ASTM D5948-05(2020)
(Specification)Standard Specification for Molding Compounds, Thermosetting
Standard Specification for Molding Compounds, Thermosetting
ABSTRACT
This specification covers the basic properties of thermoset molding plastic compounds and the test methods used to establish the properties. The plastic compounds shall be a resin, cellulose-filled or mineral/glass-filled phenolic, melamine, polyester, diallyl iso-phthalate, diallyl ortho-phthalate, silicone, or epoxy. Standard test specimens shall be in the as-received condition or shall be conditioned before testing by humidity, immersion, or temperature conditioning. The specimens shall undergo mechanical or physical qualification tests which shall conform to the following properties: compressive strength; dimensional stability; flexural strength; heat deflection temperature; heat resistance; impact strength; tensile strength; and water absorption. Electrical qualification tests shall be conducted; wherein, the specimens shall comply with the following requirements: arc resistance; dielectric breakdown; dielectric constant; dielectric strength; dissipation factor; surface resistance; comparative track index; volume resistance; and water extract conductance. Tests for combustion qualification shall also be performed to determine the flame resistance ignition time, burning time, flammability, and toxicity requirements. Batch acceptance tests shall be conducted as well to ensure the quality conformance of the specimens.
SIGNIFICANCE AND USE
4.1 This specification is a revision of STD MIL-M-14H, Specification for Molding Compound, Thermosetting, retaining the MIL-M-14H material designations and property requirements while conforming to ASTM form and style. It is intended for qualification and batch acceptance for materials used by government and industry, and is intended as a direct replacement for MIL-M-14H.
SCOPE
1.1 This specification covers the basic properties of thermoset molding compounds and the test methods used to establish the properties.
1.2 Classification—Molding thermosetting plastic compounds shall be of the following resins and are covered by the individual specification sheets (see 5.1 and Annex A1 – Annex A8).
Resin
Phenolic, cellulose filled
Phenolic, mineral/glass filled
Melamine
Polyester
Diallyl iso-phthalate
Diallyl ortho-phthalate
Silicone
Epoxy
Note 1: There is no known ISO equivalent to this standard.
1.3 Order of Precedence—In the event of a conflict between the text of this specification and the references cited in Section 2 (except for related specification sheets), the text of this specification takes precedence. Nothing in this specification, however, supersedes applicable laws and regulations unless a specific exemption has been obtained.
1.4 The values stated in SI units are to be considered standard.
1.5 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
Relations
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:D5948 −05 (Reapproved 2020)
Standard Specification for
Molding Compounds, Thermosetting
This standard is issued under the fixed designation D5948; 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope* 2. Referenced Documents
1.1 This specification covers the basic properties of thermo- 2.1 ASTM Standards:
set molding compounds and the test methods used to establish D149 Test Method for Dielectric Breakdown Voltage and
the properties. DielectricStrengthofSolidElectricalInsulatingMaterials
at Commercial Power Frequencies
1.2 Classification—Molding thermosetting plastic com-
D150 Test Methods forAC Loss Characteristics and Permit-
pounds shall be of the following resins and are covered by the
tivity (Dielectric Constant) of Solid Electrical Insulation
individual specification sheets (see 5.1 and AnnexA1 – Annex
D229 Test Methods for Rigid Sheet and Plate Materials
A8).
Used for Electrical Insulation
Resin
D256 Test Methods for Determining the Izod Pendulum
Phenolic, cellulose filled
Phenolic, mineral/glass filled Impact Resistance of Plastics
Melamine
D495 Test Method for High-Voltage, Low-Current, Dry Arc
Polyester
Resistance of Solid Electrical Insulation
Diallyl iso-phthalate
Diallyl ortho-phthalate D570 Test Method for Water Absorption of Plastics
Silicone
D618 Practice for Conditioning Plastics for Testing
Epoxy
D638 Test Method for Tensile Properties of Plastics
NOTE 1—There is no known ISO equivalent to this standard.
D648 Test Method for Deflection Temperature of Plastics
1.3 Order of Precedence—In the event of a conflict between Under Flexural Load in the Edgewise Position
the text of this specification and the references cited in Section D695 Test Method for Compressive Properties of Rigid
2 (except for related specification sheets), the text of this Plastics
D790 Test Methods for Flexural Properties of Unreinforced
specification takes precedence. Nothing in this specification,
however, supersedes applicable laws and regulations unless a and Reinforced Plastics and Electrical Insulating Materi-
als
specific exemption has been obtained.
