JP6874451B2 - Lid material and packaging container using the lid material - Google Patents

Description

The present invention relates to a lid material and a packaging container using the lid material, and more specifically, an easy peel lid material and the lid used for closing an opening of a plastic or paper container such as a tray or a cup. It relates to a packaging container made of wood. Furthermore, the present invention relates to a lid material for packaging a spice and a solid roux containing a large amount of spices such as curry and stew, and a packaging container using the lid material.

Conventionally, a bottom material having a storage portion for contents and a lid material for closing and sealing the opening have been used. For example, as a form for packaging solid roux of curry or stew, a packaging container in which an easy peel lid material made of a laminated film is heat-sealed at the opening of a plastic tray (bottom material) provided with a roux storage portion is used. There is.

In the lid material used for such packaging containers, easy peeling property, that is, easy opening property, gas barrier property against oxygen and water vapor, fragrance retention property, film residue at the time of opening, film tearing, and sufficient interlayer adhesive strength to prevent breakage. And tensile strength is required.

In recent years, it is thin and resource-saving, and there are few film bonding processes due to environmental considerations such as resource saving, weight reduction of packaging materials, VOC reduction by simplifying the manufacturing process, and CO _{2 reduction.} The use of laminated films is required.

In response to these demands, a lid material made of a laminated film in which three films of a gas barrier film, a reinforcing film and an easy peeling sealant film are laminated via a dry laminate adhesive or an adhesive resin is widely used. (Patent Document 1). Further, in order to further reduce the thickness and weight of the three-layer laminated film and reduce the film bonding process, there is also a demand for omitting the reinforcing film to form a two-layer structure. However, the lid material made of such a two-layer laminated film has a problem that when it is peeled off from a bottom material such as a tray, the film breaks or delamination occurs and a film residue is generated. ..

Japanese Unexamined Patent Publication No. 2013-133147

The present invention has been made to solve such a problem. Therefore, although the lid material is environmentally friendly from the viewpoint of weight reduction and simplification of the manufacturing process, the easy peeling property and gas barrier property required as the lid material, A lid material having a fragrance-retaining property and which does not cause film residue, film tearing or breakage when opened, and a packaging container using the lid material, and in particular, a large amount of spices or spices such as curry roux are contained. It is an object of the present invention to provide a lid material for accommodating the contents and a packaging container using the lid material.

As a result of various studies, the present inventors have at least two or three or more kinds of resins that are incompatible with each other, the base material layer having a gas barrier layer, the adhesive resin layer containing an acid-modified polyolefin resin, and the resin. It has been found that a film-like lid material having a sealant layer having an easy peel layer made of a blended polymer containing the above-mentioned object achieves the above object.

The present invention is characterized by the following points.
1. 1. A film-like lid material having at least a base material layer, a sealant layer, and an adhesive resin layer for adhering the base material layer and the sealant layer, and the base material layer has a gas barrier layer. The adhesive resin layer is a melt-extruded layer formed by using an acid-modified polyolefin resin composition, and the sealant layer has a polyethylene-based resin layer and an easy peel layer exposed on the surface. The easy peel layer is a lid material made of a blended polymer containing two or more kinds of resins that are incompatible with each other.
2. The spice-resistant lid material according to 1 above, for a packaging container for containing a spice or a content containing a large amount of spice.
3. 3. The lid material according to 1 or 2 above, wherein the gas barrier layer has a silicon oxide vapor deposition layer or an aluminum oxide vapor deposition layer deposited on a plastic film.
4. The gas barrier layer further has a gas barrier resin coating layer, and the gas barrier resin coating layer has a thickness of 0.01 to 100 μm and is represented by the following general formula (1). Any of the above 1 to 3 which is a coating film layer formed by producing a hydrolyzed polycondensate by a sol-gel method in a gas barrier resin composition containing an alkoxide of more than one species and a water-soluble polymer having a hydroxyl group. The lid material described in Crab.
R ¹ _n M (OR ² ) _m (1)
(In the formula, M represents a metal atom, R ¹ and R ² represent an organic group having 1 to 8 carbon atoms, n is an integer of 0 or more, m is an integer of 1 or more, and n + m is M. Represents valence)
5. The adhesive resin layer has a thickness of 5 to 25 μm, a solvent content of 0% by mass or 1% by mass or less in the adhesive resin layer, and the acid-modified polyolefin resin composition at 190 ° C. The lid material according to any one of 1 to 4 above, wherein the MFR value is 3 to 100 g / 10 minutes.
6. The lid material according to any one of 1 to 5 above, wherein the polyethylene-based resin layer has a multi-layer structure having a high-density polyethylene layer.
7. The polyethylene-based resin layer has a multi-layer structure having a low-density polyethylene layer and a high-density polyethylene layer, and the high-density polyethylene layer exists between the low-density polyethylene layer and the easy peel layer. The lid material according to any one of 1 to 5 above.
8. The lid material according to any one of 1 to 7 above, wherein the polyethylene-based resin layer has a thickness of 5 to 70 μm, and the easy peel layer has a thickness of 1 to 20 μm.
9. 7. The lid material according to 7 above, wherein the low-density polyethylene layer has a thickness of 2.5 to 35 μm, and the high-density polyethylene layer has a thickness of 2.5 to 35 μm.
10. The lid material according to any one of 1 to 9 above, wherein the acid-modified polyolefin resin is at least a copolymer of an alkene, a (meth) acrylic acid ester, and an unsaturated carboxylic acid.
11. 10. The lid according to 10 above, wherein the content of the residue derived from the unsaturated carboxylic acid in the copolymer is 0.05% by mass or more and less than 1.0% by mass in the total amount of the copolymer. Material.
12. 10. The lid material according to 10 or 11 above, wherein the content of the residue derived from the (meth) acrylic acid ester in the copolymer is 5 to 40% by mass in the total amount of the copolymer.
13. The lid material according to any one of 1 to 12 above, wherein the blend polymer is a blend polymer containing at least a polyethylene resin and a polypropylene resin and having a sea-island structure.
14. The lid material according to 13 above, wherein the mass ratio of the polyethylene-based resin to the polypropylene-based resin of the blend polymer is polyethylene-based resin / polypropylene-based resin = 10/90 to 50/50.
15. The lid material according to any one of 1 to 12 above, wherein the blend polymer is a blend polymer containing at least a polyethylene resin and a polystyrene resin and having a sea-island structure.
16. The lid material according to 15 above, wherein the mass ratio of the polyethylene-based resin to the polystyrene-based resin of the blend polymer is polyethylene-based resin / polystyrene-based resin = 20/80 to 50/50.
17. A packaging container formed of the lid material according to any one of 1 to 16 and a bottom material made of polypropylene-based resin or polyethylene-based resin, wherein the sealant layer of the lid material and an opening of the bottom material. A packaging container in which the peripheral flange of the part is heat-sealed.

