Polyester hollow fiber raw cotton, polyester hollow fiber spherical material, and method for manufacturing the same

Abstract

To provide polyester hollow fiber raw cotton which is light in weight and excellent in bulkiness, is soft and rich in feather-like texture, and is suitable for forming a polyester hollow fiber spherical material for a filling material of cushions, down jackets, and the like.SOLUTION: Polyester hollow fiber raw cotton comprises a polyester hollow fiber having a two-dimensional crimp shape and a polyester hollow fiber having a three-dimensional crimp shape, and has a single fiber fineness of 2.0 to 6.6 dtex, a hollowness of 15 to 35%, the number of crimps of 2 to 10 crimps / 25 mm, a crimp percentage of 10 to 20%, and a fiber length of 20 to 50 mm.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to polyester hollow fiber raw material, polyester hollow fiber spheres, and methods for producing them. [Background technology]

[0002] Conventionally, feathers and polyester staple fibers have been widely used as padding or cushioning materials for down jackets and sleeping bags.

[0003] The feathers generally used are those of waterfowl, which are known for their rich texture, light weight, excellent heat retention, ability to conform to the body, high bulk, and high recovery rate. However, when trying to obtain natural feathers, there is a problem that the supply is limited and that the supply fluctuates due to natural conditions and the effects of epidemics.

[0004] Furthermore, from the perspective of nature conservation, there are limits to capturing wild birds, and if one were to raise waterfowl to obtain feathers, it would be necessary to raise a large number of waterfowl, which would not only require a large amount of feed but would also raise issues such as water pollution due to the waterfowl's excrement and the outbreak and spread of infectious diseases.

[0005] Furthermore, in order to make feathers usable as stuffing, they must go through many processes, such as collecting, sorting, disinfecting, degreasing, and stuffing into futons. In addition, the process is complicated because the feathers tend to fly up, and as a result, the prices of products using feathers tend to be high.

[0006] Furthermore, when feathers are harvested, meat remains at the ends of the feathers, causing a rotten smell, so there are movements in Europe and other places to eliminate feathers from the perspective of animal welfare.

[0007] On the other hand, polyester staple fibers are inexpensive and have excellent bulkiness, and are easy to spin during fiber production and to process into products such as nonwoven fabrics. Therefore, a well-known method involves covering a fibrous web laminate, which is made by laminating polyester staple fibers by carding or the like to form a fibrous web, with a side fabric. However, this method has the drawback of being time-consuming to cover the layered fibrous web laminate with the side fabric.

[0008] To address these issues, padding made of highly elastic fiber spheres (fiber balls) that have excellent elasticity, compression resistance, and shape stability has been proposed (Patent Document 1).

[0009] Also, a cushioning material has been proposed in which a binder liquid is sprayed onto the surface of cotton balls and then molded, and the surfaces of the cotton balls are bonded to the surfaces of other cotton balls (Patent Document 2).

[0010] Furthermore, it has been proposed that the use of fibers with three-dimensional helical crimps can improve the formability of fiber spheres and produce fiber spheres with excellent bulkiness (Patent Documents 3, 4, 5, and 6).

[0011] Furthermore, Patent Documents 1 and 6 also propose making fiber spheres using composite fibers that are a mixture of multiple types of fibers, such as fine fibers and binder fibers, in order to form dense air layers and improve bulkiness. [Prior art documents] [Patent documents]

[0012] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-169846 [Patent Document 2] Japanese Patent Application Laid-Open No. 2003-169978 [Patent Document 3] Japanese Patent Application Laid-Open No. 2016-160564 [Patent Document 4] WO2016 / 121643 publication [Patent Document 5] Japanese Patent Application Publication No. 2-118150 [Patent Document 6] Japanese Patent Application Publication No. 2023-157431 Summary of the Invention [Problem to be solved by the invention]

[0013] However, in the proposal of Patent Document 1, the fiber material used is fiber spheres made of, for example, polyester fiber and binder fiber, and the binder fiber is thermally fused using hot air or the like during sphere formation. This causes the fibers to shrink during thermal formation, resulting in high-density fiber spheres, which results in poor softness and bulkiness of the spheres. Furthermore, the presence of thermally bonded portions results in poor softness of the spheres. In the proposal of Patent Document 2, a binder liquid is sprayed onto the cotton balls to form a mold, which causes the spheres to adhere to each other, resulting in problems such as poor processability into the final product, poor blowability, poor sphere flowability, and reduced bulkiness. The proposals of Patent Documents 3 to 6 have problems such as excessive entanglement of the fibers constituting the fiber spheres, resulting in a hard texture, and furthermore, the fibers are difficult to open during fiber sphere formation, making them difficult to process.

