High Elongation Rate Leather Finishing Agents

Garment leather with high elasticity is a kind of new product in the market. It has some excellent properties, such as high elongation ratio and fold-fastness. Great contribution has been done to the rank of domestic leather products by the garment leather with high elasticity. However, big challenges are faced the finishing agents, which are the magic agents to make leathers with good appearance. High elongation of finishing agents is one of these challenges. High elongation of finishing agents may prevent the coating from rupture when leather products are folded.Finishing agent with high elongation should have following properties: climate-resistance, high elongation, flexibility, dry and wet erase-resistance. Polyurethane is designed as basic resin and improved from its basic properties to satisfy command from new leather products.Three parts of this experiment were designed, which include using n-butylamine as chain-extension agent, using hydroxyl-terminated polydimethylsiloxane (OH-terminated PDMS) as chain-extension agent and using PPG and PTMG as mixed raw material for synthesis. It may be the first time of using n-butylamine and OH-terminated PDMS as chain-extension agents.As a result, n-butylamine as chain-extension agent decreases the inter action of molecular and increases the elongation of PU to 1400%. The method of using OH-terminated PDMS as chain-extension agent decreases the water absorption of the PU films, compared with the traditional method of adding OH-terminated PDMS in the system with poly binary alcohol. The water absorption of the PU films synthesized by this method was as 1/4 as those from traditional method. The result of using mixed poly binary alcohol as raw material is also discussed. It is shown that the elongation may reach 1496% when the mol ratio of PPG/PTMG was 0.3, while the elongation is always low when mol ratio of PPG/PTMG changes.Glass transition temperature (Tg) is obtained by differential scanning calorimetry (DSC). The result showed that the Tg of the products is always about -80 ℃. So the low temperature resistance of the films is ensured. At last, a finishing practice is...