WO2022138622A1 - 積層フィルム - Google Patents
積層フィルム Download PDFInfo
- Publication number
- WO2022138622A1 WO2022138622A1 PCT/JP2021/047250 JP2021047250W WO2022138622A1 WO 2022138622 A1 WO2022138622 A1 WO 2022138622A1 JP 2021047250 W JP2021047250 W JP 2021047250W WO 2022138622 A1 WO2022138622 A1 WO 2022138622A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- laminated film
- film
- ethylene
- intermediate layer
- layer
- Prior art date
Links
- 238000002844 melting Methods 0.000 claims abstract description 36
- 230000008018 melting Effects 0.000 claims abstract description 36
- 238000001938 differential scanning calorimetry curve Methods 0.000 claims abstract description 18
- 238000002425 crystallisation Methods 0.000 claims abstract description 12
- 230000008025 crystallization Effects 0.000 claims abstract description 12
- 239000010410 layer Substances 0.000 claims description 148
- 229920000642 polymer Polymers 0.000 claims description 68
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 claims description 57
- 239000005977 Ethylene Substances 0.000 claims description 57
- QQONPFPTGQHPMA-UHFFFAOYSA-N propylene Natural products CC=C QQONPFPTGQHPMA-UHFFFAOYSA-N 0.000 claims description 34
- 125000004805 propylene group Chemical group [H]C([H])([H])C([H])([*:1])C([H])([H])[*:2] 0.000 claims description 33
- 239000002344 surface layer Substances 0.000 claims description 22
- 239000013078 crystal Substances 0.000 claims description 9
- 238000010438 heat treatment Methods 0.000 claims description 9
- 238000000034 method Methods 0.000 abstract description 41
- 229920000573 polyethylene Polymers 0.000 abstract description 15
- 229920001155 polypropylene Polymers 0.000 abstract description 11
- 230000008569 process Effects 0.000 abstract description 8
- 230000002349 favourable effect Effects 0.000 abstract description 5
- 229920000098 polyolefin Polymers 0.000 abstract description 5
- 239000010408 film Substances 0.000 description 140
- -1 ethylene, ethylene Chemical group 0.000 description 27
- 239000003054 catalyst Substances 0.000 description 26
- 239000004700 high-density polyethylene Substances 0.000 description 26
- 229920001903 high density polyethylene Polymers 0.000 description 24
- 239000000463 material Substances 0.000 description 20
- 229920001577 copolymer Polymers 0.000 description 19
- 238000004806 packaging method and process Methods 0.000 description 19
- 239000004711 α-olefin Substances 0.000 description 18
- 125000000058 cyclopentadienyl group Chemical group C1(=CC=CC1)* 0.000 description 14
- 150000003623 transition metal compounds Chemical class 0.000 description 13
- 235000013305 food Nutrition 0.000 description 12
- 238000004519 manufacturing process Methods 0.000 description 11
- 239000004743 Polypropylene Substances 0.000 description 10
- 125000004432 carbon atom Chemical group C* 0.000 description 10
- VXNZUUAINFGPBY-UHFFFAOYSA-N ethyl ethylene Natural products CCC=C VXNZUUAINFGPBY-UHFFFAOYSA-N 0.000 description 10
- 238000007789 sealing Methods 0.000 description 10
- 239000003446 ligand Substances 0.000 description 9
- WSSSPWUEQFSQQG-UHFFFAOYSA-N 4-methyl-1-pentene Chemical compound CC(C)CC=C WSSSPWUEQFSQQG-UHFFFAOYSA-N 0.000 description 8
- 229920000092 linear low density polyethylene Polymers 0.000 description 8
- 239000004707 linear low-density polyethylene Substances 0.000 description 8
