US3860685A

US3860685A - Method and apparatus for spinning multicomponent fibers

Info

Publication number: US3860685A
Application number: US767900A
Authority: US
Inventors: Kazumi Nakagawa; Keijiro Kuratani; Shinsaku Minami; Zoda Keiichi
Original assignee: Japan Exlan Co Ltd
Current assignee: Japan Exlan Co Ltd
Priority date: 1964-06-15
Filing date: 1968-09-17
Publication date: 1975-01-14
Anticipated expiration: 1992-01-14
Also published as: FR1440288A; GB1107117A

Abstract

A method and apparatus for spinning multi-component fibers from at least two different fiber forming spinning solutions. The solutions are extruded concurrently through a common orifice, being fed thereto through two narrow channels and into a common narrow channel. The thus formed composite stream is flowed through a continuous slit-like narrow channel which is separate from adjacent channels for other composite streams. The channel is sufficiently long so that the stream remains therein for at least 0.1 seconds. Thereafter the composite stream is extruded through a spinnerette to form composite filaments which do not delaminate.

Description

United States Patent Nakagawa et al.

1*Jan. 14, 1975 METHOD AND APPARATUS FOR SPINNING MULTICOMPONENT FIBERS patent subsequent to July 14, 1999, has been disclaimed.

Filed: Sept. 17, 1968 Appl. No.: 767,900

Related US. Application Data Continuation-in-part of Ser. No. 463,144, June 11, 1965, abandoned.

Assignee:

Notice:

Foreign Application Priority Data June 15, 1964 Japan 39-33823 US. Cl 264/171, 264/168, 264/182, 425/131 Int. Cl. B29f 3/10, DOld 3/00 Field of Search 264/182, 117, 174, DIG. 26, 264/168; 425/131 References Cited UNITED STATES PATENTS 10/1934 Jacquet 117/52 3,038,236 6/1962 Breen 264/171 3,195,865 7/1965 Harden I 25 /4 3,223,761 12/1965 Raley 264/171 3,239,197 3/1966 Tollar 259/4 3,318,987 5/1967 Fitzgerald 264/171 3,341,891 9/1967 Shimiza et a1. 264/D1G. 26 3,414,644 12/1968 Myles et a1. 264/168 3,416,982 12/1968 Petzetakos 264/171 X FOREIGN PATENTS OR APPLICATIONS 1,365,873 5/1964 France i 264/D1G. 26

520,000 3/1955 Italy I 264/D1G. 26 39-26141 ll/l964 Japan 264/D1G. 26

Primary Examiner-Jay H. Woo Attorney, Agent, or FirmWenderoth, Lind & Ponack 57] ABSTRACT A method and apparatus for spinning multicomponent fibers from at least two different fiber forming spinning solutions. The solutions are extruded concurrently through a common orifice, being fed thereto through two narrow channels and into a common narrow channel. The thus formed composite stream is flowed through a continuous slit-like narrow channel which is separate from adjacent channels for other composite streams. The channel is sufficiently long so that the stream remains therein for at least 0.1 seconds. Thereafter the composite stream is extruded through a spinnerette to form composite filaments which do not delaminate.

5 Claims, 4 Drawing Figures METHOD AND APPARATUS FOR SPINNING MULTICOMPONENT FIBERS This application is a continuation-in-part of application Ser. No. 463,144 filed June 11, 1965 now abandoned.

This invention relates to improvements in the production of multi-component, composite or conjugated fibers. More particularly, this invention relates to a method and apparatus for producing multi-component fibers wherein two or more different components are laminated or conjugated longitudinally of the fibers with an interface of junction area therebetween wherein these different components are sufficiently intermingled with or diffused into each other.

It is well known to produce multi-component fibers from at least two different fiber-forming spinning solutions by extruding them concurrently through a common orifice. Due to the difference in thermal shrinkage or swelling between these different materials of which such fibers are produced, coily crimps can be devel oped therein.

These known multi-component fibers, however, have the drawback that the components tend to be peeled off or delaminated. This tendency is more pronounced when the physical and chemical properties of the components are more different in order to improve the crimping characteristics. When the fiber components are thus peeled off or delaminated, the crimping characteristics are lost and the appearance of the finished product made of such fibers is adversely affected.

Therefore, it is an object of this invention to produce composite fibers wherein two or more components conjugate together firmly without danger of delamination thereof.

