JP2020196489A - Food packaging film and food packaging bag - Google Patents

Abstract

To provide food packaging films etc. that prevent fresh food such as vegetables from fermenting or spoiling due to action of germs by calcium hydroxide contained in a first resin layer of the food packaging film, and can suppress loss of calcium hydroxide particles.SOLUTION: The present invention is a food packaging film 10 which includes a first resin layer 1 containing first resin and calcium hydroxide particles 1a as the outermost layer, and the first resin contains an ethylene-propylene-butene ternary copolymer.SELECTED DRAWING: Figure 1

Description

The present invention relates to a food packaging film and a food packaging bag.

Conventionally, a food packaging bag that retains the freshness of the contained fresh food (vegetables, etc.) and a food packaging film for producing the food packaging bag are known (for example, Patent Document 1).

The food packaging film of Patent Document 1 is configured as a resin laminate, and includes a first resin layer containing a first resin and calcium hydroxide particles as the outermost layer of the resin laminate.
Further, in the food packaging bag of Patent Document 1, the food packaging film is provided so that the first resin layer is inside the bag, that is, the first resin layer constitutes the inner surface of the bag. It is made by sealing.

In the food packaging bag of Patent Document 1, the calcium hydroxide contained in the first resin layer of the food packaging film causes fresh foods such as vegetables contained therein to be fermented or spoiled by the action of various germs. It suppresses doing.

JP-A-2017-30842

Generally, the food packaging bag of Patent Document 1 is produced by sealing the edge portion of the food packaging film while transporting the food packaging film, but during transportation of the food packaging film or Calcium hydroxide particles may fall off from the food packaging film due to an external force applied to the food packaging film during the sealing of the food packaging film.
In such a case, it is considered that the food packaging bag cannot exhibit sufficient freshness retention.

Further, in the food packaging bag of Patent Document 1, even when the open edge portion is sealed after the fresh food such as vegetables is stored from the open edge side to the inside, the external force applied to the food packaging film causes the bag. , Calcium hydroxide particles may fall off from the inner surface of the bag, and the fallen calcium hydroxide particles may be mixed as foreign matter in fresh food such as vegetables.
It is not preferable from the viewpoint of hygiene that the shed calcium hydroxide particles are mixed into fresh food such as vegetables contained in the food packaging bag as a foreign substance.

As described above, in the food packaging bag of Patent Document 1, although there is a concern about the loss of calcium hydroxide particles, sufficient studies have not been made on suppressing the loss of calcium hydroxide.

In view of such circumstances, it is an object of the present invention to provide a food packaging film and a food packaging bag capable of suppressing the loss of calcium hydroxide particles.

As a result of diligent studies by the present inventor, a food packaging film having a first resin layer containing a first resin and calcium hydroxide particles as the outermost layer was obtained, and the first resin was ethylene-propylene-butene ternary. In a food packaging bag prepared so that the first resin layer constitutes the inner surface of the bag by containing the copolymer, the calcium hydroxide particles are relatively prevented from falling off from the first resin layer. We have found that it can be suppressed and came up with the present invention.

That is, the food packaging film according to the present invention is
A first resin layer containing the first resin and calcium hydroxide particles is provided as the outermost layer.
The first resin contains an ethylene-propylene-butene ternary copolymer.

According to such a configuration, since the first resin contains an ethylene-propylene-butene ternary copolymer, in a food packaging bag prepared so that the first resin layer constitutes the inner surface of the bag. It is possible to prevent the calcium hydroxide particles from falling off from the first resin layer.
As a result, in the food packaging bag, the freshness of fresh foods such as vegetables contained in the bag can be sufficiently maintained, and the slaked calcium hydroxide is contained in the vegetables and the like inside the bag. It can be suppressed from being mixed in the product food of.

In the food packaging film,
The thickness of the first resin layer is preferably 0.01 μm or more and 10 μm or less.

According to such a configuration, the thickness of the first resin layer is 0.01 μm or more and 10 μm or less. Therefore, in the food packaging bag prepared so that the first resin layer constitutes the inner surface of the bag, the said It is possible to more sufficiently prevent the calcium hydroxide particles from falling off from the first resin layer.

In the food packaging film,
Further provided with a second resin layer containing a second resin,
The second resin layer is laminated on one surface of the first resin layer.
The thickness of the second resin layer preferably exceeds 10 μm.

According to such a configuration, it is possible to suppress the breakage of the film while suppressing the loss of calcium hydroxide.
As a result, it is possible to obtain a film having good stretchability while suppressing the shedding of calcium hydroxide particles.

In the food packaging film,
Further provided with a third resin layer containing a third resin,
The third resin layer is laminated on the other surface of the first resin layer facing the one surface.
The thickness of the third resin layer is preferably 0.01 μm or more and 10 μm or less.

According to such a configuration, curling of the film can be suppressed while suppressing the shedding of calcium hydroxide particles.

In the above food packaging film,
The first resin layer preferably contains calcium hydroxide particles of 0.1% by mass or more and 12% by mass or less with respect to the first resin composition containing the first resin.

According to such a configuration, since the first resin layer contains 0.1% by mass or more of calcium hydroxide particles with respect to the first resin composition containing the first resin, the fresh food contained therein. The freshness of (vegetables, etc.) can be maintained more sufficiently.
Further, since the first resin layer contains 11% by mass or less of calcium hydroxide particles with respect to the first resin composition, the film can be easily formed.

In the above food packaging film,
The second resin preferably contains a polyolefin-based homopolymer.

According to such a configuration, it is possible to increase the mechanical strength and heat resistance of the film while suppressing the shedding of calcium hydroxide particles.

In the above food packaging film,
The third resin preferably contains an ethylene-propylene-butene ternary copolymer.

According to such a configuration, curling of the film can be suppressed while suppressing the shedding of calcium hydroxide particles.