The present invention has a small-layer structure, is a lid material that is environmentally friendly due to weight reduction and simplification of the manufacturing process, and has the easy peeling property, gas barrier property, and fragrance retention property required as a lid material, and at the time of opening. It is possible to provide a lid material that does not cause film residue, film tearing or breakage, and a packaging container using the lid material. The lid material of the present invention and the packaging container using the lid material have high content resistance, and even when a content containing a large amount of spices such as spices and curry roux is packaged, heat due to volatile substances generated from the spices is generated. There is little deterioration of the seal layer, and it is possible to maintain the sealed state for a long period of time.

It is the schematic sectional drawing which shows an example about the layer structure of the lid material of this invention. It is the schematic sectional drawing which shows an example about the layer structure of the packaging container of this invention.

The present invention described above will be described in more detail below.

<Layer structure of the laminate for packaging material of the present invention>
FIG. 1 is a schematic cross-sectional view showing an example of the layer structure of the lid material of the present invention. As shown in FIG. 1, the lid material of the present invention is formed by laminating a base material layer 1, an adhesive resin layer 2, and a sealant layer composed of a polyethylene resin layer 3a and an easy peel layer 3b. Is.

Although not shown in the figure, in detail, the base material layer 1 has a gas barrier layer, and the easy peel layer 3b is a blend polymer containing two or more kinds of resins that are incompatible with each other. It consists of.

Further, FIG. 2 shows a packaging container using the lid material, and the easy peel layer 3b is adhered to the flange portion of the bottom material 4 by a heat seal.

Next, each layer will be described.

<Base layer>
In the present invention, any gas barrier film constituting a normal packaging material can be appropriately used as the base material layer.

In the present invention, the gas barrier film is not particularly limited, and a known or commercially available gas barrier film can be applied as long as it can suppress oxygen permeation and water vapor permeation from the outside world. Specific examples of the gas barrier film include polyethylene terephthalate (PET), polybutylene terephthalate, polyvinyl chloride, polyvinylidene chloride, polyethylene naphthalate, polypropylene (PP), polyamide, polyimide, polyvinyl alcohol, and ethylene / vinyl alcohol. A resin film made of a resin such as a polymer or a vapor-deposited film can be used, but the present invention is not limited thereto. Among the above films, it is particularly preferable to use a vapor-deposited film from the viewpoint of gas barrier property and interlayer adhesion strength with the adhesive resin layer.

In the present invention, the vapor-deposited film is a film in which a vapor-deposited film made of an inorganic substance or an inorganic oxide is provided on at least one surface of a plastic film.

Here, as the plastic film, a resin film having excellent chemical or physical strength, which can withstand the conditions for forming a vapor-deposited film, and can be held satisfactorily without impairing the characteristics of the vapor-deposited film is used. Can be done. For example, a polyolefin resin film such as polypropylene (PP) and polyethylene (PE), a polyester film such as polyethylene terephthalate (PET) and polyethylene naphthalate, and a polyamide such as nylon 6, nylon 66 and polymethoxylylen adipamide (MXD6). Examples thereof include films and sheets made of various resins such as films and polyimide films. A uniaxial or biaxially stretched polyester film or a uniaxial or biaxially stretched polyamide film is preferably used because of its excellent mechanical strength and pinhole resistance.

When providing a vapor deposition film on a plastic film, pretreatment such as corona discharge treatment, ozone treatment, low temperature plasma treatment using oxygen gas or nitrogen gas, glow discharge treatment, oxidation treatment with chemicals, etc. is performed as necessary. It can be applied arbitrarily. Further, the surface pretreatment is carried out in order to improve the adhesion between the plastic film and the vapor-deposited film, but as another method for improving the adhesion, for example, on the surface of the plastic film in advance. , Primer coating agent layer, undercoat layer, anchor coating agent layer and the like can be arbitrarily formed.

Examples of the vapor deposition film include silicon (Si), aluminum (Al), magnesium (Mg), calcium (Ca), potassium (K), tin (Sn), sodium (Na), boron (B), and titanium (Ti). ), Lead (Pb), zirconium (Zr), yttrium (Y) and other inorganic substances or inorganic oxide vapor deposition films can be used. In particular, those suitable for packaging materials include a thin-film film of aluminum metal or a thin-film film of silicon oxide or aluminum oxide.

Representation of the inorganic oxide, for example, SiO _X, as such AlO _X MO _X (In the formula, M represents an inorganic element, the value of X, varies each of an inorganic element range.) In expressed. The range of X values 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), and potassium (K). 0-0.5, tin (Sn) 0-2, sodium (Na) 0-0.5, boron (B) 0-1.5, titanium (Ti) 0-2, lead (Pb) ) Can take a value in the range of 0 to 1, zirconium (Zr) can take a value in the range of 0 to 2, and yttrium (Y) can take a value in the range of 0 to 1.5. In the above, when X = 0, it is a completely inorganic simple substance (pure substance) and is not transparent, and the upper limit of the range of X is the value when it is completely oxidized. Silicon (Si) and aluminum (Al) are preferably used as the packaging material, and silicon (Si) is in the range of 1.0 to 2.0 and aluminum (Al) is in the range of 0.5 to 1.5. It can be preferably used.

As a method for forming the vapor deposition film, a physical vapor deposition method (Physical Vapor Deposition method, PVD method) such as a vacuum vapor deposition method, a sputtering method and an ion plating method, or a plasma chemical vapor deposition method or a thermochemical vapor deposition method is used. Examples thereof include a method and a film forming method such as a chemical vapor deposition method (CVD method, CVD method) such as a photochemical vapor deposition method.

Further, the vapor deposition film may be composed of a single layer formed by one vapor deposition step, or may have a multilayer structure formed by repeating the vapor deposition step a plurality of times. In the case of a multi-layer structure, each layer may be made of the same material or different materials, may be formed by the same forming method, or may be formed by different forming methods. Good. For example, a thin-film film made of silicon oxide may be formed on a plastic film by a chemical vapor deposition method, and then a thin-film film made of aluminum oxide may be formed by a physical vapor deposition method.

The thickness of the entire layer can be appropriately set in the range of 1 to 200 nm, preferably 1 to 100 nm, more preferably 1 to 50 nm, and further preferably 1 to 30 nm. For example, if it exceeds 200 nm, the flexibility is lowered, the vapor-deposited film may be cracked by an external force such as bending or pulling after the film is formed, the transparency is lowered, and the stress of the material itself is increased. It is not preferable because it becomes large and colored. On the other hand, when the thickness of the thin-film deposition film is less than 1 nm, the transparency is good, but it is difficult to obtain a uniform layer, and it is difficult to sufficiently fulfill the gas barrier function.

