Coal tar pitch and the preparation and use thereof

US5262043A · kind A · utility

Assignee

• Rutgerswerke Aktiengesellschaft · DE

Inventors

• Winfried Boenigk · Olfen, DE
• Hans-Dieter Behrens · Aachen, DE
• Hans Spengler · Halle, BE

Key dates

• Filing date: Apr 17, 1992
• Grant date: Nov 16, 1993
• Expiry date: Apr 17, 2012

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C10C1/19
• WIPO field: Basic materials chemistry
• WIPO sector: Chemistry

Abstract

An isotropic coal tar pitch having a low content of carcinogenic compounds is prepared by distilling a coal tar pitch in an evaporator having a specific evaporator surface of from 330 to 10,000 m.sup.2 /m.sup.3, at a temperature in the range of from 300.degree. to 380.degree. C., under a pressure not exceeding 1 mbar, whereby the average stay period is from 2 to 10 minutes. The isotropic pitch thus obtained contains less that 50 ppm of benzo[a]pyrene and is suitable, optionally after adding an oil, resin or other modifying agents having a low benzo[a]pyrene content, for use as binding and impregnating agent and also as protecting agent in construction materials or as varnish (painting agent).