JP2013177194A - Lid material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lid material indicating superior punching suitability and shock resistance, and reducing a load to the environment since a high biomass degree of at least 18% is indicated as a lid material as a whole.SOLUTION: A lid material comprises a laminated film having at least a base material layer and a sealant layer. The sealant layer is a layer comprising a sealant film formed by co-extruding and laminating at least a polyethylene resin layer and an easy peel layer. The easy peel layer comprises a polymer blend including at least two types of resins. The polyethylene resin layer is positioned between the base material layer and the easy peel layer, and the layer comprises a polyethylene resin composition comprising (a) straight chain low-density polyethylene derived from plants, (b) low-density polyethylene derived from non-plants, (c) straight chain low-density polyethylene derived from non-plants, and (d) an additive in which a total of (a)-(d) is 100 mass%, and a mixed amount of the polyethylene resin composition with respect to the whole of the sealant film is 50 mass% or more.

Description

  The present invention relates to a lid made of a laminated film having a plant-derived sealant film, and more particularly to a lid that exhibits excellent punchability and impact resistance and exhibits a high degree of biomass.

In recent years, in order to reduce the burden on the environment, it has been studied to replace a part of the raw material of the resin film with a plant-derived resin from a petroleum-derived resin (Patent Document 1). Plant-derived resins are expected to have the same physical properties as conventional petroleum-derived resins, with no change in chemical structure.
However, actually, a resin film containing a plant-derived resin exhibits different properties from a resin film made only of a petroleum-derived resin.
For example, in a sealant film made of a polyethylene resin, when a part of the raw material is changed to a plant-derived polyolefin resin, as the blending ratio increases, the punching ability of the film deteriorates and the impact resistance decreases. I found out that
Therefore, a sealant film exhibiting such a high degree of biomass is unsuitable for use as a cover material, and it is difficult to punch the cover material with a beautiful cut surface when attempting to produce a cover material using this sealant film. Met. In addition, there is a problem that it is easily broken and is vulnerable to impacts such as dropping.

JP 2009-155516 A

  The present invention solves the above-mentioned problems, exhibits excellent punchability and impact resistance, and exhibits a high degree of biomass of at least 18% as a whole of the cover material. Therefore, the cover material has a reduced environmental load. The purpose is to provide.

As a result of various studies, the inventor of the present invention has a cover material composed of a laminated film having at least a base material layer and a sealant layer, and the sealant layer is a sealant obtained by coextruding at least a polyethylene resin layer and an easy peel layer. A layer made of a film, the easy peel layer is a layer made of a polymer blend containing at least two kinds of resins, the polyethylene resin layer is located between the base material layer and the easy peel layer, and The following components: (a) Plant-derived linear low density polyethylene (LLDPE) 20 to 70% by mass, (b) Density 0.920 to 0.933 kg / m ³ and MFR 0.5 to 3.5 g / 10 15% to 65% by mass of non-plant-derived low-density polyethylene (LDPE) having physical properties, (c) obtained by copolymerization of ethylene and an α-olefin having 6 carbon atoms And a density 0.914~0.937kg / m with a ³ and MFR0.9~3.0g / 10 min physical properties, non-plant-derived linear low density polyethylene (LLDPE) 15 to 65 wt%, and (D) A layer made of a polyethylene resin composition comprising 0 to 20% by mass of an arbitrary additive, wherein the total of (a) to (d) is 100% by mass, and is based on the entire sealant film. The amount of the polyethylene-based resin composition is 50% by mass or more, and it has been found that the lid material achieves the above object.

The present invention is characterized by the following points.
1. A cover material comprising a laminated film having at least a base material layer and a sealant layer, wherein the sealant layer is a layer comprising a sealant film obtained by coextrusion laminating a polyethylene resin layer and an easy peel layer, and the easy peel The layer is a layer made of a polymer blend containing at least two kinds of resins, and the polyethylene-based resin layer is located between the base material layer and the easy peel layer, and includes the following components: (a) plant-derived (B) Non-plant-derived LDPE having physical properties of 20 to 70% by mass, (b) density 0.920 to 0.933 kg / m ³ and MFR 0.5 to 3.5 g / 10 min, (c) obtained in the copolymerization of ethylene and C 6 of the α- olefin, and a density 0.914~0.937kg / m ³ and MFR0.9~3.0g / 10 min ones Non-plant-derived LDPE having 15 to 65% by mass, and (d) an optional additive 0 to 20% by mass, a layer made of a polyethylene resin composition, wherein (a) to (d) The above-mentioned lid material is characterized in that the total amount is 100% by mass, and the blending amount of the polyethylene-based resin composition with respect to the entire sealant film is 50% by mass or more.
2. The said sealant layer is a layer which consists of a sealant film which co-extruded the said polyethylene-type resin layer, the said easy peel layer, and the heat seal layer used as an innermost layer in this order, The said 1 characterized by the above-mentioned. Cover material.
3. The said base material layer is a layer which consists of a polyethylene terephthalate (PET) film whose biomass degree which consists of plant-derived raw materials is 15-100%, The lid | cover material of said 1 or 2 characterized by the above-mentioned.
4). The lid material according to any one of the above 1 to 3, wherein the biomass degree of the entire lid material is at least 18%.

