MXPA97008282A - Procedure for the preparation of random propylene compound and products obtained from me - Google Patents

Abstract

The present invention relates to the preparation of random copolymers of propylene with C2-C10 alpha-olefins, carried out in the presence of a catalyst comprising: a solid component comprising a titanium compound supported on MbCl2 in active form and a electron donor compound, an alkyl-Al compound, and an electron-donor compound selected from the group of 1,3-dieters, the copolymers obtained using said method show, for an equivalent content of alpha-olefin, a lower content of fractions soluble in xylene wcompared to the copolymers obtained with the prior art catalysts

Description

PROCEDURE FOR LR PREPARATION OF RANDOM PROPYLENE COPOLYMERS AND PRODUCTS OBTAINED FL FROM THEMSELVES DESCRIPTIVE MEMORY The present invention relates to a process for the preparation of random copolymers of propylene with ethylene? another or-olefma. The invention relates to random flakes of propylene linteros which have excellent properties in terms of low contents of soluble fractions in full. In particular, the present invention relates to a process for the preparation of random propylene copolymers, carried out in the presence of a catalyst system comprising: (A) a solid component comprising a Ti compound supported on MgCl 2 and a electron donor compound, (B) an alkylaluminum compound and (C) an external electron donor compound selected from the group of 1,3-d? ee-teres. Commonly known as random propylene limes are copolymers containing from 85 to 99% by weight of propylene and from 1 to 15% by weight of ethylene and / or other -oletma, in which the cornone is randomly distributed in the polypropylene chain. Compared with propylene copolymer furnaces, said copolymers have a molecular structure that is altered by the presence of the coronorne, leading to a degree of substantially substantial internal stanality therein. As a result, random copolymers have a sealing temperature and a modulus of elasticity that are lower than those of the full-pipe homopolymers, these characteristics make these copolymers particularly useful for the preparation These are films in which improved impact strength and low sealing initiation temperatures are required (II). However, the introduction of the ornonoinei on the polypropylene chain does not lead to an increase said polymer fraction being soluble in xylene at 25 ° C, said soluble polymer being composed mainly of low molecular weight chains and containing comonomer percentages that are greater than the average comonomer content calculated on the basis of the polymer The amount of soluble fraction generally increases when the content of comonomer in the copolymer is increased and, beyond defined limits, affects the use of the limblet in certain sectors, for example in the preparation of films for wrapping food, unless that a phase of expensive elimination of the soluble fraction is used, therefore, the presence of relevant quantities of said tramines decreases. uye the flowability of the polymer granules, thus making difficult such operations as the discharge and transfer of the polymer, and creating problems of handling the polymerization plant, even, the presence of such soluble fractions in Significant amounts carry over time to f-enomenos of deterioration of the optical properties due to the migration of these fractions to the surface (formation of surface layer). Therefore, it is necessary to have available a catalyst that has a tendency to produce low levels of soluble fractions and which, at the same time, is capable of distributing to the coronomer sati factorially in the polypropylene chain to obtain the desired effect (decrease of the module and / or decrease of the sealing temperature) with low contents of cornone. Moreover, said catalyst must possess an activity in such a way as to produce a copolymer having very low levels of catalytic residues (Ti <15 ppm), thus making an additional removal step unnecessary. It is known from European patent EP-B-318, 049 that the stereo and quasi stereo zirconocenes used as catalysts in the polymerization of ole fine are capable of giving, in high yields, random propylene copolymers having a ba or xylene soluble fraction content. However, said copolymers have a very limited molecular weight distribution that makes them difficult to process using standard techniques and process apparatus. European patent application EP-A-341,724 describes a process for the preparation of random propylene copolymers carried out in the gas phase, in the presence of a catalytic system consisting of: a solid catalyst component (i) consisting of magnesium, titanium, halogen and the electon donor compound that belongs to the group of policarboxylic