What are the reasons for the fading of plastic masterbatch and how to prevent it?

As an environmentally friendly, economical, and practical polymer composite coloring material, color masterbatch has been relatively mature and common in the field of plastic coloring. The color masterbatch industry has shown a good momentum of development in the global and domestic markets. Plastic masterbatches provide end users with diversified choices and play an important role in enhancing the value of plastic products. However, in some cases, these color masterbatches for plastics are easy to fade, especially under the pressure of harsh conditions. Below we will introduce the reasons for the fading of the plastic masterbatch and how to prevent it.

 

 

Reasons for the fading of plastic masterbatch

1. Light causes plastic color masterbatch to change color

Light stability is an important characteristic of plastic products, especially products used as outdoor furniture. Masterbatch manufacturers have been doing their best to continuously improve this feature with the goal of adding more value to the final product. For outdoor plastic products, exposed to strong light for a long time, the level of light resistance and sun protection is an irreplaceable indicator, which needs to be taken seriously when inspecting plastic masterbatches.

 

2. Acid and alkali resistance affect plastic masterbatch

The fading of the plastic masterbatch is also related to the chemical properties of the colorant, and the chemical resistance plays an important role in determining the length of time the plastic product can maintain the color. Chemical resistance includes acid resistance, alkali resistance and oxidation-reduction resistance. For example, cadmium yellow is not resistant to acid, while molybdate red is resistant to dilute acid (low concentration acid solution). However, this red pigment is very sensitive to alkaline solutions.

 

 

How to prevent the color masterbatch from fading

1. Light fastness is divided into 8 grades, VIII grade means the best performance. For products that require weather resistance, experts suggest that the level should not be lower than level VI, while for other products (such as indoor objects), the level should be maintained at level IV or V. Generally speaking, the light resistance not only comes from the plastic color paste but also is affected by the carrier resin. This can be explained by the changes in the molecular structure of the resin caused by ultraviolet radiation, leading to fading. Adding light stabilizers (such as ultraviolet light absorbers) to the masterbatch can improve light resistance and color retention.

 

 

2. Thermal stability/heat resistance is generally regarded as the highest temperature at which the molecular structure of the masterbatch does not change, so there will be no fading or discoloration during the manufacturing process. Different types of plastic masterbatches have tested different degrees of heat resistance. For inorganic colorants composed of metal oxides and salts, it has better thermal stability than organic pigments, and the building molecules of organic pigments are easily decomposed into small fragments at a certain temperature. Generally, heat resistance lasts about 4 to 10 minutes. If the processing temperature is higher than 280°C, careful consideration and selection should be made to find the most suitable color masterbatch for plastics with excellent heat resistance.

 

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