CA2961692A1 - Tear resistant mono-axially oriented propylene-based film - Google Patents
Tear resistant mono-axially oriented propylene-based film Download PDFInfo
- Publication number
- CA2961692A1 CA2961692A1 CA2961692A CA2961692A CA2961692A1 CA 2961692 A1 CA2961692 A1 CA 2961692A1 CA 2961692 A CA2961692 A CA 2961692A CA 2961692 A CA2961692 A CA 2961692A CA 2961692 A1 CA2961692 A1 CA 2961692A1
- Authority
- CA
- Canada
- Prior art keywords
- film
- mono
- axially oriented
- layer
- propylene
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- QQONPFPTGQHPMA-UHFFFAOYSA-N propylene Natural products CC=C QQONPFPTGQHPMA-UHFFFAOYSA-N 0.000 title claims description 28
- 125000004805 propylene group Chemical group [H]C([H])([H])C([H])([*:1])C([H])([H])[*:2] 0.000 title claims description 27
- 229920000098 polyolefin Polymers 0.000 claims abstract description 21
- 239000010410 layer Substances 0.000 claims description 62
- 239000003795 chemical substances by application Substances 0.000 claims description 44
- 238000000034 method Methods 0.000 claims description 42
- 239000011800 void material Substances 0.000 claims description 41
- 239000000126 substance Substances 0.000 claims description 25
- 238000005187 foaming Methods 0.000 claims description 24
- 239000004088 foaming agent Substances 0.000 claims description 22
- 229920000642 polymer Polymers 0.000 claims description 19
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 claims description 16
- 239000002245 particle Substances 0.000 claims description 14
- -1 polybutylene terephthalate Polymers 0.000 claims description 14
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 11
- 239000002356 single layer Substances 0.000 claims description 11
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 claims description 10
- 239000011521 glass Substances 0.000 claims description 10
- 230000005540 biological transmission Effects 0.000 claims description 8
- 229910000019 calcium carbonate Inorganic materials 0.000 claims description 8
- 229920000515 polycarbonate Polymers 0.000 claims description 8
- 239000004417 polycarbonate Substances 0.000 claims description 8
- 229920001778 nylon Polymers 0.000 claims description 7
- 239000004677 Nylon Substances 0.000 claims description 6
- 239000004793 Polystyrene Substances 0.000 claims description 6
- 239000011325 microbead Substances 0.000 claims description 6
- 229920001707 polybutylene terephthalate Polymers 0.000 claims description 6
- 229920002223 polystyrene Polymers 0.000 claims description 6
- 238000004519 manufacturing process Methods 0.000 claims description 5
- 238000010899 nucleation Methods 0.000 claims description 5
- 238000009998 heat setting Methods 0.000 claims description 2
- 235000010216 calcium carbonate Nutrition 0.000 claims 2
- 229920001577 copolymer Polymers 0.000 description 22
- 239000012792 core layer Substances 0.000 description 21
- 239000000654 additive Substances 0.000 description 16
- 229920001384 propylene homopolymer Polymers 0.000 description 14
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 description 13
- 239000005977 Ethylene Substances 0.000 description 13
- 238000002844 melting Methods 0.000 description 11
- 230000008018 melting Effects 0.000 description 11
- 239000004594 Masterbatch (MB) Substances 0.000 description 10
- 239000000203 mixture Substances 0.000 description 10
- 229920005989 resin Polymers 0.000 description 10
- 239000011347 resin Substances 0.000 description 10
- 239000000463 material Substances 0.000 description 8
- 238000005266 casting Methods 0.000 description 7
- 229920001971 elastomer Polymers 0.000 description 7
- 239000003348 petrochemical agent Substances 0.000 description 7
- 229920000181 Ethylene propylene rubber Polymers 0.000 description 6
- HQQADJVZYDDRJT-UHFFFAOYSA-N ethene;prop-1-ene Chemical group C=C.CC=C HQQADJVZYDDRJT-UHFFFAOYSA-N 0.000 description 6
- 229920001903 high density polyethylene Polymers 0.000 description 6
- 239000000155 melt Substances 0.000 description 6
- 239000000123 paper Substances 0.000 description 6
- 239000000758 substrate Substances 0.000 description 6
- 229920013665 Ampacet Polymers 0.000 description 5
- SMEGJBVQLJJKKX-HOTMZDKISA-N [(2R,3S,4S,5R,6R)-5-acetyloxy-3,4,6-trihydroxyoxan-2-yl]methyl acetate Chemical compound CC(=O)OC[C@@H]1[C@H]([C@@H]([C@H]([C@@H](O1)O)OC(=O)C)O)O SMEGJBVQLJJKKX-HOTMZDKISA-N 0.000 description 5
- 239000012790 adhesive layer Substances 0.000 description 5
- 238000001125 extrusion Methods 0.000 description 5
- 239000004744 fabric Substances 0.000 description 5
- 238000011068 loading method Methods 0.000 description 5
- 230000000644 propagated effect Effects 0.000 description 5
- 238000009736 wetting Methods 0.000 description 5
- 239000011111 cardboard Substances 0.000 description 4
- 238000002425 crystallisation Methods 0.000 description 4
- 230000008025 crystallization Effects 0.000 description 4
- 239000000806 elastomer Substances 0.000 description 4
- 229920005674 ethylene-propylene random copolymer Polymers 0.000 description 4
- 239000000835 fiber Substances 0.000 description 4
- 229920001519 homopolymer Polymers 0.000 description 4
- 239000012748 slip agent Substances 0.000 description 4
- 238000012360 testing method Methods 0.000 description 4
- PBKONEOXTCPAFI-UHFFFAOYSA-N 1,2,4-trichlorobenzene Chemical compound ClC1=CC=C(Cl)C(Cl)=C1 PBKONEOXTCPAFI-UHFFFAOYSA-N 0.000 description 3
- 241001428800 Cell fusing agent virus Species 0.000 description 3
- 239000004820 Pressure-sensitive adhesive Substances 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 3
- KRKNYBCHXYNGOX-UHFFFAOYSA-N citric acid Chemical compound OC(=O)CC(O)(C(O)=O)CC(O)=O KRKNYBCHXYNGOX-UHFFFAOYSA-N 0.000 description 3
- 239000003086 colorant Substances 0.000 description 3
- 230000000052 comparative effect Effects 0.000 description 3
- 238000000354 decomposition reaction Methods 0.000 description 3
- 238000009472 formulation Methods 0.000 description 3
- 208000036971 interstitial lung disease 2 Diseases 0.000 description 3
- 238000002156 mixing Methods 0.000 description 3
- 229920000728 polyester Polymers 0.000 description 3
- 229920000139 polyethylene terephthalate Polymers 0.000 description 3
- 239000005020 polyethylene terephthalate Substances 0.000 description 3
- 239000004753 textile Substances 0.000 description 3
- VXNZUUAINFGPBY-UHFFFAOYSA-N 1-Butene Chemical compound CCC=C VXNZUUAINFGPBY-UHFFFAOYSA-N 0.000 description 2
- 238000001644 13C nuclear magnetic resonance spectroscopy Methods 0.000 description 2
- UAUDZVJPLUQNMU-UHFFFAOYSA-N Erucasaeureamid Natural products CCCCCCCCC=CCCCCCCCCCCCC(N)=O UAUDZVJPLUQNMU-UHFFFAOYSA-N 0.000 description 2
- 229920000034 Plastomer Polymers 0.000 description 2
- 239000004743 Polypropylene Substances 0.000 description 2
- 239000000853 adhesive Substances 0.000 description 2
- 230000001070 adhesive effect Effects 0.000 description 2
- 230000000903 blocking effect Effects 0.000 description 2
- IAQRGUVFOMOMEM-UHFFFAOYSA-N butene Natural products CC=CC IAQRGUVFOMOMEM-UHFFFAOYSA-N 0.000 description 2
- 238000005520 cutting process Methods 0.000 description 2
- UAUDZVJPLUQNMU-KTKRTIGZSA-N erucamide Chemical compound CCCCCCCC\C=C/CCCCCCCCCCCC(N)=O UAUDZVJPLUQNMU-KTKRTIGZSA-N 0.000 description 2
- 150000002193 fatty amides Chemical class 0.000 description 2
- 230000002349 favourable effect Effects 0.000 description 2
- 239000003063 flame retardant Substances 0.000 description 2
- 230000004927 fusion Effects 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 239000004746 geotextile Substances 0.000 description 2
- 238000010030 laminating Methods 0.000 description 2
- 239000011159 matrix material Substances 0.000 description 2
- 125000002496 methyl group Chemical group [H]C([H])([H])* 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- LYRFLYHAGKPMFH-UHFFFAOYSA-N octadecanamide Chemical compound CCCCCCCCCCCCCCCCCC(N)=O LYRFLYHAGKPMFH-UHFFFAOYSA-N 0.000 description 2
- 238000004806 packaging method and process Methods 0.000 description 2
- 239000011087 paperboard Substances 0.000 description 2
- 239000000049 pigment Substances 0.000 description 2
- 229920003229 poly(methyl methacrylate) Polymers 0.000 description 2
- 239000004926 polymethyl methacrylate Substances 0.000 description 2
- 229920001155 polypropylene Polymers 0.000 description 2
- 229920002545 silicone oil Polymers 0.000 description 2
- 238000009941 weaving Methods 0.000 description 2
- BVKZGUZCCUSVTD-UHFFFAOYSA-M Bicarbonate Chemical compound OC([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-M 0.000 description 1
- 229920002799 BoPET Polymers 0.000 description 1
- 101100439208 Caenorhabditis elegans cex-1 gene Proteins 0.000 description 1
- 229920000089 Cyclic olefin copolymer Polymers 0.000 description 1
- 241000755266 Kathetostoma giganteum Species 0.000 description 1
- BPQQTUXANYXVAA-UHFFFAOYSA-N Orthosilicate Chemical compound [O-][Si]([O-])([O-])[O-] BPQQTUXANYXVAA-UHFFFAOYSA-N 0.000 description 1
- 239000004698 Polyethylene Substances 0.000 description 1
- 206010040880 Skin irritation Diseases 0.000 description 1
- VEUACKUBDLVUAC-UHFFFAOYSA-N [Na].[Ca] Chemical compound [Na].[Ca] VEUACKUBDLVUAC-UHFFFAOYSA-N 0.000 description 1
- 239000002390 adhesive tape Substances 0.000 description 1
- 239000001055 blue pigment Substances 0.000 description 1
- 230000009172 bursting Effects 0.000 description 1
- 235000012215 calcium aluminium silicate Nutrition 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000004512 die casting Methods 0.000 description 1
- 229920001038 ethylene copolymer Polymers 0.000 description 1
- 125000000816 ethylene group Chemical group [H]C([H])([*:1])C([H])([H])[*:2] 0.000 description 1
- 239000006260 foam Substances 0.000 description 1
- 239000002778 food additive Substances 0.000 description 1
- 235000013373 food additive Nutrition 0.000 description 1
- 239000003365 glass fiber Substances 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 239000004700 high-density polyethylene Substances 0.000 description 1
- 150000002429 hydrazines Chemical class 0.000 description 1
- 238000007654 immersion Methods 0.000 description 1
- 230000000977 initiatory effect Effects 0.000 description 1
- 229910052500 inorganic mineral Inorganic materials 0.000 description 1
- 239000010954 inorganic particle Substances 0.000 description 1
- 229920000092 linear low density polyethylene Polymers 0.000 description 1
- 229920001684 low density polyethylene Polymers 0.000 description 1
- 239000004702 low-density polyethylene Substances 0.000 description 1
- 229920001179 medium density polyethylene Polymers 0.000 description 1
- 239000004701 medium-density polyethylene Substances 0.000 description 1
- 230000001617 migratory effect Effects 0.000 description 1
- 239000011707 mineral Substances 0.000 description 1
- 239000003921 oil Substances 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 239000005026 oriented polypropylene Substances 0.000 description 1
- 239000008188 pellet Substances 0.000 description 1
- 229920003217 poly(methylsilsesquioxane) Polymers 0.000 description 1
- 229920000573 polyethylene Polymers 0.000 description 1
- 229920002959 polymer blend Polymers 0.000 description 1
- 238000010094 polymer processing Methods 0.000 description 1
- 229920005672 polyolefin resin Polymers 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 238000007639 printing Methods 0.000 description 1
- 230000001902 propagating effect Effects 0.000 description 1
- 229920005675 propylene-butene random copolymer Polymers 0.000 description 1
- 238000010791 quenching Methods 0.000 description 1
- 230000000171 quenching effect Effects 0.000 description 1
- 230000035484 reaction time Effects 0.000 description 1
- 238000004064 recycling Methods 0.000 description 1
- 230000002787 reinforcement Effects 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 229920005573 silicon-containing polymer Polymers 0.000 description 1
- 230000036556 skin irritation Effects 0.000 description 1
- 231100000475 skin irritation Toxicity 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 238000001228 spectrum Methods 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
- 229940037312 stearamide Drugs 0.000 description 1
- 229920002994 synthetic fiber Polymers 0.000 description 1
- 239000012209 synthetic fiber Substances 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
- 229920001169 thermoplastic Polymers 0.000 description 1
- 229920002725 thermoplastic elastomer Polymers 0.000 description 1
- 239000004416 thermosoftening plastic Substances 0.000 description 1
- 239000004408 titanium dioxide Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
- 238000005303 weighing Methods 0.000 description 1
- 238000004804 winding Methods 0.000 description 1
- 239000004711 α-olefin Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
- C08L23/02—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers not modified by chemical after-treatment
- C08L23/10—Homopolymers or copolymers of propene
- C08L23/12—Polypropene
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B27/00—Layered products comprising a layer of synthetic resin
- B32B27/06—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material
- B32B27/08—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B27/00—Layered products comprising a layer of synthetic resin
- B32B27/16—Layered products comprising a layer of synthetic resin specially treated, e.g. irradiated
-
- 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
- B32B27/18—Layered products comprising a layer of synthetic resin characterised by the use of special additives
-
- 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
- B32B27/18—Layered products comprising a layer of synthetic resin characterised by the use of special additives
- B32B27/20—Layered products comprising a layer of synthetic resin characterised by the use of special additives using fillers, pigments, thixotroping agents
-
- 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
- B32B27/18—Layered products comprising a layer of synthetic resin characterised by the use of special additives
- B32B27/20—Layered products comprising a layer of synthetic resin characterised by the use of special additives using fillers, pigments, thixotroping agents
- B32B27/205—Layered products comprising a layer of synthetic resin characterised by the use of special additives using fillers, pigments, thixotroping agents the fillers creating voids or cavities, e.g. by stretching
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B27/00—Layered products comprising a layer of synthetic resin
- B32B27/32—Layered products comprising a layer of synthetic resin comprising polyolefins
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B29/00—Layered products comprising a layer of paper or cardboard
- B32B29/002—Layered products comprising a layer of paper or cardboard as the main or only constituent of a layer, which is next to another layer of the same or of a different material
-
- 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
- B32B29/00—Layered products comprising a layer of paper or cardboard
- B32B29/002—Layered products comprising a layer of paper or cardboard as the main or only constituent of a layer, which is next to another layer of the same or of a different material
- B32B29/007—Layered products comprising a layer of paper or cardboard as the main or only constituent of a layer, which is next to another layer of the same or of a different material next to a foam layer
-
- 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
- B32B29/00—Layered products comprising a layer of paper or cardboard
- B32B29/08—Corrugated paper or cardboard
-
- 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
- B32B3/00—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar form; Layered products having particular features of form
- B32B3/26—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar form; Layered products having particular features of form characterised by a particular shape of the outline of the cross-section of a continuous layer; characterised by a layer with cavities or internal voids ; characterised by an apertured layer
-
- 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
- B32B3/00—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar form; Layered products having particular features of form
- B32B3/26—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar form; Layered products having particular features of form characterised by a particular shape of the outline of the cross-section of a continuous layer; characterised by a layer with cavities or internal voids ; characterised by an apertured layer
- B32B3/28—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar form; Layered products having particular features of form characterised by a particular shape of the outline of the cross-section of a continuous layer; characterised by a layer with cavities or internal voids ; characterised by an apertured layer characterised by a layer comprising a deformed thin sheet, i.e. the layer having its entire thickness deformed out of the plane, e.g. corrugated, crumpled
-
- 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
- B32B5/00—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts
