How to ensure the adhesion between the coating and the paper base during the production process of PE coated cup paper roll?

In the production process of PE coated cup paper roll, it is very important to ensure good adhesion between the coating and the paper base. Good adhesion can not only ensure the effectiveness of functions such as waterproof and oil-proof, but also extend the service life of the paper cup and prevent the coating from falling off or being damaged. The following are some common methods and techniques to improve the adhesion between the PE coating and the paper base material:

1. Surface treatment (surface pretreatment)
Corona Treatment: Through high-frequency corona discharge treatment, polar functional groups are generated on the surface of the paper base to increase the activity of the surface. This treatment will increase the surface tension of the paper base, thereby enhancing the adhesion of the PE coating. Corona treatment can improve the affinity between the coating and the paper base, especially during the coating process, effectively improving the uniformity and stability of the coating.

Plasma Treatment: Similar to corona treatment, plasma treatment also changes the surface structure of the paper base through discharge to produce high-energy molecules. This method can effectively improve the adhesion of the paper base surface, especially for more special coating requirements.

Chemical treatment: By using surfactants or adhesives, the paper base surface is chemically modified to improve its adhesion to the PE coating. This method is usually used in combination with other treatment methods to ensure the improvement of coating adhesion.

2. Coating process control
Control coating temperature and humidity: During the coating process, maintaining appropriate temperature and humidity can effectively affect the adhesion of the PE coating to the paper base. The coating temperature needs to be precisely controlled to ensure that the PE coating can be more closely bonded to the paper base material. If the temperature is too low, the coating may not be fully adhered; if the temperature is too high, it may cause the coating to cure too quickly, thus affecting adhesion.

Coating rate and coating amount control: Control of coating rate and coating amount is critical. Too fast coating may result in uneven coating and reduced adhesion; too slow coating may result in too thick coating, thus affecting the flexibility of the paper cup. The ideal coating rate and coating amount can ensure that the coating is uniform and firmly bonded to the paper base.

3. Hot press curing (hot press treatment)
Hot press curing: After coating, the use of hot press curing process can effectively promote the bonding of the coating to the paper base. During the hot pressing process, the interface between the coating and the paper base is enhanced in adhesion through the action of heat and pressure. This process can reduce the risk of coating shedding and improve the durability of the coating.

4. Choose the right PE coating material
Choice of low-density and high-density PE materials: In the coating process, it is also very important to choose the right PE material. Low-density PE (LDPE) and high-density PE (HDPE) have different coating properties. The former is usually softer and can better blend with the paper base, while the latter has higher permeability resistance and strength. According to the needs of the product, choosing the right PE material can further improve the adhesion.

Use of additives: Adding appropriate additives, such as tackifiers or adhesives, to the PE coating can enhance the adhesion between the coating and the paper base. By optimizing the ratio of additives, the adhesion of the coating can be improved without affecting the performance of the coating.

5. Control the quality of the paper base
Surface flatness of the paper base: The surface quality of the paper base directly affects the adhesion of the coating. A paper base with a rough surface and many impurities is prone to cause the coating to adhere loosely. Therefore, the quality of the paper base should be strictly controlled during the production process to ensure that its surface is flat and free of impurities.

Moisture content control of paper base: The moisture content of paper base has a certain effect on the adhesion of coating. Too high moisture content may lead to weakened adhesion of coating. Therefore, controlling the moisture content of paper base within a suitable range is crucial to ensure the bonding between coating and paper base.

6. Coating curing and drying
Appropriate curing and drying time: After coating, ensuring the complete curing of coating is an important link to ensure adhesion. PE coating needs to go through a proper curing process after coating, which usually involves heating or using ultraviolet curing. Only after the coating is completely dry can it ensure its strong bonding with paper base.

7. Quality inspection and control
Online inspection system: Through high-precision online inspection system, the thickness, uniformity and adhesion of coating are monitored in real time. These inspection systems can detect defects or unevenness of coating in time, ensure the stability of production process and consistency of products.

Adhesion test: By conducting adhesion test (such as peel test), it can be ensured that the bonding between coating and paper base meets the standard requirements. The test results can be fed back to the control link in the production process for adjustment and optimization.

8. Cooling and stabilization
Control of cooling process: The cooling process after coating is equally important. Too fast cooling may cause the coating to shrink and crack, which in turn affects the adhesion. By controlling the cooling rate and ensuring the stable solidification of the coating, the coating can be effectively prevented from falling off.

To ensure good adhesion between the PE coating and the paper base in the PE coated cup paper roll, it is necessary to accurately control the surface treatment, coating process, hot pressing curing, selection of coating materials, paper base quality and other links during the production process. Through refined process control and quality inspection, the bonding strength between the coating and the paper base can be effectively improved, thereby ensuring that the final product has good waterproofness, oil resistance and overall performance.