Solutions for Yellowing of Polycarbonate

2025-06-19

Why choose UV resistant polycarbonate material?

-Ideal for guarding performance and transparency in demanding environments

Polycarbonate is an ideal material for many medical applications due to its excellent transparency, strength and dimensional stability

Although polycarbonate has excellent performance, after ultraviolet irradiation, the color of the product will change, and the transmittance and physical properties will also be significantly reduced. (As shown in the image on the right, polycarbonate sheets that have been exposed to prolonged sunlight outdoors exhibit noticeable yellowing and a loss of transparency.)

To the untrained eye, discoloration of polycarbonate may appear to be merely a slight reduction in transparency and clarity; however, in applications such as building materials and medical devices, the resulting decline in performance cannot be ignored. Prolonged exposure to ultraviolet (UV) radiation can cause irreversible changes in the stress, tensile strength, and impact resistance of polycarbonate products.
Therefore, if your product requires polycarbonate that can withstand prolonged exposure to sunlight or needs to be disinfected using UV light, we recommend using UV-resistant polycarbonate.
polycarbonate yellowing
If you need UV-resistant polycarbonate, please contact us. ➡️+86 15837933829

1. Polycarbonate yellowing

1.1 Why does polycarbonate yellow?

Chemical formula of polycarbonate
The fundamental reason why polycarbonate (PC) is transparent is that it is an amorphous plastic.
The molecular structure of PC material is shown in the figure on the left. The bisphenol A unit in the backbone contains two ortho-linked benzene rings, resulting in an asymmetric structure, while the connected carbonate groups (-O-CO-O) are flexible and lack regularity.
This structural composition of polycarbonate prevents the molecular chains from aligning and crystallizing during cooling and molding, resulting in an "amorphous state." It is precisely this structure that causes polycarbonate to scatter almost no visible light, thereby giving the material its high transparency.
It is precisely this amorphous state that causes a lack of internal stability in the material. When polycarbonate is exposed to heat, oxygen, or ultraviolet light, or when trace amounts of metal catalysts remain within the material, the carbonate bonds break and the material oxidizes to form quinone compounds.
Quinone compounds absorb the blue light in visible light and reflect yellow light, leading people to believe that the polycarbonate has yellowed. 

1.2 The Hazards of Yellowing in Polycarbonate

  • Deterioration in appearance

The most obvious sign of yellowing in polycarbonate is a decrease in transparency and a significant increase in haze, which is critical for applications in the automotive, medical, home appliance, and optical component industries that require high aesthetic standards.

  • Deterioration in mechanical properties

Yellowing of polycarbonate is typically accompanied by a deterioration in the material’s properties, primarily manifested as reduced impact resistance, decreased elongation, and increased susceptibility to cracking (particularly stress cracking).

2. How can prevent polycarbonate from yellowing?

The yellowing of polycarbonate materials is primarily caused by prolonged exposure to ultraviolet light, oxidative aging, and use in high-temperature environments; therefore, the following situations should be avoided during processing and use:
  • Avoid prolonged processing and overheating, to prevent molecular degradation caused by excessive heat and shear, during processing, if temperatures are too high or shear forces are too great, the PC molecular chains may be severed or thermally degraded, accelerating the yellowing process of polycarbonate. Therefore,strictly follow the material's processing guidelines. 
  • Avoid cleaning polycarbonate products with acidic, alkaline, or alcohol-based cleaning agents. Polycarbonate has poor resistance to most chemicals, particularly alkaline and ketone-containing chemicals. Contact with these chemicals accelerates the aging process of polycarbonate; therefore, avoid contact with the aforementioned chemicals during use.
  • Avoid using polycarbonate materials in environments exposed to direct sunlight outdoors. If outdoor use is absolutely necessary and high transparency is required, consider using UV-resistant polycarbonate materials or MABS material (methyl methacrylate-butadiene -acrylonitrile-styrene; this polymer offers excellent transparency and good UV resistance, and finished products retain good mechanical and aesthetic properties even after long-term outdoor use).

3. UV resistance polycarbonate material supplier

Brand Character Advantages
Covestro A leading manufacturer of polycarbonate, formerly part of Bayer of Germany Covestro Makrolon, a brand with a significant global market share. Long-term inventory of Makrolon 2407, a low-melt-index polycarbonate with UV stabilizers and mold release agents.
Sabic A chemical industry giant with production lines for a wide range of chemical products Sabic has extensive experience in producing polycarbonates for a wide range of applications, from UV-resistant grades such as Sabic 123R and Sabic 143R to food-grade, medical-grade, radiation-resistant, and high-temperature-resistant grades.
CHIMEI A Taiwanese polymer manufacturer specializing in the supply of basic-grade polycarbonate With a significant cost advantage, the company holds a large market share in Southeast Asia and East Asia. Its main products, CHIMEI WONDERLITE PC-110U and MVR 10, offer excellent UV resistance.
Teijin Japanese manufacturer of high-performance polymers We have a significant competitive edge in specialty engineering-grade polycarbonate plastics, with particular expertise in the production of optical-grade and medical-grade polycarbonate.
Lotte One of South Korea's three leading polymer manufacturers Leveraging mature refining and petrochemical processes, the company has secured a significant market share in Southeast Asia thanks to its low production costs. Its primary UV-resistant polycarbonate products include Lotte PC-1100U and MVR 10, which offer stable and superior processing conditions.
LG chemical South Korea's leading manufacturer of polycarbonate The company’s Lupoy series of polycarbonates offers excellent optical and processing properties; its primary UV-resistant polycarbonate product is PC 1302-10.
Wanhua chemical China's Leading Brand of Polycarbonate With its significant cost advantage, the company has captured a large share of the Chinese market; its primary UV-resistant polycarbonate material is Clarnate A1227.
If you need UV-resistant polycarbonate, please contact us. ➡️+86 15837933829

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