Felt based on waste spinning article regeneration and preparation method thereof

Abstract

The invention relates to the field of waste textile recycling, in particular to a felt based on waste spinning article regeneration and a preparation method thereof.The preparation method of the felt based on waste spinning article regeneration comprises the steps that waste spinning articles and low-melting-point chemical fibers are cut up and mixed and then pressed and formed in a mold; the compression molding is performed in a pre-pressing stage, a hot pressing stage and a pressure maintaining and cooling stage; the mode of gradient pressure and balanced pressure is adopted, low-melting-point chemical fibers located in the center of the mold flow towards the edge after being molten, and the problem that when general hot pressing adopts global pressure equalizing, the edge density of felt is obviously lower than that of a central area due to the fact that heat loss is fast and pressure transmission is attenuated in the edge area of the mold is better solved; the prepared felt has certain strength and hardness, can meet the use requirements of the prop display board, and is good in density and uniformity.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of waste textile recycling, in particular to a felt based on waste textile and a preparation method thereof. BACKGROUND

[0002] There are various sources of waste textiles, mainly including: during the processing of clothes and raw materials, due to chemical operations and mechanical processing, waste cloth will inevitably be produced, such waste cloth has less pollution and relatively simple pretreatment process; waste clothes, carpets and bed sheets are the main sources of waste textiles, and the quantity is huge, which is time-consuming and laborious to recycle and process. However, regardless of which product, its recycling can save textile raw materials and reduce environmental pollution.

[0003] In order to increase the utilization of waste textiles, various recycling methods are adopted for waste textiles, such as physical recycling, chemical recycling and energy recycling; reprocessing fiber non-woven fabric is the most widely used field of fiber recycling and reuse, which includes felt made of waste textiles. The traditional waste textile regenerated felt is mainly made by mixing and pressing fiber scraps and thermoplastic adhesive, however, the conventional hot pressing adopts global uniform pressure, and the edge area of the mold has fast heat loss and pressure transmission attenuation, resulting in that the edge density of the felt is significantly lower than that of the center area, so that the edge area of the felt has insufficient hardness. SUMMARY

[0004] The purpose of the present application is to provide a felt based on waste textiles and a preparation method thereof, which better solves the problem that when the conventional hot pressing directly adopts global uniform pressure, the edge area of the mold has fast heat loss and pressure transmission attenuation, resulting in that the edge density of the felt is significantly lower than that of the center area, so that the prepared felt has certain strength and hardness, can meet the use requirements of prop display board, and the density and uniformity of the felt are good, and the surface is flat.

[0005] The technical scheme for achieving the purpose of the present application is: the present application has waste textiles and low-melting-point chemical fibers; comprising the following steps: S1, preparing waste textiles and low-melting-point chemical fibers; removing non-woven foreign matters from waste textiles containing natural fibers and / or synthetic fibers, and forming fragments through coarse crushing, and then obtaining fiber scraps after fine opening and dehydration; S2, cutting the low-melting-point chemical fibers; S3, stirring the low-melting-point chemical fibers and the fiber scraps in a stirring device, and obtaining mixed materials after the low-melting-point chemical fibers and the fiber scraps are mixed uniformly by the stirring device; S4, the mixed material is put into a mold for compression molding, the compression molding includes a pre-pressing stage, a hot-pressing stage and a pressure-maintaining cooling stage, wherein: the pre-pressing stage: 1-2 MPa pressure is applied to the mixed material in the mold; the hot-pressing stage: gradient pressure is applied to the divided regions in the mold, and then balanced pressure is applied to the whole region of the mold, the temperature of the mold is 150 DEG C; the pressure-maintaining cooling stage: the pressure of the mixed material in the mold is maintained, and the mold is cooled; S5, the regenerated felt is obtained by demolding.

[0006] Further, the pre-pressing stage in S4 specifically comprises: before 1-2 MPa pressure is applied to the mold, the surface layer region of the mixed material is scanned by infrared laser; the side of the mold is provided with a window, and high-temperature-resistant quartz glass is embedded in the window; the surface layer region of the mixed material exposed through the window is scanned by the infrared laser through the high-temperature-resistant quartz glass, so that the low-melting-point chemical fiber is pre-melted to form a bonding layer; The wavelength of the infrared laser is 800-1000 nm, the power density of the infrared laser is 50-120 W / cm2, the spot diameter is 1-3 mm, the window region is scanned in a grid path with a spacing of 5-10 mm, and the scanning speed is 10-20 mm / s.

