Adhesives - Terms and definitions

This European Standard defines terms used in the adhesive industry and terms relating to adhesives in those industries that use adhesives.

Klebstoffe - Benennungen und Definitionen

Diese Norm definiert Begriffe, die in der Klebstoffindustrie verwendet werden, sowie Begriffe, die sich in der klebstoffverarbeitenden Industrie auf Klebstoffe beziehen.

Adhésifs - Termes et définitions

La présente Norme européenne définit les termes utilisés dans l’industrie des adhésifs ainsi que ceux y
afférant et qui sont usités dans les industries utilisatrices d’adhésifs.

Lepila – Izrazi in definicije

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EN 923:2006
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SIST EN 923:2006
SIST EN 2243-2:1998
SIST EN 923:1999
Lepila – Izrazi in definicije
Adhesives - Terms and definitions
Klebstoffe - Benennungen und Definitionen
Adhésifs - Termes et définitions
Ta slovenski standard je istoveten z: EN 923:2005
01.040.83 Gumarska industrija in Rubber and plastics
industrija polimernih industries (Vocabularies)
materialov (Slovarji)
83.180 Lepila Adhesives
SIST EN 923:2006 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN 923:2006

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SIST EN 923:2006
EN 923
October 2005
ICS 83.180 Supersedes EN 923:1998
English Version
Adhesives - Terms and definitions
Adhésifs - Termes et définitions Klebstoffe - Benennungen und Definitionen
This European Standard was approved by CEN on 12 September 2005.
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 Central Secretariat 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 Central Secretariat has the same status as the official
CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,
Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia,
Slovenia, Spain, Sweden, Switzerland and United Kingdom.
Management Centre: rue de Stassart, 36  B-1050 Brussels
© 2005 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 923:2005: E
worldwide for CEN national Members.

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SIST EN 923:2006
EN 923:2005 (E)
Contents Page
Foreword .3
1 Scope .5
2 Terms and definitions.5
2.1 Adhesives.5

2.2 Functional adhesive components.9
2.3 Chemical base products.12
2.4 Adhesive properties.20
2.5 Material and material treatment .24
2.6 Bonding .26
2.7 Bond properties .32
Annex A (informative) Adhesives.36
Annex B (informative) Adhesives joints .38


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SIST EN 923:2006
EN 923:2005 (E)
This European Standard (EN 923:2005) has been prepared by Technical Committee CEN/TC 193
“Adhesives”, the secretariat of which is held by AENOR.
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 April 2006, and conflicting national standards shall be withdrawn at the
latest by April 2006.
This European Standard supersedes EN 923:1998.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: Austria, Belgium, Cyprus, Czech Republic,
Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland
and United Kingdom.

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SIST EN 923:2006
EN 923:2005 (E)
This European Standard comprises terms peculiar to, or in general use in, the adhesive and adhesive
processing industry.
The terms defined have been classified so that, as far as possible, related concepts (adhesives, functional
adhesive components, chemical base products, adherents, adhesives properties, bonding, and bond
properties) are grouped together. All definitions are numbered and an alphabetical index which includes all
terms is provided at the end of this European Standard.
The numbering of the individual definitions is the same in all three versions (English, French and German) of
this European Standard. Consequently this European Standard can be used as a dictionary, combined with
one or both of the other versions as an aid for translation of terms into French or German, as a source of
information about related concepts in the adhesive industry or to provide a term for a concept.
In order to find:
a) the definition of a term; look up the term in the alphabetical index at the end of this European Standard.
The index will refer to the number in this European Standard. The definition, the term and any synonyms
appear by the number;
b) information about related terms; look up the term in the alphabetical index to find its number in this
European Standard. When the term has been located in this European Standard, the related concepts
can be found in the same subdivision;
c) the translation of a term into the French or German language; look up the number of this term in this
European Standard and locate the translation of the term and the definition under the same number in the
standard of the foreign version.

