Pore intelligent regulation weft-knitted fabric and preparation method thereof

Abstract

The application discloses a kind of pore intelligent regulation weft knitted fabric, including face yarn and ground yarn, the face yarn with the ground yarn is interwoven by plating weft knitting process, forms fabric body, in the process front of fabric body, by the face yarn constitute several regular distribution pore regulation unit;The pore regulation unit is in dry state, present closed or shrinkage form;In hygroscopic state, the pore regulation unit expands, forms the air-permeable channel in the thickness direction of fabric body.The application utilizes the "moisture absorption axial elongation, radial shrinkage and twist to high humidity side" characteristics of face yarn in heat and humidity response yarn, and cooperates with the size stable support of ground yarn, gives the dynamic pore regulation ability of fabric body;When human perspires, face yarn absorbs moisture and elongates and twists, pore regulation unit actively expands, forms three-dimensional air-permeable channel, enhances heat dissipation and moisture removal;After drying, yarn restores, pore closes to reduce air convection to keep warm.

Description

Technical Field

[0001] This invention relates to the field of smart fabric technology, and in particular to a weft-knitted fabric with intelligent pore control. Background Technology

[0002] The development of modern functional textiles has placed higher demands on the thermal and moisture comfort of clothing, especially in scenarios such as sports, outdoor activities, and special operations. During strenuous activity, the human body generates a large amount of sweat and heat. If this heat cannot be dissipated in time, it will lead to stuffiness, stickiness, and other discomforts, and may even affect physiological health. Therefore, developing fabrics with intelligent thermal and moisture management functions has become an important research direction.

[0003] Currently, the mainstream technical approaches to improving the breathability and moisture-wicking performance of fabrics mainly include: using moisture-wicking and quick-drying fibers or applying hydrophilic finishing; designing multi-layer composite structures to achieve unidirectional moisture wicking using capillary effects; and constructing static micropores or uneven structures in the fabric to increase specific surface area and air circulation. For example, by using complex loop and coil combination structures to form uniform static micropores on the fabric surface, double-sided breathability is improved, but the pore size is fixed and cannot adaptively adjust according to environmental changes.

[0004] In summary, existing technologies mostly focus on unidirectional and static management of moisture or heat, lacking a fabric structure capable of dynamically, bidirectionally, and intelligently adjusting its pore structure according to ambient temperature and humidity to achieve an adaptive thermal-humidity balance through a "hot-opening, cold-closing" mechanism. Specifically, existing designs exhibit a contradiction between enhancing heat dissipation in humid and hot conditions and restoring heat retention efficiency in dry conditions, making it difficult to achieve efficient and reversible dynamic control on a single fabric. Summary of the Invention

[0005] The purpose of this invention is to provide a weft-knitted fabric with intelligent pore control to solve the problem mentioned in the background art that the pore structure of weft-knitted fabrics is static and cannot respond to dynamic changes in environmental temperature and humidity to achieve optimal thermal and humidity comfort.

[0006] To achieve the above objectives, in a first aspect, the present invention provides a weft-knitted fabric with intelligent pore control, comprising: a face yarn, including at least one heat- and moisture-responsive yarn, the heat- and moisture-responsive yarn having reversible moisture absorption and elongation characteristics, capable of elongating axially and shrinking radially after absorbing moisture, and generating torsional deformation from the radial low-moisture side to the high-moisture side, and capable of essentially returning to its initial state after drying; a base yarn, serving as a structural support yarn, including at least one low-moisture-absorbing yarn, capable of maintaining dimensional stability in high-humidity environments to maintain the basic structure of the fabric; the face yarn and the base yarn are interwoven through a weft-knitting process to form a fabric body having a process front and a process back; on the process front of the fabric body, the face yarn constitutes a plurality of regularly distributed pore control units; the pore control units are configured such that: in a dry state, the heat- and moisture-responsive yarn is in a non-elongated state, causing the pore control units to be in a closed or contracted state; in a moisture-absorbing state, the heat- and moisture-responsive yarn generates elongation and torsional deformation, driving the pore control units to expand, forming breathable channels in the thickness direction of the fabric body.

[0007] Furthermore, the minimum tissue circulation flower height of the porosity control unit is 6-32 channels, and the flower width is 4-36 needles.

[0008] Furthermore, within the porosity control unit, the heat and moisture responsive yarn is presented in a composite knitting structure of "tuck + plain knit", "float + plain knit", "float + loose loop + plain knit", or "dangling loop + loose loop + plain knit".

