US2422021A - Manufacture of thread or the like - Google Patents

Description

Patented June 10, 1947 UNITED STATES PATENT OFFICE MANUFACTURE OF THREAD OR THE LIKE No Drawing. Application July 29, 1940, Serial No. 348,234

16 Claims.

This invention relates to the manufacture of tubes, ribbons, strands, threads, filaments, etc., hereinafter referred to as thread, by extruding a coagulable mass into a medium which serves to solidify it. More particularly, the invention is directed to the problem of rendering innocuous the relatively high content of otherwise objectionable substances introduced into the thread-forming system by or during coagulation operations. For convenience, the invention will be described in connection with the manufacture of multiple filament viscose artificial silk thread, although it may be employed to advantage, at least in certain of its aspects, in connection with the manufacture of other products formed by the extrusion of a coagulable mass into a coagulating medium.

Multiple filament artificial silk viscose thread is formed by extruding an aqueous solution of sodium cellulose xanthate ("viscosel, which forms one phase of the thread-forming system, through a multiple-orifice spinneret of noble metal or a noble metal alloy into an acid coagulating liquid, which constitutes another phase of the thread-forming system. The coagulating liquid usually includes sulfuric acid, sodium sulfate, a small amount of zinc sulfate, and, if desired, other substances beneficial in the production of the thread. After its extrusion from the spinneret, the viscose reacts with the coagulating liquid to form, on one hand, the reconstituted cellulose of which the thread is primarily composed and, on the other, such by-products as sodium sulfate, carbon disulfide, hydrogen sulfide, and free sulfur, some of which are highly undesirable.

Sundry impurities; viz., hemi-celluloses, complex sulfur compounds, insoluble compounds of calcium and silicon, and certain compounds, such as the thiocarbonates of metals such as lead, iron, etc. are also introduced into or form in the thread-forming system, either from impurities in the viscose or from the coagulating liquid. For example, the reagents employed to make up the viscose and coagulating liquid often contain impurities, while metallic conduits or containers through which the coagulating liquid and viscose pass introduce metallic impurities. Most, if not all, of such substances tend to deposit in or about the orifices of the spinnerts, particularly if they are of metal, and if the formation of such deposits is not controlled, their presence soon causes operating difficulties.

In general, it appears that such substances, unless prevented or controlled, tend to form two kinds of deposits upon the spinnerets: deposits on the perforated face of the spinneret in contact with the coagulating liquid, generally taking the form of a crater-like formation around each spinneret orifice, and deposits within the orifices,

usually taking the form of a ring-like deposit cated near the discharge end of each orifice. The

presence of certain metallic ions in the coagulating liquid promotes the formation of such deposits. For example, zinc ions from the zinc sulfate, which is added to the coagulating liquid because it has a supposedly beneficial effect on the thread characteristics, apparently promote the formation of harmful deposits.

The deposits outside of the orifice; i. e., the crater-like deposits, appear to be caused primarily by substances in the coagulating liquid, such as sulfur, insoluble metal compounds, etc. The deposits within the spinneret orifices appear to be caused primarily by substances originating in the viscose, such as cellulose, hemi-celluloses, silicates, etc., as well as substances present in the coagulating liquid. It is believed that the coagulating liquid penetrates into the discharge ends of the spinneret orifices and, by coagulating the viscose, precipitating substances in the viscose, or by precipitating substances from the coagulating liquid, aids in forming such deposits in the spinneret orifices.

Deposits thus formed in and about the spinneret orifices grow in size and tend to reduce the denier of individual filaments and even to block the orifices completely, producing broken filaments and/or snarls of the type known to the trade as fish-hooks" or spinning-hooks." Such deposits are, in general, very hard and can be eliminated from the spinneret only with difliculty, it being necessary to remove the spinneret from the spinning machine in order to clean it: for example, prolonged treatment with hot concentrated sulfuric acid and then with heated caustic solution or even treatment with fuming sulfuric acid may be required to remove the deposits. Considerable time and expense is involved in cleaning the spinnerets and in removing them from and replacing them on the spinning machine.

Formation of the above-mentioned deposits of substances in the thread-forming system is apparently due to the high degree of afiinity which particles of such substances have for each other, for other suspended particles in the thread-forming system, or for the metal of which the spinnerets are formed. The affinity exhibited by sulfur and similar particles for each other is believed to be so great in most cases that, unless inhibited, large craters" are built up around the orifices of the spinneret in a short period of time.

Similarly, the particles of material of which the so-called rings within the spinneret orifices are composed are believed to have such an affinity for each other and for the spinnerets that such rings form in a relatively short time.

The size, location and nature of the deposits in and about the spinneret orifices appear to depend,

at least in part, upon the degree of acidity and alkalinity existing in the region of such deposits.