acid esters; a a qui lalurnimo (11); an external electron donor compound (m) having at least one Si-Ü-C bond. However, the amount of xylene-soluble fractions in the copolymer is still high (19% by weight of soluble fractions with 5.7% by weight of ethylene). A process that is capable of providing, in high yields, random polypropylene copolymers having a particularly low content of xylene-soluble fractions has now surprisingly been discovered. Therefore, it is an object of the present invention a process for the preparation of propylene copolymers containing up to 15% by weight of ethene and / or of an or-olefin CH2 = CHRi, wherein R1 is a hydrocarbon radical which has from 2 to 10 carbon atoms, said process being carried out in the presence of a catalyst comprising: (A) a solid component comprising a Ti compound containing at least one Ti-halogen bond supported on magnesium chloride in active form and an electron donor compound; (B) an alkyl-Al compound; and (or an electron donor compound selected from the group consisting of 1,3-d eethers of the formula (1): in which R, Rl, Rt? t R? r? , iv and RV J JS, which are identical or different, are linear or branched alkyl hydrogen derivatives, cycloalkyl radicals, aryl radicals, alkyl radicals or aplaxyl radicals having 1-18 carbon atoms. -bono, with the proviso that R and Ri are not simultaneously hydrogen; RVI and RVii, which are identical or different, are straight or branched alkyl radicals, cycloalkyl radicals, aryl radicals, l-arylaryl radicals or anialkyl radicals having 1-18 carbon atoms; at least two of said radicals from R to RVH can be linked together to form one or more cyclic structures .. The α-olefin CH2 = CHRi is preferably butene or hexene .. Magnesium chloride in active form present in the component solid (A) is widely known in the art and is characterized by an X-ray spectrum in which the intense diffraction line which appears in the non-activated chloride sample shows a decreased intensity and in said spectrum a halide appears whose maximum intensity is shifted to lower angles with respect to that of the intense line. The preferred Ti compounds are: T1CI and T1CI3; however, the TiO2 haioaLcox of the formula l "? (OR) n-yXy 'where n is the valence of the titanium and y is a number between 1 and n, can also be used.The internal electron donor compound can be selected from esters, ethers, amines and ketones, it is preferably selected from esters of alkyls, cycloalkyls or aplics of rnononocarboxylic acids, for example, tonic acid or polycarboxylic acids, for example phthalic or maleic acid, said alkyl, cycloalkyl or aryl groups have from L to 18 carbon atoms Examples of said electron-donor compounds are methyl benzoate, ethyl benzoate and d-sobutyl phthalate.The solid component (A) can be prepared conveniently by the reaction between a titanium compound of the formula Ti (OR) np> XpP where n is the valence of titanium and rn is a number between 1 and n, and the adduct f1gCl2 -pROH, where p is a number of 0.1 to 4 and R is a hydrocarbon radical that t It has 1-18 carbon atoms. The adduct can be conveniently prepared in spherical form by mixing the alcohol and the magnesium chloride, under stirring conditions, in an inert hydrocarbon which is immiscible with the adduct and which operates at the melting point of the adduct (100 -130 ° C. ). The emulsion obtained in this way is subsequently cooled rapidly, causing the adduct to solidify into spherical particles. Examples of the preparation of adducts in ferric form are described in the patent of E.U.A. No. 4,399,054. The adduct thus obtained generally contains from 2 to 4 moles of alcohol per mole of HgCl 2 - The adduct can be directly reacted with the titanium compound or can be previously subjected to a controlled thermal dealcoholization (between 60 and 60 minutes). 130"C) to reduce the alcohol content to less than 2 mols, preferably from 0.1 to 1 mols. The reaction between the adduct and the titanium compound (preferably T1Cl4) can be carried out by suspending the adduct of the alcohol. MgCl2 in cold T1CI4 (generally 0 ° C), the mixture is then brought to a temperature of 8Q-135 ° C and maintained at this temperature for 0.5-2 hours The internal electron donor compound can be added to the T1CI4 in molar ratios -It is between 1: 6 and 1:16 in relation to MgCl2.T1Cl4 treatment can be repeated one or more times Examples of catalysts prepared according to this procedure are described in EP-A-395, 083. The catalysts obtained two according to the described process have a surface area (measured by the BET method) generally between 20 and 400 rn2 / g and preferably between 50 and 350 m2 / g, and a porosity (measured by the BET method) generally greater than 0.2 cmS g, preferably between 0.2 and 0.5 crn3 / g.

