Patent Application
20240269975
The present invention relates to a packaging material film, a packaging material, a packaging bag, and a package body.
A package body in which an oil-in-water dispersion-type content such as curry is enclosed is known. In such a package body, problems have been pointed out, for example, as follows: when the package body is opened and the content is discharged, the whole content cannot be used up to cause wastefulness, adhesion of the content causes contamination, and it takes a lot of trouble with a discharge operation of the content.
Therefore, the package body is required to allow the content to slip down easily when the package body is opened, that is, to impart excellent slip-down property to the content.
For example, in Patent Literature 1, it is proposed that, by a package body using a packaging sheet, which includes a heat seal layer containing polyolefin-based particles with an average particle diameter D50 of 10 to 50 μm and a melting point of 100° C. to 180° C. and having a surface roughness Ra of 1.00 to 7.00 μm, a content is less likely to adhere to the surface and is easily discharged from the package body.
However, the package body described in Patent Literature 1 described above has the following problems.
That is, the package body described in Patent Literature 1 described above has room for improvement in terms of easiness of discharging the content when the package body is opened, that is, slip-down property.
The present invention has been made in view of the above circumstances, and an object thereof is to provide a packaging material film capable of imparting excellent slip-down property to an oil-in-water dispersion-type content by a heating treatment, and a packaging material, a packaging bag, and a package body that include the packaging material film. Note that, in the present invention, the oil-in-water dispersion-type content means a content which contains water and lipid and in which the contained amount of water is larger than the contained amount of lipid. The “lipid” is a concept inclusive of oil that is in a liquid state at 20° C. (room temperature) and fat that is a solid at 20° C. Hereinafter, the above-described oil contained in the oil-in-water dispersion-type content and the above-described fat, which is liquefied by a heating treatment to which the packaging material film according to the present invention is subjected, are collectively referred to as “oil content”.
In order to solve the above problems, an aspect of the present invention (first invention) is a packaging material film including a first resin layer that contains a polyolefin resin and fillers, in which protrusions are formed on a surface of the first resin layer by the fillers, and a water sliding angle at room temperature of an oil film on the surface of the first resin layer as measured by the following measurement method is 20° or less.
According to this packaging material film, the polyolefin resin in the first resin layer can absorb the oil content and swell under the temperature conditions of the retort treatment or the boiling treatment. Therefore, when the packaging material film is used as a packaging material for a package body in which an oil-in-water dispersion-type content is enclosed and the heating treatment such as a retort treatment or a boiling treatment is performed in a state where the oil-in-water dispersion-type content is brought into contact with the surface of the first resin layer of the packaging material film, some of the oil content in the content is absorbed by the first resin layer. At this time, the water sliding angle at room temperature of the oil film on the surface of the first resin layer as measured by the above predetermined measurement method is 20° or less. That is, this means that the surface of the first resin layer on the side of the content has appropriate irregularities due to the fillers, the oil content contained in the content is absorbed by the first resin layer, and thus the lipophilicity of the first resin layer is improved. When the oil film exists on the surface of the first resin layer and the water sliding angle at room temperature of the oil film is 20° or less, the content is prevented from being in direct contact with the surface of the first resin layer, and the content whose surface portion is configured by water is likely to be slippery with the oil film having water repellency as an interface. Therefore, the packaging material film of the present invention can impart excellent slip-down property to the oil-in-water dispersion-type content by the heating treatment.
In the packaging material film of the first invention, an amount of the oil film to be formed is preferably 0.2 to 1.2 g/200 cm2. When the amount of the oil film is within the above range, favorable slip-down property with respect to the content is easily maintained.
Another aspect of the present invention (second invention) for solving the above problems is a packaging material film including a first resin layer that contains a polyolefin resin and fillers, in which a ratio Y/X of a surface area ratio Y of a surface of the first resin layer with respect to an arithmetic mean height Sa X μm of the surface of the first resin layer is 0.4 to 8.0 μm−1.
According to this packaging material film, the polyolefin resin in the first resin layer can absorb the oil content and swell under the temperature conditions of the retort treatment or the boiling treatment. Therefore, when the packaging material film is used as a packaging material for a package body in which an oil-in-water dispersion-type content is enclosed and the heating treatment such as a retort treatment or a boiling treatment is performed in a state where the oil-in-water dispersion-type content is brought into contact with the surface of the first resin layer of the packaging material film, some of the oil content in the content is absorbed by the first resin layer. At this time, in the first resin layer, since a ratio Y/X of a surface area ratio Y of a surface S of a first resin layer 21 with respect to an arithmetic mean height Sa X μm of the surface of the first resin layer is 0.4 to 8.0 μm−1, the surface of the first resin layer on the side of the content can have appropriate irregularities due to the fillers, and a contact area between the first resin layer and the oil-in-water dispersion-type content becomes larger. Therefore, the oil content contained in the content is easily absorbed by the first resin layer, and the lipophilicity of the first resin layer is improved. This facilitates the stable formation of an oil film between the surface of the first resin layer and the content. Since the oil film is interposed between the surface of the first resin layer and the content, the content is prevented from being in direct contact with the surface of the first resin layer, and the content whose surface portion is configured by water is likely to be slippery with the oil film having water repellency as an interface. Therefore, the packaging material film of the present invention can impart excellent slip-down property to the oil-in-water dispersion-type content by the heating treatment.
