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What additives are used to make polyethylene flexible sheeting?

Polyethylene (PE) is a versatile and widely used polymer that can be processed into various forms, including flexible sheeting. To make polyethylene flexible sheeting, a variety of additives are used to modify its mechanical and physical properties. Here are some of the most commonly used additives for this purpose:

1. Plasticizers: These are low-molecular-weight compounds that are added to polyethylene to increase its flexibility and reduce its brittleness. Common plasticizers used in flexible sheeting include phthalates, adipates, and trimellitates.
2. Slip agents: These are additives that reduce the coefficient of friction between the surfaces of the polyethylene sheets, making them easier to handle and reducing the likelihood of sticking during processing. Examples of slip agents used in polyethylene sheeting include fatty amides, silicone oils, and erucamide.
3. Antioxidants: These are additives that protect polyethylene from degradation due to exposure to heat, light, and oxygen. Common antioxidants used in polyethylene sheeting include hindered phenols, phosphites, and thioesters.
4. Anti-blocking agents: These are additives that prevent the polyethylene sheets from sticking together or to other surfaces, which can occur due to the high surface energy of the material. Examples of anti-blocking agents used in polyethylene sheeting include talc, silica, and diatomaceous earth.
5. UV stabilizers: These are additives that protect polyethylene from degradation caused by exposure to UV radiation from the sun. Examples of UV stabilizers used in polyethylene sheeting include hindered amine light stabilizers (HALS), benzotriazoles, and benzophenones.
6. Colorants: These are additives that add color to the polyethylene sheeting, making it more aesthetically pleasing and helping to distinguish between different products. Colorants can be either organic or inorganic pigments, depending on the desired properties of the sheeting.

Overall, the combination of these additives and their concentrations can be tailored to achieve the desired mechanical, physical, and aesthetic properties of the polyethylene flexible sheeting.

Let's talk about adhesive tape that is touted to stick to plastic sheeting (polyethylene sheeting) that is commonly used in various industrial applications. The tape is designed to adhere to a variety of substrates, including metals, plastics, and other materials. However, in some cases, the tape may not stick well to polyethylene surfaces. There are several reasons why this could happen:

1. Low surface energy: Polyethylene has a relatively low surface energy, which means that it can be difficult for adhesives to bond to it. This can make it challenging for some tapes to adhere to polyethylene surfaces.

2. Surface contamination: If the surface of the polyethylene is contaminated with oils, dirt, or other substances, this can interfere with the ability of the tape adhesive to bond to the surface. Even small amounts of contamination can prevent the adhesive from forming a strong bond.

3. Incompatible adhesive chemistry: Certain fire retardant  tape are designed to work with a range of substrates, but it may not be compatible with all types of polyethylene. If the tape adhesive chemistry is not compatible with the particular type of polyethylene used, it may not adhere well to the surface. When slip or other processing aids are used, they make the surface of the polyethylene more slippery, so it slides through the manufacturing equipment more easily, and can be run much faster.  But it remains on the surface on a microscopic level, and makes it more difficult for tape to adhere well. By nature, the surface of the polyethylene is smooth and slippery, so many tapes do not adhere well, even when no processing aids are used.  

4. Temperature and humidity: The environment in which the tape is applied can also affect its ability to bond to polyethylene. If the temperature or humidity is too high or too low, this can interfere with the curing process of the adhesive, which can prevent it from forming a strong bond. The temperature of the tape when applied also affects the adhesion level. Tape should be applied at room temperature if possible.  The cooler the temperature, the lower the adhesion.  How smooth the finish is for each production run varies depending on temperature and humidity in our manufacturing facility. The smoother the finish,  the harder it is for the tape to adhere.

5. Pressure during Installation: Tape is pressure sensitive.  The more pressure used during installation, the higher the adhesion.  And the adhesion increases as the adhesive wets out on the surfaces being bonded.  The higher the initial pressure, the better the final bond.
   
   
6. Density Range:  The polyethylene has a density range.  At the lowest end of the range it is less smooth than at the highest end of the range. This varies with every batch of resin, and every production run.
   
   
7. The Solution: To improve the adhesion of certain tapes to polyethylene surfaces, it may be necessary to prepare the surface by cleaning it thoroughly and using a primer or other surface treatment to increase its surface energy. Additionally, selecting a different tape formulation or adhesive chemistry may be necessary if the tape is not compatible with the particular type of polyethylene being used.

As you can see, a number of factors may come into play as to why a tape is not sticking to polyethylene plastic sheeting.