A highly resilient spacer knitted fabric

Abstract

The present invention relates to a high-resilience spacer knitted fabric, comprising a first planar knitted fabric layer and a second planar knitted fabric layer, the first and second planar knitted fabric layers being connected by interwoven spacer yarns. The spacer yarns are parallel thermoplastic polymer composite monofilaments. In any axial cross-section of the parallel thermoplastic polymer composite monofilaments, a first component system and a second component system are arranged on either side of the monofilaments. The first and second component systems of the parallel thermoplastic polymer composite monofilaments have a differential shrinkage rate, which is ≤15%. The diameter of the parallel thermoplastic polymer composite monofilaments is no less than 0.07 mm. The spacer yarns in the high-resilience spacer knitted fabric of the present invention are parallel thermoplastic polymer composite monofilaments, which enhances the durability of the spacer yarns and significantly improves the compression resilience of the spacer knitted fabric.

Description

Technical Field

[0001] The present invention belongs to the technical field of textile materials and relates to a high-elasticity spacer knitted fabric. Background Art

[0002] A spacer knitted fabric is a unique fabric, characterized in that two knitted layers are connected by upright spacer yarns, thus providing excellent support in the thickness direction; in addition, the fabric also has the advantages of light weight and breathability. These characteristics enable the spacer knitted fabric to be used as a cushioning material in the fields of medical and health (such as anti-decubitus mattresses, wheelchair cushions), sports protection (such as knee pads, elbow pads), home textiles (such as pillows, mattresses), transportation (such as automotive ventilation seat systems), etc. Although the spacer knitted fabric has obvious advantages in air permeability, moisture permeability, production efficiency and environmental friendliness, when facing product applications with extremely long service lives, it is still necessary to improve its compression resilience to meet the durability requirements.

[0003] The industry evaluates the durability of spacer knitted fabrics according to the standard of GB / T 18941-2003 "Determination of indentation fatigue under constant load for high polymer porous elastic materials", requiring that after the spacer knitted fabric undergoes 80,000 compression tests with an indenter of 750 ± 20 N, its thickness loss rate ≤ 8%, and the requirements for resilience are still increasing.

[0004] The compression resilience of the spacer knitted fabric is closely related to the compressive properties of the spacer yarn material and the structural stability of the spacer knitted fabric.

[0005] In order to improve the compression resilience, a variety of techniques and methods have been proposed. For example, patent application CN107938151A discloses a spacer knitted fabric using hollow monofilaments as spacer yarns. Compared with the traditional spacer knitted fabric using solid monofilaments as spacer yarns, its anti-compression performance per unit mass has been improved by 10% - 15%. The improvement of the anti-compression performance makes the spacer knitted fabric less likely to undergo plastic deformation when bearing weight, so its compression resilience is improved. However, the hollow monofilaments have the problem of cavity collapse and insufficient durability.

[0006] Patent application CN116761912A discloses a structural design method for enhancing the compressive resistance of spacer knitted fabrics. One knitted fabric layer has a mesh structure, while the other has a dense structure. Compared to spacer knitted fabrics with both knitted layers having a mesh structure, this design improves stability, helps prevent local collapse, suppresses lateral collapse of the spacer yarns under external pressure, and improves elastic recovery. The compressive stress at 40% strain is 5±2 kPa, and the air permeability is ≥3500 mm / s. Patent CN201480024003.7 discloses a method for reinforcing spacer knitted fabrics by partially melting thermoplastic polymer yarns within the knitted fabric layers, thereby enhancing the stability of the spacer yarns. When subjected to pressure, the spacer yarns collapse less. Similar patents for utilizing molten yarns to enhance the compression resistance of spacer fabrics include CN201580014945.1, DE102009013253A1, DE102006004914B4, and DE19931193C2. Through structural design and molten thermoplastic polymer yarn bonding methods, these spacer knitted fabrics achieve enhanced compression resistance and elastic limit, resulting in only small compressive strains under external forces, maintaining their elastic state. However, once the spacer knitted fabric experiences large compressive strains, the more strongly constrained the spacer yarns, the greater the stress concentration within the yarns, which must withstand greater internal stress to resist deformation, making the material susceptible to damage. Existing spacer knitted fabrics exhibit a minimum thickness loss rate of only 9-12% after 80,000 cycles of compression at a compressive strain of 70%, requiring further improvement. Furthermore, spacer knitted fabrics enhanced in compression performance through molten thermoplastic polymer yarn bonding experience a stiff feel, reduced comfort, and poor conformability.

[0007] Therefore, it is of great significance to study a high-resilience spacer knitted fabric to solve the problems existing in the prior art. Summary of the Invention

[0008] The purpose of the present invention is to solve the problems existing in the prior art and provide a high-resilience spacer knitted fabric.

[0009] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0010] A high-resilience spacer knitted fabric comprises a first planar knitted fabric layer and a second planar knitted fabric layer, wherein the first planar knitted fabric layer and the second planar knitted fabric layer are connected by woven spacer yarns, wherein the spacer yarns are parallel thermoplastic polymer composite monofilaments;

[0011] The first component system and the second component system of the parallel thermoplastic polymer composite monofilament are arranged on both sides of the monofilament in any cross section along the axial direction;

[0012] The first component system of the side-by-side thermoplastic polymer composite monofilament is polyethylene terephthalate (PET), and the second component system is one or more of polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT), and polyester thermoplastic elastomer (TPEE).

