Sequential Esterification—Diels-Alder Reactions for Improving Pine Rosin Durability within Road Marking Paint

Abstract

Pine rosin, which is derived from Pinus merkusii resin, a natural product, has demonstrated potential as a road marking binder. Although pine rosin has an excellent shinning property, it has some limitations, such as instability and color change. To tackle these issues, modified rosin has been developed through sequential esterification and Diels–Alder reactions, and it has shown better properties than untreated rosin. In this study, from the evaluation of untreated and treated rosins, the treated rosin showed some improvements, such as a lower acid value and higher stability, as shown by the color consistency during the oxidation test at 150 °C for 24 h in open-air conditions. Additionally, as road marking paint, the modified rosin is blended with blending materials in the range of 18–28 wt.%. The modified rosin has a softening point of 170–210 °C, a hardness of 50–71 HD, and a weight loss of 1.33–5.12 mg during the wearing test. These results are comparable to or better than those of commercially available road marking products.

Recent Progress on Catalytic of Rosin Esterification Using Different Agents of Reactant

“…Because of their biocompatibility, rosin and its by-products are being investigated in the pharmaceutical industry as an encapsulating agent for drug delivery [11]. Gum rosin is also used in solder flux [12] and road-marking paint [2,13].…”

“…As a result, the raw material's properties allow it to be employed in more applications [20]. [2,21,22]).…”

“…For example, if methanol is used as a reactant, the rosin ester can take the form of a methyl ester, which has fuel-like properties [23]. If glycerol and pentaerythritol are used as a reactant, a solid rosin ester will be formed with a high softening point that could exceed 100 • C. This product is suitable for raw material of road marking paint [2,20]. When PEG is used in the reaction, the rosin ester will dissolve in water and this product can be used as drug delivery [24].…”

“…Rosin, also known as colophony, is a natural substance obtained from pine trees that is biodegradable and abundant with a wide range of applications [1]. Indonesia, China, and Brazil are the main producers of pine sap, which is used to make turpentine (resin) and gum rosin [2]. Indonesia had a total pine-based production capacity of 141.150 tons in 2022 [3].…”

Development and Evaluation of Vegetable Resin Bio-Binders as Technological Alternatives to Bitumen

“…Finally, it is better to highlight that some of the abovementioned researchers used resin in modified forms through chemical processes such as esterification or hydrogenation [34,35]. Although these modifications result in a more thermally stable product, they require high reaction temperatures and long residence times [34][35][36], which may increase costs and reduce the potential environmental benefits associated with the use of renewable materials, thereby increasing emissions during the product's manufacturing [37].…”