[0014] Furthermore, the methods proposed in Patent Documents 1 and 6 for producing fiber spheres using composite fibers that are a mixture of multiple types of fibers, such as fine fibers and binder fibers, have the following problems: mixing multiple types of fibers is time-consuming; and the fibers are difficult to open during the formation of the fiber spheres, making them difficult to process.

[0015] Therefore, an object of the present invention is to solve the above-mentioned problems in the prior art and to provide polyester hollow fiber and fiber spheres that are not only lightweight and have excellent bulkiness, but also soft and have a texture similar to that of feathers, and are suitable for forming polyester hollow fiber spheres for use as padding materials in cushions, down jackets, etc. [Means for solving the problem]

[0016] The present inventors have considered that the use of polyester hollow fiber raw cotton is suitable for obtaining fiber spheres that are both lightweight and bulky. Furthermore, they have focused on the relationship between the crimp morphology of the polyester hollow fiber raw cotton and the bulkiness of the obtained fiber spheres, and have conducted extensive research to obtain an appropriate crimp morphology. Furthermore, they have found that imparting both two-dimensional and three-dimensional crimp morphologies to polyester hollow fibers improves the openability during fiber sphere formation, and enables lightweight, bulky fiber spheres to be easily obtained, leading to the completion of the present invention.

[0017] That is, the present invention has been made to achieve the above-mentioned object, and provides polyester hollow fiber raw material including polyester hollow fibers having a two-dimensional crimped morphology and polyester hollow fibers having a three-dimensional crimped morphology, the polyester hollow fiber raw material having a single fiber fineness of 2.0 to 6.6 dtex, a hollowness of 15 to 35%, the number of crimps of 2 to 10 crimps / 25 mm, a crimping rate of 10 to 20%, and a fiber length of 20 to 50 mm, and polyester hollow fiber spheres obtained by opening and sphericizing the polyester hollow fiber raw material. In addition, the method for producing polyester hollow fiber raw cotton of the present invention involves spinning polyester from a hollow fiber spinneret, asymmetrically cooling the spun yarn by blowing cooling air from one side of the spun yarn, then taking it up, hot stretching it, imparting mechanical crimping, applying an oil agent containing polysiloxane, causing three-dimensional crimping by heat setting, and cutting it to a predetermined fiber length to produce polyester hollow fiber raw cotton, and the method for producing polyester hollow fiber spheres involves opening the polyester hollow fiber raw cotton obtained by the above-mentioned method for producing polyester hollow fiber raw cotton and making it into spheroids. [Effects of the Invention]

[0018] According to the present invention, polyester hollow fiber spheres can be obtained using polyester hollow fiber raw cotton, which is not only lightweight and has excellent bulkiness, but also soft and has a texture similar to that of feathers, and is suitable for use as a padding material for cushions, down jackets, etc. DETAILED DESCRIPTION OF THE INVENTION

[0019] Next, embodiments of the polyester hollow fiber raw fiber and fiber spheres of the present invention and their production methods will be specifically described.

[0020] The present invention relates to a polyester hollow fiber raw material, including hollow fibers having a two-dimensional crimped morphology and hollow fibers having a three-dimensional crimped morphology, characterized in that the hollow fibers have a single fiber fineness of 2.0 to 6.6 dtex, a hollow ratio of 15 to 35%, a number of crimps of 2 to 10 crimps / 25 mm, a crimp ratio of 10 to 20%, and a fiber length of 20 to 50 mm, and polyester hollow fiber spheres made thereof.

[0021] Examples of polyesters constituting the hollow fibers contained in the polyester hollow fiber raw cotton of the present invention include polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, polyethylene naphthalate, and polybutylene naphthalate, and they may contain copolymer components, but polyethylene terephthalate is preferably used.

[0022] The intrinsic viscosity of the polyester used in the present invention is preferably 0.60 to 0.75. The intrinsic viscosity is more preferably 0.62 to 0.72. If the intrinsic viscosity is less than 0.6, the ability to develop crimp decreases, resulting in low crimp, making it difficult for the fibers to curl into a spherical shape during processing into fiber spheres, making the formation of fiber spheres difficult. Furthermore, the rigidity of the fiber also decreases, making it difficult to obtain fiber spheres with sufficient bulkiness. On the other hand, if the intrinsic viscosity exceeds 0.75, the melt viscosity increases, making fiber production difficult.