[0013] The diameter of the side-by-side thermoplastic polymer composite monofilament is not less than 0.07 mm.

[0014] As a preferred technical solution:

[0015] For a high-elasticity spacer knitted fabric as described above, the side-by-side thermoplastic polymer composite monofilament is obtained by separately extruding the first component system and the second component system through a twin-screw extruder, and after the two component systems converge, they are extruded from the same spinneret hole and then drawn.

[0016] For a high-elasticity spacer knitted fabric as described above, the first component system and the second component system of the side-by-side thermoplastic polymer composite monofilament have a shrinkage rate difference and the shrinkage rate difference ≤ 15%. When the shrinkage rate difference is too large, the two component systems of the side-by-side thermoplastic polymer composite monofilament are not firmly bonded, resulting in the separation of the two component systems. When the shrinkage rate difference is within the range of ≤ 6.8%, the side-by-side thermoplastic polymer composite monofilament does not have a helical crimp structure. When the shrinkage rate difference is within the range of 6.8 - 15%, the side-by-side thermoplastic polymer composite monofilament has a helical crimp structure. Whether it has a helical crimp structure or not, using the side-by-side thermoplastic polymer composite monofilament can improve the resilience of the spacer knitted fabric.

[0017] For a high-elasticity spacer knitted fabric as described above, the cross-sectional shape of the side-by-side thermoplastic polymer composite monofilament is circular, dumbbell-shaped, or gourd-shaped.

[0018] For a high-elasticity spacer knitted fabric as described above, the diameter of the side-by-side thermoplastic polymer composite monofilament is 0.07 - 5 mm.

[0019] Regarding the technology for preparing side-by-side thermoplastic polymer multifilaments, there have been many literatures and patents disclosed, such as the literatures (Factors affecting crimp configuration of PTT / PET bi-component filaments[J].Textile Research Journal, 2011, 81(5): 538–544) and (T400—New breakthrough of DuPont fiber[J].Jiangsu Textile, 2003, 1: 57–59), and patents CN201911350180.5, CN201911351589.9, CN201911351604.X, CN201711427472.5, etc. However, the fineness of such side-by-side thermoplastic polymer multifilaments is 60 - 250 dtex, and the fineness of a single fiber in the multifilament is 2 - 3 dtex. The fineness of a single fiber is much smaller than that of the large-diameter monofilaments used for spacer knitted fabrics.

[0020] Regarding the technology for preparing side-by-side polymer composite monofilaments, for example, the literature (Facile and large-scalefabrication of self-crimping elastic fibers for large strain sensors[J].Chinese Journal of Polymer Science, 2021, 39: 914–924.) prepared side-by-side composite monofilaments of TPEE / PET with a diameter of 0.035 mm, which are small-diameter monofilaments and not suitable for use as spacer yarns for spacer knitted fabrics. The literature (Evolution of interfacial formation and configuration control of bicomponentfiber during full spinning process[J]. Textile Research Journal, 2023, 93(3–4): 971–982) showed side-by-side composite monofilaments of low-viscosity PET / high-viscosity PET extruded from a spinneret hole with a diameter of 0.35 mm, but the spinning process was incomplete. Only the nascent filaments were obtained by extrusion from the same spinneret hole after the confluence of the two-component system, and the finished filaments were not obtained through drawing. Therefore, the prior art has not disclosed a preparation method for large-diameter side-by-side polymer composite monofilaments that can be used as spacer yarns for spacer knitted fabrics.

[0021] The monofilaments used as spacer yarns for spacer knitted fabrics in this invention have a diameter of 0.07 mm to 5 mm, making them large-diameter monofilaments. The production process differs from existing parallel multifilament and small-diameter monofilament production methods. After melt extrusion, the yarn is cooled and solidified in an air-water bath, followed by heat drawing and heat setting. The spinning speed is much lower than that of multifilament and small-diameter monofilament production processes.

[0022] In the high-resilience spacer knitted fabric as described above, the first planar knitted fabric layer and the second planar knitted fabric layer are independently made of one or more of polyester, nylon and polypropylene.

[0023] In the high-resilience spacer knitted fabric as described above, the first planar knitted fabric layer and the second planar knitted fabric layer independently adopt a dense structure, a mesh structure or a patterned structure.

[0024] The high-resilience spacer knitted fabric as described above is knitted by double-needle-bed warp knitting or double-sided weft knitting.

[0025] A high-resilience spacer knitted fabric as described above, wherein the thickness of the high-resilience spacer knitted fabric is 1 to 40 mm;

[0026] After the high-resilience spacer knitted fabric is cyclically compressed 80,000 times at a compression strain of 70%, the thickness loss rate thereof is 3-5%.

[0027] The principles of the present invention are as follows:

[0028] Research has shown that when spacer knitted fabrics are compressed, any cross-section of the spacer yarn exhibits a tension-compression differentiation phenomenon, with one side stretched and the other compressed. Rigid PET monofilaments exhibit significantly insufficient compression resilience above 5%. When spacer knitted fabrics using PET monofilaments as spacer yarns experience high compressive strains (>26.5%), the material on the compressed side of the PET monofilaments easily reaches plastic strain or even limit strain, leading to elastic failure or even material destruction. Therefore, by improving existing PET spacer yarn materials and using polymer materials with excellent compression resilience on the compressed side of the spacer yarns, the compression resilience of spacer knitted fabrics can be improved.