[0009] Furthermore, the axial elongation of the heat and moisture responsive yarn after moisture absorption is 15%-40%.

[0010] Furthermore, the base yarn is selected from one or more of polyester, spandex, polypropylene and their blended yarns; the heat and moisture responsive yarn is selected from one or more of heat and moisture elongation polyester, heat and moisture elongation nylon, heat and moisture elongation wool yarn, or a parallel or core-sheath composite yarn composed of at least two components with different radial heat and moisture expansion coefficients.

[0011] Furthermore, the yarn comprises a variety of heat and moisture responsive yarns with different elongation rates to form differentiated porosity control responses.

[0012] Furthermore, the fabric body includes at least a first functional zone and a second functional zone; wherein, the first functional zone uses a first heat and moisture responsive yarn with an axial elongation of 15%-30% after moisture absorption; and the second functional zone uses a second heat and moisture responsive yarn with an axial elongation of 30%-40% after moisture absorption.

[0013] Furthermore, the total content of the heat and moisture responsive yarn accounts for 50%-90% of the total mass of the weft-knitted fabric.

[0014] On the other hand, the present invention provides a method for preparing the above-mentioned intelligent pore control weft-knitted fabric, comprising the following steps: S1, selecting at least one heat-moisture responsive yarn as the face yarn, wherein the heat-moisture responsive yarn has reversible moisture absorption and elongation characteristics, and the axial elongation rate after moisture absorption is 15%-40%, and it can basically recover after drying; selecting at least one low moisture absorption yarn as the base yarn; S2, using a weft knitting process to interweave the face yarn and the base yarn, controlling the face yarn to cover the front side of the fabric process throughout the process, and the base yarn to be exposed on the reverse side of the fabric process, forming a stable double-layer structure; S3, during the knitting process, according to a preset pattern program, within an area where the minimum weave repeat height is 6-32 rows and the pattern width is 4-36 stitches, controlling the face yarn to be knitted in a local combination of "tuck + plain stitch", "float + plain stitch", "float + loose loop + plain stitch" or "dangling stitch + loose loop + plain stitch", forming a pore control unit that presents a closed shape in the dry state.

[0015] Compared with the prior art, the beneficial effects of the present invention are: This invention overcomes the limitations of traditional fabrics with fixed pore sizes. It utilizes the "moisture absorption axial elongation, radial shrinkage, and twisting towards the high-humidity side" characteristics of the heat- and moisture-responsive yarn in the face yarn, combined with the dimensional stability support of the base yarn, to give the fabric dynamic pore control capabilities. When the human body sweats, the face yarn absorbs moisture, elongates, and twists, driving the pore control unit to actively expand, forming a three-dimensional breathable channel to enhance heat dissipation and moisture removal. After drying, the yarn recovers, and the pores close to reduce air convection and retain heat. This mechanism achieves a biomimetic effect similar to the "heat opening and cold closing" of human pores, achieving a balance between heat dissipation and heat retention in a single fabric. By utilizing the elongation and torsional deformation of the heat- and moisture-responsive yarns, the area and three-dimensionality of the breathable channels in the fabric increase after moisture absorption. This effectively solves the problem of decreased breathability caused by fiber swelling and clogging of pores in traditional unidirectional moisture-wicking fabrics after moisture absorption. At the same time, due to the reversible physical properties of the response mechanism, the wet breathability remains good after wet-dry cycles, exhibiting excellent durability and stability. This invention employs a mature weft knitting process for one-time molding, and through localized needlework combinations, the required pore control units can be precisely constructed, resulting in a highly efficient process and controllable quality. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the cross-sectional structure of the fabric along the thickness direction in the dry state according to the present invention; Figure 2 This is a schematic diagram of the cross-sectional structure of the fabric along the thickness direction after moisture absorption according to the present invention; Figure 3 This is a schematic diagram of the force and opening mechanism of the pore control unit of the present invention under hygroscopic conditions; Figure 4 This is a weaving pattern diagram of the fabric in the first embodiment of the present invention; Figure 5This is a diagram showing the arrangement of knitting needles and the triangular arrangement of the fabric when it is mounted on the machine, as shown in the first embodiment of the present invention. Figure 6 This is a comparison diagram of the pore morphology of the fabric in the dry state and the moisture-absorbing state in the first embodiment of the present invention; Figure 7 The graph shows the air permeability test results of the fabric of the present invention and the comparative fabric under different moisture absorption levels. Figure 8 This is a weaving pattern of the fabric in the second embodiment of the present invention.