For example, certain contaminants going to make up craters and rings may be soluble or remain suspended in the alkaline viscose solution, but may be rendered insoluble or precipitated when exposed to the acid coagulating liquid, wherefore they may pass through their respective iso-electric points as the viscose passes through the spinneret orifices from the interior of the spinneret to the coagulating liquid. It is believed that such substances passing through their isoelectric points may be precipitated from the viscose and deposited upon substances in the precipitating region for which they have a preferential affinity; e. g., similar discrete particles or even the metal of which the spinnerets are composed. That the formation of the deposits within the spinneret orifices may be largely due to such an effect is indicated because the region near the discharge end of each spinneret orifice in which such deposits form appears to be the region in which the viscose is first subjected to the acid coagulating liquid.

The particular metal or alloy employed in the spinneret has been found to determine to a certain extent the facility with and rate at which such deposits are formed: it appears, for example, that deposits form more readily on gold-palladium spinnerets than on platinum-rhodium spinnerets.

When no steps are taken to inhibit the formation of deposits on the spinnerets, it is not unusual under ordinary spinning conditions to have to replace a large proportion of the spinnerets during each twenty-four hours of operation. Inasmuch as a plant of even moderate size will have as many as 10,000 or more spinnerets in operation at one time, a very substantial amount of time and labor will necessarily be lost in making such replacements. The economic loss is great even in discontinuous processes of manufacturing viscose artificial silk thread; i. e., in potand spool-spinning processes, in which each thread passes directly from a spinneret to a collecting deViCe of limited capacity. However, the dimculties arising out of such conditions and the economic waste accruing therefrom are of even greater consequence when viscose artificial silk thread is produced by so-called continuous processes.

In general, in the continuous process thread proceeding from a spinneret to a collecting device is subjected, during its passage, to a variety of processing treatments on a series of thread-advancing devices each of which continuously but temporarily stores the thread in a large number of generally helical turns. In such a process, when a thread breaks because of a clogged or fouled spinneret or is intentionally broken for necessary cleaning or replacement of the spinneret, all of the thread store devicesto which the thread would subsequently pass, which may be as many as ten or more, must be threaded up again. This, of course. requires time and labor and involves a considerable loss of production time.

Regardless of the method of production, thread leaving the coagulating bath tends to carry with it extraneous substances present in the threadforming system. If such substances are of sufficient concentration or have a strong affinity for the thread, they may interfere with the aftertreatment of the thread, as, for example, by causing objectionable side reactions. Under other conditions, they may be carried out of the bath and deposited on parts of the apparatus with which the thread comes into contact, forming incrustations which damage the thread. In continuous processing apparatus, for example, interference with the after-treatment of the thread and the formation of such deposits are most likely to occur on the aforementioned thread-advancing devices since the thread passes to such devices within a very short time after its formation and preferably is stored thereon for a period of time sufficient to favor the formation of such deposits or incrustations.

It is apparent, therefore, that the presence of impurities and by-products of the coagulation reaction in the thread-forming system is responsible for many operating difficulties. Since most, if not all, of such impurities arise from the coagulation reaction or are introduced by the viscose, their amounts tend to increase. Were the substances in question characterized by particles of substantial size, they could presumably be removed by filtering. Such substances are, however, more or less colloidal in character and hence removable only with difficulty.

It has been suggested heretofore that cationactive substances should be employed in the thread-forming system to inhibit the harmful effect of particles of impurities.

According to the present invention, it is possible to employ in the thread-forming system anion-active substances and certain polyoxyhydrocarbon substances which are neither cationnor anion-active. According to the invention, at least two substances are incorporated in the viscose or in the coagulating liquid: viz., (a) a substance which has the property of selectively wetting deleterious particles in the thread-forming system in such manner as to reduce their affinity for each other and for the spinnerets and/or the property of selectively wetting the spinneret surfaces and (b) a substance which acts as a dispersing agent. Both the selective wetting agent and the dispersing agent are of types which are readily available commercially.

Such agents, used together, inhibit and often entirely prevent the formation upon parts of the apparatus over which the thread passes of harmful deposits of impurities carried by the thread from the coagulating liquid.

Under some circumstances, moreover, the added materials may cause the colloidal substances present in the thread-forming system to form a floc, either floating, suspended or precipitated. which may be removed from the coagulating liquid continuously or from time to time, as by filtration, flotation, or settling. Among other impurities, considerable amounts of sulfur may thus be separated from the system. In this manner, the same coagulating liquid may be re-used indefinitely without fouling spinnerets, guides. thread-advancing thread store devices, etc., provided the desired concentration of wetting and dispersing substances is maintained in the thread-forming system.

