Food packaging film

Abstract

To provide a food packaging film capable of preventing food from drying out.SOLUTION: One embodiment relates to a food packaging film in which the reduction ratio of the mass of water is less than 20% when a food tray containing 50 g of water is packaged and left for 72 hours under atmospheric pressure, at a temperature of 5°C, and at a relative humidity of 20%.

Description

[Technical field]

[0001] An embodiment of the present invention relates to a food packaging film and a packaged food. [Background technology]

[0002] Food packaging films are used in large quantities as so-called wrap films, which are used as food packaging materials for meat, fresh fish, fruits and vegetables, etc. in supermarkets (for example, Patent Document 1). They are also used in restaurants and ordinary homes for preserving food such as cooking ingredients and cooked foods. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2002-264284 A Summary of the Invention [Problem to be solved by the invention]

[0004] Food packaging films have a problem in that the food contents dry out over time. This can shorten the shelf life of the food and cause the food to look bad, which can discourage users from purchasing the food. Therefore, an object of an embodiment of the present invention is to provide a food packaging film that can prevent food from drying out. Another object of the present invention is to provide a packaged food that can prevent food from drying out. [Means for solving the problem]

[0005] The present invention includes the following embodiments, but is not limited to the following embodiments. (1) A food packaging film that, when used to package a food tray containing 50 g of water and left for 72 hours under atmospheric pressure, a temperature of 5°C, and a relative humidity of 20%, loses less than 20% of the water by mass. (2) The food packaging film according to (1) above, having a thickness of 7 μm or more and less than 20 μm. (3) The food packaging film according to (1) or (2) above, which contains a polymer and a plasticizer, and the content of the plasticizer is more than 30 parts by mass and less than 50 parts by mass per 100 parts by mass of the polymer. (4) The food packaging film according to any one of (1) to (3) above, which contains polyvinyl chloride. (5) The food packaging film according to (4) above, wherein the degree of polymerization of the polyvinyl chloride is more than 800 and less than 1,500. (6) A food packaging film containing polyvinyl chloride and a plasticizer, wherein the degree of polymerization of the polyvinyl chloride is more than 800 and less than 1,500, and the content of the plasticizer is more than 30 parts by mass and less than 50 parts by mass per 100 parts by mass of the polyvinyl chloride. (7) A packaged food comprising the food packaging film according to any one of (1) to (6) above and a food packaged in the food packaging film. Effect of the Invention

[0006] According to an embodiment of the present invention, it is possible to provide a food packaging film capable of preventing food from drying out. Also, according to another embodiment of the present invention, it is possible to provide a packaged food product capable of preventing food from drying out. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a photograph of a package used to measure the rate of water mass loss in the examples. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] An embodiment of the present invention will be described below, but the present invention is not limited to the following embodiment. <Food packaging film> In an embodiment of the present invention, the food packaging film satisfies the following properties. When a food tray containing 50 g of water is packaged and left for 72 hours under atmospheric pressure, at a temperature of 5°C and a relative humidity of 20%, the mass loss of the water is less than 20%. The loss rate can be calculated using the following formula. Loss rate (%) = [(50(g) - mass of water after 72 hours (g))] / 50(g) x 100

[0009] When the weight loss rate is less than 20%, the moisture of the food contents is prevented from permeating the food packaging film and evaporating, and the food is prevented from drying out. Preventing the food from drying out allows the food to be stored for a long period of time and maintains a good appearance. The weight loss rate is preferably 18% or less, more preferably 16% or less. The lower limit of the weight loss rate is not particularly limited, and may be, for example, 3% or more.

[0010] The loss rate can be measured by the following method. Prepare a food tray. The area of ​​the opening of the food tray used for measurement is 400 to 500 cm. 2 A food tray suitable for the measurement may have an opening area of, for example, 400 to 500 cm. 2 and a depth of 2.8 to 3.2 cm. A commercially available food tray can be used to measure the rate of shrinkage. An example of a commercially available product is the food container "CN20-23FF" manufactured by Chuo Kagaku Co., Ltd.

