Moisture-absorbing heating polyester fiber and preparation method thereof

Abstract

The invention belongs to the technical field of textile, and particularly discloses a moisture-absorbing and heating polyester fiber and a preparation method thereof.The preparation method comprises the steps that 1, modified polyester master batch is prepared, specifically, an inorganic layered silicate nanometer material, inorganic mineral filler, a quaternary ammonium salt organic compound and polyester are subjected to shear blending and extrusion granulation in a molten state, and the modified polyester master batch is prepared; and (2) preparing fibers, namely preparing polyester fibers with a sea-island structure by taking polyester master batches and the modified polyester master batches as island phases and alkali-soluble polyester as a sea phase, and dissolving the sea phase to obtain the moisture-absorbing and heat-generating polyester fibers. The moisture-absorbing and heat-generating performance of the fiber is improved through moisture-absorbing and heat-generating modification of polyester, combination with the superfine form of the fiber and exertion of a synergistic effect, and the fiber is good in mechanical property, simple in preparation process and low in cost.

Description

Technical Field

[0001] The present invention relates to the technical field of textiles, specifically to the technical field of functional fibers, and particularly to a moisture-absorbing and heat-generating polyester fiber and a preparation method thereof. Background Art

[0002] Due to its excellent mechanical properties, chemical corrosion resistance and easy processability, polyester fiber is widely used in the fields of textiles, clothing, home textiles, etc. However, ordinary polyester fiber has poor moisture absorption and poor wearing comfort, and it is difficult to provide a warming effect especially in cold environments.

[0003] Moisture-absorbing and heat-generating fiber is a new type of functional fiber. It is estimated that the human skin evaporates about 600 mL of latent sweat that is not perceived by the human body every day, which provides a stable energy source for the moisture-absorbing and heat-generating fiber. The moisture-absorbing and heat-generating fiber can absorb the moisture emitted by the human body and convert it into heat energy, so as to achieve the warming effect.

[0004] Currently, moisture-absorbing and heat-generating fibers mainly introduce hydrophilic groups on the fiber surface through chemical or physical methods to improve the moisture absorption of the fiber; or add moisture-absorbing and heat-generating materials such as ceramic powder and carbon black during the spinning process to achieve this. However, the fiber surface modification method has a complex process, high cost, and the modification effect is difficult to last. The added functional materials will also affect the mechanical properties and spinnability of the fiber due to poor compatibility with the polymer matrix, and the heat-generating effect is limited. Summary of the Invention

[0005] In view of the above-mentioned disadvantages of the prior art, the purpose of the present invention is to provide a moisture-absorbing and heat-generating polyester fiber and a preparation method thereof. Through the moisture-absorbing and heat-generating modification of polyester and combined with the ultrafine morphology of the fiber, the synergistic effect is exerted to improve the moisture-absorbing and heat-generating performance of the fiber.

[0006] To achieve the above purpose and other related purposes, the present invention provides a preparation method of a moisture-absorbing and heat-generating polyester fiber, including the following steps:

[0007] (1) Preparation of modified polyester masterbatch:

[0008] An inorganic layered silicate nanomaterial, an inorganic mineral filler, a quaternary ammonium salt organic compound and polyester are subjected to shear blending in a molten state, and then extruded and pelletized to prepare a modified polyester masterbatch;

[0009] (2) Preparation of fiber:

[0010] Using the polyester masterbatch and the modified polyester masterbatch as the island phase, and an alkali-soluble polyester as the sea phase, a polyester fiber with a sea-island structure is made, and then the sea phase is dissolved to obtain the moisture-absorbing and heat-generating polyester fiber.

[0011] Further, the inorganic layered silicate nanomaterial is selected from at least one of montmorillonite, sodium-based montmorillonite, calcium-based montmorillonite, kaolinite, vermiculite or mica.

[0012] Further, the inorganic mineral filler is selected from at least one of silica, titanium dioxide, talcum powder or calcium carbonate.

