Moisture-absorption quick-dry light and thin knitted fabric and preparation method thereof

Abstract

The invention discloses a moisture-absorption quick-dry light and thin knitted fabric and a preparation method thereof, and relates to the technical field of knitted fabrics. The moisture-absorption quick-dry light and thin knitted fabric is formed by weaving yarns with high titanium dioxide content; the surface of the moisture-absorbing quick-dry light and thin knitted fabric is provided with a concave-convex structure, and each convex point part is formed by stacking 2-4 yarns; in the concave-convex structure, the distance between two transverse adjacent convex point parts is 300 to 3000 microns; and the distance between the longitudinal adjacent salient point parts is 300-3000 [mu] m. The yarn is of a core-sheath structure. The content of titanium dioxide in the yarn core part is 5%-15%; and the content of titanium dioxide in the sheath part of the yarn is 0.2-15%. The prepared knitted fabric has the moisture absorption and sweat releasing functions and can be kept free of sweat stain traces; the fabric can ensure that a wearer can still keep an elegant and natural appearance while enjoying comfortable wearing experience.

Description

Technical Field

[0001] The invention relates to the technical field of knitted fabrics, in particular to a moisture-absorbing, quick-drying, light and thin knitted fabric and a preparation method thereof. Background Art

[0002] As people's living standards improve, the demand for functional clothing continues to grow. Among them, summer knitted fabrics need to balance lightness, breathability and aesthetics. In hot seasons, fabrics need to effectively remove moisture and evaporate sweat quickly, and keep the wearer's appearance neat and elegant. Although summer knitted fabrics have improved comfort and breathability to a certain extent, they still fail to eliminate the traces of sweat on the fabric, affecting the overall aesthetics of the clothing. In the prior art, patent CN116121939A discloses a kind of hidden sweat knitted fabric and its weaving method, in which the surface is a waterproof layer and the inside is a water-absorbing layer, which can prevent sweat from penetrating into the surface, but is not conducive to perspiration; patent CN115398051A discloses a knitted fabric and its use, in which a yarn containing more than 8wt% of inorganic particles is introduced into the surface knitted fabric to achieve the effect of waterproof traces on the surface, but the surface of the fabric is too flat, and the effect of overall waterproof traces is limited.

[0003] In summary, it is particularly important to solve the above problems and prepare a knitted fabric that has both moisture absorption and perspiration-wicking functions and remains free of sweat stains. Summary of the invention

[0004] The object of the present invention is to provide a moisture-absorbing, quick-drying, lightweight knitted fabric and a preparation method thereof, so as to solve the problems raised in the above-mentioned background technology.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions: a moisture-absorbing quick-drying light and thin knitted fabric, wherein the moisture-absorbing quick-drying light and thin knitted fabric is woven from yarns with a high content of titanium dioxide; the surface of the moisture-absorbing quick-drying light and thin knitted fabric has a concave-convex structure, and the convex point is formed by stacking 2 to 4 yarns; In the concavo-convex structure, the spacing between two adjacent convex point locations in the transverse direction is 300-3000 μm; the spacing between two adjacent convex point locations in the longitudinal direction is 300-3000 μm.

[0006] More optimally, the yarn has a core-sheath structure; the titanium dioxide content of the yarn core is 5-15%, and the titanium dioxide content of the yarn warp is 0.2-15%; More optimally, the titanium dioxide content of the yarn core is 8-12%, and the titanium dioxide content of the yarn warp is 0.2-5%. In the optimized solution, titanium dioxide with a gradient content in the core warp layer is used, and other raw materials with different proportions are used in combination to effectively enhance the spinnability and moisture absorption and perspiration wicking properties.

