JPH06108313A - Splittable type conjugate fiber dyeable with cationic dye - Google Patents

Abstract

PURPOSE:To obtain the subject a conjugate fiber having a sparingly alkali- soluble component having a high intrinsic viscosity by adding a specific additive to a sulfonate group-containing aromatic polyester of the sparingly alkali-soluble component polymer adjacent to a readily alkali-soluble component. CONSTITUTION:This conjugate fiber is obtained by including 1-5wt.% glass transition point lowering agent and 0.1-1wt.% inorganic fine particle in a sulfonate group-containing aromatic polyester of (A) a sparingly alkali-soluble component (A) divided into >=2 parts with (B) a readily alkali-soluble component. This splittable type conjugate fiber is treated with an alkali to afford the ultrafine fiber, excellent in mechanical properties, fiber manufacturing properties, processability, unwinding properties, color fastness, hand, etc., and dyeable with a cationic dye.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a splittable conjugate fiber comprising an alkali hardly soluble component and an alkali easily soluble component, and more specifically, a cationic dye-dyeable ultrafine fiber obtained by dividing the conjugate fiber with an alkaline aqueous solution. The present invention relates to a splittable conjugate fiber for obtaining.

[0002]

Polyester, especially polyethylene terephthalate, has excellent mechanical and chemical properties and is widely used as a fiber for clothing and industrial materials. In particular, ultrafine fibers made of such polymers are used as functional fibers.
The field of sports clothing that uses moisture-proof and moisture-permeable properties, the cleaning of glasses that uses flexibility and the cleaning function, the cleaning cloth for various devices,
Applications are expanding to brushed clothing and the like that have a peach-skin-like feel. However, polyester fibers are inferior in dyeability, and dyeing with dyes other than disperse dyes is difficult. Further, the polyester ultrafine fibers have a drawback that the color development is poor because the fiber fineness is small. It is said that this is because when the fiber fineness becomes small, the surface area of the fiber becomes large, and light is diffusely reflected and appears to be pale or white.

Various methods for improving the dyeability of this polyester fiber have been proposed. One of them has been to copolymerize an isophthalic acid component having a sulfonic acid metal base such as 5-sodium sulfoisophthalic acid into polyester. A method for dyeing with a cationic dye has been conventionally known (Japanese Patent Publication No. 34-10497).

[0004]

However, in order to obtain a satisfactory level of dyeability with this method, it is necessary to copolymerize a large amount of an isophthalic acid component having a metal sulfonate group with the polyester. When a large amount of isophthalic acid component is copolymerized, the melt viscosity of the copolyester is remarkably increased by the thickening action of the isophthalic acid component, and it becomes difficult to sufficiently increase the degree of polymerization.
Melt spinning of the copolyester obtained thereby becomes difficult. Therefore, in order to make the melt viscosity of the copolyester obtained by copolymerizing the isophthalic acid easily within the range where melt polymerization is possible and melt spinning is possible, it is necessary to stop the polymerization at a stage where the degree of polymerization is lower. As a result, the strength of the obtained copolyester fiber was lowered, and its use was significantly limited.

When the fiber made of the isophthalic acid component copolyester having the metal sulfonate group is used for ordinary clothing, it can be used although it is unsatisfactory in terms of strength and color vividness. However,
When the isophthalic acid copolyester is used as an ultrafine fiber, the spinning processability is poor and the commercial value is extremely reduced. In particular, in the field of sports, high tear strength is required. The ultrafine fibers made of the isophthalic acid component copolyester having a base had a practical problem. Therefore, an object of the present invention is a splittable conjugate fiber which is dyeable with a cationic dye and can be divided into ultrafine fibers which are excellent in mechanical properties, yarn formability, processability, unwinding property, dyeing fastness, feeling and the like. To provide.

[0006]

According to the present invention, the above-mentioned problem is a splittable conjugate fiber comprising an alkali hardly soluble component A and an alkali easily soluble component B, which is a polymer constituting the alkali hardly soluble component A. − Is a glass transition point depressant 1 to 5
This is achieved by providing a splittable conjugate fiber which is an aromatic polyester having a sulfonate group and containing 0.1% to 1% by weight of inorganic fine particles.

