Wear resistance is an important logistics index to evaluate the durability of PU leather for upper. Some researchers have prepared a high elastic waterborne polyurethane, which meets the requirements of wear resistance of leather / synthetic leather coating. The silane coupling agent was used as the post chain extender and crosslinking agent, which could obviously improve the mechanical strength, elongation and resilience of the polyurethane film. The enrichment of siloxane on the polyurethane surface could effectively reduce the friction resistance of the coating, and then improve the wear resistance of the waterborne polyurethane coating. Environmental friendly solvent-free polyurethane synthetic leather was prepared by organosilicon modified solvent-free two-component polyurethane. The results showed that the introduction of organosilicon reduced the surface energy of polyurethane, reduced the surface dryness and improved the wear resistance; In addition, the low-temperature folding fastness and peel strength were also improved, so that the environmental friendly solvent-free polyurethane synthetic leather can meet the comprehensive performance requirements of synthetic leather for sports shoes. Other researchers have prepared high solid content waterborne polyurethane with multi-component particle size distribution and used it as the coating of microfiber synthetic leather. The research results show that the high solid content is conducive to improving the mechanical properties, wear resistance, water resistance, etc. of the coating, improving the high solid content of the surface waterborne polyurethane coating materials, and greatly improving the durability of the microfiber synthetic leather.
The researchers added hemp rod powder to polyurethane coating adhesive and coated it on the surface of fabric by direct scraping to prepare a lightweight and comfortable upper material with high comprehensive performance. It has the properties of air permeability and comfort, waterproof and brushing resistance, antibacterial and high strength, and meets the requirements of waterproof, moisture permeability, antibacterial and reinforcing properties of shoe materials and practical requirements of light and comfortable. It is found that adding graphene can improve the mechanical and electrical properties of waterborne polyurethane and improve the wear resistance of the coating. Graphene has a special monolayer and two-dimensional nanoscale structure; High hardness, transparency, conductivity, heat conduction and other special properties are used in the manufacture of leather and synthetic leather. It is expected to give leather and leather special high physical and functional properties such as abrasion resistance, scratch resistance, antistatic, conductive heat conduction, antibacterial and mildew resistance, UV aging resistance, flame retardant and smoke suppression, electromagnetic shielding, and comprehensively improve the grade of leather and synthetic leather. Nano materials have special properties such as surface effect, small size effect, optical effect, quantum size effect, macro quantum size effect, etc., and present characteristics that conventional materials do not have. Nano coating technology has high scientific and technological content, and the coating is non-toxic and harmless. With the help of traditional coating technology and the addition of nano materials, the function of traditional coatings can be improved by leaps and bounds. The hardness and wear resistance of the coating can be further improved by adding nano materials to the hardness and wear resistance of the coating and maintaining high toughness, thus improving the wear resistance of the shoe material. Traditional coating systems often encounter the problem of poor adhesion of the coating, while the leather coated with nano titanium oxide shows better adhesion performance, which increases the molecular cross-linking between the leather surface and the coating. The multi-faceted properties required by shoe leather are not single and independent. So many performance requirements are concentrated on synthetic leather, which is extremely technically challenging. In the application, the necessary choice and balance can be made according to the needs of the specific wearing environment.