plastic wrap

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 wound body using the same.

Background Art

[0002] Conventionally, wrap films have been widely used in many households as wrap films for foods, etc., because they are excellent in characteristics such as adhesion between films and to adherents, gas barrier properties against gases such as water vapor and oxygen, and cutability when used in a cosmetic case. Household wrap films are mainly used for storing foods in refrigerators or freezers, and for overlapping and using when heating foods contained in containers in a microwave oven.

[0003] As such a wrap film, for example, Patent Document 1 discloses a wrap film containing a polyvinylidene chloride-based resin, represented by 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, 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 obtained by the following formula (1a): 0.0003 ≦ Δn ≦ 0.0013 (1a) satisfies the condition represented by the following formula (2): represented 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, 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 film thickness direction) The plane orientation ΔP obtained by this method is given by the following equation (2a): -0.0120 ≤ ΔP ≤ -0.0102 (2a) A wrap film is disclosed that satisfies the conditions represented by [the formula shown]. Furthermore, for example, Patent Document 2 discloses a wrap film having a tensile strength of 100 MPa or more in the direction perpendicular to the flow direction (TD), a tensile elongation of 100% or less, a tensile modulus of elasticity of 280 MPa or more, and a tensile modulus of elasticity of 380 MPa or more in the flow direction (MD). [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] International Publication No. 2016-189987 [Patent Document 2] Japanese Patent Publication No. 2019-43679 [Overview of the project] [Problems that the invention aims to solve]

[0005] However, as shown in Figure 2, for example, when pulling the wrap film 17 out of the cosmetic box 14, or when pulling the film out of the cosmetic box 14 and cutting it, the film may not be cut cleanly and may tear midway, not being cut perpendicular to the direction of film pulling (MD direction), resulting in a portion of the cut end 18 sticking out. If the protruding cut end 18 is pinched to resolve this, the film is prone to deforming in the TD direction (perpendicular to the MD direction), and if the breaking strength is low, the pinched film may tear again, making it difficult to repair. Furthermore, if the film's breaking strength decreases, it may tear when attempting to reuse the wrap film, making it difficult to recycle. The wrap films described in Patent Documents 1 and 2 do not address these issues and have room for improvement.

[0006] Therefore, an object of the present invention is to provide a wrap film that is easy to grip and restore the cut end surface, easy to reuse, when the film breaks during pulling out from a cosmetic case. Means for Solving the Problems

[0007] As a result of intensive studies to overcome these problems, the inventors have found that a wrap film containing a polyvinylidene chloride-based resin and having a molecular chain orientation ratio satisfying a predetermined condition has a cut end surface of the wrap film that is easy to grip and is difficult to tear even when the cut end surface is gripped, so that it is easy to eliminate (restore) the state where the wrap film is torn in the middle, and is difficult to break even when repeatedly used, so that it is easy to reuse, and have completed the present invention.

[0008] That is, the present invention is as follows. [1] A wrap film containing a polyvinylidene chloride-based resin, where the molecular chain orientation ratio calculated by the following formula (1) when measuring polarized Raman is 0.3 to 3.0; Molecular chain orientation ratio = Intensity (A value) of the peak derived from CCl2 in the MD direction (630 to 680 cm -1 ) / Intensity (C value) of the peak derived from CCl2 in the TD direction (630 to 680 cm -1 ) ··· (1). [2] Further containing a compound containing a methylene group (CH2), The wrap film according to [1], wherein the molecular chain orientation in the TD direction calculated by the following formula (二) when measuring polarized Raman in the TD direction is 2.0 to 5.8; Molecular chain orientation in the TD direction = Intensity (A value) of the peak derived from CCl2 in the MD direction (630 to 680 cm -1 ) / Intensity (D value) of the peak derived from CH2 in the MD direction (2840 to 2890 cm -1 ) ··· (2). [3] The wrap film according to [1] or [2], wherein the tensile breaking strength in the TD direction is 100 MPa or more. [4] A wrap film according to any of [1] to [3], wherein the tensile break elongation in the TD direction is 100% or less. [5] A wrap film having a thickness of 6 to 18 μm, as described in any of [1] to [4]. [6] A rolled body in which the wrap film described in any of [1] to [5] is wound onto a core. [Effects of the Invention]

[0009] The present invention provides a wrap film that, when pulled out of a cosmetic box, has a cut end that is easy to grasp and repair, and is also easy to reuse. [Brief explanation of the drawing]

[0010] [Figure 1] This is a schematic diagram of an example of the manufacturing process for the wrap film of the present invention. [Figure 2] This is a schematic diagram of an example of a wrap film container that holds wrap film. [Figure 3] This is a schematic diagram showing an example of a sampling position when the plastic wrap is pulled out. [Figure 4] This is a schematic diagram of an example of how a measurement sample is placed on a glass slide. [Figure 5] This is a schematic diagram of an example of a Raman microscope image. [Figure 6] This is a schematic diagram illustrating an example of a measurement sample being placed on a glass slide and rotated. [Modes for carrying out the invention]

[0011] The embodiments for carrying out the present invention (hereinafter referred to as "this embodiment") will be described in detail below. However, the present invention is not limited to the following embodiments and can be implemented in various ways within the scope of its gist.

