Home Cosmetic Science Talk Formulating What things prevent pearlization of EGDS in shampoo?

  • What things prevent pearlization of EGDS in shampoo?

    Posted by RawMaterialGirl on January 20, 2016 at 10:08 pm

    Hi,

    I’ve noticed that in certain shampoos, EGDS crystallizes (pearlizes) quickly, but in others, it either never pearlizes fully (takes a while) or at all. I have a batch of shampoo that has pearlized consistently every single time within 24 hours… and how I have a third batch that is not pearlizing at all. The viscosity is a fifth of what it should be, and I think that is due to EGDS not restructuring. 
    Has anyone seen this? Thoughts? Thank you!
    johnb replied 7 years, 11 months ago 8 Members · 15 Replies
  • 15 Replies
  • OldPerry

    Member
    January 21, 2016 at 2:21 pm

    I saw this in some of the shampoos I worked on. It was usually the result of the salt level in the formula.  Often, surfactants are supplied with a slightly different level of ionic activity so sometimes you need to add more salt and sometimes you need less.

    The level of salt can affect the solubility of the EGDS.
    I would suggest you try a salt curve analysis on your formula to get the right level.
  • DavidW

    Member
    January 23, 2016 at 12:13 am

    IS this batch the same formulas as the others?  Often you won’t see any pearl until you thicken it up some more.

    @Perry and others.  I have see different brands of salt give WAY different thickening results so either use the same each time or be careful trying to add the same amount as your previous batch when adjusting viscosity 

  • belassi

    Member
    January 23, 2016 at 12:37 am

    I have problems sourcing salt without additives. Using table salt is not a great idea, I think.

  • OldPerry

    Member
    January 24, 2016 at 2:41 pm

    I agree. You should use the same source for salt.

  • nomi

    Member
    December 11, 2016 at 12:46 pm

    Hi,  do we add egds in soap bar? should it saponify with naoh or may use without adding lye?

  • johnb

    Member
    December 11, 2016 at 12:54 pm

    The pearl effect of EGMS or EGDS is lost in soap.

    The only reliable method of pearlising soap is with a suitable grade of treated mica.

  • belassi

    Member
    December 11, 2016 at 3:36 pm

    @johnb is correct but it’s even worse than that. By ‘suitable grade’ what he means is, that in general, many micas discolor in the high pH of soap.

  • Microformulation

    Member
    December 11, 2016 at 10:17 pm

    Relevant Article on Prospector.

  • ashish

    Member
    December 12, 2016 at 8:00 am

    Actually, I
    also faced same problem but it is totally depend on process of usage of EGDS in
    batch. When I tried to heat EGDS with 30% of SLES of the total qty. of SLES in
    batch, it imparted more pearliness than regular one. 

  • nomi

    Member
    December 20, 2016 at 7:25 pm

    are there other ingredients to produce shine and luster?

  • johnb

    Member
    December 21, 2016 at 1:47 pm

    “are there other ingredients to produce shine and luster?”
    Depends on the product. Under certain conditions some quats (particularly stearyalkonium) will give a pearl effect. Stearic acid can give a very intense pearly sheen under the right conditions/in the right formulation. Guanine crystals obtained from fish scales used to provide a pearl essence but this is no longer available - it was very expensive. For special uses powdered metal flakes (aluminium, copper, copper bronze) give a pearly sheen but these are all but impossible to incorporate into cosmetic products.

  • OldPerry

    Member
    December 21, 2016 at 6:53 pm

    I have made pearly shampoo systems with Cetyl Alcohol, Stearyl Alcohol, and even Mysityl Myristate.

  • johnb

    Member
    December 22, 2016 at 3:16 pm

    Something that’s just come to mind is a memory of a batch of EGMS which refused to form a pearl. After much investigation and consultation with the suppliers it turned out that the stearic acid used for the esterification contained an appreciable amount of unsaturated acids (oleic, linoleic, linolenic, etc) due to incomplete hydrogenation of the tallow fatty acid starting material.

    I had a look at this effect and found that yes, the presence of unsaturates does affect the ability to produce a pearl effect in EGMS/detergent products.

    This was a very long time ago and I’ve forgotten most of the detail.

  • nomi

    Member
    December 31, 2016 at 10:58 pm

    EGDS, in soap bar, should dissolve in water phase ? as I read in product data sheet of  Rhodia_TDS_ALKAMULS 504_V_EN.

  • johnb

    Member
    January 1, 2017 at 7:47 am

    EGDS will not form a pearl effect in a soap bar ergo there is no point in including it.

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