Patent Description:
Optimization of blown films based on copolymers of polypropylene (PP) is a multidimensional problem. Many attempts have been made for optimizing the materials suitable for film. <CIT> describes a biaxially oriented PP (BOPP) film made from Ziegler-Natta catalyst derived copolymers comprising at least <NUM> wt. -% ethylene, particularly <NUM> to <NUM> wt. Although PP terpolymers are prophetically mentioned, such materials are not disclosed in this case. The cast films made from the PP copolymers showed undesirable high haze. <CIT> describes a process for providing Ziegler-Natta catalyst derived PP terpolymers suitable for blown film comprising at least <NUM> wt. -% of total comonomer with the comonomer units being derived from ethylene and C<NUM> to C<NUM> alpha olefins by way of using <NUM>,<NUM>-diether internal donor catalyst. According to <CIT>, an optimal balance of properties shall be observed when an ethylene content of lower than <NUM> wt. -% is combined with a <NUM>-butene-<NUM> content of higher than <NUM> wt. -%, whereby alternatively when ethylene content is higher than <NUM> wt. -%, <NUM>-butene content should be lower than <NUM> wt. A composition having an ethylene content of <NUM> wt. -% and <NUM> wt. -% <NUM>-butene, i.e. a C<NUM>/C<NUM> (wt/wt) ratio of <NUM> resulted in a SIT as low as <NUM> and <NUM> % haze (<NUM> plaque). However, the films had inacceptable high levels of hexane (C6) extractables of <NUM> wt. -% or above. <CIT> concerns BOPP films, i.e. a totally different type of film made from compositions having varying melting temperatures.

<CIT> discloses a method for providing a terpolymer including units derived from <NUM>-butene using a crosslinked metallocene compound. <CIT> defines ultra-broad ranges as to the structural units derived from <NUM>-butene, namely <NUM> mol% to <NUM> mol%, and structural units derived from ethylene <NUM> mol-% up to <NUM> mol-% with exemplified amounts of <NUM> mol-% ethylene and <NUM> mol-% <NUM>-butene. Although <CIT> has proposed films, films are actually not disclosed in this case.

Thus, there remains a need for a PP terpolymer based blown film having low sealing initiation temperature such as well below <NUM>, low haze such as below <NUM> % and particularly low hexane extractables (FDA) such as below <NUM> wt. Simultaneously, the film should have adequate melt flow rate and high dart drop impact.

These aspects are addressed in the present invention, which is based on the finding that a favourable combination of low hexane extractables, low haze, good dart drop impact and good sealing properties can be provided when the amounts of ethylene units, <NUM>-butene units, their total amount, the <NUM> regioinversions, the molar ratio of units derived from <NUM>-butene versus ethylene and the total amount of defects are carefully tailored.

The present invention insofar provides a blown film made from an ethylenepropylene-<NUM>-butene terpolymer including.

The present invention further provides an ethylene-propylene-<NUM>-butene terpolymer including.

whereby 'defects' denote the sum of units derived from ethylene, units derived from <NUM>-butene and <NUM> regioinversions, all values in mol-%.

Advantageous variants of the blown film and the ethylene-propylene-<NUM>-butene terpolymer are specified in the dependent claims.

In yet a further aspect, the present invention concerns a composition including the ethylene-propylene-<NUM>-butene terpolymer according to the present invention in an amount of at least <NUM> wt.

The regio-defects of propylene polymers can be of three different types, namely <NUM>,<NUM>-erythro (<NUM>,1e), <NUM>,<NUM>-threo (<NUM>,1t) and <NUM>,<NUM> defects. A detailed description of the structure and mechanism of formation of regio defects in polypropylene can be found for example in <NPL>. These defects are measured using <NUM>C-NMR spectroscopy as described in more detail below.

The term "<NUM>,<NUM> regio defects" or "<NUM>,<NUM> regioinversions" as used in the present invention defines the sum of <NUM>,<NUM>-erythro regio-defects and <NUM>,<NUM>-threo regio defects.

The "terpolymer" according to the present invention denotes a polymer made of the monomers ethylene, propylene and <NUM>-butene, whereby these monomers can be found in the polymer chain. The content of units originating from these monomers adds up to <NUM> mol-%. Pseudo-terpolymers being made from mixtures of two copolymers do not subsume under the term "terpolymer" according to the present invention. Pseudo-terpolymers can be recognized by coupled TREF-IR, coupled TREF-NMR or similar methods. As a matter of definition, a terpolymer according to the present invention is not a mixture of two copolymers.

The term "defects" denotes the sum of units derived from ethylene, units derived from <NUM>-butene and <NUM> regioinversions, all values in mol-%.

Where the term "comprising" is used in the present description and claims, it does not exclude other non-specified elements of major or minor functional importance. For the purposes of the present invention, the term "consisting of" is considered to be a preferred embodiment of the term "comprising of". If hereinafter a group is defined to comprise at least a certain number of embodiments, this is also to be understood to disclose a group, which preferably consists only of these embodiments.

Bimodal as to the units derived from <NUM>-butene means that the terpolymer is obtainable in two reactors coupled in series at a split ratio of <NUM>:<NUM> to <NUM>:<NUM>, whereby these reactors are operated such that the intermediate terpolymer being produced in the first reactor differs from the final terpolymer as to the content of units derived from <NUM>-butene by at least <NUM>%, with all contents considered in percent by weight and the first reactor value being used as the reference. For example, <NUM> wt. -% (first reactor) and <NUM> wt. -% (final) fulfills the requirement.

