JP5962238B2 - Gravure ink composition for surface printing - Google Patents

Description

  The present invention relates to a gravure ink composition for surface printing. More specifically, the ink can be stored for a long period of time, and the discoloration of the antioxidant contained in the film can be reduced when stored under a long period of high temperature and high humidity. Gravure printing ink for surface printing with excellent vinyl chloride blocking resistance, heat resistance, and follow-up properties and excellent environmental sanitation, especially excellent blocking resistance. It relates to a composition.

  In recent years, product packages are generally printed for decoration and surface protection. In addition, the consumer's willingness to purchase depends on the quality of the printed matter, such as the design, makeup, and luxury.

  On the other hand, with the diversification of packaging and advancement of packaging technology, food manufacturers and converters are demanding high quality and performance for printing inks.

  Furthermore, in the field of surface printing on plastic film, the performance of surface printing ink printed on the outer surface of the package includes not only the quality of printing, but also the adhesion to the film substrate, printing and winding. Blocking resistance to prevent the ink from adhering to the back surface of the film substrate, blocking resistance to prevent the printed materials from adhering to each other, and resistance to preventing the printed material from adhering to the soft vinyl chloride sheet used for table cloths. Various resistances are required, such as polyvinyl chloride blocking properties, friction resistance to prevent the printed surface from being damaged, oil resistance to oils and fats, and heat resistance during bag making.

  An example of JP 2011-12597 A is an example of an ink composition that does not use toluene as an organic solvent in response to such demands and in recent interest in environmental sanitation.

  The required physical properties of printing inks include blocking resistance so that the ink does not adhere to the back side of the film substrate when printed and wound, and blocking resistance so that the printed materials do not adhere to each other. Due to the possibility of air conditioning interruption due to a demand or worst case power outage, the storage conditions for printed materials are becoming more severe, especially in the summer, and the performance of blocking resistance is becoming more important.

JP2011-12597

  The present invention relates to a gravure ink composition for surface printing. More specifically, the ink can be stored for a long period of time, and the discoloration of the antioxidant contained in the film can be reduced when stored under a long period of high temperature and high humidity. Gravure printing ink for surface printing with excellent vinyl chloride blocking resistance, heat resistance, and follow-up properties and excellent environmental sanitation, especially excellent blocking resistance. It relates to a composition.

That is, the present invention
A polyurethane resin (A) obtained by reacting a polymer diol and a diisocyanate; a vinyl chloride / vinyl acetate copolymer (B);
One or more selected from rosin-modified maleic acid (C1), rosin ester (C2) or titanium chelate (D),
A printing ink composition for surface printing containing,
The solid content weight ratio of the polyurethane resin (A) solid content and the vinyl chloride / vinyl acetate copolymer (B) in the surface printing ink composition (calculation formula 1) is 1.0 to 6.0. Yes,
Formula 1
Solid content weight ratio = [solid content weight of polyurethane resin (A)] / [solid content weight of vinyl chloride / vinyl acetate copolymer (B)]

The polyurethane resin (A) relates to a printing ink composition for surface printing, which is the following (A1) to (A2).
(A1) a polymer diol is a combination of several of the polymer diol having a number average molecular weight of 150 to 2000, the number has x species of the polymer diol respective molar ratio in the polymer diol used is at n _i If the average molecular weight m _i (a x = 2 or more integer, i = 1, ···, a x), the range the total number average molecular weight after mixing represented by the formula 2 formula 3 It is.
Formula 2
_{m = m 1 × n 1 +} m 2 × n 2 ··· + m i × n i + ··· + m x × n x
_{(N 1 + n 2 + ···} + n i + · ·· + n x = 1)
Formula 3
200 ≦ m ≦ 500

(A2) in the reaction of the polyurethane resin (A), the the N CO diisocyanates represented by the formula 4, the molar equivalent ratio r of OH of polymeric diol is in the range of formula 5.
Formula 4
r = [Molar equivalent of NCO of diisocyanate] / [Mole equivalent of OH of polymer diol]
Formula 5
1.15 ≦ r ≦ 0.003 × m + 1

  Next, according to the present invention, rosin-modified maleic acid (C1) or rosin ester (C2) has an acid value of 10 to 40 mgKOH / g, and the solid content weight ratio is 0.5 to 5.0% by weight in the total amount of ink. It is related with said ink composition for surface printing characterized by being contained.

