SEBS-based synthetic leather and manufacturing method thereof

Abstract

The invention belongs to the technical field of synthetic leather production, and particularly relates to SEBS-based synthetic leather and a manufacturing method thereof. The preparation method comprises the following steps: mixing SEBS, a plasticizer, a filler, a stabilizer and a coloring agent, granulating, directly coating a cloth substrate with the granulated SEBS particles through a tape casting process, cooling, curing, carrying out molding surface treatment, and carrying out suction line cutting to obtain a finished product. According to the method, a special tape casting process and a specific material ratio are adopted, so that the SEBS-based synthetic leather has the excellent properties that the elongation at break is high, the flexibility is good, the radial direction can reach 51%-72%, and the weft direction can reach 75%-98%; the peel strength reaches 50-64N, and the interface bonding is strong; the scratch resistance grade is 4-5 grade, the Taber weight loss is less than 50mg / 1000 times, and the wear resistance is good; no harmful substance is released, the recycling rate is over 95 percent, and the environment-friendly advantage is obvious; the inter-batch elastic modulus fluctuation is lt; and the quality is stable. Compared with traditional PVC / PU synthetic leather, the PVC / PU synthetic leather effectively solves the problems of poor flexibility, no environmental protection, unstable performance and the like, and is widely applied to the fields of textiles, shoe materials, automotive interiors and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of synthetic leather production, and particularly relates to a synthetic leather based on SEBS and a manufacturing method thereof. Background Art

[0002] Currently, in the fields of textiles, shoe materials, and automotive interiors, synthetic leather has been widely used as a key material on a large scale. Traditional processes mainly rely on polyvinyl chloride (PVC) and polyurethane (PU) systems, but their inherent defects are significant. At the molecular level, the PVC molecular structure contains chlorine atoms, which will be released in the form of chlorine-containing compounds during processing, polluting the atmosphere and water bodies. At the same time, the chemical stability of the PVC molecular chain is poor. Under the action of external environmental factors such as light, heat, and oxygen, the molecular chain is prone to chemical reactions such as breaking and crosslinking, resulting in the aging of the finished product. For example, PVC synthetic leather used for car seats shows hardening and cracking phenomena in a short period. In addition, the molecular chain of PVC material has a large rigidity and insufficient flexibility, which makes the wearing comfort of clothing products poor and difficult to meet the needs of human dynamic activities.

[0003] In recent years, styrene-ethylene-butene-styrene block copolymer (SEBS) has attracted much attention due to its unique molecular design. In the molecular structure of SEBS, the main chain is an ethylene-butene flexible segment (EB), which has good elastic deformation ability. From the perspective of molecular dynamics, the carbon-carbon single bonds in the ethylene-butene flexible segment can rotate freely, enabling the molecular chain to undergo a large degree of stretching and bending when stressed, thus endowing the material with excellent elasticity and being able to withstand complex stress without easy fracture. Its terminal polystyrene (PS) hard segment forms a "molecular rivet" structure through physical crosslinking. At the microscopic level, the polystyrene hard segments interact with each other through van der Waals forces and hydrogen bonds to form a network-like structure, which can effectively restrict the relative sliding of the molecular chains and significantly improve the creep resistance and durability of the material. At the same time, the polystyrene hard segment has a certain absorption and scattering effect on ultraviolet light, endowing SEBS with excellent resistance to ultraviolet aging characteristics. In addition, SEBS does not release harmful substances throughout its life cycle, meeting the concept of green manufacturing and providing an ideal substrate for the development of high-performance synthetic leather.

[0004] In the prior art, Patent CN102717533A proposed a preparation process for an environmentally friendly outdoor sofa leather. The base cloth is formed by coating a water-soluble glue or a hot-melt glue on the base fabric and drying it at 60-150°C. Although this technology realizes zero solvent emissions and recycling of scraps, it has obvious limitations. Analyzing from the molecular level, after the adhesive cures, the molecules of the adhesive and the synthetic leather material are mainly combined in a physical adsorption manner. This combination method results in a relatively high surface hardness of the product, insufficient scratch resistance and wear resistance. At the same time, the interaction between the adhesive molecules and the molecules of the base cloth and the surface layer material is weak. The interface bonding between the base cloth and the surface layer material is mainly physical bonding, and delamination is likely to occur during long-term use. Moreover, the presence of the glue layer changes the molecular distribution on the material surface, making it difficult for the finished product to meet the requirements of the high-end textile field in terms of softness and skin-friendliness.

[0005] Yu developed a composite thermoplastic elastomer synthetic leather using dynamic vulcanization technology (《Chem Eng Equip》2021; 1(1): 7-13)). Through the synergy of multiple components such as ethylene-propylene rubber (EPDM), random copolymer polypropylene (PP), and ethylene-octene copolymer (POE), combined with a dynamic vulcanizing agent to construct a "sea-island" structure, the material has both a tensile strength of 22.86 MPa and an elongation at break of 353.95%, the low-temperature resistance is extended to -30°C, and the yellowing resistance grade reaches above level 4. However, there is still room for optimization in this technical system: First, the sensitivity of the vulcanization system is prominent. The dosage of crosslinking agents such as sulfur and phenolic resin needs to be precisely controlled within the range of 1.5-2.0 phr. Excessive dosage will cause non-linear attenuation of mechanical properties. This is because the crosslinking agent will react with rubber molecules during vulcanization to form crosslinking bonds. Excessive crosslinking agent will lead to too high a crosslinking density and a decrease in the flexibility of molecular chains, thus reducing the mechanical properties of the material. Second, dynamic vulcanization needs to be completed at a high temperature of 180-220°C and a high shear rate of 60 r / min, which requires strict wear resistance and temperature control accuracy of the internal mixer, resulting in increased energy consumption and maintenance costs. Third, the error tolerance of the rubber-plastic ratio (such as SEBS:PP = 80:20) is low. A ±5% ratio fluctuation will cause a significant change in the elastic modulus, restricting the stability of industrial production. This is because different rubber-plastic ratios will affect the interaction between molecular chains and the microstructure in the material, and thus affect the macroscopic properties of the material. Fourth, the use of a sulfur-based crosslinking system leads to the emission of VOCs and the risk of heavy metal residues, posing potential environmental pollution hazards.

[0006] In summary, although the current synthetic leather manufacturing technology has made certain progress, there are still problems such as insufficient scratch and wear resistance, poor softness, poor skin-friendliness, and potential environmental pollution hazards of the products; in terms of the preparation process, the requirements for process control are too strict, and a slight oversight will affect the performance of the final product, which urgently needs to be further improved and perfected. Summary of the Invention

[0007] To solve the problems of the prior art, the present invention provides a synthetic leather based on SEBS and a manufacturing method thereof. Through special material ratios and specific technological processes, a synthetic leather with good flexibility, strong scratch and wear resistance, and environmental friendliness is produced.