- B32B5/02—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by structural features of a fibrous or filamentary layer
- B32B5/022—Non-woven fabric
-
- 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
- B32B5/00—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts
- B32B5/02—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by structural features of a fibrous or filamentary layer
- B32B5/028—Net structure, e.g. spaced apart filaments bonded at the crossing points
-
- 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
- B32B5/00—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts
- B32B5/18—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by features of a layer of foamed material
-
- 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
- B32B5/00—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts
- B32B5/22—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by the presence of two or more layers which are next to each other and are fibrous, filamentary, formed of particles or foamed
-
- 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
- B32B5/00—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts
- B32B5/22—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by the presence of two or more layers which are next to each other and are fibrous, filamentary, formed of particles or foamed
- B32B5/24—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by the presence of two or more layers which are next to each other and are fibrous, filamentary, formed of particles or foamed one layer being a fibrous or filamentary layer
- B32B5/245—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by the presence of two or more layers which are next to each other and are fibrous, filamentary, formed of particles or foamed one layer being a fibrous or filamentary layer another layer next to it being a foam layer
-
- 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
- B32B5/00—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts
- B32B5/22—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by the presence of two or more layers which are next to each other and are fibrous, filamentary, formed of particles or foamed
- B32B5/32—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by the presence of two or more layers which are next to each other and are fibrous, filamentary, formed of particles or foamed at least two layers being foamed and next to each other
-
- 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
- B32B2264/00—Composition or properties of particles which form a particulate layer or are present as additives
- B32B2264/10—Inorganic particles
- B32B2264/101—Glass
-
- 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
- B32B2264/00—Composition or properties of particles which form a particulate layer or are present as additives
- B32B2264/10—Inorganic particles
- B32B2264/102—Oxide or hydroxide
-
- 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
- B32B2264/00—Composition or properties of particles which form a particulate layer or are present as additives
- B32B2264/10—Inorganic particles
- B32B2264/104—Oxysalt, e.g. carbonate, sulfate, phosphate or nitrate particles
-
- 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
- B32B2266/00—Composition of foam
- B32B2266/02—Organic
- B32B2266/0214—Materials belonging to B32B27/00
- B32B2266/025—Polyolefin
-
- 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
- B32B2270/00—Resin or rubber layer containing a blend of at least two different polymers
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2274/00—Thermoplastic elastomer material
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2307/00—Properties of the layers or laminate
- B32B2307/30—Properties of the layers or laminate having particular thermal properties
-
- 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
- B32B2307/40—Properties of the layers or laminate having particular optical properties
- B32B2307/402—Coloured
-
- 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
- B32B2307/40—Properties of the layers or laminate having particular optical properties
- B32B2307/406—Bright, glossy, shiny surface
-
- 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
- B32B2307/516—Oriented mono-axially
-
- 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
- B32B2307/54—Yield strength; Tensile strength
-
- 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
- B32B2307/582—Tearability
- B32B2307/5825—Tear resistant
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2307/00—Properties of the layers or laminate
- B32B2307/70—Other properties
- B32B2307/72—Density
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2307/00—Properties of the layers or laminate
- B32B2307/70—Other properties
- B32B2307/732—Dimensional properties
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2307/00—Properties of the layers or laminate
- B32B2307/70—Other properties
- B32B2307/732—Dimensional properties
- B32B2307/734—Dimensional stability
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2439/00—Containers; Receptacles
- B32B2439/40—Closed containers
- B32B2439/62—Boxes, cartons, cases
-
- 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
- B32B2553/00—Packaging equipment or accessories not otherwise provided for
-
- 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
- C08J2323/00—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers
- C08J2323/02—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers not modified by chemical after treatment
- C08J2323/10—Homopolymers or copolymers of propene
- C08J2323/12—Polypropene
-
- 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
- C08J2323/00—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers
- C08J2323/02—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers not modified by chemical after treatment
- C08J2323/10—Homopolymers or copolymers of propene
- C08J2323/14—Copolymers of propene
-
- 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
- C08J2423/00—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers
- C08J2423/02—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers not modified by chemical after treatment
- C08J2423/10—Homopolymers or copolymers of propene
- C08J2423/12—Polypropene
-
- 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
- C08J2423/00—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers
- C08J2423/02—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers not modified by chemical after treatment
- C08J2423/10—Homopolymers or copolymers of propene
- C08J2423/14—Copolymers of propene
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L2203/00—Applications
- C08L2203/14—Applications used for foams
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- Manufacturing & Machinery (AREA)
- Textile Engineering (AREA)
- Materials Engineering (AREA)
- Manufacture Of Porous Articles, And Recovery And Treatment Of Waste Products (AREA)
- Laminated Bodies (AREA)
Abstract
Described is a mono-axially oriented polyolefin film including a core or base layer containing a plurality of voids formed by a cavitating agent, wherein the film is oriented at least 4 times in the machine direction, and exhibits excellent tear resistance in the transverse direction.
Description
TEAR RESISTANT MONO-AXIALLY ORIENTED PROPYLENE-BASED FILM
Field [0001] This disclosure relates to a mono-axially oriented propylene-based film which exhibits excellent tear resistance and methods of making the same. More particularly, this invention relates to a mono-axially oriented, voided film that exhibits excellent tear resistance formed from the blending of a voiding agent.
Background
Field [0001] This disclosure relates to a mono-axially oriented propylene-based film which exhibits excellent tear resistance and methods of making the same. More particularly, this invention relates to a mono-axially oriented, voided film that exhibits excellent tear resistance formed from the blending of a voiding agent.
Background
[0002] Polymeric-based films can be used to form tapes for strapping heavy and bulky articles such as cartons. In addition, polymeric-based films can be used to reinforce other substrates such as corrugated cardboard, cardboard or paperboard backings for blister packages, boxes, or envelopes. Furthermore, polymeric-based films can be used as, or incorporated as part of, handles for carrying cartons, boxes, bags, or other bulk containers.
Polymeric-based films can also be used as substrates for adhesive-coated tapes and narrow-width strips ("weaving tapes") that can be used in woven articles such as sacks, bags, baskets, geo-textiles, geo-grids, fabrics, and self-reinforced composites.
Polymeric-based films can also be used as substrates for adhesive-coated tapes and narrow-width strips ("weaving tapes") that can be used in woven articles such as sacks, bags, baskets, geo-textiles, geo-grids, fabrics, and self-reinforced composites.
[0003] For example, US Patent 2,750,030 describes a high strength pressure-sensitive adhesive strapping tape with a lengthwise tensile strength of at least 300 lbs/in. The tape has a high cross-wise tear strength and a thickness of 5-20 mil. The tape has a film or paper backing coated with a tacky rubber-resin pressure-sensitive adhesive which contains an embedded monolayer of loosely-twisted or non-twisted yarns of continuous hair-like glass filaments that extend continuously from one end of the tape to the other. The cross-wise tear strength of the tape is due to the presence of the glass filaments aligned length-wise.
[0004] US Patent 2,753,284 describes a lineally reinforced, high-tensile adhesive tape for strapping tape applications and has a tensile strength of at least 100 lbs/in.
The tape has a paper sheet with two layers of a rubber-resin type pressure-sensitive tacky adhesive in which mono-fiber hair-like glass filaments are embedded between the two tacky adhesive layers. A non-tacky third adhesive layer is coated over the outermost tacky adhesive layer. The cross-wise tear strength of the tape is due to the presence of the glass filaments aligned linearly.
The tape has a paper sheet with two layers of a rubber-resin type pressure-sensitive tacky adhesive in which mono-fiber hair-like glass filaments are embedded between the two tacky adhesive layers. A non-tacky third adhesive layer is coated over the outermost tacky adhesive layer. The cross-wise tear strength of the tape is due to the presence of the glass filaments aligned linearly.
[0005] US Patent 4,905,888 describes a handle for packages or cartons comprising strap-type foldable carrying tape. The strap-type carrying tape is preferably formed from a pressure-sensitive adhesive tape and can be made of woven natural or synthetic fibers.
The carrying tape can also be reinforced with filament fibers or strips for tear resistance.
The carrying tape can also be reinforced with filament fibers or strips for tear resistance.
[0006] US Patent 7,144,635 describes a tear-resistant laminate comprised of paper or paper-board substrate, an adhesive layer, a tear-resistant layer secured to the adhesive layer, and a heat-sealable layer. The tear-resistant layer has a tear strength of at least 300 gf in both machine and cross-direction as measured by Elmendorf tear propation test. The tear-resistant layer is a polymeric material and can be biaxially oriented films such as polyester, nylon, polyolefin, or high density polyolefins such as metallocene-catalyzed polyethylene.
[0007] US Patent Application Serial No. 14/364,677 (US publication number US
2014/0322463) describes a uni-directionally oriented film comprised of a thermoplastic polyester and a polycarbonate. This type of film can be used for strapping of cartons, boxes, pallets, etc., and may be used as a weaving tape for woven bags, sacks, and containers.
Preferably, the polyester is a polyethylene terephthalate (PET) resin. Polycarbonate is blended into the PET film as a minority component to reduce the tendency of such PET unidirectionally oriented films from splitting along the machine direction axis and imparts some impact toughness.
Summary 100081 Disclosed herein is a novel polyolefin-based, monoaxially (or uni-axially) oriented film that can be suitable for strapping tape applications and/or other applications requiring high tear resistance. In some embodiments, the film can have a high resistance to cross-direction (or transverse direction, TD) tearing and can have a machine direction (MD) tensile strength of greater than about 75, 80, 85, or 90 lbs/inch width and less than about 130, 120, 115, 110 or 100 lbs/inch width. Preferably, the polyolefin can be a propylene-based polymer.
The tear resistance may be imparted by voiding of the film in which the voids interrupt or halt tear propagation through the film. Without being bound by any theory, it is believed that the voids provide termination points for crack/tear propagation and redirects the energy of the tear propagation from cross-wise (or transverse-wise) perpendicularly to the machine direction (along the direction of the monoaxial orientation) as depicted by Figure 1. It is also believed that the size and shape of these voids can play a role in the effectiveness of terminating tear propagation, with smaller, more ovoid or oblong voids being preferred. This can result in a film with very high cross-wise or transverse direction tear resistance without using machine-direction aligned and embedded fibers or filaments to impart transverse direction tear resistance as in the prior arts. In particular, the inventors have found that the disclosed films exhibit very good transverse tear resistance even if the film is nicked or cut on the edges of the film to initiate a transverse tear.
[0009] The described films may be simpler to produce than typical films and tapes. In some embodiments, the films can be produced without requiring the use -- or additional processing steps ¨ of embedding fibers or filaments. Because the film may not include any foreign matter such as glass fibers, the film can be more suitable for recycling scrap or spent material for other uses or as part of the production of new strapping tape.
[0010] In an embodiment, a single layer film may be extruded and mono-axially oriented in the machine direction. This single layer can be voided, which provides the transverse direction tear resistance. In additional multi-layer film embodiments, it is contemplated to coextrude one or more skin layers on one or both sides of a void-containing core or base layer which is mono-axially oriented in the machine direction. This voided core layer can provide the transverse direction tear resistance properties of the multi-layer film. Further embodiments include voiding of the coexruded skin layers or intermediate layers adjacent to the core layer as well. It can also be contemplated to void the skin layers for tear propagation resistance while leaving the core layer un-voided. However, the core layer can be the preferred layer for voiding as it represents the bulk of the film mass and the bulk of the voids to terminate crack/tear propagation. It can be preferred that the coextruded skin layers be un-voided to provide smoother outer surfaces more suitable for printing, laminating, coating, metallizing, or other process handling. Other embodiments of the disclosed films can include laminating the disclosed films to other substrates including, but not limited to: other unvoided polymeric films or articles, paper-containing substrates, cardboard-containing substrates, fabric textiles, non-woven textiles, meshes, tapes, etc.
[0011] Voiding of the disclosed films can be accomplished by several means, including but not limited to: 1) cavitating agents such as inorganic particles like CaCO3, Ti02, silica particles, glass micro-beads; 2) cavitating agents such as organic polymeric materials like polybutylene terephthalate, nylons, polycarbonates, polystyrenes, polymethlymethacrylate;
3) beta-nucleation of the propylene-based polymer; 4) chemical foaming agents; or 5) combinations of the above. A
preferred embodiment can be to use chemical foaming agents which provide relatively large voids or closed-cell cavities in which there is no physical particle residing within said void. Such an embodiment can help reduce the overall density of the voided film in comparison to a voided film using inorganic or polymeric cavitating agents wherein such cavitating agents add their intrinsic material density to the overall film density.
[0012] The film can also incorporate optional amounts of additives, including but not limited to: antiblock additives, slip additives, coloring agents/pigments, antistatic additives, UV-light absorbing or blocking additives, fire retardant additives.
[0013] Embodiments of a mono-axially oriented polyolefin film may comprise a core layer containing a plurality of voids. The film is oriented at least 4 times in the machine direction, and exhibits excellent tear resistance in the transverse direction.
[0014] In some embodiments, the film comprises at least one skin layer. The at least one skin layer may be voided or unvoided. In some embodiments, the core layer comprises a propylene-based polymer.
