Using fewer types would be a start. Why do we need milk containers made from low density polyethylene, yogurt pots from polystyrene, and soft drink bottles from polyethylene terephthalate?

That is an interesting question that both pulled out some past experience, curiosity, and sent me on a small adventure across the internet.

Milk jugs are actually HDPE (high density polyethylene). When I worked at a bottle manufacturer I remembered certain food bottles we made had a ethylene - vinyl - alcohol (EVAL EVOH) polymer layer also as a barrier layer. I will not bond with HDPE so an adhesive layer was also part of the mix on both sides. Some food bottles I produced were straight HDPE, but they were also foods that generally had long if not infinite shelf lives (I don't remember the details anymore). It seems the reason it is used for milk jugs is because milk has a fairly short shelf life. Recycled HDPE is only approved for direct contact with food an a case by case basis. We turned a lot of old milk jugs into fabric softener bottles.

Yogurt containers are actually polypropylene. Polystyrene is a foam (coffee cups). I did make a few bottles from polypropylene, but never knew what the advantage was. It seems it is a good material for resisting mold and bacteria in the plastic itself. The recycled material is approved for direct contact with food with no restrictions.

PET (polyethylene terephthalate) is kind of a super plastic from what I can tell in terms of food storage. PET is also approved for direct contact after being recycled. PET takes some specialized equipment (relative to other types) to produce the bottles along with some serious air pressure. The compressor that fed those two lines where I worked ran at 500 psi compared to the rest of the plant at 120 psi. It's also a two step process to actually form the bottles compared to all other plastic types. I don't know the details, but from what I saw the process itself is more than likely quite expensive compared to other types of plastics.

We did use some low density polyethylene in a few bottles to add a little bounce to them and allow for thinner walls. It was never used to produce an entire bottle, and only a couple bottles actually used it. It was a customer specification as far as I know.

Other than that I don't know anything else. A lot of that was what I could find online other than what I remember from making bottles.

Like everything else it probably boils down to which one is cheaper for the intended use, followed by which one will do the job better, and finally which one looks better. Some things will sell better with a more attractive container.

Plain HDPE was the simplest process and I would imagine the least expensive.

HDPE with barrier and polypropylene bottles used material dryers to both keep the material as dry as possible and helped regulate the raw material temperature which added to the cost I'm sure. Both types would beat you pretty good if the material conditions fluctuated too much. Keeping track of your levels and slow changes over time was the key.

 

Yogurt containers are actually polypropylene. Polystyrene is a foam (coffee cups). I did make a few bottles from polypropylene, but never knew what the advantage was. It seems it is a good material for resisting mold and bacteria in the plastic itself. The recycled material is approved for direct contact with food with no restrictions.

https://styrolution-eco.com/content...yrolution_Polystyrene_and_dairy_packaging.pdf
although my favourite Müller fruit corners are PET.

 

https://styrolution-eco.com/content...yrolution_Polystyrene_and_dairy_packaging.pdf
although my favourite Müller fruit corners are PET.

My apologies!! I should have paid more attention in my search on that particular type. I saw your typical egg cartons and foam clam shells and didn't go any further.

 

My apologies!! I should have paid more attention in my search on that particular type. I saw your typical egg cartons and foam clam shells and didn't go any further.

Accepted.
Whatever they are made of, whilst some plastics may be a little better than others, making them all out of the same type doesn’t sound like a problem that smart chemists can’t solve.

 

Surely, there are alternatives to plastic for food packaging, paper, cardboard, wood, lined with water resistant coatings that are biodegradable such as bees wax or cellulose. You can even wrap fast food with edible cellulose and then wrapped with waxed paper.

 

 

Beautiful craftsmanship ... I've always admired Japanese carpentry.

 

 

 

Has gentle shopping cart scuff. Clean title. Make reasonable offer.

 

 

 

 

Has gentle shopping cart scuff. Clean title. Make reasonable offer.

<1k miles on brand new crumple zones. Will not respond to lowball offers.

 

<1k miles on brand new crumple zones. Will not respond to lowball offers.

IMO that is not a safe car after those 'repairs'. Beware of the scrap title.

 

IMO that is not a safe car after those 'repairs'. Beware of the scrap title.

I tend to agree. I don't have anything specific to complain about with the repairs, it seemed like they did everything properly (except for welding without a hood) and used factory replacement parts, but there are new stresses in the unibody that the designers didn't account for. I would not put my kids in it unless there were no other options. It's probably still safer than anything I was ferried around in as a kid.

 

 

 

 

Unbelievable how a lack of money and resources brings out the best of creativity in people ...