SOLVENT-FREE CRYSTALLISATION OF PENTAERYTHRITOL TETRAKIS-(3-(3,5-DI-TERT-BUTYL-4-HYDROXYPHENYL) PROPIONATE) AND THE NOVEL .lambda.-CRYSTALLINE FORM THEREOF
CA 1254905 A · Owner: Ciba Specialty Chemicals Holding Inc. · Inventors: Orban, Ivan; Fussenegger, Werner
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Solvent-free cystallisation of pentaerythritol tetrakis-3-(3,5di-tert-butyl-4-hydroxyphenyl)propionate and the novel .lambda.-crystalline form thereof Abstract of the Disclosure, Seeding a melt of pentaerythritol tetrakis-3-(3,5-ditert-butyl-4-hydroxyphenyl)propionate with a small amount of the crystalline .beta.-, .delta.- or .lambda.-modification of this compound in an extruder, kneader or internal mixer at 70°-130°C gives within a, few minutes, pure crystalline product without the use of a hiterto mandatory and environmentally undesirable solvent. Also described is a novel crystalline thermostable .lambda.-modification of pentaerythritol …
Read the whole patent
Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Granted May 30, 1989. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended May 30, 2006.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.