Vinylidene chloride resin composition, stretched film and filled packaging

Abstract

Provided is a vinylidene chloride-based resin composition by which a filling package that does not easily undergo incomplete opening can be obtained, even in a case in which two films disposed on a radially inward side are welded to two films disposed on a radially outward side. Also provided are a vinylidene chloride-based resin stretched film and a filling package that use the vinylidene chloride-based resin composition.　The vinylidene chloride-based resin composition according to the present disclosure contains a polyvinylidene chloride-based resin and a resin comprising an ethylene-vinyl acetate copolymer. The tensile elastic modulus of the resin comprising the ethylene-vinyl acetate copolymer at 23°C is 43-45 MPa, and the amount of the resin comprising the ethylene-vinyl acetate copolymer is 2-3 parts by mass per 100 parts by mass of the polyvinylidene chloride-based resin.

Description

[Technical Field]

[0001] The present disclosure relates to a vinylidene chloride resin composition, a stretched vinylidene chloride resin film using the same, and a filled package. [Background technology]

[0002] It is known that packages produced by filling a cylindrical film with contents such as sausages or stick cheese and tying both ends can be produced by a package manufacturing device that includes a mechanism for winding a strip of film into a cylindrical shape and overlapping and vertically sealing the side edges to form a cylindrical film, a mechanism for filling the cylindrical film with contents, and a mechanism for tying both ends of the cylindrical film filled with contents.In such a package manufacturing device, when winding the strip of film into a cylindrical shape and overlapping and sealing the side edges, a so-called envelope sealing is performed in which the front surface of one side edge of the cylindrically wound film is overlapped with the back surface of the other side edge (see, for example, Patent Document 1).

[0003] As the strip-shaped raw film, a seamless single-layer tube formed by extrusion of a polyvinylidene chloride resin may be used, but in many cases, a long film is used in which a tubular film formed by extrusion of a polyvinylidene chloride resin is folded to form a flat two-layer film, and the two-layer film is then slit to the desired width (see, for example, Patent Document 2).

[0004] When opening this filled packaging body consisting of two layers of film by pinching the outer edge with the fingers, only the surface layer of the film (the part located outermost in the radial direction) peels off, and one of the two films located on the radially outer side does not peel off from the vertical seal, resulting in incomplete opening. To solve this problem, a packaging body and a manufacturing method thereof have been proposed in which two films arranged radially outward and one of two films arranged radially inward is welded together and the other is located radially outward (see Patent Document 3). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2005-231639 A (paragraphs 0030, 0032, etc.) [Patent Document 2] JP 2005-48109 A (paragraph 0008) [Patent Document 3] Patent Publication No. 2021-1027 Summary of the Invention [Problem to be solved by the invention]

[0006] However, Patent Document 3 does not describe any specific manufacturing methods for use when using a long film with uneven thickness in the longitudinal direction. For example, if one of two films arranged radially inside has a thin portion in the longitudinal direction on the radially outer side, continuous manufacturing using such a film may change the radial temperature distribution, and the two films arranged radially inside may be welded together with the two films arranged radially outside.

[0007] The present disclosure has been made in consideration of the above-mentioned problems, and its purpose is to provide a vinylidene chloride resin composition that provides a filled package that is less likely to be incompletely opened even when two films arranged radially inside are welded together with two films arranged radially outside, a vinylidene chloride resin stretched film using the same, a filled package, and a method for manufacturing a filled package. [Means for solving the problem]

[0008] The present inventors have discovered that in a vinylidene chloride resin composition containing a polyvinylidene chloride resin and a resin made of an ethylene-vinyl acetate copolymer, by setting the tensile modulus of the resin made of ethylene-vinyl acetate copolymer to 43 MPa or more and 45 MPa or less and setting the amount of the resin made of ethylene-vinyl acetate copolymer to 2 parts by mass or more and 3 parts by mass or less, a filled package produced using a stretched film obtained from the vinylidene chloride resin composition is less likely to be incompletely opened even when two films arranged radially inside are welded together with two films arranged radially outside, and have completed the present disclosure.