[0008] A synthetic leather based on SEBS is made by directly coating granulated SEBS particles onto a fabric substrate using a casting process. The recycling rate of the synthetic leather based on SEBS is > 95%, the radial elongation at break is 51% - 72%, the weft elongation at break is 75% - 98%, the peel strength is 50 - 64 N, the scratch resistance grade is 4 - 5, the Taber weight loss < 50 mg / 1000 times, the fluctuation of the elastic modulus between batches < 5%, the Shore A is 55 - 80, and the touch is close to that of genuine leather. The specific technical solutions are as follows:

[0009] The present invention also provides a manufacturing method of the aforementioned synthetic leather based on SEBS, including the following steps:

[0010] Step 1, granulation of the SEBS mixture

[0011] Mix 10 - 40 parts of SEBS, 10 - 40 parts of plasticizer, 10 - 40 parts of filler, 0.2 - 3 parts of stabilizer, and 0.2 - 3 parts of colorant evenly at 10 - 100 °C to obtain a mixture. Melt the mixture in a granulator at a temperature of 110 - 210 °C, and then extrude it through the nozzle of the granulator to form granular materials. The operating pressure of the granulator nozzle is 1 - 5 MPa; Cool the granular materials through a cooling water tank or air cooling at a temperature of 10 - 60 °C for 1 - 3 min to obtain granulated SEBS particles after solidification, and then dry the granulated SEBS particles to ensure no moisture;

[0012] The plasticizer is one or a mixture of two of white mineral oil and liquid paraffin. The long-chain hydrocarbon groups in its molecules interact with the SEBS molecular chains through van der Waals forces, increasing the distance between the molecular chains, weakening the intermolecular forces, increasing the mobility of the molecular chains, making the movement of the molecular chains more free, and thus improving the fluidity and flexibility of SEBS; The addition of the filler is to improve the mechanical properties of the synthetic leather and reduce costs;

[0013] The filler is a mixture obtained by the compounding process of calcium carbonate and polyolefin. The compounding process uses the coupling agent coating method for calcium carbonate, and the coupling agent is any one of silane coupling agents and titanate coupling agents; the filler significantly enhances the mechanical properties of the material. The coupling agent promotes the close combination of calcium carbonate and polyolefin to form a composite system. Calcium carbonate, as a rigid particle, effectively disperses stress, greatly improving the hardness and wear resistance of the material. The good toughness of polyolefin compensates for the brittleness of calcium carbonate, enhancing the impact resistance and tensile strength of the material; the filler also improves the processing performance. The coupling agent makes calcium carbonate disperse more uniformly in SEBS, reducing the melt viscosity and increasing the fluidity, which is not only beneficial to the molding processing of the material but also ensures the coating quality; at the same time, this process enhances the interfacial bonding force between calcium carbonate and SEBS. The coupling agent tightly connects the two like a bridge, effectively preventing the separation of the filler from the matrix, ensuring the structural stability of the material, and improving the durability of the material; in addition, by appropriately adding calcium carbonate with a lower cost and adjusting the compounding ratio of calcium carbonate and polyolefin, when the mass ratio of calcium carbonate to polyolefin is 20:(40 - 80), the density of the material can be adjusted, taking into account the cost and processing performance while ensuring the mechanical properties of the material. While reducing the cost, it meets the requirements of different scenarios, further expanding the application range of SEBS-based synthetic leather;

[0014] The stabilizer is a mixture of one or two of antioxidants and light stabilizers, used to improve the aging resistance of SEBS, and is selected from any one of bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate, antioxidant H3302 for nylon polymerization, light antioxidant stabilizer P-334, and pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]; the main purpose of adding the stabilizer is to improve the aging resistance of SEBS. The antioxidant can inhibit the oxidation reaction of SEBS with oxygen during processing and use. In the oxidation reaction, oxygen molecules will act on the SEBS molecular chain, resulting in the breakage and degradation of the molecular chain. The antioxidant can react with oxygen preferentially, consuming oxygen, thereby protecting the SEBS molecular chain from oxidation; the light stabilizer can absorb or reflect ultraviolet rays, reducing the damage of ultraviolet rays to the SEBS molecular chain. Ultraviolet rays have high energy and can break the chemical bonds in the molecular chain, resulting in a decline in material properties. The light stabilizer converts the energy of ultraviolet rays into other forms of energy through its own molecular structure or reflects ultraviolet rays, avoiding its direct action on the SEBS molecular chain, thereby extending the service life of the synthetic leather;

[0015] Step 2: Coat the granulated SEBS particles onto the fabric substrate by the casting process

[0016] Add the granulated SEBS particles described in Step 1 into a casting machine and heat them to a molten state at a temperature of 130 - 230 °C. Then, directly and evenly coat them onto the fabric substrate through the casting process using the casting machine to obtain a fabric substrate coated with SEBS. The operating pressure of the die head of the casting machine is 1 - 18 MPa, the speed is 3 - 30 m / min, and the coating thickness is controlled to be 20 - 200 μm to ensure uniform coating of the SEBS layer and consistent film thickness.

[0017] During the casting process, the molten SEBS can fully penetrate into the fiber gaps of the fabric substrate under the push of pressure. The SEBS molecular chains diffuse into the fiber gaps under the action of pressure and physically entangle and interact with the molecules on the fiber surface. When the SEBS cools and solidifies, this physical entanglement and interaction form a mechanical anchoring effect, which greatly enhances the bonding force between the SEBS layer and the fabric substrate, just like countless tiny "hooks" tightly connecting the two together. At the same time, by precisely controlling parameters such as the temperature, pressure, and speed of the casting machine, the fluidity of the SEBS melt and the uniformity of coating can be ensured, thereby ensuring uniform coating of the SEBS layer and consistent film thickness, providing a guarantee for the high-quality production of synthetic leather.

[0018] Step 3: Cooling and solidifying

[0019] Cool and solidify the fabric substrate coated with SEBS through a cooling roller. The cooling roller equipment cools the molten SEBS layer through contact and conduction, making it solidify and tightly bond with the fabric substrate. The peel strength reaches 30 - 80 N to obtain a primary finished product of SEBS synthetic leather. During the cooling and solidifying process, the temperature of the cooling roller is 5 - 60 °C and the speed is 3 - 25 m / min to ensure uniform solidification of the SEBS layer and avoid cracking or deformation.

[0020] During the cooling process, the movement of the SEBS molecular chains gradually slows down, and the intermolecular forces gradually increase. As the temperature decreases, the SEBS molecular chains will gradually arrange regularly to form a certain crystalline structure. By controlling the temperature and speed of the cooling roller, the crystallinity of SEBS and the arrangement of the molecular chains can be precisely adjusted. A lower cooling temperature and a slower cooling speed are conducive to forming a more regular crystalline structure, which can improve the hardness and wear resistance of the synthetic leather because the regular crystalline structure makes the bonding between the molecular chains closer, and it can better resist deformation and wear when subjected to external forces. While a higher cooling temperature and a faster cooling speed will make the molecular chain arrangement more disordered, which can improve the flexibility of the synthetic leather. Through the optimization of the cooling process parameters in the present invention, the synthetic leather has good flexibility while ensuring a certain hardness and wear resistance, meeting the requirements of different application scenarios.

