Method and device for the production of molded bodies
A method for the production of molded bodies from a base substance, wherein the base substance is mixed with a solution for producing a molding solution, and the solution subsequently is at least partially removed from the mixture, and the molding solution is fed to a unit for molding, wherein the molding solution is diluted before molding.
1. A method for producing fibers from a renewable base substance comprising the steps of:
(a) a first dilution step comprising mixing a renewable base substance and a solvent in the presence of heat to intensify comixing and evaporate a portion of the solvent to produce a first spinning solution;
(b) a viscosity lowering step consisting of diluting the first spinning solution from step (a) with the same solvent from step (a) to form a second diluted spinning solution having a viscosity below that of the first spinning solution and suitable for spinning;
(c) spinning the second diluted spinning solution with the lower viscosity to produce fibers of the renewable base substance; and
wherein a tertiary amine oxide is used as the solvent in step (a) and step (b).
2. A method according to claim 1 , wherein the solvent comprises amine oxide monohydrate.
3. A method according to claim 2 , wherein the first spinning solution is conveyed from a buffer vessel under pressure by means of a first volumetric pump, and the amine oxide monohydrate is metered into the first spinning solution with a second volumetric pump.
4. A method according to claim 3 , wherein the two volumetric conveying pumps are matched to one another such that a spinning solution with a concentration of 4 to 14% of base substance to be dissolved in amine oxide monohydrate is produced.
5. A method according to claim 1 , wherein the second diluted spinning solution is treated in a mixer.
6. A method according to claim 1 , wherein steps (b) and (c) are carried out at a temperature of 80 to 120° C.
7. A method according to claim 1 , wherein the second diluted spinning solution is stored in a buffer vessel prior to spinning.
8. A method according to claim 7 , wherein the second diluted spinning solution is introduced into the buffer vessel in a bubble-free state.