The present invention relates to a yarn with the appearance of a spun yarn, made from polyamide-based filaments.
Fibrous spun yarns are sought after for their more natural handle than artificial or synthetic continuous-filament yarns in the preparation of woven or knitted fabrics, the latter being dyed and treated subsequently in order to produce, in most cases, garments.
In order to manufacture a conventional fibrous spun yarn, conventional cotton, or worsted or carded wool type spinning methods are used, or less conventional methods such as open-end spinning. However, these methods employ a large amount of equipment and numerous conversion phases to produce the fibrous spun yarn.
Furthermore, for economic reasons, it is advantageous for the conversion processes to which the yarn is subjected to be integrated as much as possible, and for it to be possible to supply the converter with a yarn which can be used directly.
In order to modify the appearance of continuous-filament yarns, various methods have been used such as crimping, texturing by mechanical or pneumatic means, the production of yarns of special section, matt or semi-matt yarns, etc. . . . The results are not satisfactory, however, for certain applications.
Several patents describe the obtaining of yarns with a modified or fancy appearance from continuous-filament yarns. For example the French patents published under the numbers FR 2,004,868, 2,179,971 and 2,208,406 which describe a core yarn comprising continuous-filament core yarns with fixed false twist and sheath yarns surrounding the core in the form of spirals, the direction of which is reversed along the length of the yarn. However, such yarns have a crepe effect and not the appearance of a spun yarn made from fibers similar to spun yarns of natural fibers. Consequently their handle is harsh and not very fibrous.
U.S. Pat. No. 4,845,934 describes a multifilament yarn containing two types of filaments of different denier, the total count of the yarn being equal to at least 100 times the denier of the thinnest filament which itself is less than 1 dtex. This yarn without twist or interlacing cannot have adequate cohesion for permitting trouble-free workability both when weaving and knitting.
The international patent application published under no. WO 89/4389 likewise describes a core yarn comprising two types of different filaments and having parts where the sheath forms inverted spirals around the core yarns, entangled parts and open parts, the ratio between the length of the open parts and that of the closed parts being at least 0.5. However, this yarn has a cohesion factor (40 to 80 closed parts per meter) which is too small to permit good subsequent workability.
EP no. 349,651 discloses a false-twist core/sheath yarn comprising filaments with different denier and extensibility, having interlaced parts, open parts and intertwined parts, the length of the open parts and of the intertwined parts being in a ratio of 1.5 to 4. However, such a yarn has the disadvantage of using, for the sheath, filaments of a very low denier (&lt;0.6) which are industrially expensive and difficult to produce. Moreover it also has a number of interlacing points (50 to 70 per meter) which is insufficient for permitting good workability and the obtaining of textile articles free from faults.