JPH05272012A - Production of cation-dyeable polyester ultrafine fiber - Google Patents

Abstract

PURPOSE:To obtain a method for producing ultrafine fiber composed of a cation- dyeable polyester excellent in mechanical characteristics, brightness of a dye, fiber manufacturing properties, etc. CONSTITUTION:An aromatic polyester prepared by including 1-5wt.% glass transition point lowering agent and 0.1-1.0wt.% solid fine particles in an aromatic polyester having 1.2-2.0mol% copolymerization ratio of a dicarboxylic acid component having sulfonate group is spun at a speed as high as >=3000m/min under specific spinning temperature conditions to afford the objective ultrafine fiber having <=1 denier average size.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a polyester dyeable polyester ultrafine fiber. More specifically, the present invention relates to a method for producing a polyester ultrafine fiber which is dyeable with a cationic dye and is excellent in physical properties such as mechanical properties, spinnability and feel.

[0002]

2. Description of the Related Art Polyester fiber has high strength, is chemically stable, and has dimensional stability, pleat retention,
Since it is excellent in wrinkle resistance and has various good properties, it is widely used for clothing and industrial materials. However, as is well known, the polyester fiber is inferior in dyeability, and it is difficult to dye with a dye other than the disperse dye.

Therefore, various methods for improving the dyeability of polyester fibers have been proposed. As one of them, 5-
Conventionally, a method has been known in which an isophthalic acid component having a sulfonic acid metal base such as sodium sulfoisophthalic acid is copolymerized with polyester to enable dyeing with a cationic dye (for example, Japanese Patent Publication No. 34-10497).

It is also known to reduce the single yarn fineness in order to impart a unique soft texture to a woven or knitted product made of polyester fibers. In this case, 2000-40
Single yarn fineness of 0.1 by utilizing high-speed spinning at 00m / min.
1.0 denier ultrafine fibers are produced.

However, the polyester obtained by copolymerizing the above-mentioned isophthalic acid component having a sulfonic acid metal base has a large thickening effect during the polymerization reaction of the isophthalic acid component having a sulfonic acid metal base, and thus the polyester The viscosity of the polymerization system remarkably increases before the degree of polymerization of the polymer becomes sufficiently high, and the degree of polymerization cannot be sufficiently increased. Therefore, it is difficult to melt-spin the resulting polyester copolymer, and especially when an ultrafine fiber having a single yarn fineness of 0.1 to 1.0 denier is produced using high-speed spinning, the spinnability is It is extremely bad, and single yarn breakage occurs frequently during spinning to make spinning impossible, or even if spinning is possible, the obtained yarn has remarkably low mechanical properties and cannot be used.

In high-speed spinning of polyester, a method of cooling by adjusting the atmospheric temperature in the vicinity of the spun yarn has been proposed as a method for improving spinning defects such as breakage of fibers (for example, JP-A-56-140116). Japanese Patent Laid-Open No. Sho 61
-47817).

However, according to a follow-up test conducted by the present inventors, this method is effective for polymers having a polymerization degree suitable for fiber formation, but isophthalic acid having a sulfonate metal base having a large thickening action is used. It is not always an effective means for polyester copolymerized with the components, and in the case where the degree of polymerization of the copolymerized polyester is increased in order to obtain high-strength fiber, spinning is not possible.

As another means for making a polyester dyeable with a cationic dye, there is known a method in which an isophthalic acid component having a phosphonium sulfonate group is copolymerized with the polyester (for example, Japanese Patent Publication No. 47-22334). A method for producing ultrafine fibers made of copolyester has also been proposed (Japanese Patent Laid-Open No. 63-212322).

However, in this method, spinning defects due to the thickening action peculiar to polyester obtained by copolymerizing an isophthalic acid component having a sulfonic acid metal base are eliminated, but the heat resistance of the isophthalic acid component having a phosphonium sulfonate base is eliminated. However, since it is inferior to the isophthalic acid component having a metal sulfonate group, there is a drawback that the strength of the fiber is remarkably reduced in the steps such as heat setting and dyeing.

[0010]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a method for producing a polyester ultrafine fiber which is dyeable with a cationic dye and is excellent in mechanical properties, spinnability, sharpness and the like. is there.

