CA2557712A1 - Machine-direction oriented multilayer films - Google Patents

Machine-direction oriented multilayer films Download PDF

Info

Publication number
CA2557712A1
CA2557712A1 CA 2557712 CA2557712A CA2557712A1 CA 2557712 A1 CA2557712 A1 CA 2557712A1 CA 2557712 CA2557712 CA 2557712 CA 2557712 A CA2557712 A CA 2557712A CA 2557712 A1 CA2557712 A1 CA 2557712A1
Authority
CA
Canada
Prior art keywords
film
draw
range
down ratio
mdpe
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
Application number
CA 2557712
Other languages
French (fr)
Inventor
D. Ryan Breese
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Equistar Chemicals LP
Original Assignee
Individual
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Publication of CA2557712A1 publication Critical patent/CA2557712A1/en
Abandoned legal-status Critical Current

Links

Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C55/00Shaping by stretching, e.g. drawing through a die; Apparatus therefor
    • B29C55/02Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets
    • B29C55/023Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets using multilayered plates or sheets
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C55/00Shaping by stretching, e.g. drawing through a die; Apparatus therefor
    • B29C55/02Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C55/00Shaping by stretching, e.g. drawing through a die; Apparatus therefor
    • B29C55/02Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets
    • B29C55/04Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets uniaxial, e.g. oblique
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C55/00Shaping by stretching, e.g. drawing through a die; Apparatus therefor
    • B29C55/02Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets
    • B29C55/04Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets uniaxial, e.g. oblique
    • B29C55/06Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets uniaxial, e.g. oblique parallel with the direction of feed
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B32LAYERED PRODUCTS
    • B32BLAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00Layered products comprising a layer of synthetic resin
    • B32B27/32Layered products comprising a layer of synthetic resin comprising polyolefins
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29KINDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
    • B29K2023/00Use of polyalkenes or derivatives thereof as moulding material
    • B29K2023/04Polymers of ethylene
    • B29K2023/06PE, i.e. polyethylene
    • B29K2023/0608PE, i.e. polyethylene characterised by its density
    • B29K2023/0625LLDPE, i.e. linear low density polyethylene
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29KINDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
    • B29K2023/00Use of polyalkenes or derivatives thereof as moulding material
    • B29K2023/04Polymers of ethylene
    • B29K2023/06PE, i.e. polyethylene
    • B29K2023/0608PE, i.e. polyethylene characterised by its density
    • B29K2023/0641MDPE, i.e. medium density polyethylene
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29KINDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
    • B29K2023/00Use of polyalkenes or derivatives thereof as moulding material
    • B29K2023/04Polymers of ethylene
    • B29K2023/06PE, i.e. polyethylene
    • B29K2023/0608PE, i.e. polyethylene characterised by its density
    • B29K2023/065HDPE, i.e. high density polyethylene
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29KINDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
    • B29K2023/00Use of polyalkenes or derivatives thereof as moulding material
    • B29K2023/04Polymers of ethylene
    • B29K2023/08Copolymers of ethylene
    • B29K2023/083EVA, i.e. ethylene vinyl acetate copolymer
    • YGENERAL 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
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10TTECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T156/00Adhesive bonding and miscellaneous chemical manufacture
    • Y10T156/11Methods of delaminating, per se; i.e., separating at bonding face
    • YGENERAL 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
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10TTECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00Stock material or miscellaneous articles
    • Y10T428/31504Composite [nonstructural laminate]
    • Y10T428/31855Of addition polymer from unsaturated monomers

Abstract

A method for making films is disclosed. The method comprises orienting in the machine direction a multilayer film at a draw-down ratio effective to give the film a dart-drop strength that increases with increasing draw-down ratio. The multilayer film comprises at least one layer of a linear low density polyethylene and at least one layer of a high density polyethylene or a medium density polyethylene.

