Flat conductive composite fiber for sofa, preparation method and application thereof

Abstract

The present application relates to sofa fabric technical field.The present application discloses a kind of flat conductive composite fibers for sofa, it includes: fiber matrix, fiber matrix is flat strip, is made of polytetrafluoroethylene material;Conductive reinforcing layer, conductive reinforcing layer is flat net structure, the width of flat conductive composite fibers for sofa is greater than its thickness, the mesh of conductive reinforcing layer is filled with polytetrafluoroethylene material, and conductive reinforcing layer is used to provide conductive path and enhance the tensile strength of fiber matrix.The present application is embedded in flat polytetrafluoroethylene matrix by net conductive reinforcing layer, forms continuous conductive path, effectively eliminates static electricity, while significantly improving the tensile strength, wear resistance and wash resistance of fiber, avoids delamination and falls off.Flat design increases contact area, makes fabric flat and soft, comfortable feeling.The fiber preparation process is controllable, can be widely used in electromagnetic shielding, antistatic filtration, sofa fabric and radiation-proof tarpaulin and other fields, and the comprehensive performance is excellent.

Description

Technical Field

[0001] This invention relates to the field of sofa fabric technology, and in particular to a flat conductive composite fiber for sofas, its preparation method, and its application. Background Technology

[0002] As people's demands for quality home life continue to rise, the comfort, durability, and functionality of sofa fabrics are receiving increasing attention. Sofa fabrics are prone to static electricity during use due to friction between the human body or between fabrics, leading to dust accumulation and a noticeable electric shock sensation, severely impacting the user experience and indoor hygiene. To address this issue, the industry has attempted to introduce conductive fibers into sofa fabrics. Existing conductive fibers mainly involve several technical routes. One method involves blending conductive fillers such as conductive carbon black and carbon nanotubes with a polymer matrix and then spinning them. While this method has a relatively simple manufacturing process, high levels of conductive fillers significantly reduce the fiber's mechanical properties, and the conductive pathways are discontinuous, with surface resistivity typically reaching as high as 10⁻⁶. 7 For values ​​above Ω / □, the antistatic effect is limited, and the conductive filler is prone to detachment or aggregation after washing, resulting in severe performance degradation. Another method involves coating or plating a metal conductive layer onto the surface of ordinary fibers. These fibers initially exhibit good conductivity, but because the conductive layer only adheres to the fiber surface, its abrasion resistance is extremely poor. During textile processing and long-term use, it is easily peeled off due to friction, leading to rapid loss of conductivity. Furthermore, the coating layer affects the fiber's hand feel and softness.

[0003] Furthermore, the cross-sectional shape of existing conductive fibers is mostly circular, resulting in a small contact area with other fibers in the fabric, which is not conducive to the rapid conduction and dissipation of static electricity. Conductive fibers using low surface energy materials such as polytetrafluoroethylene (PTFE) as the matrix face challenges in achieving stable and durable conductivity while maintaining fiber flexibility, as PTFE itself is difficult to bond firmly with other materials. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention discloses a flat conductive composite fiber for sofas, its preparation method, and its application, which possesses excellent electrical conductivity, high tensile strength, good wear and washability, and a soft feel.

[0005] This invention discloses a flat conductive composite fiber for sofas, comprising:

[0006] The fiber matrix is ​​a flat, ribbon-like material made of polytetrafluoroethylene.

[0007] The conductive reinforcement layer has a flat mesh structure and is embedded inside the fiber matrix, extending continuously along the length of the fiber matrix.

[0008] The sofa uses flat conductive composite fibers whose width is greater than their thickness. The mesh of the conductive reinforcement layer is filled with polytetrafluoroethylene material. The conductive reinforcement layer is used to provide conductive paths and enhance the tensile strength of the fiber matrix.

[0009] Furthermore, the conductive reinforcement layer is a ductile conductive metal mesh layer or a conductive alloy mesh layer, and the material of the conductive metal mesh layer is selected from at least one of pure copper, tin-plated copper, phosphor bronze or stainless steel.

[0010] The diameter of a single wire in the conductive reinforcement layer is 1µm-20µm, and the mesh size is 10µm-100µm; the elongation at break of the conductive reinforcement layer is not less than 15%.

[0011] The width-to-thickness ratio of the flat conductive composite fiber used in sofas is 5:1-50:1.

[0012] Furthermore, the width of the flat conductive composite fiber used in the sofa is 200µm-2000µm, and the thickness is 15µm-100µm;

[0013] The thickness of the conductive reinforcement layer is 2µm-30µm, and the conductive reinforcement layer is located in the middle of the fiber matrix in the thickness direction. The difference between the distance between the conductive reinforcement layer and the upper and lower surfaces of the fiber matrix does not exceed 30% of the total thickness of the fiber matrix.

[0014] This invention discloses a method for preparing a flat conductive composite fiber for sofas. The method for preparing any of the above-mentioned flat conductive composite fibers for sofas includes the following steps:

[0015] S1 Preparation of polytetrafluoroethylene strip matrix: Polytetrafluoroethylene dispersion resin powder and extrusion aid are mixed evenly at a mass ratio of 1:0.1-1:0.5, and then pre-formed and extruded by plunger to obtain a strip precursor with a rectangular cross section;

[0016] S2 Preparation of conductive reinforcement layer: Provide a conductive reinforcement layer with a flat mesh structure, the width of which matches the width of the strip precursor;

[0017] S3 stack positioning: The conductive reinforcement layer is sandwiched between two strip precursors and pre-positioned by pressure rollers so that the conductive reinforcement layer is in a predetermined position in both the width and thickness directions.

[0018] S4 Calendered Composite: The pre-positioned laminated structure is calendered using a twin-roll calender to embed the conductive reinforcement layer into the strip precursor. The calendering gap is 1.2 to 2 times the target thickness of the flat conductive composite fiber for sofas.

