US 3439085 A
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Description (OCR text may contain errors)
United States Patent Int. (:1. D01f 7/56,- D06m 3/24 U.S. Cl. 264210 4 Claims This application relates to the production of filament material, and more particularly to the production of fabrics from filaments, especially non-woven fabrics.
This application is a continuation-in-part of application Ser. No. 341,489, filed Jan. 27, 1964, and the disclosure of the said co-pending application is incorporated herein by reference.
Ser. No. 341,489 discloses a process for spinning of filaments which comprises issuing a fused polymer mass in the form of filaments from several linear rows of spinneret holes of a spinneret head, and directing gas streams into impinging and entraining relation with the issuing fused polymer filaments to draw them and orient polymer molecules in the direction of the filament axis. The mass is drawn to reduce the diameter from the diameter of the spinneret hole in the ratio of at least 30:1, and the filaments are cooled to a set condition wherein the molecular orientation is retained. The filaments are maintained in drawn condition during the cooling by gas streams directed against the filaments to urge them to the drawn condition. In practical application, a multitude of linear, parallel filament rows are simultaneously drawn while keeping them in parallel arrangements within separate air channels, and the drawn and set filaments of the dilferent rows are finally collected on a screen or perforated roll for the formation of a fleece or mat.
It has now been found that the process of Ser. No. 341,489 can advantageously be utilized in the production of filaments from polyurethane. If a melt of polyurethane which is not cross linked or not completely cross linked is utilized in the process, and cross linking is permitted to occur during the drawing of the fused polymer issuing from the spinneret head, filaments, and in turn fabrics, characterized by uniformly high elasticity are obtained. Macro diisocyanate polyesters or polyethers containing glycols or diamines in an amount desirable for the intended cross linking, can be used. The moisture present in the air which is blown along the path of the fused polymer can be relied upon to cause the cross linking to occur.
Apparatus as is disclosed in Ser. No. 341,489 can be used in the practice of the instant invention. Thus, apparatus as is shown in Fig. of the drawing of the prior application can be used. Accordingly, the apparatus can include a plurality of parallel disposed nozzles, each having in excess of 100 holes of about 0.4 mm. diameter at a spacing of 2 mm., in a straight line. An air slot of 0.3 mm. width can be provided on each side of each line of spinneret holes at a spacing of 0.5 mm. from the line of holes. The nozzles can be heated to the temperature of the polyurethane melt or to the desired reaction temperature, and air heated to the same temperature can be blown through the slots to provide the desired drawing of the fused polymer. The air velocity leaving the slots is at least five times greater than the velocity of the threads issuing from the spinneret holes. The nozzles can be spaced about 60 mm. apart. At least about mm.
3,439,085 Patented Apr. 15, 1969 from the nozzles, in the direction of advance of the fused polymer, guide passageways are disposed. There is a guide passageway for each nozzle made up of a plate disposed above the plurality of filament forms and a plate disposed below the filament forms; the spacing of the plates is about 50 mm., and the passageway is 600 mm. in length (in the direction of travel of the filaments); the passageways terminate in the lateral direction about 10 mm. from the outermost filament form on each side. Air can be injected into the passageway through the plates, the air being injected from above and below the filaments. If desired, the guide passageways can be moved as is indicated in Fig. 8 of Ser. No. 341,489, in a rocking motion, to impart a corresponding movement to the filaments. The filaments can be collected on a drum or conveyor as is disclosed in Ser. No. 341,489.
If desired, filaments of different composition can be combined in a single fleece, using different nozzles for the different filament compositions. For example, a fabric could be formed of polyurethane and polyamide fibers.
The fibers when they are deposited on the collecting means wherein they are gathered into a fleece, can be in such condition that bonding of filaments occurs at filament crossing points. In this manner a bonded fleece can be obtained without the addition of binding agents. Such processing finds application where the fibers are all polyurethane polymer, and also where the fibers are mixtures of filaments of different composition, such as polyurethane and polyamide.
The invention is further described in the following examples.
