SIST EN ISO 6504-1:2019
(Main)Paints and varnishes - Determination of hiding power - Part 1: Kubelka-Munk method for white and light-coloured paints (ISO 6504-1:2019)
Paints and varnishes - Determination of hiding power - Part 1: Kubelka-Munk method for white and light-coloured paints (ISO 6504-1:2019)
This document specifies a method for determining the hiding power (spreading rate necessary to give
a hiding power of 98 %) of white or light-coloured paints. It is applicable to paint films having the tristimulus
value of Y ≥ 70 and hiding power > 80 %. It is not applicable to fluorescent or metallic paints.
Beschichtungsstoffe - Bestimmung des Deckvermögens - Teil 1: Verfahren nach Kubelka-Munk für weiße und helle Beschichtungen (ISO 6504-1:2019)
Dieses Dokument legt ein Verfahren zum Bestimmen des Deckvermögens von weißen und hellen Beschichtungen (bei einer Ergiebigkeit, die ein Deckvermögen von 98 % ergibt) fest. Das Verfahren ist auf Beschichtungen mit einem Normfarbwert Y ≥ 70 und einem Deckvermögen > 80 % anwendbar. Es ist nicht anwendbar auf fluoreszierende Beschichtungsstoffe oder Metallic-Beschichtungsstoffe.
Peintures et vernis - Détermination du pouvoir masquant - Partie 1: Méthode de Kubelka-Munk pour les peintures blanches et les peintures claires (ISO 6504-1:2019)
Le présent document spécifie une méthode pour déterminer le pouvoir masquant (rendement surfacique nécessaire pour obtenir un pouvoir masquant de 98 %) des peintures blanches ou claires. Elle est applicable aux feuils de peinture ayant une composante trichromatique Y ≥ 70 et un pouvoir masquant > 80 %. Elle n'est pas applicable aux peintures métalliques ou fluorescentes.
Barve in laki - Ugotavljanje kritnosti - 1. del: Metoda po Kubelka-Munku za bele in pastelne nianse (ISO 6504-1:2019)
Ta dokument določa metodo za ugotavljanje kritnosti (hitrost nanašanja, ki je potrebna za 98-odstotno kritnost) belih in pastelnih nians. Uporablja se za barvne plasti s trikromatsko vrednostjo Y ≥ 70 in kritnostjo > 80 %. Ne uporablja se za fluorescentne ali kovinske nianse.
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN ISO 6504-1:2019
01-september-2019
Nadomešča:
SIST EN ISO 6504-1:2006
Barve in laki - Ugotavljanje kritnosti - 1. del: Metoda po Kubelka-Munku za bele in
pastelne nianse (ISO 6504-1:2019)
Paints and varnishes - Determination of hiding power - Part 1: Kubelka-Munk method for
white and light-coloured paints (ISO 6504-1:2019)
Beschichtungsstoffe - Bestimmung des Deckvermögens - Teil 1: Verfahren nach
Kubelka-Munk für weiße und helle Beschichtungen (ISO 6504-1:2019)
Peintures et vernis - Détermination du pouvoir masquant - Partie 1: Méthode de
Kubelka-Munk pour les peintures blanches et les peintures claires (ISO 6504-1:2019)
Ta slovenski standard je istoveten z: EN ISO 6504-1:2019
ICS:
87.040 Barve in laki Paints and varnishes
SIST EN ISO 6504-1:2019 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST EN ISO 6504-1:2019
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SIST EN ISO 6504-1:2019
EN ISO 6504-1
EUROPEAN STANDARD
NORME EUROPÉENNE
June 2019
EUROPÄISCHE NORM
ICS 87.040 Supersedes EN ISO 6504-1:2006
English Version
Paints and varnishes - Determination of hiding power -
Part 1: Kubelka-Munk method for white and light-coloured
paints (ISO 6504-1:2019)
Peintures et vernis - Détermination du pouvoir Beschichtungsstoffe - Bestimmung des Deckvermögens
masquant - Partie 1: Méthode de Kubelka-Munk pour - Teil 1: Verfahren nach Kubelka-Munk für weiße und
les peintures blanches et les peintures claires (ISO helle Beschichtungen (ISO 6504-1:2019)
6504-1:2019)
This European Standard was approved by CEN on 13 May 2019.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, North
Macedonia, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United
Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2019 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 6504-1:2019 E
worldwide for CEN national Members.
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SIST EN ISO 6504-1:2019
EN ISO 6504-1:2019 (E)
Contents Page
European foreword . 3
2
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SIST EN ISO 6504-1:2019
EN ISO 6504-1:2019 (E)
European foreword
This document (EN ISO 6504-1:2019) has been prepared by Technical Committee ISO/TC 35 "Paints
and varnishes" in collaboration with Technical Committee CEN/TC 139 “Paints and varnishes” the
secretariat of which is held by DIN.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by December 2019, and conflicting national standards
shall be withdrawn at the latest by December 2019.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 6504-1:2006.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta,
Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.
