Stretch film

Abstract

To provide a stretch film which prevents breakage when being packaged at 10°C and 35°C.SOLUTION: A stretch film contains a polyvinyl chloride-based resin, an adipic acid-based plasticizer, a vegetable plasticizer, and an antifogging agent, wherein the content of the adipic acid-based plasticizer is 20 to 40 pts.mass with respect to 100 pts.mass of the polyvinyl chloride-based resin, the content of the vegetable plasticizer is 16 to 20 pts.mass with respect to 100 pts.mass of the polyvinyl chloride-based resin, and the content of the antifogging agent is 1 to 5 pts.mass of 100 pts.mass of the polyvinyl chloride-based resin.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a stretch film. [Background technology]

[0002] Stretch films with excellent flexibility have been widely used for packaging fresh foods such as meat, fish, and vegetables. Specifically, stretch films are used for pre-packaging, in which fresh foods are placed in a polystyrene foam container and the stretch film is overlapped around the container to package the fresh foods. Stretch films are films made of resins such as polyvinyl chloride resins, and examples of such stretch films are known, such as those described in Patent Document 1. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-104241 Summary of the Invention [Problem to be solved by the invention]

[0004] Fresh foods are typically packaged at room temperature (20 to 25°C), but packaging may also be performed in a relatively high temperature environment such as 35°C or a relatively low temperature environment such as 10°C. The inventors of the present invention have conducted research and found that even stretch films that can be used for packaging without tearing in a room temperature environment may tear during packaging if the temperature rises or falls by just 10°C above or below room temperature. Stretch films are required to be usable for packaging without tearing even when subjected to such slight temperature changes.

[0005] Therefore, an object of the present invention is to provide a stretch film that is less likely to tear during packaging at 10°C and 35°C. [Means for solving the problem]

[0006] One aspect of the present invention includes the following [1] to [9]. [1] A film containing a polyvinyl chloride resin, an adipic acid plasticizer, a vegetable plasticizer, and an anti-fogging agent, the content of the adipic acid-based plasticizer is 20 to 40 parts by mass relative to 100 parts by mass of the polyvinyl chloride-based resin, the content of the vegetable plasticizer is 16 to 20 parts by mass relative to 100 parts by mass of the polyvinyl chloride resin, A stretch film in which the content of the anti-fogging agent is 1 to 5 parts by mass relative to 100 parts by mass of the polyvinyl chloride resin. [2] The stretch film according to [1], wherein the vegetable plasticizer is epoxidized soybean oil. [3] The stretch film according to [1] or [2], wherein the adipic acid-based plasticizer is diisononyl adipate. [4] A stretch film according to any one of [1] to [3], wherein the ratio of the mass-based content of the vegetable plasticizer to the mass-based content of the adipic acid-based plasticizer is 0.45 to 0.9. [5] The stretch film according to any one of [1] to [4], wherein the antifogging agent is a glycerin-based surfactant. [6] The stretch film according to any one of [1] to [5], further comprising a stabilizer. [7] The stretch film according to any one of [1] to [6], which has a thickness of 8 to 15 μm. [8] Storage modulus at 10°C and 35°C is 5×10 7 ~3×10 8 The stretch film according to any one of [1] to [7], having a film impact strength of 10 to 40 kJ / m at 10°C and 35°C. [9] The stretch film according to any one of [1] to [8], which is used for packaging food. [Effects of the Invention]

[0007] According to the present invention, a stretch film that is less likely to tear during packaging at 10°C and 35°C can be provided. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments of the present invention will be described in detail.

[0009] A stretch film according to one embodiment contains a polyvinyl chloride resin, an adipic acid plasticizer, a vegetable plasticizer, and an antifogging agent, wherein the adipic acid plasticizer is present in an amount of 20 to 40 parts by weight per 100 parts by weight of the polyvinyl chloride resin, the vegetable plasticizer is present in an amount of 16 to 20 parts by weight per 100 parts by weight of the polyvinyl chloride resin, and the antifogging agent is present in an amount of 1 to 5 parts by weight per 100 parts by weight of the polyvinyl chloride resin.

