Patent ID: 11920262
Assignee: MONTEFIBRE MAE TECHNOLOGIES S.R.L.
Field: Textile and paper machines (Mechanical engineering)
Classification: CPC D  C | IPC C  D

Claim 0:
1. A process for the production of a carbon fiber precursor comprising:
i) preparing an acid comonomer solution selected from the group consisting of itaconic acid and acrylic acid in water containing at least a stoichiometric quantity of ammonia with respect to the acid groups present, wherein the concentration of acid comonomer in water varies within the range of 3% to 50% by weight, the total quantity of water fed to a reactor ranging from 1 to 5% by weight with respect to a total weight of a mass charged into the reactor in step ii);
ii) feeding into the reactor, acrylonitrile or a mixture of acrylonitrile and a neutral vinyl comonomer, the acrylonitrile or two comonomers acrylonitrile/neutral vinyl comonomer being present in a weight ratio ranging from 95:5 to 99.5:0.5, an aqueous solution of ammonium salt of the acid comonomer prepared in step i), DMSO, 2-2′-azobisisobutyronitrile AIBN and dodecylmercaptan or octylmercaptan;
iii) keeping the mixture from step ii) under stirring at a temperature ranging from 50 to 80° C., for a time ranging from 12 to 15 hours;
iv) discharging the contents of the reactor into a tank kept at a temperature ranging from 35 to 40° C. to slow down or interrupt the reaction;
v) feeding the mixture obtained from step iv) to a thin-film evaporation system (TFE) operating at a temperature ranging from 40 to 80° C., and at a pressure ranging from 5 to 30 mbar abs;
vi) collecting a mixture of acrylonitrile, water and DMSO from a head of the TFE, said mixture being re-used in the preparation of a new reaction batch;
vii) collecting a polymer solution in DMSO from a bottom of the TFE, said solution being diluted with fresh DMSO to reach a concentration ranging from 15 to 25% by weight with respect to the total weight of the solution and obtaining a homogeneous solution;
viii) feeding the homogeneous solution obtained at the end of step vii) to a following spinning step or to a storage tank.