[0013] Further, the quaternary ammonium salt organic compound has the following structure: CH 3 (CH 2 )nNH 3 + , CH 3 (CH 2 )nNH 2 + R 1 , CH 3 (CH 2 )nNH + R 1 R 2 , CH 3 (CH 2 )nN + R 1 R 2 R 3 , wherein 1 ≤ n ≤ 18, and R 1 , R 2 and R 3 are each independently selected from an aryl group or an alkyl group.

[0014] Further, in the step (1), the mass ratio of the inorganic layered silicate nanomaterial, the inorganic mineral filler, the quaternary ammonium salt organic compound to the polyester is 1-10:1-10:0.2-2:80-99.

[0015] Further, in the step (1), the melt blending temperature is 240 °C to 280 °C.

[0016] Further, the preparation process of the fiber in the step (2) includes:

[0017] Using the polyester masterbatch and the modified polyester masterbatch as the island phase and the alkali-soluble polyester as the sea phase, performing bicomponent composite spinning, pulling out the nascent fiber through a twin-screw melt spinning machine, and then obtaining the polyester fiber with a sea-island structure through cooling and drawing; and then dissolving the sea phase with an alkali solution to obtain the moisture-absorbing and heat-generating polyester fiber.

[0018] Further, in the step (2), the mass ratio of the island phase to the sea phase is 50-80:20-50.

[0019] Further, in the step (2), the mass ratio of the polyester masterbatch to the modified polyester masterbatch in the island phase is 80-99:1-20.

[0020] Further, in the step (2), the spinning temperature is 260°C to 280°C.

[0021] Further, in the step (2), the fiber is opened by treatment with an alkali solution to dissolve the sea phase. The alkali solution contains NaOH with a mass concentration of 2% to 10%, the fiber opening temperature is 90°C to 100°C, and the treatment time is 10 min to 30 min.

[0022] The present invention also provides a moisture-absorbing and heat-generating polyester fiber, which is an ultrafine fiber and is obtained by opening the polyester fiber with a sea-island structure.

[0023] The polyester fiber with a sea-island structure includes an island component and a sea component. The island component includes polyester and modified polyester, and the sea component includes alkali-soluble polyester.

[0024] The modified polyester is prepared by shear blending of an inorganic layered silicate nanomaterial, an inorganic mineral filler, a quaternary ammonium salt organic compound and polyester in a molten state.

[0025] Further, the island component includes 1% to 20% by mass of the modified polyester.

[0026] Further, the polyester fiber with a sea-island structure includes 50% to 80% by mass of the island component.

[0027] Further, the modified polyester is prepared by shear blending of an inorganic layered silicate nanomaterial, an inorganic mineral filler, a quaternary ammonium salt organic compound and polyester in a molten state with a mass ratio of 1 to 10:1 to 10:0.2 to 2:80 to 99.

[0028] Further, the moisture-absorbing and heat-generating polyester fiber is prepared by the method as described above.

[0029] As described above, the moisture-absorbing and heat-generating polyester fiber and its preparation method of the present invention have the following beneficial effects:

[0030] 1. The moisture-absorbing and heat-generating polyester fiber of the present invention has excellent moisture-absorbing and heat-generating performance: The polyester polymer is modified for moisture absorption and heat generation by using an inorganic layered silicate nanomaterial @ inorganic mineral filler composite material, so that the fiber surface has more hydrophilic groups and can absorb water molecules in the air and release heat. The large specific surface area of the ultrafine fiber increases the contact surface between the fiber and the air, improves the moisture absorption performance of the fiber, and enables more moisture-absorbing groups on the fiber surface to be modified, so as to give full play to the moisture absorption effect of the inorganic layered silicate nanomaterial @ inorganic mineral filler composite material. By simultaneously controlling the fiber morphology and hydrophilic modification, a synergistic effect is exerted, and the moisture-absorbing and heat-generating performance of the polyester fiber is greatly improved.

