JP2006257560A - Polyester core-sheath conjugate fiber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a high-strength polyester core-sheath conjugate fiber having excellent color development and softness and high strength of fabric. <P>SOLUTION: The polyester core-sheath conjugate fiber is a conjugate fiber in which a polyethylene terephthalate composed of terephthalic acid as an acid component and ethylene glycol as a glycol component is arranged in a core part and a polytrimethylene terephthalate composed of terephthalic acid as an acid component and trimethylene glycol as a glycol component is arranged in a sheath part and which has a concentric core-sheath crosssectional shape in the length direction. The intrinsic viscosity of the polytrimethylene terephthalate arranged in the sheath part is high comparing with that of a polyethylene terephthalate arranged in the core part and the difference between both the intrinsic viscosities is 0.4-1.0. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a polyester composite fiber having a core-sheath cross-sectional structure, and relates to a polyester core-sheath composite fiber excellent in color development property, fabric softness, and high strength.

Polytrimethylene terephthalate (hereinafter referred to as 3GT) obtained by polycondensation of lower alkyl ester of terephthalic acid typified by terephthalic acid or dimethyl terephthalate and trimethylene terephthalate is low elastic modulus, soft texture, easy Features such as dyeability have attracted attention, and in recent years, their demand has greatly expanded. However, the 3GT single yarn only yields a fabric with low strength, and there is a drawback that during weaving and knitting, the yarn is easily cut when tension is applied to the yarn. In addition, it is generally known that a high draw ratio may be used to obtain a high-strength yarn. However, at a high draw ratio, the elongation decreases and the color developability deteriorates. Thus, with 3GT alone, a color developing property, softness good and high strength could not be obtained. Therefore, in order to compensate for the shortcomings of the single polytrimethylene terephthalate yarn, development of a core-sheath type composite fiber of polyethylene terephthalate (hereinafter referred to as PET) and 3GT has been promoted and is known as a known technique. For example, the reinforcement of strength and elastic modulus by disposing PET in the core and 3GT in the sheath is disclosed (see Patent Document 1). However, in this case, the elasticity becomes PET-like as well as the reinforcement of strength, so that the color developability and soft feeling are equivalent to PET, and the strength (toughness) is reduced while achieving both the color developability and softness peculiar to 3GT. It was not possible to increase to a good region for processing. Furthermore, it discloses that PET having a high concentration of metal oxide added to the core is used to obtain a fiber with good light shielding properties (see Patent Document 2). However, this also halves the characteristics of 3GT and the color developability becomes insufficient. Further, when the difference in intrinsic viscosity between PET and 3GT is small as in the known art, there is a drawback that the softness of the fabric is easily lost.
JP-A-11-93021 (Claims) JP-A-11-81048 (Claims)

  The present invention provides a high-strength polyester core-sheath composite fiber that is excellent in color developability and softness of a fabric.

The present invention has arrived at the present invention as a result of intensive studies in order to solve the problems that cannot be solved by the above-described prior art. That is, the present invention
(1) Polyester A having terephthalic acid as an acid component and trimethylene glycol as a glycol component is arranged in the core, polyester B having terephthalic acid as an acid component and ethylene glycol as a glycol component is arranged in the sheath, It is a composite fiber having a concentric core-sheath cross-sectional shape in the longitudinal direction, and the intrinsic viscosity of polytrimethylene terephthalate disposed in the sheath is higher than that of polyethylene terephthalate disposed in the core, and the difference is 0. It is a polyester core-sheath composite fiber characterized by being 4-1.0. Also,
(2) The polyester core-sheath conjugate fiber according to (1), wherein the initial tensile resistance is 20 to 40 cN / dtex and the high elongation product is 5.0 to 6.0 cN / dtex.

  According to the present invention, it is possible to provide a polyester core-sheath composite fiber having excellent color developability, fabric softness, and high strength, which could not be achieved conventionally.

  The polyester core-sheath composite fiber of the present invention has a concentric core-sheath cross-sectional shape, and the PET disposed in the core part is polyethylene terephthalate in which 90 mol% or more is composed of repeating units of ethylene terephthalate. Polyethylene terephthalate is a polyester obtained using terephthalic acid as the main acid component and ethylene glycol as the main glycol component. However, it may contain a copolymer component capable of forming another ester bond at a ratio of 10 mol% or less. Examples of copolymerizable compounds include dicarboxylic acids such as isophthalic acid, cyclohexanedicarboxylic acid, adipic acid, dimer acid, and sebacic acid, while glycol components include, for example, ethylene glycol, diethylene glycol, butanediol, neopentyl glycol, and cyclohexanedimethanol. , Polyethylene glycol, polypropylene glycol and the like can be mentioned, but are not limited thereto. Further, titanium dioxide as a matting agent, silica or alumina fine particles as a lubricant, hindered phenol derivatives, coloring pigments and the like as antioxidants can be added as necessary.

