ASTM D4895-04
(Specification)Standard Specification for Polytetrafluoroethylene (PTFE) Resin Produced From Dispersion
Standard Specification for Polytetrafluoroethylene (PTFE) Resin Produced From Dispersion
ABSTRACT
This specification covers dry-powder resins of polytetrafluoroethylene (PTFE) resin produced from dispersion. PTFE mixtures with additives are not covered in this specification. This specification covers type I and type II PTFE. The resins shall be tested for bulk density, particle size, water content, melting peak temperature, tensile strength, elongation at break, standard specific gravity, extrusion pressure, thermal instability index, and stretching void index. Specimen preparation, testing, inspection, and packaging shall be in accordance to the procedures indicated in this specification.
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.
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: D4895 – 04
Standard Specification for
Polytetrafluoroethylene (PTFE) Resin Produced From
1
Dispersion
This standard is issued under the fixed designation D4895; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the Department of Defense.
1. Scope* and determine the applicability of regulatory limitations prior
2 to use. See Warning note in 9.1.1 for a specific hazards
1.1 This specification covers dry-powder resins of polytet-
statement.
rafluoroethylene (PTFE) that have been prepared from disper-
sions of PTFE by manufacturing techniques that involve
NOTE 1—Information in this specification is technically equivalent to
controlled coagulation of the dispersion. These resins are related information in ISO 12086-1 and ISO 12086-2.
generally known as “fine-powder” resins or “coagulated-
2. Referenced Documents
dispersion powder” resins. The conversion of these resins to
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finished products normally involves a process called “paste 2.1 ASTM Standards:
D618 Practice for Conditioning Plastics for Testing
extrusion,” and sometimes involves formative processes such
as calendering. A volatile liquid is present as a processing aid D638 Test Method for Tensile Properties of Plastics
D792 Test Methods for Density and Specific Gravity (Rela-
during these formative stages of conversion, and is subse-
quently removed during the finishing stages of conversion. tive Density) of Plastics by Displacement
D883 Terminology Relating to Plastics
These PTFE resins are homopolymers of tetrafluoroethylene,
or,insomecases,modifiedhomopolymerscontainingnotmore D1895 TestMethodsforApparentDensity,BulkFactor,and
Pourability of Plastic Materials
than 1 % by weight of other fluoromonomers. The usual
methods of processing thermoplastics generally are not appli- D3892 Practice for Packaging/Packing of Plastics
D4052 Test Method for Density, Relative Density, and API
cabletothesematerialsbecauseoftheirviscoelasticproperties.
The materials covered herein do not include mixtures of PTFE Gravity of Liquids by Digital Density Meter
D4441 Specification for Aqueous Dispersions of Polytet-
withadditivessuchascolors,fillers,orplasticizers;nordothey
include reprocessed or reground resin or any fabricated articles rafluoroethylene
because the properties of such materials have been irreversibly D4591 Test Method for Determining Temperatures and
Heats of Transitions of Fluoropolymers by Differential
changed when they were fibrillated or sintered. The methods
and properties included are those required to identify the Scanning Calorimetry
D4894 Specification for Polytetrafluoroethylene (PTFE)
various resins. An additional procedure is provided in the
appendix for further characterization of the resins. Granular Molding and Ram Extrusion Materials
E11 SpecificationforWovenWireTestSieveClothandTest
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 Sieves
E29 Practice for Using Significant Digits in Test Data to
parentheses are for information only.
1.3 The following safety hazards caveat pertains only to the Determine Conformance with Specifications
E177 Practice for Use of the Terms Precision and Bias in
SpecimenPreparationSection,Section9,andtheTestMethods
Section, Section 10, of this specification: This standard does ASTM Test Methods
IEEE/ASTM SI-10 Use of the International System of
not purport to address all of the safety concerns, if any,
associated with its use. It is the responsibility of the user of this Units (SI): The Modern Metric System
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2.2 ISO Standards:
standard to establish appropriate safety and health practices
ISO 12086-1 Plastics Fluoropolymer Dispersions and
1
This specification is under the jurisdiction of ASTM Committee D20 on
Plastics and is the direct responsibility of Subcommittee D20.15 on Thermoplastic
3
Materials. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Feb. 1, 2004. Published March 2004. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 1989. Last previous edition approved in 1998 as D4895 - 98. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/D4895-04. the ASTM website.
2 4
Specifications for other forms of polytetrafluoroethylene are found in Specifi- Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St.,
cations D4441 and D4894. 4th Floor, New York, NY 10036.
*A Summary of Changes section appears at the end of this standard.
Copyright © ASTM I
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