Phosphite stabilizers for ionomeric polyester compounds
The use of oxidizable phosphorus or phosphorous stabilizers, such as the phosphites, to reduce the color formation of the ionomeric polyester compositions is disclosed.
1. A process for thermally treating an article, which is a preform, wherein the process comprises grinding the preform and heating the ground preform to a temperature above 70° C. for more than 2 minutes in the presence of oxygen, wherein the article comprises an oxidizable phosphorus compound and an ionomeric polyester derived from at least one ionomeric monomer, wherein at least 90% of the acid units of the ionomeric polyester are derived from the group consisting of terephthalic acid, isophthalic acid, orthophthalic acid, 2,6 naphthalene dicarboxylic acid and their respective dimethyl esters, wherein the composition has a total amount of polyester which is the amount of ionomeric polyester plus the amount of non-ionomeric polyester, if present, and the ionomeric polyester has been catalyzed with an antimony compound, wherein elemental antimony reduced by the oxidizable phosphorus compound is less than 5 ppm of the total amount of polyester.
2. The process of claim 1 wherein the ionomeric monomer is selected from the group consisting of the metal salt of a sulfonate of terephthalic acid, isophthalic acid, orthophthalic acid, 2,6 dimethylnaphthalic acid, and their respective dimethyl esters.
3. The process of claim 1 , wherein the oxidizable phosphorus compound is selected from the group consisting of triphenylphosphite, trimethylphosphite, triethylphosphite, (2,4,6-tri-t-butylphenol)2-butyl 2 ethyl 1,3-propanediol phosphite, bis (2,4-di-tert-butylphenyl) Pentaerythritol diphosphite and tetrakis(2,4-di-tert-butylphenyl) 4,4-biphenyldiphosphonite.
4. The process of claim 2 , wherein the oxidizable phosphorus compound is selected from the group consisting of triphenylphosphite, trimethylphosphite, triethylphosphite, (2,4,6-tri-t-butylphenol)2-butyl 2 ethyl 1,3-propanediol phosphite, bis (2,4-di-tert-butylphenyl) Pentaerythritol diphosphite and tetrakis(2,4-di-tert-butylphenyl) 4,4-biphenyldiphosphonite.
5. The process of claim 1 , wherein the oxidizable phosphorus compound is present in the range of 15 to 150 parts phosphorus to million parts total polyester polymer.
6. The process of claim 2 , wherein the oxidizable phosphorus compound is present in the range of 15 to 150 parts phosphorus to million parts total polyester polymer.
7. The process of claim 3 , wherein the oxidizable phosphorus compound is present in the range of 15 to 150 parts phosphorus to million parts total polyester polymer.
8. The process of claim 1 , wherein the oxidizable phosphorus compound is present in the range of 30 to 100 parts phosphorus to million parts total polyester polymer.
9. The process of claim 2 , wherein the oxidizable phosphorus compound is present in the range of 30 to 100 parts phosphorus to million parts total polyester polymer.
10. The process of claim 3 , wherein the oxidizable phosphorus compound is present in the range of 30 to 100 parts phosphorus to million parts total polyester polymer.
11. The process of claim 1 wherein the article is essentially void of elemental antimony reduced by the oxidizable phosphorus compound.
12. The process of claim 2 wherein the article is essentially void of elemental antimony reduced by the oxidizable phosphorus compound.
13. The process of claim 3 wherein the article is essentially void of elemental antimony reduced by the oxidizable phosphorus compound.
14. The process of claim 7 , wherein the article is essentially void of elemental antimony reduced by the oxidizable phosphorus compound.