Study on novel rosin‐based polyurethane reactive hot melt adhesive

Abstract

Chain extender is a major additive in polyurethane adhesive preparation, which has a great influence on its molecular weight, green strength, and thermal resistance. In this work, we first synthesized a novel rosin‐based chain extender to replace conventional petroleum derived ones due to rosin was a renewable and low cost natural material. Afterward, the as‐prepared rosin‐based chain extender reacted with the isocyanate‐terminated polyurethane prepolymer to prepare polyurethane reactive hot melt adhesive (PURHMA). Rosin contains rigid hydrophenanthrene ring, which may have good effect on the thermal and mechanical properties of PURHMA. Consequently, the characterization of the thermal and physical properties of sustainable PURHMA was made using differential scanning calorimetry, X‐ray diffraction, dynamic mechanical thermal analyzer, as well as thermogravimetric analysis. Eventually, the adhesion performance of PURHMA on wood substrates were investigated by adjusting the amount of rosin‐based chain extender in the adhesive system. It was found that with the increase of the chain extender content, the thermal resistance, mechanical property, and adhesion property of PURHMA were significantly improved. The tensile strength of adhesive joints increased from 4.15 to 15.53 MPa, and the ultimate lap shear strength increased from 5.76 to 8.92 MPa. More strikingly, the rosin‐based PURHMA exhibited excellent bonding strength even after aging in water (less than 18%).

Eco-Friendly Polyurethane Reactive Hot-Melt Adhesive Derived from Poly(ε-caprolactone-co-lactic acid) Diols

“…As shown in Figure c, the green strength of all PURHAs on a PC substrate was the highest due to the reaction of NCO groups with the active hydrogen-containing substances on PC and the formation of hydrogen bonds and dipole–dipole interactions between carbonyl groups of PURHAs and PC . Moreover, the soft segment crystallization also affects the green strength . PUHRA-PCL from PCL-diol exhibited the highest green strength on PC substrates among the synthesized PURHAs, which may correlate to the highest crystallinity of PCL-diol.…”

Sustainable cycloaliphatic polyurethanes: from synthesis to applications

“…Due to the high molar masses and high chain entanglements of the bulky cycloaliphatic structure of the new diol (23), the thermal stability and the mechanical properties of the final TPUs increased. 256 Other polyols, ( 24) and (25) from abietic acid, have also been described in recent studies. Tall oil with different rosin contents ranging from 2% to 20% reacted with diethanolamine and triethanolamine secondary amines or OH groups to form polyols, (24) and (25), respectively.…”

“…Due to the high molar masses and high chain entanglements of the bulky cycloaliphatic structure of the new diol ( 23 ), the thermal stability and the mechanical properties of the final TPUs increased. 256…”

Low-temperature activable, carbon dioxide based, highly adhesive and degradable oligo-urethane and its potential application as an auto-detachable dressing

“…[1][2][3] More importantly, HMAs work well in complicated environments and exhibit high adhesive strength for various substrates (including metal and non-metal materials). 4,5 Most of the commercialized HMAs are polyurethane based thermosetting HMAs (PUR-HMAs). PUR-HMAs contain mainly low molecular weight segments and multifunctional isocyanate-terminated chemicals, 6,7 and the blocked polyurethane chain can form a chemically cross-linked network structure.…”