Preparation method of composite carpet with formaldehyde removal function and multi-layer composite carpet

Abstract

The invention discloses a preparation method of a composite carpet with a formaldehyde removal function and a multi-layer composite carpet. The preparation method comprises the following steps: preparing bottom-layer base cloth and surface-layer fabric; preparing and functionalizing a polyurethane microporous membrane as a middle barrier regulation and control layer; preparing a functional composite layer base material containing activated carbon nanoparticles; coating a functional composite layer base material with high activated carbon content to form a bottom reinforced adsorption layer, and laminating, hot-pressing and compounding the bottom reinforced adsorption layer, the bottom layer base cloth and the middle barrier regulation layer to obtain a three-layer primary complex; the three-layer initial complex is subjected to chitosan deep loading treatment through a bump spraying device, the device comprises a complex conveying system, a bump forming system and a chitosan applying system, and chitosan spraying guns synchronously move and are aligned with the bump part to spray a chitosan solution, so that chitosan deeply permeates into the interior along a bump interface; and compounding the surface rapid capture layer and the surface fabric subjected to functional finishing to obtain the five-layer composite carpet.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of functional textiles, and particularly relates to a preparation method of a multi-layer composite carpet with formaldehyde removal function and a multi-layer composite carpet prepared by the method. BACKGROUND

[0002] At present, the carpet products with formaldehyde removal function mainly adopt the following technical routes: The first is to add functional materials in the carpet fibers. For example, active carbon powder, zeolite or diatomite and other adsorbent materials are mixed in the fiber raw materials to prepare functional fibers through the spinning process, and then the functional fibers are woven into carpets. The advantage of this method is that the functional materials are firmly combined with the fibers and are not easy to fall off. However, the disadvantage is also obvious: the functional materials are wrapped inside the fibers, and the contact area with formaldehyde in the air is limited, so the adsorption efficiency is low; the addition amount is limited by the spinning process, and usually does not exceed 10%, which is difficult to meet the demand of high-efficiency formaldehyde removal; the black active carbon powder will affect the color and luster of the fibers and the carpet.

[0003] The second is to perform functional finishing on the surface of the carpet. For example, active carbon slurry, nano-TiO2 photocatalyst or chitosan and other functional materials are applied on the surface layer of the carpet by dipping, coating or spraying. The advantage of this method is that the process is simple, the functional materials are in direct contact with the air, and the formaldehyde removal effect is good. However, the disadvantage is that: the functional materials coated on the surface of the carpet are easy to be covered with dust or worn off, and the function is not durable; dark-colored materials such as active carbon will seriously affect the appearance of the carpet, especially the light-colored carpet products cannot use this method; the surface coating will also affect the hand feeling and air permeability of the carpet.

[0004] Chitosan is a natural polymer material, which contains a large number of amino (-NH2) and hydroxyl (-OH) groups in the molecular chain, and can react with formaldehyde molecules to form stable Schiff base or hemiacetal structure, realize chemical fixation of formaldehyde, and avoid secondary release. Therefore, chitosan is considered as an ideal formaldehyde removal material. However, in the prior art, the application of chitosan in carpet products mainly adopts the surface coating method, which has the problems of appearance pollution and poor function durability. How to load chitosan into the interior of the carpet in deep layer while maintaining clean appearance and realizing high-efficiency formaldehyde removal function is a technical problem to be solved in the field. SUMMARY

[0005] The purpose of the present application is to provide a preparation method of a multi-layer composite carpet with formaldehyde removal function, which loads chitosan solution into the interior of the carpet in deep layer by means of raised spraying technology, combines with the gradient distribution of active carbon nanoparticles, constructs a synergistic formaldehyde removal system of physical adsorption-chemical fixation-photocatalytic degradation, and realizes the technical effect that the functional materials are enriched in the interior of the carpet while the surface layer remains clean and beautiful.

[0006] To achieve the above object, the present application adopts the following technical solutions: A preparation method of a multi-layer composite carpet with formaldehyde removal function, comprising the following steps: Step one, preparing a bottom base cloth and a surface fabric; Step two, preparing an intermediate barrier regulation layer: selecting a polyurethane microporous membrane as the intermediate barrier regulation layer; Step three, preparing a functional composite layer base material: dispersing activated carbon nanoparticles in an adhesive to prepare a functional composite layer base material; Step four, forming a three-layer initial composite: coating the functional composite layer base material with high activated carbon content to form a bottom reinforced adsorption layer; stacking and hot-pressing the bottom base cloth, the bottom reinforced adsorption layer, and the intermediate barrier regulation layer in order to obtain a three-layer initial composite; Step five, deep loading of chitosan solution: using a raised spraying device to perform deep loading of chitosan on the three-layer initial composite, the raised spraying device comprising: A composite conveying system for conveying the three-layer initial composite and applying pressure to it; A raised forming system comprising a moving frame that can move back and forth along the width direction and a jacking rod assembly installed on the moving frame; the jacking rod assembly can apply force upward from the bottom surface of the three-layer initial composite, causing the initial composite to locally rise at the contact point; A chitosan application system comprising a chitosan spray gun, which moves synchronously with the moving frame and sprays chitosan solution at the raised part; Step six, a composite surface rapid capture layer: coating the functional composite layer base material with low activated carbon content to form a surface rapid capture layer; combining the surface rapid capture layer with the three-layer initial composite treated in step five to obtain a four-layer composite; Step seven, functional finishing of the surface fabric; Step eight, final compounding: combining the surface fabric finished in step seven with the four-layer composite to obtain a five-layer composite carpet.