In the polymer constituting the poorly soluble component A of the present invention (hereinafter abbreviated as component A), the aromatic polyester having a sulfonate group is terephthalic acid as a main acid component and at least one kind of component is used. An aromatic polyester obtained from a glycol component and a polyester in which a dicarboxylic acid component having a sulfonate group is copolymerized in the polyester. As the glycol component, it is preferable to use at least one of ethylene glycol, trimethylene glycol and tetramethylene glycol. Particularly, the aromatic polyester is ethylene terephthalate unit and / or butylene. It is preferably composed mainly of terephthalate units. Of course, the aromatic polyester in the present invention,
If necessary, a terephthalic acid component, a dicarboxylic acid having a sulfonate group, and a copolymerization component other than the above-mentioned glycol may be contained within the range not impairing the mechanical properties of the polyester.

As the dicarboxylic acid component having a sulfonate group, 5-sodium sulfoisophthalic acid,
A dicarboxylic acid component having an alkali metal sulfonate such as 5-potassium sulfoisophthalic acid and 5-lithium sulfoisophthalic acid; a phosphonium sulfonate such as 5-tetrabutylphosphonium sulfoisophthalic acid and 5-ethyltributylphosphonium sulfoisophthalic acid. The dicarboxylic acid which it has can be mentioned. Among them, 5-sodium sulfoisophthalic acid is preferable in terms of reactivity and price. As for the dicarboxylic acid component having a sulfonate group, only one kind may be copolymerized in the aromatic polyester, or two or more kinds may be copolymerized.

The above-mentioned dicarboxylic acid component having a sulfonate group is 1.2 to 3 mol%, especially 1.5 to 2 with respect to the total dicarboxylic acid component constituting the aromatic polyester.
It is preferable that the copolymer is copolymerized at a ratio of mol%. When the proportion of the dicarboxylic acid component having a sulfonate group is less than 1.2 mol%, it is difficult to obtain a polyester fiber having a clear and good color tone when dyed with a cationic dye, and when it exceeds 3 mol%, Thickening of the polyester becomes remarkable and spinning becomes difficult, and the dyeing amount of the cationic dye becomes excessive and the vividness of the color tone is lost.

The above aromatic polyester can be synthesized by any method. For example, in the case of polyester mainly composed of polyethylene terephthalate units, a dicarboxylic acid component having a sulfonate group is used, and terephthalic acid and ethylene glycol are directly esterified or a lower alkyl terephthalic acid is used. A transesterification reaction between an ester and ethylene glycol or a reaction between terephthalic acid and ethylene oxide produces a glycol ester of terephthalic acid or an oligomer thereof, which is heated under reduced pressure. It can be produced by a usual synthetic method in which the polycondensation reaction is carried out until the desired degree of polymerization is reached. The dicarboxylic acid component having a sulfonate group may be added at any time as long as it can be introduced into the polyester as a polymerization component, and may be added to the polyester synthesis raw material or after the transesterification reaction and before the polymerization. Good.

The glass transition point depressant referred to in the present invention (hereinafter,
(Tg depressant is abbreviated) means that when 2% by weight of the Tg depressant is added to the aromatic polyester having a sulfonate group, the Tg of the aromatic polyester is higher than that when the Tg depressant is not added. An agent having a property of lowering by 2 ° C or more. Tg of aromatic polyester is DSC
It can be easily measured by the following methods. In the present invention, T
As the g-lowering agent, any agent having the above-mentioned conditions can be used, but the following general formula (I);

R ↑ 1O-X-R ↑ 2 (I) (wherein X is an aromatic residue, R ↑ 1 and R ↑ 2 are carbon atoms 6
To 18 alkyl groups or arylalkyl groups)
It is preferable to use at least one of the compounds represented by

In the compounds represented by the above general formula (I), preferable examples of the aromatic residue X include divalent groups represented by the following formulas (II) to (IX). it can.

