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Weathering

When ABS is used for extended periods of time in outdoor locations or under fluorescent lights, discoloration or distinctive degradation of properties will occur. This phenomenon is known as "weathering" and this page will describe the corresponding mechanisms.

The cause of weathering-related ABS problems is light-induced degradation of polybutadiene, and as a result of this, the effect of rubber in generating impact strength is eliminated. Furthermore, this type of degradation is characterized by its restriction to surface layers.



Change in Color


ABS
red coloration
ABS
blue coloration
  Before exposure After
100 hours
After
200 hours
After
500 hours
  • Severe cases of discoloration due to weathering (accelerated aging test,sunshine weathering, no rain)

It is necessary to take degradation of the coloring agent as a result of weathering into consideration, and it is important to carefully examine the coloring agent being used. In the case of reds, blues, yellows, greens, and other vivid colors, it is important to choose a coloring agent with good weatherability properties in advance. Furthermore, changes in the discoloration behavior of the added coloring agent are monitored in terms of color changes in the molded component.

 When coloring is being ordered, it is important to indicate that "Weatherability is a requirement."

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Change in Luster


Degradation of plastic surface due to photo-oxidation(accelerated aging test, sunshine weathering, examination using a scanning electron microscope)

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Before exposure
   
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After 500 hours of exposure with no rain

Little reduction in luster, but micro-level cracking has occurred.
   
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After 1,000 hours of exposure with rain 1000hrs.

Breakdown of plastic components has occurred and the surface has a sand blasted appearance, resulting in the loss of all luster. (This is also known as color chalking.)

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Changes in Properties


Changes in characteristics due to photo-oxidation as image.
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The depth of the degraded layer brought about by weathering is in the order of several hundred microns in depth. The reaction to photo-oxidation results in the generation of a thin yellow layer at the surface, and this layer prevents the diffusion and permeation of oxygen, and in addition, it also blocks out light. Accordingly, any further photo-oxidation at the interior of the component is prevented. If it is also desired to prevent the generation of this degraded surface layer, we recommend the use of our weatherable grades.

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 UMG ABS Ltd. accepts no responsibility for the quality or safety of any customer products which use our materials or which have made use of any type of data provided by this company.
 Customers are requested to independently determine the suitability of our materials for their products. We also request that sufficient attention also be paid to laws, regulations, and industrial rights.


molded part cracking
molding defects
weathering
painting defects