Patent Description:
Injection molded parts such as food packaging and plastic cups place specific requirements on the polymeric materials employed to produce these articles.

Polypropylene-based polymers have many characteristics, which make them suitable for applications such as molded articles, but also pipes, fittings and foams.

Frequently, polypropylene products of high stiffness are based on high molecular weight materials, which are often nucleated by adding nucleating agents, i.e. crystallization starts at a higher temperature and the crystallization speed is high.

It has now been found that by fine tuning a polypropylene copolymer composition containing propylene homopolymer and propylene ethylene homopolymer it is possible to obtain a copolymer having good mechanical properties and good haze.

Thus, the present disclosure provides a polypropylene composition comprising: A) From <NUM> wt% to <NUM> wt%; of a propylene homopolymer having a fraction insoluble in xylene at <NUM> greater than <NUM> wt%; and a melt flow rate, MFR, measured according to ISO <NUM>-<NUM> at <NUM> with a load of <NUM> comprised between <NUM>/<NUM> and <NUM>/<NUM>; B) From <NUM> wt% to <NUM> wt%; of a propylene ethylene copolymer having an ethylene derived units content ranging from <NUM> wt% to <NUM> wt%, measured by <NUM>C NMR;.

Thus, the present disclosure provides a polypropylene composition comprising:.

For the present disclosure, the term "copolymer" is referred to polymers containing only two kinds of comonomers, such as propylene and ethylene.

The polypropylene composition of the present disclosure is not subjected to a chemical or physical visbreaking, i.e. the MFR is obtained with the polymerization process.

Preferably in the polypropylene composition the intrinsic viscosity measured on the fraction soluble in xylene at <NUM> ranges from <NUM> to <NUM> dl/g; preferably from <NUM> to <NUM> dl/g; more preferably from <NUM> to <NUM> dl/g.

The polypropylene composition according to the present disclosure is preferably characterized by having one or more of the following properties:.

These features, due to the particular polymerization process used and the particular Ziegler Natta catalyst used in the polymerization, make the polypropylene composition according to the present disclosure particularly fit for the production of molded articles, in particular injection molded articles or thermoformed articles. The polypropylene composition of the present disclosure is obtained with a polymerization process in two or more stages in which component A) is obtained in the first stages and then component B) is obtained in the second stages in the presence of component A). each stage can be in gas-phase, operating in one or more fluidized or mechanically agitated bed reactors, slurry phase using as diluent an inert hydrocarbon solvent, or bulk polymerization using the liquid monomer (for example propylene) as a reaction medium. Preferably component B) is polymerized in a gas phase process in the presence of component A).

The polymerization is generally carried out at temperature of from <NUM> to <NUM>, preferably of from <NUM> to <NUM>. When the polymerization is carried out in gas-phase the operating pressure is generally between <NUM> and <NUM> MPa, preferably between <NUM> and <NUM> MPa. In the bulk polymerization the operating pressure is generally between <NUM> and <NUM> MPa, preferably between <NUM> and <NUM> MPa. Hydrogen is typically used as a molecular weight regulator.

The polypropylene composition herein disclosed is prepared by a process comprising homopolymerizing propylene in a first stage and then propylene with ethylene in a second stage, both stages being conducted in the presence of a catalyst system comprising the product obtained by contacting (a) a solid catalyst component having average particle size ranging from <NUM> to <NUM> comprising a magnesium halide, a titanium compound having at least a Ti-halogen bond and at least one electron donor compounds such as succinates and the other being selected from <NUM>,<NUM> diethers, (b) an aluminum hydrocarbyl compound and optionally (c) an external electron donor compound.

Preferably, the succinate present in the solid catalyst component (a) is selected from succinates of formula (I) below
<CHM>
in which the radicals R<NUM> and R<NUM>, equal to, or different from, each other are a C<NUM>-C<NUM> linear or branched alkyl, alkenyl, cycloalkyl, aryl, arylalkyl or alkylaryl group, optionally containing heteroatoms; and the radicals R<NUM> and R<NUM> equal to, or different from, each other, are C<NUM>-C<NUM> alkyl, C3-C20 cycloalkyl, C5-C20 aryl, arylalkyl or alkylaryl group with the proviso that at least one of them is a branched alkyl; said compounds being, with respect to the two asymmetric carbon atoms identified in the structure of formula (I), stereoisomers of the type (S,R) or (R,S).

