Fur Content Testing

Wool content inspection mainly conducts scientific testing and analysis on the total wool content determination, component wool fibre content analysis, special animal fibre identification, blending ratio of wool fibres with the other fibres, and wool fibre damage and quality evaluation, objectively assessing the product quality grade and issuing a detailed test report, providing a basis for manufacturers' quality control and downstream users' product acceptance.

Testing Items

Total wool content determination: This is the most core item of the wool content inspection, aiming to determine the total mass percentage of all the animal wool fibres (such as the wool, cashmere, camel hair, rabbit hair and mohair) in the textile. The testing result is directly related to the raw material cost, pricing strategy and market positioning of the product, and is the important basis for the settlement between the trading parties.

Component wool fibre content analysis: For the blended or spliced products, it is necessary to further analyse which specific types of animal wool fibres constitute them. For example, distinguishing the cashmere from the wool, identifying the Angora rabbit hair and the ordinary rabbit hair, and determining the blending ratio of the cashmere and mulberry silk. This item is crucial for identifying the high-end raw materials and preventing the inferior products from passing off as the superior ones.

Special animal fibre identification: The qualitative and quantitative analysis is specially carried out for the high-value special animal fibres such as the cashmere, yak down, camel hair and alpaca. The identification includes not only the content, but also the confirmation of the fibre types through the microscopic morphological characteristics, cracking down on the adulteration behaviours of passing off the fine wool and modified wool as the cashmere.

Blending ratio of wool fibres with the other fibres: Determines the mixing ratio of the animal wool with the other natural or chemical fibres such as the cotton, flax, viscose, polyester, acrylic and polyamide. For example, the common blended products such as the wool/polyester and cashmere/cotton, whose performance, hand feel and price are closely related to the blending ratio. It is the core technical parameter of the product labelling.

Wool fibre damage and quality evaluation: This item not only pays attention to the content, but also focuses more on the physical quality of the wool fibres. By observing whether the scale structure of the fibre is complete and whether there is the chemical or mechanical damage under the microscope, its strength and crimp are evaluated, thereby judging the influence of the raw materials or processing technology on the quality of the final product.

Testing Scope

Various textile fabrics and yarns: The testing scope covers the woven fabrics, knitted fabrics, nonwovens and the various yarns. Whether it is the worsted wool fabrics, woollen cashmere overcoat cloth or blended wool yarns, the fibre composition content needs to be clarified through the testing, providing the accurate data for the product hang tags.

Finished garments and accessories: Including all the wool-containing garments and accessory finished products such as the overcoats, suits, sweaters, scarves, hats and gloves. The finished product testing needs to consider that the different parts (such as the shell fabric, lining, filling and decorative parts) may use the different materials, and the sampling and analysis need to be carried out separately.

Home textiles and decorative textiles: Such as the wool carpets, cashmere blankets, wool-containing curtains and decorative fabrics. These products are often heavy in structure or specially finished, and the pre-treatment process (such as the yarn unravelling and removal of the finishing agents) is more complex, requiring the higher comprehensiveness of the testing technology.

Industrial wool-containing materials: Including the industrial textiles such as the felt, industrial wool felt and high-grade filter materials. The testing not only determines the wool content, but also needs to evaluate the correlation between the fibre types and the specific functions of the materials (such as the filtration accuracy and thermal insulation performance).

Import and export trade commodities: In the international trade, the wool content is the key indicator for the customs commodity classification, tariff verification and the verification of whether the trade contract terms are met. The testing report is the important legal document for resolving the trade disputes and avoiding the technical barriers to trade.

Testing Methods

Microscopic observation method (physical method): This is the cornerstone method for identifying the types of the natural animal wool fibres. In accordance with the standards such as GB/T 16988 and ISO 17751, a biological microscope or projection microscope is used, and the qualitative identification and manual counting are carried out according to the micro-characteristics such as the scale morphology and medulla layer of the fibre surfaces of the wool and cashmere. The results are accurate but time-consuming.

