1、BRITISH STANDARDBS ISO 17751:2007Textiles Quantitative analysis of animal fibres by microscopy Cashmere, wool, speciality fibres and their blends ICS 59.060.10g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g
2、55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58BS ISO 17751:2007This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 December 2007 BSI 2007ISBN 978 0 580 53891 9National forewordThis British Standard is the UK implementation of ISO
3、17751:2007.The UK participation in its preparation was entrusted to Technical Committee TCI/80, Chemical testing of textiles.A list of organizations represented on this committee can be obtained on request to its secretary.This publication does not purport to include all the necessary provisions of
4、a contract. Users are responsible for its correct application.Compliance with a British Standard cannot confer immunity from legal obligations.Amendments issued since publicationAmd. No. Date CommentsReference numberISO 17751:2007(E)INTERNATIONAL STANDARD ISO17751First edition2007-12-01Textiles Quan
5、titative analysis of animal fibres by microscopy Cashmere, wool, speciality fibres and their blends Textiles Analyse quantitative des fibres animales par microscopie Cachemire, laine, fibres spciales et leurs mlanges BS ISO 17751:2007ii iiiContents Page Foreword iv Introduction v 1 Scope . 1 2 Cauti
6、on. 1 3 Normative references . 1 4 Terms and definitions. 1 5 Principle. 3 6 Apparatus and reagents. 3 7 Preparation of the test specimens 5 8 Procedure 6 9 Test report . 11 Annex A (informative) Scale structures of cashmere and wool fibres . 12 Annex B (informative) Sampling and preparation procedu
7、res 16 Annex C (informative) Precision and accuracy. 18 Bibliography . 20 BS ISO 17751:2007iv 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 carrie
8、d out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. IS
9、O collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare Internatio
10、nal Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the ele
11、ments of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 17751 was prepared by Technical Committee ISO/TC 38, Textiles, Subcommittee SC 23, Fibres and yarns. This International Standard is based on IWTO-58-00, Sc
12、anning Electron Microscopic Analysis of Speciality Fibres and Sheeps Wool and their Blends, copyright the International Wool Textile Organisation (IWTO), used with permission of IWTO. BS ISO 17751:2007vIntroduction Labelling textiles to indicate their composition is necessary according to relevant l
13、aws and regulations, not only for the final products but also for the raw materials at different stages of processing. Stringent labelling regulations for textile products at all stages of processing have compelled the manufacturers to state not only the types of fibre but also the mass percentages
14、of the fibres contained in their goods. Wool and speciality fibres (cashmere, mohair, llama/alpaca, camel hair, angora rabbit hair, etc.) exhibit great similarities in their physical and chemical properties, so that their blends cannot be separated mechanically or chemically. Light microscopy (LM) h
15、as traditionally been applied for fibre identification and blend analysis. Wool has a long tradition as the main substitute in mislabelling when it is blended with animal fibres such as mohair and cashmere. A reliable method, complementing the current and widely used standards based on light microsc
16、opy, for distinguishing wool from all other speciality fibres is therefore of major technical and commercial importance. A technique using scanning electron microscopy (SEM) for the discrimination of wool and speciality animal fibres, based on the assessment of cuticle scale edge heights, was introd
17、uced and developed during the 1980s and early 1990s. Although SEM illustrates topographical features extremely well, it is incapable of describing internal fibre structures. Fortunately, this deficiency can be complemented by LM which is capable of illustrating internal features. For all these reaso
18、ns, it is insufficient to depend on only one form of microscopy and it is advantageous to utilize both LM and SEM techniques. The identification of animal fibres is so complex that it is often necessary to consider subtle characteristics that require a multidisciplinary microscopic approach. BS ISO
19、17751:2007blank1Textiles Quantitative analysis of animal fibres by microscopy Cashmere, wool, speciality fibres and their blends 1 Scope This International Standard specifies a method for the identification and quantitative analysis of wool and speciality animal fibres using both light microscopy (L