[0012] The wrap film of this embodiment contains a polyvinylidene chloride resin, and the molecular chain orientation ratio calculated by the following formula (1) when polarized Raman light is measured is 0.3 to 3.0. Molecular chain orientation ratio = peak originating from CCl2 in the MD direction (630-680 cm) -1 ) Intensity (A value) / Peak originating from CCl2 in the TD direction (630~680cm) -1 ) Intensity (C value) ... (1) The wrap film of this embodiment has these features, so if the film tears midway when pulled out of the cosmetic box, the cut end is easy to grasp and repair, and it is easy to reuse when used repeatedly. In this embodiment, the orientation of each molecular chain 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-based resin. The polyvinylidene chloride resin used in this embodiment is not particularly limited as long as it contains constituent units derived from vinylidene chloride. In addition to constituent units derived from vinylidene chloride, one or more monomers copolymerizable with vinylidene chloride may be copolymerized, 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; vinyl acetate, etc.

[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. A weight-average molecular weight (Mw) within this range tends to improve the mechanical strength of the wrap film. A polyvinylidene chloride resin with a weight-average molecular weight within this range can be obtained, for example, by controlling the mixing ratio of polyvinylidene 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 using a standard polystyrene calibration curve by gel permeation chromatography (GPC).

[0015] When the polyvinylidene chloride resin is a copolymer resin, the ratio of constituent units derived from vinylidene chloride is not particularly limited, but it is preferable that it contains 72 to 93% by mass of constituent units derived from vinylidene chloride, and more preferably 81 to 90% by mass. When the constituent units derived from vinylidene chloride are 72% by mass or more, the glass transition temperature of the polyvinylidene chloride resin is low and the film becomes softer, which tends to reduce film tearing even when used in low-temperature environments such as winter. On the other hand, when the constituent units derived from vinylidene chloride are 93% by mass or less, it tends to suppress a significant increase in crystallinity and suppress deterioration of moldability when the film is stretched. In particular, wrap films made of polyvinylidene chloride resin containing 72% by mass or more of vinylidene chloride-derived structural units are prone to physical deterioration when stored and distributed under high temperatures such as in summer, as microcrystals form and grow due to the heat, resulting in a tendency for tearing problems to occur when the film is used. Therefore, the effects of the present invention are even more pronounced.

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

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

[0018] The mole fractions of the constituent units are determined from the spectral area values ​​(areas of the signals in the NMR spectrum) of these signals. The mole fractions are expressed as follows: • Mole fraction of A (mol%): P(A) • Mole fraction of B (mol%): P(B)

[0019] Based on the area values ​​(peak areas in the NMR spectrum) of signals 1, 2, and 3 assigned as described above, the integral values ​​of the signals on the spectrum are assigned as follows. The integral of signal 1 (approximately 5.2-4.5 ppm) is equivalent to one 1H of B. • The integral of signal 2 (approximately 4.2-3.8 ppm) is divided into 1H2 units of A. • The integral of signal 3 (approximately 3.5-2.8 ppm) is divided into 1H4 units of A.

[0020] The following equation is used to calculate each mole fraction. P(A) + P(B) = 100

[0021] P(A) and P(B) are calculated using the following formulas. P(B):P(A) = Integral value of signal 1 : (Integral value of signal 2 + Integral value of signal 3 / 2) / 2 P(A) = 100 - P(B)

[0022] The molecular weight of A, a constituent unit derived from vinylidene chloride (-CH2-CCl2-), was set to 97.0, and the molecular weight of B, a constituent unit derived from vinyl chloride (-CH2-CHCl-), was set to 62.5. The following equation was used to calculate each mass fraction. The mass fractions are 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 polyvinylidene chloride resin content is preferably 77 to 94% by mass, and more preferably 85 to 94% by mass, relative to the total amount of the wrap film. By keeping the polyvinylidene chloride resin content within this range, the tendency for the film to stretch due to plasticizing effects from additives is suppressed, resulting in improved cutability of the film.

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

[0025] The wrap film of this embodiment may contain various additives in addition to the polyvinylidene chloride resin, as needed. 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] <Epoxy vegetable oil> In this embodiment, the wrap film preferably contains epoxidized vegetable oil from the viewpoint of suppressing changes in the color tone of the wrap film. The epoxidized vegetable oil also acts as a stabilizer for vinylidene chloride resin extrusion processing.