In the packaging material film of the second invention, a projected area ratio of protrusions formed by the fillers on the surface of the first resin layer is preferably 8 to 45%. When the projected area ratio is within the above range, favorable slip-down property with respect to the content is easily maintained.
In the packaging material film, the fillers preferably include a porous filler. By using a porous filler, an oil film is easy to be more stably formed between the surface of the first resin layer and the content, and further excellent slip-down property with respect to the content is likely to be exhibited.
In the packaging material film, the first resin layer preferably further contains an elastomer component. Thereby, further excellent slip-down property with respect to the content is likely to be exhibited.
Furthermore, still another aspect of the present invention is a packaging material including a substrate and a packaging material film provided on the substrate, in which the packaging material film is composed of the aforementioned packaging material film, and a surface of the first resin layer of the packaging material film on a side opposite to the substrate is exposed.
This packaging material includes the above-described packaging material film, and the packaging material film is subjected to a heating treatment in a state where the oil-in-water dispersion-type content is brought into contact with the exposed surface on a side opposite to the substrate, so that excellent slip-down property can be imparted to the oil-in-water dispersion-type content. Furthermore, since this packaging material further includes a substrate, the packaging material film is reinforced by the substrate.
Still another aspect of the present invention is a packaging bag for containing an oil-in-water dispersion-type content, the packaging bag being formed using the aforementioned packaging material, the first resin layer being disposed on an inner side thereof.
According to this packaging bag, the packaging material film included in the packaging material is subjected to a heating treatment, so that excellent slip-down property can be imparted to the oil-in-water dispersion-type content that comes into contact with the first resin layer. Therefore, after the oil-in-water dispersion-type content is enclosed in the packaging bag to obtain a package body, when the package body is subjected to the heating treatment such as a retort treatment or a boiling treatment, the oil-in-water dispersion-type content can be easily slipped down at the time of discharging the oil-in-water dispersion-type content from the package body after the package body is opened. Thus, the residual liquid amount of the oil-in-water dispersion-type content can be reduced, waste of the content can be prevented, contamination due to adhesion of the content can be prevented, and a discharge operation of the content can be efficiently performed.
Still another aspect of the present invention is a package body including the aforementioned packaging bag and an oil-in-water dispersion-type content enclosed in the packaging bag.
According to this package body, the packaging material film included in the packaging material is subjected to a heating treatment, so that excellent slip-down property can be imparted to the oil-in-water dispersion-type content that comes into contact with the first resin layer. Therefore, when the package body is subjected to the heating treatment such as a retort treatment or a boiling treatment, the oil-in-water dispersion-type content can be easily slipped down at the time of discharging the oil-in-water dispersion-type content from the package body after the package body is opened. Thus, the residual liquid amount of the oil-in-water dispersion-type content can be reduced, waste of the content can be prevented, contamination due to adhesion of the content can be prevented, and a discharge operation of the content can be efficiently performed.
According to the present invention, there are provided a packaging material film capable of imparting excellent slip-down property to an oil-in-water dispersion-type content by a heating treatment, and a packaging material, a packaging bag, and a package body that include the packaging material film.
Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings. Note that, in the drawings, the same or equivalent constituent elements are designated by the same reference signs, and redundant description will be omitted. Furthermore, the dimensional ratios in the drawings are not limited to ratios illustrated in the drawings.
First, an embodiment of a packaging material of the present invention will be described with reference to
A packaging material 100 illustrated in
The packaging material 100 includes a substrate 10, a packaging material film 20 provided on the substrate 10, and an adhesive layer 30 attaching the substrate 10 and the packaging material film 20 to each other.
The packaging material film 20 includes a first resin layer 21 containing a polyolefin resin and fillers and a second resin layer 22, and in the packaging material film 20, the first resin layer 21 is disposed on a side opposite to the substrate 10 and the second resin layer 22 is disposed on the substrate 10 side. That is, a surface S of the first resin layer 21 on a side opposite to the substrate 10 is exposed. The surface S of this first resin layer 21 will be an inner surface of a packaging bag in a case where a packaging bag (for example, a retort pouch) is formed using the packaging material 100.
The first resin layer 21 contains a resin composition 21a containing a polyolefin resin and fillers 21b dispersed in the resin composition 21a. Protrusions are formed on the surface S of the first resin layer by the fillers 21b.
According to the packaging material 100, the polyolefin resin contained in the first resin layer 21 of the packaging material film 20 can absorb the oil content and swell under the temperature conditions of a retort treatment or a boiling treatment. Therefore, when the packaging material 100 is used as a package body in which an oil-in-water dispersion-type content C is enclosed, the oil-in-water dispersion-type content C is brought into contact with the surface S of the first resin layer 21 of the packaging material film 20 (see
At this time, in a first embodiment, a water sliding angle at room temperature of an oil film Fo on the surface S of the first resin layer 21 as measured by a measurement method described below is 20° or less. That is, this means that the surface of the first resin layer 21 on the side of the content C has appropriate irregularities due to the fillers 21b, the oil content Co contained in the content C is absorbed by the first resin layer 21, and thus the lipophilicity of the first resin layer 21 is improved.