  Further, in the present invention, the titanium chelate (D) has a molar equivalent ratio of 0.1 to 1.0 with respect to the hydroxyl group of the vinyl chloride / vinyl acetate copolymer (B). The present invention relates to an ink composition.

  The ink can be stored for a long period of time, and when it is stored for a long period of time under high temperature and high humidity, the discoloration of the antioxidant contained in the film is reduced, and the soft vinyl chloride sheet used for the table cloth and the printed material do not adhere. Provided is a gravure printing ink composition for surface printing, which has excellent polyvinyl chloride blocking resistance, heat resistance and followability, is excellent in environmental sanitation, and is particularly excellent in blocking resistance.

The polyurethane resin (A) comprising a reaction between a polymer diol and diisocyanate will be described.
The polyurethane resin usable in the present invention can be produced by a conventionally known method, and the production method is not particularly limited. For example, a polymer diol and diisocyanate are reacted in an excess ratio of isocyanate groups to prepare a prepolymer having an isocyanate group at the terminal of the polymer diol, and then this is used as a chain extender, a reaction terminator in a solvent. Is a two-stage process. The two-stage method is preferable because a uniform polymer solution can be easily obtained. As the solvent, an ester solvent, a ketone solvent, and an alcohol solvent may be used alone or in combination of two or more.

  Here, usable polymer diols include polyether polyols such as polymers or copolymers of ethylene oxide, propylene oxide, tetrahydrofuran, etc .; ethylene glycol, 1,2-propanediol, 1,3-propanediol 1,3-butanediol, 1,4-butanediol, neopentyl glycol, pentadiol, methylpentadiol, hexadiol, octanediol, nonanediol, methylnonanediol, diethylene glycol, triethylene glycol, dipropylene glycol, etc. Low molecular weight glycols, adipic acid, phthalic acid, isophthalic acid, terephthalic acid, maleic acid, fumaric acid, succinic acid, oxalic acid, malonic acid, glutaric acid, pimelic acid, azelaic acid, sebacic acid, dimer acid, etc. Polyester polyols obtained by dehydration condensation with basic acids or their anhydrides; other polycarbonate diols, polybutadiene glycols, glycols obtained by adding bisphenol A ethylene oxide or propylene oxide; various dimer diols, etc. Known polyols can be mentioned. These polyols may be used alone or in combination of two or more.

  In the present invention, among the polymer diols, polyether diols having side chains are more preferable. Polyether diols having side chains include PPG (polypropylene glycol), PTMG-L (polyoxytetramethylene glycol, manufactured by Sanyo Chemical Co., Ltd.) and PTG-L (polytetramethylene ether glycol, Hodogaya Chemical Co., Ltd.) ).

  The polyether diol having a side chain is used in an amount of 25 to 100 mol% in the polymer diol.

  When the polyether diol is 25 mol% or less in the polymer diol, the vinyl chloride blocking resistance tends to decrease.

The number average molecular weight of the high molecular diol, at the same time to express sufficient anti-blocking properties as ink performance to polyurethane resins suitable for the ink of the number of average molecular weight 150 to 2000 the number of double polymeric diol The total number average molecular weight m after mixing is required to be 200 to 500. That is, when the molar ratio of each of the x types of polymer diols in the polymer diol used is n _i and the number average molecular weight m _i , the total average molecular weight m is expressed by Formula 2 and Formula 3. (X is an integer equal to or greater than 2, i = 1,..., X ).
Formula 2
_{m = m 1 × n 1 +} m 2 × n 2 ··· + m i × n i + ··· + m x × n x
_{(N 1 + n 2 + ···} + n i + · ·· + n x = 1)
Formula 3
200 ≦ m ≦ 500

  If the total number average molecular weight m is 500 or more, it cannot be said that the blocking resistance is sufficient, and if it is 200 or less, it becomes difficult to impart ink stability and printability. In order to obtain this total number average molecular weight m, the number average molecular weight is 2000. When a larger molecular diol is used, the difference in density between the polar part and the non-polar part in the resin becomes too large, and the ink stability is lowered.

