Wrap film

Abstract

To provide a wrap film that is easy to pick up and recover a cut end face when the film is cut in the middle when the wrap film is pulled out from a decorative box, and easy to reuse.SOLUTION: The wrap film includes polyvinylidene chloride resin. A molecular chain orientation ratio that is calculated by the following formula (1) when polarization Raman is measured is 0.3 to 3.0. A molecular chain orientation ratio=CCl2-derived peak (630-680 cm-1) intensity in an MD direction (A value) / CCl2-derived peak (630-680 cm-1) intensity in a TD direction (C value) ... (1)SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a wrap film and a wrap film roll using the same. [Background technology]

[0002] Traditionally, wrap films have been used in many ordinary households as wrap films for food, etc., due to their excellent properties, such as adhesion to other films and to substrates, gas barrier properties against gases such as water vapor and oxygen, and ease of cutting when used in decorative boxes. Household wrap films are primarily used to store food in refrigerators or freezers, or to overlap when heating food in containers in a microwave oven.

[0003] As such a wrap film, for example, Patent Document 1 describes a wrap film containing a polyvinylidene chloride resin, which is The following formula (1): Δn=n x -n y =Re / d (1) (In the formula, n x represents the refractive index in the slow axis direction in the film plane, and n y represents the refractive index in the direction perpendicular to the slow axis direction in the film plane, Re represents the in-plane retardation of the film (unit: nm), and d represents the film thickness (unit: nm). The birefringence Δn calculated by the following formula (1a): 0.0003≦Δn≦0.0013 (1a) The condition expressed by The following formula (2): ΔP=(n x +n y ) / 2-n z (2) (In the formula, n x represents the refractive index in the slow axis direction in the film plane, and n y represents the refractive index in the direction perpendicular to the slow axis direction in the film plane, and n z represents the refractive index in the thickness direction of the film) The plane orientation ΔP calculated by the following formula (2a): -0.0120≦ΔP≦-0.0102 (2a) The present invention discloses a wrap film that satisfies the conditions expressed by the following formula: Furthermore, for example, Patent Document 2 discloses a wrap film having a tensile strength in the direction perpendicular to the machine direction (TD) of 100 MPa or more, a tensile elongation of 100% or less, a tensile modulus of elasticity of 280 MPa or more, and a tensile modulus of elasticity in the machine direction (MD) of 380 MPa or more. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2016-189987 [Patent Document 2] Japanese Patent Application Publication No. 2019-43679 Summary of the Invention [Problem to be solved by the invention]

[0005] However, as shown in Figure 2, for example, when pulling out wrap film 17 from presentation box 14, or when pulling out the film from presentation box 14 and cutting the film, the film may not be cut cleanly and may tear along the way, or may not be cut perpendicular to the direction in which the film is pulled out (MD), leaving part of cut edge 18 protruding. If the protruding cut edge 18 is pinched to correct this, the film is likely to deform in the TD direction (perpendicular to MD), and if the breaking strength is low, the pinched film may tear again, making it difficult to repair. Furthermore, if the breaking strength of the film is reduced, the film may break when the wrap film is used repeatedly, making it difficult to reuse. The wrap films described in Patent Documents 1 and 2 do not address these issues and there is room for improvement.

[0006] Therefore, an object of the present invention is to provide a wrap film that is easy to grasp and recover at the cut end surface when the wrap film is torn in the middle when being pulled out from a decorative box, and that is easy to reuse. [Means for solving the problem]

[0007] As a result of extensive research to overcome these problems, the inventors discovered that a wrap film containing a polyvinylidene chloride resin and having a molecular chain orientation ratio that meets certain conditions is easy to grip at the cut edge of the wrap film when the wrap film is torn while being pulled out of the gift box, and is less likely to tear when the cut edge is gripped, making it easier to repair (restore) a torn wrap film, and is less likely to break even when used repeatedly, making it easier to reuse, which led to the completion of the present invention.

[0008] That is, the present invention is as follows. [1] Contains polyvinylidene chloride resin, A wrap film having a molecular chain orientation ratio calculated by the following formula (1) in polarized Raman measurement of 0.3 to 3.0; Molecular chain orientation ratio = MD direction CCl2-derived peak (630-680 cm -1 ) Intensity (A value) / CCl2-derived peak in the TD direction (630-680 cm -1 ) Strength (C value)···(1). [2] Further included are compounds containing methylene groups (CH2), The wrap film according to [1], wherein the molecular chain orientation in the TD direction calculated by the following formula (2) when measuring polarized Raman spectroscopy in the TD direction is 2.0 to 5.8; Molecular chain orientation in the TD direction = Peaks derived from CCl2 in the MD direction (630-680 cm -1 ) Intensity (A value) / MD direction CH2-derived peak (2840-2890 cm -1 ) Strength (D value)···(2). [3] The wrap film according to [1] or [2], which has a tensile breaking strength in the TD direction of 100 MPa or more. [4] The wrap film according to any one of [1] to [3], which has a tensile elongation at break in the TD direction of 100% or less. [5] The wrap film according to any one of [1] to [4], which has a thickness of 6 to 18 μm. [6] A roll in which the wrap film according to any one of [1] to [5] is wound around a core. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a wrap film that is easy to grasp and recover at the cut end surface when the wrap film is torn in the middle when being pulled out from a decorative box, and that is easy to reuse. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a schematic diagram of an example of a manufacturing process for the wrap film of the present invention. [Figure 2] FIG. 2 is a schematic diagram of an example of a wrap film container containing a wrap film. [Figure 3] FIG. 10 is a schematic diagram of an example of a sampling position when the wrap film is pulled out. [Figure 4] FIG. 1 is a schematic diagram of an example in which a measurement sample is placed on a slide glass. [Figure 5] FIG. 1 is a schematic diagram of an example of a Raman microscope image. [Figure 6] FIG. 1 is a schematic diagram of an example in which a measurement sample is placed on a slide glass and rotated. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, a mode for carrying out the present invention (hereinafter referred to as "the present embodiment") will be described in detail. Note that the present invention is not limited to the following embodiment, and various modifications can be made within the scope of the gist thereof.

[0012] The wrap film of this embodiment contains a polyvinylidene chloride resin, and has a molecular chain orientation ratio calculated by the following formula (1) when measured using polarized Raman spectroscopy of 0.3 to 3.0. Molecular chain orientation ratio = MD direction CCl2-derived peak (630-680 cm -1 ) Intensity (A value) / CCl2-derived peak in the TD direction (630-680 cm -1 ) Strength (C value) (1) Because the wrap film of this embodiment has these characteristics, if the film tears when pulled out from the gift box, the cut edge is easy to grip and repair, making it easy to reuse when used repeatedly. In this embodiment, each molecular chain orientation can be measured by the method described in the examples below.