The food packaging bag according to the present invention
A food packaging bag made of the food packaging film.
The inner surface of the bag is composed of the first resin layer.

According to such a configuration, since the first resin contains an ethylene-propylene-butene ternary copolymer, the calcium hydroxide particles fall off from the first resin layer constituting the inner surface of the bag. Can be suppressed.
As a result, the freshness of fresh foods such as vegetables contained in the bag can be sufficiently maintained, and the calcium hydroxide that has fallen off is mixed with the produced foods such as vegetables contained in the bag. Can be suppressed.

According to the present invention, it is possible to provide a food packaging film and a food packaging bag that can prevent the calcium hydroxide particles from falling off.

The cross-sectional view which shows the structure of the food packaging film which concerns on this embodiment. (A) is a plan view which shows the whole structure of the food packaging bag which concerns on this embodiment. (B) is a diagram showing a configuration seen from the A side of (a). (A) is a view of the food packaging film according to Example 1 before the scratch test taken from the first resin layer side. (B) is a view of the food packaging film according to Example 1 after the scratch test taken from the first resin layer side. (C) is a view of the food packaging film according to Comparative Example 1 before the scratch test taken from the first resin layer side. (D) is a view of the food packaging film according to Comparative Example 1 after the scratch test, taken from the first resin layer side.

Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

(Film for food packaging)
As shown in FIG. 1, the food packaging film 10 according to the present embodiment includes a first resin layer 1 containing a first resin and calcium hydroxide particles 1a as an outermost layer, and the first resin is ethylene-. Contains a propylene-butene ternary copolymer.
The food packaging film 10 according to the present embodiment is a film capable of suppressing the loss of calcium hydroxide particles, and is therefore excellent in the effect of maintaining the freshness of food.

Further, the food packaging film 10 according to the present embodiment further includes a second resin layer 2 containing a second resin, and the second resin layer 2 is laminated on one surface of the first resin layer 1.
Further, the food packaging film 10 according to the present embodiment further includes a third resin layer 3 containing a third resin, and the third resin layer 3 is formed on the other surface of the first resin layer 1 facing the one surface. It is laminated.
That is, the food packaging film 1 according to the present embodiment has the second resin layer 2 as the central layer, and the first resin layer 1 and the third resin layer 3 are on the surfaces of the second resin layer 2 which is the central layer and which face each other. Each has.
When the food packaging film 10 is composed of only one layer of the first resin layer 1, the first resin layer 1 is the outermost layer.

The second resin layer 2 and the third resin layer 3 are preferably laminated directly on the first resin layer (without interposing another layer).
The food packaging film 10 according to the present embodiment has a first resin layer 1 which is the outermost layer, a second resin layer 2 laminated so as to be in direct contact with the first resin layer 1, and a second resin layer 2 directly. It is preferable that the film has at least three or more layers having a third resin layer 3 laminated so as to be in contact with the outermost layer, and is laminated so as to be in direct contact with the first resin layer 1 which is the outermost layer. It is preferable that the film has a three-layer structure including the second resin layer 2 and the third resin layer 3 laminated so as to be in direct contact with the second resin layer 2.

The food packaging film 10 according to the present embodiment may be non-stretch molded or stretch-molded, but is preferably stretch-molded and biaxially stretch-molded. More preferably.

The first resin layer 1 is composed of a first resin composition containing the first resin and calcium hydroxide particles (hereinafter, also simply referred to as the first resin composition). The first resin layer 1 preferably contains 70% by mass or more of the ethylene-propylene-butene ternary copolymer, and more preferably 80% by mass or more, based on the first resin composition.
The first resin may be an ethylene-propylene-butene ternary copolymer, or may contain other resins. Examples of other resins include crystalline polyolefin resins. As the crystalline polyolefin resin, ethylene, propylene, 1-butene, 1-pentene, 3-methyl-1-pentene, 4-methyl-1-pentene, 1-hexene, 1-octene and the like are used as monomers. Examples thereof include a homopolymer and a binary copolymer, and these can be used alone or in combination of two or more.

The ethylene-propylene-butene ternary copolymer (hereinafter, also referred to as PEB) contained in the first resin is a copolymer containing propylene, ethylene and 1-butene as main components, and is usually obtained by a multi-stage copolymerization method. Resin to be produced.
The PEB preferably has a melting point in the range of 125 to 135 ° C., and more preferably 130 to 132 ° C.
The melting point of PEB is a value measured by the following procedure using an input compensation type DSC device (Diamond DSC manufactured by PerkinElmer).
(I) 5 mg of PEB is weighed, packed in an aluminum sample holder, and set in the DSC device.
(Ii) Under a nitrogen stream, the temperature is raised from −40 ° C. to 300 ° C. at a rate of 20 ° C./min, held at 300 ° C. for 5 minutes, cooled at a rate of 20 ° C./min, and at −40 ° C. Hold for 5 minutes.
(Iii) The temperature is raised to 300 ° C. again at a rate of 20 ° C./min, and the melting point is obtained from the DSC curve obtained at that time. The melting point is the peak temperature of the melting peak (the maximum melting peak when there are a plurality of peaks in the DSC curve) defined in 9.1 (1) of JIS K 7121.

The melt mass flow rate (MFR) of PEB is preferably 0.5 g / 10 minutes or more and 10 g / 10 minutes or less, more preferably 3 g / 10 minutes or more and 8 g / 10 minutes or less, and 4 g / 10 minutes or more and 7 g / 10 minutes or less. More preferred. By setting the MFR in the above range, the first resin can have an appropriate fluidity, so that a film can be produced with an accurate thickness.
The MFR of PEB can be measured using a melt indexer (manufactured by Toyo Seiki Seisakusho) under the conditions of a measurement temperature of 230 ° C. and a load of 2.16 kg according to JIS K 7210: 1999.

