plastic responses
Barnhart Prosthetics
Description
Collection
Title:
plastic responses
Creator:
Barnhart Prosthetics
Date:
5/2/2008
Text:
Hi, following is my question and then responses.
Hi,
Our regular plastic distributors have apparently switched their manufacturers,
or at least are getting lower quality plastics now. What we are seeing is
polypro that has a milky look to it, and in some cases never goes clear during
heating. This alone is not an issue, but the plastics are more flexible than in
the past. I think that they have more impurities in the plastic, that is making
it more flexible.
My question is: who has the most pure platics? I remember one of the
distributors claiming that they only had their plastic manufactured for O and P,
and was very pure.
Thanks,
Nathan Keepers, CPO
We had the same experience and were told it was the same product. So we switched to APS Allied plastics out of Texas. If you purchase more than $499 of plastic, shipping is free. Now, they have both types of plastics; you just need to let them know you need O&P grade and they will get the good old original polypro for you. Their number is 888-838-2287.
I use allied plastics in dallas texas.
Who are you using now? We use O&P Enterprises and don't have any issues at present
I am producer of all kinds of thermoplastic sheet for Orthosis . But I am student in Uk (PhD0 and my company is in Iran.
I get my plastic from a private company in Seattle called Port Plastic and we've had no problems and have not seen any changes except higher prices.
If you need their number, let me know. They ship by truck.
We use American Plastics and we have had no problems with there products.
Give Allied Plastics in Dallas a call, ask for Lisa Alston, I'm sure you
will be pleased with the quality of thier plastics
I am not sure who has pure plastic. But may I ask who was your supplier? Because today I actually had a problem at work with our 1 mm white polyethylene that we purchased from Pel Supply. I had a new piece and it shrivels up like a piece of bacon and never turned clear. Then,I found a square piece of our old 1 mm polyethylene and it heated perfect and even turned clear.
I don't know if it helps but we recently started getting plastic from American Plastics and its really good quality. If you use Otto Bocks Thermolyn Stief, call American Plastics they have the same exact plastic for less.
i have not used them, but guard industries in st louis claims they have very good plastic. i would like to try them but they are a bit more expensive than cope plastic and my manager won't let me switch. give them a try.
Hi Nathan,
Regarding pure plastic:
The definition of pure polypropylene as your are seeking is a very
subjective. Since we do not have a defined standard for orthopedic grade
polypropylene, there are numerous definitions fitting various end use
capabilities that are marketed as such.
Some of the orthopedic grade materials that is sold in O&P is classified
as FDA material. This material is usually a FDA food grade meaning that the
material can have contact with consumable food, and usually is used in
packaging for food. The thinking is if the material is good enough to eat
food from or for the storage and transportation of food, then it must be
good enough to be in contact with the human body.
The U.S. Food & Drug Administration (FDA) requires that plastics used in
food packaging be of greater purity than plastics used for non-food
packaging.
Food grade plastic does not contain dyes or recycled plastic deemed harmful
to humans. However, this does not mean that food grade plastic cannot
contain recycled plastic.( <URL Redacted>)
Of course if you think FDA food grade PP is pure take a look at the FDA
regulation:
<URL Redacted>
Westlake Plastics ( <URL Redacted>) does make a
medical grade polypropylene which they call Propylux HS2. It is used for
medical instrument trays that require sterilization. I have not seen this
extruded material used in O&P and quite frankly, it probably would be to
expensive for our needs and not be of the type of resin formula that would
be compatible with actual skin contact. Westlake also makes implantable
thermoplastic polymers, but that is an obvious unrelated application and
topic.
There are companies that advertise an orthopedic PP. Proteus® O&P Grade
Sheet is an example. Usually these are virgin grade materials, i.e., they
only contain virgin PP pellets, as they come from the resin manufacturer who
conducts the large scale polymerization of propylene gas into a solid, and
the various additive to make the finished resin compatible with the end use.
In the case of O&P, the resin first must be compatible with the extrusion
process and have a melt index to match the process for thermoforming. Just
remember, that there is no set standard for orthopedic grade so these
companies set their own standard for the product they are selling and thus
calling it orthopedic grade.
Although it is possible to formulate a pure polypropylene, it is usually
necessary to mix additives in with the basic resin. Additives ease the use
of PP for extrusion and UV additives are added for protection against
exposure to sunlight. If you took the time to read or scan the FDA link of
food grade, you saw that there are a multitude of additives that give PP
various characteristics. In essence a pure PP is hard to find.
