JP6923519B2 - Packaging sheet and packaging - Google Patents

Description

The present invention relates to novel packaging sheets and packaging bodies. In particular, the present invention relates to a packaging sheet used for a packaging body for packaging foods having a surface easily adhered to, and which is soft and easily peeled off or damaged, and a packaging body using the same.

In general, foods with a high water content such as souffle, castella, and cake have the property that the surface easily adheres to the material that wraps them. When the surface of the food adheres to the packaging sheet, it becomes difficult to take out the food from the packaging body, and there is also a problem that a part of the food adheres to the packaging sheet, causing peeling, damage, and the like. Therefore, when packaging such foods, the packaging sheet is particularly required to have non-adhesiveness to the contents.

For example, Patent Document 1 discloses a food containing food in a state of containing air and using an embossed film inside the package. The uneven shape of the surface of the embossed film reduces the contact area with the contents and reduces the adhesion of the contents to the inner surface of the package.

JP-A-2007-308191

However, in a package such as Patent Document 1, the softer the content, the more the surface of the content is deformed along the uneven shape of the surface of the embossed film, and the surface of the content adheres to the portion in contact with the surface of the embossed film. Resulting in. That is, in the above-mentioned package, it is not possible to sufficiently prevent the surface of the contents from adhering to the inner surface of the package.

Further, in the embossed film, when heat-sealing between heat-sealing layers (hereinafter, also referred to as "face-to-face heat-sealing"), there is a possibility that sufficient heat-sealing strength cannot be obtained due to the uneven shape.

Therefore, a main object of the present invention is to provide a packaging sheet which is excellent in heat-sealing property on the surface and the surface of the contents is less likely to adhere.

As a result of intensive research in view of the problems of the prior art, the present inventor has found that the above object can be achieved by adopting a heat seal layer having a specific structure and physical properties for a packaging sheet and a packaging body. The invention was completed.

That is, the present invention relates to a packaging sheet and a packaging body.
1. 1. A packaging sheet containing a base film and a heat-sealing layer laminated on at least one surface of the base film.
(1) The heat-sealing layer contains a heat-sealing agent and polyolefin-based particles, and has a surface roughness Ra of 1.00 to 7.00 μm on the surface opposite to the base film.
(2) The polyolefin-based particles have an average particle size D50 of 10 to 50 μm and a melting point of 100 to 180 ° C.
A packaging sheet characterized by that.
2. Item 2. The packaging sheet according to Item 1, wherein the polyolefin-based particles have a specific gravity of 0.93 to 1.06.
3. 3. Item 2. The packaging sheet according to Item 1, wherein the polyolefin-based particles are at least one of polyethylene-based particles and polypropylene-based particles.
4. Item 2. The packaging sheet according to Item 1, wherein the base film is one or more of polypropylene-based film, polyethylene-based film, and polyester-based film.
5. ^{Item 2.} The packaging sheet according to Item 1, wherein the amount of the heat seal layer formed is 0.5 to 10.0 g / m 2.
6. Item 2. The packaging sheet according to Item 1, wherein the heat sealant contains a polyolefin resin.
7. Item 2. The packaging sheet according to Item 1, wherein an adhesion prevention layer containing particles having water repellency and / or oil repellency is further provided on the surface of the heat seal layer.
8. A package formed by the packaging sheet according to any one of Items 1 to 7 above.
(1) The packaging sheet is arranged so that the heat seal layer is inside the packaging body.
(2) The heat seal layers are joined to each other at least in part.
A packaging body characterized by that.
9. A product in which the contents are contained in the package according to Item 8 and at least a part of the heat seal layers are bonded to each other so that the contents are sealed in the package.

According to the present invention, it is possible to provide a packaging sheet which is excellent in heat-sealing property and whose contents are less likely to adhere. In particular, since the packaging sheet of the present invention is provided with a heat-sealing layer having a predetermined structure and physical properties on one side, even if the contents come into contact with the packaging body molded with the heat-sealing layer arranged inside, the contents come into contact with each other. Even if it does not adhere easily. In particular, even foods that are generally soft and easily adhere to packaging bags and the like due to their high water content effectively exhibit the property of being difficult to adhere due to the material and characteristics of the heat seal layer of the present invention. be able to.

On the other hand, the heat-sealing layer in the packaging sheet of the present invention is excellent in heat-sealing property even though it has high non-adhesiveness to food as described above, so that the contents can be sealed more reliably. Can be done. In particular, in the present invention, since particles composed of specific resin components called polyolefin-based particles are dispersed in the heat-sealing layer, good heat-sealing properties can be realized.

Further, when the packaging sheet of the present invention is molded with the surface on which the heat seal layer is formed as the inside, the inside of the packaging has a specific uneven shape, while the outside of the packaging can maintain a smooth surface. It is possible to smoothly print and display raw materials, barcodes, product names, expiration dates, etc. of goods. In this respect, when a conventional embossed film is used, it is difficult to print on the embossed film. Therefore, it is necessary to prepare a packaging sheet separately from the embossed film. However, in the packaging sheet of the present invention, the packaging body is used. When molding, it is not necessary to prepare and use such a separate packaging sheet.