The characteristics of the wetting agent and the dispersing agent when incorporated in the acid coagulating liquid are apparently of considerable importance in the practice of the present invention. Even if either or both of these agents is employed in the viscose rather than in the coagulating liquid, most, if not all, of the agent passes into the coagulating liquid. The action of such agent or agents in inhibiting harmful depositions upon the spinnerets and parts of the apparatus is thus eifected upon other of the agent or physical or physico-chemical properties such that,

when in the acid coagulating liquid, it exerts a selective wetting action on and forms a film over the insoluble particles which tend to form spinneret deposits and/ or the surfaces of the spinneret on which deposits tend to form. Preferably, the selective wetting agent is such that when carried by the coagulating liquid into the discharge'ends of the spinneret orifices, it is de posited in said orifices in the form of a film.

This wetting action on the inner surfaces of the spinneret orifices and the wetting action on the impurities which go to make up the spinneret deposits inhibits, if not prevents, the formation of deposits within the spinneret orifices; indeed, the wetting agent primarily inhibits deposits inside the spinneret orifices.

While the wetting agent substantially inhibits, if not entirely prevents, the formation of rings within the spinneret orifice by reducing or perhaps entirely destroying the afiinitive bonds between the particles of contaminants which would form such deposits and/or between such particles and the spinnerets, the wetting agent when used alone does not usually inhibit the formation of deposits, such as craters, on the face of the spinneret outside of the orifice. Under some circumstances, such added selective wetting agent is found in the deposit formed on the surface of the spinneret, usually in the form of a coating around the particles of the substances which ordinarily form the spinneret deposits.

Therefore, according to the present invention, there is also employed in the thread-forming system in conjunction with the selective wetting agent another agent which has a dispersing action on the sulfur and other insoluble particles in the coagulating liquid, including the selectively wetted contaminants. The dispersing action of such agent is such that it inhibits, if not entirely prevents, the formation of deposits on the spinneret, particularly on its face. Since particles of impurities going to make up the deposit are wet by the wetting agent and consequently do not tend to cling to each other and to the spinneret with so great an aflinity as would be the case if the selective wetting agent were not employed, they are readily dispersed by the action of the dispersing agent and caused to remain suspended in the coagulating liquid, at least in the vicinity of the spinnerets.

Any one of numerous dispersing agents may be employed for the purposes of the present invention. It is desirable that the dispersing agent, whether added to the viscose or to the coagulating liquid, shall be soluble in the coagulating liquid, preferably molecularly soluble but at least partially molecularly and partially colloidally soluable; however, it may form a colloidal solution. When incorporated in the coagulating liquid, it should have a dispersing action on the impurities in the coagulating liquid and should be neutral or negatively charged in the sense that it should be anion-active if it ionizes to any considerable extent or, alternatively, should form negatively charged colloidal particles. It may, of course, give rise to negatively charged particles and at the same time be somewhat anionactive; as a matter of fact, this is the usual case.

Generally speaking, the more active the dispersing agent, the lower is the concentration necessary to provide the desired result; however, to a certain extent its action is influenced by the wetting agent, with which it is used. In general, a powerful dispersing agent, employed in conjunction with a suitable wetting agent, will operate to keep the face of the spinneret adjacent the discharge ends of the spinneret orifices entirely clear of deposits, while at the same time the wetting agent will operate to inhibit, if not entirely prevent, the formation of rings within the orifices. Under suitable conditions, as where the selective wetting agent forms a film on the wall of each of the spinneret orifices, no deposits inside the orifices are found.

If the dispersing agent is not sufiiciently powerful, the formation of deposits on the face of the spinneret may not be entirely prevented and crater-like formations may occur. Such deposits are, however, so friable as to offer no interference with the spinning operation. As the deposits tend to build up, they are worn down by the filaments issuing from the spinneret orifices so that they cannot grow beyond a certain size. The deposits are so soft that even though they come into contact with freshly formed thread, no damage is done to the thread; indeed, they are usually so soft that they may be removed from the spinneret by swinging the spinneret out of the coagulating liquid, allowing viscose to flush through the spinneret orifices; by a wiping operation; or by washing with water.

While deposits forming in or about the spinneret orifices may not be suppressed indefinitely, the time during which the spinnerets ma operate without breakage of the thread issuing therefrom is very greatly increased over that possible in ordinary practice. The percentages of spinnerets which must be changed is reduced to as low as 1%; indeed, in the practice of the present invention, it is a common matter for spinnerets to operate for six days or more without interruptions. Under such conditions, the deposits which form upon the spinnerets include, besides the usual substances, substantial amounts of the agents added to the thread-forming system: it is believed that this accounts for the softness of such deposits.

