AEROSOL SHAVE CREAM

Composition and Function:

Most shaving cream consists of a soap solution released from a pressurized can in a foamy state for spreading on the shaver's face with fingers or brush.

The soap is generally a combination of triethanolamine, stearic acid and/or stripped coconut fatty acid at a concentration of about 7% to 12%. Liquefied petroleum hydrocarbons or fluorinated hydrocarbons can be used as propellants. The most popular hydrocarbon systems are blends of about 87% isobutane and 13% propane used at levels of 3% to 7%.

Formulation:

A wide range of emollients, moisturizers and foam stabilizers can be added to improve the esthetic properties of a basic shave cream formula. In formula SK-17, ARLAMOL(r) F PPG-11 Stearyl Ether improves razor glide and adds emollience to the formula. Surfactants like BRIJ(r) 98 Oleth-20 improve the density and stability of the foam without contributing to skin irritation. Sorbitol Solution, U acts as a humectant to hold moisture on the face and keep the lather from drying out during the shave.

Formula SK-17
    AEROSOL SHAVE CREAM   %, Weight
A   Stearic acid, triple pressed   9.0
    BRIJ 98   2.0
    ARLAMOL F   2.0
B   Water   67.4
    Triethanolamine   4.6
    Sorbitol Solution, USP   10.0
C   Preservative   q.s.
D   Hydrocarbon Propellant A-46   5.0
        100.00

Preparation:

Heat (A) to 75°C. Add (B) to (A) slowly with agitation while maintaining temperature at 70-75°C After 15 minutes at this temperature, cool. Add (C) about 50°C Replace water lost by evaporation. Package in aerosol containers. Pressurize with (D).

Formula SK-18 offers an alternative to the soap type product. This product is nonionic and could be prepared at a neutral or acidic pH.. Benefits offered by this formula include low irritation, better rinsibility and compatibility with a wide range of other ingredients. The foam, itself, is rich and dense.

Formula SK-18
    NONIONIC AEROSOL SHAVE CREAM

This is a dense, rich, economical foam with a pH

that can be varied over a wide range.

   %, Weight
A   Cetyl alcohol   4.30
    BRIJ 721   2.20
B   Water, deionized   93.25
    Sorbic Acid   0.17
C   Fragrance   0.08
        100.00

Preparation:

Heat (A) to 70°C and (B) to 75°C. Add (B) to (A) slowly with good agitation. Add (C) at 35°C Adjust pH to 5.5 with dilute NaOH. Add water to compensate for evaporation. Continue agitation until viscosity is low enough to pour.

Pressured:

Above concentrate 160.0g

Difluoroethane 5.0g

Gel shave creams are essentially soap-type formulas packaged in a Sepro-Can aerosol container (Continental Can Co.) The gel concentrate contains a low level of propellant. When the gel is expelled from the can, this propellant volatilizes on warm skin surfaces and produces a foam. Nonionic surfactants like BRIJ 98 Oleth-20 stabilize the foam.

Formula SK-19
    GEL SHAVE CREAM   %, Weight
A   Palmitic acid   6.50
    Stearic acid   2.25
    BRIJ 98   1.00
B   Water   34.20
    Sorbitol Solution, USP   10.00
C   Water   10.00
    Triethanolamine   4.75
D   Hydroxypropyl cellulose solution

(1.0% W/W in water)

  7.50
    Propylene glycol   3.30
E   Carbomer 934 solution

(1.5%, W/W in water)

  15.00
F   Propylene glycol dipelargonate   2.75
    n-Butane   0.55
    n-Pentane   2.20
        100.00

Preparation:

Heat (A), (B) and (C) to 60°C. Add (B) to (A) with gentle agitation. Add (C) slowly to (AB) with gentle agitation. Add (D) and (E) separately to this soap base and stir until homogenous. Mix ( at 5°C. All ingredients are transferred to a pressurized vessel and mixed at 7 to 10 psig. This mixture is packaged in a suitable aerosol can. The can is pressurized from the bottom with a mixture of propane and isobutane having a vapor pressure of approximately 46 psig.