Paint Rheology Modifiers: HEUR, HASE and Selection
Compare paint rheology modifiers by coating system and shear requirements. Evaluate HEUR, HASE and mineral options with sagging, leveling and storage tests.
Overview
Rheology modifiers control how a paint flows at different shear conditions. Select a modifier by the coating system, application method and required viscosity profile. A thicker paint at one measurement point is not automatically better at storage, brushing, spraying and leveling.
Define the required viscosity profile
BYK’s rheology guide distinguishes the requirements of storage, layer thickness and application, and stresses compatibility with the system’s polarity. Start with the problem and the test conditions rather than a target viscosity without a method.
| Requirement | Comparison question | Trial observation |
|---|---|---|
| Storage and suspension | What response is needed at rest and low shear? | Settling, separation and recoverability under defined storage conditions |
| Application | What happens at the relevant brush, roller or spray conditions? | Handling, transfer and film build using the intended method |
| Sagging and leveling | How quickly should the structure recover after application? | Vertical sag resistance and surface leveling tested together |
| Batch consistency | Are measurements made after the same conditioning and mixing history? | Repeat measurements at defined temperature and time |
HEUR, HASE and other families
The chemistry is one part of selection. BYK presents both associative and mineral-based options for different systems. Dow’s HASE product description describes alkali swelling combined with hydrophobic associations. The existence of these families does not establish a universal ranking between them.
| Family to investigate | Candidate information required |
|---|---|
| HEUR associative thickener | Binder and additive compatibility, supported shear profile and grade-specific instructions |
| HASE modifier | Appropriate system and activation conditions in the supplier guidance, with a formulation trial |
| Clay or other mineral-based modifier | System polarity, incorporation or activation instructions and required appearance |
Do not transfer results from one HEUR research formulation to HASE or clay. The property examples and reference codes on this page concern the previously documented HEUR study or named supplier product, not specifications for every rheology modifier.
Compare the complete formulation
Keep the control binder, pigments, dispersant and surface additives recorded. Specify the addition basis, mixing sequence, conditioning time and temperature. Changing both the binder and thickener at once makes the result harder to interpret.
ASTM D2196 is the existing rotational-viscometer reference for non-Newtonian properties; record the method and conditions with the result. Select any additional application or high-shear testing to suit the product specification. A single viscosity value cannot stand in for every shear range.
Troubleshoot before increasing dosage
Check whether the defect concerns application, pigment dispersion or storage. Use dispersant selection for pigment-related issues and wetting agents for substrate coverage. For liquid separation and shelf-life questions, follow the existing storage-stability and syneresis guide.
Define acceptance limits for the actual coating: viscosity profile, sagging, leveling, film appearance and storage behavior as relevant. Request the candidate TDS and SDS, then share binder system, application, test conditions, observed defect, quantity and destination for a useful enquiry.
Content reviewed: 8 October 2026. BYK and Dow support the family-selection framework. The HEUR research context below is retained as a specific example, not a general dosing or performance guarantee.
Documented HEUR research example
The following observations describe the cited 2024 study and its test formulations. The numeric property rows and illustrative draft codes must be read within this scope. The HIRESOL 852 dosage reference is a separate named-product example; confirm its current TDS before use.
How it’s used
A 2024 peer-reviewed study synthesized ten HEUR (hydrophobically modified ethoxylated urethane) thickener variants by varying their hydrophilic PEG segment (molecular weights of 2,000-10,000 g/mol), their hydrophobic end-group (C5-C12 chain lengths), and their diisocyanate linker (HDI, IPDI, or H12MDI). Bulkier diisocyanates and longer hydrophobic tails produced significantly higher viscosities and lower “critical bridging thresholds” — the point at which the hydrophobic segments start linking latex particles into a viscosity-building network. Less hydrophobic variants behaved in a largely Newtonian way with low viscosity, while more hydrophobic variants showed clearly pseudoplastic (shear-thinning) behavior with much higher viscosity.
Limitations — when it isn’t the right choice
- A more strongly hydrophobic HEUR structure improves sag resistance but weakens leveling — you can’t maximize both with the same molecule. The same 2024 study found that the more pseudoplastic HEUR variants gave superior resistance to sagging on vertical surfaces, but this came at the cost of compromised leveling (the coating’s ability to flow out into a smooth, even film after application). A balanced combination of both properties was only achieved with intermediate molecular weights, in the 14,000-23,000 g/mol range — below and above this range, the coating tended to favor one property at the expense of the other. The study also found that the length of the hydrophilic PEG segment had only a marginal effect on viscosity between 8,000 and 23,000 g/mol, but a pronounced effect once it reached 33,000 g/mol in actual paint formulations. This means selecting a rheology modifier isn’t a matter of choosing “more thickening power” — it requires balancing sag resistance against leveling for the specific application. These findings are specific to HEUR-type associative thickeners; other rheology-modifier chemistries (such as HASE or clay-based modifiers) would need separate verification.
