Patent · US Expired

Process for the preparation of novolak resins with low metal ion content

US5073622A · kind A · utility

48Cited by

3References

25Claims

0Family size

Assignee

Hoechst GmbH · DE

Inventors

Bernhard Wojtech · Bad Soden am Taunus, DE
Walter Niederstaetter · Eltville am Rhein, DE
Horst-Dieter Thamm · Kelkheim, DE

Key dates

Filing date	Jul 10, 1990
Grant date	Dec 17, 1991
Priority date	—
Expiry date	Jul 10, 2010

Classification

Technology area (CPC C)Chemistry; Metallurgy
CPC primaryC08G8/10
WIPO fieldMacromolecular chemistry, polymers
WIPO sectorChemistry

Abstract

The invention relates to a process for the preparation of novolak resins having a low amount of metal ions. In the process, a conventional resin in an organic solution is brought into contact with an acidic, preferably complex-forming compound which preferably is present in an aqueous phase. The resin solutions may be used in the production of photoresists.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.