CN109750374B

CN109750374B - Semi-dull polyester low stretch yarn and preparation method thereof

Info

Publication number: CN109750374B
Application number: CN201811614007.7A
Authority: CN
Inventors: 汤方明; 周文龙; 张元华
Original assignee: Jiangsu Hengli Chemical Fiber Co Ltd
Current assignee: Jiangsu Hengli Chemical Fiber Co Ltd
Priority date: 2018-12-27
Filing date: 2018-12-27
Publication date: 2020-07-07
Anticipated expiration: 2038-12-27
Also published as: CN109750374A

Abstract

The invention relates to a semi-dull terylene low stretch yarn and a preparation method thereof, wherein the preparation method comprises the following steps: preparing modified polyester POY yarns from the modified polyester melt according to a POY process, and preparing modified polyester DTY yarns from the modified polyester POY yarns according to a DTY process to obtain semi-dull polyester low stretch yarns; the molecular chain of the modified polyester comprises a terephthalic acid chain segment, an ethylene glycol chain segment and a fluorine-containing diacid chain segment; the modified polyester is dispersed with delustering agent and doped modified ZrO₂Powder and doping modified Sb₂O₃And (3) powder. After the prepared product is placed for 60 months under the conditions that the temperature is 25 ℃ and the relative humidity is 65%, the intrinsic viscosity of the product is reduced by 15-18%. The preparation method has the advantages of simple process and low cost, reduces the addition of the antimony catalyst, and reduces the emission of antimony; the prepared product has high natural degradation rate and good application prospect.

Description

Semi-dull polyester low stretch yarn and preparation method thereof

Technical Field

The invention belongs to the technical field of modified polyester fibers, and relates to a semi-dull terylene low stretch yarn and a preparation method thereof.

Background

The polyester fiber is the most industrialized but the development speed is the fastest among three synthetic fibers (polyester fiber, chinlon fiber and polypropylene fiber). At present, the global demand of terylene still increases at a speed of 6 to 7 percent per year, and the demand of terylene increases so fast, mainly has the following characteristics: 1) the terylene has excellent performance, high modulus and good heat resistance, and is a relatively ideal textile fiber material; 2) the mechanical property plasticity of terylene is large, and cotton type or wool type short fiber, filament or industrial products can be produced by different processing methods; 3) due to the development of the petrochemical industry, raw materials required by the polyester production can be more economically and conveniently obtained, and the threshold of the industry for the production enterprises to enter is greatly reduced; 4) the price is low, and the price of the prior terylene is lower than that of all other synthetic fibers except the polypropylene fiber.

With the social progress and the improvement of living standard, people have higher and higher requirements on fiber, and the requirements are developed from initial firm wear resistance to current comfort and functionality. Differentiation and functionalization of polyester fibers are the inevitable requirements for development.

Because the conventional terylene has regular shape, smooth surface and certain transparency, the terylene can be irradiated by lightThe intensity of the reflected light is very high, the phenomena of reflection and flicker are obvious, and the visual comfort of the fiber is not high. A small amount of substances with different refractive indexes are added into the fiber, so that light rays are subjected to diffuse reflection in different directions, the glossiness of the fiber is reduced, the visual comfort degree of the fiber is improved, and the extinction treatment of the fiber product is realized. Titanium dioxide is commonly called titanium white due to its high refractive index (TiO)₂Refractive index of 2.60 and air of 1.00) is added to the polyester, and extinction can be achieved by utilizing the refractive index difference between the polyester and the polyester, so that the polyester extinction additive is ideal.

In addition, stretch is an important property of fibers, and stretch yarns are classified into high stretch yarns and low stretch yarns. The polyester low stretch yarn is a fiber which is prepared by using polyester chips (PET) as a raw material, spinning polyester pre-oriented yarn (POY) at a high speed, and then performing drafting and false twisting processing. The terylene heat insulation material not only has the characteristics of high breaking strength and high elastic modulus, excellent heat setting property, excellent rebound resilience, excellent heat resistance, good light resistance, good corrosion resistance, easy washing, quick drying and the like of common terylene, but also has the characteristics of high bulkiness, good heat insulation property, comfortable hand feeling, soft luster and the like. In addition, the polyester fiber has short processing flow and high processing efficiency, and is a polyester fiber with wide application.

However, with the rapid development of the PET industry, although PET does not directly cause harm to the environment, its waste products after use are huge in number and have strong resistance to atmosphere and microbial agents, and the waste of the produced fibers is not easy to treat, which indirectly causes harm to the environment. At present, the treatment method of PET fiber waste mainly comprises the following steps: burying, burning and recycling. From the environmental point of view, landfill and incineration, although the simplest methods, have many drawbacks and cause some environmental pollution. The chemical degradation recovery is an effective and scientific way for treating the PET wastes, the main methods comprise alcoholysis, ammonolysis and the like, and products of chemical degradation such as alcohol, acid, ester and the like can also be reused as chemical raw materials. However, because the PET has a compact structure and high crystallinity, the natural degradation time is very long (the degradation period of the conventional PET fiber can reach 16-48 years), which greatly limits the application of chemical degradation recovery in the field of PET waste treatment.

Therefore, the development of the semi-dull terylene low stretch yarn electrode capable of efficiently degrading and recycling has practical significance.

Disclosure of Invention

The invention aims to overcome the defect of slow natural degradation rate in the prior art and provides a semi-dull polyester low stretch yarn with high natural degradation rate and a preparation method thereof.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

the preparation method of the semi-dull polyester low stretch yarn comprises the steps of preparing modified polyester POY yarns from a modified polyester melt according to a POY process, and preparing modified polyester DTY yarns from the modified polyester POY yarns according to a DTY process to obtain the semi-dull polyester low stretch yarns;

the preparation method of the modified polyester comprises the following steps: terephthalic acid, ethylene glycol, fluorine-containing dibasic acid, a delustering agent and doping modified ZrO₂Powder and doping modified Sb₂O₃Uniformly mixing the powder, and then carrying out esterification reaction and polycondensation reaction in sequence;

the fluorine-containing dibasic acid is 2, 2-difluoro-1, 3-malonic acid, 2-difluoro-1, 4-succinic acid, 2-difluoro-1, 5-glutaric acid or 2,2,3, 3-tetrafluoro-1, 4-succinic acid;

the content of the matting agent in the modified polyester is 0.20-0.25 wt%;

ZrO₂the doping modification process comprises the following steps: firstly, containing metal ions M^x+With Zr-containing solution⁴⁺Uniformly mixing the solution, then dropwise adding a precipitator until the pH value of the mixed solution is 9-10, and finally calcining the precipitate;

metal ion M^x+Is Mg²⁺、Li⁺And Zn²⁺One or more of (1);

Sb₂O₃the doping modification process comprises the following steps: firstly, the metal ions N are contained^y+With Sb-containing solution³⁺Uniformly mixing the solution, then dropwise adding a precipitator until the pH value of the mixed solution is 9-10, and finally calcining the precipitate;

metal ion N^y+Is Mg²⁺、Ca²⁺、Ba²⁺And Zn²⁺One or more of (1);

the invention realizes the metal oxide (more than one of magnesium oxide, lithium oxide and zinc oxide) and ZrO by the method of solution blending, coprecipitation and calcination₂Doping of, and then to ZrO₂The oxygen reduction catalytic process of the invention has influence, the degradation rate of the polyester is improved, and because the invention selects ZrO with high ionic conductivity₂As oxygen reduction catalyst substrate by doping with metal ions (Mg) in lower valence state²⁺、Li⁺And Zn²⁺) Can obtain stable cubic phase, and to a certain extent, the closer the radius of doped ions is to the radius of the doped ions, the more favorable the formation of oxygen vacancies and the more favorable the conduction of oxygen ions, the doping and Zr are selected in the invention⁴⁺Metal ions (Mg) having the same ionic radius²⁺、Li⁺And Zn²⁺Ion radii of all 0.103nm), which can improve the conduction rate of oxygen ions and further improve the degree of oxygen reduction reaction;

the invention is realized by adding N containing metal ions^y+With Sb-containing solution³⁺The solution is mixed uniformly, precipitated and calcined, so that the doping and blending of metal oxide with certain catalytic activity and antimony trioxide are realized, the metal oxide is more than one of MgO, CaO, BaO and ZnO, and after the metal oxide is doped with the antimony trioxide, the metal oxide enters the lattice site of the antimony by inhibiting the crystallization of the antimony trioxide, the growth of cubic antimony trioxide crystal grains and isomorphous substitution of the antimony, so that the antimony trioxide crystal generates defects, the crystal form generates change, the crystal grain size is reduced, and the specific surface area S of the antimony trioxide catalyst is improved_gMeanwhile, the metal is also enriched on the surface of part of the antimony trioxide crystal, so that the activity r on the unit surface area of the antimony trioxide_sIncrease of specific surface area S_gAnd activity per unit surface area r_sThe larger the catalyst, the higher the catalytic activity of the catalyst, and further the reduction of Sb in the preparation process₂O₃The addition amount of (A) to reduce the cost;

the added fluorine-containing dibasic acid is characterized in that fluorine atoms are on α carbon, when the fluorine-containing dibasic acid is introduced in the hydrolysis process, the electron-withdrawing capability of the fluorine atoms on α carbon is strong, so that the electron cloud density on a C-O bond in polyester is reduced, the stability of tetrahedral negative ions is reduced, the nucleophilic addition reaction is facilitated, and meanwhile, the steric hindrance of the fluorine-containing dibasic acid on α carbon is smaller than that of terephthalic acid, so that the nucleophilic addition reaction is further promoted, and the degradation rate is remarkably improved;

the invention introduces fluorine-containing dibasic acid and doping modified ZrO in a polyester molecular chain₂The powder can also play a synergistic role, the fluorine-containing dibasic acid has stronger electron-withdrawing capability because the fluorine atom is on α carbon, so that the electron cloud density on the C-O bond in the polyester is reduced, the stability of tetrahedral negative ions is reduced, the degradation reaction is favorably carried out, and the doped modified ZrO₂The powder can improve the conduction rate of oxygen ions, accelerate the oxygen reduction reaction and further promote the degradation reaction, thereby further improving the natural degradation rate;

the temperature of a second hot box of the DTY process is 160-180 ℃, the general high stretch yarn which is not heated by the second hot box is high stretch yarn, the general low stretch yarn which is heated by the second hot box is low stretch yarn, and the low stretch yarn is prepared by the method.

