Hydroxypropyl methyl cellulose phthalate and method for producing the same
US11873351B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 29, 2020 |
| Grant date | Jan 16, 2024 |
| Priority date | — |
| Expiry date | Oct 29, 2040 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08L1/32
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
There is provided a method for producing hydroxypropyl methyl cellulose phthalate (HPMCP), including an esterification step of reacting hydroxypropyl methyl cellulose with a carboxybenzoylating agent in the presence of an aliphatic carboxylic acid in a kneader reactor equipped with two or more stirring blades rotating around their own axes and orbitally revolving, to obtain a reaction product solution containing HPMCP; a precipitation step of precipitating the HPMCP by mixing the reaction product solution with water to obtain a suspension of the precipitated HPMCP; and a washing and recovery step of washing the HPMCP in the suspension and recovering the washed HPMCP. Further, there is provided HPMCP having yellowness at 20° C. of 10.0 or less, as determined in a 10% by mass solution of the HPMCP in acetone.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.