JP6417651B2 - Shrink material for packaging, shrink label for packaging using the same, and shrink label laser printing body for packaging - Google Patents

Description

  The present invention is a packaging which can be printed with a laser for quickly covering or binding a part or all of the mouth, shoulder, body, etc. of the container for the purpose of protecting the container, binding, labeling, etc. The present invention relates to a shrink material for packaging, a shrink label for packaging using the same, and a shrink label laser printing body for packaging having printed images by laser on them.

  Conventionally, container protection, binding, labeling on the surface of containers such as plastic bottles, glass bottles, metal cans, etc. in various shapes such as square, round, gourd etc. for filling and packaging various liquid foods etc. As a packaging material that quickly covers or binds part or all of the mouth, shoulder, and trunk of the container for the purpose of sticking and the like, a packaging shrink material is known. As a packaging method using a shrink material, for example, a method is known in which a tubular or bag-shaped film is primarily packaged with a little margin and then the film is shrunk to the outer peripheral surface of the container by hot air, steam, or the like. Yes.

  In addition to forming characters, symbols, drawings, etc. on the surface of packaging containers and bags, and packaging materials that wrap these packages in advance, for example, date of manufacture, manufacturer, product name, expiration date, etc. It is widely known that the additional information is printed later with ink or the like.

Packaging bodies and packaging materials such as packaging containers and packaging bags are used for various purposes, and depending on the purpose and use situation, etc., selection of materials, laminating configuration or so as to meet a wide variety of demands and demands The structure is changed and used as a package. For this reason, the package has a wide variety of laminated structures depending on the form of the package and the change of the material according to the usage situation.
For such a wide variety of packages, there is a need for a technique that can appropriately and accurately print additional information that needs to be written for each packaging material.

  Packaging bodies such as packaging containers and packaging bags and packaging materials are pre-printed on most of the front and back surfaces, and have less margin than containers such as boxes and cans. It is difficult to secure the display area. On the other hand, when the ink layer is displayed on the outer surface of the packaging bag over the existing printed layer, the appearance of the package is impaired, and the ink layer display There is an inconvenience that makes it difficult to read.

  Packaging shrink material is generally used as a label by heat-sealing with a heat seal part located on one surface of packaging shrink material that does not contain opaque packaging materials such as aluminum foil, paper, etc. Or, the package shrink material is coated on the package as it is. The packaging shrink material has an ink layer for displaying necessary characters, symbols, and the like, and is applied to a packaged body for use. The printing area is more limited than that of a packaging container or packaging bag. In such a packaging shrink label, which has a narrow printing area and is a limited packaging body, the packaging shrink material with the additional information clearly and clearly printed at an arbitrary position and with improved visibility, and It is desired to provide a label using the same and a shrink label printing body for packaging.

  Packaging materials such as packaging containers and packaging bags and packaging materials are printed on the surface of packaging bags or the like by a known printing method, inkjet printer, or laser irradiation as a technique for printing additional information, or a laminated structure of packaging materials. It is already known to print additional information between these layers. When printing a predetermined pattern or fixed information, a printing layer can be formed between the layers by inkjet printing or general-purpose printing methods, but additional information that changes the information may not be set in advance. Appropriately, printing may be blurred due to the dryness of printing, compatibility between the package and ink, contact with the printing surface of the package that moves at high speed, etc. The problem is that it cannot be printed accurately.

  In order to solve the conventional problems, in particular, attention has been paid to printing of additional information by laser irradiation. In laser printing, a laser is directly applied to the surface of a plastic molded product or the like formed on a resin composition in which a color former that develops color by laser light is contained in a resin, or such a resin composition layer is formed on the surface. The printed image is formed, and there is a problem that the printed image is faded or erased by rubbing the surface of the laser printed image.

As a technique for printing with a laser beam, printing on a film by irradiating a YAG laser, a YVO ₄ laser, or the like is known. As a multilayer laminated film for laser printing that can be printed by a laser, a film using a special ink that changes color by laser irradiation as an intermediate layer (coloring layer) is known (Patent Document 1).

  Since such special ink is very expensive, the special ink layer is preliminarily provided only on a portion on the base film where printing is desired. However, even in that case, alignment is difficult and the print position cannot be easily changed. In addition, there is a drawback that the printed line is thin and difficult to read.

General inks also change color slightly when irradiated with YAG or YVO ₄ laser. Therefore, it is also known to use such normal ink as an intermediate layer (coloring layer) (Patent Document 2). However, in this method, a printing portion is formed on the intermediate layer by irradiating with a powerful laser beam. In other words, in order to obtain sufficient visibility, the laser power is output until the intermediate layer of the laser-irradiated part is completely evaporated over the entire thickness in the depth direction (direction from one surface of the film to the other surface). Need to increase.

  Accordingly, there is a problem that a hole is formed in the base film by irradiation with a powerful laser beam. In addition, there is a problem that the printing speed is slow because it is necessary to irradiate a powerful laser beam.

JP 2007-55110 A Japanese Patent Laid-Open No. 2007-217048

  The present invention provides a packaging material having a wide variety of laminated structures, particularly a packaging shrink material which is a packaging material having a narrow print area and is limited, and a packaging shrink label using the packaging material. To solve the conventional problems in printing, it is made of an inexpensive material, easy to manufacture, easy to change the printing position, and low output that does not damage the base film By irradiating the laser, a shrinkable packaging line that has an appropriate thickness and is easy to read can be obtained. It is an object of the present invention to provide a material, a label using the same, and a laser printing body thereof.