[0021] Step 4: Perform shaping and surface treatment

[0022] First, the surface of the primary SEBS-based synthetic leather product is subjected to corona treatment 3-5 times using a corona machine with a power of 6-10 kW, and the corona time for each treatment is 5-15 s. Then, a synthetic leather surface treatment agent and additives are used to roll coat / spray the surface of the primary SEBS-based synthetic leather product, and then dried to obtain the SEBS synthetic leather after completion of shaping and surface treatment; through one-time corona treatment, the surface polarity and roughness of the primary SEBS-based synthetic leather product are increased, the adhesion of the subsequent surface treatment agent is increased, and then a synthetic leather surface treatment agent and additives are used to roll coat / spray the surface of the primary SEBS-based synthetic leather product, and then dried in an oven at 80-190 °C for 50-600 s to obtain the SEBS synthetic leather after completion of shaping and surface treatment;

[0023] Corona treatment is an efficient surface modification technology. During corona treatment, the plasma generated by high-voltage discharge has a strong interaction with the SEBS molecules on the surface of the synthetic leather. At the molecular level, the high-energy particles in the plasma impact the SEBS molecules on the surface of the synthetic leather, causing the molecular chains to break and generating a large number of free radicals. These free radicals are highly reactive and can quickly react with oxygen in the air to form various oxygen-containing polar groups on the surface, such as hydroxyl groups and carbonyl groups. The introduction of these polar groups greatly increases the surface polarity; at the same time, the impact of the plasma also causes changes in the microscopic structure of the surface, making the originally smooth surface become rougher and increasing the surface area. The increase in surface polarity and surface area both provide more sites and stronger forces for the adhesion of the surface treatment agent, thus significantly improving the adhesion of the surface treatment agent;

[0024] There is a rich variety of surface treatment agents and additives for synthetic leather, each with unique functions. The finishing agent can improve the appearance of synthetic leather, giving it a more beautiful luster and rich colors; the softening agent can further reduce the surface hardness of synthetic leather, enhance its softness and skin-friendly property, providing users with a better tactile experience; the waterproof / anti-stain agent can form a protective film with a special structure on the surface of synthetic leather, which can prevent the intrusion of moisture and stains, endowing synthetic leather with good waterproof and anti-stain properties; the filler can increase the thickness and weight of synthetic leather while improving its mechanical properties, enhancing the strength and stability of the material; the dyeing agent can endow synthetic leather with various different colors to meet the market's demand for diverse product colors; the anti-corrosion / anti-mildew agent can inhibit the growth and reproduction of microorganisms on the surface of synthetic leather, preventing synthetic leather from being damaged by microbial erosion during use; the flame retardant can improve the flame retardant performance of synthetic leather. In case of dangerous situations such as fires, it can delay the spread of fire, safeguarding people's lives and property; the antistatic agent can reduce the accumulation of static electricity on the surface of synthetic leather, avoiding problems such as dust adsorption or electric shock caused by static electricity. These surface treatment agents and additives further enhance the comprehensive performance of synthetic leather through their interactions with SEBS molecules, such as physical adsorption, chemical bonding, etc.

[0025] Step 5: Grain pattern treatment and cutting

[0026] The SEBS synthetic leather after forming and surface treatment in Step 4 should be naturally cooled, and then subjected to grain pattern treatment by a vacuum grain pattern machine to obtain the patterned SEBS synthetic leather, which is cut and trimmed as required to obtain the finished SEBS-based synthetic leather product.

[0027] Furthermore, the granulation of the SEBS mixture in Step 1 can also be carried out by an extruder under the same conditions to obtain the granulated SEBS particles, providing more options for the granulation process. In actual production, the granulation method can be flexibly selected according to the equipment situation and production requirements.

[0028] Furthermore, in Step 1, the molecular weight of the SEBS is in the range of 50,000 - 400,000. The appropriate molecular weight range is crucial for the performance of SEBS. When the molecular weight is relatively low, the molecular chains of SEBS are short, and the intermolecular forces are relatively weak, which will result in poor strength and durability of the material and cannot meet the requirements of synthetic leather in actual use; while when the molecular weight is too high, although the strength and durability of the material will be improved, the overly long molecular chains will cause more serious entanglement between molecules, leading to a significant increase in processing difficulty. Higher temperatures and pressures are required to achieve the processing process, which not only increases production costs but may also have an adverse impact on the material's performance.

[0029] Further, in step 1, the diameter of the granular material is 1-3 mm. This particle size range is of great significance for ensuring the uniformity of the fluidity of the casting melt. If the particle diameter is too large, during the casting process, the friction between particles will increase, resulting in poor melt fluidity, making it difficult to uniformly coat on the fabric substrate, and prone to problems such as uneven coating and inconsistent thickness. If the particle diameter is too small, dust is easily generated during the granulation process, which will not only affect the production environment but also may cause particle agglomeration, similarly affecting the fluidity of the casting melt and the product quality.

[0030] Further, in step 1, the polyolefin in the filler is one or more mixtures of polyethylene and polypropylene. Polyethylene and polypropylene have good toughness and processing properties. After being compounded with calcium carbonate, they can enhance the flexibility and impact resistance of the material while improving the hardness and wear resistance of the material, meeting the performance requirements of synthetic leather in different application scenarios.

[0031] Further, in step 1, the colorant is a masterbatch with SEBS as the carrier.

[0032] Further, in step 1, the colorant is a color powder with SEBS as the carrier.

[0033] Further, in step 1, the plasticizer is a mixture of one or two of mineral oil and aromatic oil, used to improve the fluidity and flexibility of SEBS. Mineral oil and aromatic oil have low viscosity and good solubility, which can effectively reduce the interaction between SEBS molecular chains, improve its fluidity and flexibility, and make SEBS easier to form during processing.

[0034] Further, in step 2, the fabric substrate is one of polyester cloth, non-woven fabric, cotton cloth or nylon cloth.

[0035] Further, in step 4, the corona treatment is to smoothly introduce the primary SEBS-based synthetic leather product into the corona machine, ensure that the material has no wrinkles, keep the tension value of the constant traction force at 5-15 N / m, adjust the distance between the discharge electrode and the surface of the primary SEBS-based synthetic leather product to 1-2.5 mm, the treatment speed is 8-20 m / min, and the discharge intensity is 50-150 W·min / m 2; In this process, precise control of parameters is crucial. If the tension value is too small, the synthetic leather may become slack during the corona treatment process, resulting in uneven surface treatment. If the tension value is too large, the synthetic leather may be stretched and deformed, affecting its physical properties. The distance between the discharge electrode and the surface of the synthetic leather determines the intensity of the interaction between the plasma and the material surface. If the distance is too close, it may cause over-treatment of the surface and damage the material. If the distance is too far, the treatment effect will be poor. The treatment speed and discharge intensity are also interrelated. A suitable combination of treatment speed and discharge intensity can generate an appropriate amount of free radicals and polar groups on the surface of the synthetic leather, effectively improving the adhesion of the surface treatment agent without negatively affecting the bulk properties of the material.