[0011] Add 50 g of water to the food tray. The food tray may be added with some or all of the 50 g of water absorbed in an absorbent material such as paper. For example, place a paper towel on the bottom of the food tray, then add 50 g of water and allow the paper towel to absorb the water. The water may be entirely absorbed by the paper towel, or it may be partially absorbed and the rest may not be absorbed. The mass (g) of the food tray is measured before use. When an absorbent material is used, the mass (g) of the material is also measured before use.

[0012] The food tray is wrapped in a food packaging film so that the entire food tray is covered. At this time, the opening of the food tray is covered with a single layer of food packaging film without overlapping. Commercially available hand wrappers can be used for packaging.

[0013] A food tray (sometimes called a "package") containing at least water as its content and wrapped in a food packaging film is left to stand for 72 hours under atmospheric pressure, at a temperature of 5°C, and at a relative humidity of 20%, and the mass (g) of the package is then measured. The rate of water mass loss can be calculated using the following formula. Alternatively, the rate of water mass loss can be calculated using the above formula using the mass (g) of the food tray and absorbent member. If no absorbent member is used, the mass of the absorbent member is 0g. Loss rate (%) = [(mass (g) of package before 72 hours - mass (g) of package after 72 hours)) / 50(g)] x 100

[0014] For example, the atmospheric pressure atmosphere is an atmosphere with an atmospheric pressure of 0.09 to 0.11 MPa, and it is sufficient that the measurement is performed in an atmosphere with an atmospheric pressure of 0.09 to 0.11 MPa and the loss rate is less than 20%.

[0015] The thickness of the food packaging film is preferably 7 μm or more and less than 20 μm. When the thickness is within the above range, the function as a food packaging film can be maintained. When the thickness is 7 μm or more, the moisture loss rate can be made less than 20%, and food can be prevented from drying out. The thickness is more preferably 8 μm or more, even more preferably 10 μm or more, and particularly preferably 13 μm or more. When the thickness is less than 20 μm, flexibility can be maintained and a good usability as a food packaging film can be obtained. The thickness is more preferably 18 μm or less, and even more preferably 16 μm or less.

[0016] The food packaging film may contain a polymer and a plasticizer. The content of the plasticizer is preferably more than 30 parts by mass and less than 50 parts by mass with respect to 100 parts by mass of the polymer. When the content of the plasticizer is within the above range, the film forming property is good and the function as a food packaging film can be maintained. When the content of the plasticizer is more than 30 parts by mass, good film forming property is obtained. The content of the plasticizer is more preferably 35 parts by mass or more, and even more preferably 40 parts by mass or more. When the content of the plasticizer is less than 50 parts by mass, the weight loss rate of water can be maintained at 20% or less, and the drying of food can be prevented. The content of the plasticizer is more preferably 48 parts by mass or less, more preferably 45 parts by mass or less, and may be 43 parts by mass or less.

[0017] Examples of the polymer include polyolefins such as polyethylene, polypropylene, and ethylene-propylene copolymers; polyesters such as polyethylene terephthalate and polyethylene naphthalate; styrene-based polymers such as polystyrene and styrene-butadiene-styrene block copolymers; and chlorine-based polymers such as polyvinyl chloride and polyvinylidene chloride. The food packaging film may contain only one type of polymer, or may contain two or more types of polymers. Since the food packaging film containing polyvinyl chloride has good functions as a wrap film, polyvinyl chloride can be preferably used.

[0018] The degree of polymerization of polyvinyl chloride is preferably more than 800 and less than 1500. When the degree of polymerization of polyvinyl chloride is within the above range, the film formability is good and the function as a food packaging film can be maintained. When the degree of polymerization of polyvinyl chloride is more than 800, it can be formed into a film shape and the function as a food packaging film can be maintained. The degree of polymerization of polyvinyl chloride is more preferably 900 or more, and even more preferably 950 or more. When the degree of polymerization of polyvinyl chloride is less than 1500, the amount of plasticizer used can be reduced and the weight loss rate of water can be maintained less than 20%. The degree of polymerization of polyvinyl chloride is more preferably 1400 or less, even more preferably 1200 or less, and particularly preferably 1100 or less. In an embodiment of the present invention, the degree of polymerization of polyvinyl chloride is an average degree of polymerization converted from the K value measured according to JIS K7367-2:1999.