[0029] The principle of the present invention is specifically described by taking a large-diameter side-by-side thermoplastic polymer composite monofilament in which the first component system is polyethylene terephthalate (PET) and the second component system is polybutylene terephthalate (PBT) as an example.

[0030] The molecular chain of PET generally exhibits higher rigidity and high tensile strength, while the molecular chain of PBT is a folded chain with good compression resilience.

[0031] When the shrinkage rate difference between the first component system PET and the second component system PBT is small, the monofilament has no special helical crimp structure. According to the principle of minimum energy in physics, the system always tends to reach the state with the lowest energy. The side-by-side composite monofilament will automatically adjust its configuration to optimally distribute the tensile and compressive stresses on both sides of the monofilament to adapt to the tensile and compressive differentiation phenomenon of one side being stretched and the other side being compressed in the spacer yarn: the first component system PET with high tensile strength bears the tensile strain, and the second component system PBT with good compression resilience bears the compressive strain. The two-component system gives full play to their respective mechanical property advantages, and the material is not easy to reach plastic strain or even ultimate strain, enhancing the durability of the spacer yarn and improving the compression resilience of the spacer knitted fabric.

[0032] When the shrinkage rate difference between the first component system PET and the second component system PBT is large, the monofilament can exhibit a helical crimp structure. The LYCRA® T400® PTT / PET and LYCRA® T800® PBT / PET side-by-side multifilaments utilize this helical crimp structure to enhance the tensile resilience of the yarn. Compared with the spacer yarn without a helical crimp structure, the helical crimp spacer yarn exhibits excellent compression resilience. When the spacer knitted fabric undergoes large compressive strain, the helical crimp structure undergoes significant global deformation, the spacing of the helical coils decreases, while the stress borne by the spacer yarn body remains at a low level, only producing slight torsion, and the mechanical behavior of the material still remains in the elastic range. This deformation mode effectively disperses the stress, avoids stress concentration, and improves the compression resilience of the spacer knitted fabric.

[0033] Beneficial effects:

[0034] In a high-resilience spacer knitted fabric of the present invention, the spacer yarn is a side-by-side thermoplastic polymer composite monofilament with a diameter of 0.07 to 5 mm. The spacer yarn has excellent durability, and the compression resilience of the spacer knitted fabric is significantly better than that of the prior art. Brief description of the drawings

[0035] Figure 1 It is a schematic diagram of the uncompressed high-resilience spacer knitted fabric without a helical crimp structure of the present invention;

[0036] Figure 2 It is a schematic diagram of the uncompressed high-resilience spacer knitted fabric with a helical crimp structure of the present invention;

[0037] Among them, 1 - the first planar knitted fabric layer, 2 - the second planar knitted fabric layer, 3 - the spacer yarn. Detailed implementation manners

[0038] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of this application.

[0039] The test methods related to the performance indicators of the present invention are as follows:

[0040] (1) Compressive stress value: According to the EN ISO 3386-1 standard, the size of the spacer knitted fabric specimen is 100 mm×100 mm, the compression speed is 100 mm / min, the compression depth is 70% of the initial thickness of the specimen, and the compression performance of the spacer knitted fabric is evaluated by the stress value at 40% strain. Each example and comparative example are repeated 5 times.

[0041] (2) Thickness loss rate: Referring to the EN ISO 3386-1 standard, the size of the spacer knitted fabric specimen is 100 mm×100 mm, the compression speed is 100 mm / min, the compression depth is 70% of the initial thickness of the specimen, and after compression, the specimen is decompressed at the same rate; referring to the GB / T 18941-2003 "Determination of constant load impact fatigue of high polymer porous elastic materials" standard, the number of cyclic compressions is 80,000 times. According to the evaluation index of durability, the resilience of the spacer knitted fabric is evaluated by the thickness loss rate. Each example and comparative example are repeated 5 times.

[0042] (3) Shrinkage rate: The shrinkage rates of the two-component systems of the side-by-side thermoplastic polymer composite monofilaments cannot be directly experimentally determined, and only the difference can be estimated through theoretical formulas. This difference is approximately estimated based on the relationship in the literature (The crimp curvature of bicomponent fibers[J]. Journal of Textile Institute, 1981, 73(6): 253–263) from the cross-sectional shape and longitudinal crimp structure of the side-by-side composite monofilament. The relationship is as follows:

[0043] For side-by-side thermoplastic polymer composite monofilaments with a circular cross-sectional shape:

[0044] ;

[0045] Among them, is the crimp curvature; is the crimp curvature radius; is the shrinkage rate difference of the two-component system; is the radius; is the distance from the interface of the two-component system to the center of the circle and the radius The ratio, namely .

[0046] For the side-by-side type thermoplastic polymer composite monofilaments with a dumbbell-shaped or gourd-shaped cross-section:

[0047] ;

[0048] Among them, is the crimp curvature; is the crimp curvature radius; is the shrinkage rate difference of the two-component system; the dumbbell shape and the gourd shape can be approximated as two overlapping circles, is the radius of the circle; is the distance from the interface of the two-component system to the center of the circle The ratio with the radius , namely .

[0049] The crimp curvature can be approximately estimated by testing the geometric configuration of the side-by-side type thermoplastic polymer composite monofilament with a standard three-dimensional helical curve. The relationship is as follows:

[0050] ;

[0051] Among them, is the radius of the cylindrical surface where the three-dimensional helical curve is located; is the length of the cylinder where a complete helix is located, namely the pitch.

