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D2116-16 – Standard Test Method Technical Guide
📋 Scope and Classification
ASTM D2116 – 16 (Reapproved 2021) covers melt processable molding and extrusion materials of FEP resin. These FEP resins are specifically defined as copolymers of tetrafluoroethylene (TFE) and hexafluoropropylene (HFP), or modified FEP resins containing no more than 2 % by weight of other fluoromonomers. The specification explicitly excludes recycled FEP materials.
Materials are classified into four types based on their melt flow rate (MFR), as established in Section 4.1. These resins are typically supplied in pellet form.
| 📐 Type Classification | ⚡ Melt Flow Rate (g/10 min) |
|---|---|
| Type I | 2.1 – 4.9 |
| Type II | 5.0 – 9.9 |
| Type III | 10.0 – 18.0 |
| Type IV | 19.0 – 25.0 |
Although this specification and ISO 12086‑1 / ISO 12086‑2 differ in approach or detail, data obtained using either set of methods is technically equivalent.
🔬 Key Properties and Standard Test Methods
The specification mandates specific ASTM test methods for evaluating the properties of FEP materials. These standardized methods ensure consistency across different production lots and laboratory facilities. The following table outlines the primary test methods referenced in the standard.
| 🟦 Property | 📏 Test Method |
|---|---|
| Melt Flow Rate (MFR) | Test Method D1238 |
| Tensile Properties | Test Method D638 or D1708 |
| Density and Specific Gravity | Test Methods D792 |
| AC Loss and Permittivity | Test Methods D150 |
| Melting Temperature (DSC) | Test Method D4591 |
| Conditioning for Testing | Practice D618 |
| Packaging and Packing | Practice D3892 |
The values stated in SI units, as detailed in IEEE/ASTM SI-10, are regarded as the standard. The standard also adopts definitions from Terminology D883 and abbreviated terms from Terminology D1600.
The test methods portion of this specification (Section 11) does not purport to address all safety concerns. It is the responsibility of the user to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
🏭 Terminology and Lot Definition
ASTM D2116 defines a lot as “one production run or a uniform blend of two or more production runs.” This standard incorporates the general definitions provided in Terminology D883 and the abbreviated terms from D1600. A key requirement for acceptance testing is adherence to the specified conditioning procedures outlined in Practice D618. This international standard was developed in accordance with the WTO Technical Barriers to Trade (TBT) principles and has been approved for use by agencies of the U.S. Department of Defense.
❓ Frequently Asked Questions
🔍 What specific copolymers are classified by ASTM D2116?
The standard covers FEP resins that are copolymers of tetrafluoroethylene (TFE) and hexafluoropropylene (HFP), or modified FEP resins containing no more than 2 % by weight of other fluoromonomers.
💡 How are the four types of FEP resin distinguished?
The types (I, II, III, and IV) are classified strictly by their melt flow rate (MFR), measured in g/10 min as determined by Test Method D1238.
⚡ Which unit system is the primary standard for this specification?
The values stated in SI units, as detailed in IEEE/ASTM SI-10, are regarded as the standard. Values given in parentheses (Imperial units) are for information only.
📌 Does this standard cover recycled FEP materials?
No. The scope in Section 1.1 explicitly states that this specification does not cover recycled FEP materials.