[0007] Further, the divided regions in S4 include a central region covering 45%-50% of the projected area with the geometric center of the mold projection surface as the reference, and a remaining region in the mold as an edge region; The gradient pressure is: 5-7 MPa pressure is applied to the central region, and 2.5-3.5 MPa pressure is applied to the edge region; 5-7 MPa pressure P1 is applied to the central region, and 2.5-3.5 MPa pressure P2 is applied to the edge region, and P1>P2; The balanced pressure is: after 5-7 MPa pressure is applied to the central region and maintained for 3-5 min, the pressure of the edge region is increased to the same 5-7 MPa as the central region and maintained for 3-5 min.

[0008] Further, the pressure-maintaining cooling stage in S4 is that the mold is cooled at a rate of 10-15 DEG C / min to below 60 DEG C under a constant pressure of 5-7 MPa.

[0009] Further, the dehydration in S1 adopts centrifugal dehydration, the rotation speed is 1000-1500 rpm, the dehydration time is 3-10 min, and the moisture content of the fiber scraps after dehydration is 5-8%.

[0010] Further, the content of the low-melting-point chemical fiber in the regenerated felt is 20%-40%, and the balance is fiber scraps.

[0011] Further, the low-melting point chemical fiber in S3 is sprayed with an ethanol solution containing 0.5-1 wt% nano-SiO2 and 0.2-0.5 wt% silane coupling agent on the surface of the low-melting point chemical fiber before mixing with the fiber scraps; The low-melting point chemical fiber is at least one of low-melting point polyester, polypropylene fiber, polyethylene / polypropylene bicomponent fiber or low-melting point modified polylactic acid fiber.

[0012] Further, the melting point of the low-melting point chemical fiber is 120-160℃.

[0013] Further, the waste spinning article in S1 is coarsely crushed to form scraps with a length of 15-50mm, the low-melting point chemical fiber in S2 is cut to a length of 3-8mm, and the stirring device in S3 mixes the low-melting point chemical fiber with the fiber scraps to be uniform after mixing for 5-15min at a speed of 200-500rpm.

[0014] A felt regenerated based on waste spinning articles, comprising a plate body prepared by the above preparation method, wherein the thickness of the plate body is 6mm, 7mm or 8mm, the density of the plate body is 0.8-1.2g / cm3, and the bending strength of the plate body is ≥15MPa.

[0015] The present application has the following positive effects: (1) The present application provides a preparation method of a felt regenerated based on waste spinning articles, which is prepared by crushing and mixing the waste spinning articles and the low-melting point chemical fiber and then press forming in a mold, wherein the press forming is divided into a pre-pressing stage, a hot-pressing stage and a pressure-maintaining and cooling stage. The present application adopts a press forming mode combining gradient pressure and balanced pressure, so that the low-melting point chemical fiber located in the center of the mold flows towards the edge after melting, and then pressure is applied to the whole area in the mold, which better solves the problem that when the conventional hot-pressing directly adopts global balanced pressure, the edge area of the mold has a significantly lower density than the center area due to the fast heat loss and pressure transmission attenuation, so that the prepared felt has a certain strength and hardness, can meet the use requirements of prop display boards, and has good density and uniformity and a smooth surface.

[0016] (2) Before applying 1-2MPa pressure in the pre-pressing stage, the present application adopts infrared laser to irradiate the surface layer area of the mixed material exposed through the window of the mold provided with high-temperature-resistant quartz glass, the low-melting point chemical fiber located in the surface layer is pre-melted to form a continuous adhesive layer on the surface of the mixed material in the mold, and a fixed layer is formed on the surface of the regenerated felt after the mixed material is press formed, which can prevent the edge of the mixed felt from cracking after forming. At the same time, the properties of different materials can cause thermal stress of the materials and cracking when globally hot-pressed, and the pre-melting by infrared laser and the mode combining gradient pressure and balanced pressure can avoid the problem of thermal stress of the materials caused by global hot-pressing.

