CN114573800A

CN114573800A - Cationic dyeable polyester composition, preparation method and application thereof

Info

Publication number: CN114573800A
Application number: CN202011297142.0A
Authority: CN
Inventors: 祁华; 胡永佳; 望月克彦
Original assignee: Toray Fibers and Textiles Research Laboratories China Co Ltd
Current assignee: Toray Fibers and Textiles Research Laboratories China Co Ltd
Priority date: 2020-11-18
Filing date: 2020-11-18
Publication date: 2022-06-03

Abstract

The application discloses a cationic dyeable polyester composition and a preparation method thereof. The cationic dyeable polyester composition mainly comprises an aromatic dicarboxylic acid structural unit and an aliphatic diol structural unit, wherein the cationic dyeable polyester composition comprises a compound shown in the formula 1 (A)

Description

Cationic dyeable polyester composition, preparation method and application thereof

Technical Field

The invention relates to a cationic dyeable polyester composition, in particular to a polyester composition containing a blocked sulfonate group at the tail end and an aliphatic dicarboxylic acid structural unit.

Background

Polyester resins are widely used in industrial fields such as clothing, industrial fibers, magnetic tapes, surface coating films, and tire meridian and mesh lines because of their excellent mechanical and chemical properties.

When used as a clothing fiber, in order to improve the dyeability of polyester, a copolymer modified cationic dyeable polyester is obtained by using an isophthalic acid component containing a sulfonate group, such as isophthalic acid-5-sodium sulfonate, as a comonomer. However, the sulfonate group is easy to physically crosslink in the polyester, so that the melt viscosity of the polyester is obviously increased under the condition of low Inherent Viscosity (IV), and the strength of the finally obtained yarn is low; meanwhile, the strength retention rate before and after yarn dyeing is poor, so that the application of the yarn in some fields with high strength requirements is limited.

Japanese patent laid-open No. 5-25708 discloses a modified polyester fiber, which is modified by using a component with blocked cation at the tail end, polyether and diol, the cation group in the obtained modified polyester is mainly connected at the tail end of a molecular chain, no physical crosslinking group is arranged in the middle of the molecular chain, the viscosity of the polyester is greatly reduced, the strength of the obtained cation polyester fiber is greatly improved compared with the prior polyester modified by the isophthalic acid component of sulfonate groups, and the spinning performance is not problematic. However, the cationic group is mainly connected to the molecular weight end, which affects the dyeing property of the modified polyester, and the addition of the end blocking cationic component generally causes poor polyester reactivity, and the obtained polyester has the problems of low molecular weight and low strength.

Disclosure of Invention

The invention aims to provide a cationic dyeable polyester composition which is easy to dye, hydrolysis-resistant and high in strength and a preparation method thereof.

The technical solution of the invention is as follows:

the cationic dyeable polyester composition mainly comprises an aromatic dicarboxylic acid structural unit and an aliphatic diol structural unit. The polyester composition contains a sulfonate group shown in a formula 1, and the content of the group shown in the formula 1 accounts for 1000-5000 ppm, preferably 1000-3500 ppm of the total amount of the polyester composition in terms of sulfur element; the polyester composition contains aliphatic dicarboxylic acid structural units;

in the formula 1, the compound is shown in the specification,

in the formula 1, Y is alkyl, phenyl or alkylbenzene with 2-20 carbon atoms, and Z is Li ion, Na ion or K ion.

The number of carbon atoms of the aliphatic dicarboxylic acid is preferably 4 to 10, and the amount of the aliphatic dicarboxylic acid or an esterified derivative thereof added is preferably 0.1 to 10.0wt% of the total amount of the polyester composition.

The molar ratio of the alkali metal element to the sulfur element in the polyester composition is preferably greater than 1.00.

The polyester composition has a hydrolysis resistance index delta COOH of less than 80eq/t after being treated for 4 hours under saturated water vapor with the temperature of 155 ℃ and the humidity of 100 percent.

The invention also discloses a preparation method of the cationic dyeable polyester composition, which comprises the steps of firstly carrying out esterification or ester exchange reaction on aromatic dicarboxylic acid or esterified derivatives thereof and aliphatic diol to obtain oligomers, then carrying out polymerization reaction on the oligomers, and finally carrying out solid-phase polymerization to obtain the polyester composition. Adding a sulfonate compound shown as a formula 2 and aliphatic dicarboxylic acid or an esterified derivative thereof at any stage before the polymerization reaction is finished, wherein the adding amount of the sulfonate compound shown as the formula 2 is 1000-5000 ppm, preferably 1000-3500 ppm calculated by sulfur element relative to the total amount of the polyester composition,

in the formula (2), the first and second groups,

in the formula 2, Y is alkyl, phenyl or alkylbenzene with 2-20 carbon atoms, and Z is Li ion, Na ion or K ion.

The number of carbons in the aliphatic dicarboxylic acid is preferably 4 to 10, and the amount of the aliphatic dicarboxylic acid added is preferably 0.1 to 10.0wt% based on the total amount of the polyester composition.

The alkali metal compound is added at an arbitrary stage before the completion of the polymerization reaction, and the amount of the alkali metal compound added is preferably 1000ppm or less based on the total amount of the polyester composition.

The sulfonate compound is preferably added 20 to 60min after the start of polymerization.

The reaction temperature of the solid-phase polymerization is preferably 200 to 240 ℃, the reaction pressure is preferably below 1000Pa, and the reaction time is preferably below 100 hours.

The alkali metal compound is preferably one or more of sodium acetate, lithium acetate and potassium acetate.

The polyester composition disclosed by the invention is easy to dye, good in hydrolysis resistance, low in content of by-products diethylene glycol and terminal carboxyl, and good in strength retention rate before and after dyeing, and can be applied to fibers.

Detailed Description

In the prior art, cationic dyeability is generally imparted to polyesters by copolymerizing in the polyester a cationic dyeable ingredient containing a sulfonate group, such as isophthalic acid-5-sulfonate or the like. However, since sulfonate groups are distributed in the middle of the molecular weight of the polyester, physical crosslinking of sulfonate groups in the polyester is likely to occur, resulting in an increase in the viscosity of the polyester and a decrease in the strength of the polyester. At the same time, the hydrolysis resistance of the polyester is also deteriorated.

The terminal blocked cation component is added into the polyester, the cation group in the modified polyester is mainly connected with the terminal of a molecular chain, and no physical crosslinking group with interaction exists in the middle of the molecular chain, so that the melt viscosity of the polyester can be improved. However, the cationic group is mainly connected to the molecular weight end, which affects the dyeing property of the modified polyester, and the addition of the end blocking cationic component generally causes poor polyester reactivity, and the obtained polyester has the problems of low molecular weight and low strength. By modifying polyester with aliphatic dicarboxylic acid and derivatives thereof, the dyeing property of polyester can be improved, and the molecular weight of modified polyester can be increased, so that the strength of polyester fiber is increased, and the strength retention rate of the polyester fiber before and after dyeing is improved.

The cationic dyeable ingredient used in the invention is a sulfonate compound shown as a formula 2,

in the formula (2), the first and second groups,

The sulfonate compound shown as the formula 2 only contains one hydroxyl reaction group, the sulfonate compound is mainly connected to the tail end of a molecular chain in the polyester, and no physical crosslinking group is interacted between the molecular chains, so that the obtained polyester has high molecular weight and high strength.

Specific examples thereof include sodium 2-carboxylbenzenesulfonate, potassium 2-carboxylbenzenesulfonate, sodium 3-carboxylbenzenesulfonate, lithium 3-carboxylbenzenesulfonate, sodium 4-carboxylbenzenesulfonate, methyl 2-sulfonate, methyl 3-sulfonate, methyl 4-sulfonate, ethyl 2-sulfonate, ethylene glycol 2-sulfonate, ethyl 3-sulfonate, ethylene glycol 4-sulfonate, and ethylene glycol 3-sulfonate, among which sodium 3-carboxylbenzenesulfonate is preferable.