[0052] It should be noted that this method is only applicable to calculating the shrinkage rate difference of the two-component system of the side-by-side type thermoplastic polymer composite monofilament with a helical crimp structure. For the side-by-side type thermoplastic polymer composite monofilament without a helical crimp structure, the shrinkage rate difference cannot be given. Since the shrinkage rate difference is the fundamental reason for determining whether there is a helical crimp structure, a small shrinkage rate difference means no helical crimp configuration. Therefore, based on the minimum shrinkage rate difference (6.8%) of the side-by-side composite monofilament with a helical crimp structure in the examples, 6.8% is set as the critical shrinkage rate for the presence or absence of a helical crimp configuration.

[0053] Example 1

[0054] A highly resilient spacer knitted fabric, as Figure 1 shown, includes a first planar knitted fabric layer 1 and a second planar knitted fabric layer 2;

[0055] The first planar knitted fabric layer 1 and the second planar knitted fabric layer 2 are connected by the woven spacer yarn 3. The spacer yarn 3 is a side-by-side type thermoplastic polymer composite monofilament without a helical crimp structure;

[0056] Both the first planar knitted fabric layer 1 and the second planar knitted fabric layer 2 are made of 600D / 192F polyester multifilament and are both in a mesh structure;

[0057] The preparation process of the side-by-side thermoplastic polymer composite monofilament is as follows: The first component system and the second component system are respectively extruded through a twin-screw extruder. The first component system is polyethylene terephthalate (PET) with an intrinsic viscosity of 1.03 dL / g (China National Petroleum and Chemical Corporation); the second component system is polybutylene terephthalate (PBT) with an intrinsic viscosity of 1.26 dL / g (Suzhou Baolidi Material Technology Co., Ltd.). The volume ratio of the two component systems is 50:50. After the two component systems converge, they are extruded from the same spinneret hole, pass through an air layer (5 cm), and then enter a coagulation water bath (70 °C), and then successively pass through hot water stretching (90 °C), hot air stretching (180 °C), and heat setting (235 °C, 1.8 s). Tension rollers are equipped before and after each of the hot water stretching, hot air stretching, and heat setting processes, with a total of four tension rollers, and finally wound onto a winding machine;

[0058] The process parameters are as follows: The extrusion speed of the melt from the spinneret hole is 3.8 m / min, the first stretching speed is 28.8 m / min, the second stretching speed is 100 m / min, the third stretching speed is 126 m / min, the fourth stretching speed is 120 m / min, the overfeed ratio F = 4.76%, and the winding speed is 118 m / min;

[0059] In any cross-section along the axial direction of the side-by-side thermoplastic polymer composite monofilament, the first component system and the second component system are arranged on both sides of the monofilament; the cross-sectional shape of the side-by-side thermoplastic polymer composite monofilament is circular with a diameter of 0.25 mm;

[0060] The high-resilience spacer knitted fabric is woven by double needle bed warp knitting method. The double needle bed warp knitting machine is E12. The warp knitting machine is equipped with six guide bars (GB1~GB6). GB2 and GB5 are fully threaded with 600D / 192F polyester multifilament respectively, and each is knitted on the front and back needle beds to form a chain structure. The yarn numbers are: GB2: (1-0-0-0 / 0-1-1-1)×5 / / , GB5: (1-1-1-0 / 0-0-0-1)×5 / / ; GB1 and GB6 are threaded in one thread and one empty thread, and 600D / 192F polyester multifilament is threaded in one thread. D / 192F polyester multifilament yarn is weft-inserted on the front and rear needle beds, respectively. The inlay yarn numbers for GB1 and GB6 are both (2-2-2-2 / 0-0-0-0) × 2 / 2-2-2-2 / (1-1-1-1 / 3-3-3-3) × 2 / 1-1-1-1 / / . GB3 is a fully threaded parallel thermoplastic polymer composite monofilament yarn. The yarns are alternately inlaid on the front and rear needle beds to form a chain weave, connecting the first and second knitted fabric layers. The inlay yarn numbers are (1-0-1-0 / 0-1-0-1) × 5 / / .

[0061] The high-resilience spacer knitted fabric has a thickness of 10.2±0.22mm, a longitudinal density of 6.7±0.19 rows / cm, a transverse density of 2.76±0.09 wales / cm, and a gram weight of 530±6.75g / m 2 The compression stress value is 7±2kPa. After 80,000 cycles of compression at a compression strain of 70%, the thickness loss rate of the high-rebound spacer knitted fabric is 4.0±0.3%.

[0062] Comparative Example 1

[0063] A spacer knitted fabric is basically the same as Example 1, except that the spacer yarn of the spacer knitted fabric adopts 0.25 mm PET monofilament processed and produced by the JSDW45-28 large-diameter monofilament production line of Shanghai Duwei Chemical Fiber Co., Ltd.

[0064] The thickness of the spacer knitted fabric is 10.5±0.18mm, the vertical density is 5.5±0.15 rows / cm, the horizontal density is 2±0.03 wales / cm, and the gram weight is 533±5.57g / m 2 The compression stress value is 8±0.5kPa. After 80,000 cycles of compression under a compression strain of 70%, the thickness loss rate of the high-rebound spacer knitted fabric is 10.7±0.3%.

