Gleams & Notions

Gleams Notions

August 31, 2012

A Cold Process Emulsion System

A Cold Process Emulsion System

Croda, Edison, NJ, is promoting a cold process complete emulsion system product with a catchy name of MixXin ME (INCI: Capric/caprylic triglycerides (and) glycol stearate (and) PEG-3 glyceryl cocoate (and) steareth-7).

Croda makes it easier to create emulsions.
This is a vegetable derived white paste that is readily dispersible in water, with a 10% concentration pH of 4 to 4.5. The emulsions produced are white, shiny and spread easily.

Due to their thixotropic properties, thick creams can be dispensed from pumps. Some of the stated benefits are:
  • Cold processing with only one vessel necessary;
  • Efficient emulsifier system with high internal phase loading;
  • Moisturizing base with excellent stability independent of HLB; and
  • Light, non-tacky feel even with high oil loadings.
Viscosities are dependent on concentration and pH. A 20% mix will have a viscosity of about 20,000 cps at a pH between 5 and 8. Croda recommends using the material with its OptaSense RMA-IS (INCI: Sodium polyacrylate (and) caprylic/capric triglycerides (and) paraffinum liquidum (and) tri(PPG-3myristyl ether) citrate (and) sorbitan laurate (and) trideth-6) if increased viscosity is desired.

MixXin ME is compatible with anionics, some cationics, nonionics, silicones, essential and vegetable oils, organic sunscreens, vitamins and cosmetic active ingredients. It has limited compatibility with salts, some cationics, inorganic sunscreens, and very hard water. As a primary emulsifying base, 10 to 35% is used. If used with OptaSense RMA-IS, 4-10% would be sufficient.

Oil-in-Water Emulsions
When making an oil-in-water emulsion, the use of up to 80% polar oils in the internal phase is possible. Among the oils that can be emulsified at high levels are mineral and paraffin oils, and simple esters. Lanolin, complex esters, petrolatum, silicones and vegetable oils are emulsified at medium levels. MixXin ME can be successfully used in creams and lotions, cationic conditioners, and physical and organic sunscreens.

When formulating, the following should be considered:
  • If used as the sole oil phase of the formula, other ingredients may be added at the same time. pH and viscosity are adjusted last.
  • When emulsifying, add the water phase slowly to the MixXin ME phase. Moderate propeller speed is recommended—high shear homogenization is not.
  • Highly viscous materials like petrolatum and lanolin should be mixed with MixXin ME before adding the water.
  • When using cationics or inorganics such as TiO2 and ZnO, the MixXin ME phase should be pre-neutralized to a pH above 7.2 by a strong base before the addition.
  • Any alkali can be used to adjust the pH, but triethanolamine is recommended to avoid the risk of over-neutralization.

The following moisturizing cream formula requires no heating step.

Light Moisturizing Cream
Ingredients: %Wt.
Part A
Water 75.6
MixXin ME 8.0
Ethylhexyl pelargonate 4.0
Echium plantagineum seed oil 5.0
PPG-3 benzyl ether 3.0
2-ethylhexanoate Glycerin 0.5

Part B
Aqua (and) glycerin (and)steareth-20 (and) palmitoyl tetrapeptide-7 2.0
Thermus thermophillis ferment(and) glycerin 1.0
Methylisothiazolinone 0.1
Part C
OptaSense RMA-IS 0.8

Combine all A ingredients, except water, with mixing. Add water slowly with moderate mixing until homogenous.
Add B ingredients individually with mixing.
Add C and mix until homogenous.
The pH was 5.25 and the viscosity was 19,000 cps.

Harvey M. Fishman

Harvey Fishman has a consulting firm in Wanaque, NJ, specializing in cosmetic formulations and new product ideas, offering tested finished products. He has more than 30 years of experience and has been director of research at Bonat, Nestlé LeMur and Turner Hall. He welcomes descriptive literature from suppliers and bench chemists and others in the field.