[0013] <Polyvinylidene chloride resin> The wrap film of this embodiment contains a polyvinylidene chloride resin. The polyvinylidene chloride resin used in the present embodiment is not particularly limited as long as it contains a structural unit derived from vinylidene chloride. In addition to the structural unit derived from vinylidene chloride, one or more monomers copolymerizable with vinylidene chloride, such as vinyl chloride, acrylic acid esters such as methyl acrylate and butyl acrylate; methacrylic acid esters such as methyl methacrylate and butyl methacrylate; acrylonitrile; and vinyl acetate, may be copolymerized.

[0014] The weight-average molecular weight (Mw) of the polyvinylidene chloride resin is preferably 80,000 to 200,000, more preferably 90,000 to 180,000, and even more preferably 100,000 to 170,000. Having a weight-average molecular weight (Mw) within the above range tends to further improve the mechanical strength of the wrap film. A vinylidene chloride resin having a weight-average molecular weight within the above range can be obtained by, for example, controlling the charging ratio of vinylidene chloride monomer to vinyl chloride monomer, the amount of polymerization initiator, or the polymerization temperature. In this embodiment, the weight-average molecular weight (Mw) can be determined by gel permeation chromatography (GPC) using a standard polystyrene calibration curve.

[0015] When the polyvinylidene chloride resin is a copolymer resin, the proportion of vinylidene chloride-derived structural units is not particularly limited, but preferably contains 72 to 93 mass% of vinylidene chloride-derived structural units, and more preferably 81 to 90 mass%. When the vinylidene chloride-derived structural units are 72 mass% or more, the glass transition temperature of the polyvinylidene chloride-based resin is low and the film becomes soft, which tends to reduce film tearing even when used in low-temperature environments such as winter. On the other hand, when the vinylidene chloride-derived structural units are 93 mass% or less, a significant increase in crystallinity is suppressed, which tends to suppress deterioration of molding processability during film stretching. In particular, wrap films made of polyvinylidene chloride resins containing 72% by mass or more of structural units derived from vinylidene chloride tend to undergo physical deterioration due to the formation and growth of microcrystals when stored or distributed at high temperatures, such as in the summer, which can result in tearing problems when the film is used, making the effects of the present invention even more pronounced.

[0016] The contents of the vinylidene chloride-derived structural units and the vinyl chloride-derived structural units are not particularly limited, but can be measured, for example, using a high-resolution proton nuclear magnetic resonance analyzer. More specifically, the re-precipitated filtrate of the wrap film is obtained according to the following procedure. Dissolve 0.5 g of sample in 10 mL of THF (tetrahydrofuran), add approximately 30 mL of methanol to precipitate the resin, then filter to separate the precipitate and dry it. The reprecipitated product thus obtained is dried under vacuum, and a 5% by mass solution is dissolved in deuterated tetrahydrofuran. The solution is subjected to H-NMR measurement at a measurement atmosphere of 23±2°C and 50±10% RH (accumulation number: 512). The vinylidene chloride-derived structural units and vinyl chloride-derived structural units are calculated using the characteristic chemical shifts based on tetramethylsilane in the obtained spectrum.

[0017] Hereinafter, the structural unit derived from vinylidene chloride (-CH2-CCl2-) will be referred to as A, and the structural unit derived from vinyl chloride (-CH2-CHCl-) will be referred to as B, and signals 1, 2, and 3 obtained on the spectrum will be assigned as follows: Signal 1 (approximately 5.2 to 4.5 ppm) is assigned to the CH signal of B (methine (CH) group of the structural unit derived from vinyl chloride). Signal 2 (approximately 4.2 to 3.8 ppm) is assigned to the CH2 signal of one of the A's in AA (the methylene (CH2) group of the structural unit derived from vinylidene chloride). Signal 3 (approximately 3.5 to 2.8 ppm) is assigned to the CH2 signal of A in both AB and BA (methylene (CH2) group of the structural unit derived from vinylidene chloride).

[0018] The molar fractions of the structural units are calculated from the spectral area values ​​of these signals (areas of the signals in the NMR spectrum). Each molar fraction is expressed as follows: Mole fraction of A (mol%): P(A) Molar fraction of B (mol%): P(B)

[0019] From the area values ​​(areas of peaks in the NMR spectrum) of signals 1, 2, and 3 assigned as above, the integral values ​​of the signals on the spectrum are assigned as follows: The integral value of signal 1 (approximately 5.2 to 4.5 ppm) is calculated for one 1H of B. The integral value of signal 2 (approximately 4.2 to 3.8 ppm) is calculated for two 1H atoms of A. The integral value of signal 3 (approximately 3.5 to 2.8 ppm) is calculated as four 1H of A.

[0020] Each mole fraction is calculated using the following formula: P(A) + P(B) = 100

[0021] P(A) and P(B) are calculated using the following formula: P(B):P(A) = Signal 1 integral:(Signal 2 integral + Signal 3 integral / 2) / 2 P(A)=100-P(B)

[0022] The molecular weight of A, a structural unit derived from vinylidene chloride (-CH2-CCl2-), was set to 97.0, and the molecular weight of B, a structural unit derived from vinyl chloride (-CH2-CHCl-), was set to 62.5, and the mass fractions were calculated using the following formula. Each mass fraction is expressed as follows: Mass fraction of A (mass%): Q(A) Mass fraction of B (mass%): Q(B) Q(A) = (P(A) × 97.0) / (P(A) × 97.0 + P(B) × 62.5 ) × 100 Q(B) = 100 - Q(A)

[0023] The content of polyvinylidene chloride resin is preferably 77 to 94 mass%, more preferably 85 to 94 mass%, of the total amount of the wrap film. By keeping the content of vinylidene chloride resin within this range, the film can be prevented from becoming easily stretched due to the plasticizing effect of additives, etc., and the cuttability of the film tends to be further improved.

[0024] The method for measuring the content of each component in a wrap film varies depending on the object to be analyzed. For example, the content of vinylidene chloride resin can be obtained by vacuum drying the reprecipitated filtrate of the wrap film and measuring its mass. On the other hand, the content of epoxidized vegetable oil can be obtained, for example, by analyzing the reprecipitated filtrate of the wrap film using gel permeation chromatography or by using NMR. Furthermore, the content of citrate esters and dibasic acid esters can be obtained by extracting additives from the wrap film using an organic solvent such as acetone and analyzing them with gas chromatography.

[0025] The wrap film of this embodiment may contain various additives as needed in addition to the polyvinylidene chloride resin. The additives are not particularly limited and include, for example, known stabilizers such as epoxidized vegetable oils, and known plasticizers such as citrate esters and dibasic acid esters.