[0010] (Polyvinyl chloride resin) The stretch film contains a polyvinyl chloride resin. The polyvinyl chloride resin may be a vinyl chloride homopolymer (polyvinyl chloride) or a copolymer of vinyl chloride and another monomer copolymerizable with vinyl chloride. The copolymer may be a graft copolymer, a block copolymer, or a random copolymer. Examples of other monomers include olefins such as ethylene, propylene, and polybutene; vinyl esters of saturated acids such as vinyl acetate and vinyl laurate; alkyl esters of unsaturated acids such as methyl acrylate and methyl methacrylate; alkyl vinyl ethers such as lauryl vinyl ether; maleic acid, acrylonitrile, styrene, methylstyrene, and vinylidene fluoride.

[0011] The degree of polymerization of the polyvinyl chloride resin may be 700 to 1700, 1000 to 1500, or 1200 to 1400, from the viewpoint of making the stretch film stronger and less likely to tear.

[0012] When the polyvinyl chloride resin is a copolymer, the content of vinyl chloride units in the copolymer may be 10% by mass or more, 30% by mass or more, or 50% by mass or more based on the total amount of monomer units. The upper limit of the content of vinyl chloride units in the copolymer is not particularly limited, and may be, for example, 100% by mass or less, or 95% by mass or less based on the total amount of monomer units.

[0013] The content of polyvinyl chloride resin may be 50% by mass or more or 60% by mass or more, based on the total amount of the stretch film, from the viewpoint of improving the strength of the stretch film and making it less likely to tear, and may be 80% by mass or less or 70% by mass or less, from the viewpoint of improving the extensibility of the stretch film, preventing the stretch film from becoming too hard, and further suppressing deformation of the container during pre-packaging.

[0014] (adipic acid plasticizer) The stretch film contains an adipic acid plasticizer. The adipic acid plasticizer is an adipic acid ester. The content of the adipic acid plasticizer in the stretch film is 20 to 40 parts by mass per 100 parts by mass of the polyvinyl chloride resin.

[0015] Examples of the adipic acid plasticizer include bis(2-ethylhexyl) adipate, diisononyl adipate, diisodecyl adipate, bis(2-butoxyethyl) adipate, etc. The stretch film may contain one type of adipic acid plasticizer, or may contain two or more types of adipic acid plasticizers.

[0016] The content of the adipic acid-based plasticizer may be 10% by mass or more, 12% by mass or more, or 14% by mass or more, based on the total amount of the stretch film, in order to prevent the storage modulus at 10°C from becoming too large, thereby improving the strength of the stretch film at 10°C and making the stretch film less likely to tear; or may be 34% by mass or less, 32% by mass or less, or 30% by mass or less, in order to increase the storage modulus at 35°C, thereby improving the strength of the stretch film at 35°C and making the stretch film less likely to tear.

[0017] The content of the adipic acid-based plasticizer may be 25 parts by mass or more, 28 parts by mass or more, or 30 parts by mass or more per 100 parts by mass of the polyvinyl chloride resin, in order to prevent the storage modulus at 10°C from becoming too high, thereby improving the strength of the stretch film at 10°C and making the stretch film less likely to tear; or may be 35 parts by mass or less, 32 parts by mass or less, or 30 parts by mass or less, in order to prevent the storage modulus at 35°C from becoming too high, thereby improving the strength of the stretch film at 35°C and making the stretch film less likely to tear.

[0018] (vegetable plasticizer) The stretch film contains a vegetable plasticizer. The vegetable plasticizer is a plasticizer produced from plant-derived raw materials. The vegetable plasticizer content in the stretch film is 16 to 20 parts by mass per 100 parts by mass of the polyvinyl chloride resin.

