CA2453748A1 - Wrapping films with mating cling strips - Google Patents
Wrapping films with mating cling strips Download PDFInfo
- Publication number
- CA2453748A1 CA2453748A1 CA 2453748 CA2453748A CA2453748A1 CA 2453748 A1 CA2453748 A1 CA 2453748A1 CA 2453748 CA2453748 CA 2453748 CA 2453748 A CA2453748 A CA 2453748A CA 2453748 A1 CA2453748 A1 CA 2453748A1
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- Canada
- Prior art keywords
- cling
- film
- ply
- ethylene
- layer
- 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
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Classifications
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- 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
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- 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
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B27/00—Layered products comprising a layer of synthetic resin
- B32B27/30—Layered products comprising a layer of synthetic resin comprising vinyl (co)polymers; comprising acrylic (co)polymers
- B32B27/306—Layered products comprising a layer of synthetic resin comprising vinyl (co)polymers; comprising acrylic (co)polymers comprising vinyl acetate or vinyl alcohol (co)polymers
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- 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
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- 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
- B32B2272/00—Resin or rubber layer comprising scrap, waste or recycling material
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- 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
- B32B2323/043—HDPE, i.e. high density polyethylene
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- 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
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- 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
- B32B2331/00—Polyvinylesters
- B32B2331/04—Polymers of vinyl acetate, e.g. PVA
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- 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
- Y10T428/13—Hollow or container type article [e.g., tube, vase, etc.]
- Y10T428/1352—Polymer or resin containing [i.e., natural or synthetic]
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- 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
- Y10T428/13—Hollow or container type article [e.g., tube, vase, etc.]
- Y10T428/1352—Polymer or resin containing [i.e., natural or synthetic]
- Y10T428/1369—Fiber or fibers wound around each other or into a self-sustaining shape [e.g., yarn, braid, fibers shaped around a core, etc.]
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- 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
- Y10T428/13—Hollow or container type article [e.g., tube, vase, etc.]
- Y10T428/1352—Polymer or resin containing [i.e., natural or synthetic]
- Y10T428/139—Open-ended, self-supporting conduit, cylinder, or tube-type article
- Y10T428/1393—Multilayer [continuous layer]
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- 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
- Y10T428/19—Sheets or webs edge spliced or joined
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- 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
- Y10T428/24—Structurally defined web or sheet [e.g., overall dimension, etc.]
- Y10T428/24752—Laterally noncoextensive components
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- 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
- Y10T428/24—Structurally defined web or sheet [e.g., overall dimension, etc.]
- Y10T428/24942—Structurally defined web or sheet [e.g., overall dimension, etc.] including components having same physical characteristic in differing degree
- Y10T428/24992—Density or compression of components
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- 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
- Y10T428/249921—Web or sheet containing structurally defined element or component
- Y10T428/249922—Embodying intertwined or helical component[s]
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- 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
- Y10T428/28—Web or sheet containing structurally defined element or component and having an adhesive outermost layer
- Y10T428/2852—Adhesive compositions
- Y10T428/2878—Adhesive compositions including addition polymer from unsaturated monomer
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- 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
Abstract
A cling film system includes first and second film piles having different composition. Each film ply includes at least one cling layer and, desirably, one or more additional layers. Each film ply includes an overlapping portion and a second portion. The cling layer of the first film ply engages the cling layer of the second film ply in the overlapping portion of the first film ply and in the overlapping portion of the second film ply.
Description
PIPING h'IIJS '~ITi~A'~'IT1G ~IJYNST PS
I~I_,~~' 'T~' IhI'TI~i~
This in'Tention is directed to an improved cling falm system, useful for wrapping steel coils and other articles in a spiral fashion.
~A~~I~CI D ~F rE II~Vh,IV'TI~N
Various single layer and multiple layer cling films have been used for wrapping steel coils and other articles. Cling films are typically based on polyethylene homopolymers or copolymers including, without limitation, low density polyethylene, linear low density polyethylene, ethylene vinyl acetate and the like. In i0 addition to the polymer co~~ponents, these films typically include a balance of additives which are intended to improve c:~ing, and additives employed for other purposes which may have an undesirable anti-cling effect.
A cling filrr~ ~rrust have the obi ity to stick or cling to itself, or to other films having the same composition. Cane coA-zventional cling falm is based on linear low density polyethylene modified with a cling additive, such as polyisobutylene, a volatile corrosion inhibitor, such as sodiurr~ nitrite, as well as other chemicals described below that bloom to the surface and deposit on the steel surface to inhibit corrosion. The corrosion inhibiting chemicals tend to diminish or eliminate the cling of the linear low density polyethylene film. 'Tl~e polyisobutylene restores the cling to 2~ the f lm, so that the film will cling or stick to itself during wrapping of an article.
ITVV-13 X96 2 I/clb d Multiple layer films have also been developed, having very high cling properties in an outer facing layer of the film and corrosion inhibiting additives in an inner facing layer. The corrosion inhibiting additives care thus readily migrate to the article being wrapped. 'fhe very high cling properties of the outer facing layer tend to offset the low cling properties of the inner facing layer, so that the two surfaces adequately cling together daring wrapping.
~ther cling films include volatile corm>sic~n inhibitors applied as a coating in stripes or other spaced apart patterns. ~'he areas on the f~lnr~
away from the stripes are devoid of these additives, allowi~ag opposing film surfaces to cling together lfl during wrapping. These cling dlr.'s arE; relatively complex and expensive to manufacture.
Another difficulty encountered with prior cling ~lrr~s (both single layer and mufti-layer) is that they nay puncture and tear whe~~ exposed to the sharp edges of steel coils or other articles being wrapped. Thus, tlT~ere is a need or desire for a cling f lm system which a) provides improved cling properties while aiding corrosion resistance, b) is relatively inexpensive to anufactc~.re, arid c) has unproved toughness and puncture resistance.
SIJI''Sl C~T~I~NN'I'I~N
The present invention is directed to a cling film sy,stern including at least 2~ two plies. The first ply has a first surface and a second surface, the second ply has a first surface and a second surface, and the second surface of the first ply faces and IT~N-13896 3 Ilclb l partially overlaps the first surface of the second ply. 'The first ply and the second ply rnay have different compos;dons fAom each. other. T'he second surface ~f the first ply and the first surface of the second ply have cling properties.
~'he first ply and second ply may be formed separately, as separate films, and brought together before or during wrapping of the article so that the second surface of the first ply partially overlaps the first surface; of the second ply. 'T he first ply and the second ply may each have.a single layer, or multiple layers, and need not have the carne number of layers. ~'he first ply and the second ply may each be formed by cast or blown film extrusion or coextr~asion, and need not be formed by the same ~ 0 process.
In one embodiment, the second ply includes at least a first surface layer and a second surface layer. The first layer of the second ply ~~vhich faces the second layer of the first ply) is a cling layer which provides cling properties.
'7~he second layer of the second ply includes one or more corrosion inhibitors, and has relatively less or no cling compared to the first layer of the second ply. In a further embodiment, the first ply also includes at least a first s~xrf~ce layer and a second surface layer. 'The second layer of the first ply is a cling layer which provides cling properties. 'The first layer of the first ply tray have less or no cling properties compared to the second layer of the first ply.
In addition to the first and second surface :layers described above, the first ply and/or the second ply rnay include one or more core layers which do not have fTW-13896 4 Ilclb Y
an exposed surface. The core layers) may be structural layers) which provide added strength to tile first andlor second ply of the cling film system. The core layers) may also be relatively low cost bulk layers which reduce the overall material cost of the first and/or second ply.
During wrapping of an article, the first and second plies of the cling film system are applied to the article in a partially overlapping fashion so that the highest cling {second) surface of the first ply engages the highest cling (first) surface of the second ply, causing the engaged regions of the two plie;~ to cling together particularly well. Desirably, the second surface of the fret ply includes at least one region IO engaging the first surface of the second ply, and at least orJe adjacent region not engaging the same first surface of the second ply. I3esirably, the first surface of the second ply includes at Least one region engaging the second surface of the first ply, and at least one region not engaging the same second surface of the first ply.
While heat may be applied to facilitate bonding, no heat is required to cause the f rst and I5 second plies to cling together in the overlapping regions.
The cling film system may desibly be wrapped around an article in a spiral or undulating fashion, so that the same continuous cling film system passes around the article as a first wrap, second wrap, third wrap, ctc., around the article. 'The second wrap of the cling film systerrq around the article partially overlaps the first 2~ wrap, the third wrap partially overlaps the second wrap, and so on. Again, the first and second plies of the cling filr~r system partially overlap so that the highest cling ITW-13896 ~ I/clb (seconds surface of the first ply of ~. particular wrap (e.g. the second wrap) engages the highest cling (first) surface of the second ply of the same (e.g. second) wrap. 'the second surface of the first ply incla~des a region engaging the first surface of the second ply of the same (e.g. second) wrap, and a region not engaging the sarrle first surface of the second ply of the same wrap, the latter er~gagxr~g the first surface of the second ply of the in~media.tely p~°eGeding (e.g. first) wrap. 'fhe first surface of the second ply of the same (e.g. second) wrap includes a region engaging the second surface of the first ply of the same wrap, and a region not engaging the second surface of the first ply of the same v~~rap, the latter engaging the second surface of the first ply of the next subsequent (e.g. third) wrap.
