JP2015066721A - Packaging laminate retort material and packaging retort body employing the same as well as packaging retort laser printed body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a packaging laminate retort material, packaging retort body, and packaging retort printed body made therefrom, that can form, by irradiating a low power laser that does not damage the film, a thick and easy to read printed line.SOLUTION: Provided are: a packaging laminate retort material, that can be printed by YAG or YVOlaser, composed of at least a substrate, a picture print layer, a print ground layer and a sealant layer, in which the region of only the print ground layer directly in contact with the substrate is made to be a laser print region and the print ground layer is a layer composed of an ink composition comprising a bismuth-based compound and other inorganic compounds, and is a laser color-development ink ground layer that develops color by laser beam and is capable of printing; a packaging retort body; as well as a packaging laminate retort laser printed body produced by color-developer-printing said retort material or said retort body with laser.

Description

  The present invention relates to a packaging retort material capable of printing fine figures and characters for filling and packaging foods and drinks, pharmaceuticals, quasi-drugs, medical devices and the like with a low-power laser, and a packaging laminate using the same. The present invention relates to a retort body and a retort laser printing body for packaging having a printed image by laser on them.

  Conventionally, in addition to forming patterns such as letters, symbols, and drawings in advance on the surface of packaging containers such as cans, bottles, plastic bottles, packaging bags, and packaging materials for packaging them, for example, manufacturing A method for printing additional information such as date, manufacturer, product name, and expiration date later with ink or the like is widely known.

The packaging containers or packaging materials that make up the package are used in various applications, and depending on the purpose and use situation, etc., the selection of materials, the layered configuration or the structure can be made to meet a wide variety of requirements and demands. Changed and used as a package. For this reason, the package has a variety of laminated structures depending on the form of the package, the change of the material according to the use situation, and the like.
For such a wide variety of packaging materials, there is a need for a technique that can appropriately and accurately print additional information that requires a description for each packaging material.

  On the other hand, as a technique for printing additional information on a packaging container such as a packaging bag or a packaging material, which is a packaging body, a known printing method, an ink jet printer, laser irradiation, or the like, the surface of the packaging bag or packaging It is already known that additional information is printed between layers of a laminated structure of materials. When printing a predetermined pattern or fixed information on a packaging container or packaging material, a printing layer can be formed between layers by inkjet printing or general-purpose printing methods, but additional information that changes the information cannot be set in advance. In some cases, it may be printed on the surface of the package, the printing may dry out, the compatibility between the package and ink, the contact of the printed surface of the package moving at high speed, etc. The problem is that printing cannot be performed appropriately and accurately, such as in the state of.

  In particular, in packaging materials having a wide variety of laminated structures, it has a laminated structure imparted with a barrier property, and can withstand retort sterilization treatment, which means that it is sterilized with heat and heat exceeding 100 ° C. under pressure, Conventional problems in printing additional information while packaging in packaging retort materials and packaging retorts that are intended to be used under harsh conditions that are required to have retort resistance Packaging retort material and packaging retort that can improve the visibility by properly and accurately, freely and clearly printing additional information on the laminated retort material and packaging retort There is a need to provide bodies and their printed bodies.

As a technique for printing with a laser beam, it is conventionally known to print on a film by irradiating a YAG laser or YVO ₄ laser or the like. As a multilayer laminated film for packaging that can be printed with 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).

And since such special ink is very expensive, providing this special ink layer only in the part which wants to print on a base material is performed beforehand. However, even in that case, alignment is difficult and the print position cannot be easily changed. Also, the printed line is thin,
There is a drawback that it is difficult to read.

Ordinary inks also change color slightly upon irradiation with a 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, it is necessary to form a printing portion in the intermediate layer by irradiating with powerful laser light. 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 is a packaging material having a wide variety of laminated structures, in particular, a laminated retort material for packaging and a retort material for packaging, which is a packaging body that provides barrier properties and is limited to a laminated structure having retort resistance. In order to solve the conventional problems in printing additional information during packaging, it is made of inexpensive materials, easy to manufacture, easy to change the printing position, and damages the base film. By irradiating a low-power laser of an unprecedented level, a print line having an appropriate thickness and easy to read can be obtained. Additional information can be printed appropriately and accurately at any position and clearly, improving visibility. Another object is to provide a laminated retort material for packaging, a packaging retort body using the same, and a printed body thereof.

