JP2022182772A - Printing ink composition for shrink packaging, method for manufacturing printed matter for shrink packaging, and printed matter for shrink packaging - Google Patents

Abstract

To provide a printing ink composition for shrink packaging which is excellent in content resistance suitability (surfactant resistance and alkali resistance) even when a biomass degree is set to be high, and has good other performances.SOLUTION: A printing ink composition for shrink packaging contains a pigment, a resin component and a solvent component, and contains a carboxyl group-containing acrylic resin, a cellulose resin, a rosin resin and a derivative thereof satisfying the following conditions 1 and 2 as resin components. Condition 1: A ratio of a solid content mass of the carboxyl group-containing acrylic resin to a solid content mass of the cellulose resin is 80/20 to 60/40. Condition 2: The rosin resin and the derivative thereof have acid values of 150 mgKOH/g or less, and are contained in an amount of 3.0-20.0 mass% in the solid content of the ink composition.SELECTED DRAWING: None

Description

TECHNICAL FIELD The present invention relates to a printing ink composition for shrink packaging, a method for producing a printed matter for shrink packaging, and a printed matter for shrink packaging.

Paper containers, steel cans, aluminum cans, glass containers, plastic containers, and the like are used as various containers in the fields of beverages, cosmetics, detergents, etc., taking advantage of their respective characteristics.
Various types of printing are applied to the surfaces of these containers to indicate the contents. Among the various containers described above, in the case of a paper container, the printing efficiency is extremely high because the paper container is shaped after the necessary printing is performed in the form of a sheet or roll of paper.
However, in the case of other containers, since they are molded in a special shape in advance, the usual printing method cannot be applied. Therefore, it was printed directly on the molded container by pasting a label printed matter, printing by a screen method, transferring the ink on the intaglio plate surface to an elastic body, or using a special printing method for cans. . However, these methods are extremely poor in work efficiency or are not suitable for high-mix low-volume production.
Therefore, a heat-shrinkable film is used as the material to be printed, and after printing on this, the printed material is made into a cylinder, and after covering the cylinder with the container, it is mounted on the surface by heat shrinking to make a package, so-called shrink. packaging is used. In general, in the printing of shrink packaging, a binder resin (for example, Patent Documents 1 and 2) and a gravure printing ink composition for shrink packaging using a binder resin (for example, Patent Document 3) in which an acrylic resin and a cellulose resin are used in combination are used.
However, in recent years, due to environmental concerns, inks with a high degree of biomass are also required for gravure printing ink compositions for shrink packaging. In particular, in applications where surfactant resistance and alkali resistance are required, there is a limit to the use of cellulose-based components, and it has been difficult to increase the degree of biomass. Furthermore, with white ink, the content ratio of pigments such as titanium oxide in the solid content is high, and the acrylic resin used as the binder resin is a petroleum-derived resin, making it more difficult to increase the degree of biomass.
In addition, among products that use shrink packaging, especially when using containers for household detergents, shampoos, body soaps, alkaline detergents, etc., the contents may adhere to the surface of the container after the start of use. In that case, it is also necessary to have resistance to the contents so as not to damage the printing.

JP 2004-175858 A JP 2009-286974 A Japanese Patent No. 6732151

An object of the present invention is to provide a printing ink composition for shrink packaging that has excellent resistance to contents (surfactant resistance, alkali resistance) and other properties even when the biomass content is high. do.

The present inventors have made intensive studies to solve the above problems, and as a result, have completed the present invention described below.
That is, the present invention is as follows.
1. A printing ink composition for shrink packaging containing a pigment, a resin component and a solvent component, wherein the resin component contains a carboxyl group-containing acrylic resin, a cellulose resin, a rosin resin and derivatives thereof that satisfy the following conditions 1 and 2. A printing ink composition for shrink packaging.
Condition 1:
The ratio of the solid mass of the carboxyl group-containing acrylic resin to the solid mass of the cellulose resin is solid mass of the carboxyl group-containing acrylic resin/solid mass of the cellulose resin = 80/20 to 60/40.
Condition 2:
The rosin resin and its derivative have an acid value of 150 mgKOH/g or less, and are contained in the solid content of the ink composition in an amount of 3.0 to 20.0% by mass.
2. 2. The printing ink composition for shrink packaging according to 1, wherein the carboxyl group-containing acrylic resin has an acid value of 2 to 20 mgKOH/g and a mass average content of 30,000 to 100,000.
3. 3. The printing ink composition for shrink packaging according to 1 or 2, wherein the cellulose resin is a cellulose acetate propionate resin and a cellulose acetate butyrate resin.
4. 4. The printing ink composition for shrink packaging according to any one of 1 to 3, wherein the rosin resin and its derivative have an acid value of 30 mgKOH/g or less.
5. Any one of 1 to 4, wherein the solvent component contains an alcohol-based solvent and an ester-based solvent, and the mass ratio of the alcohol-based solvent to the ester-based solvent is alcohol-based solvent/ester-based solvent = 60/40 to 80/20. The printing ink composition for shrink packaging according to 1.
6. 6. The printing ink composition for shrink packaging according to any one of 1 to 5, which contains a plasticizer.
7. 7. The printing ink composition for shrink packaging according to 6, wherein the plasticizer is an epoxidized vegetable oil.
8. 8. The printing ink composition for shrink packaging according to any one of 1 to 7, wherein the pigment is a white pigment.
9. 9. The printing ink composition for shrink packaging according to 8, wherein the white pigment is rutile-type titanium oxide having a treated layer made of silica and/or alumina.
10. A method for producing a printed material for shrink packaging, comprising printing the printing ink composition for shrink packaging according to any one of 1 to 9 on a shrinkable film.
11. A print for shrink packaging obtained by printing the printing ink composition for shrink packaging according to any one of 1 to 9 on a shrinkable film.

