Polyester/polycarbonate blends with reduced yellowness

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.

1 - 42 . (canceled)  
     
     
         43 . A polyester composition having an inherent viscosity of from about 0.6 to about 1.2 dl/g measured at 25° C. in a solvent mixture consisting of 60% by weight phenol and 40% by weight tetrachloroethane and the polyester comprising: 
 (a) an acid component comprising repeat units from terephthalic acid, isophthalic acid, and mixtures thereof;    (b) a diol component comprising repeat units from about 40 to 100 mole percent 1,4-cyclohexanedimethanol and about 0 to about 60 mole percent ethylene glycol;    and    (c) catalyst residues consisting essentially of (i) a titanium-containing catalyst compound in an amount of about 1 to about 15 ppm elemental titanium, (ii) a pre-polycondensation phosphorus-containing compound in an amount of about 45 to about 100 ppm elemental phosphorus, (iii) from about 1 to about 5 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, and (iv) optionally, an ester exchange catalyst in an amount of from about 10 to about 65 ppm of an active element utilized when the acid component is derived from a diester of the dicarboxylic acid;    wherein the acid component is based on 100 mole percent and the diol component is based on 100 mole percent and ppm are based on the total weight of the polyester.    
     
     
         44 . The thermoplastic composition of  claim 43  wherein the polyester comprises from about 95 to 100 mole percent of terephthalic acid, from about 58 to about 66 mole percent 1,4-cyclohexanedimethanol and from about 42 to about 34 mole percent of ethylene glycol.  
     
     
         45 . The thermoplastic composition of  claim 43  wherein the polyester comprises 100 mole percent 1,4-cyclohexanedimethanol, from about 22 to about 30 mole percent isophthalic acid, and from about 78 to about 70 mole percent terephthalic acid.  
     
     
         46 . 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 of 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 of 1,4-cyclohexanedimethanol, from 0 to about 60 mole percent of 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; and    (iv) 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, and the blend further comprising from about 0.01 to about 0.35 weight percent of a post-polycondensation phosphorus-containing compound, based on the total weight of the blend, having one of the formulas (a)-(e):                          wherein each of R 1 , R 2 , and R 3  represents a hydrogen atom, an alkyl group containing 1 to 20 carbon atoms, an aryl group containing 6 to 20 carbon atoms, an arylalkyl group containing 7 to 20 carbon atoms, or an OR group in which R is a hydrogen atom, an alkyl group containing 1 to 20 carbon atoms, an aryl group containing 6 to 20 carbon atoms, and arylalkyl group containing 7 to 20 carbon atoms; R 1 , R 2 , and R 3  may be different from each other, or at least two of R 1 , R 2 , and R 3  may be the same, or at least two of R 1 , R 2 , and R 3  may form a ring, and metal salts of these phosphorous compounds;    (c)                          wherein R 1  represents a divalent alkyl group having 2-12 carbon atoms or a divalent aryl group having 6-15 carbon atoms; R 2  and R 3  are monovalent alkyl groups having 2-18 carbon atoms, or a monovalent aryl or substituted aryl group having 6 to 15 carbons;                          wherein R 1  represents a divalent alkyl or poly(alkylene oxide) groups having 2-12 carbon atoms or a divalent aryl or substituted aryl group having 6-15 carbon atoms; and                          wherein R 1  and R 2  represent monovalent alkyl groups having 2-18 carbon atoms, or a monovalent aryl or substituted aryl groups having 6-15 carbon atoms.    
     
     
         47 . The thermoplastic composition of  claim 46 , wherein the polyester comprises from about 95 to 100 mole percent of terephthalic acid repeat units as the acid component, and from about 58 to about 66 mole percent or 1,4-cyclohexanedimethanol repeat units and from about 42 to about 34 mole percent of ethylene glycol repeat units as the diol component.  
     
     
         48 . The thermoplastic composition of  claim 46 , wherein the polyester comprises 100 mole percent of 1,4-cyclohexanedimethanol repeat units as the diol component, and from about 22 to about 30 mole percent isophthalic acid repeat units and from about 78 to about 70 mole percent terephthalic acid repeat units as the acid component.  
     
     
         49 . The thermoplastic composition of  claim 46 , wherein the titanium-containing catalyst compound is present in an amount of from about 1 to about 15 ppm elemental titanium.  
     
     
         50 . The thermoplastic composition of  claim 46 , wherein the post-polycondensation phosphorus-containing compound is distearyl pentaerythritol diphosphite.  
     
     
         51 . A molded article formed from the thermoplastic composition of  claim 46 .  
     
     
         52 . A film or sheet formed from the thermoplastic composition of  claim 46.