prEN ISO 22970

SLOVENSKI STANDARD
oSIST prEN ISO 22970:2020
01-september-2020
Barve in laki - Preskusna metoda za vrednotenje oprijema elastičnih lepil na

premazih s preskušanjem luščenja, trdnosti luščenja ter natezne in strižne trdnosti

Paints and varnishes - Test method for evaluation of adhesion of elastic adhesives on

coatings by peel test, peel strength test and tensile lap-shear strength test with additional

Beschichtungsstoffe - Prüfverfahren zur Beurteilung der Haftfestigkeit von elastischen

Klebstoffen auf Beschichtungen durch Prüfen der Schälhaftung, Schälfestigkeit und

Zugscherfestigkeit mit zusätzlicher Beanspruchung durch Kondenswasserprüfung oder

Peintures et vernis - Évaluation de l'adhérence des adhésifs élastiques sur les produits

de peinture en examinant l'adhérence, la résistance au pelage et la résistance à la

traction et le cisaillement en combinaison avec l'exposition à l'eau de condensation ou

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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

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

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

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

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

4 Principle ........................................................................................................................................................................................................................ 2

4.1 Adhesive strength test method A — Peel adhesion ................................................................................................ 2

4.2 Adhesive strength test method B — Peel strength .................................................................................................. 2

4.3 Adhesive strength test method C — Tensile lap-shear strength .................................................................. 3

4.4 Conduction of the test ....................................................................................................................................................................... 3

5 Apparatus and test media ........................................................................................................................................................................... 3

5.1 Adhesive strength test method A — Peel adhesion ................................................................................................ 3

5.2 Adhesive strength test method B — Peel strength .................................................................................................. 4

5.3 Adhesive strength test method C — Tensile lap-shear strength .................................................................. 4

5.4 Exposure method 1 — Condensation atmosphere with constant humidity ..................................... 5

5.5 Exposure method 2 — Cataplasm storage ...................................................................................................................... 5

6 Sequence of adhesive strength tests A, B and C .................................................................................................................... 5

7 Preparation of specimens ........................................................................................................................................................................... 6

7.1 Preparation of test panels ............................................................................................................................................................. 6

7.2 Adhesive strength test method A — Peel adhesion ................................................................................................ 6

7.2.1 Bead shape ............................................................................................................................................................................ 6

7.2.2 Application of the adhesive bead ....................................................................................................................... 7

7.3 Adhesive strength test method B — Peel strength ...............................................................................................10

7.4 Adhesive strength test method C — Tensile lap-shear strength ...............................................................11

8 Curing and exposure of specimens with applied adhesive ....................................................................................14

8.1 Curing ...........................................................................................................................................................................................................14

8.2 Reference value determination ..............................................................................................................................................15

8.3 Exposure methods ............................................................................................................................................................................15

8.3.1 Exposure method 1 — Condensation atmosphere with constant humidity .............15

8.3.2 Exposure method 2 — Cataplasm storage .............................................................................................15

9 Test procedure .....................................................................................................................................................................................................15

9.1 Adhesive strength test method A — Peel adhesion .............................................................................................15

9.2 Adhesive strength test method B — Peel strength ...............................................................................................17

9.3 Adhesive strength test method C — Tensile lap-shear strength ...............................................................18

10 Expression of results .....................................................................................................................................................................................18

10.1 Adhesive strength test method A — Peel adhesion .............................................................................................18

10.2 Adhesive strength test method B — Peel strength ...............................................................................................19

10.3 Adhesive strength test method C — Tensile lap-shear strength ...............................................................20

11 Designation .............................................................................................................................................................................................................20

12 Precision ....................................................................................................................................................................................................................21

13 Test report ................................................................................................................................................................................................................21

Bibliography .............................................................................................................................................................................................................................23

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

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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

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

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

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This document was prepared by Technical Committee ISO/TC 35, Paints and varnishes, Subcommittee

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

This document specifies three methods for testing the peel adhesion, peel strength and tensile lap-

shear strength in order to evaluate the adhesive bond as well as the type, location and structure of

failures of elastic adhesives on coatings. These methods are used, for example, for testing the assembly

with respect to the bond of panes or built-on parts, such as plastic covers, spoilers, instrument panel

covers, headlights, with coatings for automobile construction. The two methods of climatic exposure of

NOTE The peel strength test (method B) for rigid car body construction adhesives is described in ISO 8510-2.

