JP2013036130A - Polyester conjugate fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyester conjugate fiber that is good in spinnability and processability and has excellent thermal insulation properties especially when made into a fabric.SOLUTION: The polyester conjugate fiber includes: a polymer (A) including a polyester-based resin; and a polymer (B) including a polyester-based resin containing 1-20 mass% of silica having an average secondary particle diameter of 0.05-3.0 μm and including particles having a secondary particle diameter of 5 μm or more at a ratio of 10 vol.% or less, and the polymer (A) covers the polymer (B). The conjugate fiber is divided into 4 to 30 pieces in a cross section of the fiber. The mass ratio (A/B) of the polymer (A) to the polymer (B) is 60/40-20/80.

Description

  The present invention relates to a polyester composite fiber having good yarn-making properties and processability, and particularly to a polyester composite fiber having excellent heat retention when made into a fabric.

  2. Description of the Related Art Conventionally, it is known to use a three-layered structure using batting for sports clothing such as winter clothing, skiing, and mountain climbing. Such garments are generally composed of three layers consisting of a surface layer, batting, and lining, and the batting becomes an air heat retaining layer to enhance the heat retaining performance, but the garments composed of the three layer structure are heavy and sporty. There was a drawback that it was hung.

  In addition, there are known heat-insulating fabrics using fabrics coated with metals such as aluminum and chromium. However, when these fabrics are used in clothing, they lack flexibility due to coating, or have a heat-retaining performance when used repeatedly. There was a drawback of lowering.

  In order to eliminate the above-mentioned drawbacks, a core-sheath composite yarn is known in which functional inorganic particles having an infrared absorption effect such as zirconium carbide, zirconium silicide, tin oxide, etc. are arranged on the core and the sheath is covered with a thermoplastic resin. (For example, refer to Patent Document 1). In these core-sheath composite yarns, the functional inorganic particles arranged in the core part absorbs infrared rays to exhibit a heat retaining effect. However, these core-sheath composite yarns show a heat retaining effect in the presence of sunlight, but there is a problem that a sufficient heat retaining effect cannot be obtained in an environment where sunlight cannot be obtained such as indoors or at night.

  Polyester fibers containing silica are also known, but the primary average particle diameter before dispersion of the silica used is as wide as 0.01 to 10 μm, and the silica is stirred and dispersed during polymerization of the polyester resin. Thus, there was a problem that silica was agglomerated at the time of spinning and the spinning property was poor (for example, see Patent Document 2).

Japanese Patent Laid-Open No. 5-009804 JP 2002-309444 A

  An object of the present invention is to provide a polyester composite fiber having good yarn-making properties and processability, and particularly to provide a polyester composite fiber having excellent heat retention when made into a fabric.

In the Japanese Patent Application No. 2011-051630, the present inventors have already used a specific silica and used a silica-containing polyester resin that has passed a specific polymerization condition as a polymer constituting the core, thereby agglomerating silica during spinning. It has been clarified that a polyester core-sheath composite yarn having very little heat retention can be obtained with good operability, but as a result of intensive studies to further improve heat retention, a specific divided cross-sectional structure is obtained. It has been found that, by having preferably a specific hollowness, remarkable heat retention is exhibited, and the present invention has been achieved.
That is, the gist of the present invention is the following (1) to (2).
(1) A polymer (A) comprising a polyester resin and silica having a secondary average particle diameter of 0.05 to 3.0 μm and a ratio of secondary particle diameter of 5 μm or more of 10% by volume or less. A composite fiber comprising a polymer (B) made of a polyester-based resin containing a mass%, wherein the polymer (A) covers the polymer (B) and is divided into 5 to 30 in the fiber cross section. A polyester composite fiber, wherein the mass ratio (A / B) of the polymer (A) to the polymer (B) is 60/40 to 20/80.
(2) The polyester composite fiber according to (1), wherein the single fiber constituting the polyester split-type composite fiber has a hollowness of 1 to 30%.

  According to the present invention, it is a polyester composite fiber that is excellent in yarn-making property and processability, and a polyester composite fiber that has excellent heat retention when made into a fabric can be obtained. Furthermore, when the hollowness of the single fiber constituting the composite fiber is 1 to 30%, particularly excellent heat retention performance can be exhibited when the fiber is made.