[0017] Figure 9 This is a diagram showing the needle arrangement and triangular arrangement of the fabric during the fabric loading process in the second embodiment of the present invention. Figure 10 This is a schematic diagram illustrating the application of different elongation rates and heat- and moisture-responsive yarns in this invention.

[0018] In the diagram: 1. Face yarn; 2. Bottom yarn; 11. Pore control unit; 3. First functional zone; 4. Second functional zone. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] like Figures 1-9 As shown, the present invention provides a weft-knitted fabric with intelligent porosity control, comprising: Yarn 1 includes at least one heat and moisture responsive yarn, which has reversible moisture absorption and elongation characteristics. After absorbing moisture, it can elongate axially and shrink radially, and generate torsional deformation from the radial low moisture side to the high moisture side, and can basically return to its initial state after drying. The base yarn 2, as a structural support yarn, contains at least one low-hygroscopic yarn that can maintain dimensional stability in high-humidity environments to maintain the basic structure of the fabric. The face yarn 1 and the base yarn 2 are interwoven through a weft knitting process to form a fabric body with a process front and a process back; on the process front of the fabric body, the face yarn 1 forms a number of regularly distributed pore control units 11. The pore control unit 11 is configured such that: in a dry state, the heat and moisture responsive yarn is in a non-stretched state, causing the pore control unit 11 to be in a closed or contracted state; in a moisture-absorbing state, the heat and moisture responsive yarn undergoes elongation and torsional deformation, driving the pore control unit 11 to expand and form a breathable channel in the thickness direction of the fabric body.

[0021] In this embodiment, the specific process and material selection are as follows: The face yarn 1 can be made of 75D heat- and moisture-stretching nylon filament, which is length-stable under standard temperature and humidity (20°C, 65%RH) and can produce an axial elongation of about 35.6% in an environment of 35°C and 90% relative humidity; the base yarn 2 can be made of 50D / 24F polyester filament. The equipment used is a Santoni seamless circular knitting machine, model number E28, with a machine cylinder diameter of 15 inches, a total of 8 yarn feeding channels, a machine speed of 70 r / min, a total of 1344 needles, a yarn feeding tension of 2.5cN, and a density control position of P1; The minimum design length for the repeating pattern is 28 stitches, and the pattern width is 26 stitches; in this case, the face yarn 1 and the base yarn 2 are simultaneously threaded into each stitch.

[0022] Its weaving design pattern is as follows Figure 4 As shown in the diagram, yarn A1 is the base yarn and yarn B1 is the face yarn; The specific weaving rules are as follows: White empty squares indicate that only the face yarn 1 is looped on the needle; dark empty squares indicate that both the base yarn 2 and the face yarn 1 are looped on the needle, forming the basic weft plain knit structure commonly found in seamless sportswear; - squares indicate that the needle selection system does not perform a yarn padding operation. In this case, the face yarn 1 is left as a float on the back of the fabric. If multiple passes are not padded, elongated loops will be formed on the machine, causing the fabric to shrink longitudinally under the tension of the loops after leaving the machine, producing a pleated effect and gathering the mesh formed by the loop shedding; × squares indicate that a loop shedding action is performed. Continuous loop shedding actions cause the face yarn 1 to form narrow loop shedding meshes.

[0023] The needle arrangement diagram and tactical diagram for fabric loading are as follows: Figure 5 As shown; like Figure 3 As shown, under hygroscopic conditions, the heat- and moisture-responsive yarns on both sides of the loop-out mesh are subjected to an axial elongation driving force F. h1 F h2 With lateral opening force F w1 F w2 The combined effect of these elements causes the mesh openings to expand outward from both ends a and b, thereby creating breathable channels in the fabric thickness direction.

[0024] Where Fh1 and Fw1 are the axial elongation driving force and lateral opening force acting on the recessed area at the edge of the mesh. Fh2 and Fw2 are the axial elongation driving force and lateral opening force acting on the protruding area at the edge of the mesh. a and b are the approximate width and height of the recessed area, respectively.

[0025] To address the axial force generated by yarn moisture absorption, the fabric plane is approximated as a two-dimensional plane, and the recessed pore unit is approximated as an elliptical hole. Then, the stress concentration factors Kt1=1+b / 2a, Kt2=1+2b / a, that is, Fw1=Kt1Fw2, Fh1=Kt2Fh2. Therefore, Fw1>Fw2, Fh1>Fh2, thus the recessed area expands.

