Oil-absorbing Pad Testing

Sorbent pad testing mainly conducts scientific testing and analysis on adsorption performance testing, liquid retention rate and holding capacity testing, tensile strength and abrasion resistance testing, chemical compatibility testing, flame retardancy testing and pH value 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

Adsorption performance testing: Evaluates the core function of the sorbent pad, i.e., its adsorption capacity for various oils, chemical liquids and water. It is usually quantified by measuring the maximum adsorption amount (grams per square centimetre or grams per gram) of the sorbent pad per unit area or per unit mass for a standard test liquid within a specified time, and is the primary indicator for measuring the effectiveness of the product.

Liquid retention rate and holding capacity testing: Tests the ability of the sorbent pad to hold the liquid without leakage under pressure after adsorbing the liquid. By applying a standard pressure (such as a weight of a certain mass), the amount of liquid squeezed out is measured, to evaluate whether it will cause secondary contamination during handling or use, ensuring use safety.

Tensile strength and abrasion resistance testing: Measures the mechanical strength of the sorbent pad material. The tensile strength tests its ability to resist tensile breakage; the abrasion resistance tests the loss of its surface under repeated friction. These two indicators are directly related to the durability and service life of the sorbent pad in actual use scenarios such as dragging and moving.

Chemical compatibility testing: Checks the stability of the sorbent pad material after contact with specific chemicals (such as acids, alkalis, solvents and oils). By observing whether its structure swells, dissolves, embrittles or significantly decreases in strength, it is determined for which chemical environments it is suitable, avoiding failure or danger caused by material incompatibility.

Flame retardancy testing: For sorbent pads used in industrial places with potential fire sources (such as workshops and gas stations), their flame-retardant characteristics need to be evaluated. Through test methods such as vertical burning and horizontal burning, the burning rate, afterflame time and whether the dripping material ignites the filter paper are determined, to meet the fire safety requirements of specific places.

pH value testing: Tests the acidity and alkalinity of the sorbent pad material itself. Some application scenarios (such as precision instrument cleaning and laboratories) require the material to be neutral, to avoid additional chemical effects on the equipment or the environment. This test ensures that the product will not introduce new contamination risks due to its own acidity and alkalinity.

Testing Scope

General-purpose industrial sorbent pads: Suitable for places such as factory workshops and maintenance stations, used to adsorb common engine oil, lubricating oil, coolant and water stains. Testing focuses on the high adsorption capacity, good abrasion resistance and tear resistance, to meet the demand of high-intensity and frequent use.

Chemical-specific sorbent pads: Designed for specific hazardous chemicals such as acids, alkalis and solvents that may leak in laboratories, chemical plants and during transportation. The testing scope is strictly limited to the chemical categories it claims to be compatible with, and focuses on evaluating its chemical stability, adsorption selectivity and safe disposal requirements.

Oil spill emergency response sorbent pads: Mainly used by the petroleum, port and environmental protection departments to respond to oil spill accidents. Testing focuses on its highly selective adsorption of oils (hydrophobic and oleophilic), high oil retention rate, and the oil adsorption effectiveness and recovery convenience in complex environments such as seawater.

Sorbent pads for laboratories and cleanrooms: Used in clean workshops, biological laboratories, electronic assembly lines and other places with strict cleanliness requirements. In addition to conventional performance, testing particularly emphasizes low dust shedding, no fibre release, ionic cleanliness and sterilizable performance, to prevent particulate contamination.

Civil and commercial sorbent pads: Including garage floor mats, kitchen oil-absorbing pads and pet urine pads. The testing scope covers common liquids in households and commercial places, such as cooking oil, water, detergents and pet urine, and focuses on its convenience of use, appearance and additional functions such as whether antibacterial components are added.

Sorbent pads of special materials: Such as high-performance products made of melt-blown polypropylene, silicone and natural fibre composite materials. According to their unique material characteristics, testing needs to verify the claimed special properties such as the ultra-high adsorption rate, reusability, high-temperature resistance or biodegradability.

Testing Methods

Static adsorption capacity method: A sorbent pad sample of a specified size is completely immersed in a sufficient amount of a standard test liquid (such as engine oil, water or a specific chemical), soaked for a specified time, then hung vertically until no liquid drips out, and the mass difference before and after adsorption is calculated by weighing. This method is used to determine its maximum saturated adsorption capacity, and is a basic and key test method.

