Hydrogenated Glycerol Ester of Rosin HGR-80

Raw rosin contains oxidation-prone conjugated diene systems (abietic acid, dehydroabietic acid) that oxidize and yellow during processing and UV exposure. Catalytic hydrogenation saturates these double bonds, converting them to dihydro- and tetrahydroabietic acid structures with no active sites for photo-oxidative yellowing. HGR-80 achieves Gardner color ≤1 (nearly colorless) versus Gardner ≤6 for standard GER-80, and maintains this color under thermal stress (ΔE ≤2 after 24h/100°C). This makes HGR-80 the required material for: water-white clear varnishes over pale substrates, non-yellowing hot-melt book-binding adhesives, acrylic pressure-sensitive adhesives for masking tapes where tackifier yellowness would show, and food packaging interior coatings requiring FDA compliance and absence of color migration.