The composition of PEB is such that the propylene content is 50% by mass or more and the propylene content is 50% by mass or more because sufficient heat sealability can be ensured at a relatively low temperature (for example, 140 ° C.) while suppressing the shedding of calcium hydroxide particles. The total of the ethylene content and the 1-butene content is preferably less than 50% by mass.
The composition of PEB is preferably such that the propylene content is less than 99% by mass and the total of the ethylene content and the 1-butene content is 1% by mass or more, and the propylene content is 97% by mass. %, And the total of ethylene content and 1-butene content is more preferably 3% by mass or more, propylene content is less than 95% by mass, and ethylene content and 1-butene content. It is more preferable that the total with the butene content is 5% by mass or more.
When the propylene content is less than 97% by mass or less than 95% by mass, the ethylene content and the 1-butene content are preferably 1% by mass or more, respectively.
The propylene content, ethylene content, and 1-butene content mean the contents at the time of preparation.

The thickness of the first resin layer 1 is preferably 0.01 μm or more and 10 μm or less, more preferably 1 μm or more and 8 μm or less, and further preferably 2 μm or more and 5 μm or less.
By setting the thickness of the first resin layer 1 within the above range, a film can be produced at low cost. In addition, since the haze (cloudiness) can be lowered, the visibility of the fresh food (vegetables, etc.) contained in the bag can be improved, and the freshness of the fresh food can be sufficiently improved. Can be retained.
The thickness of the first resin layer 1 can be measured using an electron microscope. Specifically, the cross section of the food packaging film 10 is observed at a magnification of 500 times, the thickness of any 10 points randomly selected in the food packaging film 10 is measured, and these measured values are arithmetically averaged. It can be obtained by

The first resin layer 1 preferably contains 0.1% by mass or more and 12% by mass or less of calcium hydroxide particles 1a with respect to the first resin composition, and is preferably 3% by mass or more and 10% by mass or less of water. It is more preferable that the calcium oxide particles 1a are contained, and it is further preferable that the calcium hydroxide particles 1a are contained in an amount of 5% by mass or more and 9% by mass or less. In the present specification, the mass ratio of the calcium hydroxide particles 1a to the first resin composition means the mass ratio of the calcium hydroxide particles 1a to the first resin composition at the time of blending.

The calcium hydroxide particles 1a preferably have a purity of 90% or more, more preferably 95% or more, and further preferably 97% or more. The content ratio of the calcium oxide particles in the calcium hydroxide particles 1a is preferably 1% by mass or less.

The average particle size of the calcium hydroxide particles 1a is preferably 0.1 μm or more and 20 μm or less, more preferably 0.5 μm or more and 10 μm or less, and further preferably 1 μm or more and 5 μm or less.
The average particle size of the calcium hydroxide particles 1a is measured according to JIS Z8825 using a laser diffraction type particle size distribution measuring machine (SALD-2300 manufactured by Shimadzu Corporation) as a measuring device before compounding. As a specific measurement method, calcium hydroxide particles are dispersed in a water tank, the diffraction / scattering intensity distribution of light is measured and analyzed using the above device, and the particle size and volume-based particle size distribution are measured. It is calculated by doing. The measurement method, measurement range, and light source are as follows.
・ Measurement method: Laser diffraction and scattering ・ Measurement range: 0.017 to 2500 μm
-Light source: Semiconductor laser (wavelength 680 nm, output 3 mW)

The first resin layer 1 preferably contains an erucic acid amide. By containing the erucic acid amide in the first resin layer 1, it is possible to further suppress the loss of calcium hydroxide particles. As a result, when the film is made into a bag, the appearance of the fresh food contained therein can be suppressed from changing with time, and bacteria such as Escherichia coli can be suppressed from increasing with time.
When the first resin layer 1 contains an erucic acid amide, the content thereof is preferably 0.01% by mass or more and 1% by mass or less, and 0.02% by mass or more, based on the first resin composition. It is more preferably 0.2% by mass or less, further preferably 0.03% by mass or more and 0.1% by mass or less, and particularly preferably 0.03% by mass or more and 0.07% by mass or less. ..

The first resin layer 1 preferably contains calcium stearate. Since the first resin layer 1 contains calcium stearate, it is possible to further prevent the calcium hydroxide particles from falling off, and the opening property when the bag body is formed becomes better.
When the first resin layer 1 contains calcium stearate, the content thereof is preferably 0.01% by mass or more and 1% by mass or less, and 0.02% by mass or more and 0 by mass, based on the first resin composition. It is more preferably 2% by mass or less, further preferably 0.02% by mass or more and 0.1% by mass or less, and particularly preferably 0.02% by mass or more and 0.07% by mass or less.

The first resin layer 1 preferably contains both erucic acid amide and calcium stearate. Since the first resin layer 1 contains both erucic acid amide and calcium stearate, the effect of suppressing the shedding of calcium hydroxide particles is further exhibited. When the first resin layer 1 contains both erucic acid amide and calcium stearate, the preferable range of the content is the same as the above-mentioned preferable range.

The first resin layer 1 may contain additives other than calcium hydroxide particles, erucic acid amide, and calcium stearate. Examples of such additives include antistatic agents, antioxidants, antiblocking agents and the like. When the first resin layer 1 contains the additive, the content thereof is preferably 1% by mass or less based on, for example, the first resin composition.

The second resin layer 2 is composed of a second resin composition containing the second resin (hereinafter, also simply referred to as a second resin composition). The second resin contains a polyolefin-based homopolymer. The second resin layer 2 preferably contains 80% by mass or more of the polyolefin-based homopolymer, and more preferably 90% by mass or more, based on the second resin composition.
The second resin may be entirely a polyolefin-based homopolymer, or may contain other resins. Examples of other resins include crystalline polyolefin resins. As the crystalline polyolefin resin, ethylene, propylene, 1-butene, 1-pentene, 3-methyl-1-pentene, 4-methyl-1-pentene, 1-hexene, 1-octene and the like are used as monomers. Examples thereof include a homopolymer and a binary copolymer, and these can be used alone or in combination of two or more.