[0009] The vinylidene chloride resin composition according to the present disclosure contains a polyvinylidene chloride resin and a resin made of an ethylene-vinyl acetate copolymer, wherein the resin made of the ethylene-vinyl acetate copolymer has a tensile modulus at 23°C of 43 MPa or more and 45 MPa or less, and the amount of the resin made of the ethylene-vinyl acetate copolymer in the vinylidene chloride resin composition is 2 parts by mass or more and 3 parts by mass or less per 100 parts by mass of the polyvinylidene chloride resin.

[0010] In the resin made of the ethylene-vinyl acetate copolymer, it is preferable that the concentration of structural units derived from vinyl acetate in the ethylene-vinyl acetate copolymer is 16% by mass or more and 19% by mass or less, and that the melt flow rate of the ethylene-vinyl acetate copolymer is 0.4 g / 10 min or more and less than 0.9 g / 10 min.

[0011] The stretched vinylidene chloride resin film according to the present disclosure is constructed by stacking two films each made of the vinylidene chloride resin composition and having a thickness of 10 μm or more and 300 μm or less.

[0012] The filled package according to the present disclosure is a cylindrical stretched vinylidene chloride resin film in which both side edge portions of the stretched vinylidene chloride resin film are overlapped so that the front and back surfaces of the stretched vinylidene chloride resin film face each other, and the film is longitudinally sealed, and contents are filled into the cylindrical stretched vinylidene chloride resin film and both ends are sealed, and the side edge portions of the stretched vinylidene chloride resin film form outer ear portions that protrude in a band-like shape outside the cylindrical stretched vinylidene chloride resin film.

[0013] The vertical seal portion is preferably formed by welding together two films arranged radially inside and two films arranged radially outside. [Effects of the Invention]

[0014] According to the present disclosure, it is possible to provide a vinylidene chloride resin composition that provides a filled package that is less likely to be incompletely opened when the outer edge of the filled package consisting of two overlapping two-layer films is pinched with the fingers to open it, even when the two films arranged radially inside are welded together with the two films arranged radially outside, and a vinylidene chloride resin stretched film, filled package, and method for manufacturing the filled package using the same. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a schematic diagram of a filled package according to the present disclosure. [Figure 2] This is a schematic cross-sectional view of the vicinity of the vertical seal portion of a filled packaging body according to the present disclosure, showing that at the vertical seal portion, two films arranged radially inside are welded together with two films arranged radially outside. [Figure 3] 1 is an explanatory diagram for explaining an example of a method for manufacturing a filled package according to the present disclosure. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0016] <Vinylidene chloride resin composition> The vinylidene chloride resin composition according to the present disclosure contains a polyvinylidene chloride resin and a resin made of an ethylene-vinyl acetate copolymer, and the resin made of the ethylene-vinyl acetate copolymer has a tensile modulus of elasticity at 23°C of 43 MPa or more and 45 Pa or less. By setting the tensile modulus of the resin made of ethylene-vinyl acetate copolymer within the above range, when the outer edge of a filled package made of two overlapping two-layer films is pinched with the fingers to open it, incomplete opening is less likely to occur even if the two films arranged radially inside are welded together with the two films arranged radially outside. Although the reason for the improved openability is not entirely clear, it is thought that the dispersion state, orientation, and stretch state of the resin made of ethylene-vinyl acetate copolymer dispersed in the polyvinylidene chloride resin change depending on the elastic modulus of the resin made of ethylene-vinyl acetate copolymer, resulting in improved openability. In this specification, the tensile modulus at 23° C. of a resin made of an ethylene-vinyl acetate copolymer is a value measured by the method described in the examples below.

[0017] [Polyvinylidene chloride resin] Polyvinylidene chloride resin (hereinafter sometimes referred to as "PVDC") may be a homopolymer of vinylidene chloride, or a copolymer of 60% by mass or more and 98% by mass or less of vinylidene chloride and 2% by mass or more and 40% by mass or less of another monomer copolymerizable with vinylidene chloride. Examples of other monomers copolymerizable with vinylidene chloride include vinyl chloride; alkyl acrylate esters (alkyl group having 1 to 18 carbon atoms) such as methyl acrylate, ethyl acrylate, butyl acrylate, and lauryl acrylate; alkyl methacrylate esters (alkyl group having 1 to 18 carbon atoms) such as methyl methacrylate, butyl methacrylate, and lauryl methacrylate; 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; and alkyl esters (including partial esters, alkyl group having 1 to 18 carbon atoms) of vinyl-polymerizable unsaturated carboxylic acids such as maleic acid, fumaric acid, and itaconic acid. At least one monomer selected from vinyl chloride, methyl acrylate, and lauryl acrylate is more preferred. The other monomers copolymerizable with vinylidene chloride may be used singly or in combination of two or more. The copolymerization ratio of the other monomer is more preferably 3% by mass or more and 35% by mass or less, and even more preferably 10% by mass or more and 30% by mass or less. When the copolymerization ratio of the other monomer is 3% by mass or more, melt processability is unlikely to deteriorate, while when the copolymerization ratio of the other monomer is 35% by mass or less, gas barrier properties are unlikely to deteriorate. Furthermore, two or more types of PVDC may be mixed to improve melt processability. PVDC can be synthesized by any polymerization method, such as suspension polymerization, emulsion polymerization, or solution polymerization.