The use of the catalyst component described above allows the preparation of smells on the spherical urine that make the hair step + unnecessary. The alkyl-Al (B) compound is used in molar ratios of Al / Ti of at about 10 and 1000, preferably between LO and LOO. The compound (B) is preferably selected from alkyl-Al compounds such as rimeti lo-Al, tet lio-Al, Russianbuti Lo-Al, tri-n-buti o-Al and t pn-octi lo- Al . r < -? rnb? en can usars »Mixtures of t-alkyl-A compounds with alkyl-Al halides or alkylo-Al sesquihalides such as AlMe2Cl, A1E + -2C1 and l2 t3Cl3, as well as compounds containing two or more Al structures fixed to each other by means of 0 or N atoms or SO3 or SO4 groups. The electron donor compound (C) is preferably selected from 1,3-d-esters of the formula (I) wherein at least one of R and R1 is a secondary or tertiary hydrocarbon radical of the alkyl, cycloalkyl or aromatic. Preferably, at least one of R and Rl is selected from isopropyl, sec-butyl, tert-butyl, cyclobutyl, cyclopentyl and phenyl which are optionally substituted. RVi and R II o, Qn preferably methyl, while ii, Ri 11,? V and RV c and preferably hydrogen. Representative examples of compounds of formula (I) that can be used in the process of the invention are: 2-rnet? L-2-? Soprop? L-1, 3-d? Rnetox? Ropano, 2, 2-d ?? sobut? Ll, 3-d? Rnetox? -propane, 2, 2 -di - phenol-1, 3-di methoxypropane, 2, 2-di-benzyl-1-1, -dirnetoxy propane, 2,2-b? s (c? clohex? lrnet? l) -i, 3-d? rnet.ox.? propane, 2, 2-? sobut? ll, 3 - di but oxy propane,, -dn sobutyl-1, 3-diethoxypropane, 2-? sopent? -2-? so? ro? , 3 ~ d? -? Netox? Pr'opano, 2, 2, 4 -trunetil-l, 3-d? Rnetox? Pentane, 1, 1 '-bi sünetox uneti) -cyclohexane, (±) -2, 2 '-bisirnetoxirnetii) norbor-nano, 2-? soprop? l ~ 2- (3, 7-d? rnet? loct? l) - 1, -d? rnetox? pro? an, 2, 2-d ?? I used 1-1.3-dirnetox i-propane, 2-? so? rop? l-2-cyclohexylrneti 1 -1, 3-d? rnetox? -propane,, 2-diisopentyl-1, J-dimethoxypropane, - iso? rop? l-2-c? clohex? l-1, 3-d? rnetox? pro? ano, 2-? sopro ?? 1-2-c? Cl pent? L-l, 3-dirnetox ipropane, 2, 2-d? C? Clo? Ent? L-l, 3-d? Methox? P? Opane, 2-heptyl-2-? ent? ll, 3-methoxypropane, 2,2-d? c? clohex? ll, 3-di ethoxy propane, 2,2-d? -prop? ll, 3 -dirnetoxy propane, 2-? Sopro? L ~ 2-? Sobut? Ll, 3-d? Methox? Propane. Among these, the preferred compounds are 2, 2-d? Phen? -1, 3-d? Rnetoxyl? A, 2,2-bis- (cycloexilnetyl) -i, 3-d? Methox? Propane, 2, 2-d? So-pro? Ll, 3-dimethoxypropane, 2-? soprop? l-2-c? clohex? lrnet? i ~ i, 3-d ?? netox? -propane, 2, 2-d? c? clopent? i-i, 3-d? -rnetox? ropano and 2-? soprop? l-2-? sopent 11-1,3- dirnetox i p ropano. The electron donor compound (C) is used in amounts that give a molar ratio between the compound of the qui-Al and said compound (C) generally between 0.5 and 50, preferably between 1 and 30 and most preferably between 1 and 10. The polymerization process can be carried out in accordance with known methodologies, for example by the suspension technique using one or more inert droplet-bonding solvents as diluents or in liquid monomer, which is using propylene. as the liquid reaction medium. It is also possible to carry out the process in the gas phase, working in one or more fiuidi ated beds or mechanically agitated reactors. The polymerization is generally carried out at temperatures of between 20 and 12 ° C, preferably between 40 and 80 ° C. When a process is carried out in the gas phase, the operating pressure is generally between 10 and 10 MPa, preferably between 1 and 2 MPa. In the case of liquid polymerization, however, the operating pressure is between 1 and 5 MPa, preferably between 1.5 and 3 MPa. Hydrogen or other compounds having the same function as molecular weight regulators can be used. A further