CEN ISO/TR 23383:2020
(Main)Textiles and textile products - Smart (Intelligent) textiles - Definitions, categorisation, applications and standardization needs (ISO/TR 23383:2020)
Textiles and textile products - Smart (Intelligent) textiles - Definitions, categorisation, applications and standardization needs (ISO/TR 23383:2020)
This document provides definitions in the field of "smart" textiles and textile products as well as a categorization of different types of smart textiles. It describes briefly the current stage of development of these products and their application potential and gives indications on preferential standardization needs.
Textilien und textile Produkte - Smarte (Intelligente) Textilien - Definitionen, Klassifizierung, Anwendungen und Normungsbedarf (ISO/TR 23383:2020)
Dieses Dokument enthält Begriffe aus dem Bereich der „smarten“ Textilien und textilen Produkte, sowie eine Kategorisierung verschiedener Typen von smarten Textilien. In Kurzform werden der aktuelle Entwicklungsstand dieser Erzeugnisse und deren Anwendungsmöglichkeit beschrieben, und es werden Angaben zu vorrangigen Normungsbedarfen gemacht.
Textiles et produits textiles - Textiles intelligents - Définitions, catégorisation, applications et besoins de normalisation (ISO/TR 23383:2020)
Le présent document fournit des définitions dans le domaine des textiles et produits textiles «intelligents», ainsi qu'une catégorisation des différents types de textiles intelligents. Il décrit brièvement l'état actuel de développement de ces produits et leur application potentielle et fournit des indications sur les besoins de normalisation préférentiels.
Tekstilije in tekstilni izdelki - Inteligentne tekstilije - Definicije, kategorizacija, uporaba in standardizacijske potrebe (ISO/TR 23383:2020)
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
01-februar-2021
Nadomešča:
SIST-TP CEN/TR 16298:2012
Tekstilije in tekstilni izdelki - Inteligentne tekstilije - Definicije, kategorizacija,
uporaba in standardizacijske potrebe (ISO/TR 23383:2020)
Textiles and textile products - Smart (Intelligent) textiles - Definitions, categorisation,
applications and standardization needs (ISO/TR 23383:2020)
Textilien und textile Produkte - Intelligente Textilien - Definitionen, Klassifizierung,
Anwendungen und Normungsbedarf (ISO/TR 23383:2020)
Textiles et produits textiles - Textiles intelligents - Définitions, catégorisation, applications
et besoins de normalisation (ISO/TR 23383:2020)
Ta slovenski standard je istoveten z: CEN ISO/TR 23383:2020
ICS:
59.080.80 Inteligentne tekstilije Smart textiles
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
CEN ISO/TR 23383
TECHNICAL REPORT
RAPPORT TECHNIQUE
December 2020
TECHNISCHER BERICHT
ICS 01.040.59; 59.060.01 Supersedes CEN/TR 16298:2011
English Version
Textiles and textile products - Smart (Intelligent) textiles -
Definitions, categorisation, applications and
standardization needs (ISO/TR 23383:2020)
Textiles et produits textiles - Textiles intelligents - Textilien und textile Produkte - Intelligente Textilien -
Définitions, catégorisation, applications et besoins de Definitionen, Klassifizierung, Anwendungen und
normalisation (ISO/TR 23383:2020) Normungsbedarf (ISO/TR 23383:2020)
This Technical Report was approved by CEN on 6 September 2020. It has been drawn up by the Technical Committee CEN/TC
248.
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, Norway,
Poland, Portugal, Republic of North Macedonia, 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
© 2020 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN ISO/TR 23383:2020 E
worldwide for CEN national Members.
Contents Page
European foreword . 3
European foreword
This document (CEN ISO/TR 23383:2020) has been prepared by Technical Committee ISO/TC 38
"Textiles" in collaboration with Technical Committee CEN/TC 248 “Textiles and textile products” the
secretariat of which is held by BSI.
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 CEN/TR 16298:2011.
Endorsement notice
The text of ISO/TR 23383:2020 has been approved by CEN as CEN ISO/TR 23383:2020 without any
modification.