Description

MACHINE-DIRECTION ORIENTED MULTILAYER FILMS
FIELD OF THE INVENTION
s The invention relates to polyethylene films. More particularly, the invention relates to machine-direction oriented multilayer films.
BACKGROUND OF THE INVENTION
Polyethylene is divided into high-density (HDPE, density 0.941 g/cm3 or to greater), medium-density (MDPE, density from 0.926 to 0.940 g/cm3), low-density (LDPE, density from 0.910 to 0.925 g/cm3), and linear low-density polyethylene (LLDPE, density from 0.910 to 0.925 g/cm3). See ASTM D4976-98: Standard Specification for Polyethylene Plastic Molding and Extrusion Materials.
Polyethylene can also be divided by molecular weight. For instance, ultra-high is molecular weight polyethylene denotes those which have a weight average molecular weight (Mw) greater than 3,000,000. See U.S. Pat. No. 6,265,504.
High molecular weight polyethylene usually denotes those which have an Mw from 130,000 to 1,000,000.
One of the main uses of polyethylene (HDPE, MDPE, LLDPE, and LDPE) is 2o in film applications, such as grocery sacks, institutional and consumer can liners, merchandise bags, shipping sacks, food packaging films, multi-wall bag liners, produce bags, deli wraps, stretch wraps, and shrink wraps. The key physical properties of polyethylene film include tear strength, impact strength, tensile strength, stiffness and transparency. Film stiffness can be measured by modulus.
2s Modulus is the resistance of the film to deformation under stress.
Machine direction orientation (MDO) is known to the polyolefin industry.
When a polymer is strained under uniaxial stress, the orientation becomes aligned in the direction of pull. For instance, U.S. Pat. No. 6,391,411 teaches the MDO
of high molecular weight (both Mn and Mw greater than 1,000,000) HDPE films. However, MDO of high molecular weight HDPE films are limited because these films are difficult to stretch to a high draw-down ratio.
The current polyethylene films typically compromise several properties, such as modulus, yield strength, and break strength, to meet the package requirements s for dart drop impact strength. Polymer films that do not compromise such properties are desirable for improving the performance of the bags, as well as the economics associated with producing and filling the bags. For example, by increasing the modulus and the yield strength of the film, larger bags can be produced, which would allow packaging larger quantities of goods while retaining io their shape after being handled by the consumer. Bags with higher modulus would also allow the filling lines to run faster, improving the overall economics of the filling process.
By increasing the yield strength of the film, the bags would be less likely to elongate under stress and therefore they retain the original shape and dimensions.
is This would reduce the amount of breaks which are resulted from the film yielding and thinning under load. Also, the printed surface of the bag would not be distorted, maintaining the aesthetic quality of the package and enhancing brand recognition by the consumer.
In addition, the films that do not compromise the aforementioned properties 2o could allow the reduction in the film thickness, further improving the economics associated with the products. Such innovations are desirable to all in the heavy duty shipping sack industry for creating new products that provide both performance and economic benefit.
SUMMARY OF THE INVENTION
2s The method of the invention comprises orienting a multilayer film in the machine-direction (MD) at a draw-down ratio effective to give the film a dart-drop strength that increases with increasing draw-down ratio. The multilayer film comprises at least one layer of a linear low density polyethylene (LLDPE) and at least one layer of a high density polyethylene (HDPE) or a medium density 3o polyethylene (MDPE).
When a film is stretched, its dart-drop impact strength usually is reduced as the film becomes thinner. I surprisingly found that when a multilayer film is oriented in the machine direction beyond a certain draw-down ratio, the dart-drop strength of the film increases with increasing draw-down ratio and the oriented film can s eventually have a dart-drop value greater than that of the original film.
Thus, the invention provides a new method for producing a machine-direction oriented (MDO) multilayer film which has a combination of high modulus, high tensile, and high dart-drop impact strength.
to DETAILED DESCRIPTION OF THE INVENTION
The method of the invention comprises orienting a multilayer film in the machine-direction (MD) at a draw-down ratio effective to give the film a dart-drop strength that increases with increasing draw-down ratio. The multilayer film comprises at least one layer of a linear low density polyethylene (LLDPE) and at is least one layer of a high density polyethylene (HDPE) or a medium density polyethylene (MDPE).
