CEN/TR 17509:2020

SLOVENSKI STANDARD
01-oktober-2020
Materiali, pridobljeni iz izrabljenih avtomobilskih gum - Granulirana guma -
Ugotavljanje deleža tekstilnih vlaken z vizualnim indeksom (kvalitativna metoda)
Materials obtained from End-of-Life Tyres - Granulated rubber - Determination of textile
fiber content by visual index (qualitative method)
Materialien aus Altreifen - Gummigranulat - Bestimmung des Textilfasergehalts durch
visuellen Index (qualitative Methode)
Matériaux produits à partir de pneus usagés non réutilisables (PUNR) - Granulats de
caoutchouc - Détermination de la teneur en fibres textiles par indice visuel (méthode
qualitative)
Ta slovenski standard je istoveten z: CEN/TR 17509:2020
ICS:
13.030.50 Recikliranje Recycling
83.160.01 Avtomobilske pnevmatike na Tyres in general
splošno
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

CEN/TR 17509
TECHNICAL REPORT
RAPPORT TECHNIQUE
July 2020
TECHNISCHER BERICHT
ICS 13.160
English Version
Materials obtained from End-of-Life Tyres - Granulated
rubber - Determination of textile fiber content by visual
index (qualitative method)
Matériaux produits à partir de pneus usagés non Materialien aus Altreifen - Gummigranulat -
réutilisables (PUNR) - Granulats de caoutchouc - Bestimmung des Textilfasergehalts durch visuellen
Détermination de la teneur en fibres textiles par indice Index (qualitative Methode)
visuel (méthode qualitative)
This Technical Report was approved by CEN on 22 June 2020. It has been drawn up by the Technical Committee CEN/TC 366.

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/TR 17509:2020 E
worldwide for CEN national Members.

Contents Page
European foreword . 3
Introduction . 4
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 5
4 Principle . 5
5 Apparatus . 6
5.1 Splitter or sample separator . 6
5.2 Tray . 6
5.3 Template . 6
5.4 Scale . 7
6 Preparation of sampling plan and laboratory sample . 7
7 Procedure. 7
7.1 Sample spreading . 7
7.2 Grid counting . 9
7.3 Number of tests per sample . 10
8 Expression of results . 10
9 Preliminary studies . 10
10 Experimental results. 17
10.1 Grinder A (Spanish experience). 17
10.2 Grinder B (Spanish experience). 21
11 Further developments . 25
Bibliography . 26

European foreword
This document (CEN/TR 17509:2020) has been prepared by Technical Committee CEN/TC 366
“Materials obtained from End-of-Life Tyres (ELT)”, the secretariat of which is held by UNI.
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.
Introduction
During the production of materials obtained from end-of-life tires (ELTs), maintenance of quality levels
is based on the control of characteristics such as particle size distribution, steel and textile content.
Particularly important is this last parameter. Its determination can be based on the method described in
the EN 14243 series, but this test exhibits difficulties when the textile content is high and part of the fibres
are bound to the rubber.
For this reason, for granulates there is a need to define an alternative approach capable of characterizing
the content of textile fibres, free and bounded. This characterization is especially useful as a quick control
that detects quality deviations during the production process and for the acceptance of the materials by
consumers.
1 Scope
The purpose of this document is to provide information about a procedure based on the determination
of a visual index correlated with the content of textile fibres, which are free and bounded to the rubber,
of granulates. This approach is currently used by Spanish grinders in order to control the efficiency of
their processes and is effective for granulates with particle sizes the bottom limit of which is more than
0,5 mm, and upper limit less than 10 mm.
NOTE Part of this document is also the presentation of a study carried by Valoriza Servicios Medioambientales
and Geneus Canarias S.L.
A test procedure for the determination of a visual index of the content of the textile fibre of a granulate
sample, which is free and bounded to the rubber, from the ELT’s processing is described in
UNE 53936:2015 EX: Materials produced from end of life tyres. Rubber granulates.
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.
EN 14243-1:2019, Materials obtained from end of life tyres - Part 1: General definitions related to the
methods for determining their dimension(s) and impurities
3 Terms and definitions
For the purposes of this document, terms and definitions given in EN 14243-1:2019 and the following
apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at http://www.electropedia.org/
— ISO Online browsing platform: available at http://www.iso.org/obp
3.1
bounded textile
textile fraction on the granulate, that is bounded to the rubber and that cannot be separated without
pulling rubber particles with it
3.2
visual index
conventional value, expressed in %, that correlates with the content of textile in a sample of granulate
and is obtained through a mechanical device and the visual control of an operator
Note 1 to entry: 0 % index means absence of textile, 100 % a presence of textile in all the parts of the device of
control.
4 Principle
The determination of textile fibres, which are free and bounded to the rubber, of an ELT sample of
granulates, is based on the calculation of a visual index.
The underlying method is based on the recount of textile particles detectable to the naked eye in a sample
distributed over the surface of a tray. To make the calculation easy, a grid template is placed over each
sample.
The visual index is the ratio between the number of cells in which one textile is detected to the naked eye
with respect to the total number of cells on the grid template.
5 Apparatus
5.1 Splitter or sample separator
The most used one is the riffle splitter: the sample separator shall contain at least 16 slots, located
alternately so they send the material to two different subsamples. The width of the slots shall be at least
three times the upper nominal size of the material to be divided in order to avoid the bridge effect.
5.2 Tray
Square or rectangular tray, rigid with flat surface and an area of (1 500 ± 50) cm , of any material,
provided that it does not bound or interact with the rubber. See Figure 1.

