TWI812585B - Film for food packaging and small roll film for food packaging with color box - Google Patents

Abstract

The present invention provides a film for food packaging, which contains a thermoplastic resin, a blue colorant, and a polyester plasticizer with a number average molecular weight of 1,000 to 1,800.

Description

Film for food packaging and small roll film for food packaging with color box

The invention relates to a film for food packaging and a small roll film for food packaging with a color box.

Previously, food packaging films were widely used as business films in hotels, restaurants, etc., or at home for food preservation, cooking, etc. In recent years, in order to easily visually detect the mixing of film fragments into food, a food packaging film has been proposed that contains a thermoplastic resin as a main component and further contains a colorant such as a copper phthalocyanine-based colorant (Patent Document 1).

On the other hand, in films for food packaging, additives such as plasticizers, anti-fogging agents, and stabilizers are generally used for the purpose of imparting functions such as flexibility to the film or for making the film easy to produce.

However, in recent years, coordination with various countries has been studied regarding the specifications and standards of the Food Sanitation Law, and the standard of the amount of additives contained in food packaging films eluted into food has become a problem. One of the most powerful opinions currently is that the amount of additives dissolved into food should meet the assumed standard value of 25 μg/ml in the European Union (EU) Standards × Standards. [Prior Art Documents] [Patent Documents]

[Patent Document 1] Japanese Patent Application Publication No. 2015-7198

[Problems to be Solved by the Invention] An object of the present invention is to provide a food packaging film and a small roll film for food packaging with a color box that can suppress the elution of additives into food and have excellent film forming properties and productivity. [Means to solve the problem]

The invention provides a film for food packaging, which includes: a thermoplastic resin, a blue colorant, and a polyester plasticizer with a number average molecular weight of 1,000 to 1,800.

Based on the total amount of the film, the content of the polyester plasticizer is preferably 6.5% by mass to 12.5% by mass.

The thermoplastic resin may be at least one selected from the group consisting of polyvinyl chloride resin, polyvinylidene chloride resin, polyolefin resin, polystyrene resin, polyester resin and polyamide resin. .

The film may contain 70% by mass or more of at least one selected from the group consisting of polyvinyl chloride-based resins and polyvinylidene chloride-based resins as the thermoplastic resin based on the total amount of the film.

In addition, the present invention provides a small roll of food packaging film with a color box, which includes the food packaging film, a core material of the food packaging film in a small roll, and a color box containing the food packaging film and the core material. , and the color box is provided with a blade for cutting the food packaging film. [Effects of the invention]

According to the present invention, it is possible to provide a film for food packaging and a small roll film for food packaging with a color box that can suppress the elution of additives into food and have excellent film forming properties and productivity.

The film of this embodiment contains a thermoplastic resin, a blue colorant, and a polyester plasticizer with a number average molecular weight of 1,000 to 1,800 (hereinafter also referred to as "prescribed polyester plasticizer"), and can be suitably used Film for food packaging.

The thermoplastic resin can be polyvinyl chloride-based resins such as polyvinyl chloride; polyvinylidene chloride-based resins such as polyvinylidene chloride; polyolefin-based resins such as polyethylene, polypropylene, and ethylene-vinyl acetate copolymer saponified products; Diene-styrene copolymer, acrylonitrile-styrene copolymer, polystyrene, styrene-butadiene-styrene copolymer, styrene-isoprene-styrene copolymer, styrene-acrylic acid copolymer Polystyrene resins such as polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate and other polyester resins; 6-nylon, 6,6-nylon, 12 -Nylon and other polyamide resins, etc. From the viewpoint of excellent handleability, the thermoplastic resin is preferably a polyvinyl chloride-based resin or a polyvinylidene chloride-based resin.

As the polyvinyl chloride-based resin, from the viewpoint of excellent film formability, heat resistance, and fluidity, a polyvinyl chloride-based resin having an average degree of polymerization of 700 to 1,300 is preferred. The average degree of polymerization in this specification refers to the average degree of polymerization measured based on Japanese Industrial Standards (JIS) K6720-2.

