JP2010138509A - Water-repelling polyester conjugated fiber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a new conjugated fiber which has excellent water-repelling performance and sufficient strength, little lowers an early time water-repelling property, even when used for a long period, repeatedly washed, or the like, and is excellent in hand. <P>SOLUTION: The water-repelling sheath-core type polyester conjugated fiber includes a specific ester-forming silicone in a polyester constituting the sheath portion, and has 1 to 50 independent protrusions based on particles in the polyester constituting the sheath portion per length of 100 μm on the surface of the fiber. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a water-repellent polyester composite fiber that does not deteriorate in water repellency even when used for a long period of time and can be suitably used for various apparel and materials.

  Conventionally, polyester fiber has been widely used as a synthetic fiber because it has many excellent properties. In recent years, it has become more highly functional, including water-repellent function and more slimy feeling for sports and casual use. There is a need for improved texture.

  Conventionally, the water-repellent function has been imparted by a method of treating the fabric with a dispersion containing a fluorine-based resin or a silicone-based resin and attaching the resin to the surface of the fabric to perform the water-repellent treatment. Yes. However, although the fabrics obtained by these processing treatments have water repellency, they have low durability, and the resin treated with the use of the fabric is liable to fall off the surface and easily lose water repellency. is doing. On the other hand, there is a problem that if the amount is sufficient to give sufficient water repellency, the texture of the fabric becomes hard. For this reason, the application of polyester fibers to sportswear such as fields where water repellency and texture are both required is greatly limited.

  In order to impart water repellency as a fabric, it can be imparted by form other than chemical water repellency. That is, by arranging the air layer densely, water repellency can be expressed by giving a structure like a lotus leaf structure or a taro leaf. For this reason, attempts have been made in the past to make a fine structure by weaving finely sized water repellent yarns at a high density, but sufficient performance has not been obtained due to insufficient water repellency of the fibers themselves.

  In contrast, Japanese Patent Laid-Open No. 62-238822 proposes a fiber obtained by melt-kneading a fluororesin, and Japanese Patent Laid-Open No. 2-26919 is obtained by kneading fluoropolymer fine particles. Fibers have been proposed. JP-A-9-302523 and JP-A-9-302524 provide fibers containing a copolymer of tetrafluoroethylene / hexafluoropropylene / vinylidene fluoride as a water repellent component in polyester. However, since a fluororesin generally has a melting point and a decomposition point close to each other, it is difficult to obtain a fiber having a stable and good yarn quality due to the influence of a polymer that has undergone decomposition heat degradation during long-term running. Further, there is a risk that the apparatus is deteriorated due to generation of hydrogen fluoride by heating.

  Further, JP-A-4-343770, JP-A-5-106171, and the like disclose attempts to make water-repellent fibers by bonding fluorine-modified silicone to the polyester fiber surface via a specific organic polymer. In this case, although the water repellency of the fiber becomes high durability to some extent, the fiber is still hard, the texture becomes hard even when it is made into a fabric, and the feeling of slime is reduced, and the environment due to the use of a fluorine compound There is a problem of increased load.

  Furthermore, JP-A-2005-105424 discloses that water resistance is imparted to the sheath polyester by containing (including copolymerization) a specific ester-reactive silicone. However, in order to achieve high water repellency, it is necessary to increase the amount of addition. For this reason, there is a problem that the strength is reduced when the fineness is used.

Japanese Patent Application Laid-Open No. 2008-248444 discloses a technique for adding silicone fine particles to polyester, but it is necessary to increase the amount of addition in order to achieve high water repellency. There was a problem to do.
As described above, a water-repellent polyester fiber having sufficient water repellency and practical durability and excellent in process stability, productivity and softness such as softness is strongly desired.

JP-A-62-238822 JP-A-2-26919 JP-A-9-302523 JP-A-9-302524 JP-A-4-343770 JP-A-5-106171 JP-A-2005-105424 JP 2008-248444 A

  The object of the present invention is to overcome the problems of the prior art, have excellent water repellency and sufficient strength, with little deterioration in initial water repellency due to long-term use or repeated washing, etc. An object of the present invention is to provide an excellent unprecedented composite fiber.

