CEN/TS 17158:2018

Composites made from cellulose based materials and thermoplastics (usually called wood polymer composites (WPC) or natural fibre composites (NFC)) - Determination of particle size of lignocellosic material

This document specifies mechanical and optical test methods for the determination of particle size of lignocellulosic material for use in wood plastic composites (WPC) and natural fibre composites (NFC).

Verbundwerkstoffe aus cellulosehaltigen Materialien und Thermoplasten (üblicherweise Holz-Polymer-Werkstoffe (WPC) oder Naturfaserverbundwerkstoffe (NFC) genannt) - Bestimmung der Partikelgröße von lignocellulosehaltigem Material

Dieses Dokument legt mechanische und optische Prüfverfahren zur Bestimmung der Partikelgröße von lignocellulosehaltigem Material zur Verwendung in Holz-Polymer-Werkstoffen (WPC) und Naturfaserverbundwerkstoffen (NFC) fest.

Composites à base de matières cellulosiques et de thermoplastiques (communément appelés composites bois-polymères (WPC) ou composites fibres d'origine naturelle (NFC)) - Détermination des dimensions de particles de matières ligocellulosiques

Kompoziti iz materialov na osnovi celuloze in termoplastov (običajno se imenujejo lesni polimerni kompoziti (WPC) ali kompoziti iz naravnih vlaken (NFC)) - Ugotavljanje velikosti delcev lignoceluloznega materiala

Te tehnične specifikacije določajo mehanske in optične preskusne metode za ugotavljanje velikosti delcev lignocelulozega materiala za uporabo v lesnih polimernih kompozitih (WPC) ali kompozitih iz naravnih vlaken (NFC).

General Information

• Status: Published
• Publication Date: 24-Apr-2018
• ICS: 79.080 - Semi-manufactures of timber
• ICS: 83.080.01 - Plastics in general
• ICS: 83.140.99 - Other rubber and plastics products
• Technical Committee: CEN/TC 249 - Plastics
• Drafting Committee: CEN/TC 249/WG 13 - Wood Plastics Composites (WPC)
• Current Stage: 6060 - Definitive text made available (DAV) - Publishing
• Start Date: 25-Apr-2018
• Due Date: 30-Nov-2018
• Completion Date: 25-Apr-2018
• Ref Project: SIST-TS CEN/TS 17158:2018 - Composites made from cellulose based materials and thermoplastics (usually called wood polymer composites (WPC) or natural fibre composites (NFC)) - Determination of particle size of lignocellosic material

Overview

CEN/TS 17158:2018 is a CEN Technical Specification that defines accepted mechanical and optical methods to determine particle size of lignocellulosic materials used in wood polymer composites (WPC) and natural fibre composites (NFC). Approved for provisional application in December 2017, the document provides method choices, apparatus guidance and calibration notes to support manufacturers, compounders and quality laboratories.

Key objectives:

• Provide reproducible procedures for particle size measurement
• Enable comparison of raw and processed lignocellulosic fillers
• Support formulation development and quality assurance for WPC/NFC

Key Topics

• Measurement principles: The specification covers three principal approaches:

  • Mechanical sieve analysis (vibrating sieve and air-jet sieve)
  • Optical image analysis (static image analysis using flat-bed scanners)
  • Dynamic image analysis (automatic dispersion with jet air and CMOS cameras)

• Apparatus guidance:

  • Vibrating sieve analysis is recommended for non-agglomerating material and an expected size range up to the millimetre scale.
  • Air-jet sieve analysis (EN ISO 4610 referenced) is suitable for finer ranges and materials that may tend to agglomerate.
  • Static image analysis uses manual dispersion on transparent foil and scanning; dynamic systems use automatic dry dispersion with image acquisition.

• Calibration and verification:

  • Optical scanner systems are calibrated using reference spheres (example: 600 µm spheres) and verified with synthetic fibres.
  • Dynamic systems require calibration and frequent verification of thresholds and sensors.
  • Where manufacturer recommendations apply (sieve equipment, air-jet), no additional calibration is required beyond correct operation.