Specifically, in the case of a thin-film aluminum film, the film thickness is preferably 1 to 60 nm, more preferably 1 to 40 nm. In the case of a thin-film film of silicon oxide or aluminum oxide, the film thickness is preferably 1 to 50 nm, more preferably 1 to 30 nm.

Hereinafter, as a preferred embodiment of the present invention, a silicon oxide vapor-deposited film will be described in more detail. The thin-film film (thin film) of silicon oxide is represented by a general formula: SiO _x (where x represents a number of 0 to 2), and the value of x is preferably 1.3 to 1.9. Further, the silicon oxide thin film is mainly composed of silicon oxide, and may further contain at least one kind of a compound composed of one kind of carbon, hydrogen, silicon or oxygen, or two or more kinds of elements by a chemical bond or the like. For example, when the compound having a CH bond, the compound having a Si—H bond, or the carbon unit is in the form of graphite, diamond, fullerene, etc., the raw material organic silicon compound or a derivative thereof can be further used. It may be contained due to chemical bonds or the like. For example, hydrocarbons having _{a CH 3} moiety, hydrosilica such as _{SiH 3} silyl and SiH ₂ silylene, and hydroxyl derivatives such as _{SiH 2 OH silanol can be mentioned.} The content of the above compound in the vapor-deposited film of silicon oxide is 0.1 to 50% by mass, preferably 5 to 20% by mass. When the silicon oxide thin film contains the above compound, it is preferable that the content of the compound decreases from the surface of the silicon oxide vapor-deposited film toward the depth direction.

As a result, the impact resistance and the like are enhanced by the above compounds on the surface of the silicon oxide vapor-deposited film, while the plastic film and the silicon oxide vapor-deposited film are formed at the interface with the plastic film because the content of the compound is small. The tight adhesion of the film becomes strong.

Examples of the organic silicon compound used as a raw material when forming a carbon-containing silicon oxide vapor deposition film as described above include 1,1,3,3-tetramethyldisiloxane and hexamethyldisiloxane (HMDSO). , Vinyltrimethylsilane, methyltrimethylsilane, hexamethyldisilane, methylsilane, dimethylsilane, trimethylsilane, diethylsilane, propylsilane, phenylsilane, vinyltriethoxysilane, vinyltrimethoxysilane, tetramethoxysilane, tetraethoxysilane, phenyltri Methoxysilane, methyltriethoxysilane, octamethylcyclotetrasiloxane and the like can be used.

In the present invention, by further providing the gas barrier resin coating layer as described below on the thin film, not only more excellent gas barrier property can be obtained, but also close adhesion with the adhesive resin layer described later will be obtained. Increases sex.

The gas barrier resin coating layer is formed by coating a gas barrier resin composition containing an alkoxide and a water-soluble polymer having a hydroxyl group on the vapor-deposited film.

The alkoxide used in the gas barrier resin composition is represented by the general formula (1).
R ¹ _n M (OR ² ) _m (1)
(However, in the formula, R ¹ and R ² represent an organic group having 1 to 8 carbon atoms, M represents a metal atom, n represents an integer of 0 or more, and m represents an integer of 1 or more. Represented, n + m represents the valence of M.)

As the metal atom M, silicon, zirconium, titanium, aluminum or the like can be used.

Specific examples of the organic group represented by R ¹ include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, an i-butyl group, a sec-butyl group, and t. -Butyl group, n-hexyl group, n-octyl group and other alkyl groups can be mentioned.

Specific examples of the organic group represented by R ² include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, a sec-butyl group and the like.

In the same molecule, these R ¹ and R ² may be the same or different.

In the present invention, as the alkoxide represented by the general formula (1), for example, an alkoxysilane in which M is Si can be used, and as the alkoxysilane, for example, tetramethoxysilane Si (OCH ₃ ) ₄ , Examples thereof include tetraethoxysilane Si (OC ₂ H ₅ ) ₄ , tetrapropoxysilane Si (OC ₃ H ₇ ) ₄ , and tetrabutoxysilane Si (OC ₄ H ₉ ) _4. The present invention is not limited thereto. Further, the alkoxide represented by the general formula (1) may be used alone or in combination of two or more.

Examples of the water-soluble polymer include polyvinyl alcohol-based resins and ethylene / vinyl alcohol copolymers. Specifically, polyvinyl alcohol, polyvinylpyrrolidone, starch, methylcellulose, carboxymethylcellulose, sodium alginate, or ethylene-. Examples thereof include vinyl alcohol copolymers, and ethylene-vinyl alcohol copolymers and polyvinyl alcohols are particularly preferable. As the water-soluble polymer having these hydroxyl groups, one type may be used alone, or two or more types may be used in combination. The present invention is not limited to the above specific examples.

The content of the water-soluble polymer in the gas barrier resin composition is preferably in the range of 5 to 500 parts by mass with respect to 100 parts by mass of the alkoxide represented by the general formula (1). In the above, if it exceeds 500 parts by mass, the brittleness of the formed gas barrier resin coating layer tends to increase, and the weather resistance and the like tend to decrease, which is not preferable.

As the polyvinyl alcohol, for example, one obtained by saponifying polyvinyl acetate can be used. Specific examples of polyvinyl alcohol include PVA110 manufactured by Kuraray Co., Ltd. (concentration = 98 to 99%, degree of polymerization = 1100), PVA117 (degree of polymerization = 98 to 99%, degree of polymerization = 1700), and PVA124 (consolidation). Degree = 98-99%, degree of polymerization = 2400), PVA135H (degree of polymerization = 99.7% or more, degree of polymerization = 3500), RS-110 (degree of polymerization = 99%, polymerization), which is an RS polymer manufactured by the same company. Degree = 1,000), Clarepovar LM-20SO (degree of polymerization = 40%, degree of polymerization = 2,000) manufactured by the same company, Gosenol NM-14 (degree of polymerization = 99%) manufactured by Nippon Synthetic Chemical Industry Co., Ltd. , Degree of polymerization = 1,400) and Gosenol NH-18 (degree of polymerization = 98-99%, degree of polymerization = 1700) and the like can be used.

Further, as the ethylene-vinyl alcohol copolymer, a saponified product of a copolymer of ethylene and vinyl acetate, that is, a product obtained by saponifying an ethylene-vinyl acetate random copolymer can be used. Such saponified products include partially saponified products in which tens of mol% of acetic acid groups remain, and completely saponified products in which only a few mol% of acetic acid groups remain or no acetic acid groups remain. To. Although not particularly limited, from the viewpoint of gas barrier properties, it is desirable to use one having a saponification degree of 80 mol% or more, more preferably 90 mol% or more, still more preferably 95 mol% or more.

