High-wear-resistance polyurethane synthetic leather as well as preparation method and application thereof

Abstract

The invention discloses high-wear-resistance polyurethane synthetic leather and a preparation method and application thereof.In preparation of a middle layer, after the surface of a surface layer is coated with middle layer slurry, the surface layer sequentially passes through a low-temperature orientation section and a high-temperature curing section; the middle-layer slurry contains 100 parts by mass of high-solid-content polyurethane resin with a sulfonic side chain, 0.5-2 parts by mass of a curing agent a, 1-4 parts by mass of a curing agent b and 2-6 parts by mass of an accelerant, and the onset temperature of the curing agent a is lower than that of the curing agent b; in the low-temperature orientation section, a solvent is dried at the temperature lower than T1, and meanwhile, an orientation magnetic field is arranged; the high-temperature curing section is used for realizing cross-linking curing of the surface layer and the middle layer under the condition that the temperature is not lower than T2; the temperature T1 and the temperature T2 are the deblocking temperatures of the curing agent a and the curing agent b respectively. According to the preparation method, not only is the wear resistance of the polyurethane synthetic leather improved, but also good combination of the middle layer and the foaming solvent-free bonding layer is realized, and finished leather with high peel strength is obtained.

Description

Technical Field

[0001] This application belongs to the field of polyurethane synthetic leather technology, specifically relating to a high abrasion-resistant polyurethane synthetic leather, its preparation method, and its application. Background Technology

[0002] Common soccer ball leather requires high physical properties, and currently, PVC or TPU are the main materials used. However, PVC's environmental performance, poor aging resistance, and tendency to harden at low temperatures limit its use; while TPU's application is also limited due to its significant temperature sensitivity. While current PU synthetic leather soccer balls are relatively practical, they are mainly used in everyday situations such as training or amateur matches; and even then, their use is largely limited to machine-stitched balls and ordinary 32-piece composite balls. However, for high-end competition balls, such as those used in professional sports, current PU synthetic leather cannot meet the physical performance requirements, especially in terms of abrasion resistance. To improve abrasion resistance, some PU ball leathers increase the amount of silicone oil-based additives or cross-linking agents, increasing the smoothness or cross-linking degree of the leather surface, thus affecting surface printing and processing.

[0003] Furthermore, in PU leather for soccer balls, especially for professional competitive soccer balls, high-solids-content polyurethane resin is often used to meet the requirements for physical properties and process stability. However, the poor bonding strength between high-solids-content polyurethane resin and the currently widely used solvent-free adhesive layer makes it difficult for the peel strength of soccer ball leather to meet the requirements of professional competitive soccer balls. Summary of the Invention

[0004] In view of this, the primary objective of this application is to provide a method for preparing high-abrasion-resistant polyurethane synthetic leather. This method optimizes the intermediate layer components and employs a specific intermediate layer processing technology, enabling the intermediate layer to be reverse-cured into the top layer. The intermediate layer and the top layer cross-link and cure to form a dense polyurethane composite layer, thereby improving the abrasion resistance of the polyurethane synthetic leather while maintaining the printability of the top layer polyurethane. Furthermore, the method utilizes a magnetic field to orient specific groups, addressing the problem of poor bonding between the solvent-free adhesive layer and the high-solids resin.

[0005] To achieve the above objectives, this application adopts the following technical solution: One aspect of this application discloses a method for preparing high abrasion-resistant polyurethane synthetic leather, comprising the steps of sequentially forming a top layer, an intermediate layer and a foamed solvent-free adhesive layer, and the step of bonding a base fabric to the foamed solvent-free adhesive layer to form high abrasion-resistant polyurethane synthetic leather. The intermediate layer is formed by coating the surface of the top layer with an intermediate layer slurry and then sequentially passing it through a low-temperature orientation section and a high-temperature curing section. The intermediate layer slurry, by weight, contains 100 parts of high-solids-content polyurethane resin with sulfonic acid side chains, 0.5-2 parts of curing agent a, 1-4 parts of curing agent b, and 2-6 parts of accelerator. Curing agent a is used to achieve cross-linking curing of the high-solids-content polyurethane resin, and curing agent b is used to achieve cross-linking curing between the top layer and the intermediate layer. The effective temperature of curing agent a is lower than that of curing agent b. The low-temperature orientation section dries the solvent at a temperature below T1, while simultaneously setting a directional magnetic field from the surface layer to the foamed solvent-free adhesive layer; the high-temperature curing section achieves cross-linking and curing of the surface layer and the intermediate layer at a temperature not lower than T2; temperature T1 is the desealing temperature of curing agent a, and temperature T2 is the desealing temperature of curing agent b.