Bimodal as to the molecular weight means that the terpolymer is obtainable in two reactors coupled in series at a split ratio of <NUM>:<NUM> to <NUM>:<NUM>, whereby these reactors are operated such that the intermediate terpolymer being produced in the first reactor differs from the final terpolymer as to the melt flow rate (ISO <NUM>, <NUM> load, <NUM>) by at least <NUM>%, for example <NUM>/<NUM> (first reactor) and <NUM>/<NUM> (final).

The amount of regioinversions is to some extent dependent on the amount of comonomer, i.e. the higher the comonomer content, the lower the content of <NUM> regioinversions. In addition to that, the <NUM> regioinversions can be influenced by choice of the polymerization temperature: a higher polymerization temperature favours a lower content of <NUM> regioinversions.

In another preferred aspect, the terpolymer is bimodal as to the units derived from <NUM>-butene. As outlined above under definitions this means two polymers are present, whereby said polymers differ as to their <NUM>-butene content. It is self-explaining that bimodality as to the <NUM>-butene content may be effected by use of two or more reactors in series or by other measures such as parallel reactor setups and subsequent mixing for example in solution.

In another preferred aspect, the terpolymer is bimodal as to the molecular weight. As outlined in the definition section, this again means presence of two polymers, whereby said polymers differ as to their melt flow rate. The same measures as described above and use of a chain transfer agent, conventionally hydrogen will be suitable for the purpose.

The composition according to the present invention includes the terpolymer in an amount of <NUM> wt. Preferably, the composition according to the present invention consists of the terpolymer as described herein and additives. The additives are preferably selected from the group consisting of slip agents, anti-block agents, UV stabilizers, antistatic agents, acid scavengers, alpha-nucleating agents, antioxidants and mixtures thereof. Such additives are commonly known to a person skilled in the art.

Slip agents migrate to the surface and act as lubricants polymer to polymer and polymer against metal rollers, giving reduced coefficient of friction (CoF) as a result. Examples are fatty acid amids, like erucamide (<NPL>), oleamide (<NPL>), stearamide (<NPL>) or combinations thereof.

Examples of antioxidants which are commonly used in the art, are sterically hindered phenols (such as <NPL>, also sold as Irganox <NUM> FF™ by BASF), phosphorous based antioxidants (such as <NPL>, also sold as Hostanox PAR <NUM> (FF)™ by Clariant, or Irgafos <NUM> (FF)TM by BASF), sulphur based antioxidants (such as <NPL>, sold as Irganox PS-<NUM> FL™ by BASF), nitrogen-based antioxidants (such as <NUM>,<NUM>'- bis(<NUM>,<NUM>'-dimethylbenzyl)diphenylamine), or antioxidant blends.

Acid scavengers are also commonly known in the art. Examples are calcium calcium stearate (<NPL>), zinc stearate (<NPL>), sodium stearate, magnesium and zinc oxide, synthetic hydrotalcite (e.g. SHT,<NPL>), lactates and lactylates.

Common antiblocking agents are natural silica such as diatomaceous earth (such as <NPL> (SuperfFloss™), <NPL> (SuperFloss E™), or <NPL> (Celite <NUM>™)), synthetic silica (such as <NPL>, <NPL>, <NPL>, <NPL>, <NPL>, <NPL>, <NPL>, <NPL>, or <NPL>), silicates (such as aluminium silicate, Kaolin, <NPL>, sodium aluminum silicate <NPL>, calcined kaolin <NPL>, aluminum silicate <NPL>, or calcium silicate <NPL>), synthetic zeolites (such as sodium calcium aluminosilicate hydrate <NPL>, <NPL>, or sodium calcium aluminosilicate, hydrate <NPL>).

Suitable UV-stabilisers are, for example, Bis-(<NUM>,<NUM>,<NUM>,<NUM>-tetramethyl-<NUM>-piperidyl)-sebacate (<NPL>, Tinuvin <NUM>); <NUM>-hydroxy-<NUM>-n-octoxy-benzophenone (<NPL>, Chimassorb <NUM>).

Alpha nucleating agents like sodium benzoate (<NPL>); a mixture of aluminium-hydroxy-bis[<NUM>,<NUM>'-methylene-bis(<NUM>,<NUM>-di-t-butylphenyl)phosphate] and lithium myristate (commercially available as Adekastab NA-<NUM> of Adeka Palmarole, France) or <NUM>,<NUM>:<NUM>,<NUM>-bis(<NUM>,<NUM>- dimethylbenzylidene)sorbitol (<NPL>, commercially available as Millad <NUM> of Milliken, USA) can also be added.

Suitable antistatic agents are, for example, glycerol esters (<NPL>) or ethoxylated amines (<NPL> or<NPL>) or ethoxylated amides (<NPL>).

Most preferably, these additives are present in the range of <NUM> to <NUM> wt. -% based on the total weight of the polymer composition.

In the most general embodiment, the ethylene-propylene-<NUM>-butene terpolymer includes.

In a preferred embodiment the ethylene-propylene-<NUM>-butene terpolymer has.

whereby 'defects' denote the sum of units derived from ethylene, units derived from <NUM>-butene and <NUM> regioinversions, all values in mol-%.

A number of catalysts can be suitable for the present invention.

Generally, the catalyst system used in the present invention may be prepared as described in <CIT>. The catalyst can be used in supported or unsupported form, preferably in supported form. The particulate support material used is preferably an organic or inorganic material, such as silica, alumina or zirconia or a mixed oxide such as silica-alumina, in particular silica, alumina or silica-alumina. The use of a silica support is preferred. The skilled person is aware of the procedures required to support a metallocene catalyst.

