Plastics film and sheeting — Determination of impact resistance by the free-falling dart method — Part 2: Instrumented puncture test

This document specifies a test method for the determination of puncture impact properties of a plastic film using instruments for measuring force and deflection. It is applicable if a force-deflection or force-time diagram, recorded at nominally constant striker velocity, is required for detailed characterization of the impact behaviour. This test method is also required when a small number of test specimens are available, and the staircase method described in the ISO 7765-1 cannot be applied. The test method is applicable to films of up to 1 mm thickness and makes it possible to compare impact-penetration forces, biaxial deformabilities and energy-absorption capacities of films. Also, the transition region between brittle and tough behaviour of the film under the conditions of testing can be determined by varying the temperature or the penetration velocity or the relative humidity[1].

Film et feuille de plastiques — Détermination de la résistance au choc par la méthode par chute libre de projectile — Partie 2: Essai avec appareil de perforation

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Published
Publication Date
19-May-2022
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4060 - Close of voting
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14-Oct-2021
Completion Date
13-Oct-2021
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ISO 7765-2:2022 - Plastics film and sheeting — Determination of impact resistance by the free-falling dart method — Part 2: Instrumented puncture test Released:5/20/2022
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INTERNATIONAL ISO
STANDARD 7765-2
Second edition
2022-05
Plastics film and sheeting —
Determination of impact resistance by
the free-falling dart method —
Part 2:
Instrumented puncture test
Film et feuille de plastiques — Détermination de la résistance au choc
par la méthode par chute libre de projectile —
Partie 2: Essai avec appareil de perforation
Reference number
ISO 7765-2:2022(E)
© ISO 2022
---------------------- Page: 1 ----------------------
ISO 7765-2:2022(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2022

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on

the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below

or ISO’s member body in the country of the requester.
ISO copyright office
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CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
© ISO 2022 – All rights reserved
---------------------- Page: 2 ----------------------
ISO 7765-2:2022(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

Introduction .................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ..................................................................................................................................................................................... 1

3 Terms and definitions .................................................................................................................................................................................... 1

4 Principle ........................................................................................................................................................................................................................ 4

5 Apparatus .................................................................................................................................................................................................................... 5

5.1 General ........................................................................................................................................................................................................... 5

5.2 Test device .................................................................................................................................................................................................. 5

5.2.1 General ........................................................................................................................................................................................ 5

5.2.2 Energy carrier ....................................................................................................................................................................... 6

5.2.3 Striker .......................................................................................................................................................................................... 7

5.2.4 Clamping device .................................................................................................................................................................. 7

5.3 Instrument for measuring force and deflection ....................................................................................................... 9

5.3.1 General ........................................................................................................................................................................................ 9

5.3.2 Force measurement sensor ....................................................................................................................................... 9

5.3.3 Deflection measurement system ......................................................................................................................... 9

5.4 Thickness gauge .................................................................................................................................................................................... 9

6 Test specimens ....................................................................................................................................................................................................... 9

6.1 Sampling and preparation of test specimens .............................................................................................................. 9

6.2 Number of test specimens ......................................................................................................................................................... 10

6.3 Conditioning of test specimens ............................................................................................................................................. 10

7 Procedure .................................................................................................................................................................................................................10

7.1 Test atmosphere ................................................................................................................................................................................. 10

7.2 Measuring the thickness ............................................................................................................................................................. 10

7.3 Clamping the test specimen ..................................................................................................................................................... 10

7.4 Impact-penetration test ............................................................................................................................................................... 10

8 Calculation and expression of results ........................................................................................................................................11

9 Precision ....................................................................................................................................................................................................................12

10 Test report ...............................................................................................................................................................................................................12

Annex A (informative) General remarks ......................................................................................................................................................14

Bibliography .............................................................................................................................................................................................................................15

iii
© ISO 2022 – All rights reserved
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ISO 7765-2:2022(E)
Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards

bodies (ISO member bodies). The work of preparing International Standards is normally carried out

through ISO technical committees. Each member body interested in a subject for which a technical

committee has been established has the right to be represented on that committee. International

organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.

ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of

electrotechnical standardization.

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the

different types of ISO documents should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www.iso.org/patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to

the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see

www.iso.org/iso/foreword.html.

This document was prepared by Technical Committee ISO/TC 61, Plastics, Subcommittee SC 11,

Products.

This second edition cancels and replaces the first edition (ISO 7765-2:1994), which has been technically

revised.
The main changes are as follows:
— impact failure definition has been added (3.7);
— the list of clamping devices and techniques has been updated (5.2.4);
— the force measurement (5.3) has been aligned with the ISO 6603-2 method;
— the calculation clause (Clause 8) has been aligned with the ISO 6603-2 method;
— test report requirements (Clause 10) have been improved.
A list of all parts in the ISO 7765 series can be found on the ISO website.

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at www.iso.org/members.html.
© ISO 2022 – All rights reserved
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ISO 7765-2:2022(E)
Introduction

The impact-penetration test described in the ISO 7765 series is used for the assessment of plastic films

and thin sheets (hereinafter referred to as films) under an impact stress applied at right angles to the

plane of the film.

ISO 7765-1 can be used if it is sufficient to characterize the impact behaviour of the film by an impact

failure energy. This document is used if a force-deformation or a force-time diagram, recorded at

practically constant velocity of the striker, is necessary for characterization of the impact behaviour.

Annex A of is for information only.
© ISO 2022 – All rights reserved
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INTERNATIONAL STANDARD ISO 7765-2:2022(E)
Plastics film and sheeting — Determination of impact
resistance by the free-falling dart method —
Part 2:
Instrumented puncture test
1 Scope

This document specifies a test method for the determination of puncture impact properties of a plastic

film using instruments for measuring force and deflection. It is applicable if a force-deflection or force-

time diagram, recorded at nominally constant striker velocity, is required for detailed characterization

of the impact behaviour. This test method is also required when a small number of test specimens are

available, and the staircase method described in the ISO 7765-1 cannot be applied.

The test method is applicable to films of up to 1 mm thickness and makes it possible to compare

impact-penetration forces, biaxial deformabilities and energy-absorption capacities of films. Also, the

transition region between brittle and tough behaviour of the film under the conditions of testing can be

[1]

determined by varying the temperature or the penetration velocity or the relative humidity .

2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements of this document. For dated references, only the edition cited applies. For

undated references, the latest edition of the referenced document (including any amendments) applies.

ISO 291, Plastics — Standard atmospheres for conditioning and testing

ISO 4593, Plastics — Film and sheeting — Determination of thickness by mechanical scanning

3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.

ISO and IEC maintain terminology databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
peak force
maximum force exerted by the striker in the direction of impact during the test
Note 1 to entry: See Figures 1 to 3.
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ISO 7765-2:2022(E)
3.2
deformation at peak force

deformation in the direction of impact at the centre of the test specimen corresponding to the peak

force (3.1)

Note 1 to entry: For materials exhibiting a peak-force plateau, the deformation is taken at the centre of the

plateau (see Figure 1).
3.3
energy to peak force

area under the force-deformation curve bounded by the origin, the peak force and the deformation at

peak force (3.2)
Note 1 to entry: See Figures 1 to 3.
3.4
total penetration energy

area under the force-deformation curve bounded by the origin, the peak force (3.1) and the deformation

at peak force (3.2)
Note 1 to entry: See Figures 1 to 3.

Note 2 to entry: If the force-deformation diagram as measured during the test is influenced strongly by dynamic

resonance effects, a mean curve may be used to obtain the values of the parameters defined in 3.1 to 3.4. This,

however, is seldom the case when plastic film is tested

Note 3 to entry: In contrast to the instrumented puncture test applied to test specimens made of brittle plastic

(see ISO 6603-2), the force-deformation diagram of this test applied to film and sheeting frequently shows a clear

point of first failure (failure point) indicated by a sharp drop in the force. If this is the case, and if the interested

parties agree to use this point as a characteristic criterion, the following additional definitions may be used.