As the polyolefin-based homopolymers, low-density polyethylene (LDPE) homopolymers, medium-density polyethylene (MDPE) homopolymers, high-density polyethylene (HDPE) homopolymers, biaxially stretched polypropylene (OPP) homopolymers, and non-stretched homopolymers. Examples include homopolymers of polypropylene (CPP). Low-density polyethylene homopolymers are linear low-density polyethylene (LLDPE) homopolymers, metallocene linear low-density polyethylene homopolymers, metallocene low-density polyethylene homopolymers, or ultra-low-density polyethylene homopolymers. May be good.

The thickness of the second resin layer 2 is preferably more than 10 μm, more preferably 12 μm or more and 60 μm or less, further preferably 15 μm or more and 40 μm or less, and particularly preferably 20 μm or more and 30 μm or less. preferable.
Further, the thickness of the second resin layer 2 is preferably 1/3 or more of the thickness of the entire film according to the present embodiment.
The thickness of the second resin layer 2 can be measured in the same manner as the thickness of the first resin layer 1 described above.

The second resin layer 2 may contain other additives. Examples of such additives include antistatic agents, antioxidants, antiblocking agents and the like. When the second resin layer 2 contains the additive, the content thereof is preferably 1% by mass or less based on, for example, the second resin composition.

The third resin layer 3 is composed of a third resin composition containing the third resin (hereinafter, simply referred to as a third resin composition). The third resin contains an ethylene-propylene-butene ternary copolymer. The third resin layer 3 preferably contains 70% by mass or more of the ethylene-propylene-butene ternary copolymer, and more preferably 80% by mass or more, based on the third resin composition.
The third resin may be an ethylene-propylene-butene ternary copolymer, or may contain other resins. Examples of other resins include crystalline polyolefin resins. As the crystalline polyolefin resin, ethylene, propylene, 1-butene, 1-pentene, 3-methyl-1-pentene, 4-methyl-1-pentene, 1-hexene, 1-octene and the like are used as monomers. Examples thereof include a homopolymer and a binary copolymer, and these can be used alone or in combination of two or more.

The thickness of the third resin layer 3 is preferably 0.01 μm or more and 10 μm or less, more preferably 0.1 μm or more and 3 μm or less, and further preferably 0.5 μm or more and 1 μm or less.
The thickness of the third resin layer 3 can be measured in the same manner as the thickness of the first resin layer 1 described above.

The third resin layer 3 may contain additives such as erucic acid amide, calcium stearate, antistatic agent, antioxidant, and antiblocking agent. When the third resin layer 3 contains the additive, the content thereof is preferably 1% by mass or less with respect to, for example, the third resin composition.

The structure of the food packaging film 10 having the second resin layer 2 as the central layer and having the first resin layer 1 and the third resin layer 3 on the surfaces facing each other of the second resin layer 2 as the central layer, that is, In the case of the three-layer structure, the total thickness of the food packaging film 10 is preferably more than 10 μm and 80 μm or less, more preferably 16 μm or more and 46 μm or less, and further preferably 23 μm or more and 33 μm or less.

(Food packaging bag)
The food packaging bag 100 according to the present embodiment is made of a food packaging film 10. In the food packaging bag 100 according to the present embodiment, the inner surface of the bag is composed of the first resin layer 1.
The food packaging bag 100 according to the present embodiment is, for example, as shown in FIGS. 2A and 2B, a food packaging folded from a substantially central portion so that one surface 11 and the other surface 12 overlap each other. The film 10 is formed by sealing the edge portions 14 and 15 extending in a direction orthogonal to the folding line 13 formed when the film 10 is folded.

Generally, the bag body made of a resin film is produced by heat-sealing the edge portions 14 and 15 extending in the direction orthogonal to the folding line 13 as described above.
Therefore, the resin layer constituting the inner surface of the bag (the first resin layer 1 in the food packaging bag 100 according to the present embodiment) preferably contains a resin having a relatively low melting point, and such a resin is used. Usually, a copolymer of an olefin resin is used.
Since the resin film as described above is usually stretch-molded, when the outermost layer of the resin film contains calcium hydroxide particles, the resin and the calcium hydroxide particles constituting the outermost layer are formed during the stretch-molding of the resin film. It is considered that a void is formed between the void and the void, and the void remains in the formed resin film.
Further, when a resin film containing an ethylene-propylene-butene ternary copolymer and a resin film containing a random copolymer are stretch-molded at the same temperature, the melting point of the ethylene-propylene-butene ternary polymer is generally higher. Is lower than the melting point of the random copolymer, so that the interfacial adhesion with the calcium hydroxide particles is high, and it is considered that voids are less likely to be formed during stretch molding.
As described above, the food packaging bag 100 according to the present embodiment has an external force (for example, a food packaging film) applied when the food packaging bag 100 is produced from the food packaging film 10 because the number of voids formed is small. It is considered that the calcium hydroxide particles 1a are less likely to be affected by the external force applied to the food packaging film 10 during the transportation of the 10 and the sealing of the food packaging film 10.
As a result, the present inventor presumes that in the food packaging bag 100 according to the present embodiment, the calcium hydroxide particles 1a are less likely to fall off from the first resin layer 1.

(Manufacturing method of food packaging film)
The food packaging film 10 according to the present embodiment constitutes the first resin composition constituting the first resin layer 1, the second resin composition constituting the second resin layer 2, and the third resin layer 3. It can be produced by coextruding the third resin composition.
Examples of such coextrusion molding include a coextrusion multilayer T-die method, and examples of the coextrusion multilayer T-die method include a feed block method and a multi-manifold method. The coextrusion multilayer T-die method can be performed using various known coextrusion multilayer molding devices.
The food packaging film 10 according to the present embodiment may be co-extruded and then stretch-molded. The stretch molding is preferably biaxial stretching molding. When the stretching molding is performed by biaxial stretching molding, the stretching in the MD direction is preferably performed at a temperature of 100 to 140 ° C. and a stretching ratio of 3 to 6 times, and the stretching in the TD direction is performed at a temperature of 130 to 160 ° C. and a stretching ratio of 8. It is preferable to carry out at ~ 12 times.