Especially preferably, the support is a porous material so that the complex may be loaded into the pores of the support, e.g. using a process analogous to those described in <CIT>), <CIT>) and <CIT>. The average particle size of the silica support can be typically from <NUM> to <NUM>. However, it has turned out that special advantages can be obtained if the support has an average particle size from <NUM> to <NUM>, preferably from <NUM> to <NUM>.

The average pore size of the silica support can be in the range <NUM> to <NUM> and the pore volume from <NUM> to <NUM>/g.

Examples of suitable support materials are, for instance, ES757 produced and marketed by PQ Corporation, Sylopol <NUM> produced and marketed by Grace or SUNSPERA DM-L-<NUM> silica produced by AGC Si-Tech Co. Supports can be optionally calcined prior to the use in catalyst preparation in order to reach optimal silanol group content.

The use of these supports is routine in the art.

Preferred complexes of use in the invention are of formula (II') or (II)
<CHM>.

Further preferred complexes of use in the invention are of formula (III') or (III):
<CHM>.

Further preferred complexes of use in the invention are of formula (IV') or (IV):
<CHM>.

Most preferably, the complex of use in the invention is of formula (V') or (V):
<CHM>.

Particular compounds of the invention include:.

Most preferably rac-anti-Me<NUM>Si(<NUM>-Me-<NUM>-(p-tBuPh)-Ind)(<NUM>-Me-<NUM>-Ph-<NUM>-OMe-<NUM>-tBu-Ind)ZrCl<NUM> is used.

The ligands required to form the complexes and hence catalysts of the invention can be synthesized by any process and the skilled organic chemist would be able to devise various synthetic protocols for the manufacture of the necessary ligand materials. For Example <CIT> discloses the necessary chemistry. Synthetic protocols can also generally be found in <CIT>, <CIT>, <CIT>, <CIT>, <CIT>, <CIT>, <CIT> and <CIT>. The examples section also provides the skilled person with sufficient direction.

To form an active catalytic species it is normally necessary to employ a cocatalyst as is well known in the art. Cocatalysts comprising one or more compounds of Group <NUM> metals, like organoaluminium compounds or boron containing cocatalysts or combinations therefrom used to activate metallocene catalysts are suitable for use in this invention.

In a preferred embodiment of the present invention a cocatalyst system comprising a boron containing cocatalyst, e.g. a borate cocatalyst and an aluminoxane cocatalyst is used.

The single-site polymerization catalyst system used in the invention therefore can comprise (i) a complex as defined above and an aluminoxane cocatalyst.

The aluminoxane cocatalyst can be one of formula (VI):
<CHM>
where n is from <NUM> to <NUM> and R has the meaning below.

Aluminoxanes are formed on partial hydrolysis of organoaluminum compounds, for example those of the formula AIR<NUM>, AIR<NUM>Y and AI<NUM>R<NUM>Y<NUM> where R can be, for example, C<NUM>-C<NUM>-alkyl, preferably C<NUM>-C<NUM>-alkyl, or C<NUM>-C<NUM>-cycloalkyl, C<NUM>-C<NUM>-arylalkyl or -alkylaryl and/or phenyl or naphthyl, and where Y can be hydrogen, halogen, preferably chlorine or bromine, or C<NUM>-C<NUM>-alkoxy, preferably methoxy or ethoxy. The resulting oxygen-containing aluminoxanes are not in general pure compounds but mixtures of oligomers of the formula (VI).

The preferred aluminoxane is methylaluminoxane (MAO).

Since the aluminoxanes used according to the invention as cocatalysts are not, owing to their mode of preparation, pure compounds, the molarity of aluminoxane solutions hereinafter is based on their aluminium content.

According to the present invention, also a boron containing cocatalyst can be used. Boron containing cocatalysts of interest include those of formula (VII).

wherein Y is the same or different and is a hydrogen atom, an alkyl group of from <NUM> to about <NUM> carbon atoms, an aryl group of from <NUM> to about <NUM> carbon atoms, alkylaryl, arylalkyl, haloalkyl or haloaryl each having from <NUM> to <NUM> carbon atoms in the alkyl radical and from <NUM>-<NUM> carbon atoms in the aryl radical or fluorine, chlorine, bromine or iodine. Preferred examples for Y are fluorine, trifluoromethyl, aromatic fluorinated groups such as p-fluorophenyl, <NUM>,<NUM>-difluorophenyl, pentafluorophenyl, <NUM>,<NUM>,<NUM>-trifluorophenyl and <NUM>,<NUM>- di(trifluoromethyl)phenyl. Preferred options are trifluoroborane, tris(<NUM>-fluorophenyl)borane, tris(<NUM>,<NUM>-difluorophenyl)borane, tris(<NUM>-fluoromethylphenyl)borane, tris(<NUM>,<NUM>,<NUM>-trifluorophenyl)borane, tris(pentafluorophenyl)borane, tris(<NUM>,<NUM>-difluorophenyl)borane and/or tris (<NUM>,<NUM>,<NUM>-trifluorophenyl)borane.

Particular preference is given to tris(pentafluorophenyl)borane.

However, it is preferred that as a boron containing cocatalyst borates are used, i.e. compounds containing a borate.

These compounds generally contain an anion of formula:.

where Z is an optionally substituted phenyl derivative, said substituent being a halo-C<NUM>-<NUM>-alkyl or halo group. Preferred options are fluoro or trifluoromethyl. Most preferably, the phenyl group is perfluorinated.

