ASTM F1921/F1921M-12(2018)

Standard Test Methods for Hot Seal Strength (Hot Tack) of Thermoplastic Polymers and Blends Comprising the Sealing Surfaces of Flexible Webs

SIGNIFICANCE AND USE
5.1 In form-fill operations, sealed areas of packages are frequently subject to disruptive forces while still hot. If the hot seals have inadequate resistance to these forces, breakage can occur during the packaging process. These test methods measure hot seal strength and can be used to characterize and rank materials in their ability to perform in commercial applications where this quality is critical.
SCOPE
1.1 These two test methods cover laboratory measurement of the strength of heatseals formed between thermoplastic surfaces of flexible webs, immediately after a seal has been made and before it cools to ambient temperature (hot tack strength).  
1.2 These test methods are restricted to instrumented hot tack testing, requiring a testing machine that automatically heatseals a specimen and immediately determines strength of the hot seal at a precisely measured time after conclusion of the sealing cycle. An additional prerequisite is that the operator shall have no influence on the test after the sealing sequence has begun. These test methods do not cover non-instrumented manual procedures employing springs, levers, pulleys and weights, where test results can be influenced by operator technique.  
1.3 Two variations of the instrumented hot tack test are described in these test methods, differing primarily in two respects: (a) rate of grip separation during testing of the sealed specimen, and (b) whether the testing machine generates the cooling curve of the material under test, or instead makes a measurement of the maximum force observed following a set delay time. Both test methods may be used to test all materials within the scope of these test methods and within the range and capacity of the machine employed. They are described in Section 4.  
1.4 SI units are preferred and shall be used in referee decisions. Values stated herein in inch-pound units are to be regarded separately and may not be exact equivalents to SI units. Therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the 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. The operator of the equipment is to be aware of pinch points as the seal jaws come together to make a seal, hot surfaces of the jaws, and sharp instruments used to cut specimens. It is recommended that the operator review safety precautions from the equipment supplier.  
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: Historical
• Publication Date: 31-Dec-2017
• ICS: 83.120 - Reinforced plastics
• Technical Committee: F02 - Primary Barrier Packaging
• Drafting Committee: F02.20 - Physical Properties

