US3131429A

US3131429A - Funnel for stretch-spinning cuprammonium staple fiber

Info

Publication number: US3131429A
Application number: US87256A
Authority: US
Inventors: Okamura Osamu
Original assignee: Asahi Chemical Industry Co Ltd
Current assignee: Asahi Kasei Corp; Asahi Chemical Industry Co Ltd
Priority date: 1960-05-24
Filing date: 1961-02-06
Publication date: 1964-05-05
Anticipated expiration: 1981-05-05

Description

y 5, 1964 OSAMU OKAMURA 3,131,429

FUNNEL FOR STRETCH-SPINNING CUPRAMMONIUM STAPLE FIBER Filed Feb. 6 1961 INVENTOR. OSA MU OKAMURA United States Patent 3,131,429 FUNNEL FQR STRETCH-SPINNING CUPRAM- MQNIUM STAELE FIBER Osamu Olramura, Nobeolra-shi, Japan, assignor to Asahi Kasei Kogyo Kabushilri Kaisha, Osaka, Japan, a corporation of Japan Filed Feb. 6, 1961, Ser. No. 87,256 Claims priority, application Japan May '24, 1360 1 Claim. (Ci. 188) This invention is concerned with a method for economically manufacturing cuprammonium staple fiber which has excellent strength or both excellent strength and elongation by the so-called down-flowing stretch spinning method, and a spinning funnel employed therefor.

In the previously known down-flowing stretch spinning method employed for manufacturing cupramrnonium rayon, a spinning solution extruded through a spinneret into the funnel is first stretched by a down-flowing stream of a coagulating liquid and simultaneously coagulated partially to form filaments, and secondly is further stretched, being coagulated more and more, by tension of winding from outside in addition to the stream, with the result that the filaments have a higher speed than the flowing speed of the coagulating liquid and finally are stretched as much as several hundred times in the funnel. The manufacture of cuprammonium staple fiber is by the same principle, too. However, so far as an apparatus is concerned, it is not the same, because of the facts that, (1) in the production of staple fiber, it is absolutely necessary to separate the adjacent fibers from each other so that the staple fibers are not conglutinated to each other; (2) denier of each staple fiber ranges widely from 1 to 3.0 or more up to such as 5.0 and 7.0, while denier of rayon normally is 1.0-1.5; and (3) the total denier of the fibers produced from one funnel is requested to be large enough to such a degree as desired from economical view point. From the foregoing, it will be seen that long resident period of time in the funnel is required for the spinning solution to complete coagulation, that is to say, total length of the funnel must be long, and diameter of the spinneret should be made larger. In the conventional funnel, diameter of the spinneret was more than 8 cm., and whole length of the funnel more than 100 cm. When cuprammonium staple fiber is produced by the use of such type of spinning funnel, the spinning solution extruded through the spinneret is coagulated slowly in the long funnel and stretched slowly under tension according to such proceeding of slow coagulation.

According to the various recent studies on spinning of regenerated cellulose, however, it has been found that the physical properties of the regenerated fiber, such as tenacity and elongation depend considerably on how coagulation of filaments is effected at the time when they are stretched in the spinning process, and that fiber of excellent physical properties are obtained only when filament in adequately coagulated state is stretched. Notwithstanding such studies, cuprammoniurn staple fiber now on sale we not satisfactory in physical properties. It shows that the combination of coagulating and stretching is not successful. Recently, improvements in physical properties of the artificial cellulose fibers are desired, accompanying with appearance of various synthetic fibers. Particularly at present when the blended spinning of the former and the latter is strongly demanded, increases of tenacity and elongation, as well as breaking energy, and improvement in resin finishing property of the artificial fibers are highly desired.

Various attempts to improve the physical properties are reported. For example, there are so-called aftertensioning, i.e., various tensions are given to filaments just after leaving the spinning funnel, and a method wherein rapid stretching of filaments is effected by means of flow of a coagulating liquid while the filaments are not completely coagulated in the funnel to make them fine and then contacted to the coagulating liquid for comparatively long period of time. Although the improvement in tenacity could be attained by such ways, reduction of elongation of the product filaments cannot be avoided since the tension is given under a severe condition or for comparatively long period of time. The artificial cellulose fiber having only some strength but poor elongation has improved crystallization and crystalline rearrangement in the filament, but lacks elastic portion, with the result that the fiber is brittle and has small breaking work energy and poor resin finishing properties.

