Degradable polyester fiber and preparing method thereof

Abstract

A type of degradable polyester fiber and preparing method thereof are disclosed. The preparing method is to melt spinning a modified polyester with the fully drawn yarn (FDY) technique, and the modified polyester is composed of the terephthalic acid segments, the ethylene glycol segments, the 2,5,6,6-tetramethyl-2,5-heptanediol segments and the fluorinated dicarboxylic acid segments, wherein the fluorinated dicarboxylic acid is one selected from 2,2-difluoro-1,3-malonic acid, 2,2-difluoro-1,4-succinic acid, 2,2-difluoro-1,5-glutaric acid and 2,2,3,3-tetrafluoro-1,4-succinic acid. Moreover, the modified polyester is dispersed with the doped ZrO.sub.2 powder. The obtain fiber has an intrinsic viscosity drop of 23-28% when stored at 25° C. and R.H. 65% for 60 months. The method herein is of low cost and easy technologies, whereas the obtained fiber has a rapid natural degradation rate and a wide application prospect.

Claims

1. A preparing method for a degradable polyester fiber, comprising: manufacturing a fully drawn yarn (FDY) with a modified polyester; wherein the modified polyester is a product of an esterification and a successive polycondensation of evenly mixed terephthalic acid, ethylene glycol, 2,5,6,6-tetramethyl-2,5-heptanediol, a doped ZrO.sub.2 powder and a fluorinated dicarboxylic acid; wherein the 2,5,6,6-tetramethyl-2,5-heptanediol has a molecular formula of ##STR00004## wherein the fluorinated dicarboxylic acid is selected from the group consisting of 2,2-difluoro-1,3-malonic acid, 2,2-difluoro-1,4-succinic acid, 2,2-difluoro-1,5-glutaric acid and 2,2,3,3-tetrafluoro-1,4-succinic acid; wherein the doped ZrO.sub.2 powder is obtained through a process of evenly mixing a M.sup.x+ solution and a Zr.sup.4+ solution at first, then dripping in a precipitant until a pH value is 9-10, and finally calcining the precipitate; wherein M.sup.x+ is more than one ion selected from the group consisting of Mg.sup.2+, Li.sup.+ and Zn.sup.2+; wherein a solution blending before a coprecipitation is to make a mixture containing (5-8):100 (molar ratio) of M.sup.x+ respecting to Zr.sup.4+; wherein an addition of the doped ZrO.sub.2 powder is 0.23-0.25 wt %, being relative to an amount of the terephthalic acid.

2. The preparing method of claim 1, wherein the 2,5,6,6-tetramethyl-2,5-heptanediol is synthesized by the steps of: (1) mixing KOH, 3-methyl-3-hydroxybutyne, 3,3-dimethyl-2-butanone and isopropyl ether in a molar ratio of (1-1.2):1:(1.2-1.3):(2.0-3.0), then carrying out a first reaction in an ice bath for 2-4 hr, finally obtaining heptynediol through a series of processes of cooling crystallization, centrifugation, washing, refining and drying; (2) mixing the heptynediol, an alcohol and a Pd catalyst in a weight ratio of (2-3):10:(0.01-0.03), then carrying out a second reaction accompanied with a continuous hydrogen input at 40-50° C. for 50-60 min, finally obtaining the 2,5,6,6-tetramethyl-2,5-heptanediol through a series of processes of separation and purification.

3. The preparing method of claim 2, wherein the M.sup.x+ solution is an aqueous solution with a concentration of 1-2 wt % and an anion is NO.sub.3.sup.−; wherein the Zr.sup.4+ solution is a product of dissolving 20-25 wt % of ZrO.sub.2 in nitric acid; wherein the precipitant is ammonia water with a concentration of 2 mol/L; wherein the calcining is preceded by a washing process and a drying process for the precipitate, and the drying process is carried out at a temperature of 105-110° C. for 2-3 hr; wherein the calcining includes steps of a 400° C. heating for 2-3_hr, a 700° C. heating for 1-2 hr, a cooling in air and a grinding to obtain particles with an average size of less than 0.5 μm.

4. The preparing method of claim 3, wherein the modified polyester is manufactured through the following steps: (1) the esterification concocting the terephthalic acid, the ethylene glycol, the 2,5,6,6-tetramethyl-2,5-heptanediol and the fluorinated dicarboxylic acid into a slurry, then adding in the doped ZrO.sub.2 powder, a catalyst, a matting agent and a stabilizer and carrying out the esterification in a nitrogen atmosphere with a pressure of normal value-0.3 MPa at 250-260° C., finally ending the esterification when a water distillation reaches more than 90% of a theoretical value; (2) polycondensation for products of the esterification, reducing the pressure to less than 500 Pa (absolute value) within 30-50 min and carrying out the polycondensation at 250-260° C. for 30-50 min, successively, further reducing the pressure to less than 100 Pa (absolute value) and continuing the polycondensation at 270-282° C. for 50-90 min.

5. The preparing method of claim 4, wherein a molar ratio of the terephthalic acid and the ethylene glycol is 1:(1.2-2.0), and being relative to the amount of the terephthalic acid, a total addition of the 2,5,6,6-tetramethyl-2,5-heptanediol and the fluorinated dicarboxylic acid (in a molar ratio of (1-2):(1-2)) is 4-6 mol %, whereas an addition of the catalyst, the matting agent and the stabilizer are 0.03-0.05 wt %, 0.2-0.25 wt % and 0.01-0.05 wt %, respectively.

6. The preparing method of claim 5, wherein the catalyst is selected from the group consisting of antimony trioxide, ethylene glycol antimony and antimony acetate, wherein the matting agent is titanium dioxide, and wherein the stabilizer is selected from the group consisting of triphenyl phosphate, trimethyl phosphate and trimethyl phosphite.

7. The preparing method claim 6, wherein the modified polyester has a molecular weight of 25000-30000 and a molecular weight distribution index of 1.8-2.2.