aspect of the present invention relates to specific randomized propylene-ethylene copolymers which are obtainable using the process of the present invention. Said copolymer have the following characteristics: - 0.1% and 15% by weight ethereal content.; - molecular weight distribution (MWD), expressed in terms of pM / nM, of more than 2.5; catalytic residue content, expressed in terms of pprn of Ti, of less than 15; - Natural logarithm of the content by weight of fraction soluble in xylene and percentage by weight of etiienic units, calculated on the basis of the total polymer, so that the point defined by these values falls below the straight line given by the equation: where: Xs -% by weight of the fraction soluble in xylene at 25 ° C; C2 -% by weight of etiienic units in the 10 eopolymer; a = 1.73; b = Ü.29. The ethylene content of the copolymers is preferably between 0.5 and 10%, most preferably between 1 and 6%. The copolymers of the invention preferably have L5 a DPM of more than 3, and most preferably more than 3.5. The amount of catalytic residues is preferably less than LO and most preferably less than 2 pprn Ti. Particularly preferred are copolymers in which the natural logarithm of the weight content of f-action soluble in xfill and the percentage by weight of ethiic units define points located below the straight line given by the equation mentioned above in which a - 1.68, and most preferably below the straight line given above in which a-1.55. It has also been noted that the ethylene / propylene copolymers of the present invention have a favorable balance between the content of the soluble fraction in full x and the melting point in relation to a given content of zero. In particular, they are also characterized because they have a natural logarithm of content of fractionation soluble in xylene / melting point that corresponds to the value of the content of the coinonomer, so that the point defined by said values falls below the straight line given by the equation: Ln (Xs / T? nJ Ln (c) * «IO2 where: Xs =% by weight of the fraction soluble in x filled at 25 ° C, 2 =% by weight of units of ethylene in the copolymer, c = 0.009, d = 0.32, Pre emin e, c is 0.007 and most preferably 0.005 Another particular aspect of the present invention relates to specific random propylene-butene copolymers which are obtainable using the process of the present invention These copolymers have the following characteristics: - butene content between 0.1 and 15% by weight, - molecular weight distribution (MWD), expressed in terms of pM / nM, of of 2.5; content of catalytic residues, expressed in 1 J terms of pprn of Ti, less than 15, - natural logarithm of the content by weight of fraction soluble in xylene and percentage by weight of units of butene, calculated on the basis of the total polymer, so that the point defined by these values falls below the straight line given by the equation: ln (Xs) - ln (a) + C «where: Xs =% by weight of the fraction soluble in x filled at 25 ° C; C "=% by weight of butene units in the copolymer; e = 1.57; f • = 0.08. The butene content of the copolymers is preferably between 0.5 and 10%, most preferably between 1 and 6%. The copolymers of the invention preferably have a DPM of more than, and most preferably of more than 3.5. The amount of catalytic residues is preferably less than and most preferably less than 2 ppin of Ti. Particularly preferred are copolymers in which the natural logarithm of the percentage by weight of soluble fraction in full and the percentage by weight of units of butene, define points located below the straight line corresponding to the equation given above in which = 1.52 and most preferably below the straight line given above in which e = 1.47.

