Material Constituents of Baby Diapers

<......weight percent of disposable baby diapers......recycle them......>

It would depend largely upon the quantity of moisture and nature and level of settleable solids they contain at the point of recycling. There must be people in this world that measure these parameters?

It would depend largely upon the quantity of moisture and nature and level of settleable solids they contain at the point of recycling.

Not only that, but in this country the manufacturers of diapers kept information like that under lock and key.

Its because that it's not only very competitive, its very big business $$$$$.

For my preliminary process design I proposed re-grinding the diapers, put the particles into a water slurry, and then sending the particles through a perforated sludge dryer to continuously separate the plastic from any "residual baby waste".

This is my post by the way. I neglected to sign in before I asked, whoops.

What are the chances of the materials being flame retardant?

Ben Bonsens,

its how you separate the absorbant material from the plastic. identifify these materials is the difficult part as my earlier post stated. Once id'ed then one can attempt to develop a process to separate the materials.

Are you the guest that posted this originally?

phoenix911

Yep its my post.

As to separating the absorbant material from the rest of the material, how about gravity separation after the sludge dryer? Cheap, easy to predict, and well understood.

to remove the influent in the sludge, that can be run through a rotary drum strainer, (typical process in the sanitation industry).

Do not know if any of the aborbant would also break down.

But before one can talk about separating or processing this, one needs to find a market.

Which brings us back to your first question, material types.

phoenix911

A coworker has mentioned that the absorbant material used to be either a hydrogel or a polyethylene foam, and the outer casing was a polypropylene. If he's right than my preliminary process can't have a water slurry prior to separation, otherwise there'll be a "colloidal mess" (sorry for the bad rheology joke there just couldn't help it).

The recycled constituents are part of a "value added" portion to an existing product line. So we've got the market, I'm just not sure about the feasability.

"A coworker has mentioned that the absorbant material used to be either a hydrogel or a polyethylene foam, and the outer casing was a polypropylene."

Asto the absorbent, I believe this is no longer the case for the bulk of the disposable diaper manufacturers, but I work in a related field so I am unable to give details about the contents.

What I will say is that hydration does not seem like it would allow for seperation of the various ground-up contents.

Assuming the same particle size (at least within a standardized mean) you can dry separate via density differences using forced air.

Some "dry cyclones" work this way for mineral separation, but it usually takes several cascaded steps to get a desired purity.

Most of the absorbant diapers and pads for adults with leaky bladders are made from polyethylene glycol [Carbowax] with 8,000 to 14,000 MW, typically with MDI. Also small, flat sponges that "pop-up" when immersed in water. And yes, the actual composition is not readily available. I suspect that you'll have more problems with the FDA or similar health concerns re microbial contamination, etc. That could be a real problem, to assure that no bacteria etc are present in your processed materials.

Thanks!

Microbial contamination can be avoided with a pastuerization step. We'll just have to incorporate a biology QC step into the process to make sure we're "clean".

You should do a search for SAP (super absorbent polymers). These are patented materials that make the new diapers so thin.

They can hold 20% up to 38% times their weight in liquid. I think this number is correct.

I have worked with some "companies" on manufacturing systems. They use high intensity, very specific band widths of UV light in thier process.

These materials may be one way only, and not recyclable. At least not able to retain all of thier original properties.

Google Patent Search says you are right as to the "one way" processing. Which is making me question the feasability even further.

Thank you for the good, hard data.

I'm glad it was helpful.

I am not an engineer in practice, I just play one at work. So any contribution that is helpful to others helps my justify my presence once in a while.

Forgive me if I'm thinking or raining on a noble parade here, but I think it's been tried here in the US serveral times, but it's not a matter of the actual recycling of the material that has stalled it, more of a regulation nightmare on the Biohazard of human waste issue that's killed the attempts. Might I suggest several thousand pounds of electrically dischargable, plasticine like material liberally distributed to your current ruling body as an easier, if messier solution to the beaurocratic injustices.

Don't listen to me, I just dispise negotiating with my employees.

The best adult diapers that are on the market is made from a company called Medline. Medline diapers are superior in terms of quality, controling leakage and just overall feel. When my mother first started using adults diapers, I tried all the other brands depends, Tranquility Products, and Tena Products all of them where not good because my mother had a heavy incontinence problem and those diapers would leak. I then bought some diapers from www.ionmeds.com/ made by Medline and they where great. And they cost me less than the other diapers. I hope whoever reads this checks out the site IONMEDS they will help