Akzo N.v.

Akzona Incorporated

Enka Ag

Klaus Gerlach

Wolfgang Lange

Nikolaus Mathes

Friedbert Wechs

Gerhard Wick

Hans-Jurgen Pitowski

Erich Kessler

Dieter Loh

Joachim Behnke

Wolfgang Rosener

Ewald Hohm

The invention concerns porous fibers and membranes, methods for their preparation and for their use. The fibers are characterized by a smooth porous surface and an apparent density of between about 10 to 90% of the true density of the polymeric starting material employed. The process involves the formation of a homogeneous mixture of at least two components, one of which is a meltable polymer and another liquid inert with respect to the polymer. The mixture formed must be of a binary type, in which there is a temperature range of complete miscibility and a range in which there is a miscibility gap. The mixture is extruded at a temperature above the separation temperature into a bath containing at least some of the inert liquid which is at a temperature below the separation temperature. Upon introduction of the mixture into the bath, the fiber structure of the product is fixed.

Porous fibers and membranes and methods for their preparation and use

Staple fibers made from crimped, in particular compression crimped, multicomponent filaments of the matrix/segment type, the cross section of which shows, in addition to the matrix, at least 6 peripheral wedge-shaped or lenticular segments, not completely covered by the matrix, are processed into a web, which is then mechanically bonded, preferably by needling. Subsequently, the fabric is subjected to a shrinkage process, by which its density is increased by more than 30%, themulticomponent fibers being completely or partly split up into their components. The difference in shrinkage between the components should be at least 10%. The liquids used for the shrinkage treatment are in particular organic liquids, such as methylene chloride, as well as other liquids producing a difference in shrinkage of at least 20%. The fabric is then impregnated with a solution of polyurethane on the basis of polyglycols, specifically polytetramethylene glycol, diisocyanates and low-molecular glycols as chain lengtheners, the jelling temperature of the solution being higher than the roomtemperature and higher than the temperature of the coagulation bath; the polyurethane is coagulated by cooling and/or treatment with a coagulation bath containing a non-solvent for polyurethane; then the fabric is washed, dried and ground on one or both sides. The suede-like product obtained combines great suppleness with high strength. It is an excellent material for making garments, such as coats, jackets or skirts, offering high wear comfort as well as high breathability.

Process for making suede-like sheet material

The invention concerns porous fibers and membranes, methods for their preparation and for their use. The fibers are characterized by a smooth porous surface and an apparent density of between about 10 and 90% of the true density of the polymeric starting material employed. The process involves the formation of a homogeneous mixture of at least two components, one of which is a meltable polymer and another liquid inert with respect to the polymer. The mixture formed must be of a binary type, in which there is a temperature range of complete miscibility and a range in which there is a miscibility gap. The mixture is extruded at a temperature above the separation temperature into a bath containing at least some of the inert liquid which is at a temperature below the separation temperature. Upon introduction of the mixture into the bath, the fiber structure of the product is fixed.

Methods for the preparation of porous fibers and membranes

Process and apparatus for enriching liquids with oxygen by means of a catalyst and a liquid which gives off oxygen under the effect of that catalyst. The process involves passing the oxygen-yielding liquid through a porous molding, in the pores of which the catalyst is incorporated in known manner, thereby giving off oxygen, the side of the porous molding which gives off a greater quantity of oxygen being in contact with the liquid to be enriched with oxygen. The oxygen-yielding liquid is passed through the porous molding under its own static pressure, or under the effect of the excess pressure built up in the container through the formation of oxygen. Preferred embodiments include use of 0.1 to 5% solution of hydrogen peroxide as the oxygen-yielding liquid; using manganese dioxide, Fe.sub.2 O.sub.3 or nickel oxide as the catalyst. The apparatus for carrying out the process includes a storage vessel containing the liquid which gives off oxygen under the effect of a catalyst, connecting means, and a porous molding connected thereby to the storage vessel and containing the catalyst, the molding being completely immersible in the liquid to be enriched with oxygen. Alternatively, the storage vessel and the porous molding can be dipped into the liquid to be enriched with oxygen, so that at least the entire molding is immersed.