8. The preparing method of claim 1, wherein a FDY process to manufacture the FDY comprises steps of metering, spinneret extruding, cooling, oiling, stretching, heat setting and winding; wherein the FDY process involves technological parameters: a spinning temperature of 285-295° C., a cooling temperature of 19-22° C., an interlacing pressure of 0.20-0.30 MPa, a godet roller 1 speed of 2300-2700 m/ min, a godet roller 1 temperature of 80-90° C., a godet roller 2 speed of 3800-4200 m/min, a godet roller 2 temperature of 115-130° C., and a winding speed of 3730-4120 m/min.

9. A degradable polyester fiber prepared by the preparing method of claim 1, comprising: a modified polyester FDY; wherein the modified polyester has a molecular chain structure composed of terephthalic acid segments, ethylene glycol segments, 2,5,6,6-tetramethyl-2,5-heptanediol segments and fluorinated dicarboxylic acid segments; wherein the modified polyester is also dispersed with the doped ZrO.sub.2 powder obtained through the process of evenly mixing the M.sup.x+ solution and the Zr.sup.4+ solution at first, then dripping in the precipitant until the pH value is 9-10, and finally calcining the precipitate; wherein the M.sup.x+ is more than one ion selected from the group consisting of Mg.sup.2+, Li.sup.+ and Zn.sup.2+.

10. The degradable polyester fiber of claim 9, wherein the degradable polyester fiber comprises mechanical performance indices: a monofilament fineness of 1.0-2.0 dtex, a breaking strength ≥3.0 cN/dtex, an elongation at break of 32.0±4.0%, an interlacing degree of 13±2/m, a linear density deviation rate ≤1.0%, a breaking strength CV value ≤5.0%, a breaking elongation CV value ≤9.0%, a boiling water shrinkage rate of 6.5±0.5%, an intrinsic viscosity drop of 23-28% after a storage at 25° C. and a R.H. 65% for 60 months.

11. The degradable polyester fiber of claim 9, wherein the 2,5,6,6-tetramethyl-2,5-heptanediol is synthesized by the steps of: (1) mixing KOH, 3-methyl-3-hydroxybutyne, 3,3-dimethyl-2-butanone and isopropyl ether in a molar ratio of (1-1.2):1:(1.2-1.3):(2.0-3.0), then carrying out a first reaction in an ice bath for 2-4 hr, finally obtaining heptynediol through a series of processes of cooling crystallization, centrifugation, washing, refining and drying; (2) mixing the heptynediol, an alcohol and a Pd catalyst in a weight ratio of (2-3):10:(0.01-0.03), then carrying out a second reaction accompanied with a continuous hydrogen input at 40-50° C. for 50-60 min, finally obtaining the 2,5,6,6-tetramethyl-2,5-heptanediol through a series of processes of separation and purification.

12. The degradable polyester fiber of claim 11, wherein the M.sup.x+ solution is an aqueous solution with a concentration of 1-2 wt % and an anion is NO.sub.3.sup.−; wherein the Zr.sup.4+ solution is a product of dissolving 20-25 wt % of ZrO.sub.2 in nitric acid; wherein the precipitant is ammonia water with a concentration of 2 mol/L; wherein the calcining is preceded by a washing process and a drying process for the precipitate, and the drying process is carried out at a temperature of 105-110° C. for 2-3 hr; wherein the calcining includes steps of a 400° C. heating for 2-3_hr, a 700° C. heating for 1-2 hr, a cooling in air and a grinding to obtain particles with an average size of less than 0.5 μm.

13. The degradable polyester fiber of claim 12, wherein the modified polyester is manufactured through the following steps: (1) the esterification concocting the terephthalic acid, the ethylene glycol, the 2,5,6,6-tetramethyl-2,5-heptanediol and the fluorinated dicarboxylic acid into a slurry, then adding in the doped ZrO.sub.2 powder, a catalyst, a matting agent and a stabilizer and carrying out the esterification in a nitrogen atmosphere with a pressure of normal value-0.3 MPa at 250-260° C., finally ending the esterification when a water distillation reaches more than 90% of a theoretical value; (2) polycondensation for products of the esterification, reducing the pressure to less than 500 Pa (absolute value) within 30-50 min and carrying out the polycondensation at 250-260 ° C. for 30-50 min, successively, further reducing the pressure to less than an absolute value of 100 Pa (absolute value) and continuing the polycondensation at 270-282 ° C. for 50-90 min.

14. The degradable polyester fiber of claim 13, wherein a molar ratio of the terephthalic acid and the ethylene glycol is 1:(1.2-2.0), and being relative to the amount of the terephthalic acid, a total addition of the 2,5,6,6-tetramethyl-2,5-heptanediol and the fluorinated dicarboxylic acid (in a molar ratio of (1-2):(1-2)) is 4-6 mol %, whereas an addition of the catalyst, the matting agent and the stabilizer are 0.03-0.05 wt %, 0.2-0.25 wt % and 0.01-0.05 wt %, respectively.

15. The degradable polyester fiber of claim 14, wherein the catalyst is selected from the group consisting of antimony trioxide, ethylene glycol antimony and antimony acetate, wherein the matting agent is titanium dioxide, and wherein the stabilizer is selected from the group consisting of triphenyl phosphate, trimethyl phosphate and trimethyl phosphite.

16. The degradable polyester fiber of claim 15, wherein the modified polyester has a molecular weight of 25000-30000 and a molecular weight distribution index of 1.8-2.2.

17. The degradable polyester fiber of claim 9, wherein a FDY process to manufacture the FDY comprises steps of metering, spinneret extruding, cooling, oiling, stretching, heat setting and winding; wherein the FDY process involves technological parameters: a spinning temperature of 285-295° C., a cooling temperature of 19-22° C., an interlacing pressure of 0.20-0.30 MPa, a godet roller 1 speed of 2300-2700 m/min, a godet roller 1 temperature of 80-90° C., a godet roller 2 speed of 3800-4200 m/min, a godet roller 2 temperature of 115-130° C., and a winding speed of 3730-4120 m/min.