[0017] (3) The application adopts the mixed pressing of waste spun articles and low-melting chemical fibers, takes the waste spun articles as the main raw material, greatly reduces the production cost of the felt, realizes 100% utilization of waste textiles, avoids the use of thermoplastic adhesives, and does not produce formaldehyde pollution in the production process and subsequent use.

[0018] (4) The felt regenerated based on waste spun articles has excellent sound absorption and sound insulation performance, has low production cost compared with ordinary decorative panels, is pollution-free and more environmentally friendly and energy-saving, and can be cut into different sizes to make prop display boards, and is suitable for various exhibition, commercial display and other scenes. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to make the content of the application more easily and clearly understood, the application will be further described in detail below according to specific embodiments and in conjunction with the drawings, in which Figure 1 It is a step flow diagram of the application. Figure 2 It is a structure diagram of the mold in the S4 step of the application.

[0020] In the figure, the mold is 1, the window is 2, and the high-temperature-resistant quartz glass is 3. DETAILED DESCRIPTION

[0021] The application has waste spun articles and low-melting chemical fibers; comprising the following steps: S1, preparing waste spun articles and low-melting chemical fibers; removing non-fabric impurities from the waste spun articles containing natural fibers and / or synthetic fibers, coarsely crushing the waste spun articles to form fragments, and obtaining fiber fragments after fine opening and dehydration of the fragments; S2, cutting the low-melting chemical fibers; S3, stirring the low-melting chemical fibers and the fiber fragments in a stirring device, mixing the low-melting chemical fibers and the fiber fragments to be uniform in the stirring device to obtain a mixed material; S4, placing the mixed material into a mold for pressing and forming, the pressing and forming includes a pre-pressing stage, a hot-pressing stage and a pressure-maintaining and cooling stage, wherein: in the pre-pressing stage, a pressure of 1-2 MPa is applied to the mixed material in the mold; in the hot-pressing stage, the mold is first divided into regions, then gradient pressure is applied to the regions, and then balanced pressure is applied to the whole region of the mold, and the temperature of the mold is 150 DEG C; in the pressure-maintaining and cooling stage, the pressure of the mixed material in the mold is maintained, and the mold is cooled; S5, demolding to obtain a regenerated felt.

[0022] The application provides a preparation method of a felt based on waste spinning articles, wherein the waste spinning articles in the application contain natural fibers and synthetic fibers, the synthetic fibers are used as raw materials of the regenerated felt in the application, and the low-melting synthetic fiber is a kind of synthetic fiber with a low melting point, which is used for adhesion and forming in the processing of the regenerated felt in the application and cannot be used as the main structure of the textile and for hot melt bonding.

[0023] The waste spinning articles and the low-melting synthetic fiber are pretreated first, then mixed, and then formed into the regenerated felt through hot pressing; in the process of hot pressing, the low-melting synthetic fiber is heated and melted to bond the fiber scraps of the waste spinning articles together; the preparation method avoids the use of thermoplastic adhesives and does not cause formaldehyde pollution in the production process and subsequent use; after being melted, the low-melting synthetic fiber serves as an adhesive to form a partially open bonding network between the fibers, and the small pores formed between the low-melting synthetic fiber and the fiber scraps; when the sound wave propagates in the pores, it rubs against the surface of the fiber to generate viscous loss, and the compression and expansion of air in the pores cause heat conduction loss, so that the sound energy is converted into heat energy and dissipated; the felt based on waste spinning articles has excellent sound absorption and sound insulation performance, has a low production cost compared with ordinary decorative panels, and is pollution-free and more environmentally friendly and energy-saving; the felt based on waste spinning articles can be cut into different sizes to make prop display boards, and is suitable for various exhibition, commercial display and other scenes.

