JP2023112955A - Ink composition and printed material - Google Patents

Abstract

To provide an ink composition that can form a printed layer having excellent rub resistance, adhesion to a substrate, and a glossy feeling, the ink composition capable of suppressing the occurrence of doctor streaks even when used in gravure printing.SOLUTION: An ink composition contains a binder resin, a hydrocarbon wax, and an organic solvent. The binder resin contains a polyamide resin and nitrocellulose. The nitrocellulose has a nitrogen content of 11.5-12.2 mass%, the nitrocellulose has a viscosity index of 1/16-2, and the hydrocarbon wax has a penetration of 9.5 or more.SELECTED DRAWING: None

Description

The present invention relates to ink compositions and printed matter.

BACKGROUND ART When a packaging material is produced using a base material such as a plastic film, printing with a printing ink such as gravure ink is performed for decoration and surface protection of the base material. Gravure printing is suitable for mass production because it enables high-definition and high-speed printing. However, from the viewpoint of improving the working environment, etc., there is a demand for the development of non-toluene-based solvent inks that do not contain toluene. In addition, there is a demand for an ink capable of printing high-quality images in order to respond to the diversification of packaging materials and the sophistication of packaging technology.

The properties required for inks such as gravure inks used for printing on film substrates include the printability of the ink itself, such as resistance to doctor streaks, as well as the abrasion resistance and abrasion resistance of the printed layer formed by the ink. Coating properties such as adhesion to the substrate are important. Further, in recent years, there is a tendency to demand a printing layer excellent in gloss in order to improve the appearance of printed matter.

For the purpose of improving the film properties of the printed layer formed, for example, a gravure ink for surface printing containing a binder resin, wax, chlorinated polyolefin, and fatty acid amide has been proposed (Patent Document 1). Also, a gravure printing ink for lamination has been proposed that contains a binder resin, chlorinated polypropylene, polyethylene wax, and fatty acid amide (Patent Document 2). Furthermore, a gravure ink for forming a printed layer between two substrates has been proposed, which contains a binder resin, a chlorinated polyolefin resin, and a fatty acid amide (Patent Document 3).

JP 2006-299136 A JP 2020-70396 A JP 2018-184584 A

However, even with the gravure inks and the like proposed in Patent Documents 1 to 3, when the ink on the plate is scraped off with a doctor blade, white streaks (so-called doctor streaks) are formed along the direction of rotation on the plate. ) could not necessarily be sufficiently suppressed. In addition, the abrasion resistance, adhesion to the substrate, and glossiness of the ink layer to be formed are not necessarily sufficient, and there is room for further improvement.

The present invention has been made in view of the problems of the prior art, and its object is to form a printed layer having excellent abrasion resistance, adhesion to the substrate, and glossiness. The object of the present invention is to provide an ink composition capable of suppressing the generation of doctor streaks even when used for gravure printing. Another object of the present invention is to provide a printed material using this ink composition.

That is, according to the present invention, the following ink composition is provided.
[1] contains a binder resin, a hydrocarbon wax, and an organic solvent, the binder resin contains a polyamide resin and nitrocellulose, and the nitrogen content of the nitrocellulose is 11.5 to 12.2% by mass; An ink composition wherein the nitrocellulose has a viscosity symbol of 1/16 to 2 and the hydrocarbon wax has a penetration of 9.5 or more.
[2] The ink composition according to [1], wherein the mass ratio of the polyamide resin (P) and the nitrocellulose (N) is P:N=50:50 to 90:10.
[3] The ink composition according to the above [1] or [2], further containing a chlorinated polyolefin resin.
[4] The ink according to any one of [1] to [3], wherein the content of the hydrocarbon wax is 0.5 to 2.0% by mass based on the solid content in the ink composition. Composition.

Moreover, according to this invention, the printed matter shown below is provided.
[5] A printed matter comprising a substrate and a printed layer formed of the ink composition according to any one of [1] to [4], which is disposed on the surface of the substrate.

According to the present invention, it is possible to form a printed layer having excellent abrasion resistance, adhesion to a substrate, and glossiness, and to suppress generation of doctor streaks even when used for gravure printing. A possible ink composition can be provided. Further, according to the present invention, printed matter using this ink composition can be provided.

Embodiments of the present invention will be described below, but the present invention is not limited to the following embodiments. An ink composition (hereinafter also simply referred to as "ink") which is one embodiment of the present invention is an ink for surface printing used for gravure printing, for example, containing a binder resin, a hydrocarbon wax, and an organic solvent. It is an ink composition suitable as Details of the ink composition of the present embodiment will be described below.

