JPH05230713A - Spinning of readily dyeable polyester fiber - Google Patents

Abstract

PURPOSE:To produce the subject fiber with an excellent spinnability by spinning a copolyester containing a phosphonium sulfonate as a copolymer unit in a specified condition. CONSTITUTION:A phosphonium sulfonate (e.g. tetramethylphosphonium 3,5- dicarbomethoxybenzenesulfonate) of the formula (A is an aromatic group or an aliphatic group. X1 and X2 are independently an ester-forming functional group; n is a positive integer; R1 to R4 are independently H, an alkyl, an aryl or a hydroxyalkyl and the total molecular weight of R1 to R4 is >=60) is copolymerized into a polyester polymer chain. The resultant copolyester is subsequently subjected to melt spinning at 3500 to 8000m/min drawing rate and >=700/M [M is the ratio (mol%) of the copolymerized phosphonium sulfonate based on the whole acid components] draft ratio.

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 polyester fibers, and more particularly to a method for producing easily dyeable polyester fibers which can be dyed in a dark color in boiling water under normal pressure.

[0002]

2. Description of the Related Art Generally, polyester fibers, especially polyethylene terephthalate fibers, have many excellent properties such as strength and dimensional stability and are used for various purposes. On the other hand, polyethylene terephthalate fibers have poor dyeability and require special equipment for dyeing at high temperature and high pressure of around 130 ° C., and also with fibers such as wool and acrylic that cause deterioration in properties due to high pressure dyeing. It has drawbacks such as limited mixing.

Several attempts have been made to improve the dyeability of polyethylene terephthalate fiber and to make it dyeable under atmospheric pressure. For example, a method of using a carrier at the time of dyeing is known, but it requires a special carrier and dyeing. There are drawbacks such as difficulty in liquid post-treatment. Polyethylene terephthalate having improved dyeability is also known as a copolymer of a metal sulfonate group-containing compound and a polyether. These modified polyesters have improved dyeability, but are difficult to polymerize and spin. Alternatively, there are drawbacks such as deterioration of the original excellent properties of polyethylene terephthalate and deterioration of dyeing fastness.

As another method for improving the dyeability, attempts have been made without chemical modification, and for example, methods such as high-speed spinning, high-draft spinning, and highly irregular cross-section are known. However, although the approach using only these physical modifying means can obtain some easy dyeability, it is difficult to improve the dyeability to the level of atmospheric pressure dyeability.

Naturally, a combination of these modification methods, for example, high-speed spinning of chemically modified polyester has been proposed, but it is often unreasonable as a yarn-making technique, and production such as yarn breakage during spinning occurs. There was a problem in terms of performance.

[0006]

DISCLOSURE OF THE INVENTION The present inventors intend to obtain a polyester fiber which overcomes the drawbacks of the conventional method, has good dyeability, and can be dyed under atmospheric pressure and has a good condition in the spinning process. As a result of advancing research from the viewpoint of polymer modification and spinning process, the present invention was found to achieve the above object by combining specific chemical modification methods and spinning methods that were not known in the past. completed.

[0007]

[Means for Solving the Problems] That is, the present invention provides the following general formula:

[0008]

[Chemical 2]

[Wherein A is an aromatic group or an aliphatic group, X ₁
And X ₂ are the same or different ester-forming functional groups, n
Is a positive integer, R ₁ , R ₂ , R ₃ and R ₄ are hydrogen atoms,
The same or different groups selected from an alkyl group, an aryl group and a hydroxyalkyl group, wherein R ₁ , R ₂ and R
₃ indicates that the total molecular weight of R ₄ is 60 or more]
A method for producing easily dyeable polyester fibers is characterized in that a polyester copolymerized with a phosphonium salt of sulfonic acid is subjected to high-speed spinning under the conditions satisfying the following and at the same time. Take-up speed: 3500-8000 m / min Draft rate: 700 / M or more [where M represents the copolymerization amount (mol%) of the phosphonium sulfonate salt with respect to all acid components] The polyester in the present invention is terephthalic acid. The main object is a polyester having a main acid component of at least one glycol, preferably at least one alkylene glycol selected from ethylene glycol, trimethylene glycol and tetramethylene glycol.