[0014]

[Chemical 1]

[0015]

[Chemical 2]

[0016]

[Chemical 3]

[0017]

[Chemical 4]

[0018]

[Chemical 5]

[0019]

[Chemical 6]

[0020]

[Chemical 7]

[0021]

[Chemical 8]

And a Tg suitable for use in the present invention.
As specific examples of the depressant, for example, the following general formula (X) to
The compound represented by (XIII) can be mentioned.

[0023]

[Chemical 9]

[0024]

[Chemical 10]

[0025]

[Chemical 11]

[0026]

[Chemical 12]

The content of Tg depressant is in the range of 1 to 5% by weight, based on the weight of aromatic polyester. When the content of the Tg depressant is less than 1% by weight, the effect of adding the Tg depressant is not sufficiently exhibited and the splittable conjugate fiber is difficult to be produced. On the other hand, when the content of the Tg depressant exceeds 5% by weight, the aromatic polyester is colored and the dyeing fastness of the split fiber is lowered. Content of Tg depressant is 2 to 4% by weight
It is preferably in the range of.

The inorganic fine particles have an average particle size of 15 to
Inorganic fine particles of 70 mμ are preferred. If the average particle size of the inorganic fine particles is less than 15 mμ, drawn fluff and drawn unevenness are likely to occur, while if the average particle size exceeds 70 mμ, the split fibers are easily fibrillated. Inorganic particles are aluminum coat,
The surface thereof may be modified by introducing an alkyl group or the like. The refractive index of the inorganic fine particles is not particularly limited, but if it is desired to maintain the brilliant transparency of the split fibers, the refractive index is smaller than that of the aromatic polyester, i.e., 1.
It is preferable to use inorganic fine particles of 65 or less. While maintaining the transparent transparency of the aromatic polyester, the inorganic fine particles having a refractive index of 1.65 or less and the refractive index of 1.
It is also possible to use together with more than 65 inorganic fine particles. In the present invention, silica having a refractive index of 1.65 or less, alumina, kaolin, calcium carbonate and the like are preferable, and silica having an average particle diameter of 15 to 70 mμ is particularly preferable.

The content of the inorganic fine particles is in the range of 0.1 to 1% by weight based on the weight of the aromatic polyester. When the content of the inorganic fine particles is less than 0.1% by weight, good stretchability due to the synergistic effect with the Tg depressant is not exhibited. On the other hand, when the content of the inorganic fine particles exceeds 1% by weight, the strength of the splittable conjugate fiber, and thus the splittable fiber, is lowered. The content of the inorganic fine particles is preferably in the range of 0.3 to 0.5% by weight.

The timing and method of adding the Tg depressant and the inorganic fine particles to the aromatic polyester are not particularly limited. For example, the Tg depressant and the inorganic fine particles may be added simultaneously, sequentially, or at completely different times. The Tg depressant and the inorganic fine particles may be added before, during, or after the polymerization of the aromatic polyester at an appropriate time, or may be added as a master-batch in the polyester chip, or during melt spinning. You may add.

In the present invention, in order to obtain a split fiber having a strength of 3.8 g / denier or more, the intrinsic viscosity [η] of the aromatic polyester having a sulfonate group and the content (D) of the Tg lowering agent are ) (Wt%) preferably satisfies the following relational expression.

0.01 × D + 0.54 ≦ [η] ≦ 0.01 × D + 0.68 (where 1 ≦ D ≦ 5) In the above, the intrinsic viscosity [η] of the aromatic polyester is the aromatic polyester. It is a value when dissolved in a mixed solvent of phenol / tetrachloroethane (weight ratio 1: 1) and measured at 30 ° C., and the strength and elongation of the ultrafine fibers are J
It is a value when measured by IS L 1013.

When the intrinsic viscosity [η] of the aromatic polyester having a sulfonate group is smaller than 0.01 × D + 0.54, the degree of polymerization of the aromatic polyester is small, and thus a split fiber having sufficiently high strength can be obtained. May not be. On the other hand, when the intrinsic viscosity [η] of the aromatic polyester having a sulfonate group is larger than 0.01 × D + 0.68, the thickening action of the aromatic polyester may be too large and spinning as a composite fiber may be difficult. is there.

