WATER-REPELLANT INSECTICIDE FOR TENT FABRIC

Abstract: A silicone water-repellant containing the insecticide permethrin to be used on exterior fabrics made of synthetic, natural, or blends of these fibers. This product may also be used in conjunction with a mildewcide containing 2-n-octyl-4-isothiazolin-3-one and ultra fine zinc oxide. This treatment will retain its properties for at least 60 % of the life of a typical light-weight hiking tent.

Description: WATER- REPELLANT INSECTICIDE FOR TENT FABRIC SPECIFICATION This invention relates to the finishing of fabric and more specifically to the finishing of fabric in a manner to provide the fabric with effective water-repellant and insecticidal properties. It is known to treat fabrics with protective coatings of water repellants, flame retardant chemicals, mildewcide, and insecticides or combinations thereof. The applications of these products have undergone extensive use in exterior applications such as tent fabrics, awnigs, clothing, etc. U.S. Pat. Nos. 4,833,006 and 5,198,287 and 5,252,387. A synthetic pyrethroid permethrin is known for its repellant as well as knockdown and kill activity. Permethrin effectively controls a variety of pests, such as ticks, cockroaches, houseflies, mosquitoes, and other insects/arthropods. Permethrin has had very limited use in weathered applications due to its decomposition into a nonactive, non-insecticidal product in the presence of oxygen and ultraviolet light. manufactured by McLaughlin Gormley King Company contains permethrin combined with other pyrethroids or natural pyrethrins and synergists. This combination provides fast knockdown and sure kill. All products used in this insecticide are of low hazard to man and domestic animals, and are virtually odorless and pleasant to use. Various attempts have been made to stabilize the permethrin in the presence of degrading elements by using encapsulation methods or various coating techniques. U.S. Pat. No. 4,056,610 (11/1997) to Barber, Jr. et al. discloses a microcapsule insecticide composition with a polyurea shell having U.V. absorbing compounds, in which a pyrethroid permeates a porous shell wall and maintains an effective level of the pyrethroid upon the outer surface of the shell wall to control insects up to four days. Control is achieved by killing insects which contact the pyrethroid released through the capsule wall. For this purpose the capsules are spread out in various ways and are incorporated into sheet materials such as tapes. U.S.Pat. No. 4,765,982 (8/1988) to Ronning and Gregg discloses an insect control device comprising a plurality of rough- surfaced cellulosic fibers, made from a graft copolymer cellulose and an etylenically unsaturated material copolymerizable with cellulose. Wherein a liquid insecticide composition microencapsulated in a capsule, whose shell is permeable to the liquid insecticide is self-adhered to the surface of the fibers. The preferred microencapsulated insect control agents for use in Running's invention are those disclosed in U.S. Pat. No. 4,056,610 to Barber. Ronning' s insecticide treated, rough surfaced cellulosic fibers are formed into webs, tapes, sheets, pads, and various other relatively flat shapes to maximize the surface area of the device. These devices are made suitable for use in particular locations, such as a circular sheet for the top of a silo or a ribbon-like tape for placement along the base of a building or door. Ronning teaches that smooth-surfaced synthetic fiber-forming materials such as polyester and nylon do not act as good sites for adhesion of microencapsulated insect control agents. Running's rough-surfaced cellulosic fibers treated with an insecticide are not suitable for a tent fabric. The texture of the rough surfaced fibers is not satisfactory and they are neither water repellant or flame retardant. U.S. Pat No. 4,833,006 (5/1989) to Mc. Kinney discloses a flame resistant and water-repellant coating for fabric that contains a polyfunctional isocyanate as an adhesion promoter and binder to adhere the coating to the substrate in a flake proof manner. For this purpose, the coating compositions are preferably applied in a liquid state to the fabric and then processed at a temperature of 190°C (375°F) to fuse the coating composition to the fabric substrate U.S. Pat No. 5, 198,287 (3/1993) to Samson discloses a tent fabric which is coated in a sandwich structure. The fabric is coated on the outside with a water-repellant flame resistant coating, and the inside is coated with a different water-repellant flame resistant coating in which permethrin is incorporated at a concentration of 2.58 g/m 2 active. It is preferred that the outside coating be the described and claimed coating in U.S. Pat. No. 4,833,006 U.S. Pat No. 5,252,387 (10/1993) to Samson is an improvement to U.S.Pat. No. 5, 198,287 by using external barriers to prevent migration of the permethrin to the outside surface. These barriers include polymeric coatings, films, foils, fabrics, and surface treatments which are resistant to plasticizer migration. Samson's sandwich type coatings mentioned in U.S. Pat No. 5, 198,287 and U.S. Pat No. 5,252,387 are unsuitable for small nylon type hiking tents. In small hiking tents, people may be more frequently in contact