JP3953052B2 - Composite fiber and method for producing the same - Google Patents

Description

  The present invention relates to a composite fiber having improved stretchability, improved heat setability and improved product stability when applied to post-processing, and a method for producing the same. More specifically, the crimp elongation rate is 50% or more. In addition, while having high elasticity with an elastic recovery rate of 70% or more, the heat setability after no-load boiling water treatment is 80% or more, and the elastic modulus and elongation change rate when stretched 10% before and after heat setting is 20 The present invention relates to a composite fiber that is excellent in product stability when applied to post-processing of a product and a method for producing the same.

  In addition, the present invention uses a method of joining under a spinneret to produce a side-by-side mold having a curvature index of 1.2 or less and a degree of deformity of 1.3 to 2.5. Compared to the eccentric core-sheath type yarns, the side-by-side cross section has excellent stretchability and heat setability, minimizing deterioration in processability, functionality, and physical properties due to dog-bone shape problems during spinning. The present invention relates to a composite fiber and a method for producing the same.

  Regarding polyester-based stretchable fibers, Patent Document 1 discloses a method using two types of polyethylene terephthalate (PET) having an intrinsic viscosity difference. Patent Document 2 and Patent Document 3 disclose a method for producing a polyester-based latent crimp-expressing fiber using general polyethylene terephthalate and highly shrinkable copolymer polyethylene terephthalate. In addition, Patent Document 4 and Patent Document 5 disclose a method of using polytrimethylene terephthalate (PTT) or polybutylene terephthalate (PBT) having stretch properties in polyethylene terephthalate (PET).

  However, in the case of the stretchable composite fiber in which the crimp produced by the production method described in the conventional patent is expressed, there is no special mention regarding the heat setting property, the heat stability, and the physical property change before and after the heat treatment. . In the case of general stretchable composite fibers, when heat set after treatment with no-load boiling water, the fixability is 70% level or less, and the elastic modulus and elongation change rate when stretched 10% before and after heat set Is 20% or more, the shape deformation is severely generated during the post-process or after the final processing, and it is difficult to set the conditions and to stabilize the dimensions at the time of product processing.

  In general, fiber products are subjected to a heat history of 130 to 190 ° C. and a tension of about 1 to 2 g / d during tentering. At this time, the heat setting properties of the yarn and the physical properties before and after the heat setting are performed. Changes are an important factor in determining the morphological stability of raw yarns and products. Therefore, in order to minimize the deformation of the raw yarn and product, the heat setability of the existing stretchable composite fiber is improved, and the elastic modulus and breaking elongation rate of the raw yarn before and after heat setting are minimized. Therefore, it is necessary to solve the problems of the prior art in which form deformation occurs in the subsequent process.

  The present inventors have recognized that the stability to heat set is closely related to the morphological stability of the raw yarn and the product, while the crimp elongation rate is 50% or more and the elastic recovery rate is 70% or more. Applicable to raw yarns and final products when the heat setability of fibers after no-load boiling water treatment is 80% or more, and the elastic modulus and elongation at break 10% before and after heat setting are 20% or less. Then, it turned out that form stability becomes excellent.

  In addition, the patents related to conventional stretchable composite fibers are mostly only proposed for composite spinning with different polyester polymers, and the physical properties of the composite fibers based on the molecular weight of the polymers of the different polymers constituting the composite fibers themselves. Is not mentioned. Patent Document 4 mentions changes in physical properties due to changes in viscosity of polyethylene terephthalate (PET), polytrimethylene terephthalate (PTT), and modified PET, PTT. There is no mention of the molecular weight of the different macromolecules that make up. Of course, the molecular weight can be estimated from the relationship between the viscosity and the molecular weight by the Mark-Houwink equation, but information on the molecular weight distribution cannot be obtained. Therefore, the present inventors have discovered that the molecular weight and molecular weight distribution of two types of polyester polymers having different viscosity differences are factors that affect the stretchability and heat setting properties of the fiber. The molecular weight and molecular weight distribution of the seed polymer were designed.