[0019] S5 stretch forming: The calendered composite strip is stretched unidirectionally with a stretch ratio of 1.5 to 4 times, a stretching temperature range of 80℃ to 200℃, and a stretching force range of 0.5N to 5N.

[0020] S6 Sintering and Shaping: The stretched composite strip is sintered at 210℃-280℃ for 20min-60min to allow the extrusion aid to volatilize and the polytetrafluoroethylene to be shaped, resulting in a flat composite strip.

[0021] S7 Slitting: The flat composite strip is slit along its length into flat conductive composite fibers.

[0022] Furthermore, the extrusion aid is selected from at least one of the following: paraffin oil, petroleum ether, citric acid and guar gum powder;

[0023] The mixing process uses a high-speed mixer with a mixing rate of 500 rpm to 2000 rpm and a mixing time of 20 min to 60 min.

[0024] Furthermore, the preforming process employs a plunger-type preforming machine with a preforming pressure of 1 MPa-5 MPa.

[0025] The extrusion temperature of the plunger extrusion is 25℃-60℃, the extrusion rate is 1mm / second-10mm / second, and the width of the extruded strip precursor is 1mm-10mm, and the thickness is 0.1mm-1mm.

[0026] Furthermore, in the calendering and compounding step, the roll surface temperature of the twin-roll calender is 60℃-120℃, and the calendering rate is 0.5m / min-5m / min;

[0027] Pre-positioning is achieved by a guide roller and a limiting baffle set at the entrance of the calender. The limiting baffle is used to limit the position of the conductive reinforcement layer in the width direction.

[0028] Furthermore, the unidirectional stretching is performed using a multi-roll stretching machine with a stretching temperature of 100℃-180℃ and a stretching ratio of 2-3.5 times.

[0029] The width of the stretched composite strip is 1mm-5mm, and the thickness is 15µm-100µm.

[0030] Furthermore, the slitting is carried out using a rotary blade slitting machine or a laser slitting machine, with a slitting width of 200µm-2000µm; the cross-sectional edges of the flat conductive composite fibers for sofas obtained after slitting are right angles or rounded corners after heat setting.

[0031] This invention discloses the application of a flat conductive composite fiber for sofas, comprising:

[0032] Industrial textiles include electromagnetic shielding fabrics, antistatic industrial filter cloths, sofa fabrics, radiation-proof tarpaulins, or signal-shielding curtains.

[0033] The beneficial effects of this invention are:

[0034] This invention embeds a conductive reinforcing layer with a flat, mesh-like structure within a flat, strip-shaped polytetrafluoroethylene (PTFE) fiber matrix, filling the mesh pores with PTFE material. This not only creates a continuous and stable conductive path, quickly dissipating static charges generated by friction in the sofa fabric and effectively solving the problems of electrostatic adsorption and electric shock, but also improves the tensile strength and abrasion resistance of the fibers, avoiding the defects of conventional conductive fibers that are prone to breakage and fabric damage. The tight bond between the PTFE matrix and the embedded mesh structure ensures that the fibers maintain structural integrity and conductive stability even after long-term use and repeated cleaning, preventing interface delamination or detachment, thereby extending the lifespan of the sofa fabric.

[0035] The flat cross-section design of the fiber in this invention achieves a width-to-thickness ratio of 5:1 to 50:1, which increases the contact area with other fibers during textile processing, resulting in a smooth fabric surface and a soft feel without affecting the appearance and touch of sofa fabrics. The accompanying preparation method, through steps such as preforming, plunger extrusion, calendering and compounding, unidirectional stretching, and low-temperature sintering, controls the parameters of each process, enabling efficient production of flat conductive composite fibers with uniform dimensions and consistent performance. This fiber is not only suitable for sofa fabrics but can also be widely used in industrial textiles such as electromagnetic shielding fabrics, antistatic industrial filter cloths, radiation-proof tarpaulins, and signal-shielding curtains, offering significant advantages such as convenient processing, suitability for mass production, and excellent overall performance. Attached Figure Description

[0036] Figure 1 This is a schematic flowchart illustrating a method for preparing flat conductive composite fibers for sofas according to an embodiment of this application. Detailed Implementation

[0037] To enable those skilled in the art to better understand the present invention, the technical solutions in the specific embodiments of the present invention will be clearly and completely described below.

[0038] This invention discloses a flat conductive composite fiber for sofas, comprising:

[0039] The fiber matrix is ​​a flat, ribbon-like material made of polytetrafluoroethylene.

[0040] The conductive reinforcement layer has a flat mesh structure and is embedded inside the fiber matrix, extending continuously along the length of the fiber matrix.

[0041] The sofa uses flat conductive composite fibers whose width is greater than their thickness. The mesh of the conductive reinforcement layer is filled with polytetrafluoroethylene material. The conductive reinforcement layer is used to provide conductive paths and enhance the tensile strength of the fiber matrix.

[0042] The fiber matrix of this invention is made of polytetrafluoroethylene (PTFE) material, processed into a flat strip shape using a specific process. Its flat structure increases the contact area between the fiber and other fibers in the fabric, laying the foundation for subsequent textile processing and antistatic effects. The conductive reinforcement layer adopts a flat mesh structure, embedded within the fiber matrix during fiber preparation and extending continuously along the fiber length to ensure the continuity of the conductive path. The mesh openings are filled with PTFE material, integrating the conductive reinforcement layer with the fiber matrix to prevent delamination and detachment. Simultaneously, the support provided by the mesh structure effectively enhances the tensile strength of the fiber matrix, meeting the needs of sofa fabrics subjected to prolonged sitting and friction.