The best means to assure a consistent supply of PP sheetstock to your lab is
to communicate with your sheet distributor to confirm that they always buy
the specific polymer type from an extruder who in turn is always using the
same resin from the PP producer. It is a three step process: distributor -
extruder - resin manufacturer. Your simple visual inspection of your
sheetstock indicated that there was some change in the material. Since the
material did not turn clear at melt temperature would indicate that there we
some additives in the PP resin, or it was a PP mixture that contained
regrind or another resin type entirely. PP will turn clear at melt
temperature as the molecular structure changes from a semi-crystalline
structure to an amorphous structure which allows visible light rays to
actual pass through the structure instead of refracting as it the case with
room temperature PP and it normal opaque appearance.
Polypropylene is a difficult material for use in our vacuum thermoforming
process due to its semi-crystalline chemical structure. Inconsistency in the
procurement of your raw sheetstock certainly does not help with even simple
lab process controls.
We have had the same experience with the aded problrm of our braces were cracking as we began to cut them off the mold. there seemed to be tension maybe because of inadequate stress relief.
I used to be in the plastics business. The plastic you describe is a Poly-Hi solidur product. The milky white appearance you are describing is an optical whitening additive (think bright white). It's not particularly bad or good, just different. I sold lots of Poly-Hi material into O&P accounts ten years ago. There really isn't an O&P plastic, although some manufacturers' products are marketed as such. The O&P market is too tiny to sustain specific production (despite what people may say). Pure or virgin plastic is a myth, every manufacturer slips a bit of regrind into their products (I've been to the plants), some more than others. The key is start tracking your distributor's brand of plastic. Different manufacturers use different resins, and some are more suited to O&P. It is both the resin used and the quality of the manufacturing process that determines a good sheet of plastic. There can be a surprising amount of variation in
each production run. Sometimes a manufacturer changes resins; this happens a lot when gas prices are high. Obviously, there has been a change in supplier from your distributor. I'd recommend that you buy your plastic locally (it's heavy stuff), and get to know your commercial plastics distributors. Durr-Plex is known commercially as PETG, and a sheet of plastic is usually the size of full sheet of plywood, 4'x8'. Have it cut into 24 x 24 sheets or 16x16 sheets. Color plastic is a specialty product, as is Proflex or any of the flexible thermoformable products, purchase them from O&P distributors. Try to find the generic name of the plastics you use (Durr-Plex is a trade name, which would confuse a commercial plastics distributor). Personally, I laminate as much as I can.
To our knowledge at the moment NSP specifically have the input to define what materials go into the mix for manufacture.
These pellet mixes are a virgin raw material which has no regrinds at all in them.
This can then give the plastic the best flow characteristics while being heated. As another advantage NSP also chooses the extruder which is much slower and limits shrinkage to 2% approx by volume on Copolymer and Homopolymer, more commonly known as Polypro. Quick extrusion, not virgin material will give all sorts of problems.
Flexible materials are made to a specified pellet mix also and are press molded so shrinkage is less than 1% by volume.
Unfortunately many manufacturers use regrind material and not fully virgin mixes plus use industrial grade materials not user friendly with the O & P industry.
So I would have to say NSP which we distribute has the best quality mix and manufacture techniques, especially made for O&P.
NSP = North Sea Plastics distributed by Endolite
Go with OPE or Friddle's
You might want to try Port Plastic ask for Frank
As for the most pure Plastics out- I don't know but I would recommend O&P Enterprise 800-666-0356, I've used them for many yrs. and the quality is great- they have a knowledgably staff and they stand behind there plastics. they sell all virgin plastics -
====================================================
We have been using Polypropolene from North Seas plastics for the last 4-5 years. Their prices are a bit more, but we feel it is worth it. No problems so far
This is Stuart at DAW Industries, we are the manufacturer that produces custom plastics for O&P, the real difference is that manufacturers are using a much higher percentage of what are called fillers in there plastic. Every molecule of filler means one molecule less of plastic, making the plastics weaker whiter and increasing flexibility. We carry a full line of polypro and polyethylene plastics. If I can be of further help, please contact me at 877-242-2423.
Hello Nathan; I have been using Guard Industry
Plastics for about seven years without one bad sheet.
The quality is consistant and the service is
outstanding. The phone number is: 1-800-535-3508
Hello Nathan,
I certainly am not an expert on the manufacture of plastics, but after 14 years of selling it to this field, I think I will be pretty accurate in my facts.
The fact that the material is not clearing 100% & that it's a bit more flexible probably does not have anything to do with impurities. The formula has probably just been altered slightly. You should let your supplier know this is a problem (if it is) so that maybe they can address the issue with their provider.