In the accompanying drawings, FIG. 1 is a vertical section view of an exemplified spinning funnel of the invention and FIG. 2 is a vertical section view of a spinning funnel employed heretofore. It is an object of the present invention to provide a method and a funnel for manufacturing cuprammonium staple fiber having high tenacity, elongation and uniform sectional structure.

The present invention will be fully explained hereinunder, comparing with the conventional method.

In the conventional method, the spinning funnel as et forth in FIG. 2 is employed for spinning. The transformation process of thread in this case will be minutely explained in connection with its faults. The spinning solution extruded through the spinneret into the funnel as mentioned above is at the first lightly stretched by means of coagulating liquid flowing in the funnel and at the same time, subjected to coagulating action by the coagulating liquid to form a partially coagulated state, but the stretching given at this stage is not so high that a higher degree of micell rearrangement is not formed within the partially coagulated filaments. This is the first fault. After this stage, the coagulation of the filaments is gradually advanced with ammonia diffusion from the filaments. Breaking of once formed skin structure of the filaments cannot be avoided since the strong stretching is continued even after passed a point where rapid turbulent diffusion occurs. This is the second fault. After all, the product filaments has uneven sectional structure, thereby to not provide the filaments with superior physical properties.

While, according to the present invention, the method is provided that the spinning solution is extruded through spinneret into the funnel to form partially coagulated filaments which are strongly stretched by means of a rapid fiow of the coagulating liquid to provide with a higher degree of micell rearrangement reasonably, and thereafter the filaments are relaxed by sudden decrease of flow speed of the coagulating liquid, and then they are completely coagulated. By the use of such method, the filaments become, in the first rapid stretching stage, fine enough that it needs hardly any further stretching, and in the second stage the relaxation of the tension by sudden decrease of flow speed of the coagulation liquid causes the micell rearrangement provided in the previous rapid stretching to be adequately moderated, and then coagulation is completed to fix the moderated micell rearrangement. Thus, excellent fiber having quite even sectional structure and increased tenacity as well as elongation is obtained.

Then, the apparatus for carrying out the method of the invention, i.e. spinning funnel, will be fully explained hereinunder.

The present invention is fully described referring to the accompanying drawing. In FIG. 1, 6 is spinneret mounting means, 4 is a spinneret, and l is a conical tube located under and distanced from the spinneret 4 to provide with suficient space to introduce a coagulating liquid. A spin ning solution is fed from an upper flowing pipe to means 6 and discharged through a number of fine holes into the coagulating liquid. The coagulating liquid is fed from the bottom of cylindrical tube '7 surrounding conical tube part of the conical tube by the action of the coagulating liquid since the conical tube is short in its length and is suddenly narrowed. If the coupling of the conical tube with the straight long tube is not made flat, the spinning 1, and flows into conical tube 1 accompanying with the 5 solution extruded through the orifice of the periphery part spinning solution. The spinning solution and the coaguof the spinneret runs down and adheres to the lower Wall lating liquid flow down through the conical tube and pass surface of the conical tube due to the greater effect of the through a straight long tube 2 of smaller diameter, wherespeed and the weight thereof than the effect of the flow in the spinning solution is not completely coagulated so of the coagulating liquid, thereby causing difiiculties in that it is drawn to the utmost possible extent by torrent 1 the spinning operation. However, if the inside diameter of the coagulating liquid. 3 is a coagulation tube or an d of the lower end of the conical tube is 1.2-2.0 times as expanded straight tube whose diameter is greater than. that much as the inner diameter d of the straight long tube of the tube 2, and the lower end of the tube 2 is inserted and the coupling part coupling these tubes is made flat, into the closed upper end of tube 3. The torrent of the adhesion of the spinning solution to the lower wall surface coagulating liquid in tube 2 enters suddenly the coagulaof the conical tube is prevented and furthermore the flow tion tube 3 so that flowing speed is suddenly and greatly of the coagulating liquid is not disturbed. The inner direduced. The filaments drawn to the utmost extent are ameter of the straight long tube d may be varied dependloosed or relaxed and are completely coagulated. ing upon the amount of the coagulating liquid and the The filaments in tube 3 are taken out by drawing applied spinning speed, but it is so decided that the flowing speed from the outside reeling or winding device without being of the coagulating liquid in the tube is 254 2 times of almost subjected to further stretching. the spinning speed. But it should not be less than 1.5 The spinning funnel apparatus for cuprammonium stacm. The length of the straight long tube 2 is adequately ple fiber employed heretofore is as shown in FIG. 2. The varied depending upon the elongation required for the spinning solution extruded through the spinneret is subproduct, and it is $5 times of the total length of the jected to moderate tension and elongation by the comparafunnel. The inner diameter d of the tube 3 is so detertively long conical tube and the coagulation tube so that mined that the flowing speed of the coagulating liquid is the stretching of the filaments under tension proceeds 2 2 times of the spinning speed. But, it should not even at the lower part of the coagulation tube where the be less than 2.0 cm., and the inner diameter d of the cocoagulation is considerably advanced. Consequently, the agulation tube should in all cases be larger than the inside filaments are subjected to unreasonable tension. Thus, diameter d of the straight long tube. The spinning speed use of the conventional apparatus necessarily gives inferior stated herein is defined by the speed of the filaments at the filaments in tenacity and elongation in comparison with outlet of the coagulation tube 3. that according to this invention since adequate crystal- Experimental values of some examples of the method lization and micell rearrangement in the inner structure and the spinning funnel apparatus of this invention will of the filaments are not obtained in the case of the conbe set forth, comparing with that of the conventional apventional apparatus. paratus. The spinning solution employed is a cuprarn- In the preferred embodiment of the apparatus, the monium cellulose solution (10% cellulose, 7.3% ammoupper inside diameter d of the conical tube 1 is not more nia, and 3.65 copper) produced by the method known than 2 times of the diameter of the spinneret 4 (more than heretofore.

