KR100531617B1 - Conjugated fiber and manufacturing thereof - Google Patents

Abstract

The present invention relates to a crimp-forming composite fiber having excellent elasticity and improved product stability in post-processing, and a method of manufacturing the same. More specifically, the present invention is very stable in thermal history, tension, and the like received by knitting and dyeing. The present invention relates to a crimp-forming composite fiber of a side-by-side type or a heath-core type. The elastic composite fiber prepared according to the present invention has a high elasticity of 40% or more, an elastic recovery rate of 70% or more, and a maximum heat shrinkage stress temperature of 155 ° C or higher, so the iron shrinkage of the final fabric is less than 3%. As a result, it can be said that the stability of the product during the post-processing is very excellent. In addition, the polymer used in the present invention is characterized by using different fiber-forming polymers having a difference in number average molecular weight of 5,000 to 70,000 and a molecular weight distribution index of 1.5 to 2.5.

The composite fiber produced according to the present invention can be melt-spun like general melt-spun synthetic fibers and can be produced by a conventional composite spinning equipment without problems such as solvent recovery. In addition, by reducing the polymer residence time in the spin pack between yarns, molecular weight reduction, yarn properties and elasticity deterioration were minimized, and the maximum heat shrinkage stress temperature was improved compared to the existing yarns to improve the shape stability of the product during post-processing. It has excellent elasticity characteristics and can be applied to various purposes such as fabric, circular knitting, and warp knitting.

Description

Composite fiber and manufacturing method thereof

The present invention relates to a crimp-forming composite fiber having excellent elasticity and improved product stability at post-processing, and a method of manufacturing the same. More specifically, the present invention relates to a crimp elongation of 40% or more and an elastic recovery rate of 70% or more. Although it has a maximum heat shrinkage stress of 155 ° C or higher, it is a side-by-side or heat-core type crimp that is very stable to the heat history and tension received during weaving and dyeing. The present invention relates to a forming composite fiber and a method for producing the same.

Japanese Patent Application Laid-Open No. 10-72732 discloses a method of using two kinds of polyethylene terephthalate (PET) having extreme viscosity differences. In addition, Japanese Patent Laid-Open No. 2000-328378 and Japanese Patent Laid-Open No. 9-41234 prepare polyester-based latent crimp-expressing fibers using general polyethylene terephthalate and highly shrinkable copolymerized polyethylene terephthalate. Methods are known. In addition, U.S. Patent No. 3,671,379 and Japanese Patent Application Laid-Open No. 11-189923 use polytrimethylene terephthalate (PTT) or polybutylene terephthalate (PBT) having a stretch property to polyethylene terephthalate (PET). It also shows how to do it.

However, in the case of the crimp-expressing stretchable composite fiber produced according to the manufacturing method described in the above-mentioned conventional patents, the shrinkage of the fabric is usually 10% or more during post-processing, and 3% or more in iron even after the final processing. Shape deformation occurs, so that the conditions are difficult to set during processing, it is difficult to stabilize the dimensions of the product. In general, textile products are subjected to a thermal history of 130 to 190 ° C and a tension of about 1 to 2 g / d during weaving / dyeing, thermal setting, and iron. It is an important factor in determining dignity. Therefore, in order to minimize the shape deformation caused by the iron of the product, it is necessary to solve the problem of the conventional technology that more than 3% of the shape deformation occurs in the iron (Iron).

The inventors have found that the shrinkage that occurs during ironing of the fabric is closely related to the maximum heat shrinkage stress of the fiber. When the maximum heat shrinkage stress of the fiber is 155 ° C or higher, the iron shrinkage of the fabric is less than 3%. It has been found that the shape stability of the final product is excellent.

In addition, the conventional patent, Japanese Patent Laid-Open Publication No. 2002-54030 describes that the maximum heat shrinkage stress temperature is 130 ° C. or lower, and the maximum heat shrinkage stress peak value is 0.20 cN / dtex or more. There is no mention. In general, in the case of elastic fiber products compared to general fibers, morphological stability is a problem because it is sensitive to thermal history and tension during weaving / dying, thermal setting, and iron. This has an important effect on the uniformity of dyeing of products, the processing of cheap papers and dimensional stability of sewing products. In general, if the iron shrinkage ratio is 3% or more, the product quality is considered to be poor.

In addition, the conventional stretchable composite fiber patents are mostly proposed only for the composite spinning by different polyester polymers, and mention the physical properties of the composite fiber by the molecular weight of the polymer itself of the different polymers constituting the composite fiber. Not. U.S. Patent No. 3,671,379 mentions a change in properties due to a change in viscosity for polyethylene terephthalate (PET), polytrimethylene terephthalate (PTT) and modified PET, PTT, but this patent also comprises There is no mention of the molecular weight of different polymers. Of course, it is possible to estimate the molecular weight in the viscosity-molecular weight relationship by the Mark-Hawink equation, but no information on the molecular weight distribution can be obtained. In addition, it also refers to stretchable composite fibers using polyester polymers having different viscosity differences between PTTs or different types such as PTT-PET and PTT-PBT, but there is no information on molecular weight and molecular weight distribution. The present inventors found that the molecular weight, molecular weight distribution and heat setting temperature at the time of stretching of polyester polymers having different viscosity differences are factors that influence the maximum heat shrinkage stress temperature, stretch characteristics, and iron shrinkage rate of the fabric. And designed the molecular weight and molecular weight distribution of the optimal two polymers.

