The square or rectangular polymer web formed by stretching may be uniaxially stretched or biaxially stretched according to the direction of stretching in the manufacture. It is punched on a extruded polymer sheet (mostly polypropylene or high density polyethylene) and then subjected to oriented stretching under heating. The unidirectionally stretched grid is stretched only along the length of the sheet; the biaxially stretched grid is formed by continuing to stretch the unidirectionally stretched grid in a direction perpendicular to its length.
Since the polymer of the plastic geogrid is realigned and oriented along with the heating extension process, the bonding force between the molecular chains is strengthened, and the strength is improved. Its elongation is only 10% to 15% of the original board. If an anti-aging material such as carbon black is added to the geogrid, it can have good durability such as acid resistance, alkali resistance, corrosion resistance and aging resistance.
The mine grille is a kind of "double-resistance" plastic net with a plastic structure of coal mine underground, which is made of polypropylene as the main raw material and treated by flame retardant and antistatic technology. The product is easy to construct, low cost, safe and beautiful