• Interpretation:

  • Sieve analysis yields diameter-based size distributions (mass-based, no shape info).
  • Optical methods provide length, width and shape parameters (length/width ratio) but cannot be directly equated to sieve results without considering weighting and resolution differences.

Applications

• Product development: Tune filler particle size to influence mechanical strength, water uptake and swelling in WPC/NFC formulations.
• Quality assurance: Verify consistency of incoming lignocellulosic raw materials and detect degradation after compounding or extrusion.
• Material comparison: Compare wood flour with alternative lignocellulosic fillers using standardised measurement methods.

Related Standards

• EN ISO 4610 (air-jet sieve analysis)
• ISO 9276-6 and ISO 13322-2 (particle size / image analysis guidance)
• DIN 66165 parts 1 and 2 (sieving fundamentals and procedures)
• Reference to EN 15534-1 / prEN 15534-2 for WPC compound testing

This specification is practical for laboratories and manufacturers seeking harmonised, repeatable particle size data to inform formulation, processing and quality control of wood-based and natural-fibre composites.

Standards Content (Sample)

SLOVENSKI STANDARD
01-julij-2018
.RPSR]LWLL]PDWHULDORYQDRVQRYLFHOXOR]HLQWHUPRSODVWRYRELþDMQRVHLPHQXMHMR
OHVQLSROLPHUQLNRPSR]LWL:3&DOLNRPSR]LWLL]QDUDYQLKYODNHQ1)&
8JRWDYOMDQMHYHOLNRVWLGHOFHYOLJQRFHOXOR]QHJDPDWHULDOD
Composites made from cellulose based materials and thermoplastics (usually called
wood polymer composites (WPC) or natural fibre composites (NFC)) - Determination of
particle size of lignocellosic material
Verbundwerkstoffe aus cellulosehaltigen Materialien und Thermoplasten (üblicherweise
Holz-Polymer-Werkstoffe (WPC) oder Naturfaserverbundwerkstoffe (NFC) genannt) -
Bestimmung der Partikelgröße von lignocellulosehaltigem Material
Composites à base de matières cellulosiques et de thermoplastiques (communément
appelés composites bois-polymères (WPC) ou composites fibres d'origine naturelle
(NFC)) - Détermination des dimensions de particles de matières ligocellulosiques
Ta slovenski standard je istoveten z: CEN/TS 17158:2018
ICS:
79.080 Polizdelki iz lesa Semi-manufactures of timber
83.080.01 Polimerni materiali na Plastics in general
splošno
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

CEN/TS 17158
TECHNICAL SPECIFICATION
SPÉCIFICATION TECHNIQUE
April 2018
TECHNISCHE SPEZIFIKATION
ICS 79.080; 83.080.01; 83.140.99
English Version
Composites made from cellulose based materials and
thermoplastics (usually called wood polymer composites
(WPC) or natural fibre composites (NFC)) - Determination
of particle size of lignocellosic material
Composites à base de matières cellulosiques et de Verbundwerkstoffe aus cellulosehaltigen Materialien
thermoplastiques (communément appelés composites und Thermoplasten (üblicherweise Holz-Polymer-
bois-polymères (WPC) ou composites fibres d'origine Werkstoffe (WPC) oder Naturfaserverbundwerkstoffe
naturelle (NFC)) - Détermination des dimensions de (NFC) genannt) - Bestimmung der Partikelgröße von
particles de matières ligocellulosiques lignocellulosehaltigem Material
This Technical Specification (CEN/TS) was approved by CEN on 10 December 2017 for provisional application.

The period of validity of this CEN/TS is limited initially to three years. After two years the members of CEN will be requested to
submit their comments, particularly on the question whether the CEN/TS can be converted into a European Standard.

CEN members are required to announce the existence of this CEN/TS in the same way as for an EN and to make the CEN/TS
available promptly at national level in an appropriate form. It is permissible to keep conflicting national standards in force (in
parallel to the CEN/TS) until the final decision about the possible conversion of the CEN/TS into an EN is reached.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, 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
© 2018 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN/TS 17158:2018 E
worldwide for CEN national Members.