[0024] The pre-pressing stage in S4 is specifically that the surface layer region of the mixed material is scanned by an infrared laser before 1-2 MPa pressure is applied to the mold; see Figure 2 The side of the mold is provided with a window, the window is embedded with high-temperature-resistant quartz glass, and the four sides of the mold can also be provided with windows embedded with high-temperature-resistant quartz glass; the surface layer region of the mixed material exposed through the window is scanned by the infrared laser through the high-temperature-resistant quartz glass to make the low-melting synthetic fiber pre-melted to form a bonding layer; the light transmittance of the high-temperature-resistant quartz glass is > 90%, which can allow the infrared laser to scan the mixed material to the maximum extent; The wavelength of the infrared laser is 800-1000 nm, the power density of the infrared laser is 50-120 W / cm2, the spot diameter is 1-3 mm, the window area is scanned in a grid path with a spacing of 5-10 mm, and the scanning speed is 10-20 mm / s; before applying pressure to the mold, the low-melting-point chemical fiber in the surface layer is pre-melted to form a continuous bonding layer by scanning with the infrared laser; the continuous bonding layer improves the surface density of the mixed material in the mold, preventing delamination of the surface layer during subsequent hot pressing; meanwhile, after the low-melting-point chemical fiber in the surface layer is pre-melted to form a continuous bonding layer, a pressure of 1-2 MPa is applied to the mixed material in the mold during the pre-pressing stage in S4, the 1-2 MPa pressure is applied to the entire area of the mold, the 1-2 MPa pressure eliminates the pores between the mixed materials in the mold, and the low-melting-point chemical fiber that has been pre-melted to form a continuous bonding layer on the surface of the mixed material in the mold spreads on the surface of the mixed material, forming a fixed layer on the surface of the regenerated felt after the mixed material is pressed, preventing material thermal stress caused by global hot pressing.

[0025] The divided areas in S4 include a central area covering 45%-50% of the projected area with the geometric center of the mold projection surface as the reference, and a remaining area in the mold as the edge area; the low-melting-point chemical fiber in the mixed material in the mold forms a low-melting-point chemical fiber melt after being heated; The gradient pressure is 5-7 MPa for the central area and 2.5-3.5 MPa for the edge area; the pressure P1 applied to the central area is 5-7 MPa, the pressure P2 applied to the edge area is 2.5-3.5 MPa, and P1>P2; the low-melting-point chemical fiber melt in the central area of the mold flows to the edge area after being pressed, the low-melting-point chemical fiber melt flowing to the edge area adheres to the edge of the mold, and the low-melting-point chemical fiber melt in the edge area flows and fills the gaps between the chemical fiber scraps, preventing the mixed material in the edge area from forming a low density after being pressed; The equalizing pressure is to increase the pressure in the edge area to 5-7 MPa, the same as the central area, and maintain it for 3-5 min after applying 5-7 MPa pressure to the central area for 3-5 min; the low-melting-point chemical fiber melt in the central area fully adheres to the fiber scraps, and the low-melting-point chemical fiber melt flowing from the central area to the edge area and the low-melting-point chemical fiber melt originally in the edge area fully adhere to the fiber scraps in the edge area after the pressure in the edge area is increased to 5-7 MPa, the same as the central area, and maintained for 3-5 min; the low-melting-point chemical fiber melt in the central area and the edge area fully adheres to the fiber scraps under the same pressure, ensuring that the mixed material in the central area and the edge area has consistent density after forming the regenerated felt.

[0026] The pressure maintaining and cooling stage in S4 is to maintain a constant pressure of 5-7 MPa, and the mold is cooled at a rate of 10-15 ℃ / min to below 60 ℃; through the process of cooling at a certain rate, the low-melting point chemical fiber melt is gradually cooled and shaped.

[0027] The dehydration in S1 is centrifugal dehydration, and the centrifugal dehydration is adopted, the rotating speed during centrifugal dehydration is 1000-1500 rpm, and the centrifugal dehydration time is 3-10 min; the water content of the fiber scraps during centrifugal dehydration is controlled to be 5-8%, and the principle of controlling the water content to be 5-8% is that: when the water content of the fiber scraps is too low, electrostatic flying will be caused during subsequent mixing with the low-melting point chemical fiber; when the water content of the fiber scraps is too high, water will be removed in the form of steam during hot pressing, which affects the bending strength of the regenerated felt.