The composite fiber produced according to the present invention reduces the residence time of the polymer in the spin pack during spinning, minimizing molecular weight reduction, yarn properties and stretch properties, as shown in FIG. Using a spinneret and joining under the spinneret, as shown in FIG. 2 and FIG. 3, a side-by-side mold with a curved surface deformation index of 1.2 or less and a degree of deformity of 1.3 to 2.5 is used. By producing, compared with the existing eccentric core-sheath type yarn as shown in FIG. 4, the deterioration of the processability, functionality and physical properties due to the problem of the curved yarn during spinning was minimized. In addition, by the polymer and process characteristics, the heat setting property of the raw yarn is improved, the shape stability of the raw yarn and the product in the subsequent process is improved, and the strong elongation and stretch characteristics of the raw yarn are excellent. Therefore, it can be applied to various uses such as woven fabric, weft knitting and warp knitting.
Japanese Patent Laid-Open No. 10-72732 JP 2000-328378 A Japanese Patent Laid-Open No. 9-41234 U.S. Pat. No. 3,671,379 Japanese Patent Laid-Open No. 11-189923

  An object of the present invention is to provide a stretchable composite fiber excellent in heat setting property and shape stability of a product, and a method for producing the same, using an industrially usable fiber-forming polyester polymer. .

  Therefore, the present inventors have intensively studied to satisfy such a purpose, and as a result, among the fiber-forming polyester polymers, the difference in the number average molecular weight is 5,000 to 50,000. It can be seen that the composite fibers produced using different fiber-forming polymers having a distribution index of 1.5 to 2.5 have excellent stretchability, and each polymer has a number average molecular weight. The first component fiber-forming polyethylene terephthalate polymer having a molecular weight distribution index of 1.5 to 2.5, a number average molecular weight of 15,000 to 70,000, and a molecular weight distribution index of 10,000 to 20,000 The case where the second component fiber-forming polytrimethylene terephthalate polymer of 1.5 to 2.5 is an optimal polymer for minimizing the stretch properties and deformation during heat setting. I understoodWhen the difference in the number average molecular weight of the polymers is 5,000 or less, it is difficult to express the crimp elongation rate and elastic recovery rate of the raw yarn. When the difference is 50,000 or more, the molecular weight is decreased by increasing the spinning temperature. The effect cannot be expected due to deepening, and it is difficult to ensure processability due to the generation of bent yarns during spinning, and the heat setability is poor due to the increase in shrinkage effect due to high molecular weight. In addition, the molecular weight distribution index is limited to 1.5 to 2.5. If the molecular weight distribution index is smaller than 1.5, the molecular weight distribution becomes too uniform, and the self-plasticity of the low molecular weight substance (self- The role of plasticizing) becomes minor and prone to process problems. When the molecular weight distribution index is greater than 2.5, the molecular weight distribution increases and the effect of mixing several polymers is exhibited. Therefore, the problem that heat setting property and stretchability fall occurs.

  Also, in the case of a polymer having a high molecular weight, during spinning, the molecular weight is greatly reduced due to thermal decomposition, and the molecular weight distribution is also widened. Therefore, the residence time of the polymer melt in the spinning pack is minimized to 5 minutes or less. As a result, it has been found that the expression of physical properties and functionality due to the above characteristics can be maximized.

  Further, when the curved surface deformation index between polymers in the cross section of the raw yarn exceeds 1.2, the generation of bent yarn becomes severe during spinning, which causes a problem in processability, which causes a decrease in stretchability. Such a tendency is more severe when the cross-sectional shape is an eccentric core-sheath type as shown in FIG. Therefore, in the present invention, in order to improve the processability and functionality of the production of stretchable composite fibers, a process of joining under a spinneret using two kinds of fiber-forming polyester polymers is used, and FIG. In this case, the yarn is produced in a side-by-side (joint type) form, and at this time, the curved surface deformation index between polymers of the raw yarn cross section is 1.2 or less, and the degree of deformation is 1.3 to 2.5. And

  As another aspect of the present invention, in the case of stretchable composite fibers by melt spinning, the fabric is severely reduced during the post-process, and it is difficult to set conditions during product processing, and shape deformation occurs even after final processing. Therefore, it is difficult to stabilize the dimensions of the sewn product, which is caused by the heat setting property of the stretchable yarn and the change in physical properties of the yarn before and after the heat setting. In general, fiber products are subjected to a heat history of 130 to 190 ° C. and a tension of about 1 to 2 g / d during tentering, but the heat setting property of the raw yarn is the shape stability of the raw yarn and the product. Is an important factor to determine. Therefore, in order to minimize the deformation of the product, the present invention has a fixing property of 80% or more when heat-set after treatment with no-load boiling water, and an elastic modulus and elongation at break of 10% before and after heat setting. The object of the present invention is to minimize the deformation of the shape in the subsequent process by manufacturing the change rate to be 20% or less.

  In the present invention, the first component is a composite fiber made of polyethylene terephthalate and the second component is polytrimethylene terephthalate, and the crimp elongation at the time of no-load boiling water treatment is 50% or more, and the elastic recovery rate is 70%. As described above, a composite fiber excellent in heat setting property and stretchability is provided in which the heat setting property is 80% or more, and the elastic modulus at the time of stretching 10% before and after heat setting and the rate of change in breaking elongation is 20% or less.

