JP2006111689A - Printing ink composition, laminate using the same and bottle container to which the laminate is attached - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a printing ink composition which can impart scratch resistance/stain resistance to a thermally shrinkable polyolefin film without shrinking and whitening the film, when printed on the film, to provide a laminate prepared by printing a film with the printing ink, and to provide a bottle container to which the laminate is attached. <P>SOLUTION: This printing ink composition contains one or more solvents selected from the group consisting of an alcohol-based solvent, a ketone-based solvent and an ester-based solvent without containing an aromatic hydrocarbon-based solvent, an aliphatic hydrocarbon-based solvent and an alicyclic hydrocarbon-based solvent. The laminate is obtained by printing a thermally shrinkable polyolefin film with the printing ink composition. The printing ink composition preferably contains polyvinyl acetal resin as a resin binder. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a printing ink composition for a heat-shrinkable polyolefin film used for a label or the like of a bottle container. The present invention also relates to a laminate on which the printing ink is printed and a bottle container to which the laminate is attached.

  A glass bottle, a plastic bottle container represented by polyethylene terephthalate (PET), or the like is often used as a container for filling food and drink such as juice and tea. A printed label is attached to these containers in order to impart design properties, product names, and other information. In addition, although what is called a label may be a piece of paper or a film that is printed and affixed to a container with an adhesive, in the present specification, it is a substantially cylindrical shape made of a plastic film or the like. Is attached to the container by shrinking the film by applying heat to the cylinder, and what is attached is called a label.

  For these labels, heat-shrinkable films are mainly used, and polyethylene terephthalate (PET) films, polystyrene films, polyvinyl chloride films, and the like are used as materials.

  In recent years, in order to reduce the burden on the environment, bottle containers such as glass bottles and PET bottles have been recycled, and heat-shrinkable labels attached to them are also subject to recycling. The PET bottle container collected by recycling is crushed and then separated into a PET bottle container and a heat-shrinkable label using the difference in specific gravity. However, since the specific gravity of the heat-shrinkable label using the material described above is close to the specific gravity of the PET bottle container, complete separation is difficult.

  As a method for solving these problems, a heat-shrinkable polyolefin film has recently appeared (see Patent Document 1). Since the specific gravity of this film is light (below 1), there is an advantage that it becomes easy to separate and collect from the PET bottle container in the recycling process, and the amount of use has recently increased rapidly.

  However, this film has solubility in aromatic hydrocarbon solvents such as toluene and xylene, aliphatic hydrocarbon solvents such as n-hexane and n-heptane, and alicyclic hydrocarbon solvents such as cyclohexane and methylcyclohexane. Since it is very high, when printing inks containing them are used, there is a problem that troubles such as label shrinkage and whitening occur.

  Usually, the label surface is printed for the purpose of imparting physical properties such as scratch resistance, antifouling property, and slipperiness, and design properties such as a mat effect. Here, the matte effect means an effect that gives a high-class feeling because the printed surface is matte. As resin binders for printing inks used for these purposes, vinyl chloride / acrylic mixed resin systems have been mainly used in the case of PET and polyvinyl chloride film labels. However, when these resin binders are used, it is necessary to use toluene as a solvent in order to obtain good printability, and as described above, there is a problem of shrinkage or whitening, so it is applicable to heat-shrinkable polyolefin films. Have difficulty.

Polystyrene film is also dissolved in organic solvents such as aromatic hydrocarbons, aliphatic hydrocarbons, and alicyclic hydrocarbons, as with heat-shrinkable polyolefin films. Printing ink cannot be used. As a resin binder used for printing ink for polystyrene film, a cellulose / acrylic mixed resin system has been mainly used from the viewpoint of adhesion to the film and the like. However, when this printing ink is printed on a heat-shrinkable polyolefin film, the adhesion to the film is weak, and furthermore, since the ink film is harder than the film, the sagability when the printed film is rubbed by hand The phenomenon that the printing ink film falls off occurs. For this reason, application to a heat-shrinkable polyolefin film is difficult even for printing inks for polystyrene films.

  Patent Document 2 describes an olefinic heat-shrink label having excellent scratch resistance and antifouling properties. Paragraph 30 of this document describes that a product obtained by subtracting the pigment from the conventional gravure ink can be used as a transparent coating agent for imparting scratch resistance and antifouling properties. Due to problems, it is actually difficult to use.

  Patent Document 3 describes a heat-shrinkable label film and a PET bottle equipped with a label made of the film. As the label film, a film in which a polyolefin resin layer is used as a core and a non-polyolefin resin layer is laminated on both sides of the film via an adhesive resin layer is used. However, there is no suggestion or description regarding the design of a printing ink composition for the purpose of scratch resistance and antifouling properties printed thereon.