[0026] <Epoxidized vegetable oil> The wrap film of this embodiment preferably contains an epoxidized vegetable oil from the viewpoint of suppressing color change in the wrap film. The epoxidized vegetable oil also acts as a stabilizer for vinylidene chloride resin extrusion processing.

[0027] The epoxidized vegetable oil is not particularly limited, but examples thereof include those generally produced by epoxidizing edible oils and fats.Specific examples thereof include, but are not particularly limited to, epoxidized soybean oil (ESO) and epoxidized linseed oil.Of these, ESO is preferred because it tends to prevent deterioration in the ease of pulling out the wrap film from the packaging box when the wrap film is stored at high temperatures.

[0028] When the wrap film of this embodiment contains an epoxidized vegetable oil, the content is not particularly limited, but from the viewpoint of suppressing color change in the wrap film and preventing stickiness due to bleeding, the content is preferably 0.5 to 3.0 mass % relative to the vinylidene chloride resin, and more preferably 1.0 to 2.0 mass %.

[0029] The method for measuring the content of epoxidized vegetable oil using NMR follows the procedure below. Weigh out 50 mg of sample, dissolve in a heavy solvent (solvent: deuterated THF, internal standard: dimethyl terephthalate, volume: 0.7 ml), and measure by 400 MHz proton NMR (number of integrations: 512). The ratio of the integration value from 2.23 to 2.33 ppm to the integration value from 8.05 to 8.11 ppm is taken as the integral ratio, and the quantitative value is calculated using the absolute calibration curve method. Integral ratio = integral value (2.23-2.33 ppm) / integral value (8.05-8.11 ppm)

[0030] The epoxidized vegetable oil content was measured using gel permeation chromatography according to the following procedure. Weigh 3 g of sample into a tall beaker, add 30 ml of THF, stir with a stirrer, and heat (50°C x 4 min) until completely dissolved. While stirring with a stirrer, slowly add methanol (170 ml) dropwise to re-precipitate. Once all the methanol has been added, filter through a glass filter using suction. The filtrate is concentrated and vacuum dried, then placed in a 10 ml measuring flask and made up to volume with chloroform. Filter the chloroform solution through a syringe filter (PTFE, pore size 0.45 μm) and analyze by GPC. Prepare three levels of standard samples by weighing ESO into a measuring flask and making up to volume with chloroform. Filter through a syringe filter in the same way as the sample and analyze by GPC. Create a calibration curve by plotting the GPC analysis and the standard sample concentration. The GPC area of ​​the sample is fitted to the calibration curve to calculate the concentration, and the ESO quantitative value is calculated.

[0031] <Citrate esters and dibasic acid esters> From the viewpoint of molding processability, the wrap film of this embodiment preferably contains at least one compound selected from the group consisting of citrate esters and dibasic acid esters.

[0032] The citrate ester used in the wrap film of this embodiment is not particularly limited, but examples include triethyl citrate, tributyl citrate, acetyl triethyl citrate, acetyl tributyl citrate (hereinafter also referred to as "ATBC"), tri-n-(2-ethylhexyl) acetyl citrate, etc. Among these, ATBC is preferred because it has a high plasticizing effect on vinylidene chloride resins, and even a small amount tends to sufficiently plasticize the resin and improve moldability.

[0033] The dibasic acid ester contained in the wrap film of this embodiment is not particularly limited, but examples include adipic acid esters such as dibutyl adipate, di-n-hexyl adipate, di-2-ethylhexyl adipate, and dioctyl adipate; azelaic acid esters such as di-2-ethylhexyl azelaate and octyl azelaate; and sebacic acid esters such as dibutyl sebacate (hereinafter also referred to as "DBS") and di-2-ethylhexyl sebacate. Of these, DBS is preferred because it has a high plasticizing effect on polyvinylidene chloride resins and tends to sufficiently plasticize the resin even with a small amount, improving moldability.

[0034] The total content of the citrate ester and dibasic acid ester is not particularly limited, but from the viewpoint of imparting better molding processability and preventing excessive adhesion of the wrap film when the additive content is high, it is preferably 3.0 to 8.0 mass%, more preferably 3.0 to 7.0 mass%, even more preferably 3.0 to 5.5 mass%, and particularly preferably 3.5 to 5.5 mass%, relative to the polyvinylidene chloride resin.

[0035] In particular, when the wrap film of this embodiment contains 3% by mass or more of citrate ester or dibasic acid ester, the mobility of the molecular chains of the polyvinylidene chloride resin increases, making it more likely to undergo rearrangements such as the formation and growth of microcrystals, and making it more susceptible to physical deterioration when exposed to high temperatures.In addition, the film becomes more stretchable, making it more difficult for a cutting blade to penetrate the film, which tends to reduce cutting ability, making the effects of the present invention more pronounced.

[0036] <Acetylated fatty acid glycerides> The wrap film of this embodiment may contain an acetylated fatty acid glyceride as a plasticizer. The acetylated fatty acid glyceride is not particularly limited, but examples include acetylated caprylic acid glyceride, acetylated capric acid glyceride, acetylated lauric acid glyceride, acetylated myristate acid glyceride, acetylated palm kernel oil glyceride, acetylated coconut oil glyceride, acetylated castor oil glyceride, and acetylated hydrogenated castor oil glyceride.

[0037] The acetylated fatty acid glyceride may be any of acetylated monoglycerides of fatty acids, acetylated diglycerides of fatty acids, and acetylated triglycerides of fatty acids. For example, the acetylated lauric acid glyceride includes acetylated monoglycerides of lauric acid, acetylated diglycerides of lauric acid (DALG: diacetyl lauroylglycerol), and acetylated triglycerides of lauric acid. Among these, acetylated lauric acid glycerides are preferred, and acetylated diglycerides of lauric acid are more preferred.

[0038] The content of acetylated fatty acid glyceride is preferably 3.0 to 8.0% by mass, more preferably 3.5 to 7.0% by mass, and even more preferably 4.0 to 6.0% by mass, relative to the total amount of the wrap film. When the content of acetylated fatty acid glyceride is within the above range, molding processability tends to be further improved. Note that the method for measuring the content of each component in the wrap film varies depending on the object to be analyzed. The content of acetylated fatty acid glyceride can be obtained by extracting additives from the wrap film using an organic solvent such as acetone, followed by gas chromatography analysis.

[0039] The total content of at least one compound selected from the group consisting of citric acid esters, dibasic acid esters, and acetylated fatty acid glycerides is preferably 3.0 to 8.0% by mass, more preferably 3.5 to 7.0% by mass, and even more preferably 4.0 to 6.6% by mass, relative to the total amount of wrap film. Having the total content of citric acid esters, dibasic acid esters, and acetylated fatty acid glycerides within the above ranges further improves molding processability and tends to suppress excessive stickiness due to bleeding of wrap film when the epoxidized vegetable oil content is high.