R<NUM> and R<NUM> are preferably C<NUM>-C<NUM> alkyl, cycloalkyl, aryl, arylalkyl and alkylaryl groups. Particularly preferred are the compounds in which R<NUM> and R<NUM> are selected from primary alkyls and in particular branched primary alkyls. Examples of suitable R<NUM> and R<NUM> groups are methyl, ethyl, n-propyl, n-butyl, isobutyl, neopentyl, <NUM>-ethylhexyl. Particularly preferred are ethyl, isobutyl, and neopentyl.

Particularly preferred are the compounds in which the R<NUM> and/or R<NUM> radicals are secondary alkyls like isopropyl, sec-butyl, <NUM>-pentyl, <NUM>-pentyl or cycloakyls like cyclohexyl, cyclopentyl, cyclohexylmethyl.

Examples of the above-mentioned compounds are the (S,R) (S,R) forms pure or in mixture, optionally in racemic form, of diethyl <NUM>,<NUM>-bis(trimethylsilyl)succinate, diethyl <NUM>,<NUM>-bis(<NUM>-ethylbutyl)succinate, diethyl <NUM>,<NUM>-dibenzylsuccinate, diethyl <NUM>,<NUM>-diisopropylsuccinate, diisobutyl <NUM>,<NUM>-diisopropylsuccinate, diethyl <NUM>,<NUM>-bis(cyclohexylmethyl)succinate, diethyl <NUM>,<NUM>-diisobutylsuccinate, diethyl <NUM>,<NUM>-dineopentylsuccinate, diethyl <NUM>,<NUM>-dicyclopentylsuccinate, diethyl <NUM>,<NUM>-dicyclohexylsuccinate.

Among the <NUM>,<NUM>-diethers mentioned above, particularly preferred are the compounds of formula (II)
<CHM>
where RI and RII are the same or different and are hydrogen or linear or branched C<NUM>-C<NUM> hydrocarbon groups which can also form one or more cyclic structures; RIII groups, equal or different from each other, are hydrogen or C<NUM>-C<NUM> hydrocarbon groups; RIV groups equal or different from each other, have the same meaning of RIII except that they cannot be hydrogen; each of RI to RIV groups can contain heteroatoms selected from halogens, N, O, S and Si.

Preferably, RIV is a <NUM>-<NUM> carbon atom alkyl radical and more particularly a methyl while the RIII radicals are preferably hydrogen. Moreover, when RI is methyl, ethyl, propyl, or isopropyl, RII can be ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, isopentyl, <NUM>-ethylhexyl, cyclopentyl, cyclohexyl, methylcyclohexyl, phenyl or benzyl; when RI is hydrogen, RII can be ethyl, butyl, sec-butyl, tert-butyl, <NUM>-ethylhexyl, cyclohexylethyl, diphenylmethyl, p-chlorophenyl, <NUM>-naphthyl, <NUM>-decahydronaphthyl; RI and RII can also be the same and can be ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, neopentyl, phenyl, benzyl, cyclohexyl, cyclopentyl.

