JP2008087357A - Film for deep drawing, bottom material for deep drawing packaging, and deep drawing packaging - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a deep drawing film which is excellent in packing mainly foodstuffs such as sliced ham or sliced bacon and has excellent gas barrier properties/heat sealability, toughness/gloss, transparency and deep drawing properties as a film. <P>SOLUTION: This deep drawing film comprises at least, one thermoplastic resin layer as an external layer, at least, one polylactic acid (PLA)-based resin layer and a polyamide resin (PA) layer as an intermediate layer, and a heat-sealable resin layer as an internal layer. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention mainly relates to a deep drawing film suitable for packaging sliced ham, sliced bacon and the like, a bottom material for a deep drawing package, and a deep drawing package.

  Sliced ham, sliced bacon and the like are usually stored and distributed and sold in a deep-drawn package. Such a deep-drawn package is obtained, for example, by joining a bottom material having a cylindrical recess at the center of a pack product and a lid material by heat sealing or the like. Sliced ham or the like is accommodated in the recess.

  Conventionally, as a bottom material for a deep-drawn package, a polyester resin (hereinafter referred to as “PEs”) is provided as an outer layer, and a nylon resin (Ny) and a saponified ethylene-vinyl acetate copolymer (EVOH) are provided as an intermediate layer. However, multilayer films having a cohesive failure type easy peel layer as the innermost sealing layer have been widely used. The reason is that the deep-drawn package having this configuration has a good waist (rigidity), is excellent in gloss and transparency, and has a very good appearance.

  However, PEs used as an outer layer show a large bending rigidity compared to polyolefin resin, but the rigidity is insufficient as a deep drawing packaging material, and the flange portion (bottom material film and The heat seal portion with the lid material film, and the portion where the pack contents do not exist) was easily curled. Even if you try to keep the flange flat by setting the conditions at the time of packing, depending on the packing conditions and the configuration of the lid material, it tends to curl on the lid side or curl on the bottom side. Setting was very difficult. Also, PEs have a relatively high viscosity at room temperature, so troubles that cannot be cut well depending on the state of the cutting blade of the deep-drawing packaging machine are likely to occur frequently. Was used. For these reasons, there has been a demand for a film for deep drawing, which is more rigid than a film using PEs, is excellent in gloss and transparency, and has good deep drawing formability.

  In recent years, the effective use of exhaustible resources has been emphasized, and the use of renewable resources has become an important issue. Plant raw material plastics are attracting the most attention as renewable resources in containers and packaging. This plant-based plastic not only uses non-depleting resources, but can not only save depleting resources during plastic production, but also has excellent recyclability.

  Among plant-derived plastics, polylactic acid resin (hereinafter referred to as “PLA”) using lactic acid obtained by fermentation of starch as a raw material can be mass-produced by chemical engineering, and has excellent transparency and rigidity. Therefore, it has attracted attention in the field of film packaging and injection molding as an alternative material for polystyrene and aromatic polyester (polyethylene terephthalate), and is also expected as a film material for deep drawing.

  However, since PLA has insufficient heat resistance compared with PEs, a phenomenon called hot plate tray may occur in the sealing process of a deep drawing packaging machine. That is, when sealing with a deep-drawing packaging machine using a deep-drawing bottom material having a PLA layer as an outer layer, the upper hot plate comes into contact with the bottom material previously placed on the lower packing mold. When the hot plate comes into contact with the packing, the heat of the hot plate is transferred to the packing, the packing has heat, the outer layer side of the bottom material is taken up by the hot plate, and as a result, the surface gloss is lowered. It occurred frequently (hereinafter referred to as “packing tray”). In addition, there is a method of setting the seal temperature low in order to prevent such packing trail, but there is a drawback that the temperature range is narrow and it is difficult to set the easy peel strength.

Further, PLA has a problem in using PLA itself as a material for a packaging film because it has insufficient barrier properties such as gas and water vapor and has poor heat sealability. As means for solving this problem, a film in which PLA is coated with polyvinyl alcohol has been proposed for the purpose of improving gas barrier properties (see Patent Documents 1 and 2). It has also been proposed to laminate an ethylene-vinyl alcohol copolymer, an ethylene-vinyl acetate copolymer, or the like on a polylactic acid resin (see Patent Documents 3, 4, and 5). Furthermore, it is also proposed to laminate a polyolefin resin to a polylactic acid resin for the purpose of imparting heat sealability (see Patent Documents 6 and 7).
Japanese Patent Laid-Open No. 08-244190 JP 2000-177072 A JP 2001-347623 A JP 2004-256570 A JP 2004-26222 A JP 2000-281813 A JP 2005-119125 A

  However, Patent Documents 1 to 7 propose a method of laminating various resins on PLA in order to improve the barrier property and the heat seal property as described above. And gloss / transparency, and deep drawability were not balanced.

  The present invention is to solve the above-mentioned problems of the prior art, and the object of the present invention is a film for deep drawing, which is excellent in film stiffness, gloss and transparency, and excellent in deep drawability. Is to provide.

  Furthermore, another object of the present invention is to provide a bottom material for a deep drawn package and a deep drawn package comprising the film for deep drawing of the present invention.

  In order to solve the above-mentioned problems, the present invention has been intensively studied on the materials and layer structures constituting the deep drawing film. As a result, it was found that by forming a film in which layers composed of a predetermined composition were combined, it was possible to obtain film stiffness, excellent gloss / transparency, and deep drawability, and the present invention was completed. .

  That is, an object of the present invention is to have at least one thermoplastic resin layer as an outer layer, at least one PLA layer and a polyamide resin (hereinafter also referred to as “PA”) layer as an intermediate layer, and a heat-sealable resin layer as an inner layer. This is solved by a film for deep drawing (hereinafter also referred to as “first invention”).

  The deep drawing film preferably has at least one saponified ethylene-vinyl acetate copolymer (hereinafter also referred to as “EVOH”) layer as an intermediate layer.

  The deep drawing film may further include at least one ethylene-vinyl acetate copolymer (hereinafter also referred to as “EVA”) layer or polyethylene (hereinafter also referred to as “PE”) layer as an intermediate layer. preferable.

  The deep drawing film preferably further includes at least one adhesive resin layer as an intermediate layer.

