EP0902809A1 - Produit a base de polymere d'ethylene possedant une repartition de poids moleculaire etendue, et preparation et utilisation de ce produit - Google Patents

Produit a base de polymere d'ethylene possedant une repartition de poids moleculaire etendue, et preparation et utilisation de ce produit

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Publication number
EP0902809A1
EP0902809A1 EP97925086A EP97925086A EP0902809A1 EP 0902809 A1 EP0902809 A1 EP 0902809A1 EP 97925086 A EP97925086 A EP 97925086A EP 97925086 A EP97925086 A EP 97925086A EP 0902809 A1 EP0902809 A1 EP 0902809A1
Authority
EP
European Patent Office
Prior art keywords
ethylene polymer
molecular weight
preferentially
process according
blend
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.)
Withdrawn
Application number
EP97925086A
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German (de)
English (en)
Inventor
Bengt Hagström
Aimo Sahila
Jari Äärilä
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Borealis Polymers Oy
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Borealis Polymers Oy
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Filing date
Publication date
Application filed by Borealis Polymers Oy filed Critical Borealis Polymers Oy
Publication of EP0902809A1 publication Critical patent/EP0902809A1/fr
Withdrawn legal-status Critical Current

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    • 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
    • C08F210/00—Copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond
    • C08F210/16—Copolymers of ethene with alpha-alkenes, e.g. EP rubbers
    • 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
    • C08L23/08—Copolymers of ethene
    • C08L23/0807—Copolymers of ethene with unsaturated hydrocarbons only containing more than three carbon atoms
    • C08L23/0815—Copolymers of ethene with aliphatic 1-olefins
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L2205/00—Polymer mixtures characterised by other features
    • C08L2205/02—Polymer mixtures characterised by other features containing two or more polymers of the same C08L -group
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L2310/00—Masterbatches
    • 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
    • C08L2314/02—Ziegler natta catalyst

