Least plastic smell
Least plastic smell
(OP)
I am the owner of a weighted blanket business (used in treating Sensory Processing Disorders...common with Autism). I am not an engineer, so please forgive any inconsistencies in my question.
I have been using underwater processed PE pellets from a plastics recycling plant as weighting material in my blankets, but each lot of beads that I buy has a distinct odor that is often offensive to my clients...and each lot smells different from the last lot. I am wondering if I would be better off using PP? Would Virgin Plastic rather than reprocessed have less of an odor? I know that there are a gazillion combinations...I believe that most of the lots I've been buying have had the label LDPE (or something like that). Is there a different PE combination that I should ask for to achieve less of an odor?
Thank you in advance for any advice you may have to share.
Kristi
I have been using underwater processed PE pellets from a plastics recycling plant as weighting material in my blankets, but each lot of beads that I buy has a distinct odor that is often offensive to my clients...and each lot smells different from the last lot. I am wondering if I would be better off using PP? Would Virgin Plastic rather than reprocessed have less of an odor? I know that there are a gazillion combinations...I believe that most of the lots I've been buying have had the label LDPE (or something like that). Is there a different PE combination that I should ask for to achieve less of an odor?
Thank you in advance for any advice you may have to share.
Kristi






RE: Least plastic smell
Try some virgin material.
Mike Halloran
Pembroke Pines, FL, USA
RE: Least plastic smell
Kristi
RE: Least plastic smell
I don't think their natural odor is substantially different, or particularly strong. If you buy odd lots/ overruns of custom compounded stuff, well again, it could have anything in it...
Mike Halloran
Pembroke Pines, FL, USA
RE: Least plastic smell
Chris DeArmitt - PhD FRSC CChem
Plastic & Additives Webinars
Instant Downloads & Inexpensive
www.plastictraining.com
RE: Least plastic smell
Chris, thank you for name dropping some starting places for researching suppliers. I tried several different Google searches but I couldn't seem to hit on the right search terminology to turn up the type of suppliers I need. I have minimal experience in this, but I suspect that my next hurdle will be finding a supplier that will sell by the ton rather than the truckload. Any advice in this regards would be most welcome.
In 2010, I purchased some 'end of run' PP lots from a supplier that were a dream come true. But then when I went back to the same supplier for a second shipment, they sent me some kind of powdery 'bisque' pellet (rather than the PP that I'd requested). I'm sure it was probably top quality and a dream come true for someone else, but for my purposes, it was completely unusable. It was at that point that I searched and found my current supplier (underwater reprocessed beads that are unpredictable in smell).
Smiles.
Kristi (in Alabama)
RE: Least plastic smell
http:
If it's a burnt rubber or burnt plastic kind of smell - likely the reprocessor ran the batch at too high a temperature, and literally scorched the plastic. I'd send it back in that case.
RE: Least plastic smell
Thank you for that link. The smell is definitely a chemical odor...or maybe a solvent odor...I wouldn't know the difference. :( I'm sorry.
I tried rinsing the beads, rinsing them in vinegar, putting fans on them (thinking they just needed to air out), setting them out in full sun...none of these made any difference. What I DID find makes an improvement is to boil the beads in water with a tsp of Palmolive for 15 -30 minutes and then rinse them (boiling just in water does not help).
I followed up on all of the companies that Chris mentioned. They each gave me the names of other companies that might be able to help me...so, tomorrow I will contact those new companies. I'll be curious to see what the price difference is between virgin versus reprocessed.
Kristi
RE: Least plastic smell
Other grades can have any number of additives.
post consumer waste could contain anything, including some decayed food.
Regards
Pat
See FAQ731-376: Eng-Tips.com Forum Policies for tips on use of eng-tips by professional engineers &
http://eng-tips.com/market.cfm
for site rules
RE: Least plastic smell
Chris DeArmitt - PhD FRSC CChem
Plastic & Additives Webinars
Instant Downloads & Inexpensive
www.plastictraining.com
RE: Least plastic smell
Chris, I have a question that I am sure will show the full extent of my ignorance...if recycled plastic could contain food waste, then could recycled medicine bottles contain traces of the medicines they once contained? I do not know enough about the recycling process to understand why it would be a concern with food, but not with medicines. Would the medicine traces (if there are any) render the plastic no longer 'non-toxic'?
I am learning so much from y'all. I really do appreciate the time y'all are taking to educate me.
Kristi
RE: Least plastic smell
Obviously, you'll have to come up with a reasonable definition of what 'clean' means for you. We have a standard note on most of our machined parts saying "FINISHED ARTICLE SHALL BE FREE OF OILS, LUBRICANTS AND OTHER CONTAMINANTS PRIOR TO BEING PLACED IN SEALED BAG." You'll need to come up with a different or more detailed spec, especially referencing the odor aspect, but hopefully you get my point.
Sometimes you need to actually solve problems like this, other times you just need to accurately specify what you actually need.
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: Least plastic smell
Chris DeArmitt - PhD FRSC CChem
Plastic & Additives Webinars
Instant Downloads & Inexpensive
www.plastictraining.com
RE: Least plastic smell
Truer words have never been spoken. There is a learning curve in this (for me), and I know that I'll get more of what I actually want the more I learn how to accurately ask for it. :)
Thank you (everyone) for the excellent tips (and any more that you share). What I have learned so far...(correct me if I'm wrong)...
