ISO/TS 21256-4:2023

Fine bubble technology - Cleaning applications - Part 4: Test method for oil removal from polyester-based textile

This document specifies a test method to evaluate the oil removal performance from polyester-based textile with fine bubbles.

Technologie des fines bulles — Applications de nettoyage — Partie 4: Méthode d'essai pour l'élimination de l'huile sur un tissu en polyester

General Information

• Status: Published
• Publication Date: 29-May-2023
• ICS: 07.030 - Physics. Chemistry
• Technical Committee: ISO/TC 281 - Fine bubble technology
• Drafting Committee: ISO/TC 281/WG 3 - Applications of fine bubble technology
• Current Stage: 6060 - International Standard published
• Start Date: 30-May-2023
• Due Date: 26-Aug-2024
• Completion Date: 30-May-2023

Overview

ISO/TS 21256-4:2023 - "Fine bubble technology - Cleaning applications - Part 4: Test method for oil removal from polyester-based textile" specifies a reproducible laboratory procedure to evaluate oil removal performance from polyester-based textiles using fine-bubble water. The technique quantifies oil removal by measuring textile mass and brightness before and after exposure to circulating fine-bubble water, enabling objective comparison of cleaning effectiveness across bubble sizes, concentrations and process parameters.

Key topics and technical requirements

• Scope: Test method focused on polyester-based textiles (e.g., PET, PBT, PTT) to assess oil removal performance using fine bubbles.
• Measurement principle: Determine oil removal by mass difference of the textile sample before soiling, after controlled soiling, and after washing/drying; complement with ISO brightness (R457) to express cleanliness visually.
• Controlled contamination: Use coloured oils (e.g., lubricants and edible oil) dyed with Sudan Red III to standardize soiling and improve measurement repeatability.
• Equipment examples: Drying oven, precision electronic balance (high resolution), micropipette, beakers (250 ml and 2 000 ml), water diffuser/tripod, portable brightness meter and suspended stirring bar. Specific equipment performance (e.g., scale resolution, oven temperature control) is recommended to ensure reproducibility.
• Typical test parameters (from document): preset water flow 2 L/min, soaking duration 5 minutes, drying at 60 °C for 20 minutes, and a standard soiling mass (example 0.15 g coloured oil) - these provide a baseline protocol for comparative testing.
• Result reporting: Report initial and final masses, oil mass added, oil stain removal rate, brightness values, fine-bubble properties and any deviations from the procedure.
• Performance metric: Oil removal rate expressed as the fraction (or percentage) of oil removed based on pre- and post-wash mass measurements.

Applications and users

• Textile manufacturers and finishing houses assessing the effectiveness of fine-bubble cleaning for polyester fabrics.
• R&D labs developing fine-bubble generators, water treatment systems and low-detergent textile washing processes.
• Sustainability and recycling operations evaluating mechanical/physical cleaning (reduced detergent) for fabric recycling or pre-treatment.
• Equipment vendors and certification bodies comparing fine-bubble systems by standardized oil-removal performance.

Practical benefits include objective benchmarking of fine-bubble water against tap water, optimization of process parameters (bubble size, concentration, flow rate) and support for environmentally friendlier cleaning that reduces detergent use.

Related standards

• ISO brightness reference: ISO R457 (used for brightness measurement in this test).
• Other parts of the ISO 21256 series on fine bubble technology (see ISO website for the full series).

Keywords: ISO/TS 21256-4:2023, fine bubble technology, oil removal, polyester-based textile, test method, textile cleaning, oil stain removal rate, fine-bubble water, ISO brightness.

Standards Content (Sample)

