Poisons - Interfere with the keratin digesting process of the larvae. Killing the feeding larvae.- - By blocking enzymes need for digestion. -lower environmental hazard than nerve poisons. -Not effective against some pests.
- Control agents. Nerve Poisons -Affecting a broader range of insects -More rapidly biodegraded than poisons. -Less durabillity.
Dieldrin. 1- One of the original nerve poisons. Permethrin. 2-Higly toxic to mammals. 3- Banned in most countries 1- very effective against moth larvae. 2-Less effect on Anthrenus beetles. 3- combination products of permthrin and hexahydropyrimidine derivatives.
Application of insect resist finishes. Insect resist finish During spining During scouring During Dyeing
During dyeing - The best light and wet fastness properties The finish is able fully penetrate the fibres -cholrphenylid drivatives. -Exhaust well to nylon. - Leaving wool unprotected. -Permethrin-based products. - Distribute them selves more uniformly between two fibres.
During Scouring. -For carpets, blankets &upholstery. -Do not completely penetrate the fibres. - Lower temperatures & shorter time for treatment in process. - So fastness properties are not durable.
During Spinning. - Combine the finish with spinning lubricants. -Then to apply the combination to loose wool prior to spinning -Produces yarns with only superficial treatment. - Much lower fastness.
Evaluation. Microscopic methods Measure the weight loss of the treated fabrics Measure the weight of insect excrement.
Troubleshooting. 1-Exposure to light, dry cleaning and shampooing can reduce the effectiveness of finish. 2- Finish baths that are not completely depleted of insect finishes. 3-Special are must be taken to prevent release of these insect poisons to the environment.
Finishes for protection from dust mites. Dust mites Pillows,bedding and quilts. upholstery carpets Mattresses