TECHNICAL ISO/TR
REPORT 23383
First edition
2020-11
Textiles and textile products — Smart
(Intelligent) textiles— Definitions,
categorisation, applications and
standardization needs
Textiles et produits textiles — Textiles intelligents — Définitions,
catégorisation, applications et besoins de normalisation
Reference number
ISO/TR 23383:2020(E)
©
ISO 2020
ISO/TR 23383:2020(E)
© ISO 2020
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
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Published in Switzerland
ii © ISO 2020 – All rights reserved
ISO/TR 23383:2020(E)
Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Functional and smart textile products . 2
4.1 Functional textile products . 2
4.1.1 General. 2
4.1.2 Electrically conductive textile products . 2
4.1.3 Thermally conductive textile products . 3
4.1.4 Thermally radiative (emissive) textile products . 3
4.1.5 Optically conductive textile products . 3
4.1.6 Fluorescent textile products . 3
4.1.7 Phosphorescent textile products . 4
4.1.8 Textile products releasing substances . 4
4.2 Smart (intelligent) textile products . 4
4.2.1 General. 4
4.2.2 Chromic textile products . 5
4.2.3 Phase change textile products . 5
4.2.4 Textile products with active ingredients inside the microcapsules . 6
4.2.5 Shape change (shape memory) textile products . 6
4.2.6 Super-absorbing polymers and gels . 6
4.2.7 Auxetic textile products . 7
4.2.8 Dilating and shear-thickening textile products . 7
4.2.9 Piezoelectric textile products . 7
4.2.10 Electroluminescent textile products . 7
4.2.11 Thermo-electric textile products . 8
4.2.12 Photovoltaic textile products . 8
4.2.13 Electrolytic textile products . 8
4.2.14 Capacitive textile products . 8
5 Smart textile systems . 9
5.1 Categories . 9
5.1.1 General. 9
5.1.2 Systems without energy or communication function (NoE-NoCom) .11
5.1.3 Systems with energy function, but without communication function
(E-NoCom).11
5.1.4 Systems with communication function but without energy function (noE-Com) 11
5.1.5 With energy and communication function (E-Com) .12
5.2 Examples of “Smart textile systems” and their functional analysis .12
5.2.1 Medical application: monitoring of health situation .12
5.2.2 Occupational safety application: work wear and protective clothing .13
5.2.3 Leisure and fashion application .14
5.2.4 Garment based on thermal control by phase change materials (PCM) .14
5.2.5 Heated garment, car seats, etc. for comfort or protection .14
5.2.6 Irradiation system for medical therapeutics .15
5.2.7 Geotextiles applications .16
6 Considerations for standardization .16
6.1 General .16
6.2 Verification of claimed performances .17
6.3 Innocuousness .17
6.4 Durability of properties .18
6.5 Product information .18
ISO/TR 23383:2020(E)
6.6 Environmental aspects .19
6.7 Examples of possible standardization of smart (intelligent) textile products and
systems .19
6.7.1 Smart (intelligent) textile products — Phase change materials (PCM) .19
6.7.2 Smart textile systems — Heating textile with temperature control .20
Bibliography .22
iv © ISO 2020 – All rights reserved
ISO/TR 23383:2020(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 38, Textiles, in collaboration with the
European Committee for Standardization (CEN) Technical Committee CEN/TC 248, Textiles and textile
products, in accordance with the Agreement on technical cooperation between ISO and CEN (Vienna
Agreement).
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.
ISO/TR 23383:2020(E)
Introduction
Terms like “smart textile” and “intelligent textile” mean different things to different people. However,
there is a common agreement that these are textiles or textile products that possess additional intrinsic
and functional properties not normally associated with traditional textiles.
Although adjectives such as “smart” or “intelligent” are mainly intended for marketing purposes, more
technically correct definitions will not prevent the use of this terminology by textile manufacturers or
by the general public. Nor will the unintended inclusion of “non-smart” products make products any
less safe or fit for purpose.
