WO1999001279A1 - Multilayered metallocene stretch wrap films - Google Patents
Multilayered metallocene stretch wrap films Download PDFInfo
- Publication number
- WO1999001279A1 WO1999001279A1 PCT/US1998/012221 US9812221W WO9901279A1 WO 1999001279 A1 WO1999001279 A1 WO 1999001279A1 US 9812221 W US9812221 W US 9812221W WO 9901279 A1 WO9901279 A1 WO 9901279A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- wrap film
- stretch wrap
- cling
- layer
- film
- Prior art date
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B27/00—Layered products comprising a layer of synthetic resin
- B32B27/32—Layered products comprising a layer of synthetic resin comprising polyolefins
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B27/00—Layered products comprising a layer of synthetic resin
- B32B27/06—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material
- B32B27/08—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B27/00—Layered products comprising a layer of synthetic resin
- B32B27/30—Layered products comprising a layer of synthetic resin comprising vinyl (co)polymers; comprising acrylic (co)polymers
- B32B27/308—Layered products comprising a layer of synthetic resin comprising vinyl (co)polymers; comprising acrylic (co)polymers comprising acrylic (co)polymers
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B27/00—Layered products comprising a layer of synthetic resin
- B32B27/32—Layered products comprising a layer of synthetic resin comprising polyolefins
- B32B27/327—Layered products comprising a layer of synthetic resin comprising polyolefins comprising polyolefins obtained by a metallocene or single-site catalyst
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2250/00—Layers arrangement
- B32B2250/24—All layers being polymeric
- B32B2250/242—All polymers belonging to those covered by group B32B27/32
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2250/00—Layers arrangement
- B32B2250/24—All layers being polymeric
- B32B2250/246—All polymers belonging to those covered by groups B32B27/32 and B32B27/30
-
- 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
- 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
- B32B2323/00—Polyalkenes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2323/00—Polyalkenes
- B32B2323/04—Polyethylene
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2323/00—Polyalkenes
- B32B2323/04—Polyethylene
- B32B2323/046—LDPE, i.e. low density polyethylene
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2323/00—Polyalkenes
- B32B2323/10—Polypropylene
-
- 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
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/31504—Composite [nonstructural laminate]
- Y10T428/31855—Of addition polymer from unsaturated monomers
- Y10T428/31909—Next to second addition polymer from unsaturated monomers
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/31504—Composite [nonstructural laminate]
- Y10T428/31855—Of addition polymer from unsaturated monomers
- Y10T428/31909—Next to second addition polymer from unsaturated monomers
- Y10T428/31913—Monoolefin polymer
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/31504—Composite [nonstructural laminate]
- Y10T428/31855—Of addition polymer from unsaturated monomers
- Y10T428/31909—Next to second addition polymer from unsaturated monomers
- Y10T428/31928—Ester, halide or nitrile of addition polymer
Definitions
- the present invention is directed to stretch wrap films and methods for their use.
- the present invention is directed to stretch wrap films having excellent maximum stretch, moderate holding force, superior puncture resistance, high total energy dart drop, high cling force and overall strength.
- thermoplastic stretch wrap films for the overwrap packaging of goods, and in particular, the unitizing of palleted loads is a significant commercially important application of polymer film, including generically, polyethylene.
- Overwrapping a plurality of articles to provide a unitized load can be achieved by a variety of techniques. In one procedure, the load to be wrapped is positioned on a platform, or turntable, which is made to rotate and in so doing, to take up stretch wrap film supplied from a continuous roll. Braking tension is applied to the film roll so that the film is continuously subjected to a stretching or tensioning force as it wraps around the rotating load in overlapping layers.
- the stretch wrap film is supplied from a vertically arranged roll positioned adjacent to the rotating pallet load.
- Rotational speeds of from about 5 to about 50 revolutions per minute are common.
- the turntable is completely stopped and the film is cut and attached to an underlying layer of film employing tack sealing, adhesive tape, spray adhesives, etc.
- the load being overwrapped can be shrouded in the film while the vertically arranged film roll remains in a fixed position.
- the film roll for example, in the case of relatively narrow film widths and relatively wide pallet loads, can be made to move in a vertical direction as the load is being overwrapped whereby a spiral wrapping effect is achieved on the packaged goods.
- Some of the properties desired of a good stretch wrap film are as follows: good cling or cohesion properties, high puncture resistance, good machine direction tear resistance, good transparency, low haze, low stress relaxation with time, high resistance to transverse tear especially when under machine direction tension, producible in thin gauges, low specific gravity and thus high yield in area per pound, good tensile toughness, high machine direction ultimate tensile strength, high machine direction ultimate elongation, and low modulus of elasticity.
- good tensile toughness high machine direction ultimate tensile strength, high machine direction ultimate elongation, and low modulus of elasticity.
- certain stretch wrap films have superior properties for load retention, but these films are characterized by having poor stretching characteristics.
- certain stretch wrap films having superior stretching properties have low load retention properties, thus limiting their use.
- the present invention is a multilayered film which has excellent stretch properties at a moderate load retention, excellent puncture resistance, total energy dart drop, high cling force and overall strength.
- the inventive film comprises outer cling layers, at least one inner polymeric layer and at least one core layer.
- the stretch wrap films of the present invention are designed for use in cling/cling film applications.
- the outer cling layers may be constructed of olefin polymer resins.
- the outer cling layers are preferably constructed with a copolymer or a terpolymer of ethylene and a minor amount of at least one alpha olefin of from about 3 to about 12 carbon atoms.
- the outer cling layers have a cling force to each other of at least about 140 g/inch.
- the inner polymeric layer located at a position between the first and second cling layers, comprises a polymer having a low polydispersity.
- the low polydispersity polymer has a polydispersity of from about 1 to about 4, a melt index (I 2 ) of from about 0.5 to about 10 g/10 min., and a melt flow ratio (I 20 /I 2 ) of from about 12 to about 22.
- the inner polymeric layer(s) are preferably produced utilizing metallocene catalyst polymerization techniques.
- the inner polymeric layer may comprise a blend of resins with the low polydispersity polymer.
- the core layer is also located at a position between the outer cling layers.
- the core layer may be comprised of a copolymer of propylene and ethylene having an ethylene content of from about 2 wt.% to about 6 wt.% and a melt flow ratio (I 20 /I 2 ) of from about 2 to about 15.
- the core layer is comprised of a heterophasic copolymer of propylene and ethylene having a melt flow ratio (I 20 /I 2 ) of from about 10 to about 18 and an ethylene content of from about 12 to about 30 wt.%.
- the core layer is comprised of a polypropylene copolymer having a melt flow ratio of from about 2 to about 15.
- the core layer may be comprised of blends of the above-described resins.
