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We blog only about timely and relevant topics.  The software does not allow rearranging posts, so they are chronological.  You can browse by topic or keywords by scrolling down on the right side.

Brentwood Plastics blog

Joel Longstreth

Recent Posts

Buy American / Hire American ? - as if !

Posted by Joel Longstreth on Wed, Apr 06, 2016 @ 05:44 PM

When George W. Bush asked the premier of China what kept the premier up at night, the response was "finding jobs for 25 million people a year."  Products in the mature life-cycle stage are imported everyday to the US at artificially low prices.  Why does the U S government let this happen ?  Why is there no anti-dumping outrage ?

 

In retrospect, Smoot-Hawley was a causative factor of the depression.  Today's supply chain is interdependent and complex, so tariffs aren't the solution for complicated products.  

Simpler items are imported in large volume to the US at bargain-basement prices.  We're seeing a common thread.  The cost of the finished product mostly from China, is at the price of raw material here in the US, even in a capital-intensive industry such as plastics. Before getting into specific examples, let's look at why. 

( Personally, my cynical opinion is the U S government likes cheap goods to show lower inflation rates and lower COLA  )

My guess is it's a combination of factors.  The two biggest advantages for manufacturers in certain countries are currency manipulation and raw material subsidies.  American manufacturers have the disadvantages of higher wages and the not so hidden costs of regulations and taxes.  Ocean freight is cheap.  Inland freight is equal.

Taxes are a factor of production.  Much has been written about the additional burden of regulation and how it puts U S manufacturers at a disadvantage.  

" One of the single biggest areas we should see some immediate relief 
is from some of the regulations that have stifled our industry
and curtailed some of the growth. "

- William Carteaux, CEO of the Plastics Industry Association

Here is a summary:

  Factor of Production   Advantage   Comments
  direct labor   China  plentiful labor compliment but hard to train  
  freight    none  ocean freight is cheap
  regulations   China

fewer restrictions on solvent inks or disposal.  No OSHA.  No EPA, etc.

  taxes   China  
  resin cost   China US is low cost producer, but China gets big subsidies
  currency manipulation   China  
  electricity     ???  
   logistics   U S   China 
  X files factor   U S    

We have swerved into a few cases in our microcosm which just might be indicative of what's going on on a macro-scale.  Here are a few anecdotes:

                                                              Drawstring stock ice bags              

                                                                    drawstring ice bagstock ice bags
One of our customers does not understand why the cost of drawstring ice bags made in China is literally 1/4 the cost of US made.  The resale price of the finished bag is practically the cost of U S - manufactured. That's the resin pellets before being extruded into unprinted rollstock.   With UPS charges, the convenience store pays $0.04 each. American-made bags would cost about $ 0.09.  Let's face it - who wants to pay 6 cents more for a bag of ice ?  The convenience store operator would rather give up two pints of blood. 

                                                    Red and Yellow barricade tapes

  

We make heavy metal free red and yellow rollstock, sell it to customers who print, slit and box, often untouched by human hands.  Our customers cannot compete with Chinese goods which contain 1% lead ( contact us if you want to see the test results )  printed slit and boxed at the same price as rollstock.  The imports are not constrained by HMF heavy metal free resins or water-based inks.  American consumers don't care about continual dermal exposure to lead, so everybody's happy.

shower curtains

 

We have recieved several inquiries from manufacturers of shower curtains in China.  They see the handwriting on the wall.  Chinese labor and electricity are going to approach the costs here at some point.  They are also looking into complying with WalMart's P R ploy - U S made ( the reality is WalMart will only pay 5 to 7% more for American made because that's the maximum upcharge consumers will pay ).  They are incredulous about costs of production here vis-a-vis China.  They go into sticker shock about the price of resin and don't believe us when we go so far as to tell them what EVA resin costs. Everything - resin, ink, labor, electicity, payroll taxes, OSHA, etc. is more here.  Until the factors of production lines cross, they will continue operations in China.

There's no telling how many millions of pounds of plastic these 3 examples add up to, let alone how many U S jobs ( " American carnage" according to Donald Trump ) are at stake.

So there you have it.  Reality is the consumer is conditioned to paying lower prices.

The good news is there is a whole lot of "re-shoring" going on.  It started long before Donald Trump threatened to slap an import tax on companies who move operations outside the U S.  The low prices from China come at a price.  I have talked to many people who are animated when they say they are "through with China ! "  They have paid for the low prices with their sanity.  If they find one of a few suppliers who are not out to rip off the the importer ( with no concern for repeat customers ), the execution is slap-dash and the parts are sloppy.  It's like the X-files.  Nothing is as it seems.

