Classifications

• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
  • D01F6/00—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof
  • D01F6/78—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from copolycondensation products
  • D01F6/80—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from copolycondensation products from copolyamides

Definitions

• This invention relates to a polyamidic short fiber or staple suitable for staple spinning, and to a method for the preparation thereof.
• polyamidic staples which may be processed with the methods of staple processing, i.e. carding, yarn forming from short fibers, and subsequent textile processing such as weaving, etc., but they have only enjoyed, heretofore, limited applications because of their poor moisture absorption, which results in discomfort for the wearer of the textile articles manufactured from them.
• polyamidic block co-polymer As described and claimed in US Patent No. 4,130,602, which is formed by co-melting a polyamide suitable for melt spinning, such as Nylon 6, with a polydioxyamide, and in particular with poly(4,7-dioxydecamethylene) adipamide.
• Said block co-polymer will be referred to hereinafter as polymer S, for brevity.
• Said block co-polymer exhibits the advantageous property of absorbing significant amounts of moisture, thereby it should afford, when processed into textile articles, a comparable comfort for the wearer to that afforded by articles made of cotton and other natural fibers.
• the method of this invention is useful in the continuous preparation of fibers suitable for staple processing from a block copolymer of Nylon 6 and poly(4,7-dioxydecamethylene) adipamide having the property of absorbing moisture, but being difficult to spin with the prior methods.
• the starting copolymer of Nylon 6 and poly(4,7-dioxydecamethylene) adipamide, containing 10 to 40%, preferably 15 to 30%, and even more preferably 15 to 25%, by weight of the second component, is obtained by co-melting the components as described in the cited US Patent No. 4,130,602.
• the copolymer is then spun, melting the dried chips in extruder such that the temperature of the molten polymer is in the range from 246 to 300° C , preferably in the range from 260 and 280°C, and then extruding the molten polymer through a die the capillaries whereof have a diameter comprised between 0.15 and 0.45 mm.
• the extruded filaments are cooled by blowing, which operation is well known in in the art of polyamide spinning, but the following prescriptions are observed.
• the flow rate of the cooling air should range from 1 00 to 300 m 3 /hour, because higher flow rates would result in filament breakage and lower flow rates than indicated would not cool adequately the bun- die of filaments leaving the die.
• cooling air should be conditioned to a relative humidity in the 50 to 70% range at an approximately ambient temperature, preferably at a temperature in the 10°C to 22°C range.
• the cooled filaments are collected into bins, and optionally conditioned or maintained in a conditioned environment prior to the drawing step, at a temperature of 15 - 30 0 C and relative humidity in the 50% to 70% range.
• conditioning may be effected using the same air which is utilized to cool the filaments as they are extruded.
• Drawing is carried out in air with heat application, preferably in two successive steps
• the first drawing phase takes place at a temperature in the 40°C to 80°C range, and the second step is carried out at a higher temperature of about 110°C to 150°C.
• two sets of draft rollers are provided wherebetween a means, such as a furnace, is interposed which is operative to keep the yarn temperature relatively constant during the second drawing step which takes place within the furnace.
• the temperature of the draft rollers is set at such a level as to heat the yarn progressively from the temperature of the first drawing step (in the 40°C to 80°C range) to the final temperature of the second drawing step varying, as mentioned, from 11 0°c to 15 0°C.
• the overall draft ratio is in the 2.2 to 3.6 range, preferably in the 2. 7 to 3.2 range.
• the drawn filaments are then subjected to a heat setting treatment under tension on hot calenders, such that at least during the final phase of the treatment the temperature is at a level in the 1 80°C to 210°C range; in other words, temperature during this phase should be the highest that the yarn can stand before it starts to melt.
• heat setting would be carried out, of preference, in two stages. During the initial stage, or so-called "preparatory" stage, temperature is raised to a value in the 100°C to 150°C range and the yarn maintained at this temperature for about 4 to 8 seconds.
• the temperature is the highest acceptable for the yarn and is in the 180°C to 210°C range.