  Moreover, it is preferable that the cross-sectional form is a side-by-side form, the curved surface deformation index is 1.2 or less, and the cross-sectional deformity (a / b) is 1.3 to 2.5.

  The one kind of polymer is polyethylene terephthalate, the number average molecular weight is 10,000 to 20,000, the molecular weight distribution index is 1.5 to 2.5, and the other one kind of polymer is polytriethylene. Methylene terephthalate having a number average molecular weight of 15,000 to 70,000, a molecular weight distribution index of 1.5 to 2.5, and a difference in number average molecular weight between the two polymers of 5,000 to 50,000. Is preferred.

  In the present invention, (A) one kind of polymer is polyethylene terephthalate, the number average molecular weight is 10,000 to 20,000, the molecular weight distribution index is 1.5 to 2.5, and the other one kind. The polymer is a polytrimethylene terephthalate having a number average molecular weight of 15,000 to 70,000, a molecular weight distribution index of 1.5 to 2.5, and a difference in number average molecular weight between the two polymers of 5,000 to A step of melting two kinds of polyesters of 50,000, and (B) after passing the melt through the spin pack so that the residence time in the spin pack is 5 minutes or less, After drawing into a composite yarn having a spinning speed of 4,000 m / min, a side-by-side configuration, a curved surface deformation index of 1.2 or less, and a cross-section irregularity (a / b) of 1.3 to 2.5, and then drawing And heat fixing process To provide a method for manufacturing a composite fiber with excellent thermal setting properties and stretchability is produced by.

  Moreover, it is preferable that the manufacturing method of the elastic composite fiber of this invention is manufactured by the partial orientation-drawing / false twist method.

  Moreover, it is preferable that the said extending | stretching temperature is 85-95 degreeC, and the heat setting temperature is 130-200 degreeC.

  Further, at the time of spinning, it is preferable that the bending angle from the direction perpendicular to the surface of the base immediately below the spinneret is 20 ° or less.

  Moreover, this invention provides the processed yarn which is manufactured from the said elastic composite fiber and has a twist number (TM: Twist / meter) of 150-2,000.

  The present invention also provides a blended yarn in which the stretchable composite fiber is mixed with an original yarn having a high shrinkage property having an elongation of 50% or more and a boiling water shrinkage of 15% or more.

  Moreover, this invention provides the fabric containing the said elastic composite fiber.

  The stretchable conjugate fiber produced by the present invention has a high stretchability of 50% or more crimp extension rate and 70% or more elastic recovery rate, and has a heat setting property of 80% or more after no-load boiling water treatment, Since the elastic modulus at 10% elongation before and after heat setting and the rate of change in elongation at break are 20% or less, the product stability at the time of raw yarn and post-processing is extremely excellent. In addition, the composite fiber produced according to the present invention reduces the residence time of the polymer in the spinning pack during spinning, thereby minimizing the decrease in molecular weight, the properties of the yarn, and the stretch properties. Compared to the above, by improving the heat setting property and minimizing the rate of change of the elastic modulus and elongation at break when stretched by 10% before and after heat setting, the shape stability of the product at the subsequent process was achieved. In addition, the shape of the cross section is a side-by-side type, the curved surface deformation index is 1.2 or less, and the cross section deformation degree is 1.3 to 2.5 level. Furthermore, since the raw yarn has excellent extensibility, heat setability, stretchability, etc., it can be applied to various uses such as woven fabric, weft knitting and warp knitting.

  In order to produce the composite fiber of the present invention in which the heat setting property of the raw yarn and the product is improved, the number average molecular weight difference is 5,000 to 50,000, and the molecular weight distribution index is 1.5 to 2. It is preferable to use different fiber-forming polyester polymers of No. 5, with regard to the characteristics of each polymer, its analysis method, and production method, the polymer material and the spinning process using this will be described as follows. To do.

  (1) Characteristics of different fiber-forming polyester polymers having a number average molecular weight difference of 5,000 to 50,000 and a molecular weight distribution index of 1.5 to 2.5, and an analysis method thereof

  The two types of polymers used in the present invention have a number average molecular weight difference of 5,000 to 50,000 and a molecular weight distribution index of 1.5 to 2.5. The number average molecular weight of the one component polyethylene terephthalate polymer must be 10,000 to 20,000, the molecular weight distribution index must be 1.5 to 2.5, and the number of the second component polytrimethylene terephthalate polymer The average molecular weight should be 15,000-70,000 and the molecular weight distribution index should be 1.5-2.5.