The polyester composition added with the cationic dyeable component of the sulfonate compound shown as the formula 2 contains a sulfonate group shown as the formula 1,

in the formula 1, the compound is shown in the specification,

The content of the sulfonate group shown in the formula 1 in the polyester composition accounts for 1000-5000 ppm of the total amount of the polyester composition in terms of sulfur element. When the content of the sulfonate group shown in the formula 1 in the polyester composition is lower than 1000ppm, the obtained product is difficult to achieve satisfactory color concentration in the subsequent dyeing process; when the content of the sulfonate group represented by the formula 1 in the polyester composition is more than 5000ppm, the growth of the polyester molecular chain is suppressed, and the polymerization is terminated without reaching the target viscosity, so that a polyester composition having good physical properties cannot be obtained. In view of both dyeing properties and physical properties of the polyester composition, the content of the sulfonate group represented by the formula 1 is preferably 1000 to 3500ppm in terms of sulfur in the polyester composition.

In order to improve the dyeing property and the strength of the polyester composition, the polyester composition contains an aliphatic dicarboxylic acid structural unit, wherein the aliphatic dicarboxylic acid structural unit can be a straight-chain aliphatic dicarboxylic acid structural unit or a branched-chain aliphatic dicarboxylic acid structural unit, the number of carbon atoms of the aliphatic dicarboxylic acid structural unit is preferably 4-10, the aliphatic dicarboxylic acid structural unit can be specifically a succinic acid structural unit, an adipic acid structural unit, an azelaic acid structural unit, a sebacic acid structural unit, a 2, 2-dimethyl adipic acid structural unit and the like, and the succinic acid structural unit and the sebacic acid structural unit are preferably selected.

The content of the aliphatic dicarboxylic acid structural unit is preferably 0.1 to 10.0wt% relative to the total amount of the polyester composition. When the content of the aliphatic dicarboxylic acid structural unit is too low, the function of improving the dyeing property and the strength of the polyester composition is not achieved; when the content of the aliphatic dicarboxylic acid structural unit is too high, the polyester composition has poor heat resistance, and thermal decomposition is easily generated in subsequent processing, which affects the quality of the polyester composition product. The aliphatic dicarboxylic acid structural unit more preferably accounts for 0.5-8.0 wt% of the polyester composition.

The molar ratio of the alkali metal element to the sulfur element in the polyester composition of the invention is greater than 1.00. The alkali metal element includes an alkali metal element in a sulfonate group shown in formula 1 and an alkali metal element in an alkali metal compound other than sulfonate.

The polyester composition of the present invention has a terminal carboxyl group COOH of 40 eq/ton or less, and preferably has a hydrolysis resistance index [ Delta ] COOH of 80 eq/ton or less after treatment for 4 hours with saturated water vapor at 155 ℃ and 100% humidity.

The invention also discloses a preparation method of the cationic dyeable polyester composition, which comprises the steps of firstly carrying out esterification or ester exchange reaction on aromatic dicarboxylic acid or esterified derivatives thereof and aliphatic diol to obtain an oligomer, then carrying out polymerization reaction on the oligomer, and finally carrying out solid-phase polymerization to obtain the polyester composition.

Adding a sulfonate compound shown as a formula 2 at any stage before the polymerization reaction is finished,

in the formula (2), the first and second groups,

in the formula 2, Y is alkyl, phenyl or alkylbenzene with 2-20 carbon atoms, and Z is Li ion, Na ion or K ion. Specific examples thereof include sodium 2-carboxylbenzenesulfonate, potassium 2-carboxylbenzenesulfonate, sodium 3-carboxylbenzenesulfonate, lithium 3-carboxylbenzenesulfonate, sodium 4-carboxylbenzenesulfonate, methyl 2-sulfonate, methyl 3-sulfonate, methyl 4-sulfonate, ethyl 2-sulfonate, ethylene glycol 2-sulfonate, ethyl 3-sulfonate, ethylene glycol 4-sulfonate, and ethylene glycol 3-sulfonate, among which sodium 3-carboxylbenzenesulfonate is preferable.

The addition amount of the sulfonate compound shown as the formula 2 is 1000-5000 ppm relative to the total amount of the polyester composition in terms of sulfur element. When the addition amount of the sulfonate compound shown as the formula 2 is less than 1000ppm, the obtained product is difficult to achieve satisfactory color concentration in the subsequent dyeing process; when the amount of the sulfonate compound represented by the formula 2 is more than 5000ppm, the increase of the molecular chain of the polyester is suppressed, and the head beating phenomenon of polymerization is caused, and a polyester composition having good physical properties cannot be obtained. In view of both dyeability and physical properties of the polyester composition, the amount of the sulfonate compound represented by the formula 2 is preferably 1000 to 3500ppm in terms of sulfur in the polyester composition.

The sulfonate compound shown in the formula 2 can be added in any stage of esterification reaction, ester exchange reaction and polymerization reaction. When the polyester is added in the stage of esterification or transesterification, there is a risk that the polyester molecular chain segment is prematurely terminated and the polyester composition having a normal molecular weight range cannot be obtained, and the polyester composition contains a little more by-products than the conventional polyester and is also slightly inferior in dyeing stability and strength retention before and after dyeing. In order to obtain a polyester composition with high molecular weight and avoid the increase of byproducts in the polyester composition, the adding time of the sulfonate compound shown in the formula 2 is preferably in a polymerization reaction stage, enough time is left for the increase of the polyester molecular chain, and more preferably, the sulfonate compound is added 20min to 60min after the polymerization starts.

The sulfonate compound shown as the formula 2 is a powdery substance, so that when the sulfonate compound is added, the sulfonate compound shown as the formula 2 is dissolved in aliphatic diol to prepare aliphatic diol solution according to the conventional method in the field, and then the aliphatic diol solution is added. Specifically, according to the mass 1: 0.5-1: 10.0, and dissolving at 70-198 ℃ to form a uniform solution. The weight ratio of the sulfonate shown in the formula 2 to the aliphatic diol is preferably 1: 1.0-1: 2.0, and the optimal dissolving temperature is 80-130 ℃. The aliphatic diol solution can be prepared by the above-mentioned method, but is not limited thereto.

In addition, in order to improve the dyeing performance and strength of the polyester composition, the aliphatic dicarboxylic acid or its esterified derivative is added at any stage before the polymerization reaction is finished. The aliphatic dicarboxylic acid or the esterified derivative thereof can increase the flexible chain of the polyester composition, improve the mobility of the polyester composition, enable dye molecules to easily enter the polyester, and improve the dyeing property of the polyester composition. Meanwhile, the aliphatic dicarboxylic acid or the esterified derivative thereof can promote the polymerization reactivity of the polyester composition, improve the molecular weight of the polyester composition, facilitate the yarn alignment in the spinning engineering, improve the strength of the yarn, and improve the strength retention rate of the yarn before and after dyeing.

The aliphatic dicarboxylic acid or an esterified derivative thereof in the present invention refers to an aliphatic dicarboxylic acid or an esterified derivative of the aliphatic dicarboxylic acid. The number of carbon atoms of the aliphatic dicarboxylic acid is preferably 4 to 10, the number of carbon atoms of the esterified derivative of the aliphatic dicarboxylic acid is not particularly limited, and the number of carbon atoms of the esterified derivative may be more than 10, and any esterified derivative may be used as long as the esterified derivative is formed on the basis of the aliphatic dicarboxylic acid having 4 to 10 carbon atoms. For example, when the aliphatic dicarboxylic acid is sebacic acid, its esterified derivative may be dimethyl sebacate or diethyl sebacate.