According to the present invention, it is possible to increase the biomass degree even when the ink composition, particularly the white ink composition, has a high pigment content, and furthermore, the content resistance suitability (surfactant resistance, alkali resistance) is also improved. It is possible to obtain an excellent printing ink composition for shrink packaging (the printed part is not damaged when the contents of the container, such as soap and toiletries, adhere to the printed surface).

The present invention relates to a printing ink composition for shrink packaging containing a pigment, a resin component and a solvent component, wherein the resin component is a carboxyl group-containing acrylic resin, a cellulose resin, a rosin resin and their A printing ink composition for shrink packaging comprising a derivative.
Condition 1:
The ratio of the solid mass of the carboxyl group-containing acrylic resin to the solid mass of the cellulose resin is solid mass of the carboxyl group-containing acrylic resin/solid mass of the cellulose resin = 80/20 to 60/40.
Condition 2:
The rosin resin and its derivative have an acid value of 150 mgKOH/g or less, and are contained in a range of 1 to 6% by mass in the solid content of the resin.
The printing ink composition for shrink packaging of the present invention will be specifically described below.
The biomass degree of the printing ink composition for shrink packaging of the present invention is preferably 10 or more. The biomass degree is calculated by the following formula.
Degree of biomass = amount of biomass component / total solid content including pigment in printing ink composition for shrink packaging × 100
Biomass component: Total amount of biomass-derived weight in resin solid content and additive solid content (resin weight x biomass weight ratio + additive weight x biomass weight ratio)

<Acid value>
The acid value in the present invention is obtained by calculating the theoretical neutralization amount of potassium hydroxide (KOH) with respect to the amount of each monomer theoretically required to obtain 1 g of carboxyl group-containing acrylic resin, rosin resin, etc. , and the total amount in mg of the neutralized amount is defined as the acid value of the polymer.

<Mass average molecular weight>
The mass average molecular weight of the resin in the invention can be measured by a gel permeation chromatography (GPC) method. As an example, using Water2690 (manufactured by Waters) as a GPC apparatus, PLgel, 5μ, MIXED-D (manufactured by Polymer Laboratories) as a column, tetrahydrofuran as a developing solvent, column temperature 25 ° C., flow rate 1 ml / min, RI Chromatography is performed under the conditions of a detector, a sample injection concentration of 10 mg/ml, and an injection amount of 100 microliters.

<Pigment>
As the pigment, various inorganic pigments and organic pigments commonly used in printing inks can be used. Specifically, inorganic pigments such as titanium oxide, red iron oxide, antimony red, cadmium yellow, cobalt blue, Prussian blue, and ultramarine blue can be used. , carbon black, graphite and other colored pigments, calcium carbonate, kaolin, clay, barium sulfate, aluminum hydroxide, talc and other extender pigments. Furthermore, examples of organic pigments include soluble azo pigments, insoluble azo pigments, azo lake pigments, condensed azo pigments, copper phthalocyanine pigments, and condensed polycyclic pigments. White pigments such as titanium oxide, rutile-type titanium oxide with a treated layer of silica and/or alumina, and other colored pigments may also be used. The pigment content is 1 to 50% by weight relative to the total weight of the printing ink composition for shrink packaging. The present invention is useful for titanium oxide, which is an inorganic pigment.