  In the present invention, as the polymer, polyethylene terephthalate having a number average molecular weight of 10,000 to 20,000 and a molecular weight distribution index of 1.5 to 2.5 is used as the first component polymer. As the polymer, polytrimethylene terephthalate having a number average molecular weight of 15,000 to 70,000 and a molecular weight distribution index of 1.5 to 2.5 was used.

  These polymers are produced from generally known bulk polymerization, solution polymerization, interfacial polymerization, etc., and the polymer targeted by the present invention can be used by any of these methods, and is particularly preferred. Among the bulk polymerization methods, a polymer produced from melt polymerization or solid polymerization is advantageous in terms of production cost.

  In the present invention, the reason why the minimum molecular weight of the low molecular weight polyethylene terephthalate polymer is 10,000 and the maximum molecular weight of the high molecular weight polyethylene terephthalate polymer is 70,000 is as follows. It is not difficult as a polymerization method itself to produce a polymer having a molecular weight of less than 10,000. However, in order to fiberize using this polymer, it is advantageous to be in the form of chips (or pellets). If the molecular weight is less than 10,000, it is too fragile when manufactured into a chip, which makes it difficult to manufacture a chip having a uniform shape. When the molecular weight exceeds 70,000, not only is the polymerization time too long, which is economically disadvantageous, but the spinning temperature must be excessively increased, and therefore the effect cannot be expected due to the decrease in molecular weight due to thermal decomposition.

  In addition, the molecular weight distribution index is limited to 1.5 to 2.5 if the molecular weight distribution index is less than 1.5, the molecular weight distribution becomes too uniform, and the self-plasticizing of low molecular weight substances. ) Will be subtle and prone to process problems. If the molecular weight distribution index is greater than 2.5, the molecular weight distribution will increase and the effect of mixing several polymers will be manifested. For this reason, there arises a problem that the heat setting property and the stretchability are lowered.

  In the present invention, the number average molecular weight and molecular weight distribution index are obtained by dissolving a polymer or a produced composite fiber in hexafluoroisopropyl alcohol (HFIP) and using a high-temperature GPC set of Waters, USA. Then, the number average molecular weight (Mn) and the weight average molecular weight (Mw) are measured using polystyrene as a reference substance, and the molecular weight distribution index (Polydispersity) is calculated from the following equation (1). Index, PDI) was converted.

  (2) Manufacture of composite fiber

  The spinning temperature of the polymer during melt spinning for producing the conjugate fiber was 20 to 70 ° C. higher than the melting temperature of each polymer. If the spinning temperature of the polymer is not higher than the melting temperature of the polymer by 20 ° C. or more, it is melted non-uniformly, the pressure in the extruder becomes too high, and the workability is lowered. This is not preferable because problems such as non-uniformity occur. If the spinning temperature of the polymer is higher than the melting temperature of the polymer by more than 70 ° C., the flowability of the polymer is improved, but problems such as thermal decomposition of the polymer occur, which is not preferable.

  A composite fiber having a side-by-side cross section can be produced by joining the discharged individual fibrous polymers directly under the spinneret of FIG. The gradient of the discharge holes of the spinneret used in the present invention is preferably 10 to 30 ° as shown in FIG. If the gradient of the discharge holes is less than 10 °, it is difficult to solve the problem of bent yarn generation when spinning using two kinds of polymers having different molecular structures and molecular weight differences, and exceeds 30 °. This is not preferable because a non-uniform phenomenon occurs in the cross section of the raw yarn, which may adversely affect the quality and processability of the raw yarn.

  Further, the problem of the bending yarn caused by the difference in molecular weight and viscosity at the time of spinning of the eccentric core-sheath type composite fiber spun together and spun in the spinning pack is shown in FIG. 2 and FIG. As shown in FIG. 3, the problem can be solved by adjusting the curved surface deformation index between polymers of the raw yarn cross section to 1.2 or less and the degree of deformation to 1.3 to 2.5.

  In the case of a polymer having a high molecular weight, the inventors of the present invention have a great decrease in the molecular weight due to thermal decomposition during spinning, and the molecular weight distribution is also widened. Therefore, the residence time of the polymer melt in the spinning pack is It was found that the expression of physical properties and functionality due to the above characteristics can be maximized by minimizing the length to 5 minutes or less.

  The obtained conjugate fiber can be made into a fiber by a partially oriented yarn-drawn / false twist method used for production of a normal polyester conjugate fiber.

