JPH1067959A - Printing ink composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a printing ink composition giving a film having excellent adhesiveness, heat resistance, oil resistance and storage stability and useful for printing on a plastic film by mixing pigment, a hydroxyl group-containing binder resin, a specific crosslinking agent and an organic solvent. SOLUTION: This composition is mainly composed of (A) pigment, (B) a hydroxyl group-containing resin (preferably a polyamide resin and/or a cellulose derivative), (C) a titanium-based crosslinking agent comprising a reaction product obtained by reacting (i) a titanate compound of the formula I X is a 3-18C alkyl or acyl; (j) is 0-9} with (ii) di(polyoxyethylene alkylether) phosphate of the formula II Y is a 1-18C alkyl; (m) and (n) are each positive integer and (m+n)=2-10} so as a molar ratio of the components (i)/(ii)} to be (0.5/1)-(4/1) in an amount of 0.1-5wt.% of the whole composition of the ink and (D) an organic solvent. As the component (i), tetraisopropoxytitanium is exemplified. As the component (ii), dipolyoxyethylene (2) phosphate is exemplified.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solvent-based printing ink composition, and more particularly, to a solvent-based printing ink composition having excellent adhesiveness, heat resistance, and oil resistance and excellent storage stability over time. About.

[0002]

2. Description of the Related Art Polyamide resins and cellulose derivatives are often used as binder resins for printing inks for various plastic films.

[0003] For example, a simple configuration in which ink is printed only on the front side of an adherend on a bag of confectionery or rice, and is not printed on the back side in contact with food (called a front printing method).
A typical binder resin of the printing ink for surface printing is generally a polyamide resin alone or in combination with a cellulose derivative.

[0004] This is because the properties required for printing inks for surface printing are mainly gloss, adhesiveness, heat resistance, oil resistance and the like. Polyamide resins have gloss and adhesiveness, and cellulose derivatives have heat resistance. To be given.

However, the polyamide resin alone does not provide sufficient heat resistance, and the combined use with a cellulose derivative tends to reduce the gloss of the ink and the adhesion to various films. It is difficult to obtain an ink composition that simultaneously satisfies high heat resistance, gloss, and adhesion.

Therefore, as a method for improving the required performance, a method of adding an alkyl titanate as a crosslinking agent in an ink composition is known. However, yellowing of the ink and storage stability over time are reduced. There's a problem.

The applicant of the present invention has proposed a method of adding titanium stearate as a crosslinking agent (Japanese Patent Application No. 7-183039).
However, when the content of the cross-linking agent is increased, there is a problem that the resulting printing ink composition has insufficient oil resistance.

Further, a system in which a reactant of a titanium orthoester and a monoalkyl phosphate or a dialkyl phosphate is added has been proposed in Japanese Patent Application Laid-Open No. 61-37851, but these systems have a sufficient effect. In order to obtain the compound (1), there is a problem that the content of the cross-linking agent is increased and storage stability with time is reduced.

[0009] On the other hand, packaging bags for food packaging or boil retorting, which require high quality, have a structure in which ink is printed on the back surface of an adherend and a film is laminated on the printed surface (back printing printing method). Is used, but a typical binder resin of the printing ink for back printing is a polyurethane resin. This is because the performance required for printing inks for back printing is mainly due to the adhesion to a wide range of types of films, heat resistance and heat resistance to withstand lamination strength, boil and retort treatment, etc. It is difficult to satisfy these performances in the system.

In order to solve this problem, Japanese Patent Application Laid-Open No.
Although the method proposed in Japanese Patent Application Publication No. 1-37851 can be used, its effect is still insufficient.

[0011]

Accordingly, an object of the present invention is to provide an ink film having good adhesiveness, heat resistance and oil resistance when printed on various plastic films, and furthermore, have a storage stability over time. To provide a good printing ink composition.