  Next, as the usable diisocyanate, various known diisocyanates of aromatic, aliphatic or alicyclic can be mentioned. For example, 1,5-naphthylene diisocyanate, 4,4′-diphenylmethane diisocyanate, 4,4′-diphenyldimethylmethane diisocyanate, 4,4′-dibenzylisocyanate, dialkyldiphenylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate, 1,3- Phenylene diisocyanate, 1,4-phenylene diisocyanate, tolylene diisocyanate, butane-1,4-diisocyanate, hexamethylene diisocyanate, isopropylene diisocyanate, methylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, cyclohexane-1,4-diisocyanate , Xylylene diisocyanate, isophorone diisocyanate, lysine diisocyanate Dicyclohexylmethane-4,4'-diisocyanate, 1,3-bis (isocyanatemethyl) cyclohexane, methylcyclohexane diisocyanate, norbornane diisocyanate, m-tetramethylxylylene diisocyanate, dimerisocyanate obtained by converting the carboxyl group of dimer acid to an isocyanate group, etc. is there.

  Next, the method for producing a polyurethane resin when the polymer diol and diisocyanate are reacted is not particularly limited. For example, the conditions for reacting the polymer diol with the diisocyanate are not particularly limited except that the diisocyanate is excessive, but the isocyanate group / hydroxyl molar equivalent ratio r is greater than 1.15, and the polymer When the total average molecular weight of the diol is m, it is necessary to be within a range smaller than r = 0.003 × m + 1. If the equivalent ratio r of isocyanate group / hydroxyl group is 1.15 or less, it is difficult to obtain a stable synthesis result. On the other hand, if the equivalent ratio r of isocyanate group / hydroxyl group is higher than 0.003 × m + 1, the varnish viscosity becomes too high in a solvent composition suitable for ink-making and is not suitable for ink-making.

  The polyurethane forming reaction may be performed in a solvent or may be performed in a solvent-free atmosphere. In the case of using a solvent, a solvent shown later may be appropriately selected and used from the viewpoints of temperature and viscosity during reaction and control of side reactions. When the polyurethane-forming reaction is carried out in a solvent-free atmosphere, it is desirable to raise the temperature and lower the viscosity to such an extent that stirring is sufficient in order to obtain a uniform polyurethane resin. The urethanization reaction is desirably carried out for 10 minutes to 5 hours, and the end point of the reaction is judged by viscosity measurement, NCO peak by IR measurement, NCO% measurement by titration, and the like.

  Furthermore, a polymer diol and diisocyanate are reacted to synthesize a prepolymer having a terminal isocyanate group, and then a urea bond is introduced into the polyurethane resin using a chain extender and a reaction terminator to obtain a polyurethane / urea resin. Thus, the physical properties of the coating film are further improved.

  In the present invention, the polyurethane resin includes a polyurethane-urea resin having a urea bond.

  Next, various known amines can be used as a chain extender that can be used when a urea bond is introduced. For example, ethylenediamine, propylenediamine, hexamethylenediamine, triethylenetetramine, diethylenetriamine, isophoronediamine, dicyclohexylmethane-4,4'-diamine and the like can be mentioned. In addition, 2-hydroxyethylethylenediamine, 2-hydroxyethylpropylenediamine, di-2-hydroxyethylethylenediamine, di-2-hydroxyethylpropylenediamine, 2-hydroxypropylethylenediamine, di-2-hydroxypropylethylenediamine, etc. Representative examples thereof include diamines having a hydroxyl group and dimer diamine obtained by converting a carboxyl group of dimer acid into an amino group.

  Examples of the reaction terminator include dialkylamines such as di-n-butylamine and alcohols such as ethanol and isopropyl alcohol.

  The production method for introducing the urea bond into the polyurethane resin is not particularly limited, but the chain extender and the reaction terminator when the number of free isocyanate groups at both ends of the prepolymer is 1 are used. It is preferable that the total quantity of the amino groups in it is in the range of 0.5 to 1.3. When the total number of amino groups is less than 0.5, the drying property, blocking resistance and coating strength are not sufficient, and when it exceeds 1.3, the chain extender and the reaction terminator remain unreacted. , Odor is likely to remain on the printed matter.

  The vinyl chloride / vinyl acetate copolymer (B) used in the present invention is obtained by copolymerizing a vinyl chloride monomer and a vinyl acetate monomer. The vinyl chloride / vinyl acetate copolymer having a hydroxyl group can further use vinyl alcohol in the copolymerization or saponify a part of vinyl acetate. In the vinyl chloride / vinyl acetate copolymer having a hydroxyl group, the properties of the resin film and the resin dissolution behavior are determined by the monomer ratio of vinyl chloride, vinyl acetate and vinyl alcohol. That is, vinyl chloride imparts toughness and hardness of the resin coating, vinyl acetate imparts adhesion and flexibility, and vinyl alcohol imparts good solubility in polar solvents. In the present invention, the vinyl chloride / vinyl acetate copolymer (B) preferably has a hydroxyl group.

