CN109735939B

CN109735939B - Melt direct spinning on-line addition colored polyester fiber and preparation method thereof

Info

Publication number: CN109735939B
Application number: CN201811615722.2A
Authority: CN
Inventors: 杨超明; 尹立新; 王丽丽
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: 2020-10-16
Anticipated expiration: 2038-12-27
Also published as: CN109735939A

Abstract

The invention relates to a melt direct spinning on-line adding colored polyester fiber and a preparation method thereof, wherein the preparation method comprises the following steps: combining the melt direct spinning online addition process with the FDY process, and preparing melt direct spinning online addition colored polyester fibers from the modified polyester melt according to the combined process; adding color master batches into the modified polyester melt on line in the melt direct spinning process; the prepared melt direct spinning on-line added colored polyester fiber is modified polyester FDY (fully drawn yarn), and the molecular chain of the modified polyester comprises a terephthalic acid chain segment, an ethylene glycol chain segment, a dibasic acid chain segment with a tert-butyl side group, a fluorine-containing dibasic acid chain segment and a 2,5,6, 6-tetramethyl-2, 5-heptanediol chain segment. The preparation method is simple, and the polyester is modified by the fluorine-containing dibasic acid, the dibasic acid with the tertiary butyl side group and the 2,5,6, 6-tetramethyl-2, 5-heptanediol, so that the hydrolysis rate of the polyester is increased, the natural degradation performance of the polyester fiber is improved, and the prepared product has excellent mechanical property.

Description

Melt direct spinning on-line addition colored polyester fiber and preparation method thereof

Technical Field

The invention belongs to the technical field of polyester fibers, and relates to a melt direct spinning on-line addition colored polyester fiber and a preparation method thereof.

Background

Polyethylene terephthalate (PET) is a polymer with excellent performance, and the PET has the advantages of high modulus, high strength, good shape retention, good barrier property and the like, so that the PET is widely applied to the fields of fibers, bottle packaging, films, sheets and the like, the yield is increased year by year, and the industrial position is remarkably improved.

At present, the fiber coloring of the textile industry mainly adopts the finishing dyeing of weaving firstly and then dyeing. Ordinary polyester staple fibers can be dyed by disperse dyes, but can be dyed only in the presence of a carrier at high temperature and high pressure, so that the damage to the fibers is large, the fastness of the dyeing such as light fastness, washing, ironing and the like is poor, and the energy consumption is large, the efficiency is low and the pollution is serious. The colored polyester fiber yarn obtained by directly spinning the polyester melt and the color master batch (toner) by the melt has good fastness properties such as soaping resistance, sunlight resistance and friction resistance, and the colored polyester fiber yarns with various colors enrich the selectivity of textile enterprises and become a preferred silk yarn material favored by consumers.

With the rapid development of the PET industry, although PET does not directly cause harm to the environment, PET waste has become a global organic pollutant for environmental pollution due to the huge number of waste products after use and strong resistance to atmospheric and microbial agents. At present, common treatment methods for PET wastes include landfill, incineration and recycling, although the landfill and the incineration are the simplest methods and cause certain pollution to the environment, degradation and recycling are effective and scientific approaches for treating the PET wastes, but because the PET has a compact structure, high crystallinity and long natural degradation time, the proportion of the recycling is very small at present. Based on the requirements of enhancement of environmental consciousness, resource conservation and sustainability, natural degradation of the polyester fiber is a problem which needs to be solved urgently by science and technology workers in China.

Therefore, the research on the method for improving the degradation rate and the degradation effect of the polyester by modifying the polyester has practical significance for preparing the melt direct spinning on-line addition colored polyester fiber with good mechanical property and low intrinsic viscosity by adopting the modified polyester.

Disclosure of Invention

The invention aims to overcome the defects of slow degradation rate and poor degradation effect of colored polyester fibers in the prior art, provides a method for improving the degradation rate and the degradation effect of polyester by modifying polyester, and prepares melt direct spinning on-line addition colored polyester fibers with good mechanical property and low intrinsic viscosity by adopting the modified polyester.

In order to achieve the purpose, the invention adopts the following technical scheme:

the melt direct spinning online additive colored polyester fiber preparation method comprises the steps of combining a melt direct spinning online addition process with an FDY process, and preparing modified polyester FDY yarns from a modified polyester melt according to the combined process to obtain melt direct spinning online additive colored polyester fibers;

adding color master batches into the modified polyester melt on line in the melt direct spinning process;

the preparation method of the modified polyester comprises the following steps: uniformly mixing terephthalic acid, ethylene glycol, dibasic acid with a tert-butyl side group, fluorine-containing dibasic acid and 2,5,6, 6-tetramethyl-2, 5-heptanediol, and then carrying out esterification reaction and polycondensation reaction in sequence;

the dibasic acid with tertiary butyl side group is 5-tertiary butyl-1, 3-phthalic acid, 2-tertiary butyl-1, 6-hexanedicarboxylic acid, 3-tertiary butyl-1, 6-hexanedicarboxylic acid or 2, 5-di-tertiary butyl-1, 6-hexanedicarboxylic acid; according to the invention, 5-tert-butyl-1, 3-phthalic acid, 2-tert-butyl-1, 6-hexanedicarboxylic acid, 3-tert-butyl-1, 6-hexanedicarboxylic acid or 2, 5-di-tert-butyl-1, 6-hexanedicarboxylic acid is used for modifying the polyester, so that the change of the activity of the main chain is easily caused, the interaction force among chain units is changed, the distance among the chain units is correspondingly changed, the cavity free volume of the modified polyester is increased, the difficulty of water molecules permeating into the modified polyester can be reduced due to the increase of the cavity free volume, and the natural degradation rate of the modified polyester is increased;

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 invention obviously improves the degradation rate of polyester by introducing the fluorine-containing dibasic acid with a special structure into a polyester molecular chain, and the fluorine-containing dibasic acid is characterized in that fluorine atoms are on alpha carbon, when the fluorine-containing dibasic acid is introduced in the hydrolysis process, because the fluorine atoms are on the alpha carbon, the electron-withdrawing capacity is strong, the electron cloud density on a C-O bond in the polyester is reduced, the stability of tetrahedron negative ions is reduced, the nucleophilic addition reaction is favorably carried out, and meanwhile, because the steric hindrance of the fluorine-containing dibasic acid on the alpha carbon is smaller than that of terephthalic acid, the nucleophilic addition reaction is further promoted, so the degradation rate is obviously improved.

The structural formula of the 2,5,6, 6-tetramethyl-2, 5-heptanediol is as follows:

according to the invention, the polyester is modified by the mutual matching of the 2,5,6, 6-tetramethyl-2, 5-heptanediol and the dibasic acid with the tert-butyl side group, the degradation rate of the polyester is obviously improved, and the change of the activity of the main chain is caused by the existence of the tert-butyl group in the 2,5,6, 6-tetramethyl-2, 5-heptanediol and the dibasic acid with the tert-butyl side group, so that the interaction force among chain units is changed, the distance among the chain units is correspondingly changed, and the free volume of the hollow cavity of the modified polyester is increased. Compared with short-chain substituent groups (such as methyl, ethyl and the like), the tertiary butyl group occupies a larger spatial position, and a larger free volume is obtained in the molecular chain arrangement mode; compared with the long-branched-chain substituent, on one hand, the tertiary butyl group has the increased free volume of a cavity, the long-branched-chain substituent has the increased free volume of a slit, and on the other hand, the rigidity of the tertiary butyl group is higher than that of the long-branched-chain substituent, so that entanglement among molecular chains is reduced, and the tertiary butyl group has more free volume than the long-branched-chain substituent in the arrangement mode of the molecular chains. The introduction of 2,5,6, 6-tetramethyl-2, 5-heptanediol and dibasic acid with tertiary butyl side group can increase the free volume of the hollow of the modified polyester, so that water or other molecules can easily permeate into the modified polyester macromolecule, and the degradation of the modified polyester is positively influenced.

