A composite structural felt for tennis ball outer covering and preparation method thereof

Abstract

The present invention discloses a composite structural felt for covering a tennis ball and a preparation method thereof, and belongs to the field of tennis sports products. The technical solution adopted by the present invention is that the composite structural felt for covering a tennis ball includes elastic woven fabric, elastic non-woven sheet layer, and felt in sequence from the inside to the outside at the point where the ball core is attached, and the layers are connected by needle punching to form a composite structural felt blank, and then the composite structural felt blank is post-processed. The composite structural felt obtained by the preparation method of the present invention has the advantages of reducing hair loss and reducing the "hair blasting" phenomenon caused by static electricity when the tennis ball contacts the rubber field. At the same time, the entire composite structural felt has a certain elasticity, which can slow down the phenomenon of cracking of the felt at the bonding boundary line caused by the deformation of the ball, and reduce the probability of wrinkles forming at the boundary of the composite structural felt during the bonding process.

Description

Technical Field

[0001] The invention belongs to the field of tennis sports products, and in particular relates to a composite structure felt for outer covering of a tennis ball and a preparation method thereof. Background Art

[0002] Tennis is a sport that is gradually gaining popularity in the country. Tennis is generally made of a core and an outer covering of felt.

[0003] Traditional outer covering felt is composed of a woven fabric as the inner layer and a needle-punched nonwoven fabric as the outer layer, which are compounded through a bonding process. The outer layer of needle-punched covering felt is mostly made of a mixture of wool and nylon as fiber raw materials. Since nylon and wool have large dielectric constants, according to the charging sequence, the two will be positively charged after friction with rubber. During the use of traditional tennis balls, the outer layer of wool and nylon mixed felt is positively charged after friction with the rubber field. Since the same charges repel each other, the fibers explode, forming the "explosive hair" phenomenon.

[0004] The existing process uses polyester instead of nylon and needle-punches it with wool. However, the outer covering material formed by the felt made by mixing wool and polyester fibers has lower wear resistance than nylon and lacks elasticity. After the felt is formed, the tennis ball will deform when being hit.

[0005] The inner base fabric of traditional tennis felt is cotton woven fabric, which is inelastic. Although the outer layer has wool fiber to provide elasticity, after adding polyester fiber, the elasticity is lower than that of nylon and wool mixed felt. After bonding with the tennis core, the outer felt and the ball deform differently during the deformation process, resulting in Figure 1 The two pieces of outer covering felt shown in the figure have cracks at the bonding boundary. Summary of the invention

[0006] In view of the technical problems that the existing felt for wrapping tennis balls is prone to "explosion" and cracking at the bonding boundaries, the present invention provides a composite structural felt for wrapping tennis balls with good antistatic properties, soft hand feel and low hair loss rate; another object of the present invention is to provide a method for preparing the composite structural felt for wrapping tennis balls.

[0007] In order to achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a composite structure felt for covering the outer surface of a tennis ball, wherein the composite structure felt comprises, from the inside to the outside, an elastic woven fabric, an elastic non-woven sheet layer, and a felt, and the layers are connected by a needle punching process. The elastic non-woven sheet layer is an elastic mesh structure made of heat-shrinkable elastic fibers and polyester fibers / PBT fibers through a non-woven process, and the felt is a mesh structure made of wool and modified PBT fibers through a non-woven process.

[0008] Furthermore, the mass ratio of wool to modified PBT fiber in the felt is 50-70:30-50.

[0009] Furthermore, the elastic woven fabric is a woven fabric formed by weaving a blended yarn of polyurethane fiber and cotton fiber in a mass ratio of 95-85:5-15.

[0010] Furthermore, the mass ratio of the heat-shrinkable elastic fiber to the polyester fiber / PBT fiber in the elastic non-woven sheet layer is 35-40:60-65, and the heat-shrinkable elastic fiber is chloroprene.

[0011] Furthermore, the modified PBT fiber in the felt is PBT fiber subjected to alkali weight reduction modification treatment.

