Resin Stretch Film and Filled Package Using the Same

Abstract

To provide a resin stretched film and a filling package using the same which: firstly, allows a winding deviation of the film during a manufacturing process to be suppressed even if the film has an indentation; secondly, is hard to cause film breakage in the manufacturing process of the filling package; and thirdly, allows the filling package to be easily opened from an external ear part after being subjected to pressurizing / heating sterilization (heat-treatment).SOLUTION: There is provided a resin stretched film having an indentation which does not penetrate the resin stretched film, in which the resin stretched film has an indentation row where the indentations are aligned in the longitudinal direction of the resin stretched film at a side edge position of 0.50-15 mm from the side end of the resin stretched film. The distance between the indentations in the longitudinal direction is 2.0-3.9 mm, and the width of the indentation in the transverse direction of the resin stretched film is 0.65-3.5 mm.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a resin stretched film and a filled package using the same.

Background Art

[0002] A filled package filled with contents such as solid or paste-like processed foods such as sausage, cheese, hamburger, and mochi is usually formed by longitudinally sealing both side edges extending in the longitudinal direction of a strip-shaped resin film. The contents such as the processed foods are filled inside a cylindrical resin film having a longitudinally extending longitudinal seal portion, and both longitudinal ends of the cylindrical resin film are gathered and sealed by a metal wire clip such as an aluminum wire clip or a transverse seal film (reinforcing tape) or other means. As the resin for forming the cylindrical resin film provided in the filled package, polyolefin resins (such as polyethylene and polypropylene), polyamide resins (such as nylon-6), polyester resins (such as polyethylene terephthalate), polyvinyl chloride resins, polyvinylidene chloride resins, etc. are used. Among them, polyvinylidene chloride resins are preferably used because they have excellent oxygen gas barrier properties and a good balance of heat resistance and strength.

[0003] In order to remove the cylindrical resin film from these filled packages and take out the processed foods and other contents, it is necessary to cut and remove the gathered portions at both longitudinal ends of the cylindrical resin film, or cut the cylindrical resin film along the longitudinally sealed portions of both side edges extending in the longitudinal direction, or in a direction perpendicular to the longitudinally sealed portions to expose the contents. However, a cylindrical resin film, for example, a cylindrical resin film formed from a polyvinylidene chloride resin, is tough, so when consumers take out the contents, they may not be able to open it with only the strength of their fingers. In this case, there are problems such as having to prepare a cutting tool such as scissors or a knife for cutting, or even when using a cutting tool, the contents may not be well exposed.

[0004] An object of the present invention is to provide a filled package having an easy-opening property that allows for easy removal of the contents from the filled package. For example, Patent Document 1 discloses a sealed package including a tubular film formed by overlapping both side edges of a heat-shrinkable film such that the front and back surfaces of the heat-shrinkable film face each other and sealing them in the longitudinal direction, and a sealing member for sealing both ends of the tubular film filled with the contents. The side edge portion of the heat-shrinkable film having a scar row forms an outer ear piece protruding in a band shape outside the tubular film, and the longitudinal interval of the scars of the side edge portion after heat treatment is 3.0 mm to 28 mm.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, in the method described in Patent Document 1, since scars penetrating the film are imparted, film scraps are generated during manufacturing, and there is a risk of film scraps being mixed into the filled package. During the manufacture of the filled package, there is a risk of cracks occurring from the scar portion due to the tension applied to the film, resulting in film breakage. Also, it is difficult to say that the longitudinal interval of the scars is long enough to sufficiently achieve easy-opening property.

[0007] As one means for solving this problem, it is conceivable to provide indentations at short intervals in the longitudinal direction on the outer ear portions of the filled package. The filled package having indentations on such outer ear portions is manufactured using a film web having indentations on its side edges. Specifically, a film is unwound from a roll-shaped film web, the both side edges are overlapped and longitudinally sealed to form a tubular shape, and then cut to an appropriate length as needed. However, simply providing indentations causes the side edge portion having the indentations to stand out (the end portion becomes thicker compared to the central portion in the axial direction of the roll) in the roll of the film web, resulting in film slippage (when the film is wound into a roll, the end face of the roll becomes uneven), making it difficult to feed the film flat and impossible to form the film into a tubular shape. Also, simply providing indentations on the outer ear portions of the filled package makes it easier to open, but it is not always sufficient.