- the film is constructed with at least four layers; additional layers are contemplated.
- additional inner polymeric layers may be incorporated into the film between the outer cling layers, where such layers are constructed with the same or different metallocene-catalyzed polyethylene resins as the first inner polymeric layer.
- the multilayer film of the present invention will have a maximum stretch of at least 340%, and a machine direction stress level at 200% elongation of from about 1400 to about 1900 psi.
- FIG. 1 shows a four layer film constructed according to one embodiment of the present invention
- FIG. 2 shows a five layer film constructed according to one embodiment of the present invention.
- FIG. 3 shows a five layer film constructed according to another embodiment of the present invention.
- the multilayer stretch wrap films of the present invention are constructed with a first and a second outer cling layer, at least one inner polymeric layer and at least one core layer located at between the outer cling layers.
- the multilayer stretch wrap films of the present invention can be prepared as cast films by conventional coextrusion techniques.
- the stretch wrap films of the present invention are used in cling/cling applications.
- the outer cling layers of the stretch wrap films of the present invention may be constructed of olefin polymer resins.
- Suitable polyethylene resins are those ethylenic copolymers that comprise a major proportion by weight of ethylene copolymerized with a minor proportion by weight of an alpha olefin monomer containing about 3 to about 12, preferably about 4 to about 10, and more preferably about 4 to about 8, carbon atoms. These resins have a polydispersity which is preferably in the range of from about 3 to about 7.
- Ethylenic copolymers are those commonly referred to as linear low density polyethylenes (LLDPE) and very low density polyethylenes (VLDPE).
- LLDPE linear low density polyethylene
- VLDPE very low density polyethylene
- the ethylenic copolymers employed are those having from about 1 to about 20, preferably from about 1 to about 10 weight percent of said higher alpha olefin monomer copolymerized therein.
- the alpha olefin monomer employed in the ethylenic copolymer is selected from the group consisting of 1-butene, 3-methyl-l- butene, 3-methyl-l-pentene, 1-hexene, 4-methyl-l-pentene, 3-methyl- 1-hexene, 1- octene and 1-decene.
- the 1-hexene alpha olefins are particularly preferred.
- the LLDPE resins are prepared at relatively low pressures employing coordination-type catalysts. Reference may be made to U.S. Pat. Nos. 3,645,992, 4,076,698, 4,011,382,
- polyethylene resins that are desired to be used as the outer cling layers in the films of the present invention are those that are functionally defined as providing a cling force of at least about 140, preferably at least about 180, more preferably at least about 220, and in some cases at least about 260 grams/inch, as determined by the
- the cling force of the outer cling layers will be in the range of from about 140 to about 280 grams/inch.
- Common LLDPE resins that may be used to form such an outer cling layer include those having a relatively high weight percentage of n-hexane extractibles, as measured by the n-hexane extractibles method of 21 CF.R. 177.1520.
- the LLDPE used in the outer cling layers herein will contain from about 2 to about 10, preferably from about 2 to about 8, more preferably from about 2.5 to about 5, weight percent of n-hexane extractibles.
- the LLDPE resins that can be used in the outer cling layers herein have a density ranging from about 0.890 to about 0.940 g/cm 3 , more commonly from about 0.90 to about 0.93 g/cm 3 , and a melt index (I 2 ) of from about 1 to about 10 g/10 min., as determined by ASTM D1238. Particularly preferred are those LLDPE resins possessing densities within the range from about 0.917 to about 0.920 gm/cm 3 and a melt index of from about 2.0 to about 5.0 g/10 min., as determined by ASTM D1238. Examples of such LLDPE resins include those set forth in U.S. Pat. No.
- VLDPE resins that may be used in the outer cling layers herein have a density ranging from about 0.880 to about 0.912 g/cm 3 , more commonly from about 0.89 to about 0.91 g/cm " , and a melt index of from about 0.5 to about 5 g/10 min., preferably from about 1 to about 3 g/10 min.
- the LLDPE and VLDPE resins that can be used in the outer cling layers can be blended with minor amounts, e.g., up to about 40 weight percent total, of one or more other suitable resins to achieve a desired range of physical/mechanical properties in the film product.
- suitable resins e.g., ethyl vinyl acetate (EVA) copolymer, high pressure low density polyethylene (HPLDPE), and other LLDPE resins may be used for blending to obtain useful mixtures for forming the outer cling layers of the films of the present invention.
- the LLDPE and VLDPE resins that can be used in the outer cling layers herein may also contain known and conventional cling additives to augment the cling property that, at least in the case of the particularity preferred resins, is inherently exhibited.
- useful cling additives include poly-isobutylenes having a number average molecular weight in the range from about 1,000 to about 3,000, preferably about 1,200 to about 1,800, as measured by vapor phase osmometry, amorphous atactic polypropylenes, e.g., those having an average molecular weight of about 2000, and polyterpenes and ethylene- vinyl acetate copolymers containing from about 5 to about 15 weight percent copolymerized vinyl acetate.
- the optional cling additive can be present in the outer cling layers in a concentration of from about 0.5 to about 10 weight percent of the resin.
- other conventional film additives such as antioxidants, UV stabilizers, pigments, dyes, etc., may be present in the usual amounts.
- first and second layers may comprise, for example, a first ethylene monomer and a second monomer that comprises an acrylate.
- a first ethylene monomer and a second monomer that comprises an acrylate On example is an ethylene-acrylate (EA) polymer film shown in U.S. Pat. No. 5,049,423, which is incorporated herein by reference in its entirety.
- EA polymers generally have an acrylate content between about 2 to about 40%, preferably between about 10 to about 35%, by weight of the EA polymer.
- the acrylate useful in these polymers are those generally known in the art, preferably methyl, ethyl, and n-butyl acrylate.
- Other known cling layers are contemplated for the present invention.
- Either or both of the outer cling layers of the film can be treated by such known and conventional post-forming operations as corona discharge, chemical treatment, flame treatment, etc., to modify the printability or ink receptivity of the surface(s) or to impart other desirable characteristics thereto.
- the multilayer stretch wrap films of the present invention are constructed with at least one inner polymeric layer comprising a polymer resin having a low polydispersity and located between the outer cling layers.
- the inner polymeric layer comprises a polymer having a low polydispersity.
- the low polydispersity polymer may be prepared from a partially crystalline polyethylene resin that is a polymer prepared with ethylene and at least one alpha olefin monomer, e.g., a copolymer or terpolymer.
- the alpha olefin monomer generally has from about 3 to about 12 carbon atoms, preferably from about 4 to about 10 carbon atoms, and more preferably from about 6 to about 8 carbon atoms.
