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D4287-00 – Standard Test Method Technical Guide
📐 Scope and Applicability
This test method, designated ASTM D4287-00, determines the viscosity of paints, varnishes, and related products at a constant shear rate of 12,000 s⁻¹. It is applicable to both Newtonian and non-Newtonian fluids. However, paints that dry very rapidly may not yield reproducible results, particularly at elevated temperatures. The standard uses SI units, with viscosity expressed in pascal-seconds (Pa·s), where 1 Pa·s = 10 poise (P).
| ⚙️ Parameter | 📏 Specification |
|---|---|
| Shear Rate | 12,000 s⁻¹ |
| Viscosity Range (Option 1) | 0 to 10 P (0 to 1 Pa·s) |
| Viscosity Range (Option 2) | 0 to 5 P (0 to 0.5 Pa·s) |
⚠️ Warning: Fast-drying paints and elevated temperature measurements may give poor precision due to volatile loss and drying. Use caution when interpreting results.
⚙️ Equipment and Shear Rate Selection
The apparatus required is a cone/plate viscometer with a cone and speed combination that produces a shear rate of exactly 12,000 s⁻¹. The viscometer must have a viscosity measurement range of either 0 to 10 P or 0 to 5 P. For higher-viscosity materials, alternative cones and speeds may be used upon mutual agreement between producer and user, but these may result in lower shear rates that are not representative of typical application conditions. The instrument must be zeroed according to manufacturer specifications, using water or a low-viscosity solvent such as xylene.
💡 Technical Note: When zeroing, use a consistent liquid for all tests to ensure accuracy. Unit conversion: 1 P = 0.1 Pa·s, and 1 cP = 1 mPa·s.
| 📐 Related Standard | 🟦 Description |
|---|---|
| D1210 | Fineness of Dispersion of Pigment-Vehicle Systems by Hegman-Type Gage |
| D3925 | Practice for Sampling Liquid Paints and Related Pigmented Coatings |
| D4958 | Test Method for Comparison of the Brush Drag of Latex Paints |
📊 Significance and Applications
The viscosity value obtained from this test method provides information about flow properties under high-shear conditions similar to those encountered during brushing (see Test Method D4958), spraying, electrostatic disk coating, or roll coating. This test method is suitable for all paints and varnishes, but it is more reproducible for materials with finer pigment dispersions as determined by Test Method D1210. Understanding high-shear viscosity aids in formulating coatings for optimal application performance.
❓ Frequently Asked Questions
🔍 What is the required shear rate for this test?
The standard specifies a shear rate of 12,000 s⁻¹.
💡 Can this method be used for all types of paints?
Yes, it is suitable for both Newtonian and non-Newtonian paints, but reproducibility is higher for paints with fine pigment dispersions. Fast-drying paints may require special consideration.
⚡ What viscosity ranges are covered?
The viscometer should measure either 0 to 10 poise or 0 to 5 poise at 12,000 s⁻¹, which corresponds to 0 to 1 Pa·s or 0 to 0.5 Pa·s in SI units.
📌 How does this test relate to paint application?
It simulates high-shear conditions during brushing, spraying, or roll coating, providing data on flow properties like brush drag and leveling.