Contents Page
European foreword . 3
Introduction . 4
1 Scope . 5
2 Normative references . 5
3 Principle . 5
4 Apparatus . 5
4.1 Vibrating sieve analysis . 5
4.2 Air jet sieve analysis . 5
4.3 Static image analysis systems . 6
4.4 Dynamic image analysis systems using automatic dispersion by jet air and image
acquisition with a CMOS-camera . 6
5 Calibration . 6
5.1 Vibrating sieve analysis . 6
5.2 Air jet sieve analysis . 6
5.3 Static image analysis systems . 6
5.4 Dynamic image analysis systems . 6
6 Procedure. 7
6.1 Sampling and preparation of test specimens . 7
6.1.1 General . 7
6.1.2 Vibrating sieve analysis . 7
6.1.3 Air jet sieve analysis . 7
6.1.4 Static image analysis systems . 7
6.1.5 Dynamic image analysis systems . 7
6.2 Observation and measurement. 7
6.2.1 Vibrating sieve analysis . 7
6.2.2 Air jet sieve analysis . 7
6.2.3 Static image analysis systems . 7
6.2.4 Dynamic image analysis systems . 8
6.3 Expression of results . 8
6.3.1 Vibrating sieve analysis . 8
6.3.2 Air jet sieve analysis . 8
6.3.3 Static image analysis systems . 8
6.3.4 Dynamic image analysis systems . 8
6.4 Test report . 8
6.4.1 Vibrating sieve analysis . 8
6.4.2 Air jet sieve analysis . 9
6.4.3 Static image analysis systems . 9
6.4.4 Dynamic image analysis systems . 9
Bibliography . 10

European foreword
This document (CEN/TS 17158:2018) has been prepared by Technical Committee CEN/TC 249
“Plastics”, the secretariat of which is held by NBN.
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.
According to the CEN/CENELEC Internal Regulations, the national standards organisations of the
following countries are bound to announce this Technical Specification: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta,
Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.
Introduction
Either optical systems or sieve analysis can be used for the determination of particle size of wood flour
or flour based on alternative lignocellulosic materials for use in wood plastic composites. Microscopic
analysis is also possible but requires a significant amount of time and effort to generate statistically
viable results, hence, it is not suggested for this task. Particle size determination can be performed using
raw material as well as processed and extracted material to observe the effects of processing on particle
size. Optical systems and in addition, sieve analysis can be performed using a vibrating sieve or an air-
jet sieve in order to match results from optical measurements with those from mechanical
measurements and which are suitable to determine the mass of particles which are too fine or too
coarse. Sieve analysis does not generate any information regarding the shape of the particles and leads
only to a diameter-based, coarse size distribution. Therefore, size parameters supplied by optical
measurements cannot directly be compared with those from sieve analysis. Methods using active air-jet
dispersion are particularly suitable for material containing long natural fibres which tend to
agglomerate. Optical methods derive very similar results regarding the type of distribution and its
characteristic percentiles for the particle length and a shape factor (length/width ratio) if optical
resolution and weighting method are comparable. For a comparison between these measurement
principles see (Plinke et. al 2016 [2]).
This document is related to the determination of particle size of the lignocellulosic material used in the
preparation of wood-polymer composites according to EN 15534-1 and prEN 15534-2 for compounds.
Furthermore, the methods mentioned in this document can be used to determine the extent of particle
degradation after processing, i.e. after compounding and/or extrusion and injection-moulding.
Manufacturers of wood and other natural fibre producers and users of wood and natural fibres can use
the methods described in this document to determine particle size of their lignocellulosic raw materials
and to compare the particle size of their raw materials to alternative lignocellulosics. There are no
requirements for particle size of the lignocellulosic fillers used in WPC, however, it is useful to know
particle size for formulation development and to understand the relationship between particle size and
WPC properties such as strength, water uptake and swelling.
1 Scope
This document specifies mechanical and optical test methods for the determination of particle size of
lignocellulosic material for use in wood plastic composites (WPC) and natural fibre composites (NFC).
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
...