[0065] Comparing Comparative Example 1 with Example 1, the support of Comparative Example 1 is improved, but its resilience is significantly reduced. This is because PET has high rigidity but insufficient compression resilience. During cyclic compression, the PET monofilament undergoes tension and compression differentiation along the length direction, and the material on the compressed side is prone to plastic strain, causing elastic failure, so its resilience is insufficient.

[0066] Example 2

[0067] A high-resilience spacer knitted fabric comprises a first planar knitted fabric layer and a second planar knitted fabric layer;

[0068] The first planar knitted fabric layer and the second planar knitted fabric layer are connected by woven spacer yarns, wherein the spacer yarns are parallel thermoplastic polymer composite monofilaments without a spiral curling structure;

[0069] The first knitted fabric layer and the second knitted fabric layer are both made of 600D / 192F polyester multifilament and have a mesh structure;

[0070] The parallel thermoplastic polymer composite monofilament was prepared by extruding a first component system and a second component system separately through a twin-screw extruder. The first component system was polyethylene terephthalate (PET) with an intrinsic viscosity of 1.03 dL / g (Sinopec Group Co., Ltd.). The second component system was a mixture of polyethylene terephthalate (PET) and polybutylene terephthalate (PBT) in a mass ratio of 30:70. The intrinsic viscosity of the PET in the second component system was 1.03 dL / g (Sinopec Group Co., Ltd.). The intrinsic viscosity of PBT in the second component system is 1.26 dL / g (Suzhou Polydi Materials Technology Co., Ltd.); the volume ratio of the two components is 25:75; after the two components are combined, they are extruded from the same spinneret, pass through a 5 cm air layer, and then enter a coagulation water bath (70°C). They are then sequentially stretched by hot water (90°C), stretched by hot air (180°C), and heat-set (235°C, 1.8 seconds). Each step is preceded and followed by stretching rollers, for a total of four stretching rollers, before being wound onto a winder.

[0071] The process parameters are as follows: melt extrusion speed from spinneret The stretching speed is 3.8m / min. The second stretching speed is 28.8m / min The three-pass stretching speed is 100m / min The four-pass stretching speed is 126m / min The speed is 120m / min, the overfeed rate F=4.76%, and the winding speed is 118m / min;

[0072] The parallel type thermoplastic polymer composite monofilament has a first component system and a second component system arranged on both sides of the monofilament in any cross section along its axial direction; the cross section of the parallel type thermoplastic polymer composite monofilament is circular with a diameter of 0.25 mm;

[0073] The high-resilience spacer knitted fabric is woven by double needle bed warp knitting method. The double needle bed warp knitting machine is E12. The warp knitting machine is equipped with six guide bars (GB1~GB6). GB2 and GB5 are fully threaded with 600D / 192F polyester multifilament respectively, and each is knitted on the front and back needle beds to form a chain structure. The yarn numbers are: GB2: (1-0-0-0 / 0-1-1-1)×5 / / , GB5: (1-1-1-0 / 0-0-0-1)×5 / / ; GB1 and GB6 are threaded in one thread and one empty thread, and 600D / 192F polyester multifilament is threaded in one thread. D / 192F polyester multifilament yarn is weft-inserted on the front and rear needle beds, respectively. The inlay yarn numbers for GB1 and GB6 are both (2-2-2-2 / 0-0-0-0) × 2 / 2-2-2-2 / (1-1-1-1 / 3-3-3-3) × 2 / 1-1-1-1 / / . GB3 is a fully threaded parallel thermoplastic polymer composite monofilament yarn. The yarns are alternately inlaid on the front and rear needle beds to form a chain weave, connecting the first and second knitted fabric layers. The inlay yarn numbers are (1-0-1-0 / 0-1-0-1) × 5 / / .

[0074] The thickness of the high-rebound spacer knitted fabric is 9.56±0.06mm, the vertical density is 5.89±0.23 rows / cm, the horizontal density is 2.54±0.07 wales / cm, and the gram weight is 528±7.61g / m 2 ; After 80,000 cycles of compression of high-rebound spacer knitted fabric with a compressive stress value of 6.5±1.5kPa and a compressive strain of 70%, its thickness loss rate is 3.8±0.2%.

[0075] Example 3

[0076] A high-resilience spacer knitted fabric comprises a first planar knitted fabric layer and a second planar knitted fabric layer;

[0077] The first planar knitted fabric layer and the second planar knitted fabric layer are connected by woven spacer yarns, wherein the spacer yarns are parallel thermoplastic polymer composite monofilaments having a spiral curling structure;

[0078] The first knitted fabric layer and the second knitted fabric layer are both made of 600D / 192F polyester multifilament and have a mesh structure;

[0079] The preparation process of the side-by-side thermoplastic polymer composite monofilament is as follows: The first component system and the second component system are respectively extruded through a twin-screw extruder. The first component system is polyethylene terephthalate (PET) with an intrinsic viscosity of 1.03 dL / g (China National Petroleum and Chemical Corporation); the second component system is polyethylene terephthalate (PET) with an intrinsic viscosity of 0.67 dL / g (China National Petroleum and Chemical Corporation), and the volume ratio of the two component systems is 50:50. After the two component systems converge, they are extruded from the same spinneret hole, pass through an air layer (5 cm) and then enter a coagulation water bath (70 °C), and then successively go through hot water drawing (90 °C), hot air drawing (180 °C) and heat setting (235 °C, 1.8 s). Drawing rollers are equipped before and after each process of hot water drawing, hot air drawing and heat setting, with a total of four drawing rollers, and finally wound onto a winding machine;

