November 9, 2023 • 21 mins
What really happens when we use recycled plastics for injection molded parts? This question has sparked much debate, and in this enlightening episode, we take you on a journey through the life cycle of injection molding plastics. We'll expose the reasons behind the industry's mistrust of recycled materials, the quality inconsistencies, and the environmental factors that are causing this skepticism.
Ever wondered about the challenges of using recycled plastics in injection molding? We've got you covered. We'll scrutinize the need for greater control in the recycling process, the design changes OEMs need to consider, and the potential of downcycling parts from the recycled stream. We'll also illuminate the crucial role of testing methods in predicting the quality of injection molded parts made from recycled materials. This episode promises a deep understanding of the interplay between the plastics and automotive industry, and the future of recycled materials.
Bozilla Corporation is a plastics consulting and optimization company focusing on plastic injection molding. We invite you to visit our website to learn more about our services and how we can successfully contribute to your project.
www.BozillaCorp.com
Linkedin- connect with Chris
800-942-0742
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Transcript
Episode Transcript
Available transcripts are automatically generated. Complete accuracy is not guaranteed.
Chris Czeczuga (00:03):
I am Chris Czeczuga and welcome to the
Plastic Pro Insights podcast.
I am a degree Plastics engineerand have been a consultant in
the plastics industry for over20 years, with a primary focus
on injection molding.
I'm excited to share myknowledge about plastics and
their applications, from thechemical level up to the final
performance level.
My work includes consultingoptimizing optimizing plastic
(00:24):
parts and injection molds.
I employ root cause analysismethods and am I'm a certified
expert in the Autodesk mold flowsoftware.
I have created this podcast tohelp educate people in all
facets of the plastics industry.
So let's get started.
Welcome to our first episode ofPlastics Pro Insights.
Today, I Today will talk aboutthe viability of utilizing
(00:45):
recycled plastics for injectionmolding, specifically in the
automotive industry.
Recently I was at the automotiveTPO conference in Michigan.
There were a lot of OEMs there,tier ones, material suppliers,
and many others from theindustry, and it was a great
opportunity to capture theattention of all of these folks,
(01:06):
many of whom I've worked with.
There was a heavy focus onutilizing more recycled content.
One of the primary discussionswas about how to push the
industry to adopt utilizing morerecycled materials in the
injection molding process, insome cases even up to 100%
recycled content whenever theycould.
I had the opportunity topropose some of my learnings
(01:30):
from my experience with themolders and how the folks on the
floor have recently offeredtheir opinions on the subject.
When I've worked with them andreceived their feedback, I've
learned that they really don'ttrust the recycled materials,
which was very interesting.
Because what's trust when youcome to injection molding?
Well, trust is about being ableto make consistently good parts
(01:54):
on the floor.
If your process is consistentand trustworthy, then you're
going to be making good,consistent parts.
Unfortunately, they don't trustthese recycled materials
because the recycled materialsare not consistent, therefore
their process isn't consistent.
And if their process isn'tconsistent, they can't control
the quality of their parts.
(02:14):
As soon as they recognize that,they just immediately don't
want to use it.
I shouldn't say it, but theyjust throw away that recycled
material.
They don't even use it.
They try to use the leastamount of the recycled material,
but most of the time, becausethey can't trust it, they'll
simply not use it at all andjust stick to the virgin resin.
(02:36):
I thought this discussionwould be a good opportunity to
create this podcast so we candiscuss it and take a deep dive
into the life cycle of recycledmaterials as it relates to the
injection molding industry.
Let's dive into the life cycleof injection molding plastics,
from molding the part right upto the field use and the
(02:58):
reclamation process and back tothe injection molding process.
Let's look at this life cycle.
To start off, the plastic goesthrough the injection molding
process and the injectionmolding process can impact the
quality and the properties ofthe plastic.
If you think about it, theplastic enters the injection
molding machine and hits thescrew.
(03:19):
The screw starts spinning,grinds up the plastic, the
plastic starts getting beaten upby the screw itself and it
starts to experience somethermal heating.