[0031] 2. The moisture-absorbing and heat-generating polyester fiber of the present invention has good mechanical properties: By adding quaternary ammonium salt organic compounds as organic modifiers, on the one hand, it can change the originally incompatible property between inorganic layered silicate nanomaterials and polymers, solve the problem of incompatibility between conventional functional additives and polyester polymers, improve the compatibility and dispersibility of inorganic layered silicate nanomaterial @ inorganic mineral filler composites in polyester polymers, and is beneficial to subsequent spinning and fiber mechanical properties, etc.; on the other hand, through the quaternary ammonium salt, the interlayer spacing of inorganic layered silicate nanomaterials can be expanded, which is beneficial to the dispersion and adhesion of inorganic mineral fillers between the layers of inorganic layered silicate nanomaterials, avoid the agglomeration phenomenon of nanomaterials, ensure the stability of the melt viscosity during granulation or spinning, improve the fluidity during extrusion processing, and improve the stability during fiber forming processing, thereby improving the mechanical properties of the fiber and also being beneficial to improving its compatibility with polyester polymers. Through the organic modification of inorganic layered silicate nanomaterials, their compatibility with the polyester polymer matrix is increased, ensuring their dispersibility in the polymer matrix; at the same time, the addition amount of the modified polyester masterbatch is controlled within a reasonable range, which has little impact on the mechanical properties of the fiber, ensuring the spinnability and wearing performance of the fiber.

[0032] 3. The preparation process of the moisture-absorbing and heat-generating polyester fiber of the present invention is simple and the cost is low: The present invention uses the melt intercalation method to intercalate and modify inorganic layered silicate nanomaterials. This method does not use solvents, has a simple process, is convenient for processing, and can reduce environmental pollution. At the same time, the sea-island fiber is prepared by melt blending and spinning to obtain the moisture-absorbing and heat-generating polyester fiber with an ultrafine morphology. The process is simple, easy for industrial production, and the cost is low. Specific embodiments

[0033] The following specific examples illustrate the implementation manners of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific implementation manners, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0034] In the present invention, unless otherwise specified, the term "a plurality of" means two or more.

[0035] The character " / " means that the objects before and after are in an "or" relationship. For example, A / B means: A or B.

[0036] The term "and / or" is an associative relationship describing objects, indicating that three relationships can exist. For example, A and / or B means: A or B, or, the three relationships of A and B.

[0037] The present invention provides a moisture-absorbing and heat-generating polyester fiber and a preparation method thereof.

[0038] One embodiment of the present invention provides a moisture-absorbing and heat-generating polyester fiber, which is an ultrafine fiber obtained by delaminating a polyester fiber with a sea-island structure; the polyester fiber with a sea-island structure includes an island component and a sea component, the island component includes polyester and modified polyester, and the sea component includes alkali-soluble polyester; the modified polyester is prepared by shear blending of an inorganic layered silicate nanomaterial, an inorganic mineral filler, a quaternary ammonium salt organic compound and polyester in a molten state.

[0039] The present invention uses an inorganic mineral filler and a quaternary ammonium salt organic compound to intercalate and modify the inorganic layered silicate nanomaterial by the melt intercalation method, and then uses the inorganic layered silicate nanomaterial@inorganic mineral filler composite material to modify the polyester polymer for moisture absorption and heat generation, so that the fiber surface has more hydrophilic groups, which can absorb water molecules in the air and release heat. The large specific surface area of the ultrafine fiber increases the contact area between the fiber and the air, improves the moisture absorption performance of the fiber, and enables more hygroscopic groups on the fiber surface to be modified, thus giving full play to the moisture absorption effect of the inorganic layered silicate nanomaterial@inorganic mineral filler composite material. By simultaneously controlling the fiber morphology and hydrophilic modification, a synergistic effect is exerted, greatly improving the moisture absorption and heat generation performance of the polyester fiber.

[0040] The present invention uses a quaternary ammonium salt organic compound as an organic modifier. On the one hand, it can change the property of the inorganic layered silicate nanomaterial that is originally incompatible with the polymer, solve the problem of incompatibility between conventional functional additives and polyester polymers, improve the compatibility and dispersibility of the inorganic layered silicate nanomaterial@inorganic mineral filler composite material in the polyester polymer, and is beneficial to subsequent spinning and fiber mechanical properties; on the other hand, the quaternary ammonium salt can expand the layer spacing of the inorganic layered silicate nanomaterial, which is beneficial to the dispersion and attachment of the inorganic mineral filler between the layers of the inorganic layered silicate nanomaterial, avoiding the agglomeration of the nanomaterials, ensuring the stability of the melt viscosity during granulation or spinning, improving the fluidity during extrusion processing, and improving the stability during fiber forming processing, thereby improving the mechanical properties of the fiber and also being beneficial to improving its compatibility with the polyester polymer.

