| 摘要 |
<p>1442033 Polyamides E I DU PONT DE NEMOURS & CO 16 Jan 1974 [17 Jan 1973] 01941/74 Heading C3R A continuous process for preparing a polyamide filament of uniform dyeability and relative viscosity from an aqueous solution of a polyamide-forming salt of a diamine and a dicarboxylic acid together with an excess of either the diamine or the acid comprises (a) heating the solution to concentrate it by evaporation, (b) polymerizing the solution at amidation temperatures and pressures, (c) passing the molten polyamide to a finisher where it is further polymerized and water removed, and (d) thence passing it through a transfer line to the manifold of a spinning machine where it is spun into a continuous filament; the dyeability level of the spun filament being controlled by increasing or decreasing the temperature of the evaporator whereby the number of amine ends in the polymer is increased or decreased so as to restore the pressure differential between two points in the transfer line to within a predetermined range of values. In an Example 51 wt. per cent aqueous nylon 66 salt at pH 7À2 from tank 2 is mixed with 100 lbs. adipic acid/8000 gallons in tank 8 and processed at 114‹ C. and 4 p.s.i.g. in evaporator 20, 245‹ C. and 250 p.s.i.g. in polymerizer 26 and 282‹C. and 2À4 p.s.i.g. in finisher 32 where the throughput is 4200 lbs./hr. and residence 7 minutes. Pressure is recorded at points 42 and 44 in the line to the spinning manifold and to maintain the differential within 7-5 p.s.i.g. of 1000 p.s.i.g. seven 0À05‹ C. reductions of temperature in evaporator 20 are effected between the 9th and 48th hour of operation.</p> |