[0026] When one side of the environment is humid and the other side is dry, it twists towards the humid direction, with the maximum twist angle reaching 70°.

[0027] like Figure 6 As shown, in a dry state, yarn 1 is relaxed. When the body is active and sweating, the yarns on both sides of the loop-out mesh have greater stress concentration, resulting in greater response and elongation, thus increasing the area of ​​the loop-out mesh. The response of the protruding part is less than that of the concave area, therefore its area is smaller, and it arches upward, making the breathable channels more three-dimensional. This process increases the effective breathable area of ​​the fabric, increases the heat convection rate, and accelerates sweat evaporation and heat dissipation. When the body stops exercising and the skin returns to dryness and coolness, the yarns recover, the area of ​​the loop-out mesh decreases, the protruding part becomes larger and flatter, and it returns to its original state. The fabric weight in this embodiment is approximately 151 g / m². 2 The heat and moisture responsive yarn content is approximately 60%. For example... Figure 7 As shown in the test, under simulated sweating conditions, the wet breathability of this invention can be increased by more than 150% compared to the dry state, while the breathability of conventional one-way moisture-wicking fabrics decreases with moisture absorption. After 50 wet-dry cycles, its wet breathability can still reach more than 145% of the dry state, and the performance retention rate is more than 90%.

[0028] As another embodiment of the present invention, a seamless underwear machine with machine number E28, a cylinder diameter of 15 inches, and a total of 1344 needles is selected. The face yarn 1 is made of 70D / 24F wet-responsive nylon, which has an axial elongation of 35% and a wet axial expansion stress of 0.18 cN / dtex when the relative humidity increases from 40% to 90%, exhibiting excellent moisture-driven performance. The base yarn 2 is made of 70D / 36F polyester / spandex core-spun yarn with a moisture regain of 1.3% and an elastic recovery rate of 95%, used to provide a local constraint skeleton. Based on the percentage of loops in the fabric, the face yarn 1 contains 81.25% and the base yarn 2 contains 18.75%, meaning that the elastic yarn content is 23% of the wet-responsive yarn content. This ratio can provide sufficient elastic recovery force and honeycomb boundary constraint without significantly restricting wet-responsive deformation.

[0029] The fabric structure employs a partially padded weave, with a surface exhibiting a uniformly distributed hexagonal honeycomb-like lattice structure.

[0030] The main area of ​​the hexagonal honeycomb unit is formed by the face yarn 1 woven with a plain knit weave; the face yarn 1 and the base yarn 2 are woven with a float weave to form a continuous network of recessed slits. The initial thickness of this area is lower than that of the protrusions, and the initial porosity is significantly higher than that of the protrusions. The flower path is set as follows: 8 paths in a cycle. Paths 1-3 are threaded with veil 1 and base veil 2, and the remaining paths are threaded with veil 1 only.

[0031] Its weaving design pattern is as follows Figure 8 As shown in the diagram, yarn A1 is the base yarn and yarn B1 is the face yarn; The specific weaving rules are as follows: White empty squares indicate that only face yarn 1 is looped on the needle; dark empty squares indicate that both base yarn 2 and face yarn 1 are looped on the needle; - squares indicate that the needle selection system does not perform a yarn padding operation, and in this case, face yarn 1 is left as a float on the back of the fabric.

[0032] When the wearer sweats profusely and the relative humidity of the microenvironment close to the skin rises from 40% to approximately 90%: When a wet-response yarn absorbs moisture, it undergoes axial elongation and responsive force. Due to stress concentration, the responsive force is greater in the concave slit than in the convex part. The area of ​​the concave part increases, the porosity of the concave part increases, and the heat and moisture exchange area increases significantly.

[0033] The raised portion, constrained by a hexagonal boundary skeleton forming a strong network, cannot expand inwards. The remaining expansion stress forces the raised portion to arch upwards along the fabric thickness, increasing the arch height. This arching reduces the contact area between the fabric and the skin, lengthens air gaps, enhances breathability and convection, and effectively prevents a sticky feeling after sweating. Figure 7 As shown, the improvement in air permeability driven by wet-response deformation is significant.

[0034] When the skin surface dries and the humidity decreases, the wet response yarn loses water and shrinks, the expansion stress disappears, and the elastic recovery force of the spandex drives the slits to close and the protrusions to flatten, and the fabric returns to its initial honeycomb undulation shape.

