Corrugated board adhesive bonding and automatic line speed temperature

The adhesive strength of the paper puller is an important indicator of the physical properties of the paper. The quality of the paper puller is related to the quality of the whole carton. Because a large part of the cartons produced by the automatic line are used for export packaging, and the goods are loaded into the cartons, they must be stored, transported, transported, and transported for a long period of time such as stacking and jolting. It is not uncommon for cartons to fester and pressure collapse due to poor adhesion. This not only causes damage to cartons manufacturers and exporters, but also affects our country’s external noise. Therefore, how to improve the adhesive strength of the cardboard is an important issue for us who have automatic line manufacturers. We analyze the causes of the effects of adhesion, and consider that the speed and temperature of the automatic line are two more important factors.
The bonding process of cardboard involves complex physical and chemical changes. It depends not only on the nature of the adhesive, but also on various conditions. The properties of the adhesive include viscosity, pH, and gelatinization. Temperature and other indicators, the size of this indicator directly affect the bonding strength of the cardboard, so when we make adhesives, we should do:
1, suitable viscosity.
2, the appropriate concentration.
3, the viscosity change should be small.
4. Good initial adhesion.
5, no precipitate.
6, make the cardboard hard.
Based on the above points, we should strictly follow the operating procedures and process requirements in the production of adhesives, taking into account various environmental impact factors, in order to ensure the quality of cardboard bonding. Therefore, when we study the relationship between the following adhesion and speed and temperature, we can assume that the adhesive is in compliance with the requirements, which is more conducive to the analysis of the relationship between them.
(A) The relationship between adhesion and speed 1. The bonding of single-sided corrugated cardboard in a single-sided machine, and the process of adhesion of starch granules in the adhesive is:
Water Absorption - Swelling Wetting - Destruction - Dispersion - Dehydration - Curing (macromolecular chain formation).
If the speed of the single-sided machine is too fast, the amount of corrugated paper will be reduced, and the width of the coating will be narrow, which will affect the adhesion effect.
If the speed of the single-sided machine is too slow, not only will the amount of glue applied be increased, but the starch adhesive will also be hardened due to an excessively high temperature and the adhesive effect will be lost.
2, the relationship between the speed and adhesion of the double-sided machine The double-sided machine is the combination of single-sided corrugated cardboard with the paper, the bonding is the key to the entire paperboard bonding, speed control is good, not only will make corrugated, face paper Good compounding will also make up for the adhesive defects of single-sided corrugated cardboard. Conversely, if the control is not good, the entire paperboard will be poorly bonded.
If the speed of the double-sided machine is too fast, the amount of glue applied to the paper and corrugated paper will be reduced, and the amount of heat will be too low, so that the starch will not be gelatinized, resulting in poor adhesion.
If the speed of the double-sided machine is too low, the amount of glue applied to the paper and corrugated board will increase, the heat will be too high, the structure of the starch will be destroyed, and the adhesive structure of the single-faced corrugated board will be destroyed, causing the board to burn.
(b) The relationship between adhesion and temperature is shown in the following table, which is the relationship between the temperature, speed, and vapor pressure of the automatic line (see Table 1).
Table 1

Steam pressure (kg/cm2) Speed ​​(m/min) Temperature (°C)
6.0 30 158
6.5 35 161
7.0 40 164
7.5 50 167
8.0 60 170
9.0 80 176
10.0 100 179
12.0 150 or more 187

When the corrugated board is recombined on a double-sided machine, since the first group of hot plates ensures high temperature bonding, and the second and third groups are used to dry and stabilize the cardboard, how to adjust the temperature of the three groups of heating plates is very good for the bonding effect. The important role.
If the temperature of the double sided machine is too high, the adhesive has already gelatinized in a very short time, and excessive drying is performed on the hot plate at other times. This will cause excessive drying of the paperboard. In production, generally, only the production of three This happens only when the cardboard is in layer. Therefore, if high speed operation is not possible due to other conditions, several sets of heating plates should be turned off or turned down.
If the temperature of the double-sided machine is relatively low (cannot be lower than 155°C, ie, the pressure cannot be lower than 5kg), so that the board runs on the double-sided machine, it takes a long time to reach the adhesive paste, and the board cannot be fully baked. Dry, such as cardboard with high water content, not only affects the adhesion, but also causes warpage and low thickness. Therefore, when this happens, the production rate should be high or low.