From a technical point of view, the most frequently encountered problem in the application of wet chemicals is that it does not achieve the desired effect, Paper Making Chemical resulting in a failure of the paper machine test or replacement of the product. There are three main reasons for this, first, the modern paper industry has a great diversity, from raw materials to equipment, from technology to management, Paper Making Chemical different paper machine has a great difference, one or several products are difficult to meet the different needs of most paper machine; second, due to market competition, paper-making enterprises continue to adopt a variety of new paper machine and paper machine for paper-copying process, which makes many paper-making process has a strong particularity, general application and problem-solving experience and methods are often not applicable; third, In the paper machine test or application process of the product, Paper Making Chemical there will inevitably be such or such problems.
Because of the continuous production of paper machine characteristics, once the problem often needs to be resolved immediately, in this case, there is often not enough time to adjust to achieve the best application effect of the product.
Retention agents are the most susceptible to the problem of wet-part chemicals, mainly because retention agents affect the underlying factors of paper pages, that is, Paper Making Chemical the interweaving of paper pages. Retention agent through retention can affect the entire paper-making process.
The most common problem in the application of retention agent is to make the paper evenness worse. At present, all retention agents rely on flocculation mechanism (flocculation and condensation), and the result of flocculation is to form Floc, when flocculation is too strong, the paper evenness will become worse. Therefore, Paper Making Chemical when the retention agent is applied, the molecular structure, dosage and adding method of retention agent need to be controlled. Most of the retention agents have the function of filtration, and the effect of flocculation on the evenness can be counteracted to some extent by improving the water filtration of the pulp.
In order to produce effective retention effects, at least one product in the retention agent system should be an organic flocculant of high molecular weight. When using solid flocculants, Paper Making Chemical the solubility of the product is very important. Flocculant is widely used, and different uses have different requirements for the solubility of the product. For example, the flocculant used for paper-copying must have very low insoluble content, the flocculant for wastewater treatment is not high, the speed of modern large-scale papermaking machine is more and more fast, so it is necessary to use macromolecule flocculant to resist the high shearing force in the process of pulp flow and forming. The solubility of the product is more important when the polymer mass flocculant is used. Too much insoluble material in the product will cause difficulty in paper-copying.
Pigments, which are similar to paper fillers, Paper Making Chemical do not form an effective chemical bond with the fibres, so they need to be retained in the paper on the wet part. When pigment retention is not good, the preserved pigments circulate in the wet part of the white water and eventually form a stain on the paper.
Some dye products in long-term storage will occur concentration uneven phenomenon, if the use of the product is not stirred evenly, the upper layer of the lower concentration of dye into the paper-copying system, will make the amount of dye increased significantly. Most of the dyes used in the wet part are negatively charged, some even with a strong negative charge. If the dye dosage is high or the addition point is too close to the cationic wet chemical, it is possible to affect each other, resulting in color spots or reduce the use of product effects. Paper Making Chemical It is usually necessary to maintain a certain distance between the adding points of dyes and cationic chemicals.
Neutral and alkaline paper widely used AKD and ASA synthetic sizing agent. These two kinds of sizing agent will occur during the white water cycle hydrolysis, in the paper machine wet, pressing and drying of the front of the sediment, causing a sticky cylinder, or even paper. Asa Hydrolysate was originally in the form of free acid in the pulp, when the ASA Hydrolysate encountered calcium carbonate in the pulp, free acid will be converted into calcium salts, Paper Making Chemical dissolved, thus deposited. Therefore, the presence of calcium is often found in the analysis of ASA Hydrolysate.