Classifications

• • 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
  • C08L23/10—Homopolymers or copolymers of propene
  • C08L23/12—Polypropene
• • 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
  • C08F210/04—Monomers containing three or four carbon atoms
  • C08F210/06—Propene
• • 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
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F297/00—Macromolecular compounds obtained by successively polymerising different monomer systems using a catalyst of the ionic or coordination type without deactivating the intermediate polymer
  • C08F297/06—Macromolecular compounds obtained by successively polymerising different monomer systems using a catalyst of the ionic or coordination type without deactivating the intermediate polymer using a catalyst of the coordination type
  • C08F297/08—Macromolecular compounds obtained by successively polymerising different monomer systems using a catalyst of the ionic or coordination type without deactivating the intermediate polymer using a catalyst of the coordination type polymerising mono-olefins
• • 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
  • C08F297/00—Macromolecular compounds obtained by successively polymerising different monomer systems using a catalyst of the ionic or coordination type without deactivating the intermediate polymer
  • C08F297/06—Macromolecular compounds obtained by successively polymerising different monomer systems using a catalyst of the ionic or coordination type without deactivating the intermediate polymer using a catalyst of the coordination type
  • C08F297/08—Macromolecular compounds obtained by successively polymerising different monomer systems using a catalyst of the ionic or coordination type without deactivating the intermediate polymer using a catalyst of the coordination type polymerising mono-olefins
  • C08F297/083—Macromolecular compounds obtained by successively polymerising different monomer systems using a catalyst of the ionic or coordination type without deactivating the intermediate polymer using a catalyst of the coordination type polymerising mono-olefins the monomers being ethylene or propylene
• • 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
  • C08L23/10—Homopolymers or copolymers of propene
• • 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
  • C08F110/00—Homopolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond
  • C08F110/02—Ethene
• • 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
  • 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
  • C08L23/16—Ethene-propene or ethene-propene-diene copolymers
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
  • Y02P20/00—Technologies relating to chemical industry
  • Y02P20/50—Improvements relating to the production of bulk chemicals
  • Y02P20/52—Improvements relating to the production of bulk chemicals using catalysts, e.g. selective catalysts

Definitions

• This invention is in the field of thermoplastic polyolefins and more specifically reactor grade thermoplastic polyolefins (RTPO).
• RTPO reactor grade thermoplastic polyolefins
• the invention is further directed to RTPOs having high flowability and excellent surface quality, when molded into articles of manufacture, especially for automotive applications, a process for producing them and their use.
• the invention is related to the use of a special Ziegler-Natta procatalyst, which contains a trans-esterification product of a lower alcohol and a phthalic ester in combination with a special external donor for the production of RTPOs with high flowability and excellent surface quality.
• TPOs Thermoplastic polyolefins
• elastomer Thermoplastic polyolefins
• TPOs have many desirable properties, e.g. lightweight, durability, low costs, etc., that make them an attractive material for the construction of many interior and exterior automotive parts.
• the second which is commonly referred to as “reactor grade TPO” (RTPO) and is more economical to produce than compound grade TPO, is made by first polymerizing propylene to polypropylene and then polymerizing elastomer components, such as ethylene and propylene, in the presence of the polypropylene.
• RTPO reactor grade TPO
• the RTPOs are known to be suitable for injection molding to produce large, shaped articles, for example for automotive applications, especially bumpers.
• Tigerstripes are a common problem for surface quality respectively appearance in plastic industry.
• Tigerstripes as known in the plastic industry, describe a visible periodic inhomogeneity in surface gloss. Usually these are alternating dull (or rough) and glossy (or smooth) areas on the surface of injection molded or extruded plastic parts, which surface should be glossy (or smooth) all over.
• the RTPOs exhibit as high values of melt flow rate (MFR) as possible in order to improve processability of the RTPOs for injection molding.
• MFR melt flow rate
• WO 2004/000899 describes reactor grade thermoplastic polyolefins on the basis of a polypropylene matrix material including bimodal rubber compositions, whereby the two rubber parts have differentiated Mw (respectively intrinsic viscosity IV) and the low IV rubber is ethylene rich.
