When it comes to waste paper pulp in the sticky material, recycled pulp or recycled paper practitioners are familiar with, sticky material is the production of operational stability and product quality of the biggest constraint, so is also related to paper or cardboard production technology personnel most concerned about one of the paper problems.
For the understanding of the adhesive can not only stay in the raw material of the plastic film, hot melt adhesive, wax, and other substances through simple debris removal and thermal dispersion decomposition into the naked eye invisible particles of this superficial level, more need to rise to the relatively advanced adhesive size particles, quantitative analysis, location distribution, and processing methods, so as to be able to truly glue effective control.
Definition of large size adhesive.
Macrostickies generally referred to as sticky particles between 150 and 2000 microns in diameter. Because of its large size particles, insoluble, small density characteristics, this kind of adhesive is relatively easy to remove or handle.
Common treatment methods for large size adhesives are.
1. In the case of OCC slurries, by partial discharge from the drum, preliminary screening by classifying sieves, coarse and fine sieves in combination with removal of larger particles of sticky materials, separation of light impurities under low-concentration conditions in designers, etc..
2. For DIP slurries, partial discharge by the drum, removal of light plastic stickies by compound sieving, removal of larger particles of stickies by coarse and fine sieving, separation of light impurities by deslagger under low-concentration conditions, the capture of stickies by flotation and de-inking, etc..
Common quantitative test methods for large size adhesives.
At present, the most common domestic and international, effective detection of larger particles of the adhesive method is “GB T 21557-2008 determination of adhesive in the waste paper”. This method is mainly applicable to ≥ 100 microns (according to the actual use of vibration sieve size) of the stickies detection and removal.
1. visual method: that is, simply by screening to get the adhesive particles, and then by heating/heating pressure heat fusion to the ink-absorbing paper for heating and heat fusion, and finally by the number of points and the number of size statistics for simple quantification.
2. Image analysis: i.e. screening of the adhesive particles to obtain a special white coating on the surface, transferring them to one side of black cardboard for easy viewing, and finally, quantitative analysis of quantity and area by scanner identification (the GB method is more complex).
But there will be people ask, large size adhesive most commonly caused by paper problems, such as sizing, coating streaks, paper transparent point impurities, local layer bonding caused by poor layering, but the real impact on the operation, the proportion of large particles of adhesive is not intended to be large, but the invisible, invisible microscopic adhesive great impact.
The adhesives can be adsorbed and deposited in the flow system of the paper machine, in the press section, and even in the dryer section, where they are destabilized from their original colloid-like state, causing serious operation problems such as adhesives accumulation on the surface of the wire guide roll and press roll, clogging of the forming net and press felt, butterfly spots on the surface of the dryer section, accumulation of adhesives and paper wool mixture falling from the back of the doctor blade of the dryer section, and adhesives on the surface of the hot roll of the press.
However, do papermakers really understand the microscopic stickies in their paper machine system that really cause system operation problems? Are you still treating the symptoms every time a similar problem arises?
– For example, if you add thermal dispersion once a paper machine glue problem occurs, you will only make the large glue smaller, not take it out of the system at all?
– If there are flakes of sticky material on the back of the cylinder scraper, will you only stop the cylinder or pull out the scraper in line to clean the sticky pieces?
– Once the butterfly spots on the surface of the dryer stick to the broken paper, just replace the copper scraper to clean the surface?
When an industry develops to a certain extent, it must abandon the inherent empirical cognition, and turn to data-based, relatively high-level analysis methods, before getting new technical breakthroughs and higher-dimensional problem solutions.
The analysis and solution of recycled pulp and recycled paper adhesives is precisely a key problem point for today’s paper practitioners who should adjust their thinking, change the existing empirical processing methods, and accept the latest analytical inspection methods!
By using flow cytometry to check and quantify the content and particle size distribution of adhesives ≤100 microns in the white water at various key points in the papermaking process, it can better help us to understand where the adhesives are concentrated and thus effectively control them; on the other hand, it can also efficiently evaluate the changes in the system before and after process optimization (such as adhesives control agents, adhesives enzymes, etc.); most importantly, it can accurately quantify the white water quality indicators during the production cycle, establish an intrinsic link between the content of microscopic adhesives and various types of paper machine operating diseases, and provide accurate and quantitative guidance for process adjustment in daily production.
The “Flow Cytometry – Microscopic Adhesive Testing Service” is available in the Inspection and Testing Unit of the Paper Ring Business Card Shop.
Click on the image below for more information
We help you quantify your data and improve the means and methods of controlling microscopic adhesives with more professional analysis.
Ensure good chemical application and stable paper machine operation!
– Visual representation is more intuitive! (before and after treatment)
– The quantitative expression is more precise!
– Closer operational links
Note: The above image is from the paper “Application of flow cytometry to determine the amount and size of secondary colloid”.