JP7215469B2 - Heat-sealable resin film and its manufacturing method, laminate, packaging material, and forming roll - Google Patents

Description

TECHNICAL FIELD The present invention relates to a heat-sealable resin film and a method for producing the same, and more particularly, a heat-sealable resin film having an uneven structure on its surface, a method for producing the same, a laminate having a heat-sealable resin film, and a laminate. The present invention relates to a packaging material consisting of a body and a forming roll used when manufacturing the heat-sealable resin film.

In many product fields such as foods, beverages, pharmaceuticals, and chemicals, packaging materials have been developed according to their contents. In particular, as packaging materials for contents having viscous substances such as liquids, semi-solids, and gel-like substances, plastic materials that are excellent in water resistance, oil resistance, gas barrier properties, light weight, flexibility, design, etc. are used. It works for the protection of the contents required for the material.

As one of the functions of the packaging material, the function of preventing the contents from adhering to the inner surface of the packaging material, that is, from remaining inside the package is required. For example, it has been proposed to impart water and oil repellency to a substrate by providing a coating film containing metal oxide composite particles (see Patent Document 1). Also, it has been proposed to provide a heat-sealing resin layer containing hydrophobic fine particles such as silicone particles on one side of the substrate (see Patent Document 2).

Japanese Patent No. 5242841 JP 2013-18533 A

The present inventors have found that when a layer containing fine particles or the like is provided as the outermost layer of a packaging material as proposed in Patent Documents 1 and 2, the fine particles fall off and mix with the contents, or heat. We have found a problem that the sealing performance is impaired. Further, the inventors have found that even a thermoplastic resin film is not suitable for use as a lid material because its heat-sealing property is impaired.

The present invention has been made in view of the above-mentioned background art and newly discovered problems, and its object is to apply a surface treatment to the film surface without adding modifiers such as fine particles or lubricant components. Therefore, the object of the present invention is to provide a heat-sealable resin film capable of remarkably suppressing adhesion and residue even when the content is rich in oil.

That is, according to one aspect of the present invention,
A heat-sealable resin film having an uneven structure on its surface,
The uneven structure is formed by shaping with a forming roll having an uneven structure on the surface,
The resin film has a surface roughness Sa of 0.1 to 10 μm,
A heat-sealable resin film for use in a packaging bag is provided so that the surface provided with the uneven structure is on the innermost layer side.

In the aspect of the present invention, the maximum height Sz of the heat-sealable resin film is preferably 1 to 70 μm.

In the aspect of the present invention, the surface roughness Ra of the roll having the concave-convex structure is preferably 0.1 to 10 μm.

In the aspect of the present invention, the maximum height Rz of the roll having the concave-convex structure is preferably 1 to 70 μm.

In aspects of the invention,
The uneven structure is
A step of blowing first sandblast particles onto the roll surface to form unevenness;
A step of spraying second sandblast particles having an average particle size smaller than that of the first sandblast particles onto the surface of the roll having the unevenness to form unevenness finer than the unevenness. is preferred.

In the aspect of the present invention, it is preferable that the first sandblast particles have an average particle size of 10 to 300 μm.

In the aspect of the present invention, it is preferable that the second sandblast particles have an average particle size of 10 to 300 μm.

In the aspect of the present invention, the concave-convex structure is
A step of blowing sandblast particles onto the roll surface to form unevenness;
A step of forming a coating layer having a Vickers hardness higher than that of the roll surface on the roll surface;
It is preferable that the surface is formed by sandblasting, which includes a step of blowing the sandblast particles onto the surface of the roll having the uneven structure and the coating layer to form unevenness finer than the unevenness.

According to another aspect of the invention,
Provided is a laminate comprising a substrate layer and a layer comprising the heat-sealable resin film, wherein the surface having the uneven structure is the outermost surface.

In another aspect of the present invention, it is preferable to further have a barrier layer between the substrate layer and the layer composed of the heat-sealable resin film.

In another aspect of the present invention, it is preferable to further have a thermoplastic resin layer between the substrate layer and the layer made of the heat-sealable film.

Another aspect of the present invention provides a packaging material comprising the above laminate.