In the present invention, the polymer which constitutes the easily soluble component B (hereinafter abbreviated as component B) is not particularly limited as long as it is a polymer which is easily dissolved in alkali, but the alkali dissolution rate constitutes the component A. Polymer 5
It is preferably double or more, particularly preferably 7 or more. The alkali dissolution rate is a value measured by dissolving a polymer in an alkaline aqueous solution having a concentration of 40 g / liter at 98 ° C. When the alkali dissolution rate of component B is less than 5 times that of component A, when component B is removed from the composite fiber of the present invention with alkali, the removal is insufficient and sufficient splitting cannot be carried out, resulting in split fibers. The fineness and quality irregularities are likely to occur. Further, if the alkali dissolution time is lengthened in order to sufficiently remove the component B, the component A is dissolved and the quality of the split fibers, for example, the strength is deteriorated, which is not preferable.

As the component B, a polyester obtained from terephthalic acid as a main acid component and at least one glycol component such as ethylene glycol, trimethylene glycol, tetramethylene glycol or the like can be mentioned. To be As a method of increasing the alkali dissolution rate, a method of copolymerizing a dicarboxylic acid component having a sulfonate group such as 5-sodium sulfoisophthalic acid, 5-potassium sulfoisophthalic acid, 5-lithium sulfoisophthalic acid with the polyester, a molecular weight of 1,000 to A method of copolymerizing or mixing 20,000 polyalkylene glycols such as polyethylene glycol, polypropylene glycol, and polybutylene glycol with polyester, or copolymerizing polyoxyalkylene glycol with one end blocked with polyester. And the like.

The copolymerization amount of the above-mentioned dicarboxylic acid component having a sulfonate group is preferably in the range of 1.5 to 7.0 mol% with respect to the total dicarboxylic acid component constituting the polyester, and polyalkylene glycol is used. The copolymerization amount or mixture amount of the above and the copolymerization amount of the polyoxyalkylene glycol with one end blocked are preferably in the range of 0.5 to 20% by weight based on the weight of the polyester. In the present invention, a polyethylene terephthalate-based polyester obtained by copolymerizing a dicarboxylic acid component having a sulfonic acid group is copolymerized or mixed with polyoxyalkylene glycol, or a dicarboxylic acid component having a sulfonic acid group is copolymerized. It is preferable to use a polymerized polyethylene terephthalate polyester copolymerized with a polyoxyalkylene glycol having one end blocked.

In the splittable conjugate fiber of the present invention, it is necessary that the component A is split into two or more by the component B in the cross section orthogonal to the fiber axis (hereinafter referred to as the fiber cross section). For example, a cross section as shown in FIGS. 1 to 6. In the splittable conjugate fiber, the composite ratio (A / B: weight ratio) of component A and component B may be in the range of 1/1 to 4/1, particularly in the range of 1.5 / 1 to 4/1. It is preferable because it can be dissolved in an alkali industrially. However, if the amount of the component B is extremely reduced, the area of the component B in contact with the alkali is reduced, so that it takes a long time to remove the component B, and as a result, the component A is also dissolved in the alkali. It is preferable that A / B does not exceed 4/1.

In order to further enhance the color developability of the split fibers, the flatness of the cross section of the split fibers orthogonal to the fiber axis is preferably in the range of 1 to 8, particularly 1.2 to 4. The flatness is expressed by the long axis / short axis when the longest line segment is the longest line segment and the shortest line segment is the shortest line segment that passes through the center of gravity of the fiber cross section and connects two points on the outer circumference. It is a value. The color developability of the ultrafine fibers depends on the surface area of the single fiber, and the smaller the surface area, the better the color developability. If the surface area of the ultrafine fibers is extremely large, the ultrafine fibers are lightened or whitened due to diffused reflection of light, and the color developability tends to decrease. Therefore, as the flatness of the split fibers approaches 1, the color developability becomes better. However, if the flatness of the split fibers is less than 1, the color developability of the fibers is reduced and splitting is easier, and fibrillation tends to deteriorate processability, which is not preferable. On the other hand, if the flatness of the split fibers exceeds 8, the surface area of the fibers becomes large and the color developability of the fibers deteriorates. Furthermore, in order to achieve such flatness, the contact surface of each component in the splittable conjugate fiber must be increased,
It is not preferable because the resolvability by alkali deteriorates. However, when the flatness increases, the color developability of the fiber decreases, but since light is easily reflected, a glossy woven or knitted product can be obtained. In the present invention, the flatness of the split fiber can be selected according to the purpose of use and the application.

