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
  • 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
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
  • C08J5/18—Manufacture of films or sheets
• • 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
  • B32B2307/50—Properties of the layers or laminate having particular mechanical properties
  • B32B2307/514—Oriented
• • 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
  • B32B2323/00—Polyalkenes
  • B32B2323/04—Polyethylene
• • 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
  • B32B2323/00—Polyalkenes
  • B32B2323/10—Polypropylene
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
  • Y02W30/00—Technologies for solid waste management
  • Y02W30/50—Reuse, recycling or recovery technologies
  • Y02W30/80—Packaging reuse or recycling, e.g. of multilayer packaging

Definitions

• the present invention relates to a laminated film, and more specifically, to a laminated film having both recyclability and preferable properties as a film such as mechanical strength at a high level and a method for producing the same.
• Olefin-based polymer films such as ethylene-based polymer films are widely used in various applications such as containers, packaging, substrates, and base materials because they are excellent in flexibility, light weight, processability, gas and liquid barrier properties, cost, etc. It is used.
• the plastic materials used for these films have been required to be recyclable from the viewpoint of reducing the environmental load and the like. In recycling, it is preferable that the plastic material is a so-called monomaterial composed of a single type of polymer.
• a film composed only of an ethylene-based polymer is not always excellent in stretchability, and a solution thereof has been studied.
• Patent Document 1 the degree of cross-linking of the polyethylene resin sheet is changed in the thickness direction to improve the stretchability, especially at a low temperature.
• the production of a film in which the degree of cross-linking is changed in the thickness direction complicates the process and is disadvantageous in terms of cost, and cross-linking is not desirable from the viewpoint of recyclability. Therefore, there has been a demand for an olefin-based polymer film that has both recyclability and favorable properties as a film such as mechanical strength and stretchability at a high level, and can be produced relatively easily and at low cost.
• an object of the present invention is an olefin that has both recyclability and favorable properties as a film such as mechanical strength and stretchability at a high level, and can be produced relatively easily and at low cost.
• the present invention is to provide a system polymer film.
• the present inventors have an intermediate layer (A) containing an ethylene-based polymer, and a skin layer (B) containing a propylene-based polymer formed on one or both sides of the intermediate layer (A).
• a laminated film having a specific DSC absorption / heat generation pattern can achieve the above-mentioned problems, and have completed the present invention. That is, the present invention [1] A laminated film having an intermediate layer (A) containing an ethylene-based polymer and a skin layer (B) containing a propylene-based polymer formed on one or both sides of the intermediate layer (A) at 10 ° C./min.
• the half-value width of the crystallization peak observed at 110 ° C. or higher and 125 ° C. or lower in the first temperature lowering stroke is larger than 3.0 ° C.
• the second A laminated film having a melting point Tm 1 of 135 ° C. or higher and 165 ° C. or lower and a melting point Tm 2 of 125 ° C. or higher and lower than 135 ° C. in the heating process is larger than 3.0 ° C.
• [2] to [7] are all preferred embodiments or embodiments of the present invention.
• [2] The laminated film according to [1], wherein the heat of crystal melting ⁇ H in the first temperature lowering stroke of the DSC curve of the ethylene polymer is 180 to 240 J / g.
• a skin layer (B) is formed on one side of the intermediate layer (A), and has a surface layer (C) containing an ethylene polymer provided on the opposite side of the skin layer (B), [1] or The laminated film according to [2].
• the thickness of the skin layer (B) (when the skin layer (B) is present on both sides of the intermediate layer (A), the sum of the thicknesses of both skin layers (B)) is 5 to 60% of the total thickness of the film.
• the laminated film of the present invention has both recyclability and favorable properties as a film such as mechanical strength and stretchability at a high level, can be manufactured relatively easily and at low cost, and reduces the environmental load. However, it can be suitably used in various applications in which a conventional olefin polymer film such as a packaging film is used.
• the present invention is a laminated film having an intermediate layer (A) containing an ethylene-based polymer and a skin layer (B) containing a propylene-based polymer formed on one or both sides of the intermediate layer (A).
• the half-price width of the crystallization peak observed at 110 ° C or higher and 125 ° C or lower in the first temperature lowering stroke of the DSC curve obtained by repeating the temperature rise and fall at ° C / min twice is greater than 3.0 ° C.
• It is a laminated film having a melting point Tm 1 of 135 ° C. or higher and 165 ° C. or lower and a melting point Tm 2 of 125 ° C. or higher and lower than 135 ° C. in the second heating process. That is, the easily openable film of the present invention has an intermediate layer (A) containing an ethylene-based polymer and a skin layer (B) containing a propylene-based polymer.
• the intermediate layer (A) constituting the laminated film of the present invention contains an ethylene-based polymer.
• the intermediate layer (A) may contain an ethylene-based polymer, and therefore may contain a component other than the ethylene-based polymer, and does not contain any component other than the ethylene-based polymer, and all of them are ethylene. It may be composed of a system polymer.
• the intermediate layer (A) may contain only one kind of ethylene-based polymer, or may contain a combination of two or more kinds of ethylene-based polymers.