The polyvinyl chloride-based resin may be a vinyl chloride homopolymer (polyvinyl chloride resin) from the viewpoint of excellent mechanical properties, or may be vinyl chloride and other monomers copolymerizable with it for the purpose of imparting other characteristics. of copolymers. 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; and alkanes of unsaturated acids such as methyl acrylate and methyl methacrylate. esters; alkyl vinyl ethers such as lauryl vinyl ether; maleic acid, acrylonitrile, styrene, methylstyrene, vinylidene fluoride, etc. When the polyvinyl chloride-based resin is a copolymer, the content of the vinyl chloride units in the copolymer may be 10% by mass or more based on the total amount of monomer units. From the perspective of excellent mechanical properties, 30% by mass is preferred. % or more, more preferably 50 mass% or more. The upper limit of the content of vinyl chloride units in the copolymer is not particularly limited, but may be, for example, 99 mass % or less based on the total amount of monomer units.

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

The polyvinylidene chloride-based resin may be a vinylidene chloride homopolymer (polyvinylidene chloride resin). For example, it may contain vinylidene chloride and other monomers that can be copolymerized with vinylidene chloride as monomers. copolymer of units. Other monomers can be vinyl chloride, acrylates of acrylic acid and alcohols with 1 to 8 carbon atoms, methacrylates of methacrylic acid and alcohols with 1 to 8 carbon atoms, vinyl esters of aliphatic carboxylic acids, unsaturated aliphatic Carboxylic acids, olefins, vinyl ethers, etc. In addition, the copolymer of vinylidene chloride and vinyl chloride is considered to be a polyvinylidene chloride-based resin.

From the viewpoint of film formability and heat resistance, the content of the vinylidene chloride units in the polyvinylidene chloride-based resin can be, for example, 60 mass% or more or 70 mass% or more based on the total amount of monomer units. , or more than 80 mass%. The upper limit of the content of vinylidene chloride units in the polyvinylidene chloride-based resin is not particularly limited, but may be, for example, 99 mass % or less based on the total amount of monomer units. The content of vinylidene chloride units can be measured by Nuclear Magnetic Resonance (NMR) equipment.

The weight average molecular weight of the polyvinylidene chloride-based resin may be, for example, 40,000 to 180,000, 60,000 to 160,000, or 80,000 to 140,000. The weight average molecular weight of polyvinylidene chloride-based resin can be measured by gel permeation chromatography (GPC) using polystyrene with a known molecular weight as a standard material.

The conditions of the GPC method used for measuring the weight average molecular weight of polyvinylidene chloride-based resin are as follows. As a measuring device, a gel chromatograph Alliance GPC2000 manufactured by Waters Corporation was used. A sample in which a polyvinylidene chloride-based resin was dissolved in tetrahydrofuran so as to become 0.5 wt% (weight percent) was used as a sample. Column: TSKgel GMHHR-H(S)HT 30 cm×2, TSKgel GMH6-HTL 30 cm×2 manufactured by Tosoh Co., Ltd. Mobile phase: Tetrahydrofuran Detector: Differential refractometer Flow rate: 1.0 mL/min Column temperature :20℃ Injection volume: 500 μL

From the viewpoint of excellent productivity, the content of the thermoplastic resin may be 70 mass% or more or 75 mass% or more based on the total amount of the film, and may be 85 mass% or less or 80 mass% or less. It is preferable that the content of polyvinyl chloride-based resin or polyvinylidene chloride-based resin is within the above range.

The blue colorant has a maximum absorption wavelength in the visible light region (380 nm to 750 nm), for example, between 600 nm and 750 nm. The absorbance at the maximum absorption wavelength of the blue colorant in the visible light region is preferably 2 times or more, more preferably 3 times or more, of the absorbance at 470 nm. Specifically, the blue colorant may be copper phthalocyanine (copper phthalocyanine blue), hexacyanoferric(ii)iron(III)ate, cobalt oxide×alumina mixture, indigo, ultramarine, or the like.

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

The number average molecular weight of the polyester plasticizer is 1,000 to 1,800. From the viewpoint of further suppressing the dissolution of additives into food, it is preferably 1,200 to 1,800, more preferably 1,300 to 1,800, and still more preferably 1,400 to 1,800. , the best value is 1500~1800. The number average molecular weight in the present invention is a polystyrene-converted number average molecular weight measured by GPC (for example, model: Agilent 1260 Infinity GPC manufactured by Agilent Technologies Co., Ltd.).

