The present invention is directed to a yarn, especially a sewing yarn.
A plurality of yarns with different constructions as well as corresponding methods of producing the same are known. So, on principle such yarns can be spun from multifilament fibers, from staple fibers or from a mixture of multifilament fibers and staple fibers, wherein such a yarn can be additionally threaded in order to improve the thread cohesion and thus the durability of the yarn with regard to mechanical stresses.
In the field of application of the sewing yarns often threads are used consisting of at least two, normally multifile yarn components, wherein these two yarn components threaded with one another are equally formed not only with regard to the number of elementary threads and the titre but also with regard to the strength (tensile strength).
Furthermore, yarns, especially also sewing yarns, are known which have been formed from at least two multifile yarn components, wherein, for the manufacture of such a yarn, the two yarn components are intermingled with one another by means of a fluid stream such that the first yarn component is mainly located within the core of the spun yarn and is thus also designated core component, while the second yarn component is mainly located in the outer area of the spun yarn and is thus designated jacket component or covering. In such core-jacket-yarns the jacket component has a significantly greater length which has the result that the jacket component (covering) gives such a core-jacket-yarn a certain volume since slings, self-crossing loops and/or arcs are formed. Normally, these core-jacket-yarns have excellent characteristics with regard to the mechanical durability so that they are more and more used for sewing yarns which are exposed to extreme mechanical stresses during their processing.
In order to attain the necessary strength with the above-described yarns German disclosure letter 3 834 139 suggests to form the core yarn component and the jacket yarn component of the same ultra-strong material. Here, the specific strength (tensile strength) of the multifile core yarn component and of the multifile jacket yarn component amounts to at least 40 cN/tex, preferably more, according to German disclosure letter 3 834 139.
The present invention is based on the problem to provide a core-jacket-yarn of the cited kind which has an especially good mechanical durability.
USPTO Backgrounds
USPTO Backgrounds