WO2013121874A1 - Film multicouche thermorétractable - Google Patents

Film multicouche thermorétractable Download PDF

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Publication number
WO2013121874A1
WO2013121874A1 PCT/JP2013/051849 JP2013051849W WO2013121874A1 WO 2013121874 A1 WO2013121874 A1 WO 2013121874A1 JP 2013051849 W JP2013051849 W JP 2013051849W WO 2013121874 A1 WO2013121874 A1 WO 2013121874A1
Authority
WO
WIPO (PCT)
Prior art keywords
layer
heat
seal
multilayer film
gas barrier
Prior art date
Application number
PCT/JP2013/051849
Other languages
English (en)
Japanese (ja)
Inventor
隆久 上山
忠良 伊藤
伊藤　大輔
裕太 関谷
Original Assignee
株式会社クレハ
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 株式会社クレハ filed Critical 株式会社クレハ
Priority to JP2014500158A priority Critical patent/JP6054364B2/ja
Publication of WO2013121874A1 publication Critical patent/WO2013121874A1/fr

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/32—Layered products comprising a layer of synthetic resin comprising polyolefins
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/06—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material
    • B32B27/08—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/30—Layered products comprising a layer of synthetic resin comprising vinyl (co)polymers; comprising acrylic (co)polymers
    • B32B27/304—Layered products comprising a layer of synthetic resin comprising vinyl (co)polymers; comprising acrylic (co)polymers comprising vinyl halide (co)polymers, e.g. PVC, PVDC, PVF, PVDF
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/30—Layered products comprising a layer of synthetic resin comprising vinyl (co)polymers; comprising acrylic (co)polymers
    • B32B27/306—Layered products comprising a layer of synthetic resin comprising vinyl (co)polymers; comprising acrylic (co)polymers comprising vinyl acetate or vinyl alcohol (co)polymers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
    • B32B7/02—Physical, chemical or physicochemical properties
    • B32B7/027—Thermal properties
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
    • B65D65/00—Wrappers or flexible covers; Packaging materials of special type or form
    • B65D65/38—Packaging materials of special type or form
    • B65D65/40—Applications of laminates for particular packaging purposes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
    • B65D75/00—Packages comprising articles or materials partially or wholly enclosed in strips, sheets, blanks, tubes, or webs of flexible sheet material, e.g. in folded wrappers
    • B65D75/002—Packages comprising articles or materials partially or wholly enclosed in strips, sheets, blanks, tubes, or webs of flexible sheet material, e.g. in folded wrappers in shrink films
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2250/00—Layers arrangement
    • B32B2250/24—All layers being polymeric
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2307/00—Properties of the layers or laminate
    • B32B2307/30—Properties of the layers or laminate having particular thermal properties
    • B32B2307/31—Heat sealable
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2307/00—Properties of the layers or laminate
    • B32B2307/70—Other properties
    • B32B2307/724—Permeability to gases, adsorption
    • B32B2307/7242—Non-permeable
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2439/00—Containers; Receptacles
    • B32B2439/70—Food packaging

Definitions

  • the present invention relates to a heat-shrinkable multilayer film that enables efficient packaging of raw meat, processed meat, and the like.
  • a film used for shrink wrapping is formed of a multilayer having at least a surface layer forming an outer surface, a gas barrier layer having gas barrier properties, and a seal layer forming an inner surface, and has a good appearance and freshness depending on the properties of each layer.
  • heat shrinkability, transparency, gas barrier property, or heat sealability is imparted.
  • shrink film having gas barrier properties examples include polypropylene or a polypropylene-based copolymer as a surface layer, ethylene vinyl alcohol copolymer (EVOH) or nylon 6,12 copolymer or nylon 6,66 copolymer as a gas barrier layer, and ethylene as a sealing layer.
  • EVOH ethylene vinyl alcohol copolymer
  • nylon 6,12 copolymer or nylon 6,66 copolymer as a gas barrier layer
  • ethylene as a sealing layer.
  • a film in which an ⁇ -olefin copolymer is laminated is disclosed (see, for example, Patent Documents 1 to 3).
  • Overlap sealability means that when a packaging bag is formed with a multilayer film with the sealing layer facing inward, and the packaging bags are stacked and heat sealed, the sealing layers of each packaging bag are heat-sealed, and the surface It refers to the property that the layers are not heat-sealed or heat-sealed only to such an extent that they can be peeled off.
  • heat sealing can be performed in a state where a part of the packaging bag is overlapped. Therefore, the number of packaging bags that can be heat sealed at a time can be increased, and the operation becomes efficient. Moreover, it becomes unnecessary to arrange so that packaging bags may not overlap, and workability
  • a film having a lap seal property is disclosed by crosslinking a surface layer forming an outer surface and uncrosslinking a seal layer forming an inner surface.
  • the outer surface is made of a resin having a relatively high melting temperature such as a polyamide resin or a polyester resin
  • the inner surface is formed of a resin having a relatively low melting temperature such as a polyolefin resin.
  • a film provided with an overlap seal by providing a temperature difference see, for example, Patent Documents 5 to 8).
  • the excess portion of the film after shrinkage of the bag or pouch (hereinafter referred to as the “ear part”) is poor in appearance. I can't go wrong.
  • the fact that the sealing layers of the bag or pouch ears are fused by heat treatment does not stand out the gravy (hereinafter referred to as drip) generated from raw or processed meat after packaging. That is why it is preferred by consumers.
  • the self-weld property is inferior, that is, when there is no fusion of the ears after heat treatment, or when there is almost no fusion, the drip accumulates in the ears during storage after packaging, and the appearance becomes poor.
  • the heat treatment here refers to heat treatment such as heat shrinkage, heat sterilization, and cooking at a specific temperature.
  • a packaging laminate having self-weld properties is disclosed (see, for example, Patent Document 9).
  • JP 2007-152570 A Japanese Patent Laid-Open No. 10-80984 JP-A-10-29283 Japanese Patent Laid-Open No. 9-39179 International Publication No. 2008/099799 European Patent No. 1131205 European Patent Application Publication No. 1985443 European Patent Application Publication No. 2147783 International Publication No. 2000/47406
  • the temperature range in which the inner surfaces can be heat-sealed without heat-sealing the outer surfaces is narrow, and the overlap sealability is insufficient.