-Contaminants and additives cause odor.
-Pure Virgin PE would have no contaminants and the fewest additives resulting in virtually no odor...but probably at a premium price.
-My current bead odor (given that it is recycled plastic), probably has both internal contaminants and unknown additives as well as surface contamination. Boiling the beads in detergent/water seems to solve the odor problem (though I don't know if the internal contaminants will then result in future odor in the same beads, or once the odor is gone, it's gone).
:) If I got all of that right, then it is completely to the credit of this forum. Thank you.
Kristi
RE: Least plastic smell
Chris
Chris DeArmitt - PhD FRSC CChem
Plastic & Additives Webinars
Instant Downloads & Inexpensive
www.plastictraining.com
RE: Least plastic smell
A good test for cleanliness after washing would be to take a pound or so of the washed and dried beads, and put them into a commercial, food-grade, cooking bag (the kind they sell at grocery stores to roast turkeys in). Seal the bag, maybe double-bag it, and toss it in an oven at a low temp (maybe 200 to 250 F) for an hour or two. Remove the bag, open it and sniff. Any volatile compounds left in/on the plastic should desorb when they are warm and present an odor.
You may find that repeated rinse/wash/dry cycles do a better job of extracting odors, you might also find that a wash, rinse, vacuum dry, and re-wash gives very good results. Vacuum drying tends to help force contaminants out of crevices as the water vaporizes, leaving the contaminant on surfaces more readily exposed to the detergent on the next wash cycle.
RE: Least plastic smell
I do not have access to freeze drying. Would putting the beads in the regular deep freeze for 24 hours after boiling them do anything for it?
Thank you for the awesome tip. I will continue researching the costs and availability of virgin PE, but in the meantime, I have over 1000 pounds of these reprocessed beads and orders to fill while I'm looking for a new source. So, your advice is most appreciated.
Kristi
RE: Least plastic smell
Kristi
RE: Least plastic smell
We learned the technique in trying to decontaminate toxic rocket fuels (hydrazines) from complex parts/passages (think hydraulic valves). We could wash and wash, but the darn stuff would ooze out of crevices again, if we waited long enough or raised the temperature of the parts. But adding even one dry and re-wash/redry cycle gave an order of magnitude reduction in residual nasty stuff, and we could see approximately that kind of reduction with each cycle (two cycles put the apparent residue below the limit that we could detect its vapor). Ought to be at least worth a try.
I do like Kenat's idea too - just add a drawing note "no objectionable odor to be detectable", maybe add "when pellets are heated to 150 F" or some such.
Good luck!
RE: Least plastic smell
RE: Least plastic smell
Compositepro, in your experience, once I steam strip the beads to the point of being relatively odorless, should I expect the odor to stay away, or is that just a temporary fix?
Kristi
RE: Least plastic smell
Vacuum certainly accelerates the removal of volatiles greatly, and heating under vacuum greatly reduces the oxidation of the polymer due to heat aging.
If odour causing substances are distributed through the matrix of the granule, they will be hard to remove as diffusion to the surface is often slow.
Buy new virgin appropriate grade of material and sleep at night.
I know most reputable suppliers make non or low tainting grades for use in things like cookware and electric kettles.
Regards
Pat
See FAQ731-376: Eng-Tips.com Forum Policies for tips on use of eng-tips by professional engineers &
http://eng-tips.com/market.cfm
for site rules
RE: Least plastic smell
Good advice. I'm working toward that for sure. I got an email late this afternoon from the recycling plant that has been supplying me this past year, and they have offered to take back all of my current beads in exchange for new beads that are more acceptable for my purposes. I noticed on their website that they sometimes deal in virgin PE, so I'll see if they have any currently available that I could credit my current beads toward an upgrade purchase.
Also, one of the sources that Chris mentioned has connected me with a supplier that might be able to source me with virgin PE by the ton rather than by the truckload. (Thank you again, Chris).
Smiles.
Kristi
RE: Least plastic smell
Chris DeArmitt - PhD FRSC CChem
Plastic & Additives Webinars
Instant Downloads & Inexpensive
www.plastictraining.com
RE: Least plastic smell
RE: Least plastic smell
What's interesting is that autistic's are sensing this odour and reacting negatively to it.
You describe washing and drying the blankets. Forced air convection dryers get quite hot and can affect some polymers. Also, if they are gas fired dryers and don't have perfect combustion could objectionable aromatics be introduced this way? Also, to really harp on this, forced air convection tumble drying creates both static charge and carbon monoxide. Could either be inducing this negative sensing reaction?
Pardon me if I'm second guessing you, but could other synthetic fibers in the blanket fabrics' construction be another target?
RE: Least plastic smell
I'm pretty sure it is the plastic pellets themselves that had the odor because I could smell the chemical smell each time I used them. Update: The recycling plant from which I bought the smelly pellets invited me to bring them back and they gave me an even trade on virgin beads. While there, I also picked up a second pallet of virgin PE pellets. I absolutely LOVE my new pellets. They have virtually no odor and therefore require no preparation before using them in the blankets. Woohoo! I will use virgin beads from now on.
Thank you again to everyone for all the fantastic advice. I learned a lot from this board.
Kristi