Abstract: Copolymers of ethylene with comonomers selected from (a) alpha-olefins, (b) cycloolefins and/or (c) dienes, characterized by the fact that:the molar percentage of the comonomer (% .alpha.) and the density of the copolymer (D) satisfy the relation % .alpha.+150D.ltoreq.141.

Abstract: A catalyst for the polymerization of olefins comprises the product obtained by contacting:(A) a titanium, zirconium or hafnium mono- or bis-cyclopentadienyl compound, this latter optionally containing a bridging group which links the two cyclopentadienyl compounds;(B) an alkyl aluminium wherein at least one alkyl is different from a straight alkyl; and(C) water.The molar ratio aluminium/water is higher than 1:1 and lower than 100:1.

Abstract: Process for preparing elastomeric copolymers of ethylene with .alpha.-olefins CH.sub.2 .dbd.CHR, optionally containing minor proportions of a diene, characterized by the use during the polymerization of a catalyst comprising the reaction product of:(I) a solid component comprising VCl.sub.3 supported on a magnesium dihalide in spherical or spheroidal shape, in active form;(II) an alkyaluminum compound;(III) optionally a halohydrocarbon.VCl.sub.3 is precipitated on said magnesium dihalide by heating VCl.sub.4 solutions in inert hydrocarbon solvents.

Abstract: Polypropylene compositions having valued plasto-elastic properties, in the form of spheroidal flowable particles with an average diameter included between 500 and 7000 um having the following composition:A) 10-60 parts by weight of homopolymer polypropylene with isotactic index greater than 90, or of crystalline propylene copolymer with ethylene and/or an alpha olefin such as butene-1, pentene-1 or 4-methyl-1-pentene, containing over 85% by weight of propylene and having an isotactic index greater than 85;B) 10-40 parts by weight of a polymer fraction containing ethylene, insoluble in xylene at room temperature;C) 30-60 parts by weight of an amorphous copolymer ethylene-propylene fraction optionally containing small proportions of a diene, soluble in xylene at room temperature and containing 40-70% by weight of ethylene.

Abstract: Propylene polymer compositions having good transparency and improved impact resistance at low temperature comprising:a) 70 to 98% by weight crystalline copolymer of ethylene with propylene and/or with an alpha olefin of the formula H.sub.2 C=CHR where R is a C.sub.2-8 linear or branched alkyl radical and b) 2 to 30% by weight of an elastomeric propylene-ethylene copolymer. The portion of said copolymer b) soluble in xylene at room temperature has an intrinsic viscosity (I.V. 2) which satisfies the following relation:0.2.ltoreq.(I.V. 2/I.V. 1).times.(C.sub.2.sup.-).ltoreq.0.6where I.V. 1 is the intrinsic viscosity of the crystalline propylene copolymer, (C.sub.2.sup.-) is the ethylene weight content of b). The ratio between the ethylene weight content in b) and the weight of the xylene soluble portion is equal to or less than 1.5.

Abstract: Elastoplastic polyolefin compositions endowed with high flexibility, comprising:A) 10-50 parts by weight of a homopolymer of propylene with isotactic index greater than 80, or a copolymer of propylene with ethylene, another .alpha.-olefin, or combinations thereof, which copolymer contains over 85% by weight of propylene;B) 5-20 parts by weight of a copolymer fraction containing ethylene, insoluble in xylene at ambient temperature;C) 40-80 parts by weight of a copolymer fraction of ethylene and propylene or another .alpha.-olefin, or combinations thereof, and, optionally, minor portions of a diene, said fraction containing less than 40% by weight of ethylene, being soluble in xylene at ambient temperature, and having an intrinsic viscosity from 1.5 to 4 dl/g; the percent by weight of the sum of the (B) and (C) fractions with respect to the total polyolefin composition being of from 50% to 90% and the (B)/(C) weight ratio being lower than 0.4.

Abstract: Disclosed are polypropylene compositions having high impact resistance at low temperatures, and improved whitening resistance. They comprise:(a) 60-90 parts by weight of polypropylene with an isotacticity index >90; and(b) 10-40 parts by weight of an ethylene/butene-1 polymeric mixture containing 50-95% by weight of polymerized ethylene, and consisting essentially of:20-95% by weight of a crystalline fraction (I) with crystallinity of the polyethylene type, that is insoluble in xylene at 23.degree. C.; and5-80% by weight of an ethylene/butene-1 amorphous copolymeric fraction (II), that is soluble in xylene at 23.degree. C., and contains 40-70% by weight of ethylene;and in which the weight ratio between total polymerized ethylene and the amorphous fraction (II) is 0.6-8.

Abstract: Disclosed are plastic copolymers of propylene with linear dienes having conjugated double bonds, in particular with butadiene, characterized by a molar ratio between the dienic units in configuration 1,2 and those in configuration 1,4 higher than 0.2, preferably higher than 1.Such copolymers are prepared by copolymerization of propylene with linear dienes in the presence of stereospecific catalysts comprising a halogen Ti compound supported on a Mg halide.The copolymers can be reacted with radically polymerizable monomers, thus obtaining functionalized products suited to be transformed into films having good adhesion characteristics.