The content of repeating units derived from ethylene in the above ethylene-vinyl alcohol copolymer (hereinafter, also referred to as "ethylene content") is usually 5 to 50 mol, which is the total number of repeating unit moles in the copolymer. %, Preferably 20 to 45 mol%.

Specific examples of the above ethylene-vinyl alcohol copolymer include Kuraray Co., Ltd., EVAL EP-F101 (ethylene content; 32 mol%), Nippon Synthetic Chemical Industry Co., Ltd., Soanol D2908 (ethylene content; 29 mol%). ) Etc. can be used.

The gas barrier resin composition can preferably further contain a silane coupling agent. As the silane coupling agent, known organic reactive group-containing organoalkoxysilanes can be used, but organoalkoxysilanes having an epoxy group are particularly preferable, and for example, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, or the like can be used. The above-mentioned silane coupling agent may be used alone or in combination of two or more. In the present invention, the silane coupling agent can be used in the range of 1 to 20 parts by mass with respect to 100 parts by mass of the alkoxide represented by the general formula (1).

The gas barrier resin coating layer is obtained by mixing an alkoxide and a water-soluble polymer represented by the general formula (1) and, if necessary, a silane coupling agent, and if necessary, water, an organic solvent and the like. A layer in which a gas barrier resin composition prepared by adding a sol-gel method catalyst is applied onto a vapor-deposited film and contains a hydrolyzed polycondensate produced by the sol-gel method.

As the organic solvent used in the preparation of the above gas barrier resin composition, for example, methyl alcohol, ethyl alcohol, isopropyl alcohol, n-propyl alcohol, n-butanol and the like can be used.

As the sol-gel method catalyst, use a tertiary amine, particularly N, N-dimethylbenzylamine, tripropylamine, tributylamine, trypentylamine, etc., which is substantially insoluble in water and soluble in an organic solvent. Can be done. In particular, N, N-dimethylbenzylamine is preferable. The content of these sol-gel catalysts is 0.01 to 1.0 parts by mass, particularly 0.02, with respect to 100 parts by mass of the total amount of the alkoxide represented by the general formula (1) and the silane coupling agent. It is preferably ~ 0.04 parts by mass.

An acid can also be used as the sol-gel process catalyst. Examples of the acid preferably used include mineral acids such as sulfuric acid, hydrochloric acid and nitric acid, and organic acids such as acetic acid and tartaric acid. The content of such an acid is preferably 0.001 to 0.05 mol%, more preferably 0.001 to 0.05 mol%, based on the total molar amount of the alkoxide represented by the general formula (1) and the silane coupling agent. It is 0.01 to 0.03 mol%.

By forming, for example, a chemical bond, a hydrogen bond, or a coordination bond by hydrolysis / cocondensation between the vapor-deposited film and the gas barrier resin coating layer, the adhesion between these two layers is improved, and a synergistic effect is obtained. Therefore, a better gas barrier effect can be exhibited.

Examples of the method for applying the gas barrier resin composition include roll coating such as a gravure roll coater, spray coating, dipping, brushing, bar coating, and application means such as an applicator. Form the required thickness. The gas barrier resin coating layer may be one layer having the same composition or a composite polymer layer in which two or more layers having different compositions are laminated.

The thickness of the gas barrier resin composition after drying is 0.01 to 100 μm, preferably 0.1 to 50 μm, and more preferably 0.3 to 10 μm. If the thickness after drying exceeds 100 μm, cracks are likely to occur, which is not preferable.

<Adhesive resin layer>
In the present invention, the adhesive resin layer is a layer formed by melt-extruding an acid-modified polyolefin resin composition. The acid-modified polyolefin-based resin contained in the acid-modified polyolefin-based resin composition includes, for example, an alkene-unsaturated carboxylic acid obtained by copolymerizing an unsaturated carboxylic acid with an alkene-or (meth) acrylic acid ester, or (meth). Examples thereof include a ternary copolymer of an acrylic acid ester-unsaturated carboxylic acid and a ternary copolymer of an alkene- (meth) acrylic acid ester-unsaturated carboxylic acid. The form of copolymerization may be any of random copolymerization, alternate copolymerization, block copolymerization, and graft copolymerization.

This acid-modified polyolefin-based resin composition exhibits high interlayer adhesion strength with both films by melt-extruding and sandwich-laminating between the gas barrier film and the sealant film described later.

In particular, when the acid-modified polyolefin-based resin composition is melt-extruded onto the surface of the vapor-deposited film, the surface of the gas barrier resin coating layer, and the surface of the polyethylene-based resin of the sealant layer described later, extremely high interlayer adhesion strength is obtained. Is demonstrated.

This extremely high interlayer adhesion strength is obtained by chemically or physically bonding functional groups such as carboxyl groups of the acid-modified polyolefin resin to the surface of the layer to be bonded.

Therefore, an anchor coating agent layer or the like provided in advance on the base material layer or the sealant layer at the time of ordinary sandwich laminating is not always necessary, and further, the acid-modified polyolefin resin composition uses an organic solvent. do not need. Therefore, according to the present invention, the lamination strength (adhesive strength) between layers is lowered due to the elution of residual solvents and low molecular weight substances derived from anchor coating agents and organic solvents, and the deterioration of the adhesive resin layer over time due to them. It is possible to avoid the problem, and it can be applied to a wide variety of applications.

In one aspect of the present invention, the acid-modified polyolefin-based resin composition may consist only of the acid-modified polyolefin-based resin, and in another embodiment, the acid-modified polyolefin-based resin composition may be an acid-modified polyolefin-based resin. In addition, even if it further contains a resin for modification such as a polyolefin resin, a polyamide resin, a polyester resin, an ethylene-vinyl alcohol copolymer, polyvinyl chloride, and polyvinylidene chloride, if desired. Good. However, the amount of the unsaturated carboxylic acid component and the amount of the (meth) acrylic acid ester component in the acid-modified polyolefin resin composition are adjusted so as to be within the specified ranges described later.

Furthermore, for example, workability, heat resistance, weather resistance, mechanical properties, dimensional stability, antioxidant properties, slipperiness, releasability, flame retardancy, antifungal properties, electrical properties, strength, etc. have been improved and modified. Various plastic compounding agents, additives, and the like can be added for the purpose of the above, and the amount of the addition can be from a very small amount to several tens of percent, depending on the purpose. As general additives, for example, lubricants, cross-linking agents, antioxidants, ultraviolet absorbers, light stabilizers, fillers, reinforcing agents, antistatic agents, pigments and the like can be used.