• Ethylene-based polymer As a preferable example of the ethylene-based polymer, a homopolymer of ethylene, ethylene as a main monomer, and at least one kind of ⁇ -olefin having 3 or more carbon atoms, preferably 3 to 8 carbon atoms or more. Examples thereof include a copolymer with, an ethylene / vinyl acetate copolymer, a saponified product thereof, and an ionomer. Specifically, polyethylene, ethylene / propylene copolymer, ethylene / 1-butene copolymer, ethylene / 1-pentene copolymer, ethylene / 1-hexene copolymer, ethylene / 4-methyl-1-pentene.
• Examples thereof include a copolymer containing ethylene such as a copolymer and an ethylene / 1-octene copolymer as a main monomer, and at least one of ⁇ -olefins having 3 to 8 carbon atoms.
• the proportion of ⁇ -olefins in these copolymers is preferably 1 to 15 mol%.
• the proportion of ethylene-derived constituent units in the ethylene-based polymer is more than 50 mol%, which distinguishes it from the propylene-based polymer described later.
• the density of the ethylene polymer is preferably 0.910 to 0.970 g / cm 3 , more preferably 0.940 to 0.965 g / cm 3 .
• the density is 0.910 g / cm 3 or more, the heat sealability is improved. Further, when the density is 0.970 g / cm 3 or less, processability, toughness and transparency are improved.
• the melting point based on the differential scanning calorimeter (DSC) is in the range of 125 to 135 ° C, especially 128 to 133 ° C, from the viewpoint of the balance between the stretchability and the heat resistance of the obtained laminated film.
• the one is preferable.
• ethylene-based polymer an ethylene polymer manufactured and sold under the name of polyethylene can be mentioned.
• high-pressure method low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and high-density polyethylene (HDPE) are preferable, linear low-density polyethylene and high-density polyethylene are more preferable, and high-density polyethylene is more preferable. Is particularly preferable.
• the high-density polyethylene (HDPE) preferably used as the ethylene-based polymer may be an ethylene homopolymer or a copolymer of ethylene and ⁇ -olefin.
• the high-density polyethylene conforms to JIS K6922-1, and the melt flow rate (hereinafter referred to as MFR) measured at 190 ° C. and a load of 21.18 N is preferably 0.1 to 15 g / 10 minutes, more preferably. Is 0.5 to 10.0 g / 10 minutes, more preferably 1.0 to 5.0 g / 10 minutes.
• MFR melt flow rate
• the high-density polyethylene preferably used in the present embodiment preferably has a density of 940 to 970 kg / m 3 in accordance with JIS K6922-1, more preferably 945 to 970 kg / m 3 , and further preferably 950 to 965 kg / m 3. It is m3 .
• the density is in the above range, the heat resistance is increased such that the film is not deformed by the heat treatment, and the decrease in transparency is small, which is preferable.
• the high-density polyethylene is preferably substantially linear, and has, for example, 0.14 or less long-chain branches per 1000 carbon atoms of the main chain in a fraction having Mn of 100,000 or more when the molecular weight is separated. Is preferable.
• the high-density polyethylene (B) preferably has Mw / Mn in the range of 3.0 to 40.0, and more preferably in the range of 5.0 to 30.0.
• Mw / Mn in the range of 3.0 to 40.0, and more preferably in the range of 5.0 to 30.0.
• the high-density polyethylene preferably used in the present embodiment may be a commercially available product, for example, manufactured by Tosoh Corporation (trade name) Niporon Hard 5700, 8500, 8022, Prime Polymer Co., Ltd. ( Product name) Hi-Zex 3300F and the like can be mentioned.
• the high-density polyethylene preferably used in the present embodiment can be produced by, for example, a production method such as a slurry method, a solution method, or a gas phase method.
• a Cheegler catalyst composed of a solid catalyst component generally containing magnesium and titanium, an organic aluminum compound, and an organic transition metal compound containing a cyclopentadienyl derivative.
• a metallocene catalyst composed of a compound forming an ionic complex and / or an organometallic compound, a vanadium-based catalyst, or the like can be used, and the catalyst is used for homopolymerization of ethylene or copolymerization of ethylene and ⁇ -olefin.
• the ⁇ -olefin may be generally referred to as an ⁇ -olefin, and is an ⁇ -alpha having 3 to 12 carbon atoms such as propylene, butene-1, hexene-1, octene-1, 4-methyl-1-pentene and the like. It is preferably an olefin.
• Examples of the copolymer of ethylene and ⁇ -olefin include ethylene / hexene-1 copolymer, ethylene / butene-1 copolymer, ethylene / octene-1 copolymer and the like.
• the linear low-density polyethylene is usually a copolymer of ethylene and ⁇ -olefin, and may be synthesized by a known production method.
• ⁇ -olefin a compound having 3 to 20 carbon atoms can be used, for example, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-. Decene, 1-dodecene, 4-methyl-1-pentene, 4-methyl-1-hexene and the like can be mentioned, and a mixture thereof may be used.
• the ⁇ -olefin is preferably a compound having 4, 6 or 8 carbon atoms or a mixture thereof, and is 1-butene, 1-hexene, 1-octene or a mixture thereof.
• the linear low-density polyethylene may be a commercially available product, for example, 2040F (C6-LLDPE, MFR; 4.0, density; 0.918 g / cm 3 ) manufactured by Ube-Maruzen Polyethylene Co., Ltd., Prime Polymer Co., Ltd.