The aliphatic dicarboxylic acid or an esterified derivative thereof may be a straight-chain aliphatic group or a branched-chain aliphatic group.

Specific examples thereof include succinic acid, adipic acid, azelaic acid, sebacic acid, 2-dimethyladipic acid, etc., and among them, succinic acid and sebacic acid structural units are preferable.

The amount of the aliphatic dicarboxylic acid or an esterified derivative thereof added is preferably 0.1 to 10.0wt% based on the total amount of the polyester composition. When the addition amount of the aliphatic dicarboxylic acid or the esterified derivative thereof is too low, the polyester composition does not have the effect of improving the dyeing performance and dyeing effect; when the amount of the aliphatic dicarboxylic acid or an esterified derivative thereof added is too high, the polyester composition has poor heat resistance and is likely to undergo thermal decomposition during subsequent processing, which affects the quality of the polyester composition product. The amount of the aliphatic dicarboxylic acid or an esterified derivative thereof to be added is more preferably 0.5 to 8.0wt% based on the polyester composition.

In addition, although the addition of the sulfonate compound as shown in formula 2 can impart cationic dyeability to the polyester composition, and physical crosslinking between sulfonates does not occur, the strength of the polyester composition is maintained. However, the sulfonate compound represented by the formula 2 causes an increase in the content of terminal carboxyl groups of the polyester composition, affecting the heat resistance and hydrolysis resistance of the polyester composition.

In order to solve the above problems, the polyester product obtained by the polymerization reaction is subjected to solid-phase polymerization. The functional group terminal groups of the polyester macromolecules are mainly hydroxyethyl ester and terminal carboxyl, and in the solid-phase polymerization, the hydroxyethyl ester and the hydroxyethyl ester are subjected to ester exchange reaction and esterification reaction, so that the molecular weight of the polymer can be increased, and the terminal carboxyl of the polymer can be reduced. However, since the sulfonate compound of the present invention represented by formula 2 has only one reactive group, and after copolymerization with polyester, one end of the molecular chain of polyester is blocked, the reactive group at the end is reduced, which may decrease the reaction rate of solid phase polymerization. Therefore, the invention adds alkali metal compounds except sulfonate to adjust the reaction system of the polyester composition, improves the reactivity of the end group of the polyester molecular chain, improves the solid phase polymerization reaction speed, thereby reducing the content of the end carboxyl of the final polyester composition and improving the heat resistance and hydrolysis resistance of the polymer.

The timing of adding the alkali metal compound is preferably at any stage before the completion of the polymerization reaction, and may be an esterification reaction, an ester exchange reaction, or the like. The alkali metal compound can be one or more of sodium acetate, lithium acetate, potassium acetate and cesium acetate, wherein one or more of sodium acetate, lithium acetate and potassium acetate is preferred.

The amount of the alkali metal compound added is preferably 1000ppm or less based on the total amount of the polyester composition. If the amount of the alkali metal compound added is too large, the polyester side reaction rate increases, resulting in deterioration of heat resistance of the polyester composition.

The solid-phase polymerization method of the present invention is a method of polymerizing a polyester in a solid phase under an inert gas flow or in a vacuum at a temperature not higher than the melting point of the polyester composition. The conditions for the solid-phase polymerization are not particularly limited, and any reaction conditions generally used in the art may be employed. Specifically, the polyester product obtained by the polymerization reaction is subjected to pre-crystallization treatment, and then solid-phase polymerization is performed under the conditions that the reaction temperature is 200-240 ℃, the reaction pressure is less than 1000Pa, and the reaction time is less than 100 hours, so as to obtain the final polyester composition.

The aromatic dicarboxylic acid or esterified derivative thereof of the present invention may be terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, dimethyl terephthalate, dimethyl isophthalate, dimethyl naphthalenedicarboxylate, dimethyl phthalate, etc., and among them, terephthalic acid or dimethyl terephthalate is preferable. The aliphatic diol may be ethylene glycol, propylene glycol, butylene glycol, 1, 2-propylene glycol, pentylene glycol, neopentyl glycol, 1, 2-butylene glycol, etc., among which ethylene glycol, propylene glycol or butylene glycol is preferable.

The esterification reaction may be carried out while continuously adding a slurry of an aliphatic diol and an aromatic dicarboxylic acid in a molar ratio of 1.05 to 1.50 to an esterification reaction tank in which an oligomer is present in advance; in the esterification reaction tank in which the oligomer is present in advance, the aliphatic diol and the aromatic dicarboxylic acid may be added to the reaction mixture before the esterification reaction is started, and then the esterification reaction may be performed.

The ester exchange reaction can be controlled at a proper ester exchange reaction speed by adjusting the molar ratio of the aliphatic diol to the aromatic dicarboxylic acid esterification derivative to be within the range of 1.50-2.50. The catalyst used in this process may be any of various known catalysts, for example, oxides of metals such as cobalt, magnesium, manganese and titanium, or acetates thereof, and may be used in combination or singly.

The catalyst in the polymerization reaction may be any of various known polymerization catalysts. Such as antimony compounds, germanium compounds, titanium compounds, and the like. These catalysts may be used in combination or individually.

The esterification and polymerization reaction apparatus for producing the cationic-dyeable polyester composition of the present invention, which is easy to dye, resistant to hydrolysis and high in strength, can be any of various conventionally used reaction apparatuses.

The polyester composition is easy to dye, has good hydrolysis resistance, produces less diethylene glycol and terminal carboxyl, has good strength retention rate before and after dyeing, and can be applied to fibers.

The measuring method and the evaluating method of each index of the invention are as follows:

(1) intrinsic Viscosity (IV)

0.8g of a polyester composition chip was dissolved in 10ml of an o-chlorophenol solution, and the intrinsic viscosity was measured at a water bath temperature of 25. + -. 0.2 ℃ by using an Ubbelohde viscometer.

(2) Carboxyl group Content (COOH)

The polyester chip was dissolved in a mixture of o-cresol and chloroform (70: 30 by weight), added with a bromothymol blue indicator, and then titrated with a 0.05N ethanol solution of potassium hydroxide, as measured by an optical titration method.

(3) Hydrolysis resistance index Δ COOH

Placing a certain amount of polyester granules in a sealed hydrolysis-resistant treatment system, treating for 4h under saturated water vapor condition of 155 deg.C and 100% humidity, measuring terminal carboxyl of treated sample, comparing changes of terminal carboxyl of polyester slices before and after treatment, and Δ COOH = carboxyl of treated slice-carboxyl of treated slice

(4) Analysis of Sulfur element content in polyester composition

And (4) carrying out quantitative analysis on the content of sulfur element in the polymer by an ICP element analyzer.

(5) Analysis of Sulfur element content in polyester composition

And quantitatively analyzing the content of the alkali element in the polymer by an ICP element analyzer.

(6) Evaluation of dyeing stability

The polyester composition was spun to obtain drawn yarn, the drawn yarn was then doubled by 2 pieces to obtain a leg of a stocking at 22 gauge, and the leg of the stocking was dyed in a hot water bath of 130 ℃ with a dye (blue. TR) of 3% owf, acetic acid of 0.5ml/l, sodium acetate of 0.2g/l, and a bath ratio of 1:100 for 60 minutes. The strength of the fiber before dyeing is tested to be S1, the strength of the fiber after dyeing is S2, and the strength retention rate is S2/S1. The stained sample was superposed in a light-tight state, and then subjected to CEI standard light sources D65 and 10 by a spectrophotometer (Datacolor 650 manufactured by Datacolor Asia Pacific (H.K.) Ltd.) under a CEI standard light source^oColor measurements were performed under the angular conditions to yield L.

