EP0195156A2

EP0195156A2 - Pre-oriented monofilament yarn manufacture

Info

Publication number: EP0195156A2
Application number: EP85306585A
Authority: EP
Inventors: Cesar Sumar
Original assignee: Individual
Current assignee: Individual
Priority date: 1985-03-21
Filing date: 1985-09-17
Publication date: 1986-09-24
Also published as: ZA86951B; EP0195156A3; MX162854B

Abstract

There is disclosed a process for manufacturing monofilament yarn of synthetic material, in which spinning material (3b) is hot extruded through a spinneret (2a) and downwardly through a cooling chamber (4) in which cooling air (A) is directed at the material (3b) to form it into filamentary form. Monofilament yarn is taken-up on a take-up device (9a), and a spin-finish oil emulsion is applied to the extruded material via nozzles 6 at a position close to the take-up device (9a). The take-up speed of the monofilament yarn is at least 4000 m/min, and this factor, in combination with the close arrangement of the nozzles 6 to the take-up device, enables monofilament yarn of the pre-oriented type to be obtained using otherwise conventional equipment of the type suitable for producing multifilament yarn, modified to carry out the process of the invention. The position of the nozzles 6 is at a spacing of between 2500 and 6500mm below the spinneret (2a).

Description

PRE-ORIENTED MONOFILAMENT YARN MANUFACTURE

This invention relates to the manufacture of pre-oriented monofilament yarn.
In the field of the techniques for manufacturing synthetic textile yarns, only the N.O.Y. (non-oriented-yarn) and M.O.Y. (medium-oriented-yarn) systems are currently used to produce monofilament yarns.
Thus, it has not been possible, until now, to use the P.O.Y. (pre-oriented-yarn) system for the manufacturing of monofilament yarns.
The difference between each one of the existing systems lies in the "take-up speed" of the yarn which is extruded in a plastic state (amorphous condition) from a spinneret, and in the "drawn grade" applied to the yarn.
The differences are shown in the following Table:
It is known that the P.O.Y. system offers greater advantages than the other systems, due to the higher take-up speed of the yarn, which results in a greater productivity of the machine, and due to the smaller residual stresses induced in the yarns, because of the smaller draw ratio to which the manufactured yarns are subjected to when using the P.O.Y. process. All of these factors result in a smaller number of ruptures on a predetermined length of manufactured yarn. This represents a better output and a better quality of the produced yarns. Moreover, an important increase in weight is obtained in the P.O.Y. yarn bobbins, in relation to the weight of smaller N.O.Y. or M.O.Y. yarn bobbins.
For some time, the manufacturers of synthetic textile yarns have recognized the potential convenience of producing monofilament yarns, using the P.O.Y. system; however, until now, it has been impossible to obtain monofilament yarns with an acceptable quality and with a high output (i.e. with a small number of breaks per 100 kms. of yarn) using the P.O.Y. process.
According to the invention there is provided a process for manufacturing monofilament yarn of synthetic material, comprisising hot extrusion, (in a spinning beam of conventional type used to produce multifilament yarns) of spinning material through a spinneret and downwardly through a cooling chamber in which cooling air is directed at the material to form it into filamentary form, taking-up monofilament yarn on a take-up device, and applying a spin-finish material to the spinning material at a position intermediate the spinneret and the take-up device :

characterised in that the spin-finish material is applied to the spinning material at a position close to the take-up device, and the take-up speed of the monofilament yarn is at least 4000 m/min, whereby monofilament yarn of the pre-oriented type (P.O.Y.) is obtained.

The invention will now be described in detail with reference to the accompanying drawing, in which:

Fig.l is a schematic side view, in section, which shows a spin beam apparatus for making P.O.Y. yarns of synthetic fibers, according to a known process; and
Fig.2 is a schematic side view, in section, which shows the apparatus of Fig.l, modified to provide a process according to the present invention for producing monofilament yarns by means of the P.O.Y. system.