[0018] In particular, when the other monomer copolymerizable with vinylidene chloride is vinyl chloride, from the viewpoints of melt processability, gas barrier properties, etc., the PVDC is preferably a copolymer of 60 to 95% by mass of vinylidene chloride and 5 to 40% by mass of vinyl chloride, more preferably a copolymer of 63 to 90% by mass of vinylidene chloride and 10 to 37% by mass of vinyl chloride, even more preferably a copolymer of 66 to 85% by mass of vinylidene chloride and 15 to 34% by mass of vinyl chloride, and particularly preferably a copolymer of 69 to 83% by mass of vinylidene chloride and 17 to 31% by mass of vinyl chloride.

[0019] [Resin made of ethylene-vinyl acetate copolymer] In the vinylidene chloride resin composition according to the present disclosure, the amount of the resin composed of an ethylene-vinyl acetate copolymer is 2 to 3 parts by mass per 100 parts by mass of the polyvinylidene chloride resin. When the amount is 2 parts by mass or more, a filled package produced using a stretched film obtained from the vinylidene chloride resin composition is less likely to be incompletely opened when the outer edge of the filled package, which is made of two overlapping two-layer films, is pinched with the fingers to open it, even when the two films arranged radially inside are welded together with the two films arranged radially outside. When the amount is 3 parts by mass or less, the oxygen gas barrier property of the filled package produced using the resin film obtained from the vinylidene chloride resin composition tends to be inhibited from decreasing.

[0020] In the ethylene-vinyl acetate copolymer, the concentration of structural units derived from vinyl acetate is preferably 16% by mass or more and 19% by mass or less, more preferably 16% by mass or more and 18% by mass or less, and most preferably 17% by mass. When the concentration is within these ranges, a filled package manufactured using a stretched film obtained from the vinylidene chloride resin composition is less likely to be incompletely opened even when two films arranged radially inside are welded together with two films arranged radially outside. Furthermore, in an ethylene-vinyl acetate copolymer, if the concentration of structural units derived from vinyl acetate is around 17% by mass, the tensile modulus at 23° C. can be easily adjusted to fall within the most preferred range.

[0021] In the vinylidene chloride resin composition according to the present disclosure, the melt flow rate (hereinafter also referred to as "MFR") of the ethylene-vinyl acetate copolymer is preferably 0.4 g / 10 min or more and less than 0.9 g / 10 min, more preferably 0.7 g / 10 min or more and 0.8 g / 10 min or less, and most preferably 0.8 g / 10 min. When the melt flow rate is within these ranges, a filled package manufactured using a stretched film obtained from the vinylidene chloride resin composition is less likely to be incompletely opened, even when two films arranged radially inside are welded together with two films arranged radially outside. In this specification, the melt flow rate (MFR) is measured in accordance with JIS K 7210.

[0022] The tensile modulus at 23°C of a resin made of ethylene-vinyl acetate copolymer can be adjusted by the molecular weight, polydispersity, branching, copolymer component ratio, etc. For example, in an ethylene-vinyl acetate copolymer, it can be adjusted by changing the concentration of structural units derived from vinyl acetate or the melt flow rate (MFR), which is correlated with the molecular weight. More specifically, when the concentration of structural units derived from vinyl acetate in an ethylene-vinyl acetate copolymer is around 17% by mass, the tensile modulus at 23°C can be easily adjusted to the most preferred range.