Content updated:
Key Applications
The material's role changes by industry — click any industry to see its full page.
Physical Properties
| Property | Typical Value | Note |
|---|---|---|
| Physical Form | Liquid (aqueous solution) | HIRESOL 852 reference only; confirm the current grade TDS. Definitional |
| Chemistry Type | HEUR — hydrophobically modified ethoxylated urethane (nonionic) | Documented HEUR example only; not a family-wide specification. Definitional |
| PEG Segment Molecular Weight | ≈ 2,000-10,000 g/mol | Documented HEUR example only; not a family-wide specification. Typical published value — Tzortzi et al., Industrial & Engineering Chemistry Research (ACS), 2024 |
| Hydrophobic End-Group Chain Length | C5-C12 | Documented HEUR example only; not a family-wide specification. Typical published value — Tzortzi et al., Industrial & Engineering Chemistry Research (ACS), 2024 |
| Typical Dosage | ≈ 0.2-2.0% by weight of total formulation | HIRESOL 852 reference only; confirm the current grade TDS. Typical published value — HIRESOL 852 Technical Data Sheet, Hankuck Latices |
These are typical published values for the material in general, not a certificate of analysis (COA) for a specific shipment. Actual per-batch values are set by the COA accompanying supply.
Grades
Grade and Specification Guide
These reference codes illustrate grade categories and specifications for comparison and selection. The commercial grade and final specification are determined by your application requirements, the technical data sheet and the batch certificate of analysis.
Standards & Technical References
Every claim on this page traces back to a verifiable reference:
- Tier 1Industry StandardASTM D2196-20(2026) — Standard Test Methods for Rheological Properties of Non-Newtonian Materials by Rotational Viscometer
- Tier 2University/ResearchTailoring Waterborne Coating Rheology with Hydrophobically Modified Ethoxylated Urethanes (HEURs): Molecular Architecture Insights Supported by CG-MD Simulations, Tzortzi et al., Industrial & Engineering Chemistry Research (ACS), 2024, Vol. 63, Issue 22, pp. 10009-10026
- Tier 3Global SupplierHIRESOL 852 Urethane Thickener Technical Data Sheet, Hankuck Latices
- Reviewed 2026-10-08Primary sourceBYK — Rheology additives — https://www.byk.com/en/product/rheology-additives
- Reviewed 2026-10-08Primary sourceDow — PRIMAL TT-935 HASE rheology modifier — https://www.dow.com/en-us/pdp.primal-tt-935-rheology-modifier.136382z.html
- Reviewed 2026-10-08Primary sourceASTM — D2196-20(2026) official scope — https://store.astm.org/standards/d2196
- Reviewed 2026-10-08Primary sourceACS — HEUR architecture study (2024) — https://doi.org/10.1021/acs.iecr.4c00253
Frequently Asked Questions
What are rheology modifiers?
Rheology modifiers are additives used to control the viscosity and flow behavior of paints and coatings, particularly their non-Newtonian behavior — how viscosity changes under shear. The industry-standard way of measuring this is ASTM D2196.
How do HEUR rheology modifiers control paint viscosity?
They work through a hydrophobic bridging network: their hydrophobic segments link latex particles together past a certain "critical bridging threshold," building shear-dependent viscosity — allowing sag resistance at rest without uniformly thickening the coating.
What standard is used to measure a coating's rheological properties?
ASTM D2196, which covers apparent viscosity along with shear-thinning and thixotropic properties using a rotational viscometer across a shear rate range of 0.1 to 50 s⁻¹.
What did the documented HEUR study show about sagging and leveling?
In the documented HEUR study, more hydrophobic structures favored sag resistance at the expense of leveling, with balance at intermediate molecular weights. This is a study-specific result, not a universal limit for every thickener or coating system.
Is the published HIRESOL 852 dosage a rule for all HEUR thickeners?
No. The 0.2–2.0% range in the page's HIRESOL 852 reference concerns that named product, not a general recipe. Check the current grade data sheet and addition basis, then test the actual coating system.
Do the HEUR study findings apply to other rheology-modifier chemistries?
No. These findings are specific to HEUR-type associative thickeners; other rheology-modifier chemistries (such as HASE or clay-based modifiers) would need separate verification.
Related Materials
