What things prevent pearlization of EGDS in shampoo?

edited January 2016 in Formulating
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!

Comments

  • PerryPerry Administrator, Professional Chemist
    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.
  • DavidWDavidW Member, PCF student
    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 
  • BelassiBelassi Member, PCF student
    I have problems sourcing salt without additives. Using table salt is not a great idea, I think.
    Cosmetic Brand Creation. Concept to name to IMPI search to logo and brand registration. In-house graphic design inc. Pantone specs. Cosmetic label and box design & graphics.
  • PerryPerry Administrator, Professional Chemist
    I agree. You should use the same source for salt.
  • Hi,  do we add egds in soap bar? should it saponify with naoh or may use without adding lye?
  • johnbjohnb Member, Professional Chemist
    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.
  • BelassiBelassi Member, PCF student
    @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.
    Cosmetic Brand Creation. Concept to name to IMPI search to logo and brand registration. In-house graphic design inc. Pantone specs. Cosmetic label and box design & graphics.
  • MicroformulationMicroformulation Member, Professional Chemist
    Relevant Article on Prospector.
    markfuller@microformulation.com Microformulation.com Microformulation Cosmetic Consulting provides Custom Formulations for both large Commercial accounts as well as smaller entrepreneurs. We can provide Naturally compliant Formulations under the NSF, NPA, Whole Foods and USDA Organic Certifications. BS.Pharm Albany College of Pharmacy, Union University.
  • 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. 

  • are there other ingredients to produce shine and luster?

  • johnbjohnb Member, Professional Chemist
    "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.

  • PerryPerry Administrator, Professional Chemist
    I have made pearly shampoo systems with Cetyl Alcohol, Stearyl Alcohol, and even Mysityl Myristate.
  • johnbjohnb Member, Professional Chemist
    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.
  • EGDS, in soap bar, should dissolve in water phase ? as I read in product data sheet of  Rhodia_TDS_ALKAMULS 504_V_EN.
  • johnbjohnb Member, Professional Chemist
    EGDS will not form a pearl effect in a soap bar ergo there is no point in including it.
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