  In the present invention, the hydroxyl value of the vinyl chloride / vinyl acetate copolymer (B) is preferably 60 to 170 mgKOH / g. In the present invention, the solid content weight ratio between the polyurethane resin (A) and the vinyl chloride / vinyl acetate copolymer (B) needs to be 1.0 to 6.0. When the solid content weight ratio of the polyurethane resin (A) and the vinyl chloride / vinyl acetate copolymer (B) is 1.0 or less, the followability is lowered, and when it is 6.0 or more, the polyvinyl chloride blocking resistance is lowered. There is a tendency.

  Rosin-modified maleic acid (C1) refers to a product obtained by reacting rosins with maleic acid by a known method. In this case, the reaction temperature is about 150 to 300 ° C., and the reaction temperature time is about 1 to 24 hours. The amount of maleic acid charged is about 20 parts by weight or less of maleic acid with respect to 100 parts by weight of rosins.

  For rosin ester (C2), a method of dehydrogenating the esterified product obtained after esterifying hydrogenated rosin and alcohol, or esterifying and dehydrogenating hydrogenated rosin and alcohol in the presence of a dehydrogenation catalyst It is obtained by advancing the reaction.

  Hydrogenated rosin partially or completely hydrogenated gum rosin, wood rosin, tall oil rosin mainly composed of resin acids such as abietic acid, parastrinic acid, neoabietic acid, pimaric acid, isopimaric acid, dehydroabietic acid It is obtained after purification.

  Examples of alcohol components include monohydric alcohols such as n-octyl alcohol, 2-ethylhexyl alcohol, decyl alcohol, and lauryl alcohol; dihydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, and neopentyl glycol; glycerin and trimethylolethane. And trihydric alcohols such as trimethylolpropane and cyclohexanedimethanol; and tetrahydric alcohols such as pentaerythritol and diglycerin. In the reaction, an esterification catalyst is not necessarily required. However, in order to shorten the reaction time, acid catalysts such as acetic acid and paratoluenesulfonic acid, alkali metal hydroxides such as calcium hydroxide, calcium oxide, magnesium oxide, etc. It is also possible to use metal oxides.

  The composition of the rosin ester (C2) used in the present invention is preferably less than 1% abietic acid, 10 to 50% by weight tetrahydroabietic acid, 10 to 40% by weight dihydroabietic acid, and 20 to 60% by weight dehydroabietic acid.

  The acid value of the rosin ester (C2) and rosin-modified maleic acid (C1) is preferably 10 to 40 mgKOH / g. When it is smaller than 10 mgKOH, the polyvinyl chloride blocking resistance is lowered, and when it is larger than 40 mgKOH / g, the compatibility with the binder resin is deteriorated. The amount added is preferably 0.5 to 5.0% by weight in the ink composition in terms of solid content. When the content is 0.5% by weight or less, the vinyl chloride blocking resistance is lowered. When the content is 5.0% by weight or more, the ink becomes incompatible and is separated.

  Titanium chelate (D) is a component used to achieve an improvement in cohesive strength in ink, and has a Ti—O—C type bond in one molecule. Specifically, titanium alkoxide, Examples include titanium chelates such as titanium acylate.

  Typical examples of the titanium chelate (D) include titanium alkoxides such as tetraisopropyl titanate, tetranormal butyl titanate, butyl titanate dimer, tetra (2-ethylhexyl) titanate, tetramethyl titanate, tetrastearyl titanate, triethanolamine titanate, titanium Mention may be made of titanium chelates such as acetyl acetate, titanium ethyl acetoacetate, titanium lactate, octylene glycol titanate and titanium tetraacetylacetonate. Among these, chelate-type titanium organic compounds generally require heating to complete the crosslinking reaction, but are hardly hydrolyzed at room temperature and have excellent stability and are suitable for use in inks. In particular, those having an amine in the molecule can be preferably used.

  Titanium chelate (D) contributes to the intermolecular or intramolecular crosslinking of the resin by having an alkoxy group in one molecule.