There are a lot of variables in the manufacture of plastics. For example, over the years I've had people comment on the color of their plastics - sometimes a bit of a blue hue or a more yellow hue or just a really white coloration. This is not anything other than the resin used to make the plastic & can vary from run to run. It cannot be controlled by the manufacturer. And, it does not affect the quality of the material.
As far as some distributor claiming they only had their plastic manufactured for O&P and was very pure - I would venture to say that all the distributors that have been around in this industry for anytime at all know the importance of quality plastic for O&P. Therefore, they are going to require that their manufacturers provide that quality to them. Our company has been servicing this industry for over 30 years & understands that. But that's no guarantee there will NEVER be any issues because when you're dealing with people, things do happen.
One issue in this industry is how over the last 8-10 years many distributors have jumped into this market without much knowledge of the O&P industry & the quality requirements. They have traditionally sold industrial grade plastic to all their other customers & try to pawn off that same quality to O&P, which needless to say doesn't fly if quality is a concern.
I hope this helps & that you get your situation resolved to your satisfaction.
Karran Martin
Account Manager
O&P Enterprises, Inc.
Try North Sea Plastics. In Canada, they are distributed by Orto Ped. I believe it comes from Scotland
Guard Industries
had the same reaction earlier in the year and had ordered plastic from
two sources-Cascade and Professional plastics in Kent, WA. They both
have the same supplier and although the plastic worked it never turned
clear in the oven.
They claim it was a change in the formula and have rectified the
problem. I am not sure where you are located but I would assume the O &
P Enterprises would be able to help-@ 800 666-0356 ask for Karen.
My name is Lisa Alston with Allied Plastic Supply in Dallas TX. We have O & P grade plastic with great pricing due to our large quantity buying power. Our plastic is all virgin material with no regrind. We keep the same manufacturers so it is very easy for us to monitor our plastic's quality. I would be glad to send you our pricing with references. I would also love to send you a sample to test so you can see the quality.
I hope to hear from you soon,
Lisa Alston
Allied Plastic Supply
866-472-1107
have had no problems with simona plastics. I know that north sea
plastics is very high quality as well...very pricey too!
TUPPERWARE!
____________________________________________________________________________________
Be a better friend, newshound, and
know-it-all with Yahoo! Mobile. Try it now. http://mobile.yahoo.com/;_ylt=Ahu06i62sR8HDtDypao8Wcj9tAcJ
Hi,
Our regular plastic distributors have apparently switched their manufacturers,
or at least are getting lower quality plastics now. What we are seeing is
polypro that has a milky look to it, and in some cases never goes clear during
heating. This alone is not an issue, but the plastics are more flexible than in
the past. I think that they have more impurities in the plastic, that is making
it more flexible.
My question is: who has the most pure platics? I remember one of the
distributors claiming that they only had their plastic manufactured for O and P,
and was very pure.
Thanks,
Nathan Keepers, CPO
We had the same experience and were told it was the same product. So we switched to APS Allied plastics out of Texas. If you purchase more than $499 of plastic, shipping is free. Now, they have both types of plastics; you just need to let them know you need O&P grade and they will get the good old original polypro for you. Their number is 888-838-2287.
I use allied plastics in dallas texas.
Who are you using now? We use O&P Enterprises and don't have any issues at present
I am producer of all kinds of thermoplastic sheet for Orthosis . But I am student in Uk (PhD0 and my company is in Iran.
I get my plastic from a private company in Seattle called Port Plastic and we've had no problems and have not seen any changes except higher prices.
If you need their number, let me know. They ship by truck.
We use American Plastics and we have had no problems with there products.
Give Allied Plastics in Dallas a call, ask for Lisa Alston, I'm sure you
will be pleased with the quality of thier plastics
I am not sure who has pure plastic. But may I ask who was your supplier? Because today I actually had a problem at work with our 1 mm white polyethylene that we purchased from Pel Supply. I had a new piece and it shrivels up like a piece of bacon and never turned clear. Then,I found a square piece of our old 1 mm polyethylene and it heated perfect and even turned clear.
I don't know if it helps but we recently started getting plastic from American Plastics and its really good quality. If you use Otto Bocks Thermolyn Stief, call American Plastics they have the same exact plastic for less.
i have not used them, but guard industries in st louis claims they have very good plastic. i would like to try them but they are a bit more expensive than cope plastic and my manager won't let me switch. give them a try.
Hi Nathan,
Regarding pure plastic:
The definition of pure polypropylene as your are seeking is a very
subjective. Since we do not have a defined standard for orthopedic grade
polypropylene, there are numerous definitions fitting various end use
capabilities that are marketed as such.