[0008] The present invention has been made in view of the above problems, and first, even if it has indentations, it is possible to suppress film slippage in the manufacturing process. Second, in the manufacturing process of the filled package, it is difficult to cause film breakage. Third, an object of the present invention is to provide a resin stretched film that can provide a filled package that can be easily opened from the outer ear portion after pressure heating sterilization (heat treatment), and a filled package using the same.

Means for Solving the Problems

[0009] The inventors of the present invention have found that a resin stretched film having indentations, wherein the indentations do not penetrate the resin stretched film, and the resin stretched film has a series of indentations arranged at a predetermined interval and a predetermined width at a predetermined position, can solve the above problems, and have completed the present invention.

[0010] The stretched resin film according to the present invention has indentations, the indentations do not penetrate the stretched resin film, and the stretched resin film has a row of indentations arranged in the longitudinal direction of the stretched resin film at a side edge portion from 0.50 mm to 15 mm from the side end of the stretched resin film. The longitudinal interval between the indentations is 2.0 mm to 3.9 mm, and the width of the indentations in the transverse direction of the stretched resin film is 0.65 mm to 3.5 mm.

[0011] In the above-mentioned stretched resin film, the number of rows of indentations is preferably 1 to 20 rows.

[0012] The above-mentioned stretched resin film preferably contains a vinylidene chloride resin.

[0013] The filled package according to the present invention is a filled package in which the contents are filled into a tubular stretched resin film formed by overlapping both side edges of the stretched resin film according to the present invention so that the front and back surfaces of the stretched resin film face each other and longitudinally sealed, and both ends are sealed. The side edge portion having the row of indentations of the stretched resin film forms an outer ear portion protruding in a strip shape to the outside of the tubular stretched resin film.

[0014] The above-mentioned filled package is preferably heat-treated.

[0015] The above-mentioned filled package preferably has through holes instead of at least a part of the indentations.

[0016] In the above-mentioned filled package, the outer ear portion preferably has a row of through holes arranged in the longitudinal direction of the outer ear portion at a side edge portion from 0.20 mm to 8.0 mm from the side end of the outer ear portion. The longitudinal interval between the through holes is 1.0 mm to 2.9 mm, and the width of the through holes in the transverse direction of the outer ear portion is 0.30 mm to 2.7 mm.

Effect of the Invention

[0017] According to the present invention, the above problems can be solved. That is, the resin stretched film according to the present invention can suppress film slippage during its manufacturing process even if it has indentations, and is also less likely to cause film breakage during the manufacturing process of the filled package. Further, the resin stretched film according to the present invention provides a filled package that can be easily opened from the outer ear part after pressure heating sterilization (heat treatment).

Brief Description of the Drawings

[0018]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Embodiments for Carrying Out the Invention

[0019] Hereinafter, embodiments of the present invention (hereinafter referred to as "the present embodiment") will be described in detail. However, the present invention is not limited thereto, and various modifications are possible without departing from the gist thereof.

[0020] 〔Cylindrical Resin Stretched Film〕 The filled package of the present invention is a filled package comprising a tubular resin stretched film and contents, wherein the tubular resin stretched film comprises a longitudinal seal portion having outer ear portions extending in the longitudinal direction, and both longitudinal ends are converged.

[0021] The resin stretched film according to the present invention is a resin stretched film having indentations (traces formed when pressed or pressure is applied), the indentations do not penetrate the resin stretched film, and the resin stretched film has a series of indentations arranged in the longitudinal direction of the resin stretched film at a side edge portion of 0.50 mm to 15 mm from the side end of the resin stretched film, the longitudinal interval of the indentations is 2.0 mm to 3.9 mm, and the width of the indentations in the transverse direction of the resin stretched film is 0.65 mm to 3.5 mm.

[0022] As the resin stretched film for forming the tubular resin stretched film, conventionally, a resin stretched film used for forming a tubular resin stretched film provided in a filled package in which contents such as processed foods such as sausage, process cheese, ham, hamburger, etc. are filled, enclosed, and individually packaged in a sealed state can be used.

[0023] 〔Heat shrinkage rate〕 The resin stretched film of the present invention preferably has heat shrinkability. The heat shrinkage rate at 100 °C in the MD (longitudinal direction of the film) is preferably 19% to 35%, more preferably 19% to 25%. Also, the heat shrinkage rate at 100 °C in the TD (transverse direction of the film) is preferably 19% to 30%, more preferably 19% to 25%. By making the heat shrinkage rates of MD and TD at 100 °C 19% or more, through holes are likely to be formed after heat treatment of the filled package. Also, by making the heat shrinkage rate at 100 °C 35% or less for MD and 30% or less for TD, bending and shrinkage of the filled package can be suppressed after heat treatment of the filled package.

