SULFUR-STABILIZED THERMOPLASTIC COMPOSITIONS, METHODS OF MAKING, AND ARTICLES FORMED THEREFROM

1 . A thermoplastic composition comprising:

a high heat copolycarbonate comprising

2-95 mole percent of high heat carbonate units derived from a high heat aromatic dihydroxy monomer, wherein a polycarbonate homopolymer derived from the high heat aromatic dihydroxy monomer has a glass transition temperature of 175-330° C. determined by differential scanning calorimetry as per ASTM D3418 with a 20° C./min heating rate, and

5-98 mole percent of a low heat carbonate units derived from a low heat aromatic monomer, wherein a polycarbonate homopolymer derived from the low heat aromatic monomer has a glass transition temperature of less than 170° C. determined by differential scanning calorimetry as per ASTM D3418 with a 20° C./min heating rate, each based on the sum of the moles of the carbonate units; and

a sulfur-containing stabilizer compound, wherein the sulfur-containing stabilizer compound is a thioether carboxy compound, a thioether dicarboxy compound, a thioether ester compound, or a combination thereof, and wherein the sulfur-containing stabilizer compound is present in an amount effective to provide 5-50 parts per million by weight of added sulfur, based on the total parts by weight of the copolycarbonate, wherein a source of the added sulfur is the sulfur-containing stabilizer.

2 . The thermoplastic composition of claim 1 , comprising:

20-90 mole percent, or 30-80 mole percent of the high heat carbonate units; and

10-80 mole percent, or 20-70 mole percent of low heat carbonate units.

3 . The thermoplastic composition of claim 1 , wherein the high heat aromatic carbonate units are derived from 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethyl-cyclohexane, 4,4′-(1-phenylethylidene)bisphenol, 4,4′-(3,3-dimethyl-2,2-dihydro-1H-indene-1,1-diyl)diphenol, 1,1-bis(4-hydroxyphenyl)cyclododecane, 3,8-dihydroxy-5a,10b-diphenyl-coumarano-2′,3′,2,3-coumarane, or a combination thereof.

4 . The thermoplastic composition of claim 1 , wherein the high heat carbonate units are derived from, 4′-(1-phenylethylidene)bisphenol, 4,4′-(3,3-dimethyl-2,2-dihydro-1H-indene-1,1-diyl)diphenol, or a combination thereof.

5 . The thermoplastic composition of claim 1 , wherein the low heat carbonate units are derived from bisphenol A.

6 . The thermoplastic composition of claim 1 ,

wherein the high heat copolycarbonate further thioether carbonyl endcaps of the formula —C(═O)-L-S—R, wherein L is a C 1-12 aliphatic or aromatic linking group and R is a C 1-20 alkyl, C 6-18 aryl, or C 7-24 arylalkylene;

or wherein the endcaps are of the formula

or a combination thereof.

7 . The thermoplastic composition of claim 1 , wherein the sulfur-containing stabilizer compound is soluble in an organic solvent for the copolycarbonate and is substantially insoluble in an aqueous solvent at a pH of less than 11.

8 . The thermoplastic composition of claim 1 , wherein the sulfur-containing stabilizer compound comprises a C 6-40 hydrocarbon chain.

9 . The thermoplastic composition of claim 1 , wherein the sulfur-containing stabilizer compound is dilauryl thiodipropionate, dicetyl thiodipropionate, dimyristyl thiodipropionate, distearyl thiodipropionate, ditridecyl thiodipropionate, 2-bis[[3-(dodecylthio)-1-oxopropoxy]methyl]propane-1,3-diyl bis[3-(dodecylthio)propionate, or a combination thereof.

10 . The thermoplastic composition of claim 1 , further comprising an organosulfonic stabilizer present in an amount effective to provide 2-40 ppm by weight of added sulfur, based on the total parts by weight of the copolycarbonate, wherein a source of the added sulfur is the organosulfonic stabilizer.

11 . The thermoplastic composition of claim 1 , having one or more of the following properties:

less than 5 parts per million by weight each of lithium, sodium, potassium, calcium, magnesium, ammonium, chlorine, bromine, fluorine, nitrite, nitrate, phosphite, phosphate, sulfate, formate, acetate, citrate, oxalate, trimethylammonium, triethylammonium, or a combination thereof as measured by ion chromatography;

the high heat copolycarbonate is prepared from monomers wherein one or more of the monomers has a purity of at least 99.6%, as determined by high performance liquid chromatography; or

a yellowness index of less than or equal to 30, as measured by ASTM D1925 on a 3.2 mm plaque.

12 . The thermoplastic composition of claim 1 , wherein the high heat aromatic hydroxyl monomer and the low heat aromatic hydroxyl monomer have a sulfur content of less than 5 parts per million by weight.

13 . A method of making the copolycarbonate of claim 1 , the method comprising polymerizing a composition comprising:

2-95 mole percent of the high heat aromatic dihydroxy monomer,

5-98 mole percent of the low heat aromatic dihydroxy monomer, each based on the sum of the moles of the carbonate units; and

the sulfur-containing stabilizer compound, wherein the sulfur-containing stabilizer compound is present in an amount effective to provide 5-50 parts per million by weight of added sulfur, based on the total parts by weight of the copolycarbonate, wherein the source of the added sulfur is the sulfur-containing stabilizer.

14 . An article comprising the thermoplastic composition of claim 1 .

15 . The thermoplastic composition of claim 6 , wherein the thioether carbonyl endcaps are of the formula

or a combination thereof.

16 . The thermoplastic composition of claim 8 , wherein the sulfur-containing stabilizer compound comprises a C 6-40 alkyl group or a C 10-30 alkyl group.

17 . The method of claim 13 , wherein the low heat aromatic dihydroxy monomer comprises bisphenol A.

18 . The article of claim 14 , wherein the article is a camera lens, a sensor lens, an illumination lens, a safety glass lens, an ophthalmic corrective lens, or an imaging lens.

19 . The article of claim 14 , wherein a surface of the article is hard coated or metallized.