Example 1 A granular polymer composition of parts of a condensation product of adipic acid ethylene glycol polyester and diphenyl methan-4,4'-diiso-cyanate, partially crosslinked with 30 parts butane-1,4-diol was melted in a wormpress at a temperature of 180 C. and supplied at a temperature of 200 C. to four spinning pumps. The spinning-pumps conveyed the melt to four spinning nozzles opening downwardly and heated to 205 0, arranged parallel to one another at a distance of 80 mm. apart. Each of the spinning-nozzles consisted of a straight line of holes of 400p. diameter, spaced apart 2 mm. so that each of the four longitudinal nozzles had a straight row of holes of 320 mm. length. An air slot was positioned on both sides of each line of holes. The slots were 3 mm. x 340 mm. length, and were spaced .5 mm. from the holes. Air heated to 205 C. with a pressure of 0.8 atmosphere gauge was supplied to the slots so that from both slots a band-shaped air-stream of about 340 mm. width issued. From the row of holes, in turn, issued a series of still melted polyurethane filaments, which at both sides were pulled forward by the band-shaped air streams, issuing with a velocity of about 5000 m./min. Therein the filaments were drawn from a cross-section of 400 to about 30;/.. Since the filaments were very viscid, and would upon touching at once stick together, turbulence formed through friction of the adjacent air-layers, had to be excluded. For this purpose, the thread group of each nozzle, together with the band-shaped air currents enveloping it was introduced into elongated guide-channels, which were spaced 20 mm. from the nozzle bore holes. The air channels had the following interior-measurements: 50 mm. plate distance, 340 mm. width, 600 mm. length. Additionally, the inner-walls of each air channel were rinsed with further cold air-streams, with the aid of two air slots of 0.3 mm. slot-height in each wall, disposed at the inlet and outlet side. The slots were at an angle of 10", so that an air rinsing impinged tangentially to the fiber flying direction. The pressure used for the rinse air was 3 atmospheres gauge on the slots. Through these measures it was possible to prevent a mutual entangling as well as touching of the individual filaments of each group. Since each individual nozzle had a channel allotted to it, the entangling of the threads of adjacent nozzles was not possible. The fleece formation took place after the filament left the air channels. The fibers and air-streams were separated with the aid of a screen through which suction was applied. The screen was mounted at a distance of 700 mm.
. from the outlet end of the air-channels. The matting of the Example 2 The apparatus of Example 1 was used, but nozzles 1 and 3 were supplied with the above-described polyurethane, and nozzles 2 and 4 were supplied with polycaprolactam. The Working conditions of the nozzle 2 and 4 were as follows: nozzle temperature 230 C., air temperature 230 C. The fleece formed contained, in the ratio 1:1, endless polyurethane and polyamide filaments, bonded together at crossing points.
Whereas in the examples, moisture in the air is relied upon to cause the cross linking which occurs during drawing of the filaments, any other known suitable means can be relied upon for providing the cross-linking conditions. In general, air at ambient conditions is suitable for the purpose.
What is claimed is:
1. Process for the production of non-woven elastic fabric, which comprises fusing a cross-linkable polyurethane mass; melt-spinning said fused mass into a multiplicity of substantially endless filaments; air-drawing said substantially endless filaments while maintaining said filaments in a hot and tacky state, whereby the molecules of said filaments are oriented in the direction of the axis of said filaments; laying said hot, tacky oriented substantially endless filaments on a supporting surface; cross-linkin-g said substantially endless filaments by means of moisture in said air; and welding said substantially endless polyurethane filaments to other such filaments by means of its tackiness, wherein said filaments become solid and non-tacky after said welding.
2. Process according to claim 1, wherein simultaneously a second polymer of different composition from said first-mentioned polymer is drawn into filaments in like manner, and the filaments of both polymers are collected together to form the fleece.
3. Process according to claim 1, wherein the filaments solidify after collection thereof in crossing relation and become bonded together at crossing points during the solidification.
4. Process according to claim 2, wherein the polyurethane filaments solidify after collection of both polymers in crossing relation and upon solidification filaments become bonded together at crossing points.
References Cited UNITED STATES PATENTS 2,810,426 10/1957 Till et al. 51-295 3,026,190 3/1962 McMahon et a1. 51-295 2,336,745 12/ 1943 Manning.
2,869,973 1/1959 Hubbard 16l--170 3,117,055 1/1964 Guandique et a1. 161170 3,154,611 10/1964 Dinber'gs 2 64176 3,158,525 11/1964 Reynolds 161-170 3,199,281 8/1965 Maerov et al 264210 2,411,660 11/1946 Manning 264176 DONALD J. ARNOLD, Primary Examiner.
US. Cl. X.R.