[0007] Further, the specific process of the deep loading of chitosan in step five is as follows: the moving frame drives the jacking rod assembly to move along the width direction, the jacking rod assembly lifts the initial composite from the bottom surface to cause it to locally rise, the chitosan spray gun moves synchronously and sprays chitosan solution at the raised part, and the chitosan solution penetrates into the interior of the initial composite along the raised interface; after the moving frame completes the lateral movement, the initial composite is pushed forward, the moving frame returns to the starting point, and the above process is repeated to complete the loading of chitosan on the entire initial composite.

[0008] Further, the functionalization treatment of the polyurethane microporous membrane in step two comprises: plasma activation of the polyurethane microporous membrane, then dipping in a chitosan solution and drying to form a pre-coated chitosan bottom layer.

[0009] Further, after mixing the activated carbon nanoparticles with the non-ionic surfactant in step three, the activated carbon slurry is prepared by high-speed shearing or ultrasonic dispersion, and then mixed with the binder to form the functional composite layer base material.

[0010] Further, the hot pressing in step four comprises a preheating stage, a hot pressing stage and a cooling stage; and the same hot pressing process is used for the combination of the surface rapid capture layer and the three-layer preliminary composite in step six.

[0011] Further, in step five, before the chitosan deep loading treatment, the preliminary composite is locally relaxed by adjusting the actions of the transmission traction roller and the transmission push roller, so as to provide a margin for the bulge.

[0012] Further, in step five, the three-layer preliminary composite subjected to the bulge spraying treatment is subjected to low-temperature drying, so that the water in the chitosan solution is volatilized and solidified into a film at the interface.

[0013] Further, the activated carbon nanoparticles have a particle size of 50-150 nm and a specific surface area of ≥1000 m² / g.

[0014] Further, in step one, the bottom base cloth is woven by adding activated carbon powder to the fiber raw material before weaving, and then woven by using functional fibers prepared by a melt spinning or blending process.

[0015] Further, in step seven, the functional finishing comprises: sequentially performing nano-TiO2 photocatalytic finishing and fluorocarbon waterproof and stain-resistant finishing on the surface fabric.

[0016] The application also provides a multi-layer composite carpet with formaldehyde removal function prepared by the above preparation method.

[0017] The application has the following advantages: (1) By locally lifting from the bottom of the carpet, the composite forms a conical bulge, the interface between the layers is expanded, the chitosan solution penetrates along the interface of the bulge in a directional deep layer, and is mainly enriched in the interface region between the middle barrier control layer and the bottom reinforced adsorption layer, realizing the deep layer distribution of the functional material, and the surface remains relatively clean, solving the technical problems of difficult deep layer loading of the functional material and affecting the appearance in the traditional method.

[0018] (2) Constructing high-efficiency adsorption system by gradient distribution of activated carbon nanoparticles: high-concentration activated carbon nanoparticles are used as the main adsorption zone in the bottom reinforced adsorption layer, and low-concentration activated carbon nanoparticles are used to realize rapid capture in the surface rapid capture layer, forming a gradient adsorption system of "surface rapid capture-bottom reinforced locking", which significantly improves the capture efficiency and adsorption capacity of formaldehyde.

[0019] (3) Triple synergistic removal of formaldehyde by physical adsorption-chemical fixation-photocatalytic degradation: activated carbon nanoparticles provide physical adsorption, the amino groups of chitosan realize chemical fixation, and the TiO2 coating on the surface layer performs photocatalytic degradation, and the three mechanisms work synergistically to achieve persistent and efficient removal of indoor formaldehyde.

[0020] (4) Buffering and intercepting the intermediate barrier control layer to prevent reverse release: the polyurethane microporous membrane as the intermediate layer, after functionalization treatment with chitosan, can not only buffer the speed of formaldehyde transmission downward, but also intercept the reverse release of adsorbed formaldehyde, while maintaining the softness and air permeability of the carpet.

[0021] (5) Simple process easy for industrial production: the raised spraying device can be integrated into the existing carpet production line, and through transverse continuous spraying and longitudinal intermittent advancement, automatic continuous processing of full-width carpet is realized, the process is stable and controllable, and is suitable for large-scale industrial production.

[0022] (6) Product appearance and function: the functional materials are mainly enriched in the interior of the carpet, the surface fabric remains clean and beautiful, and at the same time has the functions of waterproof, stain-proof and photocatalytic self-cleaning, which not only meets the functional requirements of formaldehyde removal, but also ensures the decorative and practicality of the product. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 is a schematic diagram of the structure section of the multi-layer composite carpet of the present application; Figure 2 is a schematic diagram of the cross-sectional structure of the preparation device of the raised forming system of the present application; Figure 3 is Figure 2 is a local enlarged view of the middle A, showing the detailed structure of the raised forming system inside the middle fixing roller, including the detailed schematic diagram of the intermediate barrier control layer; Figure 4 is a schematic diagram of the preparation process flow of the multi-layer composite carpet; Figure 5 is Figure 3 is a further application state diagram based on the above, i.e. the raised state of the knitted carpet during operation and the process of spraying the antibacterial agent.