Process and an apparatus for enriching liquids with oxygen

Process and apparatus for enriching liquids with oxygen by means of a catalyst and a liquid which gives off oxygen under the effect of that catalyst. The process involves passing the oxygen-yielding liquid through a porous molding, in the pores of which the catalyst is incorporated in known manner, thereby giving off oxygen, the side of the porous molding which gives off a greater quantity of oxygen being in contact with the liquid to be enriched with oxygen. The oxygen-yielding liquid is passed through the porous molding under its own static pressure, or under the effect of the excess pressure built up in the container through the formation of oxygen. Preferred embodiments include use of a 0.1 to 5% solution of hydrogen peroxide as the oxygen-yielding liquid; using ruthenium oxide or hydroxide as the catalyst. The apparatus for carrying out the process includes a storage vessel containing the liquid which gives off oxygen under the effect of a catalyst, connecting means, and a porous molding connected thereby to the storage vessel and containing the catalyst, the molding being completely immersible in the liquid to be enriched with oxygen. Alternatively, the storage vessel and the porous molding can be dipped into the liquid to be enriched with oxygen, so that at least the entire molding is immersed. Preferred embodiments include the porous molding being a tube having at least one empty space extending over its entire length, one end tightly sealed and the other end tightly connected to the storage vessel; the porous molding being a hollow body having an empty space with an internal diameter of at least 0.5 mm extending over its entire length; the porous molding being of polypropylene, MgO, Al.sub.2 O.sub.3 or clay; use of a metering pump for adjusting the supply of oxygen-yielding liquid; and provision of a vent connected to the porous molding.

A new and useful hydrophilic polyester fiber and process of making same are disclosed; the fiber has a stable pore system exhibiting a moisture pickup (regain) of at least about 2 percent by weight at 40.degree. C. and a relative humidity of 92%. Our experiments indicate that the proportion of moisture regain is attributable to capillary condensation in an amount of at least 25%. The hydrophilic properties are the result of a certain pore system within the fiber which enables capilliary condensation to occur significantly. The invention describes one way to accomplish this, namely by the addition of a predetermined amount of a suitable oxalato-complex to a suitable polyester mass. Most preferably, about 10% by weight K.sub.3 Al(C.sub.2 O.sub.4).sub.3 is added to the polyester mass. The fibers are produced by extruding a suitable polyester mass containing 1 to 20 percent by weight of a suitable oxalato complex to form a filament, drawing the filament, and hydrosetting the drawn filament at a suitable temperature, generally between about 90.degree. C. and about 170.degree. C., preferably between about 120.degree. C. and about 140.degree. C., under pressure, and in the presence of liquid water. The hydrophilic polyester produced by the novel process has the favorable moisture regain and many of the favorable texture qualities of cotton, together with the quick drying qualities of conventional polyester fiber.

Process for making hydrophilic polyester fiber

Fibrillatable multicomponent fibers of the matrix segment type and a process for production of fiber structures by splitting shrinkable, basically unset, multi-component fibers consisting of at least two incompatible components which in the fiber cross section are arranged in the form of a matrix and several segments, the latter accounting for about 20% to 80% of the total cross section. After having been processed into fiber structures such as staple fibers, yarns or fabrics, the multicomponent fibers are treated with a liquid or gaseous organic solvent, particularly chlorinated lower alkanes, to partially or completely split the segment filaments from the matrix component. Useful solvents are those which will reduce the zero-shrinkage temperature of the matrix or the segment polymer by at least 160.degree. C. and in which the polymer components constituting the fiber show different shrinkage behavior. Splitting may be further enhanced by the application of mechanical agitation, e.g. by ultrasonic waves. Fabrics made from the multicomponent fibers may be woven, knitted, non-woven, flocked and three-dimensional.

Fiber structures of split multicomponent fibers and process therefor

Production of a polyurethane embedding material from an aromatic diisocyanate in stoichiometric excess with a polyol mixture consisting essentially of castor oil and trimethylolpropane to first form a prepolymer containing unreacted isocyanate groups and being sufficiently flowable to permit coating onto membrane surfaces in all types of coating methods, and subsequently hardening the prepolymer by addition of a cross-linking agent consisting essentially of castor oil alone or another mixture of castor oil with trimethylolpropane in an amount sufficient to cross-link the prepolymer through at least a majority of its unreacted isocyanate groups. The products obtained in the invention are the embedding materials or the resulting hardened or cured embedded products or more simply 'bedded' final products which have excellent properties particularly adapted to the mounting of semipermeable membranes in dialysis equipment to give an improved and more useful construction.