[0011]

As a result of the study by the present inventors, a conventional polyester obtained by copolymerizing an isophthalic acid component having a metal sulfonate group is allowed to contain both a glass transition point depressant and solid fine particles. It was found that the spinnability of polyester is remarkably improved by their synergistic effect, and that high-quality cationic dye-dyeable ultrafine fibers can be obtained by spinning under specific spinning conditions. is there.

That is, according to the present invention, an aromatic polyester having a sulfonate group, which contains 1 to 5% by weight of a glass transition point depressant and 0.1 to 1.0% by weight of solid fine particles, is used at 3000 m / min. When a fiber having an average fineness of a single yarn of 1 denier or less is melt-spun at the above take-up speed, melt spinning is performed under conditions satisfying the following expressions and Is a method for producing a superfine polyester fiber.

[Equation 3] T ↓ H-T ↓ N <20

[Equation 4] 250 ≤ T ↓ A <T ↓ H [where T ↓ H is the spinning temperature (° C), T ↓ N is the spinning nozzle temperature (° C), and T ↓ A is 30 cm from directly below the spinning nozzle.
Ambient temperature within the range (℃)]

The "aromatic polyester having a sulfonate group" in the present invention is an aromatic polyester obtained from an acid component mainly comprising terephthalic acid and at least one glycol component, and the polyester. A polyester in which a dicarboxylic acid component having a sulfonate group is copolymerized. As the glycol component, it is preferable to use at least one kind of ethylene glycol, trimethylene glycol and tetramethylene glycol, and particularly the aromatic polyester is mainly ethylene terephthalate unit and / or Alternatively, those comprising a butylene terephthalate unit are preferred.

The aromatic polyester in the present invention may optionally contain a terephthalic acid component, a dicarboxylic acid component having a sulfonate group, and a copolymerization component other than the glycol component. The proportion of the other copolymerization component is usually desirably not more than about 10 mol% of the total dicarboxylic acid component.

Examples of the dicarboxylic acid component having a sulfonate group to be copolymerized with an aromatic polyester include 5-sodium sulfoisophthalic acid, 5-potassium sulfoisophthalic acid, 5-lithium sulfoisophthalic acid and other isophthalic acid having a sulfonate metal base. Examples thereof include 5-tetrabutylphosphonium sulfoisophthalic acid and isophthalic acid having a phosphonium sulfonate such as 5-ethyltributylphosphonium sulfoisophthalic acid. Of these, 5-sodium sulfoisophthalic acid is preferable. As for the dicarboxylic acid component having a sulfonate group, only one kind may be copolymerized with the aromatic polyester, or two or more kinds may be copolymerized.

The copolymerization ratio of the dicarboxylic acid component having a sulfonate group to the aromatic polyester is 1.2 to all the carboxylic acid components constituting the aromatic polyester.
It is preferably 2.0 mol%. When the copolymerization ratio of the dicarboxylic acid component having a sulfonate group is less than 1.2 mol%, a cationic dye-dyeable polyester fiber having a clear and good color tone when dyed with a cationic dye cannot be obtained. On the other hand, when the copolymerization ratio of the dicarboxylic acid component having a sulfonate group exceeds 2.0 mol%, the viscosity of the polyester is remarkably increased and spinning becomes difficult, and moreover, the dyeing seat of the cationic dye is increased to the fiber. The amount of cationic dye dyed becomes excessive and the sharpness of color tone is rather lost. From the viewpoint of the sharpness and spinnability of the dyed product, the copolymerization ratio of the dicarboxylic acid component having a sulfonate group is more preferably 1.5 to 1.7 mol%.

The above aromatic polyester can be synthesized by any method. For example, ethylene terephthalate
In the case of a polyester mainly containing a terephthalic acid unit, a dicarboxylic acid component having a sulfonate group is used as one component to directly esterify terephthalic acid and ethylene glycol, or a lower alkyl ester of terephthalic acid and ethylene glycol By transesterification with ethylene or by reacting terephthalic acid with ethylene oxide,
It can be produced by a usual synthetic method in which a glycol ester of terephthalic acid and / or a low polymer thereof is produced, and the polycondensation reaction is carried out by heating it under reduced pressure until a desired degree of polymerization is obtained.