[0080] The process parameters are as follows: The extrusion speed of the melt from the spinneret hole is 3.8 m / min, the first drawing speed is 28.8 m / min, the second drawing speed is 110 m / min, the third drawing speed is 130 m / min, the fourth drawing speed is 135 m / min, the overfeed rate F = -3.84%, and the winding speed is 130 m / min;

[0081] In any axial cross-section of the side-by-side thermoplastic polymer composite monofilament, the first component system and the second component system are arranged on both sides of the monofilament; the cross-sectional shape of the side-by-side thermoplastic polymer composite monofilament is circular with a diameter of 0.25 mm; the curvature radius of the side-by-side thermoplastic polymer composite monofilament is 1.19 mm; the shrinkage rate difference of the side-by-side thermoplastic polymer composite monofilament is 12.28%;

[0082] The high-resilience spacer knitted fabric is woven by double needle bed warp knitting method. The double needle bed warp knitting machine is E12. The warp knitting machine is equipped with six guide bars (GB1~GB6). GB2 and GB5 are fully threaded with 600D / 192F polyester multifilament respectively, and each is knitted on the front and back needle beds to form a chain structure. The yarn numbers are: GB2: (1-0-0-0 / 0-1-1-1)×5 / / , GB5: (1-1-1-0 / 0-0-0-1)×5 / / ; GB1 and GB6 are threaded in one thread and one empty thread, and 600D / 192F polyester multifilament is threaded in one thread. D / 192F polyester multifilament yarn is weft-inserted on the front and rear needle beds, respectively. The inlay yarn numbers for GB1 and GB6 are both (2-2-2-2 / 0-0-0-0) × 2 / 2-2-2-2 / (1-1-1-1 / 3-3-3-3) × 2 / 1-1-1-1 / / . GB3 is a fully threaded parallel thermoplastic polymer composite monofilament yarn. The yarns are alternately inlaid on the front and rear needle beds to form a chain weave, connecting the first and second knitted fabric layers. The inlay yarn numbers are (1-0-1-0 / 0-1-0-1) × 5 / / .

[0083] The thickness of the high-rebound spacer knitted fabric is 9.86±0.23mm, the vertical density is 5.66±0.13 rows / cm, the horizontal density is 2.33±0.01 wales / cm, and the gram weight is 545±4.71g / m 2 The compression stress value is 5.4±1.2kPa. After 80,000 cycles of compression at a compression strain of 70%, the thickness loss rate of the high-rebound spacer knitted fabric is 3.6±0.13%.

[0084] Example 4

[0085] A high-rebound spacer knitted fabric, such as Figure 2 As shown, it comprises a first planar knitted fabric layer 1 and a second planar knitted fabric layer 2;

[0086] The first planar knitted fabric layer 1 and the second planar knitted fabric layer 2 are connected by woven spacer yarns 3, wherein the spacer yarns 3 are parallel thermoplastic polymer composite monofilaments having a spiral curling structure;

[0087] The first planar knitted fabric layer 1 and the second planar knitted fabric layer 2 are both made of 300D / 96F polyester multifilament yarn, and both have a dense structure;

[0088] The preparation process of the parallel thermoplastic polymer composite monofilament is as follows: a first component system and a second component system are extruded separately through a twin-screw extruder; the first component system is polyethylene terephthalate (PET) with an intrinsic viscosity of 1.03 dL / g (China Petrochemical Corporation); the second component system is polytrimethylene terephthalate (PTT) with an intrinsic viscosity of 1.05 dL / g (Zhejiang Hengyi Petrochemical Research Institute Co., Ltd.); the volume ratio of the two components is 60:40; after the two components are combined, they are extruded from the same spinneret, pass through an air layer (5 cm), and then enter a coagulation water bath (70°C), and then undergo hot water stretching (90°C), hot air stretching (180°C), and heat setting (235°C, 1.8 seconds) in sequence. Each process of hot water stretching, hot air stretching, and heat setting is equipped with stretching rollers before and after, for a total of four stretching rollers, and finally wound onto a winder;

[0089] The process parameters are as follows: melt extrusion speed from spinneret The stretching speed is 3.8m / min. The second stretching speed is 28.8m / min The three-pass stretching speed is 120m / min 130m / min, four-pass stretching speed The speed is 135m / min, the overfeed rate F=-3.84%, and the winding speed is 130m / min;

[0090] The parallel type thermoplastic polymer composite monofilament has a first component system and a second component system arranged on both sides of the monofilament in any cross section along its axial direction; the cross section of the parallel type thermoplastic polymer composite monofilament is circular with a diameter of 0.25 mm; the curvature radius of the parallel type thermoplastic polymer composite monofilament is The shrinkage difference of the parallel thermoplastic polymer composite monofilament is 13.54%.