As a preferred technical scheme:

according to the preparation method of the melt direct spinning on-line addition colored polyester fiber, the color master batch is composed of 20-30 wt% of pigment and 70-80 wt% of polyester, the mass ratio of the color master batch to the modified polyester melt is 1-3: 97-99, and the color of the pigment is red, yellow, blue, green, purple or black;

the synthesis method of the 2-tert-butyl-1, 6-hexanedicarboxylic acid, the 3-tert-butyl-1, 6-hexanedicarboxylic acid and the 2, 5-di-tert-butyl-1, 6-hexanedicarboxylic acid comprises the following steps:

firstly, mixing tungstic acid and hydrogen peroxide, stirring for 10-15 min at room temperature, then adding raw material alcohol, reacting for 1-2 h at the temperature of 80-85 ℃, then heating to 90-95 ℃ and reacting for 2-3 h, wherein reactants are always in a reflux state in the reaction process, and finally cooling, crystallizing, washing and refining;

when the reaction starts, the molar ratio of the tungstic acid to the raw material alcohol to the hydrogen peroxide is 1: 30-40: 120-150;

the raw material alcohols corresponding to the 2-tert-butyl-1, 6-hexanedicarboxylic acid, the 3-tert-butyl-1, 6-hexanedicarboxylic acid and the 2, 5-di-tert-butyl-1, 6-hexanedicarboxylic acid are respectively 2-tert-butylcyclohexanol, 4-tert-butylcyclohexanol and 2, 4-di-tert-butylcyclohexanol;

the synthesis steps of the 2,5,6, 6-tetramethyl-2, 5-heptanediol are as follows:

(1) mixing KOH powder, 3-methyl-3-hydroxybutyne, 3-dimethyl-2-butanone and isopropyl ether according to a molar ratio of 1-1.2: 1.2-1.3: 2.0-3.0, reacting for 2-4 hours under an ice bath condition, and after the reaction is finished, cooling, crystallizing, centrifugally separating, washing, refining and drying to obtain octynediol;

(2) mixing octynediol, ethanol and a palladium catalyst according to the weight ratio of 2-3: 10: 0.01-0.03, reacting at the temperature of 40-50 ℃ for 50-60 min, continuously introducing hydrogen during the reaction process, and separating and purifying after the reaction is finished to obtain 2,5,6, 6-tetramethyl-2, 5-heptanediol.

The preparation method of the melt direct spinning on-line additive colored polyester fiber comprises the following preparation steps:

(1) performing esterification reaction;

preparing terephthalic acid, ethylene glycol, dibasic acid with a tert-butyl side group, fluorine-containing dibasic acid and 2,5,6, 6-tetramethyl-2, 5-heptanediol into slurry, adding a catalyst, a delustering agent and a stabilizer, uniformly mixing, 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 end point of the esterification reaction is determined when the distilled amount of water in the esterification reaction reaches more than 90% of the 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.

The melt direct spinning online colored polyester fiber preparation method comprises the steps that the molar ratio of terephthalic acid to ethylene glycol is 1: 1.2-2.0, the sum of the addition amounts of dibasic acid with a tertiary butyl side group, fluorine-containing dibasic acid and 2,5,6, 6-tetramethyl-2, 5-heptanediol is 3-5 mol% (mol%) of the addition amount of terephthalic acid, the molar ratio of the dibasic acid with a tertiary butyl side group, fluorine-containing dibasic acid and 2,5,6, 6-tetramethyl-2, 5-heptanediol is 1-2: 2-4: 3-5, and the addition amounts of the catalyst, the delustering agent and the stabilizer are 0.03-0.05 wt%, 0.20-0.25 wt% and 0.01-0.05 wt% (mass%) of the addition amount of terephthalic acid respectively. The addition amounts of the dibasic acid with the tertiary butyl side group, the fluorine-containing dibasic acid and the 2,5,6, 6-tetramethyl-2, 5-heptanediol are not limited to the above, and a person skilled in the art can adjust the addition amounts according to actual conditions, but the adjustment range is not too large, the excessive addition amount has too large damage to the regularity of the polyester macromolecular structure, has too large influence on the crystallinity and the mechanical property of the fiber, and is not beneficial to the production and application of the fiber, and the effect is not obvious if the addition amount is too low.

According to the preparation method of the melt direct spinning online additive colored polyester fiber, the catalyst is antimony trioxide, ethylene glycol antimony or antimony acetate, the flatting agent is titanium dioxide, and the stabilizer is triphenyl phosphate, trimethyl phosphate or trimethyl phosphite.

The preparation method of the melt direct spinning on-line addition colored polyester fiber has the advantages that the number average molecular weight of the modified polyester is 25000-30000, and the molecular weight distribution index is 1.8-2.2

The preparation method of the melt direct spinning online additive colored polyester fiber comprises the following steps: before the melt enters the spinning manifold, injecting the color master batch after drying, melting, filtering and metering, and after fully and uniformly mixing the color master batch with the melt through a high-efficiency dynamic mixer, the color master batch and the melt jointly enter the spinning manifold;

the FDY process comprises the following steps: metering, spinneret plate extruding, cooling, oiling, stretching, heat setting and winding;

the FDY process comprises the following parameters: the spinning temperature is 285-295 ℃, the cooling temperature is 19-23 ℃, the network pressure is 0.20-0.30 MPa, the speed of one roller is 1800-2500 m/min, the temperature of one roller is 75-90 ℃, the speed of two rollers is 3600-4000 m/min, the temperature of two rollers is 105-125 ℃, and the winding speed is 3560-3920 m/min.

The invention also provides the melt direct spinning on-line additive colored polyester fiber prepared by the preparation method for the melt direct spinning on-line additive colored polyester fiber, which is modified polyester FDY yarn;

the molecular chain of the modified polyester comprises a terephthalic acid chain segment, a glycol chain segment, a dibasic acid chain segment with a tert-butyl side group, a fluorine-containing dibasic acid chain segment and a 2,5,6, 6-tetramethyl-2, 5-heptanediol chain segment.

As a preferred technical scheme:

the colored polyester fiber is added in the melt direct spinning online manner, the filament number of the colored polyester fiber added in the melt direct spinning online manner is 1.0-3.0 dtex, the breaking strength is more than or equal to 3.8cN/dtex, the breaking strength CV value is less than or equal to 5.0%, the elongation at break is 35 +/-4%, the elongation at break CV value is less than or equal to 9.0%, the boiling water shrinkage is 7.0 +/-0.5%, the yarn levelness CV value is less than or equal to 1.5%, the oil content is 1.00 +/-0.20 wt%, and the network degree is 20 +/-4/m. The polyester is modified by introducing dibasic acid with tertiary butyl side group, fluorine-containing dibasic acid and 2,5,6, 6-tetramethyl-2, 5-heptanediol, so that the mechanical property of the prepared fiber is not reduced and is equivalent to that of the prior art.

The colored polyester fiber is added in the melt direct spinning online manner, and the intrinsic viscosity of the melt direct spinning online colored polyester fiber is reduced by 15-20% after the melt direct spinning online colored polyester fiber is placed for 60 months under the conditions of 25 ℃ and 65% of relative humidity. The intrinsic viscosity of the conventional colored polyester fiber decreases by less than 5% under the same conditions. When the fluorine-containing dibasic acid is introduced into the polyester macromolecular chain, the fluorine atom is on the alpha carbon, the electron-withdrawing capability is strong, the nucleophilic addition reaction is promoted, the ester bond in the polyester macromolecular chain is broken, and the degradation rate is obviously improved.

The invention mechanism is as follows:

according to the invention, polyester is modified by using dibasic acid with tertiary butyl side groups, fluorine-containing dibasic acid and 2,5,6, 6-tetramethyl-2, 5-heptanediol, and the melt direct spinning online addition process is combined with the FDY process, so that the degradation performance and degradation effect of the prepared melt direct spinning online addition colored polyester fiber are greatly improved. Due to the fact that dibasic acid with tertiary butyl side groups and 2,5,6, 6-tetramethyl-2, 5-heptanediol are matched with each other to modify polyester, the cavity free volume of the modified polyester is increased, the difficulty of water molecules penetrating into the modified polyester can be reduced due to the increase of the cavity free volume, and the degradation rate of the modified polyester is improved; in addition, the polyester is modified by the fluorine-containing dibasic acid, so that the nucleophilic addition reaction can be promoted in the hydrolysis process, and the degradation rate is obviously improved.