- LIKMAJRDDDTEIG-UHFFFAOYSA-N n-hexene Natural products CCCCC=C LIKMAJRDDDTEIG-UHFFFAOYSA-N 0.000 description 8
- 229920005629 polypropylene homopolymer Polymers 0.000 description 8
- 150000001875 compounds Chemical class 0.000 description 7
- JRZJOMJEPLMPRA-UHFFFAOYSA-N olefin Natural products CCCCCCCC=C JRZJOMJEPLMPRA-UHFFFAOYSA-N 0.000 description 7
- 230000000737 periodic effect Effects 0.000 description 7
- KWKAKUADMBZCLK-UHFFFAOYSA-N 1-octene Chemical compound CCCCCCC=C KWKAKUADMBZCLK-UHFFFAOYSA-N 0.000 description 6
- 239000000470 constituent Substances 0.000 description 6
- 150000001336 alkenes Chemical class 0.000 description 5
- 230000004927 fusion Effects 0.000 description 5
- 239000000203 mixture Substances 0.000 description 5
- 230000000704 physical effect Effects 0.000 description 5
- 238000007639 printing Methods 0.000 description 5
- YWAKXRMUMFPDSH-UHFFFAOYSA-N propyl ethylene Natural products CCCC=C YWAKXRMUMFPDSH-UHFFFAOYSA-N 0.000 description 5
- 125000001424 substituent group Chemical group 0.000 description 5
- 230000000052 comparative effect Effects 0.000 description 4
- 238000004132 cross linking Methods 0.000 description 4
- 238000009826 distribution Methods 0.000 description 4
- 238000010030 laminating Methods 0.000 description 4
- 239000012968 metallocene catalyst Substances 0.000 description 4
- 229920006254 polymer film Polymers 0.000 description 4
- 239000004698 Polyethylene Substances 0.000 description 3
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 3
- 239000003426 co-catalyst Substances 0.000 description 3
- 230000007613 environmental effect Effects 0.000 description 3
- 239000007789 gas Substances 0.000 description 3
- 239000000155 melt Substances 0.000 description 3
- 238000000465 moulding Methods 0.000 description 3
- TVMXDCGIABBOFY-UHFFFAOYSA-N n-Octanol Natural products CCCCCCCC TVMXDCGIABBOFY-UHFFFAOYSA-N 0.000 description 3
- AFFLGGQVNFXPEV-UHFFFAOYSA-N n-decene Natural products CCCCCCCCC=C AFFLGGQVNFXPEV-UHFFFAOYSA-N 0.000 description 3
- 150000002902 organometallic compounds Chemical class 0.000 description 3
- 239000005022 packaging material Substances 0.000 description 3
- 229920005604 random copolymer Polymers 0.000 description 3
- 125000003808 silyl group Chemical group [H][Si]([H])([H])[*] 0.000 description 3
- ZGEGCLOFRBLKSE-UHFFFAOYSA-N 1-Heptene Chemical compound CCCCCC=C ZGEGCLOFRBLKSE-UHFFFAOYSA-N 0.000 description 2
- CRSBERNSMYQZNG-UHFFFAOYSA-N 1-dodecene Chemical compound CCCCCCCCCCC=C CRSBERNSMYQZNG-UHFFFAOYSA-N 0.000 description 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- CPLXHLVBOLITMK-UHFFFAOYSA-N Magnesium oxide Chemical compound [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 description 2
- BPQQTUXANYXVAA-UHFFFAOYSA-N Orthosilicate Chemical compound [O-][Si]([O-])([O-])[O-] BPQQTUXANYXVAA-UHFFFAOYSA-N 0.000 description 2
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 2
- QCWXUUIWCKQGHC-UHFFFAOYSA-N Zirconium Chemical compound [Zr] QCWXUUIWCKQGHC-UHFFFAOYSA-N 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 2
- 230000004888 barrier function Effects 0.000 description 2
- 229920001400 block copolymer Polymers 0.000 description 2
- 239000003795 chemical substances by application Substances 0.000 description 2
- 229910001873 dinitrogen Inorganic materials 0.000 description 2
- 239000003814 drug Substances 0.000 description 2
