Method for preparing wool felt from waste wool fibers and other short fibers

Abstract

The invention relates to the field of textile materials, and particularly discloses a method for preparing wool felt by mixing waste wool fibers with other short fibers. The invention discloses a method for preparing wool felt by mixing waste wool fibers and other short fibers. The method comprises the following steps: mixing the waste wool fibers and the short fibers, and then mixing with a low-melting-point thermoplastic high polymer adhesive to obtain a mixture; placing the mixture in a mold for hot press molding to obtain felt blanks, heating a low-melting-point thermoplastic high polymer adhesive to a molten state, spraying the low-melting-point thermoplastic high polymer adhesive on the surfaces of the felt blanks, stacking and laminating a plurality of felt blanks after spraying, carrying out primary curing treatment, and carrying out secondary curing treatment after the primary curing treatment is completed to obtain the felt. Local heating and shaping are carried out on the overlapped positions of the multiple layers of felt blanks; and performing needling reinforcement on the partially heated and shaped felt blank by using a needling machine to obtain the wool felt. The method for preparing the wool felt by mixing the waste wool fibers and other short fibers has the advantage that the mechanical performance of the wool felt is improved.

Description

Technical Field

[0001] The present application relates to the field of textile materials, and more specifically, to a method for preparing wool felt by mixing waste wool fibers with other short fibers. Background Art

[0002] Wool felt is widely used due to its excellent properties such as warmth retention, moisture absorption and breathability. However, the preparation of traditional wool felt mainly depends on the shrinkage performance of wool fiber, and the presence of scale layer on the surface of wool fiber is the basis of its shrinkage performance. In the leather and fur industry, a large amount of waste wool fiber is generated, but only a small amount is used for keratin extraction, and most of it is landfilled or incinerated, resulting in resource waste and environmental pollution.

[0003] At present, some studies have attempted to process waste wool fibers into felt products. However, since waste wool fibers are usually treated by liming, the surface scale layer is severely damaged, resulting in a significant decrease in the felt shrinkage performance, making it difficult to form wool felt with good strength and elasticity. In addition, the traditional glue spraying process has the problem of difficult control of the glue amount in the preparation of wool felt. Too much glue spraying will make the wool felt stiff and lose elasticity, while too little glue spraying will result in poor felt strength and easy hair loss.

[0004] Based on this, a method has been developed to combine waste wool fibers with other short fibers and enhance the fiber bonding strength through low-melting point thermoplastic polymer adhesives and fiber welding technology. This can improve the felting properties of waste wool fibers and significantly enhance the strength and elasticity of the product, while reducing resource waste and improving environmental problems. Summary of the invention

[0005] In order to improve the mechanical properties of wool felt and solve the problem of difficult to control the amount of adhesive used in traditional processes, the present application provides a method for preparing wool felt by mixing waste wool fibers with other short fibers.

[0006] The present application provides a method for preparing wool felt by mixing waste wool fibers with other short fibers, which adopts the following technical solution: A method for preparing wool felt by mixing waste wool fibers with other short fibers comprises the following steps: Treating waste wool fibers in a weak acid solution for 5-10 minutes, mixing 6-9 parts by weight of the waste wool fibers with 1-4 parts of staple fibers to obtain 10 parts by weight of mixed fibers, mixing the mixed fibers with a low-melting-point thermoplastic polymer binder at 50-60° C., wherein the amount of the low-melting-point thermoplastic polymer binder added is 4-6% of the mass of the mixed fibers, to obtain a mixture; The mixed material is placed in a mold for hot pressing to obtain a felt blank with a single layer thickness of 1-1.3 mm, a low melting point thermoplastic polymer adhesive is heated to a molten state and sprayed on the surface of the felt blank, and after spraying, multiple felt blanks are stacked and bonded, and then subjected to a preliminary curing treatment, the preliminary curing temperature is 80-100° C., and the time is 15-30 minutes. After the preliminary curing treatment is completed, local heating and shaping are performed at the overlapping position of the multi-layer felt blanks, and the heating temperature is 100-110° C.; A needle punching machine is used to perform needle punching reinforcement on the felt blank after local heating and shaping. After the needle punching is completed, the surface of the felt blank is trimmed to obtain wool felt.

