How can PET film be used in printing?

As PET material plays an important role in variable information printing, it belongs to film printing, and is very different from paper materials in printing process.

1、 Material properties

PET film is a plastic film material with medium and low surface energy. Before printing, surface pretreatment is required to improve the surface removal energy or wetting ability. Otherwise, the fastness of ink and ribbon is not good and they are easy to fall off.

2、 Basic methods of surface pretreatment

a. Corona treatment. The surface energy of the material is increased by means of high-voltage discharge. There are two methods: pretreatment by the supplier when making materials and online processing on the printing machine. The surface tension of the treated film is required to be above 38dyn.

b. Surface coating. Pre coat the material surface with an affinity ink coating, such as corona free PET film surface treatment agent and PET film surface treatment agent, to improve its wetting ability to the ink and increase the firmness of the ink. This treatment method is the most ideal, common and stable method for PET materials.

3、 Printing method

a. Printing and film covering method. Use Xitong offset printing for ink pumping, and cover matt PET or BOPP film for die-cutting immediately after printing. There is no ink drying problem. This kind of processing has no requirements on the surface characteristics of materials. PET or BOPP with matt surface can be printed with ribbon.

B. Printing glazing method. Use UV ink to print online on the rotary label machine and apply UV light varnish. The glazing process can use the entire glazing or partial glazing to reserve the printing position. This method is also commonly used by customers.

c. UV printing. Use UV ink for printing. No film covering or glazing is required, and the printing part is reserved.

d. Printing drying method. Use special oxidation polymerization fast drying special ink, dry it by hot air drying after printing, and finally rewind.

e. Natural drying method. Such labels are usually used for manual labeling, so the processing method is to cut the labels after printing on the reel. The printed label should be put on the shelf naturally after cutting. Similarly, the ink used is a special oxidation polymerization fast drying special ink.

4、 Quality assurance

a. The material surface must be pretreated and meet the standard.

B. The matched special ink, varnish and ribbon shall be tested in advance.

c. Control the thickness of the ink layer and dry it thoroughly. Pay attention to the overprint part of the ink to prevent the ink in the lower layer from drying.

5、 Die-cutting

a. Use a small angle die cutting blade, with a recommended angle of 42 degrees.

b. Use hard die cutting blades made of alloy materials.

c. Keep the blade sharp.

d. Be sure not to die cut the film material again with a die cutter that has cut the paper.

e. Use hard liner and pay attention to flatness, otherwise die cutting quality problems may occur.