[0012] A method for preparing the above-mentioned composite structure felt for outer covering of tennis ball comprises the following steps: step 1, performing alkali reduction treatment on PBT fiber to obtain modified PBT fiber; step 2, performing needle punching on wool and modified PBT fiber after opening and mixing according to a proportion to obtain felt; performing needle punching on heat shrinkable elastic fiber and polyester fiber / PBT fiber after opening and mixing according to a proportion to obtain elastic non-woven sheet layer; performing weaving on blended yarn of polyurethane fiber and cotton fiber to obtain elastic woven fabric; step 3, sequentially stacking the obtained elastic woven fabric, elastic non-woven sheet layer and felt, integrating them by needle punching to obtain composite structure felt blank; step 4, performing post-processing on the composite structure felt blank obtained in step 3 to obtain a finished product.

[0013] Furthermore, the post-finishing processing in step 4 includes heat shrinkage treatment, softening treatment, hydrophilic treatment and singeing treatment of the inner layer of the coated composite structure felt.

[0014] Furthermore, the heat shrinkage treatment is performed at a temperature of 70 to 100° C. and for a time of 1 to 2.5 hours.

[0015] Through the above technical solution, the present invention can achieve the following beneficial effects:

[0016] (1) The introduction of modified PBT fiber not only neutralizes the charge between it and wool, but also improves the wear resistance of the outer covering material of the tennis ball because PBT fiber is an elastic fiber and its wear resistance is equivalent to that of nylon. At the same time, the composite structure felt is subjected to heat shrinkage treatment. Since the elastic non-woven sheet layer in the middle layer has heat shrinkage, the surface density of the felt is increased, which reduces the "hair explosion" phenomenon caused by static electricity when the tennis ball contacts the rubber court. After heat treatment, the entire composite structure felt is made tighter, thereby reducing the hair loss phenomenon.

[0017] (2) The inner layer is an elastic woven fabric, the middle layer is an elastic non-woven sheet layer using heat-shrinkable elastic fiber and polyester fiber / PBT fiber, and the outer layer of felt is made of wool and modified PBT fiber. The three-layer structure is integrated by needle punching instead of adhesive bonding. The layers are not simply superimposed, but the fibers are interpenetrated by the needle punching process to achieve structural integration and play a synergistic role. The entire composite structure felt has a certain elasticity, which slows down the phenomenon of deformation causing the felt to crack at the bonding boundary, and reduces the probability of wrinkles forming at the boundary of the composite structure felt during bonding processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A tennis ball-like sphere;

[0019] Figure 2 A schematic cross-sectional view of the structure of the composite structure felt coated on the outer surface of a tennis ball according to the present invention;

[0020] Figure 3 It is a schematic diagram of the layered plane of the composite structure felt coated on the tennis ball of the present invention;

[0021] Among them, a is the bonding boundary of two pieces of covering structural felt, 1 is the elastic woven fabric, 2 is the elastic non-woven sheet layer, and 3 is the felt. DETAILED DESCRIPTION

[0022] The present invention is described in detail below with reference to the accompanying drawings and embodiments.

[0023] Example 1

[0024] A tennis ball outer covering composite structure felt, such as Figure 2 and Figure 3 As shown, the composite structure felt includes elastic woven fabric 1, elastic non-woven sheet 2, and felt 3 from the inside to the outside of the ball core, and the layers are connected by needle punching. The elastic non-woven sheet 2 is an elastic mesh structure made of heat-shrinkable elastic fiber and polyester fiber / PBT fiber through a non-woven process, and the felt 3 is a mesh structure made of wool and modified PBT fiber through a non-woven process. The mass ratio of wool to modified PBT fiber in felt 3 is 70:30. Elastic woven fabric 1 is a woven fabric formed by weaving a blended yarn of polyurethane fiber and cotton fiber with a mass ratio of 95:5. The mass ratio of heat-shrinkable elastic fiber to PBT fiber in elastic non-woven sheet 2 is 35:65, and the heat-shrinkable elastic fiber is chloroprene. The modified PBT fiber in felt 3 is PBT fiber subjected to alkali reduction modification treatment.

[0025] The preparation method of the composite structure felt for tennis ball outer covering comprises the following steps: step 1, alkali reduction treatment is performed on PBT fiber to obtain modified PBT fiber; step 2, wool and modified PBT fiber are opened and mixed at a mass ratio of 70:30 and needle punched to obtain felt 3; chlorofluorocarbon and PBT fiber are opened and mixed at a mass ratio of 35:65 and needle punched to obtain elastic non-woven sheet 2; polyurethane fiber and cotton fiber are blended yarn at a mass ratio of 95:5 for weaving to obtain elastic woven fabric 1; step 3, the obtained elastic woven fabric 1, elastic non-woven sheet 2 and felt 3 are stacked in sequence, and integrated by needle punching to obtain a composite structure felt blank; step 4, the composite structure felt blank obtained in step 3 is subjected to post-processing to obtain a finished product.