[0012]

That is, the present invention provides a printing ink composition mainly comprising a pigment, a hydroxyl group-containing resin, a titanium-based crosslinking agent and an organic solvent, wherein the titanium-based crosslinking agent has the following general formula (I): At least one type of the titanate compound represented by 1) (component (a)) and at least one type of di (polyoxyethylene alkyl ether) phosphate represented by the general formula (2) (component (b))
It is a reaction product in which the molar ratio of component a: component b is (0.5 to 4): 1 and is contained in the range of 0.1 to 5% by weight of the total composition of the printing ink. A printing ink composition characterized by the following:

[0013]

Embedded image

Here, X is each independently 3 carbon atoms.
To 18 alkyl groups or acyl groups, and Y each independently represents an alkyl group having 1 to 18 carbon atoms. Also, j is an integer from 0 to 9, m and n are positive integers, and m + n = 2
Meet 10.

The present invention also relates to a printing ink composition using a polyamide resin and / or a cellulose derivative as the hydroxyl-containing resin.

The present invention also relates to a printing ink composition using a polyurethane resin as the hydroxyl-containing resin.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail.

<Pigment> First, as the pigment used in the ink composition of the present invention, an inorganic, organic pigment or extender pigment which can be generally used in an organic solvent type ink composition can be used.

Specifically, as inorganic pigments, titanium oxide, red iron oxide, antimony red, cadmium red,
Organic pigments such as cadmium yellow, cobalt blue, navy blue, ultramarine, carbon black, and graphite include soluble azo pigments, insoluble azo pigments, azo lake pigments, condensed azo pigments, copper phthalocyanine pigments, condensed polycyclic pigments, and the like.

Further, examples of extenders include calcium carbonate, kaolin, clay, barium sulfate, aluminum hydroxide, and talc.

The content of these pigments in the ink composition is usually about 1 to 50% by weight.

<Binder Resin> The binder resin used in the ink composition of the present invention is a hydroxyl group-containing resin,
It is mainly a polyamide-cellulose derivative mixed system or a polyurethane system, and other resins can be added as needed.

Polyamide resin The polyamide resin that can be used as a binder resin of the ink composition of the present invention is mainly a polymerized fatty acid,
An acid component which may partially contain an alicyclic and aromatic dicarboxylic acid or an aliphatic monocarboxylic acid, and mainly aliphatic, alicyclic, araliphatic and aromatic polyamines alone or in a mixture, and further, primary And an amine component which may partially contain a secondary monoamine.

Here, the polymerized fatty acid generally has 1 carbon atom.
It is obtained by polymerization of 6 to 22 unsaturated fatty acids or esters thereof, and contains monobasic fatty acids, dimerized polymerized fatty acids, trimerized polymerized fatty acids, and the like.

The aliphatic dicarboxylic acids include succinic acid, adipic acid, azelaic acid, and maleic acid; the alicyclic dicarboxylic acids include cyclohexanedicarboxylic acid; and the aromatic dicarboxylic acids include isophthalic acid and terephthalic acid. Can be mentioned.

Further, examples of the aliphatic monocarboxylic acid include acetic acid, stearic acid, oleic acid, linoleic acid and the like.

On the other hand, as the amine component, polyamines include aliphatic diamines such as ethylenediamine, propylenediamine and hexamethylenediamine; aliphatic polyamines such as diethylenetriamine and triethylenetetramine; and alicyclic diamines such as cyclohexylenediamine and isophoronediamine. , Aromatic diamines such as xylylenediamine, phenylenediamine, aromatic diamines such as diaminodiphenylmethane, as primary and secondary monoamines, butylamine, octylamine, mono- and di-alkylamines such as diethylamine, monoethanolamine, monoethanolamine Mono- and di-alkanolamines such as propanolamine, diethanolamine, dipropanolamine and the like can be mentioned.

Particularly, when only a polyamide resin is used as the binder resin for the ink, alkanolamine is used as a primary or secondary monoamine component in order to have reactivity with a crosslinking agent, and a hydroxyl value of about 0.5 to 10 is used. A polyamide resin having a hydroxyl group in the molecule is used. In this case, a polyamide resin containing no hydroxyl group may be used in combination.

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 / 0.0.
9, preferably 1.0 / 1.0 and a reaction temperature of 160
In the final stage, the reaction is desirably performed under a reduced pressure of about 100 torr at a temperature of from about 280 ° C., preferably from 180 to 230 ° C.

