Laminated film for packaging

Abstract

To provide a laminated film for packaging that enables high-speed operation of filling and packaging machines and improves productivity of packaging bags.SOLUTION: A laminated film for packaging is used for filling and packaging machines equipped with heat sealing means. The film has at least a base layer and a sealant layer. The sealant layer consists of at least two layers, and one or more of the sealant layers, other than the outermost sealant layer, contains inorganic filler.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a packaging laminate film for use in a filling and packaging machine equipped with a heat sealing means, and more particularly to a packaging laminate film that has excellent heat sealing properties and allows high-speed filling. [Background technology]

[0002] Conventionally, a vertical filling and packaging machine as disclosed in Patent Document 1 has been known as an apparatus for continuously manufacturing packages by forming a long, flexible laminated packaging film into a bag shape and filling and packaging liquids, viscous substances, such as food and beverages, liquid seasonings, medicines, cosmetics, or powders, granular substances, or other packaged items. This vertical filling and packaging machine includes a pair of vertical sealing rolls that fold a strip-shaped laminated packaging film in two at the center position in the width direction and continuously seal the overlapping side edges in the running direction of the laminated packaging film to form a cylinder, and a pair of horizontal sealing rolls that seal the cylindrical laminated packaging film over its entire width at regular intervals while filling it with the packaged items, thereby forming horizontal seals. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2005-96849 A Summary of the Invention [Problem to be solved by the invention]

[0004] The laminated packaging film used in such a vertical filling and packaging machine usually comprises a base layer and a sealant layer, and is folded in two at the center in the width direction so that the sealant layers face each other. The laminated packaging film folded in two is sandwiched between a pair of vertical sealing rolls and a pair of horizontal sealing rolls, and is heated and pressurized to fusion-bond (heat seal) the facing sealant layers to form vertical and horizontal seal portions, thereby continuously forming a packaging bag.

[0005] When a vertical filling and packaging machine is operated at high speed, a pair of vertical sealing rolls and a pair of horizontal sealing rolls must apply an extremely high temperature from the outermost layer side (base material layer side) to melt and fuse-bond the sealant layers located in the innermost layers and facing each other. However, doing so can cause thermal damage to the packaging laminate film, and there is a risk of a decrease in quality, such as wrinkles and bubbles occurring in the sealed areas.

[0006] For this reason, in the past, the filling speed was reduced and the heating time was extended to allow the heat sealing temperature to be set over a wide range, but this method reduced the productivity of packaging bags and left room for improvement.

[0007] The present invention is intended to solve the problems associated with the prior art, and has an object to provide a laminated film for packaging that enables high-speed operation of a filling and packaging machine and improves the productivity of packaging bags. [Means for solving the problem]

[0008] The laminated packaging film of the present invention is a laminated packaging film used in a filling and packaging machine equipped with a heat sealing means, and is characterized in that it comprises at least a base layer and a sealant layer, the sealant layer having at least a two-layer structure, and at least one of the sealant layers other than the outermost sealant layer contains an inorganic filler.

[0009] In the packaging laminate film of the present invention, (1) The inorganic filler is at least one compound selected from calcium carbonate, silica, talc, zeolite, titanium oxide, alumina, zinc oxide, magnesium oxide, boron nitride, and aluminum nitride; (2) the content of the inorganic filler is 4% by weight to 40% by weight of the entire sealant layer; is the more preferred solution. Effect of the Invention

[0010] In the packaging laminate film according to the present invention, the sealant layer has at least a two-layer structure, and at least one of the sealant layers other than the outermost sealant layer contains an inorganic filler with high thermal conductivity or thermal diffusivity, so that heat from the heat sealing means (such as a heat sealing roll) can be efficiently transferred to the sealant layer. As a result, the temperature range when the packaging laminate film is heat-sealed by the heat sealing means can be expanded, and high-speed operation becomes possible, thereby improving productivity. [Brief description of the drawings]

[0011] [Figure 1] 1 is a cross-sectional view showing one embodiment of a packaging laminate film according to the present invention. [Diagram 2] FIG. 1 is a diagram showing a vertical filling and packaging machine as an example of a filling and packaging machine. [Diagram 3] FIG. 2 is a cross-sectional view of a packaging laminate film used in the examples. [Figure 4] FIG. 2 is a graph showing the relationship between heat sealing temperature and heat sealing strength in the examples. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. Fig. 1 is a cross-sectional view showing one embodiment of the packaging laminate film according to the present invention, Fig. 2 is a diagram showing a vertical filling and packaging machine as an example of the filling and packaging machine.