  • resins having a high melting temperature such as polyamide resin and polyester resin must naturally have a high extrusion temperature.
  • PVDC polyvinylidene chloride resin
  • the processing temperature cannot be increased considering the decomposition of PVDC.
  • the die temperature cannot be increased, and a resin having a high melting temperature such as a polyamide resin or a polyester resin cannot be stably extruded. Therefore, the smoothness of the film surface may be deteriorated and appearance defects may occur.
  • An object of the present invention is to provide a heat-shrinkable multilayer film which is excellent in lap sealability and self-weld property and has heat shrinkability, gas barrier properties and heat sealability.
  • the heat-shrinkable multilayer film according to the present invention has a multilayer structure having a surface layer, an intermediate layer T1, a gas barrier layer, and a seal layer, and the multilayer structure has the surface layer disposed on one surface, And in the heat-shrinkable multilayer film formed by arranging the seal layer on the other surface, the surface layer contains a propylene-ethylene copolymer, and the gas barrier layer contains a polyvinylidene chloride resin.
  • the difference in melting temperature between the surface layer and the sealing layer is 35 to 60 ° C.
  • the multilayer structure preferably further includes an intermediate layer T2 between the gas barrier layer and the seal layer. It works as a reinforcing layer of the seal layer and can improve the seal strength. Moreover, stretchability can be improved.
  • the seal layer contains at least one of an ionomer and an ethylene-vinyl acetate copolymer. It can be set as the film excellent in extending
  • the heat-shrinkable multilayer film according to the present invention preferably has a self-weld property by heat treatment. Appearance after vacuum packaging can be improved.
  • the present invention can provide a heat-shrinkable multilayer film that is excellent in lap sealability and self-weld property and has heat shrinkability, gas barrier properties, and heat sealability.
  • the heat-shrinkable multilayer film according to this embodiment includes a multilayer structure having a surface layer, an intermediate layer T1, a gas barrier layer, and a seal layer, and the multilayer structure has the surface layer disposed on one surface.
  • the surface layer contains a propylene-ethylene copolymer
  • the gas barrier layer is a polyvinylidene chloride resin.
  • the difference in melting temperature between the surface layer and the sealing layer is 35 to 60 ° C.
  • the surface layer is a layer that is disposed on one surface of the multilayer structure and becomes the outer surface of the bag, and has a role of imparting heat resistance and gloss.
  • the surface layer contains a propylene-ethylene copolymer.
  • the propylene-ethylene copolymer include a propylene-ethylene random copolymer, a propylene-ethylene block copolymer, and a propylene-ethylene-butene terpolymer. These may be used alone or in combination of two or more. Among these, a propylene-ethylene random copolymer is particularly preferable from the viewpoints of stretchability and transparency.
  • the propylene-ethylene copolymer is preferably a copolymer of 60 to 99.9% by mass of propylene and 0.1 to 40% by mass of another monomer (comonomer). More preferably, the proportion of propylene in the propylene-ethylene copolymer is 75 to 99.5% by mass.
  • the density of the resin used for the surface layer is preferably 0.880 g / cm 3 or more and 0.940 g / cm 3 or less. More preferably, it is 0.890 g / cm 3 or more and 0.925 g / cm 3 or less.
  • the melt flow rate (MFR) (230 ° C., 2.16 kg) of the resin used for the surface layer is preferably 1.0 g / 10 min or more and 25 g / 10 min or less. More preferably, it is 2.0 g / 10 min or more and 20 g / 10 min.
  • the melting temperature of the resin used for the surface layer is preferably 130 ° C. or higher and 170 ° C. or lower. More preferably, it is 135 degreeC or more and 160 degrees C or less. Especially preferably, it is 140 degreeC or more and 155 degrees C or less. If it is less than 130 ° C., the heat resistance is insufficient, and the surface layer may melt during thermal processing such as sealing. If it exceeds 170 ° C., the extrusion processing temperature becomes high, so that the PVDC in the gas barrier layer may be decomposed. Moreover, the smoothness of the surface may be inferior or the stretchability may be hindered.
  • the surface layer may contain various additives such as a crystal nucleating agent, a lubricant, an antistatic agent, a softening agent, a heat stabilizer, a plasticizer, and an antioxidant.
  • Crystal nucleating agents improve transparency, heat resistance, moldability, and the like.
  • sorbitol compounds such as dibenzylidene sorbitol; organophosphate compounds; rosinate compounds; Aliphatic dicarboxylic acid or metal salt thereof; aromatic carboxylic acid or metal salt thereof.
  • the lubricant reduces the boundary friction between the film and the machine surface of the bag making machine or the packaging machine.
  • hydrocarbon lubricants such as liquid paraffin and polyethylene wax
  • aliphatic systems such as stearic acid and lauric acid Lubricants
  • aliphatic amide-based lubricants such as stearamide and erucamide
  • ester-based lubricants such as ethylene glycol monostearate and monoglyceride stearate
  • metal soaps such as zinc stearate and calcium stearate.
  • fatty acid amide lubricants and metal soaps are preferably used from the viewpoint of excellent compatibility with polyolefin resins.
  • Antistatic agents cause static electricity damage, such as the product sticking to rolls due to static electricity, reducing the mechanical suitability of bags, etc., and the product sticking to each other, reducing the workability when taking out one product at a time.
  • an anionic surfactant such as ethylene- ⁇ olefin copolymer and propylene- ⁇ olefin copolymer; ethylene-vinyl acetate copolymer, etc.
  • the thickness of the surface layer is preferably 0.5 ⁇ m or more and 40 ⁇ m or less. More preferably, they are 1 micrometer or more and 10 micrometers or less.
  • ⁇ Powder can be applied to the surface of the surface layer.
  • the powder has a role of expanding the temperature range in which the layers can be sealed.
  • the powder is, for example, starch.
  • the average particle size of the powder is preferably 5 to 50 ⁇ m. Further, a plurality of kinds of powders having different particle sizes may be blended to have a distribution in the average particle size.
  • the mid layer T1 preferably contains a polyolefin resin.
  • the polyolefin resin include low density polyethylene (LDPE); medium density polyethylene (MDPE); polypropylene (PP); a copolymer of propylene and an ⁇ -olefin having 2 or 4 to 8 carbon atoms; an ethylene- ⁇ -olefin copolymer.