Endorsement notice
The text of ISO 6504-1:2019 has been approved by CEN as EN ISO 6504-1:2019 without any
modification.
3
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SIST EN ISO 6504-1:2019
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SIST EN ISO 6504-1:2019
INTERNATIONAL ISO
STANDARD 6504-1
Second edition
2019-05
Paints and varnishes — Determination
of hiding power —
Part 1:
Kubelka-Munk method for white and
light-coloured paints
Peintures et vernis — Détermination du pouvoir masquant —
Partie 1: Méthode de Kubelka-Munk pour les peintures blanches et les
peintures claires
Reference number
ISO 6504-1:2019(E)
©
ISO 2019
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SIST EN ISO 6504-1:2019
ISO 6504-1:2019(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2019
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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Phone: +41 22 749 01 11
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2019 – All rights reserved
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SIST EN ISO 6504-1:2019
ISO 6504-1:2019(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 1
5 Kubelka-Munk equations . 2
6 Apparatus and materials. 3
6.1 Substrates . 3
6.1.1 Determination of R . 3
B
6.1.2 Determination of R . 4
∞
6.2 Film applicators . 4
6.3 Reflectometer . 4
6.4 Template . 4
7 Limitations . 4
8 Sampling . 4
9 Procedure. 4
9.1 Determination of R . 4
∞
9.2 Determination of R . 5
B
9.2.1 Preparation of test films . 5
9.2.2 Measurement of reflectance R . 5
B
9.3 Determination of film thickness . 6
9.3.1 General. 6
9.3.2 Method using polyester film . 6
9.3.3 Method using black glass plates . 6
10 Expression of results . 6
10.1 Calculation of wet film thickness . 6
10.2 Calculation of hiding power . 7
11 Precision . 7
11.1 Repeatability (r) . 7
11.2 Reproducibility (R) . 7
12 Test report . 7
Annex A (informative) Graphs for determination of St from R and R for R = 0,80 .8
B ∞ g
Annex B (informative) Table of values of reflectivity R and factor α for R = 0,80 .33
∞ g
Annex C (informative) Examples of the calculation of hiding power from measurements of
R and R .34
B ∞
Bibliography .36
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SIST EN ISO 6504-1:2019
ISO 6504-1:2019(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 35, Paints and varnishes, Subcommittee
SC 9, General test method for paints and varnishes.
This second edition cancels and replaces the first edition (ISO 6504-1:1983), which has been technically
revised. The main changes compared to the previous edition are as follows:
a) the normative references in Clause 2 have been updated;
b) Clause 3 for terms and definitions has been added;
c) Clause 7 for limitations has been added;
d) the term "contrast ratio" has been changed to "hiding power" throughout the text;
e) it has been clarified that the reflectance R needs to be measured and that the graphs in Annex A
g
and values in Table B.1 are only examples for R = 0,80.
g
A list of all parts in the ISO 6504 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.
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SIST EN ISO 6504-1:2019
ISO 6504-1:2019(E)
Introduction
[1]
ISO 6504-3 specifies a method for determining the hiding power of paints at a fixed spreading rate,
by applying paint films to black and white charts and to polyester film respectively. It depends on the
observation that there is a linear relationship between hiding power and reciprocal film thickness, at
least over a limited range of film thickness.
Hiding power of paints is generally defined as the spreading rate required to give a hiding power of
[1]
98 %. To determine this by the method specified in ISO 6504-3 would be time-consuming and require
considerable extrapolation which often exceeds the limit of linearity of the relationship between hiding
power and spreading rate. Therefore, this method for the determination of hiding power, involving
the Kubelka-Munk (K-M) equations which relate scattering and absorption coefficients to optical
properties, has also been standardized.
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SIST EN ISO 6504-1:2019
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SIST EN ISO 6504-1:2019
INTERNATIONAL STANDARD ISO 6504-1:2019(E)
Paints and varnishes — Determination of hiding power —
Part 1:
Kubelka-Munk method for white and light-coloured paints
1 Scope
This document specifies a method for determining the hiding power (spreading rate necessary to give
a hiding power of 98 %) of white or light-coloured paints. It is applicable to paint films having the tri-
stimulus value of Y ≥ 70 and hiding power > 80 %. It is not applicable to fluorescent or metallic paints.