  As a result of various studies on the shrink material or the label using the same, the present inventors have solved the conventional problem of printing additional information while packaging. In addition, color inks that use inexpensive laser coloring materials that develop colors using low-power laser light are used, and color inks are used as printing foundation layers for printing layers commonly used in packaging and packaging materials. A substrate that becomes a viewing side by forming a region of only a laser coloring ink underlayer that can be printed with a low-power laser beam on a printed layer and irradiating the region with a low-power laser beam from the viewing side. A colored area is formed by spreading the colored ink component only on the surface of the printed image area between the film layer and the printed layer, and an appropriate and accurate arbitrary position on the colored ink underlayer is formed. Laser-coloring agent found packaging shrink material capable of forming a clear laser printed images having a suitable thick lines in colored ink components.

  The present invention is a packaging shrink material comprising a heat-shrinkable substrate, a printing layer comprising a pattern printing layer and a printing underlayer, and the pattern printing layer and the printing underlayer serving as a laser printing layer overlapped. In the packaging shrink material having the area and only the printing underlayer, the printing underlayer is a coloring ink layer that can be printed by laser light including a coloring material that develops color by irradiation with laser light. A layer comprising an ink composition containing a compound, and further comprising one or more compounds selected from metal oxides or composite oxides, or copper-based compounds or molybdenum-based compounds, A color development area developed by laser light is formed only on the surface of the base layer for color ink printing between the base material on the viewing side and the color ink base layer for color printing that can be printed. This is a packaging shrink material for the laser printing region, and can achieve the above-mentioned purpose.

And this invention enables laser printing by the following points in the shrink material for packaging and the shrink label for packaging.
1. A shrinkable packaging material comprising a heat-shrinkable substrate, a printing layer comprising a pattern printing layer and a printing underlayer, and the area where the pattern printing layer and the printing underlayer serving as a laser printing layer overlap with each other for printing In the packaging shrink material having the area of only the foundation layer, the printing foundation layer is a coloring shrinkable ink layer that can be printed with a laser beam containing a coloring material that develops a color when irradiated with laser light. is there.
2. It is preferable to use a bismuth-based compound as the coloring material to form a packaging shrink material because it can be colored and printed by a low-power laser beam.
3. One or more bismuth-based compounds selected from bismuth hydroxide, bismuth oxide, bismuth carbonate and bismuth nitrate are used as packaging shrink materials, which are colored by low-power laser light and printed. Possible and preferred.
4). Coloring inks that contain one or more compounds selected from metal oxides or composite oxides or their groups, and that are made into packaging shrink materials, are colored by low-power laser light and printed. Is possible and preferred.
5. Coloring inks that contain one or more compounds selected from copper-based compounds, molybdenum-based compounds, or groups thereof, and made into shrink materials for packaging, are colored by low-power laser light and are clear Printing is possible and preferable.
6). What formed the packaging shrink label using the said packaging shrink material is colored and can be printed by a low output laser beam, and is preferable.
7). By irradiating the packaging shrink material or packaging shrink label with YAG or YVO ₄ laser light from the substrate side, the color development region of the colored ink composition spreads to the boundary between the substrate and the printing underlayer. A laser-printed image formed by a low-power laser beam and laser-printed with additional information is preferable as a packaging shrink label printing body.

  The packaging shrink material of the present invention is formed in the entire region of the packaging shrink material as a printing base layer using a laser-printable coloring ink containing a coloring material of a bismuth compound that develops color with a low-power laser beam, In addition, it is a packaging shrink material in which a laser printing layer is formed by laminating a required pattern printing layer on the heat-shrinkable substrate side of the printing base layer. In addition, the laser printing area can be formed by irradiating the area with laser.

  The present invention uses a coloring material, in particular a coloring ink layer containing a bismuth compound, as a white pigment used in a commonly used white ink as a base for printing a packaging shrink material, or further a metal oxide, By containing a complex oxide, a copper-based compound, and a molybdenum-based compound, it is possible to develop color with a low-power laser, and as a base layer that can be used as a printing layer for laser printing of additional information, It can also function as a base layer of the pattern printing layer, and a packaging shrink label can be efficiently manufactured from an inexpensive material.

By irradiating the shrink material for packaging of the present invention with a YAG or YVO ₄ laser from the substrate side, the ink component containing the coloring material forming the printing layer is colored and partially carbonized by low-power laser irradiation. Because the color development area spreads at the boundary between the heat-shrinkable substrate and the printing underlayer, it is not necessary to increase the laser output until the output power is weak, that is, until the printing layer is completely evaporated, and the ink as the underlayer A laser-printed image having excellent visibility from the substrate side can be clearly formed by the contrast between the color of the base and the color of the developed color.

  Furthermore, in the printed body of the present invention, the laser printed image is applied not inside the film surface but inside, that is, between the heat-shrinkable substrate and the printing layer. Therefore, since this image has excellent wear resistance, it is possible to effectively prevent disappearance due to rubbing or the like, and to prevent change of the additional information.