D796 Practice for Compression Molding Test Specimens of
1.4 The values stated in SI units are to be considered
Phenolic Molding Compounds (Withdrawn 1992)
standard.
D883 Terminology Relating to Plastics
1.5 This international standard was developed in accor-
D1896 Practice for Transfer Molding Test Specimens of
dance with internationally recognized principles on standard-
Thermosetting Compounds
ization established in the Decision on Principles for the
D3419 Practice for In-Line Screw-Injection Molding Test
Development of International Standards, Guides and Recom-
Specimens From Thermosetting Compounds
mendations issued by the World Trade Organization Technical
D3636 Practice for Sampling and Judging Quality of Solid
Barriers to Trade (TBT) Committee.
Electrical Insulating Materials
1 2
This specification is under the jurisdiction of ASTM Committee D20 on For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Plastics and is the direct responsibility of Subcommittee D20.16 on Thermosetting contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Materials. Standards volume information, refer to the standard’s Document Summary page on
Current edition approved Dec. 1, 2020. Published December 2020. Originally the ASTM website.
approved in 1996. Last previous edition approved in 2012 as D5948 - 05 (2012). The last approved version of this historical standard is referenced on
DOI: 10.1520/D5948-05R20. 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
D5948−05 (2020)
TABLE 1 Sampling and Conditioning for Mechanical/Physical Qualification Tests
NOTE 1—A50 % retention of initial flexural strength is required.
NOTE 2—The side of a test specimen is that area formed by the chase of the mold.
NOTE 3—The face of the test specimen is that area formed by the top or bottom force plug.
NOTE 4—When specified.
Property to Be Tested- ASTM Test Modified Specimens, Form, and Number Conditioning Procedure
Unit of Value
Mechanical/Physical Method by Dimension Tested (see Section 6)
Compressive strength, end- D695 . 25.4 by 12.7 by 12.7 mm 5 E-48/50 + C-96 ⁄23 ⁄50 MPa (minimum average)
wise
Dimensional stability . 7.2.1 127 bar, 12.7 by 12.7 mm 5 C-96/23/50 Percent (maximum average)
Flexural strength D790 7.2.2 127 bar, 6.4 by 12.7 mm 5 E-48/50 + C-96 ⁄23 ⁄50 MPa (minimum average)
Heat deflection temperature D648 7.2.3 127 bar, 12.7 by 12.7 mm 3 A Degrees Celsius (minimum
average)
Heat resistance (1) D790 7.2.4 127 bar, 6.4 by 12.7 mm 5 E-1/at designated tempera- Degrees Celsius (minimum
ture test. Test at tempera- average) at temperature
ture
Impact strength
Side (2) D256 . As per Test Method D256 5 E-48/50 + C96 ⁄23 ⁄50 J/m notch (minimum average)
Face (3), (4) D256 . As per Test Method D256 5 E-48/50 + C96 ⁄23 ⁄50 J/m notch (minimum average)
Tensile strength D638 . As per Test Method D638 5 E-48/50 + C-96 ⁄23 ⁄50 MPa (minimum average)
Water absorption D570 7.2.5 51-mm disk, 3.2 mm thick 3 E-24/100 + des + D-48 ⁄50 Percent (maximum average)
D3638 Test Method for Comparative Tracking Index of quirements while conforming to ASTM form and style. It is
Electrical Insulating Materials intended for qualification and batch acceptance for materials
D4350 Test Method for Corrosivity Index of Plastics and used by government and industry, and is intended as a direct
Fillers replacement for MIL-M-14H.
D4697 Guide for Maintaining Test Methods in the User’s
Laboratory (Withdrawn 2009)
5. Requirements
E994 Guide for Calibration and Testing LaboratoryAccredi-
5.1 Specification Sheets—The individual item requirements
tation Systems General Requirements for Operation and
shall be as specified herein and in accordance with the
Recognition (Withdrawn 2003)
applicable specification sheet (see Annex A1 – Annex A8). In
E1224 GuideforCategorizingFieldsofCapabilityforLabo-
the event of any conflict between the requirements of this
ratory Accreditation Purposes (Withdrawn 2002)
specification and the material specification, the latter shall
2.2 Underwriters Laboratory Standard:
govern.
UL 94 Tests for Flammability of Plastic Materials for Parts
5.2 Qualification—Molding compounds furnished under
in Devices and Appliances
this specification shall be products which conform to the
2.3 Other Standard:
applicable material specification and quality assurance provi-
DDC AD 297457 Procedure for Determining Toxicity of
sions in this specification.
