Brentwood Plastics blog

Poly Film Industry Consolidation

Posted by Joel Longstreth on Wed, Sep 14, 2016 @ 03:19 PM

Like any industry which matures, there is first a dynamic growth curve followed by the inevitable consolidation wave.  The blown PE film business is both consolidating and contracting.


By the 1920's, there was a proliferation of automobile manufacturers in the thousands.  Aerospace didn't have
thousands of airplane manufacturers, but maybe hundreds.  An early map of the Kimberley mine was complex
with stakes by numerous colorful characters.  They are all whittled down to a handful of players.

Back in the 1950's, the commercial viability of blown PE film was uncertain.  Before our founder Joe Longstreth
established Brentwood Plastics in 1961, he sold PE resin by setting up companies from scratch to make LDPE film to take away market share from old fashioned true cellophane.  

Cut to present day.  The number of PE film outfits worldwide is certainly in the thousands.  "Turn-Key" film lines are ubiquitous.  Back in the early days, we bought the components separately and made some of the parts ourselves.  My grandfather designed a surface winder for narrow width tubing from scratch which is still in service.

In the US, the consolidation phase has been going on for decades.  The largest instituional trash can liner manufacturer is actually an amalgamation of formerly regional players.  You can't argue with the success of Sigma group's strategy of expansion by acquisition of financially distressed extruders.  By contrast, the largest manufacturer of private-label trash bags is Poly-America who has grown dramatically mostly by organic growth. 

Berry Plastics' mega merger with AEP is the latest chapter in consolidation of companies with roots going back to the 1970's.  Armin Kaufman, founder of Armin Films sold out to Tyco who unloaded their film maker portfolio to Berry in 2005. Berry merged with another large bankrupt player who had gone bankrupt in 2009 - Pliant.  

Where is Armin Kaufman now ?  In Hillside, NJ where he founded Hillside Plastics with the proceeds from the Tyco sale in direct competition.

To take stock, we compiled a list of US operations which include polyethylene blown film extrusion with apologies to anyone we overlooked ( call us if you want to be included ).  There was no clear trend.  A lot of old names were gone either due to buyouts or going out of business ( this is a capital-intensive business; the tripling of resin cost since the mid 90's has weeded out players with inadequate working capital ).  Many have vertically integrated blown film in their operations.  Some niche players were unchanged, some have developed into giants. Next Generation films is an extreme example.

We have been there / done that selling out thing back in 1984, probably not going back there for a while.  We believe there is enough demand for an old school, handcrafted monolayer operation.

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Topics: pe film

Plastic Film Thickness Variation

Posted by Joel Longstreth on Tue, May 22, 2012 @ 12:25 PM

While plastic film made by the blown film process can be controlled closely, there are limitations imposed by the interdependent factors of the process and plastic resin selection.

IMAG0153 resized 600

To understand the physics of the blown film process, think soap bubble blown vertically.  When the bubble starts out, the wall is thick and stable.  When it gets larger, the wall is thinner and starts shaking.  The relationship between the bubble size and the circular die, or aperture that the melt exits from, is a key factor called blow up ratio or BUR for short.  Gauge profile is easiest to control at low blowup ratios.  Problem: PE film made with a low blowup ratio can be weak and exhibit the dreaded straight line tear which results from too much orientation in the machine ( MD ) direction.  While the textbook happy spot is a blowup ratio of 2:1 ( bubble diameter = twice die diameter ), this is not always possible in the real world.  If scheduling realities dictate a higher blowup ratio, the operator must use tricks of the trade to achieve a flat, even plastic film.

The other component is resin selection.  Resins with higher viscosities or lower melt index, or "MI" for short, lend themselves to an even thickness profile. 

Of course, in the real world not every plastic film can be made from a very low preferably "fractional melt index" resin at a low blowup ratio.  Ironically the least critical blown film application - shrink film - is made with low melt index, low blowup ratio.  Anymore blown film plant managers are chefs who manage what winemakers call cuvees, or blends, of resins.

PE film with excessive variation is maddening when heat sealing and laminating.  "Baggy film" is a perennial complaint which will bounce a roll of film a country mile without hesitation.

There is a fundamental difference between point-to-point thickness variation and what is known in the converting industry as Yield or area derived from a specific weight.  Here are PE film conversion factors in both English and Metric units:

A good starting point for agreeing on thickness variation is the Flexible Packaging Association spec B 11.  Sorry, we can't link to it.  You have to buy a copy.

Over the years the capital equipment manufacturers have endeavored to make blown film lines which guarantee + - tight tolerances with non-adjustable features which take the operator variable out of the equation.  For now these luxury store bought turnkey lines are too rich for our blood. 

We can't help believe blown film is still an art and the operator should take responsibility for his workmanship. It is our tradition that every roll we make has the operator's ( or should we say artists ?) name on it.

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Topics: blown film, pe film, LDPE film, blown film extrusion, plastic film properties, plastic film

PE films - Why is PE film so inconsistent ?

Posted by Joel Longstreth on Mon, Dec 12, 2011 @ 02:06 PM

dreamstime xs 20504791 resized 600                                        Polyethylene blown film does not have to be inconsistent. 

If your low priced PE film is inconsistent within the same lot, your blown film supplier probably has used off-grade resins to save money on their major cost: PE resin.  The thinking is "the customer won't know the difference."  You do know the difference because the film doesn't seal or shrink like it did 2 hours ago after you readjusted the packaging machine settings for the third time today.  You could deal with it if the film was just consistent within the same pallet.  

Shrink film is a favorite dumping ground for extruders.  Just about any PE resin will shrink, so it's tempting to blend in repro and literally floorsweep.

Problem:  If you are buying printed film, laminations or bags, you are at least one step removed from the film supplier.  You have no way of knowing if you are getting film from the same source every time.  Even if the film does come from the same source, there is a good chance their extruder has switched resins to lower cost.

You don't have to live like this.  When you get sick of it, give us a chance to prove continuity of supply in blown film is available.

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Topics: pe film, plastic sheet film, LDPE film, poly film, polyethylene films

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