Description

DETAILED DESCRIPTION OF THE EMBODIMENTS

(1) Based on above mentioned method, the following embodiments are carried out for further demonstration in the present invention. It is to be understood that these embodiments are only intended to illustrate the invention and are not intended to limit the scope of the invention. In addition, it should be understood that after reading the contents described in the present invention, those technical personnel in this field can make various changes or modifications to the invention, and these equivalent forms also fall within the scope of the claims attached to the application.

(2) ##STR00003##

Example 1

(3) A method for preparing the degradable polyester fiber, comprising the steps:

(1) Preparation of Modified Polyester

(1.1) Synthesizing 2,5,6,6-tetramethyl-2,5-heptanediol

(4) (a) mixing KOH, 3-methyl-3-hydroxybutyne, 3,3-dimethyl-2-butanone and isopropyl ether in the molar ratio of 1:1:1.2:2.0, then carrying out the reaction in an ice bath for 2 hr, finally obtaining octynlydiol through a series of processes of cooling crystallization, centrifugation, washing, refining and drying;

(5) (b) mixing octynyldiol, alcohol and Pd catalyst in the weight ratio of 2:10:0.01, then carrying out the reaction accompanied with a continuous hydrogen input at 40° C. for 50 min, finally obtaining 2,5,6,6-tetramethyl-2,5-heptanediol through a series of processes of separation and purification; wherein obtained target compound possessing a molecular structure just as shown in Formula (I);

(1.2) Doping Modification of ZrO.SUB.2

(6) (a) evenly mixing the 1.5 wt % of Mg(NO.sub.3).sub.2 aqueous solution and the 22 wt % of ZrO.sub.2 nitric acid solution in a molar ratio 6:100 of Mg.sup.2+ and Zr.sup.4+;

(7) (b) depositing the mixed solution by dripping in 2 mol/L of ammonia water till pH=9, then washing and drying (at 108° C. for 2.5 hr) the precipitate;

(8) (c) after the treatments including a heating at 400° C. for 2.5 hr, a heating at 700° C. for 1.5 hr and a cooling in air, finally grinding the precipitate to obtain the doped ZrO.sub.2 powder with an average particle size of 0.4 micron;

(1.3) Esterification

(9) concocting terephthalic acid, ethylene glycol, 2,5,6,6-tetramethyl-2,5-heptanediol and 2,2-difluoro-1,3-malonic acid into a slurry, then adding in the doped ZrO.sub.2, antimony trioxide, titanium dioxide and triphenyl phosphate and carrying out the esterification in a nitrogen atmosphere with a pressure of 0.3 MPa at 250° C., finally ending the reaction when the water distillation reaching 90% of the theoretical value, wherein the molar ration of terephthalic acid and ethylene glycol is 1:1.5, and being relative to the amount of terephthalic acid, the total addition of 2,5,6,6-tetramethyl-2,5-heptanediol and 2,2-difluoro-1,3-malonic acid (in a molar ratio of 1:1) is 6 mol %, whereas the addition of the doped ZrO.sub.2, antimony trioxide, titanium dioxide and triphenyl phosphate are 0.25 wt %, 0.05 wt %, 2.0 wt % and 0.01 wt %, respectively;

(1.4) Polycondensation

(10) for the esterification products, smoothly reducing the pressure to 499 Pa (absolute value) within 30 min and carrying out reaction at 250° C. for 30 min, successively, further reducing the pressure to 99 Pa (absolute value) and continuing the reaction at 270° C. for 50 min, finally obtaining the modified polyester with a molecular weight of 25000 Da and a molecular weight distribution index of 1.8;

(2) Spinning of Degradable Polyester FDY

(11) through a FDY technological way including stages of metering, spinneret extruding (at 290° C.), cooling (at 20° C.), oiling, stretching as well as heat setting (carried on with the parameters of interlacing pressure 0.25 MPa, godet roller 1 speed 2500 m/min, godet roller 1 temperature 85° C., godet roller 2 speed 4000 m/min, godet roller 2 temperature 120° C.), and winding (4000 m/min), converting the modified polyester into fully dull polyester draw yarns.

(12) Finally obtained degradable polyester fiber has the following performance indices of monofilament fineness 1.5 dtex, breaking strength 3.0 cN/dtex, elongation at break 28.0%, interlacing degree 11/m, linear density deviation rate 1.0%, breaking strength CV value 4.8%, elongation at break CV value 8.7%, boiling water shrinkage rate 7.0%, as well as an intrinsic viscosity drop of 28% after stored at 25° C. and R.H. 65% for 60 months.

(13) Comparison 1

(14) A method for preparing the degradable polyester fiber involved steps basically the same as those in Example 1, except for no addition of 2,5,6,6-tetramethyl-2,5-heptanediol, 2,2-difluoro-1,3-malonic acid and the doped ZrO.sub.2 in step (1.3), from which the finally obtained polyester fiber has the following performance indices of monofilament fineness 1.5 dtex, breaking strength 3.1 cN/dtex, elongation at break 27%, interlacing degree 11/m, linear density deviation rate 1.0%, breaking strength CV value 5.0%, elongation at break CV value 8.7%, boiling water shrinkage rate 7.0%, as well as an intrinsic viscosity drop of 4% after stored at 25° C. and R.H. 65% for 60 months. From the results of Comparison 1 and Example 1, it can be concluded the modification could significantly improve the degradation performance of polyester without the loss in mechanical properties.