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 1513, Paints and varnishes — Examination and preparation of test samples
ISO 2808, Paints and varnishes — Determination of film thickness
ISO 2811-1, Paints and varnishes — Determination of density — Part 1: Pycnometer method
ISO 3251, Paints, varnishes and plastics — Determination of non-volatile-matter content
ISO 4618, Paints and varnishes — Terms and definitions
ISO 15528, Paints, varnishes and raw materials for paints and varnishes — Sampling
3 Terms and definitions
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:
— IEC Electropedia: available at http: //www .electropedia .org/
— ISO Online browsing platform: available at https: //www .iso .org/obp
3.1
light-coloured paint
coating with tristimulus values Y and Y greater than 25, measured with a spectrophotometer on a
10
black and white substrate
4 Principle
The method is based on the Kubelka and Munk equations relating the scattering and absorption
coefficients of pigmented films to their colour and opacity.
For the determination of hiding power, both the reflectance (R ) of a paint film of thickness t on a black
B
background and the reflectivity (R ) are required for introduction into the Kubelka-Munk equations
∞
(Clause 5).
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SIST EN ISO 6504-1:2019
ISO 6504-1:2019(E)
5 Kubelka-Munk equations
The Kubelka-Munk (K-M) equations required are
1 1
aR=+ (1)
∞
2 R
∞
ba=−R (2)
∞
1
R = (3)
B
ab+ cothbSt
1−−Ra bbcoth St
()
g
R= (4)
ab+−cothbStR
g
where
R is the reflectivity, i.e. the reflectance of a paint film of such thickness that further increase in
∞
thickness gives no further change in reflectance;
R is the reflectance of a paint film of thickness t applied over a black background;
B
R is the reflectance of a paint film of thickness t applied over a white background of determined
reflectance R ;
g
−1
S is the scattering coefficient per micrometre (µm );
t is the thickness, in micrometres, of the paint film.
When using Formulae (1) to (4) with this method, the measured CIE tristimulus values Y divided by 100
are inserted for R, R and R , respectively.
B ∞
The hiding power V is the spreading rate necessary to give a hiding power (R /R) of 0,98, and is
0,98 B
determined via the equivalent film thickness t according to the formula
0,98
1000
V =
t
where
V is the hiding power, in square metres per litre;
t is the thickness, in micrometres, of the wet paint film.
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SIST EN ISO 6504-1:2019
ISO 6504-1:2019(E)
From Formulae (3) and (4), when the hiding power (R /R) is equal to 0,98
B
ab−+08, cothbSt
09, 8
=09, 8
ab+ cothbSta10−−,c8 bboth St
{}
09,,80 98
or after, rearrangement
1 0,02+ D
t = arcoth (5)
09, 8
bS 1,568 b
where
D = 3,136 a [1 − 0,98(1 − 0,8a)] − 2,508 4
and
1000 1000bS
V == =∝S (6)
t
00, 2+ D
arcoth
1,568b
NOTE 1 If y = coth x, x = arcoth y.
NOTE 2 It can be seen that for constant values of R and hiding power (V ), factor α is a function of R .
g 0,98 ∞
The scattering coefficient S is determined from a rearrangement of Formula (3), the values of a and b
being known by calculation from Formulae (1) and (2) respectively, as follows:
1−aR
1
B
St = arcoth (7)
b bR
B
To simplify the calculations, graphs are available for the determination of the product St from measured
values of R and R .
g ∞
The scattering coefficient S is calculated by dividing St by the film thickness t, and V is obtained
0,98
from Formulae (5) and (6). A table of values of α for various values of R (see Table B.1) simplifies the
∞
calculation.
NOTE 3 Suitable tables and graphs are for example referred to in ASTM D2805. Table B.1 is taken, with
[2]
modifications, from ASTM D2805–80 and the graphs in Annex A are from Reference [3].
6 Apparatus and materials
6.1 Substrates
6.1.1 Determination of R
B
6.1.1.1 Glass plates, black, plane, polished, not less than 6 mm thick and of dimensions at least
200 mm × 200 mm, or
6.1.1.2 Polyester film, clear, untreated, transparent, of uniform thickness between 30 µm and 100 µm,
and of dimensions at least 100 mm × 150 mm, together with a glass plate as specified in 6.1.1.1.
NOTE Commercially available polyester sheet has been found to be satisfactory.
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SIST EN ISO 6504-1:2019
ISO 6504-1:2019(E)
6.1.2 Determination of R
∞
6.1.2.1 Smooth surfaced paper charts, readily wetted by, but impervious to, solvent and water
thinned paints, and similar in reflectance to the paint to be tested.
Suitable chart colours are grey for paints of low reflectivity and white for paints of high reflectivity.
Alternatively, ceramic tiles or glass may be used.
6.2 Film applicators
A series of film applicators giving films of uniform thickness within the range 40 µm to 150 µm is
required. For application to glass, bar applicators are suitable. For application to polyester film or paper
charts, wirewound applicators are more suitable.