[0027] Epoxy-modified vegetable oils are not particularly limited, but generally include those produced by epoxidizing edible oils and fats. Specifically, although not particularly limited, examples include epoxy-modified soybean oil (ESO) and epoxy-modified linseed oil. Among these, ESO is preferred because it tends to suppress deterioration of the film's pullability from the packaging box when the wrap film is stored at high temperatures.

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

[0029] The NMR-based measurement method for the epoxidized vegetable oil content follows the procedure described below. Weigh out 50 mg of the sample, dissolve it in a deuterated solvent (solvent: deuterated THF, internal standard: dimethyl terephthalate, volume: 0.7 ml), and measure it using 400 MHz proton NMR (number of integrations: 512 times). The ratio of the integral value at 2.23 to 2.33 ppm to the integral value at 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] Furthermore, the method for measuring the epoxidized vegetable oil content using gel permeation chromatography follows the procedure described below. Weigh 3g of the sample into a tall beaker, add 30ml of THF, stir with a stirrer, and heat (50°C x 4min) until completely dissolved. While stirring with a stirrer, slowly add methanol (170 ml) dropwise to re-settle the mixture. Once all methanol has been added, filter the mixture by suction into a glass filter. Concentrate the filtrate, vacuum dry it, and then add it to a 10 ml volumetric flask and make up with chloroform. Filter the chloroform solution through a syringe filter (PTFE material, pore size 0.45 μm) and perform GPC analysis. Prepare three levels of standard samples by weighing ESO into a volumetric flask and making up with chloroform. Filter these samples through a syringe filter in the same way as the samples and perform GPC analysis. Create a calibration curve by plotting the GPC analysis results against the standard sample concentrations. The GPC area of ​​the sample is applied to the calibration curve, the concentration is calculated, and the ESO quantitative value is calculated.

[0031] <Citrate esters and dibasic acid esters> From the viewpoint of moldability and other factors, 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, triethyl acetyl citrate, tributyl acetyl citrate (hereinafter also referred to as "ATBC"), and tri-n-(2-ethylhexyl) acetyl citrate. Among these, ATBC is preferred because it has a high plasticizing effect on vinylidene chloride resins, and even in small amounts it sufficiently plasticizes the resin and tends to 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 azelaic acid and octyl azelaic acid; and sebacate acid esters such as dibutyl sebacate (hereinafter also referred to as "DBS") and di-2-ethylhexyl sebacate. Among these, DBS is preferred because it has a high plasticizing effect on polyvinylidene chloride resins, and even in small amounts it sufficiently plasticizes the resin and tends to improve moldability.

[0034] The total content of the citrate ester and dibasic acid ester is not particularly limited, but from the viewpoint of providing better moldability and preventing excessive adhesion of the wrap film when the additive content is high, it is preferably 3.0 to 8.0% by mass, more preferably 3.0 to 7.0% by mass, even more preferably 3.0 to 5.5% by mass, and particularly preferably 3.5 to 5.5% by 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 easier for rearrangement such as the formation and growth of microcrystals to occur. Furthermore, when exposed to high temperatures, it becomes more susceptible to physical degradation, and the film becomes more stretchable, making it difficult for the cutting blade to bite into the film, thus reducing its cutting performance. Therefore, the effects of the present invention become even more pronounced.

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

[0037] The above-mentioned acetylated fatty acid glycerides may be acetylated monoglycerides, acetylated diglycerides, or acetylated triglycerides of fatty acids. For example, the above-mentioned acetylated laurate glycerides include acetylated monoglycerides of lauric acid, acetylated diglycerides of lauric acid (DALG: diacetyllauroylglycerol), and acetylated triglycerides of lauric acid. Among these, acetylated laurate glycerides are preferred, and acetylated diglycerides of lauric acid are more preferred.

[0038] The content of 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 6.0% by mass, relative to the total amount of the wrap film. When the content of acetylated fatty acid glycerides is within the above range, the moldability tends to improve. Note that the method for measuring the content of each component from the wrap film varies depending on the analyte. The content of acetylated fatty acid glycerides can be obtained by extracting the additive from the wrap film using an organic solvent such as acetone and then performing gas chromatography analysis.

[0039] The total content of at least one compound selected from the group consisting of citrate 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 the wrap film. When the total content of citrate esters, dibasic acid esters, and acetylated fatty acid glycerides is within the above range, the moldability is further improved, and excessive stickiness due to bleeding of the wrap film when it contains a high amount of epoxidized vegetable oil tends to be suppressed.

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

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

[0042] The aforementioned stabilizers are not particularly limited, but specifically 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, myristicate, palmitate, stearate, isostearate, oleate, ricinolate, 2-ethylhexylate, isodecanate, neodecanoate, and calcium benzoate.