Specific examples of ethers that can be advantageously used include: <NUM>-(<NUM>-ethylhexyl)<NUM>,<NUM>-dimethoxypropane, <NUM>-isopropyl-<NUM>,<NUM>-dimethoxypropane, <NUM>-butyl-<NUM>,<NUM>-dimethoxypropane, <NUM>-sec-butyl-<NUM>,<NUM>-dimethoxypropane, <NUM>-cyclohexyl-<NUM>,<NUM>-dimethoxypropane, <NUM>-phenyl-<NUM>,<NUM>-dimethoxypropane, <NUM>-tert-butyl-<NUM>,<NUM>-dimethoxypropane, <NUM>-cumyl-<NUM>,<NUM>-dimethoxypropane, <NUM>-(<NUM>-phenylethyl)-<NUM>,<NUM>-dimethoxypropane, <NUM>-(<NUM>-cyclohexylethyl)-<NUM>,<NUM>-dimethoxypropane, <NUM>-(p-chlorophenyl)-<NUM>,<NUM>-dimethoxypropane, <NUM>-(diphenylmethyl)-<NUM>,<NUM>-dimethoxypropane, <NUM>(<NUM>-naphthyl)-<NUM>,<NUM>-dimethoxypropane, <NUM>(p-fluorophenyl)-<NUM>,<NUM>-dimethoxypropane, <NUM>(<NUM>-decahydronaphthyl)-<NUM>,<NUM>-dimethoxypropane, <NUM>(p-tert-butylphenyl)-<NUM>,<NUM>-dimethoxypropane, <NUM>,<NUM>-dicyclohexyl-<NUM>,<NUM>-dimethoxypropane, <NUM>,<NUM>-diethyl-<NUM>,<NUM>-dimethoxypropane, <NUM>,<NUM>-dipropyl-<NUM>,<NUM>-dimethoxypropane, <NUM>,<NUM>-dibutyl-<NUM>,<NUM>-dimethoxypropane, <NUM>,<NUM>-diethyl-<NUM>,<NUM>-diethoxypropane, <NUM>,<NUM>-dicyclopentyl-<NUM>,<NUM>-dimethoxypropane, <NUM>,<NUM>-dipropyl-<NUM>,<NUM>-diethoxypropane, <NUM>,<NUM>-dibutyl-<NUM>,<NUM>-diethoxypropane, <NUM>-methyl-<NUM>-ethyl-<NUM>,<NUM>-dimethoxypropane, <NUM>-methyl-<NUM>-propyl-<NUM>,<NUM>-dimethoxypropane, <NUM>-methyl-<NUM>-benzyl-<NUM>,<NUM>-dimethoxypropane, <NUM>-methyl-<NUM>-phenyl-<NUM>,<NUM>-dimethoxypropane, <NUM>-methyl-<NUM>-cyclohexyl-<NUM>,<NUM>-dimethoxypropane, <NUM>-methyl-<NUM>-methylcyclohexyl-<NUM>,<NUM>-dimethoxypropane, <NUM>,<NUM>-bis(p-chlorophenyl)-<NUM>,<NUM>-dimethoxypropane, <NUM>,<NUM>-bis(<NUM>-phenylethyl)-<NUM>,<NUM>-dimethoxypropane, <NUM>,<NUM>-bis(<NUM>-cyclohexylethyl)-<NUM>,<NUM>-dimethoxypropane, <NUM>-methyl-<NUM>-isobutyl-<NUM>,<NUM>-dimethoxypropane, <NUM>-methyl-<NUM>-(<NUM>-ethylhexyl)-<NUM>,<NUM>-dimethoxypropane, <NUM>,<NUM>-bis(<NUM>-ethylhexyl)-<NUM>,<NUM>-dimethoxypropane,<NUM>,<NUM>-bis(p-methylphenyl)-<NUM>,<NUM>-dimethoxypropane, <NUM>-methyl-<NUM>-isopropyl-<NUM>,<NUM>-dimethoxypropane, <NUM>,<NUM>-diisobutyl-<NUM>,<NUM>-dimethoxypropane, <NUM>,<NUM>-diphenyl-<NUM>,<NUM>-dimethoxypropane, <NUM>,<NUM>-dibenzyl-<NUM>,<NUM>-dimethoxypropane, <NUM>-isopropyl-<NUM>-cyclopentyl-<NUM>,<NUM>-dimethoxypropane, <NUM>,<NUM>-bis(cyclohexylmethyl)-<NUM>,<NUM>-dimethoxypropane, <NUM>,<NUM>-diisobutyl-<NUM>,<NUM>-diethoxypropane, <NUM>,<NUM>-diisobutyl-<NUM>,<NUM>-dibutoxypropane, <NUM>-isobutyl-<NUM>-isopropyl-<NUM>,<NUM>-dimetoxypropane, <NUM>,<NUM>-di-sec-butyl-<NUM>,<NUM>-dimetoxypropane, <NUM>,<NUM>-di-tert-butyl-<NUM>,<NUM>-dimethoxypropane, <NUM>,<NUM>-dineopentyl-<NUM>,<NUM>-dimethoxypropane, <NUM>-iso-propyl-<NUM>-isopentyl-<NUM>,<NUM>-dimethoxypropane, <NUM>-phenyl-<NUM>-benzyl-<NUM>,<NUM>-dimetoxypropane, <NUM>-cyclohexyl-<NUM>-cyclohexylmethyl-<NUM>,<NUM>-dimethoxypropane.