The standardization of smart textiles or smart textile products or systems is not straightforward
because it involves an overlap between the standardization of the “traditional” textile product, e.g.
a fire fighter's jacket, and the standardization of the additional intrinsic functional properties of the
“smart product”. This overlap can manifest itself in a number of areas, possibly including:
— Expertise: the knowledge and experience of standardization for the textile properties and for the
additional properties (temperature sensing, variable thermal insulation properties) can come from
different unrelated standardization groups. To take the above example, there should be input from
standardization groups working in the areas of textiles, medical devices and electric or electronic
devices.
— Testing: there is a need to test the additional functional properties to specific textile test standards
and vice versa. Again, with the same example, the electronic elements should be assessed for their
resistance to cleaning and the textile elements need to be tested for electrical safety.
— Unexpected and/or unintended synergies: these might result from the combination of technologies
in smart textiles and need be recognized and addressed by standardization, wherever possible. For
example, the presence of conductive fibres to incorporate a personal stereo into a smart raincoat might
increase the risk of the wearer suffering a lightning-strike in a thunderstorm. This is despite the fact
that neither rainwear nor personal stereos, when separate, need to be assessed against this risk.
— Legislation: Certain textile product groups, e.g. protective clothing, geotextiles or textile floor
coverings, are in addition subject to specific national and/ or regional legislation. It can be necessary
to simultaneously address the requirements of legislation covering more than one product category.
For example, a “classic” fire fighter's suit needs comply with the requirements for personal protective
equipment, whereas a “smart” fire fighter's suit with built-in electronic and ICT features should also
comply with the applicable provisions for electronic equipment and ICT. Conformity assessment
will therefore need to follow the conformity assessment schemes for all applicable legal provisions.
The purpose of this document is to identify the considerations that need to be addressed when writing
standards for smart textiles or applying existing standards to them. This information can be of use to:
— end-users, in determining whether a product has indeed been fully assessed;
— conformity assessment bodies, as a guide towards assessing products according to the appropriate
standards;
— specification writers, as a guide to writing new specific standards for smart textiles;
— manufacturers of smart textiles, to advise them on appropriate product testing and on suitable
ways to substantiate product claims;
— market surveillance authorities, to help in the assessment of product claims, product safety and
fitness for purpose.
The factual information in this document is available elsewhere in a more comprehensive form and each
individual item will inevitably be common knowledge to at least one group of readers. The aim of this
document is to guide readers through those areas, with which they are not familiar, and to direct them
vi © ISO 2020 – All rights reserved
ISO/TR 23383:2020(E)
towards further, more specialized reading. In accordance with ISO rules, this document is intended to
be reviewed regularly to keep it in line with technical and market evolutions.
TECHNICAL REPORT ISO/TR 23383:2020(E)
Textiles and textile products — Smart (Intelligent)
textiles— Definitions, categorisation, applications and
standardization needs
1 Scope
This document provides definitions in the field of “smart” textiles and textile products as well
as a categorization of different types of smart textiles. It describes briefly the current stage of
development of these products and their application potential and gives indications on preferential
standardization needs.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
textile fibre
unit of matter characterised by its flexibility, fineness and high ratio of length to maximum transverse
dimension, which render it suitable for textile applications
[SOURCE: Regulation EU 1007/2011, Article 3, 1. (b), (i)]
3.2
textile product
product made of textile fibres (3.1), yarns and/ or fabrics and intended to be used, as such or in
conjunction with other textile or non-textile elements
3.3
functional textile product
textile product to which a specific function is added by means of material, composition, construction
and/or finishing (applying additives, etc.)
3.4
smart textile product
intelligent textile product
interactive textile product
functional textile product (3.3) which interacts reversibly with its environment, or responds or adapts
to changes in the environment
Note 1 to entry: The term “smart textile” can refer to either a “smart textile product” or a “smart textile system”.
Only the context, in which the term is used, determines which one of the two is intended.
ISO/TR 23383:2020(E)
3.5
environment
surroundings
circumstances, objects, or conditions, which surround a textile material or textile product or the user of
that material or product
3.6
non-textile element
product which is not composed of textile fibres (3.1)
Note 1 to entry: Non-textile element(s) can include elements used for garment construction, for example slide
fastener(s), press stud(s), button(s), membranes, non-textile patches, prints, coatings, finishes.