Definitions

  • the invention relates to a process for the preparation of a solid ethylene polymer product, containing from 0.0 to 20% by weight of repeating units of a C3-C 10 ⁇ " olefm and having a broad molecular weight distribution.
  • the ethylene polymers having narrow molecular weight distribution are not satisfactory, because of the poor melt flow properties and poor processability. Therefore, different approaches have been suggested for manu ⁇ facturing polyethylenes having a broad molecular weight distribution.
  • One approach to widen the molecular weight distribution is to blend a low molecular weight ethyl- ene polymer with a high molecular weight ethylene polymer either mechanically or in solution. More than two ethylene polymers having different molecular weights can also be mixed together.
  • US 5,326,835 discloses a multi-stage - process for producing ethylene polymer having a bimodal and/or broad molecular weight distribution in a multi-step reaction sequence.
  • the first reaction step is performed in a loop reactor and one or more subsequent steps are performed in one or more gas phase reactors.
  • the molecular weight distribution can be controlled by using different concentrations of hydrogen chain transfer agent and co-monomer in different steps.
  • bimodal and multimodal distribution is generally and in connection with the present invention meant a broad molecular weight distribution produced by blending two or more polymer components with different molecular weights or by polymer ⁇ izing to different molecular weights in a process with two or more reactors in series.
  • Unimodal distribution is obtained with essentially only one molecular weight fraction.
  • the ethylene polymers produced up till now have not had entirely satisfactory properties. This applies for the processability properties in general, and for the melt strength of the unloaded polymer melt during processing in particular. The latter property is important eg. for bubble stability during film blowing and controlled orientation during extrusion, especially the extrusion of ethylene polymer film.
  • the aim of the invention is to produce an ethylene polymer product having both better processability and melt strength.
  • the ethylene polymer product should have low melt viscosity under high shearing forces and high melt viscosity under low shearing forces.
  • EP 0 700 769 discloses the treatment of polyethylene with a broad molecular weight distribution using oxygen or oxygen containing gas.
  • the feeding of oxygen into a melt porcessing apparatus is uncontrollable and does not result in broadened molecular weight distribution. See page 6, lines 15 and 16 of said EP application.
  • the oxidized polyethylene is preferentially prepared by chromium oxide catalyst.
  • an ethylene polymer product is produced, which contains from 0.0 to 20% by weight of repeating units of a C3-C10 ⁇ -olefms and has a broad molecular weight distribution.
  • step (b) the blend of step (a) is heated and melt processed into a molten ethylene polymer having a fourth average molecular weight and fourth molecular weight distribution; a stabilizer is optionally added in step (b), and
  • step (b) The process according to the invention is substantially characterized in that in the above step (b), the blend of step (a) is subjected to controlled free radical reactions so that the fourth average molecular weight is higher than, or approximately equal to, the third average molecular weight, and the fourth molecular weight distribution is broader than the third at least bimodal molecular weight distribution.
  • the average molecular weights and the molecular weight distributions can be measured and expressed by any conventional method applied to ethylene polymers products.
  • the average molecular weights are measured and expressed as melt flow rates MFR 1 ⁇ where i refers to the first, second, third and fourth average molecular weight and m refers to the load of the piston used for measuring the MFRs, which load in the following examples generally is 5.0 kg (ISO 1133), the molecular weight distributions are expressed as the flow rate ratios, FRR ⁇ l/ ⁇ , i.e.
  • MFR Melt Flow Rate
  • Flow Rate Ratio (FRR m l/ m 2) is meant the ratio between the melt flow rate (MFR m l) measured at a standard temperature and witi standard die dimensions using a heavy load ( m l)and the melt flow rate (MFR m 2) measured at the same temperature with the same die dimensions using a light load (m2).
  • the heavy load ml is 21.6 kg and the light load m ⁇ is 5.0 kg or 2.16 kg (ISO H33).
  • step (b) of the claimed process the blend of step (a) is heated, melt processed into a molten ethylene polymer, and subjected to free radical reactions.
  • the melt processing equipment for step (b) can be any suitable heated machine which melts the blend of step (a) and exerts shearing forces upon the blend.
  • Such machines are e.g. extruders, calenders, kneaders, mixers, etc., preferentially extruders.
  • the free radicals inducing reagent can be introduced to any part of the machine such as the feed zone, melting zone and/or conveying zone of an extruder.
  • the preferred mechanical energy of the machine is 100 to 500 kWh per g of polymer blend.
  • step (a) is subjected to free radical reactions to such an extent that me relative MFR5 decreases, that is -(MFR 5 - MFR 3 5):MFR 3 5, is from 5 to 100%, preferentially from 10 to 80%.
