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US 6,723,768 B2Granted
Polyester/polycarbonate blends with reduced yellowness
AssigneeEastman Chemical Company
InventorsValerie Sue Adams, Emmett Dudley Crawford, Michael Eugene Donelson, Douglas Stephens McWilliams
Life of this patent
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Abstract
Thermoplastic compositions of polyester/polycarbonate blends have reduced yellowness and improved thermal and melt stability when the polyester is produced with a reduced level of a titanium-containing catalyst in an amount of from about 1 to about 30 ppm elemental titanium, with ppm based on the total weight of the polyester.
Claims6
In a thermoplastic composition comprising a miscible blend of:
- (a) about 1 to about 99 weight percent of a polyester comprising:
- (i) an acid component comprising repeat units from about 80 to 100 mole percent terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid or mixtures thereof and from 0 to about 20 mole percent of other dicarboxylic acid units having from about 4 to about 40 carbon atoms, wherein the total mole percent of the acid component is equal to 100 mole percent, and
- (ii) a diol component comprising repeat units from about 40 to 100 mole percent 1,4-cyclohexanedimethanol, from 0 to about 60 mole percent ethylene glycol, and from 0 to about 20 mole percent of other diol units having from 3 to about 12 carbon atoms, wherein the total mole percent of diol component is equal to 100 mole percent;
- and
- (b) about 99 to about 1 weight percent of a polycarbonate of 4,4-isopropylidenediphenol;
- the improvement comprising the polyester comprising (i) catalyst residues of a titanium-containing catalyst compound in an amount of from about 1 to about 20 ppm elemental titanium, (ii) catalyst residues of a pre-polycondensation phosphorus-containing compound in an amount of from about 1 to about 150 ppm elemental phosphorus, (iii) from about 1 to about 10 ppm of at least one copolymerizable compound of a 6-arylamino-1-cyano-3H-dibenz[f,ij]isoquinoline-2,7-dione or a 1,4-bis(2,6-dialkylanilino)anthraquinone in combination with at least one bis anthraquinone or bis anthrapyridone(6-arylamino-3H-dibenz[f,ij]isquinoline-2,7-done) compound, wherein the compounds contain at least one polyester reactive group;
- (iv) from about from 0.01 to about 0.35 weight percent, based on the total weight of the blend, of distearyl pentaerythritol diphosphite as a post-polycondensation phosphorus-containing compound;
- and (v) optionally, an ester exchange catalyst in an amount of from about 1 to about 150 ppm of an active element utilized when the acid component is derived from a diester of the dicarboxylic acid, with ppm based on the total weight of the polyester.
5 more elements
Dependencies are inferred from the claim text.