I work for an environmental consulting firm in the DC area. On behalf of one of our clients, we are searching for technical information regarding the corrosive effects of acid rain on automotive coatings, including the availability of test methods for evaluating potential causes of corrosion and identification of experts with knowledge in this field. Our client needs to find a person or persons who are very knowledgeable in this area to work on a project. Would you be able to point me towards organizations or individuals who could help us in this regard? Thanks so much. S.F.
There are many excellent plastisols on the market, which when applied appropriately, do not exhibit sag or drips. We strongly recommend that your reader contact his plastisol manufacturer to request a solution to his problem either in the form of process improvement suggestions or a change to a different plastisol.
The key to a no sag/drip plastisol is the use of an appropriate sag control agent incorporated into the original formulation that is stable and predictable across the entire use and cure cycle of the plastisol. Many plastisol producers use colloidal silica or organic treated clay additives and achieve a fair level of success with this challenge. To achieve the highest level of thixotropic viscosity control over all of the temperatures the plastisol encounters, my company recommends the addition of a couple of its additives at a level of about 1-3% . This must be added at the plastisol manufacturing step by the coating supplier. In short, the end user must demand a high-quality product that provides the performance he needs at a fair price. S.R.
The technical information regarding the corrosive effects of acid rain and other weathering effects on automotive coatings is generated by material suppliers to the paint industry. Traditionally, most of this information is generated by resin suppliers who supply paint manufacturers with starting formulations. These formulations are developed by subjecting their products to tests that evaluate the effects of weathering, chemical and physical exposures. The paint companies fine-tune these starting formulations to make paints that meet their customers’ specific requirements. Tests results are available in resin and paint suppliers’ technical data sheets pertaining to their products. Most of the aforementioned suppliers use standard test methods developed by ASTM (American Society for Testing and Materials). Their address is: 100 Barr Harbor Dr., West Conshohocken, PA 19428-2959. However, in some cases automobile manufacturers have their own test standards.
There are people who are experts in the field of outdoor weathering of automotive finishes. They are listed under Consultants, independent, organic finishing, on page 338 of the Products Finishing 2003 Directory and Techology Guide.