Textiles: manufacturing – Thread finishing – Surface modification of running length
Patent
1997-11-26
2000-02-15
Vanatta, Amy B.
Textiles: manufacturing
Thread finishing
Surface modification of running length
28246, 2642905, 2642896, D02J 122
Patent
active
060238240
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The invention relates to a process for producing high strength, high shrinkage nylon 66 filament yarn for industrial fabrics, especially airbag fabrics, by multistage drawing of polyamide 66 LOY by means of at least three heatable draw roll units or godet duos and direct winding up of the drawn yarn to form a cylindrical yarn package, specifically a cheese, and to nylon 66 filament yarn.
High shrinkage thermoplastic filaments are typically wound onto cops with a protective twist suitable for the further processing. The disadvantage of winding onto cops is that the maximum winding speeds are only of the order of a few hundred metres per minute. A further disadvantage of winding onto cops is that the yarn capacity of a drawn cop is generally limited to about 4 kg of yarn. Economical yarn manufacture is no longer guaranteed after such a process. It would be desirable to wind high shrinkage yarns directly onto cylindrical bobbins. However, it has hitherto not been possible to wind thermoplastic polymer yarns possessing high hot air shrinkage. Such yarn has to be wound up under relatively high tension in order that an undesirable reduction in the hot air shrinkage may be prevented. This has serious disadvantages for the package build. The high yarn tension creates such high radial forces within the cross-wound package that, on the one hand, the package centres are deformed, so that the full package cannot be removed from the mandrel of the winding machine. A further disadvantage is, on the other hand, that unacceptable winding deformations are observed, which make it impossible to build full packages.
DE-A-34 37 943 discloses a process for producing nylon 66 filament yarn wherein an undrawn yarn of polyhexamethyleneadipamide having a relative viscosity of 60 to 100 in formic acid is drawn in one or two stages. The apparatus suitable for this purpose consists of a plurality of heated draw roll units. To improve the drawability of the yarn additional heat sources in the form of contact heaters are provided between the draw rolls. It is known that, in the melt-spinning process, at a winding speed of 4500 m/min and higher, the winding tension is so high that it is no longer possible to remove a paper centre from the winding machine. The problem is solved in this process by relaxing by about 10%. Nothing is said about the winding of the drawn yarn. The known yarns are wound up at speeds of not more than 20 m/min. The aim of the known process is the production of dimensionally stable filament yarns for tyre cord fabrics, possessing high strength, high elongation and low shrinkage, ideally below 5%. The drawing conditions and especially the winding conditions onto cheeses are optimized for these yarns.
Lately, however, airbag fabrics specifically are increasingly produced using yarns having high hot air shrinkage. It is true that such yarn types are easy to produce, but they are difficult to wind onto cheeses.
SUMMARY OF THE INVENTION
It is an object of the invention to provide a process for the direct winding of high strength synthetic yarns directly onto cheeses following the hot drawing process.
It is a further object to produce high strength nylon 66 filament yarn having high shrinkage and make it available on a cheese.
It is a further object to improve not only the production speed but also the unit weight of the yarn packages and thus the economics of the drawing and winding process. Equipment for producing cylindrical packages permit production speeds of several thousand metres per minute.
The object is achieved according to the invention when, at a relaxation ratio of 4 to 10%, the temperature of the last draw roll unit before winding is set to between 70.degree. C. and 160.degree. C., especially 80.degree. C. and 150.degree. C., preferably to 90.degree. C.-140.degree. C., and the winding tension to less than 0.2 cN/tex, especially to less than 0.15 cN/tex, preferably less than 0.13 cN/tex.
Yarn tension in winding is essentially determined by the relaxation ratio, i.e. by the ra
REFERENCES:
patent: 2807863 (1957-10-01), Schenker et al.
patent: 3716611 (1973-02-01), Chapman
patent: 4042662 (1977-08-01), Corbin, Jr. et al.
patent: 4338277 (1982-07-01), Saito et al.
patent: 4648240 (1987-03-01), Hallsworth et al.
patent: 5139729 (1992-08-01), Clark, III et al.
patent: 5223197 (1993-06-01), Boles et al.
patent: 5240667 (1993-08-01), Andrews, Jr. et al.
Berger Luzius
Fischer Klaus
Linz Hans
Rhodia Filtec AG
Striker Michael J.
Vanatta Amy B.
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