Polyester fiber and production method and application thereof

Abstract

The invention relates to a polyester fiber and a production method and application thereof. The production method of the polyester fiber comprises the following steps: S1, mixing terephthalic acid, adipic acid, ethylene glycol, 1, 2-propylene glycol and tetrahydrophthalic acid diglycidyl ester to obtain a reactant, pulping, mixing with a first catalyst, and reacting in a protective gas atmosphere; s2, separating an organic phase and a water phase in an esterification reaction product, adding polybutylene terephthalate, a second catalyst and a stabilizer into the organic phase, reacting in a protective gas atmosphere, casting strips, and dicing to obtain polyester chips; and S3, drying the polyester chips, and then carrying out melt spinning to obtain the polyester fiber. Tetrahydrophthalic acid diglycidyl ester is added in the polyester synthesis process, the tetrahydrophthalic acid diglycidyl ester can react with carboxyl in carboxylic acid in a system to generate secondary hydroxyl, the secondary hydroxyl and the carboxyl continue to react to generate a branched chain, and in other words, by introducing the branched chain, the intermolecular acting force is reduced, and the melting point is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of textiles, and particularly relates to a polyester fiber, a production method thereof, and an application thereof. Background Art

[0002] Polyester fiber, commonly known as "polyester", is a widely used synthetic fiber, which refers to a general term for fibers made from polyesters obtained by polycondensation of dihydric alcohols and aromatic dicarboxylic acids or their esters. Polyester fiber has the advantages of a neat appearance, high strength, good dimensional stability, good thermal stability, and chemical corrosion resistance, and is widely used in making various textile products such as clothing, bedding, and interior decoration products.

[0003] Non-woven fabric is a new field in the textile industry. Low-melting-point polyester fiber is an important raw material for non-woven fabrics. After heating and melting, the low-melting-point polyester fiber plays a role in bonding and solidifying, that is, a physical bonding effect. Since no chemical binder is used, pollution can be reduced and costs can be lowered. Moreover, the non-woven fabric made of low-melting-point polyester fiber can not only maintain the inherent network structure of the non-woven fabric but also be more firm than the needle-punched non-woven fabric. Low-melting-point polyester fiber has also been increasingly valued in the field of fiber composites. The composite material made with low-melting-point polyester fiber as the matrix has good processing fluidity, good mixing uniformity with reinforcing fibers, and the toughness and strength of the product are both improved.

[0004] In related technologies, usually, isophthalic acid and other modified monomers are added to reduce the regularity of the polymer macromolecular chain, thereby reducing the melting point to prepare low-melting-point polyester fiber. However, when producing low-melting-point polyester fiber in this way, there are defects such as the copolyester being difficult to crystallize, poor stability in subsequent processing and forming, and the fiber obtained having a hard hand feeling, and the melting point of the polyester fiber needs to be further reduced. Summary of the Invention

[0005] In view of this, the present invention provides a polyester fiber, a production method thereof, and an application thereof to solve the above-mentioned defects such as the copolyester being difficult to crystallize, poor stability in subsequent processing and forming, and the fiber obtained having a hard hand feeling, and further reduce the melting point of the polyester fiber.

[0006] To achieve the above solution, the technical solution of the present invention is as follows:

[0007] In the first aspect, the present application provides a production method of a polyester fiber, including the following steps:

[0008] S1. Mix terephthalic acid, adipic acid, ethylene glycol, 1,2-propanediol, and diglycidyl tetrahydrophthalate to obtain a reactant. After beating, mix it with a first catalyst and react in a protective gas atmosphere;

[0009] S2. Separate the organic phase and the aqueous phase from the esterification reaction product, add polybutylene terephthalate, a second catalyst, and a stabilizer to the organic phase, and carry out a reaction, casting, and pelletizing in a protective gas atmosphere to obtain polyester chips.

[0010] S3. Dry the polyester chips, and then carry out melt spinning to obtain the polyester fiber.