[0019] Examples of vegetable plasticizers include epoxidized vegetable oils, cardanol, isosorbide esters, and citrates. These may be derived from vegetable raw materials such as soybeans, palm oil, castor oil, citrates, stearic acid, and starch. The vegetable plasticizer may be epoxidized vegetable oil, which has excellent miscibility with other components. The stretch film may contain one type of vegetable plasticizer or two or more types of vegetable plasticizers.

[0020] Examples of epoxidized vegetable oils include epoxidized soybean oil (ESBO), epoxidized linseed oil, epoxidized safflower oil, etc. The vegetable plasticizer may be epoxidized soybean oil from the viewpoint of excellent miscibility with other components.

[0021] The content of the vegetable plasticizer may be 8% by mass or more, 9% by mass or more, or 10% by mass or more, based on the total amount of the stretch film, in order to ensure that the storage modulus at 35°C is sufficiently large, the strength of the stretch film at 35°C is superior, and the stretch film is less likely to tear; or it may be 16% by mass or less, 15% by mass or less, or 14% by mass or less, in order to prevent the storage modulus at 10°C from becoming too large, the strength of the stretch film at 10°C is superior, and the stretch film is less likely to tear.

[0022] The content of the vegetable plasticizer may be 17 parts by mass or more or 18 parts by mass or more per 100 parts by mass of polyvinyl chloride resin, from the viewpoint of sufficiently increasing the storage modulus at 35°C, thereby improving the strength of the stretch film at 35°C and making the stretch film less likely to tear, or may be 20 parts by mass or less or 19 parts by mass or less, from the viewpoint of preventing the storage modulus at 10°C from becoming too large, thereby improving the strength of the stretch film at 10°C and making the stretch film less likely to tear.

[0023] The ratio of the mass-based content of the vegetable plasticizer to the mass-based content of the adipic acid plasticizer may be 0.45 or more, 0.5 or more, 0.55 or more, or 0.6 or more, from the viewpoints of sufficiently increasing the storage modulus at 35°C, improving the strength of the stretch film at 35°C, and making the stretch film more resistant to tearing. This ratio may be 0.9 or less, 0.85 or less, 0.8 or less, 0.75 or less, 0.7 or less, 0.65 or less, or 0.6 or less, from the viewpoints of preventing the storage modulus at 10°C from becoming too large, improving the strength of the stretch film at 10°C, and making the stretch film more resistant to tearing. From these viewpoints, this ratio may be 0.45 to 0.9.

[0024] (Anti-fogging agent) The stretch film contains an anti-fogging agent. The anti-fogging agent may be a surfactant. The content of the anti-fogging agent in the stretch film is 1 to 5 parts by mass per 100 parts by mass of the polyvinyl chloride resin.

[0025] Examples of anti-fogging agents include glycerin-based surfactants. Glycerin-based surfactants are surfactants in which a fatty acid is ester-bonded to a hydroxy group of glycerin. Examples of glycerin-based surfactants include monoglycerin-based surfactants, diglycerin-based surfactants, and polyglycerin-based surfactants. The stretch film may contain one type of anti-fogging agent, or may contain two or more types of anti-fogging agents from the viewpoint of improving the anti-fogging properties of the stretch film and suppressing clouding of the stretch film.

[0026] Examples of monoglycerin surfactants include monoglycerin laurate, monoglycerin myristate, monoglycerin palmitate, monoglycerin stearate, monoglycerin oleate, monoglycerin linoleate, etc. The monoglycerin surfactant may be monoglycerin stearate from the viewpoint of improving the anti-fogging properties of the stretch film and suppressing the clouding of the stretch film.

[0027] Examples of diglycerin-based surfactants include diglycerin laurate, diglycerin myristate, diglycerin palmitate, diglycerin stearate, diglycerin oleate, diglycerin linoleate, etc. The diglycerin-based surfactant may be diglycerin oleate from the viewpoint of improving the anti-fogging properties of the stretch film and suppressing clouding of the stretch film.