(binder resin)
A binder resin is a component that functions as a binder resin for forming a printed layer (image) formed by ink applied to a substrate. The binder resin used in the ink composition of the present embodiment contains polyamide resin and nitrocellulose. The binder resin is preferably substantially composed of polyamide resin and nitrocellulose. By using a polyamide resin and nitrocellulose in combination, it is possible to improve the abrasion resistance, adhesion to the base material, and glossiness of the printed layer to be formed. The content of the binder resin in the ink composition may generally be about 20 to 95% by mass based on the solid content in the ink composition, and may be appropriately set according to the application.

As the polyamide resin, a thermoplastic polyamide resin soluble in an organic solvent, which is obtained by polycondensation of a polybasic acid and a polyvalent amine, is usually used. Polybasic acids include adipic acid, sebacic acid, azelaic acid, phthalic anhydride, isophthalic acid, suberic acid, glutaric acid, fumaric acid, pimelic acid, oxalic acid, malonic acid, succinic acid, maleic acid, terephthalic acid, 1 , 4-cyclohexyldicarboxylic acid, trimellitic acid, dimer acid, hydrogenated dimer acid, polymerized fatty acid, and the like.

As polyvalent amines, aliphatic diamines, aliphatic polyamines, alicyclic polyamines, aromatic polyamines, and the like can be used. Examples of aliphatic diamines include ethylenediamine, propylenediamine, hexamethylenediamine, methylaminopropylamine, and the like. Examples of aliphatic polyamines include diethylenetriamine and triethylenetetramine. Cyclohexylene diamine, isophorone diamine, etc. can be mentioned as an alicyclic polyamine. Examples of aromatic polyamines include xylylenediamine, phenylenediamine, diaminodiphenylmethane, and the like.

From the viewpoint of solubility of the polyamide resin, the weight average molecular weight is preferably 2,000 to 50,000, more preferably 3,000 to 10,000. When the weight average molecular weight of the polyamide resin is within the above range, the abrasion resistance of the formed printed layer can be further improved. The content of the polyamide resin in the ink composition is preferably 5 to 60% by mass, more preferably 15 to 45% by mass, based on the solid content in the ink composition.

The acid value of the polyamide resin is preferably 30 mgKOH/g or less, more preferably 15 mgKOH/g or less. Also, the amine value of the polyamide resin is preferably 30 mgKOH/g or less, more preferably 15 mgKOH/g or less.

Nitrocellulose (nitrocellulose) is usually a nitric acid ester obtained by reacting natural cellulose with nitric acid, in which three hydroxyl groups in natural cellulose are substituted with nitric acid groups. The nitrogen content of nitrocellulose, which is blended as a binder resin in the ink composition of the present embodiment, is 11.5 to 12.2% by mass. By using nitrocellulose having a nitrogen content within the above range as the binder resin, an ink composition capable of forming a printing layer having excellent abrasion resistance can be obtained.

Further, the viscosity symbol of nitrocellulose is 1/16 to 2, preferably 1/8 to 1, more preferably 1/4 to 1. By using nitrocellulose with a viscosity symbol within the above range as a binder resin, it is possible to form a printing layer with a glossy feel and excellent abrasion resistance, and when applied to gravure printing, doctor streaks do not occur. It can be an ink composition that is difficult to If the nitrocellulose has a viscosity symbol of more than 2, the resulting printed layer will have reduced glossiness and abrasion resistance, and doctor streaks will tend to occur when applied to gravure printing. The viscosity symbol of nitrocellulose is a physical property value at 25° C. specified in JIS K 6703:1995. The content of nitrocellulose in the ink composition is preferably 1 to 40% by mass, more preferably 2 to 30% by mass, more preferably 3 to 25% by mass, based on the solid content in the ink composition. %, most preferably 8 to 15% by weight.

The mass ratio of polyamide resin (P) and nitrocellulose (N) in the ink composition is preferably P:N = 50:50 to 90:10, more preferably 60:40 to 80:20. preferable. By setting the mass ratio of the polyamide resin (P) to the nitrocellulose (N) within the above range, it is possible to further improve the friction resistance of the printed layer formed and the adhesion to the substrate.