Such ionic cocatalysts preferably contain a weakly-coordinating anion such as tetrakis(pentafluorophenyl)borate or tetrakis(<NUM>,<NUM>-di(trifluoromethyl)phenyl)borate. Suitable counterions are protonated amine or aniline derivatives such as methylammonium, anilinium, dimethylammonium, diethylammonium, N-methylanilinium, diphenylammonium, N,N-dimethylanilinium, trimethylammonium, triethylammonium, tri-n-butylammonium, methyldiphenylammonium, pyridinium, p-bromo-N,N- dimethylanilinium or p-nitro-N,N-dimethylanilinium.

Preferred ionic compounds which can be used according to the present invention include:.

According to the present invention, it is especially preferred to use an aluminoxane cocatalyst, like MAO, together with a boron containing cocatalyst, like borate cocatalyst.

Suitable amounts of co-catalyst will be well known to the skilled person.

Preferably, the amount of cocatalyst is chosen to reach molar ratios defined below. The molar ratio of feed amounts of boron (B) to the metal ion (M) (preferably zirconium) of the metallocene boron/M may be in the range <NUM>:<NUM> to <NUM>:<NUM> mol/mol, preferably <NUM>:<NUM> to <NUM>:<NUM>, especially <NUM>:<NUM> to <NUM>:<NUM> mol/mol.

Even more preferably, the molar ratio of feed amounts of boron (B) to metal ion (M) (preferably zirconium) of the metallocene boron/M is from <NUM>:<NUM> to <NUM>:<NUM>.

The molar ratio of Al from the aluminoxane to the metal ion (M) (preferably zirconium) of the metallocene Al/M may be in the range <NUM>:<NUM> to <NUM>:<NUM> mol/mol, preferably <NUM>:<NUM> to <NUM>:<NUM>, and more preferably <NUM>:<NUM> to <NUM>:<NUM> mol/mol.

Other suitable catalysts systems are described in <CIT>. In the broadest aspect, the catalyst complex fulfills the following structure. <CHM>
whereby.

As specific methallocene catalyst complexes the following three embodiments abbreviated MC1, MC2 and MC3 may be mentioned.

rac-anti-dimethylsilanediyl[<NUM>-methyl-<NUM>,<NUM>-bis-(<NUM><'>-tert-butylphenyl)-<NUM> ,<NUM>,<NUM>,<NUM>-tetrahydro-s- indacen-<NUM> -yl][<NUM>-methyl-<NUM>-(<NUM>',<NUM>'-dimethyl-phenyl)-<NUM>-methoxy-<NUM>-tert-butylinden-<NUM> -yl] zirconium dichloride     (MC-<NUM> ).

rac-anti-dimethylsilanediyl[<NUM>-methyl-<NUM>,<NUM>-bis-(<NUM>',<NUM>'-dimethylphenyl)-<NUM> ,<NUM>,<NUM>,<NUM>-tetrahydro-s indacen-<NUM> -yl] [<NUM>-methyl-<NUM>-(<NUM>',<NUM>'-dimethylphenyl)-<NUM>-methoxy-<NUM>-tert-butylinden-<NUM> -yl] zirconium dichloride     (MC-<NUM>).

rac-anti-dimethylsilanediyl[<NUM>-methyl-<NUM>,<NUM>-bis-(<NUM>',<NUM>'-dimethylphenyl)-<NUM> ,<NUM>,<NUM>,<NUM>-tetrahydro-s- indacen-<NUM>-yl][<NUM>-methyl-<NUM>-(<NUM>',<NUM>'-ditert-butyl-phenyl)-<NUM>-methoxy-<NUM>-tert-butylinden-<NUM>-yl] zirconium dichloride     (MC-<NUM>).

including also their corresponding zirconium dimethyl analogues.

The polymer composition according to the present invention may be compounded and pelletized using any of the variety of compounding and blending machines and methods well known and commonly used in the resin compounding art. For blending the individual components of the instant composition a conventional compounding or blending apparatus, for example a Banbury mixer, a <NUM>-roll rubber mill, Buss-co-kneader or a twin-screw extruder may be used. The compositions recovered from the extruder/mixer are usually in the form of pellets. These pellets are then further processed and formed into a blown film according to present invention. The compositions according to the present invention preferably include the terpolymer as described herein in an amount of at least <NUM> wt. More preferably, the compositions according to the present invention consist of the terpolymer as described herein in an amount of at least <NUM> wt. -% and additives. Preferred additives for this purpose have been described further above.

The blown film according to the present invention is a made from the ethylenepropylene-<NUM>-butene terpolymer as described above. All preferred aspects also hold for the blown film.

As briefly outline above, the present invention concerns a blown film made from an ethylene-propylene-<NUM>-butene terpolymer including.

Such film can be made on blown film lines known in the art, like air-cooled or water-cooled blown film lines, including multilayer co-extrusion lines.

"Blown film made from the ethylene-propylene-<NUM>-butene terpolymer" according to the present invention means that at least one layer comprises the ethylenepropylene-<NUM>-butene terpolymer, preferably consists of the ethylene-propylene-<NUM>-butene terpolymer composition according to the present invention.

It is advantageous to produce the blown films by using a single screw extruder with a barrel diameter of about <NUM> and a round-section die of about <NUM> with about <NUM> die gap in combination with a monolip cooling ring and internal bubble cooling (IBC). Melt temperature can be selected from <NUM> to <NUM>° C. In the die; the temperature of the cooling air of <NUM>° to <NUM>. As a typical blow up ratio (BUR) <NUM>:<NUM> to <NUM>:<NUM> can be used. The film thickness can be adjusted easily through the ratio between extruder output, take-off speed and BUR.