  • Polymer ethylene-vinyl acetate copolymer (EVA), ethylene-alkyl acrylate having 1 to 4 carbon atoms, ethylene-methacrylic acid copolymer, ethylene-methacrylic acid-unsaturated carboxylic acid copolymer, etc.
  • the ethylene- ⁇ olefin copolymer includes a copolymer obtained using a Ziegler-Natta catalyst and a copolymer obtained using a metallocene catalyst.
  • the ⁇ -olefin as a comonomer used for the polymerization of the ethylene- ⁇ -olefin copolymer is, for example, butene-1, having 4 carbon atoms, pentene-1, 5 carbon atoms, 4-methylpentene-1 having 6 carbon atoms, or Hexene-1 or octene-1 having 8 carbon atoms.
  • the density is 0.900g / cm 3 ⁇ 0.909g / cm 3 very low density polyethylene (VLDPE), density of 0.910g / cm 3 ⁇ 0.925g It is a linear low density polyethylene (LLDPE) that is / cm 3 .
  • VLDPE very low density polyethylene
  • LLDPE linear low density polyethylene
  • EVA ethylene-alkyl acrylate having 1 to 4 carbon atoms
  • ethylene-methacrylic acid copolymer ethylene-methacrylic acid-unsaturated carboxylic acid in terms of stretchability, adhesion to the surface layer and transparency.
  • Particularly preferred are ethylene-polar comonomer copolymers such as acid copolymers; ionomers.
  • the resins used for the intermediate layer T1 may be used alone or in combination of two or more.
  • the intermediate layer T1 may contain various additives such as a lubricant, an antistatic agent, a heat stabilizer, a plasticizer, an antioxidant, and a softening agent. In this, it is more preferable to contain a softening agent at the point which can suppress the bending phenomenon of the film at the time of shrinkage
  • softener examples include polyolefin elastomers such as ethylene- ⁇ olefin copolymers and propylene- ⁇ olefin copolymers; ethylene copolymers such as ethylene-vinyl acetate copolymers; polyisobutylenes; polybutenes; polybutadienes; Butadiene-styrene copolymer; neoprene; natural rubber.
  • polyolefin elastomers such as ethylene- ⁇ olefin copolymers and propylene- ⁇ olefin copolymers
  • ethylene copolymers such as ethylene-vinyl acetate copolymers
  • polyisobutylenes polybutenes
  • polybutadienes butadiene-styrene copolymer
  • Butadiene-styrene copolymer butadiene-styrene copolymer
  • neoprene natural
  • the melting temperature of the resin used for the intermediate layer T1 is not particularly limited, but is preferably 70 ° C. or higher and 120 ° C. or lower. More preferably, it is 80 degreeC or more and 100 degrees C or less.
  • Density of the resin used for the intermediate layer T1 is preferably less 0.880 g / cm 3 or more 0.960 g / cm 3. More preferably, the 0.900 g / cm 3 or more 0.940 g / cm 3 or less.
  • the MFR (190 ° C., 2.16 kg) of the resin used for the intermediate layer T1 is preferably 0.5 g / 10 min or more and 20 g / 10 min or less. More preferably, it is 1.0 g / 10 min or more and 15 g / 10 min or less.
  • the thickness of the intermediate layer T1 is preferably 5 ⁇ m or more and 50 ⁇ m or less. More preferably, they are 10 micrometers or more and 40 micrometers or less.
  • the intermediate layer T1 may be formed of one layer or two or more layers. When the intermediate layer T1 is formed of two or more layers, the layers may have the same composition, or the layers may have different compositions.
  • An adhesive layer S1 may be further provided between the intermediate layer T1 and the gas barrier layer.
  • the adhesive layer S1 is a layer adjacent to the gas barrier layer, and has a role of improving adhesion to the gas barrier layer.
  • the adhesive layer S1 preferably contains an adhesive resin such as an ethylene-polar comonomer copolymer or an acid-modified polyolefin.
  • ethylene-polar comonomer copolymers include ethylene-vinyl acetate copolymers, ethylene-alkyl acrylates having 1 to 4 carbon atoms, ethylene-methacrylic acid copolymers, and ethylene-methacrylic acid-unsaturated carboxylic acid copolymers.
  • the acid-modified polyolefin is, for example, a reaction product of an olefin homo- or copolymer and an unsaturated carboxylic acid such as maleic acid or fumaric acid, an acid anhydride, an ester, or a metal salt.
  • the resins used for the adhesive layer S1 may be used alone or in combination of two or more.
  • adhesive layer S1 may contain various additives, such as a heat stabilizer, a plasticizer, and antioxidant other than adhesive resin.
  • the melting temperature of the resin used for the adhesive layer S1 is not particularly limited, but is preferably 70 ° C or higher and 130 ° C or lower. More preferably, it is 80 degreeC or more and 120 degrees C or less.
  • Density of the resin used in the adhesive layer S1 is preferably not more than 0.880 g / cm 3 or more 0.960 g / cm 3. More preferably, the 0.900 g / cm 3 or more 0.940 g / cm 3 or less.
  • the MFR (190 ° C., 2.16 kg) of the resin used for the adhesive layer S1 is preferably 0.5 g / 10 min or more and 20 g / 10 min or less. More preferably, it is 1.0 g / 10 min or more and 15 g / 10 min or less.
  • the thickness of the adhesive layer S1 is preferably 0.5 ⁇ m or more and 10 ⁇ m or less. More preferably, they are 1 micrometer or more and 5 micrometers or less.
  • the gas barrier layer has a role of preventing deterioration of contents by suppressing permeation of oxygen, water vapor and the like.
  • the gas barrier layer contains a polyvinylidene chloride (PVDC) resin as a gas barrier resin.
  • PVDC polyvinylidene chloride
  • the polyvinylidene chloride resin is, for example, a copolymer of 2 to 40% by mass of another monomer (comonomer) copolymerizable with 60 to 98% by mass of vinylidene chloride (VDC).
  • VDC vinylidene chloride
  • Examples of the comonomer include vinyl chloride; alkyl acrylate esters such as methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, stearyl acrylate (alkyl group having 1 to 18 carbon atoms).
  • Alkyl methacrylates such as methyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, stearyl methacrylate (alkyl group having 1 to 18 carbon atoms); vinyl cyanide such as acrylonitrile and methacrylonitrile; Aromatic vinyl such as styrene; vinyl ester of aliphatic carboxylic acid having 1 to 18 carbon atoms such as vinyl acetate; alkyl vinyl ether having 1 to 18 carbon atoms; acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, etc.
