Reference number  
DRS  300: 2016  
© RBS yyyy 
© RSB 2016  
 
 RWANDA 
STANDARD  DRS 
300 
 
First edition  
2016 -mm-dd 
 
Epoxy resin for paints — Specification  
 
  DRS 300: 2016  
©RSB 2016 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  
 
 
 
 
 
 
 
 
 
 
© RSB2016  
All rights reserved. Unless otherwise speci fied, 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 reproduce this document shoul d be addressed to  
Rwanda Standards  Board  
P.O Box 7099 Kigali -Rwanda  
Tel. +250 252 586103/582945  
E-mail: info@rsb.gov.rw  
Website: www.rsb.gov.rw  DRS 300 : 2016  
iii                 ©RSB2016 A ll rights reserved  
 
 Contents  Page 
1 Scope  ................................ ................................ ................................ ................................ ......................  1 
2 Normative references  ................................ ................................ ................................ ............................  1 
3 Terms and definitions  ................................ ................................ ................................ ...........................  1 
4 Requ irements  ................................ ................................ ................................ ................................ .........  5 
5 Packaging and marking  ................................ ................................ ................................ ........................  7 
Annex  A (informative)  Method of determination of epoxide equivalent of epoxy compounds  ................  8 
 DRS 300: 2016  
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 Foreword  
Rwanda Standard sareprepared by Technical Committees and approved by R wanda Standards Board (RSB) 
Board  of Directors in  accordance with the procedures of RSB, in compliance with An nex 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 ratified by me mbers of RSB Board of Director s for publication and 
gazettment as Rwanda Standards.  
DRS300  was prepared by Technical Committee RSB/TC 024, Chemical and consumer products . 
In the preparation of this standard, reference was made to the following standard s: 
1) IS 14925: 2001, Epoxy resin for paints — Specification  
2) IS 1303: 2001, Glossary of terms relating to paints  
The assistance de rived from the above source is hereby acknowledged with thanks.  
Committee membership  
The following organizations were represented on the Technical Committee on Chemical s and consumer 
products  (RSB/TC 024) in the preparation of this standard.  
Amaco Paints Company Ltd  
AMEKI COLORS Ltd  
Crown Paints Rwanda Ltd  
Institute of Agriculture, Technology and Education of Kibungo (INATEK)  
Integrated Polytechnic Regional Center — Kicukiro Campus (IPRC — Kicukiro Campus)  
Ministry of Health (MINISANTE)  
National Industrial Research and Development Agency (NIRDA)  
Rwanda Environment Management Authority (REMA)  
Rwanda Plastic Industries (RPI)  DRS 300 : 2016  
v                 ©RSB2016 A ll rights reserved  
 
