Modern MDF door skin
Materials of interior doors construction : Modern MDF Door Skin
Quote from Article entitled Materials of interior doors construction:
Interior doors PVC are bought not only for business centers, shops, places of mass visits, but also for country houses, apartments, staircases of apartment buildings. These doors are so popular because of their increased sound and heat insulation, easy opening and simplicity of upkeep.
The full version of the article can be found here.