(15) Comparison 2

(16) A method for preparing the degradable polyester fiber involved steps basically the same as those in Example 1, except for adopting 3,3-difluoroglutaric acid instead of 2,2-difluoro-1,3-malonic acid in step (1), from which the finally obtained polyester fiber has an intrinsic viscosity drop of 14.8% after stored at 25° C. and R.H. 65% for 60 months. From the results of Comparison 1 and Example, it can be concluded that compared with α-C bonded fluorine atom, β-C bonded fluorine atom in the modified polyester can only make rather weak effect upon the natural degradation of the obtained polyester fiber, because its electron-withdrawing effect just pass to the neighbor atoms of β-C so as to give little influence on the nucleophilic addition reaction of ester carbonyl when attacked by OH.sup.−, and the α-C bonded fluorine atom contained dicarboxylic acid is more effective in improving the natural degradation performance of polyester together with the doped ZrO.sub.2 powder.

Example 2

(17) A method for preparing the degradable polyester fiber, comprising the steps:

(1) Preparation of Modified Polyester

(1.1) Synthesizing 2,5,6,6-tetramethyl-2,5-heptanediol

(18) (a) mixing KOH, 3-methyl-3-hydroxybutyne, 3,3-dimethyl-2-butanone and isopropyl ether in the molar ratio of 1.1:1:1.2:2.3, then carrying out the reaction in an ice bath for 2 hr, finally obtaining octynlydiol through a series of processes of cooling crystallization, centrifugation, washing, refining and drying;

(19) (b) mixing octynyldiol, alcohol and Pd catalyst in the weight ratio of 2:10:0.01, then carrying out the reaction accompanied with a continuous hydrogen input at 45° C. for 50 min, finally obtaining 2,5,6,6-tetramethyl-2,5-heptanediol through a series of processes of separation and purification; wherein obtained target compound possessing a molecular structure just as shown in Formula (I);

(1.2) Doping Modification of ZrO.SUB.2

(20) (a) evenly mixing the 1 wt % of LiNO.sub.3 aqueous solution and the 20 wt % of ZrO.sub.2 nitric acid solution in a molar ratio 5:100 of Li.sup.+ and Zr.sup.4+;

(21) (b) depositing the mixed solution by dripping in 2 mol/L of ammonia water till pH=10, then washing and drying (at 105° C. for 3 hr) the precipitate;

(22) (c) after the treatments including a heating at 400° C. for 2 hr, a heating at 700° C. for 1 hr and a cooling in air, finally grinding the precipitate to obtain the doped ZrO.sub.2 powder with an average particle size of 0.4 micron;

(1.3) Esterification

(23) concocting terephthalic acid, ethylene glycol, 2,5,6,6-tetramethyl-2,5-heptanediol and 2,2-difluoro-1,4-succinic acid into a slurry, then adding in the doped ZrO.sub.2, antimony glycol, titanium dioxide and trimethyl phosphate and carrying out the esterification in a nitrogen atmosphere with a pressure of normal value at 260° C., finally ending the reaction when the water distillation reaching 95% of the theoretical value, wherein the molar ration of terephthalic acid and ethylene glycol is 1:1.2, and being relative to the amount of terephthalic acid, the total addition of 2,5,6,6-tetramethyl-2,5-heptanediol and 2,2-difluoro-1,4-succinic acid (in a molar ratio of 2:2) is 4 mol %, whereas the addition of the doped ZrO.sub.2, antimony trioxide, titanium dioxide and trimethyl phosphate are 0.23 wt %, 0.05 wt %, 2.2 wt % and 0.05 wt %, respectively;

(1.4) Polycondensation

(24) for the esterification products, smoothly reducing the pressure to 450 Pa (absolute value) within 50 min and carrying out reaction at 260° C. for 50 min, successively, further reducing the pressure to 90 Pa (absolute value) and continuing the reaction at 282° C. for 90 min, finally obtaining the modified polyester with a molecular weight of 30000 Da and a molecular weight distribution index of 2.2;

(2) Spinning of Degradable Polyester FDY

(25) through a FDY technological way including stages of metering, spinneret extruding (at 290° C.), cooling (at 20° C.), oiling, stretching as well as heat setting (carried on with the parameters of interlacing pressure 0.25 MPa, godet roller 1 speed 2500 m/min, godet roller 1 temperature 85° C., godet roller 2 speed 4000 m/min, godet roller 2 temperature 120° C.), and winding (4000 m/min), converting the modified polyester into fully dull polyester draw yarns.

(26) Finally obtained degradable polyester fiber has the following performance indices of monofilament fineness 2.0 dtex, breaking strength 3.3 cN/dtex, elongation at break 36%, interlacing degree 15/m, linear density deviation rate 0.8%, breaking strength CV value 4.2%, elongation at break CV value 8.1%, boiling water shrinkage rate 6.0%, as well as an intrinsic viscosity drop of 23% after stored at 25° C. and R.H. 65% for 60 months.

Example 3

(27) A method for preparing the degradable polyester fiber, comprising the steps:

(1) Preparation of Modified Polyester

(1.1) Synthesizing 2,5,6,6-tetramethyl-2,5-heptanediol

(28) (a) mixing KOH, 3-methyl-3-hydroxybutyne, 3,3-dimethyl-2-butanone and isopropyl ether in the molar ratio of 1.2:1:1.25:2.0, then carrying out the reaction in an ice bath for 3 hr, finally obtaining octynlydiol through a series of processes of cooling crystallization, centrifugation, washing, refining and drying;

(29) (b) mixing octynyldiol, alcohol and Pd catalyst in the weight ratio of 3:10:0.03, then carrying out the reaction accompanied with a continuous hydrogen input at 40° C. for 50 min, finally obtaining 2,5,6,6-tetramethyl-2,5-heptanediol through a series of processes of separation and purification; wherein obtained target compound possessing a molecular structure just as shown in Formula (I);

(1.2) Doping Modification of ZrO.SUB.2

(30) (a) evenly mixing the 2 wt % of Zn(NO.sub.3).sub.2 aqueous solution and the 25 wt % of ZrO.sub.2 nitric acid solution in a molar ratio 8:100 of Zn.sup.2+ and Zr.sup.4+;