  • the upper limit is not to be interpreted as a limitation, but it has only a descriptive function, which is based on the experimental results obtained in connection with the present invention. Anyhow, it appears that the melt viscosity increases by several tens of per cent, which means that me controlled radical essentially lead to the combination of radical fragments into larger ethylene polymer molecules than before the free radical reactions. Indeed, it was very surprising that the subjection of an ethylene polymer having a bimodal or multimodal distribution to free radical reactions would lead to an increase of the molecular weight and thus to an increase in the melt strength and the mechanical properties of the product.
  • step (b) of the claimed process the blend of step (a) is preferentially subjected to controlled free radical reactions so that the relative broadening (increase) of the molecular weight distribution expressed as +(FRR ⁇ 2i/5 - FRR 3 2l/5):FRR 3 21/5 is from 5 to 100%, most preferentially from 10 to 80%.
  • the molecular weight distribution would be broadened by free radical reactions, since the above mentioned controlled rheology process for polypropylene led to a narrowing of the molecular weight distribution and the oxygenation of poly ⁇ ethylene did not influence it.
  • the upper limit of the disclosed flow rate ratios are not to be interpreted as limiting the scope of protection, but is only based on the embodiment of the examples.
  • Free radical reactions can be effected in many ways. Firstly, free radicals may be generated from initiators in diverse ways, among which thermal or photochemical intermolecular bond cleavage, redox reactions, and photochemical hydrogen abstraction are the most common, but other processes such as the use of ⁇ -radiation or electron beams find application. Free radicals can also be generated by means of reaction of the ethylene polymer blend by means of thermal decomposition with or without the presence of oxygen. Thermal treatment is a suitable method, especially if unstabilized polyethylene is used or if the used ethylene polymer is destabilized during the treatment.
  • azo- compounds such as azobisisobutyronitrile (ALBN), peroxy compound such as diacyl peroxides, acetyl alkylsulfonyl peroxides, dialkyl peroxydicarbonates, / -alkyl- peroxyesters, 00-/er/-alkyl O-alkyl monoperoxycarbonates, di(rert-alkylperoxy)- ketals, di(/e -alkyl)peroxides, tert-a ⁇ ky ⁇ hydroperoxides, and ketone peroxides, redox initiators, etc.
  • the half life of the thermal initiators used during 10 h is from 38 to 172°C, preferentially from 54 to 128°C.
  • diacylperoxides such as dibenzoyl peroxide BPO, di(2,4-dichloro- benzoyl) peroxide, diacetyl peroxide, dilauroyl peroxide, didecanoyl peroxide, diisononanoyl peroxide and succinic acid peroxide; commercial peroxy esters, such as di-terf-butyl diperoxyphthalate, tert-butyl perbenzoate, tert-but l peracetate, tert- amyl perbenzoate, 2,5-di(benzoylperoxy)-2,5-dimethylhexane, tert-butyl peroxyma- leic acid, ter/-butyl peroxyisobutyrate, tert-butyl peroxy-2-ethylhexanoate(tert-butyl peroctoate), /er/--
  • Preferred peroxy initiators are chosen from: 2,5-dimethyl-2,5-di(t ⁇ r/- butylper- oxy)hexyne-3; 2,5-dimethyl-2,5-di(ter/-butylperoxy)hexane; di-/er/-butyl peroxide; di-/er/-butylperoxyisopropyl benzene; /e/-/-butylcumy .peroxide; dicumylperoxide; 3,3,6,6,9,9-hexamethyl-l,2,4,5-tetracyclononane; 4,4-di-/er/-butyl peroxy-n-butyl- valerate; 1,1-di-t ⁇ rf-butyl peroxycyclohexane; /er/-butyl peroxybenzoate; dibenzoyl peroxide; di(2,4-dichlorobenzoyl)peroxide; di(p-chloro
  • radical generation can be controlled experimentally with normal work and without inventive skill. What the skilled person did not know was that it was possible to increase the molecular weight and broaden the molecular weight distribution thus improving the melt strength and mechamcal properties of bi- and multimodal ethylene polymers by controlled free radical reactions during melt processing. Uncontrolled free radical treatment leads to decomposition and smaller molecular weight polymer. Oxygenation leads to crosslinking and unchanged molecular weight and distribution thereof.
  • step (b) the heating and melt processing of step (b) is preferentially carried out at 180°C to 290°C, most preferentially from 200°C to 270°C.
  • the amount of generated radicals is naturally also dependent on the amount of initiators added to step (b) of the claimed process.
  • the preferential initial content of initiator or optionally content of initiator left after reaction with an added stabilizer is from 20 ppm to 2000 ppm, most preferentially from 50 ppm to 500 ppm, calculated on the weight of the blend of step (a). Later in step (b), of course, the content of initiator decreases as it decomposes into radicals.
  • the average heating and melt processing time in step (b) of the claimed process has much influence on the generation of free radicals. Depending on the other parameters used, it can vary very much.
  • the average heating and melt processing time in step (b) is preferentially from 0.1 min to 30 min and most preferentially from 0.5 min to 10 min.
  • the blend of step (a) is subjected to free radical reactions by means of free radical initiators.
  • free radical reactions can namely be induced merely by heating the polymer during step (b).
  • the temperature is preferentially from 220°C to 320°C, most preferentially from 240°C to 300°C.
  • the average heating and melt processing time in step (b) is from 0.1 min to 30 min, preferentially from 0.5 min to 10 min.
  • step (a) When generating radicals by means of thermal treatment, it is preferable to use an essentially unstabilized or lightly stabilized blend of step (a) as raw material for step (b) of the claimed process.
  • a stabilizer can be added at the end of step (b), after the needed amount of radical reactions have taken place. It is then added to and mixed with the molten ethylene polymer.