  • Vinyl polymerizable unsaturated carboxylic acids alkyl esters of vinyl polymerizable unsaturated carboxylic acids such as maleic acid, fumaric acid and itaconic acid (including partial esters, having 1 to 18 carbon atoms in the alkyl group); Body, functional group-containing monomer, polyfunctional monomer and the like.
  • comonomers can be used alone or in combination of two or more.
  • vinyl chloride, methyl acrylate or lauryl acrylate is preferable.
  • the copolymerization ratio of the comonomer is preferably 3 to 35% by mass, more preferably 10 to 25% by mass.
  • the reduced viscosity ( ⁇ sp / C) of the polyvinylidene chloride-based resin is preferably 0.035 to 0.070, more preferably from the viewpoint of processability when molded into a film, suitability for packaging machinery, cold resistance, and the like. It is 0.040 to 0.065, and particularly preferably 0.045 to 0.063. If the reduced viscosity of the polyvinylidene chloride-based resin is too low, the processability is deteriorated, and if it is too high, a tendency toward coloring is exhibited, so neither is preferred. Two or more types of polyvinylidene chloride resins having different reduced viscosities can be used in combination, thereby improving workability. When two or more kinds of polyvinylidene chloride resins are used in combination, the reduced viscosity of the mixed resin is preferably within the above range.
  • the polyvinylidene chloride resin can be blended with other resins as desired.
  • Other resins include, for example, ethylene-vinyl acetate copolymer, (meth) acrylic acid ester, preferably (co) polymer of alkyl group (meth) acrylic acid alkyl ester having 1 to 18 carbon atoms [for example, (Methyl (meth) acrylate- (meth) butyl acrylate copolymer), methyl methacrylate-butadiene-styrene copolymer, and the like.
  • These other resins can be blended when preparing the polyvinylidene chloride resin composition, or can be contained in the coloring resin composition blended with the polyvinylidene chloride resin.
  • the other resin is usually used at a ratio of 20 parts by mass or less with respect to 100 parts by mass of the polyvinylidene chloride resin.
  • the gas barrier resins may be used alone or in combination of two or more.
  • the gas barrier resin and the polyolefin-based resin can obtain good adhesiveness by interposing the adhesive layer S1 and the adhesive layer S2 described later.
  • the gas barrier layer may contain various additives such as a heat stabilizer, a plasticizer, and an antioxidant in addition to the gas barrier resin.
  • the thickness of the gas barrier layer is preferably 1 ⁇ m or more and 40 ⁇ m or less. More preferably, they are 3 micrometers or more and 30 micrometers or less, Especially preferably, they are 4 micrometers or more and 10 micrometers or less.
  • the gas barrier layer may be formed of one layer or two or more layers. When two or more gas barrier layers are formed, each layer may have the same composition, or each layer may have a different composition.
  • the sealing layer is disposed on the surface opposite to the surface layer, becomes the inner surface of the bag, and has a role of sealing the bag by heat sealing.
  • the sealing layer preferably contains a polyolefin resin.
  • polyolefin resins include low-density polyethylene (LDPE); ethylene- ⁇ olefin copolymer; ethylene-vinyl acetate copolymer (EVA), ethylene-alkyl acrylate having 1 to 4 carbon atoms, and ethylene-methacrylic acid copolymer.
  • LDPE low-density polyethylene
  • EVA ethylene-vinyl acetate copolymer
  • the ethylene- ⁇ olefin copolymer includes a copolymer obtained using a Ziegler-Natta catalyst and a copolymer obtained using a metallocene catalyst.
  • the ⁇ -olefin as a comonomer used for the polymerization of the ethylene- ⁇ -olefin copolymer is, for example, butene-1, having 4 carbon atoms, pentene-1, 5 carbon atoms, 4-methylpentene-1 having 6 carbon atoms, or Hexene-1 or octene-1 having 8 carbon atoms.
  • the density is 0.900 g / cm 3 or more 0.909 g / cm 3 or less very low density polyethylene (VLDPE), density of 0.910 g / cm 3 or more zero. It is a linear low density polyethylene (LLDPE) that is 925 g / cm 3 or less.
  • VLDPE very low density polyethylene
  • an ionomer uses, as a base polymer, an ethylene-unsaturated carboxylic acid copolymer or an ethylene-ethylenically unsaturated carboxylic acid-ethylenically unsaturated carboxylic acid ester terpolymer, and carboxyls in these copolymers.
  • the unsaturated carboxylic acid is preferably, for example, methacrylic acid or acrylic acid.
  • the copolymerization ratio of unsaturated carboxylic acid is preferably 3 to 20% by mass. More preferably, it is 5 to 15% by mass, and particularly preferably 7 to 13% by mass. When the copolymerization ratio of the unsaturated carboxylic acid is too large, the sealing strength tends to decrease.
  • the unsaturated carboxylic acid ester is preferably an alkyl ester of (meth) acrylic acid having 1 to 6 carbon atoms.
  • the copolymerization ratio of the unsaturated carboxylic acid ester is preferably 3 to 30% by mass.
  • the copolymerization ratio of the unsaturated carboxylic acid ester is 4 to 15% by mass, and particularly preferably 5 to 10% by mass. If the copolymerization ratio of the unsaturated carboxylic acid ester is too large, the bag-making property tends to deteriorate due to excessive flexibility and stickiness, and the sealing strength tends to decrease.
  • the cation used for neutralization include Na + , K + , Li + , Cs + , Ag + , Hg + , Cu + , Mg 2+ , Zn 2+ , Be 2+ , Ca 2+ , Ba 2+ and Cu 2+.
  • the ratio of the metal or organic amine content in the resin to the acid content in the resin is preferably 1 to 15%. More preferably, it is 3 to 15%. If it exceeds 15%, there may be a case where a practically required level of sealing strength cannot be obtained.
  • An ionomer having a neutralization degree of 15% or less may be prepared by blending two or more ionomers having different ionization degrees.
  • the ionomer can be used by blending with, for example, an ethylene-methacrylic acid copolymer, an ethylene-methacrylic acid-acrylic acid ester terpolymer, etc.
  • the blend ratio of the ionomer is 50% by mass or more. Preferably there is.