(31) (b) depositing the mixed solution by dripping in 2 mol/L of ammonia water till pH=10, then washing and drying (at 110° C. for 2 hr) the precipitate;

(32) (c) after the treatments including a heating at 400° C. for 3 hr, a heating at 700° C. for 2 hr and a cooling in air, finally grinding the precipitate to obtain the doped ZrO.sub.2 powder with an average particle size of 0.4 micron;

(1.3) Esterification

(33) concocting terephthalic acid, ethylene glycol, 2,5,6,6-tetramethyl-2,5-heptanediol and 2,2-difluoro-1,5-glutaric acid into a slurry, then adding in the doped ZrO.sub.2, antimony acetate, titanium dioxide and trimethyl phosphite and carrying out the esterification in a nitrogen atmosphere with a pressure of 0.2 MPa at 255° C., finally ending the reaction when the water distillation reaching 95% of the theoretical value, wherein the molar ration of terephthalic acid and ethylene glycol is 1:1.5, and being relative to the amount of terephthalic acid, the total addition of 2,5,6,6-tetramethyl-2,5-heptanediol and 2,2-difluoro-1,5-glutaric acid (in a molar ratio of 1:2) is 4.4 mol %, whereas the addition of the doped ZrO.sub.2, antimony acetate, titanium dioxide and trimethyl phosphite are 0.23 wt %, 0.05 wt %, 2.3 wt % and 0.01 wt %, respectively;

(1.4) Polycondensation

(34) for the esterification products, smoothly reducing the pressure to 480 Pa (absolute value) within 40 min and carrying out reaction at 255° C. for 40 min, successively, further reducing the pressure to 95 Pa (absolute value) and continuing the reaction at 272° C. for 70 min, finally obtaining the modified polyester with a molecular weight of 27000 Da and a molecular weight distribution index of 2.0;

(2) Spinning of Degradable Polyester FDY

(35) through a FDY technological way including stages of metering, spinneret extruding (at 290° C.), cooling (at 20° C.), oiling, stretching as well as heat setting (carried on with the parameters of interlacing pressure 0.25 MPa, godet roller 1 speed 2500 m/min, godet roller 1 temperature 85° C., godet roller 2 speed 4000 m/min, godet roller 2 temperature 120° C.), and winding (4000 m/min), converting the modified polyester into fully dull polyester draw yarns.

(36) Finally obtained degradable polyester fiber has the following performance indices of monofilament fineness 1.0 dtex, breaking strength 3.3 cN/dtex, elongation at break 35%, interlacing degree 14/m, linear density deviation rate 0.9%, breaking strength CV value 4.3%, elongation at break CV value 8.1%, boiling water shrinkage rate 6.2%, as well as an intrinsic viscosity drop of 24% after stored at 25° C. and R.H. 65% for 60 months.

Example 4

(37) A method for preparing the degradable polyester fiber, comprising the steps:

(1) Preparation of Modified Polyester

(1.1) Synthesizing 2,5,6,6-tetramethyl-2,5-heptanediol

(38) (a) mixing KOH, 3-methyl-3-hydroxybutyne, 3,3-dimethyl-2-butanone and isopropyl ether in the molar ratio of 1.2:1:1.3:2.5, then carrying out the reaction in an ice bath for 3 hr, finally obtaining octynlydiol through a series of processes of cooling crystallization, centrifugation, washing, refining and drying;

(39) (b) mixing octynyldiol, alcohol and Pd catalyst in the weight ratio of 2.5:10:0.02, then carrying out the reaction accompanied with a continuous hydrogen input at 45° C. for 60 min, finally obtaining 2,5,6,6-tetramethyl-2,5-heptanediol through a series of processes of separation and purification; wherein obtained target compound possessing a molecular structure just as shown in Formula (I);

(1.2) Doping Modification of ZrO.SUB.2

(40) (a) evenly mixing the 1.2 wt % of Mg(NO.sub.3).sub.2 aqueous solution and the 22 wt % of ZrO.sub.2 nitric acid solution in a molar ratio 6:100 of Mg.sup.2+ and Zr.sup.4+;

(41) (b) depositing the mixed solution by dripping in 2 mol/L of ammonia water till pH=9, then washing and drying (at 106° C. for 2.5 hr) the precipitate;

(42) (c) after the treatments including a heating at 400° C. for 2.5 hr, a heating at 700° C. for 1.5 hr and a cooling in air, finally grinding the precipitate to obtain the doped ZrO.sub.2 powder with an average particle size of 0.4 micron;

(1.3) Esterification

(43) concocting terephthalic acid, ethylene glycol, 2,5,6,6-tetramethyl-2,5-heptanediol and 2,2-difluoro-1,5-glutaric acid into a slurry, then adding in the doped ZrO.sub.2, antimony glycol, titanium dioxide and triphenyl phosphate and carrying out the esterification in a nitrogen atmosphere with a pressure of 0.25 MPa at 250° C., finally ending the reaction when the water distillation reaching 95% of the theoretical value, wherein the molar ration of terephthalic acid and ethylene glycol is 1:1.4, and being relative to the amount of terephthalic acid, the total addition of 2,5,6,6-tetramethyl-2,5-heptanediol and 2,2-difluoro-1,5-glutaric acid (in a molar ratio of 1.5:1) is 4.6 mol %, whereas the addition of the doped ZrO.sub.2, antimony glycol, titanium dioxide and triphenyl phosphate are 0.24 wt %, 0.07 wt %, 3.0 wt % and 0.01 wt %, respectively;

(1.4) Polycondensation

(44) for the esterification products, smoothly reducing the pressure to 480 Pa (absolute value) within 35 min and carrying out reaction at 258° C. for 45 min, successively, further reducing the pressure to 96 Pa (absolute value) and continuing the reaction at 270° C. for 55 min, finally obtaining the modified polyester with a molecular weight of 26000 Da and a molecular weight distribution index of 1.9;

(2) Spinning of Degradable Polyester FDY

(45) through a FDY technological way including stages of metering, spinneret extruding (at 290° C.), cooling (at 20° C.), oiling, stretching as well as heat setting (carried on with the parameters of interlacing pressure 0.25 MPa, godet roller 1 speed 2500 m/min, godet roller 1 temperature 85° C., godet roller 2 speed 4000 m/min, godet roller 2 temperature 120° C.), and winding (4000 m/min), converting the modified polyester into fully dull polyester draw yarns.