- 238000005227 gel permeation chromatography Methods 0.000 description 2
- 229910052735 hafnium Inorganic materials 0.000 description 2
- VBJZVLUMGGDVMO-UHFFFAOYSA-N hafnium atom Chemical compound [Hf] VBJZVLUMGGDVMO-UHFFFAOYSA-N 0.000 description 2
- 230000020169 heat generation Effects 0.000 description 2
- 229920001519 homopolymer Polymers 0.000 description 2
- 150000002430 hydrocarbons Chemical group 0.000 description 2
- 125000004435 hydrogen atom Chemical group [H]* 0.000 description 2
- 150000002484 inorganic compounds Chemical class 0.000 description 2
- MRELNEQAGSRDBK-UHFFFAOYSA-N lanthanum(3+);oxygen(2-) Chemical compound [O-2].[O-2].[O-2].[La+3].[La+3] MRELNEQAGSRDBK-UHFFFAOYSA-N 0.000 description 2
- 229920004889 linear high-density polyethylene Polymers 0.000 description 2
- 229920001684 low density polyethylene Polymers 0.000 description 2
- 239000004702 low-density polyethylene Substances 0.000 description 2
- 239000000178 monomer Substances 0.000 description 2
- 150000002894 organic compounds Chemical class 0.000 description 2
- 229920006280 packaging film Polymers 0.000 description 2
- 239000012785 packaging film Substances 0.000 description 2
- 229920003023 plastic Polymers 0.000 description 2
- 239000004033 plastic Substances 0.000 description 2
- 238000006116 polymerization reaction Methods 0.000 description 2
- 239000011347 resin Substances 0.000 description 2
- 229920005989 resin Polymers 0.000 description 2
- 239000003381 stabilizer Substances 0.000 description 2
- 238000009864 tensile test Methods 0.000 description 2
- 229910052719 titanium Inorganic materials 0.000 description 2
- 239000010936 titanium Substances 0.000 description 2
- 229910052726 zirconium Inorganic materials 0.000 description 2
- YBYIRNPNPLQARY-UHFFFAOYSA-N 1H-indene Natural products C1=CC=C2CC=CC2=C1 YBYIRNPNPLQARY-UHFFFAOYSA-N 0.000 description 1
- SUWJESCICIOQHO-UHFFFAOYSA-N 4-methylhex-1-ene Chemical compound CCC(C)CC=C SUWJESCICIOQHO-UHFFFAOYSA-N 0.000 description 1
- 241000251468 Actinopterygii Species 0.000 description 1
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 239000005909 Kieselgur Substances 0.000 description 1
- 229920010126 Linear Low Density Polyethylene (LLDPE) Polymers 0.000 description 1
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 1
- 240000007594 Oryza sativa Species 0.000 description 1
- 235000007164 Oryza sativa Nutrition 0.000 description 1
- 229910004298 SiO 2 Inorganic materials 0.000 description 1
- 229910010413 TiO 2 Inorganic materials 0.000 description 1
- GEIAQOFPUVMAGM-UHFFFAOYSA-N ZrO Inorganic materials [Zr]=O GEIAQOFPUVMAGM-UHFFFAOYSA-N 0.000 description 1
- 230000004913 activation Effects 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 239000012790 adhesive layer Substances 0.000 description 1
- 125000003342 alkenyl group Chemical group 0.000 description 1
- 125000002877 alkyl aryl group Chemical group 0.000 description 1
- 125000000217 alkyl group Chemical group 0.000 description 1
- 125000002947 alkylene group Chemical group 0.000 description 1
- 150000001450 anions Chemical class 0.000 description 1
- 239000003963 antioxidant agent Substances 0.000 description 1
- 230000003078 antioxidant effect Effects 0.000 description 1
- 239000002216 antistatic agent Substances 0.000 description 1
- 125000003710 aryl alkyl group Chemical group 0.000 description 1
- 125000003118 aryl group Chemical group 0.000 description 1
