Mixing virgin and recycled Polypropylene Granules in single use plastic straw extrusion machine

[Azeen]

Hi All,

If you have experience, what are your thoughts on mixing recycled and virgin granules for producing single use plastic drinkinf straw? Or just using 100% recycled.

We bought an extrusion machine and the manufacturer said the machine needs vigrin granules, but any reasons why we cannot use recycled?

This is a screenshot of their recommended PP:

 

[IRstuff]

Not sure about PE specifically, but recyclability of plastics in general is a myth; the "recycled" plastics are typically of lower quality and do not perform as well as plastics made from virgin material, be it through contamination or thermal cycling effects

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert!

https://www.youtube.com/watch?v=BKorP55Aqvg

faq731-376 forum1529 Entire Forum list

http://www.eng-tips.com/forumlist.cfm

 

[btrueblood]

See if you can get a mixed batch from a reliable supplier, with certification (by testing) that it meets all those requirements on the list.

FWIW, I agree with IRstuff, and believe it would be unlikely for the above to happen. Thermal degradation by oxidation and chain scission for polypropylene is a known issue. According to wikipedia, less than 1% of PP is recycled in the US; other articles suggest the reason is low demand.

But, recycling is not "generally a myth" - contrast PP with PET bottle recycling, which can be higher than 80% in some countries (i.e. more than 80% of bottles consumed first time are reprocessed, though not necessarily into new bottles); PET has lower thermal/UV degradation rates and can also be chemically reprocessed to virgin material.

 

[IRstuff]

The myth is that plastics can be recycled ad infinitum, ala bottle back to bottle; which it can't. In reprocessing back to virgin, consumables are not necessarily saved, since processing can incur significant water usage, among other things.

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert!

https://www.youtube.com/watch?v=BKorP55Aqvg

faq731-376 forum1529 Entire Forum list

http://www.eng-tips.com/forumlist.cfm

 

[3DDave]

For my taste Re-Cycle means back to the same product. Aluminum and steel remain #1. Re-Purposed describes the most that plastics seem to get. Contaminated with: Adhesive paper labels, food residue and oils, dirt, oxidation, co-extruded with other polymers, pigments, dyes, plasticizers, UV protectants, and I'm sure dozens of other materials that plastics companies add to make the first round through the process the best that aren't separable or helpful to users of other processes.

Why only virgin granules? So the user of the machine is far less likely to call up and complain that the machine doesn't work right after getting fed some random mix that the re-cycler claims is just fine.

 

[Linda0510]

Recycled material it's quality of course is worse than virgin material.

http://www.toponew.com