[0043] The conductive reinforcement layer is embedded within the polytetrafluoroethylene (PTFE) matrix. Its mesh structure forms a continuous and stable conductive path, quickly dissipating static charges generated by friction between the user and the fabric. This solves the problems of static electricity attracting dust and electric shock upon contact, improving user comfort. The conductive reinforcement layer not only provides conductivity but also enhances the tensile strength and abrasion resistance of the fibers, avoiding the breakage and fabric damage issues common with conventional conductive fibers. This extends the lifespan of the sofa fabric and meets the wear and tear requirements of long-term sofa use. PTFE material has excellent stain and wash resistance, maintaining stable conductivity and structural integrity even after multiple cleanings, eliminating concerns about the antistatic effect losing its effectiveness. The flat structure ensures a smooth fabric surface and soft feel after weaving, without affecting the appearance and touch of the sofa fabric. Simultaneously, the tight bond between the mesh structure and the matrix ensures that the fibers are not easily deformed during weaving, facilitating processing and making it suitable for mass production of sofa fabrics.

[0044] In one embodiment, the conductive reinforcement layer is a ductile conductive metal mesh layer or a conductive alloy mesh layer, and the material of the conductive metal mesh layer is selected from at least one of pure copper, tin-plated copper, phosphor bronze or stainless steel.

[0045] The diameter of a single wire in the conductive reinforcement layer is 1µm-20µm, and the mesh size is 10µm-100µm; the elongation at break of the conductive reinforcement layer is not less than 15%.

[0046] The width-to-thickness ratio of the flat conductive composite fiber used in sofas is 5:1-50:1.

[0047] The conductive reinforcement layer is made of conductive metal mesh or conductive alloy mesh with good ductility. Materials preferably include pure copper, tin-plated copper, phosphor bronze, or stainless steel. These materials combine excellent conductivity with mechanical ductility, making them suitable for subsequent textile processing and long-term use of sofa fibers. The diameter of each wire in the conductive reinforcement layer is controlled between 1µm and 20µm, and the mesh size is set between 10µm and 100µm. This ensures the continuity of the mesh structure, forming a stable conductive path, while also allowing the polytetrafluoroethylene (PTFE) vinyl ester material to fully fill the mesh, ensuring a tight bond between the conductive reinforcement layer and the fiber matrix, preventing delamination and detachment during use. The elongation at break of the conductive reinforcement layer is no less than 15%, effectively adapting to the stretching process during fiber preparation, preventing wire breakage during stretching, and ensuring the integrity of the conductive path. The width-to-thickness ratio of the flat conductive composite fiber used in sofas is controlled between 5:1 and 50:1. The flat structure can increase the contact area between the fiber and other textile fibers, improve the smoothness and fit of the fabric after weaving, meet the weaving needs of sofa fabrics, and take into account both processing convenience and user experience.

[0048] In one embodiment, the width of the flat conductive composite fiber for sofas is 200µm-2000µm and the thickness is 15µm-100µm; the thickness of the conductive reinforcement layer is 2µm-30µm, and the conductive reinforcement layer is located in the middle of the fiber matrix in the thickness direction, and the difference between the conductive reinforcement layer and the upper and lower surfaces of the fiber matrix does not exceed 30% of the total thickness of the fiber matrix.

[0049] The fiber width is set at 200µm-2000µm, and the thickness at 15µm-100µm, balancing the textile processing needs of sofa fabrics with the feel of the fabric. This avoids the fabric becoming stiff and prickly due to excessively coarse fibers, and prevents the fiber's tensile strength and conductivity from being too thin. The thickness of the conductive reinforcement layer is controlled between 2µm and 30µm, matching the thickness of the fiber matrix. This prevents the overall fiber stiffness from increasing due to excessive thickness, and the conductivity and reinforcement effect from weakening due to excessive thinness. The conductive reinforcement layer is placed in the center of the fiber matrix's thickness direction, and the difference in distance between it and the upper and lower surfaces of the matrix is ​​controlled to not exceed 30% of the total matrix thickness. Through pre-positioning, guiding, and precise calendering processes during manufacturing, the conductive reinforcement layer is centrally positioned, ensuring uniform fiber stress and preventing misalignment or delamination during use or textile production.

[0050] The interfacial bonding strength and flexural fatigue resistance between polytetrafluoroethylene (PTFE) and the conductive metal reinforcement layer are excellent. Although PTFE is a low surface energy material, during the preparation process of this invention, the conductive reinforcement layer is subjected to bidirectional stress during calendering and stretching. The micro-rough structure on the surface of the metal mesh can be embedded into the PTFE body to form a mechanical interlock. Combined with the shrinkage and encapsulation effect of PTFE after sintering and shaping, the interfacial bonding strength is sufficient to resist shear and peel stress during normal use. The conductive reinforcement layer uses a metal mesh with a breaking elongation of not less than 15%, whose ductility matches the elongation of the PTFE body at the stretching temperature, avoiding interfacial delamination caused by inconsistent deformation during bending. The flat cross-section design ensures that when the fiber is bent, the neutral layer is located in the middle of the thickness direction, and the conductive reinforcement layer is precisely located near this neutral layer. Therefore, the tensile and compressive strains on the conductive reinforcement layer during bending are minimized, reducing the risk of fatigue delamination. Based on the above design principles, it can be reasonably expected that the fiber of this invention can maintain interfacial integrity and conductive stability even under repeated flexing, such as more than 100,000 cycles. To further enhance the bonding strength, the surface of the metal mesh can be treated with a coupling agent, such as a silane coupling agent or a titanate coupling agent.

[0051] The optimal fiber width and thickness allow for easy blending with or weaving of ordinary textile fibers, resulting in a smooth, soft fabric surface that doesn't compromise the appearance, texture, or comfort of the sofa upholstery. Simultaneously, it ensures sufficient mechanical strength to withstand the prolonged sitting and friction associated with sofa use. The appropriately sized conductive reinforcement layer balances conductivity with fiber softness, preventing stiffness caused by an excessively thick layer. The centrally positioned design ensures even stress distribution on the fibers, reducing breakage during stretching and bending, extending the sofa fabric's lifespan. It also ensures a uniform distribution of the conductive reinforcement layer, forming a continuous and stable conductive path for more efficient static dissipation, effectively resolving static electricity issues in sofa fabrics. Furthermore, the central structure ensures a tighter bond between the conductive reinforcement layer and the matrix, preventing detachment and maintaining stable performance even after multiple washes, making it suitable for mass production of sofa fabrics.