[0011] In this application, by adding diglycidyl tetrahydrophthalate during the polyester synthesis process, secondary hydroxyl groups can be generated through the reaction of diglycidyl tetrahydrophthalate with carboxyl groups in carboxylic acids in the system. The secondary hydroxyl groups further react with carboxyl groups to form branched chains, that is, by introducing branches into the polyester molecular chain, the intermolecular force of the polyester is reduced, and the melting point of the polyester fiber is lowered. By introducing the modified monomer adipic acid (AA) through copolymerization during the polyester synthesis process, the regularity of the polyester macromolecular chain can be reduced, the melting point of the polyester can be lowered, and the crystallization performance and processing stability of the polyester fiber can be improved. By introducing the modified monomer 1,2-propanediol (α-PG) through copolymerization during the polyester synthesis process, the flexibility of the polyester macromolecular chain can be improved, the melting point of the polyester can be lowered, and the crystallization performance and processing stability of the polyester fiber can be improved, and the hand feeling of the polyester fiber can be improved. By blending polyethylene terephthalate (abbreviation PET) and polybutylene terephthalate (abbreviation PBT), block copolymers can be generated through transesterification reactions, affecting the crystallization integrity of polyethylene terephthalate (abbreviation PET), and further lowering the melting point of the polyester fiber.

[0012] Optionally, in step S1, the molar ratio of terephthalic acid, adipic acid, ethylene glycol, 1,2-propanediol, and diglycidyl tetrahydrophthalate is 0.4 - 0.6: 0.3 - 0.5: 1 - 1.5: 0.1 - 0.3: 0.02 - 0.03, preferably 0.4 - 0.6: 0.35 - 0.5: 1.1 - 1.5: 0.15 - 0.3: 0.025 - 0.03.

[0013] Optionally, in step S1, the protective gas is selected from at least one of nitrogen, helium, and argon.

[0014] Optionally, in step S1, the temperature of the reaction is 210 - 230 °C, preferably 215 - 230 °C; the pressure of the reaction is 0.1 - 0.3 MPa, preferably 0.12 - 0.3 MPa.

[0015] Optionally, in step S1, the first catalyst includes titanate and acetylacetone catalysts.

[0016] Optionally, in step S1, the molar ratio of the first catalyst to the reactant is 0.06 - 0.08:100, preferably 0.07 - 0.08:100.

[0017] Optionally, in step S1, the titanate is selected from tetra-isopropyl titanate, tetra-butyl titanate or a combination thereof.

[0018] Optionally, in step S1, the acetylacetone catalyst is selected from aluminum acetylacetonate, zinc acetylacetonate or a combination thereof.

[0019] Optionally, in step S1, the molar ratio of the titanate to the acetylacetone is 0.8 - 1.0:0.8 - 1.0, preferably 0.9 - 1.0:0.9 - 1.0.

[0020] Optionally, in step S1, the speed of pulping is 35 - 50 r / min, preferably 40 - 50 r / min; the duration of pulping is 45 - 75 min, preferably 50 - 75 min.

[0021] Optionally, in step S1, the reactant further includes isophthalic acid.

[0022] Optionally, in step S1, the molar ratio of the isophthalic acid to the terephthalic acid is 0.04 - 0.08:0.4 - 0.6, preferably 0.05 - 0.08:0.4 - 0.6.

[0023] In this application, by adding isophthalic acid during the polyester synthesis process, meta components can be introduced into the polyester polymer chain. In the meta-segment part, the conformation of the polyester polymer chain tends to form a coiled coil shape, which destroys the orderliness of the polyester polymer chain, reduces the regularity of the polyester polymer chain, reduces the crystallinity of the polyester, and further reduces the melting point of the polyester fiber.

[0024] Optionally, in step S2, the second catalyst is selected from zinc acetate (ZnAc 2 )

[0025] In this application, during the blending process of polyethylene terephthalate (abbreviated as PET) and polybutylene terephthalate (abbreviated as PBT), introducing zinc acetate (ZnAc 2 ) catalyst can promote the transesterification reaction, improve the blending efficiency, and ensure the quality stability of the low-melting-point polyester chips.

[0026] Optionally, in step S2, the molar ratio of the second catalyst to the terephthalic acid is 0.06 - 0.15:100, preferably 0.08 - 0.15:100.

[0027] Optionally, in step S2, the stabilizer is selected from at least one of triethyl phosphate, trimethyl phosphate, and triphenyl phosphate.

[0028] Optionally, in step S2, the molar ratio of the stabilizer to the terephthalic acid is 0.01 - 0.03:100, preferably 0.02 - 0.03:100.

[0029] Optionally, in step S2, the protective gas is selected from at least one of nitrogen, helium, and argon.

[0030] Optionally, in step S2, the temperature of the reaction is 160 - 180°C, preferably 165 - 180°C.

[0031] Optionally, in step S3, the temperature of the drying is 60 - 65°C, preferably 62 - 65°C.

