High-resilience interval knitted fabric

Abstract

The invention relates to a high-resilience interval knitted fabric which comprises a first planar knitted fabric layer and a second planar knitted fabric layer, the first planar knitted fabric layer and the second planar knitted fabric layer are connected through woven interval yarns, and the interval yarns are parallel thermoplastic polymer composite monofilaments; the first component system and the second component system in any axial section of the parallel thermoplastic polymer composite monofilament are respectively arranged on two sides of the monofilament; the first component system and the second component system of the parallel thermoplastic polymer composite monofilament have shrinkage rate difference, and the shrinkage rate difference value is less than or equal to 15%; and the diameter of the parallel thermoplastic polymer composite monofilament is not less than 0.07 mm. The spacer yarns in the high-resilience spacer knitted fabric adopt the parallel thermoplastic polymer composite monofilaments, so that the durability of the spacer yarns is enhanced, and the compression resilience of the spacer knitted fabric is greatly improved.

Description

Technical Field

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

[0002] Spacer knitted fabric is a unique fabric characterized by connecting two knitted layers through upright spacer yarns, which provides excellent support in the thickness direction; in addition, the fabric is lightweight and breathable. These characteristics make spacer knitted fabrics used as cushioning materials in medical and health care (such as anti-bedsore mattresses, wheelchair cushions), sports protection (such as knee pads, elbow pads), household textiles (such as pillows, mattresses), transportation (such as automotive ventilated seat systems) and other fields. Although spacer knitted fabrics have obvious advantages in air permeability, moisture permeability, production efficiency and environmental friendliness, when faced with product applications with extremely long service life, their compression resilience still needs to be improved to meet durability requirements.

[0003] The industry evaluates the durability of spacer knitted fabrics based on the standard GB / T 18941-2003 "Determination of Constant Load Impact Fatigue of Polymer Porous Elastic Materials", requiring that after 80,000 compression tests with a 750±20N indenter, the thickness loss rate of the spacer knitted fabric should be ≤8%, and the requirements for resilience are still increasing.

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

[0005] In order to improve the compression resilience, a variety of technologies 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 compression resistance per unit mass is improved by 10% to 15%. The improvement in compression resistance makes it less likely for the spacer knitted fabric to undergo plastic deformation when bearing load, thereby improving its compression resilience. However, hollow monofilaments have the problem of cavity collapse and lack durability.

[0006] Patent application CN116761912A discloses a structural design method for enhancing the compressive resistance of spacer knitted fabrics, wherein one knitted fabric layer is a mesh structure and the other knitted fabric layer is a dense structure. Compared with spacer knitted fabrics in which both knitted fabric layers are mesh structures, the stability is improved, which helps to avoid local collapse, inhibits the lateral lodging of the spacer yarn under external pressure, and improves elastic recovery; the compressive stress value is 5±2 kPa at 40% strain, and the air permeability is ≥3500 mm / s. Patent CN201480024003.7 discloses a method for reinforcing spacer knitted fabrics by melting part of thermoplastic polymer yarns in the knitted fabric layer, so that the stability of the spacer yarns is improved. When under pressure, the spacer yarns collapse less. Similar patents that use molten yarn 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, the compression resistance and elastic limit of spacer knitted fabrics are improved, so that they only produce small compression strains under external forces and maintain an elastic state. However, once the spacer knitted fabric experiences a large compression strain, the spacer yarns with stronger constraints will experience stress concentration, and they need to withstand greater internal stress to resist deformation, and the material is prone to damage. After the spacer knitted fabric of the prior art is compressed 80,000 times under a compression strain of 70%, the minimum thickness loss rate can only be within the range of 9~12%, which needs to be further improved. At the same time, the spacer knitted fabric with enhanced compression performance through molten thermoplastic polymer yarn bonding has a hard 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] 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, and 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 parallel 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 parallel thermoplastic polymer composite monofilament is not less than 0.07 mm.

[0014] As the preferred technical solution:

[0015] As described above, a high resilience spacer knitted fabric, the parallel thermoplastic polymer composite monofilament is obtained by respectively extruding a first component system and a second component system through a twin-screw extruder, and the two component systems are combined and extruded from the same spinneret hole and then stretched.