（上記式中、Ｒはアルキル基を表し、ｎは１〜１００の整数である。）
又、
エステル反応性シリコーンの含有量がポリエステル全重量に対し２〜４０重量％であり、ポリエステルと共重合しているものがエステル反応性シリコーンの全重量に対して、２０〜５０重量％の範囲である撥水性ポリエステル芯鞘型複合繊維、
が提供される。 As a result of studies conducted by the present inventors to solve such problems, the present invention is achieved by providing a structure having an independent protrusion on the fiber surface of a core-sheath composite fiber having a water-repellent polymer as a sheath component. I found. That is, according to the present invention,
A core-sheath type polyester composite fiber, wherein the water-repellent core-sheath type polyester composite fiber satisfies the following requirements:
a) Polyester which comprises a sheath part contains ester reactive silicone represented by following formula (1).
b) Polyester which comprises a sheath part contains particle | grains, and has 1-50 independent processus | protrusions per 100 micrometers in length in the fiber axis direction on the fiber surface based on this particle | grain.
c) The single yarn fineness is 0.1 to 3.0 dtex.

(In the above formula, R represents an alkyl group, and n is an integer of 1 to 100.)
or,
The content of the ester-reactive silicone is 2 to 40% by weight based on the total weight of the polyester, and the amount copolymerized with the polyester is in the range of 20 to 50% by weight based on the total weight of the ester-reactive silicone. Water repellent polyester core-sheath composite fiber,
Is provided.

  By forming protrusions on the polyester core-sheath type composite fiber containing a specific ester-forming silicone, it is possible not only to have water repellency due to silicone, but also to have contact areas between water droplets and fibers by having protrusions on the fiber surface. , The water droplets on the fiber surface are easy to roll, and even with a small silicone content, high water repellency and high durability water repellency can be achieved. Further, it is possible to provide polyester having fineness, strength, excellent texture and unique touch.

Hereinafter, the water-repellent polyester core-sheath composite fiber of the present invention will be described in detail.
The water-repellent polyester core-sheath composite fiber of the present invention is a composite fiber having a core-sheath structure. Since the polymer constituting the sheath portion exhibits water repellency, as described later, it is necessary to use a polyester containing an ester-reactive silicone, and the polymer constituting the core portion is not particularly limited. It is preferable from the standpoint of yarn production that it is the same kind of polyester as the sheath not containing.

  The polymer constituting the water-repellent polyester core-sheath composite fiber of the present invention is a polyester mainly composed of polyester and mainly composed of components formed from aromatic dicarboxylic acid and alkylene glycol. A polyester having an aromatic dicarboxylic acid and an alkylene glycol as a repeating unit is a polyester synthesized from a corresponding aromatic dicarboxylic acid and / or an ester-forming derivative thereof and a diol, and as long as the physical properties are not impaired as a general-purpose resin. Other components may be copolymerized depending on the purpose. Examples of the ester-forming derivative include lower alkyl esters having 1 to 6 carbon atoms, lower aryl esters having 6 to 12 carbon atoms, and acid halides. The main repeating unit means that 70 mol% of all repeating units constituting the polyester is composed of a component formed from the aromatic dicarboxylic acid and alkylene glycol.

  The aromatic dicarboxylic acid and / or ester-forming derivatives thereof include terephthalic acid, 2,6-naphthalenedicarboxylic acid, isophthalic acid, 1,4-cyclohexyl dicarboxylic acid, adipic acid, sebacic acid, phthalic acid, phthalic anhydride 5-sodium sulfoisophthalic acid, 5-tetrabutylphosphonium sulfoisophthalic acid, dimethyl terephthalate, dimethyl 2,6-naphthalenedicarboxylate, dimethyl isophthalate, dimethyl 1,4-cyclohexanedicarboxylate, dimethyl adipate, dimethyl sebacate Dimethyl phthalate, dimethyl 5-sodium sulfoisophthalate, or dimethyl 5-tetrabutylphosphonium sulfoisophthalate. In addition to the dimethyl ester and other lower alkyl esters as described above, acid chlorides may be used as the ester-forming derivative. Among these, it is particularly preferable to use terephthalic acid, 2,6-naphthalenedicarboxylic acid, dimethyl terephthalate, or dimethyl 2,6-naphthalenedicarboxylate.

  As diols, ethylene glycol, 1,4-butanediol, diethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 2,2-dimethyl-1,3-propanediol, dipropylene glycol, 1,6 -Hexanediol, 1,4-cyclohexanedimethanol, dimethylolpropionic acid, poly (ethylene oxide) glycol, or poly (tetramethylene oxide) glycol can be mentioned, particularly ethylene glycol, 1,3-propylene glycol or It is preferable to use 1,4-butanediol.