The present inventors aim to produce a crimp-forming composite fiber having excellent elasticity and excellent shape stability of the product by using a fiber-forming polymer which can be used industrially.

Therefore, the present inventors earnestly researched to meet these objectives. Among the fiber-forming polymers, the present inventors used different fiber-forming polymers having a difference in number average molecular weight of 5,000 to 70,000 and each molecular weight distribution index of 1.5 to 2.5. It was found that the composite fiber produced was excellent in elasticity, and each of the polymers had a fiber-forming polymer of a first component having a number average molecular weight of 10,000 to 20,000 and a molecular weight distribution index of 1.5 to 2.5, a number average molecular weight of 15,000 to 90,000, and a molecular weight distribution. It was found that the composition of the second fiber-forming polymer having an index of 1.5 to 2.5 is an optimal polymer for minimizing elastic properties and ironic shape deformation. If the number average molecular weight difference of the polymer is less than 5,000, it is difficult to express the crimp elongation and elastic recovery rate of the yarn, and if it is more than 70,000, it is difficult to expect the effect due to the decrease of the molecular weight due to the high temperature of the spinning temperature. It is difficult and has a disadvantage in that the iron shrinkage rate is poor due to the increase in the shrinkage effect due to the high molecular weight. If 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 role of low-molecular weight self-plasticizing tends to be insufficient. When the molecular weight distribution is greater than 2.5, the molecular weight distribution becomes large, and the effect of mixing various polymers is expressed. When the heat setting temperature is raised above a certain level, plasticization occurs in the hot plate, ultimately the maximum heat shrinkage stress temperature. It becomes difficult to raise the problem that the shape stability and elasticity is degraded.

In addition, in the case of a polymer having a high molecular weight, the molecular weight decrease due to inter-spinning pyrolysis is increased, and the molecular weight distribution is also widened, thereby minimizing the residence time of the polymer melt in the spin pack to 5 minutes or less, thereby exhibiting the properties and functional expression according to the above characteristics. I found that it can be maximized. In another aspect of the present invention, in the case of the stretchable composite fiber by melt spinning, the shrinkage of the fabric is usually 10% or more during post-processing, and 3% or more of shape deformation occurs even after the final processing, so that the conditions for setting the product are difficult. It has been found that it is difficult to stabilize the dimensions of an article. Common textile products are usually subjected to thermal history of 130 ~ 190 ℃ and tension of 1 ~ 2g / d during weaving / dyeing, thermal setting and iron. It should be within 3%, and this characteristic is found to be closely related to the maximum heat shrinkage stress temperature of the fiber, and when the maximum heat shrinkage stress temperature is increased to 155 ° C or higher, the shape stability of the elastic product is excellent.

The present invention has a maximum heat shrinkage stress temperature of 155 ° C or higher, a crimp elongation of 40% or more, and an elastic recovery rate of 70% or more under unloaded non-water treatment. (Iron) Provides a stretchable composite fiber excellent in shape stability, characterized in that to provide a processed fabric having a shrinkage of 3% or less.

In addition, the first polymer is polyethylene terephthalate with a number average molecular weight of 10,000 to 20,000, the molecular weight distribution index is 1.5 to 2.5, and the other polymer is polytrimethylene terephthalate with a number average molecular weight of 15,000 to 90,000, The molecular weight distribution index is 1.5 to 2.5, and the number average molecular weight difference of the two polymers is characterized by 5,000 to 70,000.

In addition, one polymer is a polyethylene terephthalate having a number average molecular weight of 10,000 to 20,000, a molecular weight distribution index of 1.5 to 2.5, and another polymer is a polyethylene terephthalate, polybutylene terephthalate or polyethylene terephthalate copolymer. As a result, the number average molecular weight is 15,000 to 90,000, the molecular weight distribution index is 1.5 to 2.5, and the number average molecular weight difference of the two polymers is 5,000 to 70,000.

In addition, the cross-sectional shape is preferably a side-by-side type or an eccentric sheath-core type.

Moreover, it is preferable that the diameter of a crimp is 8 mm or less.

In addition, the present invention (A) one polymer is a polyethylene terephthalate number average molecular weight of 10,000 to 20,000, molecular weight distribution index of 1.5 to 2.5, another polymer is a polytrimethylene terephthalate number average molecular weight (1) melting the two polyesters having a molecular weight distribution index of 15,000 to 90,000 and a molecular weight distribution index of 1.5 to 2.5; and (B) passing the melt through a spinning pack such that the residence time in the spinning pack is 5 minutes or less, and then the spinning speed is increased. Prepared by a method comprising drawing into a composite yarn of Side-By-Side or Heath-Core type at 2,200 to 5,000 m / min, followed by stretching and heat setting. It provides a method for producing a stretchable composite fiber.