(46) Finally obtained degradable polyester fiber has the following performance indices of monofilament fineness 1.5 dtex, breaking strength 3.2 cN/dtex, elongation at break 34%, interlacing degree 14/m, linear density deviation rate 0.8%, breaking strength CV value 4.5%, elongation at break CV value 8.2%, boiling water shrinkage rate 6.3%, as well as an intrinsic viscosity drop of 25% after stored at 25° C. and R.H. 65% for 60 months.

Example 5

(47) A method for preparing the degradable polyester fiber, comprising the steps:

(1) Preparation of Modified Polyester

(1.1) Synthesizing 2,5,6,6-tetramethyl-2,5-heptanediol

(48) (a) mixing KOH, 3-methyl-3-hydroxybutyne, 3,3-dimethyl-2-butanone and isopropyl ether in the molar ratio of 1:1:1.3:3.0, then carrying out the reaction in an ice bath for 4 hr, finally obtaining octynlydiol through a series of processes of cooling crystallization, centrifugation, washing, refining and drying;

(49) (b) mixing octynyldiol, alcohol and Pd catalyst in the weight ratio of 2.5:10:0.02, then carrying out the reaction accompanied with a continuous hydrogen input at 50° C. for 55 min, finally obtaining 2,5,6,6-tetramethyl-2,5-heptanediol through a series of processes of separation and purification; wherein obtained target compound possessing a molecular structure just as shown in Formula (I);

(1.2) Doping Modification of ZrO.SUB.2

(50) (a) evenly mixing the 1.6 wt % of LiNO.sub.3 aqueous solution and the 24 wt % of ZrO.sub.2 nitric acid solution in a molar ratio 7:100 of Li.sup.+ and Zr.sup.4+;

(51) (b) depositing the mixed solution by dripping in 2 mol/L of ammonia water till pH=9-10, then washing and drying (at 110° C. for 2 hr) the precipitate;

(52) (c) after the treatments including a heating at 400° C. for 3 hr, a heating at 700° C. for 2 hr and a cooling in air, finally grinding the precipitate to obtain the doped ZrO.sub.2 powder with an average particle size of 0.45 micron;

(1.3) Esterification

(53) concocting terephthalic acid, ethylene glycol, 2,5,6,6-tetramethyl-2,5-heptanediol and 2,2,3,3-tetrafluoro-1,4-succinic acid into a slurry, then adding in the doped ZrO.sub.2, antimony acetate, titanium dioxide and triphenyl phosphate and carrying out the esterification in a nitrogen atmosphere with a pressure of 0.15 MPa at 260° C., finally ending the reaction when the water distillation reaching 95% of the theoretical value, wherein the molar ration of terephthalic acid and ethylene glycol is 1:1.5, and being relative to the amount of terephthalic acid, the total addition of 2,5,6,6-tetramethyl-2,5-heptanediol and 2,2,3,3-tetrafluoro-1,4-succinic acid (in a molar ratio of 1:1.5) is 4.9 mol %, whereas the addition of the doped ZrO.sub.2, antimony acetate, titanium dioxide and triphenyl phosphate are 0.24 wt %, 0.05 wt %, 2.0 wt % and 0.01 wt %, respectively;

(1.4) Polycondensation

(54) for the esterification products, smoothly reducing the pressure to 480 Pa (absolute value) within 50 min and carrying out reaction at 255° C. for 50 min, successively, further reducing the pressure to 95 Pa (absolute value) and continuing the reaction at 282° C. for 80 min, finally obtaining the modified polyester with a molecular weight of 29000 Da and a molecular weight distribution index of 2.1;

(2) Spinning of Degradable Polyester FDY

(55) through a FDY technological way including stages of metering, spinneret extruding (at 295° C.), cooling (at 19° C.), oiling, stretching as well as heat setting (carried on with the parameters of interlacing pressure 0.20 MPa, godet roller 1 speed 2300 m/min, godet roller 1 temperature 80° C., godet roller 2 speed 3800 m/min, godet roller 2 temperature 115° C.), and winding (3730 m/min), converting the modified polyester into fully dull polyester draw yarns.

(56) Finally obtained degradable polyester fiber has the following performance indices of monofilament fineness 1.5 dtex, breaking strength 3.2 cN/dtex, elongation at break 32%, interlacing degree 12/m, linear density deviation rate 0.9%, breaking strength CV value 4.6%, elongation at break CV value 8.5%, boiling water shrinkage rate 6.5%, as well as an intrinsic viscosity drop of 26% after stored at 25° C. and R.H. 65% for 60 months.

