UV curing in the automotive industry

Applying a UV curable hardcoat onto polycarbonate plastic lenses provides improved scratch and chip resistance. The thermal process that UV curing replaces takes up to three hours, requires lenses to be heat-annealed, cooled, coated with a primer, baked, cooled, top-coated, baked and cooled. The UV process takes less than 10 minutes, reducing parts-in-process, allowing quicker part changes, and lowering energy costs.

UV technology offers fast processing with improved performance for reflector housings for automotive lighting. UV light is used to pre-treat the housing surface improving adhesion of the UV-curable primer. The primer provides an extremely smooth surface for the subsequent vacuum deposition of aluminum and a superior reflective surface. The reflector is then top-coated with a protective UV-cured clearcoat to preserve the mirror-like finish of the soft aluminum. The thermal process that UV replaces takes a total of three hours. The UV process decreases parts inventory and space, and energy costs, while improving yields and product performance.

Acrylic tail lenses are first decorated with a UV-cured silk-screen coating. Then a UV clearcoat is applied to protect the decoration while providing a uniform, high-gloss finish. The UV clearcoat also provides superior abrasion resistance and gloss retention compared to urethane and acrylic clearcoats, but the UV coating is flexible enough to match the thermal expansion rate of the coatings beneath it, which the brittle, thermal silicones could not. This flexibility prevents cracking of the clearcoat during subsequent cyclic thermal testing.

UV coatings provide abrasion and scratch resistant clear coatings on a variety of exterior body components including facias, fenders, spoilers, and body side molding. For example, exterior body side moldings are typically extruded from pigmented vinyl. The materials are very inexpensive and efficient to form, but tend to yellow and stain in the field. To overcome these deficiencies, a UV-cured clearcoat is applied to substantially improve product performance without significantly increasing the process time.
In addition, UV inks provide black-out around windshield edges and logos on glass windows, and UV adhesives are used on exterior side mirrors. UV metalized primers and topcoats are used on PVD plastic parts providing an environmentally friendly process and recyclable parts.

Today’s cars and trucks are incorporating more electronics with the proliferation of infotainment, safety systems, hybrid vehicles, and eventually self-driving capability. UV curing plays a vital role to provide increased durability and reliability for automotive electronic components so they can withstand challenging exposure to moisture, contaminants, vibration, extreme temperatures, and chemicals. Common UV curing applications include electrical connection potting compounds, conformal coatings and solder masks on PCBs, component marking, sealing and gaskets on electronic housings among others. Electronic component manufacturers turn to UV curing processes to increase production rates, improve reliability, and reduce waste.

Gaskets fill intricate channels to seal out dirt, air, moisture, and noise on automotive components such as door handles, electronics and sensors, filters, and lighting assemblies. UV-curable solid and form-in-place (FIP) or cure-in-place (CIP) silicone gaskets cure on demand to significantly reduce waste and increase production rates for sound and vibration dampening, moisture and chemical protection, and air and liquid sealing for automotive parts and assemblies.

UV cured materials provide temperature, chemical and moisture resistance for components that must withstand the harsh automotive under-hood environment. Examples of UV applications for under-hood components include electrical connection potting compounds, conformal coatings and solder masks on PCBs, pigmented coatings on oil filter housings and airbag cartridges, UV cured gaskets, battery labels, and component marking inks.

UV curing is used on interior parts such as consoles, door components, dashboard instrument panels and displays, touch screens, and control buttons and knobs. UV coatings provide durability, scratch resistance, and a range of aesthetics including soft-touch, gloss and matte finishes with excellent adhesion on plastic parts.
Waterborne UV-curable clearcoat provides excellent mar and chemical resistance as a very low gloss coating on flexible vinyl-wrapped parts. The UV coating provides higher performance than solvent-borne and waterborne thermally cured coatings, with a very low VOC content.
In-mold films with latent UV activation are also being used to decorate interior automotive trim. These in-mold films are used to decorate the trim in high pressure injection molding processes. Post mold, the parts run through a UV curing process to activate the high performance properties common to all UV coatings. This process is commonly used for consoles and other interior parts, especially on high-touch surfaces that require high abrasion resistance such as door trim, consoles, and radio surrounds. Finishes available are piano black, carbon fiber look, and more recently, soft touch films are available. UV curing provides improved throughput and aesthetics compared to post-paint coating.
Markings on instrument panels, gauges, and control knobs and buttons use UV-curable inks because they provide improved durability with reduced VOCs compared to traditional inks. Chrome look plastic parts are using UV cured primers and topcoats for PVD processes which are environmentally friendly and provide durability and recyclability of interior parts such as door handles, brand badges, and consoles.

UV-curable coatings provide durable, abrasion resistant coatings for plastic wheel covers and metal wheels. UV-curable coating used in conjunction with standard automotive powder coatings and serves as the primer for accepting PVD. The UV process reduces processing and cool-down time, space requirements, as well as energy costs.

 Read more about how UV coatings provide a chrome plated look for aluminum wheels.