  From these advantages, according to the packaging shrink material of the present invention and the packaging shrink label using the same, it is possible to set a region where additional information can be formed in a region other than the heat-sealed portion of the label, For example, variable information such as the date of manufacture, manufacturer, product name, expiration date, production location, etc. can be read more easily than a conventional inkjet printer, and a large amount of information can be printed as a laser print image.

The laser coloring ink layer containing the coloring material of at least the inner layer, such as the layer in contact with the package of the packaging shrink label, becomes a printing layer that can be printed by irradiation with laser light, so that the ink contacts the surface of the packaging shrink material. You can print without letting.
Moreover, in the manufacturing process of the shrink material for packaging, it is only the same printing process as a normal printing process, it is not necessary to provide an additional layer for laser printing, and a manufacturing process can be simplified.

It is a schematic sectional drawing which shows the example about the layer structure of the shrink material for packaging of this invention. It is a schematic sectional drawing which shows the example about the layer structure of the printing body which used the shrink material for packaging which concerns on this invention shown in FIG. 1 of this invention, and irradiated this with the laser beam and formed the laser print image. FIG. 3 is a schematic cross-sectional view showing an example in which the color ink layer is further lined with a printing underlayer or an OP varnish layer in the layer structure of the packaging shrink material of the present invention.

The packaging shrink material according to the present invention, the packaging shrink label using the same, and the layer structure of the printed body will be exemplified and described in detail below with reference to the drawings.
FIG. 1 is a schematic sectional view showing an example of the layer structure of the packaging shrink material of the present invention.
As shown in FIG. 1, the packaging shrink material of the present invention basically has a configuration including a heat-shrinkable base material 1, a pattern printing layer, and a printing layer 2 composed of a laser color ink base layer.

  In another aspect, as shown in FIG. 2, the general-purpose white ink underlayer or overprint varnish layer may be laminated on the side opposite to the base film of the laser color ink underlayer. The packaging shrink material of the present invention may have a structure in which a sealant layer is further laminated on the laser color ink base layer as necessary.

As shown in FIG. 2, the printed material of the present invention is produced by irradiating the shrink material for packaging of the present invention with a YAG or YVO ₄ laser from the substrate side. On the surface of the base layer, it has a printed part in which a colored ink component spreads.

(Heat-shrinkable substrate)
In the present invention, the heat-shrinkable substrate is a resin film according to its intended purpose, application, etc., and when the printing layer is laminated, the laminating strength between the laser ink layer and the pattern printing layer is high. Any resin film obtained sufficiently can be used.

  Specifically, it becomes a basic material, and further, after printing, it constitutes a surface protective layer and can be seen through a laser-printed image, etc., so it is excellent in mechanical, physical, chemical, etc. A resin film having strength, excellent puncture resistance, and the like, and excellent heat resistance, moisture resistance, transparency, and the like can be used.

  When used as a shrink film as in the present invention, as a film constituting such a base film layer, a film that can be shrunk by heat treatment can be widely used, for example, a stretched polyester system such as a stretched polyethylene terephthalate film. Film, stretched polystyrene film, low density polyethylene film, medium density polyethylene film, high density polyethylene film, low density linear polyethylene film, stretched polyolefin film such as polypropylene film, polylactic acid film, foamed polyolefin film, foamed polystyrene It is preferably one or more kinds of films selected from the group consisting of a base film, a laminate film of a nonwoven fabric and a shrink film, and a stretched polyester-polystyrene coextruded film.

  In addition, at the time of film formation using one or more of the above-mentioned various resins, for example, film processability, heat resistance, weather resistance, mechanical properties, dimensional stability, antioxidant properties, slipperiness, release properties, etc. Various plastic compounding agents and additives can be added for the purpose of improving and modifying moldability, flame retardancy, antibacterial properties, electrical properties, strength, laminate strength, etc. Can be arbitrarily added from a very small amount to several tens of percent depending on the purpose.

  In the above, as a general additive, for example, a lubricant, a crosslinking agent, an antioxidant, an ultraviolet absorber, a light stabilizer, a filler, a reinforcing agent, an antistatic agent, a pigment, and the like can be used. Furthermore, a modifying resin or the like can also be used.

In order to adjust the adhesion and adhesion between the laser-colored ink layer and the heat-shrinkable substrate, a desired surface treatment can be applied to any surface before forming the layer, if necessary. As the surface treatment, for example, pretreatment such as corona discharge treatment, ozone treatment, low temperature plasma treatment using oxygen gas or nitrogen gas, glow discharge treatment, oxidation treatment using chemicals or the like can be performed. .
Moreover, you may provide a primer coating agent layer, an undercoat agent layer, an anchor coating agent layer etc. between the white ink layer for lasers and a heat-shrinkable base material, for example.

  Any resin film such as an unstretched film or a stretched film can be used as the resin film. The stretched film may be uniaxially stretched or biaxially stretched, and in the case of a uniaxially stretched film, it may be longitudinally uniaxially stretched or laterally uniaxially stretched. However, in the case of a shrink label in which a shrink label is previously attached to a container and then subjected to heat shrink treatment, a laterally uniaxially stretched film is suitable, whereas the wound label of the present invention is used as a shrink label. However, it is not limited to a laterally uniaxially stretched film, and any of laterally uniaxially stretched, longitudinally uniaxially stretched, and biaxially stretched films can be suitably used.