In the present invention, 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 copolymerization component,
For example, it may be added to the synthetic raw material of polyester or after the transesterification and before the polymerization.

In the present invention, it is necessary that the aromatic polyester having a sulfonate group constituting the fiber contains a glass transition point depressant (hereinafter referred to as Tg depressant) and solid fine particles. By adding a Tg depressant and solid fine particles to an aromatic polyester having a sulfonate group, the spinnability of the polyester is remarkably improved.

The Tg lowering agent in the present invention is a Tg lowering agent in an aromatic polyester having a sulfonate group.
It means an additive having the property of lowering the glass transition temperature of the polyester by 2 ° C. or more when added by weight% as compared with the case where no Tg lowering agent is added. The glass transition temperature of the aromatic polyester at that time can be easily measured by a differential scanning calorimeter or the like. In the present invention,
As the Tg lowering agent, any one can be used as long as it can lower the glass transition temperature of the aromatic polyester having a sulfonate group by 2 ° C. or more when 2% by weight thereof is added. Formula (I);

[0021]

[Image Omitted] R ↓ 1 O—X—OR ↓ 2 (I) (wherein X is an aromatic group, R ↓ 1 and R ↓ 2 have 6 carbon atoms.
~ 18 alkyl groups or arylalkyl groups)
It is preferable to use at least one of the compounds represented by

In the compound represented by the above general formula (I), a preferable example of the aromatic group X is the following formula (I
The divalent group represented by I)-(IX) can be mentioned.

[0023]

[Chemical 3]

[0024]

[Chemical 4]

[0025]

[Chemical 5]

[0026]

[Chemical 6]

[0027]

[Chemical 7]

[0028]

[Chemical 8]

[0029]

[Chemical 9]

[0030]

[Chemical 10]

And a Tg suitable for use in the present invention.
Specific examples of the depressant include, for example, the general formula (X) shown below.
To (XIII) can be mentioned.

[0032]

[Chemical 11]

[0033]

[Chemical 12]

[0034]

[Chemical 13]

[0035]

[Chemical 14]

The content of the Tg depressant is in the range of 1 to 5% by weight based on the weight of the aromatic polyester having a sulfonate group. When the content of the Tg depressant is less than 1% by weight, the effect of improving the spinnability is not exhibited, and when it exceeds 5% by weight, the polyester is colored or the dyeing fastness is lowered. It is preferable that the content of the Tg lowering agent is 2 to 4% by weight.

The solid fine particles have an average particle size of 1
Inorganic fine particles of 5 to 70 mμ are preferred. When the particle diameter of the solid fine particles is less than 15 mμ, the frictional durability of the obtained fiber is insufficient, and when it exceeds 70 mμ, the fibers are easily fibrillated, which is not preferable. Solid fine particles are aluminum coat,
The surface may be modified by introducing an alkyl group or the like.
The refractive index of the solid fine particles is not particularly limited, but if it is desired to maintain the brittle transparency of the fiber, it is preferable to use solid fine particles having a refractive index of 1.65 or less, which is smaller than the refractive index of the aromatic polyester. .. It is also possible to use solid fine particles having a refractive index of 1.65 or less and solid fine particles having a refractive index of more than 1.65 in combination while maintaining the brittle transparency of the fiber. Examples of the solid fine particles used in the present invention include silica having a refractive index of 1.65 or less, alumina, kaolin, calcium carbonate, titanium oxide and the like. In particular, in order to achieve the transparency of the fiber and the sharpness peculiar to the cationic dye, the average particle diameter is 15 to 70 mμ and the refractive index is 1.65.
The following silicas are preferred.

The content of the solid fine particles is 0.1 to the weight of the aromatic polyester having a sulfonate group.
It is in the range of 1.0% by weight. The content of solid fine particles is 0.
If it is less than 1% by weight, good spinnability due to the synergistic effect with the Tg depressant is not exhibited, and if it exceeds 1.0% by weight, the effect of improving spinnability is rather deteriorated. The content of the solid fine particles is preferably 0.3 to 0.5% by weight.