• a product (trade name) Evolu SP2040 or the like can be used.
• the density of the linear low-density polyethylene is preferably 0.905 to 0.935 g / cm 3 , more preferably 0.915 to 0.930 g / cm 3 , and the MFR is preferably 0.5 to 0.930 g / cm 3. It is 6.0 g / 10 minutes, more preferably 2.0 to 4.0 g / 10 minutes.
• the linear low-density polyethylene preferably has a molecular weight distribution (weight average molecular weight: Mw, ratio of number average molecular weight: Mn, expressed as Mw / Mn) of 1.5 to 4.0, more preferably. Is in the range of 1.8-3.5. This Mw / Mn can be measured by gel permeation chromatography (GPC).
• Petroleum-derived linear low-density polyethylene can be produced by a conventionally known production method using a conventionally known catalyst such as a multisite catalyst such as a Ziegler catalyst or a single site catalyst such as a metallocene catalyst. From the viewpoint of obtaining a linear low-density polyethylene having a narrow molecular weight distribution and capable of forming a high-strength film, it is preferable to use a single-site catalyst.
• a conventionally known catalyst such as a multisite catalyst such as a Ziegler catalyst or a single site catalyst such as a metallocene catalyst.
• the above-mentioned single-site catalyst is a catalyst capable of forming a uniform active species, and is usually prepared by contacting a metallocene-based transition metal compound or a non-metallocene-based transition metal compound with an activation co-catalyst. ..
• a single-site catalyst is preferable because it has a uniform active site structure as compared with a multi-site catalyst, and can polymerize a polymer having a high molecular weight and a high uniformity structure.
• As the single-site catalyst it is particularly preferable to use a metallocene-based catalyst.
• the metallocene-based catalyst is a catalyst containing a transition metal compound of Group IV of the Periodic Table containing a ligand having a cyclopentadienyl skeleton, a cocatalyst, an organometallic compound if necessary, and each catalyst component of the carrier. be.
• the cyclopentadienyl skeleton is a cyclopentadienyl group, a substituted cyclopentadienyl group or the like.
• the substituted cyclopentadienyl group includes a hydrocarbon group having 1 to 30 carbon atoms, a silyl group, a silyl substituted alkyl group, a silyl substituted aryl group, a cyano group, a cyanoalkyl group, a cyanoaryl group, a halogen group, a haloalkyl group, and a halosilyl.
• the substituted cyclopentadienyl group may have two or more substituents, and the substituents are bonded to each other to form a ring, and an indenyl ring, a fluorenyl ring, an azulenyl ring, a hydrogenator thereof, etc. are formed. It may be formed. Rings formed by bonding substituents to each other may further have substituents to each other.
• transition metal compound of Group IV of the Periodic Table containing a ligand having a cyclopentadienyl skeleton examples include zirconium, titanium and hafnium, and zirconium and hafnium are particularly preferable.
• the transition metal compound usually has two ligands having a cyclopentadienyl skeleton, and the ligands having each cyclopentadienyl skeleton are preferably bonded to each other by a bridging group.
• cross-linking group examples include a substituted silylene group such as an alkylene group having 1 to 4 carbon atoms, a silylene group, a dialkylsilylene group and a diarylcyrylene group, and a substituted gelmilene group such as a dialkylgelmylene group and a diarylgelmylene group. It is preferably a substituted silylene group.
• transition metal compound of Group IV of the periodic table as typical ligands other than the ligand having a cyclopentadienyl skeleton, hydrogen and a hydrocarbon group having 1 to 20 carbon atoms (alkyl group) are typical. , Alkenyl group, aryl group, alkylaryl group, aralkyl group, polyenyl group, etc.), halogen, metaalkyl group, metaaryl group and the like.
• the above-mentioned transition metal compound of Group IV of the Periodic Table containing a ligand having a cyclopentadienyl skeleton can have one or a mixture of two or more as a catalyst component.
• the co-catalyst is one that can effectively use the above-mentioned transition metal compound of Group IV of the Periodic Table as a polymerization catalyst, or can equalize the ionic charge in a catalytically activated state.
• Co-catalysts include benzene-soluble organoxane, which is an organoaluminum oxy compound, benzene-insoluble organoaluminum oxy compound, ion-exchange layered silicate, boron compound, active hydrogen group-containing or non-active hydrogen group-containing or non-coordinating anion. Examples thereof include ionic compounds, lanthanoid salts such as lanthanum oxide, tin oxide, and phenoxy compounds containing a fluoro group.
• the transition metal compound of Group IV of the Periodic Table containing a ligand having a cyclopentadienyl skeleton may be used by being carried on a carrier of an inorganic or organic compound.
• the carrier is preferably a porous oxide of an inorganic or organic compound, and specifically, an ion-exchangeable layered silicate such as montmorillonite, SiO 2 , Al 2 O 3 , MgO, ZrO 2 , TiO 2 , B 2 O. 3 , CaO, ZnO, BaO, ThO 2 , etc. or a mixture thereof can be mentioned.