[0041] In addition, the present invention uses the melt intercalation method to intercalate and modify the inorganic layered silicate nanomaterial. This method does not use solvents, has a simple process, is convenient for processing, and can reduce environmental pollution.

[0042] In some embodiments, the island component comprises 1% to 20% by mass of a modified polyester and 80% to 99% by mass of a polyester; preferably, the island component comprises 3% to 20% by mass of a modified polyester and 80% to 97% by mass of a polyester. Exemplarily, the polyester includes, but is not limited to, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyarylate (PAR), polyethylene terephthalate-1,4-cyclohexanedimethanol ester (PETG), etc. Controlling the addition amount of the modified polyester within the above range has little impact on the mechanical properties of the fiber, ensuring the spinnability and wearing performance of the fiber.

[0043] In some embodiments, the polyester fiber having a sea-island structure comprises 50% to 80% by mass of an island component and 20% to 50% by mass of a sea component.

[0044] In some embodiments, the modified polyester is prepared by shear blending an inorganic layered silicate nanomaterial, an inorganic mineral filler, a quaternary ammonium salt organic compound and a polyester in a molten state in a mass ratio of 1 to 10:1 to 10:0.2 to 2:80 to 99.

[0045] Another embodiment of the present invention provides a method for preparing the moisture-absorbing and heat-generating polyester fiber as described in the above embodiment / embodiments, comprising the following steps:

[0046] (1) Preparation of the modified polyester masterbatch:

[0047] Shear blend the inorganic layered silicate nanomaterial, the inorganic mineral filler, the quaternary ammonium salt organic compound and the polyester in a molten state, and extrude and pelletize to prepare the modified polyester masterbatch;

[0048] (2) Preparation of the fiber:

[0049] Use the polyester masterbatch and the modified polyester masterbatch as the island phase, and an alkali-soluble polyester as the sea phase to form a polyester fiber having a sea-island structure, and then dissolve the sea phase to obtain the moisture-absorbing and heat-generating polyester fiber.

[0050] In some embodiments, the inorganic layered silicate nanomaterial is selected from at least one of montmorillonite, sodium-based montmorillonite, calcium-based montmorillonite, kaolinite, vermiculite or mica, the inorganic mineral filler is selected from at least one of silica, titanium dioxide, talcum powder or calcium carbonate, and the quaternary ammonium salt organic compound has the following structure: CH 3 (CH 2 )nNH 3 + ,CH 3 (CH 2 )nNH 2+ R 1 ,CH 3 (CH 2 )nNH + R 1 R 2 ,CH 3 (CH 2 )nN + R 1 R 2 R 3 wherein, 1≤n≤18, R 1 、R 2 and R 3 are each independently selected from an aryl group or an alkyl group, and the alkyl group is selected from alkyl groups having 1 to 6 carbon atoms. Exemplarily, the quaternary ammonium salt organic compound includes but is not limited to dodecyl trimethyl ammonium chloride, cetyl trimethyl ammonium chloride, octadecyl trimethyl ammonium chloride, dodecyl dimethyl benzyl ammonium chloride, octadecyl dimethyl benzyl ammonium chloride, etc.

[0051] In some embodiments, in the step (1), the mass ratio of the inorganic layered silicate nanomaterial, the inorganic mineral filler, the quaternary ammonium salt organic compound to the polyester is 1 to 10:1 to 10:0.2 to 2:80 to 99.

[0052] In some embodiments, in the step (1), the melt blending temperature is 240°C to 280°C.

