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D1455-17 – Standard Test Method Technical Guide
The ASTM D1455-17 (Reapproved 2023) standard provides a definitive method for evaluating the 60° specular gloss of dried emulsion floor polish films. This standardized approach ensures consistent quality assessment by precisely defining the apparatus, substrates, and application techniques required for reproducible results across different testing laboratories.
🔬 Scope, Significance, and Key Terminology
This test method is specifically designed to measure the 60° specular gloss of emulsion floor polish films after application to a designated substrate. The measurement focuses on the specular reflection, which is the mirror-like reflection of light from the film surface. According to the standard, specular gloss is defined quantitatively as the ratio of reflected to incident light, multiplied by 1000, under specific geometric conditions.
The significance of this measurement lies in its ability to differentiate the gloss characteristics of various polish formulations. However, it is important to note that specular gloss measurements may not always perfectly correlate with visual glossiness rankings, particularly for extremely high-gloss or low-gloss finishes. In such cases, the standard recommends a supplementary measurement at a 20° angle, performed in accordance with Test Method D523, which can provide better definition of gloss.
⚙️ Equipment, Substrates, and Testing Procedure
⚠️ Important Substrate Selection Note: While black glass is the preferred substrate for its highly reproducible plane surface (refractive index 1.567), it must not be used when a hazy film is produced by the polish. In such cases, standard vinyl composition tile should be substituted to ensure accurate measurement.
The core apparatus required includes a glossmeter conforming to Test Method D523 using a 60° angle, and a floor polish applicator conforming to Test Methods D1436. The choice of substrate significantly impacts results:
| 🟦 Substrate Type | 📏 Key Specifications | 🎯 Recommended Application |
|---|---|---|
| Black Glass | Refractive Index of 1.567 | General use; provides best agreement of results |
| Official Vinyl Composition Tile | New and unused | When hazy film is produced; simulating real-world application |
💡 Procedural Tip for Consistency: The standard highlights that Method A described in Test Methods D1436, which utilizes an automatic dip coater, can be expected to yield better agreement of results. For reliable comparison across different tests or batches, the same application method must always be used.
The testing procedure is straightforward: first, apply the floor polish to the chosen substrate strictly in accordance with Test Methods D1436. Once the film is dried, determine the specular gloss at 60° using the calibrated glossmeter, following the operational protocol defined in Test Method D523.
❓ Frequently Asked Questions
🔍 What is the primary purpose of ASTM D1455-17?
The standard provides a method for the determination of the 60° specular gloss of dried films of emulsion floor polish applied to a substrate, allowing for standardized quality control and performance comparison.
💡 Why is a 20° measurement angle sometimes necessary?
Extremely high-gloss or low-gloss polishes may not be sufficiently differentiated at a 60° angle. According to the standard, measuring at a 20° angle in accordance with Test Method D523 can provide better definition of gloss for these specific ranges.
⚡ When should I use vinyl composition tile instead of black glass?
Black glass should not be employed as the substrate when the sample being tested produces a hazy film. In such cases, official vinyl composition tile, which is new and unused, is the recommended alternative to ensure accurate measurement.
📌 How does the application method affect the test results?
The method of application is critical. The standard explicitly states that for comparison of results, the same method of application must be used. Method A, using the automatic dip coater, is noted for providing better agreement of results.