ICS 87.060.10  
 
Reference number  
DRS  495-2: 2022 
© RSB 2022 
  
 RWANDA 
STANDARD  DRS  
495-2  
 
First edition  
2022 -mm-dd 
 
Organic pigments for paints  — 
Specification  — 
Part 2: 
Phthalocyanines  
   
DRS 495 -2: 2022 
©RSB 2022 - All rights reserved                  ii 
 In order to match with technological development and to keep continuous progress in industries, 
standards are subject to periodic review. Users shall ascertain that they are in possession of the latest 
edition  
 
 
 
 
 
 
 
 
© RSB 2022 
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ePortal: www.portal.rsb.gov.rw   DRS 495 -2: 2022 
iii                ©RSB 2022 - All rights reserved  
 Contents  Page 
Foreword  ................................ ................................ ................................ ................................ ............................  iv 
1 Scope  ................................ ................................ ................................ ................................ ......................  1 
2 Normative references  ................................ ................................ ................................ ............................  1 
3 Terms and definitions  ................................ ................................ ................................ ...........................  2 
4 Types  ................................ ................................ ................................ ................................ ......................  2 
5 Requirements  ................................ ................................ ................................ ................................ .........  2 
5.1 General requirements  ................................ ................................ ................................ ...........................  2 
5.2 Specif ic requirements  ................................ ................................ ................................ ...........................  2 
6 Packaging and labelling ................................ ................................ ................................ ........................  4 
6.1 Packaging  ................................ ................................ ................................ ................................ ...............  4 
6.2 Labelling  ................................ ................................ ................................ ................................ .................  4 
7 Sampling  ................................ ................................ ................................ ................................ ................  4 
Annex  A (normative)  Annex title  ................................ ................................ ................................ ......................  5 
A.1 General  ................................ ................................ ................................ ................................ ...................  5 
A.2 Reagents  ................................ ................................ ................................ ................................ ................  5 
A.3 Procedure  ................................ ................................ ................................ ................................ ...............  5 
Annex  B (normative)  Resistance to crystallization and flocculation test  ................................ ...................  7 
B.1 General  ................................ ................................ ................................ ................................ ...................  7 
B.2 Apparatus  ................................ ................................ ................................ ................................ ...............  7 
B.3 Reagents  ................................ ................................ ................................ ................................ ................  7 
B.4 procedure  ................................ ................................ ................................ ................................ ...............  7 
 DRS 495 -2: 2022 
©RSB 2022 - All rights reserved                  iv 
 Foreword   
Rwanda Standard s are prepared  by Technical Committees and approved by Rwanda Standards Board (RSB) 
Board  of Directors in  accordance with the procedures of RSB, in compliance with Annex 3 of the WTO/TBT 
agreement on the preparation, adoption and application of sta ndards.  
The main task of technical committees is to prepare national standards.  Final Draft Rwanda S tandards 
adopted by Technical committ ees are ratified  by me mbers of RSB Board of Director s for publication and 
gazettment as Rwanda Standards.  
DRS 495 -2 was prepared by Technical Committee RSB/TC 056, Paints, varnishes, Adhesives and Related 
Products . 
In the preparation of this standard, reference was made to the following standard:  
IS 3574 (Part 2) : Organic pigments for paints — Specification — Part 2: P hythalocyanines  
The assistance de rived from the above source is hereby acknowledged with thanks.  
DRS  495 consists of the following parts, under the general title Organic pigments for paints — Specification : 
⎯ Part 1: Azo pigments  
⎯ Part 2: Phthalocyanines  
Committee membership  
The following organizations were represented on the Technical Committee on Paints, varnishes, Adhesives 
and Related Products  (RSB/TC 056) in the preparation of this standard.  
University of Rwanda/College of Sciences and  Technology (UR/CST)  
University of Rwanda/College of Education (UR/CE)  
EARTHENABLE  
Standards for Sustainability (SfS)  
AMACO Paints  
Rwanda Inspectorate, Competition and Consumer Protection Authority (RICA)  
REX Paints  DRS 495 -2: 2022 
v                ©RSB 2022 - All rights reserved  
 Star Construction and Consultancy Ltd  
IPRC Kigali  
MEI Paints  
Rwanda  Standards Board  (RSB) – Secretariat  DRS 495 -2: 2022 
©RSB 2022 - All rights reserved                  vi 
 Introduction   
Phthalocyanine pigments have attained a distinct position in organic dyes for paints where clear tone, high 
light fastness and chemical inertness are required.  
Phthalocyanine  (H2Pc) is a large , aromatic, macrocyclic, organic compound  with the formula  (C8H4N2)4H2 and 
is of theoretical or specialized interest in chemical dyes and photoelectricity. It is composed of four  
isoindole  units  linked by a ring of nitrogen atoms.  (C8H4N2)4H2 = H2Pc has a two -dimensional geometry and a 
ring system consisting of 18  π-electrons . The extensive  delocalization  of the π -electrons affords the molecule 
useful properties, lending itself to applications in dyes and pigments.  Metal complexes  derived from  Pc2−, the 
conjugate base of  H2Pc, are valuable in  catalysis , organic solar cells , and  photodynami c therapy  
 