It has been found that this object is accomplished, according to this invention, by providing an intermediate orjunction area between the different components, the components being sufficiently intermingled with or diffused into each other in said intermediate or junction area. It is difficult to determine the exact area of such an intermediate or junction portion, but it has been found only a very small area, such as percent or less ofthe total cross sectional area of the fiber, is sufficient to substantially prevent the delamination of the components.

It has also been found that the necessary intermediate or junction area can be formed by interfacially contacting a spinning solution for one fiber component with another spinning solution for another fiber component in longitudinal laminations and maintaining the contact for a sufficient period of time before the solutions are concurrently extruded through spinning orifices for coagulation or solidification so that there occurs the desired intermingling or mutual diffusion in the interfacial (intermediate) or junction area. During the contact it is preferable to maintain the temperature as high as possible. For example, when the spinning solution is an aqueous solution, it is maintained at a temperature of 7090C.

It is believed that this blending of different spinning solutions at the narrow interfacial or junction area in the boundary area of the solutions is caused by thermal mutual diffusion between the molten or dissolved polymers, and therefore a prolonged period of contact of the solutions is most effective in producing the desired intermediate or junction area.

The period of time for keeping the interfacial contact of the spinning solutions required for producing the desired intermediate or junction area varies, depending upon the particular temperature of the system, polymer concentration and viscosity of the spinning solutions used. However, it has been found that the period of time of contact should be longer than 0.1 second, more preferably longer than 0.2 second.

To adjust the period of contact between the spinning solutions, the length of the spinnerette orifice can be altered. However, a sufficiently long orifice causes an unduly high back pressure. Moreover, as the volumes of the solutions being extruded are increased, the period of contact is reduced, and, consequently, the components are liable to be peeled off. And this problem of back pressure can not easily be solved simply by modifying the spinnerette orifice. The back pressure against the nozzle can be controlled to some extent by employing a specially designed spinerette orifice. Stated differently, only the discharge end of the orifice can be made the conventional size, and the diameter of the remaining portion of the orifice increased. For this purpose, however, there must be provided an additional variety of spinnerette orifices.

Thus, according to this invention, there is provided a spinning apparatus which comprises means for separately supplying a plurality of different spinning solutions, narrow channels for receiving each of said solutions, said narrow channels merging into a common narrow channel communicating with another slit-like narrow channel, said slit-like narrow channel receiving said solutions and communicating with orifices and being of such a length, in respect of the flow of said solutions, that the solutions are kept in contact for a sufficient time to form an intermediate area in the boundary layer of said solutions, wherein the solutions are sufficiently intermingled or mutually diffused, prior to being extruded through said orifices. In order that the lack of pressure not be unduly high, the width of the common narrow channel is from 5-10 times the diameter of the orifices.

The invention will be described in more detail by referring to the accompanying drawings wherein:

FIG. 1 is an exploded perspective view, partly broken away, of an embodiment of a device according to this invention, with various elements being disassembled;

FIG. 2a is an enlarged cross section, schematically represented, of the fiber showing delamination thereof;

FIG. 2b is a view similar to FIG. 2a, but showing another state of delamination; and

FIG. 3 is a view similar to FIG. 20, but showing the fiber of this invention having an intermediate or junction area.

Referring to FIG. 1, there is illustrated a spinning device for producing bi-component fibers according to this invention which comprises a plurality of partition walls 1 defining narrow longitudinal channels 2 within a cylindrical sleeve 3. The lower end portion of each partition wall is tapered to a V-shaped edge as shown. The inlet section of the cylindrical sleeve 3 is provided with a baffle 4 which serves to divide the inlet section into two

chambers

5 and 6. One spinning solution is supplied to the chamber 5 while the other is supplied to the chamber 6. The arrangement is such that the channels 2 are supplied alternately with these two different spinning solutions.

In association with the lower end of the sleeve 3 there is provided a guide plate 7 which has a corresponding number of Y-shaped channels 8. When assembled, each V-shaped edge of the partition wall 1 extends into the upper V-shaped groove of the corresponding channel 8 on the plate 7 defining a V-shaped channel merging into a straight channel portion 9 of the Y-shaped channel 8. The narrow straight channel 9 communicates with corresponding slit-like narrow channel 14 of guide disc 13. Said slit-like narrow channel 14 communicates with the corresponding orifices 10 of spinnerette 11, which is held in a cap assembly 12.