It is possible to use a Collin blown film line with a screw diameter of about <NUM> millimeters (mm), LID of about <NUM>, a die diameter of about <NUM>, a die gap of about <NUM> and a duo-lip cooling ring. A production temperature of about <NUM> with about <NUM> blow-up-ratio can be recommended.

The blown film according to the present invention is preferably made from an ethylene-propylene-<NUM>-butene terpolymer having units derived from ethylene in an amount of <NUM> to <NUM> mol-% with respect the total terpolymer.

In another preferred aspect, the blown film according to the present invention is preferably made from an ethylene-propylene-<NUM>-butene terpolymer having units derived from <NUM>-butene in an amount of <NUM> to <NUM> mol-% with respect the total terpolymer.

It is also preferred that the blown film according to the present invention is made from an ethylene-propylene-<NUM>-butene terpolymer having a total amount of units derived from ethylene and <NUM>-butene of <NUM> to <NUM> mol-%.

In a further preferred aspect, the blown film according to the present invention is made from an ethylene-propylene-<NUM>-butene, wherein the molar ratio of units derived from <NUM>-butene versus units derived from ethylene is within the range of of <NUM> to <NUM>.

It is also preferred that the blown film according to the present invention is made from an ethylene-propylene-<NUM>-butene terpolymer having <NUM> regioinversions in an amount of <NUM> to <NUM> mol-% as determined by <NUM>C-NMR analysis (as described in the experimental part).

In a particularly preferred embodiment, the blown film according to the present invention is made from an the ethylene-propylene-<NUM>-butene terpolymer including.

The blown film according to the present invention is preferably made from an ethylene-propylene-<NUM>-butene terpolymer having a flexural modulus of <NUM> to <NUM> MPa measured according to ISO <NUM>, preferably <NUM> to <NUM> MPa.

In another aspec, the blown film according to the present invention is preferably made from an ethylene-propylene-<NUM>-butene terpolymer which is bimodal as to the butene content and/or is bimodal as to the molecular weight.

The advantageous nature of the blown film according to the present invention can be understood when considering the optomechanical ability (OMA) with respect to machine direction (MD) usually determined on <NUM> micrometer thick test film, with OMA (for <NUM> micrometer thick film) being <MAT>.

The optomechanical ability (OMA) of the inventive film is at least <NUM>, preferably <NUM>, most preferably <NUM>.

It shall be mentioned that film thickness is not limited to <NUM> micrometer. A <NUM> micrometer thick film is merely used as a test specimen for easier comparison. Usually and preferably the blown films according the present invention are made from an ethylene-propylene-<NUM>-butene terpolymer having a hexane solubility (FDA) of <NUM> wt. -% or less.

Quantitative <NUM>C{<NUM>H} NMR spectra recorded in the molten-state using a Bruker Avance III <NUM> NMR spectrometer operating at <NUM> and <NUM> for <NUM>H and <NUM>C respectively. All spectra were recorded using a <NUM>C optimised <NUM> magic-angle spinning (MAS) probehead at <NUM> using nitrogen gas for all pneumatics. Approximately <NUM> of material was packed into a <NUM> outer diameter zirconia MAS rotor and spun at <NUM>. This setup was chosen primarily for the high sensitivity needed for rapid identification and accurate quantification {klimke06, parkinson07, castignolles09}. Standard single-pulse excitation was employed utilising the NOE at short recycle delays of <NUM> {pollard04, klimke06} and the RS-HEPT decoupling scheme {fillip05,griffin07}. A total of <NUM> (<NUM>) transients were acquired per spectra.

Quantitative <NUM>C{<NUM>H} NMR spectra were processed, integrated and relevant quantitative properties determined from the integrals. All chemical shifts are internally referenced to the methyl isotactic pentad (mmmm) at <NUM> ppm. Characteristic signals corresponding to the incorporation of <NUM>-butene were observed {brandolini01} and the comonomer content quantified.

The amount of isolated <NUM>-butene incorporated in PBP sequences was quantified using the integral of the αB2 sites at <NUM> ppm accounting for the number of reporting sites per comonomer: <MAT>.

The amount of consecutively incorporated <NUM>-butene in PBBP sequences was quantified using the integral of the ααB2B2 site at <NUM> ppm accounting for the number of reporting sites per comonomer: <MAT>.

In presence of BB the value of B must be corrected for the influence of the αB2 sites resulting from BB: <MAT>.

The total <NUM>-butene content was calculated based on the sum of isolated and consecutively incorporated <NUM>-butene: <MAT>.

Characteristic signals corresponding to the incorporation of ethylene were observed {brandolini01} and the comonomer content quantified.

The amount of isolated ethylene incorporated in PEP sequences was quantified using the integral of the Sββ sites at <NUM> ppm accounting for the number of reporting sites per comonomer:<MAT>.

If characteristic signals corresponding to consecutive incorporation of ethylene in PEE sequence was observed the Sβδ site at <NUM> ppm was used for quantification:<MAT>EE = ISβδ.

Characteristic signals corresponding to regio defects were observed {resconi00}. The presence of isolated <NUM>,<NUM>-erythro regio defects was indicated by the presence of the two methyl sites at <NUM> and <NUM> ppm, by the methylene site at <NUM> ppm and confirmed by other characteristic sites. The presence of <NUM>,<NUM> regio defect adjacent an ethylene unit was indicated by the two inequivalent Sαβ signals at <NUM> ppm and <NUM> ppm respectively and the Tγγ at <NUM> ppm.