- the alpha olefin comonomer content is generally below about 30 weight percent, preferably below about 20 weight percent, and more preferably from about 1 to about 15 weight percent.
- Exemplary comonomers include propylene, 1-butene, 1- pentene, 1-hexene, 3-methyl-l-pentene, 4-methyl-l-pentene, 1 -octene, 1-decene, and 1- dodecene.
- the low polydispersity polymer generally has the characteristics associated with an LLDPE material, however it has improved properties as explained more fully below.
- the low polydispersity polymer defined herein will have a density of from about 0.88 to about 0.94 g/cm 3 , preferably from about 0.88 to about 0.93 g/cm 3 , and more preferably from about 0.88 to about 0.925 g/cm 3 .
- the average molecular weight of the copolymer can generally range from about 20,000 to about 500,000, preferably from about 50,000 to about 200,000.
- the molecular weight is determined by commonly used techniques such as size exclusion chromatography or gel permeation chromatography.
- the low polydispersity polymer should have a molecular weight distribution, or polydispersity, (M w /M n , "MWD") within the range of about 1 to about 4, preferably about 1.5 to about 4, more preferably about 2 to about 4, and even more preferably from about 2 to about 3.
- the ratio of the third moment to the second moment, M z /M w is generally below about 2.3, preferably below about 2.0, and more typically in the range of from about 1.6 to about 1.95.
- the melt flow ratio (MFR) of these resins is generally from about 12 to about 22, preferably from about 14 to about 20, and more preferably from about 16 to about 18.
- the melt index (MI), defined as the I 2 value should be in the range of from about 0.5 to about 10 g/10 min., preferably from about 1 to about 5 g/10 min. If additional resin materials are to be incorporated with the low polydispersity polymer, it is preferred to maintain the level of the low polydispersity polymer to at least about 60 weight percent of the inner polymeric layer.
- Useful low polydispersity polymers are available from, among others, Dow Chemical Company and Exxon Chemical Company who are producers of single site or constrained geometry catalyzed polyethylenes. These resins are commercially available as the AFFINITY and EXXACT polyethylenes (see Plastics World, p.33-36, Jan. 1995), and also as the ENHANCED POLYETHYLENE and EXCEED line of resins.
- the manufacture of such polyethylenes, generally by way of employing a metallocene catalyst system, is set forth in, among others, U.S. Pat. Nos.
- the above patents and publications generally report that these catalysts contain one or more cyclopentadienyl moieties in combination with a transition metal.
- the reactions can take place in either gas phase, high pressure, slurry, or solution polymerization schemes.
- At least one of the inner polymeric layers of the present invention is preferably constructed entirely with a low polydispersity polyethylene polymer, preferably produced by metallocene catalyst technology.
- the inner polymeric layer may also comprise a blend of the low polydispersity polymer with a second resin material.
- the second material may be an olefin polymer resin.
- this may include, but is not limited to, LLDPE, LDPE, HPLDPE, VLDPE, propylene resins or combinations thereof.
- the second resin material is preferably a LLDPE resin having a density of from about 0.89 to about 0.94 g/cm 3 , a LDPE resin having a density of from about 0.9 to about 0.935 g/cm 3 , a VLDPE resin having a density of from about 0.88 to about 0.91 g/cm 3 .
- the comonomer for the second resin material preferably has from about 4 to about 10, more preferably about 6 to about 8 carbon atoms. If the second resin material is to be incorporated with the metallocene-catalyzed resin, it is preferred to maintain the level of the metallocene-catalyzed resin to at least about 60 wt.% of the inner polymeric layer.
- the resultant blended polymer resin maintains the desired properties of the metallocene-catalyzed resin material and may be more economical for certain applications.
- the multilayer stretch wrap films of the present invention contains at least one core layer which is also located between the outer cling layers.
- the resin utilized in the core layer contributes to the ability of the multilayer films of the present invention to strain harden during the use of the film.
- the strain hardening characteristic can be generally described as the higher force necessary to further stretch the film beyond its already stretched state. This characteristic is best illustrated in the machine directional (MD) stress @ 200%, 250%, 300% and 350% elongation tests.
- Resins useful for preparing the core layer include random copolymers of propylene and ethylene with an ethylene content in the range of from about 2 to about 6 wt.%, preferably from about 2.5 to about 5.0 wt.% and most preferably from about 3.0 to about 4.5 wt.% of the core layer.
- the random ethylene-propylene copolymers have a melt flow ratio, defined as I 2 0/I2 and as determined in accordance to ASTM D- 1238, of from about 2 to about 15, preferably from about 3 to about 11, and more preferably from about 4 to about 7.
- the core layer may be prepared with heterophasic copolymers of propylene and ethylene.
- heterophasic copolymers comprise a propylene material with domains of ethylene interspersed.
- Useful heterophasic copolymers of propylene and ethylene are available from, among others, Himont, Inc.
- the heterophasic copolymers of propylene and ethylene have a melt flow ratio, defined as I 20 /I 2 and as determined in accordance to ASTM D-1238, of from about 10 to about 18, preferably from about 11 to about 16 and more preferably from about 12 to about 15.
- the ethylene content is in a range from about 12 to about 30 wt.%, preferably about 15 to about 26 wt.% and more preferably about 17 to about 24 wt.% of the core layer.
- the core layer may be prepared with polypropylene homopolymers.
- the polypropylene homopolymers have a melt flow ratio, defined as I 20 /I 2 and as determined in accordance to ASTM D-1238, of from about 2 to about 15, preferably from about 3 to about 11, and more preferably from about 4 to about 7.
- the core layer can comprise blends of the above-described resins.
- a heterophasic copolymer may be blended with various types of random copolymers of propylene and ethylene in varying amounts.
- the core layers comprised of either heterophasic copolymers, random copolymers of propylene and ethylene, or polypropylene homopolymers may be blended with olefin polymeric resins. These resins may include, but are not limited to, LLDPE, LDPE, HPLDPE, VLDPE, propylene resins or combinations thereof. It is preferable to maintain the level of the heterophasic copolymers, the random copolymers of propylene and ethylene, and the polypropylene homopolymers to at least about 50 wt.% of the core layer.
- the stretch wrap films of the present invention can be constructed to contain a plurality of layers in various combinations.
- the stretch wrap film will be of an A ⁇ B ⁇ C ⁇ A construction as depicted in FIG. 1 wherein the film layers (10) are the outer cling layers (layers A), film layer (20) is the inner polymeric layer (layer B), and film layer (30) is the core layer (layer C).
- the stretch wrap film may be of an A ⁇ B ⁇ C ⁇ B ⁇ A or A ⁇ C ⁇ B ⁇ C ⁇ A construction such as those depicted in FIGs. 2 and 3 where the film layers (10), (20), (30), are the outer cling, inner polymeric, and core layers, respectively, as previously described with respect to FIG. 1.