• RTPOs are produced in a multistage process comprising at least one slurry reactor and two gas phase reactors.
• a particularly preferred catalyst system is, according to WO 2004/000899, a high yield Ziegler-Natta catalyst having a catalyst component, a cocatalyst and optionally an external donor, or a metallocene catalyst, having a bridged structure giving high stereoregularity and which, as an active complex, is impregnated on a carrier. No further details regarding the used catalyst and external donor are given.
• the RTPOs produced according to WO 2004/000899 show improved surface toughness in terms of scratch resistance and can be used for producing car interiors and exteriors, like bumpers, dashboards and the like, where improved scratch resistance properties are needed.
• the RTPOs exhibit an MFR of at most 13.2 g/10 min.
• EP 1 600 480 describes an improved propylene polymer composition on the basis of a polypropylene matrix material with an MFR in accordance with ISO 1133 (230° C., 2.16 kg) ⁇ 80 g/10 min, including bimodal rubber compositions, whereby the two rubber parts have differentiated Mw (IV) and the low IV rubber is ethylene rich.
• the RTPO is mixed with an elastomeric ethylene-1-octene copolymer, having an ethylene content of at least 80 mol % and having a MFR in accordance with ISO 1133 (190° C., 2.16 kg) of 3-100 g/10 min, and with an inorganic filler.
• elastomeric ethylene-1-octene copolymer having an ethylene content of at least 80 mol % and having a MFR in accordance with ISO 1133 (190° C., 2.16 kg) of 3-100 g/10 min
• ISO 1133 190° C., 2.16 kg
• the RTPO is produced in a multistage process using a Ziegler-Natta catalyst or a metallocene.
• a Ziegler-Natta catalyst or a metallocene.
• ZN104 commercially available from LyondellBasell
• triethylaluminium as cocatalyst and dicyclopentyldimethoxysilane as external donor are used.
• This object was achieved by using a special Ziegler-Natta procatalyst which contains a transesterification product of a lower alcohol and a phthalic ester in combination with a special external donor.
• this special Ziegler-Natta procatalyst in combination with a special external donor can be used for the production of a great variety of RTPOs with high flowability and excellent quality, like RTPOs on the basis of a polypropylene matrix including cross-bimodal rubber compositions, nucleated or non-nucleated RTPOs, with different multistage processes, like Borstar® from Borealis or Spheripol® from LyondellBasell.
• the present invention is therefore directed to reactor grade thermoplastic polyolefins with high flowability and excellent surface quality comprising
• the polymer matrix (A) of the reactor grade thermoplastic polyolefins (RTPOs) according to the invention must be a polypropylene matrix (A), which is in the following called propylene matrix (A).
• the propylene matrix (A) can be a propylene homopolymer, a propylene copolymer or mixtures thereof, like a homo/random copolymer. However it is preferred that the propylene matrix (A) is a propylene homopolymer.
• the expression homopolymer used in the instant invention relates to a polypropylene that consists substantially, i.e. of at least 97 wt %, preferably of at least 98 wt %, more preferably of at least 99 wt %, still more preferably of at least 99.8 wt % of propylene units. In a preferred embodiment only propylene units in the propylene homopolymer are detectable.
• the propylene matrix (A) comprises a propylene copolymer or is a homo/random propylene copolymer
• the propylene copolymer comprises monomers copolymerizable with propylene, for example comonomers such as ethylene and C 4 to C 20 alpha-olefins, in particular ethylene and C 4 to C 10 alpha-olefins, e.g. 1-butene or 1-hexene.
• the comonomer content in the propylene matrix is in such a case preferably relatively low, i.e. up to 4.0 wt %, more preferably 0.1 to 3.0 wt %, still more preferably 0.2 to 2.0 wt %, yet more preferably 0.3 to 1.0 wt %.
