US2639214A - Process of forming thread - Google Patents

Description

y 1953 c. F. GRAM 2,639,214

PROCESS OF FORMING THREAD Filed Aug. :5, 1945 2 Sheets-Sheet 1 Fig. 2. E1; 5.

INVENTOR." CARL F GRAN May 19, 1953 c. F. GRAM 2,639,214

PROCESS OF FORMING THREAD Filed Aug. 3, 1945 2 Sheets-Sheet 2 INVENTOR. CARL E QHAM [#4 we y Patented May 19, 1953 PROCESS OF FORMING. THREAD Garl F. Grama-Bbwaytcn, Conn;, assignor-t'o-North American Rayon; Gorporation, New York N. 36., a corporation: of Delaware Application August3, 1945,.S'erialNo. 608555 L Claim 1? In the-productionof high tenacity rayon yarn such as is employed in the production of heavy duty tires used on aircraft, trucks, guncarriages and" the'like where severe service conditions are encountered, many important factors'enter into the method" of treating the yarn; One'of thesefactorsisthe rapidity with which'impur-itiescon-- tained in-such yarn, as-a result ofitsformation, can be removed from theindividual' filaments of which the yarn-is composed:

High tenacity viscose yarn, for example, is ordinarily producedby extruding-- a Viscose spinningsolution into 'an-acid spin bathunder conditionstoform a thread; withdrawing the-thread thus'formed fromthebath before complete re-' generation-citric cellulose content ofthe-viscose has been completed, passing the incompletely regenerated thread:through a hot water'bath under stretching to accelerate regeneration; and then collecting: it on a -per-forated bobbin upon whi-ch: complete'regeneration of the cellulose takes-place anctupon: which it-is: subsequently subjected toi after-treatment such as-washing to remove acidti and desulphurizing to: removessulphur. therefrom. Eurther after treatmenti may include additional was-hing, bleaching, sizing and: like steps. com.- monly; practiced; in the rayon. and. allied textile: arts;

Onetfeaturecof great? importance in the preserc. vation; of. the tensile strength of; suchi-ya-rn-v is the prompt andioomplete remoualzofthe acid as soon as regenerationbathe/cellulose attained: sub;-

stantial completion so as to avoid acidattack'on,

the cellulose andi'consequent degeneration thereof. In after-treating packages of such synthetic thread much; difficulty has: been'a experienced in securing adequate penctrationoftheatter-treating liquids into the layers of yarn so that it sometimes occurs that complete treatment of the packages' required such a long period of time that acid" degradation of" the yarn was; experienced, While such a condition-can in'some small meassure be tolerated-in yarn-of ordinary commercial quality having less than 100- filaments, the-com;- plete removal of impuritiesfrom each portionof each'filament' as'rapidly as possible becomes'of paramount importance where the utmost strength of; every'filament is depended upon, as in the production of, fabric "for heavy duty tires," etc;

In the ordinary production of synthetic, yarn by the stretch" spinning method the bundle of filaments forming the yarn assume a parallel arrangement and lie substantially in one plane thus forming a flat ribbon like yarn strand. Prior art teaches (see British Patent No. 297,063) that 2 liquid penetration of a yarn? package is better effected when the filaments composing the yarn are twisted; I have? discovered that it is not the twistingbut the" arrangement ofthe filaments in the form of a circular cylindrical bundle, rather than in a flat ribbon like strand, that effects-better penetration of after-treating liquid into-the yarn package; United States Patents Nos;

1,492,316 and"2,036,174" both disclosemea-n's for at least partially twisting a yarn' either during or preparatory to liquid treatment. So'far'as I am'- aware however there is" no prior art which combines shaping a' yarn strand with" the stretching of the filaments of which" the strand" is composed and immediately packagingthe'yarn' for after-- treatment.

The primary object of this'invention is to re duce to a minimum the-timerequired adequately to remove-the impurities from freshly'spunsyn thetic yarn having at least loofilamentsz Another object" is wanna-re the washing; out" of the acid as soonas'regeneration of thecellulose content-ofthe yarn' is completed.

A furtherobject isto so orient the filaments" of a yarnstrand immediately'be'fore its collectionthat' eaclrportiorrof the strand retainsasubstan'- tially circular" cylindrical cross section" sothat when the strandis cross-wound on'a perforated, bobbinin a plurality of layers it ftn'ms' apackage which is-readily pervious" to after-treating fluids.

The above-and other objects may be' attained? by employing this invention which embodies among its features; a guide roller having; a plurality of spaced: flanges, the said guide roller being at an angle to andop'eratin'g'in conjunc' tion with a godetwheel around both of. which the yarn on its way} from its source of origin to its point of collectionis given a'numberofhelical turns in such a manner'that' it rides th'eflanges and is thereby given a slight rolling movement Fig. 2 is a front view of a godet wheel and a guide roller assembly as employed in connection with this invention,

Fig. 3 is a side view of Fig. 2, and

Fig. 4 is a fragmentary sectional view through a thread package embodyin this invention.

