High melting point flame retardant crystal and method for manufacturing the same, epoxy resin composition containing the flame retardant, and prepreg and flame retardant laminate using the composition
US9371438B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 16, 2012 |
| Grant date | Jun 21, 2016 |
| Priority date | — |
| Expiry date | Aug 10, 2034 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08J2363/00
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
Disclosed herein is a method of preparing a high-melting point flame retardant crystal, comprising the steps of: reacting 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide with 1,4-naphthoquinone in an inert solvent having a dielectric constant of 10 or less to reduce a content of by-products, thereby obtaining a reaction composition; and dissolving the reaction composition in any one solvent selected from the group consisting of ethyleneglycol, propyleneglycol, diethyleneglycol, cyclohexanone, benzyl alcohol, acetate ester, benzoate ester and a mixture thereof to recrystallize and refine the reaction composition, thereby obtaining high-melting point retardant crystal, represented by Formula 1, having a start melting point of 280° C. or more and a melting point of 291° C. or more, which are measured by differential thermogravimetric analysis.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.