How to recycle PET Plastic??
This topic contains 7 replies, has 6 voices, and was last updated by Anonymous 1 year ago.
Recycling of thermoplastic products has been common in past years. The thermoplastics such as PET resins are relatively easy to recycle as their polymer chain break down easily at low temperatures. PET plastics are being recycled on a very large scale globally. Recycled polyethylene terephthalate is termed as RPET (Recycled polyethylene terephthalate). According to PETRA, the PET Resin Association, the U.S recycling rate of PET is about 30%, and it is almost 52% in the European Union. Almost 1.8 billion of total PET was recycled globally in 2015 which was used to make a variety of end products.
Recycling Process of PET may be different for different plants but general steps followed in this process are as follows:
Bottles are segregated individually and unwanted materials are removed manually or by an automated system.
To prevent any kind of contamination bottles are cleaned inside and out thoroughly to remove all kind of dirt.
After cleaning bottles are sorted using infrared radiation technique, to determine the type of polymers present in bottles. Bottles are also sorted by their color (blue, natural green or mixed).
Further bottles are shredded into flakes which have to be washed again. Even this step can be missed and bottles can be directly melted to produce different shapes.
At last shredded PET, plastics are melted to further produce plastic pellets.
RPET produced after recycling of PET resin is used to produce a number of end segment products such as automotive parts, PET containers, sheet and films, industrial strapping, luggage, polyester carpet fibers and in clothing (T-shirts, sports clothing, athletic shoes etc).
Has someone already succeeded with making a final product with recycled PET? As i read, temperatures must be in a very small range.
I am especially interested in this (from the link):
PET material is extensively used as sheet stocks for CNC machines. CNC machine is used to manufacture multiple numbers of products where PET material is used as a basic material in the production process.”
PET like PA6 or PA10, or PBT, are more difficult to process because of their melting temperature is quite high for plastic. So whenever you are going to melt it, it will degrade itself quite fast (fumes + weaker material) and be very liquid.
We succeed to process 1-5mm flakes through the oven in a tile mold for the Trashpresso project. (https://trashpresso.com/trash-tech/) 290°C for 40min with a sieves that allow putting an extra quantity of flakes into the mold.
To process PET in very high quality, you need to enhance the crystallization before. It will make it stronger to high temperatures. But that process is not covered yet by Precious Plastic.
I second that question: has anyone been successful in using PP machines to make a product from PET? Any experiments happening out there? What have your results been so far?
m-etmmerecyclage, hey ! thanks for sharing – wasn’t aware there is a next gen PP in this universe yet – keep shooting – great stuff – i hope you guys release the sources one day …
experiments: yes, I tried melting 5mm flakes in an oven – with exorbitant high energy consumption – but no success at all and it just confirmed what I knew from 3dseed: the PET flakes have to be grinded down to 1mm particles to ease further processing. However, there will be a grinder coming in October and it’s nothing more than 3 knifes mounted on a hexbar and a stationary knife ( i can post pictures if you like). You can install this in the v3 shredder but you need 700 – 1200 RPM to make this work well. Other than that, I know you could use the injection but no idea how good this is for the machine over long. Possibly it’s best to make a heated mold with cartridge heaters just.
products: yes, but it’s 3d print then and as far I understood, it needs additives but not sure though.
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