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

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
1
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
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:
1
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. Published June 2023. Originally
the panel with its length paralleling that of the panel, leaving
approved in 1973. Last previous edition approved in 2015 as C765 – 97 (2015).
DOI: 10.1520/C0765-23.
the release paper in place on the preformed tape sealant.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
8.1.3 Use a hand roller to apply pressure along the length of
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
the tape sealant to ensure adhesion of the preformed tape
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. sealant to the panel.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

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C765 − 23
8.1.4 Remove the release paper from the test specimen. 11. Report
9. Conditioning 11.1 Report the f
...

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
1
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
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
1
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.
2
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
1

---------------------- Page: 1 ----------------------
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 Vented Air Circulating Oven, that complies with Specification E145 and is capable of maintaining a temperature of 70 6 2°C
(158 6 3.6°F).70 °C 6 2 °C (158 °F 6 3.6 °F).
7. Sampling
7.1 Samples to be tested shall be taken from a fresh roll of tape sealant after first removing and discarding approximately the first
0.61 m (2 ft) of the roll.
8. Test Specimen
8.1 Prepare the test specimen as follows:
8.1.1 Clean the 76-mm by 152-mm (3-in. by 6-in.)76 mm by 152 mm (3 in. by 6 in.) aluminum panel with methyl ethyl ketone
or similar solvent.
8.1.2 Place a 102-mm (4-in.)102 mm (4 in.) length of tape in the center of the panel with its length paralleling that of
...