ASTM D6343-14(2018)

Standard Test Methods for Thin Thermally Conductive Solid Materials for Electrical Insulation and Dielectric Applications

SIGNIFICANCE AND USE
4.1 These test methods are useful to determine compliance of thermally conductive sheet electrical insulation with specification requirements established jointly by a producer and a user.  
4.2 These test methods have been found useful for quality assessment. Results of the test methods can be useful in apparatus design.
SCOPE
1.1 This standard is a compilation of test methods for evaluating properties of thermally conductive electrical insulation sheet materials to be used for dielectric applications.  
1.2 Such materials are thin, compliant sheets, typically produced by mixing thermally conductive particulate fillers with organic or silicone binders. For added physical strength these materials are often reinforced with a woven or nonwoven fabric or a dielectric film.  
1.3 These test methods apply to thermally conductive sheet material ranging from about 0.02 to 6-mm thickness.  
1.4 The values stated in SI units are to be regarded as standard.
Note 1: There is no IEC publication or ISO standard equivalent to this standard.  
1.5 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.  See also 18.1.2 and 19.1.2.  
1.6 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.

General Information

• Status: Published
• Publication Date: 31-Oct-2018
• ICS: 29.035.99 - Other insulating materials
• Technical Committee: D09 - Electrical and Electronic Insulating Materials
• Drafting Committee: D09.01 - Electrical Insulating Products

Relations

• Replaces: ASTM D6343-14 - Standard Test Methods for Thin Thermally Conductive Solid Materials for Electrical Insulation and Dielectric Applications
• Effective Date: 01-Nov-2018
• Refers: ASTM D1711-24 - Standard Terminology Relating to Electrical Insulation
• Effective Date: 01-Mar-2024
• Refers: ASTM D883-24 - Standard Terminology Relating to Plastics
• Effective Date: 01-Feb-2024
• Refers: ASTM D883-23 - Standard Terminology Relating to Plastics
• Effective Date: 01-Nov-2023
• Refers: ASTM D883-20 - Standard Terminology Relating to Plastics
• Effective Date: 01-Jan-2020
• Refers: ASTM D149-20 - Standard Test Method for Dielectric Breakdown Voltage and Dielectric Strength of Solid Electrical Insulating Materials at Commercial Power Frequencies
• Effective Date: 01-Jan-2020
• Refers: ASTM D883-19c - Standard Terminology Relating to Plastics
• Effective Date: 01-Aug-2019
• Refers: ASTM D883-19a - Standard Terminology Relating to Plastics
• Effective Date: 15-Apr-2019
• Refers: ASTM D883-19 - Standard Terminology Relating to Plastics
• Effective Date: 01-Feb-2019
• Refers: ASTM D883-18a - Standard Terminology Relating to Plastics
• Effective Date: 01-Dec-2018
• Refers: ASTM D883-18 - Standard Terminology Relating to Plastics
• Effective Date: 01-Nov-2018
• Refers: ASTM D5470-17 - Standard Test Method for Thermal Transmission Properties of Thermally Conductive Electrical Insulation Materials
• Effective Date: 01-Nov-2017
• Refers: ASTM D883-17 - Standard Terminology Relating to Plastics
• Effective Date: 15-Aug-2017
• Refers: ASTM D1000-17 - Standard Test Methods for Pressure-Sensitive Adhesive-Coated Tapes Used for Electrical and Electronic Applications
• Effective Date: 01-Jul-2017
• Refers: ASTM D1711-15 - Standard Terminology Relating to Electrical Insulation
• Effective Date: 01-Nov-2015

Overview

ASTM D6343-14(2018) - Standard Test Methods for Thin Thermally Conductive Solid Materials for Electrical Insulation and Dielectric Applications specifies a comprehensive set of test methods for evaluating the key properties of thin, thermally conductive, electrically insulating sheet materials. These materials, typically ranging from 0.02 to 6 mm in thickness, are crucial in applications where efficient heat transfer and reliable electrical insulation are required, such as in electrical and electronic equipment.

The standard is widely used by manufacturers, quality assurance professionals, and designers to ensure that thermally conductive electrical insulation meets agreed-upon specification requirements and to assist in apparatus design considerations.