[0006] Another aspect of this application discloses a high abrasion-resistant polyurethane synthetic leather, which is prepared using the preparation method described in this application.

[0007] Another aspect of this application discloses the use of high abrasion-resistant polyurethane synthetic leather, as described in this application, in the preparation of match footballs.

[0008] The beneficial effects of this application are: This application optimizes the intermediate layer slurry by introducing a high-solids-content polyurethane resin with sulfonic acid side chains. It also adds two curing agents and accelerators with different onset temperatures, and employs a specific process. Specifically, the slurry is passed sequentially through a low-temperature orientation section and a high-temperature curing section. In the low-temperature orientation section, the solvent is dried without cross-linking curing. At this stage, the solvent partially dissolves the surface layer polyurethane, activating the molecular chains. Simultaneously, the curing agent and accelerator enter the spaces between the surface layer molecular chains along with the solvent. This allows for the simultaneous curing of a portion of the surface layer resin during the subsequent high-temperature desealing and curing process, forming a dense layer between the surface layer and the intermediate layer, thereby enhancing the wear resistance of the surface layer. Furthermore, in the low-temperature orientation section, a directional magnetic field is used to adjust the sulfonic acid side chains, aligning the sulfonic acid groups towards the foamed solvent-free adhesive layer, thereby increasing the bonding strength between the intermediate layer and the foamed solvent-free adhesive layer.

[0009] The preparation method described in this application not only improves the physical properties of polyurethane synthetic leather, such as abrasion resistance and peel strength, but also maintains the printability of the surface layer, making it suitable for bonding most irregularly shaped balls and expanding the application range of polyurethane synthetic leather in the field of sports equipment. Attached Figure Description

[0010] Figure 1 This is a schematic diagram of the intermediate layer preparation process in a preferred embodiment of this application. Detailed Implementation

[0011] The embodiments of the present invention are described in detail below. The embodiments described below are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0012] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. Furthermore, unless otherwise specified, methods not specifically describing conditions or steps are conventional methods, and the reagents and materials used are commercially available.

[0013] The first aspect of this application provides a method for preparing high-abrasion-resistant polyurethane synthetic leather. The method includes the steps of sequentially forming a top layer, an intermediate layer, and a foamed solvent-free adhesive layer, and then laminating the foamed solvent-free adhesive layer to a base fabric to form the high-abrasion-resistant polyurethane synthetic leather. The preparation of the top layer and the foamed solvent-free adhesive layer, as well as the lamination of the foamed solvent-free adhesive layer to the base fabric, can all employ processes well-known in the art or independently developed, without any particular limitation.

[0014] The outstanding contribution of this application lies in the intermediate layer formation process, which introduces a high-solids-content polyurethane resin with sulfonic acid side chains into the intermediate layer slurry, along with an accelerator and two curing agents with different onset temperatures. The drying process involves a two-stage treatment, including a low-temperature orientation stage and a high-temperature curing stage. First, solvent drying is performed at a temperature lower than the unsealing temperature of curing agent a, while simultaneously using an directional magnetic field to adjust the orientation and arrangement of the sulfonic acid groups. Subsequently, the temperature is increased (not lower than the unsealing temperature of curing agent b) for drying and curing. This not only improves the wear resistance of the surface layer but also solves the problem of poor bonding between solvent-free polyurethane and high-solids-content polyurethane resin, thereby improving the peel strength.

[0015] The technical solution of this application is described in detail below.