Suitable LLDPE preferably is copolymers of ethylene with 5 wt % to 15 wt of a long chain a-olefin such as 1-butene, 1-hexene, and 1-octene. Suitable LLDPE
includes those which have a density within the range of about 0.910 g/cm3 to about 20 0.925 g/crn3. Suitable LLDPE also includes the so called very low density polyethylene (VLDPE). Suitable VLDPE has a density within the range of 0.865 g/cm3 to 0.910 g/cm3.
Suitable MDPE preferably has a density within the range of about 0.926 g/cm3 to about 0.940 g/cm3. More preferably, the density is within the range of about 2s 0.930 g/cm3 to about 0.940 g/cm3. Preferred MDPE is a copolymer that comprises from about 85 wt % to about 98 wt % of recurring units of ethylene and from about 2 wt % to about 15 wt % of recurring units of a C3 to Coo a-olefin. Suitable C3 to Coo a-olefins include propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, and 1-octene, and the like, and mixtures thereof.
so Preferably, the MDPE has a bimodal or multimodal molecular weight distribution. Method for making bimodal or multimodal MDPE is known. For instance, U.S. Pat. No. 6,486,270 teaches the preparation of MDPE by a multiple-zone process.
Suitable HDPE preferably has a density within the range of about 0.941 g/cm3 to about 0.970 g/cm3. More preferably, the density is within the range of about s 0.945 g/cm3 to about 0.965 g/cm3. Most preferably, the density is within the range of 0.958 g/cm3 to 0.962 g/cm3.
Preferably, the LLDPE, MDPE and HDPE have an M12 from about 0.01 to about 1.5 dg/min, and more preferably from about 0.01 to about 1.0 dg/min.
Preferably, the LLDPE, MDPE and HDPE have an MFR from about 50 to about 300.
io Melt index (M12) is usually used to measure polymer molecular weight, and melt flow ratio (MFR) is used to measure the molecular weight distribution. A larger M12 indicates a lower molecular weight. A larger MFR indicates a broader molecular weight distribution. MFR is the ratio of the high-load melt index (HLMI) to M12. The M12 and HLMI can be measured according to ASTM D-1238. The MI~ is measured is at 190°C under 2.16 kg pressure. The HLMI is measured at 190°C under 21.6 kg pressure.
Preferably, the LLDPE, MDPE, and HDPE have a number average molecular weight (Mn) within the range of about 10,000 to about 500,000, more preferably from about 11,000 to about 50,000, and most preferably from about 11,000 to about 20 35,000. Preferably, the LLDPE, MDPE, and HDPE have a weight average molecular weight (Mw) within the range of about 120,000 to about 1,000,000, more preferably from about 135,000 to about 500,000, and most preferably from about 140,000 to about 250,000. Preferably, the LLDPE, MDPE, and HDPE have a molecular weight distribution (Mw/Mn) within the range of about 3 to about 20, more 2s preferably from about 4 to about 18, and most preferably from about 5 to about 17.
The Mw, Mn, and Mw/Mn are obtained by gel permeation chromatography (GPC) on a Waters GPC2000CV high temperature instrument equipped with a mixed bed GPC column (Polymer Labs mixed B-LS) and 1,2,4-trichlorobenzene (TCB) as the mobile phase. The mobile phase is used at a nominal flow rate of 1.0 so mL/min and a temperature of 145°C. No antioxidant is added to the mobile phase, but 800ppm BHT is added to the solvent used for sample dissolution. Polymer samples are heated at 175°C for two hours with gentle agitation every 30 minutes.
Injection volume is 100 microliters.
The Mw and Mn are calculated using the cumulative matching % calibration procedure employed by the Waters Millennium 4.0 software. This involves first s generating a calibration curve using narrow polystyrene standards (PSS, products of Waters Corporation), then developing a polyethylene calibration by the Universal Calibration procedure.
Suitable LLDPE, MDPE, and HDPE can be produced by Ziegler, single-site, or any other olefin polymerization catalysts. Ziegler catalysts are well known.
io Examples of suitable Ziegler catalysts include titanium halides, titanium alkoxides, vanadium halides, and mixtures thereof. Ziegler catalysts are used with cocatalysts such as alkyl aluminum compounds.
Single-site catalysts can be divided into metallocene and non-metallocene.
Metallocene single-site catalysts are transition metal compounds that contain is cyclopentadienyl (Cp) or Cp derivative ligands. For example, U.S. Pat. No.
