High-Strength, High-Flexibility,\nFormaldehyde-Free\nImpregnated Decorative Paper Based on Polyamide Epichlorohydrin/Poly(vinyl\nalcohol)/Melamine via Layer-by-Layer Self-Assembly

Impregnated decorative paper is an important and high-value\nwood-based\npanel decorative material. However, traditional melamine–urea–formaldehyde\nimpregnated decorative paper (MUFP) suffers from formaldehyde emission\nand brittleness. Therefore, it is crucial to develop high-performance,\nformaldehyde-free, flexible impregnated decorative paper as an alternative\nto MUFP. Here, a layer-by-layer self-assembly strategy is adopted\nto prepare high-performance, formaldehyde-free polyamide epichlorohydrin\n(PAE)/poly(vinyl alcohol) (PVA)/melamine (MA) impregnated decorative\npaper (PMPP). The first PAE resin layer acts as a wet strength agent,\nwhile the second PVA/MA resin layer acts as a toughening agent, forming\na dual network structure through chemical and hydrogen bonding. Due\nto the unique layer-by-layer self-assembled dual-network structure,\nthe elongation at break and work of fracture of PMPP is 4.4% and 265.50\nmJ, respectively. These values are nine- and eight-times higher than\nthose of MUFP, respectively, demonstrating the excellent toughness\nof PMPP. Additionally, PMPP is subjected to water activation and hot\npressing, and its surface properties meet the GB/T15102–2017\nChinese national standard. In addition, the formaldehyde emission\nof PMPP is only 0.01 mg/L, which meets the environmental standards\nof China’s GB/T 28995–2022 (≤1.5 mg/L), Europe’s\nEN 717–1 (≤0.5 mg/L), and Japan’s JAS 234:2003\n(<0.3 mg/L). Thus, this work offers a novel approach to achieve\nhigh-performance, formaldehyde-free, flexible impregnated decorative\npaper.