- stretch wrap films may be of an A ⁇ B ⁇ B ⁇ C ⁇ A or an A ⁇ B ⁇ C ⁇ C ⁇ A construction.
- Other types of multi-layered constructions are contemplated.
- the overall properties of the stretch wrap film of the present invention are such that it has a cling force to itself of at least about 140, generally at least about 180, preferably at least about 200, more preferably at least about 220, and in some cases at least 260 grams/inch as determined by ASTM D5458-94.
- the cling force of the film will be in the range of from about 140 to about 280 grams/inch.
- the stretch wrap film of this invention can, if desired, be provided in the non- stretched, i.e., unoriented, or at most only modestly stretched state prior to use.
- the films of the present invention are capable of being stretched from at least about 340, preferably at least about 375 and most preferably at least about 400 linear percent.
- the overall stretch wrap films have relatively high puncture resistance, as measured by the F-50 dart drop test procedure (ASTM D1709). It is the experience of those skilled in the art that the F-50 dart drop test is well correlated to the end use puncture resistance of stretch wrap films.
- the F-50 dart drop value of the films is at least about 150 grams, preferably at least about 200 grams, and more preferably from at least about 300 grams.
- the stretch wrap films of the present invention are preferably constructed so that the transverse direction tear resistance (TD tear), as determined by ASTM D1922, is at least about 500 g/mil, preferably at least about 600 g/mil, more preferably at least about 700 g/mil.
- the machine direction tear resistance (MD tear) as determined by ASTM D1922, of the film is generally at least about 175 g/mil, preferably at least about 225 g/mil, and more preferably at least about 275 g/mil.
- a parameter used to analyze the performance of stretch wrap films is the stress that results when the film is stretched a desired percentage of its original length. This stress is indicative of the load retention characteristics of the film and is determined in accordance with ASTM D882.
- the films of the present invention generally have a stress level at 200% elongation of from about 1400 psi to about 1900 psi, and more preferably from about 1600 to about 1800 psi.
- the films of the present invention generally have a stress level at 250% elongation of from about 1600 psi to about 2000 psi, and more preferably from about 1700 to about 1900 psi.
- the stretch wrap films of the present invention are preferably constructed so that the stretch force is from about 1.5 to about 2.2 lbs./inch.
- the film configurations are constructed according to conventional practices.
- the preferred processing technique is to coextrude and cast the films in a simultaneous fashion, however in some cases it may be appropriate to first coextrude at least two film layers and thereafter extrusion coat the remaining film layers.
- the resin materials are heated to their molten state and their viscosities are coordinated to prepare multilayer films in a uniform manner.
- the molten materials are conveyed to a coextrusion adapter that combines the molten materials to form a multilayer coextruded structure.
- the layered polymeric material is transferred through an extrusion die opened to a predetermined gap commonly in the range of between from 0.05 in. (0.13 cm) to about 0.012 in. (0.03 cm).
- the material is then drawn down to the intended gauge thickness by means of a primary chill or casting roll maintained at about 60 to about 130°F (15-55°C). Typical draw down ratios range from about 5: 1 to about 40: 1.
- the overall thickness of the stretch wrap film can vary widely according to end use specifications, but is generally in the range of the typical thicknesses for stretch wrap films. Conventional for such films is a thickness of from about 0.4 to about 3 mils, and is application specific.
- the outer cling layers may comprise from about 10 to about 50, preferably from about 10 to about 40, and more preferably from about 15 to about 30, weight percent of the stretch wrap film.
- the inner polymeric layer(s) may comprise from about 40 to about 85, preferably from about 40 to about 80, and more preferably from about 60 to about 75, weight percent of the stretch wrap film.
- the core layer(s) will account for the balance of the film, and generally will comprise from about 2 to about 50, preferably from about 5 to about 25, and more preferably from about 5 to about 15, weight percent of the stretch wrap film.
- the benefits provided from the core layer(s) are substantially obtained with up to about 7 weight percent, preferably up to about 12 weight percent, of the stretch wrap film.
- the incorporation of the core layer at these levels, in conjunction with the incorporation of the inner polymeric layer, has led to an unexpected moderation of holding force while still maintaining excellent stretch. These properties have been found to be appreciably enhanced surprisingly without a significant loss of other important film properties, and as a result the overall film stretch wrap performance has been enhanced.
- the probe energy test was conducted by use of an Instron Universal tester that records a continuous reading of the force (stress) and penetration (strain) curve.
- a 6 in. by 6 in. film specimen is securely mounted to a compression load cell to expose a 4 in. by 4 in. area.
- a hemispherically shaped (1 in. dia.) stainless steel probe, traveling at a constant speed of 10 inVmin. is lowered into the film.
- a stress/strain curve is recorded and plotted. Peak force is the maximum force encountered.
- the machine is used to integrate the area under the curve, which is indicative of the energy consumed during the penetration to rupture testing of the film.
- the films were prepared using a commercially available cast film line machine.
- the material melt temperatures ranged from about 380 to about 580°F and were chosen to match melt viscosities of the various resins.
- the melts were conveyed to a coextrusion adapter that combines the melt flows into a multilayer coextruded structure. This layered flow was distributed through a single manifold film extrusion die to the required width.
- the die gap opening was nominally 0.025 inches.
- the material was drawn down to the final gauge.
- the material draw down ratio was about 31:1 for the 0.8 mil films.
- a vacuum box was used to pin the melt exiting the die opening to a primary chill roll maintained at about 90°F.
- the films were tested for performance in a stretch wrapper constructed with equipment to determine various film properties during the stretching operation. The testing was conducted at rates similar to those employed by commercial equipment. The film width was 20 inches for this test machine. The machine direction (MD) force at 200% stretch and maximum stretch % were determined.
- MD machine direction
- Tables 2 and 3 The results of the tests appear in Tables 2 and 3.
- the comparative films were films 1-4 and the inventive films were films 5-12.
- the comparative films 1 and 2 were compared with inventive films 5-10, while comparative films 3 and 4 were compared with inventive films 11 and 12.
- the comparative films were 1-2 and the inventive films were films 13-14.
- the outer film layers A (cling layers) of the inventive films 5-14 were comprised of a linear low density polyethylene (LLDPE) resin.
- LLDPE resin in layers A had a density of 0.917 g/cm 3 and a melt index (I 2 ) of 3.3 g/10 min.
- the inner polymeric layers B of each inventive film were comprised of 100% metallocene-catalyzed linear low density polyethylene or "mLLDPE". Film layers B were formed from an alpha olefin comonomer of 1- hexene.