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SIST EN 923:2006
EN 923:2005 (E)
1 Scope
This European Standard defines terms used in the adhesive industry and terms relating to adhesives in those
industries that use adhesives.
2 Terms and definitions
2.1 Adhesives
non-metallic substance capable of joining materials by surface bonding (adhesion), and the bond possessing
adequate internal strength (cohesion)
NOTE Many adhesives names refer to their main functional components;
 the physical nature of the adhesive.
Table A.1 lists main binders, temperature and mode of setting of these adhesives and the number of parts that have to be
mixed before use. Some other names refer to
 the method of application, or
 mode of setting.
Furthermore adhesives are named according to points of less significance:
 field of application (e.g. footwear adhesive, construction adhesive, packaging adhesive),
 material to bond (e.g. paper adhesive, wood adhesive, wall paper adhesive, rubber adhesive),
 place of application (e.g. in situ adhesive),
 speed of setting (e.g. instant adhesive),
 bond properties (e.g. structural adhesive),
 shape (e.g. powder adhesive, pearl glue, table glue for solid glue, adhesive film for shaped adhesive, or stick
adhesive for stick shaped adhesives), or
 aspect (e.g. white glue).
water-borne adhesive; aqueous adhesive
adhesive in which the solvent, or the continuous phase is water
aqueous adhesive specifically designed for bonding of wood and other porous substrates
NOTE A glue can be based on a natural product like protein or synthetic resins (UF, PF or PVAC, see 2.3.51, 2.3.52
and 2.3.30 respectively)
paste adhesive
adhesive of a non-stringy, highly viscous nature

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SIST EN 923:2006
EN 923:2005 (E)
NOTE Paste adhesives based on starch or cellulose ethers are usually applied for paper bonding (e.g. paper bags or
wall paper), based on synthetic polymers for bonding floor coverings.
dispersion adhesive
adhesive consisting of a stable dispersion of a polymer in a liquid continuous phase, usually water
NOTE Dispersion adhesives containing an elastomer as polymer conventionally are often termed "latex".
emulsion adhesive
adhesive consisting of a stable emulsion of a liquid hydrophobic resin in water
solvent-borne adhesive; solution adhesive, solvent-based adhesive
adhesive in which the binder is dissolved in a volatile organic solvent
NOTE In practice solvents used for solvent-borne adhesives have boiling points below 170 °C at 101,3 kPa and a
vapour pressure greater than 50 Pa at 20 °C and, if flammable, a flash point below 55 °C.
solvent free adhesive
adhesive that is substantially free from organic solvents (see 2.1.7)
NOTE "Substantially free" means that organic solvents have neither been added in the basic elements of an
adhesive nor during its process of manufacture out of these basic elements. "Low solvent adhesives" contain at most 5 %
of solvents based on total weight of the adhesive.
plastisol adhesive
adhesive material formed by the dispersion of a polymer in a plasticizer such that, when the dispersion is
heated, the polymer dissolves irreversibly in the plasticizer to form a solution that solidifies on cooling
toughened adhesive
adhesive which by virtue of its physical structure discourages propagation of cracks
NOTE The toughening can be achieved, for example, by the creation of a discrete elastomeric phase within the
adhesive matrix.
spray adhesive
adhesive that is projected in small particles by means of a pressure medium
gap-filling adhesive
adhesive designed for filling wider gaps between uneven surfaces
NOTE For high strength load-bearing purposes, e.g. in the car industry, the adhesive will provide satisfactory bond
strength in bond-lines up to 1 mm in thickness. For the construction industry, high solid adhesives designed for use
between uneven surfaces and to bond satisfactorily in gaps up to 6 mm are used.
adhesive material, used to fill gaps where movement can occur in service and which, when set, has elastic
NOTE The term "sealant" is also used for a material filling a void against the ingress or egress of a fluid under

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SIST EN 923:2006
EN 923:2005 (E)
film adhesive
adhesive in film form, with or without a carrier
NOTE Film adhesives set usually by means of heat under pressure.
foaming adhesive
adhesive designed to foam in situ, after application, in order to provide extensive gap-filling properties
unsupported film adhesive
adhesive supplied in sheet, film or web, without an incorporated carrier
supported film adhesive
adhesive supplied in sheet or film form with an incorporated carrier that remains in the bond when the
adhesive is applied and used
NOTE The carrier can be woven or non-woven material consisting of organic or inorganic fibres.

adhesive tape
flexible backing or carrier coated with a pressure-sensitive, remoistable, or heat activatable adhesive
transfer tape
carrier coated with a pressure-sensitive adhesive which, when detached from the substrate, permits the
carrier to be removed leaving only the adhesive
double coated adhesive tape; double sided adhesive tape
tape where the adhesive is applied on both sides of the carrier
multiple-layer adhesive
film adhesive, usually supported with a different adhesive composition on each side
NOTE Multiple-layer adhesives are designed to bond dissimilar materials.