In addition, the present invention (A) one polymer is polyethylene terephthalate number average molecular weight of 10,000 to 20,000 molecular weight distribution index of 1.5 to 2.5, another polymer is polyethylene terephthalate, polybutylene terephthalate or Melting two kinds of polyester having a number average molecular weight of 15,000 to 90,000 molecular weight distribution index of 1.5 to 2.5 with a polyethylene terephthalate copolymer, (B) Spinning pack such that the melt has a residence time in the spinning pack of 5 minutes or less After passing through, the spinning speed is 2,200 ~ 5,000m / min, drawn into side-by-side or sheath-core type composite yarn, followed by drawing and heat setting. It provides a method for producing a composite fiber produced by the method comprising the step.

In addition, the method for producing a stretchable composite fiber of the present invention is preferably produced by a partial orientation-stretching / flamming method or a radial direct stretching method.

Moreover, it is preferable that the said extending | stretching temperature is 85-95 degreeC, and the heat setting temperature is 160-220 degreeC.

The present invention also provides a processed yarn made of the stretchable composite fiber and having a twist number (TM: Twist / meter) of 150 to 2,000.

In addition, the present invention provides a blended yarn in which yarns of high shrinkage characteristics of the stretchable composite fiber and elongation of 50% or more and non-shrinkage of 15% or more are mixed.

The present invention also provides a fabric containing the stretchable composite fiber.

In order to produce a composite fiber having elasticity for minimizing the morphology of iron, different fiber-forming polymers having a difference in number average molecular weight of 5,000 to 70,000 and a molecular weight distribution index of 1.5 to 2.5 are preferred. The characteristics of, the method of analysis, and the method of preparation are described as follows.

1. Characteristics and analysis methods of different fiber-forming polymers having a difference in number average molecular weights of 5,000 to 70,000 and respective molecular weight distribution indices of 1.5 to 2.5

The two polymers used in the present invention have a number average molecular weight of 10,000 to 20,000 and a molecular weight distribution index of 1.5 in order to achieve a difference in number average molecular weight of 5,000 to 70,000 and a molecular weight distribution index of 1.5 to 2.5. The number average molecular weight of the other component should be 15,000 to 90,000 and the molecular weight distribution index should be 1.5 to 2.5.

The polymer to be used can be used industrially used polymers such as polyester and nylon, and modified polymers thereof. Other polymers such as polyurethane and polyacrylonitrile may also be used, but these may be decomposed in a high temperature process, and thus practical application is difficult. Polymers such as polyester or nylon and modified polymers thereof can be used, and specific examples thereof include polyester and isophthalic acid represented by polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, and the like. Copolymers thereof modified with polyethylene glycol and the like, and copolymers thereof modified with nylon and m-xylene diamine represented by nylon 6, nylon 66, nylon 46, etc. And polymers capable of melt molding.

Using these polymers, the number average molecular weight of one polymer should be 10,000-20,000, the molecular weight distribution index should be 1.5-2.5, and the number-average molecular weight of the other polymer should be 15,000-90,000 and the molecular weight distribution index should be 1.5-2.5. This means that the polymer of one component and the other component is not determined, but if the number average molecular weight of one polymer is 10,000 to 20,000 and the molecular weight distribution index is 1.5 to 2.5, the number average molecular weight of the other polymer is 15,000 to 90,000. And a molecular weight distribution index should be 1.5-2.5. More specifically, for example, if a polymer 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 a polyethylene terephthalate, the polymer having a number average molecular weight of 15,000 to 90,000 and a molecular weight distribution index of 1.5 to 2.5 is a polytree. Methylene terephthalate, polybutylene terephthalate, nylon 6 may be sufficient, and the same polyethylene terephthalate may mean. That is, as long as the difference in the number average molecular weight and the molecular weight distribution index by the gel permeation chromatography method are within the range defined by the present invention, it means that the types of polymers are the same, different or irrelevant. Therefore, in the present invention, a polymer 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 referred to as a low molecular weight polymer, and a polymer having a number average molecular weight of 15,000 to 90,000 and a molecular weight distribution index of 1.5 to 2.5 is called a high molecular weight polymer. .

These polymers are generally manufactured by known bulk polymerization, solution polymerization, interfacial polymerization, etc. The polymers of the present invention can be used by any method, and particularly preferably by melt polymerization in the bulk polymerization method. Polymers produced by solid phase polymerization are advantageous in terms of their production cost.

In the present invention, the low value of the molecular weight of the low molecular weight polymer is 10,000, and the high value of the molecular weight of the high molecular weight polymer is 90,000. It is not difficult to prepare a polymer having a molecular weight of less than 10,000 by the polymerization method itself. However, in order to fiberize using this polymer, it is advantageous to have a chip (chip or pellet). When the molecular weight is less than 10,000, the chip is too brittle when manufactured into chips, making it difficult to manufacture a chip having a uniform shape and having a molecular weight of 90,000. If it is exceeded, it is difficult to manufacture by melt polymerization method or solid state polymerization method, and even if it is possible, the time is too long and economically disadvantageous, and because the spinning temperature must be excessively increased, it is difficult to see the effect by molecular weight reduction by pyrolysis.