The laminated film constituting the lid material of the present invention contains a plant-derived resin at a high blending ratio, that is, exhibits a high degree of biomass. Therefore, from the viewpoint of carbon neutral, the increase in the amount of CO _{2 in} the atmosphere is suppressed, and the use of petroleum resources is also saved.
Carbon neutral means that even if a plant is burned, the amount of CO ₂ emitted at that time is equal to the amount of CO ₂ absorbed by the plant during growth, so it affects the increase or decrease in the amount of CO _{2 in} the atmosphere. It means not. Therefore, an increase in the amount of CO ₂ can be suppressed as the amount of plant-derived materials increases.

The sealant film constituting the lid material of the present invention comprises a resin composition (hereinafter referred to as “resin composition of the present invention”) containing the above-mentioned components (a) to (d) in a specific ratio. It has a polyethylene resin layer. As a result, even when this sealant film contains a plant-derived polyolefin resin at a high blending ratio, the punchability and impact resistance are not lowered.
Further, the sealant film constituting the lid material of the present invention is obtained by coextrusion laminating a polyethylene resin layer made of the resin composition of the present invention, an easy peel layer made of a polymer blend, and optionally a heat seal layer. It is the film of the multilayer structure which becomes.
In this sealant film, by providing a thick polyethylene-based resin layer made of the resin composition of the present invention, this layer functions as a cushion layer when heat-sealing the adherend surface of the container. Thereby, the lid | cover material of this invention which consists of a laminated | multilayer film which has this sealant film can follow the unevenness | corrugation of a to-be-adhered surface, and can show high sealing performance.
In particular, by providing the polyethylene resin layer thickly so that the blending amount of the resin composition of the present invention is 50% by mass or more based on the entire sealant film, the sealing performance as a lid material is increased, and A high degree of biomass is achieved. Moreover, in this invention, even if it makes a polyethylene-type resin layer thick in this way, the punching suitability and impact resistance of a cover material are not impaired.

It is a schematic sectional drawing which shows the example about the layer structure of the laminated | multilayer film which comprises the cover material of this invention. It is a schematic sectional drawing which shows another example about the layer structure of the laminated | multilayer film which comprises the cover material of this invention.

The above-described present invention will be described in more detail below.
Hereinafter, the resin names used in the present invention are those commonly used in the industry.
In the present invention, the density is a value measured according to JIS-K7112. The MFR is a value measured according to JIS K 7210.

<I> Layer structure of laminated film constituting cover material of the present invention FIG. 1 is a schematic cross-sectional view showing an example of the layer structure of the laminated film constituting the cover material of the present invention.
As shown in FIG. 1, the laminated film constituting the lid material of the present invention comprises a base material layer 1 and a sealant layer 2, and the sealant layer 2 comprises a polyethylene resin comprising the resin composition of the present invention. It consists of the sealant film which co-extruded the layer 3 and the easy peel layer 4 which consists of polymer blends. Here, the polyethylene resin layer 3 is located between the base material layer 1 and the easy peel layer 4. Moreover, the polyethylene-type resin layer 3 is provided by the thickness from which the compounding quantity of the polyethylene-type resin composition with respect to the sealant layer 2 whole becomes 50 mass% or more.

FIG. 2 is a schematic cross-sectional view showing another example of the layer structure of the laminated film constituting the lid material of the present invention.
As shown in FIG. 2, in the laminated film constituting the lid material of the present invention, the sealant layer 2 is a sealant film obtained by coextrusion laminating the polyethylene resin layer 3, the easy peel layer 4 and the heat seal layer 5 in this order. Consists of. Here, the heat seal layer 5 forms an outermost layer (a layer that becomes an innermost layer when used as a lid member).

<II> Base material layer In the present invention, as the base material layer, an arbitrary base material that retains strength necessary for a lid, heat resistance at the time of sealing, dead hold property, flatness, etc., depending on the packaging application. Can be used. Examples of the substrate suitably used in the present invention include various papers such as imitation paper, clay coated paper, kraft paper, paperboard, synthetic paper, polyester resin film, polyamide resin film, polyolefin resin film, and the like. These various resin films, vapor-deposited films having a vapor-deposited layer such as metal oxide, metal films such as aluminum foil, other various barrier films, light-shielding films, and multilayer laminated films obtained by laminating these films. Lamination of the film can be performed by any method.

In the present invention, a plant-derived PET film or a polylactic acid (PLA) film made of PET made from plant-derived ethylene glycol or isobutanol can also be used.
By using a plant-derived PET film or PLA film, for example, a PET film or PLA film showing a biomass degree of 15 to 100% as a base film, the laminated film of the present invention can achieve a higher biomass degree as a whole. it can.
A plant-derived PET film can be produced by substituting a part or all of monoethylene glycol (MEG) and terephthalic acid (PTA) as raw materials with a plant-derived one.
Plant-derived MEG is produced by fermenting sugar solution and starch obtained from plants such as sugarcane with microorganisms such as yeast to produce bioethanol according to a conventional method, and heating it in the presence of a catalyst. Ethylene is obtained by a dehydration reaction and can be derived therefrom.