[0024] 〔Indentation〕 Regarding the indentation of the resin stretched film of this embodiment, it will be described with reference to FIG. 1, which is a perspective view of the resin stretched film, and FIGS. 2 to 8 showing the mode of indentation. As shown in FIG. 1, the resin stretched film 1 of this embodiment has an indentation 4 in at least a part of a side edge portion 3 which is a region from 0.50 mm to 15 mm from a side end 2. Here, it is not necessary for all side edge portions to have the indentation 4. As a preferred mode, it is sufficient if one side edge portion among the side ends along the MD (longitudinal direction of the film) has an indentation.

[0025] As shown in FIG. 2, the depth a of the indentation 4 that does not penetrate the resin stretched film 1 is preferably 10% to 90%, more preferably 20% to 60% with respect to the total film thickness before indentation application (in the case of two-layer lamination, the thickness of the two laminated layers). By setting the depth a of the indentation 4 to be 10% or more with respect to the total film thickness before indentation application, opening becomes easy, and by setting it to 90% or less, film breakage during the manufacturing process is suppressed. Also, the shape of the indentation 4 is not particularly limited, and as shown in FIGS. 3 to 6, examples include a quadrangle, an ellipse, a polygonal line shape, a triangle, etc.

[0026] The indentations 4 are arranged in the longitudinal direction (MD in FIG. 1) to form an indentation row 5. The number of indentation rows is preferably 1 to 20 rows, more preferably 1 to 3 rows, and even more preferably 2 rows. Also, as shown in FIGS. 7 and 8, when there are a plurality of indentation rows 5, the positions of the indentations 4 in adjacent indentation rows 5 may be at the same position or shifted in the longitudinal direction, and the intervals between the indentations 4 in the indentation rows 5 may be the same or different between rows. Furthermore, regarding the intervals between the indentations 4 within the same row, as long as they satisfy a predetermined range (2.0 mm to 3.9 mm), they may be equal or unequal.

[0027] As shown in FIGS. 7 and 8, the interval b between the indentations 4 in the indentation row 5 is 2.0 mm to 3.9 mm, preferably 2.5 mm to 3.5 mm, and more preferably 2.5 mm to 3.0 mm. When the interval between the indentations 4 is 3.9 mm or less, the number of unsealed portions increases and the easy-openability is improved. Further, when the interval between the indentations is 2.0 mm or more, the standing-up is alleviated and the film slippage during the manufacturing process is suppressed.

[0028] As shown in FIGS. 7 and 8, the width c of the indentation 4 in the indentation row 5 is 0.65 mm to 3.5 mm, preferably 0.80 mm to 1.2 mm, and more preferably 0.80 mm to 1.0 mm. When the width of the indentation 4 is 0.65 mm or more, the indentation can be stably imparted without penetrating the film during the manufacturing process. Further, when the width of the indentation 4 is 3.5 mm or less, the standing-up is alleviated and the film slippage during the manufacturing process is suppressed. Further, when there are a plurality of indentation rows, the interval d between those indentation rows is preferably 0.01 mm to 8.2 mm, more preferably 0.80 mm to 1.2 mm, and even more preferably 0.80 mm to 1.0 mm.

[0029] As shown in FIGS. 7 and 8, the interval e from the side end 2 to the indentation 4 in the indentation row 5 is preferably 0.50 mm to 2.0 mm, more preferably 0.80 mm to 1.5 mm, and even more preferably 1.0 mm to 1.5 mm. When the interval e from the side end 2 to the indentation 4 is 0.50 mm or more, the film breakage during the manufacturing process is suppressed. Further, when the interval e from the side end 2 to the indentation 4 is 2.0 mm or less, the easy-openability is improved.

[0030] 〔Resin material〕 Examples of the resin material for forming the tubular resin stretched film include polyvinylidene chloride-based resins, polyvinyl chloride-based resins, polyester-based resins (such as polyethylene terephthalate), polyamide-based resins (such as nylon-6), and polyolefin-based resins (such as polyethylene and polypropylene). From the viewpoints of oxygen gas barrier properties and water vapor barrier properties, the tubular resin stretched film is preferably formed from a polyvinylidene chloride-based resin.