The heat-sealable resin layer of the deep drawing film is composed of any of the following resin composition A, resin composition B, and a mixture of resin composition A and resin composition B. Is preferred.
Resin composition A: Main component is linear low density polyethylene (LLDPE), ethylene-vinyl acetate copolymer (EVA), ethylene-acrylic acid copolymer (EAA), ethylene-ethyl acrylate copolymer (EEA) ), Ethylene-methacrylic acid copolymer (EMAA), ethylene-methyl methacrylate copolymer (EMMA), ethylene-methyl acrylate copolymer (EMA), ethylene-acrylic acid copolymer (EAA) and ethylene -Resin composition selected from the group consisting of ionomers of ethyl acrylate copolymer (EEA) or a mixture thereof Resin composition B: resin whose main component is polypropylene (PP) or polybutene-1 (PB-1) Composition or mixture thereof

  In the present specification, the term “main component” is intended to allow other components to be included within a range that does not hinder the action and effect of the resin constituting each layer. Furthermore, the term “main component” occupies 50% by mass or more, preferably 70% by mass or more, more preferably 80% by mass or more, and further preferably 90% by mass or more and 100% by mass or less of the total components of each layer. It is an ingredient.

  The seal strength of the heat-sealable resin layer is preferably 0.8 N / 15 mm width or more and 40 N / 15 mm width or less at 25 ° C.

  In addition, the second problem of the present invention is solved by a bottom material for a deep-drawn package body formed of the above composite film.

  The third problem of the present invention is solved by a deep drawn package using the above-described deep drawn packaging bottom material.

  ADVANTAGE OF THE INVENTION According to this invention, the film excellent in the waist and transparency of a film which does not drop surface gloss with a deep drawing packaging machine is provided. Since this film has excellent rigidity, curling at the flanges of packed products is less likely to occur when deep-drawn packaging is performed, and it also shows good cutability when film is cut by a deep-drawing packaging machine. Excellent in deep drawability. Therefore, it can be suitably used as a deep drawing film, particularly as a bottom material of a deep drawing package. Furthermore, the film of this invention has the polylactic acid-type resin layer which is plant raw material plastics, and is excellent also in environmental suitability.

  Such an operation and gain of the present invention will be made clear from the best mode for carrying out the invention described below.

  The deep drawing film of the present invention has at least one thermoplastic resin as an outer layer, and has at least one PLA layer and a polyamide resin (hereinafter also referred to as “PA”) layer as an intermediate layer, and an inner layer. And a heat-sealable resin layer. Here, the outer layer is a layer that becomes the outermost side of the bottom material of the packed product when it is a deep-drawn package, and the inner layer is in contact with the contents when it is a deep-drawn package, and It is a layer that constitutes the joint surface with the lid member, and the intermediate layer refers to one or two or more layers provided between the outer layer and the inner layer.

  Hereinafter, a film for deep drawing of the present invention (hereinafter also referred to as “film of the present invention”), a bottom material for deep-drawing packaging formed from the film, and a deep-drawing packaging body using the bottom material (hereinafter “ The bottom material of the present invention and the package of the present invention ”) will be described in detail.

[Film for deep drawing]
1. Outer layer The outer layer of the film of the present invention comprises at least one thermoplastic resin. The thermoplastic resin is not particularly limited as long as it has a good appearance as a bottom material for deep-drawing packaging and has a glossy finish. However, it is preferable that the thermoplastic resin has heat resistance and can avoid packing trays in the sealing process.

  Examples of the thermoplastic resin include low density polyethylene (LDPE), linear low density polyethylene (LLDPE), m-linear low density polyethylene (m-LLDPE), high density polyethylene (HDPE), and ethylene-acetic acid. Vinyl copolymer (EVA), ethylene-ethyl acrylate copolymer (EEA), ethylene-methyl acrylate copolymer (EMA), ethylene-vinyl acetate copolymer (EVA), ethylene-ethyl acrylate ( Polyethylene resins such as EEA) and ethylene-methyl acrylate copolymer (EMA) ionomers; polypropylene resins such as homopolypropylene and random polypropylene; 6 nylon, 66 nylon, 69 nylon, 6-66 nylon, 12 nylon 11 nylon, 610 nylon, 612 Nylon, 6I-6T nylon, polymers or copolymers of two or more of these condensation units such as MXD6 nylon, more and polyamide-based resin consisting of a mixture thereof. Among them, it is preferable to use 6 nylon or 6-66 nylon.

  Also, as the thermoplastic resin, polyester resins such as polyethylene terephthalate (PET), polyethylene terephthalate glycol copolymer (PETG), polybutylene terephthalate (PBT), and saponified ethylene-vinyl acetate copolymer (EVOH) are also used. can do.

  The above thermoplastic resins may be used alone or in combination of two or more. The outer layer of the present invention may be at least one layer, and may be two or more thermoplastic resin layers composed of different types of thermoplastic resins.

  The thickness of the outer layer of the present invention is not particularly limited, but is desirably 2 μm or more, preferably 5 μm or more. If the thickness of the outer layer is 2 μm or more, there is an effect of suppressing packing trays. On the other hand, the upper limit of the thickness of the outer layer is not particularly limited, but is desirably 30 μm or less, preferably 20 μm or less, and more preferably 15 μm or less from the viewpoint of imparting each function to the entire thickness.

2. Intermediate layer <PLA layer>
The intermediate layer of the film of the present invention includes at least one PLA layer. PLA refers to a homopolymer of D-lactic acid or L-lactic acid or a copolymer thereof. Specifically, poly (D-lactic acid) whose structural unit is D-lactic acid, and whose structural unit is L-lactic acid. And poly (DL-lactic acid), which is a copolymer of L-lactic acid and D-lactic acid, and a mixture thereof.

  In the PLA used in the present invention, the constituent ratio of D-lactic acid and L-lactic acid is D-lactic acid: L-lactic acid = 100: 0 to 85:15, or D-lactic acid: L-lactic acid = 0. Is preferably 100 to 15:85, and more preferably D-lactic acid: L-lactic acid = 99.5: 0.5 to 95: 5, or D-lactic acid: L-lactic acid = 0.5: 99.5-5: 95. By adjusting the composition ratio of D-lactic acid and L-lactic acid within this range, molding stability of the resulting film can be obtained.