  On the other hand, in order for the label of the present invention to exhibit the effect as a shrink label, it is preferable that the heat shrinkage rate in the stretching direction is 5 to 85%. In addition, the heat shrinkage rate in this invention is a heat shrinkage rate by 100 degreeC hot water, Comprising: The heat shrinkage rate of an extending | stretching direction shall follow a following formula. Therefore, in the case of a longitudinally uniaxially stretched film, since the shrinking direction is the film flow direction, the thermal shrinkage rate in the flow direction is 5 to 85%, and in the case of a laterally uniaxially stretched film, the film shrinks in the film width direction. The heat shrinkage ratio in the film width direction is 5 to 85%. In the case of a biaxially stretched film, the thermal shrinkage rate is preferably within the above range with respect to any stretching method.

  In the present invention, as the resin film, for example, one or more of the above-described various resins are used, and film forming methods such as an extrusion method, a cast molding method, a T-die method, a cutting method, and an inflation method are used. , A method of forming a film of the above resin alone, or forming a multilayer film by coextrusion using two or more kinds of resins, and further using two or more kinds of resins and mixing them before forming a film. A resin film is manufactured by the method of forming a film, and further, for example, any of a stretched film or the like stretched uniaxially or biaxially using a tenter method or a tubular method is used. be able to.

In the present invention, the thickness of the resin film is not particularly limited, but is appropriately selected within a range not impairing heat resistance, rigidity, mechanical suitability, appearance, etc., and is preferably 10 to 200 μm, more preferably 20 to 70 μm. preferable. For shrink labels, the layer thickness before heat shrinkage is used. If it is too thick, there is a disadvantage that the cost is increased. On the other hand, if it is too thin, strength, rigidity, mechanical suitability and the like are lowered, which is not preferable.
In the present invention, 10 to 200 μm, preferably 20 to 70 μm is most desirable for the reasons described above.

  In the present invention, as the resin film forming the heat-shrinkable substrate, among these, a stretched polyester film, a stretched polystyrene film, a stretched polyolefin film, a polylactic acid film, a foamed polyolefin film, a foamed polystyrene film One or more films selected from the group consisting of a laminate film of a nonwoven fabric and a shrink film and a stretched polyester-polystyrene coextruded film are preferred. The stretched polystyrene film is excellent in terms of stability, processability, cost, heat resistance, chemical resistance, and the like, particularly in applications as packaging materials, and is preferably used as a printing layer described below. When laminating the ink, a preferable laminate strength with the printing layer can be obtained.

(Print layer)
In the present invention, the printing layer includes at least a printing foundation layer composed of a pattern printing layer and a laser-colored white ink layer, and the widely used color ink and laser-colored ink are printed on a heat-shrinkable substrate. It is a layer provided by being laminated by coating or the like.
In the present invention, the picture print layer is formed by printing a desired print picture such as a character, a figure, a symbol, a pattern, and a pattern on a heat-shrinkable substrate using a general printing method.

  On the other hand, the laser coloring ink layer, which is the printing underlayer of the present invention, functions as a laser printing portion that can be colored and printed by laser light, and the laser coloring ink layer is colored by low-power laser light. A coloring ink containing a pigment component containing at least a coloring material is preferably used, and an inorganic compound is used for the pigment component. Preferably, the constituent pigment component includes an inorganic compound such as a white pigment. The printing underlayer can also obtain a clear printed image by further providing a printing underlayer on the laser coloring ink layer and multilayering the printing underlayer.

  As the coloring material that develops color by laser light used in the present invention, a conventionally known coloring material can be used as the coloring material. Specifically, colorants such as dyes and pigments, clays, and the like can be used. Specifically, yellow iron oxide, inorganic lead compounds, manganese violet, cobalt violet, mercury, cobalt, copper, nickel, etc. Metallic compounds, nacreous pigments, silicon compounds, mica, kaolins, silica sand, diatomaceous earth, talc, titanium oxide coated mica, tin dioxide coated mica, antimony coated mica, tin + antimony coated mica, tin One type or two or more types such as + antimony + titanium oxide-coated mica can be used.

  In the present invention, at least a bismuth compound is particularly used as a coloring material that develops color with a low-power laser. Specific examples of the bismuth compound include, but are not limited to, bismuth nitrates such as bismuth oxide, bismuth nitrate, and bismuth oxynitrate, bismuth halides such as bismuth chloride, bismuth oxychloride, bismuth sulfate, and bismuth acetate. Bismuth citrate, bismuth hydroxide, bismuth titanate and the like are mentioned. Among them, bismuth nitrate and bismuth hydroxide are preferable from the viewpoint of easy availability and low cost. As a bismuth-type compound, 1 type, or 2 or more types of compounds can be included. In the present invention, a coloring material containing at least a bismuth compound is used, and other coloring materials than bismuth compounds can be used in combination as long as the coloring material is colored by laser light.

  In the present invention, a coloring material containing at least a bismuth-based compound is used, and a coloring material that develops color with laser light and / or an inorganic compound can be used to increase coloring efficiency. It is possible to use a metal oxide, a composite oxide, a metal salt, or one or more compounds thereof as the inorganic compound, and even if there is an inorganic compound even when irradiated with low-power laser light, Add inorganic compounds to function and / or to increase the whiteness of the white ink containing the coloring material and white pigment by helping the coloring of the coloring material by functioning and increasing the heat generation efficiency of the inorganic compound It is preferable.

