WO2000004090A1 - Procede de reduction du dechirement de films souffles et a base de polyolefine - Google Patents

Procede de reduction du dechirement de films souffles et a base de polyolefine Download PDF

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Publication number
WO2000004090A1
WO2000004090A1 PCT/US1999/015758 US9915758W WO0004090A1 WO 2000004090 A1 WO2000004090 A1 WO 2000004090A1 US 9915758 W US9915758 W US 9915758W WO 0004090 A1 WO0004090 A1 WO 0004090A1
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WO
WIPO (PCT)
Prior art keywords
nucleating agent
polyethylene
melt
sorbitol
dibenzylidene sorbitol
Prior art date
Application number
PCT/US1999/015758
Other languages
English (en)
Inventor
Arnold Lustiger
Original Assignee
Exxon Research And Engineering Company
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 Exxon Research And Engineering Company filed Critical Exxon Research And Engineering Company
Priority to AU49885/99A priority Critical patent/AU4988599A/en
Publication of WO2000004090A1 publication Critical patent/WO2000004090A1/fr

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L51/00—Compositions of graft polymers in which the grafted component is obtained by reactions only involving carbon-to-carbon unsaturated bonds; Compositions of derivatives of such polymers
    • C08L51/06—Compositions of graft polymers in which the grafted component is obtained by reactions only involving carbon-to-carbon unsaturated bonds; Compositions of derivatives of such polymers grafted on to homopolymers or copolymers of aliphatic hydrocarbons containing only one carbon-to-carbon double bond
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F255/00—Macromolecular compounds obtained by polymerising monomers on to polymers of hydrocarbons as defined in group C08F10/00
    • C08F255/02—Macromolecular compounds obtained by polymerising monomers on to polymers of hydrocarbons as defined in group C08F10/00 on to polymers of olefins having two or three carbon atoms
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K5/00—Use of organic ingredients
    • C08K5/04—Oxygen-containing compounds
    • C08K5/15—Heterocyclic compounds having oxygen in the ring
    • C08K5/156—Heterocyclic compounds having oxygen in the ring having two oxygen atoms in the ring
    • C08K5/1575—Six-membered rings
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
    • C08L23/02—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers not modified by chemical after-treatment
    • C08L23/04—Homopolymers or copolymers of ethene
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L2314/00—Polymer mixtures characterised by way of preparation
    • C08L2314/06—Metallocene or single site catalysts