  Each of these dicarboxylic acids and / or ester-forming derivatives thereof and diols may be used alone or in combination of two or more. Polyesters obtained from these preferred combinations are polyethylene terephthalate, polybutylene terephthalate, polyethylene-2,6-naphthalate, polytrimethylene terephthalate, polytrimethylene-2,6-naphthalate, polytetramethylene-2,6- Naphthalate is preferably used in the polyester of the present invention. Of these, polyethylene terephthalate and polybutylene terephthalate having a good balance of mechanical properties and moldability are particularly preferable.

  In order to impart water repellency to the polyester constituting the water-repellent polyester core-sheath composite fiber of the present invention, it is necessary to use a polyester containing an ester-reactive silicone represented by the following formula (1) in the above-described polyester. It is.

（上記式中、Ｒはアルキル基を表し、ｎは１〜１００の整数である。）
Ｒのアルキル基は炭素数１８個以下、エステル反応性シリコーンの数平均分子量は１００００以下であり、好ましくは３００以上６０００以下であることが好ましい。数平均分子量が１００００より大きい場合は、ポリエステルとの相溶性が低下し、ポリエステル中に均一に存在させることが困難となる。

(In the above formula, R represents an alkyl group, and n is an integer of 1 to 100.)
The alkyl group of R has 18 or less carbon atoms, and the number average molecular weight of the ester-reactive silicone is 10,000 or less, preferably 300 or more and 6000 or less. When the number average molecular weight is larger than 10,000, the compatibility with the polyester is lowered, and it is difficult to make the polyester uniformly exist in the polyester.

  Furthermore, it is preferable that 2-40 weight% of this ester reactive silicone is contained with respect to polyester which forms the sheath component of the composite fiber of this invention. When the amount is less than 2% by weight, sufficient water repellency cannot be obtained as a fiber. When the amount exceeds 40% by weight, the physical properties of the polyester are impaired, the strength as the fiber is reduced, and the single yarn is 3.0 dtex. Not only the following fibers are difficult to produce, but also stable production is difficult during long-term running. Preferably it is 2 to 30 weight%, More preferably, it is 2 to 20 weight%.

  Here, including ester-reactive silicone means that the ester-reactive silicone is incorporated into the molecular chain by chemical bonding to the polyester and copolymerized, and the polyester does not chemically bond and exists in a blended state. It means that both are included. The non-copolymerized component is stably present in the polyester in the blended state and does not adversely affect the fiberization. This reason is presumed that the polyester copolymerized with the ester reactive silicone may stabilize the unreacted ester reactive silicone moiety.

  Moreover, in this invention, it is preferable that what is copolymerized with polyester among the ester reactive silicone which polyester contains is 20 to 50 weight% with respect to the total weight of ester reactive silicone. If it is less than 20%, the dispersibility of the ester-reactive silicone in a blend state deteriorates in the polyester, and the spinning property is lowered. If it exceeds 50%, the physical properties are impaired, the spinning property is lowered, and fluff is generated. Cause. The copolymerization amount of the ester reactive silicone is preferably 25 to 40% by weight based on the total weight of the ester reactive silicone.

  What is necessary is just to synthesize | combine by the well-known arbitrary methods as a method of obtaining polyester containing the ester reactive silicone of this invention. For example, when the dicarboxylic acid component is terephthalic acid, a method of directly esterifying terephthalic acid and alkylene glycol, and a transesterification reaction between a lower alkyl ester of terephthalic acid such as dimethyl terephthalate and alkylene glycol, or terephthalic acid In the first stage, in which a glycol ester of terephthalic acid is produced by a method of reacting with an alkylene oxide, followed by polycondensation until the desired degree of polymerization is achieved by heating under reduced pressure in the presence of a polymerization catalyst. However, either method is possible. From the viewpoint of satisfying the copolymerization ratio, the ester-reactive silicone compound is preferably added before the end of the polycondensation reaction and before the end of the polycondensation reaction. good. The proportion of the ester-reactive silicone compound copolymerized can be adjusted by the addition timing and addition amount.

  The water-repellent polyester core-sheath type composite fiber of the present invention is required to have 1-50 independent protrusions (hereinafter sometimes abbreviated as particle protrusions) per 100 μm in length on the fiber surface. . Here, the particle protrusion means that the particle is exposed in a convex shape on the fiber surface or is raised together with the polymer.