  A core technical component of the present invention includes a spinning speed of 2,200 to 4,000 m / min. This is not only disadvantageous in terms of economy, but also due to an increase in the draw ratio at the time of drawing, when spinning at a spinning speed of less than 2,200 m / min, due to a decrease in the discharge amount of the polymer melt due to low speed spinning. This is because an increase in the heat shrinkage rate ultimately lowers the heat setting properties of the raw yarn and the product, and the shape stability of the final product with respect to heat decreases sharply. In general, fibers having crystals formed by high-stretch drawing at a low spinning speed exhibit a high shrinkage rate against heat. In addition, when spinning at a spinning speed exceeding 4,000 m / min, the stability of the spinning process is reduced due to a decrease in spinnability due to too different thermal and physical properties between two different molecular weight polymers. Therefore, it is not preferable.

  The present invention is characterized in that, as another core technical component, when it is produced by a partial orientation-stretching / false twisting method, the stretching temperature is 85 to 95 ° C and the heat setting temperature is 130 to 200 ° C. . When the stretching temperature is less than 85 ° C., uniform stretching is difficult, and when it exceeds 95 ° C., the degree of plasticization by heat becomes severe, and the inter-spinning process property and its physical properties become unstable. When the heat setting temperature is less than 130 ° C, the heat shrinkage rate of the raw yarn and the product increases and the shape stability is deteriorated. When it exceeds 200 ° C, plasticization becomes severe and process properties and various physical properties are weakened. This is not preferable.

  In the case of the conventional stretchable conjugate fiber, the reduction of the fabric during the post-process is usually 10% or more, and the heat setting property is inferior, and the shape deformation occurs. There is a problem that it is difficult to stabilize the dimensions of the sewn product. A general textile product usually receives a heat history of 130 to 190 ° C. and a tension of about 1 to 2 g / d during weaving / dyeing and heat setting. The present inventors have found that there is a close relationship with the shape stability, the heat setability of the raw yarn after the no-load boiling water treatment is 80% or more, the elastic modulus and elongation at break when stretching 10% before and after heat setting. It has been found that when the rate of change of the degree is 20% or less, it is possible to minimize the shape deformation in the subsequent process.

  Table 1 shows the physical properties and functionality of the fibers according to the yarn production conditions of the present invention.

  Hereinafter, the present invention will be described in more detail based on the following examples. The following examples merely illustrate the invention and do not limit the scope of the invention.

  First, an evaluation standard of physical properties of a bonded composite fiber manufactured by the method according to the present invention and a measuring method thereof will be described.

(1) Method for measuring number average molecular weight and molecular weight distribution A polymer is dissolved in hexafluoroisopropyl alcohol (HFIP), and a high temperature GPC set of Waters (USA) is used to produce polystyrene. ) As the reference substance, the number average molecular weight (Mn) and the weight average molecular weight (Mw) are measured, and the molecular weight distribution index (PDI) is converted from the following equation (1). did.

(2) Measuring method of crimp extension rate and elastic recovery rate In order to measure the crimp extension rate and elastic recovery rate, which are the physical properties of the crimp-forming composite fibers produced in the examples, the following procedure was performed.

The fiber bundle was immersed in boiling water for 30 minutes under no load, and then dried at room temperature. After applying a load of 0.1 g / d for 2 minutes, it was deweighted and left for 10 minutes. The sample that had undergone the above steps was allowed to stand for 2 minutes under a load of 0.002 g / d, and the length (L ₁ ) at that time was measured. A load of 0.1 g / d was applied to the sample, and after 2 minutes, the length (L ₂ ) was measured. Then, the load (0.1 g / d) was removed, and after 2 minutes, the length (L ₃ ) at that time was measured. The crimp extension rate and elastic recovery rate were calculated by the following formulas (2) and (3).

Crimp elongation (%) = [(L ₂ −L ₁ ) / L ₂ ] × 100 (2)

Elastic recovery rate (%) = [(L ₂ −L ₃ ) / (L ₂ −L ₁ )] × 100 (3)

(3) Measuring method of heat setting property After boiling and hydrothermal treatment for 30 minutes under no load and natural drying, the length (T ₁ ) of the fiber was measured under its own weight. After the fiber was stretched and fixed by 50%, the length (T ₂ ) was measured, and then heat set at 130 ° C. for 30 minutes. After cooling to room temperature, the fixation was dismantled, the length (T ₃ ) of the raw yarn was measured, and the heat setting property of the fiber was calculated by the following equation (4).