As mentioned, random propylene copolymers having the characteristics described above are particularly suitable for use in the preparation of low temperature sealing films. When used in these applications, said copolymers show surprisingly a SIT / soluble hexane-fraction balance compared to conventional copolymers. The following examples are given by way of non-limiting illustration of the invention.

Characterization - melt index (MIL): ASTM D-1238, condition "L". Content of cornonornero: Percentage by weight of the co-operative determined by IR spectrum. - Intrinsic viscosity Cn3: ASTM 2857-70. - Differential Scanning Calorimetry (DSC): Measurements made in a DSC-7 instrument of Per ín Elmer Co. Ltd., according to the following procedure. Approximately 10 rng of the sample are heated to 180 ° C at a scanning speed of 20 ° C / nm; The sample is maintained at 180 ° C for 5 minutes and then cooled to a scanning speed of 20 ° C / nm. A second scrutiny is carried out later in the same way as for the first. The values reported are those obtained in the second scrutiny. - Determination of average PPM: This is determined by GPC using a Uaters 150 machine equipped with a TSK column set (type GM-HT? I) working at 135 ° C with 1, 2-d? Chlorobenzene as solvent (stabilized with 0.1% by volume of p -cresol of 2,6-d? -butyl (BHT)). The rnonodisperse polystyrene fractions are used as a meter. The universal calibration for PP copolymers was carried out using a linear combination of the Mark -1-louw? Ni * constants for PP and PE. - Solubility in xylene 2.5 g of copolymer and 250 crn3 of o-xylene are placed in a glass flask equipped with a condenser and a magnetic stirrer. The temperature is increased to the boiling point of the solvent for 30 minutes. The clear solution formed in this manner is allowed to reflux with stirring for an additional 30 minutes. The closed medium is then placed in an ice-water bath for 30 minutes and then in a thermostatic water bath set at 25 ° C for 30 minutes. The solid formed is then filtered on filter paper at a high filtration rate. 100 crn3 of the liquid obtained from the filtration are emptied into a pre-weighed aluminum container, which is placed on a hot plate to evaporate the liquid under a stream of nitrogen. The container is then placed in an oven at 80 ° C and kept under vacuum until a constant weight is obtained. - Catalytic residues (ppm of Ti): The titanium pprn in the polymer are calculated based on the performance of L6 polymerization and the percentage by weight of Ti present in the solid component. - Sealing temperature (WíT): This is defined as the temperature required to seal two films and thus obtain a breaking load by sealing rnas of 0.250 kg / crn. It is determined on a 20 μm thick film obtained according to the following procedure: the polymer, to which stabilizers have been added, is a noise in a film of 50 microns thick. The film thus obtained is coupled with a polypropylene oven film of 500 micrometers thickness and is subjected to biaxial orientation in the directions of the machine and transverse to obtain a total thickness of less than 20 microns. - Determination of the solubility in hexane: FDA No. 1771520 EXAMPLES Preparation of MgCl2 / alcohol adduct The spherical adduct of MgC12 / alcohol was prepared according to the method described in Example 2 of USP 4,399,054, working at 3000 rpm instead of 10,000 rpm. The adduct is then partially dealcoholated by heating it in a stream of nitrogen at temperatures increasing from 30 to 180 ° C.

Preparation of the catalytic component A This was prepared according to the general procedure described in EP 395,083, producing a solid having the following composition: Mg, 16.% by weight Cl, 56.2% by weight Ti, 2.35% by weight D1J- P, 7.2% in e ^ o EXAMPLE 1 0. 0255 g of a catalytic component (A) prepared according to the procedure described above was contacted with 0.457 g of tpetilalumi nio (TEAL) and 0.320 g of 2, 2-d? C? C Lopent? L-1, - d? methoxy? ane in 5 crn3 of hexane in a round glass flask of 50 crn3. The mixture was introduced in a 4.25 liter steel autoclave, previously purged, by successively washing with hexane at 80 ° C for 1 hour and then with propylene gas at 80 ° C for 1 hour. 1450 g of liquid propylene, 9.7 g of ethylene and 3700 cm3 of H2 were then introduced at 25 ° C. The temperature was brought to 70 ° C and the mixture was polintepzo for 90 minutes, adding 18 g of ethylene and 3700 crn3 of H2. We obtained 863 g of random copolymer of? Ol? (Pro? Leno-et? Leno) that had the characteristics reported in table 1.

L8 EXAMPLE 2 The procedure was carried out using the same catalyst - as described in Example 1, using 0.0411 g b of the solid catalyst component with the same amounts of TEAL and 1,3-d-ether. 1458 g of propylene liquid, b g of ethylene and 2500 crn3 of H2 were introduced into the autoclave at 25 ° C. The temperature was brought to 70 ° C and the mixture was polyesterised for 120 minutes, adding 12.3 g of ethylene and 2145 cm3 of H2. They obtained 953 g of random poly (propyl ene-ethylene) copolymer having the characteristics reported in table 1.

