Basf Aktiengesellschaft

Basf Se Corporation

Thomas Muehlenbernd

Gernot Koehler

Norbert Hasenbein

Christian Jehn-Rendu

Hubert Meixner

Lothar Schlemmer

Christopher Alan Gray

Luis Miguel Sanchez Cerro

Antonius Moormann-Schmitz

Bernd Lothar Marczinke

Hans-Joachim Haehnle

Roger G Klimesch

Juergen Kerth

Johannes Schlag

Ingolf Hennig

Martin Ruebenacker

Harald Schwager

Hans-Joachim Mueller

Heinz Vogt

Norbert Schall

Ellen Krueger

Ernst Fischer

Process for the Manufacture of Paper and Paperboard The present invention relates to a process of making paper or paperboard in which a cellulosic thin stock is provided and subjected to one or more shear stages and then drained and a moving screen to form a sheet which is dried, wherein the process employs a retention system which is applied to the thin stock, said retention system comprising as components i) a blend of different cationic polymers and ii) a microparticulate material, in which the blend of cationic polymers comprises, a) a cationic polymer having a charge density of from 0.5 and below 3 mEq per gram and a molar mass of greater than 700,000 Da, which cationic polymer is selected from polymers containing vinyl amine units and polyethylenimine, b) a cationic polymer having a charge density of below 3 mEq per gram and an intrinsic viscosity of at least 3 dl/g, wherein one of the components of the retention system is dosed into the thin stock after the final shearing stage and the other is dosed into the thin stock before the final shearing stage.

Process for the manufacture of paper and paperboard

The present invention relates to a process of making paper or paperboard in which a cellulosic thin stock is provided and subjected to one or more shear stages and then drained and a moving screen to form a sheet which is dried, wherein the process employs a retention system which is applied to the thin stock, said retention system comprising as components i) a blend of different cationic polymers and ii) a microparticulate material, in which the blend of cationic polymers comprises, a) a cationic polymer having a charge density of at least 3 mEq per gram and a molar mass of greater than 700,000 Da, b) a cationic polymer having a charge density of below 3 mEq per gram and an intrinsic viscosity of at least 3 dl/g, wherein one of the components of the retention system is dosed into the thin stock after the final shearing stage and the other is dosed into the thin stock before the final shearing stage.

Process for the production of paper, board and cardboard having high dry strength by addition of

Method for increasing the dry strength of paper, paperboard, and cardboard

A copolymer of (a) from 96 to 99.6% molar of ethylene and (b) from 0.4 to 4% molar of a C,-C,-alkenoic acid or an ester thereof having not more than 14 carbon atoms or a mixture of these monomers, which copolymer may be prepared by polymerization in a continuously operated tubular reactor under a pressure of from 500 to 5,000 bar and at elevated temperature in the presence of free-radical initiators by feeding a mixture of the said reactants to the inlet port of the reactor only, restricting the temperature in a first reaction zone to approximately 240&deg; C. and, after the temperature has dropped by from 5&deg;to 20&deg; C., metering further initiator to the beginning of a second reaction zone and completing the reaction at a temperature of up to 300&deg; C.

Copolymer of (a) ethylene and (b) and alkenoic acid or a derivative thereof a mixture of said monomers

Propylene copolymers grafted with .alpha.,.beta.-ethylenically unsaturated carboxylic acids or derivatives and containing up to 35% by weight of other C.sub.2 - to C.sub.10 -alk-1-enes are obtainable by reacting the monomer to be grafted with a propylene copolymer at from 1 to 500 bar, where, in the absence of a free-radical initiator, from 0.01 to 1.0% by weight, based on the propylene copolymer, of the monomer to be grafted are admixed with the molten propylene copolymer, and the grafting reaction is carried out at from 210.degree. to 350.degree. C. The propylene copolymers according to the invention can be converted into crosslinked or crosslinkable propylene copolymers by admixing organic crosslinking agents.

Grafted, crosslinked and crosslinkable

Novel ethylene homopolymers and ethylene copolymers which are suitable for film production and have a density from 925 to 940 kg /m.sup.3, a melt flow index (MFI) of &lt;1 g/10 min at 190.degree. C. and at an applied force of 2.16 kp can be prepared by free radical polymerization of the monomers at from 500 to 5000 bar and reaction temperatures T of from 40.degree. to 320.degree. C. by means of an initiator with virtually complete exclusion of oxygen in at least n=3 polymerization stages. In the first stage, the total amount or the predominant part of the monomers is subjected to the polymerization by means of part of the required initiator until the polymerization virtually comes to a stop. A further part of the initiator and, if required, of the monomers is then added to the mixture cooled to 20.degree.-60.degree. C. This process is repeated in the subsequent stages until the n th stage, at least the initiators used in the n th stage having a half-life temperature of from 90.degree. to 260.degree. C., and that the maximum reaction temperature T.sub.max being 270.degree. C. or higher, at least in the n th stage.

Ethylene homopolymers and ethylene copolymers and a process for their

Carboxylic acids of the general formula I ##STR1## where R.sup.1, R.sup.2 and R.sup.3 independently of one another are each hydrogen, hydroxyl, carboxyl or C.sub.1 -C.sub.6 -alkyl and x, y and z independently of one another are each 0 or an integer of from 1 to 6, and/or their anhydrides can permanently suppress the formation of water trees in electrical medium and high voltage cables which contain electrically insulating and/or electrically semiconductive layers based on ethylene homopolymers and/or copolymers, even when the relevant layers contain water-soluble basic salts. Accordingly, polymeric mixtures based on ethylene homopolymers and/or copolymers which contain the above-mentioned carboxylic acids I and/or their anhydrides are very useful for the production of electrically insulating and electrically semiconductive layers as used in electrical medium and high voltage cables.

Electrical medium and high voltage cable with a cable sheath having high

Ionically crosslinked ethylene copolymers are prepared by reacting the corresponding ethylene copolymer in a mixing zone of a twin-screw extruder with a solid metal compound and subsequently pumping in water, and are used as adhesion promoters, laminating films, injection molded articles or cable sheathing.

Preparation of homogeneous ionically crosslinked ethylene copolymer in

Ionically crosslinked ethylene copolymers prepared by mixing a carboxyl-containing copolymer with an aqueous metal salt solution in the reaction zone of a twin-screw extruder and transferring the product to a devolatilization zone, and are used as adhesion promoters, injection molded articles or laminating films.

Ionic crosslinking of an ethylene copolymer in twin-screw extruder

Ionically crosslinked ethylene coolymers prepared by neutralizing the corresponding ethylene copolymers with the addition of an ionomer to a feed zone of an extruder of an ethylene high pressure polymerization system are used for film production, for cable sheathing and as adhesion promoters.

Preparation of ionically crosslinked ethylene copolymers, ionically

A high molecular weight ethylene copolymer is prepared by high-pressure copolymerization of ethylene with an .alpha.,.beta.-ethylenically unsaturated carboxylic acid, carboxylic anhydride or a derivative thereof in the presence of a tertiary organic monoamine, preferably from 10 to 100 mol % thereof, based on the unsaturated carboxylic acid used, and can be used for preparing adhesion promoters and cable sheathing.

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Heidelberg, Germany

Thomas Muehlenbernd