Typical examples of titanium chelates include tetraisopropyl titanate, tetranormal butyl titanate, butyl titanate dimer, titanium alkoxide such as tetra (2-ethylhexyl) titanate, tetramethyl titanate, tetrastearyl titanate, triethanolamine titanate, titanium acetyl acetate, Mention may be made of titanium chelates such as titanium ethyl acetoacetate, titanium lactate, octylene glycol titanate, titanium tetraacetylacetonate, n-butyl phosphate titanium, propanedioxitanium bis (ethylacetylacetate).
Examples of the zirconium chelate include zirconium propionate and zirconium acetyl acetate.
From an environmental point of view. Among chelate crosslinking agents, chelate crosslinking agents that do not generate acetylacetone after the crosslinking reaction are preferred.
The content of the chelate crosslinking agent is preferably 0.1 to 8.0% by mass, more preferably 1.0 to 2.0% by mass in the solvent-type urethane printing ink composition. When the content is less than 0.1% by mass, the heat resistance, oil resistance, and vinyl chloride blocking resistance tend to decrease. When the content exceeds 8.0% by mass, the aging stability of the varnish tends to decrease.

(Fatty acid amide)
Examples of fatty acid amides include saturated fatty acid amides, unsaturated fatty acid amides, and modified fatty acid amides, and it is preferable to use modified fatty acid amides from the viewpoint of blocking resistance to a soft vinyl chloride sheet used for table cloth.
The content of the fatty acid amide is preferably 0.1 to 3.0% by mass, more preferably 0.5 to 2.0% by mass in the solvent-type urethane printing ink composition.
If the content of the fatty acid amide is less than 0.1% by mass, the blocking resistance and adhesion may be reduced. If it exceeds 3.0% by mass, the vinyl chloride blocking resistance may be reduced. .

(Hard resin)
Examples of the hard resin include dimer acid resin, rosin resin, maleic acid resin, petroleum resin, terpene resin, ketone resin, dammar resin, copal resin, chlorinated polypropylene, and polypropylene oxide. When these hard resins are used, an improvement in adhesiveness can be expected particularly for a resin film that has not been surface-treated. And as for content of the hard resin in the solvent type urethane type printing ink composition in this invention, 0.1-5.0 mass% is a suitable quantity.

(Organic solvent)
The organic solvent is preferably an organic solvent that does not contain an aromatic hydrocarbon organic solvent in consideration of the environment.
Examples of organic solvents that do not contain aromatic hydrocarbon organic solvents include alcohol organic solvents such as methanol, ethanol, n-propanol, isopropanol, and butanol, ketone organic solvents such as acetone, methyl ethyl ketone, and methyl isobutyl ketone, Esters organic solvents such as methyl acetate, ethyl acetate, propyl acetate, butyl acetate, aliphatic hydrocarbon organic solvents such as n-hexane, n-heptane, n-octane, and cyclohexane, methylcyclohexane, ethylcyclohexane, cyclohexane Examples thereof include alicyclic hydrocarbon-based organic solvents such as heptane and cyclooctane, which can be mixed and used in consideration of the solubility and drying property of the binder resin. However, in consideration of the environment, it is preferable to suppress the ketone organic solvent as much as possible among the above organic solvents.
The amount of these organic solvents used is 15.0% by mass or more in the overprint varnish composition for surface printing in the present invention in consideration of printability. From the viewpoint of printability, it is preferable that propyl acetate is contained in the overprint varnish composition for surface printing in an amount of 5.0% by mass or more, more preferably 10.0% by mass or more.

(Additives that can be added as needed)
Furthermore, a wax can be added to the solvent-based urethane printing ink composition in the present invention within the range where the performance of the solvent-based urethane printing ink composition does not deteriorate for the purpose of improving the friction resistance.
Various known waxes such as polyolefin wax and paraffin wax can be used as the wax.
Furthermore, various ink additives such as a pigment dispersant, a leveling agent, a surfactant, and a plasticizer can be arbitrarily added to the solvent-based urethane printing ink composition in the present invention.

[Method for Producing Solvent Type Urethane Printing Ink Composition in the Present Invention]
As a method for producing a solvent-based urethane printing ink composition in the present invention using these materials, first, a pigment, a binder resin, an organic solvent, and, if necessary, a pigment dispersant, a surfactant and the like are stirred. After mixing, kneading using various milling machines such as bead mill, ball mill, sand mill, attritor, roll mill, pearl mill, etc., and further adding and mixing fatty acid amide, chelate cross-linking agent, hard resin and remaining materials Is adopted.