The conditions for GPC in measuring the number average molecular weight of the polyester plasticizer are as follows. As a measuring device, a gel chromatograph Alliance GPC2000 manufactured by Waters Corporation was used. After completely dissolving 30 mg of the sample in 20 mL of o-dichlorobenzene at 145°C, the solution was filtered using a sintered filter with a pore size of 0.45 μm, and the filtrate was used as the sample solution. Other conditions are as stated below. Column: TSKgel GMHHR-H(S)HT 30 cm×2, TSKgel GMH6-HTL 30 cm×2 manufactured by Tosoh Co., Ltd. Mobile phase: o-dichlorobenzene Detector: Differential refractometer Flow rate: 1.0 mL/min Column temperature: 140°C Injection volume: 500 μL

Examples of the polyester plasticizer include aliphatic polybasic acid polyester plasticizers. The aliphatic polybasic acid-based polyester plasticizer may be, for example, a polyester resin composed of aliphatic polybasic acids such as adipic acid and sebacic acid and polyhydric alcohols such as ethylene glycol, propylene glycol and butylene glycol. Specific examples of the aliphatic polybasic acid-based polyester plasticizer include poly(ethylene glycol/adipate) ester, poly(1,3-butanediol/adipate) ester, and poly(1 , 4-butanediol/adipate) ester, poly(propylene glycol/sebacic acid) ester, etc. These polyester plasticizers can be used individually by 1 type, or in combination of 2 or more types.

From the viewpoint of further suppressing the dissolution of additives into food, the content of the specified polyester plasticizer is preferably 6.5 mass% or more, more preferably 7.0 mass% or more, based on the total amount of the film, and still more preferably It is 8.0 mass % or more, and it is especially preferable that it is 10.0 mass % or more. From the viewpoint of better film forming properties and productivity, the content of the specified polyester plasticizer is preferably 12.5% by mass or less, more preferably 12.0% by mass or less based on the total amount of the film. From the viewpoint of further suppressing the elution of additives into food and improving film-forming properties and productivity, the content of the specified polyester plasticizer is preferably 6.5% by mass to 12.5% by mass based on the total amount of the film. %, 6.5 mass% to 12.0 mass%, 7.0 mass% to 12.5 mass%, 7.0 mass% to 12.0 mass%, 8.0 mass% to 12.5 mass%, 8.0 mass% to 12.0 mass%, 10.0 mass% to 12.5 mass%, Or 10.0% by mass to 12.0% by mass.

In addition to the thermoplastic resin, blue colorant, and prescribed polyester-based plasticizer, the film may further contain other components. Examples of other components include: heat stabilizers, light stabilizers, plasticizers other than specified polyester-based plasticizers, lubricants, fillers, anti-precipitation agents, antioxidants, release agents, viscosity reducing agents, Surfactants, colorants other than blue colorants, fluorescent agents, surface treatment agents, cross-linking agents, processing aids, adhesives, antistatic agents, ultraviolet absorbers, anti-caking agents, etc.

The film may include one layer containing a thermoplastic resin, a blue colorant, and a specified polyester-based plasticizer, or may include multiple layers. When the film includes multiple 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 first surface layer and the second surface layer may contain a thermoplastic resin and a predetermined polyester plasticizer, and the intermediate layer may contain a thermoplastic resin and a blue colorant. In order to improve the adhesion between the layers, for example, the film may further include an adhesive layer containing an acid-modified polyolefin resin, and in order to improve the heat resistance of the film, the film may further include a heat-resistant layer containing a polyamide-based resin. When the thermoplastic resin is a polyvinyl chloride-based resin, the film preferably includes a layer containing a thermoplastic resin (polyvinyl chloride-based resin), a blue colorant, and a predetermined polyester-based plasticizer.

From the viewpoint of efficiently blocking external air from contacting the food, the thickness of the film is preferably 5 μm or more, more preferably 6 μm or more, and from the viewpoint of excellent handleability, the film thickness is preferably 25 μm or less, more preferably Below 12μm.

The elution amount of the additive contained in the film is preferably 25 μg/ml or less, more preferably 20 μg/ml or less, respectively, as the heptane elution amount and the isooctane elution amount measured according to the following procedure.

(Amount of heptane dissolved)

A sample of a fixed area was cut out from the film, and the sample was immersed in 2 ml of heptane relative to 1 cm ² of the surface area of the sample at a temperature of 25° C. for 1 hour. Next, the heptane solution after taking out the sample was evaporated to dryness, and the mass of the solid matter was measured to determine the amount of additive elution from the film into heptane.

(dissolved amount of isooctane)

A sample of a fixed area was cut out from the film, and the sample was immersed in 2 ml of isooctane relative to 1 cm ² of the surface area of the sample for 30 minutes at a temperature of 25°C. Next, the isooctane solution after taking out the sample was evaporated to dryness, and the mass of the solid matter was measured to determine the elution amount of the additive from the film into isooctane.