 

Injection molders are pulling molds wholesale and telling customers to take or leave the domestic price.  To be fair, logistics from the producer to the port have improved.  Not so long ago, you didn't know where your container was until it got scanned in to the ship.  

When it gets to the point that Fox Conn gets serious about migrating operations to the US, somebody is getting frustrated.  

There's plenty of good news to go around these days especially in automotive, about domestic investment in manufacturing.   Who could have imagined that Mike Lindell would invent a pillow and employ 1,500 people in Chaska, MN ?  Then there's other news about labor-intensive industries mostly garments, moving operations to Africa for lowest cost " cut & sew".  

 

                                     Africa has been called the last frontier for cheap labor.

Can you blame the management of globocorps ?  It's nothing new and it's basic econ.  Factors of production flow to the most favorable environment.  Management has a fiduciary to maximize shareholder return.  Barry Bluestone wrote about it back in 1982 in the book " The De-Industrialization of America".  It's not enough to be profitable.  The profit center which is the least cost producer is going to stay open and get the CAPEX.  The higher cost plants get shuttered.   The Economist says the multinationals may be over the hill.

Since the 2008 downturn, US manufacturers have automated extensively, but there are limits. Consumers are not williing to pay $ 4,500 for a US -made iphone yet.

Trump's persuading Carrier to stay in Indianapolis is a great story, but could whipsaw into the government dictating labor costs.  The most labor-intensive industries would be most affected.  Only time will tell how unwinding trade agreemens will play out. 

In any case, American businessmen just want a level playing field.  Good luck with that.

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Topics: reshoring, buyamerican

Factors Determining Shelf Life

Posted by Joel Longstreth on Tue, Apr 05, 2016 @ 06:39 PM

Shelf life is subjective.   The definition of "use by" or "sell by" date depends on criteria and varying degrees of emphasis.   These dates are understandably conservative.  

 

Let's look at both the judging criteria and interdependent factors affecting shelf life.

The judging criteria are:

odor and taste      appearance      texture
Obviously the most common sense must-haves for consumer satisfaction, these criteria do not pick up on other factors which have the potential to sicken or kill the customer.

weight loss
Package must not dissipate moisture to comply with weight and measures.

micro loads  
Critical in fresh, unpasteurized food.   Judging by total micro load is an oversimplification and puts the processor in an impossible position.  Something is going to grow on the surface of the product, either friendly aerobic
( in the presence of oxygen ) or anaerobic ( no oxygen present ).   It's a zero sum game microbiologists call competition.  The battle between these types of bacteria dates back to pre-Cambrian times.  Aerobic = good, friendly.  Anaerobic = bad.  Anaerobic is where emerging pathogens such as shigella, campylobacter jejuni and classic clostridium botulinum thrive.  What's scary is listeria mycocytogenes  grows in both conditions and is undetectable to odor and taste.  A bag of salad which has been stored at 38 degrees for 25 days may look good, feel crunchy and taste fine while fraught with stealth populations of listeria.

Think petri dish.  The product is a growth medium for cultures of friendly and dangerous bacteria.  Microbiologists talk about " logs " of micro loads.  This is short for "logarithmic" growth starting with "seed" populations.  Fresh cut fruit has taken longer to catch on due to the higher amount of sugar vis-a-vis vegetables. 

Agricultural and Agri Food Canada ( AAFC ) for short usually picks up on listeria contamination in salad first.  No real surprize there.  The bags have a week to incubate in transport from California with greater chance of temperature abuse.

headspace analysis
Tracking headspace gases interpolates when the package will go anaerobic.  The biggest mistake in headspace analysis is not getting enough data.  Simply checking one or two packages every few days does not provide a true picture.  The right way is to sacrifice a lot of product, check several packages every day then graph the results after throwing out the highs and lows.

processing factors

raw material  
This refers to either the animal or vegetable and how it was handled not just in transport to the processing facility. In the case of vegetables, it's smart to look at conditions before the seed was put in the ground.  If manure was used to fertilize, Escherischia Coli has a way of finding it's way into the processing plant as seed populations.  Avoiding cross contamination requires close attention to HACCP.

