Definition
The Cobbleness Absorption Tester is a specialized laboratory instrument used to determine the liquid absorption properties of sheet materials such as paper, cardboard, and non-woven fabrics. The instrument quantifies the absorption capacity and rate of materials by simulating the absorption process of liquids under specific pressure and time conditions, providing key data for material development, quality control, and process optimization.
Principle
The core working principle of the instrument is based on fluid penetration and capillary action. During testing, the specimen is placed on an instrument platform with a defined contact pressure applied above it to keep the lower surface of the specimen in contact with a standard liquid, usually distilled water or a specific solution. Within a set time, the liquid is absorbed through the pore structure inside the material. The amount of liquid absorbed by a material per unit area is calculated over a specific period of time by measuring the mass change before and after the specimen absorbs liquid, or by directly reading the absorption displayed by the instrument. Its basic calculation formula is:
C = (m₂ - m₁) / A
where C represents the absorption value (usually in g/m²), m₁ and m₂ are the masses of the specimen before and after absorption, respectively, and A is the effective test area of the specimen.
Measurement method
Standard measurement processes typically follow specifications such as ISO 535, GB/T 1540, or TAPPI T441. First, the specimen is cut to the specified size and adjusted under standard temperature and humidity conditions. The specimen is then placed flat on the test area of the instrument, ensuring that its lower surface is in full contact with the liquid level. After starting the test, the instrument automatically applies the standard pressure and starts timing. Once the predetermined test time (typically 60 or 120 seconds) is reached, the specimen is raised and the surface is quickly removed to weigh its mass using a balance. The absorption value is obtained by calculating the difference. Some automated models can integrate a weighing module and display the results directly.
Influencing factors
The accuracy of test results is influenced by various factors. The characteristics of the material itself are key, including fiber type, porosity, density, sizing degree and surface treatment process. Environmental conditions such as temperature and relative humidity can affect the material's equilibrium, moisture content, and liquid viscosity. In terms of instrument parameters, the contact pressure, the type and temperature of the liquid, the duration of the test, and the contact uniformity of the specimen with the liquid all play a role in the absorption kinetics process. Operational specifications cannot be ignored, such as sample preparation, excess liquid removal method, and weighing speed, all of which need to strictly follow standard procedures.
Applications
This instrument is widely used in the paper industry to evaluate the water absorption properties of toilet paper, facial tissues, packaging cardboard, etc. In the field of nonwovens, it is used to test the liquid retention and transfer capacity of wipes, hygiene product surfaces and filter materials. It is used in the textile industry to determine the absorption of specially treated fabrics. In addition, in scientific research institutions and quality inspection departments, the instrument is also used for performance research and benchmarking analysis of new absorbent materials and composite materials.
Selection considerations
When selecting an instrument, it is necessary to consider the testing needs and compliance with the standards. First, the specific national or international standards to be followed should be clarified to ensure that the core parameters such as the pressure range, timing accuracy, and test area of the instrument match it. Depending on the test throughput, decide on manual, semi-automatic or fully automatic models. The durability of the instrument's material, especially the resistance to corrosion of parts in contact with liquids, affects long-term stability. The data output method, such as whether it has data interface or software support, is related to laboratory information management. In addition, technical support, calibration services and the supply of spare parts from suppliers are also elements to ensure the continuous and reliable operation of the equipment.