Plant-derived PTA can be derived from paraxylene which is produced from isobutanol produced from sugar solution or starch by microorganisms.
Presence of a conventional catalyst with about 15-30% by weight of plant-derived or non-plant-derived MEG, 55-85% by weight of plant-derived or non-plant-derived PTA and optionally 0-15% by weight of optional components and comonomers Under polycondensation reaction. By forming the obtained PET into a film and further stretching it in a biaxial direction in order to enhance dimensional stability and heat resistance, if desired, a PET film suitably used in the present invention can be produced. it can.
In addition, in this invention, "plant origin" means containing the carbon derived from the plant raw material manufactured from the alcohol obtained by using a plant as a raw material.
The base film may have any thickness depending on the application.

<III> Sealant layer
Polyethylene resin layer In the present invention, the polyethylene resin layer in the sealant layer comprises (a) plant-derived LLDPE of 20 to 70% by mass, (b) density of 0.920 to 0.933 kg / m ³ and MFR 0.5 to ³ . Non-plant-derived LDPE having a physical property of 0.5 g / 10 min, 15 to 65% by mass, (c) obtained by copolymerization of ethylene and an α-olefin having 6 carbon atoms, and having a density of 0.914 to 0. Non-plant derived LLDPE having physical properties of 937 kg / m ³ and MFR 0.9 to 3.0 g / 10 min, and (d) polyethylene of the present invention consisting of optional additives 0 to 20% by mass It consists of a resin composition.
By providing the thickness of the polyethylene resin layer so that the blending amount of the polyethylene resin composition with respect to the entire sealant film is 50% by mass or more, the sealing performance as a cover material is increased and a high degree of biomass is achieved. Is done.

Plant-derived LLDPE
Component (a) plant-derived LLDPE depends on the physical properties of other components (b) petroleum-derived LDPE and component (c) petroleum-derived LLDPE in the resin composition, and the use of the film after film formation. And having an arbitrary density and MFR within the definition defined by JIS K6899-1: 2000.
In the resin composition of this invention, component (a) plant-derived LLDPE is mix | blended in 20-70 mass%, Preferably it is 20-60 mass%.
Since the resin composition of the present invention contains 20% by mass or more of plant-derived LLDPE, a high degree of biomass can be achieved. However, if this amount exceeds 70% by mass, it is not possible to prevent the deterioration of punching suitability and impact resistance as a sealant film that occurs when the plant-derived resin is blended.

  As a method for producing plant-derived LLDPE, bioethanol is produced by fermenting a sugar solution or starch obtained from a plant such as sugarcane, corn, or sweet potato with a microorganism such as yeast according to a conventional method. Heating in the presence, ethylene and α-olefin (1-butene, 1-hexene, etc.) are obtained by intramolecular dehydration reaction or the like. Then, using these as monomers, a plant-derived LLDPE can be produced by copolymerization in the presence of a conventional catalyst in the same manner as in the production of petroleum-derived LLDPE. As the comonomer α-olefin generally used in the production of LLDPE, in addition to the plant-derived α-olefin, a petroleum-derived one can also be used.

Examples of the polymerization method include polymerization methods such as a low pressure method, a slurry method, a solution method, and a gas phase polymerization method.
In addition, as a catalyst at the time of polymerization, a single site catalyst such as a metallocene catalyst or a multisite catalyst such as a Ziegler-Natta catalyst can be mentioned. From the viewpoint of excellent structural uniformity, the use of a single site catalyst such as a metallocene catalyst can be used. preferable.
The method for producing plant-derived LLDPE is described in detail in, for example, JP-T-2011-506628.
Examples of plant-derived LLDPE preferably used in the present invention include Green PE manufactured by Braskem SA.

Non-plant-derived (petroleum-derived) LDPE
In the present invention, “non-plant-derived” or “petroleum-derived” LDPE does not include a plant-derived polyethylene resin and, as usual, uses ethylene obtained by pyrolyzing naphtha obtained from petroleum as a raw material. Means LDPE produced by polymerizing by a high pressure method.
According to a conventional method, the density of the obtained resin can be controlled to a desired value by selecting a catalyst and adjusting the monomer concentration during polymerization. In addition, the MFR of the obtained resin can be controlled to a desired value by selecting a catalyst, adjusting the hydrogen concentration during polymerization, and the like.
The petroleum-derived LDPE used in the present invention has a density of 0.920 to 0.933 kg / m ³ , more preferably 0.920 to 0.925 / m ³ , MFR 0.5 to 3.5 g / 10 min, Preferably, it has a physical property of 0.8 to 3.0 g / 10 min.

Decreasing punchability caused by blending of plant-derived resin by blending petroleum-derived LDPE having such specific physical properties into the resin composition by 15 to 65 mass%, more preferably 15 to 50 mass% Can be prevented.
If the blending amount of petroleum-derived LDPE is less than 15% by mass, the film is stretched when punched into the shape of the lid, and the punching suitability is poor. On the other hand, when it is more than 65% by mass, the film is inferior in waist and strength.
Moreover, said effect is not acquired as the density of LDPE derived from petroleum is out of the said range.
Examples of petroleum-derived LDPE suitably used in the present invention include UBE polyethylene ^(R) manufactured by Ube Maruzen Polyethylene Co., Ltd.