In addition, limiting the molecular weight distribution index to 1.5 to 2.5 means that if the molecular weight distribution index is smaller than 1.5, the molecular weight distribution becomes too uniform, and thus the role of low-molecular-weight material is insufficient for self-plasticizing, which leads to easy process problems. When the molecular weight distribution is greater than 2.5, the molecular weight distribution is increased, and the effect of mixing various polymers is expressed. When the heat setting temperature is raised above a certain level, plasticization occurs at the hot plate, ultimately, the maximum heat shrinkage stress is achieved. It is difficult to increase the temperature, and there is a problem of deterioration in shape stability and elasticity.

In the present invention, the number average molecular weight and the molecular weight distribution index are dissolved in hexafluoroisopropylalcohol (HFIP) in a polymer or a composite fiber prepared using polystyrene using a high temperature GPC set of Waters, Inc., USA. As a substance, the number average molecular weight (Mn) and the weight average molecular weight (Mw) were measured, and the molecular weight distribution index (Polydispersity Index, PDI) was converted from the following equation.

2. Preparation of Composite Fiber

The spinning temperature of the polymer during melt spinning to prepare the composite fiber was selected to be 20 to 70 ° C. higher than the melting temperature of each polymer. When the polymer spinning temperature is lower than 20 ° C below the melting temperature of the polymer, it becomes a non-uniform melting, the pressure in the extruder is too high, the workability is lowered, and the resulting composite fibers are nonuniform in physical properties. In addition, when the polymerization temperature is higher than 70 ° C, the flowability of the polymer is improved, but problems such as thermal decomposition of the polymer occur.

Each discharged fibrous polymer is bonded directly underneath the spinneret to give a composite fiber of side-by-side cross-section, or the eccentric sheath, which polymerizes as it enters the spinneret through the distribution plate. Core) It is possible to manufacture fiber of cross section.

In addition, in the case of a polymer having a high molecular weight, the molecular weight decrease due to inter-spinning pyrolysis is increased, and the molecular weight distribution is also widened, thereby minimizing the residence time of the polymer melt in the spin pack to 5 minutes or less, thereby exhibiting the properties and functional expression according to the above characteristics. I found that it can be maximized.

The obtained composite fiber can be made into fibers by a partial orientation-stretching / flamming method or a radial direct stretching method used for producing a conventional polyester composite fiber.

The present invention is a key technical component of the spinning speed is 2,200 ~ 5,000m / min. This is not only economically disadvantageous due to the reduction of polymer melt discharged by low-speed spinning when spinning at 2,200m / min or less, and ultimately the shrinkage rate of iron is more than 3% due to the increase of thermal shrinkage due to the improvement of draw ratio during stretching. Morphological stability against heat drops sharply. In general, fibers with crystals formed by high magnification at low spinning speeds exhibit high shrinkage with respect to heat. In addition, when spinning more than 5,000m / min, the stability of the spinning process is lowered due to the radioactive degradation due to the very different thermal and physical properties between the two different molecular weight polymers.

The present invention is another key technical component, which is characterized by a drawing temperature of 85-95 ° C. and a heat setting temperature of 160-220 ° C. when manufactured by partial orientation-drawing / flamming or radial direct drawing. . In the case of the stretching temperature, uniform stretching is difficult at 85 ° C. or lower, and the degree of plasticization by heat is high at 95 ° C. or higher, resulting in unstable inter-process fairness and its physical properties. When the heat setting temperature is less than 160 ℃, the maximum heat shrinkage stress temperature is less than 155 ℃, and high shrinkage occurs in the iron of the final processing bag, resulting in uneven shape stability of the product. In this case, the plasticization becomes severe and the fairness and physical properties are weakened.

In the case of the conventional composite fiber with crimps, the shrinkage of the fabric is usually 10% or more during post-processing, and even after final processing, more than 3% form deformation occurs in the iron, which makes it difficult to set the conditions during processing. There is a problem that it is difficult to stabilize the dimensions of the sewing product. Common textile products are usually subjected to thermal history of 130 ~ 190 ℃ and tension of 1 ~ 2g / d during weaving / dyeing, thermal setting, and iron. The present inventors found that the maximum temperature was closely related to each other, and when the maximum heat shrinkage stress temperature was improved to 155 ° C. or higher, the morphological stability of the product was found to be excellent.

 Table 1 shows the physical properties and the functionality of the fiber according to the conditions of the present invention.

Hereinafter, the structure and effect of the present invention will be described in more detail with specific examples and comparative examples, but these examples are only intended to more clearly understand the present invention, and are not intended to limit the scope of the present invention.

EXAMPLE

Evaluation criteria and measuring methods of the physical properties of the conjugated composite fiber produced by the method according to the present invention will be described first.

