Tide Pods - why don't they spontaneously disintegrate?

Factual Questions
1

I assume people know the product I am talking about, but just in case, see Tide Pods.

I use Tide Pods for my laundry and they are quite convenient (no kids in the vicinity that might be at risk, so poisoning is not a concern). What I can not figure out is how they hold together before being tossed in the wash?? They definitely contain a thick liquid, not a powder. The instructions warn that they should be kept dry and they disintegrate fairly rapidly in the wash (I use front load washers so I can sometimes see them tossed around).

Why doesn’t the liquid inside the pouches break them down before they are used?

2

WAG: The plastic dissolves in water, and the contents of the pod are not water-based.

3

You’re probably right, but it then makes me wonder what the stuff is?! It has to be able to dissolve in water after the pod breaks apart and not leave marks on the clothes.

4

The pods are a polyvinyl alcohol film. The product inside contains less water than pourable deterent.

5

Cool! Thanks! I did attempt to google an answer to my question, but your google-fu is obviously better than my google-fu.

6

I assumed you were talking about Tetrapods, invented in France, but popular in Japan ( along about 15,000 km of beautiful concrete coast ).

7

But even 10% is still genuine water. I imagine that the pods ARE dissolving albeit very slowly. If I am correct, then how long would that take?

8

When I worked as a truck driver I used to do a collection from a firm that manufactured something similar. Naturally there were “KEEP DRY” sign on the cartons. A careless fork lift truck driver left 12 pallets of them out in the rain - large insurance claim and a new vacancy for a FLT driver.

9

Takes me several months to get through a container of 72 of them, and I haven’t noticed any issues with the last few in a container. So, it has to be d–n slow

10

Heat’s probably got something to do with it. Try dropping one in a pan of room-temp water and another in a pan of almost boiling water. Good bet one will fall apart in seconds, the other in minutes.

11

At concentrations as low as 10%, most of that water is going to be tightly bound to the detergent. After all, detergent molecules work by having a hydrophilic end to bind water, and a hydrophobic end to bind greasy things. At some sufficiently low concentration, the water in the detergent solution will reach a steady state where there will never be enough available to associate with and dissolve the PVA film.

12

A lot of people wash clothes in cold water which is usually well below room temp. And in many areas of the country the cold water temp in the winter is quite chilly.

13

Good point. :smack:

I use similar pod-based packaging for my dishwasher detergent but not for my laundry detergent. So I’d unconsciously substituted one for the other while thinking about the OP. Dishwashers wash using very hot water. Clothes washers not so much. Thanks. :smack:

14

I used one of those PODs (not Tide, a store brand) in cold water once. It didn’t dissolve fully, leaving a plastic residue on my clothes. Re-rinsing in warm water got rid of it. So temperature still has an effect.

15

Thank you. Chemistry was never my strong subject. I always forget that a solution is not merely a very heterogeneous suspension, but that there are interactions on the molecular level.

16

NOT denying that it happened to you, but I am surprised. Maybe it relates to front-load vs top-load washers? (I use front-load)

17

Isn’t it the same as the pods (although I don’t think they call them pods) that are used in the dishwasher? I just looked and what I have now is a powder inside the plastic, but I’m sure I’ve bought dishwasher detergent pods with a liquid like substance inside of the plastic.

18

It probably goes without saying, but don’t test them by dissolving one on your tongue. They’re apparently quite deadly.

19

And tangy.