ASTM C765-23

Standard Test Method for Low-Temperature Flexibility of Preformed Tape Sealants

SIGNIFICANCE AND USE
5.1 Preformed tape sealants are tacky, deformable solids that are used under compression between two substrates in a variety of sealing applications. This procedure is not intended to simulate an actual use condition, but it will give some indication of the flexibility and adhesion of a tape at low temperature. It can serve to differentiate between flexible tapes that can take some movement and those that tend to harden or embrittle on aging and crack or lose adhesion when flexed at low temperature. It will also aid in identifying sealants that have poor flexibility because they are overextended and contain a low level of binder as well as those sealants having binders that will embrittle at low temperature.
SCOPE
1.1 This test method covers a laboratory procedure for testing the low-temperature flexibility of preformed tape sealants.  
1.2 The values stated in SI units are to be regarded as the standard. The values 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: 30-Apr-2023
• ICS: 91.100.50 - Binders. Sealing materials
• Technical Committee: C24 - Building Seals and Sealants
• Drafting Committee: C24.20 - General Test Methods

Relations

• Refers: ASTM E145-19 - Standard Specification for Gravity-Convection and Forced-Ventilation Ovens
• Effective Date: 01-Mar-2019
• Refers: ASTM C717-19 - Standard Terminology of Building Seals and Sealants
• Effective Date: 01-Mar-2019
• Refers: ASTM C717-18 - Standard Terminology of Building Seals and Sealants
• Effective Date: 01-Mar-2018
• Refers: ASTM C717-17a - Standard Terminology of Building Seals and Sealants
• Effective Date: 01-Nov-2017
• Refers: ASTM C717-17 - Standard Terminology of Building Seals and Sealants
• Effective Date: 01-Jan-2017
• Refers: ASTM C717-16a - Standard Terminology of Building Seals and Sealants
• Effective Date: 15-Nov-2016
• Refers: ASTM C717-16 - Standard Terminology of Building Seals and Sealants
• Effective Date: 01-Sep-2016
• Refers: ASTM C717-14a - Standard Terminology of Building Seals and Sealants
• Effective Date: 01-May-2014
• Refers: ASTM C717-14 - Standard Terminology of Building Seals and Sealants
• Effective Date: 01-Feb-2014
• Refers: ASTM C717-13 - Standard Terminology of Building Seals and Sealants
• Effective Date: 01-Nov-2013
• Refers: ASTM C717-12b - Standard Terminology of Building Seals and Sealants
• Effective Date: 01-Dec-2012
• Refers: ASTM C717-12a - Standard Terminology of Building Seals and Sealants
• Effective Date: 01-May-2012
• Refers: ASTM C717-12 - Standard Terminology of Building Seals and Sealants
• Effective Date: 15-Jan-2012
• Refers: ASTM E145-94(2011) - Standard Specification for Gravity-Convection and Forced-Ventilation Ovens
• Effective Date: 01-Dec-2011
• Refers: ASTM C717-11a - Standard Terminology of Building Seals and Sealants
• Effective Date: 01-Mar-2011

Overview

ASTM C765-23: Standard Test Method for Low-Temperature Flexibility of Preformed Tape Sealants is an internationally recognized laboratory test method developed by ASTM. This standard establishes a procedure to evaluate the flexibility and adhesion of preformed tape sealants under low-temperature conditions. Preformed tape sealants are commonly used in various industries as tacky, deformable solids that are compressed between substrates to create airtight or watertight seals.

Testing low-temperature flexibility is crucial because sealants may harden, crack, or lose adhesion when exposed to cold environments over time. ASTM C765-23 helps distinguish between sealant tapes that remain flexible and those prone to embrittlement or adhesion loss at low temperatures.

