Why Are The Bottoms Of Plastic Water Bottles Concave?

- Jun 03, 2019-

Why are the bottoms of plastic water bottles concave?

I believe that many attentive readers will find in life that the bottom of the drinking water bottle we usually buy is concave, so why?

01. The bottle-making process is simple. Because of the pentagonal concave shape of the bottom of the bottle, it is easier to blow the bottle.

02. Material savings - If flat bottoms are made, the bottoms must be thicker to withstand the pressure of liquids, which leads to waste of materials. The use of concave shape, on the surface, seems to be a waste of material, but in fact, it can make the bottom thinner, but save material because the five corners share the liquid pressure equally.

03. Increase the strength of the bottom of the water bottle - pentagonal concave design, so that it can be moderately deformed to reduce the degree of damage.


These are the parts that the manufacturer will notice in the process of injection moulding. For our consumers, we may need to pay more attention to the safe use of some materials.


Choose plastic bottles with safe materials when buying plastic water bottles.