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: F1921/F1921M − 12 (Reapproved 2018)
Standard Test Methods for
Hot Seal Strength (Hot Tack) of Thermoplastic Polymers and
1
Blends Comprising the Sealing Surfaces of Flexible Webs
This standard is issued under the fixed designation F1921/F1921M; 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 priate safety, health, and environmental practices and deter-
mine the applicability of regulatory limitations prior to use.
1.1 These two test methods cover laboratory measurement
The operator of the equipment is to be aware of pinch points as
of the strength of heatseals formed between thermoplastic
the seal jaws come together to make a seal, hot surfaces of the
surfaces of flexible webs, immediately after a seal has been
jaws, and sharp instruments used to cut specimens. It is
made and before it cools to ambient temperature (hot tack
recommended that the operator review safety precautions from
strength).
the equipment supplier.
1.2 These test methods are restricted to instrumented hot
1.6 This international standard was developed in accor-
tack testing, requiring a testing machine that automatically
dance with internationally recognized principles on standard-
heatseals a specimen and immediately determines strength of
ization established in the Decision on Principles for the
the hot seal at a precisely measured time after conclusion of the
Development of International Standards, Guides and Recom-
sealing cycle. An additional prerequisite is that the operator
mendations issued by the World Trade Organization Technical
shall have no influence on the test after the sealing sequence
Barriers to Trade (TBT) Committee.
has begun. These test methods do not cover non-instrumented
manual procedures employing springs, levers, pulleys and
2. Referenced Documents
weights, where test results can be influenced by operator
2
2.1 ASTM Standards:
technique.
D882 Test Method for Tensile Properties of Thin Plastic
1.3 Two variations of the instrumented hot tack test are
Sheeting
described in these test methods, differing primarily in two
E171 Practice for Conditioning and Testing Flexible Barrier
respects: (a) rate of grip separation during testing of the sealed
Packaging
specimen, and (b) whether the testing machine generates the
E691 Practice for Conducting an Interlaboratory Study to
cooling curve of the material under test, or instead makes a
Determine the Precision of a Test Method
measurement of the maximum force observed following a set
F88 Test Method for Seal Strength of Flexible Barrier
delay time. Both test methods may be used to test all materials
Materials
within the scope of these test methods and within the range and
F2029 Practices for Making Laboratory Heat Seals for
capacity of the machine employed. They are described in
Determination of Heat Sealability of Flexible Barrier
Section 4.
Materials as Measured by Seal Strength
1.4 SI units are preferred and shall be used in referee
decisions. Values stated herein in inch-pound units are to be 3. Terminology
regarded separately and may not be exact equivalents to SI
3.1 Definitions:
units. Therefore, each system shall be used independently of
3.1.1 adhesive failure, n—a failure mode in which the seal
the other. Combining values from the two systems may result
fails at the original interface between the surfaces being sealed.
in non-conformance with the standard.
3.1.2 breadth, n—temperature range over which peel force
1.5 This standard does not purport to address all of the
of a seal is (relatively) constant.
safety concerns, if any, associated with its use. It is the
3.1.3 burnthrough, n—a state or condition of a heatseal
responsibility of the user of this standard to establish appro-
characterized by melted holes and thermal distortion.
1
These test methods are under the jurisdiction of ASTM Committee F02 on
Primary Barrier Packaging and are the direct responsibility of subcommittee F02.20
2
on Physical Properties. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Jan. 1, 2018. Published February 2018. Originally contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
ɛ1
approved in 1998. Last previous edition approved in 2012 as F1921/F1921M–12 . Standards volume information, refer to the standard’s Document Summary page on
DOI: 10.1520/F1921-12R18. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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F1921/F1921M − 12 (2018)
3.1.3.1
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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.
´1
Designation: F1921/F1921M − 12 F1921/F1921M − 12 (Reapproved 2018)
Standard Test Methods for
Hot Seal Strength (Hot Tack) of Thermoplastic Polymers and
1
Blends Comprising the Sealing Surfaces of Flexible Webs
This standard is issued under the fixed designation F1921/F1921M; 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
ε NOTE—Designation was corrected editorially in October 2013.
1. Scope
1.1 These two test methods cover laboratory measurement of the strength of heatseals formed between thermoplastic surfaces
of flexible webs, immediately after a seal has been made and before it cools to ambient temperature (hot tack strength).
1.2 These test methods are restricted to instrumented hot tack testing, requiring a testing machine that automatically heatseals
a specimen and immediately determines strength of the hot seal at a precisely measured time after conclusion of the sealing cycle.
An additional prerequisite is that the operator shall have no influence on the test after the sealing sequence has begun. These test
methods do not cover non-instrumented manual procedures employing springs, levers, pulleys and weights, where test results can
be influenced by operator technique.
1.3 Two variations of the instrumented hot tack test are described in these test methods, differing primarily in two respects: (a)
rate of grip separation during testing of the sealed specimen, and (b) whether the testing machine generates the cooling curve of
the material under test, or instead makes a measurement of the maximum force observed following a set delay time. Both test
methods may be used to test all materials within the scope of these test methods and within the range and capacity of the machine
employed. They are described in Section 4.
1.4 SI units are preferred and shall be used in referee decisions. Values stated herein in inch-pound units are to be regarded
separately and may not be exact equivalents to SI units. Therefore, each system shall be used independently of the other.
Combining values from the two systems may result in non-conformance with the 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 safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use. The operator of the equipment is to be aware of pinch points as the seal jaws
come together to make a seal, hot surfaces of the jaws, and sharp instruments used to cut specimens. It is recommended that the
operator review safety precautions from the equipment supplier.
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.
2. Referenced Documents
2
2.1 ASTM Standards:
D882 Test Method for Tensile Properties of Thin Plastic Sheeting
E171 Practice for Conditioning and Testing Flexible Barrier Packaging
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
F88 Test Method for Seal Strength of Flexible Barrier Materials
F2029 Practices for Making Laboratory Heat Seals for Determination of Heat Sealability of Flexible Barrier Materials as
Measured by Seal Strength
1
These test methods are under the jurisdiction of ASTM Committee F02 on FlexiblePrimary Barrier Packaging and are the direct responsibility of subcommittee F02.20
on Physical Properties.
Current edition approved July 1, 2012Jan. 1, 2018. Published August 2012February 2018. Originally approved in 1998. Last previous edition approved in 20042012 as
ɛ1
F1921-98(2004).F1921/F1921M–12 . DOI: 10.1520/F1921-12E01.10.1520/F1921-12R18.
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

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