Note 2 to entry: Non-textile element(s) can also include elements with functionalities listed in 4.1 and 4.2.
3.7
textile system
assemblage of textile product(s) and non-textile element(s)
3.8
smart textile system
textile-based system which exhibits an intended and exploitable response as a reaction either to
changes in its surroundings/environment or to an external signal/input
4 Functional and smart textile products
4.1 Functional textile products
4.1.1 General
Functional textile products can be components of smart textile systems and hence functional textile
products, which are relevant for these smart textile systems, are discussed here. This is illustrated by
the following examples.
EXAMPLE 1 A textile resistance heater
— Functional textile product: a conductive material forming the basis of a resistance heater in a textile system.
— Smart textile system: a textile resistance heater as (part of) a textile system, connected to an electrical power
supply which can only be switched on and off manually or a resistance heater as part of a textile system,
connected to an electrical power supply with a regulated power output and equipped with a temperature
sensor as to maintain a constant temperature around the heater.
EXAMPLE 2 Optical fibres
— Functional textile product: optical fibres used as part of a textile system
— Smart textile system: optical fibres as (part of) a textile system, connected to a light source which can only
be switched on and off manually or optical fibres as part of a textile system, connected to a light source with
a regulated power output and equipped with a sensor to adjust the illumination level to the amount of light
present due to other light sources in the surroundings of the textile system.
4.1.2 Electrically conductive textile products
Electrically conductive textile product conducts an electrical current or supply an electric field to a
device. Electrical conduction is the movement of electrically charged particles through an electrical
2 © ISO 2020 – All rights reserved
ISO/TR 23383:2020(E)
conductor, called an electric current. The charge transport can result as a response to an electric field
or as a result of a concentration gradient in carrier density, i.e. by diffusion.
NOTE A material is considered to have a "good electrical conductivity" if it has a specific conductivity
2 4
(resistivity) of > 10 S/m (<10 Ω·cm). A material is considered to have "ohmic behaviour" if its resistance
follows Ohms law, a fundamental law of electricity, stating that the voltage at the terminals of an ideal resistor
1)
is proportional to the current in the resistor . The materials with the highest specific conductivity are metals.
Some polymers and ceramics can also show ohmic behaviour, e.g. intrinsically conductive polymers (e.g. doped
polyaniline) or indium tin oxide (ITO).
4.1.3 Thermally conductive textile products
Thermally conductive textile products conduct heat. The transfer of thermal energy in a substance is
due to a temperature gradient, i.e. from a region of higher temperature to a region of lower temperature,
acting to equalize temperature differences.
Metals have thermal conductivities above approximately 20 W/(m·K) and are considered to be very
good thermal conductors. Their thermal conductivity increases with their electrical conductivity.
There are also non-metallic elements and compounds that are (very) good thermal conductors (e.g.
carbon and boron nitride).
Applications in smart textile systems can be as a heat sink, e.g. for cooling electronic components.
4.1.4 Thermally radiative (emissive) textile products
Thermally radiative (emissive) textile products radiate heat, i.e. they emit electromagnetic radiation in
the infrared range of 750 nm to 100 µm from their surface due to their temperature.
Thermal radiation (emission) can be utilized in the form of a resistance heater, where the resistance of
a conductor is used to heat the conductor to a sufficiently high temperature to generate heat radiation
or as a heat exchanger, e.g. a pipe with hot air or hot water flowing through it.
Applications in smart textile products are as thermal heaters, as described in 4.1.1.
4.1.5 Optically conductive textile products
Optically conductive textile products transport (visible) light, i.e. electromagnetic radiation in the
range of 400 nm to 750 nm.
Optical fibres from glass or plastic keep the light in their core by total internal reflection, i.e. the fibre
acts as a waveguide. Optical fibres are widely used in fibre-optic communications, which permits
transmission over longer distances and at higher bandwidths (data rates) than other forms of
communications. Fibres are used instead of metal wires because signals travel along them with less
loss, and they are also immune to electromagnetic interference.
Fibres are also used for illumination, and are wrapped in bundles so they can be used to carry
images, thus allowing viewing in tight spaces. Specially designed fibres are used for a variety of other
applications, including sensors and fibre lasers.
