Grantee Research Project Results

Final Report: Environmentally-benign Polytetrafluoroethylene (PTFE) Coatings for Mold Release

EPA Contract Number: EPD13048
Title: Environmentally-benign Polytetrafluoroethylene (PTFE) Coatings for Mold Release
Investigators: O’Shaughnessy, W. Shannan
Small Business: GVD Corporation
EPA Contact: Richards, April
Phase: II
Project Period: July 29, 2013 through July 28, 2015 (Extended to November 28, 2016)
Project Amount: $298,009
RFA: Small Business Innovation Research (SBIR) - Phase II (2013) Recipients Lists
Research Category: SBIR - Innovation in Manufacturing , Small Business Innovation Research (SBIR)

Description:

GVD proposed to develop high performance, VOC-free and PFOA-free, non-stick mold release coatings based on its novel PTFE (polytetrafluoroethylene) fluoropolymer technology. Most commercial mold release agents make use of organic solvents that vaporize during drying, creating a significant air quality impact.  Even water-based formulations often require the use of fluorinated surfactant additives to stay suspended in the liquid. These surfactants such as PFOA (perfluorooctanoic acid) have been shown to be exceptionally pervasive in the environment, and are biopersistent and carcinogenic.  Drying and curing processes of wet applied release agents are also energy intensive, requiring consumption of fossil fuels and the attendant emission of greenhouse gases. The environmental problems associated with these mold release agents and tighter regulations imposed on their use are generating urgency among manufacturers to identify green alternative release agents with the same level of performance. GVD’s green polytetrafluoroethylene (PTFE) coatings offer such an alternative. PTFE presents an unparalleled combination of low surface energy (anti-stick), chemical resistance, and thermal stability. GVD produces thin, conformal, environmentally-benign PTFE coatings at low temperature via the innovative initiated Chemical Vapor Deposition (iCVD) process. In this solvent-free process, GVD creates the pure PTFE fluoropolymer from reactive precursor vapors and deposits the PTFE as a uniform coating at the same time. Using iCVD, GVD can optimize PTFE’s surface energy, adhesion, and durability during deposition. GVD’s iCVD deposition process has zero hazardous emissions. There are a wide variety of markets and applications for GVD’s mold release coating, including seals and gaskets, foam, automotive parts, composite part molding, and medical products. 

In Phase I, GVD achieved the goals on improved adhesion and durability of PTFE coatings for mold release applications. Bench scale testing showed that changes to the PTFE coating recipe improved coating adhesion with even greater improvement upon addition of an adhesion promoter. Initial molding tests with uncured molding materials, a challenging condition, demonstrated that the advances made during Phase I resulted in significant improvements to mold release durability. GVD’s coatings also outperformed wet-applied mold release coatings in the molding test.

In Phase II, GVD demonstrated:

• Successful implementation of GVD’s release coating in industry
• Comparable performance of GVD’s coating to other release coatings used in industry, which are hazardous to the environment, by in-situ testing
• Expansion into the tire market, bringing GVD closer to mass commercialization of GVDs coating and elimination of environmentally hazardous release coatings for tire molds, as well as other mold applications
• Improved performance of GVD’s mold release coating with a pre-cleaning procedure that is not detrimental to the mold, yet provides a clean surface for the coating to be applied and improves coating performance

Using the coating recipe established in Phase I, GVD has launched a production scale coating that does not require additional adhesion promotors or annealing. This reduces time and money for the coating process while still producing a quality mold release coating. During Phase II, GVD expanded its market to various major tire manufacturers. This gave an increased understanding of the tire mold market’s needs and preference for a mold release coating. It also opened the doors to further improvements for GVD’s coating, such as the most effective cleaning process prior to applying GVD’s mold release coating to a surface. With this understanding of the tire manufacturing market, GVD was able to streamline its process to accommodate larger tire molds by modifications to its coating deposition chambers.

During this Phase II, GVD made a number of accomplishments towards its goal of increasing the environmental impact of GVD’s VOC-free mold release coating by improvements in both performance and distribution:

• Bench scale mold release testing shows release force is decreased when using GVD’s mold release coating compared to not using a mold release coating.
• Bench scale mold release testing showed comparable results for release force when comparing GVD’s coating to a commercially used spray-on release coating used in industry.
• GVD has coated a variety of tire molds for multiple major tire manufacturers.
• Reports from different tire plants have shown comparable or improved performance to industrial release coatings, with the added benefit of:
  • Being environmentally safe
  • Safe for the operators working in the plants
  • Producing higher quality tires, reducing repair time
  • Reducing rubber stuck-in molds, requiring downtime for cleaning
  • Improved flow of rubber into small features, reducing repair time for visual defects

Based on the technology developments enabled by this SBIR grant, GVD plans to continue the expansion of our environmentally benign mold release technology. Initial efforts will maintain our focus within the tire manufacturing industry, working to further increase our market penetration and also expand into heavy truck applications. Follow-on work will then target other compression molded rubber applications. Further technical work will also assess the applicability of our mold release technology beyond rubber compression molding, looking at both other molded product chemistries and molding techniques.

SBIR Phase I:

Environmentally-Benign Polytetrafluoroethylene (PTEE) Coating for Mold Release  | Final Report