 Shalom Paints Ltd  
SIGMA PAI NTS 
The City of Kigali  
University of Rwanda — College of Education (UR — CE) 
University of Rwanda (UR) — College of Science and Technology (UR — CST)  
Rwanda  Standards Board (RSB) – Secretariat  
 DRS 300: 2016  
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 Epoxy resin for paints  — Specification  
1 Scope  
This Rwanda Standard prescribes the requirement s and methods of sampling and test for epoxy resin used in 
paint industry.  
2 Normative references  
The following referenced documents are indispensable for the application of this document. For dated 
references, only the edition cited applies. For undated references, the latest edition of the referenced 
document (includi ng any amendments) applies.  
ASTM A775M/A775M – 07b (2014) ,Standard Specification for Epoxy -Coated Steel Reinforcing Bars  
ASTM A934/A934M – 13,Standard Specification for Epoxy -Coated Prefabricated Steel Reinforcing Bars  
ISO 3 673-1: 1996,  Plastics — Epoxy resins — Part 1: Designation  
ISO 7142: 2007,  Binders for paints and varnishes — Epoxy resins — General methods of test  
3 Terms and definitions  
For the purposes of this standard, the following terms and definitions apply . 
3.1 
paint  
pigmented material, which when applied in a liquid form to a surface, forms after a time a dry adherent film. 
The following main types are recognized:  
a) oil paint - paint that contains drying oil or oil varnish as the basic vehicle ingredient;  
b) water paint (emulsion paint) - paint tha t contains a water emulsi on or dispersion as the vehicle; and  
c) paste paint - paint in which the pigment is sufficiently concentrated to permit a substantial reduction 
with vehicle before use.  
3.2 
epoxy resin  
synthetic resin containing epoxide groups and in which a final polymer is formed as a result of reaction taking 
place subst antially at the epoxide groups   
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 3.3 
ambient temperature  
temperature between 21ºC and 38 ºC  
3.4 
ageing  
change, if any, occurring in a coating on standing under defined conditions  at or near ambient temperature  
3.5 
epoxide equivalent  
mass of an epoxide compound, in grams, which contains one mole of epoxide group  
3.6 
rust 
coating of red or yellow oxides of iron produced when iron and steel is exposed to a humid atmosphere. Not to 
be confu sed with ‘White Rust’ which is a term loosely used to describe corrosion products of certain non -
ferrous metals  
3.7 
acid resistance  
resistance of paint, enamel or varnish film to acids. The term is of little value, unless it is referred to a standard 
of pe rformance under, specified conditions  
3.8 
latex paint  
paint based on pigment emulsion of synthetic resin  
3.9 
adhesion  
degree of attachment between a paint or varnish film and the underlying material which may be another film of 
paint or any other material, such as wood, metal, plaster, among others.  DRS 300: 2016  
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 3.10 
anti-condensation paint  
paint designed to minimize the effects of condensation of moisture under intermittently dry and humid 
conditions. Such a material normally has a matt textured finish and frequently contains cork or some other 
heat insulating materials as a filler  
3.11 
anti corrosive  
general term used to describe m aterial used for preventi ng corrosion  
3.12 
synthetic paint  
paints based on synthetic resin  
3.13 
barrier coat  
coating used to isolate a paint system from the surface to which it is applied in order to prevent chemical or 
physical interaction between them, t o prevent the paint solvent attacking the underlying paint or to prevent 
bleeding from underlying paint or material  
3.14 
binder  
non-volatile portion of the ‘Vehicle’ of a paint. It binds or cements the pigment particles together and the paint 
film as a who le to the material to which it is applied  
3.15 
bitty 
description applied to a paint or varnish containing bits of skin, gel, flocculated material or foreign particles, 
which project above the surface when the paint or varnish is applied in a manner appropr iate to its type and 
purpose. The term ‘Peppery’ is sometimes used when the bits are small and uniformly distributed. The term 
‘Seedy’ specifically denotes bits which have developed in a p aint or varnish during storage  
3.16 
bituminous p aints  
paints based e ssentially on bituminous ingredients   
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 3.17 
chalking  
phenomenon manifested in paint film by the presence of loose removable powder, evolved from the film itself 
at or just beneath the surface. Chalking may be detected by rubbing the film with the finger tip or other means  
3.18 
checking  
phenomenon manifested in paint film by slight breaks in the film that do not penetrate to the underlined 
surface. Different types of checking are gi ven below:  
a) irregular pattern type - Checking in which the breaks develop in the  surface of the film in no definite 
pattern.  
b) line type - Checking in which the breaks in the surface of the film are generally arranged in parallel lines, 
usually either horizontally or vertically over the surface of the film. These breaks often follow the  line of 
the brush marks.  
c) crow-foot type - checking in which the breaks in the surface of the film form in definite three prong 
pattern with the breaks running from a centre and forming an angle of 120 ºbetween the prongs  
3.19 
coat 
paint, varnish or lacquer  applied to a surface in a single application to form a properly distributed film when 
dry. A paint system usually consists of a number of coats separately applied in a predetermined order at 
suitable intervals to allow for drying. It is possible with cert ain types of material, to build -up paint systems 
ofadequate thickness and opacity by a more or less continuous process of application, namely wet on wet 
spraying. In this case no part of the system can be defined as a separate coat in the above sense. 
Following types are recognized : 
a) full coat, as thick a coat of paint, varnish or lacquer as can be applied in one operation (brush or spray) 
consistent with the production of a film of uniform appearance, satisfactory hardness, etc, when dry ; 
b) glaze coal - transl ucent or semi -transparent coating, sometimes coloured. It may be either an 
intermediate or the final coat of a paint system. It is frequently applied thinly with the object to modify 
but not obscure the ground colour;  
c) ground coat - coat of paint having goo d opacity which is applied before a glaze coat or stumble. The 
final colour effect when glazed is dependent on the mutual influence of the ground coat  and the glaze 
coat;  
d) guide coat - very thin coat of loosely bound paint applied over a continuous coating of surface or filler, 
prior to rubbing down. It is completely removed during the rubbing operations but, as it first disappears 
from the higher spots and ridges, it serves as a guide to the -operator in producing a smooth surface ; 
and DRS 300: 2016  
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 e) mist coat - It can be  of two types:  
i)  very thin coat applied by spraying, more particularly in connection with cellulose lacquers. In 
some cases it may form a ‘fogged’ co at or non -continuous film; and  
ii) ) thin coat of volatile thinners, with or without a small amount of lacquer, which is sometimes 
sprayed over a dry lacquer film to improve the smoothness and lustre.  
a) round coat - full coat of a heavy bodied paint or varnish.  
b) sharp coat -- coat of white lead in oil thinned liberally with turpentine or white spirit. A sharp coat used  
for treating new plaster following the trowel is frequently referred to as ‘sharp colour’.  
3.20 
coating  
liquid, liquefiable for mastic composition, that is converted to a solid protective, decorative or functional 
adherent film after application as a thin  layer  
3.21 
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  A condensation product of epichlorohydrin and bisphenol A in alkaline condition, which leads to 
formation of epoxy group containing resins. These resins shall have different molecular weight or epoxy 
equivalent weight depending on stoechiometric ratios of above mentioned reactants.  The manufacturer shall 
declare molecular distribution and average molecular weight.  
4.2.2  Depending upon the applications in paint system epoxy resins can be classified into three types based 
on average molecular weight or epoxy equivalent weight when det ermined through the method specified in 
Annex A, along with physical state of resin . 
Table 1 — Physical state of resin  
 