20、M) and scanning electron microscopy (SEM). This standard is also applicable to blends of animal fibres and products made from them. NOTE 1 Difficulty may be encountered when attempting the analysis of deeply dyed or heavily pigmented fibres by LM. In such cases, mild dye-stripping or pigment-bleachi
21、ng procedures may be applied prior to analysis. NOTE 2 SEM is not an appropriate technique for the analysis of blends containing medullated fibres since the medullae will not be visible. 2 Caution The microscopic analysis of blends of animal fibres requires a high degree of operator skill and experi
22、ence. Only when authentic reference samples have been successfully identified by multiple replications over a prolonged period, and trial blends of known composition have been tested with acceptable results, should official analysis be performed by an operator. 3 Normative references The following r
23、eferenced documents are indispensable for the application 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 6938, Textiles Natural fibres Generic names and definitions
24、4 Terms and definitions For the purposes of this document, the following terms and definitions apply. 4.1 CRT cathode ray tube or display screen 4.2 false scale edge shoulder step-like structure on the surface of a cuticle cell, which may be mistaken for the scale edge 4.3 light microscope optical i
25、nstrument used to produce magnified images NOTE Light microscopes may be of the reflected-light, transmitted-light or light-projection type. Either a transmitted-light type or a light-projection type is preferred for this type of analysis. BS ISO 17751:20072 4.4 medulla series of cavities formed in
26、the central portion of some animal fibres when cells collapse during growth 4.5 sample portion representative of the batch of material from which it is taken 4.6 scale cuticle covering the surface of animal fibres 4.7 scale density number of scales per millimetre of fibre 4.8 scale edge thick, dista
27、l end of the cuticle cell exposed towards the tip of the fibre 4.9 scale thickness height of the cuticle at the scales edge 4.10 scanning electron microscope electron-optical instrument that examines and analyses the physical information (such as secondary electron, backscattered electron, absorbed
28、electron and X-ray radiation) obtained by generating electron beams and scanning the surface of the sample in order to determine the structure composition and topography of the sample 4.11 secondary electron image SEI scanning image which is obtained by modulating the brightness of a cathode ray tub
29、e (CRT) with the detected secondary electron signal 4.12 snippet small sections of fibre cut from a sample 4.13 speciality fibre any animal source (type) of keratin fibre other than wool: i.e. cashmere goat, angora goat (mohair), angora rabbit hair, camel hair, cashgora goat, llama/alpaca hair, shah
30、toosh hair, vicuna hair, yak hair, horse hair NOTE 1 Photographs of the animal fibres listed may be found in AATCC Test Method 20 and IWTO 58-00 (see Bibliography). NOTE 2 Trade in some animal fibres (e.g. shahtoosh, vicuna, yak) is not always allowed because the animals are protected. Animals under
31、 protection are listed in the Washington Convention. 4.14 test specimen portion taken from randomized snippets for measurement purposes BS ISO 17751:200735 Principle Following sampling, short fibre snippets are obtained from the material to be tested. The snippets comprising a test specimen are dist
32、ributed uniformly on suitable sample holders. For light microscopy (LM), test specimens are analysed optically and measured using a graduated scale. For scanning electron microscopy (SEM), test specimens can be coated with a layer of gold before they are transferred into the microscope. At a magnifi
33、cation of 1 000, or another suitable magnification, the number of fibres from each animal source is determined by observing and identifying them under the microscope. With SEM, wool fibres can be differentiated from speciality fibres from all other sources on the basis of the height of their surface
34、 scales. The height at the true distal edge of wool cuticle cells (not at “false scale edges” or “shoulders”) reaches a value of 0,6 m or more, whereas the distal height of speciality fibres is 0,4 m or less. Edge height is generally a selective indicator for the fibre type. Other characteristics su
35、ch as scale pattern, scale frequency and diameter are also useful for unequivocal fibre identification. For a quantitative analysis of a binary blend, the mean diameters, and the related standard deviations, of the fibre components are determined together with the number of fibres of a given type, i