[0007] By adopting the above technical solution, the waste wool fibers are treated in a weak acid solution, which can remove impurities and partially damaged cuticles that may exist on the fiber surface, making the fiber surface cleaner and more activated, which is conducive to the subsequent combination with low-melting-point thermoplastic polymer adhesives and other short fibers. The utilization of a larger amount of waste wool fibers not only helps to solve the problem of recycling waste resources, but also, under the mixing ratio of the present application, can make the wool felt maintain the characteristics of wool while using the characteristics of other short fibers to compensate for the performance degradation of the waste wool fibers caused by the damage to the surface scale layer, thereby optimizing the comprehensive performance of the wool felt. The low melting point thermoplastic polymer adhesive is mixed with the mixed fiber at 50-60℃, and the addition amount is 4-6% of the mixed fiber mass. This temperature range can ensure that the adhesive can well infiltrate the fiber without causing excessive damage to the fiber due to high temperature. At the same time, it avoids the problem of difficult to control the amount of adhesive used in traditional processes, and prevents the wool felt from becoming stiff and losing elasticity due to excessive glue or the felt body from having poor strength and easy hair loss due to too little glue. The wool felt can form a stable and appropriate fiber-to-fiber connection during the molding process, which helps to improve the mechanical properties of the wool felt, such as strength and elasticity. The mixed material is first hot-pressed to obtain a felt blank, and then the blank is subsequently processed. The hot-pressing molding process allows the mixed fiber to be initially tightly combined, which is conducive to further fusion and strengthening between each layer of the blank and between the fibers, thereby improving the overall density and strength of the wool felt. The low melting point thermoplastic polymer adhesive is heated to a molten state and sprayed on the surface of the felt blank. After multiple layers are stacked and bonded, they are initially cured so that each layer of the felt blank is connected by the adhesive. Local heating at 100-110°C is performed at the overlapping position of the multi-layer felt blank to further strengthen the strength of the interlayer bonding part, making the multi-layer structure more stable and reducing the possibility of interlayer separation. At the same time, local heating also avoids the performance degradation caused by overheating the overall felt blank, ensuring the quality and performance uniformity of the wool felt. The felt blank is needled and reinforced using a needle punching machine. The needle punching process causes the fibers to interweave and entangle with each other, further enhancing the friction and cohesion between the fibers, improving the compactness and strength of the wool felt, and improving its dimensional stability, so that it is not easy to deform or loosen during use. In summary, the preparation of wool felt by this method can effectively improve the mechanical properties of the wool felt, solve the problem of difficult to control the amount of adhesive used in traditional processes, and at the same time make full use of waste wool fibers to achieve resource recycling and environmentally friendly production, and prepare high-quality and high-performance wool felt products with good economic and environmental benefits, which can meet the market demand for high-quality wool felt products.

[0008] Optionally, the wool felt comprises, by mass percentage, 40%-90% of waste wool fibers, 10%-60% of short fibers, and 10%-20% of a low-melting-point thermoplastic polymer adhesive.

[0009] By adopting the above technical solution, the content of waste wool fibers can be controlled at 40%-90%, which means that a large amount of waste wool fibers that might have been landfilled or incinerated have been effectively utilized as resources, reducing the pressure on the environment, complying with the environmental protection concept of sustainable development, while reducing the cost of raw materials and improving the economy of wool felt production. Short fibers can be filled between waste wool fibers in the mixed system to optimize the stacking structure of the fibers, making the inside of the wool felt more dense and uniform, reducing pores and defects, thereby improving the overall strength and stability of the wool felt, preventing deformation and breakage during use, and extending the service life and reliability of the product. Low-melting-point thermoplastic polymer adhesives with a content of 10%-20% can not only ensure a good bonding effect, but also avoid problems such as excessive hardness, loss of elasticity and flexibility of the wool felt due to excessive adhesive, or the inability to achieve effective fiber-to-fiber connection due to too little adhesive, thereby achieving a good balance between process operability and product performance.

[0010] Optionally, the components of the low melting point thermoplastic polymer adhesive include, by mass percentage, 60% resin material, 30% rosin-based tackifier, 8% dioctyl phthalate, 0.5% antioxidant and 1.5% polyethylene glycol.

[0011] Optionally, the preparation method of the low melting point thermoplastic polymer adhesive is: The resin material is heated to a molten state, a rosin-based tackifier is added to the molten resin material, and the mixture is continuously stirred and mixed; a plasticizer and polyethylene glycol are then added to the molten resin material and mixed evenly, and the melt is extruded through a mold and cooled to obtain a low-melting-point thermoplastic polymer adhesive.