In yet another aspect of the invention,
A method for producing a heat-sealable resin film having an uneven structure on its surface,
A step of heating and melting a resin composition containing a thermoplastic resin;
A step of extruding the heat-melted resin composition;
A step of shaping the extruded resin composition using a molding roll having an uneven structure;
comprising
Provided is a method for producing a heat-sealable resin film, wherein the roll having the concave-convex structure has a surface roughness Ra of 0.1 to 10 μm.

In yet another aspect of the invention,
A forming roll having an uneven structure on its surface used for producing the heat-sealable resin film,
A forming roll is provided, characterized in that the surface roughness Ra is between 0.1 and 10 μm.

In another aspect of the present invention, the uneven structure is
A step of spraying first sandblast particles onto the roll surface to form unevenness;
A step of spraying second sandblast particles having an average particle size smaller than that of the first sandblast particles onto the roll surface having the unevenness to form unevenness finer than the unevenness. is preferred.

In another aspect of the present invention, the uneven structure is
A step of blowing sandblast particles onto the roll surface to form unevenness;
A step of forming a coating layer having a Vickers hardness higher than that of the roll surface on the roll surface;
A step of blowing the sandblast particles onto a roll surface having an uneven structure and a coating layer to form unevenness that is finer than the unevenness;
It is preferably formed by sandblasting comprising

In still another aspect of the present invention, the Vickers hardness of the coating layer is preferably 100 to 1300 Hv higher than the Vickers hardness of the forming roll surface.

According to the present invention, the film surface has an uneven structure and has a specific surface roughness Ra. A heat-sealable resin film is provided which can suppress the adhesion and residue thereof, and which does not use fine particles or the like and therefore does not slide down onto the contents, and which is excellent in terms of sanitation.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic cross section which showed one Embodiment of the manufacturing method of the heat-sealable resin film by this invention. FIG. 2 is a schematic cross-sectional view showing one embodiment of surface treatment of a forming roll. FIG. 2 is a schematic cross-sectional view showing one embodiment of surface treatment of a forming roll. 1 is a schematic cross-sectional view showing an embodiment of a laminate according to the present invention; FIG.

<Heat-sealable resin film>
The heat-sealable resin film according to the present invention has an uneven structure on its surface. The uneven structure on the film surface is formed by shaping with a forming roll having an uneven structure. By subjecting the film to such a surface treatment, it is possible to provide the film with a function of preventing contents, particularly oil-rich contents from remaining in the film. This is because the resin film has an uneven structure so as to have a surface roughness Ra within a specific range, and when used as a packaging material such as a packaging container, the contact area with the contents is small, so that the contents and the resin A gap is formed between the film and the resin film, and oil seeps out from the contents into this gap, forming an oil film between the contents and the resin film. When the contents are taken out, the contents slide on this oil film. This is thought to be due to the fact that they can move within the packaging material as much as possible.

The heat-sealable resin film according to the present invention preferably has a surface roughness Sa of 0.1 to 10 μm, more preferably 0.1 to 5 μm, still more preferably 0.1 to 3 μm. Also, the maximum height Sz of the surface having the uneven structure is preferably 1 to 50 μm, more preferably 1 to 40 μm, even more preferably 1 to 30 μm. If the surface roughness Sa and the maximum height Sz of the surface having the uneven structure are within the above ranges, the film can be imparted with an excellent function of preventing contents from remaining.

In the present invention, the surface roughness Sa is the arithmetic mean roughness, and Sz is the maximum height, both of which are values measured according to JIS B 0601. For example, it can be measured with a surface roughness measuring machine (manufactured by Tokyo Seimitsu Co., Ltd., trade name: Surfcom 1400G).

The heat-sealable resin film according to the present invention is preferably formed using a resin composition containing a thermoplastic resin as a main component. By using a thermoplastic composition resin as a main component, it is possible to impart sufficient heat-sealing performance to the resin film. Further, the content of the thermoplastic resin is preferably 30 to 100% by mass, more preferably 50 to 100% by mass, and 70 to 100% by mass with respect to the total mass of the resin composition. is more preferred.