As a preferred technical scheme:

the preparation method of the semi-dull terylene low stretch yarn comprises the step of preparing ZrO₂When doping modification is carried out, the metal ions M are contained^x+The concentration of the solution is 1-2 wt%, the solvent is water, and the anion in the solution is NO₃ ^-(ii) a Said Zr containing⁴⁺The solution of (a) is 20-25 wt% ZrO₂The solvent of (1) is nitric acid; the precipitator is ammonia water with the concentration of 2 mol/L; at the beginning of precipitation, metal ion M in the mixture^x+With Zr⁴⁺The molar ratio of (A) to (B) is 5-8: 100; washing and drying the precipitate product before calcining, wherein the drying temperature is 105-110 ℃, and the drying time is 2-3 h; the calcining process comprises the following steps: firstly, heating to 400 ℃, then preserving heat for 2-3 h, then heating to 700 ℃, preserving heat for 1-2 h, and finally cooling in the air; ZrO (ZrO)₂After doping modification, crushing to obtain powder with the average grain diameter of less than 0.5 micron; metal ion M of the invention^x+With Zr⁴⁺The molar ratio of (A) is not limited thereto, and those skilled in the art can adjust the molar ratio according to the actual conditions, but the adjustment range is not too large because ZrO in the catalyst₂Is a main body, metal ion M^x+Is introduced to surround ZrO₂The purpose of this is to increase the oxygen ion conduction rate and further to increase the degree of oxygen reduction reaction, and if the molar ratio is too large, the oxygen ion conduction rate will not be increased, while if it is too small, the oxygen ion conduction rate will not be increased sufficiently.

The preparation method of the semi-dull terylene low stretch yarn is used for treating Sb₂O₃When doping modification is carried out, the metal ion N is contained^y+The concentration of the solution is 0.5-1.0 mol%, the solvent is water, and the anion in the solution is NO₃ ^-(ii) a The Sb-containing compound³⁺The solution of (a) is Sb with the concentration of 5-10 mol%₂O₃The solvent of (1) is oxalic acid; the precipitator is ammonia water with the concentration of 2 mol/L; at the beginning of precipitation, the metal ion N in the mixed solution^y+And Sb³⁺In a molar ratio of 1-3: 100, Sb₂O₃Is the polyester catalyst with highest cost performance at present, and is prepared by permeating metal oxide (namely M)₂O_X) Inhibiting antimony trioxide (Sb)₂O₃) Crystallization of (2) and growth of cubic antimony trioxide grains, with metal ion N^y+Can replace antimony to enter the lattice site of antimony, so that the antimony trioxide crystal generates defects to improve the catalytic activity of antimony trioxide; if the amount of the doped metal oxide is too small (the molar ratio is too low), the influence on the crystal grains of the antimony trioxide is low, and if the amount of the doped metal oxide is too large (the molar ratio is too high), the Sb in the main body of the catalyst is enabled to be too much³⁺The large reduction range is not favorable for improving the catalytic activity of the antimony trioxide; washing and drying the precipitation product before calcining at the temperature of 105-110 ℃ for 2-3 h, wherein the treatment process of the precipitation product before calcining after precipitating comprises but is not limited to the steps of sufficiently removing OH on the surface of the precipitation product as long as the OH on the surface of the precipitation product can be sufficiently removed^-And the moisture therein, the treatment process capable of avoiding the adverse effects of impurities and water molecules on the calcination is suitable for the invention; the calcining process comprises the following steps: firstly, heating to 400 ℃, then preserving heat for 2-3 h, and thenHeating to 900 ℃, preserving heat for 1-2 h, and finally cooling in air; sb₂O₃The calcination process of the invention includes but is not limited to the calcination process of obtaining the powder with the average grain diameter less than 0.5 micron by crushing after doping modification, and other metal oxides (MgO, CaO, BaO and ZnO) and antimony trioxide can be doped to realize the doping of the Sb₂O₃The doping modification calcination process is applicable to the invention.

The preparation method of the semi-dull polyester low stretch yarn comprises the following steps:

(1) performing esterification reaction;

preparing terephthalic acid, ethylene glycol and fluorine-containing dibasic acid into slurry, and adding the doped and modified ZrO₂Powder and doped modified Sb₂O₃Uniformly mixing the powder, the flatting agent and the stabilizing agent, and pressurizing in a nitrogen atmosphere to perform esterification reaction, wherein the pressurizing pressure is normal pressure to 0.3MPa, the esterification reaction temperature is 250-260 ℃, and the esterification reaction endpoint is determined when the distilled amount of water in the esterification reaction reaches more than 90% of a theoretical value;

(2) performing polycondensation reaction;

after the esterification reaction is finished, starting the polycondensation reaction in a low vacuum stage under the condition of negative pressure, wherein the pressure in the stage is stably pumped from normal pressure to below 500Pa in 30-50 min, the reaction temperature is 250-260 ℃, the reaction time is 30-50 min, then continuously pumping vacuum to perform the polycondensation reaction in a high vacuum stage, so that the reaction pressure is further reduced to below 100Pa, the reaction temperature is 270-282 ℃, and the reaction time is 50-90 min.

According to the preparation method of the semi-dull polyester low stretch yarn, the molar ratio of the terephthalic acid to the ethylene glycol to the fluorine-containing dibasic acid is 1: 1.2-2.0: 0.03-0.05, and the doped and modified ZrO is₂Powder and doped modified Sb₂O₃The addition amounts of the powder, the delustering agent and the stabilizer are respectively 0.04-0.07 wt%, 0.012-0.015 wt%, 0.20-0.25 wt% and 0.01-0.05 wt% (mass percentage) of the addition amount of the terephthalic acid. The amount of the fluorine-containing dibasic acid to be added is not limited thereto, and can be adjusted by those skilled in the art in the light of practical circumstancesHowever, the adjustment range is not too large, the excessive addition amount causes too large damage to the regularity of the polyester macromolecular structure, the influence on the crystallinity and the mechanical property of the fiber is too large, the production and the application of the fiber are not facilitated, and the too low addition amount causes an unobvious effect on the improvement of the degradation performance. The invention relates to a doped and modified ZrO₂The addition amount of the powder is not limited to this, and those skilled in the art can adjust the actual conditions, but the adjustment range is not too large, the excessive addition amount has a large influence on the gloss, the mechanical properties and the like of the fibers, and is not beneficial to the production and application of the fibers, and the excessive addition amount has an insignificant effect on the improvement of the degradation performance. Sb in polyester synthesis process in prior art₂O₃The amount of (A) is usually 0.02 to 0.04 wt% of the amount of terephthalic acid, and the amount of antimony-based catalyst is high, mainly due to undoped Sb₂O₃Activity per unit surface area r_sLow and specific surface area S_gSmall, therefore Sb₂O₃The overall catalytic activity is lower, and the invention is realized by the p-Sb₂O₃Doping modification is carried out to improve Sb₂O₃Thus significantly reducing Sb in the polyester synthesis process₂O₃The amount of (c) added.

According to the preparation method of the semi-dull polyester low stretch yarn, the flatting agent is titanium dioxide, and the stabilizing agent is triphenyl phosphate, trimethyl phosphate or trimethyl phosphite.

According to the preparation method of the semi-dull polyester low stretch yarn, the number average molecular weight of the modified polyester is 25000-30000, and the molecular weight distribution index is 1.8-2.2.

According to the preparation method of the semi-dull polyester low stretch yarn, the POY process comprises the following steps: metering, spinneret plate extrusion, cooling, oiling and winding;

the parameters of the POY process are as follows: the spinning temperature is 280-290 ℃, the cooling temperature is 18-22 ℃, and the winding speed is 3200-3600 m/min;

the DTY process comprises the following steps: carrying out thread guiding, heating and stretching, false twisting, heat setting and winding;

the DTY process has the following parameters: the spinning speed is 600-900 m/min, the setting overfeed rate is 3.5-5.5%, the winding overfeed rate is 2.5-5.0%, the temperature of the first hot box is 200-220 ℃, and the drawing ratio is 1.6-1.8. The specific parameters of the POY and DTY processes of the present invention are not limited in this regard and only one possible process parameter is set forth herein.

The semi-dull polyester low-stretch yarn prepared by the preparation method of the semi-dull polyester low-stretch yarn is modified polyester DTY yarn;

the molecular chain of the modified polyester comprises a terephthalic acid chain segment, an ethylene glycol chain segment and a fluorine-containing diacid chain segment;

the modified polyester is dispersed with a delustering agent and the doping modified ZrO₂Powder and the doped and modified Sb₂O₃The content of the flatting agent in the powder is 0.20-0.25 wt%.

