Method of solid and/or liquid wastes treatment from production of flat or capillary membranes and fibres of native or modified polyphenylene oxide

The invention relates to the treatment of solid or liquid wastes from the production of flat or capillary membranes and fibers from native or modified poly (2,6-dimethyl-1,4-phenylene oxide) -poly-phenylene oxide, into fibrous or flat structures.

Polyphenylene oxide is one of the special polymers. Its price is many times higher than the prices of conventional polymers, and therefore the use of waste from the preparation of flat or capillary membranes and fibers is particularly important from an economic and ecological point of view.

Native or modified polyphenylene oxide is used to prepare semipermeable membranes. The preparation of such membranes is described in the literature, from which Broens, L. et al., Desalination, 22, 1977, 205-219, Wijmans, JG et al., J. Polymer Sci., Polymer Phys. Ed., 23, 1985, 1941 - 1955, Schauer, J. et al., Proceedings of the 25th Symposium “Hornická Příbram in Science and Technology, Section V, pp. 34-38, Schauer, J. et al., Synthetic Polymeric Membranes , Why. 29th Microsymposium on Macromolecules Prague, July 7-10, 1986, W. de Gruyter, Berlin, N. York 1987, pp. 219 - 226 a čs. author's certificate No. 263672, according to which the production of polymeric membranes and fibers consists in the preparation of the spinning solution, its extrusion by special nozzles into the coagulation bath in a dry-wet or wet manner and drawing. The spinning solution consists of polyphenylene oxide or modified polyphenylene oxide in an amount of 5 to 20% by weight, a good solvent in an amount of 55 to 90% by weight, and a bad solvent in an amount of up to 25% by weight. Chlorinated hydrocarbons or toluene are used as good solvents, bad solvents are, for example, aliphatic alcohols. An aliphatic alcohol, preferably methanol or ethanol, is used as the coagulation bath. Cs. author's certificate no. 263672 does not belong to the published state of the art to the present invention.

In the preparation of membranes or fibers, liquid and solid polymer wastes are generated, such as residues of spinning solutions, polymer solutions after cleaning of production equipment, solid wastes such as beginnings and ends of spun fibers, uneven edges of flat membranes, flattened and closed ends of fibers, residues after potting and liquid and solid wastes after testing of fibers and solutions for their preparation.

Polyphenylene oxide with a molecular weight of 74,000 and higher is used for the preparation of polymeric membranes, without the addition of polystyrene. However, the waste contains residues of solvents, precipitants and other chemicals and cannot therefore be processed in the usual way into plastic products.

Due to the fact that the production of polymeric membranes and fibers from polyphenylene oxide is still in its infancy, methods for regeneration and treatment of waste are not yet known. This technical and economic disadvantage is solved by the present invention, according to which residual solutions and solid wastes are sorted by type. The solid wastes are cut into pieces up to a size of 2 cm and, after drying, are dissolved in chlorinated hydrocarbons or mixtures thereof into a solution with a concentration of 5 to 25% by weight and a viscosity of 1 to 15 Pa.s. Liquid wastes are also treated to this composition by the addition of polymer or solvents. To process this solution into porous fibers or flat membranes, the solution is prepared with the addition of a precipitant; aliphatic alcohols are preferably used as precipitants. The solution obtained is filtered through a sieve with a minimum number of meshes of 10,000 meshes / cm and a spinneret with apertures of 0,05 to 3 mm in diameter as a monofilament or multifilament in the form of a solid or hollow fiber. A nozzle in the shape of a longitudinal slit is used to obtain a flat membrane. It is spun in a dry-wet or wet manner into aliphatic alcohols or mixtures thereof with water and chlorinated solvents up to a content of 30% by weight.

Example 1. ^{* 12}

Solid residues of sulphonated polyphenylene oxide fibers or membranes with a sulfur content of 1% by weight are freed of coarse impurities and, if necessary, cut into pieces with a maximum size of 2 cm. It is dried at 80 DEG C. for 3 h and dissolved in chloroform-trichlorethylene-butanol in a weight ratio of 7: 7: 3 to a solution with a viscosity of

Passport. at 20 ° C. The solution is filtered through a 16 000 mesh / cm sieve² and spun with a nozzle

CS 268986 B1 in the form of an annulus with an outer diameter of 2.5 and an inner 0.5 mm in a dry-wet manner in a coagulation bath consisting of ethanol containing 8% by weight, water, 9% by weight, chloroform, 6% by weight, trichlorethylene and 3% by weight, butanol . The hollow porous fiber obtained has a fineness of 1100 dtex, a strength of 0.55 cN / dtex and an elongation of 47%. The permeability of distilled water is 80 l / m.h at a pressure difference of 0.1 MPa, the rejection of methylene blue is 40%.

Example 2.

λ To the residues of the spinning solutions, to the solutions after cleaning of the mixing device and after determination of the viscosities in the in-process control, the fiber wastes dried by the procedure described in Example 1 are added. C. The fiber is prepared by wet spinning with a nozzle with 100 holes of 0.15 mm diameter into an ethanol coagulation bath. Towing speed is 15 m / min, drawing ratio 2. The fiber obtained has a fineness of 1200 dtex, a strength of 1.5 cN / dtex and an elongation of 50. Example 3.

Residues of spinning solutions and solutions after cleaning of production equipment are mixed with water in the ratio chloroform: water - 1: 4. The precipitated polyphenylene oxide villi are filtered 2 through a 100 mesh / cm sieve and dried in a vacuum oven or in an oven with air circulation and extraction into a fume hood to a moisture content of 0.25% by weight. The pieces are cut to a maximum size of 2 cm and dissolved in trichlorethylene to a solution with a viscosity of 6 Pa.s at 20 ° C. After filtration through a 12,000 mesh / cm sieve, the solution was wet-spun with a 0.3 mm diameter nozzle through 0.3 mm of methanol with isopropanol in a weight ratio of 7: 3. The undrawn fiber is drawn at a temperature of 60 ° C to a drawing ratio of 2. The prepared fiber is cut into a 75 mm long staple and fixed loosely at a temperature of 230 ° C. The prepared · fixed cut has a fineness of 1.5 dtex, a strength of 1.2 cN / dtex and an elongation of 80%.

Example 4.

The solid residues of the fibers or membranes are dried and treated according to Example 1. A 15% strength by weight solution of chloroform-isopropanol in a weight ratio of 4: 1 is prepared. After filtration, the solution is spun in a dry-wet manner through a longitudinal slit 1.5 mm thick into a coagulation bath of methanol with 30% by weight of chloroform at a draw-off speed of 5 m / min. The prepared porous membrane has a thickness of 0.25 mm, and a permeability to distilled water 2 at a pressure of 0.3 MPa of 40 kg / m 2 .h.