Bleaching and dyeing; fluid treatment and chemical modification – Chemical modification of textiles or fibers or products thereof
Reexamination Certificate
2000-08-23
2004-01-20
Gupta, Yogendra N. (Department: 1751)
Bleaching and dyeing; fluid treatment and chemical modification
Chemical modification of textiles or fibers or products thereof
C008S189000, C008S190000, C514S478000
Reexamination Certificate
active
06679922
ABSTRACT:
FIELD OF THE INVENTION
In general, this invention relates to methods for the protection against pesticides, and more particularly, this invention relates to processes for making articles capable of detoxifying pesticides.
BACKGROUND OF THE INVENTION
Due to the toxicity of pesticides, protection of agricultural and farm workers against exposure and contact is highly desirable. Without proper protection, dermal exposure to pesticides can lead to skin sensitization, cancer, birth defects and even death. One effective means of protection of agricultural field workers is by using protective clothing. Currently, pesticide protective clothing is made of disposable and non-permeable synthetic materials. These materials cannot be comfortably worn in all seasons due to the generation of heat stress to agricultural workers. In addition to the discomfort and impermeable properties of these materials, synthetic materials are non-biodegradable, thus, serious environmental concerns exist.
In general, the movement of pesticides on fabrics used for protective clothing can be characterized in terms of permeation and penetration (see, Easter, E. P. and Nigg, H. N.,
Review of Environmental Contamination and Toxicology
, Vol. 129, 1992, p 1-15). Permeation is the process by which a chemical moves through a material on a molecular level. Such movement includes the sorption of molecules of the chemicals into the contacted surface of the material, the diffusion of the adsorbed molecules in the material and the desorption of molecules from the inside surface of the material into the collecting medium. Penetration, on the other hand, is the flow of a liquid chemical through closures, porous material, and material imperfections on a non-molecular level. In both cases, a physical barrier can effectively prevent any movement of pesticides through the fabrics. Materials that are considered as physical barriers to chemicals are those that will not allow any measurable movement of pesticides through them. Oftentimes, these barrier materials are specifically referred to as chemically resistant materials. Being thick and heavy, these chemical resistant materials disallow permeation and respiration at the same time, hence, generating tremendous heat stress and physical discomfort to wearers.
Since the surface contact of pesticides with materials such as fabrics, occurs by both permeation and penetration mechanisms, new methods are needed to decontaminate the pesticides on the fabrics. Methods are needed that will restrict the movement and infiltration of pesticides on the surface of the textiles such as workers' clothing. The present invention fulfills these as well as other needs.
SUMMARY OF THE INVENTION
Due to the high toxicity of pesticides and the concomitant high dermal absorption suffered by farm workers, protection of agricultural and farm workers against pesticide exposure and contact is imperative. As such, the present invention provides a process for making an article, such as a textile material, capable of detoxifying a pesticide, the process comprising:
(a) immersing the article in an aqueous treating solution which comprises a catalyst, a wetting agent and a heterocyclic amine; and
(b) treating the article with a halogenated aqueous solution, thereby rendering the article capable of detoxifying a pesticide.
Surprisingly, the inventors have discovered that chemical detoxification of pesticides can be carried out on the surface of textile materials if a reactive chemical is permanently incorporated on the surface thereof. Consequently, the textile materials of the present invention provide outstanding protection as well as comfort.
The articles of the present invention include, but are not limited to, textiles such as cellulosic fabric, cellulosic yam, cellulosic fiber, cotton/polyester blends, cellulosic/synthetic blends, polymers such as synthetic polymers, wood products and the like. In a preferred aspect, the present invention provides shirt-weight cotton-containing apparel for field workers that are capable of detoxifying pesticides. The apparel that undergoes the processes of the present invention has the surprising advantage of being capable of detoxifying pesticides, thus rendering the apparel an excellent choice for farm workers. Moreover, the treated cotton fabrics are comfortable and breathable and thus, the workers' heat stress is also reduced.
In another aspect, the present invention provides a process for detoxifying a pesticide, comprising: contacting the pesticide with an article having an N-halamine attached thereto, thereby detoxifying the pesticide. As the pesticide comes in contact with fibrous materials of the articles upon permeation or penetration, chemical detoxification of the pesticides can be carried out on the surface of the treated textile materials or articles. In this aspect, a reactive chemical, such as a N-halamine, is permanently incorporated on the surface of the textile while maintaining integral textile properties. In certain aspects, the textile materials contain active functional groups such as chlorine, which have been discovered to be an excellent detoxifying agent in the decomposition of pesticides.
These and other aspects will become more readily apparent when read with the accompanied figures and the detailed description that follows.
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Database WPI, Section Ch, Week 199436, Derwent Publication Ltd., London, GB; AN 1994-291518, XP002157475 & KR 9 309 035B (Res Inst Nat Defence Sci), Sep. 22, 1993 abstract.
Ko Louise L.
Shibamoto Takayuki
Sun Gang
Gupta Yogendra N.
Kumar Preeti
The Regents of the University of California
Townsend and Townsend / and Crew LLP
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