The particle protrusion on the fiber surface reduces the wet area with the fiber surface, which is the base material, by forming an air layer when water or other liquid droplets come into contact with the fabric after forming the fabric. The effect of improving water performance is expressed. Since the contact area with the droplet should be as small as possible, it is preferable that the protrusions are independently raised from the fiber surface.
In order to form the particle protrusions, the particles are contained in the sheath polyester of the water-repellent polyester core-sheath composite fiber of the present invention.

The particles used in the present invention may be either inorganic or organic, but inorganic particles are preferred from the viewpoint of heat resistance and handling. Examples of the inorganic particles include silicon oxide, titanium oxide, alumina, barium sulfate, kaolinite, carbon black, and modified products thereof, and these may be used alone or in combination.
The shape of the particles used in the present invention is not particularly limited, but spherical particles are preferably used.

  Next, the height of the particle protrusion is preferably 1/10 to 1/2, more preferably 1/5 to 1/3 of the fiber diameter. If the ratio exceeds 1/2, the shape of the protrusion is too large, and the original function of void formation is lost to promote wettability with the droplets. If the ratio is less than 1/10, the effect of addition is difficult to obtain.

  Although the size of the particles depends on the fineness and the core-sheath ratio, the average particle size is preferably 0.1 to 10 μm or less. If it exceeds 10 μm, the filtration pressure in the pack tends to increase during spinning, and if it is less than 0.1 μm, it is difficult to obtain the effect of addition. The particle size is preferably 0.5 to 7 μm.

  Further, the amount of the particle protrusions needs to be 1 to 50 per 100 μm fiber length. If it is less than 1 or exceeds 50, the spacing between the protrusions becomes too fine, and it becomes difficult to exhibit a remarkable effect. Preferably it is 2-20.

  The method of adding these particles to the polyester is not particularly limited. The powder is blended into the chip, a master batch is prepared with a base polymer in advance, and the master batch is blended, or the polyester resin is polymerized. Sometimes it can be added.

  The water-repellent polyester core-sheath composite fiber of the present invention preferably has a single yarn fineness of 0.1 to 3.0 dtex in order to highlight the softness when it is made into a woven or knitted fabric. It is practically difficult to produce a composite fiber of less than 0.1 dtex, and if it exceeds 3.0 dtex, the single yarn becomes thick, so that a soft texture cannot be obtained and the water repellency is also lowered. A preferred range is 0.5 to 1.5 dtex.

  The sheath / core ratio of the core-sheath composite fiber is preferably in the range of 70/30 to 5/95. When the number of sheaths is larger than 70/30, the physical properties are significantly lowered, the productivity is lowered, and it is difficult to obtain a finer one. If it exceeds 5/95, the thickness of the sheath becomes too thin and control becomes difficult, and the sheath is broken and the core is exposed, so that there is a high possibility that the water repellency is lowered or dyeing spots are caused. More preferably, it is 50 / 50-10 / 90, and it is especially preferable that it is 40 / 60-20 / 80.

  The water-repellent polyester core-sheath type conjugate fiber of the present invention can be produced by a known method using a known conjugate fiber spinning device. For example, by appropriately selecting the polyester of the core part, By not containing reactive silicone, the strength in terms of physical properties can be ensured, so that the spinning speed can be increased to produce efficiently. For example, a core-sheath type composite fiber is extruded into a fiber shape in a molten state, melt-spun at a speed of 500 to 3500 m / min, and then directly stretched and heat-treated without being wound once. Other preferred methods include melt spinning and stretching at a speed of 1000 to 5000 m / min, melt spinning at a high speed of 5000 m / min or more, and a method for omitting the stretching step depending on the application. It can be excellent in stability.

  A part of the polyester fiber thus obtained may be removed as necessary. As a method of removing, it can carry out easily by processing with the aqueous solution of an alkali compound, after extending | stretching heat processing or false twisting, or after making it into a fabric.

  Examples of the alkali compound used here include sodium hydroxide, potassium hydroxide, tetramethylammonium hydroxide, sodium carbonate, potassium carbonate and the like. Of these, sodium hydroxide and potassium hydroxide are particularly preferred.