  • EVA and ionomer are particularly preferable in terms of stretchability, low temperature sealability and self-weldability.
  • the vinyl acetate content of EVA is preferably 5 to 30% by mass.
  • the resins used for the seal layer may be used alone or in combination of two or more.
  • the seal layer may contain various additives such as a heat stabilizer, a plasticizer, and an antioxidant in addition to the polyolefin resin.
  • the density of the resin used for the seal layer is preferably 0.880 g / cm 3 or more and 0.940 g / cm 3 or less. More preferably, the 0.900 g / cm 3 or more 0.925 g / cm 3 or less.
  • the MFR (190 ° C., 2.16 kg) of the resin used for the seal layer is preferably 0.5 g / 10 min or more and 20 g / 10 min or less. More preferably, it is 1.0 g / 10 min or more and 15 g / 10 min or less.
  • the melting temperature of the resin used for the seal layer is preferably 80 ° C. or higher and 130 ° C. or lower. More preferably, it is 85 degreeC or more and 100 degrees C or less, Most preferably, it is 85 degreeC or more and 95 degrees C or less. If it is less than 80 degreeC, blocking generate
  • the melting temperature of resin used for a sealing layer is 80 degreeC or more and 100 degrees C or less. More preferably, it is 80 degreeC or more and 95 degrees C or less, Most preferably, it is 85 degreeC or more and 95 degrees C or less.
  • the melting temperature of the seal layer is lower than the melting temperature of the surface layer, and the difference in melting temperature is 35 ° C. or more and 60 ° C. or less. More preferably, it is 40 degreeC or more and 60 degrees C or less, Most preferably, it is 45 degreeC or more and 60 degrees C or less.
  • the difference in melting temperature between the surface layer and the sealing layer is less than 35 ° C., the temperature range in which the overlapping sealing property is exhibited is narrow, and the practicality is lacking.
  • the difference in melting temperature between the surface layer and the seal layer exceeds 60 ° C., the difference in processing temperature increases, and when the melting temperature of the seal layer is relatively high, the melting temperature of the surface layer becomes relatively high.
  • the PVDC of the gas barrier layer may be decomposed or the smoothness of the surface may be inferior.
  • the melting temperature of the surface layer is relatively low, the melting temperature of the seal layer is relatively low. In this case, blocking of the seal layer may occur.
  • the thickness of the seal layer is preferably 3 ⁇ m or more and 50 ⁇ m or less. More preferably, they are 5 micrometers or more and 30 micrometers or less, Especially preferably, they are 8 micrometers or more and 20 micrometers or less.
  • An intermediate layer T2 may be further provided between the gas barrier layer and the seal layer.
  • the intermediate layer T2 functions as a reinforcing layer of the seal layer and has a role of improving the seal strength. Also, it has a role of improving stretchability and shrinkage.
  • the mid layer T2 preferably contains a polyolefin resin.
  • the polyolefin-based resin those exemplified in the intermediate layer T1 can be used, and EVA, ethylene-alkyl acrylate having 1 to 4 carbon atoms, ethylene-methacrylic acid in terms of stretchability, adhesion to the seal layer and transparency.
  • ethylene-polar comonomer copolymers such as ethylene-methacrylic acid-unsaturated carboxylic acid copolymers; ionomers are particularly preferred.
  • the resins used for the intermediate layer T2 may be used alone or in combination of two or more.
  • the intermediate layer T2 may contain various additives such as a heat stabilizer, a plasticizer, and an antioxidant in addition to the polyolefin resin.
  • the melting temperature of the resin used for the intermediate layer T2 is not particularly limited, but is preferably 70 ° C or higher and 120 ° C or lower. More preferably, it is 80 degreeC or more and 100 degrees C or less.
  • Density of the resin used for the intermediate layer T2 is preferably less 0.880 g / cm 3 or more 0.960 g / cm 3. More preferably, the 0.900 g / cm 3 or more 0.940 g / cm 3 or less.
  • the MFR (190 ° C., 2.16 kg) of the resin used for the intermediate layer T2 is preferably 0.5 g / 10 min or more and 20 g / 10 min or less. More preferably, it is 1.0 g / 10 min or more and 15 g / 10 min or less.
  • the thickness of the intermediate layer T2 is preferably 3 ⁇ m or more and 50 ⁇ m or less. More preferably, they are 5 micrometers or more and 30 micrometers or less, Especially preferably, they are 8 micrometers or more and 20 micrometers or less.
  • the intermediate layer T2 may be formed of one layer or two or more layers. When the intermediate layer T2 is formed of two or more layers, the layers may have the same composition, or the layers may have different compositions.
  • An adhesive layer S2 may be further provided between the gas barrier layer and the intermediate layer T2.
  • the adhesive layer S2 is a layer adjacent to the gas barrier layer, and has a role of improving the adhesion to the gas barrier layer.
  • the adhesive resin exemplified in the adhesive layer S1 can be used, and each of them can be used alone or in combination of two or more.
  • the adhesive layer S2 may contain various additives such as a heat stabilizer, a plasticizer, and an antioxidant in addition to the adhesive resin.
  • the melting temperature of the resin used for the adhesive layer S2 is not particularly limited, but is preferably 70 ° C or higher and 130 ° C or lower. More preferably, it is 80 degreeC or more and 120 degrees C or less.
  • Density of the resin used in the adhesive layer S2 is preferably not more than 0.880 g / cm 3 or more 0.960 g / cm 3. More preferably, the 0.900 g / cm 3 or more 0.940 g / cm 3 or less.
  • the MFR (190 ° C., 2.16 kg) of the resin used for the adhesive layer S2 is preferably 0.5 g / 10 min or more and 20 g / 10 min or less. More preferably, it is 1.0 g / 10 min or more and 15 g / 10 min or less.
  • the thickness of the adhesive layer S2 is preferably 0.5 ⁇ m or more and 10 ⁇ m or less. More preferably, they are 1 micrometer or more and 5 micrometers or less.
  • the heat-shrinkable multilayer film according to the present embodiment has a multilayer structure having at least a surface layer, an intermediate layer T1, a gas barrier layer, and a seal layer.