EXAMPLE 3 0.0178 g of the same component of the solid described in Example 1, 0.457 g of TEAL 0.288 g of 2,2-d? Phenol-1, 3 ~ d? Rnetox? Pro? An as an external donor compound were used. of electrons The same polymerization procedure was followed, introducing 1297 grams of liquid propylene, 12.5 g of etlene and 3000 cm3 of H2 at 25 ° C. The temperature was brought to 70 ° C and the mixture was polished for 120 minutes, adding 27.3 g of ethylene and 2800 cm3 of H2. We obtained 606 g of random copolymer of pol? (? Rop? Leno-et? Leno) that had the characteristics reported in Table 1. 5 EXAMPLE 4 The procedure was carried out using the same catalyst as described in Example 1, using 0.0186 g of the catalyst component with the same amounts of TEAL and 1,3-dieter described in Example 3. 1297.3 g of liquid propylene, 17 g of ethylene and 3000 crn3 of H2 were introduced into the autoclave at 25 ° C. The temperature was brought to 7 ° C and the mixture was polyesterised for 120 minutes, adding 41.3 g of ethylene and 3000 cm3 of H2. 731 g of random copolymer of poly (propylene-ethylene) having the characteristics reported in Table 1 were obtained.

EXAMPLE 5 The procedure was carried out using the same catalyst as described in Example 4, using 0.0142 g of the catalyst component with the same amounts of TEAL and 1,3-d-ether. 1297.3 g of liquid propylene, 20.95 g of ethylene and 3000 cm3 of H2 were introduced into the autoclave at 25 ° C. The temperature was brought to 70 ° C and the mixture was polyrneized for 120 minutes, adding 31.6 g of ethylene and 3000 cm3 of H2. 433 g of poly (propylene-ethylene-leno) random copolymer having the characteristics reported in Table 1 were obtained.

EXAMPLE 6 (comparative) 0.0197 g of the solid catalyst component described in Example 1 were used, with 0.457 g of TEAL and tl.251 g of cyclohexyl eti 1 dirnetox isilane as an external electron donor compound. The same polymerization procedure as described was used. in Example 1, adding 1458.4 g of propy Liquid log, 13. 5 g of ethylene and 2500 crn3 of H 2 at 25 ° C. The temperature was brought to 70 ° C and the mixture was poluted for 120 minutes, adding 20.6 q of ethylene and 2500 crn3 of H2, to obtain 403 g of poly random copolymer (ropyne-ethylene) having the characteristics reported in the Table 1.

EXAMPLE 7 (comparative) 0.17 g of the solid catalyst component described in Example 1 and the same amounts of TEAL and cyclohexylmethyldirnetoxysilane described in Example fa. The same polymerization procedure was used, adding L458 g of liquid propylene, 13.5 g of ethylene and 2500 crn3 of H2 at 25 ° C. The temperature was brought to 70 ° C and the mixture was polyrneppointed for 120 minutes, adding 24.5 g of ethylene and 2500 cm3 of H2 - 6.2 g of copper copolymer was obtained from the olium (propylene-ethylene) subject the characteristics reported in Table 1.

EXAMPLE 8 (comparative) 0.0278 g of the solid catalyst component described in Example L were used, with 0.4567 g of TEAL and 0.3045 g of dicyclopentyl dimethoxysilane as the external donor-electron compound. The same polymerization process was used, adding 1458 g of liquid propylene, 9.7 g of ethylene and 2500 crn3 of H2 at 25 ° C. The temperature was brought to 70 ° C and the mixture was poluted for 120 minutes, adding 19.5 g of thienol and 3000 crn3 of H. 903 g of pol 1 random copolymer (propylene-ethylene) was obtained. to the characteristics reported in Table 1.

EXAMPLE 9 0. 0118 g of solid catalyst component of Example 1 were contacted with 0.457 g of triethylaluminum (TEAL) and 0.0513 g of 2, 2-d? Phen? Ll, 3-d? Methox? Propane in 9 crn3 of hexane in a flask round glass bottom of 50 crn3. The mixture was placed in a 4.25 1 steel autoclave, previously purged, by successively washing with hexane at 80 ° C for 1 hour and then with propylene gas at 80 ° C for 1 hour and then with propylene gas at 80 ° C for 1 hour. 1 hour. 1297.3 g of liquid propylene, 235.6 g of butene and 4950 cm3 of H2 were then introduced at 25 ° C. The temperature was brought to 70 ° C and the mixture polirnepzo for 120 minutes)) add 303 g of propylene. A total of 477 g of copolune was obtained as a result of the use of polypropylene (butene) in the reagents listed in Table 1.