Some of the orthopedic grade materials that is sold in O&P is classified
as FDA material. This material is usually a FDA food grade meaning that the
material can have contact with consumable food, and usually is used in
packaging for food. The thinking is if the material is good enough to eat
food from or for the storage and transportation of food, then it must be
good enough to be in contact with the human body.
The U.S. Food & Drug Administration (FDA) requires that plastics used in
food packaging be of greater purity than plastics used for non-food
packaging.
Food grade plastic does not contain dyes or recycled plastic deemed harmful
to humans. However, this does not mean that food grade plastic cannot
contain recycled plastic.( <URL Redacted>)
Of course if you think FDA food grade PP is pure take a look at the FDA
regulation:
<URL Redacted>
Westlake Plastics ( <URL Redacted>) does make a
medical grade polypropylene which they call Propylux HS2. It is used for
medical instrument trays that require sterilization. I have not seen this
extruded material used in O&P and quite frankly, it probably would be to
expensive for our needs and not be of the type of resin formula that would
be compatible with actual skin contact. Westlake also makes implantable
thermoplastic polymers, but that is an obvious unrelated application and
topic.
There are companies that advertise an orthopedic PP. Proteus® O&P Grade
Sheet is an example. Usually these are virgin grade materials, i.e., they
only contain virgin PP pellets, as they come from the resin manufacturer who
conducts the large scale polymerization of propylene gas into a solid, and
the various additive to make the finished resin compatible with the end use.
In the case of O&P, the resin first must be compatible with the extrusion
process and have a melt index to match the process for thermoforming. Just
remember, that there is no set standard for orthopedic grade so these
companies set their own standard for the product they are selling and thus
calling it orthopedic grade.
Although it is possible to formulate a pure polypropylene, it is usually
necessary to mix additives in with the basic resin. Additives ease the use
of PP for extrusion and UV additives are added for protection against
exposure to sunlight. If you took the time to read or scan the FDA link of
food grade, you saw that there are a multitude of additives that give PP
various characteristics. In essence a pure PP is hard to find.
The best means to assure a consistent supply of PP sheetstock to your lab is
to communicate with your sheet distributor to confirm that they always buy
the specific polymer type from an extruder who in turn is always using the
same resin from the PP producer. It is a three step process: distributor -
extruder - resin manufacturer. Your simple visual inspection of your
sheetstock indicated that there was some change in the material. Since the
material did not turn clear at melt temperature would indicate that there we
some additives in the PP resin, or it was a PP mixture that contained
regrind or another resin type entirely. PP will turn clear at melt
temperature as the molecular structure changes from a semi-crystalline
structure to an amorphous structure which allows visible light rays to
actual pass through the structure instead of refracting as it the case with
room temperature PP and it normal opaque appearance.
Polypropylene is a difficult material for use in our vacuum thermoforming
process due to its semi-crystalline chemical structure. Inconsistency in the
procurement of your raw sheetstock certainly does not help with even simple
lab process controls.
We have had the same experience with the aded problrm of our braces were cracking as we began to cut them off the mold. there seemed to be tension maybe because of inadequate stress relief.
I used to be in the plastics business. The plastic you describe is a Poly-Hi solidur product. The milky white appearance you are describing is an optical whitening additive (think bright white). It's not particularly bad or good, just different. I sold lots of Poly-Hi material into O&P accounts ten years ago. There really isn't an O&P plastic, although some manufacturers' products are marketed as such. The O&P market is too tiny to sustain specific production (despite what people may say). Pure or virgin plastic is a myth, every manufacturer slips a bit of regrind into their products (I've been to the plants), some more than others. The key is start tracking your distributor's brand of plastic. Different manufacturers use different resins, and some are more suited to O&P. It is both the resin used and the quality of the manufacturing process that determines a good sheet of plastic. There can be a surprising amount of variation in
each production run. Sometimes a manufacturer changes resins; this happens a lot when gas prices are high. Obviously, there has been a change in supplier from your distributor. I'd recommend that you buy your plastic locally (it's heavy stuff), and get to know your commercial plastics distributors. Durr-Plex is known commercially as PETG, and a sheet of plastic is usually the size of full sheet of plywood, 4'x8'. Have it cut into 24 x 24 sheets or 16x16 sheets. Color plastic is a specialty product, as is Proflex or any of the flexible thermoformable products, purchase them from O&P distributors. Try to find the generic name of the plastics you use (Durr-Plex is a trade name, which would confuse a commercial plastics distributor). Personally, I laminate as much as I can.
To our knowledge at the moment NSP specifically have the input to define what materials go into the mix for manufacture.
These pellet mixes are a virgin raw material which has no regrinds at all in them.