Cellulose Derivatives Cellulose derivatives that can be used as a binder resin of the ink composition of the present invention include nitrocellulose as a nitro group-substituted product, and lower alkyl such as cellulose acetate and cellulose acetate propionate as a lower acyl-substituted product. Examples of the group-substituted product include methyl cellulose and ethyl cellulose.

As to the molecular weight and the degree of substitution of hydroxyl groups of these cellulose derivatives, those in the range used in ordinary paints and ink compositions can be used without any problem in the present invention, but the degree of substitution of hydroxyl groups is 1.3 to 2 .7 is preferable, and a nitro group-substituted product is advantageous from the viewpoint of heat resistance, and a lower acyl group-substituted product and a lower alkyl group-substituted product are advantageous from the viewpoint of adhesiveness. It is preferable to select and use them appropriately according to the purpose.

In the present invention, the amount of the polyamide resin-based binder resin used is usually preferably in the range of 5 to 30% by weight in the ink composition from the viewpoint of viscosity and fluidity. When a polyamide resin-cellulose derivative binder resin is used, the total amount of the binder resin is usually about 5 to 30% by weight in the ink composition from the viewpoint of viscosity and fluidity. The ratio is 1.0 / 0.1 to 1.0 / 1.0 in terms of gloss and heat resistance.
A range of 0.5 (weight ratio) is preferred. In the case of a polyamide resin-cellulose derivative-based binder resin,
A polyamide resin that does not contain a hydroxyl group can also be used.

Polyurethane Resin Polyurethane resin which can be used as a binder resin of the ink composition of the present invention synthesizes a urethane prepolymer by reacting an organic diisocyanate compound and a high molecular weight diol compound, and comprises a chain extender and a reaction terminator. It is a polyurethane resin obtained by the reaction.

First, organic diisocyanate compounds include aromatic diisocyanate compounds such as tolylene diisocyanate, alicyclic diisocyanate compounds such as 1,4-cyclohexane diisocyanate and isophorone diisocyanate, aliphatic diisocyanate compounds such as hexamethylene diisocyanate, and the like. α, α, α ',
Aromatic aliphatic diisocyanate compounds such as α'-tetramethylxylylene diisocyanate are exemplified.

These organic diisocyanate compounds are
They can be used alone or as a mixture, but from the viewpoints of solubility and fluidity of the ink, alicyclic, aliphatic or araliphatic ones are preferred.

As the polymer diol compound, various polymer diol compounds can be used in addition to the polyether diol compound and the polyester diol compound.

Here, examples of the polyether diol compound include polyalkylene glycols such as polyethylene glycol and polypropylene glycol, and alkylene oxide adducts such as ethylene oxide and propylene oxide of bisphenol A.

As the polyester diol compound, dibasic acids such as adipic acid, sebacic acid and phthalic anhydride, ethylene glycol, propylene glycol,
1,4-butanediol, neopentyl glycol, 3
And those obtained by subjecting a glycol such as -methyl-1,5-pentanediol to a condensation reaction.

Further, examples of other high molecular diol compounds include polycaprolactone diol, polycarbonate diol, polybutadiene diol and the like.

As these high molecular weight diols, those having a number average molecular weight of 300 to 6000 are preferable. The polymer diols can be used alone or as a mixture, but polyester diol compounds are more preferable in view of the lamination strength of the obtained lamination ink and the suitability for boiling and retorting.

The use ratio of the organic diisocyanate compound to the polymer diol compound is such that the equivalent ratio of the isocyanate group to the hydroxyl group is usually (1.3 to 3.0): 1.
0, more preferably (1.5-2.0): 1.0.

Next, as the chain extender, first, a diamino alcohol compound such as aminoethylethanolamine for introducing a hydroxyl group into the polyurethane molecule, two primary hydroxyl groups such as glycerin and one secondary hydroxyl group are used. Or more polyalcohol compounds can be used.

When a hydroxyl group is introduced into a molecule by a reaction terminator described later, a diol compound or a diamine compound can be used.