[0053] In some embodiments, the preparation process of the fiber in the step (2) includes: using the polyester masterbatch and the modified polyester masterbatch as the island phase, and using the alkali-soluble polyester as the sea phase, performing bicomponent composite spinning, pulling out the nascent fiber through a twin-screw melt spinning machine, and then obtaining the polyester fiber with a sea-island structure through cooling and drawing; then dissolving the sea phase with an alkali solution to obtain the moisture-absorbing and heat-generating polyester fiber. Using melt blending spinning to prepare sea-island fibers, the obtained moisture-absorbing and heat-generating polyester fiber has an ultrafine morphology, and has the advantages of simple process, easy industrial production, and low cost.

[0054] In some embodiments, in the step (2), the mass ratio of the island phase to the sea phase is 50 to 80:20 to 50.

[0055] In some embodiments, in the step (2), the mass ratio of the polyester masterbatch to the modified polyester masterbatch in the island phase is 80 to 99:1 to 20, preferably 80 to 97:3 to 20. Controlling the addition amount of the modified polyester masterbatch within the above range has little influence on the mechanical properties of the fiber, and ensures the spinnability and wearing performance of the fiber.

[0056] In some embodiments, in the step (2), the spinning temperature is 260°C to 280°C.

[0057] In some embodiments, in step (2), an alkali solution is used for fiber opening treatment to dissolve the sea phase. The alkali solution contains 2% - 10% NaOH by mass concentration, the fiber opening temperature is 90°C - 100°C, and the treatment time is 10 min - 30 min.

[0058] Specific examples of the embodiments are given below to illustrate the present invention in detail. It should be understood that the following embodiments are only used to specifically illustrate the present invention and should not be construed as limiting the protection scope of the present invention. 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.

[0059] Example 1

[0060] This example provides a moisture-absorbing and heat-generating polyester fiber, and its preparation method steps are as follows:

[0061] (1) Preparation of modified polyester masterbatch:

[0062] Montmorillonite (MMT) 10%, SiO 2 5%, octadecyltrimethylammonium chloride 1%, PET 84%. They are mixed evenly in a high-speed mixer and then added to a screw extruder. The temperature is set at 275°C, and through high-temperature melting and shearing, they are extruded and pelletized to obtain the modified polyester masterbatch.

[0063] (2) Preparation of fibers:

[0064] 95% of conventional PET masterbatch and 5% of the above-mentioned modified polyester masterbatch are mixed in proportion as the island phase, and alkali-soluble polyester (COPET) is selected as the sea phase.

[0065] The composite ratio of the island component and the sea component is controlled to be 70:30, and they are respectively added to different feeding ports for bicomponent composite spinning. The spinning temperature is set at 280°C, and the as-spun fiber is drawn out through a twin-screw melt spinning machine, and then obtained as a polyester fiber with a sea-island structure after cooling and drawing.

[0066] The polyester fiber is subjected to fiber opening treatment in an 8% NaOH alkali solution at a temperature of 95°C for 25 min; then it is washed and dried to obtain the moisture-absorbing and heat-generating polyester fiber.

[0067] Example 2

[0068] This example provides a moisture-absorbing and heat-generating polyester fiber, and its preparation method steps are as follows:

[0069] (1) Preparation of modified polyester masterbatch:

[0070] Montmorillonite (MMT) 1%, SiO 2 1%, octadecyltrimethylammonium chloride 0.2%, PET 97.8%, are mixed evenly in a high-speed mixer, added to a screw extruder, the temperature is set at 275 °C, and through high-temperature melting and shearing, extrusion and pelletization are carried out to obtain the modified polyester masterbatch.

[0071] (2) Preparation of fibers:

[0072] 80% of the conventional PET masterbatch and 20% of the above-mentioned modified polyester masterbatch are mixed in proportion as the island phase, and alkali-soluble polyester (COPET) is selected as the sea phase.

[0073] Control the composite ratio of the island component and the sea component to be 80:20, add them to different feeding ports respectively, carry out bicomponent composite spinning, set the spinning temperature at 280 °C, pull out the nascent fiber through a twin-screw melt spinning machine, and then obtain the polyester fiber with a sea-island structure through cooling and drawing.

[0074] The polyester fiber is subjected to fiber opening treatment in an 8% NaOH alkali solution at a temperature of 95 °C for 25 min; then it is washed and dried to obtain the moisture-absorbing and heat-generating polyester fiber.

