Usually, there is no way to recycle the bottle cap according to the plastic material.
For the bottle caps of most beverage products, polyethylene (PE) and polypropylene (PP) are commonly used in the market.
In the actual processing process, the content of HDPE and PP in the recycled materials is uncertain, and the density of the two is not much different. Although there are many sorting methods, they are still often mixed with each other during recycling processing, and the performance of the recycled plastic products is much lower than before.
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There are various kinds of pollution
Taking HDPE capacity I unpacking as an example, various pollutants will occur in the whole production stage of HDPE regeneration:
1) For example, PP sealing and PP pump head will appear in the manufacturing process of HDPE products, which will be affected by product design factors.
2) Or in the collection process, recyclers mix HDPE and PP containers with similar materials and shape types that are difficult to distinguish;
3) Pollution caused by environmental factors and pollution caused by reprocessing.
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What is the key impact
Horizon Jun: communicate with recycling bottle cap re granulation enterprises and summarize the following PP pollution problems encountered in HDPE recycling process
The employees of a recycling enterprise calmly said that the impact of PP bottle caps containing 2-3% in waste products on the reuse of HDPE can be ignored.
In terms of compatibility, due to the poor compatibility between PP and HDPE injection parts, if the content of PP exceeds 5%, it will lead to phase separation in the crystallization process, and a small amount of PP added to HDPE will also reduce the low-temperature impact strength.
When the PP content exceeds a certain amount, the toughness of HDPE injection molded part recycled material itself is poor, and the toughness will decrease rapidly after mixing.
In addition, compared with 100% HDPE of similar models, the content of PP in HDPE has an impact on the processing performance, especially on the heat radiation resistance.