[0026] The modified PBT fiber in step 1 is obtained by subjecting the PBT fiber to an alkali reduction treatment at 130° C. for 1 hour using a sodium hydroxide solution having a concentration of 10 g / L. The surface density of the elastic nonwoven sheet layer 2 in step 2 is 126 g / m 2 , thickness is 0.63mm; the surface density of felt 3 is 211g / m 2 The thickness is 0.8mm. The post-processing in step 4 includes heat shrinkage treatment, softening treatment, hydrophilic treatment and singeing treatment of the inner layer of the coated composite structure felt, wherein the heat shrinkage treatment temperature is 70°C and the time is 2 hours; the inner layer of the composite structure felt is singeed to remove the fluff on the surface of the inner layer, and the entire composite structure felt is tightly bonded to the ball core; the softening treatment is performed using an alkyl quaternary ammonium salt softening agent.

[0027] The finished product obtained after the above steps is a tennis ball outer covering composite structure felt which includes elastic woven fabric 1, elastic nonwoven sheet layer 2, and felt 3 from the inside to the outside of the ball core, and the layers are connected by needle punching.

[0028] Example 2

[0029] A tennis ball outer covering composite structure felt, such as Figure 2 and Figure 3As shown, the composite structure felt includes elastic woven fabric 1, elastic non-woven sheet 2, and felt 3 from the inside to the outside of the ball core, and the layers are connected by needle punching. The elastic non-woven sheet 2 is an elastic mesh structure made of heat-shrinkable elastic fiber and polyester fiber / PBT fiber through a non-woven process, and the felt 3 is a mesh structure made of wool and modified PBT fiber through a non-woven process. The mass ratio of wool to modified PBT fiber in felt 3 is 60:40. Elastic woven fabric 1 is a woven fabric formed by weaving a blended yarn of polyurethane fiber and cotton fiber with a mass ratio of 90:10. The mass ratio of heat-shrinkable elastic fiber to PBT fiber in elastic non-woven sheet 2 is 40:60, and the heat-shrinkable elastic fiber is chloroprene. The modified PBT fiber in the felt is PBT fiber subjected to alkali reduction modification treatment.

[0030] The preparation method of the composite structure felt for tennis ball outer covering comprises the following steps: step 1, alkali reduction treatment is performed on PBT fiber to obtain modified PBT fiber; step 2, wool and modified PBT fiber are opened and mixed at a mass ratio of 60:40 and needle punched to obtain felt 3; chlorofluorocarbon and PBT fiber are opened and mixed at a mass ratio of 40:60 and needle punched to obtain elastic non-woven sheet 2; polyurethane fiber and cotton fiber are blended yarn at a mass ratio of 90:10 for weaving to obtain elastic woven fabric 1; step 3, the obtained elastic woven fabric 1, elastic non-woven sheet 2 and felt 3 are stacked in sequence, and integrated by needle punching to obtain a composite structure felt blank; step 4, the composite structure felt blank obtained in step 3 is subjected to post-processing to obtain a finished product.

[0031] The modified PBT fiber in step 1 is obtained by subjecting the PBT fiber to an alkali reduction treatment for 1 hour at 130°C using a sodium hydroxide solution having a concentration of 10 g / L. The post-finishing processing in step 4 includes heat shrinkage treatment, softening finishing, hydrophilic finishing, and singeing treatment of the inner layer of the coated composite structure felt, wherein the heat shrinkage treatment temperature is 70°C and the time is 2.5 hours; the inner layer of the composite structure felt is singeed to remove the fluff on the surface of the inner layer, and the entire composite structure felt is tightly bonded to the ball core; and the softening finishing is performed using an alkyl quaternary ammonium salt softening finishing agent.

[0032] The finished product obtained after the above steps is a tennis ball outer covering composite structure felt which includes elastic woven fabric 1, heat shrinkable elastic nonwoven sheet layer 2, and felt 3 from the inside to the outside of the ball core, and the layers are connected by needle punching.