EXAMPLE 10 (Comparative) 0.015 of the solid catalyst component described in Example 1 was used, with 0.4567 g of TEAL v 0.04568 g of dicyclopen? Dunetoxisi as an external donor-electron compound. The same polymerization process was used, adding 1300 g of liquid propylene, 240 g of butene and 4950 cm3 of H2 at 25 ° C. The temperature was brought to 70 ° C and the mixture was poluzed for 120 minutes, adding 255 g of propylene. 960 g of the poly (propylene-butene) random copolymer were obtained, which has the characteristics reported in Table 1.

EXAMPLE 11 After having been adequately stabilized, a copolymer containing 5% by weight of ethylene, obtained according to the process of the present invention, having a content of xylene-soluble fraction equal to 6.6%, was extruded in a film of 50 microns of thickness. The SIT and the amount of hexane-soluble components were determined for the film obtained, according to the procedures described above. The test results are reported in Table 2.

EXAMPLE 12 (comparative) After having been properly stabilized, a propylene copolyel containing 5% by weight of ethylene, obtained using a silane as an external donor, having a content of soluble fraction in x equal to 8.5% is extruded in a film of 50 microns of thickness. The SIT and the amount of hexane-soluble compounds are determined for the film obtained, according to the procedures described above. The test results are reported in table 2.

TABLE 1 TABLE 2

Claims (22)

