Abstract: A copolymer of ethylene, a catalyst system suitable to prepare the copolymer, and a process to prepare such copolymer are described. The copolymer comprises from 60 to 80% by weight of ethylene and from 20 to 40% by weight of at least one first ?-olefin comonomer having n carbon atoms and at least one second ?-olefin comonomer having (n?1) carbon atoms, n being from 4 to 13, has a polydispersity Mw/Mn equal to or lower than 3.5, and a density from 0.855 to 0.880 g/cm3. The copolymer is obtained by subjecting ethylene and said at least one first ?-olefin comonomer to a polymerization stage in the presence of a catalyst system capable of forming a copolymer of ethylene and said at least one first ?-olefin comonomer having n carbon atoms, while forming the second ?-olefin comonomer having (n?1) carbon atoms.

Abstract: Described herein are methods for monitoring and restoring electrical properties of polymerization reactor wall films. The method may comprise using a reactor wall monitor to monitor and determine an electrical property, such as the bed voltage or breakdown voltage, of the wall film. The method may further comprise adding continuity additive to the reactor and/or adjusting the feed rate of continuity additive being added to the reactor in response to the measured electrical property.

Abstract: This invention relates to a polyolefin composition comprising one or more of the following formulae: wherein the PO is the residual portion of a vinyl terminated macromonomer (VTM) having had a terminal unsaturated carbon of an allylic chain and a vinyl carbon adjacent to the terminal unsaturated carbon; and wherein the VTM is preferably a vinyl terminated polymer having greater than 30% allyl chain ends with an Mn of greater than 10,000.

Abstract: The present invention relates to a process of forming a polymer, the process comprising polymerizing olefin monomers to form a reaction mixture, treating the reaction mixture to form a first polymer-rich phase, treating the first polymer-rich phase to form a second polymer-rich phase, and devolatilizing the second polymer-rich phase, the process further comprising at least one step of adjusting the temperature of a first and/or the second polymer-rich phase before the devolatilization. The present invention also relates to a plant that is useful for the process provided above.

Abstract: A molded polyethylene component that comprises polyethylene having a melt flow index of about 3.5 g/10 min or greater as measured by ASTM D1238 at 190° C./21.5 kg weight and having an ash content of about 500 ppm or less may be useful biomedical devices, including kits and methods relating thereto.

Abstract: A novel polymer composition is described comprising ethylene homopolymers and/or copolymers of ethylene with C3-C8-alpha-olefins which polymer composition has a density of from 0.940 to 0.949 g/cm3, a melt index (HLMI) according to DIN EN ISO 1133:2005, condition G at 190° C. and 21.6 kg, of from 3 to 7 g/10 min. and a Hostalen Long Chain Branching Index (HLCBI) of from 3 to 8, and which polymer composition is produced by polymerisation with one or more Ziegler catalysts in a series of at least two polymerization reactors. The new polymer composition can in particular be used for blow moulding of intermediate bulk containers.

Abstract: An inventive composition that has utility as an article for cleaning a target surface is provided. Embodiments of the inventive composition are readily applied to a substrate to form a cleaning article or form a free-standing article; the composition upon drying forms a matrix having a coefficient of friction of greater than one, and a glass transition temperature that is between 0° C. and 40° C. The matrix is amenable to loading with various additives illustratively including re-enforcing fibers, abrasives, plasticizers, foaming agents, fragrances, and combinations thereof. Embodiments of the inventive composition operate to clean a substrate such as a vehicle and ideally return the same to the original look and feel without requiring excessive work, or requiring the removal of too much material from the surface.

Abstract: Preparation of high-reactivity isobutene homo- or copolymers with a content of terminal vinylidene double bonds per polyisobutene chain end of at least 50 mol % and a polydispersity of preferably 1.05 to less than 3.5, by polymerizing isobutene or an isobutene-comprising monomer mixture in the presence of an aluminum trihalide-donor complex effective as a polymerization catalyst or of an alkylaluminum halide-donor complex, especially of an aluminum trichloride-donor complex, said complex comprising, as the donor, an organic compound with at least one ether function or a carboxylic ester function.

Abstract: Propylene copolymer (a) comprising at least 1-butene as a comonomer, (b) having a comonomer content in the range of 1.0 to 3.0 wt.-%, (c) having a xylene soluble fraction equal or below 2.5 wt.-%, and (d) being partially crystallized in the ?-modification.