<Resin component>
As a resin component, it contains a carboxyl group-containing acrylic resin, a cellulose resin, a rosin resin and derivatives thereof.
(Carboxyl group-containing acrylic resin)
Carboxyl group-containing acrylic resins include copolymers of radically polymerizable carboxylic acid monomers and radically polymerizable acrylic monomers, and radically polymerizable carboxylic acid monomers other than radically polymerizable acrylic monomers. and a copolymer that also contains a radically polymerizable monomer.
Examples of the radically polymerizable carboxylic acid monomers include acrylic acid, methacrylic acid, crotonic acid; monoesters and monoamides of dicarboxylic acids such as maleic acid, fumaric acid, citraconic acid and itaconic acid; maleic anhydride, citraconic anhydride, itaconic anhydride; esters of vinyl alcohol and saturated carboxylic acids having 2 to 18 carbon atoms such as acetic acid, propionic acid, lauric acid and stearic acid;
Radically polymerizable acrylic monomers include alcohol esters such as methyl, ethyl, propyl, butyl and pentyl alcohol of acrylic acid and methacrylic acid, and diesters such as ethylene glycol and propylene glycol. Examples of the radically polymerizable monomer (c) other than the radically polymerizable carboxylic acid monomer and the radically polymerizable acrylic monomer include styrene and α-methylstyrene.
Among these carboxyl group-containing acrylic resins, copolymers in which the carboxyl group is derived from a methacrylic acid monomer are preferable, and further methacrylic acid (MAA), methyl methacrylate (MMA) and butyl methacrylate (BMA) ) is preferred.

The acid value of the carboxyl group-containing acrylic resin obtained by copolymerizing the above monomers is preferably 2 to 20 mgKOH/g. Moreover, it is more preferably 3 mgKOH/g or more, more preferably 15 mgKOH/g or less, and even more preferably 10 mgKOH/g or less. If it is less than 2 mgKOH/g, problems with compatibility with cellulose resin tend to occur, and if it is more than 20 mgKOH/g, content resistance suitability (surfactant resistance, alkali resistance) tends to be inferior.
Further, the weight average molecular weight of the carboxyl group-containing acrylic resin is preferably 30,000 to 100,000. Among them, 35,000 or more is more preferable, and 40,000 or more is even more preferable. Moreover, 90,000 or less is more preferable, and 80,000 or less is still more preferable.
If the weight-average molecular weight is less than 30,000, blocking properties, adhesiveness, etc. tend to decrease, while if it exceeds 100,000, the solubility and solubility with cellulose resin tend to decrease.
The content of the carboxyl group-containing acrylic resin in the solid content of the printing ink composition for shrink packaging of the present invention is preferably 10.0% by mass or more, more preferably 13.0% by mass or more, and 14.0% by mass. The above is more preferable. Moreover, 40.0 mass % or less is preferable, 35.0 mass % or less is more preferable, and 30.0 mass % or less is further more preferable.

(cellulose resin)
As the cellulose resin, cellulose acetate propionate resin, cellulose acetate butyrate resin, nitrocellulose resin, etc., which are conventionally used in gravure inks, can be used. Cellulose acetate propionate resin and cellulose acetate butyrate resin are preferable from the viewpoint of improving surfactant resistance, alkali resistance, and the like.
The cellulose resin in the printing ink composition for shrink packaging of the present invention satisfies Condition 1 below.
The ratio of the solid mass of the carboxyl group-containing acrylic resin to the solid mass of the cellulose resin in the printing ink composition for shrink packaging is: solid mass of carboxyl group-containing acrylic resin/solid mass of cellulose resin=80/ 20 to 60/40. And 75/25 to 65/35 is preferable. When the solid content mass ratio of the cellulose resin is more than 40, content resistance suitability (surfactant resistance, alkali resistance) tends to decrease, while when it is less than 20, blocking property etc. tends to decrease. .
The total content of each cellulose resin in the solid content of the printing ink composition for shrink packaging of the present invention is preferably 3.0% by mass or more, more preferably 5.0% by mass or more, and 7.0% by mass. % or more is more preferable. Moreover, it is preferably 20.0% by mass or less, more preferably 15.0% by mass or less, and even more preferably 11.0% by mass or less.

(cellulose acetate propionate resin)
As the cellulose acetate propionate resin, known cellulose acetate propionate resins conventionally used in gravure printing ink compositions can be used.
Cellulose acetate propionate resin is obtained by hydrolyzing after tri-esterifying cellulose with acetic acid and propionic acid. In general, the cellulose acetate propionate resin has an acetyl group content of 0.6 to 2.5% by weight, a propionate group content of 42.0 to 46.0% by weight, and a hydroxyl group content of 1.8 to 5.5% by weight. Resins with 0% by weight are commercially available. Among these, it is preferable to use a low-molecular-weight resin in order to improve the degree of biomass.
The content of the cellulose acetate propionate resin in the solid content of the printing ink composition for shrink packaging of the present invention is preferably 3.0% by mass or more, more preferably 5.0% by mass or more, and 7.0% by mass. % or more is more preferable. Moreover, it is preferably 20.0% by mass or less, more preferably 15.0% by mass or less, and even more preferably 11.0% by mass or less.