  • Stabilizers antioxidants, UV stabilizers and metal deactivators
  • the antioxidants protect polyolefins against oxidation by controlling molecular weight changes leading to loss of physical and mechamcal properties. Commonly the antioxidants are divided in two groups (primary and secondary antioxidants) according to their function in the polymer.
  • the primary antioxidants (AH) react rapidly with the peroxy radicals and stop the chainbreaking by forming hydroperoxides and stable antioxidant radicals (A ):
  • This (A ) can react further and be regenerated by heat or light:
  • the majority of primary antioxidant for polyolefins are sterically hindered phenols which protect the polymer during processing and improve thermal stability and give lloonngg tteerrmm p prrootteecctitioonn.
  • the secondary antioxidants reduce the unstable hydroperoxides to inert products. In combinations with primary antioxidants they give added stability to the polymer (synergism).
  • the most popular secondary antioxidants are the phosphites, phosphonites and the thioethers. These are so called process stabilizers and the phosphites are the most effective during processing and protect both the polymer and the primary anti ⁇ oxidant (reduce discolouration). Hydrolytically stable phosphites are mainly used.
  • Thioethers are useful only in increasing the long-term heat stability performance of phenolic antioxidants. They can provide cost savings by reducing the level of primary antioxidants.
  • the main antioxidants for polyolefins are often referred to the Ciba-Geigy's Irganox and Irgafos trademarks (also by their competitors).
  • the chemical structures of the antioxidants are viewed in the Table below.
  • Antioxidants for polyolefins chemical structures Sterically hindered phenols:
  • Irganox PS 800 Irganox PS 802
  • UV stabilizers protect the polymer from the degradative attack of UV energy in out- door applications.
  • the UV stabilizers used in polyolefins are classified according to their function in screeners, absorbers and free-radical scavengers.
  • the screeners are pigments absorbing or reflecting UV light. Carbon black and titanium dioxide are the most used.
  • UV absorbers are aromatic compounds which can absorb the UV energy and convert it into heat. They are effective in thick sections.
  • the free-radical scavengers inhibit the propagation through a combination of scavenging and terminating free radicals and decomposing hydroperoxides to harm ⁇ less products.
  • the hindered amine light stabilizers (HALS) belong to this group of UV stabilizers.
  • step (b) it is dependently of the antioxidant fed, preferential in step (b) to add from 0 to 500 ppm of a first stabilizer to the blend of step (a) essentially at the beginning of step (b) and to add from 400 to 1400 ppm of a second stabilizer to the molten ethylene polymer essentially at the end of step (b), the first and second stabilizers being equal or different.
  • the first stabilizer added in step (b) is a different stabilizer than the second stabilizer, most preferentially so, that the first stabilizer is a weak process stabilizer allowing radical reactions partially, whereas the second stabilizer is a strong process stabilizer essentially preventing radical reactions during melt pro- cessing.
  • the bimodal raw material of the heating, melt processing and controlled free radical treatment of step (b) of the claimed process can be produced by essentially two main process steps, namely the mixing of at least two ethylene polymers having different average molecular weights and by polymerizing in a process having at least two internal steps leading to different molecular weights. If necessary, the two methods can be combined in any suitable way to give the right molecular weight distribution for step (b).
  • step (a) of a first ethylene polymer and at least a second ethylene polymer is analyzed more closely.
  • the mixing can be a mechanical mixing of two or more granulates, but is preferentially a melt mixing.
  • step (a) is preferentially a mixing of two molten polymers e.g. by melt processing and compounding equipment such as an extruder.
  • the melt flow ratio MFR ⁇ 2 of the first ethylene polymer is from 50 to 2000 g/10 min, most preferentially from 100 to 1500 g/10 min.
  • their melt flow ratio MFR2, etc 2i is preferentially from 0.05 to 50 g/10 min. most preferentially from 0.10 to 20/10 min.
  • the ratio between the first ethylene polymer and the second ethylene polymer is preferentially between 20:80 and 80:20, most preferentially between 20:80 and 60:40.
  • the present invention relates to the molecular weight and its distribution controlling free radical reaction treatment of any bimodal or multimodal ethylene polymer.
  • the different ethylene polymers disclosed in step (a) of the present process can have the monomer composition of a homo- polymer or a copolymer.
  • the first ethylene polymer has a C3-C jo ⁇ -olefin repeating unit content of 0.0 to 10% by weight, calculated from the weight of the first ethylene polymer.
  • At least one ethylene polymer component of the blend formed in step (a) is an ethylene copolymer containing a small amount of another olefin.
  • the second ethylene polymer has a C3-C 10 ⁇ -olefin, preferentially 1-butene, or 1- hexene, repeating unit content from 1.0 to 25% by weight and most preferentially from 2.0 to 15% by weight.
  • the further ethylene polymer components can be either homo- polymers or copolymers.
  • step (a) is formed by mixing a first ethylene polymer and at least a second polymer