[Printing method]
Next, the gravure printing method of the present invention will be described.
As the gravure printing method of the present invention, for example, first, a gravure solvent type urethane printing white ink composition is printed on a resin film by a gravure printing method with a coating amount of a dry film 0 to 2.0 g / m ^2. To dry. Next, the gravure solvent type urethane printing color ink composition is printed on the previously printed white ink film layer by a gravure printing method with a coating amount of 0 to 2.0 g / m ² of the dry film. It can be obtained by drying with a dryer.
Finally, the overprint varnish composition for surface printing is applied by a gravure printing method or the like so that the dry film covers the ink film layer with an application amount of 0 to 2.0 g / m ² and is then dried by a dryer. it can.

(Resin film)
Examples of the resin film to be printed in the gravure printing method of the present invention include stretched and unstretched polyolefin such as polyethylene and polypropylene, polyester, nylon, cellophane, vinylon, and the like.

[Printed surface]
The printed surface print obtained by the above gravure printing method is made into a bag and used for packaging containers such as food.

Although an Example and a comparative example are shown, this invention is not limited only to these Examples. Unless otherwise specified, “%” means “% by mass”, and “part” means “part by mass”.
[Overprint varnish composition for surface printing]
<Polyamide resin solution>
30 parts of a polyamide resin (Rheamide S2600, manufactured by Kao Corporation) was dissolved in a mixed solvent of 50 parts of methylcyclohexane and 20 parts of isopropyl alcohol to obtain a polyamide resin solution having a solid content of 30%.
<Nitrocellulose solution>
20 parts of nitrocellulose (NC RS-2 KCNC, manufactured by KOREA CNC LTD) was dissolved in a mixed solvent consisting of 35 parts of propyl acetate and 45 parts of isopropyl alcohol to obtain a nitrocellulose solution having a solid content of 20%.
<Metal chelate crosslinking agent>
Titanium acetyl acetate <Preparation of overprint varnish composition for surface printing>
The materials shown in Table 1 below were kneaded with a paint conditioner to prepare a gravure solvent type printing ink composition for surface printing. In addition, the numerical value described in Table 1 is mass%.

[Solvent type urethane printing ink composition]
<Polyurethane resin varnish>
A four-necked flask equipped with a stirrer, a cooling pipe and a nitrogen gas introduction pipe was charged with 400 g of polyethylene glycol having a number average molecular weight of 1,000, 115.4 g of isophorone diisocyanate and 0.1 g of tetrabutyl titanate, and nitrogen gas was introduced. The reaction was carried out at 100 ° C. for 4 hours. After adding 375 g of ethyl acetate, 500 g of propyl acetate, and 375 g of isopropyl alcohol, 20.7 g of isophoronediamine was added and reacted for 20 minutes. Further, 1.4 g of butylamine was added to stop the reaction, and polyurethane resin varnish (solid content 30%) )

<Vinyl chloride / vinyl acetate copolymer solution>
In a mixed organic solvent comprising 20 parts of a vinyl chloride / vinyl acetate copolymer (trade name: Solvain TA5R, manufactured by Nissin Chemical Co., Ltd.), 40 parts of methyl ethyl ketone, 20 parts of ethyl acetate, and 20 parts of propyl acetate. To obtain a vinyl chloride / vinyl acetate copolymer solution having a solid content of 20%.

<Nitrocellulose solution>
20 parts of nitrocellulose (NC RS-2 KCNC, manufactured by KOREA CNC LTD) was dissolved in a mixed solvent consisting of 35 parts of propyl acetate and 45 parts of isopropyl alcohol to obtain a nitrocellulose solution having a solid content of 20%.

<Fatty acid amide>
Lauric acid amide <hard resin>
Hard Resin Marquide No. 2 (Arakawa Chemical Industries, Ltd.)
<Metal chelate crosslinking agent>
Titanium acetyl acetate

Preparation of Solvent Type Urethane Printing Ink Composition The materials shown in Table 2 were kneaded with a paint conditioner to prepare a solvent type urethane printing ink composition. In addition, the numerical value described in Table 2 is mass%.

<Manufacture of surface-printed gravure prints>
A stretched polypropylene film (trade name: OPP P-2161, 25μ, manufactured by Toyobo Co., Ltd.) subjected to corona discharge treatment is applied to a solvent-type urethane-based white printing ink composition (1 or 3 in Table 2 above) using the gravure proofing machine. ) Was printed and dried under the following conditions, and then the solvent-based urethane-based color printing ink composition (2 or 4 in Table 2 above) was printed and dried under the following conditions.
Thereafter, the overprint varnish composition for surface printing was further applied and dried under the following conditions to obtain a surface printed gravure printed material.