[0024] REFERENCE NUMERALS: Three-layer primary composite 01, base cloth layer 10, bottom reinforced adsorption layer 20, intermediate barrier regulation layer 30, surface rapid capture layer 40, surface fabric 50, raised forming system 60, guide rail 61, moving frame 62, synchronous belt transmission mechanism 63, synchronous belt 631, lifting drive mechanism 65, jacking rod assembly 66, jacking rod 661, force transmission joint 662, transmission traction roller 70, transmission push roller 80, intermediate fixed roller 90, first compression roller 91, second compression roller 92, long slot 93, fixed guide shaft 94, reinforcing spoke 95, chitosan spraying device 100, chitosan spray gun 101. DETAILED DESCRIPTION

[0025] As shown in the embodiment, a multi-layer composite carpet with formaldehyde removal and odor removal functions is provided, which comprises: a base cloth layer 10 located at the bottom to provide structural support and preliminary adsorption, a bottom reinforced adsorption layer 20 containing high-concentration activated carbon nanoparticles to form a main adsorption area, an intermediate barrier regulation layer 30 for buffering transmission and blocking reverse release, a surface rapid capture layer 40 containing moderate activated carbon nanoparticles to achieve rapid capture, and a surface fabric 50 with photocatalytic and protective finishing to maintain clean appearance. Figure 1 The technical core of the embodiment is that the gradient distribution of activated carbon nanoparticles in the bottom reinforced adsorption layer 20 and the surface rapid capture layer 40 is combined with the deep loading of chitosan solution to the interior of the carpet through the raised spraying process, to construct a synergistic formaldehyde removal system of "physical adsorption (activated carbon)-chemical fixation (chitosan)-deep enrichment (raised spraying)". The functional materials are mainly enriched in the bottom reinforced adsorption layer 20 and the intermediate barrier regulation layer 30 area of the carpet interior, and the surface fabric 50 remains relatively clean.

[0026] I. Carpet structure and functional mechanism

[0027] 1) Gradient adsorption system of activated carbon nanoparticles The adhesive layer matrix of the bottom reinforced adsorption layer 20 and the surface rapid capture layer 40 uniformly disperses activated carbon nanoparticles with a particle size of 50-150 nm and a specific surface area of ≥1000 m² / g. Activated carbon nanoparticles can be uniformly distributed in the inner layer through conventional coating-composite process, but their black appearance determines that they must be "hidden" in the interior of the carpet, which is the key problem to be solved by the subsequent raised spraying process: to ensure the deep distribution of activated carbon while maintaining the cleanliness and beauty of the surface layer.

[0028] ​2) The formation mechanism of the chitosan deep functional coating. Chitosan solution (degree of deacetylation ≥ 85%, molecular weight 10-30 million) is loaded into the interior of the carpet by using the bump spraying process. The principle of bump spraying is: by partially lifting from the bottom of the carpet, a conical bump is formed at the lifting point, the fabric structure is deformed in three dimensions in the bump area, the fiber gap is expanded, and the composite layer interface is stretched; at this time, chitosan solution is sprayed from above, the solution penetrates along the inclined surface of the bump and the expanded interface, and is mainly enriched in the middle barrier control layer 30 and the bottom adsorption enhancement layer 20. The functional coating is formed in these internal interfaces.

[0029] 3) Buffering and intercepting function of the middle barrier control layer 30. The middle barrier control layer 30 is made of polyurethane microporous membrane, with a thickness of 0.12-0.20 mm and a pore size of 6-10 μm.

[0030] 4) Auxiliary function of the base fabric layer 10 and the surface fabric 50. The base fabric layer 10 is made by knitting or weaving process. The natural pores of the woven structure provide channels for gas flow, supporting the transfer of formaldehyde molecules from the surface layer to the inner layer. To further enhance the adsorption capacity of the bottom layer, activated carbon powder (particle size 5-20 μm, addition amount 5-10%) can be added to the fiber raw material, and then functional fibers are prepared by melt spinning or blending process and knitted to form the final adsorption barrier. The surface fabric 50 is made of tufted carpet fabric or knitted fabric, with a surface density of 400-600 g / m². The surface layer is subjected to nano-TiO2 photocatalytic finishing (coating amount 10-15 g / m²) and fluorocarbon waterproof and stain-resistant finishing. The TiO2 coating (anatase type or visible light responsive type modified by nitrogen doping) has photocatalytic activity under indoor scattered light, which can catalytically degrade the formaldehyde contacting the surface layer into CO2 and H2O, serving as the "first line of defense" for formaldehyde removal. The fluorocarbon finishing makes the surface layer have waterproof and stain-resistant functions (hydrostatic pressure ≥ 10 kPa, stain-resistant grade ≥ 4), while maintaining the air permeability (air permeability ≥ 2500 g / m²·24h), which does not hinder the transfer of formaldehyde to the inner layer.