- 125000004429 atom Chemical group 0.000 description 1
- 125000003828 azulenyl group Chemical group 0.000 description 1
- 150000001639 boron compounds Chemical class 0.000 description 1
- 235000008429 bread Nutrition 0.000 description 1
- 235000009508 confectionery Nutrition 0.000 description 1
- 238000007334 copolymerization reaction Methods 0.000 description 1
- 125000004093 cyano group Chemical group *C#N 0.000 description 1
- 125000004966 cyanoalkyl group Chemical group 0.000 description 1
- 125000002944 cyanoaryl group Chemical group 0.000 description 1
- GUJOJGAPFQRJSV-UHFFFAOYSA-N dialuminum;dioxosilane;oxygen(2-);hydrate Chemical compound O.[O-2].[O-2].[O-2].[Al+3].[Al+3].O=[Si]=O.O=[Si]=O.O=[Si]=O.O=[Si]=O GUJOJGAPFQRJSV-UHFFFAOYSA-N 0.000 description 1
- 229940069096 dodecene Drugs 0.000 description 1
- 239000000975 dye Substances 0.000 description 1
- 235000013399 edible fruits Nutrition 0.000 description 1
- 239000012776 electronic material Substances 0.000 description 1
- HQQADJVZYDDRJT-UHFFFAOYSA-N ethene;prop-1-ene Chemical group C=C.CC=C HQQADJVZYDDRJT-UHFFFAOYSA-N 0.000 description 1
- 239000004744 fabric Substances 0.000 description 1
- 239000000945 filler Substances 0.000 description 1
- 125000003983 fluorenyl group Chemical group C1(=CC=CC=2C3=CC=CC=C3CC12)* 0.000 description 1
- 125000001153 fluoro group Chemical group F* 0.000 description 1
- 125000001188 haloalkyl group Chemical group 0.000 description 1
- 229910052736 halogen Inorganic materials 0.000 description 1
- 125000005843 halogen group Chemical group 0.000 description 1
- 150000002367 halogens Chemical class 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 125000003454 indenyl group Chemical group C1(C=CC2=CC=CC=C12)* 0.000 description 1
- 238000005342 ion exchange Methods 0.000 description 1
- 150000008040 ionic compounds Chemical class 0.000 description 1
- 229920000554 ionomer Polymers 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 239000011980 kaminsky catalyst Substances 0.000 description 1
- 229910052747 lanthanoid Inorganic materials 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000000314 lubricant Substances 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
- 239000011777 magnesium Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 229910052901 montmorillonite Inorganic materials 0.000 description 1
- 239000002667 nucleating agent Substances 0.000 description 1
- 150000002901 organomagnesium compounds Chemical class 0.000 description 1
- 239000003208 petroleum Substances 0.000 description 1
- 125000000951 phenoxy group Chemical group [H]C1=C([H])C([H])=C(O*)C([H])=C1[H] 0.000 description 1
- 239000000049 pigment Substances 0.000 description 1
- 229920001707 polybutylene terephthalate Polymers 0.000 description 1
- 229920013716 polyethylene resin Polymers 0.000 description 1
- 239000005020 polyethylene terephthalate Substances 0.000 description 1
- 229920000139 polyethylene terephthalate Polymers 0.000 description 1
- 239000002685 polymerization catalyst Substances 0.000 description 1
- 229920001384 propylene homopolymer Polymers 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 238000004064 recycling Methods 0.000 description 1
- 235000021067 refined food Nutrition 0.000 description 1
- 235000009566 rice Nutrition 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 239000012748 slip agent Substances 0.000 description 1