JP 2000-246797 A JP 2002-132159 A JP 11-262981 A

  An object of the present invention is to provide a printing ink composition that imparts scratch resistance and antifouling properties to a film without causing shrinkage or whitening of the film when printed on a heat-shrinkable polyolefin film. It is another object of the present invention to provide a laminate in which the printing ink is printed on a film and a bottle container equipped with the laminate.

  As a result of diligent research, the inventors did not contain any of aromatic hydrocarbon solvents, aliphatic hydrocarbon solvents and alicyclic hydrocarbon solvents, and alcohol solvents, ketone solvents and ester solvents. The present invention has been completed by finding that the above-mentioned problems can be solved by printing using a printing ink composition containing at least one selected from the group consisting of solvents. In this ink composition, it is preferable to contain a polyvinyl acetal resin as a resin binder.

  By printing on a heat-shrinkable polyolefin film using the printing ink composition of the present invention, shrinkage and whitening of the film can be prevented, and scratch resistance and antifouling properties can be imparted to the film. Moreover, the bottle container which uses the laminated body which printed the printing ink on the film as a label can maintain the beauty | look when it arranges in a shop front, since the label has scratch resistance and antifouling property.

Embodiments of the printing ink composition according to the present invention will be described below. In the present specification, “part”, “%” and “ratio” are based on mass unless otherwise specified.
The printing ink composition in the present invention comprises a solvent, a resin and an auxiliary agent, and contains a pigment as necessary.

  Examples of (a) aromatic hydrocarbon solvents generally used in conventional printing inks include toluene and xylene. In addition, (b) aliphatic hydrocarbon solvents include n-hexane, n-heptane, n-octane, and (c) alicyclic hydrocarbon solvents include cyclohexane, methylcyclohexane, ethylcyclohexane, cycloheptane, There is cyclooctane. The printing ink of the present invention does not use these solvents (a) to (c) as raw materials, and does not contain them in the ink at all.

  In place of the solvents (a) to (c), alcohol solvents such as methanol, ethanol, isopropyl alcohol, n-propyl alcohol, butyl alcohol, ketones such as acetone and methyl ethyl ketone, ethyl acetate, propyl acetate, etc. However, an alcohol / ester mixed solvent is more preferable for the purpose of reducing the environmental burden of printing work. The alcohol / ester ratio is preferably 90/10 to 30/70.

  As the resin binder in the printing ink, a polyvinyl acetal resin having good adhesion to the heat-shrinkable polyolefin film is used. This polyvinyl acetal resin may be used alone, or may be used by mixing with a resin having compatibility with this resin, for example, a fiber-based resin or a vinyl chloride resin. Further, the content of the polyvinyl acetal resin in the printing ink is approximately 3 to 30%. When the resin concentration is within this range, good fluidity is obtained in the printing ink composition.

  Further, since the polyvinyl acetal resin has good solubility in an alcohol solvent and is tough and has good flexibility, a polyvinyl butyral resin is more preferred, and the butyral group contained in the molecule is 60 mol% to 90 mol. % Is preferred.

  In addition, you may use the well-known adjuvant used for printing ink as needed in the printing ink composition of this invention. For example, a wax, a plasticizer, a leveling agent, a surfactant, an antifoaming agent and the like can be mentioned.

  Moreover, you may use the well-known various inorganic pigment and organic pigment used for printing ink for the purpose of the designability provision etc. in the printing ink of this invention. Examples of these pigments include titanium oxide, bengara, carbon black, calcium carbonate, barium sulfate, copper phthalocyanine pigment, azo lake pigment, soluble azo pigment, insoluble azo pigment, and condensed azo pigment.

  The printing ink composition of the present invention can be obtained by sufficiently mixing and dispersing the above-described solvent, resin, auxiliary agent, pigment, and the like using a stirrer such as a tank mixer and a dispersing machine such as a bead mill and a roll mill.

  The printing ink composition of the present invention thus obtained has good adhesion to the heat-shrinkable olefin film, and further, the printing ink coating film does not slide down even when it is rubbed by hand. Have good coating film properties.

  The laminate of the present invention uses the above printing ink composition. The laminated body in this invention is demonstrated below based on drawing.

  As shown in FIG. 1, the laminate of the present invention is obtained by providing the heat-shrinkable polyolefin film 1 with the printing ink composition 3 described above. The printing form of the printing ink composition 3 is a full surface solid printing excluding a part of the heat-shrinkable polyolefin film or the adhesive surface. As a printing method, printing methods such as offset printing, gravure printing, letterpress printing, and flexographic printing are used. Among them, gravure printing is particularly preferable because of good gradation reproducibility and high quality images.

