JPH0361767B2 - - Google Patents

Description

[Detailed description of the invention]

<Field of Application> The present invention relates to a method for producing ultrafine polyester yarn, and more particularly to a method for producing ultrafine polyester yarn that can be stained with basic dyes and has excellent mechanical properties and spinning properties. <Prior Art> Polyester has many excellent properties and is therefore widely used as a fiber, but its dyeability is low, and in particular cannot be dyed with basic dyes. In order to improve this dyeability, a method is known in which a sodium sulfoisophthalic acid component is copolymerized into the polyester main chain. On the other hand, it is also known that in order to give a uniquely soft and good texture to woven or knitted fabrics made of polyester fibers, the single yarn fineness can be reduced, and in this case, 2000
Ultrafine yarn with a single fiber fineness of 1.0 to 0.1 de is used, which is produced using high speed spinning of ~4000 m/min. However, by high-speed spinning using a modified polyester that contains the metal sulfonate groups mentioned above and can be dyed with basic dyes, the fineness of the single yarn can be improved.
Even if an attempt is made to produce ultrafine yarn of 1.0 de or less, the above-mentioned modified polyester has extremely poor spinnability, and single filament breakage occurs frequently during spinning, making it impossible to spin, or even if spinning is possible, the resulting yarn is It is not actually used because its mechanical properties are extremely low and it cannot withstand use. In order to solve this problem, attempts were made to improve high-speed spinning conditions, such as the shape of the spinneret discharge hole, spinning temperature, cooling conditions, filament focusing, shortening the running length between the spinneret and the winder, and providing focusing using an interlace nozzle. However, these measures had limitations and no significant improvement could be expected. <Objective of the Invention> The object of the present invention is to solve the above-mentioned problems in ultrafine polyester yarn dyeable with basic dyes, and to improve mechanical properties and
To provide a method for producing ultrafine polyester yarn having excellent spinning properties, dyeability, and color fastness. <Structure of the Invention> As a result of intensive research aimed at achieving the above object, the present inventors have found that the desired effect can be achieved when a modified polyester copolymerized with a sulfonic acid phosphonium salt is used in place of the conventional sodium sulfoisophthalate. The present invention was achieved by investigating the following. That is, the present invention is based on the following general formula [Wherein A is an aromatic group or an aliphatic group, X ₁ and X ₂
are the same or different ester-forming functional groups, R ₁ ,
R ₂ , R ₃ and R ₄ are the same or different groups selected from a hydrogen atom, an alkyl group, an aryl group and a hydroxyalkyl group, n is a positive integer] 3000 polyester with a viscosity of 0.5 or more
This is a method for producing ultrafine polyester yarn, which is characterized in that it is melt-spun at a take-up speed of m/min or higher to produce a multi-fiber yarn with an average fineness of single yarns of 1.0 de or less. The polyester in the present invention is a polyester having terephthalic acid as the main acid component and at least one type of glycol, preferably at least one alkylene glycol selected from ethylene glycol, trimethylene glycol, and tetramethylene glycol as the main glycol component. The main target is It may also be a polyester in which a part of the terephthalic acid component is replaced with another difunctional carboxylic acid component, and/or a part of the glycol component is replaced with the above-mentioned glycol or other diol component other than the main component. It may also be polyester. Examples of difunctional carboxylic acids other than terephthalic acid used here include isophthalic acid, naphthalene dicarboxylic acid, diphenyl dicarboxylic acid,
Aromatic, aliphatic, and alicyclic difunctional carboxylic acids such as diphenoxyethanedicarboxylic acid, β-hydroxyethoxybenzoic acid, p-oxybenzoic acid, adipic acid, sebacic acid, and 1,4-cyclohexanedicarboxylic acid. can be given. Furthermore, isophthalic acid having a metal sulfonate group such as 5-sodium sulfoisophthalic acid may be used as a copolymerization component within the range where the effects of the present invention can be substantially achieved. It is desirable to suppress the amount to less than 1.8 mol%. Examples of diol compounds other than the above-mentioned glycols include aliphatic, alicyclic, and aromatic diol compounds such as cyclohexane-1,4-dimethanol, neopentyl glycol, bisphenol A, and bisphenol S, and polyoxyalkylene glycols. etc. can be given. Furthermore, polycarboxylic acids such as trimellitic acid and pyromellitic acid, polyols such as glycerin, trimethylolpropane, and pentaerythritol can be used as long as the polyester is substantially linear. Such polyesters may be synthesized by any method. For example, in the case of polyethylene terephthalate, usually terephthalic acid and ethylene glycol are directly esterified, a lower alkyl ester of terephthalic acid such as dimethyl terephthalate is transesterified with ethylene glycol, or terephthalic acid and ethylene glycol are transesterified. The first stage reaction is to react with terephthalic acid to produce a glycol ester and/or its low polymer, and the first stage reaction product is heated under reduced pressure until the desired degree of polymerization is achieved. It is produced by a second stage reaction of polycondensation. In the present invention, the following general formula is present in the polymer chain of the polyester. It is necessary that the sulfonic acid phosphonium salt represented by is copolymerized. In the above general formula, A is an aromatic group or an aliphatic group, and an aromatic group is preferable. X ₁ and X ₂ are ester-forming functional groups, and examples thereof include carboxyl group, chlorocarboxyl group, hydroxyl group, acyloxy group, etc. Preferred specific examples include