The cross-sectional shape of the 8-part dividing type of fiber which is an embodiment of the present invention is shown. The cross-sectional shape of a 20-split type fiber that is an embodiment of the present invention is shown. The cross section shape of the 4-part dividing type of the fiber which is the mode of comparative example 7 is shown. 10 shows a cross-sectional shape of a 40-split type fiber that is an aspect of Comparative Example 8.

  Hereinafter, the present invention will be described in detail.

  The polymer (A) constituting the conjugate fiber of the present invention is not particularly limited as long as it is a polyester resin, and for example, aromatic polyester, aliphatic polyester, and the like are preferably used.

  Examples of the aromatic polyester include polyesters mainly composed of polyalkylene terephthalate such as polyethylene terephthalate (PET), polybutylene terephthalate, and polytrimethylene terephthalate.

  Examples of aliphatic polyesters include poly-α-hydroxy acids such as polylactic acid and polyglycolic acid, poly-β-hydroxyalkanos such as poly-β-hydroxybutyric acid and poly- (β-hydroxybutyric acid / β-hydroxyvaleric acid). And poly-ω-hydroxyalkanoates such as poly-β-propiolactone and poly-ε-caprolactone.

  Aromatic polyester, aliphatic polyester, and the like may be those obtained by copolymerizing the copolymerization components shown below. Representative examples of copolymer components include isophthalic acid, 5-alkali metal sulfoisophthalic acid, aromatic dicarboxylic acids such as 3,3′-diphenyldicarboxylic acid, aliphatic dicarboxylic acids such as adipic acid, sebacic acid and succinic acid, and diethylene glycol. And copolymer components such as aliphatic, alicyclic diol, and P-hydroxybenzoic acid such as 1,4 butanediol and 1,4 cyclohexanediol.

  The polymer (B) constituting the conjugate fiber of the present invention is not particularly limited as long as it is a polyester resin, and for example, aromatic polyester, aliphatic polyester, and the like are preferably used.

  Examples of the aromatic polyester include polyesters mainly composed of polyalkylene terephthalate such as polyethylene terephthalate (PET), polybutylene terephthalate, and polytrimethylene terephthalate.

  Examples of aliphatic polyesters include poly-α-hydroxy acids such as polylactic acid and polyglycolic acid, poly-β-hydroxyalkanos such as poly-β-hydroxybutyric acid and poly- (β-hydroxybutyric acid / β-hydroxyvaleric acid). And poly-ω-hydroxyalkanoates such as poly-β-propiolactone and poly-ε-caprolactone.

  The aromatic polyester and aliphatic polyester may be obtained by copolymerizing the following copolymer components. Representative examples of copolymer components include isophthalic acid, 5-alkali metal sulfoisophthalic acid, aromatic dicarboxylic acids such as 3,3′-diphenyldicarboxylic acid, aliphatic dicarboxylic acids such as adipic acid, sebacic acid and succinic acid, and diethylene glycol. And copolymer components such as aliphatic, alicyclic diol, and P-hydroxybenzoic acid such as 1,4 butanediol and 1,4 cyclohexanediol.

  The polyester composite fiber of the present invention may contain commonly used additives, matting agents, antistatic agents, antioxidants, etc., as long as the effects of the present invention are not impaired. good.

  In the present invention, the polymer (B) contains 1 to 20% by mass of silica having a secondary average particle size of 0.05 to 3.0 μm and a ratio of the secondary particle size of 5 μm or more to 10% by volume or less. It is necessary.

  The secondary average particle diameter of silica is the average particle diameter of silica after being dispersed in the polyester resin, and after dissolving the polyester composite fiber in a mixed solvent of phenol / tetrachloroethane = 50/50 mass% as described later Although it measures on a predetermined condition, 0.05-3.0 micrometers is required and 0.1-1.7 micrometers is preferable. When the average particle diameter is less than 0.05 μm or exceeds 3.0 μm, the yarn-making property is remarkably deteriorated.

  The ratio of silica having a secondary particle diameter of 5 μm or more needs to be 10% by volume or less, and preferably 5% by volume or less. In the conjugate fiber of the present invention, for example, by using a polyester-based resin polymerized by a production method described later, it becomes possible to reduce the amount of coarse silica particles present in the polyester-based resin. This is preferable because the fiber-forming property at the time of fiber formation by melt spinning can be improved. The presence of 10% by volume or more of silica having a size of 5 μm or more is not preferable because the spinning performance is significantly deteriorated.