There'll be thermal cycling andabuse and with both of these,
and the molecules of the plasticcan get broken.
And when we talk about themolecules, the length of the
(03:42):
overall starting molecule is themolecular weight and whenever
that chain is broken through oneof these processes.
This abuse, that is what we'llcall the molecular weight
reduction, and that molecularweight reduction is actually
polymer degradation.
After the polymer goes throughthe injection molding process,
(04:08):
and the makes the part.
That's the best qualityexperience of the material- the
least broken down, the leastbeat up, so you get the best
quality part, best properties,both when it comes to the
chemical properties, themechanical properties.
That's your best part.
(04:31):
Now let's say the part is gonethrough its useful life and it
starts the reclamation process.
Well, what happens in thatreclamation process?
If it's a part of a vehicle andit goes to a scrap yard and the
parts pulled out?
Where's the part?
(04:52):
Is it indoors?
Is it outside somewhere?
What environmental factors isit exposed to?
Does the consumer rip off maybea fascia and they use it on
another car and it goes throughthe second process, where it's
being exposed to UV, moretemperature cycles and changes,
(05:16):
or even chemical exposure.
In the automotive industrythere's a lot of chemical
exposure.
You've got fuels, chemicalslike brake fluid, gasoline.
You got diesel.
You've got radiator fluid,you've got the salt and
(05:36):
corrosive environment of theharsh winters and those kinds of
climates, again, the thermalcycling.
Your vehicle sitting in aparking lot right up to once
it's been reclaimed, is it justsitting out in the fields and
being exposed to the sun, day inout different seasons, and so
on?
What are we looking at here?
(05:59):
What exactly does the customerdo with the products?
Maybe it goes in the trash binand goes right to the dump.
For a vehicle that might not bethe case.
It'll probably get reclaimed bysome recycling scrap yard and
such, and then you have to beconcerned about whether or not
it's been indoors or outdoors,but nevertheless it's seeing
(06:21):
some exposure to some breakdown.
That recycling experience iswhat we're talking about.
Does that part now get picked upand go through a sorting
process?
A sorting process is simplyjust taking it and putting it in
its appropriate location or bin.
That's fairly benign.
But you have now anotherprocess the cleaning process.
(06:45):
Now the cleaning process can bethermal or chemical and either
one is going to create somedegradation, breakdown of the
polymer.
When we look at chemicalexposure for cleaning and so on,
you want to remove anyadhesives and you want to remove
any oils and byproducts on thatpart.
(07:06):
It's cleaned with chemicals.
Then there's also the thermalprocess that's also used, like
if it's a hot chemical bath orwater bath, that'll remove any
adhesives.
There's steam treatments andthen you have the drying and
sanitation process more and morethermal exposure and thermal
(07:29):
cycling.
Finally, during thisreclamation process, you're
going to grind up these parts.
Once they're sorted, separated,cleaned, you have to go through
grinding.
Grinding reminds me of what anold professor has told me is
it's bastardized as the material.
I know that's a crazy term, butit just beats and pulverizes
(07:53):
that material.
It's going to go through anexcruciating process during the
recycling process.
When it's ground up like that,it's further degraded its
quality, the materials now inits recycled form and it's ready
to ship to the moldingfacilities.
Understanding how recycling hasan impact on the quality of the
(08:15):
polymer is extremely important.
When we talk about thisdegradation, what does it mean?
Well, on a chemical level, as aplastics engineer, we refer to
that as chain scission.
That's when those molecules,the molecular weight, is broken
and the chains become smaller.
Now what happens when a chainbecomes smaller?
(08:36):
That's a lower molecular weight.
So when it is lower, the chainsdon't entangle as much and they
flow easier because there'sless entanglement, so that lower
molecular weight equals lowerviscosity, so it flows easier.
But when you have lowermolecular weight you have a loss
(09:00):
of properties.
It impacts strength, toughness,transition changes and so on.
