| 摘要 |
There is described a low VOC, unsaturated alkyd resin obtained by reacting (A) to (E): (A) optionally from 0 to 30% w/w naturally occurring Rosin, comprising from 40 to 80 w/w parts per hundred of Rosin of an unsaturated mono carboxylic acid with at least one C15-25cyclohydrocarbo moiety capable of a Diels Alder or Ene reaction (pref monoacids being abietic acid, palustric acid, levopimaric acid, sandaracopimaric acid, and/or anhydrides thereof); (B) from 25 to 80% w/w of a linear C12-60hydrocarbo carboxylic acid with at least one (preferably at least two conjugated) C═C bonds (=unsaturated fatty acid); (C) optionally from 1 to 30% w/w of an ethylenically unsaturated C5-6hydrocarbo dicarboxylic acid and/or anhydride thereof, being reactive as a dienophile and/or enophile with A and/or B (pref C are itaconic acid, citraconic acid and/or anhydrides thereof); (D) from 1 to 40% w/w of at least one polyol; (E) optionally at least one monomer other than A to D—the total of A to E being 100%. There is a further optional step (II) where more or new (C) may be blended with the alkyd resin; the amount of C in blend being from 1 to 30 parts w/w of 100 parts of monomers (A) to (E)—and where (C) is at least used as a monomer and/or as a diluent in the blend and where alkyd resin (i) has acid value of <50 KOH/g of alkyd; (ii) Mn of >=1200 g/mol (iii) oil length <80; (iv) optionally biorenewable content >=50%. |
