Abstract: The invention concerns an improved method for making paper, which uses a branched polymer prepared in invert emulsion as the main retention agent, and bentonite as a secondary retention agent (dual type system). The two additions are separated by a step for shearing the fibrous suspension (or mass). The invention results in highly improved retention and also highly improved dewatering. Moreover, it enables the bentonite content in white water to be reduced.

Abstract: The invention relates to an improved paper production process according to which a cross-linked polymer prepared in reverse-phase emulsion and sheared before introduction into the fibrous mass is used as the main retention aid, and then bentonite is used as the secondary retention aid (a dual type system). The two additions are not separated by any mandatory stage for intense shearing of the fibrous suspension (or mass). The paper manufacturer can therefore be free from the constraints of shearing the pulp. A distinctly improved retention of the fines is obtained, and also a distinct improvement in drainage. In addition, the bentonite content in the white water is reduced. Lastly, excellent formation is maintained.

Abstract: The invention relates to a process of synthesis at low temperature of polymers of the PVA (polyvinylamine) type on the basis the monomer vinylformamide. The polymerization claimed for the invention begins at around 0° C., is initiated by an original combination of redox and azoic catalysts, and is conducted under more or less normal pressure. The polymerization is conducted in water and is followed by direct hydrolysis. A powdered cationic PVA of high molecular weight is thereby obtained. The process may also be conducted in an emulsion at an initiation temperature of around 15° C. Application of PVAs as flocculants and coagulants in the paper, water treatment, petroleum and parapetroleum, and, similar industries.

Abstract: The invention relates to an improved paper production process, according to which a branched polymer prepared in reverse phase emulsion is used as the main retention aid, and then bentonite is used as the secondary retention aid (a dual type system). The two additions are separated by a stage for shearing the fibrous suspension (or mass).

Abstract: This invention relates to a process for preparation of cationic polymers of high molecular weight based on salts of diallyl dialkyl ammonium, in the form of beads, by the method of reverse suspension polymerization.

Abstract: The invention relates to an improved paper production process, according to which a branched polymer prepared in reverse phase emulsion is used as the main retention aid, and then bentonite is used as the secondary retention aid (a dual type system). The two additions are separated by a stage for shearing the fibrous suspension (or mass).

Abstract: According to the present invention, a cross-linked polymer or copolymer formed by reverse phase emulsion polymerization from suitable water-soluble monomers or from mixtures of such monomers is used as a retention agent. The process according to the invention is characterized in that the cross-linked polymer is sheared before its introduction or injection into the suspension to be flocculated. This results in a distinct improvement in the retention, formation, drainage and other properties of the paper or paperboard sheet thus obtained, as a function of the shearing.

Abstract: Process for improving retention during the manufacture of paper, board or the like, which consists:first of all in adding to the fibrous suspension a first retaining agent formed by a cationic polymer of high molecular weight,then, optionally in shearing the flocs obtained,and finally, in adding to the suspension a second retaining agent of inorganic nature, characterized in that the second retaining agent is a kaolin pigment.

Abstract: A process for preparing stable emulsions of polyelectrolytes of high molecular weight as reverse emulsion, in which:the monomers are dissolved in an aqueous phase,an organic phase containing a surface-active agent is prepared,these two phases are mixed to obtain an emulsion of the water-in-oil (W/O) type,the monomers are polymerized,the emulsion is incorporated to obtain a water-in-oil (W/O) emulsion, so as to make the polyacrylamide obtained water-soluble, which consists in adding to the aqueous phase a soluble polymer of low molecular weight, of the same general chemical nature and of the same ionic nature as the polyelectrolyte of high molecular weight which is envisaged.Envisaged application: preparation of polyacrylamide for flocculation and/or thickening applications (urban and industrial water treatments, papermaking).

Abstract: Process for the manufacture of a paper or a cardboard having improved retention, in which a polyacrylamide and bentonite are added to the fibrous suspension, wherein in that the polyacrylamide is a branched polyacrylamide, which is easily soluble in water, and is introduced in the dissolved powder form at a concentration of 0.03 to 1.0 per thousand (0.03 to 1.0%) by weight of the dry weight of the fibrous suspension.