ASTM D4708-24

Standard Practice for Preparation of Uniform Free Films of Organic Coatings

SIGNIFICANCE AND USE
5.1 Free films are required for conducting tests to evaluate physical and mechanical properties such as tensile and elongation (Test Methods D2370), moisture vapor permeability (Test Methods D1653 and E96/E96M), microbiological activity resistance (Test Method D5590), and other physical properties of organic coatings where the substrate may interfere with the determination.
SCOPE
1.1 This practice covers the preparation of free films of organic coatings for use in determining the physical properties of the coatings.  
1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.  
1.3 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.  
1.4 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: 14-Jan-2024
• ICS: 25.220.60 - Organic coatings
• Technical Committee: D01 - Paint and Related Coatings, Materials, and Applications
• Drafting Committee: D01.23 - Physical Properties of Applied Paint Films

Relations

• Replaces: ASTM D4708-19 - Standard Practice for Preparation of Uniform Free Films of Organic Coatings
• Effective Date: 15-Jan-2024
• Refers: ASTM E96/E96M-24 - Standard Test Methods for Gravimetric Determination of Water Vapor Transmission Rate of Materials
• Effective Date: 01-Mar-2024
• Refers: ASTM E96/E96M-23 - Standard Test Methods for Gravimetric Determination of Water Vapor Transmission Rate of Materials
• Effective Date: 15-Nov-2023
• Referred By: ASTM C1841-23 - Standard Specification for Interior Radiation Control Coating (IRCC) for Building Applications
• Effective Date: 15-Jan-2024
• Referred By: ASTM D5590-17(2021) - Standard Test Method for Determining the Resistance of Paint Films and Related Coatings to Fungal Defacement by Accelerated Four-Week Agar Plate Assay
• Effective Date: 15-Jan-2024
• Referred By: ASTM E1795-20a - Standard Specification for Non-Reinforced Liquid Coating Encapsulation Products for Leaded Paint in Buildings
• Effective Date: 15-Jan-2024
• Referred By: ASTM D1653-13(2021) - Standard Test Methods for Water Vapor Transmission of Organic Coating Films
• Effective Date: 15-Jan-2024
• Referred By: ASTM D2370-16(2021) - Standard Test Method for Tensile Properties of Organic Coatings
• Effective Date: 15-Jan-2024
• Referred By: ASTM D6093-97(2022) - Standard Test Method for Percent Volume Nonvolatile Matter in Clear or Pigmented Coatings Using a Helium Gas Pycnometer
• Effective Date: 15-Jan-2024

Overview

ASTM D4708-24: Standard Practice for Preparation of Uniform Free Films of Organic Coatings establishes procedures for preparing free films of organic coatings. Free films are essential for evaluating the physical and mechanical properties of coatings without interference from a substrate. This internationally recognized standard supports consistent testing conditions, facilitating accurate measurement of properties such as tensile strength, elongation, moisture vapor transmission, and resistance to microbial activity.

Key Topics

• Free Films Preparation
  The standard details methods for producing uniform, substrate-free films from paints, lacquers, varnishes, and related organic coatings. Common release substrates include FEP sheets, silicone-coated paper, glass plates, and polytetrafluoroethylene (PTFE) sheets.

• Testing Physical Properties
  Free films produced using this method are suitable for a range of laboratory tests:

  • Tensile and Elongation (ASTM D2370)
  • Moisture Vapor Permeability (ASTM D1653, E96/E96M)
  • Microbiological Resistance (ASTM D5590) These tests help characterize coating materials where direct application to a test panel would yield skewed results due to substrate interaction.

• Uniform Thickness and Quality Control
  Guidelines are provided for applying coatings and ensuring the resulting films are uniform in thickness, defect-free, and suitable for subsequent analysis. The film is dried under controlled temperature and humidity or baked as specified.

• Equipment and Materials
  Essential apparatus includes film applicators, micrometers for thickness measurement, appropriate substrate materials, surfactants or release agents, and precision cutting tools.

• Safety and Regulatory Considerations
  Users are responsible for addressing safety, health, and environmental issues, assessing regulatory compliance according to local and international guidelines.

Applications

• Laboratory Testing of Coatings
  Organizations in the coatings industry use ASTM D4708-24 to produce standardized films for research and development, quality control, and product certification. This is critical for manufacturing reliable paints, varnishes, and specialty coatings.