[0040] [Other additives] In addition to the polyvinylidene chloride resin described above, the wrap film of this embodiment may contain, as necessary, known additives used in food packaging materials, such as plasticizers, stabilizers, weather resistance improvers, colorants such as dyes or pigments, anti-fogging agents, antibacterial agents, lubricants, nucleating agents, etc. These may be used alone or in combination of two or more.

[0041] The plasticizer is not particularly limited, but specific examples include dimethyl phthalate, diethyl phthalate, dioctyl phthalate, glycerin, glycerin esters, wax, liquid paraffin, and phosphate esters.

[0042] The stabilizer is not particularly limited, but specific examples include antioxidants such as 2,5-t-butylhydroquinone, 2,6-di-t-butyl-p-cresol, 4,4'-thiobis-(6-t-butylphenol), 2,2'-methylene-bis-(4-methyl-6-t-butylphenol), octadecyl-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate, and 4,4'-thiobis-(6-t-butylphenol); and heat stabilizers such as laurate, myristate, palmitate, stearate, isostearate, oleate, ricinoleate, 2-ethylhexylate, isodecanoate, neodecanoate, and calcium benzoate.

[0043] The weather resistance improver is not particularly limited, but specific examples include ultraviolet absorbers such as ethylene-2-cyano-3,3'-diphenylacrylate, 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-(2'-hydroxy-3'-t-butyl-5'-methylphenyl)5-chlorobenzotriazole, 2-hydroxy-4-methoxybenzophenone, and 2,2'-dihydroxy-4-methoxybenzophenone.

[0044] The colorant such as a dye or pigment is not particularly limited, but specific examples include carbon black, phthalocyanine, quinacridone, indoline, azo pigments, and red iron oxide.

[0045] The anti-fogging agent is not particularly limited, but specific examples thereof include glycerin fatty acid esters, sorbitan fatty acid esters, polyoxyethylene fatty acid alcohol ethers, polyoxyethylene glycerin fatty acid esters, and polyoxyethylene sorbitan fatty acid esters.

[0046] The antibacterial agent is not particularly limited, but specific examples include silver-based inorganic antibacterial agents.

[0047] The lubricant is not particularly limited, but specific examples include fatty acid hydrocarbon lubricants such as ethylene bisteramide, butyl stearate, polyethylene wax, paraffin wax, carnauba wax, myristyl myristate, and stearyl stearate, higher fatty acid lubricants, fatty acid amide lubricants, and fatty acid ester lubricants.

[0048] The nucleating agent is not particularly limited, but specific examples include metal salts of phosphate esters.

[0049] The content of the above-mentioned other additives is preferably 5.0% by mass or less, more preferably 3.0% by mass or less, even more preferably 1.0% by mass or less, and particularly preferably 0.1% by mass or less, based on the wrap film.

[0050] The wrap film of this embodiment preferably further contains a compound containing a methylene group (CH2). The compound containing a methylene group (CH2) used in this embodiment is not particularly limited, but examples include additives containing a methylene group (CH2) from among the known additives used in food packaging materials, such as plasticizers, stabilizers, weather resistance improvers, colorants such as dyes or pigments, anti-fogging agents, antibacterial agents, lubricants, and nucleating agents, as described above.

[0051] The total content of compounds containing a methylene group (CH2) is preferably 3.0 to 8.0 mass%, more preferably 3.5 to 7.0 mass%, and even more preferably 4.0 to 6.6 mass%, relative to the total amount of the wrap film.

[0052] The wrap film of this embodiment contains a polyvinylidene chloride resin, and has a molecular chain orientation ratio calculated by the following formula (1) when measured using polarized Raman spectroscopy of 0.3 to 3.0. Molecular chain orientation ratio = MD direction CCl2-derived peak (630-680 cm -1 ) Intensity (A value) / CCl2-derived peak in the TD direction (630-680 cm -1 ) Strength (C value)···(1). In the wrap film of this embodiment, by setting the molecular chain orientation ratio to 0.3 or more, the molecular chains are oriented in the TD direction, making it less likely to stretch in the TD direction and increasing the breaking stress, making it easier to pinch the cut edge when a tear occurs. Furthermore, by setting the molecular chain orientation ratio of the wrap film of this embodiment to 3.0 or less, the tear strength in the TD direction is sufficient, making the wrap film less likely to tear. From the same viewpoint, the molecular chain orientation ratio of the wrap film is preferably 0.5 to 3.0, more preferably 0.9 to 3.0, even more preferably 1.6 to 3.0, and particularly preferably 1.9 to 3.0. There are no particular limitations on the method for obtaining a wrap film having a molecular chain orientation ratio within the above range. For example, in the wrap film manufacturing method described below, the difference between the cooling bath temperature and the stretching temperature (stretching temperature - cooling bath temperature) can be adjusted to a specific range (for example, 19°C to 37°C).

[0053] The wrap film of this embodiment preferably further contains a compound containing a methylene group (CH2), and when polarized Raman spectroscopy is measured in the TD direction, the molecular chain orientation in the TD direction calculated by the following formula (2) is 2.0 to 5.8. Molecular chain orientation in the TD direction = Peaks derived from CCl2 in the MD direction (630-680 cm -1 ) Intensity (A value) / MD direction CH2-derived peak (2840-2890 cm -1 ) Strength (D value)···(2). In the wrap film of this embodiment, by setting the molecular chain orientation in the TD to 2.0 or more, the molecular chains are oriented in the TD, making it difficult to stretch in the TD and increasing the breaking stress, so that when a tear occurs, the cut edge is easy to grip. Furthermore, because the breaking stress is high, the wrap film is less likely to break even after repeated use and is easy to reuse. Furthermore, by setting the molecular chain orientation in the TD direction of the wrap film of this embodiment to 5.8 or less, the wrap film has sufficient tensile breaking strength in the TD direction, making it less likely to tear. From the same viewpoint, the molecular chain orientation in the TD direction calculated by the above formula (2) is more preferably 2.3 to 5.8, even more preferably 2.9 to 5.8, even more preferably 3.8 to 5.8, and particularly preferably 4.2 to 5.8.

[0054] The thickness of the wrap film of this embodiment is preferably 5.0 to 18.0 μm, more preferably 5.0 to 15.0 μm, and even more preferably 5.0 to 12.0 μm. When the thickness of the wrap film of this embodiment is within the above range, problems with the film tearing are suppressed, the cuttability is improved, and the adhesion is also improved, which tends to make the wrap film easier to reuse.