[0023] [Additives] The vinylidene chloride resin composition according to the present disclosure may optionally contain various additives, such as heat stabilizers, plasticizers, processing aids, colorants, UV absorbers, pH adjusters, and dispersing aids, which are typically added to cylindrical packaging films used in filled packaging products to improve various properties and moldability. Examples of heat stabilizers include epoxy compounds such as epoxidized vegetable oils, epoxidized animal oils, epoxidized fatty acid esters, and epoxy resin prepolymers; epoxy group-containing resins, and the like, with epoxidized vegetable oils being preferred. The types and amounts of additives may be selected in the same manner as those used in cylindrical packaging films used in filled packaging products. The additives may be used alone or in combination of two or more. Furthermore, some or all of the additives may be incorporated into the monomer composition during the PVDC polymerization process, or may be blended with PVDC after polymerization.

[0024] <Filled packaging body and its manufacturing method> 1 , for example, a filled package according to the present disclosure is a cylindrical stretched vinylidene chloride resin film in which both side edge portions of the stretched vinylidene chloride resin film are overlapped so that the front and back surfaces of the stretched vinylidene chloride resin film face each other and longitudinally sealed, and contents are filled into the cylindrical stretched vinylidene chloride resin film and both end portions are sealed, and the side edge portions of the stretched vinylidene chloride resin film form outer ear portions that protrude in a strip-like shape outside the cylindrical stretched vinylidene chloride resin film. With this filled package, when the outer ear portions are pinched and opened with fingers, incomplete opening is unlikely to occur even if the two films arranged radially inside are welded together with the two films arranged radially outside.

[0025] [Production of Strip-Shaped Stretched Vinylidene Chloride Resin Film] The stretched vinylidene chloride resin film according to the present disclosure is constructed by stacking two films each made of a vinylidene chloride resin composition and having a thickness of 10 μm or more and 300 μm or less. The method for producing a strip-shaped stretched vinylidene chloride resin film for forming a cylindrical stretched vinylidene chloride resin film is not particularly limited. Usually, a sheet-shaped or tubular extruded film is produced by extrusion molding, and the extruded film is stretched to impart heat shrinkability. In the case of a tubular extruded film, the inner sides of the extruded film are overlapped to obtain a two-ply (two-layer laminate) strip-shaped stretched vinylidene chloride resin film having a predetermined width. This can then be cut in the longitudinal direction as necessary to produce a strip-shaped stretched vinylidene chloride resin film having the desired width. The thickness of a single sheet of strip-shaped vinylidene chloride resin stretched film is determined taking into consideration the strength and barrier properties of the film depending on the contents to be filled, but is in the range of 10 μm to 300 μm, and in many cases it is in the range of 12 μm to 100 μm, with the range of 15 μm to 80 μm being widely adopted. When a cylindrical stretched vinylidene chloride resin film is to be printed, the resulting strip-shaped stretched vinylidene chloride resin film may be printed.

[0026] [Vertical seal portion extending in the longitudinal direction] The longitudinally extending vertical seal portion provided on the tubular stretched vinylidene chloride resin film is formed by winding a strip-shaped stretched vinylidene chloride resin film into a cylindrical shape so that the front and back surfaces of both longitudinally extending edge portions overlap and face each other to form a tubular film, and then continuously sealing (welding) both edge portions of the tubular film in the longitudinal direction (longitudinal direction) using a conventional method such as high-frequency dielectric heating to form the tubular stretched vinylidene chloride resin film. In this case, as shown in Fig. 2, for example, the vertical seal portion may be formed by welding together two films arranged radially inside and two films arranged radially outside. The vertical seal portion is provided over the entire longitudinal length of the tubular stretched vinylidene chloride resin film, thereby allowing the contents filled and enclosed in the tubular stretched vinylidene chloride resin film to be preserved in a sealed state. The width of the longitudinal seal portion provided on the cylindrical vinylidene chloride resin stretched film and extending in the longitudinal direction can be determined appropriately.