• the propylene matrix (A) can be unimodal or multimodal, like bimodal. However it is preferred that the propylene matrix (A) is unimodal. Concerning the definition of unimodal and multimodal, like bimodal, it is referred to the definition below.
• the matrix When the matrix is unimodal with respect to the molecular weight distribution, it may be prepared in a single stage process e.g. a slurry or gas phase process in a slurry or gas phase reactor. Preferably, the unimodal matrix is polymerized as a slurry polymerization.
• the unimodal matrix may be produced in a multistage process using at each stage process conditions which result in similar polymer properties.
• propylene matrix (A) comprises two or more different propylene polymers these may be polymers with different monomer make up and/or with different molecular weight distributions. These components may have identical or differing monomer compositions and tacticities.
• the polymer matrix (A) has a rather high melt flow rate (MFR), i.e. a rather low molecular weight.
• MFR melt flow rate measured under a load of 2.16 kg at 230° C.
• the propylene matrix (A) has an MFR (230° C.) equal to or above 200 g/10 min and up to 500 g/10 min.
• the elastomeric copolymers B and C must fulfill some properties so that the desired results can be achieved.
• the elastomeric ethylene-propylene copolymer (B) must comprise ethylene in a content of above 50 to 80 wt %, preferably 55 to 75 wt %.
• the elastomeric ethylene-propylene copolymer (B) must have an intrinsic viscosity IV ⁇ 2.8 dl/, preferably ⁇ 2.6 dl/g and more preferably ⁇ 2.4 dl/g.
• the elastomeric ethylene-propylene copolymer (C) must comprise propylene in a content of 50 to 80 wt %, preferably 55 to 75 wt %.
• the elastomeric ethylene-propylene copolymer (C) must have an intrinsic viscosity IV of 3.0 to 6.5 dl/g, preferably 3.2 to 6.0 dl/g and more preferably 3.5 to 6.0 dl/g.
• the elastomeric copolymers (B) and (C) can be unimodal or multimodal, like bimodal. However it is preferred that the elastomeric copolymers (B) and (C) are unimodal. Concerning the definition of unimodal and multimodal, like bimodal, it is referred to the definition below.
• RTPOs comprise
• the MFR (230° C.) of the RTPO is rather high, i.e. above 20 g/10 min, more preferably above 25 g/10 min and most preferably above 30 g/10 min.
• multimodal or “bimodal” or “unimodal” used herein refer to the modality of the polymer, i.e. the form of its molecular weight distribution curve, which is the graph of the molecular weight fraction as a function of its molecular weight.
• the polymer components of the present invention are produced in a sequential step process, using reactors in serial configuration and operating at different reaction conditions. As a consequence, each fraction prepared in a specific reactor will have its own molecular weight distribution. When the molecular weight distribution curves from these fractions are superimposed to obtain the molecular weight distribution of the final polymer, that curve may show two or more maxima or at least be distinctly broadened when compared with curves for the individual fractions.
• the RTPOs of the present invention are produced by multistage process polymerization comprising at least 3 polymerization steps, such as bulk polymerization, gas phase polymerization, slurry polymerization, solution polymerization or combinations thereof.
• the polymerization system can comprise one or more conventional stirred slurry reactors and/or one or more gas phase reactors.
• the reactors used are selected from the group of loop and gas phase reactors and, in particular, the process employs at least one loop reactor and at least two gas phase reactors. It is also possible to use several reactors of each type, e.g. one loop and two or three gas phase reactors, or two loops and two gas phase reactors, in series.
• the process comprises also a prepolymerization with the chosen catalyst system, as described in detail below, comprising the special Ziegler-Natta procatalyst, the special external donor and optionally the cocatalyst.
• the chosen catalyst system as described in detail below, comprising the special Ziegler-Natta procatalyst, the special external donor and optionally the cocatalyst.
• the prepolymerisation is conducted as bulk slurry polymerisation in liquid propylene, i.e. the liquid phase mainly comprises propylene, with minor amount of other reactants and optionally inert components dissolved therein.