[0035] Conventional unidirectional moisture-wicking fabrics typically employ a double-knitted structure. The inner layer (skin-contact layer) uses a plain weave, while the outer layer (diffusion layer) uses a mesh structure (double-sided mesh structure). The inner layer yarns form a point-contact water-repellent layer with a looser loop structure, while the outer layer provides a larger moisture diffusion area and evaporation channels with its mesh structure.

[0036] The inner layer (skin-contact layer) is made of polypropylene, with a content of approximately 40%. Polypropylene does not absorb water, preventing moisture from penetrating the fiber interior. It has natural water-repellent properties, allowing sweat to be repelled from the skin.

[0037] The outer layer (diffusion layer) is made of hydrophilic polyester, with a content of about 60%. Polyester itself has very poor hydrophilicity, but after being processed with irregular cross-sections, tiny grooves are formed on the surface, which can generate a capillary effect to wick away sweat.

[0038] The moisture-wicking principle is based on the dual effects of differential capillary effect and wetting gradient effect.

[0039] The difference between this invention and the present invention in terms of pore response mechanism is that the pore structure of unidirectional moisture-wicking fabrics is statically determined by the fiber raw materials and weaving process, and the porosity and pore size distribution remain fixed after weaving. There is no active response mechanism; it relies solely on the inherent wetting differences of the material for passive moisture wicking. The air permeability test method is carried out in accordance with GB / T 5453-1997 "Determination of air permeability of textile fabrics". The pressure drop on both sides of the sample is 100 Pa, the test area is 20 cm2, and at least 10 different positions are tested for each sample in each test, and the average value is taken. The air permeability of the fabric was measured in the dry state and after being soaked in 30%, 60%, and 90% artificial sweat (to simulate the degree of sweat wetting of the fabric). The method for simulating sweating conditions is as follows: Dissolve 9 g of sodium chloride (NaCl) in 1 L of distilled water to prepare a 0.9% sodium chloride solution. The conductivity of this solution at 25°C should be 16 ± 0.2 mS / cm.

[0040] The number of wet-dry cycles and the determination method are as follows: Air permeability is tested when the sample is dry; air permeability is tested after soaking the sample in artificial sweat to a 90% liquid content; samples undergoing air permeability testing are dried at 40°C to constant weight, which is counted as one wet-dry cycle. The wet and dry air permeability is compared after 50 wet-dry cycles.

[0041] Furthermore, the minimum tissue circulation flower height of the porosity control unit 11 is 6-32 channels, and the flower width is 4-36 needles.

[0042] Furthermore, within the pore control unit 11, the heat and moisture responsive yarn is presented in a composite knitting structure of "tuck + plain knit", "float + plain knit", "float + loose loop + plain knit" or "dangling loop + loose loop + plain knit".

[0043] Furthermore, the axial elongation of the heat and moisture responsive yarn after moisture absorption is 15%-40%.

[0044] Further, the base yarn 2 is selected from one or more of polyester, spandex, polypropylene and their blended yarns; the heat and moisture responsive yarn is selected from one or more of heat and moisture elongation polyester, heat and moisture elongation nylon, heat and moisture elongation wool yarn, or a parallel or core-sheath composite yarn composed of at least two components with different radial heat and moisture expansion coefficients.

[0045] Furthermore, the yarn 1 comprises a variety of heat and moisture responsive yarns with different elongation rates to form differentiated porosity control responses.

[0046] Furthermore, as another embodiment of the present invention, the fabric body includes at least a first functional zone 3 and a second functional zone 4; wherein, the first functional zone 3 adopts a first heat and moisture responsive yarn with an axial elongation of 15%-30% after moisture absorption; and the second functional zone 4 adopts a second heat and moisture responsive yarn with an axial elongation of 30%-40% after moisture absorption.

[0047] like Figure 9 As shown, due to different human perspiration needs, areas with more perspiration can use heat- and moisture-responsive yarns with higher elongation after moisture absorption.

[0048] Furthermore, the total content of the heat and moisture responsive yarn accounts for 50%-90% of the total mass of the weft-knitted fabric.

[0049] The present invention also provides a method for preparing the above-mentioned intelligent porosity control weft-knitted fabric, comprising the following steps: S1. Select at least one heat and moisture responsive yarn as face yarn 1. The heat and moisture responsive yarn has reversible moisture absorption and elongation characteristics. After moisture absorption, the axial elongation rate is 15%-40%, and it can basically recover after drying. Select at least one low moisture absorption yarn as base yarn 2. S2. Using the weft knitting process, the face yarn 1 and the base yarn 2 are interwoven, and the face yarn 1 is controlled to cover the front side of the fabric process throughout the process, while the base yarn 2 is exposed on the back side of the fabric process, forming a stable double-layer structure. S3. During the knitting process, according to the preset pattern program, within an area where the minimum weave cycle height is 6-32 rows and the pattern width is 4-36 stitches, the yarn 1 is controlled to be knitted in a local combination of "tuck + plain stitch", "float + plain stitch", "float + loose loop + plain stitch" or "dangling stitch + loose loop + plain stitch" to form a pore control unit 11 that presents a closed shape in the dry state.