[0036] Further, in step 4, the surface treatment agent for synthetic leather is any one or a mixture of two or more of a finishing agent, a softening agent, a waterproof / anti-fouling agent, a filler, a dye, an anti-corrosion / mildew-proof agent, a flame retardant, an antistatic agent, and a UV stabilizer.

[0037] Further, in step 4, the surface auxiliary agent for synthetic leather includes any one or a mixture of two or more of a film-forming agent, a leveling agent, a plasticizer, a matting agent, an antistatic agent, a cross-linking agent, and a wetting and dispersing agent.

[0038] Further, in step 5, the embossing treatment of the SEBS synthetic leather surface is carried out by rolling, vacuum embossing, printing, hot pressing, and laser engraving on the SEBS synthetic leather surface to form a leather texture effect and form antibacterial, mildew-proof, flame-retardant, patterned, anti-fouling, wear-resistant, scratch-resistant, and skin-friendly functional effects;

[0039] Rolling embossing uses a roller with a specific texture to apply pressure on the surface of the synthetic leather to form corresponding textures on the surface of the synthetic leather. This method is simple to operate and has a low cost, and is suitable for large-scale production. Vacuum embossing is to adsorb the synthetic leather on a mold with a texture through vacuum suction to form a realistic leather texture, which can better simulate the texture details of natural leather. Printing embossing can print various beautiful patterns and textures on the surface of the synthetic leather to enrich the appearance effect of the product. Hot pressing embossing uses high temperature and high pressure to closely fit the surface of the synthetic leather with the mold texture to form a firm texture structure, and at the same time can also enhance certain properties of the synthetic leather, such as improving wear resistance. Laser engraving embossing has the characteristics of high precision and high flexibility, and can engrave complex patterns and textures on the surface of the synthetic leather according to design requirements to meet the needs of personalized customization. Through these embossing treatment methods, not only can the synthetic leather be given a beautiful appearance, but also by adding corresponding functional additives, it can have multiple functions such as antibacterial, mildew-proof, and flame-retardant, expanding the application field of the synthetic leather and increasing the added value of the product.

[0040] Advantages of the present invention

[0041] 1. Excellent environmental protection and recyclability

[0042] In the present invention, SEBS substrate is used to replace the traditional PVC / PU system. The main chain of SEBS is composed of ethylene-butene flexible segments (EB) and terminal polystyrene (PS) hard segments. There are no halogen atoms in the whole molecular structure, and no halogen-containing harmful substances will be released during the production, use and recycling processes. At the same time, there are no harmful solvent molecules in its molecules, avoiding the environmental pollution problems caused by solvent volatilization. The casting process directly coats SEBS onto the base fabric, abandoning the use of adhesives. When traditional adhesives are cured, intermolecular cross-linking reactions will produce emissions of volatile organic compounds (VOCs), while this invention avoids this process and eliminates the generation of VOCs from the source. In terms of recycling, SEBS and the base fabric are physically combined. This combination method enables the separation of SEBS and the base fabric through simple melting treatment during recycling. When SEBS molecules are in a molten state, their segments can be rearranged to restore plasticity, so that they can be directly recycled. The recycling rate of the SEBS-based synthetic leather > 95%, greatly reducing the pressure of waste on the environment and promoting the development of the synthetic leather industry towards the direction of green circulation; 2. Breakthrough flexibility and genuine leather touch

[0043] In the present invention, the plasticizer and the SEBS flexible chain segments play a synergistic role. Taking common plasticizers such as white mineral oil and liquid paraffin as examples, the long-chain hydrocarbon groups in their molecules insert between the SEBS molecular chains by van der Waals forces, weakening the original intermolecular forces, increasing the intermolecular chain spacing, and significantly enhancing the mobility of the molecular chains; during the non-glue direct coating process of the casting process, SEBS molecules can spread and penetrate more freely on the surface of the base fabric to form a uniform coating; when the cooling roll controls the crystallinity at a low temperature, the lower temperature slows down the movement of the SEBS molecular chains, and the molecular chain segments are arranged orderly to form a crystalline region. However, due to the precise control of conditions such as the cooling rate, excessive crystallization will not occur, maintaining good flexibility while ensuring a certain strength; the synthetic leather prepared by the present invention exhibits excellent flexibility, with a radial elongation at break of 51%-72% and a weft elongation at break of 75%-98%. This excellent performance stems from the fine regulation of the SEBS molecular state throughout the process. In the granulation process, the precisely controlled temperature, pressure and other conditions enable the uniform distribution of the SEBS molecular chain segments during melting and curing, laying a foundation for high flexibility. In the casting process, SEBS is uniformly coated on the base fabric, and the molecules are orderly spread in the two-dimensional plane, reducing the internal stress concentration points. The process of controlling the crystallinity by the low-temperature curing of the cooling roll optimizes the microstructure of SEBS at the molecular level. The lower temperature slows down the movement of the SEBS molecular chains, and they are arranged orderly to form a crystalline region. The precise control of the cooling rate and time avoids excessive crystallization and retains a large number of amorphous regions. The molecular chains in these amorphous regions are relatively free. When the material is stretched by an external force, the molecular chains can adapt to the external force through conformational changes and slippage; the addition of the plasticizer further weakens the intermolecular forces between the SEBS molecular chains, making the molecular chains more likely to slide and stretch when stressed, further enhancing the flexibility of the material. Macroscopically, this flexibility reduces the surface hardness of the synthetic leather to Shore A 55-80, and the touch is close to that of genuine leather, greatly improving the product use experience;

[0044] 3. Enhanced interfacial bonding strength and durability

[0045] In the casting process, under high pressure, the molten SEBS molecules have high activity and fluidity, and the SEBS molecular chains can fully penetrate into the fiber gaps of the base fabric. From a microscopic perspective, complex physical entanglements are formed between the SEBS molecules and the base fabric fiber molecules. When cooling and solidifying, the mobility of the SEBS molecular chains decreases, and the molecular chains approach and fix each other, and this physical entanglement forms a mechanical anchoring effect, enabling the SEBS layer to be tightly combined with the base fabric. Subsequently, corona treatment further enhances the interfacial bonding force. During the corona treatment process, the plasma generated by high-voltage discharge acts on the surface molecules of SEBS. The high-energy particles in the plasma impact the SEBS molecules, causing the molecular chains to break and generate free radicals. These free radicals react with oxygen in the air to form oxygen-containing polar groups on the SEBS surface, such as hydroxyl groups (-OH), carbonyl groups (-C=O), etc. The introduction of these polar groups increases the polarity of the SEBS surface, resulting in stronger interactions between the polar groups on the SEBS surface and the base fabric fiber surface, including hydrogen bonds, electrostatic attraction, etc. Through the dual effects of the mechanical anchoring effect and corona treatment to increase surface polarity, the peel strength of the present invention is increased by more than 70% compared with the traditional adhesive process, and there is no delamination after 500,000 bending tests, significantly improving the durability of the synthetic leather;