Thermal setting property (%) = [(T ₃ −T ₁ ) / (T ₂ −L ₁ )] × 100 (4)

(4) Measuring method of change rate of elastic modulus and breaking elongation at 10% elongation After boiling hydrothermal treatment for 30 minutes under no load, the elastic modulus and breaking elongation at 10% elongation of the raw yarn before and after heat setting Using an Instron 5565 manufactured by Instron, measurement was performed under the conditions of 20 ° C., relative humidity 65%, and initial load 0.002 g / d. The rate of change is expressed as a percentage (%) of the change rate of the elastic modulus and elongation at break 10% after heat setting with respect to the modulus of elasticity and elongation at break 10% before heat setting. Displayed as in 6).

  Rate of change of elastic modulus before and after heat setting (%) = [(elastic modulus at 10% extension after heat setting−elastic modulus at 10% extension before heat setting) / (elastic modulus at 10% extension before heat setting)] × 100 (5)

  Change rate of breaking elongation before and after heat setting (%) = [(breaking elongation after heat setting−breaking elongation before heat setting) / (breaking elongation before heat setting)] × 100 (6)

(5) Method for measuring bent yarn deformation angle The degree to which the yarns merged just below the spinneret were folded from the direction perpendicular to the surface of the spinneret was indicated by an angle (°) (FIG. 5).

(6) Curved surface deformation index and deformity of raw yarn cross section As shown in FIGS. 2, 3 and 4, after analyzing the cross section of the raw yarn with a scanning electron microscope (SEM), the following equations (7) and (8) Displayed by.

  Curved surface deformation index = c / d (7)

  Deformity = a / b (8)

Example 1
In producing elastic conjugate fibers, polyethylene terephthalate having a number average molecular weight (Mn) of 12,632 and a molecular weight distribution index (PDI) of 2.2, a number average molecular weight (Mn) of 19,149, a molecular weight distribution index (PDI) of 2 .4 polytrimethylene terephthalate at a weight ratio of 5: 5, using a conventional melt-combined spinning facility, with a side-by-side cross section of FIG. 2- (a), a spinning temperature of 270 ° C., a spinning speed of 2,600 m / And a residence time of 4 minutes in the pack, a polyester composite fiber was produced so that the curved surface deformation index was 1.10, the cross-sectional deformity was 1.7, and the single yarn fineness was 3.4 denier. The composite fiber obtained by spinning / winding was drawn using a separate drawing device to produce a stretchable composite fiber having a single yarn fineness of 2.1 denier. The stretching ratio at the time of stretching was 1.70, the stretching temperature was 85 ° C., and the heat setting temperature was 155 ° C. The results are shown in 1. The obtained fiber had a small bending deformation angle at the time of spinning, and exhibited excellent heat setting properties and stretching properties.

(Example 2)
In producing elastic conjugate fibers, polyethylene terephthalate having a number average molecular weight (Mn) of 12,632 and a molecular weight distribution index (PDI) of 2.2, a number average molecular weight (Mn) of 33,522, a molecular weight distribution index (PDI) of 2 .1 polytrimethylene terephthalate at a weight ratio of 5: 5 by using a conventional melt-combined spinning equipment, with a side-by-side cross section of FIG. 2- (a), a spinning temperature of 275 ° C., a spinning speed of 2,600 m / And a residence time in the pack of 4 minutes, a polyester composite fiber was produced so that the curved surface deformation index was 1.10, the profile irregularity was 1.9, and the single yarn fineness was 3.4 denier. The composite fiber obtained by spinning / winding was drawn using a separate drawing device to produce a stretchable composite fiber having a single yarn fineness of 2.1 denier. The drawing ratio was 1.70, the drawing temperature was 90 ° C., and the heat setting temperature was 160 ° C. The results are shown in Table 1. The obtained fiber had a small bending deformation angle at the time of spinning, and exhibited excellent heat setting properties and stretching properties.

(Example 3)
In producing elastic conjugate fibers, polyethylene terephthalate having a number average molecular weight (Mn) of 15,385 and a molecular weight distribution index (PDI) of 2.2, a number average molecular weight (Mn) of 45,589, a molecular weight distribution index (PDI) of 2 .2 polytrimethylene terephthalate at a weight ratio of 5: 5 by using a conventional melt-combined spinning equipment, with a side-by-side cross section of FIG. 2- (a), a spinning temperature of 280 ° C., a spinning speed of 2,400 m / And a residence time in the pack of 4 minutes, a polyester composite fiber was produced so that the curved surface deformation index was 1.10, the cross-sectional deformity was 1.8, and the single yarn fineness was 3.4 denier. The composite fiber obtained by spinning / winding was drawn using a separate drawing device to produce a stretchable composite fiber having a single yarn fineness of 2.1 denier. The drawing ratio was 1.70, the drawing temperature was 90 ° C., and the heat setting temperature was 160 ° C. The results are shown in Table 1. The obtained fiber had a small bending deformation angle at the time of spinning, and exhibited excellent heat setting properties and stretching properties.