  In the present invention, it is possible to use a pigment used in white ink that is generally used as a general-purpose printing foundation layer in printing. Preferably, the metal oxide can contain one or more of titanium oxide, magnesium oxide, zinc oxide, aluminum oxide, silicon oxide, nickel oxide, tin oxide, neodymium oxide, mica, zeolite, kaolinite and the like. .

  In the present invention, not limited to metal oxides, copper compounds, molybdenum compounds, copper / molybdenum composite oxides, copper / tungsten compounds, metal salts, and the like can also be suitably used because they also function as coloring materials. .

  As the copper-based compound, for example, copper, copper oxide, copper halide, formic acid, citric acid, salicylic acid, lauric acid, oxalic acid, maleic acid and other organic acid copper, copper phosphate, hydroxyphosphate copper and the like are suitable. Can be used.

  As the molybdenum-based compound, molybdenum, molybdenum dioxide, molybdenum trioxide, molybdenum chloride, and metal molybdate (metals: K, Zn, Ca, Ni, bismuth, Mg, and the like) can be preferably used.

  As the metal salt, a salt of an acid such as sulfuric acid, nitric acid, oxalic acid, or carbonic acid with a metal such as barium, cobalt, magnesium, nickel, or iron can be used.

  In the present invention, in particular, a laser coloring ink that contains at least a bismuth-based compound as a coloring material and that contains titanium oxide as a white pigment is preferably used.

  The bismuth compound color-developing material that develops color with a low-power laser beam is contained in the range of 0.1 to 95.0% by weight in terms of solid content with respect to the ink composition. In the present invention, the content of the coloring material is preferably 1 to 30% by weight. If it is less than 1% by weight, it is not preferable because the color development, printing is insufficient, and the image becomes unclear, and as the content increases, the color development of the print becomes deeper. The difference in the visibility due to the color is not recognizable, but rather the cost increases, the printing underlayer becomes hard, cracks and strength decreases, and the pigment color of the coloring material itself that develops color when irradiated with laser light is the printing underlayer It is not preferable because of coloring it.

  The content of the inorganic compound including the coloring material that develops color with low-power laser light is 5 to 65% by weight in terms of solid content of the inorganic compound. As the content increases, the color of the print becomes darker, but the content is preferably 5 to 65% by weight. If it is less than 5% by weight, color development, printing is insufficient and unclear, and if it exceeds 65% by weight, it is not preferable because of an increase in inorganic compounds, resulting in increased costs, brittle printing underlayer, and reduced strength. .

  The thickness of the laser coloring ink layer is preferably 0.05 to 20 μm, more preferably about 0.1 to 7 μm. If the thickness of the layer is less than 0.05 μm, color development or printing by a color developing material that develops color by laser beam irradiation may be insufficient or unclear. On the other hand, as the thickness of the layer increases, the color of the print becomes deeper. However, if the thickness of the layer exceeds 20 μm, the coloration and printing by the coloring material that develops color by irradiation with laser light is sufficient. For reasons such as an increase in the cost for using a large amount of toner, a decrease in the strength of the printing base layer, and the pigment color of the coloring material itself that develops color when irradiated with laser light, the laser coloring ink layer is colored. When the amount of the pigment used is the same, the visibility of printing is slightly improved when the additive concentration is high and the layer thickness is thin.

  A printing layer can be formed by diluting the coloring ink of the laser coloring ink layer of the present invention with a conventional solvent, if necessary, and printing or coating on a heat-shrinkable substrate. When there are many metal oxides as a coloring ink component, the film is easily damaged by laser irradiation. Conversely, if the amount of metal oxide is small, the printed image tends to be unclear.

  In the present invention, when a print image is formed on the laser color ink layer, a colored undercoat layer can be further provided on the laser color ink layer for the purpose of improving the visibility of the image. In this case, colors with greatly different contrasts can be arranged, and the back of the image can be shielded, so that the visibility of the printed image is always ensured regardless of the color, transparency, and lighting condition of the package. Can do.

  As the colored under layer, the color and color of the pigment can be arbitrarily selected so that the print can be clearly seen by the color that develops when the laser color ink layer is irradiated with laser light, the color of the color layer itself by laser light, etc. . For example, when the laser coloring ink layer is highly transparent gray and the laser coloring is black, high visibility can be obtained by selecting a white colorant.

  For example, basic lead carbonate, basic lead sulfate, basic lead silicate, zinc white, zinc sulfide, lithopone, antimony trioxide, anatase-type titanium oxide, rutile-type titanium oxide, calcium carbonate, One type or two or more types of white pigments such as zinc oxide and barium sulfate can be used.

  The colored underlayer preferably has a layer thickness of 0.05 to 20 μm, more preferably 0.1 to 5 μm. When the thickness of the layer is less than 0.05 μm, coloring is insufficient and visibility is also insufficient. On the other hand, as the thickness of the layer increases, the color of the print becomes darker and the visibility is improved. In addition, when the content of the coloring component with respect to the entire colored base layer is the same, the concentration of coloring and the visibility of printing are improved by lowering the addition concentration and increasing the thickness of the layer.