  Moreover, 3GT distribute | arranged to a sheath part is a poly trimethylene terephthalate which 90 mol% or more consists of a repeating unit of a trimethylene terephthalate. Polytrimethylene terephthalate is a polyester obtained using terephthalic acid as the main acid component and trimethylene glycol as the main glycol component. However, it may contain a copolymer component capable of forming another ester bond at a ratio of 10 mol% or less. Examples of copolymerizable compounds include dicarboxylic acids such as isophthalic acid, cyclohexanedicarboxylic acid, adipic acid, dimer acid, and sebacic acid, while glycol components include, for example, ethylene glycol, diethylene glycol, butanediol, neopentyl glycol, and cyclohexanedimethanol. , Polyethylene glycol, polypropylene glycol and the like can be mentioned, but are not limited thereto. Further, titanium dioxide as a matting agent, silica or alumina fine particles as a lubricant, hindered phenol derivatives, coloring pigments and the like as antioxidants can be added as necessary.

  The intrinsic viscosity of 3GT arranged in the sheath part is made higher than the intrinsic viscosity of PET arranged in the core part, and the intrinsic viscosity difference needs to be 0.4 to 1.0. When the intrinsic viscosity difference is less than the specified range, when the viscosity of PET is increased, it is generally necessary to set the spinning temperature to be higher in accordance with the viscosity. Further, it is not preferable because low-strength yarns and, further, color developability and softness are deteriorated due to 3GT thermal deterioration. Further, when the viscosity of 3GT is lowered, 3GT characteristics such as color developability and softness are not exhibited. The range of the intrinsic viscosity difference is preferably 0.5 or more. On the other hand, if the intrinsic viscosity difference is not less than the specified range, it is not preferable if the PET viscosity is lowered and the strength reinforcing effect of the PET is lost, resulting in a low-strength yarn. This is not preferable because it becomes difficult. The range of the intrinsic viscosity difference is preferably 0.8 or less.

  The initial tensile resistance is preferably 20 to 40 cN / dtex. It is preferable that the initial tensile resistance is 20 cN / dtex or more because strength reinforcement by PET becomes more effective. More preferably, it is 25 cN / dtex or more. Further, it is preferable that the initial tensile resistance is 40 cN / dtex or less because color development and softness peculiar to 3GT are more exhibited. More preferably, it is 38 cN / dtex or less.

The high elongation product is preferably 5.0 to 6.0 cN / dtex. It is preferable that the strength elongation product is 5.0 cN / dtex or more because strength reinforcement by PET becomes more effective. More preferably, it is 5.1 cN / dtex or more. Further, it is preferable that the high elongation product is 6.0 cN / dtex or less because color development and softness peculiar to 3GT are more exhibited. More preferably, it is 5.8 cN / dtex or less. In the polyester core-sheath composite fiber of the present invention, the weight ratio of the core part to the sheath part is 20:80 to 55 in order not to impair the color development and softness characteristic of 3GT. : 45, the intrinsic viscosity of PET is 0.40 to 0.68, and the intrinsic viscosity of 3GT is 0.80 to 1.68. Moreover, in the shrinkage | contraction characteristic of the polyester core sheath composite fiber of this invention, it is 7 to 20% in boiling water shrinkage, 10 to 20% in 160 degreeC dry heat shrinkage, and 0.1 to 0.4 cN in heat shrinkage stress peak value. A range of / dtex is appropriate.

  The polyester core-sheath conjugate fiber of the present invention is produced by any known method, but the melt spinning method is the most excellent in view of the stability and productivity of the composite structure. When the composite fiber is melt-spun, it is preferable that the PET serving as the core is melted at 260 to 300 ° C. In the melting, a pressure melter method and an extruder method can be mentioned, and melting by an extruder is preferable from the viewpoint of uniform melting and prevention of stagnation.