[0043] The weather-resistant improving agent is not particularly limited, but specifically, examples include ultraviolet absorbers such as ethylene-2-cyano-3,3'-diphenyl acrylate, 2-(2'-hydroxy-5'-methylphenyl)benzolytriazole, 2-(2'-hydroxy-3'-t-butyl-5'-methylphenyl)5-chlorobenzotriazole, 2-hydroxy-4-methoxybenzophenone, and 2,2'-dihydroxy-4-methoxybenzophenone.

[0044] The aforementioned colorants such as dyes or pigments are 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 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 aforementioned antibacterial agent is not particularly limited, but specific examples include silver-based inorganic antibacterial agents.

[0047] The lubricant is not particularly limited, but specifically includes fatty acid hydrocarbon lubricants such as ethylene bissteramide, butyl stearate, polyethylene wax, paraffin wax, carnauba wax, myristyl myristate, and stearyl stearate, as well as 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 phosphate ester metal salts.

[0049] The content of the other additives mentioned above 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, relative to 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 known additives containing a methylene group (CH2), such as plasticizers, stabilizers, weather-resistant agents, colorants such as dyes or pigments, antifogging agents, antibacterial agents, lubricants, and nucleating agents used in food packaging materials, as mentioned above.

[0051] The total content of compounds containing a methylene group (CH2) 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 the wrap film.

[0052] The wrap film of this embodiment contains a polyvinylidene chloride resin, and the molecular chain orientation ratio calculated by the following formula (1) when polarized Raman light is measured is 0.3 to 3.0. Molecular chain orientation ratio = peak originating from CCl2 in the MD direction (630-680 cm) -1 ) Intensity (A value) / Peak originating from CCl2 in the TD direction (630~680cm) -1 ) Intensity (C value) ... (1). In this embodiment, the wrap film has a molecular chain orientation ratio of 0.3 or higher, which causes the molecular chains to be oriented in the TD direction, making it difficult to stretch in the TD direction and increasing the breaking stress. Therefore, if a break occurs midway, the cut end is easy to grasp. Furthermore, by setting the molecular chain orientation ratio of the wrap film in this embodiment to 3.0 or less, the tear strength in the TD direction is sufficient, making the wrap film less prone to tearing. From a similar 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 in which the molecular chain orientation ratio falls within the above range. For example, in the method for manufacturing a wrap film described later, one method is to adjust the difference between the cooling tank temperature and the stretching temperature (stretching temperature - cooling tank temperature) to a specific range (for example, 19°C to 37°C).

[0053] The wrap film of this embodiment further contains a compound containing a methylene group (CH2), and preferably the molecular chain orientation in the TD direction, calculated by the following formula (2) when polarized Raman light in the TD direction is measured, is 2.0 to 5.8. Molecular chain orientation in the TD direction = peak originating from CCl2 in the MD direction (630-680 cm) -1 ) Intensity (A value) / Peak originating from CH2 in the MD direction (2840~2890cm) -1 ) Intensity (D value) ... (2). In this embodiment, the wrap film has a molecular chain orientation in the TD direction of 2.0 or higher, causing the molecular chains to be oriented in the TD direction. This makes it less likely to stretch in the TD direction and increases the breaking stress, making it easier to grasp the cut end when it breaks. Furthermore, because of the increased breaking stress, it is less likely to break even when used repeatedly, making it easy to reuse. Furthermore, by setting the molecular chain orientation in the TD direction of the wrap film in this embodiment to 5.8 or less, the tensile breaking strength in the TD direction is sufficient, making the wrap film less prone to tearing. From a similar viewpoint, the molecular chain orientation in the TD direction calculated by formula (2) above is more preferably 2.3 to 5.8, 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 in 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 in this embodiment is within the above range, problems with film tearing are suppressed, cutability is further improved, adhesion is further improved, and it tends to be easier to reuse.

[0055] In this embodiment, the wrap film preferably has a tensile breaking strength X1 (MPa) in the TD direction of 100 or more, and preferably in the range of 100 ≤ X1 ≤ 300. When the tensile breaking strength in the TD direction of this embodiment is in the range of 100 MPa or more, the strength to break along the direction perpendicular to the TD direction when cut is sufficient, and in the case of rolled wrap for food packaging, vertical tearing problems when cut are suppressed, and it tends to be easier to reuse even when used repeatedly. Furthermore, when the tensile breaking strength in the TD direction of this embodiment is in the range of 300 MPa or less, the strength to break along the direction perpendicular to the TD direction when cut is not too high, and in the case of rolled wrap for food packaging, vertical tearing problems when cut tend to be suppressed. From the perspective of practical use, it is even more preferable to have a range of 130 ≤ X1 ≤ 300, even more preferably 150 ≤ X1 ≤ 300, even more preferably 180 ≤ X1 ≤ 300, and particularly preferably 190 ≤ X1 ≤ 300. There are no particular limitations on the method for controlling the tensile breaking strength in the TD direction to the above range, but for example, as described later, one method is to increase the difference between the temperature when the sock extruded from the die is cooled and the temperature when it is stretched in the subsequent process in the method for manufacturing the wrap film. In this case, the temperature of the cooling tank (cooling tank temperature) is preferably 5°C to 23°C, and the temperature of the stretching process (stretching temperature) is preferably 35°C to 42°C. Here, the stretching temperature is the resin temperature of the bubble (10). The difference between the cooling tank temperature and the stretching temperature (stretching temperature - cooling tank 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 tank temperature and the stretching temperature is within the above range, the tensile breaking strength in the TD direction of the wrap film of this embodiment tends to be controlled to the above range. In this embodiment, the tensile breaking strength in the TD direction can be measured by the method described in the later embodiment.