processing conditions  
Before personnel set foot on the production floor, it is best practices to educate them about sanitation.  Seed populations of pathogens often enter the plant on the hands of employees.

packaging  
Packaging cannot make an inferior product into an acceptable product.  OTR is key.  For meats, fish and cheese, a barrier is essential.  For fresh produce the proper barrier or lack thereof is the lynchpin.  A lot of emphasis is put on OTR.  An overlooked factor is the CO2 transmission rate - about four times the OTR.  So the highest OTR without spoiling prevents the dnagerous anaerobic CO2 buildup.

distribution chain

 

Temperature during transit is not a factor with pasteurized canned or bottled product.  Wines can be ruined in just a few hours in a hot car.  For fresh products, when measuring headspace it is important to mimic as closely as possible the anticipated temperatures in the " cold chain".  This can be a touchy subject.  Who wants to be the one who has to tell their customer spoilage is due to breaks in the cold chain at  the customer's distribution hub ?  Besides, every Thermo King is at exactly 38 degrees F throughout the entire truck, right  ?   Sending the customer the impartial results from a Ryan often backfires.

I have seen several attempts to quantify the definition of shelf life by assigning a point value to each category adding up to a total of 100.  It never works.  If an item fails in any one of the criteria, it fails.

did you know ?

In the early 1800's there were an estimated 15,000 stills in Kentucky.  Distilling whiskey was a very rational alternative to selling corn.  The reason: practically indefinite shelf life.

The most toxic substance on this planet is not man made.  It is produced by Clostridium botulinum to defend itself against other predatory micro organisms.   Botox anyone ?

Meals Ready to Eat, or MRE's are expected to have a shelf life measured in years.  Exactly how long is time and temperature dependant.  If an MRE is puffy, you now know why it's gone bad.  It has gone anaerobic.

It is estimated that 40% of food in undeveloped countries spoils en route to market.  In the US, consumers pitch about 40% of their food.  Neither one is good from a methane generation standpoint. 

 

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Topics: shelf life

High Density HMWDPE Conundrum

Posted by Joel Longstreth on Wed, Mar 30, 2016 @ 12:44 PM

The acronyms HMWHDPE and  UHMWHDPE are confusing.  This discussion breaks down high molecular weight jargon.

alphasoupHD-2.jpg 

Starting with the MW bit -  MW is short for molecular weight.  MWD, or molecular weight distribution is the full name.  Accoring to Handbook of Polyethylene by Andrew Peacock:

     " The size of a polyethylene molecule is normally described in terms of its molecular weight.  All polyethylene resins consist of a mixture of molecules with a range of molecular weights.. The average molecular weight and the distribution of chain lengths comprising a polyethylene resin profoundly affect is ( sic ) properties.  The molecular weights of molecules found in commercial resins may range from a few hundred up to 10 million... Often it is found that those molecules making up the higher molecular weight fractions also display the lowest levels of branching. "

Without getting deep into the five geeky ways to measure MWD, suffice to say that a high molecular weight resin is concentrated, very crystalline ( little short chain brancing ) and very dense. No surprize that by definition the density is high - high density ( HD ), or over .940 gm / cc.

So HMWHDPE = " High Molecular Weight High Density Polyethylene"

As you might expect, these resins are among the strongest polyethylenes pound for pound.  They are so viscous that the ASTM 1238 test for melt index had to be revised when the original Mitsui 7000F came along in the late 1970's.  Melt index is a measure of viscosity.  The test method consists of a cylindrical specimen in basically a heated can with a weight and a hole at the bottom.  The number of grams which come out of the hole in ten minutes is called the melt index.  This provides a crude predictor of the resin's personality.  Garden variety LDPE resins are about 2 grams or the verbal shorthand " 2 melt".   Mitsui 7000 F, American Hoechst GM9255F2 and Conoco / Dupont 5000 had values of + - 0.05.  So the HMW film resins are now tested with a " high load melt index", or "HLMI" which simply means higher weight to get a more meaningful sample.  Some prefer to make it sound more daunting by saying  "HLMIHMWDPE."  The most cotidien examples are single use grocery bags and star- seal trash bags.

 

Did you know ?  If there is not adequate haul-off speed, thicker HMWHD films will be weaker.  Why ?
the strength is a function of how well the polymer is "knitted" in the transverse direction ( TD ).  Here's how it works:  HMHD is made with a "stalk" or "wine glass" vis-avis "in the pocket" in LDPE.