[0055] The wrap film of this embodiment preferably has a TD tensile breaking strength X1 (MPa) of 100 or more, preferably in the range of 100≦X1≦300. When the wrap film of this embodiment has a TD tensile breaking strength in the range of 100 MPa or more, it has sufficient strength to break in a direction perpendicular to the TD when cut, and in the case of a wrap wrap for food packaging, vertical tearing when cut is suppressed, and it tends to be easier to reuse even after repeated use. Furthermore, when the wrap film of this embodiment has a TD tensile breaking strength in the range of 300 MPa or less, it does not have too high a strength to break in a direction perpendicular to the TD when cut, and in the case of a wrap wrap for food packaging, vertical tearing when cut tends to be suppressed. From the perspective of practical usability, it is more preferable that X1 be 130≦X1≦300, even more preferably 150≦X1≦300, even more preferably 180≦X1≦300, and particularly preferably 190≦X1≦300. The method for controlling the TD tensile breaking strength within the above range is not particularly limited, but an example thereof is, as described below, a method of increasing the difference between the temperature when the sock extruded from the die is cooled and the temperature when the sock is stretched in the subsequent process in the wrap film manufacturing method. In this case, the cooling bath temperature (cooling bath temperature) is preferably 5°C to 23°C, and the temperature in the stretching process (stretching temperature) is preferably 35°C to 42°C. Here, the stretching temperature refers to the resin temperature of the bubble (10). The difference between the cooling bath temperature and the stretching temperature (stretching temperature - cooling bath temperature) is preferably 19°C to 37°C, more preferably 23°C to 37°C, even more preferably 25°C to 37°C, even more preferably 28°C to 37°C, and particularly preferably 30°C to 37°C. When the difference between the cooling bath temperature and the stretching temperature is within the above range, the TD tensile breaking strength of the wrap film of this embodiment tends to be controlled within the above range. In this embodiment, the tensile strength at break in the TD direction can be measured by the method described in the examples below.

[0056] The wrap film of this embodiment preferably has a TD direction tensile breaking elongation X2 (%) of 100 or less, and preferably 15≦X2≦100. When the wrap film of this embodiment has a TD direction tensile breaking elongation of 100% or less, the film is easily torn when cut, and in the case of a wrap for wrapping food, longitudinal tearing tends to be reduced when cut. When the wrap film of this embodiment has a TD direction tensile breaking elongation of 15% or more, the film stretches appropriately when cut and is easily torn, and in the case of a wrap for wrapping food, longitudinal tearing tends to be reduced when cut. From the perspective of practical usability, it is more preferably 15≦X2≦90, even more preferably 15≦X2≦80, even more preferably 15≦X2≦55, and particularly preferably 15≦X2≦50. There are no particular limitations on the method for controlling the TD tensile breaking elongation within the above range, but an example is a method, as described below, in which, in the wrap film manufacturing method, the difference between the temperature when the sock extruded from the die is cooled and the temperature when it is stretched in the subsequent step is increased. In this case, the cooling bath temperature (cooling bath temperature) is preferably 5°C to 23°C, and the temperature in the stretching step (stretching temperature) is preferably 35°C to 42°C. The difference between the cooling bath temperature and the stretching temperature (stretching temperature - cooling bath temperature) is preferably 19°C to 37°C, more preferably 23°C to 37°C, even more preferably 25°C to 37°C, even more preferably 28°C to 37°C, and particularly preferably 30°C to 37°C. When the difference between the cooling bath temperature and the stretching temperature is within the above range, the TD tensile breaking elongation of the wrap film of this embodiment tends to be controlled within the above range. In this embodiment, the tensile elongation at break in the TD direction can be measured by the method described in the examples below.

[0057] <Wrapping film manufacturing method> Next, an example of a method for producing the wrap film of this embodiment will be described. The method for producing a wrap film containing a polyvinylidene chloride resin can be variously adopted as long as the molecular chain orientation in the TD direction described above can be satisfied, and is not particularly limited. Typically, for example, an inflation film-forming method is adopted. That is, according to this embodiment, a wrap film can be obtained by inflation molding. More preferably, the wrap film of this embodiment can be obtained by stretching a composition containing the above-mentioned polyvinylidene chloride resin at least in the MD direction and then inflation molding it. The inflation film-forming method is not particularly limited, but for example, a polyvinylidene chloride resin composition is melt-extruded into a tubular shape from a circular die, and the outside of the tubular resin is then contacted with a refrigerant such as cold water filled in a storage tank called a cooling tank. During this process, a refrigerant such as mineral oil is injected and stored inside the tubular (cylindrical) resin sandwiched between the die opening and pinch rolls, and the inside of the tubular resin is solidified by contacting the refrigerant such as mineral oil with the refrigerant to form a film. In this specification, the cylindrical resin portion (extrudate) sandwiched between the die opening and the pinch rolls is referred to as a "sock." The refrigerant (liquid) injected into the sock is referred to as a "sock liquid." The sock is folded by the pinch rolls or the like to form a tubular double-ply film, which is referred to as a "parison."

[0058] An example of the inflation film forming method will be described in more detail below. Figure 1 is a conceptual diagram of an example of the method for producing the wrap film of this embodiment.

[0059] First, in the extrusion step, a composition containing a molten polyvinylidene chloride resin is extruded in a tubular shape from the die opening (3) of a circular die (2) by an extruder (1), to form a sock (tubular polyvinylidene chloride resin-containing composition) (4).

[0060] Next, in the cooling and solidifying process, the outside of the sock (4), which is the extruded product, is brought into contact with cold water in a cooling tank (6), and sock liquid (5) is poured into the sock (4) by a conventional method and stored therein, thereby cooling and solidifying the sock (4) from the inside and outside. At this time, the sock (4) is in a state where the sock liquid (5) is applied to its inside. The solidified sock (4) is folded by a first pinch roll (7), and a parison (8), which is a double-ply sheet, is formed. The amount of sock liquid applied is controlled by the pinch pressure of the first pinch roll (7).

[0061] The sock liquid is not particularly limited, but examples thereof include water, mineral oil, alcohols, polyhydric alcohols such as propylene glycol and glycerin, and aqueous solutions of cellulose or polyvinyl alcohol. These may be used alone or in combination of two or more. Furthermore, the sock liquid may contain the above-mentioned weather resistance improvers, anti-fogging agents, antibacterial agents, etc., used in food packaging materials, as long as the effects of this embodiment are not impaired.

[0062] Next, air is injected into the inside of the parison (8), opening it again and making it tubular. The parison (8) is reheated with hot water (not shown) to a temperature suitable for stretching. The hot water adhering to the outside of the parison (8) is squeezed out by a second pinch roll (9). Next, in the inflation process, air is injected into the tubular parison (8) heated to the appropriate temperature to form a bubble (10) by inflation stretching, and a stretched film is obtained.