• Comparative Material Evaluation
  By eliminating substrate influence, the standard enables direct comparison of different coating formulations under identical test scenarios, supporting product improvement and innovation.

• Compliance and Standardization
  Adoption of ASTM D4708-24 ensures that testing protocols align with global standards, enabling manufacturers to demonstrate compliance with international requirements for coating performance.

Related Standards

• ASTM D16: Terminology for Paint, Related Coatings, Materials, and Applications
• ASTM D823: Practices for Producing Films of Uniform Thickness of Paint, Coatings, and Related Products on Test Panels
• ASTM D1005: Test Method for Measurement of Dry-Film Thickness of Organic Coatings Using Micrometers
• ASTM D1653: Test Methods for Water Vapor Transmission of Organic Coating Films
• ASTM D2370: Test Method for Tensile Properties of Organic Coatings
• ASTM D5590: Test Method for Determining the Resistance of Paint Films and Related Coatings to Fungal Defacement
• ASTM E96/E96M: Test Methods for Gravimetric Determination of Water Vapor Transmission Rate of Materials

Practical Value

Implementing ASTM D4708-24 enables manufacturers and laboratories to accurately assess the intrinsic properties of organic coatings, leading to better product development, performance assurance, and alignment with regulatory and customer requirements. Consistent preparation of free films, as described in this standard, is fundamental for credible coating analysis in industrial and scientific 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: D4708 − 24
Standard Practice for
Preparation of Uniform Free Films of Organic Coatings
This standard is issued under the fixed designation D4708; 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* Accelerated Four-Week Agar Plate Assay
E96/E96M Test Methods for Gravimetric Determination of
1.1 This practice covers the preparation of free films of
Water Vapor Transmission Rate of Materials
organic coatings for use in determining the physical properties
of the coatings.
3. Terminology
1.2 The values stated in SI units are to be regarded as the
3.1 Definitions:
standard. The values given in parentheses are for information
3.1.1 For definitions of terms used in this standard, refer to
only.
Terminology D16.
1.3 This standard does not purport to address all of the
4. Summary of Test Method
safety concerns, if any, associated with its use. It is the
4.1 Free films are prepared by depositing a uniform wet
responsibility of the user of this standard to establish appro-
coating of the test material on a release substrate. The applied
priate safety, health, and environmental practices and deter-
films are dried or baked, cut into appropriate size for the
mine the applicability of regulatory limitations prior to use.
intended physical property test, and then stripped from the
1.4 This international standard was developed in accor-
release substrate.
dance with internationally recognized principles on standard-
ization established in the Decision on Principles for the
5. Significance and Use
Development of International Standards, Guides and Recom-
5.1 Free films are required for conducting tests to evaluate
mendations issued by the World Trade Organization Technical
physical and mechanical properties such as tensile and elon-
Barriers to Trade (TBT) Committee.
gation (Test Methods D2370), moisture vapor permeability
(Test Methods D1653 and E96/E96M), microbiological activ-
2. Referenced Documents
ity resistance (Test Method D5590), and other physical prop-
2.1 ASTM Standards:
erties of organic coatings where the substrate may interfere
D16 Terminology for Paint, Related Coatings, Materials, and
with the determination.
Applications
D823 Practices for Producing Films of Uniform Thickness
6. Apparatus and Materials
of Paint, Coatings and Related Products on Test Panels
6.1 Equipment, for applying films of uniform thickness as
D1005 Test Method for Measurement of Dry-Film Thick-
described in Practices D823.
ness of Organic Coatings Using Micrometers
6.2 Micrometer Film Thickness Gauge, as described in Test
D1653 Test Methods for Water Vapor Transmission of Or-
Method D1005.
ganic Coating Films
D2370 Test Method for Tensile Properties of Organic Coat-
6.3 Release Substrates, any film releasing flat substrate
ings
which does not alter film properties and which allows the
D5590 Test Method for Determining the Resistance of Paint
casting of coating films with a uniform thickness. Examples of
Films and Related Coatings to Fungal Defacement by
suitable substrates are as follows:
6.3.1 Sheet of FEP, (polyhexafluoropropylene).
6.3.2 Sheet of Silicone Coated Paper, preferably 125 μm
This practice is under the jurisdiction of ASTM Committee D01 on Paint and