[0028] Before the low-melting point chemical fiber is mixed with the fiber scraps in S3, an ethanol solution containing 0.5-1 wt% nano-SiO2 and 0.2-0.5 wt% silane coupling agent is sprayed on the surface of the low-melting point chemical fiber; the silane coupling agent is difficult to dissolve in water but easy to dissolve in organic solvents such as ethanol, and ethanol can effectively dissolve the silane coupling agent; the weak polarity of ethanol can maintain the uniform suspension of nanoparticles, that is, nano-SiO2 can be suspended in the ethanol solution without agglomeration and sinking to the bottom; the nano-particles improve the melt viscosity, and the coupling agent promotes chemical bonding with natural fibers; at the same time, since ethanol is volatile, when the ethanol solution containing nano-SiO2 and silane coupling agent is sprayed on the surface of the low-melting point chemical fiber, ethanol quickly volatilizes, and nano-SiO2 and silane coupling agent are attached to the surface of the low-melting point chemical fiber; the interfacial bonding strength, overall mechanical properties and dimensional stability of the felt obtained by mixing and compression molding of the waste textile and the low-melting point chemical fiber are improved.

[0029] The ethanol solution containing 0.5-1 wt% nano-SiO2 and 0.2-0.5 wt% silane coupling agent is a dispersion liquid specially used for surface modification or functional treatment of materials. Its core function is to construct a composite coating layer with nano-enhancing effect and interface optimization function on the surface of the substrate through a simple coating or dipping process, and in the present application, the function is to form a composite coating layer on the surface of the low-melting point chemical fiber, which can improve the bonding force of the low-melting point chemical fiber and the fiber scraps during compression molding; at the same time, a strong connection between the waste textile fiber and the low-melting point chemical fiber is established through the silane coupling agent.

[0030] The low-melting point chemical fiber is at least one of low-melting point polyester, polypropylene fiber, polyethylene / polypropylene bicomponent fiber or polylactic acid (PLA) low-melting point modified fiber; in the present application, polyethylene / polypropylene bicomponent fiber is preferred, after the polyethylene / polypropylene bicomponent fiber is heated, the skin layer low-temperature melts to play a role in bonding the fiber scraps, and the core layer retains the mechanical strength, avoiding the addition of additional adhesives.

[0031] The low-melting point chemical fiber has a melting point of 120-160℃, and the preferred polyethylene / polypropylene bicomponent fiber in the present application adopts a skin-core structure, with low-melting point polyethylene as the skin layer and high-melting point polypropylene as the core layer. In actual processing, the melting point of the polyethylene skin layer is 130-160℃, and under this melting point, the temperature of the polyethylene / polypropylene bicomponent fiber and the fiber scraps during compression molding needs to reach 130-160℃.

[0032] The waste textile scraps in S1 are coarsely crushed into pieces with a length of 15-50mm, the low-melting point chemical fiber in S2 is cut into a length of 3-8mm, and the mixing device in S3 mixes the low-melting point chemical fiber and the fiber scraps uniformly for 5-15min at a speed of 200-500rpm.

[0033] When the waste textile scraps are coarsely crushed into pieces with a length of 15-50mm, the longer pieces are the main source of the load-bearing capacity of the felt, and the pieces interweave to form a skeleton structure. When the length of the pieces is <15mm, the mechanical strength of the felt formed by compression with the low-melting point chemical fiber is greatly weakened; when the length of the pieces is >50mm, it is difficult to uniformly lay the pieces, and entanglement, arching or uneven distribution may occur during laying and hot pressing, resulting in uneven felt density, warping or delamination.

[0034] When the low-melting point chemical fiber is cut into a length of 3-8mm, the shorter fibers are more easily uniformly dispersed in the waste textile scrap pieces, ensuring the formation of an effective network of bonding points in the entire felt, while providing sufficient bonding area while avoiding excessive melting or uneven bonding in local areas due to excessively long fibers.

[0035] A felt regenerated based on waste textile scraps, comprising a plate body prepared by the above preparation method, wherein the thickness of the plate body is 6mm, 7mm or 8mm, the density of the plate body is 0.8-1.2g / cm3, and the bending strength of the plate body is ≥15MPa.