[0031] [Polyvinylidene chloride resin] The polyvinylidene chloride resin (hereinafter sometimes referred to as "PVDC"), which is preferably used as a resin material for forming a tubular resin stretched film, may be a homopolymer of vinylidene chloride, but is usually a copolymer of 60 to 98% by mass of vinylidene chloride and 2 to 40% by mass of other monomers copolymerizable with vinylidene chloride. Examples of other monomers copolymerizable with vinylidene chloride include vinyl chloride; alkyl acrylate esters such as methyl acrylate, ethyl acrylate, butyl acrylate, and lauryl acrylate (the alkyl group having 1 to 18 carbon atoms); alkyl methacrylate esters such as methyl methacrylate, butyl methacrylate, and lauryl methacrylate (the alkyl group having 1 to 18 carbon atoms); vinyl cyanides such as acrylonitrile; aromatic vinyls such as styrene; vinyl esters of aliphatic carboxylic acids having 1 to 18 carbon atoms such as vinyl acetate; alkyl vinyl ethers having 1 to 18 carbon atoms; vinyl polymerizable unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, and fumaric acid; alkyl esters of vinyl polymerizable unsaturated carboxylic acids such as maleic acid, fumaric acid, and itaconic acid (including partial esters, the alkyl group having 1 to 18 carbon atoms), and the like. More preferably, it is at least one selected from vinyl chloride, methyl acrylate, or lauryl acrylate. Other monomers copolymerizable with vinylidene chloride may be used alone or in combination of two or more. The copolymerization ratio of other monomers is more preferably in the range of 3 to 35% by mass, still more preferably 3 to 25% by mass, and particularly preferably 4 to 22% by mass. If the copolymerization ratio of other monomers is too small, the melt processability tends to decrease, while if the copolymerization ratio of other monomers is too large, the oxygen gas barrier property tends to decrease. Also, two or more kinds of PVDC may be mixed to improve the melt processability.

[0032] The PVDC preferably used in the present invention can be synthesized by any polymerization method such as suspension polymerization method, emulsion polymerization method, solution polymerization method, etc. However, when forming a compound as a powder resin, it is preferably synthesized by the suspension polymerization method. When synthesized by the suspension polymerization method in this way, there is a tendency that a pulverization step for adjusting the particle size of the powder resin made of PVDC is not required. The particle size of such a powder resin made of PVDC is preferably in the range of 40 μm to 2 mm, more preferably in the range of 50 μm to 1 mm, and even more preferably in the range of 60 to 700 μm. The particle size of the powder resin is measured, for example, by a dry sieving method using a standard sieve.

[0033] 〔Additive〕 The resin material for forming a cylindrical resin stretched film, preferably PVDC, can contain various additives such as heat stabilizers, plasticizers, processing aids, colorants, ultraviolet absorbers, pH adjusters, dispersion aids, etc., which are added as needed for the purpose of improving various properties and moldability.

[0034] For example, as heat stabilizers, epoxy compounds such as epoxidized vegetable oils, epoxidized animal oils, epoxidized fatty acid esters, and epoxy resin prepolymers; epoxy group-containing resins, etc. may be mentioned, and epoxidized vegetable oils are preferably used. When using a heat stabilizer, the content is preferably in the range of 0.05 to 6 parts by mass, more preferably in the range of 0.08 to 5 parts by mass, and particularly preferably in the range of 0.1 to 4 parts by mass with respect to 100 parts by mass of the resin material, preferably PVDC. When the content of the heat stabilizer is 0.05 parts by mass or more, it is easy to sufficiently improve the heat stability, the molding process becomes easy, and blackening is less likely to occur. On the other hand, when the content of the heat stabilizer is 6 parts by mass or less, the oxygen gas barrier property and cold resistance of the tubular resin stretched film are less likely to deteriorate, and bleeding and fish eyes are less likely to occur. Regarding the types and addition amounts of other additives, they can be selected in the same manner as in the various additives used in the conventional tubular resin stretched film provided in the filled package. These additives may be used alone or in combination of two or more. Further, a part or all of the amount of these additives may be contained in the monomer composition in the polymerization step of the resin material such as PVDC, or may be blended with the resin material such as PVDC after polymerization.

[0035] 〔Other resins〕 Furthermore, for the resin material for forming a tubular resin stretched film, preferably PVDC, for the purpose of improving various properties and moldability, other resins such as polyethylene wax, oxidized polyethylene wax, polyethylene (low-density polyethylene or high-density polyethylene), ethylene-vinyl acetate copolymer, homopolymer or copolymer of acrylic acid ester, homopolymer or copolymer of methacrylic acid ester, and methyl methacrylate-butadiene-styrene copolymer can be contained as necessary. The acrylic acid ester or methacrylic acid ester is preferably an alkyl ester having 1 to 18 carbon atoms in the alkyl group. When using other resins, the content is preferably 20 parts by mass or less, more preferably 16 parts by mass or less, still more preferably 10 parts by mass or less, and particularly preferably 5 parts by mass or less with respect to 100 parts by mass of the resin material, preferably PVDC.