[0023] It is important that the single fiber fineness of the polyester hollow fiber raw fiber of the present invention is 2.0 to 6.6 dtex. The single fiber fineness is preferably 2.2 to 4.4 dtex. If the positive single fiber fineness is less than 2.0 dtex, the positive single fiber fineness becomes too thin, resulting in a decrease in the ability to develop crimp and a decrease in crimp, making it difficult for the fibers to be rounded into a spherical shape during processing into fiber spheres, making it difficult to form fiber spheres. Furthermore, the rigidity of the fiber decreases, resulting in fiber spheres lacking bulkiness. On the other hand, if the single fiber fineness exceeds 6.6 dtex, the rigidity of the fiber when processed increases, making it impossible to obtain soft fiber spheres that are similar to feathers.

[0024] It is important that the hollow fiber contained in the polyester hollow fiber raw fiber of the present invention has a hollowness of 15 to 35%. The hollowness is more preferably 20 to 30%. If the hollowness is less than 15%, asymmetric cooling becomes insufficient, the ability to develop crimp decreases, and the crimp becomes low. This makes it difficult for the fibers to curl into a spherical shape during processing into fiber spheres, making it difficult to form fiber spheres. On the other hand, if the hollowness is more than 35%, there may be many thread breakages during spinning, making stable fiber production difficult.

[0025] The hollowness of the hollow fibers contained in this polyester hollow fiber raw fiber can be expressed as a percentage by calculating the ratio of the area of ​​the hollow portion to the total area of ​​the fiber cross section including the hollow portion using an enlarged photograph of the fiber cross section.

[0026] In the present invention, "hollow" means that the fiber has a cavity inside the outer shape of the fiber in cross section. The cavity is preferably located at the center of the fiber, but may be located eccentrically from the center of the fiber, but the cavity is preferably located at the center of the fiber.

[0027] The hollowness depends on the die design, the intrinsic viscosity of the polyester and the cooling conditions, and can be controlled by those skilled in the art through each specific setting.

[0028] It is important that the polyester hollow fiber raw cotton of the present invention contains hollow fibers having a two-dimensional crimped shape and hollow fibers having a three-dimensional crimped shape.

[0029] In the present invention, two-dimensional crimping refers to a mechanical crimping imparted by a crimper or the like, and refers to a planar continuous buckling structure, while three-dimensional crimping refers to a three-dimensional continuous buckling structure, such as a spiral crimping structure.

[0030] If the crimping form contained in the polyester hollow fiber raw cotton is only two-dimensional, the fibers are difficult to curl into a spherical shape during processing into fiber spheres, making it difficult to form fiber spheres. On the other hand, if the crimping form is only three-dimensional, the bulkiness of the obtained fiber spheres is improved due to the increase in three-dimensional voids, but on the other hand, the entanglement between the fibers becomes too strong, making it difficult to open the fiber spheres during processing.

[0031] It is important that the two-dimensional crimp ratio of the polyester hollow fiber raw cotton of the present invention is 10 to 75%, more preferably 10 to 50%, and it is important that the three-dimensional crimp ratio is 25 to 90%, more preferably 50 to 90%.

[0032] The two-dimensional crimp ratio and three-dimensional crimp ratio of this polyester hollow fiber raw cotton refer to the content ratio of fibers of each crimp type, and can be expressed in % by calculating the percentage based on the weight ratio when the polyester hollow fiber raw cotton is sorted according to the crimp type. As in the manufacturing method exemplified later, the polyester hollow fiber raw cotton of the present invention will contain a small amount of fibers having both two-dimensional and three-dimensional crimp types (hereinafter referred to as fibers having both crimp types), and fibers having both crimp types will be counted as fibers with a higher proportion of the crimp type in their fiber length to calculate the crimp ratio.

[0033] It is important that the crimp number of the hollow fibers contained in the polyester hollow fiber raw cotton of the present invention is 2 to 10 crimps / 25 mm. The crimp number is preferably 3 to 8 crimps / 25 mm. If the crimp number is less than 2 crimps / 25 mm, the fibers are less likely to curl into a spherical shape during processing into fiber spheres, making it difficult to form fiber spheres. On the other hand, if the crimp number exceeds 10 crimps / 25 mm, the fibers become too entangled, resulting in poor openability during processing into fiber spheres. Furthermore, the diameter of the obtained fiber spheres is small and their density is high, resulting in fiber spheres lacking bulkiness.

