Common pre-treatment methods for changing the polarity of plastic surfaces include surface chemical treatment (such as fluorination treatment), surface flame treatment, surface plasma treatment, surface radiation treatment, and so on. These methods each have their own advantages and limitations. We need to consider comprehensively from various aspects such as treatment effect, treatment cost, operational difficulty, environmental friendliness, and industrial production feasibility to choose the most suitable surface treatment method. The following mainly discusses the main differences between plasma surface treatment and flame treatment:

Plasma treatment

Plasma treatment is a surface treatment method that uses plasma state substances to bombard the surface of a substrate, thereby achieving material surface treatment. Plasma treatment is a rapidly developing method in recent years. This treatment method is simple and safe to operate, does not cause environmental pollution, and only undergoes physical or chemical changes in a thin layer of 50-100A on the treated surface, without affecting the intrinsic properties of the material.

Flame treatment

The method of surface treatment of materials using high-temperature flames in a very short period of time is called flame treatment. Flame treatment is a surface treatment method that uses a special flame spray gun to mix a certain proportion of gas and spray the flame onto the surface of polyethylene, causing a sharp increase in surface oxidation components and greatly improving surface wetting ability. The flame treatment method can introduce oxygen-containing groups such as hydroxyl and carbonyl groups on the surface of the material, transforming the weak interfacial layer into a polar surface, thereby improving the adhesion performance. The flame treatment method has relatively simple processing methods and required equipment, and the cost is relatively low, making it currently a more suitable surface treatment method. Its disadvantages are that flame temperature, gas selection, gas flow rate, and the distance between the inner flame (tip) and the material surface all affect the effectiveness of flame treatment. These factors must be carefully selected and strictly controlled to improve the effectiveness and stability of flame treatment.

The main differences between plasma surface treatment and flame treatment

Processing Temperature

The temperature of the outer flame of the flame is very high, and the outer flame temperature of natural gas can also reach 800 to 1800 degrees Celsius. When processing materials, if the outer flame stays on the surface of the workpiece for too long, the workpiece is prone to combustion and accidents may occur. The flame treatment method has the disadvantages of high construction environment requirements and high fire protection level.

Low temperature plasma treatment technology has the advantages of low excitation temperature, high concentration of active particles, and mild modification conditions, making it a current research hotspot in material modification technology. Generally speaking, plasma treatment at temperatures below 200 degrees Celsius will not affect the appearance of the product.

For materials that are not heat-resistant, flame treatment cannot be used.

Shape of processed product

Plasma processing is not limited by the shape of the processed object and can handle materials of various shapes, whether it is the interior of the material such as deep holes or the inner wall, it can be well processed.

Flame treatment has certain requirements for the shape of the product, and for the interior of the product, such as some pores and inner walls, flames cannot be well treated.

Treatment effect

Both flame and plasma treatments can introduce polar hydroxyl and carboxyl groups through oxidation, and the etching effect of surface treatment can remove weak boundary layers and improve surface roughness.

However, flame treatment may cause a decrease in surface smoothness and deformation of curved surfaces due to excessively high temperatures. Therefore, some curved surfaces with poor flame treatment effects can be treated with plasma treatment.

Applicable materials

Plasma treatment can be applied to almost all materials, including metals, glass, rubber, plastics, composite materials, etc., to enhance their surface properties.

Flame treatment is generally applicable for surface treatment of plastic parts. The application range of plasma surface treatment is also more extensive than flame treatment.

The above is a comparison of the main differences between plasma surface treatment and flame treatment. The main differences between the two are explained from four aspects: treatment temperature, shape of the processed product, treatment effect, and applicable materials. In recent years, plasma surface treatment has gradually replaced flame treatment as a new surface treatment method in many industries due to its characteristics of no pollution, no impact on product appearance, and batch processing. Especially in the automotive interior and exterior treatment industry, plasma surface treatment has been widely used.