  Moreover, you may provide the pattern printing layer 2 between the printing ink composition 3 and the heat-shrinkable polyolefin film 1 as needed. In this case, it is preferable that the pattern printing layer 2 is entirely covered with the printing ink composition 3.

  This heat-shrinkable polyolefin film has a specific gravity of 0.99 or less, can be center-sealed with an organic solvent, and is at least amorphous as a film component for the purpose of obtaining a better shrinkage rate and heat shrinkage rate. It is preferable that cyclic polyolefin resin is included.

  The shrinkage ratio in the main shrinkage direction of the film is preferably 25% or less when immersed in hot water at 70 ° C. for 10 seconds, and preferably 40% or more when immersed in hot water at 80 ° C. for 10 seconds. The thickness is 20 to 80 μm, and particularly preferably 30 to 50 μm.

The dry coating amount of the printing ink composition forming the printing ink layer 3 is 0.3 to 2.0 g / m ² , and the thickness is 2 to 20 μm. When the dry coating amount is in the numerical range, sufficient scratch resistance and antifouling properties can be obtained in the printing ink composition, and ink film physical properties such as adhesion and sagability are improved.

Next, the bottle container of the present invention will be described.
Examples of the bottle container include a glass bottle and a plastic bottle represented by polyethylene terephthalate (PET).

  A laminate comprising a heat-shrinkable polyolefin film printed with the printing ink composition of the present invention as a base material is formed into a cylindrical shape so that the main shrinkage direction is the circumferential direction, and used as a label. At that time, the solvent for adhering both ends of the film may be any solvent that dissolves the heat-shrinkable polyolefin film. For example, aromatic hydrocarbon solvents such as toluene and xylene, n-hexane, n-heptane, n-octane aliphatic hydrocarbon solvents, cyclohexane, methylcyclohexane, ethylcyclohexane, cycloheptane, cyclooctane, etc. Examples thereof include hydrocarbon solvents, tetrahydrofuran (THF), 1,3-dioxolane and the like.

  A bottle container is obtained by attaching the above-mentioned label to the bottle container by heat-shrinking. As the heat shrinkage method at this time, hot air, hot water, steam and the like can be mentioned, but steam which does not cause shrinkage unevenness and has the best appearance is more preferable.

  The bottle container obtained in this manner is excellent in scratch resistance and excellent in antifouling properties when lined up in a store.

  Hereinafter, the present invention will be described in more detail by way of examples. However, the present invention is not limited to the following examples. Unless otherwise specified, parts and% are based on mass in this specification.

[Preparation of printing ink]
[Example 1]
After mixing 15 parts of Denkabutyral (registered trademark) # 2000L manufactured by Denki Kagaku Kogyo Co., Ltd., 50 parts of isopropyl alcohol and 30 parts of ethyl acetate with stirring and dissolving, polyethylene wax (Dainippon Ink Chemical Co., Ltd., “ NC-6 Polycon ", particle size 5 μm) was added and mixed with stirring to prepare gravure printing ink.

[Comparative Example 1] (Influence of resin amount)
After 40 parts of Denkabutyral (registered trademark) # 2000L manufactured by Denki Kagaku Kogyo Co., Ltd., 30 parts of isopropyl alcohol and 25 parts of ethyl acetate were mixed and stirred and dissolved, polyethylene wax (Dainippon Ink Chemical Co., Ltd., “ NC-6 Polycon ", particle size 5 μm) was added and mixed with stirring to prepare gravure printing ink.

[Comparative Example 2] (Influence of resin system)
After mixing 15 parts of “Acridic (registered trademark) WCL-476” manufactured by Dainippon Ink & Chemicals, Inc., 50 parts of isopropyl alcohol, and 30 parts of ethyl acetate with stirring and dissolving, polyethylene wax (Dainippon Ink Chemical Co., Ltd.) 5 parts of “NC-6 Polycon”, particle size 5 μm) was added and mixed by stirring to prepare a gravure printing ink.

[Comparative Example 3] (Influence of solvent)
After mixing 15 parts of “Denka Butyral (registered trademark) # 2000L” manufactured by Denki Kagaku Kogyo Co., Ltd., 50 parts of isopropyl alcohol, and 30 parts of toluene with stirring and dissolving, polyethylene wax (manufactured by Dainippon Ink Chemical Co., Ltd., “NC 5 parts of “-6 Polycon”, particle size 5 μm) was added and mixed with stirring to prepare gravure printing ink.