 
 
 DRS 495 -2: 2022 
1                ©RSB 2022 - All rights reserved  
 Organic pigments for paints  — Specification  — Part 2: Phthalocyanines  
1 Scope   
This Draft Rwanda Standard  prescribes requirements, sampling and test methods for phthalocyanine 
pigments used in paints and related products. It applies to 9 types of pigments as it is described in clause 4.  
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 18451 -1, Pigments, dyestuffs and extenders — Terminology — Part 1: General terms  
ISO 18451 -2, Pigments, dyestuffs and extenders — Terminology — Part 2: Classification of colouring 
materials according to colouristic and chemical aspects  
ISO 787 -7, General methods of test for pigments and extenders — Part 7: Determination of residue on sieve — 
Water method — Manual procedure  
ISO 787 -2, General methods of test for pigments and extenders — Part 2: Determination of matter volatile at 
105 degrees C  
ISO 7 87-3, General methods of test for pigments and extenders — Part 3: Determination of matter soluble in 
water — Hot extraction method  
ISO 787 -9, General methods of test for pigments and extenders — Part 9: Determination of pH value of an 
aqueous suspension  
ISO 787 -5, General methods of test for pigments and extenders — Part 5: Determination of oil absorption 
value  
ISO 787 -25, General methods of test for pigments and extenders — Part 25: Comparison of the colour, in full -
shade systems, of white, black and colo ured pigments — Colorimetric method  
ISO 787 -15 General methods of test for pigments and extenders — Part 15: Comparison of resistance to light 
of coloured pigments of similar types  
ISO 787 -21, General methods of test for pigments and extenders — Part 21: C omparison of heat stability of 
pigments using a stoving medium  
ISO 7579, Dyestuffs — Determination of solubility in organic solvents — Gravimetric and photometric methods  
RS OIML R 87 , Quantity of product in pre -packages   
©RSB 2022 - All rights reserved                  2 
 ISO 15528 , Paints, varnishes and raw materials for paints and varnishes — Sampling  
3 Terms and definitions   
For the purposes of this standard, the terms and definitions given in ISO 18451 -1, ISO 18451 -2 and the 
following apply.  
3.1 
term  
text of the definition  
4 Types  
The 9 types  of phthalocyanine pigments covered by this standard are described in table 1:  
Name of pigment  Cristal modification  Remarks  
Pigment Blue 15  Alpha  Solvent unstable  
Pigment Blue 15.1  Alpha  Non-crystallizing  
Pigment Blue 15.2  Alpha  Non-crystallizing, non -flocculating  
Pigment Blue 15.3  Beta Non-crystallizing  
Pigment Blue 15.4  Beta Non-crystallizing, non -flocculating  
Pigment Blue 15.6  Epsilon  - 
Pigment Blue 16  - Metal free phthalocyanine  
Pigment Green 7  - Chlorinated  
Pigment Green 36  - Partially brominated  
5 Requirements  
5.1 General requirements  
5.1.1  The pigment shall be in the form of fine dry powder and free from grit or shall be in such condition 
that can be readily reduced to powder form by crushing under a pallet knife, without any grinding action. Low 
dusting type organic pigments in the form of soft granules, may be also acceptable.  
5.1.2  The pigment dried shall essentially consist of copper phthalocyanine or copper free phthalocyanine 
or polychloro/haloge nated phthalocyanine. Presence of other ingredients, free from organic or inorganic 
colouring matter, incorporated during manufacturing process to improve pigmenting properties, constituting 
more than 5% of total pigment, by mass, shall be declared.  
5.2 Speci fic requirements  
The pigments shall comply with the requirements given in table 2 when tested in accordance with the methods 
prescribed therein.  DRS 495 -2: 2022 
3                ©RSB 2022 - All rights reserved  
 Table 2 — Specific requirements for phthalocyanine pigments for paints  
S/N Parameters  Requirements  Test methods  
1 Residue, (on sieve 325 mesh), % by mass, 
max.  0.1 ISO 787 -7 
2 Volatile matter, % by mass, max.  1.0 ISO 787 -2 
3 Matter soluble in water, % by mass, max.  1.0 ISO 787 -3 
4 pH of aqueous extract (but within ± 1% of 
value of approved sample)  5 – 9 ISO 787 -9 
5 Oil absorption (but within ± 1% of value of 
approved sample)  30 – 50 ISO 787 -5 
6 Colour by visual 
assessment  Transparency/opacity  Close match to the 
approved sample  ISO 787 -25 
Shade (hue)  Do 
Dullness/brightness 
(chroma)  Do 
Colour strength  Close match to the 
approved sample but 
within ± 5% of value of 
approved sample  
7 Colour by spectro 
photometry1 Lightness/darkness, dL  As agreed between 
purchaser and supplier but 
within ± 0.5 % CIELAB Unit  ISO 787 -25 
Dullness/brightness, 
dC. As agreed between 
purchaser and supplier but 
within ± 0.5 % CIELAB Unit  
Shade, dH  As agreed between 
purchaser and supplier but 
within ± 0.5 % CIELAB Unit  
Colour strength  As agreed between 
purchaser and supplier but 
within ± 0.5 % of approved 
standard  
Total colour difference, 
dE As agreed between 
purchaser and supplier but 
within  1 – 2 of CIE Unit  
8 Light and weather fastness  Not inferior to approved 
standard sample  ISO 787 -15 
9 Acid/alkali resistance  Do Annex A  
10 Heat resistance  Do ISO 787 -21 
11 Solvent fastness  Do ISO 7579  
12 Resistance to crystallization and flocculation  Do Annex B  
1 These parameters may be tested, if specified by purchaser, tu support visual assessment, using a suitable spectrophotometer . 
  