[0012] By adopting the above technical solution, the resin material as the main component has certain viscosity and melting properties. It can wrap and bond the waste wool fibers and short fibers after heating and melting, providing a key physical connection for the bonding between fibers in the wool felt. It is an important basis for ensuring the overall structural stability and strength of the wool felt. The addition of rosin-based tackifiers can effectively improve the viscosity of the adhesive. It can synergize with the resin material to form a stronger adsorption and bonding effect on the fiber surface, further enhance the connection strength between the fibers, and make the wool felt less prone to problems such as loose fibers and hair loss during use. Rosin-based substances have certain flexibility and moisturizing properties. After being incorporated into the adhesive, they can improve the overall flexibility of the adhesive, avoid the wool felt being too hard and having a poor feel, and make the wool felt have good strength while maintaining appropriate softness and elasticity. As a plasticizer, dioctyl phthalate can be inserted between the molecular chains of the resin material, weaken the intermolecular forces, increase the mobility and flexibility of the molecular chains, and make the adhesive have better fluidity in the molten state, so that it can evenly penetrate between the fibers, ensuring that each fiber can be fully wrapped and bonded. It helps to reduce the hardness and brittleness of the adhesive, so that the wool felt will not become stiff and brittle due to the adhesive after molding, and improves the processability of the wool felt. The presence of antioxidants can capture and inhibit the free radical reaction in the adhesive, delay its oxidation process, and prevent the degradation of the adhesive performance caused by oxidation, such as discoloration, brittleness, and loss of viscosity. Problems, thereby ensuring that the performance of the wool felt remains stable for a long time and extending the service life and shelf life of the wool felt product. Polyethylene glycol can adjust the viscosity and rheology of the adhesive, which not only helps to better mix with other components in the early stage of preparation, but also shows good wettability and adhesion when combined with fibers later, ensuring that the bonding between fibers is firm and uniform.

[0013] Optionally, the resin material is selected from one of ethylene-vinyl acetate copolymer, polyamide resin, polyethylene or thermoplastic polyurethane.

[0014] By adopting the above technical scheme, ethylene-vinyl acetate copolymer (EVA) is selected as the resin material, which can give the wool felt good flexibility, elasticity and bonding properties, and its suitable melting point and processing properties can avoid thermal damage to the fiber; polyamide resin can enhance the strength, wear resistance and thermochemical stability of the wool felt, and has good affinity with the fiber; polyethylene has cost advantages and chemical stability, good processing performance, and may also have moisture-proof barrier properties; thermoplastic polyurethane can make the wool felt have excellent elasticity, wear resistance and low temperature resistance, and has good compatibility and good adhesion with a variety of fibers.

[0015] Optionally, the staple fibers include one or more of natural fibers, synthetic fibers and bio-based fibers.

[0016] Optionally, the conditions for the needling reinforcement are needling density: 1000-3000 needles / m2, needling depth: 1-2mm, needling speed: 1200-2500 needles / minute, needling angle: 50-60 degrees, needling machine pressure: 1.5-3MPa.

[0017] By adopting the above technical solution, the needle density is 1000-3000 needles / m 2 It can strengthen fiber entanglement, improve uniformity, enhance tensile and tear strength, and ensure consistent performance and appearance quality; acupuncture depth of 1-2mm can achieve moderate entanglement and structural stability, adjust porosity and optimize air permeability, and maintain flexibility and elasticity; acupuncture speed of 1200-2500 needles / minute can balance production efficiency and quality, and ensure uniform and sufficient acupuncture; acupuncture angle of 50-60 degrees is conducive to fiber directional arrangement and force optimization, and improves surface quality and feel; acupuncture machine pressure of 1.5-3MPa can strongly entangle and improve performance, while controlling fiber damage to ensure the strength, compactness, dimensional stability and comprehensive performance of wool felt.

[0018] Optionally, the waste wool fibers have a length of 2-5 cm and a diameter of 20-40 μm, and the short fibers have a length of 1-3 cm and a diameter of 20-30 μm.