- In Fig. 1, a conventional spin beam apparatus is used to manufacture yarns of synthetic fiber, for instance, polyamides, polyester or polyprolylene, and comprises a conventional extruder system 1 which ends in a spinneret 2 having several calibrated holes (not shown in order to clarify the drawing). These holes, in number of 2 or-more, have a diameter which are in the range between 0.15 and 0.30 mm. The apparatus of Fig.l may comprise a Zimmer spin beam, with a Barmag extruder and a conventional Cognosini take-up machine of the type used, up to now, only in the manufacture of multi-filament yarns.
The melted plastics material flows through the holes of the spinneret 2 and the filaments 3 (of which only four are shown),in an amorphous state flow downward through the inside of a cooling chamber 4 which receives a current of cooling air A, flowing through a diffuser screen 5, in order to cool the filaments and to produce the required crystallisation of the synthetic material.
As known in the art, several nozzles 6 (one for each filament bundle) are located at a certain distance below the spinneret 2, to provide each filament bundle with the required amount of a spin-finish emulsion.
As is known in the art, the nozzles 6 are located at a distance between 300 and 1700 mm below the spinneret 2 which, in turn, is positioned at a height in the range of 5000 to 8000 mm above a take-up device 9.
The filaments 3, after being moistened and gathered by the nozzles 6 continue moving downwardly, forming bundles in the inside of chamber 4 and, moving as a multifilament yarn 3a, through the inside of a tube 8, finally come out at the lower end 8a of tube 8.
The take-up device 9, of a constant take-up speed type (or of any other conventional type) takes up multi- filament yarn at a speed v in the range of 400 mts./min. or more.
Referring now to Fig.2, parts corresponding to those shown in Fig.l are designated by the same reference numerals, and will not therefore be described in detail again. In Fig.2, the spin beam of Fig.l is schematically shown from a side view, and includes modifications to produce monofilament yarns of the P.O.Y. type, using synthetic materials, such as polyamide 6 or polyamide 66, polypropylene or polyester.
The spinneret 2a has an area in the range of .600 - 1000 mm²and is provided with a single hole (not shown) with a diameter about 0.40 mm. The synthetic material is extruded through this hole, producing threads 3b (of which only 3 are shown) which descend along the inside of chamber 4, where they are cooled in a conventional way by means of the air flow A.
Threads 3b continue descending through tube 8, coming out at the bottom end 8a of tube 8.
Conventional thread guides 7a are located below the end 8a of tube 8, in order to receive threads 3b and guide them to corresponding take-up bobbins 9a.
In the several trials carried out with the apparatus, it has been found that the moistening of the monifilament yarns by means of the moisturizing nozzles (6), did not allow to produce a high quality yarn when moistening was performed in the conventional zone of application (between 300 and 1700 mm below the spinneret). Trials were performed, changing the location of the nozzles even farther away from the spinneret, and it was found that, when applying the spin-finish emulsion in an area adjacent to the bobbins 9a of the take-up device, that is to say, in a place below the bottom end 8a of the tube 8 of the apparatus, it was possible to produce a monofilament yarn at a take-up speed higher than 4000 m/min. i.e. a monofilament yarn of the P.O.Y. type.
The nozzles 6 are located, conveniently, between the bottom end 8a of the tube 8 and the location of the thread guides 7a, where the threads of P.O.Y. monofilament yarn change direction to enter the bobbins of the take-up device 9a.
The trials performed enabled the inventor to discover that the most convenient position for the nozzles 6, in order to moisten the P.O.Y. monofilament yarns with spin-finish emulsions, is located at a distance between 1500 and 2500 mm above the horizontal shaft of the take-up device 9a, that is to say, between 2500 and 6500 mm below the spinneret. Up to the present time, this has not been considered possible or practical with existing apparatus.
"The process feasibility and usefulness of the invention have been shown, using spinnerets with diameters ranging from 25 to 80 mm, each one having a single extrusion hole with a diameter ranging from 0.15 to 0.50 mm, and using emulsions with 4% to 20% of oil content (by weight), thereby obtaining P.O.Y. monofilament yarns, not only of polyamide 6 but also of polyamide 66, of excellent quality, with a low number of breaks (ruptures) per 100 kms of yarn and at take-up speeds of 4000 m/min or more.
The following Table illustrates some of the results obtained when producing monofilament yarns of the P.O.Y. type using the process of the invention, with several kinds of spinneret and different distances of the spin-finish nozzles (6) with respect to the spinneret. Also, the number of breaks in 600 kms of yarn (about 1 kg of yarn) and the proportion of oil (by weight) in the emulsion are shown.

Claims

1. A process for manufacturing monofilament yarn of synthetic material, comprisising hot extrusion, (in a spinning beam of conventional type used to produce multi- filament yarns) of spinning material (3b) through a spinneret (2a) and downwardly through a cooling chamber (4) in which cooling air (A) is directed at the material (3b) to form it into filamentary form, taking-up monofilament yarn on a take-up device (9a), and applying a spin-finish material to the spinning material (3b) at a position intermediate the spinneret (2a) and the take-up device (9a):

characterised in that the spin-finish material is applied to the spinning material (3b) at a position close to the take-up device (9a), and the take-up speed of the monofilament yarn is at least 4000 m/min, whereby monofilament yarn of the pre-oriented type (P.O.Y.) is obtained.

2. A process according to claim 1, characterised in that the spin-finish material is applied at a distance of between 2500 and 6500 mm below the spinneret (2a).

3. A process according to claim 1 or 2, characterised in that the spinneret has a surface area in the range 600 to 4000 sq.mm, and the or each extrusion hole in the spinneret has a diameter in the range 0.15 to 0.50 mm.

4. A process according to any one of claims 1 to 3, characterised in that the spin-finish material comprises a spin-oil emulsion containing from 4 to 20% of oil by weight.

5. A process according to any one of the preceding claims, characterised in that the synthetic material comprises polyamide, preferably polyamide 6 or polyamide 66, polypropylene, polyester or the like.

6. A synthetic pre-oriented monofilament yarn made by a process according to any one of the preceding claims.