 

 When the elastic energy dissipates, the bubble is created.  The tear strength and is a function of how fast the melt is oriented in the TD.  Simply slowing the line speed will create weaker, "splitty" film.

UHMWHDPE as you might guess is an even higher protein version with molecular weights starting around 2,000,000.  Those are long chains.  That said, most grades are in the .928 to .941 range which fall into the category of medium density polyethylene ( MDPE ). You can't make blown film out of it.  It has to be cast, or made with a slot die.  It is very stiff and slippery to the point of having a weird self-lubricating effect.  This trait makes it a popular choice for conveyor belts. I recently had a partial knee replacement.  Instead of a meniscus, I have a stainless steel end of my tibia moving against an insert of HMWHD in my fibula.  ( i have an image, but it's not for the faint of heart ).  There are lots of uses - the most popular is pressure-sensitive tape commonly referred to as "poor man's teflon." 

For the basics of PE, click here.

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Topics: HDPE, HDPE film resin, HDPE resin, UHMWHDPE, HMWHDPE

What Is Polyethylene?

Posted by Joel Longstreth on Wed, Jan 20, 2016 @ 09:07 AM

What is Polyethylene?

Polyethylene is comprised of long chains of the building block ethylene monomer. Ethylene monomer
C2H4 ( or just "C2" for short ) looks like this in English:

ethylene.jpg

Ethylene monomer occurs naturally in both natural gas and as a component of naptha - the portion of a barrel of oil which cannot be refined into gasoline or oil.  So now you know that correlations between zillions of barrels of oil and plastic grocery bags are just more fake news.

                                      Did you know ?  Climacteric plants produce ethylene to induce ripening.

 

Polyethylene looks like this in English:

polyethylene

How these chains are put together determine the wide variety of resin properties. The fancy name for this is molecular weight distribution, or MWD for short.  MWD influences the 2 main properties which dictate a resins's personaliity - density and melt index.  The variations determine what applications a specific resin will work for.  

Polyethylene is the largest volume thermoplastic resin.  As such, it has a wide variety of uses.  Worldwide, there are probably hundreds of grades just for film alone.

What is Polyethylene?

Polyethylene is very inert.  The prelude to the iconic scene in episode 2 of season 1 of breaking bad illustrates this point.

 

 

The character Jesse called Walter from the store asking about what kind of plastic bin to buy.  Walter told him to look for the " LDPE 4 polyethylene " symbol on the bottom.  Jesse pours hydrofluoric acid packaged in a #2 HDPE #2 on the body in the bathtub.  After the bathtub falls through two floors, Walter explains that hydrofuoric acid is so aggressive that it eats through ceramic and metal ( but not polyethylene ).

 

Melt index (MI) measures viscosity by weighing the amount of plastic resin which extrudes from a cylinder with a hole in the bottom at 300 degrees for 10 minutes. The test method is ASTM D1238. The number of grams is the melt index, or MI.

A low melt index ( under 1 ) is referred to as a fractional melt  or less than a gram / 10 minutes.  Lower MI resins are used for pipe and profile extrusion.   It's common sense that resins with high viscosity (resistance to flow) are inherently strong. In film applications, fractional melt is suitable for shipping sacks and shrink film. Generally there is a trade off between melt index and clarity. The higher the melt index, the clearer the resin.  So a fractional melt is not a good choice when clarity is important and a high clarity "whole melt" or resin with a melt index of over 1.0 is not appropriate for shipping sacks.

By contrast, high melt index resins are used for injection molding.  For injection molding, it is desirable to have a material which flows easily to fill the mold cavity.

This has been a very cursory basic introduction.  To learn about where polyethylene comes from, visit our
post .  Polyethylene is processed by almost every thermoplastic process.

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Topics: polyethylene, LDPE, HDPE

Packaging Film Blame Game

Posted by Joel Longstreth on Tue, Dec 29, 2015 @ 06:59 PM

A plastic film spec properly crafted by a packaging machine manufacturer ensures that the film can always be blamed  That's what an OEM told me last week.

 arguin.jpg

Over the years, we have tried to partner with packaging machine manufacturers with no success.  Now I know why at the tender young age of 63.  We have even cited success stories in which our film has enabled frustrated plant managers to have consistent performance at speeds which exceed the OEM's claims.

 

To use a military analogy, the machine manufacturers are like the tank corps.  The tanks take the terriority and the infantry follows.  The machinery makers just figure the customer will figure the film out on their own.  When a machine is placed, the distributors find it first and swarm in.   Another set of problems arises from lack of continuity of supply when the distributor "shops" every order.