[0013] 1, reference numeral 1 denotes a packaging laminate film, reference numeral 2 denotes a base layer, reference numeral 3 denotes an intermediate layer, and reference numeral 4 denotes a sealant layer, and the sealant layer 4 has a two-layer structure consisting of a first sealant layer 4a located on the intermediate layer 3 side and a second sealant layer 4b located on the outermost layer. In this embodiment, the intermediate layer 3 is provided between the base layer 2 and the sealant layer 4, but the intermediate layer 3 is not essential and may be laminated as appropriate.

[0014] The packaging laminate film 1 can be formed by sequentially laminating the first sealant layer 4a and the second sealant layer 4b to a required thickness using a tandem extrusion laminator, or by co-extrusion laminating the resins constituting each layer, onto the base layer 2 or onto a laminate film consisting of the base layer 2 and the intermediate layer 3. Alternatively, the first sealant layer 4a and the second sealant layer 4b may be formed in advance by a cast molding method, an inflation molding method, or the like, and then laminated onto the base layer 2 or onto a laminate film consisting of the base layer 2 and the intermediate layer 3 by a dry lamination method, an extrusion lamination method, or the like.

[0015] Incidentally, the packaging laminate film 1 is used in a filling and packaging machine having a heat sealing means, and can be suitably used in, for example, the vertical filling and packaging machine shown in Fig. 2. The filling and packaging machine may be a vertical pillow filling and packaging machine, a horizontal pillow filling and packaging machine, a multi-row filling and packaging machine, or the like. In this vertical filling and packaging machine, a long length of packaging laminate film 1 is continuously unwound from an original roll 11 and, while running in the longitudinal direction, is folded back in the width direction at a film folding back section 12 so that the sealant layers 4 face each other, and the overlapping side edges are continuously heat-sealed in the longitudinal direction by a pair of vertical sealing rolls of a vertical sealing means 13 to create a vertical seal section 14. The thus-formed cylindrical packaging laminate film 1 is continuously filled with packaged items M from a filling nozzle of a supply section 15, and a horizontal seal section 17 is formed across the entire width of the cylindrical packaging laminate film 1 while squeezing out the packaged items M with a pair of horizontal seal rolls of a horizontal sealing means 16. The horizontal seal section 17 is then cooled by a pair of horizontal seal rolls of a cooling section 18 to fix the bond, thereby producing a large number of packaging bags P and automatically filling each packaging bag P with the packaged items M.

[0016] Each layer constituting the packaging laminate film 1 will now be described. The base layer 2 is not particularly limited, but may be composed of, for example, a polyester film such as a polyethylene terephthalate film (PET) or polyethylene naphthalate, a polyolefin film such as a biaxially oriented polyethylene film or a biaxially oriented polypropylene film, a biaxially oriented nylon film, a polyvinyl alcohol film, an ethylene-vinyl alcohol copolymer film, paper, or the like. The base layer 2 may be vapor-deposited or coated with an oxide, nitride, or chloride of silicon, aluminum, titanium, or the like. The thickness of the base layer 2 is appropriately selected depending on the application, etc., but is preferably in the range of 9 to 80 μm in order to increase the strength, stiffness, barrier properties against gases, and pinhole resistance of the packaging laminate film 1.

[0017] The intermediate layer 3 is not particularly limited, and may be made of the same film material as the base layer 2. The intermediate layer 3 is provided to impart gas barrier properties, pinhole resistance, stiffness, light-shielding properties, etc. to the packaging laminate film 1, and may be appropriately selected according to the required properties, and may be provided in multiple layers. For example, when aluminum foil is formed as the intermediate layer 3, it is possible to impart gas barrier properties and light-shielding properties to the packaging laminate film 1.

