Why are plastic bottles for detergent like Tide so much heavier than the bottles

[snagglepuss]

for bleach? This makes no sense.

[4Q2u2]

1. Specific Gravity

and other Chemical properties determine the type of container.

[stopbush]

2. Probably a marketing decision.

The detergent "works hard to lift the toughest stains." Can't have that sitting in a thin-sided plastic bottle.

Bleach "whitens your load and makes everything clean and bright." Can't have that sitting in a thick-sided plastic bottle.

Or maybe they do a drop test to see what thickness is needed to keep the contents from exploding when the bottle is dropped accidentally.

[Kelvin Mace]

6. Nah,

the are not going to spend +x% more for the bottle, plus pay for the added weight when shipping just for a marketing ploy.

Your last statement is the correct one.

[snagglepuss]

8. So a gallon of toxic bleach is not going to burst when dropped but detergent will?

[Kelvin Mace]

10. Our question here is the bursting point of the container relative

to the liquid contained. The greater the density, the more robust the container will need to be.

The gallon of bleach (128 fluid ozs) I happen to have in my cleaning closet weighs about 8.25 lbs (on my bathroom spring scale). The 150 oz (1.17 gallons) bottle of tide in the laundry room weighs in at about 10.5lbs.

Bleach = .06 lbs per oz.
Detergent = .07 lbs per oz.

So, detergent is a hair under 17% denser than bleach. Thus, you need a heavier container to prevent it from bursting when dropped.

The issue of toxicity is not relevant to the bursting strength of the container, unless the liquid was also corrosive to the container.

[snagglepuss]

11. Thanks for your detailed replies. This has always irked me but now I know.

I thought reducing the thickness of the bottles would be better for the environment but that is a no go. I have to wonder how much plastic has been put into the environment since liquid detergent has become the norm.

[Kelvin Mace]

12. Hey, you made me do some math

and a quick science experiment. I need to do that more often.

If memory serves I read an article in Consumer Reports some years back discussing powder versus liquid. Powder was cheaper, but contained more chemicals than liquid and could be a problem with septic tanks. Liquids were great for treating stains before you washed your clothes, but was more expensive. Powder came in boxes, thus were better for the environment and less energy to make than a plastic bottle, but there was the "more chemicals" problem.

So it seems "a wash".

[stopbush]

14. I have a question about the environment and landfills.

Does paper or plastic make a difference these days? Aren't most landfills today lined with a poly-carb liner that keeps toxins from leeching into the surrounding soil? If so, then what does it matter if the trash is paper or plastic? - neither is going to decompose all that quickly in such a landfill, and neither is going to be more likely to leech.

On another subject - paper or plastic grocery bags. I use recyclable bags, but isn't it true that pound for pound, plastic bags create less waste than paper bags? I read that it would take 7 truckloads of paper bags to equal the same number of bags that you'd get in one truckload of plastic bags.

Doesn't the amount of paper trash in landfills far outweigh the amount of plastic?

[Kelvin Mace]

15. A reusable bag trumps both

but from my own reading plastic is the better choice. Plastic has a better tensile strength, which means you can make if VERY thin and it will still hold your groceries. Paper on the other hand doesn't do well when the thickness goes below a certain point. Also, it requires a more energy to create a paper bag than a plastic and due to the thickness issue, is bulkier.

Both can be recycled.

[stopbush]

16. Thanks for the reply. I use reusable bags, but if I need extra bags I opt for plastic.

Good to know I was on the right track.

[Faux pas]

3. That's a great question

and I don't know the answer. I don't use either I use Green Laundry wash balls.
http://www.moneycrashers.com/green-wash-ball-dryer-balls-review/

[The Velveteen Ocelot]

4. Because laundry detergent is heavier than bleach.

You need a thicker, more robust bottle to prevent ruptures and spills if the bottle is dropped or banged around during shipping. A manufacturer isn't going to spend more than it has to on containers, so the bottles for both bleach and detergent are as thick as they have to be, but no thicker.

[Kelvin Mace]

5. The detergent is denser

and weighs more. A lighter container like a bleach bottle would be more prone to rupture.

[DetlefK]

7. Maybe because detergents can dissolve plastic?

Plastic-bottles aren't flat, but have pores and the content seeps into them. That's why you shouldn't reuse plastic-bottles which stored something inedible to store edible stuff.

Detergent-molecules consist chemically of a water-soluble part (connects to water) and an oil-soluble-part (connects to dirt). Plastics are basically oil and over the years, the detergent could soften up the plastic and eventually dissolve it.

Bleach does not work by helping to dissolve dirt in a liquid, it uses its electrically charged ions to destroy dirt, to cut it chemically into tiny pieces that then dissolve into the liquid by themselves. Plastic is similar to unsaturated carbohydrates, its molecules don't have weak spots where the bleach could attack with a chemical reaction. Therefore bleach can't dissolve plastic that easily and only needs a bottle with thinner walls.



Wild guess, but I assume that's the explanation.

[snagglepuss]

9. Thanks for such an informative answer. Live and learn.

[Kelvin Mace]

13. No, because if that were the case

the detergent would eventually dissolve the plastic, no matter how thick. I have cleaned out a household of two in my day that had liquid detergent in a bottle for 20+ years (forgotten in a shed/basement/cabinet) and while the detergent had separated, the container was fine.

As I noted above, it is simply a matter of detergent being denser than bleach, therefore you have to have a thicker bottle to protect against bursting. Again if memory serves, I read an article back in the day that talked about how containers for consumer products are tested and the drop distance was 3 feet, which would be about the average you would expect a container to fall if dropped by your average 5 foot 7 inch human.