(cellulose acetate butyrate resin)
As the cellulose acetate propionate resin, resins conventionally used in gravure printing ink compositions can be used. Cellulose acetate butyrate resin is obtained by hydrolyzing after tri-esterifying cellulose with acetic acid and butyric acid. In general, resins containing 2 to 30% by weight of acetylation, 17 to 53% by weight of butyrylation, and 1 to 5% of hydroxyl groups are commercially available. Among these, it is preferable to use a low-molecular-weight resin in order to improve the degree of biomass.
The content of the cellulose acetate butyrate resin in the solid content of the printing ink composition for shrink packaging of the present invention is preferably 3.0% by mass or more, more preferably 5.0% by mass or more, and 7.0% by mass. The above is more preferable. Moreover, it is preferably 20.0% by mass or less, more preferably 15.0% by mass or less, and even more preferably 11.0% by mass or less.

(nitrocellulose resin)
As the nitrocellulose resin, nitrocellulose resins conventionally used in gravure printing ink compositions can be used. The nitrocellulose resin is obtained as a nitrate ester obtained by reacting natural cellulose with nitric acid to replace three hydroxyl groups in the 6-membered ring of the anhydride glucopyranose group in the natural cellulose with nitric acid groups. As the nitrocellulose resin used in the present invention, one having a nitrogen content of 10 to 13% and an average degree of polymerization of 35 to 90 is preferably used. Specific examples include SS1/2, SS1/4, SS1/8, TR1/16, NCRS-2 (manufactured by KOREA CNC LTD), and the like.
The content of the nitrocellulose resin in the solid content of the printing ink composition for shrink packaging of the present invention is preferably 3.0% by mass or more, more preferably 5.0% by mass or more, and 7.0% by mass or more. More preferred. Moreover, it is preferably 20.0% by mass or less, more preferably 15.0% by mass or less, and even more preferably 11.0% by mass or less.

(Rosin resin and its derivative)
Rosin resins include gum rosin, tall oil rosin, wood rosin and the like. Generally, rosin is an amber colored, amorphous resin obtained from pine trees, which is a mixture of abietic acid, neoabietic acid, parastric acid, pimaric acid, isopimaric acid, sandaracopimaric acid, Dehydroabietic acid may be isolated and used for each constituent component, and these are also defined as rosin resins in the present invention.
Rosin resin derivatives are compounds obtained by modifying the above rosin resins, and are specifically listed below.
(1) Hydrogenated rosin: Rosin with improved weather resistance by adding hydrogen to conjugated double bonds (hydrogenation).
(2) Disproportionated rosin: Disproportionation is the reaction of two molecules of rosin to form two molecules of abietic acid with conjugated double bonds, one of which is aromatic and the other is a single double bond. It is a degeneration that becomes a molecule. It is generally less weather resistant than hydrogenated rosin, but more weather resistant than untreated rosin.
(3) Rosin-modified phenolic resin: A rosin-modified phenolic resin is often used as the main binder for offset printing inks. A rosin-modified phenolic resin can be obtained by a known production method.
(4) Rosin ester: An ester resin derived from rosin, which has long been used as a tackifier for adhesives.
(5) Rosin-modified maleic acid resin: A resin obtained by subjecting rosin to an addition reaction with maleic anhydride, and optionally grafting a hydroxyl group-containing compound such as glycerin with an acid anhydride group through esterification.
(6) Polymerized rosin: a derivative containing dimerized resin acids derived from the natural resin rosin.
In addition, known rosin and rosin derivatives can also be used, and these can be used alone or in combination.
The rosin resin in the printing ink composition for shrink packaging of the present invention satisfies the following condition 2:.
The acid value of the rosin resin and its derivatives is 150 mgKOH/g or less. If it exceeds 150 mgKOH/g, the stability of the ink composition and suitability for content resistance (alkali resistance and surfactant resistance) are lowered. From the standpoint of excellent content suitability, it is preferably 100 mgKOH/g or less, more preferably 50 mgKOH/g or less, more preferably 30 mgKOH/g or less, extremely preferably 20 mgKOH/g or less, and most preferably 10 mgKOH/g or less.
The content of the rosin resin and its derivative in the solid content of the printing ink composition for shrink packaging of the present invention is 3.0 to 20.0% by mass. And 5.0 mass % or more is preferable, and 7.0 mass % or more is more preferable. Moreover, 15.0 mass % or less is preferable and 10.0 mass % or less is more preferable.