  • the proportion of the first ethylene polymer and the second, etc., ethylene polymer, the MFRl and MFR 2 of said ethylene polymers and the C3-C10 ct-olefin repeating unit content of said ethylene polymers are preferentially such that the MFR 3 21 of the blend obtained in step (a) is between 5 and 50 g/10 min, the-C3-C ⁇ o ⁇ -olefin repeating unit content of the blend from step (a) is from 0.2 to 20% by weight, preferentially 0.5 to 15% by weight, and the FRR 3 21/5 is between 10 and 40, most preferentially so that after step (b), the fourth molecular weight distribution is at least bimodal.
  • step (a) is very important when deterrnining the broadness of the molecular weight distribution of the final ethylene polymer product.
  • step (a) of ethylene polymer raw material for the controlled free radical reactions of step (b) by mixing a first, a second, etc. ethylene polymer was disclosed above.
  • Said raw material, i.e. blend of step (a) can also be prepared by performing a multi-step internal polymerization process. In the polymerization process several substeps are performed, in which the first, lower molecular weight ethylene polymer is prepared by polymerizing in a substep (ai), the second higher molecular weight ethylene polymer is prepared by polymerizing in a substep (a2), and optional further ethylene polymers are prepared by polymerizing in optional further substeps, whereby the ethylene polymer of each step is present in the following step.
  • each substep is such, that ethylene polymers are produced the average molecular weight of which differs so that the end product is bimodal or multimodal.
  • a temperature of 40°C to 120°C is used, and, independently, in substep (a2), a temperature of 60°C to 140°C is used.
  • the polymerizations are typically insertion polymerizations where Ziegler-Natta or single site polymerization catalyst systems are used.
  • a catalyst system is typically used, which is based on at least a tetra- valent titanium compound as procatalyst and an organoaluminum compound as cocatalyst.
  • procatalyst is preferentially based on titanium tetrachloride TiC i, magnesium chloride MgCl2, and an optional inert carrier and/or an optional electron donor compound
  • a typical cocatalyst is a trialkylaluminum compound.
  • Typical catalysts are e.g. prepared according to WO 91/12182 and WO 95/35323 which are herewith included by reference.
  • a preferential single site polymerization catalyst system is that based on a group 4 (IUPAC 1990) metal metallocene an alumoxane.
  • substeps (aj) and (a2) can be performed in any order, preferentially so that the catalyst system added to one substep catalyst system is also used in the next and other optional additional substeps.
  • the most convenient way to regulate the molecular weight during polymerization is to use hydrogen, which acts as a chain-transfer agent by intervening in the insertion step of the polymerization mechanism.
  • a hydrogen amount is used, leading to a melt index MFR ⁇ of the first ethylene polymer of from 50 to 2000 g/10 min., most preferentially from 100 to 1500 g/10 min., when substep (aj) is performed first.
  • the properties of the first, second etc. ethylene polymers forming the blend of step (a) also depend on the use of minor amounts of an ⁇ -olefin, which is not ethylene.
  • ⁇ -olefin which is not ethylene.
  • no or a small amount of C3-C 0 ⁇ -olefin is used, so that the first ethylene polymer has a C3-C10 ⁇ -olefin repeating unit content of 0.0 to 14
  • the second ethylene polymer has a C3-C10 ⁇ -olefin, preferentially 1-butene or 1-hexene, repeating unit content of from 1.0 to 25% by weight, preferentially from 2.0 to 15.0% by weight, of at least the second ethylene polymer.
  • the ratio between the first produced ethylene polymer, having the MFR 2 defined above, and the second produced ethylene polymer, having a lower MFR is between 20:80 and 80:20, preferentially between 20:80 and 60:40.
  • it is suitable to use more of the second ethylene polymer than the first ethylene polymer.
  • step (a) a blend of step (a) is produced, which is most suitable for the melt processing free radical reactions of step (b) and gives a useful final ethylene polymer product.
  • reaction temperature, catalyst system, portion of C3-C10 ⁇ -olefin, amount of hydrogen, and ratio between the first olefin polymer and the second olefin polymer produced are regulated so that MFR 3 2l of the blend of step (a) is between 5 and 50 g/10 min.
  • the C3-C 10 ⁇ -olefin repeating unit content of the blend of step (a) is from 0.2 to 20% by weight, preferentially from 0.5 to 15.0% by weight
  • the FFR 3 defined as MFR 3 2l/MFR 3 5 is between 10 and 40, preferentially so that after step (b), the fourth molecular weight distribution is at least bimodal, that is, bimodal or multimodal.
  • the present invention also relates to an ethylene polymer product and preferentially a film material product, which contains from 0.0 to 20% by weight of repeating units of a C3-C10 ⁇ -olefin and having a broad molecular weight distribution.
  • the ethylene polymer product is characterized by that it has been prepared by means of the above described process.
  • the ethylene polymer product according to the invention is very processable and has an extraordinary good melt strength. There ⁇ fore it is particularly suitable for extrusion applications and especially film blowing, cast-line extrusion, pipe-coating, extrusion coating, as well as in blow moulding applications.
  • the properties of bimodal and multimodal resins can according to the invention be further improved during compounding step by controlled treating with radical reactions, i.e. by tailoring the molecule structure of the base material. Tailoring is then based on radical reactions.