Furthermore, particularly preferred are the <NUM>,<NUM>-diethers of formula (III)
<CHM>
where the radicals RIV have the same meaning explained above and the radicals RIII and RV radicals, equal or different to each other, are selected from the group consisting of hydrogen; halogens, preferably Cl and F; C<NUM>-C<NUM> alkyl radicals, linear or branched; C<NUM>-C<NUM> cycloalkyl, C<NUM>-C<NUM> aryl, C<NUM>-C<NUM> alkaryl and C<NUM>-C<NUM> aralkyl radicals and two or more of the RV radicals can be bonded to each other to form condensed cyclic structures, saturated or unsaturated, optionally substituted with RVI radicals selected from the group consisting of halogens, preferably Cl and F; C<NUM>-C<NUM> alkyl radicals, linear or branched; C<NUM>-C<NUM> cycloalkyl, C<NUM>-C<NUM> aryl, C<NUM>-C<NUM> alkaryl and C<NUM>-C<NUM> aralkyl radicals; said radicals RV and RVI optionally containing one or more heteroatoms as substitutes for carbon or hydrogen atoms, or both.

Preferably, in the <NUM>,<NUM>-diethers of formulae (I) and (II) all the RIII radicals are hydrogen, and all the RIV radicals are methyl. Moreover, are particularly preferred the <NUM>,<NUM>-diethers of formula (II) in which two or more of the RV radicals are bonded to each other to form one or more condensed cyclic structures, preferably benzenic, optionally substituted by RVI radicals. Specially preferred are the compounds of formula (IV):
<CHM>
where the RVI radicals equal or different are hydrogen; halogens, preferably Cl and F; C<NUM>-C<NUM> alkyl radicals, linear or branched; C<NUM>-C<NUM> cycloalkyl, C<NUM>-C<NUM> aryl, C<NUM>-C<NUM> alkylaryl and C<NUM>-C<NUM> aralkyl radicals, optionally containing one or more heteroatoms selected from the group consisting of N, <NUM>, S, P, Si and halogens, in particular Cl and F, as substitutes for carbon or hydrogen atoms, or both; the radicals RIII and RIV are as defined above for formula (III).

Specific examples of compounds comprised in formulae (III) and (IV) are:.

As explained above, the catalyst component (a) comprises, in addition to the above electron donors, a titanium compound having at least a Ti-halogen bond and an Mg halide. The magnesium halide is preferably MgCl<NUM> in active form which is widely known from the patent literature as a support for Ziegler-Natta catalysts. <CIT> and <CIT> were the first to describe the use of these compounds in Ziegler-Natta catalysis. It is known from these patents that the magnesium dihalides in active form used as support or co-support in components of catalysts for the polymerization of olefins are characterized by X-ray spectra in which the most intense diffraction line that appears in the spectrum of the non-active halide is diminished in intensity and is replaced by a halo whose maximum intensity is displaced towards lower angles relative to that of the more intense line.

The preferred titanium compounds used in the catalyst component of the present invention are TiCl<NUM> and TiCls; furthermore, also Ti-haloalcoholates of formula Ti(OR)n-yXy can be used, where n is the valence of titanium, y is a number between <NUM> and n-<NUM> X is halogen and R is a hydrocarbon radical having from <NUM> to <NUM> carbon atoms.