[0019] By adopting the above technical solution, when mixed with a low-melting-point thermoplastic polymer adhesive and short fibers, the longer waste wool fibers can form a more continuous and stable fiber network structure, providing a certain structural strength foundation for the wool felt, so that when subjected to external forces such as stretching, the fibers are not easy to slip and separate, thereby improving the overall tensile strength and toughness of the wool felt. The length range of the short fibers cooperates with the waste wool fibers, and the shorter length enables them to fill in the gaps between the waste wool fibers, further optimizing the fiber stacking structure, increasing the contact points and friction between the fibers, making the internal structure of the wool felt more dense and uniform, and improving the compactness and integrity of the wool felt.

[0020] In summary, this application has the following beneficial effects: 1. The present application prepares waste wool fibers by treating them with weak acid, mixing them with staple fibers in a specific proportion, adding an appropriate amount of low-melting-point thermoplastic polymer adhesive at a suitable temperature, and performing steps such as hot pressing, blank stacking and local heating, needle punching reinforcement and surface trimming. It not only removes impurities and activates the fiber surface to facilitate combining with other materials, but also solves the problem of difficult control of adhesive dosage, avoids affecting the elasticity and strength of wool felt due to adhesive quantity problems, strengthens interlayer bonding and fiber entanglement, improves the overall density, compactness, strength and dimensional stability, makes full use of waste resources, realizes environmentally friendly production, and prepares high-quality wool felt products with excellent comprehensive performance, good economic and environmental benefits to meet market demand.

[0021] 2. Compared with the traditional wool felt technology, the wool felt based on waste wool fiber produced by the process of this application has a higher fiber content of waste wool, which can reach up to 90%.

[0022] 3. The method of the present application uses less adhesive than wool felt products obtained by other melt-bonding techniques, and the modified low-temperature melting adhesive allows the wool felt products to maintain their own softness and elasticity. DETAILED DESCRIPTION

[0023] The present application is further described in detail below in conjunction with the examples. It is particularly noted that if no specific conditions are specified in the following examples, the experiments are carried out according to conventional conditions or the conditions recommended by the manufacturer. Unless otherwise specified, the raw materials used in the following examples can be obtained from common commercial sources.

[0024] Preparation Example of Low Melting Point Thermoplastic Polymer Adhesive Preparation Example 1 A low melting point thermoplastic polymer adhesive: 6 kg of ethylene-vinyl acetate copolymer (purity> 98%) is heated to a molten state, and 3 kg of rosin-based tackifier is added to the molten resin, and the mixture is continuously stirred and mixed; subsequently, 0.8 kg of dioctyl phthalate plasticizer, 1.5 kg of polyethylene glycol 400, and 0.5 kg of 1010 antioxidant are added to the molten resin material and mixed evenly, and the melt is extruded through an extruder to form millimeter-sized particles, which are then cooled to obtain a low-melting-point thermoplastic polymer adhesive.

[0025] Preparation Example 2 A low melting point thermoplastic polymer adhesive: The difference from Preparation Example 1 is that the resin material is polyamide resin with a purity of >98%.

[0026] Preparation Example 3 A low melting point thermoplastic polymer adhesive: The difference from Preparation Example 1 is that the resin material is polyethylene with a purity of >98%.

[0027] Preparation Example 4 A low melting point thermoplastic polymer adhesive: The difference from Preparation Example 1 is that the resin material is thermoplastic polyurethane with a purity of >98%. Example