[0032] Optionally, in step S3, during the drying process, the vacuum degree is 110 - 130 Pa, preferably 115 - 130 Pa.

[0033] Optionally, in step S3, the duration of the drying is 60 - 72 h, preferably 64 - 72 h.

[0034] Optionally, in step S3, the temperature of the melt spinning is 160 - 180°C, preferably 165 - 180°C.

[0035] In a second aspect, the present application also provides a polyester fiber prepared by the method as described above.

[0036] In a third aspect, the present application also provides the application of the polyester fiber prepared by the method as described above in core - shell products.

[0037] In the present application, core - shell products may include, for example, core - shell flocs. If the above - mentioned polyester fiber is used in core - shell flocs, the dosage of the above - mentioned polyester fiber can be 15% - 30%, preferably 20% - 30%. Exemplarily, to improve the environmental protection of the product, reduce the emission of harmful substances, and improve the recyclability and reusability of the product, the above - mentioned polyester fiber can be used in combination with fibers such as ordinary polyester fibers, cellulose fibers, polylactic acid fibers, and soybean fibers.

[0038] Since the melting point of the polyester fiber of the present application is much lower than that of conventional polyester fibers, after heating, the polyester fiber can be melted and used as an adhesive to wrap or bond other fibers. After cooling, a three-dimensional network structure is formed, which can avoid environmental problems such as formaldehyde residue caused by using chemical adhesives in the traditional technology; since the polyester fibers are evenly dispersed and the distribution of bonding points is controllable, hard lumps can be reduced. Therefore, using this polyester fiber in the core quilt flake product can ensure the flatness of the flake; the three-dimensional network structure formed after melting wraps fibers such as cotton fibers that are prone to sticking hair inside, and can also play an anti-pilling effect.

[0039] By using the above polyester fiber in the core quilt products, the present application can meet the needs of different consumers. The manufactured core quilt products not only have excellent heat preservation performance, but also have good air permeability and comfort. At the same time, by reducing the melting point of the polyester, the present application optimizes the production process, reduces energy consumption and production costs, and promotes green consumption and sustainable development. Specific embodiments

[0040] The following further illustrates the present invention through specific specific examples. It should be noted that the specific material ratios, process conditions and results described in the embodiments of the present invention are only used to illustrate the present invention, and cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit and essence of the present invention should be covered by the protection scope of the present invention.

[0041] An embodiment of the present application provides a production method of polyester fiber, including the following steps:

[0042] S1. Mix terephthalic acid, adipic acid, ethylene glycol, 1,2-propanediol and diglycidyl tetrahydrophthalate in a molar ratio of 0.4 - 0.6: 0.3 - 0.5: 1 - 1.5: 0.1 - 0.3: 0.02 - 0.03 to obtain a reactant, beat the reactant at 35 - 50 r / min for 45 - 75 min, and then mix it with a first catalyst, and carry out the reaction in a protective gas atmosphere. The reaction temperature is 210 - 230 °C, and the reaction pressure is 0.1 - 0.3 MPa. The first catalyst includes titanate and acetylacetone catalysts. The molar ratio of the first catalyst to the reactant is 0.06 - 0.08: 100, and the molar ratio of titanate to acetylacetone is 0.8 - 1.0: 0.8 - 1.0. The titanate is selected from tetra-isopropyl titanate, tetra-butyl titanate or a combination of the two, and the acetylacetone catalyst is selected from aluminum acetylacetonate, zinc acetylacetonate or a combination of the two;

[0043] S2. Separate the organic phase and the aqueous phase from the esterification reaction product, add polybutylene terephthalate, zinc acetate and a stabilizer to the organic phase. The molar ratio of zinc acetate to terephthalic acid is 0.06 - 0.15:100, and the molar ratio of the stabilizer to terephthalic acid is 0.01 - 0.03:100. The stabilizer is selected from at least one of triethyl phosphate, trimethyl phosphate and triphenyl phosphate;

[0044] Carry out the reaction, casting and pelletizing in a protective gas atmosphere to obtain polyester chips. The reaction temperature is 160 - 180 °C;

[0045] S3. Dry the polyester chips at a temperature of 60 - 65 °C and a vacuum degree of 110 - 130 Pa for 60 - 72 h, and then carry out melt spinning at a temperature of 160 - 180 °C to obtain polyester fibers.

[0046] In another embodiment of the present application, in step S1, the reactants further include isophthalic acid, and the molar ratio of isophthalic acid to the terephthalic acid is 0.04 - 0.08:0.4 - 0.6.