This can then give the plastic the best flow characteristics while being heated. As another advantage NSP also chooses the extruder which is much slower and limits shrinkage to 2% approx by volume on Copolymer and Homopolymer, more commonly known as Polypro. Quick extrusion, not virgin material will give all sorts of problems.
Flexible materials are made to a specified pellet mix also and are press molded so shrinkage is less than 1% by volume.
Unfortunately many manufacturers use regrind material and not fully virgin mixes plus use industrial grade materials not user friendly with the O & P industry.
So I would have to say NSP which we distribute has the best quality mix and manufacture techniques, especially made for O&P.
NSP = North Sea Plastics distributed by Endolite
Go with OPE or Friddle's
You might want to try Port Plastic ask for Frank
As for the most pure Plastics out- I don't know but I would recommend O&P Enterprise 800-666-0356, I've used them for many yrs. and the quality is great- they have a knowledgably staff and they stand behind there plastics. they sell all virgin plastics -
====================================================
We have been using Polypropolene from North Seas plastics for the last 4-5 years. Their prices are a bit more, but we feel it is worth it. No problems so far
This is Stuart at DAW Industries, we are the manufacturer that produces custom plastics for O&P, the real difference is that manufacturers are using a much higher percentage of what are called fillers in there plastic. Every molecule of filler means one molecule less of plastic, making the plastics weaker whiter and increasing flexibility. We carry a full line of polypro and polyethylene plastics. If I can be of further help, please contact me at 877-242-2423.
Hello Nathan; I have been using Guard Industry
Plastics for about seven years without one bad sheet.
The quality is consistant and the service is
outstanding. The phone number is: 1-800-535-3508
Hello Nathan,
I certainly am not an expert on the manufacture of plastics, but after 14 years of selling it to this field, I think I will be pretty accurate in my facts.
The fact that the material is not clearing 100% & that it's a bit more flexible probably does not have anything to do with impurities. The formula has probably just been altered slightly. You should let your supplier know this is a problem (if it is) so that maybe they can address the issue with their provider.
There are a lot of variables in the manufacture of plastics. For example, over the years I've had people comment on the color of their plastics - sometimes a bit of a blue hue or a more yellow hue or just a really white coloration. This is not anything other than the resin used to make the plastic & can vary from run to run. It cannot be controlled by the manufacturer. And, it does not affect the quality of the material.
As far as some distributor claiming they only had their plastic manufactured for O&P and was very pure - I would venture to say that all the distributors that have been around in this industry for anytime at all know the importance of quality plastic for O&P. Therefore, they are going to require that their manufacturers provide that quality to them. Our company has been servicing this industry for over 30 years & understands that. But that's no guarantee there will NEVER be any issues because when you're dealing with people, things do happen.
One issue in this industry is how over the last 8-10 years many distributors have jumped into this market without much knowledge of the O&P industry & the quality requirements. They have traditionally sold industrial grade plastic to all their other customers & try to pawn off that same quality to O&P, which needless to say doesn't fly if quality is a concern.
I hope this helps & that you get your situation resolved to your satisfaction.
Karran Martin
Account Manager
O&P Enterprises, Inc.
Try North Sea Plastics. In Canada, they are distributed by Orto Ped. I believe it comes from Scotland
Guard Industries
had the same reaction earlier in the year and had ordered plastic from
two sources-Cascade and Professional plastics in Kent, WA. They both
have the same supplier and although the plastic worked it never turned
clear in the oven.
They claim it was a change in the formula and have rectified the
problem. I am not sure where you are located but I would assume the O &
P Enterprises would be able to help-@ 800 666-0356 ask for Karen.
My name is Lisa Alston with Allied Plastic Supply in Dallas TX. We have O & P grade plastic with great pricing due to our large quantity buying power. Our plastic is all virgin material with no regrind. We keep the same manufacturers so it is very easy for us to monitor our plastic's quality. I would be glad to send you our pricing with references. I would also love to send you a sample to test so you can see the quality.
I hope to hear from you soon,
Lisa Alston
Allied Plastic Supply
866-472-1107
have had no problems with simona plastics. I know that north sea
plastics is very high quality as well...very pricey too!
TUPPERWARE!
____________________________________________________________________________________
Be a better friend, newshound, and
know-it-all with Yahoo! Mobile. Try it now. http://mobile.yahoo.com/;_ylt=Ahu06i62sR8HDtDypao8Wcj9tAcJ
Citation
Barnhart Prosthetics, “plastic responses,” Digital Resource Foundation for Orthotics and Prosthetics, accessed November 1, 2024, https://library.drfop.org/items/show/229316.