[0019] Examples of polyvinyl chloride include TK-1000, TK-1300, TK-1400, etc. manufactured by Shin-Etsu Chemical Co., Ltd.; S1001N, S1003, etc. manufactured by Kaneka Corporation.

[0020] Examples of the plasticizer include diisononyl adipate, epoxidized soybean oil, di-normal alkyl adipate, dioctyl adipate, polyester compounds, etc. The food packaging film may contain only one type of plasticizer, or may contain two or more types of plasticizers.

[0021] The food packaging film may further contain additives such as lubricants, antifogging agents, and stabilizers. Examples of lubricants include aliphatic hydrocarbon-based lubricants, higher aliphatic alcohol-based lubricants, fatty acid-based lubricants, aliphatic amide-based lubricants, fatty acid ester-based lubricants, metal soaps, and silicone oils. Examples of stabilizers include lead-based stabilizers, tin-based stabilizers, organometallic salt-based stabilizers, metal soap-based stabilizers, antimony-based stabilizers, phosphate-based stabilizers, and epoxidized oil-based stabilizers. Examples of antifogging agents include sorbitan fatty acid esters, polyglycerin fatty acid esters, and triethylene glycol. The food packaging film may contain only one type of additive or a combination of two or more types of additives.

[0022] The method for producing the food packaging film is not particularly limited, and the film can be produced by known production methods such as melt extrusion, calendar molding, and casting. Considering the ease of handling and simplification of production equipment, the method of extrusion molding by melt extrusion is preferable. The method for producing the food packaging film includes, for example, melt-kneading the molding material of the food packaging film of the above embodiment, extruding the molding material through a die to form a film, cooling the film, and winding it up with a winder. The size of the food packaging film can be set according to the application. The width of the food packaging film may be, for example, 250 mm, 280 mm, 300 mm, 330 mm, 350 mm, 400 mm, 450 mm, or 500 mm. The winding length may be, for example, 500 m, 750 m, 1000 m, or 1200 m.

[0023] <Packaged food> In an embodiment of the present invention, the packaged food includes the food packaging film of the above embodiment and a food packaged with the food packaging film. The packaged food may further include a food tray. The packaged food may include, for example, the food packaging film of the above embodiment, and a food and a food tray packaged with the food packaging film. From the viewpoint of preventing evaporation of moisture, it is preferable that the food tray is packaged with at least the opening covered with the food packaging film, and it is more preferable that the entire food tray, including the outside of the bottom, is packaged with the food packaging film covered. EXAMPLES

[0024] The embodiments of the present invention will be described in detail with reference to examples, but the embodiments of the present invention are not limited to the following examples.

[0025] [Experimental Examples 1-7] (Film Creation) A molding material containing polyvinyl chloride (degree of polymerization 1300) and a plasticizer (45 parts by mass per 100 parts by mass of polyvinyl chloride) was used to produce a film (750 mm in the extrusion direction × 300 mm in the width direction) with the thickness shown in Table 1 by melt extrusion molding.

[0026] (Measurement of water mass loss rate (%)) Two sheets of kitchen paper (Hattori Paper Co., Ltd.'s "Kitchen Paper") were placed in a Chuo Kagaku Co., Ltd.'s "CN20-23FF" food tray, 50 g of water was poured in, and the tray was then wrapped in film using a hand wrapper (ARC Co., Ltd.'s "Poly Wrapper40") to obtain a package. The total mass of the tray and kitchen paper was 11 g. The package was placed in a thermostatic chamber and left to stand for 72 hours under atmospheric pressure, at a temperature of 5°C and a relative humidity of 20%. After standing, the mass of the package was measured and the rate of water mass loss was calculated using the following formula. Loss rate (%) = {[50(g)-(mass of package after 72 hours (g)-11(g))] / 50(g)} x 100 = [(mass of package before 72 hours (g) - mass of package after 72 hours (g)) / 50(g)] x 100

[0027] (Measurement of film thickness (μm)) The thickness of the film was measured using a contact-type thickness gauge (GT2-A12KL, manufactured by Keyence Corporation). During the measurement, the thickness was measured at nine predetermined positions where the extrusion direction of the film and the width direction, which is perpendicular to the extrusion direction, intersected, and the average value of these measurements was taken as the film thickness. The measurement points in the extrusion direction were 50 mm, 100 mm, and 150 mm apart from the tip of the film at 50 mm intervals. In contrast, the measurement points in the width direction were 25 mm, 150 mm, and 275 mm from one end of the film.