By appropriately adjusting the degree of formation of the protrusions by the fillers 21b on the surface S of the first resin layer 21, the oil film Fo is easy to be stably formed between the surface S of the first resin layer 21 and the content C. Further, since the oil film Fo is interposed between the surface S of the first resin layer 21 and the content C, the water sliding angle can be set in a desired range, so that the content C is prevented from being in direct contact with the surface S of the first resin layer 21, and the content C whose surface portion is configured by water is likely to be slippery with the oil film Fo having water repellency as an interface.
Furthermore, at this time, in a second embodiment, in the first resin layer 21, since a ratio Y/X of a surface area ratio Y of the surface S of the first resin layer 21 with respect to an arithmetic mean height Sa X μm of the surface S of the first resin layer 21 is 0.4 to 8.0 μm−1, the surface S of the first resin layer 21 on the side of the content C can have appropriate irregularities due to the fillers 21b, and a contact area between the first resin layer 21 and the oil-in-water dispersion-type content C becomes larger. Therefore, the oil content Co contained in the content C is easily absorbed by the first resin layer 21, and the lipophilicity of the first resin layer 21 is improved. The inventors speculate that a large number of protruding structures of about several micrometers, which are produced by the fillers 21b, is important in the formation of the oil film Fo, and that this is a structure that cannot be obtained by a general processing method such as a shaping treatment.
Herein, Y/X is a three-dimensional parameter that expresses the efficiency with which the arithmetic mean height Sa contributes to the surface area ratio. The arithmetic mean height Sa is a parameter obtained by extending Ra (arithmetic mean height of lines) to a surface. The surface area ratio is a parameter that expresses the ratio of the actual surface area with respect to the area when a surface on which the surface shape is measured is assumed to be completely flat. In a case where the ratio Y/X of both the arithmetic mean height and the surface area ratio is within the above range, favorable slip-down property with respect to the content C can be attained. For example, even when the value of Sa is the same, it can be said that the larger the surface area ratio, the better the contribution efficiency to the slip-down property.
By appropriately adjusting the degree of roughness and surface area ratio of the surface S of the first resin layer 21, the oil film Fo is easy to be stably formed between the surface S of the first resin layer 21 and the content C. Further, since the oil film Fo is interposed between the surface S of the first resin layer 21 and the content C, the content C is prevented from being in direct contact with the surface S of the first resin layer 21, and the content C whose surface portion is configured by water is likely to be slippery with the oil film Fo having water repellency as an interface.
Therefore, in the first and second embodiments, as illustrated in
Furthermore, since the polyolefin resin has thermal adhesiveness, the first resin layer 21 can also play a role of a sealant film. Therefore, when a package body is formed, the package body can be easily formed using the packaging material 100 by heat-sealing the first resin layers 21 to each other with the first resin layers 21 facing inward.
Hereinafter, the first resin layer 21, the second resin layer 22, the substrate 10, and the adhesive layer 30 that constitute the packaging material 100 will be described.
The first resin layer 21 is a layer that imparts excellent slip-down property to the oil-in-water dispersion-type content C by subjecting the first resin layer to a heating treatment (for example, a retort treatment and a boiling treatment) in a state of being in contact with the oil-in-water dispersion-type content C.
The content percentage of the polyolefin resin in the resin composition 21a is usually 75% by mass or more, and may be 80% by mass or more or 90% by mass or more. The resin composition 21a may be substantially composed of a polyolefin resin.
Examples of the polyolefin resin include a polypropylene resin, a polyethylene resin, and a polybutylene resin. Among them, from the viewpoint of excellent heat resistance, a polypropylene resin is preferable.
Examples of the polyethylene resin include low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, high-density polyethylene, and an ethylene-α-olefin copolymer.
Examples of the polypropylene resin include a homopolypropylene, a block polypropylene, a random polypropylene, a propylene-α-olefin copolymer, and a modified polypropylene. In the case of using a combination of a block polypropylene and a random polypropylene as the polypropylene resin, the mass ratio of the block polypropylene and the random polypropylene (block polypropylene/random polypropylene) is preferably 20/80 to 80/20 and further preferably 40/60 to 60/40. Examples of the random polypropylene include Prime Polypro F744NP and F-300SP manufactured by Prime Polymer Co., Ltd. Examples of the block polypropylene include NOVATEC BC3HF and BC5FA manufactured by Japan Polypropylene Corporation.
Other than the above, the polyolefin resin may be a cyclic polyolefin such as polynorbornene. Furthermore, as the polyolefin resin, from the viewpoint of sealability and strength properties (such as tensile strength and impact strength), a linear polyolefin is preferable, and the linear polyolefin may be straight-chain or branched.
Examples of an α olefin component in the ethylene-α-olefin copolymer and propylene-α-olefin copolymer include ethylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, and 4-methyl-1-pentene. The copolymer may be a random copolymer or a block copolymer.
The modified polypropylene is obtained, for example, by graft modification of a polypropylene with an unsaturated carboxylic acid derivative component derived from unsaturated carboxylic acid, an acid anhydride of unsaturated carboxylic acid, an ester of unsaturated carboxylic acid, or the like. Furthermore, as the polypropylene resin, modified polypropylenes such as a hydroxyl group-modified polypropylene and acrylic-modified polypropylene can also be used. As an α olefin component that is used for obtaining a propylene-based copolymer, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 4-methyl-1-pentene, and the like can be exemplified.