(7) Aliphatic dicarboxylic acid structural unit content in polyester composition

A certain amount of the polyester composition was taken, and the content of the aliphatic diacid in the polyester composition was calculated from characteristic peaks of hydrogen elements (for example, hydrogen of benzene ring and hydrogen of straight chain) measured by H-NMR.

The advantages of the present invention will be described in detail below with reference to the examples and comparative examples. The present invention is not limited to the following examples.

Example 1

Terephthalic Acid (PTA) and Ethylene Glycol (EG) are mixed evenly and then put into a reaction kettle for esterification reaction at 240 ℃. After the esterification reaction is finished, transferring the reaction product into a polycondensation kettle, adding sebacic acid, antimony trioxide serving as a catalyst, trimethyl phosphate serving as a heat stabilizer and lithium acetate before polymerization reaction, and carrying out polycondensation reaction at 290 ℃. Adding ethylene glycol solution of sulfonate shown as the formula 2 after the polymerization reaction is started for 30min, and discharging and granulating after the polymer reaches the required viscosity to obtain the required polyester composition.

After the polyester product obtained by polycondensation is subjected to pre-crystallization treatment, solid-phase polymerization is carried out under the conditions of the reaction temperature of 230 ℃, the reaction pressure of 50Pa and the reaction time of 30 hours to obtain solid-phase polymerization polyester, and the intrinsic viscosity IV of the polyester composition is 0.65 dl/g.

The polyester composition was spun to obtain drawn yarn, the drawn fiber was doubled to 2 pieces, and the leg was dyed in a hot water bath of 3% owf dye (blue. TR), 0.5ml/l acetic acid, 0.2g/l sodium acetate, and a bath ratio of 1:100 at 130 ℃ for 60 minutes under 22-gauge conditions. The strength of the fiber before dyeing was tested to be S1, the strength of the fiber after dyeing was S2, the strength retention was S2/S1 to be 80%, and the L value after dyeing was 25.

Example 2

Terephthalic Acid (PTA) and Ethylene Glycol (EG) are mixed evenly and then put into a reaction kettle for esterification reaction at 240 ℃. After the esterification reaction is finished, transferring the reaction product into a polycondensation kettle, adding sebacic acid, antimony trioxide as a catalyst, trimethyl phosphate as a heat stabilizer and lithium acetate before polymerization reaction, and carrying out polycondensation reaction at 290 ℃. Adding ethylene glycol solution of sulfonate shown as the formula 2 after the polymerization reaction is started for 30min, and discharging and granulating after the polymer reaches the required viscosity to obtain the required polyester composition.

The polyester composition was spun to obtain drawn yarn, the drawn yarn was then doubled by 2 pieces to obtain a leg of a stocking at 22 gauge, and the leg of the stocking was dyed in a hot water bath of 130 ℃ with a dye (blue. TR) of 3% owf, acetic acid of 0.5ml/l, sodium acetate of 0.2g/l, and a bath ratio of 1:100 for 60 minutes. The strength of the fiber before dyeing is tested to be S1, the strength of the fiber after dyeing is S2, the strength retention rate is S2/S1 is 79%, and the L value after dyeing is 24.

Example 3

After the polyester product obtained by polycondensation is subjected to pre-crystallization treatment, solid-phase polymerization is carried out under the conditions of the reaction temperature of 230 ℃, the reaction pressure of 50Pa and the reaction time of 20 hours to obtain solid-phase polymerization polyester, and the intrinsic viscosity IV of the polyester composition is 0.66 dl/g.

The polyester composition was spun to obtain drawn yarn, the drawn yarn was then doubled by 2 pieces to obtain a leg of a stocking at 22 gauge, and the leg of the stocking was dyed in a hot water bath of 130 ℃ with a dye (blue. TR) of 3% owf, acetic acid of 0.5ml/l, sodium acetate of 0.2g/l, and a bath ratio of 1:100 for 60 minutes. The strength of the fiber before dyeing was tested to be S1, the strength of the fiber after dyeing was S2, the strength retention ratio was S2/S1 to be 82%, and the L value after dyeing was 24.

Example 4

After the polyester product obtained by polycondensation is subjected to pre-crystallization treatment, solid-phase polymerization is carried out under the conditions of the reaction temperature of 230 ℃, the reaction pressure of 50Pa and the reaction time of 40 hours to obtain solid-phase polymerization polyester, and the intrinsic viscosity IV of the polyester composition is 0.65 dl/g.

The polyester composition was spun to obtain drawn yarn, the drawn yarn was then doubled by 2 pieces to obtain a leg of a stocking at 22 gauge, and the leg of the stocking was dyed in a hot water bath of 130 ℃ with a dye (blue. TR) of 3% owf, acetic acid of 0.5ml/l, sodium acetate of 0.2g/l, and a bath ratio of 1:100 for 60 minutes. The strength of the fiber before dyeing was tested to be S1, the strength of the fiber after dyeing was S2, the strength retention was S2/S1 to be 78%, and the L value after dyeing was 25.

Example 5

After the polyester product obtained by polycondensation is subjected to pre-crystallization treatment, solid-phase polymerization is carried out under the conditions of the reaction temperature of 230 ℃, the reaction pressure of 50Pa and the reaction time of 20 hours to obtain solid-phase polymerization polyester, and the intrinsic viscosity IV of the polyester composition is 0.65 dl/g.

The polyester composition was spun to obtain drawn yarn, the drawn yarn was then doubled by 2 pieces to obtain a leg of a stocking at 22 gauge, and the leg of the stocking was dyed in a hot water bath of 130 ℃ with a dye (blue. TR) of 3% owf, acetic acid of 0.5ml/l, sodium acetate of 0.2g/l, and a bath ratio of 1:100 for 60 minutes. The strength of the fiber before dyeing was tested to be S1, the strength of the fiber after dyeing was S2, the strength retention ratio was S2/S1 was 77%, and the L value after dyeing was 24.

Example 6

Terephthalic Acid (PTA) and Ethylene Glycol (EG) are mixed evenly and then put into a reaction kettle for esterification reaction at 240 ℃. After the esterification reaction is finished, transferring the reaction product into a polycondensation kettle, adding sebacic acid, antimony trioxide serving as a catalyst, trimethyl phosphate serving as a heat stabilizer and lithium acetate before polymerization reaction, and carrying out polycondensation reaction at 290 ℃. And adding a glycol solution of sulfonate shown as the formula 2 after the polymerization reaction is started for 30min, and discharging and granulating after the polymer reaches the required viscosity to obtain the required polyester composition.

After the polyester product obtained by polycondensation is subjected to pre-crystallization treatment, solid-phase polymerization is carried out under the conditions of the reaction temperature of 230 ℃, the reaction pressure of 50Pa and the reaction time of 20 hours to obtain solid-phase polymerization polyester, and the intrinsic viscosity IV of the polyester composition is 0.64 dl/g.

The polyester composition was spun to obtain drawn yarn, the drawn yarn was then doubled by 2 pieces to obtain a leg of a stocking at 22 gauge, and the leg of the stocking was dyed in a hot water bath of 130 ℃ with a dye (blue. TR) of 3% owf, acetic acid of 0.5ml/l, sodium acetate of 0.2g/l, and a bath ratio of 1:100 for 60 minutes. The strength of the fiber before dyeing was tested to be S1, the strength of the fiber after dyeing was S2, the strength retention ratio was S2/S1 to be 75%, and the L value after dyeing was 30.

Example 7

The polyester composition was spun to obtain drawn yarn, the drawn yarn was then doubled by 2 pieces to obtain a leg of a stocking at 22 gauge, and the leg of the stocking was dyed in a hot water bath of 130 ℃ with a dye (blue. TR) of 3% owf, acetic acid of 0.5ml/l, sodium acetate of 0.2g/l, and a bath ratio of 1:100 for 60 minutes. The strength of the fiber before dyeing was tested to be S1, the strength of the fiber after dyeing was S2, the strength retention was S2/S1 to be 80%, and the L value after dyeing was 23.

