ASTM D4441

ASTM D4441 – Standard Specification for Aqueous Dispersions of Polytetrafluoroethylene

Description:

Abstract

This specification establishes the properties and test methods for aqueous dispersions of polytetrafluoroethylene (PTFE) resins, and is used to determine if a shipment, lot, or container of PTFE dispersions is suitable for its intended use. These resins are homopolymers of tetrafluoroethylene, or in some cases modified homopolymers containing not more than 1% by weight of other fluoromonomers, and the dispersions are usually stabilized by one or more surfactants. Other non-PTFE materials may be present in total at 5% or less by weight for special purposes. This specification is for virgin materials only, and does not cover PTFE copolymers or filled dispersions, and recycled materials as they are not appropriate for dispersions. Materials shall be appropriately sampled for testing on the following: pH value; solid and surfactant content by gravimetric weight loss; solid content by hydrometer; test for coagulated polymer; specific gravity; and melting characteristics.

Scope

1.1 This specification covers aqueous dispersions of polytetrafluoroethylene (PTFE) resins. These resins are homopolymers of tetrafluoroethylene, or in some cases modified homopolymers containing not more than 1 % by weight of other fluoromonomers.

1.1.1 The dispersion is usually stabilized by one or more surfactants. Other non-PTFE materials may be present in total at 5 % or less by weight for special purposes.

1.1.2 This specification is for virgin material only and does not address recycled material as it is not appropriate for dispersions.

1.2 This specification is used to determine if a shipment, lot, or container of PTFE dispersion is suitable for its intended use. It covers only aqueous dispersions of polytetrafluoroethylene. It does not cover PTFE copolymers or filled dispersions. This specification includes test methods for both aqueous dispersion and the PTFE in the dispersion.

Note 1: Uses for the PTFE dispersion covered by this specification include, but are not limited to, casting of their films, impregnation of mechanical packings and other materials, surface coatings on various substrates, combined impregnation and coating of fibrous materials, and co-coagulation with other materials for subsequent processing into films, sheets, rods, and tubes.

Note 2: Information in this specification is technically equivalent to related information in ISO 20568-1 and ISO 20568-2.

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