[0052] This invention discloses a method for preparing flat conductive composite fibers for sofas, the method comprising the following steps:

[0053] S1 Preparation of polytetrafluoroethylene strip matrix: Polytetrafluoroethylene dispersion resin powder and extrusion aid are mixed evenly at a mass ratio of 1:0.1-1:0.5, and then pre-formed and extruded by plunger to obtain a strip precursor with a rectangular cross section;

[0054] S2 Preparation of conductive reinforcement layer: Provide a conductive reinforcement layer with a flat mesh structure, the width of which matches the width of the strip precursor;

[0055] S3 stack positioning: The conductive reinforcement layer is sandwiched between two strip precursors and pre-positioned by pressure rollers so that the conductive reinforcement layer is in a predetermined position in both the width and thickness directions.

[0056] S4 Calendered Composite: The pre-positioned laminated structure is calendered using a twin-roll calender to embed the conductive reinforcement layer into the strip precursor. The calendering gap is 1.2 to 2 times the target thickness of the flat conductive composite fiber for sofas.

[0057] S5 stretch forming: The calendered composite strip is stretched unidirectionally with a stretch ratio of 1.5 to 4 times, a stretching temperature range of 80℃ to 200℃, and a stretching force range of 0.5N to 5N.

[0058] S6 Sintering and Shaping: The stretched composite strip is sintered at 210℃-280℃ for 20min-60min to allow the extrusion aid to volatilize and the polytetrafluoroethylene to be shaped, resulting in a flat composite strip.

[0059] S7 Slitting: The flat composite strip is slit along its length into multiple flat conductive composite fibers for sofas as described in any one of claims 1-4.

[0060] In step S1, polytetrafluoroethylene (PTFE) dispersion resin powder and extrusion aid are mixed uniformly in a specific ratio. The extrusion aid reduces the extrusion viscosity of the resin powder, ensuring a uniform mixing system. After pre-forming, a rectangular strip precursor is obtained by plunger extrusion, laying the foundation for subsequent composite molding. In step S2, a flat mesh conductive reinforcement layer matching the width of the strip precursor is prepared to ensure that the conductive layer can fully adapt to the matrix during subsequent composite molding, avoiding uneven conductivity caused by width deviation. In step S3, the conductive reinforcement layer is precisely sandwiched between two strip precursor layers using a pressure roller for pre-positioning, achieving positioning of the conductive reinforcement layer in both width and thickness directions and preventing misalignment in subsequent processes. In step S4, the laminated structure is calendered using a twin-roll calender, with a reasonable calendering gap set to ensure that the conductive reinforcement layer is smoothly embedded into the strip precursor, achieving initial bonding between the two. In step S5, the dimensions and strength of the composite strip are adjusted under specific temperature and tension through unidirectional stretching, improving the tensile properties of the fibers. Step S6 involves sintering and shaping to allow the extrusion aid to fully volatilize and simultaneously to set the polytetrafluoroethylene material, enhancing the stability of the fiber structure. Step S7 involves slitting to cut the flat composite strip into fibers of the target size, ultimately obtaining flat conductive composite fibers that meet the requirements of sofa fabrics.

[0061] The sintering temperature range of 210℃-280℃ in this invention is lower than the typical melting point of polytetrafluoroethylene (PTFE). This low-temperature sintering process relies on the following technical measures: the PTFE dispersion resin used in this application contains 0.5%-3% by mass of sintering aids, such as perfluoropropyl vinyl ether comonomer, nano-silica, or nano-alumina. These aids promote localized movement and entanglement of PTFE molecular chains during sintering, enabling densification and shaping at temperatures below the melting point. This low-temperature sintering process allows for sufficient volatilization of the extrusion aids and ensures the fiber matrix acquires sufficient mechanical strength and structural stability. Those skilled in the art can adjust the sintering temperature and time within the 210℃-280℃ range based on the actual thermal properties of the selected PTFE resin to achieve the optimal shaping effect.

[0062] As one implementation method, the extrusion aid is selected from at least one of the following: paraffin oil, petroleum ether, citric acid and guar gum powder;

[0063] The mixing process uses a high-speed mixer with a mixing rate of 500 rpm to 2000 rpm and a mixing time of 20 min to 60 min.

[0064] The extrusion aid is selected from at least one of the following: paraffin oil, petroleum ether, citric acid, and guar gum powder. This type of extrusion aid has good compatibility with polytetrafluoroethylene (PTFE) dispersion resin powder, effectively reducing the extrusion viscosity of the resin powder and facilitating subsequent molding processes. The mixing process utilizes a high-speed mixer. PTFE dispersion resin powder and the extrusion aid are added to the equipment at a preset ratio, with the mixing rate controlled between 500 rpm and 2000 rpm, and the mixing time maintained between 20 min and 60 min. Through the shearing action of high-speed stirring, the extrusion aid is evenly penetrated between the resin powder particles, breaking up particle agglomeration and forming a homogeneous mixture of resin and extrusion aid. This avoids defects in subsequent extrusion molding caused by excessive or insufficient extrusion aid in certain areas, ensuring the preparation of a uniform and dimensionally stable strip-shaped precursor, suitable for subsequent production processes of flat conductive composite fibers used in sofas.

[0065] The selected extrusion aids are all adapted to the processing characteristics of PTFE materials. They effectively reduce resin extrusion viscosity, making subsequent plunger extrusion smoother, and completely volatilize during the subsequent sintering process, leaving no residue inside the fibers to avoid affecting the fiber feel and safety. This meets the requirements of sofa fabrics for being skin-friendly and odorless. The uniform mixing system ensures that the extruded strip precursors are of uniform size and dense texture, reducing molding defects. It also improves the bonding strength between the conductive reinforcement layer and the fiber matrix, extending the service life of the sofa fabric. Furthermore, the mixing process is simple to operate, highly efficient, and suitable for mass production, balancing practicality and economy.