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 6 Packaging and labelling  
6.1 Packaging   
6.1.1  The pigment  shall be packaged in a suitable container that prevents it from deterioration during 
storage, transportation and normal handling.  
6.1.2  The quantity of product packaged in a container shall be in accordance with the requirements of RS 
OIML R 87.  
6.2 Labelling  
6.2.1  Each container shall be labell ed legibly and indelibly with the following  information in any of the three 
languages officially accepted in the Republic of Rwanda namely: Kinyarwanda, French and English:  
a) name of the product ; 
b) name and address  of the manufacturer and/or registered trader mark;  
c) net content ; 
d) organic/inorganic colouring matter, % by mass, if added;  
e) batch number  
f) manufacture and expiry d ates; 
g) instructions for use and disposal;  
h) special precautions , if any ; and 
i) storage condition  
7 Sampling  
Sampling shall be done in accordance with ISO 15528 . 
 DRS 495 -2: 2022 
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 Annex  A 
(normative)  
 
Acid and alkali resistance test  
A.1 General  
Resistance to acids and alkalis is determined by treating the material under test and the approved sample with 
dilute hydrochlori c acid and dilute sodium hydroxide solution, respectively. The change in the colour and 
staining power of the material thus treated is compared with the change observed in the case of the approved 
sample, similarly treated, and tested against the original.  
A.2 Reagents  
A.2.1  Diluted hydrochloric acid  – Dilute 6mL of hydrochloric acid AR 35% to 100 mL with water.  
A.2.2  Sodium Hydroxide solution  – 10% (m/v)  
A.3 Procedure  
A.3.1  Resistance to acid  
A.3.1.1  Carry out the test with approved sample and test sample simultaneously. Weigh 1.0 g pigment under 
test on a Whatman No. 1 filter paper or equivalent (10 cm x 10 cm). Fold it (as shown in Figure 1) then fold in 
another direction with the sides overlapping a nd tie it with a string (keeping one end free and long) so as to 
enclose the pigment fully protecting it from coming out. Immense the pigment packet so prepared, suspending 
at about the middle in 50 mL dilute hydrochloric acid taken in a Nessler’s test tub e of about 2.5 cm dia and 16 
cm height. The extended string can be used for shifting and lifting the packet in acid. Close the test tube with a 
cork and maintain at room temperature for 24 h or in a water bath at 50 ˚C for 2 h. Temperature and duration 
can be changed, as desired, depending upon mutually agreed requirements. Take out the pigment packet and 
shake the tube to make the acid solution uniform. Compare the colouration of bleed, if any, between the 
samples.  
A.3.1.2  Wash the treated pigment in the packet with water till free of acid, dry at 100 ± 2 ˚C on an oven. Test 
this dried pigment against untreated pigment and compare the change with that obtained in the case of the 
approved sample when similarly treated and tes ted.  
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Figure 1 – Folding of filter paper  
A.3.2  Resistance to alkali  
Repeat the test by taking dilute sodium hydroxide solution in place of dilute acid in the test method for 
resistance to acid.  
 