The film is produced by mixing a thermoplastic resin, a blue colorant, and a specified polyester-based plasticizer using a mixer such as a V-shaped mixer, a belt mixer, a Henschel mixer, and a high-speed mixer. The composition is mixed and, if necessary, kneaded using a kneading machine such as a mixing roller, a Banbury mixer, or a kneader to obtain the composition, and then, for example, extrusion molding is performed. Specifically, this composition is supplied to the hopper of an extruder, and an expansion method, a T-die method, etc. are used to obtain a target film. Usually, the film is rolled up as it is being made, and the rolled film is further re-rolled into various desired lengths (into small rolls) such as 20 m, 50 m, etc., and is put into a color box to become a finished product. . That is, the film in this embodiment may be in the form of a small roll film for food packaging, or may be in the form of a small roll film for food packaging with a color box.

Specifically, as shown in FIG. 1 , the small roll of food packaging film 1 with a color box may be in the following form: it is provided with the food packaging film 2 , the core material 3 in which the food packaging film 2 is rolled, and the food packaging film 2 stored therein. The color box 4 includes the food packaging film 2 and the core material 3, and the color box 4 is provided with a blade 5 for cutting the food packaging film 2. The materials of the core material 3 and the color box 4 are not particularly limited. From the viewpoint of making it easy to recognize the color of the film 2 from the outside, it is preferable that at least a part of the color box 4 be transparent or have holes opened to an extent that the function of the color box 4 is not impaired.

When the film contains multiple layers, the film is obtained by putting the constituent raw materials of each layer into different extruders and melt-extruding them, and then laminating the layers after co-extruding them by expansion, T-die method, etc. . At this time, it is preferable to directly retrieve the molten material extruded from the T-shaped mold while rapidly cooling it using a casting roll or the like to form a film.

In order to reduce the thermal shrinkage rate, natural shrinkage rate, etc., and suppress the occurrence of width shrinkage, the film obtained in the above manner can be subjected to heat treatments such as longitudinal stretching between heating rollers, various heat fixation, aging, etc., in order to impart and promote anti- Fog properties, antistatic properties, adhesive properties, etc. The film obtained in the above manner can also be subjected to corona treatment, aging and other treatments, surface treatments such as printing and coating, and surface processing.

The film described above is a film that allows the packaged food to be visually recognized from the outside. In addition, the film is a film (stretched film) having stretchability (also called elasticity).

The film of this embodiment can be a food classification film used for food classification. If the film of this embodiment is used, two or more types of food can be classified into at least two groups according to the type of food. That is, for example, the first type of food may be packaged with the film of this embodiment and classified into the first group. On the other hand, the second type of food may be packaged with a film having a different color from the film of this embodiment or a colorless film and classified into the first group. Group 2.

Specifically, for example, when there is a first food containing a first allergenic substance and a second food containing a second allergenic substance, the first food is classified as being provided to people with allergies to the first type. On the other hand, the second food is classified into the first group of foods for people who do not have allergic symptoms to the second allergic substance. 2 groups. In this example, the occurrence of an accident in which the allergic substance is provided to a person who has allergic symptoms to the first allergic substance or the second allergic substance can be suppressed. [Example]

Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to the examples.

After putting the thermoplastic resin, blue colorant, and various additives shown in Table 1 and Table 2 into a high-speed mixer, stir the material while raising the temperature from normal temperature to 130°C. After mixing, cool to Take out the resin composition at the time point of 70°C, and use an f40 mm single-screw extruder (L/D=20) equipped with a T-shaped die (width: 350 mm, gap: 0.4 mm) at a resin temperature of 200°C. Each resin composition was extruded to prepare a film with a thickness of 8 μm. In addition, the numerical values in the table are values converted from solid content and represent mass %.

Thermoplastic resin a1: Polyvinyl chloride-based resin (manufactured by Taiyo Vinyl Corporation, "TH-1000", average degree of polymerization: 1000) Blue colorant b1: Copper phthalocyanine (copper phthalocyanine blue , manufactured by Dainichi Seika Co., Ltd., "NX-053 Blue") Additive c1: Polyester plasticizer (manufactured by ADEKA Co., Ltd., "PN-150", number average molecular weight: 1000, Adipic acid-based polyester) Additive c2: Polyester-based plasticizer (manufactured by J-Plus Co., Ltd., "D623", number average molecular weight: 1800, adipic acid-based polyester) Additive c3: Polyester-based plasticizer Additive (manufactured by J-Plus Co., Ltd., "D620N", number average molecular weight: 800, adipic acid-based polyester) Additive c4: Polyester-based plasticizer (manufactured by ADEKA Co., Ltd., "P -200", number average molecular weight: 2000, adipic acid-based polyester) Additive c5: dioctyl adipate (manufactured by Shinnippon Rika Co., Ltd., "Sanso Cizer DOA") Additive c6: Epoxidized soybean oil (manufactured by Sanwa Synthetic Chemical Co., Ltd., "Chemicizer SE-100") Additive c7: glycerol fatty acid ester (manufactured by Riken Vitamin Co., Ltd., "XO-100" ") Additive c8: Ca/Zn stabilizer (manufactured by ADEKA Co., Ltd., "SC-308E")