  The secondary maximum particle size of silica is preferably less than 10 μm, more preferably less than 5 μm. When the maximum particle size is 10 μm or more, the yarn-making property is remarkably deteriorated.

  In the present invention, the polyester composite fiber containing specific silica is used, and further having a specific divided cross-sectional shape, it is possible to obtain a polyester composite fiber exhibiting remarkable heat retention when made into a fabric with good operability. be able to.

  The silica content in the polymer (B) needs to be 1 to 20% by mass, and preferably 2 to 15% by mass. Silica has an effect of absorbing heat rays and has a low thermal conductivity, so it has excellent heat insulation properties and imparts excellent heat retention to the entire fiber. For this reason, when the content is less than 1% by mass, the silica content in the composite fiber is small, so that a sufficient heat retaining effect is not exhibited. When the content exceeds 20% by mass, the content in the composite fiber becomes too high, so that the flexibility of the yarn is likely to be lost and brittle fibers may be formed, and coarse particles in which silica is aggregated during spinning are likely to be generated. For this reason, the yarn forming property and workability may be remarkably deteriorated.

  The cross section of the composite fiber of the present invention requires that the polymer (A) covers the polymer (B). When the polymer (B) is exposed on the surface of the single fiber, the silica contained in the polymer (B) is exposed on the surface, which is not preferable because the yarn forming property and workability are remarkably deteriorated.

  The mass ratio of the polymer (A) to the polymer (B) (polymer (A) / polymer (B)) needs to be 60/40 to 20/80, and is preferably 50/50 to 30/70. When the ratio of the polymer (B) is 40% or less, the ratio of the polymer (B) in the cross section of the single fiber is low, and a sufficient heat retaining effect cannot be obtained. Further, when the ratio of the polymer (B) exceeds 80%, the heat retaining effect can be sufficiently obtained, but the filamentous flexibility is easily lost, and the polymer (A) forming the outer peripheral portion of the fiber becomes brittle. Since the thickness is reduced, the silica contained in the polymer (B) is exposed on the fiber surface, and the yarn-making property and workability are significantly deteriorated.

  In the composite fiber of the present invention, the polymer (B) needs to be divided into 5 to 30 by the polymer (A) in the cross section of the fiber, and is preferably divided into 6 to 25. . When the number of divisions is 4 or less, since the mass of the polymer (A) divided is large, the heat retention effect due to the division of the polymer (B) is not improved, which is not preferable. When the number of divisions exceeds 30, the size of one piece of the divided polymer (B) becomes non-uniform, and not only the heat retention effect due to the division is not obtained, but also the quality of the fabric is remarkably impaired.

  In the present invention, when the composite fiber in which the polymer (B) is divided into 5 to 30 by the polymer (A) is applied to the fabric, the mechanism for improving the heat retaining property of the fabric is not clear, but it contains, for example, silica. By dividing the polymer (B) whose thermal conductivity has been lowered by the polymer (A), the movement of heat transmitted through the fiber is slowed, so that it is estimated that an excellent heat retaining effect is exhibited. .

  In this invention, it is preferable that the hollowness of the single fiber which comprises a composite fiber is 1 to 30%, 5 to 20% is more preferable, and 7 to 15% is still more preferable. Since the single fiber has a hollow portion, air is held in the hollow portion of the single fiber, so that the heat insulation effect derived from silica and the heat insulation effect derived from air have a synergistic effect, so that the heat retention becomes more remarkable when the fabric is formed. It expresses performance. If the hollowness exceeds 30%, peeling of the hollow part may occur during yarn production, or when an external force is applied during post-processing, the hollow part may be crushed and air may not be retained. Since the heat retention improvement by the heat insulation effect which originates in this falls, it is not preferable.

  Next, an example is given and demonstrated about the manufacturing method of the composite fiber of this invention.

  In the production method of the present invention, it is preferable to use silica having a primary average particle diameter of 0.05 to 3.0 μm and a ratio of primary particle diameter of 5 μm or more of 10% by volume or less.