[0007] More optimally, a method for preparing a moisture-absorbing, quick-drying, lightweight knitted fabric comprises the following steps: Step 1: (1) Weigh different proportions of polyester, polyamide, polyamide-modified polyester, and titanium dioxide as core raw materials and warp raw materials; (2) Place the core raw materials and warp raw materials in a two-component spinning machine containing a core-sheath spinning assembly for composite spinning; wherein the core-sheath ratio is 1:1, the spinning temperature of the core component is 260-290°C, and the spinning temperature of the warp component is 280-300°C; cool by annular air blowing, draw and wind to obtain chemical fiber; and stretch and false-twist the fiber to obtain yarn; Step 2: Use yarn to weave a grey fabric, and then perform surfactant pretreatment, dyeing, and post-finishing on the grey fabric to obtain a moisture-absorbing, quick-drying, and lightweight knitted fabric.

[0008] More optimally, during the weaving process of the grey fabric, when 4 routes are used as one weaving cycle, the second needles of the first route and the second route are formed by the accumulation of two yarns to form a convex point; When 8 routes are used as one knitting cycle, the second needles of the 1st, 2nd and 3rd routes pile up three yarns to form a convex point, or the second needles of the 1st, 2nd, 3rd and 4th routes pile up four yarns to form a convex point.

[0009] More optimally, the core material comprises the following components: by weight, 58-82 parts of polyester, 8-12 parts of polyamide, 5-15 parts of polyamide-modified polyester, and 5-15 parts of titanium dioxide; The warping raw material comprises the following components: by weight, 62-94.6 parts of polyester, 5-8 parts of polyamide, 0.2-15 parts of polyamide-modified polyester, and 0.2-15 parts of titanium dioxide.

[0010] More optimally, the preparation method of the polyamide-modified polyester comprises the following steps: (1) Add polyester to N-methylpyrrolidone and stir evenly, then add 1-ethyl-3-methylimidazolium chloride, glycerol and butene glycol in sequence, stir at 170-180°C for 12-20 hours, cool, add deionized water for precipitation, wash and dry to obtain branched PET oligomer; (2) Stir the branched PET oligomer, epichlorohydrin and benzyltriethylammonium chloride evenly, stir at 80-85°C for 2-4 hours under a nitrogen atmosphere, add 30-40 wt% sodium hydroxide solution, continue stirring for 1-2 hours, filter, wash and dry to obtain epoxidized PET oligomer; (3) Add epoxidized PET oligomer, low molecular weight polyamide, aminosilane coupling agent, amino antioxidant and formic acid into anhydrous ethanol in sequence, stir at 78-82° C. for 10-12 hours under nitrogen atmosphere, filter, wash and dry to obtain polyamide modified polyester.

[0011] More optimally, the raw materials of the polyamide-modified polyester include the following components: by weight, 50 parts of epoxidized PET oligomer, 15-20 parts of low molecular weight polyamide, 5-8 parts of aminosilane coupling agent, 3-5 parts of amino antioxidant, and 1-3 parts of formic acid; The raw materials of the branched PET oligomer include the following components: 200 parts of polyester, 1-2 parts of 1-ethyl-3-methylimidazolium chloride, 10-15 parts of glycerol, and 6-10 parts of butene glycol, by weight; The raw materials of the epoxidized PET oligomer include the following components: by weight, 100 parts of branched PET oligomer, 120-150 parts of epichlorohydrin, 2-3 parts of benzyltriethylammonium chloride, and 8-12 parts of sodium hydroxide.

[0012] More optimally, the average molecular weight of the low molecular weight polyamide is 700-800.

[0013] More optimally, the preparation method of the amino antioxidant comprises the following steps: adding 3,5-di-tert-butyl-4-hydroxybenzaldehyde and 1,8-octanediamine in a molar ratio of 1:1 to anhydrous ethanol in sequence, stirring and reacting at 60-65° C. for 2-3 hours under a nitrogen atmosphere, evaporating the solvent, purifying, and obtaining an amino antioxidant.