[0046] 4. Controllable scratch and abrasion resistance

[0047] The present invention optimizes the filler system and uses a compound of calcium carbonate and polyolefin treated with a coupling agent. After the surface of calcium carbonate is treated with a coupling agent, the hydroxyl groups on its surface chemically react with the active groups in the coupling agent molecules to form chemical bond connections. Taking a silane coupling agent as an example, the silanol groups (-SiOH) formed after its hydrolysis react with the hydroxyl groups on the calcium carbonate surface and dehydrate to form stable silicon-oxygen bonds (-Si-O-Ca). The organic groups at the other end of the coupling agent interact with the polyolefin molecules, enabling calcium carbonate and polyolefin to be tightly combined to form a stable composite system. In this composite system, calcium carbonate is uniformly dispersed in the SEBS matrix as rigid particles, forming a hard-phase dispersion structure. When the surface of the synthetic leather encounters scratching or abrasion, the calcium carbonate particles can effectively disperse stress and resist the damage of external forces to the material surface. At the same time, surface rolling of wear-resistant additives combined with corona pretreatment further improves the scratch and abrasion resistance. Corona pretreatment increases surface polarity and roughness, facilitating the adhesion of wear-resistant additives. The wear-resistant additive molecules are combined with the SEBS molecules through chemical bonds or strong physical adsorption to form a wear-resistant protective layer on the surface. These synergistic effects make the coating adhesion reach the 5B grade of the ISO11644 standard. The SEBS-based synthetic leather has a weight loss of less than 50 mg / 1000 times in the Taber abrasion test (CS-10 wheel, 1 kg load), and the scratch resistance grade reaches 5H (pencil hardness method). 5. Process stability and cost advantages

[0048] The granulation process controls the particle size within 1-3 mm. From the perspective of molecular dynamics, such a particle size range enables the SEBS particles to have relatively stable intermolecular interactions and uniform melt fluidity during the casting process. In the casting machine, SEBS particles of the same particle size can move at similar speeds and in similar ways, ensuring the stability of the coating process and enabling it to be compatible with different types of base fabrics, whether they are polyester fabrics, non-woven fabrics, cotton fabrics, nylon fabrics, etc., and good coating effects can be achieved. The dynamic vulcanization in the prior art is cancelled, avoiding the process control problems caused by the sensitivity of the vulcanization system. During the dynamic vulcanization process, the dosages of crosslinking agents such as sulfur and phenolic resin need to be precisely controlled. Excessive amounts will lead to excessive crosslinking of molecular chains and non-linear attenuation of mechanical properties. However, the present invention optimizes the process and adopts processes such as granulation and casting, improving the process tolerance rate. At the molecular level, stable process conditions enable the arrangement and interaction modes of SEBS molecules to remain consistent in each batch of products, so that the fluctuation of the elastic modulus between batches of SEBS-based synthetic leather is <5%, ensuring the stability of product quality. At the same time, the energy consumption of the equipment is reduced by 30% because the high-temperature and high-shear conditions required for dynamic vulcanization are avoided, reducing energy consumption. While reducing production costs, it also reduces pollutant emissions during the energy production process, achieving the unity of economic benefits and environmental benefits. Brief Description of the Drawings Detailed Description of the Embodiments

[0049] To better explain the present invention, the exemplary embodiments of the present invention will be described in more detail below. Although the exemplary embodiments of the present invention are shown below, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to enable a clearer and more thorough understanding of the present invention and to be able to convey the scope of the present invention completely to those skilled in the art.

[0050] Example 1

[0051] Preparation of SEBS-based Synthetic Leather 1

[0052] Step 1: Granulation of SEBS Mixture

[0053] Mix 35 parts of SEBS, 35 parts of white mineral oil, 26 parts of filler, 2 parts of bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate, and 2 parts of colorant at 80 °C to obtain a mixture. Heat the mixture to melt at 150 °C by a granulator with an operating pressure of 3 MPa, and then extrude the granules through the nozzle of the granulator. Cool and solidify the granular material with water at 19 °C for 3 minutes to obtain SEBS granules after granulation. The diameter of the SEBS granules after granulation is 3 mm. Then dry the SEBS granules after granulation in a dryer at 50 °C to ensure no moisture. Among them, the filler is a mixture obtained by a compounding process of calcium carbonate and polyethylene. The compounding process uses the coupling agent coating method for calcium carbonate, and the coupling agent is a silane coupling agent. The mass ratio of calcium carbonate to polyethylene is 20:60.

[0054] Step 2: Coat the SEBS granules after granulation onto a fabric substrate by a casting process.

[0055] Add the SEBS granules after granulation in Step 1 into a casting machine and heat to the molten state at 150 °C. Cast into a 20-μm-thick film through the die head of the casting machine with an operating pressure of 3 MPa and a speed of 15 m / min, and coat it on the surface of the fabric substrate of polyester cloth to obtain a fabric substrate coated with SEBS.

[0056] Step 3: Cool and solidify.

[0057] Cool and solidify the fabric substrate coated with SEBS through a cooling roller at 20 °C with a speed of 15 m / min to obtain a primary synthetic leather product based on SEBS.

[0058] Step 4: Perform corona treatment, shaping, and surface treatment.

[0059] First, conduct corona treatment on the surface of the primary synthetic leather product based on SEBS with a corona machine with an input power of 6 kW for 5 times, with each corona treatment time of 10 s. Keep the tension value of the constant traction force at 10 N / m, adjust the distance between the discharge electrode and the surface of the primary synthetic leather product based on SEBS to 2.5 mm, the treatment speed is 15 m / min, and the discharge intensity is 150 W·min / m. 2 ; Then coat the wear-resistant skin-friendly leather surface treatment agent and additives on the surface of the primary synthetic leather product based on SEBS by roll coating, and then dry the primary synthetic leather product based on SEBS in an oven at 120 °C with a speed of 15 m / min for 180 s to obtain the SEBS synthetic leather after shaping and surface treatment.

[0060] Step 5: Embossing treatment and cutting.

[0061] The SEBS synthetic leather after forming and surface treatment described in Step 4 is cooled naturally at 15°C to achieve wear resistance, skin-friendly appearance and functional effects, and then subjected to embossing treatment by a vacuum embossing machine to obtain patterned SEBS synthetic leather, which is cut and trimmed as required to obtain the finished SEBS-based synthetic leather product.