[0031] 5) Five-layer synergistic formaldehyde removal mechanism The formaldehyde molecules in the indoor air first contact the surface fabric 50, part of which is photocatalytically degraded by TiO2; the remaining formaldehyde penetrates the surface fabric into the surface rapid capture layer 40, which is rapidly physically adsorbed by the active carbon nanoparticles of moderate concentration, and is chemically fixed by the chitosan coating (a small amount of which is attached by raised spraying); the formaldehyde that is not completely captured continues to pass downward, and when it passes through the intermediate barrier regulation layer 30, the transmission speed is buffered, and the chitosan coating on the membrane surface and the inner wall of the pore intercepts it; then it enters the bottom enhanced adsorption layer 20, where it is finally locked by the high-concentration active carbon nanoparticles and the deep-layer enriched chitosan coating; a small amount of formaldehyde that reaches the base fabric layer 10 is adsorbed by the active carbon (if any is added) in the bottom layer of fibers. Through the five-level synergistic mechanism of "surface layer photocatalytic preliminary degradation → surface layer rapid adsorption and fixation → intermediate layer buffering and interception → bottom layer enhanced capture and locking → base fabric layer final barrier", the indoor formaldehyde is removed persistently.

[0032] II. Preparation process The core of the preparation process of the present embodiment lies in the combined application of two technologies: uniform dispersion and composite technology of active carbon nanoparticles and raised deep-layer loading technology of chitosan solution.

[0033] First step: preparation of bottom base fabric 10 and surface fabric 50 The bottom base fabric 10 is prepared by knitting or weaving process, with a surface density of 200-250 g / m². If the adsorption capacity of the bottom layer needs to be enhanced, active carbon powder (particle size 5-20 μm, addition amount 5-10%) can be added to the fiber raw material before weaving, and functional fibers are prepared by melt spinning or blending process, and then the bottom base fabric is woven. The surface fabric 50 uses tufted carpet fabric or knitted fabric.

[0034] Second step: preparation and functionalization of intermediate barrier regulation layer 30 The intermediate barrier regulation layer 30 is made of polyurethane microporous membrane (thickness 0.12-0.20 mm, pore size 6-10 μm), which is prepared by thermal induced phase separation method or wet phase inversion method. The functionalization process includes two steps: (1) plasma activation, using oxygen or air plasma treatment (power 100-200 W, 30-60 seconds), introducing active groups such as hydroxyl and carboxyl groups on the membrane surface and pore wall. (2) Pre-coat chitosan bottom layer, immerse the activated microporous membrane in low-concentration chitosan solution (concentration 5-8 g / L), immerse for 3-5 minutes, then take out and dry (80-100°C, 5-8 minutes). This step forms a thin chitosan bottom layer (coating amount about 2-3 g / m²) on the membrane surface, which has two functions: providing preliminary amino functional groups; improving the hydrophilicity of the membrane, facilitating the penetration of chitosan solution during subsequent raised spraying.

[0035] Third step: Preparation of functional composite layer matrix material The functional composite layer matrix material is prepared with modified polyurethane adhesive as the matrix, in which activated carbon nanoparticles and necessary additives are uniformly dispersed. Activated carbon nanoparticles tend to agglomerate due to van der Waals forces, so pre-dispersion treatment is necessary. Mix activated carbon nanoparticles with non-ionic surfactant (as dispersant), and use high-speed shearing or ultrasonic dispersion to prepare high-concentration activated carbon slurry. The purpose of pre-dispersion is to break the agglomeration and improve the uniformity and stability of dispersion in the adhesive. Then add conventional additives to prepare a uniform functional composite layer matrix material. The formulation varies: the activated carbon content in the bottom reinforced adsorption layer 20 (near the bottom layer) is higher, and the activated carbon content in the surface rapid capture layer 40 (near the surface layer) is slightly lower.

[0036] Fourth step: Preliminary lamination and compounding First, form the bottom reinforced adsorption layer 20: Apply the functional composite layer matrix material (formulation with higher activated carbon content) to the release paper or PET release film by blade coating or roller coating, with a coating amount of 40-45 g / m². After coating, pre-dry at room temperature for 10-20 minutes to partially volatilize the solvent and make the adhesive layer semi-solid. Then perform three-layer preliminary lamination, accurately align and stack in the following order: bottom layer base cloth 10, middle layer bottom reinforced adsorption layer 20 (coated on release material, adhesive side up), top layer intermediate barrier control layer 30 (functionalized microporous membrane). Ensure accurate alignment of each layer during lamination to avoid offset, wrinkles or bubbles. Next, perform hot press compounding: feed the stacked three-layer fabric into the hot press compounding device, which includes a preheating roller group, a heating and pressing roller group, and a cooling roller group. Preheating stage: roller temperature 55-65°C, pressure 0.12-0.18 MPa, passing time 8-12 seconds, which serves to preliminarily soften the adhesive layer and expel interlayer gas. Hot pressing stage: heating and pressing roller temperature 80-90°C, pressure 0.9-1.1 MPa, passing time 12-16 seconds. Cooling stage: cooling roller temperature 20-25°C, pressure 0.3-0.5 MPa, passing time 10-14 seconds, which serves to quickly solidify the adhesive layer and lock the bonding structure. After hot press compounding, a three-layer preliminary composite (bottom layer base cloth 10 + bottom reinforced adsorption layer 20 + intermediate barrier control layer 30) is obtained, and the final thickness of the bottom reinforced adsorption layer is 70-100 μm.