  Specific examples of the binder resin constituting the ink include urethane resin, polyester resin, acrylic resin, polyamide resin, vinyl chloride-vinyl acetate copolymer, polyester resin, nitrified cotton, cellulose acetate, cellulose resin, and chlorinated resin. Examples include polypropylene resin, chlorinated polyethylene resin, chlorinated ethylene vinyl acetate resin, and ethylene vinyl acetate resin. These resins are used alone or in combination of two or more.

  In particular, urethane resin, polyamide resin, acrylic resin, nitrified cotton, and vinyl chloride-vinyl acetate copolymer resin are preferably used as the binder resin used as the laser coloring ink layer. In particular, the acrylic resin gives a preferable laminate strength with the heat-shrinkable substrate when laminated on a stretched polyester film, a stretched polystyrene film or the like that is suitably used as the heat-shrinkable substrate. In the color printing using laser light, the color ink components and the metal oxide are appropriately spread between the laser color ink layer and the heat-shrinkable substrate to form a color development area and can be recognized as characters.

In order to adjust the laminate strength of the heat-shrinkable substrate and the printing layer to a desired range, an optional additive may be added to the ink as necessary. Examples of this include addition of a lubricant, an antiblocking agent, a filler, a curing agent, and the like. In addition, various additives such as pigment dispersants, antifoaming agents, leveling agents, waxes, silane coupling agents, preservatives, antioxidants, UV absorbers, rust inhibitors, plasticizers, flame retardants, color developers, etc. It can also be added. These additives are used particularly for the purpose of improving printability, printing effect, and the like, and the type and amount used can be appropriately selected depending on the printing method, printing substrate, and printing conditions.
Further, the laminate strength may be adjusted by subjecting the laminate surface of the heat-shrinkable substrate to a surface treatment such as corona treatment, or by laminating a printing layer on an untreated surface.

In the present invention, in order to obtain a packaging shrink material that is colored by laser light and is clear and free from uneven printing, the amount of ink applied to the laser coloring ink layer is 1.0 to 4.5 g / m after drying. ² and more preferably 2.7 to 3.3 g / m ² . If the printing layer is thicker than this, the film is easily damaged by laser irradiation. Conversely, if it is thinner than this, the printed image tends to be unclear.

  In addition, in order to obtain the laminate strength specified in the present invention between the heat-shrinkable substrate and the printing layer (the pattern printing layer and the laser coloring ink layer), the printing layer and the OP varnish, and other layers such as the printing base layer. Although the pattern printing layer or the laser coloring ink layer can be formed in multiple layers, the strength specified by the one-layer printing layer can be obtained more reliably.

  In addition to printing by a known method such as gravure roll coating, reverse roll coating method, knife coating method, kiss coating method, etc., the method of laminating the printing layer can use methods such as inkjet, immersion, spin coating, In the present invention, a method of laminating by printing is preferable. If a printing machine capable of winding a printed film is used, any of gravure printing, offset printing, letterpress printing, and flexographic printing may be used. In particular, the production process can be simplified by solid printing on the entire surface or a part of the laser coloring ink. It is possible to easily apply a large amount of color ink, and it is possible to print on the entire surface or part of it as a laser color ink, thereby improving the concealment and simplifying the manufacturing process. The gravure printing method is suitable.

In the present invention, in order to obtain a packaging shrink material that is clear by laser light and does not cause printing unevenness, it is suitable that the ink coating amount is 1.0 to 4.5 g / m ² as the coating amount after drying. ing.

(Other layers)
The packaging shrink material of the present invention is printed from a printed pattern with a lot of white parts that are not printed on the substrate film side or the opposite side of the laser coloring ink layer, such as when there is a solid print. OP varnish coating is applied to protect the surface from scratches and dirt and to give strength to the printed matter. OP varnish can be printed in the same way as normal ink. As the OP varnish, an overprint layer can be used in order to provide slippage of the surface opposite to the base material of the label in order to improve slippage when the bottle is mounted. Moreover, in order to make the packaging shrink material into a cylindrical shape, a sealant layer made of a known hot melt adhesive may be partially or entirely laminated as necessary.

(Printing with laser light)
In the present invention, printing is performed using a YAG (yttrium (Y), aluminum (A), garnet (G)) laser beam (wavelength = 1.064 μm) or a YVO ₄ (yttrium vanadate) laser beam (wavelength = 1.64 μm). It is preferable to carry out using. These lasers have the property of transmitting through a transparent body, and by utilizing this property, the generation of smoke and the like during printing can be suppressed, and the color density and the effect on the film can be adjusted. . As a result, it is possible to form a very clear laser-printed image having no holes or the like even when a laser-printed image is formed.

By irradiating these lasers from the heat-shrinkable substrate side of the packaging shrink material, the printed shrink material has a low output and minimizes damage to the film while reducing the color white ink component of the printing layer. Gasification and carbonization are performed to form a gap between the heat-shrinkable substrate and the print layer, and a laser print image can be efficiently formed on the surface of the print layer.
A laser printed image is formed on the surface of the laser-colored ink layer of white ink, whereby an image with excellent visibility from the substrate side is obtained.

