The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 17, 1991
Filed:
Jul. 10, 1990
Applicant:
Inventors:
Bernhard Wojtech, Bad Soden am Taunus, DE;
Walter Niederstaetter, Eltville, DE;
Horst-Dieter Thamm, Eschborn, DE;
Assignee:
Hoechst Aktiengesellschaft, Frankfurt am Main, DE;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
C08F / ; C08G / ;
U.S. Cl.
CPC ...
528486 ; 528129 ; 528165 ; 528487 ; 528490 ; 528499 ;
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.