[0056] Furthermore, the wrap film of this embodiment preferably has a tensile elongation at break X2 (%) in the TD direction of 100 or less, and more preferably 15 ≤ X2 ≤ 100. When the tensile elongation at break in the TD direction of the wrap film of this embodiment is in the range of 100% or less, the film is easy to cut, and in the case of rolled wrap for food packaging, vertical tearing problems tend to be suppressed when cut. Also, when the tensile elongation at break in the TD direction of the wrap film of this embodiment is in the range of 15% or more, the film stretches appropriately when cut, making it easy to cut, and in the case of rolled wrap for food packaging, vertical tearing problems tend to be suppressed when cut. From the perspective of practical use, it is even more preferable that it is 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 tensile elongation at break in the TD direction to the above range, but for example, as described later, one method is to increase the difference between the temperature when the sock extruded from the die is cooled and the temperature when it is stretched in the subsequent process in the method for manufacturing the wrap film. In this case, the temperature of the cooling tank (cooling tank temperature) is preferably 5°C to 23°C, and the temperature of the stretching process (stretching temperature) is preferably 35°C to 42°C. The difference between the cooling tank temperature and the stretching temperature (stretching temperature - cooling tank 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 tank temperature and the stretching temperature is within the above range, the tensile elongation at break in the TD direction of the wrap film of this embodiment tends to be controlled to the above range. In this embodiment, the tensile elongation at break in the TD direction can be measured by the method described in the later embodiment.

[0057] <How to manufacture plastic wrap> Next, an example of a method for manufacturing the wrap film of this embodiment will be described. The method for manufacturing the wrap film containing polyvinylidene chloride resin can be any of various methods as long as the molecular chain orientation in the TD direction described above can be satisfied, and is not particularly limited, but usually, for example, the inflation film forming method is used. 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 the composition containing the polyvinylidene chloride resin described above in at least the MD direction and then performing inflation molding. In the inflation film forming method, although not particularly limited, for example, after melt-extruding the polyvinylidene chloride resin composition into a tubular shape from a circular die, the outside of the tubular resin is brought into contact with a refrigerant such as cold water filled in a storage tank called a cooling tank. At that time, 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 brought into contact with the refrigerant such as mineral oil to solidify and form a film. In this specification, the cylindrical resin portion (extruded product) sandwiched between the die opening and the pinch roll is referred to as a "sock." The refrigerant (liquid) injected into the sock is referred to as the "sock liquid." The sock is folded by the pinch roll and the like to form a tubular double-ply film, which is referred to as a "parison."

[0058] The following describes in more detail an example of the inflation film manufacturing method. Figure 1 is a conceptual diagram of an example of the method for manufacturing a wrap film according to this embodiment.

[0059] First, in the extrusion process, a composition containing molten polyvinylidene chloride resin is extruded by an extruder (1) through the die opening (3) of a circular die (2) into a tubular shape, forming a sock (a tubular composition containing polyvinylidene chloride resin) (4).

[0060] Next, in the cooling and solidification process, the outside of the extruded sock (4) is brought into contact with cold water in a cooling tank (6), and sock liquid (5) is injected into the inside of the sock (4) by a conventional method and stored therein, thereby cooling and solidifying the sock (4) from both the inside and outside. At this time, the sock (4) is coated with sock liquid (5) on its inside. The solidified sock (4) is folded by the first pinch roll (7) to form a parison (8), which is a double-ply sheet. 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 for example, water, mineral oil, alcohols, polyhydric alcohols such as propylene glycol and glycerin, and aqueous solutions of cellulose or polyvinyl alcohol can be used. These may be used individually or in combination of two or more. In addition, the sock liquid may contain the weather-resistant improvers, antifogging agents, antibacterial agents, etc., used in food packaging materials, to the extent that they do not impair the effects of this embodiment.