[0016] The main steps of the preparation method of the high abrasion-resistant polyurethane synthetic leather in this application are as follows: Forming surface layer The polyurethane surface layer in this application can be prepared using conventional methods in the art, namely, mixing and stirring the raw materials to obtain a uniform and stable surface layer slurry, coating the obtained surface layer slurry onto the surface of release paper, drying and curing to obtain the polyurethane surface layer.

[0017] The composition of the surface layer paste is not particularly limited, consisting of a polyurethane main material combined with other auxiliary materials and additives, and can be adjusted according to the product performance requirements. In some specific examples of this application, the specific composition of the surface layer paste is 100 parts of high-solids-content, low-modulus polyurethane, 0-2 parts of silicone oil, 0.3-0.6 parts of leveling agent, and 0-20 parts of color paste, by weight. The silicone oil, leveling agent, and color paste can all be conventionally selected in the art, without particular limitations. The polyurethane main material uses high-solids-content, low-modulus polyurethane resin (solids content ≥35%, 3-5 MPa (100% modulus)), which allows the polyurethane resin coating to fully fill different release paper patterns, ensuring basic wear resistance requirements, while the lower modulus is more beneficial for subsequent printing processing.

[0018] Furthermore, the drying process for the surface layer is not particularly limited; any conventional drying process in the art can be used. A stepped drying process is preferred. In some specific examples of this application, the stepped drying process uses an oven with a length of 30-35m and a temperature range of 70-135℃. As a preferred example, the oven length is 30m, and the node temperatures within the oven are sequentially set to 70-90-120-130-135℃.

[0019] Forming an intermediate layer The intermediate layer of this application is formed by coating the surface of the top layer with an intermediate layer slurry. The intermediate layer slurry comprises 100 parts of high-solids-content polyurethane resin (solids content not less than 98%) with sulfonic acid side chains, 0.5-2 parts of curing agent a, 1-4 parts of curing agent b, and 2-6 parts of accelerator. Curing agent a is used for curing and crosslinking the high-solids-content polyurethane resin, and curing agent b is used for curing and crosslinking the top layer and intermediate layer. The effective temperature of curing agent a is lower than that of curing agent b. Specifically, based on conventional high-solids-content polyurethane resin, sulfonic acid side chains are added. These side chains can be desealed at high temperatures and can be oriented in a directional magnetic field, thereby improving abrasion resistance and peel strength in conjunction with the intermediate layer process of this application. It is understood that other auxiliary reagents, such as color pastes and inorganic fillers, can be added to the intermediate layer slurry as needed, and those skilled in the art can select them according to actual requirements. As a preferred example, the intermediate layer slurry is composed of 100 parts by weight of high-solids-content polyurethane resin with sulfonic acid side chains, 0.5-2 parts by weight of curing agent a, 1-4 parts by weight of curing agent b, 2-6 parts by weight of accelerator, 2-10 parts by weight of color paste, and 10-20 parts by weight of inorganic filler. There are no particular limitations on the inorganic filler; types well-known in the art, such as Al(OH)3, can be used.

[0020] In this application, the degree of cross-linking and curing between the final intermediate layer and the top layer can be adjusted by controlling the ratio of curing agent b and accelerator in the intermediate layer slurry, thereby optimizing the printability of the final leather.