In the present invention, the pulse conditions for performing such printing are, for example, an average output of 0.8 to 3 W, more preferably 1.5 to 2.5 W, Q switch, using a YVO ₄ laser machine (Keyence MD-V9600). Pulse conditions having a frequency of 10 to 30 KHz and a scan speed of 300 to 4000 mm / s, more preferably 1000 to 2000 mm / s are used. By performing printing under these conditions, high-speed printing is possible without making holes in the multilayer laminated film for laser printing, and a clear printed image can be obtained.

(Printed body with laser light)
In the printing process on the packaging shrink material or packaging shrink body of the present invention, even if the average output of the laser is set low or the scan speed is set fast, a clear printed image, for example, thick and clear Characters can be printed.

  In the printed body of the present invention, the diameter of the color-developing region formed between the heat-shrinkable substrate and the printed layer by laser spot irradiation is desirably 40 μm to 1 mm, more preferably 400 to 700 μm. The ink component developed in this color development area spreads, and a clear printed image can be obtained by using the white ink of the laser color development ink layer as a background. If the diameter of the coloring area is smaller than this, the printed image is lost or the line width is narrowed, resulting in lack of visibility. Conversely, if it is larger than this, it is not preferable because the image is crushed.

In the present invention, the laser-printed image includes, but is not limited to, letters, numbers, symbols, patterns, and the like.
Moreover, the printing body obtained by printing on the packaging shrink material or packaging shrink label of this invention can be applied suitably as a label printing body of the laminated structure of this invention.

  In the packaging shrink material of the present invention, the printing layer is printed on a region consisting only of white ink that functions as a laser coloring ink layer that is colored by laser light and can be printed. The area where the pattern printing layer provided with the desired color printing layer and the laser coloring ink part, which is not applied, is overlapped with the heat-shrinkable substrate even in an atmosphere under wet heat, has high adhesion, and packaging Combined with the fact that peeling does not occur as a shrink material for printing, it is possible to reliably obtain clear printing in the printing area.

(Packaging label)
A packaging shrink label using the packaging shrink material will be described. Shrink labels for packaging use the above-mentioned shrink material for packaging, and the shrink material is folded in two to form a shrink label that is bonded in a cylindrical shape. Adhesives such as hot melt adhesive on both ends of the shrink label in advance A shrink label for packaging can be manufactured by forming a cylindrical shape by overlapping the shrink label with a hot melt adhesive or other adhesive and heat-sealing the end of the shrink label. .

  In addition, various forms of shrink labels for packaging can be manufactured by heat-sealing with a covering form such as a form covering the entire packaged body. In the above, as a heat sealing method, for example, a known method such as a bar seal, a rotary roll seal, a belt seal, an impulse seal, a high frequency seal, and an ultrasonic seal can be used.

  In the present invention, the packaging label produced as described above is filled and packaged.

EXAMPLES The present invention will be specifically described below with reference to examples, but these do not limit the present invention.
[Example 1]
On one surface of a stretched polyethylene terephthalate film (heat-shrinkable substrate) having a thickness of 50 μm, color ink was applied as a pattern layer to the color ink region by a gravure roll coating method. On top of that, a color ink region is formed by a gravure roll coating method using a laser coloring ink containing 5% by weight of bismuth oxide as a coloring material (in terms of solid content of the ink composition) and containing 15% by weight of titanium dioxide as a white ink pigment. Was applied to the entire surface, and the laser color ink base layer was provided to form a printed layer. Thereby, the shrink material for packaging which has the layer structure of the extending | stretching polyethylene terephthalate film / picture color ink printing layer / coloring ink base layer of this invention was obtained.

[Example 2]
Instead of the stretched polyethylene terephthalate film of the base material used in Example 1, a stretched polystyrene film having a thickness of 50 μm was used, and bismuth oxide was contained as a color forming material (in terms of solid content of the ink composition), and a white ink pigment A printing layer was provided in the same manner as in Example 1 except that an acrylic laser coloring ink containing 18% by weight of titanium dioxide was provided. Thereby, the shrink material for packaging of this invention which has a layer structure of a stretched polystyrene film / picture color ink printing layer / color-forming ink underlayer was obtained.

[Example 3]
In the same manner as in Example 2, a stretched polystyrene film is provided with a printing layer, and further, a white ink (acrylic resin binder) is applied to the entire surface of the printing layer by a gravure roll coating method to provide a general-purpose white ink base layer. A printed layer was obtained. Thereby, the shrink material for packaging of this invention which has a layer structure of a stretched polystyrene film / picture color ink printing layer / color-forming ink underlayer / white ink underlayer was obtained.

[Example 4]
In the same manner as in Example 2, a stretched polystyrene film was provided with a printing layer, and a high-concentration white ink (white ink (OS-MHC) manufactured by Dainichi Seika Kogyo; acrylic resin binder) was applied onto the printing layer. Except for this, a printed layer was provided on the stretched polystyrene film in the same manner as in Example 2. This obtained the shrink material for packaging of this invention which has the layer structure of the stretched polystyrene film of this invention / picture color ink printing layer / coloring ink base layer / white ink base layer.

[Example 5]
In the same way as in Example 2, a stretched polystyrene film was provided with a printing layer, and an overprint varnish (OP varnish) layer (manufactured by Dainichi Seika Kogyo Co., Ltd. (SETNBT varnish)) was formed on the entire surface by gravure roll coating. Coated. Thereby, the shrink material for packaging of the present invention having a layer structure of stretched polystyrene film / pattern color ink printing layer / coloring ink underlayer / OP varnish layer was obtained.