  • the multilayer structure may be formed in various forms depending on the use as long as a surface layer is disposed on one surface and a seal layer is disposed on the other surface. Examples of the multilayer structure include a four-layer structure in which a surface layer, an intermediate layer T1, a gas barrier layer, and a seal layer are sequentially stacked, and five layers in which a surface layer, an intermediate layer T1, a gas barrier layer, an intermediate layer T2, and a seal layer are sequentially stacked.
  • the thickness of the heat-shrinkable multilayer film according to this embodiment is preferably 20 ⁇ m or more and 150 ⁇ m or less. More preferably, they are 30 micrometers or more and 120 micrometers or less, Most preferably, they are 40 micrometers or more and 80 micrometers or less. If it is less than 20 ⁇ m, the mechanical strength may be insufficient. If it exceeds 150 ⁇ m, the time required for heat sealing becomes long, and the packaging suitability may be inferior. Further, the stretch processability may be inferior.
  • the heat-shrinkable multilayer film according to this embodiment preferably has a self-weld property.
  • the self-weld property refers to the property that the sealing layers are fused together by heat at the ear portion after shrinkage of the bag or pouch when heat treatment such as heat shrinkage, heat sterilization, cooking, etc. is performed at a specific temperature.
  • heat treatment such as heat shrinkage, heat sterilization, cooking, etc.
  • heat sterilization may be performed at 95 ° C.
  • contraction is 1 N / 15mm or more.
  • it is 3N / 15mm or more, Most preferably, it is 5N / 15mm or more. If it is less than 1 N / 15 mm, it does not have a substantial self-weld property, and drip accumulates in the ear during storage after packaging, which may deteriorate the appearance.
  • the heat-shrinkable multilayer film according to this embodiment has a hot-water shrinkage rate of at least 30% at 80 ° C. in at least one of the machine direction of the film (MD direction) or the direction perpendicular to the machine direction of the film (TD direction). It is preferable that it is 60% or less. More preferably, it is 35% or more and 55% or less. Particularly preferably, it is 45% or more and 55% or less.
  • the hot water shrinkage rate is less than 30%, the shrinkage amount is insufficient and the appearance of the package may deteriorate. If the hot water shrinkage rate exceeds 60%, the contents may be deformed by excessive shrinkage.
  • the hot water shrinkage ratio is obtained by immersing the difference between the length in the MD direction or the TD direction of the film before being immersed in hot water (80 ° C.) and the length of the film after being immersed in hot water in hot water. It is expressed as a percentage divided by the length in the MD direction or TD direction of the previous film.
  • the heat-shrinkable multilayer film according to this embodiment has a lap seal.
  • the lap sealing property is a multilayer film with a sealing layer facing inward to form a packaging bag, and when the packaging bags are stacked and heat sealed, the sealing layers of each packaging bag are heat-sealed, And the surface layer does not heat-seal or refers to the property of heat-sealable to such an extent that it can be peeled off.
  • the fusion strength between the seal layers (also referred to as seal strength) is preferably 10 N / 15 mm or more. More preferably, it is 15 N / 15 mm or more.
  • the fusion strength between the sealing layers of each packaging bag is less than 10 N / 15 mm, the sealing performance is insufficient, and air may enter the bag during the packaging process or during transportation.
  • the fusion strength between the surface layers is preferably 1.5 N / 15 mm or less, and more preferably 1.0 N / 15 mm or less.
  • the measuring method of seal strength is as having described in the Example.
  • the method for producing a heat-shrinkable multilayer film comprises at least a resin composition for forming a surface layer, a resin composition for forming an intermediate layer T1, a resin composition for forming a gas barrier layer, and a resin composition for forming a seal layer.
  • Each has a lamination step of forming a laminate having a multilayer structure and a stretching step of stretching the laminate.
  • the method for forming a multilayer structure is not particularly limited, but is preferably a melt extrusion method.
  • the melt extrusion method is, for example, an inflation method or a T-die method. Among these, the inflation method is more preferable.
  • a description will be given by taking as an example a method of manufacturing by an inflation method.
  • an unstretched laminate having a multilayer structure is formed.
  • a resin composition for forming a surface layer a resin composition for forming an intermediate layer T1
  • a resin composition for forming a gas barrier layer a resin composition for forming a seal layer
  • an intermediate layer T2 a resin composition for forming resin composition
  • the resin composition for forming each layer of the resin composition for forming the adhesive layer S1 and the resin composition for forming the adhesive layer S2 is put into an extruder and melted.
  • a surface layer is disposed on one surface and a seal layer is disposed on the other surface, and then melt-bonded and coextruded into a tubular shape.
  • the obtained flat tubular unstretched laminate is stretched to form a stretched film.
  • a flat tubular unstretched laminate is heated by, for example, passing through a hot water bath, and then air is blown into the tubular to form a bubble-shaped tubular film, which is cooled with a cold air ring.
  • simultaneous biaxial stretching is performed in the MD direction and the TD direction.
  • the temperature for heat-treating the unstretched laminate is preferably 70 to 95 ° C, more preferably 75 to 90 ° C.
  • the temperature of the cold air ring is preferably 5 to 25 ° C.
  • the stretching ratio is preferably 2 to 4 times in each of the MD direction and the TD direction.
  • the draw ratio in the MD direction and the draw ratio in the TD direction may be the same or different.
  • the method for producing a heat-shrinkable multilayer film according to this embodiment preferably further includes a radiation irradiation step.
  • a radiation irradiation step In the case of irradiation with radiation, stretch film-forming properties, mechanical strength, and the like are improved by the appropriate crosslinking effect.
  • the radiation is, for example, ⁇ rays, ⁇ rays, electron beams (EB), ⁇ rays, and X rays.
  • EB electron beams
  • ⁇ rays X rays.
  • an electron beam and a ⁇ -ray are preferable from the viewpoint of a crosslinking effect before and after irradiation, and an electron beam is particularly preferable from the viewpoints of workability in manufacturing a molded product or high production capacity.
  • the electron beam irradiation conditions may be appropriately set according to the intended use.
  • the electron beam irradiation conditions are preferably an acceleration voltage in the range of 150 to 500 kV and an absorbed dose of 50 to 250 kGy (kilogrey), and more preferably 80 to 200 kGy.
  • the radiation irradiation process may be performed between the lamination process and the stretching process, or may be performed after the stretching process. Further, the irradiation of radiation may be in-line performed after the laminating process or after the stretching process and without the winding process, or may be performed offline after the laminating process or after the stretching process and after the winding process.
