| 主权项 |
1. A method for the manufacture of a polyetherimide composition having improved melt stability, the method comprising
catalyzing imidization of a 3-substituted phthalic anhydride of the formula with a sulfone diamine selected from 3,3′-diaminodiphenyl sulfone, 3,4′-diaminodiphenyl sulfone, 4,4′-diamino diphenyl sulfone, and combinations thereof with a guanidinium salt catalyst in the presence of a solvent, to provide a bis(phthalimide) composition comprising a residue of the catalyst and a 3,3′-bis(phthalimide) of the formula wherein the 3-substituted phthalic anhydride and the sulfone diamine convert to the bis(phthalimide) to at least 99% completion, and catalyzing polymerization of the 3,3′-bis(phthalimide) and an alkali metal salt of a dihydroxy aromatic compound of the formula
MO—Z—OM in the presence of the catalyst that catalyzes the imidization of the 3-substituted phthalic anhydride and the diamine to form the polyetherimide composition comprising a residue of the catalyst and a polyetherimide of the formula wherein in the foregoing formulae X is selected from fluoro, chloro, bromo, iodo, nitro, and combinations thereof; R is a divalent group of the formula wherein Q1 is —SO2—; M is an alkali metal; Z is an aromatic C6-24 monocyclic or polycyclic moiety optionally substituted with 1 to 6 C1-8 alkyl groups, 1 to 8 halogen atoms, and combinations thereof; and n is an integer greater than 1; wherein the polyetherimide has a Tg that is at least more than 247° C. and, wherein the polyetherimide, in molten form, has a viscosity that is the same viscosity as the initial viscosity or less than the initial viscosity after the polyetherimide is exposed to a temperature that is at least 400° C. for at least 5 minutes, the initial viscosity being the viscosity the polyetherimide has after the polyetherimide has been exposed to at least 400° C. for six minutes. |