- 238000007613 slurry method Methods 0.000 description 1
- 235000011888 snacks Nutrition 0.000 description 1
- 239000011949 solid catalyst Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 125000000547 substituted alkyl group Chemical group 0.000 description 1
- 125000003107 substituted aryl group Chemical group 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
- 239000000454 talc Substances 0.000 description 1
- 229910052623 talc Inorganic materials 0.000 description 1
- 239000010409 thin film Substances 0.000 description 1
- XOLBLPGZBRYERU-UHFFFAOYSA-N tin dioxide Chemical compound O=[Sn]=O XOLBLPGZBRYERU-UHFFFAOYSA-N 0.000 description 1
- 229910001887 tin oxide Inorganic materials 0.000 description 1
- 229910052723 transition metal Inorganic materials 0.000 description 1
- 150000003624 transition metals Chemical class 0.000 description 1
- 239000006097 ultraviolet radiation absorber Substances 0.000 description 1
- 229910052720 vanadium Inorganic materials 0.000 description 1
- LEONUFNNVUYDNQ-UHFFFAOYSA-N vanadium atom Chemical compound [V] LEONUFNNVUYDNQ-UHFFFAOYSA-N 0.000 description 1
- 235000013311 vegetables Nutrition 0.000 description 1
- 238000010792 warming Methods 0.000 description 1
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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Abstract
Description
近年、これらのフィルムに用いられるプラスチック材料には、環境負荷低減等の観点から、リサイクル性が求められるに至っている。リサイクルにおいては、プラスチック材料が単一種の高分子から構成されている、いわゆるモノマテリアルであることが好ましい。
一方で、フィルムの強度や、薄さ等の観点から、オレフィン系重合体フィルムを延伸加工することが広く行われている。しかしながら、エチレン系重合体のみで構成されるフィルムは、その延伸加工性が必ずしも優れたものではなく、その解決が検討されていた。例えば特許文献1では、ポリエチレン樹脂シートの架橋度を厚み方向に変化させることで、特に低温での延伸加工性の向上を実現している。しかし、架橋度を厚み方向に変化させたフィルムの製造は工程を複雑化し、コスト面でも不利であり、また架橋を行うことはリサイクル性の観点からも望ましいものではない。
そこで、リサイクル性と、機械的強度、延伸加工性等のフィルムとして好ましい性質とが高いレベルで両立し、かつ比較的簡便かつ低コストで製造可能なオレフィン系重合体フィルムが求められていた。
すなわち本発明は、
[1]
エチレン系重合体を含む中間層(A)、および中間層(A)の片面または両面に形成されたプロピレン系重合体を含むスキン層(B)を有する積層フィルムであって、10℃/分で昇温及び降温を2回繰り返して得られたDSC曲線の、第1回降温行程において110℃以上、125℃以下に観測される結晶化ピークの半値幅が3.0℃よりも大きく、第2回昇温行程において135℃以上、165℃以下の融点Tm1と125℃以上、135℃未満の融点Tm2とを有する、積層フィルム、
に関する。
[2]
上記エチレン系重合体の、DSC曲線の第1回降温行程における結晶融解熱量ΔHが180~240J/gである、[1]に記載の積層フィルム。
[3]
前記中間層(A)の片面にスキン層(B)が形成され、該スキン層(B)とは反対側に設けられたエチレン系重合体を含む表面層(C)を有する、[1]または[2]に記載の積層フィルム。
[4]
スキン層(B)の厚み(スキン層(B)が中間層(A)の両面に存在する場合には、両スキン層(B)の厚みの和)が、フィルム総厚みの5~60%を占める、[1]から[3]のいずれか一項に記載の積層フィルム。
[5]
延伸前において、中間層(A)の中心、または中間層(A)と表面層(C)との中心から、スキン層(B)との界面までの距離が、0.1から1.0mmである、[3]または[4]に記載の積層フィルム。
[6]
延伸積層フィルムである、[1]から[5]のいずれか一項に記載の積層フィルム。
[7]
延伸倍率が2倍×2倍以上である、[6]に記載の積層フィルム。
すなわち、本発明の易開封性フィルムは、エチレン系重合体を含む中間層(A)、及びプロピレン系重合体を含むスキン層(B)を有する。
本発明の積層フィルムを構成する中間層(A)は、エチレン系重合体を含有する。
中間層(A)は、エチレン系重合体を含有していればよく、したがってエチレン系重合体以外の成分を含有していてもよく、エチレン系重合体以外の成分を含有せずその全てがエチレン系重合体で構成されていてもよい。
中間層(A)は、1種類のみのエチレン系重合体を含有していてもよく、2種類以上のエチレン系重合体の組み合わせを含有していてもよい。
前記エチレン系重合体の好ましい例としては、エチレンの単独重合体、エチレンを主要モノマーとし、それと炭素数3以上、好ましくは炭素数3から8、のα-オレフィンの少なくとも1種類以上との共重合体、エチレン・酢酸ビニル共重合体、そのケン化物及びアイオノマー等が挙げられる。具体的には、ポリエチレン、エチレン・プロピレン共重合体、エチレン・1-ブテン共重合体、エチレン・1-ペンテン共重合体、エチレン・1-ヘキセン共重合体、エチレン・4-メチル-1-ペンテン共重合体、エチレン・1-オクテン共重合体などのエチレンを主要モノマーとし、これと炭素数3から8のα-オレフィンの少なくとも1種類以上との共重合体が挙げられる。これらの共重合体中のα-オレフィンの割合は、1~15モル%であることが好ましい。
エチレン系重合体における、エチレン由来の構成単位の割合は50モル%超となり、この点において後述のプロピレン系重合体から区別される。
MFRが上記範囲にあることで、成形加工時に押出機の負荷が低くなるとともに、成形安定性が向上するので、好ましい。
密度が上記範囲にあることで、加熱処理によりフィルムが変形しない等耐熱性が高くなると共に、透明性の低下が小さくなるので好ましい。
分子量分布が上記範囲内にあると、成形性が良好であるとともの、透明性が向上するため好ましい。