The first resin includes a melted resin pellet obtained by molding a resin containing an ethylene-propylene-butene ternary copolymer as a main component into a pellet shape (hereinafter referred to as a ternary polymer resin pellet), and a predetermined amount. A resin containing calcium hydroxide particles (for example, a propylene-ethylene copolymer) formed into pellets and melted resin pellets can be used. Examples of the ternary copolymer resin pellets include FL6741 manufactured by Sumitomo Chemical Co., Ltd. and 5C37F manufactured by Basel. The ternary copolymer resin pellets may be used alone or in combination of two or more.
As the second resin, a resin obtained by melting resin pellets obtained by molding a resin containing homopolypropylene as a main component into pellets (hereinafter referred to as homopolymer resin pellets) can be used. Examples of the homopolymer resin pellets include F-300SP manufactured by Prime Polymer Co., Ltd. and E-200GP manufactured by Prime Polymer Co., Ltd. The homopolymer resin pellets may be used alone or in combination of two or more.
As the third resin, a resin obtained by melting resin pellets obtained by molding a resin containing an ethylene-propylene-butene ternary copolymer as a main component into pellets can be used. Examples of the ternary copolymer resin pellet include those described above. The ternary copolymer resin pellets may be used alone or in combination of two or more.
The temperature at which the first to third resin pellets are melted is preferably 200 to 300 ° C.

(Manufacturing method of food packaging bag)
The food packaging bag 100 according to the present embodiment is for food packaging, in which the food packaging film 10 is folded from a substantially central portion so that one surface and the other surface overlap each other, and is orthogonal to the folding line formed when the film 10 is folded. It can be manufactured by sealing the both end edge portions (edge edges 14, 15) of the film 10. Sealing (sealing) of both end edges of the food packaging film 10 can be performed by heat sealing.

The food packaging film 10 and the food packaging bag 100 according to the present invention are not limited to the above embodiments. Further, the food packaging film 10 and the food packaging bag 100 according to the present invention can be variously modified without departing from the gist of the present invention.

Next, the present invention will be described in more detail with reference to Examples and Comparative Examples. The present invention is not limited to the following examples as long as the gist of the present invention is not exceeded.

<Preparation of Food Packaging Films According to Examples 1 and 2>
Using the raw materials shown in Tables 1 and 2 below, the food packaging films according to Examples 1 and 2 were prepared, which consisted of a first resin layer, a second resin layer, and a third resin layer.
As the ethylene-propylene-butene ternary copolymer in the first resin layer and the third resin layer, a resin pellet 5C37F manufactured by Basel Co., Ltd. having an MFR of 5.5 g / 10 min and an MFR of 6.0 g / 10 min. The resin pellet FL6741G manufactured by Sumitomo Chemical Co., Ltd. was used.
As the homopolypropylene in the second resin layer, a resin pellet F-300SP manufactured by Prime Polymer Co., Ltd. and a resin pellet E-200GP manufactured by Prime Polymer Co., Ltd. were used.
In Examples 1 and 2, the resin pellet 5C37F and the resin pellet FL6741G were used in a mass ratio of 5C37F: FL6741G = 60: 40. Further, the resin pellet F-300SP and the resin pellet E-200GP were used in a mass ratio of F-300SP: E-200GP = 70: 30.
The calcium hydroxide particles were placed in a propylene-ethylene copolymer to prepare a calcium hydroxide-containing masterbatch. This masterbatch was contained in the mixture of the resin pellets 5C37F and FL6741G. Additives other than calcium hydroxide particles (calcium stearate, erucic acid amide, and other additives) are added to at least one of the above resin pellets 5C37F, FL6741G, F-300SP, and E-200GP. include.
The average particle size of the calcium hydroxide particles was 2.7 μm. As the calcium hydroxide particles, calcium hydroxide particles (calcium hydroxide particles derived from scallop shells) obtained by firing scallop shells at 1100 ° C. or higher and then digesting them were used. The average particle size of the calcium hydroxide particles was measured by the method described in the section of the above embodiment. The purity of the calcium hydroxide particles was 95% or more.

The food packaging films according to Examples 1 and 2 are biaxially stretch-molded after co-extruding the first resin composition, the second resin composition, and the third resin composition by a co-extrusion multilayer T-die method. It was produced by The co-extrusion multi-layer T-die method was performed using a co-extrusion multi-layer device equipped with three single-screw screw type extruders. The extrusion amount of the first resin composition, the extrusion amount of the second resin composition, and the extrusion amount of the third resin composition are the mass ratios of 1: 2: 3 = 1: 8.6: 0. It was set to 4.
The first resin composition was obtained by melting the resin pellet 5C37F (melting point 132 ° C.), the resin pellet FL6741G (melting point 130 ° C.), and the calcium hydroxide-containing masterbatch at 250 ° C.
The second resin composition was obtained by melting the resin pellet F-300SP and the resin pellet E-200GP at 250 ° C.
Further, the third resin composition was obtained by melting the resin pellets 5C37F and the resin pellet FL6741G at 250 ° C.
In the biaxial stretching molding, stretching in the MD direction was performed by stretching 4.6 times at a temperature of 123 ° C., and stretching in the TD direction was performed by stretching 10 times at a temperature of 151 ° C.
In the food packaging film according to Example 1, the thickness of the first resin layer is 1.8 μm, the thickness of the second resin layer is 25.5 μm, and the thickness of the third resin layer is 0.7 μm. The total thickness was 28 μm.
Further, in the food packaging film according to Example 2, the thickness of the first resin layer is 2.5 μm, the thickness of the second resin layer is 24.0 μm, and the thickness of the third resin layer is 0. It was 0.7 μm and the total thickness was 27.2 μm.