  Moreover, 3GT used as a sheath part is preferably melted at 240 to 280 ° C. using an extruder similarly to PET. Separately melted polymers pass through separate pipes, weigh and then flow into the base pack. Under the present circumstances, it is preferable that piping passage time is 5 to 30 minutes from a viewpoint of suppressing thermal deterioration. The polymer that has flowed into the pack is merged by the die, is combined into a concentric core-sheath shape by a known technique, and is discharged from the die. The polymer temperature at this time is suitably 263 to 280 ° C. If it is this range, the fall of productivity and the coloring property by a heat degradation and the fall of a soft feeling can be prevented.

  The polymer discharged from the die is cooled and solidified, and after the oil is applied, it is taken out. The take-up speed is possible at any speed of 500 to 6000 m / min. In a method in which an undrawn yarn called a two-step method is once wound and then drawn, the take-up speed is 500 to 2000 m / min. Further, the film may be taken up in a region up to 4000 m / min, and the partially oriented yarn may be wound once and then drawn. In order to obtain uniform physical properties, it is preferable to obtain a partially oriented yarn by conducting a heat treatment before winding to promote crystallization by heat and then winding. On the other hand, in the one-step method, there is a method of obtaining drawn yarn at a speed at a speed of 4000 to 6000 m / min. Also in this case, it is effective to perform heat treatment before winding. Furthermore, a method called a direct spinning drawing method is also included. This method is a method of taking up in an undrawn yarn or partially oriented yarn region of 500 to 4000 m / min and winding it after preheating, drawing, and heat treatment to obtain a drawn yarn without winding up once. In the spinning and drawing methods mentioned above, the draw ratio is suitably set so that the drawn yarn elongation becomes a target value. Further, in any of the spinning and drawing processes, it is possible to perform entanglement using a known entanglement device up to winding. If necessary, it is possible to increase the number of confounding by giving multiple times. Furthermore, it is also possible to add an additional oil immediately before winding.

Hereinafter, although an example is given and explained concretely, the present invention is not limited to an example. In addition, the main measured value of the Example was measured with the following method.
(1) Intrinsic viscosity Intrinsic viscosity [η] is a value determined based on the following defining formula.

Ηr in the definition formula is a value obtained by dividing the viscosity at 25 ° C. of a diluted solution of 3GT dissolved in O-chlorophenol having a purity of 98% or more by the viscosity of the solvent itself measured at the same temperature. Is defined. C is the solute weight value in grams in 100 ml of the solution.
(2) Melt Viscosity Using Capillograph 1B manufactured by Toyo Seiki Co., Ltd., measurement was performed three times at a temperature of 280 ° C. and a shear rate of 6080 (1 / sec) in a nitrogen atmosphere, and the average value was taken as the melt viscosity.
(3) Initial tensile resistance, strength, elongation Measured according to JIS L1013 (1999).
(4) Strong elongation product Strong elongation product (cN / dtex) = strength (cN / dtex) × (1+ (elongation (%) / 100))
(5) Boiling water shrinkage Boiling water shrinkage (%) = ((L0−L1) / L0) × 100
L0: skein of raw yarn, skein length at a measurement load of 0.029 cN / dtex L1: treatment of raw yarn with no load in boiling water at 100 ° C. for 15 minutes, air drying, measurement load of 0.029 cN Skein length when / dtex is applied (6) Color developability Sample of polyester core-sheath composite fiber (sample A) of the present invention and PET single yarn (sample B) is knitted in a cylinder, and tetraseal navy blue SGL0.275 as a dye. % Owf, Tetrocin PE-C 5.0% owf as an auxiliary agent, Nikkasan Salt # 12001.0% owf as a dispersing agent, dyed at 50 ° C. for 15 minutes at a bath ratio of 1: 100, and further at 90 ° C. for 20 minutes. Went. The dyeing difference between samples A and B after dyeing was comprehensively subjected to a sensory test and evaluated in three stages. In addition, ○ or more was regarded as passing. The PET single yarn was 84 dtex-48f filament (filament (hereinafter abbreviated as f)).

