Leather Furniture Testing

Leather furniture testing mainly conducts scientific testing and analysis on physical and mechanical property testing, colour fastness testing, coating adhesion testing, pH value and dilution difference, hazardous substance limit testing and flame retardancy 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

Physical and mechanical property testing: Evaluates the durability and strength of the leather and its coating, including items such as tensile strength, elongation at break, tear strength and distension at rupture (ball burst test). These data are directly related to the ability of the furniture leather to resist stretching, tearing and bursting in actual use, and are the key indicators for measuring its service life.

Colour fastness testing: Checks the stability of the leather colour under the action of external factors, mainly including colour fastness to dry and wet rubbing, colour fastness to light and colour fastness to perspiration. For furniture leather exposed to light and human contact for a long time, good colour fastness can prevent colour migration, fading or staining of clothing, and is the core of the appearance retention.

Coating adhesion testing: Determines the bonding strength between the surface coating of the leather (such as the pigment layer and the top finish) and the grain layer of the leather. Using a peeling method with a specified width and angle, it evaluates whether the coating is easy to fall off or delaminate due to bending and scratching, directly affecting the aesthetics and touch of the leather.

pH value and dilution difference: Tests the pH value of the leather extract and its change after dilution at a specified ratio. This indicator is used to evaluate whether the acidity and alkalinity of the leather are moderate, and whether there is a potential risk of "acid damage" or "alkali damage", which is related to the internal chemical stability and long-term preservability of the leather.

Hazardous substance limit testing: In accordance with domestic and foreign regulations (such as REACH and GB 38407), specific hazardous chemicals are controlled, including banned azo dyes, hexavalent chromium, formaldehyde, pentachlorophenol and phthalates. This test ensures that the product is harmless to human health, and is a mandatory requirement for market access.

Flame retardancy testing: For leather furniture in public places or with specific requirements, its ability to resist or delay flame spread needs to be evaluated. The test method usually simulates the contact of a small fire source, measuring parameters such as the afterflame time, afterglow time and damaged length, to meet the relevant safety specifications.

Sensory and marking inspection: Professional personnel judge the appearance quality of the leather such as the grain texture, defects, colour uniformity and hand feel through visual, tactile and other senses. At the same time, the product marking is checked, such as the truthfulness and standardization of information on the leather type (full grain, corrected grain, split leather, etc.), place of origin and implemented standards.

Testing Scope

Division by raw hide type: Mainly including cattle leather (yellow cattle, buffalo and yak leather, etc.), sheep leather (goat and sheepskin), pig leather and other special animal leathers. Different types of leather have significant differences in fibre structure, thickness, strength and hand feel, and testing needs to select the corresponding methods and standards according to their characteristics.

Division by tanning process: Covering chrome-tanned leather, vegetable-tanned leather, aldehyde-tanned leather and combination-tanned leather. The tanning method determines the chemical properties, softness, heat resistance and environmental friendliness of the leather. For example, chrome-tanned leather needs to focus on testing the hexavalent chromium content, while vegetable-tanned leather focuses more on the pH value and resistance to damp heat.

Division by finishing style: Including full grain leather, corrected grain leather, embossed leather, patent leather, suede/nubuck leather and oil wax leather. The finishing process affects the focus of the test items, such as full grain leather emphasizing the natural texture and physical strength, and patent leather focusing on the flexing resistance, abrasion resistance and adhesion of the coating.

Division by furniture component: Testing needs to cover load-bearing and easily frictioned parts such as sofa seats, backs and armrests, as well as headboards and chair surfaces. Different parts have different stress states, and the performance requirements of the leather (such as abrasion resistance and flexing resistance) also have different emphases, and the sampling should be representative.

Division by product life cycle: Covering various stages such as raw materials (wet blue and crust leather), finished leather and finished furniture. Raw material testing controls the incoming material quality, finished leather testing verifies the process stability, and finished furniture testing is the comprehensive verification of the conformity of the final product.

Division by market and regulatory requirements: According to the different sales destinations, testing needs to comply with the corresponding regulatory systems, such as the Chinese national standards (GB), the standards related to the EU CE certification (EN), the standards of the American Society for Testing and Materials (ASTM) and the international standards (ISO), and the testing scope and limits may differ.