[0028] Example 1 A method for preparing wool felt by mixing waste wool fibers with other short fibers: Prepare waste wool fibers with a length of 2-5 cm and a diameter of 20-40 μm, soak 7.5 kg of the waste wool fibers in a 5% acetic acid solution for 10 min, mix the waste wool fibers with 2.5 kg of staple fibers to obtain 10 kg of mixed fibers, stir and mix the mixed fibers with a low-melting-point thermoplastic polymer adhesive at 55° C., and add 500 g of the low-melting-point thermoplastic polymer adhesive to obtain a mixture; in the present application, the staple fibers are selected from cotton, nylon, and PLA mixed in a mass ratio of 1:1:1, and the staple fibers have a length of 1-3 cm and a diameter of 20-30 μm; the low-melting-point thermoplastic polymer adhesive is prepared by Preparation Example 1; The mixed material is placed in a mold, and then hot-pressed and shaped by a hot pressing plate at 120° C. for 10 minutes to obtain a felt blank with a single-layer thickness of 1-1.3 mm; A melt spray granulator is used to heat a low-melting-point thermoplastic polymer adhesive to a molten state. 1000 g of the molten low-melting-point thermoplastic polymer adhesive is evenly sprayed on the surface of the felt blank through a spray device. Four felt blanks are stacked and bonded. The heating temperature is controlled at 90° C. and the curing time is 20 minutes. After the low-melting-point thermoplastic polymer adhesive is initially cured, an ultrasonic welding machine is selected to heat the fiber material locally at a heating temperature of 105° C. During the heating process, the contact points of the fiber material are partially melted, and the molten parts are tightly combined by ultrasonic vibration. The welded fiber material is visually inspected to ensure that the welded part is flat and free of cracks or bubbles. After heat pressing and shaping, use a needle punching machine to perform needle punching reinforcement on the fiber material. Set the needle punching parameters of the needle punching machine: Needle density: set to 2000 needles / ㎡; Acupuncture depth: set to 1.5 mm; Acupuncture speed: 1800 needles / minute; Acupuncture angle: 55 degrees; Needle machine pressure: 2.5MPa; After the needle punching is completed, the fiber material is sorted to remove loose fibers and impurities on the surface, and necessary trimming is performed to ensure the appearance of the material is neat and tidy to obtain wool felt.

[0029] Example 2 A method for preparing wool felt by mixing waste wool fibers with other short fibers: the difference from Example 1 is that 6 kg of waste wool fibers and 4 kg of short fibers are mixed to obtain a mixed fiber with a total weight of 10 kg.

[0030] Example 3 A method for preparing wool felt by mixing waste wool fibers with other short fibers: the difference from Example 1 is that 9 kg of waste wool fibers and 1 kg of short fibers are mixed to obtain a mixed fiber with a total weight of 10 kg.

[0031] Example 4 A method for preparing wool felt by mixing waste wool fibers with other short fibers: the difference from Example 1 is that 500 g of molten low-melting-point thermoplastic polymer adhesive is evenly sprayed on the surface of the felt blank through a spray device.

[0032] Example 5 A method for preparing wool felt by mixing waste wool fibers with other short fibers: the difference from Example 1 is that 1500 g of molten low-melting-point thermoplastic polymer adhesive is evenly sprayed on the surface of the felt blank through a spray device.

[0033] Example 6 A method for preparing wool felt by mixing waste wool fibers with other short fibers: the difference from Example 1 is that the low melting point thermoplastic polymer adhesive is prepared by Preparation Example 2.

[0034] Example 7 A method for preparing wool felt by mixing waste wool fibers with other short fibers: the difference from Example 1 is that the low melting point thermoplastic polymer adhesive is prepared by Preparation Example 3.

[0035] Example 8 A method for preparing wool felt by mixing waste wool fibers with other short fibers: the difference from Example 1 is that the low melting point thermoplastic polymer adhesive is prepared by Preparation Example 4.

[0036] Example 9 A method for preparing wool felt by mixing waste wool fibers with other short fibers: The difference from Example 1 is that the conditions for needle punching reinforcement are: needle punching density: 1000 needles / m 2 , needling depth: 1mm, needling speed: 1200 needles / minute, needling angle: 50 degrees, needling machine pressure: 1.5MPa.

[0037] Example 10 A method for preparing wool felt by mixing waste wool fibers with other short fibers: The difference from Example 1 is that the conditions for needle punching reinforcement are: needle punching density: 3000 needles / m 2 , needling depth: 2mm, needling speed: 2500 needles / minute, needling angle: 60 degrees, needling machine pressure: 3MPa.

[0038] Comparative Example Comparative Example 1 A method for preparing wool felt by mixing waste wool fibers with other short fibers: the difference from Example 1 is that the surface of the felt blanks is not sprayed with a molten low-melting-point thermoplastic polymer adhesive before the felt blanks are stacked and bonded.

[0039] Comparative Example 2 A method for preparing wool felt by mixing waste wool fibers with other short fibers: the difference from Example 1 is that the mixed fibers are not mixed with a low-melting-point thermoplastic polymer adhesive.

[0040] Comparative Example 3 A method for preparing wool felt by mixing waste wool fibers with other short fibers: the difference from Example 1 is that no local heating is performed.

[0041] Comparative Example 4 A method for preparing wool felt by mixing waste wool fibers with other short fibers: the difference from Example 1 is that no preliminary curing treatment is performed.