While the precise action is not understood, it is believed that the fact that neutral or negatively charged wetting and dispersing agents are employed according to the invention plays a part in the success of the invention. Since the agents employed are either negatively charged or neutral, they are electrically compatible with the negatively charged particles of impurities. The wetting and dispersing agents employed according to the present invention may be defined as apositive" in the sense that they form negatively charged colloidal particles, are anion-active in solution, or are neutral in solution.

In the manufacture of viscose thread, the characteristics and composition of the viscose and the coagulating liquid may cooperate with the agents added to the coagulating liquid to inhibit harmin] spinneret deposits. Of particular advantage in this respect is viscose comprisin by weight: cellulose, 7.5% to 8.0%; sodium hydroxide, 6.2% to 6.8%; and total sulfur, 2.0% to 2.5%. Preferably, the viscose has a ripeness of 3.8 to 43' as measured by the sodium chloride salt index and a viscosity of approximately 41.5 to 60.5 poises. A coagulating liquid found advantageous for the practice of the present invention comprises by weight: sulfuric acid, 10.1% to 11.8%; sodium sulfate, 18% to 22%; zinc sulfate, 0.7% to 1.1%, practically all of the remainder being water except for addition agents of the nature contemplated by the present invention and impurities of the type above indicated. Preferably, the coagulating liquid in the vicinity of the spinnerets is maintained at a temperature of 45" C.

Selective wetting agents which may be employed include water-soluble alcohol esters of fatty acids having more than 8 carbon atoms in the molecule; esters of polyoxyhydrocarbon compound, such as tetraethylene glycol mono-oleate, which is sold under the trade-name Emulior AD by the General Dyestuffs Corporation: and water-soluble polymerized, long chain oxyhydrocarbon compounds of high molecular weight, such as those disclosed in copendin application Serial No. 348,235, filed July 29. 1940, by W. 0. Israel. Examples of the latter substances are the products sold by the Carbide and Carbon Chemicals Corporation under the trade-mark Carbowax," which are polyoxyethylene glycols of a high molecular weight. Compounds of the latter type of molecular weights not substantially below 2000 operate very satisfactorily.

The dispersing agent may be chosen from a large number of compounds of which the following are examples: Daxad 11" (approximately 85% sodium salt of a sulfonated naphthaleneformaldehyde condensation product and 15% Na2SO4); Daxad 23 (approximately 96% sodium salt of a sulfonated lignin, 3 to 4% NazSO; and 0.5% CaSO4); and "Daxad 'I'DA (a sodium salt of lignin sulfonic acid combined with triethanol amine), all of which are sold by the Dewey 8r Almy Chemical 00.; "Arctic Syntex T, which is approximately 40% CH; cnucnmcnzoruonmcoi icmcmsolxa the remainder being sodium sulfate, sold by Colgate-Palmolive-Peet Corporation; Aerosol OT," the sodium salt of dilauryl sulfosuccinate, sold by American Cyanamid 8; Chemical Corp; Sohio X Oil, the sodium salt of a sulfonated hydrocarbon sold by Standard Oil Co. of Ohio; Santomerse D, and alkali salt of an alkyl substituted aromatic hydrocarbon sulfonic acid sold by Monsanto Chemical Works; Ultrawet, the sodium salt of a sulfonated kerosene sold by Atlantic Refining Co.; Nacconol NR and Naconnol NRSF, which are alkyl aryl sodium sulfonates, and Nacconol Y a compound having the formula all of which are sold by the National Aniline and Chemical Company,

Examples of the invention are given hereinafter for purposes of illustration, but without limitation on the scope of the invention.

Example I Viscose of the kind heretofore described is extruded into a coagulating liquid having the composition given above, the coagulating liquid being maintained at a temperature of approximately 45 C. Extrusion is through platinum-rhodium spinnerets platinum, 10% rhodium) having 40 orifices of 0.0031 inch diameter. The rate of extrusion and draw-oil of the thread are so regulated as to produce thread of denier, 40 filament at a rate of approximately 68 meters per minute.

Such coagulating liquid has incorporated therein, by weight. 0.108% of Carbowax 4000," a polyoxyethylene glycol of a molecular weight of approximately 4000, and 018% of Daxad 11." The ratio of Carbowax 4000," which constitutes the selective wetting agent, to "Daxad 11," which constitutes the dispersing agent, is in this case approximately 6:1. While the Wetting agent is apparently wholly molecularly soluble in water, it appears to be only partially molecularly soluble, but without ionization, in the coagulating liquid, in which it forms a fine, cloud-like colloidal suspension. The dispersing agent apparently is neither cationnor anion-active in the coagulating liquid; instead, it appears to form a colloidal solution of negatively charged particles.

