RHEOBYK 405 is a liquid rheology additive for solvent-borne coating systems. It enhances the effectiveness of pyrogenic fumed silica, facilitating its incorporation, preventing separation, and stabilizing or increasing thixotropic behavior. It is compatible with polyesters, acrylates, and alkyds, and is used in solventborne coatings. The product is brown in color and improves rheology while also acting as a dispersant.

Chemical Family: Carboxylic Acid Amide

Compatible Polymers & Resins: Acrylates, Alkyds, Polyesters

Physical Form: Liquid

End Uses: Solventborne Coating

Enhanced TDS

Identification & Functionality

Features & Benefits

CASE Ingredients Features

Applications & Uses

Compatible Polymers & Resins
Coating End Applications
Use Level
20% - 40%
Application Information

Coatings Industry

Special Features and Benefits

  • RHEOBYK-405 acts as a wetting and dispersing additive and makes it easy to incorporate pyrogenic fumed silica in the coating. It increases or stabilizes the thixotropic behavior. The improved rheological effect is particularly noticeable in clear coatings as the incorporation of the fumed silica does not usually occur at the same high shear forces as for pigmented systems.
  • The additive reduces or prevents the separation of pyrogenic fumed silica in the coating.
  • RHEOBYK-405 is specifically designed for solvent-borne coating systems based on polyester, acrylate, and alkyd binders that contain pyrogenic fumed silica. The fumed silica should be at least partially hydrophilic.
  • Thixotropic binders gain increased thixotropy when additionally dosed with RHEOBYK-405.
Recommended Levels
  • 20-40% additive (as supplied) based upon the pyrogenic fumed silica.
  • The above recommended levels can be used for orientation. Optimal levels are determined through a series of laboratory tests.

Properties

Color (Properties)
Physical Form
Typical Properties
ValueUnitsTest Method / Conditions
Flash Point29°C-
SolventsXylene/alkylbenzenes/isobutanol(5/4/1)--
Non Volatile Matter52%-
Density0.93g/ml-
SDS Physical and Chemical Properties
ValueUnitsTest Method / Conditions
Kinematic Viscosity (at 40°C)228mm²/s-
Ignition Temperaturemin. 200.00°CDIN 51794
Density (at 20°C)0.925g/cc4 (Oscillating U-tube, at 20°C)
Lower Explosion Limit1%V-
Explosion Limits (Upper)10.7%V-
Immiscible inWater--
Flash Point29°C48 (Abel-Pensky)
Vapor Pressure (at 20°C)max. 7hPa-
Initial Boiling Point106°CEstimated
Melting Pointmax. 0°CEstimated
pH Value (at 20°C, 1% Concentration)6-Universal pH Value Indicator
OdorNot significant--
AppearanceLight brown liquid--
Compatibility

Solution of polyhydroxycarboxylic acid amides

Incorporation

RHEOBYK-405 can be added to the formulation before or after dispersion of the pyrogenic fumed silicas whilst stirring.

Storage & Handling

Storage and Transportation

Separation or turbidity may occur. Warm to 20-30 °C and mix well. Product efficiency is not affected.