ASTM D6338-98
(Classification)Standard Classification System for Highly Crosslinked Thermoplastic Vulcanizate (HCTPVs)
Standard Classification System for Highly Crosslinked Thermoplastic Vulcanizate (HCTPVs)
SCOPE
1.1 This classification system covers highly crosslinked themoplastic 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 (ᢗ %) 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 compostion with a lower level (< or = 95%) of crosslinking. the HCTPV polymer compostions 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.
1.3 As given in Practice E380, values in SI units are to be regarded as standard.
Note 1-There is no equivalent ISO standard.
1.4 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 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.
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Designation: D 6338 – 98
Standard Classification System for
Highly Crosslinked Thermoplastic Vulcanizates (HCTPVs)
This standard is issued under the fixed designation D 6338; 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 (e) indicates an editorial change since the last revision or reapproval.
INTRODUCTION
This classification system is intended as a means for the callout of materials for the fabrication of
parts or end-use items. It is not intended for material selection, which should be performed by those
with special expertise in the materials field. Material selection should be made after careful
consideration of: part performance and design; the environment in which the part must function; the
material properties covered and not covered by this classification system; the desired service lifetime
of the part; the fabrication process for the part; and material and fabrication costs.
1. Scope health practices and determine the applicability of regulatory
limitations prior to use.
1.1 This classification system covers highly crosslinked
thermoplastic vulcanizates (HCTPVs) for extrusion, molding
2. Referenced Documents
and other fabrication methods. HCTPVs are thermoplastic
2.1 ASTM Standards:
elastomers (TPEs) consisting of two or more polymer systems
D 395 Test Methods for Rubber Property—Compression
at least one of which is rubbery and highly (>95 %) crosslinked
Set
and at least one of which is thermoplastic, with each system
D 412 Test Methods for Vulcanized Rubber and Thermo-
having its own phase. The thermoplastic phase will tend to be
plastic Elastomers—Tension
continuous and the rubbery phase discontinuous. The high
D 471 Test Method for Rubber Property—Effect of Liq-
level of crosslinking and ultrafine particle size (ca 1 μm
uids
diameter) of the rubbery phase give rise to properties more
D 573 Test Method for Rubber—Deterioration in an Air
closely approaching those of conventional thermoset rubber,
Oven
when compared to the same thermoplastic/rubbery polymer
D 618 Practice for Conditioning Plastics and Electrical
composition with a lower level (#95 %) of crosslinking. The
Insulating Materials for Testing
HCTPV polymer compositions may contain fillers, reinforcing
D 638 Test Method for Tensile Properties of Plastics
agents, plasticizers, resins, antidegradants, colorants and other
D 883 Terminology Relating to Plastics
beneficial constituents. Recycled HCTPVs are not covered in
D 1434 Test Method for Determining Gas Permeability
this classification system.
Characteristics of Plastics and Sheeting
1.2 Included in this classification system are the properties
D 1566 Terminology Relating to Rubber
necessary to identify the respective compositions. For special-
D 1898 Practice for Sampling of Plastics
ized applications, other requirements may be needed to identify
D 2240 Test Method for Rubber Property—Durometer
specific characteristics.
Hardness
1.3 As given in Practice E 380, values in SI units are to be
D 3182 Practice for Rubber—Materials, Equipment, and
regarded as standard.
Procedures from Mixing Standard Compounds and Prepar-
NOTE 1—There is no equivalent ISO standard.
ing Standard Vulcanized Sheets
D 3892 Practice for Packaging/Packing of Plastics
1.4 The following safety hazards caveat pertains only to the
test methods portion, Section 12, of this classification system. D 4000 Classification System for Specifying Plastics Mate-
rials
This standard does not purport to address all of the safety
D 4019 Standard Test Method for Moisture in Plastics by
problems, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety and Coulometric Regeneration of Phosphorous Pentoxide
1 2
This specification is under the jurisdiction of ASTM Committee D-20 on Annual Book of ASTM Standards, Vol 09.01.
Plastics and is the direct responsibility of Subcommittee D 20.15 on Thermoplastic Annual Book of ASTM Standards, Vol 08.01.
