摘要:
Polyolefin compositions comprising (percent by weight) A) 60%-95% of a crystalline polypropylene component having a Melt Flow Rate (MFRA) value of from 2.5 to 50 g/10 min. and containing from 20% to 80% of a fraction AI) having MFRI from 0.5 to 8 g/10 min., and from 20% to 80% of a fraction AII); B) 5%-40% of a copolymer of ethylene with one or more C4-C10 &agr;-olefin(s) containing from 10 to 40% of said C4-C10 &agr;-olefin(s); the ratio MFRA/MFRI being from 2 to 25; the percentages of A) and B) being referred to the sum of A) and B), and the percentages of AI) and AII) being referred to the sun of AI) and AII).
摘要:
Crystalline polymers and copolymers of propylene having total MIL values>2 g/10 minutes, total [η] values in tetrahydronaphthalene at 135° C.≦2.8 dl/g, mW/MN values>20, a fraction insoluble in xylene at 25° C.≧94, and including from 10 to 60% by weight of a fraction (A) having [η]≧2.6, are prepared by way of sequential polymerization in at least two stages, in the presence of a particular Ziegler-Natta catalysts supported on magnesium halides. These polymers have high melt strength, high mechanical properties, and are particularly adequate for the manufacture of articles by using various conversion technologies, such as for example extrusion in thin sheets to be subjected to thermoforming, as well as for injection molding, and blow molding.
摘要:
Crystalline polymers and copolymers of propylene having total MIL values>2 g/10 minutes, total [η] values in tetrahydronaphthalene at 135° C.≦2.8 dl/g, Mw/Mn values>20, a fraction insoluble in xylene at 25° C.≧94, and including from 10 to 60% by weight of a fraction (A) having [η]≧2.6, are prepared by way of sequential polymerization in at least two stages, in the presence of a particular Ziegler-Natta catalysts supported on magnesium halides. These polymers have high melt strength, high mechanical properties, and are particularly adequate for the manufacture of articles by using various conversion technologies, such as for example extrusion in thin sheets to be subjected to thermoforming, as well as for injection molding, and blow molding.
摘要:
Crystalline polymers and copolymers of propylene having total MIL values>2 g/10 minutes, total [η] values in tetrahydronaphthalene at 135° C.≦2/8 dl/g, Mw/Mn values>20, a fraction insoluble in xylene at 25° C.≧94, and including from 10 to 60% by weight of a fraction (A) having [η]≧2.6, are prepared by way of sequential polymerization in at least two stages, in the presence of particular Ziegler-Natta catalysts supported on magnesium halides. These polymers have high melt strength, high mechanical properties, and are particularly adequate for the manufacture of articles by using various conversion technologies, such as for example extrusion in thin sheets to be subjected to thermoforming, as well as for injection molding, and blow molding.
摘要:
A crystalline propylene copolymer composition having MFR L values from 2 to 15 g/10 min. and comprising (percent by weight): A) 20-80% of one or more propylene copolymers; B) 20-80% of one or more propylene copolymers with different comonomer(s) content than in A); the said MFR L values (MFR L (2)) being obtained by subjecting to degradation a precursor composition comprising the same components A) and B) in the above said proportions, but having MFR L values (MFR L (1)) from 0.3 to 5 g/10 min., with a ratio MFR L (2) to MFR L (1) of from 2 to 20.
摘要:
A multistage process comprising the step of polymerizing propylene in the presence of a catalysts system, comprising one or more metallocene compound of formula (I): wherein M is an atom of a transition metal; p is an integer from 0 to 3, X, same or different, is a hydrogen atom, a halogen atom, or a hydrocarbon group; L is a divalent bridging R1 and R2, are C1-C20-alkyl radicals; T, equal to or different from each other, is a moiety of formula (IIb) or (IIa): wherein R3, R4, R5, R6, R7, R3′, R4′, R5′, R6′, R7′, are hydrogen atoms or hydrocarbon groups; with the proviso that at least one among R3, R4, R5, R6, R7 is different from hydrogen; R11 is a hydrogen atom or a hydrocarbon group; R8, R9 and R10, are hydrogen atoms or hydrocarbon groups; and further comprising the step of contacting, under polymerization conditions, in a gas phase, ethylene and one or more comonomers. Where the amount of the polymer obtained in the first step ranges from 4% by weight and 20% by weight, extremes excluded, of the polymer obtained in the whole process.