The timing and method of adding the Tg depressant and the solid fine particles to the aromatic polyester having a sulfonate group are not particularly limited. For example, the Tg-lowering agent and the solid fine particles may be added at the same time or at completely different times. Further, the Tg depressant and the solid fine particles may be added at an appropriate time before or after the polymerization of the aromatic polyester having a sulfonate group, or may be added at the time of melt spinning.

In the present invention, it is preferable that the aromatic polyester having a sulfonate group containing a Tg lowering agent has an intrinsic viscosity [η] of 0.5 or more. When the intrinsic viscosity is less than 0.5, the mechanical properties of the obtained fiber, especially strength are insufficient, which is not preferable. Intrinsic viscosity [η] is 0.6
The above is more preferable. The intrinsic viscosity [η] of the aromatic polyester is the phenol / phenol of the aromatic polyester.
It is a value when dissolved in a mixed solvent of tetrachloroethane (weight ratio 1: 1) and measured at 30 ° C.

In the present invention, the above-mentioned aromatic polyester is melt-spun at a take-up speed of 3000 m / min or more so that the average fineness of a single yarn is 1 denier or less, preferably 0.8 denier or less, More preferably, fibers having a denier of 0.6 or less can be obtained. Even when the same aromatic polyester is melt-spun at a take-up speed of less than 3000 m / min,
A fiber having an average fineness of a single yarn of 1 denier or less cannot be obtained.
The average fineness of the single yarn in the present invention means the fineness of the unstretched fiber. The conventional cationic dye-dyeable polyester is extremely inferior in spinnability, and it has not been possible to obtain filaments having an average fineness of 1 denier or less.

In the present invention, the strength of the ultrafine fibers obtained is 3.5 g / denier or more, particularly 4.0 g / denier or more, and the strength of the fibers obtained from the conventional cationic dyeable polyester is 2. 5 ~ 3.5g / denier
Significant improvement can be seen and the application can be easily developed.

The above aromatic polyester is added to 3000 m /
During melt spinning at a take-up speed of not less than a minute, spinning is performed so as to satisfy the following expressions and.

[0044]

[Equation 5] T ↓ H-T ↓ N <20

[Equation 6] 250 ≤ T ↓ A <T ↓ H [where T ↓ H is the spinning temperature (° C), T ↓ N is the spinning nozzle temperature (° C), and T ↓ A is 30 cm from directly below the spinning nozzle.
Ambient temperature (℃)]

The difference between the spinning temperature and the spinning nozzle temperature is 20.
When the temperature is higher than 0 ° C, the unstretched fibers discharged from the spinning nozzle are pre-oriented, and the spinnability is reduced. The temperature difference is 1
It is preferably less than 5 ° C., particularly the spinning temperature and the spinning nozzle temperature are the same.

If the atmospheric temperature within the range of 30 cm from just below the spinning nozzle is lower than the lower limit of the above relational expression,
The unstretched fibers discharged from the spinning nozzle are pre-oriented, and the spinnability is reduced. As a means for maintaining the ambient temperature, for example, a heating unit of a cylindrical type, a flat plate type or the like may be provided. If the section for controlling the atmospheric temperature exceeds 30 cm, the degree of polymerization of the fiber during spinning will be greatly reduced, and the spinnability will be problematic. A preferable section is within 20 cm from immediately below the spinning nozzle.

Here, the spinning temperature (T ↓ H) is the temperature of the spinning head portion, and the spinning nozzle temperature (T ↓ N) is the surface temperature of the spinning nozzle. In addition, 3 from directly below the spinning nozzle
The atmospheric temperature (T ↓ A) within the range of 0 cm is a value measured by a thermocouple at a position 10 mm away from the outer circumference of the traveling fiber bundle.

The fibers thus obtained can be subjected to drawing, heat treatment, false twisting, etc., if necessary.

[0049]

In the present invention, the mechanism by which ultrafine fibers can be produced from an aromatic polyester having a sulfonate group such as sodium sulfoisophthalate is not clear, but
It is estimated as follows. That is, since the Tg depressant is dispersed in the polyester molecular chains and suppresses ionic bonds between the molecular chains, the mobility of the polyester molecular chains is improved and the spinnability is remarkably improved. However, only the action of the Tg depressant does not always enable high-speed melt spinning. However, when the solid fine particles are contained in the fiber together with the Tg depressant, unexpectedly, the spinnability is remarkably improved,
It became possible to manufacture ultrafine fibers at high speed.