[0018] 1 shows a two-layer structure of the first sealant layer 4a and the second sealant layer 4b, but the number of layers is not particularly limited and the sealant layer 4 is composed of at least two layers. The first sealant layer 4a located on the intermediate layer 3 side serves to bond the second sealant layer 4b and the intermediate layer 3 well, and the second sealant layer 4b serves to fuse and bond the layers by heating and pressurizing using heat sealing means (e.g., vertical sealing means 13 and horizontal sealing means 16 in FIG. 2) to form a heat-sealed portion (e.g., vertical sealing portion 14 and horizontal sealing portion 17 in FIG. 2).

[0019] Sealant layer 4 is made of, for example, low-density polyethylene, medium-density polyethylene, high-density polyethylene, linear low-density polyethylene, polypropylene, polypropylene-ethylene copolymer, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, ionomer resin, or the like. In particular, when the contents are filled and packaged by a submerged sealing method (a method in which the contents are squeezed out by a horizontal sealing means while the squeezed-out position is heat-sealed to form a horizontal seal portion) as in the vertical filling and packaging machine of FIG. 2, low-density polyethylene, medium-density polyethylene, high-density polyethylene, or linear low-density polyethylene is preferably used.

[0020] The first sealant layer 4a is mainly composed of, for example, low-density polyethylene, and contains an inorganic filler 5. The inorganic filler 5 is made of a material having excellent thermal conductivity or thermal diffusivity, and may be, for example, calcium carbonate, silica, zeolite, titanium oxide, alumina, zinc oxide, magnesium oxide, boron nitride, alumina nitride, etc., which may be used alone or in combination of two or more kinds. In particular, when the packaged item is food or drink, it is preferable to select the inorganic filler 5 in consideration of laws and regulations such as the Food Sanitation Act. The size of the inorganic filler 5 is not particularly limited, but an inorganic filler of about 1 μm to 20 μm is preferable because it is easy to control and disperse as a powder and has a stable surface.

[0021] By incorporating inorganic filler 5 in the first sealant layer 4a, the thermal conductivity or thermal diffusivity of the first sealant layer 4a is improved, and heat from a heat sealing means (e.g., vertical sealing means 13 and horizontal sealing means 16 in FIG. 2) can be efficiently supplied to the second sealant layer 4b. This broadens the lower limit of the sealable temperature range in the filling and packaging machine, making it possible to form a seal portion (e.g., vertical sealing portion 14 and horizontal sealing portion 17 in FIG. 2) with sufficient seal strength even at a low heat sealing temperature. Moreover, heat from the heat sealing means can be supplied to the second sealant layer 4b in a short time, enabling high-speed filling and improving productivity.

[0022] Furthermore, by using a natural material such as calcium carbonate for the inorganic filler 5, the amount of plastic resin in the packaging laminate film 1 can be reduced, which is expected to have an environmental impact.

[0023] When the sealant layer 4 is composed of three or more layers, the inorganic filler 5 may be added to any layer of the sealant layer 4 other than the outermost sealant layer, or may be added to multiple layers, and the same action and effect can be expected in any case.

[0024] The content of the inorganic filler 5 is in the range of 4 to 40% by weight, and preferably in the range of 16 to 32% by weight, of the entire sealant layer 4. If the content is less than 4% by weight, the inorganic filler 5 will not improve the thermal conductivity or thermal diffusivity of the sealant layer 4, and the temperature at which the seal can be made by the heat sealing means cannot be lowered. On the other hand, if the content exceeds 40% by weight, the amount of resin in the sealant layer 4 will decrease, resulting in problems such as a decrease in the seal strength. EXAMPLES

[0025] <Example 1> Packaging bags were produced using the comparative example and Examples 1 to 6 of the packaging laminate films shown in Table 1 with a vertical fill-seal machine (DANGAN (registered trademark) G2 standard machine, manufactured by Taisei Lamic Co., Ltd.) shown in FIG. 2. Note that, in the packaging laminate films of Examples 1 to 6, the sealant layer 4 has a three-layer structure (first sealant layer 4a, second sealant layer 4b, and third sealant layer 4c) as shown in FIG. 3. The second sealant layer 4b contains calcium carbonate (CaCO 3 A master batch containing 80% calcium carbonate (CaCO 3 ) was added in an amount of 5% by weight to 50% by weight.