[0063] The tear strength of wrap film in the MD direction can be controlled by the orientation of the polymer chains that make up the wrap film. By rapidly cooling the sock extruded from the die in a cooling tank, the progress of resin crystallization is further suppressed, and the molecular chains become a uniform amorphous structure. Then, by stretching in the TD direction, crystallization oriented in the molecular chains in the TD direction is promoted.

[0064] In the wrap film manufacturing method of this embodiment, it is preferable that there is a large difference between the temperature when the sock extruded from the die is cooled and the temperature when it is stretched in the subsequent step, and in this case, the cooling bath temperature (cooling bath temperature) is preferably 5°C to 23°C, and the temperature in the stretching step (stretching temperature) is preferably 35°C to 42°C. The difference between the cooling bath temperature and the stretching temperature (stretching temperature - cooling bath temperature) is preferably 19°C to 37°C, more preferably 23°C to 37°C, even more preferably 25°C to 37°C, even more preferably 28°C to 37°C, and particularly preferably 30°C to 37°C. When the difference between the cooling bath temperature and the stretching temperature is within the above range, the molecular chain orientation in the TD direction of the wrap film of this embodiment tends to be able to be controlled within the above-mentioned range.

[0065] The wrap film manufacturing method of this embodiment preferably includes a step of stretching an unstretched sheet in the machine direction and in a direction perpendicular to the machine direction, and the stretching ratios in the MD and TD directions are each independently preferably 4.0 to 6.0 times, more preferably 4.1 to 5.6 times. In particular, the orientation of molecular chains in the TD direction can be controlled by the ratio of the draw ratio between the second pinch roll (9) and the third pinch roll (11) (hereinafter also referred to as the "3rd / 2nd draw ratio") and the draw ratio in the TD direction (hereinafter also referred to as the "TD draw ratio"). In order to orient molecular chains in the TD direction, it is preferable that the TD draw ratio is greater than the 3rd / 2nd draw ratio.

[0066] The cooling and solidifying step is not particularly limited, and known methods can be used. For example, a method of controlling the cooling bath temperature by changing the temperature of the cold water used for cooling and solidifying can be used. In order to promote the orientation of molecular chains in the TD direction, it is preferable to rapidly cool the sock extruded from the die in a cooling bath, thereby further suppressing the progress of crystallization of the resin and giving the molecular chains a uniform amorphous structure. The cooling bath temperature is more preferably 5°C to 23°C. Thereafter, by stretching in the TD direction, crystallization oriented in the molecular chains in the TD direction is promoted.

[0067] The method for controlling the stretch ratio is not particularly limited, and known methods can be used. For example, a method of controlling the stretch temperature by changing the temperature of hot water for reheating can be used. Here, the stretch temperature refers to the resin temperature of the bubble (10). To reduce the stretch ratio, a lower stretch temperature is preferable because the inflation bubble is stabilized at a low stretch ratio. In this case, the stretch temperature is preferably higher than the room temperature for stretching from the viewpoint of the stability of the inflation bubble. The stretching temperature is preferably 35°C or higher, more preferably 35°C to 48°C, even more preferably 35°C to 45°C, and particularly preferably 35°C to 42°C. The stretching temperature is measured at a midpoint in the MD between the point where stretching in the MD and TD directions is completed and the point where winding begins.

[0068] The stretched film is then folded by a third pinch roll (11) to form a double-ply film (12). The double-ply film (12) is then taken up by a take-up roll (13). The film is then slit and peeled off to form a single film (single peeling). Finally, the film is wound up around a core such as a cardboard tube, and a paper-tube wrapped wrap film roll is obtained.

[0069] Here, the orientation of molecular chains in the TD direction can be controlled by adjusting the ratio between the draw ratio of the second pinch roll (9) and the third pinch roll (11) and the draw ratio in the TD direction.

[0070] The above description is one example of the method for producing the wrap film of this embodiment, and the method may be carried out using various apparatus configurations and conditions other than those described above, and for example, other known methods may be used.

[0071] [Wound body] The wrap film of this embodiment can be used in various forms, for example, as a roll of wrap film. When the wrap film is rolled, it may or may not have a core.

[0072] When it is in the form of being wound around a core, for example, it can be a wrap film wound body including a cylindrical core and the wrap film of the present embodiment wound around the core. A wound body refers to an object having a roll shape by winding a wrap film around a core or the like.

[0073] The rewinding trouble that occurs during the use of a roll-shaped wrap film or the like can be effectively suppressed by the wrap film of the present embodiment. The material, size, etc. of the core are not particularly limited, and a known core such as a paper tube can be used. Further, if the wrap film is in a roll shape, the core may or may not be present. The wrap film wound body of the present embodiment can be stored and used in a cosmetic case having a cutting blade for cutting the wrap film.

Example

[0074] Hereinafter, the present invention will be described more specifically using examples and comparative examples. The present invention is not limited by the following examples at all.

[0075] In the examples and comparative examples, each physical property and each characteristic were measured as follows.

[0076] The TD direction molecular chain orientation of the wrap film was measured as follows. Using a Raman microscope (manufactured by HORIBA, Raman microscope XploRA), Raman spectroscopy of the wrap film was measured. The measurement wavelength used was 532 nm. The measurement conditions were an exposure time of 30 seconds, an integration number of 2 times, a grating of 1800 cm -1 , a dimming filter of 10%, an objective lens magnification of 100 times, a confocal hole of 500, a slit width of 100 μm, and a measurement wavelength of 200 to 3100 cm -1 And it was set. Laser polarization was not used, and Raman polarization was set to "Vertical". In addition, the measurement of the molecular chain orientation in the TD direction was performed as follows as an example. FIG. 3 is a schematic diagram of an example of the sampling position when the wrap film is pulled out. As shown in FIG. 3, a sample (21) in the shape of a square with a side length of 1 cm was obtained with an end face (20) parallel to the flow direction (19) from the wrap film as one side. FIG. 4 is a schematic diagram of an example when the measurement sample (21) is placed on the slide glass (22). As shown in FIG. 4, the obtained sample (21) was fixed on the slide glass (22) for measurement. At this time, two slide glasses were used stacked, and on the upper slide glass, the end face (20) parallel to the flow direction of the sample (21) was placed parallel to the long side (23) of the slide glass. FIG. 5 is a schematic diagram of an example of a Raman microscope image. As shown in FIG. 5, there are a horizontal direction (24) and a vertical direction (25) of the microscope observation image. As shown in FIG. 6, after rotating the upper slide glass so that the end face (20) parallel to the flow direction of the sample (21) is parallel to the vertical direction (25) of the microscope observation image, the measurement was performed. In this measurement, the peak intensity (peak height) of the peak of the spectrum in the wavenumber band of the CCl2-derived peak (630 - 680 cm -1 ) in the MD direction was taken as the A value, and the peak intensity (peak height) of the peak of the spectrum in the wavenumber band of the CH2-derived peak (2840 - 2890 cm -1 ) in the MD direction was calculated as the D value. Each value was measured 10 times in different fields of view of the same sample, and the A value / D value was calculated at each measurement point, and its arithmetic mean was calculated as the molecular chain orientation in the TD direction by the following formula (2). Molecular chain orientation in the TD direction = Peak intensity (A value) of the CCl2-derived peak (630 - 680 cm -1 ) in the MD direction / Peak intensity (D value) of the CH2-derived peak (2840 - 2890 cm -1 ) in the MD direction ··· (2) At this time, the molecular chain orientation in the TD direction represents the orientation of the main chain oriented in the TD direction and is orthogonal to CCl2 in the MD direction.