[0028] The stretch film may contain a monoglycerin-based surfactant and a diglycerin-based surfactant as anti-fogging agents from the viewpoint of improving the anti-fogging properties of the stretch film and suppressing clouding of the stretch film. When the stretch film contains a monoglycerin-based surfactant and a diglycerin-based surfactant, the mass ratio of the diglycerin-based surfactant to the mass ratio of the monoglycerin-based surfactant may be 1 or more, 1.5 or more, 2 or more, 3 or more, or 4 or more, or may be 10 or less, 8 or less, 6 or less, 5 or less, or 4 or less.

[0029] The content of the anti-fogging agent may be 0.5% by mass or more, 1% by mass or more, or 1.5% by mass or more, based on the total amount of the stretch film, from the viewpoint of making it easier for the stretch film to peel off from the unwinding device when the stretch film is unwound and from the viewpoint of suppressing fogging of the stretch film after packaging, and may be 5% by mass or less, 3.5% by mass or less, or 3% by mass or less, from the viewpoint of making it less likely for wrinkles to occur in the stretch film when the stretch film is unwound.

[0030] The content of the anti-fogging agent may be 1.5 parts by mass or more, 2 parts by mass or more, or 2.5 parts by mass or more per 100 parts by mass of polyvinyl chloride resin, from the viewpoint of making it easier for the stretch film to peel off from the unwinding device when the stretch film is unwound and from the viewpoint of suppressing fogging of the stretch film after packaging, and may be 4.5 parts by mass or less, 4 parts by mass or less, or 3.5 parts by mass or less, from the viewpoint of making it less likely for wrinkles to occur in the stretch film when the stretch film is unwound.

[0031] The ratio of the mass-based content of the antifogging agent to the mass-based content of the adipic acid plasticizer may be 0.03 or more, 0.05 or more, 0.08 or more, or 0.1 or more from the viewpoints of easily peeling the stretch film from the unwinding device when the stretch film is unwound and suppressing fogging of the stretch film after packaging. The ratio may be 0.2 or less, 0.17 or less, 0.15 or less, 0.13 or less, 0.11 or less, or 0.1 or less from the viewpoint of preventing wrinkles from forming in the stretch film when the stretch film is unwound.

[0032] The ratio of the mass-based content of the anti-fog agent to the mass-based content of the vegetable plasticizer may be 0.05 or more, 0.08 or more, 0.1 or more, 0.15 or more, or 0.17 or more from the viewpoints of easily peeling the stretch film from the unwinding device when the stretch film is unwound and suppressing fogging of the stretch film after packaging. The ratio may be 0.3 or less, 0.28 or less, 0.25 or less, 0.22 or less, 0.2 or less, or 0.17 or less from the viewpoint of preventing wrinkles from forming in the stretch film when the stretch film is unwound.

[0033] In addition to the above components, the stretch film may further contain other components such as resins other than polyvinyl chloride resins, stabilizers, lubricants, fillers, anti-plateout agents, antioxidants, release agents, viscosity reducers, colorants, fluorescent agents, surface treatment agents, crosslinking agents, processing aids, adhesives, antistatic agents, UV absorbers, and antiblocking agents.

[0034] Examples of stabilizers include calcium salts of 2-ethylhexyl acid, citric acid, gluconic acid, sorbic acid, benzoic acid, isodecanoic acid, neodecanoic acid, etc.; zinc salts of 2-ethylhexyl acid, higher fatty acids, isodecanoic acid, neodecanoic acid, etc.; Ca-Zn salts of 2-ethylhexyl acid, higher fatty acids, isodecanoic acid, neodecanoic acid, etc. (e.g., Ca-Zn higher fatty acids). The stretch film may contain one type of stabilizer or two or more types of stabilizers.