Testing Methods

Physical property test methods: The tensile strength and elongation are usually carried out in accordance with ISO 3376 or GB/T 4689.5, using a universal material testing machine under standard temperature and humidity. The tear strength test adopts ISO 3377 (trouser tear method). The distension at rupture test is carried out in accordance with ISO 3379 or QB/T 2710, using a bursting tester to determine the strength of the leather under the compression of a steel ball.

Colour fastness test methods: The rubbing fastness is carried out in accordance with ISO 11640 or GB/T 3920, using a reciprocating rubbing fastness tester, rubbing with dry and wet white cotton cloth respectively under a specified pressure, and rating the staining grade with a grey scale. The light fastness is carried out in accordance with ISO 105-B02, using a xenon arc lamp aging chamber to simulate sunlight irradiation and evaluate the colour change.

Coating adhesion determination method: The ISO 11644 standard is often adopted. A polyester adhesive tape of a specified width is firmly pasted on the leather coating surface, and peeled at a specific angle and speed. The adhesion grade is evaluated by observing the condition of the coating being peeled or measuring the peeling force.

Chemical analysis test methods: The pH value and dilution difference are determined in accordance with ISO 4045. The leather sample is shaken and extracted under specified conditions, and the pH value of the original extract and the pH value after dilution are measured with a precision pH meter. Hazardous substances such as azo dyes and hexavalent chromium are analyzed by instrumental analysis methods such as high-performance liquid chromatography-mass spectrometry (HPLC-MS) and ultraviolet-visible spectrophotometry.

Flame retardancy test methods: Common methods include the vertical burning method (such as GB/T 5455) and the horizontal burning method (such as GB/T 11049). A specimen of a specific size is vertically or horizontally fixed in a combustion chamber, ignited with a specified flame for a certain time, and the flame spread time, speed and damaged length are observed and recorded.

Aging and weather resistance test methods: To evaluate the performance changes of the leather after long-term use, accelerated test methods such as thermal aging (such as ISO 188), flexing resistance (such as SATRA TM31) and artificial weathering aging (such as xenon lamp aging ISO 4892-2) can be adopted, simulating the influence of the actual service environment on the leather.

Testing Standards

Domestic Standards:

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

2. GB/T 5455-2014, Textiles — Burning behaviour — Determination of damaged length, afterglow time and afterflame time

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

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

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

Universal material testing machine: Used to precisely determine the mechanical properties of the leather such as tensile strength, elongation at break and tear strength. The equipment is equipped with high-precision sensors and fixtures, can control the tensile speed, automatically record the force-displacement curve and calculate various results. It is the core equipment for physical property testing.

Rubbing fastness tester: Divided into the linear reciprocating type and the multi-track (Martindale type) type. The former is used for standard rubbing fastness testing, and the latter is more suitable for evaluating the abrasion resistance of the leather surface coating (especially furniture leather), evaluating its durability by counting the number of rubbing cycles.

Bursting tester (ball burst tester): Specially used to determine the bursting strength and distension at rupture of the leather. The instrument uses a steel ball to press the back of the leather specimen fixed in a ring-shaped fixture at a uniform speed until the leather ruptures, recording the maximum load and the pressing height, comprehensively evaluating the strength and extensibility of the leather.

pH meter and oscillating extractor: The pH meter needs to have high precision and temperature compensation functions, and is used to measure the acidity and alkalinity of the leather extract. The oscillating extractor is used to carry out full and uniform extraction of the leather sample under standard conditions (specified liquor ratio, temperature and time), ensuring the representativeness of the chemical test samples.

Gas chromatography-mass spectrometry (GC-MS) and high-performance liquid chromatography (HPLC): These are key equipment for analyzing trace hazardous chemicals in leather. GC-MS is often used to detect volatile organic compounds (such as formaldehyde) and pentachlorophenol; HPLC and HPLC-MS are mainly used to detect non-volatile substances such as banned azo dyes and phthalates.

Xenon lamp weather resistance test chamber and UV aging chamber: Used to simulate the influence of ultraviolet light, visible light and thermal radiation in sunlight on the leather, for light fastness and aging performance testing. The equipment can precisely control the light intensity, black panel temperature, humidity in the chamber and spray cycle, realizing accelerated aging tests.

Flame retardancy testing instrument: Including vertical burning testers and horizontal burning testers. The equipment is equipped with a standard igniter, specimen holder, timing device and a ruler for measuring the damaged length, and is usually placed in a well-ventilated combustion cabinet to ensure the safety of the test process and exhaust gas emission.