  As a result of various researches, the present inventors added a packaging retort material or a packaging retort body that is a packaging body limited to a laminated structure having barrier properties and having retort resistance. In order to solve the conventional problems in printing information, white ink that is easy to obtain and highly versatile, and color ink that uses inexpensive laser coloring material that colors using low-power laser light are used. In addition, color ink is used as a printing foundation layer for printing layers generally applied to packaging and packaging materials, and only the laser coloring ink foundation layer that can be printed with low-power laser light is formed on the printing layer. Ink that is colored only on the surface of the printed image area between the base film layer and the printed layer on the viewing side by irradiating the area with low-power laser light from the viewing side. A color development area is formed by spreading the part, and a clear laser-printed image with a moderately thick line is formed with an ink component in which a laser color former develops color at an appropriate and accurate position on the color ink base layer. We have found a laminated retort material for packaging.

  The present invention is a laminated retort material for packaging which is laminated in the order of a substrate, a pattern printing layer, a printing underlayer, a polyamide resin, and a sealant layer, and includes a gas barrier layer, the pattern printing layer and the laser printing layer, In a packaging laminated retort material having a printed layer in which only the printing underlayer is overlapped and a printing layer in which only the printing underlayer is formed, the printing underlayer is a coloring material that develops color when irradiated with laser light. One or two or more compounds selected from metal oxides or composite oxides, or copper-based compounds or molybdenum-based compounds, in particular, including a bismuth-based compound that is a color-forming ink layer that can be printed with a laser beam A color development ink between a base material on the viewing side of a laminated retort material for packaging and a base layer for color ink printing capable of coloring and printing. This is a laminated retort material for packaging, which is a laser printing region that forms a color development region colored by laser light only on the surface of the ink-printing undercoat layer, and can achieve the above object.

The present invention makes it possible to perform laser printing from the following points in a laminated retort material for packaging and a laminated retort body for packaging having a specific layer structure to which barrier properties are imparted and having retort resistance.
1. Laminating retort material for packaging, which is laminated in the order of base material, pattern printing layer, printing base layer, polyamide resin, sealant layer, and has a gas barrier layer, under which printing pattern layer and laser printing layer become In a laminated retort material for packaging having a printed layer in which only a base layer for printing is formed and a region where the base layer overlaps, the base layer for printing is formed by laser light containing a coloring material that develops color when irradiated with laser light. It is a colorable ink layer that can be printed, and is a laminated retort material for packaging in which the region of only the printing base layer is the region for laser printing.
2. A laminated retort material for packaging using a bismuth compound as the coloring material is preferable because it can be colored by low-power laser light and can be printed.
3. A laminated retort material for packaging that uses one or more compounds selected from bismuth hydroxide, bismuth oxide, bismuth carbonate, and bismuth nitrate can be colored with low-power laser light and clear. Therefore, it is preferable that laser printing is possible.
4). Colored ink that contains one or more compounds selected from the group consisting of metal oxides, complex oxides, or their groups, and that is used as a packaging retort material for packaging, develops color with low-power laser light. Clear printing is possible and preferable.
5. Colored inks that use one or two or more compounds selected from copper-based compounds, molybdenum-based compounds, or groups thereof, and made into a laminated retort material for packaging, especially with low-power laser light Color development and clear laser printing are possible and preferable.
6). It is preferable that the gas barrier layer is a gas barrier transparent vapor deposition layer, and a laminated retort material for packaging used as a transparent vapor deposition film provided with a gas barrier transparent vapor deposition layer on a substrate is capable of laser printing.
7). The gas barrier layer is an aluminum metal layer, and a laminated retort material for packaging positioned on the opposite side of the substrate of the laser color ink layer, which is the printing underlayer, is preferable because laser printing is possible. .
8). What was made into the packaging retort body using the said lamination | stacking retort material for packaging is possible because laser printing is possible.
9. The above-mentioned laminated retort material for packaging or packaging for retort, and the colored retort of the ink composition that has developed color by irradiating the packaging retort with YAG or YVO ₄ laser light from the substrate side while filling the contents Is spread on the boundary between the base material and the printing underlayer, a laser-printed image is formed, and the additional information is laser-printed so that the retort printed material for packaging is preferable.

  The laminated retort material for packaging of the present invention does not need to use expensive special ink for laser printing, for example, using a white ink that is generally used as a base for printing a packaging film. In addition, by using a color ink containing a coloring material that can be printed and printed with a low-power laser beam as a base layer for printing, it can be used for general purposes as a base when printing printed pattern layers on packaging films. Using a white pigment that has been printed, a colored ink layer that can be colored and printed by laser light is printed on the entire layer of the packaging retort material, and the required pattern printing layer is printed It is a laminated retort material for packaging in which an undercoat layer for printing that can be printed by laser light is formed over the entire area by stacking layers on the substrate side of , A region of only the print base layer can be provided at any position, yet it can be a laser print area is colored by irradiating laser having a low output region.

  The present invention uses a coloring material, particularly 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 package, or further a metal oxide, a composite oxidation As a base layer that can be colored with a low-power laser and can be used as a printing layer for laser printing of additional information. It can function as a base layer of the printing layer, and can efficiently produce a laminated retort material for packaging from an inexpensive material.