[0035] When a stretch film contains a phosphorus compound as a stabilizer, the phosphorus compound may be contained in an amount of 2% by mass or less, preferably 1% by mass or less, based on the total amount of the stretch film, in order to prevent discoloration of food when the stretch film is used for packaging food. Examples of phosphorus compounds include trisnonylphenyl phosphite, triphenyl phosphite, diphenyldecyl phosphite, tridecyl phosphite, tris(2-ethylhexyl) phosphite, tristearyl phosphite, 4,4-butylidene(3-methyl-6-t-butylphenylditridecyl) phosphite, and octyldiphenyl phosphite.

[0036] From the viewpoint of reducing carbon dioxide emissions, the content of the material derived from biological resources (biomass) in the stretch film may be 8% by mass or more, 9% by mass or more, or 10% by mass or more. Examples of the material derived from biological resources (biomass) include the above-mentioned plant-based plasticizers.

[0037] The thickness of the stretch film may be 8 μm or more, 9 μm or more, 10 μm or more, or 11 μm or more, from the viewpoint of improving the strength of the stretch film and making it more resistant to tearing. The thickness of the stretch film may be 15 μm or less, 14 μm or less, 13 μm or less, 12 μm or less, or 11 μm or less, from the viewpoint of further suppressing deformation of the container during prepackaging. From these viewpoints, the thickness of the stretch film may be 8 to 15 μm.

[0038] The storage modulus of the stretch film at 10°C and 35°C is set to 3 x 10 in order to prevent the stretch film from becoming too hard and to easily prevent deformation of the container during prepackaging. 8 Pa or less, and from the viewpoint of making the stretch film stronger and less likely to tear, it is preferable that the stretch film has a hardness of 5 × 10 7 From these viewpoints, the storage modulus of the stretch film at 10 to 35°C may be 5 × 10 or more.7 ~3×10 8 Pa is preferred.

[0039] The storage modulus of the stretch film at 10°C is set to 3×10 in order to prevent the stretch film from becoming too hard at 10°C and to make it easier to prevent deformation of the container during pre-packaging. 8 Pa or less, and from the viewpoint of making the strength of the stretch film at 10°C superior and making the stretch film more resistant to tearing, 8 From these viewpoints, the storage modulus of the stretch film at 10°C may be 2 × 10 or more. 8 ~3×10 8 Pa is preferred.

[0040] The storage modulus of the stretch film at 35°C is set to 6 × 10 in order to prevent the stretch film from becoming too hard at 35°C and make the stretch film less likely to tear. 7 Pa or less, and from the viewpoint of preventing the stretch film from being excessively stretched at 35°C and making the stretch film less likely to tear, 7 From these viewpoints, the storage modulus of the stretch film at 35°C may be 4 × 10 or more. 7 ~6×10 7 Pa is preferred.

[0041] The film impact strength at 10°C and 35°C may be 10 kJ / m or more, 12 kJ / m or more, or 14 kJ / m or more from the viewpoint of making the stretch film more resistant to tearing, and may be 40 kJ / m or less, 38 kJ / m or less, 36 kJ / m or less, 34 kJ / m or less, or 32 kJ / m or less from the viewpoint of preventing the stretch film from becoming too hard and further suppressing deformation of the container during prepackaging. From these viewpoints, the film impact strength at 10°C and 35°C may be 10 to 40 kJ / m.

[0042] The film impact strength at 10°C may be 30 kJ / m or more, 32 kJ / m or more, or 34 kJ / m or more from the viewpoint of making the stretch film more resistant to tearing at 10°C, and may be 40 kJ / m or less, 38 kJ / m or less, or 36 kJ / m or less from the viewpoint of preventing the stretch film from becoming too hard at 10°C and further preventing deformation of the container during prepackaging. From these viewpoints, the film impact strength at 10°C is preferably 30 to 40 kJ / m.

[0043] The film impact strength at 35°C may be 10 kJ / m or more, 12 kJ / m or more, or 14 kJ / m or more from the viewpoint of making the stretch film less likely to tear at 35°C, and may be 20 kJ / m or less, 18 kJ / m or less, or 16 kJ / m or less from the viewpoint of preventing the stretch film from becoming too hard at 35°C and further preventing deformation of the container during prepackaging. From these viewpoints, the film impact strength at 35°C is preferably 10 to 20 kJ / m.