また、Mnが25000以上であると、透明性が向上するため好ましい。
尤も、重合の工程でエチレンを多量化してα-オレフィンを生成させることもでき、この場合は実質的にエチレンのみを原料として製造することもできる。
これらの添加成分は、あらかじめエチレン系重合体に配合されていてもよく、またエチレン系重合体から中間層(A)を形成するにあたって添加してもよい。
一方、可撓性や経済性等の観点からは、中間層(A)の厚みは500μm以下であることが好ましく、300μm以下であることがより好ましく、100μm以下であることが特に好ましい。
本発明の積層フィルムの製造にあたって延伸を行う場合には、延伸前の中間層(A)にあたる層の厚みは、0.2~1.94mmであることが好ましく、0.4~1.9mmであることが特に好ましい。
中間層(A)の厚みは、延伸倍率等の延伸条件や、延伸前の層厚み、当該延伸前の層を形成する台のダイのリップ間隔等を調整することで、適宜調整することができる。
中間層(A)の中心、または中間層(A)と表面層(C)との中心から、スキン層(B)との界面までの距離は、延伸前の各層厚み、当該延伸前の層を形成する台のダイのリップ間隔等を調整することで、適宜調整することができる。
本発明の積層フィルムを構成する中間層(B)は、プロピレン系重合体を含有する。
スキン層(B)は、プロピレン系重合体を含有していればよく、プロピレン系重合体以外の成分を含有していてもよく、プロピレン系重合体以外の成分を含有せずその全てがプロピレン系重合体で構成されていてもよい。
スキン層(B)は、1種類のみのプロピレン系重合体を含有していてもよく、2種類以上のプロピレン系重合体の組み合わせを含有していてもよい。
プロピレン系重合体としては、一般にポリプロピレンの名称で製造・販売されている樹脂を使用することができ、通常、密度が890~930kg/m3程度のプロピレンの単独重合体若しくは、プロピレン共重合体、すなわち、プロピレンと共に、他の少量のα-オレフィン等から選ばれる少なくとも1種以上のコモノマーからなる共重合体を使用することができる。
共重合体である場合においては、ランダム共重合体であってもブロック共重合体であってもよい。このプロピレンの共重合体における他のα-オレフィンとしては、エチレン、1-ブテン、1-ペンテン、1-ヘキセン、1-オクテン、1-デセン、4-メチル-1-ペンテンなどの、エチレンと炭素原子数が4~20程度のα-オレフィンを例示することができる。この様な他のα-オレフィンは、1種単独で又は2種以上のα-オレフィンを組み合わせて共重合させてもよい。また、α-オレフィン以外のコモノマーの存在を排除するものではない。
プロピレン由来の構成単位の割合が50モル%以上であるため、コモノマー由来の構成単位の割合は50モル%未満となる。通常のポリプロピレンにおいては、コモノマー由来の構成単位の割合は25モル%以下となる場合が多い。ランダム共重合体の場合には、10モル%以下であることが好ましく、7モル%以下であることが特に好ましい。ブロック共重合体の場合には、20モル%以下であることが好ましく、15モル%以下であることが特に好ましい。
本発明の積層フィルムは、エチレン系重合体を含む中間層(A)、および中間層(A)の片面または両面に形成されたプロピレン系重合体を含むスキン層(B)を有する積層フィルムであればよく、それ以外の層を有していても有していなくともよいが、特に中間層(A)の片面のみにスキン層(B)が形成されている場合、スキン層(B)とは反対側に設けられたエチレン系重合体を含む表面層(C)を有することが好ましい。
表面層(C)を設けることで、ラミネート強度向上等の機能性を付与することができるため好ましい。
中間層(A)の厚みを基準とした場合、表面層(C)の厚みは、中間層(A)の1~30%であることが好ましく、5~20%であることが特に好ましい。
表面層(C)におけるエチレン系重合体の種類、物性等の詳細は、中間層(A)に関連して上記で説明したものと同様である。
積層フィルム
それ以外の層としては、接着層、ガスバリア層等を例示することができるが、これらには限定されない。
スキン層(B)の厚みがフィルム総厚みの5%以上を占めることで、延伸加工性が向上し、高い延伸倍率で安定した延伸が可能となる。この観点から、スキン層(B)の厚み(スキン層(B)が中間層(A)の両面に存在する場合には、両スキン層(B)の厚みの和)は、フィルム総厚みの5%以上であることが好ましく、10%以上であることが特に好ましい。
スキン層(B)の厚みがフィルム総厚みの60%以下であることで、本発明のフィルムはリサイクル性に優れたものとなる。この観点から、スキン層(B)の厚み(スキン層(B)が中間層(A)の両面に存在する場合には、両スキン層(B)の厚みの和)は、フィルム総厚みの30%以下であることが好ましく、10%以下であることが特に好ましい。
スキン層(B)の厚みがフィルム総厚みに占める割合は、延伸前の各層の厚みを調整することで適宜調整することが可能であり、延伸前の各層を製造する際のダイのリップ間隔を調整することで適宜調整することが可能である。
二軸延伸は、逐次二軸延伸、同時二軸延伸、多段延伸等の方法が適宜採用される。
二軸延伸の条件としては、公知の二軸延伸フィルムの製造条件、例えば、逐次二軸延伸法では、縦延伸温度を100℃~145℃、延伸倍率を3~7倍の範囲、横延伸温度を120~180℃、延伸倍率を3~11倍の範囲とすることが挙げられる。
本発明の積層フィルムが延伸されている場合には、延伸前の総厚みは、0.3~2.5mmであることが好ましく、0.5~2.0mmであることが特に好ましい。
・第1回降温行程において、110℃以上、125℃以下に観測される結晶化ピークの半値幅が3.0℃よりも大きく、かつ
・第2回昇温行程において135℃以上、165℃以下の融点Tm1と125℃以上、135℃未満の融点Tm2とを有する。
第1回降温行程において、110℃以上、125℃以下に観測される結晶化ピークの半値幅は、3.0℃以上であることが好ましく、3.5℃以上であることがより好ましい。
第1回降温行程において、110℃以上、125℃以下に観測される結晶化ピークの半値幅には特に上限は存在しないが、通常10.0℃以下であり、5.0℃以下であることがより好ましい。
第1回降温行程における結晶化ピークの半値幅は、用いるエチレン系重合体、プロピレン系重合体の種類や、プロピレン系重合体から成るスキン層のフィルム全層に対する厚みの比率を変更すること等により適宜調整することができる。
上記融点Tm1及びTm2を有するので、本発明の積層フィルムは、ヒートシール加工に適している。
エチレン系重合体のみからなる積層フィルムでは、当該フィルムの最外層とシール層の融点の差が小さいため、ヒートシール時に最外装が溶融してしまい、ヒートシールバーに融着してしまうという課題が従来より指摘されていた。
本発明の積層フィルムは、上記融点Tm1及びTm2、特により高温であるTm1を有するので、ヒートシール時の最外層(スキン層(B))の熱融着を抑制することができる。例えば、食品包装袋に用いる場合には、製袋適性に優れた食品包装袋を実現することができるので好ましい。
融点Tm1は、135~165℃であることが好ましく、137~160℃であることがより好ましい。
融点Tm1は、スキン層(B)に含まれるプロピレン系重合体の、種類、物性、含有量等を調整することで適宜調整することが可能である。
融点Tm2は、120~135℃であることが好ましく、125~133℃であることがより好ましい。
融点Tm2は、中間層(A)に含まれるエチレン系重合体の、種類、物性、含有量等を調整することで適宜調整することが可能である。