(Other resins)
In the printing ink composition for shrink packaging of the present invention, as a resin component other than the carboxyl group-containing acrylic resin, cellulose resin, rosin resin and derivatives thereof, within the range not impairing the effects of the present invention, Other resins may be used together.
Other resins include polyurethane urea resins, polyurethane resins, vinyl chloride-vinyl acetate copolymer resins, polyamide resins, acrylic resins, ethylene-vinyl acetate copolymer resins, chlorinated olefin resins, alkyd resins, vinyl acetate resins, Examples include ketone resins, polybutyral resins, cyclized rubber resins, chlorinated rubber resins, petroleum resins, olefin resins, polyester resins, and polylactic acid resins.
An acrylic resin having a phosphoric acid group may or may not be included.

(Plasticizer)
As a plasticizer, dioctyl sebacate, fatty acid triglyceride, ethyltoluenesulfonic acid amide, acetyl tributyl citrate, stearic acid 2-ethylhexyl ester, palmitic acid 2-ethylhexyl ester, etc., and epoxidized vegetable oil, which have been used in gravure printing inks, are used as plasticizers. Available. Among these, epoxidized vegetable oils such as epoxidized soybean oil and epoxidized linseed oil are preferred from the viewpoint of content resistance suitability (surfactant resistance, alkali resistance) and biomass content.
The content of the plasticizer is not particularly limited. For example, the content of the plasticizer in the printing ink composition for shrink packaging is preferably 0.05% by mass or more, more preferably 0.5% by mass or more, and preferably 5.0% by mass or less. , 3.0% by mass or less. When the content of the plasticizer is within the above range, the obtained print ink composition for shrink packaging is improved in contents resistance suitability (surfactant resistance, alkali resistance).

(Amide compound)
Furthermore, the printing ink composition for shrink packaging includes an amide compound from the viewpoint of further improving scratch resistance, adhesion to substrates, scratch resistance, and content resistance suitability (surfactant resistance and alkali resistance). is preferably contained. Examples of the amide compound include palmitic acid amide, stearic acid amide, ethylenebisoleic acid amide, hexamethylenebisoleic acid amide, and the like, and these may be used alone or in combination of two or more. good too. When an amide compound is added, it is preferably contained in the printing ink composition for shrink packaging in an amount of 0.1 to 5.0% by mass. Among them, in order to achieve both scratch resistance, adhesion to substrates, scratch resistance, surfactant resistance and alkali resistance, it is preferable to contain 0.1 to 4.0% by mass, and 0.3 to 2 It is preferably contained at 0.5% by mass.

(Solvent component)
Solvent components used in the printing ink composition for shrink packaging of the present invention include alcohol solvents such as methanol, ethanol, isopropanol, normal propanol, butanol, isobutanol and tert-butanol, and aromatic hydrocarbons such as toluene and xylene. aliphatic hydrocarbon solvents such as hexane, cyclohexane, methylcyclohexane, and ethylcyclohexane; ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ethyl acetate, n-propyl acetate, isopropyl acetate, butyl acetate; Ester solvents such as isobutyl acetate, sec-butyl acetate, tert-butyl acetate, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol dimethyl ether, ethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene Glycol-based solvents such as glycol monopropyl ether and propylene glycol monobutyl ether and esters thereof can be mentioned, and the esters are mainly acetates, such as ethylene glycol monomethyl ether acetate and ethylene glycol monoethyl ether acetate. , ethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate and the like. These can be used alone or in combination of two or more.
Among these solvent components, it is preferable to use an alcohol-based solvent and/or an ester-based solvent from an environmental point of view, and more preferably an alcohol-based solvent and/or an ester-based solvent having 1 to 4 carbon atoms. Furthermore, it is preferable that the weight ratio of alcohol-based solvent and ester-based solvent having 1 to 4 carbon atoms is alcohol-based/ester-based solvent = 60/40 to 80/20, 63/37 to 75/25. It is preferable to use so as to be If the ester-based solvent is more than 40, there is a possibility of attacking the shrinkable OPS (shrinkable untreated polystyrene film). Also, if the ester solvent is less than 20%, the solubility of the resin component tends to decrease.

(Other ingredients)
In addition, the printing ink composition for shrink packaging of the present invention may optionally contain a friction-resistant agent, an antiblocking agent, a pigment dispersant, an antistatic agent, a lubricant, a cross-linking agent, an antifoaming agent, and a drying control agent. agents, other plasticizers, tackifiers, adhesion improvers, leveling agents, antioxidants and the like can be added. Among them, biomass-derived additives are more desirable.
Examples of lubricants include polyethylene (PE) wax, polypropylene wax, PTFE wax, paraffin wax, microcrystalline wax, Fischer-Tropsch wax, montan wax, carnauba wax, shellac wax, amide wax, organic polymers, beeswax, and mixed waxes thereof. and the like are preferable, and among them, polyethylene wax and polypropylene wax are more preferable.