[0021] In this application, the drying process of the intermediate layer involves passing the coated intermediate layer slurry sequentially through a low-temperature orientation section and a high-temperature curing section. In the low-temperature orientation section, the temperature is set below T1, and a directional magnetic field is applied (oriented from the surface layer to the foamed solvent-free adhesive layer). Temperature T1 is the desealing temperature of curing agent a. In the high-temperature curing section, the temperature is set equal to or higher than T2, where T2 refers to the desealing temperature of curing agent b. This setup ensures that when the intermediate layer slurry passes through the low-temperature orientation section, (i) the solvent is dried without cross-linking and curing occurs; and (ii) the sulfonic acid groups are oriented and aligned closer to the foamed solvent-free adhesive layer under the influence of the directional magnetic field. The process then proceeds to the high-temperature curing section for cross-linking and curing. During the low-temperature orientation section, the solvent partially dissolves the surface polyurethane layer, activating the molecular chains. Simultaneously, the curing agent and accelerator enter the molecular chains of the surface layer along with the solvent. During the high-temperature desealing and curing process, the intermediate layer simultaneously cures a portion of the surface layer resin in the reverse direction. The intermediate layer and the surface layer form a dense polyurethane layer, thereby enhancing the wear resistance of the surface layer. Specifically, curing agents A and B do not interfere with each other. Curing agent A fully cures the high-solids content resin of the surface layer, ensuring that the high-solids content resin forms a film independently in this system without affecting performance. Curing agent B, on the other hand, supplements the curing of the surface layer resin, increasing the cross-linking between the surface layer resin and the high-solids content resin. Since curing agent B enters the surface layer partially through the solvent in the second stage, the curing of the surface layer is not entirely complete, thus ensuring the post-processing performance of the surface layer. Furthermore, under the influence of the directional magnetic field, the sulfonic acid side chains align towards the foamed solvent-free adhesive layer, thereby improving the bonding strength between the intermediate layer and the subsequent foamed solvent-free adhesive layer.

[0022] As a preferred example, the drying of the intermediate layer also employs a stepped drying process. In some specific examples, the stepped drying process uses an oven with a length of 25-30m and a temperature range of 100-145℃. Specific temperature nodes can be adjusted or optimized as needed, a capability possessed by those skilled in the art. In a typical embodiment of this application, the oven length is 20+10m, and the node temperatures within the oven are sequentially set to 100-110-120-135℃ (low-temperature orientation section) and 145-145℃ (high-temperature curing section). Specifically, a magnetic field oriented towards the upper layer is added to the 100-135℃ oven. Figure 1 As shown in the diagram, the directional magnetic field interacts with the sulfonic acid side chains during the solvent drying process of this high-solids-content polyurethane resin, causing the groups to align towards the foamed solvent-free adhesive layer, thereby enhancing the bonding strength between the intermediate layer and the foamed solvent-free adhesive layer.

[0023] In this application, considering the safety of the actual operator and the effect of the magnetic field strength on the side chain groups, a directional magnetic field with a strength of 0.5-1.0T is preferably used.

[0024] A foamed, solvent-free adhesive layer is formed, and a highly abrasion-resistant polyurethane synthetic leather is obtained. In this application, the foamed solvent-free adhesive layer is formed by a foamed solvent-free adhesive slurry. Specifically, the foamed solvent-free adhesive slurry is coated on the surface of the intermediate layer, and then heated to accelerate the reaction. It should be noted that the temperature is controlled during the heating process to accelerate the reaction and foaming of the solvent-free coating, initially forming a relatively stable foamed coating while maintaining its tackiness.

[0025] The composition of the foamed solvent-free adhesive slurry is not particularly limited and can be composed of formulas well-known in the art or independently developed. In some examples of this application, the foamed solvent-free adhesive slurry mainly consists of two-component solvent-free A / B materials and a foaming agent, and other auxiliary reagents may also be added. In some specific examples, the foamed solvent-free adhesive slurry is composed of 100 parts by weight of solvent-free polyurethane A material, 10-65 parts by weight of inorganic filler, 0-1 part by weight of catalyst, 0-0.5 parts by weight of foaming agent, and 50-150 parts by weight of solvent-free polyurethane B material. The inorganic filler, accelerator, and foaming agent can be conventional compositions in the art and are therefore not particularly limited.

[0026] The specific drying method can be adjusted according to actual needs. Preferably, a two-stage stepped drying process is also adopted, with the lengths of the drying ovens used in the two-stage stepped drying process being 10~30m and 35~130m respectively, and the temperature ranges being 70~90℃ and 120~135℃. Further, in a typical embodiment of this application, the length of the first drying oven is 20 meters, and the temperature is set at 85-85-85-90-90℃, while the second drying oven is 130 meters long, and the temperature is set at 120-125-130-135-135-135℃.

[0027] In the first stage, the solvent-free polyurethane undergoes a cross-linking reaction and releases gas to form a coating with a relatively uniform pore structure. At this time, the adhesive layer still has strong adhesive properties and can be bonded to the base fabric.