With the foregoing in mind, it is a feature and advantage of the invention to provide an irr~proved cling f lm system wl.~ich provides improved cling properties as well as corrosion resistance, is relatively inexpensive to manufacture, and provides improved toughness and puncture resistance.
B EF I~ESCRIPT~~hi ~F TITS I3I~ ~t~S
FiG. 1 is a top plan view of a cling film system according to the invention.
FIG. 2 is a side view of a first e~bodigr~ent of a cling flrn system according to F1G. 1.
FIG. 2(a) schematically illustrates in section, how the cling film system of FIG. 2 may appear when wrapped onto an article or package of articles.
IT'W-13 ~9b 6 I/clb FICA. 3 is a side view of one preferred embodiment of a cling fllrr~
system.
FICi. 4 scltea~,atically illustrates a process useful for joining two plies of the clang film system together.
~E'~'A~LEI~IES~PT~~I'~ ~F '~'~
PSENT~Y p FE D ~li~I3~I ~'TS
IZefernng to dig. l, a cling elm system i0 of the invention includes a first pIy 20 and a second ply 30. The first ply 20 includes a non-overlapping portion 22 and an overlapping portion 24 which ovf;rlaps with the second ply. The second ply 30 includes a non-overlapping portion 32 and an overlapping portion 34 which overlaps with the first ply. For purposes of this in'Tentio~a, th.e terra "ply9' refers to a separately formed film. 'fine first and second plies 20 and 30 tray be formed using separate extrusion lines, or xnay be formed at different tin~aes using the same extrusion line; or may be formed simultaneously on the same extrusion li~ae at different positions on the bubble or web. The extrusion lines) may be blown film, cast film, or one of each.
The overlapping portions 24 and 34 represent the area over which the first ply 20 and the second ply 30 are joined and cling together. The overlapping portions 24 and 34 should have a width of about 2-86 inches, suitably about 5-inches. Each overlapping portion should constitute about 40-9~ percent of the width of the respective ply, desirably about 60-90 percent of the width of the respective ply.
ITVJ-1386 7 Ilclb l Referring to Fig. 2, the first p'y 20 has a i~~°st surface 26 which does riot engage the second ply 30., arid a second surface 28 which engages the second ply 30 over part of its area. The second surface 28 is a cling surface. F or purposes of this invention, the terra "cling surface" is defined as a surface with cling of at least 100 grams to itself, when measured using unstretched film according to AS'fllVII
I75458.
1 he second ply 30 has a first surface 36 which is a cling surface, and a second surface 38 which can be a non-cling surface. The first surface 36 engages the first ply 20 over part of its area.
In the embodiment of Fig. 2, fihe second "c;ling" surface 28 of the first ply 20 includes an entire inner side of the first ply 20, and only a portion of surface 28 of first ply 20 engages second ply 3U. Similarly, the first "cling" surface 36 of second ply 30 includes an entire outer side of second ply 36, and only a portion of surface 36 engages first ply 20.
'The first ply 20 may be composed of a single layer, formed of a cling material. ~ltematively, the first ply 20 may include two or more layers, provided that the layer which provides the second "cling" surface 28 is formed of a cling material.
In the embodiment of Fig. 2, the first ply 20 includes two layers 23 and 25 coextruded together. The layer 23, which has no contact with the second ply 30, may be a cling layer (i.e. a layer which provides a "cling surface" as defined above) or desirably a non-cling Iayer (i.e. a layer which does not provide a "cling surface" as defined above).
ITS-13896 8 I/clb For instance, ~:he layer 23 may be a non-c%ling layer which includes slip additives, antiblock additives, or the like which irrupar~ non-clung properties, in addition to an olefin homopolyrner or copolymer. The polymer used in the non-cling layer 23 may be low density polyethylene, linear low density polyethylene, or high S density polyethylene having a density of about 0.910-0.965 grams/cm3, desirably about 0.925-0.945 grarns/crn3, or a combination thereof: This ethylene polymer may have a melt index { 190 ° C, AST1VI ~ 1238) of about 0.0 5-10 gramsl l 0 min, desirably about 0.5-3.5 grarns/10 min V~r'hen the polymer is linear low density polyethylene, the alpha-olefin comonomer may have 3-12 carbons, ~aesirabiy 4-8 carbons. The polymer may also be a polypropylene homopolymer or propylene-ethylene copolymer containing less than about 10~'~o by weight etloylene, having a density of about t3.8 75-0.900 grams/cm', or a combination thereof. 'fhe propyle~~e polymer may brave a melt flow rate (230 ° C, ~.STNI h 12.38) of about 0.5-15 gramsf 10 rnir~, desirably about 2-10 gramsll0 rain. The polymer{s) used in fihe non-cling layer 23 nxay be prepared using a Ziegler-Natta catalyst, a single-site {e.g. metallocene) catalyst, or a chromium catalyst. In addition to slip and.~or antiblock additives, the layer 23 may include stabilizers, catalyst neutralizers, process aids, ultraviolet inhibitors and blockersg colorants, antistatic agents and other special purpose additives..
The second layer 2S of first ply 20 in Fig. 2 is a cling layer. ~, cling layer is any layer having a cling surface as defined above. Cling layers may include an ethylene-alpha olefin copolyrrrer plastomer, wherein the alpha-olefin has 3-IT~W-13896 9 Ilclb carbons, desirably 4-8 carbons. Suitable plastomers have a density of about 0.850-0.90 grams/cm3, and typically have a higher content o:~'alpha-olefin coinonomer than linear lour density polyethylene. Suitable plastomers have a melt index (190°C, ASTM I~ 1238) of about 0.1-10 grams/10 min., desirably about 0.6-6.0 grams/10 min.
Suitable plastomers rnay be prepared using a single-site (e.g. mctallocene) catalyst, and may also be prepared using a ~iegier-Natta or chrorniu~n catalyst. The plastorner may be used alone in the cling layer 25, or in combination with linear low density polyethylene andlor low density polyethylene, either having a density of shout 0.891-0.925 grams/cm3. Other pol~nners useful in cling layers, which may be used alone or in combination ~,rith a plastomer, include ethylene-vinyl acetate, ethylene methyl acrylate, ethylene ethyl acr'ylate, ethylene-propylene copolymers (especially those containing I0-90% by weight ethylene and 10-90% by weight propylene), and polyethylene homopolymers and copolyners blended with polyisobutylene, as well as combinations of the foregoing. Cling layers are preferably devoid of migratory additives, volatile corrosion inhibitors and other anti-cling materials, but may include stabilizers, antioxidants, catalyst neutralizers, processing aids and the like. In the embodiment of Fig. 2, at least the second layer 25 of first: ply 20 is a cling layer. The first layer 23 may be a cling layer or a non-cling layer, as described above.
'adhere cling and non-cling layers are employed, the cling layer should constitute about 5-20%
of the ply thicl~ness, desirably about 5-10% of the ply thickness.
ITW-13896 10 Ilclb In the embodiment of Fig. 2, the second ply 30 includes three layers 33, 35 and 37 coextruded together. The first layer 33 provides the first surface 36 which is a cling surface. Thus, the first layer 33 is a cling layer, and may have the same composition or range of compositions described above for the cling layer 25 of the first ply 20 in Fig. 2. The first Iayer 33 may constitute about 5-20% of the total thickness of the second ply 30, desirably about 5-I O% of the total thickness.
The second i.ayer 35 of the second ply 30 is a core layer in the embodiment of Fig. 2, and has no exposed surface. The second layer 3 5 need not have cling properties, and desirably includes a structural andlor bulls (cost saving) polymer or polymer combination. Suitable polymers for the second layer 35 include low density polyethylene, Iinear love density polyethylene or high density polyethylene having a density of about 0.910-0.965 grams/cm3, desirably about 0.910-0.945 gramslcm3, or a combination thereof. This ethylene polymer may have a melt index ( 190 ° ~, AS'Tl~I I~ I23 8) of about 0.05- I 0 grams/ 10 min., desirably about 0.5-3. 5 grams/l0min. The polymer may also be a polypropylene homopolymer or propylene-ethylene copolymer containing up to about 10% by weight ethylene, having a density of about 0.875-0.900 grams/crn3, or a combination thereof 'The propylene polyrrner may have a melt flow rate (L30°~, ASTIVI I)1~38) of about X0.5-15 grams/l0min., desirably about 2-10 grams/I0 min. The second layer 35 rnay also include stabilizers, Z0 catalyst neutralizers, and other conventional additives. Layer 35 may also contain one or more migrating volatile corrosion inhibitors, and may act as a reservoir which ITVJ-13896 I I Ilclb allows these additives to slowly migrate to the wrapped article to prevent corrosion.
The second layer 35 may constitute about _'>-90% of th.e total thickness of the second ply 30, desirably about f0-)0% of the total thickness.
