| abstract |
There are described q oligomer-polymer composition [optionally substantially free of styrene (< 1.5 wt-% of copolymer)] comprising oligomer composition O having a weight average molecular weight of from 1000 to 150,000 g/mol (measured by GPC) and polymer composition P having a weight average molecular weight of at least 80,000 g/mol (measured by GPC) the oligomer composition O and the polymer composition P each independently comprising a copolymer composition comprising: (a) at least 8. 5 wt-% preferably >=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 < 10 mgKOH/g where D is obtained from DBI and the amount of monomers used to form C and D fall into the respective weight ratios 5 to 70 for polymer C and 95 to 30 for polymer D. A further embodiment is an aqueous suspension polymerisation process for preparing vinyl polymer beads from olefinically unsaturated monomers and a free-radical initiator, where at least 10 wt-% of the monomer is DBI. |