  A polylactic acid polymer in which the constituent ratio of D-lactic acid and L-lactic acid is 100: 0 or 0: 100 becomes a crystalline resin, has a high melting point, and tends to be excellent in heat resistance and mechanical properties. On the other hand, in the case of a copolymer of DL-lactic acid, it is known that the crystallinity decreases as the proportion of the optical isomer increases. Therefore, it is possible to obtain good molding stability by adjusting the crystallinity within the range described above.

  In the present invention, PLAs having different copolymerization ratios of D-lactic acid and L-lactic acid may be blended. In this case, the average value of DL ratios of a plurality of PLAs may be set within the above range. By blending two or more types of PLAs having different DL ratios and adjusting the crystallinity according to the intended use, it is possible to balance the moldability and other characteristics.

  The PLA may be a copolymer of lactic acid and an α-hydroxycarboxylic acid, an aliphatic diol, or an aliphatic dicarboxylic acid as long as the effects of the present invention are not impaired.

  Examples of the α-hydroxycarboxylic acid unit include glycolic acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 2-hydroxy-n-butyric acid, 2-hydroxy-3,3-dimethylbutyric acid, and 2-hydroxy-3-methylbutyric acid. , Bifunctional aliphatic hydroxycarboxylic acids such as 2-methyllactic acid and 2-hydroxycaproic acid, and lactones such as caprolactone, butyrolactone and valerolactone.

  Examples of the diol unit include ethylene glycol, 1,4-butanediol, 1,4-cyclohexanedimethanol and the like. Examples of the dicarboxylic acid unit include succinic acid, adipic acid, suberic acid, sebacic acid, and dodecanedioic acid.

  The copolymerization ratio in the copolymer of lactic acid and α-hydroxycarboxylic acid is not particularly limited, but the higher the proportion of lactic acid, the more preferable is the consumption of petroleum resources. Specifically, the copolymerization ratio of lactic acid and a copolymer of α-hydroxycarboxylic acid, aliphatic diol, or aliphatic dicarboxylic acid is lactic acid: α-hydroxycarboxylic acid, aliphatic diol, or aliphatic dicarboxylic acid = 95: 5 to 10:90, preferably 90:10 to 20:80, and more preferably 80:20 to 30:70. If the copolymerization ratio is within the above range, a film having a good balance of physical properties such as rigidity, transparency and impact resistance can be obtained.

  The weight (mass) average molecular weight of the PLA is 20,000 or more, preferably 40,000 or more, more preferably 60,000 or more, and the upper limit is 400,000 or less, preferably 350,000 or less, more preferably. 300,000 or less. When the weight (mass) average molecular weight is 20,000 or more, an appropriate resin cohesive force can be obtained, and the film can be prevented from being insufficiently stretched or embrittled. On the other hand, if the weight (mass) average molecular weight is 400,000 or less, the melt viscosity can be lowered, which is preferable from the viewpoint of production and productivity improvement.

  As the PLA polymerization method, known methods such as a condensation polymerization method and a ring-opening polymerization method can be employed. For example, in the case of a condensation polymerization method, PLA having an arbitrary composition can be obtained by direct dehydration condensation polymerization of D-lactic acid, L-lactic acid, or a mixture thereof. Further, in the ring-opening polymerization method, a lactide which is a cyclic dimer of lactic acid is subjected to ring-opening polymerization in the presence of a predetermined catalyst while using a polymerization regulator or the like, if necessary. A lactic acid resin can be obtained. The lactide includes DL-lactide, which is a dimer of L-lactic acid, and PLA having any composition and crystallinity can be obtained by mixing and polymerizing these as necessary. Furthermore, a small amount of chain extender such as a diisocyanate compound, diepoxy compound, acid anhydride, acid chloride, etc. may be used for the purpose of increasing the molecular weight.

  Examples of the commercial products of PLA include “Nature Works (registered trademark)” (manufactured by Nature Works LLC), “LACEA (registered trademark)” (manufactured by Mitsui Chemicals, Inc.), and the like.

  In the present invention, a soft resin may be added to the PLA layer for the purpose of further improving various properties such as impact resistance, molding processability, and adhesiveness as long as the effects of the present invention are not significantly impaired.

  Although it does not specifically limit as a soft resin, Aliphatic polyester other than PLA, Aromatic aliphatic polyester, Copolymer of diol, dicarboxylic acid, and lactic acid resin, Core shell structure type rubber, Ethylene-vinyl acetate Copolymer (EVA), ethylene-acrylic acid copolymer (EAA), ethylene-ethyl acrylate copolymer (EEA), ethylene- (meth) acrylic acid copolymer (EMA), ethylene-methyl (meth) An acrylic acid copolymer (EMMA) etc. can be used conveniently. Among these, core-shell structure rubber can be used more suitably.

  Examples of the aliphatic polyester include polyhydroxycarboxylic acid, aliphatic polyester obtained by condensing aliphatic diol and aliphatic dicarboxylic acid, aliphatic polyester obtained by ring-opening polymerization of cyclic lactone, and synthetic system An aliphatic polyester etc. can be mentioned.

  Examples of the polyhydroxycarboxylic acid include 3-hydroxybutyric acid, 4-hydroxybutyric acid, 2-hydroxy-n-butyric acid, 2-hydroxy-3,3-dimethylbutyric acid, 2-hydroxy-3-methylbutyric acid, and 2-methyllactic acid. , Homopolymers and copolymers of hydroxycarboxylic acids such as 2-hydroxycaprolacuronic acid.

  As the aliphatic polyester obtained by condensing the aliphatic diol and the aliphatic dicarboxylic acid, one or two or more kinds of aliphatic polyesters and aliphatic dicarboxylic acids described below are condensed. Alternatively, a polymer that can be obtained as a desired polymer by jumping up the molecular weight with an isocyanate compound or the like, if necessary, can be mentioned.

  Here, typical examples of the aliphatic diol include ethylene glycol, propylene glycol, 1,4-butanediol, 1,4-cyclohexanedimethanol, and the like. Examples of the aliphatic dicarboxylic acid include succinic acid, adipic acid, suberic acid, sebacic acid, dodecanedioic acid, and the like.

  Examples of the aliphatic polyester obtained by ring-opening condensation of the above-mentioned cyclic lactones include ring-opening polymers such as ε-caprolactone, σ-valerolactone, and β-methyl-σ-valerolactone, which are cyclic monomers. Can be mentioned. The cyclic monomer can be copolymerized by selecting not only one kind but also plural kinds.