'The third layer 37 ofthe seco~~d ply 30 is a surface layer which faces the article being wrapped. The third layer 3'7 may be a non-cling layer and nay be based on polymers the sagne or similar to those described for the second (core) layer 35.
Additionally, the third layer 37 may be a corrosion-inhibiting layer which contains about 0.5-20% by weight of one or more volatile corrosion inhibitors, desirably in master batches whose acti~Te ingredients :migrate toward the article and provide corrosion resistance. When present in a master batch, the volatile corrosion inhibitor master batch desirably constitutes about 0.5-15°lo by weight of the third layer 3'~. The third layer :~~ may constitute about 5-90% of'the total thickness of the second ply 30, desirably about ~-10% of the thickness.
The desired amount of volatile corrosion inhibitor depends on the amount of corrosion resistance needed and the type of volatnle corrosion inhibitor used. Suitable volatile corrosion inhibitors include inorganic nitrites, molybdates, carbonates, nitrogen-containing organic compounds, and combinations thereof Examples include sodium nitrite, dicyclohexylamine, monocyclohexylamine, triamines, triazoles such as benzotriazole and tolytriazole, combinations of organic amines and salts of ~.veak volatile acids, and other combinations of the foregoing.
1TW-13896 12 l/clb carious other modifications in the number of layers in each ply, the layer thicknesses, and the number ofplies are considered to be within the scope of this invention. For instance, the first and second plies 20 and 3(3 may each contain two layers, may each contain tlzz°ee layers, rnay each contain four 3.ayers, or either or both may contain any number of layers which i s most suitable for the application.
Ntore than two plies desirably having different compositions may alsa be employed in the cling film system. .Any two plies are considered to have different compositions if any layer in the f rst ply has a different composition andJor thicl~ness than a corresponding layer in the second ply, with layers counted from the top down in both plies, and/or if the two plies have different numbers of layers. The total thickness of each ply may vary depending on the end use. Each ply may have a total thickness of about 5-25~?
microns, suitably about 8-12~ microns, desirably about ~ 5-~0 microns.
In one embodiment, a three-ply str~zcture rnay be provided in which the first and second (outer) plies have facing cling layers and a third ply provided between them is a reinforcing mesh or scrim that need not have cling properties. The mesh or scrim has large enough openings that the first and second ;plies can interface and cling to each other through the openings in the third ply. The third ply provides added strength, and does not impede the stretching of the first and second plies due to the flexibility of the mesh or scrim structure.
2fl FICi. 3 illustrates a preferred embodiment of the cling film system 10 in which the first ply 120 and the second ply 1 a0 each have f ve layers. The first ply ITW-13896 13 I/clb I20 includes layers I2I, 122, I23, 124 and 125. The second ply 130 includes layers i 31, 132, I33, I34 and 135. The first layer 121 of the first ply 120 is a non-cling skin layer which may be formed from any of the non-cling polymers described above.
In one embodiment, the layer I2I is forFned of I~~V~E~ 2027A from the IJow Cherrxical Coe 'This polyrraer is a linear anedium density polyethylene having a density of about 0.94I grams/cm3 and a melt index of about 4Ø 'This polymer is are ethylene-octane copolymer prepared using a Ziegler-Natta catalyst. The layer I21 preferably constitutes about 10% of the thickness of the ply i 20.
The second and fourth Iayers 122 and 124 of the first ply 120 are sub-1 O skin layers which may be formed of polymers having high strength. These polymers may be non-cling polymers, Non-cling polymers as described. above, yet which are formed using single-site catalysts, a:e particularly suitable. In one embodiment, the Iayers I22 and 124 are formed using E~CEEI> 351 frorrl the Exxon-IVIobiI.
Chemical Co. This polyaner has a density of about 0.9 i ~ grarns/cm~ and a melt index of about 1 S 3.5. This polymer is an ethylene-hexane copolyaner prepared using a metallocene catalyst. Layers 122 and I2~ preferably each constitute about 20% of the thickness of the first ply I20.
The third (middle) layer of the first ply 120 may be formed using any of the non-cling polymers described above. In one embodiment, the layer 123 is 20 formed using I~~WLEX I3SE-1003 from the I~ow Chemical Co. This polymer is a linear lo~,v density polyethylene having a density of about 0.91 g gratns/crn3 and a melt ITW-i3~96 14 I/clb index of 2.3. This polymer is an ethylene-hexane c~poly~ner prepared using a ~iegler-I~atta catalyst. The third layer 223 preferably constitutes about 40% of the thickness of the first ply 120.
The fifth layer 12S of the ~=arst ply 120 is a cling skin layer. The layer 125 may be formed using any of the cling polymers described above. In one embodiment, the layer 1:,5 is formed using AFFI~.hTIT'~' I~C8852 frv~n the I~ow Chemical ~o. This polymer is an ethylene-octane copolymer plastomer haying a density of about 0.875 grarras/cm3 and a melt index of about 3.0, and is prepared using a constrained geometry single-site catalyst. The fifth layer 1:75 preferably constitutes about 10% of the thickness of the first ply 120.
Each of the layers 12I-125 nay includf; ingredients in addition to the s rated polymers. ~ther ingredients may include stabilizers, catalyst neutralizers, recycled edge trim, and other polymers and ingredients in amounts that do not ianpair or overcome the fiznctions and purposes of each of the layers.
S The first layer 131 ofthe second ply 130 is a cling skin layer which may be formed using any of the cling polymers described above. In one ernbodin~ent, the layer 131 is formed using ~'FII'~TIT'Y I~C8852 from the I~ow C:hernical Co.
The first layer 131 preferably constitutes about 10% of the thyckr~ess of the second ply 130.
The second and fourth layers 132 and 134 ofthe second ply 130 are sub-2 0 skin layers which rnay be formed of polymers having high strength. These polymers may be non-cling polymers. ion-cling poly~~ners as described above, yet which are ITW-13 8 96 15 I/clb formed using single-site catalysts, are particularly suitable. In one embodiment, the layers 132 and 134 are formed using E~CEEI) 3518 fre~ll~~ the ~~~n-Mobil Chemical Co. Layers 132 and 134 preferably each constitute abort 20% of the thickness of the second ply 130.
The third (middle) layer 133 ofthe second ply 130 maybe formed using any of the non-cling polymers described above. In one embodiment, the layer 133 is formed using D0~7LEX ~I'~lj-1003 from the Dow Chemical Co. 'The third layer preferably constitutes about 40% of the thickness of the second ply 130.
The fifth layer 135 of the second ply 130 is a non-cling skin layer.
Layer 135 may be formed using any of the non-cling polymers described above, and may also include a volatile corrosion inhibitor as described above, In one embodiment, skin layer i3~ is formed using DO~i,E~ 202'~A from the Dow Chemical Co. Desirably, the; skin layer includes 94 percent by weight DO~LE~
2027A blended with 6 percent by weight of a volatile corrosion inhibitor masterbatch.
I 5 The components may be dry blended before or upon entering the extruder.
The layer 1~5 preferably constitutes about 10% of the thickness of the second ply I30.
Each of the layers 131-135 may include ingredients in addition to the stated polymers. Other ingredients may include stabilizers, catalyst neutralizers, recycled edge trim, and other polymers and ingredients in amounts that do not impair or overcome the functions and purposes of each of the layers.
IT~T-13 8 9 s 16 I/clb The first and sec~nd plies 20, 120 and 30, 130 shown in flee cling f lm system of Figs. 2 and 3 may be independently prepared using any suitable film-forming technique including cast film coextrusion, blown film coexta~xsion, or a combination of both, as well as other techniques. Each ply is extruded as an elongated film strip having a width in the horizontal direction of the drawings, a thickness in the vertical direction of the drawings, and a length which may be substantially endless, in the direction perpendicular to the drawings. After extrusion, the separate plies 20 and 30, or 1~0 and 130 may be jouned together in overlapping fashion as shown in Figs. 2 and 3, either before or during wrapping. for instance, the 1 D first and second plies rnay be j oined together as shown and stored on the same wound-up roll for subsequent use. 'The joinirpmg of the plies may be accomplished by passing the plies 20 and 30, or 120 and 130, with overlapping portions between nip rollers at room temperature (50-130°T'~ or under heat. Alternatively, the first and second plies may be stored on separate wound-up rolls, and later joined during wrapping of an article.
A wide variety of articles may be wrapped using the cling frlsystem 10 of the invention. Examples of articles to be wrapped include without lxrtiitation steel coils and other metal objects, rows and skids of plastic bottles and other items, large bundles of extruded pieces, and the like. ~JVhere the article or package of articles 2f~ to be wrapped is large, long a~ad/or tall, it is desirable to apply the first and second ff~7-13896 l 7 Ilclb plies in an alternating, desirably spiral (u:~dulatir~g) pattern of first ply, second ply, first ply, second ply and so on, until the article or package is completely covered.