As a preferred technical scheme:

the semi-dull polyester low-stretch yarn has the filament number of 0.5-1.5 dtex, the breaking strength of more than or equal to 3.5cN/dtex, the elongation at break of 25.0 +/-3.0%, the crimp shrinkage of 10.0 +/-1.0%, the crimp stability of more than or equal to 77%, the network degree of 95 +/-5/m, the linear density deviation rate of less than or equal to 2.0%, the breaking strength CV value of less than or equal to 8.0%, the elongation at break CV value of less than or equal to 8.0%, the crimp shrinkage variation coefficient CV value of less than or equal to 9.0%, and the boiling water shrinkage of 5.0 +/-0.5%, and the fluorine-containing dibasic acid and the doped and modified ZrO₂Powder and doping modified Sb₂O₃The addition amount of the powder is small, the influence on the processing and mechanical properties of the polyester fiber is small, and the processing property and mechanical properties of the polyester fiber are the same as those of common polyester fiber (no fluorine-containing dibasic acid is added, and the modified ZrO is doped)₂Powder and doping modified Sb₂O₃Powder) equivalent;

after the semi-dull polyester low stretch yarn is placed for 60 months at the temperature of 25 ℃ and the relative humidity of 65%, the intrinsic viscosity of the semi-dull polyester low stretch yarn is reduced by 15-18%, the intrinsic viscosity of the conventional PET fiber is reduced by less than 5% under the same condition, the natural degradation rate of the wool-like polyester filament yarn is remarkably increased compared with that of the conventional PET fiber, and the natural degradation rate of the wool-like polyester filament yarn is remarkably increased by using fluorine-containing dibasic acid and doped modified ZrO₂The addition of the powder can be remarkableThe natural degradation rate of the PET fiber is improved.

The invention mechanism is as follows:

the hydrolytic degradation process of polyester under alkaline condition is nucleophilic addition-elimination process, and OH is generated at the beginning of hydrolysis reaction^-Attack the C atom of ester carbonyl RCOOR ' to generate nucleophilic addition reaction to form intermediate (tetrahedral anion) which can eliminate OR ' to obtain carboxylic acid RCOOH and break ester bond, and OR ' and H⁺Binding to give alcohol HOR'. However, the degradation rate of polyester is slow because the anion structure of tetrahedron formed in the hydrolysis process is crowded, the steric hindrance is large, and the nucleophilic addition reaction is not facilitated.

The invention has promoted the process of nucleophilic addition reaction apparently through introducing the fluorine-containing dibasic acid of the special structure in the polyester molecular chain, and then has improved the degradation rate of the polyester, the special character of the fluorine-containing dibasic acid lies in α carbon, when introducing the fluorine-containing dibasic acid in the course of hydrolysis, because the fluorine atom is on α carbon, electron-withdrawing ability is stronger, make the electron cloud density on C-O bond in the polyester reduce, the stability of the anion of the tetrahedron is reduced, help the process of nucleophilic addition reaction, because the steric hindrance of the fluorine-containing dibasic acid on α carbon is smaller than terephthalic acid, have further promoted the process of nucleophilic addition reaction, therefore has obviously improved the degradation rate^-The reaction for attacking the ester carbonyl group to undergo nucleophilic addition has less influence.

When the polyester contains a certain amount of oxygen reduction catalyst, because the polyester is exposed in the air for a long time, oxygen in the air can permeate into the polyester through the free volume (narrow slit free volume and/or hollow free volume) in the polyester material, the surface of the oxygen reduction catalyst adsorbs the oxygen, the oxygen gradually migrates to the surface of the oxygen reduction catalyst in the polyester, the adsorbed oxygen is formed after a certain oxygen concentration gradient is reached, and the oxygen reduction catalyst is used for catalyzing and reducing the oxygenOxygen reduction reaction (oxygen ionization) is carried out on the surface of the oxidant, in the reaction process, oxygen is partially reduced into peroxide, oxygen molecules adsorbed by the oxygen reduction catalyst are bonded with ester in polyester to form RCOOOR 'on the surface of the catalyst, then a proton is bonded and oxygen-oxygen bond is broken to generate RCOOH, the ester bond is broken, and OR' and H are simultaneously used for breaking the ester bond⁺The alcohol HOR' is obtained by combination, thereby accelerating the degradation of the polyester.

The invention realizes the metal oxide (more than one of magnesium oxide, lithium oxide and zinc oxide) and ZrO by the method of solution blending, coprecipitation and calcination₂Doping of, and then to ZrO₂The oxygen reduction catalytic process has an influence, and the degradation rate of the polyester is improved. Because the invention selects ZrO with high ionic conductivity₂As oxygen reduction catalyst substrate by doping with metal ions (Mg) in lower valence state²⁺、Li⁺And Zn²⁺) Can obtain stable cubic phase, and to a certain extent, the closer the radius of doped ions is to the radius of the doped ions, the more favorable the formation of oxygen vacancies and the more favorable the conduction of oxygen ions, the doping and Zr are selected in the invention⁴⁺Metal ions (Mg) having the same ionic radius²⁺、Li⁺And Zn²⁺Ion radii of 0.103nm), which can increase the conduction rate of oxygen ions, thereby increasing the degree of oxygen reduction reaction. Doped p-ZrO₂The effect of (a) is as follows:

on the one hand, ZrO can be destroyed by adopting the doping mode of the invention₂The specific surface area is increased, and the unit mass ZrO is improved₂The amount of oxygen adsorption of (a);

on the other hand, ZrO can be changed by adopting the doping mode of the invention₂The adsorption mode and the oxygen reduction reaction mechanism are that before doping modification, the adsorption mode is monoclinic ZrO₂Terminal adsorption of the surface, O atoms at different monoclinic ZrO₂When crystal faces are adsorbed, the crystal faces are influenced by the steric hindrance effect of Zr atoms on the surfaces, and O is₂Molecules are adsorbed at Zr atom position by weak physical adsorption or weak chemical adsorption and are adsorbed at different monoclinic ZrO₂Crystal face O₂The molecules are reduced into peroxide, and after doping modification, the adsorption mode is ZrO doping₂Lateral adsorption of the surface, which is not affected by the "steric effect", enhances O₂The chemical adsorption of molecules at Zr atom position can also promote O₂Breaking of the O-O bond of the molecule, i.e. promoting O₂The molecules are reduced to generate peroxide, so that the oxygen reduction catalytic efficiency is improved, and the polyester degradation rate is further improved. Such as only mixing metal oxide (more than one of magnesium oxide, lithium oxide and zinc oxide) with ZrO₂Physical blending, the metal oxide does not influence ZrO₂The crystal face structure of the polyester can change the adsorption mode and the oxygen reduction reaction mechanism, so that the oxygen reduction catalysis efficiency can not be improved, and the polyester degradation rate can not be improved.

Due to the existence of the oxygen reduction catalyst in the polyester, oxygen can stay in the polyester for a long time, the weakest ester group in the polyester can be oxidized, and the degradation degree of the polyester is accelerated. The prior art degraded polyesters all start from the surface of the polyester, and the present invention provides a new idea of degradation from within the polyester by incorporating an oxygen reduction catalyst into the polyester.

The invention introduces fluorine-containing dibasic acid and doping modified ZrO in a polyester molecular chain₂The powder can also play a synergistic role, the fluorine-containing dibasic acid has stronger electron-withdrawing capability because the fluorine atom is on α carbon, so that the electron cloud density on the C-O bond in the polyester is reduced, the stability of tetrahedral negative ions is reduced, the degradation reaction is favorably carried out, and the doped modified ZrO₂The powder can improve the conduction rate of oxygen ions, accelerate the oxygen reduction reaction and further promote the degradation reaction, thereby further improving the natural degradation rate.

The invention also improves the polyester catalyst, improves the activity of the catalyst, reduces the dosage of the catalyst and saves the cost.

The prior polyester catalyst mainly takes antimony compounds such as antimony trioxide, ethylene glycol antimony and antimony acetate as main components, the addition amount of antimony in industrial polyester synthesis is more than 200ppm, the antimony is heavy metal, the age is advanced, the restriction on the antimony catalyst is more and more strict, and although titanium catalysis is applied, the antimony catalyst cannot be substituted for antimony in a short time due to various reasons such as color and activity control.

Catalytic activity of the catalyst and specific surface area S of the catalyst_gInternal surface utilization factor f and activity per surface area r_sProportional ratio, and for a certain component of the catalyst, the catalytic activity of the catalyst depends on the specific surface area S of the catalyst_gAnd the internal surface utilization factor f, the activity per unit surface area of the catalyst r_sAt a certain time, the larger the specific surface area, the higher the catalytic activity.

The invention realizes the doping and blending of the metal oxide and the antimony trioxide with certain catalytic polycondensation reaction activity by solution blending, coprecipitation and calcination, wherein the metal oxide is more than one of MgO, CaO, BaO and ZnO, the valence and the valence of the antimony are different, the ionic radius and the antimony are different, and the differences can change the crystal face structure of the antimony trioxide, thereby influencing the related performance. In addition, MgO, CaO, BaO and ZnO are all white crystals, and do not cause color change when used as a polyester catalyst.