[0091] The high-resilience spacer knitted fabric is knitted by the double-needle-bed warp knitting method, and the machine number of the double-needle-bed warp knitting machine is E12; the warp knitting machine is equipped with six guide bars (GB1~GB6). GB1 and GB2 are fully threaded with 300D / 96F polyester multifilament to knit the first planar knitted fabric layer, and the guide bar digital patterns are respectively: GB1: 1-0-0-0 / 3-2-3-3 / / , GB2: 2-1-1-1 / 1-0-0-0 / / ; GB5 and GB6 are fully threaded with 300D / 96F polyester multifilament to knit the second planar knitted fabric layer, and the guide bar digital patterns are respectively: GB5: 0-0-2-1 / 1-1-1-0 / / , GB6: 3-3-1-0 / 0-0-3-2 / / ; GB3 and GB4 are threaded in a one-in-one-out manner with side-by-side composite monofilaments, and are alternately laid in the front and back needle beds to connect the first planar knitted fabric layer and the second planar knitted fabric layer, and the guide bar digital patterns are respectively: GB3: 1-0-3-2 / 3-2-1-0 / / , GB4: 3-2-1-0 / 1-0-3-2 / / ;

[0092] The thickness of the high-resilience spacer knitted fabric is 7.32±0.13mm, the wale density is 8.28±0.17 courses / cm, the course density is 5.96±0.07 wales / cm, and the gram weight is 1060±4.13g / m 2 ; the compression stress value is 4.5±0.5kPa; after the high-resilience spacer knitted fabric is cyclically compressed 80,000 times under a compression strain of 70%, its thickness loss rate is 3.2±0.11%.

[0093] Example 5

[0094] A high-resilience spacer knitted fabric, comprising a first planar knitted fabric layer and a second planar knitted fabric layer,

[0095] The first planar knitted fabric layer and the second planar knitted fabric layer are connected by woven spacer yarns. The spacer yarns are side-by-side thermoplastic polymer composite monofilaments with a helical crimp structure;

[0096] Both the first planar knitted fabric layer and the second planar knitted fabric layer are made of spandex (210D) wrapped with double-layer polyester (100D), and both are dense structures;

[0097] The preparation process of the side-by-side thermoplastic polymer composite monofilament is as follows: The first component system and the second component system are respectively extruded through a twin-screw extruder; the first component system is polyethylene terephthalate (PET) with an intrinsic viscosity of 1.03 dL / g (China National Petroleum and Chemical Corporation); the second component system is a thermoplastic polyester elastomer (TPEE) with an intrinsic viscosity of 1.69 dL / g (Shanghai Yidan New Materials Co., Ltd.); the volume ratio of the two component systems is 97:3; after the two component systems converge, they are extruded from the same spinneret hole, pass through an air layer (5 cm) and then enter a coagulation water bath (70 °C), and then successively undergo hot water drawing (90 °C), hot air drawing (180 °C) and heat setting (235 °C, 1.8 s). Drawing rollers are equipped before and after each of the hot water drawing, hot air drawing and heat setting processes, with a total of four drawing rollers, and finally wound onto a winding machine;

[0098] The process parameters are as follows: The extrusion speed of the melt from the spinneret hole is 3.8 m / min, the first drawing speed is 32.9 m / min, the second drawing speed is 148 m / min, the third drawing speed is 194 m / min, the fourth drawing speed is 180 m / min, the overfeed ratio F = 7.22%, and the winding speed is 178 m / min;

[0099] In any axial cross-section of the side-by-side thermoplastic polymer composite monofilament, the first component system and the second component system are arranged on both sides of the monofilament; the cross-sectional shape of the side-by-side thermoplastic polymer composite monofilament is circular with a diameter of 0.12 mm; the curvature radius of the side-by-side thermoplastic polymer composite monofilament is 0.93 mm; the shrinkage rate difference of the side-by-side thermoplastic polymer composite monofilament is 6.8%.

[0100] The high-elasticity spacer knitted fabric is knitted by a double-sided weft knitting method; the spacer yarns alternately form loops in the first sheet-like knitted fabric layer and the second sheet-like knitted fabric layer to connect the two knitted fabric layers. The loop-forming positions in the first sheet-like knitted fabric layer and the second sheet-like knitted fabric layer are separated by 4 stitches, and it is knitted on a computerized flat knitting machine with E7.2;

[0101] The thickness of the high-elasticity spacer knitted fabric is 4.46 ± 0.09 mm, the wale density is 18.03 ± 0.33 courses / cm, the course density is 6.87 ± 0.05 wales / cm, and the gram weight is 810 ± 5.68 g / m 2 ; the compression stress value is 4.0 ± 0.7 kPa; after the high-elasticity spacer knitted fabric is cyclically compressed 80,000 times at a compression strain of 70%, its thickness loss rate is 4.2 ± 0.5%.

[0102] Example 6

[0103] A high-resilience spacer knitted fabric comprises a first planar knitted fabric layer and a second planar knitted fabric layer.

[0104] The first planar knitted fabric layer and the second planar knitted fabric layer are connected by woven spacer yarns, wherein the spacer yarns are parallel thermoplastic polymer composite monofilaments without a spiral curling structure;

[0105] The first knitted fabric layer is made of 110D / 36F polyester with a dense structure; the second knitted fabric layer is made of 110D / 48F nylon with a patterned structure;

[0106] The parallel thermoplastic polymer composite monofilament is extruded through a twin-screw extruder to extrude a first component system and a second component system respectively; the first component system is polyethylene terephthalate (PET) with an intrinsic viscosity of 1.03 dL / g (China Petrochemical Corporation); the second component system is polytrimethylene terephthalate (PTT) with an intrinsic viscosity of 1.05 dL / g (Zhejiang Hengyi Petrochemical Research Institute Co., Ltd.); the volume ratio of the two component systems is 95:5; after the two component systems are merged, they are extruded from the same spinneret, pass through an air layer (5 cm), and then enter a coagulation water bath (70°C), and then undergo hot water stretching (90°C), hot air stretching (180°C), and heat setting (235°C, 1.8s) in sequence. Each process of hot water stretching, hot air stretching, and heat setting is equipped with stretching rollers before and after, for a total of four stretching rollers, and is finally wound onto a winder;

