Postpress Technology 1000 Questions (74-82)

74. What is the content of the coating film discharge operation?

Discharging refers to adjusting the surface state of the BOPP film before gluing. The process is that the BOPP film is passively rotated and conveyed on the discharge rack, and successively passes through the splicing mechanism, the drying mechanism, and the hot pressing mechanism to form the flattening rollers and the arched bending rollers.

75. What is the content of the glue dispensing operation of the coating film?

Before gluing, according to the technical requirements of the configuration of the appropriate concentration of glue, such as a solvent-based adhesive to add O. 3 to 1 part of solvent, and 1 part of emulsion adhesive should be added to O. 1~O. 3 parts water.

76. What is the coating operation of the coating film?

Before gluing, the thickness of the gluing layer of the gluing mechanism must be set, calculated, and tested, and the thickness of the gluing layer adjusted and locked. Before the official coating, the speed of the gluing mechanism must be adjusted and locked. Different prints with different numbers of prints have different requirements for adhesives and coating thicknesses. The binder concentration and thickness must be set to ensure that all types of prints require binder dry basis, as shown in Table 6. Then, pressure is applied to press the film against the applicator roller to force the film to “wipe away” the glue on the applicator roller to complete the transfer of glue from the applicator roller to the film.

77. What is the content of the glue drying operation of the coating film?

The glued film passes through the drying tunnel, allowing the solvent in the adhesive to evaporate as much as possible.

78. What is the content of the printed product conveying operation of the coated film?

According to the paper thickness, size and other conditions to adjust the rules. Cut off the edges of the film wider than the paper print.

79. What is the hot pressing operation of the coated film?

The main unit of the heat sealing mechanism and the heating device are started so that the heating roller reaches a set temperature of 50°C to 65°C. Start the manual oil pump and control the pressure at 8~15MPa/m2 to set the main engine speed. Film and adhesive composites with paper prints through the hot-press cooperation zone.

80. What is the winding operation content of the coating film?

Start the winding mechanism motor and adjust its rotation speed; adjust the winding tension control speed; wind the composite semi-finished product into a coil.

81. What is the storage operation of the coating film?

Place the coiled composite semifinished product in an appropriate environment for storage.

82. What is the content of the slitting operation of the coated film?

The slit film product is slit into pieces according to the required size.

Source: "Guangdong Printing" (author / Jin Yinhe: Beizhuang Institute of Graphic Communication)