4.1.6 Fluorescent textile products
Fluorescence is the molecular absorption of a photon, followed almost instantaneously by the emission
of a less energetic photon. As the emitted photon is of lower energy than the absorbed photon, the
emitted light will be of longer wavelength than the absorbed light, which allows, for example, to turn
UV radiation into visible light.
1) www .electropedia.or g IEV ref 131–15–08.
ISO/TR 23383:2020(E)
Fluorescence is used in high visibility clothing for safety purposes. Fluorescent textile products are
available in a variety of colours from red to blue-violet. A variety of organic and inorganic materials
show fluorescence.
4.1.7 Phosphorescent textile products
Phosphorescence is the molecular absorption of a photon, resulting in the formation of an excited state,
followed by the emission of a less energetic photon. Since the emitted photon is of lower energy than
the absorbed photon, the emitted light will be of longer wavelength. The lifetime of the excited state
in phosphorescent materials can be very long, in the order of hours. This means that once activated,
phosphorescent materials will continue to emit light for hours without any external power supply. This
makes them suitable for emergency lighting in the case of power interruptions or for watches, toys,
apparel, giving a "glow in the dark" effect.
Examples of phosphorescent materials are doped (mixed) sulphides (ZnS, (Cd, Zn)S, (Ca, Sr)S) or doped
(mixed) oxides (SrAl O ) but can also be organic molecules.
2 4
4.1.8 Textile products releasing substances
These textile products release substances at a molecular level under the influence of an external
stimulus. The substances used for this purpose are pharmaceuticals, cosmetics, fragrances, etc. They
are bonded to the textile structure by micro-encapsulation or by surface bonding.
[1]
NOTE Some of these textiles are referred to as cosmetotextiles (see CEN/TR 15917 ).
The micro-encapsulation technique makes use of small capsules, in which the substance to be released
is enclosed. When the shell of these capsules is pierced due to an external stimulus, the substance is
released. The different stimuli that can cause piercing of the shell include mechanical force, heat, pH
and contact with water.
The surface bonding technique makes use of substances (loosely) bonded to the surface of the textile
material and released during the use of this material. The nature of the bonding and the surroundings
of the material determines the release rate.
4.2 Smart (intelligent) textile products
4.2.1 General
In this subclause, examples (non-exhaustive) for different smart (intelligent) textile products are
described. The described textile products (see 4.2.2 to 4.2.14) can be used on their own or in combination
with other (non)smart textile products or used in textile systems. The latter are described in Clause 5.
NOTE Some of the smart functionalities can also be achieved by non-textile elements. Therefore, we will be
referring to textile products to clearly make the distinction.
Table 1 provides an overview of the most common stimulus-response pairs and the corresponding
effect materials or structures can exhibit.
4 © ISO 2020 – All rights reserved
ISO/TR 23383:2020(E)
Table 1 — Overview of most common stimulus-response effects (adapted from the final report
[2]
of the FP6 project Clevertex )
Stimulus Response
Optical Mechanical Chemical Electrical Thermal
Optical Photochromism Photovoltaic/
photoelectric
effect
Mechanical Piezochromic Dilatant, Controlled Piezo- Friction
thixotropic, release electricity
auxetic,
controlled release
Chemical Chemiluminescence, Shape memory, Controlled Chemical Exo/endotherm
Solvatochromism, super-absorbing release gradient reactions
Halochromisms polymers, causing charge
sol/hydrogel, separation –
controlled release Galvanic cell
Electrical Electrochromism, Inverse piezo- Electrolysis Joule/coulombic
Electroluminescence, electricity, heating
Electro-optic electrostriction,
Peltier effect
electro-osmosis,
shape memory
Thermal Thermochromism, Shape memory, Controlled Seebeck effect, Phase change
Thermo-opacity controlled release release Pyroelectric
Magnetic Shape memory
Magnetrostriction
4.2.2 Chromic textile products
Chromic material is the general term referring to materials whose absorption, transmission and/or
reflection of light changes due to an external stimulus. The result is a different colour impression.
