Preparation of high molecular weight and elastic copolyester by reactive extrusion with diisocyanate compound for laser printing process

Abstract

A branched copolyester was synthesized using dimethyl terephthalate (DMT), 2,2-bis[4-(2-hydroxypropoxy)phenyl] propane, ethylene glycol (EG) and 2-(hydroxymethyl)-2-ethylpropane-1,3-diol (trimethylol propane, TMP). The branched copolyester and p -phenylene diisocyanate (PPDI) were melt extruded to enhance the melt viscosity and elasticity for use as a toner binder in the laser printing process. The effects of PPDI content on melt, thermal and rheological properties of the chain-extended copolyester were investigated. The melt fl ow index (MI) decreased with increasing amount of PPDI, due to a reaction between the hydroxyl chain end and isocyanate group. The storage modulus, loss modulus and complex viscosity of the chain extended copolyester were higher and the modifi ed Cole-Cole plots revealed the chain extended copolyester to have higher elasticity than that of the branched copolyester. The chain extended copolyester exhibited suitable melt and rheological properties for applications as a toner binder in the laser printing processes.

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“…Moreover, specific chain extenders, such as tetraglycidyl-4,4-diamino-diphenylmethane (TGDDM), are vital in the enhancement of TPE-E molecular weights. Consequently, TPE-E would have improved rheological, mechanical, and thermal characteristics [4].…”