- the core layer C of inventive films 5-12 was comprised of a random copolymer of propylene and ethylene having a varying amount of ethylene and varying melt flow ratios (see "P/E Copolymer" in Table 2). In the inventive films 5-12 of Table 2, the ethylene content ranged from 3.0 to 4.5 wt.% of the core layer, while the melt flow ratios ranged from 4.5 to 6.5.
- the core layer C of inventive films 13-14 was comprised of a heterophasic copolymer of propylene with domains of ethylene interspersed.
- the heterophasic copolymer had an ethylene content of 18 wt.% of the core layer and a melt flow ratio of 12.0 (see "Heterophasic P/E" in
- the comparative films (films 1-4) in Tables 2 and 3 were comprised of the same outer layer resin A and the same inner layer resin B as described above in the inventive films.
- the core layer C of the comparative films 1-4 was comprised of a low density polyethylene resin (LDPE) having a melt index of 2.0 g/10 min. and a density of 0.918 g/cm 3 .
- LDPE low density polyethylene resin
- All of the comparative films 1-4 and the inventive films 5-14 comprised about 20 wt.% of layers A (outer film layers), about 70 wt.% of layers B (inner layers) and about 10 wt.% of layer C (core layer).
- each outer film layer of A was about 10 wt.% and each inner polymeric layer B was about 35 wt.%.
- the inventive films 5-10 generally had approximately equivalent maximum stretch values than the average of the maximum stretch for comparative films 1 and 2 (see maximum stretch %).
- the inventive films 5-10 generally had lower stress values when the film is stretched a desired percentage of its original length when compared to comparative films 1 and 2 (see MD Stress @ 200%, 250%, 300% and 350%).
- Inventive films 5-10 had higher F-50 dart drop values and total energy dart drop values than the average of the comparative films 1 and 2.
- Inventive films 11 and 12 had a lower maximum stretch value than comparative films 3 and 4 (see maximum stretch %). Inventive films 11 and 12 also had a higher F-50 dart drop and a total energy dart drop than comparative films 3 and 4. The inventive films 11 and 12 showed a moderate holding force compared to the comparative films 3 and 4 (see MD Stress @ 200%, 250%, 300% and 350%).
- inventive films 13 and 14 (core layers comprised of a heterophasic copolymer of propylene and ethylene) had higher maximum stretch values than the average of the values for comparative films 1 and 2 (see maximum stretch %).
- the inventive films 13 and 14 had lower stress values when the film is stretched a desired percentage of its original length as compared to comparative films
- Inventive films 13 and 14 had similar F-50 dart drop values, but had higher total energy dart drop values than the comparative films 1 and 2.
Abstract
Description
Claims
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AU80682/98A AU8068298A (en) | 1997-07-02 | 1998-06-11 | Multilayered metallocene stretch wrap films |
CA 2307183 CA2307183C (en) | 1997-07-02 | 1998-06-11 | Multilayered metallocene stretch wrap films |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US08/886,953 | 1997-07-02 | ||
US08/886,953 US5902684A (en) | 1996-03-12 | 1997-07-02 | Multilayered Metallocene stretch wrap films |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1999001279A1 true WO1999001279A1 (en) | 1999-01-14 |
Family
ID=25390138
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/US1998/012221 WO1999001279A1 (en) | 1997-07-02 | 1998-06-11 | Multilayered metallocene stretch wrap films |
Country Status (4)
Country | Link |
---|---|
US (1) | US5902684A (en) |
AU (1) | AU8068298A (en) |
CA (1) | CA2307183C (en) |
WO (1) | WO1999001279A1 (en) |
Families Citing this family (40)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5998017A (en) * | 1996-03-12 | 1999-12-07 | Tenneco Packaging | Stretch wrap films |
USRE38429E1 (en) * | 1996-03-12 | 2004-02-17 | Tyco Plastics Services Ag | Stretch wrap films |
US6093480A (en) * | 1997-05-21 | 2000-07-25 | Tenneco Packaging | Stretch wrap films |
US6083611A (en) * | 1997-11-12 | 2000-07-04 | Tenneco Packaging, Inc. | Roll wrap film |
US6420022B2 (en) * | 1998-02-02 | 2002-07-16 | Reynolds Consumer Products, Inc. | Differential cling forage wrapping film; wrapped bale; method for producing differential cling film; and method for wrapping forage |
US6361875B1 (en) | 1999-11-20 | 2002-03-26 | Intertape, Inc. | Premium hand wrap multi-layer film products |
US6495245B1 (en) * | 1999-11-20 | 2002-12-17 | Intertape, Inc. | Hand wrap multilayer film products |
US6299968B1 (en) | 1999-11-20 | 2001-10-09 | Intertape Inc. | General purpose multilayer film products |
US6492010B1 (en) * | 1999-11-20 | 2002-12-10 | Intertape, Inc. | Premium stretch multilayer film products |
SG147271A1 (en) * | 2000-01-26 | 2008-11-28 | Mitsui Chemical Inc 22 51 56 D | Olefin polymer and process for preparing the same |
US6433088B1 (en) | 2000-08-04 | 2002-08-13 | Equistar Chemicals, Lp | Clear and printable polypropylene films |
US6440533B1 (en) * | 2000-09-22 | 2002-08-27 | Tredegar Film Products Corporation | PVC replacement film |
US6924243B2 (en) * | 2001-05-29 | 2005-08-02 | Owens Corning Fiberglas Technology, Inc. | High performance fire-retardant kraft facing for fiberglass insulation |
CA2473701A1 (en) * | 2002-01-16 | 2003-07-31 | Trevor Arthurs | Multi-layered flame retardant wrap |
US6913147B2 (en) | 2002-05-16 | 2005-07-05 | Sealed Air Corporation (Us) | Packaging structure having a frame and film |
US6864195B2 (en) * | 2002-08-15 | 2005-03-08 | Bfs Diversified Products, Llc | Heat weldable roofing membrane |
US7422786B2 (en) * | 2003-09-24 | 2008-09-09 | Exxonmobil Chemical Patents Inc. | Collation shrink |