Harmful contamination of the spinnerets is inhibited under the conditions outlined, pursuant to which it is possible to spin for more than six days without changing spinnerets. The formation of harmful deposits on other parts of the apparatus contacted by the thread is prevented. Moreover, colloidal impurities in the coagulating liquid are so agglomerated that the coagulating liquid may be readily purified by filtering through cotton-excelsior filters of the conventional type.

Example I I In this example, the conditions indicated in Example I are maintained except that approximately 108% of Carbowax 4000" and .036% of Daxad 11 are incorporated in the coagulating liquid. The ratio of these two substances in this example is 3: 1. Results of the order of those indicated in Example I are provided by this combination.

Example III The conditions of Example I are the same with the exception of the amounts of the addition agents. In this example, about 072% or Carbowax 4000 and 054% of Daxad 11 are employed in the coagulating liquid. The ratio of the Carbowax 4000 to the Daxad 11 is thus approximately 4:3. Excellent results in the inhibition of harmful deposits upon the spinnerets and other parts of the apparatus are provided.

Example IV The conditions of Example I are as before, the amounts of the coagulating liquid addition agents, however, being different. In this example, approximately .0485% of "Carbowax 4000" and 036% of "Daxad 1 are employed in the coagulating liquid. In this case, as in Example III, the ratio is 4:3, but the amounts of coagulating liquid addition agents employed are considerably less than those in Example III. However, good result in the inhibition of harmful deposits are obtained.

Example V In this case, the amounts of Carbowax 4000 and Daxad 11 employed are identical, .072% of each being incorporated in the coagulating liquid. All other conditions are identical with those described in Example 1. Good results are provided along the lines indicated in Example 1.

Example VI Excellent results in the inhibition of harmful deposits and in the removal of impurities from the coagulating liquid are provided if more of the dispersing agent is employed than the substance serving as the wetting agent. Although all other conditions of Example I are maintained, only about 036% of the Carbowax 4000 and 072% of the Daxad 11, corresponding to a ratio of 1:2, are employed in the coagulating liquid, exceptionally good results being obtained.

Example VII In this example, the same ratio of agents is employed as in Example VI, the amounts, however, being considerably less. All other conditions are the same as described in Example I. That is. about 018% of "Carbowax 4000 and 036% of "Daxad 11 are employed, with results comparable to those of Example VI.

Example VIII In this example, all of the conditions outlined in Example I are maintained with the exception of the agents added to the coagulating liquid. In this case, there are incorporated in the coagulating liquid approximately 06% of Carbowax 4000" and the same amount of "Daxad 23. The latter comprises substantially entirely the sodium salt of a sulfonated lignin and is definitely anionactive in the coagulating liquid. Results in the reduction of harmful spinneret contamination and in the inhibition of harmful deposits on other parts of the apparatus comparable to those of the above examples are obtained.

Example IX In this example, all conditions other than the kinds and amounts of agents added to the coagulating liquid are identical With those of Example I. In this case, however, the coagulating liquid contains as the selective wetting agent about 036% of "Emulfor AD, which is a tetraethylene glycol mono-oleate, and, as the dispersing agent, about .0018% of "Daxad TDA," which is a combination of the sodium salt of lignin sulfonic acid and triethanol amine. The ratio of the wetting agent to the dispersing agent is approximately 20:1. The Emulfor AD does not ionize in the coagulating liquid but forms a colloidal solution of negatively charged particles. Daxad TDA" is definitely anion-active. The amount and rate of formation of harmful deposits upon the spinnerets and upon other parts of the apparatus is greatly reduced.

Example X In this case. the coagulating liquid contains about 072% of a polyoxyethylene glycol ("Carbowax) of a molecular weight of approximately 2000 and about 054% of Daxad 11," all other conditions being the same as those described in Example I. The ratio of the former to the latter is 4:3. The Carbowax appears to be only partially soluble in the coagulating liquid. The rare and amount of harmful contamination of the spinnerets is greatly reduced, as is the formation of harmful deposits on other parts of the apparatus.

Example XI In this case. but for the amounts and kinds of agents added to the coagulating liquid. conditions 10 are identical with those of Example I. The coagulating liquid contains approximately 072% of a "Clarbowax having a molecular weight of approximately 2000 and about 054% of Arctic Syntex," a dispersing agent which includes an active substance having the formula The ratio of the selective wetting agent to the dispersing agent in this case is thus 4:3. Arctic Syntex is anion-active in the coagulating liquid. Good results along the lines indicated in Example I are provided.