By irradiating the laminated retort 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 by the low-power laser irradiation and partially carbonized. However, since the color development area is widened at the boundary between the base material and the printing underlayer, the output is weak, that is, there is no need to increase the laser output until the entire printing layer is evaporated, and the white ink base as the base With this contrast, a laser-printed image having excellent visibility from the substrate side can be clearly formed.

  Further, 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 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 laminated retort material for packaging of the present invention and the packaging retort body using the same, additional information can be formed in a region other than the heat-sealed portion of the retort body. Variable information such as date of manufacture, manufacturer, product name, expiration date, and production location is easier to read than a conventional inkjet printer, and a large amount of information can be printed as a laser-printed image.

Ink contacts with the surface of the laminated retort material for packaging by forming a printing layer that can be printed by irradiating with laser light at least the inner layer of the colored ink printing layer other than the layer in contact with the contents of the packaging retort. It is possible to print without any problems, and it is possible to obtain a product having excellent hygiene without dissolving the ink printed by the oil and fat derived from the contents of the packaging laminated retort material.
Moreover, in the manufacturing process of the laminated retort material for packaging, only the same printing process as that of the ordinary printing process is performed, and it is not necessary to provide a further layer for laser printing, and the manufacturing process can be simplified.

It is a schematic sectional drawing which shows the example about the layer structure of the lamination | stacking retort material for packaging of this invention. It is a schematic sectional drawing which shows another example about the layer structure of the lamination | stacking retort material for packaging of this invention. FIG. 1 is a schematic cross-sectional view showing an example of the layer structure of a packaging retort printing body using a laminated retort material for packaging according to the present invention shown in FIG. FIG.

  The laminated retort material for packaging according to the present invention, the packaging retort body using the same, and the layer structure of those printed bodies 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 laminated retort material for packaging according to the present invention.
As shown in FIG. 1, the laminated retort material for packaging according to the present invention is laminated in the order of a base material, a pattern printing layer, and a printing underlayer, and a sealant layer on the innermost layer of the laminated structure including a gas barrier layer. A laminated retort material for packaging having a printing layer in which an area in which a pattern printing layer and a printing underlayer serving as a laser printing layer overlap each other and a printing layer in which only the printing underlayer is formed are formed In the material, the base layer for printing is basically composed of a laminated retort material for packaging, which is a white ink layer that can be colored and printed by laser light.

  In another aspect, as shown in FIG. 2, the pattern printing layer is composed of two or more layers, each of which is made of the same or different ink and has excellent adhesion to the substrate. A stacked structure may be used.

As shown in FIG. 3, the printed body of the present invention is produced by irradiating the laminated retort material for packaging of the present invention with a YAG or YVO ₄ laser from the substrate side, On the surface of the ink cartridge has a print portion in which the carbonized ink component spreads.

(Base material)
In the present invention, the substrate is a resin film according to the purpose of use, application, etc., and when the printing layer is laminated, the lamination strength with the printing base layer is higher than the lamination strength with the pattern printing layer. Any resin film that is somewhat smaller 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.

  In the present invention, examples of such resin films include various resin films such as polyolefin resins such as polyethylene resins and polypropylene resins, cyclic polyolefin resins, fluororesins, polystyrene resins, polyester resins, polyamide resins, and cellulose resins. You can choose.

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

The laminate strength and adhesion between the laser color ink layer and the substrate may be adjusted. If necessary, any surface can be subjected to a desired surface treatment before lamination. 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 a printing foundation layer and a base material, for example.
As the resin film, any of an unstretched film or a stretched film stretched in a uniaxial direction or a biaxial direction can be used.

  In the present invention, as the various resin films, for example, one or more of the various resins described above 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. Using various methods, the above-mentioned various resins can be formed into a single film, or two or more types of resins can be used and mixed before forming into a film to form a film of various resins. Further, for example, any of a stretched film stretched in a uniaxial direction or a biaxial direction using a tenter method, a tubular method, or the like can be used.

In the present invention, the thickness of the resin film may be a thickness that can be kept to the minimum necessary for strength, puncture resistance, etc., and if it is too thick, there is also a disadvantage of increasing the cost, If it is too thin, the strength, puncture resistance, etc. will decrease, which is not preferable.
In the present invention, for the reasons described above, 10 to 100 μm, preferably 10 to 50 μm is desirable.

  In the present invention, as the resin film for forming the substrate, polyethylene terephthalate (PET) and a PET substrate on which a transparent vapor deposition layer is formed can be particularly preferably used. The polyethylene terephthalate film is excellent in terms of stability, processability, cost, heat resistance, chemical resistance, etc., particularly in applications as packaging materials, and is a printing ink suitably used as a printing layer described later. When laminating, a preferable laminate strength with the printed layer can be obtained. When using PET having a transparent vapor deposition layer as a substrate, it is not necessary to provide a gas barrier layer separately, but a barrier layer may be laminated as necessary.