• the prepolymerisation reaction is typically conducted at a temperature of 0 to 50° C., preferably from 10 to 45° C., and more preferably from 15 to 40° C.
• the pressure in the prepolymerisation reactor is not critical but must be sufficiently high to maintain the reaction mixture in liquid phase.
• the pressure may be from 20 to 100 bar, for example 30 to 70 bar.
• the catalyst components are preferably all introduced to the prepolymerisation step.
• the solid catalyst component and the cocatalyst can be fed separately it is possible that only a part of the cocatalyst is introduced into the prepolymerisation stage and the remaining part into subsequent polymerisation stages. Also in such cases it is necessary to introduce so much cocatalyst into the prepolymerisation stage that a sufficient polymerisation reaction is obtained therein.
• hydrogen may be added into the prepolymerisation stage to control the molecular weight of the prepolymer as is known in the art.
• antistatic additive may be used to prevent the particles from adhering to each other or the walls of the reactor.
• a slurry reactor designates any reactor, such as a continuous or simple batch stirred tank reactor or loop reactor, operating in bulk or slurry and in which the polymer forms in particulate form.
• “Bulk” means a polymerization in reaction medium that comprises at least 60wt-% monomer.
• the slurry reactor comprises a bulk loop reactor.
• Gas phase reactor means any mechanically mixed or fluid bed reactor.
• the gas phase reactor comprises a mechanically agitated fluid bed reactor with gas velocities of at least 0.2 m/sec.
• the particularly preferred embodiment of the invention comprises carrying out the polymerization in a process comprising either a combination of one loop and two or three gas phase reactors or a combination of two loops and two gas phase reactors.
• a preferred multistage process is a slurry-gas phase process, such as developed by Borealis and known as the Borstar® technology.
• a slurry-gas phase process such as developed by Borealis and known as the Borstar® technology.
• EP 0 887 379, WO 2004/000899, WO 2004/111095, WO 99/24478, WO 99/24479 and WO 00/68315 incorporated herein by reference.
• a further suitable slurry-gas phase process is the Spheripol® process of LyondellBasell.
• the reactor grade thermoplastic polyolefins with high flowability and excellent surface quality according to the invention are produced by using the special Ziegler-Natta procatalysts in combination with a special external donor, as described in detail below, in the Spheripol® or in the Borstar®PP process, more preferably in the Borstar®PP process.
• One preferred multistage process may therefore comprise the steps of:
• a further preferred multistage process may comprise the steps of:
• composition ratios of said first and second ethylene/propylene mixtures are adjusted so that in the first gas phase reactor (respectively second GPR) a propylene rich EPR rubber is produced in the propylene polymer matrix and in the second gas phase reactor (respectively third GPR) an ethylene rich EPR rubber is produced in the propylene polymer matrix.
• a molar H 2 /C 2 ratio between preferably 0.01 to 0.1, more preferably 0.02 to 0.06 should be adjusted in the 1 st GPR (respectively 2 nd GPR) and a molar H 2 /C 2 ratio between preferably 0.15 to 0.6, more preferably 0.20 to 0.4 should be adjusted in the 2 nd GPR (respectively 3 rd GPR) to achieve the desired intrinsic viscosities of the two different rubbers.
• the slurry reactor is operated at temperature of from 40° C. to 110° C., preferably between 50° C. and 100° C., in particular between 60° C. and 90° C., with a pressure in the range of from 20 to 80 bar, preferably 30 to 60 bar, with the option of adding hydrogen in order to control the molecular weight in a manner known per se.
• the reaction product of the slurry polymerization which preferably is carried out in a loop reactor, is then transferred to the subsequent gas phase reactor, wherein the temperature preferably is within the range of from 50° C. to 130° C., more preferably 60° C. to 100° C., at a pressure in the range of from 5 to 50 bar, preferably 8 to 35 bar, again with the option of adding hydrogen in order to control the molecular weight, with the option of adding hydrogen in order to control the molecular weight in a manner known per se.
• the average residence time can vary in the reactor zones identified above.