US20050096613A1 (en) * | 2003-11-04 | 2005-05-05 | Carper James D. | Cling film fastening system for disposable soft goods |
MXPA06006929A (en) * | 2003-12-18 | 2006-09-04 | Dow Global Technologies Inc | Film with superior impact resistance and improved catastrophic failure resistance under high strain rate. |
US7175918B2 (en) * | 2004-04-27 | 2007-02-13 | Equistar Chemicals, Lp | Polyolefin compositions |
US7183005B2 (en) * | 2004-08-20 | 2007-02-27 | Exxonmobil Chemical Patents Inc. | Impact strength improvement of regrind |
US20060147663A1 (en) * | 2004-12-30 | 2006-07-06 | Fina Technology, Inc. | Co-extruded film structures of polypropylene impact copolymer with other polymers |
US7951873B2 (en) * | 2006-05-05 | 2011-05-31 | Exxonmobil Chemical Patents Inc. | Linear low density polymer blends and articles made therefrom |
US8247065B2 (en) * | 2006-05-31 | 2012-08-21 | Exxonmobil Chemical Patents Inc. | Linear polymers, polymer blends, and articles made therefrom |
US20090156764A1 (en) * | 2007-12-18 | 2009-06-18 | Malakoff Alan M | Ethylene-Based Polymers and Articles Made Therefrom |
US20090269566A1 (en) * | 2008-04-23 | 2009-10-29 | Berry Plastics Corporation | Pre-stretched multi-layer stretch film |
BR112012025925B1 (en) | 2010-04-13 | 2020-03-17 | Univation Technologies, Llc | POLYMERIC MIXTURE AND FILM |
WO2012024472A1 (en) | 2010-08-18 | 2012-02-23 | Sun Chemical Corporation | Chlorine-free ink and coating compositions & a method for printing on untreated polyolefin films with improved adhesion |
PL223808B1 (en) * | 2012-02-16 | 2016-11-30 | Zakład Produkcji Folii Efekt Plus Spółka Z Ograniczoną | Method for preparing a five-stretch polyolefin film |
WO2013133956A2 (en) | 2012-03-05 | 2013-09-12 | Univation Technologies, Llc | Methods for making catalyst compositions and polymer products produced therefrom |
US9272795B2 (en) | 2012-05-17 | 2016-03-01 | Henkel IP & Holding GmbH | Integral hot melt adhesive packaging films and use thereof |
US9346247B2 (en) | 2013-05-01 | 2016-05-24 | Paragon Films, Inc. | Stretch films containing random copolymer polypropylene resins in adjacent layers of a nanolayer structure |
EP3126142B1 (en) * | 2014-04-01 | 2020-01-01 | Saudi Basic Industries Corporation | Multilayer film |
MX2018005152A (en) | 2015-10-27 | 2018-06-06 | Berry Plastics Corp | Multi-layer film. |
WO2018009783A1 (en) | 2016-07-07 | 2018-01-11 | Berry Global, Inc. | Multi-layer film |
US11059614B2 (en) * | 2016-08-29 | 2021-07-13 | Johns Manville | Insulation packaging system |
EP3519466B1 (en) | 2016-09-27 | 2023-07-05 | Univation Technologies, LLC | Method for long chain branching control in polyethylene production |
ES2927634T3 (en) * | 2017-12-20 | 2022-11-08 | Dow Global Technologies Llc | Multilayer cast films and manufacturing methods thereof |
AR118648A1 (en) * | 2019-04-24 | 2021-10-20 | Dow Global Technologies Llc | IMPROVED TEAR RESISTANCE MULTI-LAYER STRETCH FILM |
WO2021011576A1 (en) * | 2019-07-17 | 2021-01-21 | Jindal Films Americas Llc | Heat-stable biaxially oriented polypropylene films |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5431284A (en) * | 1988-10-25 | 1995-07-11 | Mobil Oil Corporation | Multi-layer coextruded polyolefin stretch wrapped plurality of goods |
EP0705687A1 (en) * | 1994-10-06 | 1996-04-10 | Sumitomo Chemical Company, Limited | Multilayer packaging film |
WO1996029203A2 (en) * | 1995-03-18 | 1996-09-26 | Mobil Plastics Europe Inc. | Stretch wrap plastic film |
Family Cites Families (76)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4076698A (en) * | 1956-03-01 | 1978-02-28 | E. I. Du Pont De Nemours And Company | Hydrocarbon interpolymer compositions |
CA849081A (en) * | 1967-03-02 | 1970-08-11 | Du Pont Of Canada Limited | PRODUCTION OF ETHYLENE/.alpha.-OLEFIN COPOLYMERS OF IMPROVED PHYSICAL PROPERTIES |
US3748962A (en) * | 1971-12-16 | 1973-07-31 | Barber Colman Co | Hob shifter |
US4050221A (en) * | 1973-04-04 | 1977-09-27 | Lantech, Inc. | Stretch-wrapped package, process and apparatus |
US3986611A (en) * | 1973-07-06 | 1976-10-19 | Union Carbide Corporation | Cling film overwrap for palletized articles |
GB1492379A (en) * | 1974-04-22 | 1977-11-16 | Dow Chemical Co | Polymerization catalyst |
US4011382A (en) * | 1975-03-10 | 1977-03-08 | Union Carbide Corporation | Preparation of low and medium density ethylene polymer in fluid bed reactor |
JPS5952643B2 (en) * | 1977-01-27 | 1984-12-20 | 三井化学株式会社 | ethylene copolymer |
US4302566A (en) * | 1978-03-31 | 1981-11-24 | Union Carbide Corporation | Preparation of ethylene copolymers in fluid bed reactor |
US4302565A (en) * | 1978-03-31 | 1981-11-24 | Union Carbide Corporation | Impregnated polymerization catalyst, process for preparing, and use for ethylene copolymerization |
US4399180A (en) * | 1978-09-15 | 1983-08-16 | Mobil Oil Corporation | Coextruded thermoplastic stretch-wrap |
US4359561A (en) * | 1979-06-18 | 1982-11-16 | Union Carbide Corporation | High tear strength polymers |
US4399173A (en) * | 1982-01-04 | 1983-08-16 | Union Carbide Corporation | Multilayer films comprising low pressure, low density polyethylene |
US4418114A (en) * | 1982-04-29 | 1983-11-29 | Mobil Oil Corporation | Coextruded thermoplastic stretch-wrap |
US4461873A (en) * | 1982-06-22 | 1984-07-24 | Phillips Petroleum Company | Ethylene polymer blends |
US4522987A (en) * | 1982-07-09 | 1985-06-11 | Phillips Petroleum Company | Low density polyethylene |
US4588650A (en) * | 1982-09-29 | 1986-05-13 | The Dow Chemical Company | Olefin polymer stretch/cling film |
US4511609A (en) * | 1982-09-30 | 1985-04-16 | Union Carbide Corporation | Multilayer trash bag film |