This discussion about molecularweight this is the big
discussion, because you want tobe able to control the quality
of this material, ie themolecular weight.
And there's two things to thinkabout with molecular weight.
(09:21):
That's the variation anddistribution.
You want to not have a wholelot of variation in your
molecular weight.
You want it to be if you thinkabout the Gaussian curve or the
Bell curve you want it to beunder a certain part of that
Bell curve so you can controlthat molecular weight
(09:42):
distribution.
And that's critical.
The big question, theoutstanding question I have for
the industry and I've beenreally confronted when faced
with here is how does therecycling process, how does the
recycling industry control theirproduct?
How do they control thatmolecular weight variation and
(10:05):
distribution?
Because that's going to haveyour impact on the polymers
properties, ie part properties.
We have to think about thisquality control.
How do you control themolecular weight variation
distribution?
How do you test for it?
Even bigger?
I mean, if you're going tocontrol it, you have to know how
(10:26):
to test it and what happenswhen you can't control it, which
is the case that we are livingin right now.
Now there might be somerecyclers in the industry who
claim that they are controllingit, and I've had actually
somebody come up to me, multiplepeople come up to me and say,
(10:46):
well, it is controlled.
And I asked them well, what doyou mean controlled?
Do you actually test thematerial?
And they say, yeah, we havetest methods and by that, most
times their testing methods, asI've learned, are the MFR.
Now, the MFR, the Melt FlowRheology, or MFI, Melt Flow
(11:08):
Index.
It's a single data pointviscosity test.
It's a zero shear viscositytest, so it doesn't represent
the actual experience that thematerial is going to go through
during the injection moldingprocess.
It's close to zero shear.
So they're basically saying thematerial is going to flow this
amount over this time periodwith almost no shear experience.
(11:33):
So it's not a fair test.
It doesn't capture theviscosity over a shear rate
experience.
In order to properly capturematerial, you can do it one of
two ways.
Use the dual capillaryrheometer, which is a
traditional method.
It's a little bit more of alengthy process, but it uses a
(11:57):
benchmark capillary versus achanged capillary, so you can
actually test the material overa wide range of shear experience
, a wide shear rate range, andthen you can really capture
exactly what that material isdoing.
What they can also do, theother test method is an
(12:18):
instrumented injection moldingmachine with a slit die.
That is the most comprehensiveway to test material and that
way is the best.
If you're going to do any kindof flow simulation, you have to
capture all the mechanicalproperties, the PVT properties
and, most importantly, therheology, that shear rate curve
(12:42):
that we're talking about, thatviscosity versus shear rate.
The big thing that reallystrikes me is if you're going to
recycle, you have to be able tocontrol your material.
You have to test it.
Now, if you test it, are youcontrolling it?
No, you're just learning thatyour material has this kind of
(13:05):
viscosity.
Well, this batch has this kindof viscosity.
Well, what about the next batch?
Well, all of these plastic partshave come from different
locations, different experiencesand they're going to have
different molecular weights.
There's going to be atremendous amount of variation.
How do you control that?
(13:26):
You really have to go upstreamand start with as soon as a
vehicle hits its end of life.
Just as an example, let's justsay that the OEM reclaims that
vehicle and they take the partsout.
(13:48):
Now they can control all thoseplastic parts in a recycling
stream, so they can control thethermal experience or the
mechanical degradationexperience, the chemical
exposure, and create a moreconsistent breakdown, molecular
breakdown, of the material.
If they have that kind ofcontrol.
(14:09):
Most likely you're going to beable to control your molecular
weight variation, but right nowwe're counting on third party
reclamation people who reclaimedmaterials for the reclamation
process.
So we've got to make sure that,even though we're testing the
(14:29):
materials, we know what we'reactually testing for.
Okay, so until they get acontrol over the actual
experience of these parts theexperience meaning the thermal
experience, the chemicalexperience, the mechanical
(14:49):
experience the existing solutionthat they're using is going to
be used and that's not going tobe accepted in the industry.
