Terpene phenolic resin (TPR) is obtained by the polymerization of the renewable material terpene monomer and phenol. As it has low molecular weight, and glass transition and softening temperature above room temperature, it is commonly used in formulation of adhesives to increase the tack, the stickiness of the surface of the adhesive.
Production of TPR is by the controlled treatment of the monomer in solution in a hydrocarbon diluent with a catalyst such as anhydrous aluminium chloride, of the Friedel-Crafts type. As the polymerization reaction is highly exothermic, provision must be made for adequate agitation and heat exchange. Upon the completion of the reaction, removal of unreacted terpenes, solvent and any low-terpene polymers are done by mixture with low pressure steam. The residual nonvolatile molten TPR is then poured into drums to cool or used in the preparation of resin solutions.
As it possess high softening point and good adhesion, TPR is suitable for use in making chloronorgutta rubber (graft polychloropene rubber) adhesive for PVC artificial leathers. It possess good heat resistance and better solvency for a variety of flexible matter and resins, making it an effective adhesive for a longer duration. TPR can also be used in hot melt adhesive, pressure sensitive adhesives, acrylate adhesive materials and glue adhesives.
It is also used in printing coating agents, printing ink, plastic materials, paint and synthetic leather to enhance the adhesive viscosity.