[0062] Next, by injecting air into the inside of the parison (8), the parison (8) is opened again and becomes 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 off by the second pinch roll (9). Then, in the inflation process, air is injected into the tubular parison (8) heated to the appropriate temperature to form bubbles (10) by inflation stretching, and a stretched film is obtained.

[0063] The tear strength of the wrap film in the MD direction can be controlled by the orientation of the polymer chains that make up the wrap film. Rapid cooling of the sock extruded from the die in a cooling tank further suppresses the crystallization of the resin, resulting in an amorphous structure with uniform molecular chains. Subsequently, stretching in the TD direction promotes crystallization oriented in the TD direction.

[0064] In the method for manufacturing the wrap film of this embodiment, it is preferable that the difference between the temperature at which the sock extruded from the die is cooled and the temperature at which it is stretched in the subsequent process is large. In this case, the temperature of the cooling tank (cooling tank temperature) is preferably 5°C to 23°C, and the temperature of the stretching process (stretching temperature) is preferably 35°C to 42°C. The difference between the cooling tank temperature and the stretching temperature (stretching temperature - cooling tank 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 tank 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 controlled within the above range.

[0065] In the method for manufacturing the wrap film of this embodiment, it is preferable to include a step of stretching the unstretched sheet in the flow direction and in a direction perpendicular to the flow direction, and the stretching ratios in the MD direction and TD direction are preferably 4.0 to 6.0 times, and more preferably 4.1 to 5.6 times, independently of each other. In particular, the ratio of the stretching ratio between the second pinch roll (9) and the third pinch roll (11) (hereinafter also referred to as the "3rd / 2nd stretching ratio") to the stretching ratio in the TD direction (hereinafter also referred to as the "TD stretching ratio") makes it possible to control the orientation of the molecular chains in the TD direction. To orient the molecular chains in the TD direction, it is preferable that the TD stretching ratio > 3rd / 2nd stretching ratio.

[0066] The cooling and solidification process is not particularly limited, and known methods can be employed. For example, a method of controlling the cooling tank temperature by changing the temperature of the chilled water used for cooling and solidification 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 tank, thereby further suppressing the progress of resin crystallization and resulting in a uniform amorphous structure of molecular chains. The cooling tank temperature is more preferably 5°C to 23°C. Subsequently, stretching in the TD direction promotes crystallization oriented in the TD direction of molecular chains.

[0067] The method for controlling the stretching ratio is not particularly limited, and known methods can be employed. For example, a method of controlling the stretching temperature by changing the temperature of the hot water used for reheating can be used. Here, the stretching temperature is the resin temperature of the bubble (10). In order to lower the stretching ratio, a lower stretching temperature is preferable because the inflation bubble becomes more stable at a low stretching ratio. In this case, from the viewpoint of the stability of the inflation bubble, it is preferable that the stretching temperature is higher than the stretching room temperature. 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 point midway in the MD direction between the point where stretching is completed in the MD direction and the point where winding begins in the TD direction.

[0068] Subsequently, the stretched film is folded on a third pinch roll (11) to form a double-ply film (12). The double-ply film (12) is wound on a winding roll (13). Furthermore, this film is slit and peeled apart to form a single film (single peeling). Finally, this film is wound onto a core such as a paper tube to obtain a paper tube-wound wrap film roll.

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

[0070] The above description is just one example of a method for manufacturing the wrap film of this embodiment. The method may also be carried out using various other apparatus configurations and conditions, for example, other known methods may be employed.