Such packaging sheets or packaging bodies can be suitably used for packaging various products such as foods, pharmaceuticals, and cosmetics. In particular, for packaging foods whose surface easily adheres to the packaging sheet due to its high water content and which is soft and easily peeled off or damaged (for example, Western-style confectionery, Western-style confectionery, Japanese-style confectionery, Japanese-style namagashi, etc.). It can be effectively used as a packaging sheet or a packaging body for accommodating the food.

It is a figure which shows the layer structure of the packaging sheet of this invention. It is a figure which shows an example of the packaging body using the packaging sheet of this invention.

1. 1. Packaging sheet The packaging sheet of the present invention is a packaging sheet containing a base film and a heat-sealing layer laminated on at least one surface of the base film.
(1) The heat-sealing layer contains a heat-sealing agent and polyolefin-based particles, and has a surface roughness Ra of 1.00 to 7.00 μm on the surface opposite to the base film.
(2) The polyolefin-based particles have an average particle size D50 of 10 to 50 μm and a melting point of 100 to 180 ° C.
It is characterized by that.

An example of the layer structure of the packaging sheet of the present invention is shown in FIG. As shown in FIG. 1, in the packaging sheet 10 of the present invention, the heat seal layer 12 is laminated on one surface of the base film 11. In the heat seal layer 12, polyolefin particles 14 (particularly polyethylene particles and / or powder containing polypropylene particles) are dispersed in the heat seal agent 13. Then, in the heat seal layer 14, predetermined irregularities are formed on the surface opposite to the base film 11 due to the inclusion of polyolefin-based particles and the like. The heat seal layer 12 may be laminated directly adjacent to the base film 11 as shown in FIG. 1, or may be laminated via another layer (for example, a primer layer or the like).

In the packaging sheet having such a structure, the material of the heat seal layer and the uneven shape can be combined to exhibit a predetermined non-adhesiveness. That is, even if the contents come into contact with the heat seal layer (or the adhesion prevention layer formed on the surface thereof), the heat seal layer and the contents do not adhere to each other, and a good non-adhesion state can be maintained. can. In particular, in the case of foods such as namagashi or semi-namagashi, which contain a relatively large amount of water and therefore have a soft surface and easily adhere to the surface, the surface of the food easily adheres to or adheres to a general packaging sheet according to the prior art. Although the properties are improved, the packaging sheet of the present invention can effectively suppress or prevent the adhesion of such namagashi or semi-namagashi.

Further, since the melting point of the polyolefin-based particles contained in the heat-seal layer is controlled to 100 to 180 ° C. (particularly 110 to 180 ° C.), high heat-sealability can be exhibited. In particular, excellent performance can be exhibited also in the heat-sealing property (hereinafter, also referred to as "face-to-face heat-sealing property") between the heat-sealing layers of the packaging sheet of the present invention. In particular, when the heat sealant contains polypropylene as a resin component, higher heat sealability can be obtained.

Hereinafter, the materials, manufacturing methods, usage methods, etc. that constitute the packaging sheet of the present invention will be described.

(1) Structure of Packaging Sheet (1-1) Base Film In the present invention, a known resin film can be used as the base film. The material of the resin film is not limited, but one or more selected from polypropylene-based resin, polyethylene-based resin, and polyester-based resin can be appropriately used. Therefore, in the present invention, for example, at least one of polypropylene-based film, polyethylene-based film, and polyester-based film can be suitably used as the base film.

The polypropylene-based film may be a film having a polypropylene content of 50% by weight or more, preferably 80% by weight or more, and more preferably 90% by weight or more. Therefore, the polypropylene may be, for example, either a homopolymer containing propylene as a monomer or a copolymer. Further, a mixed resin, a polymer alloy or the like in which other resin components are mixed may be used as long as the effects of the present invention are not impaired. In the present invention, for example, biaxially stretched polypropylene having high polypropylene purity (for example, a homopolymer of propylene) can be preferably used. In the present invention, the "main component" means that the content thereof is 50% by weight or more (the same applies hereinafter). Therefore, for example, it may be 80% by weight or more. Further, for example, it may be 90% by weight or more (the same applies hereinafter to these points).

The polyethylene-based film may be a film containing polyethylene as a main component. Polyethylene is a polymer film having a structure in which ethylene is polymerized. For example, high-density polyethylene having a density of 0.92 or more and 0.96 or less, low-density polyethylene having a density of 0.91 or more and 0.92 or less, and a density of polyethylene are Various polyethylenes such as linear low density polyethylene of 0.94 or less can be used.

The polyester-based film may be a film containing polyester as a main component. As the polyester, a polycondensate of a polyvalent carboxylic acid and a polyalcohol or the like can be preferably used. Therefore, as the polyester-based film, for example, polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate and the like can be used.