[0033] Example 3

[0034] A tennis ball outer covering composite structure felt, such as Figure 2 and Figure 3As shown, the composite structure felt includes elastic woven fabric 1, elastic non-woven sheet 2, and felt 3 from the inside to the outside of the ball core, and the layers are connected by needle punching. The elastic non-woven sheet 2 is an elastic mesh structure made of heat-shrinkable elastic fiber and polyester fiber / PBT fiber through a non-woven process, and the felt 3 is a mesh structure made of wool and modified PBT fiber through a non-woven process. The mass ratio of wool to modified PBT fiber in felt 3 is 50:50. Elastic woven fabric 1 is a woven fabric formed by weaving a blended yarn of polyurethane fiber and cotton fiber with a mass ratio of 85:15. The mass ratio of heat-shrinkable elastic fiber to PBT fiber in elastic non-woven sheet 2 is 35:65, and the heat-shrinkable elastic fiber is chloroprene. The modified PBT fiber in the felt is PBT fiber subjected to alkali reduction modification treatment.

[0035] The preparation method of the composite structure felt for tennis ball outer covering comprises the following steps: step 1, alkali reduction treatment is performed on PBT fiber to obtain modified PBT fiber; step 2, wool and modified PBT fiber are opened and mixed at a mass ratio of 50:50 and needle punched to obtain felt 3; chlorofluorocarbon and PBT fiber are opened and mixed at a mass ratio of 35:65 and needle punched to obtain elastic non-woven sheet 2; polyurethane fiber and cotton fiber are blended yarn at a mass ratio of 85:15 and weaved to obtain elastic woven fabric 1; step 3, the obtained elastic woven fabric 1, elastic non-woven sheet 2 and felt 3 are stacked in sequence, and integrated by needle punching to obtain a composite structure felt blank; step 4, the composite structure felt blank obtained in step 3 is subjected to post-processing to obtain a finished product.

[0036] The modified PBT fiber in step 1 is obtained by subjecting the PBT fiber to an alkali reduction treatment for 1 hour at 130°C using a sodium hydroxide solution having a concentration of 10 g / L. The post-finishing processing in step 4 includes heat shrinkage treatment, softening finishing, hydrophilic finishing, and singeing treatment of the inner layer of the coated composite structure felt, wherein the heat shrinkage treatment temperature is 100°C and the time is 1 hour; singeing treatment is performed on the inner layer of the composite structure felt to remove the fluff on the surface of the inner layer, and the entire composite structure felt is tightly bonded to the ball core; and softening finishing is performed using an alkyl quaternary ammonium salt softening finishing agent.

[0037] The finished product obtained after the above steps is a tennis ball outer covering composite structure felt which includes elastic woven fabric 1, heat shrinkable elastic nonwoven sheet layer 2, and felt 3 from the inside to the outside of the ball core, and the layers are connected by needle punching.

[0038] After testing, the hair loss rate, antistatic properties, wrinkles and cracking at the boundaries of the tennis ball outer covering composite structure felt prepared in Examples 1 to 3 are shown in Table 1.

[0039] Table 1 Analysis of the hair loss rate, antistatic, wrinkle condition and cracking condition at the boundary of the composite structure felt of Examples 1 to 3

[0040]

[0041] It can be seen that the composite structure felt prepared in Examples 1 to 3 within the limited parameter range of the present invention has less hair loss and anti-static properties compared with the traditional standard tennis composite material, and can effectively reduce the hair frying phenomenon. There is no cracking at the boundary after use. In addition, since the overall composite structure felt has elasticity, it can prevent the composite structure felt from being bonded to the ball core. Figure 1 The structure a shown in the figure has wrinkles at the bonding boundary. The outer layer of felt is a mesh structure made of wool and modified PBT fibers through needle punching. The felt is compact and uniform, and has good elasticity, wear resistance and isotropic uniformity. During the process of hitting the ball, the overall composite structure felt has a certain elasticity, and the adaptability changes with the deformation of the rubber core of the tennis ball, which reduces the probability of cracking at the bonding boundary. According to the electrostatic sequence, wool and rubber are positively charged by friction, and PBT is a type of polyester fiber, which is negatively charged by friction with rubber. The charges of the two are neutralized, further reducing static electricity accumulation. The PBT fiber is subjected to alkali reduction treatment, so that the fiber surface is etched to produce pits. In addition, the 10g / L NaOH solution hydrolyzes some of the ester groups between the fiber macromolecular chains to expose polar groups, thereby improving the hydrophilicity. The overall moisture absorption rate of the felt is high, which improves the tennis ball. The "hair explosion" phenomenon of the outer felt; after the elastic non-woven sheet layer of the middle layer is treated with heat shrinkage, the outer felt layer can be further compacted as the size of the elastic non-woven sheet layer shrinks due to heat shrinkage, reducing hair loss, and can also make the elastic woven fabric of the inner layer smoother, tighter and without gaps, which is more conducive to bonding with the core; compared with the non-woven fabric, the elastic woven fabric of the inner layer is thin and crisp, providing a flat base when needle-punched with the middle and outer layers. At the same time, the side that fits the core is smooth and has less fluff, which can achieve a closer bond with the core. The good elasticity of the elastic woven fabric and the elasticity of the middle and outer layers reduce the formation of bonding wrinkle areas when the entire structural felt is bonded to the core, and during the use of tennis balls, the outer felt and the ball body deform consistently, reducing cracking at the bonding boundary.

