ISO 15360-3:2024

International
Standard
ISO 15360-3
First edition
Recycled pulps — Estimation of
2024-05
stickies and plastics —
Part 3:
Determination and identification
by applying near-infrared
measurement
Reference number
© ISO 2024
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ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 2
5 Apparatus (near-infrared analysis system) . 2
5.1 Hardware (measuring device) .2
5.2 Software .2
5.3 Penetration test reference piece .2
5.4 Calibration of the NIR sensor .2
6 Preparation of specimen . 3
6.1 General .3
6.2 Pulp samples .3
6.2.1 Measurement of stickies and non-tacky contaminants deposited on filter .3
6.2.2 Measurement of stickies and non-tacky contaminants directly on paper or
handsheets .3
6.3 Paper samples.3
7 Procedure . 4
7.1 Parameters for the analysis .4
7.2 Placement of specimen .4
7.3 Measurement .4
7.4 Penetration test .5
8 Analysis . . 5
8.1 Determination of stickies and non-tacky polymeric contaminants .5
8.2 Calculation .6
8.2.1 Pulp samples .6
8.2.2 Paper samples .7
9 Precision . 9
10 Test report . 9
Annex A (normative) Calibration check .10
Annex B (informative) Example for measuring devices .11
Bibliography .12

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 through
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The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types
of ISO document 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).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
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This document was prepared by Technical Committee ISO/TC 6, Paper, board and pulps.
A list of all parts in the ISO 15360 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
Tacky particles, commonly named stickies, are a major issue in paper recycling since they can affect the
processes as well as the quality of the recycled products. Therefore, a variety of test methods have been
developed over decades. Existing laboratory test procedures for sticky contaminants in pulps made
from paper for recycling or in recycled papers require an elaborate sample preparation to increase the
concentration of these sticky contaminants by screening the pulp through a slotted plate and analysing the
rejects. With the test procedure and equipment based on this document, the content of sticky contaminants
can be determined at a laboratory handsheet or at the paper by means of near-infrared (NIR) measurement
but also on filter paper where stickies have been concentrated and deposited with existing test procedures.
The approach to the measurements specified in this document is different from established test methods
because the amount and chemical composition of polymeric substances are determined by applying NIR
measurements. The content of these substances, which are typical constituents of adhesives are assigned
as stickies. This is a further major difference from existing methods, which typically analyse the sticky
behaviour, but not the chemical composition. The results determined by applying the method specified in
this document correlate very well with established sticky measurement techniques, e.g. ISO 15360-2 or
[1]
INGEDE Method 4. The measurement procedure in this document also enables to simultaneously analyse
polymeric substances without tacky behaviour, typically called “plastics” in other methods.
The method described here can be implemented by any system that combines particle size measurement
[2,3]
and NIR analysis. For example, “3DStick” involves laser triangulation to determine size and location of
particles and subsequent NIR to determine chemical composition. Alternatively, direct camera imaging in
[4]
the NIR spectrum has been used to both locate and identify the chemical composition of particles. This
[5]
method can prove valuable for online measurement in systems that generate dry sheet samples .

v
International Standard ISO 15360-3:2024(en)
Recycled pulps — Estimation of stickies and plastics —
Part 3:
Determination and identification by applying near-infrared
measurement
1 Scope
This document specifies a method for the determination of stickies and non-tacky polymeric contaminants
present in pulp or paper sheets near-infrared measurement. This document is applicable to recycled pulps
and papers.
Sampling of pulp and paper as well as the preparation of handsheets are outside the scope of this document.
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 216, Writing paper and certain classes of printed matter — Trimmed sizes — A and B series, and indication
of machine direction
ISO 534, Paper and board — Determination of thickness, density and specific volume
ISO 536, Paper and board — Determination of grammage
ISO 4119, Pulps — Determination of stock concentration
ISO 5263-2, Pulps — Laboratory wet disintegration — Part 2: Disintegration of mechanical pulps at 20 degrees C
ISO 5269-1, Pulps — Preparation of laboratory sheets for physical testing — Part 1: Conventional sheet-
former method
ISO 5269-2, Pulps — Preparation of laboratory sheets for physical testing — Part 2: Rapid-Köthen method
ISO 5270, Pulps — Laboratory sheets — Determination of physical properties
ISO 15360-1, Recycled pulps — Estimation of Stickies and Plastics — Part 1: Visual method
ISO 15360-2, Recycled pulps — Estimation of Stickies and Plastics — Part 2: Image analysis method
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
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/

3.1
stickies
diverse group of materials in disintegrated pulp that can adhere to objects at ambient temperature or can
adopt adhesive characteristics when subjected to elevated temperature, elevated pressure or change of pH
[SOURCE: ISO 4046-2:2016, 2.61, modified — two instances of the word "may" replaced with "can".]
3.2
non-tacky polymeric contaminant
polymeric substance that is usually not found in adhesives, excluding cellulosic materials and inorganic
substances
Note 1 to entry: ISO 15360-2 defines these substances as “plastics”.
4 Principle
This document specifies the determination of the chemical composition of an air dry paper sample applying
a near-infrared (NIR) analysis system. The sample to be analysed can have various origins – pulp, paper
machine, pilot plant, laboratory etc. – but shall be made using recycled fibres. The surface areas of particles,
which are neither natural fibres nor inorganic substances are determined. The measurement differentiates
between stickies or non-tacky polymeric contaminants according to their chemical nature.
5 Apparatus (near-infrared analysis system)
5.1 Hardware (measuring device)
The measuring device is a hyperspectral NIR imaging system. The illumination device, optics and sensor
shall cover at least the spectral range from 1 400 nm to 1 800 nm. The optical system has a lateral resolution
of at least 127 DPI (i. e. object pixel size ≤200 µm). The optical system may be of the wide-field type, or of the
point-, line- or wavelength-scanning type.
Annex A details the characteristics of such compatible hyperspectral NIR systems.
It is recommended that the system allows analysing paper sheets of ISO A4 according to ISO 216 format or larger.
5.2 Software
The required software is a NIR evaluation system for qualitative and quantitative assessment of polymeric
substances by size and number. The software shall consist of an NIR imaging algorithm, including
chemometrics and classification.
For examples, see Annex B.
5.3 Penetration test reference piece
A film or plate with an approximate size of ISO A4 in accordance with ISO 216 and a maximum thickness of
300 µm consisting of at least one polymeric substance, which is assigned to the sticky or non-tacky polymeric
contaminants group (see 8.1).
5.4 Calibration of the NIR sensor
Calibration shall be done according to the manual of the respective device. The calibration shall be checked
in accordance with Annex A.
6 Preparation of specimen
6.1 General
In the case of determination of plastics and stickies deposited on filter paper, the measurement can be
performed directly, without the need of the penetration test defined in 7.4.
In the case of determination on paper sample, the NIR signal can be submitted through a limited specimen
thickness only. For pulp or paper sheets, this specimen thickness is depending on the fibre type, the degree
of densification, the filler content and the like. Therefore, a penetration test shall be performed to determine
whether the thickness of the specimen is below the maximum allowable specimen thickness δ (see 7.4).
max
6.2 Pulp samples
6.2.1 Measurement of stickies and non-tacky contaminants deposited on filter
The contaminants shall be isolated in accordance to ISO 15360-1 or ISO 15360-2 and deposited on filter paper
before air drying. The oven dry mass of pulp used to concentrate the contaminants shall be determined.
6.2.2 Measurement of stickies and non-tacky contaminants directly on paper or handsheets
Determine the oven-dry mass of the stock used for preparing the handsheets in accordance with ISO 4119.
Prepare handsheets having
...