It's just not.
And fortunately I have to speakthe truth here because of what
I've learned in order for theguys on the floor to trust these
recycled materials, they haveto be consistently controlled
(15:14):
and have to be high qualityresins, and we're just not
seeing that right now, which isthe whole point of this podcast.
So if we can get that controlof the molecular weight and the
molecular weight variation,we're going to be able to use
more recycled materials.
Now, if there's not a way toget a great grasp, but we get
(15:38):
very close to it, we can startincorporating more of the
recycled resin and blending itwith the virgin material.
Because when you blend recycledmaterials, if it's really a
poor recycled material with atremendous variation and no
control.
So batch to batch to batch istotally different.
You can't use a whole lot ofthat recycled resin because
(16:01):
you're not going to have aprocess that's controllable on
your injection molding machine.
So you can only add a littlebit of that to the virgin resin
you know, and vaguely dilute thevirgin resin.
Now that virgin resin is goingto take over and you're going to
have control.
But if you start controllingyour recycled material, you can
add and incorporate it and blendmore of it in with your virgin
(16:25):
material.
So you'll be using morerecycled content.
And what I neglected to say andI did bring this up in a recent
meeting with a major OEM is theOEMs have to start designing
parts for recycled resins.
Now what's that mean, designingparts for recycled resins?
(16:47):
Well, certain parts are incertain areas of the vehicle
that are less seen, less class Asurface in the industry terms.
So if they are like a fasciabracket and under the hood
bracket, let's just say bracket,something that needs good
mechanical control.
But you know it doesn't.
It can warp a little bit.
(17:09):
The glass transition is notcritical, it's just basically
holding something in place.
It doesn't have to be, you know, aesthetically pleasing at all.
So you can use more recycledmaterials, maybe up to 100% if
it's quality recycled resin oncertain parts like that.
And then, once again, if the OEMlet's just say, reclaims the
(17:31):
car at the end of life andcontrols that recycled process,
then they can take those parts,put them in their recycle loop
and utilize certain partscontrolling a recycled process
for certain applications.
So the second recycled pathway,so the downcycling of that part
(17:53):
is again used in a car, butjust in a different location for
a different purpose.
We can do that until the resinis just totally beat to crap and
you can then use it to makeplastic lumber or car stops in
the parking lot, just thingsthat you still don't have to
throw the polymer away.
(18:14):
It still has a use.
But it cannot be used in theautomotive industry just because
it's just been beat up too much.
So you have to be able torecycle it, capture it into your
recycle loop, but then alsomaybe stamp or keep control on
the part revealing how manytimes it has experienced
recycling.
Once it's been degraded to apoint it can't be used at all
(18:36):
anymore.
It's just no good.
So the big focus here is onthis reclamation process.
To summarize this wholediscussion, using recycled
plastics is currentlychallenging.
It's challenging because it'sgot variation in molecular
weight which affects the processcontrol and part quality.
(18:58):
It's difficult to ensure theconsistency of that recycled
material and the lack ofknowledge about the materials
history leads tounpredictability.
So this material is just outthere, whether it's in a vehicle
or somewhere else.
Is the consumer reclaiming it?
Is it going through a thirdparty?
What are they doing to thematerial?
(19:20):
Its history is veryunpredictable and unknown and
that history needs to becaptured to create this control.
Once it's captured and there iscontrol, there has to be good
existing test methods.
More of the industry is relyingon flow analysis and without
proper testing, flow analysiscannot predict properly.
(19:43):
So there has to be good processtest methods in order to run
flow analysis that haveconfidence in prediction, like
warpage and quality prediction,as well as having the confidence
in processing.
So that brings us to the end ofthis podcast and I think this
is a very important topic andit's going to be challenging and
(20:04):
I'm sure this topic is going toresurface many times after this
podcast and I'll do follow-upsas things go on, but right now
I'm really pushing the industry,and by pushing I mean just
mentioning, like this podcast,to everyone that we need to be
able to control this recyclingprocess and then control the
test methods so that everybodyin the engineering group and
(20:29):
processing group, everybody onthe whole production stream has
confidence and is willing to usethese recycled materials.