The specific action mechanism of dibasic acid with tertiary butyl side group and 2,5,6, 6-tetramethyl-2, 5-heptanediol for improving the degradation performance of polyester fiber by modifying polyester is as follows:

the macromolecular chains in the polymer are not completely tightly packed, and voids always exist among the macromolecular chains, and the void volume is the free volume. Since small molecules are allowed to penetrate into the polymer, voids are sufficiently large in the polymer or between the polymers, the permeability and diffusivity of the small molecules are related to the size of the voids (i.e., the size of free volume) in the polymer structure, and within a certain range, the larger the size of the free volume, the higher the permeability of the small molecules, and the better the diffusivity. The free volume is divided into a cavity free volume and a slit free volume, the cavity free volume has larger space size than the slit free volume, and the effect of increasing the cavity free volume and increasing the slit free volume is more obvious for improving the permeability of small molecules.

The size and type of free volume depends mainly on the structure of the polymer, and the main factors influencing the structure of the polymer are steric hindrance, the size of the side group, the structure of the side group and the like. When a certain position on the main chain of the polymer is substituted by a side group, the activity change of the main chain is inevitably caused, so that the interaction force between chains is changed, the distance between the chains is also correspondingly changed, and consequently, the cohesive energy and the free volume are changed, and the polarity, the size, the length and the like of the substituent on the side chain of the macromolecule have certain influences on the rigidity of the molecular chain, the interaction between molecules and the free volume fraction of the polymer structure, so that the effects generated by different substituents are different, and the osmotic separation performance of the polymer is often different.

For isophthalic acid and hexadimethrineAcid, when H atom on benzene ring of isophthalic acid or H atom on methylene of adipic acid is replaced by methyl (-CH)₃) When in substitution, the C atoms on the side groups and the main chain C atoms are not in the same plane, so that four sp3 hybridized orbitals on the center C are respectively overlapped with empty orbitals on the four surrounding C atoms to form four completely same sigma bonds which are arranged in a regular tetrahedron, the four carbon atoms are respectively positioned at four vertexes of the regular tetrahedron, when three hydrogen of a methyl group is further substituted by the methyl group, the three hydrogen is equivalent to tert-butyl to be substituted to form a larger tetrahedron structure, molecular chains arranged in the regular tetrahedron are relatively arranged in a zigzag manner, the free volume of the empty holes is obviously increased by a lot, and the permeability and diffusivity of small molecules can be obviously improved; when the H atom on the benzene ring of the isophthalic acid or the H atom on the methylene of the adipic acid is replaced by the long branched chain substituent, the slit free volume is mainly increased, the increase amplitude is small, the improvement effect on the permeability and the diffusivity of the small molecule is limited, and meanwhile, the long branched chain substituent has small rigidity, the molecular chains are easy to tangle, and the increase of the free volume is not facilitated. The invention obviously improves the degradation performance of polyester by introducing dibasic acid with tert-butyl side groups into a polyester molecular chain, the dibasic acid with the tert-butyl side groups is 5-tert-butyl-1, 3-phthalic acid, 2-tert-butyl-1, 6-hexanedicarboxylic acid, 3-tert-butyl-1, 6-hexanedicarboxylic acid or 2, 5-di-tert-butyl-1, 6-hexanedicarboxylic acid, wherein the 2-tert-butyl-1, 6-hexanedicarboxylic acid, 3-tert-butyl-1, 6-hexanedicarboxylic acid and 2, 5-di-tert-butyl-1, 6-hexanedicarboxylic acid are adipic acid, are fatty acids, the rigidity of the fatty acids is less than that of the 5-tert-butyl-1, 3-phthalic acid, the improvement of the flexibility of a polyester chain segment is facilitated, and the existence of the tert-butyl group in the dibasic acid with the tert-butyl side groups can, therefore, the interaction force among the chain units is changed, and the distance among the chain units is correspondingly changed, so that the free volume of the hollow cavity of the modified polyester is increased. Compared with short-chain substituent groups (such as methyl, ethyl and the like), the tertiary butyl group occupies a larger spatial position, and a larger free volume is obtained in the molecular chain arrangement mode; in one aspect, the tertiary butyl groups have an increased void free volume compared to the long-chain substituentsThe increased free volume of the slit, on the other hand, the rigidity of the tertiary butyl group is greater than that of the long branched substituent, so that the entanglement among molecular chains is reduced, and the tertiary butyl group has more free volume than the long branched substituent in the arrangement mode of the molecular chains. In addition, when the dibasic acid with the tertiary butyl side group is 5-tertiary butyl-1, 3-phthalic acid, a benzene ring connected with the m-phthalic acid forms a larger asymmetric chain segment, so that the steric hindrance of migration between the chain segments is increased, the steric hindrance of rotation around a m-connection bond in the chain segment is increased, and the introduction of the m-isomer is favorable for increasing the free volume. The introduction of dibasic acid with tertiary butyl side group increases the free volume of the cavity of the modified polyester, and the increase of the free volume of the cavity enables water or other molecules to penetrate into macromolecules of the modified polyester more easily, thereby having positive influence on the degradation of the modified polyester and the like.

For glycol straight chain molecules such as ethylene glycol, butanediol and the like, C atoms on a main chain are arranged in a zigzag manner from top to bottom, and when two H atoms on a certain methylene on the main chain are replaced by methyl (-CH)₃) When in substitution, the C atoms on the two side groups and the main chain C atoms are not in the same plane, so that four sp3 hybridized orbitals on the center C are respectively overlapped with empty orbitals on the four surrounding C atoms to form four completely same sigma bonds which are arranged in a regular tetrahedron, the four carbon atoms are respectively positioned at four vertexes of the regular tetrahedron, when three hydrogen of a methyl group is further substituted by a methyl group, the three hydrogen is equivalent to tert-butyl to form a larger tetrahedron structure, compared with molecular chains arranged in a zigzag manner, the molecular chains arranged in the regular tetrahedron manner have the empty free volume which is obviously increased by a large amount, and the permeability and diffusivity of small molecules can be obviously improved; when two H atoms on a certain methylene on the main chain are replaced by the long branched chain substituent, the slit free volume is mainly increased, the increase amplitude is small, the improvement effect on the permeability and the diffusivity of small molecules is limited, and meanwhile, the long branched chain substituent has small rigidity, the molecular chains are easy to tangle, and the increase of the free volume is not facilitated. The existence of the tertiary butyl group in the 2,5,6, 6-tetramethyl-2, 5-heptanediol of the invention causes the change of the activity of the main chain, thereby changing the interaction force among chain units,the distance between molecular chain units is also changed correspondingly, so that the free volume of the hollow cavity of the modified polyester is increased. Compared with short-chain substituent groups (such as methyl, ethyl and the like), the tertiary butyl group occupies a larger spatial position, and a larger free volume is obtained in the molecular chain arrangement mode; compared with the long-branched-chain substituent, on one hand, the tertiary butyl group has the increased free volume of a cavity, the long-branched-chain substituent has the increased free volume of a slit, and on the other hand, the rigidity of the tertiary butyl group is higher than that of the long-branched-chain substituent, so that entanglement among molecular chains is reduced, and the tertiary butyl group has more free volume than the long-branched-chain substituent in the arrangement mode of the molecular chains. The free volume of the cavity is increased, so that water and the like can easily permeate into the modified polyester macromolecules, and the degradation and the like of the modified polyester are positively influenced.

The specific action mechanism of the fluorine-containing dibasic acid for modifying the polyester and improving the degradation performance of the polyester fiber 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 obviously improves the degradation rate of polyester by introducing the fluorine-containing dibasic acid with a special structure into a polyester molecular chain, the 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 C-O bonds in the polyester is reduced, the stability of tetrahedral anions is reduced, the nucleophilic addition reaction is favorably carried out, and meanwhile, the nucleophilic addition reaction is further promoted because the steric hindrance of the fluorine-containing dibasic acid on α carbon is less than that of terephthalic acid, so the degradation rate is obviously improvedThe fluorine-containing dibasic acid having a fluorine atom at β carbon does not significantly increase the degradation rate of the polyester because the presence of an electron-withdrawing group at β carbon has little effect on the C-O bond in the ester bond and thus on OH^-The reaction for attacking the ester carbonyl group to undergo nucleophilic addition has less influence. Although the on-line addition of colored polyester fibers in conventional melt direct spinning is widely applied, the fibers are compact in structure, high in crystallinity and long in natural degradation time, and are difficult to recycle when being used as main application of clothes.