Example 8

Terephthalic Acid (PTA) and Ethylene Glycol (EG) are mixed evenly and then put into a reaction kettle for esterification reaction at 240 ℃. After the esterification reaction is finished, transferring the reaction product into a polycondensation kettle, adding sebacic acid, antimony trioxide serving as a catalyst, trimethyl phosphate serving as a heat stabilizer and sodium acetate before polymerization reaction, and carrying out polycondensation reaction at 290 ℃. Adding ethylene glycol solution of sulfonate shown as the formula 2 after the polymerization reaction is started for 30min, and discharging and granulating after the polymer reaches the required viscosity to obtain the required polyester composition.

After the polyester product obtained by polycondensation is subjected to pre-crystallization treatment, solid-phase polymerization is carried out under the conditions of the reaction temperature of 230 ℃, the reaction pressure of 50Pa and the reaction time of 30 hours to obtain solid-phase polymerization polyester, and the intrinsic viscosity IV of the polyester composition is 0.64 dl/g.

The polyester composition was spun to obtain drawn yarn, the drawn yarn was then doubled by 2 pieces to obtain a leg of a stocking at 22 gauge, and the leg of the stocking was dyed in a hot water bath of 130 ℃ with a dye (blue. TR) of 3% owf, acetic acid of 0.5ml/l, sodium acetate of 0.2g/l, and a bath ratio of 1:100 for 60 minutes. The strength of the fiber before dyeing was tested to be S1, the strength of the fiber after dyeing was S2, the strength retention was S2/S1 to be 78%, and the L value after dyeing was 23.

Example 9

Terephthalic Acid (PTA) and Ethylene Glycol (EG) are mixed evenly and then put into a reaction kettle for esterification reaction at 240 ℃. After the esterification reaction is finished, transferring the reaction product into a polycondensation kettle, adding sebacic acid, antimony trioxide serving as a catalyst, trimethyl phosphate serving as a heat stabilizer and potassium acetate before polymerization reaction, and carrying out polycondensation reaction at 290 ℃. Adding ethylene glycol solution of sulfonate shown as the formula 2 after the polymerization reaction is started for 30min, and discharging and granulating after the polymer reaches the required viscosity to obtain the required polyester composition.

After the polyester product obtained by polycondensation is subjected to pre-crystallization treatment, solid-phase polymerization is carried out under the conditions of the reaction temperature of 230 ℃, the reaction pressure of 50Pa and the reaction time of 30 hours to obtain solid-phase polymerization polyester, and the intrinsic viscosity IV of the polyester composition is 0.62 dl/g.

The polyester composition was spun to obtain drawn yarn, the drawn yarn was then doubled by 2 pieces to obtain a leg of a stocking at 22 gauge, and the leg of the stocking was dyed in a hot water bath of 130 ℃ with a dye (blue. TR) of 3% owf, acetic acid of 0.5ml/l, sodium acetate of 0.2g/l, and a bath ratio of 1:100 for 60 minutes. The strength of the fiber before dyeing was tested to be S1, the strength of the fiber after dyeing was S2, the strength retention was S2/S1 to be 75%, and the L value after dyeing was 23.

Example 10

After the polyester product obtained by polycondensation is subjected to pre-crystallization treatment, solid-phase polymerization is carried out under the conditions of the reaction temperature of 230 ℃, the reaction pressure of 30Pa and the reaction time of 10 hours to obtain solid-phase polymerization polyester, and the intrinsic viscosity IV of the polyester composition is 0.64 dl/g.

The polyester composition was spun to obtain drawn yarn, the drawn yarn was then doubled by 2 pieces to obtain a leg of a stocking at 22 gauge, and the leg of the stocking was dyed in a hot water bath of 130 ℃ with a dye (blue. TR) of 3% owf, acetic acid of 0.5ml/l, sodium acetate of 0.2g/l, and a bath ratio of 1:100 for 60 minutes. The strength of the fiber before dyeing was tested to be S1, the strength of the fiber after dyeing was S2, the strength retention was S2/S1 to be 72%, and the L value after dyeing was 25.

Example 11

After the polyester product obtained by polycondensation is subjected to pre-crystallization treatment, solid-phase polymerization is carried out under the conditions of the reaction temperature of 230 ℃, the reaction pressure of 30Pa and the reaction time of 30 hours to obtain solid-phase polymerization polyester, and the intrinsic viscosity IV of the polyester composition is 0.65 dl/g.

The polyester composition was spun to obtain drawn yarn, the drawn yarn was then doubled by 2 pieces to obtain a leg of a stocking at 22 gauge, and the leg of the stocking was dyed in a hot water bath of 130 ℃ with a dye (blue. TR) of 3% owf, acetic acid of 0.5ml/l, sodium acetate of 0.2g/l, and a bath ratio of 1:100 for 60 minutes. The strength of the fiber before dyeing was tested to be S1, the strength of the fiber after dyeing was S2, the strength retention was S2/S1 to be 74%, and the L value after dyeing was 23.

Example 12

After the polyester product obtained by polycondensation is subjected to pre-crystallization treatment, solid-phase polymerization is carried out under the conditions of the reaction temperature of 230 ℃, the reaction pressure of 20Pa and the reaction time of 30 hours to obtain solid-phase polymerization polyester, and the intrinsic viscosity IV of the polyester composition is 0.62 dl/g.

The polyester composition was spun to obtain drawn yarn, the drawn yarn was then doubled by 2 pieces to obtain a leg of a stocking at 22 gauge, and the leg of the stocking was dyed in a hot water bath of 130 ℃ with a dye (blue. TR) of 3% owf, acetic acid of 0.5ml/l, sodium acetate of 0.2g/l, and a bath ratio of 1:100 for 60 minutes. The strength of the fiber before dyeing was tested to be S1, the strength of the fiber after dyeing was S2, the strength retention was S2/S1 to be 70%, and the L value after dyeing was 25.

Example 13

Terephthalic Acid (PTA) and Ethylene Glycol (EG) are mixed evenly and then put into a reaction kettle for esterification reaction at 240 ℃. After the esterification reaction is finished, transferring the reaction product into a polycondensation kettle, adding succinic acid, antimony trioxide as a catalyst, trimethyl phosphate as a heat stabilizer and lithium acetate before polymerization reaction, and carrying out polycondensation reaction at 290 ℃. And adding a glycol solution of sulfonate shown as a formula 2 after 10min from the beginning of the polymerization reaction, and spitting and granulating after the polymer reaches the required viscosity to obtain the required polyester composition.

After the polyester product obtained by polycondensation is subjected to pre-crystallization treatment, solid-phase polymerization is carried out under the conditions of the reaction temperature of 230 ℃, the reaction pressure of 30Pa and the reaction time of 30 hours to obtain solid-phase polymerization polyester, and the intrinsic viscosity IV of the polyester composition is 0.63 dl/g.

The polyester composition was spun to obtain drawn yarn, the drawn yarn was then doubled by 2 pieces to obtain a leg of a stocking at 22 gauge, and the leg of the stocking was dyed in a hot water bath of 130 ℃ with a dye (blue. TR) of 3% owf, acetic acid of 0.5ml/l, sodium acetate of 0.2g/l, and a bath ratio of 1:100 for 60 minutes. The strength of the fiber before dyeing was tested to be S1, the strength of the fiber after dyeing was S2, the strength retention ratio was S2/S1 to be 71%, and the L value after dyeing was 25.

Example 14

After the polyester product obtained by polycondensation is subjected to pre-crystallization treatment, solid-phase polymerization is carried out under the conditions that the reaction temperature is 230 ℃, the reaction pressure is 30Pa and the reaction time is 30 hours to obtain solid-phase polymerization polyester, wherein the intrinsic viscosity IV of the polyester composition is 0.63 dl/g.