TECHNICAL ISO/TS
SPECIFICATION 21256-4
First edition
2023-05
Fine bubble technology — Cleaning
applications —
Part 4:
Test method for oil removal from
polyester-based textile
Technologie des fines bulles — Applications de nettoyage —
Partie 4: Méthode d'essai pour l'élimination de l'huile sur un tissu en
polyester
Reference number
© ISO 2023
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
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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
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 1
5 Test methods . 1
5.1 Equipment and material. 1
5.1.1 Drying Oven . 1
5.1.2 Digital electronic scale . 2
5.1.3 Dye . 2
5.1.4 Oil . 2
5.1.5 Substrate . 2
5.1.6 Micropipette . 3
5.1.7 Beaker . 3
5.1.8 Tripod stand . 3
5.1.9 Portable brightness meter . 3
5.1.10 Suspended stirring bar . 4
5.2 Procedure . 4
5.3 Oil removal determination . 5
6 Test report . 5
Annex A (informative) Oil removal performance comparison between tap water and fine
bubble water . 6
Bibliography .17
iii
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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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
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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 281, Fine bubble technology.
A list of all parts in the ISO 21256 series can be found on the ISO website.
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
Introduction
In recent years, the market has witnessed a proliferation of new products using fine bubble technology.
In the field of textile industry, the introduction of fine bubbles can bring many interesting effects. Using
fine bubbles can increase the cleaning efficiency by removal of the residual surface oil of textile in
large-scale manufacturing in order to improve the quality of dyeing and finishing process. Especially,
polyester-based textile takes very important role in the textile industry since its outstanding features.
In addition, fine bubble washing is a physical cleaning method which can reduce the pollution of
detergent to the water environment. So, it is needed to design a general test method, for textile
manufacturers and related researchers, to evaluate the cleaning efficiency by removal of fine bubble
water on polyester-based textile.
In order to adapt to complex usage scenarios in large-scale textile manufacturing, the proposed method
uses the mass fraction of oil on polyester-based textile after and before washing to characterize the
[1]
cleaning effect, and uses ISO brightness (R457) to assist in expressing the degree of cleanliness.
To demonstrate, a lubricant, whose main composition is high molecular hydrocarbon, is used as an
identical contaminant in production, and an edible oil, whose main composition is fatty acid, is used as
an identical contaminant in daily washing. The method is simple, reproducible and highly versatile.
With this method, the oil removal ability of fine bubble water with different bubble sizes and
concentrations can be compared. Furthermore, it will further promote the civil and industrial
application of oil removal from textile of fine bubbles, for example, washing during fabric recycling
process or cleaning with less detergent.
v
TECHNICAL SPECIFICATION ISO/TS 21256-4:2023(E)
Fine bubble technology — Cleaning applications —
Part 4:
Test method for oil removal from polyester-based textile
1 Scope
This document specifies a test method to evaluate the oil removal performance from polyester-based
textile with fine bubbles.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
4 Principle
In the textile industry, various types of manufacturing machines use different kinds of oils, surfactants
and detergents. During the production either the oils are coated over the whole surface of the strings
uniformly or the whole surface of the textile in different processes. To test the removal ability, identical
samples should be used, e.g. always to use polyester-based textile, for better comparative consistency
in the method.
The test method consists in determining the mass fraction of oil on a textile sample before and after
cleaning. A weighed polluted sample is soaked in the circulated bubble water. To evaluate the degree of
cleanliness, the mass fraction of residual oil on the sample is determined, and the brightness according
[1],[2]
to ISO is also evaluated.
5 Test methods
5.1 Equipment and material
5.1.1 Drying Oven
Figure 1 shows the drying oven’s appearance. The power is 4 kW, and the working temperature range is
approximately +10 °C to 250 °C with ±1 °C accuracy.
Figure 1 — Drying oven
5.1.2 Digital electronic scale
Figure 2 shows the digital electronic scale used in this test, whose maximum range is 220 g and
resolution is 0,001 g.
Figure 2 — Digital electronic scale
5.1.3 Dye
Sudan Red III (C H N O), AR.
22 16 4
5.1.4 Oil
Lubricant, whose main composition is high molecular hydrocarbon, and edible oil, whose main
composition is fatty acid. The two typical kinds of oils are described in Annex A.
5.1.5 Substrate
The polyester-based textiles, such as Polyethylene terephthalate (PET), Polybutylene terephthalate
(PBT) and Polytrimethylene terephthalate (PTT) are used as substrates. The ability of oil removing
depends on all of their characteristics, i.e. weaving types of manufacturing, the diameter of thread.
Therefore, the specification of the textile characteristics should be clarified in detail for cleaning
applications to obtain the repeatability of the experiments. Annex A describes an example of oil removal
performance comparison between tap water and fine bubble water, in which the substrate is clearly
described.
5.1.6 Micropipette
Figure 3 shows the micropipette used in this test, whose resolution is 0,01 ml.
Figure 3 — Micropipette
5.1.7 Beaker
250 ml and 2 000 ml.
5.1.8 Tripod stand
Load polyester-based textile pieces at the tripod stand presented in Figure 4.
Figure 4 — Tripod stand
5.1.9 Portable brightness meter
The portable brightness meter used in this test is shown in Figure 5, which resolution is 0,1 %.
Figure 5 — Portable brightness meter
5.1.10 Suspended stirring bar
The suspended stirring bar as shown in Figure 6 is used to reduce the influence of uneven flow on the
performance of oil removal.
Figure 6 — Suspended stirring bar
The test method allows to use other equipment or materials different from those specified in 5.1,
provided their technical characteristics are satisfying and not inferior to those described and specified
in 5.1.
5.2 Procedure
— Fully dry the sample to minimize the moisture content.
— Weigh the dried sample within 30 s to avoid the influence of environmental humidity as the initial
mass of textile.
— Dye the oil with Sudan Red III.
— Contaminate the sample with specific amount of coloured oil and weigh out the net weight of oil.
— Allow the coloured oil to spread for better stability.
[1]
— Test the ISO brightness (R457) as the initial brightness of textile.
— Preset a water flow rate to 2 l/min, allow the test water to overflow out o
...