Synthetic Compounds
5.3 Material Safety Data Sheet (MSDS)—The user shall be
3. Terminology
provided with a material safety data sheet.
3.1 For definitions of technical terms pertaining to plastics
5.4 Uniformity—All molding compound of the same brand
used in this specification, refer to Terminology D883.
from one manufacturer shall be uniform in texture, in color,
3.2 Definitions of Terms Specific to This Standard:
and in the specified properties as determined by the batch-
3.2.1 batch—a homogeneous unit of finished molding com-
acceptance inspection specified in 8.3.
pound manufactured at one time.
5.5 PropertyValues—Standardspecimensofthecompounds
3.2.2 heat resistance—the elevated temperature at which a
shall conform to the property values shown in the individual
particular material retains a minimum of 50 % of its original
specification sheets for qualification (see 8.2) and batch accep-
flexural strength measured at 23°C.
tance (see 8.3).
4. Significance and Use
6. Conditioning
4.1 This specification is a revision of STD MIL-M-14H,
6.1 Standard test specimens shall be conditioned before
Specification for Molding Compound, Thermosetting, retain-
testing, as specified in Tables 1-4.
ing the MIL-M-14H material designations and property re-
6.1.1 Nomenclature—The following letters shall be used to
indicate the respective general conditioning procedures:
Available from Underwriters Laboratories (UL), Corporate Progress, 333
6.1.1.1 Condition A—As received; no special conditioning.
Pfingsten Rd., Northbrook, IL 60062.
6.1.1.2 Condition C—Humidity conditioning in accordance
Available from National Technical Information Service (NTIS), U.S. Depart-
ment of Commerce, 5285 Port Royal Rd., Springfield, VA 22161. with Practice D618.
D5948−05 (2020)
TABLE 2 Sampling and Conditioning for Electrical Qualification Tests
Property to Be Tested- ASTM Test Modified Specimens, Form, and Number Conditioning Procedure
Unit of Value
Mechanical/Physical Method by Dimension Tested (see Section 6)
Arc resistance D495 . 102-mm disk, 3.17 mm thick 3 A seconds (minimum average)
Dielectric breakdown:
Short-time test D149 7.2.6 102-mm disk, 12.7 mm thick 1 E-48/50 + C-96 ⁄23 ⁄50 kilovolt (minimum average)
Step-by-step test 3 E-48/50 + C-96 ⁄23 ⁄50
Short-time test 1 E-48/50 + D-48 ⁄50
Step-by-step test 3 E-48/50 + D-48 ⁄50
Dielectric constant:
At 1 kHz D150 . 51-mm disk, 3.2 mm thick 3 E-48/50 + des maximum average
3 E-48/50 + D-24 ⁄23
At 1 MHz 51-mm disk, 3.2 mm thick 3 E-48/50 + des
3 E-48/50 + D-24 ⁄23
Dielectric strength:
Short-time test D149 7.2.6 102-mm disk, 3.2 mm thick 3 E-48/50 + C-96 ⁄23 ⁄50 kV/mm (minimum
Step-by-step test 5 E-48/50 + C-96 ⁄23 ⁄50 average)
Short-time test 3 E-48/50 + D-48 ⁄50
Step-by-step test 5 E-48/50 + D-48 ⁄50
Dissipation factor:
At 1 kHz D150 . 51-mm disk, 3.2 mm thick 3 E-48/50 + des maximum average
3 E-48/50 + D-24 ⁄23
At 1 MHz 51-mm disk, 3.2 mm thick 3 E-48/50 + des
3 E-48/50 + D-24 ⁄23
Surface resistance . 7.2.7 102-mm disk, 3.2 mm thick 5 C-720/70/100 + dew megaohms (minimum individual)
Comparative track index D3638 7.2.8 51-mm disk, 3.2 mm thick 5 A volts
Volume resistance . 7.2.7 102-mm disk, 3.2 mm thick 5 C-720/70/100 + dew megaohms (minimum individual)
Water extract conductance D4350 . . . E-144/71 siemens per centimetre
TABLE 3 Sampling and Conditioning for Combustion Qualification Tests
Conditioning
Property to Be Tested- ASTM Test Modified Specimens, Form, Number
Procedure Unit of Value
Mechanical/Physical Method by and Dimension Tested
(see Section 6)
Flame resistance ignition time D229 7.2.9 127-mm bar, 12.7 by 5 A seconds (minimum average)
12.7 mm
Burning time seconds (maximum average)
Flammability UL 94 7.2.10 127-mm bar, 12.7-mm 5 A rating/thickness (1.6, 3.2, or
thickness 6.4 mm)
Toxicity when heated:
Carbon dioxide
Carbon monoxide
Ammonia
Aldehydes as HCHO
Cyanide and HCN — 7.2.11 127-mm bar, 12.7 by 4 A parts per million (maximum
12.7 mm average)
Oxide of nitrogen as NO2
Hydrogen chloride
TABLE 4 Sampling and Conditioning for Batch Acceptance Tests
NOTE 1—The side of a test specimen is that area formed by the chase of the mold.