So thank you for your timetoday.
Carol Dorsey (20:39):
We hope you have enjoyed this episode of Bozilla
Corporation's Pro Insightpodcast Plastics Engineers
Discussing Plastics.
Bozilla Corporation is aplastics consulting firm which
offers injection molding,engineering, consulting and
optimization.
For more information, we inviteyou to visit our website, www.
(21:03):
BozillaCorp.
com.
I am Chris Czeczuga and welcome to the
Plastic Pro Insights podcast.
I am a degree Plastics engineerand have been a consultant in
the plastics industry for over20 years, with a primary focus
on injection molding.
I'm excited to share myknowledge about plastics and
their applications, from thechemical level up to the final
performance level.
My work includes consultingoptimizing optimizing plastic
(00:24):
parts and injection molds.
I employ root cause analysismethods and am I'm a certified
expert in the Autodesk mold flowsoftware.
I have created this podcast tohelp educate people in all
facets of the plastics industry.
So let's get started.
Welcome to our first episode ofPlastics Pro Insights.
Today, I Today will talk aboutthe viability of utilizing
(00:45):
recycled plastics for injectionmolding, specifically in the
automotive industry.
Recently I was at the automotiveTPO conference in Michigan.
There were a lot of OEMs there,tier ones, material suppliers,
and many others from theindustry, and it was a great
opportunity to capture theattention of all of these folks,
(01:06):
many of whom I've worked with.
There was a heavy focus onutilizing more recycled content.
One of the primary discussionswas about how to push the
industry to adopt utilizing morerecycled materials in the
injection molding process, insome cases even up to 100%
recycled content whenever theycould.
I had the opportunity topropose some of my learnings
(01:30):
from my experience with themolders and how the folks on the
floor have recently offeredtheir opinions on the subject.
When I've worked with them andreceived their feedback, I've
learned that they really don'ttrust the recycled materials,
which was very interesting.
Because what's trust when youcome to injection molding?
Well, trust is about being ableto make consistently good parts
(01:54):
on the floor.
If your process is consistentand trustworthy, then you're
going to be making good,consistent parts.
Unfortunately, they don't trustthese recycled materials
because the recycled materialsare not consistent, therefore
their process isn't consistent.
And if their process isn'tconsistent, they can't control
the quality of their parts.
(02:14):
As soon as they recognize that,they just immediately don't
want to use it.
I shouldn't say it, but theyjust throw away that recycled
material.
They don't even use it.
They try to use the leastamount of the recycled material,
but most of the time, becausethey can't trust it, they'll
simply not use it at all andjust stick to the virgin resin.
(02:36):
I thought this discussionwould be a good opportunity to
create this podcast so we candiscuss it and take a deep dive
into the life cycle of recycledmaterials as it relates to the
injection molding industry.
Let's dive into the life cycleof injection molding plastics,
from molding the part right upto the field use and the
(02:58):
reclamation process and back tothe injection molding process.
Let's look at this life cycle.
To start off, the plastic goesthrough the injection molding
process and the injectionmolding process can impact the
quality and the properties ofthe plastic.
If you think about it, theplastic enters the injection
molding machine and hits thescrew.
(03:19):
The screw starts spinning,grinds up the plastic, the
plastic starts getting beaten upby the screw itself and it
starts to experience somethermal heating.
There'll be thermal cycling andabuse and with both of these,
and the molecules of the plasticcan get broken.
And when we talk about themolecules, the length of the
(03:42):
overall starting molecule is themolecular weight and whenever
that chain is broken through oneof these processes.
This abuse, that is what we'llcall the molecular weight
reduction, and that molecularweight reduction is actually
polymer degradation.
After the polymer goes throughthe injection molding process,
(04:08):
and the makes the part.
