Agfa Gevaert Nv

Jan H Van Hove

August M Marien

Victor Franciscus De Beul

Roger Isidoor De Saedeleer

Johannes M Verheijen

Ludovicus Maria Hellemans

A continuous direct esterification and polycondensation process is disclosed in view of the production of polyester comprising units of ethylene terephthalate as the major repeating units, said polyester being substantially improved in particular in respect of its electroconductive properties. Said process comprises supplying terephtalic acid and ethylene glycol to bis(betahydroxy ethyl) terephthalate or its oligomer so as to carry out esterification, followed by polycondensing the resulting oligomer under increasingly reduced pressure, and wherein a solution in ethylene glycol of an electroconductivity enhancing additive, preferably a metallic salt, such as e.g. magnesium acetate, is added to the oligomer reaction mixture when the esterification rate has reached at least 80% and characterized in that said ethylene glycol solution is added to the oligomer reaction mixture in such manner that escape of the added ethylene glycol out of the said oligomer reaction mixture is prohibited.

Process for the production of polyester with increased

In an extrusion coating process of the flow-stretch type in which a ribbon of an aqueous gelatin coating composition is extruded through an elongated orifice onto a moving support and becomes stretched and attenuated in thickness between the orifice and support, at least one visco-elasticity enhancing agent is added to the coating composition in sufficient amount as to disproportionately increase the elasticity of the composition compared to its viscosity so as to render the composition stretchable at viscosities which are substantially reduced compared to what would otherwise be necessary for flow-stretch coatability.

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Berchem, Belgium

Jan H Van Hove