[0028] In this application, there are no special requirements for the base fabric. The appropriate type of base fabric can be selected according to the requirements of the end product. As a preferred example, the high abrasion resistant polyurethane synthetic leather in this application is used to make footballs for competition. Therefore, the selected base fabric is a high-strength woven fabric with a tear strength ≥95N / 5cm and a tensile strength ≥800N / 3cm.

[0029] The specific embodiments are described in detail below. The raw material information used in the embodiments and comparative examples is as follows: Topcoat polyurethane, SA-32, Hefei Anli Polyurethane New Materials Co., Ltd.; Intermediate layer high-solids resin, JF-HSY-9041A, Zhejiang Huafeng Synthetic Resin Co., Ltd.; Curing agent a, JF-BY-100, Zhejiang Huafeng Synthetic Resin Co., Ltd.; Curing agent b, SJ1180, Shanghai Jide Chemical Co., Ltd.; Accelerator, Nx-128, Nantong Aidewang Chemical Co., Ltd.; Solvent-free A / B materials, AL-1026A / AL-5040B, Hefei Anli Polyurethane New Materials Co., Ltd. High-strength woven fabric, Lixian Fuli.

[0030] The test reference standards are as follows: GB / T 8949-2008 5.7 Determination of breaking strength of leather physical and mechanical tests; QB / T 2726-2005 Determination of abrasion resistance of leather physical and mechanical tests; GB / T 8949-2008 5.8 Determination of tear strength of leather physical and mechanical tests; GB / T 7742.1-2005 Determination of bursting strength of leather physical and mechanical tests; QB / T4672-2014 Test method for yellowing resistance of artificial leather and synthetic leather; QB / T 4671-2014 Determination of hydrolysis resistance of leather physical and mechanical tests.

[0031] Example 1 This embodiment discloses a method for preparing high abrasion-resistant polyurethane synthetic leather, the specific steps of which are as follows: According to the specified weight proportions, weigh 2 parts of 3238 silicone oil, 20 parts of white paste, and 0.4 parts of leveling agent and add them to 180 parts of surface polyurethane SA-32. Stir at 2000 rpm for 10 minutes and apply a vacuum to obtain a stable and uniform surface paste. Coat this surface paste onto release paper and dry and cure it in an oven with a length of 30m and temperature settings of 70-90-120-130-135℃ to obtain the polyurethane surface layer.

[0032] Weigh out 100 parts by weight of intermediate layer high-solids resin JF-HSY-9041A, 20 parts of Al(OH)3, 1.9 parts of curing agent JF-BY-100, 2 parts of curing agent SJ1180, 4 parts of accelerator NX-128, and 10 parts of white paste. Stir at 2000 rpm for 10 minutes and apply a vacuum to obtain a stable and uniform intermediate layer slurry. Apply this intermediate layer slurry to the surface of the polyurethane top layer. Dry the solvent in an oven above the top layer using a 20m long directional magnetic field (0.5T-1.0T) with temperature nodes set to 100-110-120-135℃. Then, cure and crosslink the top layer and intermediate layer in a 10m oven at 145-145℃ to form a dense polyurethane composite layer of the top layer and intermediate layer.

[0033] According to the weight proportions, 100 parts of solvent-free material A AL-1026A, 65 parts of inorganic filler Al(OH)3, 0.12 parts of catalyst 90C-CC, 0.14 parts of foaming agent DY-2958, and 70 parts of solvent-free polyurethane material B AL-5040B were taken and thoroughly and rapidly stirred to obtain a foamed solvent-free adhesive slurry. This slurry was then coated onto the surface of the intermediate layer and subjected to a two-stage stepped foaming and drying process. The first stage of the stepped drying process used an oven with a length of 15m and a temperature range of 85-85-85-90-90℃. The fully foamed and initially cross-linked solvent-free coating was then laminated with a high-property woven fabric. After lamination, the fabric was sent to the second stage drying and curing oven, which had a length of 130m and a temperature range of 120-125-130-135-135-135℃. The processing speed was 6 meters / min, resulting in a high-wear-resistant polyurethane synthetic leather.