Non-plant derived (petroleum derived) LLDPE
In the present invention, “non-plant-derived” or “petroleum-derived” LLDPE does not include a plant-derived polyethylene resin, and conventionally uses ethylene obtained by pyrolyzing naphtha obtained from petroleum as a raw material. Is an LLDPE produced by copolymerizing with a comonomer species α-olefin in the presence of a conventional catalyst.
The α-olefin is preferably an α-olefin having 6 carbon atoms, such as 1-hexene, 2-ethyl-1-butene, 2,3-dimethyl-1-butene, 2-methyl-1-pentene, 3- And methyl-1-pentene, 4-methyl-1-pentene, and 3,3-dimethyl-1-butene. By using these α-olefins having 6 carbon atoms, the mechanical strength of the film after film formation is improved, and a reduction in impact resistance caused by the blending of the plant-derived resin can be effectively prevented.
Examples of the copolymerization method include polymerization methods such as a low pressure method, a slurry method, a solution method, and a gas phase polymerization method.

In addition, examples of the catalyst at the time of copolymerization include a single site catalyst such as a metallocene catalyst or a multisite catalyst such as a Ziegler-Natta catalyst, but it has excellent impact resistance, has few soluble components, and is excellent in blocking resistance. Since a resin composition is obtained, it is preferable to use a single site catalyst such as a metallocene catalyst.
According to a conventional method, the density of the resin obtained can be controlled to a desired value by selecting a catalyst or adjusting the comonomer concentration at the time of copolymerization. In addition, the MFR of the obtained resin can be controlled to a desired value by selecting a catalyst or adjusting the hydrogen concentration during copolymerization.
The petroleum-derived LLDPE used in the present invention has a density of 0.914 to 0.937 kg / m ³ , more preferably 0.916 to 0.930 kg / m ³ , MFR 0.9 to 3.0 g / 10 min, and more. Preferably, it has a physical property of 0.9 to 2.7 g / 10 min.

By forming 15 to 65 mass%, more preferably 15 to 60 mass% of petroleum-derived LLDPE having such specific physical properties into the resin composition, film formation is caused by the blending of plant-derived resin. It is possible to prevent the impact resistance of the subsequent film from being lowered.
If the blending amount of petroleum-derived LLDPE is less than 15% by mass, the film after film formation is inferior in impact resistance and cannot be applied to a sealant for a lid. On the other hand, when it is more than 65% by mass, the punching ability is lowered.
If the density and MFR of petroleum-derived LLDPE are out of the above ranges, the effect of preventing the impact resistance from being lowered cannot be obtained.
Examples of petroleum-derived LLDPE preferably used in the present invention include Evolue ^(R) manufactured by Mitsui Chemicals.

Additives The resin composition of the present invention may contain any additive in a range that does not significantly impair the effects of the present invention, for example, in the range of 0 to 20% by mass.
Additives added to the resin composition of the present invention include various resin additives commonly used to adjust various molding properties and productivity of resin films, such as anti-blocking agents, Examples include slip agents (lubricants), antioxidants, pigments, flow control materials, flame retardants, fillers, ultraviolet absorbers, and surfactants.

Easy peel layer In the laminated film forming the lid of the present invention, the sealant film forming the sealant layer may be one obtained by co-extrusion laminating two layers of a polyethylene resin layer and an easy peel layer. In the laminated film, the easy peel layer forms the outermost surface in contact with the adherend surface of the container, i.e., the innermost layer of the package, and is melted by heat sealing to form the adherend surface of the container. It is a layer to be bonded.
In the present invention, the easy peel layer in the sealant layer is a layer made of a polymer blend containing at least two kinds of resins.
In the present invention, the polymer blend is mainly composed of two types of thermoplastic resins that are incompatible or partially compatible with each other. Of these resins, the one with a higher component ratio becomes the sea, and the one with a lower component ratio takes a so-called “sea-island structure” in which an island is formed. Here, domains made of resin forming islands are dispersed in the sea, that is, the resin phase forming the base. The domain is generally spherical or flat, and by selecting the dispersion state (domain size, shape, amount, etc.) and the type of resin used, the seal strength and easy peel properties as a sealant film are selected. Can be adjusted.
By adopting such a configuration, workability of heat sealing is improved, and stable heat sealing properties and easy peel properties can be obtained.
As a combination of resins forming the easy peel layer of the present invention, any combination of mutually incompatible or partially compatible resins can be used depending on the use of the lid material or the like.

For example, a polyethylene resin, a polypropylene resin, a polystyrene resin, or the like can be used as the base resin that forms the sea. Here, the polyethylene-based resin is relatively versatile in terms of heat-sealability with respect to containers made of various materials, is excellent in low-temperature sealability, has a wide range of seal conditions such as seal temperature, and also adjusts the seal strength. It is easy to perform and is preferable in that it can be suitably used not only for plastic molded containers but also for paper cup containers with polyethylene laminated on the inner surface. In order to obtain a good easy peel property when used for the lid of a paper cup container using such polyethylene laminated paper, it is necessary to adjust the seal strength to about 200 to 500 g / 15 mm width. Adjustment is also possible.
Examples of the polyethylene resin suitably used as the base resin include LDPE, ethylene-vinyl acetate copolymer, and a copolymer of ethylene and acrylic acid or methacrylic acid or an ester thereof. Examples of the incompatible or partially compatible resin to be kneaded with the base resin include styrene polymers, styrene elastomers, polybutene-1, and other tackifiers.