(hydrocarbon wax)
The ink composition contains a hydrocarbon wax having a penetration (hardness) at 25°C defined in JIS K 2207 of 9.5 or more, preferably 10 or more, more preferably 12 or more, and particularly preferably 15 or more. . By containing a hydrocarbon wax whose penetration is within the above range, the abrasion resistance of the formed printed layer (ink film) is further improved. In addition, since the particles are dispersed more finely, glossiness is less likely to be impaired, and doctor streaks are less likely to occur when applied to gravure printing, thereby improving printability.

Hydrocarbon waxes include polyethylene wax, Fischer-Tropsch wax, paraffin wax, microstaline wax, polypropylene wax and the like. Among them, polyethylene wax and Fischer-Tropsch wax are preferred. The content of the hydrocarbon wax in the ink composition is preferably 0.5 to 2.0% by mass, more preferably 0.7 to 1.7% by mass, based on the solid content in the ink composition. is more preferred.

Examples of polyethylene wax include high-density polymerized polyethylene, low-density polymerized polyethylene, oxidized polyethylene, acid-modified polyethylene, special monomer-modified polyethylene, and the like. Fischer-Tropsch wax is a wax produced by the Fischer-Tropsch process using carbon monoxide and hydrogen as raw materials, and has a nearly saturated linear molecular structure without branching.

(chlorinated polyolefin resin)
The ink composition preferably further contains a chlorinated polyolefin resin. A chlorinated polyolefin resin is a component that can function as a tackifier. Therefore, by including the chlorinated polyolefin resin, the adhesion of the printed layer formed from the ink composition to various substrates can be further improved.

The content of the chlorinated polyolefin resin in the ink composition is preferably 1 to 50 parts by mass, more preferably 5 to 45 parts by mass, more preferably 7.5 to 7.5 parts by mass, based on 100 parts by mass of the binder resin. 40 parts by mass is particularly preferable, and 10 to 30 parts by mass is most preferable. By setting the content of the chlorinated polyolefin resin within the above range, the adhesion of the printed layer to various substrates can be further enhanced.

A chlorinated polyolefin resin is a polyolefin resin in which at least part of hydrogen atoms are substituted with chlorine atoms. The chlorinated polyolefin preferably has a weight average molecular weight of 5,000 to 100,000 because it has good compatibility with the binder resin and good affinity with the hydrocarbon wax. A chlorine content of 25 to 45% by mass in the chlorinated polyolefin resin is preferable because the adhesion of the printed layer to the substrate is further improved. The chlorine content of the chlorinated polyolefin resin is the content of chlorine atoms (% by mass) in the chlorinated polyolefin resin.

As the polyolefin resin constituting the chlorinated polyolefin resin, homopolymers or copolymers of α-olefin unsaturated hydrocarbons such as polypropylene, poly-1-butene and poly-4-methyl-1-pentene are preferable. Polypropylene is more preferred. That is, chlorinated polypropylene is preferable as the chlorinated polyolefin resin. By using chlorinated polypropylene and hydrocarbon wax together, the adhesion of the printed layer to various substrates can be synergistically improved.

(Fatty acid amide)
The ink composition preferably further contains a fatty acid amide. By containing the fatty acid amide, the blocking resistance of the printed layer formed can be improved. As fatty acid amides, those having an aliphatic hydrocarbon group having 10 to 25 carbon atoms and an amide group are preferred. Specific examples of fatty acid amides include lauric acid amide, palmitic acid amide, stearic acid amide, behenic acid amide, hydroxystearic acid amide, oleic acid amide, and erucic acid amide. The content of the fatty acid amide in the ink composition is preferably 0.1 to 10% by mass, more preferably 0.5 to 5% by mass, based on the solid content in the ink composition.

(solvent)
The ink composition contains an organic solvent. Examples of organic solvents include aromatic organic solvents such as toluene and xylene; aliphatic hydrocarbon organic solvents such as cyclohexane and methylcyclohexane; ketone organic solvents such as methyl ethyl ketone and methyl isobutyl ketone; ester organic solvents such as isopropyl acetate and isobutyl acetate; alcohol organic solvents such as methanol, ethanol, n-propanol, isopropanol and n-butanol; glycol ether solvents such as ethylene glycol monopropyl ether and propylene glycol monomethyl ether; can be used.