Key Topics

• Material Composition: Addresses sheets made by combining thermally conductive fillers with organic or silicone binders. These sheets may also be reinforced with fabrics or films for added mechanical strength.
• Test Methods: Outlines standardized procedures for measuring:
  • Thickness accuracy (critical for performance calculations)
  • Adhesion strength, breaking strength, tensile properties, and tear resistance
  • Hardness (using Shore durometer), and specific gravity
  • Thermal impedance and apparent thermal conductivity
  • Dielectric properties (permittivity, dissipation factor)
  • Volume resistivity and dielectric breakdown voltage
• Conditioning: Provides guidance for specimen preparation and conditioning, typically at 23°C and 50% relative humidity, to ensure consistent and reliable test results.
• Significance and Use: Emphasizes the practical value of these test methods in verifying compliance with specifications, quality assessment, and supporting apparatus design.

Applications

Materials covered by ASTM D6343-14(2018) are essential for a range of electrical insulation and dielectric applications, particularly where thermal management is paramount. Typical uses include:

• Electrical and Electronic Equipment: Serving as thermal interface materials and insulating barriers in transformers, electric motors, circuit boards, and power supplies.
• Dielectric Applications: Ensuring safe electrical separation of components while facilitating heat dissipation.
• Quality Assurance: Supporting production quality control and product development testing for compliance with customer or regulatory requirements.
• Apparatus Design: Providing reliable data essential for engineers to design components that require both electrical insulation and effective thermal conductivity.

Industrial sectors that rely on these materials include electronics manufacturing, automotive, renewable energy systems, and telecommunications.

Related Standards

ASTM D6343-14(2018) references several other ASTM standards for specific test procedures and terminology, including:

• ASTM D149 - Dielectric Breakdown Voltage and Dielectric Strength of Solid Electrical Insulating Materials
• ASTM D1000 - Pressure-Sensitive Adhesive-Coated Tapes for Electrical and Electronic Applications
• ASTM D150 - AC Loss Characteristics and Permittivity (Dielectric Constant) of Solid Electrical Insulation
• ASTM D257 - DC Resistance or Conductance of Insulating Materials
• ASTM D2240 - Rubber Property-Durometer Hardness
• ASTM D5470 - Thermal Transmission Properties of Thermally Conductive Electrical Insulation Materials

Note: There is currently no IEC or ISO equivalent to ASTM D6343-14(2018).

Summary

ASTM D6343-14(2018) provides a consistent, internationally recognized framework for evaluating thin, thermally conductive electrical insulation materials. By standardizing material testing for critical properties like thermal conductivity, dielectric strength, and mechanical integrity, it helps manufacturers, users, and designers ensure product safety, quality, and performance in demanding electrical and dielectric applications.

Standards Content (Sample)

