Under the premise of guaranteeing the adhesive strength of the board, the steam pressure should be reduced as much as possible, and the steam pressure can be reduced from the usual 9~11kgf/cm2 to 7~8kgf/cm2. In this way, the surface temperature of the heating element such as the preheating cylinder can be reduced, the water loss of the corrugated cardboard during the production process can be reduced, and the folding resistance of the cardboard can be improved.
Reduce the heating of the board during the production process. For a single-sided unit, the intake valve of the preheated cylinder and the preheated cylinder on the single-sided machine can be properly closed according to the specific conditions of the base paper to reduce the intake air amount. For a double-sided machine, the intake valve of part of the hot plate may be closed or the amount of intake air of the hot plate may be reduced, and the height of the gravity roller of the hot plate of the double-sided machine may also be appropriately increased.
In the case of ensuring the normal adhesion of single-sided corrugated cardboard, the sizing amount of the single-sided machine and the steam spray of the core paper should be appropriately increased.
Increasing the running speed of the double-sided machine and reducing the running time of the cardboard in the double-sided machine can also reduce the heating amount of the cardboard, reduce the loss of moisture, and improve the folding-resistant degree of the cardboard.
Spraying: Spraying device is installed between triple preheater and double-sided machine to spray single-sided corrugated board to increase water content. At the same time, it is also possible to install a spray device at the slitting press line to cause the paperboard to dry before pressurizing due to the shutdown of the double sided machine, so as to increase the moisture content of the paperboard so that the paperboard will not break easily when the paper is pressed.
Pressure line: try to deepen the depth of the pressure line, so that the cardboard does not break to the limit, so that the cardboard "to crack not cracked" to ensure that the cardboard is pressed through, compacted, corrugated must be collapsed, this can significantly improve the carton flap The degree of folding.
Reducing the viscosity of the glue and increasing the water content of the glue can increase the water content of the board. The viscosity of the glue is recommended to be controlled between 30 seconds and 35 seconds.
Doing the above points will have a significant effect on improving the folding resistance of the board.
Ultra-thin corrugated cardboard
The ultra-thin corrugated cardboard includes E corrugated, F corrugated, and G corrugated, and it has become a revolutionary product of the corrugated cardboard industry. In 1998, the output value of ultra-thin corrugated board accounted for about 8% of the total output value of corrugated board. It is expected that it will continue to grow in the next five years. In particular, G Corrugated will replace 10% of the market for cardboard (such as ash-white paper) in the next five years. In particular, cartons exceeding 400 g/m2 will be replaced by ultra-thin corrugated cardboard.
In 1998, there were 30 sets of G-type corrugating rollers in Europe and 25 sets in the United States. In 1999, another 50 G-type corrugating rollers were installed one after another.
When producing ultra-thin corrugated cardboard with a conventional corrugated board production line, the following factors should be taken into account:
Raw paper force control
Stable and high-speed take-up machine
Dual original paper force control system
The glue and gluing equipment (a) The glue formula should be suitable for high-speed car ultra-thin corrugated board light weight heavy plate wide paper use.
(b) The gap between the corrugating roll and the top roll must be controlled to 0.01 mm. The pressure shoe roll (glue) clearance adjustment system should be considered.
Bridge Tension Control (a) The use of the flyover guides of the German E&L company and the tension control system of BHS are preferred.
(b) Low basis weight paper is suitable for production of ultra-thin corrugated cardboard.
Double tile machine: Thermal control BHS Bartrol Double tile machine (a) Hot plate area: Most of the reason for the paperboard bending is the temperature, and the gravity roller needs to be automatically adjusted according to the paper width and production speed.
(b) Cooling zone: pressure plate type.
Cross cutter: The ability to cut in short sizes, 245mm/min. (500mm long)
Base paper:
(a) Lightweight heavy paper with 80~135g/m2 facial paper
(b) Average moisture control and base paper thickness control
How to prevent the cardboard from bending back (a) tension (b) heating control (c) glue control
Reproduced from: China Corrugated Machinery Equipment Network
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