  Furthermore, examples of the synthetic aliphatic polyester include a copolymer of a cyclic acid anhydride and an oxirane, such as a copolymer of succinic anhydride and ethylene oxide, a copolymer of propion oxide, and the like. it can.

  Typical examples of these aliphatic polyesters other than PLA include “Bionore (registered trademark)” (manufactured by Showa Polymer Co., Ltd.) obtained by polymerizing succinic acid, 1,4-butanediol and adipic acid. ) Etc. can be obtained commercially. Moreover, as a thing obtained by ring-opening condensation of (epsilon) -caprolactone, "Cell Green (trademark)" (made by Daicel Chemical Industries Ltd.) etc. are mentioned.

  Next, as the aromatic aliphatic polyester, those having crystallinity lowered by introducing an aromatic ring between aliphatic chains can be used. The aromatic aliphatic polyester is obtained, for example, by condensing an aromatic dicarboxylic acid, an aliphatic dicarboxylic acid, and an aliphatic diol.

  Examples of the aromatic dicarboxylic acid include isophthalic acid, terephthalic acid, 2,6-naphthalenedicarboxylic acid, and terephthalic acid is most preferably used. Examples of the aliphatic dicarboxylic acid include succinic acid, adipic acid, suberic acid, sebacic acid, dodecanedioic acid, and adipic acid is most preferably used. Furthermore, examples of the aliphatic diol include those described above. Two or more types of aromatic dicarboxylic acids, aliphatic dicarboxylic acids or aliphatic diols may be used.

  Typical examples of the aromatic aliphatic polyester include a copolymer of tetramethylene adipate and terephthalate, a copolymer of polybutylene adipate and terephthalate, and the like. "EasterBio (registered trademark)" (manufactured by Eastman Chemical Co., Ltd.) as a copolymer of tetramethylene adipate and terephthalate, and "Ecoflex (registered trademark)" (manufactured by BASF) as a copolymer of polybutylene adipate and terephthalate. It can be obtained commercially.

  Examples of the structure of the diol / dicarboxylic acid / lactic acid copolymer include a random copolymer, a block copolymer, and a graft copolymer, and any structure may be used. However, from the viewpoint of impact resistance and transparency of the film, block copolymers and graft copolymers are preferred. Specific examples of the random copolymer include “GSPla (registered trademark)” (manufactured by Mitsubishi Chemical Corporation), and specific examples of the block copolymer or graft copolymer include “Plamate (registered trademark)”. (Dainippon Ink Chemical Co., Ltd.).

  The method for producing the copolymer of diol, dicarboxylic acid and lactic acid is not particularly limited. For example, a polyester or polyether polyol having a structure obtained by dehydrating condensation of diol and dicarboxylic acid is subjected to ring-opening polymerization or lactide. The method obtained by carrying out transesterification is mentioned. Another example is a method in which a polyester or polyether polyol having a structure obtained by dehydration condensation of a diol and a dicarboxylic acid is obtained by dehydration / deglycolization condensation or transesterification with a polylactic acid resin.

  The copolymer of diol, dicarboxylic acid and lactic acid can be adjusted to a predetermined molecular weight using an isocyanate compound or a carboxylic acid anhydride. However, from the viewpoints of workability and mechanical properties, the weight (mass) average molecular weight is 50,000 or more, preferably 100,000 or more, and 300,000 or less, preferably 250,000 or less. .

  Moreover, the said core-shell structure rubber means the rubber-like component which has a two-layer structure of a core part and a shell part. This core-shell structure rubber has a high impact resistance improving effect and is finely dispersed in the PLA component by being combined with PLA, so that the impact resistance can be greatly improved without substantially impairing the transparency of the PLA.

  Examples of the core-shell rubber include diene-based core-shell type polymers such as methacrylic acid-butadiene copolymer, acrylonitrile-butadiene-styrene copolymer, acrylic core-shell type polymers such as methacrylic acid-styrene-acrylonitrile copolymer, And silicone-based core-shell copolymers such as silicone-methacrylic acid-methylmethacrylic acid copolymer and silicone-methacrylic acid-acrylonitrile-styrene copolymer.

  Specific examples of such products include “Metablene (registered trademark) C.S.E.W.” (manufactured by Mitsubishi Rayon Co., Ltd.) and “Kane Ace (registered trademark)” (manufactured by Kaneka Corporation). Available at:

  Among these core-shell structured rubbers, a silicone-methacrylic acid-methylmethacrylic acid copolymer which has good compatibility with PLA and can balance the impact resistance and transparency of the film is more preferably used. This silicone-acrylic composite rubber has excellent low-temperature properties and a high impact resistance improving effect, and because it is finely dispersed in PLA by compounding with acrylic, it greatly improves impact resistance without substantially losing PLA transparency. Can be improved.

  This silicone acrylic composite rubber has a core-shell structure. As a specific example, the core portion is made of a copolymer of a siloxane compound and a (meth) acrylic monomer, and the shell portion is made of a homopolymer or copolymer of a (meth) acrylic monomer. Is mentioned.

  Examples of the siloxane compound include dimethylsiloxane. Moreover, as a (meth) acrylic-type monomer used for a core part, butyl (meth) acrylate, 2-ethylhexyl acrylate, etc. are mentioned. Furthermore, examples of the (meth) acrylic monomer used for the shell part include methyl (meth) acrylate.

  In the present specification, “(meth) acryl” means “acryl or methacryl”.

  When the silicone acrylic composite rubber having the above core-shell structure is used, since the shell portion has a polymer composed of a (meth) acrylic monomer, the core portion is composed of a polymer composed of the (meth) acrylic monomer. It has high affinity and high affinity with PLA disposed on the outside of the silicone acrylic composite rubber. For this reason, the silicone-acrylic composite rubber can have a stable core-shell structure, and can stably maintain a dispersed state in the mixed resin.

  As a specific example of the silicone acrylic composite rubber, “Metabrene (registered trademark) S-2001” (manufactured by Mitsubishi Rayon Co., Ltd.) can be mentioned.

  In addition, the ethylene-vinyl acetate copolymer (EVA), ethylene-acrylic acid copolymer (EAA), ethylene- (meth) acrylic acid ester copolymer (EMA), ethylene-methyl (meth) acrylic acid ester As the copolymer (EMMA), those having a comonomer content other than ethylene of 20% by mass or more, preferably 40% by mass or more, and 90% by mass or less, preferably 80% by mass are suitably used. If the comonomer content other than ethylene is 20% by mass or more, the effect on the rupture resistance of the film can be sufficiently obtained, and transparency can be maintained, which is preferable. On the other hand, if it is 90 mass% or less, since the rigidity and heat resistance of the whole film can be maintained favorable, it is preferable. Among these, ethylene-vinyl acetate copolymer (EVA) is more preferably used.

