What are the requirements of stretch film for foam materials

Stretch film is the use of physical foaming instead of chemical foaming, in the foaming process needs to use a material is foaming agent, in the production process for the choice of foaming machine and temperature control is relatively strict. Because only in this way can a qualified product be produced:
(1) First of all, it is required to be gaseous in the standard state and easily liquefied under pressurized conditions, because the foaming of the stretch film is the result of the transformation of the physical foaming agent from the liquid state to the gaseous state;
(2) Secondly, the foaming agent is required to be colorless, odorless, non-toxic, non-rotten, no residue in the polymer after foaming, low permeability in the polyethylene melt, low vapor pressure, high volatility, low molecular weight and high density at room temperature;
(3) The gas cost per unit volume is low, it can be dissolved in polyethylene in the extruded state, the temperature and pressure are increased, the change in solvency will increase, and it is easy to foam into a foam with very small density.
The foaming agent used in the stretch film needs to be carried out under strict regulations, according to a certain principle of operation, if it is an unqualified product, there will be many problems in use, so in order to better avoid, we must make corresponding preparations.