  The primary average particle diameter of silica is the average particle diameter of silica before being dispersed in the polyester resin, and an aqueous solution containing silica is measured under predetermined conditions as described later. Preferably, 0.1 to 1.7 μm is more preferable. When the primary average particle diameter is less than 0.05 μm or exceeds 3.0 μm, the secondary average particle diameter is not preferably in the preferred range, which is not preferable.

  The proportion of silica having a primary particle diameter of 5 μm or more in silica is preferably 10% by volume or less, and more preferably 5% by volume or less. If the silica having a primary particle diameter of 5 μm or more is present in an amount exceeding 10% by volume, the secondary average particle diameter is hardly within a preferable range, and the spinning property is significantly deteriorated.

  The primary maximum particle diameter of silica is preferably less than 10 μm, more preferably less than 5 μm. When the primary maximum particle diameter is 10 μm or more, the secondary maximum particle diameter is difficult to be in a preferable range, and the yarn-making property is remarkably deteriorated.

  In the production method of the present invention, it is preferable to use a polyester resin in which the silica is dispersed in ethylene glycol, stirred and dispersed, and then charged into a polyester oligomer for polymerization.

  The silica concentration in the silica / ethylene glycol dispersion in which silica is dispersed in ethylene glycol is preferably 1 to 30% by mass, and more preferably 2 to 20% by mass. If the silica concentration is less than 1% by mass, it is necessary to add a large amount of the dispersion to the polymerization solution, so that the temperature of the polyester oligomer during the polymerization may be lowered and solidify easily. Time is required and the amount of ethylene glycol used is increased, which is not preferable from the viewpoint of productivity. On the other hand, if it exceeds 30% by weight, coarse particles are likely to be generated due to aggregation of silica, which is not preferable.

  The stirring / dispersing treatment of the silica / ethylene glycol dispersion refers to stirring / dispersing treatment such as ultrasonic treatment or high-pressure collision (shearing) treatment such as homo-jetter. For example, after adding silica in a powder state to a predetermined concentration while stirring, the stirring and dispersing treatment may be performed. In order to improve the dispersibility of silica in the glycol component, silica may be subjected to a surface treatment, or a pH adjuster may be added to the dispersion.

  As a method for producing a polyester resin constituting the core, terephthalic acid is used as the dicarboxylic acid component, ethylene glycol is used as the glycol component, and the molar ratio of terephthalic acid to ethylene glycol is terephthalic acid: ethylene glycol = 1: 1. 4 to 1: 1.8 is charged into a polymerization kettle, and an esterification reaction is performed while stirring in a molten state at a polymerization pressure of 30 to 500 hPa and a polymerization temperature of 240 to 270 ° C. to obtain a polyester oligomer. At this time, other dicarboxylic acid components and / or glycol components may be added within a range that does not impair the properties of the resin.

  Subsequently, after adding the silica / ethylene glycol dispersion and the polycondensation catalyst subjected to the above-mentioned stirring and dispersing treatment to the polyester oligomer, the pressure in the polymerization kettle is 0.2 to 1.3 hPa while melting and stirring at 270 to 290 ° C. The polycondensation reaction is performed for about 1 to 8 hours under reduced pressure to obtain a polyester resin. The polyester-based resin can be obtained by discharging the polyester-based resin from the base of the polymerization can, cooling and solidifying, and then chipping.

  The polycondensation catalyst is not particularly limited, but metal compounds such as antimony, germanium, tin, titanium, zinc, aluminum, magnesium, potassium, calcium, sodium, manganese, cobalt, sulfosalicylic acid, o-sulfobenzoic anhydride, etc. And organic sulfonic acid compounds.

The addition amount of the catalyst is not particularly limited, but is preferably 0.5 × 10 ^{−4 to} 6.0 × 10 ⁻⁴ mol with respect to 1 mol of the acid component constituting the polyester from the viewpoints of polymerizability and thermal stability. 1.0 × 10 ^{−4 to} 5.0 × 10 ⁻⁴ mol is more preferable.

  In the production method of the present invention, the spinning method is not particularly limited as long as the specific polyester-based resin described above is used in a specific amount to form a specific divided composite structure. For example, a high-speed spinning with a spinning speed of 2000 m / min or more is possible. POY method for obtaining a semi-undrawn yarn by the above method, or a method in which melt spinning is performed once at a low speed spinning of less than 2000 m / min or a high speed spinning of 2000 m / min or more, and then the wound yarn is drawn and heat-treated, without being wound once Subsequently, a direct spinning drawing method in which drawing is performed can be mentioned.

