JP5382301B2 - Easy-open retort packaging - Google Patents

Description

  The present invention relates to an easily openable retort package that has retort aptitude and is excellent in straight openability and can be easily opened by hand.

  Conventionally, as a package for retort, for example, a film-like laminate of PET (or OPP) / ON / Al foil / CPP (or LLDPE) is generally used from the surface side. Here, the surface layer is a biaxially stretched polyethylene terephthalate (PET) film or a biaxially stretched polypropylene (OPP) film, the barrier layer is an aluminum foil (Al foil), the inner surface heat seal layer is unstretched polypropylene (CPP) or Linear low density polyethylene (LLDPE) and biaxially stretched nylon (ON) for improving impact resistance and self-supporting property (standing up) are used as an intermediate support layer.

  In such a retort package, even if the package is torn linearly by hand to take out the contents, in a package having conventional biaxially stretched nylon (ON) as an intermediate support layer, Even if a notch is provided, there is a problem in that tearing is not performed linearly at the time of opening, and the tearing position is shifted between the front side laminated material and the back side laminated material, resulting in tearing in a crotch tear state. Moreover, in order to prevent bag breakage during retort and bag breakage during distribution, the thickness of unstretched polypropylene as the heat seal layer is 50 μm or more, and the total thickness is 80 μm or more. If it is thick, opening by hand becomes difficult.

  However, in retort packaging, it is often required to be opened easily by hand, and straight openability is often required, and a stretched high-density polyethylene layer or biaxially stretched special nylon with improved straight tearability during the construction of the laminate. Although it is known to use a film (Patent Documents 1 and 2), it has the disadvantages of deteriorating the physical properties of the packaging material and increasing the price. In addition, the biaxially stretched polyethylene terephthalate film (PET) layer, which is the surface layer, and the biaxially stretched nylon (ON) layer, which is the intermediate support layer, are made with a plurality of cuts before the laminate is produced, Although there is a method of making a cut or the like (Patent Document 3), there is a problem that it is difficult to accurately align the cuts during the stacking operation.

On the other hand, in a refill detergent pouch, it is known to perform half-cutting with a laser to form an opening portion. However, since it is difficult to control so that only the surface layer is cut by laser drilling operation, the intermediate support layer is also partially cut, and in the pouch for retort, hot water from the retort is used. The aluminum ground is corroded and the barrier property is impaired, and there is a high risk that pinholes are generated, and there is no example in which this method is adopted as an opening portion in a retort pouch.
JP-A-8-80977 JP 2003-236972 A JP-A-11-77872

  In the present invention, when forming the opening portion in the retort pouch by laser irradiation, the range of the half cut can be accommodated without affecting the intermediate support layer, and physical property deterioration of the laser irradiation portion can be prevented even during the retort operation. At the same time, an object of the present invention is to provide an easy-open retort package that is excellent in straight openability of the opening portion.

The easy-open retort packaging body of the present invention is laminated in the order of at least a surface layer, a laser reflective ink layer, an intermediate support layer, a barrier layer, and a heat seal layer, and a printed layer between the surface layer and the laser reflective ink layer. And a film-like laminate having a laser absorber layer are superposed with the surface layer side being the outside and the heat seal layer side being the content side, the peripheral edge portion being heat-sealed, and the superposed film-like laminate being In a packaging bag provided with an opening part that can be torn open by hand, the film-like laminate in the opening part is irradiated with laser from the surface layer side in front of the laser reflective ink layer from the surface layer side in the cross-sectional direction. It is half-cut until the opening part is imparted with straight openability.

  Said laser reflection ink layer is a metallic ink layer containing 3-10 mass% of metal powder.

  The metal powder is a leafing type aluminum powder.

  A printing layer is provided between the surface layer and the laser reflecting ink layer.

  Said printing layer contains a laser absorber, It is characterized by the above-mentioned.

  Each of the laser reflective ink layer, the intermediate support layer, the barrier layer, and the heat seal layer is laminated using a laminating adhesive.

  In the easily openable retort packaging body of the present invention, when the opening portion of the retort pouch is formed by a laser, laser irradiation can be reflected by the laser reflecting ink layer, so that the intermediate support layer is not damaged. Therefore, physical property deterioration of barrier layers, such as Al foil in a laser irradiation part, can be prevented in the case of a retort, and it can be excellent in the straight openability at the time of opening by the half cut in a tear line.

  The easy-open retort package of the present invention will be described with reference to the drawings. FIG. 1 is a front view showing an example of the easy-open retort package of the present invention, and FIG. 2 is a cross-sectional view showing the layer structure of the film-like laminate in the easy-open retort package of the present invention. Moreover, FIG. 3 is a schematic diagram for demonstrating the cross-sectional state of the tear line in the easily openable retort packaging body of this invention.