[0071] [Coiled body] The wrap film of this embodiment can be used in various forms, for example, as a roll of wrap film. When it is in the form of a roll of wrap film, 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) as one side from the wrap film. 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, the slide glasses for placing the sample (21) were used in a double - layer manner, 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 lateral direction (24) and a longitudinal 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) becomes parallel to the longitudinal direction (25) of the microscope observation image, the measurement was performed. In this measurement, the peak intensity (peak height) of the peak of the CCl2 - derived spectrum in the wavenumber band of 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 CH2 - derived spectrum in the wavenumber band of 2840 - 2890 cm -1 in the MD direction was calculated as the D value. Each value was measured at 10 points 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-direction molecular chain orientation of the wrap film was measured as follows. Raman spectroscopy of a plastic wrap film was measured using a Raman microscope (HORIBA XploRA). The measurement wavelength used was 532 nm. The measurement conditions were: exposure time 30 seconds, number of integrations 2, grating 1800 cm². -1 10% neutral density filter, 100x objective lens magnification, 500 confocal hole, 100 μm slit width, measurement wavelength 200-3100 cm -1 This was done. Laser polarization was not used, and Raman polarization was designated as "Vertical". Furthermore, the measurement of MD direction molecular chain orientation was performed as follows, as an example. Figure 3 is a schematic diagram of an example of the sampling position when the wrap film is pulled out. As shown in Figure 3, a square sample (21) with a side length of 1 cm was obtained from the wrap film, with the end face (20) parallel to the flow direction (19) as one side. Figure 4 is a schematic diagram of an example of how a measurement sample (21) is placed on a glass slide (22). As shown in Figure 4, the acquired sample (21) was fixed on the glass slide (22) and measured. At this time, two glass slides were used to place the sample (21), and the end face (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, the microscope image has a lateral direction (24) and a vertical direction (25). 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 lateral direction (24) of the microscope image, and then the measurement was performed. In this measurement, the peak originating from CCl2 in the TD direction (630-680 cm) -1 The peak intensity (peak height) of the spectrum in the wavenumber band is the C value, and the peak originating from CH2 in the TD direction (2840~2890 cm) is the peak intensity (peak height). -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 elongation in the TD direction of the wrap film were measured in an atmosphere of 23±2℃ and 50±10%RH. A 150mm long, 10mm wide strip of wrap film was cut in the TD direction to serve as the test specimen. To prevent damage to the specimen, the blade was replaced after each cut. Using an Autograph AG-IS (Shimadzu Corporation), the 10mm wide, 100mm chuck-to-chuck distance test specimen was pulled vertically at a tensile speed of 300mm / min, and the load and elongation at break were measured. The elongation at this time was defined as the tensile breaking elongation in the TD direction of the wrap film (unit: %). The tensile breaking strength in the TD direction of the wrap film (unit: MPa) was calculated by dividing the obtained load by the cross-sectional area of ​​the specimen. During measurement, the wrap film was mounted on the grips so that its TD direction aligned with the tensile direction of the testing machine. The test specimens were marked 25 mm from both ends along their length using a material that is less likely to damage the specimen (such as red ink), and these marks were used to indicate the chuck positions. The specimens were visually inspected using a straight ruler and a microscope to ensure that there was no twisting and that the surface and edges were free of scratches and holes. Specimens that did not meet these conditions were discarded. The specimens were evenly and firmly clamped with gripping devices to prevent slippage and to ensure that the gripping parts did not shift during the test. Furthermore, the arithmetic mean of the three results obtained from five measurements, excluding the highest and lowest values, was calculated and rounded to two significant figures, with the third digit rounded to the nearest tenth.

[0080] <Ease of gripping the cut surface when breakage occurs> This study simulated the action of picking up a protruding cut end of a piece of plastic wrap that tears midway through a cut with a saw blade, and evaluating the ease with which the protruding cut end could be picked up. The sensory evaluation of the ease with which the protruding cut end could be picked up was conducted using the following method: Ten experienced evaluators (both male and female) pulled out a piece of plastic wrap from a commercially available packaging box (Asahi Kasei Home Products Co., Ltd., product name Saran Wrap (registered trademark), packaging box, 22cm x 50m) by hand and cut it with a saw blade. They then evaluated the ease with which the protruding cut end could be picked up on a scale of 1 to 10, in increments of 1 point (10 being the easiest to pick up, and 1 being the most difficult). Based on the average score of 10 evaluators, the ease of gripping the protruding cut edge of the plastic wrap was evaluated according to the following criteria. If the ease of gripping is rated "A", the wrap film is exceptionally easy to grip and can be said to have the best gripping ability. If the rating is "B", the wrap film is very pleasant to grip. If the rating is "C", the wrap film is pleasantly easy to grip. If the rating is "D", the wrap film is good in terms of gripping ability. If the rating is "E", the wrap film is not particularly problematic in terms of gripping ability. If the rating is "×", the wrap film is poor in terms of gripping ability. [Evaluation Criteria] A: 8.0 points or more B: 6.0 points or higher, less than 8.0 points C: 4.0 points or higher, less than 6.0 points D: 2.0 points or higher, less than 4.0 points E: 1.0 points or more, less than 2.0 points ×: Less than 1.0 points

[0081] <Ease of reusing plastic wrap> The evaluation simulated the action of repeatedly wrapping a plate with plastic wrap, simulating the process of cutting the wrap with a saw blade, using it, and then reusing it. The evaluation of the action of repeatedly wrapping a plate with plastic wrap was carried out using the following method: Ten skilled evaluators (including both men and women) pulled out plastic wrap from a commercially available packaging box (Asahi Kasei Home Products Co., Ltd., product name Saran Wrap (registered trademark), packaging box, 22cm x 50m) by hand, cut it with a saw blade, and then wrapped a 145mm diameter porcelain bowl with the plastic wrap. The bowl was left undisturbed for 10 seconds with the wrap still on. After that, the wrap was peeled off and checked for breakage. The evaluation was conducted in an atmosphere of 23±2℃ and 50±10%RH. The above series of wrapping and peeling actions were recorded as one action, and the number of actions at the point in time when breakage occurred was recorded. Based on the average number of actions taken by 10 evaluators before breakage occurred, the reusability of the plastic wrap was evaluated according to the following criteria. If the ease of reuse rating is "A", the wrap film is exceptionally easy to reuse and can be said to be the most easily reused. If the rating is "B", the wrap film is very easy to reuse. If the rating is "C", the wrap film is good in terms of ease of reuse. If the rating is "D", the wrap film is good in terms of ease of reuse. If the rating is "E", there are no particular problems with ease of reuse. If the rating is "×", it is poor in terms of ease of reuse. [Evaluation Criteria] A: 8.0 times or more B: 6.0 times or more but less than 8.0 times C: 4.0 times or more but less than 6.0 times D: 2.0 times or more but less than 4.0 times E: 1.0 times or more but less than 2.0 times ×: Less than 1.0 times

