Insect resist finishes

The most important market for insect resist finishes is the carpet industry. More than two-thirds of these finishes are nsed with floor coverings and wall hangings. Other significant markets include home furnishing and upholstery fabrics, blankets, uniforms, apparel and furs. 

The usual application level of insect resist finishes varies from 0.1 to 1.5 % on... 

Digestive poisons used as insect resist finishes. 

Digestive poisons were the first durable insect resist finishes to be commercialised. Early products were based on chlorinated triphenylmethanes (Fig. 16.1a) and chlorphenylids (Fig. 16.1b). Later, sulcofenurons (Fig. 16.1c) and flucofenurons (Fig. 16.Id) were introduced. These compounds could, for the most part, exhaust to wool under acidic conditions and have reasonable fastness properties. 

Insect resist finishes are most commonly applied during dyeing. The best light fastness and wet fasmess properties are obtained when the finish is able to fully penetrate the fibres. When applying insect resist finishes to wool/nylon blends, care must be taken in the choice of the particular finish used. Chlorphenylid derivatives exhaust preferentially to nylon, leaving the wool fibres unprotected, whereas permethrin-based products distribute themselves more uniformly between the two fibre types. 

A third approach to the application of insect resist finishes is to combine the finish with spinning lubricants and then to apply the combination to loose wool prior to spinning. This method of finish application produces yams with only a superficial treatment with much lower fastness than applications made during dyeing or scouring. 

Chemical cleaning of wool textiles as smaller carpets, wall hangings, upholstery fabrics, furs or uniforms can easily be combined with the application of insect resist finishes. Dip and cautious spray application is used for the protection of wool and silk textile exhibits in museums. 

The efficiency of insect resist finishes can be determined by tests that measure the weight loss of the treated fabrics and/or the weight of insect excrement after exposure to insects under controlled conditions. The direct examination of exposed fabrics by microscopic methods to observe fibre damage is also useful. The typical half round bite traces of the moth larvae are observable. Standard methods for evaluating fabrics with insect resist finishes are given in AATCC Test Method 24. Procedures for cultivating the test insects are included in this method. 

Exposure to light as well as mild washing, dry cleaning and shampooing can reduce the effectiveness of insect resist finishes significantly. The durability requirements of the final product must be carefully considered during product development. 

Finish baths that are not completely depleted of insect resist finishes must be disposed of in accordance with local, state and federal regulations. Special care... 

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