Step shell printing film composite process[Buke Printing]

Step shell printing film composite process[Buke Printing]

Soft packaging materials generally do not use a single material, but mainly composite films. The main composite methods are as follows:

(1) Wet composite method

Apply a layer of water-soluble adhesive on the surface of the substrate (plastic film, aluminum foil), composite it with other materials (paper, glass paper) through a pressure roller, and then dry it in a hot drying oven to form a composite film. This method is suitable for packaging dry food.

(2) Dry composite method

First, evenly apply the solvent based adhesive onto the substrate, then send it into a hot drying oven to allow the solvent to evaporate completely, and immediately composite with another layer of film.

(3) Extrusion composite method

The curtain shaped molten polyethylene extruded from the narrow slit of the T mold is pressed by a clamping roller and cast onto paper or film for polyethylene coating, or other films are supplied from the second paper feeding section, and polyethylene is used as a bonding layer for bonding.

Heat and melt polyethylene acrylate copolymer, ethylene acid ethylene copolymer, and paraffin together, and then apply.

(4) Hot melt composite method

On the substrate, it is immediately combined with other composite materials and cooled to form a composite film by extruding various plastic resins with different properties into molds through multiple extruders. This process does not require glue between layers.

(5) Multi-layer extrusion composite method

Adhesive, organic solvent, film odorless, no harmful solvent penetration, suitable for food and pharmaceutical packaging, is an advanced composite technology.

Most of the plastic printing dry composite production lines and domestic composite machines introduced in China use polyurethane adhesives. This adhesive has strong fusion ability for different substrates, excellent cold resistance, heat resistance, oil resistance, dilute acid resistance, and wear resistance,

But it has certain toxicity and cannot be used as an adhesive for inner layer composite. A new type of non-toxic dry adhesive is currently under development, and some achievements have been made in this field in China. For example, APA adhesive is not only non-toxic, but also has better adhesive performance than polyurethane adhesive.

Step shell printing film composite process[Buke Printing]