The splittable conjugate fiber of the present invention can be easily prepared by a usual melt conjugate spinning method, for example, a method in which polymer streams of the component A and the component B are discharged from different gear pumps and combined by using a special nozzle pack. The obtained spinning raw yarn can be drawn by a usual method. For example, by using a heating roller at a temperature higher than the higher glass transition temperature of the glass transition temperature of component A and the glass transition temperature of component B constituting the splittable conjugate fiber, a draw ratio corresponding to the spinning speed, For example, it can be stretched to 3.0 to 5.0 times and subsequently subjected to heat treatment. A method in which spinning and drawing is directly connected, such as spin drawing, may be used. The drawn yarn obtained is woven and knitted by a conventional method as at least a part of the cloth such as taffeta, satin, satin woven fabric, double woven fabric, broad weave, circular knitting, vertical knitting, pile knitting, and the like, and then an alkaline aqueous solution. The component B is completely removed in step 1 to obtain a fabric made of ultrafine fibers containing only the component A, which is dyed and finished before being commercialized.

When the cloth made of the above-mentioned splittable conjugate fiber is treated with alkali, the removal rate of component B, that is, the alkali reduction rate of the splittable conjugate fiber is reduced by 3% by weight or more more than the composite ratio of component B. It is preferable. Although the detailed reason for this is not clear, particularly when the component A and the component B are polyesters, a reaction such as transesterification occurs at the interface between the component A and the component B, which requires a large amount of weight reduction. It is also thought to be the cause. The alkali concentration at the time of alkali treatment is preferably 5 to 100 g / liter,
The temperature is preferably 60 ° C to the boiling point.

The cloth composed of the split fibers divided by the alkali treatment is subsequently dyed with a cationic dye. As the dye, a generally used cationic dye is used, which is dyed by a normal atmospheric dyeing method and subjected to post-processing to obtain a product.
The above dyeing method includes a beam method, a winch method, a drum method, a circular method, etc., but in order to make the division by the alkali treatment more complete, the winch method or the sawing method or the winch method is added. The curular method is preferred. In particular, when the component A and the component B are split type conjugate fibers of the same polyester, the split fibers are partially stuck even after splitting with an alkali, so this method is preferable.

Although the split fibers obtained by subjecting the splittable conjugate fiber of the present invention to alkali treatment are fibers having a small fiber fineness of 0.1 to 0.5 denier, depending on the flatness, they may be brie. Tissue sharpness and strength 3.8g / denier
High strength of more than 1g, or gloss and strength of 3.8g
Since it has a high strength of denier or more, it is suitable for use in the fields of sports clothing, various optical devices, cleaning cloth for lenses, high-grade fashion clothing and the like.

[0043]

EXAMPLES The present invention will now be described in detail with reference to examples, but the present invention is not limited thereto. Each physical property in the examples was measured by the following methods. (1) Intrinsic viscosity [η] It is a value measured at 30 ° C. by dissolving it in a mixed solvent of phenol / tetrachloroethane (weight ratio 1: 1). (2) Alkali dissolution rate ratio: Measured by dissolving a polymer in an alkaline aqueous solution having a concentration of 40 g / liter at 98 ° C., and showing the value of component B when the alkali dissolution rate of component A is 1. (3) Strength (g / denier) and elongation (%) of split fibers These are values measured according to JIS L 1013. (4) Flatness of split fiber The flatness of the split fiber was measured and calculated from a cross-sectional photograph of the fiber.

