Safety and Sustainability for Automotive Adhesion Promoters
Sustainability is a topic that consumers have top of mind when it comes to making decisions about purchasing automobiles. To this end, automotive manufacturers have placed a heavier focus on creating vehicles that are lighter in weight, have greater fuel efficiency, or have electric engines with the aim of reducing carbon emissions into the environment.
The process of manufacturing these vehicles, however, remains a global area of focus for improvement regarding safety and sustainability. Especially within automotive coating processes, for example, assembly lines still utilize significant amounts of products that contain hazardous air pollutants (HAPs) and toxins for workers and the environment.
Concerns Within Coating Processes for Automotive Plastics
Thermoplastic olefins (TPOs) and polypropylene are plastics commonly used on front and rear bumpers, trim, instrument panels, and wheel well liners. These plastics are notorious for their low surface energy and resultant difficulty getting basecoats, such as paints, to adhere onto. Thus, primers are necessary to ensure adequate adhesion between plastic automotive parts and paint basecoats.
Traditionally, these primers have been formulated with solvents and additives that contain high amounts of VOCs, HAPs, halogens, and APEOs. Exposure to VOCs and HAPs, as well as halogens like chlorine, causes respiratory harm to auto workers. APEOs are still being investigated for their impact on human health. Still, they are toxic to aquatic organisms and may accumulate in the environment when cars and parts are scrapped or recycled. Thus, safe and sustainable primer options must be used to improve both safety and sustainability in automotive manufacturing processes.
Eastman’s Sustainable Adhesion Promoters
Eastman’s Advantis™ 510W is the latest advancement in safe and sustainable chemistry for adhesion promoters, as it is APEO-free, chlorine-free, VOC-compliant, and water based. Highly compatible with other waterborne resins used in coating and primer formulations, it is perfect for use as a blend-in, adhesion-promoting resin within waterborne primer and paint basecoat formulations. Formulations using Advantis™ 510W have superior adhesion onto automotive bumpers and plastic parts for automotive interiors made of thermoplastic, polyolefin-based plastics like TPO or PP.
Advantis™ 510W also has utility beyond TPO and PP substrates and can even be used to promote adhesion onto non-olefin substrates like nylon, polyphenylene ether, and ABS. While many formulators use Advantis™ 510W as a blend-in adhesion promoter, it can also be diluted and used as a wash primer.
CP 377W is Eastman’s water-based chlorinated polyolefin adhesion promoter that is APEO-free. It is typically used within the automotive industry as an additive to provide primers and basecoat paints with excellent adhesion onto TPO and PP substrates.
If the presence of chlorine is acceptable, using CP 377W will provide superb resistance to humidity in a paint, coating, or primer system. CP 377W also has excellent compatibility with a wide range of waterborne resins in coating and primer formulations, including those that are amine-neutralizable.
AP-550-1 is Eastman’s solvent-based, chlorine-free polyolefin adhesion promoter that is typically used as a primer in automotive applications. It is also APEO-free and provides outstanding adhesion of paints and coatings to TPO and PP substrates.
If there are no concerns working with organic solvents, namely xylene or aromatic 100, AP-550-1 is a great choice as a primer for working with two-component systems, such as two-part urethane coatings. It also performs well with many melamine-cured systems and has outstanding resistance to gasoline exposure. Formulators who may be working with another adhesion promoter system can benefit from adding AP-550-1 to boost gasoline resistance.
Eastman’s adhesion promoters are instrumental in creating a positive impact on safety and sustainability for both automotive work environments and the global environment. The regulatory, safety, and performance advantages for each grade detailed in the preceding sections are summarized below.