Classifications

• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01D—MECHANICAL METHODS OR APPARATUS IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS
  • D01D10/00—Physical treatment of artificial filaments or the like during manufacture, i.e. during a continuous production process before the filaments have been collected
  • D01D10/02—Heat treatment
• • D—TEXTILES; PAPER
  • D02—YARNS; MECHANICAL FINISHING OF YARNS OR ROPES; WARPING OR BEAMING
  • D02G—CRIMPING OR CURLING FIBRES, FILAMENTS, THREADS, OR YARNS; YARNS OR THREADS
  • D02G1/00—Producing crimped or curled fibres, filaments, yarns, or threads, giving them latent characteristics
  • D02G1/20—Combinations of two or more of the above-mentioned operations or devices; After-treatments for fixing crimp or curl
  • D02G1/205—After-treatments for fixing crimp or curl

Definitions

• This invention relates to the production of a continuous tow of flat synthetic filaments and to products produced therefrom.
• a process for producing a tow of flat synthetic filaments comprising providing an unset low crimp filament tow, optionally transferring the tow to another site for further processing, and subjecting the tow to heat and tension which substantially removes all of the crimp from the filaments forming the tow.
• the filaments in the final tow can for all intents and purposes be described as 'flat' it should be understood that they may not be strictly planar (as with conventional flat yarn) as they may exhibit a slight surface unevenness. Nevertheless the filaments in the final tow exhibit all of the properties required of flat filamentary yarn in the production of nonwoven fabrics.
• the tow produced in the process of the invention is produced in a conventional manner and is then subjected to a conventional crimping operation by, for example, passing the tow through a stuffer box crimper.
• the process of the invention may be carried out with any of the usual fibrous forming polymeric materials which may be produced in the form of a tow such as polyethylene terephthalate, polyamide, polypropylene and polyacrylics. Furthermore the process can be carried out with tows made from any of the usual bicomponent fibres known in the art to be useful in the production of nonwoven fabrics.
• a process for producing short length synthetic flat fibres comprising providing an unset low crimp filament tow, optionally transferring the tow to another site for further processing, subjecting the tow to a drawing operation which substantially removes the crimp from the filaments forming the tow and cutting the filaments in the tow into the desired short lengths.
• this aspect of the invention may be achieved satisfactorily if the filaments forming the tow are provided with an unset crimp of the order of 2 crimps per crimped centimetre (cpcc) and a crimp ratio of approximately 10%.
• the tow Before cutting the filaments in the tow to the desired short lengths using, for example, a Lummus cutter, it is necessary to remove the crimp from the filaments by subjecting the tow to a suitable drawing operation. Conveniently this is achieved by continuously passing the tow first through a set of rotating feed rolls and then through a set of rotating draw rolls in, for example, a steam chamber, the draw rolls rotating at a slightly higher speed than the feed rolls in order that the tow is drawn.
• the tow was subjected to a drawing operation. This involved taking the unset low crimp filament tow out of the box and feeding it into the feed roll zone of the drawframe.
• the drawframe consisted of 7 rolls in both feed and draw sections with a steam chamber in the draw zone.
• the conditions used were 50 m/min draw speed using a draw ratio of 1.25.
• the latter combined with the steam treatment effectively straightened the tow filaments.
• the tow was then passed through a Lummus cutter and the filaments in the tow were cut into 13 mm length fibre.
• straightened tow could have been wound onto a beam for storage prior to cutting.
• a process for producing a slickened filamentary tow comprising providing an unset low crimp filament tow, applying an emulsion of a slickening agent to the tow, passing the coated tow through an oven at such a temperature and under such tension that (1) the coating is dried and the slickener cured, and (2) the crimp is substantially removed from the filaments forming the tow.
• the unset low crimp filament tow may be packaged and transferred to some other site for further processing.
• the process of the invention may be achieved satisfactorily if the filaments forming the tow are provided with an unset crimp of the order of 8.5 crimps per crimped centimetre (cpcc) and a crimp ratio of approximately 25%.
• the slickening agent used in the process of the invention will be a silicone based polymer such as a polysiloxane.
• a silicone based polymer such as a polysiloxane.
• the slickening agent may be applied to the tow as an emulsion in, for example, water in any suitable manner for example by immersing the tow in a bath containing the emulsion.
• the tow is then passed through an oven in order to dry the tow and cure the slickening agent on to the surface of the filaments in the tow.
• the tow is usually passed through the oven on a brattice. This ensures that no tension is applied to the tow which would otherwise destroy or reduce the crimp of the filaments in the tow.
• the tow is subjected to sufficient tension, while it is passed through the oven, that the unset crimp in the filaments forming the tow is substantially, if not entirely removed.
• this is achieved by passing the tow through two sets of nip rollers one set located upstream of the oven and one set located downstream of the oven, the downstream nip rollers operating at a slightly higher speed, for example 25-30% faster than the upstream nip rollers.
• the crimp disappears on leaving the oven.
• the tow produced in accordance with the invention may be subjected to any further conventional processing steps such as cutting the tow into staple fibres.
• a conventionally made 3.3 dtex/67 Ktex crimped unset nylon 66 continuous filament tow having a cpcc of 8.5 and a crimp ratio of 25% was passed through a dip bath containing a water based siloxane emulsion having a solids content of 2.0%. After passing the tow through a nip roll at 80 psi the emulsion take-up in the tow, prior to being dried and cured, was found to be 27% by weight. The saturated tow was dried and cured in a rotary oven at a temperature of approximately 100°C. A post oven positively driven nip roll operating at a line speed which was approximately 30% greater than the pre-oven nip effectively straightened the tow filaments. The flat slickened tow was subsequently packaged using a conventional tow laying scanner and carton traverse unit.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Textile Engineering (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Yarns And Mechanical Finishing Of Yarns Or Ropes (AREA)
• Preliminary Treatment Of Fibers (AREA)
• Treatments For Attaching Organic Compounds To Fibrous Goods (AREA)

Applications Claiming Priority (4)

Publications (2)

Family

ID=26292796

Family Applications (1)

Country Status (5)

Family Cites Families (3)

• 1988
  • 1988-08-24 EP EP19880307840 patent/EP0310240A3/de not_active Withdrawn
  • 1988-08-24 GB GB888820118A patent/GB8820118D0/en active Pending
  • 1988-09-20 JP JP63236180A patent/JPH0197231A/ja active Pending
  • 1988-09-28 KR KR1019880012526A patent/KR890005309A/ko not_active Withdrawn
  • 1988-09-29 PT PT88621A patent/PT88621A/pt not_active Application Discontinuation

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