Super‐Tough Impregnating Adhesive and Its Impregnated Decorative Materials: Highly Crack‐Resistant Surface Layers Suitable for Extreme Climate Variations

ABSTRACT As the wood‐based panel market expands, impregnated paper is a key surface‐decoration material for furniture, flooring, and construction panels, with melamine‐formaldehyde (MF) adhesive‐impregnated paper prevailing for its adhesion, water resistance, and abrasion resistance. The intrinsic brittleness of MF adhesive, however, makes decorative plywood prone to surface cracking, and moisture fluctuations under hot–cold cycling or extreme climates further shorten service life. We synthesized a hyperbranched polysiloxane (HBPSi‐NH 2 ) from 3‐aminopropyltriethoxysilane (APTES) and 2‐methyl‐1,3‐propanediol (MPD) and used it to toughen MF adhesive. The modified MF adhesive‐impregnated paper was hot pressed onto plywood to evaluate the adhesive, the impregnated paper, and the resulting decorative plywood. Mechanistically, HBPSi‐NH 2 provides SiOC flexible segments that offer low‐energy rotational pathways, while surface SiOH groups form reversible hydrogen bonds with MF NH 2 and OH groups, creating recoverable energy‐dissipation units within the three‐dimensional network. This architecture strengthens HBPSi‐NH 2 /MF interfacial interactions and promotes stress redistribution and energy dissipation under tension, thereby enhancing toughness. At 2 wt% HBPSi‐NH 2 , the 4HBPSi‐NH 2 /MF adhesive‐impregnated paper reached 20.2% elongation at break, nearly double the neat MF counterpart (10.2%). After hot‐press lamination to plywood, the surface showed no detectable cracking. Collectively, these results demonstrate that HBPSi‐NH 2 effectively toughens MF adhesive and helps prevent cracking in decorative plywood.