Abstract: The invention relates to a process for producing a strengthened fiber assembly containing cellulosic fibers with the cellulose being present in the crystalline structure of cellulose II, by contacting the fiber assembly with an aqueous solution of N-methylmorpholine-N-oxide (NMMO) at elevated temperature and subsequently washing the fiber assembly, characterized in that contacting is effected in a manner that from the relation-947+0.30.times.log.sub.(10) t+0.046.times.T-3.53.times.C +645.times.log.sub.(10) Cwherein t indicates the time in minutes during which the fiber assembly is contacted with the aqueous NMMO solution, T indicates the temperature of the aqueous NMMO solution in .degree.C. and C is the concentration of NMMO in % by mass, based on the aqueous NMMO solution, a number in the range of 0.30 to 1.70 results with the proviso that the temperature T is smaller than 130.degree. C. and the concentration C ranges between 70 and 84 % by mass.

Abstract: To prepare cellulose mouldings, a solution of cellulose in a tertiary amine-oxide is moulded in a hot state and the moulded solution is introduced into a precipitation bath in order to precipitate the contained cellulose, wherein the hot moulded solution is cooled before introduction into the precipitation bath. Cooling occurs immediately after the moulding process and preferably consists of blowing air horizontally on to the cellulose moulding. The process according to the invention allows spinning of the cellulose solution with a high fiber density without the spun fibers sticking together after emerging from the spinneret. In spite of the high fiber density, it furthermore allows the use of a long air gap between the spinneret and the precipitation bath, by which means sufficient time is generated in the spinning process to affect the textile properties of the fibers by drawing at the die (FIG. 1).

Abstract: Apparatus for the preparation of cellulose fibers from a solution of cellulose in a tertiary amine oxide includes a spinneret having a multiplicity of spinning holes arranged essentially in a ring-shape. An inlet for cooling gas is positioned in the center of the ring-shape arrangement of the spinning holes and immediately downstream of the spinning holes. The inlet comprises a tube having a baffle plate at one end.

Abstract: To prepare cellulose fibres, a solution of cellulose in a tertiary amine-oxide is shaped in hot condition to give filaments, the filaments are cooled and then introduced into a precipitation bath in order to precipitate the dissolved cellulose, whereby the shaped solution is exposed to an essentially laminar gas stream (FIG. 2a) for cooling before introduction into the precipitation bath.

Abstract: To prepare cellulose mouldings, a solution of cellulose in a tertiary amine-oxide is moulded in a hot state and the moulded solution is introduced into a precipitation bath in order to precipitate the contained cellulose, wherein the hot moulded solution is cooled before introduction into the precipitation bath. Cooling occurs immediately after the moulding process and preferably consists of blowing air horizontally on to the cellulose moulding. The process according to the invention allows spinning of the cellulose solution with a high fibre density without the spun fibres sticking together after emerging from the spinneret. In spite of the high fibre density, it furthermore allows the use of a long air gap between the spinneret and the precipitation bath, by which means sufficient time is generated in the spinning process to affect the textile properties of the fibres by drawing at the die.

Abstract: Disclosed is a process for producing cellulose fibers having a decreased tendency to fibrillate. The process comprises the steps of extruding a solution of cellulose in a tertiary amine-oxide through spinning holes of a spinneret to form cellulose filaments, conducting the extruded cellulose filaments across an air gap of greater than 30 mm, and introducing the cellulose filaments into a precipitation bath. The process is carried out in a way that the mathematical expression 51.4+0.033.times.D+1937.times.M.sup.2 -7.18.times.T-0.094.times.L-2.50.times.F+0.045.times.F.sup.2, does not exceed the number 10. In the mathematical expression, D is the spinning hole diameter in .mu.m, M is the dope output per hole in g/min, T is the titer of the individual filament in dtex, L is the length of the air gap in mm and F is the humidity of the air in the air gap in g of water/kg of air.

Abstract: There is disclosed a process for preparing solutions of cellulose in aqueous tertiary amine oxides from a suspension of cellulose in an aqueous solution of the tertiary amine oxide by supplying heat at a reduced pressure. The suspension is transported over a heating surface, spread in layers or coats, until a homogenous solution of the cellulose has formed, which has a viscosity of between 50 and 15,000 Pas.s. Feeding of the suspension and drawing-off of the homogenous solution are carried out continuously. The solutions are prepared in an indirectly heated evacuatable vessel provided with a stirring device. The vessel is designed as a cylindrical container including a centrically mounted stirring shaft having agitators joined thereto, the radial distance of the agitators from the internal wall of the container being 20 mm at the most. There are provided an intake for the cellulose suspension in the upper part of the container and an outlet for the homogenous cellulose solution in its lower end.

Abstract: A cellulosic solution in a amine oxide and water is forced through an elongated orifice passage having a minimum length of 1000 /.mu.m and a minimum diameter along the length which is up to 150 /.mu.m so that fiber characteristics are imparted to the emerging strand which passes through an air gap of at the most 35 mm in length into the coagulating solution.

Abstract: Shaped cellulosic bodies and especially cellulosic fibers or filaments are produced by precipitating cellulose from a solution containing cellulose and NMMO. To allow elevated concentrations of NMMO in the precipitating bath without detriment to the properties of the fibers or filaments produced, the temperature of the precipitating bath is held at most at 0.degree. C.

Abstract: There is disclosed a process for preparing solutions of cellulose in aqueous tertiary amine oxides from a suspension of cellulose in an aqueous solution of the tertiary amine oxide by supplying heat at a reduced pressure. The suspension is transported over a heating surface, spread in layers or coats, until a homogenous solution of the cellulose has formed, which has a viscosity of between 50 and 15,000 Pas.s. Feeding of the suspension and drawing-off of the homogenous solution are carried out continuously. The solutions are prepared in an indirectly heated evacuatable vessel provided with a stirring device. The vessel is designed as a cylindrical container including a centrically mounted stirring shaft having agitators joined thereto, the radial distance of the agitators from the internal wall of the container being 20 mm at the most. There are provided an intake for the cellulose suspension in the upper part of the container and an outlet for the homogenous collulose solution in its lower end.