  In the figure, 1 (1a, 1b) is a film-like laminate, 2 is a side seal portion, 3 is an upper seal portion, 4 is a bottom seal portion, 5 is a notch, 6 is a cut-out portion, and 10 is an easily openable retort packaging. Body, 11 is a surface layer, 12 is a printing layer, 13 is a laser reflecting ink layer, 14 is an intermediate support layer, 15 is a barrier layer, 16 is a heat seal layer, 17 is an adhesive layer, and 18 is a half-cut portion.

  First, the easy-open retort packaging body 10 shown in FIG. 1 has two film-like laminates 1a and 1b stacked with the surface layer as the outside and the heat seal layer as the inside, and the three sides are heat-sealed 2, 2 After the contents are stored, the upper seal 3 is provided, and the package 10 is provided with notches 5 and 5 for opening the side seal portions 2 and 2 in the vicinity of the upper seal 3. In addition, a cutout portion 6 starting from the notches 5 and 5 is provided.

Next, the film-shaped laminated body 1 (1a, 1b) in this invention shown by FIG. 2, FIG. 3 is demonstrated.
Examples of the surface layer 11 in the film-like laminate include polyester films such as polyethylene terephthalate film (PET) and polybutylene terephthalate film, and polyamide films such as polypropylene film (PP), 6-nylon film, and 6,6-nylon film. Is done. In general, those having improved heat resistance and impact resistance by biaxial stretching are used. In addition, it uses a polyester film or nylon film that has a straight cut in the film flow direction (MD), and has a surface layer that matches the MD direction with the cut-off direction. And can. The thickness of the surface layer (film) is 5 to 20 μm.

  A printing layer 12 is provided on the front surface (not shown) and / or the back surface of the front surface layer 11. As the ink to be used, a heat resistant water gravure ink having a normal two-component curable urethane resin as a main color change material and a pigment having excellent heat resistant water as a colorant can be used, and printing such as gravure printing is performed. In order to impart printability, the surface of the film forming the surface layer may be subjected to corona treatment.

  Moreover, it is good to contain a laser absorptive pigment | dye in printing ink. As a laser-absorbing dye, although it depends on the oscillation wavelength range of laser light, if the wavelength range is a near-infrared region centered on, for example, 800 nm, it has heat-resistant water and is a harmless inorganic compound or near-infrared absorption. It is preferable to include a coloring matter in the printing ink, the laser irradiation portion can be made excellent in laser absorbability, and the half cut portion can be efficiently formed. The laser absorbing dye layer may be printed on the printing layer 12 using a laser absorbing dye ink.

Next, the laser reflecting ink layer 13 that characterizes the present invention will be described. Laser reflective ink layer, an aluminum foil 3 to 10 wt% having a thickness foils area at 0.5μm or less containing aluminum foil fragments leafing type 20μm ² ~2000μm ² to 75%, preferably from 3 wt% to 7 It is a metallic ink containing mass%. The ink contains 15 to 200 parts by mass of a transparent binder resin such as polyester resin, poly (meth) acrylic acid ester, vinyl chloride, polyurethane, and epoxy resin with respect to 100 parts by mass of the aluminum foil. Examples of the solvent include esters, ethers, ketones, and aromatic hydrocarbons, and the viscosity of the ink is preferably 50 to 1000 cps (20 ° C., BM type rotational viscometer). The laser reflection ink may be formed in a film thickness of 0.1 μm to 1 μm, preferably 0.2 μm to 0.5 μm, at least in a portion where the cut line portion 6 is formed in the film-like laminate by gravure printing.

  When the laser reflecting ink is applied and formed on the printed layer by setting the aluminum foil to a concentration of 3 to 10% by mass, the leafing-shaped aluminum foil pieces are arranged and laminated so as to be folded on the printed layer, It can be mirror-finished and has excellent laser reflectivity. When the concentration of the aluminum foil is high, the specularity is lowered and the laser reflectivity is lowered, which is not preferable.

  The intermediate support layer 14 is a normal biaxially stretched nylon film (ON), but in the same way as the above-mentioned surface layer, a nylon film having a linear cut property in the film flow direction (MD) is used to determine the MD direction. The cutting direction of the packaging bag may be made coincident, and it can be made more excellent by the straight openability at the time of opening. The ON film is slightly less rigid than the PET film and has a hygroscopicity of about 7%. On the other hand, it is excellent in mechanical strength such as bending strength, piercing strength, impact strength, and tensile strength, especially at low temperatures. Since it is excellent in physical properties, it is possible to obtain a laminated film having excellent performance by complementing each other's weak points by using and combining PET films as the surface layer. The thickness of the ON film 14 is 10 μm to 40 μm, preferably 13 μm to 30 μm.

