JP5529368B2 - Shading ink - Google Patents

Description

  The present invention relates to a packaging material and an ink that can impart light-shielding properties to a packaging container using the packaging material and has little odor when printed. More specifically, by printing on a packaging material having a laminated structure using paper as a main material, quality deterioration due to light of the contents in the packaging container using the packaging material is suppressed, and the contents are given a strange odor. It relates to an ink that has nothing.

  In recent years, beverages such as milk and juice have been evaluated for cost advantage and convenience, and a packaging container (hereinafter also referred to as “paper pack container”) having a structure in which a paperboard is mainly laminated with a polyolefin resin is mainly used. Many are used. Since these paper pack containers have a structure in which they are laminated with paper and a polyolefin resin layer or the like, a considerable amount of light is transmitted. Therefore, the contents such as milk and juice packed in these paper pack containers are affected by light during the distribution process and display in the store, and change in taste, aroma, and the like.

  In order to cope with the change in the contents due to the transmitted light, that is, the quality deterioration, the conventional paper pack container has dealt with using a light-shielding aluminum foil attached to the inside of the container. Although this container and package fulfills a sufficient function with respect to light shielding properties, it not only increases the cost, but also has a difficulty in recycling.

  Therefore, Patent Document 1 is provided with a light-shielding printing layer in which an ink containing carbon black is applied between the base material and the innermost layer of the packaging material, and a colored printing layer positioned inside the light-shielding printing layer. A packaging material for a paper pack is disclosed.

  Patent Document 2 is a packaging material that does not include an aluminum foil, and is provided with a design printing layer, a white printing layer, a light-shielding colored printing layer outside the paper layer of the base material, and a thermoplastic resin disposed on the innermost layer. A packaging material is disclosed.

JP 7-52328 A JP 2002-255158 A

  A material coated with ink containing carbon black for light shielding is excellent in light shielding properties, but has poor design properties, and it must be said that it is difficult to adopt as a container for stimulating consumers' willingness to purchase. Therefore, as in Patent Document 1, design printing is further performed on the black printing layer. However, the black printing as a base has a great influence on the design printing, resulting in a deterioration in the quality of the design printing.

  In Patent Document 2, in order to reduce the influence of the black ink on the design print layer, a white print layer is provided and a design print layer is provided thereon. However, the number of processes increases and the cost increases.

  Further, there are problems of odor due to the solvent used in the ink, carbon black and the like, and further, these odors are transferred to the contents.

  Furthermore, when printing the light-shielding ink on the outermost layer, the light-shielding performance decreases when the print is peeled off, so the ink must have adhesion and friction resistance that can withstand rubbing during transportation. Is done.

  By the way, so-called silver ink is known in which finely divided aluminum is dispersed in a hydrocarbon solvent having a high boiling point such as mineral spirits to form a paste, and the so-called silver ink is dispersed in medium. It is used for printed matter with design. This type of silver ink can be expected to give a certain degree of light-shielding properties to the printed matter, but the printed matter has low adhesion and friction resistance and also has a problem of odor due to hydrocarbon solvents.

  Therefore, the present invention does not adversely affect the design of the packaging container and the cleanliness of appearance, can easily impart light shielding properties to the paper container, and has less odor. It is an object of the present invention to provide a paper pack ink that does not change odor and has excellent adhesion and friction resistance, and a paper pack container using the paper pack ink.

  As a result of examining a method for imparting light-shielding properties to a packaging container without sacrificing design properties, the present inventors have selected the specific aluminum paste and further devised other additives to solve the above problem. As a result, the present invention has been completed.

In order to solve the above problems, the invention according to claim 1 is one kind selected from ethyl acetate and n-propyl acetate which are low boiling ester solvents and ethanol and isopropyl alcohol which are low boiling alcohol solvents. Alternatively, it is a light-shielding ink characterized by containing non-leafing type aluminum paste, polyethylene wax and colloidal silica dispersed in two or more kinds.

The invention according to claim 2 is the light-shielding ink according to claim 1, wherein the light-shielding ink does not contain carbon black .

The invention according to claim 3 is the light-shielding ink according to claim 1, wherein the aluminum fine particles in the aluminum paste have an average particle diameter of 5 to 15 μm.
The invention according to claim 4 is the light-shielding ink according to any one of claims 1 to 3, wherein the content of the aluminum fine particles is 10 to 20% by weight .