The setting of this worn out script which happened last week was the last stage of an installation.  The upstream issues were sorted out.  The last tech who was packing up and leaving said all three laminated film candidates were bad. Last remaining problem: good end seals, inconsistent back seams and occasional pinholes.  " FIrst time it ever happened" didn't do the customer much good.

dreamstimeextrasmall_2500400.jpg
The panicked customer contacted us.  I explained that if they were getting good end seals, they were hitting the optimum combination of heat / pressure / dwell. (The film is the same throughout, therefore the acid test variable is the sealing jaws.)  The heat and dwell time were both too high, resulting in "overcooking".  Turning the heat down - cooler - solved the problem.  Random pinholes in the end seals were the last problem.  

Turns out the packages were dropped three feet to the conveyor.  The molten film did not have enought time to crystallize.  The impact created the pinholes.  The pinholes disappeared when the conveyor was simply elevated.

We didn't get a sale out of it and consulted for a lot less than minimum wage.   

It's a natural human tendency to blame the party who is farthest away from the scene.  In the packaging business, the Napoleonic logic always blames the film first.  

 

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Topics: packaging machinery, packaging, packaging film

Why Recycled Plastic Content is not Always Practical

Posted by Joel Longstreth on Mon, Nov 30, 2015 @ 03:18 PM

"Recycled Content" must score well in focus groups.  What else could explain why we are getting more requests for recycled content than ever ? 

 The economics of recycling is an entirely separate discussion.  Here are a few reasons why it is not always practical to recycle plastics.

" ( Post-consumer resins are) very important to some brand owners"   
-  Pedro Morales, KW Plastics

 

2ndplantbottle.jpg 

Problem:  With very few exeptions, recycled content compromises the properties of the virgin resin.  This has many ramifications.  Taking the exception first, let's look at polyethylene terephthalate a/k/a PETE #1.  It is not melted down and mixed back in with the virgin resin.  Instead, it is repolymerized.  The polymer is broken down into pure monomer and water and reassembled into pure polymer.  PETE is the only recycled resin approved for medical devices.  Not so fun fact:  the general public chooses to recycle only 1 in 3 PET bottles.

" We need ( post-consumer) polyethylene to be looked at like recycled PET is...  Recycled PET  is sold at a premium ( to virgin PET ).  ( Post-consumer) polyethylene needs that same kind of attention." 
- John  Picciuto, president of Western Plastics Association

For this to happen, post-consumer PE ( #2  & # 4 ) would have to attain the same FDA-approved status that PETE has.  

Really truly recycled plastic is picked up curbside, sorted, reground, repelletized and extruded again.  Internally generated scrap which is recycled internally does not fit the definition, but nobody cares or checks up.

earhaware.jpgearhaware2.jpg

At every step there is a chance for contamination.  Cross contamination with other polymers is one of the top issues for recyclers.  If the recycler is fortunate enough to have a batch of just one polymer, that's not even half the battle.   There are variations on the theme of each resin.  So contamination from the same polymer can compromise the final product.  With each heat history, the performance of the polymer degrades due to dissipation of the anti-oxidant.  Recycling makes the public feel good.  In reality it is downcycling to a less critical application.

Medical and Clean Room Packaging

Would anyone in their right mind want to use a medical device such as a syringe which might contain even trace amounts of toxins ?   We have made film for ostomy bags ( prolonged direct dermal contact ) for over 15 years. It's tough enough just to get prime virgin resin approved.  The resin has been put through four biotoxicity tests. Only somebody who wants to get sued would consider using partially recycled content.  Same goes for surgical drapes which come in brief contact with surgical instruments.

The same hospital that discards a blood presure cuff ( after charging the patient $25 ) for fear of a MRSA lawsuit will recycle / sterilize sharps because it makes economic sense.

disposable blood pressure cuff

Clean room packaging has a very low parts per million threshold for many chemicals.  Introducing the wild card of recycled content would risk recall of an entire shipment and loss of a customer, not to mention getting charged back for having to repackage.

dreamstime_s_17056637.jpgdreamstime_s_22175857.jpgdreamstimesmall_12386776.jpg

 

Food and Water Packaging

PETE is also the only recycled resin approved for prolonged and direct food contact by the FDA.  Same logic applies to food.  Would you feel comfortable with your food being packaged in a container which might contain toxic chemicals picked up as the scrap is transported and processed  ?   Plastics already get enough of a bad rap due to misperceptions and misinformation.