[0036] The properties, shape, and size of other resins can be appropriately selected as desired in consideration of the uniform dispersibility with the resin material for forming the tubular resin stretched film. For example, it may be in a solid state such as granular, powdery, or pellet-like, or in a liquid or molten state. Also, if desired, the surface of other resins may be surface-treated.

[0037] 〔Size and Thickness of Tubular Resin Stretched Film〕 The size and thickness of the tubular resin stretched film are determined according to the size of the content to be filled. The circumference of the tubular resin stretched film is, for example, in the range of 15 to 400 mm, often 30 to 300 mm, and widely adopted in the range of 40 to 200 mm. The length in the longitudinal direction of the tubular resin stretched film is, for example, in the range of 50 to 400 mm, often 70 to 300 mm, and widely adopted in the range of 80 to 250 mm. Also, the thickness of the tubular resin stretched film is determined in consideration of the strength of the film and oxygen gas barrier properties according to the content to be filled. For example, it is in the range of 15 to 300 μm, often 18 to 200 μm, and widely adopted in the range of 20 to 150 μm.

[0038] In order to increase the strength, improve the oxygen gas barrier property, improve the heat resistance, adjust the shrinkage property, etc. of the tubular resin stretched film, a laminated film can be used. For example, a laminated film of a PVDC film and another resin stretched film such as a polyethylene terephthalate film or a polypropylene film can be used. Further, the tubular resin stretched film may be printed.

[0039] Note that as the tubular resin stretched film, there are a non-adhesive film that does not adhere to the contents filled in the tubular resin stretched film and an adhesive film that adheres to the contents filled therein, and any of them can be used in the tubular resin stretched film provided in the filled package of the present invention. Since there is no air inside by adhering to the contents to be filled, from the viewpoint of preventing spoilage, a tubular resin stretched film that is an adhesive film is often preferable. However, if the adhesive force between the tubular resin stretched film and the contents is too large, the resin stretched film may be difficult to peel off from the contents such as processed foods, and it may be difficult to take out the contents.

[0040] 〔Manufacture of Tubular Resin Stretched Film〕 The tubular resin stretched film in the present invention can be obtained by a method conventionally employed as a method for manufacturing a tubular resin stretched film provided in a filled package. Specifically, a tubular film is formed by winding a strip-shaped resin stretched film in a tubular shape so that both side edges extending in the longitudinal direction overlap, and then the two side edges of the tubular film are longitudinally sealed to form a tubular resin stretched film.

[0041] 〔Manufacture of Strip-shaped Resin Stretched Film〕 The method for manufacturing the belt-shaped resin stretched film for forming the cylindrical resin stretched film is not particularly limited. For example, by extrusion molding, a sheet-shaped or tubular extruded film is formed and stretched to impart heat shrinkability. In the case of a tubular extruded film, the inner sides can be overlapped to obtain a two-ply belt-shaped resin stretched film having a predetermined width, and if necessary, by cutting in the longitudinal direction, a belt-shaped resin stretched film having a desired width can be manufactured. When the cylindrical resin stretched film is a laminated film, a belt-shaped resin stretched film laminated by coextrusion molding or extrusion lamination may be manufactured, or a belt-shaped resin stretched film laminated by adhering a plurality of films with an adhesive, for example, a urethane-based adhesive, may be manufactured. When the cylindrical resin stretched film is to be printed, the obtained belt-shaped resin stretched film may be printed.

[0042] 〔Manufacture of indentations〕 The method for manufacturing the indentations imparted to the resin stretched film in the present invention is not particularly limited. For example, as shown in FIG. 9, by sandwiching a specific position of the resin stretched film 1 between a disk rotary pressing body 6 and a roll member 7 and pressing the resin stretched film, indentations can be imparted to the film.

[0043] 〔Longitudinal seal part having outer ear parts extending in the longitudinal direction〕 The cylindrical resin stretched film of the present invention is provided with a longitudinal seal part having outer ear parts extending in the longitudinal direction. That is, the cylindrical resin stretched film in the present invention is provided with a longitudinal seal part extending in the longitudinal direction, and the longitudinal seal part has outer ear parts extending in the same longitudinal direction.