Chemical dissolution method (quantitative chemical analysis): In accordance with the GB/T 2910 and ISO 1833 series standards, the quantitative analysis is carried out by utilizing the differences in the solubility of the different fibres in the specific chemical solvents. For example, the sodium hypochlorite is used to dissolve the wool, and the 75% sulfuric acid is used to dissolve the cotton and viscose while retaining the polyester. This method is fast and economical, and is the common method for determining the blending ratio of the wool and the other fibres.

Near-infrared spectroscopy analysis method (NIRS): A fast and non-destructive testing technology. By establishing the spectral database models of the samples with the known compositions, the samples to be tested are scanned, and the chemometrics software is used to predict the component contents. It is suitable for the rapid screening on the production lines and the initial inspection of the large batches of samples, but the models need to be continuously maintained and verified.

Scanning electron microscopy method (SEM): When the ordinary optical microscope is difficult to distinguish the fine morphological differences of the fibres, the SEM can obtain the ultra-detection images with the higher magnification and depth of field, and is used to identify the animal fibres that have been deeply chemically treated or are extremely similar. It is an important auxiliary means for solving the difficult identification.

DNA molecular identification method: An emerging cutting-edge testing technology. By extracting the residual animal DNA fragments in the textile, and using the PCR amplification and gene sequencing, the species origin of the fibre is precisely identified. This method can effectively identify the special animal fibres that have lost the morphological characteristics (such as the deeply descaled wool and cashmere), but the cost is high, and it is currently mostly used for the arbitration and scientific research.

Testing Standards

Domestic Standards:

1. GB/T 2910, Textiles — Quantitative chemical analysis

2. GB/T 16988, Quantitative identification of special animal fibre and wool mixtures

3. GB 18401-2010, National general safety technical code for textile products

International Standards:

1. ISO 17751, Textiles — Quantitative analysis of animal fibres by microscopy

2. ISO 1833, Textiles — Quantitative chemical analysis

3. ISO 13934-1, Textiles — Tensile properties of fabrics — Part 1: Determination of maximum force and elongation at maximum force using the strip method

4. ISO 105, Textiles — Tests for colour fastness

Note: The applicable standard can be selected according to the product use and customer trade requirements; standards agreed in the contract take precedence over general standards.

Testing Instruments and Equipment

Biological microscope and projection microscope: The core qualitative identification equipment. The biological microscope is usually equipped with the eyepiece micrometer and polarizing device, used to observe the longitudinal and cross-sectional morphology of the fibres. The projection microscope can project the fibre image onto the screen, which is convenient for the simultaneous observation and counting by multiple people, improving the efficiency and consistency of the manual quantitative analysis.

Routine equipment of the chemical analysis laboratory: Including the analytical balances (accuracy 0.0001 g), constant temperature water bath shakers, vacuum filtration devices, drying ovens and muffle furnaces. These equipment are used to complete the series of chemical treatment steps such as the weighing, dissolution, filtration, drying and ignition in the dissolution method testing, ensuring the precision of the quantitative analysis.

Near-infrared spectrometer: Composed of a light source, spectroscopic system, sample cell, detector and chemometrics software. The instrument needs to be regularly calibrated with the standard samples, ensuring the stability of the spectral data and the accuracy of the model prediction. The probes can be divided into the transmission type, reflection type and diffuse reflection type, to adapt to the samples of the different forms.

Scanning electron microscope (SEM): Composed of an electron gun, electromagnetic lenses, sample chamber, vacuum system and energy spectrometer. When detecting the textile fibres, the non-conductive fibre samples usually need to be sputter-coated with gold or carbon to improve the imaging quality. The SEM-EDS combination can also carry out the element analysis of the fibre surfaces.

DNA extraction and amplification system: Including the tissue grinders (used to break the fibres and release the DNA), nucleic acid extractors, PCR amplifiers, electrophoresis systems and gene sequencers. This set of equipment needs to operate in the specialized molecular biology laboratory, with the extremely high requirements for the environmental cleanliness and the technical skills of the operators, and is used to realize the species-level precise traceability of the fibres.