[0016] In the high-resilience spacer knitted fabric as described above, the first component system and the second component system of the parallel thermoplastic polymer composite monofilament have a difference in shrinkage rate and the difference in shrinkage rate is ≤15%. When the difference in shrinkage rate is too large, the two-component system of the parallel thermoplastic polymer composite monofilament is not firmly bonded, resulting in the separation of the two-component system. When the difference in shrinkage rate is within the range of ≤6.8%, the parallel thermoplastic polymer composite monofilament does not have a spiral curling structure, and when the difference in shrinkage rate is within the range of 6.8~15%, the parallel thermoplastic polymer composite monofilament has a spiral curling structure. Regardless of whether it has a spiral curling structure, the use of parallel thermoplastic polymer composite monofilaments can improve the resilience of the spacer knitted fabric.

[0017] In the high resilience spacer knitted fabric as described above, the cross-sectional shape of the parallel thermoplastic polymer composite monofilament is circular, dumbbell-shaped or gourd-shaped.

[0018] In the high-resilience spacer knitted fabric as described above, the diameter of the parallel thermoplastic polymer composite monofilament is 0.07-5 mm.

[0019] There are many documents and patents on the technology of preparing parallel thermoplastic polymer multifilaments, such as (Factors affecting crimp configuration of PTT / PET bi-component filaments[J].Textile Research Journal, 2011, 81(5): 538–544) and (T400—A new breakthrough in DuPont fiber[J].Jiangsu Textile, 2003, 1: 57–59), patents CN201911350180.5, CN201911351589.9, CN201911351604.X and CN201711427472.5, etc. However, the fineness of this type of parallel thermoplastic polymer multifilaments is 60~250dtex, and the fineness of a single fiber in the multifilament is 2~3dtex, which is much smaller than the large diameter monofilament used for spacer knitted fabrics.

[0020] Regarding the technology for preparing parallel polymer composite monofilaments, for example, the literature (Facile and large-scale fabrication of self-crimping elastic fibers for large strain sensors [J]. Chinese Journal of Polymer Science, 2021, 39: 914–924.) prepared TPEE / PET parallel composite monofilaments with a diameter of 0.035 mm, which are small-diameter monofilaments and are not suitable for use as spacer yarns for spacer knitted fabrics. The literature (Evolution of interfacial formation and configuration control of bicomponent fiber during full spinning process [J]. Textile Research Journal, 2023, 93 (3–4): 971–982) shows low-viscosity PET / high-viscosity PET parallel composite monofilaments extruded from a spinneret with a diameter of 0.35 mm, but the spinning process is incomplete, and only the two-component system is combined and extruded from the same spinneret to obtain the primary yarn, and the finished yarn is obtained without drawing. Therefore, the prior art has not yet disclosed a method for preparing large-diameter parallel polymer composite monofilaments that can be used as spacer yarns for spacer knitted fabrics.

[0021] The diameter of the monofilament used as the spacer yarn of the spacer knitted fabric in the present invention is 0.07 mm to 5 mm, which is a large diameter monofilament. The preparation process is different from the existing parallel multifilament and parallel small diameter monofilament. After the melt is extruded, it is cooled and solidified by air and water bath, and then hot drawing and heat setting process are carried out. The spinning speed is much lower than the multifilament and small diameter monofilament process.

[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 for 80,000 times at a compression strain of 70%, the thickness loss rate is 3-5%.

[0027] The principle of the present invention is as follows:

[0028] Studies have shown that when spacer knitted fabrics are compressed, any cross section of the spacer yarn shows a tension-compression differentiation phenomenon with one side stretched and the other side compressed. The compression resilience of rigid PET monofilaments is obviously insufficient when the strain is above 5%. For spacer knitted fabrics with PET monofilaments as spacer yarns, when the spacer knitted fabrics undergo large compression strain (>26.5%), the material on the compressed side of the PET monofilaments is prone to plastic strain or even limit strain, thereby causing elastic failure or even material damage. In view of this, by improving the existing PET spacer yarn materials and using polymer materials with excellent compression resilience properties on the compressed side of the spacer yarns, the compression resilience of spacer knitted fabrics can be improved.

[0029] 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, the principle of the present invention is specifically described.