Example XII With the exception of the amounts and kinds of agents added to the coagulating liquid, the operating conditions for this example are also the same as those of Example I. In this example, however, the coagulating liquid contains approximately 072% of "Carbowax 4000 and .l08% of Arctic Syntex," which thus provides a ratio of 2:3. Very good results are obtained in the inhibition of splnneret deposits and deposits upon other parts of the apparatus, as well as in the ready separation of the impurities from the coagulating liquid.

Example XIII Viscose of the kind employed in Example I is spun into a coagulating liquid of the kind referred to in said example but containing no addition agents. The viscose contains by weight about 05% of Lubricant 4000" and 03% of Daxad 1 By the use of these agents in the viscose, the amount of harmful contamination of the spinnerets as reflected by the number of spinnerets which must be changed every 24 hours is greatly reduced. The agents thus incorporated in the viscose are carried into the coagulating liquid, as evidenced by the reduction in the amount of harmful contamination of the spinnerets and by the fact that the formation of harmful incrustations on other parts of the apparatus is inhibited.

Example XIV Viscose of the character employed in Example I; i. e., comprising by weight 7.5% to 8.0% of cellulose, 6.2% to 6.8% of sodium hydroxide, and a total sulfur content of 2.0% to 2.5% and having a ripeness of 3.8 to 4.3 as measured by the sodium chloride salt index is spun through platinum-rhodium spinnerets into a coagulating liquid comprising, by weight, from 7% to 9% of sulfuric acid, 18% to 20% of sodium sulfate, and from 2? to 3.75% of zinc sulfate, the coagulating liquid in the vicinity of the spinnerets being maintained at approximately 45 C. Threads of 2'75 denier, filaments. are spun at the rate of 40 meters per minute. The coagulating liquid contains approximately 018% of "Carbowax 4000" and .072"? of Arctic Syntex, the ratio in this case being 1:4. Despite the high percentage of Zinc, which tends to promote the formation of harmful spinneret deposits. excellent continuity of spinning is obtained; indeed, under such conditions. the thread may be spun continuously for a week or more. Harmful incrustation of spin bath contaminants upon parts of the apparatus with which the thread comes into contact are inhibited and the separation of such contaminants from the coagulating liquid is facilitated.

Extremely good results are obtained in the above examples with respect to inhibition oi harmful spinneret deposits and with respect to the reduction of spinneret changes even though the thread is spun vertically upward from the spinneret and even though it is withdrawn from the spinneret by a rotating take-up device to which the thread passes in a fixed path. It is recognized in the art that such conditions of spinning tend to facilitate the formation of harmful spinneret deposits. Angular spinning of the thread, particularly if accompanied by movement imposed upon the thread by a reciprocating guide, is known to retard the formation of spinneret deposits.

Although, as indicated, the type of metal of which the spinneret is composed influences the readiness with which harmful deposits form on the spinneret, spinnerets of metals other than that employed in the foregoing examples may be used with very good results. Gold-palladium spinnerets may, for example, advantageously be employed in each of the above examples in lieu of the platinum-rhodium spinnerets to which reference has been made, However, the presence of nickel in the thread-forming system, particularly it agents of the "Carbowax type are employed, may be detrimental: care should therefore be taken to guard against the presence of this element in the system.

It is desirable that a solution of either or both of the addition agents be prepared and that such solution be mixed with the coagulating liquid or with the viscose, as desired, either continuously or from time to time, in order to provide the desired concentration of agents. Where both agents are to be added to the coagulating liquid or to the viscose, they can in most cases be mixed in the desired proportions in the same liquid vehicle, preferably in about concentration; but in some cases, as where one of the agents has a high proportion of inactive ingredients, it may be desirable to mix the two agents in separate aqueous solutions which are added separately to the coagulating liquid or the viscose. In general, such solutions may be prepared by a simple operation, although a milling operation may be employed, if desired.

As previously pointed out, both of the addition agents may be added to the coagulating liquid or both be added to the viscose; but, if desired, one may be added to the coagulating liquid and the other to the viscose. In the latter case, it 1 desirable to incorporate the wetting agent, ich primarily inhibits the formation of deposits in the spinneret orifices, in the viscose and to incorporate the dispersing agent, which primarily inhibits the deposits on spinnerets outside of the orifices, in the coagulating liquid. As stated, it appears that in any case at least a portion of any agent added to the viscose passes into the coagulating liquid.

From the above examples, it is clear that no rule can be laid down as to the amounts or proportions of agents which are to be added. It appears, however, that only an extremely small amount of each agent is required as compared to the amount of coagulating liquid or viscose employed. Usually the selection of either the wetting agent or the dispersing agent is in part determined by the effectiveness of the other; indeed, there may in some instances be a certain amount of overlapping in respect of the properties of the wetting agent and the dispersing agent, since some compounds have both properties. Among selective wetting agents, however, wetting properties predominate, while dispersing agents have primarily dispersing properties. In cases 12 where the agents have overlapping properties, the desired propertiy in one agent is often reinforced by a similar property in the other agent.