Example 6

(57) A method for preparing the degradable polyester fiber, comprising the steps:

(1) Preparation of Modified Polyester

(1.1) Synthesizing 2,5,6,6-tetramethyl-2,5-heptanediol

(58) (a) mixing KOH, 3-methyl-3-hydroxybutyne, 3,3-dimethyl-2-butanone and isopropyl ether in the molar ratio of 1.1:1:1.2:3.0, then carrying out the reaction in an ice bath for 4 hr, finally obtaining octynlydiol through a series of processes of cooling crystallization, centrifugation, washing, refining and drying;

(59) (b) mixing octynyldiol, alcohol and Pd catalyst in the weight ratio of 3:10:0.03, then carrying out the reaction accompanied with a continuous hydrogen input at 50° C. for 60 smin, finally obtaining 2,5,6,6-tetramethyl-2,5-heptanediol through a series of processes of separation and purification; wherein obtained target compound possessing a molecular structure just as shown in Formula (I);

(1.2) Doping Modification of ZrO.SUB.2

(60) (a) evenly mixing the 2 wt % of Mg(NO.sub.3).sub.2 and Zn(NO.sub.3).sub.2 aqueous solution in a weight ratio of 1:1 to obtain a mixture solution of metal ion M.sup.x+, and then blending the mixture with the 20 wt % of ZrO.sub.2 nitric acid solution in a molar ratio 8:100 of M.sup.x+ and Zr.sup.4+;

(61) (b) depositing the mixed solution by dripping in 2 mol/L of ammonia water till pH=10, then washing and drying (at 110° C. for 2 hr) the precipitate;

(62) (c) after the treatments including a heating at 400° C. for 2 hr, a heating at 700° C. for 1 hr and a cooling in air, finally grinding the precipitate to obtain the doped ZrO.sub.2 powder with an average particle size of 0.4 micron;

(1.3) Esterification

(63) concocting terephthalic acid, ethylene glycol, 2,5,6,6-tetramethyl-2,5-heptanediol and 2,2,3,3-tetrafluoro-1,4-succinic acid into a slurry, then adding in the doped ZrO.sub.2, antimony acetate, titanium dioxide and triphenyl phosphate and carrying out the esterification in a nitrogen atmosphere with a pressure of 0.3 MPa at 250° C., finally ending the reaction when the water distillation reaching 95% of the theoretical value, wherein the molar ration of terephthalic acid and ethylene glycol is 1:1.6, and being relative to the amount of terephthalic acid, the total addition of 2,5,6,6-tetramethyl-2,5-heptanediol and 2,2,3,3-tetrafluoro-1,4-succinic acid (in a molar ratio of 1.2:1) is 5.2 mol %, whereas the addition of the doped ZrO.sub.2, antimony acetate, titanium dioxide and triphenyl phosphate are 0.25 wt %, 0.05 wt %, 2.8 wt % and 0.01 wt %, respectively;

(1.4) Polycondensation

(64) for the esterification products, smoothly reducing the pressure to 450 Pa (absolute value) within 30 min and carrying out reaction at 260° C. for 30 min, successively, further reducing the pressure to 92 Pa (absolute value) and continuing the reaction at 272° C. for 85 min, finally obtaining the modified polyester with a molecular weight of 28000 Da and a molecular weight distribution index of 1.8;

(2) Spinning of Degradable Polyester FDY

(65) through a FDY technological way including stages of metering, spinneret extruding (at 295° C.), cooling (at 19° C.), oiling, stretching as well as heat setting (carried on with the parameters of interlacing pressure 0.20 MPa, godet roller 1 speed 2300 m/min, godet roller 1 temperature 80° C., godet roller 2 speed 3800 m/min, godet roller 2 temperature 115° C.), and winding (3730 m/min), converting the modified polyester into fully dull polyester draw yarns.

(66) Finally obtained degradable polyester fiber has the following performance indices of monofilament fineness 1.5 dtex, breaking strength 3.2 cN/dtex, elongation at break 30%, interlacing degree 11/m, linear density deviation rate 1.0%, breaking strength CV value 4.8%, elongation at break CV value 8.6%, boiling water shrinkage rate 6.7%, as well as an intrinsic viscosity drop of 26% after stored at 25° C. and R.H. 65% for 60 months.

Example 7

(67) A method for preparing the degradable polyester fiber, comprising the steps:

(1) Preparation of Modified Polyester

(1.1) Synthesizing 2,5,6,6-tetramethyl-2,5-heptanediol

(68) (a) mixing KOH, 3-methyl-3-hydroxybutyne, 3,3-dimethyl-2-butanone and isopropyl ether in the molar ratio of 1.2:1:1.2:3.0, then carrying out the reaction in an ice bath for 3 hr, finally obtaining octynlydiol through a series of processes of cooling crystallization, centrifugation, washing, refining and drying;

(69) (b) mixing octynyldiol, alcohol and Pd catalyst in the weight ratio of 3:10:0.02, then carrying out the reaction accompanied with a continuous hydrogen input at 42° C. for 55 min, finally obtaining 2,5,6,6-tetramethyl-2,5-heptanediol through a series of processes of separation and purification; wherein obtained target compound possessing a molecular structure just as shown in Formula (I);

(1.2) Doping Modification of ZrO.SUB.2

(70) (a) evenly mixing the 1 wt % of Mg(NO.sub.3).sub.2 and LiNO.sub.3 aqueous solution in a weight ratio of 1:1 to obtain a mixture solution of metal ion M.sup.x+, and then blending the mixture with the 24 wt % of ZrO.sub.2 nitric acid solution in a molar ratio 6:100 of M.sup.x+ and Zr.sup.4+;

(71) (b) depositing the mixed solution by dripping in 2 mol/L of ammonia water till pH=10, then washing and drying (at 110° C. for 3 hr) the precipitate;

(72) (c) after the treatments including a heating at 400° C. for 2 hr, a heating at 700° C. for 2 hr and a cooling in air, finally grinding the precipitate to obtain the doped ZrO.sub.2 powder with an average particle size of 0.45 micron;

(1.3) Esterification

(73) concocting terephthalic acid, ethylene glycol, 2,5,6,6-tetramethyl-2,5-heptanediol and 2,2-difluoro-1,3-malonic acid into a slurry, then adding in the doped ZrO.sub.2, antimony trioxide, titanium dioxide and trimethyl phosphite and carrying out the esterification in a nitrogen atmosphere with a pressure of 0.2 MPa at 255° C., finally ending the reaction when the water distillation reaching 95% of the theoretical value, wherein the molar ration of terephthalic acid and ethylene glycol is 1:1.6, and being relative to the amount of terephthalic acid, the total addition of 2,5,6,6-tetramethyl-2,5-heptanediol and 2,2-difluoro-1,3-malonic acid (in a molar ratio of 2:1.5) is 5.4 mol %, whereas the addition of the doped ZrO.sub.2, antimony trioxide, titanium dioxide and trimethyl phosphite are 0.25 wt %, 0.04 wt %, 3.0 wt % and 0.05 wt %, respectively;