The influence of the metal oxide on the antimony trioxide is mainly reflected in that: on the one hand, the metal oxide can inhibit crystallization of the antimony trioxide and growth of cubic antimony trioxide crystal grains, so that the specific surface area S of the antimony trioxide catalyst_gThe catalytic activity of the antimony trioxide is improved; on the other hand, the metal can isomorphously replace the antimony and enter the lattice site of the antimony, so that the antimony trioxide crystal generates defects, the crystal form is changed, the crystal grain size is reduced, and the specific surface area S is increased_gIncreasing the activity r per unit surface area of the crystal by enriching the metal on part of the crystal surface_sThe catalytic activity of the antimony trioxide is improved. If only the metal oxide with certain catalytic polycondensation reaction activity is simply and physically blended with the antimony trioxide, the catalytic activity of the antimony trioxide cannot be obviously improved, because the simple physical blending does not generate crystal defects, the crystal form does not change, the grain size remains unchanged, the total surface area of the crystal does not change, and the catalytic activity cannot be influenced.

According to the invention, the antimony trioxide is doped, so that the catalytic activity of the antimony trioxide is improved to a certain extent, the improvement of the catalytic activity of the antimony trioxide is beneficial to reducing the usage amount of the antimony trioxide, and in the polyester synthesis process, under the condition that the polycondensation process conditions are unchanged and the polyester achieves the same index, the usage amount of the antimony trioxide can be reduced by more than 30% after the antimony trioxide is doped by adopting the metal oxide, so that the problem of large addition amount of the existing antimony trioxide is effectively solved, and meanwhile, the requirement of polyester production can be met.

Has the advantages that:

(1) the preparation method of the semi-dull polyester low stretch yarn has simple process and low cost, and introduces fluorine-containing dibasic acid and doped modified ZrO into the polyester₂The powder modifies the polyester, so that the degradation performance of the fiber is obviously improved;

(2) according to the preparation method of the semi-dull polyester low stretch yarn, the antimony trioxide is doped and modified by the metal oxide with certain catalytic activity, so that the specific surface area S of the antimony trioxide is increased_gAnd activity per unit surface area r_sThereby improving the catalytic activity of the antimony trioxide and improving the polymerization efficiency; the addition amount of the antimony catalyst during polyester synthesis can be reduced while the production requirement of polyester is met, the antimony emission of the subsequently prepared fiber is effectively reduced, and the environment-friendly production is favorably realized;

(3) the semi-dull polyester low-stretch yarn disclosed by the invention is high in natural degradation rate, easy to degrade and recycle, good in mechanical property and good in application prospect, and the quality of the semi-dull polyester low-stretch yarn is not reduced.

Detailed Description

The invention will be further illustrated with reference to specific embodiments. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. Further, it should be understood that various changes or modifications of the present invention may be made by those skilled in the art after reading the teaching of the present invention, and such equivalents may fall within the scope of the present invention as defined in the appended claims.

Example 1

A preparation method of semi-dull polyester low stretch yarn comprises the following steps:

(1) preparing modified polyester;

(1.1) preparation of doping-modified Sb₂O₃；

(a) Mg (NO) was added at a concentration of 0.8 mol%₃)₂Aqueous solution with Sb concentration of 8 mol%₂O₃The solution of (A) is mixed uniformly, Sb₂O₃The solvent of the solution is oxalic acid, and Mg in the mixed solution²⁺And Sb³⁺In a molar ratio of 2: 100;

(b) dropwise adding 2mol/L ammonia water until the pH value of the mixed solution is 9 to obtain a precipitate, and then washing and drying the precipitate at 105 ℃ for 2.5 hours;

(c) heating the dried product to 400 ℃ firstly, then preserving heat for 2.5h, heating to 900 ℃ and then preserving heat for 1.5h, finally cooling in air and crushing to obtain the doped modified Sb with the average grain diameter of 0.4 micron₂O₃Powder;

(1.2) preparation of doped modified ZrO₂Powder;

(a) mg (NO) was added at a concentration of 1.5 wt%₃)₂Aqueous solution with 22 wt% ZrO₂The solution of (a) is mixed uniformly, ZrO₂The solvent of the solution is nitric acid, and Mg in the mixed solution²⁺With Zr⁴⁺In a molar ratio of 6: 100;

(b) dropwise adding ammonia water with the concentration of 2mol/L until the pH value of the mixed solution is 9 to obtain a precipitate, washing and drying the precipitate at the temperature of 108 ℃ for 2.5 hours;

(c) heating the dried product to 400 ℃, preserving heat for 2.5h, heating to 700 ℃, preserving heat for 1.5h, cooling in air, and crushing to obtain the doped modified ZrO with the particle size of 0.4 micron₂Powder;

(1.3) esterification reaction;

preparing terephthalic acid, ethylene glycol and 2, 2-difluoro-1, 3-malonic acid into slurry, adding doped modified ZrO₂Powder and doped modified Sb₂O₃Powder, dioxideTitanium and triphenyl phosphate are uniformly mixed, and then are pressurized in a nitrogen atmosphere to carry out esterification reaction, wherein the pressurizing pressure is 0.3MPa, the temperature of the esterification reaction is 250 ℃, the esterification reaction endpoint is when the distilled amount of water in the esterification reaction reaches 90 percent of a theoretical value, the molar ratio of terephthalic acid, ethylene glycol and 2, 2-difluoro-1, 3-malonic acid is 1:1.5:0.05, and the doped modified ZrO is₂Powder and doped modified Sb₂O₃The addition amounts of the powder, the titanium dioxide and the triphenyl phosphate are respectively 0.07 wt%, 0.012 wt%, 0.20 wt% and 0.01 wt% of the addition amount of the terephthalic acid;

(1.4) a polycondensation reaction;

after the esterification reaction is finished, starting the polycondensation reaction in a low vacuum stage under the negative pressure condition, wherein the pressure in the stage is stably pumped from normal pressure to absolute pressure 499Pa within 30min, the reaction temperature is 250 ℃, the reaction time is 30min, then continuing to pump vacuum, and carrying out the polycondensation reaction in a high vacuum stage, so that the reaction pressure is further reduced to absolute pressure 99Pa, the reaction temperature is 270 ℃, the reaction time is 50min, and the modified polyester with the number average molecular weight of 25000 and the molecular weight distribution index of 1.8 is prepared;

(2) preparing modified polyester POY (polyester pre-oriented yarn);

the modified polyester POY is obtained after the modified polyester melt is subjected to metering, spinneret plate extrusion, cooling, oiling and winding, and the parameters of the POY process are as follows: the spinning temperature is 285 ℃, the cooling temperature is 20 ℃, and the winding speed is 3200 m/min;

(3) preparing modified polyester DTY;

carrying out yarn guide, heating and stretching, false twisting, heat setting and winding on the modified polyester POY yarn to obtain modified polyester DTY yarn, namely the semi-dull polyester low stretch yarn, wherein the DTY process parameters are as follows: the spinning speed is 700m/min, the setting overfeed rate is 4.5 percent, the winding overfeed rate is 3 percent, the temperature of the first hot box is 210 ℃, the temperature of the second hot box is 170 ℃, and the drawing ratio is 1.7.

The filament number of the prepared semi-dull polyester low stretch yarn is 1.0dtex, the breaking strength is 3.5cN/dtex, the elongation at break is 22%, the crimp shrinkage is 9%, the crimp stability is 77%, the network degree is 95/m, the linear density deviation rate is 1.9%, the CV value of the breaking strength is 7.8%, the CV value of the elongation at break is 7.8%, the CV value of the variation coefficient of the crimp shrinkage is 8.8%, and the shrinkage in boiling water is 5.4%;

after the semi-dull polyester low stretch yarn is placed for 60 months under the conditions that the temperature is 25 ℃ and the relative humidity is 65%, the intrinsic viscosity of the semi-dull polyester low stretch yarn is reduced by 15%.

Comparative example 1

A preparation method of polyester yarns, which is basically consistent with the preparation method of the polyester yarns in the embodiment 1, and is different from the preparation method of the polyester yarns in that 2, 2-difluoro-1, 3-malonic acid and doped modified ZrO are not added in the step (1.3)₂And (3) powder. The filament number of the finally prepared polyester yarn is 1.0dtex, the breaking strength is 3.6cN/dtex, the elongation at break is 22.5%, the crimp shrinkage is 9%, the crimp stability is 77%, the network degree is 95/m, the linear density deviation rate is 1.9%, the CV value of the breaking strength is 7.5%, the CV value of the elongation at break is 7.5%, the CV value of the variation coefficient of the crimp shrinkage is 9.0%, and the shrinkage in boiling water is 5.5%; after the polyester yarn is placed for 60 months under the conditions that the temperature is 25 ℃ and the relative humidity is 65%, the intrinsic viscosity of the polyester yarn is reduced by 4%. Comparing example 1 with comparative example 1, the invention greatly improves the degradability of the polyester fiber by modifying the polyester, and the mechanical property is not affected.

Comparative example 2

A preparation method of polyester yarns, which is basically consistent with the preparation method of the polyester yarns in the embodiment 1, and is different from the preparation method of the polyester yarns in that 3, 3-difluoroglutaric acid is adopted to replace 2, 2-difluoro-1, 3-malonic acid in the step (1.3), and doped and modified ZrO is not added₂After the finally prepared polyester yarn is placed for 60 months under the conditions that the temperature is 25 ℃ and the relative humidity is 65%, the intrinsic viscosity of the finally prepared polyester yarn is reduced by 4.7%. Comparing example 1 with comparative example 1, it can be seen that the doped modified ZrO was not added₂When the powder and fluorine atom have electron-withdrawing group on β carbon of fluorine-containing dibasic acid with β carbon, the generated influence is only limited on adjacent carbon, and the influence on C-O bond in ester bond is small, thereby the OH is influenced^-The influence of the reaction of attacking ester carbonyl group for nucleophilic addition is small, and the influence on the natural degradation process of the fiber is small, so that the fluorine-containing dibasic acid with fluorine atoms at α carbon and the doped modified ZrO of the invention₂The powder is more beneficial to improving the natural degradation performance of the fiber.