[0027] [Longitudinal outer ear portion] The longitudinally extending outer ears provided on the tubular stretched vinylidene chloride resin film in this disclosure refer to unsealed longitudinal sections of the tubular stretched vinylidene chloride resin film, which are formed by sealing (welding) both side edges of the tubular stretched vinylidene chloride resin film in the longitudinal direction (longitudinal direction) according to a conventional method, but leaving the longitudinally exposed edges of the side edges perpendicular to the longitudinal direction unsealed. The width of the outer ears is typically 1 mm to 10 mm, and in many cases 2 mm to 6 mm. The longitudinally extending outer ears (unsealed sections) are typically formed with a uniform width throughout the entire longitudinal length of the tubular stretched vinylidene chloride resin film, but may be formed with different widths. The filled package of the present disclosure has an outer ear portion and a vertical seal portion in which a tubular vinylidene chloride-based resin stretched film extends in the longitudinal direction, and can be opened by pinching and pulling the outer ear portion to peel off the vertical seal portion. The outer ear portion extending in the longitudinal direction may be printed, and may have scars, indentations, cuts, notches, through holes, blind holes, etc.

[0028] [Convergence at both ends in the longitudinal direction] The filled package of the present disclosure comprises a tubular stretched vinylidene chloride resin film with outer ears and vertical seals extending in the longitudinal direction and with both longitudinal ends gathered. That is, the filled package of the present disclosure is formed by filling the tubular stretched vinylidene chloride resin film with contents such as processed food and then gathering both longitudinal ends of the tubular stretched vinylidene chloride resin film, thereby allowing the contents to be stored in a sealed state. The gathering of both longitudinal ends of the tubular stretched vinylidene chloride resin film can be achieved by using a method for gathering both longitudinal ends that has traditionally been used for tubular stretched vinylidene chloride resin films provided in filled packages, such as metal wire clips such as aluminum wire clips, horizontal seal films (clip tape), or other means.

[0029] [Contents filled and sealed in a cylindrical vinylidene chloride resin stretched film] The contents filled and sealed in the cylindrical vinylidene chloride resin stretched film provided in the filled packaging body of the present disclosure are not particularly limited, and contents that are conventionally filled in filled packaging bodies, such as solid or paste-like processed foods such as sausage, cheese, butter, hamburger steak, uriwara (sweet bean paste), yokan (sweet bean jelly), and jelly, can be used.Furthermore, contents other than food, such as construction materials such as caulking materials and cosmetics, can also be used. The composition and shape of the filling can be selected as appropriate. Particularly preferred fillings include fish sausages made by blending fish paste with ordinary additives such as oil, salt, and starch.

[0030] [Inclusions] Vertical sealing by high-frequency dielectric heating can be performed by sandwiching both side edges of overlapping stretched vinylidene chloride resin films between an outer electrode disposed radially outward and an inner electrode disposed radially inward, as shown in Fig. 3. In this case, as shown in Fig. 3, by placing an intermediate material that is not sealed by high-frequency dielectric heating between the inner electrode and the stretched vinylidene chloride resin film, the ease of opening the film can be further improved. The reason for this is not entirely clear, but it is thought that this is because the orientation and dispersion state of the resin consisting of ethylene-vinyl acetate copolymer in the vinylidene chloride resin stretched film in the vertical seal section changes compared to when there is no inclusion. The inclusions may be, for example, glass cloth tape or fluororesin tape having a thickness of 10 μm to 300 μm. Alternatively, other materials that do not generate much heat due to high-frequency dielectric heating (such as polyethylene, polypropylene, polyamide, polyimide, cellulose, polyester, or polyacetal tapes or films, ceramics, or glass fibers) may be used as the inclusions, and the internal electrodes may be coated with these materials. [Example]

[0031] The present disclosure will be described in more detail below with reference to examples and comparative examples, but the present disclosure is not limited to these examples.

[0032] [Openability] The openability of the filled package of the present disclosure was evaluated by the following method, and the results are shown in Table 1. Ten subjects each opened five filled packages (total number: 50) by pinching the outer edge of the vertical seal of the filled package with their fingers. The opening rate was calculated using the formula below as the percentage of the two films located radially outward that peeled off from the vertical seal. Opening rate (%) = (number of packages in which the two outermost films peeled from the vertical seal) / 50 x 100 (rounded to the first decimal place) A: The opening rate was between 81% and 100%, and the openability was extremely good. B: The opening rate was 61% or more and 80% or less, and the openability was good. C: The opening rate was 41% or more and 60% or less, and the openability was poor. D: The opening rate was 40% or less, and the openability was extremely poor.