The amount of isolated <NUM>,<NUM>-erythro regio defects (P21e isolated) was quantified using the integral of the methylene site at <NUM> ppm (Ie9):<MAT>.

If present the amount of <NUM>,<NUM> regio defect adjacent to ethylene (PE21) was quantified using the methine site at <NUM> ppm (ITγγ):<MAT>.

The total ethylene content was then calculated based on the sum of ethylene from isolated, consecutively incorporated and adjacent to <NUM>,<NUM> regio defects: <MAT>.

The amount of propene was quantified based on the Sαα methylene sites at <NUM> ppm including all additional propene units not covered by Sαα e.g. the factor <NUM>*P21e isolated accounts for the three missing propene units from isolated <NUM>,<NUM>-erythro regio defects: <MAT>.

The total mole fraction of <NUM>-butene and ethylene in the polymer was then calculated as: <MAT> <MAT>.

The mole percent comonomer incorporation was calculated from the mole fractions: <MAT> <MAT>.

The weight percent comonomer incorporation was calculated from the mole fractions: <MAT> <MAT>.

The mole percent of isolated <NUM>,<NUM>-erythro regio defects was quantified with respect to all propene: <MAT>.

The mole percent of <NUM>,<NUM> regio defects adjacent to ethylene was quantified with respect to all propene: <MAT>.

The total amount of <NUM>,<NUM> defects was quantified as following: <MAT>.

Characteristic signals corresponding to other types of regio defects (<NUM>,<NUM>-threo, <NUM>,<NUM> insertion) were not observed {resconi00}.

c) DSC analysis, melting temperature (Tm) and crystallization temperature (Tc):
was measured with a TA Instrument Q2000 differential scanning calorimetry (DSC) on <NUM> to <NUM> samples. DSC was run according to ISO <NUM> / part <NUM> / method C2 in a heat / cool / heat cycle with a scan rate of <NUM>/min in the temperature range of - <NUM> to +<NUM>. Crystallization temperature (Tc) and crystallization enthalpy (Hc) were determined from the cooling step, while melting temperature (Tm) and melting enthalpy (Hm) were determined from the second heating step.

All film properties (except hexane solubles) were determined on monolayer blown films of <NUM> thickness produced on a Collin <NUM> lab scale blown film line.

This line has a screw diameter of <NUM> millimeters (mm), LID of <NUM>, a die diameter of <NUM>, a die gap of <NUM> and a duo-lip cooling ring. The film samples were produced at <NUM> with an average thickness of <NUM>, with a <NUM>:<NUM> blow-up-ratio and an output rate of about <NUM> kilograms per hour (kg/h).

e) Haze
was determined according to ASTM D1003-<NUM> on the blown test films of <NUM> micrometer thickness.

The hot-tack force was determined according to ASTM F1921-<NUM> - Method B on a J&B Hot- Tack Tester on a <NUM> pm thickness film produced on a monolayer blown film line. All film test specimens were prepared in standard atmospheres for conditioning and testing at <NUM> (plus minus <NUM> C) and <NUM> percent (plus minus <NUM> %) relative humidity.

The minimum conditioning time of test specimen in standard atmosphere before start testing is at least <NUM>. The minimum storage time between extrusion of film sample and start testing is at least <NUM>.

The hot tack measurement determines the strength of heat seals formed in the films, immediately after the seal has been made and before it cools to ambient temperature. The hot- tack measurement was performed under the following conditions.

The hot-tack force was measured as a function of temperature within the temperature range and with temperature increments as indicated above. The number of test specimens was at least <NUM> specimens per temperature. The output of this method is a hot tack curve, a force vs. temperature curve.

The hot tack force (HTF) was evaluated from the curve as the highest force (maximum peak value) with failure mode "peel".

Sealing initiation temperature (SIT); sealing end temperature (SET), sealing range: The method determines the sealing temperature range (sealing range) of polypropylene films, in particular blown films or cast films according to ASTM F1921 - <NUM>. Seal pressure, cool time and peel speed were modified as stated below.

The sealing temperature range is the temperature range, in which the films can be sealed according to conditions given below.

The lower limit (heat sealing initiation temperature (SIT)) is the sealing temperature at which a sealing strength of > <NUM> N is achieved. The upper limit (sealing end temperature (SET)) is reached, when the films stick to the sealing device.

The sealing range was determined on a J&B Universal Sealing Machine Type <NUM> with a blown film of <NUM>µηη thickness with the following further parameters:.

Specimen is sealed A to A at each sealbar temperature and seal strength (force) was determined at each step.

The temperature was determined at which the seal strength reaches <NUM> N.

The hexane extractable fraction was determined according to the FDA method (federal registration, title <NUM>, Chapter <NUM>, part <NUM>, section <NUM>, s.

The measurements were carried out according to FDA section <NUM> with <NUM> of a polymer film of <NUM> thickness being added to <NUM> hexane at <NUM> for <NUM> hours while stirring with a reflux cooler. After <NUM> hours, the mixture is immediately filtered on a filter paper. The precipitate is collected in an aluminium recipient and the residual hexane is evaporated on a steam bath under N<NUM> flow. The amount of hexane solubles is determined by the formula ((wt. sample + wt. crucible) - (wt crucible)) / (wt. sample) × <NUM>%.