Examples of the filler 21b include organic fillers such as an olefin filler and an acrylic filler, inorganic fillers such as a silica filler, and a porous filler.
Examples of the olefin filler include MIPELON (registered trademark) series manufactured by Mitsui Chemicals, Inc. and CS series manufactured by SUMITOMO CHEMICAL COMPANY, LIMITED.
Examples of acrylic filler include the MX series manufactured by Soken Chemical & Engineering Co., Ltd. and Uni-Powder NMB series manufactured by ENEOS LC COMPANY, LIMITED.
Examples of the silica filler include SMOOTH MASTER series manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd., SYLOPHOBIC series manufactured by FUJI SILYSIA CHEMICAL LTD., ADMAFINE SO series manufactured by ADMATECHS COMPANY LIMITED, Silica TMS series manufactured by TAYCA CORPORATION, and SUNSPHERE series manufactured by AGC Si-Tech Co., Ltd.
Examples of the porous filler composed of an organic substance include TECHPOLYMER MBP series manufactured by Sekisui Kasei Co., Ltd., and TECHPOLYMER ACP series manufactured by Sekisui Kasei Co., Ltd.
Examples of the porous filler composed of an inorganic substance include SYLOPHOBIC series manufactured by FUJI SILYSIA CHEMICAL LTD., and SUNSPHERE series manufactured by AGC Si-Tech Co., Ltd.
One kind of the filler may be used singly, or two or more kinds thereof having different compositions, particle diameters, and the like may be used in combination.
In a case where the porous filler is contained in an appropriate content percentage in the first resin layer 21, this porous filler can adsorb the oil content Co, and absorption of the oil content Co contained in the oil-in-water dispersion-type content C into the first resin layer 21 is promoted. In this case, the oil film Fo is easy to be more stably formed between the surface S of the first resin layer 21 and the content C by the synergistic effect between irregularities on the surface S of the first resin layer 21 and improvement in lipophilicity attributable to oil absorption. Therefore, further excellent slip-down property with respect to the content C is likely to be exhibited.
The porous filler can include a main body portion. The main body portion included in the porous filler may be an inorganic substance or an organic substance. Examples of the organic substance include a polyolefin resin and an acrylic resin. Examples of the acrylic resin include crosslinked poly(meth)acrylic acid esters such as crosslinked polymethyl methacrylate. These can be used singly or in combination with two or more kinds thereof. Examples of the inorganic substance include mineral fillers such as silica, talc, ceramics, glass beads, and calcium carbonate, carbon black, glass fibers, ceramic fibers, and carbon fibers. These can also be used singly or in combination with two or more kinds thereof.
The porous filler may further include a covering portion covering at least a part of the main body portion. The covering portion may be configured by a hydrophilic material or a hydrophobic material, and is preferably configured by a hydrophobic material. Herein, the hydrophobic material refers to a material having a DBA (di-n-butylamine) value of 200 mEq/kg or less, and the DBA value refers to an amount of DBA adsorbed to the surface of the main body portion. The DBA value corresponds to the amount of DBA adsorbed to the hydroxyl group on the surface of the main body portion, and the smaller the DBA value, the less the hydroxyl group (higher hydrophobicity).
The porous filler configured by the main body portion and the covering portion can be obtained, for example, by chemically reacting the main body portion with a raw material of the hydrophobic material, that is, by hydrophobizing the main body portion. Examples of the raw material of the hydrophobic material include an organosilicon compound. Among them, the raw material of the hydrophobic material is preferably an organosilicon compound.
The average particle diameter of the fillers 21b is determined according to the type of the fillers by the following method.
In a case where the laser diffraction type particle size distribution measurement is not suitable or is difficult, the average particle diameter of the fillers 21b may be determined using an optical microscope such as a scanning electron microscope (SEM) or a laser microscope.
Regarding any particles in the field of view observed by microscope observation, lengths of the maximum diameter and the minimum diameter of the particles are measured and a value obtained by dividing the sum of the lengths by 2 is regarded as the particle diameter. The particle diameters of a plurality of particles are measured and calculated, and an average value thereof is regarded as the average particle diameter. The number of any particles described above is preferably 10 or more.
The average particle diameter of the fillers 21b is preferably 3 μm or more. In this case, since appropriate irregularities (arithmetic mean height Sa) can be provided by adding an appropriate amount of the fillers 21b, the slip-down property of the content C can be efficiently improved while reducing the influence on physical properties of the packaging material film 20 such as seal strength reduction.
The average particle diameter of the fillers 21b is more preferably 5 μm or more and particularly preferably 7 μm or more.
The average particle diameter of the fillers 21b is preferably 30 μm or less. In this case, as compared with a case where the average particle diameter of the fillers 21b exceeds 30 μm, the oil film Fo is more easily formed on the surface of the first resin layer 21, and the packaging material film 20 can impart more excellent slip-down property to the oil-in-water dispersion-type content C enclosed in the package body.