• the yarn is maintained at this temperature for about 14 to 28 seconds. It has been found that at lower heat setting temperatures than indicated the desired yarn characteristics cannot be achieved.
• Finishing is then applied at a temperature of about 15 to 55°C.
• Shrinkage is measured in boiling water in conformity with the AST11 2259-77 Method as adapted for the fibers in question.
• the fibers thus obtained are suitable for a staple processing using conventional methods and equipment, a particular example whereof will be described hereinafter.
• the fiber obtained from the polymer S may be successfully utilized both in the production of fibers made of 1 00% copolymer S, and of mixed yarn wi th other synthetic or natural fibers. With the yarn thus produced, both shuttle fabrics (dry goods and shirts) and knitwear may be made.
• the fabrics thus produced have shown to develop clearly valuable characteristics from the standpoint of mechanical strength (wear, tear, etc.), wrinkle- proofness, dimensional stability with maintenance treatments (washing in water and dry cleaning).
• the anti-pilling properties and specially soft and pliable hand (comparable to cashmere) of knitwear are particularly important.
• polymer S comprising 80% Nylon 6 and 20% poly(4,7-dioxydecamethylene) adipamide (also referred to as polymer S 80/20 hereinafter), having a 0.05% residual humidity, are melted at 280°C and extruded through a conventional circular die of steel having 475 holes, size 0.30/0.25 , i.e. a diameter of 0.3 mm and height of 0.25 mm.
• the spinning rate is 700 m/min.
• the filaments are cooled by air blowing at a flow rate Q of 200 m 3 /hour, temperature of 21°C, and relative humidity (U.R.) of 50%.
• Drawing is carried out in two steps , the first at 60°C and the second at 100°C.
• the initial velocity (of the first draft rollers) is 33 m/minute and the velocity of the final draft rollers is 103 m/min, thereby the overall draft ratio is 3.12.
• the drawn fiber is then subjected to heat setting under tension, first at 120 b C for 6 seconds, and then at 195°C for 20 seconds. Thereafter, the fiber is passed through a finishing bath at 52°C, the bath containing 30.0 g/l finish.
• the finish concentration on the fiber shows to be, by analysis, of 0.9 %, the concentration being measured by extraction.
• the fiber is then dried on a hot drum (at 120°C), crimped to impart it with 6 loops/cm, and cut with the short cotton mill method to 40 mm.
• the resulting fiber (fiber S 80/20) has the following characteristics:
• Example I is gone through again, except that the following conditions are used in order to obtain a wool-type staple.
• This Example compares the water retention and water absorption and de-absoprtion characteristics of polymer S fibers according to this invention to prior synthetic fibers and raw cotton.
• Water absorption and de-absorption have been measured as follows.
• the fiber sample whose water absorption properties are to be measured is first thoroughly dried, and then maintained over a time period in a conditioned environment at ambient temperature and controlled relative humidity. Next, the amount of moisture (expressed as percentage by weight) which the fiber takes back is measured by weighing at each assigned value of relative humidity.
• the fiber of polymer S has considerably better absorption, de-absorption, and retention of water characteristics than the synthetic fiber of Nylon 6.
• yarns are produced with a cotton count Ne 24 in 100% fiber S having a denier rating of 1.65 den and 40 mm cut, obtained with the procedure of Example I .
• the fiber S staples, 1 .65 den is processed without any additional antistatic finishing.
• the staples are "opened" on an opener having a single beating reel, at a number of reel beats per minute equal to 40, and at 800 reel rpm.
• a carding operation is effected on a flat card having a staple direct feed system.
• the carded webs are then processed with two passes through a roller drawing frame at the speed of 240 m/min.
• Yarn conversion is carried out on a ring having suitable high pressure swinging arms for synthetic fibers, using the following settings:
• the resulting yarn has the textile characteristics set forth in the following Table.

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• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Artificial Filaments (AREA)
• Yarns And Mechanical Finishing Of Yarns Or Ropes (AREA)
• Spinning Methods And Devices For Manufacturing Artificial Fibers (AREA)

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Citations (4)

• 1982
  • 1982-12-31 IT IT25077/82A patent/IT1157347B/it active
• 1983
  • 1983-12-21 EP EP83112917A patent/EP0115041A3/de not_active Ceased
  • 1983-12-27 JP JP58252268A patent/JPS59173310A/ja active Pending

Patent Citations (4)

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