• organometallic compound used as necessary examples include organoaluminum compounds, organomagnesium compounds, organozinc compounds and the like. Of these, organoaluminum is preferably used.
• the intermediate layer (A) may contain a component other than the above-mentioned ethylene-based polymer, and for example, a polymer other than the ethylene-based polymer, an oligomer, a heat-resistant stabilizer (antioxidant), a weather-resistant stabilizer, and an ultraviolet absorber.
• a component other than the above-mentioned ethylene-based polymer and for example, a polymer other than the ethylene-based polymer, an oligomer, a heat-resistant stabilizer (antioxidant), a weather-resistant stabilizer, and an ultraviolet absorber.
• These additive components may be blended in the ethylene-based polymer in advance, or
• the thickness of the intermediate layer (A) is not particularly limited, but from the viewpoint of film strength and the like, it is preferably 10 ⁇ m or more, more preferably 13 ⁇ m or more, and particularly preferably 15 ⁇ m or more. On the other hand, from the viewpoint of flexibility, economy and the like, the thickness of the intermediate layer (A) is preferably 500 ⁇ m or less, more preferably 300 ⁇ m or less, and particularly preferably 100 ⁇ m or less.
• the thickness of the layer corresponding to the intermediate layer (A) before stretching is preferably 0.2 to 1.94 mm, preferably 0.4 to 1.9 mm. It is particularly preferable to have.
• the thickness of the intermediate layer (A) can be appropriately adjusted by adjusting the stretching conditions such as the stretching ratio, the layer thickness before stretching, the lip spacing of the die of the table forming the layer before stretching, and the like. ..
• the skin layer (B) is formed from the center of the intermediate layer (A) or the center of the intermediate layer (A) and the surface layer (C) before stretching.
• the distance to the interface with) is preferably 0.1 to 1.0 mm, more preferably 0.1 to 0.97 mm, and particularly preferably 0.25 to 0.95 mm.
• the distance from the center of the intermediate layer (A) or the center of the intermediate layer (A) and the surface layer (C) to the interface with the skin layer (B) is the thickness of each layer before stretching and the layer before stretching. It can be adjusted as appropriate by adjusting the lip spacing of the die of the table to be formed.
• the intermediate layer (B) constituting the laminated film of the present invention contains a propylene-based polymer.
• the skin layer (B) may contain a propylene-based polymer, may contain a component other than the propylene-based polymer, and does not contain any component other than the propylene-based polymer, and all of them are propylene-based. It may be composed of a polymer.
• the skin layer (B) may contain only one kind of propylene-based polymer, or may contain a combination of two or more kinds of propylene-based polymers.
• Propylene-based polymer As the propylene-based polymer, a resin generally manufactured and sold under the name of polypropylene can be used, and usually, a propylene homopolymer having a density of about 890 to 930 kg / m 3 or propylene. A copolymer consisting of at least one comonomer selected from other small amounts of ⁇ -olefins and the like can be used together with propylene. In the case of a copolymer, it may be a random copolymer or a block copolymer.
• ⁇ -olefins in this propylene copolymer include ethylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 4-methyl-1-pentene and the like.
• An example thereof is an ⁇ -olefin having about 4 to 20 atoms.
• Such other ⁇ -olefins may be copolymerized alone or in combination of two or more kinds.
• the presence of comonomer other than ⁇ -olefin is not excluded.
• the propylene-based polymer is distinguished from the ethylene-based polymer by the proportion of the constituent units derived from propylene being 50 mol% or more.
• the proportion of the constituent unit derived from propylene is preferably 80 mol% or more, and particularly preferably 90 mol% or more. Since the proportion of the constituent units derived from propylene is 50 mol% or more, the proportion of the constituent units derived from the comonomer is less than 50 mol%. In ordinary polypropylene, the proportion of constituent units derived from comonomer is often 25 mol% or less. In the case of a random copolymer, it is preferably 10 mol% or less, and particularly preferably 7 mol% or less. In the case of block copolymer, it is preferably 20 mol% or less, and particularly preferably 15 mol% or less.
• the melting point based on the differential scanning calorimeter (DSC) is in the range of 135 to 165 ° C, particularly 137 to 163 ° C, from the viewpoint of the balance between the stretchability and the heat resistance of the obtained laminated film.
• a propylene-based polymer is preferable, and a homopolypropylene or a propylene / ⁇ -olefin random copolymer is particularly preferable.
• the melt flow rate (MFR) (ASTM D1238, 230 ° C., 2160 g load) of the propylene-based polymer used in the skin layer (B) is not particularly limited, but is usually 0.01 to 100 g from the viewpoint of stretchability and the like. It is in the range of / 10 minutes, preferably 0.1 to 70 g / 10 minutes.
• the propylene-based polymer (a) can be produced by using various known production methods, specifically, a catalyst for olefin polymerization such as a Ziegler-Natta-based catalyst or a single-site catalyst. In particular, it can be produced using a single-site catalyst.
• the single-site catalyst is a catalyst having a uniform active site (single-site), and examples thereof include a metallocene catalyst (so-called Kaminsky catalyst) and a Brookhart catalyst.
• the metallocene catalyst is a catalyst composed of a metallocene-based transition metal compound and at least one compound selected from the group consisting of an organic aluminum compound and a compound that reacts with the metallocene-based transition metal compound to form an ion pair, and is an inorganic substance. It may be carried.