  It is preferable that the titanium chelate (D) has a molar equivalent ratio of 0.1 to 1.0 with respect to the hydroxyl group of the vinyl chloride / vinyl acetate copolymer (B). In the case of 0.1 molar equivalent or less, the vinyl chloride blocking resistance is lowered. Moreover, when it is 1.0 molar equivalent or more, the temporal stability of the ink is inferior.

  Pigments that can be used in the present invention include various inorganic pigments that can generally be used in printing inks and paints, such as colored pigments such as titanium oxide, bengara, bitumen, ultramarine, carbon black, graphite, and calcium carbonate, kaolin, clay. And extender pigments such as barium sulfate, aluminum hydroxide and talc. Furthermore, examples of organic pigments include soluble azo pigments, insoluble azo pigments, azo chelate pigments, condensed azo pigments, copper phthalocyanine pigments, and condensed polycyclic pigments. The content of these pigments is 0.5 to 50% by weight in the ink composition.

  Next, as the solvent used in the ink composition of the present invention, alcohol organic solvents such as methanol, ethanol, n-propanol, isopropanol and butanol, and ketone organic solvents such as acetone, methyl ethyl ketone and methyl isobutyl ketone are mainly used. Ester organic solvents such as methyl acetate, ethyl acetate, propyl acetate and butyl acetate, aliphatic hydrocarbon organic solvents such as n-hexane, n-heptane and n-octane, and cyclohexane, methylcyclohexane, ethylcyclohexane, Examples thereof include alicyclic hydrocarbon organic solvents such as cycloheptane and cyclooctane, and it is preferable to use them by mixing in consideration of solubility and drying property of the binder resin. The amount of these organic solvents used is 30% by weight or more in ordinary ink.

  Furthermore, in the present invention, various hard resins and waxes can be added for the purpose of improving adhesiveness and various resistances.

  Here, examples of the hard resin include dimer acid resin, maleic acid resin, petroleum resin, terpene resin, ketone resin, dammar resin, copal resin, and chlorinated polypropylene. When these hard resins are used, an effect of improving adhesiveness can be expected particularly for a plastic film that has not been surface-treated.

Moreover, in the gravure printing ink for surface printing, a crosslinking agent and a wax component can be contained for the purpose of improving heat resistance, oil resistance, and friction resistance.
On the other hand, various known waxes such as polyolefin wax and paraffin wax can be used as the wax.

  Furthermore, the addition of various ink additives such as pigment dispersants, leveling agents, surfactants, and plasticizers is optional.

  As a method for producing printing ink using these materials, first, after stirring and mixing a pigment, a binder resin, an organic solvent, and, if necessary, a pigment dispersant, a surfactant, and the like, There is a method of kneading using a bead mill, a ball mill, a sand mill, an attritor, a roll mill, a pearl mill or the like, and further adding and mixing the remaining materials.

The ink composition for surface printing obtained from the above materials and production method can be printed on an adherend such as various plastic films by a gravure printing method. Specifically, examples of the printable plastic film include stretched and unstretched polyolefins such as polyethylene and polypropylene, polyester, nylon, cellophane, and vinylon.
Furthermore, the obtained printed matter is made into a bag and used for a packaging container such as food.

EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, this invention is not limited to these Examples. In the present invention, “parts” and “%” represent “parts by weight” and “% by weight” unless otherwise noted.

 The hydroxyl value was acetylated with an excess of an acetylating reagent and the amount of hydroxyl group in 1 g of resin calculated by back titrating the remaining acid with alkali was converted to mg of potassium hydroxide. It is a value performed according to JISK0070. The amine value is the number of mg of potassium hydroxide equivalent to the equivalent amount of hydrochloric acid required to neutralize the amino group contained in 1 g of resin. The acid value is the number of mg of potassium hydroxide required to neutralize the acid group contained in 1 g of resin, and the measurement method may be a known method, generally according to JIS K0070 (1996). Done. The molecular weight was determined as a polystyrene-converted molecular weight by measuring the molecular weight distribution using a GPC (gel permeation chromatography) apparatus.

