Patent GB-616549-A (GB)
Title: Improvements in and relating to the treatment of nylon thread
IPC: D06M15/41
Filed: 1946-04-26
Abstract: The extensibility of cold-drawn nylon thread, cord, or like material, is reduced by impregnating the material with a soluble thermosetting resin or the components thereof, stretching the impregnated materials and then converting the resin into an insoluble form by heating the impregnated materials while they are stretched.  The treated material may be used in making reinforcement for pneumatic tyre covers or power transmission belts.  Impregnation with the soluble resin or components thereof is facilitated when the material is free from tension and it is preferably effected prior to stretching.  The stretching load may be nearly equal to the breaking load, but is preferably about half that load.  After the conversion of the resin has been completed the load is removed and the material is allowed to relax free from applied tension for several hours to allow it to assume stable dimensions.  In an example, a nylon cord is impregnated with a solution of an alcohol-soluble phenol-formaldehyde resin, obtained by mixing the two components in molar proportions of 1 to 0.8 using hydrochloric acid as catalyst, dissolving the product in ethyl alcohol and adding hexamethylene tetramine.  The impregnated nylon cord is stretched and then wound on bobbins under the stretching tension.  The wound material is heated in an oven at 105 DEG  C. to render the resin insoluble.  The cord is then allowed to relax at room temperature for 72 hours.  Instead of phenolformaldehyde, there may be used urea-formaldehyde, or resorcinol - formaldehyde.  The cord may be made of polyhexamethylene adipamide.ALSO:The extensibility of cold-drawn nylon thread, cord, or like material, is reduced by impregnating the material with a soluble thermosetting resin or the components thereof, stretching the impregnated materials and then converting the resin into an insoluble form by heating the impregnated materials while they are stretched. The treated material may be used in making reinforcement for pneumatic tyre covers or power transmission belts.  Impregnation with the soluble resin or components thereof is facilitated when the material is free from tension and it is preferably effected prior to stretching.  The stretching load may be nearly equal to the breaking load, but is preferably about half that load.  After the conversion of the resin has been completed, the load is removed and the material is allowed to relax free from applied tension for several hours to allow it to assume stable dimensions.  In an example, a nylon cord is impregnated with a solution of an alcohol-soluble phenol-formaldehyde resin, obtained by mixing the two components in molar proportions of 1 to 0.8 using hydrochloric acid as catalyst, dissolving the product in ethyl alcohol and adding hexamethylene tetramine.  The impregnated nylon cord is stretched and then wound on bobbins under the stretching tension.  The wound material is heated in an oven at 150 DEG  C. to render the resin insoluble.  The cord is then allowed to relax at room temperature for 72 hours.  Instead of phenolformaldehyde, there may be used urea-formaldehyde, or resorcinol formaldehyde.  The cord may be made of polyhexamethylene adipamide.