  Examples of the ethylene-vinyl acetate copolymer (EVA) include “EVAFLEX (registered trademark)” (manufactured by Mitsui DuPont Polychemical Co., Ltd.) and “Novatech (registered trademark) EVA” (manufactured by Mitsubishi Chemical Corporation). "Ebaslen (registered trademark)" (manufactured by Dainippon Ink and Chemicals, Inc.), "Evalate (registered trademark)" (manufactured by Sumitomo Chemical Co., Ltd.), "Soabrene (registered trademark)" (Nippon Synthetic Chemical Industry) Etc.) are commercially available.

  As the ethylene-acrylic acid copolymer (EAA), “Novatech (registered trademark) EAA” (manufactured by Mitsubishi Chemical Corporation) and the like are commercially available. Further, as the ethylene- (meth) acrylic acid copolymer (EMA), “Elvalloy AC (registered trademark)” (manufactured by Mitsui DuPont Polychemical Co., Ltd.) and the like are commercially available. Furthermore, as an ethylene-methyl (meth) acrylic acid copolymer (EMMA), “ACRIFT (registered trademark)” (manufactured by Sumitomo Chemical Co., Ltd.) and the like are commercially available.

  When the above-mentioned soft resin is added to the PLA layer, the preferable content thereof is 5% by mass or more, preferably 10% by mass or more, more preferably 15% by mass or more, and 30% by mass or less, preferably 25% by mass. % Or less, more preferably 20% by mass or less.

  The thickness of the PLA layer is not particularly limited, but is 5 μm or more, preferably 15 μm or more, more preferably 20 μm or more, and the upper limit is 100 μm or less, preferably 80 μm or less, more preferably 60 μm or less. If the thickness is 20 μm or more, the occurrence of curling in the flange portion of the package can be suppressed, and if the upper limit is 100 μm or less, the film does not become too hard and good deep drawing formability can be obtained. it can.

<PA layer>
The intermediate layer of the film of the present invention has at least one PA layer for the purpose of imparting pinhole resistance and deep drawability. PA used in the intermediate layer is not particularly limited, but nylon-based resin (Ny) is preferably used from the viewpoint of pinhole resistance. Examples of the nylon resin include polymers of condensation units such as 6 nylon, 66 nylon, 69 nylon, 6-66 nylon, 12 nylon, 11 nylon, 610 nylon, 612 nylon, 6I-6T nylon, and MXD6 nylon. A copolymer with two or more kinds, and a mixture thereof can be exemplified. Among them, it is preferable to use 6 nylon or 6-66 nylon.

  The thickness of the PA layer (total thickness when two or more layers are provided) is 2 μm or more, preferably 3 μm or more, more preferably 5 μm or more, and the upper limit is 30 μm or less, preferably 20 μm or less, more preferably 15 μm or less. . By setting the lower limit of the thickness of the PA layer to 2 μm or more, good pinhole resistance can be obtained, and by setting the upper limit to 30 μm, the cutability and thermoformability of the film can be maintained well.

<EVOH layer>
As the intermediate layer, at least one EVOH layer can be provided for the purpose of imparting oxygen barrier properties. The ethylene content of EVOH used in the EVOH layer is not particularly limited, but is 29 mol% or more, preferably 32 mol% or more from the viewpoint of film formation stability, and the upper limit is 47 mol% or less, preferably 44 It is desirable to make it mol% or less. Further, EVOH has a saponification degree of 90% or more, preferably 95 mol% or more. By maintaining the ethylene content and saponification degree of EVOH within the above ranges, the coextrudability of the film of the present invention and the strength of the film can be improved.

  When the EVOH layer is provided, the thickness of the EVOH layer (total thickness when two or more layers are provided) is preferably 5 μm or more, preferably 8 μm or more, more preferably 10 μm or more, and the upper limit is 30 μm or less, preferably 25 μm. Hereinafter, it is more preferable that the thickness is 20 μm or less. Sufficient oxygen barrier properties can be obtained by setting the lower limit of the thickness of the EVOH layer to 5 μm, and good film strength can be maintained without deteriorating the coextrudability of the film by setting the upper limit to 30 μm. .

<EVA layer or PE layer>
As the intermediate layer, at least one EVA layer or PE layer may be provided for the purpose of imparting flexibility.

  When the EVA layer is provided in the intermediate layer, the vinyl acetate content of EVA is not particularly limited, but is 1% by mass or more, preferably 3% by mass or more, and the upper limit is 15% from the viewpoint of film formation stability. It is desirable that the content be 10% by mass or less, preferably 10% by mass or less.

  Moreover, when providing a PE layer in an intermediate | middle layer, PE used by PE layer is not specifically limited, For example, linear low density polyethylene (LLDPE), low density polyethylene (LDPE), high density polyethylene ( HDPE) or blends thereof can be used. The blend ratio can be appropriately determined for the purpose of imparting desired flexibility.

LLDPE has a density of 0.905 g / cm ³ or higher, preferably 0.91 g / cm ³ or more, still more preferably 0.915 g / cm ³ or more, 0.94 g / cm ³ or less, preferably 0.93 g / cm ³ or less, more preferably 0.925 g / cm ³ or less. The LDPE has a density of 0.90 g / cm ³ or higher, preferably 0.91 g / cm ³ or more, still more preferably 0.915 g / cm ³ or more and 0.94 g / cm ³ or less, preferably 0. 93 g / cm ³ or less, more preferably 0.925 g / cm ³ or less. HDPE has a density of 0.93 g / cm ³ or more, preferably 0.94 g / cm ³ or more, more preferably 0.945 g / cm ³ or more, and 0.965 g / cm ³ or less, preferably 0.96 g / cm 2. cm ³ or less, more preferably 0.955 g / cm ³ the following are preferably used. By using a high-density material, moderate hardness can be imparted to the PE layer while maintaining flexibility.

  In the case of providing an EVA layer or PE layer, from the viewpoint of film forming properties, the thickness (total thickness when two or more layers are provided) is 10 μm or more, preferably 20 μm or more, more preferably 25 μm or more, and the upper limit is 100 μm. Hereinafter, it is preferably 80 μm or less, more preferably 60 μm or less.

