[0001] 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.
[0002] 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.
[0003] 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.
[0004] 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
patent applications No. RM 96A 000139 and No. RM 95A 000 622 by the same applicant
or other processes of different kinds.
[0005] 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.
[0006] 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.
[0007] 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.
[0008] 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.
[0009] 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.
[0010] 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.
[0011] 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.
[0012] 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.
[0013] 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.
[0014] 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.
[0015] 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.
1. 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).