The polyester composition was spun to obtain drawn yarn, the drawn yarn was then doubled by 2 pieces to obtain a leg of a stocking at 22 gauge, and the leg of the stocking was dyed in a hot water bath of 130 ℃ with a dye (blue. TR) of 3% owf, acetic acid of 0.5ml/l, sodium acetate of 0.2g/l, and a bath ratio of 1:100 for 60 minutes. The strength of the fiber before dyeing was tested to be S1, the strength of the fiber after dyeing was tested to be S2, the strength retention ratio was S2/S1 to be 75%, and the L value after dyeing was 24.

Example 15

Terephthalic Acid (PTA) and Ethylene Glycol (EG) are mixed evenly and then put into a reaction kettle for esterification reaction at 240 ℃. After the esterification reaction is finished, transferring the reaction product into a polycondensation kettle, adding succinic acid, antimony trioxide as a catalyst, trimethyl phosphate as a heat stabilizer and lithium acetate before polymerization reaction, and carrying out polycondensation reaction at 290 ℃. And adding a glycol solution of sulfonate shown as the formula 2 after 10min from the beginning of the polymerization reaction, and spitting and granulating after the polymer reaches the required viscosity to obtain the required polyester composition.

The polyester composition was spun to obtain drawn yarn, the drawn yarn was then doubled by 2 pieces to obtain a leg of a stocking at 22 gauge, and the leg of the stocking was dyed in a hot water bath of 130 ℃ with a dye (blue. TR) of 3% owf, acetic acid of 0.5ml/l, sodium acetate of 0.2g/l, and a bath ratio of 1:100 for 60 minutes. The strength of the fiber before dyeing was tested to be S1, the strength of the fiber after dyeing was S2, the strength retention ratio was S2/S1 was 68%, and the L value after dyeing was 26.

Example 16

Terephthalic Acid (PTA) and Ethylene Glycol (EG) are mixed evenly and then put into a reaction kettle for esterification reaction at 240 ℃. After the esterification reaction is finished, transferring the reaction product into a polycondensation kettle, adding succinic acid, a catalyst antimony trioxide, a heat stabilizer trimethyl phosphate and lithium acetate before polymerization reaction, and carrying out polycondensation reaction at 290 ℃. And adding a glycol solution of sulfonate shown as a formula 2 after 10min from the beginning of the polymerization reaction, and spitting and granulating after the polymer reaches the required viscosity to obtain the required polyester composition.

The polyester composition was spun to obtain drawn yarn, the drawn yarn was then doubled by 2 pieces to obtain a leg of a stocking at 22 gauge, and the leg of the stocking was dyed in a hot water bath of 130 ℃ with a dye (blue. TR) of 3% owf, acetic acid of 0.5ml/l, sodium acetate of 0.2g/l, and a bath ratio of 1:100 for 60 minutes. The strength of the fiber before dyeing was tested to be S1, the strength of the fiber after dyeing was S2, the strength retention was S2/S1 to be 70%, and the L value after dyeing was 23.

Example 17

Terephthalic Acid (PTA) and Ethylene Glycol (EG) are mixed evenly and then put into a reaction kettle for esterification reaction at 240 ℃. After the esterification reaction is finished, transferring the reaction product into a polycondensation kettle, adding succinic acid, antimony trioxide as a catalyst, trimethyl phosphate as a heat stabilizer and lithium acetate before polymerization reaction, and carrying out polycondensation reaction at 290 ℃. And adding a solution of sulfonate shown as a formula 2 after 10min from the beginning of the polymerization reaction, and spitting and granulating after the polymer reaches the required viscosity to obtain the required polyester composition.

After the polyester product obtained by polycondensation is subjected to pre-crystallization treatment, solid-phase polymerization is carried out under the conditions of the reaction temperature of 230 ℃, the reaction pressure of 30Pa and the reaction time of 30 hours to obtain solid-phase polymerization polyester, and the intrinsic viscosity IV of the polyester composition is 0.60 dl/g.

The polyester composition was spun to obtain drawn yarn, the drawn fiber was doubled to 2 pieces, and the leg was dyed in a hot water bath of 3% owf dye (blue. TR), 0.5ml/l acetic acid, 0.2g/l sodium acetate, and a bath ratio of 1:100 at 130 ℃ for 60 minutes under 22-gauge conditions. The strength of the fiber before dyeing was tested to be S1, the strength of the fiber after dyeing was S2, the strength retention was S2/S1 to be 70%, and the L value after dyeing was 25.

Example 18

Uniformly mixing terephthalic acid (PTA), Ethylene Glycol (EG) and sulfonate shown as a formula 2, putting the mixture into a reaction kettle, and carrying out esterification reaction at 240 ℃. After the esterification reaction is finished, transferring the reaction product into a polycondensation kettle, adding succinic acid, antimony trioxide as a catalyst, trimethyl phosphate as a heat stabilizer and lithium acetate before polymerization reaction, and carrying out polycondensation reaction at 290 ℃. And (3) after the polymer reaches the required viscosity, discharging and granulating to obtain the required polyester composition.

The polyester composition was spun to obtain drawn yarn, the drawn yarn was then doubled by 2 pieces to obtain a leg of a stocking at 22 gauge, and the leg of the stocking was dyed in a hot water bath of 130 ℃ with a dye (blue. TR) of 3% owf, acetic acid of 0.5ml/l, sodium acetate of 0.2g/l, and a bath ratio of 1:100 for 60 minutes. The strength of the fiber before dyeing was tested to be S1, the strength of the fiber after dyeing was S2, the strength retention was S2/S1 to be 68%, and the L value after dyeing was 25.

Example 19

Terephthalic Acid (PTA) and Ethylene Glycol (EG) are mixed evenly and then put into a reaction kettle for esterification reaction at 240 ℃. After the esterification reaction is finished, transferring the reaction product into a polycondensation kettle, adding succinic acid, antimony trioxide as a catalyst, trimethyl phosphate as a heat stabilizer and lithium acetate before polymerization reaction, and carrying out polycondensation reaction at 290 ℃. And adding a glycol solution of sulfonate shown as the formula 2 after the polymerization reaction is started for 30min, and discharging and granulating after the polymer reaches the required viscosity to obtain the required polyester composition.

The polyester composition was spun to obtain drawn yarn, the drawn yarn was then doubled by 2 pieces to obtain a leg of a stocking at 22 gauge, and the leg of the stocking was dyed in a hot water bath of 130 ℃ with a dye (blue. TR) of 3% owf, acetic acid of 0.5ml/l, sodium acetate of 0.2g/l, and a bath ratio of 1:100 for 60 minutes. The strength of the fiber before dyeing was tested to be S1, the strength of the fiber after dyeing was S2, the strength retention was S2/S1 to be 78%, and the L value after dyeing was 27.

Example 20

Terephthalic Acid (PTA) and Ethylene Glycol (EG) are mixed evenly and then put into a reaction kettle for esterification reaction at 240 ℃. After the esterification reaction is finished, transferring the reaction product into a polycondensation kettle, adding succinic acid, antimony trioxide as a catalyst, trimethyl phosphate as a heat stabilizer and lithium acetate before polymerization reaction, and carrying out polycondensation reaction at 290 ℃. Adding ethylene glycol solution of sulfonate shown as the formula 2 after the polymerization reaction is started for 30min, and discharging and granulating after the polymer reaches the required viscosity to obtain the required polyester composition.

The polyester composition was spun to obtain drawn yarn, the drawn yarn was then doubled by 2 pieces to obtain a leg of a stocking at 22 gauge, and the leg of the stocking was dyed in a hot water bath of 130 ℃ with a dye (blue. TR) of 3% owf, acetic acid of 0.5ml/l, sodium acetate of 0.2g/l, and a bath ratio of 1:100 for 60 minutes. The strength of the fiber before dyeing was tested to be S1, the strength of the fiber after dyeing was S2, the strength retention ratio was S2/S1 to be 80%, and the L value after dyeing was 22.