[0082] <Example 1> A composition was obtained by mixing 93.4% by mass of polyvinylidene chloride resin with a weight-average molecular weight of 120,000 (containing 85% by mass of vinylidene chloride monomer and 15% by mass of vinyl chloride monomer), 5.5% by mass of tributyl acetylcitrate (hereinafter also referred to as "ATBC," manufactured by Taoka Chemical Industries, Ltd.), and 1.1% by mass of epoxidized soybean oil (hereinafter also referred to as "ESO," trade name "New Sizer 510R," manufactured by Nippon Oil & Fats Co., Ltd.). The obtained composition was supplied to a melt extruder and melted, and a sock was formed by melt extrusion through an annular die attached to the tip of the extruder. At this time, 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 material was extruded in an annular shape. After cooling with sock solution and a cooling tank, the parison was opened to form bubbles, and double bubble inflation stretching was performed under the stretching conditions shown in Table 1. In this process, the 3rd / 2nd stretching ratio was 3.7 times, and the TD direction was stretched to 5.5 times to form a tubular film (bubble). Here, the cooling tank temperature was 23°C, the stretching temperature was 42°C, and the difference between the cooling tank temperature and the stretching temperature (stretching temperature - cooling tank temperature) was 19°C. The obtained tubular film was nipped and folded flat, and then the two layers of film were wound up. This film was slit to a width of 300 mm, and each layer was peeled off and rewound onto a paper tube. Then, 50 m of this film was wound onto a 307 mm long paper tube to obtain a roll of wrap film (thickness: 10 μm). This was used to perform each evaluation using the method described above. The evaluation results are shown in Table 1.

[0083] <Examples 2-11, Comparative Examples 1-10> Wrap film rolls were prepared in the same manner as in Example 1, except that the raw materials, additives, and each stretching condition were changed as shown in Tables 1 and 2, and each evaluation was performed using the method described above. The evaluation results are shown in Tables 1 and 2.

[0084] [Table 1]

[0085] [Table 2]

[0086] A comparison of Examples 1-11 with Comparative Examples 1-10 revealed that by controlling the molecular chain orientation ratio calculated by formula (1) to a specific range, if the wrap film tears midway when pulled out of the cosmetic box, the cut end becomes easier to grasp and repair, and the film becomes easier to reuse after repeated use.

[0087] Furthermore, comparing Examples 1 to 11, it was found that the greater the orientation of the molecular chains in the TD direction, the easier it becomes to grasp the cut surface when breakage occurs, and the easier it is to reuse when used repeatedly. [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...Cosmetic box, 15...Film cutting blade, 16...Winding body, 17...Wrap film, 18...Cut end face, 19...Flow direction of wrap film, 20...End face parallel to the flow direction of wrap film, 21...Square sample with sides of 1 cm, 22...Slide glass, 23...Long side of slide glass 24...Horizontal direction of the microscopic image, 25...Vertical direction of the microscopic image

Claims

1. Contains polyvinylidene chloride resin, A wrap film in which the molecular chain orientation ratio calculated by the following formula (1) when polarized Raman light is measured is between 0.3 and 3.0; Molecular chain orientation ratio = CCl in the MD direction 2 Peak of origin (630-680 cm) -1 ) Intensity (A value) / CCl in the TD direction 2 Peak of origin (630-680 cm) -1 ) Intensity (C value) ... (1).

2. methylene group (CH 2 The compound further contains ) The wrap film according to claim 1, wherein the molecular chain orientation in the TD direction, calculated by the following formula (2) when polarized Raman light is measured in the TD direction, is 2.0 to 5.8; Molecular chain orientation in the TD direction = CCl from the MD direction 2 Peak (630 - 680 cm -1 ), intensity (A value) / CH in the MD direction 2 Peak (2840 - 2890 cm -1 ), intensity (D value)... (2).

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

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

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

6. A winding body in which the wrap film according to claim 1 or 2 is wound onto a core.

Images