[0047] Another embodiment of the present application also provides a polyester fiber prepared by the method as described above.

[0048] Another embodiment of the present application also provides the application of the polyester fiber prepared by the method as described above in core-shell products.

[0049] The following specifically illustrates the present invention through exemplified embodiments. It should be understood that the following embodiments are only used to specifically illustrate the present invention and cannot be construed as limiting the protection scope of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the above content of the present invention all fall within the protection scope of the present invention. The specific process parameters and the like in the following examples are also only an example within a suitable range, that is, those skilled in the art can make selections within a suitable range through the description herein, rather than being limited to the specific values in the following examples.

[0050] Example 1

[0051] A production method of polyester fibers, the specific steps are as follows:

[0052] S1. Mix terephthalic acid, adipic acid, ethylene glycol, 1,2 - propanediol and diglycidyl tetrahydrophthalate in a molar ratio of 0.4:0.5:1:0.3:0.03 to obtain a reactant;

[0053] Pulp at 35 r / min for 75 min, and then mix with a first catalyst (composed of titanium tetraisopropoxide and aluminum acetylacetonate catalysts in a molar ratio of 0.8:1.0). The molar ratio of the first catalyst to the reactant is 0.08:100;

[0054] Subsequently, the reaction is carried out in nitrogen. The reaction temperature is 210 °C and the reaction pressure is 0.3 MPa.

[0055] S2. Separate the organic phase and the aqueous phase in the esterification reaction product. Add polybutylene terephthalate, zinc acetate, and trimethyl phosphate to the organic phase. The molar ratio of zinc acetate to terephthalic acid is 0.15:100, and the molar ratio of trimethyl phosphate to terephthalic acid is 0.01:100.

[0056] Carry out the reaction, casting, and pelletizing in nitrogen to obtain polyester chips. The reaction temperature is 160 °C.

[0057] S3. Dry the polyester chips at a temperature of 65 °C and a vacuum of 110 Pa for 60 h, and then carry out melt spinning at a temperature of 180 °C to obtain polyester fibers.

[0058] Example 2

[0059] A method for producing polyester fibers, the specific steps are as follows:

[0060] S1. Mix terephthalic acid, adipic acid, ethylene glycol, 1,2-propanediol, and diglycidyl tetrahydrophthalate according to a molar ratio of 0.6:0.3:1.5:0.1:0.02 to obtain a reactant.

[0061] Beat the mixture at 50 r / min for 75 min, and then mix it with a first catalyst (composed of tetrabutyl titanate and zinc acetylacetonate in a molar ratio of 1.0:0.8). The molar ratio of the first catalyst to the reactant is 0.06:100.

[0062] Subsequently, the reaction is carried out in nitrogen. The reaction temperature is 230 °C and the reaction pressure is 0.1 MPa.

[0063] S2. Separate the organic phase and the aqueous phase in the esterification reaction product. Add polybutylene terephthalate, zinc acetate, and triethyl phosphate to the organic phase. The molar ratio of zinc acetate to terephthalic acid is 0.06:100, and the molar ratio of triethyl phosphate to terephthalic acid is 0.03:100.

[0064] Carry out the reaction, casting, and pelletizing in nitrogen to obtain polyester chips. The reaction temperature is 180 °C.

[0065] S3. Dry the polyester chips at a temperature of 60 °C and a vacuum of 130 Pa for 72 h, and then carry out melt spinning at a temperature of 160 - °C to obtain polyester fibers.

[0066] Example 3

[0067] A production method of polyester fiber, the specific steps are as follows:

[0068] S1. Mix terephthalic acid, adipic acid, ethylene glycol, 1,2 - propanediol and diglycidyl tetrahydrophthalate in a molar ratio of 0.5:0.4:1.2:0.2:0.025 to obtain a reactant;

[0069] Pulverize at 45 r / min for 60 min, and then mix with a first catalyst (composed of tetrabutyl titanate and aluminum acetylacetonate in a molar ratio of 0.9:0.9), and the molar ratio of the first catalyst to the reactant is 0.07:100;

[0070] Subsequently, react in nitrogen, the reaction temperature is 220 °C, and the reaction pressure is 0.2 MPa;

[0071] S2. Separate the organic phase and the aqueous phase in the esterification reaction product, add polybutylene terephthalate, zinc acetate and triphenyl phosphate to the organic phase, the molar ratio of zinc acetate to terephthalic acid is 0.1:100, and the molar ratio of triphenyl phosphate to terephthalic acid is 0.02:100;

[0072] React, cast and pelletize in nitrogen to obtain polyester chips, and the reaction temperature is 170 °C;

[0073] S3. Dry the polyester chips at a temperature of 62 °C and a vacuum degree of 120 Pa for 65 h, and then carry out melt spinning at a temperature of 170 °C to obtain polyester fiber.