Examples of thermoplastic resins include polyolefin resins such as polyethylene and polypropylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, ethylene-vinyl alcohol copolymer, polyacrylonitrile, polyamide, acrylic acid ester or methacrylic acid ester. and polyacetal, polyesters such as acrylic resins mainly composed of polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, and the like. These materials can be used singly or in combination. In the present invention, it is preferable to use a polyolefin resin as the thermoplastic resin.

Various additives other than the main component thermoplastic resin may be added to the resin composition as long as the properties thereof are not impaired. Additives include, for example, plasticizers, ultraviolet stabilizers, anti-coloring agents, matting agents, deodorants, flame retardants, weathering agents, antistatic agents, thread friction reducing agents, slip agents, release agents, anti- Oxidizing agents, ion exchange agents, color pigments, and the like can be added.
These additives are added in an amount of preferably 0.1 to 20% by mass, preferably 0.5 to 10% by mass, based on the total mass of the resin composition.

The resin composition preferably has a melt flow rate (MFR) of 0.1 to 100 g/10 minutes, more preferably 0.5 to 80 g/10 minutes, even more preferably 1 to 60 g/10 minutes. The melt flow rate is a value measured by method A under conditions of a temperature of 190° C. and a load of 21.18 N in the method specified in JIS K7210-1995. If the MFR of the resin composition is 1 g/10 minutes or more, the extrusion load during molding can be reduced. Moreover, if the MFR of the resin composition is 20 g/10 minutes or less, the mechanical strength of the resin film made of the resin composition can be increased.

The rugged structure on the film surface can be formed by pressure-molding a thermoplastic resin that has been heated and melted and extruded using rolls that shake the rugged structure. In the present invention, the uneven structure can be formed on the film surface at the same time as the film is formed by the manufacturing method described below. In this way, by forming the mold at the same time as forming the film, it is possible to simplify the manufacturing process and reduce the cost.

<Method for producing heat-sealable resin film>
A method for producing a heat-sealable resin film having an uneven structure on the surface includes the steps of heat-melting a resin composition containing a thermoplastic resin, extruding the heat-melted resin composition, and applying the extruded resin composition to the surface. and a step of pressure molding using a molding roll having an uneven structure.

The temperature for heating and melting the resin composition is preferably 100 to 400.degree. C., more preferably 120 to 350.degree. C., still more preferably 150 to 300.degree.

The forming roll having an uneven structure preferably has a surface roughness Ra of 0.1 to 15 μm, more preferably 0.5 to 10 μm, even more preferably 1 to 10 μm. Also, the maximum height Rz is preferably 0.1 to 70 μm, more preferably 0.5 to 60 μm, even more preferably 1 to 50 μm. If the surface roughness Ra and the maximum height Rz of the forming roll having the concave-convex structure are within the above ranges, the film can be imparted with an excellent function of preventing contents from remaining. The surface roughness Ra and the maximum height Rz of the forming roll can be measured, for example, with a surface roughness measuring machine (manufactured by Tokyo Seimitsu Co., Ltd., trade name: Surfcom 130A).

The material used for the forming roll is not particularly limited, but iron alloys, alloy steels, copper alloys, aluminum alloys, etc. can be used. Among these, iron alloys or alloy steels are preferable, and alloy steels are more preferable.

The Vickers hardness of the forming roll is preferably 50-1000 Hv, more preferably 100-600. The Vickers hardness can be measured using a Vickers hardness tester (Mitsutoyo Co., Ltd., repulsion paper container portable altimeter HH-411).

The concave-convex structure provided on the forming roll can be formed by surface treatment such as sandblasting, shotblasting, etching or engraving. Formation is preferred.

In one embodiment, the sandblasting includes a step of spraying first sandblasting particles onto the roll surface to form unevenness (first sandblasting), and second sandblasting particles having a smaller average particle size than the first sandblasting particles. is sprayed onto a roll surface having an uneven structure formed by spraying the first sandblast particles to form unevenness finer than the unevenness (second sandblasting).

The average particle size of the first sandblasting particles is preferably 10-300 μm, more preferably 30-200 μm, even more preferably 50-150 μm. The average particle size of the second sandblast particles is preferably 10 to 300 μm, more preferably 20 to 180 μm, even more preferably 30 to 130 μm.