Here, examples of the diol compound include ethylene glycol, propylene glycol, 1,4-butanediol, neopentyl glycol, 1,6-hexanediol and the like. Examples of the diamine compound include ethylenediamine, propylene Diamine, hexamethylenediamine, α, α, α ′, α′-tetramethylxylylenediamine, isophoronediamine and the like can be mentioned.

As the reaction terminator, a compound having both a hydroxyl group and a functional group which reacts with an isocyanate group, such as monoethanolamine and diethanolamine, for introducing a hydroxyl group into the polyurethane molecule can be used. A monoamine compound such as monobutylamine or a monoalcohol compound such as methanol or ethanol can be used in combination with 0.5 equivalent or less of the residual isocyanate group before the termination of the reaction.

When a hydroxyl group is introduced into the molecule by using a chain extender, monoamine or monoalcohol can be used alone.

As a method for producing a polyurethane resin from each of the above-mentioned materials, a known method for producing a polyurethane resin for an ink binder can be used as it is.

It is preferred to introduce a hydroxyl group into the polyurethane resin by the above method, and to use a polyurethane resin having a hydroxyl value of about 0.5 to 30.

The number average molecular weight of the polyurethane resin is usually from 5,000 to 150,000, more preferably from 30,000 to 100,000.

In the present invention, the usual use amount of the polyurethane resin binder is preferably in the range of 5 to 30% by weight in the ink composition from the viewpoint of viscosity and fluidity.

Other binder resins As other binder resins, various binder resins used in solvent-type printing inks for films can be used.
Specific examples include a maleic acid resin, an acrylic resin, a polyester resin, a terpene resin, a petroleum resin, a ketone resin, and the like. The amount of these binder resins used in the ink composition is usually about 0 to 10% by weight.

<Titanium-Based Crosslinking Agent> The titanium-based crosslinking agent usable in the present invention comprises at least one of the titanate compounds represented by the following general formula (1) (component (a)) and the general formula (2): It is a reaction product obtained by reacting at least one kind (component (b)) of the represented di (polyoxyethylene alkyl ether) phosphate.

[0053]

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Here, X is each independently 3 carbon atoms.
To 18 alkyl groups or acyl groups, and Y each independently represents an alkyl group having 1 to 18 carbon atoms. Also, j is an integer from 0 to 9, m and n are positive integers, and m + n = 2
Meet 10.

When the number of carbon atoms of the alkyl group and the acyl group of X in the molecular structure represented by the general formula (1) exceeds 18, the oil resistance of the obtained printing ink is reduced, while the number of carbon atoms is smaller than 3. The heat resistance of the resulting printing ink is undesirably reduced. Further, when j exceeds 9, the heat resistance of the obtained printing ink is reduced.

The alkyl group having 3 to 18 carbon atoms represented by X includes, for example, n-propyl, isopropyl, n
-Butyl, isobutyl, sec-butyl, tert-butyl, n-hexyl, n-octyl, 2-ethylhexyl, decyl, dodecyl, tetradecyl, octadecyl and the like. Examples of the acyl group having 3 to 18 carbon atoms represented by X include propionyl, butyryl, hexanoyl,
Octanoyl, decanoyl, lauroyl, tetradecanoyl, stearoyl and the like can be mentioned.

From the viewpoint of improving the heat resistance of the obtained printing ink, the printing ink contains an acyl group having 8 to 18 carbon atoms such as octanoyl, decanoyl, lauroyl, tetradecanoyl, stearoyl or the like in an amount equal to or more than the number of titanium atoms in the molecule. Titanate compounds are preferred.

Specific examples of the component a include tetraisopropoxytitanium, tetra-n-butoxytitanium, tetrakis (2-ethylhexyloxy) titanium, tetrastearyloxytitanium, triisopropoxytitanium monostearate, and tri-n-butoxytitanium. Titanium monostearate, diisopropoxytitanium distearate, di-n-
Butoxytitanium distearate, bis (2-ethylhexyloxy) titanium distearate and its 2-10 (j
= 1 to 9). These titanate compounds can be used alone or in combination of two or more.

From the viewpoint of the heat resistance of the ink, as the titanate compound, a titanium stearate compound having a stearoyl group together with an alkyl group as the group represented by X in the general formula (1) can be more preferably used.