[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 difference in shrinkage between the first component system PET and the second component system PBT is small, the monofilament does not have a special spiral curling structure. According to the minimum energy principle in physics, the system always tends to reach the state of minimum energy. The parallel composite monofilament will automatically adjust its configuration to distribute the tensile and compressive stresses on both sides of the monofilament in an optimal way to adapt to the tensile and compressive differentiation phenomenon of the spacer yarn being stretched on one side and compressed on the other side: 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 compression strain. The two-component system gives full play to their respective mechanical performance advantages, and the material is not easy to reach plastic strain or even limit strain, which enhances the durability of the spacer yarn and improves 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 present a spiral curling structure. LYCRA® T400® PTT / PET and LYCRA® T800® PBT / PET parallel multifilaments use this spiral curling structure to enhance the tensile resilience of the yarn. Compared with the spacer yarn without a spiral curling structure, the spiral curled spacer yarn exhibits excellent compression resilience. When the spacer knitted fabric undergoes a large compressive strain, the spiral curling structure undergoes significant global deformation, the spiral coil spacing decreases, and the stress on the spacer yarn body remains at a low level, only slight torsion occurs, and the mechanical behavior of the material remains in the elastic range. This deformation mode effectively disperses stress and avoids stress concentration, and the compression resilience of the spacer knitted fabric is improved.

[0033] Beneficial effects:

[0034] The invention discloses a high-rebound spacer knitted fabric, wherein the spacer yarn is a parallel thermoplastic polymer composite monofilament with a diameter of 0.07-5 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 high-resilience spacer knitted fabric without a spiral curling structure of the present invention when it is not compressed;

[0036] Figure 2 It is a schematic diagram of the high resilience spacer knitted fabric with a spiral curling structure of the present invention when it is not compressed;

[0037] Among them, 1 is a first planar knitted fabric layer, 2 is a second planar knitted fabric layer, and 3 is a spacer yarn. DETAILED DESCRIPTION

[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 are not intended 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 fall within the scope limited by the appended claims of the application equally.

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

[0040] (1) Compression stress value: According to 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 based on the stress value at 40% strain. The experiment is repeated 5 times for each embodiment and comparative example.

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

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

[0043] For the parallel thermoplastic polymer composite monofilament with a circular cross-sectional shape:

[0044] ;

[0045] in, is the curl curvature; is the curling curvature radius; is the difference in shrinkage 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 With radius The ratio of .

[0046] For the parallel type thermoplastic polymer composite monofilament with dumbbell or gourd shaped cross section:

[0047] ;

[0048] in, is the curl curvature; is the curling curvature radius; is the difference in shrinkage of the two-component system; the dumbbell shape and 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 With radius The ratio of .

[0049] The curl curvature can be estimated by testing the geometric configuration of the parallel thermoplastic polymer composite monofilament and approximating it with a standard three-dimensional spiral curve. The relationship is as follows:

[0050] ;

[0051] in, is the radius of the cylindrical surface where the three-dimensional spiral curve is located; It is the length of the cylinder in which a complete spiral is located, that is, the pitch.

[0052] It should be noted that this method is only applicable to calculating the difference in shrinkage of a two-component system of a parallel thermoplastic polymer composite monofilament with a spiral curling structure. The difference in shrinkage of a parallel thermoplastic polymer composite monofilament without a spiral curling structure cannot be given. Since the difference in shrinkage is the fundamental reason for determining whether there is a spiral curling structure, if the difference in shrinkage is small, there is no spiral curling configuration. Therefore, based on the minimum difference in shrinkage of the parallel composite monofilament with a spiral curling structure in the embodiment (6.8%), 6.8% is set as the critical shrinkage for whether there is a spiral curling configuration.

[0053] Example 1

[0054] A high-resilience spacer knitted fabric, such as Figure 1 As shown, it comprises 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 woven spacer yarns 3, wherein the spacer yarns 3 are parallel thermoplastic polymer composite monofilaments without a spiral curling structure;