The tensile lap-shear strength test (method C) for rigid car body construction adhesives is described in EN 1465.

Testing of rigid car body construction adhesives is generally conducted on small joint thicknesses, i.e. <1 mm.

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 3270, Paints and varnishes and their raw materials — Temperatures and humidities for conditioning

ISO 6270-2, Paints and varnishes — Determination of resistance to humidity — Part 2: Condensation (in-

ISO 17872, Paints and varnishes — Guidelines for the introduction of scribe marks through coatings on

DIN 55997, Solvents for paints and varnishes — Deionized water — Requirements and methods of test

For the purposes of this document, the terms and definitions given in ISO 4618 and the following apply.

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

non-metallic substance capable of joining materials by surface bonding (adhesion), where the bond

stressing in shear of an overlap specimen between rigid adherends (3.2) by applying to the adherends a

tensile force which is parallel to the bond area and to the major axis of the specimen

failure of an adhesive bond within the body of the adhesive (3.1), i.e. not at the interface

failure of an adhesive bond in such a way that the separation appears to be at the adhesive/adherend

It describes the peel adhesion test of adhesives on coatings. This method is suitable where a qualitative,

i.e. visual, evaluation of an adhesive’s behaviour is sufficient or when testing large and voluminous parts.

The adhesive is applied to the test panel in form of a (round or triangular) bead, dried and peeled off the

coating using a cutter knife and, if required, pliers. This is followed by a visual evaluation of the failure

It describes the adhesive strength testing of adhesives by determination of the peel force. This method

enhances the range of results obtained using method A by additional quantitative measurement values

The adhesive is applied to the test panel to be bonded in form of a (round or triangular) bead, pressed

to the required thickness using a suitable thin plate and cured. A tensile force is applied to the plate

thereby peeling it off the bond in a defined angle. The reported result is the maximum force measured

It describes the adhesive strength testing of adhesives on coatings by determination of the tensile lap-

shear strength. This method yields both qualitative and quantitative results. It is suitable for testing

complete bonded assemblies as later used in practice. This also includes the use of original adherends.

The tensile lap-shear strength of overlap specimens is determined by stressing in shear of an overlap

joint between rigid adherends by applying to the adherends a tensile force which is parallel to the bond

area and to the major axis of the specimen. The reported result is the maximum force or maximum

After complete curing of the adhesive, testing is conducted according to adhesive strength test method A,

B or C, either immediately or following subsequent climatic exposure (exposure method 1 or 2).

5.1.1 Test panel, e.g. coated plates having dimensions of approximately 200 mm × 100 mm and

a thickness of 0,7 mm to 1,2 mm or coated plastic or coated glass (float glass) having a thickness of

approximately 4 mm. The thickness shall be sufficient to prevent deformation or fracture of the test

panel in combination with the specimen grip under the expected tensile load when peeling off the bead.

Specimen preparation, coating and drying/curing shall be indicated in the test report.

5.1.2 Adhesive, as agreed between the interested parties, supplied in a commercially available can.

5.1.5 Vapour barrier, e.g. strips of PE film or siliconized paper, e.g. baking paper, having dimensions

5.1.7 Cutter knife, which shall be in accordance with ISO 17872, designed as agreed between the

5.1.9 Pliers, designed as agreed between the interested parties, e.g. needle-nose pliers.

5.2.1 Test panel, e.g. coated plates having dimensions of at least 250 mm × 70 mm and a thickness

of 0,7 mm to 1,2 mm. The thickness shall be sufficient to prevent deformation of the test panel in

combination with the specimen holder under the expected tensile load when peeling off the bead.

Specimen preparation, coating and drying/curing shall be indicated in the test report.