[0014] More optimally, during the cooling process of the annular air, the temperature of the annular air is 50-60°C, and the temperature of the yarn chamber is 25-30°C; during the drawing and winding process, the drawing speed is 500-600m / min, the drawing multiple is 2.5-3.5, and the winding is 1000-1500m / min; The surfactant pre-treatment treatment liquid comprises the following components: 0.8-1.2 g / L of a hydrophilic surfactant containing a thiol group, 0.005-0.008 g / L of an initiator, and the rest is deionized water; the treatment temperature is 90-98°C.

[0015] Compared with the prior art, the beneficial effects achieved by the present invention are: chemical fibers with a high titanium dioxide content are prepared through a specific process and formula, and the fibers are made into yarns for weaving to form a single-layer moisture-absorbing, quick-drying, and thin knitted fabric with a concave-convex structure; the single-layer knitted fabric has the properties of moisture absorption and perspiration removal without sweat stains.

[0016] In the scheme, the yarn is prepared from chemical fiber with high titanium dioxide content. The fiber is prepared using a core-sheath spinning assembly, which has a core-sheath structure and effectively absorbs moisture and perspiration. Among them, due to the introduction of high-content titanium dioxide, its reflection of light is utilized to effectively improve the anti-perspiration performance; and when the yarn is woven, 2 to 4 yarns are piled up to form convex points to form a surface concave-convex structure, which further expands the light scattering effect and synergistically improves the anti-perspiration performance; at the same time, this structure effectively improves the perspiration and breathability of the fabric.

[0017] In this scheme, polyamide is introduced into polyester as the main chemical fiber; polyester has high heat resistance and fastness resistance, but its hydrophilicity is not good, which is not conducive to moisture absorption and perspiration, nor is it conducive to subsequent dyeing; while polyamide has good hydrophilicity, which is conducive to moisture absorption and dyeing, so polyamide is used to optimize complementary properties. Another scheme introduces polyamide, which has better interface properties with titanium dioxide and can improve the dispersibility of titanium dioxide.

[0018] On the other hand, the introduction of high content of titanium dioxide in the fiber will cause spinning difficulties, dispersibility and compatibility, resulting in decreased mechanical properties, increased spinning friction, broken wires, low drape and other problems. Although polyamide has affinity with titanium dioxide, it has polarity differences with polyester; therefore, for the sake of spinnability, the above defects are effectively solved in the scheme by introducing polyamide-modified polyester. Among them, polyamide-modified polyester is prepared by first depolymerizing polyester and then epoxidizing it to obtain epoxidized PET oligomers; then, it is prepared by grafting low molecular weight polyamide, aminosilane coupling agent and amino antioxidant by the reaction of amino and epoxy groups; it contains polyester segments and polyamide segments and has excellent similar compatibility with the main material. At the same time, the grafting of amino antioxidants effectively enhances its high temperature stability and increases processability; and there is no need to introduce antioxidants later, which effectively inhibits the migration of small molecules during processing. At the same time, the introduced aminosilane coupling agent can effectively promote the dispersion of titanium dioxide, inhibit aggregation and improve processing performance.

[0019] Among them, the molecular weight of low molecular weight polyamide needs to be limited. Too high molecular weight will increase the molecular entanglement of polyamide-modified polyester and increase the spinning viscosity, which is not conducive to spinning.

[0020] Among them, butene glycol is introduced during the cracking process, so that its chain segment contains vinyl, which is beneficial to the subsequent grafting of thiol-containing surfactants, thereby improving moisture absorption and perspiration, and enhancing subsequent dyeing performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings: Figure 1 This is the weaving diagram of structure 1 of the grey cloth of Example 1; Figure 2 This is the weaving diagram of structure 2 of the grey cloth of Example 2; Figure 3 This is the weaving diagram of structure 3 of the grey cloth of Example 3. DETAILED DESCRIPTION

[0022] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] It should be noted that the raw materials involved in the present invention are purchased from manufacturers without any special restrictions and are exemplified as follows: In the following embodiments, parts are parts by mass; the polyamide is polyamide 56 oligomer; the polyester is PET-FD501; the average specification of titanium dioxide is 5nm; all are commercially purchased.

