JP6202660B1 - Food packaging film - Google Patents

Abstract

The present invention is a food packaging film containing a thermoplastic resin and a blue colorant, wherein the film has a tensile modulus of 110 to 180 MPa, and a load during cutting of the film is 80 to 150 cN. Provide food packaging film.

Description

  The present invention relates to a food packaging film.

  2. Description of the Related Art Conventionally, food packaging films are widely used for business purposes in hotels, restaurants, etc., or at home when food is stored or cooked. In recent years, food packaging films have been proposed that contain thermoplastic resins as the main component and further contain colorants such as copper phthalocyanine-based colorants in order to make it easier to visually identify the presence of film fragments in food. (Patent Document 1).

JP2015-7198A

  However, according to the study by the present inventors, in the film as described in Patent Document 1, due to the addition of the colorant, the film may become brittle or the stretchability of the film may be reduced. It turned out to be.

  Then, an object of this invention is to provide the film for food packaging excellent in intensity | strength and elasticity.

  The present invention is a food packaging film containing a thermoplastic resin and a blue colorant, wherein the film has a tensile modulus of 110 to 180 MPa, and a load during cutting of the film is 80 to 150 cN. Provide food packaging film.

  According to the present invention, a food packaging film having excellent strength and stretchability can be provided.

It is a schematic diagram for demonstrating the measuring method of the load at the time of film cutting.

  The film according to the present embodiment contains a thermoplastic resin and a blue colorant. The tensile modulus of the film is 110 to 180 MPa, and the load at the time of cutting the film is 80 to 150 cN. The film according to this embodiment is suitably used as a food packaging film.

  The thermoplastic resin may be a polyvinyl chloride resin, a polyethylene resin, a polypropylene resin, a polystyrene resin, a polyester resin, or the like.

  As the polyvinyl chloride resin, a polyvinyl chloride resin having an average degree of polymerization of 700 to 1300 is preferable from the viewpoint of excellent film moldability, heat resistance and fluidity. The average degree of polymerization in the present invention means an average degree of polymerization measured according to JIS K6720-2.

  The polyvinyl chloride resin may be a vinyl chloride homopolymer, or a copolymer of vinyl chloride and other monomers copolymerizable therewith. 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, and lauryl. Examples thereof include alkyl vinyl ethers such as vinyl ether, maleic acid, acrylonitrile, styrene, methylstyrene, vinylidene chloride, and vinylidene fluoride. When the polyvinyl chloride resin is a copolymer, the content of vinyl chloride units in the copolymer may be 10% by mass or more based on the total amount of monomer units.

  The polyvinyl chloride resin is, for example, a polymer blend with a three-dimensional polymer of acrylonitrile-butadiene-styrene or the like, a post-treatment product of a polyvinyl chloride resin with alcohol, or a post-treatment product of a polyvinyl chloride resin with a chlorine-containing compound. May be. In these cases, the content of the vinyl chloride unit in the polyvinyl chloride resin may be 10% by mass or more based on the total amount of the resin.

  When the thermoplastic resin is a polyvinyl chloride resin, the film may further contain a plasticizer. Examples of the plasticizer include epoxidized linseed oil, epoxidized soybean oil, epoxidized oil such as epoxidized fatty acid alkyl ester, adipic acid ester having a linear or branched alkyl group having 6 to 10 carbon atoms, tributyl acetylcitrate, Hydroxypolycarboxylic acid esters such as acetylated triethyl, fatty acid dibasic acid esters such as dinormalbutyl sebacate, glycol esters such as pentaerythritol ester and diethylene glycol benzoate, phosphate esters such as triphenyl phosphate and tricresyl phosphate Glycerin diacetomonolaurate, chlorinated paraffin, polyester plasticizer and the like. These plasticizers are used alone or in combination of two or more. The content of the plasticizer is appropriately adjusted in the range of, for example, 20 to 50 parts by mass with respect to 100 parts by mass of the polyvinyl chloride resin according to the type of food to be packaged, the packaging form, the packaging method, and the like. .

  The polyethylene resin may be a copolymer having monomer units of low density polyethylene, linear low density polyethylene, linear ultra low density polyethylene, medium density polyethylene, high density polyethylene, ethylene, and the like. Specifically, the polyethylene resin has 3 to 10 carbon atoms such as ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-heptene, 1-octene and the like. α-olefins, vinyl esters such as vinyl acetate and vinyl propionate, unsaturated carboxylic acid esters such as methyl acrylate, ethyl acrylate, methyl methacrylate and ethyl methacrylate, unsaturated compounds such as conjugated dienes and non-conjugated dienes, etc. It may be a copolymer with one or more selected from. The content of ethylene units in the polyethylene resin may be 50% by mass or more based on the total amount of monomer units.

  The content of the thermoplastic resin may be 70% by mass or more based on the total amount of the film.