Definitions

  • the invention is directed towards increasing tear strength in metallocene-prepared polyethylene.
  • Metallocene-prepared polyolefin films are frequently formed as blown films.
  • Film blowing involves continuously extruding a polymer melt through a die in order to form a continuous cylinder of viscous polymer, and then expanding the diameter of the cylinder through, for example, a pressure differential between the inside and outside of the cylinders.
  • the cylinder is at a desired radius which is approximately equal to ⁇ times the reciprocal of the width of a take-up spool, and when the cylinder's wall thickness is approximately equal to the desired film thickness, the film is parted longitudinally and then wound onto the take-up spool.
  • Metallocene-prepared polyolefin films generally provide significant improvements in physical properties over their Ziegler-Natta-prepared counterparts.
  • one property in which further improvement is thought to be possible is “tear strength”.
  • Film tearing can occur longitudinally along the film (also known as the "machine direction” or “MD”) or transversely across the film (known as the "transverse direction” or “TD”). Tear strength can be increased by increasing the blown-film thickness; however, this approach is costly and can result in less productive processing conditions. There is therefore a need for a method for reducing tearing and increasing tear strength in blown polyolefin films.
  • the invention is a method for reducing tear strength in a blown film formed from a metallocene-prepared polyethylene melt.
  • the method comprising adding to the melt an effective amount of a nucleating agent selected from the group consisting of dibenzylidene sorbitol, paramethyl dibenzylidene sorbitol, dimethyl dibenzylidene sorbitol, ethylene copolymers containing grafted maleic anhydride, ethylene copolymers containing grafted acrylic acid, and mixtures thereof.
  • the invention is a composition
  • a metallocene-prepared polyethylene melt and a nucleating agent selected from the group consisting of dibenzylidene sorbitol paramethyl dibenzylidene sorbitol, dimethyl dibenzylidene sorbitol, ethylene copolymers containing grafted maleic anhydride, ethylene copolymers containing grafted acrylic acid, and mixtures thereof.
  • Film tearing can be reduced in a process for forming a blown metallocene-prepared polyolefin film from a melt by adding a nucleating agent to the melt.
  • the preferred nucleating agents are sorbitol-based materials, phmalocyamine-based pigments, acrylic acid or maleic anhydride ethylene copolymers.
  • the sorbitols are selected from dibenzylidene sorbitol, paramethyl dibenzylidene sorbitol, or dimethyl dibenzylidene sorbitol. Paramethyl dibenzylidene sorbitol is particularly preferred.
  • Mixtures of the aforementioned nucleating agents may also be used.
  • the additive may also be used together with sodium stearate as an acid-neutralizing agent present in a concentration ranging from about 100 to about 1,000 parts per million.
  • Polyethylene useful in the practice of the invention ranges in melt index from about 0.5 dg/min to about 3.0 dg/min with about 0.5 dg/min to about 1.5 dg/min being preferred. Density ranges from 0.915 g/cm 3 to about 0.925 g/cm 3 , with about 0.917 g/cm 3 to about 0.920 g/cm 3 being preferred. Melts formed from the polyethylene and the nucleating agents of the invention are compatible with conventional film-blowing equipment. Methods of combining the polyethylene and nucleating agent include melt-homogenization and tumbling powdered polyethylene resin and powdered nucleating agent together in a barrel blender.
  • the graft copolymers used in this invention range in density from about 0.92 g/cm 3 to about 0.96 g/cm 3 , with .95 g/cm 3 being preferred in the case of ethylene-acrylic acid and .92 g/cm preferred in the case of maleic anhydride.
  • the copolymer may also contain about 1 to about 25 butene branches per thousand carbon atoms, with about 10 to about 18 branches being preferred.
  • the acrylic acid level in the ethylene acrylic acid graft copolymers is about 2 to about 8% with about 5 to about 6% being preferred.
  • the maleic anhydride level in the ethylene maleic anhydride graft copolymer is about 0.25 to about 2%, with 1% being preferred.
  • Copolymer nucleating agents useful in the invention range in melt index from about 0.5 dg/min to about 10 dg/min with about 1 dg/min to about 6 dg/min being preferred.
  • the nucleating agents of the present invention provide enhanced properties in blown polyethylene films. An effective amount of the nucleating agent, or mixtures thereof, is added to a polyethylene melt prior to film processing.
  • the effective amount generally ranges from about 0.1 wt.% to about 5 wt.% based on the added weight of the polyethylene and nucleating agent, with the range of about 0.1 wt.% to about 0.5 wt.% being preferred for the sorbitol based nucleating agents, about 2.5 to about 5.0 wt.% is preferred for the graft copolymer nucleating agents.
  • Table 1 summarizes the physical properties of seven representative metallocene-prepared polyethylene melts that contain nucleating agents of the present invention. Such melts are compatible with conventional film-blowing equipment.
  • the formulations may be melt homogenized or, alternatively, powdered polyethylene resin and powdered nucleating agents may be tumbled together in a barrel blender.
  • Table 2 summarizes physical properties of film blown from the melts of Table 1.
  • Sample 1 is formed from base resin without additives.
  • Samples 2 through 6 all show improvement in machine direction and/or transverse direction tear strength both initially and 30 days after film formation. The improvement is obtained without a reduction in stiffness, and in two cases the modulus actually increases in the presence of the nucleating agent.
  • Transverse direction tear strength showed an improvement over the control samples after 30 days in all cases and an initial improvement in all cases except Sample 4.
  • a metallocene-prepared polyolefin film's tear strength is related to the material's crystallization time.
  • polyolefin films wherein the polymer crystallizes in the form of oriented lamellae exhibit short crystallization times. Films crystallizing isotropically typically exhibit longer crystallization times and lower tear strength. Crystallization time and its measurement are well-known to those skilled in the art. Crystallization time can be measured, for example, by recording the width of a crystallization exotherm.
  • a nucleating agent is added to the melt in order to decrease crystallization time and consequently form a heterogeneous polymer film of high tear strength.
  • nucleating agents capable of increasing tear strength in metallocene-prepared polyethylene films are polymers whose chains can elongate in the machine-direction of the blown film, or alternatively, commercial nucleating agents that can form linear regions of physical gelation oriented in the machine direction of the blown film. According to this model, such nucleating agents provide sites along their backbone for nucleation of the favored lamellae structure during solidification. Lamellae nucleate perpendicular to these elongated or oriented regions, and it is believed that this morphology provides optimum tear strength.
  • sorbitol based nucleating agents are effective tear- strength improvers because they naturally form physical gels in the melt.
  • Ethylene-based nucleating agents of a higher density than the parent polymer exhibit tear strength improvement as well.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Organic Chemistry (AREA)
  • Compositions Of Macromolecular Compounds (AREA)
  • Manufacture Of Macromolecular Shaped Articles (AREA)

