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
  • D02J1/225—Mechanical characteristics of stretching apparatus
• • 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
  • D01F6/62—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from homopolycondensation products from polyesters

Definitions

• This invention relates to a process for the manufacture of polyester synthetic fiber, and more particularly to a synthetic fiber composed of terephthalate polyester which has an improved dyeability.
• a polyester synthetic fiber In order to improve its mechanical properties, a polyester synthetic fiber is generally heated to a temperature above its second order transition temperature, drawn 3.5- 5.5 X, and thereafter heat-treated. As a result, the degree of orientation and crystallinity of the fiber becomes high, and its interior structure is so compact as to make it difficult for the dyestuff molecules to enter. Consequently, the dyeability is worsened.
• such remedies as the copolymerization of a third component with the polyester synthetic polymer or the heat-treatment of the fiber at high temperature in chemicals.
• the thermal resistance of the fiber is lowered, and the latter treatment involves a defect of high cost, and marked degradation of the fiber.
• a portion of the acid component accounting for up to 15 mol percent may be bibasic acids other than terephthalic acid such as isophthalic acid, parahydroxy benzoic acid, vanillic acid and adipic acid.
• the terephthalate polyester may contain, as a branching agent, benzene 1,3,5-tricarboxylic acid 5 oxydimethyl isophthalate in substitution of part of the bibasic acid component, and a polyhydric alcohol such as pentaerithritol, glycerine nad sorbitol in place of part of the dihydric alcohol.
• branching agent can usually be used in the amount up to about 1.0 mol percent of the acid or alcohol component.
• the starting undrawn filament of this invention should have a birefringence of at least 0.0050, and preferably at least 0.0080, which is higher than those of ordinary undrawn filaments.
• a birefringence of at least 0.0050, and preferably at least 0.0080, which is higher than those of ordinary undrawn filaments.
• an undrawn filament having a birefringence lower than 0.0050 is subjected to the drawing and heat-treating operations of this invention, a desired improvement in dyeability cannot be achieved. It is also difficult to manufacture a product having excellent dyeability from an undrawn filament having excess birefringence (more than 0.0250).
• the birefringence of the starting undrawn filament of the process of this invention should be in the range of 00050-00250, and preferably in the range of 00080-0020.
• the birefringence of the undrawn filament depends upon spinning conditions in the manufacture of undrawn filaments, particularly upon the spinning speed, cooling rate of the thread line, the spinneret temperature and the types of the polymers (especially, degree of branching and polymerization). Among these conditions, the spinning speed and the cooling rate are particularly dominant. Generally speaking, a high spinning speed and cooling rate result in a higher birefringence.
• the birefringence of the undrawn filament prepared by the steps of melting polyethylene terephthalate chip having an intrinsic viscosity of 0-60 and extruding the molten polyethylene terephthalate from a spinneret having 0.35 mm.
• x 50 holes into the air at room temperature at a spinneret temperature of 275 C. varies among 0.0096, 0.0148 and 0.0215 depending upon 1500 mm./min., 2000 m./min. and 2500 m/min, respectively Also, the birefringence of an undrawn filament obtained by extruding a polyethylene terephthalate adipate copolymer chip (3 mol percent adipate) having an intrinsic viscosity of 0.64 from a spinneret having 0.24 mm.
• the undrawn filament having a relatively high birefringence as specified above is drawn at a temperature of 40-95 C. at a draw ratio ranging from its minimum draw ratio to a ratio slightly higher than this.
• the minimum draw ratio means a minimum of the draw ratios at which no filaments remain substantially undrawn.
• its minimum draw ratio is decided according to the following procedures. Namely, a given tow of an undrawn filament is drawn and taken up at a rate of 100 m./min., and maintained at 145 C. for 15 minutes while allowing a free shrinkage. This is thereafter cut into staple fibers of 3 cm. length. The staple fibers are then dyed for 5 minutes at a bath ratio of 1:100 in a dispersion containing 4% O.W.F. of Dispersol Fast Scarlet B-150F (CI. 11110) and 0.5 g./litre of sodium dodecylsulfate.