BPA free is an effective greenwash marketing tactic.  Food packaging also gets scrutinized for what is known as leachables and extractables to be sure undesirable flavors are not migrating into food.

cuisinart.jpg images.jpgdreamstime_s_29972885.jpg

 

Deposit Slip and Coin Packaging

deposit_bag.jpgfedcoin.jpg2nddeposit.jpg

All bags in this category must have a tamper-evident immediate bond.  The three things which prevent tape from sticking are moisture, dirt and grease.  As such, they have a zero tolerance for slip, or erucamides which are commonly added to make bags open easily.  Adding in recycled content which may have trace amounts of slip could prevent the tamper evident tape from sticking.  The center image is fifty pounds of loose coins.  It is very difficult to qualify film made from prime first quality resin.  The bags are put through multiple drop tests.  If the seals fail, the film is always blamed, not the bag maker.  You guessed it - recycled resin would make the bags weaker and possibly keep the tape from sticking.  

There are plenty of other applications, but you get the idea.  The common thread - is it prudent to risk so much just to appease a great idea from the marketing department ?  

 

 

 

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Topics: recycling, recycled content, recycled plastics

Prime vs. Off Grade Plastic Resins

Posted by Joel Longstreth on Fri, Oct 16, 2015 @ 04:48 PM

Plastic resins are made by major petrochemical companies.  The choicest cuts are sold by their direct sales force or through their "prime" distributors.  So who sells the near miss or transitional resins which are not exactly ready for prime time ?
 
missedtarget
 

Starting with definitions is difficult because there are no written industry standard definitions of most terms pertaining to resins in this realm.  There is no controlling legal authority which oversees the distribution of off grade resins.  Caveat emptor.

A "major" is short for a major petrochemical company which manufactures plastic resin.  A "broker" is an entity which takes title to the resin which the major deems to be not "prime" resin which falls within the target criteria. The majors sell prime through their direct sales force and prime distributors.

A data sheet lists certain key properties which define the characteristics of a resin. The first - melt index or melt flow - describes viscosity.  This tells the processor the most about how the material will behave and how it will affect the outcome of the part or material.  There are other criteria but going into depth would be too far in the weeds. 

Each of these criteria has a target and acceptable range for what is considered to be "prime".  These are not rigid and fixed.  Rather, they are at the discretion of the product manager at the resin producer.  The parameters change depending on the available supply.  When resin is plentiful, the parameters tighten up.  When resin is "tight", they widen.  It's all a function of what the product managers believe they can get away with.

When a product manager gets a report of fresh lots, she decides which ones are prime and which are considered "off grade" or "near prime".  The prime material gets "certs" and is sold through their direct sales force.  What falls outside the parameters is called "off grade" or euphemistically "near prime", "pencil prime" or "excess prime".  Other lots are called "transitional" which means resin made transitioning from one grade to another. 
 

Off grade, or OG for short, is sold through "brokers ".  By selling to a third party, the origin is obfuscated. Brokers  are supposed to be discreet and sell off grade to customers who are not direct customers of the same majors and preferably into a different application than originally intended ( It gets interesting when brokered resin finds it's way to prime customers ).   A business model which relies on somebody's mistakes at first sounds like a scary business model.  When resin is "tight" or when the majors are trying to raise prices, the brokers don't have much to sell.  The truth is there will always be material available which is rejected by processors. ( We reject several railcars annually produced by ISO 9000 certified major resin companies.  )

The most ethical and truthful brokers graduate to become what is known as "prime" distributors.  They distribute prime to smaller processors not called on by the major's direct sales force.  

It's easy to spot a newbie resin buyer.  They are too smart by half.  They make the rookie mistake of shoving an invoice from a distributor in the face of the direct sales rep.  " I can buy the exact same thing from your off grade broker for 4 cents a pound less !! "  Maybe so for one car.  After that, their reputation precedes them and they get no more deals.  Experienced buyers know the importance of emptying / returning a car quickly so the direct sales rep does not see the car which came from his own plant. 

Fun fact: there are no prerequisites to becoming a resin broker.  

