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Issue
29 — June 2002 |
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| Issue
29 |
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 |
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| Category |
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Title |
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Authors |
| Show
Case |
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Hispagel
- glyceryl polyacrylate based thickeners as new skin care ingredients with
excellent moisturizing properties |
|
Marta
Torres, Franscsco
Fabra |
Hispagel polymer gels (1) are thickeners based on glyceryl polyacrylates. They
are multi-functional and allow product formulators to develop high-performance
cosmetic products in a fast and easy manner. They have vegetable and synthetic
raw material bases.
| Table
1: Hispagel polymer gels* - Appearance, pH-value and viscosity parameters
of Hispagel 200 and Hispagel L |
| Product |
Appearance |
pH
(100%)
|
Viscosity
(cP), 10% in water,
#5, 20 rpm, 25ºC
|
| Hispagel
200 |
Transparent,
colorless jelly |
4.7
- 5.5
|
12000
- 15000
|
| Hispagel
L |
Transparent,
colorless jelly |
4.7
- 5.5
|
14000
- 17000
|
Moisturizing properties:
Hispagel polymer gels are excellent moisturizers. Corneometric measurements showed
that they keep the skin perfectly hydrated even 7 hours after application. The
moisturizing properties of Hispagel 200 are shown in Figure 1.
Figure 1: Moisturizing properties of Hipagel 200
Ratio viscosity/concentration:
Hispagel polymers have excellent moisturizing and thickening properties. They
are ready for use, have a very good reproducibility in the final formulation and
require no neutralization. Hispagel polymers are crystal clear and are thus suitable
for application in transparent products. The viscosity of Hispagel L and Hispagel
200 is shown in Figure 2.
Figure 2: Hispagel — Viscosity versus Concentration
Ratio viscosity/pH:
Figure 3 shows the viscosity/pH ratio of Hispagel 200. The maximum stability is
found in the area between pH 5 and pH 11.
Figure 3: Viscosity/pH Ratio of Hispagel 200
Compatibility with ethanol:
The compatibility of Hispagel 200 with different amounts of ethanol is shown in
Table 2. The highest ratio of ethanol/water compatible with Hispagel 200 is around
30 percent.
| Table 2: Compatibility
of Hispagel 200 with different amounts of ethanol |
| Ratio
ethanol/water |
Hispagel
200 (g) |
Water
(g) |
Ethanol
(g) |
Appearance
|
Viscosity
(cP) |
| 0 |
10 |
90 |
0 |
Clear |
9200 |
| 20 |
10 |
72 |
18 |
Clear |
8100 |
| 40 |
10 |
54 |
36 |
Clear |
4800 |
| 60 |
10 |
36 |
54 |
Cloudy |
Breaks |
| 80 |
10 |
18 |
72 |
Precipitation |
Breaks |
| 100
|
10 |
0 |
90
|
Precipitation |
Breaks |
Summary: Properties of Hispagel polymer gel
|
|
Excellent
thickening properties |
|
|
Excellent
moisturizing |
|
|
Crystal
clear transparency |
|
|
Excellent
water solubility |
|
|
Emulsion
stabilization |
|
|
Good suspension
properties |
|
|
Excellent
temperature stability |
|
|
Very
skin compatible |
|
|
Excellent
pH stability in the range 5 to 11 |
|
|
Ethanol
compatibility up to 35 % |
Formulating with Hispagel
Transparent gels
The production of hydrophilic polymer gels is a time-consuming operation which
usually requires special equipment such as high-shear stirrers. A constant and
reproducible viscosity in the final product is not easily obtained. Hispagel makes
the production of cosmetic end products much easier because of its immediate and
excellent water solubility. Water has just to be slowly added into Hispagel while
stirring at low speed in order to avoid air incorporation.
When incorporating active substances into Hispagel systems they should be soluble
in water/glycerin so that the mixture does not become cloudy. If ionic components
are used, the viscosity may decrease.
Because of its good suspending properties Hispagel is an excellent choice to disperse
encapsulated products such as Primasphere (2) and Primasponge (3) which are carrier
systems based on chitosan carrying active ingredients such as vitamin A and menthol.
Small amounts of lipophilic substances as preservatives or perfume can be easily
solubilized with no influence on the transparency. An example of such applications
is given in Table 3 which shows a formulation for a transparent cooling gel for
legs.
Table 3: Transparent cooling legs gel
| Phase |
Component |
INCI |
% |
Function |
| I. |
Hispagel
200 |
Glycerin
(and) Glyceryl polyacrylate |
25 |
Moisturizing
gel |
 |
Water,
de-ionized |
Aqua
|
ad 100 |
|
|
Vitacell
LS 8430 |
Yeast
Extract
|
3 |
Anti-stressing
active |
| II. |
Preservative,
Parfum
|
|
q.s.
|
|
|
Eumulgin
L
|
PPG-1-PEG-9
Lauryl Glycol Ether
|
q.s. |
Solubilizer |
| III. |
Menthol-Primasponge-Small
Size
|
Encapsulated
Menthol
|
0,5 |
Encapsulated
cooling agent |
|
pH:
5,5
|
|
|
Viscosity
(mPa*s) Brookfield RTV spindle TB 20ºC, 10 rpm : 12000
|
|
Preparation
Add the water slowly on the Hispagel 200 while stirring with low speed till it
is a clear homogeneous swelling (Phase I). Add Phase II under low speed stirring.
Mix Phase III and add to the former mixture. Finally add the Menthol-Primasponge
and adjust the pH.
Hair styling gels
Hair styling gels can be easily obtained with film-forming polymers. Apart from
its ease of use, Hispagel is compatible with ethanol and does not leave dandruff-like
particles in the hair as it does not dry. Furthermore, gels made with Hispagel
200 have good spraying properties.
Creams and lotions
Hispagel can be used as a thickener and stabilizer for all kinds of O/W emulsions.
It is very suitable for cold processing since it is only required to add the oil
phase to the mixture of water and Hispagel while stirring.
For warm processing, it is possible to incorporate Hispagel either at high temperature
(up to 80º C) or at room temperature, when the emulsion is already formed.
Further examples of formulations for a light body milk (cold preparation) and
an oil-in-water soft cream are given in Tables 4 and 5.
Table 4: Light Body Milk (cold preparation)
Preparation
1. Mix phase II adding the water bit by bit slowly in the Hispagel® 200 while
stirring with slow speed 2. Mix phase I while stirring (5 min.) and add to phase
II bit by bit 3. Add phase III and adjust the pH value if necessary.
Table 5: O/W Soft Cream
Preparation:
Heat phase I to 80ºC. Heat phase II to 80ºC and add to phase I while
stirring. Allow the emulsion to cool in such a way that it remains in continual
motion. Avoid incorporation of air. If necessary homogenize with a suitable dispersion
unit (e.g. Ultra Turrax) approx. 55ºC. Add phase III and stir until complete
homogeneous swelling. Add phase IV and adjust pH.
References:
1, 2, 3: Hispagel 200, Hispagel L, Primasphere and Primasponge are registered
trademarks of Cognis Deutschland GmbH & Co KG.
* Hispagel 200, Hispagel L: INCI = glycerin (and) glyceryl polyacrylate
Contact address:
Cognis Iberia S.L. Pg.
Industrial San Vicente s/n 08755
Castellbisbal (Barcelona)
Spain
Phone (+34) 937 730 105
FAX (+34) 937 730 180
E-mail: Marta.Torres@Cognis.es - Technical
Application Cosmetics or
Francesco.Fabra@Cognis.es ext
