What are the current surface treatment technologies for BOPP synthetic paper?

At present, the surface treatment technology of BOPP synthetic paper (that is, bidirectional polypropylene film) mainly includes the following:

1. Corona treatment

How it Works:

Corona treatment is to apply high frequency and high voltage to the processing device to make its corona discharge and produce small and dense sparks. These sparks ionize the air, creating various low-temperature plasmas. These plasms accelerate the impact on the surface of plastic products under the action of strong electric fields, induce the chemical bond of the plastic surface molecules to break, form free radicals, and then oxidize and cross-link with the plasma, so that the film surface produces polar groups, increasing the surface roughness. At the same time, the corona discharge process will also produce ozone, ozone as a strong oxidizing agent, will further oxidize the plastic surface molecules, improve the surface tension.

Advantages:

Corona treatment is simple and easy, good treatment effect, is widely used by film manufacturers.

It can significantly improve the wettability and adhesion of the plastic surface, and meet the needs of subsequent processing such as printing and composite.

Influencing factors:

Processing power: The greater the power, the greater the surface tension is usually, but the effect may no longer be obvious after a certain degree.

Film temperature: As the film temperature increases, the surface treatment value will increase accordingly.

Production line speed: The change of speed will affect the residence time of the film between the plates, and the electrode voltage needs to be adjusted accordingly.

Exhaust air volume: The amount of exhaust air will affect the ozone concentration, and then affect the surface treatment effect.

Surface material: The surface tension of polypropylene homopolymer and copolymer after corona treatment is different.

Electrode type: Compared with single electrode, double electrode can produce higher processing value at the same energy consumption, and has other advantages.

2. Flame treatment

How it Works:

Flame treatment is to melt or oxidize the surface of the plastic through the high temperature of the flame, thereby changing its surface properties. This method can rapidly improve the roughness and wettability of the plastic surface, but compared with corona treatment, its operation complexity and environmental control requirements are higher.

Applications:

Because flame treatment is more difficult to operate in practical applications and the control accuracy is not as good as corona treatment, the use of flame treatment in the production of BOPP films is relatively small. However, in some special needs, such as the need for extremely high surface roughness or a specific surface chemical structure, flame treatment is still a viable option.

3. Other surface treatment techniques

In addition to corona treatment and flame treatment, there are a number of other surface treatment techniques available for BOPP synthetic paper, such as:

Chemical treatment: by soaking, spraying and other ways to apply chemical agents on the surface of the plastic to change its surface properties. This method requires precise control of chemical concentrations and treatment times to avoid damage to the plastic body.

Mechanical treatment: such as grinding, sandblasting and other mechanical methods, can increase the roughness of the plastic surface, but may introduce scratches or damage, affecting the overall performance of the product.

Plasma polymerization: The polymerization reaction is carried out in a plasma environment to form a polymer film with a specific function on the surface of the plastic. This method can precisely control the thickness and properties of the film, but the equipment cost is high and the process is complex.

In summary, corona treatment is the most commonly used and effective method in the surface treatment of BOPP synthetic paper. Other methods are selected and applied according to specific needs and conditions.