Among them, an organic solvent (non-toluene organic solvent) that does not substantially contain an aromatic organic solvent such as toluene or xylene is preferable. That is, the ink composition is preferably a non-toluene ink that does not substantially contain toluene from an environmental point of view. The organic solvent preferably includes an aliphatic hydrocarbon-based organic solvent, an ester-based organic solvent, and an alcohol-based organic solvent. The content of the aliphatic hydrocarbon-based organic solvent in the organic solvent is preferably 30 to 80% by mass based on the total organic solvent. The content of the ester-based organic solvent in the organic solvent is preferably 1 to 50% by mass based on the total organic solvent. The content of the alcohol-based organic solvent in the organic solvent is preferably 1 to 50% by mass based on the total organic solvent.

(pigment)
The ink composition may contain a pigment. A colorless ink composition that does not substantially contain a coloring material such as a pigment may be used.

As pigments, extender pigments, inorganic pigments, organic pigments, and the like can be used. Examples of extender pigments include silica, barium sulfate, kaolin, clay, calcium carbonate and magnesium carbonate. Inorganic pigments include white inorganic pigments such as titanium oxide, zinc oxide, zinc sulfide, barium sulfate, calcium carbonate, chromium oxide, and silica; black inorganic pigments such as carbon black and iron black; aluminum particles, mica, bronze powder, and chromium. Vermilion, yellow lead, cadmium yellow, cadmium red, ultramarine blue, Prussian blue, red iron oxide, yellow iron oxide, zinc oxide, and other inorganic pigments of various colors;

Examples of organic pigments include soluble azo, insoluble azo, azo, phthalocyanine, halogenated phthalocyanine, anthraquinone, anthanthrone, dianthraquinonyl, anthrapyrimidine, perylene, perinone, quinacridone, Examples include thioindigo-based, dioxazine-based, isoindolinone-based, quinophthalone-based, azomethineazo-based, flavanthrone-based, diketopyrrolopyrrole-based, isoindoline-based, and indanthrone-based organic pigments.

The content of the pigment in the ink composition may be set to an amount sufficient to ensure the coloring power and the like of the ink. Specifically, the content of the pigment in the ink composition may generally be 1 to 80% by mass based on the solid content in the ink composition.

(Additive)
The ink composition can further contain various additives. Additives include pigment derivatives, dispersants, plasticizers, wetting agents, adhesion aids, leveling agents, antifoaming agents, antistatic agents, viscosity modifiers, chelating agents, trapping agents, antiblocking agents, and the aforementioned hydrocarbons. Wax components other than wax, cross-linking agents, silane coupling agents, and the like can be used.

By including a chelating agent in the ink composition, it is possible to form a printed layer with further improved adhesion to plastic substrates and the like, and further improved abrasion resistance. As the chelating agent, it is preferable to use a titanium chelating agent. Titanium chelating agents include titanium alkoxides such as tetraisopropyl titanate, tetra-normal-butyl titanate, butyl titanate dimer, tetra(2-ethylhexyl) titanate, tetramethyl titanate, tetrastearyl titanate; triethanolamine titanate, titanium acetylacetate toner; titanium tetraacetylacetonate, tetraisopropoxytitanium, titanium ethylacetoacetate, titanium lactate, octylene glycol titanate, titanium n-butyl phosphate, propanediox titanium bis(ethylacetylacetate), and the like.

The content of the chelating agent in the ink composition is preferably 0.1 to 10% by mass, more preferably 0.5 to 5% by mass, based on the solid content in the ink composition. By setting the content of the chelating agent within the above range, the ink stability can be improved, and the abrasion resistance of the formed printed layer can be further enhanced.

(Production of ink composition)
The ink composition can be produced by a conventionally known method. For example, it can be produced by dissolving or dispersing a binder resin, hydrocarbon wax, or the like in a solvent. Physical properties such as viscosity of the ink composition can be adjusted by appropriately controlling the size and filling rate of the media used in the dispersing machine, the dispersion treatment time, and the like. The hydrocarbon wax is preferably finely dispersed in the solvent in advance and added during the manufacturing process. As a dispersing machine, a roller mill, ball mill, pebble mill, attritor, sand mill, or the like can be used.

<Printed Matter>
A printed matter, which is one embodiment of the present invention, comprises a substrate and a printed layer formed of the ink composition described above and disposed on the surface of the substrate. The printed matter of the present embodiment can be produced, for example, by printing the ink composition on a substrate and then removing volatile components to form a printed layer. Examples of printing methods include gravure printing and flexographic printing. Especially, it is preferable to print by gravure printing. After diluting the ink composition with a diluting solvent so that it has a viscosity and concentration suitable for gravure printing, it is supplied to a printing unit of a gravure printing machine and applied onto a substrate such as a plastic film. After that, by drying in an oven or the like to form a printed layer (film) and fixing it, a printed matter that is a laminate can be obtained.