  • Table 1 shows the types of resin used. Hereinafter, the abbreviated names shown in Table 1 are used.
  • Table 2 shows the layer configurations of the examples and comparative examples, and Table 3 shows the difference in melting temperature between the surface layer and the seal layer.
  • the measuring method of the melting temperature of resin, a surface layer, and a sealing layer is as follows.
  • the melting temperature of each layer was prepared by peeling or scraping each layer. Moreover, when it was thought that there was no influence on the melting temperature of each layer even if it measured in the state laminated
  • Tm melting temperature
  • DSC8500 differential scanning calorimeter
  • Tm was the endothermic peak of (second temperature increase) in (5) of the temperature program shown below. In addition, when it had a some peak, let the maximum melting peak temperature be Tm.
  • Temperature program (1) Temperature rise at -30 to 200 ° C at 20 ° C / min (2) Hold at 200 ° C for 1 minute (3) Temperature drop from 200 to -30 ° C at 20 ° C / min (4) Hold at -30 ° C for 1 minute (5 ) -30 ⁇ 200 °C Heating at 20 °C / min
  • Example 1 PP-Et-1 as surface layer, EVA-1 as intermediate layer T1, EMA as adhesive layer S1, PVDC as gas barrier layer, EMA as adhesive layer S2, EVA-2 as intermediate layer T2, and Ionomer as seal layer
  • PP-Et-1 as surface layer
  • EVA-1 as intermediate layer T1
  • EMA as adhesive layer S1
  • PVDC as gas barrier layer
  • EMA adhesive layer S2
  • Ionomer as seal layer
  • melt-bonding was performed in order of PP-Et-1 / EVA-1 / EMA / PVDC / EMA / EVA-2 / Ionomer, and coextrusion was performed.
  • the molten tubular body flowing out from the die outlet was cooled by a cold water shower ring at 10 to 20 ° C.
  • the flat tubular body was irradiated with an electron beam in-line in an electron beam irradiation apparatus having an acceleration voltage of 275 kV to give an irradiation dose of 100 kGy.
  • an electron beam irradiation apparatus having an acceleration voltage of 275 kV to give an irradiation dose of 100 kGy.
  • After passing the flat tubular body through a hot water bath at 82 ° C. it is converted into a bubble-shaped tubular body film, and is cooled in a longitudinal direction (MD) by an inflation method while cooling with a cold air ring of 5 to 20 ° C. Simultaneous biaxial stretching was performed at a stretching ratio of 3.4 times in the transverse direction (TD) 4 times.
  • MD longitudinal direction
  • the biaxially stretched film was thermally relaxed to produce a biaxially stretched film (heat-shrinkable multilayer film).
  • the flat width of the obtained heat-shrinkable multilayer film was 340 mm.
  • the layer composition ratio (the value in parentheses is the thickness of each layer) is PP-Et-1 (2.0 ⁇ m) / EVA-1 (22 ⁇ m) / EMA (1.5 ⁇ m) / PVDC (7 ⁇ m) / EMA (1. 5 ⁇ m) / EVA-2 (10 ⁇ m) / Ionomer (10 ⁇ m).
  • the total thickness of the film was 54 ⁇ m.
  • Example 2 PP-Et-1 as surface layer, EVA-1 as intermediate layer T1, EMA as adhesive layer S1, PVDC as gas barrier layer, EMA as adhesive layer S2, EVA-2 as intermediate layer T2, and Ionomer as seal layer
  • melt-bonding was performed in order of PP-Et-1 / EVA-1 / EMA / PVDC / EMA / EVA-2 / Ionomer, and coextrusion was performed.
  • the molten tubular body flowing out from the die outlet was cooled by a cold water shower ring at 10 to 20 ° C.
  • the flat tubular body was irradiated with an electron beam in-line in an electron beam irradiation apparatus having an acceleration voltage of 275 kV to give an irradiation dose of 120 kGy.
  • an electron beam irradiation apparatus having an acceleration voltage of 275 kV to give an irradiation dose of 120 kGy.
  • After passing the flat tubular body through a hot water bath at 82 ° C. it is converted into a bubble-shaped tubular body film, and is cooled in a longitudinal direction (MD) by an inflation method while cooling with a cold air ring of 5 to 20 ° C. Simultaneous biaxial stretching was performed at a draw ratio of 3.2 times in the transverse direction (TD) 7 times.
  • the biaxially stretched film was thermally relaxed to produce a biaxially stretched film (heat-shrinkable multilayer film).
  • the flat width of the obtained heat-shrinkable multilayer film was 380 mm.
  • the layer composition ratio (the value in parentheses is the thickness of each layer) is PP-Et-1 (4.2 ⁇ m) / EVA-1 (35 ⁇ m) / EMA (2.1 ⁇ m) / PVDC (5.6 ⁇ m) / EMA ( 2.1 ⁇ m) / EVA-2 (14 ⁇ m) / Ionomer (14 ⁇ m).
  • the total thickness of the film was 77 ⁇ m.
  • Example 3 Layer composition ratio (numbers in parentheses are the thickness of each layer) PP-Et-1 (2.0 ⁇ m) / Ionomer (22 ⁇ m) / EMA (1.5 ⁇ m) / PVDC (7 ⁇ m) / EMA (in order from the outside to the inside)
  • PP-Et-1 2.0 ⁇ m
  • Ionomer 22 ⁇ m
  • EMA 1.5 ⁇ m
  • PVDC 7 ⁇ m
  • EMA in order from the outside to the inside
  • a heat-shrinkable multilayer film was produced in the same manner as in Example 1 except that the temperature was 1.5 ⁇ m) / EVA-3 (10 ⁇ m) / EVA-2 (10 ⁇ m) and the temperature of the hot water bath was 83 ° C.
  • Example 4 Layer composition ratio (numbers in parentheses are the thickness of each layer) PP-Et-1 (2.0 ⁇ m) / Ionomer (22 ⁇ m) / EMA (1.5 ⁇ m) / PVDC (7 ⁇ m) / EMA (in order from the outside to the inside) 1.5 ⁇ m) / EVA-3 (10 ⁇ m) / EVA-4 (10 ⁇ m) A heat-shrinkable multilayer film was produced in the same manner as in Example 1 except that the temperature of the hot water bath was 83 ° C.
