Patent GB-611331-A (GB)
Title: Stabilized crimped fibres
IPC: D06M13/123
Filed: 1946-04-26
Abstract: Crimped cellulosic fibres are stabilized in the crimped condition by impregnation with glyoxal or a glyoxal-yielding polymer, before, concurrently with or after the crimping thereof, and thereafter heating the fibres to at least 100 DEG  C. in the absence of any other crimp setting reagent or oils or plasticizers and in the presence of an acidic catalyst to cure the glyoxal and to cause it to react with the cellulose.  Reaction with the cellulose sets up acetal cross-linkages, the resulting crimped fibres having wool-like properties.  The concentration of glyoxal or glyoxal-yielding polymer may be between 1 and 10 per cent, and preferably within the range 2-5 per cent.  The pH of the solution should be between 2 and 3.5, suitable catalysts being boric, acetic, sulphanilic, oxalic and formic acids, ammonium chloride, ammonium sulphite, ammonium dihydrogen phosphate, and the a -mono-halogenated fatty acids such as a -chlor-, a -bromo-a -iodoacetic acids.  Substances which assist in maintaining the pH within the range may also be added, for example, sorbitol may be used with boric acid.  The process is applicable to all types of crimped cellulosic continuous filaments and staple fibres, and particularly to regenerated cellulose fibres from viscose or other cellulose yielding material, regardless of the manner in which the crimp is imparted thereto.  It is applicable to "self-crimpable" fibres, single component and multiple component viscose fibres, and to fibres for instance such as those showing in cross-section a portion of thick skin and portion with thin skin or no skin at all.  The glyoxal or glyoxal-yielding polymer may be applied by passage of the fibres through an aqueous solution of the glyoxal containing the catalyst, or the glyoxal and the catalyst may be applied successively.  The crimped fibres may be spun into yarn without loss of crimp.  In an example a cotton pulp viscose is spun into a bath containing sulphuric acid, zinc sulphate and sodium sulphate, and the filaments stretched.  During the stretching they are treated with hot water and crimped by being allowed to fall limply into a receptacle.  The crimped filaments are passed through an aqueous bath containing by weight 1 per cent ammonium phosphate and 5 per cent glyoxal, dried and the glyoxal cured at 120 DEG  C. for 5 minutes.  Specifications 450,620, 455,022, 460,201, 534,273, 585,679, 586,598 and 586,637 are referred to.ALSO:Crimped cellulosic fibres are stabilized in the crimped condition by impregnation with glyoxal or a glyoxal-yielding polymer, before, concurrently with or after the crimping thereof, and thereafter heating the fibres to at least 100 DEG  C. in the absence of any other crimp-setting reagent or oils or plasticizers and in the presence of an acidic catalyst to cure the glyoxal and to cause it to react with the cellulose. Reaction with the cellulose sets up acetal crosslinkages, the resulting crimped fibres having wool-like properties.  The concentration of glyoxal or glyoxal-yielding polymer may be between 1 and 10 per cent, and preferably within the range 2-5 per cent.  The pH of the solution should be between 2 and 3.5, suitable catalysts being boric, acetic, sulphanilic, oxalic and formic acids, ammonium chloride, ammonium sulphite, ammonium dihydrogen phosphate, and the a -monohalogenated fatty acids such as a -chlor-, bromo- and a -iodoacetic acids.  Substances which assist in maintaining the pH within the range may also be added, for example, sorbitol may be used with boric acid.  The process is applicable to all types of crimped cellulosic continuous filaments and staple fibres, and particularly to regenerated cellulose fibres from viscose or other cellulose-yielding material, regardless of the manner in which the crimp is imparted thereto.  It is applicable to "self-crimpable" fibres, single component and multiple component viscose fibres, and to fibres for instance such as those showing in cross-section a portion of thick skin and a portion with thin skin or no skin at all. The glyoxal or glyoxal-yielding polymer may be applied by passage of the fibres through an aqueous solution of the glyoxal containing the catalyst, or the glyoxal and the catalyst may be applied successively.  The crimped fibres may be spun into yarn without loss of crimp.  In an example a cotton pulp viscose is spun into a bath containing sulphuric acid, zinc sulphate and sodium sulphate, and the filaments stretched.  During the stretching they are treated with hot water and crimped by being allowed to fall limply into a receptacle. The crimped filaments are passed through an aqueous bath containing by weight 1 per cent ammonium phosphate and 5 per cent glyoxal, dried and the glyoxal cured at 120 DEG  C. for 5 minutes.  Specifications 450,620, 455,022, 460,201, 534,273, 585,679, 586,598 and 586,637 are referred to.