(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 is laminated with a commonly used color ink and laser-colored ink on a substrate by printing or coating. It is a layer provided in this way.
In the present invention, the picture print layer is formed by printing a desired print picture such as characters, figures, symbols, pictures, patterns, etc. 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 the 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 color developing material that develops color with a low-power laser beam is 1 to 99% 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 laser coloring ink layer preferably has a film thickness of 0.05 to 20 μm, more preferably about 0.1 to 7 μm. If the film thickness is less than 0.05 μm, color development or printing due to a color forming material that develops color by laser beam irradiation may be insufficient or unclear. On the other hand, as the film thickness increases, the color of the print becomes deeper. However, when the film thickness exceeds 20 μm, the color and the color of the color-developing material that develops color by laser irradiation are sufficient, but a large amount of color-developing material is used. For this reason, it is not preferable for the reasons such as cost increase to reduce the strength of the printing base layer, and the pigment color of the coloring material itself that develops color by laser beam irradiation to color the laser coloring ink layer. When the amount of pigment used is the same, the visibility of printing is slightly improved when the additive concentration is higher and the film thickness is thinner.

  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, the laser coloring is black, and the content 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 base layer preferably has a thickness of 0.05 to 20 μm, more preferably 0.1 to 7 μm. When the film thickness is less than 0.05 μm, coloring is insufficient and visibility is also insufficient. On the other hand, as the film thickness 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 decreasing the additive concentration and increasing the film thickness.

  Specific examples of the binder resin constituting the ink include urethane resin, polyester resin, acrylic resin, and cellulose resin. These resins are used alone or in combination of two or more. In particular, in a laser coloring ink used as a laser coloring ink layer, a urethane resin is preferably used as a binder resin. When the binder resin is laminated on the above-mentioned base material, it gives a preferable laminate strength with the base material, and the component of the color ink is appropriate between the base layer for printing and the base material in printing by laser light. It spreads and can be recognized as characters.

  As long as the laser coloring ink of the present invention contains a laser coloring agent, any metal oxide white ink conventionally used as a printing base can be suitably used. Such a laser coloring ink is diluted with a conventional solvent as necessary, and printed or coated on a substrate to form a printing underlayer. When the laser coloring ink contains a large amount of metal oxide, 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 order to adjust the laminate strength between the 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.

In addition, the laminate strength may be adjusted by performing a surface treatment such as corona treatment on the laminated surface of the base material, or by laminating a printing layer on an untreated surface.
The total thickness of the printed layer, the coating amount of the ink, it is preferable 1.5~4.5g / m ^2, more preferably from 2.7~3.3g / m ² The coating amount after drying. 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 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 film after printing is used in a printing system in which white ink is present, 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 part of the printing substrate. The gravure can be easily applied in large quantities, and solid printing can be performed on the entire surface or part of the printing base, thereby improving the concealment and simplifying the manufacturing process. The printing method is suitable.

In the present invention, in order to obtain a laminated retort material for packaging that is clear and does not cause printing unevenness by laser light, the coating amount of the ink is 1.5 to 4.5 g / m ² as the coating amount after drying. Is suitable.

(Gas barrier layer)
In the present invention, a metal foil or a metal oxide vapor deposition layer can be used as a barrier layer for improving the retort property. As a means for imparting the function of the barrier layer, a base film with a transparent vapor deposition layer in which a transparent vapor deposition layer of an inorganic oxide is formed on the base film layer can also be used. Further, a transparent vapor deposition layer of an inorganic oxide is formed on a laminated constitution layer different from the substrate of the laminated retort material for packaging to provide a barrier property, or a resin film having a transparent vapor deposition layer is formed between the substrate and the sealant layer. It can also be provided by laminating and arranging.

Moreover, when using metal foil, such as aluminum foil, as a barrier layer, metal foil can provide barrier property by arrange | positioning on the opposite side to the base material of a printing foundation layer.
As the barrier layer, a barrier resin coating film having barrier properties such as water vapor and oxygen, such as vinylidene chloride resin, polyvinyl alcohol resin, ethylene vinyl alcohol copolymer resin, and saponified ethylene-vinyl acetate copolymer is used. You can also

  As the inorganic oxide vapor-deposited film, a transparent thin film obtained by making a metal oxide amorphous can be used. For example, silicon (Si), aluminum (Al), magnesium (Mg), calcium (Ca), potassium (K), tin (Sn), boron (B), titanium (Ti), zirconium (Zr), yttrium (Y A transparent vapor deposition film obtained by making a metal oxide such as) amorphous (amorphous) can be used.