• the laminated film of the present invention may be a laminated film having an intermediate layer (A) containing an ethylene-based polymer and a skin layer (B) containing a propylene-based polymer formed on one or both sides of the intermediate layer (A). It may or may not have other layers, but particularly when the skin layer (B) is formed on only one side of the intermediate layer (A), what is the skin layer (B)? It is preferable to have a surface layer (C) containing an ethylene-based polymer provided on the opposite side. It is preferable to provide the surface layer (C) because it is possible to impart functionality such as improvement in laminating strength.
• the thickness of the surface layer (C) is not particularly limited, but is preferably 0.1 to 10 ⁇ m, and particularly preferably 1 to 5 ⁇ m.
• the thickness of the surface layer (C) is preferably 1 to 30%, particularly preferably 5 to 20% of the intermediate layer (A).
• the surface layer (C) may be any as long as it contains an ethylene-based polymer, and there are no other restrictions. Therefore, the surface layer (C) may be made of the same material as the intermediate layer (A), but if there is a layer containing two or more ethylene-based polymers, the surface layer (C) is located outside the intermediate layer (A) and has a surface surface.
• the layer constituting the above corresponds to the surface layer (C).
• the details of the type, physical properties, etc. of the ethylene-based polymer in the surface layer (C) are the same as those described above in relation to the intermediate layer (A).
• the laminated film of the present invention is a film having the intermediate layer (A) and the skin layer (B).
• the intermediate layer (A) and the skin layer (B) are preferably directly laminated, but other layers may be present in between. Examples of the other layers include, but are not limited to, an adhesive layer, a gas barrier layer, and the like.
• the thickness of the skin layer (B) (when the skin layer (B) is present on both sides of the intermediate layer (A), the sum of the thicknesses of both skin layers (B)) is the film. It is preferably 5 to 60% of the total thickness. When the thickness of the skin layer (B) occupies 5% or more of the total thickness of the film, the stretchability is improved and stable stretching is possible at a high draw ratio. From this point of view, the thickness of the skin layer (B) (when the skin layer (B) is present on both sides of the intermediate layer (A), the sum of the thicknesses of both skin layers (B)) is 5 of the total film thickness. % Or more is preferable, and 10% or more is particularly preferable.
• the film of the present invention is excellent in recyclability. From this point of view, the thickness of the skin layer (B) (when the skin layer (B) is present on both sides of the intermediate layer (A), the sum of the thicknesses of both skin layers (B)) is 30 of the total film thickness. % Or less, and particularly preferably 10% or less.
• the ratio of the thickness of the skin layer (B) to the total thickness of the film is almost the same before and after stretching, but when there is a difference before and after stretching, there is a difference. It is preferable that the ratio after stretching is within the above range.
• the ratio of the thickness of the skin layer (B) to the total thickness of the film can be appropriately adjusted by adjusting the thickness of each layer before stretching, and the lip spacing of the die when manufacturing each layer before stretching can be adjusted. It is possible to make appropriate adjustments by making adjustments.
• the laminated film of the present invention is obtained by molding various known film forming methods, for example, a film to be an intermediate layer (A) and a skin layer (B) (two layers if there are two layers) in advance, and then forming the film.
• a method of laminating to form a laminated film, a multi-layer film composed of an intermediate layer (A) and a skin layer (B) is obtained using a multilayer die, and then another skin is placed on the surface of the intermediate layer (A).
• a method of extruding the layer (B) to form a laminated film, or a method of obtaining a laminated film composed of a skin layer (B), an intermediate layer (A), and a skin layer (B) by coextrusion using a multilayer die. Can be adopted.
• film forming method various known film forming methods, specifically, a T-die cast film forming method, an inflation film forming method and the like can be adopted.
• the laminated film of the present invention is excellent in stretchability, it is preferable to stretch the laminated film for the purpose of producing a thin film, improving mechanical strength, improving transparency, and the like. It is particularly preferable to perform biaxial stretching.
• the draw ratio is not particularly limited, but in the case of biaxial stretching, it is preferably 2 times ⁇ 2 times or more.
• methods such as sequential biaxial stretching, simultaneous biaxial stretching, and multi-stage stretching are appropriately adopted.
• the conditions for biaxial stretching include known biaxially stretched film production conditions, for example, in the sequential biaxial stretching method, the longitudinal stretching temperature is 100 ° C. to 145 ° C., the stretching ratio is in the range of 3 to 7 times, and the transverse stretching temperature. The temperature is 120 to 180 ° C., and the draw ratio is in the range of 3 to 11 times.
• the total thickness of the laminated film of the present invention is not particularly limited, but from the viewpoint of ensuring practical strength, when stretched, it is usually 15 ⁇ m or more, preferably 18 ⁇ m or more after stretching. More preferably, it is 20 ⁇ m or more. On the other hand, from the viewpoint of having sufficient flexibility in relation to the intended use, it is usually 500 ⁇ m or less, preferably 300 ⁇ m or less, and more preferably 100 ⁇ m or less.
• the total thickness before stretching is preferably 0.3 to 2.5 mm, particularly preferably 0.5 to 2.0 mm.
