Bonding of three corrugated cardboards with production speed and temperature
The adhesive strength of corrugated cardboard is an important indicator of the physical properties of corrugated cardboard. The bonding process of corrugated cardboard involves complex physical and chemical changes. It depends not only on the quality of the adhesive but also on various conditions. Physical and chemical indicators of the adhesive include viscosity, pH, gelatinization temperature, solid content and other indicators. Changes in these indicators directly affect the adhesive strength of corrugated cardboard. Although there are other aspects of the bond strength, the quality of the bond itself is the dominant factor. Therefore, when making adhesives, you should do the following:
1. The quality of raw and auxiliary materials used must be guaranteed
2. Accurate measurement of raw and auxiliary materials when feeding
3. Use good water quality as much as possible
4. Ensure the proper temperature of the production environment and the site
5. Ensure proper viscosity
6. Ensure proper concentration
7. The finished adhesive has no precipitate
8. Finished adhesives have little change in viscosity during storage and use
9. Ensure good initial viscosity and permeability in the production process
In accordance with the above principles, in the production of adhesives, strictly in accordance with operating procedures and process requirements, taking into account the impact of various factors to ensure the adhesive effect of corrugated cardboard.
The good adhesion should be that the adhesive coated between the corrugated corrugated paper and the tissue paper is rapidly gelatinized after high-temperature baking, and the paper and the adhesive are firmly combined. When the adhesive is peeled off by special equipment and accessories, the adhesive should be torn. It is the fiber of the paper and should not be peeled off by the adhesive.
Adhesives used in single-faced corrugating machines primarily control the solids content, gelatinization temperature, and viscosity of the adhesive during the formulation process.
Solid content refers to the content of starch, caustic soda, natural rubber-specific desiccant, and borax in the binder. It mainly refers to the amount of starch. The content of starch is high, and the solid content is high. Adjusting the clearance of the rubberizing roller during use can increase the speed of the vehicle, increase the output, and facilitate drying. The solid content of the formulated adhesive is preferably about 20% of the total amount of the adhesive.
The gelatinization temperature refers to the critical temperature at which the binder is cooked and cooked. When the gelatinization temperature of the binder is low, less heat is consumed in the production process, which can increase the speed of the vehicle.
Viscosity refers to the adhesive's ability to flow during production. We require low viscosity of the adhesive, in fact, in order to have good fluidity in use. It can increase the initial adhesion. Preparing the cooked slurry is the key to controlling the viscosity of the adhesive. First, we must strictly control the mixing time, when the mixing time is not enough, the viscosity of the adhesive is not stable; Second, we must master the ratio of caustic soda and other raw materials. Only a good grasp of the relative relationship between the solids content of the adhesive, the gelatinization temperature and the viscosity can produce good quality adhesives, thus ensuring good adhesion in the production process.
In the production process, the viscosity of starch glue is proportional to the temperature and the amount of caustic soda. In use, the viscosity of starch glue is inversely proportional to temperature and stirring speed. In order to avoid that the viscosity of the glue is reduced too quickly during use, the colloid circulation and the temperature increase should be minimized (for example, the gear pump of the circulation system can be changed to an air pump and the large cycle can be changed to a single cycle).
1. The viscosity of one-side machine and three-layer line production adhesives is controlled at 20--50 seconds.
2. Production of adhesives for the production of five-layer and seven-layer adhesives is controlled for 50-90 seconds. In special cases, the adhesive viscosity is adjusted according to requirements.
Relationship between speed of cardboard production line and steam pressure and temperature (see table)
Normal align=center>speed (m/min)
Normal align=center>Vapor pressure (MPa/cm2)
Normal align=center>Temperature (°C)
Normal align=center>30
40
50
60
80
100
150
Normal align=center>0.6
0.7
0.75
0.8
0.9
1
1.2
Normal align=center>150
160
165
170
175
180
185
One-sided corrugating machine speed is too fast, to take into account the amount of glue on the peak of the corrugated tile, at this time the binder solid content requirements are high, otherwise affect the adhesion effect.
A single-faced corrugator locomotive speed is too slow and will increase the amount of rubber on the peak of the corrugated tile. At the same time, due to the slow speed, excessive temperature will cause the adhesive to prematurely solidify and lose its good adhesion effect, even by hand. The shoot will open.
If the speed of the double-sided locomotive is too fast, the amount of glue on the peak of the corrugated tile will be reduced. At the same time, due to the excessively high speed, the heat consumption will increase, the temperature will decrease, and the adhesive will not be gelatinized well, resulting in poor adhesion.
If the speed of the double-sided locomotive is too low, the peak amount of corrugated corrugated paper will increase, the temperature will accumulate, and the corrugated board will be excessively baked, so that the adhesive structure will be destroyed and the corrugated board will become brittle.
(to be continued)