The average particle diameter of the fillers 21b is more preferably 20 μm or less and further preferably 15 μm or less.
The content percentage of the fillers 21b in the first resin layer 21 is preferably 0.5 to 30% by mass. In this case, as compared with a case where the content percentage of the fillers 21b is out of the above range, the packaging material film 20 is easy to impart more excellent slip-down property to the oil-in-water dispersion-type content C enclosed in the package body. The content percentage of the fillers 21b in the first resin layer 21 is preferably 1 to 15% by mass and more preferably 3 to 10% by mass. The contained amount of the fillers 21b in the first resin layer 21 is, for example, 0.5 to 10 parts by mass, preferably 1 to 8 parts by mass, and more preferably 2 to 8 parts by mass, with respect to 100 parts by mass of the polyolefin resin. When the contained amount of the fillers 21b is within the above range, appropriate irregularities can be provided to the surface S of the first resin layer 21.
The thickness of the first resin layer 21 refers to a value determined as follows.
The thickness of the first resin layer 21 is, for example, 2 to 100 μm, preferably 4 to 70 μm, more preferably 6 to 50 μm, and further preferably 8 to 30 μm. When the thickness of the first resin layer 21 is within the above range, both of the slip-down property of the content C and the heat-sealability can be achieved in a high level. Herein, the heat-sealability refers to, for example, a property that enables heat sealing under conditions of 100° C. to 200° C. and 0.1 to 0.3 MPa for 1 to 3 seconds.
In the first embodiment, the water sliding angle at room temperature of the oil film Fo on the surface S of the first resin layer 21 as measured by the following measurement method described below is 200 or less. That is, this means that the surface S of the first resin layer 21 on the side of the content C has appropriate irregularities due to the fillers 21b, the oil content Co contained in the content C is absorbed by the first resin layer 21, and thus the lipophilicity of the first resin layer 21 is improved. The water sliding angle is preferably 15° or less and more preferably 10° or less. The lower limit of the water sliding angle is not particularly limited, and can be preferably set to 5°. The water sliding angle can be changed by appropriately adjusting the degree of formation of protrusions by the fillers 21b on the surface S of the first resin layer 21 from the viewpoint of the amount and particle diameter of the fillers 21b.
In the first embodiment, the amount of the oil film Fo formed on the surface S of the first resin layer 21 is preferably 0.2 to 1.2 g/200 cm2. When the amount of the oil film is within the above range, favorable slip-down property with respect to the content is easily maintained. In a case where the amount of the oil film Fo exceeds the upper limit value, since an amount of the oil film is formed that exceeds the amount needed to promote slip-down property, an excess oil film remains in the packaging bag, and the discharged amount of the content is likely to decrease. When the amount of the oil film Fo is less than the lower limit value, the oil film retaining and stabilizing action by the protrusions is likely to be insufficient, and the slip-down property with respect to the content C is likely to decrease. The amount of the oil film Fo is more preferably 0.4 g/200 cm2 or more and further preferably 0.6 g/200 cm2 or more. The amount of the oil film Fo is more preferably 1.0 g/200 cm2 or less and further preferably 0.8 g/200 cm2 or less. The amount of the oil film Fo is calculated from the weights of a sample before and after wiping off the oil film formed by the measurement method with isopropyl alcohol (IPA).
In the second embodiment, the arithmetic mean height Sa of the surface S of the first resin layer 21 may be appropriately adjusted in a range where the above ratio Y/X is 0.4 to 8.0 μm−1, and is preferably 2.0 μm or less. This facilitates the formation of appropriate irregularities on the surface S of the first resin layer 21, and more excellent slip-down property can be imparted to the oil-in-water dispersion-type content C. The arithmetic mean height Sa of the surface S is more preferably 1.5 μm or less and further preferably 1 μm or less.
The arithmetic mean height Sa of the surface S is preferably 0.1 μm or more, more preferably 0.3 μm or more, and further preferably 0.5 μm or more.
The surface area ratio of the surface S of the first resin layer 21 may be appropriately adjusted in a range where the above ratio Y/X is 0.4 to 8.0 μm−1, and is preferably more than 1.00. This facilitates the formation of appropriate irregularities on the surface S of the first resin layer 21, and more excellent slip-down property can be imparted to the oil-in-water dispersion-type content C. The surface area ratio of the surface S is more preferably 1.01 or more and further preferably 1.02 or more.
The surface area ratio of the surface S is preferably 1.10 or less, more preferably 1.09 or less, and further preferably 1.08 or less.
The arithmetic mean height Sa and the surface area ratio of the surface S can be adjusted, for example, by the blending amount and the average particle diameter of the fillers 21b, and the film formation conditions (such as a thickness and a temperature) of the first resin layer 21. Note that, values of the “arithmetic mean height Sa” and the “surface area ratio” described herein mean values measured using a laser microscope (trade name “OLS-4000”, manufactured by Olympus Corporation) under the following condition.