[0015] In some embodiments, the core layer comprises CaCO3, Ti02, silica particles, or glass micro-beads inorganic voiding particles. In some embodiments, the core layer comprises polymeric cavitating or voiding agents such as polybutylene terephthalate, nylon, polycarbonate, polystyrene, or polymethlymethacrylate. In some embodiments, the core layer comprises a propylene-based polymer and beta-nucleation of the propylene-based polymer to form a plurality of voids. In some embodiments, the core layer comprises a chemical foaming agent as the voiding agent.
[0016] In some embodiments, the film has a machine direction (MD) tensile strength of greater than about 75 lbsf/linear inch width, greater than about 85 lbsf/linear inch width, greater than about 95 lbsf/linear inch width, or greater than about 100 lbsf/linear inch width. In some embodiments, the film has a machine direction tensile strength of about 75-130 lbsf/linear inch width, about 85-130 lbsf/linear inch width, about 95-130 lbsf/linear inch width, or about 100-130 lbsf/linear inch width.
[0017] In some embodiments, the film is a mono-layer film and has a thickness of 1.5 - 10.0 mil (37.5 ¨ 250 pm) or 2.5 ¨ 5.0 mil before foaming and a thickness of about 2.5 - 18.5 mil (62.5 ¨ 462.5 pm) or 3.0 ¨ 5.0 mil after foaming.
[0018] In some embodiments, the film is a multi-layer film and has a thickness of 1.5 - 10.0 mil (37.5 ¨250 pm) or 2.5 ¨5.0 mil before foaming and a thickness of about 2.5 - 18.5 mil (62.5 ¨ 462.5 pm) or 3.0 ¨ 5.0 mil after foaming. In some embodiments, the core layer or film has a light transmission % of about 10 - 50% or about 20 ¨ 40 %.
[0019] In some embodiments, the film has a machine direction heat shrinkage of less than
2014/0322463) describes a uni-directionally oriented film comprised of a thermoplastic polyester and a polycarbonate. This type of film can be used for strapping of cartons, boxes, pallets, etc., and may be used as a weaving tape for woven bags, sacks, and containers.
Preferably, the polyester is a polyethylene terephthalate (PET) resin. Polycarbonate is blended into the PET film as a minority component to reduce the tendency of such PET unidirectionally oriented films from splitting along the machine direction axis and imparts some impact toughness.
Summary 100081 Disclosed herein is a novel polyolefin-based, monoaxially (or uni-axially) oriented film that can be suitable for strapping tape applications and/or other applications requiring high tear resistance. In some embodiments, the film can have a high resistance to cross-direction (or transverse direction, TD) tearing and can have a machine direction (MD) tensile strength of greater than about 75, 80, 85, or 90 lbs/inch width and less than about 130, 120, 115, 110 or 100 lbs/inch width. Preferably, the polyolefin can be a propylene-based polymer.
The tear resistance may be imparted by voiding of the film in which the voids interrupt or halt tear propagation through the film. Without being bound by any theory, it is believed that the voids provide termination points for crack/tear propagation and redirects the energy of the tear propagation from cross-wise (or transverse-wise) perpendicularly to the machine direction (along the direction of the monoaxial orientation) as depicted by Figure 1. It is also believed that the size and shape of these voids can play a role in the effectiveness of terminating tear propagation, with smaller, more ovoid or oblong voids being preferred. This can result in a film with very high cross-wise or transverse direction tear resistance without using machine-direction aligned and embedded fibers or filaments to impart transverse direction tear resistance as in the prior arts. In particular, the inventors have found that the disclosed films exhibit very good transverse tear resistance even if the film is nicked or cut on the edges of the film to initiate a transverse tear.
[0009] The described films may be simpler to produce than typical films and tapes. In some embodiments, the films can be produced without requiring the use -- or additional processing steps ¨ of embedding fibers or filaments. Because the film may not include any foreign matter such as glass fibers, the film can be more suitable for recycling scrap or spent material for other uses or as part of the production of new strapping tape.
[0010] In an embodiment, a single layer film may be extruded and mono-axially oriented in the machine direction. This single layer can be voided, which provides the transverse direction tear resistance. In additional multi-layer film embodiments, it is contemplated to coextrude one or more skin layers on one or both sides of a void-containing core or base layer which is mono-axially oriented in the machine direction. This voided core layer can provide the transverse direction tear resistance properties of the multi-layer film. Further embodiments include voiding of the coexruded skin layers or intermediate layers adjacent to the core layer as well. It can also be contemplated to void the skin layers for tear propagation resistance while leaving the core layer un-voided. However, the core layer can be the preferred layer for voiding as it represents the bulk of the film mass and the bulk of the voids to terminate crack/tear propagation. It can be preferred that the coextruded skin layers be un-voided to provide smoother outer surfaces more suitable for printing, laminating, coating, metallizing, or other process handling. Other embodiments of the disclosed films can include laminating the disclosed films to other substrates including, but not limited to: other unvoided polymeric films or articles, paper-containing substrates, cardboard-containing substrates, fabric textiles, non-woven textiles, meshes, tapes, etc.
[0011] Voiding of the disclosed films can be accomplished by several means, including but not limited to: 1) cavitating agents such as inorganic particles like CaCO3, Ti02, silica particles, glass micro-beads; 2) cavitating agents such as organic polymeric materials like polybutylene terephthalate, nylons, polycarbonates, polystyrenes, polymethlymethacrylate;
3) beta-nucleation of the propylene-based polymer; 4) chemical foaming agents; or 5) combinations of the above. A
preferred embodiment can be to use chemical foaming agents which provide relatively large voids or closed-cell cavities in which there is no physical particle residing within said void. Such an embodiment can help reduce the overall density of the voided film in comparison to a voided film using inorganic or polymeric cavitating agents wherein such cavitating agents add their intrinsic material density to the overall film density.
[0012] The film can also incorporate optional amounts of additives, including but not limited to: antiblock additives, slip additives, coloring agents/pigments, antistatic additives, UV-light absorbing or blocking additives, fire retardant additives.
[0013] Embodiments of a mono-axially oriented polyolefin film may comprise a core layer containing a plurality of voids. The film is oriented at least 4 times in the machine direction, and exhibits excellent tear resistance in the transverse direction.
[0014] In some embodiments, the film comprises at least one skin layer. The at least one skin layer may be voided or unvoided. In some embodiments, the core layer comprises a propylene-based polymer.
[0015] In some embodiments, the core layer comprises CaCO3, Ti02, silica particles, or glass micro-beads inorganic voiding particles. In some embodiments, the core layer comprises polymeric cavitating or voiding agents such as polybutylene terephthalate, nylon, polycarbonate, polystyrene, or polymethlymethacrylate. In some embodiments, the core layer comprises a propylene-based polymer and beta-nucleation of the propylene-based polymer to form a plurality of voids. In some embodiments, the core layer comprises a chemical foaming agent as the voiding agent.
[0016] In some embodiments, the film has a machine direction (MD) tensile strength of greater than about 75 lbsf/linear inch width, greater than about 85 lbsf/linear inch width, greater than about 95 lbsf/linear inch width, or greater than about 100 lbsf/linear inch width. In some embodiments, the film has a machine direction tensile strength of about 75-130 lbsf/linear inch width, about 85-130 lbsf/linear inch width, about 95-130 lbsf/linear inch width, or about 100-130 lbsf/linear inch width.
[0017] In some embodiments, the film is a mono-layer film and has a thickness of 1.5 - 10.0 mil (37.5 ¨ 250 pm) or 2.5 ¨ 5.0 mil before foaming and a thickness of about 2.5 - 18.5 mil (62.5 ¨ 462.5 pm) or 3.0 ¨ 5.0 mil after foaming.
[0018] In some embodiments, the film is a multi-layer film and has a thickness of 1.5 - 10.0 mil (37.5 ¨250 pm) or 2.5 ¨5.0 mil before foaming and a thickness of about 2.5 - 18.5 mil (62.5 ¨ 462.5 pm) or 3.0 ¨ 5.0 mil after foaming. In some embodiments, the core layer or film has a light transmission % of about 10 - 50% or about 20 ¨ 40 %.
[0019] In some embodiments, the film has a machine direction heat shrinkage of less than
8%, preferably less than 5%, and more preferably less than 2%.
[0020] An embodiment of a tape comprises a mono-axially oriented polyolefin film comprising a core layer containing a plurality of voids, wherein the film is oriented at least 4 times in the machine direction and exhibits excellent tear resistance in the transverse direction.
[0021] An embodiment of a method of making a mono-axially oriented polyolefin film comprises extruding a film comprising a layer, wherein the layer comprises a polyolefin (e.g., a propylene-based polyolefin) and a voiding agent, and orienting the film at least 4 times in the machine direction, wherein the film exhibits excellent tear resistance in the transverse direction.
[0022] In some embodiments, the method further comprises heat setting the extruded film.
In some embodiments, the method further comprises co-extruding at least one skin layer that may not include a voiding agent with the core layer. In some embodiments, the method forms a monolayer film.
[0023] In some embodiments, a mono-axially oriented polyolefin film is described that comprises a layer comprising a propylene-based polymer and a plurality of voids formed by a voiding agent, wherein the film is oriented at least 4 times in the machine direction.
[0024] The voiding agent can be a chemical foaming agent and can comprises 0.2-3 wt% of the layer. In some embodiments the density of the film is 0.60-0.89 g/cm3 and the average void size of the plurality of voids can be 5000-12000 p.m in width along the MD
axis. The standard deviation of the average void width can be 2000 p.m or less. In some embodiments, the film can have a thickness of 1.5-10 mil before foaming and a thickness of 2.5-18.5 mil after foaming. In some embodiments, the film comprises at least one skin layer and the skin layer can be unvoided.
100251 In some embodiments, the voiding agent comprises 1-10 wt% of the layer. In some embodiments, the voiding agent comprises CaCO3, Ti02, silica particles, or glass micro-beads inorganic void particles, polybutylene terephthalate, nylon, polycarbonate, polystyrene, or polymethlymethacrylate, or a beta-nucleation of the propylene-based polymer, [0026] In some embodiments, the film has a tensile strength of 80-120 lbs/inch width, a machine direction shrinkage of less than 2%, and/or a light transmission of 20-40%. In some embodiments, the film is a mono layer film.
[0027] In some embodiments, a tape is described that comprises the films disclosed herein.
Specifically, the tape can include a layer comprising a propylene-based polymer and a plurality of voids formed by a voiding agent, wherein the film is oriented at least 4 times in the machine direction.
[0028] It is understood that aspects and embodiments of the films described herein include "consisting" and/or "consisting essentially of' aspects and embodiments. For all methods, films, and other aspects described herein, the methods, films, and other aspects can either comprise the listed components or steps, or can "consist of' or "consist essentially of' the listed components or steps. When a method, film, and other aspect is described as "consisting essentially of' the listed components, method, film, and other aspect contains the components listed, and may contain other components which do not substantially affect the performance of the method, film, and other aspect, but either do not contain any other components which substantially affect the performance of the method, film, and other aspect other than those components expressly listed;
or do not contain a sufficient concentration or amount of the extra components to substantially affect the performance of the method, film, and other aspect. When a method is described as "consisting essentially of' the listed steps, the method contains the steps listed, and may contain other steps that do not substantially affect the outcome of the method, but the method does not contain any other steps which substantially affect the outcome of the method other than those steps expressly listed.
Brief Description of the Drawings [0029] Exemplary embodiments are described with reference to the accompanying Figures, in which:
[0030] FIG. 1 is an illustrative embodiment of a voided mono-axially oriented polyolefin film that exhibits excellent tear resistance.
[0031] FIG. 2 is an illustration of the void's dimensions within an embodiment of a mono-axially oriented polyolefin film that exhibits tear resistance.
Detailed Description [0032] Described are mono-axially oriented propylene-based films that exhibit excellent tear resistance and methods of making the same. In some embodiments, the films can be produced by blending a cavitating or foaming agent to produce a voided film which is mono-axially oriented.
The resulting film has surprisingly good tear resistance properties in the direction perpendicular to the orientation direction. Such a film lends itself well to applications such as, but not limited to: strapping tape for boxes, cartons, pallets, textile bales; corrugated cardboard reinforcements;
blister package board packaging; tape fabric; and carrying handles for cartons, boxes, and the like; or any applications requiring tear resistance properties. The disclosed films may be woven to produce a fabric for use in making sacks, bulk containers, carpet backing, signage, geo-textiles, and self-reinforced fabrics. The disclosed films may be tinted or colored to match consumer attributes for packaging or cartoning.
[0033] The film or layer may comprise, consist or consist essentially of the following materials: 1) a polyolefin or polyolefin blend (for example, a blend comprising one or more propylene homopolymers and copolymers); 2) a voiding agent ; and 3) optional additives, including but not limited to: antiblock additives, slip additives, coloring agents/pigments, antistatic additives, UV-light absorbing or blocking additives, fire retardant additives.
[0034] Suitable polyolefins can be propylene-based polymers such as isotactic crystalline propylene homopolymers and "mini-random" isotactic crystalline ethylene-propylene copolymers. "Mini-random" propylene homopolymers are those class of ethylene-propylene copolymers in which the ethylene content is fractional, i.e. less than 1 wt%, typically on the order of about 0.2-0.8 wt%, and preferably about 0.5-0.7 wt%, of the polymer. These crystalline isotactic polypropylenes are generally described as having an isotactic content of about 90% or greater as measured by C13 NMR. Suitable examples of crystalline propylene homopolymers are Total Petrochemicals 3271, 3274, and 3373HA; Phillips CH016, CH020, and CR035;
and Braskem FF018. These resins can also have melt flow rates of about 0.5 to 5 g/10min at 230 , a melting point of about 160 - 165 C, a crystallization temperature of about 108 ¨126 C, a heat of fusion of about 86 ¨ 110 J/g, a heat of crystallization of about 105 ¨ 111 J/g, and a density of about 0.90 ¨ 0.91. Higher isotactic content propylene homopolymers (i.e. "high crystalline"
homopolymers) may also be used. Suitable examples of these include those made by Total Petrochemicals 3270 and 3273 grades, Braskem grade HR020F3, and Phillipps 66 CH020XK.
These high crystalline polypropylenes typically have an isotactic content of 93% or greater as measured by C13 NMR spectra obtained in 1,2,4-trichlorobenzene solutions at 130 C. The %
percent isotactic can be obtained by the intensity of the isotactic methyl group at 21.7 ppm versus the total (isotactic and atactic) methyl groups from 22 to 19.4 ppm. These resins can also have melt flow rates of about 0.5 to 5 g/10min, a melting point of about 163 - 167 C, a crystallization temperature of about 108 ¨126 C, a heat of fusion of about 86¨ 110 J/g, a heat of crystallization of about 105 ¨ 111 J/g, and a density of about 0.90 ¨ 0.91.