Further, it may 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 a glycol other than the main component or another diol component. The polyester may be replaced with.

Examples of the bifunctional carboxylic acid other than terephthalic acid used here include isophthalic acid, naphthalene dicarboxylic acid, diphenyl dicarboxylic acid, diphenoxyethane dicarboxylic acid, β-hydroxyethoxybenzoic acid and p-oxybenzoic acid. , Adipic acid, sebacic acid,
Aromatic, aliphatic, and alicyclic difunctional carboxylic acids such as 1,4-cyclohexanedicarboxylic acid can be mentioned. Furthermore, within the range where the effect of the present invention is substantially exhibited,
Isophthalic acid having a metal sulfonate group such as sodium sulfoisophthalic acid may be used as a copolymerization component, but in this case, it is desirable to control the amount used to less than 1.0 mol% based on the terephthalic acid component. ..

Examples of the diol compound other than the above-mentioned glycol include aliphatic, alicyclic and aromatic diol compounds such as cyclohexane-1,4-dimethanol, neopentyl glycol, bisphenol A and bisphenol S, and polyoxyalkylene. Examples thereof include glycol.

In the present invention, the following general formula is included in the polymer chain of the polyester.

[0014]

[Chemical 3]

It is necessary that the phosphonium sulfonate represented by is copolymerized. In the above general formula, A is an aromatic group or an aliphatic group, preferably an aromatic group. X
₁ and X ₂ are ester-forming functional groups, examples of which include a carboxyl group, a chlorocarboxyl group, a hydroxyl group, and an acyloxy group.

[0016]

[Chemical 4]

(However, R is a lower alkyl group or a phenyl group, k is an integer of 1 or more, and m is an integer of 2 or more)
Etc. can be given. X ₁ and X ₂ may be the same or different. R ₁ , R ₂ , R ₃ and R
₄ is a hydrogen atom, an alkyl group, an aryl group or a hydroxyalkyl group, preferably an alkyl group, and particularly preferably a butyl group. The R ₁ , R ₂ , R ₃ and R ₄ may be the same or different. However, the sum of the molecular weights of R ₁ , R ₂ , R ₃ and R ₄ is 60 for the reason described below.
It is necessary to be above. In addition, n is a positive integer, usually 1 or 2.

Specific examples of such sulfonic acid phosphonium salt include 3,5-dicarbomethoxybenzenesulfonic acid tetramethylphosphonium salt, 3,5-dicarbomethoxybenzenesulfonic acid tetrabutylphosphonium salt,
Examples include 3,5-dicarbomethoxybenzenesulfonic acid tributylmethylphosphonium salt, 2,6-dicarbomethoxynaphthalene-4-sulfonic acid tetrabutylphosphonium salt, and 2,6-dicarbomethoxybenzenesulfonic acid tetramethylphosphonium salt. Be done.

In order to copolymerize the above-mentioned phosphonium sulfonate salt into the main chain of the polyester, it is preferable to carry out the above-mentioned polyester synthesis at any stage, preferably the first stage, before the completion of the polyester synthesis.
The compound may be added at any stage before the end of the stage reaction. At this time, if the amount used is too small, the dyeability will be insufficient, and the spinnability will be insufficient, especially at ultra-high speeds. On the contrary, if the amount is too large, the spinnability is deteriorated and the mechanical properties of the finally obtained polyester fiber are deteriorated. Therefore, the amount is 0.5 with respect to the difunctional carboxylic acid component constituting the polyester fiber. It is preferably used in the range of about 2.5 mol%.

In the present invention, the polyester specially designed as described above is 3500 m / min or more and 8000 m / min or more.
High-speed spinning is performed at a take-up speed of less than a minute. Here, when the take-up speed is less than 3500 m / min, the mechanical properties and shrinkage properties are generally insufficient for use as they are. Therefore, even if these low spinning speed take-up yarns are further drawn to improve their properties, it is impossible to obtain an easy dyeing level that can be said to be dyeable under normal pressure. On the other hand, if it exceeds 8000 m / min, the spinning condition will be deteriorated and the performance will be deteriorated. Further, it is more preferable to use the high-speed spun fiber collected at the above spinning speed as it is without stretching. However, depending on the purpose of use, it may be directly connected to the spinning or may be appropriately subjected to some stretching or heat treatment in a step different from the spinning. However, the higher the draw ratio, the lower the dyeability, so the draw ratio should be at most 1.5 times in order to maintain the level of dyeing under normal pressure.