A ratio Y/X of a surface area ratio Y of the surface S of the first resin layer 21 with respect to an arithmetic mean height Sa X μm of the surface S of the first resin layer 21 is 0.4 to 8.0 μm−1. When the ratio Y/X is within the above range, appropriate irregularities are formed on the surface S of the first resin layer 21. In a case where the ratio Y/X is less than the lower limit value, Sa tends to be excessively large, which may prevent the content C from sliding down. In a case where the ratio Y/X exceeds the upper limit value, since Sa is small and contributes little to an increase in surface area ratio, it is difficult to obtain an effect of retaining and stabilizing an oil film to be formed. The ratio Y/X is preferably 0.7 μm−1 or more, more preferably 1.0 μm−1 or more, and further preferably 1.2 μm−1 or more. The ratio Y/X is preferably 7.0 μm−1 or less, more preferably 5.0 μm−1 or less, and further preferably 4.0 μm−1 or less.
In the second embodiment, a projected area ratio of protrusions formed by the fillers 21b on the surface S of the first resin layer 21 is preferably 8 to 45%. The projected area ratio is a two-dimensional parameter in which the number of the fillers 21b contributing to the formation of protrusions on the surface S of the first resin layer 21, the size thereof, the degree of projection on the surface S, and the like are reflected. For example, the projected area of one filler 21b depends on the particle diameter of the filler 21b and the degree of projection on the surface S, and even when the protrusions are formed by the fillers 21b having the same particle diameter, the projected area are changed by the degree of projection. The projected area ratio is calculated by the following formula when a flat portion of the surface S is designated as “area I” and the protrusion is designated as “area II”. Note that, the area I and the area II are determined by binarizing an image observed with a microscope with a threshold value based on luminance.
Projected area ratio=Area II/(Area I+Area II)×100[%]
When the projected area ratio exceeds the upper limit value, the protrusions are excessively large, and the slip-down property with respect to the content C is likely to decrease. When the projected area ratio is less than the lower limit value, the oil film retaining and stabilizing action by the protrusions is likely to be insufficient, and the slip-down property with respect to the content C is likely to decrease. The projected area ratio is preferably 10% or more, more preferably 12% or more, and further preferably 15% or more. The projected area ratio is preferably 42% or less, more preferably 40% or less, and further preferably 38% or less.
The first resin layer 21 may further contain an elastomer component from the viewpoint of exhibiting further excellent slip-down property. Examples of the elastomer component include a block copolymer of polypropylene and polyethylene, a block copolymer of polyethylene and ethylene-butylene, a block copolymer of polyethylene and ethylene-octene, an ethylene-based elastomer, a propylene-based elastomer, a butene-based elastomer, and a reactor TPO. The reactor TPO (reactor thermoplastic polyolefin) is one kind of olefin-based thermoplastic elastomers (TPO) and is, for example, configured by a polypropylene as a base resin and a rubber component finely dispersed therein by adding a high-concentration rubber component during polymerization. Examples of the ethylene-based elastomer and the propylene-based elastomer include TAFMER series manufactured by Mitsui Chemicals, Inc. One kind of the elastomer component may be used singly, or two or more kinds thereof may be used in combination.
The added amount of the elastomer component (the total amount in a case where a plurality of elastomer components are added) is, for example, 30 parts by mass or less, preferably 1 to 25 parts by mass, more preferably 2 to 20 parts by mass, and further preferably 3 to 15 parts by mass, with respect to 100 parts by mass of the polyolefin resin. The amorphous part (rubber component) contained in the elastomer component has a property of absorbing oil. Therefore, the elastomer component promotes stable and uniform formation of the oil film Fo, and thereby the slip-down property with respect to the content C is even more improved.
The second resin layer 22 is a layer provided between the first resin layer 21 and the substrate 10. When the packaging material 100 further includes the second resin layer 22, the functions (such as heat-sealability, heat resistance, impact resistance, and oxygen/water vapor barrier properties) of the second resin layer 22 can impart to the packaging material 100. For example, from the viewpoint of improving heat-sealability, the second resin layer 22 preferably contains a thermoplastic resin. Specific examples of the thermoplastic resin include a polyolefin resin, an ethylene-α,β unsaturated carboxylic acid copolymer or an esterified product or ion-crosslinked product thereof, an ethylene-vinyl acetate copolymer or a saponified product thereof, polyvinyl acetate or a saponified product thereof, a polycarbonate resin, a thermoplastic polyester resin, an ABS resin, a polyacetal resin, a polyamide resin, a polyphenylene oxide resin, a polyimide resin, a polyurethane resin, a polylactic resin, a furan resin, and a silicone resin. These thermoplastic resins can be used singly or in combination of two or more types thereof.
The thickness of the second resin layer 22 can be appropriately set according to applications of the packaging material 100. The thickness of the second resin layer 22 is, for example, 1 to 300 μm, preferably 2 to 200 μm, more preferably 5 to 150 μm, and further preferably 10 to 100 μm.
The substrate 10 serves as a support and is not particularly limited as long as it has durability with respect to the heating treatment such as a retort treatment or a boiling treatment, and examples thereof include a resin film and a metal foil. Examples of the resin film include films containing at least one kind of polyolefins (such as polyethylene (PE) and polypropylene (PP)), acid-modified polyolefins, polyesters (such as polyethylene terephthalate (PET)), polyamide (PA), polyvinyl chloride (PVC), acetylcellulose, and a cellophane resin. This film may be a stretched film or may be an unstretched film. Examples of the metal foil include an aluminum foil and a nickel foil. The substrate 10 may be obtained by laminating a plurality of substrates each made of a different material, or may include a coating layer or a metal deposition layer.