In operation, two different spinning solutions are supplied to the

separate chambers

5 and 6, respectively, and then forced into the channels 2 through which the solutions flow downwardly. At the top of the V-channel defined by the V-shaped edge and the upper V-shaped groove of the channel 8, the two different solutions are merged and flow together into the straight channel 9 in laminar flow with the adjacent faces of thin films of different solutions in interfacial contact; Then the solutions continuously and concurrently flow down through said slit-like narrow channel 14 and are extruded through the common orifices 10 into a conventional coagulating bath (not shown) wherein composite or conjugated fibers are formed. The construction and function of a spinning device of this type is more fully described in US. Pat. No. 3,182,106 of May 4, 1965, and reference should be made to the US Patent for further details.

The important feature of this invention resides in modifying, in relation to the flow rate of spinning solution, the said straight channel portion 9 so that the spinning solutions remain therein long enough to allow sufficient intermingling or mutual diffusion of the different solutions during the passage therethrough prior to extrusion through the orifices 10. As in the case where the flow rate of the spinning solutions is high, an intermediate guide disc 13 having a plurality of slit-like narrow channels 14 corresponding to and communicating at the upper end with the corresponding straight channels 9 and at the lower end with the corresponding orifices I0 is arranged to obtain a desired length of the

channels

9 and 14 necessary for producing the required intermingling or mutual diffusion of the solutions. The intermediate guide disc 13 may be made of a plastic or rubber material resistant to heat and chemicals.

In addition, a further important feature of the present invention is in properly dimensioning the common narrow channel so as to overcome various disadvantages of an incorrect back pressure in the intermingling or mutual diffusion area of the different spinning solutions, which proper dimensioning prevents the peel-off on delamination of fiber forming materials while retaining at least 0.1 second of contact time of said solutions to form an interfacial or junction area therebetween ahead of the spinnerette orifices.

This further important feature comprises making the dimensions of the passages for the spinning solutions and the orifices in the relation wherein d is the minimum diameter of the spinnerette orifices and D is the width of the common narrow channel communicating with said orifices, and adjusting the thickness of the guide plate and/or guide disc to give the required contact time for the volumes of the spinning solutions flowing therethrough.

[n the present invention, if the slit width is less than the abovementioned range, the back pressure of the spinning solution will be increased greatly and it will make it impossible to continue the spinning process.

On the contrary, if the slit width is wider than the said relation, no laminar flow of the spinning solution in the common narrow channel will be produced and the re sulting spun fibers will not have high resistance to delamination.

This invention will be further described in detail by way of the following examples, it being understood, however, that the scope of the invention is by no means limited thereto. All parts are by weight.

EXAMPLE 1 Two spinning solutions were prepared, respectively, from a copolymer A (intrinsic viscosity: 1.5 in DMF) consisting of parts of acrylonitrile and 10 parts of methyl acrylate and a copolymer B (intrinsic viscosity: 1.5 in DMF) consisting of 87 parts of acrylonitrilc, l3 parts of methyl acrylate and 0.5 parts of sodium allylsulfonate by dissolving each polymer in a 45 percent aqueous solution of sodium thiocyanate to obtain a solution of 10 percent by weight. The spinning solutions prepared as above were then fed at a predetermined rate to the equipment shown in FIG. 1, but not having an intermediate disc 13, and extruded in a coagulating bath comprising a 10 percent (by weight) aqueous solution (3C.) of sodium thiocyanate. The spinning solutions were maintained at a constant temperature of 80C., and the viscosity of each solution was 1,500 cp at that temperature.

The plate '7 used in this example had four channels, each straight channel 9 measuring 1 mm. in width and 1.3 mm. in depth. The spinning solutions after being merged were retained in the straight channel for a varying period (see Table l), and extruded through a spinnerette having a varying number of orifices so as to ob tain filaments of the same denier number. While the orifiees had a varying diameter from 1 mm. to 0.09 mm., the retention time of the solutions within the orifices was negligible.

The coagulated filaments were taken up at a rate of 50 meters per minute, and then washed with water thoroughly to remove the solvent. The washed filaments were stretched 10 times their initial length in hot water and dried over drying rollers, whereby 3-denier filaments were obtained.

To ascertain how the two components had been conjugated, the dry filaments prepared above were dyed with 4 percent (relative to fiber) of Aizen Cathilon Black (a cationic dyestuff by Hodogaya Chemical Co.,

Ltd.) in the conventional manner. Then, the dyed filaments were treated with saturated water vapor at C. for 20 minutes so as to allow the dye to diffuse sufficiently into the fiber structure, and the crosssection of each filament was studied under a microscope.

