Classifications

• • D—TEXTILES; PAPER
  • D02—YARNS; MECHANICAL FINISHING OF YARNS OR ROPES; WARPING OR BEAMING
  • D02J—FINISHING OR DRESSING OF FILAMENTS, YARNS, THREADS, CORDS, ROPES OR THE LIKE
  • D02J1/00—Modifying the structure or properties resulting from a particular structure; Modifying, retaining, or restoring the physical form or cross-sectional shape, e.g. by use of dies or squeeze rollers
  • D02J1/22—Stretching or tensioning, shrinking or relaxing, e.g. by use of overfeed and underfeed apparatus, or preventing stretch
  • D02J1/222—Stretching in a gaseous atmosphere or in a fluid bed
• • 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
  • D01F6/58—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from homopolycondensation products
  • D01F6/60—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from homopolycondensation products from polyamides
• • D—TEXTILES; PAPER
  • D02—YARNS; MECHANICAL FINISHING OF YARNS OR ROPES; WARPING OR BEAMING
  • D02J—FINISHING OR DRESSING OF FILAMENTS, YARNS, THREADS, CORDS, ROPES OR THE LIKE
  • D02J1/00—Modifying the structure or properties resulting from a particular structure; Modifying, retaining, or restoring the physical form or cross-sectional shape, e.g. by use of dies or squeeze rollers
  • D02J1/22—Stretching or tensioning, shrinking or relaxing, e.g. by use of overfeed and underfeed apparatus, or preventing stretch
  • D02J1/221—Preliminary treatments