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.
Designation: D6343 − 14 (Reapproved 2018)
Standard Test Methods for
Thin Thermally Conductive Solid Materials for Electrical
Insulation and Dielectric Applications
This standard is issued under the fixed designation D6343; 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.
1. Scope* Dielectric Strength of Solid Electrical Insulating Materials
at Commercial Power Frequencies
1.1 This standard is a compilation of test methods for
D150 Test Methods forAC Loss Characteristics and Permit-
evaluating properties of thermally conductive electrical insu-
tivity (Dielectric Constant) of Solid Electrical Insulation
lation sheet materials to be used for dielectric applications.
D257 Test Methods for DC Resistance or Conductance of
1.2 Such materials are thin, compliant sheets, typically
Insulating Materials
produced by mixing thermally conductive particulate fillers
D374M Test Methods for Thickness of Solid Electrical
with organic or silicone binders. For added physical strength
Insulation (Metric) (Withdrawn 2016)
these materials are often reinforced with a woven or nonwoven
D412 Test Methods forVulcanized Rubber andThermoplas-
fabric or a dielectric film.
tic Elastomers—Tension
1.3 These test methods apply to thermally conductive sheet D624 Test Method for Tear Strength of Conventional Vul-
canized Rubber and Thermoplastic Elastomers
material ranging from about 0.02 to 6-mm thickness.
D792 Test Methods for Density and Specific Gravity (Rela-
1.4 The values stated in SI units are to be regarded as
tive Density) of Plastics by Displacement
standard.
D883 Terminology Relating to Plastics
NOTE 1—There is no IEC publication or ISO standard equivalent to this
D1000 Test Methods for Pressure-Sensitive Adhesive-
standard.
Coated Tapes Used for Electrical and Electronic Applica-
1.5 This standard does not purport to address all of the
tions
safety concerns, if any, associated with its use. It is the
D1458 Test Methods for Fully Cured Silicone Rubber-
responsibility of the user of this standard to establish appro-
Coated Glass Fabric and Tapes for Electrical Insulation
priate safety, health, and environmental practices and deter-
D1711 Terminology Relating to Electrical Insulation
mine the applicability of regulatory limitations prior to use.
D2240 Test Method for Rubber Property—Durometer Hard-
See also 18.1.2 and 19.1.2.
ness
1.6 This international standard was developed in accor-
D5470 Test Method for Thermal Transmission Properties of
dance with internationally recognized principles on standard-
Thermally Conductive Electrical Insulation Materials
ization established in the Decision on Principles for the
D6054 Practice for Conditioning Electrical Insulating Mate-
Development of International Standards, Guides and Recom-
rials for Testing (Withdrawn 2012)
mendations issued by the World Trade Organization Technical
3. Terminology
Barriers to Trade (TBT) Committee.
3.1 Definitions:
2. Referenced Documents
3.1.1 For definitions of terms used in these test methods and
associated with electrical and electronic insulating materials,
2.1 ASTM Standards:
use Terminology D1711.
D149 Test Method for Dielectric Breakdown Voltage and
3.1.2 For definitions of terms used in these test methods and
associated with plastics, use Terminology D883.
These test methods are under the jurisdiction of ASTM Committee D09 on
3.2 Definitions of Terms Specific to This Standard:
Electrical and Electronic Insulating Materials and are the direct responsibility of
3.2.1 apparent thermal conductivity, n—thetimerateofheat
Subcommittee D09.01 on Electrical Insulating Products.
flow, under steady conditions, through unit area, per unit
Current edition approved Nov. 1, 2018. Published November 2018. Originally
approved in 1998. Last previous edition approved in 2014 as D6343 – 14. DOI: temperature gradient in the direction perpendicular to the area,
10.1520/D6343-14R18.
for a nonhomogeneous material.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on The last approved version of this historical standard is referenced on
the ASTM website. www.astm.org.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D6343 − 14 (2018)
the buyer and seller to agree on other conditions of pressure, anvil and
3.2.1.1 See 16.1 for a discussion of the terms thermal
presser foot geometry, and the dwell time to be used.
conductivity and apparent thermal conductivity. To avoid
confusion, these test methods use apparent thermal conductiv- 8.3 Report—Report the thickness in millimetres as the
ity for measurements of homogeneous and nonhomogeneous average of the five measurements.
materials.
9. Adhesion Strength
4. Significance and Use
9.1 Significance and Use—Materials covered by this test
methodareoptionallycoatedwithapressuresensitiveadhesive
4.1 These test methods are useful to determine compliance
on one or both sides. In some cases performance in a particular
of thermally conductive sheet electrical insulation with speci-
application can be affected by the adhesion strength.
fication requirements established jointly by a producer and a
user.
9.2 Procedure—Test three specimens of 25-mm width in
accordance with Test Methods D1000, except clean the steel
4.2 These test methods have been found useful for quality
panel with isopropyl alcohol.
