A gum base comprising at least one crosslinked branched aliphatic biodegradable polyester comprising repeat units formed from at least one polyol having three to four hydroxy groups, or ester thereof, at least one dibasic acid, or ester thereof, and at least one long chain monocarboxylic acid, or ester thereof. The process of producing a crosslinked branched aliphatic biodegradable polyester gum base by reactive extrusion is also included.

A process for making a crosslinked branched polyester gel from at least two pregel compositions comprising: a) reacting precursor repeat units formed from (1) at least one polyol having three or more hydroxyl groups or esters thereof, (2) at least one aliphatic or aromatic polyfunctional acid or ester thereof, or a mixture thereof; and (3) optionally at least one long chain aliphatic carboxylic acid or ester thereof, or aromatic monocarboxylic acid or ester thereof, or mixture thereof, to substantial completion in separate reactors to produce in a first reactor a first composition comprising a pre-gel having carboxyl end groups and to produce in a second reactor a second composition comprising a pre-gel having hydroxyl end groups, b) combining the first and second compositions to form a mixture; and c) processing the mixture in an extruder, a continuous processor, or a container to convert the mixture into a crosslinked branched polyester gel.

The invention relates to a process for making a high molecular weight pre-gel for a cross-linked branched polyester comprising: a) reacting polyester precursor repeat units via condensation polymerization in a continuous or semi-continuous, or batch reactor stage to form a low molecular weight pre-gel; and b) further reacting the low molecular weight pre-gel via condensation polymerization in a continuous thin-film reactive vacuum processing stage to form a high molecular weight pre-gel.

A gum base comprising a crosslinked branched polyester gel prepared from the process comprising: a) providing a first pre-gel composition having carboxyl end groups; b) providing a second pre-gel composition having hydroxyl end groups; c) removing either or both of the first and second pre-gel compositions from their respective reactors; d) combining the first and second pre-gel compositions to form a mixture; and e) processing the mixture in an extruder, a continuous processor, or a container thereby providing a crosslinked branched polyester gel.