4,542,199 teaches metallocene catalysts. Non-metallocene single-site catalysts contain ligands other than Cp but have the same catalytic characteristics as metallocenes. The non-metallocene single-site catalysts may contain heteroatomic ligands, e.g., boraaryl, pyrrolyl, azaborolinyl or quinolinyl. For example, U.S. Pat.
2o Nos. 6,034,027, 5,539,124, 5,756,611, and 5,637,660 teach non-metallocene catalysts.
Optionally, the multilayer film comprises other layers such as gas-barrier, adhesive, medical, flame retardant layers, and the like. Suitable materials for the optional layers include poly(vinylidene chloride), polyvinyl alcohol), polyamide zs (Nylon), polyacrylonitrile, ethylene-vinyl acetate copolymers (EVA), ethylene-methyl acrylate copolymers (EMA), ethylene-acrylic acid copolymers (EAA), ionomers, malefic anhydride grafted polyolefins, IC-resins (styrene/butadiene block copolymers), and polyethylene terephthalate) (PET), the like, and mixtures thereof.
The multilayer films can be made by co-extrusion, coating, and any other 30 laminating processes. They can be made by casting or blown film processes.
Blown film process includes high-stalk and in-pocket processes. The difference s between the high-stalk process and the in-pocket process is that in the high-stalk process, the extruded tube is inflated a distance (i.e., the length of the stalk) from the extrusion die, while the extruded tube in the in-pocket process is inflated as the tube exits the extrusion die.
s The multilayer film is uniaxially stretched in the machine (or processing) direction. This is so called MDO. During the MDO, the film from the blown-film line or other film process is heated to an orientation temperature. Preferably, the orientation temperature is between 60% of the difference between the glass transition temperature (Tg) and the melting point (Tm) and the melting temperature to (Tm). For instance, if the blend has a Tg of 25°C and a Tm of 125°C, the orientation temperature is preferably within the range of about 60°C to about 125°C.
The heating is preferably performed utilizing multiple heating rollers.
Next, the heated film is fed into a slow draw roll with a nip roller, which has the same rolling speed as the heating rollers. The film then enters a fast draw roll.
is The fast draw roll has a speed that is 2 to 10 times faster than the slow draw roll, which effectively stretches the film on a continuous basis.
The stretched film then enters annealing thermal rollers, which allow stress relaxation by holding the film at an elevated temperature for a period of time. The annealing temperature is preferably within the range of about 100°C to about 125°C
2o and the annealing time is within the range of about 1 to about 2 seconds.
Finally, the film is cooled through cooling rollers to an ambient temperature.
The ratio of the film thickness before and after orientation is called "draw-down ratio." For example, when a 6-mil film is stretched to O.G-mil, the draw-down ratio is 10:1. According to the method of the invention, the draw-down ratio is 2s sufficiently high at which the dart-drop strength of the film increases with the draw-down ratio. As expected, when the multilayer film is MD-oriented, its dart-drop value decreases with increasing draw-down ratio. However, I surprisingly found that when the film is oriented beyond a certain point, the dart-drop value increases with draw-down ratio. As the orientation continues, the oriented film can have an ultimate dart-3o drop value greater than that of the un-oriented film.
The critical point beyond which the dart-drop value increases with draw-down ratio depends on many factors, including the properties of the layers, the film process conditions and the MDO conditions. Preferably, the draw-down ratio is greater than 6:1. More preferably, the draw-down ratio is greater than 8:1.
Most s preferably, the draw-down ratio is greater than 10:1. Preferably, the multilayer film is oriented to an extent that the layers of the film start delaminating and forming a multi-wall film.
The invention includes the MD oriented film made by the method of the invention. The invention also includes the multi-wall film made by the method of the to invention. The film of the invention not only has a high modulus and high tensile strength but also has high dart-drop impact strength. The film of the invention is particularly useful for making heavy-duty bags due to its combination of high modulus, high tensile and high impact strength.
Preferably, the film of the invention has a 1 % secant MD and TD (transverse is direction) modulus greater than 150,000 psi, more preferably greater than 200,000 psi, and most preferably greater than 250,000 psi. Modulus is tested according to ASTM E-111-97.
Preferably, the film has an MD tensile strength at yield and at break greater than 30,000 psi, more preferably greater than 35,000 psi, and most preferably 2o greater than 40,000 psi. Tensile strength is tested according to ASTM D-882.
