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US 4,396,769 AGranted
Process for preparing crystalline, non-dusting bis(2,2,6,6-tetramethylpiperidin-4-yl) sebacate
AssigneeCiba-Geigy Corporation
InventorsAnibal L. Ferreira, Robert E. Stahlbush
Life of this patent
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Abstract
Crystalline, non-dusting bis(2,2,6,6-tetramethylpiperidin-4-yl) sebacate is made by heating the sebacate ester to a temperature above its melting point and then slowly cooling the melt with agitation to form the product in a crystalline, non-dusting form. This ester, also known as TINUVIN 770, is a valuable commercial light stabilizer for a myriad of substrates.
Claims4
A process for preparing bis(2,2,6,6-tetramethylpiperidin-4-yl) sebacate in a crystalline, non-dusting form having a particle size greater than 100 microns and with a volatiles content less than 0.5% by weight, which comprises
- heating bis(2,2,6,6-tetramethylpiperidin-4-yl) sebacate, in the form of a friable, dusting powder or wet paste, to above its melting point, at a temperature between 83.degree. and 95.degree. C. under a pressure of 5 to 150 mm Hg with agitation to form a uniform melt of the sebacate, and then
- slowly cooling the melt, with continued agitation, to a temperature between 70.degree. and 83.degree. C. to cause the sebacate to crystallize from the melt in a crystalline, non-dusting form.
Dependencies are inferred from the claim text.