Chromic materials can be classified depending on the external induction stimulus, e.g. light
(photochromic), heat (thermochromic), pressure (piezochromic), enzymes (biochromic), electricity
(electrochromic). It goes beyond the scope of this report to list all possible chromic effects or to discuss
them in detail.
One commercial application of a thermochromic textile product is baby clothing which shows a change
in colour when the baby has developed a fever. Other applications envisioned for safety clothing are the
use of chromic textile products for indicating exposure to chemicals or radiation.
4.2.3 Phase change textile products
A phase change material (PCM) is a substance which is capable of storing and releasing large amounts
of energy in the form of latent heat, at a specified temperature range (range of phase transformation)
during which the material changes phase or state (from solid to liquid or from liquid to solid). This
energy (heat) is absorbed or released when the material changes from solid to liquid (or the other way
around), thus buffering any external temperature change by evoking a phase transition in the material.
Classic PCMs are water, hydrated salt complexes and saturated hydrocarbons (where the length of the
chain determines the melting point). Depending on the nature of the phase change, e.g. when formation
of a liquid phase is involved, micro-encapsulation can be required. The choice of material or composite
depends on the temperature to be buffered.
The most common method today to produce phase change textile products is by coating or impregnating
fibres or fabrics with a polymeric binder containing micro-encapsulated PCMs. Alternatively, micro-
ISO/TR 23383:2020(E)
encapsulated PCMs can be incorporated into fibres during the fibre spinning or filling of hollow fibres.
They can also be laminated as a PCM containing polymeric film onto a textile structure.
Space suits and gloves were the first application of phase change materials (PCM), but nowadays
PCMs are also used for consumer products to improve the thermal comfort of active-wear garments
and clothing textiles. During a sports activity, the thermal stress is mainly due to the disequilibrium
between the heat produced by the human body during an effort, and the heat released into the
environment. When PCMs are encapsulated on underwear during the same activity, a larger amount of
the human heat will be released to the environment.
4.2.4 Textile products with active ingredients inside the microcapsules
Content of the micro-capsules can react on a stimulus from the environment without being released.
One example is PCM materials (see 4.2.3).
Another example are polyols inside a micro-capsule, which can take up perspiration. There is an
endothermal reaction between the polyols and the water, which results in a cooling effect.
NOTE Some of these textiles are referred to as cosmetotextiles (see CEN/TR 15917).
4.2.5 Shape change (shape memory) textile products
These materials change in shape, size or internal structure upon an external stimulus, e.g. temperature,
UV light, moisture, magnetic field, pH value. The shape change can have a one-way or a two-way effect.
A one-way material has a preformed structure, which returns in a non-reversible way to its original,
not-preformed state after receiving an external stimulus.
A two-way material or composite can be cycled between two different preformed states by receiving
opposing external stimuli, e.g. a higher and lower temperature.
Shape memory materials can be:
— polymers with a combination of permanent physical or chemical cross-links, integrated into a
mobile matrix, which is able to store mechanical deformation energy until recovery is activated by
an external stimulus;
— metal alloys switching between two different crystal structures upon a thermal impulse, e.g.
Nitinol, or
— composites of shape-memory-materials and materials providing an elastically restoring force in
one unit (e.g. artificial muscles).
Shape memory materials can be implemented in textile systems in the form of yarns, i.e. in the bulk of
the textile structure or as a coating on a fabric, e.g. creating a membrane. Applications can be textile
systems adjusting their shape, e.g. a garment reducing its length when exposed to heat; or a membrane
adjusting its porosity, e.g. to adjust the water vapour transmission rate.
4.2.6 Super-absorbing polymers and gels
Super-absorbing polymers and gels absorb and retain extremely large amounts of liquid relative to
their own mass resulting in strong swelling and gel formation. Water absorbing polymers (hydrogels)
absorb aqueous solutions through hydrogen bonding with water molecules. The ability to absorb water
depends on the presence of ions in the water, being 500 times its weight (30 to 60 times its volume) for
distilled or deionised water, but only 50 times its weight for a 0,9 % saline solution.