Abstract: An optical resin comprises a copolymer of 4-methyl-1-pentene and at least one monomer selected from the group consisting of 3-methyl-1-pentene, 3-methyl-1-butene and 4,4-dimethyl-1-pentene. The content of a constituent unit (a) derived from 4-methyl-1-pentene is equal to or more than 60 mol % and equal to or less than 99 mol %, and the total content of a constituent unit (b) derived from at least one monomer selected from the group consisting of 3-methyl-1-pentene, 3-methyl-1-butene and 4,4-dimethyl-1-pentene is equal to or more than 1 mol % and equal to or less than 40 mol %.

Abstract: The present invention relates to an apparatus and process for the gas phase polymerisation of olefins, the apparatus comprising: a) a reaction zone comprising a grid at its base, b) an inlet located in the lower half of the reaction zone for introduction of a reaction gas to the reaction zone, c) an outlet located in the upper half of the reaction zone for removal of the reaction gas from the reaction zone, and d) a solids separation unit having an inlet fluidly connected to the outlet for removal of the reaction gas from the reaction zone, characterised in that the inlet of the solids separation unit is located at a vertical height lower than the outlet for removal of reaction gas from the reaction zone and such that the angle to the horizontal of a straight line drawn between the inlet of the solids separation unit and the outlet for removal of reaction gas from the reaction zone is greater than 20°.

Abstract: The present invention provides dual catalyst systems containing a metallocene catalyst and a hydrogen scavenging catalyst, and polymerization processes employing these dual catalyst systems. Due to a reduction in hydrogen levels in the polymerization processes, olefin polymers produced from these polymerization processes may have a higher molecular weight, a lower melt index, and higher levels of unsaturation.

Abstract: A novel gas phase polymerisation method is devised, for polymerisation of low and ultralow density polyethylene.

Abstract: The present invention relates to an ethylene-alpha olefin copolymer comprising long chain branches (LCB), while having a narrow molecular weight distribution. The ethylene-alpha olefin copolymer can be prepared by a continuous solution polymerization process using an activated catalyst composition containing a Group 4 transition metal compound having a monocyclopentadienyl ligand, to which a quinoline amino group is introduced.

Abstract: The present invention relates to a process for producing free-flowing, agglomeration resistant amorphous poly-alpha-olefin based adhesive pellets. The process includes (a) extruding the adhesive through an orifice of a die plate immersed in a cooling fluid; (b) cutting the adhesive into a plurality of pellets in the cooling fluid; (c) solidifying the pellets at a temperature range of about 25° C. to about 40° C. for at least 30 minutes; and (d) separating the pellets from the recrystallization fluid and drying the pellets. The pellets harden at least three folds faster than conventionally formed pellets.

Abstract: Polyethylene which comprises ethylene homopolymers and copolymers of ethylene with ?-olefins and has a molar mass distribution width Mw/Mn of from 6 to 100, a density of from 0.89 to 0.97 g/cm3, a weight average molar mass Mw of from 5000 g/mol to 700 000 g/mol and has from 0.01 to 20 branches/1000 carbon atoms and at least 0.5 vinyl groups/1000 carbon atoms, wherein the 5-50% by weight of the polyethylene having the lowest molar masses have a degree of branching of less than 10 branches/1000 carbon atoms and the 5-50% by weight of the polyethylene having the highest molar masses have a degree of branching of more than 2 branches/1000 carbon atoms, a process for its preparation, catalysts suitable for its preparation and also fibers, moldings, films or polymer blends in which this polyethylene is present.

Abstract: A process for the preparation of a fluoroolefin polymer from an azeotropic mixture of monomers having a constant composition, the process including the step of: contacting in a reaction zone: (i) an initiator; and (ii) an azeotropic mixture of monomers including at least one fluoroolefin and, optionally, at least one ethylenically unsaturated comonomer capable of copolymerizing therewith; wherein the contacting is carried out at a temperature, pressure and length of time sufficient to produce the fluoroolefin polymer.

Abstract: Polyolefin based sealing element compositions with good oxygen barrier properties particularly suitable for forming sealing elements, for example gaskets and cap liners that are especially useful for sealing containers having products such as liquids or food-stuffs therein. The compositions when formed as sealing elements do not appreciably contribute taste and/or odor to a packaged product including the sealing element. The compositions have desirable rheological properties and are thus readily processable at various temperatures.

