Polymer, process and composition

There are described q oligomer-polymer composition [optionally substantially free of styrene (=20 wt-% of a higher itaconate diester (preferably dibutyl itaconate-DBI); (b) less than 23 wt-% acid monomer but also sufficient to have an acid value less than 150 mg KOH/g of polymer, (c) optionally with less than 50 wt-% of other itaconate monomers, and (d) optionally less than 77 wt-% of other monomers not (a) to (c). The DBI may be biorenewable. One embodiment is an aqueous dispersion of vinyl sequential polymer of two phases: A) 40 to 90 wt-% of a vinyl polymer A with Tg from −50 to 30° C.; and B) 10 to 60 wt-% of a vinyl polymer B with Tg from 50 to 130° C.; where DBI is used to prepare A and/or B and polymer A has from 0.1 to 10 wt-% of at least one acid-functional olefinically unsaturated monomer. Another embodiment is an aqueous polymer coating composition of a vinyl oligomer C of Mw from 1,000 to 150,000 g/mol and an acid value>5 mgKOH/g; and a vinyl polymer D of Mw>=80,000 g/mol and an acid value