Do you know why the stretch film needs to be added with additives? Now Zhiteng will answer this question for you!

1. Compatibility

Poor compatibility will cause "migration" phenomenon, which is "sweat" in liquid additives and "blooming" in solid additives.

Sometimes when the requirements for stretched film are not too strict, some lack of compatibility can be allowed, such as poor compatibility between filler and resin. As long as the filled particle size is small, it can still meet the basic requirements of stretched film performance. If it is treated with a coupling agent or surfactant, its function can be better played. However, there are some additives that improve the surface properties of the stretched film, such as an antistatic agent and an antistatic agent, which require a little bit of mobility to make it work on the surface of the stretched film.

2. Durability

The auxiliary agent is required to exist in the stretched film for a long time and there is little or no loss. The loss of the auxiliary agent is mainly through three ways: volatilization, extraction and migration. This is mainly related to the molecular weight of the additives, the solubility in the medium and the solubility in the resin.

3. Processing conditions

The processing conditions of some special resins for stretch film are harsh. If the processing temperature is high, it should be considered whether the selected additives will decompose and whether the additives have corrosive effects on the processing equipment.

4. Use of stretch film

Stretch films for different purposes have different requirements for additives such as odor, toxicity, weather resistance, and thermal properties. For example, plastic bags for food are required to be non-toxic, so the additives used are different from those of general packaging plastic bags.

5. Synergistic and opposing effects in the combination of additives

In the same resin system, some of the two additives will produce "synergistic effect". If it is not properly matched, some additives may have a "reverse effect", which will weaken the function of each additive, or even make it lose its effect. For example, the combination of carbon black and phenolic antioxidants will have an antagonistic effect.