The World Health Organization (WHO) provides specific construction of the nets for safety and reliable protection against mosquito bites. In addition to the mechanical protection provided by the textile construction, mosquito nets must provide chemical protection by treating them with a contact insecticide. The most frequently used pyrethroids are applied to the nets by a standard impregnation process or by long lasting impregnation (LLI).
Warp-knitted mosquito nets are mainly produced on two-bar tricot machines, such as the TM 2 and HKS 2-M.
The machines operate in gauges E 28 or E 32 when working polyester filament yarns. If polyethylene (HDPE) monofilament yarns are used, they are worked usually in gauge E 14. The two types of yarns have different constructions and properties and also differ as to how they are used in conjunction with the insecticide. Whilst the warp-knitted polyester textile is impregnated with the chemical at the finishing stage, the agent is already present in the HDPE at the granulate stage.
Karl Mayer's machines meet stringent requirements in terms of dimensional stability and uniformity of the mesh openings, tear resistance and weight per unit area, according to a company press release. (HO)
Karl Mayer