JP2012012597A - Gravure ink composition for front printing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gravure ink composition for front printing capable of long term storage of the ink, capable of reducing discoloration of antioxidant contained in a film in the storage under long term high temperature/high humidity, having good anti-blocking characteristics, heat resistance and followability, which prevent sticking of a soft vinyl chloride sheet used for tablecloth and the like and printed matter, and also having excellent environmental hygiene.SOLUTION: The gravure ink composition for front printing includes a polyurethane resin (A) made by the reaction between polymer diol and diisocyanate, vinyl chloride/vinyl acetate copolymer (B), rosin-modified maleic acid or rosin ester (C) and/or titanium chelate (D).

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. In particular, the present invention relates to a gravure printing ink composition for surface printing, which has excellent vinyl chloride blocking resistance, heat resistance, and follow-up properties so that the printed product does not adhere to the soft vinyl chloride sheet used in the above, and is excellent in environmental sanitation.

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.

Furthermore, recently, the number of manufacturers that tackle environmental problems has increased, and there is a movement to configure products using materials that are excellent in environmental sanitation. For example, in the organic solvent used in printing ink,
Research has been done not to select toluene.

Thus, in JP-A-9-296143, etc., an ink containing a polyamide resin that does not contain toluene and a cellulose derivative as a binder is disclosed, but an ink that mainly contains a polyamide resin is not suitable for high-speed printing, There has been a problem that the ink is transferred to the reversing roll of the printing press and the appearance of the printed matter is impaired.

On the other hand, as an ink suitable for high-speed printing without containing toluene, an ink using a polyurethane resin and nitrocellulose as a binder has been used. For example, JP2002-2002
294128 and the like.

However, the ink using a polyurethane resin and nitrocellulose as a binder is the same as that published by the Japanese Society of Fire Pharmacy, when a film containing a phenolic antioxidant is used. Vol. 63, No
. As reported in US Pat. No. 3,2002, decomposition of nitrocellulose is promoted and NOx is generated when left in a high temperature and high humidity condition for a long time. The problem that the generated NOx reacts with the phenolic antioxidant and the phenolic antioxidant has a quinone structure and causes discoloration of the film is well known.

JP-A-9-296143 JP 61-37851 A Japanese Patent Application No.7-183039 JP 2002-294128 A

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. In particular, the present invention relates to a gravure printing ink composition for surface printing, which has excellent vinyl chloride blocking resistance, heat resistance, and follow-up properties so that the printed product does not adhere to the soft vinyl chloride sheet used in the above, and is excellent in environmental sanitation.

The ink composition for surface printing of the present invention is
A polyurethane resin (A) obtained by reacting a polymer diol and a diisocyanate;
Vinyl chloride / vinyl acetate copolymer (B),
Rosin-modified maleic acid or rosin ester (C)
And / or titanium chelate (D)
In the ink composition containing
High molecular diol
Polyether diol having a side chain 25 to 100 mol%
And
A polyurethane resin (A) obtained by reacting a polymer diol and diisocyanate,
Molar ratio represented by calculation formula (1) 1.5 to 3.0
And, moreover,
A polyurethane resin (A) obtained by reacting a polymer diol and diisocyanate and a vinyl chloride / vinyl acetate copolymer (B),
Solid content weight ratio 1.0-6.0 represented by Formula (2)
It is related with the ink composition for surface printing characterized by these.
Formula (1)
Formula (2)

In the present invention, rosin-modified maleic acid or rosin ester (C)
Acid value 10-40mgKOH / g
And
In the total amount of ink, the solid content weight ratio is 0.5 to 5.0% by weight.
It is related with said ink composition for surface printing characterized by being contained.

Further, in the present invention, the titanium chelate (D) is
The present invention relates to the above-mentioned ink composition for surface printing, which is 0.1 to 1.0 equivalent relative to the hydroxyl group of the vinyl chloride / vinyl acetate copolymer (B).

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 is excellent in anti-vinyl chloride blocking property, heat resistance and followability and is excellent in environmental sanitation.