  In the present invention, the composite fiber obtained as described above or the composite fiber having a hollow portion may be used as it is in a fabric, but post-processing such as false twist crimping, indentation, and knit deniting is performed. It is preferable to fabricate the fabric after it has been obtained because higher heat retention can be obtained. In particular, the composite fiber having a hollow portion is preferably false twisted so that the hollow portion is not crushed under the conditions described later.

  The draw ratio in the false twist crimping process is preferably 1.05 to 1.5 times, and more preferably 1.1 to 1.4 times. By setting the draw ratio to 1.05 to 1.5 times, molecular orientation and crystallinity can be improved, and a crimped yarn excellent in heat resistance and strength can be obtained.

  The false twist coefficient in the false twist crimping process is preferably 26000 to 35000, more preferably 26000 to 33000, and even more preferably 27000 to 32000. By setting the false twist coefficient to 26000 to 35000, a crimped yarn having a firm crimp can be obtained.

  It is preferable that the heater temperature in said false twist crimping process is 140-220 degreeC, and it is more preferable that it is 160-200 degreeC. By setting the heater temperature to 140 to 220 ° C., the crimp is strengthened, and in addition, the effect of improving the crystallinity of the crimped yarn is achieved.

  When false twisting is applied to the conjugate fiber of the present invention, the crimping can be made stronger by selecting the false twisting conditions described above, so that the heat retention of the resulting fabric is more remarkable. To improve.

  The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto. In addition, the measuring method in an Example and a comparative example is as follows.

1. Intrinsic viscosity [η]
It measured based on the conventional method on the conditions of the temperature of 20 degreeC by using the equal mass mixture of a phenol and ethane tetrachloride as a solvent.

2. Primary average particle diameter of silica, ratio of primary particle diameter of 5 μm or more After silica particles are dispersed in deionized water, the diffraction / scattering light intensity is 40 using a laser diffraction particle size distribution analyzer (SALD-7100, manufactured by Shimadzu Corporation). After adjusting the dilution with water so as to be in the range of ˜60%, the average value measured four times was taken as the primary average particle diameter and the ratio of the primary particle diameter of 5 μm or more.
The primary maximum particle size was also measured by the same method.

3. Ratio of secondary average particle diameter of silica, secondary particle diameter of 5 μm or more The polyester composite fiber of the present invention is dissolved in a mixed solvent of phenol / tetrachloroethane = 50/50 mass% so as to be 5 mass%, and obtained. The diluted solution was measured with a laser diffraction particle size distribution measuring apparatus (SALD-7100 manufactured by Shimadzu Corporation) so that the diffraction / scattered light intensity was in the range of 40 to 60%, and the average of four times was measured. The value was an average particle diameter and a ratio of particles of 5 μm or more.
The secondary maximum particle size was also measured by the same method.

4). Silica content in the polymer (B) Take out the single fiber from the polyester composite fiber, take the cross-sectional shape of the single fiber in an enlarged photo, calculate the area of the whole single fiber and the area of the polymer (B) on the photo, polymer The mass ratio (%) of the polymer (B) was calculated in consideration of the specific gravity of the polyester resin used in (A) and the polymer (B). Next, after putting about 1 g of polyester composite fiber in a crucible and weighing, incineration treatment at 400 ° C. × 2 h, further 600 ° C. × 3 h, and sufficiently cooling to room temperature while suppressing moisture absorption in a desiccator, The amount of silica (g) in the crucible residue was measured, and calculated by the following formula using the ratio of the core.
Silica amount in polymer (B) (mass%) = silica amount in crucible residue (g) / (total mass of sample before incineration treatment (g) × mass ratio of polymer (B) in composite fiber (% ) / 100)