Example 4
In the production of elastic conjugate fibers, polyethylene terephthalate having a number average molecular weight (Mn) of 15,385 and a molecular weight distribution index (PDI) of 2.2, a number average molecular weight (Mn) of 63,312 and a molecular weight distribution index (PDI) of 2 0.0 polytrimethylene terephthalate at a weight ratio of 6: 4, using a conventional melt-combined spinning facility, with a side-by-side cross section of FIG. 2- (b), a spinning temperature of 285 ° C., a spinning speed of 2,200 m / And a residence time in the pack of 4 minutes, a polyester composite fiber was produced so that the curved surface deformation index was 1.15, the cross-sectional deformity was 1.8, and the single yarn fineness was 3.4 denier. The composite fiber obtained by spinning / winding was drawn using a separate drawing device to produce a stretchable composite fiber having a single yarn fineness of 2.1 denier. The stretching ratio at the time of stretching was 1.62, the stretching temperature was 90 ° C., and the heat setting temperature was 180 ° C. The results are shown in Table 1. The obtained fiber had a small bending deformation angle at the time of spinning, and exhibited excellent heat setting properties and stretching properties.

(Comparative Example 1)
In producing elastic conjugate fibers, polyethylene terephthalate having a number average molecular weight (Mn) of 12,632 and a molecular weight distribution index (PDI) of 2.2, a number average molecular weight (Mn) of 16,950, a molecular weight distribution index (PDI) of 2 .4 polytrimethylene terephthalate at a weight ratio of 5: 5, using a conventional melt-combined spinning facility, with a side-by-side cross section of FIG. 2- (a), a spinning temperature of 270 ° C., a spinning speed of 2,600 m / And a residence time in the pack of 4 minutes, a polyester composite fiber was produced so that the curved surface deformation index was 1.10, the cross-sectional deformation was 1.6, and the single yarn fineness was 3.4 denier. The composite fiber obtained by spinning / winding was drawn using a separate drawing device to produce a stretchable composite fiber having a single yarn fineness of 2.1 denier. The stretching ratio during stretching was 1.70, the stretching temperature was 85 ° C., and the heat setting temperature was 145 ° C. The results are shown in Table 1. The obtained fiber had a small bending deformation angle at the time of spinning, but exhibited a decrease in heat setting property and stretch property.

(Comparative Example 2)
In the production of elastic conjugate fibers, polyethylene terephthalate having a number average molecular weight (Mn) of 12,632 and a molecular weight distribution index (PDI) of 2.2, a number average molecular weight (Mn) of 24,411, a molecular weight distribution index (PDI) of 2 .7 polytrimethylene terephthalate at a weight ratio of 5: 5 using a conventional melt composite spinning equipment, with an eccentric core-sheath section of FIG. 4, a spinning temperature of 270 ° C., a spinning speed of 2,600 m / min. The polyester composite fiber was manufactured so that the residence time in the pack was set to 8 minutes, and the curved surface deformation index was 1.55, the cross-sectional deformity was 1.0, and the single yarn fineness was 3.4 denier. The composite fiber obtained by spinning / winding was drawn using a separate drawing device to produce a stretchable composite fiber having a single yarn fineness of 2.1 denier. The stretching ratio during stretching was 1.70, the stretching temperature was 85 ° C., and the heat setting temperature was 140 ° C. The results are shown in Table 1. The obtained fiber had a large bent yarn deformation angle during spinning, and exhibited a decrease in heat setting property and stretching property.

(Comparative Example 3)
In the production of elastic conjugate fibers, polyethylene terephthalate having a number average molecular weight (Mn) of 12,632 and a molecular weight distribution index (PDI) of 2.2, a number average molecular weight (Mn) of 31,290, a molecular weight distribution index (PDI) of 2 .8 polytrimethylene terephthalate at a weight ratio of 5: 5 using a conventional melt-combined spinning equipment, with a side-by-side cross section of FIG. 2- (a), a spinning temperature of 275 ° C., a spinning speed of 1,400 m / And a residence time in the pack of 8 minutes, a polyester composite fiber was produced so that the curved surface deformation index was 1.20, the profile irregularity was 1.7, and the single yarn fineness was 6.0 denier. The composite fiber obtained by spinning / winding was drawn using a separate drawing device to produce a stretchable composite fiber having a single yarn fineness of 2.1 denier. The stretching ratio during stretching was 2.90, the stretching temperature was 75 ° C., and the heat setting temperature was 145 ° C. The results are shown in Table 1. The obtained fiber had a small bending deformation angle at the time of spinning, but exhibited a decrease in heat setting property and stretch property.

