Method for preparing a regenerated cellulose fibre or yarn

Process for the manufacture of a regenerated cellulose yarn comprising spinning a solution of a cellulose derivative or cellulose derivative in the molten state through at least one die hole and regenerating the cellulose by treatment of the yarn obtained, comprising

• synthesizing a silylated derivative of the cellulose by reaction with a silylating agent,
• extracting the said silylated derivative of the cellulose from the synthesis reaction mixture,
• spinning said silylated cellulose derivative, dissolved or brought to the molten state, through at least one die hole,
• treating said yarn with a desilylating agent, in order to regenerate the cellulose and recover a siloxane and
• optionally regenerating the silylating agent from the siloxane recovered in the stage of regeneration of the cellulose, wherein the silylating agent corresponds to one of the following general formulae:
• in which:
• n is between 0 and 20 inclusive
• R1 which can be identical or different, represent linear or branched alkyl radicals comprising from 1 to 12 carbon atoms or aromatic radicals
• R2 which can be identical or different, represent linear or branched alkyl radicals comprising from 1 to 12 carbon atoms or aromatic radicals
• R represents an alkyl, aralkyl, aryl or alkylaryl radical or radicals of following general formulae:
• in which:
• R3, R4, R5, R7 and R8, which can be identical or different, represent the hydrogen atom or an alkyl group comprising from 1 to 4 carbon atoms,
• R6 represents an alkoxy group or an alkyl group comprising from 1 to 4 carbon atoms,
• X represents a radical of following formula (V):
• in which:
• U represents a hydrocarbonaceous radical, an NH radical or an oxygen or sulphur atom,
• T represents a hydrocarbonaceous radical or a sulphur or phosphorus atom,
• V represents an oxygen or sulphur atom or an NH radical, and
• T is other than U and than V.