The film used in the test had been produced on a Collin cast film lab line, with melt temperature of <NUM>, output rate of <NUM>/h, chill roll temperature <NUM>.

Tensile Modulus in machine and transverse direction were determined according to ISO <NUM>-<NUM> at <NUM> on blown films of <NUM> thickness produced as described above. Testing was performed at a cross-head speed of <NUM>/min.

Dart-drop was measured using ASTM D1709, method A (Alternative Testing Technique) from the film samples. A dart with a <NUM> diameter hemispherical head was dropped from a height of <NUM> onto a film clamped over a hole. Successive sets of twenty specimens were tested. One weight was used for each set and the weight is increased (or decreased) from set to set by uniform increments. The weight resulting in failure of <NUM> % of the specimens was calculated and reported.

Optomechanical ability (OMA) is understood as the ratio of mechanical (especially impact and flexural) behaviour, to optical performance, namely haze, wherein the mechanical properties are targeted to be as high as possible and the optical performance is desired to be as low as possible.

The optomechanical ability is determined according the formula given below: <MAT>.

with Tensile Modulus being determined in both machine direction (MD) and transverse direction (TD) [MPa], DDI(g) and haze measured as described above.

The flexural modulus was determined in <NUM>-point-bending at <NUM> according to ISO <NUM> on 80x10x4 mm<NUM> test bars injection moulded in line with EN ISO <NUM>-<NUM>.

The xylene soluble (XS) fraction as defined and described in the present invention was determined in line with ISO <NUM> as follows: <NUM> of the polymer were dissolved in <NUM> p-xylene at <NUM> under agitation. After <NUM> minutes, the solution was allowed to cool for <NUM> minutes at ambient temperature and then allowed to settle for <NUM> minutes at <NUM> +/- <NUM>. The solution was filtered with filter paper into two <NUM> flasks. The solution from the first <NUM> vessel was evaporated in nitrogen flow and the residue dried under vacuum at <NUM> until constant weight is reached. The xylene soluble fraction (percent) can then be determined as follows: <MAT> mo = initial polymer amount (g); m = weight of residue (g); V<NUM> = initial volume (ml); v = volume of analysed sample (ml).

The metallocene (MC1) (rac-anti-dimethylsilandiyl(<NUM>-methyl-<NUM>-phenyl-<NUM>-methoxy-<NUM>-tert-butyl-indenyl)(<NUM>-methyl-<NUM>-(<NUM>-tert-butylphenyl)indenyl)zirconium dichloride) has been synthesized as described in <CIT>.

A steel reactor equipped with a mechanical stirrer and a filter net was flushed with nitrogen and the reactor temperature was set to <NUM>. Next silica grade DM-L-<NUM> from AGC Si-Tech Co, pre-calcined at <NUM> (<NUM>) was added from a feeding drum followed by careful pressuring and depressurising with nitrogen using manual valves. Then toluene (<NUM>) was added. The mixture was stirred for <NUM>. Next <NUM> wt% solution of MAO in toluene (<NUM>) from Lanxess was added via feed line on the top of the reactor within <NUM>. The reaction mixture was then heated up to <NUM> and stirred at <NUM> for additional two hours. The slurry was allowed to settle and the mother liquor was filtered off. The MAO treated support was washed twice with toluene (<NUM>) at <NUM>, following by settling and filtration. The reactor was cooled off to <NUM> and the solid was washed with heptane (<NUM>). Finally MAO treated SiO2 was dried at <NUM>° under nitrogen flow for <NUM> hours and then for <NUM> hours under vacuum (-<NUM> barg) with stirring. MAO treated support was collected as a free-flowing white powder found to contain <NUM>% Al by weight.

<NUM> wt% MAO in toluene (<NUM>) was added into a steel nitrogen blanked reactor via a burette at <NUM>. Toluene (<NUM>) was then added under stirring. Metallocene MC1 (<NUM>) was added from a metal cylinder followed by flushing with <NUM> toluene. The mixture was stirred for <NUM> minutes at <NUM>. Trityl tetrakis(pentafluorophenyl) borate (<NUM>) was then added from a metal cylinder followed by a flush with <NUM> of toluene. The mixture was stirred for <NUM> at room temperature. The resulting solution was added to a stirred cake of MAO-silica support prepared as described above over <NUM> hour. The cake was allowed to stay for <NUM> hours, followed by drying under N2 flow at <NUM> for <NUM> and additionally for <NUM> under vacuum (-<NUM> barg) under stirring. Dried catalyst was sampled in the form of pink free flowing powder containing <NUM> wt% Al and <NUM>.

The catalyst used was Anti-dimethylsilanediyl[<NUM>-methyl-<NUM>,<NUM>-di(<NUM>,<NUM>-dimethylphenyl)-<NUM>,<NUM>,<NUM>,<NUM>-tetrahydro-s-indacen-<NUM>-yl][<NUM>-methyl-<NUM>-(<NUM>,<NUM>-dimethylphenyl)-<NUM>-methoxy-<NUM>-tert-butylinden-<NUM>-yl] zirconium dichloride.

The metallocene complex has been produced as described in <CIT> for MC-<NUM>.