  As the barrier layer 15, an aluminum foil having a thickness of 5 μm to 9 μm is generally used as the oxygen barrier layer, but a film on which an inorganic substance such as aluminum, alumina oxide, silicon oxide or the like is vapor-deposited may be used.

  Any heat seal layer 16 may be used as long as it can withstand retort processing and can be melted by heat and fused to each other. Specifically, for example, a low density polyethylene film, a medium density polyethylene film, a high density polyethylene film, a linear low density polyethylene film, a polypropylene film, an ethylene-vinyl acetate copolymer resin film, an ionomer resin film, an ethylene-acrylic acid copolymer. Polymer resin film, ethylene-ethyl acrylate copolymer resin film, ethylene-methacrylic acid copolymer resin film, ethylene-propylene copolymer film, methylpentene resin film, polybutene resin film, acid-modified polyolefin resin film, etc. Can be used. The thickness of the film is 10 μm to 300 μm, preferably 20 μm to 100 μm.

  In the present invention, it is particularly preferable to use an unstretched polypropylene resin film having excellent retort resistance as the heat seal layer. In particular, an unstretched polypropylene resin film having a melting point of 145 ° C. to 165 ° C. is preferably used for a high retort (HTST) of 120 ° C. or higher. Specifically, it is preferable to use a film made mainly of an ethylene-propylene copolymer and formed from a resin such as a propylene-ethylene random copolymer or a propylene-ethylene block copolymer. An unstretched polypropylene-based resin film obtained by adding a olefin rubber component to this, optionally adding a desired additive, and kneading the composition sufficiently, for example, by extrusion, is preferable. .

In addition, the above-mentioned laser reflective ink layer, an intermediate support layer such as a polyamide resin film, a barrier layer such as an aluminum foil, and each layer of a heat seal layer are formed by a dry lamination method, a wet lamination method, an extrusion lamination method, or the like. Although it is good to laminate | stack by combining a method, a dry lamination method is preferable especially, and the polyester polyurethane type adhesive agent is used preferably as an adhesive agent in this case. Coating amount is used in the range of 0.5g / m ² ~10g / m ² in a dry state, preferably 1 to 5 g / m ² in consideration of the tear. The polyester polyurethane adhesive layer is preferable because it has little elongation and can be easily torn following each film constituting the laminate. Moreover, since it is excellent in heat resistance, it is an adhesive suitable for a retort packaging bag. The tear strength of the laminate is preferably 100 g or less when the tear strength is measured according to JIS P8116.

  For example, as shown in FIG. 1, the film-like laminate obtained in this manner is overlapped with two heat seal layers on the inside, and then heat-sealed around three sides to form a bag. Next, notches 5 and 5 are formed on the upper part of the pouch, and laser may be used to irradiate the laser between the notches 5 and 5 in a straight line, for example, on the front and back of the flat bag. Can be made. In the present invention, for example, after the three-way pouch is formed, the cut portions 6 are linearly formed between the front and back notches by laser irradiation, so that there is no deviation between the front and back and excellent linear tearability. The shape of the half cut in the irradiation unit may be a dotted line or a straight line.

  In addition, since the laser beam is reflected by the laser reflecting ink layer, it is cut in the cross-section direction from the outside to the front of the laser reflecting ink layer, preventing the influence on the intermediate support layer and the barrier layer, and maintaining the retort suitability. . And after accommodating the contents in a three-way pouch, the upper seal part is heat-sealed to obtain the easy-open retort package of the present invention.

  The easy-open retort package of the present invention is not limited to a flat bag such as a four-side sealed bag or a pillow type bag, a self-standing bag such as a standing pouch, and any type of bag such as a gusset bag. Can be applied.

Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples.
(Example)
A white ink ("Krios White" manufactured by The Inktec Co., Ltd.) with a dry film thickness of 1 μm is printed on one side of a 12 μm thick PET film (“E5100” manufactured by Toyobo Co., Ltd.), and then the printed surface is metallic. The ink (containing 10% by mass of leafing type aluminum piece, “CLIS-silver” manufactured by The Inktec Co., Ltd.) was diluted to 6% by mass of aluminum piece, and then gravure-printed with a dry film thickness of 1 μm.

After applying 4 g / m ² (dry state) of polyester polyurethane adhesive (“Takelac A515 / A-50” manufactured by Takeda Pharmaceutical Co., Ltd.) to the metallic printed surface of the obtained PET printed matter, ONBC having a thickness of 15 μm A laminated film was obtained by laminating a -RT (ON) film (manufactured by Unitika Ltd.) by a dry lamination method.