36、n order to calculate the percentage fibre content by number of fibres or by mass for each source of fibre. For angora rabbit hair, the reduced mean fibre density, due to consistent medullation, is taken into account. Practice shows that the experience of the operator with animal fibre identification
37、 is an important requirement for conducting reliable fibre analyses. 6 Apparatus and reagents 6.1 Light microscope 6.1.1 Type of microscope 6.1.1.1 Projection type The microscope proper shall comprise a light source, a light condenser, a stage which supports the mounted specimen of fibres, an object
38、ive, an ocular and a circular viewing screen. The stage shall be movable in two directions at right angles by means of sliding mechanisms capable of successive displacements in 0,5 mm steps. The objective and ocular shall be capable of providing a magnification of 500 at the screen. The circular scr
39、een shall have an associated measurement scale capable of rotation in the plane of the screen and about its centre. If this screen is not transparent, it shall have a movable scale 5 cm long, graduated on its underside in millimetres. The scale shall be capable of movement diametrically across the s
40、creen between guides. Transparent screens may incorporate a scale graduated in millimetres along a diameter. A movable scale is generally preferred. The circular screen shall contain a marked central circle whose diameter is equal to one-quarter of the optical distance between the ocular and the cen
41、tre of the screen. To ensure that any lens aberrations at the objective perimeter are avoided, all measurements shall be made within this circle. However, some modern instruments contain improved optics that ensure uniformity of the observation area, and no marked circle is required. In such cases,
42、the magnification should be checked over the whole projected image by using a certified micrometer scale. 6.1.1.2 Transmitted-light type The microscope proper shall comprise a light source, a light condenser, a stage, an objective and an ocular. The ocular shall be fitted with a calibrated graticule
43、 to permit measurement of the fibre diameter. The stage shall be movable in two directions at right angles by means of sliding mechanisms capable of successive displacements. The objective and ocular shall be capable of providing a magnification of 150 to 500. BS ISO 17751:20074 6.1.2 Slides and cov
44、er glasses Use glass microscope slides measuring 75 mm 40 mm. Square or rectangular cover glasses with a thickness of 0,13 mm to 0,17 mm can be used. 6.1.3 Mounting medium Use a mounting medium with the following properties: refractive index between 1,43 and 1,53; suitable viscosity; does not absorb
45、 water. NOTE Cedar wood oil and liquid paraffin are examples of suitable media. 6.1.4 Fibre-cutting devices 6.1.4.1 General For cutting the fibres to a predetermined length, the fibre holder and pushers described below may be used. Alternatively, a conventional microtome may be used if it is capable
46、 of fulfilling the requirements of 7.2 regarding the cutting of pieces of fibre. 6.1.4.2 Fibre holder and pushers The holder is a short piece of smooth steel about 3 mm thick with a 1,5 mm slot into which slides a tongue. The tongue is fixed by a screw and may thus be adjusted to project different d
47、istances into the slot. The pushers consist of three steel stems with shortstop plates near their ends; all the stems have the same width as the slot, namely 1,5 mm. The stem of one pusher extends 0,8 mm beyond the stop plate, that of the second 0,6 mm and that of the third 0,4 mm. 6.2 Scanning elec
48、tron microscope 6.2.1 Operating conditions Accelerating voltage: 15 kV to 20 kV. Beam current: 300 pA to 500 pA. Pressure in the sample chamber: 1,2 mm) and reverse the direction of scanning of the mounting stub. 8.2.2 Fibre identification The height of the distal edge of the cuticle scale, a crucia
49、l characteristic of fibre type, is determined on the fibre surface at a magnification that makes it possible to decide whether the scale edges are “high” (0,55 m for wool) or “low” ( 0,55 m for speciality fibres). For fibres where the distinction is not obvious, examine several cuticle scale edges at high magnification settings, such as 3 000 to 10 000, until confident of the identification. Observations of further fibre surface characteristics, such as scale frequency and scale patterns, may be necessary to assist the operator with some fibre i