Examples of the alkene as a raw material of the acid-modified polyolefin resin include ethylene, propylene, butene, isobutene, pentene, hexene and the like, and ethylene is particularly preferably used.

The raw material (meth) acrylates include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, and (meth). ) Trt-butyl acrylate, ethyl-2-hexyl (meth) acrylate, cyclohexyl (meth) acrylate and the like, preferably methyl acrylate, ethyl acrylate, butyl acrylate, more preferably methyl acrylate. used.

Examples of the unsaturated carboxylic acid as the raw material include acrylic acid, methacrylic acid, etacrilic acid, fumaric acid, maleic acid, citraconic acid, itaconic acid, derivatives thereof, for example, acid anhydrides, esters, amides, imides and the like. Examples thereof include monomethyl maleate, maleic anhydride, citraconic anhydride, itaconic anhydride and the like, and in particular, unsaturated dicarboxylic acid and maleic anhydride are preferably used.

These alkene, (meth) acrylic acid ester, and unsaturated carboxylic acid may be used alone or in combination of two or more. It is also possible to use other copolymerizable monomers in combination as long as the performance of the present invention is not impaired.

Preferred copolymers include, for example, a ternary copolymer resin of ethylene- (meth) acrylic acid ester-maleic anhydride.

The acid-modified polyolefin resin can be produced by various conventional methods.

For example, a polymer synthesized from an alkene is dry-blended with an unsaturated carboxylic acid, and if necessary, an organic peroxide and a radical generator at a blending ratio as required, using a Henschel mixer or the like. The acid-modified polyolefin resin of the graft copolymer is obtained by putting it into a kneader machine substituted with nitrogen gas, for example, a Banbury mixer, a double screw mixer, etc., and melt-kneading it at a temperature of 120 to 300 ° C. for 0.1 to 30 minutes. Can be obtained. At the time of copolymerization, the reaction can be efficiently carried out by adding a conventional radical generator.

The radical generator is not particularly limited, and is, for example, hydroperoxides such as diisopropylbenzene hydroperoxide and 2,5-dimethyl-2,5-di (hydroperoxy) hexane; di-t-butyl peroxide. , 2,5-Dimethyl-2,5-di (t-butylperoxy) hexane and other dialkyl peroxides; organic peroxides such as benzoyl peroxide and other diacyl peroxides, or azobisisobutyronitrile And the like, azo compounds and the like can be mentioned. Only one of these radical generators may be used as a single substance, or two or more of these radical generators may be used in combination. The amount of the radical generator added is preferably in the range of 0.001 to 5 parts by mass with respect to 100 parts by mass of the total amount of the above-mentioned raw material polymerization components.

The content of the residue derived from unsaturated carboxylic acid is 0.05 to 3.0% by mass, more preferably 0.1% by mass or more and 1.0% by mass in the total mass of the acid-modified polyolefin resin composition. Is less than.

If the amount of unsaturated carboxylic acid residue in the adhesive resin layer is larger than the above range, the acid content of the laminate increases, so that the hygroscopicity becomes high and there is a possibility of foaming during extrusion. In addition, there is a high possibility that the residual monomer of the unsaturated carboxylic acid is eluted from the adhesive resin layer, and there is a concern about hygiene. Further, the laminated body tends to be inferior in bending resistance. Furthermore, since the corrosiveness to metal is increased, problems are likely to occur in the manufacturing process. Further, if the amount of unsaturated carboxylic acid residue is less than the above range, the interaction with the multilayer is reduced, which may cause a decrease in the interlayer adhesion strength.

The content of the residue derived from the (meth) acrylic acid ester is preferably 5 to 40% by mass, more preferably 10 to 30% by mass, based on the total mass of the acid-modified polyolefin resin composition.

When the content of the residue derived from the (meth) acrylic acid ester is larger than the above range, the softening point of the acid-modified polyolefin resin composition becomes low, and stickiness tends to occur at room temperature, resulting in poor handling. Further, when the content of the residue derived from the (meth) acrylic acid ester is less than the above range, adhesion due to the reaction of the acrylate is less likely to occur, and the interlayer adhesion strength tends to decrease.

Furthermore, alkene-derived residues, modifying resins, additives and the like may be contained.

The MFR of the acid-modified polyolefin resin composition is preferably 3 to 100 g / 10 minutes at 190 ° C., and more preferably 5 to 20 g / 10 minutes. If the MFR is outside the above range, there is a problem that extrusion becomes difficult.

The thickness of the adhesive resin layer is preferably 0.1 to 200 μm, more preferably 1 to 100 μm, and even more preferably 5 to 25 μm. If it is thinner than this range, sufficient laminating strength cannot be obtained, and the rigidity becomes too high, which may cause delamination at the time of opening or the like. On the contrary, if it is thicker than the above range, the low temperature sealing property is deteriorated and it becomes difficult to process with a production machine. In addition, excessive use of resin leads to an increase in packaging material cost and excessive rigidity as a lid material. As a result of the rigidity becoming too high and the flexibility being impaired, it is not possible to follow the curvature of the base material / sealant, and film breakage and film residue are likely to occur.

The adhesive mechanism of the adhesive resin layer in the present invention includes a mechanism of adhering by the flexibility of the adhesive resin layer, a mechanism of adhering by compatibility with the resin, and a chemical interaction between the surface of the mating substrate and the unsaturated carboxylic acid. There is a mechanism for bonding with, a mechanism for bonding by chemical interaction between unsaturated carboxylic acid and acrylate on the surface of the mating substrate, and a mechanism for bonding by generating radicals by extruding at a high temperature.

The adhesive resin layer is not necessarily bonded by only one bonding mechanism, but at least two or more of the above mechanisms contribute to the bonding. For example, for polyethylene, ethylene copolymer, etc., compatibility mainly due to the alkene portion contributes to adhesion. Further, the bond between the unsaturated carboxylic acid and the polar group of the mating substrate contributes to the vapor-deposited film of the gas barrier film and the gas barrier coating layer. In addition, the chemical interaction between the acrylate and the unsaturated carboxylic acid contributes to the layer made of PP or PET.

<Sealant layer>
In the present invention, the sealant layer is a layer made of a sealant film having a polyethylene-based resin layer and an easy peel layer exposed on the surface, and the easy peel layer adheres to the bottom material of the packaging container during heat sealing, and the packaging container. When peeling from, the lid material is peeled off due to the cohesive failure of the easy peel layer and the peeling of the sea-island interface.

The polyethylene-based resin layer is a support layer for the easy peel layer, and is firmly bonded to the adhesive resin layer described above, and exhibits high interlayer adhesive strength.