Abstract

L'invention a pour but d'augmenter la résistance au déchirement de films polyéthylène préparés à l'aide de métallocènes et soufflés à partir d'une fusion. Le procédé de l'invention consiste à ajouter à la fusion une quantité efficace d'un agent de nucléation, choisi dans le groupe constitué par dibenzylidène sorbitol, paraméthyle ou diméthyle dibenzylidène sorbitol, et des copolymères greffés d'acide acrylique ou anhydride maléique/éthylène, ainsi que des mélanges de ces substances.
PCT/US1999/015758 1998-07-14 1999-07-13 Procede de reduction du dechirement de films souffles et a base de polyolefine WO2000004090A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU49885/99A AU4988599A (en) 1998-07-14 1999-07-13 Method for reducing tearing in blown polyolefin films

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US11507798A 1998-07-14 1998-07-14
US09/115,077 1998-07-14

Publications (1)

Publication Number Publication Date
WO2000004090A1 true WO2000004090A1 (fr) 2000-01-27

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Application Number Title Priority Date Filing Date
PCT/US1999/015758 WO2000004090A1 (fr) 1998-07-14 1999-07-13 Procede de reduction du dechirement de films souffles et a base de polyolefine

Country Status (2)

Country Link
AU (1) AU4988599A (fr)
WO (1) WO2000004090A1 (fr)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6649694B2 (en) 2001-12-21 2003-11-18 Eastman Chemical Company Process for producing ethylene-α-olefin interpolymer films
EP1746187A1 (fr) * 2005-07-18 2007-01-24 DSM IP Assets B.V. Fil multifilament en polyéthylène
JP2012111883A (ja) * 2010-11-26 2012-06-14 Shachihata Inc ポリオレフィン樹脂組成物及びポリオレフィン樹脂用造核剤マスターバッチ
WO2015068865A1 (fr) * 2013-11-05 2015-05-14 주식회사 두본 Composition d'additif comprenant du lubrifiant
US9278487B2 (en) 2006-05-16 2016-03-08 Basf Se Mono-and multi-layer blown films
CN116178765A (zh) * 2023-04-27 2023-05-30 汕头市鑫瑞奇诺包装材料有限公司 一种流延成型的低水蒸气透过率聚乙烯膜及其制备方法

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0276570A2 (fr) * 1986-12-29 1988-08-03 Du Pont Canada Inc. Procédé de fabrication de pellicules à partir de mélanges de polyoléfines
WO1995013317A1 (fr) * 1993-11-08 1995-05-18 Mobil Oil Corporation Composition comprenant un melange d'un polymere ou d'un copolymere d'ethylene avec du sorbitol ou un derive de sorbitol

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0276570A2 (fr) * 1986-12-29 1988-08-03 Du Pont Canada Inc. Procédé de fabrication de pellicules à partir de mélanges de polyoléfines
WO1995013317A1 (fr) * 1993-11-08 1995-05-18 Mobil Oil Corporation Composition comprenant un melange d'un polymere ou d'un copolymere d'ethylene avec du sorbitol ou un derive de sorbitol

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6649694B2 (en) 2001-12-21 2003-11-18 Eastman Chemical Company Process for producing ethylene-α-olefin interpolymer films
EP1746187A1 (fr) * 2005-07-18 2007-01-24 DSM IP Assets B.V. Fil multifilament en polyéthylène
WO2007009563A1 (fr) * 2005-07-18 2007-01-25 Dsm Ip Assets B.V. Fibre de polyethylene a plusieurs filaments
US9278487B2 (en) 2006-05-16 2016-03-08 Basf Se Mono-and multi-layer blown films
US9732198B2 (en) 2006-05-16 2017-08-15 Basf Se Mono- and multi-layer blown films
JP2012111883A (ja) * 2010-11-26 2012-06-14 Shachihata Inc ポリオレフィン樹脂組成物及びポリオレフィン樹脂用造核剤マスターバッチ
WO2015068865A1 (fr) * 2013-11-05 2015-05-14 주식회사 두본 Composition d'additif comprenant du lubrifiant
CN116178765A (zh) * 2023-04-27 2023-05-30 汕头市鑫瑞奇诺包装材料有限公司 一种流延成型的低水蒸气透过率聚乙烯膜及其制备方法
CN116178765B (zh) * 2023-04-27 2023-06-30 汕头市鑫瑞奇诺包装材料有限公司 一种流延成型的低水蒸气透过率聚乙烯膜及其制备方法

Also Published As

Publication number Publication date
AU4988599A (en) 2000-02-07

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