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

[0057] The preparation process of the parallel thermoplastic polymer composite monofilament is as follows: the first component system and the second component system are extruded separately through a twin-screw extruder, the first component system is polyethylene terephthalate (PET), and the intrinsic viscosity is 1.03dL / g (China Petrochemical Corporation); the second component system is polybutylene terephthalate (PBT), and the intrinsic viscosity is 1.26dL / g (Suzhou Polydi Material Technology Co., Ltd.), and the volume ratio of the two component systems is 50:50; after the two component systems are combined, they are extruded from the same spinneret hole, and after passing through a section of air layer (5cm), they enter a coagulation water bath (70℃), and then successively undergo hot water stretching (90℃), hot air stretching (180℃) and heat setting (235℃, 1.8s), and each process of hot water stretching, hot air stretching and heat setting is equipped with stretching rollers before and after, a total of four stretching rollers, and finally wound on a winder;

[0058] 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 126m / min, four-pass stretching speed The speed is 120m / min, the overfeed rate is F=4.76%, and the winding speed is 118m / min;

[0059] 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;

[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 rear needle beds to form a chain structure. The padding 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 one through and one empty, and 600 D / 192F polyester multifilament is used for weft insertion on the front and rear needle beds respectively. The inlay yarn numbers of GB1 and GB6 are (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 full-threaded parallel thermoplastic polymer composite monofilament. The inlay yarn is alternately placed on the front and rear needle beds to form a chain structure to connect the first planar knitted fabric layer and the second planar knitted fabric layer. The inlay yarn number is (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 the high-rebound spacer knitted fabric is cyclically compressed 80,000 times at a compression strain of 70%, its thickness loss rate 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 is made of 0.25 mm PET monofilament 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 the high-rebound spacer knitted fabric is cyclically compressed 80,000 times at a compression strain of 70%, its thickness loss rate is 10.7±0.3%.

[0065] Comparing Comparative Example 1 with Example 1, the supporting property 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, comprising 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 are both mesh structures;

[0070] 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, wherein the first component system is polyethylene terephthalate (PET) with an intrinsic viscosity of 1.03 dL / g (Sinopec Group Co., Ltd.); and the second component system is a mixture of polyethylene terephthalate (PET) and polybutylene terephthalate (PBT) with a mass ratio of 30:70, and the intrinsic viscosity of PET in the second component system is 1.03 dL / g (Sinopec Group Co., Ltd.) The intrinsic viscosity of PBT in the second component system is 1.26dL / g (Suzhou Polydi Material Technology Co., Ltd.); the volume ratio of the two-component system is 25:75; the two-component system is extruded from the same spinneret after merging, and enters a coagulation water bath (70°C) after passing through an air layer (5cm), and then successively undergoes hot water stretching (90°C), hot air stretching (180°C) and heat setting (235°C, 1.8s). Each process of hot water stretching, hot air stretching and heat setting is equipped with stretching rollers before and after, a total of four stretching rollers, and finally wound on the 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 126m / min, four-pass stretching speed The speed is 120m / min, the overfeed rate is 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 rear needle beds to form a chain structure. The padding 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 one through and one empty, and 600 D / 192F polyester multifilament is used for weft insertion on the front and rear needle beds respectively. The inlay yarn numbers of GB1 and GB6 are (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 full-threaded parallel thermoplastic polymer composite monofilament. The inlay yarn is alternately placed on the front and rear needle beds to form a chain structure to connect the first planar knitted fabric layer and the second planar knitted fabric layer. The inlay yarn number is (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 longitudinal density is 5.89±0.23 rows / cm, the transverse 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 under a compressive strain of 70%, its thickness loss rate is 3.8±0.2%.

[0075] Example 3

[0076] A high-resilience spacer knitted fabric, comprising 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 are both mesh structures;

[0079] 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), and the intrinsic viscosity is 1.03 dL / g (Sinopec Group Co., Ltd.); the second component system is polyethylene terephthalate (PET), and the intrinsic viscosity is 0.67 dL / g (Sinopec Group Co., Ltd.), and the volume ratio of the two component systems is 50:50; the two component systems are combined and extruded from the same spinneret hole, and enter a coagulation water bath (70°C) after passing through an air layer (5 cm), and then successively undergo hot water stretching (90°C), hot air stretching (180°C) and heat setting (235°C, 1.8s), and each process of hot water stretching, hot air stretching and heat setting is equipped with stretching rollers before and after, a total of four stretching rollers, and finally wound on a winder;

[0080] 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 110m / 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;