[0035] Other suitable polyolefins can be propylene-containing copolymers such as ethylene-propylene copolymers, propylene-butene copolymers, ethylene-propylene-butene copolymers, including propylene-containing impact copolymers, and blends thereof. It can also be contemplated to blend propylene homopolymers, mini-random homopolymers, and copolymers as desired. Exemplary propylene-containing copolymers can include:
Total Petrochemicals Z9421 ethylene-propylene random copolymer elastomer of about 5.0 g/10min melt flow rate (MFR) at 230 C, melting point of about 120 C, density 0.89 g/cm3, and ethylene content of about 7 wt% of the polymer; Total Petrochemicals 8473 ethylene-propylene random copolymer of about 4.0 MFR at 230 C and ethylene content of about 4.5 wt% of the polymer;
Sumitomo Chemical SPX78R1 ethylene-propylene-butene random copolymer of about
[0020] An embodiment of a tape comprises a mono-axially oriented polyolefin film comprising a core layer containing a plurality of voids, wherein the film is oriented at least 4 times in the machine direction and exhibits excellent tear resistance in the transverse direction.
[0021] An embodiment of a method of making a mono-axially oriented polyolefin film comprises extruding a film comprising a layer, wherein the layer comprises a polyolefin (e.g., a propylene-based polyolefin) and a voiding agent, and orienting the film at least 4 times in the machine direction, wherein the film exhibits excellent tear resistance in the transverse direction.
[0022] In some embodiments, the method further comprises heat setting the extruded film.
In some embodiments, the method further comprises co-extruding at least one skin layer that may not include a voiding agent with the core layer. In some embodiments, the method forms a monolayer film.
[0023] In some embodiments, a mono-axially oriented polyolefin film is described that comprises a layer comprising a propylene-based polymer and a plurality of voids formed by a voiding agent, wherein the film is oriented at least 4 times in the machine direction.
[0024] The voiding agent can be a chemical foaming agent and can comprises 0.2-3 wt% of the layer. In some embodiments the density of the film is 0.60-0.89 g/cm3 and the average void size of the plurality of voids can be 5000-12000 p.m in width along the MD
axis. The standard deviation of the average void width can be 2000 p.m or less. In some embodiments, the film can have a thickness of 1.5-10 mil before foaming and a thickness of 2.5-18.5 mil after foaming. In some embodiments, the film comprises at least one skin layer and the skin layer can be unvoided.
100251 In some embodiments, the voiding agent comprises 1-10 wt% of the layer. In some embodiments, the voiding agent comprises CaCO3, Ti02, silica particles, or glass micro-beads inorganic void particles, polybutylene terephthalate, nylon, polycarbonate, polystyrene, or polymethlymethacrylate, or a beta-nucleation of the propylene-based polymer, [0026] In some embodiments, the film has a tensile strength of 80-120 lbs/inch width, a machine direction shrinkage of less than 2%, and/or a light transmission of 20-40%. In some embodiments, the film is a mono layer film.
[0027] In some embodiments, a tape is described that comprises the films disclosed herein.
Specifically, the tape can include a layer comprising a propylene-based polymer and a plurality of voids formed by a voiding agent, wherein the film is oriented at least 4 times in the machine direction.
[0028] It is understood that aspects and embodiments of the films described herein include "consisting" and/or "consisting essentially of' aspects and embodiments. For all methods, films, and other aspects described herein, the methods, films, and other aspects can either comprise the listed components or steps, or can "consist of' or "consist essentially of' the listed components or steps. When a method, film, and other aspect is described as "consisting essentially of' the listed components, method, film, and other aspect contains the components listed, and may contain other components which do not substantially affect the performance of the method, film, and other aspect, but either do not contain any other components which substantially affect the performance of the method, film, and other aspect other than those components expressly listed;
or do not contain a sufficient concentration or amount of the extra components to substantially affect the performance of the method, film, and other aspect. When a method is described as "consisting essentially of' the listed steps, the method contains the steps listed, and may contain other steps that do not substantially affect the outcome of the method, but the method does not contain any other steps which substantially affect the outcome of the method other than those steps expressly listed.
Brief Description of the Drawings [0029] Exemplary embodiments are described with reference to the accompanying Figures, in which:
[0030] FIG. 1 is an illustrative embodiment of a voided mono-axially oriented polyolefin film that exhibits excellent tear resistance.
[0031] FIG. 2 is an illustration of the void's dimensions within an embodiment of a mono-axially oriented polyolefin film that exhibits tear resistance.
Detailed Description [0032] Described are mono-axially oriented propylene-based films that exhibit excellent tear resistance and methods of making the same. In some embodiments, the films can be produced by blending a cavitating or foaming agent to produce a voided film which is mono-axially oriented.
The resulting film has surprisingly good tear resistance properties in the direction perpendicular to the orientation direction. Such a film lends itself well to applications such as, but not limited to: strapping tape for boxes, cartons, pallets, textile bales; corrugated cardboard reinforcements;
blister package board packaging; tape fabric; and carrying handles for cartons, boxes, and the like; or any applications requiring tear resistance properties. The disclosed films may be woven to produce a fabric for use in making sacks, bulk containers, carpet backing, signage, geo-textiles, and self-reinforced fabrics. The disclosed films may be tinted or colored to match consumer attributes for packaging or cartoning.
[0033] The film or layer may comprise, consist or consist essentially of the following materials: 1) a polyolefin or polyolefin blend (for example, a blend comprising one or more propylene homopolymers and copolymers); 2) a voiding agent ; and 3) optional additives, including but not limited to: antiblock additives, slip additives, coloring agents/pigments, antistatic additives, UV-light absorbing or blocking additives, fire retardant additives.
[0034] Suitable polyolefins can be propylene-based polymers such as isotactic crystalline propylene homopolymers and "mini-random" isotactic crystalline ethylene-propylene copolymers. "Mini-random" propylene homopolymers are those class of ethylene-propylene copolymers in which the ethylene content is fractional, i.e. less than 1 wt%, typically on the order of about 0.2-0.8 wt%, and preferably about 0.5-0.7 wt%, of the polymer. These crystalline isotactic polypropylenes are generally described as having an isotactic content of about 90% or greater as measured by C13 NMR. Suitable examples of crystalline propylene homopolymers are Total Petrochemicals 3271, 3274, and 3373HA; Phillips CH016, CH020, and CR035;
and Braskem FF018. These resins can also have melt flow rates of about 0.5 to 5 g/10min at 230 , a melting point of about 160 - 165 C, a crystallization temperature of about 108 ¨126 C, a heat of fusion of about 86 ¨ 110 J/g, a heat of crystallization of about 105 ¨ 111 J/g, and a density of about 0.90 ¨ 0.91. Higher isotactic content propylene homopolymers (i.e. "high crystalline"
homopolymers) may also be used. Suitable examples of these include those made by Total Petrochemicals 3270 and 3273 grades, Braskem grade HR020F3, and Phillipps 66 CH020XK.
These high crystalline polypropylenes typically have an isotactic content of 93% or greater as measured by C13 NMR spectra obtained in 1,2,4-trichlorobenzene solutions at 130 C. The %
percent isotactic can be obtained by the intensity of the isotactic methyl group at 21.7 ppm versus the total (isotactic and atactic) methyl groups from 22 to 19.4 ppm. These resins can also have melt flow rates of about 0.5 to 5 g/10min, a melting point of about 163 - 167 C, a crystallization temperature of about 108 ¨126 C, a heat of fusion of about 86¨ 110 J/g, a heat of crystallization of about 105 ¨ 111 J/g, and a density of about 0.90 ¨ 0.91.
[0035] Other suitable polyolefins can be propylene-containing copolymers such as ethylene-propylene copolymers, propylene-butene copolymers, ethylene-propylene-butene copolymers, including propylene-containing impact copolymers, and blends thereof. It can also be contemplated to blend propylene homopolymers, mini-random homopolymers, and copolymers as desired. Exemplary propylene-containing copolymers can include:
Total Petrochemicals Z9421 ethylene-propylene random copolymer elastomer of about 5.0 g/10min melt flow rate (MFR) at 230 C, melting point of about 120 C, density 0.89 g/cm3, and ethylene content of about 7 wt% of the polymer; Total Petrochemicals 8473 ethylene-propylene random copolymer of about 4.0 MFR at 230 C and ethylene content of about 4.5 wt% of the polymer;
Sumitomo Chemical SPX78R1 ethylene-propylene-butene random copolymer of about
9.5 g/10min MFR at 230 C, ethylene content of about 1.5 wt%, and butene content of about 16 wt%
of the polymer; or ExxonMobil Chemical VistamaxxTM ethylene-propylene random copolymer elastomers such as grade 3980 FL with an MFR of about 8.3 g/10min at 230 C, Vicat softening point of about 80 C, melting point of about 79 C, density of about 0.879 g/cm3, and ethylene content of about 8.5 wt%. Other suitable propylene-based copolymers and elastomers may be contemplated including but not limited to: metallocene-catalyzed thermoplastic elastomers like ExxonMobil's VistamaxxTM 3000 grade, which is an ethylene-propylene elastomer of about 11 wt% ethylene content, 8 g/10min MFR at 230 C, density of 0.871 g/cm3, Tg of -20 to -30 C, and Vicat softening point of 64 C; or ethylene-propylene alpha-olefin copolymer plastomers of Dow Chemical's VersifyTM grades, such as grade 3300, which is an ethylene-propylene plastomer of about 12 wt% ethylene content, 8 g/10 min MFR at 230 C, density of 0.866 g/cm3, Tg of -28 C, and Vicat softening point of 29 C; and Mitsui Chemicals TafmerTm grades XM7070 and XM7080 metallocene-catalyzed propylene-butene random elastomers of about 22 and 26 wt%
butene content, respectively. The Mitsui Tafmer grades are characterized by a melting point of 75 C and 83 C, respectively; a Vicat softening point of 67 C and 74 C, respectively; a density of 0.883-0.885 g/cm3; a Tg of about -15 C; a melt flow rate at 230 C of 7.0 g/10 minutes; and a molecular weight of 190,000-192,000 g/mol. Exemplary impact copolymers can be an isotactic ethylene-propylene copolymer with an ethylene-propylene rubber content of about 10-30 wt% of the polymer wherein the ethylene content of the rubber is about 10-80 wt% of the rubber.
Typically, the impact copolymer is manufactured in two reactors. In the first reactor, propylene homopolymer is produced and it is conveyed to the second reactor that also contains a high concentration of ethylene. The ethylene, in conjunction with the residual propylene left over from the first reactor, copolymerizes to form an ethylene-propylene rubber.
The resultant product has two distinct phases: a continuous rigid propylene homopolymer matrix and a finely dispersed phase of ethylene-propylene rubber particles. The rubber content that is typically used is in the 10-30 wt% range depending on the desired end-use properties. It is this mixture of two phases ¨ the propylene homopolymer matrix and the dispersed phase of ethylene-propylene rubber ¨ that provides the impact resistance and toughening properties that impact copolymers are known for. Ethylene-propylene impact copolymers are distinctly different from conventional ethylene-propylene random copolymers which are typically polymerized in a single reactor, generally have a lower ethylene content (typically 0.5 wt% to 6 wt%) wherein the ethylene groups are randomly inserted by a catalyst along the polypropylene backbone chain, and do not comprise an ethylene-propylene rubber content. A suitable example of ethylene-propylene impact copolymer for the disclosed films is Total Petrochemical's 5571. Total Petrochemicals 5571 has a melt flow rate of about 7 g/10 minutes at 230 C, a melting point of about 160-165 C, a Vicat softening point of about 148 C, and a density of about 0.905 g/cm3.
Another example of ethylene-propylene impact copolymer can be Total Petrochemical's 4180 with a melt flow rate of about 0.7 g/10 minutes at 230 C, a melting point of about 160-165 C, a Vicat softening point of about 150 C, and a density of about 0.905 g/cm3. Other suitable ethylene-propylene impact copolymers can be Sunoco Chemical's TI-4015-F2 with a melt flow rate of 1.6 g/10minutes at 230 C and a density of about 0.901 g/cm3 and ExxonMobil Chemical's PP7033E2 with a melt flow rate of about 8 g/10 minutes at at 230 C and a density of about 0.9 g/cm3.
[0036] Isotactic propylene homopolymers, copolymers, and blends thereof are particularly preferred for the disclosed films. Other polyolefins that could also be considered, however, are ethylene homopolymers such as high density polyethylene, medium density polyethylene, low density polyethylene, and linear low density polyethylenes.
These ethylene homopolymers may also be blended with ethylene copolymers, propylene copolymers, and/or propylene homopolymers. Among these types, high density polyethylenes (HDPE) are preferred, such as Total Petrochemical's HDPE 9658 (density 0.958 g/cc, MI 0.64 g/10 min), or Total Petrochemical HDPE 9458 (density 0.958 g/cc, MI 0.45 g/10 min), or Total Petrochemical HDPE 9260 (density 0.960 g/cc, MI 2.0 g/10 min).
[0037] In addition, these isotactic crystalline propylene-based resins may also include additives such as antiblocking agents and/or slip agents. An amount of inorganic antiblocking agent may be optionally added up to 10,000 ppm to the film layer(s) as desired for film-handling purposes, winding, antiblocking properties, and control of coefficient of friction. Preferably about 300-5000 ppm, and more preferably about 300 ¨ 1000 ppm, of antiblock may be added.
Suitable antiblock agents comprise those such as inorganic silicas, sodium calcium aluminosilicates, crosslinked silicone polymers such as polymethylsilsesquioxane, and polymethylmethacrylate spheres. Typical useful particle sizes of these antiblocks range from 1 ¨
12 um, preferably in the range of 2-6 um. Slip agents such as fatty amides and/or silicone oils can also be optionally employed in either or both film layers, either with or without the inorganic antiblocking additives, to aid further with controlling coefficient of friction and web handling issues. Such slip agents are typically migratory and bloom to the surface of the film. Suitable types of fatty amides are those such as stearamide or erucamide and similar types, in amounts of 100-5000 ppm of the layer. Preferably, erucamide can be used at 500-1000 ppm of the layer. A
suitable silicone oil that can be used is a low molecular weight oil of 350 centistokes which blooms to the surface readily at a loading of 400-600 ppm of either or both layers. Antiblock and slip agents can be conveniently used in the form of masterbatches at desired loadings for economy and using desired carrier resins.