Preferably, the catalyst component (a) has an average particle size ranging from <NUM> to <NUM> and more preferably from <NUM> to <NUM>. As explained the succinate is present in an amount ranging from <NUM> to <NUM>% by weight with respect to the total amount of donors. Preferably it ranges from <NUM> to <NUM>%by weight and more preferably from <NUM> to <NUM>%by weight. The <NUM>,<NUM>-diether preferably constitutes the remaining amount.

The aluminum hydrocarbyl compound (b) is preferably an aluminum hydrocarbyl compound in which the hydrocarbyl is selected from C<NUM>-C<NUM> branched aliphatic or aromatic radicals; preferably it is chosen among those in which the branched radical is an aliphatic one and more preferably from branched trialkyl aluminum compounds selected from triisopropylaluminum, tri-iso-butylaluminum, tri-iso-hexylaluminum, tri-iso-octylaluminum. It is also possible to use mixtures of branched trialkylaluminum's with alkylaluminum halides, alkylaluminum hydrides or alkylaluminum sesquichlorides such as AlEt<NUM>Cl and Al<NUM>Et<NUM>Cl<NUM>.

Preferred external electron-donor compounds include silicon compounds, ethers, esters such as ethyl <NUM>-ethoxybenzoate, amines, heterocyclic compounds and particularly <NUM>,<NUM>,<NUM>,<NUM>-tetramethyl piperidine, ketones and the <NUM>,<NUM>-diethers. Another class of preferred external donor compounds is that of silicon compounds of formula Ra<NUM>Rb<NUM>Si(OR<NUM>)c, where a and b are integer from <NUM> to <NUM>, c is an integer from <NUM> to <NUM> and the sum (a+b+c) is <NUM>; R<NUM>, R<NUM>, and R<NUM>, are alkyl, cycloalkyl or aryl radicals with <NUM>-<NUM> carbon atoms optionally containing heteroatoms. Particularly preferred are methylcyclohexyldimethoxysilane, diphenyldimethoxysilane, methyl-t-butyldimethoxysilane, dicyclopentyldimethoxysilane, <NUM>-ethylpiperidinyl-<NUM>-t-butyldimethoxysilane and <NUM>,<NUM>,<NUM>,trifluoropropyl-<NUM>-ethylpiperidinyl-dimethoxysilane and <NUM>,<NUM>,<NUM>,trifluoropropyl-metil-dimethoxysilane. The external electron donor compound is used in such an amount to give a molar ratio between the organo-aluminum compound and said electron donor compound of from <NUM> to <NUM>, preferably from <NUM> to <NUM> and more preferably from <NUM> to <NUM>.

In step (i) the catalyst forming components are contacted with a liquid inert hydrocarbon solvent such as, e.g., propane, n-hexane or n-heptane, at a temperature below about <NUM> and preferably from about <NUM> to <NUM> for a time period of from about six seconds to <NUM> minutes.

The above catalyst components (a), (b) and optionally (c) are fed to a pre-contacting vessel, in amounts such that the weight ratio (b)/(a) is in the range of <NUM>-<NUM> and if the compound (c) is present, the weight ratio (b)/(c) is weight ratio corresponding to the molar ratio as defined above. Preferably, the said components are pre-contacted at a temperature of from <NUM> to <NUM> for <NUM>-<NUM> minutes. The precontact vessel can be either a stirred tank or a loop reactor.

Thus high transparency and good mechanical properties can be obtained.

The polypropylene composition of the present disclosure can contain the additives that are commonly used in the art such as anti-oxidants, process stabilizers, slip agents, antistatic agents, antiblock agents, antifog agents and nucleating agents.

The following examples are given to illustrate, not to limit, the present disclosure:.

Xylene Solubles at <NUM> have been determined according to ISO <NUM><NUM>; with solution volume of <NUM>, precipitation at <NUM> for <NUM> minutes, <NUM> of which with the solution in agitation (magnetic stirrer), and drying at <NUM>.

Measured according to ISO <NUM>-<NUM> at <NUM> with a load of <NUM>, unless otherwise specified.

The sample is dissolved in tetrahydronaphthalene at <NUM> and then poured into a capillary viscometer. The viscometer tube (Ubbelohde type) is surrounded by a cylindrical glass jacket; this setup allows for temperature control with a circulating thermostatic liquid. The downward passage of the meniscus is timed by a photoelectric device.