assessment. Results of the test methods can be useful in
apparatus design.
9.3 Calculation—From the three specimens, calculate the
average adhesion strength.
5. Specimen Preparation
9.4 Report—Report the average adhesion strength in new-
5.1 From a sample of sufficient size, prepare test specimens
tons per metre of width.
of the dimensions and of the quantity to meet the requirements
for each test procedure.
10. Breaking Strength
10.1 Significance and Use—In some cases, breaking
6. Conditioning
strength is a significant limitation on methods of applying
6.1 Unless otherwise specified, condition specimens in ac-
tapes.Hence,measurementsofthetensileforcetheyareableto
cordancewithProcedureAofPracticeD6054.Performalltests
withstand are potentially important data.
on specimens that are in equilibrium with the conditions of
10.2 Procedure:
Procedure A of Practice D6054. Make the tests in a chamber
10.2.1 Prepare three specimens at least 500 mm long and
maintained at 23 6 2°C and 50 6 5 % relative humidity.
25 mm wide. If the material contains reinforcing fibers, cut the
6.2 When required by a test procedure, condition specimens
testspecimensuchthatthemachinedirectionreinforcingfibers
in accordance with Procedure D of Practice D6054, except that
are parallel to the long axis of the specimen. In the case of
either distilled or deionized water are permitted to be used. In
materials narrower than 25 mm, test the full width as received.
such cases, remove the specimens from the water into air
10.2.2 Test the breaking strength in accordance with Test
maintained at 23 6 2°C and 50 6 5 % relative humidity,
Methods D1458.
remove surface water with a paper towel, and begin testing
10.3 Calculation—From the test measurements on the three
within 30 s.
specimens, calculate the average breaking strength.
7. Precision and Bias
10.4 Report—Report the average breaking strength in new-
7.1 No evaluation of precision or bias has been established tons per metre of width.
forthetestmethodshereinastheyrelatetothesethinthermally
11. Tensile Strength and Elongation
conductive materials. For general guidance only, it is suitable
to make reference to Precision and Bias statements in the
11.1 Significance and Use—Tensile test results with these
referenced test methods as listed in Section 2. materials will vary with specimen geometry and conditions of
testing. Hence, these tensile measurements are not always
8. Thickness
reliable indicators of usefulness in a particular application.
8.1 Significance and Use—The accurate determination of Tensile properties of glass-fiber-reinforced materials vary with
the ratio of the glass-fiber thickness to the total thickness.
thickness is essential for design purposes for both thermal
Measurements of tensile properties vary with the direction of
conduction and electrical insulation. Thickness enters into the
the glass fibers with respect to the direction in which the
calculation of thermal, electrical, and tensile properties.
specimen is cut.
8.2 Procedure:
11.2 Procedure:
8.2.1 Make thickness measurements on specimens in accor-
11.2.1 Prepare three specimens in accordance with Test
dance with Test Methods D374M, Method H. This test method
Methods D412, using Die C.
uses a micrometer which applies a pressure of 26 6 4 kPa on
11.2.2 If the material contains reinforcing fibers, cut the test
the specimen, using a 6.25-mm diameter presser foot.
specimensuchthatanyreinforcingfibersareat45 610°tothe
8.2.2 Clean the surfaces where the measurements are to be
long axis of the specimen.
made. Take five randomly spaced measurements to cover the
11.2.3 In accordance with Test Methods D412, measure the
length and width of the specimen. Take measurements at least
tensile breaking strength and tensile elongation at a jaw
6 mm from the edges of the specimen.
separation rate of 500 mm/min (20 in./min).
NOTE 2—At the compressive loads of this test method, some materials
will undergo compression or compression deflection. It is important for 11.3 Calculation:
D6343 − 14 (2018)
11.3.1 Calculatethetensilestrengthinkilopascals,usingthe 14.3 Calculation—Calculate the tear strength for each
initial thickness and width for each specimen. Calculate the specimen by dividing the maximum force by the specimen
average tensile strength from the three test measurements. thickness. Calculate the average from the three test measure-
11.3.2 Similarly, calculate each elongation at break as a ments.
percentage of the initial jaw separation. Calculate the average
14.4 Report—Report the average tear strength in newtons
from the three test measurements.
per millimetre.
11.4 Report—Report the average tensile strength in kilopas-
15. Thermal Impedance
cals and the average elongation in percent.
15.1 Significance and Use—Thermal impedance measure-
12. Hardness ments are affected by applied pressure, thickness, any surface
irregularities, and uniformity of heat flow. Since the results
12.1 Significance and Use—This test method is empirical
obtained by these test methods represent thermal characteris-
and intended for control purposes only.
tics of a material under a specific set of conditions, it is not
12.2 Procedure:
appropriate to use these results to predict performance in an
12.2.1 Prepare a sufficient number of specimens to form a
application where conditio
...