[0036] Application of a felt regenerated based on waste textile scraps, for making building or decorative felt, display materials, soundproofing materials or packaging materials, and the felt is processed according to design requirements.

[0037] The present application will be further described in detail by specific examples, but it should be understood that these examples are only used for more detailed description and should not be understood as limiting the present application in any form The fiber scraps of the application are obtained by the following way: waste textile articles are recycled, non-fabric foreign matter is removed, that is, unusable parts such as metal, buttons or prints are cut off, the cut waste textiles are classified by color and packed; the waste textile articles are cut into pieces by a double-shaft shearing crusher to avoid excessive damage to the fibers, which is rough crushing; the pieces are then broken down into fiber scraps by a spike roller opener, which is fine opening, and after fine opening, the fiber scraps are obtained by dehydration treatment by a centrifugal dehydration device; the recycled waste textiles are divided and cut, and different colored raw materials are subdivided, in order to better apply to products and control the performance of the final products. If the application does not have high requirements on appearance and color, these operations can be omitted.

[0038] The synthetic fiber in the obtained fiber scraps accounts for ≥60%, and the specific surface area of the fibers after piece opening is increased, thereby enhancing the bonding force during subsequent mixing and pressing of single fibers and low-melting chemical fibers.

[0039] (Example 1) A preparation method of a felt based on waste textile articles, comprising the following steps: S1, removing non-fabric foreign matter from waste textile articles containing natural fibers and / or synthetic fibers, and forming 30mm long pieces by rough crushing, and then obtaining fiber scraps by fine opening and dehydration of the pieces; S2, the low-melting chemical fiber is a polyethylene / polypropylene bicomponent fiber, and the low-melting chemical fiber is cut to a length of 5mm; S3, the low-melting chemical fiber and the fiber scraps are put into a stirring device in a proportion of 60% fiber scraps and 40% low-melting chemical fiber, and stirred for 5min at a speed of 500rpm to obtain a mixture; S4, the mixture is put into a mold for pressing and molding, the pressing and molding includes a pre-pressing stage, a hot-pressing stage and a pressure-maintaining and cooling stage, the side of the mold is provided with a window, and high-temperature-resistant quartz glass is embedded in the window; S4.1, pre-pressing stage: the infrared laser has a wavelength of 808nm, a power density of 120W / cm², and a spot diameter of 3mm, scans the window area at a grid path with a spacing of 5mm, and the scanning speed is 10mm / s; a pressure of 1MPa is applied to the mixture in the mold; S4.2, hot pressing stage: 5 MPa pressure is applied to the mixed material located in the center area of the mold, 2.5 MPa pressure is applied to the mixed material located in the edge area of the mold; after 5 min of applying 5 MPa pressure to the mixed material located in the center area of the mold, the 2.5 MPa pressure applied to the mixed material located in the edge area of the mold is increased to the same 5 MPa as the center area and maintained for 5 min, and the total duration of the applied pressure in the hot pressing stage is 10 min; the temperature of the mold during the hot pressing stage is constant at 150°C; S4.3, pressure maintaining and cooling stage: a constant 5 MPa pressure is maintained in the entire mold internal area, and the mold is cooled to below 60°C at a rate of 15°C / min by forced air cooling; S5, demolding to obtain regenerated felt with a density of 0.8 g / cm³ and a thickness of 8 mm.

