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In recent years, with the strengt§σλhening of environmental protecti↑©←≥on awareness and measures, thδ₩וe research and development₹$$∞ of water-based polyurethane leather fini₹←↓shing agent has been highly vaε ↑₹lued, and the performance of cationic water-∑♣φ♦based polyurethane finishing agent hφ∏ ₹as been widely studied at hom↑•≈e and abroad.

This paper introduces the cationic water-&™♦based polyurethane bottom coating₩λ agent, with a fixed fillin®φg performance, back cover, ca±♠×✔n be and negatively charge☆Ω∞d leather blank to produce better ≠ ' adhesion, but also w≠εith the anion top coating agent fr£↕om a strong coupling effect, so that the tanningα× feel softer, fuller, and≠γ further improve the quality of leather. M↔✔₽ odified acrylic leather finis←πhing agent acrylic resin is a kind of l↓<♠eather finishing agen≥ t material widely used"σ∑ in the world, with an≠γnual output accounting for about 70β∑'γ% of leather finishing agen≤ σt. From the aspects of production cost, tech •↕≈nological process and comprehensive performanc♠ e, acrylic resin as a finishing materia↓"l has many advantages over othe↕'r chemical materials, b•β∑δut there is nothing in the world. Its d'₹efect is thermal adhesion and cold brittleness,£∞®α which limits its use by climati₩✘c conditions. Since 198• 7, Rohm and Hass companies in the Un✘σ"ited States have developed new prod→∑≈₩ucts, the second generation acry®$÷lic resin (sGA), which has made a b₽≤™reakthrough in hot stick©&♠↓y cold brittle. Subsequenπ♣>→tly, China has also achieved results in the modi&✔fication of acrylic materials. However, most∏↕ of its development methods Ω§are the introduction of functional monom‌★ers and acrylic monomers for multiple copolymer≤↓↓ization, graft copolymβλπerization, or external ≤★δ∞crosslinking agent, so that thα☆‌←e linear structure becomes a network strφφΩucture, thereby improving the heat and cold resi♣$✘¥stance of the coating film. ±×₩♥The technical means used stay at the level of ‌'<✘molecular structure. Although the thermal₹× adhesion and cold brittle pe★¥£←rformance has been improved, i★πσt is still insufficient. Suγφ≈ch finishing agents in the ™€ northern region is stiσσ™&ll not effective use. The main compα™↔≠onent of the protein adhesive is c•₩≥♥asein. Because the original casein (protε≥∏ein) is easy to deterior₹∞ ate, the protein adhesive used now  ☆​™is modified. The coating ©≥ ∏is soft and natural, with strong bonding for ↕§δce, high temperature resistant ironing, firmly c↓©ombined with the leather surface, and ha∑↔∞s clear natural grain patterns of le↔•δather. It can maintain good water¶> vapor permeability and other sanitary properti ¥≠£es of the leather. Nitrocelluγ©lose is mainly used as a brightener for¥✘&✔ leather top layer, and the vast∏₽♦ majority of nitrocellulose, namely nitr∏∏↑ocellulose (NC), is bright, beau¥≈§tiful, acid-resistant, oil-resistant¶λ₽≥, water-resistant and dry-wet-rub-res‌λ↔istant. It can be divided into high-gloss, d<ε ark-light, silk-like, wax-like, co$$♣lorless, transparent, etc. The main feat> ₹↑ure is that the coating is brittle, no agin☆✔↔ g resistance, poor cold resistance and poor air ♠•permeability after film€φ★ formation.