VINYL PAINTS AND COATINGS

  Maintenance and marine coatings based on vinyl resins (PVC) have a long track record of proven performance for the protection of valuable assets. Coatings systems formulated from these resins are noted for their outstanding chemical, corrosion, and water resistance. In addition, these systems are single-component, recoatable, and can be applied at temperatures ranging from below freezing (0 F) to tropical (100 F).

  Vinyl Coatings technology was pioneered after World War II to control the corrosion on steel dam gates along the Mississippi River . Previously, oil-based technology had resulted in paints that performed well on atmospheric exposed dams, but failed quickly in the areas immersed in water. By the mid-1950s, their proven durability had made vinyl coatings the industry standard for marine applications.  Vinyl coating systems were used on virtually every water lock, dam, dock, barge, ship, hydropower and maintenance facility that requires a tough durable anticorrosive coating. However, within the past few decades increasingly stringent air-quality standards and environmental regulations curtailed the use of the solvents used in these systems. Commonly used solvents for vinyl coatings were 2-butanone (MEK) and toluene. Both of these solvents are classified as Volatile Organic Compounds (VOC’s).

  Due to their durability, vinyl polymeric (PVC) coatings have been used to protect substrates which are exposed to harsh environments. Unfortunately, the solubility of poly (vinyl chloride) resins (PVC) in organic solvents is rather limiting. Those solvent systems that do solvate PVC resins are often regulated as a volatile organic compound (VOC) and hazardous air pollutant (HAPS), which greatly complicates the pragmatic aspects of commercializing such resins. Some solvents have been exempted from VOC regulations, but the solubility of PVC in those VOC-exempt solvents is low and/or there are additional complications caused by such solvents. Acetone is one of the few VOC-exempt solvents that will solvate PVC. However, if one attempts to coat a PVC resin from an acetone solution, the acetone evaporates too quickly. PVC resins deposited from such solutions do not cure properly, dry too quickly, will not form a uniform film, and the resulting coatings do not provide the desired level of chemical protection. Additionally, if the coating is sprayed the acetone evaporates in the midst of the spraying process which results in a “spidering” of the resin during coating.

  Tarksol, Inc., Rochester , New York developed, with US Patent pending a unique solvent system that the PVC resins may be solubilized from a new inexpensive natural solvent, produced from plant life and a VOC exempt solvent. The resulting PVC Paint or coatings are less than 100 grams/liter VOC’s and utilize the same Dow Chemical PVC Resins used years ago. The resulting PVC paint can be applied by spray, brush or roller, dries in 10-15 min., recoat immediately or years later, and does pass the Army Corp of Engineers Unified Facilities Guide Specifications UFGS-09965A test for water submersion. The Products are marketed by Biocoatings LLC, Ft Lauderdale, FL as Biocoatings Vinyl Paints and Vinyl Coatings.

  The PVC paints and coatings produced offer the following properties:

Film flexibility

Water resistance

Excellent adhesion to metal

Chemical resistance

Recoat

Vinyl based coating systems have had an outstanding track record in the marine coatings and other industries. These tough durable coatings are the ideal solution many ship, lock, bridge, crane, barge, and container applications. With the development of new environmentally friendly and VOC compliant solvents, vinyl coating system systems can once again be used in challenging marine and industrial applications. It is expected that vinyl paints will reemerge from environmental retirement as a premium metal coating solution. 

  Case Histories of Vinyl (PVC) Paints and Coatings

The outstanding performance of vinyl coatings for corrosion prevention of structural steel was built on the use of multicoat systems. Applied by atomized air spray, film thickness of 1-1.5 mils (25-40 microns) are obtained with each coat. Two or more coats are usually specified to develop sufficient film thickness. Successive coats can be applied in intervals as short as two hours at temperatures of 70 F (21 C). Lower temperatures of course, will require longer intervals. Complete solvent release is not necessary between coats, although the completed job must be allowed to dry thoroughly before being put into service.

The US Army Corps of Engineers- was one of the earlier users to make widespread use of vinyl coating systems. Vinyl coatings were applied to a series of locks and flood gates along the Mississippi River with excellent results.

              Examples

1. A tainter gate at the lock and dam system on the Mississippi River at Hannibal , MO was painted in 1950; a small amount of touch-up was done once or twice, but most of the area retained the original vinyl paint from 1950 to 1981. The gate was inspected in October of 1981, and the vinyl paint was found to be still intact. The vinyl coated interior of the gate, which is not exposed to the same abrasive action from river debris as the exterior, was determined to be in such good condition that it was returned to service without repairing. The exterior of the tainter gate was grit blasted and recoated with the Corp of Engineers multi-coat vinyl system using a vinyl resin as the vehicle for the primer.

Steel Structure Painting Council (SSPC)-a service test of the best available coating system was set up in 1950 on the interior of a one million gallon municipal water tank at Ambridge , PA.   A twenty – five year inspection was conducted in 1975; the outstanding performance of vinyl paint led to the development of SSPC Paint No. 9. The formulation approach was widely adopted throughout industry. A number of state highway specifications reflect this idea of combining the adhesion characteristics of vinyl resin to accommodate a range of conditions with one paint (vinyl).