(5 mil) thick.
Related Coatings, Materials, and Applications and is the direct responsibility of
6.3.3 Glass Plates, coated with halosilane compound.
Subcommittee D01.23 on Physical Properties of Applied Paint Films.
6.3.4 Steel Panel, wrapped with polyvinyl fluoride film,
Current edition approved Jan. 15, 2024. Published January 2024. Originally
preferably 25 μm to 50 μm (1 mils to 2 mils) thick.
approved in 1987. Last previous edition approved in 2019 as D4708 – 19. DOI:
10.1520/D4708-24.
6.3.5 Flat Panel, coated with release agent.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
6.3.6 Polytetrafluoroethylene Sheet, (with or without glass
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
fiber reinforcement) wiped with diluted surfactant solution as
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. needed.
*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
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...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D4708 − 19 D4708 − 24
Standard Practice for
Preparation of Uniform Free Films of Organic Coatings
This standard is issued under the fixed designation D4708; 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*
1.1 This practice covers the preparation of free films of organic coatings for use in determining the physical properties of the
coatings.
1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.3 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.
1.4 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
2.1 ASTM Standards:
D16 Terminology for Paint, Related Coatings, Materials, and Applications
D823 Practices for Producing Films of Uniform Thickness of Paint, Coatings and Related Products on Test Panels
D1005 Test Method for Measurement of Dry-Film Thickness of Organic Coatings Using Micrometers
D1653 Test Methods for Water Vapor Transmission of Organic Coating Films
D2370 Test Method for Tensile Properties of Organic Coatings
D5590 Test Method for Determining the Resistance of Paint Films and Related Coatings to Fungal Defacement by Accelerated
Four-Week Agar Plate Assay
E96/E96M Test Methods for Gravimetric Determination of Water Vapor Transmission Rate of Materials
3. Terminology
3.1 Definitions:
3.1.1 For definitions of terms used in this standard, refer to Terminology D16.
4. Summary of Test Method
4.1 Free films are prepared by depositing a uniform wet coating of the test material on a release substrate. The applied films are
dried or baked, cut into appropriate size for the intended physical property test, and then stripped from the release substrate.
This practice is under the jurisdiction of ASTM Committee D01 on Paint and Related Coatings, Materials, and Applications and is the direct responsibility of
Subcommittee D01.23 on Physical Properties of Applied Paint Films.
Current edition approved March 1, 2019Jan. 15, 2024. Published August 2019January 2024. Originally approved in 1987. Last previous edition approved in 20122019
as D4708 – 12.D4708 – 19. DOI: 10.1520/D4708-19.10.1520/D4708-24.
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 ASTM website.
*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
D4708 − 24
5. Significance and Use
5.1 Free films are required for conducting tests to evaluate physical and mechanical properties such as tensile and elongation (Test
Methods D2370), moisture vapor permeability (Test Methods D1653 and E96/E96M), microbiological activity resistance (Test
Method D5590), and other physical properties of organic coatings where the substrate may interfere with the determination.
6. Apparatus and Materials
6.1 Equipment, for applying films of uniform thickness as described in Practices D823.
6.2 Micrometer Film Thickness Gage,Gauge, as described in Test Method D1005.
6.3 Release Substrates, any film releasing flat substrate which does not alter film properties and which allows the casting of
coating films with a uniform thickness. Examples of suitable substrates are as follows:
6.3.1 Sheet of FEP—FEP, (polyhexafluoropropylene).
6.3.2 Sheet of Silicone Coated Paper, preferably 125-μm (5-mil)125 μm (5 mil) thick.
6.3.3 Glass Plates, coated with halosilane compound.
6.3.4 Steel Panel—Panel, Wrappedwrapped with polyvinyl fluoride film, preferably 25 to 50–μm (125 μm to 50 μm (1 mils to 2
mils) thick.
6.3.5 Flat Panel—Panel, Coatedcoated with release agent.
6.3.6 Polytetrafluoroethylene Sheet, (with or without glass fiber reinforcement) wiped with diluted surfactant solution as needed.
6.3.7 Polyethylene Film, preferably 50 μm in thickness, wrapped around a glass sheet.
6.4 Surfactant Solution—Solution, Diluteddiluted surfactant solution. Fluorinated surfactants are preferred due to their high
efficiency.
NOTE 1—Solution comprising 0.50.5 % t
...