[0033] [Tensile modulus] The tensile modulus of elasticity of the resin made of ethylene-vinyl acetate copolymer was measured by the following method. The measurement sample was prepared by heating a resin made of ethylene-vinyl acetate copolymer at 170°C for 1 minute in a 500 μm thick mold, pressing it at a pressure of 5 MPa, holding it at 170°C for 1 minute, and then cooling it to 25°C. This pressed sheet was cut into strips with a width of 10 mm (number of samples: 5), and a tensile test was carried out under the following conditions in accordance with JIS K 7161. The strain (deformation amount / distance between chucks) was 0.05 × 10 -2 to 0.25 x 10 -2 The stress values up to 1000 kJ / s were linearized using the least squares method to determine the slope (stress / strain), and the average value of five tests (number of samples: 5) was taken as the tensile modulus (MPa). *Tensile test conditions Testing machine: A&D Co., Ltd., Tensilon RTG-1210 Temperature: 23℃ Chuck distance: 50mm Tensile speed: 5 mm / min Number of samples: 5

[0034] Example 1 (Matrix film manufacturing) A vinylidene chloride resin composition was obtained by blending 100 parts by mass of a polyvinylidene chloride resin consisting of a mixture of 85 parts by mass of a copolymer polymerized at a monomer charge mass ratio (VD / VC) of 81 / 19, a polymerization temperature of 34°C to 49°C, and a polymerization time of 44 hours, with 15 parts by mass of a copolymer polymerized at a VD / VC ratio of 71 / 29, a polymerization temperature of 43°C to 58°C, and a polymerization time of 37 hours. A total of 7.8 parts by mass of acetyl tributyl citrate (ATBC), dibutyl sebacate (DBS), and epoxidized vegetable oil was added to the resulting mixture. 1.83 parts by mass of an epoxy group-containing polymer, an antioxidant, a surfactant, erucic acid amide, and calcium carbonate were then added, and finally, 2.5 parts by mass of an ethylene-vinyl acetate copolymer having a tensile modulus at 23°C of 44 MPa was added. The mixture was melt-extruded using a 40 mm diameter extruder to obtain a vinylidene chloride resin composition. Next, a tubular film was formed by biaxially stretching the film by inflation at room temperature under conditions of 2.5 times in the MD (machine direction) and 4.1 times in the TD (transverse direction), and then folded to form a flat two-ply film (two layers) to obtain a vinylidene chloride resin stretched film a (two-layer laminate film) with a total thickness of 40 μm (the thickness of two 20 μm films).

[0035] (Manufacturing of filled packaging) A base film (stretched vinylidene chloride resin film a) cut to a width of 68 mm was placed in an automatic filling and packaging machine (Kureha Corporation, product name: KAP3000 Automatic Filling and Packaging Machine). This base film was wound into a cylindrical shape so that the front and back surfaces of both longitudinally extending edge portions overlapped each other, forming a cylindrical PVDC film. While the cylindrical PVDC film was running downward, the overlapping both edge portions of the cylindrical PVDC film were passed between a seal electrode (an external electrode with a semicircular tip having a radius of 1 mm) and a ground electrode (internal electrode) of a high-frequency dielectric heating device to which high-frequency power based on a predetermined voltage and current was applied (the force pressing the external electrode against the internal electrode was 4 N). This welded the two films positioned radially inside the both edge portions of the cylindrical PVDC film together with the two films positioned radially outside, forming a cylindrical PVDC film with 6 mm-wide outer edges and vertical seal portions extending longitudinally. Next, the tubular PVDC film was filled with fish sausage minced meat from a filling device, and then both longitudinal ends of the tubular PVDC film were bundled with clip tape and cut to the specified length to produce a filled package with a circumference of 56 mm and a length of 195 mm. When forming the base film into a cylindrical shape, the conditions were adjusted so that the folded width (half the circumference) was 28 mm, the cut length (the length measured in the longitudinal direction after removing the contents from the filled package and flattening the tubular PVDC film) was 195 mm, and the mass was 35 g. The resulting filled package was subjected to a temperature of 120°C and a pressure of 2.0 kg / cm 2 The container was left to stand in a retort oven at 100°C (gauge pressure) for 10 minutes to carry out retort heat sterilization, and then removed to prepare a sample for evaluating the ease of opening.

