The role of three-roll nip type coating compound machine for flexible packaging

DATE:2019/10/25 9:06:12 / READ: / SOURCE:This station

The role of three-roll nip type coating compound machine for flexible packaging
The three-roll nip type coating machine for flexible packaging has many functions:
(1) Usually a low basis weight or extensible substrate (film)
(2) It can provide a short or long extruder die position relative to the nip to achieve a better bond between the die exit polymer and the substrate
(3) It can be used with different rubber hardness to contribute to the resulting adhesion. The rubber roller is also undercut from time to time to prevent the edge material from sticking to the rubber roller.
(4) The hanging glue of a small diameter roller should be saved more than the cost of the large diameter roller.
The cylinder of the rubber roller is pressed and the cooling roller forms a nip. In the double roll nip configuration, the diameter of the rubber roller must be large to reduce deflection. The larger the diameter of the rubber roller, the greater the embossing formed in the nip under pressure. Embossing can tension most substrates, especially for substrates that cannot be extended, such as foil and paper, which can cause the web to break. Therefore, when coating or compounding foils, films and low-grade papers, it is recommended to use rubber rolls with smaller diameters, higher hardness (90-95 Shore A hardness), and steel water-cooled backing rolls to have Helps reduce the deflection of small diameter rubber rollers.
The coating compound machine operating section is typically the most important part of the extrusion coating line, which determines the processing speed of all remaining transmissions in the production line. The main component of such a coating compound machine is a cooling roll whose size is determined by the amount of heat that must be removed from the polymer exiting the die, in terms of kilojoules per hour per 100 mm wide web surface. The chill roll (where the press roll is at its "3 o'clock") must be very effective in transferring heat from the polymer-coated substrate to the take-off roll (this position is at the "11 o'clock" of the chill roll). The polymer is removed. Depending on the temperature of the extruded polymer used and the selected extrusion ratio, the polymer coated substrate should be cooled to about 45 ° C to allow the polymer coated substrate to be directed away from the chill roll. Failure to reach this temperature may cause the polymer coated substrate to continue to wrap around the chill roll, causing the web to break, resulting in downtime and waste.

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