That's the best qualityexperience of the material- the
least broken down, the leastbeat up, so you get the best
quality part, best properties,both when it comes to the
chemical properties, themechanical properties.
That's your best part.
(04:31):
Now let's say the part is gonethrough its useful life and it
starts the reclamation process.
Well, what happens in thatreclamation process?
If it's a part of a vehicle andit goes to a scrap yard and the
parts pulled out?
Where's the part?
(04:52):
Is it indoors?
Is it outside somewhere?
What environmental factors isit exposed to?
Does the consumer rip off maybea fascia and they use it on
another car and it goes throughthe second process, where it's
being exposed to UV, moretemperature cycles and changes,
(05:16):
or even chemical exposure.
In the automotive industrythere's a lot of chemical
exposure.
You've got fuels, chemicalslike brake fluid, gasoline.
You got diesel.
You've got radiator fluid,you've got the salt and
(05:36):
corrosive environment of theharsh winters and those kinds of
climates, again, the thermalcycling.
Your vehicle sitting in aparking lot right up to once
it's been reclaimed, is it justsitting out in the fields and
being exposed to the sun, day inout different seasons, and so
on?
What are we looking at here?
(05:59):
What exactly does the customerdo with the products?
Maybe it goes in the trash binand goes right to the dump.
For a vehicle that might not bethe case.
It'll probably get reclaimed bysome recycling scrap yard and
such, and then you have to beconcerned about whether or not
it's been indoors or outdoors,but nevertheless it's seeing
(06:21):
some exposure to some breakdown.
That recycling experience iswhat we're talking about.
Does that part now get picked upand go through a sorting
process?
A sorting process is simplyjust taking it and putting it in
its appropriate location or bin.
That's fairly benign.
But you have now anotherprocess the cleaning process.
(06:45):
Now the cleaning process can bethermal or chemical and either
one is going to create somedegradation, breakdown of the
polymer.
When we look at chemicalexposure for cleaning and so on,
you want to remove anyadhesives and you want to remove
any oils and byproducts on thatpart.
(07:06):
It's cleaned with chemicals.
Then there's also the thermalprocess that's also used, like
if it's a hot chemical bath orwater bath, that'll remove any
adhesives.
There's steam treatments andthen you have the drying and
sanitation process more and morethermal exposure and thermal
(07:29):
cycling.
Finally, during thisreclamation process, you're
going to grind up these parts.
Once they're sorted, separated,cleaned, you have to go through
grinding.
Grinding reminds me of what anold professor has told me is
it's bastardized as the material.
I know that's a crazy term, butit just beats and pulverizes
(07:53):
that material.
It's going to go through anexcruciating process during the
recycling process.
When it's ground up like that,it's further degraded its
quality, the materials now inits recycled form and it's ready
to ship to the moldingfacilities.
Understanding how recycling hasan impact on the quality of the
(08:15):
polymer is extremely important.
When we talk about thisdegradation, what does it mean?
Well, on a chemical level, as aplastics engineer, we refer to
that as chain scission.
That's when those molecules,the molecular weight, is broken
and the chains become smaller.
Now what happens when a chainbecomes smaller?
(08:36):
That's a lower molecular weight.
So when it is lower, the chainsdon't entangle as much and they
flow easier because there'sless entanglement, so that lower
molecular weight equals lowerviscosity, so it flows easier.
But when you have lowermolecular weight you have a loss
(09:00):
of properties.
It impacts strength, toughness,transition changes and so on.
This discussion about molecularweight this is the big
discussion, because you want tobe able to control the quality
of this material, ie themolecular weight.
And there's two things to thinkabout with molecular weight.
(09:21):
That's the variation anddistribution.
You want to not have a wholelot of variation in your
molecular weight.
You want it to be if you thinkabout the Gaussian curve or the
Bell curve you want it to beunder a certain part of that
Bell curve so you can controlthat molecular weight
(09:42):
distribution.
And that's critical.
The big question, theoutstanding question I have for
the industry and I've beenreally confronted when faced
with here is how does therecycling process, how does the
recycling industry control theirproduct?
