Ecological Board Testing

Ecological board testing mainly conducts scientific testing and analysis on key performance indicators and other items, objectively assessing the product quality grade and issuing a detailed test report, providing a basis for manufacturers' quality control and downstream users' product acceptance.

Core Testing Items

Formaldehyde emission: This is the most critical environmental indicator of ecological boards. According to the national standard, it is mainly determined in accordance with GB/T 39600-2021 "Classification of formaldehyde emission of wood-based panels and their products", divided into E1 grade, E0 grade and ENF grade. Testing usually adopts the chamber method, the desiccator method or the gas analysis method, to precisely quantify the formaldehyde concentration released into the air per unit time of the board, ensuring that the product meets the indoor use safety requirements.

Surface bonding strength: This indicator is used to evaluate the firmness of the bond between the decorative layer (such as impregnated paper film) and the substrate (such as particleboard and fiberboard). In accordance with standards such as GB/T 17657-2022, a vertical tensile force is applied to the specimen through a specific device until the glue layer fails, and the maximum failure load is recorded. Excellent bonding strength is the basis for ensuring that the board surface is abrasion-resistant, scratch-resistant and does not peel or detach.

Modulus of rupture: The modulus of rupture reflects the ability of the board to resist bending deformation and fracture under vertical loading, and is the core indicator for measuring its structural load-bearing performance. During the test, the two ends of a rectangular specimen are simply supported, and a load is applied at a uniform speed at the center point until fracture, and the maximum failure stress is calculated. This indicator directly affects the compression and deformation resistance of cabinets and tabletops made from this board.

Internal bond strength: Also known as the planar tensile strength, it is used to evaluate the firmness of the bond between the fibers or particles inside the board. During the test, a tensile force is applied in the thickness direction of the specimen through dedicated fixtures until it is pulled apart. Insufficient internal bond strength will cause problems such as delamination and blistering of the board during processing or use, and is the key to judging the quality of the substrate.

Moisture content: The moisture content of the board directly affects its dimensional stability, physical and mechanical properties and subsequent processing quality. Testing usually adopts the gravimetric method, drying the specimen at a specified temperature to constant weight and calculating the moisture content from the mass difference before and after drying. Too high moisture content tends to cause deformation and mold growth of the board, while too low may make it brittle.

Surface scratch resistance: This item evaluates the ability of the board decorative surface to resist scratching by sharp objects. In accordance with the standard, a scratch needle of a specified hardness is used to apply a specific load for scratching, and the visibility of the scratches is observed and rated. This performance is directly related to the aesthetic retention and durability of furniture in daily use.

Surface stain and corrosion resistance: Simulating daily life scenarios, the resistance of the board surface to common pollutants (such as coffee, vinegar, lipstick and shoe polish) is tested. The pollutant is placed on the surface and covered, and after the specified time it is removed. It is observed whether phenomena such as discoloration, blistering, cracking or gloss change occur on the surface, to evaluate its ease of cleaning and durability.

Testing Standards and Scope of Application

GB/T 39600-2021 Classification of formaldehyde emission: This standard is currently the basis for the environmental performance of ecological boards in the domestic market. It clearly divides the formaldehyde emission into E1 grade (≤0.124 mg/m³), E0 grade (≤0.050 mg/m³) and the highest environmental grade ENF grade (≤0.025 mg/m³), applicable to the formaldehyde emission testing and grading of all wood-based panels and their products.

GB/T 34722-2017 Impregnated paper film surfaced plywood and blockboard: This standard is a product standard specifically for ecological boards with plywood and blockboard as the substrate (commonly known as "multi-layer solid wood ecological board"). It specifies in detail the terms, classification, requirements, test methods, inspection rules and marking, packaging, transportation and storage of such products.

GB/T 15102-2017 Impregnated paper film surfaced fiberboard and particleboard: This standard is a product standard specifically for ecological boards with fiberboard (density board) and particleboard as the substrate. It covers the technical requirements, physical and mechanical properties (such as modulus of rupture, internal bond strength and surface abrasion resistance) and appearance quality inspection methods of the products.

GB/T 17657-2022 Test methods of evaluating the properties of wood-based panels and surface decorated wood-based panels: This is the basic general test method standard in the wood-based panel field. Most of the physical and mechanical property testing methods and part of the chemical property testing methods of ecological boards, such as moisture content, density, water absorption thickness swelling, surface abrasion resistance and surface cigarette burn resistance, need to be carried out with reference to this standard.

GB 18580-2025 Indoor decorating and refurbishing materials — Limit of formaldehyde emission of wood-based panels and finishing products: This is a national mandatory standard, specifying the formaldehyde emission limit requirements (E1 grade is the market access bottom line) and test methods of indoor wood-based panels and their products. All ecological boards sold in the domestic market must comply with this standard.

Scope of applicable products: The test items and standard system described in this report are widely applicable to various decorative boards made with wood-based panels (including particleboard, fiberboard, plywood and blockboard) as the substrate, with impregnated paper film applied on the surface and formed by hot pressing, i.e., the "ecological boards" or "melamine surfaced boards" commonly known in the market.

