Printed and Dyed Fabric Testing

Printed and dyed fabric testing mainly conducts scientific testing and analysis on colour fastness testing, physical property testing, dimensional stability testing, fabric structure and composition analysis, appearance quality inspection and ecological safety performance testing, 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

Colour fastness testing: This is the core item for measuring the quality of printed and dyed fabrics, mainly evaluating the adhesion stability of the dyes on the fabric. Common tests include the colour fastness to rubbing, colour fastness to soaping, colour fastness to perspiration, colour fastness to light and colour fastness to water. These tests simulate the daily use and washing conditions, and the fading and staining grades are assessed through the standard grey scales. The higher the grade, the better the colour fastness.

Physical property testing: This item focuses on the durability and retention of the fabric. It mainly includes the breaking strength, tearing strength, bursting strength and abrasion resistance tests. These indicators directly affect the service life and wearing experience of the garment, and the tests need to be carried out in accordance with the standard methods under the specified temperature and humidity environment, to ensure accurate and comparable data.

Dimensional stability testing: Used to evaluate the degree of the dimensional change of the printed and dyed fabric after washing, dry cleaning or steaming, and is the focus of garment processing and consumer attention. The test methods include the dimensional stability after washing, after dry cleaning and after steaming, assessed by measuring the warp and weft length change rate of the fabric sample before and after washing or treatment.

Fabric structure and composition analysis: Including the determination of structural parameters such as the fabric density, yarn count, mass and fabric weave, as well as the qualitative and quantitative analysis of the fibre composition. Accurate composition analysis is the basis of the product labelling, pricing and subsequent processing technology, and means such as microscope observation, chemical dissolution method or infrared spectroscopy are usually adopted.

Appearance quality inspection: Under a standard light source cabinet, visual inspection is carried out on the printed and dyed fabric to evaluate its appearance defects. The main items include colour difference, weft skew, streaks, colour spots, stains and holes. The inspection is carried out in accordance with the appearance defect scoring provisions in the national or industry standards, to determine the grade of the product.

Ecological safety performance testing: With the increasingly strict environmental protection regulations, this item is becoming more and more important. It mainly tests the hazardous substances such as prohibited azo dyes, formaldehyde content, pH value, heavy metal content, chlorinated phenols and phthalates. The test results need to meet the requirements of the domestic and foreign mandatory or voluntary standards such as GB 18401 and Oeko-Tex Standard 100.

Functional testing: For printed and dyed fabrics with special functions, special tests need to be carried out. For example, the hydrostatic pressure resistance and spray rating tests of waterproof fabrics, the vertical burning or limiting oxygen index tests of flame-retardant fabrics, the UPF value test of UV-resistant fabrics, and the verification of properties such as moisture absorption and quick drying and antibacterial performance.

Testing Scope

Classification by fibre raw material: Covering the fabrics of natural fibres such as cotton, linen, wool and silk, the fabrics of chemical fibres such as polyester, nylon, acrylic and spandex, and the blended or interwoven fabrics of various natural and chemical fibres. For printed and dyed fabrics of different fibre raw materials, the testing methods and indicator emphasis are different.

Classification by fabric weave: Including woven fabrics of basic weaves such as plain, twill and satin, such as poplin, khaki and gabardine; and various knitted fabrics, such as single jersey, interlock and rib fabrics. There are significant differences between woven fabrics and knitted fabrics in the physical property test methods (such as tensile and bursting).

Classification by printing and dyeing process: Including dyed fabrics (such as all-cotton dyed fabrics and polyester-cotton dyed fabrics), printed fabrics (such as reactive printing, digital printing and transfer printing) and yarn-dyed fabrics. The testing focus of products of different processes varies. For example, printed fabrics need to additionally pay attention to the printing fastness and pattern definition.

Classification by final use: The testing scope covers apparel textiles (such as shirts, coats and underwear), home textiles (such as bed sheets, curtains and sofa fabrics) and industrial textiles (such as advertising fabrics and flag fabrics). Products of different uses follow different standard systems. For example, apparel emphasizes comfort and safety, and home textiles emphasize durability and beauty.

Classification by trade and regulatory requirements: Including domestic products meeting the Chinese national standards (GB), and export products complying with the international standards (such as ISO and AATCC), EU regulations (such as REACH) and the requirements of the US Consumer Product Safety Commission (CPSC). The testing scope needs to be dynamically adjusted according to the regulations of the target market.

Classification by product life cycle stage: The scope runs through the incoming inspection of raw materials, the quality control in the production process, the ex-factory inspection of finished products, and even the market supervision spot checks and the arbitration inspection of consumer complaints. The testing purpose and sampling plan of each stage are different.

Testing Methods

Standard test methods: The testing of printed and dyed fabrics strictly follows the recognized standard methods at home and abroad. China mainly adopts the GB/T national standard series, and internationally the ISO (International Organization for Standardization), AATCC (American Association of Textile Chemists and Colorists), EN (European Standards) and JIS (Japanese Industrial Standards) are widely adopted. When selecting the methods, the product use and target market need to be considered.