上記DSC曲線においては、積層フィルム全体の結晶融解熱量ΔH(J/g)が観測されるので、エチレン系重合体の融解ピークのΔHをエチレン系重合体の含有割合(PEモノマテ比率)で除して、エチレン系重合体の結晶融解熱量(エチレン系重合体割合100%換算)を求める。
中間層(A)に含まれるエチレン系重合体の、第1回昇温行程における結晶融解熱量ΔHが上記範囲にあることで、ポリエチレン系重合体が効率良く延伸されるため好ましい。
中間層(A)に含まれるエチレン系重合体の、第1回昇温行程における結晶融解熱量ΔHは、180~240J/gであることがより好ましく、190~230J/gであることが特に好ましい。
エチレン系重合体の、第1回降温行程における結晶融解熱量ΔHは、中間層(A)に含まれるエチレン系重合体の種類や、結晶化度等の物性を調整することで、適宜調整することができる。
本発明の積層フィルムは、延伸を行う場合には延伸後において、MD方向(機械方向)の弾性率をT1、TD方向(横方向)の弾性率をT2としたとき、T1+T2の値が1500(MPa)以上であることが望ましく、1600(MPa)以上であることがより好ましく、1800(MPa)以上であることが更に好ましく、2000(MPa)以上であることが特に好ましい。
T1+T2の値には特に上限は存在しないが、合理的なコストで入手可能な材料及び製法で製造する限り、通常4500MPa以下であり、多くの場合3500MPa以下となる。
積層フィルムの弾性率は本技術分野において従来公知の方法により測定することが可能であり、より具体的には積層フィルムから切り出した短冊状の試料で引張試験を行うことにより測定することができる。例えば、本願明細書実施例に記載の方法により測定することができる。
また、本実施形態の高い弾性率は、ラミネート工程や印刷工程などにおける優れた加工性にも寄与するので好ましい。
積層フィルムのヒートシール強度及び熱融着温度は、本技術分野において従来公知の方法で測定することが可能であり、より具体的には所定のヒートシール温度で被着体フィルムとヒートシールして得られた積層体から切り出した15mm幅のサンプルについて、剥離試験を行うことにより測定することができる。例えば、本願明細書の実施例に記載の方法により測定することができる。
一方、輸送中などにおける衝撃で破砕してしまい易く、中身を見せたくない内容物、例えばスナック菓子や乾燥小魚などを含んだ食品の包装袋には必ずしも適さない面もあるが、その場合しばしば包装袋に印刷が行われるので、印刷の見栄えに優れた本実施形態の食品包装袋を、やはり公的に使用することができる。
積層フィルムのヘーズは、従来公知の方法により測定することができ、より具体的には、本願明細書実施例記載の方法により測定することができる。
より具体的には、この実施形態の積層フィルムにおいては、MD方向(機械方向)の引裂強度をT1(mN)、TD方向の引裂強度をT2(mN)としたとき、T1+T2の値が1000(mN)以下であることが好ましく、400(mN)以下であることがより好ましく、200(nM)以下であることが特に好ましい。
積層フィルムの引き裂き強度は、従来当該技術分野において公知の方法で測定することが可能であり、より具体的には、軽荷重引裂き試験機を使用して測定することが可能である。例えば、本願実施例に記載の方法により測定することができる。
積層フィルムの引き裂き強度には特に下限は存在しないが、意図しない破れ等を避ける観点から、T1+T2の値が10(mN)以上であることが好ましく、20(mN)以上であることがより好ましい。
その様な包装体の好適な一例として、上記蓋材とポリプロピレン、ポリエチレンテレフタレート、ポリブチレンテレフタレートのうち少なくとも1種を含む容器本体部からなる包装容器を挙げることができる。
包装容器への収納物には特に制限はないが、食品、医薬品、医療器具、日用品、雑貨等の包装に好ましく用いることができる。
(1)最大延伸倍率
表1に示す層構成で、中間層(A)及びスキン層(B)が積層された、厚さ1mmの延伸原反フィルムを製造した。
バッチ式二軸延伸機を用い、得られた延伸原反フィルムを、表1に示す温度(122℃から166℃、4℃間隔)で、縦横2倍×2倍から9倍×9倍まで、0.5倍間隔の縦横同倍率で延伸を行い、クリップ外れや破断が無く延伸することができた最大倍率を、その延伸温度における最大延伸倍率とした。
(2)ヘーズ
表2に示す延伸温度及び延伸倍率で得られた延伸フィルムについて、ヘーズメーター(日本電色工業(株)社製、NDH5000)を用い、JIS K7136に準拠し、1枚ヘーズおよび4枚ヘーズを測定した。測定値は5回の平均値である。
(3)弾性率
表2に示す延伸温度及び延伸倍率で得られた延伸フィルムから、試験片として、縦方向(MD)及び横方向(TD)に短冊状フィルム片(長さ:150mm、幅:15mm)を切出し、引張り試験機(株式会社エー・アンド・デイ製、RTG1210)を用い、チャック間距離:100mm、クロスヘッドスピード:5mm/分の条件で引張試験を行い、弾性率(MPa)を求めた。測定値は5回の平均値である。
(4)引裂強度
東洋精機製作所社製の軽荷重引裂き試験機を使用して、測定温度23±3℃、測定湿度50±5%RHの条件で、表2に示す延伸温度及び延伸倍率で得られた延伸フィルムのMD方向及びTD方向の引裂き強度をそれぞれ測定した。
(5)ヒートシール強度
表2に示す延伸温度及び延伸倍率で得られた延伸フィルム同士をヒートシール温度を120℃から190℃の範囲で変化させ、幅10mmのシ-ルバ-を用い、0.2MPaの圧力で1秒間シ-ルした後放冷し、測定用サンプルを作成した。サンプルより15mm幅の試験片を切り取り、クロスへッド速度300mm/分でヒ-トシ-ル部を剥離し、その強度をそのヒートシール温度でのヒ-トシ-ル強度(N/15mm)とした。
ヒートシール強度が1.0N以上となる温度を、当該延伸フィルムの融着温度とした。
(6)DSC曲線
示差走査熱量計(DSC)としてティー・エイ・インスツルメント社製Q100を用い、表2に示す延伸温度及び延伸倍率で得られた延伸フィルムから切り取った試料約5mgを精秤し、JISK7121に準拠し、窒素ガス流入量:50ml/分の条件下で、-50℃から加熱速度:10℃/分で200℃まで昇温した後、200℃で10分間保持し、その後同条件で降温及び昇温を1回ずつ繰り返し、DSC曲線を得え、これから融点(℃)、結晶融解熱量ΔH(J/g)、結晶化ピークの半値幅(℃)等を決定した。
・HDPE(高密度ポリエチレン)
密度:950kg/m3
MFR:1.1g/10分
融点:131℃
・h-PP(ホモポリプロピレン)
密度:900kg/m3
MFR:3.0g/10分
融点:161℃
・r-PP1(3元系ランダムポリプロピレン1)
密度:900kg/m3
MFR:7g/10分
融点:139℃
・r-PP2(3元系ランダムポリプロピレン2)
密度:900kg/m3
MFR:5.0g/10分
融点:128℃
・r-PP3(メタロセン2元系ランダムポリプロピレン)
密度:900kg/m3
MFR:7.0g/10分
融点:125℃
スキン層(B)を構成する材料としてホモポリプロピレン(h-PP)を、中間層(A)を構成する材料として高密度ポリエチレン(HDPE)を、それぞれ別々の押出機に供給し、Tダイ法によって、スキン層(B)/中間層(A)/スキン層(B)が厚み比率30.0:40.0:30.0となる、総厚み1.0mmの3層共押出フィルムを成形し、延伸原反フィルムを作製した。
得られた延伸原反フィルムを用いて、上記の方法にしたがって、最大延伸倍率を評価した。結果を表1に示す。
次いで、延伸原反フィルムを158℃で7×7倍に延伸して得られた延伸フィルムについて、上記方法にしたがい、ヘーズ、弾性率、引裂強度、HS強度を評価し、DSC曲線を測定した。結果を表2に示す。