[0081] The parallel 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-sectional shape of the parallel thermoplastic polymer composite monofilament is circular with a diameter of 0.25 mm; the curvature radius of the parallel thermoplastic polymer composite monofilament is is 1.19mm; the difference in shrinkage of the parallel 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 rear needle beds to form a chain structure. The padding 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 one through and one empty, and 600 D / 192F polyester multifilament is used for weft insertion on the front and rear needle beds respectively. The inlay yarn numbers of GB1 and GB6 are (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 full-threaded parallel thermoplastic polymer composite monofilament. The inlay yarn is alternately placed on the front and rear needle beds to form a chain structure to connect the first planar knitted fabric layer and the second planar knitted fabric layer. The inlay yarn number is (1-0-1-0 / 0-1-0-1)×5 / / ;

[0083] The high-resilience spacer knitted fabric has a thickness of 9.86±0.23mm, a longitudinal density of 5.66±0.13 rows / cm, a transverse density of 2.33±0.01 wales / cm, and a gram weight of 545±4.71g / m 2 The compression stress value is 5.4±1.2 kPa. 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-resilience 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 and are both dense structures;

[0088] The preparation process of the parallel thermoplastic polymer composite monofilament is as follows: the first component system and the 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 component systems is 60:40; the two component systems are combined and extruded from the same spinneret hole, and after passing through an air layer (5 cm), enter a coagulation water bath (70°C), and then successively undergo hot water stretching (90°C), hot air stretching (180°C) and heat setting (235°C, 1.8s), and each process of hot water stretching, hot air stretching and heat setting is equipped with stretching rollers before and after, a total of four stretching rollers, and finally wound on 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 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-sectional shape of the parallel thermoplastic polymer composite monofilament is circular with a diameter of 0.25 mm; the curvature radius of the parallel thermoplastic polymer composite monofilament is is 1.15mm; the shrinkage difference of the parallel thermoplastic polymer composite monofilament is 13.54%;

[0091] 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). GB1 and GB2 are fully threaded with 300D / 96F polyester multifilament to weave the first surface knitted fabric layer. The padding yarn numbers are: 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 weave The second planar knitted fabric layer, the inlay yarn numbers are: 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-through-one-out manner, and the parallel composite monofilament is inserted, and the first planar knitted fabric layer and the second planar knitted fabric layer are connected by alternately inlay yarns on the front and rear needle beds, and the inlay yarn numbers are: GB3: 1-0-3-2 / 3-2-1-0 / / , GB4: 3-2-1-0 / 1-0-3-2 / / ;

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

[0093] Example 5

[0094] A high-resilience spacer knitted fabric comprises 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, wherein the spacer yarns are parallel thermoplastic polymer composite monofilaments having a spiral curling structure;

[0096] The first knitted fabric layer and the second knitted fabric layer are both made of spandex (210D) covered with double layers of polyester (100D), and both have a dense structure;

[0097] The preparation process of the parallel thermoplastic polymer composite monofilament is as follows: the first component system and the 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 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; the two component systems are combined and extruded from the same spinneret hole, and after passing through an air layer (5 cm), enter a coagulation water bath (70°C), and then successively undergo hot water stretching (90°C), hot air stretching (180°C) and heat setting (235°C, 1.8s), and each process of hot water stretching, hot air stretching and heat setting is equipped with stretching rollers before and after, a total of four stretching rollers, and finally wound on a winder;

[0098] The process parameters are as follows: melt extrusion speed from spinneret The stretching speed is 3.8m / min. The second stretching speed is 32.9m / min The three-pass stretching speed is 148m / min 194m / min, four-pass stretching speed The speed is 180m / min, the overfeed rate is F=7.22%, and the winding speed is 178m / min;

[0099] The parallel 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-sectional shape of the parallel thermoplastic polymer composite monofilament is circular with a diameter of 0.12 mm; the curvature radius of the parallel thermoplastic polymer composite monofilament is is 0.93mm; the shrinkage difference of the parallel thermoplastic polymer composite monofilament is 6.8%.