Dimension of the funnel Physical properties of the filaments Method 13 L1 DS DE Ws WE (111111.) B; (mm) (mun) L2 (111111.) Den. (g./d.) (per- (g.ld.) (percent) cent) Conventional 125 35 320 1,280 1.5 2.43 14.2 1.62 19.0 method 125 35 320 1, 220 2.0 2. 14.1 1.58 19.5 155 35 550 1.930 3.0 2. 54 15.5 1.72 19.1

1 2 d1 11 l1 11 (111111.) (mm) (mun) (mm) (mm) (mm) Method of the 120 20 35 180 800 800 1.5 3.22 121.5 2.20 24.3 prescntin- 120 20 35 180 400 1, 000 1.5 3.05 18.0 2.13 21.9 vention (A) 120 20 35 180 800 1,500 2.0 3.01 17.0 2.13 20.0 120 25 35 180 800 1,500 2.0 3. 25 15.6 2.15 20.2 Method eithe i 155 30 800 1, 230 3.0 2. 08 17.3 2.31 21.3 present in- 20 35 180 400 1, 000 1.5 3.31 1 1.3 2. 41 13.9 vention (B) 120 20 35 400 1, 900 2.0 3.23 14.6 2.03 21.0 30 35 400 400 1,580 3.0 5. 22 15.4 2. 25 18.8

Method A: Increased both tenacity and elongation. Method B: Increased only tenacity.

8 cm.), and that the length 1 of the conical tube is within /5 of the total length of the funnel, though it may be adequately varied depending upon denier or the filaments to be spun, total denier (more than 1,000 denier) and total length of the funnel (more than 100 cm). The inside diameter d of the lower end of conical tube should be larger than the inner diameter d of the straight long tube 2, Le, 1.2-2.0 times as much as the d and the coupling part coupling the conical tube with the straight long tube should be made fiat and horizontal. This is because the spinning solution extruded through the spinneret is rapidly collected in the central What I claim is:

Apparatus for stretch spinning of cuprammonium staple fiber, comprising a spinneret, a sharply downwardly convergent conical tube having an upper inside diameter a and a lower inside diameter d and a vertical dimension L the ratio of diameters d zd ranging from (1245.5) :(l.86) and L ranging from 18-40, said conical tube further having a flat bottom and being positioned beneath said spinneret, a long straight tube connected to said fiat bottom and having an inside diameter ri and a coagulation tube connected to the bottom of said long tube, the inside diameter (i of the lower flat end of the conical tube being greater than the inside diameter d of the long tube in a ratio of 1.2-2, and the inside diameter of the coagulation tube being greater than the inside diameter of the long tube.

References Cited in the file of this patent UNITED STATES PATENTS 1,590,594 Taylor June 29, 1926 6 Elsaesser Oct. 25, 1927 Hartmann Oct. 20, 1931 Knehe July 14, 1942 Aizawa et a1 Aug. 21, 1962 OTHER REFERENCES