[0034] The crimp ratio of the hollow fibers contained in the polyester hollow fiber raw cotton of the present invention is preferably 10 to 20%. The crimp ratio is more preferably 12 to 18%. If the crimp ratio is less than 10%, the fibers are less likely to curl into a spherical shape during processing into fiber spheres, making it difficult to form fiber spheres. On the other hand, if the crimp ratio is more than 20%, the fibers become too entangled, resulting in poor openability during processing into fiber spheres. Furthermore, the diameter of the obtained fiber spheres becomes smaller and the density increases, resulting in fiber spheres lacking bulkiness.

[0035] The crimp number and crimp rate in the present invention are measured in accordance with JIS L1015 (2010), but the same number of fibers having two-dimensional crimp morphology and three-dimensional crimp morphology are selected and measured. In this case, fibers having both crimp morphology are preferably not included.

[0036] It is important that the fiber length of the hollow fibers contained in the polyester hollow fiber raw cotton of the present invention is 20 to 50 mm. The fiber length is preferably 25 to 40 mm. If the fiber length is less than 20 mm, the entanglement of the fibers during processing into fiber spheres becomes weak, and the entanglement is released, making it difficult to maintain the shape of the spheres. On the other hand, if the fiber length exceeds 50 mm, the fibers become difficult to curl into a spherical shape during processing into fiber spheres, making it difficult to form fiber spheres. Furthermore, the fiber spheres tend to entangle with each other, resulting in a lack of fluidity and a deterioration in product quality.

[0037] The polyester hollow fiber raw cotton of the present invention preferably has a polysiloxane-containing oil solution adhered to it in an amount (ratio) of 0.3 to 1.0 mass% relative to the mass of the raw cotton. The amount of oil solution adhered is more preferably 0.4 to 0.8 mass%. If the amount of polysiloxane-containing oil solution is less than 0.3 mass%, the smoothness of the fiber decreases and the fiber spheres tend to entangle with each other, which may result in a lack of flowability of the fiber spheres and a deterioration in product quality. On the other hand, even if the amount of oil solution adhered exceeds 1.0 mass%, no further improvement in fiber smoothness is observed and this may lead to a deterioration in the unit consumption.

[0038] The polysiloxane used in the present invention may be, for example, an amino-modified silicone. The polysiloxane can be applied to and adhered to the polyester hollow fiber by applying an oil containing the polysiloxane. In addition to the polysiloxane, the oil preferably contains a phosphoric acid compound, an aliphatic compound, and a halogen-based compound, and more preferably contains an antioxidant, a flame retardant, and an antistatic agent.

[0039] When applying the oil solution containing this polysiloxane, it is preferable to apply an aqueous oil solution having a polysiloxane concentration of preferably 3 to 10 mass %, more preferably 4 to 8 mass %, to the polyester hollow fiber, and then dry it at any temperature.

[0040] The fiber friction coefficient μs of the hollow fibers contained in the polyester hollow fiber raw cotton of the present invention is preferably 0.06 to 0.14. The fiber friction coefficient μs is more preferably 0.07 to 0.12. If the fiber friction coefficient μs is less than 0.07, the fiber smoothness decreases and the fiber spheres tend to entangle with each other, which may result in a lack of flowability of the fiber spheres and a deterioration in product quality. On the other hand, even if the fiber friction coefficient μs exceeds 0.12, no further improvement in fiber smoothness is observed.

[0041] The polyester hollow fiber spheres of the present invention are fiber spheres formed by opening and sphering the polyester hollow fiber raw cotton of the present invention, and their bulkiness is preferably 7,500 cm3 / 50 g or more, more preferably 8,000 cm3 / 50 g or more. If the bulkiness is less than 7,500 cm3 / 50 g, sufficient bulk cannot be obtained, and the resulting fiber spheres may be inferior in lightness and volume.

[0042] Next, the method for producing the polyester hollow fiber raw fiber and polyester hollow fiber spheres of the present invention will be described by taking one specific embodiment as an example.