encapsulated adhesive
adhesive in which particles or droplets of the adhesive or an adhesive component are enclosed in a protective
film (microcapsules) usually to prevent cross-linking until the film is destroyed by suitable means
one-way stick adhesive
adhesive that is applied to only one of the adherends
separate application adhesive
adhesive consisting of different components which are applied separately to adherends
NOTE Pressing together the components initiates a chemical reaction curing the bond-line.
two way stick adhesive, double spread adhesive
adhesive that is applied to both adherends

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SIST EN 923:2006
EN 923:2005 (E)
one part adhesive
adhesive ready for use
NOTE A one-part adhesive can require the addition of water or the presence of ambient moisture for setting.
two part adhesive
adhesive that consist of two separate reactive components that are mixed before use
multi-part adhesive
adhesive that consists of two or more separate reactive components that are mixed before use
contact adhesive
adhesive that is applied to both adherends and when allowed to become apparently dry will instantly develop
a firm bond when a firm but not sustained pressure is applied
NOTE "apparently dry" means that the adhesive coats are "dry to touch" at some stage in the evaporation of volatile
hot melt adhesive
adhesive that is applied in the molten state and forms a bond on cooling to a solid state
heat activated adhesive
adhesive pre-applied to the adherends that is rendered tacky prior to use by application of heat and forms a
bond on cooling under pressure
heat sealing adhesive
adhesive pre-applied to one or both adherends that is activated by the application of heat and forms a bond
on cooling
NOTE Heat-sealing adhesives are commonly used in the packaging industry.
solvent activated adhesive
adhesive pre-applied to an adherend that is rendered tacky immediately prior to use by the application of
pressure sensitive adhesive
adhesive which in a dry state is permanently tacky at room temperature and adheres readily to surfaces under
light and brief pressure
NOTE Pressure-sensitive adhesives are used among other things for the manufacture of pressure sensitive tapes.
cold setting adhesive (cold glue deprecated)
adhesive that sets without the application of heat
hot setting adhesive
adhesive that sets only with the application of heat


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SIST EN 923:2006
EN 923:2005 (E)
reaction adhesive, reactive adhesive
adhesive that sets by a chemical reaction of its components and/or the action of external agents
cold curing adhesive
adhesive that cures without the application of heat
hot curing adhesive
adhesive that cures only with the application of heat
self curing adhesive
adhesive that cures, after application, under specified conditions
anaerobic adhesive
adhesive that cures in absence of oxygen, curing being inhibited by the presence of oxygen and catalysed by
metal ions
moisture curing adhesive
adhesive that cures by reaction of water from the air or from an adherend
conductive adhesive
adhesive especially designed to either avoid the accumulation of an electrical charge or to conduct an
electrical current
adhesive batch
quantity of a particular adhesive (or component of an adhesive) manufactured in a single location at a defined,
limited time and under uniform conditions
NOTE "Lot" is a commonly used commercial term. A lot can consist of less or more than one batch.
2.2 Functional adhesive components
component of an adhesive that is primarily responsible for the adhesion and cohesion
chemical compound, usually of low molecular mass, that can be converted into a polymer by combining with
itself or with other chemical compounds
substance composed of molecules characterized by the multiple repetition of one or more species of atoms or
groups of atoms (constitutional units) linked to each other in amounts sufficient to provide a set of properties
that do not markedly vary with the addition or removal of one or a few of the constitutional units
NOTE The nature of these constitutional units, their order and the average number per molecule influence the
physical and mechanical properties of the polymer.
polymer derived from more than one species of monomer

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SIST EN 923:2006
EN 923:2005 (E)
macromolecular material which returns rapidly to approximately its initial dimensions and shape after
substantial deformation by a weak stress and release of the stress at room temperature
solid, semi solid or pseudosolid organic material that has an indefinite and often high relative molecular mass,
exhibits a tendency to flow when subjected to stress, usually has a softening or melting range, and usually
fractures conchoidally
NOTE 1 In a broader sense, the term is used to designate any polymer that is basic material for plastics. Bitumen,
pitches and waxes are excluded by convention.
NOTE 2 Some resins may be part of a reaction adhesive (see 2.1.37).
synthetic resin
resin derived from a synthetic monomer
thermoplastic resin, thermoplast
polymer or copolymer capable of being softened by heating and hardened by cooling
NOTE Softening and hardening are repeatable. Many thermoplastic materials can become thermoset by appropriate
treatment to induce crosslinking, e.g. by the addition of a suitable chemical crosslinking agent or by irradiation.
thermosetting resin, thermoset
monomer, polymer or copolymer, which when cured, changes into a substantially infusible and insoluble
NOTE The setting of a thermosetting resin undergoes three different stages: the "A-stage" at which the material is
still fusible and still soluble. The intermediate pseudo-stable "B-stage" at which it is fusible and partially soluble. The "B-
stage" is converted to the final crosslinked, insoluble and infusible "C-stage" by application of heat and, usually, pressure.
crosslinking agent
substance that causes, promotes or regulates the formation of intermolecular, covalent or ionic bonds
between polymer chains resulting in a three dimensional molecular network
NOTE Crosslinking can occur either between polymer chains or by reaction of simple functional molecules (e.g. two
part polyurethane or epoxy adhesives). Crosslinking can also be produced by radiation or oxidation. The terms "hardener"
and "curing agent" are often used synonymously with crosslinking agent.
adhesion promotor; coupling agent
substance used in small proportions to increase the adhesion to specific substrates
substance used in small proportions to increase the reaction rate of a chemical system (reactants, plus
substance used in small proportion, that augments the rate of a chemical reaction, and in theory remains
unchanged chemically at the end of the reaction