[0024] The preparation method of the yarn in Examples 1, 2, 3 and Comparative Example 1 is as follows: Step 1: (1) Add 200 parts of polyester to N-methylpyrrolidone and stir evenly, then add 1.5 parts of 1-ethyl-3-methylimidazolium chloride, 12 parts of glycerol and 8 parts of butene glycol in sequence, stir at 180°C for 18 hours, cool, add deionized water for precipitation, wash and dry to obtain a branched PET oligomer; (2) Stir 100 parts of branched PET oligomer, 129 parts of epichlorohydrin and 2.2 parts of benzyltriethylammonium chloride evenly, stir at 80°C for 2 hours under a nitrogen atmosphere, add 40 wt% sodium hydroxide solution (10 parts of sodium hydroxide), continue stirring for 2 hours, filter, wash and dry. (3) adding 3,5-di-tert-butyl-4-hydroxybenzaldehyde and 1,8-octanediamine in a molar ratio of 1:1 to anhydrous ethanol in sequence, stirring at 60°C for 2 hours under a nitrogen atmosphere, evaporating the solvent, purifying, and obtaining an amino antioxidant; (4) adding 50 parts of an epoxidized PET oligomer, 18 parts of a low molecular weight polyamide (300 low molecular weight polyamide, molecular weight 700-800, commercially available), 6 parts of an aminosilane coupling agent KH550, 4 parts of an amino antioxidant, and 2 parts of formic acid to anhydrous ethanol in sequence, stirring at 80°C for 12 hours under a nitrogen atmosphere, filtering, washing, and drying to obtain a polyamide-modified polyester; Step 2: (1) Weigh 70 parts of polyester, 10 parts of polyamide, 10 parts of polyamide-modified polyester, and 10 parts of titanium dioxide as core raw materials; weigh 88 parts of polyester, 6 parts of polyamide, 3 parts of polyamide-modified polyester, and 3 parts of titanium dioxide as warp raw materials; (2) place the core raw materials and the warp raw materials in a two-component spinning machine containing a core-sheath spinning assembly, with a core-sheath ratio of 1:1, and set the spinning temperature of the core component to 270°C and the spinning temperature of the warp component to 290°C for composite spinning; cool with annular air at a temperature of 55°C and a yarn chamber temperature of 30°C; draw and wind at a traction speed of 600m / min, a traction multiple of 3, and a winding rate of 1200m / min to obtain chemical fiber; and stretch and false-twist the fiber to obtain yarn.

[0025] Embodiment 1: A method for preparing a moisture-absorbing, quick-drying, lightweight knitted fabric comprises the following steps: Step 1: On a 32-needle single-sided circular knitting machine, the yarn is 75D / 48F-DTY (titanium dioxide content 13%), and the grey fabric is knitted with 4 passes as one knitting cycle; wherein, during the knitting process, the needles are arranged 1213, and the second needles of the first pass and the second pass pile up the two yarns and form a convex part on the surface of the fabric, such as Figure 1 The organization 1 is shown in the weaving diagram; Step 2: The grey cloth is sequentially subjected to surfactant pretreatment (phospholipid polyethylene glycol thiol 1g / L, initiator AIBN 0.005g / L, and the rest is deionized water; the treatment temperature is 90-98°C, and the treatment time is 1 hour), dyeing (disperse dye HL-R-01, dyeing temperature is 130°C, and dyeing time is 30 minutes), and post-finishing processing (10g / L water-based polyester resin LX710, 1g / L neutralizing acid TY-W206, and the rest is deionized water, two immersions and two rollings), and dried at 100°C to obtain a moisture-absorbing, quick-drying, and thin knitted fabric.