[0042] Performance testing Detection Methods Tensile properties: A tensile testing machine was used to test the tensile strength of the composite fiber web.

[0043] Thermal Stability: The thermal stability of the materials was measured by thermogravimetric analysis (TGA).

[0044] Table 1 Test data Tensile strength(Mpa) Thermal stability(℃) Example 1 9.56 289.6 Example 2 9.18 284.2 Example 3 9.35 281.2 Example 4 9.28 273.3 Example 5 9.47 271.2 Example 6 9.41 278.5 Example 7 9.28 289.1 Example 8 9.48 285.9 Example 9 9.16 276.8 Example 10 9.50 271.2 Comparative Example 1 7.85 263.0 Comparative Example 2 8.96 276.1 Comparative Example 3 8.40 267.5 Comparative Example 4 9.06 278.2 Combining Example 1 and Comparative Examples 1-2 and Table 1, it can be seen that spraying the molten low-melting-point thermoplastic polymer adhesive on the surface of the felt blank before the felt blanks are stacked and bonded, and mixing the mixed fibers with the low-melting-point thermoplastic polymer adhesive, has a significant effect on improving the tensile strength of the wool felt. Comparative Example 1 did not spray the adhesive on the blank surface, and Comparative Example 2 did not mix the mixed fibers with the adhesive. The tensile strengths of both were lower than those of Example 1, which shows that the bonding effect of the low-melting-point thermoplastic polymer adhesive between fibers is crucial to enhancing the structural integrity and mechanical properties of the wool felt. The lack of this link will weaken the synergistic effect between the fibers of the wool felt when it is subjected to force, thereby reducing the tensile strength, reflecting the rationality and necessity of the adhesive use method in this application.

[0045] It can be seen from Example 1 and Comparative Examples 3-4 and Table 1 that local heating and preliminary curing treatment have a certain effect on improving the thermal stability of wool felt. Comparative Example 3 did not perform local heating, and Comparative Example 4 did not perform preliminary curing treatment. The thermal stability of both was lower than that of Example 1, indicating that these steps help optimize the internal structure and chemical bonding of the wool felt, so that the material can better maintain its physical and chemical properties when heated, and reduce structural damage and performance degradation caused by temperature increase, further proving the importance of the synergistic effect of each step in the preparation process of this application for improving the comprehensive performance of wool felt.

[0046] It can be seen from Examples 1-3 and Table 1 that different mixing ratios of waste wool fibers and short fibers affect the tensile strength of wool felt. In Example 1, the tensile strength is higher at a mixing ratio of 7.5 kg of waste wool fibers and 2.5 kg of short fibers. When the ratio is changed, such as in Examples 2 and 3, the tensile strength fluctuates. This shows that a suitable fiber mixing ratio can optimize the interaction and stacking structure between fibers, so that the wool felt can more effectively disperse stress when subjected to force, thereby achieving better mechanical properties, indicating that the control of the ratio of waste wool fibers and short fibers in this application is one of the key factors in achieving high performance of wool felt.

[0047] It can be seen from Example 1 and Example 4-5 and Table 1 that the amount of low-melting-point thermoplastic polymer adhesive sprayed on the surface of the felt blank will affect the tensile strength and thermal stability of the wool felt. In Example 1, the tensile strength and thermal stability reached a certain level when 1000g was sprayed. When the spraying amount was reduced or increased, the tensile strength and thermal stability changed. This shows that the appropriate amount of adhesive sprayed can ensure good bonding between fibers while avoiding the adverse effects of too much or too little adhesive on the performance of the wool felt, which reflects the importance of precise control of the amount of adhesive in this application to achieve the optimization of the performance of the wool felt.

[0048] Combining Example 1 and Examples 6-8 with Table 1, it can be seen that the selection of different resin materials to prepare low-melting-point thermoplastic polymer adhesives will affect the performance of the wool felt. Example 1 uses ethylene-vinyl acetate copolymer, Example 6 uses polyamide resin, Example 7 uses polyethylene, and Example 8 uses thermoplastic polyurethane. There are differences in the tensile strength and thermal stability of each example, which shows that the chemical structure and performance characteristics of different resin materials will give the adhesive different properties, thereby affecting its interaction with the fiber during the preparation of the wool felt and its contribution to the overall performance of the wool felt.