The average particle size of the sandblasted particles is an average particle size measured by a particle size distribution measuring device using a laser diffraction scattering method, and is a volume average particle size calculated on a volume basis. Coulter LS230 manufactured by Beckman Coulter, Inc. can be used as the particle size distribution analyzer.

The blasting pressure in sandblasting is preferably 10 to 10,000 kPa, more preferably 50 to 5,000 kPa, even more preferably 100 to 1,000 kPa.

The forming roll is plated before sandblasting with the first sandblasting particles, after sandblasting with the first sandblasting particles and before sandblasting with the second sandblasting particles, and/or after sandblasting with the second sandblasting particles. A covering layer such as a layer, a resin layer or a coating layer may be provided. The thickness of the coating layer is preferably 1 to 100 (μm), more preferably 5 to 50 (μm), even more preferably 10 to 30 (μm).

The plating that constitutes the plating layer includes, for example, chrome plating, copper plating, nickel plating, zinc plating, and alloy plating of these. . The plated layer can be formed using a conventionally known method such as electroplating.

That is, as shown in FIG. 2, the forming roll 20 is first sandblasted using first sandblasting particles (not shown) to form the concave-convex structure 21 . Next, sandblasting is performed using second sandblasting particles (not shown) to form uneven structure 23 that is finer than uneven structure 21 .

In one embodiment, the sandblasting includes a step of spraying sandblast particles onto the roll surface to form unevenness (first sandblasting);
A step of providing a coating layer having a Vickers hardness higher than that of the roll surface on the roll surface;
A step (second sandblasting) of blowing the sandblast particles onto the surface of the roll having the uneven structure and the coating layer to form unevenness finer than the unevenness.

By providing a coating layer on the uneven structure of the roll surface between the first sandblasting treatment and the second sandblasting treatment, the hardness of the roll surface is increased, and the sandblasting particles used are used during the first sandblasting treatment. Even if the sandblasting particles are the same as those used in the first sandblasting treatment, it is possible to form a finer uneven structure than the uneven structure formed by the first sandblasting treatment.

The coating layer is not particularly limited as long as it has a higher hardness than the surface of the forming roll, but chrome plating, copper plating, nickel plating, zinc plating and alloy plating thereof are preferred. Moreover, the thickness of the coating layer may be within the numerical range described above.

The Vickers hardness of the coating layer is preferably 500-1500 Hv, more preferably 750-1100. The coating layer preferably has a Vickers hardness higher than that of the forming roll surface by 100 to 1300 Hv, more preferably 350 to 900 Hv.

The average particle size of the sandblast particles in this case is preferably 10 to 300 μm, more preferably 30 to 200 μm, even more preferably 50 to 150 μm.

The blasting pressure in the sandblasting treatment may be within the numerical range described above.

That is, as shown in FIG. 3, the forming roll 20 is first sandblasted using sandblast particles (not shown) to form an uneven structure 21 . Next, the surface of the forming roll on which the concave-convex structure 21 is formed is chrome-plated to form a coating layer 22 .
Further, sandblasting is performed again using the sandblasting particles (not shown) to form an uneven structure 23 that is finer than the uneven structure 21 .

In one embodiment of the method for producing a heat-sealable resin film according to the present invention, a film is formed by applying pressure while passing a heated and melted resin composition extruded from a T-die between a chill roll and a nip roll. Can be molded. In this embodiment, the chill roll corresponds to a forming roll having an uneven structure on its surface. An embodiment of a method for producing a heat-sealable resin film will be specifically described below with reference to the drawings.

As shown in FIG. 1 , first, a heat-melted resin composition 10 is extruded from a T-die 11 . Subsequently, the resin composition 10 is processed by blasting and pressurized when passing between a chill roll 12 having an uneven surface structure and a nip roll 13 to form a heat-sealable film 16. be. Simultaneously with the formation of the heat-sealable film, an uneven structure is formed on the film surface at the forming points 14 . The heat-sealable film 16 is peeled from the chill roll 12 at the peel point 15 .