Examples of the resin constituting the polyethylene-based resin layer include various polyethylenes such as low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, and high-density polyethylene, which are superior in terms of workability and adhesiveness. Therefore, low density polyethylene (LDPE, density 0.910 or more and less than 0.930) and linear low density polyethylene (LLDPE, density 0.910 to 0.925) are generally preferably used. However, when high-density polyethylene (HDPE, density 0.942 or higher) is used, excellent resistance to film breakage during high-temperature sealing can be exhibited.

Further, in the present invention, the classification of various polyethylenes refers to those defined in the former JIS K6748: 1995 and JIS K6899-1: 2000.

The layer thickness of the polyethylene-based resin layer is 5 to 100 μm, preferably 5 to 70 μm, and more preferably 10 to 60 μm. When the polyethylene-based resin layer is, for example, two layers composed of a high-density polyethylene layer and a low-density polyethylene layer, the thickness of the high-density polyethylene layer is 2.5 to 97.5 μm, preferably 2.5 to 97.5 μm. The thickness of the low-density polyethylene layer is 67.5 μm, more preferably 2.5 to 57.5 μm, and the thickness of the low-density polyethylene layer is 2.5 to 97.5 μm, preferably 2.5 to 67.5 μm, still more preferably 2. It is 5 to 57.5 μm.

On the other hand, the easy peel layer is the innermost layer of the packaging container and is a layer made of a blended polymer containing two or three or more kinds of resins that are incompatible with each other. By providing a layer made of this blend polymer on the polyethylene-based resin layer (support layer) and laminating it with the base material layer via the adhesive resin layer, the sealing strength, the sealing property and the sealing property suitable as a lid material are easy. Peelability (easy peeling property) can be established at the same time, and stable and good sealing property and opening property can be achieved without causing film breakage or film residue.

The blend polymer is a blend of two or three or more kinds of resins that are incompatible with each other, and does not actively react with each other. And since they are incompatible with each other, they form a sea-island structure. Since it is incompatible and the bond between the sea-island interface is weak, peeling is likely to occur at the sea-island interface at the time of peeling, and the easy peeling property of the entire easy peel layer can be brought about.

Any combination of resins that are incompatible with each other can be used as the blend polymer, and suitable combinations include, for example, a combination of a polyethylene-based resin and a polypropylene-based resin, and a polyethylene-based resin and a polystyrene-based resin. , A combination of an acrylic resin and a polyester resin, and the like.

Further, the type of resin to be blended and the blending ratio thereof can be adjusted according to the composition of the resin on the surface of the flange portion of the bottom material.

For example, when the bottom material is made of a polypropylene resin, a blend polymer containing at least a polyethylene resin and a polypropylene resin is suitable. Furthermore, by properly using various polyethylene-based resins such as low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, and high-density polyethylene as the polyethylene-based resin, and by changing the blend ratio, the seal strength can be obtained. It is possible to adjust.

The blend ratio of the polyethylene-based resin and the polypropylene-based resin is, in terms of mass ratio, polyethylene-based resin / polypropylene-based tree resin = 10/90 to 90/10, preferably 10/90 to 60/40, and further. It is preferably 10/90 to 50/50, and most preferably 20/80 to 50/50. By blending the polyethylene-based resin and the polypropylene-based resin in this ratio, it is possible to achieve a sealing strength suitable as a lid material, an easy peeling property, and an interlayer adhesion strength with a support layer.

Further, for example, when the bottom material is a polyethylene-based resin, a blend polymer containing at least a polyethylene-based resin and a polystyrene-based resin is suitable. Here, examples of the polyethylene-based resin include the same polyethylene-based resin as described above. From the balance of seal strength, easy peeling property and interlayer adhesion strength with the support layer, the blend ratio of the two is, in terms of mass ratio, polyethylene resin / polystyrene tree resin = 10/90 to 90/10, preferably 10/90 to 90/10. It is 20/80 to 60/40, more preferably 20/80 to 50/50, and most preferably 30/70 to 50/50.

By blending the polyethylene-based resin and the polystyrene-based resin in this ratio, it is possible to achieve a sealing strength suitable as a lid material, an easy peeling property, and an interlayer adhesion strength with a support layer.

Further, the sealing strength and the thermal sealing property may be adjusted by adding other thermoplastic resins, elastomers and the like as long as the sealing strength and the easy peeling property are not impaired.

The layer thickness of the easy peel layer is 2 to 70 μm, preferably 2 to 30 μm, more preferably 2 to 10 μm, and particularly preferably 2 to 8 μm. If it is thinner than the above range, the sealing strength with the bottom material becomes low, and sufficient hiding property cannot be obtained. On the contrary, if it is thicker than the above range, the sealing strength with the bottom material becomes too high, and there is a concern that the lid material may be torn at the time of opening.

The sealant film is produced by an arbitrary method such as extrusion coating, but particularly preferably, the polyethylene-based resin layer and the easy peel layer can be co-extruded and formed by a T-die method, an inflation method, or the like. ..

The surface of the sealant film on the polyethylene-based resin side may be subjected to corona treatment, frame treatment, ozone treatment, or the like before laminating with the base material layer via the adhesive resin.

<Bottom material>
The bottom material is a portion of the packaging container for storing the contents, and examples of the material include polypropylene-based resin and polyethylene-based resin. In order to improve the storage stability of the contents, the structure is multi-layered, and a barrier layer is provided in the intermediate layer. As the barrier layer, an ethylene-vinyl alcohol copolymer resin or the like is used.

<Packaging container>
In the packaging container formed by heat-sealing with the lid material of the present invention, the thickness variation of the easy peel layer derived from the lid material is small, and the maximum thickness value-minimum thickness value is within 10% of the average thickness. It can exhibit stable adhesive strength, hiding property, peeling strength, and easy opening property.

