Short-Branched Fluorinated Polyurethane Coating Exhibiting Good Comprehensive Performance and Potential UV Degradation in Leather Waterproofing Modification

Shouhua Su,Juan Wang,Jinfeng Yuan,Zhicheng Pan,Chao Li,Mingwang Pan

doi:10.3390/coatings11040395

Abstract

In the current leather market, waterproof leather occupies a large proportion, where waterproofness has become one of the important standards for leather selection. However, the most advanced fluorine-containing waterproofing agents on the market always have long chains of over eight carbons (C8), whose use has been restricted due to their bioaccumulation and recalcitrance in natural environment. Consequently, creating waterproof materials characterized by their environmentally friendly qualities and high performance is of great significance. Herein, we report a novel strategy for preparation of the fluorinated polyurethanes containing short branched fluorocarbon chains, and apply it in leather waterproofing. Because the fluorine-containing chain segments are enriched on the coating surface, the waterproof agent coating shows good hydrophobicity, low water absorption, high wear resistance and potential photodegradation of performances. Additionally, the water and oil proof performances of the coating are comparable to that of the marketed C8 waterproofing agent. Its solvent-resistant and antifouling performances are also outstanding. Therefore, the coating can meet the property requirements for daily use and has broad application prospects.

Highlights

At present, leather has a wide range of applications, but its development is limited by its easy aging and poor properties in terms of water proofing and scratch resistance.The main way to improve the performance of leather materials is to coat its surface with a layer of protective film
During testing the waterproofing property of fluorinated polyurethane (FPU) coating by using an isopropanol standard test solution (Figure 7i), we found that the commercial C8 waterproofing agent coating whitened after the test (Figure 7ia), while our prepared FPU waterproofing coat‐
During testing the waterproofing property of FPU coating by using an isopropanol standard test solution (Figure 7i), we found that the commercial C8 waterproofing agent coating whitened after the test (Figure 7ia), while our prepared FPU waterproofing coating did not show any whitening phenomenon (Figure 7ib)

Summary

Introduction

Leather has a wide range of applications, but its development is limited by its easy aging and poor properties in terms of water proofing and scratch resistance.The main way to improve the performance of leather materials is to coat its surface with a layer of protective film. To further improve the waterproof, oil-resistant and anti-smudge properties of PU coatings, fluorinated polyurethane (FPU) waterproofing agent is prepared often by introducing fluorine-containing groups into the PU molecular structure. The FPU retains the special structural characteristics of PU itself, which can bring lots of excellent properties to the material, for example good film formation, wear resistance and toughness. The introduction of fluorine-containing segments endows polyurethane-based materials with other special properties (like excellent waterproof, oilproof and anti-smudge properties [14,15,16,17,18,19,20,21,22]) due to its low surface energy [23], which determines that the FPU will have better application prospects in more fields than the traditional PU. The introduction of long-chain perfluoroalkyl (LF) groups to PU is currently the most used method for FPU preparation through implanting fluorinated polyols as soft chain segments [24,25], perfluorinated alcohols as end sealants [26,27], or fluorinated compounds with multi-functional groups as chain extenders [28,29,30]

Methods

Results

Conclusion