We all know that the right paint can make a product or item of personal property more aesthetically pleasing and desirable. Adding a fresh coat of paint to a house or car can raise its value by thousands of dollars. First impressions, often the most important impressions, are based largely on exterior colour and texture.
But many paints and coatings have benefits that are more than skin deep, going beyond visual appeal. Paints and coatings consist of three parts:
• A thinner which gives them a liquid consistency
• A binder which binds the pigment particles and adheres to surfaces
• Additives which provide additional properties.
Depending on these elements, paints and coatings can serve a wide variety of purposes.
Flame Retardant Paints
Some paints and coatings are flame-retardant, meaning they have properties that let them absorb heat and reduce heat transfer while forming insulation pockets between the surface and the flame, melting into a glasslike consistency or producing nonflammable gases.
Other Paints and Coatings
Other benefits and applications abound. Zinc primer coatings conduct electricity, providing a high degree of cathodic protection. Aluminium coatings are used to reflect light or retain heat. Powder-coated surfaces are extremely resistant to dents. The list goes on and on.
Mechanical Properties of Paint
But one thing all these paints and coatings have in common is a need for resistance to impact. Accidents happen. Vacuum cleaner handles can scrape against a painted wall. And of course, shopping carts are prone to bumping car fenders and doors. But these types of impact accidents do not have to lead to chips, cracks, dents and dings. This is where proper impact testing of paints and coatings is so important.
Impact testing Equipment for Paints
Today’s impact testing instruments cannot only tell us how paints and coatings can stand up to varying degrees of impact, but also how they withstand impact under a variety of environmental conditions such as sub-ambient winter cold and summer heat and humidity. In the past, unsophisticated “drop the ball on the painted plaque” tests produced questionable results. Although inexpensive (or perhaps because they are inexpensive), these types of testing were subjective and inefficient.
Case Study: Red Spot Paint & Varnish Co.
Today, paint and coating manufacturers are turning to more sophisticated and reliable impact testing equipment. One such company is Red Spot Paint & Varnish Co., a leader in the production of ecologically sound, high performance coatings for automotive plastics, as well as coatings for plastics in sports and consumer products. Headquartered in Evansville, Indiana, Red Spot prides itself on its new product development and related R & D. So it shouldn’t be a surprise that they use the most advanced impact testing equipment.
According to Red Spot’s Lab Manager, Jeff Adler, “We’ve found that the Dynatup® impact testing instrument from Instron® gives us the accuracy and repeatability we need. Unlike equipment that we’ve used in the past, the Dynatup provides us with a computer analysis of the impact test, including the velocity and total energy of each impact event.”
Instron testing equipment is used to test the mechanical properties and performance of various materials, components and structures in a wide array of environments. Paints and coatings is just one of the many materials Instron systems test.
At Red Spot, Instron’s Dynatup machine allows the manufacturer to efficiently perform hundreds of impact tests. Red Spot is able to see how their paints and coatings perform when bonded to a variety of different plastics and when used under a range of different conditions. In so doing, they are able to identify what raw materials work to decrease the brittleness of unpainted plastics, and thus which materials work best in their paint formulas.
An instrumented impact testing instrument, the Dynatup tests impact properties of polymers, metals, composites as well as the paints and coatings used on these products. Unlike most testers, Instron’s Dynatup captures, plots and analyzes the entire impact event. This means the system is able to determine important data such as the ductile-to-brittle transition point, ductility, incipient damage, max load and absorbed energy.
Ensuring Product Quality
The Dynatup helps Red Spot meet the most stringent industry standards. “We perform a test method per GM9904P,” explains Adler, “which provides us with information on the traits of a given coated plastic and the reasons for failure, whether it be ductile or brittle or whether it is unable to stand up to extremes in temperature and environment. For Ford Motor Co., we perform tests to meet ASTM D3763, and we see a wide variety of impact retention changes. I have seen impact retention as low as 10% and as high as 200%.”
Adler knows the dangers inherent to not using the most reliable impact testing equipment. “Because our customers count on us to predict how coatings perform, a lot is riding on our impact testing. With the Instron testers, we can be certain that our products meet the required specifications before they go out the door.”
Thanks to today’s impact testing machines, companies like Red Spot have a greater understanding of the real-world properties and characteristics of the paints and coatings they manufacture. And vacuum cleaner handles, shopping carts, air-borne pebbles and the like can have much less impact on the painted and coated products we use everyday.