Preferably, the film has a haze less than 30%, and more preferably less than 50%. The haze is tested according to ASTM D1003-92: Standard Test Method for Haze and Luminous Transmittance of Transparent Plastics, Oct. 1992.
Preferably, the film has a gloss greater than 20, and more preferably greater than 30. The gloss 2s is tested according to ASTM D2457-90: Standard Test Method for Specular Gloss of Plastic Films and Solid Plastics.
The following examples merely illustrate the invention. Those skilled in the art will recognize many variations that are within the spirit of the invention and scope of the claims.
MACHINE DIRECTION ORIENTATION OF LLDPE/MDPE/LLDPE
THREE-LAYER FILMS
A medium density polyethylene (XL3805, product of Equistar Chemicals, LP, s M12: 0.057 dg/min, density: 0.938 g/cm3, Mn: 18,000, Mw: 209,000) is coextruded with a linear low density polyethylene (GS707, product of Equistar Chemicals, LP, density: 0.915 g/cm3, M12: 0.700 dg/min, Mn: 30,000, Mw: 120,000) and converted into an equally layered three layer (LLDPE/MDPE/LLDPE) film with a thickness of 14.0 mil on 1000 mm die with 2.5 mm die gap. The films are produced in the pocket to and at blow-up ratios (BUR) of 2:1.
The films are then stretched into thinner films in the machine direction with draw-down ratios 4, 5, 6, 7, 8 and 9.3:1 in Examples 1-6, respectively. The draw-down ratio of 9.3:1 is the maximum draw-down ratio limited by the orientation is equipment and not the polymer film. The film properties are listed in Table 1. It is shown that at lower draw ratios, the dart drop values decrease with increasing draw-down ratios as expected. After a particular draw ratio, the dart drop values begin to increase and significantly exceed that dart drop value of the initial film.
Properties vs. Draw-down Ratio of Multilayer Films Ex. Draw-Dart MD TD MD TensileMD TensileGlossHaze No. DownDrop ModulusModulusStrength Strength RatioF50 kpsi kpsi @ Yield @ Break Grams Kpsi kpsi 1 4:1 136 122 149 8.85 13.8 22 39 2 5:1 128 144 155 16.5 20.2 26 34 3 6:1 134 170 160 24.3 26.7 29 31 4 7:1 155 200 164 32.0 33.0 31 30 8:1 190 236 167 39.5 39.5 32 30 6 9.3:1258 293 171 47.9 47.9 31 33 s Machine Direction Orientation of HDPE Monolayer Films Examples 1-6 are repeated, but the films are made as a monolayer HDPE
structure (L5005, product of Equistar Chemicals, LP, density: 0.949 g/cm3, M12:
0.057 dg/min, Mn: 12,600, Mw: 212,000). The film properties are listed in Table 2, which shows that the dart drop values significantly decrease with increasing draw-io down ratio and the drastic upturn in dart drop values seen with the multilayer films in Examples 1-6 is not observed. The draw-down ratio of 7.9:1 is the maximum draw-down ratio limited by the orientation equipment and not by the polymer film.
Properties vs. Draw-down Ratio of Monolayer Films Ex.Draw-Dart MD TD MD TensileMD TensileGlossHaze No.Down Drop ModulusModuluStrength Strength RatioF50 k si s @ Yield @ Break ' k K si k si Grams si C7 4:1 137 218 234 6.53 15.3 12 60 C8 5:1 105 239 236 7.17 20.1 14 56 C9 6:1 86 261 238 7.81 25.0 16 52 C107:1 81 286 240 8.45 29.8 19 48 C117.9:188 310 241 9.02 34.1 23 44 s COMPARATIVE EXAMPLES 12-19 Machine Direction Orientation of Monolayer Films From MDPE - LLDPE Blend Examples 1-6 are repeated, but the films that are made as monolayer from the blend of MDPE (XL3805, product of Equistar Chemicals, LP, M12: 0.057 dg/min, to density: 0.938 g/cm3, Mn: 18,000, Mw: 209,000) and LLDPE (GS707, product of Equistar Chemicals, LP, density: 0.915 g/cm3, M12: 0.700 dg/min, Mn: 30,000, Mw:
120,000). The components in the blend have ratios so that the percentage of each material present in the overall film is the same as that of the multilayer films represented in Examples 1-6. The film properties are listed in Table 3, which shows is that the dart drop values significantly decrease with increasing draw-down ratio and the drastic upturn seen with the multilayer films in Examples 1-6 is not observed.
The draw-down ratio of 10.6:1 is the maximum draw-down ratio limited by the orientation equipment and not by the polymer film.
Properties vs. Draw-down Ratio of Monolayer MDPE-LLDPE Blend Films Ex. Draw-Dart MD TD MD TensileMD TensileGlossHaze No. Down Drop ModulusModuluStrength Strength RatioF50 kpsi s kpsi@ Yield @ Break Grams Kpsi kpsi C12 4:1 140 104 129 7.32 13.4 27 32 C13 5:1 120 120 135 12.2 17.5 30 29 C14 6:1 105 139 140 17.1 21.6 34 27 C15 7:1 93 161 145 22.1 25.7 36 25 C16 8:1 87 186 148 27.0 29.9 38 24 C 9:1 84 215 151 32.0 34. 0 39 24 C18 10:1 86 249 154 36.9 38.1 39 25 C19 10.6:189 272 156 39.9 40.5 9 26