Further, the base film may be either a stretched film or an unstretched film. Further, as the stretched film, either a uniaxially stretched film or a biaxially stretched film can be used. Therefore, in the present invention, for example, a biaxially stretched polypropylene-based film (OPP) can be preferably used as the base film. As a result, excellent performance in tensile strength, transparency, moisture resistance, heat resistance, tearability, etc. can be obtained, and it is also advantageous in that cost can be reduced. Further, as the biaxially stretched polypropylene-based film, various types of films subjected to surface treatment such as corona treatment can also be used as the base film.

Further, the base film may be either a single-layer type or a multi-layer type. As the multilayer type resin film, for example, a heat seal type resin base film in which a heat seal layer is laminated on at least one surface of a film (particularly a polyolefin film) can also be used. Thereby, higher sealing property can be obtained. As such a heat-seal type base film itself, a known or commercially available one can be used.

As such a heat-sealing type base film, for example, a double-sided or single-sided heat-sealing type biaxially stretched polypropylene film (OPP) (laminated film) can also be suitably used as the base film. That is, a laminated film in which a heat seal layer is laminated on at least one surface of a biaxially stretched polypropylene-based film can be preferably used as a base film. As the heat-sealing layer, for example, a polyethylene-based heat-sealing layer, a polypropylene-based heat-sealing layer, or the like can be adopted.

The thickness of the base film is not particularly limited, but is usually preferably 20 to 80 μm, and more preferably 25 to 50 μm. If the thickness of the base film is less than 20 μm, it may expand and contract significantly in the width direction or the flow direction due to the drying heat of the packaging sheet, which may affect the processability. If the thickness of the base film exceeds 80 μm, the tearability and the like may decrease.

In addition, for example, a printing layer, an overcoat layer, various films, etc. are applied to the surface of the base film opposite to the surface in contact with the contents, that is, the surface exposed to the outside when molded as a package. It may be provided as appropriate.

(1-2) Heat Sealing Layer The heat sealing layer contains a heat sealing agent and polyolefin-based particles, and has a characteristic that the surface roughness Ra on the surface thereof is 1.00 to 7.00 μm. The heat seal layer is laminated on the base film, and is preferably arranged so as to be directly adjacent to the surface of the base film.

In the packaging sheet of the present invention, the heat seal layer is arranged as the outermost layer (outermost surface) or the lower layer of the adhesion prevention layer. For example, as shown in FIG. 1, a layer structure in which the heat seal layer 10 is arranged so as to be the outermost layer can be preferably adopted. That is, a layer structure having no adhesion prevention layer can also be preferably adopted. When the heat seal layer is arranged as the lower layer of the adhesion prevention layer, it is preferable that the heat seal layer is arranged as the lower layer adjacent to the adhesion prevention layer. As a result, high heat sealability can be ensured more reliably.

The surface roughness Ra of the heat seal layer is usually 1.00 to 7.00 μm, preferably 1.50 to 3.50 μm. If the surface roughness Ra is less than 1.00 μm, the desired adhesion prevention effect cannot be obtained. On the other hand, if the surface roughness Ra exceeds 7.00 μm, the desired heat sealability cannot be obtained. The surface roughness as described above can be appropriately adjusted by dispersing the polyolefin-based particles in the heat-sealing layer.

Formation of the heat seal layer is not particularly limited, particularly preferably to 0.5~10.0g / ^{m 2,} more and more preferably set to 1.0~4.0g / ^{m 2.} If the amount formed is ^{less than 0.5 g / m 2} , the sealing property is deteriorated and the airtightness as a package cannot be ensured. For example, oxidation of the contents, leakage of the contents, deterioration of shape retention of the contents is deteriorated. Etc. may be caused. On the other hand, if the amount formed exceeds 10.0 g / m ² , the effect of unevenness is reduced, and the contents may adhere to the inner surface of the package. The amount of the heat-sealing layer formed is not the total amount of the material of the heat-sealing layer composed of the heat-sealing agent, polyethylene-based particles, etc., but the weight of the base film based on the weight of the packaging sheet after drying after the coating work. It is the weight after deducting (weight per unit area).

The thickness of the heat seal layer is not particularly limited as long as it is within the above-mentioned forming amount. For example, it can be appropriately set within a range of about 0.1 to 100 μm according to the use of the packaging sheet and the like.

Heat Sealing Agent As the heat sealing agent, an adhesive containing a known heat sealing component can be used. For example, in addition to the constituent components of known sealant films, components used in adhesives such as lacquer type adhesives, easy peel adhesives, and hot melt adhesives can be adopted. Further, as the heat sealant, a liquid type commercially available product or the like can also be used.