• the laminated film of the present invention conforms to JIS K7121 and raises the temperature from ⁇ 50 ° C. to 200 ° C. at a heating rate of 10 ° C./min under the conditions of sample weight: about 5.0 mg and nitrogen gas inflow amount: 50 ml / min. After that, the DSC curve obtained by holding at 200 ° C. for 10 minutes and then repeatedly lowering and raising the temperature once under the same conditions has a specific absorption / heat generation pattern.
• the DSC curve obtained under the above conditions is ⁇
• the half-value width of the crystallization peak observed at 110 ° C or higher and 125 ° C or lower in the first temperature lowering stroke is larger than 3.0 ° C, and ⁇ 135 ° C or higher and 165 ° C or lower in the second temperature raising stroke. It has a melting point Tm 1 and a melting point Tm 2 of 125 ° C. or higher and lower than 135 ° C.
• the half-value width of the crystallization peak observed at 110 ° C or higher and 125 ° C or lower is larger than 3.0 ° C in the first temperature lowering stroke, crystallization during stretching can be appropriately suppressed, and stretching processability is possible. It is preferable because it increases.
• the half width of the crystallization peak observed at 110 ° C. or higher and 125 ° C. or lower is preferably 3.0 ° C. or higher, and more preferably 3.5 ° C. or higher.
• the half-price width of the crystallization peak in the first temperature lowering process is determined by changing the types of ethylene-based polymer and propylene-based polymer used, and the ratio of the thickness of the skin layer made of the propylene-based polymer to the entire film. It can be adjusted as appropriate.
• the laminated film of the present invention has a melting point Tm 1 of 135 ° C. or higher and 165 ° C. or lower and a melting point Tm 2 of 125 ° C. or higher and lower than 135 ° C. in the second heating process. Since it has the melting points Tm 1 and Tm 2 , the laminated film of the present invention is suitable for heat sealing. In a laminated film made of only an ethylene polymer, the difference in melting point between the outermost layer and the sealing layer of the film is small, so there is a problem that the outermost layer melts during heat sealing and fuses to the heat seal bar. It has been pointed out in the past.
• the laminated film of the present invention has the melting points Tm 1 and Tm 2 , especially the higher temperature Tm 1 , it is possible to suppress heat fusion of the outermost layer (skin layer (B)) at the time of heat sealing.
• the melting point Tm 1 is preferably 135 to 165 ° C, more preferably 137 to 160 ° C.
• the melting point Tm 1 can be appropriately adjusted by adjusting the type, physical properties, content and the like of the propylene-based polymer contained in the skin layer (B).
• the melting point Tm 2 is preferably 120 to 135 ° C, more preferably 125 to 133 ° C.
• the melting point Tm 2 can be appropriately adjusted by adjusting the type, physical properties, content and the like of the ethylene polymer contained in the intermediate layer (A).
• the heat of crystal melting ⁇ H (converted to 100% of the ethylene polymer ratio) of the ethylene polymer contained in the intermediate layer (A) in the first temperature raising step is 180 to 240 J / g. It is preferable to have.
• the amount of heat of crystal fusion ⁇ H (J / g) of the entire laminated film is observed, so the ⁇ H of the melting peak of the ethylene polymer is divided by the content ratio of the ethylene polymer (PE monomate ratio). Then, the calorific value of crystal melting of the ethylene-based polymer (converted to 100% of the ethylene-based polymer ratio) is obtained.
• the amount of heat of crystal melting ⁇ H of the ethylene-based polymer contained in the intermediate layer (A) in the first heating step is within the above range, because the polyethylene-based polymer is efficiently stretched.
• the amount of heat of crystal melting ⁇ H of the ethylene-based polymer contained in the intermediate layer (A) in the first heating step is more preferably 180 to 240 J / g, and particularly preferably 190 to 230 J / g.
• the amount of heat of crystal melting ⁇ H of the ethylene-based polymer in the first temperature lowering stroke should be appropriately adjusted by adjusting the type of the ethylene-based polymer contained in the intermediate layer (A) and the physical properties such as the degree of crystallization. Can be done.
• the laminated film of the present invention Since the laminated film of the present invention is excellent in stretchability as described above, a high elastic modulus can be realized by utilizing this.
• the laminated film of the present invention has a T1 + T2 value of 1500 (when the elastic modulus in the MD direction (mechanical direction) is T1 and the elastic modulus in the TD direction (lateral direction) is T2 after stretching. It is preferably 1600 (MPa) or more, more preferably 1800 (MPa) or more, and particularly preferably 2000 (MPa) or more.
• T1 + T2 There is no particular upper limit to the value of T1 + T2, but as long as it is manufactured by a material and a manufacturing method that can be obtained at a reasonable cost, it is usually 4500 MPa or less, and in many cases 3500 MPa or less.
• the elastic modulus of the laminated film can be measured by a method conventionally known in the art, and more specifically, it can be measured by performing a tensile test on a strip-shaped sample cut out from the laminated film. For example, it can be measured by the method described in the examples of the present specification.
• the laminated film of this embodiment has a high elastic modulus, it is suitable for use in applications such as packaging bags. Since the packaging bag using the laminated film having such a high elastic modulus has a high so-called elastic feeling, it is possible to realize a packaging bag having a good appearance when displaying products.