【formula】 【formula】

[Formula] (-CH ₂ ) _l OH, -O(CH ₂ )- _n [-O(CH ₂ )- _n ]- _l O
H,

[Formula] (However, R is a lower alkyl group or a phenyl group,
l represents an integer of 1 or more, m represents an integer of 2 or more)
etc. can be given. X ₁ and X ₂ may be the same or different. _R1 , _R2 , _R3
and R ₄ is a hydrogen atom, an alkyl group, an aryl group,
It is a hydroxyalkyl group, preferably an alkyl group, and particularly preferably a butyl group. this
R ₁ , R ₂ , R ₃ and R ₄ may be the same or different. Further, n is a positive integer, usually 1 or 2. Such sulfonic acid phosphonium salts can generally be easily synthesized by reacting the corresponding sulfonic acid with phosphines or by reacting the corresponding sulfonic acid metal salt with phosphonium halides. When synthesizing from sulfonic acid and phosphine, it is not necessarily necessary to isolate the salt, and the corresponding sulfonic acid and phosphine may be added to the polyester to be modified to generate a salt within the polyester reaction system. However, when synthesizing from a sulfonic acid metal salt and a phosphonium halide, the inorganic salts produced have negative effects, such as lowering the softening point due to excessive side reactions and making it impossible to increase the degree of polymerization. It must be added to the polyester after sufficient salt removal. Specific examples of the sulfonic acid phosphonium salts include 3,5-dicarbomethoxybenzenesulfonic acid tetramethylphosphonium salt, 3,5-dicarbomethoxybenzenesulfonic acid tetrabutylphosphonium salt, and 3,5-dicarbomethoxybenzenesulfonic acid. Tributylmethylphosphonium salt, 2,
Examples include 6-dicarbomethoxynaphthalene-4-sulfonic acid tetrabutylphosphonium salt, 2,6-dicarbomethoxybenzenesulfonic acid tetramethylphosphonium salt, and the like. In order to copolymerize the sulfonic acid phosphonium salt into the main chain of the polyester, the above-mentioned phosphonium salt can be copolymerized at any stage before the synthesis of the polyester described above is completed, preferably at any stage before the first stage reaction is completed. Just add the compound. In this case, if the amount used is too small, there will be insufficient dyeing seats in the final polyester fiber, resulting in insufficient dyeability with basic dyes, and conversely, if it is too large, the softening point of the resulting polymer will be As a result, the mechanical properties and other yarn properties of the final polyester fibers will deteriorate.
It is used in a range of 0.5 to 3.5 mol%, preferably 0.7 to 2.0 mol%. The modified polyester obtained in this way is
It is necessary that the intrinsic viscosity [η] is 0.5 or more, preferably 0.6 or more. If it is less than 0.5, the mechanical properties, especially the strength, of the obtained ultrafine polyester yarn will be insufficient, and the object of the present invention will not be achieved.
Note that the intrinsic viscosity [η] is given by lim c→o{ln(ηrel)}/c. Here, ηrel is the ratio of the viscosity of a dilute polyester solution using orthochlorophenol as a solvent to the viscosity of the solvent measured at the same temperature and in the same units, and c is
100c.c. is the number of grams of polyester in the mixture. In the present invention, the above modified polyester is
The fibers are melt-spun at a take-up speed of 3000 m/min or more to produce a multi-filament yarn having an average fineness of 1.0 de or less, preferably 0.8 de or less, more preferably 0.6 de or less. With the conventional basic dye-dyable polyester copolymerized with sodium sulfoisophthalic acid, it has been impossible to produce such ultrafine yarns because of extremely poor spinning characteristics. In addition, the strength of the obtained ultra-fine thread is 3.5 g/de or more,
Furthermore, it is desirable to set it to 4.0 g/de or more. With conventional basic dye dyeable polyester, fibers with such strength cannot be obtained, and the strength is at most 2.5 to 3.0 g/
However, its use was extremely limited. When melt-spinning the above-mentioned modified polyester at a take-up speed of 3000 m/min or more, it is effective to appropriately employ one or more of the following means (a) and (e). (b) The distance from the spinneret to the first take-up roller is 4