[0044] 〔Longitudinal seal part extending in the longitudinal direction〕 The longitudinally extending longitudinal seal portion provided in the tubular resin stretched film is provided in the same manner as the longitudinally extending longitudinal seal portion provided in the tubular resin stretched film provided in the filled package. That is, a belt-shaped resin stretched film is wound into a tubular shape so that both side edges extending in the longitudinal direction overlap to form a tubular film. Then, the both side edges of the tubular film are continuously sealed (adhered) in the longitudinal direction (vertical direction) according to conventional methods such as welding by high-frequency dielectric heating, ultrasonic heating, laser heating, resistance heating, etc., adhesion with an adhesive (including heat sealing). By doing so, a tubular resin stretched film is formed. The longitudinal seal portion is provided over the entire longitudinal length of the tubular resin stretched film, whereby the contents filled and enclosed in the tubular resin stretched film can be stored in a sealed state. The width of the longitudinally extending longitudinal seal portion provided in the tubular resin stretched film can be appropriately determined.

[0045] 〔Longitudinally extending outer ear portion〕 The longitudinally extending outer ear portion, which is also longitudinally extending and is provided in the longitudinally extending longitudinal seal portion of the tubular resin stretched film in the present invention, refers to the side end portions orthogonal to the longitudinal direction of the side edges exposed on the outer surface when the both side edges of the above-mentioned belt-shaped resin stretched film of the tubular film are continuously sealed (adhered) in the longitudinal direction (vertical direction) according to a conventional method. It is a non-sealed portion extending in the longitudinal direction of the formed tubular resin stretched film. The width of the outer ear portion is, for example, in the range of 1 to 15 mm, and in many cases, 2 to 8 mm. The longitudinally extending outer ear portion (non-sealed portion) is formed, for example, with a uniform width over the entire longitudinal length of the tubular resin stretched film, but it may be formed so that the widths of the outer ear portions (non-sealed portions) are different.

[0046] 〔Convergence of both longitudinal ends〕 The filled package of the present invention includes a longitudinal seal portion having outer ear portions extending in the longitudinal direction, and a tubular resin stretched film with both longitudinal ends converged. That is, the filled package of the present invention is formed by filling a tubular resin stretched film with contents such as processed foods and then converging both longitudinal ends of the tubular resin stretched film, and the contents can be stored in a sealed state. The convergence of both longitudinal ends of the tubular resin stretched film can adopt the conventional convergence method for both longitudinal ends of the tubular resin stretched film provided in the filled package, for example, a metal wire clip such as an aluminum wire clip or a lateral seal film (reinforcing tape) or other means of convergence method.

[0047] 〔Filled Package〕 The filled package of the present invention is a filled package in which both side edges of a resin stretched film are overlapped so that the front and back surfaces of the resin stretched film face each other and longitudinally sealed to form a tubular resin stretched film, and both ends of the tubular resin stretched film filled with contents are sealed. The side edge portion having the indentation row of the resin stretched film forms an outer ear portion protruding in a strip shape outside the tubular resin stretched film. By subjecting the filled package to pressure heating sterilization (heat treatment), at least a part of the indentation can be turned into a through hole. It has an opening property even with the indentation remaining (not becoming a through hole), but the opening property is further improved by becoming a through hole. The reason why at least a part of the indentation becomes a through hole by subjecting the filled package to pressure heating sterilization (heat treatment) is not necessarily clear, but it is considered that a shrinkage force is generated in the resin stretched film during pressure heating sterilization (heat treatment), and stress concentration occurs at the thin part of the indentation thickness, thereby forming a through hole.

[0048] Fig. 10 shows a perspective view of the filled package 11. The cylindrical resin stretched film is formed by overlapping both side edges of the resin stretched film so that the side edge 3 having the indentation row 5 of the resin stretched film 1 protrudes in a strip shape to the outside of the cylindrical resin stretched film to form an outer ear part 8, and longitudinally sealing them so that the front and back surfaces of the resin stretched film face each other. The filled package 11 with the contents sealed is subjected to pressure heating sterilization (heat treatment). In the through hole row 10 in which the through holes 9 formed in the outer ear part 8 are arranged, the indentation 4 penetrates due to pressure heating sterilization (heat treatment). Starting from such a group of through holes, the outer ear part can be easily cut with fingers.

[0049] The interval b' between the through holes in the through hole row in the filled package after pressure heating sterilization (heat treatment) is 1.0 mm to 2.9 mm, preferably 1.6 mm to 2.8 mm. When the interval between the through holes is 1.0 mm or more, the through holes are prevented from being cut and connected, and unintended cutting from the through hole part can be suppressed. Also, when the interval between the through holes is 2.9 mm or less, the easy-openability is further improved.