• the form of the packaging bag in the present embodiment is not particularly limited and can be appropriately used for a conventionally known packaging bag, and preferred examples thereof include a three-sided bag, a four-sided bag, a pillow bag, a gusset bag, and a standing pouch. be able to. Above all, it can be particularly preferably used in a gusset bag, a standing pouch, etc., which are required to be self-supporting. Further, the high elastic modulus of the present embodiment is preferable because it contributes to excellent processability in the laminating process, the printing process, and the like.
• the laminated film of the present invention preferably has a fusion temperature of 140 ° C. or higher, preferably 150 ° C. or higher, when the fusion temperature is a temperature at which the heat seal strength is 1.0 (N / 15 mm) or higher. Is more preferable, and it is particularly preferable that the temperature is 160 ° C. or higher.
• the heat-sealing strength and heat-sealing temperature of the laminated film can be measured by a method conventionally known in the art, and more specifically, heat-sealed with the adherend film at a predetermined heat-sealing temperature. It can be measured by performing a peeling test on a sample having a width of 15 mm cut out from the obtained laminate. For example, it can be measured by the method described in the examples of the present specification.
• the laminated film of the present invention uses an ethylene-based polymer and a propylene-based polymer having excellent transparency, and the transparency can be further improved by stretching, so that high transparency can be achieved relatively easily. It can be suitably used for applications such as food packaging bags.
• the food packaging bag of the present embodiment has high practical value such as good appearance of printing and contents due to high transparency.
• the contents of the food packaging bag of the present embodiment are not particularly limited, but from the viewpoint of the appearance of the contents, for example, the contents such as rice cake, bread, cut vegetables, cut fruits, and sweets are used.
• the food packaging bag of the present embodiment can be particularly preferably used when storing the contents desired to be shown to the consumer. On the other hand, it is easily crushed by impact during transportation, and it is not always suitable for packaging bags of foods containing contents that you do not want to show, such as snacks and dried small fish, but in that case, it is often packaged. Since printing is performed on the bag, the food packaging bag of the present embodiment having excellent printing appearance can also be used publicly.
• the transparency of the laminated film of the present invention can be evaluated by haze.
• the haze is preferably 10% or less per haze, more preferably 8% or less, still more preferably 5% or less.
• the haze of the laminated film can be measured by a conventionally known method, and more specifically, by the method described in Examples of the present specification.
• the laminated film of the present invention When the laminated film of the present invention is used for a bag for food packaging, it is preferable to use a laminated film having a high tear-opening property.
• examples of the form of the packaging bag include a three-sided bag, a four-sided bag, a pillow bag, a gusset bag, and a standing pouch.
• the value of T1 + T2 is 1000 ( It is preferably mN) or less, more preferably 400 (mN) or less, and particularly preferably 200 (nM) or less.
• the tear strength of the laminated film can be measured by a method conventionally known in the art, and more specifically, it can be measured using a light load tear tester. For example, it can be measured by the method described in the examples of the present application.
• the value of T1 + T2 is preferably 10 (mN) or more, and more preferably 20 (mN) or more, from the viewpoint of avoiding unintentional tearing or the like.
• the laminated film of the present invention has both recyclability and preferable properties as a film such as mechanical strength and stretchability at a high level, and various uses in which an olefin polymer film has been conventionally used.
• it can be suitably used in packaging materials for packaging fresh foods, processed foods, daily necessities, sanitary products, pharmaceuticals, etc., electrical and electronic materials, surface protection materials for various members, etc., and is particularly suitable for use as packaging materials. There is.
• the laminated film of the present invention When the laminated film of the present invention is used as a packaging material, the laminated film itself may be folded and sealed in three directions, or two laminated films may be sealed in all directions to form a package. Further, a laminated film or a lid material obtained by laminating it with a base material or the like may be heat-sealed with various container bodies such as cups to form a package. As a suitable example of such a package, a package container including the above-mentioned lid material and a container body containing at least one of polypropylene, polyethylene terephthalate, and polybutylene terephthalate can be mentioned.
• the items stored in the packaging container are not particularly limited, but can be preferably used for packaging foods, pharmaceuticals, medical devices, daily necessities, miscellaneous goods, and the like.
• the physical properties and characteristics of the examples / comparative examples were evaluated by the following methods.
• (1) Maximum Stretching Magnification A stretched raw film having a thickness of 1 mm was produced in which an intermediate layer (A) and a skin layer (B) were laminated with the layer structure shown in Table 1. Using a batch type biaxial stretching machine, the obtained stretched raw film was subjected to the temperature shown in Table 1 (122 ° C to 166 ° C, 4 ° C intervals) from vertical and horizontal 2 times x 2 times to 9 times x 9 times. Stretching was performed at the same vertical and horizontal magnifications at 0.5-fold intervals, and the maximum magnification that could be stretched without clip detachment or breakage was defined as the maximum stretching ratio at the stretching temperature.
• the temperature was lowered and raised once under the conditions to obtain a DSC curve, from which the melting point (° C.), the amount of heat of crystal melting ⁇ H (J / g), the half-value width of the crystallization peak (° C.), and the like were determined.