[0038] The formation of a plurality of closed cell voids within the disclosed films can be critical to imparting the tear resistance of said films. Preferably, the main layer (also known as the base layer or core layer) can be the voided layer of a mono-layer or multi-layer embodiment as this layer is typically the thickest layer and comprises the bulk mass of the film. However, in multi-layer film embodiments, the coextruded "skin" layers adjacent to the core layer (either on one side of the core layer or on both sides of the core layer) could be the voided layer(s) in place of the core layer or both the skin layers and core layer could be voided.
Voids may be formed within the respective film layer through cavitation by using inorganic or organic cavitating agents well known in the art. Such inorganic cavitating agents can be: calcium carbonate (CaCO3), titanium dioxide (Ti02), silica or silicate particles, glass micro-beads, or other inorganic particulates and/or minerals. Preferred inorganic cavitating agents can be calcium carbonate particles due to its popularity as well as economy. Particle diameter sizes of the inorganic cavitating agents can be in the range of about 0.1 ¨2.0 pm. Typical loadings of the inorganic cavitating agents can be about 1 ¨ 10 wt% of the layer, preferably about 2-5 wt%. Organic cavitating agents can be used as well, such as polybutylene terephthalate, polycarbonate, nylon, polymethylmethacrylate, polystyrene. Typically, such polymeric cavitating agents have a higher Tg than the propylene-based bulk resin of the disclosed films. Typical loadings of organic cavitating agents can be about 1-10 wt% of the layer.
[0039] After die-casting the film and quenching, voids or cavities can be formed by orientation of the film in the machine direction. Without being bound by any theory, such stretching or orientation at certain processing temperatures can form stress points about the cavitating agent particles, resulting in a plurality of closed cell voids or cavities. These voids will typically contain the cavitating agent particle within the void.
[0040] A preferred method to produce the voided films disclosed herein can be to use a chemical foaming agent (CFA) as the cavitating or voiding agent. Such chemical foaming agents degrade under the polymer processing extrusion temperatures, thereby liberating gases within the polymer melt. Upon exit from the melt pipe and die, the entrapped gases can expand, thereby forming a foamed film layer with a plurality of closed cell voids. The decomposition of the CFA
can be either exothermic or endothermic. Exothermic CFAs release energy during decomposition and can include hydrazines and azo compounds. Such compounds can be characteristically yellowish in color and should be handled with care to avoid skin irritation.
Endothermic CFAs consume energy during decomposition, thus requiring continuous energy input during the full reaction time and can be usually based on bicarbonate and citric acid powders. Such derivatives are also used as food additives, are safer to handle, and can be preferred for this reason. In the case of using CFAs to form the voided film layer, such voids will typically not contain a solid particle within the void or cavity in contrast to using inorganic or polymeric cavitating agents. The amount of CFA to use in the core layer of the voided film disclosed herein can be in the range of about 0.2 ¨ 3.0 wt% of the layer, preferably 0.3 ¨ 1.0 wt%, and more preferably 0.4 ¨ 0.6 wt%. Such chemical foaming agents may be dry-blended as-is or as a masterbatch with the polyolefin resin pellets prior to melt extrusion.
[0041] Suitable chemical foaming agents may be obtained from Bergan International under their FoamazolTM brand name, in particular, grade FoamazolTM 63. FoamazolTM 63 is an endothermic-type CFA, with a melting point of about 110 - 130 C and bulk density of about 42 lb/ft3 (0.673 g/cm3). Another suitable endothermic chemical foaming agent may be obtained from Clariant under their HydrocerolTM brand name, in particular, grade masterbatch, with a melting point of about 104 - 115 C and masterbatch specific gravity of about 0.91 ¨ 0.97.
[0042] The films disclosed herein can be made by dry-blending the component resins and materials (e.g. propylene-based polymer blends, chemical foaming agent, antiblock additives, and other optional additives such a colorants) and melt-extruded them through a die at extrusion temperatures of about 390-465 F (199-240 C). The die temperature can be about (146-196 C). The films can also be cast on a chill drum at about 130 F (54 C) and a casting speed of about 38.5 fpm (12 mpm). In addition, the films can also be oriented in the machine direction (MD) via a series of heated and differentially sped rolls at about 270-280 F (132-138 C) for the preheat section, and about 205 F (96 C) for the stretching section. The films can be heat-set or annealed in the final zones of the MD orientation section at about 280 F (138 C) to reduce internal stresses, minimize heat shrinkage of the film, and maintain a thermally dimensionally stable mono-axially oriented film. The machine direction mono-axial orientation ratio can be about 4.0- 7.0: 1.0, meaning that the film was stretched in the machine direction at about 4 - 7 times its original dimension at casting; about 5.0-7.0: 1.0; or about 6.0-7.0: 1Ø
Preferably, machine direction orientation can be about 6.5:1Ø Production linespeed after MD
orientation at 6.5:1.0 can be about 250 fpm (76 mpm). Typical total thickness of the disclosed films after orientation (and foaming) can range from about 2.0 to 10.0 mil (200 ¨ 1000G or 50 ¨
250 pm) or about 3.0 ¨ 5.0 mil in thickness. Density of the foamed film can range from about 0.60 ¨ 0.89 g/cm3, preferred about 0.60 ¨ 0.80 g/cm3, and more preferably about 0.64 ¨ 0.78 g/cm3. Average void sizes can range from about 5000 ¨ 12,000 pm in width (along the MD
axis), preferably greater than 6000 pm width, and more preferably 8000 pm or greater; and about 10 ¨ 100 pm in height as depicted in Figure 2. Uniformity of the voids within the film is desirable and can be characterized by measuring the standard deviation of the voids' average width in a representative sample. The preferred standard deviation of the average void width can be about 2000 pm or less, and preferably, 1500 pm or less.
[0043] The films disclosed herein may also be discharge-treated on one or both sides of the film using methods well-known in the art such as corona or flame or atmospheric plasma. In addition, other methods after MD orientation can be used in order to raise the wetting tension of the film on one or both sides of the film. Preferably, the film can be treated on both sides.
Furthermore, the mono-oriented polypropylene-based (MOPP) film can be wound in roll form.
[0044] The following is a list of materials that were used in the Examples provided herein:
[0045] Materials:
= Total Petrochemicals 3274 isotactic crystalline propylene homopolymer:
melt flow rate 1.5 g/10min at 230 C, melting point 163 C, and density 0.905 g/cm3 = Braskem TI4015F propylene-based impact copolymer: melt flow rate 1.6 g/10minutes at 230 C and density 0.901 g/cm3 = Total Petrochemicals 3576XHD isotactic crystalline propylene homopolymer, containing ca. 5000ppm Silton0 JC-30 sodium calcium aluminum silicate antiblock particles of nominal 3.0 diameter: melt flow rate 8.0 g/10min at 230 C and density 0.905 g/cm3 = Bergan International FoamazolTM 63 chemical foaming agent masterbatch:
melting point 110-130 C and bulk density 42 lb/ft3 = Clariant Hydrocerole PEAN698596 chemical foaming agent masterbatch = (Optional) Ampacet Blue 463163: blue pigment masterbatch in propylene homopolymer carrier resin.
Example and Comparative Examples:
Example 1: A single layer mono-axially oriented film (MOPP) was made using a ca.
1.5 m-wide mono-axial orientation film-making process with a blend comprising about 44.1 wt%
Total 3274, about 49.0 wt% Braskem TI4015F, about 4.9 wt% Total 3276XHD, about 1.0 wt%
FoamazolTM 63 masterbatch; and about 1.0 wt% of Ampacet Blue masterbatch (to impart an blue tint to the film for aesthetic purposes). A voided film was produced per the processing conditions described previously. Specifically, the film was dry-blended and melt-extruded through a die at extrusion temperatures of about 390-465 F (199-240 C); die temperature was about 295 F (146 C); cast on a chill drum at about 130 F (54 C) and a casting speed of about 38.5 fpm (12 mpm), and orientation in the machine direction (MD) via a series of heated and differentially sped rolls at about 270-280 F (132-138 C) for the preheat section, and about 205 F
(96 C) for the stretching section. The film was heat-set or annealed in the final zones of the MD
orientation section at about 280 F (138 C) to reduce internal stresses and minimize heat shrinkage of the film and maintain a thermally dimensionally stable mono-axially oriented film.
The machine direction mono-axial orientation ratio was about 6.5:1.0, meaning that the film was stretched in the machine direction at about 6.5 times its original dimension at casting.
Production linespeed after MD orientation was about 250 fpm (76 mpm).
[0047] The thickness of the film was about 2.7 mils (67.5 um) thickness of extruded polyweight prior to foaming. After foaming/void formation and mono-axial orientation, the finished film thickness was about 5.0 mils (125 um) thickness. Density of the film prior to foaming/voiding was ca. 0.905 g/cm3 and after foaming /voiding the film density was ca. 0.60 g/cm3.
100481 Example 2: A film was made similar to Example 1 except that the extruded polyweight thickness of the film prior to foaming was about 2.8 mils (70 um).
After foaming and mono-axial orientation, the finished film thickness was about 5.2 mils (130 um).
[0049] Example 3: A film was made similar to Example 1 except that Clariant was used at about 2.0 wt% of the film. The amount of Total 3274 was about 43.6 wt%; the amount of Braskem TI4015F was about 48.5 wt%; the amount of Total 3576XHD was about 4.9 wt%; and about 1.0 wt% Ampacet Blue masterbatch was used. The extruded polyweight gauge prior to foaming/voiding was about 2.7 mils (70 um). After foaming/void formulation, the finished film thickness was greater than 6.0 mils (125-150 um).
[0050] Comparative Example 1: A film was made similar to Example 1 except that no chemical foaming agent was used. The composition was about 44.6 wt% Total 3274; about 49.5 wt% Braskem T14015F; about 4.9 wt% Total 3576XHD; and about 1.0 wt% Ampacet Blue masterbatch. The finished film thickness after MD orientation was about 2.7 mils (67.5 um).
[0051] The MOPP film roll Examples were then tested for optics (gloss and light transmission), wetting tension, COF, elongation, tensile strength, and tear resistance.
[0052] The following Tables IA and 1B illustrates the properties of these Examples:
Sample TD Tear MD Heat MD MD/TD MD Appearance Resistance Shrinkage Tensile Modulus Elongation Rating % (Thermal Strength kpsi (1=best; Dimensional 'Winch width 3=poor) Stability) Ex. 1 1 <2.0 95 30.7 24 Good Ex. 2 1 <2.0 100 31.3 24 Good Ex. 3 1 NT^ NP NT" NP Poor CEx. 1 3 <2.0 160 210 25 Good Sample Light Gloss Wetting COF
Transmission (60 ) Tension static/dynamic ok Dyne-cmicm2 In/Out* In/Out* Out/Out* In/In*
Ex. 1 30.8 39 / 32 42 / 42 0.49 / 0.41 0.57 /
0.48 Ex. 2 29.7 42 / 33 42 / 42 0.48 / 0.38 0.56 /
0.46 Ex. 3 NT^ NT^ NT^ NT^ NT^
CEx. 1 29.0 82/83 42/42 0.67/0.59 0.68/0.60 A Not tested due to poor quality of film appearance.
* -Out" refers to the side of the film that was in contact with the air side during casting; "In"
refers to the side of the film that was in contact with the casting drum side during casting.
[0053] As Tables 1A and 1B show, Comparative Example 1 (CEx 1) was a un-foamed/un-voided control film. Appearance was very good and consistent with excellent MD
tensile properties and low heat shrinkage. Gloss values of CEx. 1 were higher than that of the Examples due to a smoother surface since CEx. 1 was unvoided. Tensile properties were also higher than the Examples due to being an unvoided film. However, when a film sheet of CEx.
1 was torn by hand at a notch made in the transverse direction side of the film, tear resistance in the transverse direction (orthogonal to the orientation direction in the machine direction) was very poor in that tearing was initiated and propagated transversely across through the film very easily with little effort. Tear resistance property was rated 3 ("poor") where a rating of 1 (-excellent", no or little transverse tear through) or 2 ("good", some transverse tear through) is desirable. CExl's transverse tear resistance was considered to be poor.
[0054] Example 1 (Ex 1) shows a film with about 1 wt% of the chemical foaming agent FoamazolTM 63 to void/foam/cavitate the film layer. Appearance was acceptable and MD tensile properties were good at 95 lb/in and 24% MD elongation. MD heat shrinkage was also very good at less than 2% shrinkage. This film showed excellent tear resistance in the transverse direction and was rated a 1.
[0055] Example 2 (Ex 2) showed a film that was similar to Ex. 1 but was extruded to be slightly thicker than Ex. 1 at nominal 5.2 mil (130 p.m) vs. 5.0 mil (125 vim), respectively.
Appearance was acceptable and MD tensile properties were very good at 100 lb/in and 24% MD
elongation. MD heat shrinkage was also very good at less than 2% shrinkage.
This film showed excellent tear resistance in the transverse direction and was rated a 1.
[0056] Example 3 (Ex 3) showed a film that used a different chemical foaming agent, 2 wt%
of Hydrocerol0 PEAN698596 instead of 1 wt% FoamazolTM 63. Unfortunately, void sizes using this foaming agent were very large, causing very poor appearance on the film's surface. Process modifications were made (MDO stretch temperatures) as well as different loadings of the foaming agent (0.5 wt%, 0.8 wt%, 1.0 wt%, and 2 wt%) in an attempt to control degree of foaming and void formation. Foaming could only be consistently done at the 2 wt% level (the lower levels exhibited little or no foaming). In this Example, the film was considered to be "over-foamed" with voids that were considered to be too large (bursting through outer surfaces of the film) and appearance was very poor. Cavitated or foamed thickness was also greater than desired, in excess of 6 mils (150 pm). For this reason, most of the standard testing was not conducted since no suitable or consistent enough film was made of this example. However, transverse tear resistance was tested and was found to be excellent despite the large void sizes and was rated a 1.
[0057] Examples 4 to 9 [0058] Additional Examples 4 - 9 were made similar to Example 1 but with varying amounts of FoamazolTM 63 of about 0.4 and 0.6 wt% of the core layer and machine direction orientation (MDX) of about 6.2:1.0 and 6.7:1Ø The extrusion temperature melt pipe was set at ca. 425 F
(218 C) and die temperature was about 375 F (190.5 C). The extruded polyweight gauge of these single layer film Examples prior to foaming/voiding was about 2.85 mils (71.25 lam). After foaming/void formulation, the finished film thickness ranged from 3.0 -4.0 mils (75-100 [tm).
Table 2A summarizes the formulations and conditions for these Examples.