By the proper selection of dispersing and wetting agents in suitable proportions, it is possible to spin thread under conditions in which no deposits form in or about the spinneret orifice, under conditions in which deposits form about the spinneret orifice but not in them, or under conditions in which slight deposits form within the spinneret orifice but no deposits form about the orifice, In all such cases, however, it is possible to spin for long periods of time, even with deposits on the spinnerets, with no degradation of the quality of the thread and without interruption in the continuity of the filaments. This follows from the fact that the deposits are extremely soft and, even if they come into contact with the freshly formed thread, do no harm.

Other selective wetting agents, other dispersing agents and other combinations of agents than those indicated above may be employed without departing from the spirit of the invention; indeed, in some cases, it is possible to employ three or more agents having the desired properties.

Moreover, the invention is not limited to the proportions of materials nor to the composition of the coagulating baths or of the viscose described in the above examples, for such proportions and compositions may be varied to suit particular cases. For example, difierences in the characteristics of the viscose and/or the coagulating liquid may require differences in the kinds and amounts of addition agents. It is apparent, furthermore, that the invention is not limited to the manufacture of viscose thread, but is applicable to the manufacture of extrusion products other than thread and to the manufacture of products of other processes than the viscose process, by discontinuous as well as by continuous processes. The term thread", wherever employed in the claims, is intended to include besides threads, such products as filaments, bands, tubes, strips, sheets, and other extrusion products; similarly, the term "spinneret" is intended to include other types of spinning nozzles.

It is intended that the patent shall cover, by suitable expression in the appended claims, whatever features of patentable novelty reside in the invention.

What is claimed is:

1. In the method of forming viscose thread, the step which comprises extruding viscose through a. spinneret i ito a coagulating liquid in the presence of a suriace active long chain polyoxyhydrocarbon polymer having a molecular weight not substantially below 2000 and an anion-active substance.

2. In the method of forming viscose thread, the step which comprises extruding viscose through a spinneret into a coagulating liquid in the presence of a water-soluble, surface active polyoxyalkylene glycol polymer having a molecular weight not substantially below 2000 and an anion-active substance.

3. In the method of forming viscose thread, the step which comprises extruding viscose containing a water-soluble, surface activ polyoxyalkylene polymer having a molecular weight not substantially below 2000 and an anion-active substance into a coagulating liquid.

4. In the method of formin viscose thread, the step which comprises extruding viscose through a spinneret into a coagulating liquid containing a water-soluble, surface active polyoxyalkylene 13 glycol polymer having a molecular weight not substantially below 2000 and an anion-active substance.

5. In the method of forming viscose thread, the step which comprises extruding viscose through a spinneret into a coagulating liquid in the presence of a water-soluble, surface active polyoxyethylene glycol polymer having a. molecular weight not substantially below 2000 and an anionactive substance.

6. In the method of forming viscose thread. the step which comprises extruding viscose containing a water-soluble, surface active polyoxyethylene glycol polymer having a molecular weight not substantially below 2000 and an anion-active substance into a coagulating liquid.

'7. In the method of forming viscose thread, the step which comprises extruding viscose through a spinneret into a coagulating liquid containing a water-soluble, surface active polyoxyethylene glycol polymer having a molecular weight not substantially below 2000 and an anion active substance.

8. In the method of forming viscose thread. the step which comprises extruding viscose through a spinneret into a coagulatin liquid in the presence of a water-soluble, surface active polyoxyethylene glycol polymer having a molecular weight of substantially 4000 and an anion-active substance.

9. In the method of forming viscose thread, the step which comprises extruding viscose containing a water-soluble, surface active polyoxyethylene glycol polymer having a molecular weight of substantially 4000 and an anion-active substance into a coagulating liquid.

10. In the method of forming viscose thread, the step which comprises extruding viscose through a spinneret into a coagulating liquid containing a water-soluble, surface active polyoxyethylene glycol polymer having a molecular weight of substantially 4000 and an anion-active substance.

11. The method as in claim 5 in which the anion-active substance is a salt of a sulfonated napthalene-formaldehyde condensation product.

12. The method as in claim 5 in which the anion-active substance is a salt of a sulfonated amide of a higher fatty acid.

'13. The method as in claim '7 in which the anion-active substance is a salt of a sulfonated naphthalene-formaldehyde condensation product.

14. The method as in claim 7 in which the anion-active substance is a salt of a sulfonatecl amide of a higher fatty acid.

15. The method as in claim 10 in which the anion-active substance is a salt of a sulfonated naphthalene-formaldehyde condensation product.