  • Example 5 A heat-shrinkable multilayer film was produced in the same manner as in Example 1 except that the surface layer was changed to PP-Et-2.
  • Example 6 A heat-shrinkable multilayer film was produced in the same manner as in Example 1 except that the surface layer was changed to PP-Et-3.
  • Example 7 A heat-shrinkable multilayer film was produced in the same manner as in Example 1 except that the surface layer was changed to a blend of PP-Et-2 and PP-Et-3 and the blend ratios were 50 wt% and 50 wt%, respectively. did.
  • Example 8 A heat-shrinkable multilayer film was produced in the same manner as in Example 1 except that the surface layer was changed to a blend of PP-Et-4 and PP-Et-5, and the blend ratios were 75 wt% and 25 wt%, respectively. did.
  • Example 2 The layer composition ratio (the values in parentheses are the thickness of each layer) in order from the outside to the inside, LLDPE (2.0 ⁇ m) / EVA-1 (22 ⁇ m) / EMA (1.5 ⁇ m) / PVDC (7 ⁇ m) / EMA (1.
  • a heat-shrinkable multilayer film was produced in the same manner as in Example 1 except that 5 ⁇ m) / EVA-2 (10 ⁇ m) / Ionomer (10 ⁇ m).
  • a film sample marked with a distance of 10 cm in each of the machine direction (longitudinal direction, MD direction) and the direction perpendicular to the machine direction (lateral direction, TD direction) is 80 After being immersed in hot water adjusted to ° C. for 10 seconds, it was taken out and immediately cooled with water at room temperature. Thereafter, the marked distance was measured, and the decrease value from 10 cm was displayed as a percentage as the ratio to the original length of 10 cm. The test was performed 5 times, and the average value in the MD direction and the TD direction was taken as the hot water shrinkage rate.
  • the seal between the seal layers in the film on the side in contact with the seal bar is referred to as an inner surface (upper), and the seal between the seal layers in the film on the side not in contact with the seal bar is referred to as an inner surface (lower).
  • sticker of the surface layers of the overlapping part of two sets of films is called an outer surface.
  • the seal strength of each part was measured using a universal tensile tester (Tensilon RTM-100, manufactured by Orientec Corp.). At this time, the distance between chucks was 20 mm, and the test speed was 300 mm / min. Table 4 shows the seal strength of the inner surface (upper), inner surface (lower), and outer surface at each temperature as the seal strength.
  • the overlap sealability was judged from the seal strengths of the inner surface (upper), inner surface (lower), and outer surface as follows.
  • ⁇ The seal strength of the inner surface (upper) and the inner surface (lower) is 10 N / 15 mm or more, and the strength of the outer surface is 1.5 N / 15 mm or less, indicating a lap seal property (practical level).
  • X The seal strength of the outer surface exceeds 1.5 N / 15 mm, and does not show the overlap sealability (practical level).
  • ⁇ Self-weld property evaluation> (inner self-weld property)
  • the obtained cylindrical film was processed into a bag shape, the inside was evacuated, the opening was sealed, and the ear part when packaging the contents was simulated.
  • the obtained sample was immersed in hot water at 85 ° C. or 95 ° C. for 1 second to shrink, then taken out and immediately cooled in normal temperature water.
  • the contracted sample is left in a constant temperature and humidity chamber at 23 ° C. and 50% relative humidity for 24 hours or more, and then the portion where the inner surfaces of the seal layers are fused is cut to a width of 15 mm, and the length of the fused portion is 30 mm.
  • a sample piece was obtained.
  • the integral average fusing force of the obtained sample pieces was measured for self-weld property at 85 ° C. and self-weld property at 95 ° C. using a universal tensile tester (Tensilon RTM-100, manufactured by Orientec Corp.). At this time, the distance between chucks was 20 mm, and the test speed was 200 mm / min. If the integrated average fusing force is 1 N / 15 mm or more, the self-weldability is at a practical level.
  • Comparative Examples 1, 2, and 3 did not have a propylene-ethylene copolymer in the surface layer, they did not have lap sealing properties.

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  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Engineering & Computer Science (AREA)
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  • Laminated Bodies (AREA)
  • Wrappers (AREA)

Abstract

L'objectif de la présente invention est de fournir un film multicouche thermo-rétractable qui garantit une excellente étanchéité multiple et une excellente auto-soudure et qui combine la thermorétractabilité, des propriétés de barrière contre les gaz et l'aptitude au thermoscellage. Ce film multicouche thermorétractable est doté d'une structure multicouche qui comprend une couche de surface, une couche intermédiaire (T1), une couche de barrière contre les gaz et une couche d'étanchéité et dans laquelle la couche de surface est disposée sur une surface avec la couche d'étanchéité sur l'autre surface, où : la couche de surface comprend un copolymère propylène-éthylène ; la couche de barrière contre le gaz est une résine à base de polychlorure de vinylidène ; et la différence de point de fusion entre la couche de surface et la couche d'étanchéité est de 35 à 60°C.
PCT/JP2013/051849 2012-02-16 2013-01-29 Film multicouche thermorétractable WO2013121874A1 (fr)

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JP2018012253A (ja) * 2016-07-20 2018-01-25 株式会社クレハ 熱収縮性多層フィルム
EP3437833A4 (fr) * 2016-03-31 2019-04-03 Kureha Corporation Film thermorétractable et procédé pour produire un film thermorétractable
WO2023210213A1 (fr) 2022-04-28 2023-11-02 株式会社クレハ Film multicouche thermorétractable et son procédé de production

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WO2000047406A1 (fr) * 1999-02-12 2000-08-17 Kureha Chemical Industry Co., Ltd. Stratifie d'emballage
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WO2016143661A1 (fr) * 2015-03-09 2016-09-15 株式会社クレハ Emballage alimentaire et son procédé de fabrication
EP3437833A4 (fr) * 2016-03-31 2019-04-03 Kureha Corporation Film thermorétractable et procédé pour produire un film thermorétractable
JP2018012253A (ja) * 2016-07-20 2018-01-25 株式会社クレハ 熱収縮性多層フィルム
WO2018016281A1 (fr) * 2016-07-20 2018-01-25 株式会社クレハ Film multicouche thermorétractable
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WO2023210213A1 (fr) 2022-04-28 2023-11-02 株式会社クレハ Film multicouche thermorétractable et son procédé de production

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