Examples of suitable materials for packaging materials include thin films obtained by making metal oxides such as silicon (Si) and aluminum (Al) amorphous.
The vapor deposition layer constituting the gas barrier layer of the present invention is, for example, a physical vapor deposition method (Physical Vapor Deposition method, PVD method) such as a vacuum deposition method, a sputtering method, an ion plating method, an ion cluster beam method, or the like. It can be formed using a chemical vapor deposition method (Chemical Vapor Deposition method, CVD method) such as a plasma chemical vapor deposition method, a thermal chemical vapor deposition method, or a photochemical vapor deposition method.

  In the present invention, the inorganic oxide vapor deposition film is specifically a vacuum vapor deposition method in which a metal oxide is used as a raw material, and this is heated and vapor deposited on a resin film or sheet, or a metal as a raw material. Or oxidation reaction vapor deposition method that uses metal oxide, oxidizes by introducing oxygen and deposits on resin film or sheet, plasma-assisted oxidation reaction vapor deposition method that promotes oxidation reaction with plasma, etc. Can be used to form an amorphous thin film of inorganic oxide. In the above, the heating method of the vapor deposition material can be performed by, for example, a resistance heating method, a high frequency induction heating method, an electron beam heating method (EB), or the like.

In the present invention, the thickness of the metal or metal oxide thin film layer varies depending on the type of metal or metal oxide used, but is, for example, in the range of 50 to 3000 mm, preferably in the range of 100 to 1000 mm. It is desirable to select and form arbitrarily. In the present invention, the thin film layer of metal or metal oxide may be not only one layer but also a laminated body in which two or more layers are laminated, and the metal or metal oxide to be used Can be used as a single type or a mixture of two or more types to form a thin film layer made of different materials.
For the laminated retort material for packaging of the present invention, a vapor deposition film of aluminum oxide, particularly a vapor deposition film of aluminum oxide by the PVD method can be preferably used.

(Polyamide resin layer)
As the polyamide resin film constituting the laminated retort material for packaging according to the present invention, any polyamide resin film that can hold an amorphous thin film of aluminum oxide can be used. Various polyamide-based resin films or sheets such as nylon 46, nylon 6, nylon 66, nylon 610, nylon 612, nylon 11, nylon 12, and others can be used. These polyamide resin films or sheets may be uniaxially or biaxially stretched, and the thickness is about 10 to 200 μm, preferably about 10 to 100 μm. Further, the polyamide resin film or sheet may be subjected to a surface smoothing treatment by coating the surface with an anchor coating agent or the like, if necessary.

  A method for producing a laminated material using a polyamide-based resin material will be described. Examples of such a method include a method for laminating a normal packaging material, for example, a wet lamination method, a dry lamination method, a solventless dry lamination. , Extrusion extrusion method, T-die extrusion molding method, co-extrusion lamination method, inflation method, co-extrusion inflation method, etc. In the present invention, when performing the above lamination, if necessary, pretreatment such as corona treatment and ozone treatment can be applied to the film. For example, isocyanate (urethane), polyethylene Anchor coating agents such as imine, polybutadiene, and organic titanium, or adhesives for laminating such as polyurethane, polyacryl, polyester, epoxy, polyvinyl acetate, cellulose, etc. Known pretreatments, anchor coating agents, adhesives and the like can be used.

(Sealant layer)
In the present invention, the sealant layer is provided in the innermost layer of the laminated retort material for packaging, and is a layer made of a conventional thermoplastic resin or a layer made of a film of the resin as the sealant layer.

  The sealant layer is a heat-sealable resin used for the heat-sealable resin layer, and specifically, a resin film or sheet that can be melted by heat and fused to each other can be used. Low density polyethylene, medium density polyethylene, high density polyethylene, linear (linear) low density polyethylene polymerized using a metallocene catalyst, ethylene-α / olefin copolymer polymerized using a metallocene catalyst, Polypropylene, ethylene-vinyl acetate copolymer, ionomer resin, ethylene-acrylic acid copolymer, ethylene-ethyl acrylate copolymer, ethylene-methacrylic acid copolymer, ethylene-methyl methacrylate copolymer, ethylene-propylene Copolymer, methylpentene polymer, polybutene polymer, polyethylene or polymer Polyolefin resins such as pyrene modified with unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, itaconic acid, polyvinyl acetate resins, poly (meta ) Acrylic resins, polyvinyl chloride resins, and other resins can be used alone or in admixture of two or more.

  Among the heat-sealable resins that make up the above sealant layer, those in which linear (linear) low-density polyethylene is polymerized using a single site catalyst such as a metallocene catalyst have a narrow molecular weight distribution and are copolymerized. Since the ratio is also stable, in addition to heat seal stability, it is excellent in content resistance, stress cracking resistance, low-temperature heat sealability, hot sealability, and the laminated retort material for liquid packaging of the present invention It can be suitably used for the sealant layer.