How do they control thatmolecular weight variation and
(10:05):
distribution?
Because that's going to haveyour impact on the polymers
properties, ie part properties.
We have to think about thisquality control.
How do you control themolecular weight variation
distribution?
How do you test for it?
Even bigger?
I mean, if you're going tocontrol it, you have to know how
(10:26):
to test it and what happenswhen you can't control it, which
is the case that we are livingin right now.
Now there might be somerecyclers in the industry who
claim that they are controllingit, and I've had actually
somebody come up to me, multiplepeople come up to me and say,
(10:46):
well, it is controlled.
And I asked them well, what doyou mean controlled?
Do you actually test thematerial?
And they say, yeah, we havetest methods and by that, most
times their testing methods, asI've learned, are the MFR.
Now, the MFR, the Melt FlowRheology, or MFI, Melt Flow
(11:08):
Index.
It's a single data pointviscosity test.
It's a zero shear viscositytest, so it doesn't represent
the actual experience that thematerial is going to go through
during the injection moldingprocess.
It's close to zero shear.
So they're basically saying thematerial is going to flow this
amount over this time periodwith almost no shear experience.
(11:33):
So it's not a fair test.
It doesn't capture theviscosity over a shear rate
experience.
In order to properly capturematerial, you can do it one of
two ways.
Use the dual capillaryrheometer, which is a
traditional method.
It's a little bit more of alengthy process, but it uses a
(11:57):
benchmark capillary versus achanged capillary, so you can
actually test the material overa wide range of shear experience
, a wide shear rate range, andthen you can really capture
exactly what that material isdoing.
What they can also do, theother test method is an
(12:18):
instrumented injection moldingmachine with a slit die.
That is the most comprehensiveway to test material and that
way is the best.
If you're going to do any kindof flow simulation, you have to
capture all the mechanicalproperties, the PVT properties
and, most importantly, therheology, that shear rate curve
(12:42):
that we're talking about, thatviscosity versus shear rate.
The big thing that reallystrikes me is if you're going to
recycle, you have to be able tocontrol your material.
You have to test it.
Now, if you test it, are youcontrolling it?
No, you're just learning thatyour material has this kind of
(13:05):
viscosity.
Well, this batch has this kindof viscosity.
Well, what about the next batch?
Well, all of these plastic partshave come from different
locations, different experiencesand they're going to have
different molecular weights.
There's going to be atremendous amount of variation.
How do you control that?
(13:26):
You really have to go upstreamand start with as soon as a
vehicle hits its end of life.
Just as an example, let's justsay that the OEM reclaims that
vehicle and they take the partsout.
(13:48):
Now they can control all thoseplastic parts in a recycling
stream, so they can control thethermal experience or the
mechanical degradationexperience, the chemical
exposure, and create a moreconsistent breakdown, molecular
breakdown, of the material.
If they have that kind ofcontrol.
(14:09):
Most likely you're going to beable to control your molecular
weight variation, but right nowwe're counting on third party
reclamation people who reclaimedmaterials for the reclamation
process.
So we've got to make sure that,even though we're testing the
(14:29):
materials, we know what we'reactually testing for.
Okay, so until they get acontrol over the actual
experience of these parts theexperience meaning the thermal
experience, the chemicalexperience, the mechanical
(14:49):
experience the existing solutionthat they're using is going to
be used and that's not going tobe accepted in the industry.
It's just not.
And fortunately I have to speakthe truth here because of what
I've learned in order for theguys on the floor to trust these
recycled materials, they haveto be consistently controlled
(15:14):
and have to be high qualityresins, and we're just not
seeing that right now, which isthe whole point of this podcast.
So if we can get that controlof the molecular weight and the
molecular weight variation,we're going to be able to use
more recycled materials.
Now, if there's not a way toget a great grasp, but we get
(15:38):
very close to it, we can startincorporating more of the
recycled resin and blending itwith the virgin material.