  
DRS 495 -2: 2022 
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 Annex  B 
(normative)  
 
Resistance to crystallization and flocculati on test  
B.1 General  
Phthalocyanine pigments are directly responsible for loss of staining power or fading due to crystallization 
which may be accentuated by effects of other pigments or the medium used. To ascertain this property, the 
material is examined for change in crystal shape and size after refluxing with a strong solvent like xylol. 
Further this property is tested by comparing the actual performance of a tinted enamel prepared from the 
material and an agreed medium with that prepared using the approved sample of the pigment and the same 
medium.  
B.2 Apparatus  
B.2.1  Flat-Bottomed Flask , 250 mL, capacity . 
B.2.2  Microscope  
B.3 Reagents  
B.3.1  Xylol  
B.3.2  Titanium dioxide , Rutile for paints.  
B.3.3  Medium short oil alkyd , dissolved in xylol or any other medium as may b e agreed to between the 
purchaser and the supplier.  
B.4 procedure  
B.4.1  Testing for resistance to crystallization  
B.4.1.1  Take about 0.5 g of the pigment in a 250 mL flask and wet it with about 50 mL of xylol. Reflux the 
contents of the flask for 3 h at 140 ˚C in a glycerine or oil bath. At the end of this period, remove the flask from 
the bath and cool the contents. Place fe w drops of this slurry on a microscope slide. On the same slide, place 
few drops of the prepared sample with xylol as a control. Examine the two patches under a microscope, at 
400 times magnification . Observe the change in the crystal shape and size of the  sample under test with the 
prepared sample. Similarly note the change in the crystal structure and size of the approved sample when 
similarly treated.  
B.4.1.2  Filter the remaining slurry of the treated sample through a filter paper and keep separately. Pr epare a 
suspension of the prepared sample in xylol and filter the suspension. Check the colour of this filtrate with that 
obtained after filtration of the treated sample and note bleeding, if any, of both the samples against that of 
approved samples when s imilarly treated.   
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 B.4.1.3  Dry the residue obtained after refluxing with xylol as prescribed in B.4.1.1 on the filter paper in an 
oven maintained at 100 ± 2 ˚C for 1h. Compare the staining power of the treated sample against that of the 
prepared sample. Det ermine the loss in the case of the approved sample treated similarly.  
B.4.2  Testing for resistance to flocculation  
Prepare a tinted enamel using the material and surface treated rutile titanium dioxide  in the proportion of 
1:100 in the short oil alkyd medium by grinding in a ball -mill or any other suitable equipment. After ensuring 
thorough grinding of the enamel, reduce it by addition of thinners to spraying consistency. Apply this enamel 
by spraying o n mild steel panel. Rub one corner of the sprayed film with the finger just before it is surface dry. 
Allow the remaining portion of the material to stand for half an hour. At the end of this period stir the enamel 
and pour a small quantity over a portion of the sprayed film. Allow it to dry. Observe the difference in colour 
between the sprayed and rubbed portion of the enamel film with the area on which additional enamel was 
poured and compare the difference observed against that obtained in the case of th e approved sample, 
similarly treated at the same time.  
 DRS 495 -2: 2022 
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 Bibliography  
[1] IS 3493 , Method of sampling and test for organic pigments for paints , 1978  
[2]  
 DRS 495 -2: 2022 
 
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