Production of polyurethane embedding materials and use thereof

Staple fibers made from crimped, in particular compression crimped, multicomponent filaments of the matrix/segment type, the cross section of which shows, in addition to the matrix, at least 6 peripheral wedge-shaped or lenticular segments, not completely covered by the matrix, are processed into a web, which is then mechanically bonded, preferably by needling. Subsequently, the fabric is subjected to a shrinkage process, by which its density is increased by more than 30%, the multicomponent fibers being completely or partly split up into their components. The difference in shrinkage between the components should be at least 10%. The liquids used for the shrinkage treatment are in particular organic liquids, such as methylene chloride, as well as other liquids producing a difference in shrinkage of at least 20%. The fabric is then impregnated with a solution of polyurethane on the basis of polyglycols, specifically polytetramethylene glycol, diisocyanates and low-moleclar glycols as chain lengtheners, the jelling temperature of the solution being higher than the room temperature and higher than the temperature of the coagulation bath; the polyurethane is coagulated by cooling and/or treatment with a coagulation bath containing a non-solvent for polyurethane; then the fabric is washed, dried and ground on one or both sides. The suede-like product obtained combines great suppleness with high strength. It is an excellent material for making garments, such as coats, jackets or skirts, offering high wear comfort as well as high breathability.

Suede-like sheet material

An ultrafiltration membrane comprised of a linear polyurethane having a hydraulic permeability for water of about 50 to 500 1/m.sup.2 .multidot. h and a separation factor .alpha. of about 2.times.10.sup.-3 to 1.times.10.sup.-4, the permeability being based on determination with a membrane of a thickness of about 0.02 mm, a pressure differential of 1 bar and a temperature of 20.degree. C. and the separation factor .alpha. being established with a 2% oil-water emulsion at 25.degree. C. The membrane is particularly suited for operation of oil-water mixtures or emulsions.

Linear polyurethane ultrafilter and processes for use thereof

A molded polymer body with very fine, discrete, solid particles composed of a metal, metal compound or a mixture of the same incorporated within the molded body in a uniform pattern of distribution, substantially free of agglomerations, as obtained by a process of first impregnating the molded body with a bath solution of a metal compound and then gassing the molded body with a gaseous precipitating agent to precipitate the metal-containing particles. The products are especially useful in catalytic membranes, e.g. as used in artificial lungs or artificial kidneys.

Production of molded polymer body with metal inclusions

Hydrophilic polyester fiber and process for making same

Production of polyurethane embedding materials

A molded polymer body with very fine, discrete, solid particles composed of a metal, metal compound or a mixture of the same incorporated within the molded body in a uniform pattern of distribution, substantially free of agglomeration, as obtained by a process of first impregnating the molded body with a bath solution of a metal compound and then gassing the molded body with a gaseous precipitating agent to precipitate the metal-containing particles. The products are especially useful in catalytic membranes, e.g. as used in artificial lungs or artificial kidneys.

Molded body with inclusions

Fibrillatable multicomponent fibers of the matrix segment type and a process for production of fiber structures by splitting shrinkable, basically unset, multi-component fibers consisting of at least two incompatible components which in the fiber cross section are arranged in the form of a matrix and several segments, the latter accounting for about 20% to 80% of the total cross section. After having been processed into fiber structures such as staple fibers, yarns or fabrics, the multicomponent fibers are treated with a liquid or gaseous organic solvent, particularly chlorinated lower alkanes, to partially or completely split the segment filaments from the matrix component. Useful solvents are those which will reduce the zero-shrinkage temperature of the matrix or the segment polymer by at least 160.degree. C. and in which the polymer components constituting the fiber show different shrinkage behaviour. Splitting may be further enhanced by the application of mechanical agitation, e.g. by ultrasonic waves. Fabrics made from the multicomponent fibers may be woven, knitted, non-woven, flocked and three-dimensional.

Growing community of inventors

Obernau, Germany

Klaus Gerlach