1. Heat shrinkage stress measurement

The initial load of 0.5g / d, the temperature increase rate of 2.2 ℃ / second was measured using a thermal stress tester of Kanebo.

2. Measurement of number average molecular weight and molecular weight distribution

The polymer or the prepared composite fiber was dissolved in hexafluoroisopropylalcohol (HFIP), and a number average molecular weight (Number avergae molecular weight) was determined using polystyrene as a reference material using a high temperature GPC set of Waters Corporation of the United States. , Mn) and the weight average molecular weight (Mw) were measured, and the molecular weight distribution index (PDI) was converted from Equation 1 below.

[Equation 1]

3. Measurement of crimp elongation and elastic recovery

In order to measure the crimp elongation and elastic recovery rate of the properties of the crimp-forming composite fiber prepared in the following examples were carried out as follows.

The fiber skein was immersed in boiling water for 30 minutes under no load, and then dried at room temperature, subjected to 0.1 g / d load for 2 minutes, and left for 10 minutes. After leaving the sample subjected to the above step for 2 minutes under a 0.002 g / d load, the length (L ₁ ) at that time was measured. 0.1 g / d load was added to the sample and the length (L ₂ ) was measured after 2 minutes. Furthermore, after removing the 0.1 g / d load, the length (L ₃ ) at that time was measured after 2 minutes. Crimping rate or elastic recovery rate was calculated by the following formula (2) or (3).

[Formula 2]

Crimping rate (%) = [(L ₂ -L ₁ ) / L ₂ ] × 100

[Equation 3]

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

4. Determination of iron shrinkage : Knitted and processed in the usual way and measured according to KS K 0558-2001, A-1 (dry heat iron method).

5. Crimp Size Measurement

Randomly sample 20 fibers and measure them with a self-weight optical microscope, and then measure the average of the crimp diameters.

Example 1.

In the preparation of crimp-forming composite fibers, polyethylene terephthalate having a number average molecular weight (Mn) of 12,632, molecular weight distribution index (PDI) 2.2, polytrimethylene tere having a number average molecular weight (Mn) of 19,149 and molecular weight distribution index (PDI) 2.4 Phthalate in a ratio of 5: 5 by weight using a conventional melt-combining spinning equipment in a eccentric sheath-core cross section of Fig. 2- (d), spinning temperature of 270 ° C, spinning speed of 2,200m / min, staying in the pack A polyester composite fiber was prepared such that the single yarn fineness was 3.4 denier by setting the time to 4 minutes. The composite fiber obtained by spinning / winding was stretched using a separate stretching device to prepare a crimp expression type elastic composite fiber having a single yarn fineness of 2.1 denier. At the time of stretching, the stretching ratio was 1.75 and the stretching temperature was 85 ° C. and the heat setting temperature was 160 ° C. The results are shown in Table 1, which showed very good elastic properties and form stability in yarn and fabric.

Example 2.

In the preparation of crimp-forming composite fibers, polyethylene terephthalate having a number average molecular weight (Mn) of 15,385, a molecular weight distribution index (PDI) 2.1 and a polytrimethylene tere having a number average molecular weight (Mn) of 33,522, a molecular weight distribution index (PDI) 2.1. Phthalate in a ratio of 5: 5 by weight to a side-by-side cross section of Fig. 2- (a) using a conventional melt-compositing equipment, spinning temperature 275 ° C, spinning speed 2,600m / min, Pack A polyester composite fiber was prepared such that the single yarn fineness was 3.4 denier by setting the residence time in 4 minutes. The composite fiber obtained by spinning / winding was stretched using a separate stretching device to prepare a crimp expression type elastic composite fiber having a single yarn fineness of 2.1 denier. At the time of stretching, the stretching ratio was 1.70, the stretching temperature was 90 ° C., the heat setting temperature was 180 ° C., and the results are shown in Table 1, which showed very good stretch properties and form stability in yarn and fabric.

Example 3.

In the preparation of crimp-forming composite fibers, polyethylene terephthalate having a number average molecular weight (Mn) of 18,211 and a molecular weight distribution index (PDI) 2.1, polytrimethylene tere having a number average molecular weight (Mn) of 88,245 and a molecular weight distribution index (PDI) 1.6. Phthalate in a ratio of 5: 5 by weight to a side-by-side cross section of Fig. 2- (a) using a conventional melt-compositing equipment, spinning temperature 285 ° C, spinning speed 3,800m / min, Pack A polyester composite fiber was prepared such that the single yarn fineness was 3.4 denier by the radial direct drawing method by setting the residence time to 4 minutes. A single yarn fineness crimp-expressing stretchable composite fiber of 2.1 denier grades prepared by spinning and winding to give a spring-shaped crimp was prepared. Elongation ratio at the time of radial direct stretching is carried out at 3.7, stretching temperature 90 ℃ heat setting temperature 170 ℃, the results are shown in Table 1, showing excellent stretch properties and shape stability in yarn and fabric.

Example 4.