[0042] Comparative Example 1

[0043] The difference from Example 1 is that the outer layer of felt is made from wool and nylon fibers.

[0044] Comparative Example 2

[0045] The difference from Example 1 is that the outer layer of felt is made from wool and ordinary polyester fiber.

[0046] Comparative Example 3

[0047] The difference from Example 1 is that the composite structural felt does not include the middle elastic non-woven sheet layer, that is, it is only formed by compounding the outer layer of felt and the inner layer of elastic woven fabric through a needle punching process.

[0048] Comparative Example 4

[0049] The difference from Example 1 is that the inner layer of the composite structure felt is made of ordinary non-elastic cotton woven fabric.

[0050] Comparative Example 5

[0051] The difference from Example 1 is that the elastic woven fabric, the elastic non-woven sheet layer and the felt are bonded and compounded by a traditional adhesive bonding process.

[0052] After testing, the results of the hair loss rate, antistatic, wrinkle condition and cracking condition at the boundary of the tennis ball outer covering composite structure felt prepared in Comparative Examples 1 to 5 are shown in Table 2.

[0053] Table 2 Analysis of the hair loss rate, antistatic, wrinkle condition and cracking condition at the boundary of the composite structure felt of comparative examples 1 to 5

[0054]

[0055] Compared with Example 1, the antistatic performance of Comparative Example 1 is poor. Since nylon and wool have large dielectric coefficients, they will carry positive charges after friction with the rubber field. Due to the accumulation of charges, static electricity is generated, and like charges repel each other, causing the fibers to explode, forming a "hair explosion" phenomenon, which leads to an increase in the hair loss rate during the friction process.

[0056] Compared with Example 1, Comparative Example 2 has decreased elasticity and is prone to slight cracking at the boundaries after multiple compression tests, indicating that by selecting PBT elastic fiber, which is the same polyester fiber as polyester, as the improved raw material, the wear resistance of PBT fiber is equivalent to that of nylon and it is elastic. At the same time, after the PBT fiber is rubbed with rubber, the fiber is negatively charged, and after the wool is rubbed with rubber, the wool is positively charged. The two reduce static electricity through charge neutralization to slow down the "hair frying". In addition, before the fiber is mixed and combed, the PBT fiber is subjected to alkali reduction treatment to form pits on the fiber surface, which improves the hygroscopicity of the PBT fiber, reduces the charge accumulation phenomenon, and further alleviates the "hair frying" phenomenon.

[0057] Compared with Example 1, due to the lack of an elastic nonwoven sheet layer connecting the inner elastic woven fabric and the outer felt as an elastic buffer transition layer, Comparative Example 3 is prone to slight wrinkles in the bonding area, which is inconsistent with the deformation of the outer felt, cracks appear at the bonding boundary, and the hair loss rate is high. This shows that after the middle elastic nonwoven sheet layer is heat-shrinked, it can drive the outer felt layer to be further compacted as the size of the elastic nonwoven sheet layer shrinks, and the surface density increases. At the same time, it can also make the inner woven fabric tight and gap-free, which is more conducive to bonding with the ball core.

[0058] Compared with Example 1, since the inner layer of Comparative Example 4 uses non-elastic woven fabric, it is easy to be inconsistent with the elastic deformation of the outer felt and the sphere during the deformation process, resulting in wrinkles at the bonding boundary.