It is sectional drawing of the spinneret used by this invention. (A)-(c) is sectional drawing of the composite fiber excellent in the elasticity and heat setting property manufactured by this invention. 1 is a diagram illustrating a curved surface deformation index and a deformed view of a stretchable fiber manufactured according to the present invention. It is drawing which shows the curved surface deformation | transformation index | exponent and deformity of an eccentric core-sheath-type elastic fiber. It is drawing which shows the bending thread deformation angle at the time of manufacture of the elastic fiber by this invention.

Claims (5)

The first component is polyethylene terephthalate, the second component is a composite fiber made of polytrimethylene terephthalate, and the polyethylene terephthalate has a number average molecular weight of 10,000 to 20,000 and a molecular weight distribution index of 1.5 to 2.5, the polytrimethylene terephthalate has a number average molecular weight of 15,000 to 70,000, a molecular weight distribution index of 1.5 to 2.5, and the polyethylene terephthalate and the polytrimethylene terephthalate The difference in the number average molecular weight is 5,000 to 50,000,
(A) melting the polyethylene terephthalate and the polytrimethylene terephthalate;
(B) A side-by-side composite yarn at a spinning speed of 2,200 to 4,000 m / min after passing the melt through the spinning pack so that the residence time in the spinning pack is 5 minutes or less. The process of taking over
(C) The drawn composite yarn is produced by a method including a drawing temperature of 85 to 95 ° C and a heat setting temperature of 130 to 200 ° C, and has the following physical properties. heat setting property and stretchability superior composite fiber to.
(1) Deformation degree of the cross section of the composite fiber (a / b) 1.3 to 2.5, (2) Crimp elongation at the time of no-load boiling water treatment calculated by the following formula (2) is 50% or more 70% or less , (3) The elastic recovery rate calculated by the following formula (3) is 70% or more and 90% or less , (4) The heat setting property calculated by the following formula (4) is 80% or more and 95% or less , (5) Change rate of elastic modulus and elongation at break when stretched 10% before and after heat setting is 20% or less.
Crimp elongation (%) = [(L ₂ −L ₁ ) / L ₂ ] × 100 (2),
Elastic recovery rate (%) = [(L ₂ −L ₃ ) / (L ₂ −L ₁ )] × 100 (3),
(In the above formulas (2) and (3), L ₁ is obtained by immersing the fiber bundle in boiling water for 30 minutes under no load, then drying at room temperature, and applying a load of 0.1 g / d for 2 minutes. after the addition, was subjected to standing stages unloading to 10 minutes a sample was allowed to stand for 2 minutes under a load of 0.002 g / d, a value obtained by measuring the length (L ₁₎ at that time, L ₂ Is a value obtained by applying a load of 0.1 g / d to the sample and measuring the length (L ₂ ) after 2 minutes . L ₃ is a value obtained by removing a load of 0.1 g / d from the L ₂ measurement. 2 minutes later, the length (L ₃ ) measured at that time)
Thermal setting property (%) = [(T ₃ −T ₁ ) / (T ₂ −L ₁ )] × 100 (4)
(In the above formula (4), T ₁ is a value obtained by measuring the fiber length (T ₁ ) under its own weight after naturally drying by boiling hydrothermal treatment for 30 minutes under no load , and T ₂ is: After the fiber was stretched and fixed by 50%, the length (T ₂ ) was measured, and L ₃ was measured after T ₂ , heat-set at 130 ° C. for 30 minutes, and cooled to room temperature. This is a value obtained by disassembling the fixing and measuring the length (T ₃ ) of the raw yarn ). (B) the time of spinning in the step immediately below the spinning between the spinneret, songs yarn deformation angle from perpendicular direction of the base surface according to claim 1 of the heat setting property and stretchability of wherein a is 20 ° or less Excellent composite fiber.   A processed yarn produced from the stretchable conjugate fiber according to claim 1 and having a twist number (TM: Twist / meter) of 150 to 2,000.   A blended yarn comprising the stretchable conjugate fiber according to claim 1 and a yarn having a high shrinkage characteristic of 50% elongation or more and a boiling water shrinkage of 15% or more.   A fabric comprising the composite fiber excellent in heat setting property and stretchability according to claim 1.

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