[0037] Fifth step: Deep loading of chitosan solution into the raised area This step uses a special raised spraying device to load chitosan solution into the interior of the three-layer preliminary composite 01. The device is integrated into the carpet production line and mainly includes a composite transmission system, a raised forming system 60, and a chitosan application system.

[0038] (1) The structure and function of the composite transmission system The three-layer primary composite (bottom base cloth 10 + bottom reinforced adsorption layer 20 + middle barrier regulation layer 30) is transported along the horizontal direction. The transmission system includes: the transmission traction roller 70 is located at the front end of the device, responsible for pulling the primary composite from the upstream station to the bulging spraying station; the transmission push roller 80 is located at the rear end of the device, responsible for pushing the processed composite to the downstream station; the middle fixed roller 90 is arranged at the central position between the transmission traction roller 70 and the transmission push roller 80, and the primary composite passes above the middle fixed roller 90; the first compression roller 91 and the second compression roller 92 are located above the primary composite, and the primary composite is subjected to compression force to ensure that it is closely attached to the middle fixed roller 90. The middle fixed roller 90 adopts a hollow roller body structure, which is the key design to realize the bulging spraying. A long slot 93 is formed on the roller body wall in the axial direction, and the length of the long slot 93 covers the entire effective working width (usually 1.5-3.0 meters) within the movement stroke range of the moving frame 62. The two edges of the long slot 93 are provided with detachable fixed guide shafts 94, which have two functions: guiding the lifting movement of the lifting rod assembly 66 to ensure the vertical stability of the movement track; preventing the primary composite from falling into the slot and maintaining the flat state of the composite. Since the middle fixed roller 90 is provided with the long slot 93, in order to ensure the rigidity of the roller body, a plurality of reinforcing spokes 95 are arranged inside the hollow roller body. These spokes extend radially from the roller body center to the inner wall of the roller body, forming a support skeleton. The reinforcing spokes 95 ensure that the hollow roller body does not deform when bearing the weight of the primary composite and the lifting force, and are preferably made of steel material, with 4-8 evenly distributed to avoid blocking the movement space of the long slot 93 area and the internal bulging mechanism.

[0039] As a further preferred solution, the intermediate fixed roller 90 has a rotation adjustment and angle locking function. The two end bearing seats of the intermediate fixed roller 90 are rotatably mounted, the roller body can rotate to any angle within ±180° range around its own axis, an angle scale dial and locking mechanism (such as a gear locking device or an electromagnetic brake) are arranged at one end of the roller body. The advantages of this function include: by rotating the intermediate fixed roller 90, the position of the long groove 93 relative to the primary and secondary composite body can be changed, thereby adjusting the relative position of the action point of the jack assembly 66 on the cross section of the composite body (towards the base fabric layer, centered or towards the microporous membrane layer); rotating the roller body can change the direction of the jacking force, adjusting the bulging shape from positive jacking (perpendicular direction) to oblique jacking (at a certain angle with the surface of the composite body), to adapt to different chitosan penetration requirements. For thick and heavy carpets, the angle of oblique jacking can be adjusted to a larger angle to increase the expansion range of the interlayer interface, facilitating deep penetration of chitosan solution; for light and thin carpets, a smaller angle of gentle jacking is used to avoid excessive stretching and damage to the adhesive layer or fibers; for different material composites, by adjusting the position and angle of the bulging point, the elastic modulus and deformation characteristics of different materials can be matched. In different areas of the same carpet, angle adjustment can also achieve local intensive treatment or light treatment to meet the functional zoning requirements (such as increasing chitosan load in high contact areas). During operation, when the process is adjusted, the operator loosens the locking mechanism, manually or electrically rotates the roller body to the target angle, and locks it after reading the scale dial. Angle adjustment is usually performed when changing product specifications or process parameters, and the locking state is maintained during normal production process.

[0040] (2) The composition and working principle of the bulging forming system 60 The bulging forming system 60 is completely installed inside the hollow roller body of the middle fixed roller 90, and is the core mechanism for realizing local bulging. The system includes the following components: the guide rail 61 extends along the axial direction of the middle fixed roller 90, is fixed on the inner wall of the roller body or the reinforcing spokes 95, and provides a movement track for the moving frame 62. The guide rail 61 preferably adopts a linear guide rail or a slide rail structure to ensure the movement accuracy of the moving frame 62. The moving frame 62 cooperates with the guide rail 61 through a linear slide block to ensure stable movement without shaking. The moving frame 62 is made of lightweight high-strength aluminum alloy or engineering plastic to reduce inertial load and improve movement response speed. The synchronous belt driving mechanism 63 includes a synchronous belt 631, the two ends of which are respectively fixed on fixed points (usually synchronous pulleys) at both ends of the roller body, and the middle part is fixedly connected with the moving frame 62. A servo motor or a stepping motor (installed on a fixed support outside the roller body) is used as the driving motor, which drives the synchronous pulley to rotate through a speed reducer, drives the synchronous belt 631 to move, and then drives the moving frame 62 to move along the guide rail 61 in a reciprocating straight line. The lifting driving mechanism 65 is installed on the moving frame 62, and is preferably a pneumatic cylinder or an electric push rod. Its function is to accurately control the extension height of the jacking rod assembly 66, so as to adjust the bulging amplitude. The jacking rod assembly 66 includes a jacking rod 661 and a force transmission joint 662. The jacking rod 661 is a cylindrical or conical rod body with a diameter of 8-15 mm and is made of stainless steel or hard aluminum alloy. The force transmission joint 662 preferably adopts a roller structure with a diameter of 15-30 mm and is made of polyurethane or rubber-coated metal core. The key advantage of selecting a roller as the force transmission joint 662 is that the contact area is moderate, which can provide sufficient support force and avoid stress concentration caused by point contact. The roller can freely roll with the lateral movement of the moving frame 62 when it contacts the bottom surface of the primary composite, forming rolling contact instead of sliding friction, which effectively avoids dragging damage, fiber tearing or adhesive layer peeling of the bottom of the primary composite (the bottom base cloth 10).