<Laminate>
The laminate according to the present invention comprises a substrate layer and a layer made of the above heat-sealable resin film, and the surface having the concave-convex structure is the outermost surface. The laminate may further have a barrier layer between the substrate layer and the layer composed of the heat-sealable film, and may further have other layers such as a thermoplastic resin layer.

The structure of the laminate according to the present invention will be described with reference to the drawings. According to one aspect of the present invention, there is provided a laminate 30 having a substrate layer 31, a barrier layer 32, a thermoplastic resin layer 33, and a layer 34 made of a heat-sealable film in this order. .

<Base material layer>
The substrate layer constituting the laminate according to the present invention is not particularly limited in the present invention, but can be formed using a moldable resin. For example, low density polyethylene, medium density polyethylene, high density polyethylene, linear low density polyethylene, polypropylene, ethylene-vinyl acetate copolymer resin, ionomer resin, ethylene-acrylic acid copolymer resin, ethylene-ethyl acrylate copolymer resin. Coalescent resin, ethylene-methacrylic acid copolymer, ethylene-propylene copolymer, methylpentene resin, polybutene resin, acid-modified polyolefin resin, polyamide resin, polystyrene resin, low-crystalline saturated polyester or amorphous It can be formed using a polyester resin or the like. Among these resins, polyester-based resins, polybutylene terephthalate resins, polyethylene naphthalate resins, and particularly polyethylene terephthalate (PET) resins are preferable because of their good moldability. When a resin layer is formed as the substrate layer, the thickness of the substrate layer is preferably 4.5 to 100 μm, more preferably 12 to 50 μm, from the viewpoint of moldability. In order to improve the adhesiveness between these substrate layers and layers made of heat-sealable resin films, etc., surface activation such as corona treatment, flame treatment, plasma treatment, or flame treatment is applied to the surface. It is preferable to perform a hardening treatment.

A paper base material can also be used as the base material layer. In addition to non-coated paper such as kraft paper, fine paper, single-glazed kraft paper, pure white roll paper, glassine paper, and base paper for cups, synthetic paper that does not use natural pulp can also be used. As the paper substrate, for example, general lightly coated printing paper, coated printing paper, resin-coated paper, processed base paper, release base paper, double-sided coated release base paper, etc. are formed with a filling layer and a resin layer, which will be described later. A commercially available product can also be used. The paper used as the base material layer preferably has a basis weight of 15 to 300 g/m ² , more preferably 100 to 180 g/m ² .

<Barrier layer>
The barrier layer constituting the laminate according to the present invention is preferably made of an inorganic material or an inorganic oxide, and more preferably made of a deposited film of an inorganic material or an inorganic oxide, or a metal foil. The deposited film can be formed by a conventionally known method using a conventionally known inorganic substance or inorganic oxide, and the composition and formation method are not particularly limited.
When the laminate has the barrier layer, it is possible to impart or improve a gas barrier property that prevents permeation of oxygen gas and water vapor, and a light shielding property that prevents permeation of visible light, ultraviolet light, and the like. Note that the laminate may have two or more barrier layers. When there are two or more barrier layers, they may have the same composition or different compositions.

Examples of deposited films include silicon (Si), aluminum (Al), magnesium (Mg), calcium (Ca), potassium (K), tin (Sn), sodium (Na), boron (B), titanium (Ti ), lead (Pb), zirconium (Zr), yttrium (Y), or the like, or a deposited film of an inorganic oxide. In particular, as materials suitable for packaging materials (bags) and the like, vapor-deposited films of aluminum metal, or vapor-deposited films of silicon oxide, aluminum metal, or aluminum oxide are preferably used.

