ISO 5688:2024

Textiles - Synthetic filament yarns - Test methods for crimp properties of textured yarns

This document specifies a test method for crimp properties of synthetic textured filament yarns. Two treatment methods for crimp development are provided: - Method A: Hot air method, and - Method B: Hot water method.

Textiles — Fils de filaments synthétiques — Méthodes d'essai des propriétés de frisure des fils texturés

General Information

• Status: Published
• Publication Date: 25-Jan-2024
• ICS: 59.080.20 - Yarns
• Technical Committee: ISO/TC 38/SC 23 - Fibres and yarns
• Drafting Committee: ISO/TC 38/SC 23 - Fibres and yarns
• Current Stage: 6060 - International Standard published
• Start Date: 26-Jan-2024
• Due Date: 23-Jun-2024
• Completion Date: 26-Jan-2024

Overview

ISO 5688:2024 - Textiles - Synthetic filament yarns - Test methods for crimp properties of textured yarns defines standardized laboratory procedures to determine the crimp behaviour of synthetic textured filament yarns. The standard specifies two approved crimp-development treatments: Method A (hot air) and Method B (hot water), and describes specimen preparation, conditioning, measurement, calculation of results and reporting requirements.

Key topics and technical requirements

• Scope: Test method for crimp properties (contraction, modulus, stability) of textured synthetic filament yarns.
• Crimp development methods:
  • Method A - Hot air: development of crimp using a ventilated oven (temperature range and stability requirements provided).
  • Method B - Hot water: immersion in hot water (use distilled or grade 3 water with non‑ionic surfactant 0.1 g/L unless otherwise agreed).
• Specimen preparation:
  • Skein winding reel with specified circumference (1 000 ± 2.5 mm), controlled tension and turn count.
  • Tension for reeling calculated by FP = P × T, where P for textured yarns = (0.20 ± 0.02) cN/dtex.
  • Recommended set linear densities for skeins (examples: ≤200 dtex → 2 500 dtex; 200–400 dtex → 5 000 dtex; >400 dtex → 10 000 dtex).
• Apparatus requirements:
  • Test specimen holder (vertical frame, hooks/clamps, >600 mm height).
  • Length measuring device accurate to ±0.1 mm and tension application devices avoiding >10% overshoot.
  • Ventilated oven (30 °C–130 °C capability, temperature variation ±2 °C near specimens).
  • Hot water container capable of maintaining 100 °C ±3 °C around specimens.
• Conditioning and sampling:
  • Standard atmosphere per ISO 139.
  • Sampling guidance: avoid testing earlier than 5 days after processing; stress‑decay effects largely negligible after 7 days.
• Results and calculations:
  • Express crimp contraction, crimp modulus, and crimp stability according to the methods and formulas in the standard.
• Precision and reporting: includes precision data and required test report items.

Applications and users

ISO 5688:2024 is intended for:

• Textile testing laboratories performing routine quality control of textured filament yarns.
• Yarn and filament manufacturers validating crimp characteristics during product development and acceptance.
• R&D teams assessing process changes (texturising, heat setting) and performance effects.
• Conformance and certification bodies requiring harmonized test data for specification compliance.

Practical benefits include reproducible crimp measurements for product specification, quality acceptance, process optimisation, and comparative benchmarking across suppliers.

Related standards

• ISO 139 - Standard atmospheres for conditioning and testing (referenced for environmental control).
• ISO 10132 - Definitions for textured filament yarns.
• ISO 3696 - Water for analytical laboratory use (grade 3 water).
• ISO 3534‑1 - Statistical vocabulary related to test precision and reporting.

Standards Content (Sample)

International
Standard
ISO 5688
First edition
Textiles — Synthetic filament
2024-01
yarns — Test methods for crimp
properties of textured yarns
Textiles — Fils de filaments synthétiques — Méthodes d'essai des
propriétés de frisure des fils texturés
Reference number
© ISO 2024
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 on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
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Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii
Contents  Page
Foreword .iv
1  Scope . 1
2  Normative references . 1
3  Terms and definitions . 1
4  Principle . 1
5  Reagents . 2
6  Apparatus . 2
7  Sampling . 4
8  Standard atmosphere for conditioning and testing . 4
9  Preparation of test specimen . 4
9.1 Tension for reeling.4
9.2 Turns of reel .5
9.3 Reeling .5
9.4 Number of tests .5
9.5 Conditioning.6
10  Test procedure . 6
10.1 Crimp development .6
10.1.1 Method A — Hot air method .6
10.1.2 Method B — Hot water method .6
10.2 Measuring lengths .7
11  Calculation and expression of results . 8
11.1 Crimp contraction . .8
11.2 Crimp modulus .8
11.3 Crimp stability .9
11.4 Test results .9
12  Precision . 9
13  Test report . 9
Annex A (informative)  Precision experiments . 10
Bibliography .12