3.5
failure force

force exerted by the striker in the direction of impact, measured at the failure point

Note 1 to entry: See Figures 1 and 2.
3.6
failure deformation

deformation in the direction of impact at the centre of the test specimen, measured at the failure, point

Note 1 to entry: See Figures 1 and 2.
3.6.1
failure energy

area under the force deformation curve bounded by the origin, the failure force (3.5) and the failure

deformation (3.6)
Note 1 to entry: See Figures 1 and 2.

Note 2 to entry: When comparing films of slightly different thicknesses, it is advisable to relate F , F , W and

M F M

W to the thickness d of the specimen. Though the normalized values F /d, F /d, W /d and W /d do not allow a

F M F M F

physically exact comparison between film specimens of different materials, the thickness dependence of these

normalized values is negligible for similar materials (those with the same amount of crystallinity and the same

orientation) provided the thicknesses do not differ by more than a factor of 1,5.

© ISO 2022 – All rights reserved
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ISO 7765-2:2022(E)
3.7
impact failure

mechanical behaviour of the material under test which may be either one of the following types:

a) ductile. If a clear failure point is available and parts agree, the ductile behaviour can be described

in terms of “Very tough” (see Figure 1 as example) and “Tough” (see Figure 2 as example)

b) brittle
Key
Y force
X deformation
Figure 1 — Force-deformation diagram for very tough materials (schematic)
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ISO 7765-2:2022(E)
Key
Y force
X deformation
Figure 2 — Force-deformation diagram for tough materials (schematic)
Key
Y force
X deformation
Figure 3 — Force-deformation diagram for brittle materials (schematic)
4 Principle

The test specimen is penetrated normal to its plane by a striker at a nominally uniform velocity. The

resulting force-deformation or force-time diagram is electronically recorded. The test specimen is

firmly clamped during the test.
© ISO 2022 – All rights reserved
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ISO 7765-2:2022(E)

The force-deformation diagram obtained in these tests shows several features of the material's

behaviour under impact. For example, the fracture may be “brittle”, “ductile” – “tough” or “very tough”

– or characterized by initial damage or by crack initiation and propagation. In addition, dynamic effects

may be present, such as load-cell/indenter resonance, specimen resonance and initial contact/inertia

peaks (see Figures 1 to 3).

In all cases, care shall be exercised in analysing these features because the operative mechanism and

the trains of inference are not yet fully established, and are the subject of continuing research.

The test results are comparable only if the conditions for preparation of specimens, their thickness

and surfaces, and the test conditions are identical. Comprehensive evaluation of the reaction to impact

stress requires that the determinations are made as functions of deformation rate and temperature for

different material variables, such as crystallinity and moisture content.
5 Apparatus
5.1 General

The apparatus consists of a mechanical test device for applying the test force, instruments for

measuring the force and the deformation produced, and a thickness gauge.
5.2 Test device
5.2.1 General

The essential components of the test device are the energy carrier (normally a falling mass, but a

pneumatically, hydraulically or spring-driven mass or a pendulum impact-testing device may also be

used), the striker, and the clamping device consisting of the test specimen support and the clamping

ring (see Figures 4 and 5).

The apparatus shall permit the test specimen to be punctured at the centre at a nominally constant

velocity, perpendicular to the specimen surface. The force exerted on the test specimen in the direction

of impact and the deformation of the specimen in the direction of impact shall be measurable or

derivable (see Figure 4). Equipment suitable for this are falling dart machines, pendulums long enough

for the penetration path to be regarded as approximately straight, or high-speed tensile-testing

machines with suitable attachments.
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ISO 7765-2:2022(E)
Key
1 test specimen
2 hemispherical striker, diameter D
3 load cell (preferred position)
4 shaft
5 clamping ri
...

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