Calcium treatment of alkyl-tin stabilizers
View Patent ↗An alkyl-tin stabilizer composition is treated with a calcium compound to reduce the carboxylate content level of the stabilizer.
1. A method comprising reacting an alkyl-tin stabilizer composition having a first level of carboxylate content with a calcium compound, filtering treated stabilizer composition and collecting filtered stabilizer composition with a second level of carboxylate content that is lower than the first level of carboxylate content.
2. The method of claim 1 , further comprising adding the filtered stabilizer composition to a polyvinyl chloride composition.
3. The method of claim 1 , wherein the alkyl-tin stabilizer composition includes an alkyl-tin thioglycolate stabilizer and there is less alkyl-tin salt of thioglycolic acid present in the second level of carboxylate content than in the first level of carboxylate content.
4. The method of claim 1 , wherein the alkyl-tin stabilizer composition includes an alkyl-tin thioglycolate stabilizer selected from the group consisting of butyl-tin thioglycolate stabilizer, methyl-tin thioglycolate stabilizer and octyl-tin thioglycolate stabilizer.
5. The method of claim 1 , wherein the calcium compound includes at least one of calcium oxide and calcium hydroxide.
6. The method of claim 1 , wherein the filtered stabilizer composition has less coloring than the alkyl-tin stabilizer composition prior to reacting with the calcium compound.
7. The method of claim 1 , wherein the filtered stabilizer composition is less cloudy than the alkyl-tin stabilizer composition prior to reacting with the calcium compound.
8. The method of claim 1 , further comprising providing at least one of calcium oxide and calcium hydroxide in an amount of 0.25% to 5.0% by weight of the alkyl-tin stabilizer composition for said reacting with the alkyl-tin stabilizer composition.
9. The method of claim 1 , wherein said reacting and filtering are carried out with a filter media including at least one of calcium oxide and calcium hydroxide.
10. The method of any of claim 1 , wherein said reacting is carried out by adding at least one of calcium oxide and calcium hydroxide to the alkyl-tin stabilizer solution prior to said filtering.
11. The method of any of claim 1 , further comprising providing a combination of calcium oxide and calcium hydroxide in a by weight ratio of from 1:1 to 1:5 for said reacting with the alkyl-tin stabilizer composition.
12. The method of claim 1 , wherein said reacting is conducted at from approximately 50° C. to approximately 60° C.
13. The method of claim 9 , wherein said filter media includes a 5:1:2 by weight ratio of calcium oxide: calcium hydroxide: anhydrous Na2SO4.
14. The method of claim 9 , wherein said filter media includes a 1.5:1.5:3:3 by weight ratio of CaO:Ca(OH)2:Na2So4: Celite.
15. The method of claim 2 , wherein the alkyl-tin stabilizer composition includes an alkyl-tin thioglycolate stabilizer selected from the group consisting of butyl-tin thioglycolate stabilizer, methyl-tin thioglycolate stabilizer and octyl-tin thioglycolate stabilizer.
16. The method of claim 15 , wherein the calcium compound includes at least one of calcium oxide and calcium hydroxide.
17. The method of claim 16 , further comprising providing at least one of calcium oxide and calcium hydroxide in an amount of 0.25% to 5.0% by weight of the alkyl-tin stabilizer composition for said reacting with the alkyl-tin stabilizer composition.
18. The method of claim 17 , wherein said reacting and filtering are carried out with a filter media including at least one of calcium oxide and calcium hydroxide.
19. The method of claim 18 , wherein said filter media includes a 5:1:2 by weight ratio of calcium oxide: calcium hydroxide: anhydrous Na2SO4.
20. The method of claim 16 , further comprising providing a combination of calcium oxide and calcium hydroxide in a by weight ratio of from 1:1 to 1:5 for said reacting with the alkyl-tin stabilizer composition.