Pentaerythritol Ester Rosin (Light)

Brief Overview

Rosin pentaerythritol ester is a quaternary alcohol ester that shows improved water resistance, alkali resistance, and oxidation resistance, and is thus, more stable. As a result, it has greatly increased potential for industrial applications, such as pressure-sensitive adhesives, hot-melt adhesives, and modifers. However, rosin esterifcation has typically been conducted as an acid/base-catalyzed reaction. Because the carboxyl group of rosin is located on a tertiary carbon atom, the steric hindrance is large, and a high activation energy needs to be overcome for its reaction.

Manufacturing Process

Pentaerythritol Rosin Ester is made from gum rosin or refined natural rosin through esterification with glycerol.  The carboxylic acid group of a rosin acid can be converted to an ester through a reaction with various alcohols. The alcohols typically used to make rosin esters are: Methanol, Triethylene Glycol, Glycerol, Pentaerythritol. The molecular weight and functionality of the alcohol determines the softening point of the subsequent ester. Glycerol with three reactive sites and pentaerythritol with four available hydroxyl groups are the most commonly used alcohols. Methanol with a single hydroxyl group and tri-ethylene-glycol with two reactive sites are used to produce liquid and low softening point esters. Esterification is an equilibrium reaction that can be driven to near completion by removal of water from the reactor, but there will always be some unreacted acid and residual alcohol in the final product. A typical acid number for a pure rosin acid is around 170. A glycerol ester typically has an acid value below 20. The type of alcohol chosen is key to determining the molecular weight of the rosin ester and its softening point. A typical softening point for entaerythritol esters is 105°C.

Adhesives

Pentaerythritol Rosin Ester is widely used as a tackifier in adhesives industry. It is used in hot melt adhesive, hot melt pressure sensitive adhesives, ester gum, phenolic varnishes, bookbinding glue, carpenters glue, structural adhesive, packaging, sealants etc.  Others It is also used to make paint and coatings, printing ink, synthetic rubber and pentaerythritol tetranitrate (PETN), urethane coatings, flame retardant paints, polyvinyl chloride stabilizers, olefins antioxidant and pentaerythritol triacrylate.