Abstract: A Ziegler-Natta catalyzed ethylene copolymer having a novel composition distribution in which comonomers are incorporated into the high molecular weight polymer molecules and distributed evenly among the entire polyethylene chains, and a method for making the same are provided. The resins having a novel composition distribution have controlled molecular weight distribution which is narrower than conventional ZN-ethylene copolymers but broader than single-site catalyzed ethylene copolymers. The resins having a novel composition distribution exhibit a superior tear strength and impact strength.

Abstract: The present invention relates to modified polyolefins with atactic structural elements, to processes for preparation thereof and to the use thereof, especially as an adhesive or as a constituent of adhesives.

Abstract: An encapsulating material for solar cell excellent in a balance among properties including transparency, flexibility, adhesiveness, heat resistance, appearance, crosslinking properties, electrical properties and calender moldability. The encapsulating material includes an ethylene/?-olefin copolymer satisfying the following requirements: (a1) the content ratio of structural units derived from ethylene is from 80 to 90 mol % and the content ratio of structural units derived from ?-olefin having 3 to 20 carbon atoms is from 10 to 20 mol %; (a2) MFR is equal to or more than 2 g/10 minutes and less than 10 g/10 minutes as measured under the conditions of a temperature of 190 degrees centigrade and a load of 2.16 kg in accordance with ASTM D1238; (a3) the density is from 0.865 to 0.884 g/cm3 as measured in accordance with ASTM D1505; and (a4) the shore A hardness is from 60 to 85 as measured in accordance with ASTM D2240.

Abstract: The present invention relates to an ethylene-alpha olefin copolymer comprising long chain branches (LCB), while having a narrow molecular weight distribution. The ethylene-alpha olefin copolymer can be prepared by a continuous solution polymerization process using an activated catalyst composition containing a Group 4 transition metal compound having a monocyclopentadienyl ligand, to which a quinoline amino group is introduced.

Abstract: Pressure sensitive adhesive composition and multilayer easy peel re-closable structures thereof, comprising a butene-1 (co)polymer (A) having a content of butene-1 derived units of 80 wt % or more; a flexural modulus (MEF) of 80 MPa or less; a melting temperature DSC (TmI) lower than 110° C., and optionally a tackifier (B).

Abstract: A polymer having a density of from about 0.94 g/cm3 to about 0.96 g/cm3 and a primary structure parameter 2 (PSP2 value) of greater than about 8.5, wherein an article formed from the polymer has an environmental stress crack resistance of equal to or greater than about 1000 hours when measured in accordance with ASTM D 1693 condition A. A polymer having at least one lower molecular weight component and at least one higher molecular weight component and having a PSP2 value of equal to or greater than about 8.5, wherein an article formed from the polymer has an environmental stress crack resistance of greater than about 1000 hours when measured in accordance with ASTM D 1693 condition A.

Abstract: The instant invention provides rotational molded articles, and method of making the same. The rotational molded articles according to the present invention comprise a polyethylene composition comprising: (a) at least 85 percent by weight of the units derived from ethylene; and (b) less than 15 percent by weight of units derived from one or more ?-olefin comonomers; wherein the polyethylene composition has a density in the range of 0.930 to 0.945 g/cm3, a molecular weight distribution (Mw/Mn) in the range of 1.70 to 3.50, a melt index (I2) in the range of 0.5 to 20 g/10 minutes, a molecular weight distribution (Mz/Mw) in the range of less than 2.5, vinyl unsaturation of less than 0.06 vinyls per one thousand carbon atoms present in the backbone of the polyethylene composition.

Abstract: The invention relates to a hot-melt adhesive substance for sticking together fibrous materials such as matted nonwovens or woven textiles with smooth substrate surfaces, such as plastic or metal films, and for laminating said materials. Said substance is characterized in that it contains at least one polyolefin which has been produced by polymerization in the presence of metallocene as a catalyst and has a ring/ball softening point of between 50 and 165° C. and a melting viscosity, measured at a temperature of 170° C., of between 20 and 40,000 mPa-s. The hot-melt adhesive substance can also contain at least one adhesive component and is used in a quantity of between 3 and 6 g/m2, preferably between 4 and 5.5 g/m2, for sticking a film to a nonwoven material during the production of hygiene items such as disposable nappies, baby nappies, incontinence products, panty liners and/or sanitary towels.