(Method for producing the printing ink composition for shrink packaging of the present invention)
Next, an example of the method for producing the ink composition described above will be described. In the method for producing a printing ink composition for shrink packaging according to the present embodiment, a pigment, a binder resin, an organic solvent, and optionally optional components (pigment dispersant, surfactant, etc.) are stirred and mixed, and then various pastes are mixed. A method of kneading using a machine such as a bead mill, ball mill, sand mill, attritor, roll mill, pearl mill, etc., and then adding and mixing the rest of the materials such as predetermined additives is exemplified.

(Printed matter for shrink packaging)
Next, a printed matter for shrink packaging (hereinafter also simply referred to as printed matter) according to one embodiment of the present invention will be described. The printed matter of the present invention is a printed matter in which the ink composition described above is printed on a shrinkable film as a substrate. The printed matter is preferably obtained by printing the ink composition on a shrinkable film or the like as a substrate by using a gravure printing machine or a flexographic printing machine. As the printing conditions, known conditions are appropriately adopted. The printed matter may be dried after printing in order to scatter the organic solvent in the ink. As the drying conditions, known conditions are appropriately adopted.
The shrinkable film is preferably a shrinkable polypropylene film, a shrinkable polyvinyl chloride film, a shrinkable polyethylene phthalate film, or a shrinkable polystyrene film (especially a shrinkable untreated polystyrene film) obtained by stretching treatment or the like. .
The resulting printed material is used for various shrink packaging applications such as shrink labels and wrap film printed materials. When used as a shrink label, the printed material is tubed by means of fusion sealing or the like, attached to a PET container or a glass container, etc., and then heated to a predetermined shrinking temperature to be thermally shrunk and brought into close contact with the container. be done. When used for wrap film prints, the prints are used for wrapping odd-shaped articles, bundling merchandise, and guaranteeing packaging.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to Examples. The present invention is by no means limited to these examples. Unless otherwise specified, "%" means "% by mass" and "parts" means "parts by mass" (values in the table are parts by mass).
The raw materials used and their preparation methods are shown below.
(Carboxyl group-containing acrylic resin)
Carboxyl group-containing acrylic resin 1: MAA/MMA/BMA
Theoretical acid value 3 mgKOH/g, mass average molecular weight 60,000
Carboxyl group-containing acrylic resin 2: MAA/MMA/BMA
Theoretical acid value 7 mgKOH/g, mass average molecular weight 60,000
Carboxyl group-containing acrylic resin 3: MAA/MMA/BMA
Theoretical acid value 13 mgKOH/g, mass average molecular weight 60,000
Carboxyl group-containing acrylic resin 4: MAA/MMA/BMA
Theoretical acid value 3 mgKOH/g, mass average molecular weight 40,000
Carboxyl group-containing acrylic resin 5: MAA/MMA/BMA
Theoretical acid value 3 mgKOH/g, mass average molecular weight 80,000

(Phosphate group-containing acrylic resin)
Phosphate group-containing acrylic resin solution Conventional method containing 0.01 wt% (meth)acrylic acid ester having a phosphate group, 35 wt% methyl methacrylate, and 64.99 wt% butyl methacrylate in 100 wt% resin A 40% solids solution of a resin synthesized by Isopropyl alcohol/Ethyl acetate = 4/6 mixed solvent. The resin had a weight average molecular weight of 60,000 and an acid value of 0.1 mgKOH/g.

(pigment)
Titanium oxide: Rutile-type titanium oxide pigment surface-treated with silica alumina Pigment Blue 15:4 (PB15:4)

(cellulose resin)
Cellulose acetate butyrate (CAB-381-0.5, manufactured by Eastman, number average molecular weight 30,000)
Cellulose acetate butyrate (CAB-381-0.1, manufactured by Eastman, number average molecular weight 20,000)
Cellulose acetate propionate (CAP-482-0.5, manufactured by Eastman, number average molecular weight 25,000)
Nitrocellulose: (LIG1/8, manufactured by SNP Japan)

(Rosin resin and its derivative)
Rosin ester (acid value 7 mgKOH/g)
Rosin ester (acid value 15 mgKOH/g)
Maleic acid-modified rosin resin (acid value 40 mgKOH/g)
Dimerized rosin (140 mg KOH/g)
Maleic acid-modified rosin resin (acid value 300 mgKOH/g)