Referring to Fig. 2(a), there are various ways to achieve the alternating pattern of first ply 20, second ply 30, first ply 20, seco:r~d ply 30 and so on, along the length or width of an article or package. ~ne way, which is generally preferred, is to wrap a single pair of cling film plies 20 and 30 having a continuous or very long length, around the article or package in a spiral or undulating fashion. The spiral or undulating pattern is preferred because it eliminates the need to seal multiple pairs of plies, i.e., the single pair need only be sealed at both ends. The mating cling surfaces of the first ply 20 and second ply 30 are generally capable of clinging to each other at normal room or storage or processing temperatures of about 50-Z30°F, desirably about b0-90°F. If desired, heat may be applied to reinforce the seals at temperatures below or up to about 250 ° F, so as to soften the mating layers of the first anal second plies without melting them.
l 5 The alternating arrangement of first and second plies in Fig. 2(a) would result frown the use of the cling film system 10 shown do Fig. 2. Fig. 2(a) shows a schematic sectional view of a continuous cling film as it ~~ay appear on one surface of an article that has been wrapped in a spiral (undu.lating) fashion. The same continuous cling film system 10 passes around the article as a f rst wrap or undulation lOl~, a second wrap or undulation 10I3, a third wrap or undulation IOC, and so on.
The second wrap 10I~ of the cling film system around the article partially overlaps the IT'S-13896 1 ~ I/clb first wrap 1~A, and the third wrap lOC partially overlaps the second wrap 10E.
Each of the wraps 1 OA, 1013, I0C and so on, includes a section of the f rst ply 20 and a section of the second ply 30. Again, the first and second plies of the cling film system partially overlap so that the highest cling (second) surfhce 28 of the first ply 20 of a S particular wrap (e.g. the second wrap I0~) engages the highest cling {first) surface 36 of the second ply of the same {e.g. second) wrap. The second surface 28 of the first ply includes a region engaging the first surface 36 of the secorxd ply of the same {e.g.
second) wrap, and a region not engaging the same first surface of the second ply of the same wrap, the latter engaging the first surface 36 of the second ply of the imanediately preceding wrap (e.g. the first wrap 10A). The nrst surface 36 of the second ply of the same (e.g. second) wrap includes a region engaging the second surface 28 of the f rst ply of the same (e.g. second) wrap, and a region not engaging the second surface of the first ply of the sarr~e wrap, the latter engaging the second surface 28 of the first ply of the next subsequent wrap {e.g. the third wrap l OC).
1 S Fig. ~ schematically illustrates an apparatus that can be used to unwind and join the first and second plies 20 and 30 of the cling i.rlrn system 10, in a partially overlapping fashion. First ply 20 may be supplied from roll 108 or an extruder, and second ply 30 may be supplied from roll 110 or an extruder, with one or both rolls mounted with respect to an inlet frame 106. First ply 20 and second ply 30 are co~tnbined so that they partially overlap, and the combined cling film system 10 is passed over rollers 131, 13.~ and 112 under tension. T'he cling film system 10 is fI'~rV-13896 19 I/clb passed between a first nip defined by small roller 11 ~ and large roller I f 5, and a second nip defined by large roller 115 and small rotler~ I l i", t:~e rollers 113, 115 and 117 being mounted to a pr~aster frame 114. surface 125 of roller P 15 rnay be unheated, or may be heated to below the melting temperature of the adjacent contact layer of cling lilm system I0. The cling film system 10 then passes over guide rollers 120 and 121, and can be abound on a core held in place on shaft 107 during winding, and then stored in roll form on roll 122.
While the embodiments of the invention described herein are presently preferred, various modifications and irnpro~ements can be made without departing ~ 0 from the spirit and scope of the invention. The scope of the invention is indicated by the appended claims, and all changes that fall within tl~e meaning and range of equivalents are intended to be embraced therein.
ITVd-13 896 20 llclb
I~I_,~~' 'T~' IhI'TI~i~
This in'Tention is directed to an improved cling falm system, useful for wrapping steel coils and other articles in a spiral fashion.
~A~~I~CI D ~F rE II~Vh,IV'TI~N
Various single layer and multiple layer cling films have been used for wrapping steel coils and other articles. Cling films are typically based on polyethylene homopolymers or copolymers including, without limitation, low density polyethylene, linear low density polyethylene, ethylene vinyl acetate and the like. In i0 addition to the polymer co~~ponents, these films typically include a balance of additives which are intended to improve c:~ing, and additives employed for other purposes which may have an undesirable anti-cling effect.
A cling filrr~ ~rrust have the obi ity to stick or cling to itself, or to other films having the same composition. Cane coA-zventional cling falm is based on linear low density polyethylene modified with a cling additive, such as polyisobutylene, a volatile corrosion inhibitor, such as sodiurr~ nitrite, as well as other chemicals described below that bloom to the surface and deposit on the steel surface to inhibit corrosion. The corrosion inhibiting chemicals tend to diminish or eliminate the cling of the linear low density polyethylene film. 'Tl~e polyisobutylene restores the cling to 2~ the f lm, so that the film will cling or stick to itself during wrapping of an article.
ITVV-13 X96 2 I/clb d Multiple layer films have also been developed, having very high cling properties in an outer facing layer of the film and corrosion inhibiting additives in an inner facing layer. The corrosion inhibiting additives care thus readily migrate to the article being wrapped. 'fhe very high cling properties of the outer facing layer tend to offset the low cling properties of the inner facing layer, so that the two surfaces adequately cling together daring wrapping.
~ther cling films include volatile corm>sic~n inhibitors applied as a coating in stripes or other spaced apart patterns. ~'he areas on the f~lnr~
away from the stripes are devoid of these additives, allowi~ag opposing film surfaces to cling together lfl during wrapping. These cling dlr.'s arE; relatively complex and expensive to manufacture.
Another difficulty encountered with prior cling ~lrr~s (both single layer and mufti-layer) is that they nay puncture and tear whe~~ exposed to the sharp edges of steel coils or other articles being wrapped. Thus, tlT~ere is a need or desire for a cling f lm system which a) provides improved cling properties while aiding corrosion resistance, b) is relatively inexpensive to anufactc~.re, arid c) has unproved toughness and puncture resistance.
SIJI''Sl C~T~I~NN'I'I~N
The present invention is directed to a cling film sy,stern including at least 2~ two plies. The first ply has a first surface and a second surface, the second ply has a first surface and a second surface, and the second surface of the first ply faces and IT~N-13896 3 Ilclb l partially overlaps the first surface of the second ply. 'The first ply and the second ply rnay have different compos;dons fAom each. other. T'he second surface ~f the first ply and the first surface of the second ply have cling properties.
~'he first ply and second ply may be formed separately, as separate films, and brought together before or during wrapping of the article so that the second surface of the first ply partially overlaps the first surface; of the second ply. 'T he first ply and the second ply may each have.a single layer, or multiple layers, and need not have the carne number of layers. ~'he first ply and the second ply may each be formed by cast or blown film extrusion or coextr~asion, and need not be formed by the same ~ 0 process.
In one embodiment, the second ply includes at least a first surface layer and a second surface layer. The first layer of the second ply ~~vhich faces the second layer of the first ply) is a cling layer which provides cling properties.
'7~he second layer of the second ply includes one or more corrosion inhibitors, and has relatively less or no cling compared to the first layer of the second ply. In a further embodiment, the first ply also includes at least a first s~xrf~ce layer and a second surface layer. 'The second layer of the first ply is a cling layer which provides cling properties. 'The first layer of the first ply tray have less or no cling properties compared to the second layer of the first ply.
In addition to the first and second surface :layers described above, the first ply and/or the second ply rnay include one or more core layers which do not have fTW-13896 4 Ilclb Y
an exposed surface. The core layers) may be structural layers) which provide added strength to tile first andlor second ply of the cling film system. The core layers) may also be relatively low cost bulk layers which reduce the overall material cost of the first and/or second ply.
During wrapping of an article, the first and second plies of the cling film system are applied to the article in a partially overlapping fashion so that the highest cling {second) surface of the first ply engages the highest cling (first) surface of the second ply, causing the engaged regions of the two plie;~ to cling together particularly well. Desirably, the second surface of the fret ply includes at least one region IO engaging the first surface of the second ply, and at least orJe adjacent region not engaging the same first surface of the second ply. I3esirably, the first surface of the second ply includes at Least one region engaging the second surface of the first ply, and at least one region not engaging the same second surface of the first ply.
While heat may be applied to facilitate bonding, no heat is required to cause the f rst and I5 second plies to cling together in the overlapping regions.
The cling film system may desibly be wrapped around an article in a spiral or undulating fashion, so that the same continuous cling film system passes around the article as a first wrap, second wrap, third wrap, ctc., around the article. 'The second wrap of the cling film systerrq around the article partially overlaps the first 2~ wrap, the third wrap partially overlaps the second wrap, and so on. Again, the first and second plies of the cling filr~r system partially overlap so that the highest cling ITW-13896 ~ I/clb (seconds surface of the first ply of ~. particular wrap (e.g. the second wrap) engages the highest cling (first) surface of the second ply of the same (e.g. second) wrap. 'the second surface of the first ply incla~des a region engaging the first surface of the second ply of the same (e.g. second) wrap, and a region not engaging the sarrle first surface of the second ply of the same wrap, the latter er~gagxr~g the first surface of the second ply of the in~media.tely p~°eGeding (e.g. first) wrap. 'fhe first surface of the second ply of the same (e.g. second) wrap includes a region engaging the second surface of the first ply of the same wrap, and a region not engaging the second surface of the first ply of the same v~~rap, the latter engaging the second surface of the first ply of the next subsequent (e.g. third) wrap.
