Synthesis and characterization of the Diels-Alder adduct of levopimaric acid with N-phenylmaleimide/p-nonylphenol formaldehyde resins

Abstract

The Diels-Alder adduct of levopimaric acid with N-phenylmaleimide, p-nonylphenol, and p-formaldehyde, taken in various molar ratios, were condensed in acid catalysis to obtain new formaldehyde resins. The presence of the hydrophenthrene moieties in the polymer chain enhanced their solubility and adhesion properties. At the same time, the resulting resins were found to be reasonably thermostable polymers. When the formaldehyde resins were used as tackifiers in the adhesive compositions, they contributed to an increase of both the adhesive strength and the cohesive strength of the resulting pressure-sensitive adhesives.

Keywords:

• Abietic acid
• levopimaric acid
• Diels-Alder adduct
• N-phenylmaleimide
• formaldehyde resins
• pressure-sensitive adhesives