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Re: [GreenYes] /All PET "Can"
In light of Wayne's question (below), I should have added a salient comment
to the information I posted from the Schotland press release concerning the
all PET beverage can.

Monomer PET does have excellent barrier properties, which is why it was
engineered 20 years ago to also have the molding economics it needed to
prevail in the marketplace.

However, physics dictates that as a container's size decreases, the need for
barrier performance increases. This is because the ratio of the exterior
surface increases as a function of the interior volume with decreasing size.

PET works just fine keeping carbonation in 2-liter bottles, and indeed, down
to 16 ounce bottles. However, it does not provide adequate shelf life to
keep pop from going flat in 12 oz. containers.

We've all heard about the need to enhance PET's barrier performance in all
size plastic bottles for beer due to beer's intense sensitivity to oxygen
infiltration.  That led to a number of different barrier enhanced designs
such as that used by Miller beer beginning in 1998.

Well, whether we're talking about a PET bottle or can in the 12 oz. size, my
understanding is that either would require enhanced barrier performance for
carbonation retention above that which PET by itself can provide.

All that the press release obliquely notes in this regard is that "The
PETCAN(R) has multi-layer capability."  Without knowing more factually, I
infer from this, and I have no other facts to go on, that they are
indicating that one of the barrier materials, such as the nylon MXD-6 that
was used in the Miller PET beer bottle, would be layered between the outer
and inner layer of the plastic can.

If this is so, then the question arises of what such a multi-layer barrier
PET can would mean for recyclers.  In a report which the Plastic Redesign
Project I direct issued on the barrier bottles, we found that using the
vendors' own data, and testing protocols that are appropriate for the
industry, at the saturation levels that we would expect to see when barrier
bottles are rolled out in the marketplace, the quality of recycled PET would
deteriorate to the point that the new, promising and high paying
bottle-to-bottle markets would be closed to us due to the yellowing MXD-6

I hope this answers Wayne's questions.

For anyone who wants to read more details about barrier issues, you can go
on-line to:

Peter Anderson
4513 Vernon Blvd. Suite 15
Madison, WI 53705
Ph:    (608) 231-1100
Fax:   (608) 233-0011
Cell    (608) 438-9062
email: anderson@no.address

----- Original Message -----
From: "Wayne Turner" <WAYNET@no.address>
To: <greenyes@no.address>; <anderson@no.address>
Sent: Friday, January 03, 2003 1:37 PM
Subject: Re: [GreenYes] /All PET "Can"

Peter Anderson posted:

"According to a press release from Schotland, a Canadian firm, Water
Investment Network, has developed an all PET beverage can, "PETCAN(R)",
including a PET lid with a built in "easy-open" reclosable devise.  "Because
the lid of the PETCAN(R) is made from the same PET material as the body, the
package is claimed to be fully recyclable and evnrionmentally friendly," the
press release asserts."

And from where will the demand for all these 'fully recyclable and
environmentally friendly' PET cans come?  In 2001 the US exported nearly
half as much PET as it used domestically.  According to NAPCOR, existing
domestic RPET plants are at 81.7% of capacity converting 670 tons of PET
bottles to RPET.  670 tons is equivalent to only 17.75% of total PET bottles
on shelves in the US in 2001.  Additional PET bottles/cans can only result
in lower recycling rates until virgin PET users begin to demand RPET as the
preferred feedstock.  With the price of crude oil rising, maybe natural gas
prices will rise to the point that the RPET flake will become an
economically attractive alternative as a feedstock.  But, then, from where
will the conversion capacity come?

Does anyone know the price differential between the amount of natural gas
(ethene/ethylene?) to produce one ton of PET versus the price of one ton of

B. Wayne Turner
City of Winston-Salem
Utilities Division
phone: (336) 727 8418
email: waynet@no.address

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