(1.4) Polycondensation

(74) for the esterification products, smoothly reducing the pressure to 490 Pa (absolute value) within 50 min and carrying out reaction at 255° C. for 50 min, successively, further reducing the pressure to 95 Pa (absolute value) and continuing the reaction at 275° C. for 55 min, finally obtaining the modified polyester with a molecular weight of 25000 Da and a molecular weight distribution index of 2.2;

(2) Spinning of Degradable Polyester FDY

(75) through a FDY technological way including stages of metering, spinneret extruding (at 285° C.), cooling (at 22° C.), oiling, stretching as well as heat setting (carried on with the parameters of interlacing pressure 0.30 MPa, godet roller 1 speed 2700 m/min, godet roller 1 temperature 90° C., godet roller 2 speed 4200 m/min, godet roller 2 temperature 130° C.), and winding (4120 m/min), converting the modified polyester into fully dull polyester draw yarns.

(76) Finally obtained degradable polyester fiber has the following performance indices of monofilament fineness 1.0 dtex, breaking strength 3.1 cN/dtex, elongation at break 30%, interlacing degree 15/m, linear density deviation rate 1.0%, breaking strength CV value 4.7%, elongation at break CV value 8.8%, boiling water shrinkage rate 6.8%, as well as an intrinsic viscosity drop of 27% after stored at 25° C. and R.H. 65% for 60 months.

Example 8

(77) A method for preparing the degradable polyester fiber, comprising the steps:

(1) Preparation of Modified Polyester

(1.1) Synthesizing 2,5,6,6-tetramethyl-2,5-heptanediol

(78) (a) mixing KOH, 3-methyl-3-hydroxybutyne, 3,3-dimethyl-2-butanone and isopropyl ether in the molar ratio of 1.2:1:1.2:3.0, then carrying out the reaction in an ice bath for 3 hr, finally obtaining octynlydiol through a series of processes of cooling crystallization, centrifugation, washing, refining and drying;

(79) (b) mixing octynyldiol, alcohol and Pd catalyst in the weight ratio of 3:10:0.02, then carrying out the reaction accompanied with a continuous hydrogen input at 42° C. for 55 min, finally obtaining 2,5,6,6-tetramethyl-2,5-heptanediol through a series of processes of separation and purification; wherein obtained target compound possessing a molecular structure just as shown in Formula (I);

(1.2) Doping Modification of ZrO.SUB.2

(80) (a) evenly mixing the 1 wt % of Mg(NO.sub.3).sub.2 and LiNO.sub.3 aqueous solution in a weight ratio of 1:1 to obtain a mixture solution of metal ion M.sup.x+, and then blending the mixture with the 24 wt % of ZrO.sub.2 nitric acid solution in a molar ratio 6:100 of M.sup.x+ and Zr.sup.4+;

(81) (b) depositing the mixed solution by dripping in 2 mol/L of ammonia water till pH=10, then washing and drying (at 110° C. for 3 hr) the precipitate;

(82) (c) after the treatments including a heating at 400° C. for 2 hr, a heating at 700° C. for 2 hr and a cooling in air, finally grinding the precipitate to obtain the doped ZrO.sub.2 powder with an average particle size of 0.45 micron;

(1.3) Esterification

(83) concocting terephthalic acid, ethylene glycol, 2,5,6,6-tetramethyl-2,5-heptanediol and 2,2-difluoro-1,3-malonic acid into a slurry, then adding in the doped ZrO.sub.2, antimony glycol, titanium dioxide and triphenyl phosphate and carrying out the esterification in a nitrogen atmosphere with a pressure of 0.3 MPa at 255° C., finally ending the reaction when the water distillation reaching 95% of the theoretical value, wherein the molar ration of terephthalic acid and ethylene glycol is 1:2.0, and being relative to the amount of terephthalic acid, the total addition of 2,5,6,6-tetramethyl-2,5-heptanediol and 2,2-difluoro-1,3-malonic acid (in a molar ratio of 2:1) is 5.8 mol %, whereas the addition of the doped ZrO.sub.2, antimony glycol, titanium dioxide and triphenyl phosphate are 0.25 wt %, 0.04 wt %, 2.0 wt % and 0.03 wt %, respectively;

(1.4) Polycondensation

(84) for the esterification products, smoothly reducing the pressure to 480 Pa (absolute value) within 50 min and carrying out reaction at 260° C. for 40 min, successively, further reducing the pressure to 95 Pa (absolute value) and continuing the reaction at 272° C. for 90 min, finally obtaining the modified polyester with a molecular weight of 29000 Da and a molecular weight distribution index of 2.1;

(2) Spinning of Degradable Polyester FDY

(85) through a FDY technological way including stages of metering, spinneret extruding (at 285° C.), cooling (at 22° C.), oiling, stretching as well as heat setting (carried on with the parameters of interlacing pressure 0.30 MPa, godet roller 1 speed 2700 m/min, godet roller 1 temperature 90° C., godet roller 2 speed 4200 m/min, godet roller 2 temperature 130° C.), and winding (4120 m/min), converting the modified polyester into fully dull polyester draw yarns.

(86) Finally obtained degradable polyester fiber has the following performance indices of monofilament fineness 1.0 dtex, breaking strength 3.0 cN/dtex, elongation at break 29%, interlacing degree 11/m, linear density deviation rate 1.0%, breaking strength CV value 5.0%, elongation at break CV value 8.8%, boiling water shrinkage rate 7.0%, as well as an intrinsic viscosity drop of 28% after stored at 25° C. and R.H. 65% for 60 months.