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D5736-95 – Standard Test Method Technical Guide
📐 Scope and Terminology
This test method describes the measurement of thickness of highloft nonwoven fabrics. For thickness of nonwoven fabrics other than highloft, see Test Method D5729. Highloft nonwoven fabrics are low‑density fiber network structures characterized by a high ratio of thickness to mass per unit area. The standard specifies that values stated in SI units are to be regarded as the standard; the inch‑pound units given in parentheses may be approximate.
Key terminology includes definitions for highloft nonwoven fabric, nonwoven fabric, pressure, and thickness. Pressure is defined as the force per unit area, expressed in pascals (Pa), newtons per square metre (N/m²), or pound‑force per square inch (psi). Thickness is the distance between the upper and lower surfaces of the material, measured under a specified pressure.
| 🟦 Term | 📏 Definition |
|---|---|
| Highloft Nonwoven Fabric | A low‑density fiber network structure with a high ratio of thickness to mass per unit area. |
| Nonwoven Fabric | A textile structure produced by bonding or interlocking of fibers through mechanical, chemical, thermal, or solvent means. |
| Pressure | The force per unit area, expressed in Pa, N/m², or psi. |
| Thickness | The distance between upper and lower surfaces of material measured under specified pressure. |
⚙️ Test Method and Procedure
The thickness of a highloft nonwoven fabric is determined by observing the linear distance that a movable plane is displaced from a parallel surface by the specimen while under a specified pressure. This test method is used for acceptance testing of commercial shipments.
Referenced documents include ASTM D123 (Terminology Relating to Textiles), D1776 (Practice for Conditioning Textiles for Testing), D1777 (Test Method for Measuring Thickness of Textile Materials), D2904 (Practice for Interlaboratory Testing), and D5729 (Test Method for Thickness of Nonwoven Fabrics). Proper conditioning per ASTM D1776 is essential for reproducible results.
💡 Tip: Ensure the specimen is conditioned in accordance with ASTM D1776 before testing to minimize variability and achieve accurate thickness measurements under the specified pressure.
📊 Significance and Use
This test method is widely used in the trade for acceptance testing. Thickness is one of the basic physical properties of highloft nonwoven fabrics. In case of a dispute arising from differences in reported test results, the purchaser and supplier should conduct comparative tests to determine any statistical bias between laboratories.
The standard recommends using a student’s t‑test with an acceptable probability level chosen by both parties. Test specimens should be homogeneous and randomly assigned to each laboratory for testing. Competent statistical assistance is advised for the investigation of bias.
| 🎯 Key Aspect | ⚡ Description |
|---|---|
| Purpose | Measure thickness of highloft nonwoven fabrics under specified pressure. |
| Units | SI units are the standard; inch‑pound units are approximate. |
| Dispute Resolution | Conduct comparative tests with statistical analysis (student’s t‑test). |
⚠️ Warning: This standard does not purport to address all safety concerns. Users are responsible for establishing appropriate safety and health practices and determining the applicability of regulatory limitations prior to use.
❓ Frequently Asked Questions
🔍 What is a highloft nonwoven fabric?
A highloft nonwoven fabric is a low‑density fiber network structure characterized by a high ratio of thickness to mass per unit area.
💡 How is thickness measured under specified pressure?
Thickness is determined by observing the linear distance a movable plane is displaced from a parallel surface by the specimen while under a specified pressure.
⚡ What units are used for pressure in this test method?
Pressure may be expressed in pascals (Pa), newtons per square metre (N/m²), or pound‑force per square inch (psi).
📌 How are disputes resolved in acceptance testing?
Disputes are resolved by conducting comparative tests using a student’s t‑test to determine statistical bias, with an acceptable probability level chosen by both parties.