Example 2

(1) preparing modified polyester;

(1.1) preparation of doping-modified Sb₂O₃；

(a) Ca (NO) was added at a concentration of 0.5 mol%₃)₂Aqueous solution with Sb concentration of 5 mol%₂O₃The solution of (A) is mixed uniformly, Sb₂O₃The solvent of the solution (A) is oxalic acid, and Ca is contained in the mixed solution²⁺And Sb³⁺In a molar ratio of 1: 100;

(b) dropwise adding 2mol/L ammonia water until the pH value of the mixed solution is 10 to obtain a precipitate, and then washing and drying the precipitate at the temperature of 110 ℃ for 2 hours;

(c) heating the dried product to 400 ℃ firstly, then preserving heat for 2h, heating to 900 ℃ and then preserving heat for 1h, finally cooling in air and crushing to obtain the doped modified Sb with the average grain diameter of 0.4 micron₂O₃Powder;

(1.2) preparation of doped modified ZrO₂Powder;

(a) LiNO was added at a concentration of 1 wt%₃Aqueous solution with 20 wt% ZrO₂The solution of (a) is mixed uniformly, ZrO₂The solvent of the solution is nitric acid, and Li in the mixed solution⁺With Zr⁴⁺In a molar ratio of 5: 100;

(b) dropwise adding ammonia water with the concentration of 2mol/L until the pH value of the mixed solution is 10 to obtain a precipitate, washing and drying the precipitate at the temperature of 105 ℃ for 3 hours;

(c) heating the dried product to 400 ℃, then preserving heat for 2h, then heating to 700 ℃, then preserving heat for 1h, finally cooling in air and crushing to obtain the doped modified ZrO with the grain size of 0.4 micron₂Powder;

(1.3) esterification reaction;

preparing terephthalic acid, ethylene glycol and 2, 2-difluoro-1, 4-succinic acid into slurry, adding doped modified ZrO₂Powder and doped modified Sb₂O₃Powder IITitanium oxide and trimethyl phosphate are uniformly mixed, then the mixture is pressurized in a nitrogen atmosphere to carry out esterification reaction, the pressurization pressure is normal pressure, the temperature of the esterification reaction is 260 ℃, the end point of the esterification reaction is when the distilled amount of water in the esterification reaction reaches 95 percent of a theoretical value, the molar ratio of terephthalic acid, ethylene glycol and 2, 2-difluoro-1, 4-succinic acid is 1:1.2.0:0.032, and the mixture is doped with modified ZrO₂Powder and doped modified Sb₂O₃The adding amount of the powder, the titanium dioxide and the trimethyl phosphate is respectively 0.04 wt%, 0.012 wt%, 0.25 wt% and 0.05 wt% of the adding amount of the terephthalic acid;

(1.4) a polycondensation reaction;

after the esterification reaction is finished, starting the polycondensation reaction in a low vacuum stage under the negative pressure condition, wherein the pressure in the stage is stably pumped from normal pressure to the absolute pressure of 450Pa within 50min, the reaction temperature is 260 ℃, the reaction time is 50min, then continuing to pump vacuum, and carrying out the polycondensation reaction in a high vacuum stage, so that the reaction pressure is further reduced to the absolute pressure of 90Pa, the reaction temperature is 282 ℃, the reaction time is 90min, and the modified polyester with the number average molecular weight of 30000 and the molecular weight distribution index of 2.2 is prepared;

(2) preparing modified polyester POY (polyester pre-oriented yarn);

the modified polyester POY is obtained after the modified polyester melt is subjected to metering, spinneret plate extrusion, cooling, oiling and winding, and the parameters of the POY process are as follows: the spinning temperature is 285 ℃, the cooling temperature is 22 ℃, and the winding speed is 2900 m/min;

(3) preparing modified polyester DTY;

The filament number of the prepared semi-dull polyester low stretch yarn is 0.5dtex, the breaking strength is 3.8cN/dtex, the elongation at break is 28%, the crimp shrinkage is 9%, the crimp stability is 82%, the network degree is 90/m, the linear density deviation rate is 1.8%, the CV value of the breaking strength is 7.2%, the CV value of the elongation at break is 7.2%, the CV value of the variation coefficient of the crimp shrinkage is 8.1%, and the shrinkage in boiling water is 4.5%;

Example 3

(1) preparing modified polyester;

(1.1) preparation of doping-modified Sb₂O₃；

(a) Ba (NO) was added at a concentration of 1.0 mol%₃)₂Aqueous solution with 10 mol% Sb₂O₃The solution of (A) is mixed uniformly, Sb₂O₃The solvent of the solution (A) is oxalic acid, and Ba in the mixed solution²⁺And Sb³⁺In a molar ratio of 3: 100;

(b) dropwise adding 2mol/L ammonia water until the pH value of the mixed solution is 9.5 to obtain a precipitate, and then washing and drying the precipitate at 105 ℃ for 3 h;

(c) heating the dried product to 400 ℃ firstly, then preserving heat for 3h, heating to 900 ℃ and then preserving heat for 2h, finally cooling in air and crushing to obtain the doped modified Sb with the average grain diameter of 0.5 micron₂O₃Powder;

(1.2) preparation of doped modified ZrO₂Powder;

(a) zn (NO) with a concentration of 2 wt%₃)₂Aqueous solution with 25 wt% ZrO₂The solution of (a) is mixed uniformly, ZrO₂The solvent of the solution (2) is nitric acid, and Zn is contained in the mixed solution²⁺With Zr⁴⁺In a molar ratio of 8: 100;

(b) dropwise adding ammonia water with the concentration of 2mol/L until the pH value of the mixed solution is 10 to obtain a precipitate, washing and drying the precipitate at the temperature of 110 ℃ for 2 hours;

(c) heating the dried product to 400 ℃, then preserving heat for 3h, then heating to 700 ℃, preserving heat for 2h, finally cooling in air and crushing to obtain the doped modified ZrO with the grain size of 0.4 micron₂Powder;

(1.3) esterification reaction;

preparing terephthalic acid, ethylene glycol and 2, 2-difluoro-1, 5-glutaric acid into slurry, adding doped modified ZrO₂Powder and doped modified Sb₂O₃Uniformly mixing the powder, titanium dioxide and trimethyl phosphite, pressurizing in a nitrogen atmosphere to perform esterification reaction, wherein the pressurizing pressure is 0.2MPa, the esterification reaction temperature is 255 ℃, the esterification reaction endpoint is when the distilled amount of water in the esterification reaction reaches 95% of a theoretical value, the molar ratio of terephthalic acid, ethylene glycol and 2, 2-difluoro-1, 5-glutaric acid is 1:1.5: 0.034, and doping modified ZrO₂Powder and doped modified Sb₂O₃The addition amounts of the powder, the titanium dioxide and the trimethyl phosphite are respectively 0.045 wt%, 0.013 wt%, 0.22 wt% and 0.03 wt% of the addition amount of the terephthalic acid;

(1.4) a polycondensation reaction;

after the esterification reaction is finished, starting the polycondensation reaction in the low vacuum stage under the negative pressure condition, stably pumping the pressure in the stage from normal pressure to absolute pressure of 480Pa within 40min, controlling the reaction temperature to be 255 ℃ and the reaction time to be 40min, then continuing to pump vacuum, and carrying out the polycondensation reaction in the high vacuum stage to further reduce the reaction pressure to absolute pressure of 95Pa, control the reaction temperature to be 272 ℃ and control the reaction time to be 70min, thus obtaining the modified polyester with the number average molecular weight of 27000 and the molecular weight distribution index of 2.0;

(2) preparing modified polyester POY (polyester pre-oriented yarn);

the modified polyester POY is obtained after the modified polyester melt is subjected to metering, spinneret plate extrusion, cooling, oiling and winding, and the parameters of the POY process are as follows: the spinning temperature is 285 ℃, the cooling temperature is 20 ℃, and the winding speed is 2900 m/min;

(3) preparing modified polyester DTY;

The filament number of the prepared semi-dull polyester low stretch yarn is 1.5dtex, the breaking strength is 3.8cN/dtex, the elongation at break is 27%, the crimp shrinkage is 10%, the crimp stability is 81%, the network degree is 100/m, the linear density deviation rate is 1.8%, the CV value of the breaking strength is 7.3%, the CV value of the elongation at break is 7.4%, the CV value of the variation coefficient of the crimp shrinkage is 8.2%, and the shrinkage in boiling water is 4.7%;

after the semi-dull polyester low stretch yarn is placed for 60 months under the conditions that the temperature is 25 ℃ and the relative humidity is 65%, the intrinsic viscosity of the semi-dull polyester low stretch yarn is reduced by 16%.

