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Application of Acrylates /Beheneth-25 Methacrylate Copolymer (Tinovis® GT Clear) as a Rheology Modifier, Suspending Agent and Polymeric Emulsifier in Cosmetic Formulations

IP.com Disclosure Number: IPCOM000026710D
Publication Date: 2004-Apr-06
Document File: 7 page(s) / 25K

Publishing Venue

The IP.com Prior Art Database

Abstract

Tinovis® GT Clear, an acrylates /beheneth-25 methacrylate copolymer can be used as an efficient thickener for suspending solid materials in clear and opaque gel and surfactant systems at relatively low pH levels for added formulation flexibility. Tinovis® GT Clear also thickens and stabilizes emulsions and works as a polymeric dispersant allowing formulators to create a variety of stable emulsions products.

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Application of Acrylates /Beheneth-25 Methacrylate Copolymer (Tinovis® GT Clear) as a Rheology Modifier, Suspending Agent and Polymeric Emulsifier in Cosmetic Formulations

Acrylates /Beheneth-25 Methacrylate Copolymer(Tinovis® GT Clear) is a new product manufactured by Ciba Specialty Chemicals. It is a hydrophobically modified (long C22 alkyl chain) alkali activated aqueous emulsion, with the acrylate backbone modified to allow thickening at pH >6 whilst maintaining the solids content at 30% active polymer.

The development of viscosity in aqueous solutions of Tinovis® GT Clear occurs on the addition of a suitable base. The acid groups present in the alkyl backbone become ionised and structuring occurs by electrostatic repulsion. The presence of the hydrophobically modified associative group enhances the rheology modification by the formation of inter- and intra-molecular micelles, which provide extremely high apparent viscosities at very low shear rates. The presence of such groups also allows association with other hydrophobic moieties that may be present in personal care formulations.

The combination of the optimised acrylic backbone, hydrophobic associative monomer and the level of cross-linking in the polymer results in a shear-thinning non-thixotropic rheology modifier with excellent yield value and suspension characteristics. The Brookfield yield value for a 1% aqueous dispersion of Tinovis® GT Clear at pH 6 is 1400 Pa, whereas that for a Steareth-10 Allyl Ether / Acrylates Copolymer (Ciba Salcare SC80) is in the region of 8 Pa at pH 7.5. This allows application of Tinovis® GT Clear in systems containing a variety of particulates.

The structure of the polymer system accounts for the rheology of the product on application. Acrylic thickeners are typically shear thinning, where the apparent viscosity falls on the application of shear due to disruption of the entangled chains. As expected from associative thickening, application of very low levels of shear can cause a slight increase in apparent viscosity, as the associative groups are able to move together under this slight force. The viscoelastic nature of the polymer can be characterised by examining the storage modulus (G’) and the phase angle between viscous and elastic behaviour (expressed as tan delta). The storage modulus gives some indication of the strength of the gel network, whereas the tan delta shows some indication of the structure of the system at different shear rates. The tan delta and G’ values for this system show an improvement in structure and strength compared to other commercially available alkali activated emulsions.

Tinovis® GT Clear is supplied as a low viscosity liquid which can be easily pumped, and provides an advantage over other solid grade thickeners and stabilizers such as Carbomer, powdered Guar and Xanthan Gums which require special handling, mixing and solubility parameters.

Tinovis® GT Clear can be used in many personal care applications, i...