[0036] Comparative Example 1 A stretched vinylidene chloride resin film b was obtained by film formation in the same manner as in Example 1, except that an ethylene-vinyl acetate copolymer having a tensile modulus at 23° C. of 34 MPa was used instead of an ethylene-vinyl acetate copolymer having a tensile modulus at 23° C. of 44 MPa. A filled package was also obtained in the same manner as in Example 1, except that a stretched vinylidene chloride resin film b was used instead of the stretched vinylidene chloride resin film a.

[0037] Comparative Example 2 A stretched vinylidene chloride resin film c was obtained by film formation in the same manner as in Example 1, except that an ethylene-vinyl acetate copolymer having a tensile modulus at 23° C. of 78 MPa was used instead of the ethylene-vinyl acetate copolymer having a tensile modulus at 23° C. of 44 MPa. A filled package was also obtained in the same manner as in Example 1, except that the stretched vinylidene chloride resin film c was used instead of the stretched vinylidene chloride resin film a.

[0038] Comparative Example 3 A stretched vinylidene chloride resin film d was obtained by film formation in the same manner as in Example 1, except that the ethylene-vinyl acetate copolymer having a tensile modulus of elasticity of 44 MPa at 23°C was not added. A filled package was also obtained in the same manner as in Example 1, except that the stretched vinylidene chloride resin film d was used instead of the stretched vinylidene chloride resin film a.

[0039] [Table 1]

[0040] (Note) VAc: concentration of structural units derived from vinyl acetate. "%" in Table 1 means % by mass. phr: represents the unit (parts by mass) of the amount of resin made of ethylene-vinyl acetate copolymer added, based on 100 parts by mass of polyvinylidene chloride resin.

[0041] As can be seen from Table 1, the vinylidene chloride resin composition according to the present disclosure has a resin composed of an ethylene-vinyl acetate copolymer whose tensile modulus at 23°C is 43 MPa or more and 45 MPa or less, and the amount of the resin composed of an ethylene-vinyl acetate copolymer is 2 parts by mass or more and 3 parts by mass or less. Therefore, it is clear that a filled package manufactured using a stretched film obtained from the vinylidene chloride resin composition is unlikely to be incompletely opened, even when two films arranged radially inside and two films arranged radially outside are welded together. [Explanation of symbols]

[0042] S:Filled packaging 1: Cylindrical vinylidene chloride resin stretched film 21: Vertical seal part 22: External ear part 3A, 3B: Both ends 41: Two films arranged radially outward 41A: Surface layer (the outermost film in the radial direction) 42: Two films arranged radially inward 51 :External electrode 52: Internal electrode 61 :Inclusion

Claims

1. A vinylidene chloride resin composition containing a polyvinylidene chloride resin and a resin made of an ethylene-vinyl acetate copolymer, the tensile modulus of the resin made of ethylene-vinyl acetate copolymer at 23°C is 43 MPa or more and 45 MPa or less, In the vinylidene chloride resin composition, the amount of the resin composed of the ethylene-vinyl acetate copolymer is 2 parts by mass or more and 3 parts by mass or less per 100 parts by mass of the polyvinylidene chloride resin, In the resin made of ethylene-vinyl acetate copolymer, The concentration of structural units derived from vinyl acetate in the ethylene-vinyl acetate copolymer is 16% by mass or more and 19% by mass or less, and The vinylidene chloride resin composition has an ethylene-vinyl acetate copolymer having a melt flow rate of 0.4 g / 10 min or more and less than 0.9 g / 10 min.

2. A vinylidene chloride resin stretched film comprising two laminated films each having a thickness of 10 μm or more and 300 μm or less, each made of the vinylidene chloride resin composition according to claim 1.

3. A filled package in which both side edge portions of the stretched vinylidene chloride resin film according to claim 2 are overlapped with each other so that the front and back surfaces of the stretched vinylidene chloride resin film face each other and are longitudinally sealed in a cylindrical shape, and the contents are filled into the stretched vinylidene chloride resin film and both end portions are sealed, A filled package in which the side edge portions of the stretched vinylidene chloride resin film form outer ear portions in the form of strips that protrude outside the tubular stretched vinylidene chloride resin film.

4. 4. The filled package according to claim 3, wherein the vertical seal portion is formed by welding together two films arranged radially inside and two films arranged radially outside.

Images