In a preferred embodiment of the present invention, the easy peel layer is a layer made of a polymer blend obtained by kneading polypropylene forming the sea and polyethylene forming the islands.
In another aspect of the present invention, the easy peel layer is a layer made of a polymer blend obtained by kneading a high-density polyethylene (HDPE) that forms the sea and a polybutene-based resin and / or a polystyrene-based resin that forms an island.
In yet another embodiment, the easy peel layer is a layer made of a polymer blend obtained by kneading LLDPE forming the sea and polybutene-based resin and / or polystyrene-based resin forming the island.

In the present invention, examples of the polybutene-based resin include a homopolymer of butene-1 and a copolymer of butene-1 and an α-olefin. Examples of the α-olefin copolymerized with butene-1 include, but are not limited to, ethylene, propylene, pentene-1, hexene-1, and combinations thereof.
Examples of polystyrene resins include homopolymers of styrene monomers such as styrene, alkyl group-substituted or halogen-substituted styrene, and copolymers of the styrene monomer with other monomers. For example, but not limited to.
By comprising these resins, it is possible to provide a sealant film that does not require high material costs, has a degree of freedom in film forming conditions, and has a stable seal.

  In the present invention, in the easy peel layer, the blending ratio of polypropylene, HDPE or LLDPE that forms the sea and polyethylene, polybutene-based resin, or polystyrene-based resin that forms the island is not particularly limited. The ratio is 30 parts by mass of the resin that forms an island with respect to 70 parts by mass of the base resin that forms the sea. In order to obtain cohesive failure, the MFR of polypropylene, HDPE, or LLDPE that forms the sea and the MFR of polyethylene, polybutene-based resin, or polystyrene-based resin that form islands must be 5 or more apart.

Easy peel layers based on polypropylene promote peeling by simple cohesive failure. In addition, an easy peel layer based on HDPE or LLDPE has a delamination factor added together with cohesive failure.
The polymer blend that forms the easy peel layer contains two types of resins that form the sea and islands, and, if necessary, during film formation, for example, film processability, heat resistance, weather resistance, mechanical For the purpose of improving and modifying properties, dimensional stability, antioxidant properties, slipperiness, releasability, flame retardancy, anti-glare properties, electrical properties, strength, etc., various plastic compounding agents and additives, etc. One or more kinds may be optionally added, and if necessary, a solvent, a diluent and the like may be added.
The thickness of the easy peel layer is 2 to 20 μm, preferably 5 to 10 μm. If it exceeds 20 μm, it is not preferred because stringing may occur or the peeled appearance may be impaired. On the other hand, if it is thinner than 2 μm, it cannot be stably formed.

Heat seal layer On the above easy peel layer, a heat seal layer is further laminated, and a laminated film obtained by co-extrusion laminating a polyethylene resin layer, an easy peel layer and a heat seal layer in this order is used as a sealant film. You can also.
In this case, the heat seal layer forms the outermost surface in contact with the adherend surface of the container, that is, the innermost layer surface of the package, and is melted by heat sealing to adhere to the adherend surface of the container. Is a layer.
In the present invention, by further laminating a heat seal layer on the easy peel layer, a lid material showing a higher and more stable seal strength with respect to a polypropylene container can be obtained.

In the present invention, the heat seal layer is made of polypropylene, desirably low melting point polypropylene. As the low melting point polypropylene, a metallocene random polypropylene having a melting point of 105 to 155 ° C., a random copolymer of propylene and other olefins such as ethylene and butene, and a block copolymer can be used. As a polypropylene random copolymer using a metallocene catalyst, “Wintech WFX4TA” manufactured by Nippon Polypro Co., Ltd., “Novatech FW4BT” manufactured by Nippon Polypro Co., Ltd., and the like can be used. The thickness of the heat seal layer is 0.5 to 10 μm, preferably 1 to 5 μm. If it exceeds 10 μm, the heat seal layer is not cut well and the easy peel property is impaired. On the other hand, if it is thinner than 0.5 μm, the effect of increasing the sealing strength and stability cannot be obtained. Further, the heat seal layer may be composed of a polyolefin resin instead of the low melting point polypropylene.
If necessary, the resin forming the heat seal layer can be used, for example, at the time of film formation, such as film processability, heat resistance, weather resistance, mechanical properties, dimensional stability, antioxidant properties, slipperiness, release properties, and the like. For the purpose of improving and modifying the formability, flame retardancy, weather resistance, electrical properties, strength, etc., one or more kinds of various plastic compounding agents and additives are arbitrarily added. If necessary, a solvent, a diluent or the like may be added.

<IV> Production of Laminated Film Constructing Lid Material The laminated film constituting the lid material of the present invention is obtained by laminating the base material layer and the sealant layer.
In this invention, the base film which comprises a base material layer may be arbitrary thickness according to a use.
On the other hand, the sealant film constituting the sealant layer may also have an arbitrary thickness, but is preferably 20 to 100 μm, more preferably 30 to 50 μm, in order to obtain sufficient sealing performance and sealing strength as a cover material. Manufactured with a thickness of
In one embodiment of the present invention, the sealant layer is composed of the polyethylene-based resin layer, the easy peel layer, and optionally a heat seal layer. The resin and the resin composition that are the materials of these layers are transferred to a T-die co-extruder or A sealant film is formed by coextrusion using an extrusion inflation film forming machine or the like.