[0034] This high abrasion-resistant polyurethane synthetic leather has been tested and found to have a tensile strength of 890 N / 3 cm; no pinholes were observed after 2000 abrasion cycles (H-22×1KG); a tear load of 65 N / 3 cm; and a bursting strength ≥40 Kg / cm. 2 It exhibits a yellowing resistance rating of 4 and is resistant to hydrolysis (23℃, 10% NaOH, 24H) without cracking or powdering. Its superior performance meets the requirements for polyurethane synthetic leather used in competition footballs.

[0035] Example 2 This embodiment discloses a method for preparing high abrasion-resistant polyurethane synthetic leather, the specific steps of which are as follows: According to the weight proportions, weigh 2 parts of 3238 silicone oil, 20 parts of white paste, and 0.4 parts of leveling agent and add them to 180 parts of surface polyurethane SA-32. Stir at 2000 rpm for 10 minutes and fully vacuum to obtain a stable and uniform surface paste. Coat the surface paste onto release paper and dry and cure it in an oven with a length of 30m and temperature nodes set to 70-90-120-130-135℃ to obtain the polyurethane surface layer.

[0036] Weigh out 100 parts by weight of intermediate layer high-solids resin JF-HSY-9041A, 20 parts of Al(OH)3, 1.9 parts of curing agent JF-BY-100, 4 parts of curing agent SJ1180, 6 parts of accelerator NX-128, and 10 parts of white paste. Stir at 2000 rpm for 10 minutes and apply a vacuum to obtain a stable and uniform intermediate layer slurry. Apply this intermediate layer slurry to the surface of the polyurethane top layer. Dry the solvent in an oven above the top layer using a 20m long directional magnetic field (0.5T-1.0T) with temperature nodes set to 100-110-120-135℃. Then, cure and crosslink the top layer and intermediate layer in a 10m oven at 145-145℃ to form a dense polyurethane composite layer of the top layer and intermediate layer.

[0037] According to the weight proportions, 100 parts of solvent-free material A AL-1026A, 65 parts of inorganic filler Al(OH)3, 0.12 parts of catalyst 90C-CC, 0.14 parts of foaming agent DY-2958, and 70 parts of solvent-free polyurethane material B AL-5040B were weighed and thoroughly and rapidly stirred to obtain a foamed solvent-free adhesive slurry. This slurry was then coated onto the surface of the intermediate layer using a two-stage stepped foaming and drying process. The first stage of the stepped drying process used an oven with a length of 15m and a temperature range of 85-85-85-90-90℃. The fully foamed and initially cross-linked solvent-free coating was then laminated with a high-property woven fabric. After lamination, the fabric was sent to the second stage drying and curing oven, which had a length of 130m and a temperature range of 120-125-130-135-135-135℃. The processing speed was 6 meters / min, resulting in high-wear-resistant polyurethane synthetic leather.

[0038] This high abrasion-resistant polyurethane synthetic leather has been tested and found to have a tensile strength of 950 N / 3 cm; no pinholes were observed after 2000 abrasion cycles (H-22×1KG); a tear load of 65 N / 3 cm; and a bursting strength ≥42 Kg / cm. 2 It exhibits a yellowing resistance rating of 4 and is resistant to hydrolysis (23℃, 10% NaOH, 24H) without cracking or powdering. Its superior performance meets the requirements for polyurethane synthetic leather used in competition footballs.

[0039] Example 3 This embodiment discloses a method for preparing high abrasion-resistant polyurethane synthetic leather, the specific steps of which are as follows: According to the weight proportions, weigh 2 parts of 3238 silicone oil, 20 parts of white paste, and 0.4 parts of leveling agent and add them to 180 parts of surface polyurethane SA-32. Stir at 2000 rpm for 10 minutes and fully vacuum to obtain a stable and uniform surface paste. Coat the surface paste onto release paper and dry and cure it in an oven with a length of 30m and temperature nodes set to 70-90-120-130-135℃ to obtain the polyurethane surface layer.