(Plasticizer)
Epoxidized soybean oil Epoxidized linseed oil Dioctyl sebacate

(Amide compound)
stearamide
(PE wax)
Spray 30 (manufactured by Sasol)
(Antifoaming agent)
BYK-094 (manufactured by BYK)

<Printing White Ink Compositions for Shrink Packaging of Examples 1 to 18 and Comparative Examples 2 to 5>
45 parts by mass of a pigment (titanium oxide), 9 parts by mass of a carboxyl group-containing acrylic resin (7.5 parts by mass in the case of Comparative Example 6), 10 parts by mass of isopropyl alcohol, and 15 parts by mass of ethyl acetate were mixed using a paint conditioner. After kneading, a carboxyl group-containing acrylic resin, a rosin resin, a plasticizer, the remaining materials and a solvent were added and mixed so as to have the composition shown in Table 1 to prepare a printing white ink composition for shrink packaging.
<Examples 19 to 28 Printing Color Ink Compositions for Shrink Packaging>
10 parts by mass of a color pigment other than white, 9 parts by mass of a carboxyl group-containing acrylic resin, 10 parts by mass of isopropyl alcohol, and 15 parts by mass of ethyl acetate are kneaded using a paint conditioner, and the carboxyl A group-containing acrylic resin, rosin resin, cellulose resin, plasticizer, remaining materials and solvent were added and mixed to prepare a printing color ink composition for shrink packaging.
<Printing white ink composition for shrink packaging of Comparative Example 1>
45 parts by mass of a pigment (titanium oxide), 22.5 parts by mass of a phosphoric acid group-containing acrylic resin solution, 6.9 parts by mass of isopropyl alcohol, and 4.6 parts by mass of ethyl acetate were kneaded using a paint conditioner. A phosphoric acid group-containing acrylic resin solution, a rosin resin, a cellulose resin, a plasticizer, the remaining materials and a solvent were added and mixed so as to obtain a composition of , to prepare a printing white ink composition for shrink packaging.

<Print method>
The printing ink compositions for shrink packaging of Examples 1 to 28 and Comparative Examples 1 to 6 were mixed with a mixed solvent (isopropyl alcohol: ethyl acetate = 6:4 mixed solvent).
These diluted compositions were applied to a shrinkable untreated polystyrene film (BS-55S, thickness 50 μm, manufactured by Takiron C.I. Co., Ltd.) was printed at a printing speed of 150 m/min to obtain each print. All the printed matter to be evaluated other than the anti-blocking property was obtained by this method.

<Printing evaluation>
(Adhesiveness)
A cellophane tape (registered trademark) was affixed to the printed surface of each of the above printed materials, and the degree of peeling of the printed film from the film when rapidly peeled off was evaluated according to the following evaluation criteria.
<Evaluation Criteria>
◯: Not peeled off at all.
Δ: Slightly partly peeled, but practically acceptable.
x: Mostly peeled off or completely peeled off.

(Scratch resistance)
Each of the above prints was strongly rubbed with the back of a nail, and evaluation was made by observing ink drop-off.
<Evaluation Criteria>
◯: There was no damage at all.
Δ: Partially peeled off.
x: Mostly peeled off or completely peeled off.

(Kneading resistance)
The state of cracks in the coating film of each printed material was evaluated according to the following evaluation criteria after each printed material was strongly rubbed with both hands 10 times.
<Evaluation Criteria>
◯: Not cracked at all.
Δ: Partially cracked.
x: Cracked as a whole. scratch resistance

(residual solvent)
The amount of residual solvent in each of the above prints was measured according to the method of the Flexible Packaging Sanitation Council, and evaluated according to the following evaluation criteria.
<Evaluation Criteria>
○: The amount of residual solvent was less than 5 mg/m ² .
Δ: The amount of residual solvent was 5 to 15 mg/m ² .
x: The amount of residual solvent was more than 15 mg/ ^m2 .

(Original fabric attack resistance)
The degree of crack generation in each of the above prints was visually evaluated. Evaluation criteria for resistance to attack on the original fabric are shown below.
<Evaluation Criteria>
◯: No cracks occurred in the printed matter.
Δ: Slight cracks are observed in the printed matter.
x: Significant cracks are observed in the printed matter, or the printed matter is completely torn.

(Blocking resistance)
The printing ink compositions for shrink packaging of Examples 1 to 28 and Comparative Examples 1 to 6 were spread with a Mere bar having a wire diameter of 0.1 mm, and then dried with hot air to obtain each print. The ink-printed surface and the non-printed surface of the printed matter were put together and left under a load of 29.4×10 ⁴ Pa (3 kg/cm ² ) at 40° C. for 24 hours. The degree of peeling of the film was evaluated. Evaluation criteria for blocking resistance are shown below.
<Evaluation Criteria>
Good: No peeling of the ink and no resistance to peeling.
Δ: Slight peeling of ink, and peeling resistance is felt.
x: Most of the ink is peeled off, and peeling resistance is felt strongly.