16. The method as in claim 10 in which the anion-active substance is a salt of a sulfonated amide of a higher fatty acid.

HAYDEN B. KLINE. ALDEN H. BURKHOLDER. WILLIAM 0. ISRAEL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,959,930 Schmidt et a1 May 22, 1934 2,037,974 Guenther et a1. Apr, 21, 1936 2,066,125 Rozenbrock Dec. 29, 1936 2,125,031 Polak et a1 July 26, 1938 2,166,314 Martin July 18, 1939 2,129,709 Schuette et a1. Sept. 13. 1938 FOREIGN PATENTS Number Country Date 328,675 Great Britain Apr. 30, 1930 449,792 Great Britain July 3, 1936 OTHER REFERENCES H. Bennett, Standard Chemical & Technical Dictionary, Chemical Pub. Co., Inc., N. Y., 1939.

Certificate of Correction Patent No. 2,422,021.

June 10, 1947.

HAYDEN B. KLINE ET AL.

It is hereby certified that errors appear in the printed specification of the above numbered patent requiring correction as follows: Column 7, lines 20 and 21, for the word compound read compounds; lines 63 to 65 inclusive, for that portion of the read column 12, line 2, for propertiy read property; and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 23rd day of September, A. D. 1947.

THOMAS F. MURPHY,

Assistant Oommiuianer of Patents;

13 glycol polymer having a molecular weight not substantially below 2000 and an anion-active substance.

5. In the method of forming viscose thread, the step which comprises extruding viscose through a spinneret into a coagulating liquid in the presence of a water-soluble, surface active polyoxyethylene glycol polymer having a. molecular weight not substantially below 2000 and an anionactive substance.

6. In the method of forming viscose thread. the step which comprises extruding viscose containing a water-soluble, surface active polyoxyethylene glycol polymer having a molecular weight not substantially below 2000 and an anion-active substance into a coagulating liquid.

'7. In the method of forming viscose thread, the step which comprises extruding viscose through a spinneret into a coagulating liquid containing a water-soluble, surface active polyoxyethylene glycol polymer having a molecular weight not substantially below 2000 and an anion active substance.

8. In the method of forming viscose thread. the step which comprises extruding viscose through a spinneret into a coagulatin liquid in the presence of a water-soluble, surface active polyoxyethylene glycol polymer having a molecular weight of substantially 4000 and an anion-active substance.

9. In the method of forming viscose thread, the step which comprises extruding viscose containing a water-soluble, surface active polyoxyethylene glycol polymer having a molecular weight of substantially 4000 and an anion-active substance into a coagulating liquid.

10. In the method of forming viscose thread, the step which comprises extruding viscose through a spinneret into a coagulating liquid containing a water-soluble, surface active polyoxyethylene glycol polymer having a molecular weight of substantially 4000 and an anion-active substance.

11. The method as in claim 5 in which the anion-active substance is a salt of a sulfonated napthalene-formaldehyde condensation product.

12. The method as in claim 5 in which the anion-active substance is a salt of a sulfonated amide of a higher fatty acid.

'13. The method as in claim '7 in which the anion-active substance is a salt of a sulfonated naphthalene-formaldehyde condensation product.

14. The method as in claim 7 in which the anion-active substance is a salt of a sulfonatecl amide of a higher fatty acid.

15. The method as in claim 10 in which the anion-active substance is a salt of a sulfonated naphthalene-formaldehyde condensation product.

16. The method as in claim 10 in which the anion-active substance is a salt of a sulfonated amide of a higher fatty acid.

HAYDEN B. KLINE. ALDEN H. BURKHOLDER. WILLIAM 0. ISRAEL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,959,930 Schmidt et a1 May 22, 1934 2,037,974 Guenther et a1. Apr, 21, 1936 2,066,125 Rozenbrock Dec. 29, 1936 2,125,031 Polak et a1 July 26, 1938 2,166,314 Martin July 18, 1939 2,129,709 Schuette et a1. Sept. 13. 1938 FOREIGN PATENTS Number Country Date 328,675 Great Britain Apr. 30, 1930 449,792 Great Britain July 3, 1936 OTHER REFERENCES H. Bennett, Standard Chemical & Technical Dictionary, Chemical Pub. Co., Inc., N. Y., 1939.

Certificate of Correction Patent No. 2,422,021.

June 10, 1947.

HAYDEN B. KLINE ET AL.

It is hereby certified that errors appear in the printed specification of the above numbered patent requiring correction as follows: Column 7, lines 20 and 21, for the word compound read compounds; lines 63 to 65 inclusive, for that portion of the read column 12, line 2, for propertiy read property; and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 23rd day of September, A. D. 1947.

THOMAS F. MURPHY,

Assistant Oommiuianer of Patents;