[0050] The width c' of the through holes in the through hole row in the filled package after pressure heating sterilization (heat treatment) is 0.30 mm to 2.7 mm, preferably 0.35 mm to 0.6 mm. Also, when there are a plurality of through hole rows, the interval d' between those through hole rows is 0.01 mm to 7.6 mm, preferably 0.50 mm to 0.90 mm.

[0051] The interval e' between the through holes in the through hole row from the side end of the outer ear part in the filled package after pressure heating sterilization (heat treatment) is 0.20 mm to 1.5 mm, preferably 0.40 mm to 1.0 mm. When the interval between the through holes in the through hole row from the side end of the outer ear part is within the above range, the easy-openability is further improved and unintended cutting can be suppressed.

Example

[0052] Examples and comparative examples are shown below to further illustrate the present invention, but the present invention is not limited to these examples. The characteristics of the filled package of the present invention were measured by the following methods.

[0053] 〔Manufacturing suitability: Film misalignment during the manufacturing process〕 A roll was prepared by winding 1500 m of a film with an indentation provided on one side of the side edge of the resin stretched film. Those without film misalignment were evaluated as having no problem in manufacturing suitability (denoted as "〇" in the table). Those with film misalignment were evaluated as having a problem in manufacturing suitability (denoted as "×" in the table).

[0054] 〔Indentation state〕 1 m of the film was pulled out from the roll of the above film, and it was visually confirmed whether an indentation was provided on one side of the side edge of the film. If an indentation was provided on the side edge of the film, it was evaluated that there was no problem in the indentation state (denoted as "〇" in the table). If a through hole was provided on the side edge of the film, it was evaluated that there was a problem in the indentation state (denoted as "×" in the table).

[0055] 〔Thermal shrinkage rate〕 The thermal shrinkage rate of the resin stretched film was calculated from the following formula by immersing a 100 mm square resin stretched film in hot water at 100 °C for 3 minutes, then taking it out and cooling it to room temperature, and measuring the dimensions of the shrunk film sample. ·Thermal shrinkage rate of MD (%) (100 - length of MD of the film after shrinkage (mm)) / 100 × 100 ·Thermal shrinkage rate of TD (%) (100 - length of TD of the film after shrinkage (mm)) / 100 × 100

[0056] 〔Retort (pressure heating sterilization) resistance〕 The retort resistance of the filled package of the present invention was carried out and evaluated according to the following method. That is, using an RCS type retort sterilizer FlavorAce-60 / 10TG manufactured by Nisshapan Co., Ltd., 10 filled packages were subjected to a temperature of 120 °C and a pressure of 2.0 kg / cm 2After leaving it to stand in the retort pan at (gage pressure) for 10 minutes, it was taken out, and the number of packages with the longitudinal seal part peeled off or with cracks in the longitudinal seal part (number of punctures) was visually counted. If the number of punctures was 0, the filled package was evaluated as having retort resistance (indicated as "○" in the table). If the number of punctures was 1 or more, the filled package was evaluated as not having retort resistance (indicated as "×" in the table).

[0057] 〔Through-hole state〕 Among the filled packages after the above retort treatment, 5 packages without punctures were sampled. The number of samples with through-holes provided in the outer ear part of the obtained samples was visually counted. If a through-hole was provided in the outer ear part, it was evaluated that there was no problem with the through-hole state. (Indicated as "〇" in the table). If no through-hole was provided in the outer ear part and it was in an indentation state, it was evaluated that there was a problem with the through-hole state. (Indicated as "×" in the table).

[0058] 〔Easy-openability〕 Among the sealed packages after the above retort treatment, 1 package without punctures was randomly sampled. For the obtained sample, if the outer ear part could be pinched and opened, it was evaluated that the easy-openability was good. (Indicated as "〇" in the table). If the outer ear part could not be pinched and opened, it was evaluated that the easy-openability was poor. (Indicated as "×" in the table).

