In-mold label printing steps

Printing in-mold labeling The printing house that needs special attention should specially designate an in-house technician to contact the blow molding plant, communicate with the blow molding plant in advance, and conduct training in the blow molding process. The technician should be involved in multiple production at the blow molding plant and understand the main requirements of the blow molding process for the label before starting his own printing.

The main steps of printing

(1) Printing of thin films

The use of printed stickers to print in-mold labels is not ideal. In fact, in-mold labels are not more difficult to print than unlabeled labels, but they are only required to use the same type of, similar to the reaction of tension and heat. In spite of the unique force of operation, the effect of their ready-made is worse than that of non-sticky ones.

In-mould film can be printed with the following machine

-UV flexo or letterpress (provide your material supplier with his printing guidelines)
- Sheet-fed Offset It is recommended to use coated in-mold materials that can be used with ordinary oxidizing inks to reduce drying by 4 hours.

- Gravure printing

When printing the in-mold sticker for the first time, absolutely not to tune two parameters at the same time, because the film has tension, change the parameter tension will also change the UV lamp to manual control settings so that the lamp power and heat are not directly with the speed of the printing press Impact.

Inspection points

- Check your printing press: First run on a material with a good texture (such as stickers) and adjust the registration. Check the pressure of the printing roller so it does not slip

- Adjust the speed to normal production speed and adjust the UV lamp. The minimum power, only try to print a color.

- Adjust the tension at a stable production speed (at least the required paper feed tension), check the color shift of the two colors

Record the results you got when you first printed, and make sure you can grasp every improvement. You need to establish a strict production standard with your operators.

Important: The label delivered to the blow molding plant must be free of static electricity or it will cause loss of the target when it is blown.

In general, the in-mold film is subjected to antistatic charges, otherwise the static electricity will be generated in the production process. If your printing press. It is also necessary to install an antistatic device for online die cutting. Electrostatic charges are generated on both sides of the film surface, so it is necessary to install an antistatic device to ensure that the static electricity on the printed surface and the adhesive surface is removed.

Static electricity and varnish: The phenomenon of static electricity generated on varnish is also common. It is recommended to place a destaticizing roller before die cutting and after varnishing. You can also contact your varnish supplier to add antistatic additives to varnish.

(2) Varnish

Varnish is the key that can cause label liftup and stack adhesion.

The label must be free of curling (otherwise, wrinkles or burns on the edge of the label will occur when blowing.)

Blowing plants usually allow certain tolerances for pasted labels, but they should be reduced as much as possible: The label must be tilted to ensure smooth handling of the label.

Tilt: accept the standard

The degree of tilt is proportional to the thickness of the varnish, and also depends on the type of varnish, so a low [shrinkage varnish] should be used.

The door anilox roller should be used:

220 lines/cm15μ thickness 5,5 cm3/m2
275 lines/cm 9 μ thickness 3,3 cm3/m2

Stacking glue

Stacking and sticking are the enemies of in-mold label printing. Therefore, it must be ensured that the lacquer has been dried when it is stacked and will not be spliced ​​during the drying process.

The blown/visco-visced label was an unqualified product because the machine did not dispatch the label.

(Author/Robine)