Key Topics

• Purpose: Provides a standardized procedure to assess and differentiate the flexibility and adhesion of preformed tape sealants at low temperatures.
• Test Method Summary: Involves applying a sample of tape sealant to an aluminum panel, subjecting it to heat aging, and then rapidly bending it at cold temperatures to visually inspect for cracking or adhesion failure.
• Significance: The method does not simulate real-life use but offers a reliable indication of a sealant tape’s ability to withstand movement, aging, and environmental stress without losing flexibility or sticking power.
• Sealant Identification: Helps in identifying tapes that may be overextended, contain insufficient binder, or use binder materials susceptible to embrittlement at low temperatures.
• Reporting Requirements: Results include identification details of the sealant, percentage of adhesion loss, and descriptions of any observed cracking.

Applications

• Building and Construction: Ensuring preformed tape sealants used for window, door, or facade sealing perform reliably in cold climates.
• Transportation: Evaluating sealant performance for automotive, rail, and aerospace components exposed to low temperatures.
• Manufacturing Quality Control: Verifying product consistency and suitability for use in temperature-sensitive projects.
• Product Development: Supporting the design and formulation of new preformed tape sealant products that must endure thermal cycling and low-temperature exposure without mechanical failure.

By detecting products prone to embrittlement or adhesion loss, ASTM C765-23 helps manufacturers, contractors, and quality control professionals select appropriate tape sealants, improve production processes, and ensure compliance with industry requirements.

Related Standards

• ASTM C717: Terminology of Building Seals and Sealants - Defines key terms and concepts relevant to sealant products and test procedures.
• ASTM E145: Specification for Gravity-Convection and Forced-Ventilation Ovens - Specifies requirements for oven equipment used in specimen conditioning.
• International Standardization Principles: This standard aligns with global guidelines established by the World Trade Organization Technical Barriers to Trade (TBT) Committee, ensuring its applicability in international markets.

Practical Value

Implementing ASTM C765-23 provides clear benefits, including:

• Enhanced Product Reliability: Ensures only flexible, durable sealants are used in critical applications exposed to low temperatures.
• Improved Quality Assurance: Offers a repeatable, objective method to qualify products before deployment.
• Reduced Risk: Minimizes failures due to loss of adhesion or cracking, supporting safer, longer-lasting seals in the built environment and beyond.

Keywords: ASTM C765-23, low-temperature flexibility, preformed tape sealants, flexibility test, adhesion, embrittlement, building seals, cold climate performance, sealant testing standard.

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: C765 − 23
Standard Test Method for
Low-Temperature Flexibility of Preformed Tape Sealants
This standard is issued under the fixed designation C765; 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 freezer where the panel is quickly bent over a mandrel. The
specimen is examined for cracking and loss of adhesion.
1.1 This test method covers a laboratory procedure for
testing the low-temperature flexibility of preformed tape seal-
5. Significance and Use
ants.
5.1 Preformed tape sealants are tacky, deformable solids
1.2 The values stated in SI units are to be regarded as the
that are used under compression between two substrates in a
standard. The values in parentheses are for information only.
variety of sealing applications. This procedure is not intended
1.3 This standard does not purport to address all of the
to simulate an actual use condition, but it will give some
safety concerns, if any, associated with its use. It is the
indication of the flexibility and adhesion of a tape at low
responsibility of the user of this standard to establish appro-
temperature. It can serve to differentiate between flexible tapes
priate safety, health, and environmental practices and deter-
that can take some movement and those that tend to harden or
mine the applicability of regulatory limitations prior to use.
embrittle on aging and crack or lose adhesion when flexed at
1.4 This international standard was developed in accor-
low temperature. It will also aid in identifying sealants that
dance with internationally recognized principles on standard-
have poor flexibility because they are overextended and
ization established in the Decision on Principles for the
contain a low level of binder as well as those sealants having
Development of International Standards, Guides and Recom-
binders that will embrittle at low temperature.
mendations issued by the World Trade Organization Technical
6. Apparatus
Barriers to Trade (TBT) Committee.
6.1 Freezer Unit, capable of maintaining a temperature of
2. Referenced Documents
−23 °C 6 2 °C (−10 °F 6 3.6 °F).
2.1 ASTM Standards:
6.2 Aluminum Panel (mill finish), approximately 0.635 mm
C717 Terminology of Building Seals and Sealants
(0.025 in.) thick, 76 mm (3 in.) wide, and 152 mm (6 in.) long.
E145 Specification for Gravity-Convection and Forced-
6.3 Steel Mandrel, 25.4 mm (1 in.) in diameter, with
Ventilation Ovens
supporting holder or rack.
6.4 Vented Air Circulating Oven, that complies with Speci-
3. Terminology
fication E145 and is capable of maintaining a temperature of
3.1 Definitions—The definitions of the following terms used
70 °C 6 2 °C (158 °F 6 3.6 °F).
in this test method are found in Terminology C717: preformed
tape sealant, sealant.
7. Sampling
7.1 Samples to be tested shall be taken from a fresh roll of
4. Summary of Test Method
tape sealant after first removing and discarding approximately
4.1 The preformed tape sealant to be tested is applied to an
the first 0.61 m (2 ft) of the roll.
aluminum panel. The assembly is heat aged, then placed in the
8. Test Specimen
8.1 Prepare the test specimen as follows:
This test method is under the jurisdiction of ASTM Committee C24 on Building
8.1.1 Clean the 76 mm by 152 mm (3 in. by 6 in.) aluminum
Seals and Sealants and is the direct responsibility of Subcommittee C24.20 on
panel with methyl ethyl ketone or similar solvent.
General Test Methods.
8.1.2 Place a 102 mm (4 in.) length of tape in the center of
Current edition approved May 1, 2023. Publishe
...

