SIST EN 14621:2006

SLOVENSKI STANDARD
01-marec-2006
Tekstilije – Multifilamentne preje – Metode preskušanja teksturiranih in gladkih
filamentnih prej
Textiles - Multifilament yarns - Methods of test for textured or non-textured filament yarns
Textilien - Multifilamentgarne - Prüfverfahren für texturierte und nicht texturierte
Multifilamentgarne
Textiles - Multifilaments - Méthodes d'essai des multifilaments texturés ou non texturés
Ta slovenski standard je istoveten z: EN 14621:2005
ICS:
59.080.20 Preje Yarns
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN 14621
NORME EUROPÉENNE
EUROPÄISCHE NORM
December 2005
ICS 59.080.20
English Version
Textiles - Multifilament yarns - Methods of test for textured or
non-textured filament yarns
Textiles - Multifilaments - Méthodes d'essais pour la frisure Textilien - Multifilamentgarne - Prüfverfahren für texurierte
des fils multifilaments texturés et le retrait thermique des und nicht texturierte Multifilamentgarne
fils plats et textures
This European Standard was approved by CEN on 26 October 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
versions.
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.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
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 14621:2005: E
worldwide for CEN national Members.

Contents
page
Foreword .3
1 Scope.4
2 Normative references .4
3 Terms and definitions.4
4 Test methods.5
5 Test report .14
Annex A (informative) Calculation of the length of yarn to be reeled.16
Bibliography.19
Foreword
This European Standard (EN 14621:2005) has been prepared by the Technical Committee CEN /TC 248
"Textiles and Textile Products", the secretariat of which is held by BSI.
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 June 2006, and conflicting national standards shall be
withdrawn at the latest by June 2006.
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.
1 Scope
This European Standard specifies test methods for quality control of textured and non-textured
multifilament synthetic yarns. It includes the following test methods:
 determination of the crimp contraction - textured multifilament yarn with linear density up to
500 dtex;
 determination of the hot air shrinkage - for non-textured and textured multifilament yarns;
 determination of the boiling water shrinkage - for non-textured and textured multifilament yarns.
2 Normative references
The following referenced documents are indispensable for the application of this European Standard. For
dated references, only the edition cited applies. For undated references, the latest edition of the
referenced document (including any amendments) applies.
EN ISO 139, Textiles — Standard atmospheres for conditioning and testing (ISO 139:2005)
3 Terms and definitions
For the purposes of this European Standard, the following terms and definitions apply.
3.1
crimp contraction
contraction of a textured filament yarn resulting from the development of crimp, expressed as a
percentage of its original length, with the lengths of the contracted and straightened yarns measured
under specified tensions
3.2
thermal shrinkage
decrease in length of a textured or non-textured filament yarn as a result of a thermal treatment (boiling
water or hot air), expressed as a percentage of its original length
3.3
linear density
mass per unit length of a multifilament yarn as defined in EN ISO 2060
3.4
tension
tensile force applied to the specimen, generally related to its linear density
3.5
pre-tension
tension applied to a specimen at the beginning of certain tests
3.6
straightened length
length of the specimen measured under a high tensile force, which straightens the skein without
stretching
3.7
contracted length of textured yarn
length of the specimen measured under a low tensile force after a specified recovery time has elapsed
3.8
package
form of presentation of the multifilament yarn, e.g. spool, cheese, cone, bobbin etc.
3.9
multifilament yarn
yarn composed of several filaments
4 Test methods
4.1 Determination of the crimp contraction
4.1.1 Principle
The crimp of a specimen of a textured filament yarn in the form of a skein of known nominal linear density
is developed by treatment with hot air while the specimen is subjected to a low tensile force. After
reconditioning, the straightened length of the skein is measured under a high tensile force. After a
specified recovery time, the contracted length of the skein, shortened by the effect of the yarn crimp, is
measured under the low tensile force.
Crimp contraction is calculated as the difference between the two length values related to the straightened
length.
4.1.2 Apparatus
4.1.2.1 Reel
A reel with a circumference of (1 000 ± 2,5) mm is used for winding the yarn skeins. The reel shall be
fitted with a device to provide the specified tensile force per unit linear density to the material being
wound on with the maximum possible accuracy and to maintain the separation between a number of
skeins wound at the same time.
4.1.2.2 Automatic testing device
A suitable testing device (see Figure 1) uses a loading apparatus, which extends the skein at a speed of
(1 000 ± 10) mm/min until the pre-set tensile force is reached at which the yarn crimp is pulled out, and
which determines the straightened skein length related to that tensile force.
NOTE The speed of the loading apparatus may be reduced e.g. in case of less extensible textured yarns, for
example to 250 mm/min, provided that this is clearly stated in the test report. Only test results obtained with identical
speeds may be compared.
The same apparatus determines in a second measurement the contracted length of the skein under a low
tensile force provided by a pre-tension weight attached to the skein or a hook-shaped pre-tension weight
attached to the skein.
Resolution of the length measurement is 0,05 mm or better.
A number of skeins are arranged in a holder, with the skeins being tested in succession. The holder can
be removed from the automatic testing device.