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 compound and a diisocyanate compound are reacted in an excess ratio of the isocyanate group to prepare a prepolymer having an isocyanate group at the terminal of the polymer diol, and then this is used as a chain extender in the solvent to stop the reaction. There is a two-stage method in which an agent is reacted. 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 diol compounds include ethylene oxide, propylene oxide,
Polyether polyols such as tetrahydrofuran or other polymers or copolymers; 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 and other low molecular weight glycols, adipic acid, phthalic acid, isophthalic acid, terephthalic acid, Polyester polyesters obtained by dehydration condensation of dibasic acids such as maleic acid, fumaric acid, succinic acid, oxalic acid, malonic acid, glutaric acid, pimelic acid, azelaic acid, sebacic acid, dimer acid or their anhydrides. Ols; can various known polyols such as dimer diols include; other polycarbonate diols, polybutadiene glycols, glycol obtained by adding bisphenol A ethylene oxide or propylene oxide. These polyols may be used alone or in combination of two or more.

In the present invention, it is necessary to use a polyether diol having a side chain. Polyether diols with side chains include PPG (polypropylene glycol) and PTMG
-L (polyoxytetramethylene glycol, manufactured by Sanyo Chemical Co., Ltd.) and PTG-L (polytetramethylene ether glycol, manufactured by 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 polymer diol is appropriately determined in consideration of the solubility, drying property, blocking resistance and the like of the resulting polyurethane resin, but usually 500 to 6000 is preferable. When the molecular weight is less than 500, the printability tends to be inferior with a decrease in solubility, and when it exceeds 6000, the drying property and blocking resistance are lowered.

Next, examples of the organic diisocyanate compound that can be used include various known diisocyanates of aromatic, aliphatic, and alicyclic groups. 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 the polyurethane resin when the polymer diol compound and the diisocyanate are reacted is not particularly limited. For example, the conditions for reacting the polymer diol compound and diisocyanate are not particularly limited except that the diisocyanate is excessive, but the equivalent ratio of isocyanate group / hydroxyl group is 1.5 / 1 to 3.0 / 1. It is desirable to be within the range. When the equivalent ratio of isocyanate group / hydroxyl group is 1.5 / 1 or less, the obtained polyurethane resin is fragile, and therefore, when used in printing ink, vinyl chloride blocking tends to occur.
On the other hand, if the equivalent ratio of isocyanate group / hydroxyl group is higher than 3.0 / 1, free isocyanate residues that are not used in the reaction increase, and the stability of the ink over time is poor.

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, after reacting the polymer diol compound and diisocyanate to synthesize a prepolymer having a terminal isocyanate group, 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 60 to 170.
mgKOH / g is preferred. In the present invention, the solid content ratio between the polyurethane resin (A) and the vinyl chloride / vinyl acetate copolymer (B) is required to be 1.0 to 6.0. When the solid content 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 6.0 or more, the vinyl chloride blocking resistance tends to be lowered. It is in.

Rosin-modified maleic acid (C1) refers to a product obtained by reacting the above 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 1 to 2.
About 4 hours. The amount of maleic acid charged was 2 maleic acids per 100 parts by weight of rosins.
It is about 0 part by weight or less.

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 used in the present invention is preferably less than 1% abietic acid, 10-50% by weight tetrahydroabietic acid, 10-40% by weight dihydroabietic acid, and 20-60% by weight dehydroabietic acid.

The acid value of the rosin ester and rosin-modified maleic acid is preferably 10 to 40 mgKOH / g. If it is smaller than 10 mgKOH, the vinyl chloride blocking resistance is deteriorated.
When it is larger than mgKOH / g, the compatibility with the binder resin is deteriorated, which is not preferable. Moreover, it is preferable that it is 0.5 to 5.0% by solid content ratio in an ink composition about addition amount. When the content is 0.5% or less, the effect on the polyvinyl chloride blocking resistance is reduced, and 5
. When the content is 0% 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.

The ratio of the titanium chelate (D) to the hydroxyl group of the vinyl chloride / vinyl acetate copolymer (B) is preferably 0.1: 1 to 1: 1. In the case of 0.1 equivalent or less, the effect on the PVC blocking resistance is reduced. Moreover, when it is 1.0 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, butyl acetate, n-hexane,
Examples include aliphatic hydrocarbon organic solvents such as n-heptane and n-octane, and alicyclic hydrocarbon organic solvents such as cyclohexane, methylcyclohexane, ethylcyclohexane, cycloheptane, and cyclooctane, and binder resins. It is preferable to use them by mixing in consideration of the solubility and drying properties of these. 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 demonstrates this invention more concretely, this invention is not limited to an Example. Unless otherwise specified, in this example, “part” and “%”
"Represents" parts by weight "and"% by weight ".

