Pentaerythritol is an organic compound with the formula C5H12O4. It is part of white crystal powdery solid without poison and odor, which is stable in air. Derivatives of pentaerythritol are components esters, alkyd resins, etc. Pentaerythritol Rosin Ester is one of the derivative of pentaerythritol, with the formula, C25H34O2. It has pale color, and excellent heat stability and anti-aging ability, allowing it to increase the adhesive property of gum. It is soluble in petroleum hydrocarbons, aromatic hydrocarbons, esters and ketones. Moreover, pentaerythritol rosin esters are environmentally friendly and are an alternative to conventional electrical transformer fluids, being both readily biodegradable and non-hazardous in water. These esters have excellent compatibility with various kinds of resins, it may be used across the board with various polymers.
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.
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.
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.