[0043] First, polyester is melted and spun through a hollow fiber spinneret having preferably 90 to 400 hollow fiber outlet holes at a spinning temperature that is about 15 to 30°C higher than the melting point so as to form hollow sections. Immediately after spinning, air (cooling air) at a temperature of preferably 10 to 25°C is blown onto one side of the spun yarn at a flow rate of preferably 80 to 130 m / min to asymmetrically cool it, and then further cooled with air at a temperature of preferably 10 to 25°C at a flow rate of preferably 140 to 170 m / min, a spinning oil is applied, and the spun yarn is temporarily placed in a can at a take-up speed of preferably 1000 to 1700 m / min to obtain an undrawn yarn tow.

[0044] The undrawn yarn tow is then subjected to one-stage drawing, preferably at a draw ratio of 2.3 to 3.0 times, using a liquid bath at a temperature of 75 to 100°C, and mechanically crimped using a crimper. After that, an oil containing polysiloxane is applied, and three-dimensional crimping is caused by heat setting. After that, the polyester hollow fiber raw cotton can be produced by cutting to a predetermined fiber length.

[0045] In the mechanical crimping process using a crimper, it is necessary to adjust the width of the tow introduced into the stuffing box and the pressure inside the box so as to achieve the desired number of crimps, crimp rate, and two-dimensional crimp ratio.

[0046] In the method for forming polyester hollow fiber spheres of the present invention, the polyester hollow fiber raw cotton obtained as described above is thoroughly opened using a card or the like equipped with a plurality of rollers each having a garnet wire on its surface, and the thoroughly opened fibers are then spheronized (formed into spheroids) using an apparatus in which the thoroughly opened fibers are blown into a chamber equipped with a rotating body with a plurality of fins in a cylindrical space where air turbulence is likely to occur, and are then removed after a predetermined period of turbulent agitation, or the thoroughly opened fibers are retained in a fairly large chamber while creating an air vortex, and then spheronized. By receiving mechanical forces from the rigid body (fins) and air, the loop-shaped crimping further progresses, and fiber spheres can be formed.

[0047] The polyester hollow fiber spheres of the present invention preferably have an average diameter of 3 to 8 mm, more preferably 4 to 6 mm. Fiber spheres with an average diameter of less than 3 mm are difficult to process, while fiber spheres with an average diameter of more than 8 mm are not suitable for product processing, such as blowing.

[0048] The polyester hollow fiber spheres of the present invention are not only lightweight and have excellent bulkiness, but also soft and have a texture similar to that of feathers, and are therefore suitable for use as padding materials for cushions, down jackets, etc. [Example]

[0049] Next, the polyester hollow fiber raw material and polyester hollow fiber spheres of the present invention and their production method will be described in detail with reference to examples. The methods for measuring physical properties and the like are as follows.

[0050] (intrinsic viscosity) The sample was dissolved in orthochlorophenol, and the free-fall time was measured using an Ubbelohde viscometer. The intrinsic viscosity was calculated as an average value of N=3 relative to that of a standard sample.

[0051] (single fiber fineness, number of crimps, crimp rate, fiber length and fiber friction coefficient μs) Measurements were made in accordance with JIS L1015 (2010). The number of crimps and the crimp rate were measured by selecting the same number of fibers with two-dimensional crimping morphology and fibers with three-dimensional crimping morphology (fibers with both crimping morphology were not included).

[0052] (2D shrinkage ratio, 3D shrinkage ratio) An 80 g sample of the obtained polyester hollow fiber was visually inspected to separate fibers having two-dimensional crimping morphology and fibers having three-dimensional crimping morphology, and the weight proportion of fibers having each crimping morphology was calculated using the following formulas (1) and (2). Fibers having both crimping morphologies were counted as fibers having the crimping morphology with the highest proportion of their fiber length. Two-dimensional crimp ratio (%) = (weight of fiber having two-dimensional crimped shape) / sample amount 80 g × 100 ···(1) Three-dimensional crimp ratio (%) = (weight of fiber with three-dimensional crimped shape) / sample amount 80 g × 100 ···(2) (Amount of oil containing polysiloxane attached to fiber mass) The sample was decomposed with fuming sulfuric acid and fuming nitric acid, carbonized in an electric furnace, and then dissolved in alkali.The sample was then colored with ammonium molybdate, and the absorbance was measured with a spectrophotometer.The amount of inorganic silicone (Si) was calculated from the calibration curve, and the average value of N=3 was converted into the amount of oil.