Property to Be Tested- ASTM Test Modified Specimens, Form, Number Conditioning Procedure
Unit of Value
Mechanical/Physical Method by and Dimension Tested (see Section 6)
Arc resistance D495 . 102-mm disk, 3.2 mm 3 A seconds (minimum aver-
thick age)
Comparative track index D3638 7.2.8 51-mm disk, 3.17 mm 5 A volts
thick
Dielectric constant at 1 MHz D150 . 51-mm disk, 3.2 mm thick 3 E-48/50 + D-24 ⁄23 maximum average
Dissipation factor at 1 MHz D150 . 51-mm disk, 3.2 mm thick 3 E-48/50 + D-24 ⁄23 maximum average
maximum average
Dielectric strength, step-by-step D149 7.2.6 102-mm disk, 3.2 mm 5 E-48/50 + D-48 ⁄50 kV/mm (minimum average)
thick
Flexural strength D790 7.2.2 127-mm bar, 6.4 by 12.7 5 E-48/50 + C-96 ⁄23 ⁄50 mPa (minimum average)
mm
Impact strength, side (1) D256 . in accordance with Test 5 E-48/50 + C-96 ⁄23 ⁄50 J/m notch (minimum
Methods D256 average)
Water absorption D570 7.2.5 51-mm disk, 3.2 mm thick 3 E-24/100 + des + D-48 ⁄50 percent (maximum aver-
age)
Water extract conductance D4350 7.2.12. . E-144/71 siemens per centimetre
D5948−05 (2020)
6.1.1.3 Condition D—Immersion conditioning in distilled follows: 48 h in a circulating air oven at 125 6 5°C plus 24 h
water in accordance with Practice D618. at 23 6 1.1°C and 50 6 2 % relative humidity. At the
6.1.1.4 Condition E—Temperature conditioning in accor- completion of 10 cycles, measure the final length of the
dancewithPracticeD618;ConditionDesiccation–coolingover specimenstothenearest0.01mm.Thepercentagedimensional
silica gel or calcium chloride in a desiccator at 23°C for 16 to change is calculated to the nearest 0.1 % as follows:
20haftertemperatureconditioninginaccordancewithPractice
Dimensional change,% (1)
D618.
initial length 2 final length
~ !
6.2 Designation—Conditioning procedures shall be desig-
5 3100
initial length
nated as follows:
6.2.1 A capital letter indicating the general condition of the
The average percent dimensional change of the five speci-
specimen; that is, as-received, humidity, immersion, or tem-
mens shall be recorded.
perature conditioning.
7.2.2 Flexural Strength—Use Test Method D790 to deter-
6.2.2 A number indicating the duration of the conditioning
mine flexural strength. The span-depth ratio shall be 16:1, and
in hours.
the dimensions of the test bar shall be 127 by 12.7 by 6.4 mm.
6.2.3 A number indicating the conditioning temperature in
7.2.3 Heat-DeflectionTemperature—UseTestMethodD648
degrees Celsius.
to determine heat-deflection temperature. The specimens shall
6.2.4 Anumber indicating relative humidity, whenever rela-
be placed directly in the oil bath and not in air. The stress load
tive humidity is controlled.
shall be 1.82 MPa.
7.2.4 Heat Resistance—Condition the specimen for1hat
6.3 The numbers shall be separated from each other by slant
the designated temperature. After conditioning, the flexural
marks and from the capital letter by a dash. A sequence of
strength (see 7.2.2) shall be tested at the same temperature in
conditions shall be denoted by use of a plus sign ( + ) between
accordance with Test Method D790. When measured at the
successive conditions.
elevated test temperature, the molding compound shall meet
Examples:
the heat resistance requirement of retaining 50 % of the
Condition C-96/23/50: Humidity condition, 96 h at 23 ± 1.1°C and 50 ±
flexural strength value as determined at 23°C. The average
...
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