Types  Physical state  Average 
molecular weight  Epoxy equivalent 
weight  Test method  
Type A  Liquid  360-380 180-200  
 
 Type B  Low molecular weight, solid  
Grade 1   900 425-550  
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 Grade 2   1400  850-1000  Annex A  
Type C  High molecular weight, solid  
Grade 1   2900  1700 -2300  
Grade 2   3750  2400 -3500  
4.2 Specific requirements  
4.1 Epoxyresin shall comply with the requirements specified in Table 2. 
4.2 Keeping properties  
The material when stored in normal storage condition at the ambient temperature shall retain its property for at 
least 12 months from the date of manufacture as prescribed in Table 2.  
Table 2 — Requirement for epoxy resins  
S/N Characteristics  Type A  Type B  Type C  Test 
method  
Grade 1  Grade 2  Grade 1  Grade 2  
1 Colour (on ‘Gardner’ 
scale), Max  3 4 4 4 6 4.2.1   
2 Viscosity       4.2.2   
a As such at 25°  
±0.05°C ( cps )  8000 -
15000  A.1.1.1.1  - A.1.1.1.2  - A.1.1.1.3  - A.1.1.1.4  - 4.2.3   
b 40% in butyl 
carbitol at 25 
±0.5°C ( cps )  - 80-170 470-750 1600 -3400  4000 -11000  4.2.4   
c 50% in 1:1 
Mixture of 
O.Xylene/D.A.A 
at 25 ±0.5°C ( 
cps) - 100-150 - - - 4.2.5   
3 Softening point (ball 
and ring  - 60-70°C  90-100°C  117-127°C  130-145°C  4.2.6   
4 Epoxide equivalent 
g/mole  180-
200 425-550 850-1000  1700 -2300  2400 -3500  
5 Hydrolyzable chlorine 
content by mass, 
Max 0.5 0.2 0.2 0.2 0.2 
6 Relative density (at 
27ºC ±l 2ºC) 1.15-
1.20 - - - - ISO 7142  
 DRS 300: 2016  
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 5 Pack aging and marking  
5.1 Pack aging 
The material shall be pack aged in sound, clean and dry containers as agreed to between the manufacturer 
and the purchaser.  
5.2 Marking  
The containers shall be marked with the following information:  
a) name and type of the material;  
b) type and grade;  
c) mass of the material;  
d) month and year of manufacture;  
e) batch No. or lot No. in code or otherwise; and  
f) name of the manufacture and/or any recognized trade -mark.   
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 Annex  A 
(informative)  
 
Method of d etermination of epoxide  equivalent of epoxy compounds  
A.1 Principl e 
A.1.1  Method A 
Epoxide groups react with nascent hydrogen bromide produced by the action of a standard 0.1 mol/1solution 
of perchioric acid on tetraethyl ammonium bromide. The end -point is determined either 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. 
Thismethod is recomme nded for slow reactive epoxy resin.  
NOTE — Safety goggles and safety screen maybe used while carrying out tests through the above methods.  
A.2 Reagents  
A.2.1  Acetic Acid, Glacial  
A.2.2  Acetic Anhydride  
A.2.3  Suitable Solvent for Solution of the Sample  —for example, chloroform, dibutyl phthalate, 
chlorobenzene  
A.2.4  Potassium Hydrogen Phthalate  — Dry the potassium hydrogen phthalate for 2 h at 120 °C before 
use. 
A.2.5  Crystal Violet, Indicator Solution  — Dissolve 100 mg of crystal violet in 100 ml of ace tic acid.  
A.2.6  Perchloric Acid, 0.1 mol/1 Standard Solution  — To 8.5 mL ofa 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 thi s solution by titrating it against 200 mg of potassium hydrogen phthalate 
dissolved in 50 mL of acetic acid, using the crystal violet indicator solution ( see Note 1 ).  
A.2.7  Use 4 to 6 drops of the crystal violet indicator solution and continue the titrat ion until a stable green 
colour is obtained. Note the temperature, t s, of the solution of perch loric acid at the time of standardization 
(see Note 2). The concentration, C, in mol/1 of the standard perchloric acid solution, is given by the formula:  DRS 300: 2016  
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 Bibliography  
[1] IS 354: 1987, Methods of sampling and test for resins for paints: part 4, Special test methods for epoxy 
resins  
[2] IS 1070: 1992, Reagent Grade Water -- Specification (Third Revision)  
  DRS 300: 2016  
ICS 87.040  
 
 
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