[0044] The stretch film may be used for packaging food products, pre-packaging food products, or packaging non-food products (e.g., medicines). [Example]

[0045] The present invention will be described in more detail below based on examples, but the present invention is not limited to these examples.

[0046] (Examples 1 to 9, Comparative Examples 1 to 6) The amounts (unit: parts by mass) shown in Tables 1 and 2 of polyvinyl chloride resin (PVC, Taiyo Vinyl TH-1300, degree of polymerization: 1300), diisononyl adipate (DINA), epoxidized soybean oil (ESBO), glycerin surfactant (Riken Vitamin), and Ca-Zn higher fatty acid salts (ADEKA Corporation) were kneaded using a Henschel mixer, and then the mixture was extruded using a single-screw extruder (Toshiba Machine, screw diameter: 65 mm, screw effective length L / D: 28) with a die width of 550 mm and a die lip of 0.7 mm. The extrusion was performed at a set temperature of 170 to 200°C and a take-up speed of 50 m / min to obtain a stretch film with a thickness of 11 μm and a width of 300 mm.

[0047] <Measurement of storage modulus> The storage modulus was measured at 10°C and 35°C using a dynamic viscoelasticity measuring device (manufactured by TA Instruments, product name: RSA-G2). The main measurement parameters involved in the measurement are as follows. The measurement results are shown in Tables 1 and 2. Heating rate: 5°C / min Measurement frequency 1Hz

[0048] <Measurement of film impact strength> Using a film impact tester (manufactured by Toyo Seiki Seisakusho, Ltd.), the film impact strength was measured at 10°C and 35°C. The impact sphere used had a diameter of 1 / 2 inch. The measurement results are shown in Tables 1 and 2.

[0049] <Appearance evaluation> At 10°C and 35°C, expanded polystyrene containers manufactured by Denka Polymer Co., Ltd., measuring 25 cm wide x 18 cm deep x 3.3 cm high, were wrapped in stretch film using an automatic wrapping machine (manufactured by Ishida Co., Ltd., product name: WM-AI Super), and the appearance was evaluated based on the following criteria. The evaluation results are shown in Tables 1 and 2. A: There was no tear in the stretch film. B: The stretch film was torn. C: The stretch film could not be unwound.

[0050]

Table 1

[0051]

Table 2

Claims

1. The film contains a polyvinyl chloride resin, an adipic acid plasticizer, a vegetable plasticizer, and an anti-fogging agent, the content of the adipic acid-based plasticizer is 20 to 40 parts by mass relative to 100 parts by mass of the polyvinyl chloride-based resin; the content of the vegetable plasticizer is 16 to 20 parts by mass relative to 100 parts by mass of the polyvinyl chloride resin; A stretch film, wherein the content of the antifogging agent is 1 to 5 parts by mass per 100 parts by mass of the polyvinyl chloride resin.

2. 10. The stretch film of claim 1, wherein the vegetable plasticizer is epoxidized soybean oil.

3. 3. The stretch film according to claim 1, wherein the adipic acid-based plasticizer is diisononyl adipate.

4. 3. The stretch film according to claim 1, wherein the ratio of the mass-based content of the vegetable plasticizer to the mass-based content of the adipic acid-based plasticizer is 0.45 to 0.

9.

5. 3. The stretch film according to claim 1, wherein the anti-fogging agent is a glycerin-based surfactant.

6. 3. The stretch film of claim 1, further comprising a stabilizer.

7. 3. The stretch film according to claim 1, having a thickness of 8 to 15 μm.

8. Storage modulus at 10°C and 35°C is 5 x 10 ７ ~3 x 10 ８ 3. The stretch film according to claim 1, wherein the stretch film has a film impact strength of 10 to 40 kJ / m at 10°C and 35°C.

9. 3. The stretch film according to claim 1, which is used for packaging food products.

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