[0026] The vertical seal temperature (vertical seal means 13 in FIG. 2) of the vertical fill-seal machine was set to 195°C, and the horizontal seal temperature (horizontal seal means 16 in FIG. 2) was changed in the range of 115-195°C, and a pressure resistance test was conducted on each of the produced packaging bags (a pressure force was applied from above while the packaging bag was laid horizontally, and the pressure until the bag broke was measured). The results are shown in Table 2. The bag production conditions were as follows. The first sealant layer 4a, the second sealant layer 4b, and the third sealant layer 4c were laminated by extrusion lamination. Bag dimensions: length 48mm x width 63mm Filling speed: 15m / min Vertical seal temperature: 195℃ Vertical seal pressure (MPa): 110 / 70 Horizontal seal pressure (MPa): 300 / 250 Contents: 15g water Liquid temperature: 30℃

[0027] [Table 1]

[0028] [Table 2]

[0029] From the results in Table 2, it was confirmed that in all of Examples 1 to 6, the addition of inorganic filler 5 to the second sealant layer 4b improved the thermal conductivity or thermal diffusivity of the second sealant layer 4b, and compared with the comparative example in which inorganic filler 5 was not added, the lower limit of the transverse sealable temperature range was expanded, making it possible to fill and package at higher speeds than before. 3 In the case of Examples 1 to 5 (CaCO 3When the cross-sealing temperature was lowered to 140°C, the packing material had a high pressure resistance of 540 kgf or more, and it was confirmed that the packing material can be suitably used even when packaging liquids or other items that require high pressure resistance.

[0030] <Example 2> For the packaging laminate films of the comparative example and examples 1 to 6 shown in Table 1, heat seal parts were formed using a pair of heat seal bars under conditions of temperature: 65 to 140°C and pressure: 0.2 MPa x 1 second, and the seal strength of each heat seal part was measured. The seal strength was measured by opening the test piece 180° with the heat-sealed part in the center, attaching both ends of the test piece to the grips of a tensile tester (grip interval 50 mm), applying a tensile load until the heat-sealed part broke, and determining the maximum load (N / 15 mm) during that time. The results are shown in Figure 4. Five measurements were taken for each test piece, and the average value was used.

[0031] From the results of FIG. 4, Examples 1 to 3 (CaCO 3 In the case where the content of the inorganic filler was 4 to 16% by weight, the heat seal strength was equivalent to that of the comparative example at all heat seal temperatures, and no effect of adding the inorganic filler was confirmed. When the heat sealing temperature exceeded 100°C, the seal strength tended to decrease as the amount of inorganic filler added increased; however, at a heat sealing temperature of 95°C or higher, all of the packaging laminate films of Examples 1 to 6 exhibited a high heat seal strength of 40 N / 15 mm or more, and it was confirmed that they can be suitably used as packaging bags. [Industrial Applicability]

[0032] The laminated film for packaging according to the present invention can be used in vertical fill packaging machines, vertical pillow fill packaging machines, horizontal pillow fill packaging machines, multi-row fill packaging machines, and the like. [Explanation of symbols]

[0033] 1. Laminated film for packaging 2 Base material layer 3. Middle tier 4 Sealant Layer 4a First sealant layer 4b Second sealant layer 4c Third sealant layer 5. Inorganic filler 11 Raw material roll 12 Film folding section 13 Vertical sealing means 14 Vertical seal part 15 Supply section 16 Horizontal sealing means 17 Horizontal seal section 18 Cooling section M Packaged item P packaging bag

Claims

1. A packaging laminate film for use in a filling and packaging machine equipped with a heat sealing means, The adhesive sheet includes at least a base layer and a sealant layer. The sealant layer has at least a two-layer structure, The packaging laminate film is characterized in that at least one of the sealant layers other than the outermost sealant layer contains an inorganic filler.

2. 2. The packaging laminate film according to claim 1, wherein the inorganic filler is at least one compound selected from the group consisting of calcium carbonate, silica, talc, zeolite, titanium oxide, alumina, zinc oxide, magnesium oxide, boron nitride and aluminum nitride.

3. 3. The packaging laminate film according to claim 1, wherein the content of the inorganic filler is 4% by weight to 40% by weight of the entire sealant layer.

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