[0066] As one implementation method, preforming is carried out using a plunger-type preforming machine, with a preforming pressure of 1 MPa-5 MPa;

[0067] The extrusion temperature of the plunger extrusion is 25℃-60℃, the extrusion rate is 1mm / second-10mm / second, and the width of the extruded strip precursor is 1mm-10mm, and the thickness is 0.1mm-1mm.

[0068] The preforming process utilizes a plunger-type preforming machine, controlling the preforming pressure at 1-5 MPa. This compacts the uniformly mixed PTFE dispersion resin and extrusion aid mixture, forming a dense, non-porous preform to prevent defects such as bubbles and cracking during extrusion. After preforming, a plunger-type extruder is used for extrusion. Controlling the extrusion temperature at 25-60 degrees Celsius ensures the extrusion aid remains stable, preventing premature volatilization that could hinder extrusion and maintaining the good plasticity of the PTFE resin. The extrusion rate is controlled at 1-10 mm per second, ensuring a smooth and orderly extrusion process, ultimately yielding a rectangular strip-shaped precursor with a width of 1-10 mm and a thickness of 0.1-1 mm.

[0069] Preforming pressure ensures thorough compaction of the resin and extrusion aid mixture, reducing internal porosity and resulting in a uniform and dense precursor texture. This prevents delamination and damage during processing, thus guaranteeing the mechanical strength of the final fibers. Controlling the extrusion temperature and rate prevents premature evaporation of the extrusion aid, avoiding extrusion defects and ensuring dimensional stability and a smooth surface of the precursor. This prevents dimensional deviations from affecting the positioning and lamination of the subsequent conductive reinforcement layer. The strip-shaped precursor's dimensions are adapted to subsequent processes, facilitating the clamping and calendering of the conductive reinforcement layer. Subsequent stretching and slitting also allow for fiber sizes tailored to sofa fabric requirements. Furthermore, the entire process is easy to control and operate, suitable for mass production, effectively improving production efficiency, reducing scrap rates, and ensuring consistent product performance.

[0070] In one implementation method, during the calendering and compounding step, the roll surface temperature of the twin-roll calender is 60℃-120℃, and the calendering rate is 0.5m / min-5m / min.

[0071] Pre-positioning is achieved by a guide roller and a limiting baffle set at the entrance of the calender. The limiting baffle is used to limit the position of the conductive reinforcement layer in the width direction.

[0072] The roll surface temperature of the twin-roll calender is controlled between 60-120 degrees Celsius, which appropriately softens the strip precursor, improves its plasticity, and facilitates the smooth embedding of the conductive reinforcement layer. Simultaneously, it avoids premature volatilization of extrusion aids or matrix deformation due to excessively high temperatures. The calendering rate is set at 0.5m / min-5m / min, ensuring a smooth and orderly calendering process that allows the conductive reinforcement layer to fully adhere to the matrix, reducing defects such as bubbles and delamination. Pre-positioning is achieved through guide rollers and limiting baffles located at the calender inlet. The guide rollers guide the laminated structure smoothly into the calender, while the limiting baffles precisely define the position of the conductive reinforcement layer in the width direction, preventing it from shifting. This ensures that the conductive reinforcement layer always matches the width of the strip precursor, guaranteeing the uniformity of subsequent calendering and compounding.

[0073] As one implementation method, unidirectional stretching is performed using a multi-roll stretching machine, with a stretching temperature of 100℃-180℃ and a stretching ratio of 2 to 3.5 times;

[0074] The width of the stretched composite strip is 1mm-5mm, and the thickness is 15µm-100µm.

[0075] Maintaining the stretching temperature between 100-180 degrees Celsius keeps the polytetrafluoroethylene (PTFE) substrate in a suitable softened state, improving material toughness and preventing breakage or damage during stretching. This also ensures that the conductive reinforcement layer and the substrate are stretched synchronously without separation. The stretching ratio is set to 2-3.5 times. By adjusting the stretching rate and tension, the composite strip is gradually stretched until its dimensions meet the preset standards. After stretching, the width of the composite strip is controlled between 1mm and 5mm, and the thickness is 15µm-100µm.

[0076] As one implementation method, slitting is performed using a rotary blade slitting machine or a laser slitting machine, with a slitting width of 200µm-2000µm. The resulting flat conductive composite fiber for sofas has right-angled or heat-set rounded edges. After the slitting step, the ends of the conductive reinforcement layer mesh may be slightly exposed at both ends of the cross-section along the fiber's length. This is due to the slitting blade directly cutting the composite strip and is a normal phenomenon. This exposure is limited to the end points of the cross-section, with an exposed length not exceeding the diameter of a single mesh wire, and the conductive reinforcement layer remains completely covered by PTFE in other areas along the fiber's width and thickness directions. In actual weaving and use, due to the extremely short exposed length and the certain fluidity of the PTFE, it will not cause the conductive reinforcement layer to detach or oxidize and fail. When heat-setting rounded edges are applied after slitting, heating allows the PTFE to soften and flow slightly, automatically wrapping around the exposed mesh ends of the cross-section, achieving a self-sealing effect.

[0077] In one embodiment of the present invention, a rotary blade slitting machine or a laser slitting machine is selected for the slitting process, which can be flexibly chosen according to production needs, balancing slitting efficiency and precision. During slitting, the sintered and shaped flat composite strip is uniformly conveyed to the slitting equipment. By adjusting the equipment speed and the strip conveying speed, the composite strip is slitted along its length into fibers with a width of 200-2000µm, which meets the size requirements of flat conductive composite fibers for sofas. The edges of the fiber cross-sections obtained after slitting are set as right angles or rounded corners after heat setting. The right angle edges ensure the regularity of the fiber structure, facilitating subsequent textile processing; the rounded corner edges are softened and polished by a low-temperature heat setting process after slitting, removing burrs and avoiding sharp edges after slitting that would affect use.