With the foregoing in mind, it is a feature and advantage of the invention to provide an irr~proved cling f lm system wl.~ich provides improved cling properties as well as corrosion resistance, is relatively inexpensive to manufacture, and provides improved toughness and puncture resistance.
B EF I~ESCRIPT~~hi ~F TITS I3I~ ~t~S
FiG. 1 is a top plan view of a cling film system according to the invention.
FIG. 2 is a side view of a first e~bodigr~ent of a cling flrn system according to F1G. 1.
FIG. 2(a) schematically illustrates in section, how the cling film system of FIG. 2 may appear when wrapped onto an article or package of articles.
IT'W-13 ~9b 6 I/clb FICA. 3 is a side view of one preferred embodiment of a cling fllrr~
system.
FICi. 4 scltea~,atically illustrates a process useful for joining two plies of the clang film system together.
~E'~'A~LEI~IES~PT~~I'~ ~F '~'~
PSENT~Y p FE D ~li~I3~I ~'TS
IZefernng to dig. l, a cling elm system i0 of the invention includes a first pIy 20 and a second ply 30. The first ply 20 includes a non-overlapping portion 22 and an overlapping portion 24 which ovf;rlaps with the second ply. The second ply 30 includes a non-overlapping portion 32 and an overlapping portion 34 which overlaps with the first ply. For purposes of this in'Tentio~a, th.e terra "ply9' refers to a separately formed film. 'fine first and second plies 20 and 30 tray be formed using separate extrusion lines, or xnay be formed at different tin~aes using the same extrusion line; or may be formed simultaneously on the same extrusion li~ae at different positions on the bubble or web. The extrusion lines) may be blown film, cast film, or one of each.
The overlapping portions 24 and 34 represent the area over which the first ply 20 and the second ply 30 are joined and cling together. The overlapping portions 24 and 34 should have a width of about 2-86 inches, suitably about 5-inches. Each overlapping portion should constitute about 40-9~ percent of the width of the respective ply, desirably about 60-90 percent of the width of the respective ply.
ITVJ-1386 7 Ilclb l Referring to Fig. 2, the first p'y 20 has a i~~°st surface 26 which does riot engage the second ply 30., arid a second surface 28 which engages the second ply 30 over part of its area. The second surface 28 is a cling surface. F or purposes of this invention, the terra "cling surface" is defined as a surface with cling of at least 100 grams to itself, when measured using unstretched film according to AS'fllVII
I75458.
1 he second ply 30 has a first surface 36 which is a cling surface, and a second surface 38 which can be a non-cling surface. The first surface 36 engages the first ply 20 over part of its area.
In the embodiment of Fig. 2, fihe second "c;ling" surface 28 of the first ply 20 includes an entire inner side of the first ply 20, and only a portion of surface 28 of first ply 20 engages second ply 3U. Similarly, the first "cling" surface 36 of second ply 30 includes an entire outer side of second ply 36, and only a portion of surface 36 engages first ply 20.
'The first ply 20 may be composed of a single layer, formed of a cling material. ~ltematively, the first ply 20 may include two or more layers, provided that the layer which provides the second "cling" surface 28 is formed of a cling material.
In the embodiment of Fig. 2, the first ply 20 includes two layers 23 and 25 coextruded together. The layer 23, which has no contact with the second ply 30, may be a cling layer (i.e. a layer which provides a "cling surface" as defined above) or desirably a non-cling Iayer (i.e. a layer which does not provide a "cling surface" as defined above).
ITS-13896 8 I/clb For instance, ~:he layer 23 may be a non-c%ling layer which includes slip additives, antiblock additives, or the like which irrupar~ non-clung properties, in addition to an olefin homopolyrner or copolymer. The polymer used in the non-cling layer 23 may be low density polyethylene, linear low density polyethylene, or high S density polyethylene having a density of about 0.910-0.965 grams/cm3, desirably about 0.925-0.945 grarns/crn3, or a combination thereof: This ethylene polymer may have a melt index { 190 ° C, AST1VI ~ 1238) of about 0.0 5-10 gramsl l 0 min, desirably about 0.5-3.5 grarns/10 min V~r'hen the polymer is linear low density polyethylene, the alpha-olefin comonomer may have 3-12 carbons, ~aesirabiy 4-8 carbons. The polymer may also be a polypropylene homopolymer or propylene-ethylene copolymer containing less than about 10~'~o by weight etloylene, having a density of about t3.8 75-0.900 grams/cm', or a combination thereof. 'fhe propyle~~e polymer may brave a melt flow rate (230 ° C, ~.STNI h 12.38) of about 0.5-15 gramsf 10 rnir~, desirably about 2-10 gramsll0 rain. The polymer{s) used in fihe non-cling layer 23 nxay be prepared using a Ziegler-Natta catalyst, a single-site {e.g. metallocene) catalyst, or a chromium catalyst. In addition to slip and.~or antiblock additives, the layer 23 may include stabilizers, catalyst neutralizers, process aids, ultraviolet inhibitors and blockersg colorants, antistatic agents and other special purpose additives..
The second layer 2S of first ply 20 in Fig. 2 is a cling layer. ~, cling layer is any layer having a cling surface as defined above. Cling layers may include an ethylene-alpha olefin copolyrrrer plastomer, wherein the alpha-olefin has 3-IT~W-13896 9 Ilclb carbons, desirably 4-8 carbons. Suitable plastomers have a density of about 0.850-0.90 grams/cm3, and typically have a higher content o:~'alpha-olefin coinonomer than linear lour density polyethylene. Suitable plastomers have a melt index (190°C, ASTM I~ 1238) of about 0.1-10 grams/10 min., desirably about 0.6-6.0 grams/10 min.
Suitable plastomers rnay be prepared using a single-site (e.g. mctallocene) catalyst, and may also be prepared using a ~iegier-Natta or chrorniu~n catalyst. The plastorner may be used alone in the cling layer 25, or in combination with linear low density polyethylene andlor low density polyethylene, either having a density of shout 0.891-0.925 grams/cm3. Other pol~nners useful in cling layers, which may be used alone or in combination ~,rith a plastomer, include ethylene-vinyl acetate, ethylene methyl acrylate, ethylene ethyl acr'ylate, ethylene-propylene copolymers (especially those containing I0-90% by weight ethylene and 10-90% by weight propylene), and polyethylene homopolymers and copolyners blended with polyisobutylene, as well as combinations of the foregoing. Cling layers are preferably devoid of migratory additives, volatile corrosion inhibitors and other anti-cling materials, but may include stabilizers, antioxidants, catalyst neutralizers, processing aids and the like. In the embodiment of Fig. 2, at least the second layer 25 of first: ply 20 is a cling layer. The first layer 23 may be a cling layer or a non-cling layer, as described above.
'adhere cling and non-cling layers are employed, the cling layer should constitute about 5-20%
of the ply thicl~ness, desirably about 5-10% of the ply thickness.
ITW-13896 10 Ilclb In the embodiment of Fig. 2, the second ply 30 includes three layers 33, 35 and 37 coextruded together. The first layer 33 provides the first surface 36 which is a cling surface. Thus, the first layer 33 is a cling layer, and may have the same composition or range of compositions described above for the cling layer 25 of the first ply 20 in Fig. 2. The first Iayer 33 may constitute about 5-20% of the total thickness of the second ply 30, desirably about 5-I O% of the total thickness.
The second i.ayer 35 of the second ply 30 is a core layer in the embodiment of Fig. 2, and has no exposed surface. The second layer 3 5 need not have cling properties, and desirably includes a structural andlor bulls (cost saving) polymer or polymer combination. Suitable polymers for the second layer 35 include low density polyethylene, Iinear love density polyethylene or high density polyethylene having a density of about 0.910-0.965 grams/cm3, desirably about 0.910-0.945 gramslcm3, or a combination thereof. This ethylene polymer may have a melt index ( 190 ° ~, AS'Tl~I I~ I23 8) of about 0.05- I 0 grams/ 10 min., desirably about 0.5-3. 5 grams/l0min. The polymer may also be a polypropylene homopolymer or propylene-ethylene copolymer containing up to about 10% by weight ethylene, having a density of about 0.875-0.900 grams/crn3, or a combination thereof 'The propylene polyrrner may have a melt flow rate (L30°~, ASTIVI I)1~38) of about X0.5-15 grams/l0min., desirably about 2-10 grams/I0 min. The second layer 35 rnay also include stabilizers, Z0 catalyst neutralizers, and other conventional additives. Layer 35 may also contain one or more migrating volatile corrosion inhibitors, and may act as a reservoir which ITVJ-13896 I I Ilclb allows these additives to slowly migrate to the wrapped article to prevent corrosion.