  • the reactions can be initiated by peroxides or by using heat and no or a reduced amount of stabilizers in the extruder. The absence or reduced amounts of stabilizers make the controlled peroxide reactions possible in the compounding machine.
  • the tailoring reactions increase the amount of high Mw molecules, which can be seen in the increased zero shear rate viscosity (lower MFR values).
  • Balanced application properties can be obtained by fme-tuning the tailoring.
  • the elasticity of the ethylene polymer material is increased. This gives better melt strength and processability on film blowing line. Another improvement is a more balanced orientation, which gives better tear strength in the machine direction and thus improves the overall tear strength. Increased elasticity also improves the neck-in and draw down properties on different extrusion applications and gives better stability for the broadness of film on cast-line, pipe coating, extrusion coating etc.
  • the weight swell is an important parameter on blow molding lines.
  • weight swell is meant the weight of a blow article compared to a reference, using constant parrison length. To have easy processability it has to be adjusted to a suitable level. Tailoring gives a possibility to fine-tune, when necessary, the flow properties and weight swell, which is a function of die swell and sagging. Tailoring decreases die swell and on the other hand the low zero shear rate viscosity obtained results in less sagging and also slower rate of swelling.
  • the powder from the above polymerization was compounded with different peroxide contents on Werner & Pfleiderer ZSK-30 extruder.
  • the peroxide was 2,5- dimethyl-2,5-di(tert.butylperoxy)-hexane (Luperox 101) and it was added as a master batch in the same powder.
  • the master batch was made in a Papenmeyer mixer.
  • the samples were evaluated by measuring the melt flow and by blowing film on a lab scale Collin G.M.B.H. 30 D extruder.
  • the running conditions on film line were barrel temperature 170° ... 230°, screw speed 50 rpm, output 3.7 kg/h and frost line 300 mm.
  • the effective blow up ratio (BUReff) means the ratio between the bubble diameter and the narrowest diameter of the film neck.
  • the BUReff value is used to describe elasticity and bubble stability. The higher the BUReff value, the better is the film material.
  • the powder from the above polymerization was compounded on Werner & Pfleiderer ZSK-30 extruder without and with peroxide addition.
  • the peroxide was bis(tert.butylperoxyisopropyl)benzene (Perkadox 14S) and it was added as a master batch in the same powder.
  • the master batch was made in a Pappenmeyer mixer.
  • the shear thinning index (SHI) measured at low shear and at high shear is used to describe the broadness of molecular weight distribution. The larger the SHI, the broader is the distribution.
  • the example shows the possibility to adjust the processability of bimodal polyolefin material on blow molding lines by molecular weight tailoring.
  • the weight swell is an important parameter on blow molding lines. To have easy processability it has to be adjusted to a suitably low level. Tailoring gives a possibility to fine-tune, when necessary, the flow properties and weight swell, which is a function of die swell and sagging. Tailoring decreases die swell and on the other hand the low zero shear rate viscosity results in less sagging and also slower rate of swelling.
  • Example 3 (including comparative example)
  • the low content of stabilizer in the beginning of the extruder gives possibilities for tailoring reactions.
  • the needed stabilizers for the end product can be fed in to the latter part of the extruder.
  • Bimodal polyethene (C) was polymerized with Ziegler-Natta type catalyst prepared according to WO 95/35323 in one loop and one gas phase reactor which are operated in series.
  • the catalyst was prepolymerized before feeding into the loop reactor.
  • the prepolymerization degree was 130 g/g.
  • Ethene was polymerized with 1-butene and hydrogen in the gas phase reactor.
  • the production rate split of loop and gas phase reactors was 42% / 58%.
  • the final product MFR21 6.8 and density 945 kg/m 3 .
  • test materials were film blowed on Alpine film blowing line having 65 mm screw diameter.
  • the used blow up ratio was 3.5.
  • the neck height was 8 * die diameter and film thickness was 15 ⁇ m.
  • the example clearly shows improved bubble stability during film blowing and more balanced orientation which can be seen as better balance between machine direction (MD) and transverse direction tear strength (TD) for the film.
  • MD machine direction
  • TD transverse direction tear strength
  • Example 4 Bimodal polyethene (D) was polymerized with said Ziegler-Natta type catalyst in one loop and one gas phase reactor which are operated in series. Ethene was 20
  • Bimodal polyethene (E) was polymerized with said Ziegler-Natta type catalyst in one loop and one gas phase reactor which are operated in series.
  • the catalyst was prepolymerized before feeding into the loop reactor.
  • the prepolymerization degree was 100 g/g.
  • Ethene was polymerized with 1-butene and hydrogen in the gas phase reactor.
  • the production rate split of loop and gas phase reactors was 43% / 57%.
  • the final product MFR21 25 and density 922 kg/m 3 .
  • test materials were film blowed on Reitenhauser film blowing line having 150 mm die diameter.
  • the used blow up ratio was 3.
  • the neck height was 8 * die diameter and film thickness was 25 ⁇ m.