Has the advantages that:

(1) according to the preparation method of the melt direct spinning on-line addition colored polyester fiber, the polyester is modified by adding the fluorine-containing dibasic acid, so that the nucleophilic addition reaction in the hydrolysis process is promoted, and meanwhile, the polyester is modified by the dibasic acid with the tert-butyl side group and the 2,5,6, 6-tetramethyl-2, 5-heptanediol, so that the free volume of the cavity of the modified polyester is increased, the degradation rate of the polyester is improved, and the preparation method can be used for clothing weaving and can effectively solve the problem of recycling of waste clothing;

(2) the preparation method of the melt direct spinning on-line addition colored polyester fiber has the advantages of simple process, low cost and wide application prospect;

(3) the melt direct spinning on-line addition colored polyester fiber has good mechanical property, and the intrinsic viscosity of the melt direct spinning on-line addition colored polyester fiber is reduced by 15-20% after the melt direct spinning on-line addition colored polyester fiber is placed for 60 months at 25 ℃ and under the relative humidity of 65%.

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

The preparation method of the melt direct spinning on-line addition colored polyester fiber comprises the following steps:

(1) preparing modified polyester;

(1.1) preparing 2,5,6, 6-tetramethyl-2, 5-heptanediol, wherein the synthesis method comprises the following steps:

(a) mixing KOH powder, 3-methyl-3-hydroxybutyne, 3-dimethyl-2-butanone and isopropyl ether according to the molar ratio of 1:1:1.2:2.0, reacting for 2 hours under the ice bath condition, and after the reaction is finished, cooling, crystallizing, centrifugally separating, washing, refining and drying to obtain octynediol;

(b) mixing octynediol, ethanol and a palladium catalyst according to the weight ratio of 2:10:0.01, reacting for 50min at the temperature of 40 ℃, continuously introducing hydrogen in the reaction process, and separating and purifying after the reaction is finished to obtain 2,5,6, 6-tetramethyl-2, 5-heptanediol, wherein the structural formula of the 2,5,6, 6-tetramethyl-2, 5-heptanediol is shown as a formula (I);

(1.2) esterification reaction;

preparing terephthalic acid, ethylene glycol, 5-tert-butyl-1, 3-phthalic acid, 2-difluoro-1, 3-malonic acid and 2,5,6, 6-tetramethyl-2, 5-heptanediol into slurry, adding antimony trioxide, titanium dioxide and triphenyl phosphate, uniformly mixing, pressurizing in a nitrogen atmosphere to perform esterification reaction, wherein the pressurizing pressure is normal pressure, the esterification reaction temperature is 250 ℃, the esterification reaction end point is determined when the distilled amount of water in the esterification reaction reaches 91% of a theoretical value, the molar ratio of the terephthalic acid to the ethylene glycol is 1:1.2, 5-tert-butyl-1, 3-phthalic acid, 2-difluoro-1, 3-malonic acid and 2,5,6, 6-tetramethyl-2, 5-heptanediol is 3 mol% of the added amount of the terephthalic acid, the molar ratio of 5-tert-butyl-1, 3-phthalic acid, 2-difluoro-1, 3-malonic acid and 2,5,6, 6-tetramethyl-2, 5-heptanediol was 1:2:4, and the amounts of antimony trioxide, titanium dioxide and triphenyl phosphate were 0.03 wt%, 0.20wt% and 0.04 wt%, respectively, of the amount of terephthalic acid added;

(1.3) a polycondensation reaction;

after the esterification reaction is finished, starting the polycondensation reaction in a low vacuum stage under the condition of negative pressure, stably pumping the pressure in the stage from normal pressure to the absolute pressure of 500Pa within 30min, controlling the reaction temperature to be 255 ℃ and the reaction time to be 30min, then continuing to pump vacuum, and carrying out the polycondensation reaction in a high vacuum stage to further reduce the reaction pressure to the absolute pressure of 100Pa, control the reaction temperature to be 270 ℃ and control the reaction time to be 40min, wherein the number average molecular weight of the prepared modified polyester is 26500 and the molecular weight distribution index is 1.8;

(2) combining a melt direct spinning online addition process with an FDY process, and preparing modified polyester FDY yarns from the modified polyester melt according to the combined process to obtain melt direct spinning online addition colored polyester fibers, wherein the melt direct spinning online addition process comprises the following steps: before the melt enters the spinning manifold, injecting the color master batch after drying, melting, filtering and metering, and after fully and uniformly mixing with the melt through a high-efficiency dynamic mixer, the color master batch and the melt jointly enter the spinning manifold, wherein the flow of the FDY process is as follows: metering, spinneret plate extruding, cooling, oiling, stretching, heat setting and winding, wherein the parameters of the FDY process are as follows: the spinning temperature is 285 ℃, the cooling temperature is 19 ℃, the network pressure is 0.25MPa, the one-roller speed is 2500m/min, the one-roller temperature is 80 ℃, the two-roller speed is 3600m/min, the two-roller temperature is 115 ℃, and the winding speed is 3920 m/min.

The filament number of the finally prepared melt direct spinning on-line additive colored polyester fiber is 1.0dtex, the breaking strength is 3.8cN/dtex, the CV value of the breaking strength is 4.3%, the elongation at break is 39%, the CV value of the elongation at break is 8.3%, the shrinkage in boiling water is 7.0%, the yarn levelness CV value is 1.49%, the oil content is 1.00 wt%, and the network degree is 18 pieces/m;

after the melt direct spinning on-line addition colored polyester fiber is placed for 60 months under the conditions of 25 ℃ and 65% of relative humidity, the intrinsic viscosity of the melt direct spinning on-line addition colored polyester fiber is reduced by 15%.

Comparative example 1

A method for preparing melt direct spinning on-line adding colored polyester fiber, the steps are basically the same as example 1, except that 5-tert-butyl-1, 3-phthalic acid, 2-difluoro-1, 3-malonic acid and 2,5,6, 6-tetramethyl-2, 5-heptanediol are not added in the step (1), i.e. the polyester is not modified, the melt direct spinning prepared by the method has the advantages that the filament number of the added colored polyester fiber is 1.0dtex, the breaking strength is 3.6cN/dtex, the breaking strength CV value is 4.4%, the breaking elongation is 38%, the breaking elongation CV value is 8.2%, the boiling water shrinkage is 6.7%, the yarn dry CV value is 1.40%, the oil content is 1.10 wt%, the network degree is 18/m, after the fiber is placed for 60 months under the conditions of 25 ℃ and 65% relative humidity, the intrinsic viscosity decreased by 3.6%. Compared with the example 1, the invention can find that the degradable performance of the fiber is improved by modifying the polyester through 5-tert-butyl-1, 3-phthalic acid, 2,5,6, 6-tetramethyl-2, 5-heptanediol and 2, 2-difluoro-1, 3-propanedioic acid, and the addition of the 5-tert-butyl-1, 3-phthalic acid, 2-difluoro-1, 3-propanedioic acid and 2,5,6, 6-tetramethyl-2, 5-heptanediol has little influence on other properties of the fiber and does not influence the processing performance and the mechanical properties of the fiber.

Comparative example 2

A method for preparing a melt direct spinning on-line colored polyester fiber, which comprises the steps substantially the same as those of example 1, except that 3, 3-difluoroglutaric acid is used instead of 2, 2-difluoro-1, 3-malonic acid in step (1), the melt direct spinning on-line colored polyester fiber is prepared, the filament number of the fiber is 1.0dtex, the breaking strength is 3.7cN/dtex, the CV value of the breaking strength is 4.3%, the elongation at break is 40%, the CV value of the elongation at break is 8.0%, the shrinkage of boiling water is 6.9%, the CV value of the yarn levelness is 1.36%, the oil content is 1.00 wt%, the network degree is 18/m, after 60 months of standing at a temperature of 25 ℃ and a relative humidity of 65%, the intrinsic viscosity is 4.7%, and compared with example 1, it can be found that fluorine atoms in a fluorine-containing dibasic acid of α carbons are more favorable for improving the natural degradation performance of the fiber compared with fluorine-containing dibasic acids of β carbons because the carbon atoms have little influence on the carbon bonds generated by the electron-withdrawing groups of β carbon atoms, and thus the adjacent OH-carbon bonds are generated in the carbon bonds generated by the O-3-2 carbon bonds^-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.

