Performance Testing of Paper Products
Inaccurate quantitative or strength test data for paper products is the most common problem, which leads to poor precision of the instrument and inaccurate test feedback from customers.In addition to the precision design decision of the machine itself, it is most likely to be caused by the wet lag effect.So what is the hygroscopic effect?
Hygroscopic effect: paper under certain relative humidity conditions by low moisture moisture and reach the balance of moisture content than the same relative humidity by high moisture dehumidification and reach the balance of moisture content is low.Referring to the Tappi T402 standard, the influence of wet lag effect was identified: 5%-25% impact on test performance.As can be clearly seen from the graph of humidity and moisture content in the following figure, for example, 1% moisture lag effect on 6% moisture content is verified by comparative experiment and it is found that 16% test result is affected by this effect.According to GB/T10739 standard atmospheric determination method, under the experimental conditions of 23℃ and 50%RH, a sudden change of 1℃ will bring a change of 3%RH.
So how do you solve the problem of moisture lag?Thermohygroscopic treatment is required -- the process of equalizing the moisture content of the sample between the atmospheres at a specified temperature.Temperature and humidity treatment time: generally 4 hours for good circulation conditions, 5-8 hours for high quantification, 48 hours for high quantification or special materials.The basis for the determination is that the balance is reached when the weighing difference between the samples is no more than 0.25% of the mass of the samples after the two weighing reaches more than 1 hour.
For errors in measurement, repeatability and reproducibility experimental analysis are needed to find out the main factors in order to serve customers and explain the corresponding problems.