[0040] Weigh out 100 parts by weight of intermediate layer high-solids resin JF-HSY-F9041A, 20 parts by weight of Al(OH)3, 1.9 parts by weight of curing agent JF-BY-100, 3 parts by weight of curing agent SJ1180, 3 parts by weight of accelerator NX-128, and 10 parts by weight of white paste. Stir at 2000 rpm for 10 minutes and apply vacuum thoroughly to obtain a stable and homogeneous intermediate layer slurry. Apply this intermediate layer slurry to the surface of the polyurethane top layer. Dry the solvent in an oven above the top layer using a 20m long directional magnetic field with temperature nodes set to 100-115-130-135℃. Then cure and crosslink the top layer and intermediate layer in a 10m oven at 145-150℃ to form a dense polyurethane composite layer of the top layer and intermediate layer.

[0041] According to the weight proportions, 100 parts of solvent-free material A AL-1026A, 65 parts of inorganic filler Al(OH)3, 0.12 parts of catalyst 90C-CC, 0.14 parts of foaming agent DY-2958, and 70 parts of solvent-free polyurethane material B AL-5040B were weighed and thoroughly and rapidly stirred to obtain a foamed solvent-free adhesive slurry. This slurry was then coated onto the surface of the intermediate layer using a two-stage stepped foaming and drying process. The first stage of the stepped drying process used an oven with a length of 15m and a temperature range of 80-80-80-85-85℃. The fully foamed and initially cross-linked solvent-free coating was then laminated with a high-performance woven fabric. After lamination, the fabric was sent to the second stage drying and curing oven, which had a length of 130m and a temperature range of 120-125-130-135-140-140℃. The processing speed was 7 meters / min, resulting in a high-wear-resistant polyurethane synthetic leather.

[0042] This high abrasion-resistant polyurethane synthetic leather has been tested and found to have a tensile strength of 900 N / 3 cm; no pinholes were observed after 2000 abrasion cycles (H-22×1KG); a tear load of 60 N / 3 cm; and a bursting strength ≥40 Kg / cm. 2 It exhibits a yellowing resistance rating of 4 and is resistant to hydrolysis (23℃, 10% NaOH, 24H) without cracking or powdering. Its superior performance meets the requirements for polyurethane synthetic leather used in competition footballs.

[0043] Comparative Example 1 This comparative example discloses another method for preparing polyurethane synthetic leather, which adopts the same implementation method as Example 1, except that 2 parts of curing agent SJ1180 and 4 parts of accelerator NX-128 are not added to the intermediate layer slurry. Other compositions, process steps and parameter conditions remain the same as in Example 1.

[0044] This high abrasion-resistant polyurethane synthetic leather has been tested and found to have a tensile strength of 800 N / 3 cm; abrasion resistance (H-22×1KG) of 2000 cycles to prevent surface breakage; tear load of 65 N / 3 cm; and bursting strength ≥42 Kg / cm. 2Yellowing resistance level 4; hydrolysis resistance (23℃, 10% NaOH, 24H) without cracking or powdering, but poor performance and does not meet the requirements for polyurethane synthetic leather for competition footballs.

[0045] Comparative Example 2 This comparative example discloses another method for preparing polyurethane synthetic leather, which adopts the same implementation method as Example 1, except that the final high-temperature curing stage of 145-145°C is omitted in the step of forming the intermediate layer. Other process steps and parameter conditions remain consistent with Example 1.

[0046] This high abrasion-resistant polyurethane synthetic leather has been tested and found to have a tensile strength of 850 N / 3 cm; abrasion resistance (H-22×1KG) of 2000 cycles to prevent surface breakage; tear load of 65 N / 3 cm; and bursting strength ≥42 Kg / cm. 2 Yellowing resistance level 4; hydrolysis resistance (23℃, 10% NaOH, 24H) without cracking or powdering, but poor performance and does not meet the requirements for polyurethane synthetic leather for competition footballs.

[0047] Comparative Example 3 This comparative example discloses another method for preparing polyurethane synthetic leather, which adopts the same implementation method as Example 1, except that a directional magnetic field is not introduced in the step of forming the intermediate layer. Other process steps and parameter conditions remain consistent with Example 1.