The main components (resin components) constituting the heat seal layer are not limited, and are, for example, low-density polyethylene, medium-density polyethylene, high-density polyethylene, linear (linear) low-density polyethylene, polypropylene, polyester, and polystyrene. Epoxy resin, nitrocellulose resin, urethane resin, melamine resin, ethylene-vinyl acetate copolymer, vinyl chloride-vinyl acetate copolymer, ionoma-resin, ethylene-acrylic acid copolymer, acrylic-vinyl chloride-vinyl acetate Polymers, ethylene-ethyl acrylate copolymers, ethylene-methacrylic acid copolymers, ethylene-methyl methacrylate copolymers, ethylene-propylene copolymers, methylpentene polymers, polybutene polymers, polyethylene or polypropylene, etc. Acid-modified polyolefin resin, polyvinyl acetate resin, poly (meth) acrylic resin obtained by modifying a polyolefin resin with an unsaturated carboxylic acid such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, and itaconic acid. In addition to resins, polyacrylonitrile resins, polyvinyl chloride-based resins, and other heat-adhesive resins, blended resins thereof, copolymers containing a combination of monomers constituting them, modified resins, and the like can be used. Therefore, for example, a mixture of an acrylic resin and a vinyl chloride-vinyl acetate copolymer can be preferably used as the resin component.

The polyolefin-based particles are mainly composed of polyolefin, which is a polymer of monomers (olefins) such as ethylene and propylene, and homopolymers or copolymers containing ethylene and / or propylene as monomers are particularly preferable. Can be adopted. As the polyethylene, various types of polyethylene such as low-density polyethylene, medium-density polyethylene, high-density polyethylene, and linear (linear) low-density polyethylene can be used.

These polyolefin-based particles can be appropriately selected depending on the base film to be used, the filling machine, and the like. For example, when low temperature sealing property of about 80 ° C. to 120 ° C. is required, polyolefin-based particles containing polyethylene as a main component are preferable. Further, for example, when practically required heat resistance of 140 ° C. to 180 ° C., polyolefin-based particles containing polypropylene as a main component are preferable.

The average grain diameter D50 of the polyolefin-based particles is preferably 10 to 50 μm, and particularly preferably 15 to 30 μm. When the average particle size D50 of the polyolefin particles is less than 10 μm, the effect of preventing adhesion due to the uneven shape of the surface of the heat seal layer is reduced. Further, when the average particle size D50 of the polyolefin particles exceeds 50 μm, the heat sealability deteriorates and the airtightness as a package cannot be ensured. For example, oxidation of the contents, leakage of the contents, and shape retention of the contents It may cause deterioration of sex. Further, from the viewpoint of processing, for example, uneven coating is likely to occur, which may affect the appearance or performance.

The melting point of the polyolefin-based particles is usually 100 to 180 ° C., particularly preferably 110 to 160 ° C., and more preferably 130 to 140 ° C. If the melting point of the polyolefin-based particles is less than 100 ° C., the polyolefin particles are melted by the heat of drying during processing, and the desired effect due to the desired uneven shape cannot be obtained. Further, if the melting point exceeds 180 ° C., the predetermined heat-sealing property cannot be obtained.

The specific gravity of the polyolefin-based particles is not particularly limited, but is generally preferably 0.93 to 1.06. If the specific gravity is less than 0.93, it may become brittle and it may be difficult to maintain the shape. Further, if the specific gravity exceeds 1.06, it tends to settle in the heat seal layer, which may affect the processability.

The content (dispersion amount) of the polyolefin-based particles in the heat-sealing layer may be an amount such that the surface roughness Ra is 1.00 to 7.00 μm. For example, in the range of about 1 to 90% by weight in the heat seal layer, it can be appropriately adjusted according to the particle size, specific gravity and the like of the polyolefin-based particles used. Therefore, the content can be, for example, 10 to 60% by weight, and 15 to 50% by weight. Further, for example, it can be set to 20 to 40% by weight.

(1-3) Adhesion Prevention Layer The packaging sheet of the present invention exhibits sufficient non-adhesion even with the heat seal layer alone, but further, if necessary, adhesion prevention containing particles having water repellency and / or oil repellency. The layer may be partially or wholly formed on the heat seal layer. As a result, even if the content has a large amount of water, it is possible to more effectively suppress or prevent the content from sticking to the packaging sheet.

As the particles, known or commercially available particles can be used. For example, inorganic oxide particles or metal oxide particles can be used. Among these oxide particles, at least one kind of particles (powder) such as silicon oxide, titanium oxide, aluminum oxide, and zinc oxide can be preferably used. In particular, in the present invention, it is more preferable to use silicon oxide particles.

These particles are preferably fine particles, particularly preferably have an average primary particle size of 5 to 50 nm, and most preferably 7 to 30 nm.

In the present invention, the measurement of the average primary particle size and the like can also be carried out using a transmission electron microscope or a scanning electron microscope. More specifically, it can be obtained by photographing particles with a transmission electron microscope or a scanning electron microscope, measuring the diameters of 200 or more particles on the photographs, and calculating the arithmetic mean value thereof.

Known or commercially available particles can be used as such nano-level particles. For example, as silica, the product names are "AEROSIL R972", "AEROSIL R972V", "AEROSIL R972CF", "AEROSIL R974", "AEROSIL RX200", "AEROSIL RY50", "AEROSIL NY50", "AEROSIL RY200S", AEROSIL RY200S. "AEROSIL RY200" (manufactured by Nippon Aerosil Co., Ltd.), "AEROSIL R202", "AEROSIL R805", "AEROSIL R711", "AEROSIL R7200", "AEROSIL R812", "AEROSIL R812S", (above, Ebonic Degusa) , "Silohobic 100", "Silohobic 200", "Silohobic 603" (all manufactured by Fuji Silicia Chemical Co., Ltd.) and the like. Examples of titania include the product name "AEROXIDE TiO ₂ T805" (manufactured by Evonik Degussa). Examples of alumina include fine particles obtained by treating the product name "AEROXIDE Alu C" (manufactured by Evonik Degussa) with a silane coupling agent to make the particle surface hydrophobic.