Many brokers misrepresent material while others are ethical and disclose fully the good, bad and ugly about specific lots.  Processors operating on razor thin margins are tempted to save money with resin that's "not exactly" and brokers are tempted to misrepresent to move their inventory. They hope the processor won't know the difference.  Problem: the processor lives with the material and does know when the raw material is not as advertised.  Here is an example:http://www.plasticsnews.com/article/20150924/NEWS/150929945/suit-alleges-processor-was-sold-the-wrong-resin .  
 
The ramifications go beyond the relationship between the processor and the resin producer.  The finished properties of the plastic film or plastic part within a lot or lot-to-lot are affected with variability of raw material.  FDA approval is meaningless.  Just change a few words in a word document and the broker transforms off grade into FDA approved plastic resin.  It's legal and goes on every day.
 
So how can you use this information ?  When doing the due diligence on a supplier, ask them preferably in person if the resin they use is "prime".  Don't be shy.  Ask to see FDA letters and invoices ( for the resin they use to make your product along with "track and trace" records ) with the price of the resin blocked out. If the letterhead is not from a major or authorized prime distributor, it's circumspect.  There is an exception.  Some brokers distribute "generic prime" which has been tested and sometimes blended to fall within specific ranges.
 
Many large brokers have what they call " generic prime " which is analogous to private label brands.  This is usually fair quality and does suffice for utility applications.
 
 
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Topics: plastic resins, LDPE resins, PE resin, PE, prime plastic resin

Surlyn - sometimes there is no substitute

Posted by Joel Longstreth on Wed, Aug 12, 2015 @ 07:54 PM

Surlyn is the most effective, forgiving sealant layer ever invented.  What makes it so effective ?  Why the search for alternatives?  

madscientist

Surlyn's properties derive from what is called an ionomer bond.  An ionomer of sodium or zinc in limbo share with the orbit of polyethylene molecules.  This delivers unsurpassed tack and toughness and strength.  Surlyn seals through contaminants better than any other resin.  This is very important in the large market for subprimal meat packaging.

Surlyn has many other applications besides packaging.  The outer layer of a golf ball is surlyn. 

Surlyn's  is expensive and difficult to process.  Plastic film plant managers were early adaptors of metallocenes because Surlyn is hydroscopic and corrosive to extruder screws and barrels.  Surlyn has to be dried before extruding.  It is incompatible with other common polyethylene resins. 

Metallocenes deliver almost the same hot tack characteristics without the aggravation.  Metallocenes are plug and play.  No drying, no corrosion and lower cost.

 

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Topics: surlyn

Odor and Taste / Leachables and Extractables in Plastics

Posted by Joel Longstreth on Thu, Jun 04, 2015 @ 06:29 PM

 

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Leachables & extractables / odor & taste transfer in packaging have been a perennial source of controversy and product rejections.  Nature's penchant for equilibrium results in migration of substances from plastic packaging into the product.

If glass was a new invention, it would be difficult to get FDA approval due to the elements which leach from it.  It's cliche but true - anything in quantity is poison.

The ramifications of leaching and taste transfer can range from annoying and inocuous to toxic.  The metallic taste in tap water resuls from rusting ductile iron pipe.  A faint plastic taste will eventually show up in old bottled water.  Harmless but annoying.  There is no telling what contaminants can enter the recycling stream in post-consumer reprocessed plastic.  For this reason, reprocessed plastic is not an option for food or pharmaceutical packaging.  There is one exception - polyethylene terephthalate ( PET #1 ) which is re-polymerized vis-a-vis reprocessed, 

Commodity plastics such as polyethylene ( PE ), polypropylene (PP) and polystyrene ( PS ) are popular choices for food grade packaging because they are so inert.  For reasons still unknown, some polymers transfer taste to specific products.  For example, anyone who has made institutional milk bags knows there is zero tolerance for EVA.  The bouquet of EVA ( best described as apple vinegar ) transfers to milk.  

The subjective zone often results in vicious disputes.  Years ago, a major manufacturer of cereal detected an oxidized odor in the film yet there was no transfer to the product and there were no consumer complaints.  The film supplier had to make sandwiches out of the returned film because the cereal manufacturer refused to pay the invoice.

After 40 years and millions of pounds of ice bag film, we no longer make film for ice bags due to subjective, specious odor and taste complaints. 

Of course, very real leaching can ruin entire lot of product by the presence of only trace amounts.  Many a lot of circuit boards has been ruined by a few hundred parts per million of slip or silicone. Clean room packaging has zero tolerance for slip and silicone.