Abstract: The instant invention is a polyethylene composition, method of producing the same, articles made therefrom, and method of making the same. The polyethylene composition according to the instant invention comprises (1) less than or equal to 100 percent by weight of the units derived from ethylene; and (2) less than 15 percent by weight of units derived from one or more ?-olefin comonomers. The polyethylene composition according the instant invention has a density of equal to D g/cm3, wherein D=[(0.0034(Ln(I2))+0.9553], wherein I2 is melt index expressed in g/10 min, a molecular weight distribution (Mw/Mn) in the range of 1.70 to 3.62, a melt index (I2) in the range of 2 to 1000 g/10 minutes, a molecular weight distribution (Mz/Mw) in the range of less than 2.5, and a vinyl unsaturation of less than 0.06 vinyls per one thousand carbon atoms present in the backbone of the composition.

Abstract: Use of a metallocene compound of general formula Ind2R?MQ2 as a component of a catalyst system in producing polyethylene, wherein each Ind is the same or different and is indenyl or substituted indenyl; R? is a bridge which comprises a C1 to C4 alkylene radical, a dialkyl germanium or silicon or siloxane, alkyl phosphine or amine, which bridge is substituted or unsubstituted, M is a Group IV metal or vanadium and each Q is hydrocarbyl having 1 to 20 carbon atoms or halogen; and the ratio of meso to racemic forms of the metallocene in the catalyst system is at least 1:3. The metallocene may be supported. The ethylene may be polymerized in a reaction medium that is substantially free of any external comonomer, with comonomer being formed in situ. The produced polyethylene may have long chain branching. The produced polyethylene may be atactic.

Abstract: The present invention provides a polymerization process which is conducted by contacting an olefin monomer and at least one olefin comonomer in the presence of hydrogen and a metallocene-based catalyst composition. Polymers produced from the polymerization process are also provided, and these polymers have a reverse comonomer distribution, low levels of long chain branches, and a ratio of Mw/Mn from about 3 to about 6.

Abstract: The present invention relates to an activated silane compound obtained by reacting a hydrocarbyloxysilane compound with an organic metal compound in an organic solvent, and enhancing interaction of silica with carbon black and improving the fracture characteristic, the abrasion resistance and the low heating property provide an activated silane compound which can be reduced in a blending amount, a rubber composition prepared by blending it as a silane coupling agent and a pneumatic tire prepared by using the above rubber composition, which is excellent in a durability, a low heating property and the like.

Abstract: Disclosed is an ethylenic polymer having a long characteristic relaxation time. The ethylenic polymer satisfies the following requirements: (a) the ethylenic polymer is a non-crosslinked ethylenic polymer; (b) the number of long-chain branches (LCB) per 1000 carbon atoms is 0.1-1.5 inclusive; (c) the intrinsic viscosity [?] is 1.0-3.0 dl/g inclusive; and (d) the ratio (G?/G?) of the storage modulus (G?) to the loss modulus (G?), determined by dynamic viscoelasticity measurement at 190° C. and at an angular frequency of 0.1 rad/sec is 0.8 or more and 4.0 or less.

Abstract: It has been discovered that amorphous polybutene copolymers that have a softening point of from about 70 to about 105° C. and viscosity of less than about 1,900 cP at 190° C. possesses desirable properties and may be used to make a low application temperature hot melt adhesive for disposable absorbent articles.

Abstract: A multimodal linear low density polyethylene polymer having a final density of 900 to 940 kg/m3, and containing at least one ?-olefin comonomer in addition to ethylene comprising: (A) 30 to 60 wt % of a lower molecular weight component being an ethylene homopolymer or a copolymer of ethylene and at least one ?-olefin; and (B) 70 to 40 wt % of a higher molecular weight component being a copolymer of ethylene and at least one ?-olefin, said ?-olefin being the same or different from any ?-olefin used in component (A) but with the proviso that both components (A) and (B) are not polymers of ethylene and butane alone; wherein the multimodal LLDPE has a dart drop of at least 700 g; and wherein components (A) and (B) are obtainable using a Ziegler-Natta catalyst.

Abstract: The time between shut downs of a gas phase reactor for the polymerization of polyethylene may be significantly increased if the catalyst used is not prepared by impregnating the support with a solution of catalyst in an electron donor; the reaction is controlled using the addition of activator based on polymer production rate and the recycle stream contains a condensed liquid phase in an amount greater than 13 weight %. Operating the reactor in this manner increase the time between cleaning the cooler (heat exchanger) the bed plate, or both from about 4 to 6 months to not less than about 24 months.