Among these, hydrophobic silica fine particles can be preferably used. In particular, hydrophobic silica fine particles having a trimethylsilyl group on the surface are preferable in that more excellent non-adhesiveness can be obtained. Examples of commercially available products corresponding to this include the above-mentioned "AEROSIL R812" and "AEROSIL R812S" (both manufactured by Evonik Degussa).

The amount of hydrophobic particles adhered to the heat seal layer (weight after drying) is not limited, but is usually ^{preferably 0.01 to 10 g / m 2,} and 0.2 to 1.5 g / m ^2. More preferably, 0.2 to 1 g / m ² is most preferable.

Further, for example, metal oxide composite particles having oil repellency can also be used. By having a coating film containing such metal oxide composite particles, it is possible to suitably reduce adhesion even if the content has a large amount of fat. As the particle size of the oil-repellent metal oxide composite particles, those in the same range as the above-mentioned water-repellent metal oxide composite particles can be preferably used.

As the particles used as the oil-repellent metal oxide composite particles, for example, those in which a coating layer such as a polyfluoroalkyl methacrylate resin is formed on the surface of the core oxide fine particles can be used. Examples of such core oxide fine particles include silicon oxide, for example, product names "AEROSIL 200"("AEROSIL" is a registered trademark; the same applies hereinafter), "AEROSIL 130", "AEROSIL 300", "AEROSIL 50". , "AEROSIL 200FAD", "AEROSIL 380" (all manufactured by Nippon Aerosil Co., Ltd.) and the like. Examples of titanium oxide include the product name "AEROXIDE TiO ₂ T805" (manufactured by Evonik Degussa). Examples of aluminum oxide include the product name "AEROXIDE Alu C 805" (manufactured by Evonik Degussa). By using particles having such a coating layer, a strong coating layer having relatively high adhesion can be formed on the surface of the particles because of its excellent affinity with the metal oxide particles, and the content is high. Non-adhesiveness can be expressed.

The content of the water-repellent and / or oil-repellent particles in the adhesion-preventing layer is not limited, but is usually preferably 10 to 100% by weight. When the content of the particles is brought close to 100% by weight, higher water repellency and / or oil repellency can be obtained.

(2) Method for producing a packaging sheet The method for producing a packaging sheet of the present invention is not limited, and includes, for example, 1) a step of applying a liquid composition containing a heat sealant and polyolefin particles to the surface of a base film. A manufacturing method, 2) a manufacturing method including a step of laminating a sheet containing a heat sealant and a polyolefin-based particle on the surface of a base film can be adopted.

In the method 1) above, a liquid composition containing a heat sealant and polyolefin particles is used. As the liquid composition, for example, a dispersion obtained by dispersing polyethylene-based particles in a liquid heat sealant can also be preferably used.

Further, in the above liquid composition, a solvent can be used in particular to disperse the polyolefin-based particles and uniformly coat the surface of the base film. The solvent is not particularly limited as long as the polyolefin-based particles used are not dissolved. For example, at least one of water, alcohol-based (ethanol, isopropyl alcohol), toluene, xylene, ethyl acetate, butyl acetate, methylcyclohexane (MCH), and ketone-based (methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), etc.). It can be used as appropriate. These solvents can be removed by applying the liquid composition to the surface of the base film and then drying it. In particular, at least one of MCH, MEK and the like is preferable from the viewpoint of reducing the environmental load.

In the above liquid composition, polyethylene-based particles can be mixed, for example, about 1 to 150 parts by weight with respect to 100 parts by weight of the heat sealant, but the range is not particularly limited, and the type and coating of the heat sealant to be used are not particularly limited. It can be set as appropriate according to the construction conditions and the like. Further, the solid content of the liquid composition can be appropriately set in the range of, for example, about 5 to 80% by weight according to the coating conditions and the like, but is not limited thereto.

The method for applying the above liquid composition to the surface of the base film is not particularly limited, and known methods such as roll coating, various gravure coatings (for example, microgravure), bar coating, doctor blade coating, and brush coating are used. Can be adopted as appropriate.

After applying the liquid composition, drying can be carried out if necessary. The drying may be either natural drying or heat drying. In the case of heat drying, for example, it may be in the range of 120 ° C. or lower, and in particular, it can be set to about 60 to 100 ° C.

The method of laminating the sheet containing the heat sealant and the polyolefin-based particles of 2) above on the surface of the base film is not particularly limited, and is, for example, a dry laminating method, a non-solvent laminating method, an extrusion laminating method, a wet laminating method, and a heat laminating method. A known method such as a method can be appropriately adopted.

