Process for producing a combination yarn using independent filaments

Abstract: A description is given of a process for producing a combination yarn (5) composed of at least two filaments (1, 3), of which at least one (3) is textured, the said filaments (1, 3) being united inside a double-twist spindle (2), in which process at least one (3) of the said filaments (1, 3) undergoes texturing in a unit (4) located upstream of the said double-twist spindle (2), the direction of the false twist imparted to it in the course of texturing being independent of the direction of the real twist inserted by the abovementioned double-twist spindle (2).

Description: The present invention relates to the textile industry, and more especially that part thereof which is occupied with the production of so-called "combination" yarns, that is yarns composed of two or more filaments of dissimilar type and/or material united by suitable processes. These yarns may be smooth or "textured", and the inventor of the process that forms the subject of the present application has by its means greatly improved textile technology, especially in the field of textured yarns. As those skilled in the art know, texturing is the term applied to an operation of twisting a filament by false twist with simultaneous exposure of the twisted length to a source of heat. At the end of the texturing process a filament acquires volume and elasticity that have beneficial effects on the thickness and elasticity of a fabric made from the yarn, and on the tactile sensation which the fabric offers when used e.g. to make garments. One particularly well-known and popular yarn known as "Situssa" is composed of two filaments, one of which, with a percentage weight of approximately 30% of the total, is of nylon while the other, with a percentage weight equal to the remaining approximately 70%, is of acetate. The yarn in question is textured after its two component filaments have been united and optionally twisted, by varying processes including those described in Italian patents No. 1.283.948 and No. 1.276.186 by the same applicant or other processes of different kinds. Referring particularly to the abovementioned patent applications, the yarn is made by covering one or more core filaments by spiralling one or more covering filaments around them inside a double-twist spindle, after the covering filament has already optionally undergone a further twisting on another spindle. In the present state of the art the yarn, following the joining of its component filaments, undergoes texturing in which it is given a false twist and passes through an oven in which it is heated. Staying with the processes of the abovementioned applications, the real twist and the apparent twist imparted to the components of the yarn by the double-twist spindle have the same direction, and still have the same direction even during subsequent texturing. The handle and aesthetic appearance of the final product are therefore limited, in the sense that they cannot be varied in multiple ways, which limits the variety of yarns that can be obtained. This fact represents a major limitation caused by the fact that the said directions are necessarily the same as each other and that all the components of the yarn necessarily pass through the texturing unit. The inventor of the present invention has devised a new process in which at least one of the filaments to be covered is textured before entering the double-twist spindle, where it is joined with a twisted covering filament. The direction of the real twist inserted into the yarn inside the double-twist spindle may thus be the same as or opposite to the direction of the false twist imparted to the "core" filament during the previously described texturing process, depending on the "body" or volume and handle which it is desired to give the yarn. This is because when the said two directions are opposed, the yarn assumes a handle, a volume and an elasticity that are unachievable in the processes hitherto employed. More specifically, the subject of the present invention is therefore a process as described in the preamble of the attached Claim 1 and as characterized by the characterizing part of the same claim. A more detailed description of the process according to the invention will now be given, reference also being made for the sake of clarity to the attached figure, which shows diagrammatically a spinning unit that carries out the process according to the invention. As the figure shows, a covering filament 1, optionally pre-twisted, and textured or not textured, is fed into a double-twist spindle 2, where it is wound in a spiral around a core filament 3 which has already been textured in a unit 4 which, as already explained, has given it a false twist. The two filaments 1, 3, thus united, leave the double-twist spindle 2 in the form of a yarn 5 of which component 1 has been subjected to a real twist in the said spindle 2 whose direction may be the same as or dissimilar to that of the false twist imparted to the core filament 3 or to the cover filament 1 in the course of the previous transformations. This has achieved the desired result, which was to make a combined yarn from a plurality of independent filaments, in a sense that one or more of these can be subjected to texturing independently of the others. One or more of them (the core filaments and cover filaments) can therefore be given texturing with directions of false twist selected in whatever way may be desired, that is to say the same or opposite directions and individually the same as or opposite to that of the real twist imparted by the double-twist spindle when they are being combined. Variations of the process are possible without departing from the scope of that which is expressed in the attached Claim 1 and consequently without departing from the scope of patent protection conferred by the present application.

Claims: Process for producing a combination yarn (5) composed of at least two filaments (1, 3), of which at least one (3) is textured, the said filaments (1, 3) being united inside a double-twist spindle (2), the process being characterized in that at least one (3) of the said filaments (1, 3) undergoes texturing in a unit (4) located upstream of the said double-twist spindle (2), the direction of the false twist imparted to it in the course of texturing being independent of the direction of the real twist inserted by the abovementioned double-twist spindle (2).

Inventors: RATTI ARTURO, RATTI, ARTURO
Applicants: ARRATEX SRL, ARRATEX S.R.L.
Application year: 1998
Main classification: D02G1
IPC codes: D02G1, D02G3