[0041] The working principle is as follows: The lifting driving mechanism 65 adjusts the jacking rod assembly 66 to a preset height (usually the bulging height is 5-15 mm) and keeps the height unchanged. When the moving frame 62 driving system starts, the moving frame 62 drives the jacking rod assembly 66 to move along the guide rail 61. The roller-shaped force transmission joint 662 enters the working area from the starting point of the primary composite, the jacking rod 661 passes through the long slot 93 of the middle fixed roller 90, and the force transmission joint 662 lifts the primary composite from the bottom surface, so that the composite is in a local bulging state.

[0042] (3) The chitosan application system is arranged above the first and second compression rollers 91 and 92, and is provided with a chitosan spraying device 100. The device comprises a chitosan spray gun 101 mounted on an adjustable angle universal support, the height of the nozzle from the surface of the primary composite can be adjusted within a range of 80-150 mm, an ultrasonic atomizing nozzle or a pneumatic atomizing nozzle is adopted to ensure that the chitosan solution forms fine and uniform mist droplets (particle size 20-50 μm), and the spraying angle can be adjusted within a range of ±30° vertically downward to match different angles of the protrusions. The chitosan liquid supply system comprises a liquid storage tank (capacity 20-50 L, with liquid level monitoring and heating and insulation functions, maintaining the solution temperature at 25-35°C to ensure the stability of the viscosity of the chitosan solution), a metering pump (a precision plunger pump or a peristaltic pump), a pressure regulating valve (maintaining the spraying pressure at 0.2-0.6 MPa), a flow controller (real-time monitoring and feedback of the flow), and a filtering device (an online filter with a precision of 5-10 μm to prevent impurities from blocking the nozzle). The synchronous following mechanism ensures that the chitosan spray gun 101 is always aligned with the protrusion part. The chitosan spray gun 101 is fixed on an external moving support, which is synchronized with the moving frame 62 in one of the following ways: scheme A is to synchronize through a driving source, that is, the external moving support is driven by an independent servo motor, the motor and the driving motor of the moving frame 62 are synchronized through a PLC (programmable logic controller) or a motion controller; scheme B is a mechanical linkage mode, which synchronizes the external moving support with the moving frame 62 through a coaxial synchronous belt or a gear and rack transmission; scheme C is an optical servo mechanism, which detects the position of the moving frame 62 in real time through a laser displacement sensor, and the driving system of the external moving support realizes dynamic following according to the position feedback. No matter which scheme is adopted, the chitosan spray gun 101 is always aligned with the protrusion part, and the following accuracy reaches ±2 mm.The importance of this tension adjustment is to ensure that the primary composite can fully bulge (bulge height 5-15 mm) when the jacking rod assembly 66 is in action without being restricted by excessive tension; to avoid the adhesive layer 20 from cracking or delaminating due to excessive stretching during bulging; to ensure that the pore structure of the intermediate barrier control layer 30 (polyurethane microporous membrane) is not damaged during deformation. Step 3-4: Bulging device in place and continuous bulging spraying The moving frame 62 is driven by the synchronous belt 631, which drives the jacking rod assembly 66 to move to the starting processing position of the primary composite width (usually 50-100 mm from the edge). The lifting drive mechanism 65 has been pre-adjusted to the preset working height, so that the roller-shaped force connector 662 is in standby state, and the top end is about 2-5 mm away from the bottom surface of the primary composite. Then enter the core step of deep loading of chitosan: the moving frame 62 driving system starts to move at a constant speed (10-30 mm / s) along the width direction, the jacking rod 661 passes through the long slot 93 of the intermediate fixed roller 90, and the roller-shaped force connector 662 exerts force upward from the bottom surface of the primary composite, causing the composite to locally bulge at the contact point. The primary composite presents a conical bulge (bulge height 5-15 mm, cone angle 30-60°) at the jacking point, and each layer deforms cooperatively: the intermediate barrier control layer 30 (polyurethane microporous membrane) bends at the bulging apex, the pores are stretched and opened, the effective pore size is expanded from 6-10 μm to 8-12 μm, forming a "high permeability window period"; the bottom reinforced adsorption layer 20 (adhesive layer) elastically deforms in the bulging area, the interface between the adhesive layer matrix and the microporous membrane 30 is opened, forming gaps (width 10-50 μm), which are the target penetration channels for chitosan solution; the bottom base cloth 10 is radially stretched around the jacking point, and the interlaced fiber gap is increased, providing a channel for chitosan to penetrate into the bottom layer. The chitosan spray gun 101 follows the movement synchronously, and the nozzle is always aimed at the bulging apex area (alignment accuracy ± 2 mm), continuously spraying atomized chitosan solution (concentration 15-25 g / L, spraying flow 100-300 mL / min). Because the primary composite is in a bulging state, the chitosan droplets do not directly settle on the flat surface layer, but undergo directional deep penetration: the droplets slide down the inclined surface of the bulge under the action of gravity and capillary force, and enter the interlayer interface; mainly enriched (coating amount 10-20 g / m²) at the interface between the intermediate barrier control layer 30 and the bottom reinforced adsorption layer 20, forming a functional coating; part of the chitosan solution continues to penetrate downward through the pores of the microporous membrane 30 that are stretched, reaching the inside of the bottom reinforced adsorption layer 20 (coating amount 5-10 g / m²); a small amount of chitosan solution penetrates to the bottom base cloth 10, forming a thin coating layer (coating amount 2-5 g / m²) on the fiber surface, achieving the final locking. In contrast, the surface layer (the upper surface of the intermediate barrier control layer 30) is at the top of the bulge, only a small amount of chitosan droplets adhere (coating amount <2 g / m²), and most of them remain clean.The roller-shaped force transmission joint 662 freely rotates during movement, forming rolling contact with the bottom surface of the primary composite rather than sliding friction, with contact pressure controlled at 50-100 kPa and rolling friction coefficient <0.1, effectively avoiding drag damage to the bottom base cloth 10 and ensuring that the base cloth remains intact. Steps 5-8: Complete processing and cycle The moving frame 62 continues to move until it reaches the end position of the primary composite width (usually 50-100 mm from the other edge), and after completing the entire width of the chitosan application, the moving frame 62 stops moving and the chitosan spray gun 101 stops spraying. After the processing is completed, the lifting drive mechanism 65 can optionally lower the lifting rod assembly 66 slightly (by 2-3 mm) or maintain the original height. The primary composite recovers to a flat state under the combined action of its own elastic recovery force (the elastic modulus of the microporous membrane 30 and the adhesive layer 20), the pressure of the pressure roller (the holding force of the first pressure roller 91 and the second pressure roller 92 is 50-100 N / cm), and the material tension. Due to the uniform stress distribution during the bulging process (the conical bulging causes the stress to be radiated) and the short action time (single-point bulging time <2 seconds), the primary composite layers do not undergo permanent deformation, and there are no creases or delamination on the surface. The transmission traction roller 70 and the transmission push roller 80 are started synchronously to advance the primary composite by one longitudinal step (step 10-30 mm, adjusted according to the coverage requirement), so that the new area that has not been processed enters the working position. The moving frame 62 returns to the starting position of the width through the synchronous belt 631 transmission system at a high speed (return speed 50-100 mm / s, which is 2-3 times the spraying speed), preparing for the processing of the next row. Repeat the above steps to complete the chitosan loading of the entire primary composite row by row. Through the cooperation of transverse continuous spraying (row spacing 10-30 mm) and longitudinal intermittent advancement, full coverage processing of the entire primary composite is realized, and the chitosan forms a uniform three-dimensional distribution network inside the composite, mainly enriched in the interface region between the middle barrier control layer 30 and the bottom reinforcement adsorption layer 20. The three-layer primary composite that has undergone bulging and spraying is sent out of the bulging and spraying station by the transmission push roller 80 and enters the drying and curing area. A hot air circulating oven or infrared drying device is used for low-temperature drying, with a temperature control of 80-100°C and a drying time of 5-8 minutes. The water in the chitosan solution evaporates, and the chitosan molecular chain solidifies into a film on the interface and the inner wall of the pore, forming a stable functional coating; the adhesive in the adhesive layer 20 is completely cured during this process (if it was not completely cured during the fourth step of compounding).

