2results about How to "Increase shrinkage temperature" patented technology

This invention discloses a pH-responsive MOF nanocomposite chromium-free tanning agent, its preparation method, and its application, belonging to the technical field of chromium-free tanning agents for leather. The method disclosed in this invention involves forming a ligand with a borate ester module through the dehydration condensation of 4-carboxyphenylboronic acid and tartaric acid, and then binding zirconium to the ligand via a solvothermal method to form a MOF tanning agent. Subsequently, zirconium tartrate is loaded onto the MOF, enabling controlled release of zirconium tartrate through a pH-responsive switch in the ligand. This improves the problem of uneven tanning caused by the rapid and strong binding of zirconium ions to collagen fibers, resulting in tanned leather with a shrinkage temperature exceeding 80 °C, thereby effectively improving the quality of zirconium-tanned leather products.

This invention relates to a chromium-free tanning agent based on hydrogen bond reinforcement and its preparation method. The invention first prepares single-terminated and double-terminated -NCO ureapyrimidine ketone compounds, then reacts these compounds with an aqueous solution of bisulfite to prepare a water-soluble reactive ureapyrimidine ketone-based chromium-free non-metallic tanning agent. Compared with conventional organic synthetic tanning agents, the chromium-free tanning agent developed in this invention can both covalently bind with skin collagen and further form a quadruple hydrogen-bonded dimer in the leather fiber network through the hydrogen bond recognition effect of ureapyrimidine ketones (Upy). This strong hydrogen bonding between tanning agent molecules strengthens the molecular cross-linking network structure of the tanned leather, resulting in higher shrinkage temperature and mechanical strength. In particular, the tanning agent developed in this invention contains two types of tannin molecules of different sizes, exhibiting excellent selective filling effect. The tanned leather is full and uniform, with good softness, and can be used in the production of light-colored lightweight leather.