(Solvent-type urethane-based white printing ink composition and solvent-type urethane-based color printing ink composition coating method and conditions)
Coating machine: Gravure proofing machine
Coating speed: 100m / min
Printing plate: Direct 175 line solid plate Drying temperature: 100 ° C (Air volume 80%)
The printing area of the solvent-based urethane-based white ink composition is 30% of the solvent-based color printing ink composition.

(Coating method and conditions for overprint varnish composition for surface printing)
Coating machine: Gravure proofing machine
Coating speed: 100m / min
Printing plate: Direct 175 line solid plate Drying temperature: 100 ° C (Air volume 80%)

Evaluation test (adhesiveness)
The cellophane tape was affixed to each printing surface of Examples 1-4 and Comparative Examples 1-2, and adhesiveness was evaluated from the degree to which the printed film peeled off from the film when it was rapidly peeled off.
A: As an area ratio of the printed film, peeling from the film is less than 5% B: As an area ratio of the printed film, 5% or more and less than 30 peel from the film C: As an area ratio of the printed film, 30% or more Peels from the film

(Blocking resistance)
The printed surface and the non-printed surface of Examples 1 to 4 and Comparative Examples 1 and 2 were combined, stuffed with a vise, and peeled by hand after 1 day at 40 ° C., which was resistant to the degree of ink peeling and the strength of peeling resistance. The blocking property was evaluated.
A: There is no peeling of the printed film B: The printed film is peeled off a little and the peel resistance is felt strongly C: The printed film is almost peeled off and the peel resistance is felt strongly

(PVC blocking resistance)
The soft vinyl chloride sheet cut into the same size as each printed matter of Examples 1 to 4 and Comparative Examples 1 and 2 and the printing surface were overlapped, a load of 0.5 kg / cm ² was applied, and 50 ° C. and 80%. After leaving for 24 hours in an atmosphere, the printed surface and the vinyl chloride sheet were peeled off, and the vinyl chloride blocking resistance was evaluated from the degree of ink peeling.
A: The printed film was not peeled at all B: The area where the film was peeled off from the film was more than 0% and 20% or less C: The area where the printed film was peeled from the film was more than 20 and less than 50% D : The area where the printed film peeled from the film exceeded 50%

(Heat-resistant)
Using a heat seal tester equipped with a hot plate having a thermal gradient of 80 to 200 ° C. on each printed surface of Examples 1 to 4 and Comparative Examples 1 to 2, the printed surface and the aluminum foil were 2.0 kg / cm. Pressed at a pressure of ² for 1 second.
<1. Evaluation of heat resistance from the lowest temperature at which the ink on the printed surface is transferred to the aluminum foil>
A: The thing of 160 degreeC or more B: The thing of 140 degreeC or more and less than 160 degreeC C: The thing of less than 140 degreeC

(Oil resistance)
The printed surface of each of the printed materials of Examples 1 to 4 and Comparative Examples 1 and 2 was rubbed 100 times under a load of 200 g with a cloth soaked with salad oil using a Gakushin type anti-friction tester. From this, the oil resistance was evaluated.
Evaluation criteria A: No change in printed surface B: Printed surface has streak scratches C: Printed surface has surface scratches

According to the present invention, it is possible to obtain a film having excellent varnish adhesion, blocking resistance and polyvinyl chloride blocking resistance, and also excellent heat resistance and oil resistance.
However, according to Comparative Examples 1 and 2 which were not overcoated with the overprint varnish composition for surface printing, the vinyl chloride blocking resistance of the twisted film was deteriorated, and the area where the printed film was peeled off from the film was 0. It exceeded the% and became the range of 20% or less.

Claims (5)

  An overprint varnish composition for surface printing, comprising a polyamide resin, a cellulose derivative, a chelate crosslinking agent, and an organic solvent.   The overprint varnish composition for surface printing according to claim 1, wherein the organic solvent is a non-aromatic organic solvent.   A gravure printing method comprising applying a surface-printing overprint varnish composition according to claim 1 or 2 to a resin film after printing a solvent-based urethane printing ink composition.   The solvent type urethane printing ink composition is a solvent type urethane printing ink composition containing an organic pigment, a binder resin, and an organic solvent, and the binder resin is obtained by reacting a diol compound and an organic diisocyanate compound. Polyurethane resin, or the polyurethane resin and (cellulose derivative and / or vinyl chloride / vinyl acetate copolymer), and the solid content mass ratio of polyurethane resin and (cellulose derivative + vinyl chloride / vinyl acetate copolymer) is polyurethane. Resin: (cellulose derivative + vinyl chloride / vinyl acetate copolymer) = 95: 5 to 5:95 The gravure printing method according to claim 3,   A surface printed matter obtained by using the gravure printing method according to claim 3 or 4.