The invention according to claim 5 is a laminated packaging material provided with a synthetic resin layer on the inner surface and outer surface of a paperboard substrate. Ethyl acetate and n-propyl acetate which are low boiling ester solvents and ethanol which is a low boiling alcohol solvent. And a light-shielding printing layer using a light-shielding ink containing non-leafing type aluminum paste, polyethylene wax and silica dispersed in one or two or more selected from isopropyl alcohol It is a light-shielding laminated packaging material .
The invention according to claim 6 is the light-shielding laminated packaging material according to claim 5, wherein the light-shielding ink does not contain carbon black.
The invention according to claim 7 is the light-shielding laminated packaging material according to claim 5 or 6, wherein the aluminum fine particles in the aluminum paste have an average particle diameter of 5 to 15 µm.

The invention according to claim 8 is the light-shielding laminated packaging material according to any one of claims 5 to 7 , wherein the content of the aluminum fine particles is 10 to 20% by weight .

The invention which concerns on Claim 9 is a packaging container produced from the light-shielding laminated packaging material in any one of Claims 5-8 .

  According to the present invention, the ink of the present invention provides excellent light-shielding properties by a very simple means of printing on a packaging material and a packaging container using the packaging material, particularly a paper pack container, and suppresses deterioration of the contents due to light. In addition, it does not give off a strange odor to the contents and has a higher light shielding property than ordinary inks. In addition, the printed layer of the ink of the present invention is excellent in adhesion and friction resistance and resists rubbing during transportation, etc., so that the light shielding property is maintained.

  In addition, since it is possible to form a silvery light-shielding printing layer with high brightness without using black ink using carbon black, etc., even if design printing is performed on this, the base color does not affect the design printing. The design printing of a free color becomes possible by normal printing.

  Furthermore, since the light-shielding laminated packaging material of the present invention and the packaging container produced therefrom do not use aluminum foil or the like, there is no influence on the metal detector.

  Hereinafter, the best mode for carrying out the present invention will be described in detail. Note that this embodiment is merely an embodiment for carrying out the present invention, and the present invention is not limited by this embodiment, and various modified embodiments can be made without departing from the gist of the present invention. Is possible.

  Ordinary silver ink is obtained by dispersing an aluminum paste in medium so that aluminum fine particles having an average particle diameter of 5 to 20 μm are 5 to 20% by weight with respect to the ink weight. The aluminum paste is a paste in which aluminum fine particles are dispersed in mineral spirits having a high boiling point. The light-shielding ink of the present invention is based on the silver ink as described below. Improvements were made to improve light-shielding properties, brightness, adhesion, and friction resistance.

  The aluminum paste used in the light-shielding ink of the present invention is obtained by dispersing non-leafing type aluminum fine particles in a low-boiling ester solvent and / or a low-boiling alcohol solvent. The mixing ratio of the aluminum fine particles and the solvent in the aluminum paste is about 6/4 to 7/3 by weight.

  The aluminum paste is generally dispersed in mineral spirits, but in the present invention, the mineral spirit is substituted with a low-boiling ester solvent and / or a low-boiling alcohol solvent. As a result, the odor due to mineral spirit, which is a high-boiling solvent, is reduced, and when the printed material is produced, the odor is hardly felt and the contents are not given a strange odor.

  The low-boiling ester solvent is preferably a lower alkyl ester such as ethyl acetate or n-propyl acetate, and the low-boiling alcohol solvent is preferably a lower alcohol such as ethanol or isopropyl alcohol.

  The aluminum fine particles used for the aluminum paste are preferably non-leafing type. Leafing type aluminum paste has poor friction resistance and ink film adhesion because aluminum fine particles float on the surface. On the other hand, since the non-leafing type has the property of being randomly dispersed in the ink film, the resin used for the ink material easily enters between the flaky aluminum fine particles. As a result, the adhesion of the ink film is improved and the friction resistance is improved without peeling off.

  The average particle size of the aluminum fine particles is preferably 5 to 15 μm. If the average particle size of the aluminum fine particles is smaller than 5 μm, the brightness is greatly reduced and the design is not satisfactory, and the adhesion of the ink film is reduced, and the aluminum particles are easily peeled off. On the other hand, if it exceeds 15 μm, sedimentation in the ink tends to occur, and when printing is performed, there are many omissions and the concealing property is lowered, so that the light shielding property is lowered. In addition, the average particle diameter here is a measured value by a laser method (manufactured by MICROTRAC 9320-X100 Honeywell).

  The addition amount of the aluminum fine particles is 10 to 20% by weight with respect to the ink of the present invention. If the addition amount of the aluminum fine particles is less than 10% by weight, the brightness is lowered and the printed matter lacks design properties, and the light shielding property of the printed matter becomes insufficient. On the other hand, if it exceeds 20% by weight, plate clogging, two-to-stain and the like are likely to occur, and the adhesiveness is also deteriorated.

