Process for the preparation of naphthalenesulfonic acid/formaldehyde condensates having a low free formaldehyde content
AssigneeChemie Linz Gesellschaft m.b.H.
InventorsEmmerich Jager, Walter Lechner
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Abstract
Process for the preparation of naphthalenesulfonic acid/formaldehyde condensates having a low content of free formaldehyde, in which the condensation products of naphthalenesulfonic acid and formaldehyde obtained after the condensation, are brought to a pH of greater than 11.5 at a temperature of not less than 80.degree. C. immediately after the condensation, and are kept under these conditions until the desired formaldehyde content is reached. The resins are preferably used as plasticizers for building materials, for example as concrete plasticizers.
Claims5
In a process for the preparation of naphthalenesulfonic acid-formaldehyde condensates having a low content of free formaldehyde, the improvement which comprises bringing the condensation product of naphthalenesulfonic acid and formaldehyde to a pH of greater than 11.5 at not less than 80.degree. C. immediately after the condensation, and keeping it at this temperature until the desired low content of free formaldehyde is reached and then bringing the napthalenesulfonic acid-formaldehyde condensates having a low content of free formaldehyde to a pH of 7 to 9, after the desired low content of free formaldehyde is reached.
Dependencies are inferred from the claim text.