  The concentration of the aqueous solution of the alkali compound varies depending on the type of the alkali compound and the processing conditions, but is usually preferably in the range of 0.01 to 40% by weight, particularly preferably in the range of 0.1 to 30% by weight. The treatment temperature is preferably in the range of room temperature to 100 ° C., and the treatment time is usually in the range of 1 to 4 hours. Further, the amount of elution and removal by the treatment of the aqueous solution of the alkali compound should be in the range of 2% by weight or more with respect to the fiber weight.

The water-repellent polyester core-sheath type composite fiber obtained by the method of the present invention has any additive as necessary, such as a catalyst, an anti-coloring agent, a heat-resistant agent, a flame retardant, a fluorescent whitening agent, and a matting agent. Further, a colorant or the like may be contained.
The woven or knitted fabric using the fibers thus obtained has excellent water repellency, does not deteriorate water repellency due to long-term use, repeated washing, etc., and has an excellent texture.

  The cross-sectional shape of the water-repellent polyester core-sheath type composite fiber of the present invention can be any shape depending on the application, for example, in addition to a circular shape, a modified cross-section such as a triangle, flat shape, star shape, V shape, etc. The hollow cross section of can be illustrated.

  Hereinafter, the present invention will be described more specifically with reference to examples. The present invention is not limited to these examples. Each item in the examples was measured by the following method.

(1) Strength Under a 20 ° C. and 65% RH atmosphere, the strength at break was measured with a tensile tester under the conditions of a sample length of 20 cm and a speed of 20 cm / min. The number of measurements was 10, and the average was taken as each intensity.

(2) Contact angle (fiber repellency)
Polyester fibers are extracted from the same fabric used for water repellency, and then a single yarn is collected and distilled water is used using an automatic micro contact angle measuring device “MCA-2” manufactured by Kyowa Interface Science Co., Ltd. Then, the contact angle between the fiber and the water droplet when 500 pl of distilled water was dropped onto the surface of the single yarn of the fiber was measured by the θ / 2 method, and it was determined that the larger the contact angle, the better the water repellency.

(3) Water repellency (water repellency of fabric)
Using the polyester fibers obtained in each of Examples and Comparative Examples as warp and weft, a plain fabric having a basis weight of 75 g / m ² was woven, refined and dried by a conventional method, and heat-set at 180 ° C. Using this fabric, the spray test method of JIS L-1092 was repeated 5 times for the same sample, and evaluation was performed by displaying the score on the wetness of the fabric.
100 points: No wet or water droplets on the surface 90 points: No wet surface, but small water droplets 80 points: Small individual water droplets on the surface 70 points: Surface More than half of the surface is wet and small individual wetness penetrates the cloth 50 points: The entire surface is wet 0 points: The front and back surfaces are wet throughout

(4) slime feeling Using the same fabric as evaluated for water repellency, sensory evaluation was performed by 5 panelists, 3: all were judged to be extremely good,
2: What more than 3 people judged good,
1: What is judged as bad by 3 or more people (bad)
And ranked in three stages.

(5) Number of protrusions per fiber length:
The fiber side surface was photographed with an electron microscope at × 1000 magnification, and the number of protrusions having a height of 1/10 or more of the fiber diameter per 100 μm length was measured for 10 fibers, and the average value was obtained. It was.

(6) Amount of contained silicone compound:
The amount of the ester reactive silicone contained in the polyester composition was quantified by 1H-NMR method. Furthermore, the polyester sample was dissolved in an appropriate solvent, a poor solvent was added to perform reprecipitation operation, and 1H-NMR measurement was also performed on the solid matter obtained by filtration. The amount of the ester reactive silicone copolymerized in the polyester is quantified from the value of the measurement result after the latter reprecipitation operation, and the value of the measurement result before the reprecipitation and the value of the latter measurement result are determined. The amount of blended silicone compound was quantified from the difference. In addition, in the chemical structure of the ester-reactive silicone, for the blended components, the components in the solvent of the reprecipitation operation are collected components, and for the copolymerized components, the residual components after hydrolysis of the reprecipitated polyester Can be measured.

[Example 1]
100 parts by weight of dimethyl terephthalate, 60 parts by weight of ethylene glycol, 10 parts by weight of an ester-reactive silicone compound (a compound in which R in the general formula (1) is an ethyl group, n = 9, FM-DA11 manufactured by Chisso), manganese acetate 0.031 part by weight of tetrahydrate was charged into the reactor, and the temperature was raised from 140 ° C. to 240 ° C. over 3 hours in a nitrogen gas atmosphere, and transesterification was performed while removing methanol to be purified out of the system. After the transesterification reaction is completed, 0.024 parts by weight of phosphoric acid as a stabilizer and 0.04 parts by weight of antimony trioxide as a polycondensation reaction catalyst are added, and then the temperature is raised to 285 ° C. A condensation reaction was performed to obtain a silicone-containing polyester. The polyester obtained had an intrinsic viscosity of 0.65 (35 ° C. in orthochlorophenol).