Colour fastness test methods: For the colour fastness to rubbing, GB/T 3920 or ISO 105-X12 is commonly used, using a rubbing fastness tester; for the colour fastness to soaping, GB/T 3921 or AATCC 61 is commonly used, using a standard soap solution and a laundering fastness tester; for the colour fastness to light, GB/T 8427 or AATCC 16 is commonly used, using a xenon arc lamp or carbon arc lamp fading machine to simulate sunlight exposure.

Physical property test methods: The breaking strength and elongation test adopts the strip method (GB/T 3923.1) or the grab method (GB/T 3923.2), using a constant rate of extension strength tester. For the tearing strength, the tongue method (GB/T 3917.2) or the trapezoid method (GB/T 3917.3) is commonly used. For the bursting strength, the steel ball method (GB/T 19976) is commonly used.

Composition analysis methods: The qualitative analysis of the fibre composition can adopt the microscope method, combustion method, dissolution method and infrared spectroscopy method. The quantitative analysis mainly adopts the chemical dissolution method (GB/T 2910 series), using the difference in the solubility of different fibres in specific chemical reagents for separation and calculation.

Ecological safety test methods: The prohibited azo dyes testing adopts GB/T 17592, and the carcinogenic aromatic amines are analysed by gas chromatography-mass spectrometry (GC-MS) after reductive cleavage. The formaldehyde content determination commonly uses the water extraction method (GB/T 2912.1). The pH value determination adopts the water extraction method of GB/T 7573. The heavy metal testing mostly uses instruments such as inductively coupled plasma mass spectrometry (ICP-MS).

Functional test methods: In the waterproof performance testing, GB/T 4744 is commonly used for the hydrostatic pressure resistance and GB/T 4745 for the spray rating. In the flame retardancy testing, GB/T 5455 is commonly used for the vertical method. The UV resistance test adopts GB/T 18830, measuring the UV transmittance by the spectrophotometer method and calculating the UPF value.

Testing Standards

Domestic Standards:

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

2. GB/T 3920-2024, Textiles — Tests for colour fastness — Colour fastness to rubbing

3. GB/T 3921-2008, Textiles — Tests for colour fastness — Colour fastness to washing with soap or soap and soda

4. GB/T 8427-2019, Textiles — Tests for colour fastness — Colour fastness to artificial light: Xenon arc fading lamp test

5. GB/T 3923.1-2013, Textiles — Tensile properties of fabrics — Part 1: Determination of breaking force and elongation at breaking force using the strip method

International Standards:

1. ISO 105, Textiles — Tests for colour fastness

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

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

Colour fastness testers: Including rubbing fastness testers, perspiration fastness testers, laundering fastness testers, water spotting fastness testers and weathering colour fastness testers. These instruments can simulate and standardize various external action conditions, and are the key equipment for evaluating the dye stability. Advanced weathering instruments can precisely control the light, temperature, humidity and spray.

Electronic fabric strength tester: Used to test the mechanical properties of the fabric such as tensile, tearing and bursting. Modern strength testers are mostly computer-controlled, can automatically record the load-elongation curve, precisely calculate indicators such as the breaking strength, elongation and work, and have multiple test fixtures to adapt to different standard methods.

Standard light source cabinet: Provides standard light sources such as D65, TL84, CWF and UV, providing a stable, uniform and reflection-free lighting environment for the visual assessment of the colour difference, the fading and staining grades of the colour fastness and the appearance defects. It is essential equipment for eliminating the influence of environmental light and ensuring the consistency of the inspection results.

Fabric thickness gauge and mass balance: The thickness gauge is used to measure the fabric thickness under a standard pressure. The precision electronic balance is used to determine the mass per unit area (mass). The combination of the two can calculate derived parameters such as the bulkiness and density of the fabric, and is the basis of the fabric structure analysis.

pH meter and extraction device: Used to determine the pH value of the aqueous extract of the printed and dyed fabric. The equipment includes a precision pH meter with temperature compensation, a shaking water bath or mechanical shaker and glassware. The precise pH value test is crucial for evaluating the acid and alkali residues of the fabric and whether it meets the ecological standards.

Precision analytical instruments: Mainly used for ecological safety testing. Including gas chromatography-mass spectrometers (GC-MS) for the analysis of prohibited azo dyes and pesticide residues; inductively coupled plasma mass spectrometers (ICP-MS) or atomic absorption spectrometers (AAS) for the trace heavy metal analysis; and high-performance liquid chromatographs (HPLC) for the separation and determination of various hazardous substances.

Dedicated functional testing equipment: Such as hydrostatic pressure testers (for measuring the waterproof performance), vertical burning testers (for measuring the flame retardancy), UV transmittance analysers (for measuring the UV resistance), air permeability testers and moisture management testers. These equipment can quantitatively evaluate the special function claims of the printed and dyed fabric.