<Synthesis of polyurethane resin>
(Synthesis Example 1)
In a four-necked flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen gas inlet tube, polypropylene glycol (P400, manufactured by ADEKA) with a number average molecular weight (hereinafter referred to as Mn) of 4007.0 parts, isophorone diisocyanate 593.1 Parts, stannous 2-ethylhexylate and 200 parts of ethyl acetate were charged, reacted at 90 ° C. for 3 hours under a nitrogen stream, cooled by adding 369.7 parts of ethyl acetate, and solvent for terminal isocyanate prepolymer 1800.0 parts of solution were obtained. Next, 1500.5 parts of the obtained terminal isocyanate prepolymer was gradually added to a mixture of 148.1 parts of isophoronediamine, 1.6 parts of di-n-butylamine, 949.9 parts of ethyl acetate and 1400 parts of isopropyl alcohol at room temperature. And then reacted at 50 ° C. for 1 hour to obtain a polyurethane resin (a1) having a solid content of 30% and a weight average molecular weight of 20000.

(Synthesis Examples 2 to 11)
Polyurethane resins (a2) to (a11) were synthesized in the same manner as in Synthesis Example 1 with the formulation shown in Table 1. The polypropylene glycol used was made by ADEKA, and the tripropylene glycol was made by Wako Pure Chemical. In addition, about the thing (a11) whose reaction did not fully advance, it excluded from subsequent evaluation.

<Preparation of vinyl chloride / vinyl acetate copolymer varnish>
25 parts of vinyl chloride / vinyl acetate copolymer (Solvain TA5R manufactured by Nissin Chemical Co., Ltd.) was mixed and dissolved in 75 parts of ethyl acetate to give a vinyl chloride / vinyl acetate copolymer varnish (bivinyl chloride (b11)). Got. Hydroxyl value 166.3 KOHmg / g.

<Preparation of titanium chelate additive>
41 parts of tetraisopropyl titanate (TPT manufactured by Mitsubishi Gas Chemical Co., Inc.) was mixed with 59 parts of acetylacetone to obtain titanium acetylacetonate to obtain titanium chelate (d11).

<Preparation of rosin-modified maleic resin varnish>
50 parts of rosin-modified maleic acid (Marquide 5 manufactured by Arakawa Chemical Co., Ltd., acid value: 25 mg KOH / g) is mixed and dissolved in 50 parts of ethyl acetate to obtain a rosin-modified maleic resin varnish (rosin resin varnish (c11)). It was. Solid content 50%. Other rosin-modified maleic acids were prepared in the same manner.
1) Rosin resin varnish (C2): Marquide 2 (Arakawa Chemical Co., Ltd., acid value: 39 mgK)
OH / g)

<Adjustment of rosin ester resin varnish>
50 parts of rosin ester resin (acid value 11 mgKOH / g, manufactured by Arakawa Chemical Co., Ltd.) was mixed and dissolved in 50 parts of ethyl acetate to obtain a rosin ester resin varnish (rosin resin varnish (C3)). Solid content 50%.
Further, rosin-modified phenol resin Tamanol 803L (manufactured by Arakawa Chemical Co., Ltd., acid value 47 mgKOH / g) was used as a comparative example. Rosin resin varnish (C4), solid content 50%.

<Example 1>
22 parts of titanium oxide (Titanics JR-808, manufactured by Teika Co., Ltd.), 20 parts of polyurethane resin (polyurethane resin (a1)), 17 parts of vinyl chloride / vinyl acetate copolymer (bivarnish of salt vinegar (b11)), rosin Modified maleic acid resin (rosin resin (c11)) 5 parts, tetraisopropyl titanate (titanium chelate (d11)) 1 part, and methyl ethyl ketone: n-propyl acetate: ethyl acetate: isopropyl alcohol = 40: 25: 45: 5 (weight) Ratio) was mixed with a sand mill to prepare a test ink composition (ink 1).

<Examples 2 to 6><Comparative Examples 1 to 4>
According to the recipe shown in Table 2, ink compositions for surface printing (inks 2 to 10) were obtained in the same manner as in Example 1.

The ink compositions obtained in Examples 1 to 6 and Comparative Examples 1 to 4 were evaluated for stability over time, and the printed materials using the ink compositions were evaluated for blocking resistance, heat resistance and followability.
In printing, the printing ink composition is diluted with a diluting solvent (methyl ethyl ketone: n-propyl acetate: ethyl acetate: isopropyl alcohol = 40: 25: 45: 5 (weight ratio)), and 15% with Zahn cup N0.3. The ink was adjusted to seconds and used as printing ink.
Next, a corona discharge-treated polypropylene film (FOH, manufactured by Futamura Chemical Co., Ltd.) was printed with a corrosive plate having a plate depth of 30 microns using a gravure proofing machine, and an evaluation sample was obtained after one day. Evaluation methods and evaluation criteria are as follows. The evaluation results are shown in Table 3.