The thickness of the substrate 10 can be appropriately set according to applications of the packaging material 100. The thickness of the substrate 10 is, for example, 1 to 500 μm and may be 10 to 100 μm.
The adhesive layer 30 attaches the packaging material film 20 (a laminate of the first resin layer 21 and the second resin layer 22) and the substrate 10 to each other. The adhesive constituting the adhesive layer 30 is not particularly limited as long as it can attach the packaging material film 20 and the substrate 10 to each other, and examples of such an adhesive include polyurethane resins obtained by causing a bifunctional or higher isocyanate compound to act on main agents such as polyester polyol, polyether polyol, acrylic polyol, and carbonate polyol, and the like. Various polyols may be used singly or in combination of two or more kinds thereof.
In the adhesive layer 30, a carbodiimide compound, an oxazoline compound, an epoxy compound, a phosphorus compound, a silane coupling agent, or the like may be blended with the polyurethane resin described above, for the purpose of adhesion promotion. Other various additives or stabilizing agents may be blended with the polyurethane resin described above according to the performance required in the adhesive layer 30.
The thickness of the adhesive layer 30 is, for example, 1 to 10 μm and may be 3 to 7 μm, from the viewpoint of obtaining desired adhesion strength, followability, processability, and the like.
An adhesive primer (anchor coat) can also be provided on the substrate 10, and as a material therefor, a polyester-based resin, a polyurethane-based resin, a polyallylamine-based resin, a polyethylenimine-based resin, a polybutadiene-based resin, an ethylene-vinyl acetate copolymer, and the like can be used. Various curing agents or additives that can be used as an adhesive may be blended, as necessary, in the adhesive primer.
Next, a method for manufacturing the aforementioned packaging material will be described.
The packaging material 100 can be obtained by pasting the packaging material film 20 and the substrate 10 together. Examples of a method of pasting the substrate 10 and the packaging material film 20 together include a lamination method with an adhesive and a lamination method by a thermal treatment.
As the lamination method with an adhesive, various known lamination methods such as a dry lamination method, a wet lamination method, and a non-solvent lamination method can be used.
Examples of the lamination method by a thermal treatment roughly include the following methods (1) to (4):
Next, an embodiment of the package body of the present invention will be described with reference to
As illustrated in
According to the package body 300, the packaging material film 20 included in the packaging material 100 forming the packaging bag 200 is subjected to a heating treatment, so that excellent slip-down property can be imparted to the oil-in-water dispersion-type content C that comes into contact with the first resin layer 21. Therefore, when the package body 300 is subjected to the heating treatment such as a retort treatment or a boiling treatment, the oil-in-water dispersion-type content C can be easily slipped down at the time of discharging the oil-in-water dispersion-type content C from the package body 300 after the package body 300 is opened. Thus, the residual liquid amount of the oil-in-water dispersion-type content C can be reduced, waste of the content C can be prevented, contamination due to adhesion of the content C can be prevented, and a discharge operation of the content C can be efficiently performed.
The package body 300 can be obtained by forming the packaging bag 200 using the packaging material 100 and enclosing the oil-in-water dispersion-type content C in the packaging bag 200.
Hereinbefore, the embodiments of the present invention have been specifically described; however, the present invention is not limited to the above-described embodiments. For example, in the above-described embodiment, the packaging material film 20 is configured by the first resin layer 21 and the second resin layer 22, but the packaging material film 20 may be configured only by the first resin layer 21.
Furthermore, the packaging material 100 includes the adhesive layer 30 attaching the packaging material film 20 and the substrate 10 to each other, but the adhesive layer 30 can be omitted as long as the packaging material film 20 and the substrate 10 can be directly fused.
Hereinafter, the present invention will be described in more detail on the basis of Examples and Comparative Examples; however, the present invention is not limited to the following Examples.
Materials used in each Experimental Example are as follows.
A packaging material film (sealant film) of a two-layer configuration including the first resin layer having a composition each shown in Tables 1 to 4 and the second resin layer composed of the block polypropylene resin (A3) was produced using a co-extruder. At this time, the mixing ratio of the random polypropylene resin (A1) and the block polypropylene resin (A2) in the first resin layer was set to 50/50 at a mass ratio. Table 1 and Table 2 relate to the first invention, and Table 3 and Table 4 relate to the second invention.
In Table 2, in Experimental Example 29, the surface properties of the first resin layer were adjusted by mirror finishing (smoothing treatment), and in Experimental Example 30, the surface properties of the first resin layer were adjusted by a shaping treatment. In Table 4, in Experimental Example 29, the surface properties of the first resin layer were adjusted by mirror finishing (smoothing treatment), and in Experimental Examples 30 and 31, the surface properties of the first resin layer were adjusted by a shaping treatment.
Next, the obtained packaging material film and a PET film (trade name “EMBLET”, manufactured by UNITIKA LTD.) having a thickness of 38 μm as a substrate were dry-laminated using a polyurethane-based adhesive (manufactured by Mitsui Chemicals, Inc.) and were aged at 50° C. for 5 days to obtain a packaging material. Note that, in respective examples, the first resin layer and the second resin layer were formed so that the total thickness of the first resin layer and the second resin layer was 60 μm.