The film laid down shall be at least 150 mm wide (using glass) or 70 mm wide (using polyester film) to
cover areas, at a uniform thickness, of at least 100 mm × 125 mm or 60 mm × 60 mm respectively. The
application of uniform films is facilitated by the use of automatic applicators, which are recommended.
6.3 Reflectometer
A photoelectric instrument is required, giving an indicated reading proportional to the intensity of
light reflected from the surface under test to an accuracy of 0,1 % of full scale deflection, and having a
spectral response approximating to the product of the relative spectral energy distribution of CIE
standard illuminant D 65 and the colour matching function y (λ) of the CIE standard observer.
lt is recognized that the relative geometrical arrangement of the illuminating beam and the light
detector can affect the measurement of reflectance, but it is considered that variations arising from this
factor in commercial reflectometers should be considerably less than the figures for reproducibility
stated in 11.2. In the event of dispute, 8°/diffuse geometry, without gloss trap, should be used.
For other than reference purposes, CIE illuminant C may be used.
6.4 Template
A rectangular metal template with minimum dimensions of 100 mm × 125 mm is required for films
applied to black glass. For films on polyester film, a metal template or die stamp with minimum
dimensions of 60 mm × 60 mm is required.
7 Limitations
Temperature and humidity are important parameters affecting test results. Deviations from the
requirements specified can lead to results that are not comparable. However, the interested parties
may agree upon alternative parameters and these parameters shall be reported.
8 Sampling
Take a representative sample of the product to be tested as described in ISO 15528.
Examine and prepare the sample for testing as described in ISO 1513.
9 Procedure
9.1 Determination of R
∞
Measure the reflectance R of the uncoated paper substrate. Apply a few millilitres of the paint sample
g
in a line across one end of a paper substrate and spread it immediately by drawing down a suitable
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SIST EN ISO 6504-1:2019
ISO 6504-1:2019(E)
applicator at a steady rate so as to give a uniform film thickness. Repeat the operation so as to provide
uniform films having dry film thicknesses of about 75 µm, 100 µm, 125 µm and 150 µm. Dry the paint as
described in 9.2.1.4. Measure the reflectance of each paint film at four positions on each coated paper.
Record the value of reflectance which is independent of the film thickness as the reflectivity R .
∞
If the reflectance is still increasing when the film thickness reaches 150 µm, further coats should be
applied until a constant reflectance is obtained.
9.2 Determination of R
B
9.2.1 Preparation of test films
9.2.1.1 General
Apply a film thickness that will give a dry film having a reflectance at least 0,02 lower than the
reflectivity R of the paint sample.
∞
9.2.1.2 Method using polyester film
Prepare the polyester film (6.1.1.2) for coating by either
a) spreading it on a black glass plate (6.1.1.1) which has first been moistened with just sufficient white
spirit (a few drops), to hold the film in position by surface tension. Ensure that none of the liquid
wets the upper surface of the film and that no air bubbles are trapped under it;
or, if wirewound applicators are to be used
b) by fixing the polyester film at one end and laying it over a flat rubber block.
Apply a few millilitres of the paint sample, according to the film thickness required, in a line across one
end of the polyester film and spread it immediately by drawing down a suitable applicator at a steady
rate to give a uniform film thickness. Prepare a total of four test films in this way.
9.2.1.3 Method using black glass plates
Apply a few millilitres of the paint sample in a line across one end of a black glass plate (6.1.1.1) and
spread it immediately by drawing down a suitable applicator at a steady rate to give a uniform film
thickness. Repeat the application with different black glass plates (6.1.1.1) until four uniform films of
approximately the same thickness have been prepared.
9.2.1.4 Drying and conditioning
With the coated substrates in a horizontal position, dry the paint by the appropriate procedure for
the type of paint or as agreed between the parties. Maintain the dried test films at a temperature of
(23 ± 2) °C in a dust free atmosphere having a relative humidity of (50 ± 5) % for at least 24 h, but not
more than 168 h, before carrying out the reflectance measurements.
9.2.2 Measurement of reflectance R
B
9.2.2.1 General
Variation in readings is likely to be the result of non-uniform application of the paint film and is
dependent on the techniques used. If the precision (Clause 11) is not obtained, the technique should be
re-examined.
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SIST EN ISO 6504-1:2019
ISO 6504-1:2019(E)
9.2.2.2 Method using polyester film
Fix the coated polyester films over a black glass plate, introducing a few drops of white spirit between
the underside of the film and the glass to ensure optical contact. Measure the reflectance of the test
films at a minimum of four positions and calculate the mean reflectance R of each coated plate.
B
9.2.2.3 Method using black glass plates
Measure the reflectance R directly by means of the reflectometer (6.3), taking readings at a minimum
B
of four positions on each coated plate, avoiding its edges, and calculate the mean reflectance R of each
B
coated plate.
9.3 Determination of film thickness
9.3.1 General
The method using polyester film
...
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