スキン層(B)/中間層(A)/スキン層(B)の厚み比率を表1に示すとおりにそれぞれ変更したことを除くほか、実施例1と同様にして延伸原反フィルムを作製し、最大延伸倍率を評価した。結果を表1に示す。
次いで、実施例1と同様にして、延伸原反フィルムから延伸フィルムを作製し、ヘーズ、弾性率、引裂強度、HS強度を評価し、DSC曲線を測定した。結果を表2に示す。
スキン層(B)を構成する材料としてホモポリプロピレン(h-PP)を、中間層(A)を構成する材料として高密度ポリエチレン(HDPE)を、表面層(C)を構成する材料として高密度ポリエチレン(HDPE)を、それぞれ別々の押出機に供給し、Tダイ法によって、スキン層(B)/中間層(A)/表面層(C)が厚み比率5.0:90.0:5.0となる、総厚み1.0mmの3層共押出フィルムを成形し、延伸原反フィルムを作製した。
得られた延伸原反フィルムを用いて、上記の方法にしたがって、最大延伸倍率を評価した。結果を表1に示す。
次いで、延伸原反フィルムを126℃で6×6倍に延伸して得られた延伸フィルムについて、上記方法にしたがい、ヘーズ、弾性率、引裂強度、HS強度を評価し、DSC曲線を測定した。ヒートシールは、スキン層(B)のホモポリプロピレン同士を重ね合わせてシールした。結果を表2に示す。
スキン層(B)を構成する材料として3元系ランダムポリプロピレン(r-PP1)を使用したことを除くほか、実施例4と同様にして延伸原反フィルムを作製し、最大延伸倍率を評価した。結果を表1に示す。
次いで、実施例1と同様にして、延伸原反フィルムから延伸フィルムを作製し、ヘーズ、弾性率、引裂強度、HS強度を評価し、DSC曲線を測定した。結果を表2に示す。
次いで、延伸原反フィルムを130℃で7×7倍に延伸して得られた延伸フィルムについて、上記方法にしたがい、ヘーズ、弾性率、引裂強度、HS強度を評価し、DSC曲線を測定した。結果を表2に示す。なお、表2に記載の第1回降温行程の半値幅は、2つのピークのうち117.3℃のピークのものである。
スキン層(B)と表面層(C)との位置を入れ替え、スキン層(B)を構成する材料として3元系ランダムポリプロピレン(r-PP1)を使用したことを除くほか、実施例6と同様にして延伸原反フィルムを作製し、最大延伸倍率を評価した。結果を表1に示す。
スキン層(B)を構成する材料として3元系ランダムポリプロピレン(r-PP2)、又はメタロセン2元系ランダムポリプロピレン(r-PP3)を使用したことを除くほか、実施例7と同様にして延伸原反フィルムを作製し、最大延伸倍率を評価した。結果を表1に示す。
表面層(C)を構成する材料として高密度ポリエチレン(HDPE)を、中間層(A)を構成する材料として高密度ポリエチレン(HDPE)、それぞれ別々の押出機に供給し、Tダイ法によって、表面層(C)/中間層(A)/表面層(C)が厚み比率5.0:90.0:5.0となる、総厚み1.0mmの3層共押出フィルムを成形し、延伸原反フィルムを作製した。
得られた延伸原反フィルムを用いて、上記の方法にしたがって、最大延伸倍率を評価した。結果を表1に示す。
上記延伸原反フィルムは延伸加工性が悪く、延伸フィルム化できなかった。そのため、高密度ポリエチレンを押出機に供給し、Tダイ法によって、表面層(C)/中間層(A)/表面層(C)が厚み比率5.0:90.0:5.0となる、層厚み約20μmの無延伸フィルムを成形し、上記方法にしたがい、ヘーズ、弾性率、引裂強度、HS強度を評価し、DSC曲線を測定した。結果を表2に示す。
Claims (7)
- エチレン系重合体を含む中間層(A)、および中間層(A)の片面または両面に形成されたプロピレン系重合体を含むスキン層(B)を有する積層フィルムであって、10℃/分で昇温及び降温を2回繰り返して得られたDSC曲線の、第1回降温行程において110℃以上、125℃以下に観測される結晶化ピークの半値幅が3.0℃よりも大きく、第2回昇温行程において135℃以上、165℃以下の融点Tm1と125℃以上、135℃未満の融点Tm2とを有する、積層フィルム。
- 上記エチレン系重合体の、DSC曲線の第1回降温行程における結晶融解熱量ΔHが180~240J/gである、請求項1に記載の積層フィルム。
- 前記中間層(A)の片面にスキン層(B)が形成され、該スキン層(B)とは反対側に設けられたエチレン系重合体を含む表面層(C)を有する、請求項1または2に記載の積層フィルム。
- スキン層(B)の厚み(スキン層(B)が中間層(A)の両面に存在する場合には、両スキン層(B)の厚みの和)が、フィルム総厚みの5~60%を占める、請求項1から3のいずれか一項に記載の積層フィルム。
- 延伸前において、中間層(A)の中心、または中間層(A)と表面層(C)との中心から、スキン層(B)との界面までの距離が、0.1から1.0mmである、請求項3または4に記載の積層フィルム。
- 延伸積層フィルムである、請求項1から5のいずれか一項に記載の積層フィルム。
- 延伸倍率が2倍×2倍以上である、請求項6に記載の積層フィルム。
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WO2024070894A1 (ja) * | 2022-09-28 | 2024-04-04 | 三井化学東セロ株式会社 | 包装フィルム、包装材および食品包装体 |
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JP2006248148A (ja) * | 2005-03-14 | 2006-09-21 | Mitsui Chemicals Inc | ポリオレフィン系多層フィルム |
JP2014079980A (ja) * | 2012-10-17 | 2014-05-08 | Idemitsu Unitech Co Ltd | 積層シート、加工物、容器及び包装容器 |
WO2019069759A1 (ja) * | 2017-10-03 | 2019-04-11 | 住友ベークライト株式会社 | 多層フィルム及び包装体 |
JP2019142018A (ja) * | 2018-02-16 | 2019-08-29 | 大倉工業株式会社 | 熱収縮性積層フィルム |
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JP2001512384A (ja) * | 1997-02-25 | 2001-08-21 | エクソンモービル・ケミカル・パテンツ・インク | ヒートシール可能なフィルム |
JP2006248148A (ja) * | 2005-03-14 | 2006-09-21 | Mitsui Chemicals Inc | ポリオレフィン系多層フィルム |
JP2014079980A (ja) * | 2012-10-17 | 2014-05-08 | Idemitsu Unitech Co Ltd | 積層シート、加工物、容器及び包装容器 |
WO2019069759A1 (ja) * | 2017-10-03 | 2019-04-11 | 住友ベークライト株式会社 | 多層フィルム及び包装体 |
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WO2024070896A1 (ja) * | 2022-09-28 | 2024-04-04 | 三井化学東セロ株式会社 | 包装フィルム、包装材および食品包装体 |
WO2024070894A1 (ja) * | 2022-09-28 | 2024-04-04 | 三井化学東セロ株式会社 | 包装フィルム、包装材および食品包装体 |
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