The second layer 35 may constitute about _'>-90% of th.e total thickness of the second ply 30, desirably about f0-)0% of the total thickness.
'The third layer 37 ofthe seco~~d ply 30 is a surface layer which faces the article being wrapped. The third layer 3'7 may be a non-cling layer and nay be based on polymers the sagne or similar to those described for the second (core) layer 35.
Additionally, the third layer 37 may be a corrosion-inhibiting layer which contains about 0.5-20% by weight of one or more volatile corrosion inhibitors, desirably in master batches whose acti~Te ingredients :migrate toward the article and provide corrosion resistance. When present in a master batch, the volatile corrosion inhibitor master batch desirably constitutes about 0.5-15°lo by weight of the third layer 3'~. The third layer :~~ may constitute about 5-90% of'the total thickness of the second ply 30, desirably about ~-10% of the thickness.
The desired amount of volatile corrosion inhibitor depends on the amount of corrosion resistance needed and the type of volatnle corrosion inhibitor used. Suitable volatile corrosion inhibitors include inorganic nitrites, molybdates, carbonates, nitrogen-containing organic compounds, and combinations thereof Examples include sodium nitrite, dicyclohexylamine, monocyclohexylamine, triamines, triazoles such as benzotriazole and tolytriazole, combinations of organic amines and salts of ~.veak volatile acids, and other combinations of the foregoing.
1TW-13896 12 l/clb carious other modifications in the number of layers in each ply, the layer thicknesses, and the number ofplies are considered to be within the scope of this invention. For instance, the first and second plies 20 and 3(3 may each contain two layers, may each contain tlzz°ee layers, rnay each contain four 3.ayers, or either or both may contain any number of layers which i s most suitable for the application.
Ntore than two plies desirably having different compositions may alsa be employed in the cling film system. .Any two plies are considered to have different compositions if any layer in the f rst ply has a different composition andJor thicl~ness than a corresponding layer in the second ply, with layers counted from the top down in both plies, and/or if the two plies have different numbers of layers. The total thickness of each ply may vary depending on the end use. Each ply may have a total thickness of about 5-25~?
microns, suitably about 8-12~ microns, desirably about ~ 5-~0 microns.
In one embodiment, a three-ply str~zcture rnay be provided in which the first and second (outer) plies have facing cling layers and a third ply provided between them is a reinforcing mesh or scrim that need not have cling properties. The mesh or scrim has large enough openings that the first and second ;plies can interface and cling to each other through the openings in the third ply. The third ply provides added strength, and does not impede the stretching of the first and second plies due to the flexibility of the mesh or scrim structure.
2fl FICi. 3 illustrates a preferred embodiment of the cling film system 10 in which the first ply 120 and the second ply 1 a0 each have f ve layers. The first ply ITW-13896 13 I/clb I20 includes layers I2I, 122, I23, 124 and 125. The second ply 130 includes layers i 31, 132, I33, I34 and 135. The first layer 121 of the first ply 120 is a non-cling skin layer which may be formed from any of the non-cling polymers described above.
In one embodiment, the layer I2I is forFned of I~~V~E~ 2027A from the IJow Cherrxical Coe 'This polyrraer is a linear anedium density polyethylene having a density of about 0.94I grams/cm3 and a melt index of about 4Ø 'This polymer is are ethylene-octane copolymer prepared using a Ziegler-Natta catalyst. The layer I21 preferably constitutes about 10% of the thickness of the ply i 20.
The second and fourth Iayers 122 and 124 of the first ply 120 are sub-1 O skin layers which may be formed of polymers having high strength. These polymers may be non-cling polymers, Non-cling polymers as described. above, yet which are formed using single-site catalysts, a:e particularly suitable. In one embodiment, the Iayers I22 and 124 are formed using E~CEEI> 351 frorrl the Exxon-IVIobiI.
Chemical Co. This polyaner has a density of about 0.9 i ~ grarns/cm~ and a melt index of about 1 S 3.5. This polymer is an ethylene-hexane copolyaner prepared using a metallocene catalyst. Layers 122 and I2~ preferably each constitute about 20% of the thickness of the first ply I20.
The third (middle) layer of the first ply 120 may be formed using any of the non-cling polymers described above. In one embodiment, the layer 123 is 20 formed using I~~WLEX I3SE-1003 from the I~ow Chemical Co. This polymer is a linear lo~,v density polyethylene having a density of about 0.91 g gratns/crn3 and a melt ITW-i3~96 14 I/clb index of 2.3. This polymer is an ethylene-hexane c~poly~ner prepared using a ~iegler-I~atta catalyst. The third layer 223 preferably constitutes about 40% of the thickness of the first ply 120.
The fifth layer 12S of the ~=arst ply 120 is a cling skin layer. The layer 125 may be formed using any of the cling polymers described above. In one embodiment, the layer 1:,5 is formed using AFFI~.hTIT'~' I~C8852 frv~n the I~ow Chemical ~o. This polymer is an ethylene-octane copolymer plastomer haying a density of about 0.875 grarras/cm3 and a melt index of about 3.0, and is prepared using a constrained geometry single-site catalyst. The fifth layer 1:75 preferably constitutes about 10% of the thickness of the first ply 120.
Each of the layers 12I-125 nay includf; ingredients in addition to the s rated polymers. ~ther ingredients may include stabilizers, catalyst neutralizers, recycled edge trim, and other polymers and ingredients in amounts that do not ianpair or overcome the fiznctions and purposes of each of the layers.
S The first layer 131 ofthe second ply 130 is a cling skin layer which may be formed using any of the cling polymers described above. In one ernbodin~ent, the layer 131 is formed using ~'FII'~TIT'Y I~C8852 from the I~ow C:hernical Co.
The first layer 131 preferably constitutes about 10% of the thyckr~ess of the second ply 130.
The second and fourth layers 132 and 134 ofthe second ply 130 are sub-2 0 skin layers which rnay be formed of polymers having high strength. These polymers may be non-cling polymers. ion-cling poly~~ners as described above, yet which are ITW-13 8 96 15 I/clb formed using single-site catalysts, are particularly suitable. In one embodiment, the layers 132 and 134 are formed using E~CEEI) 3518 fre~ll~~ the ~~~n-Mobil Chemical Co. Layers 132 and 134 preferably each constitute abort 20% of the thickness of the second ply 130.
The third (middle) layer 133 ofthe second ply 130 maybe formed using any of the non-cling polymers described above. In one embodiment, the layer 133 is formed using D0~7LEX ~I'~lj-1003 from the Dow Chemical Co. 'The third layer preferably constitutes about 40% of the thickness of the second ply 130.
The fifth layer 135 of the second ply 130 is a non-cling skin layer.
Layer 135 may be formed using any of the non-cling polymers described above, and may also include a volatile corrosion inhibitor as described above, In one embodiment, skin layer i3~ is formed using DO~i,E~ 202'~A from the Dow Chemical Co. Desirably, the; skin layer includes 94 percent by weight DO~LE~
2027A blended with 6 percent by weight of a volatile corrosion inhibitor masterbatch.
I 5 The components may be dry blended before or upon entering the extruder.
The layer 1~5 preferably constitutes about 10% of the thickness of the second ply I30.
Each of the layers 131-135 may include ingredients in addition to the stated polymers. Other ingredients may include stabilizers, catalyst neutralizers, recycled edge trim, and other polymers and ingredients in amounts that do not impair or overcome the functions and purposes of each of the layers.
IT~T-13 8 9 s 16 I/clb The first and sec~nd plies 20, 120 and 30, 130 shown in flee cling f lm system of Figs. 2 and 3 may be independently prepared using any suitable film-forming technique including cast film coextrusion, blown film coexta~xsion, or a combination of both, as well as other techniques. Each ply is extruded as an elongated film strip having a width in the horizontal direction of the drawings, a thickness in the vertical direction of the drawings, and a length which may be substantially endless, in the direction perpendicular to the drawings. After extrusion, the separate plies 20 and 30, or 1~0 and 130 may be jouned together in overlapping fashion as shown in Figs. 2 and 3, either before or during wrapping. for instance, the 1 D first and second plies rnay be j oined together as shown and stored on the same wound-up roll for subsequent use. 'The joinirpmg of the plies may be accomplished by passing the plies 20 and 30, or 120 and 130, with overlapping portions between nip rollers at room temperature (50-130°T'~ or under heat. Alternatively, the first and second plies may be stored on separate wound-up rolls, and later joined during wrapping of an article.
A wide variety of articles may be wrapped using the cling frlsystem 10 of the invention. Examples of articles to be wrapped include without lxrtiitation steel coils and other metal objects, rows and skids of plastic bottles and other items, large bundles of extruded pieces, and the like. ~JVhere the article or package of articles 2f~ to be wrapped is large, long a~ad/or tall, it is desirable to apply the first and second ff~7-13896 l 7 Ilclb plies in an alternating, desirably spiral (u:~dulatir~g) pattern of first ply, second ply, first ply, second ply and so on, until the article or package is completely covered.
