The short answer
For outdoor parts, start with resins that resist UV on their own: ASA, acrylic and PVDF. Otherwise use a UV-stabilized or black grade of polyethylene, polypropylene or nylon. Avoid unprotected ABS, natural nylon and standard polycarbonate in full sun.
Sunlight breaks polymer chains through photo-oxidation. The first signs are fading, chalking or yellowing; later the surface cracks and the part loses impact strength. Heat, moisture and some chemicals speed it up.
Plastics for outdoor use
| Resin | UV resistance on its own | Common protection | Typical outdoor uses |
|---|---|---|---|
| ASA | Excellent | None needed for most uses | Siding, outdoor housings, exterior auto trim, signs |
| Acrylic (PMMA) | Excellent | None needed | Signs, lenses, light covers, glazing |
| PVDF and fluoropolymers | Outstanding | None needed | Architectural coatings, chemical and outdoor parts |
| Polyethylene (HDPE, LLDPE) | Poor unstabilized | Carbon black or UV stabilizer package | Tanks, playground equipment, furniture, pipe |
| Polypropylene | Poor unstabilized | UV stabilizers (HALS), carbon black | Outdoor furniture, automotive exterior, crates |
| Rigid PVC | Good when formulated | TiO2 and stabilizers | Window profiles, siding, fencing |
| Polycarbonate | Fair; yellows | UV-stabilized grade or protective cap layer | Glazing, covers, lighting |
| Nylon | Poor natural | Black or UV-stabilized grades | Cable ties, clips, outdoor fasteners |
| ABS | Poor | Paint, ASA or acrylic cap layer | Use ASA instead where possible |
| Acetal | Poor | Black or UV-stabilized grades | Outdoor mechanical parts |
General guidance. Outdoor life depends on the grade, color, thickness, climate and stabilizer package; confirm with weathering data for the specific grade.
How outdoor grades are protected
- Carbon black: blocks UV very effectively in polyolefins and nylon when well dispersed at the right loading.
- UV absorbers: absorb ultraviolet light before it reaches the polymer.
- HALS (hindered amine light stabilizers): interrupt the breakdown reaction; the workhorse for polyolefins.
- Cap layers and coatings: a thin layer of ASA, acrylic or a UV coating protects a less resistant base resin.
- Lightfast pigments: some colorants fade quickly; outdoor colors need pigments rated for weathering.
How to choose
- Define the exposure: full sun or shade, climate, and expected life.
- Decide what matters: color retention, gloss, impact or just structure.
- Pick an inherently resistant resin, or a stabilized grade of the resin you need.
- Check the color: black is easiest; bright colors and whites need lightfast pigments.
- Ask for weathering data (ASTM G154 or G155) on the specific grade.
See also UV fading and yellowing, ABS vs. ASA and PC vs. acrylic.
Grades we source
We source ASA, acrylic, PVDF, and UV-stabilized and black grades of polyethylene, polypropylene and nylon, with a COA on every lot, tested to ASTM or ISO methods. Custom compounding with UV packages and lightfast colors is available. See ASA and SAN, acrylic and color and compounds.
Common questions
What is the most UV-resistant plastic?
Fluoropolymers such as PVDF, along with acrylic (PMMA) and ASA, have excellent inherent UV resistance. Polyethylene and polypropylene become very UV resistant when stabilized, especially in black.
Is ABS good for outdoor use?
Not on its own. ABS yellows, fades and turns brittle in sunlight. Painted ABS, ABS capped with ASA or acrylic, or ASA itself are the usual outdoor choices.
Does black plastic last longer outdoors?
Usually, yes. Well-dispersed carbon black is one of the most effective UV protectors for polyethylene, polypropylene and nylon, as long as the type and loading are right.
Is polycarbonate UV resistant?
Standard PC yellows and loses toughness outdoors. UV-stabilized grades, and sheet with a UV-protective cap layer or coating, are used for outdoor glazing and covers.
How is UV resistance tested?
With accelerated weathering, such as fluorescent UV (ASTM G154) or xenon arc (ASTM G155), and with real outdoor exposure. Accelerated hours do not convert directly to years, so compare grades under the same test.
What do UV stabilizers do?
UV absorbers soak up ultraviolet light before it damages the polymer, and hindered amine light stabilizers (HALS) stop the chain reaction that breaks it down. Many outdoor grades use both.
Tell us the part and where it goes
A polymer chemist reviews every request, then matches your grade or finds a qualified equivalent and prices it.
What to send for an accurate quote
- The grade name, from any supplier, or a data sheet
- Color (natural, black or a custom match)
- Fill type and percentage, if any
- Melt flow, if you know it
- Quantity for this order and what you use in a year
- Ship-to city and state or province