W/O Emulsion

A sun care Formula I prepare, every time I get something else.
Once the emulsion O / W and other times it's reverse .
The emulsifiers I use are:

Pemulen TR-1 0.1%

Stearic Acid- 1%

Span 65- 0.1%

PEG 150 Distearate- 0.1%

And I have VP/Hexadecane- 3%

How can I control it-so I got to O / W or vice versa?
What causes the inverse emulsion?

Thank you!

Chief Chemist/ R&D Manager at SASA Cosmetics

Comments

  • ashishashish Member
    First of all coming to the basics in emulsions, It is a o/w type formula which can not inverse into w/o, if so, it will form same kind of emulsion which o/w forms. Generally, w/o type of emulsions are water proof kind which require w/o type of emulsifier which having HLB value from 3-6. For HLB understanding, please refer Google. Moreover, It cannot tolerate fat as it will create spreading problem. In case of w/o, mostly emollients are used and w/o type emulsifiers itself would give thickening to product.
  • ZivBAZivBA Member

    Thank you for your explanation and google references.

    Now,

    Can you please help me with my question:

    I made this formulation 4 times, two of them the emulation came as o/w, and the other two- w/o.

    How and why?


    Chief Chemist/ R&D Manager at SASA Cosmetics
  • Chemist77Chemist77 Member, PCF student
    Wow that's some result, did you change the supplier of these materials or they were all from the same supplier, I am assuming your procedure was IDENTICAL all the 4 times.
  • ZivBAZivBA Member

    IDENTICAL all the 4 times.

    The only thing that I changed was the homogenization time, and temp of the oily phase (50c & 70c).

    After each time I'm dissolving the emulsion in water or C12-15 Alkyl benzoate, that's how I know if it's W/O or O/W. 

    That's why I cannot understand or explain why I'm getting those results.

    I'm just looking for consistency.......

    Do you have any idea?

    Chief Chemist/ R&D Manager at SASA Cosmetics
  • Bill_TogeBill_Toge Member, Professional Chemist
    what's in the rest of your formula?
    UK based formulation chemist. Strongest subjects: hair styling, hair bleaches, hair dyes (oxidative and non-oxidative) I know some stuff about: EU regulations, emulsions (O/W and W/O), toothpaste, mouthwash, shampoos, other toiletries
  • ashishashish Member
    First of all, do you want to develop o/w or w/o?. As given formula contains both which you mentioned in your comment. If you need o/w then, why are you using w/o type of emulsifiers? and vice versa. In w/o, all emulsifiers would be its type only. It may be due to Antaron i.e.VP/Hexadecane. Please share rest of the ingredients.
  • chemicalmattchemicalmatt Member, Professional Chemist
    I will second Bill Toge's question regarding your conundrum: what else is incorporated here?  It is doubtful, if not impossible, for an emulsion based on (neutralized) Pemulen to invert to w/o. There must be another factor, or your empirical observations with Finsolv TN are throwing you off (and I am a big fan of Finsolv TN as everyone knows.)  
  • ZivBAZivBA Member

    Thank you all for your time.

    chemicalmatt - Maybe you right and the test with C12-15 Alkyl Benzoate isn't suitable for this formula.

    When I put it in water it crates perfect drops inside the water that doesn't mix, and settled at the bottom of the beaker.

    Can you suggest anything else?

    Full Formula:

    Water QS

    Pemulen TR1- 0.1

    Sorbitol 70%- 3

    TEA- 0.05

    Avobenzone- 3

    Homosalate- 13

    Octyl Salicylate- 5

    Octocrylene- 2

    Oxybenzone- 4

    Stearine- 1

    Span 65- 0.1

    VP/Hexadecane- 3

    Dimethicone 350cp- 0.5

    PEG 150 Distearate- 0.1

    Chief Chemist/ R&D Manager at SASA Cosmetics
  • Bill_TogeBill_Toge Member, Professional Chemist
    if it were a W/O emulsion it'd float on top of the water, rather than settle to the bottom

    given how much water there is in the formula, it would also be extremely viscous and probably very difficult to shear

    and given the very low level of low-HLB emulsifiers, it would likely undergo a lot of 'bleeding' as it cooled (i.e. water separating from the bulk product)

    in short, I don't think it is W/O
    UK based formulation chemist. Strongest subjects: hair styling, hair bleaches, hair dyes (oxidative and non-oxidative) I know some stuff about: EU regulations, emulsions (O/W and W/O), toothpaste, mouthwash, shampoos, other toiletries
  • ZivBAZivBA Member

    Bill_Toge- I do agree with you.

    After I read all the comments over here, and chemicalmatt comment.

    But why in one preparation it dissolve in water and at another one it settle down in water and disperse in C12-15 Alkyl Benzoate? 

    Chief Chemist/ R&D Manager at SASA Cosmetics
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