Referring to Fig. 2(a), there are various ways to achieve the alternating pattern of first ply 20, second ply 30, first ply 20, seco:r~d ply 30 and so on, along the length or width of an article or package. ~ne way, which is generally preferred, is to wrap a single pair of cling film plies 20 and 30 having a continuous or very long length, around the article or package in a spiral or undulating fashion. The spiral or undulating pattern is preferred because it eliminates the need to seal multiple pairs of plies, i.e., the single pair need only be sealed at both ends. The mating cling surfaces of the first ply 20 and second ply 30 are generally capable of clinging to each other at normal room or storage or processing temperatures of about 50-Z30°F, desirably about b0-90°F. If desired, heat may be applied to reinforce the seals at temperatures below or up to about 250 ° F, so as to soften the mating layers of the first anal second plies without melting them.
l 5 The alternating arrangement of first and second plies in Fig. 2(a) would result frown the use of the cling film system 10 shown do Fig. 2. Fig. 2(a) shows a schematic sectional view of a continuous cling film as it ~~ay appear on one surface of an article that has been wrapped in a spiral (undu.lating) fashion. The same continuous cling film system 10 passes around the article as a f rst wrap or undulation lOl~, a second wrap or undulation 10I3, a third wrap or undulation IOC, and so on.
The second wrap 10I~ of the cling film system around the article partially overlaps the IT'S-13896 1 ~ I/clb first wrap 1~A, and the third wrap lOC partially overlaps the second wrap 10E.
Each of the wraps 1 OA, 1013, I0C and so on, includes a section of the f rst ply 20 and a section of the second ply 30. Again, the first and second plies of the cling film system partially overlap so that the highest cling (second) surfhce 28 of the first ply 20 of a S particular wrap (e.g. the second wrap I0~) engages the highest cling {first) surface 36 of the second ply of the same {e.g. second) wrap. The second surface 28 of the first ply includes a region engaging the first surface 36 of the secorxd ply of the same {e.g.
second) wrap, and a region not engaging the same first surface of the second ply of the same wrap, the latter engaging the first surface 36 of the second ply of the imanediately preceding wrap (e.g. the first wrap 10A). The nrst surface 36 of the second ply of the same (e.g. second) wrap includes a region engaging the second surface 28 of the f rst ply of the same (e.g. second) wrap, and a region not engaging the second surface of the first ply of the sarr~e wrap, the latter engaging the second surface 28 of the first ply of the next subsequent wrap {e.g. the third wrap l OC).
1 S Fig. ~ schematically illustrates an apparatus that can be used to unwind and join the first and second plies 20 and 30 of the cling i.rlrn system 10, in a partially overlapping fashion. First ply 20 may be supplied from roll 108 or an extruder, and second ply 30 may be supplied from roll 110 or an extruder, with one or both rolls mounted with respect to an inlet frame 106. First ply 20 and second ply 30 are co~tnbined so that they partially overlap, and the combined cling film system 10 is passed over rollers 131, 13.~ and 112 under tension. T'he cling film system 10 is fI'~rV-13896 19 I/clb passed between a first nip defined by small roller 11 ~ and large roller I f 5, and a second nip defined by large roller 115 and small rotler~ I l i", t:~e rollers 113, 115 and 117 being mounted to a pr~aster frame 114. surface 125 of roller P 15 rnay be unheated, or may be heated to below the melting temperature of the adjacent contact layer of cling lilm system I0. The cling film system 10 then passes over guide rollers 120 and 121, and can be abound on a core held in place on shaft 107 during winding, and then stored in roll form on roll 122.
While the embodiments of the invention described herein are presently preferred, various modifications and irnpro~ements can be made without departing ~ 0 from the spirit and scope of the invention. The scope of the invention is indicated by the appended claims, and all changes that fall within tl~e meaning and range of equivalents are intended to be embraced therein.
ITVd-13 896 20 llclb
Claims (29)
1. A cling film system, comprising:
a first film ply including at least one cling layer; and a second film ply including at least one cling layer;
each of the first and second film plies including a first overlapping portion and a second portion;
the cling layer of the first film ply engaging the cling layer of the second film ply in the overlapping portion of the first film ply and in the overlapping portion of the second film ply.
a first film ply including at least one cling layer; and a second film ply including at least one cling layer;
each of the first and second film plies including a first overlapping portion and a second portion;
the cling layer of the first film ply engaging the cling layer of the second film ply in the overlapping portion of the first film ply and in the overlapping portion of the second film ply.
2. The cling film system of Claim 1, wherein the first film ply and the second film ply have different compositions.
3. The cling film system of Claim 1, wherein the cling layer in the first film ply comprises a polymer selected from ethylene-alpha olefin copolymer plastomers, ethylene vinyl acetate, ethylene methyl acrylate, ethylene ethyl acrylate, ethylene-propylene copolymers including about 10-90% by weight each of ethylene and propylene, polyisobutylene, blends of the foregoing with linear low density polyethylene, and combinations thereof.
4. The cling film system of Claim 3, wherein the cling layer in the first ply comprises an ethylene-alpha olefin copolymer plastomer having a density of about 0.85-0.89 grams/cm3.
5. The cling film system of Claim 1, wherein the cling layer in the second film ply comprises a polymer selected from ethylene-alpha olefin copolymer plastomers, ethylene vinyl acetate, ethylene methyl acrylate, ethylene ethyl acrylate, ethylene-propylene copolymers including about 10-90% by weight each of ethylene and propylene, polyisobutylene, blends of the foregoing with linear low density polyethylene, and combinations thereof.
6. The cling film system of Claim 5, wherein the cling layer in the second film ply comprises an ethylene-alpha olefin copolymer plastomer having a density of about 0.85-0.89 grams/cm3.
7. The cling film system of Claim 1, wherein the first film ply further comprises a non-cling layer.~
8. The cling film system of Claim 7, wherein the non-cling layer in the first film ply comprises a polymer selected from low density polyethylene, linear low density polyethylene, high density polyethylene, polypropylene, propylene-ethylene copolymers including less than about 10% by weight ethylene, and combinations thereof.
9. The cling film system of Claim 1, wherein the second film ply further comprises a non-cling layer.
10. The cling film system of Claim 9, wherein the non-cling layer in the second film ply comprises a polymer selected from low density polyethylene, linear low density polyethylene, high density polyethylene, polypropylene, propylene-ethylene copolymers including less than about 10% by weight ethylene, and combinations thereof.
11. The cling film system of Claim 9, wherein the non-cling layer in the second film ply comprises a volatile corrosion inhibitor.
12. A cling film system, comprising:
a first multilayer film ply including a cling layer; and a second multilayer film ply including a cling layer and a corrosion-inhibiting layer;
each of the first and second film plies including a first overlapping portion and a second portion;
the cling layer of the first film ply engaging the cling layer of the second film ply in the overlapping portion of the first film ply and in the overlapping portion of the second film ply.
a first multilayer film ply including a cling layer; and a second multilayer film ply including a cling layer and a corrosion-inhibiting layer;
each of the first and second film plies including a first overlapping portion and a second portion;
the cling layer of the first film ply engaging the cling layer of the second film ply in the overlapping portion of the first film ply and in the overlapping portion of the second film ply.
13. The cling film system of Claim 12, wherein each of the first and second film plies includes only two layers.
14. The cling film system of Claim 12, wherein one of the first and second film plies includes three layers.
15. The cling film system of Claim 12, wherein each of the first and second film plies includes three layers.
16. The cling film system of Claim 12, wherein one of the first and second film plies includes four layers.
17. The cling film system of Claim 12, wherein each of the first and second film plies includes four layers.
18. The cling film system of Claim 12, wherein ore of the first and second film plies includes five layers.
19. The cling film system of Claim 12, wherein each of the first and second film plies includes five layers.
20. The cling film system of Claim 12, wherein the cling layer in the first film ply comprises a polymer selected from ethylene-alpha olefin copolymer plastomers, ethylene vinyl acetate, ethylene methyl acrylate, ethylene ethyl acrylate, ethylene-propylene copolymers including about 10-90% by weight each of ethylene and propylene, polyisobutylene, blends of the foregoing with linear love density polyethylene, and combinations thereof.
21. The cling film system of Claim 20, wherein the cling layer in the first ply comprises an ethylene-alpha olefin copolymer plastomer having a density of about 0.85-0.89 grams/cm3.
22. The cling film system of Claim 12, wherein the cling layer in the second film ply comprises a polymer selected from ethylene-alpha olefin copolymer plastomers, ethylene vinyl acetate, ethylene methyl acrylate, ethylene ethyl acrylate, ethylene-propylene copolymers including about 10-90% by weight each of ethylene and propylene, polyisobutylene, blends of the foregoing with linear low density polyethylene, and combinations thereof.
23. The cling film system of Claim 22, wherein the cling layer in the second film ply comprises an ethylene-alpha olefin copolymer plastomer having a density of about 0.85-0.89 grams/cm3.
