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A Guide To UV-Resistant Plastics

When UV Resistance Matters

UV rays can significantly damage everything from your skin to items you store outside. In plastics, long-term exposure to UV radiation can lead to discoloration, reduced impact and tensile strength, and overall deformation of the material. If you're choosing a plastic material for an outdoor application, you will want to know that the material is UV resistant. UV resistance ratings are an excellent tool for choosing plastic that will stand up well under long-term exposure to the sun. Here is a closer look at UV resistance ratings, the best plastics for UV resistance, and the applications and industries where these materials make sense.

Understanding UV Resistance Ratings

No matter how durable a material is, it cannot be fully UV resistant. Many plastics, however, have additives that increase their UV resistance. When rating plastics for UV resistance, some manufacturers rate them in years. This rating means that the plastic should have minimal degradation when exposed to UV radiation for the number of rated years. That said, some areas of the world have more intense UV radiation than others, so this is not an exact number. Generally, the more years the product is rated, the more UV resistant it is.

Since no one can guarantee a certain number of years of UV resistance, some manufacturers use a simpler rating method of low, moderate, and high. This rating system is a bit clearer, helping you choose a plastic that fits your needs and budget.

Top UV Resistant Plastics

To make plastics UV resistant, they must add additives or stabilizers to the basic plastic material. For this reason, the top thermoplastics to consider when concerned about UV resistance are these:

1. Acrylic

Acrylic is one of the top options. Over ten years, it can have as little as 3% degradation, depending on the application. This resistance and its natural transparency make it a popular choice for signage, displays, and light fixtures. It's also often used as a replacement for glass.

2. High-Density Polyethylene

HDPE is a durable plastic when hardened, but its nature makes it easy to melt and mold into unique shapes. It's a popular choice for playground equipment because it doesn't create sharp edges when it breaks. It's also resistant to alcohols, bases, and acids and won't accept graffiti easily. It holds its color well when used outdoors as well.

3. Polycarbonate

Polycarbonate is another good option for windows and signage with similar transparency to acrylic. It's also strong, making it a good choice for safety goggles and shields. It's a more costly choice, but it is the right choice when durability and UV resistance are both necessary.

4. Polyamide-Imide (PAI)

Known more commonly as Torlon, This thermoplastic combines nylon and polyimide to create a strong, chemically resistant plastic that is strong and stiff with a high melting point. This material is often used in outdoor piping, fittings, seals, and gaskets where impact and crack resistance are as important as UV resistance.

5. PTFE

PTFE resists damage from UV rays well. This fluoropolymer is made from a combination of carbon and fluorine. It also has low friction and is quite flexible. This material is often used for bearings, non-stick surfaces, and gaskets, many of which are used in outdoor applications.

6. Polyetherimide

Polyetherimide, or PEI, is a common choice for industrial and automotive applications. Not only is it highly UV resistant, but it's also flexible, rigid, and has a high deflection temperature. It's versatile because it can be transparent or translucent, depending on how it's made.

Applications and Industries

UV resistance is most important when choosing plastics for outdoor applications. Some common applications that require UV-resistant plastics include:

  • Outdoor furnishing
  • Outdoor fixtures
  • Playground equipment
  • Outdoor signage
  • Windows and window glazing
  • Automotive, aircraft, and watercraft components
  • Outdoor lighting
  • Solar panels and infrastructure
  • Farm machinery
  • Scientific instruments used outdoors

There are applications in a wide range of industries, including transportation, agriculture, construction, science, recreation, and goods for homes. Any enterprise that spends a significant amount of time outdoors exposed to the elements and that uses plastic needs those plastics to be UV resistant.

Choosing the Right UV-Resistant Plastics

When choosing UV-resistant plastics, don't just look at the UV rating. Other factors to consider include:

  1. Impact Resistance – This measures a material's ability to withstand the impact of a shock or forceful action. Impact resistance is vital for safety equipment used outdoors, such as windshields, or items that may be handled roughly, like outdoor toys.
  2. Strength – Strength includes tensile, compressive, and flexural strength. All are important, depending on the application. Make sure the plastic you choose is strong enough for the application.
  3. Transparency – Some UV-resistant plastics have good optical clarity. This is an important feature to look for when making windshields or windows.
  4. Weather Resistance – UV light is just one aspect of the weather that can impact plastics. Outdoor items must also be resistant to temperature, moisture, and wind changes.
  5. Chemical Resistance – If the material is exposed to oils, solvents, or other chemicals, choose a plastic with high chemical and UV resistance.

Maintenance and Care Tips to Maintain UV Resistance

How you care for your plastics will impact how well they resist damage from UV light. Here are some tips for ensuring your plastic products maintain their UV resistance as long as possible:

  • Avoid using products that could dull the plastic finish, such as alcohol or solvents, when cleaning.
  • Protect the plastics from heat damage, such as setting hot items on outdoor furniture.
  • Routinely hose off the items to remove surface dirt.
  • Use cleaners designed for the type of plastic you have.
  • Avoid activities that could scratch the surface of the plastic.

If you are in the market for UV-resistant plastic materials, regardless of the application, Piedmont Plastics can help. Reach out to our team to discuss the various plastic options, their UV resistance rating, and which one will fit your application best.