The Bureau of Reclamation- has many histories on file for the vinyl systems it has used for many years on the flood control dams in the Western states. The Bureau of Reclamation specifications VR-3 and VR-6 rely on the vinyl resin paints for adhesion directly to steel.

St Lawrence Seaway-Eisenhower Lock-In 1959, a vinyl paint system was used on the miter gate of the Eisenhower Lock on the St. Lawrence Seaway ; in 1982 the steel was still protected. An interesting sidelight to this case history is that when it was time to recoat the gate, the entire gate structure was roofed over to permit work to proceed in the winter when the Seaway was closed because of the heavy ice formation. Temperatures below 50 F (10 C) present no problems with application of vinyl systems since there is no curing mechanism involved. Drying time is longer since evaporation rates of solvents decrease with the decrease in temperature. Several weeks may be required for through drying at these low temperatures, but good adhesion will develop once all the solvent has left the film. In fact, when maintenance schedules required that structures be painted and returned to service before river traffic returned, vinyl paints have been applied at temperatures as low as 0 F (-18C).

US Air Force- The US Air Force experience started with the firing of Delta rockets in the 1960’s at Cape Canaveral , FL , reveals that another aspect of vinyl versatility. At these missile test sites, vinyl topcoats were applied over zinc-rich primers to protect the zinc from acid attack from rocket engine fuel.

Maine DOT- In 1983, a survey conducted by Maine DOT of the specifications in use by state highway departments determined that twenty-five states were specifying zinc-rich primers, usually of the inorganic type, with vinyl topcoats. For new construction, these systems were specified regularly for use in aggressive industrial and marine environments.

US Navy Bureau of Ships (The Present NAVSEA)- PVB (polyvinyl butyral was used in World War II development work sponsored initially by the National Defense Research Council and later by the US Navy Bureau of Ships ( the present NAVSEA). The objective was to develop a metal conditioner for shipyard use that would protect newly prepared steel surfaces from rusting and improve adhesion of subsequent coats of paint. These have been commonly referred to as a wash primer. Because vinyls will adhere to vinyls, topcoats based on vinyl resins adhere well to the PVB wash primer.  

Jacksonville , Florida- Several bridges in the Jacksonville area were painted with Vinyl paint and these structures were finished in 1987.

Why did Vinyl Paints and Coatings Leave the Market?

Vinyl paints and coatings came off the market in the 1980’s, due to the only solvents available were HAPS (Hazardous Air Pollutants) and VOC’s (Volatile Organic Compounds). Due to commercial solvent availability, the vinyl paints and coatings were no longer available that met Federal and state regulations. With the development of the new Tarksol solvent technology, it is possible to reintroduce the same vinyl resin paints in the non-HAPS and non-VOC solvent Tarksol One Plus Green Solvent.

Bibliography

Bureau of Reclamation Specifications: M-54 VR-3 Vinyl Resin Paint, April 13, 1984 : M-55 VR-6 Vinyl Resin Paint, April 13, 9184

K. Doolittle, “Case History Report on Long Term Coatings Performance,” Materials Performance, November, 1963, National Association of Corrosion Engineers, Houston , TX .

D.H. Gelfer and K.B. Taylor, “Vinyl Coatings for Resistance to Atmospheric Corrosion,” Materials Performance” December 1977, (NACE Publication 6H177) National Association of Corrosion Engineers, Houston , TX .

R.J. Martell, “Vinyl Paints and Systems,” Proceedings: 3^rd World Congress – Coating Systems for Bridges and Steel Structures, November 2-3, 1983 .

C.N. Merriam, T. Ginsberg, and L.G. Kaufman, “Heavy Duty Vinyl Systems,” Australian OCCA Journal, January-February, 1978.

D.S. Leyland, A Survey of Coatings & Systems for The State Highway Departments, Materials and Research Division Technical Paper 83-10, State of Maine Department of Transportation, Materials and Research Division. Reprint in Journal of Protective Coatings & Linings, May, 1985.

Charles G. Munger, Corrosion Protection by Protective Coatings, National Association of Corrosion Engineers, Houston , TX , 1984.

Painting Hydraulic Structures and Appurtenant Works, Civil Works Construction Guide Specification CW-09940, August, 1981.

J.J. Stevens and D.M. Berger, “Vinyl Coatings for Mississippi River Locks and Dams,” Materials Performance, March, 1974.

Richard R. Ramsey, “ Florida DOT Performance Specifications for Inorganic Zinc Rich, Journal of Protective Coatings & Linings, May, 1985.

‘Vinyls Are Back in the News”- But then They Never Really Left,”  American Painting Contractor, September, 1974.

Steel Structures Painting Manual, Vol. 2, Systems and Specifications, Fourth Edition, 1985, Steel Structures Painting Council, Pittsburgh , PA.

                                              VINYL SPECIFICATIONS