Fiber cleanliness usually refers to the degree of purity of fibers after removing impurities such as dust, oil, pesticides, chemicals, etc. The cleanliness directly affects the performance, comfort, and appearance quality of textiles. For example, fibers with poor cleanliness can affect the dyeing uniformity, strength, hand feel, and breathability of textiles. For high-performance fibers, especially in the fields of medicine and special applications, cleanliness requirements are more stringent because impurities may have a serious impact on the functionality, comfort, and safety of the product.
The standards for fiber cleanliness vary depending on the application field, fiber type, and relevant industry specifications. According to the different uses of fibers, standards also vary. For example, the cleanliness requirements for ordinary clothing fibers are relatively low, while medical textiles, filter materials, etc. have more stringent cleanliness requirements.
In order to accurately measure the cleanliness of fibers, various testing methods have been adopted in the industry. Different detection methods have their own advantages and disadvantages, and choosing the appropriate detection method is crucial for ensuring fiber quality.
1. Weight method
Principle: The weight method determines impurity content by measuring the weight difference before and after fiber cleanliness. The basic principle of this method is to process the fiber sample under specific conditions (such as removing oil, impurities, etc.), and then measure the change in weight before and after.
Steps:
1. Take a certain weight of fiber sample.
2. Clean or remove impurities from the sample.
3. Measure the weight difference of the sample before and after processing.
4. Calculate the impurity content in the fiber based on the weight difference.
2. Microscopic method
Principle: The microscope method determines the cleanliness of fibers by observing impurities on the surface and inside the fibers. This method is suitable for fibers with obvious impurities, especially under high-power microscopes, where fine impurities on the surface or inside of the fibers can be clearly observed.
Steps:
1. Take fiber samples and perform simple processing (such as removing surface oil, etc.).
2. Place the sample under a microscope for observation.
3. Record the quantity, type, and distribution of impurities.
4. Evaluate the cleanliness of fibers by observing the size and distribution of impurities.
3. Chemical analysis method
Principle: Fiber is treated with chemical reagents to dissolve or decompose impurities in the fiber, and then the type and content of impurities are determined. This method is particularly suitable for detecting chemical pollutants such as oils, dyes, pesticides, etc.
Steps:
1. Select a certain amount of fiber samples.
2. Use appropriate chemical reagents to process the sample to dissolve or decompose impurities.
3. Determine the type and concentration of impurities through chemical analysis (such as spectroscopic analysis, liquid chromatography, etc.).
4. Calculate based on the concentration of impurities.
4. Gas chromatography (GC)
Principle: Gas chromatography determines the cleanliness of fibers by analyzing the content of volatile components in them. This method is commonly used to detect volatile pollutants such as oil and solvents in fibers.
Steps:
1. Extract volatile components from fibers.
2. Use gas chromatography to analyze the types and concentrations of components in the sample.
3. Calculate the impurity content based on the results.
5. Infrared spectroscopy (FTIR)
Principle: Infrared spectroscopy analyzes the chemical composition and impurities in fibers by measuring the absorption of infrared light of different wavelengths by the sample. This method can identify various types of impurities in fibers, including oils, dyes, plastic particles, etc.
Steps:
1. Prepare fiber samples and perform pre-treatment.
2. Use Fourier transform infrared spectrometer to analyze the sample.
3. Analyze the types and concentrations of impurities through spectrograms.
Currently, there are various methods for detecting fiber cleanliness, including gravimetric analysis, microscopy, chemical analysis, gas chromatography, and infrared spectroscopy, each with its own advantages. Choosing appropriate testing methods and standards can help the textile industry more accurately evaluate the cleanliness of fibers and take effective measures to improve the cleanliness level.