3. Inner layer The inner layer of the film of the present invention is a layer made of a heat-sealable resin. An inner layer is a layer which comprises a joint surface with a cover material, when it is set as the bottom material of a deep drawing package as above-mentioned. The package bonded to the lid by the heat-sealable resin layer is completely sealed or easy peeled in the heat-sealable resin layer depending on the type of the pack product. Here, the complete seal means a seal type that cannot be easily opened by hand, and the easy peel means that the package product can be easily picked by picking the unbonded portion of the lid and bottom material of the pack by hand. A form that can be opened.

Specifically, as the resin used in the heat-sealable resin layer, the following resin composition A, resin composition B, or a mixture of the resin composition A and the resin composition B can be suitably used. Especially, as a heat-sealable resin layer, it is preferable to use the mixture of the resin composition A and the resin composition B, and especially an ethylene-vinyl acetate copolymer (EVA) and polybutene-1 (PB-1). It is preferable to use a mixture.
Resin composition A: Main component is linear low density polyethylene (LLDPE), ethylene-vinyl acetate copolymer (EVA), ethylene-acrylic acid copolymer (EAA), ethylene-ethyl acrylate copolymer (EEA) ), Ethylene- (meth) acrylic acid copolymer (EMAA), ethylene- (meth) methyl acrylate copolymer (EMMA), ethylene-methyl acrylate copolymer (EMA), and ethylene-acrylic acid copolymer Resin composition selected from the group consisting of an ionomer of a blend (EAA) and an ethylene-ethyl acrylate copolymer (EEA), or a mixture thereof Resin composition B: Polypropylene (PP) or polybutene-1 (main component Composition in which is polypropylene (PP) or polybutene-1 (PB-1), or a mixture thereof

  The heat-sealable resin layer may have a two-layer structure including a layer for imparting heat-sealability and a layer for imparting easy peel properties. When the heat-sealable resin layer is composed of two layers, the innermost layer (layer for imparting heat-sealability) is preferably composed of the resin composition A, particularly ethylene-vinyl acetate copolymer It is preferable to use coalescence (EVA). Further, as another layer adjacent to this (layer for imparting easy peel properties), it is preferable to use a mixture of the resin composition A and the resin composition B, and in particular, an ethylene-vinyl acetate copolymer. It is preferable to use a mixture of (EVA) and polybutene-1 (PB-1).

  The lower limit of the thickness of the heat-sealable resin layer (the total thickness in the case of a two-layer structure) is 1 μm or more, preferably 2 μm or more, more preferably 3 μm or more from the viewpoint of heat sealability and peel appearance. It is desirable to do. By setting the thickness of the heat-sealable resin layer to 3 μm or more, stable film forming properties and heat-sealability can be obtained.

  On the other hand, when the heat-sealable resin layer is a single layer, the upper limit of the thickness is desirably 15 μm or less, preferably 12 μm or less, and more preferably 10 μm or less. If the thickness of the heat-sealable resin layer is 15 μm or less, it is possible to prevent the occurrence of fuzz at the time of peeling, and a good peeling appearance can be obtained.

  In addition, when the heat-sealable resin layer has a two-layer structure as described above, the upper limit of the thickness of the innermost layer is that the thinner one has better stringiness and film breakage and is superior in peelability. The thickness is preferably as thin as possible within a range that does not deteriorate the film forming property and heat sealability, and is preferably 10 μm or less, preferably 5 μm or less, and more preferably 3 μm or less. The upper limit of the thickness of another adjacent layer is 15 μm or less, preferably 12 μm or less, more preferably 8 μm or less.

  The sealing strength of the heat-sealable resin layer is not particularly limited as long as the interlayer can be bonded with a required strength, but at an interlayer 25 ° C., the width is 0.8 N / 15 mm or more, preferably 5.9 N / 15 mm or more, more preferably 7 0.8 N / 15 mm width or more, more preferably 9.8 N / 15 mm width or more, and 40 N / 15 mm width or less, preferably 35 N / 15 mm width or less, more preferably 30 N / 15 mm width or less, more preferably 25 N / 15 mm. Below the width.

  Moreover, when giving an easy peel property to the heat-sealable resin layer of the film of the present invention, it is preferably a cohesive failure type, and the seal strength is 0 at 25 ° C. from the viewpoint of the balance between easy-openability and sealability. It is preferably 8 N / 15 mm width or more, more preferably 1 N / 15 mm width or more, and the upper limit is preferably 5 N / 15 mm width or less, more preferably 3 N / 15 mm width or less.

<Adhesive resin layer>
The film of the present invention can be provided with at least one adhesive resin layer for adhering each layer. The adhesive resin used in the adhesive resin layer is not particularly limited as long as the above-described thermoplastic resin layer, EVOH layer, PA layer, PE layer, PLA layer, etc. can be bonded to the required strength, but the unsaturated carboxylic acid or A polyolefin resin modified with the derivative can be preferably used.

  Examples of the unsaturated carboxylic acid include acrylic acid, methacrylic acid, maleic acid, fumaric acid, crotonic acid, itaconic acid, citraconic acid and the like. In addition, an ester or anhydride of the unsaturated carboxylic acid can be used as an adhesive resin, and as derivatives, methyl acrylate, methyl methacrylate, ethyl acrylate, propyl acrylate, butyl acrylate, butyl methacrylate, vinyl acetate. , Glycidyl acrylate, glycidyl methacrylate, acrylamide, methacrylamide, sodium acrylate and the like can be used. In particular, when a thermoplastic resin layer, a PE layer, an EVOH layer, and a PLA layer are bonded, a special polyolefin base (polyolefin resin modified with the above unsaturated carboxylic acid or the like) is useful. And when bonding PE layer, the thing of LLDPE type can be used conveniently.

  Specific examples of the adhesive resin preferably used as the adhesive resin layer include, for example, “Admer (registered trademark)” (manufactured by Mitsui Chemicals, Inc.) as a polyolefin-based resin. It can be used suitably.