As a method of laminating the base material layer and the sealant layer, generally, the resin composition of the present invention constituting the polyethylene resin layer of the sealant layer and the polymer constituting the easy peel layer on the laminated surface of the base film. In addition to the method of extruding and laminating blends, extruding by laminating a pre-formed sealant film and substrate film with a roll while extruding an adhesive resin such as polyolefin resin on the lamination surface There are a laminating method (a so-called sandwich laminating method), and a dry laminating method in which a sealant film and a base film, which are formed in advance through an adhesive such as a two-component curing type, are bonded together.
The dry laminating method does not expose the resin to melting at the time of lamination, and reduces the tension applied to the sealant film by making the adhesive application surface the laminated surface on the base film side. Therefore, it is preferable in that a cover material without curling can be produced without causing large shrinkage after bonding.
Examples of the adhesive suitably used for such dry lamination include, but are not limited to, a known polyurethane adhesive composed of a polyol component and a polyisocyanate component. The coating amount of the adhesive is preferably about 0.1 to 10 g / m ² (dry state).

In order to increase the interlayer adhesion between the base material layer and the sealant layer, the base film or the adhesive surface of the sealant film may be subjected to surface treatment in advance. Further, an adhesion assistant layer such as an anchor coat agent or a primer agent may be provided therebetween.
As an anchor coat agent and a primer agent, arbitrary things can be used according to a use. The thickness of the adhesion assistant layer is preferably about 0.1 to 5 g / m ² (dry state).
In a further embodiment of the present invention, a barrier layer may be provided between the base film and the sealant film.

As the barrier layer, a resin film excellent in strength, toughness, heat resistance, moisture resistance, pinhole resistance, puncture resistance, transparency, etc., for example, polyester resin, polyamide resin, polyaramid resin, polyethylene resin , Polypropylene-based resin, polycarbonate-based resin, polyacetal-based resin, fluorine-based resin film, etc., films with excellent light shielding properties, gas barrier properties, etc., for example, metal foil, vapor deposition by depositing inorganic oxide on the vapor deposition substrate Films, polyolefin resin films, polyvinyl alcohol having gas barrier properties, saponified ethylene-vinyl acetate copolymers, nylon MXD6 resin films, and the like can be used.
In particular, when a vapor deposition film is used as the barrier layer, the biomass degree can be further increased by using a plant-derived PET film as the vapor deposition substrate.

  In addition, as a barrier layer, a resin film having an aroma retaining property, for example, polyacrylic resin, polymethacrylic resin, polyacrylonitrile resin, polymethacrylonitrile resin, polystyrene resin, polycarbonate resin, polyethylene terephthalate resin or its Resin obtained by copolymerizing or modifying part of ethylene component and / or terephthalate component with polyhydric alcohol component or dicarboxylic acid component, polyester resin such as polyethylene naphthalate resin, polyamide resin, ethylene-vinyl acetate copolymer saponification Products, polyvinyl alcohol resins, polyvinyl chloride resins, polyvinylidene chloride resins and other resin films can also be used.

The base material layer and the barrier layer, and the barrier layer and the sealant layer can be laminated by a dry laminating method, an extrusion laminating method, an extrusion coating method or the like, similarly to the laminating of the above base material layer and the sealant layer. .
In either case, the adhesion strength between layers can be increased by applying an adhesion aid such as an anchor coat agent or a primer agent to the laminated surface in advance or by performing a pretreatment such as a corona treatment.
In the further aspect of this invention, you may provide printing layers, such as a character, a figure, a symbol, and a design, in the arbitrary positions on a base film or between a sealant film and a base film.

In the present invention, the biomass degree can be further increased by using various adhesives and printing inks containing a plant-derived resin.
In a further embodiment of the present invention, paper is used as the base film, and a printing layer is provided on the paper. In this production process, a water retaining agent is applied to the outer surface of the paper, dried and supplied, and ink such as letters and patterns and overprint varnish are printed thereon and dried. At that time, the outer surface side shrinks and temporarily forms a concave curl on the outer surface side.Then, the inner surface side is printed with a light-shielding ink or the like as necessary, and further, the adhesive is applied thereon as described above. By laminating a sealant layer or a barrier layer via the inner wall, a slight shrinkage is generated on the inner surface side, so that the force of curling concavely on the inner surface side works, and the shrinkage balance can be balanced on both surfaces of the laminated film. And curling can be prevented.

The paper suitably used in this configuration is not particularly limited. For example, a double-sided coated paper having a basis weight of about 80 to 110 g / m ² and a so-called clay coat on both sides can be suitably used. . Such coated paper contributes to curling prevention because it has an appropriate thickness and rigidity.

  In addition, as a water retention agent to be supplied to paper, a water retention agent mainly composed of water, alcohols, polyethyleneimine, etc. can be used, and as alcohols, methanol, ethanol, isopropyl alcohol, butanol, etc. should be used. Can do. A method of supplying such a water retaining agent to paper is to use a solid plate in the first unit using a multicolor gravure printing machine when printing characters, designs, etc. on the outer surface of the paper, for example, by gravure printing. Print the water retention agent, dry excess water and alcohol, and then supply the water retention agent to the paper inline with the outer surface printing by printing characters, designs, etc. and overprint varnish. Can do.

  Moreover, as a pigment used for the light-shielding ink laminated | stacked on the inner surface side of paper, a black pigment like carbon black, for example can be used individually or in combination with this black pigment and a white pigment. As the white pigment, titanium dioxide, zinc white, calcium carbonate, clay (kaolin), barium sulfate and the like can be used. In addition, organic pigments or inorganic pigments can be used in appropriate combination with the pigment.