Table 2A
Example FoamazolTM Total Braskem Total Ampacet MDX Foamed Film wt% 3274 TI4015 3576XHD 463163 Thickness wt% wt% wt% wt% mils (pm) 4 0.4 44.6 49.0 5.0 1.0 6.2 3.0 (75) 0.6 44.4 49.0 5.0 1.0 6.2 3.8(95) 6 0.4 44.6 49.0 5.0 1.0 6.7 3.0 (75) 7 0.6 44.4 49.0 5.0 1.0 6.7 3.2 (80) 8 0.6 44.4 49.0 5.0 1.0 6.2 3.5 (87.5) 9 0.6 44.4 49.0 5.0 1.0 6.7 4.0 (100) 100591 Tables 2B and 2C summarize some of the properties tested for Examples 4-9.
Average void width (measured along the longitudinal dimension), void uniformity (standard deviation of average void width), voided film density, tear resistance rating, and both machine direction (MD) and transverse direction (TD) tensile properties were tested.
Table 2B
Example Void Size Void Film Density Tear Resistance pm Uniformity g/cm3 Rating pm 1-3 (1 best;
3=poor) 4 6050 2093 0.838 3 8866 1522 0.642 1 6 1414 NT 0.882 3 7 10,662 1837 0.782 2 8 9189 1571 0.733 2 9 8185 371 0.637 1 Table 2C
Example MD Tensile MD Modulus MD TD Tensile TD
Modulus TD
Strength kpsi Elongation Strength kpsi Elongation lbf/in % Ibf/in %
4 118.0 39.3 30.4 9.1 3.0 9.1 5 79.8 21.0 15.3 6.4 1.7 7.9 6 126.1 42.0 30.6 11.5 3.8 4.6 7 100.0 31.3 19.5 9.0 2.8 10.1 8 99.7 28.5 21.1 7.1 2.0 7.8 9 88.8 22.2 14.6 5.6 1.4 6.5 100601 In Table 2B, Examples 5, 7, 8, and 9 showed the best tear resistance rating property, with ratings of at least a "2", indicating good resistance to transverse direction tear propagation.
Examples 4 and 6 showed the poorest tear resistance property, with a rating of "3", indicating no or little resistance to transverse direction tear propagation. It is noted that the void sizes and uniformity for Examples 4 and 6 are significantly lower and worse, respectively, than that of Examples 5, 7 ¨ 9. It is also noted that the voided film density of Examples 4 and 6 are significantly higher than that of Examples 5, 7 ¨ 9. Without being bound by any theory, there appears to be a correlation between void size/uniformity, voided film density, and tear resistance property. Larger-sized voids and more uniform voids appear to be more favorable for tear resistance; lower voided film density also appears to correlate to more favorable tear resistance property. The exemplary films with good tear resistance appear to have larger and more uniform voids ¨ and since they are more voided, these exemplary films will have a lower density.
Poor tear resistance disclosed films will have smaller (or no) voids; and consequently, their film density will be higher. Based on the results of Table 2B, void sizes of greater than about 6000 pm in width appear to be preferred for good transverse tear resistance properties; preferably, the void sizes should be about 8000 pm or more. In some embodiments, the void sizes are about 6000-12,000 pm or about 8000-12000 pm in width. Void uniformity should be less than about 2000 pm, and preferably about 1500 pm or less. Similarly, film density should be less than about 0.83 g/cm3, preferably less than 0.80, and more preferably, less than 0.70.
[0061] MD tensile strengths for Examples 4-9 were good overall, in particular Examples 4, 6,7, and 8. Similarly for MD modulus and elongation, Examples 4, 6, 7, and 8 showed the best values of this Example set. However, Examples 4 and 6 were poorest for tear resistance.
Examples 7 and 8 showed a good balance of good tear resistance and good tensile properties.
Test Methods [0062] The various properties in the above examples were measured by the following methods:
[0063] A) Tear Resistance: Tear resistance was tested qualitatively by notching a piece of test film on one edge of the transverse direction (or cross-width) side; and tearing by hand at the notch to initiate the tear. The notch was made parallel to the transverse direction of the test film with a pair of scissors with notch length approximately 1/4 inch (ca. 6 mm) and the tear propagated along the transverse direction. The tear was initiated from the notch by hand and observation made as to the ease with which the tear could be propagated across the transverse width of the film. The preferred observation for good tear resistance property was: 1) tearing could not be initiated and could not be propagated transversely and tear propagation transferred to the machine direction only; 2) tearing was difficult to initiate and difficult to propagate transversely and tear propagation transferred to the machine direction only;
3) tearing was easily initiated and easily propagated in the transverse direction. Ratings were as follows:
1 = No tear propagation or initiation in transverse direction 2 = Some or difficulty in propagating tear in transverse direction 3 = Easy to initiate and propagate tear in transverse direction [0064] B) Light Transmission of a single sheet of film was measured substantially in accordance with ASTM D1003. In some embodiments, the film has a light transmission of about
of the polymer; or ExxonMobil Chemical VistamaxxTM ethylene-propylene random copolymer elastomers such as grade 3980 FL with an MFR of about 8.3 g/10min at 230 C, Vicat softening point of about 80 C, melting point of about 79 C, density of about 0.879 g/cm3, and ethylene content of about 8.5 wt%. Other suitable propylene-based copolymers and elastomers may be contemplated including but not limited to: metallocene-catalyzed thermoplastic elastomers like ExxonMobil's VistamaxxTM 3000 grade, which is an ethylene-propylene elastomer of about 11 wt% ethylene content, 8 g/10min MFR at 230 C, density of 0.871 g/cm3, Tg of -20 to -30 C, and Vicat softening point of 64 C; or ethylene-propylene alpha-olefin copolymer plastomers of Dow Chemical's VersifyTM grades, such as grade 3300, which is an ethylene-propylene plastomer of about 12 wt% ethylene content, 8 g/10 min MFR at 230 C, density of 0.866 g/cm3, Tg of -28 C, and Vicat softening point of 29 C; and Mitsui Chemicals TafmerTm grades XM7070 and XM7080 metallocene-catalyzed propylene-butene random elastomers of about 22 and 26 wt%
butene content, respectively. The Mitsui Tafmer grades are characterized by a melting point of 75 C and 83 C, respectively; a Vicat softening point of 67 C and 74 C, respectively; a density of 0.883-0.885 g/cm3; a Tg of about -15 C; a melt flow rate at 230 C of 7.0 g/10 minutes; and a molecular weight of 190,000-192,000 g/mol. Exemplary impact copolymers can be an isotactic ethylene-propylene copolymer with an ethylene-propylene rubber content of about 10-30 wt% of the polymer wherein the ethylene content of the rubber is about 10-80 wt% of the rubber.
Typically, the impact copolymer is manufactured in two reactors. In the first reactor, propylene homopolymer is produced and it is conveyed to the second reactor that also contains a high concentration of ethylene. The ethylene, in conjunction with the residual propylene left over from the first reactor, copolymerizes to form an ethylene-propylene rubber.
The resultant product has two distinct phases: a continuous rigid propylene homopolymer matrix and a finely dispersed phase of ethylene-propylene rubber particles. The rubber content that is typically used is in the 10-30 wt% range depending on the desired end-use properties. It is this mixture of two phases ¨ the propylene homopolymer matrix and the dispersed phase of ethylene-propylene rubber ¨ that provides the impact resistance and toughening properties that impact copolymers are known for. Ethylene-propylene impact copolymers are distinctly different from conventional ethylene-propylene random copolymers which are typically polymerized in a single reactor, generally have a lower ethylene content (typically 0.5 wt% to 6 wt%) wherein the ethylene groups are randomly inserted by a catalyst along the polypropylene backbone chain, and do not comprise an ethylene-propylene rubber content. A suitable example of ethylene-propylene impact copolymer for the disclosed films is Total Petrochemical's 5571. Total Petrochemicals 5571 has a melt flow rate of about 7 g/10 minutes at 230 C, a melting point of about 160-165 C, a Vicat softening point of about 148 C, and a density of about 0.905 g/cm3.
Another example of ethylene-propylene impact copolymer can be Total Petrochemical's 4180 with a melt flow rate of about 0.7 g/10 minutes at 230 C, a melting point of about 160-165 C, a Vicat softening point of about 150 C, and a density of about 0.905 g/cm3. Other suitable ethylene-propylene impact copolymers can be Sunoco Chemical's TI-4015-F2 with a melt flow rate of 1.6 g/10minutes at 230 C and a density of about 0.901 g/cm3 and ExxonMobil Chemical's PP7033E2 with a melt flow rate of about 8 g/10 minutes at at 230 C and a density of about 0.9 g/cm3.
[0036] Isotactic propylene homopolymers, copolymers, and blends thereof are particularly preferred for the disclosed films. Other polyolefins that could also be considered, however, are ethylene homopolymers such as high density polyethylene, medium density polyethylene, low density polyethylene, and linear low density polyethylenes.
These ethylene homopolymers may also be blended with ethylene copolymers, propylene copolymers, and/or propylene homopolymers. Among these types, high density polyethylenes (HDPE) are preferred, such as Total Petrochemical's HDPE 9658 (density 0.958 g/cc, MI 0.64 g/10 min), or Total Petrochemical HDPE 9458 (density 0.958 g/cc, MI 0.45 g/10 min), or Total Petrochemical HDPE 9260 (density 0.960 g/cc, MI 2.0 g/10 min).
[0037] In addition, these isotactic crystalline propylene-based resins may also include additives such as antiblocking agents and/or slip agents. An amount of inorganic antiblocking agent may be optionally added up to 10,000 ppm to the film layer(s) as desired for film-handling purposes, winding, antiblocking properties, and control of coefficient of friction. Preferably about 300-5000 ppm, and more preferably about 300 ¨ 1000 ppm, of antiblock may be added.
Suitable antiblock agents comprise those such as inorganic silicas, sodium calcium aluminosilicates, crosslinked silicone polymers such as polymethylsilsesquioxane, and polymethylmethacrylate spheres. Typical useful particle sizes of these antiblocks range from 1 ¨
12 um, preferably in the range of 2-6 um. Slip agents such as fatty amides and/or silicone oils can also be optionally employed in either or both film layers, either with or without the inorganic antiblocking additives, to aid further with controlling coefficient of friction and web handling issues. Such slip agents are typically migratory and bloom to the surface of the film. Suitable types of fatty amides are those such as stearamide or erucamide and similar types, in amounts of 100-5000 ppm of the layer. Preferably, erucamide can be used at 500-1000 ppm of the layer. A
suitable silicone oil that can be used is a low molecular weight oil of 350 centistokes which blooms to the surface readily at a loading of 400-600 ppm of either or both layers. Antiblock and slip agents can be conveniently used in the form of masterbatches at desired loadings for economy and using desired carrier resins.
[0038] The formation of a plurality of closed cell voids within the disclosed films can be critical to imparting the tear resistance of said films. Preferably, the main layer (also known as the base layer or core layer) can be the voided layer of a mono-layer or multi-layer embodiment as this layer is typically the thickest layer and comprises the bulk mass of the film. However, in multi-layer film embodiments, the coextruded "skin" layers adjacent to the core layer (either on one side of the core layer or on both sides of the core layer) could be the voided layer(s) in place of the core layer or both the skin layers and core layer could be voided.
Voids may be formed within the respective film layer through cavitation by using inorganic or organic cavitating agents well known in the art. Such inorganic cavitating agents can be: calcium carbonate (CaCO3), titanium dioxide (Ti02), silica or silicate particles, glass micro-beads, or other inorganic particulates and/or minerals. Preferred inorganic cavitating agents can be calcium carbonate particles due to its popularity as well as economy. Particle diameter sizes of the inorganic cavitating agents can be in the range of about 0.1 ¨2.0 pm. Typical loadings of the inorganic cavitating agents can be about 1 ¨ 10 wt% of the layer, preferably about 2-5 wt%. Organic cavitating agents can be used as well, such as polybutylene terephthalate, polycarbonate, nylon, polymethylmethacrylate, polystyrene. Typically, such polymeric cavitating agents have a higher Tg than the propylene-based bulk resin of the disclosed films. Typical loadings of organic cavitating agents can be about 1-10 wt% of the layer.
[0039] After die-casting the film and quenching, voids or cavities can be formed by orientation of the film in the machine direction. Without being bound by any theory, such stretching or orientation at certain processing temperatures can form stress points about the cavitating agent particles, resulting in a plurality of closed cell voids or cavities. These voids will typically contain the cavitating agent particle within the void.
[0040] A preferred method to produce the voided films disclosed herein can be to use a chemical foaming agent (CFA) as the cavitating or voiding agent. Such chemical foaming agents degrade under the polymer processing extrusion temperatures, thereby liberating gases within the polymer melt. Upon exit from the melt pipe and die, the entrapped gases can expand, thereby forming a foamed film layer with a plurality of closed cell voids. The decomposition of the CFA
can be either exothermic or endothermic. Exothermic CFAs release energy during decomposition and can include hydrazines and azo compounds. Such compounds can be characteristically yellowish in color and should be handled with care to avoid skin irritation.
Endothermic CFAs consume energy during decomposition, thus requiring continuous energy input during the full reaction time and can be usually based on bicarbonate and citric acid powders. Such derivatives are also used as food additives, are safer to handle, and can be preferred for this reason. In the case of using CFAs to form the voided film layer, such voids will typically not contain a solid particle within the void or cavity in contrast to using inorganic or polymeric cavitating agents. The amount of CFA to use in the core layer of the voided film disclosed herein can be in the range of about 0.2 ¨ 3.0 wt% of the layer, preferably 0.3 ¨ 1.0 wt%, and more preferably 0.4 ¨ 0.6 wt%. Such chemical foaming agents may be dry-blended as-is or as a masterbatch with the polyolefin resin pellets prior to melt extrusion.
[0041] Suitable chemical foaming agents may be obtained from Bergan International under their FoamazolTM brand name, in particular, grade FoamazolTM 63. FoamazolTM 63 is an endothermic-type CFA, with a melting point of about 110 - 130 C and bulk density of about 42 lb/ft3 (0.673 g/cm3). Another suitable endothermic chemical foaming agent may be obtained from Clariant under their HydrocerolTM brand name, in particular, grade masterbatch, with a melting point of about 104 - 115 C and masterbatch specific gravity of about 0.91 ¨ 0.97.