  It is preferable to provide at least one adhesive resin layer between the outer layer and the intermediate layer. Furthermore, from the viewpoint of further increasing the interlayer adhesive strength, it is provided between the PLA layer and the layer in contact with the PLA layer, between the EVOH layer and the EVA layer or PE layer, or between the PA layer and the EVOH layer. Is preferred. The thickness of the adhesive resin layer is not particularly limited, but in order to maintain an appropriate adhesive strength, it is 2 μm or more, preferably 3 μm or more, more preferably 5 μm or more, 30 μm or less, preferably 20 μm or less, more preferably It is desirable to provide a thickness in the range of 15.

<Layer structure of film for deep drawing>
The film of the present invention is not particularly limited in the order of the layer structure as long as at least one thermoplastic resin layer as an outer layer, at least one PLA layer and PA layer as an intermediate layer, and a heat-sealable resin layer as an inner layer are arranged. Although there is no thermoplastic resin layer A, PLA layer B layer, PA layer C layer, EVOH layer E layer, PE layer F layer, heat sealable resin layer G layer, adhesive resin layer H layer When expressed, the following layer configurations (1) to (8) can be exemplified. Among them, preferred layer structures are (1), (3), and (5), and more preferred layer structures are (1) or (3).
(1) A / H / B / H / C / E / H / F / G
(2) A / H / B / H / E / C / H / F / G
(3) A / E / H / B / H / E / F / G
(4) A / C / H / B / H / E / F / G
(5) A / H / C / E / H / B / H / F / G
(6) A / H / E / C / H / B / H / F / G
(7) A / B / H / C / E / H / F / G
(8) A / B / H / C / E / H / F

More specifically, the following layer structure is also preferable.
(1) PA / EVOH / AD / PLA / AD / PE / EP
(2) EVOH / PA / AD / PLA / AD / PE / EP
(3) PETG / AD / PLA / AD / PA / EVOH / AD / PE / EP
(4) PE / AD / PLA / AD / PA / EVOH / AD / PE / EP

  Here, “/” indicates that the layers described before and after the composite film of the present invention are bonded.

  Each of the above layers may contain other resins and additives in addition to the resin composition constituting each layer as long as the heat sealing property, interlayer strength, and appearance are not impaired. For example, additives such as a heat resistance stabilizer, an oxidation resistance stabilizer, a weather resistance stabilizer, an ultraviolet absorber, a pigment, and a dye may be included as appropriate.

<Method for producing film for deep drawing>
There is no restriction | limiting in particular in the manufacturing method of the film of this invention, It can produce by laminating | stacking an outermost layer, an intermediate | middle layer, and an innermost layer simultaneously or sequentially. Specifically, a film having each layer can be produced at a time by co-extrusion using an extruder equipped with a die using an existing method such as a T-die method or a tubular method. Alternatively, the resin constituting each layer can be made into a sheet separately, and then laminated by using a dry laminating method, a pressing method, an extrusion laminating method, or the like, and sequentially produced.

[Deep-drawing packaging base and deep-drawing packaging]
The film of the present invention can be formed into a deep-drawn packaging body having a size and shape corresponding to the contents using a deep-drawing packaging machine. In particular, when the film of the present invention is used as a bottom material for packaging, a deep-drawn package with excellent gloss can be obtained. Further, the deep-drawn package of the present invention can be produced by bonding the bottom material and the lid material by an adhesive means such as heat sealing.

  Specifically, for example, after the film of the present invention is formed into a desired shape and size with a deep drawing mold to form a bottom material (film supply process and film forming process), contents such as slice ham are contained therein. Fill the product (content filling process), seal with a lid material film (cover material film supply process and sealing process) from above, vacuum package (vacuum packaging process), cool (cooling process), cut By doing (cutting process), a deep drawing package can be produced.

  Examples of the film used as the lid of the deep drawn package of the present invention include a laminate of a stretched polypropylene resin layer, a transparent vapor-deposited polyethylene terephthalate resin and a linear low density polyethylene (LLDPE) layer, and stretched polyethylene. Examples include a laminate of a terephthalate resin and a coextruded film (a film containing EVOH and Ny and having LLDPE as a seal layer).

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples. However, the present invention is not limited to the following examples unless the gist of the present invention is exceeded.

<Preparation of film for deep drawing>
As Examples 1 to 4 and Comparative Example 1, films for deep-drawing packaging having the following configurations and thicknesses were produced by a coextrusion method. In addition, resin used as each layer in an Example and a comparative example is as follows.

Outer layer (thermoplastic resin layer)
Polyethylene resin = Nippon Polyethylene Novatec (LDPE, LLDPE, HDPE, EVA, EEA),
Polypropylene resin = Novatec PP manufactured by Nippon Polypolopylene Co., Ltd.
Polyamide resin = Novamid (6-NY, 6-66 copolymer nylon (66 nylon content 15%), manufactured by Mitsubishi Engineering Plastics Co., Ltd.)
Polyester resin = Eastman Chemical Co., Ltd. PETG6763
Ethylene-vinyl acetate copolymer saponification layer = Kuraray Eval (ethylene content 38 mol% type)
Polylactic acid resin layer “NATURE WORKS (registered trademark)” (manufactured by Nature Works LLC)
Adhesive resin layer “Admer (registered trademark) NF500” (manufactured by Mitsui Chemicals, Inc.),
Polyamide resin layer “NOVAMID (registered trademark)” (6-66 copolymer nylon (66 nylon content 15%)) (Mitsubishi Engineering Plastics Co., Ltd.)
EVOH layer "EVAL (registered trademark)" (ethylene content 38 mol% type) (manufactured by Kuraray Co., Ltd.)
Heat-sealable resin layer Heat-sealable resin layer A: EVA + PB-1 blended product Mitsubishi Chemical Corporation Novatec (registered trademark) EVA + Sun Allomer Co., Ltd. Basel polybutene (PB-1) blended at 60:40 Heat-sealable resin layer B: EVA + PB-1 blend product (3 μm) / LLDPE (2 μm) two-layer structure (the innermost layer is LLDPE)
EVA layer "NOVATEC (registered trademark) EVA" (manufactured by Nippon Polyethylene Co., Ltd.))
Polyethylene resin layer “Novatec (registered trademark) LLDPE” (manufactured by Nippon Polyethylene Co., Ltd.)
PETG layer “PETG6763” (Eastman Chemical Co., Ltd.)