Example 2

(1) preparing modified polyester;

(1.1) preparation of 2-tert-butyl-1, 6-hexanedicarboxylic acid: firstly, mixing tungstic acid and hydrogen peroxide, stirring for 10min at room temperature, then adding 2-tert-butylcyclohexanol, reacting for 1h at the temperature of 80 ℃, heating to 94 ℃ for reaction for 2h, wherein reactants are always in a reflux state in the reaction process, and finally cooling, crystallizing, washing and refining, wherein the molar ratio of the tungstic acid to the 2-tert-butylcyclohexanol to the hydrogen peroxide is 1:35:120 at the beginning of the reaction;

(1.2) preparing 2,5,6, 6-tetramethyl-2, 5-heptanediol, wherein the synthesis method comprises the following steps:

(a) mixing KOH powder, 3-methyl-3-hydroxybutyne, 3-dimethyl-2-butanone and isopropyl ether according to the molar ratio of 1.1:1:1.2:2.3, reacting for 2 hours under the ice bath condition, and after the reaction is finished, cooling, crystallizing, centrifugally separating, washing, refining and drying to obtain octynediol;

(b) mixing octynediol, ethanol and a palladium catalyst according to the weight ratio of 2:10:0.01, reacting for 50min at the temperature of 45 ℃, continuously introducing hydrogen in the reaction process, and separating and purifying after the reaction is finished to obtain 2,5,6, 6-tetramethyl-2, 5-heptanediol, wherein the structural formula of the 2,5,6, 6-tetramethyl-2, 5-heptanediol is shown as a formula (I);

(1.3) esterification reaction;

preparing terephthalic acid, ethylene glycol, 2-tert-butyl-1, 6-hexanedioic acid, 2-difluoro-1, 4-butanedioic acid and 2,5,6, 6-tetramethyl-2, 5-heptanediol into slurry, adding antimony trioxide, titanium dioxide and trimethyl phosphite, uniformly mixing, pressurizing in a nitrogen atmosphere to perform esterification reaction, wherein the pressurizing pressure is 0.3MPa, the esterification reaction temperature is 260 ℃, the esterification reaction end point is determined when the distilled water amount in the esterification reaction reaches 92% of a theoretical value, the molar ratio of the terephthalic acid to the ethylene glycol is 1:1.5, 2-tert-butyl-1, 6-hexanedioic acid, 2-difluoro-1, 4-butanedioic acid and 2,5,6, 6-tetramethyl-2, 5-heptanediol is 3mol percent of the added amount of the terephthalic acid, the molar ratio of 2-tert-butyl-1, 6-hexanedicarboxylic acid, 2-difluoro-1, 4-butanedioic acid and 2,5,6, 6-tetramethyl-2, 5-heptanediol was 1:4:3, and the amounts of antimony trioxide, titanium dioxide and trimethyl phosphite were 0.04 wt%, 0.25wt% and 0.01 wt%, respectively, based on the amount of terephthalic acid added;

(1.4) a polycondensation reaction;

after the esterification reaction is finished, starting the polycondensation reaction in a low vacuum stage under the condition of negative pressure, stably pumping the pressure in the stage from normal pressure to absolute pressure of 400Pa within 40min, controlling the reaction temperature to be 250 ℃ and the reaction time to be 40min, 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 80Pa, control the reaction temperature to be 272 ℃ and control the reaction time to be 65min, wherein the number average molecular weight of the prepared modified polyester is 25000 and the molecular weight distribution index is 1.9;

(2) combining a melt direct spinning online addition process with an FDY process, and preparing modified polyester FDY yarns from the modified polyester melt according to the combined process to obtain melt direct spinning online addition colored polyester fibers, wherein the melt direct spinning online addition process comprises the following steps: before the melt enters the spinning manifold, injecting the color master batch after drying, melting, filtering and metering, and after fully and uniformly mixing with the melt through a high-efficiency dynamic mixer, the color master batch and the melt jointly enter the spinning manifold, wherein the flow of the FDY process is as follows: metering, spinneret plate extruding, cooling, oiling, stretching, heat setting and winding, wherein the parameters of the FDY process are as follows: the spinning temperature is 285 ℃, the cooling temperature is 23 ℃, the network pressure is 0.20MPa, the speed of one roller is 1900m/min, the temperature of one roller is 90 ℃, the speed of two rollers is 4000m/min, the temperature of two rollers is 125 ℃, and the winding speed is 3700 m/min.

The filament number of the finally prepared melt direct spinning on-line additive colored polyester fiber is 1.0dtex, the breaking strength is 4.1cN/dtex, the CV value of the breaking strength is 5.0%, the elongation at break is 35%, the CV value of the elongation at break is 8.7%, the shrinkage in boiling water is 6.5%, the yarn levelness CV value is 1.45%, the oil content is 0.80 wt%, and the network degree is 20/m;

after the melt direct spinning on-line addition colored polyester fiber is placed for 60 months under the conditions of 25 ℃ and 65% of relative humidity, the intrinsic viscosity of the fiber is reduced by 18%.

Example 3

(1) preparing modified polyester;

(1.1) preparation of 2-tert-butyl-1, 6-hexanedicarboxylic acid: firstly, mixing tungstic acid and hydrogen peroxide, stirring for 12min at room temperature, then adding 2-tert-butylcyclohexanol, reacting for 1.5h at 83 ℃, then heating to 90 ℃ for reacting for 2h, wherein reactants are always in a reflux state in the reaction process, and finally cooling, crystallizing, washing and refining, wherein the molar ratio of tungstic acid, 2-tert-butylcyclohexanol and hydrogen peroxide is 1:33:120 at the beginning of the reaction;

(a) mixing KOH powder, 3-methyl-3-hydroxybutyne, 3-dimethyl-2-butanone and isopropyl ether according to a molar ratio of 1.2:1:1.25:2.0, reacting for 3 hours under an ice bath condition, and after the reaction is finished, cooling, crystallizing, centrifugally separating, washing, refining and drying to obtain octynediol;

(b) mixing octynediol, ethanol and a palladium catalyst according to the weight ratio of 3:10:0.03, reacting for 50min at the temperature of 40 ℃, continuously introducing hydrogen in the reaction process, and separating and purifying after the reaction is finished to obtain 2,5,6, 6-tetramethyl-2, 5-heptanediol, wherein the structural formula of the 2,5,6, 6-tetramethyl-2, 5-heptanediol is shown as a formula (I);

(1.3) esterification reaction;

preparing terephthalic acid, ethylene glycol, 2-tert-butyl-1, 6-hexanedioic acid, 2-difluoro-1, 5-glutaric acid and 2,5,6, 6-tetramethyl-2, 5-heptanediol into slurry, adding ethylene glycol antimony, titanium dioxide and triphenyl phosphate, uniformly mixing, 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 end point is determined when the distilled water amount in the esterification reaction reaches 90% of a theoretical value, the molar ratio of the terephthalic acid to the ethylene glycol is 1:1.3, 2-tert-butyl-1, 6-hexanedioic acid, 2-difluoro-1, 5-glutaric acid and 2,5,6, 6-tetramethyl-2, 5-heptanediol is 3.5 mol% of the added amount of the terephthalic acid, the molar ratio of 2-tert-butyl-1, 6-hexanedicarboxylic acid, 2-difluoro-1, 5-glutaric acid and 2,5,6, 6-tetramethyl-2, 5-heptanediol was 1.5:2:3, and the amounts of ethylene glycol antimony, titanium dioxide and triphenyl phosphate were 0.04 wt%, 0.22 wt% and 0.05wt%, respectively, of 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 45min, the reaction temperature is 256 ℃, 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 100Pa, the reaction temperature is 279 ℃, the reaction time is 60min, the number average molecular weight of the prepared modified polyester is 28000, and the molecular weight distribution index is 2.2;

(2) combining a melt direct spinning online addition process with an FDY process, and preparing modified polyester FDY yarns from the modified polyester melt according to the combined process to obtain melt direct spinning online addition colored polyester fibers, wherein the melt direct spinning online addition process comprises the following steps: before the melt enters the spinning manifold, injecting the color master batch after drying, melting, filtering and metering, and after fully and uniformly mixing with the melt through a high-efficiency dynamic mixer, the color master batch and the melt jointly enter the spinning manifold, wherein the flow of the FDY process is as follows: metering, spinneret plate extruding, cooling, oiling, stretching, heat setting and winding, wherein the parameters of the FDY process are as follows: the spinning temperature is 290 ℃, the cooling temperature is 19 ℃, the network pressure is 0.20MPa, the speed of one roller is 1800m/min, the temperature of one roller is 90 ℃, the speed of two rollers is 3800m/min, the temperature of two rollers is 120 ℃, and the winding speed is 3920 m/min.

