Patent GB-689582-A (GB)
Title: Improvements in the production of filaments and strings from collagen
Inventor: BRAUN BERND
IPC: A63B51/02
Filed: 1950-03-17
Abstract: Collagen filaments or strings, particularly for use as surgical sutures, musical instrument strings, tennis racquet strings, and textile threads, are obtained by subjecting animal tendons, without any previous swelling by chemicals, to a mechanical separation into fibres in the presence of a large excess of cold water, and then freeing the fibrous material from much of the unabsorbed water, adding acid to adjust the pH of the material to a value in the range 2.5-4,5 and to bring the mass into a highly swollen condition, converting the swollen mass into firm solid strips, e.g. by pouring, casting, or spreading and then drying, and finally twisting the strips into filamentary form.  The animal tendons may be converted into fibres by means of edge-runner mills, defibring machines, or cross-beaters.  The fibre suspension coming from the mill is concentrated by removal of water, e.g. by means of strainers, filter presses, or centrifuges. Hydrochloric acid may be used for the acidification.  Uniform treatment may be ensured by working the material in a kneader, mixer, or other agitating machine.  The swollen mass may be homogenized by rolling or by pressing through nozzles or perforated plates.  The mass may be diluted with water or an aqueous solution until it has a solid content of 0.5-1.0 per cent. Disinfectants, plasticizers, oil emulsions, or tanning agents may be incorporated.  The mass may be de-aerated and then formed into film strips by casting on to a band or other support. The films are dried and then stripped, and cut, if necessary, to the desired width.  The strips are moistened and then twisted to form the filaments or strings.  The water used for moistening the strips may contain tanning agents, disinfectants, e.g. iodine and iodine compounds, reducing agents, alcohols for inhibiting swelling, or basic substances for counteracting the acid swelling. Several strips may be twisted together to form a single filament. The drying may be effected under tension to improve the strength of the filaments. Finished untanned filaments may be treated with tanning agents, preferably those which may be applied in an inactive form and which can subsequently be caused to exert their tanning effect by adjustment of the pH or by reduction, as in the case of chromates.ALSO:Collagen filaments or strings, particularly suitable for use as surgical sutures, are obtained by subjecting animal tendons, without any previous swelling by chemicals, to a mechanical separation into fibres in the presence of a large excess of cold water, and then freeing the fibrous material from much of the unabsorbed water, adding acid to adjust the pH to 2.5-4.5 and to bring the mass into a highly swollen state, converting the swollen mass into firm solid strips, e.g. by casting and drying, and finally twisting the strips into filamentary form. Disinfectants, plasticizers, oil emulsions, or tanning agents may be incorporated in the swollen mass.  After formation by casting on a band or other support and drying, the strips may be cut, if necessary, to the desired width.  Several strips may be twisted together to form a single thread.  The thread or suture may be treated with tanning agents, e.g. a chromate.