[0042] The films disclosed herein can be made by dry-blending the component resins and materials (e.g. propylene-based polymer blends, chemical foaming agent, antiblock additives, and other optional additives such a colorants) and melt-extruded them through a die at extrusion temperatures of about 390-465 F (199-240 C). The die temperature can be about (146-196 C). The films can also be cast on a chill drum at about 130 F (54 C) and a casting speed of about 38.5 fpm (12 mpm). In addition, the films can also be oriented in the machine direction (MD) via a series of heated and differentially sped rolls at about 270-280 F (132-138 C) for the preheat section, and about 205 F (96 C) for the stretching section. The films can be heat-set or annealed in the final zones of the MD orientation section at about 280 F (138 C) to reduce internal stresses, minimize heat shrinkage of the film, and maintain a thermally dimensionally stable mono-axially oriented film. The machine direction mono-axial orientation ratio can be about 4.0- 7.0: 1.0, meaning that the film was stretched in the machine direction at about 4 - 7 times its original dimension at casting; about 5.0-7.0: 1.0; or about 6.0-7.0: 1Ø
Preferably, machine direction orientation can be about 6.5:1Ø Production linespeed after MD
orientation at 6.5:1.0 can be about 250 fpm (76 mpm). Typical total thickness of the disclosed films after orientation (and foaming) can range from about 2.0 to 10.0 mil (200 ¨ 1000G or 50 ¨
250 pm) or about 3.0 ¨ 5.0 mil in thickness. Density of the foamed film can range from about 0.60 ¨ 0.89 g/cm3, preferred about 0.60 ¨ 0.80 g/cm3, and more preferably about 0.64 ¨ 0.78 g/cm3. Average void sizes can range from about 5000 ¨ 12,000 pm in width (along the MD
axis), preferably greater than 6000 pm width, and more preferably 8000 pm or greater; and about 10 ¨ 100 pm in height as depicted in Figure 2. Uniformity of the voids within the film is desirable and can be characterized by measuring the standard deviation of the voids' average width in a representative sample. The preferred standard deviation of the average void width can be about 2000 pm or less, and preferably, 1500 pm or less.
[0043] The films disclosed herein may also be discharge-treated on one or both sides of the film using methods well-known in the art such as corona or flame or atmospheric plasma. In addition, other methods after MD orientation can be used in order to raise the wetting tension of the film on one or both sides of the film. Preferably, the film can be treated on both sides.
Furthermore, the mono-oriented polypropylene-based (MOPP) film can be wound in roll form.
[0044] The following is a list of materials that were used in the Examples provided herein:
[0045] Materials:
= Total Petrochemicals 3274 isotactic crystalline propylene homopolymer:
melt flow rate 1.5 g/10min at 230 C, melting point 163 C, and density 0.905 g/cm3 = Braskem TI4015F propylene-based impact copolymer: melt flow rate 1.6 g/10minutes at 230 C and density 0.901 g/cm3 = Total Petrochemicals 3576XHD isotactic crystalline propylene homopolymer, containing ca. 5000ppm Silton0 JC-30 sodium calcium aluminum silicate antiblock particles of nominal 3.0 diameter: melt flow rate 8.0 g/10min at 230 C and density 0.905 g/cm3 = Bergan International FoamazolTM 63 chemical foaming agent masterbatch:
melting point 110-130 C and bulk density 42 lb/ft3 = Clariant Hydrocerole PEAN698596 chemical foaming agent masterbatch = (Optional) Ampacet Blue 463163: blue pigment masterbatch in propylene homopolymer carrier resin.
Example and Comparative Examples:
Example 1: A single layer mono-axially oriented film (MOPP) was made using a ca.
1.5 m-wide mono-axial orientation film-making process with a blend comprising about 44.1 wt%
Total 3274, about 49.0 wt% Braskem TI4015F, about 4.9 wt% Total 3276XHD, about 1.0 wt%
FoamazolTM 63 masterbatch; and about 1.0 wt% of Ampacet Blue masterbatch (to impart an blue tint to the film for aesthetic purposes). A voided film was produced per the processing conditions described previously. Specifically, the film was dry-blended and melt-extruded through a die at extrusion temperatures of about 390-465 F (199-240 C); die temperature was about 295 F (146 C); cast on a chill drum at about 130 F (54 C) and a casting speed of about 38.5 fpm (12 mpm), and orientation in the machine direction (MD) via a series of heated and differentially sped rolls at about 270-280 F (132-138 C) for the preheat section, and about 205 F
(96 C) for the stretching section. The film was heat-set or annealed in the final zones of the MD
orientation section at about 280 F (138 C) to reduce internal stresses and minimize heat shrinkage of the film and maintain a thermally dimensionally stable mono-axially oriented film.
The machine direction mono-axial orientation ratio was about 6.5:1.0, meaning that the film was stretched in the machine direction at about 6.5 times its original dimension at casting.
Production linespeed after MD orientation was about 250 fpm (76 mpm).
[0047] The thickness of the film was about 2.7 mils (67.5 um) thickness of extruded polyweight prior to foaming. After foaming/void formation and mono-axial orientation, the finished film thickness was about 5.0 mils (125 um) thickness. Density of the film prior to foaming/voiding was ca. 0.905 g/cm3 and after foaming /voiding the film density was ca. 0.60 g/cm3.
100481 Example 2: A film was made similar to Example 1 except that the extruded polyweight thickness of the film prior to foaming was about 2.8 mils (70 um).
After foaming and mono-axial orientation, the finished film thickness was about 5.2 mils (130 um).
[0049] Example 3: A film was made similar to Example 1 except that Clariant was used at about 2.0 wt% of the film. The amount of Total 3274 was about 43.6 wt%; the amount of Braskem TI4015F was about 48.5 wt%; the amount of Total 3576XHD was about 4.9 wt%; and about 1.0 wt% Ampacet Blue masterbatch was used. The extruded polyweight gauge prior to foaming/voiding was about 2.7 mils (70 um). After foaming/void formulation, the finished film thickness was greater than 6.0 mils (125-150 um).
[0050] Comparative Example 1: A film was made similar to Example 1 except that no chemical foaming agent was used. The composition was about 44.6 wt% Total 3274; about 49.5 wt% Braskem T14015F; about 4.9 wt% Total 3576XHD; and about 1.0 wt% Ampacet Blue masterbatch. The finished film thickness after MD orientation was about 2.7 mils (67.5 um).
[0051] The MOPP film roll Examples were then tested for optics (gloss and light transmission), wetting tension, COF, elongation, tensile strength, and tear resistance.
[0052] The following Tables IA and 1B illustrates the properties of these Examples:
Sample TD Tear MD Heat MD MD/TD MD Appearance Resistance Shrinkage Tensile Modulus Elongation Rating % (Thermal Strength kpsi (1=best; Dimensional 'Winch width 3=poor) Stability) Ex. 1 1 <2.0 95 30.7 24 Good Ex. 2 1 <2.0 100 31.3 24 Good Ex. 3 1 NT^ NP NT" NP Poor CEx. 1 3 <2.0 160 210 25 Good Sample Light Gloss Wetting COF
Transmission (60 ) Tension static/dynamic ok Dyne-cmicm2 In/Out* In/Out* Out/Out* In/In*
Ex. 1 30.8 39 / 32 42 / 42 0.49 / 0.41 0.57 /
0.48 Ex. 2 29.7 42 / 33 42 / 42 0.48 / 0.38 0.56 /
0.46 Ex. 3 NT^ NT^ NT^ NT^ NT^
CEx. 1 29.0 82/83 42/42 0.67/0.59 0.68/0.60 A Not tested due to poor quality of film appearance.
* -Out" refers to the side of the film that was in contact with the air side during casting; "In"
refers to the side of the film that was in contact with the casting drum side during casting.
[0053] As Tables 1A and 1B show, Comparative Example 1 (CEx 1) was a un-foamed/un-voided control film. Appearance was very good and consistent with excellent MD
tensile properties and low heat shrinkage. Gloss values of CEx. 1 were higher than that of the Examples due to a smoother surface since CEx. 1 was unvoided. Tensile properties were also higher than the Examples due to being an unvoided film. However, when a film sheet of CEx.
1 was torn by hand at a notch made in the transverse direction side of the film, tear resistance in the transverse direction (orthogonal to the orientation direction in the machine direction) was very poor in that tearing was initiated and propagated transversely across through the film very easily with little effort. Tear resistance property was rated 3 ("poor") where a rating of 1 (-excellent", no or little transverse tear through) or 2 ("good", some transverse tear through) is desirable. CExl's transverse tear resistance was considered to be poor.
[0054] Example 1 (Ex 1) shows a film with about 1 wt% of the chemical foaming agent FoamazolTM 63 to void/foam/cavitate the film layer. Appearance was acceptable and MD tensile properties were good at 95 lb/in and 24% MD elongation. MD heat shrinkage was also very good at less than 2% shrinkage. This film showed excellent tear resistance in the transverse direction and was rated a 1.
[0055] Example 2 (Ex 2) showed a film that was similar to Ex. 1 but was extruded to be slightly thicker than Ex. 1 at nominal 5.2 mil (130 p.m) vs. 5.0 mil (125 vim), respectively.
Appearance was acceptable and MD tensile properties were very good at 100 lb/in and 24% MD
elongation. MD heat shrinkage was also very good at less than 2% shrinkage.
This film showed excellent tear resistance in the transverse direction and was rated a 1.
[0056] Example 3 (Ex 3) showed a film that used a different chemical foaming agent, 2 wt%
of Hydrocerol0 PEAN698596 instead of 1 wt% FoamazolTM 63. Unfortunately, void sizes using this foaming agent were very large, causing very poor appearance on the film's surface. Process modifications were made (MDO stretch temperatures) as well as different loadings of the foaming agent (0.5 wt%, 0.8 wt%, 1.0 wt%, and 2 wt%) in an attempt to control degree of foaming and void formation. Foaming could only be consistently done at the 2 wt% level (the lower levels exhibited little or no foaming). In this Example, the film was considered to be "over-foamed" with voids that were considered to be too large (bursting through outer surfaces of the film) and appearance was very poor. Cavitated or foamed thickness was also greater than desired, in excess of 6 mils (150 pm). For this reason, most of the standard testing was not conducted since no suitable or consistent enough film was made of this example. However, transverse tear resistance was tested and was found to be excellent despite the large void sizes and was rated a 1.
[0057] Examples 4 to 9 [0058] Additional Examples 4 - 9 were made similar to Example 1 but with varying amounts of FoamazolTM 63 of about 0.4 and 0.6 wt% of the core layer and machine direction orientation (MDX) of about 6.2:1.0 and 6.7:1Ø The extrusion temperature melt pipe was set at ca. 425 F
(218 C) and die temperature was about 375 F (190.5 C). The extruded polyweight gauge of these single layer film Examples prior to foaming/voiding was about 2.85 mils (71.25 lam). After foaming/void formulation, the finished film thickness ranged from 3.0 -4.0 mils (75-100 [tm).
Table 2A summarizes the formulations and conditions for these Examples.
Table 2A
Example FoamazolTM Total Braskem Total Ampacet MDX Foamed Film wt% 3274 TI4015 3576XHD 463163 Thickness wt% wt% wt% wt% mils (pm) 4 0.4 44.6 49.0 5.0 1.0 6.2 3.0 (75) 0.6 44.4 49.0 5.0 1.0 6.2 3.8(95) 6 0.4 44.6 49.0 5.0 1.0 6.7 3.0 (75) 7 0.6 44.4 49.0 5.0 1.0 6.7 3.2 (80) 8 0.6 44.4 49.0 5.0 1.0 6.2 3.5 (87.5) 9 0.6 44.4 49.0 5.0 1.0 6.7 4.0 (100) 100591 Tables 2B and 2C summarize some of the properties tested for Examples 4-9.
Average void width (measured along the longitudinal dimension), void uniformity (standard deviation of average void width), voided film density, tear resistance rating, and both machine direction (MD) and transverse direction (TD) tensile properties were tested.
Table 2B
Example Void Size Void Film Density Tear Resistance pm Uniformity g/cm3 Rating pm 1-3 (1 best;
3=poor) 4 6050 2093 0.838 3 8866 1522 0.642 1 6 1414 NT 0.882 3 7 10,662 1837 0.782 2 8 9189 1571 0.733 2 9 8185 371 0.637 1 Table 2C
Example MD Tensile MD Modulus MD TD Tensile TD
Modulus TD
Strength kpsi Elongation Strength kpsi Elongation lbf/in % Ibf/in %
4 118.0 39.3 30.4 9.1 3.0 9.1 5 79.8 21.0 15.3 6.4 1.7 7.9 6 126.1 42.0 30.6 11.5 3.8 4.6 7 100.0 31.3 19.5 9.0 2.8 10.1 8 99.7 28.5 21.1 7.1 2.0 7.8 9 88.8 22.2 14.6 5.6 1.4 6.5 100601 In Table 2B, Examples 5, 7, 8, and 9 showed the best tear resistance rating property, with ratings of at least a "2", indicating good resistance to transverse direction tear propagation.
Examples 4 and 6 showed the poorest tear resistance property, with a rating of "3", indicating no or little resistance to transverse direction tear propagation. It is noted that the void sizes and uniformity for Examples 4 and 6 are significantly lower and worse, respectively, than that of Examples 5, 7 ¨ 9. It is also noted that the voided film density of Examples 4 and 6 are significantly higher than that of Examples 5, 7 ¨ 9. Without being bound by any theory, there appears to be a correlation between void size/uniformity, voided film density, and tear resistance property. Larger-sized voids and more uniform voids appear to be more favorable for tear resistance; lower voided film density also appears to correlate to more favorable tear resistance property. The exemplary films with good tear resistance appear to have larger and more uniform voids ¨ and since they are more voided, these exemplary films will have a lower density.
Poor tear resistance disclosed films will have smaller (or no) voids; and consequently, their film density will be higher. Based on the results of Table 2B, void sizes of greater than about 6000 pm in width appear to be preferred for good transverse tear resistance properties; preferably, the void sizes should be about 8000 pm or more. In some embodiments, the void sizes are about 6000-12,000 pm or about 8000-12000 pm in width. Void uniformity should be less than about 2000 pm, and preferably about 1500 pm or less. Similarly, film density should be less than about 0.83 g/cm3, preferably less than 0.80, and more preferably, less than 0.70.
[0061] MD tensile strengths for Examples 4-9 were good overall, in particular Examples 4, 6,7, and 8. Similarly for MD modulus and elongation, Examples 4, 6, 7, and 8 showed the best values of this Example set. However, Examples 4 and 6 were poorest for tear resistance.
Examples 7 and 8 showed a good balance of good tear resistance and good tensile properties.
Test Methods [0062] The various properties in the above examples were measured by the following methods:
[0063] A) Tear Resistance: Tear resistance was tested qualitatively by notching a piece of test film on one edge of the transverse direction (or cross-width) side; and tearing by hand at the notch to initiate the tear. The notch was made parallel to the transverse direction of the test film with a pair of scissors with notch length approximately 1/4 inch (ca. 6 mm) and the tear propagated along the transverse direction. The tear was initiated from the notch by hand and observation made as to the ease with which the tear could be propagated across the transverse width of the film. The preferred observation for good tear resistance property was: 1) tearing could not be initiated and could not be propagated transversely and tear propagation transferred to the machine direction only; 2) tearing was difficult to initiate and difficult to propagate transversely and tear propagation transferred to the machine direction only;
3) tearing was easily initiated and easily propagated in the transverse direction. Ratings were as follows:
1 = No tear propagation or initiation in transverse direction 2 = Some or difficulty in propagating tear in transverse direction 3 = Easy to initiate and propagate tear in transverse direction [0064] B) Light Transmission of a single sheet of film was measured substantially in accordance with ASTM D1003. In some embodiments, the film has a light transmission of about
10-50%, 20-40%, or about 20-30%.
