stringy character of Shampoo

I saw this in happy.com but don't know what is the stringy character of Shampoo formula. Can you help!

After a certain amount of salt has been added, the viscosity peaks and any more salt will actually reduce the viscosity rather than increase it. This type of curve is useful for adjusting the viscosity of the product. Some formulators purposely exceed the curve in order to reduce the stringy character of the formula. Stringy flow can also be corrected by adding a little polysorbate 20 or propylene glycol to the formula.

Comments

  • PerryPerry Administrator, Professional Chemist
    "Stringy flow" relates to the tendency for the stream of product to stick to the container when you are pouring it our. 

    When you pour water our of a pitcher, as soon as you lift it up and stop pouring, the stream of liquid cuts off and there is a complete separation from the stream and the container.

    When you pour a "stringy" liquid, something like honey, when you lift up the container to stop the pouring, the liquid remains attached to itself and the container. There isn't a clean break like there is with water. There is a fine strip of liquid the remains connected and this literally can look like a string. Thus the name. 

    These are two extreme examples. Depending on how it's formulated, a shampoo can be more or less stringy.  Typically, when you use a polymeric thickener like a cellulose you might get a stringy effect on pouring.
  • @Perry so this stringiness of Shampoo doesn't have an effect on hair and scalp? 

    Does increasing the salt reduce stringiness? 
    If yes, is it the more salt the less stringiness or it is something like salt curve?


  • PerryPerry Administrator, Professional Chemist
    No, stringiness doesn't have any real effect on the hair or scalp. It could affect how quickly or easily the product produces foam or maybe even rinses out. But it's mostly about how it comes out of the bottle.

    Salt may or may not impact stringiness. It depends on the formula. There is no general answer.
  • @Perry thanks a lot
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