Materials. Annual Book of ASTM Standards, Vol 15.09.
Current edition approved November 10, 1998. Published February 1999. Annual Book of ASTM Standards, Vol 08.02.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
D 6338
E 29 Practice for Using Significant Digits in Test Data
5 = 14 MPa, tensile strength, min, Test Method
Determine Conformance with Specifications
D 412 at 23°C,
E 380 Practice for Use of the International System of Units
6 = 6.0 MPa, tensile strength, min, Test
(SI) (the Modernized Metric System)
Method D 412 at 100°C,
4 = 80 %, weight change, max, Test Method
3. Terminology
D 471, IRM 903 oil, 24 h/121°C, and
3.1 Definitions—Except for the terms defined below, tech- 3 = 30 %, compression set, max, Test Method
nical terms pertaining to materials covered by this classifica- D 395, Procedure B, 22 h/100°C.
tion system are given in Terminologies D 883 and D 1566. The designation HCTPV 0100 would indicate no properties
3.2 Definitions of Terms Specific to This Standard: being specified.
3.2.1 dynamic vulcanization, n—the process of intimate 4.3.2 Although the values listed are necessary to include the
melt mixing a thermoplastic polymer with a suitably reactive range of properties available in existing materials, users should
rubbery polymer to generate a thermoplastic elastomer with a not infer that every possible combination of the properties
chemically crosslinked rubbery phase, resulting in properties exists or can be obtained.
closer to those of a thermoset rubber when compared to the
5. Suffixes
same uncrosslinked composition.
5.1 Necessary requirements for superseding or supplement-
3.2.2 thermoplastic elastomer (TPE), n—a diverse family of
ing the property-table or cell-table requirements shall be
rubberlike materials that, unlike conventional vulcanized rub-
specified with suffixes. The first suffix letter indicates the
bers, can be reprocessed and recycled like thermoplastic
special requirements needed; the second letter indicates the test
materials.
method or conditions, or both, with a there-digit number
3.2.3 thermoplastic vulcanizate (TPV), n—a thermoplastic
indicating the specific requirements. Permissible suffixes are
elastomer with a chemically crosslinked rubbery phase, pro-
listed in Table 3 of Classification D 4000.
duced by the dynamic vulcanization.
5.1.1 Additional suffixes will be added to this specification
as test requirements and methods are developed or requested,
4. Classification
or both.
4.1 Highly crosslinked thermoplastic vulcanizates are clas-
sified into groups according to the rubbery polymer(s) present. 6. Basic Requirements
These groups are subclassified into classes and grades as
6.1 Basic requirements from property or cell tables are
shown in Table HCTPV.
always in effect, unless superseded by specific suffix require-
4.1.1 To illustrate this classification system: the designation
ments, which always take precedence.
HCTPV 0121 would indicate HCTPV = highly crosslinked
7. General Requirements
thermoplastic vulcanizate, 01 (group) = EPDM rubber >95 %
7.1 Material composition shall be uniform and shall con-
crosslinked, 2 (class) = medium hardness, and 1 (grade)
form to the requirements of this specification. The product
meeting the requirements in Table HCTPV.
form and color of the HCTPVs shall be mutually agreed to by
4.1.2 To enable the incorporation of special or future
the parties involved.
materials, the “Other” category (0) for group, class and grade
is given in Table HCTPV. Basic properties can be obtained
8. Detail Requirements
from Table A.
8.1 Test specimens and their preparation shall conform to
4.2 There is no distinction between reinforced and unrein-
Table HCTPV and Table A, and applicable suffix requirements.
forced highly crosslinked thermoplastic vulcanizates.
8.2 For purposes of determining conformance, all specified
4.3 A six-character designation shall show the specific
limits for a specification (line call out) based on this classifi-
requirements for the HCTPVs. This designation shall consist of
cation system are absolute limits, as defined in Practice E 29.
the letter A and five digits comprising the property require-
8.2.1 With the absolute method, an observed value or a
ments in the order they appear in Table A.
calculated value is not rounded, but is to be compared directly
4.3.1 The following is an example of this classification
wit
...
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