US 2990236 A
Description (OCR text may contain errors)
June 27, 1961 E. l. RISELEY 2,990,236
SPINNING PROCESS Filed March 18, 1958 2 Sheets-Sheet 1 I Ema fmw F/SH EV ATTORNEYS June 27, 1961 1, RISELEY 2,990,236
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ww mm ATTORNEYS Un ed Se ee *9" 2,990,236 p I S INNINGPROCE-SS Eric 'IvanRisel'ey,
a corporation of Great Britain v Filed Mar.'18, '1958, Ser. No.722,1-59 1 Claims p1iority,'application Great Britain 25, 1957 V i 5 Claims. (Cl. 18-54) This invention relates to an improved melt spinning process.
In themelt'spinning of high polymers to producefine filamentary "materials-of lessthan '3 denier per filament by extrusion through multi-holed spinnerets, the bundle of extruded filaments may be collected by winding them, for example, onto surface driven bobbins. Filamentary material made in this way has been found to be irregular with respect both to the overall denier of the bundle and also the denier of individual filaments produced substantially at the same instant of time. It is well known that these variations seriously affect the quality of the textile materials made from the filamentary material.
Certain of these denier variations cannot be attributed to such mechanical causes as the traverse mechanism and the winding-up unit and are therefore not easily overcome and so far they have defied attempts at correction. These variations are irregular in amplitude.
It is well known that as the extruded fine filaments leave the spinneret they cool down and eventually harden at a distance some inches below the spinneret face. In British patent specification No. 661,999 there is disclosed a process of spinning fine denier filament yarns from a melt of synthetic filament forming polymeric materials wherein a melt of said polymeric materials is extruded through a multi-hole spinneret into a stream of inert gas passing through a spinning cell and maintained at a temperature suflicient to cool said molten polymeric material to below its solidification temperature whereby to form simultaneously a plurality of fine denier filaments with the improvement which comprises collecting said filaments into a yarn and steadying said yarn as soon as said filaments solidify and become substantially non-tacky by means of convergence yarn guide.
According to my invention I provide an improvement in the process of British Patent No. 661,999 wherein the filaments after leaving the spinneret pass, under tension, over one or more guides located between the spinneret and the wind up means, the guide or guides being in the region wherein the filaments solidify and become substantially non-tacky, characterised in that the filaments in passing round the guide or guides are deflected through an angle of not less than 5 and not greater than 90.
Whilst the object of my invention may be attained by ensuring that the filaments in passing around the guides are deflected through angles within the range of 5 to 90 we prefer that the angle of deflection should be within the range of 30 to 60 as this range provides the mininum denier variability consistent with threadline stability.
Preferably the guide or guides comprise one or more low friction thread constraining surfaces. The yarn contacting surfaces of my guide may be of any suitable material and I have found that guides made from ceramics with surfaces of low coeflicient of friction and sand blasted matt-chromium plated metal are particularly satisfactory.
The guides of my invention may be of tubular construction and adapted to be cooled internally.
The guides may be fixed or capable of rotation by the moving filaments. I have found that light weight freely rotatable rollers are suitable and if fine circumferential grooves are cut around the roller the individual filaments Harrogate,'England, assignor to perial Chemical Industries Limited, London, England,
are, separated as they pass over the roller and are there oi g'uides'insuch a position that the birefringence of thefilament leaving the guidesis increased by about 20%- over the birefringence value obtained when the guide or guides are removed.
The attached drawings illustrate but do not linut the scope of my invention FIGU-RES l and. 2'are side elevations of a rigid guide ring and-FIGURE 3 a plan viewof said'ring.
FIGURE 4 shows the use of a plain idler roller as a deflecting guide and FIGURE 5 illustrates a grooved idler roll.
With reference to FIGURES 1, 2, and 3, extruded filaments 1 from a spinneret 2 pass individually through a number of guides 3 which are substantially equally spaced about the periphery of a rigid guide ring 4 to a convergence yarn guide 5 and to a wind up means 6 (schematically shown).
The guide ring 4 is arranged beneath the spinneret 2 in the region Where the filaments solidify and become non-tacky and the diameter of the guide ring is such that each filament is deflected through an angle (FIGURE 2) where 0 is greater than 5 and less than In FIGURE 4 the filaments are deflected around a free running idler roll 7, A" in diameter, mounted in a support 8. The idler roll may be conveniently made of sand blasted steel with a chromium plated skin.
FIGURE 5 illustrates a preferred type of free running idler roll 9 provided with fine circumferential grooves 10.
Table 1 illustrates the percentage coeflicient of variation of yarns comprising 48 filaments of polyethylene terephthalate of 1 and 2 denier per filament (drawn) when passed around an Alsimag (registered trademark) ceramic guide located so as to deflect the yarns through a range of angles of 0 to 60. The vertical distance below the spinneret for the 1 denier per filament yarn was 19 inches and for the 2 denier per filament yarn 26". Both yams were spun through 48 hole spinnerets, the spinning temperature was 290 C. and the wind-up speed 3000 ft./min. The denier per filament was altered by adjusting the speed of the gear pump.
In one version of my invention substantially equal fractions of a number of filaments coming from the spinneret each pass around a separate guide, said separate guides being equally spaced around the periphery of a rigid ring located between the spinneret and the wind-up means. I have found it preferable that the fraction of a number offilaments is not greater than one quarter.
What I claim is:
1. A melt spinning process for the production of fine denier filaments comprising extruding molten polymer through a multi-hole spinneret to form filaments, and passing the resultant filaments without material frictional drag about guide means located in the region where the filaments solidify and become substantially non-tacky to Patented June 27, 1961 moons-e A i 3 a wind-up means, characterized in that the filaments in passing around the guide means are deflected through an angle of not, less than 5" and not more than 90.
2. A process according to claim 1, wherein the fila-' ments are deflected through an angle not. less than 30" and not more than 60.
3'. A process, according to claim 2, wherein the guide means comprisesat, least one light weight freely rotabl'e roller.
4.. A process according to claim 3, wherein fine circum ferential grooves are cut into the surface of the roller in planes at. right angles to the axis of the roller.
5. In a melt spinning process for the production of fine ing the filaments fromthe spinneret without material frictional drag about the periphery of a guide ring located in the region where the filaments solidify and become substantially non-tacky, thereby deflecting each of the filaments through an angleof not, less than and not more than, and conducting the filaments to a wind-up References Cited in theme of this: patent UNITED STATES PATEN'IIS- 1,951,181 Battin Mar. 13, 1934 2',595,044 Zmatlik et a1. Apr. 29, 1952 2,624,934 Munson et al. Jan. 13 195.3,- 2,76Z,429 McCrosky Oct. 23, 1956 Sharp Sept. 16, 8