Problems and solutions in the application of PVC profile protection film

 

The PVC profile protective film is made of a plastic film or an aluminum-plastic composite material, and is coated with a low-viscosity pressure-sensitive adhesive on one side, and is formed into a roll after being cut into a roll. Sticking to the surface of the profile can effectively prevent the surface of the profile from being scratched or contaminated during extrusion, transportation, windowing and installation. Its appearance has brought great convenience to profile production, door and window assembly, and construction units. Since the profile protection film is a relatively new type of product, there is currently no national or industry standard. There is no uniform technical indicator for the quality and testing of products. This brings certain difficulties to the user when choosing to use the protective film. Many profile manufacturers have encountered some problems in the process of use, this article puts forward these issues to discuss with you

 

First, pvc embossed film degumming problem

 

Phenomenon: After the protective film is peeled off from the surface of the profile, a trace of glue remains on the surface of the profile.

 

The main cause of this phenomenon is the quality of the protective film itself. First, the pressure sensitive adhesive used for the protective film does not meet the requirements. There are no technical requirements for formulation and process implementation. The peeling force is greater than the cohesive force; the second is that the corona strength of the substrate used for the protective film is not satisfactory. Generally, the surface tension of the substrate is required to be between 3840 dyn. If it is too small, the peeling force of the protective film is greater than the adhesive force to cause degumming. If such problems occur, it is recommended that the profile manufacturer handle the following: Use a clean cloth to remove an appropriate amount of organic solvents such as ethanol, ethyl ester, toluene, etc. This sometimes causes a problem that the surface finish of the profile will be damaged after being wiped with a solvent. Remedy: Use a soft dry rag to rub a few times to restore the finish.

 

Second, the stickers are not strong

 

Phenomenon: After the profile extrusion film, the film is not strong, and it is easy to peel off during transportation and windowing, and it does not protect. There are several reasons for this:

 

1. Before the film is extruded, the surface is not clean, such as moisture and dust. Improvement method: After the profile is out of the cooling sizing die, try to dry the surface water. Note that the workshop dust is not too much, and the tractor track is kept clean.

 

2, the film machine pressure is not enough, or the structure is not reasonable. Solution: Appropriately increase the film pressure; use a special film machine.

 

3. The viscosity of the protective film is not enough.

 

4. The tensile stress of the substrate used for the protective film is too small, easy to deform, or the rotating part of the filming machine is not flexible, causing the film to be stretched and deformed during the application process. After being applied to the surface of the profile, the film is retracted due to the stress generated by the stretching. When the retracting force is greater than the peeling force, the film is automatically peeled off. For this situation, BOPP, PET or composite protective film with large tensile force can be used instead; in addition, the rotating part of the laminating machine should be lubricated frequently to make it flexible.

 

Third, the two ends are lifted

 

Most of this phenomenon occurs on profiles with aluminum foil film. The main performance is that the protective film at both ends of the profile is lifted. The main reason is: the aluminum foil film in the composite process, the BOPP and PET layer tension is inconsistent, the BOPP layer tension is too large, after the completion of the composite, due to the tension and temperature changes, the BOPP layer is retracted, resulting in lifting. This type of membrane is not recommended for areas with high ambient temperatures and large winds and sands.

 

Fourth, the film is difficult or impossible to uncover

 

Phenomenon: When the door and window were installed, the protective film was removed and it was found that the film could not be peeled off or peeled off.

 

There are two reasons: First, the quality of the pressure sensitive adhesive used in the protective film is unqualified. The pressure sensitive adhesive used for the protective film is a special pressure sensitive adhesive which can form a suitable peeling force with the surface of the product, so that the protective film is easy to apply and easy to peel off. However, many manufacturers have not mastered the production technology of such pressure-sensitive adhesives, but have made some improvements to the pressure-sensitive adhesives for ordinary adhesive tapes, and even used them for the production of protective films without improvement. Of course, the consequences are unimaginable. On the other hand, after the door and window are installed, the ultraviolet radiation in the sunlight is too long, and the protective film substrate is aged, and the strength is reduced and the tear is easily broken. This phenomenon is also caused. Therefore, it is recommended that the construction unit tear off the protective film in time after the decoration of the house is completed.

 

5. Traces of protective film on the surface of the profile

 

Generally speaking, there are two cases: one is that the writing on the surface of the profile is black; the other is that the writing is the color of the word on the protective film. For the first case, there have been articles published in many publications. Most opinions believe that this is a chemical change. This chemical reaction must meet certain conditions to occur: moisture, visible light, unstable TiO2. If the above situation occurs, it is recommended to replace the protective film type or use a PE double-color film or aluminum foil film with good light-shielding properties.

 

For the second case, it is certain that the ink of the protective film migrates. The breakdown occurs in the corona process due to the inner layer of the protective film. After being applied with glue, it is applied to the surface of the profile. After a period of time, the ink will migrate to the surface of the profile through the composite layer and the adhesive layer, causing the writing on the profile. In order to verify this phenomenon, the author has done many tests, selected profiles of different manufacturers, protective film (the same batch of samples that have undergone printing phenomenon) for collocation test, and placed under 250W ultraviolet light for 8 hours, no Printing phenomenon. Later, it was analyzed that the filming conditions during the test were different from those in the production process, and the printing phenomenon reflected by the users occurred on a relatively fixed one or several extrusion equipments, which was not common. The printing phenomenon may have a great relationship with the extrusion process conditions. This problem has not yet found an ideal solution. In this case, it is recommended to use PE two-color film, aluminum foil film, etc.