EVA Equivalent Polyurethane Slipper and Sneaker Systems

EVA Equivalent Polyurethane Slipper and Sneaker Systems Footwear users prioritize comfort and durability, and when choosing, they make their selections based on shoes that provide these features. Shoe sole manufacturers are equally aware of this concept. Flokser Kimya's EVA equivalent slippers and sole systems aim to address sector needs by combining these properties. Slipper and sneaker products manufactured with EVA (ethylene vinyl acetate) offer users comfort through their lightness and soft structure. However, EVA cannot be used independently due to poor mechanical performance and short product lifespan. This limitation has led manufacturers to hard polyurethane systems with high density and superior mechanical properties, which cannot achieve the desired comfort level provided by EVA. Current sector applications represent two extremes in the basic properties offered by these two different raw materials. The soft slipper systems from Flokser Kimya, which shaped this product category in the past, were highly valued by users and generated new demands. To address this dilemma, Flokser Kimya's R&D center developed a solution that combines the extreme properties of EVA and polyurethane within a single polyurethane system and brought it to market. No comparable polyurethane currently exists in the industry. EVA equivalent polyurethane systems have been developed for both slipper and sneaker applications. Standard polyurethane systems used in slipper production have a density of 250-300 kg/m³ with hardness between 45-60 ShoreA. EVA equivalent slipper systems, by contrast, enable production of soft slippers with 20-25 ShoreA hardness at the same density, delivering comfort and convenience instead of the 45-55 ShoreA hardness of standard slipper products. Due to this hardness level and superior in-mold flowability compared to standard slippers, the system also permits production of closed slippers that do not require mattresses and uppers. For designs requiring insole application, it is preferred over polyether polyol-based insole applications for its softness. [caption id="attachment_134121" align="aligncenter"] Figure 1. Textile-free PU slippers.[/caption] Standard polyurethane systems used in sneaker production have a density of 350-450 kg/m³ with hardness between 40-50 ShoreA. In flex testing, which measures product durability under use conditions, results range from 80,000 to 100,000 steps at -5°C. The developed EVA equivalent sneaker product achieves comparable hardness at 280-350 kg/m³ density. This EVA equivalent polyurethane sole product provides approximately 25% weight advantage. Compression set testing, per ASTM D395 standard, measures the shape recovery capability of shoe soles under load. For compression set, EVA shoe soles recover 10% of their original shape, while our developed H-510 and H-466 products recover approximately 74% of their original shape after loading. Additionally, it does not require secondary materials as EVA does, providing operational advantages. Our EVA equivalent polyurethane product also delivers superior abrasion resistance, with 25% less relative volume loss in abrasion testing compared to EVA. EVA equivalent polyurethane slipper and sneaker systems harmonize cost effectiveness and comfort with every step of daily life. [caption id="attachment_134123" align="aligncenter"] Figure 3. Low density sneaker.[/caption] A comparison of our EVA equivalent polyurethane system with standard slipper and sole properties is presented in Table 1. * Reaction and working conditions were obtained from measurements conducted with a low-pressure casting machine operating at 6000 rpm. ** Per TS EN 12222 standard, test results of samples were taken after conditioning at 23±2°C and 50% relative humidity for 24 hours. Dr. Serpil Yılmaztürk Güney P&D Manager Flokser Kimya Kerim Can Ünlü P&D Executive Flokser Kimya Tibet Hüten P&D Researcher Flokser Kimya