- CAS number:
- Ammonium Acryloyldimethyltaurate/VP Copolymer
- EINECS number:
- Non Governmental organization
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Polymeric sulfonic acid, neutralized
Copolymerization of acrylamidomethylpropane sulfonic acid and vinylpyrrolidone in the presence of ammonia and cross linking agent. Aristoflex AVC does not contain any hydrocarbon or aromatic solvents.
Aristoflex AVC is a synthetic polymer used as gelling agent for aqueous systems and as texturizer, thickener for oil-in-water emulsions. The polymer is pre-neutralized, easy to use and provides formulations with excellent yield value, corresponding to superior stability even in the absence of additional emulsifier. Emulsions formulated with Aristoflex AVC provide favourable shear thining effects and viscoelastic properties. Besides the rheological aspects, excellent sensoric properties (good skin feel, low degree of stickiness and/or tackiness) characterize formulations comprising Aristoflex AVC. Based on a polymer backbone derived from sulfonic acid, O/W emulsions can be formulated even at low pH, enabling easy incorporation of e.g. AHA’s.
Aristoflex AVC has a good compatibility with organic solvents (ethanol, acetone) and is stable towards UV radiation and high shear stress.
The amount of Aristoflex AVC used in personal care formulations is typically in the range of 0.5 – 1.2 %
Aristoflex AVC can be used to prepare O/W emulsions in both hot and cold process. Aristoflex AVC is typically added to the oil phase (comprising emollient and emulsifier), slight agitation facilitates dispersion. Any small aggregates can be broken up easily with gentle stirring. The mixing reactor should be completely dry of moisture to prevent the polymer from migrating prematurely to any water already present and becoming gummy.
Production facility requirements will usually govern the emulsification method applied. Aristoflex AVC can be used for both direct emulsification (i.e. adding the oil phase to the water phase) and inverse emulsification (i.e. adding the water phase to the oil phase). As Aristoflex AVC is pre-neutralized, no neutralisation step is required. Finally, the emulsion is homogenized with high shear mixing equipment.
Emulsions comprising Aristoflex AVC are brilliant and glossy, they provide excellent spreadability and fast absorption. The O/W emulsions are characterized by dry aesthetic feel without tackiness and are especially suitable as light, elegant formulations.
Emulsifier-free cream gels
Another special feature of Aristoflex AVC is the stabilisation of water-insoluble liquids (e.g. oil) WITHOUT using additional emulsifiers. The resulting O/W formulations are also known as pseudo-emulsions.
Using Aristoflex AVC, emulsifier-free cream-gels can be formulated, opening the door to novel, modern formulations with special rheological profiles (creamy, not ‘gelly’, non sticky/tacky) and superior skin compatibility. The resulting compositions are light and creamy, differing greatly from the gelly or gelatine-like appearance often achieved when formulating with ‘traditional’ thickeners.
The stabilising effect of Aristoflex AVC is explained by the cross-linked structure of the polymer, providing a yield value and thus ‘trapping’ the oil droplets or solids (e.g. pigments) in the water/polymer matrix.
‘Yield value’ reflects the minimum force that must be applied to the liquid to start disrupting the structure imparted by Aristoflex AVC, so flow can occur.
Aqueous gels (e.g. hair gels) are prepared by adding the water phase to Aristoflex AVC. Special care should be taken for good agitation.
The transparency of the resulting aqueous gels is depending on the amount of Aristoflex AVC used in the formulation. Concentrations of Aristoflex AVC 1% and higher provide transparent, clear gels. Slightly turbid gels can be transformed into clear formulations by addition of approx. 5% solvent, e.g. glycerin. The best gel clarity is obtained using water which is relatively free of metal ions (demineralized or deionized).
Aristoflex AVC has a good compatibility with other polar organic solvents. Hydro-alcoholic, transparent gels can be made comprising more than 50% ethanol. Typically, the water/ethanol mixture is added to Aristoflex AVC. Ethanol can be used to dissolve active ingredients while avoiding the use of solubilizers such as PEG-40 Hydrogenated Castor Oil, Polysorbate 20, or similar ingredients. In this way it is easy to prepare hydro-alcoholic gels containing perfume oils, oil-soluble UV-filters, actives (e.g. bisabolol), film formers etc. In case of high Ethanol content additional preservation is not required.
To manufacture hydro-alcoholic gels based on Aristoflex AVC the best option is to first prepare the aqueous gel, and subsequently add to the gel a solution of the active (or film former) dissolved in ethanol. The addition is preferably done by using a slow moving anchor stirrer to minimise trapping of air bubbles.
Similar to all other polyelectrolytes, e.g. carbomers, Aristoflex AVC is sensitive to electrolytes. Therefore, Aristoflex AVC is not suitable to thicken shampoos, shower gels and other systems comprising larger amounts of salt.
Aristoflex AVC can be used in a broad pH range of 4.0 – 9.0. As Aristoflex AVC is an ammonium salt, pH higher than 9.0 will release ammonia.