The passage of the meniscus in front of the upper lamp starts the counter, which has a quartz crystal oscillator. The meniscus stops the counter as it passes the lower lamp and the efflux time is registered: this is converted into a value of intrinsic viscosity through Huggins' equation (<NPL>) provided that the flow time of the pure solvent is known at the same experimental conditions (same viscometer and same temperature). One single polymer solution is used to determine [η].

Injection molded speciments prepared according to ISO <NUM>-<NUM>, and ISO <NUM> have been used. The haze value is measured using a Gardner photometric unit connected to a Hazemeter type UX-<NUM> or an equivalent instrument having G. <NUM> light source with filter "C". Reference samples of known haze are used for calibrating the instrument according to.

Determined according to IS0 <NUM> and supplemental condition according to ISO <NUM>-<NUM> with specimen injection moulded.

<NUM>C NMR spectra were acquired on a Bruker AV-<NUM> spectrometer equipped with cryoprobe, operating at <NUM> in the Fourier transform mode at <NUM>.

The peak of the Sββ carbon (nomenclature according to "<NPL>) was used as an internal reference at <NUM> ppm. The samples were dissolved in <NUM>,<NUM>,<NUM>,<NUM>-tetrachloroethane-d2 at <NUM> with a <NUM> % wt/v concentration. Each spectrum was acquired with a <NUM>° pulse, and <NUM> seconds of delay between pulses and CPD to remove <NUM>H-<NUM>C coupling. <NUM> transients were stored in <NUM> data points using a spectral window of <NUM>.

The assignments of the spectra, the evaluation of triad distribution and the composition were made according to Kakugo ("<NPL>) using the following equations: <MAT> <MAT> <MAT>.

The molar percentage of ethylene content was evaluated using the following equation:.

E% mol = <NUM> * [PEP+PEE+EEE]The weight percentage of ethylene content was evaluated using the following equation: <MAT> <MAT> where P% mol is the molar percentage of propylene content, while MWE and MWP are the molecular weights of ethylene and propylene, respectively.

The product of reactivity ratio rlr2 was calculated according to Carman (<NPL>) as: <MAT>.

The tacticity of Propylene sequences was calculated as mm content from the ratio of the PPP mmTββ (<NUM>-<NUM> ppm) and the whole Tββ (<NUM>-<NUM> ppm).

Charpy impact test has been measured according to ISO <NUM>-1eA, e ISO <NUM>-<NUM>.

Tensile Modulus has been measured according to ISO <NUM>-<NUM>, and ISO <NUM>-<NUM> on injection molded sample.

Determined according to FDA <NUM>, <NUM> by suspending in an excess of hexane a specimen of the composition. The film is prepared by extrusion. The suspension is put in an autoclave at <NUM> for <NUM> hours then the hexane is remove by evaporation and the dried residue is weighted.

The temperature has been measured according to ISO <NUM>-<NUM>, at scanning rate of 20C/min both in cooling and heating, on a sample of weight between <NUM> and <NUM>. , under inert N2 flow. Instrument calibration made with Indium.

The determination of Mg and Ti content in the solid catalyst component has been carried out via inductively coupled plasma emission spectroscopy on "I. P Spectrometer ARL Accuris".

The sample was prepared by analytically weighting, in a "Fluxy" platinum crucible", <NUM>÷<NUM> grams of catalyst and <NUM> grams of lithium metaborate/tetraborate <NUM>/<NUM> mixture. After addition of some drops of KI solution, the crucible is inserted in a special apparatus "Claisse Fluxy" for the complete burning. The residue is collected with a <NUM>% v/v HNO<NUM> solution and then analyzed via ICP at the following wavelengths: Magnesium, <NUM>; Titanium, <NUM>.

The determination of Bi content in the solid catalyst component has been carried out via inductively coupled plasma emission spectroscopy on "I. P Spectrometer ARL Accuris".