[0059] 〔Example 1〕 PVDC (a vinylidene chloride - vinyl chloride copolymer manufactured by Kuraray Co., Ltd. It was prepared such that the content of the structural unit derived from vinylidene chloride was 89% by mass and the content of the structural unit derived from vinyl chloride was 11% by mass.) was melted and extruded from an annular die to produce an annular film. At a stretching temperature of 28 °C, inflation biaxial stretching was performed 2.4 times in the MD (longitudinal direction) and 4.0 times in the TD (transverse direction). The inner sides of the annular film were overlapped to obtain a belt-shaped stretched PVDC film with a thickness of 40 μm (the thickness of two 20-μm-thick films). The heat shrinkage rates of the obtained belt-shaped stretched PVDC film were 22.4% in the MD and 19.9% in the TD. Subsequently, the belt-shaped film was cut to obtain a belt-shaped film stock with indentations applied as shown in Fig. 7. The depth a of the indentation was 25% (10 μm) of the total film thickness, the interval b between the indentations was 3.0 mm, the width c of the indentation was 0.8 mm, the interval d between the indentation rows was 1.0 mm, the interval e from the film side edge to the indentation was 1.5 mm, and there were two rows of indentations (the a, b, and c in the two rows were the same, and the longitudinal interval f between adjacent indentation rows was 1.5 mm). Subsequently, the belt-shaped PVDC film was wound into a cylindrical shape such that the two side edges extending in the longitudinal direction overlapped to form a cylindrical film. The overlapped two side edges of the cylindrical film were passed between the seal electrode and the ground electrode of a high-frequency dielectric heating device to which high-frequency power based on a predetermined voltage and current was applied, thereby longitudinally sealing the two side edges of the cylindrical film to form a cylindrical PVDC film having a longitudinal seal portion with outer ear portions 8 mm wide extending in the longitudinal direction. Subsequently, minced fish for fish sausage (52% fish mince, 23% water, 13% starch, 10% lard, 2% salt) was supplied from a filling device to the cylindrical PVDC film and filled. Then, both ends of the cylindrical PVDC film in the longitudinal direction were gathered and cut with an aluminum wire clip to produce a filled package with a circumference of 42 mm and a length between clips of 170 mm. Each of the filled packages was filled and sealed with 20 g of minced fish for fish sausage. Table 1 shows the evaluation results of various performance evaluations before retort, and Table 2 shows the evaluation results of various performance evaluations after retort (pressure heating sterilization).

[0060]

Table 1

[0061]

Table 2

[0062] As shown in Table 1 and Table 2, even if the resin stretched film according to the present invention has indentations, film slippage can be suppressed in the manufacturing process, and it was confirmed that film breakage is less likely to occur in the manufacturing process of the filled package. Similarly, it was confirmed that the resin stretched film according to the present invention provides a filled package that can be easily opened from the outer ear part after pressure heating sterilization (heat treatment).

Explanation of Signs

[0063] 1: Resin stretched film, 2: Side end, 3: Side edge part, 4: Indentation, 5: Indentation row, 6: Disk rotary pressing body, 7: Roll member, 8: Outer ear part, 9: Through hole, 10: Through hole row, 11: Filled package

Claims

1. A resin stretched film having indentations, wherein the indentations do not penetrate the resin stretched film, the resin stretched film has an indentation row in which the indentations are arranged in the longitudinal direction of the resin stretched film at a side edge portion of 0.50 mm to 15 mm from a side end of the resin stretched film, the interval in the longitudinal direction of the indentations is 2.0 mm to 3.9 mm, the width of the indentations in the transverse direction of the resin stretched film is 0.65 mm to 3.5 mm, A resin stretched film in which the interval between the indentations of the indentation row is 0.50 mm to 2.0 mm from the side end.

2. The resin stretched film according to claim 1, wherein the number of indentation rows is 1 to 20 rows.

3. The resin stretched film according to claim 1 or 2, containing a vinylidene chloride resin.

4. A filled package in which both side edge portions of the resin stretched film according to any one of claims 1 to 3 are overlapped so that the front and back surfaces of the resin stretched film face each other and are longitudinally sealed in the longitudinal direction, and the interior is filled and both ends are sealed. The filled package, wherein a side edge portion having an indentation row of the resin stretched film forms an outer ear portion protruding in a strip shape to the outside of the cylindrical resin stretched film.

5. The filled package according to claim 4, which has been heat-treated.

6. The filled package according to claim 5, having through holes instead of at least a part of the indentations.

7. The filled package according to claim 6, wherein the outer ear portion has a through hole row in which the through holes are arranged in the longitudinal direction of the outer ear portion at a side edge portion of 0.20 mm to 8.0 mm from a side end of the outer ear portion, the interval in the longitudinal direction of the through holes is 1.0 mm to 2.9 mm, and the width of the through holes in the transverse direction of the outer ear portion is 0.30 mm to 2.7 mm.

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