<Synthesis of polyurethane resin>
(Synthesis Example 1)
Number average molecular weight (hereinafter referred to as Mn) obtained from adipic acid and 3-methyl-1,5-pentanediol in a four-necked flask equipped with a stirrer, thermometer, reflux condenser and nitrogen gas inlet tube
2000 polyester diol (PMPA2000, Kuraray) 520.8 parts, Mn
520.8 parts of 2000 polypropylene glycol (PPG2000, manufactured by NOF Corporation),
First, 266.7 parts of isophorone diisocyanate, 0.25 parts of stannous 2-ethylhexylate and 200 parts of ethyl acetate were added, reacted at 85 ° C. for 3 hours under a nitrogen stream, cooled by adding 366.0 parts of ethyl acetate, 1874.6 parts of a solvent solution of an isocyanate prepolymer were obtained. Next, 91.3 parts of isophoronediamine, 1.54 parts of di-n-butylamine, 6.2 parts of aminoethylethanolamine, 1200 parts of ethyl acetate and 1120 parts of isopropyl alcohol were mixed with the resulting terminal isocyanate prepolymer 1581. .1 part was gradually added 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 35,000.
Polyurethane resins (A2) to (A7) were synthesized in the same manner as in Synthesis Example 1 with the formulation shown in Table 1.

<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 (B1)). 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 form titanium acetylacetonate, and titanium chelate (D1
)

<Preparation of rosin-modified maleic resin varnish>
Rosin-modified maleic acid (Marquide 5 manufactured by Arakawa Chemical Co., Ltd., acid value: 25 mgKOH / g
50 parts of ethyl acetate was mixed and dissolved in 50 parts of ethyl acetate to obtain a rosin-modified maleic resin varnish (rosin resin varnish (C1)). 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>
Titanium oxide (Titanics JR-808, manufactured by Teika Co., Ltd.) 22 parts, polyurethane resin (polyurethane resin (A1)) 20 parts, vinyl chloride / vinyl acetate copolymer (salt vinegar (V1) (B1)) 17 parts, rosin 5 parts of modified maleic acid resin (rosin resin (C1)), 1 part of tetraisopropyl titanate (titanium chelate (D1)), and methyl ethyl ketone: n-propyl acetate: ethyl acetate: isopropyl alcohol = 40: 25: 45: 5 (weight) Ratio) was kneaded with a sand mill to prepare a test ink composition (ink 1).

<Examples 2 to 12><Comparative Examples 1 to 6>
According to the recipes shown in Tables 2 and 3, surface printing ink compositions (inks 2 to 20) were obtained in the same manner as in Example 1.

The ink compositions obtained in Examples 1 to 12 and Comparative Examples 1 to 6 and the printed matter using the ink compositions were evaluated for stability over time, PVC blocking resistance, heat resistance, and followability.
In printing, the printing ink composition is diluted with a diluent solvent (methyl ethyl ketone: n-propyl acetate: ethyl acetate: isopropyl alcohol = 40: 25: 45: 5 (weight ratio)).
And adjusted to 15 seconds with a Zahn cup N0.3 to obtain a 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 4.

(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.

(PVC blocking resistance evaluation)
Laminate a soft vinyl chloride sheet cut to the same size as the printed material and the printed surface, 0.5
A load of kg / cm 2 was applied and left in an atmosphere of 50 ° C. and 80% RH for 24 hours, and then 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 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;
Vinyl chloride / vinyl acetate copolymer (B),
Rosin-modified maleic acid or rosin ester (C)
And / or titanium chelate (D)
In the ink composition containing
High molecular diol
Polyether diol having a side chain 25 to 100 mol%
And
A polyurethane resin (A) obtained by reacting a polymer diol and diisocyanate,
Molar ratio represented by calculation formula (1) 1.5 to 3.0
And, moreover,
A polyurethane resin (A) obtained by reacting a polymer diol and diisocyanate and a vinyl chloride / vinyl acetate copolymer (B),
Solid content weight ratio 1.0-6.0 represented by Formula (2)
An ink composition for surface printing, characterized in that
Formula (1)

Formula (2)
Rosin-modified maleic acid or rosin ester (C)
Acid value 10-40mgKOH / g
And
In the total amount of ink, the solid content weight ratio is 0.5 to 5.0% by weight.
The ink composition for surface printing according to claim 1, which is contained. Titanium chelate (D)
The ink composition for surface printing according to claim 1 or 2, wherein the amount is 0.1 to 1.0 equivalent to the hydroxyl group of the vinyl chloride / vinyl acetate copolymer (B).