• Example 1 Homopolypropylene (h-PP) is supplied as a material constituting the skin layer (B), and high-density polyethylene (HDPE) is supplied as a material constituting the intermediate layer (A) to separate extruders by the T-die method.
• h-PP high-density polyethylene
• HDPE high-density polyethylene
• a three-layer coextruded film having a total thickness of 1.0 mm in which the skin layer (B) / intermediate layer (A) / skin layer (B) has a thickness ratio of 30.0: 40.0: 30.0 is formed.
• a stretched raw film was prepared. Using the obtained stretched raw film, the maximum stretch ratio was evaluated according to the above method. The results are shown in Table 1. Next, the stretched film obtained by stretching the stretched raw film at 158 ° C. 7 ⁇ 7 times was evaluated for haze, elastic modulus, tear strength, and HS strength according to the above method, and a DSC curve was measured. The results are shown in Table 2.
• Example 2 Except that the thickness ratios of the skin layer (B) / intermediate layer (A) / skin layer (B) were changed as shown in Table 1, a stretched raw film was prepared in the same manner as in Example 1. The maximum draw ratio was evaluated. The results are shown in Table 1. Then, in the same manner as in Example 1, a stretched film was prepared from the stretched raw film, the haze, elastic modulus, tear strength, and HS strength were evaluated, and the DSC curve was measured. The results are shown in Table 2.
• Homopolypropylene (h-PP) is used as the material for the skin layer (B), high-density polyethylene (HDPE) is used as the material for the intermediate layer (A), and high-density polyethylene is used as the material for the surface layer (C).
• HDPE high-density polyethylene
• (HDPE) is supplied to separate extruders, and the skin layer (B) / intermediate layer (A) / surface layer (C) has a thickness ratio of 5.0: 90.0: 5.0 by the T-die method.
• a three-layer coextruded film having a total thickness of 1.0 mm was formed to prepare a stretched raw fabric film. Using the obtained stretched raw film, the maximum stretch ratio was evaluated according to the above method. The results are shown in Table 1.
• the stretched film obtained by stretching the stretched raw film at 126 ° C. 6 ⁇ 6 times was evaluated for haze, elastic modulus, tear strength, and HS strength according to the above method, and a DSC curve was measured.
• the heat seal was made by superimposing and sealing the homopolypropylenes of the skin layer (B). The results are shown in Table 2.
• Example 7 Except for the fact that ternary random polypropylene (r-PP1) was used as the material constituting the skin layer (B), a stretched raw film was prepared in the same manner as in Example 4, and the maximum stretching ratio was evaluated. The results are shown in Table 1. Then, in the same manner as in Example 1, a stretched film was prepared from the stretched raw film, the haze, elastic modulus, tear strength, and HS strength were evaluated, and the DSC curve was measured. The results are shown in Table 2. Next, the stretched film obtained by stretching the stretched raw film at 130 ° C. 7 ⁇ 7 times was evaluated for haze, elastic modulus, tear strength, and HS strength according to the above method, and a DSC curve was measured. The results are shown in Table 2. The half width of the first warming process shown in Table 2 is the peak of 117.3 ° C. out of the two peaks.
• r-PP1 ternary random polypropylene
• Example 8 Same as Example 6 except that the positions of the skin layer (B) and the surface layer (C) are exchanged and the ternary random polypropylene (r-PP1) is used as the material constituting the skin layer (B). Then, a stretched raw film was prepared, and the maximum stretching ratio was evaluated. The results are shown in Table 1.
• Example 9 Except for the fact that ternary random polypropylene (r-PP2) or metallocene binary random polypropylene (r-PP3) was used as the material constituting the skin layer (B), the stretched material was the same as in Example 7. An anti-film was prepared and the maximum draw ratio was evaluated. The results are shown in Table 1.
• High-density polyethylene (HDPE) as a material constituting the surface layer (C) and high-density polyethylene (HDPE) as a material constituting the intermediate layer (A) are supplied to separate extruders, and the surface is subjected to the T-die method.
• a three-layer coextruded film having a total thickness of 1.0 mm in which the layer (C) / intermediate layer (A) / surface layer (C) has a thickness ratio of 5.0: 90.0: 5.0 is formed and stretched.
• An anti-film was made. Using the obtained stretched raw film, the maximum stretch ratio was evaluated according to the above method. The results are shown in Table 1.
• the stretched raw film had poor stretchability and could not be made into a stretched film.
• the surface layer (C) / intermediate layer (A) / surface layer (C) has a thickness ratio of 5.0: 90.0: 5.0 by the T-die method.
• An unstretched film having a layer thickness of about 20 ⁇ m was formed, and the haze, elastic modulus, tear strength, and HS strength were evaluated according to the above method, and the DSC curve was measured. The results are shown in Table 2.
• the laminated film of the present invention has both recyclability and favorable properties as a film such as mechanical strength and stretchability at a high level, and can be manufactured relatively easily and at low cost, thus reducing the environmental load.
• it can be suitably used in various applications in which conventional olefin polymer films such as packaging films are used, and can be used in the electrical and electronic industry, pharmaceutical industry, agriculture, food processing industry, distribution, eating out, etc. It has high utility in each field of industry.

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• 2021
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