In the molecular structure represented by the general formula (2), the hydroxyl group is a reaction point for the compound represented by the general formula (1) and is necessary for obtaining the effects of the present invention.
When the number of these groups is two or more, the storage stability of the ink composition decreases. Compounds having an alkyl group represented by Y having more than 18 carbon atoms are difficult to produce and are not suitable for use. Further, when the value of m + n is less than 2, the storage stability is lowered, and when it exceeds 10, the heat resistance of the printing ink, which is considered to be more than 10, is lowered.

Examples of the alkyl group having 1 to 18 carbon atoms represented by Y include methyl, ethyl, propyl, butyl, pentyl, hexyl, octyl, dodecyl, octadecyl and the like.

As a specific example of the component b, di [POE
(2) propyl ether] phosphoric acid, di [POE (2) butyl ether] phosphoric acid, di [POE (4) propyl ether] phosphoric acid, di [POE (4) butyl ether] phosphoric acid, di [POE (4) hexyl ether] phosphoric acid, Di [POE
(4) Octyl ether] phosphoric acid, di [POE (4) dodecyl ether] phosphoric acid, di [POE (4) octadecyl ether] phosphoric acid, di [POE (6) propyl ether] phosphoric acid, di [POE (6) butyl ether] phosphoric acid , Di [PO
E (8) propyl ether] phosphoric acid, di [POE (8) butyl ether] phosphoric acid, di [POE (10) propyl ether] phosphoric acid, di [POE (10) butyl ether] phosphoric acid, and the like. These di (polyoxyethylene alkyl ether) phosphates can be used alone or
A mixture of more than one species can be used. In the above description, PO
E indicates polyoxyethylene, and the number in parentheses indicates the number of moles added.

Further, the reaction ratio between the component a and the component b is a
Component: b component = (0.5 to 4): a ratio (molar ratio) of 1: 1. When the amount of the a component is less than the above range, the heat resistance of the ink is reduced, and when it is increased, the storage stability of the ink is reduced. It is not preferable because it decreases.

The reaction between the component a and the component b is usually carried out by dissolving each component in an organic solvent such as an alcohol-based solvent or a ketone-based solvent, and cooling the solution to room temperature or below. Can be carried out while gradually mixing the component b solution dropwise.

The content of the titanium-based crosslinking agent obtained as described above is 0.1 to 5% by weight based on the entire printing ink composition. If the content of the titanium-based crosslinking agent is less than the above range, sufficient heat resistance and oil resistance cannot be obtained, and if the content is too large, the storage stability of the ink decreases.

<Organic solvent> The organic solvent used in the present invention includes aromatic hydrocarbons such as toluene and xylene;
Ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone; esters such as methyl acetate, ethyl acetate, propyl acetate and butyl acetate; alcohols such as methanol, ethanol and propanol; and glycols such as ethylene glycol and propylene glycol and the like Examples thereof include various organic solvents such as derivatives, which are usually used as a mixed solvent.

<Method for Producing Ink> As a method for producing the ink composition of the present invention using the above-mentioned materials, a mixture of a binder resin, a pigment, an organic solvent and, if necessary, a pigment dispersant is mixed with a high-speed mixer. In general, the meat is ground using a ball mill, a sand mill, an attritor, or the like, and the rest of a predetermined material is added and mixed.

<Use> The ink composition of the present invention can be mainly used for printing on various adherends by using a gravure printing method.

Here, the adherend on which the ink composition is printed is a polyester film such as a normal oriented polypropylene (OPP) film, a non-oriented polypropylene (CPP) film, a modified polypropylene film, a polyethylene terephthalate (PET) film and the like. In addition to various plastic films such as nylon, polystyrene, etc., stretched polypropylene (VM-OPP) films, metal-unstretched polypropylene (VM-CPP) films, polyethylene terephthalate (VM-PET) films, etc., on which metals such as aluminum are deposited, respectively. Is raised.