In the preparation of crimp-forming composite fibers, polyethylene terephthalate having a number average molecular weight (Mn) of 12,632, molecular weight distribution index (PDI) 2.2, polyethylene terephthalate having a number average molecular weight (Mn) of 25,984 and molecular weight distribution index (PDI) 2.2 Spinning temperature 285 ° C., spinning speed 2,600 m / min, stay in the pack in the side-by-side cross section of FIG. 2- (a) using a conventional melt compounding equipment at a ratio of 5: 5 by weight. By setting the time to 4 minutes to prepare a polyester composite fiber so that the single yarn fineness is 4.6 denier. The composite fiber obtained by spinning / winding was stretched using a separate stretching device to prepare a crimp expression type stretchable composite fiber having a single yarn fineness of 2.8 denier, which is provided with a spring-shaped crimp. At the time of stretching, the stretching ratio was 1.70, the stretching temperature was 90 ° C., the heat setting temperature was 160 ° C., and the results are shown in Table 1, which showed very good stretching properties and shape stability in yarn and fabric.

Example 5.

In the preparation of crimp-forming composite fibers, polyethylene terephthalate having a number average molecular weight (Mn) of 13,691, molecular weight distribution index (PDI) 2.2, polyethylene terephthalate having a number average molecular weight (Mn) of 25,984 and molecular weight distribution index (PDI) 2.2 Emission temperature 285 ° C, spinning speed 2,600m / min, residence time in a pack with a eccentric sheath-core cross section of FIG. A polyester composite fiber was prepared such that the fine yarn fineness was set to 6.9 denier by setting it to minutes. The yarn obtained by spinning / winding was stretched using a separate stretching device to prepare crimp-expressing stretchable composite fibers having a single yarn fineness of 4.2 denier. At the time of stretching, the stretching ratio was 1.70, the stretching temperature was 90 ° C., the heat setting temperature was 160 ° C., and the results are shown in Table 1, which showed very good stretching properties and shape stability in yarn and fabric.

Example 6.

In the preparation of crimp-forming composite fibers, polyethylene terephthalate having a number average molecular weight (Mn) of 15,385, molecular weight distribution index (PDI) 2.2, polyethylene terephthalate having a number average molecular weight (Mn) of 31,300 and a molecular weight distribution index (PDI) 2.1 was prepared. Radiation temperature 295 ° C., spinning speed 2,400 m / min, stay in the pack in the side-by-side cross section of FIG. 2- (b) using a conventional melt composite spinning equipment at a ratio of 6: 4 by weight. A polyester composite fiber was prepared such that the single yarn fineness was 3.4 denier by setting the time to 4 minutes. The composite fiber obtained by spinning / winding was stretched using a separate stretching device to prepare a crimp expression type elastic composite fiber having a single yarn fineness of 2.1 denier. At the time of stretching, the stretching ratio was 1.62 and the stretching temperature was 90 ° C., the heat setting temperature was 220 ° C., and the results are shown in Table 1, which showed very good stretching properties and shape stability in yarn and fabric.

Example 7.

In the preparation of crimp-forming composite fibers, polyethylene terephthalate having a number average molecular weight (Mn) of 15,385, molecular weight distribution index (PDI) 2.2, isophthalic acid having a number average molecular weight (Mn) of 23,300 and molecular weight distribution index (PDI) 2.2 is 10. The polyethylene terephthalate substituted by mole% was spun at a side temperature of 275 ° C. in the side-by-side cross section of FIG. A polyester composite fiber was prepared such that the single yarn fineness was 3.4 denier by setting the speed of 2,900 m / min and the residence time in the pack of 4 minutes. The composite fiber obtained by spinning / winding was stretched using a separate stretching device to prepare a crimp expression type elastic composite fiber having a single yarn fineness of 2.1 denier. At the time of stretching, the stretching ratio is 1.67, the stretching temperature is 90 ℃ heat setting temperature 180 ℃, the results are shown in Table 1, it showed very excellent stretch properties and shape stability in the yarn and fabric.

Example 8.

In the preparation of crimp-forming composite fibers, polyethylene terephthalate having a number average molecular weight (Mn) of 15,385, a molecular weight distribution index (PDI) 2.2, and a polybutylene talate having a number average molecular weight (Mn) of 33,691 and a molecular weight distribution index (PDI) 2.2 In a side-by-side cross section of Fig. 2- (a) using a conventional melt compounding equipment at a ratio of 5: 5 by weight ratio, spinning temperature of 275 ° C, spinning speed of 2,400m / min, in the pack A polyester composite fiber was prepared such that the single yarn fineness was 3.4 denier by setting the residence time to 4 minutes. The composite fiber obtained by spinning / winding was stretched using a separate stretching device to prepare a crimp expression type elastic composite fiber having a single yarn fineness of 2.1 denier. At the time of stretching, the stretching ratio is 1.67, the stretching temperature is 90 ℃ heat setting temperature 180 ℃, the results are shown in Table 1, it showed very excellent stretch properties and shape stability in the yarn and fabric.

Comparative Example 1.