The filament number of the finally prepared melt direct spinning on-line additive colored polyester fiber is 2.0dtex, the breaking strength is 3.8cN/dtex, the CV value of the breaking strength is 5.0%, the elongation at break is 31%, the CV value of the elongation at break is 9.0%, the shrinkage in boiling water is 7.5%, the yarn levelness CV value is 1.46%, the oil content is 1.20 wt%, and the network degree is 16/m;

after the melt direct spinning on-line addition colored polyester fiber is placed for 60 months under the conditions of 25 ℃ and 65% of relative humidity, the intrinsic viscosity of the melt direct spinning on-line addition colored polyester fiber is reduced by 17%.

Example 4

(1) preparing modified polyester;

(1.1) preparation of 3-tert-butyl-1, 6-hexanedicarboxylic acid: firstly, mixing tungstic acid and hydrogen peroxide, stirring for 13min at room temperature, then adding 4-tert-butylcyclohexanol, reacting for 2h at the temperature of 85 ℃, heating to 90 ℃ and reacting for 3h, wherein reactants are always in a reflux state in the reaction process, and finally cooling, crystallizing, washing and refining, wherein the molar ratio of the tungstic acid to the 4-tert-butylcyclohexanol to the hydrogen peroxide is 1:30:130 at the beginning of the reaction;

(a) mixing KOH powder, 3-methyl-3-hydroxybutyne, 3-dimethyl-2-butanone and isopropyl ether according to a molar ratio of 1.2:1:1.3:2.5, reacting for 3 hours under an ice bath condition, and after the reaction is finished, cooling, crystallizing, centrifugally separating, washing, refining and drying to obtain octynediol;

(b) mixing octynediol, ethanol and a palladium catalyst according to the weight ratio of 2.5:10:0.02, reacting for 60min at the temperature of 45 ℃, continuously introducing hydrogen in the reaction process, and separating and purifying after the reaction is finished to obtain 2,5,6, 6-tetramethyl-2, 5-heptanediol, wherein the structural formula of the 2,5,6, 6-tetramethyl-2, 5-heptanediol is shown as a formula (I);

(1.3) esterification reaction;

preparing terephthalic acid, ethylene glycol, 3-tert-butyl-1, 6-hexanedioic acid, 2,3, 3-tetrafluoro-1, 4-butanedioic acid and 2,5,6, 6-tetramethyl-2, 5-heptanediol into slurry, adding ethylene glycol antimony, titanium dioxide and trimethyl phosphite, uniformly mixing, pressurizing in a nitrogen atmosphere to perform esterification reaction, wherein the pressurizing pressure is 0.1MPa, the esterification reaction temperature is 250 ℃, the esterification reaction endpoint is when the distilled water amount in the esterification reaction reaches 90% of a theoretical value, the molar ratio of the terephthalic acid to the ethylene glycol is 1:1.8, 3-tert-butyl-1, 6-hexanedioic acid, 2,3, 3-tetrafluoro-1, 4-butanedioic acid and 2,5,6, 6-tetramethyl-2, the sum of the addition amounts of the 5-heptanediols is 4 mol% of the addition amount of the terephthalic acid, the molar ratio of the 3-tert-butyl-1, 6-hexanedioic acid, the 2,2,3, 3-tetrafluoro-1, 4-succinic acid and the 2,5,6, 6-tetramethyl-2, 5-heptanediols is 1.5:3:5, and the addition amounts of the ethylene glycol antimony, the titanium dioxide and the trimethyl phosphite are 0.05wt%, 0.20wt% and 0.03 wt% of the addition amount of the terephthalic acid, respectively;

(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 420Pa within 50min, controlling the reaction temperature to be 260 ℃ and the reaction time to be 35min, 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 85Pa, the reaction temperature is 280 ℃ and the reaction time is 40min, wherein the number average molecular weight of the prepared modified polyester is 27700, and the molecular weight distribution index is 1.8;

(2) combining a melt direct spinning online addition process with an FDY process, and preparing modified polyester FDY yarns from the modified polyester melt according to the combined process to obtain melt direct spinning online addition colored polyester fibers, wherein the melt direct spinning online addition process comprises the following steps: before the melt enters the spinning manifold, injecting the color master batch after drying, melting, filtering and metering, and after fully and uniformly mixing with the melt through a high-efficiency dynamic mixer, the color master batch and the melt jointly enter the spinning manifold, wherein the flow of the FDY process is as follows: metering, spinneret plate extruding, cooling, oiling, stretching, heat setting and winding, wherein the parameters of the FDY process are as follows: the spinning temperature is 292 ℃, the cooling temperature is 22 ℃, the network pressure is 0.30MPa, the one-roller speed is 1800m/min, the one-roller temperature is 85 ℃, the two-roller speed is 3800m/min, the two-roller temperature is 110 ℃, and the winding speed is 3560 m/min.

The filament number of the finally prepared melt direct spinning on-line additive colored polyester fiber is 1.8dtex, the breaking strength is 4.1cN/dtex, the CV value of the breaking strength is 4.3%, the elongation at break is 31%, the CV value of the elongation at break is 9.0%, the shrinkage in boiling water is 7.5%, the yarn levelness CV value is 1.47%, the oil content is 0.90 wt%, and the network degree is 24/m;

after the melt direct spinning on-line addition colored polyester fiber is placed for 60 months under the conditions of 25 ℃ and 65% of relative humidity, the intrinsic viscosity of the fiber is reduced by 20%.

Example 5

(1) preparing modified polyester;

(1.1) preparation of 3-tert-butyl-1, 6-hexanedicarboxylic acid: firstly, mixing tungstic acid and hydrogen peroxide, stirring for 14min at room temperature, then adding 4-tert-butylcyclohexanol, reacting for 2h at the temperature of 82 ℃, then heating to 92 ℃ for reacting for 3h, wherein reactants are always in a reflux state in the reaction process, and finally cooling, crystallizing, washing and refining, wherein the molar ratio of the tungstic acid to the 4-tert-butylcyclohexanol to the hydrogen peroxide is 1:40:130 at the beginning of the reaction;

(a) mixing KOH powder, 3-methyl-3-hydroxybutyne, 3-dimethyl-2-butanone and isopropyl ether according to the molar ratio of 1:1:1.3:3.0, reacting for 4 hours under the ice bath condition, and after the reaction is finished, cooling, crystallizing, centrifugally separating, washing, refining and drying to obtain octynediol;

(b) mixing octynediol, ethanol and a palladium catalyst according to the weight ratio of 2.5:10:0.02, reacting for 55min at the temperature of 50 ℃, continuously introducing hydrogen in the reaction process, and separating and purifying after the reaction is finished to obtain 2,5,6, 6-tetramethyl-2, 5-heptanediol, wherein the structural formula of the 2,5,6, 6-tetramethyl-2, 5-heptanediol is shown as a formula (I);

(1.3) esterification reaction;

preparing terephthalic acid, ethylene glycol, 3-tert-butyl-1, 6-hexanedioic acid, 2-difluoro-1, 3-malonic acid and 2,5,6, 6-tetramethyl-2, 5-heptanediol into slurry, adding antimony acetate, titanium dioxide and trimethyl phosphate, uniformly mixing, pressurizing in a nitrogen atmosphere to perform esterification reaction, wherein the pressurizing pressure is 0.3MPa, the esterification reaction temperature is 252 ℃, the esterification reaction end point is determined when the distilled amount of water in the esterification reaction reaches 90% of a theoretical value, the molar ratio of the terephthalic acid to the ethylene glycol is 1:2.0, the addition amount of the 3-tert-butyl-1, 6-hexanedioic acid, 2-difluoro-1, 3-malonic acid and 2,5,6, 6-tetramethyl-2, 5-heptanediol is 4mol percent of the addition amount of the terephthalic acid, the molar ratio of 3-tert-butyl-1, 6-hexanedicarboxylic acid, 2-difluoro-1, 3-malonic acid and 2,5,6, 6-tetramethyl-2, 5-heptanediol was 2:3:4, and the amounts of antimony acetate, titanium dioxide and trimethyl phosphate added were 0.03 wt%, 0.24 wt% and 0.04 wt%, respectively, of the amount of terephthalic acid added;

