Biodegradable aliphatic-aromatic copolyesters, methods of manufacture, and articles thereof

A biodegradable composition comprising a combination of:

• (i) from more than 10 to 59.99 wt. %, based on the total weight of the composition, of an aliphatic aromatic copolyester having a number average molecular weight of at least 20,000 Daltons and a polydispersity index from 2 to less than 6, wherein the aliphatic aromatic copolyester comprises the following groups incorporated into the copolyester via glycolysis and polymerization:
• (a) a first dihydric alcohol group derived from a first dihydric alcohol selected from the group consisting of ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butanediol, 2,3-butanediol, 1,4-butanediol, tetramethyl cyclobutanediol, isosorbide, cyclohexanedimethanol, hexylene glycol, bio-derived diols, and a combination thereof,
• (b) an aromatic dicarboxylic acid group derived from a reaction of
• (bi) the first dihydric alcohol,
• (bii) an aromatic polyester selected from the group consisting of poly(ethylene terephthalate), poly(butylene terephthalate), polytrimethylene terephthalate, and a combination thereof, and
• (biii) an aliphatic dicarboxylic acid having the general formula (CH2)m(COOH)2 where m is an integer from 2 to 10,
• (c) an aliphatic dicarboxylic acid group derived from the aliphatic dicarboxylic acid having the general formula (CH2)m(COOH)2 where m is an integer from 2 to 10,
• (d) a second dihydric alcohol group derived from the aromatic polyester and incorporated into the aliphatic aromatic copolyester when the aromatic polyester reacts with the first dihydric alcohol and the aliphatic dicarboxylic acid, wherein the second dihydric alcohol group is the residue of ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butanediol, 2,3-butanediol, 1,4-butanediol, tetramethyl cyclobutanediol, isosorbide, a cyclohexanedimethanol, a hexylene glycol, a bio-derived diol, or a combination thereof,
• (e) the residue of from 0 to 0.10 wt. %, based on the aliphatic-aromatic copolyester, of a phosphate compound, and
• (f) the residue of from 0 to 1.50 wt. %, based on the aliphatic-aromatic copolyester, of an addition copolymer comprising the residue of a glycidyl monomer;
• (ii) from more than 40 to less than 89.99 wt. %, based on the total weight of the composition, of an aliphatic polyester, aliphatic polycarbonate, starch, aromatic polyester, cycloaliphatic polyester, polyesteramide, or aromatic polycarbonate;
• and
• (iii) from 0.01 to 5.00 wt. %, based on the total weight of the composition, of a nucleating agent, an antioxidant, a UV stabilizer, a plasticizer, an epoxy compound, a melt strength additive, or a combination thereof;
• wherein the wt. % of (i), (ii), and (iii) totals 100 wt. %;
• and
• wherein a bar having a thickness of 3.2 mm molded from the composition has
• a notched Izod impact strength of at least 920 μm determined in accordance with ASTM D256 at 23° C., and
• a flexural modulus of at least 750 MPa determined in accordance with ASTM D790.