Release paper is used in many industries today. As a used person, it is not always possible to choose a suitable release paper. Today, Xiaobian will discuss with you some common problems already exist. For many years, there are already relatively reliable ways to prevent and resolve them. This section is dedicated to explaining the causes of these common problems and providing some advice to avoid or correct them.


1, film reverse transfer


When the adhesive is not on the correct side of the substrate, the film reverse transfer occurs; due to the peeling of the adhesive, unwinding may occur. The reverse transfer of the film may be caused by the following factors: adhesive bleed, uneven moisture content, improper winding tension, insufficient curing or release force of the release material is not wide enough.




2, foaming / blisters


Foaming is a phenomenon of damage on the surface of substrates, coatings, adhesive coatings, and the like. Foaming typically occurs when liquids such as water or organic solvents, or gases such as air, swell faster than the entire system is capable of dissipating its increased volume and pressure. For example, if the double-sided PEK release paper is heated to an excessively high temperature, the PE will soften, and when the vapor pressure of the moisture in the paper is sufficiently high, bubbles will form in the PE, also for releasing the pressure.


Foaming can be caused by the following reasons:


- overheating


- The penetration/dissipation of the liquid/vapor components of the system is limited


- Evaporation of solvent or water


The following practices can minimize bubbles:


- lower the maximum temperature


- Reduce heating rate


- Use a breathable, water permeable, release material


3, adhesion


When the layers of the release material are fused together, it is difficult to unwind without damaging the paper or using high unwinding tension, at which point adhesion has often occurred. Adhesion may only occur on a certain part of the paper such as the edge, or a whole sheet of paper, and can be caused by many different mechanisms.


- Insufficient curing of silicone oil


- uneven moisture content


- Excessive winding tension


- chemical pollution


- Insufficient release force


There are many different ways to prevent it:


- Increase the degree of cure


- Reduce environmental humidity and improve storage conditions


- Reduce tension by reducing press roll pressure, increasing winding tension taper or reducing torque


Many people also use noise as an indicator of adhesion. This method is very subjective and does not determine adhesion because of the inherent "slip" or "adsorption" properties of certain coatings.


4, delamination


Delamination means that the layers that are mechanically or chemically bonded together are separated at the interface. Delamination can occur at the interface of the PE with the paper or at the interface of the adhesive with the silicone oil.


Usually delamination is a problem with materials and interfaces. For example, delamination of PEK coated release paper is due to poor surface treatment before PE coating. The delamination of the adhesive may be due to the silicone oil being too easily peeled off.


Delamination may be caused by the following reasons:


- Improper flame or chemical surface treatment.


- Internal adhesion difference


- poor internal bond between fibers


- Improper release force of silicone oil coating (too light)


The delamination can be corrected by the following methods:


- Improve surface treatment


- Improve the internal bonding of the substrate


- Increase the release force of silicone oil coating