US 3669591 A
Description (OCR text may contain errors)
June 13, 1972 E. FERMI ETAL 3,669,591
APPARATUS FOR PRODUCING COMPOSITE FIBERS Filed March 11, 1970 3 ShGGtS-Sh'it l IXVENTORS W ami June 13, 1972 E. EEEEEEE AL 3,669,591
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APPARATUS FOR PRODUCING COMPOSITE FIBERS Filed March 11, 1970 5 Sheets-Sheet} United States Patent Oflice 3,569,591 Patented June 13, 1972 3,669,591 APPARATUS FOR PRODUCING COMPOSITE FIBERS Enzo Fermi and Francesco Sassanelli, San Donato Milanese, Italy, assignors to Snam Progetti S.p.A., Milan, Italy Filed Mar. 11, 1970, Ser. No. 18,563 Claims priority, application Italy, Mar. 11, 1969, 13,914/ 69 Int. Cl. D01d 3/00 US. Cl. 425-131 6 Claims ABSTRACT OF THE DISCLOSURE A spinning head for melt spinning of composite filaments comprised of two polymers of equal semi-circular cross-section in which the mating faces of a distribution plate and a spinneret plate form two separate annular cavities each communicating with a different polymer supply contained in the distribution plate. A plurality of extrusion holes in the spinneret plate have their upper end portions of semi-circular cross-section communicating with one of the annular cavities and the remaining portions of circular cross-section communicating with the other annular cavity.
The present invention refers to new extruders suitable for obtaining composite fibers and filaments.
For many years, in the spinning technology of artificial and synthetic fibers, processes for obtaining composite fibers have been known which employ spinning devices consisting of knives for separating of the different polymers in the proximity of the extrusion zone. With these known devices, it is possible to divide two different polymers into two generally concentric circular zones, each of them being situated near the extrusion orifices.
The aforementioned known spinning devices have, however, been subject to several drawbacks. In particular, difficulty has been encountered in the field of melt spinning in obtaining composite filaments having perfectly evenly divided cross-sections of conjugated polymers.
It is therefore an object of this invention to provide a new and improved apparatus for forming composite fibers and filaments.
Another object of this invention is to provide, in a new and improved apparatus for forming composite fibers and filaments, a spinneret plate which is of simplified construction and utilization.
Briefly described, the foregoing objects of the present invention are attained by providing a spinneret plate which consists of a single piece, thereby reducing sealing difficulties which are generally encountered in conventional spinning heads, which require two spinneret plates for forming conjugated fibers. The extrusion orifices of the spinneret plate are partially semi-circular and partially circular in cross-section and receive the two polymers at different points, so that the first polymer is shaped into a semi-circular cross-section before the second polymer is introduced to the portion of the extrusion holes having a circular cross-section. Practically, it is preferable that the semi-circular cross-sectional portion of each of the extrusion holes extends for at least 2 mm. The polymer distribution plate is an integral part of the apparatus in that the possibility of employing the spinneret plate for forming bicomposed filaments depends on its lower face being shaped so as to mate perfectly with the upper face of the spinneret plate.
The accompanying drawings, referred to herein and constituting a part hereof, illustrate preferred embodiments of the invention and, together with the description, serve to explain the principles of the invention.
FIG. 1 represents a cross section of spinneret plate B and distribution plate A constructed according to the present invention.
FIG. 2 is a top plan view of the spinneret plate according to FIG. 1.
FIG. 3 shows a cross section of another spinneret plate 1) and distribution plate C, according to the present invention.
4 is a top plan view of the spinneret plate of FIG. 5 is a photographic reproduction of an assembly according to the invention.
Obviously the above figures are only intended to illustrate but not to restrict the invention itself.
With reference to the above figures the hollow chamber 1 and 2 of distribution plate A contain two different polymers which, through the fares 3 and 4, respectively, are fed through the annuluses 5, 7, respectively, to the extrusion holes 8. As best seen in FIGS. 1 and 3, the polymer contained in chamber 1 enters extrusion hole 8 at a point 9 where it is semi-circular in cross-section and the polymer contained in chamber 2 of the distribution plate enters the extrusion hole 8 at a point where it is circular in cross-section.
Essentially the extrusion device suitable for manufacturing bicomposed fibers according to the invention consists of a spinneret plate and a distribution plate and is characterized in that the feeding of two different polymers takes place at different levels with respect to the spinneret extrusion hole. One of the polymers is fed to the extrusion hole at a point where its cross-section is semi-circular in shape so as to be formed into a semicylindrical profile before reaching the portion of the extrusion hole which has a circular cross-section, where the other polymer is introduced.