  In addition to the above-mentioned linear (linear) low density polyethylene, the heat seal resin layer includes CPP (unstretched polypropylene), LDPE, depending on the contents to be filled, the heat treatment after filling, the distribution conditions, and the like. Select an appropriate film or extruded coating layer such as ethylene / α-olefin copolymer, ethylene / vinyl acetate copolymer, ethylene / acrylic acid copolymer, ethylene / acrylic acid ester copolymer, ionomer, and polyester resin. Can be used.

In the use as a packaging material, when it becomes the innermost layer in contact with the contents, polyolefin resins such as polyethylene and polypropylene are preferably used. In particular, in the retort material of the present invention, unstretched polypropylene is used as the sealant layer.

  Although the lamination | stacking method of a sealant layer is not specifically limited, It can laminate | stack by extrusion-coating the thermoplastic resin which forms a sealant layer on a printing layer. Further, the film made of the thermoplastic resin may be laminated by a dry lamination method or a sandwich lamination method.

  As an adhesive for dry lamination, urethane adhesive, polyester polyurethane adhesive, polyester adhesive, polyether adhesive, vinyl adhesive, acrylic adhesive, epoxy adhesive, and the like can be used. . Further, any thermoplastic resin can be used as the adhesive resin for sandwich lamination.

In the present invention, the sealant layer can be formed by using the heat sealable resin as described above and extruding and laminating by an extrusion laminating method or the like.
In the present invention, the thickness of the sealant layer can be appropriately set according to the content filled in the laminated retort material for packaging, but is preferably about 20 to 200 μm, more preferably 50 to 100 μm.

Moreover, you may provide a primer coat layer, an undercoat layer, an anchor coat layer etc. between the polyamide-type resin layer and a sealant layer, for example.
As the anchor coat layer constituting the laminated retort material for packaging of the present invention, either a solvent type or an aqueous type can be used.

  Therefore, (chlorinated) polypropylene, modified polyolefin, ethyl vinyl alcohol, polyethylene imine, polybutadiene, polyurethane, polyester polyurethane emulsion, polyvinyl chloride emulsion, urethane acrylic emulsion, silicon acrylic emulsion, vinyl acetate acrylic emulsion , Acrylic emulsion, styrene-butadiene copolymer latex, acrylonitrile-butadiene copolymer latex, methyl methacrylate-butadiene copolymer latex, chloroprene latex, polybutadiene latex rubber latex, polyacrylate latex, polyacrylate Vinylidene chloride latex, polybutadiene latex, or carboxyl modification of these latexes And water-soluble substances such as polyvinyl alcohol, water-soluble ethylene-vinyl acetate copolymer, polyethylene oxide, aqueous acrylic resin, aqueous apoxy resin, aqueous cellulose derivative, aqueous polyester and aqueous lignin derivative, etc. An emulsion or dispersion anchor coat agent is used. For example, when the outermost layer is a polyethylene-based melt-extruded resin layer, a polyethylene-based or modified polyolefin-based emulsion or dispersion is preferable in consideration of adhesiveness to the substrate.

(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 substrate side of the laminated retort material for packaging, the transparent vapor-deposited film provided on the substrate in the laminated retort material for packaging can pass even with a low output of the laser beam, so The ink component of the printing layer is colored and discolored while reaching the base layer without disturbing the formation of the printed image and minimizing the damage to the film. In this way, a color development region can be formed on the surface of the printing underlayer so that a laser-printed image can be efficiently formed. Then, by forming the laser print image on the surface of the laser coloring ink layer, an image having excellent visibility from the substrate side can be obtained.

In the present invention, the pulse conditions for performing such printing are, for example, an average output of 0.8 to 5.0 W, more preferably 1.0 to 2.0 W in a YVO ₄ laser machine (MD-V9600 manufactured by Keyence). Pulse conditions with a Q switch frequency of 10 to 30 KHz and a scan speed of 300 to 4000 mm / s, more preferably 1500 to 3000 mm / s are used. By performing printing under these conditions, high-speed printing can be performed without making a hole in the packaging laminated retort material, and a clear printed image can be obtained.

(Printed body with laser light)
In the printing process on the laminated retort material for packaging according to the present invention, even if the average output of the laser is set low or the scan speed is set high, a clear print image, for example, a thick and clear character is printed. be able to.

  In the printed body of the present invention, the diameter of the color development region formed between the substrate and the printed layer by laser spot irradiation is desirably 40 μm to 1 mm, more preferably 400 to 700 μm. The colored ink component spreads in this color development region, and a clear printed image can be obtained by using the white ink of the printing base 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.
The packaging retort material for packaging and the packaging retort printing material obtained by printing on the packaging retort material of the present invention can be suitably applied to the packaging material for retort as a printed material having a laminated structure having the retort resistance of the present invention. it can.