Referring to the drawings in detail a spinning machine designated generally l includes a spinning trough l I containing a coagulant into which a. spinning solution is introduced through a spinning pump with candle filter I2 and goose neck l3 which terminates beneath the surface of the coagulant in a spinnerette (not shown). Mounted above the spinnerette on a substantially horizontal axis is a godet wheel and guide roller I4 and [5 respectively about which the thread l6, formed by contact of the spinning solution with the coagulant, is wound for a few turns in the form of a helix. Mounted adjacent and coextending parallel with the trough II is a trough I'l containing a hot aqueous liquid having a temperature above 60 0., preferably hot water,

beneath the surface of which is disposed a guide roller (not shown) about which the thread upon leaving the godet and guide roller l4 and I5 is guided.

From the guide roller, which is immersed in the hot, aqueous liquid, the thread passes upwardly to a second godet wheel l8 which operates about a horizontal axis at a somewhat higher peripheral speed than the godet wheel I4 so as to impart stretch to thread as it passes through said hot liquid. Mounted adjacent the godet wheel [8 on an axis of about 14 to the horizontal is a guide roller [9 having formed in its periphery a plurality of spaced grooves in which the thread is laid in the form of a helix. As shown in Fig. 3 the thread entering the grooves rides the flanges as it traverses the godet wheel [8 and guide roller 20, and the filaments forming the thread are thus condensed and manipulated so as to form a strand which is substantially circular in cross-section.

Leaving the godet wheel l8 and guide roller I9, the thread thus formed into a strand of circular cross-section passes downwardly beneath a grooved guide roller 2| and thence upwardly through a traverse mechanism 22 to a collecting bobbin 23 upon which the strand is cross-wound in a package 24 ready for further treatment.

Due to the circular cross-section of the thread strand the thread layers in the package 24 form interstices 25 (Fig, 4) through which treating fluids readily can pass, and hence the acid and impurities contained in the thread can be removed before any deleterious effects are experienced.

Actual tests have shown that thread packages produced under ordinary conditions in which the thread strand assumed a fiat ribbon like form, possessed a perviousness which would allow them to pass only about six and one-half liters of liquid per hour whereas like bobbins wound under like conditions except that the thread strand was so shaped as to be circular in cross-section possessed a perviousness which enabled them to pass over forty liters of liquid per hour. Tests made on bobbins wound with 1100 denier high strength yarn containing 480 filaments in accordance with this invention, show substantially complete acid removal with standard pressure vacuum washing equipment in a period of fifteen minutes whereas like tests made on bobbins wound with like yarn in accordance with the conventional practice and washed as recited above, show at the end of a sixty minute washing period an acid content of over fifty percent of that initially contained in the package. As a consequence, by employing this invention the high strength imparted to the yarn due to the stretching and hot water treatments can be preserved and the acid and impurities can be flushed out of the yarn package as soon as regeneration is completed.

While in the foregoing there has been shown and described the preferred embodiment of this invention, it is to be understood that minor changes in the details of construction, combination and arrangement of parts may be resorted to without departing from the spirit and scope of the invention as claimed. The term high-tenacity rayon yarn denotes yarn spun from viscose, cuprammonium cellulose, viscose-casein solutions, etc. having at least 2 grams dry strength per denier,

I claim:

In the method of producing high tenacity rayon yarn wherein a spinning solution is extruded into a spin bath under conditions to form a multifilament yarn strand, the resultant strand being then directed through a hot aqueous liquid, sub jected to stretch, and finally collected on a perforated bobbin in the form of a cross-wound takeup package ready for after-treatment, the improvement comprising the steps of forming said multifilament strand in a spin bath of relatively low temperature, withdrawing the strand as fast as formed from the bath by means of a first godet and roller unit before complete regeneration has set in, then passing said strand through an aqueous bath of substantially higher temperature to accelerate regeneration thereof, withdrawing it therefrom by means of a second godet and roller unit driven at a slightly higher peripheral speed than said first unit to impart stretch to said strand, and, while stretching said strand and while the regeneration thereof is continuing in accelerated fashion, abruptly changing the path of said strand a plurality of times for a short distance of travel and in such angular directions during its passage over said second godet as to impart a rolling motion thereto and cause it to acquire a lasting, substantially circular cylindrical shape and collectin said circular strand into a cross-wound package having a multitude of interstices.

CARL F. GRAM.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date Re. 22,178 Oppenlaender Sept. 15, 1942 1,820,621 Junkers Aug. 25, 1931 1,966,487 De Long July 17, 1934 1,968,912 Schrenk Aug. 7, 1934 2,074,022 Oppenlaender Mar. 16, 1937 2,110,926 Williams Mar, 15, 1938 2,303,274 Herrstrom et al. Nov. 24, 1942 2,317,747 Ewing Apr. 27, 1943 2,325,127 Gladding July 27, 1943 2,369,190 Thurmond Feb. 13, 1945 2,370,180 McCrosky Feb. 27, 1945 2,439.829 Tippetts Apr, 20, 1948

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