<V> Production of Lid Material The lid material of the present invention is produced by punching the laminated film obtained as described above in accordance with the shape of the flange provided around the opening of the container.
In actual manufacturing, in addition to being manufactured as a single-sheet lid material punched in advance according to the shape of the opening of the container, the wound lid material is supplied to the filling seal device to fill the contents. In many cases, it is manufactured by a method of punching into individual shapes in-line after heat-sealing to the flange at the periphery of the opening of the container, and any method can be used.
In the production of the lid material, the laminated film is previously subjected to the heat embossing method, and the irregular pattern of any shape is shaped into a shape in which the outer surface side of the lid material is convex and the inner surface side is concave. Because of this, even if the cover material punched or punched into sheets is stacked, the contact area between the cover materials is reduced, so there is no blocking, and the sliding property between the front and back surfaces of the cover material is improved. Therefore, even if it is used in an automatic filling and sealing machine that uses a single-wafer-type lid material, the lid material is suitable for feeding and can be used satisfactorily without trouble such as inserting two sheets.

Such a concavo-convex pattern is provided in order to improve the blocking resistance of the cover material and the feeding suitability of the cover material filling and sealing machine in the case of a single wafer form, and the shape of the concavo-convex pattern is particularly limited. Any shape can be used as long as a gap is formed between the cover materials that overlap each other in a wound form or in a single-wafer form, the contact area can be reduced, and the slipperiness of the stacked cover materials is not impaired. Can be provided.
It is not necessary to increase the difference in height between the concavo-convex portions. In particular, in the case where the concavo-convex pattern has a fine texture, a line, etc., it is sufficient if it is about 5 to 25 μm.
Moreover, the method of providing an uneven | corrugated pattern can be easily provided by the well-known embossing method.

In order to manufacture a package using the lid material of the present invention, the surface of the sealant layer of the lid material is overlapped so as to face the flange portion of the container filled with the contents, and heat sealed.
Examples of the contents enclosed in the package include, but are not limited to, various foods and drinks, chemical products such as liquid detergents, cosmetics, pharmaceuticals, miscellaneous goods, industrial members, and the like.
Moreover, as said container, the container which consists of various shapes, such as various square shape, a round shape, a pyramid shape, a cone shape, can be used according to the objective, a use, etc.
In the present invention, the heat sealing method between the lid member and the container can be performed by a known method such as a bar seal, a rotary roll seal, a belt seal, an impulse seal, a high frequency seal, an ultrasonic seal, and the like. .

<VI> Biomass Degree “Biomass Degree” is an index that represents the mixing ratio of petroleum-derived raw materials and plant-derived raw materials (biomass), and is determined by measuring the concentration of radioactive carbon (C ¹⁴ ). Is represented by the following formula.
Biomass degree (%) = C ¹⁴ concentration (pMC) × 0.935

The C ¹⁴ is during a plant-derived raw material include a constant concentration, hardly present in petroleum trapped underground. Therefore, by measuring the C ¹⁴ concentration by accelerator mass spectrometry, it can be used as an index of the content ratio of plant-derived raw materials.
The laminated film constituting the cover material of the present invention contains a plant-derived raw material at a high blending ratio while exhibiting high punchability and impact resistance, and has a high degree of biomass of at least 18%, for example, about 18% to 60%. Can be shown. When the degree of biomass exceeds 60%, various physical properties may be impaired as compared with petroleum-derived products.

In the present invention, the C ¹⁴ concentration in the film is measured as follows. That is, the sample to be measured is burned to generate carbon dioxide, and the carbon dioxide purified in the vacuum line is reduced with hydrogen using iron as a catalyst to purify graphite. Then, this graphite is mounted on a C ¹⁴ -AMS dedicated device (manufactured by NEC) based on a tandem accelerator, and C ¹⁴ count, C ¹³ concentration (C ¹³ / C ¹² ), C ¹⁴ concentration ( was measured in the C ¹⁴ / C ^12), calculates the ratio of the C ¹⁴ concentration of the sample carbon to standard modern carbon from the measurement value. As a standard sample, oxalic acid (HOXII) provided by the National Bureau of Standards (NIST) is used.
Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples.

[Example 1]
As a resin composition for forming a polyethylene resin layer, plant-derived LLDPE (Brasske SA SLL118, density 0.916 kg / m ³ , MFR 1.0 g / 10 min, biomass degree 87%) 50% by mass, Oil-derived LDPE (UBE Maruzen Polyethylene Co., Ltd. UBE polyethylene ^(R) F120N, density 0.920 kg / m ³ , MFR 1.2 g / 10 min) 25% by mass, and petroleum-derived LLDPE (Mitsui Chemicals, Inc.) EVOLUE ^(R) SP2020, a copolymer of ethylene and 1-hexene (C6-LLDPE), a density 0.916kg / m ^3, MFR2.3g / 10 min) blended with 25% by weight, and melt-kneading, the An inventive resin composition was obtained.