[0077] <Molecular chain orientation in the MD direction> In this embodiment, the MD molecular chain orientation of the wrap film was measured as follows. The Raman spectroscopy of the wrap film was measured using a Raman microscope (HORIBA, Raman microscope XploRA). The measurement wavelength was 532 nm. The measurement conditions were an exposure time of 30 seconds, an accumulation count of 2, and a grating of 1800 cm. -1 , 10% neutral density filter, 100x objective lens magnification, 500 confocal hole, 100μm slit width, measurement wavelength 200~3100cm -1 Laser polarization was not used, and Raman polarization was set to "Vertical." The measurement of the MD molecular chain orientation was carried out as follows. Figure 3 is a schematic diagram of an example of the sampling position when the wrap film was pulled out. As shown in Figure 3, a square sample (21) with one side being 1 cm long was obtained from the wrap film, with the end face (20) parallel to the flow direction (19) as one side. Fig. 4 is a schematic diagram of an example in which a measurement sample (21) was placed on a glass slide (22). As shown in Fig. 4, the obtained sample (21) was fixed on the glass slide (22) and measured. In this case, two glass slides on which the sample (21) was placed were used in a stack, and the end surface (20) of the sample (21) parallel to the flow direction was placed on the upper glass slide so that it was parallel to the long side (23) of the glass slide. Figure 5 is a schematic diagram of an example of a Raman microscope image. As shown in Figure 5, there is a horizontal direction (24) of the microscope observation image and a vertical direction (25) of the microscope observation image. As shown in Figure 4, the upper slide glass was rotated so that the end face (20) of the sample (21) parallel to the flow direction was parallel to the horizontal direction (24) of the microscope observation image, and then measurement was performed. In this measurement, the peaks due to CCl2 in the TD direction (630-680 cm -1 The C value is the intensity (peak height) of the spectrum peak in the wavenumber band of the TD direction. The peak originating from CH2 (2840-2890 cm -1The peak intensity (peak height) of the spectrum in the wavenumber band was calculated as the B value. Each value was measured at 10 points in different fields of view of the same sample, and the C value / B value was calculated at each measurement point. The arithmetic mean was calculated as the molecular chain orientation in the MD direction by the following formula (2). Molecular chain orientation in the MD direction = Peak of CCl2-derived in the TD direction (630 - 680 cm -1 ) Intensity (C value) / Peak of CH2-derived in the TD direction (2840 - 2890 cm -1 ) Intensity (B value) ··· (3) At this time, the molecular chain orientation in the MD direction represents the orientation of the main chain oriented in the MD direction and is orthogonal to CCl2 in the TD direction.

[0078] <Molecular chain orientation ratio> The molecular chain orientation ratio was calculated by the following formula (1) from the A value and C value obtained by the above measurement method. Molecular chain orientation ratio = Peak of CCl2-derived in the MD direction (630 - 680 cm -1 ) Intensity (A value) / Peak of CCl2-derived in the TD direction (630 - 680 cm -1 ) Intensity (C value) ··· (1).

[0079] <Tensile breaking strength and tensile elongation at break in the TD direction> The tensile breaking strength and tensile breaking elongation of the wrap film in the TD direction were measured in an atmosphere of 23±2°C and 50±10% RH. Test specimens were cut into strips of 150 mm length and 10 mm width in the TD direction. To prevent scratches, the test specimens were cut into strips, and the blades were changed for each test specimen. Using an Autograph AG-IS (Shimadzu Corporation), the test specimens, set to a width of 10 mm and a chuck distance of 100 mm, were pulled vertically at a tensile speed of 300 mm / min, and the load and elongation at break were measured. The elongation at break was taken as the tensile breaking elongation (unit: %) of the wrap film in the TD direction. The obtained load was divided by the cross-sectional area of ​​the test specimen to calculate the tensile breaking strength (unit: MPa) of the wrap film in the TD direction. During measurement, the wrap film was attached to the gripper so that the TD direction of the wrap film coincided with the pulling direction of the testing machine. The chuck positions were determined by making marks 25 mm from both ends in the longitudinal direction using a material that will not damage the test material (such as red ink). The test specimens were visually inspected with a straight ruler and using a microscope to ensure that there were no scratches or holes on the surface or edges. Test specimens that did not meet these conditions were discarded. The test specimens were clamped evenly and firmly with the gripping tools to prevent slippage and to prevent the gripping parts from shifting during the test. In addition, the arithmetic mean of the three results, excluding the highest and lowest values ​​out of the five measurements, was calculated and rounded to two significant digits.

[0080] <Easy to grip the cut surface when a break occurs> When cutting a wrap film with a saw blade, if the film is not cut cleanly and tears halfway through, a sensory evaluation was performed to assess the ease of gripping the protruding cut edge that occurs when the wrap film is not cut cleanly with the saw blade. The sensory evaluation of the ease of gripping the protruding cut edge that occurs when the film is not cut cleanly was performed using the following method. That is, 10 experienced evaluators (including men and women) manually pulled out a wrap film stored in a commercially available wrap film gift box (a gift box of Saran Wrap (registered trademark), manufactured by Asahi Kasei Home Products Corporation, 22 cm x 50 m) and cut it with a saw blade, and then evaluated the ease of gripping the protruding cut edge on a scale of 1 to 10 (10 being the easiest to grip and 1 being the hardest to grip). The ease of gripping the protruding cut edge of the wrap film was evaluated based on the average scores of 10 evaluators and according to the following evaluation criteria. If the rating for ease of gripping is "A", the wrap film has exceptional ease of gripping, and can be said to have the best ease of gripping. If the rating is "B", the wrap film has very pleasant ease of gripping. If the rating is "C", the wrap film can be said to have pleasant ease of gripping. If the rating is "D", the wrap film has good ease of gripping. If the rating is "E", there is no particular problem with the ease of gripping the wrap film. If the rating is "X", the wrap film has poor ease of gripping. [Evaluation criteria] A: 8.0 points or more B: 6.0 points or more and less than 8.0 points C: 4.0 points or more and less than 6.0 points D: 2.0 points or more and less than 4.0 points E: 1.0 or more and less than 2.0 points ×: Less than 1.0 points