[0065] C) Gloss was conducted on both sides of a single sheet of film and was measured substantially in accordance with ASTM D2457. In some embodiments, the film has a gloss of 20 or greater.
[0066] D) COF was conducted on both sides of a single sheet of film and was measured substantially in accordance with ASTM D1894. In some embodiments, the film has a COF of about 0.2 -1.0 or about 0.3-0.7.
[0067] E) Tensile Properties: Modulus, Tensile Strength, Elongation was conducted in the MD and/or TD direction of the film substantially in accordance with ASTM D882.
In some embodiments, the film can have an MD and/or TD tensile strength of at least about 75 lb/in or at least about 90 lb/in. In some embodiments, the film can have an MD and/or TD
modulus of at least about 20 kpsi or at least about 30 kpsi. In some embodiments, the film can have an MD
and/or TD elongation of at least about 10% or of at least about 15%.
[0068] F) Thermal Dimensional Stability (i.e., Heat Shrinkage) was tested by cutting a strip of the film 1 inch-wide in the transverse direction by 50 inches long in the MD direction. This strip was then immersed in 100 C water for 10 minutes. After this immersion time, the film strip was removed, dried with paper towels, and measured again along the MD
direction. The percent change in dimension from the original MD length was recorded.
[0069] G) Wetting Tension was measured on the discharge-treated side(s) of the film substantially in accordance with ASTM 2578-67. In some embodiments, the film can have a wetting tension of at least about 36 dynes. In some embodiments, the film can have a wetting tension of about 39-42 dynes.
[0070] H) Appearance: Appearance of the film was observed qualitatively. In essence, exemplary films that were consistent in appearance were considered acceptable;
films that were very inconsistent in appearance were considered to be poor.
[0071] I) Void Size and Void Uniformity: Cross-sections of 3 representative film samples per Example were taken parallel to the MD direction of the film (orthoganally to the transverse direction of the film) and examined via a digital optical microscope (Keyance model VHX).
Magnification was 30x and the samples were backlit with polarized light to make the voids more easily observable. Imaging software integrated with the Keyance digital microscope was used to measure the number of voids and void sizes in the field of view. The average size and standard deviation were calculated and reported. Void size is defined as the average dimensional width of the voids and void uniformity is defined as the standard deviation of the average void widths.
[0001] J) Film Density: Density of the film was calculated by taking a stack of 10 sheets (letter paper size e.g. 8.5 inches by 11 inches) of film and cutting them via a die or template of area 33.69 cm2 and weighing said cut sheets on an analytical scale. The 10 sheets are also measured for thickness using a flat-head micrometer to get an average thickness of the film. The measured weight and thickness is then used in a calculation to obtain density:
Weight (g) = Density (g/cm3) [0072] Thickness (cm) x area (cm') [0073]
This application discloses several numerical ranges. The numerical ranges disclosed inherently support any range or value within the disclosed numerical ranges even though a precise range limitation is not stated verbatim in the specification because the disclosed subject matter can be practiced throughout the disclosed numerical ranges.
100741 The above description is presented to enable a person skilled in the art to make and use the disclosed subject matter, and is provided in the context of a particular application and its requirements. Various modifications to the preferred embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments and applications without departing from the scope of the claimed invention. Thus, the claimed invention is not intended to be limited to the embodiments shown, but is to be accorded the widest scope consistent with the principles and features disclosed herein.
[0065] C) Gloss was conducted on both sides of a single sheet of film and was measured substantially in accordance with ASTM D2457. In some embodiments, the film has a gloss of 20 or greater.
[0066] D) COF was conducted on both sides of a single sheet of film and was measured substantially in accordance with ASTM D1894. In some embodiments, the film has a COF of about 0.2 -1.0 or about 0.3-0.7.
[0067] E) Tensile Properties: Modulus, Tensile Strength, Elongation was conducted in the MD and/or TD direction of the film substantially in accordance with ASTM D882.
In some embodiments, the film can have an MD and/or TD tensile strength of at least about 75 lb/in or at least about 90 lb/in. In some embodiments, the film can have an MD and/or TD
modulus of at least about 20 kpsi or at least about 30 kpsi. In some embodiments, the film can have an MD
and/or TD elongation of at least about 10% or of at least about 15%.
[0068] F) Thermal Dimensional Stability (i.e., Heat Shrinkage) was tested by cutting a strip of the film 1 inch-wide in the transverse direction by 50 inches long in the MD direction. This strip was then immersed in 100 C water for 10 minutes. After this immersion time, the film strip was removed, dried with paper towels, and measured again along the MD
direction. The percent change in dimension from the original MD length was recorded.
[0069] G) Wetting Tension was measured on the discharge-treated side(s) of the film substantially in accordance with ASTM 2578-67. In some embodiments, the film can have a wetting tension of at least about 36 dynes. In some embodiments, the film can have a wetting tension of about 39-42 dynes.
[0070] H) Appearance: Appearance of the film was observed qualitatively. In essence, exemplary films that were consistent in appearance were considered acceptable;
films that were very inconsistent in appearance were considered to be poor.
[0071] I) Void Size and Void Uniformity: Cross-sections of 3 representative film samples per Example were taken parallel to the MD direction of the film (orthoganally to the transverse direction of the film) and examined via a digital optical microscope (Keyance model VHX).
Magnification was 30x and the samples were backlit with polarized light to make the voids more easily observable. Imaging software integrated with the Keyance digital microscope was used to measure the number of voids and void sizes in the field of view. The average size and standard deviation were calculated and reported. Void size is defined as the average dimensional width of the voids and void uniformity is defined as the standard deviation of the average void widths.
[0001] J) Film Density: Density of the film was calculated by taking a stack of 10 sheets (letter paper size e.g. 8.5 inches by 11 inches) of film and cutting them via a die or template of area 33.69 cm2 and weighing said cut sheets on an analytical scale. The 10 sheets are also measured for thickness using a flat-head micrometer to get an average thickness of the film. The measured weight and thickness is then used in a calculation to obtain density:
Weight (g) = Density (g/cm3) [0072] Thickness (cm) x area (cm') [0073]
This application discloses several numerical ranges. The numerical ranges disclosed inherently support any range or value within the disclosed numerical ranges even though a precise range limitation is not stated verbatim in the specification because the disclosed subject matter can be practiced throughout the disclosed numerical ranges.
100741 The above description is presented to enable a person skilled in the art to make and use the disclosed subject matter, and is provided in the context of a particular application and its requirements. Various modifications to the preferred embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments and applications without departing from the scope of the claimed invention. Thus, the claimed invention is not intended to be limited to the embodiments shown, but is to be accorded the widest scope consistent with the principles and features disclosed herein.
Claims (38)
1. A mono-axially oriented polyolefin film comprising:
a layer comprising a propylene-based polymer and a plurality of voids formed by a voiding agent, wherein the film is oriented at least 4 times in the machine direction.
a layer comprising a propylene-based polymer and a plurality of voids formed by a voiding agent, wherein the film is oriented at least 4 times in the machine direction.
2. The mono-axially oriented film of claim 1, wherein the voiding agent comprises a chemical foaming agent.
3. The mono-axially oriented film of claim 2, wherein the chemical foaming agent comprises 0.2-3 wt.% of the layer.
4. The mono-axially oriented film of claim 2 or 3, wherein the density of the film is 0.60-0.89 g/cm3.
5. The mono-axially oriented film of claim 2, 3, or 4, wherein the average void size of the plurality of voids is 5000 ¨ 12,000 nm in width along the MD axis.
6. The mono-axially oriented film of claim 5, wherein the standard deviation of the average void width is 2000 p.m or less.
7. The mono-axially oriented film of any one of claims 2 to 6, wherein the film has a thickness of 1.5-10 mil before foaming.
8. The mono-axially oriented film of any one of claims 2 to 7, wherein the film has a thickness of 2.5-18.5 mil after foaming.
9. The mono-axially oriented film of any one of claims 1 to 8, further comprising at least one skin layer.
10. The mono-axially oriented film of claim 9, wherein the at least one skin layer is unvoided.
11. The monoaxially oriented film of any one of claims 1 to 10, wherein the voiding agent comprises 1-10 wt.% of the layer.
12. The mono-axially oriented film of claim 11, wherein the voiding agent comprises CaCO3, TiO2, silica particles, or glass micro-beads inorganic void particles.
13. The mono-axially oriented film of claim 11, wherein the voiding agent comprises polybutylene terephthalate, nylon, polycarbonate, polystyrene, or polymethlymethacrylate.
14. The mono-axially oriented film of claim 11, wherein the voiding agent comprises a beta-nucleation of the propylene-based polymer.
15. The mono-axially oriented film of any one of claims 1 to 14, wherein the film has a tensile strength of 80-120 lbs/inch width.
16. The mono-axially oriented film of any one of claims 1 to 15, wherein the film has a machine direction heat shrinkage of less than 2%.
17. The mono-axially oriented film of any one of claims 1 to 16, wherein the film has a light transmission of 20-40%.
18. The mono-axially oriented film of any one of claims 1 to 8, wherein the film is a monolayer film.
19. A method of making a mono-axially oriented polyolefin film comprising:
extruding a film comprising a layer, wherein the layer comprises a propylene-based polyolefin and a voiding agent;
orienting the film at least 4 times in the machine direction.
extruding a film comprising a layer, wherein the layer comprises a propylene-based polyolefin and a voiding agent;
orienting the film at least 4 times in the machine direction.
20. The method of claim 19, further comprising heat setting the extruded film.
21. The method of claim 19 or 20, further comprising co-extruding at least one skin layer with the layer.
22. The method of claim 21, wherein the at least one skin layer does not include a voiding agent.
23. The method of claim 19, wherein the film is a monolayer film.
24. The method of any one of claims 19 to 23, wherein the voiding agent comprises a chemical foaming agent.
25. The method of claim 24, wherein the chemical foaming agent comprises 0.2-3 wt.% of the layer.
26. The method of claim 24 or 25, wherein the density of the film is 0.60-0.89 g/cm3.
27. The method of claim 24, 25, or 26, wherein the average void size of the plurality of voids is 5000 ¨ 12,000 µm in width along the MD axis.
28. The method of claim 27, wherein the standard deviation of the average void width is 2000 um or less.
29. The method of any one of claims 24 to 28, wherein the film has a thickness of 1.5-mil before foaming.
30. The method of any one of claims 24 to 29, wherein the film has a thickness of 2.5-18.5 mil after foaming.
31. The method of any one of claims 19 to 30, wherein the voiding agent comprises 1-10 wt.% of the layer.
32. The method of claim 31, wherein the voiding agent comprises CaCO3, TiO2, silica particles, or glass micro-beads inorganic void particles.
33. The method of claim 31, wherein the voiding agent comprises polybutylene terephthalate, nylon, polycarbonate, polystyrene, or polymethlymethacrylate.
34. The method of claim 31, wherein the voiding agent comprises a beta-nucleation of the propylene-based polymer.
35. The method of any one of claims 19 to 34, wherein the film has a tensile strength of 80-120 lbs/inch width.
36. The method of any one of claims 19 to 35, wherein the film has a machine direction heat shrinkage of less than 2%.
37. The method of any one of claims 19 to 36, wherein the film has a light transmission of 20-40%.
38. A tape comprising:
a layer comprising a propylene-based polymer and a plurality of voids formed by a voiding agent, wherein the film is oriented at least 4 times in the machine direction.
a layer comprising a propylene-based polymer and a plurality of voids formed by a voiding agent, wherein the film is oriented at least 4 times in the machine direction.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CA2961692A CA2961692A1 (en) | 2017-03-20 | 2017-03-20 | Tear resistant mono-axially oriented propylene-based film |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CA2961692A CA2961692A1 (en) | 2017-03-20 | 2017-03-20 | Tear resistant mono-axially oriented propylene-based film |
Publications (1)
Publication Number | Publication Date |
---|---|
CA2961692A1 true CA2961692A1 (en) | 2018-09-20 |
Family
ID=63580122
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
CA2961692A Abandoned CA2961692A1 (en) | 2017-03-20 | 2017-03-20 | Tear resistant mono-axially oriented propylene-based film |
Country Status (1)
Country | Link |
---|---|
CA (1) | CA2961692A1 (en) |
-
2017
- 2017-03-20 CA CA2961692A patent/CA2961692A1/en not_active Abandoned
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US11518861B2 (en) | Tear resistant mono-axially oriented propylene-based film | |
US6444301B1 (en) | Labels | |
JP4890064B2 (en) | Biaxially oriented polypropylene film and packaging bag | |
KR20190111975A (en) | Biaxially oriented polypropylene-based film | |
KR101380101B1 (en) | Heat shrinkable polyolefin film and process for producing the same | |
JPWO2018180164A1 (en) | Biaxially oriented polypropylene film | |
JP2019019197A (en) | Polypropylene vertically uniaxially stretched film and film laminate | |
JP5151017B2 (en) | Laminated polypropylene film | |
JP4670477B2 (en) | Laminated polyolefin foam film | |
JP2007045046A (en) | Highly concealable heat sealable polyolefin foamed film | |
CA2961692A1 (en) | Tear resistant mono-axially oriented propylene-based film | |
WO2008006199A1 (en) | Pigmented film with improved aesthetic properties | |
JP5545627B2 (en) | Polyolefin thin film multilayer shrink film | |
JP2007045047A (en) | Heat-sealable polyolefinic foamed film | |
JP4904672B2 (en) | Heat-sealable polyolefin foam film | |
WO2021200593A1 (en) | Polyolefin-based resin film, and laminate using same | |
JP6994398B2 (en) | Polypropylene film | |
AU2015341089B2 (en) | Transparent polyolefin film | |
JPH09262945A (en) | Polypropylene laminated film and its manufacture | |
WO2014173544A1 (en) | Multilayer film with capability for linear tear propagation | |
JP2004345185A (en) | Polyolefinic foamed film | |
JP4305734B2 (en) | Polyolefin foam film | |
EP4332153A1 (en) | Polypropylene-based heat shrinkable film | |
JP4591260B2 (en) | Heat-sealable polyolefin foam film with good gloss | |
JP4591259B2 (en) | Heat-sealable polyolefin foam film with good concealment |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
FZDE | Discontinued |
Effective date: 20220922 |
|
FZDE | Discontinued |
Effective date: 20220922 |