5. Heat retention property A fabric having a basis weight of 135 g / cm ² is produced using the obtained conjugate fiber. Further, a fabric having a basis weight of 135 g / cm ² is prepared using a round cross-sectional 84T48 polyester fiber containing 0.4% of titanium oxide as a comparative sample. After the fabric is wrapped around the stainless steel bottle, a thermocouple is attached to the center of the stainless steel bottle, the temperature inside the stainless steel bottle is heated to 45 ° C, and the temperature inside is stabilized at 45 ° C for 1 minute. The stainless steel bottle was moved to an environment of 20 ° C., and the temperature change until the temperature inside the bottle reached 25 ° C. was read.
The temperature was recorded every 10 seconds and the temperature change was read.
Based on the temperature change of the fabric using the polyester fiber having the circular cross-sectional shape, the one that has a slow time to reach 25 ° C. is excellent in heat retention, and the heat retention is evaluated in the following four stages. Was passed.
◎: Slow for 61 seconds or more ○: Slow for 31-60 seconds △: Slow for 0-30 seconds ×: No difference from the reference fabric

6). Spinnability Spinnability was evaluated based on the number of cut yarns when spinning for 24 hours.
0-2 times: ○
3-5 times: △
6 times or more: ×

7. Hollowness A single fiber was extracted from a composite fiber (a composite fiber having a hollow part) (n number = 10), and a cross section taken perpendicularly to the longitudinal direction of the single fiber was taken on a transmission electron micrograph. The total area (A) of the single fiber and the area (B) of the hollow part were measured and calculated according to the following formula. The average value of n number 10 was used.
Hollowness (%) = (B / A) × 100

Example 1
-Preparation of polymer (B) A slurry of terephthalic acid and ethylene glycol (terephthalic acid: ethylene glycol (molar ratio) = 1: 1.6) was continuously supplied to the esterification reactor, at a temperature of 250 ° C and a pressure of 50 hPa. A polyester oligomer having an esterification reaction rate of 95% was obtained. This polyester oligomer was fed to a polycondensation reaction can heated to 270 ° C., and the inside of the container was replaced with nitrogen. After that, the primary average particle diameter was 0.23 μm, and the volume ratio of the primary particle diameter was 5 μm or more was 0% by volume. Is added to ethylene glycol so as to be 15% by mass. K. Using a homo-jetter (manufactured by Tokushu Kika Kogyo Co., Ltd.) and a sonolator (manufactured by SONIC. CORP), stirring and dispersion treatment was performed for 4 hours. After adding the obtained silica / ethylene glycol dispersion to the polyester oligomer so that the content of silica in the polyester resin is 10% by mass, 1 mol of antimony trioxide as the polycondensation catalyst constitutes 1 mol of the acid component constituting the polyester. against after addition so as to be 3.0 × ^{10 -4} mol, and more than 1.2hPa 1 hour after gradually reducing the pressure. The polycondensation reaction was carried out for 2 hours while stirring under these conditions, and then the obtained polyester resin was chipped by a conventional method and dried to obtain a polymer (B) constituting the core. In addition, the intrinsic viscosity of the obtained polyester resin was 0.65.
-Polyester composite fiber production As a polymer (A), a polyester resin having an intrinsic viscosity of 0.65 is used, and a polymer (B) prepared under the above conditions is used. As shown in FIG. Using a composite nozzle plate in which the polymer (B) covers the polymer (B) and the polymer (A) divides the polymer (B) into 8 parts, and the mass ratio of the polymer (A) and the polymer (B) is 40/60, Spinning was performed at a spinning speed of 3500 m / min, a spinning temperature of 290 ° C., and a discharge rate of 43 g / min, and the semi-undrawn yarn was scraped off. Subsequently, the obtained semi-undrawn yarn was drawn by a conventional method to obtain a drawn yarn of 84 dtex / 48 filament.

Example 2
The same procedure as in Example 1 was conducted except that the concentration of silica contained in the polymer (B) was changed as shown in Table 1.

Example 3
The same procedure as in Example 1 was conducted except that the ratio of the polymer (A) to the polymer (B) was changed as shown in Table 1.

Example 4
The same operation as in Example 1 was conducted except that the primary average particle diameter of silica contained in the polymer (B) was changed as shown in Table 1.

Example 5
Instead of the composite nozzle plate divided into 8 pieces, a composite nozzle plate divided into 20 pieces was used, and the number of divisions of the polymer (B) was changed as shown in Table 1, and the same procedure as in Example 1 was carried out.