Abstract: The present techniques relate to catalyst compositions, methods, and polymers encompassing a Group 4 metallocene compound comprising bridging ?5-cyclopentadienyl-type ligands, typically in combination with a cocatalyst, and a activator. The compositions and methods presented herein include ethylene polymers with low melt elasticity.

Abstract: The present invention relates to a propylene-butene-1 random copolymer which has a butene-1 content of 1-6 mol % and a relative dispersity of butene-1, as determined according to NMR method, of greater than 98.5%. The propylene-butene-1 random copolymer of the present invention has a high relative dispersity of butene-1, as well as better transparency and heat resistance, so that it is more suitable for packaging food that may be edible after heating. Moreover, the copolymer has a lower xylene solubles content at room temperature. In addition, the present invention further relates to a method for preparing the copolymer and to a composition and an article comprising the copolymer.

Abstract: The present invention provides a non-metallocene transition metal compound that is easily produced, includes a tetrazol group having the high polymerization activity and high temperature stability in the polymerization of olefins, and a catalytic composition that includes the transition metal compound and a cocatalyst. In addition, the present invention provides a method for efficiently producing an olefin homopolymer or copolymer by using the catalytic composition.

Abstract: This invention relates to a polymacromonomer comprising at least one macromonomer and from 0 to 20 wt % of a C2 to C12 comonomer, wherein the macromonomer has vinyl termination of at least 70%, and wherein the polymacromonomer has: a) a g value of less than 0.6, b) an Mw of greater than 30,000 g/mol, c) an Mn of greater than 20,000 g/mol, d) a branching index (g?)vis of less than 0.5, e) less than 25% vinyl terminations, f) at least 70 wt % macromonomer, based upon the weight of the polymacromonomer, g) from 0 to 20 wt % aromatic containing monomer, based upon the weight of the polymacromonomer and h) optionally, a melting point of 50° C. or more. This invention also relates to processes to make such polymacromonomers.

Abstract: This invention relates to the field of olefin polymerization catalyst compositions, and methods for the polymerization and copolymerization of olefins, including polymerization methods using a supported catalyst composition. In one aspect, the present invention encompasses a catalyst composition comprising the contact product of a first metallocene compound, a second metallocene compound, at least one chemically-treated solid oxide, and at least one organoaluminum compound. The new resins were characterized by useful properties in impact, tear, adhesion, sealing, extruder motor loads and pressures at comparable melt index values, and neck-in and draw-down.

Abstract: The present invention relates to an olefin-based polymer which exhibits superior processability and superior adhesive properties and therefore is desirably applicable to a hot-melt adhesive (HMA) or the like, and a preparation method thereof. The olefin-based polymer has a molecular weight distribution (Mw/Mn, PDI) of 2˜3, and a density of 0.85 to 0.88 g/cm3, and satisfies the relation of Tc?Tm>0, wherein Tc (° C.) is a crystallization temperature and Tm (° C.) is a melting point.

Abstract: A process is disclosed for producing a multi-modal linear low density polyethylene in at least two staged reactors connected in series, comprising (i) polymerizing in a first slurry phase stage ethylene monomers with a Ziegler-Natta polymerization catalyst system to obtain a first polyethylene fraction component (A); and (ii) polymerizing in a second gas or slurry phase stage ethylene monomers with a Ziegler-Natta polymerization catalyst system to obtain a second polyethylene fraction component (B). The Ziegler-Natta polymerization catalyst system comprises: 1) a solid procatalyst formed by contacting at least: a) a Mg-alcoholate complex of formula (I) b) an aluminum compound of formula (II); and c) a vanadium compound and a titanium compound having a molar ratio (V:Ti) from 10:90 to 90:10; and 2) one or more organometallic cocatalvsts of formula (III). The linear low density polyethylene shows an improved comonomer composition distribution Formulas (I), (II), and (III) are described herein.

Abstract: Described is a cyclobutene polymer comprising: monomeric units of cyclobutene, said cyclobutene having at least one fused ring system substituted thereon, said polymer comprising not more than 10 mol percent ring-opened units of said cyclobutene; and said polymer having a molecular weight of at least 1,000; said polymer optionally copolymerized with a comonomer to form a copolymer therewith. Compositions thereof and methods of making the same are also described.