In the preparation of crimp-forming composite fibers, polyethylene terephthalate having a number average molecular weight (Mn) of 12,632, molecular weight distribution index (PDI) 2.2, polytrimethylene tere having a number average molecular weight (Mn) of 16,950 and molecular weight distribution index (PDI) 2.4 Phthalate in a ratio of 5: 5 by weight to a side-by-side cross section of Fig. 2- (a) using a conventional melt-combining spinning equipment with a spinning temperature of 270 ° C. and a spinning speed of 2,500 m / min. , Polyester composite fiber was prepared so that the single yarn fineness was 3.4 denier by setting the residence time in the pack to 4 minutes. The composite fiber obtained by spinning / winding was stretched using a separate stretching device to prepare a crimp expression type elastic composite fiber having a single yarn fineness of 2.1 denier. At the time of stretching, the stretching ratio was 1.70, the stretching temperature was 75 ℃ heat setting temperature 145 ℃, and the results are shown in Table 1, the stretch characteristics in the yarn and fabric was very reduced and the shape stability was unstable.

Comparative Example 2.

In the preparation of crimp-forming composite fibers, a polyethylene terephthalate having a number average molecular weight (Mn) of 12,691, a molecular weight distribution index (PDI) of 2.2, a polytrimethylene tere having a number average molecular weight (Mn) of 24,411, and a molecular weight distribution index of 2.7 Phthalate in a ratio of 5: 5 by weight using a conventional melt-combining spinning equipment in a eccentric sheath-core cross section of Fig. 2- (d), spinning temperature 265 ° C, spinning speed 1,500m / min, stay in the pack A polyester composite fiber was prepared such that the single yarn fineness was 6.0 denier by setting the time to 8 minutes. The composite fiber obtained by spinning / winding was stretched using a separate stretching device to prepare a crimp expression type elastic composite fiber having a single yarn fineness of 2.1 denier. The stretching ratio at the time of stretching is 2.85, the stretching temperature 75 ℃ heat setting temperature 140 ℃ was carried out, the results are shown in Table 1, the stretch characteristics of the yarn and fabric slightly reduced and showed that the shape stability is unstable.

Comparative Example 3.

In preparing crimp-forming composite fibers, polyethylene terephthalate having a number average molecular weight (Mn) of 15,805, molecular weight distribution index (PDI) 2.6, polytrimethylene tere having a number average molecular weight (Mn) of 30,680, and molecular weight distribution index (PDI) 2.6 Phthalate in a ratio of 5: 5 by weight to a side-by-side cross section of Fig. 2- (a) using a conventional melt-combined spinning equipment with a spinning temperature of 270 ° C. and a spinning speed of 1,400 m / min. , Polyester composite fiber was prepared such that the single yarn fineness was 8.1 denier by setting the residence time in the pack to 8 minutes. The composite fiber obtained by spinning / winding was stretched using a separate stretching device to prepare a crimp expression type stretchable composite fiber having a single yarn fineness of 2.8 denier, which is provided with a spring-shaped crimp. The stretching ratio at the time of stretching is 2.90, the stretching temperature is 80 ℃ heat setting temperature 150 ℃, the results are shown in Table 1, the elastic properties of the yarn and fabric slightly reduced and showed that the shape stability is unstable.

Comparative Example 4.

In the preparation of crimp-forming composite fibers, polyethylene terephthalate having a number average molecular weight (Mn) of 15,385, a molecular weight distribution index (PDI) of 2.2, a polybutylene tere having a number average molecular weight (Mn) of 31,292, and a molecular weight distribution index (PDI) of 2.8. Phthalate in a ratio of 5: 5 by weight to a side-by-side cross section of Fig. 2- (a) using a conventional melt-combining spinning equipment with a spinning temperature of 275 ° C. and a spinning speed of 1,400 m / min. , Polyester composite fiber was prepared so that the single yarn fineness was 6.0 denier by setting the residence time in the pack to 8 minutes. The composite fiber obtained by spinning / winding was stretched using a separate stretching device to prepare a crimp expression type elastic composite fiber having a single yarn fineness of 2.1 denier. The stretching ratio at the time of stretching is 2.90, the stretching temperature of 75 ℃ heat setting temperature 145 ℃ was carried out, the results are shown in Table 1, the stretch characteristics in the yarn and fabric slightly reduced and showed the shape stability is unstable.

Comparative Example 5.

In the preparation of crimp-forming composite fibers, polytrimethylene terephthalate having a number average molecular weight (Mn) of 13,490, a molecular weight distribution index (PDI) of 2.2, nylon 6, a number average molecular weight (Mn) of 31,290, and a molecular weight distribution index (PDI) of 2.8. In the ratio of 5: 5 by weight ratio, the side-by-side cross-section of the side-by-side of Figure 2- (a) using a conventional melt-combined spinning equipment, spinning temperature of 270 ° C, spinning speed of 1,400m / min, A polyester composite fiber was prepared such that the single yarn fineness was 6.0 denier by setting the residence time in the pack to 8 minutes. The composite fiber obtained by spinning / winding was stretched using a separate stretching device to prepare a crimp expression type elastic composite fiber having a single yarn fineness of 2.1 denier. The stretching ratio at the time of stretching is 2.90, the stretching temperature of 75 ℃ heat setting temperature 145 ℃ was carried out, the results are shown in Table 1, the stretch characteristics in the yarn and fabric slightly reduced and showed the shape stability is unstable.