Example 6
The same procedure as in Example 5 was carried out except that the composite nozzle plate was changed to the composite nozzle plate having the cross-sectional shape shown in FIG.

Examples 7-9
The same procedure as in Example 6 was performed except that the hollowness of the single fiber was changed as shown in Table 1.

Comparative Example 1
The same procedure as in Example 1 was conducted except that the concentration of silica contained in the polymer (B) was changed as shown in Table 1.

Comparative Example 2
The same procedure as in Example 1 was conducted except that the ratio of the polymer (A) to the polymer (B) was changed as shown in Table 1.

Comparative Example 3
The same procedure as in Example 1 was conducted except that the concentration of silica contained in the polymer (B) was changed as shown in Table 1.

Comparative Example 4
The same procedure as in Example 1 was conducted except that the ratio of the polymer (A) to the polymer (B) was changed as shown in Table 1.

Comparative Examples 5 and 6
The same procedure as in Example 1 was performed except that the primary average particle diameter of silica contained in the polymer (B) was changed as shown in Table 1.

Comparative Example 7
Implementation was performed except that instead of the composite nozzle plate divided into 8 pieces, a composite nozzle plate divided into 4 pieces was used, and the number of divisions of the polymer (B) was changed as shown in Table 1 to obtain the cross-sectional shape shown in FIG. Performed as in Example 1.

Comparative Example 8
It replaced with the compound nozzle plate divided | segmented into 20 pieces, and it carried out similarly to Example 8 except having used the composite nozzle plate divided | segmented into 40 pieces, and having set it as the cross-sectional shape shown in FIG.

Comparative Example 9
It carried out similarly to Example 6 except having changed the hollowness.

Comparative Example 10
The same procedure as in Example 1 was performed except that a concentric core-sheath composite nozzle plate that was not divided was used instead of the composite nozzle plate that was divided into eight.

The obtained results are shown in Table 1.

As in Examples 1 to 9, when the amount of silica, the silica secondary average particle diameter, the number of divisions, and the like were specified, the composite fiber of the present invention was obtained with good yarn-making properties, and the fabric made thereof was excellent in heat retention. It was a thing. In particular, in Examples 6 to 9 having a hollow portion, particularly remarkable heat retention was exhibited.
On the other hand, since the composite fiber of Comparative Example 1 has a low silica content of the polymer (B), and Comparative Example 2 has a small ratio of the polymer (B), sufficient heat retention cannot be obtained. It was. Since the composite fiber of Comparative Example 3 has a high silica content of the polymer (B), the secondary aggregation of silica generated during spinning is severe, and the fiber is very brittle, so that the yarn-making property is very poor. The fiber could not be collected stably. Since the composite fiber of Comparative Example 4 had a high ratio of the polymer (B) containing silica, the fiber was very brittle, so the spinnability was very poor, and the fiber could not be collected stably. The composite fiber of Comparative Example 5 has a very small primary average particle diameter of silica added to the polymer (B), and the composite fiber of Comparative Example 6 has a large primary average particle diameter of silica. Coarse particles due to secondary agglomeration of the generated silica were generated, and the spinning performance was very poor, and fibers could not be collected stably. The composite fibers of Comparative Examples 7 to 8 were inferior in heat retention because the number of divisions of the polymer (B) was not appropriate. Since the composite fiber of Comparative Example 9 had a hollowness exceeding 30%, peeling of the hollow portion occurred frequently, and the yarn-making property was very poor, and the fiber could not be collected stably. Since the concentric core-sheath conjugate fiber of Comparative Example 10 was not a conjugate fiber having a divided cross-sectional structure, it was inferior in heat retention.

A: Polymer (A)
B: Polymer (B)
C: Hollow part

Claims (2)

1-20% by mass of a polymer (A) comprising a polyester-based resin and silica having a secondary average particle size of 0.05 to 3.0 μm and a secondary particle size of 5 μm or more of 10% by volume or less A composite fiber comprising a polymer (B) made of a polyester resin, the polymer (A) covering the polymer (B) and divided into 5 to 30 in the fiber cross section, A polyester composite fiber, wherein the mass ratio (A / B) of A) to the polymer (B) is 60/40 to 20/80. The polyester composite fiber according to claim 1, wherein the single fiber constituting the polyester composite fiber has a hollowness of 1 to 30%.