[0048] This high abrasion-resistant polyurethane synthetic leather has been tested and found to have a tensile strength of 890 N / 3 cm; no pinholes were observed on the leather surface after 2000 abrasion cycles (H-22×1KG); a tear load of 65 N / 3 cm; and a bursting strength ≥42 Kg / cm. 2 It exhibits a yellowing resistance rating of 4 and hydrolysis resistance (23℃, 10% NaOH, 24H) without cracking or powdering. However, during peel testing, the solvent-free coating and high-solids coating delaminated, failing to meet the requirements for polyurethane synthetic leather used in competition footballs.

[0049] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0050] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for preparing high abrasion-resistant polyurethane synthetic leather, characterized in that, The process includes the steps of sequentially forming a top layer, an intermediate layer, and a foamed solvent-free adhesive layer, as well as the step of bonding a base fabric to the foamed solvent-free adhesive layer to form a high-abrasion-resistant polyurethane synthetic leather. The intermediate layer is formed by coating the surface of the top layer with an intermediate layer slurry and then passing it sequentially through a low-temperature orientation section and a high-temperature curing section. By weight, the intermediate layer slurry contains 100 parts of high-solids polyurethane resin with sulfonic acid side chains, 0.5-2 parts of curing agent a, 1-4 parts of curing agent b, and 2-6 parts of accelerator. The effective temperature of curing agent a is lower than that of curing agent b. The low-temperature orientation section dries the solvent at a temperature below T1 while simultaneously setting a directional magnetic field from the surface layer to the foamed solvent-free adhesive layer; the high-temperature curing section achieves cross-linking curing of the surface layer and the intermediate layer at a temperature not lower than T2; wherein, temperature T1 is the desealing temperature of curing agent a, and temperature T2 is the desealing temperature of curing agent b.

2. The preparation method according to claim 1, characterized in that, The surface layer is formed by a surface layer slurry, which is composed of 100 parts by weight of high solids content and low modulus polyurethane resin, 0-2 parts by weight of silicone oil, 0.3-0.6 parts by weight of leveling agent and 0-20 parts by weight of color paste.

3. The preparation method according to claim 1, characterized in that, The surface layer adopts a stepped drying process, wherein the length of the drying oven used in the stepped drying process is 30~35m and the temperature range is 90~135℃.

4. The preparation method according to claim 1, characterized in that, The intermediate layer slurry is composed of 100 parts of high-solids polyurethane resin with sulfonic acid side chains, 0.5-2 parts of curing agent a, 1-4 parts of curing agent b, 2-6 parts of accelerator, 2-10 parts of color paste and 10-20 parts of inorganic filler in parts by weight.

5. The preparation method according to claim 1, characterized in that, The foamed solvent-free adhesive layer is formed by a foamed solvent-free adhesive slurry; the foamed solvent-free adhesive slurry is composed of 100 parts by weight of solvent-free polyurethane A, 10-65 parts by weight of inorganic filler, 0-1 parts by weight of catalyst, 0-0.5 parts by weight of foaming agent and 50-150 parts by weight of solvent-free polyurethane B.

6. The preparation method according to claim 1, characterized in that, The foamed solvent-free adhesive layer is 100% to 150% of its wet film thickness.

7. The preparation method according to claim 1, characterized in that, The foamed solvent-free adhesive layer adopts a two-stage stepped drying process. The lengths of the ovens used in the two-stage stepped drying process are 10~30m and 35~130m respectively, and the temperature ranges are 70~90℃ and 120~135℃ respectively.

8. The preparation method according to claim 1, characterized in that, The base fabric is a woven fabric substrate; Preferably, the woven fabric substrate has a tear strength ≥95N / 5cm and a tensile strength ≥800N / 3cm.

9. A high-wear-resistant polyurethane synthetic leather, characterized in that, It is prepared by the preparation method according to any one of claims 1-8.

10. The application of the high abrasion-resistant polyurethane synthetic leather as described in claim 9 in the preparation of match footballs.

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