[0059] Compared with Example 1, Comparative Example 5 uses adhesive bonding, and the bonding force between layers is relatively large, and delamination is not easy to occur. However, there is a lack of connection between layers through needle punching, and the elastic integration of fiber interpenetration in the three-layer structure needle punching composite process cannot be achieved, and the synergistic effect cannot be well exerted, resulting in the overall elastic connection between layers being weakened due to the curing of the adhesive, resulting in slight cracks at the bonding boundary.

[0060] The composite structure felt prepared by the present invention is tested for antistatic properties, hair loss rate, wrinkle conditions and cracking conditions at the boundary. The antistatic test method adopts the charge test method. The sample after friction by the roller friction machine is put into the Faraday cup to measure the charge of the sample. The detection index is the charge (μC). The charge (μC) <0.2 is grade A. The value of the charge (μC) is between 0.20 and 0.60, and the evaluation grade is grade B. The smaller the value of the charge, the higher the grade, indicating that the antistatic property is better. The hair loss rate test method adopts a hair removal tester. A brush that performs linear unidirectional motion and a composite structure felt blank perform linear unidirectional brushing motion. Each test part is brushed 70 times, the hair is collected and weighed, and the hair loss rate is calculated. The higher the hair loss rate value, the easier it is to lose hair. The wrinkle condition and the cracking condition at the boundary are observed and judged after multiple tennis compression tests. The compression test method is to bond the coated composite structure felt to the rubber ball core at a temperature of 20℃±1℃, a relative humidity of 60%±5%, and an atmospheric pressure of 101.3kPa±3.3kPa; perform repeated compression tests using a tennis deformation tester to simulate the deformation of a tennis ball in actual applications; avoid the rubber strips of the ball during compression, and perform rapid compression and recovery along three mutually perpendicular axes of the ball. The compression deformation size is 10mm, and each axis is repeated 2000 times. The wrinkles and boundary cracks of the tennis ball are observed with the naked eye.

Claims

1. A composite structure felt for covering a tennis ball, characterized in that: The composite structure felt comprises, from the inside to the outside at the point where the ball core is attached, an elastic woven fabric (1), an elastic non-woven sheet layer (2), and a felt (3), the layers being connected by a needle punching process; the elastic non-woven sheet layer (2) is an elastic mesh structure made of heat-shrinkable elastic fibers and polyester fibers by a non-woven process; the felt (3) is a mesh structure made of wool and modified PBT fibers by a non-woven process; the modified PBT fibers in the felt (3) are PBT fibers subjected to an alkali reduction modification process.

2. The tennis ball outer covering composite structure felt according to claim 1, characterized in that: The mass ratio of wool to modified PBT fiber in the felt (3) is 50-70:30-50.

3. The tennis ball outer covering composite structure felt according to claim 1, characterized in that: The elastic woven fabric (1) is a woven fabric formed by weaving a blended yarn of polyurethane fiber and cotton fiber in a mass ratio of 95-85:5-15.

4. The tennis ball outer covering composite structure felt according to claim 1, characterized in that: The mass ratio of the heat-shrinkable elastic fiber to the polyester fiber in the elastic non-woven sheet layer is 35-40:60-65, and the heat-shrinkable elastic fiber is chloroprene.

5. A method for preparing the composite structure felt for covering a tennis ball according to any one of claims 1 to 4, characterized in that: The steps include: Step 1, performing alkali reduction treatment on PBT fiber to obtain modified PBT fiber; Step 2, wool and modified PBT fibers are opened and mixed according to a ratio and then needle-punched to obtain felt (3); heat-shrinkable elastic fibers and polyester fibers are opened and mixed according to a ratio and then needle-punched to obtain an elastic non-woven sheet (2); blended yarns of polyurethane fibers and cotton fibers are woven to obtain an elastic woven fabric (1); Step 3, stacking the prepared elastic woven fabric (1), the elastic non-woven sheet layer (2), and the felt (3) in sequence, and integrating them by needle punching to prepare a composite structure felt blank; Step 4, subjecting the composite structure felt blank obtained in step 3 to post-processing to obtain a finished product.

6. The preparation method according to claim 5, characterized in that: The post-finishing processing in step 4 includes heat shrinkage treatment, softening treatment, hydrophilic treatment and singeing treatment of the inner layer of the coated composite structure felt.

7. The preparation method according to claim 6, characterized in that: The heat shrinkage treatment is performed at a temperature of 70 to 100° C. and for a time of 1 to 2.5 hours.

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