[0043] Sixth step: compounding of the surface rapid capture layer 40 Coating surface rapid capture layer: coat low activated carbon content formula on the release material (coating amount 30-35 g / m²), pre-dry for 10-20 minutes. Four-layer composite: composite the treated three-layer primary composite (bottom base cloth 10 + bottom reinforced adsorption layer 20 + middle barrier regulation layer 30) with the surface rapid capture layer 40, the composite surface is the upper surface of the middle barrier regulation layer 30. Hot pressing parameters: the same as the fourth step, to obtain a four-layer composite.

[0044] Seventh step: functional finishing of surface layer fabric 50 TiO2 photocatalytic finishing: prepare nano-TiO2 slurry (anatase type or nitrogen-doped modified type, particle size 10-30 nm); impregnate or coat on the surface layer fabric 50, coating amount 10-15 g / m²; dry and cure (120-150°C, 3-5 minutes).

[0045] Fluorocarbon waterproof and stain-resistant finishing: Use fluorocarbon finishing agent (C6 or C8 series), coating amount 15-20 g / m²; dry and cure (140-160°C, 2-3 minutes); Final performance: hydrostatic pressure ≥10 kPa, stain resistance grade ≥4, air permeability ≥2500 g / m²·24h.

[0046] Eighth step: final composite and post-processing Five-layer composite: composite the finished surface layer fabric 50 with the four-layer composite, the composite surface is the upper surface of the surface rapid capture layer 40.

[0047] Post-processing: stand and relax for 24-48 hours to release internal stress, cut and finish to obtain the final five-layer composite carpet.