m or less to reduce air resistance on the running yarn. (b) Within a range of 0.3 to 2 m downstream of the spinneret, it is focused and cooled using an oil supply guide or the like. (c) A non-contact heating area with an ambient temperature of 150° C. or higher is provided within a range of 1 to 4 m downstream of the spinneret. (d) In the process up to winding the discharged yarn, heat treatment is performed using one or more hot rollers or the like. (E) During the spinning process, air resistance is reduced by converging with an air nozzle and/or guide as necessary. The yarn thus obtained can be subjected to stretching, heat treatment, crimping, etc., as necessary. <Actions and Effects of the Invention> According to the present invention, it is possible to produce ultrafine yarn with high productivity, which could never be produced with conventional basic dye-dyeable polyesters, such as modified polyesters copolymerized with sodium sulfoisophthalic acid components. made possible. The reason for this is thought to be due to the following mechanism. That is, in a conventional modified polyester copolymerized with a sodium sulfoisophthalic acid component as a modifier, ionic bonds are generated between the modifiers via metal ions, and the molecular chains take on a light crosslinked structure.
When such a polymer is melt-spun at high speed, strong elongation stress is concentrated at the crosslinking points, which significantly deteriorates the spinnability at high speed. In particular, in the case of ultra-fine yarns with small single filament fineness, the tension due to air drag increases significantly, so the deterioration in spinnability at high speeds becomes fatal. In contrast, in the present invention, since the ionic component of the modifier used is covered with bulky substituents R ₁ , R ₂ , R ₃ , and R ₄ , ionic crosslinking between molecular chains is considerably suppressed due to the steric hindrance. be done. Therefore, concentration of tensile stress during spinning becomes difficult to occur, and high-speed spinnability of the ultrafine yarn is improved. This effect becomes even greater when combined with other techniques described in this specification, such as reducing air resistance by converging discharged multi-yarns, shortening running length, etc. Therefore, according to the present invention, it is possible to easily produce polyester ultrafine yarn that is dyeable with a basic dye and has good mechanical properties, particularly high strength and tear strength. The obtained ultrafine yarn is a fiber most suitable for use in the field of high-density woven and knitted fabrics, particularly in the field of sports clothing, which has waterproof and moisture-permeable properties. Conventionally, using ultrafine polyester yarns that can only be dyed with disperse dyes in this field has resulted in insufficient dyeing fastness and problems with color migration. Not only is there a limit to the fine denier due to the lack of high-speed spinnability, but the yarn strength is low, which causes problems such as a weakening of the tear strength of the fabric, and it cannot be used in practice. The present invention made it possible for the first time to use polyester yarn in this field. <Examples> The present invention will be specifically described below with reference to Examples, but the present invention is not limited to these Examples. Examples 1 to 5 and Comparative Examples 1 to 5 100 parts of dimethyl terephthalate, 66 parts of ethylene glycol, 3,5-dicarboxybenzenesulfonic acid tetrabutylphosphonium salt in the amounts listed in Table 1 (range 0 to 4.3 parts) ), 0.03 part of manganese acetate tetrahydrate (0.024 mol% relative to dimethyl terephthalate) was charged into a transesterification reactor, and the temperature was raised from 140°C to 230°C over 4 hours under a nitrogen gas atmosphere to carry out a transesterification reaction while distilling the generated methanol out of the system. Subsequently, 0.03 part of a 56% aqueous solution of orthophosphoric acid (0.033 mol% relative to dimethyl terephthalate) and 0.04 part of antimony trioxide (0.027 mol%) were added to the obtained product, and the mixture was transferred to a polymerization vessel. Then 1mm from 760mmHg over 1 hour
The pressure was reduced to Hg, and at the same time the temperature was raised from 230°C to 280°C over 1 hour and 30 minutes. Polymerization was carried out under reduced pressure of 1 mmHg or less at a polymerization temperature of 280° C. until the intrinsic viscosity shown in Table 1 was reached. The obtained polyester was vacuum dried at 120℃ for 6 hours, melted at a maximum of 310℃ using a spinneret with 72 circular discharge holes with a hole diameter of 0.15mm, and spun at a high speed of 4300m/min. An ultrafine yarn of 36 denier/72 filaments (single yarn 0.5 denier) was obtained. Incidentally, the yarn running distance from the spinneret to the first take-up roller (godet roller) was 3 m. The spinning condition at this time. Table 1 shows the physical properties of the obtained ultrafine thread. On the other hand, for comparison, modified polyesters copolymerized with a sodium sulfoisophthalic acid component were used in Comparative Examples -4 and -5, and the results were also shown in Table 1 by spinning in the same manner as above.

