John Frijns has been appointed as managing director of EFKA Additives based in the Netherlands, effective Jan. 1. He takes over this role from Wolfgang Habel, who is retiring after having led the company for 20 years.      Mr. Frijns will continue his present roles as segment representative, coatings effects and country manager, Benelux for Ciba Specialty Chemicals. He has been with Ciba for more than 20 years, and has played an active role in its international coatings business since 1984.  ...