[0026] Embodiment 2: A method for preparing a moisture-absorbing, quick-drying, lightweight knitted fabric comprises the following steps: Step 1: On a 32-needle single-sided circular knitting machine, the yarn is 75D / 48F-DTY (titanium dioxide content 13%), and the grey fabric is knitted with 4 passes as one knitting cycle; wherein, during the knitting process, the needles are arranged 1213, and the second needles of the first, second and third passes pile up the three yarns and form a convex portion on the surface of the fabric, such as Figure 2 The organization 2 is shown in the weaving diagram; Step 2: The grey cloth is sequentially subjected to surfactant pretreatment (phospholipid polyethylene glycol thiol 1g / L, initiator AIBN 0.005g / L, and the rest is deionized water; the treatment temperature is 90-98°C, and the treatment time is 1 hour), dyeing (disperse dye HL-R-01, dyeing temperature is 130°C, and dyeing time is 30 minutes), and post-finishing processing (10g / L water-based polyester resin LX710, 1g / L neutralizing acid TY-W206, and the rest is deionized water, two immersions and two rollings), and dried at 100°C to obtain a moisture-absorbing, quick-drying, and thin knitted fabric.

[0027] Embodiment 3: A method for preparing a moisture-absorbing, quick-drying, lightweight knitted fabric comprises the following steps: Step 1: On a 32-needle single-sided circular knitting machine, the yarn is 75D / 48F-DTY (titanium dioxide content 13%), and the grey fabric is knitted with 4 passes as one knitting cycle; wherein, during the knitting process, the needles are arranged 1213, and the second needles of the 1st, 2nd, 3rd and 4th passes pile up the four yarns and form a convex part on the surface of the fabric, such as Figure 3 The organization 3 is shown in the weaving diagram; Step 2: The grey cloth is sequentially subjected to surfactant pretreatment (phospholipid polyethylene glycol thiol 1g / L, initiator AIBN 0.005g / L, and the rest is deionized water; the treatment temperature is 90-98°C, and the treatment time is 1 hour), dyeing (disperse dye HL-R-01, dyeing temperature is 130°C, and dyeing time is 30 minutes), and post-finishing processing (10g / L water-based polyester resin LX710, 1g / L neutralizing acid TY-W206, and the rest is deionized water, two immersions and two rollings), and dried at 100°C to obtain a moisture-absorbing, quick-drying, and thin knitted fabric.

[0028] Comparative Example 1: Based on Example 3, the second needles of the first, second, third and fourth routes are knitted with one yarn, and no convex portion is formed; the rest is the same as Example 3; Comparative Example 2: Based on Example 3, the components of the chemical fiber core of the yarn were adjusted, and the rest were the same as Example 3; the specific differences are as follows: In the process of yarn preparation, (1) 80 parts of polyester, 10 parts of polyamide, 5 parts of polyamide-modified polyester, and 5 parts of titanium dioxide are weighed as core raw materials; 88 parts of polyester, 6 parts of polyamide, 3 parts of polyamide-modified polyester, and 3 parts of titanium dioxide are weighed as warp raw materials; (2) the core raw materials and the warp raw materials are placed in a two-component spinning machine containing a core-sheath type spinning assembly, with a core-sheath ratio of 1:1, and the spinning temperature of the core component is set to 270°C and the spinning temperature of the warp component is set to 290°C for composite spinning; the yarn is cooled by annular blowing at a temperature of 55°C and a yarn chamber temperature of 30°C; the yarn is drawn and wound at a traction speed of 600m / min, a traction multiple of 3, and a winding rate of 1200m / min to obtain chemical fiber; and the yarn is stretched and false-twisted to obtain yarn.

[0029] Comparative Example 3: Based on Example 3, the preparation of the polyamide-modified polyester in the chemical fiber of the yarn was adjusted, and the rest was the same as Example 3; the specific differences are as follows: in the preparation process of the polyamide-modified polyester, the polyamide is a 200 low molecular weight polyamide with a molecular weight of 1000~1500; commercially available.

[0030] Comparative Example 4: Based on Example 3, the components of the chemical fiber of the yarn were adjusted; PP-g-MAH was used to replace the polyamide-modified polyester as a compatibilizer; the rest was the same as Example 3.