• the average residence time in the slurry reactor for example a loop reactor, is in the range of from 0.5 to 5 hours, for example 0.5 to 2 hours, while the residence time in the gas phase reactor generally will be from 1 to 8 hours.
• the polymerization may be effected in a known manner under supercritical conditions in the slurry, preferably loop reactor, and/or as a condensed mode in the gas phase reactor.
• the polymerization process enables highly feasible means for producing and further tailoring the propylene polymer composition within the invention.
• the precise control of the polymerization conditions and reaction parameters is within the skill of the art.
• the RTPOs with high flowability and excellent surface quality are obtained by a multistage polymerization process, as described above, in the presence of a catalyst system comprising as component (i) a Ziegler-Natta procatalyst which contains a trans-esterification product of a lower alcohol and a phthalic ester.
• the procatalyst used according to the invention is prepared by
• the procatalyst is produced as defined for example in the patent applications WO 87/07620, WO 92/19653, WO 92/19658 and EP 0 491 566. The content of these documents is herein included by reference.
• the adduct which is first melted and then spray crystallized or emulsion solidified, is used as catalyst carrier.
• the adduct of the formula MgCl 2 *nROH, wherein R is methyl or ethyl and n is 1 to 6, is in a preferred embodiment melted and then the melt is preferably injected by a gas into a cooled solvent or a cooled gas, whereby the adduct is crystallized into a morphologically advantageous form, as for example described in WO 87/07620.
• This crystallized adduct is then used as the catalyst carrier and reacted to the procatalyst useful in the present invention as described in WO 92/19658 and WO 92/19653.
• the crystallized carrier is reacted with TiCl 4 to form a titanised carrier.
• a dialkylphthalate of formula (I) is then added to this titanised carrier.
• the alkoxy group of the phthalic acid ester used comprises at least 5 carbon atoms and may be different or the same.
• the alkoxy group of the phthalic acid ester used comprises at least 8 carbon atoms. More preferably the alkoxy groups R 1 ′ and R 2 ′ are the same.
• dialkylphthalate of formula (I) selected from the group consisting of propylhexylphthalate (PrHP), dioctylphthalate (DOP), di-iso-decylphthalate (DIDP), and ditridecylphthalate (DTDP) is used, yet most preferably the dialkylphthalate of formula (I) is a dioctylphthalate (DOP), like di-iso-octylphthalate or diethylhexylphthalate, in particular diethylhexylphthalate.
• DOP dioctylphthalate
• This adduct is then transesterified at a temperature above 100° C. and advantageously between 130 to 150° C.
• the procatalyst used according to the invention contains 2.5% by weight of titanium at the most, preferably 2.2% by weight at the most and more preferably 2.0% by weight at the most.
• Its donor content is preferably between 4 to 12% by weight and more preferably between 6 and 10% by weight.
• the procatalyst used according to the invention has been produced by using ethanol as the alcohol and dioctylphthalate (DOP) as dialkylphthalate of formula (I), yielding diethylphthalate (DEP) as the internal donor compound.
• DOP dioctylphthalate
• DEP diethylphthalate
• the catalyst used according to the invention is the BC-1 catalyst of Borealis or the catalyst Polytrack 8502, commercially available from Grace.
• the Ziegler-Natta procatalyst can be modified by polymerising a vinyl compound in the presence of the catalyst system, comprising the special Ziegler-Natta procatalyst, an external donor and a cocatalyst, which vinyl compound has the formula:
• R 3 and R 4 together form a 5- or 6-membered saturated, unsaturated or aromatic ring or independently represent an alkyl group comprising 1 to 4 carbon atoms, and the modified catalyst is used for the preparation of the polymer composition.
• the polymerised vinyl compound can act as a nucleating agent.
• the catalyst system used preferably comprises in addition to the special Ziegler-Natta procatalyst an organometallic cocatalyst as component (ii). Accordingly it is preferred to select the cocatalyst from the group consisting of trialkylaluminium, like triethylaluminium (TEA), dialkyl aluminium chloride and alkyl aluminium sesquichloride.