[0021] Generally, high-speed spinning of chemically modified polyester remarkably deteriorates the tone of spinning. However, in the present invention, the high-speed spinnability of polyester is remarkably improved by copolymerizing a specific phosphonium sulfonate salt.

The reason for this is as follows. That is, if there is a nonuniform portion such as entanglement of molecular chains in the melt stream that is being spun at high speed, excessively strong stress concentrates at that portion. This becomes remarkable as the take-up speed of the spinning becomes higher,
It is a major cause of running filament cutting. In order to avoid this micro stress concentration, there are means such as increasing the spinning temperature and shortening the molecular chain length of polyester, but there are limitations to these means, and there are drawbacks such as deterioration of mechanical properties. Is attached.

On the other hand, in the polyester of the present invention,
A phosphonium base having a substantially bulky volume, P ⁺ R ₁ R ₂ R ₃ R _4, is sandwiched between molecular chains,
As a result, the distance between adjacent molecular chains can be increased. As a result, the probability of entanglement between molecular chains becomes extremely low, micro stress concentration is avoided, and spinnability is improved.

Therefore, the bulkiness of P ⁺ R ₁ R ₂ R ₃ R ₄ is important, and when the total molecular weight of R ₁ R ₂ R ₃ R ₄ does not reach 60, the effect of eliminating adjacent molecular chains is obtained. Becomes smaller and the spinnability is not improved.

Based on the same idea, when a side chain having the same bulkiness as P ⁺ R ₁ R ₂ R ₃ R ₄ of the polyester according to the present invention is given to the polyester (that is, a branched polyester), On the contrary, the high-speed spinnability is deteriorated. The reason for this is that the branch point itself becomes the stress concentration point, although the distance between adjacent molecular chains will be widened.
In the case of the polyester of the present invention, P ⁺ R ₁ R ₂ R ₃ R
_{Since 4} and the polyester body are moderately and lightly bound by an ionic bond, they can be easily dissociated when a strong external force is applied, and stress concentration can be avoided.

The polyester fiber of the present invention is 700
It is necessary to perform high-speed spinning at a high draft rate of / M or more. That is, the smaller the copolymerization rate, the higher the draft rate is required. Even if the draft rate does not reach 700 / M, a considerable dyeability is obtained, but it does not reach the level of atmospheric dyeability.

In the case of high draft spinning, it has been previously reported that the dyeing speed becomes faster, but even in the case of ordinary polyester, it is unavoidable that the process condition of spinning and the like deteriorates. Further, high draft spinning of polyester chemically modified for the purpose of improving dyeability was extremely difficult. However, in the case of the present invention, surprisingly, by copolymerizing the specific components, a high draft and a high spinning speed can be achieved, and the reason is as described above. The draft rate in the present invention indicates the take-up speed / discharge linear speed.

[0028]

The polyester fiber produced by the present invention has an amorphous part having extremely low orientation and cohesiveness.
Further, as mentioned above, the molecular chains are mutually spread by the bulky phosphonium base, so that the dye molecules can more easily diffuse inside the polyester during the dyeing process. As a result, remarkable dyeing becomes possible,
It is possible to dye a dark color even in boiling water under normal pressure.

[0029]

