Safeguards 09508 Quantitative Analysis of Animal Fibres.Pub
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SAFEGUARDS SGS CONSUMER TESTING SERVICES SOFTLINES NO. 095/08 NOVEMBER 2008 TESTING STANDARDS FOR QUANTITATIVE ANALYSIS OF ANIMAL FIBRES BY MICROSCOPY - CASHMERE, WOOL, SPECIALITY FIBRES AND THEIR BLENDS Natural fibres are used extensively in today’s textile market in the return fashion on demanding natural and comfort feelings and environmental awareness. Cashmere named as “soft gold” due to its softness and rarity. It was only available to imperial families in the past, although Cashmere has become more affordable nowadays. Substitution of Cashmere with wool or other animal fibres can lead to big rewards due to the huge price difference between fibres. However, mislabeling of textile products can cause huge loss with fine and product recall, or even worse, to lose the reputation in the market. In January 2007, a law has been made in United States with stricter measurement in Cashmere labeling to protect buyers and consumer’s benefit and it is becoming the trend of luxury fibre protection globally. The Cashmere and Camel Hair Manufacturers Institute (CCMI) has also their definition for Cashmere. Therefore, understanding the fibre identification and testing procedures and ensuring your products labelled correctly will help you prevent unnecessary loss. SOFTLINES NO. 095/08 NOVEMBER 2008 P.2 Currently, there are some testing methods to be used for quantitative analysis of animal fibres by microscopy - Cashmere, wool, specialty fibres and their blends. • AATCC 20A-- Fibre Analysis: Quantitative, section 14— microscopical analysis procedures, • ISO 17751 – Quantitative analysis of animal fibres by microscopy - Cashmere, wool, speciality fibres and their blends (including Light Microscope & Scanning Electron Microscope method), The Cashmere and Camel Hair Manufacturers Institute defines cashmere as: • IWTO-58 – Scanning Electron Microscopic analysis of • The fine (dehaired) undercoat fibers produced by a Cashmere goat (Capra hircus speciality fibres and sheep’s laniger). wool and their blends, • The fiber is generally non-medullated and has a mean maximum diameter of 19 • GB/T 16988 – Quantitative microns. The co-efficient of variation around the mean shall not exceed 24%. determination for mixtures of There can be no more than 3% (by weight) of cashmere fibers over 30 microns. special animal fibre and wool. (Reference IWTO Test Method 8-89). The U.S. Wool Products Labeling Act of 1939, as amended, (U.S.C. 15 Section 68b (a)(6)) defines cashmere as: (A) the fine (dehaired) undercoat fibers produced by a cashmere goat (capra hircus laniger); (B) the average diameter of the fiber of such wool product not exceeding 19 microns; and (C) containing not more than 3 percent (by weight) of cashmere fibers with average diameters that exceed 30 microns. The average fiber diameter may be subject to a coefficient of variation around the mean that shall not exceed 24 percent. The microscopic analysis of blends of animal fibres requires a high degree of operator skill and experience. Without extensive knowledge of fibre identification and testing experiences, it is very easy to misidentify fibres when most of the dispute caused. It may not be sufficient to depend on only one form of microscopy and it is advantageous to utilize both light or scanning electron microscopic techniques. The identification of animal fibres is so complex that it is often necessary to consider subtle characteristics that require a multidisciplinary microscopic approach. SOFTLINES NO. 095/08 NOVEMBER 2008 P.3 Comparison between Light Microscopy and Scanning Electron Microscopy Method Microscope LM –Light Microscopy SEM – Scanning Electron Microscopy Fibre taken by microscope General Principle Test specimens are analyzed optically • Test specimens can be coated with a layer of and measured using a graduated scale. gold. • The number of fibres from each animal source is determined by observing and identifying them under the microscope. Magnification of Projection-type microscope—500 X 1000 to 10000 X Microscope Transmitted-light microscope—400 X Fibres Scale height Not applicable Cashmere and some of speciality animal fibres: less than 0,55 μm Wool: over 0.55 μm in general Fibres Scale density Refer to AATCC 20A Table I --No. of scales per 100 micron • Cashmere: 6 to 7 • Wool: Under 5.5 Refer to ISO 17751 • Cashmere: 60 scales per mm • Wool: 90 scales per mm Advantage Capable of illustrating internal fibre Topographical features features and pigmentation -cuticle scale edge heights Disadvantage Difficulty may be encountered when -Incapable of describing internal fibre structures attempting the analysis of deeply dyed or -May not be sufficient for the analysis of blends heavily pigmented fibres containing medullated fibres since the medullae Mild dye-stripping or pigment-bleaching will not be visible. procedures may be applied prior to analysis. SGS Cashmere Labs, located in U.K., Hong Kong and Shanghai, are all approved With the experience, qualifications by the “Cashmere & Camel Hair Manufacturers Institute, (CCMI)”. and reputation of our experts, we offer a highly competent analysis service to assure that products meet the labeling regulation. © 2008 SGS. All rights reserved. This is a publication of SGS, except for 3rd parties’ contents submitted or licensed for use FOR ENQUIRIES: rd by SGS. SGS neither endorses nor disapproves said 3 parties contents. This publication is intended to provide technical Global Competences Support Centre: [email protected] information and shall not be considered an exhaustive Ruth Hon +852 2774 7148 or : [email protected] treatment of any subject treated. It is strictly educational and does not replace any legal requirements or applicable regulations. It is not intended to constitute consulting or Asia – Hong Kong. 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