Inorganic oxides are represented by MO _X such as SiO _X and AlO _X (wherein M represents an inorganic element, and the value of X varies depending on the inorganic element). expressed. The range of values of X is 0 to 2 for silicon (Si), 0 to 1.5 for aluminum (Al), 0 to 1 for magnesium (Mg), 0 to 1 for calcium (Ca), Potassium (K) is 0 to 0.5, Tin (Sn) is 0 to 2, Sodium (Na) is 0 to 0.5, Boron (B) is 0 to 1,5, Titanium (Ti) can range from 0 to 2, lead (Pb) from 0 to 1, zirconium (Zr) from 0 to 2, and yttrium (Y) from 0 to 1.5. In the above, when X=0, it is a completely inorganic substance (pure substance) and not transparent, and the upper limit of the range of X is the fully oxidized value. Silicon (Si) and aluminum (Al) are preferably used for packaging materials, with silicon (Si) in the range of 1.0 to 2.0 and aluminum (Al) in the range of 0.5 to 1.5. values can be used.

In the present invention, the film thickness of the vapor-deposited film of the inorganic substance or inorganic oxide as described above varies depending on the type of inorganic substance or inorganic oxide used, but is for example about 50 to 2000 Å, preferably about 100 to 1000 Å. It is desirable to select and form arbitrarily within the range of.
More specifically, in the case of a vapor deposited film of aluminum, the film thickness is desirably about 50 to 600 Å, more preferably about 100 to 450 Å. Desirable film thickness is about 50 to 500 Å, more preferably about 100 to 300 Å.

Examples of methods for forming a deposited film include physical vapor deposition methods such as vacuum deposition, sputtering, and ion plating (physical vapor deposition, PVD), plasma chemical vapor deposition, thermochemical vapor deposition, and the like. A chemical vapor deposition method (Chemical Vapor Deposition method, CVD method) such as a chemical vapor deposition method and a photochemical vapor deposition method can be used.

Also, according to another aspect, the barrier layer may be a metal foil obtained by rolling a metal. A conventionally known metal foil can be used as the metal foil. Aluminum foil or the like is preferable from the viewpoint of gas barrier properties that prevent permeation of oxygen gas, water vapor, etc., and light-shielding properties that prevent permeation of visible light, ultraviolet rays, and the like.

<Layer made of heat-sealable resin film>
The layer composed of the heat-sealable resin film constituting the laminate according to the present invention is the outermost layer of the laminate, and the uneven structure of the heat-sealable resin film is located on the outermost surface.
Since the uneven structure of the heat-sealable resin film is positioned on the outermost surface, the laminate has a function of preventing contents from remaining in the laminate. The heat-sealable resin film is as described above. In addition, in order to improve the adhesion between the layer made of the heat-sealable resin film and the substrate layer, etc., the surface of the heat-sealable resin film having no uneven structure may be subjected to, for example, corona treatment, flame treatment, Surface activation treatment such as plasma treatment or flame treatment is preferably performed.

<Other layers>
The laminate according to the present invention may further have at least one other layer between the substrate layer and the barrier layer or between the barrier layer and the layer composed of the heat-sealable resin film. When two or more other layers are provided, they may have the same composition or may have different compositions. Other layers include, for example, a thermoplastic resin layer, an adhesive layer, and a printed layer.

Resins forming the thermoplastic resin layer include low-density polyethylene resin, medium-density polyethylene resin, high-density polyethylene resin, linear low-density polyethylene resin, and copolymerization with ethylene-α-olefin polymerized using a metallocene catalyst. Copolymer resin, ethylene-polypropylene copolymer resin, ethylene-vinyl acetate copolymer resin, ethylene-acrylic acid copolymer resin, ethylene-ethyl acrylate copolymer resin, ethylene-methacrylic acid copolymer resin, ethylene- Graft polymerization of unsaturated carboxylic acid, unsaturated carboxylic acid, unsaturated carboxylic acid anhydride, ester monomer to methyl methacrylate copolymer resin, ethylene-maleic acid copolymer resin, ionomer resin, polyolefin resin, or , a copolymerized resin, a resin obtained by graft-modifying maleic anhydride to a polyolefin resin, and the like can be used. These materials can be used singly or in combination.

The adhesive layer is a layer formed to bond any two layers by lamination, and is an adhesive layer or an adhesive resin layer. Examples of laminating adhesives include one-component or two-component curing or non-curing vinyl-based, (meth)acrylic-based, polyamide-based, polyester-based, polyether-based, polyurethane-based, epoxy-based, rubber-based, Other solvent-based, water-based, or emulsion-based laminating adhesives can be used. Examples of coating methods for the adhesive include direct gravure roll coating, gravure roll coating, kiss coating, reverse roll coating, fonten method, transfer roll coating, and other methods. The coating amount is preferably 0.1 g/m ² to 10 g/m ² (dry state), more preferably 1 g/m ² to 5 g/m ² (dry state). As the adhesive resin layer, for example, the above thermoplastic resin is used.