Key
1 Specimen holder
2 Specimen
3 Pre-tension weight (e.g. an S-shaped hook)
4 Loading apparatus and length measuring system
5 Force measuring system
Figure 1 — Automatic testing device
4.1.2.3 Oven with forced ventilation
The oven shall be suitable for a heat treatment of the test specimens arranged in the holder of the
automatic testing device at 120 °C. The temperature variation from the set value shall not exceed ± 4 °C
in the immediate vicinity of the specimens.
The utilizable space shall have a height of at least 600 mm and suitable width and depth to accommodate
the holder of the automatic testing device in an upright position, so that the skeins can hang perfectly.
The oven shall be operated with forced air circulation.
4.1.3 Conditioning and preparation of the test specimens
Take off at least 500 m from the packages representing the laboratory samples before preparing the test
specimens.
Prior to testing, the specimens are exposed for at least 24 h to the standard atmosphere according to
EN ISO 139.
To permit the use of the same linear density related tensile forces for yarns of different linear density, a
skein is produced having a linear density of about 2 500 dtex (250 tex) by winding a corresponding length
of yarn onto a reel. While the yarn is being reeled, a tensile force per unit linear density of 2 cN/tex ± 10 %
shall be maintained as uniformly as possible. (See Annex A for the calculation of the length of yarn to be
reeled.)
The two yarn ends shall then be tied together, but in such a way that stretching of the yarn is avoided.
When suspending the skeins from the specimen holder, the knots are placed at the suspension hooks.
Throughout the sampling and conditioning procedures, particular care should be taken that any stress
applied to the specimens in the course of handling does not exceed the tensile force applied during
reeling.
4.1.4 Procedure
After the skein is removed from the winding reel, it is suspended from the holder of the automatic testing
device, and a tension weight of 2,5 cN (e.g. an S-shaped hook) is attached to the skein to produce the
required tensile (force per unit linear density of 0,01 cN/tex) which remains on the skein throughout the
whole testing procedure.
Following this, the holder with the skeins is placed into the oven preheated to a temperature of
(120 ± 4) °C, with its forced air circulation in operation, and is kept there for a period of
10 min ± 20 s to develop the crimp.
Placing the holder into the oven shall be carried out within a time of 5 s to 10 s to minimize the
temperature drop in the oven.
When the crimp development time has elapsed, the holder with the specimens is removed from the oven
and exposed again to the standard atmosphere for 24 h for reconditioning and relaxation.
NOTE 1 The period of conditioning the specimens after reeling as well as after the heat treatment may be
reduced, e.g. to 30 min, provided that this is clearly stated in the test report. Only test results obtained with identical
conditioning periods may be compared.
NOTE 2 Polypropylene or polyethylene may be tested under different conditions of time and temperature,
provided that this is clearly stated in the test report. Only test results obtained under identical test conditions may be
compared.
To determine the straightened length L , the holder with the specimens is placed into the automatic
testing device tester. Thereafter, starting with the first specimen in the holder, the loading apparatus
gradually extends the skein until a tensile force of 500 cN (i.e. 2 cN/tex ± 5 %) is reached. This force is
maintained for (10 ± 1) s, and after this, the straightened length L is measured.
Following the determination of the straightened length, the loading apparatus travels in the opposite
direction to release the tensile force on the skein.
The specimen holder now turns to the next position, and the loading apparatus subjects the next skein to
the same tensile force.
After all specimens in the holder have been tested, and after a relaxation period of 10 min ± 20 s has
elapsed, the contracted length L of each skein under the pre-tension weight of 2,5 cN is measured by the
same loading apparatus.
4.1.5 Calculation and expression of the results
The crimp contraction, CC, expressed in percent, is calculated from the following equation:
L −L
0 1
CC = 100 × (%)
L
where
L is the straightened length;
L is the contracted length.
4.2 Determination of the hot air shrinkage
4.2.1 Principle
Skeins of known nominal linear density are subjected to a low tensile force and treated with hot air at a
specified temperature for a specified time. The skein length is measured under a specified tensile force
suitable to straighten the skein before and after the heat treatment. Shrinkage is calculated as the
difference between the two length values related to the length before the heat treatment.
4.2.2 Apparatus
4.2.2.1 Reel
A reel with a circumference of (1 000 ± 2,5) mm is used for winding the yarn skeins. The reel shall be
fitted with a device to provide the specified tensile force per unit linear density to the material being
wound on with the maximum possible accuracy and to maintain the separation between a number of
skeins wound at the same time.
4.2.2.2 Automatic testing device
A suitable testing device uses a loading apparatus, which extends the skein with a speed of
(1000 ± 10) mm/min for textured yarn or (250 ± 10) mm/min for non-textured yarn until the preset tensile
force is reached at which the skein is straightened.
The device determines the initial length of the skein at this tensile force.
The same apparatus determines in a second measurement the length of the skein in the shrunken state
(after treatment of the skein in the oven) under a low tensile force provided by a pre-tension weight
attached to the skein.
Resolution of the length measurement is 0,05 mm or better.
A number of skeins are arranged in a holder, with the skeins being tested in succession. The holder can
be removed from the automatic testing device.
4.2.2.3 Oven with forced ventilation
The utilizable space shall have:
 a height of at least 600 mm and suitable width and depth to accommodate the holder of the
automatic testing device in an upright position, so that the skeins can hang perfectly;
 a thermometer (e.g. thermocouple) to measure and record the hot air temperature in the vicinity of
the test specimens;
 an applied temperature accuracy of ± 3 °C.
Preferably, the oven has a temperature control to allow preheating the oven to a higher temperature level prior to
placing the holder with the specimens into the oven, and to reduce the temperature to the required value:
190 °C, after the holder has been put in. In this manner a temperature drop below the required value can
be avoided.
The temperature variation from the set value shall n
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