• the dyed staple fibers are dried and observed under a magnifying glass to count the number of the fibers (undrawn filaments) dyed especially in deep color. When this number exceeds 200 among 100,000 filaments, the draw ratio used is regarded as being lower than the minimum draw ratio.
• an undrawn filament of polyethylene terephthalate having a birefringence of 0.0081 is tested in a water bath of 80 C. using various draw ratios, the following results are obtained.
• the minimum draw ratio of the said undrawn filaments determined in a water bath of 80 is 1.90.
• the minimum draw ratio depends upon the birefringence of the given undrawn filaments and the types of the polymers, particularly upon its degree of branching. Generally speaking, the higher the birefringence is and the higher the degree of the branching of the polymer is, the lower the minimum draw ratio becomes.
• the determination of the minimum draw ratio is hardly affected by the dyeing conditions in the above tests.
• a simplified method of determining the minimum draw ratio is to examine a sample of tow which is drawn and heated for minutes at 145 C. while allowing a free shrinkage. When the sample is not substantially stuck together, the empoyed draw ratio can be regarded as not being lower than the minimum draw ratio.
• the draw ratio to be used in the process of this invention should be in the range from the minimum draw ratio to a ratio slightly higher than this. At a draw ratio lower than the minimum draw ratio, the obtained product contains an undrawn portion. When the draw ratio is excessive, a desired effect of the improvement of the dyeability cannot be achieved. We have found that it is possible to use a draw ratio higher than the minimum draw ratio by about 0.5 and preferably by 0.3.
• the draw temperature may be in the range of 40-95 C. In general, when the temperature is too low, drawing cannot be effected smoothly, and when the temperature is too high, a desired effect of the improvement of dyeability cannot be achieved.
• the preferable range of the draw temperature is 60-70 C.
• the drawing as above mentioned can be effected either by using a gaseous or liquid medium, or by contact heating by means of a hot plate.
• the draw rate is not an important requirement and can be selected Within the range of 10-500 m./min., and particularly 150 m./min.
• the drawn filament, so obtained, is heated, under a shrinkable state at a temperature of 100-220 C., and preferably 130-180 C.
• a temperature of 100-220 C., and preferably 130-180 C When the temperature is too low, the shrinkage and setting are not fully achieved and when it is too high, the fibers are stuck together. This is not desirable.
• the heat treatment is carried out under a state of a free or limited shrinkage. In this treatment, the fibers are subjected to about 560% of shrinkage.
• the heat treatment may be effected by using either gas or liquid medium, or by contact heating,
• the polyester fiber to be manufactured by the process of this invention may be cut into staple fibers prior to, or after, the said heat treatment. Furthermore, it is possible to subject the tow drawn and heated in accordance with the process of this invention to an additional drawing. We have found that this additional drawing gives rise to the improvement of the strength and elongation of the obtained product, and does not give substantial damage to the excellent dyeability once obtained. This is extremely surprising.
• the polyethylene terephthalate fiber obtained in accordance with the process of this invention can be dyed in deep colours without the reliance of a special dyeing technique.
• the obtained dyeings exhibit more excellent fastness to washing as compared with the ordinary polyethylene terephthalate dyed in the same degree of deep colour by means of a special dyeing method such as high temperature dyeing or carrier dyeing. This is an unexpected fact.
• the polyethylene terephthalate fiber whose dyeability is improved by heat treatment under shrinkage at high temperature as more than 220 C. has a poor elastic recovery.
• the product in accordance with the process of this invention is as superior as the ordinary polyethylene terephthalate fiber with respect to its elastic recovery.
• the polyethylene terephthalate fiber obtained in accordance with the process of this invention has a very low creep strain (strain which results by application of a specific load for a prolonged time) and a low residual strain after creep recovery (residual strain when the said load is taken off to recover the creep).