The cross-section of composite fibers obtained with spinning apparatus constructed according to the invention presents a very sharp and substantially straight separation line between the two components. In addition, it has been found that a spinning head constructed according to the invention permits the distribution plate to be shaped so as to enable the unit to be sealed both on the external periphery thereof and also on its central zone which contacts the spinneret plate. Also, as previously mentioned, the distribution plate allows the distribution of different polymers in two different points of the spinneret plate extrusion holes by using the semi-circular cross section of the hole formed by the distribution plate for feeding a first polymer thereto and feeding the other polymer at another half of the hole in the point where the complete circular cross section is reinstated.
The invention in its broader aspects is not limited to the specific embodiments herein shown and described but departures may be made therefrom within the scope of the accompanying claims, Without departing from the principles of the invention and without sacrificing its chief advantages.
1. A spinning head for melt spinning of composite filaments or the like, including a spinneret plate;
said spinneret plate including a plurality of extrusion holes, each of said extrusion holes including a first portion of semicircular cross-section, and a second portion of circular cross-section; a distribution plate including a first chamber, a first passageway extending out of said first chamber,
a second chamber, and
a second passageway extending out of said second chamber; first annular cavity means being defined by said spinnert and distribution plates and communicating said first passageway extending out of said first chamber 5 with said first semi-circular portions of each of said extrusion holes; and second annular cavity means being defined by said spinneret and distribution plates and communicating said second passageway extending out of said second chamber to said second circular portions of each of said extrusion holes. 2. A spinning head as claimed in claim 1, wherein said spinneret plate is formed on one face thereof with a first annular rib member; said distribution plate is formed on one face thereof with a first annular recess communicating with said first passageway,
said first annular recess adapted to telescopically slida-bly receive a portion of said first annular rib member formed on said spinneret plate so as to form said first annular cavity means; said distribution plate having further formed on said one face thereof a second annular recess opening at one side into said first annular recess 5 and communicating with said second passagey, said second annular recess adapted to form with said one face of said spinneret plate said second annular cavity means; and said extrusion holes are formed in said spinneret plate so that their central axes are in registry with the inner edge of said first annular rib member,
whereby the inner side wall of said first annular recess forms said first semi-circular portion of 35 said extrusion hole. 3. A spinning head a claimed in claim 1, wherein said semi-circular cross-sectional portion of each of said extrusion holes extends for a length of at least 2 mm.
4. A spinning head as claimed in claim 2, wherein said first annular rib member is stepped along the inner circumferentially-extending edge thereof; and
4 said spinneret plate has an annular step formed opposite said second annular recess in said distribution plate and extending along the outer portion thereof; whereby said first and second annular cavity means each include narrowed portions adjacent said extrusion holes. 5. A spinning head as claimed in claim 2, wherein said first annular recess is bounded on its outer edge by the peripheral portion of said distribution plate so as to form a circumferentially-extending outer rib; and said spinneret plate includes a circumferentially-extending groove adjacent said first annular rib member and extending along the peripheral edge of said spinneret plate,
whereby said circumferentially-extending outer rib member of said distribution plate is adapted to sealingly mate with said circumferentiallyextending peripheral groove on said spinneret plate. 6. A spinning head as claimed in claim 5, wherein said distribution plate includes a central portion in wardly of said second annular recess adapted to sealingly engage said spinneret plate.
References Cited UNITED STATES PATENTS 3,017,686 1/1962 Breen et a1 264-477 FX 3,075,241 1/1963 Dietzsch et al 188 SC 3,188,689 6/1965 Breen 18-8 SC FOREIGN PATENTS 1,101,452 1/1968 Great Britain 18-8 SC I. SPENCER OVERHOLSER, Primary Examiner M. O. SUTTON, Assistant Examiner US. Cl. X.R.
Patent No. 3,669,591 Dated June 13, 1972 Inventor(s) Enzo Fermi and Francesco Sassanelli It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:
Signed and sealed this 19th day of March 19774..
EDWARD M.FLETCHER, JR. C. MARSHALL DANN Attesting Officer Commissioner of Patents Column 1, line 32, after "separating" delete of Column 2, line 17, change "fares" to read bores line 50, change "another" to read other Column 3, line 37, after "head" change "a" to as FORM PO-1050 (10-69) USCOMNFDC corned a u.s. sovlmmnn rnnmna ovncz: n0 o-au-a