The printed layer is a layer provided for imparting design properties such as characters, information, patterns, and pictures to the laminate. The print layer can be formed using a conventionally known pigment or dye colorant, and the formation method is not particularly limited. For example, inorganic pigments such as titanium white, zinc white, rouge, vermillion, ultramarine blue, cobalt blue titanium yellow, yellow lead, carbon black, etc., isoindolinone yellow, Hansa yellow A, quinacridone red, permanent red 4R, phthalocyanine blue, indus Organic pigments (including dyes) such as Renblue RS and aniline black, metal pigments made of metal powders such as aluminum and brass, titanium dioxide-coated mica, pearls made of foil powder such as basic lead carbonate It can be formed by ink using a coloring agent such as a pigment or a fluorescent pigment.

<Packaging material>
A packaging material according to the present invention comprises the laminate described above. Specifically, it can be used for lids, packaging containers, and the like. By forming the packaging material so that the concave-convex structure of the heat-sealable resin film is positioned on the inner surface of the packaging material (on the side of the contents), it is possible to prevent the contents from adhering to or remaining on the inner surface of the packaging material.

<Surface treatment A of forming roll>
The surface of an SCM forming roll (manufactured by Kure Chrome Co., Ltd.) having a diameter of 400 mm and a face length of 500 mm was first sandblasted with emery sand having an average particle size of 165 μm to form an uneven structure. Next, the surface of the forming roll on which the uneven structure is formed is subjected to a second sand blast with diamond sand having an average particle size of 100 μm (a value smaller than that of the first diamond sand) to form a finer uneven structure than the uneven structure. formed. The forming roll A thus obtained had a surface roughness Ra of 8.7 μm and a maximum height Rz of 53.9 μm.

<Surface treatment B of forming roll>
The surface of an SCM forming roll (manufactured by Kagaku Chrome Co., Ltd.) having a diameter of 400 mm and a face length of 500 mm, Vickers hardness: 500) was first sandblasted with emery sand having an average particle size of 90 μm to form an uneven structure. rice field. Next, a 30 μm-thick chromium plating layer (Vickers hardness: 900) was formed on the surface of the forming roll by electrolytic plating. Further, the surface of the forming roll provided with the plated layer was subjected to a second sandblasting with the sandblasting particles used in the first sandblasting to form a finer uneven structure than the uneven structure. The forming roll thus obtained had a surface roughness Ra of 3.8 μm and a maximum height Rz of 30.5 μm.

Example 1
<Production of heat-sealable resin film>
Polypropylene resin (MFR = 6.5, manufactured by Japan Polypropylene Co., Ltd., trade name: Novatec FW4BT) was used to form a film at 280°C with a laboratory three-layer cast film-forming machine equipped with the molding roll A as a chill roll. to obtain a film with a thickness of 50 μm. The obtained film had a surface roughness Sa of 1.0 μm and a maximum height Sz of 7.5 μm.

<Production of packaging material>
The surface of the obtained heat-sealable resin film having no uneven structure was subjected to corona treatment, and the corona-treated surface of a 12 μm PET film (manufactured by Toyobo Co., Ltd., trade name: E5102) was subjected to two-component curing polyester adhesive. Agent (manufactured by Rock Paint Co., Ltd., trade name: RU004/H-1, coating amount: 3.5 g/m ² ) is applied, the corona-treated surfaces are dry-laminated, and PET film/adhesive/heat seal is applied. A laminated film composed of a flexible resin film was obtained. Furthermore, the layers of the heat-sealable resin films of these two laminated films were placed face to face to prepare a 4-sided pouch having outer dimensions of 150 mm x 120 mm, a sealing width of 10 mm, and one direction being unsealed. The resulting laminate was cut into two sheets of 150 mm × 120 mm in size, arranged so that the layers made of heat-sealable resin films face each other, and thermocompression bonded with a width of 10 mm on two vertical sides and one horizontal side (condition 210 °C, 1 kg/ ^cm2 , 11 seconds) to obtain a packaging material (food packaging bag).

