Cellulose filament yarn production

摘要

The precipitation bath is used for the production of cellulose filament yarns, in a dry-wet extrusion process. The precipitation bath has a laminar upwards flow in the zone surrounding the spinning funnel. The main portion of the precipitation bath flows in on the entry cross-section of the spinning funnel in a zone which is 3-20 mm below the bath surface level and, after contact with the filaments along a stretch of 30-130 mm, it is partially separated from the filaments. Surplus precipitation bath liquid passes out of the spinning funnel zone through an overflow. The overflow and the separated main portion of the fluid is returned to the zone round the spinning funnel. In an Independent claim the apparatus has a spinning funnel (2) with a total length (SL) of 30-100 mm. The ratio of the funnel entry and outlet cross-sections A1:A2 is 5:1 to 80:1. A feed opening (4) is at the base of the spinning box (1), and an overflow barrier (5) for the precipitation bath (3) is at a level of 5-15 mm over the upper edge of the spinning funnel. Preferred Features:- The precipitation bath liquid, before entry into the zone round the spinning funnel, has a flow speed which is faster through a filled body stretch than in an empty stretch, with the flows aligned vertically upwards and downwards. The liquid flow speed is accelerated by 5-80 times in the spinning funnel. On leaving the spinning funnel, the filaments are deflected at a tangent or at a small angle of up to 30 deg , out of the precipitation bath liquid flow. The length (SL) of the spinning funnel (2) is pref. 40-60 mm, and the funnel entry-outlet ratio A1:A2 is pref. 10:1 to 30:1. A flow channel (14) is in front of the feed opening (4), with a section filled with bodies (20) and an empty section (21) at the outflow side. A lower container (10) holds the precipitation bath overflow from the spinning funnel (2) and the spinning box (1), and is connected to the feed opening (4) through a pump (17). The air gap (SV), between the spinning jet (6) and the surface of the spinning bath, has a width of 10-50 mm. The spinning funnel (2) is of an elastic material.