Further, in a system using a polyurethane resin as an ink binder, after printing on the above-mentioned film, an imine-based, isocyanate-based, polybutadiene-based, titanium-based, etc. anchor coating agent is applied to the printed surface and melted. It is also applicable to extrusion lamination processing for laminating polyolefin and dry lamination processing for coating a plastic film by applying an adhesive such as urethane on the printed surface.

The printing ink composition of the present invention exerts an excellent effect not only on ordinary plastic films but also on metal-deposited films, which is not provided by conventional ink compositions.

[0072]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited thereto.
Parts and% represent parts by weight and% by weight, respectively, unless otherwise specified.

<Preparation of Titanium Crosslinking Agent> The titanate compound and di (polyoxyethylene alkyl ether) phosphate used in the following production examples are as follows.

[0074]

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[0075]

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[0076]

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[0077]

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Production Example 1 677 parts of a 75% isopropanol solution of compound T1 was charged into a reactor equipped with a stirrer, a cooling pipe and a dropping funnel, and the reactor was cooled in a cooling bath to keep the internal temperature at 5 to 10 ° C. Then, 355 parts of a 75% isopropanol solution of the compound P1 was gradually dropped through a dropping funnel, and the mixture was reacted by stirring and mixing. 1 was obtained.

Production Examples 2 to 19 In the same manner as in Production Example 1, the titanium-based crosslinking agent 2-19 were obtained.

[0080]

[Table 1]

<Preparation of Polyamide Resin Varnish> In a mixed solvent of 280 parts of toluene, 280 parts of methyl ethyl ketone, and 140 parts of isopropanol, 300 parts of a commercially available polyamide resin (Romeide S2600, manufactured by Kao Corporation) was dissolved to obtain a solid content of 30%. A polyamide (PA) resin varnish was obtained.

<Preparation of Cellulose Derivative Varnish> Nitrogenated cotton HIG1 was used as nitrocellulose in 850 parts of ethyl acetate.
/ 2 (manufactured by Asahi Kasei Corporation) was dissolved to obtain a cellulose derivative (CN) varnish having a solid content of 15%.

<Preparation of Polyurethane Resin Varnish> In the same apparatus as in Synthesis Example 1, isophorone diisocyanate was used.
1 part, 207 parts of polybutylene adipate diol having a number average molecular weight of 2,000 synthesized from adipic acid and 1,4-butanediol were charged, and 10 parts were introduced while introducing nitrogen gas.
The reaction was performed at 0 ° C. for 10 hours. After cooling, toluene 193
And 193 parts of methyl ethyl ketone were added and uniformly dissolved. 193 parts of isopropyl alcohol and 11.9 parts of isophoronediamine were added and reacted for 20 minutes. The reaction was further stopped with 1.3 parts of monoethanolamine, and the number average molecular weight was 25,000. Thus, a polyurethane (PU) resin varnish having a solid content of 30% was obtained.

Examples 1 to 20 and Comparative Examples 1 to 16 According to the formulations in Tables 2 and 3, a pigment, an appropriate amount of a resin component and a mixed solvent were charged, kneaded with a Red Devil type paint conditioner for 30 minutes, and the remaining components were further kneaded. By adding and mixing, ink compositions of Examples 1 to 20 and Comparative Examples 1 to 16 were prepared.

The pigment used was titanium oxide (Typek R-900, manufactured by DuPont). Further, a mixed solvent having a composition of toluene / methyl ethyl ketone / isopropyl alcohol = 40/40/20 weight ratio was used.

<Evaluation Tests> The ink compositions of Examples 1 to 20 and Comparative Examples 1 to 16 were evaluated for oil resistance, heat resistance, adhesion, and viscosity stability over time according to the following evaluation methods. The results are shown in Figs.

The ink composition using the polyamide resin / cellulose derivative is used particularly in the field where heat resistance and oil resistance are required for OPP film use, and the ink composition using the polyurethane resin is used for various plastic films. It is used in fields where heat resistance and oil resistance are not required. Then, the performance required for each ink was evaluated.