1. NOVELTY OF THE INVENTION CLAIMS 1. - A Process for the preparation of copolymers of propylene containing up to 15% by weight of ethylene and / or an alpha-olefin CH2-CHRI, wherein R1 is a hydrocarbon radical having from 2 to 10 carbon atoms, said procedure taking a ^ bo > The presence of a catalyst comprising: A solid component comprising a titanium compound supported on magnesium chloride in active form and an electron donor compound; B an alkyl-Al compound; and C an electron donor compound selected from the group of 1,3-dyesters of formula I: wherein R, Ri, Ri 1, RUI, Riv and RV tq? e are identical or different, are hydrogen or linear or branched alkyl radicals, cycloalkyl radicals, aryl radicals, alkylaryl radicals or aplaxyl radicals having 1-18 carbon atoms , with the limitation that R and Rl can not be 2 b simultaneously hydrogen; RVI and RVI1, which are identical or different, are linear or branched alkyl radicals, cycloalkyl radicals, alkyl radicals, alkylaryl radicals or arylalkyl radicals having 1-18 carbon atoms; by at least two of said radicals from R to Rvn can be linked together to form one or more idle structures.
2. 2. A method of contomudad with claim 1, further characterized in that the titanium compound present in the solid component i) contains at least one in Lace of Ti-halogen.
3. 3. A process according to claim 2, further characterized in that the titanium compound has the formula T? (OR) n-y X-y, where X is a halogen, n is the valence of titanium and y is a number between 1 and L5 and.
4. 4. A process according to claim 3, further characterized in that the titanium compound is T1CI4.
5. 5. A process according to claim 1, further characterized in that the internal electron donor compound is selected from esters, ethers, amines, silanes and ketones.
6. 6. A process according to claim 5, further characterized in that the internal electron donor compound is selected from alkyl, cycloalkyl or aryl esters of nonocarboxylic acids such as benzoic acid and polycarboxylic acids such as phthalic or aleic acids, said alkyl, cycloalkyl or aryl groups having from 1 to 18 carbon atoms.
7. 7. A process according to claim 1, further characterized in that the solid component A has a surface area of between 20 and 400 rn2 / g and preferably between 50 and 350? N2 / g, and a greater porosity of 0. 2 em3 / g, preferably between 0.2 and 0.5 crn / g.
8. 8. A process according to claim 1, further characterized in that the alkyl-Al B compound is selected from the following t-alkyl-Als: t-butyl-Al, t-Lo-Al, t-butyl-yl-Al, t-n-butyl -Al, tp ~ n ~ oct-lo-Al.
9. 9. A process according to claim 1, further characterized in that the electron-donor compound C is selected from 1,3-d-ethers of the formula 1 wherein at least one of R and R1 is a secondary hydrocarbon radical or tertiary of the alkyl, cycloalkyl or aromatic type.
10. 10. A process according to claim 9, further characterized in that at least one of R and Ri is selected from isopropyl, sec-butyl, tert-butyl, cyclobutyl, cyclopentyl and phenyl, which are optionally substituted, and in the which RVI and RVI * are preferably methyl, while R1 1, R1 J *, RIV and Rv are preferably hydrogen. 11. - A method according to claim LO, further characterized in that the donor compound (je electrons C is selected from:?, 2-d? Feml-l, 3-dirnetox i propane, 2, 2- bis (cyclohexylrnet? l) -i, 3- duneto and propane, 2, 2-d? so? rop? l- 1, 3-d? metox? prop? no, -iso ropil -2-c? clohex? l-met il - 1, 3 - dinetoxy propane, 2, 2-d? C? clopentj 1- 1, 3-d? rnetox? -propane, and 2--? sopro? l ~ 2 ~? sopent? -i, 3 ~ d? rnetox? pr? pano "12.- A method according to claim 1, further characterized in that the alpha olefin of formula CH2 = CHR is butene or hexene. 13. - A method according to claim 1, further characterized in that the polymerization is carried out in suspension, using inert hydrocarbon diluents as a liquid phase. 14. A process according to claim 13, further characterized in that the process is carried out in liquid propylene. 15. A process according to claim 1, further characterized in that the polymerization is carried out at temperatures between 20 and 120C >; C and under pressures between 0.5 and 10 MPa. 16.- Random copolymers of propylene-wood which have the following characteristics: content of ethylemcae units between 0.1 and 15% by weight; molecular weight distribution, in terms of (riPp / Pt1n), greater than 2.5; catalytic residue content, expressed in terms of pprn of Ti, less than 15; natural logarithm of the percentage by weight of fraction soluble in xylene and content by weight of ethyl units, calculated on the basis of the total polymer, such that the point defined by said values "." ae below the straight line given by the equation ln (Xs) - ln (a) - + C2 in which: Xs -% by weight is the fraction soluble in x full at 25 ° C; C2 -% by weight of ethylene units in the copolymer; a - 1.73; b - 0.29. 17. Copolymers according to claim 16, further characterized in that the content of ethylene units is between 0.5 and 10% and preferably between 1 and 6%. 18. Copoluneros according to claim 16, further characterized in that they have a molecular weight distribution greater than 3 and most preferably more than 3.5. 19.- Copolings in accordance with the claim 16, further characterized in that the amount of catalytic residues is preferably less than 10 and most preferably less than 2 pprn of Ti. 20. Copolymers in accordance with one or more of claims 16 to 19, having a natural logarithm of the percentage by weight of fraction soluble in xylene and a content by weight of ethylene units, calculated on the basis of the total polymer, so that the point defined by said value is falls below the straight line given by the equation: ln (Xs) = ln (a) + bC2, where: a = 1.68, and most preferably = 1.55; and b = 0.29. 21. - Random copolymers of propylene-ethylene having the following characteristics: content of ethylene units of between 0.1 and 15% by weight; molecular weight distribution, in terms of (MPp / PMn), greater than 2.5; catalytic residue content, expressed in terms of pprn of Ti, less than 15; a natural logarithm of the content ratio of soluble components of xylene / melting point, in correspondence with the value of the cornonornero content, in such a way that the point defined by said values falls below the straight line given by the equation: ln (Xs / Trn) - ln (c) «• dC2, where: Xs =% by weight of the fraction soluble in xylene at 25 ° C; C2 =% by weight of ethylene units in the copolymer; c = 0.009; d = 0.32. 22. Random copolymers of propylene-butene having the following characteristics: content of ethylene units of between 0.1 and 15% by weight; molecular weight distribution, in terms of (MPp / Ppn), greater than 2.5; catalytic residue content, expressed in terms of pprn of Ti, less than 15; natural logarithm of the percentage by weight of fraction soluble in xylene and percentage by weight of units of butene, calculated on the basis of the total polymer, in such a way that the point defined by these values falls below the straight line given by the equation: ln (Xs) = ln (e) + fC «where: Xs -% by weight of the fraction soluble in xylene at 25 ° C; C4 =% by weight of butene units in the copolymer; e = 1.57; f = 0.08.