Complex plastic coke bottles -- what happened?

June 5, 2008 1:08 PM

Those big plastic soft drink bottles used to be a two-part construction, with an opaque sleeve or cup around the lower half. Why were bottles made that why, and why did they stop?

I seem to recall some mid-80s controversery involving recycling, but the container histories I've found online are skipping this detail.

posted by Rash to Grab Bag (14 answers total)

Yeah I remember those bases, not covering the whole lower half just 3-4 inches. They made the bottles more stable, but really were an enormous waste of plastic.
posted by Science! at 1:18 PM on June 5, 2008

I remember taking them off and using them for growing plants for various sunday scool / day camp science projects. They had little holes in the bottom for some reason. When did they disappear? Late 80's?
posted by thewalrusispaul at 1:31 PM on June 5, 2008

I can tell you what I remember (very hazily for sure) from going on a 6th grade field trip to the Eastman Kodak plant in Kingsport, TN in the mid 80's. We toured the plastics lab, and one of the things they made there were those two-liter bottles.

The bottle started out looking like a fat test tube of thick plastic (very phallic), but with the normal screw-threaded neck of a two liter. The tube itself was no wide than the neck. Next, the neck was inserted on a metal spout that blew super-heated air that simultaneously softened the plastic and blew up the plastic form like a balloon. Then you had two liter bottle, but with a rounded bottom. It was inserted into the hard plastic sleeve so that it would have a flat bottom for sitting.

Now, if they told us why it was done this way, I can't recall. I only remember being mildly impressed with the process.
posted by kimdog at 1:31 PM on June 5, 2008 [1 favorite]

It appears that early one piece PET bottles were prone to stress cracking. A hemispherical base was structurally stronger, but needed the base cup to stand up. As a bonus, the base cup protected the bottle from "filling-line lubricants". As PET bottle design and handling improved, the base cup was no longer necessary.
posted by zamboni at 1:46 PM on June 5, 2008

There are only two reasons to change mass-consumed packaging: strength and cost.

The two-part bottle was the stronger bottle, but as soon as manufacturing improved to the point where the one-piece was practical, they changed.

Imagine how much money you save if you cut even a fraction of a cent off the cost of each of a billion plastic bottles. (You save plastic too.)
posted by crickets at 1:52 PM on June 5, 2008

I want to say I remember these, and I'm only 17 years old. Possible these were around in the early 90's in some form or fashion?
posted by Precision at 1:57 PM on June 5, 2008

I definitely remember these; I'm pretty sure (as others have said) that the opaque plastic bases were to keep the bottles standing upright. With advances in plastics technology (PLASTICS, MY BOY! PLASTICS!) the "feet" are now an integral molded part of the bottle so that separate "stand" is no longer necessary.
posted by mrbill at 2:04 PM on June 5, 2008

Precision, they were. It was the mid 90s before the old bottles were phased out. They started in the early 90s with plastic 16oz bottles (now 20oz bottles), and only later moved on to one piece 2 liters. For the longest time I thought they looked strange. Now I'd probably think a two piece bottle looked strange.
posted by wierdo at 2:08 PM on June 5, 2008

I specifically remember a commercial in the 80's that touted those bases as providing more strength in case the bottle was dropped. There was a scene that showed a mom putting stuff on a kitchen table and a slo-mo shot of her dropping the bottle and it it hitting the floor and doing a slight bounce rather than splitting open. I seem to remember my older brother saying that they added those bases to strengthen the bottle. I always assumed they came up with some sort of higher quality compound (you know, with science!) that allowed them to do a one-piece bottle with the same strength.

I wonder if there's some plastics trade group that could give you the information?
posted by mattholomew at 2:22 PM on June 5, 2008

I don't know what they were for, but I know they were around long enough to be included in the popular 80s book of humorous neologisms, Sniglets:

Bevamirage: The 4-inch-tall piece of black plastic on the bottom of a 2-liter soda bottle that makes you think there is still some cola in it, even though it's empty.

posted by BitterOldPunk at 2:32 PM on June 5, 2008 [1 favorite]

It was widely rumored that these usually opaque bottoms in a color vaguely matching the drink (green for 7-Up, black for Coke or Pepsi) were supposed to disguise the actual terminus of the bottle. The bottle looked larger, so customers thought they were buying more.
posted by bad grammar at 4:49 PM on June 5, 2008

Response by poster: A hemispherical base was structurally stronger, but needed the base cup to stand up.

Yes! Now I remember taking one apart, and discovering the rounded bottom. But eventually, a method was developed for injection-molding today's default "petaloid" shape (thanks for the term, Comrade_robot) making the two-piece construction obsolete.

Now I'd probably think a two piece bottle looked strange.

I've forgotten the details of their appearance. Anyone got a pointer to a picture?
posted by Rash at 5:58 PM on June 5, 2008

See above - the picture's down the bottom.
posted by zamboni at 6:06 PM on June 5, 2008

They make the new bottles so thin now that if you're squeezing a bit when you open the lid, you force liquid out the top. The Nestle iced tea (or is it Lipton) bottles are especially bad for this.
posted by jeffmik at 8:18 PM on June 5, 2008