ICS 87.040  
 
Reference number  
DRS 300: 2021  
© RSB 2021  
  
 RWANDA 
STANDARD  DRS 
300 
 
1st edition  
2019 -mm-dd 
(Reaffirmed 2019 ) 
Epoxy resin for paints  — Specification  
 
   
DRS 300: 2021  
©RSB 2021  - 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 2021  
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized 
in any form or by any means, electronic or mechanical, including photocopying and microfilm, without 
prior written permission from R SB. 
Requests for permission to reprodu ce this document should be addressed to : 
Rwanda Standards  Board  
P.O Box 7099 Kigali -Rwanda  
KK 15 Rd, 49  
Tel. +250 788303492  
Toll Free: 3250  
E-mail: info@rsb.gov.rw  
Website: www.rsb.gov.rw  
ePortal: www.portal.rsb.gov.rw   DRS 300: 2021  
iii                ©RSB 2021  - All rights reserved  
 Contents  Page 
1 Scope  ................................ ................................ ................................ ................................ ......................  1 
2 Normative references  ................................ ................................ ................................ ............................  1 
3 Terms and definitions  ................................ ................................ ................................ ...........................  1 
4 Requirements  ................................ ................................ ................................ ................................ .........  2 
4.1 General requirements  ................................ ................................ ................................ ...........................  2 
4.2 Specific requirements  ................................ ................................ ................................ ...........................  2 
5 Packaging and labelling ................................ ................................ ................................ ........................  3 
5.1 Pack aging  ................................ ................................ ................................ ................................ ...............  3 
5.2 Labelling  ................................ ................................ ................................ ................................ .................  3 
6 Sampling  ................................ ................................ ................................ ................................ ................  4 
Annex  A (normative)  Det ermination of epoxide equivalent of epoxy compounds ................................ ..... 5 
A.1 Principle  ................................ ................................ ................................ ................................ .................  5 
A.2 Reagents  ................................ ................................ ................................ ................................ ................  5 
 DRS 300: 2021  
©RSB 2021  - All rights reserved                  iv 
 Foreword   
Rwanda Standard s are prepared  by Technical Committees and approved by R wanda 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 standards.  
The main task of technical committees is to prepare national standards.  Final Draft Rwanda S tandards 
adopted by Technical committ ees are ratifie d by me mbers of RSB Board of Director s for publication and 
gazettment as Rwanda Standards.  
DRS 300 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:  
1) IS 14925 : Epoxy resin for paints — Specification  
The assistance de rived from the above source is hereby acknowledged with thanks.  
This second  edition cancels and replaces the first edition (RS  300: 2016 ), which has been technically  revised.  
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.  
Star Construction and Consultancy Ltd  
Rwanda Inspe ctorate, Competition and Consumer Protection Authority (RICA)  
Standards for Sustainability  
Yong Rui Mei Investments Ltd  
AMACO Paints Ltd  
AMEKI Colour Ltd  
Rwanda Investigation Bureau (RIB)  
University of Rwanda/College of Sciences and Technology (UR/CST)  
University of Rwanda/College of Education (UR/CE)  DRS 300: 2021  
v                ©RSB 2021  - All rights reserved  
 Rwanda Forensic Laboratory (RFL)  
ROMAN Paints Ltd  
SHALOM Paints Ltd  
EARTHENABLE  
Rwanda  Standards Board  (RSB) – Secretariat  DRS 300: 2021  
©RSB 2021  - All rights reserved                  vi 
 Introduction   
Epoxy is the family of basic components or cured end products of epoxy resins. Epoxy resins, also known as 
polyepoxides, are a class of reactive prepolymers and polymers which contain epoxide groups.  
Two-part epoxy coatings were developed for heavy duty service on metal substrates and use less energy than 
heat-cured pow der coatings. These systems provide a tough, protective coating with excellent hardness. One  
part epoxy coatings are formulated as an emulsion in water, and can be cleaned up without solvents. Epoxy 
coatings are often used in industrial and automotive appl ications since they are more heat resistant than latex -
based and alkyd -based paints. Epoxy paints tend to deteriorate, known as "chalking out", due to UV exposure.  