[0031] Experiment 1: The moisture-absorbing, quick-drying, and light knitted fabrics prepared by the implementation schemes in Examples 1 to 3 and Comparative Examples 1 to 4 were subjected to relevant performance tests. (1) Test method for sweat-free effect: Cut a 10 cm × 10 cm sample and place it at a temperature of 20 ± 2 ° C and a humidity of 65 ± 4% for 24 hours; drip 0.2 mL of deionized water 5 cm above the sample, wet it for 2 minutes, and then place it in a standard color matching light box and rate it according to the gray sample card for color change assessment in accordance with GB / T250-2008; (2) Cut a 10 cm × 10 cm sample and place it at a temperature of 20 ± 2 ° C and a humidity of 65 ± 4% for 24 hours; refer to GB / T 21655.1, drip 0.2 mL of deionized water 5 cm above the sample, and test the water droplet diffusion time; and test the evaporation rate; (3) Pay attention to the overall textile process and the number of broken ends per day; the obtained data are shown in the following table:

[0032] Conclusion: From the data in the above table, it can be seen that the thin knitted fabric prepared by the present application effectively enhances its anti-perspiration effect by introducing chemical fibers with high titanium dioxide content; at the same time, it also has beneficial moisture absorption and perspiration properties. And the breakage of high-content titanium dioxide yarn is effectively improved by specifically preparing polyester-modified polyurethane. Among them, in Comparative Example 1, no concave-convex structure is set, so that its related performance decreases; in Comparative Example 2, since the raw material components of the core warp are the same and the titanium dioxide content is reduced, the performance is greatly reduced; in Comparative Example 3, due to the increase in the molecular weight of polyamide in polyamide-modified polyester, the breakage increases; in Comparative Example 4, due to the use of PP-g-MAH to replace polyamide-modified polyester, the dispersibility of titanium dioxide decreases, which increases the breakage.

[0033] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

Claims

1. A moisture-absorbing, quick-drying, light and thin knitted fabric, characterized in that: The moisture-absorbing, quick-drying, light and thin knitted fabric is woven from yarns with a high content of titanium dioxide; the surface of the moisture-absorbing, quick-drying, light and thin knitted fabric has a concave-convex structure, and the convex points are formed by the accumulation of 2 to 4 yarns; In the concavo-convex structure, the spacing between two adjacent convex point locations in the transverse direction is 300-3000 μm; the spacing between two adjacent convex point locations in the longitudinal direction is 300-3000 μm.

2. The moisture-absorbing, quick-drying, light and thin knitted fabric according to claim 1, characterized in that: The yarn has a core-sheath structure; the titanium dioxide content of the yarn core is 5% to 15%; and the titanium dioxide content of the yarn sheath is 0.2 to 15%.

3. The method for preparing a moisture-absorbing, quick-drying, light and thin knitted fabric according to claim 1, characterized in that: The following steps are involved: Step 1: (1) Weigh different proportions of polyester, polyamide, polyamide-modified polyester, and titanium dioxide as core raw materials and warp raw materials; (2) Place the core raw materials and warp raw materials in a two-component spinning machine containing a core-sheath spinning assembly for composite spinning; wherein the core-sheath ratio is 1:1, the spinning temperature of the core component is 260-290°C, and the spinning temperature of the warp component is 280-300°C; cool by annular air blowing, draw and wind to obtain chemical fiber; and stretch and false-twist the fiber to obtain yarn; Step 2: Use yarn to weave a grey fabric, and then perform surfactant pretreatment, dyeing, and post-finishing on the grey fabric to obtain a moisture-absorbing, quick-drying, and lightweight knitted fabric.

4. The method for preparing a moisture-absorbing, quick-drying, light and thin knitted fabric according to claim 3, characterized in that: During the weaving process of the grey fabric, when 4 routes are used as one weaving cycle, the second needles of the first route and the second route are formed by stacking two yarns to form a convex point; When 8 routes are used as one knitting cycle, the second needles of the 1st, 2nd and 3rd routes pile up three yarns to form a convex point, or the second needles of the 1st, 2nd, 3rd and 4th routes pile up four yarns to form a convex point.