[0049] It can be seen from Example 1 and Examples 9-10 and Table 1 that the needling reinforcement conditions have a significant effect on the tensile strength of the wool felt. The needling parameters of Example 1 are a needling density of 2000 needles / ㎡, a needling depth of 1.5mm, a needling speed of 1800 needles / minute, a needling angle of 55 degrees, and a needling machine pressure of 2.5MPa. When the needling density, depth, speed and pressure change, the tensile strength changes accordingly. This shows that reasonable needling reinforcement conditions can optimize the internal structure of the wool felt by changing the degree of entanglement and arrangement between fibers, thereby effectively improving its tensile strength, reflecting the important regulatory role of the needling process parameters on the mechanical properties of the wool felt in this application, and the needling parameter settings of Example 1 can enable the wool felt to achieve a relatively good tensile strength under these conditions, indicating that it is a better parameter combination.

[0050] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed. However, as long as it is within the scope of the claims of the present application, it shall be protected by the patent law.

Claims

1. A method for preparing wool felt by mixing waste wool fibers with other short fibers, characterized in that: The following steps are involved: Treating waste wool fibers in a weak acid solution for 5-10 minutes, mixing 6-9 parts by weight of the waste wool fibers with 1-4 parts of staple fibers to obtain 10 parts by weight of mixed fibers, mixing the mixed fibers with a low-melting-point thermoplastic polymer binder at 50-60° C., wherein the amount of the low-melting-point thermoplastic polymer binder added is 4-6% of the mass of the mixed fibers, to obtain a mixture; The mixed material is placed in a mold for hot pressing to obtain a felt blank with a single layer thickness of 1-1.3 mm, a low melting point thermoplastic polymer adhesive is heated to a molten state and sprayed on the surface of the felt blank, and after spraying, multiple felt blanks are stacked and bonded, and then subjected to a preliminary curing treatment, the preliminary curing temperature is 80-100° C., and the time is 15-30 minutes. After the preliminary curing treatment is completed, local heating and shaping are performed at the overlapping position of the multi-layer felt blanks, and the heating temperature is 100-110° C.; A needle punching machine is used to perform needle punching reinforcement on the felt blank after local heating and shaping. After the needle punching is completed, the surface of the felt blank is trimmed to obtain wool felt.

2. The method for preparing wool felt by mixing waste wool fibers with other short fibers according to claim 1, characterized in that: The total weight of the low melting point thermoplastic polymer adhesive in the wool felt is 10%-20% of the weight of the mixed fibers.

3. The method for preparing wool felt by mixing waste wool fibers with other short fibers according to claim 1, characterized in that: The components of the low melting point thermoplastic polymer adhesive include, by mass percentage, 60% of resin material, 30% of rosin-based tackifier, 8% of dioctyl phthalate, 0.5% of antioxidant and 1.5% of polyethylene glycol.

4. The method for preparing wool felt by mixing waste wool fibers with other short fibers according to claim 3, characterized in that: The preparation method of the low melting point thermoplastic polymer adhesive is: The resin material is heated to a molten state, a rosin-based tackifier is added to the molten resin material, and the mixture is continuously stirred and mixed; then dioctyl phthalate, polyethylene glycol and an antioxidant are added to the molten resin material and mixed evenly, the melt is extruded through a mold, and cooled to obtain a low-melting-point thermoplastic polymer adhesive.

5. The method for preparing wool felt by mixing waste wool fibers with other short fibers according to claim 3 or 4, characterized in that: The resin material is selected from one of ethylene-vinyl acetate copolymer, polyamide resin, polyethylene or thermoplastic polyurethane.

6. The method for preparing wool felt by mixing waste wool fibers with other short fibers according to claim 1, characterized in that: The staple fibers include one or more of natural fibers, synthetic fibers, and bio-based fibers.

7. The method for preparing wool felt by mixing waste wool fibers with other short fibers according to claim 1, characterized in that: The conditions for the needle punching reinforcement are needle punching density: 1000-3000 needles / m 2 , acupuncture depth: 1-2mm, acupuncture speed: 1200-2500 needles / minute, acupuncture angle: 50-60 degrees, acupuncture machine pressure: 1.5-3MPa.

8. The method for preparing wool felt by mixing waste wool fibers with other short fibers according to claim 1, characterized in that: The waste wool fibers have a length of 2-5 cm and a diameter of 20-40 μm, and the short fibers have a length of 1-3 cm and a diameter of 20-30 μm.