Example 21

The polyester composition was spun to obtain drawn yarn, the drawn yarn was then doubled by 2 pieces to obtain a leg of a stocking at 22 gauge, and the leg of the stocking was dyed in a hot water bath of 130 ℃ with a dye (blue. TR) of 3% owf, acetic acid of 0.5ml/l, sodium acetate of 0.2g/l, and a bath ratio of 1:100 for 60 minutes. The strength of the fiber before dyeing is tested to be S1, the strength of the fiber after dyeing is S2, the strength retention rate is S2/S1 is 79%, and the L value after dyeing is 26.

Example 22

After the polyester product obtained by polycondensation is subjected to pre-crystallization treatment, solid-phase polymerization is carried out under the conditions of the reaction temperature of 230 ℃, the reaction pressure of 50Pa and the reaction time of 20 hours to obtain solid-phase polymerization polyester, and the intrinsic viscosity IV of the polyester composition is 0.67 dl/g.

The polyester composition was spun to obtain drawn yarn, the drawn fiber was doubled to 2 pieces, and the leg was dyed in a hot water bath of 3% owf dye (blue. TR), 0.5ml/l acetic acid, 0.2g/l sodium acetate, and a bath ratio of 1:100 at 130 ℃ for 60 minutes under 22-gauge conditions. The strength of the fiber before dyeing was tested to be S1, the strength of the fiber after dyeing was S2, the strength retention ratio was S2/S1 to be 81%, and the L value after dyeing was 22.

Example 23

After the polyester product obtained by polycondensation is subjected to pre-crystallization treatment, solid-phase polymerization is carried out under the conditions of the reaction temperature of 230 ℃, the reaction pressure of 50Pa and the reaction time of 20 hours to obtain solid-phase polymerization polyester, and the intrinsic viscosity IV of the polyester composition is 0.68 dl/g.

The polyester composition was spun to obtain drawn yarn, the drawn yarn was then doubled by 2 pieces to obtain a leg of a stocking at 22 gauge, and the leg of the stocking was dyed in a hot water bath of 130 ℃ with a dye (blue. TR) of 3% owf, acetic acid of 0.5ml/l, sodium acetate of 0.2g/l, and a bath ratio of 1:100 for 60 minutes. The strength of the fiber before dyeing was tested to be S1, the strength of the fiber after dyeing was S2, the strength retention ratio was S2/S1 to be 82%, and the L value after dyeing was 22.

Example 24

After the polyester product obtained by polycondensation is subjected to pre-crystallization treatment, solid-phase polymerization is carried out under the conditions that the reaction temperature is 230 ℃, the reaction pressure is 50Pa and the reaction time is 20 hours to obtain solid-phase polymerization polyester, wherein the intrinsic viscosity IV of the polyester composition is 0.63 dl/g.

The polyester composition was spun to obtain drawn yarn, the drawn yarn was then doubled by 2 pieces to obtain a leg of a stocking at 22 gauge, and the leg of the stocking was dyed in a hot water bath of 130 ℃ with a dye (blue. TR) of 3% owf, acetic acid of 0.5ml/l, sodium acetate of 0.2g/l, and a bath ratio of 1:100 for 60 minutes. The strength of the fiber before dyeing was tested to be S1, the strength of the fiber after dyeing was S2, the strength retention ratio was S2/S1 to be 68%, and the L value after dyeing was 22.

Example 25

The polyester composition was spun to obtain drawn yarn, the drawn yarn was then doubled by 2 pieces to obtain a leg of a stocking at 22 gauge, and the leg of the stocking was dyed in a hot water bath of 130 ℃ with a dye (blue. TR) of 3% owf, acetic acid of 0.5ml/l, sodium acetate of 0.2g/l, and a bath ratio of 1:100 for 60 minutes. The strength of the fiber before dyeing was tested to be S1, the strength of the fiber after dyeing was S2, the strength retention ratio was S2/S1 to be 75%, and the L value after dyeing was 24.

Comparative example 1

The polyester composition was spun to obtain drawn yarn, the drawn yarn was then doubled by 2 pieces to obtain a leg of a stocking at 22 gauge, and the leg of the stocking was dyed in a hot water bath of 130 ℃ with a dye (blue. TR) of 3% owf, acetic acid of 0.5ml/l, sodium acetate of 0.2g/l, and a bath ratio of 1:100 for 60 minutes. The strength of the fiber before dyeing was tested to be S1, the strength of the fiber after dyeing was S2, the strength retention was S2/S1 to be 60%, and the L value after dyeing was 25.

Since no solid phase polymerization was carried out, the polyester composition had a low IV and a high COOH, and the strength retention before and after dyeing was poor.

Comparative example 2

Terephthalic Acid (PTA) and Ethylene Glycol (EG) are mixed evenly and then put into a reaction kettle for esterification reaction at 240 ℃. After the esterification reaction is finished, transferring the reaction product into a polycondensation kettle, adding sebacic acid, antimony trioxide serving as a catalyst and trimethyl phosphate serving as a heat stabilizer before polymerization reaction, and carrying out polycondensation reaction at 290 ℃. Adding ethylene glycol solution of sulfonate shown as the formula 2 after the polymerization reaction is started for 30min, and discharging and granulating after the polymer reaches the required viscosity to obtain the required polyester composition.

The polyester composition was spun to obtain drawn yarn, the drawn yarn was then doubled by 2 pieces to obtain a leg of a stocking at 22 gauge, and the leg of the stocking was dyed in a hot water bath of 130 ℃ with a dye (blue. TR) of 3% owf, acetic acid of 0.5ml/l, sodium acetate of 0.2g/l, and a bath ratio of 1:100 for 60 minutes. The strength of the fiber before dyeing was tested to be S1, the strength of the fiber after dyeing was S2, the strength retention ratio was S2/S1 to be 50%, and the L value after dyeing was 25.

Since no solid phase polymerization is carried out, and no alkali metal salt is added, the polyester composition has a low IV and a high COOH content, and the strength retention before and after dyeing is poor.

Comparative example 3

After the polyester product obtained by polycondensation is subjected to pre-crystallization treatment, solid-phase polymerization is carried out under the conditions of the reaction temperature of 230 ℃, the reaction pressure of 50Pa and the reaction time of 20 hours to obtain solid-phase polymerization polyester, and the intrinsic viscosity IV of the polyester composition is 0.56 dl/g.

The polyester composition was spun to obtain drawn yarn, the drawn yarn was then doubled by 2 pieces to obtain a leg of a stocking at 22 gauge, and the leg of the stocking was dyed in a hot water bath of 130 ℃ with a dye (blue. TR) of 3% owf, acetic acid of 0.5ml/l, sodium acetate of 0.2g/l, and a bath ratio of 1:100 for 60 minutes. The strength of the fiber before dyeing was tested to be S1, the strength of the fiber after dyeing was S2, the strength retention was S2/S1 to be 59%, and the L value after dyeing was 25.

Although solid-phase polymerization was carried out, the polyester composition had a low IV and a high COOH content because no alkali metal salt was added, and the strength retention before and after dyeing was poor.

Comparative example 4

Terephthalic Acid (PTA) and Ethylene Glycol (EG) are mixed evenly and then put into a reaction kettle for esterification reaction at 240 ℃. After the esterification reaction is finished, transferring the reaction product into a polycondensation kettle, adding sebacic acid, antimony trioxide serving as a catalyst, trimethyl phosphate serving as a heat stabilizer and lithium acetate before polymerization reaction, and carrying out polycondensation reaction at 290 ℃. Adding m-phthalic acid-5-sodium sulfonate 30min after the polymerization reaction begins, and discharging and granulating after the polymer reaches the required viscosity to obtain the required polyester composition.

