Abstract: Method for purifying a solution of at least one plastic in a solvent, the said solution comprising insolubles, whereby the solution is purified using a centrifugal settler.

Abstract: Method for recovering a polymer from a liquid medium (1) substantially containing the polymer and a solvent for the latter, wherein: (a) this liquid medium (1) is injected into a reactor (2) containing a stirred substantially monophase liquid mixture comprising a major fraction by weight of a non-solvent and a minor fraction by weight of a solvent, the mixture having a composition and temperature such that the polymer precipitates therefrom progressively; (b) the polymer is recovered in the form of particles in suspension (5) in a liquid rich in non-solvent; (c) the polymer particles (9) are separated from the liquid.

Abstract: Method for recovering a polymer from a liquid medium (1) substantially containing the polymer and a solvent for the latter, wherein: (a) this liquid medium (1) is injected into a reactor (2) containing a stirred substantially monophase liquid mixture comprising a major fraction by weight of a non-solvent and a minor fraction by weight of a solvent, the mixture having a composition and temperature such that the polymer precipitates therefrom progressively; (b) the polymer is recovered in the form of particles in suspension (5) in a liquid rich in non-solvent; (c) the polymer particles (9) are separated from the liquid.

Abstract: Process for the solvent treatment of a plastic, by dissolving the plastic with a solvent and with at least one phase separation agent compatible with the solvent to form a solution, precipitating the plastic by contacting the solution with at least one non-solvent so as to obtain a solvent/non solvent mixture containing precipitated plastic particles, and substantially eliminating the solvent from the mixture and recovering solid plastic particles. After dissolution but before substantially eliminating the solvent a stripping takes place during which at least a substantial portion of the PSA is removed from the solution or from the mixture using a stripping composition.

Abstract: Method for purifying a solution of at least one plastic in a solvent, the said solution comprising insolubles, whereby the solution is purified using a centrifugal settler.

Abstract: Process for the recovery of a polymer in solution Process for the recovery of a polymer in solution in a solvent, the combined material forming a homogeneous medium, according to which: a) a nonsolvent is added to the homogeneous medium so as to render it heterogeneous; b) the heterogeneous medium is subjected to shearing and to a supply of thermal energy sufficient to evaporate the solvent and nonsolvent and to provide polymer particles; c) the polymer particles are recovered.

Abstract: Process for the solvent treatment of a plastic, comprising: (a) dissolving the plastic by contacting it with a solvent and with at least one phase separation agent (PSA) compatible with the solvent and capable of improving the dissolution of the plastic by the solvent; (b) precipitating the plastic by contacting the solution with at least one nonsolvent so as to obtain a solvent/non solvent mixture containing precipitated plastic particles; and (c) substantially eliminating the solvent from the mixture and recovering solid plastic particles, wherein after step (a) but before step (c), a stripping step (d) takes place during which at least a substantial portion of the PSA is removed from the solution or from the mixture, said stripping step (d) using a stripping composition which includes solvent in an amount sufficient to replace the evaporated one and to keep the polymer concentration in the solution or in the mixture practically unaffected.

Abstract: Process for recycling an article based on at least one vinyl chloride or vinylidene chloride polymer, according to which: (a) the article is cut up into fragments with a mean size of 1 cm to 50 cm in the case where it would exceed these sizes; (b) the article fragments are brought into contact with an azeotropic or quasiazeotropic mixture of water and of a solvent capable of dissolving the polymer, at a temperature of at least 120° C.; (c) the polymer dissolved in the solvent is precipitated by a reduction in pressure and by injection of steam into the solution thus obtained, which additionally results in the entrainment of the solvent-water azeotrope and thus leaves a mixture remaining which is essentially composed of water and of solid polymer particles; (d) the polymer particles are collected.

Abstract: Process for recycling a plastic, according to which the plastic is brought into contact with a solvent capable of dissolving the same and the plastic dissolved in the solvent is precipitated using a non-solvent in the presence of a phase-separating agent, in which the phase-separating agent is compatible with the solvent and incompatible with the non-solvent, and is also present when the plastic is brought into contact with the solvent, and improves the dissolution of the plastic by the solvent.

Abstract: Process for recovering a polymer in solution in a solvent, the whole forming a homogeneous medium, according to which: (a) a non-solvent is added to the homogeneous medium so as to make it heterogeneous, (b) the heterogeneous medium is converted into droplets by atomization, (c) the droplets are placed in contact with a gas that vaporizes the solvent, (d) the polymer is recovered in the form of particles.

Abstract: Process for recycling a plastic, according to which the plastic is brought into contact with a solvent capable of dissolving the same and the plastic dissolved in the solvent is precipitated using a non-solvent in the presence of a phase-separating agent, in which the phase-separating agent is compatible with the solvent and incompatible with the non-solvent, and is also present when the plastic is brought into contact with the solvent, and improves the dissolution of the plastic by the solvent.

Abstract: Process for recycling an article based on at least one vinyl chloride polymer, in which: (a) the article is shredded into fragments having an average dimension of 1 cm to 50 cm, should it exceed these dimensions; (b) the fragments of the article, which are substantially dry, are brought into contact with a substantially anhydrous solvent capable of dissolving the vinyl chloride polymer, forming an azeotrope with water; (c) the polymer dissolved in the solvent is precipitated by injecting steam in the solution thus obtained, which moreover leads to the stripping of the water-solvent azeotrope and so leaves behind a mixture essentially consisting of water and of solid polymer particles; (d) the polymer particles are recovered.

Abstract: Process for the treatment of ground polyolefin material originating from scrap dairy product containers with at least one agent chosen from hydrogen peroxide, steam and sodium hydroxide in a quantity which is effective for deodorizing the polyolefin. Ground material obtained by this process and exhibiting an imperceptible level of residual odour of aged milk. Use of the deodorized ground material obtained by this process for the production of shaped objects.

Abstract: Process for separating the constituents of a multilayer material including at least one layer of a base plastic (A) and a layer of a plastic (B) which are separated by a layer of adhesive plastic (C), in which: (1) the material is heated to a temperature T1 between the crystallization temperature of the plastic B (Tc) and Tc--20.degree. C., (2) the material is next shredded by being subjected to shearing, at approximately the same temperature, so as to produce delamination and thus to convert the material into particles of small dimensions of two types, some (X) consisting essentially of base plastic (A) and others (Y) consisting essentially of plastic B and of adhesive plastic (C), and (3) the particles X and Y are subsequently separated by electrostatic separation.