A film-like or sheet-like base material can be used as the base material. As the substrate, paper or plastic substrates (films and sheets) can be used. Examples of plastics constituting the base material include polyolefin resins such as polyethylene and polypropylene; polyester resins such as polyethylene terephthalate, polycarbonate, and polylactic acid; polystyrene resins such as polystyrene, AS resin, and ABS resin; polyamide resins; vinylidene chloride; cellophane; and the like.

The plastic substrate may be corona treated or untreated. Also, the plastic substrate may be stretched or unstretched. Metals or metal oxides such as silica, alumina, and aluminum may be deposited on the plastic base material, and the deposition surface may be coated with a paint such as polyvinyl alcohol.

EXAMPLES The present invention will be specifically described below based on Examples, but the present invention is not limited to these Examples. "Parts" and "%" in Examples and Comparative Examples are based on mass unless otherwise specified.

<Preparation of each component>
Each component shown below was prepared.
(binder resin)
Polyamide A: weight average molecular weight 4000, acid value 7 mgKOH/g or less, amine value 7 mgKOH/g or less Polyamide B: weight average molecular weight 6,000, acid value less than 8 mgKOH/g, amine value less than 6 mgKOH/g Nitrocellulose A : Product name “RS1/2”, manufactured by Kimia, nitrogen content 11.5 to 12.2%, viscosity symbol 1/2
・Nitrate cotton B: Product name “RS1/4”, manufactured by Kimia, nitrogen content 11.5 to 12.2%, viscosity symbol 1/4
・Nitrate cotton C: Product name “RS1/16”, manufactured by Kimia, nitrogen content 11.5 to 12.2%, viscosity symbol 1/16
・Nitrate cotton D: Product name “RS2”, manufactured by Kimia, nitrogen content 11.5 to 12.2%, viscosity symbol 2
・Nitrated cotton E: Product name “RS20”, manufactured by Kimia, nitrogen content 11.5 to 12.2%, viscosity symbol 20

(hydrocarbon wax)
・Wax A: low-density polyethylene wax, trade name "Hi-Wax 110P", manufactured by Mitsui Chemicals, Inc., penetration 25
・Wax B: Oxidized polyethylene wax, trade name "High Wax 220MP", manufactured by Mitsui Chemicals, Inc., penetration 14
・Wax C: polyolefin wax dispersion, trade name "X-7019", manufactured by Gifu Cerrac Co., Ltd., penetration 13
・Wax D: low-density polyethylene wax, trade name "AC polyethylene 6A", manufactured by HoneyWell, penetration 4
- Wax E: Polyethylene wax, trade name "MPP620VF", manufactured by Micro Powders, penetration 1

(pigment)
・Carbon black: Product name “Mitsubishi Carbon Black MA100”, manufactured by Mitsubishi Chemical ・Titanium oxide: Product name “Titanics JR-600A”, manufactured by Tayca

(other ingredients)
・Fatty acid amide: stearic acid amide, trade name “Neutron S”, manufactured by Nippon Fine Chemical Co., Ltd. ・Chlorinated PO: chlorinated polyolefin, trade name “Superchron 360T”, manufactured by Nippon Paper Industries Co., Ltd. ・Titanium chelating agent: trade name “ Orgatics TC-115", manufactured by Matsumoto Fine Chemical Co., Ltd. ・Antifoaming agent: trade name "BYK-1751", manufactured by BYK Chemie Japan ・Organic solvent: methylcyclohexane (MCH) / normal propyl acetate (NPAC) / isopropyl alcohol (IPA ) = 5/3/2

<Preparation of ink composition>
(Example 1)
10 parts of polyamide A, 4 parts of nitrocellulose A, 0.3 parts of wax A, 10 parts of carbon black, 0.5 parts of fatty acid amide, 2 parts of chlorinated PO, 1 part of titanium chelating agent, 0.1 part of antifoaming agent, and 72 parts of organic solvent .1 parts were mixed and well dispersed using a paint shaker to give an ink composition (Example 1).

(Examples 2 to 26, Comparative Examples 1 to 10)
Ink compositions (Examples 2 to 26, Comparative Examples 1 to 10) were prepared in the same manner as in Example 1 above, except that the types and amounts of each component shown in Tables 1-1 to 1-3 were used. Obtained. The materials listed in Tables 1-1 to 1-3 all represent the compounding amounts in terms of solid content.