  The polyethylene wax used for the light-shielding ink of the present invention is 0.5 to 2.0% by weight based on the ink. When the added amount of the polyethylene wax is less than 0.5% by weight, the friction resistance is insufficient and the ink is easily taken. On the other hand, if it exceeds 2.0% by weight, it is not preferable because it is excessively added and not only printability is lowered but also slippery and gloss is lowered.

In the light-shielding ink of the present invention, in order to further improve the friction resistance, silica having a particle diameter of 5 to 100 nm is added. As the silica, colloidal in which silica fine particles are uniformly dispersed in a solvent. Silica is preferably used, and the dispersion solvent is preferably a low-boiling ester solvent and / or a low-boiling alcohol solvent similarly to the dispersion solvent of the aluminum paste.
The amount of colloidal silica added is preferably 1 to 10% by weight based on the ink. If the addition amount is less than 1% by weight, the effect of improving the friction resistance is insufficient. If the addition amount exceeds 10% by weight, not only an excessive amount is practically used, but also the cost increases, which is not preferable. The particle diameter of silica is a value measured by the BET method.

  The light-shielding ink of the present invention is solid-printed on a portion of the laminated packaging material provided with a synthetic resin layer on the inner surface and outer surface of the paperboard substrate that requires light-shielding properties (light-shielding printing layer), and a design printing layer thereon And assemble it into a paper pack container.

  As for the thickness of the light-shielding printing layer by the light-shielding ink of this invention, 1-20 micrometers is preferable. If it is less than 1 μm, the light-shielding property is insufficient, and if it exceeds 20 μm, not only is it practically excessive, but also the cost is increased. As a printing method, a gravure printing method, an offset printing method, a flexographic printing method, or the like can be adopted, but a gravure printing method is preferable.

  Hereinafter, specific examples will be described.

<Examples 1-4>
The ingredients of Table 1 were mixed and dispersed to produce a light-shielding ink. The aluminum paste used is a non-leafing type, and is an isopropyl alcohol dispersion having an average particle size of 9 μm and a content of 70% by weight. The colloidal silica used in Example 4 is an isopropyl alcohol dispersion having a particle size of 40 to 50 nm and a content of 30% by weight as shown in the note of Table 1.

<Comparative Examples 1-7>
Inks were prepared by mixing and dispersing the ingredients of the formulation shown in Table 2. The aluminum paste used in Comparative Examples 1 to 3 is the same as that used in Examples, but Comparative Examples 4 and 5 are non-leafing type (average particle size 9 μm, content 70% by weight, mineral spirits). Comparative Example 6 is a leafing type (average particle size 6 μm, content 67 wt%, mineral spirit dispersion), and Comparative Example 7 is a non-leafing type (average particle size 21 μm, content 71 wt%). Mineral spirit dispersion).

<Preparation of solid printing packaging material>
Roll paper manufactured by Enso Co., Ltd. as a base paper (width 587 mm × length 4000 mm × thickness 0.43 mm, outer surface thermoplastic resin layer having a thickness of 0.017 mm on the upper surface, and inner surface thermoplastic resin layer having a thickness of 0.027 mm on the lower surface The inks produced in Examples 1 to 4 and Comparative Examples 1 to 7 were subjected to gravure printing with a solid thickness of 10 μm. In addition, the packaging material which printed Examples 1-4 was made into samples 1-4, respectively, and Comparative Examples 1-7 were made into samples 5-11, respectively.
In addition, Sample 12 (red printing), Sample 13 (blue printing), Sample 14 (yellow printing), Sample 15 (black printing) using the LRC-NT ink series manufactured by Tokyo Ink Co., Ltd. Printing) and Sample 16 (plain base paper not printed) were prepared.

<Light transmittance>
About the sample 1 and the samples 12-16, the transmittance | permeability in 230 nm-830 nm was measured using the Ubest series V-560iRM / DS spectrophotometer by JASCO Corporation, and the result is shown in FIGS. Indicated.

<Abrasion resistance and water resistance>
Using the Gakken type fastness tester (AB-301, manufactured by Tester Sangyo Co., Ltd.), the test piece of <Preparation of solid printing packaging material> was subjected to 50 reciprocating frictions with a load of 500 g according to JIS-P8136. A test was conducted. As a result, the dirt state of the friction paper was compared with the gray scale for pollution, and the five grades were evaluated with 5 being no dirt, and the results are shown in Table 3. In the water friction resistance test, a cotton cloth soaked with water was used.

<Adhesion>
When the cellophane adhesive tape (CT405AP-18 manufactured by Nichiban Co., Ltd.) was pressed against the printing surface of the test piece of <Preparation of solid printing packaging material>, the cellophane adhesive tape was peeled off. The case where it was not taken was evaluated as ◯, the case where it was partly taken as Δ, and the case where it was taken as x.

