US3540077A - Apparatus for spinning multi-component fibers - Google Patents

Description

Nov. 17, 1970 KAZUMI NAKAGAWA ETAL 3,540,077

APPARATUS FOR SPINNING MULTI-COMPONENT FIBERS Filed Dec. 30, 1968 I nvehlor Aflorny$ States US. Cl. 18-8 1 Claim ABSTRACT OF THE DISCLOSURE A method and apparatus for spinning multi-cornponent fibers from at least two different fiber-forming materials. The fiber-forming materials are caused to flow toward each other through narrow channels in a spinning apparatus which bring the materials together at an angle of 180 and cause the materials to collide with each other with an increased flow velocity to create a turbulent flow for intermingling the materials at the interface be tween them. The materials are than caused to flow in laminar flow through a common passage and then through a series of orifices at the end of the common passage. The intermingling of the two materials at the interfacial area prevents delamination of the fiber.

This application is a continuation-in-part of application Ser. No. 467,510, filed June 28, 1965, and now abandoned.

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

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

These known multi-component fibers, however, have a drawback, namely that the components of the fibers tend to peel away from each other or become delaminated. This tendency is greater when the physical and chemical properties of the components are made more different in order to improve the crimping characteristics. When the fiber components are peeled apart or "because delaminated, the crimping characteristics are lost and the appearance of a final 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.

atent It has been found that this object can be accomplished, according to this invention, by providing an intermediate or junction area between the different components, the components being sufficiently intermingled or blended with each other in said intermediate or junction area. It is diifcult to determine the exact area of such intermediate or junction portion, but it has been found that only a very small area, such as about 10% or less of the total cross sectional area of the fiber, is sufficient to substantially prevent the delamination of the components.

It has also been found that such an intermediate or junction area can be formed by causing the flows of the different spinning solutions to collide with each other before they flow toward and through an orifice in laminar flow so that when the different solutions meet or collide with each other there is created a turbulent flow which causes the formation of the intermediate or junction area wherein these solutions are well blended or intermingled. In order to obtain the necessary turbulent flow, it is necessary that these different spinning solutions collide with each other at an increased velocity of flow and at an obtuse angle, preferably According to this invention there is provided an apparatus to create the desired turbulent flow. Thus, according to this invention, there is provided a spinning apparatus which includes means for separately supplying a plurality of different spinning solutions, a first narrow channel for receiving each of said solutions, said first narrow channels merging through second narrow channels into a common narrow passage which is separate and spaced from adjacent similar passages and communicating with a row of spinning orifices, said second narrow channels being narrower than the first narrow channel and meeting at an obtuse angle and opening into the said common passage, so that the different spinning solutions flowing through the respective first and second narrow channels collide with each other at an increased velocity of flow when discharged from the second narrow channels to create a turbulence and then flow in a laminar flow having an intermediate blended area through the common passage and orifice into a coagulating bath. If desired, an enlarged space may be provided at the area where the second narrow channels meet or merge so that the solutions which have collided with each other will stay in the enlarged space for a while so as to further promote the interfacial intermingling or blending.

The invention will be described in more detail with reference to the accompanying drawings wherein:

FIG. 1 is a longitudinal section of a device embodying the invention;

FIG. 2 is a section of the same device taken along line A-A of FIG. 1;

FIG. 3 is an enlarged view of a part of FIG. 1;

FIG. 4 is a view similar to FIG. 3, but showing another embodiment of the invention;

FIG. 5 is a view taken on the line BB of FIG. 3 or FIG. 4; and

FIG. 6 is an enlarged cross-sectional view, schematically represented, of the fiber obtained by the invention.

Referring to FIGS. 1 and 2, there is illustrated a spinning device for producing bi-component fiber according to this invention, which comprises a spinerette plate 2 having orifices 1 arranged in rows spaced from each other. The plate 2 is mounted on a guide plate 4 having the same number of passages 3 as there are orifices 1, the passages also being in rows. The plates 2 and 4 are held against the end of a sleeve 5 at the end of supply tube 8 by means of a cap 6 and nut 7. The inlet section of the cylindrical sleeve 5 which is inserted and held in the supply tube 8 is provided with a bafile 15 which serves to divide the inlet section into two chambers 9 and 10 (FIG. 2). One spinning solution is supplied to the chamber 9 while the other is supplied to the chamber 10. The outlet section of cylindrical sleeve 5 is provided with a plurality of narrow channels 12 and 12' defined by partition walls 11. The arrangement is such that the channels 12 and 12 are in communication with the chambers 9 and 10 in such a way that alternate channels are supplied with the different solutions. In operation, the first spinning solution flows from one chamber 9 to alternate channels 12 and down into the associated passage 3 toward orifices 1. The second spinning solution flows from the other chamber 10 to alternate channels 12' and also down into the associated passage 3. In the common passage 3, which is separate from and spaced from similar adjacent passages, the two different solutions flow in laminar flow down to the roW of orifices 1 and then into a coagulation hath (not shown) to form composite fibers. The construction and function of a spinning device of this type is more fully described in U.S. Pat. No. 3,182,106 of May 4, 1965, and reference should be made to this patent for further details.