[0028] (Film evaluation) (Evaluation of film-forming properties) The molding materials were used to prepare films by melt extrusion molding, and the film formability was evaluated based on the state of the films. The evaluation criteria are as follows: A: The molding material is heated and melted, and the molding material coming out of the extruder is pulled by a take-off machine to produce a film. B: Even if the molding material is heated and melted, and the molding material coming out of the extrusion molding machine is pulled by a take-off machine, a film cannot be produced.

[0029] (Functionality evaluation) The trays were wrapped in film using a hand wrapper ("Poly Wrapper 40" manufactured by ARC Corporation), and functionality was evaluated based on the wrapping condition and the feel when wrapping. The evaluation criteria are as follows: A: It is possible to wrap, and the film stretches well, making it easy to wrap. B: It is possible to wrap, but the film does not stretch sufficiently, making wrapping difficult. C: The film is torn or too hard to stretch, making it impossible to wrap.

[0030] [Table 1]

[0031] The films of Experimental Examples 1 and 7 were not capable of wrapping food trays and could not be used as food packaging films. Foods packaged using the films of Experimental Examples 2 to 6, which had a loss rate of less than 20%, were able to prevent the food from drying out.

[0032] [Experimental Examples 8-13] (Film Creation) A molding material containing polyvinyl chloride (degree of polymerization 1300) and a plasticizer (amount shown in Table 2 per 100 parts by mass of polyvinyl chloride) was used to produce a film having a thickness of 10 μm by melt extrusion molding.

[0033] (Film evaluation) The films of Experimental Examples 8 to 13 were evaluated in the same manner as Experimental Examples 1 to 7. The results are shown in Table 2.

[0034] [Table 2]

[0035] The films of Experimental Examples 9 and 13 were not capable of wrapping food trays and could not be used as food packaging films. Foods packaged using the films of Experimental Examples 10 to 12, which had a loss rate of less than 20%, were able to prevent the food from drying out.

[0036] [Experimental Examples 14-18] (Film Creation) A molding material containing polyvinyl chloride (degree of polymerization shown in Table 3) and a plasticizer (45 parts by mass per 100 parts by mass of polyvinyl chloride) was used to produce a film having a thickness of 10 μm by melt extrusion molding.

[0037] (Film evaluation) The films of Experimental Examples 14 to 18 were evaluated in the same manner as Experimental Examples 1 to 7. The results are shown in Table 3.

[0038] [Table 3]

[0039] The films of Experimental Examples 15 and 18 were not able to wrap food trays and could not be used as food packaging films. Foods packaged using the films of Experimental Examples 16 and 17, which had a loss rate of less than 20%, were able to prevent the food from drying out.

Claims

1. This food packaging film is used to package a food tray containing 50 g of water, and when the food tray is left for 72 hours under atmospheric pressure, at a temperature of 5°C, and at a relative humidity of 20%, the mass loss of the water is less than 20%.

2. The food packaging film according to claim 1 , which has a thickness of 7 μm or more and less than 20 μm.

3. 2. The food packaging film according to claim 1, comprising a polymer and a plasticizer, the content of the plasticizer being more than 30 parts by mass and less than 50 parts by mass per 100 parts by mass of the polymer.

4. 2. The food packaging film according to claim 1, which contains polyvinyl chloride.

5. The food packaging film according to claim 4, wherein the degree of polymerization of the polyvinyl chloride is more than 800 and less than 1,500.

6. A packaged food comprising the food packaging film according to any one of claims 1 to 5 and a food packaged in the food packaging film.

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