  In the laminated retort material for packaging according to the present invention, the printing layer is one that performs color printing on a region consisting only of colored white ink that functions as a printing base layer that can be colored and printed by laser light. The area where the pattern printing layer with the desired color printing layer and the printing base part overlapped, which is not subjected to printing, has adhesion to the substrate even in an atmosphere under wet heat, has high lamination strength, and is laminated for packaging. In combination with the fact that no peeling occurs as a retort material, it is possible to reliably obtain a print with a clear coloring area in the print area.

(Retort body for packaging)
A packaging retort body using the above-described laminated retort material for packaging will be described. The bag-shaped container body made of a packaging retort body uses a laminated material made of the above-described laminated retort material for packaging, folds this laminated material, and stacks the heat-sealable resin layers facing each other. The package can be manufactured by heat-sealing the end portion to form a cylindrical package, then sealing the bottom to fill the contents, and further sealing the top.

  As the bag making method, the laminated material as described above is folded or overlapped so that the inner layer faces each other, and the peripheral end thereof is, for example, a side seal type, a two-side seal type, a three-side seal. Various types of heat seals such as molds, four-sided seals, envelope stickers, pillow seals, pleated seals, flat bottom seals, square bottom seals, gussets, etc. A packaging retort in the form can be produced. 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.

EXAMPLES The present invention will be specifically described below with reference to examples, but these do not limit the present invention.
[Example 1]
A pattern printing layer of color ink was applied to one surface of a 12 μm thick PET film by a gravure roll coating method using color ink. On top of that, a laser coloring ink containing 5% by weight of bismuth oxide (in terms of the solid content of the ink composition) as a coloring material and 15% by weight of titanium dioxide as a white ink pigment was applied to the entire surface by a gravure roll coating method. A color ink printing layer was provided. Next, an adhesive layer is provided on the printed layer by a dry lamination method (DL) using a two-component curable polyester-based adhesive, an aluminum foil having a thickness of 9 μm is laminated, and then a two-component curable type An adhesive layer is provided by the DL method using a polyester polyurethane-based adhesive, and a biaxially stretched polyamide (nylon) film having a thickness of 15 μm and an unstretched polypropylene film sealant layer having a thickness of 50 μm are sequentially laminated by the DL method. did. Thereby, the PET film of the present invention / pattern color ink printing layer / laser color ink printing layer / adhesive layer / AL (barrier layer) / adhesive layer / biaxially stretched polyamide film / adhesive layer / unstretched polypropylene film sealant A laminated retort material for packaging having a layer structure of layers was obtained.

[Example 2]
On the vapor deposition layer side of a polyethylene terephthalate film (base material) having a thickness of 12 μm and provided with a transparent aluminum oxide vapor deposition layer by PVD, as in Example 1, using color ink and laser color ink by gravure roll coating method Then, a pattern printing layer and a color ink printing layer were sequentially applied to provide a gravure printing layer. Next, a biaxially stretched polyamide (nylon) film having a thickness of 15 μm and an unstretched polypropylene film sealant layer having a thickness of 50 μm are respectively formed on the printed layer by a DL method using a two-component curable polyester adhesive. The layers were sequentially laminated. Thus, a laminated retort for packaging having the layer configuration of the PET film / pattern color ink printing layer / laser color ink printing layer / adhesive layer / biaxially stretched polyamide film / adhesive layer / unstretched polypropylene film sealant layer of the present invention. The material was manufactured.

[Examples 3 and 4]
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. Except for the printing layer, the same as in Example 1 or 2, respectively, PET film of the present invention / pattern color ink printing layer / laser coloring ink printing layer / adhesive layer / AL (barrier layer) / adhesive layer / Laminated retort packaging material having a layer structure of biaxially stretched polyamide film / adhesive layer / unstretched polypropylene film sealant layer, or PET film / pattern color ink printing layer / laser color ink printing layer / adhesive layer / biaxial stretching A laminated retort material for packaging having a layer structure of polyamide film / adhesive layer / unstretched polypropylene film sealant layer It was.

[Comparative Example 1]
Instead of the laser coloring ink in Example 1, CLIOS (urethane-based resin binder) manufactured by DIC Graphics Co., Ltd. and white ink of Lamic FB701 white (D) (urethane-based resin binder) manufactured by Dainichi Seika Kogyo Co., Ltd. were used. In the same manner as in Example 1, PET film / pattern color ink printing layer / laser ink printing layer / adhesive layer / AL (barrier layer) / adhesive layer / biaxially stretched polyamide film / adhesive layer / none A laminated retort material for packaging having a layer structure of a stretched polypropylene sealant layer was produced.