5.2.2 Adhesive, as agreed between the interested parties, supplied in a commercially available can.

5.2.4 Strips of PE film or siliconized paper, e.g. baking paper, having dimensions of approximately

5.2.5 Peeling plate, just thick enough to enable transmission of the expected tensile forces

to the adhesive while allowing bending without using excessive force, e.g. aluminium A1050P,

5.2.7 Tensile testing machine, having a nominal load suitable for the respective adhesive bond,

The response time of the testing machine shall be sufficiently short to prevent influences on the

accuracy when measuring the force at failure. The recorded force shall not deviate from the actually

required force by more than 1 %. The testing machine shall be capable of applying the required tensile

force increasing at a steady rate. It shall be provided with a pair of suitable self-aligning grips to hold

the specimen. The grips and attachments shall be constructed such as to move into alignment with

the specimen as soon as the force is applied, so that the longitudinal axis of the specimen will coincide

with the direction of the required force through the centre line of the grip assembly to avoid bending

moment. Grips that operate by bolting through the adherends shall not be used since tearing of the

5.3.1 Test panel, e.g. coated plates having dimensions of at least 75 mm × 25 mm and a thickness

of 0,7 mm to 1,2 mm or coated plastic or coated glass (float glass) having a thickness of approximately

6 mm. The test panel strength shall be sufficient to enable transmission of the occurring tensile forces to

Specimen preparation, coating and drying/curing shall be indicated in the test report.

5.3.2 Adhesive, as agreed between the interested parties, supplied in a commercially available can.

5.3.5 Spacer, according to the agreed bond thickness or bonding frame with non-adhesive film or

5.3.6 Tensile testing machine, having a nominal load suitable for the respective adhesive bond,

The response time of the testing machine shall be sufficiently short to prevent influences on the

accuracy when measuring the force at failure. The recorded force shall not deviate from the actually

required force by more than 1 %. The testing machine shall be capable of applying the required tensile

force increasing at a steady rate. It shall be provided with a pair of suitable self-aligning grips to hold

the specimen. The grips and attachments shall be constructed such as to move into alignment with

the specimen as soon as the force is applied, so that the longitudinal axis of the specimen will coincide

with the direction of the required force through the centre line of the grip assembly to avoid bending

moment. Grips that operate by bolting through the adherends shall not be used since tearing of the

5.4.1 Apparatus for testing in a condensation atmosphere with constant humidity shall be in

5.5.1 Laboratory drying chamber, capable of maintaining the test temperature within ±2 °C (for

temperatures up to 150 °C). A laboratory drying chamber with technical ventilation shall be used.

5.5.4 Plastic bag made of polyethylene, at least 0,22 mm thick, heat resistant and sealable or

5.5.5 Deionized water, which shall be in accordance with DIN 55997, but with a maximum

Table 1 gives an overview over the sequence of adhesive strength tests A, B and C.

Pretreat the substrate to be bonded as agreed between the interested parties (clean with suitable

Store the coated test panels (5.1.1, 5.2.1 or 5.3.1) at (23 ± 2) °C and (50 ± 5) % relative humidity in

accordance with ISO 3270. The time between completion of the coating and application of the adhesive

Cut the nozzle to the base and height of the bead according to the agreed bead shape (round or triangular

For the purpose of paired measurement, apply 2 beads of the appropriately tempered adhesive parallel

Usually, exposures are conducted simultaneously, i.e. one reference test on one pair of beads and only

For elastic bonds, e.g. of windscreens where a clearance of approximately 5 mm is required, a typical

When combining several ageing tests on one pair of beads (sequential testing), the sequence, conditions

and conditioning between the individual exposures shall be specified for each ageing test. The bead

shall be long enough to provide a length of about 5 cm for reference purposes and for each test.

This method allows quick execution (“screening”) by applying round beads directly to the coating thus

causing them to cure faster due to the lack of a vapour barrier. Testing may also be conducted on uneven

Following cleaning and application of the pretreatment layer, adhesive tape may be applied to one of

the shorter sides of the test panel. This will later facilitate initial lifting of the adhesive bead. As an

During bead application, the nozzle tip shall be placed carefully on the substrate without damaging

the surface. If damage cannot be excluded, application is done near to the surface without touching it.

For this purpose, the drawing speed of the application gun and the adhesive discharge rate shall be

coordinated such as to neither stretch nor compress the adhesive in order to ensure a uniformly good

As an alternative, beads of any geometry may be applied to test areas defined by taping; excess material

The advantage of applying the adhesive bead directly to the coating including pressing is that this

ensures good contact of the adhesive with the surface. This is the method most commonly used by

laboratories. This specimen preparation simulates the curing process under real conditions where

Following the cleaning and the application of the pretreatment layer, adhesive tape may be applied to

one of the shorter sides of the test panel. This will later facilitate initial lifting of the adhesive bead. As