[0100] The high-resilience spacer knitted fabric is knitted by double-sided weft knitting method; the spacer yarn is tucked alternately on the first knitted fabric layer and the second knitted fabric layer to connect the two knitted fabric layers, and the tuck positions of the first knitted fabric layer and the second knitted fabric layer are 4 stitches apart, and are knitted on an E7.2 computer flat knitting machine;

[0101] The high-resilience spacer knitted fabric has a thickness of 4.46±0.09mm, a longitudinal density of 18.03±0.33 rows / cm, a transverse density of 6.87±0.05 wales / cm, and a gram weight of 810±5.68g / m 2 ; The compression stress value is 4.0±0.7kPa; After the high-rebound 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 surface knitted fabric layer is made of 110D / 36F polyester with a dense structure; the second surface knitted fabric layer is made of 110D / 48F nylon with a colorful structure;

[0106] The parallel thermoplastic polymer composite monofilament is extruded by a twin-screw extruder to extrude the first component system and the second component system respectively; the first component system is polyethylene terephthalate (PET) with an intrinsic viscosity of 1.03dL / g (China Petrochemical Corporation); the second component system is polytrimethylene terephthalate (PTT) with an intrinsic viscosity of 1.05dL / g (Zhejiang Hengyi Petrochemical Research Institute Co., Ltd.); the volume ratio of the two component systems is 95:5; the two component systems are extruded from the same spinneret after merging, and enter a coagulation water bath (70°C) after passing through an air layer (5cm), and then successively undergo hot water stretching (90°C), hot air stretching (180°C) and heat setting (235°C, 1.8s), and each process of hot water stretching, hot air stretching and heat setting is equipped with stretching rollers before and after, a total of four stretching rollers, and finally wound on 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 is 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 by a double-sided weft knitting method; the spacer yarn is tucked alternately on the first knitted fabric layer and the second knitted fabric layer to connect the two knitted fabric layers, the spacer yarn is tucked alternately on the first knitted fabric layer and the second knitted fabric layer to connect the two knitted fabric layers, and the tuck positions of the first knitted fabric layer and the second knitted fabric layer are 1 stitch apart, and the knitting is performed on an E28 double-sided circular knitting machine;

[0110] The high-resilience 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 gram weight 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 longitudinal density is 37.2±2.2 rows / cm, the transverse 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 the high-rebound spacer knitted fabric is cyclically compressed 80,000 times at a compression strain of 70%, its thickness loss rate is 1.7±0.1%.

[0114] By 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 for the moment of inertia of a 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); the support of the spacer knitted fabric in Comparative Example 2 using 0.06mm diameter spacer yarns 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, characterized in that: The spacer yarn is a parallel thermoplastic polymer composite monofilament; 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; The first component system of the parallel thermoplastic polymer composite monofilament is polyethylene terephthalate, and the second component system is one or more of polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate and polyester thermoplastic elastomer; The diameter of the parallel thermoplastic polymer composite monofilament is not less than 0.07 mm.

2. A high-resilience spacer knitted fabric according to claim 1, characterized in that: The parallel thermoplastic polymer composite monofilament is obtained by respectively extruding a first component system and a second component system through a twin-screw extruder, and the two component systems are combined and extruded from the same spinneret hole and then stretched.

3. A high resilience spacer knitted fabric according to claim 1, characterized in that: The first component system and the second component system of the parallel thermoplastic polymer composite monofilament have a difference in shrinkage, and the difference in shrinkage is ≤15%.

4. A high-resilience spacer knitted fabric according to any one of claims 1 to 3, characterized in that: The cross-sectional shape of the parallel thermoplastic polymer composite monofilament is circular, dumbbell-shaped or gourd-shaped.

5. A high-resilience spacer knitted fabric according to any one of claims 1 to 3, characterized in that: The diameter of the parallel thermoplastic polymer composite monofilament is 0.07-5 mm.

6. A high-resilience spacer knitted fabric according to any one of claims 1 to 3, characterized in that: 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.

7. A high-resilience spacer knitted fabric according to any one of claims 1 to 3, characterized in that: 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.

8. A high-resilience spacer knitted fabric according to any one of claims 1 to 3, characterized in that: The high-resilience spacer knitted fabric is knitted by double-needle bed warp knitting or double-sided weft knitting.

9. A high-resilience spacer knitted fabric according to any one of claims 1 to 3, characterized in that: The thickness of the high-resilience spacer knitted fabric is 1-40 mm; After the high-resilience spacer knitted fabric is cyclically compressed for 80,000 times at a compression strain of 70%, the thickness loss rate is 3-5%.

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