Definitions

• a drawing process for polyamide filaments includes the step of raising the water content of the filaments above the equilibrium value of the filaments with the ambient atmosphere prior to drawing. This is accomplished by passing the filaments through a humid atmosphere at room temperature.
• the present invention relates to improvements in the drawing of synthetic yarn and more particularly to improvernents in drawing, in the solid state, yarn consisting of high molecular weight linear condensation polyamides.
• the yarn which consists of continuous filaments and includes both multifilament yarn and monofilament yarn is thus composed of a high molecular weight synthetic linear condensation polyamide, for example, polyhexamethylene adipamide, but other synthetic linear polyamides may form the material of the filaments, for instance, polyhexamethylene sebacamide, poly-kappa-aminoundecanoic acid, poly-epsilon-caprolactam.
• high molecular weight is meant that the molecular weight of the polyamide is sufliciently high for the latter to be fibreforming.
• Yarn consisting of synthetic linear condensation polyamide filaments for example, a yarn made of polyhexamethylene adipamide, possesses many properties eagerly sought after for textile purposes and, in particular, a highdegree of strength expressed as the tenacity at the point of rupture.
• Such yarn is accordingly manufactured commercially on a large scale, the high tenacity being attained by submitting the filaments to a process of drawing whilst they are in the solid state, a process frequently referred to as cold-drawing.
• the filaments in their undrawn condition after being solution-spun or meltspun from the required polymer, are drawn or elongated in the solid state, commonly by passage between two rolls, the second (or draw roll) revolving at a greater peripheral speed than the first (or feed roll). Between the two rolls the filaments may, if desired, pass round a snubbing pin so as to locate the point at which drawing takes place.
• Another fault apt to occur during drawing is that parts of the yarn fail to become drawn to the desired extent, or even at all, in which case lengths of insufficiently drawn or undrawn yarn are found in the bobbin of yarn taken from the drawing machine.
• short lengths of undrawn yarn sometimes occur in the form of nodules on the drawn monofilament. These nodules are known as nubs.
• the invention consists of a process for drawing in the solid state yarn composed of a high molecular weight synthetic linear condensation polyamide, characterised in that the yarn prior to being drawn is brought into contact with a sufficiently humid atmosphere at room temperature to raise its water content by at least 10% of the value which would be in equilibrium with the water vapour of the ambient atmosphere during, drawing at the same temperature.
• the location of the neck in contact with the snubbing pin during drawing is, in itself, not new because there are other ways, apart from the novel process of the invention, in which the neck can be caused to assume a position on the snubbing pin. This could be achieved, for example, by a reduction in the speed of drawing (though such a course would not be chosen since it would mean a reduced production).
• the invention therefore includes a process for drawing, in the solid state and at a neck, by passage between two rolls, the second revolving peripherally faster than the first, yarn composed of a high molecular weight synthetic linear condensation polyamide, wherein the yarn, on its way from the first roll to the second, is passed round a snubbing pin, and draws at a neck, characterised in that the yarn prior to being drawn is brought into contact with a sufiiciently humid atmosphere at room temperature in order to raise its water content by at least of the Value which would be in equilibrium with the water vapour of the ambient atmosphere during drawing, at the same temperature.
• the neck remains on or very near the snubbing pin.
• the humid atmosphere employed in the present process of drawing to raise the water content of the yarn should possess a relative humidity of at least 85%. Especially good results, moreover, are obtained when the water content of the yarn is raised by at least 100% of the value which would be in equilibrium with the ambient atmosphere.
• the bobbin or cake of undrawn yarn may be enclosed in a suitable box or container lined with bibulous paper or fabric kept saturated with water.
• the box may be conveniently cubical or cylindrical, the material of which it is constructed being, for instance, aluminum or Perspex (registered trade mark).
• the water supply can comprise a wick communicating with a reservoir of the like.
• EXAMPLE 1 A monofilament of polyhexamethylene adipamide having a denier of is drawn using a snubbing pin at a draw ratio of 4.7 at 1500 feet per minute. The temperature is 22 C. and the ambient atmosphere has a relative humidity of 57%. The drawn monofilament has numerous nubs and the neck where drawing occurs is /2 inch from the snubbing pin.
• the cake of undrawn monofilament is placed in a cylindrical box made of Perspex (Registered trade mark) the atmosphere of which has a relative humidity of 67%.
• Perspex Registered trade mark
• the neck where drawing occurs is now in contact with the snubbing pin and the resulting drawn monofilament has very few nubs.
• the relative humidity of the box I is raised to 87% the drawn yarn is completely free of nubs, the neck remaining in contact with the snubbing pin during drawing.
• EXAMPLE 2 Polyhexamethylene adipamide yarn having 6 filaments and a total denier of 40 is drawn with a snubbing pin at a ratio of 4.34 in an atmosphere of 65% relative humidity. By enclosing the undrawn yarn in a box wherein the relative humidity is kept at it is possible to obtain yarn completely free from nubs.
• a yarn drawing process comprising continuously feeding in the solid state melt-spun yarn composed of one or more filaments of a high molecular weight synthetic linear condensation polyamide by feed roll means to draw roll means wherein the draw roll revolves at a greater peripheral speed than the feed roll thus withdrawing the yarn at an increased rate and causing elongation thereof, the improvement consisting in bringing the yarn, prior to being drawn, and while at generally room temperature into contact with a humid atmosphere at room temperature and having a relative humidity of at least 85 whereby the water content of the yarn is raised by at least 10% of the value which is in equilibrium with the water vapour of the ambient drawing atmosphere at the same temperature.
• a yarn drawing process comprising continuously feeding in the solid state melt-spun yarn composed of one or more filaments of a high molecular weight synthetic linear condensation polyamide by feed roll means to draw roll means wherein the draw roll revolves at a greater peripheral speed than the feed roll thus withdrawing the yarn at an increased rate and causing elongation thereof, snubbing the movement of said yarn by passing it round a snubbing pin situated between the feed roll means and the draw roll means so that there is a tendency for the point of necking down of the filaments to be localised, the improvement consisting in bringing the yarn prior to being drawn and while at generally room temperature into contact with a humid atmosphere at room temperature and having a relative humidity of at least 85% whereby the water content of the yarn is raised by at least 10% of the value which is in equilibrium with the water vapour of the ambient atmosphere at the same temperature.

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• Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Yarns And Mechanical Finishing Of Yarns Or Ropes (AREA)
• Woven Fabrics (AREA)
• Artificial Filaments (AREA)

Applications Claiming Priority (1)

Publications (1)

Family

ID=10453823

Family Applications (1)

Country Status (6)

Cited By (1)

Citations (16)

• 1963
  • 1963-12-17 GB GB49867/63A patent/GB1004657A/en not_active Expired
• 1964
  • 1964-12-04 US US416126A patent/US3514460A/en not_active Expired - Lifetime
  • 1964-12-11 DE DE19641435372 patent/DE1435372A1/de active Pending
  • 1964-12-14 NL NL6414520A patent/NL6414520A/xx unknown
  • 1964-12-16 LU LU47591A patent/LU47591A1/xx unknown
  • 1964-12-17 BE BE657282A patent/BE657282A/xx unknown

Patent Citations (16)

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