[0040] (Example 2) A method for preparing regenerated felt based on waste spun articles, comprising the following steps: S1, removing non-fabric impurities from waste spun articles containing natural fibers and / or synthetic fibers, and forming 30 mm long fragments by rough crushing, and then obtaining fiber fragments by fine opening and dehydration; S2, the low-melting chemical fiber is a polyethylene / polypropylene bicomponent fiber, and the low-melting chemical fiber is cut to a length of 5 mm; S3, the low-melting chemical fiber and the fiber fragments are mixed in a stirring device at a ratio of 70% fiber fragments and 30% low-melting chemical fiber, and the stirring device is mixed at a speed of 300 rpm for 10 min to obtain a mixed material; S4, the mixed material is placed in a mold for compression molding, and the compression molding includes a pre-pressing stage, a hot pressing stage, and a pressure maintaining and cooling stage, and the side of the mold is provided with a window, and the window is embedded with high-temperature-resistant quartz glass; S4.1, pre-pressing stage: the infrared laser has a wavelength of 808 nm, a power density of 90 W / cm², and a spot diameter of 2 mm, and scans the window area at a grid path with a spacing of 7 mm at a scanning speed of 15 mm / s; 1.5 MPa pressure is applied to the mixed material in the mold; S4.2, hot pressing stage: 6 MPa pressure is applied to the mixed material located in the center area of the mold, and 3 MPa pressure is applied to the mixed material located in the edge area of the mold; after 4 min of applying 6 MPa pressure to the mixed material located in the center area of the mold, the 4 MPa pressure applied to the mixed material located in the edge area of the mold is increased to the same 6 MPa as the center area and maintained for 4 min, and the total duration of the applied pressure in the hot pressing stage is 8 min; the temperature of the mold during the hot pressing stage is constant at 150°C; S4.3, pressure maintaining and cooling stage: a constant pressure of 7 MPa is maintained in the whole mold, and the mold is cooled to below 60℃ at a rate of 10℃ / min by forced air cooling; S5, the regenerated felt with a density of 1.2 g / cm³ and a thickness of 6 mm is obtained.

[0041] (Example 3) A method for preparing a regenerated felt based on waste spun articles, comprising the following steps: S1, removing non-fabric impurities from the waste spun articles containing natural fibers and / or synthetic fibers, and forming 30 mm long fragments by rough crushing, and then obtaining fiber fragments by fine opening and dehydration; S2, the low-melting chemical fiber is a polyethylene / polypropylene bicomponent fiber, and the low-melting chemical fiber is cut to a length of 5 mm; S3, the low-melting chemical fiber and the fiber fragments are mixed in a stirring device at a ratio of 80% fiber fragments and 20% low-melting chemical fiber, and the stirring device is mixed at a speed of 200 rpm for 15 min to obtain a mixed material; S4, the mixed material is placed into a mold for compression molding, and the compression molding includes a pre-pressing stage, a hot-pressing stage, and a pressure maintaining and cooling stage, and the side of the mold is provided with a window, and the window is embedded with high-temperature-resistant quartz glass; S4.1, pre-pressing stage: the infrared laser has a wavelength of 808 nm, a power density of 90 W / cm², and a spot diameter of 2 mm, and scans the window area at a grid path with a spacing of 7 mm at a scanning speed of 15 mm / s; a pressure of 2 MPa is applied to the mixed material in the mold; S4.2, hot-pressing stage: a pressure of 7 MPa is applied to the mixed material in the center area of the mold, and a pressure of 3.5 MPa is applied to the mixed material in the edge area of the mold; after the pressure of 7 MPa is applied to the mixed material in the center area of the mold for 3 min, the pressure of 3.5 MPa applied to the mixed material in the edge area of the mold is increased to the same pressure of 7 MPa and maintained for 3 min, and the total time of the applied pressure in the hot-pressing stage is 6 min; the temperature of the mold is constant at 150℃ during the hot-pressing stage; S4.3, pressure maintaining and cooling stage: a constant pressure of 7 MPa is maintained in the whole mold, and the mold is cooled to below 60℃ at a rate of 10℃ / min by forced air cooling; S5, the regenerated felt with a density of 1.2 g / cm³ and a thickness of 6 mm is obtained.

[0042] The above-described specific embodiments further illustrate the purpose, technical solutions and beneficial effects of the present application, and it should be understood that the above-described specific embodiments are merely examples of the present application and are not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for producing a felt based on the regeneration of waste spun material, characterized in that, The method comprises the following steps: S1, preparing waste spun articles and low-melting chemical fibers; removing non-fabric impurities from the waste spun articles containing natural fibers and / or synthetic fibers, coarsely crushing the waste spun articles to form fragments, and then finely opening and dehydrating the fragments to obtain fiber fragments; S2, cutting the low-melting chemical fibers; S3, stirring the low-melting chemical fibers and the fiber fragments in a stirring device to mix the low-melting chemical fibers and the fiber fragments uniformly to obtain a mixed material; S4, pressing and forming the mixed material in a mold, wherein the pressing and forming comprises a pre-pressing stage, a hot-pressing stage, and a pressure-maintaining and cooling stage; in the pre-pressing stage, a pressure of 1-2 MPa is applied to the mixed material in the mold; in the hot-pressing stage, a gradient pressure is applied to the divided regions in the mold, and then an equalizing pressure is applied to the whole region in the mold, and the temperature of the mold is 150°C; in the pressure-maintaining and cooling stage, the pressure on the mixed material in the mold is maintained, and the mold is cooled; S5, demolding to obtain a regenerated felt.