[0078] This invention discloses the application of a flat conductive composite fiber for sofas in the preparation of industrial textiles, comprising:

[0079] Industrial textiles include electromagnetic shielding fabrics, antistatic industrial filter cloths, sofa fabrics, radiation-proof tarpaulins, or signal-shielding curtains.

[0080] Example

[0081] Example 1

[0082] The specific steps for preparing flat conductive composite fibers for sofas are as follows:

[0083] S1. Preparation of polytetrafluoroethylene (PTFE) strip matrix: PTFE dispersion resin powder and extrusion aid paraffin oil were mixed uniformly at a mass ratio of 1:0.3 using a high-speed mixer at a mixing rate of 1200 rpm for 40 min. The mixture was then pre-formed using a plunger-type preforming machine at a preforming pressure of 3 MPa. Finally, it was extruded using a plunger-type extruder at an extrusion temperature of 40℃ and an extrusion rate of 5 mm / s to obtain a rectangular strip precursor with a width of 5 mm and a thickness of 0.5 mm.

[0084] S2. Preparation of conductive reinforcement layer: Provide a pure copper conductive metal mesh layer with a flat mesh structure, with a single mesh wire diameter of 10µm, a mesh aperture of 50µm, a breaking elongation of 30%, and a width that matches the width of the strip precursor.

[0085] S3. Lamination and positioning: The conductive reinforcement layer is sandwiched between two strip precursors and pre-positioned by pressure rollers. At the same time, the position of the conductive reinforcement layer in the width direction is limited by the guide rollers and limiting baffles at the entrance of the calender.

[0086] S4. Calendering and compounding: The pre-positioned laminated structure is calendered using a twin-roll calender. The roll surface temperature of the twin-roll calender is 80℃, the calendering rate is 2m / min, and the calendering gap is 1.5 times the target fiber thickness.

[0087] S5. Stretching: Unidirectional stretching is performed using a multi-roll stretching machine at a stretching temperature of 140℃, a stretching ratio of 2.5 times, a stretching force of 3N, and the width of the composite strip after stretching is 2mm and the thickness is 50µm.

[0088] S6. Sintering and shaping: The stretched composite strip is sintered at 250℃ for 40 minutes to allow the extrusion aid to volatilize and the polytetrafluoroethylene to be shaped, resulting in a flat composite strip.

[0089] S7. Slitting: A rotary blade slitting machine is used, with a slitting width of 1000µm. After slitting, the edges of the fiber cross-section are rounded after heat setting.

[0090] The final flat conductive composite fiber for sofas has the following characteristics: 1000µm width, 50µm thickness, and a width-to-thickness ratio of 20:1; the conductive reinforcement layer has a thickness of 15µm and is located in the middle of the fiber matrix in the thickness direction, with the difference in distance between it and the upper and lower surfaces of the matrix not exceeding 8% of the total thickness of the matrix; the fiber matrix is ​​polytetrafluoroethylene, and the conductive reinforcement layer is a pure copper mesh layer.

[0091] Performance test results: Surface resistivity 1.2×10 6 Ω / □, breaking strength 8.5cN / dtex, wear resistance 52000 cycles, surface resistivity change rate after 50 water washes 9.6%.

[0092] Example 2

[0093] The difference from Example 1 is as follows: the extrusion aid is petroleum ether, the mass ratio of polytetrafluoroethylene dispersion resin powder to extrusion aid is 1:0.1; the mixing rate is 500 rpm, the mixing time is 20 min; the conductive reinforcement layer is a tin-plated copper mesh layer, the diameter of a single mesh wire is 1µm, the mesh aperture is 10µm, and the elongation at break is 25%; the slitting is done with a laser slitting machine, the slitting width is 200µm, and the edge of the fiber cross section after slitting is a right angle.

[0094] Performance test results: Surface resistivity 1.0×10 6 Ω / □, breaking strength 7.8cN / dtex, wear resistance 48,000 cycles, surface resistivity change rate after 50 water washes 8.4%.

[0095] Example 3

[0096] The difference from Example 1 is as follows: the extrusion aid is a mixture of citric acid and guar gum powder, the mass ratio of polytetrafluoroethylene dispersion resin powder to extrusion aid is 1:0.5; the mixing rate is 2000 rpm, the mixing time is 60 min; the preforming pressure is 1 MPa, the extrusion temperature is 25℃, the extrusion rate is 1 mm / s, the width of the strip precursor is 1 mm, and the thickness is 0.1 mm; the conductive reinforcement layer is a phosphor bronze mesh layer with a single mesh wire diameter of 20 µm, a mesh aperture of 100 µm, and a breaking elongation of 35%.

[0097] Performance test results: Surface resistivity 1.5×10 6 Ω / □, breaking strength 9.2cN / dtex, wear resistance 55,000 cycles, surface resistivity change rate after 50 water washes 7%.

[0098] Example 4

[0099] Unlike Example 1, in the calendering and composite step, the roll surface temperature of the twin-roll calender is 60°C, the calendering rate is 0.5 m / min, and the calendering gap is 1.2 times the target fiber thickness; the stretching temperature is 100°C, the stretching ratio is 2 times, the stretching force is 0.5 N, and the width of the composite strip after stretching is 1 mm and the thickness is 15 µm; the fiber width is 200 µm and the thickness is 15 µm, with a width-to-thickness ratio of 13.3:1; and the thickness of the conductive reinforcement layer is 2 µm.

[0100] Performance test results: Surface resistivity 1.3×10 6 Ω / □, tensile strength 7.2cN / dtex, fabrics made from this fiber can withstand 45,000 abrasion cycles, and the surface resistivity changes by 10% after 50 washes.