[0075] Example 3

[0076] This example provides a moisture-absorbing and heat-generating polyester fiber, and its preparation method steps are as follows:

[0077] (1) Preparation of the modified polyester masterbatch:

[0078] Montmorillonite (MMT) 8%, SiO 2 10%, octadecyltrimethylammonium chloride 2%, PET 80%, are mixed evenly in a high-speed mixer, added to a screw extruder, the temperature is set at 275 °C, and through high-temperature melting and shearing, extrusion and pelletization are carried out to obtain the modified polyester masterbatch.

[0079] (2) Preparation of fibers:

[0080] 97% of the conventional PET masterbatch and 3% of the above-mentioned modified polyester masterbatch are mixed in proportion as the island phase, and alkali-soluble polyester (COPET) is selected as the sea phase.

[0081] Control the composite ratio of the island component and the sea component to be 50:50, add them to different feeding ports respectively, carry out bicomponent composite spinning, set the spinning temperature at 280 °C, pull out the nascent fiber through a twin-screw melt spinning machine, and then obtain the polyester fiber with a sea-island structure through cooling and drawing.

[0082] The polyester fiber was fibrillated in an 8% NaOH alkaline solution at 95°C for 25 min; then it was washed and dried to obtain the moisture-absorbing and heat-generating polyester fiber.

[0083] Fiber property test:

[0084] 1. The moisture-absorbing and heat-generating properties of the polyester fibers prepared in Examples 1 to 3 were detected, and the results are shown in Table 1.

[0085] Table 1 Detection results of moisture-absorbing and heat-generating properties

[0086]

[0087] "*" indicates not within the authorization scope of CANS, CMA, and CAL.

[0088] As can be seen from Table 2, the maximum temperature rise value of the moisture-absorbing and heat-generating polyester fiber is 10°C, and the average temperature rise value within 30 min is 4.8°C, both meeting the standard requirements. When the moisture-absorbing and heat-generating properties of ordinary polyester were detected by the same method, the results showed that its maximum temperature rise value was 0.6°C, and the average temperature rise value within 30 min was 0.2°C. Thus, it can be seen that the polyester fiber provided by the present invention has good moisture-absorbing and heat-generating properties.

[0089] 2. The fineness of the moisture-absorbing and heat-generating polyester fibers prepared in Examples 1 to 3 was tested in accordance with "GB / T 14343-2008 Chemical Fibers - Test Method for Filament Linear Density", and the mechanical properties of the moisture-absorbing and heat-generating polyester fibers prepared in Examples 1 to 3 were determined in accordance with "GB / T 14344-2022 Test Method for Tensile Properties of Chemical Fiber Filaments". The results are shown in Table 2.

[0090] Table 2 Mechanical properties of moisture-absorbing and heat-generating polyester fibers

[0091] Test items Fineness (dtex) Breaking strength (cN / dtex) Elongation at break (%) Example 1 0.10 3.11 33.27 Example 2 0.11 3.23 35.52 Example 3 0.07 2.98 29.55

[0092] For conventional polyester fibers, their mechanical properties vary to some extent according to their actual fineness. Generally, for ultra-fine fibers, the required breaking strength is ≥2.0 cN / dtex. As can be seen from Table 2, the strengths of the fibers in Examples 1 to 3 are all higher than the conventional required indexes, and the elongation at break is also within a reasonable range. Thus, it can be seen that the moisture-absorbing and heat-generating polyester fibers in Examples 1 to 3 of the present invention not only have extremely low fineness but also maintain the mechanical properties of conventional polyester fibers, which indicates that the moisture-absorbing and heat-generating polyester fiber provided by the present invention is an ultra-fine fiber and has good mechanical properties.