The sample was prepared by analytically weighting in a <NUM><NUM> volumetric flask <NUM>÷<NUM> grams of catalyst. After slow addition of both ca. <NUM> milliliters of <NUM>% v/v HNO<NUM> solution and ca. <NUM><NUM> of distilled water, the sample undergoes a digestion for <NUM>÷<NUM> hours. Then the volumetric flask is diluted to the mark with deionized water. The resulting solution is directly analyzed via ICP at the following wavelength: Bismuth, <NUM>.

The determination of the content of internal donor in the solid catalytic compound was done through gas chromatography. The solid component was dissolved in acetone, an internal standard was added, and a sample of the organic phase was analyzed in a gas chromatograph, to determine the amount of donor present at the starting catalyst compound.

Into a <NUM> four-necked round flask, purged with nitrogen, <NUM> of TiCl<NUM> were introduced at <NUM>. While stirring, <NUM> of microspheroidal MgCl<NUM>·<NUM>. 5C<NUM>H<NUM>OH having average particle size of <NUM> (prepared by thermally dealcoholating a starting adduct obtained according to the procedure of example <NUM> of <CIT>) an amount of diethyl <NUM>,<NUM>-diisopropylsuccinate in racemic form such as to have a Mg/succinate molar ratio of <NUM> was added. The temperature was raised to <NUM> and kept at this value for <NUM>. After siphoning, fresh TiCl<NUM> and an amount of <NUM>,<NUM>-bis(methoxymethyl)fluorine (bMMF) such as to have a Mg/(bMMF) molar ratio of <NUM> were added. Then the temperature was raised to <NUM> and kept to this value for for <NUM>. After siphoning, the treatment with TiCl<NUM> was repeated at <NUM> for <NUM> the solid was washed six times with anhydrous hexane (<NUM> x <NUM>) at <NUM> and finally dried.

Before introducing it into the polymerization reactors, the solid catalyst component described above have been contacted with triethyl aluminum (TEAL), no external doors has been used. Then the resulting mixture is subjected to prepolymerization by maintaining it in suspension in liquid propylene at <NUM> for about <NUM> minutes before introducing it into the polymerization reactor.

The polymerization of component A) is carried out in continuous in a series of two reactors equipped with devices to transfer the product from the first reactor to the second one. The polymerization was carried out in gas-phase polymerization reactor comprising two interconnected polymerization zones, a riser and a downcomer, no "barrier stream" has been used.

The polymer (A) coming from the first reactor is discharged in a continuous flow and, after having been purged of unreacted monomers, is introduced, in a continuous flow, into the second stirred bed gas phase reactor. In the second reactor a copolymer of ethylene (B) is produced.

Quantities of monomers and hydrogen fed to the polymerization reactor are reported in Table <NUM>.

The polymer of examples <NUM> and <NUM> and comparative example <NUM> have been characterized as reported in table <NUM>.

Claim 1:
A polypropylene composition comprising:
A) From <NUM> wt% to <NUM> wt%; of a propylene homopolymer having a fraction insoluble in xylene at <NUM> greater than <NUM> wt%; and a melt flow rate, MFR, measured according to ISO <NUM>-<NUM> at <NUM> with a load of <NUM> comprised between <NUM>/<NUM> and <NUM>/<NUM>;
B) From <NUM> wt% to <NUM> wt%; of a propylene ethylene copolymer having an ethylene derived units content ranging from <NUM> wt% to <NUM> wt% , measured by <NUM>C NMR;
said polypropylene composition having:
i) xylene soluble fraction at <NUM> ranging from <NUM> wt% to <NUM> wt%;
ii) the ethylene derived units content on the fraction insoluble in xylene at <NUM> ranging from <NUM> wt% to <NUM> wt% measured by <NUM>C NMR;;
iii) the ethylene derived units content on the fraction soluble in xylene at <NUM> ranging from <NUM> wt% to <NUM> wt%, measured by <NUM>C NMR;
(iv) melt flow rate, MFR, measured according to ISO <NUM>-<NUM> at <NUM> with a load of <NUM>, comprised between <NUM>/<NUM> and <NUM>/<NUM>;
the sum of the amounts of A) and B) being <NUM> wt% .