• the said creep strain and residual strain after creep recovery are the minimum for the fibers of this invention and the maximum for the isophthalate modified fiber. The difference between these becomes increasingly remarkable as the temperature at determination becomes higher from room temperature, 50 C. to C. This shows that the fiber obtained in accordance with the process of this invention has a very excellent dimensional stability against the changes in stress, temperature and time.
• the fabrics woven from the staple fibers obtained in accordance with the process of this invention have improved resistance to pilling.
• the dye absorptions are the values determined with respect to Dispersol Fast Scarlet B-ISOF (C.I., 11110) in accordance with JIS (Japanese Industrial Standard).
• the sample is dyed at a bath ratio of 1:100 in a dispersion containing 4% O.W.F. of the dyestuff and 0.5 g./litre sodium dodecylsulfate for minutes at C.
• the degree of light absorption (wave length 500 me) is determined by means of a photocolouring meter, and expressed in terms of ratio to the value prior to the dyeing.
• EXAMPLE 1 An undrawn filament of polyethylene terephthalate having a birefringence of 0.0081 was drawn in a hot water bath of 65 and 80 C. at a ratio of 2.0x and 3.6x, and taken up at a speed of 100 m./min. It was thereafter heated at 145 C. for 15 minutes under a state of free shrinkage. The obtained fibers had the properties shown below.
• EXAMPLE 2 An undrawn filament of polyethylene terephthalate having a birefringence of 0.1860 was drawn 1.5x on a hot pin having a surface temperature of 70 C. and
• Polyethylene terephthalate isophthalate chip containing 9 mol percent of isophthalic acid as acid component (having an intrinsic viscosity of 0.67 and a softening point of 241 C.) was extruded from a spinneret of 255 C. into of 1700 m./min. There was obtained a 5 denier per filament undrawn yarn having a birefringence of 0.0123. This yarn was drawn 1.95 on a hot pin of 55 C. and wound up at a rate of 45 m./min. It was then shrunk 20% on a metal plate of 130 C. and successively drawn passed successively on a metal plate of 180 C. at a rate 5 o of m./min.
• the resulting fiber had a dye Draw pewent percent percent absorption of 58%, a tenacity of 4.35 g./d. and an elon- 1.9 89 gation of 56.5%.
• Example 5 The same chrp as used in Example 8 was spun at a EX r rate of 2,500 m./min. Using the same quenching chimney The same procedures as in Example 4 were repeated as in Example 4, the filaments are quenched by air which except that there were used polyethylene terephthalate was blown at a linear speed of m./min. There was chips having an intrinsic viscosity of 0.55, a take-up rate btained a 6.0 denier per filament undrawn yam having of 2,200 m./min. and the air of 10 C. There was oba birefring nce of 0.0289. This yarn was drawn 1.l0 tained undrawn filament having a birefringence of 0.0239.
• Example 4 The properties of the thus 60 E 10 obtained yarns in comparison with the shrunken yarn not The fiber of Example 4 obtained by drawing 2.2x and treated further are shown in the following table.
• the fiber obtained in Example 8 were dyed for 90 minutes Rex-drawing Dye Elon- Shrinkage in temperature, Re-draw absorption, Tenacity, gation, bollmg water, (O.) ratio percent g./d. percent percent 88. 3 2. 75 49. 5 0. s 200 1. 3 86.3 a 21 30. 4 2.1 230 1. 3 s7. 1 3. 27 33.6 1. 8
• Process for the manufacture of polyester synthetic fibers having improved dyeability and yarn characteristics which comprises the steps of (1) drawing and undrawn yarn composed of terephthalate polyester and having a birefringence of 00050-00250, at a temperature of 55-95" C. to about 15-22 times its original length and at a draw ratio ranging from the minimum draw ratio of said undrawn yarn to a draw ratio about 0.5 higher than this; (2) heat-treating the said yarn under a shrinkage of about -60% at a temperature of 100220 C.; and (3) thereafter re-drawing said heattreated yarn at a temperature of not less than about 160 C. to not less than about 1.16 times the length of said heat-treated yarn.

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

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Citations (11)

• 0
  • GB GB1050393D patent/GB1050393A/en active Active
• 1965
  • 1965-01-22 US US427471A patent/US3527862A/en not_active Expired - Lifetime
  • 1965-02-02 DE DE19651494754 patent/DE1494754A1/de active Pending
  • 1965-02-04 NL NL656501418A patent/NL141936B/xx unknown
  • 1965-02-05 FR FR4603A patent/FR1423581A/fr not_active Expired

Patent Citations (11)

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