Scientific distribution paper
The physical properties of corrugated boxes are one of the important indicators for evaluating the quality of corrugated boxes. People generally believe that increasing the strength of corrugated boxes will increase their production costs. The author summarizes many years of practical experience and believes that the appropriate increase in the strength of corrugated boxes within a certain range does not necessarily increase their production costs. The following discussion is based on this issue from several aspects for your reference.
The physical properties of corrugated boxes are closely related to their water content. Seasonal changes are evident in most parts of the country, and there are significant differences in temperature and humidity in different seasons. Carton of the same paper, test its physical performance in different seasons, sometimes the test data will differ by about 15%! For this kind of situation, if the cycle of the product is relatively short, can dispose the paper according to different seasons, in this way can avoid damp When the corrugated boxes produced during the season arrived at the normal season, the physical performance indicators of the cartons were far below the standards, causing unnecessary waste.
Different seasons of paper distribution have certain flexibility depending on the price, and carton manufacturers can make appropriate adjustments based on quality assurance. For example, a cardboard box originally used paper: 250A/1 50/250A/1 50/250A and all domestic paper, we can change to 250A/1 50/200B/1 80/250B2 or 250A/1 80/ 200B2/180/K250B2, the paper is also made of domestic paper, the physical properties of the carton using the latter two types of paper way actually close to the former, but the latter two costs are significantly lower than the former.
When we assign paper to a carton, we should not consider that the physical properties of Class B or B2 base paper are definitely worse than the physical properties of Class A base paper. In fact, from the analysis of many years of test data, the physical properties of many Class B or B2 base papers However, the performance of the A-grade base paper is higher than that of the A-grade base paper. The high-grade base paper only has some advantages in printability. Since the core paper and the paper are not directly printed, it is not necessary to print paper suitable for sexual abuse. Of course, not all different grades of base paper can be replaced. When adjusting paper, we must be familiar with the physical properties of various base papers to avoid mistakes.
Corrugated cardboard type change
Under the same production conditions, the use of high-quality corrugating rollers can significantly improve the physical properties of corrugated boxes. Choosing the right corrugated type can also improve the physical properties of the carton. The physical properties of different types of corrugated boxes are shown in Table 1.
According to the results in Table 1, the order of compressive strength and compressive deformation is A>C>B>E. Therefore, the following principles should be followed when designing the carton: If the strength of B-corrugated is sufficient, B-tiles with small deformation are preferentially selected. , and then consider C and A corrugated.
Through the consolidation and collection of corrugated box production data over the years, the physical properties of the A Corrugated Box are sometimes worse than the physical properties of the C Corrugated Box due to various objective factors under the same conditions. The compressive strength is also higher than that of the C corrugated box. Therefore, do not rely entirely on theoretical data when encountering similar situations. It is advisable to make the best choice after testing several types of corrugated board or carton.
Selection of additives in adhesives
At present, in the production of corrugated boxes, in order to increase the compressive strength of the carton, some additives are often added to the binder. The use of appropriate additives can significantly increase the side pressure strength and compressive strength of corrugated boxes. However, the corrugated box side pressure strength and compressive strength are not only related to the degree of adhesion between paper and paperboard, but also related to the use of paper.
It is worth noting that the use of additives is matched with the selected paper properties. If the additives are used improperly, sometimes it will cause serious degumming, which will have a great impact on the compressive strength and side pressure strength of the carton. Therefore, when selecting additives, do the experiment first to avoid batch quality accidents.
Water control in the assembly line
The water content of the corrugated box occupies an extremely important position in the overall performance of the carton, and directly affects the performance indicators of the corrugated box. Therefore, the control of the moisture in the production process is very critical.
In the production process of the assembly line, if the production speed is too high, moisture in the paperboard will not be able to evaporate, which will cause the water content of the paperboard to be too high and the physical properties of the paperboard to be reduced. In this case, the temperature in the production line may be increased or the production line may be lowered. Speed ​​to solve. However, the fact that the paperboard is too dry can also cause problems such as cracking and molding of the paperboard when the paper is formed. How to choose the right process parameters based on different weather and raw material conditions is one of the issues that we should study.
In production, there are many factors that can affect the physical properties of corrugated boxes, such as carton design, printing methods, die cutting and nailing methods, and these factors cannot be changed after the process is determined.
Finally, it is necessary to point out that when taking any measures, we must consider whether the changes will affect the packaging process and safety of the packaged goods.
(author/Lu Liang)
"Printing Technology" corrugated box special issue 2005, 7