TABLE 1 Flow rate of spinning solutions (cc/min.) I5 30 45 60 75 Number of orifices 12 24 36 48 60 Contact time (sec) 0.42 0,2l ().l4 0.11 0.083 Delamination None None Partially Partially Almost all FIGs. 2a and 2b each shows the cross-section of the filament obtained by feeding the spinning dope at a rate of 75 c.c. per minute. It will be apparent that the two components are separated into two distinct sections, one of a lighter shade and the other of a darker shade, evidently showing delamination at the interface.

It may be concluded from the results of Table 1 that, in order to prevent such a delamination of the two components, the period of contact of the two spinning solutions before extrusion through orifice should be longer than 0.1 second and more preferably longer than 0.2 second.

EXAMPLE 2 The procedure of Example 1 was repeated with the exception that an intermediate guide plate 13 was made of Teflon sheet. The spinning solutions were extruded at a rate of 75 c.c. per minute. The thickness of the Teflon sheet was 6 mm. and the width of each channel was 1 mm. The intermediate guide plate 13 served to prevent leakage of the spinning dope between the spinnerette 11 and plate 7 and provided an additional retention time of 0.38 second for the contacted spinning solutions. The resulting filament was dyed in the same manner as Example 1, and the dyed filament microscopically studied. The cross-section of this filament is shown in FIG. 3, which indicates that the two components are firmly joined through an intermediate area where the two components are sufficiently intermingled.

What is claimed is:

l. A method of spinning multi-component fibers from at least two different fiber-forming spinning solutions by extruding them concurrently through a common orifice to produce a composite stream with the parts in interfacial contact, then flowing the thus formed composite stream through a continuous substantially uniform cross-section channel which is separate from adjacent channels for other streams of spinning solution for at least 0.1 second, said time being sufficient so that there is formed in the boundary layer of said spinning solutions, an intermediate area wherein the spinning solutions are sufficiently intermingled and diffused in each other to firmly join the different components in subsequently extruded filaments and thereafter extruding the composite stream through an orifice to form composite filaments.

2. A method as claimed in claim 1 wherein the contacting time is at least 0.2 second.

3. A method as claimed in claim 1 wherein the spinning solutions are maintained at a temperature of 90C. when the solutions are aqueous solutions.

4. An apparatus for spinning multi-component fibers from at least two different fiber-forming spinning solutions which comprises means for separately supplying a plurality of different spinning solutions, two narrow channels connected to the means for supplying the spinning solutions and respectively receiving the respective solutions, a common narrow channel into which said two narrow channels merge. another substantially identical and uniform cross-sectional dimension slit-like narrow channel into which said common narrow channel opens, said slitlike narrow channel receiving said solutions, and a spinnerette have orifices at the ends of said slit-like narrow channels and into which said slit-like narrow channels open directly, said slit-like narrow channels having a width I) in a relation to the minimum diameter d of the spinnerette of whereby said solutions are kept in interfacial contact for a period of at least 0.1 second so as to form an intermediate area in the boundary layer of said solutions wherein the solutions are intermingled and mutually diffused prior to being extruded through said orifices.

5. An apparatus as claimed in claim 4 in which said apparatus has a replaceable member in which said slitlike narrow channels are present whereby the member can be replaced with a like member of different size to change the length of the slit-like narrow channels.

Claims

2. A method as claimed in claim 1 wherein the contacting time is at least 0.2 second.
3. A method as claimed in claim 1 wherein the spinning solutions are maintained at a temperature of 70*-90*C. when the solutions are aqueous solutions.
4. An apparatus for spinning multi-component fibers from at least two different fiber-forming spinning solutions which comprises means for separately supplying a plurality of different spinning solutions, two narrow channels connected to the means for supplying the spinning solutions and respectively receiving the respective solutions, a common narrow channel into which said two narrow channels merge, another substantially identical and uniform cross-sectional dimension slit-like narrow channel into which said common narrow channel opens, said slit-like narrow channel receiving said solutions, and a spinnerette have orifices at the ends of said slit-like narrow channels and into which said slit-like narrow channels open directly, said slit-like narrow channels having a width D in a relation to the minimum diameter d of the spinnerette of 5d < or = D < or = 10 d whereby said solutions are kept in interfacial contact for a period of at least 0.1 second so as to form an intermediate area in the boundary layer of said solutions wherein the solutions are intermingled and mutually diffused prior to being extruded through said orifices.
5. An apparatus as claimed in claim 4 in which said apparatus has a replaceable member in which said slit-like narrow channels are present whereby the member can be replaced with a like member of different size to change the length of the slit-like narrow channels.