After the polyester product obtained by polycondensation is subjected to pre-crystallization treatment, solid-phase polymerization is carried out under the conditions of the reaction temperature of 230 ℃, the reaction pressure of 50Pa and the reaction time of 10 hours to obtain solid-phase polymerization polyester, and the intrinsic viscosity IV of the polyester composition is 0.59 dl/g.

The polyester composition was spun to obtain drawn yarn, the drawn yarn was then doubled by 2 pieces to obtain a leg of a stocking at 22 gauge, and the leg of the stocking was dyed in a hot water bath of 130 ℃ with a dye (blue. TR) of 3% owf, acetic acid of 0.5ml/l, sodium acetate of 0.2g/l, and a bath ratio of 1:100 for 60 minutes. The strength of the fiber before dyeing was tested to be S1, the strength of the fiber after dyeing was S2, the strength retention was S2/S1 to be 65%, and the L value after dyeing was 25.

Because the added sulfonate is sodium m-phthalic acid-5-sulfonate, the polyester composition has low IV, high COOH and poor strength retention rate before and after dyeing.

Comparative example 5

The polyester composition was spun to obtain drawn yarn, the drawn yarn was then doubled by 2 pieces to obtain a leg of a stocking at 22 gauge, and the leg of the stocking was dyed in a hot water bath of 130 ℃ with a dye (blue. TR) of 3% owf, acetic acid of 0.5ml/l, sodium acetate of 0.2g/l, and a bath ratio of 1:100 for 60 minutes. The strength of the fiber before dyeing was tested to be S1, the strength of the fiber after dyeing was S2, the strength retention was S2/S1 to be 80%, and the L value after dyeing was 45.

The amount of the sulfonate to be added is too low, the dyeability of the polyester composition is poor, and the L value is high.

Comparative example 6

After the polyester product obtained by polycondensation is subjected to pre-crystallization treatment, solid-phase polymerization is carried out under the conditions of the reaction temperature of 230 ℃, the reaction pressure of 50Pa and the reaction time of 20 hours to obtain solid-phase polymerization polyester, and the intrinsic viscosity IV of the polyester composition is 0.55 dl/g.

The polyester composition was spun to obtain drawn yarn, the drawn yarn was then doubled by 2 pieces to obtain a leg of a stocking at 22 gauge, and the leg of the stocking was dyed in a hot water bath of 130 ℃ with a dye (blue. TR) of 3% owf, acetic acid of 0.5ml/l, sodium acetate of 0.2g/l, and a bath ratio of 1:100 for 60 minutes. The strength of the fiber before dyeing is tested to be S1, the strength of the fiber after dyeing is S2, the strength retention rate is S2/S1 is 58%, and the L value after dyeing is 22.

The amount of the sulfonate to be added is too high, the IV of the polyester composition is low, COOH is high, and the strength retention before and after dyeing is poor.

Comparative example 7

Terephthalic Acid (PTA) and Ethylene Glycol (EG) are mixed evenly and then put into a reaction kettle for esterification reaction at 240 ℃. After the esterification reaction is finished, transferring the reaction product into a polycondensation kettle, adding catalyst antimony trioxide, heat stabilizer trimethyl phosphate and lithium acetate, and carrying out polycondensation reaction at 290 ℃. Adding ethylene glycol solution of sulfonate shown as the formula 2 after the polymerization reaction is started for 30min, and discharging and granulating after the polymer reaches the required viscosity to obtain the required polyester composition.

The polyester composition was spun to obtain drawn yarn, the drawn fiber was doubled to 2 pieces, and the leg was dyed in a hot water bath of 3% owf dye (blue. TR), 0.5ml/l acetic acid, 0.2g/l sodium acetate, and a bath ratio of 1:100 at 130 ℃ for 60 minutes under 22-gauge conditions. The strength of the fiber before dyeing was tested to be S1, the strength of the fiber after dyeing was S2, the strength retention was S2/S1 to be 65%, and the L value after dyeing was 29.

Since the aliphatic dicarboxylic acid or an esterified derivative thereof is not added, the color tone after dyeing and the strength retention ratio before and after dyeing of the polyester composition are not good.

Claims

1. The cationic dyeable polyester composition is mainly composed of an aromatic dicarboxylic acid structural unit and an aliphatic diol structural unit, and is characterized in that: the polyester composition contains a sulfonate group shown as a formula 1, and the content of the group shown as the formula 1 accounts for 1000-5000 ppm of the total amount of the polyester composition in terms of sulfur element; the polyester composition contains aliphatic dicarboxylic acid structural units;

in the formula 1, the compound is shown in the specification,

2. The cationic dyeable polyester composition of claim 1, wherein: the number of carbon atoms in the aliphatic dicarboxylic acid structural unit is 4-10, and the aliphatic dicarboxylic acid structural unit accounts for 0.1-10.0 wt% of the total weight of the polyester composition.

3. The cationic dyeable polyester composition of claim 1 or 2, characterized by: the molar ratio of the alkali metal element to the sulfur element in the polyester composition is more than 1.00.

4. The cationic dyeable polyester composition of claim 1 or 2, characterized by: the content of the group shown in the formula 1 is 1000-3500 ppm of the total amount of the polyester composition calculated by sulfur element.

5. The cationic dyeable polyester composition of claim 1 or 2, characterized by: the polyester composition has a hydrolysis resistance index delta COOH of less than 80eq/t after being treated for 4 hours under saturated water vapor at 155 ℃ and 100% humidity.

6. The process for preparing a cationic dyeable polyester composition according to claim 1, comprising the steps of subjecting an aromatic dicarboxylic acid or an esterified derivative thereof and an aliphatic diol to esterification or transesterification to obtain an oligomer, polymerizing the oligomer, and finally subjecting the oligomer to solid-phase polymerization to obtain a polyester composition, wherein: adding a sulfonate compound shown as a formula 2 and aliphatic dicarboxylic acid or an esterified derivative thereof at any stage before the polymerization reaction is finished; the addition amount of the sulfonate compound shown as the formula 2 is 1000-5000 ppm relative to the total amount of the polyester composition in terms of sulfur element,

in the formula (2), the first and second groups,

7. The process for preparing a cationic dyeable polyester composition according to claim 6, wherein: the number of carbon atoms of the aliphatic dicarboxylic acid is 4-10, and the addition amount of the aliphatic dicarboxylic acid or the esterified derivative thereof is 0.1-10.0 wt% of the total amount of the polyester composition.

8. The process for the preparation of the cationic dyeable polyester composition according to claim 6 or 7, characterized in that: the addition amount of the sulfonate shown in the formula 2 is 1000-3500 ppm relative to the total amount of the polyester composition in terms of sulfur element.

9. The process for the preparation of the cationic dyeable polyester composition according to claim 6 or 7, characterized in that: the alkali metal compound is added at an arbitrary stage before the completion of the polymerization reaction, and the amount of the alkali metal compound added is 1000ppm or less based on the total amount of the polyester composition.

10. The process for the preparation of the cationic dyeable polyester composition according to claim 6 or 7, characterized in that: the sulfonate compound is added 20min to 60min after the start of polymerization.

11. The process for the preparation of the cationic dyeable polyester composition according to claim 6 or 7, characterized in that: the reaction temperature of the solid-phase polymerization is 200-240 ℃, the reaction pressure is below 1000Pa, and the reaction time is below 100 hours.

12. The process for the preparation of the cationic dyeable polyester composition according to claim 6 or 7, characterized in that: the alkali metal compound is one or more of sodium acetate, lithium acetate and potassium acetate.

13. Use of the cationic dyeable polyester composition of claim 1 in fibers.