Dynamic adsorption rate test method: Simulating the actual leakage scenario, a certain volume of the test liquid is poured on the surface of the horizontally placed sorbent pad, and the time required for the liquid to be completely absorbed is recorded, or the adsorption amount within a specified time is measured. This method can better reflect the rapid response and initial adsorption capacity of the product in actual use.

Liquid retention rate (squeeze resistance) test: The saturated sample is placed between two flat plates, a standardized static pressure (such as 4.5 kPa) is applied and maintained for a certain time, and the squeezed-out liquid is collected and weighed. The liquid retention performance is evaluated by calculating the percentage of the squeezed-out liquid to the total amount of the originally adsorbed liquid.

Tensile strength test (strip method): Referring to the textile or nonwoven test standards, the sample is cut into strips of a specified width, and stretched at a constant rate on a universal material testing machine until breakage. The maximum breaking strength and elongation are recorded, evaluating the mechanical strength and ductility of the material.

Chemical compatibility immersion test: The sample is cut into standard sizes, completely immersed in a specific chemical reagent, and taken out after a specified temperature and time (such as soaking at 23 ℃ for 24 hours or longer). The appearance change is observed, and the weight change rate, dimensional change rate and tensile strength retention rate after soaking are tested.

Flame retardancy test (vertical method): In accordance with the relevant flame retardancy standards, the sample is vertically hung, ignited at its lower edge with a standard flame for a specified time, and after removing the fire source, the afterflame time, afterglow time and damaged length of the sample are recorded. Thereby, whether its flame retardancy grade complies with the corresponding safety specifications is determined.

Testing Standards

Domestic Standards:

1. GB/T 1040.1-2018, Plastics — Determination of tensile properties — Part 1: General principles

2. GB/T 9341-2008, Plastics — Determination of flexural properties

3. GB/T 3682-2018, Plastics — Determination of the melt mass-flow rate and the melt volume-flow rate of thermoplastics

4. GB/T 6672, Plastics film and sheeting — Determination of thickness by mechanical scanning

5. GB/T 1633, Thermoplastic materials — Determination of Vicat softening temperature (VST)

International Standards:

1. ISO 527, Plastics — Determination of tensile properties

2. ISO 178, Plastics — Determination of flexural properties

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

Electronic balance: The high-precision electronic balance is the basic equipment for sorbent pad testing, used to precisely weigh the mass of the sample before and after adsorbing the liquid, to calculate key parameters such as the adsorption capacity and liquid retention rate. It is required that the accuracy reaches at least 0.01 g, ensuring the accuracy and reliability of the data.

Universal material testing machine: Used for mechanical property tests such as tensile strength, tearing strength and bursting strength. This equipment can precisely control the tensile speed and force, automatically record the stress-strain curve, and provide data such as the maximum breaking force and elongation. It is the core instrument for evaluating the durability of the product.

Liquid retention rate tester (or customized pressurizing device): Usually composed of two parallel pressurizing plates, a pressure application system (weights or pneumatic device) and a liquid collection device. It can simulate the real condition of the sorbent pad under pressure after adsorption, quantitatively determine its liquid holding capacity, and prevent secondary contamination.

Chemical stability testing equipment: Mainly including constant temperature immersion tanks (for controlling the temperature of the test liquid), corrosion-resistant containers and related measuring tools (such as vernier calipers for measuring the dimensional change). This equipment set is used to systematically evaluate the compatibility and long-term stability of the sorbent pad material with various chemicals.

Vertical burning tester: Standardized equipment specially used for the flame retardancy testing of textile and polymer materials. It is equipped with a precise burner, specimen holder, automatic timer and safe exhaust system, and can strictly carry out ignition, timing and observation according to the standard procedure, ensuring the comparability and accuracy of the flame retardancy test results.

pH meter: Used to measure the pH value of the extract or the surface of the sorbent pad material itself. After crushing the sample, mixing and shaking it with deionized water for extraction, the acidity and alkalinity of the extract is measured with a calibrated pH meter, to judge whether the product meets the neutral or specific pH range requirements.