Claims (14)

1. A method comprising orienting a multilayer film in the machine direction at a draw-down ratio effective to give the film a dart-drop strength that increases with increasing draw-down ratio, wherein the film comprises at least one layer of a linear low density polyethylene (LLDPE) and at least one layer of a high density polyethylene (HDPE) or a medium density polyethylene (MDPE).
2. The method of claim 1 wherein the HDPE has a density within the range of 0.941 g/cm3 to 0.970 g/cm3.
3. The method of claim 1 wherein the MDPE has a density within the range of 0.926 g/cm3 to 0.940 g/cm3.
4. The method of claim 1 wherein the LLDPE has a density within the range of 0.865 to 0.925 g/cm3.
5. The method of claim 1 wherein the film is oriented at a draw-down ratio effective to cause the film delaminating.
6. The method of claim 1 wherein the film is oriented at a draw-down ratio to give the film a dart-drop strength greater than that of the original film.
7. The method of claim 1 wherein the LLDPE, HDPE, and MDPE each has a weight average molecular weight (Mw) within the range of 120,000 to 1,000,000.
8. The method of claim 7 wherein the Mw is within the range of 135,000 to 500,000.
9. The method of claim 7 wherein the Mw is within the range of 140,000 to 250, 000.
10. The method of claim 1 wherein the LLDPE, HDPE, and MDPE each has a number average molecular weight (Mn) within the range of 10,000 to 500,000.
11. The method of claim 10 wherein the Mn is within the range of 11,000 to 50,000.
12 12. The method of claim 10 wherein the Mn is within the range 11,000 to 35,000.
13. An oriented film made by the method of claim 1.
14. A multi-wall film made by the method of claim 5.
CA 2557712 2004-03-10 2005-02-15 Machine-direction oriented multilayer films Abandoned CA2557712A1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
US10/797,640 US20050200046A1 (en) 2004-03-10 2004-03-10 Machine-direction oriented multilayer films
US10/797,640 2004-03-10
PCT/US2005/004719 WO2005092595A1 (en) 2004-03-10 2005-02-15 Machine-direction oriented multilayer films

