Novel Thickening Agent Promises Better Stability, Faster Processing, and Easier Clean-up

The Procter & Gamble Company

Traditionally, non-aqueous suspensions such as inks, paints, and coatings have been thickened with materials such as treated clays, silica, and polymers. These thickeners, called structurants, often rely upon interactions with formula components to do their job, resulting in non-aqueous structures that can separate easily, be unstable, and be highly sensitive to any formula variation.

However, Procter & Gamble has developed a novel thickening agent that represents a radical departure from the old ways of thickening non-aqueous systems. Called CLASS (Crystalline LAS Structurant), it is a particulate structurant composed primarily of a common anionic surfactant, linear alkyl benzene sulfonate (LAS) and an alkali metal sulfate. Unlike many other structurants, P&G´s patented CLASS material doesn´t rely on interactions with formula components -- it builds structure by interacting with itself. For this reason, it forms stable, non-aqueous compositions that are amazingly insensitive to pH and electrolytes.

This unique structuring particle can be delivered as either a dry-flake product or a pre-dispersed gel in a compatible solvent suitable for a wide range of applications. It builds a highly shear-thinning but rapidly recovering particulate structure in non-aqueous compositions. Because it is also water-soluble, the structure breaks down upon contact with water or surface moisture, which could enable faster, easier clean-up when used in such applications as paints and inks. Furthermore, CLASS in gel form displays remarkable stability at high temperatures, promoting longer shelf-life and reliable application in harsh environmental conditions.

Numerous Benefits

CLASS is a breakthrough technology that is proving effective in suspending a variety of materials, including heavy solids, light materials, and gases. In addition to stability and water-solubility, it holds several other distinct advantages over conventional thickeners. First, CLASS can be easily activated by simple dispersion without the need for additional activators, heating, or complicated processing. Second, CLASS is easy to make from common and inexpensive commercial materials, which will make it very cost effective compared to other non-aqueous structuring systems.

In summary, Procter & Gamble´s new CLASS material demonstrates a number of advantages over conventional thickeners:

• Improved viscosity stability, even at high temperatures
• Greater formula flexibility
• Superior suspension of heavy materials
• Easier processing through simple dispersion
• Better anti-sag/anti-settling properties
• Water-soluble for easy clean-up

The clear advantage of P&G´s CLASS over traditional thickeners could make it ideal for a broad range of applications including agricultural chemicals, coatings, paints, inks, polishes, and stripping compounds, to name a few. For instance, CLASS could improve the stability and clean-up properties of non-aqueous paints, stains, and coatings and provide an economical alternative to current structurants. In water dispersal applications, the surfactant component in CLASS enables a smaller droplet size and more efficient spreading of the product when dispersed in water, making it ideal for pesticides and other agricultural chemicals. Water solubility makes it easy to wash away without residue and promotes mixing of water and oil-based products. The printing industry could use CLASS to produce non-aqueous inks demonstrating superior anti-settling, anti-misting, and non-flocculating properties with improved wet-out on printed surfaces. Liquid toner and jet inks could benefit from the thickening and yield stress generating properties of CLASS and its superior stability at elevated temperatures. These are but a few of the potential applications for this breakthrough technology. CLASS technology is currently available for licensing from Procter & Gamble.