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Abstract

Les produits à base de polymère d'éthylène qui possèdent une répartition de poids moléculaire bimodale ou multi-modale, présentent certes de bonnes propriétés mécaniques et d'aptitude au traitement, mais ces dernières demeurent toutefois insuffisantes. Ces produits à base de polymère d'éthylène bimodal ou multi-modal ont pu être améliorés en effectuant les étapes suivantes. (a) On forme tout d'abord un mélange comprenant les éléments suivants: un premier polymère d'éthylène qui possède un premier poids moléculaire moyen et une première répartition de poids moléculaire; et au moins un deuxième polymère d'éthylène qui possède un deuxième poids moléculaire moyen supérieur à celui du premier, ainsi qu'une deuxième répartition de poids moléculaire, ce qui permet d'obtenir un mélange possédant un troisième poids moléculaire moyen et une troisième répartition de poids moléculaire qui est au moins bimodale. On procède ensuite (b) au chauffage et à la fusion du mélange obtenu lors de l'étape (a), ceci de manière à obtenir un polymère d'éthylène fondu qui possède un quatrième poids moléculaire moyen et une quatrième répartition de poids moléculaire. On procède enfin (c) au refroidissement et à la solidification du polymère d'éthylène fondu de manière à obtenir le produit à base de polymère d'éthylène voulu. Lors de l'étape (b), le mélange obtenu au cours de l'étape (a) est soumis aux réactions régulées de radicaux libres, ceci de manière à ce que le quatrième poids moléculaire moyen soit supérieur ou à peu près égal au troisième, et à ce que la quatrième répartition de poids moléculaire soit plus étendue que la troisième qui est au moins bimodale.
EP97925086A 1996-06-07 1997-06-06 Produit a base de polymere d'ethylene possedant une repartition de poids moleculaire etendue, et preparation et utilisation de ce produit Withdrawn EP0902809A1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
FI962366A FI108452B (fi) 1996-06-07 1996-06-07 Etyleenipolymeerituote, jolla on leveõ moolimassajakauma, sen valmistus ja kõytt÷
FI962366 1996-06-07
PCT/FI1997/000353 WO1997047682A1 (fr) 1996-06-07 1997-06-06 Produit a base de polymere d'ethylene possedant une repartition de poids moleculaire etendue, et preparation et utilisation de ce produit

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EP0902809A1 true EP0902809A1 (fr) 1999-03-24

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Country Link
EP (1) EP0902809A1 (fr)
FI (1) FI108452B (fr)
RU (1) RU2167900C2 (fr)
WO (1) WO1997047682A1 (fr)