iii
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
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This document was prepared by Technical Committee ISO/TC 38, Textiles, Subcommittee SC 23, Fibres and
yarns.
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
International Standard ISO 5688:2024(en)
Textiles — Synthetic filament yarns — Test methods for crimp
properties of textured yarns
1  Scope
This document specifies a test method for crimp properties of synthetic textured filament yarns.
Two treatment methods for crimp development are provided:
— Method A: Hot air method, and
— Method B: Hot water method.
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 139, Textiles — Standard atmospheres for conditioning and testing
ISO 3534-1, Statistics — Vocabulary and symbols — Part 1: General statistical terms and terms used in
probability
ISO 3696, Water for analytical laboratory use — Specification and test methods
ISO 10132, Textiles — Textured filament yarn — Definitions
3  Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 10132 and the following 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/ ui
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
crimp modulus
ratio of difference between the straightened length (L ) and the length (L ) of the yarn under a low tension,
g f
to the straightened length (L ), as to characterize the elongation behaviour of a textured yarn in the range of
g
crimp elasticity
Note 1 to entry: It is expressed as a percentage.
4  Principle
Textured filament yarns have a certain crimp trend. By certain methods, the crimp is gradually revealed.
The variations in lengths, measured in crimped state and in straightened state, are used to calculate crimp
contraction and other parameters, as to characterise crimp properties of textured filament yarns. The test
specimen is in the form of a skein or a simple loop.

5  Reagents
5.1  Aqueous solution
If crimp development Method B (see 10.1.2) is selected, distilled water or grade 3 water in accordance with
ISO 3696 shall be used, to which a non-ionic surfactant to a concentration of 0,1 g/l has been added. Different
concentrations of non-ionic surfactant may be allowed on agreement between the interested parties.
6  Apparatus
6.1  Skein winding reel
a) Reel, with a circumference of (1 000 ± 2,5) mm, driven either automatically or manually;
b) Traversing mechanism to avert overlapping while a number of skeins being wound at the same time;
c) Tensioning device, maintaining the specified tension to an accuracy of ±10 %;
d) Device to count the turns of the reel, preferably warning or stopping winding automatically, just prior to
the specified number of reel revolutions;
e) Suitable mechanism to reduce the reel circumference for easy removal of the skein.
6.2  Test specimen holder
a) Frame, with a row of hooks separately on the upper and lower ends, for hanging test specimens
vertically (see Figure 1). In order to prevent slipping inside the knotted ends, especially for coarse yarn
test specimens, the upper hooks possibly to be replaced by a clamping mechanism, while every test
specimen consisting of a simple loop in "U" shape, as to eliminate the need for knot;
b) Upper hooks or clamps fixed on the frame;
c) Lower hooks subjected to applied tension, moving without friction along the wires on both sides to
avoid test specimens twisting;
d) Over 600 mm in height, with test specimens adequately spaced apart so as not to touch each other.

Key
1 upper hook or clamp
2 lower hook
3 test specimen
4 wire
5 tension load
Figure 1 — Schematic diagram of test specimen holder
6.3  Device for length measurement
a) Device to measure the lengths of test specimens in vertical position;
b) Allowing to apply different tensions, either manually or automatically;
c) Equipped with a suitable length measuring system, to an accuracy of ±0,1 mm.
6.4  Ventilated oven
a) Equipped with adequate ventilation to reach the specified temperature within the range from 30 °C
to 130 °C and to maintain a temperature variation within ±2 °C in the immediate vicinity of the test
specimens;
b) Interior with a height of at least 600 mm to accommodate the test specimen holder (6.2, Figure 1) in an
upright position, and with sufficient volume in which the test specimen holder (6.2, Figure 1) does not
occupy more than 80 % of the volume;
c) Capable to hold test specimens including tension loads at lower ends in vertical position, without
contacting the interior sides of the oven.
6.5  Hot water container
a) Device equipped with a heater and temperature controller, capable to be set at 100 °C and to maintain
the temperature variation within ±3 °C in the immediate vicinity of the test specimens;
b) Interior with a height of at least 600 mm high to accommodate the test specimen holder (6.2, Figure 1)
in an upright position and assure the test specimen holder (6.2, Figure 1) completely immersed by hot
water;
c) If necessary, the container may be equipped with a mechanism to fix the test specimen holder.

6.6  Device for tension application
a) Device with loading mechanism, to apply different tensions at the bottoms of test specimens, either
manually or automatically;
b) During application, avoiding the tension overshooting the target value more than 10 %.
7  Sampling
Sampling shall be performed as follows:
a) bulk laboratory sample shall be taken on request;
b) the number of lot sample and laboratory sample are listed in Table 1.
Packages that have been
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