• TAA triethylaluminium
• dialkyl aluminium chloride dialkyl aluminium chloride
• alkyl aluminium sesquichloride alkyl aluminium sesquichloride
• Component (iii) of the catalysts system used is an external donor represented by the formula
• R x and R y can be the same or different a represent a hydrocarbon group having 1 to 12 carbon atoms.
• R x and R y are independently selected from the group consisting of linear aliphatic hydrocarbon group having 1 to 12 carbon atoms, branched aliphatic hydrocarbon group having 1 to 12 carbon atoms and cyclic aliphatic hydrocarbon group having 1 to 12 carbon atoms.
• R x and R y are independently selected from the group consisting of methyl, ethyl, n-propyl, n-butyl, octyl, decanyl, iso-propyl, iso-butyl, iso-pentyl, tert.-butyl, tert.-amyl, neopentyl, cyclopentyl, cyclohexyl, methylcyclopentyl and cycloheptyl. More preferably both R x and R y are the same, yet more preferably both R x and R y are an ethyl group.
• diethylaminotriethoxysilane is used as external donor.
• the external donor may be produced according to the methods disclosed in EP 1 538 167. The content of this document is herein included by reference.
• the current invention also provides a multistage process for producing reactor grade thermoplastic polyolefins using the special catalyst system comprising components (i), (ii) and (iii).
• the catalyst system used comprises
• a further aspect of the invention is therefore the use of a catalyst system comprising
• thermoplastic polyolefin for producing a reactor grade thermoplastic polyolefin with high flowability and excellent surface quality in a multistage process including at least 3 polymerization steps.
• an MFR (230° C.) of the RTPO of above 20 g/10 min, more preferably above 25 g/10 min and most preferably above 30 g/10 min can be reached directly with the use of the above described combination of special Ziegler-Natta procatalyst and external donor represented by the formula Si(OCH 2 CH 3 ) 3 (NR x R y ) without any need of degrading by visbreaking using peroxides.
• the RTPOs according to the invention may comprise conventional adjuvants, such as additives, fillers and reinforcing agents or additional impact modifiers.
• elastomers elastomers, nucleating agents, process and heat stabilisers, UV stabilizers, slip agents, antistatic agents, pigments and other colouring agents including carbon black. Depending on the type of additive, these may be added in an amount of 0.001 to 10 wt % based on the weight of the RTPO.
• the polymer composition includes 1 to 15 wt % based on the weight of the polymer composition, of one or more elastomers.
• suitable elastomers include an ethylene/alpha-olefin random copolymer, an ethylene/alpha-olefin/non-conjugated polyene random copolymer, a hydrogenated block copolymer and other elastic polymers or mixtures thereof.
• Preferred elastomers are elastomeric ethylene-1-octene copolymers.
• the polymer composition includes 0.05 to 3 wt % based on the weight of the polymer composition of one or more alpha-nucleating agents such as dibenzylidene sorbitol, sodium benzoate, methylen-bis(4,6-di-t-butylphenyl)-phosphate sodium salt (NA-11), aluminium hydroxyl-bis[2,4,8,10-tetrakis(1,1-dimethylethyl)-6-hydroxy-12H-dibenzo-[d,g]-dioxa-phoshocin-6-oxidato] (NA-21) and di(alkyl-benzylidene)sorbitol or mixtures thereof.
• alpha-nucleating agents such as dibenzylidene sorbitol, sodium benzoate, methylen-bis(4,6-di-t-butylphenyl)-phosphate sodium salt (NA-11), aluminium hydroxyl-bis[2,4,8,10-tetrakis(1,1
• the alpha-nucleating agent is usually added in small amounts of 0.0001 to 1 wt %, more preferably 0.001 to 0.7 wt %. Since talc can act both as a nucleating agent and as filler, it can be added in higher amounts. When added as a nucleating agent, talc is preferably added in an amount of 0.05 to 3 wt %, more preferably 0.1 to 2 wt %, most preferably less than 1 wt %, based on the weight of the polymer composition. Further details about these nucleating agents can be found e.g. in WO 99/24479 and WO 99/24501.