Details of the raw materials used in Examples and Comparative Examples are as follows.
Silane coupling agent A: SH6040 manufactured by Dow Corning Toray Industries, Inc. Epoxy group-containing alkoxysilane.
^{Adhesive resin composition A: Rotader (R)} 4503, manufactured by Arkema Co., Ltd. Ethylene-methyl acrylate-maleic acid ternary copolymer. Maleic anhydride component amount 0.3% by mass, methyl acrylate component amount 19% by mass. Melting point 80 ° C.
Adhesive B: Rock Paint Co., Ltd., RU-40 / H-4. Two-component curable urethane adhesive EVOH: Nippon Synthetic Chemical Industry Co., Ltd., Soanol D2908. Ethylene vinyl alcohol copolymer. Ethylene copolymerization ratio 29 mol%.
Polyvinyl alcohol: PVA110 manufactured by Kuraray Co., Ltd. Degree of polymerization = 98-99%, degree of polymerization = 1100.
Ethyl silicate 40: A hydrolyzed condensate of ethyl silicate manufactured by Corcote Co., Ltd. Average pentamer.
PET film A: E-5100 manufactured by Toyobo Co., Ltd. Biaxially stretched product. 12 μm thick, single-sided corona treated.
High-density polyethylene A: HZ3300F manufactured by Prime Polymer Co., Ltd.
High-density polyethylene B: HF-313 manufactured by Japan Polyethylene Corporation.
Low density polyethylene A: LC600A manufactured by Japan Polyethylene Corporation.
Low density polyethylene B: Made by Prime Polymer Co., Ltd., 3510F.
Polypropylene A: FL02-C manufactured by Japan Polypropylene Corporation.
Easy peel film: SMX-1010CL manufactured by J-Film Co., Ltd. Polyethylene (45 μm) / Polyethylene + Polystyrene (5 μm)

<Preparation of base film>
Hexamethyldisiloxane (HMDSO), which is an organic silicon compound, is used as a raw material on the corona-treated surface of a biaxially stretched PET film A having a thickness of 12 μm and one side of which has been corona-treated, using a plasma chemical vapor deposition apparatus. A 20 nm silicon oxide vapor deposition film was provided. Next, the vapor-deposited film surface was subjected to plasma treatment.

<Preparation of gas barrier resin composition>
[Preparation of Gas Barrier Resin Composition A]
The following raw materials were mixed and stirred to prepare solution a.
EVOH 0.610 parts by mass Isopropyl alcohol 3.294 parts by mass Ion-exchanged water 2.196 parts by mass

Next, the following raw materials were mixed and stirred to prepare the solution b.
Ethyl silicate 40 11.460 parts by mass Isopropyl alcohol 17.662 parts by mass,
Acetylacetone Aluminum 0.020 parts by mass,
Ion-exchanged water 13.752 parts by mass

Next, the solution c was adjusted with the following compounding ratio.
Polyvinyl alcohol aqueous solution 1.520 parts by mass Silane coupling agent A 0.050 parts by mass Acetic acid 0.130 parts by mass Isopropyl alcohol 13.844 parts by mass Ion-exchanged water 35.462 parts by mass

Solution b was added to the solution a obtained above and stirred, and further, solution c was added and stirred to obtain a colorless and transparent gas barrier resin composition A.

<Preparation of blended polymer>
[Preparation of blend polymer A]
The following raw materials were mixed and melt-kneaded to obtain a blend polymer A.
High-density polyethylene A 30 parts by mass Polypropylene A 70 parts by mass

[Preparation of blend polymer B]
A blend polymer B was prepared by operating in the same manner as the blend polymer A according to the formulation shown in Table 2.

<Example 1>
(1) Preparation of Base Material Layer Film A gas barrier resin composition A is applied to the plasma-treated surface of PET film A and heat-treated at 100 ° C. for 30 seconds to a thickness of 0.4 g / m ² (dry operation state). ) Gas barrier resin composition A was applied and dried to prepare a base material layer film.
(2) Preparation of sealant layer film A two-layer film of high-density polyethylene B (45 μm) / blend polymer A (5 μm) using high-density polyethylene B for the polyethylene-based resin layer and blend polymer A for the easy peel layer. Was formed to prepare a sealant layer film.
(3) Preparation of Laminated Film The base film produced in (1) above is set in an extrusion laminating machine, and the adhesive resin composition A is spread on the gas barrier resin layer surface thereof so as to have a thickness of 20 μm. It was melt-extruded from a die at 330 ° C., and at the same time, the sealant film prepared in (2) above was unwound and laminated by sandwich lamination to obtain a laminated film having the following layer structure.
PET film A (12 μm) / Silicon oxide vapor deposition film (200 nm) / Gas barrier resin composition A (0.4 g / m ² ) / Adhesive resin composition A (20 μm) / High density polyethylene B (45 μm) / Blend polymer A (5 μm)
(4) Preparation of Lid Material The laminated film obtained in (3) is cut into a single-wafer shape and punched into a rectangle with knob pieces at the corners according to the shape of the opening of the bottom material. A lid material was produced.
(5) Preparation of packaging container The surface of the easy peel layer of the lid material obtained above is overlapped so as to face the flange portion at the periphery of the opening of the tray-shaped container bottom material made of polypropylene, and the sealer (tester industry). The packaging container of the present invention was produced by heat-sealing under the conditions of a sealing temperature of 160 ° C., a pressure of 5.0 MPa, and a time of 1 second using TP-701-A) manufactured by the same company.
(6) Evaluation Using the obtained lid material and packaging container, the seal strength, the seal strength storage stability, the easy opening property, and the thickness variation of the easy peel layer were evaluated. The results are shown in Table 3.

[Example 2]
The lid material and packaging container of the present invention were produced and evaluated in the same manner as in Example 1 except that the thickness of the adhesive resin layer was set to 15 μm.

[Example 3]
The lid material and packaging container of the present invention were produced and evaluated in the same manner as in Example 1 except that the thickness of the adhesive resin layer was 10 μm.

[Example 4]
The lid material and the packaging container B of the present invention were manufactured and evaluated in the same manner as in Example 1 except that the thickness of the high-density polyethylene B layer of the sealant layer was set to 60 μm.

[Example 5]
The lid material and packaging container of the present invention were produced and evaluated in the same manner as in Example 1 except that the easy peel layer was a blend polymer B instead of the blend polymer A.

[Example 6]
Implemented except that the polyethylene-based resin layer of the easy peel layer was replaced with low-density polyethylene B (22.5 μm) / high-density polyethylene B (22.5 μm, easy peel layer side) instead of high-density polyethylene B (45 μm). The lid material and packaging container of the present invention were produced and evaluated in the same manner as in Example 1.

[Comparative Example 1]
As a laminating method, the lid material is the same as in Example 1 except that the adhesive resin composition A is melt-extruded and laminated by sandwich laminating, but the adhesive resin composition B is used and laminated by dry laminating. And packaging containers were manufactured and evaluated. The coating amount of the adhesive resin composition B was 3 g / m ² (dry film thickness).

[Comparative Example 2]
A urethane-based anchor coating agent (manufactured by Mitsui Chemicals Co., Ltd., A-3210 / A-3075) 0.3 g / m ² (dry film thickness) is applied to the surface of the gas barrier coating film of the base material layer film and adhered. A lid material and a packaging container were produced and evaluated in the same manner as in Example 1 except that low-density polyethylene A was melt-extruded and laminated in place of the sex resin composition A.

[Comparative Example 3]
The lid material and packaging container of the present invention are the same as in Example 1 except that the sealant layer film is an easy peel film (50 μm) instead of the high-density polyethylene B (45 μm) / blend polymer A (5 μm). Was manufactured and evaluated.

