Definition
A paper water absorption tester is a specialized testing equipment used to determine the ability of paper or cardboard to absorb liquids under specified conditions. The instrument quantifies the water absorption properties of paper by simulating the process of contact with liquids in actual use, providing critical data for material development, quality control, and suitability assessment. Its test methods and results usually follow the relevant technical specifications of international standards organizations and countries.
Principle
The working principle of the paper absorbency tester is based on capillary action and surface wetting effect. The instrument brings the specimen into contact with the test fluid, which penetrates into the paper through the pores between the fibers under specific pressure, temperature, and time conditions. Water absorption is usually characterized by measuring the mass of liquid absorbed by a specimen per unit area or the height of liquid rise, and the basic relationship can be expressed as:
W = (m₂ - m₁) / A
W represents the amount of liquid absorbed per unit area, m₁ and m₂ are the masses before and after the aspiration of the sample, respectively, and A is the effective contact area of the sample. Some test methods also use a time function to record the dynamic water absorption process.
Measurement method
Common measurement methods include impregnation, capillary rise and reblast. The impregnation method completely or partially immerses the specimen in liquid to determine the absorption and weight gain within the specified time; The capillary rise method hangs the specimen vertically, and the lower end touches the liquid surface, recording the change of liquid along the rising height of the paper with time. The Kebo method places the specimen in a ring-shaped metal clamp, touches the liquid surface below, and measures the amount of liquid absorbed by capillary action during a fixed time. During operation, the liquid temperature, ambient humidity, immersion time and sample pretreatment conditions should be strictly controlled to ensure the comparability and repeatability of the results.
Influencing factors
Paper water absorption is influenced by a variety of factors. The material includes fiber type, pulping degree, filler and rubber addition, paper tightness and pore structure; The process involves drying methods, calendering and surface coating. Environmental conditions such as liquid properties, temperature, test time and initial moisture content of the specimen also have a significant effect on the results. Therefore, standard test methods clearly define these variables to ensure the consistency of measurements.
Application:
The instrument is widely used in the paper industry, packaging material testing, printing industry and hygiene products. It is used to evaluate the sizing effect and liquid resistance of paper in paper production. In the packaging industry, it is used to test the moisture resistance characteristics of corrugated cardboard and containerboard; In the printing field, it is used to analyze ink absorption and printability. It is used to control the liquid absorption capacity of products in the research and development of tissue and specialty papers. The test data is of guiding significance for optimizing the production process and meeting user needs.
Selection
When choosing a paper water absorption tester, it is necessary to consider the compliance with test standards, measurement range and accuracy, degree of automation and ease of operation. First, the standard system to be followed, such as ISO, TAPPI, GB, etc., should be clarified to ensure that the instrument structure and function meet the specification requirements. Secondly, the range and resolution of the suction volume or rising height are determined according to the common sample types. Automated features such as automatic timing, level control, and data logging can improve testing efficiency. In addition, the corrosion resistance, safety protection design and maintenance convenience of the instrument material are also aspects that need to be paid attention to in the actual selection.