ASTM D4895-04 - 1.2.2004
 
1. Scope

1.1 This specification covers dry-powder resins of polytetrafluoroethylene (PTFE) that have been prepared from dispersions of PTFE by manufacturing techniques that involve controlled coagulation of the dispersion. These resins are generally known as "fine-powder" resins or "coagulated-dispersion powder" resins. The conversion of these resins to finished products normally involves a process called "paste extrusion," and sometimes involves formative processes such as calendering. A volatile liquid is present as a processing aid during these formative stages of conversion, and is subsequently removed during the finishing stages of conversion. These PTFE resins are homopolymers of tetrafluoroethylene, or, in some cases, modified homopolymers containing not more than 1 % by weight of other fluoromonomers. The usual methods of processing thermoplastics generally are not applicable to these materials because of their viscoelastic properties. The materials covered herein do not include mixtures of PTFE with additives such as colors, fillers, or plasticizers; nor do they include reprocessed or reground resin or any fabricated articles because the properties of such materials have been irreversibly changed when they were fibrillated or sintered. The methods and properties included are those required to identify the various resins. An additional procedure is provided in the appendix for further characterization of the resins.

1.2 The values stated in SI units as detailed in IEEE/ASTM SI 10 are to be regarded as standard. The values given in brackets are for information only.

1.3 The following safety hazards caveat pertains only to the Specimen Preparation Section, Section 9, and the Test Methods Section, Section 10, of this specification: This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. See Warning note in for a specific hazards statement.

Note 1—Information in this specification is technically equivalent to related information in ISO 12086-1 and ISO 12086-2.

 
2. Referenced Documents

D638-22

Standard Test Method for Tensile Properties of Plastics

D792-20

Standard Test Methods for Density and Specific Gravity (Relative Density) of Plastics by Displacement

D883-26b

Standard Terminology Relating to Plastics (Includes all amendments and changes 8/24/2026).

D1708-26

Standard Test Method for Tensile Properties of Plastics by Use of Microtensile Specimens

D1895-24

Standard Test Methods for Apparent Density, Bulk Factor, and Pourability of Plastic Materials

D3892-15(2020)

Standard Practice for Packaging/Packing of Plastics

D4052-22

Standard Test Method for Density, Relative Density, and API Gravity of Liquids by Digital Density Meter

D4441-20(2025)

Standard Specification for Aqueous Dispersions of Polytetrafluoroethylene

D4591-22

Standard Test Method for Determining Temperatures and Heats of Transitions of Fluoropolymers by Differential Scanning Calorimetry

D4894-19(2024)

Standard Specification for Polytetrafluoroethylene (PTFE) Granular Molding and Ram Extrusion Materials

E11-24

Standard Specification for Woven Wire Test Sieve Cloth and Test Sieves

E29-22

Standard Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications

E177-26a

Standard Practice for Use of the Terms Precision and Bias in ASTM Test Methods (Includes all amendments and changes 5/14/2026).

IEEE/ASTM SI-10

Use of the International System of Units (SI): The Modern Metric System

D618-21

Standard Practice for Conditioning Plastics for Testing