Powder thermosetting compositions for preparing coatings with low gloss finish

A thermosetting powder coating composition that, when cured, results in a coating having a gloss of less than 50% measured at an angle of 60° according to ASTM D 523 standard, wherein the composition comprises a binder, wherein the binder comprises a blend of

• (a) an amorphous polyester containing carboxyl groups, rich in isophthalic acid, prepared from an acid constituent comprising from 55 to 100 mol % of isophthalic acid, from 0 to 45 mol % of at least one dicarboxylic acid other than isophthalic acid and from 0 to 10 mol % of a polycarboxylic acid containing at least 3 carboxyl groups and from an alcohol constituent comprising from 60 to 100 mol % of neopentylglycol, from 0 to 40 mol % of at least one dihydroxylated compound other than neopentylglycol and from 0 to 10 mol % of a polyhydroxylated compound containing at least 3 hydroxyl groups, the said amorphous polyester having a glass transition temperature (Tg) of at least 50° C. and an acid number of 15 to 100 mg of
• (b) a semicrystalline polyester containing carboxyl groups prepared either
• (b1) from 1,12-dodecanedioic acid and from a saturated aliphatic diol with a linear chain having from 2 to 16 carbon atoms and optionally from a polycarboxylic acid containing at least 3 carboxyl groups or from a polyol containing at least 3 hydroxyl groups, or
• (b2) from 40 to 100 mol % of 1,12-dodecanedioic acid and from 0 to 60 mol % of an aliphatic dicarboxylic acid with a linear chain having from 4 to 9 carbon atoms, calculated with respect to the total of the dicarboxylic acids, from a cycloaliphatic diol having from 3 to 16 carbon atoms and optionally from a polycarboxylic acid having at least 3 carboxyl groups or from a polyol having at least 3 hydroxyl groups,
• the said semicrystalline polyester having a melting point (Tm) of at least 40° C. and an acid number of 5 to 50 mg of KOH/g;
• and
• (c) a crosslinking agent.