[Examples 6 and 7]
A laser color ink layer was applied by the gravure roll coating method in the same manner as in Example 1 or 2 using a laser color ink in which 3% by weight of copper / molybdenum composite oxide was further added to the laser color ink in Example 1 or 2. A packaging shrink material having a layer structure of stretched polyethylene terephthalate film / picture color ink printing layer / coloring ink underlayer of the present invention, or a stretched polystyrene film, respectively, in the same manner as in Example 1 or 2 except that the printed layer was used. A packaging shrink material of the present invention having a layer structure of: / pattern color ink printing layer / coloring ink underlayer was obtained.

[Comparative Example 1]
In the same manner as in Example 2, instead of using the laser ink in Example 2 for the stretched polystyrene film, white ink of high concrete white ink (OS-M and OS-MHC; acrylic resin binder manufactured by Dainichi Seika Kogyo) is used. In the same manner as in Example 2, a printing base layer was provided to obtain a packaging shrink material.

[Laser printing method]
The packaging shrink materials obtained in Examples 1 to 7 and Comparative Example 1 were irradiated with YVO ₄ laser light from the substrate side under the following conditions to form a laser print image to obtain a printed body.
Laser irradiation conditions For each of the examples and comparative examples, a YVO ₄ laser machine (MD-V9600 manufactured by Keyence Corporation) was used. In Examples 1 and 2, the average output was 2.4 W, the Q switch frequency was 10 KHz, and the scan speed was 1500 mm. In Examples 3 to 5, the average output is 1.5 W, the Q switch frequency is 10 KHz, the scan speed is 1500 mm / s, and the comparative example is an average output of 3.5 W, the Q switch frequency is 10 KHz, and the scan speed is 500 mm / s. Printing was performed under laser irradiation conditions.

(Evaluation method)
For each packaging shrink material shown in the Examples and Comparative Examples, the expiration date is printed on the laser coloring ink underlayer by actually irradiating the laser beam, and the clarity and retention of the characters printed there are maintained. Printed characters such as thickness and color density were judged comprehensively, the printed state was evaluated by visibility, and the appearance after laser irradiation was confirmed.

[Evaluation]
In the packaging shrink materials of Examples 1 to 7, the color former develops color even with laser irradiation with a low output of 2.4 W or 1.5 W, and a thick and clear printed image is formed with a thick line width. A good color laser printing was obtained.

  In addition, by adding a white ink underlayer or OP varnish layer to the laser irradiation side on the laser coloring ink layer, the movement of the laser coloring ink layer even at a lower output than when only the coloring ink layer is used. Is restricted, the background of the color development area is firmly fixed, the occurrence of bleeding is suppressed, and the color development ink layer is not blown off by the laser, and the visibility is improved.

  Furthermore, in particular, the system in which the copper / molybdenum composite oxides of Examples 6 and 7 were added exhibited a color development superior to that of the color material-only system, and the copper / molybdenum composite oxide functions as a color development material and further as a color development aid. Laser printing with good discrimination and good visibility was obtained.

  On the other hand, the packaging shrink material of Comparative Example 1 uses the same laser ink under the same low-power laser irradiation, but does not develop color, blurs characters, does not have clear outlines, is inferior in sharpness, and has a thick character. In addition, it was too thin to print with good visibility and discrimination.

  In order to obtain the same level of visibility as in the examples, the laser irradiation conditions were set to high energy irradiation, and before the visibility printing was obtained, a hole was opened in the heat shrinkable substrate of the shrink material for packaging by laser irradiation, Or shrinkage | contraction produced partially, the external appearance deteriorated as a packaging label, and it was a thing which cannot be used. In addition, bleeding occurred because the ink of the white ink layer for laser was scattered. In the comparative example, the appropriate printing range was narrow.

1. 1. heat-shrinkable substrate Print layer 2a. Picture printing layer 2b. 2. Laser color ink base layer White underlayer or OP varnish layer Print section

Claims (6)

A shrinkable packaging material comprising a heat-shrinkable substrate, a printing layer having a pattern printing layer and a printing underlayer, and the region where the pattern printing layer and the printing underlayer serving as a laser printing layer overlap with each other for printing In the shrink material for packaging which has the area only of the foundation layer,
The packaging underlayer is a shrinkable coloring material for packaging, which is a colored ink underlayer that can be colored and printed by a laser beam containing a bismuth compound and a white pigment .   The shrink material for packaging according to claim 1, wherein the bismuth compound is one or more compounds selected from bismuth hydroxide, bismuth oxide, bismuth carbonate and bismuth nitrate.   The shrink material for packaging according to claim 1 or 2, wherein the color ink contains one or more compounds selected from a metal oxide or a composite oxide or a group thereof.   The packaging shrink material according to any one of claims 1 to 3, wherein the color ink contains one or more compounds selected from a copper compound, a molybdenum compound, or a group thereof.   The packaging shrink label using the packaging shrink material as described in any one of Claims 1-4.   By irradiating the shrink material for packaging according to any one of claims 1 to 4 or the label according to claim 5 with YAG or YVO4 laser light from the substrate side, the color development region of the color ink composition is changed to the substrate and A shrink-link laser printing body for packaging which spreads on the boundary of the printing base layer and has a laser print image.

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