[Production of laminate]
After adjusting the viscosity by diluting the above gravure printing ink with a solvent, heat shrinkable polyolefin film ("FL2" manufactured by Gunze Co., Ltd.) with "DICOM PROFER DP-III" auto proofer manufactured by Dainippon Ink & Chemicals, Inc. The color was spread so that the dry coating amount was 0.5 g / m ² .

[Production of bottle containers]
The laminate was formed into a cylindrical shape so that the main shrinkage direction of the heat-shrinkable polyolefin film was the circumferential direction, and then both ends were bonded with a solvent to obtain a heat-shrink label. Next, a heat-shrink label was attached to a PET bottle (internal volume 500 ml) filled with tea, and heat-shrinked by a steam tunnel (temperature 90 ° C.) to obtain a bottle container attached with the label.

[Evaluation of fluidity of printing ink]
The fluidity of the printing ink was evaluated by measuring the ink viscosity using Zahn Cup # 4 (manufactured by Kogaisha).

[Evaluation of laminate]
The coating film strength of the printing ink layer 2 was evaluated by measuring adhesion and stagnation.
Adhesion: evaluated by the degree of adhesion with a cellophane adhesive tape (width 18 mm).
Itching property: Evaluated by the degree of ink slid off when the laminate was hand-rubbed 20 times.

[Evaluation of bottle containers]
Evaluation with a bottle container was performed by measuring shrinkage whitening, scratch resistance and antifouling properties during heat shrinkage.
Shrinkage whitening: Evaluated by surface gloss value (“micro-TRI-gloss” manufactured by BYK, 60 ° / 60 ° measurement).
Scratch resistance: Gakken-type dyeing fastness tester ("RUBING TESTER" manufactured by DAIEI SEIKI) was evaluated at 1000g load and 1000 reciprocations.
Antifouling property: Evaluated by the degree of contamination when left in the open air for 1 month.

  The above measurement results are shown in Table 1.

  In the fluidity, ◯ indicates that the ink viscosity was 15 to 25 seconds (Zahn cup # 4), and × indicates that the ink viscosity was 50 seconds or more (Zahn cup # 4).

  Regarding the coating strength, in the adhesion evaluation, “◯” was 0 to 5% or less of the peeled area ratio of the ink film by the cellophane adhesive tape (area peeled by the cellophane adhesive tape / cellophane adhesive tape contact area × 100). "X" indicates that it was 70 to 100%.

  In the stagnation evaluation, “◯” indicates that the ink sliding area ratio (the area where the ink slid / the stagnation test area by hand × 100) was 0 to 1% or less, and “Δ” was 1 to 10%. “X” indicates that it was 10 to 100%.

  In shrinking whitening, “◯” indicates that the gloss value was 50 to 70, “Δ” indicates 30 to 50, and “x” indicates 30 or less.

  In the scratch resistance, “◯” indicates 0 to 15% in the damaged area ratio of the ink film surface (area where the ink was damaged / test execution area × 100), and “Δ” indicates 15 to 60%. “X” indicates that it was 60 to 100%.

  In antifouling property, “◯” indicates that the dust adhesion amount was 0.1 g or less, and “Δ” indicates that it was 0.1 g to 0.5 g.

  From the measurement results in Table 1, it can be seen that only the printing ink composition of the present invention (Example 1) has excellent performance in all items.

It is sectional drawing which shows an example of the laminated body (label) which concerns on embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Heat-shrinkable polyolefin film 2 Picture printing layer 3 Printing ink composition of this invention

Claims (7)

  Printing that does not contain aromatic hydrocarbon solvents, aliphatic hydrocarbon solvents, and alicyclic hydrocarbon solvents, but contains one or more selected from the group consisting of alcohol solvents, ketone solvents, and ester solvents Ink composition.   The printing ink composition according to claim 1, comprising a polyvinyl acetal resin as the resin binder for the printing ink.   The printing ink composition according to claim 2, comprising 3 to 30% by mass of the polyvinyl acetal resin.   The laminated body which printed the printing ink composition in any one of Claims 1-3 on the heat-shrinkable polyolefin film.   5. The laminate according to claim 4, wherein the heat-shrinkable polyolefin film has a specific gravity of 0.99 or less and includes at least an amorphous cyclic polyolefin resin as a component of the film. Laminate according to claim 4 or claim 5 dry coating amount of the printing ink is 0.3 to 2.0 g / ^{m 2.} A bottle container in which the laminate according to any one of claims 4 to 6 is attached to a bottle container by heat shrinking.

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