[0093] The above embodiments are only illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. A method for preparing a hygroscopic and heat-generating polyester fiber, characterized in that: The steps include: (1) Preparation of modified polyester masterbatch: The inorganic layered silicate nanomaterial, the inorganic mineral filler, the quaternary ammonium salt organic compound and the polyester are shear-blended in a molten state, and extruded into granules to prepare a modified polyester masterbatch; (2) Preparation of fibers: The polyester masterbatch and the modified polyester masterbatch are used as the island phase, and the alkali-soluble polyester is used as the sea phase to prepare the polyester fiber with the sea-island structure, and then the sea phase is dissolved to obtain the hygroscopic heat-generating polyester fiber.

2. The method for preparing the hygroscopic heat-generating polyester fiber according to claim 1, characterized in that: The inorganic layered silicate nanomaterial is selected from at least one of montmorillonite, sodium montmorillonite, calcium montmorillonite, kaolinite, vermiculite or mica; and / or, the inorganic mineral filler is selected from at least one of silicon dioxide, titanium dioxide, talc or calcium carbonate; And / or, the quaternary ammonium salt organic compound has the following structure: CH3(CH2)nNH3 + , CH3(CH2)nNH2 + R1, CH3(CH2)nNH + R1R2,CH3(CH2)nN + R1R2R3, wherein 1≤n≤18, and R1, R2 and R3 are each independently selected from an aromatic group or an alkyl group.

3. The method for preparing the hygroscopic heat-generating polyester fiber according to claim 1 or 2, characterized in that: In the step (1), the mass ratio of the inorganic layered silicate nanomaterial, the inorganic mineral filler, the quaternary ammonium salt organic compound and the polyester is 1-10:1-10:0.2-2:80-99.

4. The method for preparing the hygroscopic heat-generating polyester fiber according to claim 1, characterized in that: In the step (1), the melt blending temperature is 240°C to 280°C.

5. The method for preparing the hygroscopic heat-generating polyester fiber according to claim 1, characterized in that: The fiber preparation process in step (2) comprises: The polyester masterbatch and the modified polyester masterbatch are used as the island phase, and the alkali-soluble polyester is used as the sea phase to carry out two-component composite spinning, and the primary fiber is pulled out by a twin-screw melt spinning machine, and then the polyester fiber with a sea-island structure is obtained by cooling and drawing; and the sea phase is dissolved by an alkaline solution to obtain the hygroscopic and heat-generating polyester fiber.

6. The method for preparing the hygroscopic heat-generating polyester fiber according to claim 1 or 5, characterized in that: In the step (2), the mass ratio of the island phase to the sea phase is 50-80:20-50; And / or, in the step (2), the mass ratio of the polyester masterbatch to the modified polyester masterbatch in the island phase is 80-99:1-20.

7. The method for preparing the hygroscopic heat-generating polyester fiber according to claim 1 or 5, characterized in that: In the step (2), the spinning temperature is 260°C to 280°C; And / or, in the step (2), an alkaline solution is used for fiber opening treatment to dissolve the sea phase, the alkaline solution contains NaOH with a mass concentration of 2% to 10%, the fiber opening temperature is 90°C to 100°C, and the treatment time is 10min to 30min.

8. A hygroscopic and heat-generating polyester fiber, characterized in that: The moisture-absorbing and heat-generating polyester fiber is an ultrafine fiber obtained by opening a polyester fiber with a sea-island structure; The polyester fiber with a sea-island structure comprises an island component and a sea component, wherein the island component comprises polyester and modified polyester, and the sea component comprises alkali-soluble polyester; The modified polyester is prepared by shearing and blending inorganic layered silicate nanomaterials, inorganic mineral fillers, quaternary ammonium salt organic compounds and polyester in a molten state.

9. The hygroscopic and heat-generating polyester fiber according to claim 8, characterized in that: The island component includes 1% to 20% by mass of modified polyester; And / or, the polyester fiber with sea-island structure comprises 50% to 80% by mass of island components; And / or, the modified polyester is prepared by shear blending inorganic layered silicate nanomaterials, inorganic mineral fillers, quaternary ammonium salt organic compounds and polyester in a mass ratio of 1-10:1-10:0.2-2:80-99 in a molten state.

10. The hygroscopic heat-generating polyester fiber according to claim 9, characterized in that: The hygroscopic and heat-generating polyester fiber is prepared by the method according to any one of claims 1 to 7.

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