(Example 1)
PETG layer (5 μm) / adhesive resin layer (5 μm) / polylactic acid resin layer (30 μm) / adhesive resin layer (5 μm) / polyamide resin layer (8 μm) / EVOH layer (8 μm) / adhesive resin layer (6 μm) / EVA Layer (26 μm) / heat-sealable resin layer A (7 μm) [total thickness 100 μm]

(Example 2)
Polyamide resin layer (10 μm) / EVOH layer (8 μm) / Adhesive resin layer (5 μm) / Polylactic acid resin layer (30 μm) / Adhesive resin layer (5 μm) / EVA layer (35 μm) / Heat sealable resin layer A (7 μm) ) [Total thickness 100μm]

(Example 3)
EVOH layer (8 μm) / polyamide resin layer (10 μm) / adhesive resin layer (5 μm) / polylactic acid resin layer (30 μm) / adhesive resin layer (5 μm) / EVA layer (37 μm) / heat-sealable resin layer B (5 μm) ) [Total thickness 100μm]

Example 4
PE layer (5 μm) / adhesive resin layer (5 μm) / polylactic acid resin layer (30 μm) / adhesive resin layer (5 μm) / polyamide resin layer (8 μm) / EVOH layer (8 μm) / adhesive resin layer (6 μm) / EVA Layer (26 μm) / heat-sealable resin layer A (7 μm) [total thickness 100 μm]

(Comparative Example 1)
Polylactic acid resin layer (30 μm) / Adhesive resin layer (6 μm) / Polyamide resin layer (10 μm) / EVOH layer (10 μm) / Adhesive resin layer (7 μm) / EVA layer (30 μm) / Heat sealable resin layer A (7 μm) ), [Total thickness 100μm]

<Preparation of pack sample>
Slice ham (50 g) was vacuum-packaged by a deep-drawing packaging machine (FV6300 manufactured by Omori Machine Industry Co., Ltd.) using the deep-drawing film produced in the above Examples and Comparative Examples. In addition, the used lid | cover material laminated | stacks each layer with the following structure by the dry lamination method.
OPP (30 μm) // Transparent deposition PET (12 μm) // LLDPE (40 μm)
OPP (biaxially oriented polypropylene film): “OP U-1” (manufactured by Tosero Co., Ltd.)
Transparent vapor-deposited PET: VM-PET (manufactured by Toyo Metallizing Co., Ltd.)
LLDPE: L-6102 (manufactured by Toyobo Co., Ltd.)

<Evaluation of pack sample>
About the pack sample produced using the film for deep drawing packaging of Examples 1-4 and the comparative example 1, seal | sticker tray property, a moldability (corner, cutability), and the pack sample (curl aptitude, rigidity of a flange part) were evaluated. . The evaluation method is as follows. The results are shown in Table 1.

<Seal packing tolerance>
The seal packing tray of the bottom product of the pack was evaluated. Evaluation was made in four grades: ◎> ○ with good gloss without sealing and ×, and x with 底>○>Δ> × where the outer layer side of the bottom material was glazed due to packing heat.

<Pack sample (curl suitability, flange rigidity)>
(Curlability of flange part)
The curl of the flange portion of the pack product was evaluated. A flat thing without curling was evaluated as ◎, and a thing curled toward the bottom material side or the lid material side was evaluated as ×, and evaluation was performed in four stages: ◎>○>Δ> ×.
(Label suitability)
In the sticking of the adhesive label, ◎ indicates that the adhesive property is good, and × indicates that the adhesive property is bad.
(Rigidity of formable flange)
The evaluation was made in four stages: ◎>○>△> ×, where ◎ indicates that the corner is difficult to collapse and has a rigid feeling, and X indicates that the corner is easy to collapse and does not have a rigid feeling.

  From Table 1, the deep-drawn packages of Examples 1 to 4 of the present invention did not have practically unusable (x) items in all evaluation items, and showed good evaluation results. In particular, with seal packing trays, good results are obtained without losing the appearance, and the evaluation of the moldability, flange curl suitability, molding corner mold determinism, and deep draw packaging machine cutability are the same as those of the conventional products. Compared with Comparative Example 1, the deep drawn package of the present invention was greatly improved in appearance as compared with the conventional product, and the set seal temperature range was expanded.

  Although the present invention has been described with reference to the most practical and preferred embodiments at the present time, the present invention is not limited to the embodiments disclosed herein. However, it can be changed as appropriate without departing from the spirit or concept of the invention that can be read from the claims and the entire specification, and a film for deep drawing, a bottom material for deep drawing packaging, and a deep drawing with such changes Packaging must also be understood as being within the scope of the present invention.

Claims (8)

A deep drawing characterized by having at least one thermoplastic resin layer as an outer layer, at least one polylactic acid (PLA) resin layer and polyamide resin (PA) layer as an intermediate layer, and a heat-sealable resin layer as an inner layer Film for molding. The deep drawing film according to claim 1, further comprising at least one ethylene-vinyl acetate copolymer saponified product (EVOH) layer as the intermediate layer. The deep drawing film according to claim 1 or 2, further comprising at least one ethylene-vinyl acetate copolymer (EVA) layer or polyethylene (PE) layer as the intermediate layer. The deep drawing film according to any one of claims 1 to 3, further comprising at least one adhesive resin layer as the intermediate layer. Any of Claims 1-4 in which the said heat-sealable resin layer is comprised with either the resin composition A shown below, the resin composition B, and the mixture of the resin composition A and the resin composition B. The deep drawing film according to claim 1.
Resin composition A: Main component is linear low density polyethylene (LLDPE), ethylene-vinyl acetate copolymer (EVA), ethylene-acrylic acid copolymer (EAA), ethylene-ethyl acrylate copolymer (EEA) ), Ethylene-methacrylic acid copolymer (EMAA), ethylene-methyl methacrylate copolymer (EMMA), ethylene-methyl acrylate copolymer (EMA), ethylene-acrylic acid copolymer (EAA) and ethylene -Resin composition selected from the group consisting of ionomers of ethyl acrylate copolymer (EEA) or a mixture thereof Resin composition B: resin whose main component is polypropylene (PP) or polybutene-1 (PB-1) Composition or mixture thereof The deep drawing film according to any one of claims 1 to 5, wherein the heat-sealable resin layer has a seal strength of 0.8 N / 15 mm width or more and 40 N / 15 mm width or less at 25 ° C. A bottom material for a deep-drawn packaging body, which is formed by the deep-drawing film according to any one of claims 1 to 6. A deep drawn package using the bottom material for a deep drawn package according to claim 7.