Recorded Tuesday, April 11- Presented by RTP Company
UV resistance in thermoplastic compounds refers to the plastic’s ability to resist degradation due to Ultraviolet radiation absorption. Without UV resistant additives, thermoplastics can change in appearance and structure when exposed to ultraviolet light, causing brittleness, cracks, color shifts, or warping over time. RTP Company offers a variety of solutions to help ensure your thermoplastic application is protected against the damage caused by ultraviolet light, thereby increasing the longevity and maintaining the desired aesthetics for your application.
Join RTP Company color experts as they discuss the science behind UV resistance for thermoplastic compounds, including how they can benefit your application, and what to keep in mind during the design phase. This webinar is for engineers, molders, sales representatives, and purchasers who want to better understand the mechanics of ultraviolet light and the importance of resin selection in maintaining UV resistance for your application.
Presented by Tim Duncan, RTP Company Global Color Technology Manager, and Anna Kreofsky, RTP Company Color Engineer, this 40-minute webinar will cover the following topics:
- Brief introduction to the RTP Company Color Division and how you can have Your Color – Your Way
- What is UV degradation and how to prevent it from occurring
- Materials testing
- Case studies
- Question and answer session
Register now to learn more about UV Resistant Thermoplastic Compounds and how RTP Company can provide design flexibility, global manufacturing consistency, and technical expertise for your application.
Download the slides (for Prospector Members only) | Webinar Transcript
Tim: So let’s start with, what’s weathering of plastics? Weathering means what happens to your part when it’s exposed to Mother Nature. Primarily, we’re talking about solar radiation, extremes in temperature whether it’s in the frozen tundra of the North or the desert southwest, and rain and other forms of precipitation and how that can influence behavior. Now, over time, exposure to sunlight and even artificial forms of UV radiation, will degrade plastics. Performance depends on the choices we make that entire polymer matrix everything coming together working as a system. Now weathering includes a variation in temperature precipitation and sunlight intensity, we’re gonna focus primarily on the ultraviolet region of the electromagnetic spectrum today. Here’s an example of that electromagnetic spectrum. We’re all obviously aware of the visible light. The ultraviolet is the shorter energy wavelengths right before the visible light and in some cases, it bleeds a little bit into the visible blue and violet regions of that spectrum.
We’re going to focus a little more on the three basic types of UV light that we encounter when we’re discussing stabilization of polymers. They’re broken down into wavelengths. We’ll begin with UV-A which is the longest of the wavelengths of the UV radiation, and this is related to tanning and premature skin aging in our day to day lives but it also contributes to the degradation of polymers. The UV-B, that’s slightly shorter more energized and the most damaging covers the range from 290 nanometers to 315 nanometers. Prolonged exposure would cause a sunburn to those of us not wearing appropriate protection. As I said, fortunately, much of this is absorbed by the ozone layer, but what does get through is the most damaging and the most sensitive to polymers. Now, UV-C gets mentioned from time to time in our industry. Many times it’s in medical or water purification used for germicidal application. Some of you may have an electric toothbrush that you take the tip off and you put in your UV sterilization overnight, these are those types of wavelengths. And while shorter still and less influence on polymers, they still contribute to yellowing and some degradation.
So what are the results of this exposure? Well, as the polymer begins to receive this light energy, it attacks and is absorbed by various chemical groups within the polymer actually ripping the chains apart. This process damages the ability of the material to perform as intended and this reduction of polymer change only further exacerbates the problem. It lowers the molecular weight in this irreversible chemical reaction. That loss of molecular weight affects our mechanical properties, the material is no longer as elastic as it was before. Strength is reduced, impact resistance is reduced. And, of course, it changes in appearance, yellowing for a natural polymer on uncolored polymer is very, very typical. But with colored materials, you may see the colors begin to fade, you may see them become darker or more yellow or they may completely change in hue. Cracking and crazing and loss of polymer at the surface is dramatic. Reducing the gloss of the material, we no longer have that shiny new appearance. And in severe cases, you actually see the chalking and the white residue. This white residue is dramatically degraded polymer on the surface. As these properties begin to fail, we see changes in dimension and warping in the materials.
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