The arithmetic mean height Sa and the surface area ratio of the first resin layer was measured for the packaging material in each example by using a laser microscope (trade name “OLS-4000”, manufactured by Olympus Corporation) under the following condition. Results are shown in Table 3 and Table 4.
The projected area ratio of the first resin layer of the packaging material of each example was measured using a digital microscope (trade name “VHX-1000”, manufactured by KEYENCE CORPORATION) according to the following procedures. Results are shown in Table 3 and Table 4.
(Residual Liquid Evaluation after Retort Treatment)
The slip-down property of the content after the retort treatment of the packaging material obtained in each example was evaluated by the method illustrated in
First, two packaging materials obtained by cutting the packaging material into a size of 150 mm in length×138 mm in width were prepared. Then, the two packaging materials were superimposed such that the respective first resin layers face inward, and three sides were sealed using a heat sealer. In this way, as illustrated in
Next, as illustrated in
Thereafter, the opening portion (the remaining side) was sealed using a heat sealer to form a sealed portion 200b on the remaining side as illustrated in
The package body 300 thus produced was put in a high-temperature, high-pressure cooking and sterilizing device (manufactured by Hitachi Capital Corporation) and subjected to a retort treatment with a high-temperature water vapor. The retort treatment was performed under the following conditions.
After the retort treatment, the package body 300 was subjected to a heat treatment in a hot water (boiling treatment) at 100° C. over 5 minutes. Thereafter, as illustrated in
The same measurement was performed three times while changing the package body 300, and the average value of the residual liquid ratios for three measurements was calculated as an average residual liquid ratio. Furthermore, based on the average residual liquid ratio, the slip-down property of the content was evaluated according to the following evaluation criteria. The average residual liquid ratio and the evaluation results of the slip-down property of the content are shown in Tables 1 to 4.
A: The average residual liquid ratio is less than 6.5%.
B: The average residual liquid ratio is 6.5% or more and less than 8.0%.
C: The average residual liquid ratio is 8.0% or more and less than 10.0%.
D: The average residual liquid ratio is 10.0% or more.
(Appearance Evaluation after Retort Treatment)
When the residual liquid ratio was measured as described above, the discharge behavior of the content C when the content (curry) C was discharged from the inside of the pouch was visually observed, and the appearance was also evaluated according to the following evaluation criteria. Results are shown in Tables 1 to 4.
A: It is observed that the content slips down cleanly, and there is almost no adhesion of the content to the packaging material film.
B: It is observed that the content slips down, and the amount of the content adhering to the packaging material film is small.
C: It is observed that the content slips down, but the amount of the content adhering to the packaging material film is large.
D: It is not observed that the content slips down.
The pouch used in the slip-down property evaluation of the content was washed with water, and the moisture content was dried. A drop of water at room temperature was dropped on the first resin layer (on the oil film) on the inner surface of the pouch, and an angle at which the drop of water began to move was measured using a sliding angle meter. The same measurement was performed three times while changing the package body 300, and the average value thereof was regarded as a sliding angle (°). Results are shown in Table 1 and Table 2.
Measuring apparatus: simple contact angle meter DSA25 manufactured by KRUSS GmbH
The pouch used in the slip-down property evaluation of the content was washed with water, and the moisture content was dried. Two packaging materials constituting the pouch were cut into a size of 10 cm in length×10 cm in width, and the weight of each piece with the oil film attached was measured to determine a total weight “a”. Then, the surface of the first resin layer was wiped off with isopropyl alcohol (IPA) and dried sufficiently, and then the weight of each piece with the oil film removed was measured to determine a total weight “b”. Then, a difference (a−b) between “a” and “b” was calculated. This operation was performed three times while changing the package body 300, and the average value thereof was regarded as an oil film amount (g/200 cm2). Results are shown in Table 1 and Table 2.
From the results shown in Table 1 and Table 2, in the package bodies obtained in Experimental Examples 1 to 28 (Examples), the average residual liquid ratio was small, and in appearance, it was observed that the content slipped down. On the other hand, in the package bodies obtained in Experimental Examples 29 to 31 (Comparative Examples), the average residual liquid ratio was large, and in appearance, it was not observed that the content slipped down.
From the results shown in Table 3 and Table 4, in the package bodies obtained in Experimental Examples 1 to 28 (Examples), the average residual liquid ratio was small, and in appearance, it was observed that the content slipped down. On the other hand, in the package bodies obtained in Experimental Examples 29 to 33 (Comparative Examples), the average residual liquid ratio was large, and in appearance, it was not observed that the content slipped down.
As described above, according to the packaging material film of the present invention, it was confirmed that excellent slip-down property can be imparted to the oil-in-water dispersion-type content by the heating treatment.
10: substrate, 20: packaging material film, 21: first resin layer, 21a: resin composition, 21b: filler, 30: adhesive layer, 100: packaging material, 200: packaging bag, 300: package body, C: content, Co: oil content, S: surface of first resin layer, Fo: oil film.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2021-083264 | May 2021 | JP | national |
| 2021-083267 | May 2021 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2022/018431 | 4/21/2022 | WO |