The threshold of parts per million has very serious legal implications, mainly about compliance with regulations. California prop 65 is not going away.  The scope is expanding indefinitely.  

Extractables encompass everything from the monomer itself to residual catalysts and additives.  So let's break it down:

monomers  Plastic is made from simple hydrocarbons.  With the exception of PVC, these feedstocks have been shown to be inert and harmless.  Old fashioned HDPE is still a popular choice for distilled water.

catalysts are necessary to facilitate a reaction to create the polymer chains.  The catalyst is either transformed or used up.  Remember the hysteria over BPA ?  Turns out it might have been overblown.  
Like it or not, the catalyst BPA is here to stay.  If BPA is an indisputable carcinogen, we should discontinue the use of ubiquitous 5 gallon polycarbonate carboys today.

Additives is a big subcategory encompassing antioxidants, stabilizers, antiblock, slip and pigments.   Additives each have a specific job to do.  Without antioxidants, plastics would have an odor like the smoke from a candle which was just extinguished.  Consumers would return any food packaged in an "antioxidant free" package.  Most resin antioxidants are tocopherols commonly known as vitamin E.  Only PVC has phthalates for stabilization.  

Antiblock is diatomaceous earth.  It is so inert it is used to encapsulate nitroglycerin to make dynamite.

Slip is used to make plastic slippery as the name implies.  Most slip additives anymore are pure enough that they can be Kosher certified.  

Most US made pigments are HMF, or "heavy metal free" if the end use is food packaging or anything medical.   The yellow does not contain lead and the orange no longer contains molybdenum. But most consumers prefer to eagerly expose themselves daily to dermal exposure to levels of lead which are in direct violation of CA prop 65.  

Quantifying leachables and extractables is done according to ASTM WK43975.  The extraction test is done in two solvents.  The extractables must fall below specific threshold amounts to be considered FDA approved.  

Of course, what is difficult to capture is goodwil and good faith.  If somebody is looking for an excuse to not pay their bill, odor and taste is a handy excuse.  As many injection molders found out ( some were put out of business ), the test method of CA prop 65 was modified to obtain the desired lead threshold results.  Whether or not the thresholds posed a realistic health hazard was irrelevant.  

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Topics: leachables & extractables, toxic plastic

EPR Extended Producer Responsibility - You will pay, not producers

Posted by Joel Longstreth on Thu, Jun 04, 2015 @ 06:08 PM

Extended Producer Responsibility ( EPR ) and product stewardship are ideas which are gaining traction globally.  Vilifying corporations may be satisfying to NGO's but the expense of recovery will be passed along to the consumer.  

 

 

The logic is that a corporation must be responsible for the entire life cycle of a product all the way to final disposal at end-of-life ( Germany holds the manufacturer legally responsible for the entire life cycle of the product under what is called "comprehensive outcome" ).  This would include re-use, take back and/or recycling. Problem: this costs money which is not presently included in the cost of the item.  Now the consumer pays for only the cost of the item hopefully produced with a small profit and quite possibly at loss. There is simply not enough profit built in to absorb these additional costs.  Packaging does not have a secondary use and cannot be repurposed.  

Container deposit legislation shows the consumer that recycling and recovery costs are extra.

The cost of disposing of toxins is often included in the sale price of some items.  Extending this principle to inert, non-toxic plastics is a bit of a stretch.  Just my opinion.  Container deposit legislation shows the consumer that recycling costs more than the container by itself.

Follwing the logic, the plastic processors are responsible for the behavior of the consumer who chooses to litter instead of recycling.  2 out of 3 containers made from #1 PET, the most recyclable of all polymers, end up as litter or landfill despite the best efforts of large corporations to encourage recycling.

Crafting EPR legislation might get complicated.  How would the cost be allocated ?  How much should the resin manufacturer be responsible for and how much for the processor ?  So-called "triple bottom line" concepts such as environmental full cost accounting ( EFCR ) and true cost accounting ( TCA ) attempt to capture the costs of the entire life cycle. They are open-ended and subjective at best.

file:///C:/Users/Joel%20Longstreth/Downloads/EPR_Packaging-Fact-Sheet.pdf

If the blame for plastic waste gets shifted to us plastic straw men, reality is the consumer will ultimately pay. Just as corporations pass along the costs of taxes, the plastic industry will pass these costs along.  

 update January 14, 2019

Look who's paying the sugar tax in Seattle.

 

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Topics: EPR, extended producer responsibility

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