[0107] The process parameters are as follows: melt extrusion speed from spinneret The stretching speed is 3.8m / min. The second stretching speed is 44.5m / min The three-pass stretching speed is 180m / min 240m / min, four-pass stretching speed The speed is 200m / min, the overfeed rate F=16.67%, and the winding speed is 198m / min;

[0108] The parallel type thermoplastic polymer composite monofilament has a first component system and a second component system arranged on both sides of the monofilament in any cross section along its axial direction; the cross section of the parallel type thermoplastic polymer composite monofilament is circular with a diameter of 0.08 mm;

[0109] The high-resilience spacer knitted fabric is knitted using a double-sided weft knitting method. The spacer yarn is alternately tucked between the first and second knitted layers to connect the two knitted layers. The spacer yarn is alternately tucked between the first and second knitted layers to connect the two knitted layers. The tuck positions of the first and second knitted layers are spaced one stitch apart. The fabric is knitted on an E28 double-sided circular knitting machine.

[0110] The high-rebound spacer knitted fabric has a thickness of 1.82±0.03 mm, a longitudinal density of 35.2±2.4 rows / cm, a transverse density of 20.4±3.6 wales / cm, and a grammage of 300±2.5g / m 2 The compression stress value is 0.92±0.4kPa. After 80,000 cycles of compression at a compression strain of 70%, the thickness loss rate of the high-rebound spacer knitted fabric is 1.9±0.1%.

[0111] Comparative Example 2

[0112] A spacer knitted fabric is basically the same as Example 6, except that the diameter of the parallel thermoplastic polymer composite monofilament is 0.06 mm and there is no spiral curling structure.

[0113] The thickness of the spacer knitted fabric is 1.72±0.01 mm, the vertical density is 37.2±2.2 rows / cm, the horizontal density is 22.4±3.3 wales / cm, and the gram weight is 295±2.3g / m 2 The compression stress value is 0.72±0.2kPa. After 80,000 cycles of compression at a compression strain of 70%, the thickness loss rate of the high-rebound spacer knitted fabric is 1.7±0.1%.

[0114] Comparing Comparative Example 2 with Example 6, it can be found that the elasticity of the spacer knitted fabric in Comparative Example 2 is improved, but its support is significantly reduced. This is because according to the formula of the moment of inertia of the circular cross section ,in is the cross-sectional radius, and the reduction in the moment of inertia reduces the bending stiffness of the spacer yarn in Comparative Example 2 (the bending stiffness is proportional to the moment of inertia I and the elastic modulus E); in Comparative Example 2, the support of the spacer knitted fabric with a diameter of 0.06 mm is greatly reduced, and the basic performance of the spacer knitted fabric cannot be maintained, and good support cannot be provided.

Claims

1. A high resilience spacer knitted fabric, comprising a first planar knitted fabric layer and a second planar knitted fabric layer, wherein the first planar knitted fabric layer and the second planar knitted fabric layer are connected by woven spacer yarns, and is characterized in that: The spaced yarn is a side-by-side type thermoplastic polymer composite monofilament; In any axial cross-section of the side-by-side type thermoplastic polymer composite monofilament, the first component system and the second component system are arranged on both sides of the monofilament; The first component system of the side-by-side type thermoplastic polymer composite monofilament is polyethylene terephthalate, and the second component system is one or more of polyethylene terephthalate, polybutylene terephthalate, polypropylene terephthalate, and polyester thermoplastic elastomer; The first component system and the second component system of the side-by-side type thermoplastic polymer composite monofilament have a shrinkage rate difference, and the shrinkage rate difference is 6.8-15%, and the side-by-side type thermoplastic polymer composite monofilament has a spiral crimp structure; The diameter of the side-by-side type thermoplastic polymer composite monofilament is 0.07-5 mm; The thickness of the highly elastic spacer knitted fabric is 1-40 mm; After the highly elastic spacer knitted fabric is cyclically compressed 80,000 times under a compressive strain of 70%, its thickness loss rate is 3-5%; 2. The high-resilience spacer knitted fabric according to claim 1, wherein, The side-by-side type thermoplastic polymer composite monofilament is prepared by separately extruding the first component system and the second component system through a twin-screw extruder, and after the two component systems converge, they are extruded from the same spinneret hole and then drawn; 3. The high-resilience spacer knitted fabric according to claim 1 or 2, characterized in that, The cross-sectional shape of the side-by-side type thermoplastic polymer composite monofilament is circular, dumbbell-shaped or gourd-shaped; 4. A highly resilient spacer knitted fabric according to claim 1 or 2, characterized in that, The first planar knitted fabric layer and the second planar knitted fabric layer are each independently made of one or more of polyester, nylon, and polypropylene; 5. A highly resilient spacer knitted fabric according to claim 1 or 2, characterized in that, The first planar knitted fabric layer and the second planar knitted fabric layer are each independently made of a dense structure, a mesh structure or a fancy structure; 6. A highly resilient spacer knitted fabric according to claim 1 or 2, characterized in that, The highly elastic spacer knitted fabric is knitted by a double needle bed warp knitting or double-sided weft knitting method.

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