Main Testing Methods and Principles

Chamber method (formaldehyde testing): A specimen of specified surface area is placed in a climate chamber with constant temperature, humidity and air exchange rate. After the formaldehyde released by the specimen mixes with the air in the chamber and reaches equilibrium, the air in the chamber is extracted and the formaldehyde concentration is analyzed through a chemical absorption solution or a chromatograph. This method simulates the formaldehyde release state of the board in the real indoor environment, gives the most accurate and reliable results, and is the arbitration method.

Desiccator method (formaldehyde testing): The specimen is placed at the bottom of a desiccator, with a crystallizing dish containing distilled water placed above to maintain humidity. After sealing, it is placed at a certain temperature for a specified time. The released formaldehyde is absorbed by the distilled water in the upper part of the desiccator, and then the formaldehyde content in the absorption solution is determined with a spectrophotometer. This method is relatively simple to operate and is often used for internal quality control of factories.

Universal mechanical testing machine (physical property testing): This is the core equipment for mechanical tests such as modulus of rupture, internal bond strength and surface bonding strength. Through a precision servo control system, precisely controlled tensile, compressive and bending loads can be applied to the specimen, and the force change is recorded in real time by sensors, and various strength indicators are automatically calculated in combination with the specimen dimensions.

Surface performance comprehensive testing instrument: An integrated device that can usually carry out various tests such as surface abrasion resistance, scratch resistance, stain resistance and cigarette burn resistance. By replacing different test modules (such as rotary grinding heads, scratch needles and heating heads) and setting parameters such as load, rotational speed and time according to the standard, a comprehensive evaluation of the durability of the board surface decorative layer is realized.

Gravimetric method (moisture content testing): The most classic and direct method for determining moisture content. A balance with an accuracy of 0.01 g is used to weigh the initial mass of the specimen, which is then dried in an oven at (103±2) ℃ to constant weight and its oven-dry mass is weighed again. The precise moisture content is obtained by calculating the percentage of the difference between the initial mass and the oven-dry mass relative to the oven-dry mass.

Spectrophotometric method (chemical analysis): A key chemical method for quantitative analysis of the formaldehyde concentration in the absorption solution or extraction solution in the desiccator method or the perforation extraction method of formaldehyde emission. The principle is that formaldehyde reacts with reagents such as acetylacetone or AHMT under specific conditions to generate a colored compound, which has maximum absorption at a specific wavelength. By determining the absorbance and comparing it with the standard curve, the formaldehyde concentration can be calculated.

Testing Instruments and Equipment

1 m³ VOC emission climate chamber: The core equipment for carrying out the formaldehyde emission chamber method test in the GB/T 39600 standard. The chamber body is made of inert material, with precise internal control of temperature (23±0.5 ℃), relative humidity (50±3%), air exchange rate (1.0±0.05 times/h) and air flow velocity, and is equipped with a high-precision formaldehyde online analyzer or sampling system, ensuring accurate and reliable data.

Electronic universal material testing machine: Equipped with various dedicated fixtures (such as three-point bending fixtures, internal bond strength fixtures and surface bonding strength fixtures), it is used to precisely determine mechanical indicators such as modulus of rupture, modulus of elasticity, internal bond strength and surface bonding strength. Its high-precision load sensors and displacement sensors can completely record the force-displacement curve during the test.

Surface abrasion testing machine (Taber type): Used to evaluate the abrasion resistance of the ecological board surface decorative layer. The specimen is rubbed by two grinding wheels of a specific model on a rotating platform. By setting the number of rotations, the mass difference before and after abrasion is measured or the number of revolutions required for the surface to be worn through is observed, thereby rating its abrasion grade and simulating the wear condition in long-term use.

Constant temperature and humidity chamber: Before testing, it is used for the conditioning of specimens so that they reach the temperature and humidity equilibrium state specified in the standard (usually temperature 20±2 ℃ and relative humidity 65±5%). All physical and mechanical property tests must be carried out on conditioned specimens to ensure the repeatability and comparability of the test results.

Precision drying oven and analytical balance: The drying oven is used for drying the specimens in the moisture content determination, requiring precise and uniform temperature control. The analytical balance needs to have an accuracy of 0.01 g or higher, and is used to weigh the specimen mass before and after drying, which is the basis for calculating the moisture content, density and the mass loss of some abrasion resistance tests.

Spectrophotometer: An instrument used to determine the absorbance of solutions in chemical analysis. In formaldehyde testing, it is used for colorimetric analysis of the absorption solution after the chemical color development reaction, and directly reads out or calculates the formaldehyde concentration in the sample through the built-in standard curve or calculation formula. It is key equipment for quantitative analysis.

Thickness gauge and vernier calipers: Used to precisely measure the basic dimensions such as the thickness, length and width of the specimen. These dimensional data are the necessary input values for calculating almost all physical performance parameters such as density and strength (strength calculation is related to dimensions), and their measurement precision directly affects the accuracy of the final test results.