Abstract: This invention provides a resin composition comprising a polyolefin-based polymer and an aliphatic polyester-based polymer, which has an excellent balance of impact resistance and rigidity and excellent properties, such as processability. The resin composition comprises a polyolefin-based polymer (A), an aliphatic polyester-based polymer (B), an elastomer (C), which has a melt flow rate (MFR), measured at 190° C. under a load of 21N, of 0.5 to 3.0 g/10 minutes, and an epoxy group-containing polyolefin-based polymer (D).

Abstract: The present invention provides a polymerization process utilizing a dual ansa-metallocene catalyst system. Polymers produced from the polymerization process are also provided, and these polymers have a reverse comonomer distribution, a non-bimodal molecular weight distribution, a ratio of Mw/Mn from about 3 to about 8, and a ratio of Mz/Mw from about 3 to about 6.

Abstract: An adhesive blend is described that can include a semi-crystalline copolymer of propylene and at least one comonomer selected from the group consisting of ethylene and at least one C4 to C20 ?-olefin, the copolymer having a weight average molecular weight (Mw) from about 15,000 to about 200,000; an melt index (MI) from about 7 dg/min to about 3000 dg/min as measured by ASTM D 1238 (B), and a (Mw/Mn) of approximately 2. Various production processes are also described. Also described are adhesive compositions and methods for making adhesive compositions having polymers or polymer blends with melt flow rates (MFRS) equal to and above 250 dg/min. at 230°C. Certain specific embodiments of the invention involve the use of a free radical initiator, e.g., a peroxide.

Abstract: The present invention relates to a process for the continuous transition between two different and compatible polymerisation catalysts.

Abstract: The invention relates to a continuous polymerization process for preparing a random ethylene interpolymer which comprises: (A) polymerizing ethylene, and an ?-olefin comonomer selected from propylene and/or 1-butene, and mixtures thereof, under continuous random polymerization conditions in the presence of single site catalyst system employing an ionic activator having cyclic ligands shielding a central charge bearing atom, at a temperature of 140° C. to 250° C. at a conversion of ethylene of 80 to 99% and a comonomer conversion of from at least 20%; and (B) devolatilizing the polymer to provide an ethylene copolymer having a density of from 0.85 to 0.92 g/cm3, an MI of from 0.01 to 100 g/10 min and an I21/I2 of from 30 to 400.

Abstract: Embodiments of the invention provide a class of mesophase separated butene/?-olefin block interpolymers with controlled block sequences. The butene/?-olefin interpolymers are characterized by an average block index, ABI, which is greater than zero and up to about 1.0 and a molecular weight distribution, Mw/Mn, greater than about 1.4. Preferably, the block index is from about 0.2 to about 1. In addition or alternatively, the block butene/?-olefin interpolymer is characterized by having at least one fraction obtained by Temperature Rising Elution Fractionation (‘TREF’), wherein the fraction has a block index greater than about 0.3 and up to about 1.0 and the butene/?-olefin interpolymer has a molecular weight distribution, Mw/Mn, greater than about 1.4.

Abstract: The present invention relates to compositions and processes of making polymers having a controlled molecular weight distribution. The molecular weight distribution is controlled, for example, by controlling the relative monomer concentrations during contact with a pre-catalyst and/or using a catalyst comprising a catalytic amount of a molecule having the structure: wherein M=group 2-8 metal, preferably group 4 as a neutral or charged moiety; Y=any substituent including fused rings; L=any ligating group, especially a pyridyl or pyridylamide; X=alkyl, aryl, substituted alkyl, H or hydride, halide, or other anionic moiety; y=an integer from 0 to the complete valence of M; R=alkyl, aryl, haloalkyl, haloaryl, hydrogen, etc; x=1-6, especially 2; Dashed line=optional bond, especially a weak bond; and X and (CR2)x may be tethered or part of a ring.

Abstract: Preparation of high-reactivity isobutene homo- or copolymers with a content of terminal vinylidene double bonds per polyisobutene chain end of at least 50 mol % and a polydispersity of preferably 1.05 to less than 3.5, by polymerizing isobutene or an isobutene-comprising monomer mixture in the presence of an aluminum trihalide-donor complex effective as a polymerization catalyst or of an alkylaluminum halide-donor complex, especially of an aluminum trichloride-donor complex, said complex comprising, as the donor, an organic compound with at least one ether function or a carboxylic ester function.