Figure 1 — Example of tray
A tray of 30 cm x 50 cm that matches with a 375 grids template is recommended.
5.3 Template
Square or rectangular template of geometry equivalent to the surface of the tray, divided on 2 cm x 2 cm
cells and that do not prevent the proper visualization of the sample. See Figure 2.

Figure 2 — Example of template
5.4 Scale
Scale capable of measuring the mass of the sample with an estimate within 0,1 g.
6 Preparation of sampling plan and laboratory sample
The base is a representative sample obtained from moving material in production or from storage
material on a big-bag. The sample is divided with a splitter until obtaining a mass of 500 g ± 5 g.
7 Procedure
7.1 Sample spreading
The sample to test is placed on the tray and then the material is evenly distributed across its surface, see
Figure 3.
Figure 3 — Sample placed on the tray
To allow the various free and bound textile particles come to the surface, the tray shall be hit against the
work surface five times, as illustrated in Figures 4 and 5.
Figure 4 — Example of the hitting process

Figure 5 — Sample spreaded on the tray
Hereafter the template mentioned in 5.3 is placed on it, see Figure 6.
Figure 6 — Template placed on the tray
7.2 Grid counting
A counting of the cells where free or bound textile is visually detected is performed (see Figures 7 and 8),
and the value obtained is written down.

Figure 7 — Grid counting process
Figure 8 — Example of the cells where free or bound textile is visually detected
7.3 Number of tests per sample
Once performed the recount, the template is withdrawn. The tray is emptied and the sample is poured on
it again. The operating procedure is repeated according to 7.1 and 7.2. The results are written down. The
procedure is repeated until obtaining three values of the same sample.
8 Expression of results
The visual index comes from the equation:
Visual index = 𝑁𝑁 /𝑁𝑁 x 100 [1]
𝑓𝑓
where
𝑁𝑁 average value obtained from the three measurement of the grid number in which is
𝑓𝑓
detected the presence of textile fibre
N  total number of cells on the template
The value rounded upward is established as the result of the visual index.
9 Preliminary studies
Some preliminary tests have been carried out in order to study the effect of the following parameters:
— Cell size;
— Number of tests per sample;
— Tray area/ Sample thickness;
— Textile content.
In the preliminary studies, several samples with known quantity of free and bounded textile particles
were prepared. This way, it could be compared the results obtained in the different conditions respect to
the reference value in each case, see Figure 9.
a) Free textile particles b) Bounded textile particles
Figure 9 — Examples of free and bounded textile particles
A summary of tests performed by SIGNUS, are described below.
— Effect of the cell size:
First of all, it is important
...