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SIST EN 923:2006
EN 923:2005 (E)
substance used in small proportions to suppress a chemical reaction
substance used in small proportions to reduce the reaction rate of a chemical system
substance used to retard deterioration caused by oxidation
flexibilizer; internal plasticizer
co-reactant which, when incorporated into a polymer confers improved flexibility and resilience to the polymer
NOTE A flexibilizer provides to the adhesive film a greater extension at break, a lower modulus and a lower
temperature at which it becomes brittle. A flexibilizer is not extractable and will not migrate from the adhesive film.
plasticizer; external plasticizer
non-reactive substance incorporated into an adhesive to improve flexibility and resilience of its bond.
NOTE A plasticizer provides to the adhesive film a greater extension at break, a lower modulus and a lower
temperature at which it becomes brittle. A plasticizer can be soluble and can migrate from the adhesive film.
liquid or mixture of liquids that are used in the manufacture of adhesives to dissolve or to dilute the binder
without chemical change
NOTE Solvents are used to control the consistency and character of the adhesive and can regulate application
diluent (thinner, deprecated)
liquid whose sole function is to reduce the concentration of solids and viscosity of an adhesive

reactive diluent
low-viscosity liquid added to a high-viscosity solvent-free adhesive which reacts chemically with the adhesive
during setting
NOTE A reactive diluent is usually mono-functional and reduces the viscosity of the adhesive with acceptable
changes in other properties.
relatively inert solid material added to a plastic or an adhesive to modify strength, permanence, working
properties or other quality
NOTE 1 Two classes of fillers are used:
 chemically inert fillers, e.g. china clay or woodflour;
 "reinforcing fillers" like silicates, carbon black, fibrous materials or aluminium powder that markedly enhance the per-
formance of a polymer.
NOTE 2 A filler only used to reduce cost is termed “extender”. An extender can be a liquid.

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SIST EN 923:2006
EN 923:2005 (E)
part of an adhesive that surrounds or engulfs embedded filler or reinforcing particles and filaments
ingredient which, when added to an adhesive, changes its properties
NOTE The term modifier includes fillers, diluents, plasticizers and tackifiers.
substance used in the formulation of some plastics or adhesives to assist in maintaining the properties of the
material or of the adhesive and its bonds at or near their initial values during storage and processing and
under service conditions
NOTE Special stabilizers are used to prevent or slow down undesirable effects such as coagulation, excessive
reactivity, absorption by adherends or destruction of adherends.
emulsifier; emulsifying agent; dispersant
surface-active substance that promotes and maintains the dispersion of two incomplete miscible liquids or a
solid and a liquid by reducing the interfacial tension between the two phases
substance intended to enhance the tack or the tack range of an adhesive coat
2.3 Chemical base products
soluble silicate
silicate obtained by melting a purified silica with an alkali salt
hydraulic cement
inorganic adhesive material that sets and hardens by chemical interaction with water and that is capable of
doing so under water
NOTE 1 Hydraulic cements set chemically by "hydration" thus forming compounds with strength-producing properties.
There are several types of hydraulic cements:
 “Portland cement“, produced by pulverizing partially fused "clinker" consisting primarily of hydrated calcium silicates,
and usually containing calcium sulfate in any hydration state (anhydrite, gypsum, hemihydrate);
 “natural cement“, produced by calcining a naturally occurring argillaceouse limestone at a temperature below the
sintering point and then grinding to a fine powder;
 “slag cement“, consisting mostly of an intimate and uniform blend of granulated blast-furnace slag and hydrated lime
in which the slag constituent is more than a specified minimum percentage. Blast-furnace slag is the non-metallic
product consisting essentially of silicates and aluminosilicates of calcium and other bases that is developed in a
molten condition simultaneously with iron in a blast furnace;
 “Portland-Pozzolan cement“, consisting of an intimate and uniform blend of Portland cement or Portland blast-furnace
slag cement and fine pozzolan, in which the amount of the pozzolan constituent is within specified limits. Pozzolan is
a siliceous and aluminous material which in itself possesses little or no cementitious value but which will, in finily
divided form and in the presence of moisture, chemically react with calcium hydroxide at ordinary temperatures to
form compounds possessing cementitious properties.