When the adhesion prevention layer is formed, the forming method thereof is not particularly limited. For example, a method including a step of applying a dispersion liquid obtained by dispersing water-repellent and / or oil-repellent particles in a solvent on a heat-sealing layer and then drying the particles can be preferably adopted.

The type of solvent used in the above dispersion is not particularly limited, and in addition to water, for example, alcohol-based (ethanol, etc.), cyclohexane, toluene, acetone, isopropyl alcohol, propylene glycol, hexylene glycol, butyl diglycol, pentamethylene. Organic solvents such as glycol, normal pentane, normal hexane and hexyl alcohol can be appropriately selected. At this time, a trace amount of a dispersant, a colorant, a sedimentation inhibitor, a viscosity regulator, or the like can be used in combination as long as the effects of the present invention are not impaired. The amount of the water-repellent and / or oil-repellent particles dispersed in the dispersion is not limited, and is usually about 10 to 100 g / L.

The method of applying the dispersion is not particularly limited. For example, known methods such as roll coating, gravure coating, bar coating, doctor blade coating, and brush coating can be adopted.

The drying after application may be either natural drying or forced drying (heat drying), but industrially, forced drying is preferable. The drying temperature is not limited as long as it does not affect the heat-bonded layer, but is usually in the range of 150 ° C. or lower, and can be, for example, about 70 to 120 ° C.

(3) Method of Use The packaging sheet of the present invention can be particularly suitably used as a constituent material of a packaging body. In particular, it can be suitably used for a package formed by heat-sealing. Regarding the composition of the package, etc., see 2. Will be explained in detail in.

2. Packaging body The present invention is a packaging body molded by the packaging sheet of the present invention, wherein (1) the packaging sheet is arranged so that the heat seal layer is inside the packaging body, and (2) the heat. Includes a packaging characterized in that the seal layers are joined together at least in part.

Further, the present invention also includes a product in which the contents are housed inside the package and at least a part of the heat seal layers are bonded to each other so that the contents are sealed in the package. do.

FIG. 2 shows an outline (cross-sectional view) of a product in which the contents are sealed in the package of the present invention. In addition, in FIG. 2, the illustration of the polyolefin-based particles is omitted. In the product 20 according to the present invention, the content 21 is sealed in the package 15 of the present invention. As the packaging body 15, two packaging sheets 10 of the present invention are prepared, arranged so that the heat-sealing layers 12 face each other, and heat-sealing is applied to the edges A and A'. As another embodiment, one packaging sheet 11 of the present invention is prepared, folded so that the heat-sealing layer is on the inner surface, and the edges thereof are joined by heat-sealing to form a packaging body. You may.

In FIG. 2, the package 15 is a package in a state of being sealed by a heat seal after containing the contents, but the present invention also includes a package before containing the contents. Therefore, a package (semi-finished product) in which an opening for accommodating the contents is left and the other portion is heat-sealed is also included in the present invention. For example, in FIG. 2, the edge portion A is heat-sealed in advance, and the edge portion A'is not heat-sealed so that the contents can be accommodated through the opening in the edge portion A'. The package is also included as the package of the present invention. In this case, the contents can be sealed by heat-sealing the edge portion A'after putting the contents in the packaging pair.

The term "sealed" in the present invention means a state in which the inside and the outside of the package are substantially shielded from each other. Therefore, for example, as long as the contents do not go out, a small amount of gas or the like is allowed to go in and out.

The shape of the wrapping body is not particularly limited, and for example, it can be suitably applied to a molded wrapping body, a strip-shaped side cover, a wrapping paper, a tray, a tube, and various bag bodies. The form of the bag is not particularly limited, and can be suitably used for any type such as a bottom seal bag, a side seal bag, a pillow bag, a gusset bag, and a pouch (standing pouch).

Examples and comparative examples are shown below, and the features of the present invention will be described more specifically. However, the scope of the present invention is not limited to the examples.

Example 1
A commercially available base film having a heat-sealing property with a thickness of 40 μm, commercially available polyethylene particles having an average particle size D50 of 12 μm, a melting point of 136 ° C., and a specific gravity of 0.94, and a coating mainly composed of a commercially available polyolefin resin. Agents (heat seal coating agent, solid content 20% by weight) were prepared respectively.
As the base film, the surface of the polypropylene resin-containing layer was further corona-treated in a laminated film in which a polypropylene resin-containing layer for imparting heat-sealing property was formed on one side of a biaxially stretched polypropylene film (OPP). (Hereinafter referred to as "HS-OPP") was used.
10 parts by weight of polyethylene particles are mixed and dispersed in 90 parts by weight of the coating agent, and this is coated on the polypropylene resin-containing layer surface of the base film with a bar coater and dried under the condition of 80 ° C. × 10 seconds to heat seal. A layer was formed. The target coating amount after drying at this time was set to 3.0 g / m ² . The laminate thus obtained was used as a packaging film.

Example 2
A packaging sheet was obtained in the same manner as in Example 1 except that commercially available polyethylene-based particles having an average particle size D50 of 30 μm, a melting point of 136 ° C., and a specific gravity of 0.94 were used instead of the polyethylene-based particles.