Because when you blend recycledmaterials, if it's really a
poor recycled material with atremendous variation and no
control.
So batch to batch to batch istotally different.
You can't use a whole lot ofthat recycled resin because
(16:01):
you're not going to have aprocess that's controllable on
your injection molding machine.
So you can only add a littlebit of that to the virgin resin
you know, and vaguely dilute thevirgin resin.
Now that virgin resin is goingto take over and you're going to
have control.
But if you start controllingyour recycled material, you can
add and incorporate it and blendmore of it in with your virgin
(16:25):
material.
So you'll be using morerecycled content.
And what I neglected to say andI did bring this up in a recent
meeting with a major OEM is theOEMs have to start designing
parts for recycled resins.
Now what's that mean, designingparts for recycled resins?
(16:47):
Well, certain parts are incertain areas of the vehicle
that are less seen, less class Asurface in the industry terms.
So if they are like a fasciabracket and under the hood
bracket, let's just say bracket,something that needs good
mechanical control.
But you know it doesn't.
It can warp a little bit.
(17:09):
The glass transition is notcritical, it's just basically
holding something in place.
It doesn't have to be, you know, aesthetically pleasing at all.
So you can use more recycledmaterials, maybe up to 100% if
it's quality recycled resin oncertain parts like that.
And then, once again, if the OEMlet's just say, reclaims the
(17:31):
car at the end of life andcontrols that recycled process,
then they can take those parts,put them in their recycle loop
and utilize certain partscontrolling a recycled process
for certain applications.
So the second recycled pathway,so the downcycling of that part
(17:53):
is again used in a car, butjust in a different location for
a different purpose.
We can do that until the resinis just totally beat to crap and
you can then use it to makeplastic lumber or car stops in
the parking lot, just thingsthat you still don't have to
throw the polymer away.
(18:14):
It still has a use.
But it cannot be used in theautomotive industry just because
it's just been beat up too much.
So you have to be able torecycle it, capture it into your
recycle loop, but then alsomaybe stamp or keep control on
the part revealing how manytimes it has experienced
recycling.
Once it's been degraded to apoint it can't be used at all
(18:36):
anymore.
It's just no good.
So the big focus here is onthis reclamation process.
To summarize this wholediscussion, using recycled
plastics is currentlychallenging.
It's challenging because it'sgot variation in molecular
weight which affects the processcontrol and part quality.
(18:58):
It's difficult to ensure theconsistency of that recycled
material and the lack ofknowledge about the materials
history leads tounpredictability.
So this material is just outthere, whether it's in a vehicle
or somewhere else.
Is the consumer reclaiming it?
Is it going through a thirdparty?
What are they doing to thematerial?
(19:20):
Its history is veryunpredictable and unknown and
that history needs to becaptured to create this control.
Once it's captured and there iscontrol, there has to be good
existing test methods.
More of the industry is relyingon flow analysis and without
proper testing, flow analysiscannot predict properly.
(19:43):
So there has to be good processtest methods in order to run
flow analysis that haveconfidence in prediction, like
warpage and quality prediction,as well as having the confidence
in processing.
So that brings us to the end ofthis podcast and I think this
is a very important topic andit's going to be challenging and
(20:04):
I'm sure this topic is going toresurface many times after this
podcast and I'll do follow-upsas things go on, but right now
I'm really pushing the industry,and by pushing I mean just
mentioning, like this podcast,to everyone that we need to be
able to control this recyclingprocess and then control the
test methods so that everybodyin the engineering group and
(20:29):
processing group, everybody onthe whole production stream has
confidence and is willing to usethese recycled materials.
So thank you for your timetoday.
Carol Dorsey (20:39):
We hope you have enjoyed this episode of Bozilla
Corporation's Pro Insightpodcast Plastics Engineers
Discussing Plastics.
Bozilla Corporation is aplastics consulting firm which
offers injection molding,engineering, consulting and
optimization.
For more information, we inviteyou to visit our website, www.
(21:03):
BozillaCorp.
com.
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