<Details of evaluation items>
The details of the evaluation items carried out are as follows.

[Seal strength]
The lid material obtained in each Example and Comparative Example and the polypropylene film of the same quality as that used for the tray-shaped container bottom material are heat-sealed under the following sealing conditions and cut into strips having a width of 15 mm. Then, a test piece was prepared, and the seal strength (N / 15 mm width) at 110 ° C. to 180 ° C. was measured using a tensile tester.

[Seal strength storage stability]
Further, the test piece sealed at 160 ° C. is housed together with the solid curry roux in a sealed container, and the sealing strength after being left at 40 ° C. × 75% RH for 30 days is similarly measured to improve the storage stability of the sealing strength. evaluated. The results are shown in Table 3.
Storage rate (%) = average seal strength after leaving / average seal strength immediately after sealing x 100
Heat seal condition Sealer: TP-701-A manufactured by Tester Sangyo Co., Ltd.
Temperature: 150-180 ° C
Pressure: 5.0 MPa
Time: 1 second Tensile strength test conditions Test speed: 300 mm / min Peeling angle: 180 °
Pass / Fail Criteria: Must be within the range of 7 to 12 N / 15 mm.

[Easy to open]
Ten samples were prepared for each of the packages obtained in each Example and Comparative Example. This sample was opened immediately, and the presence or absence of film tearing / breaking of the lid material (number of samples in which film tearing / breaking occurred / 10 pieces) was counted. The results are shown in Table 3.

[Easy peel layer thickness variation]
For each container of the packaging container obtained in each Example and Comparative Example, the thickness of the easy peel layer after heat sealing was measured at 15 points, the average value, the maximum value, and the minimum value were calculated, and the thickness variation was measured. evaluated. The results are shown in Table 3.

<Summary of results>
Examples 1 to 6 showed good results, while Comparative Examples 1 to 3 showed insufficient sealing strength or opening property at a normal sealing temperature of 150 to 170 ° C., and further, 40 ° C. × 75%. RH, the seal strength after being left for 30 days had deteriorated to an insufficient level. In addition, there was a large variation in the thickness of the easy peel layer after heat sealing.

The lid material of the present invention is an environmentally friendly lid material due to weight reduction and simplification of the manufacturing process, but has the easy peeling property, gas barrier property, and fragrance retention property required as a lid material, and is a film at the time of opening. Since it has the ability to prevent residue, film tearing, and breakage, it can be suitably used for a lid material for containing a large amount of spices or contents containing a large amount of spices such as curry roux, and a packaging container using the lid material.

1: Base material layer 2: Adhesive resin layer 3: Sealant layer 3a: Polyethylene resin layer 3b: Easy peel layer 4: Lid material 5: Bottom material

Claims (15)

A film-like lid material having at least a base material layer, a sealant layer, and an adhesive resin layer for adhering the base material layer and the sealant layer.
The base material layer has a gas barrier layer and has a gas barrier layer.
The adhesive resin layer is a melt-extruded layer formed by using an acid-modified polyolefin resin composition.
The sealant layer has a polyethylene-based resin layer and an easy peel layer exposed on the surface.
The polyethylene-based resin layer has a multi-layer structure having a low-density polyethylene layer and a high-density polyethylene layer, and the high-density polyethylene layer exists between the low-density polyethylene layer and the easy peel layer. And
The easy peel layer is a lid material made of a blend polymer containing two or more kinds of resins that are incompatible with each other. The spice-resistant lid material according to claim 1, for a spice or a packaging container for containing a large amount of spice-containing contents. The lid material according to claim 1 or 2, wherein the gas barrier layer has a silicon oxide vapor deposition layer or an aluminum oxide vapor deposition layer deposited on a plastic film. The gas barrier layer further has a gas barrier resin coating layer.
The gas barrier resin coating layer has a thickness of 0.01 to 100 μm and contains one or more alkoxides represented by the following general formula (1) and a water-soluble polymer having a hydroxyl group. A coating film layer formed by producing a hydrolyzed polycondensate by a sol-gel method of a gas barrier resin composition.
The lid material according to any one of claims 1 to 3.
R ¹ _n M (OR ² ) _m (1)
(In the formula, M represents a metal atom, R1 and R2 represent an organic group having 1 to 8 carbon atoms, n is an integer of 0 or more, m is an integer of 1 or more, and n + m is the valence of M. Represents) The adhesive resin layer is
It has a thickness of 5 to 25 μm and has a thickness of 5 to 25 μm.
The solvent content in the adhesive resin layer is 0% by mass or 1% by mass or less.
The lid material according to any one of claims 1 to 4, wherein the acid-modified polyolefin resin composition has an MFR value of 3 to 100 g / 10 minutes at 190 ° C. The thickness of the polyethylene-based resin layer is 5 to 70 μm, and the thickness is 5 to 70 μm.
The thickness of the easy peel layer is 1 to 20 μm.
The lid material according to any one of claims 1 to 5. The thickness of the low-density polyethylene layer is 2.5 to 35 μm.
The thickness of the high-density polyethylene layer is 2.5 to 35 μm.
The lid material according to any one of claims 1 to 6. The lid material according to any one of claims 1 to 7 , wherein the acid-modified polyolefin resin is at least a copolymer of an alkene, a (meth) acrylic acid ester, and an unsaturated carboxylic acid. The eighth aspect of the present invention, wherein the content of the residue derived from the unsaturated carboxylic acid in the copolymer is 0.05% by mass or more and less than 1.0% by mass in the total amount of the copolymer. Lid material. The lid material according to claim 8 or 9 , wherein the content of the residue derived from the (meth) acrylic acid ester in the copolymer is 5 to 40% by mass in the total amount of the copolymer. The lid material according to any one of claims 1 to 10 , wherein the blend polymer contains at least a polyethylene resin and a polypropylene resin and has a sea-island structure. The lid material according to claim 11 , wherein the mass ratio of the polyethylene-based resin to the polypropylene-based resin of the blend polymer is polyethylene-based resin / polypropylene-based resin = 10/90 to 50/50. The lid material according to any one of claims 1 to 10 , wherein the blend polymer contains at least a polyethylene resin and a polystyrene resin and has a sea-island structure. The lid material according to claim 13 , wherein the mass ratio of the polyethylene-based resin to the polystyrene-based resin of the blend polymer is polyethylene-based resin / polystyrene-based resin = 20/80 to 50/50. A packaging container formed of the lid material according to any one of claims 1 to 14 and a bottom material made of polypropylene-based resin or polyethylene-based resin.
A packaging container in which the sealant layer of the lid material and the peripheral flange portion of the opening of the bottom material are heat-sealed.

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