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: C765 − 97 (Reapproved 2015) C765 − 23
Standard Test Method for
Low-Temperature Flexibility of Preformed Tape Sealants
This standard is issued under the fixed designation C765; 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 test method covers a laboratory procedure for testing the low-temperature flexibility of preformed tape sealants.
1.2 The values stated in SI units are to be regarded as the standard. The values 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 and healthsafety, 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:
C717 Terminology of Building Seals and Sealants
E145 Specification for Gravity-Convection and Forced-Ventilation Ovens
3. Terminology
3.1 Definitions—The definitions of the following terms used in this test method are found in Terminology C717: preformed tape
sealant, sealant.
4. Summary of Test Method
4.1 The preformed tape sealant to be tested is applied to an aluminum panel. The assembly is heat aged, then placed in the freezer
where the panel is quickly bent over a mandrel. The specimen is examined for cracking and loss of adhesion.
5. Significance and Use
5.1 Preformed tape sealants are tacky, deformable solids that are used under compression between two substrates in a variety of
sealing applications. This procedure is not intended to simulate an actual use condition, but it will give some indication of the
flexibility and adhesion of a tape at low temperature. It can serve to differentiate between flexible tapes that can take some
This test method is under the jurisdiction of ASTM Committee C24 on Building Seals and Sealants and is the direct responsibility of Subcommittee C24.20 on General
Test Methods.
Current edition approved June 1, 2015May 1, 2023. Published July 2015June 2023. Originally approved in 1973. Last previous edition approved in 20112015 as
C765–97(2011).C765 – 97 (2015). DOI: 10.1520/C0765-97R15.10.1520/C0765-23.
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.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C765 − 23
movement and those that tend to harden or embrittle on aging and crack or lose adhesion when flexed at low temperature. It will
also aid in identifying sealants that have poor flexibility because they are overextended and contain a low level of binder as well
as those sealants having binders that will embrittle at low temperature.
6. Apparatus
6.1 Freezer Unit, capable of maintaining a temperature of −23 6 2°C (−10 6 3.6°F).−23 °C 6 2 °C (−10 °F 6 3.6 °F).
6.2 Aluminum Panel (unpolished), (mill finish), approximately 0.635 mm (0.025 in.) thick, 76 mm (3 in.) wide, and 152 mm (6
in.) long.
6.3 Steel Mandrel, 25.4 mm (1 in.) in diameter, with supporting holder or rack.
6.4 Vente
...