24. The cling film system of Claim 12, wherein the corrosion-inhibiting layer in the second film ply comprises a polymer selected from low density polyethylene, linear low density polyethylene, high density polyethylene, polypropylene, propylene-ethylene copolymers including less than about 10% by weight ethylene, and combinations thereof
25. The cling film system of Claim 24, wherein the corrosion-inhibiting layer in the second film ply further comprises a volatile corrosion inhibitor selected from inorganic nitrites, molybdates, carbonates, nitrogen-containing organic compounds, and combinations thereof.
26 26. The cling film system of Claim 25, wherein the volatile corrosion inhibitor comprises a compound selected from sodium nitrite, dicyclohexylamine, monocyclohexylamine, triamines, triazoles, and combinations thereof.
27. The cling film system of Claim 25, wherein the volatile corrosion inhibitor comprises sodium nitrite.
28. A wrapped article or package, comprising:
one or more articles; and a wrapper including a cling film system;
the cling film system including a first film ply including a cling layer and a second film ply including a cling layer;
each of the first and second film plies including an overlapping portion and a second portion;
the cling layer of the first film ply engaging the cling layer of the second film ply in the overlapping portion of the first film ply and in the overlapping portion of the second film ply;
the wrapper including an alternating sequence of first and second film plies.
one or more articles; and a wrapper including a cling film system;
the cling film system including a first film ply including a cling layer and a second film ply including a cling layer;
each of the first and second film plies including an overlapping portion and a second portion;
the cling layer of the first film ply engaging the cling layer of the second film ply in the overlapping portion of the first film ply and in the overlapping portion of the second film ply;
the wrapper including an alternating sequence of first and second film plies.
29. The wrapped article of Claim 26, wherein the wrapper comprises the cling film system arranged in a spiral or undulating fashion.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US10/354,448 | 2003-01-30 | ||
| US10/354,448 US6942909B2 (en) | 2003-01-30 | 2003-01-30 | Wrapping films with mating cling strips |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2453748A1 true CA2453748A1 (en) | 2004-07-30 |
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ID=32655549
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2453748 Abandoned CA2453748A1 (en) | 2003-01-30 | 2003-12-18 | Wrapping films with mating cling strips |
Country Status (4)
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| US (1) | US6942909B2 (en) |
| EP (1) | EP1442874A3 (en) |
| CA (1) | CA2453748A1 (en) |
| MX (1) | MXPA04000997A (en) |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| US20050096613A1 (en) * | 2003-11-04 | 2005-05-05 | Carper James D. | Cling film fastening system for disposable soft goods |
| BRPI0416137A (en) * | 2003-11-04 | 2007-01-02 | Bostik Inc | cling film fastener system, packaging articles, envelope, tape, or soft disposable articles, laminar structure, article packaging container and laminar structure manufacturing method |
| US8053047B2 (en) | 2004-04-02 | 2011-11-08 | Curwood, Inc. | Packaging method that causes and maintains the preferred red color of fresh meat |
| US8545950B2 (en) | 2004-04-02 | 2013-10-01 | Curwood, Inc. | Method for distributing a myoglobin-containing food product |
| US8741402B2 (en) | 2004-04-02 | 2014-06-03 | Curwood, Inc. | Webs with synergists that promote or preserve the desirable color of meat |
| US8470417B2 (en) | 2004-04-02 | 2013-06-25 | Curwood, Inc. | Packaging inserts with myoglobin blooming agents, packages and methods for packaging |
| US8029893B2 (en) | 2004-04-02 | 2011-10-04 | Curwood, Inc. | Myoglobin blooming agent, films, packages and methods for packaging |
| US7867531B2 (en) | 2005-04-04 | 2011-01-11 | Curwood, Inc. | Myoglobin blooming agent containing shrink films, packages and methods for packaging |
| US8110259B2 (en) | 2004-04-02 | 2012-02-07 | Curwood, Inc. | Packaging articles, films and methods that promote or preserve the desirable color of meat |
| US7588820B2 (en) * | 2005-02-17 | 2009-09-15 | Cortec Corporation | Nano-particle corrosion inhibiting films |
| WO2006136002A1 (en) | 2005-04-14 | 2006-12-28 | Ibco Srl | Strip packaging material |
| CA2534943C (en) * | 2006-02-01 | 2012-01-31 | Thomas F. Clarke | Multi-layer wrap |
| EP1857270B1 (en) | 2006-05-17 | 2013-04-17 | Curwood, Inc. | Myoglobin blooming agent, films, packages and methods for packaging |
| US7611768B2 (en) | 2007-06-15 | 2009-11-03 | Berry Plastics Corporation | Slip-cling stretch film |
| US8197927B2 (en) * | 2007-06-15 | 2012-06-12 | Berry Plastics Corporation | Slip-cling stretch film |
| AU2013395445B2 (en) | 2013-07-26 | 2018-11-08 | Tama group | Wrapping web assembly and wrapping method |
| US10286625B2 (en) | 2013-08-20 | 2019-05-14 | Tama Plastic Industry | Wrapping material and method of manufacture for baling materials |
| US9765164B2 (en) | 2014-06-27 | 2017-09-19 | Dow Global Technologies Llc | Polyolefin compositions and uses thereof |
| CN107001740B (en) * | 2014-11-24 | 2018-03-20 | 博里利斯股份公司 | The product of polymer composition and Extrusion Coating |
| US10358245B2 (en) | 2015-09-25 | 2019-07-23 | Paul Kurt Riemenschneider, III | System and method of applying stretch film to a load |
| CA3135395C (en) * | 2020-10-23 | 2023-10-03 | Western Plastics, Inc. | Multi-layer packaging pad |
| IT202100032297A1 (en) * | 2021-12-22 | 2023-06-22 | Akro Brain Srl | REINFORCED STRETCH FILM, WITH HIGH CONTENT OF POST-CONSUMER RECYCLED RESINS |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4518654A (en) * | 1983-12-23 | 1985-05-21 | Mobil Oil Corporation | One-sided cling stretch wrap |
| US4820589A (en) * | 1986-11-17 | 1989-04-11 | Mobil Oil Corporation | Cling/no cling-slip stretch wrap film |
| US4833017A (en) * | 1987-04-17 | 1989-05-23 | Mobil Oil Corporation | Particle-impregnated one-sided cling stretch wrap film |
| CA1323973C (en) | 1987-04-17 | 1993-11-09 | Kathryn Ann Simmons | Stretch wrap film inherently exhibiting a significant cling property |
| EP0317166B2 (en) | 1987-11-19 | 1998-12-23 | Exxon Chemical Patents Inc. | Thermoplastic films for use in stretch/cling applications |
| US4996094A (en) * | 1988-09-26 | 1991-02-26 | Mobil Oil Corporation | One-sided cling/one-sided slip stretch wrap films |
| US5175049A (en) * | 1989-04-27 | 1992-12-29 | The Dow Chemical Company | Polyolefin laminate cling films |
| US5520896A (en) * | 1989-09-13 | 1996-05-28 | Elf Atochem North America, Inc. | Process to remove metal species from exhaust vapors |
| US5208096A (en) | 1990-01-08 | 1993-05-04 | Paragon Films Incorporated | Single-sided cling stretch film |
| DE69033235T2 (en) | 1990-05-18 | 1999-11-25 | Dow Chemical Co | ADHESIVE MULTILAYERED POLYOLEFINE FILM |
| GB9505524D0 (en) | 1995-03-18 | 1995-05-03 | Mobil Plastics Europ Inc | Product |
| US5998017A (en) | 1996-03-12 | 1999-12-07 | Tenneco Packaging | Stretch wrap films |
| US6132827A (en) * | 1997-05-19 | 2000-10-17 | Aep Industries, Inc. | Tacky stretch film and method of making and using the same |
| US5948493A (en) * | 1997-07-17 | 1999-09-07 | Reynolds Metals Company | Plastic wrap with cling layer |
| 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 |
| US6265055B1 (en) * | 1999-10-13 | 2001-07-24 | David Simpson | Multilayer stretch cling film |
| US6492010B1 (en) * | 1999-11-20 | 2002-12-10 | Intertape, Inc. | Premium stretch multilayer film products |
| DE60000694T2 (en) * | 2000-09-29 | 2003-06-12 | Duo Plast Ag | Self-adhesive multilayer stretch film, process for its production and use thereof for stretch wrapping packaging |
| US6984431B2 (en) * | 2002-12-23 | 2006-01-10 | Tama Plastic Industry | Method and material for multi-material wrapping of items and a method of making the same |
-
2003
- 2003-01-30 US US10/354,448 patent/US6942909B2/en not_active Expired - Fee Related
- 2003-12-10 EP EP03028271A patent/EP1442874A3/en not_active Withdrawn
- 2003-12-18 CA CA 2453748 patent/CA2453748A1/en not_active Abandoned
-
2004
- 2004-01-30 MX MXPA04000997A patent/MXPA04000997A/en active IP Right Grant
Also Published As
| Publication number | Publication date |
|---|---|
| EP1442874A2 (en) | 2004-08-04 |
| EP1442874A3 (en) | 2005-01-12 |
| US6942909B2 (en) | 2005-09-13 |
| MXPA04000997A (en) | 2004-08-05 |
| US20040151853A1 (en) | 2004-08-05 |
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