The important feature of this invention resides in making a special arrangement between the narrow channel 12 and 12' and common passage 3 to create a turbulent flow therebetween. As shown in FIG. 3, the lower flat end of each partition wall 11 and the upper flat surface of the guide plate 4 are spaced from each other and define narrow clearances or passages 13 and 13' so that a high velocity (high rate of flow) is imparted to a solution flowing through these narrow clearances or passages. Furthermore, the channels 13 and 13 should be at an obtuse angle, preferably 180, as shown in FIG. 3. The dimension of these clearances should be such that the flow through the passage 13 and the fiow through the passage 13 collide violently, forming partly intermingled or blended area. For this purpose, it is preferable that the clearance be as small as possible. However, if the clearance is too small, the flow resistance will increase as the flow velocity increases so that an unduly high pressure is required to effectively feed and flow the liquid through the spinnerette device. It has been found that the relation between W (distance between adjacent partition walls 11) and w (clearance 13 and 13) should satisfy the following formulas:

Then the two solutions flow in laminar flow (with an intermediate or junction area where the two are intermingled or blended) down through the common passage 3, which is separate from and spaced from similar adjacent passages, to the row of orifices 1.

In another embodiment of the invention shoWn in FIG. 4, there is formed a recess 14 at the end of the partition wall 11. In this case, the solutions flow toward each other through the respective narrow channels or clearances 13 and 13' and merge in the recess where they intermingle before they flow into the common passage 3 in laminar flow. During the turbulent flow in said recess the solutions intermingle or blend partly at the interface. The dimensions of the channels 13 and 13 relative to the width of channels 12 and 12' are the same as in the embodiment of FIGS. 1-3.

Since a turbulence is created, according to the invention, at the interfacial area. between the different solutions, there is formed between the solutions an intermediate or junction area where the solutions are well intermingled or blended. The solutions in this condition then flow through the passage 3 in laminar flow with said intermediate area therebetween and down through the orifices 1 into a coagulating bath (not shown) so that there are formed composite fibers having the corresponding intermediate portion through which the two different fiber components are bonded firmly without a danger of peel-off or delamination, as shown in FIG. 6.

This invention can be applied not only to a wet spinning process, but also to a melt spinning process. The invention is applicable to spinning of any fiber-forming material such as acrylonitrile polymers, polyamides, polyesters, polyvinyl chlorides, polyvinyl alcohols, polyolefins, cellulose acetates, viscose, etc., so far as the production of multicomponent fibers is concerned.

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

EXAMPLE Two spinning solutions were prepared, respectively, from a copolymer A (intrinsic viscosity 1.5 dl./g. in DMF) consisting of parts acrylonitrile and 10 parts methyl acrylate and a copolymer B (intrinsic viscosity 1.5 dL/g. in DMF) consisting of 87 parts acrylonitrile and 13 parts methyl acrylate, by dissolving each polymer in a 45% aqueous solution of sodium thiocyanate to be a 10% solution.

These two spinning solutions prepared as above were spun through the spinning device, as shown in FIGS. 1-3, wherein W was 1 mm. and w was 0.2 mm. The solutions were spun into a coagulating bath comprising a 10% by weight aqueous solution (-3 C.) of sodium thiocyanate to form composite fibers.

In order to observe how the two components had been conjugated, the dry fibers prepared above were dyed and heat treated so as to allow the dye to dittuse sufiiciently into the fiber structure. Then the cross-section of the fiber was observed under a microscope. There was observed no sharp distinction at the border between the two components, but an ambiguous interfacial or intermediate area where two components were intermingled or blended, as shown in FIG. 6.

The same procedure was repeated with the spinning device of FIG. 4 and a similar result was observed.

In each case, the fibers were spun into yarns, which were then knitted into a fabric. However, no delamination of the fiber components was seen during the mechanical processing. When heat treated in a conventional manner, the yarns developed very satisfactory coily crimps.

What is claimed is:

1. An apparatus for solution spinning multi-component fibers from at least two different fiber-forming materials which comprises means for separately supplying a plurality of different fiber-forming materials; a plurality of spaced partition walls defining between them at least two separate first narrow channels having a width W, said channels being connected at one end to said means for receiving the respective materials therefrom; a guide plate opposite the ends of said partition walls at the other ends of said channels and spaced from said partition walls a distance w to form further narrow channels opening out of the other ends of said first narrow channels, the relation between W and w being w 0.1 (mm) said further narrow channels meeting each other and joining at an angle of and said guide plate having at least one common passage therein having at least one orifice at one end thereof and having the other end open- 5 6 ing into said second narrow channels where they meet, 3,350,741 11/1967 Yoshida et a1. said end of said partition wall opposite said common 3,403,422 10/1968 Nakagawa et a1. 264l71 X passage having an enlarged space at the area where the 3,469,279 9/1969 Hudgell 264-171 X second narrow channels meet, and opposite said co m- FOREIGN PATENTS mon passage so that the fiber-formmg materials WhlCh 5 collide with each other intermingle in said space before 7601179 10/1956 Great Bfltalnflowing into said common passage so as to further pro- 1,442,690 12/1966 Framemote the interfacial blending. 3946441 11/ 1964 Japan- 6,412,113 4/1965 Netherlands.

References Cited UNITED STATES PATENTS 2,936,482 5/ 1960 Kilian. 3,192,562 7/1965 Powell. US 3,289,249 12/1966 Nakagawa et a1. 15 264171 19 JULIUS FROME, Primary Examiner J. H. WOO, Assistant Examiner

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