Triethoxysilane End-Functional Branched Waterborne Polyurethane Adhesives for Leather Substrates
Longfang Ren, Sijie Yu, Qiaoxuan Niu, Taotao Qiang
Abstract
In order to improve the adhesion and water resistance of waterborne polyurethane (WPU) adhesive, a kind of amino-terminated hyperbranched organosilicon (HPSi-NH 2 ) was first synthesized by using trimethylchlorosilane, diethoxydimethylsilane, and γ-aminopropyltriethoxysilane (KH550) as raw materials. Then, HPSi-NH 2, as the cross-linking agent, was used to modify the polyurethane prepolymer to obtain HPSi-NH 2 -modified WPU (HSiPU). The single-factor experiment results showed that when the amount of HPSi-NH 2 was 2.0 wt %, the adhesion properties of HSiPU-2 were the best. Compared with the HSiPU-0 film, the water absorption rate of the HSiPU-2 film decreased by 10.9%, the water contact angle increased by 26.3°, the tensile strength increased by 10.1 MPa, and the elongation at break increased from 630.7 to 813.0%. HSiPU adhesive was used in the bonding of the goat leather substrate, and the results showed that the peel strength of leather bonded by HSiPU-2 was increased from 1.38 to 3.15 N/mm, and the maximum peel force was increased from 1.67 to 5.51 N/mm, which indicated that the bond strength of HSiPU adhesive with different contents of HPSi-NH 2 can be used for bonding substrates with different cohesion strengths.