ASTM D6338 - 17

    Standard Classification System for Highly Crosslinked Thermoplastic Vulcanizates (HCTPV) Based on ASTM Standard Test Methods

    Active Standard ASTM D6338 | Developed by Subcommittee: D20.15

    Book of Standards Volume: 08.03


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    1. Scope

    1.1 This classification system covers highly crosslinked thermoplastic vulcanizates (HCTPV) for extrusion, molding and other fabrication methods. Highly crosslinked thermoplastic vulcanizates (HCTPV) are thermoplastic elastomers (TPE) consisting of two or more polymer systems at least one of which is rubbery and highly (>95 %) crosslinked and at least one of which is thermoplastic, with each system having its own phase. The thermoplastic phase will tend to be continuous and the rubbery phase discontinuous. The high level of crosslinking and ultrafine particle size (ca 1 μm diameter) of the rubbery phase give rise to properties more closely approaching those of conventional thermoset rubber, when compared to the same thermoplastic/rubbery polymer composition with a lower level (95 %) of crosslinking. The HCTPV polymer compositions may contain fillers, reinforcing agents, plasticizers, resins, antidegradants, colorants and other beneficial constituents. Recycled HCTPV are not covered in this classification system.

    1.2 The properties included in this standard are those required to identify the compositions covered. Other requirements necessary to identify particular characteristics important to specialized applications are to be specified by using suffixes as given in Section 5.

    1.3 This classification system and subsequent line callout (specification) are intended to provide a means of calling out plastic materials used in the fabrication of end items or parts. It is not intended for the selection of materials. Material selection can be made by those having expertise in the plastic field only after careful consideration of the design and the performance required of the part, the environment to which it will be exposed, the fabrication process to be employed, the costs involved, and the inherent properties of the material other than those covered by this standard.

    1.4 As given in IEEE/ASTM SI-10, values in SI units are to be regarded as standard.

    Note 1: There is no known ISO equivalent to this standard.

    1.5 This standard is based on testing completed in accordance with ASTM standard test methods.

    1.6 The following safety hazards caveat pertains only to the test methods portion, Section 11, of this classification system. 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, health and environmental practices and determine the applicability of regulatory limitations prior to use.

    1.7 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.


    2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.

    ASTM Standards

    D395 Test Methods for Rubber PropertyCompression Set

    D412 Test Methods for Vulcanized Rubber and Thermoplastic ElastomersTension

    D471 Test Method for Rubber PropertyEffect of Liquids

    D573 Test Method for RubberDeterioration in an Air Oven

    D618 Practice for Conditioning Plastics for Testing

    D638 Test Method for Tensile Properties of Plastics

    D883 Terminology Relating to Plastics

    D1434 Test Method for Determining Gas Permeability Characteristics of Plastic Film and Sheeting

    D1566 Terminology Relating to Rubber

    D2240 Test Method for Rubber PropertyDurometer Hardness

    D3182 Practice for RubberMaterials, Equipment, and Procedures for Mixing Standard Compounds and Preparing Standard Vulcanized Sheets

    D3892 Practice for Packaging/Packing of Plastics

    D4000 Classification System for Specifying Plastic Materials

    D6869 Test Method for Coulometric and Volumetric Determination of Moisture in Plastics Using the Karl Fischer Reaction (the Reaction of Iodine with Water)

    E29 Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications


    ICS Code

    ICS Number Code 83.080.20 (Thermoplastic materials)

    UNSPSC Code

    UNSPSC Code 13102000(Thermoplastic plastics)


    Referencing This Standard
    Link Here
    Link to Active (This link will always route to the current Active version of the standard.)

    DOI: 10.1520/D6338-17

    Citation Format

    ASTM D6338-17, Standard Classification System for Highly Crosslinked Thermoplastic Vulcanizates (HCTPV) Based on ASTM Standard Test Methods, ASTM International, West Conshohocken, PA, 2017, www.astm.org

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