5. The method for preparing a moisture-absorbing, quick-drying, light and thin knitted fabric according to claim 3, characterized in that: The core material comprises the following components: by weight, 58-82 parts of polyester, 8-12 parts of polyamide, 5-15 parts of polyamide-modified polyester, and 5-15 parts of titanium dioxide; The warping raw material comprises the following components: by weight, 62-94.6 parts of polyester, 5-8 parts of polyamide, 0.2-15 parts of polyamide-modified polyester, and 0.2-15 parts of titanium dioxide.

6. The method for preparing a moisture-absorbing, quick-drying, light and thin knitted fabric according to claim 3, characterized in that: The preparation method of the polyamide-modified polyester comprises the following steps: (1) Add polyester to N-methylpyrrolidone and stir evenly, then add 1-ethyl-3-methylimidazolium chloride, glycerol and butene glycol in sequence, stir at 170-180°C for 12-20 hours, cool, add deionized water for precipitation, wash and dry to obtain branched PET oligomer; (2) Stir the branched PET oligomer, epichlorohydrin and benzyltriethylammonium chloride evenly, stir at 80-85°C for 2-4 hours under a nitrogen atmosphere, add 30-40 wt% sodium hydroxide solution, continue stirring for 1-2 hours, filter, wash and dry to obtain epoxidized PET oligomer; (3) Add epoxidized PET oligomer, low molecular weight polyamide, aminosilane coupling agent, amino antioxidant and formic acid into anhydrous ethanol in sequence, stir at 78-82° C. for 10-12 hours under nitrogen atmosphere, filter, wash and dry to obtain polyamide modified polyester.

7. The method for preparing a moisture-absorbing, quick-drying, light and thin knitted fabric according to claim 6, characterized in that: The raw materials of the polyamide-modified polyester include the following components: by weight, 50 parts of epoxidized PET oligomer, 15-20 parts of low molecular weight polyamide, 5-8 parts of aminosilane coupling agent, 3-5 parts of amino antioxidant, and 1-3 parts of formic acid; The raw materials of the branched PET oligomer include the following components: 200 parts of polyester, 1-2 parts of 1-ethyl-3-methylimidazolium chloride, 10-15 parts of glycerol, and 6-10 parts of butene glycol, by weight; The raw materials of the epoxidized PET oligomer include the following components: by weight, 100 parts of branched PET oligomer, 120-150 parts of epichlorohydrin, 2-3 parts of benzyltriethylammonium chloride, and 8-12 parts of sodium hydroxide.

8. The method for preparing a moisture-absorbing, quick-drying, light and thin knitted fabric according to claim 6, characterized in that: The average molecular weight of the low molecular weight polyamide is 700-800.

9. The method for preparing a moisture-absorbing, quick-drying, light and thin knitted fabric according to claim 6, characterized in that: The preparation method of the amino antioxidant comprises the following steps: adding 3,5-di-tert-butyl-4-hydroxybenzaldehyde and 1,8-octanediamine in a molar ratio of 1:1 to anhydrous ethanol in sequence, stirring and reacting at 60-65° C. for 2-3 hours under a nitrogen atmosphere, evaporating the solvent, purifying, and obtaining an amino antioxidant.

10. The method for preparing a moisture-absorbing, quick-drying, light and thin knitted fabric according to claim 3, characterized in that: During the cooling process of the annular air, the temperature of the annular air is 50-60°C and the temperature of the yarn chamber is 25-30°C; during the drawing and winding process, the drawing speed is 500-600m / min, the drawing multiple is 2.5-3.5, and the winding rate is 1000-1500m / min; The surfactant pre-treatment treatment liquid comprises the following components: 0.8-1.2 g / L of a carboxyl-containing hydrophilic surfactant, 0.005-0.008 g / L of an initiator, and the rest is deionized water; the treatment temperature is 90-98°C.

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