Method and standard for moisture control of corrugated board and Carton
Method and standard for moisture control of corrugated board and Carton
After the paper received water erosion, corrugated will collapse softening phenomenon, greatly reducing the security of the packaging. However, most people understand that the carton waterproof is only the carton after forming the waterproof problem, but ignored the carton paper moisture content problems. For the control of the moisture content of corrugated board, which aspects should be emphasized?
The purpose of waterproof and moisture-proof corrugated board is actually to maintain the pressure resistance of the carton. After the paper is corroded by water, the corrugated will collapse and soften, which greatly reduces the security of the package. However, most people understand that the carton waterproof is only the carton after forming the waterproof problem, but ignored the carton paper moisture content problems. In fact, control the moisture content of corrugated medium to improve the safety of corrugated box is also crucial. For the control of the moisture content of corrugated board, should focus on the following aspects of control.
1. The moisture content of corrugated base paper should be checked strictly according to gb13023-91 when it comes into the factory.
2. The storage temperature of corrugated base paper should be controlled at room temperature, the relative humidity is not more than 40% .
3. The storage of corrugated base paper should be stacked vertically, the ground should be moisture-proof treatment.
4. Corrugated medium storage time should not be too long. Controlling the temperature and temperature in the production of corrugated board is an important condition for directly adjusting the moisture content of corrugated base paper and ensuring the gelatinization of adhesive. Therefore, when the corrugated board production line is 80m/min ~ 120m/min, the commonly used temperature should be controlled in the range of 160 °C ~ 180 °C, and the saturated steam pressure of the boiler should be controlled in the range of 0.9 MPA ~ 1.2 MPA, this not only can adjust the corrugated medium and single-side corrugated board moisture content, but also to ensure the gelatinization of the adhesive.
In order to ensure the strength of corrugated board and good adhesion, the formation of corrugated board should be based on the different configuration of corrugated board production line necessary adjustments.
1.For the single-sided machine into the corrugated medium moisture content control between 9% ~ 12% corrugated molding is the most ideal. When the moisture content of corrugating medium is higher than the above-mentioned index, it can be solved by increasing the preheating area or reducing the vehicle speed, or by spraying when the moisture content of corrugating medium is lower than the above-mentioned index. The author thinks that the moisture content of the base paper and the corrugated base paper is better adjusted and the moisture content is more suitable when the single-side corrugated paper is fed to the overpass conveyor belt in a positive & type with the same stacking distance, single-sided corrugated cardboard on the bridge pile-up should not be too much, but in order to ensure that the double-sided machine does not stop, in the single-sided paper when the single-sided corrugated cardboard pile-up on the bridge can be appropriately increased.
2.The temperature of the dryer has a great influence on the moisture content of corrugated board. The heating section of corrugated board production line is usually composed of three groups (there are also four groups) , the number of the heating plate is determined by the size of the heating plate and the speed of the corrugated board production line, and each group has its own control valve. In order to ensure that the moisture content of single-side corrugated board is basically the same before entering the dryer, the size of the pre-heating area of single-side corrugated board on the triple preheater can be adjusted. The adjusting method is: When the water content is too high, the preheating area increases; when the water content is too low, the preheating area decreases.
3. Because the corrugated board production process takes away a lot of heat, a part of saturated steam in the preheater and corrugated roller will become condensed water, usually through the drain trap, in order to ensure the normal discharge of condensed water, it is recommended to open the bypass pipe valve before the trap every 4 hours for 3 to 5 minutes to ensure a relatively stable temperature. Control the amount of glue used to make corrugated board is usually corn starch adhesive, its main ingredients are: Corn Starch, water, sodium hydroxide and Borax, because of the different configuration of corrugated board production line, its speed is different, the prepared adhesive viscosity, concentration, gelatinization temperature is also different. With the size of the glue, the moisture content of corrugated board also changes. When gelatinize quantity is big, the moisture content of corrugated board is big, vice versa is small. For single-sided machine and double-sided machine, the gap between coating roller and limiting roller is generally 0.2 mm ~ 0.25 mm, for single-sided machine, the gap between corrugated roller and coating roller is generally 0.1 mm ~ 0.2 mm. Double-sided Press Roller (contact Rod) and coated roller gap should be slightly less than the single-side corrugated cardboard height 0.05 mm ~ 0.1 mm M. The gap can be measured with a plug gauge, but the two rollers should be parallel to each other.