Example 4

(1) preparing modified polyester;

(1) preparation of doped modified Sb₂O₃；

(a) Zn (NO) was added at a concentration of 0.6 mol%₃)₂Aqueous solution with Sb concentration of 6 mol%₂O₃The solution of (A) is mixed uniformly, Sb₂O₃The solvent of the solution is oxalic acid, and Zn is contained in the mixed solution²⁺And Sb³⁺In a molar ratio of 1.2: 100;

(b) dropwise adding 2mol/L ammonia water until the pH value of the mixed solution is 10 to obtain a precipitate, and then washing and drying the precipitate at the temperature of 110 ℃ for 2.5 hours;

(c) heating the dried product to 400 ℃ firstly, then preserving heat for 2.5h, heating to 900 ℃ and then preserving heat for 1h, finally cooling in air and crushing to obtain the doped modified Sb with the average grain diameter of 0.4 micron₂O₃Powder;

(1.2) preparation of doped modified ZrO₂Powder;

(a) mg (NO) was added at a concentration of 1.2 wt%₃)₂Aqueous solution with 22 wt% ZrO₂The solution of (a) is mixed uniformly, ZrO₂The solvent of the solution is nitric acid, and Mg in the mixed solution²⁺With Zr⁴⁺In a molar ratio of 6: 100;

(b) dropwise adding ammonia water with the concentration of 2mol/L until the pH value of the mixed solution is 9 to obtain a precipitate, washing and drying the precipitate at the temperature of 106 ℃ for 2.5 hours;

(1.3) esterification reaction;

preparing terephthalic acid, ethylene glycol and 2, 2-difluoro-1, 5-glutaric acid into slurry, adding doped modified ZrO₂Powder and doped modified Sb₂O₃Uniformly mixing the powder, titanium dioxide and triphenyl phosphate, pressurizing in a nitrogen atmosphere to perform esterification reaction, wherein the pressurizing pressure is 0.25MPa, the esterification reaction temperature is 250 ℃, the esterification reaction endpoint is when the distilled amount of water in the esterification reaction reaches 95 percent of a theoretical value, the molar ratio of terephthalic acid, ethylene glycol and 2, 2-difluoro-1, 5-glutaric acid is 1:1.4:0.036, and the doped modified ZrO 2₂Powder and doped modified Sb₂O₃The adding amount of the powder, the titanium dioxide and the triphenyl phosphate is respectively 0.05 wt%, 0.014 wt%, 0.24 wt% and 0.04 wt% of the adding amount of the terephthalic acid;

(1.4) a polycondensation reaction;

after the esterification reaction is finished, starting the polycondensation reaction in a low vacuum stage under the negative pressure condition, stably pumping the pressure in the low vacuum stage from normal pressure to absolute pressure of 480Pa within 35min, controlling the reaction temperature to 258 ℃, controlling the reaction time to be 45min, then continuing to pump vacuum, and carrying out the polycondensation reaction in a high vacuum stage, so that the reaction pressure is further reduced to absolute pressure of 96Pa, the reaction temperature is 270 ℃, the reaction time is 55min, and the modified polyester with the number average molecular weight of 26000 and the molecular weight distribution index of 1.9 is prepared;

(2) preparing modified polyester POY (polyester pre-oriented yarn);

the modified polyester POY is obtained after the modified polyester melt is subjected to metering, spinneret plate extrusion, cooling, oiling and winding, and the parameters of the POY process are as follows: the spinning temperature is 280 ℃, the cooling temperature is 20 ℃, and the winding speed is 3200 m/min;

(3) preparing modified polyester DTY;

carrying out yarn guide, heating and stretching, false twisting, heat setting and winding on the modified polyester POY yarn to obtain modified polyester DTY yarn, namely the semi-dull polyester low stretch yarn, wherein the DTY process parameters are as follows: the spinning speed is 600m/min, the setting overfeed rate is 3.5 percent, the winding overfeed rate is 2.5 percent, the temperature of the first hot box is 200 ℃, the temperature of the second hot box is 160 ℃, and the drawing ratio is 1.6.

The filament number of the prepared semi-dull polyester low stretch yarn is 0.7dtex, the breaking strength is 3.7cN/dtex, the elongation at break is 26%, the crimp shrinkage is 10%, the crimp stability is 81%, the network degree is 95/m, the linear density deviation rate is 1.9%, the CV value of the breaking strength is 7.5%, the CV value of the elongation at break is 7.4%, the CV value of the variation coefficient of the crimp shrinkage is 8.4%, and the shrinkage in boiling water is 4.8%;

Example 5

(1) preparing modified polyester;

(1.1) preparation of doping-modified Sb₂O₃；

(a) Mg (NO) was added at a concentration of 0.7 mol%₃)₂Aqueous solution with Sb concentration of 8 mol%₂O₃The solution of (A) is mixed uniformly, Sb₂O₃The solvent of the solution is oxalic acid, and Mg in the mixed solution²⁺And Sb³⁺In a molar ratio of 2: 100;

(c) heating the dried product to 400 ℃ firstly, then preserving heat for 2.5h, heating to 900 ℃ and then preserving heat for 2h, finally cooling in air and crushing to obtain the doped modified Sb with the average grain diameter of 0.5 micron₂O₃Powder;

(1.2) preparation of doped modified ZrO₂Powder;

(a) LiNO was added at a concentration of 1.6 wt%₃Aqueous solution with a concentration of 24 wt%ZrO₂The solution of (a) is mixed uniformly, ZrO₂The solvent of the solution is nitric acid, and Li in the mixed solution⁺With Zr⁴⁺In a molar ratio of 7: 100;

(b) dropwise adding ammonia water with the concentration of 2mol/L until the pH value of the mixed solution is 9-10 to obtain a precipitate, washing and drying the precipitate at the temperature of 110 ℃ for 2 hours;

(c) heating the dried product to 400 ℃, then preserving heat for 3h, then heating to 700 ℃, preserving heat for 2h, finally cooling in air and crushing to obtain the doped modified ZrO with the grain size of 0.45 micron₂Powder;

(1.3) esterification reaction;

preparing terephthalic acid, ethylene glycol and 2,2,3, 3-tetrafluoro-1, 4-succinic acid into slurry, adding doped modified ZrO₂Powder and doped modified Sb₂O₃Uniformly mixing the powder, titanium dioxide and triphenyl phosphate, pressurizing in a nitrogen atmosphere to perform esterification reaction, wherein the pressurizing pressure is 0.15MPa, the esterification reaction temperature is 260 ℃, the esterification reaction endpoint is when the distilled amount of water in the esterification reaction reaches 94% of a theoretical value, the molar ratio of terephthalic acid, ethylene glycol and 2,2,3, 3-tetrafluoro-1, 4-succinic acid is 1:1.5:0.04, and the doped modified ZrO is prepared₂Powder and doped modified Sb₂O₃The adding amount of the powder, the titanium dioxide and the triphenyl phosphate is 0.055 wt%, 0.015 wt%, 0.25 wt% and 0.05 wt% of the adding amount of the terephthalic acid respectively;

(1.4) a polycondensation reaction;

after the esterification reaction is finished, starting the polycondensation reaction in the low vacuum stage under the negative pressure condition, smoothly pumping the pressure in the stage from normal pressure to absolute pressure of 480Pa within 50min, controlling the reaction temperature to be 255 ℃ and the reaction time to be 50min, then continuing pumping vacuum, and carrying out the polycondensation reaction in the high vacuum stage to further reduce the reaction pressure to absolute pressure of 95Pa, control the reaction temperature to be 282 ℃ and control the reaction time to be 80min, thus preparing the modified polyester with the number average molecular weight of 29000 and the molecular weight distribution index of 2.1;

(2) preparing modified polyester POY (polyester pre-oriented yarn);

the modified polyester POY is obtained after the modified polyester melt is subjected to metering, spinneret plate extrusion, cooling, oiling and winding, and the parameters of the POY process are as follows: the spinning temperature is 290 ℃, the cooling temperature is 18 ℃, and the winding speed is 2800 m/min;

(3) preparing modified polyester DTY;

the modified polyester POY yarn is processed by yarn guiding, heating and stretching, false twisting, heat setting and winding to obtain the modified polyester DTY yarn, namely the semi-dull polyester low stretch yarn, wherein the DTY process parameters are as follows: the spinning speed is 600m/min, the setting overfeed rate is 3.5 percent, the winding overfeed rate is 2.5 percent, the temperature of the first hot box is 200 ℃, the temperature of the second hot box is 160 ℃, and the drawing ratio is 1.6.

The filament number of the prepared semi-dull polyester low stretch yarn is 0.7dtex, the breaking strength is 3.7cN/dtex, the elongation at break is 26%, the crimp shrinkage is 10%, the crimp stability is 80%, the network degree is 95/m, the linear density deviation rate is 1.9%, the CV value of the breaking strength is 7.5%, the CV value of the elongation at break is 7.6%, the CV value of the variation coefficient of the crimp shrinkage is less than or equal to 9.0%, and the boiling water shrinkage is 4.9%;

after the semi-dull polyester low stretch yarn is placed for 60 months under the conditions that the temperature is 25 ℃ and the relative humidity is 65%, the intrinsic viscosity of the semi-dull polyester low stretch yarn is reduced by 16.5%.