Further, since the Tg depressant has a function of suppressing the ionic bond between the molecular chains of the polyester, there is little thickening of the aromatic polyester having a sulfonate group, and the conventional cationic dye-dyeable polyester can be used. In comparison, the intrinsic viscosity can be increased and spinning can be performed. Therefore,
For example, ultrafine fibers having excellent mechanical properties such as strength and tear strength can be obtained. The ultrafine fibers thus obtained can be suitably used in the field of sports clothing and the like.

[0051]

EXAMPLES The present invention will now be described in detail with reference to examples, but the present invention is not limited thereto. In the examples, the intrinsic viscosity [η] of the aromatic polyester is, as described above, phenol / tetrachloroethane (weight ratio 1:
It is a value when dissolved in the mixed solvent of 1) and measured at 30 ° C., and the strength of the obtained ultrafine fiber is JIS L 1013.
It is the value measured according to.

Example 1 As a dicarboxylic acid component, dimethyl terephthalate containing 1.7 mol% of dimethyl 5-sodium sulfoisophthalate (hereinafter abbreviated as SIP) and ethylene glycol were used to conduct an ester exchange method. Polymerization was carried out according to a conventional method to produce a polyester having an intrinsic viscosity [η] of 0.63. At that time, 2% by weight of a Tg depressant represented by the general formula (XII) and 0.3% of silica having an average particle diameter of 30 mμ and a refractive index of 1.55 were used in the latter stage of polymerization after transesterification.
Wt% was added. Using the obtained polyester chips, a spinning temperature of 305 ° C., a spinning nozzle temperature of 293 ° C., and a range of 30 cm from directly under the spinning nozzle were set by a cylindrical heating unit.
It was kept at 00 ° C. and melt-spun by a conventional method at a take-up speed of 4000 m / min to obtain an ultrafine fiber of 36 denier / 72 filaments. Table 1 shows the spinning state and the strength of the obtained fiber.

Example 2 A polyester having an intrinsic viscosity [η] of 0.63 was produced in the same manner as in Example 1 except that the Tg depressant represented by the general formula (XI) was used. Spinning was performed under the same spinning conditions as in Example 1 to obtain ultrafine fibers of 36 denier / 72 filaments. Table 1 shows the spinning state and the strength of the obtained fiber.

Example 3 Intrinsic viscosity [η] was 0.60 in the same manner as in Example 1 except that the Tg depressant represented by the general formula (XIII) was used.
Of polyester was produced. Spinning was performed under the same spinning conditions as in Example 1 to obtain ultrafine fibers of 36 denier / 72 filaments. Table 1 shows the spinning state and the strength of the obtained fiber.

Comparative Example 1 A polyester having an intrinsic viscosity [η] of 0.60 was produced in the same manner as in Example 1 except that the Tg depressant and solid fine particles were not added. Spinning under the same spinning conditions as in Example 1,
Ultra fine fibers of 36 denier / 72 filaments were obtained. Table 1 shows the spinning state and the strength of the obtained fiber.

Comparative Example 2 In the same manner as in Example 1 except that the Tg depressant was not added,
A polyester having an intrinsic viscosity [η] of 0.53 was produced.
Spinning was performed under the same spinning conditions as in Example 1, and 36 denier / 7
Two filament ultrafine fibers were obtained. Table 1 shows the spinning state and the strength of the obtained fiber.

Comparative Example 3 In the same manner as in Example 1 except that solid fine particles were not added,
A polyester having an intrinsic viscosity [η] of 0.55 was produced.
Spinning was performed under the same spinning conditions as in Example 1, and 36 denier / 7
Two filament ultrafine fibers were obtained. Table 1 shows the spinning state and the strength of the obtained fiber.

Comparative Example 4 In the same manner as in Example 1, a polyester copolymerized with SIP and having an intrinsic viscosity [η] of 0.60 was produced. Using the obtained polyester chips, a spinning temperature of 305 ° C.,
Spinning nozzle temperature 280 ° C, 30 cm from directly below the spinning nozzle
The above range was maintained at 280 ° C. by the cylindrical heating part, and melt spinning was carried out by a conventional method at a take-up speed of 3000 m / min to obtain an ultrafine fiber of 36 denier / 72 filaments. Table 1 shows the spinning state and the strength of the obtained fiber.