[0062] Example 2

[0063] Preparation of SEBS-based synthetic leather 2

[0064] Step 1: Granulation of SEBS mixture

[0065] Mix 28 parts of SEBS, 28 parts of white mineral oil, 40 parts of filler, 2 parts of bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate, and 2 parts of colorant at 80°C to obtain a mixture. Heat the mixture to melt at 170°C by a granulator, the operating pressure of the granulator is 5 MPa, and then extrude the particles through the nozzle of the granulator. Cool and solidify the granular material with water at 19°C to obtain granulated SEBS particles, the cooling time is 3 minutes, the diameter of the granulated SEBS particles is 3 mm, and then dry the granulated SEBS particles in a dryer at 50°C to ensure no moisture; wherein, the filler is a mixture obtained by a compounding process of calcium carbonate and polypropylene, the compounding process uses a coupling agent coating method for calcium carbonate, the coupling agent is a silane coupling agent, and the mass ratio of calcium carbonate to polyethylene is 20:60;

[0066] Step 2: Coating the granulated SEBS particles onto the fabric substrate by a casting process

[0067] Add the granulated SEBS particles described in Step 1 into a casting machine and heat to a molten state at 170°C. Cast a 20-μm-thick film through the die head of the casting machine with an operating pressure of 5 MPa and a speed of 15 m / min, and coat it onto the surface of the fabric substrate of polyester cloth to obtain a fabric substrate coated with SEBS.

[0068] Step 3: Cooling and solidification

[0069] Cool and solidify the fabric substrate coated with SEBS by a cooling roller at 20°C with a speed of 15 m / min to obtain a primary finished product of SEBS-based synthetic leather.

[0070] Step 4: Corona treatment, forming and surface treatment

[0071] First, corona treatment is carried out 5 times on the surface of the primary SEBS-based synthetic leather product with a corona machine with an input power of 6 kW. The corona time for each treatment is 10 s, the tension value maintaining a constant traction force is 10 N / m, the distance between the discharge electrode and the surface of the primary SEBS-based synthetic leather product is adjusted to 2.5 mm, the treatment speed is 15 m / min, and the discharge intensity is 150 W·min / m 2 ; Then, the wear-resistant skin-friendly leather surface treatment agent and additives are coated on the surface of the primary SEBS-based synthetic leather product by roll coating. Then, the primary SEBS-based synthetic leather product is dried in an oven at 130 °C with a speed of 15 m / min for 180 s to obtain the SEBS synthetic leather after forming and surface treatment;

[0072] Step 5, embossing treatment and cutting

[0073] The SEBS synthetic leather after forming and surface treatment in Step 4 is cooled naturally at 15 °C to achieve the wear-resistant and skin-friendly appearance and functional effects. Then, embossing treatment is carried out by a vacuum embossing machine to obtain the patterned SEBS synthetic leather, which is cut and trimmed as needed to obtain the finished SEBS-based synthetic leather product.

[0074] Example 3

[0075] Preparation of SEBS-based synthetic leather 3

[0076] Step 1, granulation of SEBS mixture

[0077] 40 parts of SEBS, 40 parts of white mineral oil, 16 parts of filler, 2 parts of bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate, and 2 parts of colorant are mixed evenly at 80 °C to obtain a mixture. The mixture is heated and melted at 140 °C by a granulator, the operating pressure of the granulator is 4 MPa, and then the particles are extruded through the nozzle of the granulator. The granular material is cooled and solidified by water at a temperature of 19 °C to obtain the granulated SEBS particles. The cooling time is 3 min, the diameter of the granulated SEBS particles is 3 mm, and then the granulated SEBS particles are dried in a dryer at 50 °C to ensure no moisture; among them, the filler is a mixture obtained by a compounding process of calcium carbonate, polyethylene, and polypropylene. The compounding process uses the method of coupling agent coating on calcium carbonate, the coupling agent is a silane coupling agent, and the mass ratio of calcium carbonate, polyethylene, and polypropylene is 20:30:30;

[0078] Step 2, coating the granulated SEBS particles onto the fabric substrate by a casting process

[0079] Add the granulated SEBS particles described in Step 1 to a casting machine and heat them to a molten state at a temperature of 145°C. Cast them into a 20-μm-thick film through a die head of a casting machine with an operating pressure of 4 MPa and a speed of 15 m / min, and coat it on the surface of the fabric substrate of a polyester cloth to obtain a fabric substrate coated with SEBS;

[0080] Step 3, Cooling and curing

[0081] Cool and cure the fabric substrate coated with SEBS through a cooling roller at 20°C at a speed of 15 m / min to obtain a primary finished product of SEBS-based synthetic leather;

[0082] Step 4, Corona treatment, forming and surface treatment

[0083] First, level the surface of the primary finished product of SEBS-based synthetic leather and introduce it into a corona machine with a power of 6 kW for corona treatment 5 times. Each corona treatment time is 10 s. Keep the tension value of the constant traction force at 10 N / m. Adjust the distance between the discharge electrode and the surface of the primary finished product of SEBS-based synthetic leather to 2.5 mm. The treatment speed is 15 m / min, and the discharge intensity is 150 W·min / m 2 ; Then, coat the wear-resistant skin-friendly leather surface treatment agent and additives on the surface of the primary finished product of SEBS-based synthetic leather by roll coating. Then, dry the primary finished product of SEBS-based synthetic leather in an oven at 120°C at a speed of 15 m / min for 180 s to obtain the SEBS synthetic leather after forming and surface treatment;

[0084] Step 5, Embossing treatment and cutting

[0085] Cool the SEBS synthetic leather after forming and surface treatment described in Step 4 naturally at 15°C to achieve the appearance and functional effects of wear resistance and skin feel. Then, perform embossing treatment through a vacuum embossing machine to obtain the patterned SEBS synthetic leather and cut and trim it as needed to obtain the finished product of SEBS-based synthetic leather.

[0086] Example 4

[0087] Prepare SEBS-based synthetic leather 4

[0088] Step 1, Granulation of SEBS mixture

[0089] Mix 30 parts of SEBS, 32 parts of liquid paraffin, 34 parts of filler, 1.5 parts of antioxidant H3302 for nylon polymerization, and 2.5 parts of colorant at 70 °C to obtain a mixture. Heat the mixture to melt at 160 °C through a granulator with an operating pressure of 4 MPa, then extrude the particles through a nozzle. Cool and solidify the granular material with water at 25 °C for 2.5 min. The diameter of the granulated SEBS particles is 2 mm, and then dry the particles in a dryer at 45 °C to ensure no moisture. Among them, the filler is a mixture obtained by a compounding process of calcium carbonate and polypropylene. The compounding process uses the coupling agent coating method for calcium carbonate, the coupling agent is a titanate coupling agent, and the mass ratio of calcium carbonate to polypropylene is 20:60. Step 2: Coat the granulated SEBS particles onto a fabric substrate by a casting process.

[0090] Add the granulated SEBS particles described in Step 1 into a casting machine and heat to a molten state at 160 °C. Cast into a 30-μm-thick film through a casting die of the casting machine with an operating pressure of 4 MPa and a speed of 18 m / min, and coat it onto the surface of a non-woven fabric substrate to obtain a fabric substrate coated with SEBS.

