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[GreenYes] mixed plastic products
in response to Gretchen's comment below, the Chelsea Center has 
sponsored some research on development of an aggregate made from 
mixed plastics and fly ash.  Go to the Center website,, and click on publications to find the reports. 
They are under technical reports.  The aggregate has been tested in 
concrete block and is found to lighten the concrete as well as reduce 
its cracking.  The process can used mixed plastics WITHOUT PVC-- I 
believe the melting point of the mixed plastics releases toxins from 
the PVC.  Also I would personally be a bit concerned about using 
plastics from electronics that contain brominated flame retardents. 
But I believe in this case the researchers only dealt with mixed 
plastics from MRFS.

>Another option we should seriously revisit is mixed plastic lumber (and
>other multi-dimensional products now possible).
>   Yes, there are wonderful products available from LDPE & wood that are
>terrific for uses like decks.  But I'm talking about really mixed
>plastics--blow-mold & injection HDPE, LDPE, PP, plus measured amounts of PVC,
>PS, PET, & other.  Not to mention tramp materials (paper & plastic labels,
>bits of dirt, grit, glass, food, whatever).
>   As long as you have 60% polyolefins (HDPE, LDPE, & PP) and half & half film
>and rigid--both of which closely match the percentage of these resins in the
>discard stream--then existing, proven technologies can produce landscape
>timbers, posts, fences, compression molded (all-of-a-piece) pallets,
>interlocking blocks for retaining walls, more.  Not to mention lumber for
>park benches, picnic tables, and other things we should not be making from
>   Mixed plastic recycling gives a solution for what to do with dirty plastics
>from single stream collections; sidesteps the issue of food contact; provides
>an end-use for #3-7 resins PLUS margarine, yogurt, & most other wide-mouth
>HDPE containers; gives products that encapsulate (hence reduce) a percentage
>of MRF outthrows, more.
>   Folks have asked "how many picnic tables & park benches can we use?"  I
>look at parks, beaches, bus stops, other potential gathering places, & think
>lots more than we have now.  The technology is relatively cheap compared to
>other plastics recycling systems. And it's possible to do recipes that allow
>a range of colors besides brown, green or black.
>   It's worth some thought...
>Gretchen Brewer
>Earth Circle
>San Diego, CA
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