ISO 21701:2019
(Main)Textiles —Test method for accelerated hydrolysis of textile materials and biodegradation under controlled composting conditions of the resulting hydrolysate
Textiles —Test method for accelerated hydrolysis of textile materials and biodegradation under controlled composting conditions of the resulting hydrolysate
This document specifies a test method for the determination of the biodegradability of the hydrolysate of textile materials obtained after accelerated hydrolysis under controlled composting conditions by measurement of the amount of evolved carbon dioxide with a gas chromatography. This test method can be applied to petroleum-based man-made biodegradable textile materials which are manufactured from polyethylene terephthalate succinate, polycaprolactone, polypropylene carbonate, polybuthylene succinate or copolymer using them.
Textiles — Méthode d’essai pour hydrolyse accélérée des matières textiles et la biodégradation dans des conditions de compostage contrôlées de l'hydrolysat résultant
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INTERNATIONAL ISO
STANDARD 21701
First edition
2019-09
Textiles — Test method for accelerated
hydrolysis of textile materials and
biodegradation under controlled
composting conditions of the resulting
hydrolysate
Textiles — Méthode d’essai pour hydrolyse accélérée des matières
textiles et la biodégradation dans des conditions de compostage
contrôlées de l'hydrolysates résultant
Reference number
©
ISO 2019
© ISO 2019
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ii © ISO 2019 – All rights reserved
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 2
5 Reference material . 3
6 Apparatus . 3
7 Test procedure . 4
7.1 Preparation of test material . 4
7.2 Preparation of the inoculum . 4
7.3 Accelerated hydrolysis test (abiotic test) . 4
7.4 Biodegradation test (biotic test) of hydrolysate . 4
7.5 Gas chromatographic analysis . 5
8 Calculation and expression of results . 5
8.1 Amount of carbon dioxide in grams . 5
8.2 Percentage of biodegradation . 7
8.3 Validity of results . 7
9 Test report . 7
Annex A (informative) Example of apparatus . 8
Annex B (informative) Example of accelerated hydrolysis test results . 9
Bibliography .10
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
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ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
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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).
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.org/iso/foreword .html.
This document was prepared by Technical Committee ISO/TC 38, Textiles.
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.
iv © ISO 2019 – All rights reserved
Introduction
Textile fibres can be classified into natural fibres and man-made fibres according to ISO/TR 11827. Some
of man-made fibres manufactured from organic materials are biodegradable and can be divided into
three major categories in relation to their origin, i.e. natural material base, biology base and petroleum
base. The representative bio-based, man-made biodegradable fibre is polylactide and petroleum-
based, man-made biodegradable fibres are manufactured from polyethylene terephthalate succinate,
polycaprolactone, polypropylene carbonate, polybuthylene succinate or copolymer using them.
The biodegradation of petroleum-based fibres is relatively slow compared to biology-based or natural
fibres due to the chemical structure. In addition, the rate of biodegradation of textile materials such
as fibres and yarns can also be affected negatively by high molecular weight, degree of crystallinity
and orientation occurred during the spinning. Although some standards refer to the instrument
analysis, such as gas chromatograph or infrared analysis, the process and calculation method are not
standardized. Therefore, it is difficult to determine the biodegradation of petroleum-based textile
materials using the existing standards available for natural fibres, biology-based fibres or plastic
materials used for packaging.
To overcome these difficulties, the new test method is proposed by a combination of accelerated
hydrolysis and biodegradation using instrument analysis for analysis of evolved carbon dioxide.
Under the composting of textile materials both mechanisms, abiotic and biotic processes, operate
together and the microorganisms eventually remove the hydrolysate in a synergistic process. It is
difficult and time consuming to reproduce this in the laboratory. For convenience, the accelerated
hydrolysis, which is an abiotic process, should be carried out followed by biodegradation subsequently.
The rate and extent of molecular weight loss is measured as indicative of losses in physical properties
from accelerated hydrolysis and then the biodegradability of hydrolysate is estimated by direct
measurement of evolved carbon dioxide with a gas chromatograph.
INTERNATIONAL STANDARD ISO 21701:2019(E)
Textiles — Test method for accelerated hydrolysis of
textile materials and biodegradation under controlled
composting conditions of the resulting hydrolysate
1 Scope
This document specifies a test method for the determination of the biodegradability of the hydrolysate
of textile materials obtained after accelerated hydrolysis under controlled composting conditions by
measurement of the amount of evolved carbon dioxide with a gas chromatography.
This test method can be applied to petroleum-based man-made biodegradable textile materials
which are manufactured from polyethylene terephthalate succinate, polycaprolactone, polypropylene
carbonate, polybuthylene succinate or copolymer using them.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 1628-1, Plastics — Determination of the viscosity of polymers in dilute solution using capillary
viscometers — Part 1: General principles
ISO 13885-1, Binders for paints and varnishes — Gel permeation chromatography (GPC) — Part 1:
Tetrahydrofuran (THF) as eluent
ISO 14855-1, Determination of the ultimate aerobic biodegradability of plastic materials under controlled
composting conditions — Method by analysis of evolved carbon dioxide — Part 1: General method
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
compost
organic soil conditioner obtained by biodegradation of a mixture principally consisting of various
vegetable residues, occasionally with other organic material and having a limited mineral content
3.2
composting
aerobic process designed to produce compost
3.3
total dry solids
amount of solids obtained by taking a known volume of test material or compost and drying at about to
constant mass
3.4
volatile solids
amount of solids obtained by subtracting the residue of a known volume of test material or compost
after incineration at about from the total dry solids of the same sample
Note 1 to entry: The volatile-solids content is an indication of the amount of organic matter present.
3.5
abiotic process
process without the action of living organisms
3.6
biotic process
process through the actions of living organisms
3.7
hydrolysis
degradation identified as resulting from hydrolytic cleavage of macromolecules
3.8
accelerated hydrolysis
hydrolysis under high temperature and humidity
3.9
hydrolysate
product of hydrolysis
3.10
theoretical amount of evolved carbon dioxide
ThCO
maximum theoretical amount of carbon dioxide evolved after completely oxidizing a chemical
compound, calculated from the molecular formula and expressed as milligrams of carbon dioxide
evolved per milligram or gram of test compound
3.11
maximum level of biodegradation
degree of biodegradation, measured as a percentage, of a chemical compound or organic matter in a
test, above which no further biodegradation takes place during the test
3.12
plateau phase
time, measured in days, from the end of the biodegradation phase until the end of the test
4 Principle
WARNING — Any claim on biodegradation or (industrial) compostability of the textile material
is not allowed and considered misleading. For claims on biodegradation under controlled
composting conditions, testing shall be carried out in accordance with ISO 14855-1.
The test method determines the ultimate biodegradability of test material after accelerated hydrolysis
under conditions simulating an intensive aerobic composting process. It aims to determine the ultimate
biodegradability of the hydrolysate by using a small-scale reactor. The degradation rate is periodically
measured by determining the amount of the evolved carbon dioxide using gas chromatography.
Firstly, the test material is hydrolysed under the constant temperature and humidity until the
substantial loss of molecular weight in order to initiate the biodegradation process shortly.
During the aerobic biodegradati
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