Example 1 Dimethyl terephthalate containing 1.7 mol% of dimethyl 5-sodium sulfoisophthalate (hereinafter abbreviated as SIP) as a dicarboxylic acid component and ethylene glycol were used to conduct an ester exchange method. Polymerization was performed according to a conventional method to produce a polyester having an intrinsic viscosity [η] = 0.67. At that time, 3% by weight of a Tg depressant represented by the general formula (X) and 0.3% by weight of silica having an average particle diameter of 30 mμ and a refractive index of 1.55 were added in the latter stage of polymerization after transesterification ( Ingredient A). Also, SIP is 5.0 mol%
Containing dimethyl terephthalate and ethylene glyco-
Polymerization was carried out according to the transesterification method using a polymer, and 3 wt% of polyethylene glycol having a molecular weight of 11,000 was added to the obtained polymer and kneaded to obtain an intrinsic viscosity [η] = 0.
49 polyesters were obtained (component B). Ingredient A and ingredient B
And were spun at a spinneret temperature of 305 ° C. and a take-up speed of 1000 m / min using a composite spinning machine to produce 255 denier / 48 filaments, and 11 filament layer composite yarns (composite ratio A / B = 3/1) was produced. Then, the obtained spun raw yarn was drawn at a draw ratio of 3.4 using a heating roller at a temperature of 75 ° C. and then heat-treated at a temperature of 130 ° C. to obtain a drawn yarn of 75 denier / 48 filaments. Was manufactured. The strength and elongation of this drawn yarn were 4.8 g / denier and 28%. The spinning processability and the drawing processability were both good.

Using this drawn yarn, a 2/2 twill (180 warps / inch, weft 110 threads / inch) was produced, and 9
When the sample was dipped in an aqueous sodium hydroxide solution having a concentration of 40 g / liter at 8 ° C. for 12 minutes for alkali treatment, the alkali weight loss rate was 25%. Since the division was insufficient, alkali treatment was applied for another 3 minutes to reduce the weight loss rate to 2
At 8%, the division was almost complete. The flatness of the split fibers after splitting was 4.5, and the strength and the elongation were 4.3 g / denier and 28%, respectively. The cloth made of the divided fibers thus obtained was subjected to usual scouring and presetting, and then dyed under the following dyeing conditions. As a result, it had a touch peculiar to the ultrafine fibers and was dyed in bright red. Table 3 shows the physical properties of the final product. Windbreaker
It was suitable as a raw material.

Dyeing conditions for cloth Cation dyeing bath composition: Cathilon Brill Red 4GH 2% owf (manufactured by Hodogaya Chemical Co., Ltd.) Sodium sulfate 3 g / liter Acetic acid 1% owf Sodium acetate 0.5% owf ETA 0.1 g / liter Bath ratio: 1:50 Dyeing temperature: 98 ℃ Dyeing time: 40 minutes

Comparative Example 1 Spinning, drawing, twill finishing, alkali treatment and dyeing were carried out in the same manner as in Example 1 except that as the component A, a polymer containing no Tg depressant and no silica was used. The results are shown in Tables 2 and 3. The spinning processability and the drawing processability were both poor, and there were spots of dyeing and color development was low, and the product had no commercial value.

Comparative Examples 2 to 3 As a component A, a polymer not containing a Tg lowering agent was used (Comparative Example 2), but as the component A, a Tg lowering agent was not added and an intrinsic viscosity [η] = 0.55. Spinning, stretching, twill finishing, alkali treatment and dyeing were performed in exactly the same manner as in Example 1 except that the above polymer (Comparative Example 3) was used. The results are shown in Tables 2 and 3. All of them had low fiber strength and had uneven dyeing.

Example 2 Spinning, drawing, twill finishing, alkali treatment and dyeing were carried out in the same manner as in Example 1 except that the SIP content in the component A was 2.5 mol%. The results are shown in Tables 2 and 3. The spinnability and drawability are good, and the fiber fineness after alkali treatment is 0.25 denier,
The strength was 4.1 g / denier and the elongation was 30%. The color development was also good, and it was bulky and had a good touch.

Comparative Example 4 Spinning, drawing, twill finishing, alkali treatment and dyeing were performed in the same manner as in Example 2 except that a polymer having an intrinsic viscosity [η] = 0.73 was used as the component A. .
The results are shown in Tables 2 and 3. Since the intrinsic viscosity is high, the spinning and drawing process was poor due to the thickening effect, and the quality was uneven.