[0053] (Hollow rate) The cross section of the obtained polyester hollow fiber raw cotton was photographed using a microscope at 400x magnification, and the cross section photograph was then enlarged and copied. The cross section of the fiber portion was cut out from the copied paper, and the mass was measured at N=20 on an electronic balance. Next, the hollow portion was cut out, and the mass was measured at N=20 on an electronic balance. The mass ratio was calculated from the arithmetic average using the following formula (3). Hollowness ratio (%) = (hollow part mass / fiber part cross-sectional mass) × 100...(3) (Processability of fiber spheres) The processability of the fiber spheres was evaluated as follows: (S) the polyester hollow fiber raw cotton has good openability and the formation of fiber spheres proceeds easily; (A) the polyester hollow fiber raw cotton has no problem in openability and the formation of fiber spheres is possible; (B) the polyester hollow fiber raw cotton has poor openability and the production efficiency of spheres is low; and (C) the polyester hollow fiber raw cotton is poor in openability and the production efficiency of spheres is very low and there is a lot of loss, although the formation of fiber spheres is possible.

[0054] (bulk of fiber spheres) A 50g±0.1g sample of the fiber sphere was weighed and placed in a measuring cylinder with an inner diameter of 28.8cm and a height of 50cm. A load of 94.3g was applied and the bulkiness was measured after 5 minutes. The measurement result was the average of 5 measurements and calculated using the following formula (4). Bulk=V=25πd 2 H / 2M (unit: cm 3 / 50g)···(4) (In the formula, d is the inner diameter of the measurement cylinder, d = 28.8 cm. H is the bulk (average value) of the sample, expressed in cm. M is the amount of the fiber sphere sample, expressed in g.) (diameter of fiber sphere) The diameters of randomly selected fiber spherules were measured with a vernier caliper, and the average value of N=100 was calculated.

[0055] (Texture / softness of fiber spheres) Ten panelists ranked the feel (texture; softness / softness) of the product when touched with their hands, from good to bad, on a scale of 10 to 0. The conventional fiber spheres described in Comparative Example 6 were used as the standard (9 points) for ranking, and an average score of more than 8 points was rated as very good texture (S), 6 points or more but less than 8 points was rated as good texture (A), 4 points or more but less than 6 points was rated as poor texture (B), and less than 4 points was rated as very poor texture (C).

[0056] [Example 1] Polyester hollow fiber raw cotton was produced by the following method: Polyethylene terephthalate (melting point 260°C) with an intrinsic viscosity of 0.650 was melted and melt-spun through a hollow spinneret with 300 nozzle holes at a spinning temperature of 280°C. Immediately after being spun from the spinneret, air at 20°C was blown onto one side of the spun yarn at a rate of 100 m / min to asymmetrically cool it, and then air at 20°C was blown onto the yarn at a rate of 160 m / min to cool it further. A spinning oil was applied, and the yarn was temporarily placed in a can at a take-up speed of 1500 m / min to obtain an undrawn yarn tow.

[0057] The undrawn yarn tow was then subjected to one-stage drawing at a draw ratio of 2.6 using a liquid bath at 80°C, followed by a mechanical crimping step using a crimper, whereupon an oil solution containing polysiloxane was applied, and the resultant fiber was heat-set at 165°C to induce three-dimensional crimping. The fiber was then cut to the specified fiber length shown in Table 1, thereby producing polyester hollow fibers having the properties shown in Table 1.

[0058] In the mechanical crimping process using a crimper, the width of the tow introduced into the stuffing box and the pressure inside the box were adjusted to achieve the desired number of crimps, crimp rate, and two-dimensional crimp ratio listed in Table 1.

[0059] The resulting polyester hollow fiber raw material was then thoroughly opened using a card equipped with multiple rollers with garnet wire on their surfaces. The fibers were then blown into a cylindrical chamber equipped with a rotating rotor with multiple fins, where turbulent air flow is likely to occur, and removed after a predetermined period of turbulent agitation to obtain polyester hollow fiber spheres. The resulting fiber structure was confirmed to be polyester hollow fiber spheres with excellent bulkiness and a soft texture. Regarding the processability of the fiber spheres, the polyester hollow fibers were easily opened and the formation of fiber spheres proceeded easily. The results are shown in Table 1.