[0081] <Ease of recycling wrap film> The wrap film was cut with a saw blade, used, and then evaluated by repeatedly wrapping a plate with the wrap film, assuming the action of using the wrap film again. The evaluation of the action of repeatedly wrapping a plate with the wrap film was carried out using the following method. That is, 10 experienced evaluators (including men and women) manually pulled out the wrap film stored in a commercially available wrap film gift box (a gift box of Saran Wrap (registered trademark), manufactured by Asahi Kasei Home Products, 22 cm x 50 m) and cut it with a saw blade, then wrapped a porcelain bowl with a diameter of 145 mm as a container with the wrap film. The wrapped wrap film was left to stand for 10 seconds. The wrap film was then peeled off and checked for any breakage. The evaluation was carried out in an atmosphere of 23 ± 2 ° C and 50 ± 10% RH. The series of actions of wrapping and peeling was recorded as one action, and the number of actions at the time of breakage was recorded. The ease of reusing the wrap film was evaluated based on the average score of the number of operations until breakage occurred by 10 evaluators, according to the following evaluation criteria. If the reusability rating is "A", the wrap film has exceptionally good reusability, and can be said to have the best reusability. If the rating is "B", the wrap film can be said to be very good reusability. If the rating is "C", the wrap film can be said to have excellent reusability. If the rating is "D", the wrap film can be said to have good reusability. If the rating is "E", there are no particular problems with reusability. If the rating is "X", the wrap film has poor reusability. [Evaluation criteria] A: 8.0 or more times B: 6.0 times or more but less than 8.0 times C: 4.0 or more times but less than 6.0 times D: 2.0 times or more but less than 4.0 times E: 1.0 or more times but less than 2.0 times ×: Less than 1.0 times

[0082] Example 1 A composition was obtained by mixing 93.4 mass% of a polyvinylidene chloride resin with a weight-average molecular weight of 120,000 (vinylidene chloride monomer content: 85 mass%; vinyl chloride monomer content: 15 mass%), 5.5 mass% of acetyl tributyl citrate (hereinafter also referred to as "ATBC", manufactured by Taoka Chemical Co., Ltd.), and 1.1 mass% of epoxidized soybean oil (hereinafter also referred to as "ESO", trade name "Newcizer 510R", manufactured by Nippon Oil & Fats Corporation). The resulting composition was fed to a melt extruder, melted, and extruded through an annular die attached to the tip of the extruder to form a sock. The heating conditions of the extruder were adjusted so that the molten resin temperature at the slit outlet of the annular die was 185°C, and the composition was extruded into a ring shape. After cooling in a sock solution and cooling bath, the parison was opened to form a bubble, and double bubble inflation stretching was performed under the stretching conditions shown in Table 1. At this time, the 3rd / 2nd stretch ratio was 3.7 times, and the TD direction was stretched 5.5 times to form a tubular film (bubble). Here, the cooling bath temperature was 23°C, the stretching temperature was 42°C, and the difference between the cooling bath temperature and the stretching temperature (stretching temperature - cooling bath temperature) was 19°C. The obtained cylindrical film was nipped and folded flat, and then the two-ply film was wound up. This film was slit to a width of 300 mm and rewound onto a paper tube while peeling it into a single film. 50 m of the film was then wound onto a 307 mm long paper tube, yielding a roll of wrap film (thickness: 10 μm). This was used to perform the various evaluations using the methods described above. The evaluation results are shown in Table 1.

[0083] <Examples 2 to 11 and Comparative Examples 1 to 10> A wrap film roll was produced in the same manner as in Example 1, except that the raw materials, additives, stretching conditions, etc. were changed as shown in Tables 1 and 2, and the evaluations were carried out using the methods described above. The evaluation results are shown in Tables 1 and 2.

[0084] [Table 1]

[0085] [Table 2]

[0086] Comparing Examples 1 to 11 with Comparative Examples 1 to 10, it was found that by controlling the molecular chain orientation ratio calculated by formula (1) within a specific range, if the wrap film is torn while being pulled out from the gift box, the cut edge becomes easier to grip and recover, and the film becomes easier to reuse when used repeatedly.

[0087] Furthermore, when comparing Examples 1 to 11, it was found that the greater the orientation of the molecular chains in the TD direction, the easier it was to grip the cut surface when a break occurred, and the easier it was to reuse after repeated use. [Explanation of symbols]

[0088] 1...Extruder, 2...Die, 3...Die opening, 4...Sock, 5...Sock liquid, 6...Cooling tank, 7...First pinch roll, 8...Parison, 9...Second pinch roll, 10...Bubble, 11...Third pinch roll, 12...Double ply film, 13...Winding roll, 14...Decorative box, 15...Film cutting blade, 16...Wound body, 17...Wrap film, 18...Cut edge, 19...Flow direction of wrap film, 20...Edge parallel to the flow direction of wrap film, 21...Square sample with a side length of 1 cm, 22...Glass slide, 23...Long side of glass slide, 24...Horizontal direction of the microscope observation image, 25...Vertical direction of the microscope observation image

Claims

1. Contains polyvinylidene chloride resin, A wrap film having a molecular chain orientation ratio calculated by the following formula (1) in polarized Raman measurement of 0.3 to 3.0; Molecular chain orientation ratio = CCl in MD 2 The peak derived from (630-680 cm -1 ) Intensity (A value) / CCl in TD direction 2 The peak derived from (630-680 cm -1 ) Strength (C value)...(1).

2. Methylene group (CH 2 ) The wrap film according to claim 1, wherein the molecular chain orientation in the TD direction calculated by the following formula (2) when measuring polarized Raman spectroscopy in the TD direction is 2.0 to 5.8: Molecular chain orientation in TD direction = CCl in MD direction 2 Peak derived from (630-680 cm -1 ) Strength (A value) / CH in MD direction 2 Peak derived from (2840-2890 cm -1 ) Strength (D value)...(2).

3. The wrap film according to claim 1 or 2, having a tensile breaking strength in the TD direction of 100 MPa or more.

4. The wrap film according to claim 1 or 2, having a tensile elongation at break in the TD direction of 100% or less.

5. The wrap film according to claim 1 or 2, having a thickness of 6 to 18 μm.

6. A roll in which the wrap film according to claim 1 or 2 is wound around a core.

Images