Example 1 100 parts of dimethyl terephthalate, 66 parts of ethylene glycol, tetrabutylphosphonium salt of 3,5-dicarboxybenzene sulfonic acid in an amount described in Tables 1 and 2 (0 to 2.5 with respect to dimethyl terephthalate). Mol%, and the total molecular weight of R ₁ R ₂ R ₃ R ₄ is 228.), acetic acid, manganese tetrahydrate 0.03 parts (0.024 mol% relative to dimethyl terephthalate) in a transesterification can. After the charging, the temperature was raised from 140 ° C. to 230 ° C. in a nitrogen gas atmosphere for 4 hours, and the produced methanol was distilled out of the system to cause an ester exchange reaction. Subsequently, a 56% aqueous solution of orthophosphoric acid, 0.03 part (0.033 mol% relative to dimethyl terephthalate) and 0.04 part antimony trioxide (0.027 mol%) were added to the obtained product. Then, it was transferred to a polymerization can. Then 1 hour from 760mmHg to 1mm
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 a 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 polymer obtained was dried by a conventional method (1
(60 ° C, 4 hours), using a spinneret with 36 circular discharge holes of various diameters, discharge it in a molten state at a maximum temperature of 310 ° C, and after cooling and solidifying according to the usual method, rotate at various speeds. It was wound on a winder through a pair of godet rollers to obtain a multifilament of 75 de / 36 fil.

The polyester fiber obtained as described above is knitted, then scoured for 20 minutes at 60 ° C. using 2 g / liter of score roll, dried and conditioned (20 ° C. × 65%).
RH), then disperse dye Sumikaron Navy Blue S-2G
L, 3% owf, liquor ratio 1: 100 and dyed at 100 ° C.

On the other hand, for comparison, no copolymerization is carried out (M =
0) A normal polyester is collected at a speed of 1500 according to a conventional method.
75 de / 3 obtained by winding the fiber at m / min, stretching it 3.3 times, and heat-treating it at a slit heater of 180 ° C.
The same dyeing test was carried out at 6O <0> C for 6fil multifilament as well as at 130 <0> C with a high-pressure dyeing machine.

Tables 1 and 2 show the process conditions of the above-mentioned yarn making process, the mechanical properties of the obtained polyester filament, and the dyeability.

However, in the table, M represents the copolymerization ratio (mol%) of tetrabutylphosphonium 3,5-dicarboxybenzenesulfonate. In addition, the spinning condition ◯ is good, Δ is occasionally single yarn breakage, and × is not spinning.

Regarding dyeability, the above-mentioned root spinning
The dyeing level when the drawn yarn is dyed under high pressure at 130 ° C is ○,
The dyeing level when dyed at 100 ° C is x, the intermediate level is Δ, and the one dyed deeper than 130 ° C high pressure dyeing is ◎.
Expressed as

[0036]

[Table 1]

[0037]

[Table 2]

In the above table, No. No. 1 is a normal polyester spun at a high speed and gives a deeper dye than a normal drawn yarn, but does not reach the same level of dyeability as when dyed at 130 ° C. In addition, No. 2 is an example of increasing the spinning draft rate,
No. No. 3 is an example in which the spinning speed was increased, and although the dyeability is improved in all cases, it is still insufficient as compared with 130 ° C. dyeing.

On the other hand, No. 4 to No. No. 30 is an example using a polyester in which a phosphonium sulfonate salt is copolymerized, and among these, the spinning take-up speed is 3500 m /
If the minutes are not reached (No. 4, 5, 11, 12),
In addition to high elongation, there are problems such as high shrinkage and insufficient dyeability, and when it exceeds 8000 m / min (N
o. 23, 24, 30), although the dyeability is good, the process condition of yarn production is lowered and stable production cannot be achieved. When the draft rate does not meet the requirements of the present invention (No. 9, 13, 16, 20), the dyeability is improved, but the level is not so high that it is dyeable under normal pressure. Absent.

On the other hand, when the requirements of the present invention are satisfied, the thread-forming tone and the mechanical properties of the obtained fiber are at a good level, and the dyeability is 1
It is at a level equivalent to or higher than that of high-pressure dyeing at 30 ° C.

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, n is a positive integer,
R ₁ , R ₂ , R ₃ and R ₄ are a hydrogen atom, an alkyl group,
The same or different groups selected from an aryl group and a hydroxyalkyl group, wherein the total molecular weight of R ₁ , R ₂ , R ₃ and R ₄ is 60 or more]. A method for producing easily dyeable polyester fibers, which comprises subjecting a copolymerized polyester to high-speed spinning under the conditions which simultaneously satisfy the following conditions. Take-up speed: 3500-8000 m / min Draft rate: 700 / M or more [where M represents the copolymerization amount (mol%) of the phosphonium sulfonate salt with respect to all acid components]