Brentwood Plastics blog

Plastic Films Substitution

Posted by Joel Longstreth on Fri, Oct 04, 2019 @ 06:13 PM

Everybody wants replacements for politically incorrect plastic films to be exactly like the original.  No property trade-offs.  No exaggeration. 


Would these same people expect the same results from direct substitution of stevia, xylitol or saccharin ?

There are many drivers.  Back in the 1990's when PVC started to fall out of favor, we got calls for PVC replacement.   The major complaint about our metallocene which mimicked the "hand" of vinyl was that it did not seal in the heirloom RF sealers.  The expectation was that a non-polar molecule would behave just like a polar molecule.  Reluctantly, new sealing techniques were developed as a work around. 


Skip ahead to this past summer.  We got literally dozens of calls for our equivalent to PVC cling wrap for packaging corn because WalMart does not want PVC in their stores.  Even if they found a polyethylene that was clear enough and ran in the usual machine, the shelf life would not be the same due to difference in permeability. 


PEVA ( polyethylene with ethylene vinyl acetate ) has emerged as the film of choice for shower curtains because it is not PVC and is sealable by RF with minor modifications.  

We wasted a lot of resources developing a substitute for PVC in commercial wallcoverings.  The greenbuild culture despises PVC but they are stuck with it.  Only PVC passes E 84 because it is naturally self-extinguishing.

The interest in percieved sustainable films has hit a tipping point as products are being designed for more of a "circular" than "linear" economy.   Designers are finding there are many frustrating hurdles to overcome.



Just when you think you've seen it all department - today somebody inquired about a substitute for a coextrusion of LDPE / Nylon / LDPE.  They wanted a certifiably compostable film just as tough as the coex structure with the sealability to nonwoven.  At first I thought it was a prank.

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Topics: PVC free plastic, PVC free, PEVA film, PEVA, Non - PVC, PVC substitute, sustainable packaging,, green plastic

PVC replacement is complex

Posted by Joel Longstreth on Fri, Sep 27, 2013 @ 05:12 PM

 PVC replacement is not as simple as finding a polymer which passes the "duck" test at a lower price.  PVC substitutes require workarounds because PVC has unique characteristics.

PVC is not inert.  It reacts with solvents found in inks and adhesives more than simpler inert commodity polymers.  Inks and adhesives which have evolved to be compatible with vinyl will not have the same results when a different plastic film is dropped in.  If we've heard it once, we've heard it literally dozens of times - " your PVC substitute is no good; it doesn't act exactly like our heirloom vinyl."  Nobody wants to have to bring in different inks, different adhesives, change the line speeds, drying conditions and embosser settings because they love mother gaya.  

If there's a volume buyer who is willing to pay a green premium, we have yet to meet them.
Billboard printers process truckloads of PVC film daily.  Nobody ever asks where the used billboards end up ( answer: in the landfill where they degrade into chemicals we don't like to talk about ).

RF welding is the same script.  PVC is what is known as a "polar" molecule.  It responds to radio frequency waves, hence the name RF for short.  The radio waves induce the molecules to start spinning.  This creates friction and welds from the inside out - the complete opposite of heat sealing which is done by heating from the outside.  Other polymers such as urethane react similarly, but not anywhere near as much as PVC.  Non - polar plastic films are anathema to established RF welding shops who are not about to make capital investments until their hand is forced.  

The scrpt is always the same.  The play has three acts with a run time of about 120 days.

Purchasing searches for a PVC replacement because a major customer who has been forced to eliminate PVC might be lost.  Specs for PVC are proferred to potential vendors along with promise to make minor tweaks to manufacturing process if necessary and to pay a green premium.


Suppliers submit candidates for evaluation.  Performance properties mimic PVC as closely as possible.Minor tweaks turn out to be major capex requirements, line personnel are hostile and reluctant to make adjustments. After the third iteration, all parties are frustrated.  New suppliers are dismissed as incompetent. 


Once enthusiastic new suppliers are thanked either for succeeding in cracking the code or for their time and efforts if they have failed.  In over 90 % of cases, they are told the information will be held in abeyance if there is a real impetus to find a PVC substitute.

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Topics: PVC, PVC free, phthalates

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