○○: Very good ○: Excellent ×: PET equivalent (no color development improvement)
(7) Softness The polyester core-sheath composite fiber of the present invention was made into a fabric and touched by 10 panelists to evaluate whether the softness was good. The evaluation criteria were as follows. In addition, ○ or more was regarded as passing. As the fabric, the polyester core-sheath composite fiber (84 dtex-48f) of the present invention is used as the weft, and the PET single yarn (33 dtex-12f) is used as the warp. The weft density is 95 / inch and the warp density is 138 / inch. did.
◯: Very good ◯: Good x: PET equivalent (8) Evaluation of fabric fluff The fabric described in (6) was inspected, and the number of fabrics with 100 fluffs was evaluated according to the following evaluation criteria as a three-step evaluation. In addition, ○ or more was regarded as passing.
○○: 0 to 3 mm ○: 4 to 6 mm ×: 7 mm or more Example 1
PET with intrinsic viscosity of 0.51 and 3GT with intrinsic viscosity of 1.13 were melted at 285 ° C and 260 ° C, respectively, using an extruder and weighed with a pump. Was poured into a known base. The composite ratio was a ratio of PET: 3GT = 30: 70. Pipe passage time of each polymer was 12 minutes for PET and 5 minutes for 3GT. The yarn discharged from the die is cooled and applied with an oil agent, and then taken up by a first hot roller heated to 55 ° C. at a speed of 1600 m / min, and is temporarily wound up to 155 ° C. at a speed of 4050 m / min. The film was drawn around a heated second hot roller, and stretched and heat set. Further, two godet rollers were drawn around at 4000 m / min and then wound up at 3970 m / min to obtain an 84 dtex-48f polyester core-sheath composite yarn. The tension at the winder inlet was 0.15 cN / dtex. The results of physical properties and texture evaluation are as shown in Table 1. The color development and softness were excellent, and the fabric fluff evaluation was also good.

Example 2
Except that the composite ratio was PET: 3GT = 50: 50, yarn was produced under the same conditions as in Example 1 to obtain a 84 dtex-48f polyester core-sheath composite yarn. The results of physical properties and texture evaluation are shown in Table 1. Although slightly inferior to Example 1, the color development and softness were excellent, and the fluff evaluation of the fabric was also good.

Example 3
A polyester core-sheath composite yarn of 84 dtex-48f was produced under the same conditions as in Example 1 except that PET having an intrinsic viscosity of 0.62 was used, the intrinsic viscosity difference was 0.51, and the polymer temperature was 275 ° C. Got. The results of physical properties and texture evaluation are as shown in Table 1. Although slightly inferior to Example 1, the color development and softness were excellent, and the fluff evaluation of the fabric was also good.

Comparative Example 1
A polyester core-sheath composite yarn of 84 dtex-48f was produced under the same conditions as in Example 2 except that PET having an intrinsic viscosity of 0.62 and 3GT having an intrinsic viscosity of 0.75 were used and the polymer temperature was 275 ° C. Obtained. The results of physical properties and texture evaluation are as shown in Table 1. Although the fluff evaluation of the fabric was good, none of the soft feeling, dyeing uniformity, and color development were satisfactory.

Comparative Example 2
A 3GT single yarn of 84 dtex-48f was obtained by spinning under the same conditions as in Example 1 except that 3GT having an intrinsic viscosity of 1.13 was spun alone. The results of physical properties and texture evaluation are shown in Table 1. The initial tensile resistance was low, the softness was excellent, and the color development was also excellent, but the strength was low and not satisfactory. Also in evaluation, it was inferior to the core-sheath type.

  Since the polyester core-sheath conjugate fiber obtained in the present invention has high strength, it is suitable not only for clothing but also for industrial use, and has a uniform surface feeling that produces a unique soft feeling, color development, and uniform dyeability. Is obtained.

  Applications that can be applied are not limited to this, and can be woven or knitted with natural fibers such as cotton. In addition to various woven and knitted fabrics, it can also be applied to material applications. Further, the present invention can be applied not only to a fine filament multifilament but also to a thick filament cocoon filament and a monofilament, but the application range is not limited thereto.

Claims (2)

  Longitudinal direction, polyethylene terephthalate containing terephthalic acid as acid component and ethylene glycol as glycol component is arranged in the core, polytrimethylene terephthalate containing terephthalic acid as acid component and trimethylene glycol as glycol component is arranged in the sheath Is a composite fiber having a concentric core-sheath cross-sectional shape, and the intrinsic viscosity of polytrimethylene terephthalate disposed in the sheath is higher than the intrinsic viscosity of polyethylene terephthalate disposed in the core, and the difference is 0.4 to A polyester core-sheath composite fiber characterized by being 1.0.   The polyester core-sheath conjugate fiber according to claim 1, wherein the initial tensile resistance is 20 to 40 cN / dtex and the high elongation product is 5.0 to 6.0 cN / dtex.