Publications (1)

Publication Number Publication Date
CA2557712A1 true CA2557712A1 (en) 2005-10-06

Family

ID=34920094

Family Applications (1)

Application Number Title Priority Date Filing Date
CA 2557712 Abandoned CA2557712A1 (en) 2004-03-10 2005-02-15 Machine-direction oriented multilayer films

Country Status (7)

Country Link
US (1) US20050200046A1 (en)
EP (1) EP1740363A1 (en)
JP (1) JP2007528309A (en)
KR (1) KR20060129049A (en)
CN (1) CN1929985A (en)
CA (1) CA2557712A1 (en)
WO (1) WO2005092595A1 (en)

Families Citing this family (30)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20060177641A1 (en) * 2005-02-09 2006-08-10 Breese D R Multilayer polyethylene thin films
US8034461B2 (en) * 2005-02-09 2011-10-11 Equistar Chemicals, Lp Preparation of multilayer polyethylene thin films
EP1923200A1 (en) * 2006-11-20 2008-05-21 Borealis Technology Oy Article
CA2663929A1 (en) * 2006-11-21 2008-05-29 Fina Technology, Inc. Polyethylene useful for producing film and molded articles in a process which uses solid state stretching
EP1941998B2 (en) 2006-12-21 2016-03-16 Borealis Technology Oy Film
DE602006013673D1 (en) 2006-12-21 2010-05-27 Borealis Tech Oy Film
US7794848B2 (en) * 2007-01-25 2010-09-14 Equistar Chemicals, Lp MDO multilayer polyethylene film
ES2354383T5 (en) * 2007-08-10 2021-06-21 Borealis Tech Oy Article comprising a polypropylene composition
EP2067799A1 (en) * 2007-12-05 2009-06-10 Borealis Technology OY Polymer
EP2354184B1 (en) 2010-01-29 2012-08-22 Borealis AG Polyethylene moulding composition with improved stress crack/stiffness relationship and impact resistance
EP2354183B1 (en) 2010-01-29 2012-08-22 Borealis AG Moulding composition
EP2653391B1 (en) 2012-04-18 2015-07-29 Borealis AG A process for collation shrink wrapping a plurality of individual containers
ES2555271T3 (en) * 2012-04-18 2015-12-30 Borealis Ag Shrink wrapping films
EP2698251B1 (en) * 2012-08-13 2017-03-01 Borealis AG Films
US9670347B2 (en) 2013-08-14 2017-06-06 Borealis Ag Propylene composition with improved impact resistance at low temperature
JP2016528368A (en) 2013-08-21 2016-09-15 ボレアリス・アクチェンゲゼルシャフトBorealis Ag High flow polyolefin composition having high rigidity and toughness
CN105452365B (en) 2013-08-21 2018-04-17 博里利斯股份公司 High flowing polyolefin composition with high rigidity and toughness
EP2860031B1 (en) * 2013-10-11 2016-03-30 Borealis AG Machine direction oriented film for labels
EP3060589B9 (en) 2013-10-24 2018-04-18 Borealis AG Low melting pp homopolymer with high content of regioerrors and high molecular weight
EP3071606B1 (en) 2013-11-22 2017-08-16 Borealis AG Low emission propylene homopolymer with high melt flow
ES2929491T3 (en) 2013-12-04 2022-11-29 Borealis Ag Phthalate-free PP homopolymers for meltblown fibers
CN105980457B (en) 2013-12-18 2019-03-22 博里利斯股份公司 With improved rigidity/tough sexual balance BOPP film
WO2015107020A1 (en) 2014-01-17 2015-07-23 Borealis Ag Process for preparing propylene/1-butene copolymers
CN105934476B (en) 2014-02-06 2019-03-29 北欧化工公司 Soft transparent impact copolymer
CN112225997B (en) 2014-02-06 2023-09-22 北欧化工公司 High impact strength flexible copolymers
EP2907841A1 (en) 2014-02-14 2015-08-19 Borealis AG Polypropylene composite
EP2947118B1 (en) 2014-05-20 2017-11-29 Borealis AG Polypropylene composition for automotive interior applications
WO2017207221A1 (en) 2016-06-03 2017-12-07 Borealis Ag Multilayer structure
AR113268A1 (en) 2017-10-10 2020-03-11 Dow Global Technologies Llc UNIAXIAL ORIENTED POLYMERIC FILMS AND ARTICLES MANUFACTURED FROM THEM
EP4239015A1 (en) 2022-03-02 2023-09-06 Borealis AG Monoaxially oriented film comprising a polyethylene composition