US4565720A (en) * | 1983-07-27 | 1986-01-21 | Idemitsu Petrochemical Co., Ltd. | Packaging bag |
JPS60105541A (en) * | 1983-11-14 | 1985-06-11 | 出光石油化学株式会社 | Multilayer film |
US4808561A (en) * | 1985-06-21 | 1989-02-28 | Exxon Chemical Patents Inc. | Supported polymerization catalyst |
US5124418A (en) * | 1985-11-15 | 1992-06-23 | Exxon Chemical Patents Inc. | Supported polymerization catalyst |
US5077255A (en) * | 1986-09-09 | 1991-12-31 | Exxon Chemical Patents Inc. | New supported polymerization catalyst |
US5084534A (en) * | 1987-06-04 | 1992-01-28 | Exxon Chemical Patents, Inc. | High pressure, high temperature polymerization of ethylene |
US5273809A (en) * | 1987-04-17 | 1993-12-28 | Mobil Oil Corporation | Multilayer stretch wrap film inherently exhibiting a significant cling property |
US5617707A (en) * | 1987-04-17 | 1997-04-08 | Mobil Oil Corporation | Stretch wrap film inherently exhibiting a significant cling property |
US4833017A (en) * | 1987-04-17 | 1989-05-23 | Mobil Oil Corporation | Particle-impregnated one-sided cling stretch wrap film |
US4871523A (en) * | 1987-05-15 | 1989-10-03 | Exxon Chemical Patents Inc. | Vanadium tetrachloride stabilization |
JPH0777754B2 (en) * | 1987-07-07 | 1995-08-23 | 三井石油化学工業株式会社 | Stretch wrapping film |
JPH06104802B2 (en) * | 1987-10-19 | 1994-12-21 | 大日本インキ化学工業株式会社 | Resin composition for urethane paint |
US5049423A (en) * | 1987-11-19 | 1991-09-17 | Exxon Chemical Patents Inc. | Composite thermoplastic films for use in stretch/cling applications |
US5173343A (en) * | 1987-11-19 | 1992-12-22 | Exxon Chemical Patents Inc. | Narrow molecular weight distribution ethylene-acrylate cling layer in stretch/cling films |
US4937301A (en) * | 1987-12-17 | 1990-06-26 | Exxon Chemical Patents Inc. | Method for preparing a supported metallocene-alumoxane catalyst for gas phase polymerization |
US4925821A (en) * | 1987-12-17 | 1990-05-15 | Exxon Chemical Patents Inc. | Method for utilizing triethyaluminum to prepare an alumoxane support for an active metallocene catalyst |
JP2682628B2 (en) * | 1987-12-28 | 1997-11-26 | バブコツク日立株式会社 | Nitrogen oxide removal method and removal catalyst |
US4871705A (en) * | 1988-06-16 | 1989-10-03 | Exxon Chemical Patents Inc. | Process for production of a high molecular weight ethylene a-olefin elastomer with a metallocene alumoxane catalyst |
US5001205A (en) * | 1988-06-16 | 1991-03-19 | Exxon Chemical Patents Inc. | Process for production of a high molecular weight ethylene α-olefin elastomer with a metallocene alumoxane catalyst |
US5382631A (en) * | 1988-09-30 | 1995-01-17 | Exxon Chemical Patents Inc. | Linear ethylene interpolymer blends of interpolymers having narrow molecular weight and composition distributions |
US5019315A (en) * | 1988-10-25 | 1991-05-28 | Mobil Oil Corporation | Preparing multi-layer coextruded polyolefin stretch wrap films |
US5006500A (en) * | 1988-10-27 | 1991-04-09 | Exxon Chemical Patents Inc. | Olefin polymerization catalyst from trialkylaluminum mixture, silica gel and a metallocene |
US4904631A (en) * | 1988-11-08 | 1990-02-27 | Exxon Chemical Patents, Inc. | Supported vanadium catalyst for polymerization of olefins and a process of preparing and using the same |
US5026798A (en) * | 1989-09-13 | 1991-06-25 | Exxon Chemical Patents Inc. | Process for producing crystalline poly-α-olefins with a monocyclopentadienyl transition metal catalyst system |
US5085927A (en) * | 1990-04-10 | 1992-02-04 | Paragon Films, Inc. | Stretch film cling enhancement by addition of elastomers |
US5272236A (en) * | 1991-10-15 | 1993-12-21 | The Dow Chemical Company | Elastic substantially linear olefin polymers |
US5079205A (en) * | 1990-07-13 | 1992-01-07 | Exxon Chemical Patents Inc. | Group ivb, vb and vib metal hydrocarbyloxides, with alumoxane for olefin polymerization |
MX9200724A (en) * | 1991-02-22 | 1993-05-01 | Exxon Chemical Patents Inc | HEAT SEALABLE MIX OF POLYETHYLENE OR PLASTOMER OF VERY LOW DENSITY WITH POLYMERS BASED ON POLYPROPYLENE AND THERMAL SEALABLE FILM AS WELL AS ARTICLES MADE WITH THOSE. |
CA2107095A1 (en) * | 1991-03-29 | 1992-09-30 | Dennis N. Caulfield | Polymeric material and clear film produced therefrom |
US5395471A (en) * | 1991-10-15 | 1995-03-07 | The Dow Chemical Company | High drawdown extrusion process with greater resistance to draw resonance |
US5278272A (en) * | 1991-10-15 | 1994-01-11 | The Dow Chemical Company | Elastic substantialy linear olefin polymers |
US5206075A (en) * | 1991-12-19 | 1993-04-27 | Exxon Chemical Patents Inc. | Sealable polyolefin films containing very low density ethylene copolymers |
US5530065A (en) * | 1992-01-07 | 1996-06-25 | Exxon Chemical Patents Inc. | Heat sealable films and articles made therefrom |
US5451450A (en) * | 1992-02-19 | 1995-09-19 | Exxon Chemical Patents Inc. | Elastic articles and a process for their production |
US5272016A (en) * | 1992-03-23 | 1993-12-21 | Viskase Corporation | Multilayer stretch/shrink film |
US5283128A (en) * | 1992-03-23 | 1994-02-01 | Viskase Corporation | Biaxially oriented heat shrinkable film |
US5279872A (en) * | 1992-03-23 | 1994-01-18 | Viskase Corporation | Multilayer stretch/shrink film |
DE4230869A1 (en) * | 1992-09-16 | 1994-03-17 | Basf Ag | Packaging film consisting of a sealing layer and a carrier layer |
KR100262833B1 (en) * | 1992-09-16 | 2000-08-01 | 벤 씨. 카덴헤드 | Soft films having enhanced physical properties |
NZ248674A (en) * | 1992-09-18 | 1996-03-26 | Grace W R & Co | Heat-shrinkable multilayer film comprising a layer of propylene polymer or copolymer and hydrocarbon resin, and outer layers of various other polymers |
US5482771A (en) * | 1992-09-18 | 1996-01-09 | W. R. Grace & Co.-Conn. | Moisutre barrier film |