The total absorbency and swelling capacity are controlled by the type and degree of cross-linking in
the polymer. A low-density cross-linked polymer has a higher absorbent capacity and a softer and more
cohesive gel is formed. High cross-link density polymers exhibit lower absorption capacity, but the gel
strength is firmer, maintaining its shape under low pressure.
6 © ISO 2020 – All rights reserved
ISO/TR 23383:2020(E)
Examples of the use of super-absorbing polymers are hygiene products, blockage of water penetration
in underground power communication cables, horticultural water retention agents, spill and waste
control, artificial snow for motion picture and stage production and filtration.
4.2.7 Auxetic textile products
Auxetic materials or composites harden and laterally expand upon elongation. This phenomenon is
caused by the macro-structure or micro-structure of the material and not by its chemical composition.
Such materials have a so-called negative Poisson ratio.
Some auxetic textile products contain on a micro-scale both temporary, relatively weak bonds (e.g.
hydrogen bonds), which can be broken and restored (slipping from one to the other) under a low shear
force and stable bonds which, under a high shear force, counters the full load of the force, resulting in a
"stiff" behaviour.
Other auxetic textile products are based on the use of materials with diverging properties, e.g. a textile
yarn comprising a thicker, elastic cord entwined with a thinner, stiffer cord. When tensioned, the
system changes to the thin, stiff cord being entwined by the thicker, elastic cord and the total diameter
increases as compared to the relaxed state.
Auxetic textile products are intended for improved energy absorption and fracture resistance.
Examples of auxetic textile applications are blast resistance, window covering, military tents, and
hurricane defence. Examples of auxetic foam materials are found in sound and shock absorption,
medical engineering, filtration of biological fluids and process engineering.
4.2.8 Dilating and shear-thickening textile products
These materials show an increase in viscosity with increasing shear rate, i.e. they become hard upon
impact and remain soft under low force movement.
A dilatant effect occurs when closely packed particles are combined with enough liquid to fill the gaps
between them. At low flow velocities, the liquid acts as a lubricant, and the dilatant flows easily. At
higher flow velocities, the liquid is unable to fill the gaps created between particles, friction strongly
increases, resulting in a sudden increase in viscosity.
Applications in textiles are found in protective clothing against mechanical impact, e.g. body armour,
and in traction control. An example is a soft silicone coating on a fabric, which hardens under impact,
thus damping the force of the blow.
4.2.9 Piezoelectric textile products
The piezo-electric effect consists of a separation of electrical charges across a material in response to
an applied mechanical deformation. This effect can also be inversed, i.e. a mechanical deformation is
generated in response to an applied electric field.
Applications of the piezo-electric effect are found in insulating materials having a non-centrosymmetric
crystal lattice (e.g. quartz, PZT, PVDF). In order to utilize the charge separation by mechanical
deformation or to realize the mechanical deformation by applying an electric field, the piezo-electric
material needs to be positioned between two electrodes. For polycrystalline materials to exhibit the
piezoelectric or inverse piezoelectric effect, the individual crystallites need to be aligned, which is done
by applying a high electric field at elevated temperatures.
Piezoelectric materials can be used to develop textile products for strain or acceleration sensing as well
as for energy production utilizing mechanical deformation (e.g. in shoes).
4.2.10 Electroluminescent textile products
This refers to textile products emitting light in response to an electric current passing through
them or to a strong electric field being applied to them. In these structures, the electroluminescent
ISO/TR 23383:2020(E)
layer are sandwiched between two electrodes, the top one being transparent for transmission of the
emitted light.
For the electroluminescent layer most commonly inorganic or organic semiconductors (thin film or
powder) are used, together with a dopant (additive) to define the colour, or inorganic materials such as
ZnS, doped with Cu, Ag, or Mn.
Electroluminescent textile products can operate at low voltage and low current. They can be used to
provide lighted displays on apparel or canvasses for leisure or advertising purposes.
4.2.11 Thermo-electric textile products
These materials generate an electric field when a thermal gradient is applied. The material needs to
show a good electrical conductivity but a poor thermal conductivity in the direction of the thermal
gradient.
In these structures, the thermo-electric material are sandwiched between textile electrodes and a good
heat transfer needs to be ensured at the external surfaces.
Thermo-electric textile products applications are power
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