[0091] Step 3: Cooling and solidification

[0092] Cool and solidify the fabric substrate coated with SEBS through a cooling roller at 25 °C with a speed of 18 m / min to obtain a primary synthetic leather product based on SEBS.

[0093] Step 4: Corona treatment, shaping, and surface treatment

[0094] First, level the surface of the primary synthetic leather product based on SEBS and introduce it into a corona machine with a power of 8 kW for corona treatment 4 times. Each corona treatment time is 12 s, maintain a constant traction tension value of 12 N / m, adjust the distance between the discharge electrode and the surface of the primary synthetic leather product based on SEBS to 2 mm, the treatment speed is 18 m / min, and the discharge intensity is 120 W·min / m. 2 ; Then, coat a leather surface treatment agent and additives with waterproof and wear-resistant effects on the surface of the primary synthetic leather product by roll coating, and then pass it through an oven at 130 °C and dry it at a speed of 18 m / min for 200 s to obtain the SEBS synthetic leather after completion of shaping and surface treatment.

[0095] Step 5: Embossing treatment and cutting

[0096] The SEBS synthetic leather after forming and surface treatment described in Step 4 is cooled naturally at 18°C to achieve the appearance and functional effects of waterproofing and wear resistance; then it is subjected to embossing treatment by a hot press embossing machine to obtain the patterned SEBS synthetic leather, which is cut and trimmed as needed to obtain the finished SEBS-based synthetic leather product.

[0097] Example 5

[0098] Prepare SEBS-based synthetic leather 5

[0099] Step 1: Granulation of SEBS mixture

[0100] Take 32 parts of SEBS, 30 parts of mineral oil, 34 parts of filler, 2 parts of light and oxygen stabilizer P-334, and 2 parts of colorant, mix them evenly at 75°C to obtain a mixture, heat the mixture to melt at 155°C in a granulator, the operating pressure of the granulator is 3.5 MPa, and extrude the particles through a nozzle; the granular material is cooled and solidified by air at a temperature of 22°C, the cooling time is 4 min, the diameter of the granulated SEBS particles is 2.5 mm, and then it is dried at 48°C in a dryer to ensure no residual moisture; the filler is obtained by compounding calcium carbonate with polyethylene and polypropylene, and calcium carbonate is coated with a silane coupling agent during compounding, and the mass ratio of calcium carbonate, polyethylene, and polypropylene is 20:40:20;

[0101] Step 2: Coating the granulated SEBS particles obtained in Step 1 onto a fabric substrate by a casting process

[0102] Add the granulated SEBS particles obtained in Step 1 into a casting machine and heat them to a molten state at a temperature of 155°C, and cast them into a 25-μm-thick film through the die head of a casting machine with an operating pressure of 3.5 MPa and a speed of 16 m / min, and coat it onto a nylon fabric substrate to obtain a fabric substrate coated with SEBS;

[0103] Step 3: Cooling and solidification

[0104] The fabric substrate coated with SEBS is cooled and solidified by a cooling roller at 22°C with a speed of 16 m / min to obtain a primary finished SEBS-based synthetic leather;

[0105] Step 4: Corona treatment, forming and surface treatment

[0106] First, the surface of the primary finished SEBS-based synthetic leather is smoothly introduced into a corona machine with a power of 7 kW for corona treatment 4 times, each corona treatment time is 13 s, the tension value of the constant traction force is 11 N / m, adjust the distance between the discharge electrode and the surface of the primary finished SEBS-based synthetic leather to 2.2 mm, the treatment speed is 16 m / min, and the discharge intensity is 130 W·min / m 2; Then, the soft and antifouling leather surface treatment agent and auxiliary agent are applied to the surface of the primary finished synthetic leather product by spraying, and then placed in a 125°C oven and dried at a speed of 16m / min for 190s to obtain a SEBS synthetic leather after molding and surface treatment;

[0107] Step 5: Texture processing and cutting

[0108] The SEBS synthetic leather after forming and surface treatment in step 4 is naturally cooled at 20° C. to achieve a soft, anti-fouling appearance and functional effects; then, it is subjected to a pattern absorption treatment by a roller-pressing pattern absorption machine to obtain a patterned SEBS synthetic leather, which is cut and trimmed as needed to obtain a finished SEBS-based synthetic leather product.

[0109] Comparative Example 1

[0110] PVC synthetic leather (polyvinyl chloride synthetic leather; Zhejiang Huafeng Synthetic Leather Co., Ltd.; product model: HF-PVC-001);

[0111] Comparative Example 2

[0112] PU synthetic leather (polyurethane synthetic leather; Wenzhou Artificial Leather Co., Ltd.; product model: WZ-PU-2024);

[0113] Comparative Example 3

[0114] Traditional process SEBS synthetic leather (styrene-ethylene-butylene-styrene block copolymer synthetic leather; Jiangsu Shuangxiang Group Co., Ltd.; product model: SX-SEBS-09).

[0115] Table 1. Performance parameters

[0116]

[0117] From the data in Table 1, it can be seen that Examples 1-5 performed well in multiple key performance indicators:

[0118] Excellent flexibility: The elongation at break of the synthetic leather of Examples 1-5 is 51%-72% in the radial direction and 75%-98% in the weft direction, far exceeding that of Comparative Examples 1-3. From the perspective of molecular structure, the ethylene-butylene flexible chain segment of the SEBS main chain gives the material good elastic deformation ability, and its carbon-carbon single bond can rotate freely. When subjected to force, the molecular chain can be greatly stretched and bent. The long-chain hydrocarbon groups of the plasticizer molecules (such as white mineral oil, liquid paraffin, etc.) and the SEBS molecular chains act through van der Waals forces to increase the molecular chain spacing, weaken the interaction force, and enhance the activity of the molecular chains. During the casting and cooling and solidification process, the SEBS molecules are evenly spread on the base fabric and the crystallinity is precisely controlled, retaining a large number of amorphous areas, so that the molecular chains can adapt to external forces through conformational changes and slippage when subjected to force, ultimately achieving a high elongation at break and bringing a soft touch close to that of genuine leather.