[0060] [Example 2] Polyester hollow fiber raw material was produced under the same conditions as in Example 1, except that the mechanical crimping conditions in the crimper were adjusted so that the two-dimensional crimp ratio was 10% and the three-dimensional crimp ratio was 90%, and polyester hollow fiber spheres were obtained. The polyester hollow fibers constituting the obtained polyester hollow fiber spheres had slightly inferior openability due to the lower two-dimensional crimp ratio compared to Example 1, but there were no problems with processability, and polyester hollow fiber spheres were easily obtained. Furthermore, the increased three-dimensional crimp ratio compared to Example 1 meant that the obtained polyester hollow fiber spheres had excellent bulkiness. The results are shown in Table 1.

[0061] [Example 3] Polyester hollow fiber raw material was produced under the same conditions as in Example 1, except that the mechanical crimping conditions in the crimper were adjusted to a two-dimensional crimp ratio of 60% and a three-dimensional crimp ratio of 40%, and polyester hollow fiber spheres were obtained. The polyester hollow fiber raw material constituting the obtained polyester hollow fiber spheres had a higher two-dimensional crimp ratio than in Example 1, resulting in superior openability, while the lower three-dimensional crimp ratio reduced the entanglement of the fibers, slightly reducing processability into fiber spheres. However, processing was possible without problems, and polyester hollow fiber spheres were easily obtained. Furthermore, the bulkiness of the obtained polyester hollow fiber spheres was slightly reduced due to the lower three-dimensional crimp ratio compared to Example 1, but they still had excellent bulkiness. The results are shown in Table 1.

[0062] [Comparative Example 1] Polyester hollow fiber raw fiber was produced under the same conditions as in Example 1, except that the spinneret dimensions and output rate were adjusted to obtain a polyester hollow fiber raw fiber with a single fiber fineness of 1.2 dtex, and polyester hollow fiber spheres were obtained. The polyester hollow fiber raw fiber that constituted the obtained polyester hollow fiber spheres had a thinner single fiber fineness, which reduced the ability to develop crimp and reduced crimp, resulting in a low crimp ratio. This made it difficult for the fibers to curl into a spherical shape during processing into fiber spheres, and polyester hollow fiber spheres could not be formed. The results are shown in Table 1.

[0063] Comparative Example 2 Polyester hollow fiber raw fiber was produced under the same conditions as in Example 1, except that the spinneret dimensions and output rate were adjusted to obtain a polyester hollow fiber raw fiber with a single fiber fineness of 7.0 dtex, and polyester hollow fiber spheres were obtained. The polyester hollow fiber raw fiber constituting the obtained polyester hollow fiber spheres had a large single fiber fineness and high fiber rigidity, resulting in fiber spheres with poor texture and lacking softness. The results are shown in Table 1.

[0064] Comparative Example 3 Polyester hollow fiber raw fiber was produced under the same conditions as in Example 1, except that the spinneret dimensions and the wind speed during spinning and cooling were adjusted to obtain a polyester hollow fiber raw fiber with a hollow ratio of 10%, and polyester hollow fiber spheres were obtained. The polyester hollow fiber raw fiber constituting the obtained polyester hollow fiber spheres had a low hollow ratio and poor bulkiness. The results are shown in Table 1.

[0065] Comparative Example 4 Polyester hollow fiber raw cotton was produced under the same conditions as in Example 1, except that the polyester hollow fiber raw cotton had a fiber length of 64 mm, and polyester hollow fiber spheres were obtained. Because the polyester hollow fiber raw cotton constituting the obtained polyester hollow fiber spheres had a long fiber length, the fibers were difficult to curl into a spherical shape during processing into fiber spheres, and as a result, poorly shaped fiber spheres and entangled fiber spheres were observed. The results are shown in Table 1.

[0066] Comparative Example 5 Polyester hollow fibers were produced under the same conditions as in Example 1, except that the spinneret dimensions and the extrusion rate were adjusted to a single fiber fineness of 6.6 dtex, the number of crimps was 10.0 crimps / 25 mm, the crimp rate was 18.5%, and the fiber length was 50 mm.

[0067] Additionally, composite sheath-core staple fibers with a core component of polybutylene terephthalate (melting point 225°C) and a sheath component of a block copolymer polyether polyester elastomer with a melting point of 160°C (50 / 50 core / sheath weight ratio) were stretched 2.0 times, then coated with an oil containing polysiloxane, dried at 120°C to induce crimping, and cut to 38 mm. The resulting composite staple fibers had a fineness of 3.3 dtex, a crimp count of 9.5 crimps / 25 mm, and a crimp percentage of 16.0%.

