Active Standard ASTM D6338 | Developed by Subcommittee: D20.15
Book of Standards Volume: 08.03
Historical (view previous versions of standard)
1.1 This classification system covers highly crosslinked thermoplastic vulcanizates (HCTPVs) for extrusion, molding and other fabrication methods. HCTPVs are thermoplastic elastomers (TPEs) 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 HCTPVs are not covered in this classification system.
1.2 Included in this classification system are the properties necessary to identify the respective compositions. For specialized applications, other requirements may be needed to identify specific characteristics.
Note 1—There is no known ISO equivalent to this standard.
1.4 This standard is based on testing completed in accordance with ASTM standard test methods.
1.5 The following safety hazards caveat pertains only to the test methods portion, Section 12, of this classification system. This standard does not purport to address all of the safety problems, 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.
2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.
D395 Test Methods for Rubber Property--Compression Set
D412 Test Methods for Vulcanized Rubber and Thermoplastic Elastomers--Tension
D471 Test Method for Rubber Property--Effect of Liquids
D573 Test Method for Rubber--Deterioration 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 Property--Durometer Hardness
D3182 Practice for Rubber--Materials, 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 Number Code 83.080.20 (Thermoplastic materials)