[0050] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A weft-knitted fabric with intelligent pore control, characterized in that, include: The yarn (1) includes at least one heat-moisture responsive yarn, which has reversible moisture absorption and elongation characteristics. After absorbing moisture, it can elongate along the axial direction and shrink radially, and generate torsional deformation from the radial low-moisture side to the high-moisture side. It can basically return to its initial state after drying. The base yarn (2), as a structural support yarn, contains at least one low-hygroscopic yarn that can maintain dimensional stability in a high-humidity environment in order to maintain the basic structure of the fabric. The face yarn (1) and the base yarn (2) are interwoven by the weft knitting process to form a fabric body with a process front and a process back; on the process front of the fabric body, the face yarn (1) constitutes a number of regularly distributed pore control units (11). The pore control unit (11) is configured such that: in the dry state, the heat and moisture responsive yarn is in a non-stretched state, so that the pore control unit (11) is in a closed or contracted state; in the moisture absorbing state, the heat and moisture responsive yarn produces elongation and torsion deformation, driving the pore control unit (11) to expand and form a breathable channel in the thickness direction of the fabric body.

2. The weft-knitted fabric according to claim 1, characterized in that, The minimum tissue circulation flower height of the porosity control unit (11) is 6-32 rows, and the flower width is 4-36 needles.

3. The weft-knitted fabric according to claim 1, characterized in that, Within the pore control unit (11), the heat and moisture responsive yarn is presented in a composite knitting structure of "tuck + plain knit", "float + plain knit", "float + loose loop + plain knit" or "dangling loop + loose loop + plain knit".

4. The weft-knitted fabric according to claim 1, characterized in that, The heat and moisture responsive yarn has an axial elongation of 15%-40% after moisture absorption.

5. The weft-knitted fabric according to claim 1, characterized in that, The base yarn (2) is selected from one or more of polyester, spandex, polypropylene and their blended yarns; the heat and moisture responsive yarn is selected from one or more of heat and moisture elongation polyester, heat and moisture elongation nylon, heat and moisture elongation wool yarn, or is a parallel or core-sheath composite yarn composed of at least two components with different radial heat and moisture expansion coefficients.

6. The weft-knitted fabric according to claim 1, characterized in that, The yarn (1) comprises a variety of heat and moisture responsive yarns with different elongation rates to form differentiated pore regulation responses.

7. The weft-knitted fabric according to claim 6, characterized in that, The fabric body includes at least a first functional zone (3) and a second functional zone (3); wherein the first functional zone (3) uses a first heat and moisture responsive yarn with an axial elongation of 15%-30% after moisture absorption; and the second functional zone (3) uses a second heat and moisture responsive yarn with an axial elongation of 30%-40% after moisture absorption.

8. The weft-knitted fabric according to any one of claims 1 to 7, characterized in that, The total content of the heat and moisture responsive yarn accounts for 50%-90% of the total mass of the weft-knitted fabric.

9. A method for preparing a weft-knitted fabric as described in any one of claims 1 to 8, characterized in that, Includes the following steps: S1. Select at least one heat-moisture responsive yarn as the face yarn (1), the heat-moisture responsive yarn has reversible moisture absorption and elongation characteristics, the axial elongation rate after moisture absorption is 15%-40%, and it can basically recover after drying; select at least one low moisture absorption yarn as the base yarn (2). S2. Using the weft knitting process, the face yarn (1) and the base yarn (2) are interwoven. The face yarn (1) is controlled to cover the front side of the fabric process throughout the process, and the base yarn (2) is exposed on the back side of the fabric process, forming a stable double-layer structure. S3. During the knitting process, according to the preset pattern program, in an area with a minimum weave cycle height of 6-32 rows and a pattern width of 4-36 stitches, the yarn (1) is controlled to be knitted in a local combination of "tuck + plain stitch", "float + plain stitch", "float + loose loop + plain stitch" or "hanging stitch + loose loop + plain stitch" to form a pore control unit (11) that presents a closed form in the dry state.

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