Example 6

(1) preparing modified polyester;

(1.1) preparation of doping-modified Sb₂O₃；

(a) Mg (NO) was added at a concentration of 0.8 mol% in each case₃)₂Mixing the aqueous solution with Ca (NO)₃)₂Mixing the aqueous solutions according to the volume ratio of 1:1 to obtain the metal ion-containing N^y+Aqueous solution of (2), containing metal ions N^y+With 8 mol% Sb₂O₃The solution of (A) is mixed uniformly, Sb₂O₃The solvent of the solution is oxalic acid, and N in the mixed solution^y+And Sb³⁺In a molar ratio of 2.5: 100;

(b) dropwise adding 2mol/L ammonia water until the pH value of the mixed solution is 10 to obtain a precipitate, and then washing and drying the precipitate at 105 ℃ for 3 hours;

(c) heating the dried product to 400 ℃ firstly, then preserving heat for 3h, heating to 900 ℃ and then preserving heat for 1.5h, finally cooling in air and crushing to obtain the doped modified Sb with the average grain diameter of 0.4 micron₂O₃Powder;

(1.2) preparation of doped modified ZrO₂Powder;

(a) mg (NO) was added at a concentration of 2 wt% each₃)₂Aqueous solution and Zn (NO)₃)₂Mixing the aqueous solution according to the mass ratio of 1:1 to obtain M containing metal ions^x+Of a solution containing a metal ion M^x+With 20 wt% ZrO₂The solution of (a) is mixed uniformly, ZrO₂The solvent of the solution is nitric acid, and the metal ions M in the mixed solution^x+With Zr⁴⁺In a molar ratio of 8: 100;

(1.3) esterification reaction;

preparing terephthalic acid, ethylene glycol and 2,2,3, 3-tetrafluoro-1, 4-succinic acid into slurry, adding doped modified ZrO₂Powder and doped modified Sb₂O₃Uniformly mixing the powder, titanium dioxide and triphenyl phosphate, pressurizing in a nitrogen atmosphere to perform esterification reaction, wherein the pressurizing pressure is 0.3MPa, the esterification reaction temperature is 250 ℃, the esterification reaction endpoint is when the distilled amount of water in the esterification reaction reaches 94% of a theoretical value, the molar ratio of terephthalic acid, ethylene glycol and 2,2,3, 3-tetrafluoro-1, 4-succinic acid is 1:1.6:0.042, and the doped modified ZrO 2₂Powder and doped modified Sb₂O₃The addition amounts of the powder, the titanium dioxide and the triphenyl phosphate are respectively 0.059 wt%, 0.012 wt%, 0.20 wt% and 0.01 wt% of the addition amount of the terephthalic acid;

(1.4) a polycondensation reaction;

after the esterification reaction is finished, starting the polycondensation reaction in the low vacuum stage under the negative pressure condition, stably pumping the pressure in the stage from normal pressure to absolute pressure of 450Pa within 30min, controlling the reaction temperature to be 260 ℃ and the reaction time to be 30min, then continuing to pump vacuum, and carrying out the polycondensation reaction in the high vacuum stage to further reduce the reaction pressure to absolute pressure of 92Pa, controlling the reaction temperature to be 272 ℃ and the reaction time to be 85min, thus preparing the modified polyester with the number average molecular weight of 28000 and the molecular weight distribution index of 1.8;

(2) preparing modified polyester POY (polyester pre-oriented yarn);

(3) preparing modified polyester DTY;

carrying out yarn guide, heating and stretching, false twisting, heat setting and winding on the modified polyester POY yarn to obtain modified polyester DTY yarn, namely the semi-dull polyester low stretch yarn, wherein the DTY process parameters are as follows: the spinning speed is 900m/min, the setting overfeed rate is 5.5 percent, the winding overfeed rate is 5.0 percent, the first hot box temperature is 220 ℃, the second hot box temperature is 180 ℃, and the drawing ratio is 1.8.

The filament number of the prepared semi-dull polyester low stretch yarn is 1.2dtex, the breaking strength is 3.6cN/dtex, the elongation at break is 24%, the crimp shrinkage is 11%, the crimp stability is 79%, the network degree is 95/m, the linear density deviation rate is 1.9%, the CV value of the breaking strength is 7.6%, the CV value of the elongation at break is 7.6%, the CV value of the variation coefficient of the crimp shrinkage is 8.5%, and the shrinkage in boiling water is 5.1%;

after the semi-dull polyester low stretch yarn is placed for 60 months under the conditions that the temperature is 25 ℃ and the relative humidity is 65%, the intrinsic viscosity of the semi-dull polyester low stretch yarn is reduced by 17%.

Example 7

(1) preparing modified polyester;

(1.1) preparation of doping-modified Sb₂O₃；

(a) All concentrations are 0.5mol% Mg (NO)₃)₂Aqueous solution, Ba (NO)₃)₂Mixing the aqueous solution with Ca (NO)₃)₂Mixing the aqueous solution according to the volume ratio of 1:1:1 to obtain the metal ion-containing N^y+Aqueous solution of (2), containing metal ions N^y+With 10 mol% Sb₂O₃The solution of (A) is mixed uniformly, Sb₂O₃The solvent of the solution is oxalic acid, and the metal ion N in the mixed solution^y+And Sb³⁺In a molar ratio of 2: 100;

(b) dropwise adding 2mol/L ammonia water until the pH value of the mixed solution is 9 to obtain a precipitate, and then washing and drying the precipitate at 108 ℃ for 2.5 hours;

(c) heating the dried product to 400 ℃ firstly, then preserving heat for 2.5h, heating to 900 ℃ and then preserving heat for 2h, finally cooling in air and crushing to obtain the doped modified Sb with the average grain diameter of 0.4 micron₂O₃Powder;

(1.2) preparation of doped modified ZrO₂Powder;

(a) mg (NO) was added at a concentration of 1 wt% each₃)₂Aqueous solution, LiNO₃Aqueous solution and Zn (NO)₃)₂Mixing the aqueous solution according to the mass ratio of 1:1 to obtain M containing metal ions^x+Of a solution containing a metal ion M^x+With 24 wt% ZrO₂The solution of (a) is mixed uniformly, ZrO₂The solvent of the solution is nitric acid, and the metal ions M in the mixed solution^x+With Zr⁴⁺In a molar ratio of 6: 100;

(b) dropwise adding ammonia water with the concentration of 2mol/L until the pH value of the mixed solution is 10 to obtain a precipitate, washing and drying the precipitate at the temperature of 110 ℃ for 3 hours;

(c) heating the dried product to 400 ℃, then preserving heat for 2h, then heating to 700 ℃, preserving heat for 2h, finally cooling in air and crushing to obtain the doped modified ZrO with the grain size of 0.45 micron₂Powder;

(1.3) esterification reaction;

mixing terephthalic acid, ethylene glycol and 2, 2-difluoro-1, 3-malonic acid to form slurry, adding doping modifierZrO of nature₂Powder and doped modified Sb₂O₃Uniformly mixing the powder, titanium dioxide and triphenyl phosphate, pressurizing in a nitrogen atmosphere to perform esterification reaction, wherein the pressurizing pressure is 0.2MPa, the esterification reaction temperature is 255 ℃, the esterification reaction endpoint is when the distilled amount of water in the esterification reaction reaches 94% of a theoretical value, the molar ratio of terephthalic acid, ethylene glycol and 2, 2-difluoro-1, 3-malonic acid is 1:2.0:0.045, and the doped modified ZrO 2₂Powder and doped modified Sb₂O₃The addition amounts of the powder, the titanium dioxide and the triphenyl phosphate are respectively 0.064 wt%, 0.012 wt%, 0.20 wt% and 0.03 wt% of the addition amount of the terephthalic acid;

(1.4) a polycondensation reaction;

after the esterification reaction is finished, starting the polycondensation reaction in a low vacuum stage under the negative pressure condition, stably pumping the pressure in the stage from normal pressure to absolute pressure of 490Pa within 50min, controlling the reaction temperature to be 255 ℃ and the reaction time to be 50min, then continuing to pump vacuum, and carrying out the polycondensation reaction in a high vacuum stage to further reduce the reaction pressure to absolute pressure of 95Pa, control the reaction temperature to be 275 ℃ and control the reaction time to be 55min, thus preparing the modified polyester with the number average molecular weight of 25000 and the molecular weight distribution index of 2.2;

(2) preparing modified polyester POY (polyester pre-oriented yarn);

(3) preparing modified polyester DTY;

The single filament number of the prepared semi-dull polyester low stretch yarn is 1.2dtex, the breaking strength is 3.6cN/dtex, the elongation at break is 23%, the crimp shrinkage is 10.8%, the crimp stability is 78%, the network degree is 95/m, the linear density deviation rate is 2.0%, the CV value of the breaking strength is 7.9%, the CV value of the elongation at break is 8.0%, the CV value of the crimp shrinkage variation coefficient is 8.8%, and the shrinkage in boiling water is 5.4%;

Example 8

(1) preparing modified polyester;

(1.1) preparation of doping-modified Sb₂O₃；

(a) Mg (NO) was added at a concentration of 0.5 mol% in each case₃)₂Aqueous solution, Ba (NO)₃)₂Mixing the aqueous solution with Ca (NO)₃)₂Mixing the aqueous solution according to the volume ratio of 1:1:1 to obtain the metal ion-containing N^y+Aqueous solution of (2), containing metal ions N^y+With 10 mol% Sb₂O₃The solution of (A) is mixed uniformly, Sb₂O₃The solvent of the solution is oxalic acid, and the metal ion N in the mixed solution^y+And Sb³⁺In a molar ratio of 2: 100;

(1.2) preparation of doped modified ZrO₂Powder;