[0101] Example 5

[0102] Unlike Example 1, in the calendering and composite step, the roll surface temperature of the twin-roll calender is 120°C, the calendering rate is 5m / min, and the calendering gap is twice the target fiber thickness; the stretching temperature is 180°C, the stretching ratio is 3.5 times, the stretching force is 5N, and the width of the composite strip after stretching is 5mm and the thickness is 100µm; the fiber width is 2000µm and the thickness is 100µm, with a width-to-thickness ratio of 20:1; the conductive reinforcement layer is 30µm thick, and the difference in distance between it and the upper and lower surfaces of the matrix does not exceed 30% of the total thickness of the matrix.

[0103] Performance test results: Surface resistivity 1.1×10⁻⁶ 6 Ω / □, tensile strength 9.5cN / dtex, fabrics made from this fiber can withstand 58,000 abrasion cycles, and the surface resistivity changes by 13.1% after 50 washes.

[0104] Example 6

[0105] The differences from Example 1 are as follows: the extrusion temperature is 60°C, the extrusion rate is 10 mm / s, the width of the strip precursor is 10 mm and the thickness is 1 mm; the conductive reinforcement layer is a stainless steel mesh layer with a breaking elongation of 40%; the sintering temperature is 220°C and the sintering time is 20 min; the slitting width is 2000 µm and the edges of the fiber cross-section after slitting are right angles.

[0106] Performance test results: Surface resistivity 1.4×10 6Ω / □, tensile strength 8.8cN / dtex, fabrics made from this fiber can withstand 53,000 abrasion cycles, and the surface resistivity changes by 13.3% after 50 washes.

[0107] Comparative Example

[0108] Comparative Example 1

[0109] The conductive composite fiber for sofas is prepared using existing technology. It has no embedded mesh conductive reinforcement layer and is a single-component circular fiber composed of polytetrafluoroethylene and conductive carbon black. The specific steps are as follows:

[0110] Polytetrafluoroethylene dispersion resin powder was mixed with 20% by mass of conductive carbon black and paraffin oil extrusion aid at a mass ratio of 1:0.2:0.3, and the mixture was homogeneous at a mixing rate of 1200 rpm for 40 min. The mixture was then preformed using a plunger preforming machine at a pressure of 3 MPa and extruded using a plunger extruder at a temperature of 40℃ and a speed of 5 mm / s to obtain a circular cross-section precursor. The precursor was then stretched using a multi-roll stretching machine at a temperature of 140℃, a ratio of 2.5 times, a tensile force of 3 N, and sintered at 250℃ for 40 min to obtain circular conductive composite fibers with a fiber diameter of 50 µm.

[0111] Performance test results: Surface resistivity 8.5×10 8 Ω / □, tensile strength 5.2cN / dtex, fabrics made from this fiber can withstand 28,000 abrasion cycles, and the surface resistivity changes by 28.6% after 50 washes.

[0112] Comparative Example 2

[0113] Unlike Comparative Example 1, the conductive filler is 15% carbon nanotubes by mass. The fibers are flat, 1000µm wide, and 50µm thick. There is no embedded conductive reinforcement layer. It is only a blend of polytetrafluoroethylene and carbon nanotubes.

[0114] Performance test results: Surface resistivity 4.2×10 7 Ω / □, tensile strength 5.8cN / dtex, fabrics made from this fiber can withstand 32,000 abrasion cycles, and the surface resistivity changes by 22.3% after 50 washes.

[0115] Comparative Example 3

[0116] Unlike Comparative Example 1, this one was prepared by coating a conductive layer on the surface. It used a polytetrafluoroethylene circular fiber with a diameter of 50µm as the substrate and coated a pure copper conductive layer with a thickness of 15µm on the surface. It did not have an embedded mesh structure. The other preparation parameters were the same as those of Comparative Example 1.

[0117] Performance test results: Surface resistivity 3.6×10 7Ω / □, tensile strength 4.9cN / dtex, fabrics made from this fiber can withstand 22,000 abrasion cycles, and the surface resistivity changes by 45.7% after 50 washes.

[0118] Performance testing methods

[0119] 1. Surface resistivity: Tested according to Part 3 of GB / T12703-2021 "Evaluation of electrostatic properties of textiles" with an ambient temperature of 23℃ and a relative humidity of 50%. Five points were tested for each sample, and the average value was taken.

[0120] 2. Breaking strength: Tested according to GB / T14344-2017 "Test Method for Tensile Properties of Chemical Fiber Filaments", with a tensile speed of 10 mm / min, a clamping distance of 50 mm, and 5 filaments for each sample, and the average value is taken.

[0121] 3. Abrasion resistance: Tested according to GB / T21196.1-2007 "Textiles - Martindale Abrasion Test - Part 1: Martindale Abrasion Tester", with a load of 12 kPa. The test was stopped when the abrasion cycle reached the point of pilling, breakage, or electrical failure, and the average value was taken.

[0122] 4. Washing stability: Perform 50 washes according to GB / T8629-2017 "Home Washing and Drying Procedures for Textile Testing". After washing, test the surface resistivity again and calculate the resistivity change rate (change rate = (resistivity after washing - resistivity before washing) / resistivity before washing × 100%).

[0123] The performance comparison results are shown in Table 1 below.

[0124]

[0125] Table 1

[0126] The products in Examples 1-6 all have a surface resistivity of less than 2×10⁻⁶. 6 The tensile strength of this fiber is higher than 7cN / dtex, and the fabrics made from this fiber can withstand more than 45,000 abrasion cycles. After 50 washes, the surface resistivity change rate is less than 15%. It also exhibits excellent antistatic properties, mechanical properties, abrasion resistance and washing stability.