<Evaluation>
Each ink composition prepared is diluted with an organic solvent (MCH/NPAC/IPA = 5/3/2) so that the viscosity at 25°C is 15 seconds measured using a Zahn cup #3, and printed. prepared ink for A gravure printing machine equipped with a Helio 175 line/inch gravure engraving plate was used to apply the prepared ink for printing to each of the substrates shown below to produce prints.
・OPP: Biaxially oriented polypropylene (OPP) film with corona discharge treatment on one side, thickness 25 μm (ink is applied to the treated side)
・CPP: Non-axially oriented polypropylene (CPP) film with corona discharge treatment on one side, thickness 30 μm (ink is applied to the untreated side)

(Appearance of printed matter (gloss))
The gloss value of the printed matter (OPP) manufactured using a gloss meter (trade name “micro-TRI-gloss S”, manufactured by BYK) is measured at a 60° angle, and the appearance of the printed matter is evaluated according to the following evaluation criteria. evaluated. Table 2 shows the results.
5: The gloss value was 70 or more.
4: The gloss value was 60 or more and less than 70.
3: The gloss value was 50 or more and less than 60.
2: The gloss value was 40 or more and less than 50.
1: The gloss value was less than 40.

(Adhesion)
A cellophane tape (trade name “Cellotape (registered trademark)”, manufactured by Nichiban Co., Ltd., width 12 mm) is attached to the printed surface of the manufactured printed matter, and then an adhesion test is performed to peel it off. The adhesion of the printed layer to was evaluated. Table 2 shows the results.
5: No ink film was removed on the cellophane tape side.
4: An area ratio of 1% or more and less than 5% of the ink coating film was removed on the cellophane tape side.
3: 5% or more and less than 20% of the ink coating was removed on the cellophane tape side in terms of area ratio.
2: 20% or more and less than 50% of the ink coating was removed on the cellophane tape side in terms of area ratio.
1: 50% or more of the ink coating was removed on the cellophane tape side in terms of area ratio.

(friction resistance)
Using a Gakushin type abrasion tester, the printed surface of the produced printed material was rubbed with Kanawa No. 3 100 times (200 g load). The surface of Kanawa No. 3 after rubbing was visually observed, and the abrasion resistance of the printed layer was evaluated according to the evaluation criteria shown below. Table 2 shows the results.
5: No removal of the ink film on the Kanawa No. 3 side.
4: 1% or more and less than 10% of the ink coating film was removed on the Kanawa No. 3 side in terms of area ratio.
3: 10% or more and less than 20% of the ink film was removed on the Kanawa No. 3 side in terms of area ratio.
2: 20% or more and less than 50% of the ink film was removed on the Kanawa No. 3 side in terms of area ratio.
1: 50% or more of the ink film was removed on the Kanawa No. 3 side in terms of area ratio.

(Printing suitability (Doctor's muscle))
Using a gravure printing machine, after 60 minutes of idle rotation of the plate at 150 m/min, doctor streaks were visually observed, and printability was evaluated according to the evaluation criteria shown below. As the doctor blade, a commercial product made of steel was used. Table 2 shows the results.
5: There is no doctor's muscle, or there are about 1 to 2 thin doctor's muscles.
4: There were about 3 to 5 thin doctor streaks.
3: There were 6 or more thin doctor's streaks, or about 1 to 2 thick doctor's streaks.
2: About 3 to 5 thick doctor's streaks were observed.
1: There were 6 or more dark doctor streaks.

The ink composition of the present invention is suitable as an ink for printing on plastic substrates (sheets, films), especially as a gravure ink for surface printing.

Claims (5)

containing a binder resin, a hydrocarbon wax, and an organic solvent,
The binder resin contains a polyamide resin and nitrocellulose,
The nitrogen content of the nitrocellulose is 11.5 to 12.2% by mass,
The viscosity symbol of the nitrocellulose is 1/16 to 2,
The ink composition, wherein the hydrocarbon wax has a penetration of 9.5 or more. 2. The ink composition according to claim 1, wherein the mass ratio of said polyamide resin (P) and said nitrocellulose (N) is P:N=50:50 to 90:10. 3. The ink composition according to claim 1, further comprising a chlorinated polyolefin resin. The ink composition according to any one of claims 1 to 3, wherein the content of the hydrocarbon wax is 0.5 to 2.0 mass% based on the solid content in the ink composition. A printed matter comprising a substrate and a printed layer formed of the ink composition according to any one of Claims 1 to 4 and disposed on the surface of the substrate.