(Stability evaluation over time)
The ink was left at 40 ° C. for 1 week, and the occurrence of separation and precipitation was evaluated.
A: No separation and / or precipitation occurred.
○: Separation and / or precipitation occurred slightly.
Δ: Vigorous separation and / or precipitation occurred. And / or gelled.

(Evaluation of blocking resistance)
Cut the printed material into 4cm squares, superimpose the printed surfaces, apply a load of 0.5 kg / cm2, leave it in an atmosphere of 50 ° C and 80% RH for 24 hours, peel off the printed surface, and the degree of ink peeling From this, blocking resistance was evaluated.
A: The ink did not peel at all.
○: The area where the ink peeled from the film was 20 to 50%.
(Triangle | delta): The area where the ink peeled from the film exceeds 50 to 75%.
X: The area where the ink peeled from the film exceeded 75%.

(Heat resistance evaluation)
The aluminum foil cut to the same size as the printed material is placed on top of the printed surface and pressed with a heat seal tester at a pressure of 2 kg / cm2 for 1 second, and the ink starts from the lowest temperature at which the ink transfers to the aluminum foil. The heat resistance of the composition was evaluated.
A: Minimum temperature is 160 ° C. or higher. ○: Minimum temperature is 140 ° C. or higher and lower than 160 ° C.
(Triangle | delta): The minimum temperature is less than 140 degreeC.

(Followability evaluation)
The followability of the ink film to the substrate was evaluated by four steps of peeling and breaking the ink receiving layer by stretching the substrate on which the ink was printed to 400%.
A: There is no peeling or destruction of the ink film.
○: There is no peeling or destruction of the ink film, but the gloss changes in part.
(Triangle | delta): There exists peeling and destruction in a part of ink film.
X: The ink film completely peels or breaks.

Claims (3)

A polyurethane resin (A) obtained by reacting a polymer diol and a diisocyanate;
A vinyl chloride / vinyl acetate copolymer (B);
A printing ink composition for surface printing, comprising at least one selected from rosin-modified maleic acid (C1), rosin ester (C2) or titanium chelate (D),
The solid content weight ratio of the polyurethane resin (A) solid content and the vinyl chloride / vinyl acetate copolymer (B) in the surface printing ink composition (calculation formula 1) is 1.0 to 6.0. Yes,
Formula 1
Solid content weight ratio = [solid content weight of polyurethane resin (A)] / [solid content weight of vinyl chloride / vinyl acetate copolymer (B)]

The printing ink composition for surface printing, wherein the polyurethane resin (A) is the following (A1) to (A2).
(A1) a polymer diol, the number is a combination of several of the polymer diol of average molecular weight 150 to 2000, x species polymeric diol respective molar ratio in the polymer diol to be used is located in n _i If the number average molecular weight m _i (x = an integer of 2 or more, i = 1, ···, a x), the total number average molecular weight after mixing represented by the formula 2 formula 3 It is a range.
Formula 2
_{m = m 1 × n 1 +} m 2 × n 2 ··· + m i × n i + ··· + m x × n x
_{(N 1 + n 2 + ···} + n i + · ·· + n x = 1)
Formula 3
200 ≦ m ≦ 500

(A2) In the reaction of the polyurethane resin (A), the molar equivalent ratio r of the diisocyanate NCO represented by the calculation formula 4 and the OH of the polymer diol is within the range of the calculation formula 5.
Formula 4
r = [Molar equivalent of NCO of diisocyanate] / [Mole equivalent of OH of polymer diol]
Formula 5
1.15 ≦ r ≦ 0.003 × m + 1
  The rosin-modified maleic acid (C1) or rosin ester (C2) has an acid value of 10 to 40 mgKOH / g, and is contained in the total amount of ink in a solid content weight ratio of 0.5 to 5.0% by weight. The ink composition for surface printing according to claim 1. 3. The surface printing material according to claim 1, wherein the titanium chelate (D) has a molar equivalent ratio of 0.1 to 1.0 with respect to the hydroxyl group of the vinyl chloride / vinyl acetate copolymer (B). Ink composition.