(a) mg (NO) was added at a concentration of 1 wt% each₃)₂Aqueous solution, LiNO₃Aqueous solution and Zn (NO)₃)₂Mixing the aqueous solution according to the mass ratio of 1:1 to obtain M containing metal ions^x+Of a solution containing a metal ion M^x+With 24 wt% ZrO₂The solution of (a) is mixed uniformly, ZrO₂Of the solution of (A)The agent is nitric acid, and the metal ions M in the mixed solution^x+With Zr⁴⁺In a molar ratio of 6: 100;

(1.3) esterification reaction;

preparing terephthalic acid, ethylene glycol and 2, 2-difluoro-1, 3-malonic acid into slurry, adding doped modified ZrO₂Powder and doped modified Sb₂O₃Uniformly mixing the powder, titanium dioxide and triphenyl phosphate, pressurizing in a nitrogen atmosphere to perform esterification reaction, wherein the pressurizing pressure is 0.3MPa, the esterification reaction temperature is 255 ℃, the esterification reaction endpoint is when the distilled amount of water in the esterification reaction reaches 96 percent of a theoretical value, the molar ratio of terephthalic acid, ethylene glycol and 2, 2-difluoro-1, 3-malonic acid is 1:2.0:0.048, and the doped modified ZrO 2₂Powder and doped modified Sb₂O₃The addition amounts of the powder, titanium dioxide and triphenyl phosphate are respectively 0.068 wt%, 0.013 wt%, 0.25 wt% and 0.03 wt% of the addition amount of terephthalic acid;

(1.4) a polycondensation reaction;

after the esterification reaction is finished, starting the polycondensation reaction in the low vacuum stage under the negative pressure condition, stably pumping the pressure in the stage from normal pressure to absolute pressure of 480Pa within 50min, controlling the reaction temperature to be 260 ℃ and the reaction time to be 40min, then continuously pumping vacuum to perform the polycondensation reaction in the high vacuum stage, further reducing the reaction pressure to absolute pressure of 95Pa, controlling the reaction temperature to be 272 ℃ and the reaction time to be 90min, and preparing the modified polyester with the number average molecular weight of 29000 and the molecular weight distribution index of 2.1;

(2) preparing modified polyester POY (polyester pre-oriented yarn);

the modified polyester POY is obtained after the modified polyester melt is subjected to metering, spinneret plate extrusion, cooling, oiling and winding, and the parameters of the POY process are as follows: the spinning temperature is 290 ℃, the cooling temperature is 20 ℃, and the winding speed is 3200 m/min;

(3) preparing modified polyester DTY;

carrying out yarn guide, heating and stretching, false twisting, heat setting and winding on the modified polyester POY yarn to obtain modified polyester DTY yarn, namely the semi-dull polyester low stretch yarn, wherein the DTY process parameters are as follows: the spinning speed is 800m/min, the setting overfeed rate is 5%, the winding overfeed rate is 4.0%, the temperature of the first hot box is 200 ℃, the temperature of the second hot box is 165 ℃ and the drawing ratio is 1.7.

The filament number of the prepared semi-dull polyester low stretch yarn is 1.0dtex, the breaking strength is 3.5cN/dtex, the elongation at break is 23%, the crimp shrinkage is 10%, the crimp stability is 77%, the network degree is 90/m, the linear density deviation rate is 1.9%, the CV value of the breaking strength is 8.0%, the CV value of the elongation at break is 8.0%, the CV value of the variation coefficient of the crimp shrinkage is 9.0%, and the shrinkage in boiling water is 5.5%;

after the semi-dull polyester low stretch yarn is placed for 60 months under the conditions that the temperature is 25 ℃ and the relative humidity is 65%, the intrinsic viscosity of the semi-dull polyester low stretch yarn is reduced by 18%.

Claims

1. The preparation method of the semi-dull polyester low stretch yarn is characterized by comprising the following steps: preparing modified polyester POY yarns from the modified polyester melt according to a POY process, and preparing modified polyester DTY yarns from the modified polyester POY yarns according to a DTY process to obtain semi-dull polyester low stretch yarns;

the content of the matting agent in the modified polyester is 0.20-0.25 wt%;

ZrO₂the doping modification process comprises the following steps: firstly, containing metal ions M^x+With Zr-containing solution⁴⁺The solution is mixed evenly and then the precipitant is added dropwise toThe pH value of the mixed solution is 9-10, and finally, a precipitate product is calcined;

metal ion M^x+Is Mg²⁺、Li⁺And Zn²⁺One or more of (1);

metal ion N^y+Is Mg²⁺、Ca²⁺、Ba²⁺And Zn²⁺One or more of (1);

the temperature of a second hot box of the DTY process is 160-180 ℃.

2. The method for preparing semi-dull polyester drawn textured yarn according to claim 1, wherein ZrO 2 is added₂When doping modification is carried out, the metal ions M are contained^x+The concentration of the solution is 1-2 wt%, the solvent is water, and the anion in the solution is NO₃ ^-(ii) a Said Zr containing⁴⁺The solution of (a) is 20-25 wt% ZrO₂The solvent of (1) is nitric acid; the precipitator is ammonia water with the concentration of 2 mol/L; at the beginning of precipitation, metal ion M in the mixture^x+With Zr⁴⁺The molar ratio of (A) to (B) is 5-8: 100; washing and drying the precipitate product before calcining, wherein the drying temperature is 105-110 ℃, and the drying time is 2-3 h; the calcining process comprises the following steps: firstly, heating to 400 ℃, then preserving heat for 2-3 h, then heating to 700 ℃, preserving heat for 1-2 h, and finally cooling in the air; ZrO (ZrO)₂After doping modification, crushing to obtain powder with average grain size less than 0.5 micron.

3. The method for preparing the semi-dull polyester drawn textured yarn as claimed in claim 2, wherein Sb is replaced by Sb₂O₃When doping modification is carried out, the metal ion N is contained^y+The concentration of the solution is 0.5-1.0 mol%, the solvent is water, and the anion in the solution is NO₃ ^-(ii) a The Sb-containing compound³⁺The solution of (a) is 5-10 mol% Sb₂O₃The solvent of (1) is oxalic acid; the precipitator is ammonia water with the concentration of 2 mol/L; at the beginning of precipitation, the metal ion N in the mixed solution^y+And Sb³⁺The molar ratio of (A) to (B) is 1-3: 100; washing and drying the precipitate product before calcining, wherein the drying temperature is 105-110 ℃, and the drying time is 2-3 h; the calcining process comprises the following steps: firstly, heating to 400 ℃, then preserving heat for 2-3 h, then heating to 900 ℃, preserving heat for 1-2 h, and finally cooling in the air; sb₂O₃After doping modification, crushing to obtain powder with average grain size less than 0.5 micron.

4. The preparation method of the semi-dull polyester drawn textured yarn according to claim 3, wherein the modified polyester is prepared by the following steps:

(1) performing esterification reaction;

(2) performing polycondensation reaction;

5. The preparation method of the semi-dull polyester drawn textured yarn according to claim 4, wherein the molar ratio of the terephthalic acid to the ethylene glycol to the fluorine-containing dibasic acid is 1: 1.2-2.0: 0.03-0.05, and the doped and modified ZrO is₂Powder, dopingModified Sb₂O₃The addition amounts of the powder, the delustering agent and the stabilizer are respectively 0.04-0.07 wt%, 0.012-0.015 wt%, 0.20-0.25 wt% and 0.01-0.05 wt% of the addition amount of the terephthalic acid.

6. The method for preparing the semi-dull polyester drawn textured yarn as claimed in claim 5, wherein the matting agent is titanium dioxide, and the stabilizer is triphenyl phosphate, trimethyl phosphate or trimethyl phosphite.

7. The preparation method of the semi-dull polyester drawn textured yarn according to claim 6, wherein the modified polyester has a number average molecular weight of 25000 to 30000 and a molecular weight distribution index of 1.8 to 2.2.

8. The preparation method of the semi-dull polyester drawn textured yarn as claimed in claim 1, wherein the POY process comprises the following steps: metering, spinneret plate extrusion, cooling, oiling and winding;

the DTY process has the following parameters: the spinning speed is 600-900 m/min, the setting overfeed rate is 3.5-5.5%, the winding overfeed rate is 2.5-5.0%, the temperature of the first hot box is 200-220 ℃, and the drawing ratio is 1.6-1.8.

9. The semi-dull polyester drawn textured yarn prepared by the method for preparing the semi-dull polyester drawn textured yarn according to any one of claims 1 to 8 is characterized in that: modified polyester DTY yarns;

the modified polyester is dispersed with a delustering agent and the doping modified ZrO₂Powder and the doped and modified Sb₂O₃Powder with the content of the flatting agent of0.20～0.25wt％。

10. The semi-dull polyester drawn textured yarn according to claim 9, wherein the semi-dull polyester drawn textured yarn has a single filament fineness of 0.5 to 1.5dtex, a breaking strength of 3.5cN/dtex or more, an elongation at break of 25.0. + -. 3.0%, a crimp shrinkage of 10.0. + -. 1.0%, a crimp stability of 77% or more, a network degree of 95. + -.5/m, a linear density deviation of 2.0% or less, a breaking strength CV value of 8.0% or less, an elongation at break CV value of 8.0% or less, a crimp shrinkage variation coefficient CV value of 9.0% or less, and a boiling water shrinkage of 5.0. + -. 0.5%;

after the semi-dull polyester low stretch yarn is placed for 60 months at the temperature of 25 ℃ and the relative humidity of 65%, the intrinsic viscosity of the semi-dull polyester low stretch yarn is reduced by 15-18%.