• Molding resin formulations comprising the RTPO produced according to the invention may further comprise 5 to 60 wt % of one or more particulate of fibrous reinforcing fillers such as glass fiber or carbon fiber, graphite, carbon black or the like, or fillers such as clay, talc and mineral fillers and the like commonly employed in the trade for the manufacture of molded articles and extruded goods.
• fibrous reinforcing fillers such as glass fiber or carbon fiber, graphite, carbon black or the like, or fillers such as clay, talc and mineral fillers and the like commonly employed in the trade for the manufacture of molded articles and extruded goods.
• the additives are added to the RTPO, which is collected from the final reactor of the series of reactors.
• these additives are mixed into the composition prior to or during the extrusion process in a one-step compounding process.
• a master batch may be formulated, wherein the RTPO is first mixed with only some of the additives.
• a conventional compounding or blending apparatus e.g. a Banbury mixer, a t-roll rubber mill, Buss-co-kneader or a twin screw extruder may be used.
• the polymer materials recovered from the extruder are usually in the form of pellets. These pellets are then preferably further processed, e.g. by injection molding to generate articles and products of the inventive RTPOs.
• RTPO compositions according to the invention may be pelletized and compounded using any of the variety of compounding and blending methods well known and commonly used in the resin compounding art.
• compositions of the current invention are preferably used for the production of molded articles, preferably injection molded articles. Even more preferred is the use for the production of automotive parts, like bumpers, spoilers, fenders, body panels, side bump strips and the like.
• the current invention also provides articles comprising the inventive RTPOs with high flowability and excellent surface quality.
• these articles are produced by injection molding.
• the molded articles manufactured with the RTPO resins prepared according to the invention display excellent surface quality.
• the surface quality of injection molded parts which is determined according to the procedure described in the experimental section, must be “excellent”, i.e. only polymer compositions which can be injection molded without showing any flow mark, solve the problem which is underlying the present invention.
• melt flow rate is measured as the MFR in accordance with ISO 1133 (230° C., 2.16 kg load) for polypropylene and is indicated in g/10 min.
• MFR is an indication of the flowability, and hence the processability, of the polymer. The higher the melt flow rate, the lower the viscosity of the polymer.
• Comonomer content was measured with Fourier transform infrared spectroscopy (FTIR) calibrated with 13 C-NMR.
• FTIR Fourier transform infrared spectroscopy
• a thin film of the sample was prepared by hot-pressing.
• the area of —CH 2 -absorption peak (800-650 cm ⁇ 1 ) was measured with Perkin Elmer FTIR 1600 spectrometer.
• the method was calibrated by ethylene content data measured by 13 C-NMR.
• Flexural modulus was measured according to ISO 178 by using injection molded test specimens as described in EN ISO 1873-2 (80 ⁇ 10 ⁇ 4 mm)
• the xylene soluble fraction (XS) as defined and described in the present invention was determined as follows: 2.0 g of the polymer are dissolved in 250 ml p-xylene at 135° C. under agitation. After 30 minutes, the solution was allowed to cool for 15 minutes at ambient temperature and then allowed to settle for 30 minutes at 25 ⁇ 0.5° C. The solution was filtered with filter paper into two 100 ml flasks. The solution from the first 100 ml vessel was evaporated in nitrogen flow and the residue dried under vacuum at 90° C. until constant weight is reached. The xylene soluble fraction (percent) can then be determined as follows:
• m 0 designates the initial polymer amount (grams)
• m 1 defines the weight of residue (grams)
• v 0 defines the initial volume of solvent taken (250 millilitres)
• v 1 defines the volume of the aliquot taken for determination (analysis sample; 100 millilitres).
• IV intrinsic viscosity
• the tensile modulus was measured according to ISO 572-3 at 1 mm/min and 23° C. Test specimens as described in EN ISO 1873-2 (80 ⁇ 10 ⁇ 4 mm) were used.
