Types of Plastic Netting
There are fundamentally two different kinds of plastic netting in terms of strand structure, diamond netting and square netting. Further, there are two different processes that result in distinct product characteristics; extruded (or cast) netting and oriented netting.
Diamond and square netting refer simply to the shape of the hole made by the strands. Diamond netting results from two strands overlaying each other, typically at a 90-degree angle but ranging from 40 degrees to 105 degrees, to create a diamond hole pattern. Diamond netting is the most common type of extruded plastic netting. Square netting results from strands being formed along the x and y plane, creating a square or rectangular hole pattern. Both types of products are produced in a wide range of configurations, ranging from fine “filtration-grade” netting that would resemble a woven product, to more course extrusion typical of plastic construction fence.
Extruded netting can be subsequently heated and stretched to produce lighter-weight materials. This process is called orientation. Essentially, the plastic is heated and stretched under conditions that optimize its tensile strength. A common application for oriented diamond netting is the produce and packaging markets, where plastic netting is used for potato bags, onion bags, turkeys and other packaging applications.
Plastic netting can also be stretched on larger tenter frames. This process is capable of producing wider goods, as wide as 17’ or more. The tentering method of orientation will always result in square (or rectangular) netting, as the material is pulled or oriented along its x and y-axis. Either square or diamond extrusion can be tentered, though diamond netting must be cut on the bias in order to be oriented on a tenter frame. There are many applications for oriented square netting, but it primarily provides reinforcement for other substrates.
All extruded plastic netting is extruded in tubular form. It is most common for the tubular netting to be slit open longitudinally during the process to create a flat roll of material. In some cases, however, the netting is kept in its tubular form. The oriented produce bags for packaging referenced earlier is one such example. Another example in the filtration industry is rigid plastic (netting) tubes for center cores or outer sleeves (cartridge filtration). Tubular structures are also produced to be flexible or stretchy, as is often seen on the outside of cartridge filters. There are other applications as well for rigid and flexible tubular plastic nets.
The range of products and markets for plastic netting are quite diverse. To see all of the products and uses, one might think many processes were used to produce such products. But, in fact, the extrusion and orientation processes are capable of producing an ever-widening array of products for the filtration industry and other markets.