Example 3
A packaging sheet was obtained in the same manner as in Example 1 except that commercially available polypropylene particles having an average particle size D50 of 20 μm, a melting point of 155 ° C., and a specific gravity of 0.94 were used instead of the polyethylene particles.

Example 4
The same as in Example 1 except that a commercially available resin coating agent (a coating agent containing a mixture of an acrylic resin and a copolymer of vinyl chloride / vinyl acetate copolymer as a resin component) was used instead of the above coating agent. I got a packaging sheet.

Example 5
After producing the laminate in the same manner as in Example 1, a coating film containing silica fine particles was formed on the surface of the heat seal layer of the laminate to obtain a packaging sheet having an adhesion prevention layer. In order to form the coating film, a dispersion obtained by dispersing 1 part by weight of silica particles (AEROSIL "R812S" manufactured by Nippon Aerosil Co., Ltd.) with respect to 100 parts by weight of ethanol was used. The obtained dispersion was applied to the surface of the heat-sealed layer of the laminate with a bar coater, and then dried under the conditions of 80 ° C. × 10 seconds. The dispersion liquid was applied so that the amount of application after drying was about 0.3 g / m ^2.

Example 6
Instead of the polyethylene-based particles, commercially available polyethylene-based particles having an average particle size D50 of 30 μm, a melting point of 136 ° C., and a specific gravity of 0.94 are used, and the base film has a commercially available heat-sealing property of 30 μm in thickness. A packaging sheet was obtained in the same manner as in Example 1 except that a polyethylene terephthalate film (a film in which a polyester resin layer was co-extruded and laminated on one side of a PET film) was used.

Example 7
Instead of the polyethylene-based particles, commercially available polyethylene-based particles having an average particle size D50 of 30 μm, a melting point of 136 ° C., and a specific gravity of 0.94 are used, and a commercially available biaxially stretched polyethylene terephthalate having a thickness of 12 μm is used as a base film. The same as in Example 1 except that a laminate (12PET / D / 30LDPE) obtained by dry-laminating a film and a commercially available polyethylene film (low density polyethylene) having a thickness of 30 μm was prepared and coated on the polyethylene film side. And obtained a packaging sheet.

Example 8
Instead of the above polyethylene-based particles, commercially available polyethylene-based particles having an average particle size D50 of 30 μm, a melting point of 136 ° C., and a specific gravity of 0.94 are used, and a commercially available biaxially stretched polyethylene terephthalate having a thickness of 12 μm is used as a base film. A laminate (12PET / D / 30CPP) obtained by dry-laminating a film and a commercially available non-stretched polypropylene film (CPP film) having a thickness of 30 μm was prepared and coated on the polypropylene film side. A packaging sheet was obtained in the same manner.

Example 9
In place of the commercially available base film having a heat-sealing property of 40 μm, a commercially available biaxially stretched polypropylene film (OPP) having a thickness of 40 μm, which itself does not have a heat-sealing property, was used. A packaging sheet was obtained in the same manner.

Comparative Example 1
The base film used in Example 1 was prepared, and this was used as a packaging sheet.

Comparative Example 2
A commercially available embossed biaxially stretched polypropylene film (PP / PP film in which polypropylene resin was co-extruded and laminated as a heat seal layer on one side of the film) was used as a packaging sheet.

Comparative Example 3
A packaging sheet was obtained in the same manner as in Example 1 except that commercially available polyethylene-based particles having an average particle size D50 of 9 μm, a melting point of 105 ° C., and a specific gravity of 0.92 were used instead of the polyethylene-based particles. ..

Comparative Example 4
A packaging sheet was obtained in the same manner as in Example 1 except that commercially available polyethylene-based particles having an average particle size D50 of 60 μm, a melting point of 136 ° C., and a specific gravity of 0.94 were used instead of the polyethylene-based particles.

Comparative Example 5
Packaging in the same manner as in Example 1 except that commercially available crosslinked polymethylmethacrylate particles having an average particle size D50 of 20 μm, a melting point of 250 to 270 ° C., and a specific gravity of 1.2 were used instead of the polyethylene-based particles. I got a sheet.

Comparative Example 6
Instead of the polyethylene-based particles, commercially available crosslinked polymethylmethacrylate particles having an average particle size D50 of 50 μm, a melting point of 250 to 270 ° C., and a specific gravity of 1.2 were used, and the particles were packaged in the same manner as in Example 1. I got a sheet.

Comparative Example 7
Packaging in the same manner as in Example 1 except that commercially available crosslinked polyacrylic acid ester particles having an average particle size D50 of 30 μm, a melting point of 230 to 250 ° C., and a specific gravity of 1.1 were used instead of the polyethylene-based particles. I got a sheet.

Comparative Example 8
A packaging sheet was obtained in the same manner as in Example 1 except that commercially available crosslinked polystyrene particles having an average particle size D50 of 12 μm, a melting point of 250 to 270 ° C., and a specific gravity of 1.06 were used instead of the polyethylene-based particles. rice field.