 DRS 300: 2021  
1                ©RSB 2021  - All rights reserved  
 Epoxy resin for paints  — Specification  
1 Scope   
This Draft Rwanda Standard specifies the requirements, sampling and test methods for epoxy resin used in 
paint industry.  
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 reference d document (including any amendments) applies.  
ISO 4618 , Paints and varnishes — Terms and definitions  
ISO 4630, Clear liquids  — Estimation of colour by the Gardner colour scale  
ISO 3219 -1, Rheology  — Part 1: Vocabulary and symbols for rotational and oscillatory rheometry  
ISO 3219 -2, Rheology  — Part 2: General principles of rotational and oscillatory rheometry  
ISO 4625 -1, Binders for paints and varnishes  — Determination of softening point — Part 1: Ring -and-ball 
method  
ISO 4625 -2, Binders for paints an d varnishes  — Determination of softening point — Part 2: Cup -and-ball 
method  
ISO 3001 , Plastics  — Epoxy compounds — Determination of epoxy equivalent  
ISO 7142, Binders for paints and varnishes  — Epoxy resins — General methods of test  
RS OIML R 87 , Quantity  of product in pre -packages  
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 4618 and the following apply.  
3.1 
epoxy resin  
synthetic resin containing epoxide groups and in which a final polymer is formed as a result of reaction taking 
place substantially at the epoxide groups   
©RSB 2021  - All rights reserved                  2 
 3.2 
ambient temperature  
temperature between 21 °C and 38 °C 
3.3 
epoxide equivalent  
mass of an epoxide compound, in grams, which contains one mole of epoxide group  
3.4 
colour  
aspect of the appearance of objects which depends up -on the spectral composition of light reaching the retina 
of the eye and upon its temporal and spatial distribution  
4 Requirements  
4.1 General requirements  
4.1.1  The epoxy resins shall be a  condensation product of epichlorohydrin and bisphenol A in alkaline 
condition, which le ads to formation of epoxy group containing resins.  These resins shall have different 
molecular weight or epoxy equiva lent weight depending on stoichiometric ratio of above mentioned reactants. 
The manufacturer shall declare molecular distribution and average molecular weight.  
4.1.2  Depending upon the applications in paint system epoxy resins shall be classified into three types as 
detailed in Table 1 based on average molecular weight or epoxy equivalent weight when determined through 
the method specified in Annex A, along with physical state of resin.  
Table 1 – Physical state of resin  
Types  Physical state  Average 
mole cular weight  Epoxy equivalent 
weight  Test method  
Type A  Liquid  360 – 380  180 – 200  
Annex A  Type B  Low molecular weight, solid  
Grade 1  900 425 – 550  
Grade 2  1 400  850 – 1 000  
Type C  High molecular weight, solid  
Grade 1  2 900  1 700 – 2 300  
Grade 2  3 750  2 400 – 3 500  
4.2 Specific requirements  
4.2.1  Epoxy resin shall comply with the requirements specified in Table 2.  
Table 2 – Requirements for epoxy resins  
S/N Characteristic  Type A  Type B  Type C  Test DRS 300: 2021  
3                ©RSB 2021  - All rights reserved  
 Grade 1  Grade 2  Grade 1  Grade 2  method  
1 Colour (on ‘Gardener” scale), 
max.  3 4 4 4 6 ISO 4630  
2 Viscosity  a As such at 25 °C 
± 0.05 °C (cps)  8 000 – 15 000  
ISO 3219 -
1 &  
ISO 3219 -
2 b 40% in butyl 
carbitol at 25 °C 
± 0.5 °C (cps)  80 – 170  470 – 750  1 600 – 3 
400 4 000 – 
11 000  
c 50% in 1:1 
mixture of 
O.Xylene/D.A.A 
at 25 °C ± 0.5 
°C (cps)  100 – 150  
3 Softening point (ball and ring), 
°C 60 – 70  90 – 100  117 – 127  130 – 145  ISO 4625 -
1 
ISO 4625 -
2 
4 Epoxide equivalent, g/mole  180 – 200  425 – 550  850 – 
1000  1700 – 
2300  2400 – 
3500  ISO 3001  
5 Hydrolysable chlorine content, 
% by mass, max.  0.5 0.2 0.2 0.2 0.2 
ISO 7142  6 Relative density (at 27 °C ± 12 
°C) 1.15 – 1.20  
4.2.2  Storage condition  
The epoxy resins, when stored in normal condition at the ambient temperature,  shall retain its property for at 
least 12 months from the date of manufacture as prescribed in table 2.  
5 Packaging and labelling  
5.1 Packaging  
5.1.1  The epoxy resins shall be packaged in sound, clean and dry containers that prevents it from 
deterioration during storage, transportation and normal handling.  
5.1.2  The quantity of epoxy resins packaged in a container shall be in accordance with the requirements of 
RS OIML R 87.  
5.2 Labelling  
The 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 as: “Epoxy resins for paints ”; 
b) “Type” and “Grade” of the product  
c) name and address of the manufacturer and/o r registered trader mark;   
©RSB 2021  - All rights reserved                  4 
 d) net content ; 
e) batch/lot number  
f) month and year of manufacture ; 
g) instructions for use and disposal;  
h) instruction for use; and  
i) storage condition s 
6 Sampling  
Sampling shall be done in accordance with ISO 15528.  DRS 300: 2021  
5                ©RSB 2021  - All rights reserved  
 Annex  A 
(normative)  
 