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SIST EN 923:2006
EN 923:2005 (E)
NOTE 2 "Concrete" is composite material that consists essentially of a binder (e.g. hydrated cement and water) within
which are embedded particles of fragments or aggregates.
NOTE 3 The term "cement" is also used as a synonym for organic adhesives but its use is strongly deprecated.
natural product having the repeating linkage -NH-CO-
NOTE Some examples are:
 Soya bean protein is obtained from soya bean seeds. When compounded with other reactants it is used as an
adhesive, mostly in plywood.
 "Casein" is protein precipitated from skimmed milk by the action of rennet or acid. When compounded with other
reactants it is used as an adhesive for wood and packaging applications.
 "Collagen" is produced from collagenous animal materials like skin, bone and connective tissue.
 "Gelatine" is a soluble protein derived from collagen.
 "Animal glue" is an impure protein obtained by hydrolysis of collagenous materials by various methods and is
predominantly used for bonding of wood and other porous substrates.
vegetable carbohydrate occurring in the granular form in certain plants and corresponding to a polymer
composed almost exclusively of anhydroalpha-D-glucose groups
starch ether
modified starch in which the hydroxyl groups of the starch have been totally or partially etherified
starch ester
modified starch in which the hydroxyl groups of the starch have been totally or partially esterified
modified starch prepared from starch by heat treatment in the dry state with or without the addition of small
quantities of chemical agents
NOTE Dextrin is used in certain water-borne adhesives.
cellulose esters
products of esterification of certain of the hydroxyl groups of the cellulose macromolecule with organic or
mineral acids
NOTE Examples of cellulose esters are cellulose acetate, cellulose acetobutyrate, cellulose acetopropionate,
cellulose nitrate. Cellulose esters are soluble in organic solvents such as esters or ketones, and thus form the basis of
some solvent-borne adhesives.
cellulose ethers
products of etherification of certain of the hydroxyl groups of the cellulose macromolecule
NOTE Examples of cellulose ethers are carboxymethyl cellulose, methyl cellulose, hydroxyethyl- and hydroxypropyl
cellulose. Cellulose ethers are soluble in, or solubilized by water and simple alcohols and find use as the basis of water
soluble adhesives for paper and as thickening agents in water-borne adhesives.

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SIST EN 923:2006
EN 923:2005 (E)
water-soluble vegetable resin
NOTE Gums are dried exudations of plants or modified vegetable products.
 "Gum arabic" is the dried exudation from the stem and the branches of Acacia senegal Willdenow and other species
of acacia.
 "Gum tragacanth" is the dried mucilaginous exudation from Astragalus gummifer and other species of astragalus
(leguminosae), and which is partly soluble in water. Gum tragacanth is used as a modifier and stabilizer in water (or
occasionally alcohol) borne adhesives.
 "Cellulose gum" is a water-soluble cellulose derivative used as a substitute for gum arabic.
 "British gum" is a special type of dextrin normally used in textile sizing.
 "Mucilage" is a solution of a gum in water.
dammar resin
is obtained from species of Shorea, Hopea, and Balnocarpus
NOTE Dammar resin is soluble in certain organic solvents and used as a tackifier and modifier of pressure-sensitive
terpene resin
pale thermoplastic polyterpene hydrocarbons obtained by the acid catalysed polymerization of bicyclic
monoterpene ß-pinene (or occasionally α-pinene) products of the distillation of sulphate-cellulose-turpentine
NOTE Terpene resin is principally used in adhesives as a tackifier. Hydrogenated and polymerized grades are
tall resin
essentially consisting of abietic acid and its isomers obtained from pine trees by the sulphate-cellulose-
rosin; colophony
resin essentially consisting of abietic acid and its isomers obtained as a residue in the distillation of crude
turpentine from the sap of pine tree ("gum rosin") or from an extract of the stumps and other parts of the tree

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