Comparative Example 5 In the same manner as in Example 1, a polyester copolymerized with SIP and having an intrinsic viscosity [η] of 0.63 was produced. Using the obtained polyester chips, a spinning temperature of 305 ° C.,
Melt spinning was carried out by a conventional method at a spinning nozzle temperature of 280 ° C. and a take-up speed of 3000 m / min to obtain ultrafine fibers of 36 denier / 72 filaments. Table 1 shows the spinning state and the strength of the obtained fiber.

Comparative Example 6 In the same manner as in Example 1, a polyester copolymerized with SIP and having an intrinsic viscosity [η] of 0.63 was produced. Using the obtained polyester chips, a spinning temperature of 305 ° C.,
Melt-spinning was carried out by a conventional method at a spinning nozzle temperature of 293 ° C. and a take-up speed of 3000 m / min to obtain ultrafine fibers of 36 denier / 72 filaments. Table 1 shows the spinning state and the strength of the obtained fiber.

[0061]

[Table 1]

From the results of Example 1, Example 2 and Example 3 in Table 1 above, the addition amounts of the Tg depressant and silica were within the range of the present invention, and the take-up speed was 3000 m / min or more and the above-mentioned. In the present invention in which the melt spinning is performed under the conditions represented by the relational expressions and, it is understood that the fiber strength is as large as 4.0 g / denier or more and the spinning state is good. From the results of Comparative Example 1, Comparative Example 2 and Comparative Example 3, when the aromatic polyester containing no Tg depressant and / or silica is used, the spinning pressure is the same even if other requirements are the same as the present invention. It can be seen that the spinning rate is increased and spinning is impossible, or that single yarn breakage occurs frequently and the spinning state is extremely poor. From the results of Comparative Example 4, Comparative Example 5 and Comparative Example 6, it is understood that when spinning is performed under the condition that the above relational expressions of and are not satisfied, the spinnability is extremely poor and winding is impossible.

[0063]

According to the present invention, a cationic dye-dyeable aromatic polyester having a specific proportion of a sulfonate group contains a specific amount of a Tg depressant and solid fine particles in an amount of 3000 m / min or more. Ultrafine fibers can be produced under the take-off speed and specific spinning temperature conditions. The spinning state of such fibers is good, and ultrafine fibers having a high strength of 3.5 g / denier or more can be obtained.

Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location D01F 6/92 Q7199-3B

Claims (3)

[Claims] 1. An aromatic polyester having a sulfonate group, which contains 1 to 5% by weight of a glass transition point depressant and 0.1 to 1.0% by weight of solid fine particles, and has a length of 3000 m.
Melt-spinning at a take-up speed of at least 1 / min to produce a fiber having an average fineness of 1 denier or less, the melt-spinning is performed under conditions satisfying the following formulas and: A method for producing a dyeable polyester ultrafine fiber. [Equation 1] T ↓ H −T ↓ N <20 [Equation 2] 250 ≦ T ↓ A <T ↓ H [where T ↓ H is the spinning temperature (° C) and T ↓ N is the spinning nozzle temperature (° C)] , T ↓ A is 30 cm from directly below the spinning nozzle
Ambient temperature within the range (℃)] 2. The aromatic polyester having a sulfonate group has a dicarboxylic acid component having a sulfonate group of 1.2 to all carboxylic acid components constituting the polyester.
The production method according to claim 1, wherein the polyester is copolymerized at a ratio of 2.0 mol%. 3. A dicarboxylic acid component having a sulfonate group is based on 5-sodium sulfoisophthalic acid, solid fine particles are silica having an average particle size of 15 to 70 mμ, and a glass transition point depressant is represented by the following general formula: (I): embedded image R ↓ 1 O—X—OR ↓ 2 (I) (In the formula, X is an aromatic group, R ↓ 1 and R ↓ 2 have 6 carbon atoms.
~ 18 alkyl groups or arylalkyl groups)
The method according to claim 1, which is at least one compound represented by