摘要:
A polyolefin composition comprising (percentage by weight): (A) from 40 to 60% of a broad molecular weight distribution propylene polymer (component A) having a polydispersity index from 5 to 15 and melt flow rate of from 80 to 200 g/10 min (according to ASTM-D 1238, condition L); and (B) from 40 to 60% of a partially xylene-insoluble olefin polymer rubber (component B) containing at least 65% by weight of ethylene; the IVS/IVA ratio between the intrinsic viscosity (IVS) of the portion soluble in xylene of the polyolefin composition at room temperature and the intrinsic viscosity (IVA) of component (A) ranging from 2 to 2.5, both values on intrinsic viscosity being measured in tetrahydronaphthalene at 135° C. Said composition finds application in automotive field.
摘要:
A multistage process for obtaining an heterophasic propylene polymer comprising the following steps: step a) contacting under polymerization conditions propylene and optionally ethylene or one or more alpha olefins in the presence of a catalysts system, supported on a porous organic polymer, comprising: ii) one or more metallocene compounds of formula (I) wherein: M is an atom of a transition metal; p is an integer from 0 to 3; X, same or different, is a hydrogen atom, a halogen atom, or a hydrocarbon group; L is a divalent bridging group; R1, is a linear or branched, saturated or unsaturated C1-C20-alkyl radical; R2 is a branched C1-C20alkyl radical; T, equal to or different from each other, is a moiety of formula (IIIa) or (IIIb): wherein: the atom marked with the symbol * bonds the atom marked with the same symbol in the compound of formula (I); R5-R13, equal to or different from each other, are hydrogen atoms or hydrocarbon groups; ii) an alumoxane or a compound capable of forming an alkyl metallocene cation; and optionally iii) an organo aluminium compound; step b) contacting, under polymerization conditions, in a gas phase, ethylene and one or more alpha olefins and optionally a non-conjugated diene, in the presence of the polymer obtained in step a) and optionally in the presence of an additional organo aluminium compound.
摘要翻译:用于获得多相丙烯聚合物的多阶段方法包括以下步骤:步骤a)在负载在多孔有机聚合物上的催化剂体系存在下,在聚合条件下使丙烯和任选的乙烯或一种或多种α-烯烃接触,包括:ii) 一种或多种式(I)的茂金属化合物,其中:M是过渡金属的原子; p是0至3的整数; X相同或不同,是氢原子,卤素原子或烃基; L是二价桥基; R 1是直链或支链饱和或不饱和的C 1 -C 20 - 烷基; R 2是支链C 1 -C 20烷基; T是相同或不同的,是式(IIIa)或(IIIb)的部分:其中:用符号*标记的原子与式(I)化合物中与相同符号标记的原子键合; R 5相同或不同,为氢原子或烃基; ii)铝氧烷或能够形成烷基茂金属阳离子的化合物; 和任选地iii)有机铝化合物; 步骤b)在聚合条件下,在步骤a)中获得的聚合物存在下,任选地在另外的有机铝存在下,在气相乙烯和一种或多种α-烯烃和任选的非共轭二烯中, 复合。
摘要:
A method for feeding an antistatic compound to a polymerization reactor, the method comprising the steps of: a) dispersing, under mixing conditions, a catalyst powder and an antistatic compound in a liquid medium, so as to form a suspension of the catalyst powder and of the antistatic compound in the liquid medium; b) transferring the obtained suspension to a polymerization reactor.
摘要:
A movable mass forming a seismic mass is formed starting from an epitaxial layer and is covered by a weighting region of tungsten which has high density. To manufacture the mass, buried conductive regions are formed in the substrate. Then, at the same time, a sacrificial region is formed in the zone where the movable mass is to be formed and oxide insulating regions are formed on the buried conductive regions so as to partially cover them. An epitaxial layer is then grown, using a nucleus region. A tungsten layer is deposited and defined and, using a silicon carbide layer as mask, the suspended structure is defined. Finally, the sacrificial region is removed, forming an air gap.