[Comparative Example 2]
Instead of using laser coloring ink in Example 2, CLIOS (urethane-based resin binder) manufactured by DIC Graphics Corporation and white ink of Lamic FB701 white (D) (urethane-based resin binder) manufactured by Dainichi Seika Kogyo Co., Ltd. were used. In the same manner as in Example 2, for packaging having a layer structure of PET film / pattern color ink printing layer laser ink printing layer / adhesive layer / biaxially stretched polyamide film / adhesive layer / unstretched polypropylene sealant layer A laminated retort material was produced.

[Laser printing method]
For each of the packaging retort materials for packaging obtained in Examples 1 to 4 and Comparative Examples 1 and 2, YVO ₄ laser light was irradiated from the base material side under the following conditions to form a laser print image to obtain a printed body. Obtained.
-Laser irradiation conditions YVO ₄ laser machine (MD-V9600 manufactured by Keyence Co., Ltd.) For the examples, the average output is 1.6 W, the Q switch frequency is 10 kHz, the scan speed is 2000 mm / s, and the comparative example is the average output is 4.0 W. Q switch frequency 10KHz, scan speed 500mm / s.

(Evaluation method)
For each packaged retort material for packaging in the laminated configuration of Examples 1 to 4, the expiration date is printed on the laser color ink base layer by actually irradiating the laser beam, and the visibility of the characters printed there, Printed characters such as thickness of retention and color density were judged comprehensively, the printed state was evaluated by visibility, and the appearance after laser irradiation was confirmed.

[Evaluation]
For the laser printed image obtained under the above laser irradiation conditions, the printed state was evaluated by visibility, and the appearance after laser irradiation was confirmed. In the laminated retort material for packaging of the laminated structure of Examples 1 to 4, Even when printing with low-power laser irradiation (1.6 W, scan speed 2000 mm / s), the print density is high, and it does not disappear even if it is rubbed. was gotten. In particular, the system in which the copper / molybdenum composite oxides of Examples 3 and 4 were added showed a color development superior to the system of the color developing material alone, and the copper / molybdenum composite oxide serves as the color developing material and further functions as a color developing aid. Laser printing with good properties and good visibility was obtained.

  On the other hand, in the laminated retort materials for packaging of Comparative Examples 1 and 2, when laser irradiation conditions were performed at a low output, even when laser irradiation was performed on the laser ink layer, printing with good visibility was not obtained. Therefore, when irradiation was performed at a high output (4.0 W, scan speed 500 mm / s) so that sufficient visibility was obtained, color was developed and visibility printing was obtained. However, the printing was blurred, the packaging material was damaged, the visibility was inferior, and the proper printing range was narrow.

1. Base material 2. 2. Transparent vapor deposition layer Print layer 3a. Pattern printing layer 3b. 3. Print base layer 4. Metal foil 5. Polyamide layer Sealant layer Print section

Claims (9)

Laminating retort material for packaging, which is laminated in the order of base material, pattern printing layer, printing base layer, polyamide resin, sealant layer, and has a gas barrier layer, under which printing pattern layer and laser printing layer become In the laminated retort material for packaging having a printed layer in which the region where the base layer overlaps and the region of only the base layer for printing are formed,
The packaging underlayer is a laminated retort material for packaging, which is a color developing ink layer that can be printed by laser light including a color developing material that develops color when irradiated with laser light.   The laminated retort material for packaging according to claim 1, wherein the coloring material is a bismuth compound.   The laminated retort material for packaging according to claim 2, wherein the bismuth compound is one or more compounds selected from bismuth hydroxide, bismuth oxide, bismuth carbonate and bismuth nitrate.   The laminated retort material for packaging according to any one of claims 1 to 3, wherein the color ink contains one or more compounds selected from a metal oxide or a composite oxide or a group thereof.   The laminated retort material for packaging 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 laminated retort material for packaging according to any one of claims 1 to 5, wherein the gas barrier layer is a gas barrier transparent vapor deposition layer and is a transparent vapor deposition film having a gas barrier transparent vapor deposition layer on a substrate. .   The laminated retort material for packaging according to any one of claims 1 to 5, wherein the gas barrier layer is an aluminum metal layer and is located on the side opposite to the substrate of the printing base layer.   The packaging retort body using the lamination | stacking retort material for packaging of any one of Claims 1-7. The ink which developed by irradiating the laminated retort material for packaging according to any one of claims 1 to 7 or the retort body for packaging according to claim 8 with YAG or YVO ₄ laser light from the substrate side. A retort laser-printing body for packaging having a laser-printed image in which a color-developing area of the composition extends to the boundary between the base material and the base layer for printing.

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