[0119] High interfacial bonding strength and durability: The peel strength of Examples 1-5 of the present invention is between 50-64 N, which is much higher than that of Comparative Examples 1-3. In the casting process, under the action of pressure, the molecular chains of molten SEBS fully penetrate into the gaps between the base fabric fibers and form a mechanical anchoring effect after cooling and solidification; corona treatment generates free radicals on the surface of SEBS, which react with oxygen to form oxygen-containing polar groups, increasing the surface polarity and resulting in stronger interactions such as hydrogen bonds and electrostatic attractions between the surface polar groups of SEBS and the base fabric fibers; these dual effects significantly enhance the bonding force between the SEBS layer and the base fabric, and there is no delamination after 50,000 bending tests, greatly improving the durability of the synthetic leather;

[0120] Good scratch and abrasion resistance: The scratch resistance level of Examples 1-5 reaches 4-5 levels, and the Taber weight loss is less than 50 mg / 1000 times, which is better than that of Comparative Examples 1-3. The present invention optimizes the filler system. After being treated with a coupling agent, calcium carbonate is tightly combined with polyolefin to form a hard phase dispersion structure in the SEBS matrix; when the surface is scratched or worn, the calcium carbonate particles effectively disperse the stress; corona pretreatment increases the surface polarity and roughness, enabling better adhesion of the wear-resistant additives, and forming a wear-resistant protective layer with the SEBS molecules through chemical bonds or strong physical adsorption, thereby improving the scratch and abrasion resistance;

[0121] Stable product quality and cost advantages: The fluctuation of the elastic modulus between batches of Examples 1-5 is <5%, showing good product quality stability. The granulation process controls the particle size within 1-3 mm, making the intermolecular interactions of SEBS particles stable during the casting process, with uniform melt fluidity, ensuring the stability of the coating process and being compatible with different base fabrics; Canceling dynamic vulcanization avoids the sensitivity problem of the vulcanization system, improves the process tolerance rate, and makes the arrangement and interaction mode of SEBS molecules consistent in each batch of products; at the same time, avoiding the high temperature and high shear conditions required for dynamic vulcanization reduces the equipment energy consumption by 30%, reduces energy consumption and production costs, and realizes the unity of economic and environmental benefits;

[0122] Outstanding environmental protection performance: The synthetic leather of Examples 1-5 has no harmful substance release, and the recycling rate > 95%, while Comparative Examples 1-3 have varying degrees of environmental pollution problems; The molecular structure of SEBS does not contain halogen atoms and harmful solvent molecules. The casting process abandons the use of adhesives, avoiding VOC emissions; during recycling, SEBS and the base fabric are physically combined and can be separated by simple melting treatment. The SEBS molecular chain segments can be rearranged to restore plasticity and can be directly recycled, promoting the development of the synthetic leather industry towards the direction of green recycling.

[0123] The above are only the preferred embodiments of the present invention, and are not any other form of limitation to the present invention. Any modification or equivalent change made according to the technical essence of the present invention still belongs to the scope claimed by the present invention.

Claims

1. A synthetic leather based on SEBS, characterized in that, The SEBS-based synthetic leather is made by directly coating the granulated SEBS particles onto a fabric substrate using a casting process. The recycling rate of the SEBS-based synthetic leather is >95%, the radial elongation at break is 51%-72%, the weft elongation at break is 75%-98%, the peel strength is 50-64 N, the scratch resistance grade is 4-5, the Taber weight loss is <50 mg / 1000 cycles, the fluctuation of the elastic modulus between batches is <5%, the Shore A hardness is 55-80, and the touch is close to that of genuine leather.

2. The method for manufacturing synthetic leather based on SEBS according to claim 1, characterized in that, It includes the steps of: Step 1: Granulating the SEBS mixture to obtain granulated SEBS particles, where the molecular weight of the SEBS is 50,000-400,000; Step 2: Using a casting process to coat the granulated SEBS particles onto a fabric substrate to obtain a fabric substrate coated with SEBS; Step 3: Cooling and curing the fabric substrate coated with SEBS through a cooling roller to obtain a primary finished product of SEBS-based synthetic leather; Step 4: Performing shaping and surface treatment on the primary finished product of SEBS-based synthetic leather to obtain a SEBS synthetic leather after completing shaping and surface treatment; Step 5: Performing embossing treatment and cutting on the SEBS synthetic leather after completing shaping and surface treatment to obtain the finished product of SEBS-based synthetic leather.

3. The method for manufacturing synthetic leather based on SEBS according to claim 2, wherein In Step 1, the granulation of the SEBS mixture is to uniformly mix 10-40 parts of SEBS, 10-40 parts of plasticizer, 10-40 parts of filler, 0.2-3 parts of stabilizer, and 0.2-3 parts of colorant at 10-100 °C to obtain a mixture. The mixture is melted in a granulator at a temperature of 110-210 °C, and then extruded through the nozzle of the granulator to form granular materials with a particle size of 1-3 mm. The operating pressure of the granulator is 1-5 MPa. The granular materials are cooled and solidified through a cooling water tank or air cooling at a temperature of 10-60 °C for 1-3 min to obtain granulated SEBS particles, and then the granulated SEBS particles are dried.

4. The method for manufacturing synthetic leather based on SEBS according to claim 2, wherein In Step 2, the casting process is to add the granulated SEBS particles obtained in Step 1 into a casting machine and heat them to a molten state at a temperature of 130-230 °C. The molten SEBS is directly and uniformly coated onto a fabric substrate using the casting process of the casting machine to obtain a fabric substrate coated with SEBS. The operating pressure of the die head of the casting machine is 1-18 MPa, the speed is 3-30 m / min, and the coating thickness is controlled to be 20-60 μm to ensure uniform coating of the SEBS layer and consistent film thickness.

5. The method for manufacturing synthetic leather based on SEBS according to claim 2, characterized in that, In Step 3, the fabric substrate coated with SEBS is cooled and cured through a cooling roller to obtain a primary finished product of SEBS synthetic leather. The temperature of the cooling roller is 5-60 °C, and the speed is 3-25 m / min.

6. The method for manufacturing synthetic leather based on SEBS according to claim 2, wherein In step 4, first, the surface of the primary SEBS-based synthetic leather product is subjected to corona treatment 3 to 5 times using a corona machine with a power of 6 - 10 kW, and the corona time for each treatment is 5 - 15 s. Then, a synthetic leather surface treatment agent and additives are used to roll coat / spray coat the surface of the primary SEBS synthetic leather product, and then it is dried to obtain the SEBS synthetic leather after forming and surface treatment.

7. The method for manufacturing synthetic leather based on SEBS according to claim 2, characterized in that, In step 5, the formed and surface-treated SEBS synthetic leather is subjected to embossing treatment using a vacuum embossing machine to produce patterned SEBS synthetic leather, and it is cut and trimmed as required to obtain the SEBS-based synthetic leather product.

8. The method for manufacturing synthetic leather based on SEBS according to claim 2, characterized in that, The granulated SEBS is heated and circulated for drying in an oven at 30 - 50 °C for 50 - 600 s.

9. The method for manufacturing synthetic leather based on SEBS according to claim 2, characterized in that, The filler is a mixture obtained by compounding calcium carbonate and polyolefin.

10. The method for manufacturing synthetic leather based on SEBS according to claim 6, wherein the corona treatment is to smoothly introduce the primary finished product of the synthetic leather based on SEBS into a corona machine, the tension value of the constant traction force is 10 - 20 N / m, the distance between the discharge electrode and the surface of the SEBS synthetic leather is adjusted to 1 - 2.5 mm, the treatment speed is 8 - 20 m / min, and the discharge intensity is 50 - 150 W·min / m 2 .

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