Example 3 In the component A, spinning, drawing and stretching were carried out in the same manner as in Example 1 except that the kind of the Tg depressant was set to the general formula (XI) and the intrinsic viscosity [η] was set to 0.65. Twill finish, alkali treatment and dyeing were performed. The results are shown in Tables 2 and 3. The spinning processability and drawing processability are also good,
The dyed fabric was vivid in color and reached an acceptable level.

Comparative Example 5 In Component A, spinning, drawing, twill finishing, alkali treatment and dyeing were performed in the same manner as in Example 3 except that a polymer to which silica was not added was used. The results are shown in Tables 2 and 3. The spinning processability was good,
In the drawing process, fluff and single yarn breakage frequently occurred, and good drawn yarn could not be obtained.

Comparative Example 6 In Component B, spinning, drawing, twill finishing, alkali treatment and dyeing were carried out in the same manner as in Example 1 except that a polymer to which polyethylene glycol was not added was used. The results are shown in Tables 2 and 3. The spinning processability and the drawing processability were very poor, the alkali solubility was also poor, and the splitting was insufficient, so that split fibers (ultrafine fibers) could not be obtained.

Example 4 The drawn yarn obtained in Example 1 was overheated using a spindle false twisting machine so that the false twist number was 3360 t / m and the tension on the spindle entering side was about 20 g. The false twisting rate was adjusted and false twisting was performed at a false twisting temperature of 180 ° C. A knitted fabric is produced by a tubular knitting machine using the obtained false twist textured yarn,
When this was treated with alkali to reduce the weight loss rate to 27.5%, it was divided into ultrafine fibers and had good feeling and physical properties. The knitted fabric after dyeing had a vivid color.

Example 5 As the component B, 2.0 mol% of SIP was contained and the molecular weight was 6
Spinning, drawing, twill finishing, alkali treatment and dyeing were carried out in the same manner as in Example 1 except that a polymer having an intrinsic viscosity [η] = 0.49 in which 6% by weight of polyethylene glycol of 6% was added and kneaded. went. The results are shown in Table 2.
And shown in Table 3. The spinning processability, the drawing processability and the quality were good, and the color development of the dyed fabric was also good.

Comparative Example 7 As component B, SIP was contained in an amount of 3.0 mol%, and the molecular weight was 1
Spinning, stretching, twill finishing, alkali treatment and dyeing were performed in the same manner as in Example 1 except that a polymer obtained by adding and kneading 1000% of polyethylene glycol by 25% by weight was used. Since the amount of polyethylene glycol added in component B was too large, strand cutting was difficult, quality unevenness occurred, and the product had no commercial value.

Comparative Example 8 Spinning, drawing, twill finishing, alkali treatment and dyeing were conducted in the same manner as in Example 1 except that polyethylene terephthalate having an intrinsic viscosity [η] = 0.68 was used as the component A. went. The spinning process property and the drawing process property were good, and the yarn quality and the texture of the fabric were also good, but the dyeability with the cationic dye was poor, and the dye had to be dyed with the disperse dye,
No clear color tone was seen.

Examples 6 to 7 Example 1 was repeated except that the fiber cross-sectional shape was as shown in FIG. 4 (Example 6) and the composite ratio of component A and component B was 1/1 (Example 7). The spinning, drawing, twill finishing, alkali treatment and dyeing were performed in exactly the same manner as in. Similar to the fabric obtained in Example 1, the yarn had high strength and elongation, and had good color developability. The gloss was also good.

Comparative Examples 9 to 10 The composite ratio of Component A and Component B was 1/2 (Comparative Example 9), 5 /
Spinning, stretching, twill finishing, alkali treatment and dyeing were performed in exactly the same manner as in Example 1 except that No. 1 (Comparative Example 10) was used. Since the fabric obtained in Comparative Example 9 has a small amount of component A, the yarn strength is low and the drawability is poor. Further, the fabric obtained in Comparative Example 10 was not sufficiently divided by the alkali treatment, and thus ultrafine fibers could not be obtained. When the alkali treatment time was lengthened in order to perform sufficient division,
The component A was also attacked by the alkali, and the strength of the cloth was extremely reduced.