[0068] The resulting mixture was passed through a roller card twice to achieve a blend ratio of 90% polyester hollow fiber and 10% composite staple fiber, yielding a bulky blend. The resulting mixture was placed in a device connecting a blower and a cotton storage box with a duct, and agitated with air for 30 seconds to form fiber spherules. The mixture was then transferred to another cotton storage box and agitated with a weak airflow at 195°C to melt the thermoplastic elastomer component and form flexible thermally bonded points within the fiber spherules. Room-temperature air was then blown in, and the resulting fiber spherules were cooled to form.

[0069] Heating the low-melting thermoplastic elastic elastomer to heat bond it increased the density, resulting in low bulkiness and poor softness of the resulting polyester hollow fiber spheres. The results are shown in Table 1.

[0070] Comparative Example 6 Polyester hollow fiber raw cotton was produced under the same conditions as in Example 1, except that the mechanical crimping step using a crimper was omitted and the two-dimensional crimp ratio was adjusted to 0% and the three-dimensional crimp ratio to 100%, and polyester hollow fiber spheres were obtained. The polyester hollow fiber raw cotton constituting the obtained polyester hollow fiber spheres had excellent bulkiness due to an increased three-dimensional crimp ratio compared to Example 1, but the two-dimensional crimp ratio was decreased, resulting in poor openability, very poor sphere production efficiency, and high waste. The results are shown in Table 1.

[0071] Comparative Example 7 Polyester hollow fiber raw cotton was produced under the same conditions as in Example 1, and polyester hollow fiber spheres were obtained, except that the mechanical crimping conditions in the crimper were adjusted so that the two-dimensional crimp ratio was 5% and the three-dimensional crimp ratio was 95%. The polyester hollow fiber raw cotton constituting the obtained polyester hollow fiber spheres had excellent bulkiness due to an increased three-dimensional crimp ratio compared to Example 1, but the two-dimensional crimp ratio was decreased, resulting in poor openability and poor sphere production efficiency. The results are shown in Table 1.

[0072] [Comparative Example 8] Polyester hollow fiber raw material was produced under the same conditions as in Example 1, and polyester hollow fiber spheres were obtained, except that the spinneret dimensions and output rate were adjusted to a single fiber fineness of 2.2 dtex, and the mechanical crimping conditions in the crimper were adjusted to achieve a crimp count of 13.0 crimps / 25 mm, a crimp rate of 20.5%, a two-dimensional crimp ratio of 25%, and a three-dimensional crimp ratio of 75%. The polyester hollow fiber raw material constituting the obtained polyester hollow fiber spheres had excessively strong entanglement between the fibers, which resulted in poor openability during processing into fiber spheres and poor bulkiness. The results are shown in Table 1.

[0073] [Table 1]

Claims

1. The polyester hollow fiber raw cotton includes polyester hollow fibers having a two-dimensional crimped form and polyester hollow fibers having a three-dimensional crimped form, and has a single fiber fineness of 2.0 to 6.6 dtex, a hollow ratio of 15 to 35%, a number of crimps of 2 to 10 crimps / 25 mm, a crimp ratio of 10 to 20%, and a fiber length of 20 to 50 mm.

2. 2. Polyester hollow fiber spheres obtained by opening and sphering the polyester hollow fiber raw fiber according to claim 1.

3. A method for producing the polyester hollow fiber raw cotton described in claim 1, characterized in that polyester is spun from a hollow fiber spinneret, cooled asymmetrically by blowing cooling air from one side of the spun yarn, then taken up, hot-stretched, and given mechanical crimp, and then an oil agent containing polysiloxane is applied, three-dimensional crimping is caused by heat setting, and the yarn is cut to a predetermined fiber length to produce polyester hollow fiber raw cotton.

4. 3. The method for producing polyester hollow fiber spheres according to claim 2, comprising the steps of: spinning polyester through a hollow fiber spinneret; asymmetrically cooling the spun yarn by blowing cooling air from one side of the spun yarn; taking it up; hot stretching the spun yarn to impart mechanical crimp; applying an oil containing polysiloxane; developing three-dimensional crimping by heat setting; and cutting the spun yarn to a predetermined fiber length to obtain polyester hollow fiber raw filaments; and then opening and spheronizing the obtained polyester hollow fiber raw filaments.

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