<Production of a film for food packaging according to Comparative Example 1>
Using the raw materials shown in Table 3 below, a food packaging film according to Comparative Example 1 was prepared, which was composed of a first resin layer, a second resin layer, and a third resin layer.
Incidentally, the propylene in the first resin layer and the third resin layer - as ethylene copolymer, using Japan Polypropylene Corp. resin pellets WFW5T (mp 142 ° C.).
As the homopolypropylene in the second resin layer, a resin pellet F-300SP manufactured by Prime Polymer Co., Ltd. and a resin pellet E-200GP manufactured by Prime Polymer Co., Ltd. were used.
The calcium hydroxide particles were placed in a propylene-ethylene copolymer to prepare a calcium hydroxide-containing masterbatch. This masterbatch was contained in the resin pellet WFW5T. Additives other than calcium hydroxide particles (calcium stearate, erucic acid amide, and other additives) are contained in at least one of the above-mentioned resin pellets WFW5T, F-300SP, and E-200GP. ing.
In Comparative Example 1, the resin pellet F-300SP and the resin pellet E-200GP were used in a mass ratio of F-300SP: E-200GP = 70: 30.

The food packaging film according to Comparative Example 1 is obtained by co-extruding the first resin composition, the second resin composition, and the third resin composition by a co-extrusion multilayer T-die method, and then biaxially stretching and molding. Made by The co-extrusion multi-layer T-die method was performed using a co-extrusion multi-layer device equipped with three single-screw screw type extruders. The extrusion amount of the first resin composition, the extrusion amount of the second resin composition, and the extrusion amount of the third resin composition are the mass ratios of 1: 2: 3 = 1: 8.6: 0. It was set to 4.
The first resin composition was obtained by melting the resin pellet WFW5T and the calcium hydroxide-containing masterbatch at 250 ° C.
The second resin composition was obtained by melting the resin pellet F-300SP and the resin pellet E-200GP at 250 ° C.
Further, the third resin composition was obtained by melting the resin pellet WFW5T at 250 ° C.
In the biaxial stretching molding, stretching in the MD direction was performed by stretching 4.6 times at a temperature of 123 ° C., and stretching in the TD direction was performed by stretching 10 times at a temperature of 151 ° C.
In the food packaging film according to Comparative Example 1, the thickness of the first resin layer is 1.8 μm, the thickness of the second resin layer is 25.5 μm, and the thickness of the third resin layer is 0.7 μm. The total thickness was 28 μm.

<Evaluation of dropout of calcium hydroxide particles from food packaging film>
Food packaging according to each example using a light interference type non-contact surface shape measuring device (Non-contact surface / layer cross-sectional shape measuring system manufactured by Ryoka System Co., Ltd., VertScan (registered trademark) 2.0 (model: R5500GML)) The surface of the first resin layer of the film was evaluated.
The surface of the first resin layer is evaluated by observing the surface of the first resin layer before and after the scratch test and measuring the height and sharpness of the convex portion on the surface of the first resin layer before and after the scratch test. went. The measurement points of the "convex height and sharpness on the surface of the first resin layer" before the scratch test are the measurement points of the "convex height and sharpness on the surface of the first resin layer" after the scratch test. Are the same.
The scratch test was carried out by scratching the surface of the first resin layer of the food packaging film according to each example with a paper waste (manufactured by Oji Nepia, product name "public paper waste") 60 times.

The optical interference type non-contact surface shape measuring instrument was operated under the following conditions.

-Measurement mode: WAVE
-Filter: 530 white
・ Objective lens magnification: × 10
-Field of view: 470.92 μm × 353.16 μm (640 × 480 pixel)

The following image processing was performed on the data measured by the optical interference type non-contact surface shape measuring device using the analysis software "VS-Viewer".

-Surface correction: Polynomial approximation 4th order-Interpolation: Complete-Noise removal processing: Median filter (3 x 3 pixels)

Zoom display and cross-sectional observation were performed on any convex portion in the first resin layer of the food packaging film according to each example before and after the scratch test, and the height and sharpness of the convex portion were evaluated.
The height and sharpness of the convex portion were evaluated as follows.

(1) Observe the surface of the first resin layer of the food packaging film according to each example, and measure the height and sharpness of the convex portion of the calcium hydroxide particles for the food packaging film according to each example.
(2) Observe the surface of the first resin layer of the food packaging film according to each example, and search for a convex portion having an approximate shape.
(3) A scratch test is performed on the surface of the first resin layer of the food packaging film according to each example, and the height and sharpness of the convex portion are compared before and after the test.

In the scratch test, the food packaging film is used as a food packaging bag so that the first resin layer constitutes the inner surface of the bag, and then the food packaging bag contains fresh foods such as vegetables. In the meantime, the inner surfaces of the food packaging bag rub against each other.
The images of the surface of the first resin layer of the food packaging film according to Example 1 and Comparative Example 1 before and after the scratch test are shown in FIG.
The results of measuring the height and sharpness of the convex portion after the scratch test are shown in Table 4 below.

Comparing FIG. 3 (a) and FIG. 3 (b), it was found that no shedding of calcium hydroxide particles was observed from the first resin layer of the food packaging film according to Example 1 (in the figure). See the circled area).
On the other hand, when FIG. 3 (c) and FIG. 3 (d) were compared, it was found that the calcium hydroxide particles were shed from the first resin layer of the freshness-preserving film according to Comparative Example 1 (FIG. 3). See the circled area).
From this result, it was confirmed that the loss of calcium hydroxide particles from the first resin layer was suppressed by including the ethylene-propylene-butene ternary copolymer in the first resin layer.