1) S / S: Side-By-Side, S / C: Heat-Core, 2) Iron Shrinkage Acceptance Criteria: ± 3.0% or less

The elastic composite fiber prepared according to the present invention has a high elasticity of 40% or more, an elastic recovery rate of 70% or more, and a maximum heat shrinkage stress temperature of 155 ° C or higher, so the iron shrinkage of the final fabric is less than 3%. As a result, it can be said that the stability of the product during the post-processing is very excellent. In addition, the composite fiber produced by the present invention minimizes molecular weight reduction, yarn properties and elasticity deterioration by reducing polymer residence time in the spinning pack between the yarns, and improves the maximum temperature of the heat shrinkage stress compared to the existing yarn, and the product during the post-processing. Its shape stability is excellent and its elongation and stretching characteristics of yarn are excellent, so it can be applied to various applications such as fabric, circular knitting, and warp knitting.

1 is a thermal shrinkage stress analysis of the crimp-forming composite fiber excellent in elasticity and shape stability during post-processing used in the present invention.

2- (a), (b), (c) and (d) are cross-sectional views of a crimp-forming composite fiber having excellent stretchability and shape stability during post-processing.

Claims (11)

The maximum heat shrinkage stress of fibers obtained using two melt-spun fiber-forming polymers is at least 155 ° C, the crimp elongation is at least 40% and the elastic recovery is at least 70% after unloaded non-water treatment. An elastic composite fiber having excellent morphological stability, characterized by being capable of producing a processed fabric having a shrinkage of 3% or less. The method of claim 1, One polymer is a polyethylene terephthalate with a number average molecular weight of 10,000 to 20,000, a molecular weight distribution index of 1.5 to 2.5, and another polymer is a polytrimethylene terephthalate with a number average molecular weight of 15,000 to 90,000, a molecular weight distribution index. Is 1.5 to 2.5, and the number average molecular weight difference of the two polymers is 5,000 to 70,000. The method of claim 1, One polymer is a polyethylene terephthalate with a number average molecular weight of 10,000 to 20,000, a molecular weight distribution index of 1.5 to 2.5, and another polymer is a polyethylene terephthalate, polybutylene terephthalate or polyethylene terephthalate copolymer. An elastic composite fiber having excellent morphological stability, characterized in that the average molecular weight is 15,000 to 90,000, the molecular weight distribution index is 1.5 to 2.5, and the number average molecular weight difference of the two polymers is 5,000 to 70,000. The method of claim 1, Elastic composite fiber with excellent shape stability in the form of side-by-side type or heath-core type in cross section The method of claim 1, Elastic composite fiber with excellent form stability with a crimp diameter of 8 mm or less (A) One polymer is a polyethylene terephthalate with a number average molecular weight of 10,000 to 20,000 molecular weight distribution index of 1.5 to 2.5, and another polymer is a polytrimethylene terephthalate with a number average molecular weight of 15,000 to 90,000 molecular weight distribution. Melting two polyesters with an index of 1.5 to 2.5 (B) the melt is passed through the spin pack so that the residence time in the spin pack is 5 minutes or less, and then the spin speed is 2,200 to 5,000 m / min. Step to take out with (Sheath-Core) type composite yarn       (C) A method for producing a stretchable composite fiber excellent in shape stability produced by the method comprising the step of stretching the drawn composite yarn to a temperature of 85 to 95 ℃ and heat-setting at a temperature of 160 to 220 ℃. (A) One polymer is a polyethylene terephthalate having a number average molecular weight of 10,000 to 20,000 molecular weight distribution index of 1.5 to 2.5, and another polymer is a polyethylene terephthalate, polybutylene terephthalate or polyethylene terephthalate copolymer. Melting two polyesters having a number average molecular weight of 15,000 to 90,000 and a molecular weight distribution index of 1.5 to 2.5 (B) the melt is passed through the spin pack so that the residence time in the spin pack is 5 minutes or less, and then the spin speed is 2,200 to 5,000 m / min. Step to take out with (Sheath-Core) type composite yarn       (C) A method for producing a stretchable composite fiber excellent in shape stability produced by the method comprising the step of stretching the drawn composite yarn to a temperature of 85 to 95 ℃ and heat-setting at a temperature of 160 to 220 ℃. The method according to claim 6 to 7, A method for producing a stretchable composite fiber having excellent shape stability, which is produced by a partially oriented-stretching / flamming method or a radial direct stretching method. Processed yarns made of the stretchable composite fiber of claim 1 and having a twist number (TM) of 150 to 2,000. The blended yarn of the elastic composite fiber of claim 1 mixed with a yarn of high shrinkage characteristics having an elongation of 50% or more and a non-shrinkage rate of 15% or more. A fabric comprising the elastic composite fiber of claim 1.