Example 2
A film was formed in the same manner as in Example 1, except that the forming roll A was changed to the forming roll B, and then a packaging material was obtained. The resulting film had a thickness of 70 μm, a surface roughness Sa of 0.8 μm, and a maximum height Sz of 6.2 μm.

Comparative example 1
A film was formed in the same manner as in Example 1, except that the forming roll was changed to a forming roll having a surface roughness Ra of 0.05 μm and a maximum height Rz of 0.8 μm, and then a packaging material was obtained. The obtained film had a surface roughness Sa of 0.02 μm and a maximum height Sz of 0.5 μm.

Comparative example 2
A film was formed in the same manner as in Example 1 except that the sandblasting treatment using the second sandblasting particles was not performed, and the surface roughness Ra of the roll used was changed to 11 μm and the maximum height Rz was changed to 80 μm. , obtained the packaging material. The obtained film had a surface roughness Sa of 6.9 μm and a maximum height Sz of 54.5 μm.

<Performance evaluation of packaging materials>
The packaging materials obtained in the above Examples and Comparative Examples were mixed with Chinese seasoning (cooked meat: ingredients: soy sauce, soybean oil, vegetables (garlic, ginger), sugar, apple juice, tochi, soybean miso, sweet soy sauce, mashed potato, doubanjiang, fermented seasoning, starch, salt, chicken extract, pork extract, seasoning (amino acid), paste (xanthan), caramel pigment, acidulant, etc.), and the opening side is heat-pressed (Condition 210 ° C., 1 kg/cm ² , 1 second), and retort sterilization was performed at 120° C. for 30 minutes. After implementing retort sterilization, it left still at normal temperature (24 degreeC) for 1 day. After standing still, one short side of the packaging material was cut with a cutter, and the contents were taken out from the packaging material. The ease of taking out the contents from each packaging material was evaluated according to the following criteria. Table 1 shows the evaluation results.
<Evaluation Criteria>
○: 90% or more of the contents of the pouch slid down in less than 30 seconds.
Δ: 90% or more of the contents of the pouch slid down within 30 to 1 minute.
x: 90% or more of the contents of the pouch slid down in 1 minute or longer.

10: Resin composition 11: T-die 12: Chill roll 13: Nip roll 14: Shaping point 15: Peeling point 16: Heat-sealable film 20: Molding roll 21: Concavo-convex structure 22: Coating layer 23 Fine concavo-convex structure 40: Lamination Body 41 Base layer 42: Barrier layer 43: Thermoplastic resin layer 44: Layer made of heat-sealable resin film

Claims (4)

A packaging material comprising a laminate,
The laminate has a substrate layer, a printed layer, and a layer made of a heat-sealable resin film in this order ,
The heat-sealable resin film is a heat-sealable resin film having an uneven structure on its surface (provided that the surface of the heat-sealable resin film consists of a smooth surface and convex portions, and the number of convex portions is 1 mm ² 10 to 300 pieces per surface, and the shape of the convex portion has an arithmetic average roughness Ra of 0.4 to 3.0 μm, a maximum height Ry of 3.0 to 17.0 μm, and a ten-point average roughness Rz of 3.0 μm. excluding resin films that are 0 to 15.0 μm),
The surface roughness Sa of the surface having the uneven structure of the resin film is 0.8 to 3 μm, the maximum height Sz of the surface having the uneven structure of the resin film is 6.2 to 30 μm,
The heat-sealable resin film is a polypropylene resin film,
In the packaging material, the surface having the uneven structure of the heat-sealable resin film is located in the innermost layer,
Packaging material for food containing oil. The packaging material according to claim 1, wherein the laminate further has an adhesive layer between the base material layer and the layer made of the heat-sealable resin film. The packaging material according to claim 1 or 2, wherein the food is Chinese seasoning. The packaging material according to any one of claims 1 to 3, which is a lid material or a packaging container.

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