Process for the preparation of copolyphosphonates having high toughness
AssigneeBayer Aktiengesellschaft
InventorsHermann Kauth, Klaus Reinking, Dieter Freitag
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Abstract
Polyester-phosphonates, polycarbonatophosphonates and polyester-carbonatophosphonates having improved impact strength and notched impact strength as compared with melt-condensation products can be prepared in such a way that, in the first stage, oligophosphonates with hydroxyl end groups are prepared by melt-transesterification and melt-condensation and these are subjected in a second stage to a phase boundary process.
Claims10
Process for the preparation of aromatic polyester-phosphonate, polycarbonatophosphonate or polyester-carbonatophosphonate, each having a number average molecular weight of 5,000 to 200,000 and with molar phosphonate groups/(carboxylate plus carbonate groups) ratio of 95:5 to 5:95 from (1) at least one diphenol, (2) at least one phosphonic acid derivative and (3) at least one aromatic dicarboxylic acid derivative, phosgene or a mixture of both;
- wherein in a first stage, phosphonic acid diaryl ester is reacted in the melt with diphenol until an oligomeric product having a number average molecular weight of 460 to 20,000 and an OH number of 5 to 240 has been formed, and then, in a second stage, the oligomeric product is condensed by the phase boundary process with aromatic dicarboxylic acid dichloride or phosgene, or a mixture of both, until the phenolic OH content is less than 0.1% by weight relative to the resulting condensate product.
Dependencies are inferred from the claim text.