Determination of epoxide equivalent of epoxy compounds  
A.1 Principle  
A.1.1  Method A  
Epoxide groups react with nascent hydrogen bromide produced by the action of a standard 0.1 mol/l solution 
of perchioric acid on tetraethyl ammonium bromide. The end -point in determined eith er by using crystal violet 
as indicator or, for dark -coloured products, by a potentiometric method. This method is recommended for 
normal reactive epoxy resin.  
A.1.2  Method B  
The amino nitrogen of the epoxyamine is titrated with a standard solution of perchloric acid. The value thus 
obtained is used as a correction in the calculation of the epoxide equivalent as obtained in Method A. this 
method is recommended for slow reactive epoxy resin.  
NOTE  Safety goggles and safety screen maybe used while carrying  out tests through the above methods.  
A.2 Reagents  
Acetic acid, glacial  
Acetic anhydride  
Suitable solvent for solution of the sample – for example, chloroform, dibutyl phthalate, chlorobenzene  
Potassium hydrogen phthalate – dry the potassium hydrogen phthalate  for 2 h at 120 °C before use  
Crystal violet, indicator solution – to 8.5 mL of a 70% (m/m) aqueous solution of perchloric acid, add 300 
mL of acetic acid followed by 20 mL of acetic anhydride. Dilute to 1 L with acetic acid and mix thoroughly, 
standardize  this solution by titrating it against 200 mg of potassium hydrogen phthalate dissolved in 50 mL of 
acetic acid, using the crystal violet indicator solution.  
Use 4 to 6 drops of the crystal violet indicator solution and continue the titration until a stabl e green colour is 
obtained.  
NOTE  The temperature, t s, of the solution of perch loric acid at the time of standardization. The concentration, C, in 
mol/l of the standard perchloric acid solution, is given by the formula HClO 4. 
  
©RSB 2021  - All rights reserved                  6 
 Bibliography  
[1] IS 354, Methods of sampling and test for resins for paints – Part 4: Special test methods for epoxy resins , 
1987  
[2] IS 1070 , Reagent grade water  — Specification (Third edition)  
 
 DRS 300: 2021  
 
Price based on 5.pages  
©RSB 2021  - All right s reserved