(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 the absolute pressure of 500Pa within 30min, controlling the reaction temperature to be 256 ℃ and the reaction time to be 45min, then continuing to pump the vacuum, and carrying out the polycondensation reaction in the high vacuum stage, so that the reaction pressure is further reduced to the absolute pressure of 88Pa, the reaction temperature is 278 ℃, the reaction time is 75min, and the number average molecular weight of the prepared modified polyester is 29000 and the molecular weight distribution index is 2.0;

(2) combining a melt direct spinning online addition process with an FDY process, and preparing modified polyester FDY yarns from the modified polyester melt according to the combined process to obtain melt direct spinning online addition colored polyester fibers, wherein the melt direct spinning online addition process comprises the following steps: before the melt enters the spinning manifold, injecting the color master batch after drying, melting, filtering and metering, and after fully and uniformly mixing with the melt through a high-efficiency dynamic mixer, the color master batch and the melt jointly enter the spinning manifold, wherein the flow of the FDY process is as follows: metering, spinneret plate extruding, cooling, oiling, stretching, heat setting and winding, wherein the parameters of the FDY process are as follows: the spinning temperature is 295 ℃, the cooling temperature is 21 ℃, the network pressure is 0.23MPa, the speed of one roller is 2500m/min, the temperature of one roller is 85 ℃, the speed of two rollers is 3600m/min, the temperature of two rollers is 105 ℃, and the winding speed is 3560 m/min.

The filament number of the finally prepared melt direct spinning on-line additive colored polyester fiber is 3.0dtex, the breaking strength is 4.0cN/dtex, the CV value of the breaking strength is 4.8%, the elongation at break is 39%, the CV value of the elongation at break is 8.0%, the shrinkage in boiling water is 6.8%, the yarn levelness CV value is 1.4%, the oil content is 0.80 wt%, and the network degree is 20/m;

after the melt direct spinning on-line addition colored polyester fiber is placed for 60 months under the conditions of 25 ℃ and 65% of relative humidity, the intrinsic viscosity of the melt direct spinning on-line addition colored polyester fiber is reduced by 19%.

Example 6

(1) preparing modified polyester;

(1.1) preparation of 2, 5-di-tert-butyl-1, 6-hexanedicarboxylic acid: firstly, mixing tungstic acid and hydrogen peroxide, stirring for 15min at room temperature, then adding 2, 4-di-tert-butylcyclohexanol, reacting for 1.5h at 83 ℃, then heating to 92 ℃ and reacting for 2.5h, wherein reactants are always in a reflux state in the reaction process, and finally cooling, crystallizing, washing and refining, wherein the molar ratio of the tungstic acid to the 2, 4-di-tert-butylcyclohexanol to the hydrogen peroxide is 1:40:120 when the reaction starts;

(a) mixing KOH powder, 3-methyl-3-hydroxybutyne, 3-dimethyl-2-butanone and isopropyl ether according to a molar ratio of 1.1:1:1.2:3.0, reacting for 4 hours under an ice bath condition, and after the reaction is finished, cooling, crystallizing, centrifugally separating, washing, refining and drying to obtain octynediol;

(b) mixing octynediol, ethanol and a palladium catalyst according to the weight ratio of 3:10:0.03, reacting for 60min at the temperature of 50 ℃, continuously introducing hydrogen in the reaction process, and separating and purifying after the reaction is finished to obtain 2,5,6, 6-tetramethyl-2, 5-heptanediol, wherein the structural formula of the 2,5,6, 6-tetramethyl-2, 5-heptanediol is shown as a formula (I);

(1.3) esterification reaction;

preparing terephthalic acid, ethylene glycol, 2, 5-di-tert-butyl-1, 6-hexanedioic acid, 2-difluoro-1, 4-butanedioic acid and 2,5,6, 6-tetramethyl-2, 5-heptanediol into slurry, adding antimony trioxide, titanium dioxide and triphenyl phosphate, uniformly mixing, pressurizing in a nitrogen atmosphere to perform esterification reaction, wherein the pressurizing pressure is normal pressure, the esterification reaction temperature is 260 ℃, the esterification reaction end point is determined when the distilled water amount in the esterification reaction reaches 95% of a theoretical value, the molar ratio of the terephthalic acid to the ethylene glycol is 1:1.6, 2, 5-di-tert-butyl-1, 6-hexanedioic acid, 2-difluoro-1, 4-butanedioic acid and 2,5,6, 6-tetramethyl-2, 5-heptanediol is 5mol% of the added amount of the terephthalic acid, the molar ratio of 2, 5-di-tert-butyl-1, 6-hexanedicarboxylic acid, 2-difluoro-1, 4-butanedioic acid and 2,5,6, 6-tetramethyl-2, 5-heptanediol was 2:4:5, and the amounts of antimony trioxide, titanium dioxide and triphenyl phosphate added were 0.05wt%, 0.25wt% and 0.05wt%, respectively, of the amount of terephthalic acid added;

(1.4) a polycondensation reaction;

after the esterification reaction is finished, starting the polycondensation reaction in a low vacuum stage under the condition of negative pressure, smoothly pumping the pressure in the stage from normal pressure to absolute pressure of 490Pa within 30min, controlling the reaction temperature to be 260 ℃ 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 90Pa, control the reaction temperature to be 282 ℃ and control the reaction time to be 55min, wherein the number average molecular weight of the prepared modified polyester is 30000 and the molecular weight distribution index is 2.0;

(2) combining a melt direct spinning online addition process with an FDY process, and preparing modified polyester FDY yarns from the modified polyester melt according to the combined process to obtain melt direct spinning online addition colored polyester fibers, wherein the melt direct spinning online addition process comprises the following steps: before the melt enters the spinning manifold, injecting the color master batch after drying, melting, filtering and metering, and after fully and uniformly mixing with the melt through a high-efficiency dynamic mixer, the color master batch and the melt jointly enter the spinning manifold, wherein the flow of the FDY process is as follows: metering, spinneret plate extruding, cooling, oiling, stretching, heat setting and winding, wherein the parameters of the FDY process are as follows: the spinning temperature is 295 ℃, the cooling temperature is 23 ℃, the network pressure is 0.30MPa, the one-roller speed is 2100m/min, the one-roller temperature is 75 ℃, the two-roller speed is 4000m/min, the two-roller temperature is 105 ℃, and the winding speed is 3850 m/min.

The filament number of the finally prepared melt direct spinning on-line additive colored polyester fiber is 3.0dtex, the breaking strength is 4.2cN/dtex, the CV value of the breaking strength is 4.6%, the elongation at break is 35%, the CV value of the elongation at break is 8.3%, the shrinkage in boiling water is 7.5%, the yarn levelness CV value is 1.5%, the oil content is 1.10 wt%, and the network degree is 22/m;

Example 7

(1) preparing modified polyester;

(1.1) preparation of 2, 5-di-tert-butyl-1, 6-hexanedicarboxylic acid: firstly, mixing tungstic acid and hydrogen peroxide, stirring for 11min at room temperature, then adding 2, 4-di-tert-butylcyclohexanol, reacting for 1h at the temperature of 80 ℃, then heating to 95 ℃ and reacting for 2.2h, wherein reactants are always in a reflux state in the reaction process, and finally cooling, crystallizing, washing and refining, wherein the molar ratio of the tungstic acid to the 2, 4-di-tert-butylcyclohexanol to the hydrogen peroxide is 1:35:150 at the beginning of the reaction;

(a) mixing KOH powder, 3-methyl-3-hydroxybutyne, 3-dimethyl-2-butanone and isopropyl ether according to a molar ratio of 1.2:1:1.2:3.0, reacting for 3 hours under an ice bath condition, and after the reaction is finished, cooling, crystallizing, centrifugally separating, washing, refining and drying to obtain octynediol;

(b) mixing octynediol, ethanol and a palladium catalyst according to the weight ratio of 3:10:0.02, reacting for 55min at the temperature of 42 ℃, continuously introducing hydrogen in the reaction process, and separating and purifying after the reaction is finished to obtain 2,5,6, 6-tetramethyl-2, 5-heptanediol, wherein the structural formula of the 2,5,6, 6-tetramethyl-2, 5-heptanediol is shown as a formula (I);