[0074] Example 4

[0075] Produce polyester fiber in the same manner as in Example 3 except for the following conditions:

[0076] S1. Mix terephthalic acid, isophthalic acid, adipic acid, ethylene glycol, 1,2 - propanediol and diglycidyl tetrahydrophthalate in a molar ratio of 0.5:0.04:0.4:1.2:0.2:0.025 to obtain a reactant;

[0077] Pulverize at 45 r / min for 60 min, and then mix with a first catalyst (composed of tetrabutyl titanate and aluminum acetylacetonate in a molar ratio of 0.9:0.9), and the molar ratio of the first catalyst to the reactant is 0.07:100;

[0078] Subsequently, react in nitrogen, the reaction temperature is 220 °C, and the reaction pressure is 0.2 MPa.

[0079] That is, the difference between this example and Example 3 is that in step S1, the reactant also includes isophthalic acid, and the molar ratio of isophthalic acid to terephthalic acid is 0.04:0.4.

[0080] Example 4

[0081] The polyester fiber was produced in the same manner as in Example 3, except for the following conditions:

[0082] S1. Mix terephthalic acid, isophthalic acid, adipic acid, ethylene glycol, 1,2 - propanediol, and diglycidyl tetrahydrophthalate in a molar ratio of 0.5:0.08:0.4:1.2:0.2:0.025 to obtain a reactant;

[0083] Beating was carried out for 60 min at 45 r / min, and then it was mixed with the first catalyst (composed of tetrabutyl titanate and aluminum acetylacetonate in a molar ratio of 0.9:0.9), and the molar ratio of the first catalyst to the reactant was 0.07:100;

[0084] Subsequently, the reaction was carried out in nitrogen, the reaction temperature was 220 °C, and the reaction pressure was 0.2 MPa.

[0085] That is, the difference between this example and Example 3 is that in step S1, the reactant also includes isophthalic acid, and the molar ratio of isophthalic acid to terephthalic acid is 0.08:0.4.

[0086] Comparative Example 1

[0087] The polyester fiber was produced in the same manner as in Example 3, except for the following conditions:

[0088] S1. Mix terephthalic acid, adipic acid, ethylene glycol, and 1,2 - propanediol in a molar ratio of 0.5:0.4:1.2:0.2 to obtain a reactant;

[0089] Beating was carried out for 60 min at 45 r / min, and then it was mixed with the first catalyst (composed of tetrabutyl titanate and aluminum acetylacetonate in a molar ratio of 0.9:0.9), and the molar ratio of the first catalyst to the reactant was 0.07:100;

[0090] Subsequently, the reaction was carried out in nitrogen, the reaction temperature was 220 °C, and the reaction pressure was 0.2 MPa.

[0091] That is, the difference between this comparative example and Example 3 is that in step S1, the reactant does not include diglycidyl tetrahydrophthalate.

[0092] Test

[0093] The melting points of the polyester fibers prepared in Examples 1 - 5 and Comparative Example 1 were tested by differential scanning calorimetry, and the results are shown in Table 1.

[0094] Table 1 Test Results

[0095] Group Melting point, °C Example 1 142 Example 2 151 Example 3 146 Example 4 122 Example 5 118 Comparative Example 1 171

[0096] As shown in Table 1, the melting point of the polyester fiber of Examples 1-3 is less than 155°C. The results show that in the present application, the introduction of the modified monomer adipic acid (AA) in the polyester synthesis process through copolymerization can reduce the regularity of the polyester polymer chain, reduce the melting point of the polyester, and improve the crystallization performance and processing stability of the polyester fiber; the introduction of the modified monomer 1,2-propylene glycol (α-PG) in the polyester synthesis process through copolymerization can improve the flexibility of the polyester polymer chain, reduce the melting point of the polyester, and improve the crystallization performance and processing stability of the polyester fiber, and improve the feel of the polyester fiber; by blending polyethylene terephthalate (PET) and polybutylene terephthalate (PBT), a block copolymer can be generated through an ester exchange reaction, which affects the crystallization integrity of polyethylene terephthalate (PET), thereby further reducing the melting point of the polyester fiber.