[Table] Comparative Example 1 has good spinning condition and mechanical properties, but cannot be dyed with basic dyes. In Comparative Example 2, the amount of the agent added was too large, 4 mol %, so that the spinning condition deteriorated considerably and the strength of the resulting polyester yarn decreased. Comparative Example 3 has a low intrinsic viscosity and a good spinning condition, but the strength still remains at a low level. Comparative example-4 and 5
is an example in which sodium dimethyl sulfoisophthalate, which has been conventionally used as a cationic dye agent, is copolymerized, and the spinning condition is extremely poor. On the other hand, Examples 1 to 5 are based on the present invention, and both the spinning condition and the strength of the obtained ultrafine yarns are sufficiently good.

Claims (1)

[Claims] 1. The following general formula [Wherein A is an aromatic group or an aliphatic group, X ₁ and X ₂
are the same or different ester-forming functional groups, R ₁ ,
R ₂ , R ₃ and R ₄ are the same or different groups selected from a hydrogen atom, an alkyl group, an aryl group and a hydroxyalkyl group, n is a positive integer] 3000 polyester with a viscosity of 0.5 or more
1. A method for producing ultrafine polyester yarn, which comprises melt spinning at a take-up speed of m/min or more to produce a multi-fiber yarn with an average fineness of single yarn of 1.0 de or less. 2. Claim 1, wherein the copolymerized amount of the sulfonic acid phosphonium salt is 0.5 to 3.5 mol% based on the bifunctional carboxylic acid component constituting the polyester.
A method for producing ultrafine polyester yarn as described in Section 1. 3 In the general formula representing a sulfonic acid phosnium salt,
The method for producing ultrafine polyester thread according to claim 1 or 2, wherein R ₁ , R ₂ , R ₃ and R ₄ are butyl groups. 4. The method for producing ultrafine polyester yarn according to any one of claims 1 to 3, wherein the polyester is a polyester whose main constituent unit is ethylene terephthalate. 5. The method for producing ultrafine polyester yarn according to any one of claims 1 to 4, wherein the ultrafine polyester yarn has a strength of 3.5 g/de or more. 6 The average fineness of a single yarn of polyester ultrafine yarn is
The method for producing ultrafine polyester yarn according to any one of claims 1 to 5, wherein the polyester ultrafine yarn has a thickness of 0.6 de or less.