Family Cites Families (32)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3127133A1 (en) * 1981-07-09 1983-01-27 Hoechst Ag, 6000 Frankfurt METHOD FOR PRODUCING POLYOLEFINS AND THEIR COPOLYMERISATS
US4501798A (en) * 1983-05-05 1985-02-26 American Can Company Unbalanced oriented multiple layer film
US4606879A (en) * 1985-02-28 1986-08-19 Cerisano Frank D High stalk blown film extrusion apparatus and method
JPH0655433B2 (en) * 1985-08-12 1994-07-27 三井石油化学工業株式会社 Inflation film, its manufacturing method and equipment
DE3689520T2 (en) * 1985-11-07 1994-04-28 Showa Denko Kk TRANSPARENT, HIGH DENSITY POLYETHYLENE FILM AND THEIR PRODUCTION.
JPH07100348B2 (en) * 1987-07-13 1995-11-01 三菱化学株式会社 Film production method
US5024799A (en) * 1987-09-14 1991-06-18 Tredegar Industries, Inc. Method for producing an embossed oriented film
JP2615931B2 (en) * 1988-10-27 1997-06-04 三菱化学株式会社 Film production method
JP2785403B2 (en) * 1989-12-19 1998-08-13 三菱化学株式会社 Film production method
US5348794A (en) * 1990-01-30 1994-09-20 Nippon Petrochemicals Company, Limited Monoaxially oriented multilayered packaging material
JP3195403B2 (en) * 1992-03-13 2001-08-06 旭化成株式会社 Heat shrinkable multilayer film
EP0731750A4 (en) * 1993-12-01 1998-04-29 Mobil Oil Corp Oriented hdpe films with skin layers
JP3431706B2 (en) * 1994-12-16 2003-07-28 新日本石油化学株式会社 Laminate, nonwoven fabric or woven fabric and reinforced laminate using them
US5539124A (en) * 1994-12-19 1996-07-23 Occidental Chemical Corporation Polymerization catalysts based on transition metal complexes with ligands containing pyrrolyl ring
US6419966B1 (en) * 1994-12-22 2002-07-16 Exxonmobil Chemical Patents Inc. Polyethylene articles with improved resistance to water vapor transmission
US5637660A (en) * 1995-04-17 1997-06-10 Lyondell Petrochemical Company Polymerization of α-olefins with transition metal catalysts based on bidentate ligands containing pyridine or quinoline moiety
JP3493079B2 (en) * 1995-06-19 2004-02-03 東燃化学株式会社 Method for producing microporous thermoplastic resin membrane
US6034027A (en) * 1996-05-17 2000-03-07 Equistar Chemicals, Lp Borabenzene based olefin polymerization catalysts containing a group 3-10 metal
US5962598A (en) * 1996-07-26 1999-10-05 Equistar Chemicals, Lp Polyethlene film composition having broad molecular weight distribution and improved bubble stability
US5989725A (en) * 1997-01-16 1999-11-23 Tenneco Packaging Clear high molecular weight film
US5756611A (en) * 1997-02-21 1998-05-26 Lyondell Petrochemical Company α-olefin polymerization catalysts
US6013378A (en) * 1997-03-17 2000-01-11 Tenneco Packaging HMW HDPE film with improved impact strength
JPH1158635A (en) * 1997-08-08 1999-03-02 Mitsui Chem Inc Inflation multilayered film
US6391411B1 (en) * 1999-06-03 2002-05-21 Printpack Illinois, Inc. Machine direction oriented high molecular weight, high density polyethylene films with enhanced water vapor transmission properties
US6265504B1 (en) * 1999-09-22 2001-07-24 Equistar Chemicals, Lp Preparation of ultra-high-molecular-weight polyethylene
JP2003527474A (en) * 2000-03-16 2003-09-16 バーゼル、ポリオレフィン、ゲゼルシャフト、ミット、ベシュレンクテル、ハフツング Method for producing polyethylene
US6486270B1 (en) * 2000-08-25 2002-11-26 Equistar Chemicals, Lp High molecular weight, medium density polyethylene
US7135526B2 (en) * 2001-06-22 2006-11-14 Univation Technologies, Llc Very low density polyethylene and high density polyethylene blends
DE60222902T2 (en) * 2001-07-19 2008-07-17 Lankhorst Pure Composites B.V. POLYOLEFIN FILM, STRIP OR YARN
US6635701B2 (en) * 2001-08-09 2003-10-21 Equistar Chemicals L.P. Oriented high density polyethylene film, compositions and process suitable for preparation thereof
US6613841B2 (en) * 2002-01-28 2003-09-02 Equistar Chemicals, Lp Preparation of machine direction oriented polyethylene films
US6878454B1 (en) * 2003-12-05 2005-04-12 Univation Technologies, Llc Polyethylene films

Also Published As

Publication number Publication date
JP2007528309A (en) 2007-10-11
EP1740363A1 (en) 2007-01-10
KR20060129049A (en) 2006-12-14
US20050200046A1 (en) 2005-09-15
CN1929985A (en) 2007-03-14
WO2005092595A1 (en) 2005-10-06

Similar Documents

Publication Publication Date Title
CA2597313C (en) Multilayer polyethylene thin films
CA2557712A1 (en) Machine-direction oriented multilayer films
US8034461B2 (en) Preparation of multilayer polyethylene thin films
EP3261838B1 (en) Laminated film structure based on polyethylene only
US7078081B2 (en) Preparation of polyethylene films
WO2015052246A1 (en) Machine direction oriented film for labels
CA2569477A1 (en) Polyethylene films having high resistance to deformation or elongation
CA2553553A1 (en) Preparation of polyethylene films
MXPA06010220A (en) Machine-direction oriented multilayer films
MXPA06008535A (en) Preparation of polyethylene films

Legal Events

Date Code Title Description
FZDE Discontinued
FZDE Discontinued

Effective date: 20110215