DORTEC AUTODOOR TECHNOLOGY CO.LTD Dortec has 5 holding companies and about 100 categories: Panic exit device, Swing door operator, Slide door operator, Floor Spring, Glass door clamp, Door Closer, Brass … Dortec has 5 holding companies and about 100 categories: Panic exit device, Swing door operator, Slide door operator, Floor Spring, Glass door clamp, Door Closer, Brass …