A steel reactor equipped with a mechanical stirrer and a filter net was flushed with nitrogen and the reactor temperature was set to <NUM>. Next silica grade DM-L-<NUM> from AGC Si-Tech Co, pre-calcined at <NUM> (<NUM>) was added from a feeding drum followed by careful pressurising and depressurising with nitrogen using manual valves. Then toluene (<NUM>) was added. The mixture was stirred for <NUM>. Next <NUM> wt. -% solution of MAO in toluene (<NUM>) from Lanxess was added via feed line on the top of the reactor within <NUM>. The reaction mixture was then heated up to <NUM> and stirred at <NUM> for additional two hours. The slurry was allowed to settle and the mother liquor was filtered off. The catalyst was washed twice with toluene (<NUM>) at <NUM>, following by settling and filtration. The reactor was cooled off to <NUM> and the solid was washed with heptane (<NUM>). Finally MAO treated SiO2 was dried at <NUM>° under nitrogen flow for <NUM> hours and then for <NUM> hours under vacuum (-<NUM> barg) with stirring. MAO treated support was collected as a free-flowing white powder found to contain <NUM>% Al by weight.

-% MAO in toluene (<NUM>) was added into a steel nitrogen blanked reactor via a burette at <NUM>. Toluene (<NUM>) was then added under stirring. The catalyst as cited above (<NUM>) was added from a metal cylinder followed by flushing with <NUM> toluene. The mixture was stirred for <NUM> minutes at <NUM>. Trityl tetrakis(pentafluorophenyl) borate (<NUM>) was then added from a metal cylinder followed by a flush with <NUM> of toluene. The mixture was stirred for <NUM> at room temperature. The resulting solution was added to a stirred cake of MAO-silica support prepared as described above over <NUM> hour. The cake was allowed to stay for <NUM> hours, followed by drying under N2 flow at <NUM> for <NUM> and additionally for <NUM> under vacuum (-<NUM> barg) under stirring. Dried catalyst was sampled in the form of pink free flowing powder containing <NUM>% Al and <NUM>% Zr.

First, <NUM> mol of MgCl<NUM> × <NUM> EtOH was suspended under inert conditions in <NUM> of decane in a reactor at atmospheric pressure. The solution was cooled to the temperature of-<NUM> and <NUM> of cold TiCl<NUM> was added while maintaining the temperature at said level. Then, the temperature of the slurry was increased slowly to <NUM>. At this temperature, <NUM> mol of dioctylphthalate (DOP) was added to the slurry. After the addition of the phthalate, the temperature was raised to <NUM> during <NUM> minutes and the slurry was allowed to stand for <NUM> minutes. Then, another <NUM> of TiCl<NUM> was added and the temperature was kept at <NUM> for <NUM> minutes. After this, the catalyst was filtered from the liquid and washed six times with <NUM> heptane at <NUM>. Then, the solid catalyst component was filtered and dried. Catalyst and its preparation concept is described in general e.g. in patent publications <CIT>, <CIT> and <CIT>. The catalyst was used with triethyl-aluminium (TEAL) as co-catalyst and dicyclo pentyl dimethoxy silane (D-donor) as donor.

Terpolymers IE1 - IE4 were produced in a Borstar pilot plant comprising a prepolymerization reactor, one loop reactor and a gas phase reactor coupled in series. The polymerization conditions as well as the results of polymer characterization are indicated in Table <NUM>. IE1 - IE <NUM> were made with catalyst system number one (#<NUM>) as described above, and IE4 was made with the catalyst system number two (#<NUM>).

All examples were compounded in a co-rotating twin-screw extruder Coperion ZSK <NUM> at <NUM> with with <NUM> wt. -% antiblocking agent (synthetic silica; <NPL>); <NUM> wt. -% antioxidant (Irgafos 168FF, <NPL>, BASF AG); <NUM> wt. -% of a sterical hindered phenol (Irganox 1010FF, <NPL>, BASF AG); <NUM> wt. -% of DHT-4A (<NPL>).

It can be seen that carefully tailoring the amount of units derived from ethylene, the total amount of units derived from ethylene and butene, as well as the ratio of units from butene versus ethylene together with control of <NUM> regioinversions results in relatively low melting temperature for a given amount of total defects. Simultaneously the hexane solubility is also very low. CE2 was excluded from the further evaluation due to inacceptable high hexane solubility (FDA).

The characteristics of the blown films made from the terpolymers are provided below in Table <NUM>.

Claim 1:
A blown film made from an ethylene-propylene-<NUM>-butene terpolymer including
a) units derived from ethylene in an amount of <NUM> to <NUM> mol-% with respect the total terpolymer; and
b) units derived from propylene in an amount of <NUM> to <NUM> mol-% with respect the total terpolymer; and
c) units derived from <NUM>-butene in an amount of <NUM> to <NUM> mol-% with respect the total terpolymer,
d) whereby the units derived from ethylene, propylene and <NUM>-butene add up to <NUM> mol-% and
e) a total amount of units derived from ethylene and <NUM>-butene of <NUM> to <NUM> mol-%, and
f) a molar ratio of units derived from <NUM>-butene versus units derived from ethylene of <NUM> to <NUM>, wherein the amount of units derived from ethylene, propylene and <NUM>-butene is measured as described in the description; and
g) <NUM> regioinversions in an amount of <NUM> to <NUM> mol-% as determined by <NUM>C-NMR analysis (as described in the experimental part); and
h) a melt flow rate MFR<NUM> (<NUM> / <NUM>) measured according to ISO <NUM> in the range from <NUM> to <NUM>/<NUM>, and
i) a melting temperature Tm measured by differential scanning calorimetry (DSC) following the equation <MAT>
whereby 'defects' denote the sum of units derived from ethylene, units derived from <NUM>-butene and <NUM> regioinversions, all values in mol-%, and
whereby the blown film has a sealing initiation temperature (SIT) (as determined by a method described in the experimental part) below <NUM>.