Families Citing this family (22)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FI111372B (fi) * 1998-04-06 2003-07-15 Borealis Polymers Oy Olefiinien polymerointiin tarkoitettu katalyyttikomponentti, sen valmistus ja käyttö
GB9919718D0 (en) * 1999-08-19 1999-10-20 Borealis As Process
EP1231238A1 (fr) * 2001-02-08 2002-08-14 Borealis Technology Oy Composition de polyethylene multimodale pour support de cable à fibres optiques
SE0201173L (sv) * 2002-04-18 2003-10-19 Borealis Tech Oy Förfarande för strålningsbehandling av etylenpolymerer
US6870010B1 (en) 2003-12-01 2005-03-22 Univation Technologies, Llc Low haze high strength polyethylene compositions
US7288596B2 (en) 2003-12-22 2007-10-30 Univation Technologies, Llc Polyethylene compositions having improved tear properties
US7193017B2 (en) 2004-08-13 2007-03-20 Univation Technologies, Llc High strength biomodal polyethylene compositions
US7312279B2 (en) 2005-02-07 2007-12-25 Univation Technologies, Llc Polyethylene blend compositions
US7642330B2 (en) 2005-03-31 2010-01-05 Exxonmobil Chemical Patents Inc. Method of selecting polyolefins based on rheological properties
EP1739110B2 (fr) 2005-06-30 2014-07-23 Borealis Technology Oy Composition de polyéthylène avec processabilité améliorée
DE602007003953D1 (de) * 2007-04-25 2010-02-04 Borealis Tech Oy Rohr mit gegen extrem langsames Risswachstum beständigem Polyethylen
US8138264B2 (en) 2007-05-04 2012-03-20 Fina Technology, Inc. Bimodal polyethylene resins that have high stiffness and high ESCR
EP2030993A1 (fr) * 2007-09-03 2009-03-04 INEOS Manufacturing Belgium NV Procédé de polymérisation de phase en suspension
EP2030994A1 (fr) * 2007-09-03 2009-03-04 INEOS Manufacturing Belgium NV Procédé de polymérisation de phase en suspension
EP2033976A1 (fr) * 2007-09-03 2009-03-11 INEOS Manufacturing Belgium NV Procédé de polymérisation de phase en suspension
EP2072587B1 (fr) * 2007-12-20 2020-06-03 Borealis Technology Oy Tuyaux revêtus dotés de propriétés mécaniques améliorées à hautes températures et procédé de fabrication correspondant
EP2072589A1 (fr) * 2007-12-20 2009-06-24 Borealis Technology Oy Procédé pour le revêtement d'un tuyau à grand rendement utilisant un copolymère d'éthylène multimodal et tuyaux revêtus correspondants
EP2072588B1 (fr) * 2007-12-20 2012-10-10 Borealis Technology Oy Procédé pour le revêtement d'un tuyau à grand rendement utilisant un copolymère d'éthylène multimodal et tuyaux revêtus correspondants
EP2072586B1 (fr) * 2007-12-20 2020-11-11 Borealis Technology Oy Tuyaux revêtus dotés de propriétés mécaniques améliorées et procédé de fabrication correspondant
ES2831165T3 (es) 2011-12-29 2021-06-07 Ineos Olefins & Polymers Usa Resinas de polietileno de alta densidad bimodales y composiciones con propiedades mejoradas y métodos de preparación y uso de las mismas
EP2995631A1 (fr) 2014-09-12 2016-03-16 Borealis AG Procédé de production de copolymères greffés à un squelette de polyoléfine
CN106715067A (zh) 2014-12-08 2017-05-24 博里利斯股份公司 丙烯共聚物粒料的制备方法

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5073598A (en) * 1989-06-21 1991-12-17 Mobil Oil Corporation Method for improving the processing characteristics of polyethylene blends
US5405917A (en) * 1992-07-15 1995-04-11 Phillips Petroleum Company Selective admixture of additives for modifying a polymer

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO9747682A1 *

Also Published As

Publication number Publication date
FI962366A0 (fi) 1996-06-07
FI108452B (fi) 2002-01-31
FI962366A (fi) 1997-12-08
RU2167900C2 (ru) 2001-05-27
WO1997047682A1 (fr) 1997-12-18

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