(Adhesion) Evaluation Method Each test ink containing a polyamide resin / cellulose derivative was printed on an OPP film with a gravure proofer and dried with warm air to obtain a printed product. In addition, each test ink containing polyurethane resin was OPP
Printing was performed on a film, a PET film, and an aluminum-deposited PET film, followed by drying with hot air to obtain a printed material. In the case of an aluminum-evaporated PET film, printing was performed on the aluminum-evaporated surface.
A cellophane tape was stuck to the printed surface of these printed materials, and the adhesiveness was evaluated from the degree to which the printed film peeled off the film when rapidly peeled off.

Evaluation Criteria A: The printed film does not peel off from the film at all. B: Less than 20% of the area of the printed film is peeled off from the film. C: 20% or more and less than 50% of the area ratio of the printed film is peeled off from the film. D: 50% or more of the printed film is separated from the film as an area ratio.

(Heat resistance) Evaluation method Heat seal provided with a hot plate having a heat gradient of 80 to 160 ° C. on the printing surface obtained by printing each test ink containing a polyamide resin / cellulose derivative on an OPP film using a gravure proofer. The aluminum foil was used for 1.
It was pressed at a pressure of 6 kg / cm ² for 2 seconds. The heat resistance of the test ink was evaluated from the lowest temperature at which the ink on the printing surface was transferred to the aluminum foil.

[0091]

(Oil resistance) Evaluation method Each test ink containing a polyamide resin / cellulose derivative was printed on an OPP film with a gravure proofer, and the printed surface was soaked with salad oil using a Gakushin type friction tester. The cloth was rubbed 100 times under a load of 500 g, and the oil resistance was evaluated from the change in the printed surface.

Evaluation Criteria A: There is no change on both the printing surface and the address cloth. B: The printed surface is not changed, but the cloth to be applied is colored. C: Streaky scratches are observed on the printed surface. D: Surface scratches are observed on the printed surface.

(Evaluation Method of Viscosity Stability over Time) Viscosity change of test ink before and after aging at 40 ° C. for 7 days (3 in B-type viscometer).
The viscosity stability over time was evaluated from ink viscosity measurement data at 0 rpm).

Evaluation criteria A: Viscosity ratio after aging / before aging is less than 1.5 B: Viscosity ratio after aging / before aging is 1.5 or more and less than 2.0 C: After aging / before aging The viscosity ratio before and after 2.0 is less than 3.0 and D: the viscosity ratio after and after aging is 3.0 or more.

Here, adhesiveness, oil resistance and viscosity stability over time are practically acceptable if they are at least rank B and heat resistance is at least rank C.

The plastic film used was:
OPP film (Pyrene P-2161, thickness 30μ,
Toyobo Co., Ltd.), PET film (E-510)
2, film thickness 12μ, manufactured by Toyobo Co., Ltd.), VM-PET
Film (VM-PET E-7075, manufactured by Toyobo Co., Ltd.).

[0098]

[Table 2]

[0099]

[Table 3]

[0100]

As described above, the printing ink composition of the present invention has excellent adhesiveness, heat resistance, and oil resistance for use in front and back printing of plastic films. It is a solvent-type printing ink composition having good storage stability and good storage stability over time.

Claims (3)

[Claims] 1. A printing ink composition mainly comprising a pigment, a hydroxyl group-containing resin, a titanium-based cross-linking agent and an organic solvent, wherein the titanium-based cross-linking agent is a titanate compound represented by the following general formula (1): At least one kind (component (a)) and at least one kind of di (polyoxyethylene alkyl ether) phosphate represented by the general formula (2) (component (b)) have a molar ratio of component (a): component (0). 5-4) A printing ink composition, which is a reaction product reacted at a ratio of 1: 1 and contained in a range of 0.1 to 5% by weight of the total composition of the printing ink. Embedded image Here, X independently represents an alkyl group or an acyl group having 3 to 18 carbon atoms, and Y independently represents an alkyl group having 1 to 18 carbon atoms. In addition, j is an integer of 0 to 9, m and n are positive integers, and satisfies m + n = 2 to 10. 2. A polyamide resin and / or a cellulose derivative is used as the hydroxyl group-containing resin.
The printing ink composition according to the above. 3. The printing ink composition according to claim 1, wherein a polyurethane resin is used as the hydroxyl group-containing resin.