[0048] The above examples are only used to illustrate the technical solutions of the present application, but not to limit it. Those skilled in the art can make various modifications and changes under the inspiration of the technical solutions of the present application, as long as they are within the scope of the claims of the present application, which should belong to the protection scope of the present application.

Claims

1. A method for preparing a multi-layer composite carpet with formaldehyde removal function, characterized in that, Includes the following steps: Step 1: Prepare the base fabric (10) and the surface fabric (50); Step 2, Preparation of intermediate barrier control layer (30): Polyurethane microporous membrane is selected as intermediate barrier control layer (30); Step 3, preparing the functional composite layer matrix material: Disperse activated carbon nanoparticles in a binder to prepare the functional composite layer matrix material; Step 4, forming a three-layer primary composite: The functional composite layer matrix material with high activated carbon content is coated to form a bottom reinforced adsorption layer (20); the bottom base fabric (10), the bottom reinforced adsorption layer (20), and the middle barrier control layer (30) are stacked and hot-pressed in sequence to obtain a three-layer primary composite (01). Step 5, Chitosan Solution Raising Deep Loading: The three-layer primary composite (01) is subjected to chitosan deep loading treatment using a raising spraying device, which includes: A composite material transport system is used to transport and pressurize a three-layer primary composite material. The bulging molding system (60) includes a movable frame (62) that can reciprocate along the horizontal direction and a lifting rod assembly (66) mounted on the movable frame (62); the lifting rod assembly (66) can apply force upward from the bottom surface of the three-layer primary composite to cause the primary composite to bulge locally at the contact point; The chitosan application system includes a chitosan spray gun (101), which moves synchronously with the moving frame (62) and sprays chitosan solution onto the raised area; Step 6, composite surface rapid capture layer (40): a functional composite layer matrix material with low activated carbon content is coated to form a surface rapid capture layer (40); the surface rapid capture layer (40) is combined with the three-layer initial composite material after step 5 to obtain a four-layer composite material; Step 7: Perform functional finishing on the surface fabric (50); Step 8, final composite: The surface fabric (50) prepared in step 7 is combined with the four-layer composite to obtain a five-layer composite carpet.

2. The preparation method according to claim 1, characterized in that, The specific process of the deep loading treatment of chitosan in step five is as follows: the moving frame (62) drives the lifting rod assembly (66) to move along the horizontal direction. The lifting rod assembly (66) lifts the initial composite from the bottom surface to make it locally bulge. The chitosan spray gun (101) moves synchronously and sprays chitosan solution onto the bulging part. The chitosan solution penetrates deep into the interior of the initial composite along the bulging interface. After the moving frame (62) completes the lateral movement, the initial composite moves forward. The moving frame (62) returns to the starting point and repeats the above process to complete the chitosan loading of the entire initial composite.

3. The preparation method according to claim 1 or 2, characterized in that, The functionalization process described in step two includes: plasma activation of the polyurethane microporous membrane, followed by immersion in a chitosan solution and drying to form a pre-coated chitosan underlayer.

4. The preparation method according to claim 3, characterized in that, In step three, the activated carbon nanoparticles are mixed with nonionic surfactants and then dispersed by high-speed shearing or ultrasonication to form an activated carbon slurry, which is then mixed with a binder to form the functional composite layer matrix material.

5. The preparation method according to claim 4, characterized in that, The hot-pressing composite in step four includes a preheating stage, a hot-pressing stage, and a cooling stage; the composite of the surface rapid capture layer (40) and the three-layer primary composite in step six adopts the same hot-pressing process.

6. The preparation method according to claim 5, characterized in that, In step five, before performing the deep loading treatment of chitosan, the initial composite is partially relaxed by adjusting the movement of the transfer traction roller (70) and the transfer push roller (80) to provide margin for bulging.

7. The preparation method according to claim 6, characterized in that, In step five, the three-layer primary composite material that has undergone raised spraying treatment is dried at low temperature to allow the water in the chitosan solution to evaporate and solidify into a film at the interface.

8. The preparation method according to claim 1, characterized in that, The activated carbon nanoparticles have a particle size of 50-150 nm and a specific surface area of ​​≥1000 m² / g.

9. The preparation method according to claim 1, characterized in that, The bottom base fabric (10) mentioned in step one is made by adding activated carbon powder to the fiber raw material before weaving, and then weaving it into functional fibers through melt spinning or blending process.

10. A multi-layer composite carpet with formaldehyde removal function, characterized in that, include: The base fabric (10) is used to provide structural support; The bottom reinforced adsorption layer (20) is set above the bottom base fabric (10) and is composed of an adhesive layer containing high concentration of activated carbon nanoparticles; The intermediate barrier control layer (30) is disposed above the bottom enhanced adsorption layer (20) and is a polyurethane microporous membrane; A surface rapid capture layer (40) is disposed above the intermediate barrier control layer (30) and is composed of a binder layer containing activated carbon nanoparticles, wherein the concentration of activated carbon nanoparticles is lower than that of the bottom enhanced adsorption layer (20). Surface fabric (50) is disposed above surface fast capture layer (40); The interface region between the bottom enhanced adsorption layer (20) and the intermediate barrier control layer (30) and the interior of the intermediate barrier control layer (30) are loaded with a chitosan coating, which is formed by the preparation method described in claim 1.

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