If the plasticizer is not sufficiently permanent, it may begin to exude or volatilize. As the plasticizer leaves the flexible vinyl, not only will the physical properties change, but also the plasticizer may condense on the glass in the automobile causing discoloration of the glass. This effect is known as fogging . Depending on the location of the part, it may see a very different environment. For example floor mats are removable, and are placed on the floor of the car, generally away from direct sunlight, while the dashboard often is in direct sunlight, so it will be exposed to much higher temperatures than floor mats.
All automobile manufacturers have specific fogging and other permanence testing specifications.
In some cases, polymeric plasticizers blends must be used to pass the most severe temperature requirements. Copyright 2000 Eastman Chemical Company. All rights reserved. Please see our Legal Information.