On the other hand, 3% by weight of this polyester chip and 3% by weight of a polyethylene terephthalate masterbatch containing 30% by weight of inorganic particles (silton JC-50 manufactured by Mizusawa Chemical) with an average particle size of 5 μm whose main component is sodium calcium aminosilicate hydrate. After chip blending and drying to a moisture content of 70 ppm or less, the polymer was melted in an extruder at a melting temperature of 300 ° C. and polymerized without using an ester-reactive silicone compound, and an intrinsic viscosity of 0.64 (35 ° C., orthochloro). Polyethylene terephthalate (in phenol) was dried to a similar moisture content, and then melted separately in a separate extruder at a melting temperature of 285 ° C. Each molten polymer is made of polyester containing ester-reactive silicone as a sheath component, using a core-sheath type composite fiber die having 36 round discharge holes, and a sheath / core weight ratio of 30. After being discharged at a spinning speed of 1000 m / min, the film was stretched at a preheating temperature of 90 ° C., a heat setting temperature of 120 ° C., and a draw ratio of 3.2 times without being wound up, and 3200 m / min. Winded up at a speed of The obtained sheath-core composite polyester multifilament had a fineness of 54 dtex, a single yarn fineness of 1.5 dtex, a strength of 3.8 cN / dtex, and an elongation of 28%.
A taffeta fabric was prepared using the obtained fibers. The obtained fabric was excellent in water repellency and had a supple and slimy texture.
Table 1 shows the physical properties of the obtained core-sheath composite multifilament.

[Comparative Examples 1-2]
In Example 1, only a silicone-containing polyester is used for the sheath, melted in an extruder at a melting temperature of 300 ° C., and a single thread is produced under the same conditions as in Example 1 using a die having 36 circular discharge holes. This was designated as Comparative Example 1. Further, Comparative Example 2 was obtained so that the inorganic particle content in Example 1 was 1%. Table 1 shows the physical properties of these core-sheath multifilaments.
Comparative Example 1 in which no protrusion was formed and Comparative Example 2 in which the number of protrusions was small both had some water repellency, but were inferior to Example 1.

[Comparative Examples 3 to 4]
Comparative Example 3 was obtained by adding inorganic particles in the same manner as in Example 1 using the same polymer as in the core part without using ester reactive silicone in the sheath part in Example 1. Further, Comparative Example 4 was prepared in the same manner as in Example 1 so that the sheath ratio was 20% and the inorganic particles were 20% with respect to the sheath portion. Table 1 shows the physical properties of the obtained core-sheath composite multifilament.
In Comparative Example 3 where no silicone-containing polyester was used for the sheath, the water repellency was inferior. Further, in Comparative Example 4 in which the number of protrusions was large and outside the scope of the present invention, the water repellency was conversely lowered, and neither the feeling of slime was felt at all in the texture.

  Polyester fabric with high durability, water repellency, and excellent strength and texture, sports use, casual use, men's and women's suits, and other industrial uses such as surgical clothing, tent fabrics, and filters It is also useful.

Claims (3)

A water-repellent core-sheath type polyester composite fiber which is a core-sheath type polyester composite fiber and satisfies the following requirements.
a) Polyester which comprises a sheath part contains ester reactive silicone represented by following formula (1).
b) Polyester which comprises a sheath part contains particle | grains, and has 1-50 independent processus | protrusions per 100 micrometers in length in the fiber axis direction on the fiber surface based on this particle | grain.
c) The single yarn fineness is 0.1 to 3.0 dtex.

(In the above formula, R represents an alkyl group, and n is an integer of 1 to 100.)   The water-repellent core-sheath polyester composite fiber according to claim 1, wherein the sheath / core ratio is in the range of 70/30 to 5/95.   The ester-reactive silicone content is 2 to 40% by weight based on the total weight of the polyester, and the ester-reactive silicone that is copolymerized with the polyester is 20 to 50% based on the total weight of the ester-reactive silicone. The water-repellent core-sheath type polyester composite fiber according to claim 1, which is in a range of% by weight.