Further, according to Table 4, in the first resin layer of the food packaging film according to Examples 1 and 2, a significant difference was observed in the height and sharpness of the convex portion of the first resin layer before and after the scratch test. There wasn't. That is, it was confirmed that the shedding of calcium hydroxide particles from the first resin layer was suppressed.
On the other hand, in the first resin layer of the food packaging film according to Comparative Example 1, it was confirmed that the height of the convex portion was significantly reduced after the scratch test. That is, it was confirmed that the height of the convex portion was greatly reduced due to the calcium hydroxide particles falling off from the first resin layer.

As a result, by using the food packaging film according to the present invention to prepare a food packaging bag so that the inner surface of the bag is composed of the first resin layer, the contained fresh food (vegetables, fruits, fresh fish). , Meat, etc., especially vegetables and fruits) can be sufficiently maintained, and the dropped calcium hydroxide is mixed in the contained fresh food (vegetables, fruits, fresh fish, meat, etc., especially vegetables and fruits). It can be expected that it can be suppressed.

<Evaluation of freshness retention function of food packaging bags>
Using the food packaging film according to Example 1, five food packaging bags according to Example 1 were prepared so that the inner surface of the bag was composed of the first resin layer. Specifically, as shown in FIG. 2, in the food packaging film 10 folded from the substantially central portion so that the one surface 11 and the other surface 12 overlap each other, the folding line 13 formed when the film 10 is folded. By sealing the edge portions 14 and 15 extending in the orthogonal direction, five food packaging bags according to Example 1 were produced.
Further, using the food packaging film according to Example 2, five food packaging bags according to Example 2 were produced in the same manner as described above.
Further, as the food packaging bag according to Comparative Example 2, five food packaging bags made by using an OPP film (biaxially stretched polypropylene film) were prepared. The food packaging bag did not contain calcium hydroxide particles.

After storing the cut vegetables (lettuce) in each of the food packaging bags according to Examples 1 and 2 and the food packaging bags according to Comparative Example 2 produced in groups of 5 as described above, each food product is used. The open end of the packaging bag was sealed.
Then, these food packaging bags are opened one by one over time, and the appearance of Escherichia coli and cut vegetables (lettuce) changes with time (D + 0, D + 2, D + 3, D + 4, and D + 5. Here, D. Is the day when the cut vegetables were housed).
The number of E. coli is described in "Food Hygiene Inspection Guideline Microorganisms Edition 2004, 2nd print issued on July 1, 2005, Japan Food Hygiene Association". 129-P. It was measured by the method described in 145. Specifically, (i) sampling, (ii) preparation of sample solution, (iii) inoculation of sample solution, (iv) primary enrichment culture, (v) secondary enrichment culture, (vi) stroke separation. Culturing, (vii) differential identification, and (vii) result determination were performed in this order.
In the sampling of (i), 25 g of the sample is weighed and transferred to a sterile plastic bag, and in the preparation of the sample solution of (ii), 225 ml of sterile diluted water corresponding to 9 times the amount is added and homogenized for 30 seconds. The sample was used as the sample stock solution, and was diluted 10-fold with sterile diluted water. Inoculate the fermentation tube, and in the primary enrichment culture of (iv), the bouillon fermentation tube inoculated with the sample is cultured at 35 ± 1 ° C. for 48 hours, and in the secondary enrichment culture of (v), bouillon fermentation. 1 Platinum ear of the culture solution in the tube was inoculated into an EC medium fermentation tube and cultured in a constant temperature water bath at 44.5 ± 0.2 ° C. for 24 hours. In the line-separated culture of (vi), EMB agar The cells were smear-cultured on a medium plate and cultured at 35 ± 1 ° C. for 24 hours, and in the differential identification of (vii), the number of sample-inoculated fermentation tubes in which the presence of Escherichia coli was confirmed was calculated. As the diluted water, 0.1% peptone-added physiological saline was used.

Changes in the appearance of cut vegetables over time were evaluated according to the following criteria.
・ A: No change in appearance ・ B: Slight discoloration to red is observed but no problem ・ C: Slight discoloration to brown is observed but no problem ・ D: Discoloration from red to brown is conspicuous and problematic ・ E : Discoloration to brown is conspicuous, there is a problem

The results of investigating changes in the appearance of Escherichia coli and cut vegetables (lettuce) over time are shown in Table 5 below.

From Table 5, it can be seen that the food packaging bags according to Examples 1 and 2 are significantly improved in the time course of the appearance of the cut vegetables (lettuce) as compared with the food packaging bags according to Comparative Example 2. Do you get it.
Further, in the food packaging bags according to Examples 1 and 2, no change with time of Escherichia coli was observed. From this, it was found that the food packaging bags according to Examples 1 and 2 are excellent in the function of maintaining the freshness of food.

In addition, the general viable cell count of the food packaging bag according to Examples 1 and 2 was also evaluated. The general viable cell count is the Food Hygiene Inspection Guideline Microorganisms Edition 2004, July 1, 2005, 2nd print, Japan Food Hygiene Association 129-P. It was measured by the method described in 145.
Specifically, (i) sampling, (ii) preparation of sample solution, (iii) preparation of mixed plate, (iv) culture of mixed plate, (v) measurement of appearance settlement, (vi) viable bacteria The number was calculated in order.
In the sample collection of (i), 25 g of the sample is weighed and transferred to a sterile plastic bag, and in the preparation of the sample solution of (ii), 225 ml of sterile diluted water corresponding to a 9-fold amount is added and homogenized for 30 seconds. The sample was used as the sample stock solution, and diluted 10-fold with sterile diluted water. In the preparation of the pour plate of (iii), 1 ml of each diluted sample solution was dispensed, and then about 15 ml of the standard agar medium was sterile. Pour into each Petri dish immediately, and gently mix the sample and medium so that they mix well. In the culture on the mixed flat ground in (iv), when the agar medium has completely solidified, the Petri dish is inverted and 35 ± After culturing at 1 ° C. for 48 hours, the colony counter was used to measure the appearance colonies of (v), and the viable cell count of (vi) was diluted with the number of flat colonies used for calculation. , And the upper 3 digits of the obtained number were rounded off, the upper 2 digits were displayed as valid numbers, and 0 was added below to obtain the number of bacteria per 1 g of food. As the diluted water, 0.1% peptone-added physiological saline was used.