For each obtained film, the elution amount of the additive was measured by the following procedure.

(Amount of heptane dissolved)

Cut a 5 cm × 10 cm sample from the film so that the total surface area of the front and back becomes 100 cm ² , and immerse the sample in 2 ml of heptane relative to the surface area of 1 cm ² of the sample for 1 hour at a temperature of 25°C. . Then, the test solution after taking out the sample was evaporated to dryness at 105°C and left to cool. The mass of the solid component after cooling was measured and calculated according to the following formula to determine the elution amount of the component from the film into heptane. In the case of polyvinyl chloride-based resin, if it is 150 μg/ml or less, it can be said to be good, and if it is 30 μg/ml or less, it can be said to be very good.

Evaporation residue (μg/ml) = weight of solid components (μg)/amount of test solution (ml)

(dissolved amount of isooctane)

Cut a 5 cm × 10 cm sample from the film so that the total surface area of the front and back becomes 100 cm ² , and immerse the sample in 2 ml of isooctane relative to 1 cm ² of the surface area of the sample for 30 seconds at a temperature of 25°C. minute. Then, the test solution after taking out the sample was evaporated to dryness at 105°C and left to cool. The mass of the solid matter after cooling was measured and calculated according to the following formula to determine the elution amount of the component from the film into isooctane. In the case of polyvinyl chloride-based resin, if it is 90 μg/ml or less, it can be said to be good, and if it is 30 μg/ml or less, it can be said to be very good.

Evaporation residue (μg/ml) = weight of solid components (μg)/amount of test solution (ml)

(Evaluation of film-forming properties) Each resin composition was extruded using a T-die extruder at a resin temperature of 200° C. to form a film, and the appearance of the obtained film was observed to evaluate the film-forming properties. The evaluation criteria are as follows. Furthermore, if the evaluation is A or B, it can be said that film forming properties are excellent. A: A film with approximately uniform thickness can be obtained, and no yellowing occurs during 24 hours of extrusion. B: Slight unevenness was seen in the thickness of the film, and yellowing occurred during 24 hours of extrusion. C: The thickness of the film is seriously uneven, and yellowing occurs during 8 hours of extrusion.

(Evaluation of Productivity) Count the number of production failures (hole openings, film breakage, and slit defects) that occur when each resin composition is extruded using a T-die extruder at a resin temperature of 200°C to form a film. The number of occurrences per 24 hours is used to evaluate productivity. The evaluation criteria are as follows. Furthermore, if the evaluation is A or B, it can be said that productivity is excellent. A: The number of production failures is 0 to 2 times B: The number of production failures is 3 to 4 times C: The number of production failures is more than 5 times

[Table 1]

[Table 2]

1‧‧‧Small roll film for food packaging with color box 2‧‧‧Film for food packaging 3‧‧‧Core material 4‧‧‧Color box 5‧‧‧Blade

Figure 1 is a schematic diagram showing a small roll film for food packaging with a color box.

1‧‧‧Small roll film for food packaging with color box

2‧‧‧Food packaging film

3‧‧‧Core material

4‧‧‧Color Box

5‧‧‧Blade

Claims (2)

A film for food packaging, which includes: a thermoplastic resin, a blue colorant, and a polyester plasticizer with a number average molecular weight of 1000 to 1800. The content of the polyester plasticizer is based on the total amount of the film. It is 7 mass% to 12.5 mass%, and the thermoplastic resin is polyvinyl chloride resin or polyvinylidene chloride resin. A small roll of film for food packaging with a color box, which includes the film for food packaging as described in item 1 of the patent application scope, a core material with the film for food packaging in a small roll, and a small roll of film for food packaging containing the film for food packaging. A color box including a film and the core material, and a blade for cutting the food packaging film is provided in the color box.