[0127] Comparative Examples 1-3: The products of the prior art all have a surface resistivity higher than 3×10⁻⁶. 7 The tensile strength of the fiber is less than 6 cN / dtex, the abrasion resistance of the fabric made from the fiber is less than 35,000 times, and the resistivity change rate after washing is greater than 20%. Among them, Comparative Example 3 has the worst performance because the conductive coating on the surface is easy to fall off.

[0128] In summary, the flat conductive composite fiber for sofas prepared by this invention has superior performance compared to existing technologies and is fully compatible with the antistatic, wear-resistant, and durable requirements of sofa fabrics.

[0129] It should be understood that those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A flat conductive composite fiber for sofas, characterized in that, include: The fiber matrix is ​​a flat, ribbon-like material made of polytetrafluoroethylene. The conductive reinforcement layer has a flat mesh structure and is embedded inside the fiber matrix, extending continuously along the length of the fiber matrix. The sofa uses flat conductive composite fibers whose width is greater than their thickness. The mesh of the conductive reinforcement layer is filled with polytetrafluoroethylene material. The conductive reinforcement layer is used to provide conductive paths and enhance the tensile strength of the fiber matrix.

2. The flat conductive composite fiber for sofas according to claim 1, characterized in that: The conductive reinforcement layer is a ductile conductive metal mesh or conductive alloy mesh, and the material of the conductive metal mesh is selected from at least one of pure copper, tin-plated copper, phosphor bronze or stainless steel. The diameter of a single wire in the conductive reinforcement layer is 1µm-20µm, and the mesh size is 10µm-100µm; the elongation at break of the conductive reinforcement layer is not less than 15%. The width-to-thickness ratio of the flat conductive composite fiber used in sofas is 5:1-50:

1.

3. The flat conductive composite fiber for sofas according to claim 1, characterized in that: The width of the flat conductive composite fiber used in sofas is 200µm-2000µm, and the thickness is 15µm-100µm. The thickness of the conductive reinforcement layer is 2µm-30µm, and the conductive reinforcement layer is located in the middle of the fiber matrix in the thickness direction. The difference between the distance between the conductive reinforcement layer and the upper and lower surfaces of the fiber matrix does not exceed 30% of the total thickness of the fiber matrix.

4. A method for preparing a flat conductive composite fiber for sofas, comprising preparing the flat conductive composite fiber for sofas as described in any one of claims 1-3, characterized in that, The preparation method includes the following steps: S1 Preparation of polytetrafluoroethylene strip matrix: Polytetrafluoroethylene dispersion resin powder and extrusion aid are mixed evenly at a mass ratio of 1:0.1-1:0.5, and then pre-formed and extruded by plunger to obtain a strip precursor with a rectangular cross section; S2 Preparation of conductive reinforcement layer: Provide a conductive reinforcement layer with a flat mesh structure, the width of which matches the width of the strip precursor; S3 stack positioning: The conductive reinforcement layer is sandwiched between two strip precursors and pre-positioned by pressure rollers so that the conductive reinforcement layer is in a predetermined position in both the width and thickness directions. S4 Calendered Composite: The pre-positioned laminated structure is calendered using a twin-roll calender to embed the conductive reinforcement layer into the strip precursor. The calendering gap is 1.2 to 2 times the target thickness of the flat conductive composite fiber for sofas. S5 stretch forming: The calendered composite strip is stretched unidirectionally with a stretch ratio of 1.5 to 4 times, a stretching temperature range of 80℃ to 200℃, and a stretching force range of 0.5N to 5N. S6 Sintering and Shaping: The stretched composite strip is sintered at 210℃-280℃ for 20min-60min to allow the extrusion aid to volatilize and the polytetrafluoroethylene to be shaped, resulting in a flat composite strip. S7 Slitting: The flat composite strip is slit along its length into flat conductive composite fibers.

5. The method for preparing a flat conductive composite fiber for sofas according to claim 4, characterized in that: The extrusion aid is selected from at least one of the following: paraffin oil, petroleum ether, citric acid and guar gum powder; The mixing process uses a high-speed mixer with a mixing rate of 500 rpm to 2000 rpm and a mixing time of 20 min to 60 min.

6. The method for preparing a flat conductive composite fiber for sofas according to claim 4, characterized in that: Preforming is performed using a plunger-type preforming machine, with a preforming pressure of 1 MPa-5 MPa. The extrusion temperature of the plunger extrusion is 25℃-60℃, the extrusion rate is 1mm / second-10mm / second, and the width of the extruded strip precursor is 1mm-10mm, and the thickness is 0.1mm-1mm.

7. The method for preparing a flat conductive composite fiber for sofas according to claim 4, characterized in that: In the calendering and compounding process, the roll surface temperature of the twin-roll calender is 60℃-120℃, and the calendering rate is 0.5m / min-5m / min; Pre-positioning is achieved by a guide roller and a limiting baffle set at the entrance of the calender. The limiting baffle is used to limit the position of the conductive reinforcement layer in the width direction.

8. The method for preparing a flat conductive composite fiber for sofas according to claim 4, characterized in that: Uniaxial stretching is performed using a multi-roll stretching machine with a stretching temperature of 100℃-180℃ and a stretching ratio of 2-3.5 times. The width of the stretched composite strip is 1mm-5mm, and the thickness is 15µm-100µm.

9. The method for preparing a flat conductive composite fiber for sofas according to claim 4, characterized in that: The slitting process uses a rotary blade slitting machine or a laser slitting machine, with a slitting width of 200µm-2000µm. The resulting flat conductive composite fiber for sofas has right-angled or rounded edges after heat setting.

10. The application of a flat conductive composite fiber for sofas, specifically the application of the flat conductive composite fiber for sofas according to any one of claims 1-3 or the flat conductive composite fiber for sofas prepared by the method according to any one of claims 4-9 in the preparation of industrial textiles, characterized in that... include: Industrial textiles include electromagnetic shielding fabrics, antistatic industrial filter cloths, sofa fabrics, radiation-proof tarpaulins, or signal-shielding curtains.

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