(1.3) esterification reaction;

preparing terephthalic acid, ethylene glycol, 2, 5-di-tert-butyl-1, 6-hexanedioic acid, 2-difluoro-1, 5-glutaric acid and 2,5,6, 6-tetramethyl-2, 5-heptanediol into slurry, adding ethylene glycol antimony, titanium dioxide and trimethyl phosphite, uniformly mixing, pressurizing in a nitrogen atmosphere to perform esterification reaction, wherein the pressurizing pressure is 0.2MPa, the esterification reaction temperature is 250 ℃, the end point of the esterification reaction is determined when the distilled amount of water in the esterification reaction reaches 92% of a theoretical value, the molar ratio of the terephthalic acid to the ethylene glycol is 1:1.2, 2, 5-di-tert-butyl-1, 6-hexanedioic acid, 2-difluoro-1, 5-glutaric acid and 2,5,6, 6-tetramethyl-2, 5-heptanediol, and the sum of the added amounts of the terephthalic acid is 4.5 mol%, the molar ratio of 2, 5-di-tert-butyl-1, 6-hexanedicarboxylic acid, 2-difluoro-1, 5-glutaric acid and 2,5,6, 6-tetramethyl-2, 5-heptanediol was 1.3:2:4, and the amounts of ethylene glycol antimony, titanium dioxide and trimethyl phosphite were 0.04 wt%, 0.22 wt% and 0.01 wt%, respectively, of the amount of terephthalic acid added;

(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 440Pa within 40min, controlling the reaction temperature to be 260 ℃ 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 274 ℃ and control the reaction time to be 50min, wherein the number average molecular weight of the prepared modified polyester is 29500 and the molecular weight distribution index is 2.1;

(2) combining a melt direct spinning online addition process with an FDY process, and preparing modified polyester FDY yarns from the modified polyester melt according to the combined process to obtain melt direct spinning online addition colored polyester fibers, wherein the melt direct spinning online addition process comprises the following steps: before the melt enters the spinning manifold, injecting the color master batch after drying, melting, filtering and metering, and after fully and uniformly mixing with the melt through a high-efficiency dynamic mixer, the color master batch and the melt jointly enter the spinning manifold, wherein the flow of the FDY process is as follows: metering, spinneret plate extruding, cooling, oiling, stretching, heat setting and winding, wherein the parameters of the FDY process are as follows: the spinning temperature is 288 ℃, the cooling temperature is 19 ℃, the network pressure is 0.27MPa, the one-roller speed is 2500m/min, the one-roller temperature is 75 ℃, the two-roller speed is 3600m/min, the two-roller temperature is 120 ℃, and the winding speed is 3920 m/min.

The filament number of the finally prepared melt direct spinning on-line additive colored polyester fiber is 2.6dtex, the breaking strength is 3.8cN/dtex, the CV value of the breaking strength is 5.0%, the elongation at break is 39%, the CV value of the elongation at break is 8.6%, the shrinkage in boiling water is 7.0%, the yarn levelness CV value is 1.44%, the oil content is 1.20 wt%, and the network degree is 20/m;

Claims

1. The preparation method of the melt direct spinning on-line addition colored polyester fiber is characterized by comprising the following steps: combining the melt direct spinning online addition process with the FDY process, and preparing modified polyester FDY yarns from the modified polyester melt according to the combined process to obtain melt direct spinning online addition colored polyester fibers;

the dibasic acid with tertiary butyl side group is 5-tertiary butyl-1, 3-phthalic acid, 2-tertiary butyl-1, 6-hexanedicarboxylic acid, 3-tertiary butyl-1, 6-hexanedicarboxylic acid or 2, 4-di-tertiary butyl-1, 6-hexanedicarboxylic acid;

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;

。

2. the preparation method of the melt direct spinning on-line additive colored polyester fiber is characterized in that the color master batch consists of 20-30 wt% of pigment and 70-80 wt% of polyester, the mass ratio of the color master batch to the modified polyester melt is 1-3: 97-99, and the color of the pigment is red, yellow, blue, green, purple or black;

the synthesis method of the 2-tert-butyl-1, 6-hexanedicarboxylic acid, the 3-tert-butyl-1, 6-hexanedicarboxylic acid and the 2, 4-di-tert-butyl-1, 6-hexanedicarboxylic acid comprises the following steps:

the raw material alcohols corresponding to the 2-tert-butyl-1, 6-hexanedicarboxylic acid, the 3-tert-butyl-1, 6-hexanedicarboxylic acid and the 2, 4-di-tert-butyl-1, 6-hexanedicarboxylic acid are respectively 2-tert-butylcyclohexanol, 4-tert-butylcyclohexanol and 2, 4-di-tert-butylcyclohexanol;

(1) mixing KOH powder, 3-methyl-3-hydroxybutyne, 3-dimethyl-2-butanone and isopropyl ether according to a molar ratio of 1-1.2: 1.2-1.3: 2.0-3.0, reacting for 2-4 hours under an ice bath condition, and after the reaction is finished, cooling, crystallizing, centrifugally separating, washing, refining and drying to obtain heptynediol;

(2) mixing heptynediol, ethanol and a palladium catalyst according to the weight ratio of 2-3: 10: 0.01-0.03, reacting at the temperature of 40-50 ℃ for 50-60 min, continuously introducing hydrogen during the reaction process, and separating and purifying after the reaction is finished to obtain 2,5,6, 6-tetramethyl-2, 5-heptanediol.

3. The method for preparing the melt direct spinning on-line additive colored polyester fiber according to claim 2, wherein the modified polyester is prepared by the following steps:

(1) performing esterification reaction;

(2) performing polycondensation reaction;

4. The method for preparing the melt direct spinning on-line additive colored polyester fiber according to claim 3, wherein the molar ratio of terephthalic acid to ethylene glycol is 1: 1.2-2.0, the sum of the addition amounts of the dibasic acid with the tertiary butyl side group, the fluorine-containing dibasic acid and the 2,5,6, 6-tetramethyl-2, 5-heptanediol is 3-5 mol% of the addition amount of terephthalic acid, the molar ratio of the dibasic acid with the tertiary butyl side group, the fluorine-containing dibasic acid and the 2,5,6, 6-tetramethyl-2, 5-heptanediol is 1-2: 2-4: 3-5, and the addition amounts of the catalyst, the delustering agent and the stabilizer are 0.03-0.05 wt%, 0.20-0.25 wt% and 0.01-0.05 wt% of the addition amount of terephthalic acid, respectively.

5. The method for preparing the melt direct spinning on-line additive colored polyester fiber according to claim 4, wherein the catalyst is antimony trioxide, ethylene glycol antimony or antimony acetate, the delustrant is titanium dioxide, and the stabilizer is triphenyl phosphate, trimethyl phosphate or trimethyl phosphite.

6. The method for preparing the melt direct spinning on-line additive colored polyester fiber according to claim 5, wherein the modified polyester has a number average molecular weight of 25000-30000 and a molecular weight distribution index of 1.8-2.2.

7. The method for preparing the melt direct spinning on-line additive colored polyester fiber according to claim 1, wherein the melt direct spinning on-line additive process comprises the following steps: before the melt enters the spinning manifold, injecting the color master batch after drying, melting, filtering and metering, and after fully and uniformly mixing the color master batch with the melt through a high-efficiency dynamic mixer, the color master batch and the melt jointly enter the spinning manifold;

8. The melt direct-spinning on-line additive colored polyester fiber prepared by the preparation method of the melt direct-spinning on-line additive colored polyester fiber according to any one of claims 1 to 7 is characterized in that: is modified polyester FDY yarn;

9. The melt direct spinning on-line additive colored polyester fiber according to claim 8, wherein the melt direct spinning on-line additive colored polyester fiber has a filament number of 1.0 to 3.0dtex, a breaking strength of not less than 3.8cN/dtex, a breaking strength CV value of not more than 5.0%, an elongation at break of 35 +/-4%, an elongation at break CV value of not more than 9.0%, a boiling water shrinkage of 7.0 +/-0.5%, a yarn dry CV value of not more than 1.5%, an oil content of 1.00 +/-0.20 wt%, and a network degree of 20 +/-4/m.

10. The melt direct spinning on-line additive colored polyester fiber as claimed in claim 8, wherein the intrinsic viscosity of the melt direct spinning on-line additive colored polyester fiber decreases by 15-20% after the melt direct spinning on-line additive colored polyester fiber is placed for 60 months at 25 ℃ and a relative humidity of 65%.