[0097] As can be seen from Table 1, the melting point of the polyester fiber of Example 3 is significantly reduced compared with Comparative Example 1. This result shows that in the present application, by adding diglycidyl tetrahydrophthalate during the synthesis of polyester, diglycidyl tetrahydrophthalate can react with the carboxyl group in the carboxylic acid in the system to generate secondary hydroxyl groups, and the secondary hydroxyl groups further react with the carboxyl groups to generate branched chains, that is, by introducing branched chains into the polyester molecular chain, the intermolecular forces of the polyester are reduced, and the melting point of the polyester fiber is reduced.

[0098] As can be seen from Table 1, the melting points of the polyester fibers of Examples 4 and 5 are significantly reduced compared with Example 3. The results show that in the present application, by adding isophthalic acid during the polyester synthesis process, the meta component can be introduced into the polyester polymer chain, and the conformation of the polyester polymer chain in the meta segment tends to form a curled coil morphology, which destroys the orderliness of the polyester polymer chain, reduces the regularity of the polyester polymer chain, reduces the crystallinity of the polyester, and further reduces the melting point of the polyester fiber.

[0099] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A method for producing polyester fiber, characterized in that: The following steps are involved: S1. Mix terephthalic acid, adipic acid, ethylene glycol, 1,2-propylene glycol and diglycidyl tetrahydrophthalate to obtain a reactant, mix it with a first catalyst after pulping, and react in a protective gas atmosphere; S2. Separating the organic phase and the aqueous phase of the esterification reaction product, adding polybutylene terephthalate, a second catalyst and a stabilizer to the organic phase, reacting in a protective gas atmosphere, casting, and pelletizing to obtain polyester chips; S3. Drying the polyester chips, and then melt spinning to obtain the polyester fibers.

2. The method for producing polyester fiber according to claim 1, characterized in that: In step S1, the molar ratio of the terephthalic acid, the adipic acid, the ethylene glycol, the 1,2-propylene glycol and the diglycidyl tetrahydrophthalate is 0.4-0.6: 0.3-0.5: 1-1.5: 0.1-0.3: 0.02-0.03; And / or, in step S1, the reaction temperature is 210-230°C, and the reaction pressure is 0.1-0.3 MPa.

3. The method for producing polyester fiber according to claim 1, characterized in that: In step S1, the first catalyst includes titanate and acetylacetone catalyst; And / or, in step S1, the molar ratio of the first catalyst to the reactant is 0.06-0.08:

100.

4. The method for producing polyester fiber according to claim 3, characterized in that: In step S1, the titanate is selected from tetraisopropyl titanate, tetrabutyl titanate or a combination thereof; And / or, in step S1, the acetylacetone catalyst is selected from aluminum acetylacetonate, zinc acetylacetonate or a combination thereof; And / or, in step S1, the molar ratio of the titanate to the acetylacetone is 0.8-1.0:0.8-1.0; And / or, in step S1, the beating speed is 35-50 r / min, and the beating time is 45-75 min.

5. The method for producing polyester fiber according to claim 1, characterized in that: In step S1, the reactants also include isophthalic acid.

6. The method for producing polyester fiber according to claim 5, characterized in that: In step S1, the molar ratio of the isophthalic acid to the terephthalic acid is 0.04-0.08:0.4-0.

6.

7. The method for producing polyester fiber according to claim 1, characterized in that: In step S2, the second catalyst is selected from zinc acetate; and / or, in step S2, the molar ratio of the second catalyst to the terephthalic acid is 0.06-0.15:100; And / or, in step S2, the stabilizer is selected from at least one of triethyl phosphate, trimethyl phosphate and triphenyl phosphate; and / or, in step S2, the molar ratio of the stabilizer to the terephthalic acid is 0.01-0.03:100; And / or, in step S2, the reaction temperature is 160-180°C.

8. The method for producing polyester fiber according to claim 1, characterized in that: In step S3, the drying temperature is 60-65°C; And / or, in step S3, during the drying process, the vacuum degree is 110-130Pa; And / or, in step S3, the drying time is 60-72 hours; And / or, in step S3, the temperature of the melt spinning is 160-180°C.

9. A polyester fiber obtained according to the method according to any one of claims 1 to 8.

10. Use of the polyester fiber prepared by the method according to any one of claims 1 to 8 in core quilt products.