From Table 3, Samples 1 to 4 produced using the inks of Examples 1 to 4 show excellent friction resistance and water friction resistance, respectively, and the adhesion is almost good. On the other hand, it can be seen that Sample 6 that does not use polyethylene wax and Sample 7 that does not use colloidal silica both have reduced friction resistance and water friction resistance.
In addition, when an ink having an aluminum content exceeding 20% is used as in Sample 8, a leafing type aluminum paste is used as in Sample 10, or an aluminum paste having a large particle diameter as in Sample 11 is used. In addition to the friction resistance and water friction resistance, it can be seen that the adhesion is reduced.

<Sensory test>
Using the packaging material produced in <Preparation of solid printing packaging material>, a 1-liter paper pack container was assembled, and this was filled with non-component milk and sealed. This sealed paper container containing milk was stored in a shop window refrigerator for one week, and three panelists evaluated changes in taste and smell. The average values are shown in Table 4. The temperature inside the refrigerator during storage was 4 to 8 ° C., and the fluorescent lamps in the store and the show window were continuously lit.
3: Little change in taste and smell.
2: A slight change in taste and smell is felt.
1: Obvious changes in taste and odor.

  From Table 4, when using aluminum paste dispersed in isopropyl alcohol, as in Samples 1-3, 6 and 7, all have little or no change in taste and odor, but aluminum dispersed in mineral spirits It can be seen that Samples 8 to 11 using the paste, Sample 13 for blue printing, Sample 14 for yellow printing, and Sample 16 for plain base paper have large changes in taste and odor. Further, as in Sample 5, even when an aluminum paste dispersed in isopropyl alcohol is used, if the aluminum content is less than 10%, the change in taste and odor is large. Further, when comparing the light transmittance of Sample 1 and Samples 13 to 16 with the magnitude of the change in taste and odor, the samples 13 to 16 having a large light transmittance have large changes in taste and odor, but the light transmission is large. There was no change in Sample 1 with a low rate.

<Evaluation test for designability>
The design property of the packaging material produced in <Preparation of solid printing packaging material> was evaluated based on luminance and concealment. For brightness, the case where the shine of the packaging material looks good is evaluated as ○, and the defect is evaluated as X, and the concealment property is the same as when the packaging material is viewed indoors over the light of a fluorescent lamp. Evaluations were made with ○ being transparent, Δ being less, and × being more. The results are shown in Table 5.

<Metal detector test>
As a result of conducting a metal reaction confirmation test using a metal detector installed in a production line for beverages, etc., using the paper pack container assembled in the above <Sensory test>, no metal reaction was shown. As a result, it was confirmed that the packaging container of the present invention does not interfere with the detection of the metal foreign object that should react with the metal detector because the packaging container itself does not react with the metal detector.

It is a figure which shows the light transmittance of the sample 1. It is a figure which shows the light transmittance of the packaging material of the sample 12. FIG. It is a figure which shows the light transmittance of the packaging material of the sample 13. FIG. It is a figure which shows the light transmittance of the packaging material of the sample 14. FIG. It is a figure which shows the light transmittance of the packaging material of the sample 15. FIG. It is a figure which shows the light transmittance of the packaging material of the sample 16. FIG.

Claims (9)

Non-leafing type aluminum paste dispersed in one or more selected from either low-boiling ester solvents ethyl acetate and n-propyl acetate and low-boiling alcohol solvents ethanol and isopropyl alcohol, polyethylene A light-shielding ink comprising a wax and colloidal silica.   The light-shielding ink according to claim 1, wherein the light-shielding ink does not contain carbon black.   The light-shielding ink according to claim 1 or 2, wherein the aluminum fine particles in the aluminum paste have an average particle diameter of 5 to 15 µm.   The light-shielding ink according to any one of claims 1 to 3, wherein the content of the aluminum fine particles is 10 to 20% by weight. In the laminated packaging material provided with a synthetic resin layer on the inner and outer surfaces of the paperboard substrate, it is selected from either low-boiling ester solvent ethyl acetate and n-propyl acetate and low-boiling alcohol solvent ethanol or isopropyl alcohol. A light-shielding laminated packaging material comprising a light-shielding printing layer using a light-shielding ink containing non-leafing type aluminum paste, polyethylene wax and silica dispersed in one or more kinds . The light-shielding laminated packaging material according to claim 5, wherein the light-shielding ink does not contain carbon black . The light-shielding laminated packaging material according to claim 5 or 6, wherein the aluminum fine particles in the aluminum paste have an average particle diameter of 5 to 15 µm . 8. The light-shielding laminated packaging material according to claim 5, wherein the content of the aluminum fine particles is 10 to 20% by weight . The packaging container produced from the light-shielding laminated packaging material in any one of Claims 5-8.