(edge crack)
Each of the above prints was wrapped around a glass bottle with the film sandwiched therebetween, and immersed in hot water at 90° C. for 10 seconds. After drying, the degree of cracking at the edges was evaluated.
<Evaluation Criteria>
◯: There was no cracking of the ink.
Δ: There was partial cracking of the ink.
x: Cracking of the ink was observed on the whole.

<Content resistance>
Each of the above printed matter was immersed in the following contents and left at 40° C. for 24 hours. After allowing to stand, the content was washed off with water, and the degree of ink dropout was evaluated.
Body soap (Naive (registered trademark) body soap manufactured by Kracie Holdings Co., Ltd.)
Hand soap (Naive (registered trademark) hand soap manufactured by Kracie Holdings Co., Ltd.)
Kitchen Haiter (manufactured by Kao Corporation)
<Evaluation Criteria>
◯: There was no dropout of the ink.
Δ: There was a slight drop of ink.
x: The ink was completely removed.

According to each example, in addition to being able to achieve a sufficiently high degree of biomass, it has excellent adhesiveness, scratch resistance, rubbing resistance, original fabric attack resistance, blocking resistance, and content resistance, and has no residual solvent. The effect of less can be achieved.
However, Comparative Example 1 containing no carboxyl group-containing acrylic resin but containing a phosphoric acid group-containing acrylic resin, Comparative Example 2 in which the acid value of the rosin resin was too high, and Comparative Example 4 in which the content of the rosin resin was too high. According to the results, the contents resistance was inferior.
Further, according to Comparative Example 3, in which the content of rosin resin is small, a sufficiently high degree of biomass could not be achieved.
According to Comparative Example 5, in which the carboxyl group-containing acrylic resin is excessive in the ratio of the solid content mass of the carboxyl group-containing acrylic resin to the solid content mass of the cellulose resin, the more important blocking resistance is insufficient. According to Comparative Example 6, in which the carboxyl group-containing acrylic resin was too small, there was, more importantly, insufficient adhesion and residual solvent.

Claims (11)

A printing ink composition for shrink packaging containing a pigment, a resin component and a solvent component,
A printing ink composition for shrink packaging containing, as a resin component, a carboxyl group-containing acrylic resin, a cellulose resin, a rosin resin and derivatives thereof, satisfying the following conditions 1 and 2.
Condition 1:
The ratio of the solid mass of the carboxyl group-containing acrylic resin to the solid mass of the cellulose resin is solid mass of the carboxyl group-containing acrylic resin/solid mass of the cellulose resin = 80/20 to 60/40.
Condition 2:
The rosin resin and its derivative have an acid value of 150 mgKOH/g or less, and are contained in the solid content of the ink composition in an amount of 3.0 to 20.0% by mass. 2. The printing ink composition for shrink packaging according to claim 1, wherein the carboxyl group-containing acrylic resin has an acid value of 2 to 20 mgKOH/g and a weight average content of 30,000 to 100,000. The printing ink composition for shrink packaging according to claim 1 or 2, wherein the cellulose resin is a cellulose acetate propionate resin or a cellulose acetate butyrate resin. The printing ink composition for shrink packaging according to any one of claims 1 to 3, wherein the rosin resin and its derivative have an acid value of 30 mgKOH/g or less. Claims 1 to 4, wherein the solvent component contains an alcohol-based solvent and an ester-based solvent, and the mass ratio of the alcohol-based solvent to the ester-based solvent is alcohol-based solvent/ester-based solvent = 60/40 to 80/20. The printing ink composition for shrink packaging according to any one of the above. The printing ink composition for shrink packaging according to any one of claims 1 to 5, which contains a plasticizer. 7. The printing ink composition for shrink packaging according to claim 6, wherein the plasticizer is an epoxidized vegetable oil. The printing ink composition for shrink packaging according to any one of claims 1 to 7, wherein the pigment is a white pigment. 9. The printing ink composition for shrink packaging according to claim 8, wherein the white pigment is rutile-type titanium oxide having a treated layer of silica and/or alumina. A method for producing a printed material for shrink packaging, comprising printing the printing ink composition for shrink packaging according to any one of claims 1 to 9 on a shrinkable film. A print for shrink packaging obtained by printing the printing ink composition for shrink packaging according to any one of claims 1 to 9 on a shrinkable film.