Addivion SURF 41 is a liquid rheology additive based on a solution of modified urea, formulated for medium-polarity solvent-borne and solvent-free coating systems as well as PVC plastisols and ambient-curing resin systems. After being stirred into the formulation, the additive generates a three-dimensional network structure that produces highly thixotropic flow behavior, improving anti-sagging and anti-settling performance without impairing leveling. Post-addition is possible, giving formulators flexibility to adjust viscosity late in the production process.
Addivion SURF 41 Overview
Addivion SURF 41 belongs to the family of urea-based liquid rheology additives, in which a modified urea solution reacts with the surrounding binder system to form a three-dimensional thixotropic network. This network structure is highly effective at preventing sedimentation and increasing anti-sagging properties, while generally increasing viscosity only at low shear rates so that application properties at high shear rates, such as brushing or spraying, remain largely unaffected.
The product is recommended for incorporation into medium-polarity systems; its rheological effectiveness builds up over time and polarity and can generally be evaluated two to four hours after incorporation. The additive can be added into the millbase during initial formulation or introduced afterward as a post-additive to fine-tune viscosity, offering considerable flexibility in production workflows.
Key Features
- Modified urea chemistry: Addivion SURF 41 is built on a solution of modified urea that forms a three-dimensional network structure within the formulation.
- Strong anti-sagging and anti-settling performance: The additive generates highly thixotropic flow behavior, improving resistance to sagging and pigment settling.
- Minimal impact on leveling: Because the additive primarily raises viscosity at low shear rates, high-shear application properties and leveling are largely preserved.
- Flexible post-addition: The additive can be incorporated during initial formulation or added later as a post-additive to adjust viscosity.
- Broad system compatibility: Addivion SURF 41 performs well in solvent-borne coatings, solvent-free systems, PVC plastisols, and ambient-curing epoxy, polyurethane, and acrylate resins.
Typical Applications
Addivion SURF 41 is primarily used as a thixotropic flow control additive in medium-polarity solvent-borne and solvent-free industrial coatings, where it prevents sagging and settling while preserving good leveling. It is also widely applied in PVC plastisols, where it accelerates manufacturing and processing, minimizes flooding and floating in pigmented systems, and improves control of the coating profile during gelling.
Beyond coatings and plastisols, the product is highly suited to preventing sedimentation in filled, reactive ambient-curing resin systems such as epoxy, polyurethane, and acrylate resins, and in some polyester resins, where the resulting network structure also improves deaerating properties. For complementary pigment wetting and dispersion in these filled systems, formulators often evaluate Addivion DISP 00 alongside this grade.
Technical Specifications
- Composition: Solution of a modified urea
- Active substance: 52%
- Density (20°C): 1.13 g/ml
- Solvent: N-Methylpyrrolidone
- Flash point: 91°C
- Function: Thixotropic rheology additive for anti-sagging and anti-settling control
Urea-Based Thixotrope Chemistry & Network Formation
Urea-based rheology additives such as Addivion SURF 41 build viscosity through a distinctly different mechanism from clay or fumed silica thickeners: the modified urea reacts in situ with amine or other reactive groups in the binder system to precipitate a fine, three-dimensional network of urea crystals throughout the formulation. Because this network forms after incorporation rather than being pre-built into the additive, the rheological effect develops gradually, typically becoming fully evident two to four hours after mixing, with the exact timing depending on system polarity and reactivity.
Formulators should note that the additive is optimized for medium-polarity systems; more nonpolar formulations may require an alternative urea-based grade, while highly polar or aqueous systems typically call for a different chemistry altogether. When used alongside metal driers or accelerators, discoloration or delayed curing can occur due to the formation of metal complexes, so compatibility should be confirmed through small-scale trials in systems sensitive to yellowing or in reactive, catalyzed formulations.
Storage Recommendations
- Store in the original, tightly sealed container, protected from moisture; the product is moisture sensitive and should be kept dry.
- Recommended storage temperature: 0-30°C.
- Shelf life: Up to 24 months in the original, unopened packaging when stored under recommended conditions.
- Slight turbidity may develop during storage but does not affect rheological effectiveness.
Documentation & Compliance
Each shipment of the product is supported by standard quality and compliance documentation to help customers manage incoming inspection, formulation approval, and downstream regulatory reporting.
- Certificate of Analysis (COA): Provided per batch
- Safety Data Sheet (SDS): Mandatory prior to handling
- Labels: Prepared in accordance with applicable regulations
- Industrial and professional use only
Formulation Guidance
Recommended addition levels vary by application and desired effect: in coatings and ambient-curing resin systems, 0.2-1% of total formulation is typical to prevent settling, while 0.5-2% is recommended to increase anti-sagging properties. In PVC plastisols, dosage is expressed per hundred resin (phr): 0.1-0.5 phr to prevent settling and floating, and 0.3-1 phr to prevent sagging, with doses up to 3 phr possible in exceptional cases. These levels serve as a starting point, with optimal dosage determined through laboratory trials for the target system.
The additive should be added while stirring using moderate shear forces to ensure homogeneous, rapid distribution; precise temperature control is not required. For plastisols, the product should be post-added slowly under stirring, with the initial thixotropic structure typically forming within four hours, though re-establishment after shearing occurs almost instantly. For a complementary silicone-free air release additive in the same filled resin systems, formulators may wish to evaluate Addivion SURF 53A.
Packaging & Logistics
- Packaging: Approved industrial packaging
- MOQ: Subject to packaging configuration
- Lead time: Indicative lead time, to be confirmed upon order acceptance
- Incoterms: Quoted case by case
Addivion SURF 41: Safety & Handling
Addivion SURF 41 should be handled in accordance with standard industrial hygiene practices for coatings and resin additives. Users are advised to review the Safety Data Sheet prior to handling and to implement appropriate personal protective equipment and engineering controls as specified therein. As with all rheology additives, small-scale compatibility and dosage trials are recommended before full-batch formulation to confirm thixotropic performance and to check for any effect on color, curing, or storage stability in reactive systems.
Safety Data Sheet and destination-compliant labeling information for the product are available upon request. For related additive options, see also Addivion SURF 53A and Addivion DISP 00.