US5399426A (en) * | 1992-10-19 | 1995-03-21 | The Dow Chemical Company | Polyethylene stretch films |
US5482770A (en) * | 1992-11-03 | 1996-01-09 | W. R. Grace & Co.-Conn. | Highly oriented multilayer film |
US5604043A (en) * | 1993-09-20 | 1997-02-18 | W.R. Grace & Co.-Conn. | Heat shrinkable films containing single site catalyzed copolymers having long chain branching |
US5419934A (en) * | 1992-12-18 | 1995-05-30 | Mobil Oil Corporation | Multilayer coextruded polyolefin stretch wrap films |
AU673048B2 (en) * | 1992-12-28 | 1996-10-24 | Mobil Oil Corporation | Linear low density polyethylene film |
US5420220A (en) * | 1993-03-25 | 1995-05-30 | Mobil Oil Corporation | LLDPE films |
US5334428A (en) * | 1992-12-28 | 1994-08-02 | Mobil Oil Corporation | Multilayer coextruded linear low density polyethylene stretch wrap films |
US5374459A (en) * | 1993-04-06 | 1994-12-20 | W. R. Grace & Co.-Conn. | Packaging material for long-term storage of food products |
US5523136A (en) * | 1993-04-30 | 1996-06-04 | Cypress Packaging | Packaging film, packages and methods for using them |
CN1087326C (en) * | 1993-05-13 | 2002-07-10 | 埃克森美孚化学专利公司 | Ethylene copolymers having narrow composition distribution, their production and use |
US5397613A (en) * | 1993-07-12 | 1995-03-14 | Viskase Corporation | Puncture resistant heat shrinkable film containing narrow molecular weight ethylene alpha olefin |
US5419795A (en) * | 1993-07-29 | 1995-05-30 | W. R. Grace & Co.-Conn. | High slip packaging film with trapped print |
US5462807A (en) * | 1993-08-20 | 1995-10-31 | Exxon Chemical Patents Inc. | Heat sealable films and articles |
US5407732A (en) * | 1993-10-29 | 1995-04-18 | Mobil Oil Corporation | Multi-layer coextruded polyolefin stretch wrap films |
US5491019A (en) * | 1994-03-28 | 1996-02-13 | W. R. Grace & Co.-Conn. | Oxygen-permeable multilayer film |
US5460861A (en) * | 1994-05-10 | 1995-10-24 | Viskase Corporation | Multilayer stretch/shrink film |
US5558930A (en) * | 1994-06-23 | 1996-09-24 | Tredegar Industries, Inc. | Heat sealable, high moisture barrier film and method of making same |
-
1997
- 1997-07-02 US US08/886,953 patent/US5902684A/en not_active Expired - Lifetime
-
1998
- 1998-06-11 WO PCT/US1998/012221 patent/WO1999001279A1/en active Application Filing
- 1998-06-11 CA CA 2307183 patent/CA2307183C/en not_active Expired - Lifetime
- 1998-06-11 AU AU80682/98A patent/AU8068298A/en not_active Abandoned
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5431284A (en) * | 1988-10-25 | 1995-07-11 | Mobil Oil Corporation | Multi-layer coextruded polyolefin stretch wrapped plurality of goods |
EP0705687A1 (en) * | 1994-10-06 | 1996-04-10 | Sumitomo Chemical Company, Limited | Multilayer packaging film |
WO1996029203A2 (en) * | 1995-03-18 | 1996-09-26 | Mobil Plastics Europe Inc. | Stretch wrap plastic film |
Also Published As
Publication number | Publication date |
---|---|
CA2307183A1 (en) | 1999-01-14 |
CA2307183C (en) | 2007-01-23 |
US5902684A (en) | 1999-05-11 |
AU8068298A (en) | 1999-01-25 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US5902684A (en) | Multilayered Metallocene stretch wrap films | |
US6093480A (en) | Stretch wrap films | |
US5907942A (en) | Stretch wrap films | |
US5998017A (en) | Stretch wrap films | |
US5752362A (en) | Stretch wrap films | |
US5907943A (en) | Stretch wrap films | |
US5749202A (en) | Stretch wrap films | |
USRE38429E1 (en) | Stretch wrap films | |
US5922441A (en) | Stretch wrap films | |
US6083611A (en) | Roll wrap film | |
US5814399A (en) | Stretch wrap films | |
US5407732A (en) | Multi-layer coextruded polyolefin stretch wrap films | |
CA2150820C (en) | Multilayer coextruded polyolefin stretch wrap films | |
US5976682A (en) | Stretch wrap films | |
US6265055B1 (en) | Multilayer stretch cling film | |
US5431284A (en) | Multi-layer coextruded polyolefin stretch wrapped plurality of goods | |
US5019315A (en) | Preparing multi-layer coextruded polyolefin stretch wrap films | |
ES2264080T3 (en) | RETRACTABLE FILM OF UNION OF ELEMENTS. | |
US6013378A (en) | HMW HDPE film with improved impact strength | |
US5989725A (en) | Clear high molecular weight film | |
US5261536A (en) | Multi-layer coextruded polyolefin stretch wrap films | |
US6602598B1 (en) | Quiet unwind stretch wrap film | |
US6159587A (en) | Stretchable multilayer films | |
US6299968B1 (en) | General purpose multilayer film products | |
AU2003248954B2 (en) | Schrink film |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AK | Designated states |
Kind code of ref document: A1 Designated state(s): AL AM AT AU AZ BA BB BG BR BY CA CH CN CU CZ DE DK EE ES FI GB GE GH HU ID IL IS JP KE KG KP KR KZ LC LK LR LS LT LU LV MD MG MK MN MW MX NO NZ PL PT RO RU SD SE SG SI SK SL TJ TM TR TT UA UG UZ VN YU ZW |
|
AL | Designated countries for regional patents |
Kind code of ref document: A1 Designated state(s): GH GM KE LS MW SD SZ UG ZW AM AZ BY KG KZ MD RU TJ TM AT BE CH CY DE DK ES FI FR GB GR IE IT LU MC NL PT SE BF BJ CF CG CI CM GA GN ML MR NE SN TD TG |
|
DFPE | Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed before 20040101) | ||
121 | Ep: the epo has been informed by wipo that ep was designated in this application | ||
ENP | Entry into the national phase |
Ref document number: 2307183 Country of ref document: CA Ref country code: CA Ref document number: 2307183 Kind code of ref document: A Format of ref document f/p: F |
|
NENP | Non-entry into the national phase |
Ref country code: KR |
|
NENP | Non-entry into the national phase |
Ref country code: JP Ref document number: 1999507176 Format of ref document f/p: F |
|
REG | Reference to national code |
Ref country code: DE Ref legal event code: 8642 |
|
122 | Ep: pct application non-entry in european phase |