As a result, the retention period D + 0 day, the food packaging bag according to the first embodiment, a total viable count is 6.0 × 10 ^2, in the food packaging bag according to the second embodiment, the total viable count a 7.0 × 10 ^2, in the food packaging bag of Comparative example 2, total viable count was 2.4 × 10 ^4. That is, it was found that the food packaging bags according to Examples 1 and 2 had a smaller general viable cell count than the food packaging bags according to Comparative Example 2.
Further, total viable count for food packaging bag according to Examples 1 and 2, the retention period D + 2 days, respectively, 1.2 × ¹⁰ 4, a 1.4 × 10 ^4, the retention period D + 3 days, respectively 1.4 × ¹⁰ 5, a 2.3 × 10 ^4, the retention period D + 4 days, respectively, 1.5 × ¹⁰ 5, a 7.3 × 10 ^4, the retention period D + 5, respectively, 4 .5 × ¹⁰ 5, of 2.5 × 10 ^5.
From these results, it was found that the food packaging bags according to Examples 1 and 2 have a function of maintaining the freshness of food from the viewpoint of the general viable cell count.

Furthermore, the number of coliform bacteria in the food packaging bags according to Examples 1 and 2 was also evaluated. The number of coliform bacteria is shown in the Food Hygiene Inspection Guideline, Microorganisms, 2004, July 1, 2005, 2nd print, Japan Food Hygiene Association. 129-P. It was measured by the method described in 145.
Specifically, (i) sampling, (ii) preparation of sample solution, (iii) inoculation of sample solution, (iv) enrichment culture, (v) striation separation culture, (vi) differential identification, (vii) ) Result judgment was performed in order.
In the sample collection of (i), 25 g of the sample is weighed and transferred to a sterile plastic bag, and in the preparation of the sample solution of (ii), 225 ml of sterile diluted water corresponding to 9 times the amount is added and homogenized for 30 seconds. The sample stock solution was used as the sample stock solution, and the sample solution was diluted 10-fold with sterile diluted water. In the inoculation of the sample solution (iii), 10 ml of the sample stock solution, 1 ml, and 1 ml of the 10-fold step-diluted solution were used in 5 bouillons. The fermenter was inoculated, and in the enrichment culture of (iv), the bouillon fermenter inoculated with the sample was cultured at 35 ± 1.0 ° C. for 48 hours, and in the line-separated culture of (v), EMB agar. It was smear-cultured on a medium plate and cultured at 35 ± 1 ° C. for 24 hours, and in the differential identification of (vi), it was calculated from the number of sample-inoculated fermentation tubes in which the presence of Escherichia coli was observed (MPN calculation method). As the diluted water, 0.1% peptone-added physiological saline was used.

As a result, the retention period D + 0 day, the food packaging bag according to the first embodiment, a coliform count 1.0 × 10 ^1, in the food packaging bag according to the second embodiment, the number of E. coli group 5. 0 a × 10 ^1, in the food packaging bag of Comparative example 2, number of E. coli group was 6.7 × 10 ^2. That is, it was found that the food packaging bags according to Examples 1 and 2 had a smaller number of coliform bacteria than the food packaging bags according to Comparative Example 2.
Furthermore, E. coli group count for food packaging bag according to Examples 1 and 2, the retention period D + 2, respectively, 1.1 × ¹⁰ 2, a 3.6 × 10 ^2, the retention period D + 3, respectively, 5 It is .8 × 10 ¹ and 1.2 × 10 ¹ , and it is 9.2 × 10 ¹ and 4.7 × 10 ¹ in the storage days D + 4, respectively, and 1.4 × 10 in the storage days D + 5, respectively. ^5, was 2.0 × 10 ^4.
From these results, it was found that the food packaging bags according to Examples 1 and 2 have a function of maintaining the freshness of food from the viewpoint of the number of coliform bacteria.

1: 1st resin layer 2: 2nd resin layer 3: 3rd resin layer 10: Food packaging film, 11: One side, 12: The other side, 13: Folding line, 14: Edge part, 15 : Edge part, 100: Food packaging bag,
1a: Calcium hydroxide particles.

Claims (8)

A first resin layer containing the first resin and calcium hydroxide particles is provided as the outermost layer.
The first resin is a film for food packaging containing an ethylene-propylene-butene ternary copolymer. The food packaging film according to claim 1, wherein the thickness of the first resin layer is 0.01 μm or more and 10 μm or less. Further provided with a second resin layer containing a second resin,
The second resin layer is laminated on one surface of the first resin layer.
The food packaging film according to claim 1 or 2, wherein the thickness of the second resin layer exceeds 10 μm. The food packaging film according to claim 3, wherein the second resin contains a polyolefin-based homopolymer. Further provided with a third resin layer containing a third resin,
The third resin layer is laminated on the other surface of the first resin layer facing the one surface.
The food packaging film according to claim 3 or 4, wherein the thickness of the third resin layer is 0.01 μm or more and 10 μm or less. The food packaging film according to claim 5, wherein the third resin contains an ethylene-propylene-butene ternary copolymer. The first resin layer according to any one of claims 1 to 6, which contains 0.1% by mass or more and 12% by mass or less of calcium hydroxide particles with respect to the first resin composition containing the first resin. The described food packaging film. A food packaging bag made of the food packaging film according to any one of claims 1 to 7.
A food packaging bag in which the inner surface of the bag is composed of the first resin layer.