The blue colorant is, for example, a colorant having a maximum absorption wavelength in the visible light region (380 to 750 nm) at 600 to 750 nm. The absorbance of the blue colorant at the maximum absorption wavelength in the visible light region is preferably at least 2 times, more preferably at least 3 times the absorbance at 470 nm. Specifically, the blue colorant may be copper phthalocyanine (copper phthalocyanine blue), iron (III) hexacyanoferrate ( II ), a mixture of cobaltous oxide and aluminum oxide, indigo or ultramarine. These blue colorants are used singly or in combination of two or more.

  The content of the blue colorant may be 0.5% by mass or more and 2.0% by mass or less based on the total amount of the film.

  The film may further contain other components in addition to the thermoplastic resin and the blue colorant. Other components include anti-fogging agents, heat stabilizers, light stabilizers, lubricants, fillers, plate-out prevention agents, antioxidants, mold release agents, viscosity reducing agents, surfactants, and colorings other than blue colorants. Agents, fluorescent agents, surface treatment agents, crosslinking agents, processing aids, pressure-sensitive adhesives, antistatic agents, ultraviolet absorbers, anti-blocking agents and the like.

  The film may be composed of one layer containing a thermoplastic resin and a blue colorant, or may be composed of a plurality of layers. When the film is composed of a plurality of layers, the film may include, for example, a first surface layer, an intermediate layer, and a second surface layer in this order. In this case, for example, the intermediate layer may contain a blue colorant. The film may further include, for example, an adhesive layer containing an acid-modified polyolefin resin or the like in order to improve the adhesion between the layers, and contains a polyamide-based resin in order to improve the heat resistance of the film. A heat-resistant layer may be further provided.

  The thickness of the film may be preferably 5 μm or more, more preferably 6 μm or more, and preferably 12 μm or less, more preferably 10 μm or less.

  The tensile elastic modulus of the film is 110 to 180 MPa, preferably 110 to 170 MPa, 110 to 160 MPa, 120 to 180 MPa, 120 to 170 MPa, 120 to 160 MPa, 130 to 180 MPa, 130, from the viewpoint of excellent strength and stretchability. It is -170MPa or 130-160MPa.

  The tensile elastic modulus of the film conforms to JIS K7161 (ISO 527-1) and JIS K7127 (ISO 527-3). At 23 ° C., the film is cut into a width of 40 mm and a length of 150 mm or more. It is a tensile elastic modulus obtained by preparing a 10 mm wide sample by folding it in four directions and measuring the sample using a tensile tester (for example, model: E3-L) manufactured by Toyo Seiki Seisakusho Co., Ltd. .

  The load at the time of cutting the film is 80 to 150 cN, preferably 80 to 130 cN, 80 to 100 cN, 90 to 150 cN, 90 to 130 cN, or 90 to 100 cN, from the viewpoint of strength and stretchability.

  A method for measuring the load at the time of cutting the film will be described. FIG. 1 is a schematic diagram for explaining a method for measuring a load during film cutting. First, a film having a width of 30 cm and a length of 100 m is wound around a paper tube having an inner diameter of 27 mm and an outer diameter of 31 mm to form a rectangular parallelepiped decorative box 1 (longitudinal length: 31 cm, short side length: 4.7 cm, The film 2 is pulled out from the state accommodated in the height (4.7 cm) so that the length becomes 30 cm. Next, a push-pull gauge 3 (for example, manufactured by Aiko Engineering Co., Ltd.) is attached to the center 2 a of the leading end portion of the drawn film 2. Next, at 23 ° C., the load when the film 2 is pulled and cut so that the angle formed by the blade direction of the metal saw blade 4 provided in the decorative box 1 and the drawing direction of the film 2 is 45 ° is set at the time of film cutting. Measure as the load.

  The tensile modulus of the film and the load during cutting are adjusted for the plasticizer content (for example, about 18 to 24% by mass) and the blue colorant content (about 0.5 to 2.0% by mass). Therefore, it is within the above range.

  The film is produced by, for example, extruding a composition containing a thermoplastic resin and a blue colorant. Specifically, the composition is supplied to a hopper of an extruder, and a target film is obtained by an inflation method, a T-die method, or the like. In general, the film is wound up while being produced, and the wound film is further wound to a desired length such as 20 m, 50 m, etc., and packed into a cosmetic box to obtain a product.

  When the film is composed of a plurality of layers, the film can be obtained by putting the constituent materials of each layer into separate extruders, melt-extruding them, and coextruding each layer by inflation, T-die method or the like and laminating them. At this time, it is preferable to form a film by taking the melt extruded from the T-die as it is while rapidly cooling it with a casting roll or the like.

  For the film thus obtained, depending on the purpose such as reduction of heat shrinkage rate, natural shrinkage rate, suppression of occurrence of width shrinkage, longitudinal stretching between heating rolls, various heat setting, aging For the purpose of imparting and promoting anti-fogging properties, antistatic properties, tackiness, etc., corona treatment, aging treatment, surface treatment such as printing, coating, surface treatment, etc. Also good.