Example 8 As the component B, 2.5 mol% of SIP was contained and the molecular weight was 2
6,000 polyoxyethylene glycol-methyl-glycidyl ether copolymerized by 16% by weight, except that a polyester polymer having an intrinsic viscosity [η] = 0.72 was used, and spinning was carried out in the same manner as in Example 1, Stretching, twill finishing, alkali treatment and dyeing were performed. The obtained fabric was good in both quality and color development.

Example 9 As the component B, 5.0 mol% of SIP was contained and the molecular weight was 2
A polyester polymer having an intrinsic viscosity [η] = 0.49 obtained by copolymerizing 000 single-end-blocked polyoxyethylene glycols in an amount of 16% by weight was used.
Except in the same manner as in Example 1, spinning, drawing,
Twill finish, alkali treatment and dyeing were performed. The obtained cloth had good quality and extremely good color development.

Example 10 Spinning, drawing, twill finishing, alkali treatment and dyeing were performed in the same manner as in Example 9 except that the fiber cross-sectional shape was as shown in FIG. The resolution was good, and the color development was also very good. In addition, the fiber quality was at an acceptable level. A fabric having a soft and swelling texture was obtained.

Examples 11 to 12 Except that the fiber cross-sectional shape is as shown in FIG. 2 (Example 1
1) and 9th Embodiment except that as shown in FIG. 6 (12th Embodiment)
The spinning, drawing, twill finishing, alkali treatment and dyeing were performed in exactly the same manner as in. Perhaps because the flatness was a little too large, the splittability was slightly inferior, and although the obtained fabric had a little lack of flexibility, there was no problem in practical use. Example 1
Since the split fiber obtained in No. 2 had a large flatness of 10, the coloring property was slightly inferior, but the glossiness was excellent and the british characteristic was exhibited.

Comparative Example 11 Spinning, stretching, twill finishing, alkali treatment and dyeing were carried out in the same manner as in Example 9 except that PET was used as the component A. Although the texture of the cloth was good, the color development was very poor and it did not look good at all.

[0065]

[Table 1]

[0066]

[Table 2]

[0067]

[Table 3]

[0068]

According to the present invention, an aromatic polyester having a specific ratio of a sulfonate group and a specific intrinsic viscosity is contained as an alkali hardly soluble component in a specific amount containing a glass transition point depressant and inorganic fine particles. By using this polymer, ultrafine fibers can be obtained using a polymer having a high intrinsic viscosity, and dyeing with a cationic dye is possible. Further, since it is possible to dye with a cationic dye, a fabric containing the ultrafine fibers is excellent in color developability, color tone sharpness, etc., and a very high quality product can be obtained.

[Brief description of drawings]

FIG. 1 shows an example of a fiber cross section of a splittable conjugate fiber of the present invention.

FIG. 2 shows another example of the fiber cross section of the splittable conjugate fiber of the present invention.

FIG. 3 shows another example of the fiber cross section of the splittable conjugate fiber of the present invention.

FIG. 4 shows another example of the fiber cross section of the splittable conjugate fiber of the present invention.

FIG. 5 shows another example of the fiber cross section of the splittable conjugate fiber of the present invention.

FIG. 6 shows another example of the fiber cross section of the splittable conjugate fiber of the present invention.

[Explanation of symbols]

 A: Component A is shown. B: Component B is shown.

Front page continuation (72) Inventor Takao Akagi 1621 Sakata, Kurashiki, Okayama Prefecture Kuraray Co., Ltd.

Claims (2)

[Claims] 1. A splittable conjugate fiber comprising an alkali hardly soluble component A and an alkali easily soluble component B, wherein the polymer constituting the alkali hardly soluble component A contains 1 to 5% by weight of a glass transition point depressant. A splittable conjugate fiber which is an aromatic polyester having a sulfonate group containing 0.1 to 1% by weight of inorganic fine particles. 2. The splittable conjugate fiber according to claim 1, wherein the flatness of the cross section of the split fiber orthogonal to the fiber axis is in the range of 1 to 8.