• NIS Charpy, notches impact strength
• Shrinkage was measured according to an internal standard using 150 ⁇ 80 ⁇ 2 mm injection molded plaques. Measurements were performed after injection and conditioning at room temperature for at least 96 h in the flow direction and perpendicular to the flow direction. Following conditions were used for injection molding: injection time: 3 s, melt temperature: 240° C., mold temperature: 50° C., hold pressure: from 73 to 23 bars in 10 steps, hold time: 10 s, cooling time: 20 s.
• the fines were determined by sieving the polymer powder according to ASTM D1921-06.
• the screen set consisted of screens having openings of 4,000 mm; 2,800 mm; 2,000 mm; 1,400 mm; 1,000 mm; 0,500 mm; 0,180 mm; 0,106 mm and 0,053 mm.
• the powder passing the 0,180 mm screen was considered as fines.
• Zinc oxide was used as antistat.
• the base resin was produced in a plant having a prepolymerization reactor, a loop reactor and two fluid bed gas-reactors connected in series.
• the catalyst used in the polymerization was prepared according to WO 92/19653 with DOP as dialkylphthalat of the formula (I) and ethanol as alcohol, the cocatalyst was Triethylaluminium (TEA) and as an external donor (D) diethylamino triethoxy silane was used.
• the catalyst system was fed to the slurry reactor, where the polymerisation of the polypropylene homopolymer matrix phase was performed.
• the slurry phase loop reactor was then followed by a first gas phase reactor in series, in which a first elastomeric rubber disperse phase was produced by copolymerisation of propylene with ethylene comonomer.
• the polymerisation temperature in the slurry phase loop reactor was 62° C.
• the temperature in the first gas phase reactor was 80° C.
• the operating temperature in the second gas phase reactor was 80° C.
• the split between loop, 1 st GPR and 2 nd GPR was: 70.5%:17.0%:12.5%
• Values for C 3 /EPR, IV/XS, MFR and XS of the 2 nd Gas phase reactor product are total values for the final RTPO.
• IV/XS EPR 2nd GPR
• IV/XS (EPR 2nd GPR) [( IV total ⁇ w total ) ⁇ ( IV (EPR 1st GPR) ⁇ w 1st GPR )]/ w 2nd GPR
• the IV of the fraction soluble in xylene produced in the 2 nd gas phase reactor was therefore 1.68 dl/g
• C 3 /EPR (EPR 2nd GPR) [( C 3 /EPR total ⁇ w total ) ⁇ ( C 3 /EPR (EPR 1st GPR) ⁇ w 1st GPR )]/ w 2nd GPR
• the C 3 -amount of the EPR produced in the 2 nd gas phase reactor was therefore 33.54 wt %
• Such master curves were generated by determining the C 3 -amount of an EPR produced in the first gas phase reactor of the above described reactor set up using the same catalyst system as described above but different C 2 /C 2 +C 3 ratios, leading to corresponding C 3 -amounts in the EPR. From these master curves an art skilled person can determine the C 3 -amount of the EPR produced in the 2 nd gas phase reactor using a special C 2 /C 2 +C 3 ratio.
• the powder passing a 0.180 mm screen was considered as fines.
• the base resin (RTPO) was initially obtained in powder form.
• the resin together with 10 wt % Tital15 (talc from Ankerport) and 0.1% NA11 as well as 10 wt % of EG8200 (elastomer Engage®8200 from DuPont Dow Elastomers) were pelletized by feeding the blend to a Prism 24twin-screw extruder (Prism Ltd., Staffordshire, UK). The polymer was extruded through a strand die, cooled and chopped to form pellets.
• the filmgate over the whole width had a thickness of 1.4 mm.
• the produced plaques are judged visually by a tester in terms of tigerskin.
• the tigerskin level was assessed by a number between 1 (no flow mark “excellent”) and 5 (a large area of flow marks, “insufficient”) according to FIG. 3.

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