On the other hand, as a resin composition for forming an easy peel layer, a polymer blend (Toyomelt ER-6100A manufactured by Toyo Adre Co., Ltd., density 0.94 g / cm ³ , MFR 9 g / 10 min) obtained by kneading LLDPE, polybutene and polystyrene. Prepared.
Next, the resin composition of the present invention and the polymer blend are coextruded by a multilayer inflation machine, and a sealant film (biomass degree) having a configuration of a polyethylene resin layer (thickness 40 μm) / easy peel layer (thickness 10 μm) 35%).

Adhering the obtained sealant film to a plant-derived biaxially stretched PET film (thickness 12 μm, biomass degree 20%) and a vapor-deposited film in which a vapor-deposited film of silicon oxide is laminated on the plant-derived biaxially stretched PET film The laminated film (plant-derived biaxially stretched PET film / adhesive / deposited film / adhesive / sealant film) constituting the lid material of the present invention was obtained by dry lamination through the agent layer.
The biomass degree of the entire laminated film was about 32%.

Next, this laminated film was punched out in a shape having a circular shape with a diameter of 100 mm and a knob piece provided on a part of the outer periphery to produce a single-wafer cover material. At the time of punching, the laminated film showed excellent punchability, the film did not stretch, and the cut end face was beautiful.
Using this laminated film as a lid, the water is sealed on a flange of a polypropine cup container filled with water with a flat seal under conditions of a seal temperature of 200 ° C., a seal pressure of 1 kg / cm ² , and a seal time of 1 second. The packaging body which consists of a cup container filled with is produced. After sealing, there was no leakage of the package contents or tearing of the lid.
Furthermore, a drop test from a height of 1 m was performed three times, but no tearing, leakage, etc. were observed on the lid. Further, when the lid member was peeled from the container, the easy peel layer was agglomerated and broken, and the lid member could be peeled with a good peel feeling.
Moreover, when the line seal (ring seal) performed at high pressure was performed, the sealant layer was not broken and showed a very stable peel behavior.

[Example 2]
In the same manner as in Example 1, the resin composition and polymer blend of the present invention were prepared.
Further, a low melting point polypropylene resin (Nippon Polypro Co., Ltd. Wing WFX4TA, density = 0.900 g / cm ³ , MFR = 7.0 g / 10 min) was prepared as a resin for forming the heat seal layer.
Next, the above resin composition, polymer blend, and low melting point polypropylene resin of the present invention were coextruded by a three-layer three-layer top-blown air-cooled inflation coextrusion film forming machine, and a polyethylene resin layer (thickness 22 μm) / easy peel layer A sealant film (biomass degree 32%) having a total thickness of 30 μm having a three-layer structure of (thickness 5 μm) / heat seal layer (thickness 3 μm) was formed.
The obtained sealant film was dry-laminated with the plant-derived biaxially stretched PET film and the vapor-deposited film in the same manner as in Example 1, to form a laminated film (plant-derived biaxially stretched PET film / Adhesive / deposition film / adhesive / sealant film) was obtained.
The biomass degree of the entire laminated film was 29%.

Next, in the same manner as in Example 1, a cover material and a package of the present invention were produced using this laminated film.
At the time of punching, the laminated film showed excellent punchability, the film did not stretch, and the cut end face was beautiful. In addition, leakage of the package contents and tearing of the lid were not observed.
Furthermore, a drop test from a height of 1 m was performed three times, but no tearing, leakage, etc. were observed on the lid. Further, when the lid member was peeled from the container, the easy peel layer was agglomerated and broken, and the lid member could be peeled with a good peel feeling.
Moreover, when the line seal (ring seal) performed at high pressure was performed, the sealant layer was not broken and showed a very stable peel behavior.

1 Base Material Layer 2 Sealant Layer 3 Polyethylene Resin Layer 4 Easy Peel Layer 5 Heat Seal Layer

Claims (4)

A cover material comprising a laminated film having at least a base material layer and a sealant layer,
The sealant layer is a layer made of a sealant film obtained by coextrusion laminating at least a polyethylene resin layer and an easy peel layer,
The easy peel layer is a layer made of a polymer blend containing at least two kinds of resins,
The polyethylene-based resin layer is located between the base material layer and the easy peel layer, and includes the following components:
(A) 20-70 mass% of linear low density polyethylene derived from a plant,
(B) 15-65% by mass of non-plant-derived low-density polyethylene having physical properties of a density of 0.920 to 0.933 kg / m ³ and an MFR of 0.5 to 3.5 g / 10 min.
(C) obtained by copolymerization of ethylene and an α-olefin having 6 carbon atoms and having physical properties of a density of 0.914 to 0.937 kg / m ³ and MFR of 0.9 to 3.0 g / 10 min. Non-plant derived linear low density polyethylene 15-65% by weight, and (d) optional additive 0-20% by weight,
A layer composed of a polyethylene resin composition, wherein the total of (a) to (d) is 100% by mass,
The said cover material characterized by the compounding quantity of this polyethylene-type resin composition with respect to this whole sealant film being 50 mass% or more.   The sealant layer is a layer made of a sealant film obtained by coextrusion laminating the polyethylene resin layer, the easy peel layer, and the heat seal layer serving as the innermost layer in this order. The lid material described.   The said base material layer is a layer which consists of a polyethylene terephthalate film whose biomass degree consisting of a plant-derived raw material is 15 to 100%, The lid | cover material of Claim 1 or 2 characterized by the above-mentioned.   The cover material according to claim 1, wherein the biomass degree of the entire cover material is at least 18%.

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