  Next, a 7 μm thick aluminum (AL) foil is laminated on the ON film surface of the laminated film by the dry lamination method using a polyester polyurethane adhesive in the same manner as described above, and the polyester polyurethane is similarly coated on the Al foil surface. An unstretched polypropylene (CPP) film (“ZK93K” manufactured by Toray Film Processing Co., Ltd.) having a thickness of 70 μm was laminated by a dry lamination method using a system adhesive to obtain a film-like laminate having the following specifications.

  PET film (film thickness 12 μm) / printing layer (1 μm) / metallic printing layer (1 μm) / adhesive layer / ON film (15 μm) / adhesive layer / AL foil (7 μm) / adhesive layer / unstretched CPP film ( 70 μm).

(Comparative example)
In producing the film-like laminate in the examples, a film-like laminate having the following specifications was obtained in the same manner as in the examples except that the metallic ink layer was not provided.

  PET film (12 μm) / printing layer (1 μm) / adhesive layer / ON film (15 μm) / adhesive layer / AL foil (7 μm) / adhesive layer / unstretched CPP film (70 μm).

  Using the film-like laminates obtained in Examples and Comparative Examples, respectively, with the unstretched CPP film side as the inner surface, a 130 mm × 170 mm three-way pouch in the shape of FIG. 1, and a notch 5 at a location 30 mm above the pouch, 5 was applied.

  Between the notches 5 and 5 of the obtained three-way pouch, carbon dioxide laser (Keyence L-Z9510) 30 W (output 50%), scanning speed 1500 mm / sec, irradiation diameter 0.4 mm, laser irradiation is linear and the pouch It was applied on both sides.

  When the perforation pattern (cross section) in the three-sided pouches obtained in Examples and Comparative Examples was observed, the PET layer and the printing layer up to the front of the metallic ink layer were perforated in the Example, and the influence on the ON layer was recognized. However, in the comparative example, it was found that the PET layer and the printing layer were perforated, and the ON layer was perforated to 2/3 proper in the film thickness direction.

  Next, the bags obtained in the examples and comparative examples were each torn and opened from the notch portion by hand. The straight openability was good, but the three directions obtained in the examples and comparative examples. After the pouch was filled with 220 cc of water, the upper part of the pouch was heat sealed.

  Then, a drop test was performed with the notch portion down. When vertically dropped from a height of 120 cm 30 times, the bag obtained in the example was dropped 30 times but did not break, but the bag obtained in the comparative example was notched when dropped 12 times. Cutting from the part occurred.

  INDUSTRIAL APPLICABILITY The present invention is suitable for an easily openable retort package that has retort suitability and is excellent in straight openability and can be easily opened by hand.

FIG. 1 is a front view showing an example of an easily openable retort package of the present invention. FIG. 2 is a cross-sectional view showing the layer structure of the film-like laminate in the easy-open retort packaging of the present invention. Drawing 3 is a mimetic diagram explaining the section state in the film-like layered product of the tear line part of the easy-open retort packaging of the present invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 (1a, 1b) ... Film-like laminated body, 2 ... Side seal part, 3 ... Top seal part, 4 ... Bottom seal part, 5 ... Notch, 6 ... Cut-off part, 10 ... Easy-open retort packaging, 11 ... surface layer, 12 ... printed layer, 13 ... laser reflective ink layer, 14 ... intermediate support layer, 15 ... barrier layer, 16 ... heat seal layer, 17 ... adhesive layer, 18 ... half-cut portion

Claims (6)

At least a surface layer, a laser reflective ink layer, an intermediate support layer, a barrier layer, and a heat seal layer are laminated in this order, and a film-like laminate having a printing layer and a laser absorbent layer between the surface layer and the laser reflective ink layer However, the surface layer side is the outside, the heat seal layer side is superimposed as the contents side, the peripheral edge is heat sealed, and the unsealed portion where the superimposed film-like laminate can be teared open by hand In the provided packaging bag, the film-like laminate in the opening part is half-cut from the surface layer side to the laser reflective ink layer in the cross-sectional direction by laser irradiation from the surface layer side, and straight opening to the opening part Is an easily openable retort package. The easily openable retort package according to claim 1, wherein the laser reflective ink layer is a metallic ink layer containing 3 to 10% by mass of metal powder. The easily openable retort packaging body according to claim 2, wherein the metal powder is a leafing type aluminum powder. The easily openable retort packaging body according to claim 1, further comprising a printing layer between the surface layer and the laser reflective ink layer. The easily openable retort packaging body according to claim 4, wherein the printed layer contains a laser absorber. The easily openable retort packaging body according to claim 1, wherein each of the laser reflective ink layer, the intermediate support layer, the barrier layer, and the heat seal layer is laminated using an adhesive for laminating.

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