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example, this invention is not limited to an Example.

Using the following thermoplastic resin, blue colorant, and various additives, resin compositions having the compositions shown in Tables 1 and 2 were prepared, and each resin composition was extruded with a T-die extruder, and a film having a thickness of 8.0 μm. Was made.
Thermoplastic resin a1: Polyvinyl chloride resin (average polymerization degree 1000)
Blue colorant b1: Copper phthalocyanine (copper phthalocyanine blue)
Additive c1: Adipic acid-based polyester (number average molecular weight 1800)
Additive c2: Dioctyl adipate additive c3: Epoxidized soybean oil additive c4: Diglycerin fatty acid ester additive c5: Sorbitan fatty acid ester additive c6: Ca / Zn stabilizer

  About each obtained film, the measurement of the tensile elasticity modulus and the load at the time of a cutting | disconnection, and evaluation of intensity | strength, elasticity, film forming property, and productivity were implemented. The results are shown in Tables 1-2.

(Measurement of tensile modulus)
The tensile elastic modulus of the film conforms to JIS K7161 (ISO 527-1) and JIS K7127 (ISO 527-3). At 23 ° C., the film is cut into a width of 40 mm and a length of 150 mm or more. A sample with a width of 10 mm was prepared by folding in four directions, and the sample was measured using a tensile tester (model: E3-L) manufactured by Toyo Seiki Seisakusho Co., Ltd., and the tensile modulus of the film was obtained.

(Measurement of load when cutting)
First, a film having a width of 30 cm and a length of 100 m is wound around a paper tube having an inner diameter of 27 mm and an outer diameter of 31 mm to form a rectangular parallelepiped decorative box 1 (longitudinal length: 31 cm, short side length: 4.7 cm, The film 2 was pulled out from the state of being stored at a height of 4.7 cm so as to have a length of 30 cm. Next, a push-pull gauge 3 (for example, manufactured by Aiko Engineering Co., Ltd.) was attached to the center 2a of the leading end portion of the drawn film 2. Next, at 23 ° C., the load when the film 2 is pulled and cut so that the angle formed by the blade direction of the metal saw blade 4 provided in the decorative box 1 and the drawing direction of the film 2 is 45 ° is set at the time of film cutting. Measured as load.

(Strength evaluation)
Evaluation was made by visually observing the ease of tearing and tearing of the film when the film was placed on a stainless steel bowl.
A: The strength of the film is particularly good.
B: The strength of the film is good.
C: The film lacks strength.
D: The strength of the film is particularly bad, and there are many tears and tears.

(Evaluation of elasticity)
Evaluation was made by visually observing the ease of elongation of the film when the film was put on the stainless steel bowl.
A: The stretchability of the film is particularly good.
B: The stretchability of the film is good.
C: The film lacks elasticity.
D: The stretchability of the film is particularly bad.

(Evaluation of film formability)
Each resin composition was extruded with a T-die extruder to form a film, and the film forming property was evaluated by observing the appearance of the obtained film. The evaluation criteria are as follows. In addition, if evaluation is A or B, it can be said that it is excellent in film forming property.
A: A film having a substantially uniform thickness was obtained.
B: Unevenness was observed in the thickness of the film, and burns were generated by long-time extrusion.
C: Unevenness of film thickness was severe and burns occurred in a relatively short time.

(Productivity evaluation)
Productivity is evaluated by counting the number of occurrences per day of production troubles (holes, film breaks, slit defects, etc.) that occur when a film is formed by extruding each resin composition with a T-die extruder. did. The evaluation criteria are as follows. In addition, if evaluation is A or B, it can be said that it is excellent in productivity.
A: Production trouble frequency 0-2 times / day B: Production trouble frequency 3-4 times / day C: Production trouble frequency 5 times / day or more

  1 ... Cosmetic box, 2 ... Film, 3 ... Push-pull gauge, 4 ... Metal saw blade.

Claims (3)

A copolymer of vinyl chloride with at least one monomer selected from vinylidene chloride, olefin, vinyl ester, alkyl ester of unsaturated acid, alkyl vinyl ether, maleic acid, acrylonitrile, styrene, methylstyrene and vinylidene fluoride, or chloride A thermoplastic resin consisting only of vinyl homopolymer ;
A food packaging film containing a blue colorant,
Food packaging film having a tensile modulus of 110 to 180 MPa and a load upon cutting of the film of 80 to 150 cN (however, an epoxy group-containing acrylic system having a weight average molecular weight of 1,000 to 150,000) Excluding food packaging films containing compounds). The blue colorant is a copper phthalocyanine, hexacyanoferrate (II), iron (III), a first cobalt-aluminum oxide mixtures oxide is at least one selected from the group consisting of indigo and ultramarine, according to claim 1 Food packaging film. A product obtained by packing the food packaging film according to claim 1 or 2 in a cosmetic box.

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