Comparative Example 9
A packaging sheet was obtained in the same manner as in Example 1 except that commercially available crosslinked acrylic polymer particles having an average particle size D50 of 20 μm, a melting point of 340 ° C., and a specific gravity of 1.2 were used instead of the polyethylene-based particles. ..

Comparative Example 10
A packaging sheet was obtained in the same manner as in Example 1 except that commercially available silica particles having an average particle size D50 of 30 μm, a melting point of 1650 ° C., and a specific gravity of 2.0 were used instead of the polyethylene-based particles.

Comparative Example 11
A packaging sheet was obtained in the same manner as in Example 1 except that commercially available polyetheretherketone particles having an average particle size D50 of 20 μm, a melting point of 340 ° C., and a specific gravity of 1.32 were used instead of the polyethylene-based particles. rice field.

Test Example 1
The packaging sheets obtained in each Example and Comparative Example were evaluated for heat-sealing property, non-adhesiveness, etc., as shown below.

(1) Evaluation of heat-sealing property of each surface After heat-sealing the coated surfaces of each sample with a heat-sealing agent under ^{the conditions of 150 ° C. x 3 kg / cm 2} x 1 second using a hot plate of 20 mm x 60 mm, the seal is sealed. Three test pieces were prepared by slitting in a strip shape so as to have a width of 15 mm. The heat seal strength of each of these test pieces was measured with an autograph tester (EZ-LX manufactured by Shimadzu Corporation). More specifically, the seal strength (N) was subjected to a T peeling test at a speed of 100 mm / min, three points were measured for each sample, and the average overload strength (N) was determined. Considering the heat-sealing strength of practical packaging sheets, the surface-sealing strength is "○" for 4N / 15mm or more, "△" for 2N / 15mm or more and less than 4N / 15mm, and "x" for samples with 2N / 15mm or less. And said. The results are shown in Tables 1 and 2.

(2) Evaluation of anti-adhesion performance For evaluation of anti-adhesion, commercially available Western-style confectionery (“fluffy souffle whip custard” manufactured by Yamazaki Baking Co., Ltd.) (hereinafter referred to as “souffle”) is prepared and packaged in each. The samples were placed on a sheet and left separately for 24 hours at room temperature of 20 ° C. and humidity of 25% for 2 days and 4 days, respectively. After that, the souffle was removed, and the souffle deposits that were not visually confirmed on the packaging sheet even on the 4th day were marked with "○", and the souffle deposits were not confirmed on the 2nd day, but on the 4th day. Then, the sample in which the deposit was confirmed was marked with "Δ", and the sample with any souffle attached at 24 hours was marked with "x". The results are shown in Tables 1 and 2.

(3) Surface roughness (arithmetic mean roughness Ra)
Each sample was sampled to a size of 150 mm × 150 mm, and the arithmetic average roughness Ra (μm) was measured with a surface roughness meter (Surftest SV9633 / 3D manufactured by Mitutoyo Co., Ltd.) according to the JIS2001 standard. Specifically, as the measurement conditions, the measurement length was 17.5 mm, the evaluation length was 12.5 mm, the speed was 0.2 mm / s, the number of measurement points was 17,500, and the reference length was 2.5 mm. The results are shown in Tables 1 and 2.

As is clear from the results in Tables 1 and 2, heat seal containing polyolefin particles having an average particle size D50 of 10 μm or more and 50 μm or less and a melting point of 100 ° C. or more and 180 ° C. or less on at least one surface of the base film. It can be seen that the packaging sheet of the example in which the layers are laminated has better heat-sealing properties on the surface as compared with the comparative example, and even a soft content can effectively prevent adhesion to the packaging sheet.

Claims (7)

A packaging sheet containing a base film and a heat-sealing layer laminated on at least one surface of the base film.
(1) The heat-sealing layer contains a heat-sealing agent and polyolefin-based particles, and has a surface roughness Ra of 1.00 to 7.00 μm on the surface opposite to the base film.
(2) the polyolefin particles have an average particle diameter D50 is 10 to 50 [mu] m, Ri melting point of 100 to 180 ° C. der,
(3) The heat sealant contains a polyolefin resin and contains
(4) The heat seal layer is arranged so as to be the outermost layer.
A packaging sheet characterized by that. The packaging sheet according to claim 1, wherein the polyolefin-based particles have a specific gravity of 0.93 to 1.06. The packaging sheet according to claim 1, wherein the polyolefin-based particles contain at least one of a polyethylene-based resin and a polypropylene-based resin. The packaging sheet according to claim 1, wherein the base film is one or more of polypropylene-based film, polyethylene-based film, and polyester-based film. The packaging sheet according to claim 1, wherein the amount of the heat seal layer formed is 0.5 to 10.0 g / m ^2. A package formed by the packaging sheet according to any one of claims 1 to 5.
(1) The packaging sheet is arranged so that the heat seal layer is inside the packaging body.
(2) The heat seal layers are joined to each other at least in part.
A packaging body characterized by that. A product in which the contents are contained in the package according to claim 6 , and at least a part of the heat seal layers are bonded to each other so that the contents are sealed in the package.

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