2. A method of making a felt based on the regeneration of waste textile articles according to claim 1, characterized in that: In the pre-pressing stage of S4, before the pressure of 1-2 MPa is applied to the mold, the surface layer region of the mixed material is scanned by an infrared laser; the side of the mold is provided with a window, and high-temperature-resistant quartz glass is embedded in the window; the surface layer region of the mixed material exposed through the window is scanned by the infrared laser through the high-temperature-resistant quartz glass, so that the low-melting chemical fibers are pre-melted to form a bonding layer; The wavelength of the infrared laser is 800-1000 nm, the power density of the infrared laser is 50-120 W / cm², the spot diameter is 1-3 mm, the window region is scanned at a grid path with a spacing of 5-10 mm, and the scanning speed is 10-20 mm / s.

3. A method of making a felt based on regeneration of waste textile articles according to claim 1, characterized by: In the divided region of S4, the region covering 45%-50% of the projection area with the geometric center of the mold projection surface as the reference is the center region, and the remaining region in the mold is the edge region; The gradient pressure is that a pressure of 5-7 MPa is applied to the center region, and a pressure of 2.5-3.5 MPa is applied to the edge region; the pressure P1 applied to the center region is 5-7 MPa, the pressure P2 applied to the edge region is 2.5-3.5 MPa, and P1>P2; The equalizing pressure is that after the pressure of 5-7 MPa is applied to the center region and maintained for 3-5 min, the pressure of the edge region is increased to the same 5-7 MPa as the center region and maintained for 3-5 min.

4. A method of making a felt based on regeneration of waste textile articles according to claim 1, characterized in that: In the pressure-maintaining and cooling stage of S4, the mold is cooled at a rate of 10-15°C / min to below 60°C under a constant pressure of 5-7 MPa.

5. A method of making a felt based on regeneration of waste textile articles according to claim 1, characterized in that: In S1, centrifugal dehydration is used, the rotating speed is 1000-1500 rpm, the dehydration time is 3-10 min, and the water content of the fiber fragments after dehydration is 5-8%.

6. A method of making a felt based on regeneration of waste textile articles according to claim 1, characterized in that: The content of the low-melting chemical fibers in the regenerated felt is 20%-40%, and the balance is the fiber fragments.

7. A method of making a felt based on regeneration of waste textile articles according to claim 1, characterized in that: Before the low-melting chemical fibers are mixed with the fiber fragments in S3, an ethanol solution containing 0.5-1 wt% nano-SiO2 and 0.2-0.5 wt% silane coupling agent is sprayed on the surface of the low-melting chemical fibers; The low-melting chemical fiber is at least one of low-melting polyester, polypropylene fiber, polyethylene / polypropylene bicomponent fiber or low-melting modified polylactic acid fiber.

8. A method of making a felt based on regeneration of waste textile articles according to claim 1, characterized in that: The low-melting chemical fiber has a melting point of 120-160 DEG C.

9. A method of making a felt based on regeneration of waste textile articles according to claim 1, characterized in that: The waste spinning article in S1 is coarsely crushed to form fragments with a length of 15-50 mm, the low-melting chemical fiber in S2 is cut to a length of 3-8 mm, and the stirring device in S3 is mixed at a speed of 200-500 rpm for 5-15 min to mix the low-melting chemical fiber and the fiber fragments uniformly.

10. A felt based on the regeneration of waste spun material, characterized by: The plate body is prepared by the method according to any one of claims 1-9, and has a thickness of 6 mm, 7 mm or 8 mm, a density of 0.8-1.2 g / cm3 and a bending strength of ≥15 MPa.

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