with the tent fabric then in large tents where people can roam freely in an upright position. Because of this, the concentrations of permethrin should be closer to 1.25 g/m 2 , which is the accepted limit by the environmental Protection Agency (E.P. A) for use on commercially treated clothing. On light-weight hiking tents this coating will affect the feel and the breathability of the fabric, thus the fabric will appear suffer and will not permit moisture to permeate through the fabric to the outside of the tent. Because of the confined space within the tent, in cool weather condensation will form on the inner walls and may wet other items, for example sleeping bags, which touch the outer wall. U.S. Pat No. 5,503,918 (4/1996) to Samson combines permethrin with polyvinylacetate and U.S. Pat No. 5,089,298 (2/1992) to McNally combines permethrin with amylopectine, both of these treatments require a two step process in order to treat clothing such as battle dress uniforms (BDU). Neither of these processes is suitable for lightweight hiking tents since neither provides; a one-step application or water-repellancy. Ensuing on the issuance of the above mentioned patents, research has continued for effective use of permethrin in repelling mosquitoes and other insects, which may carry diseases. In the Past According to the Navy medical guide of 1984, the US Army suffered over 50,000 casualties due to malaria during the Vietnam conflict. (US Pat 5,503,918) Nowadays, because backpacking is becoming even more popular in areas where malaria is present, a search for a safe, efficient, inexpensive easy to apply water-repellant insecticide for use by individuals on small lightweight hiking tents is needed. It is the primary purpose of this invention to treat light-weight hiking tent fabric homogeneously in a one-step application, with a water-repellant and insecticide finish, that will not affect the fabric properties, and will have a duration of at least 60% of the fabric life. This invention provides a safe, efficient, inexpensive, easy to apply water-repellant insecticide for use by individuals on small lightweight hiking tents or other substrates that may require these features. Figure 1. is a perspective view of the tent Figure 2. is a sectional view taken substantially along the line A- A in figure 1. Figure 3. is a chart illustrating the durability of the product by demonstrating the percentage of mosquitoes dead or unable to fly with respect to the bright-sunshine hours of exposure and the fabric life/strength remaining. The fabric or substrate suitable for this invention can be any light weight fabric suitable for the manufacture of tents or structures of limited size. Applicants treat the light-weight hiking tent fabric or substrate with a low concentration of the insecticide EVERCIDE*Perrnethrin combined in solution with an air-drying, air-curing silicone fabric finish which serves as a water-repellant. This solution impregnates the fabric in a homogeneous manner, and provides water-repellancy and insecticidal properties without affecting the breathability or the feel of the fabric. This treatment will cure at room temperature and can be applied using a hand pumpspray, aerosol or paintbrush to the tent, or during normal commercial finish operations on the manufactured fabrics. The following composition is exemplary of the solution that can be used in practice. EXAMPLE 1 Water-repellant with insecticide for treating light-weight tent fabric. COMPONENT PERCENTAGE FUNCTION Polysiloxane in solvent 7.00 Water-repellant (Dow Corning C2-0563 Repellant) Permethrin 0.63 Insecticide (Evercide 80% cone.) Odorless Mineral Spirits 92.37 Solvent 100.00 % Ultra violet radiation along with Oxygen (O 2) are the major components associated with weathering degradation. A water-repellant coating, must repel water, it therefore helps prevent oxygen in moisture to come in contact with and diffuse into fibers or coating, thus reducing the rate of degradation. If this coating also has natural U.V. absorbing properties, which can further be enhanced by additives, it may be possible to reduce the degradation rate of the fabric or coated products. The application method, water-repellant coating durability, and U.V. properties of the water-repellant are also a concern. The silicone finish is very stable in the presence of U.V. radiation and in addition to serving as a water-repellant, the silicone finish acts as a plasticizer by coating the permethrin and creating a permeable shell around the permethrin. The silicone finish prevents the permethrin from degrading rapidly while providing a sustained release of the insecticide to the fabric. The water-repellant insecticide solution will be applied to the outside of the tent illustrated in figure 1 The solution can be applied to a tent using a hand pumpspray, aerosol or paintbrush Application of the solution would be hazardous inside the tent due to the restricted space and wall inclination Unfinished tent fabric/substrate can be commercially treated duπng normal industrial finish operations The solution should be applied in a fashion that completely saturates the fabπc as illustrated in figure 2 Such a homogeneous application will deposit approximately 0 25 g/m 2 of permethrin within a light-weight tent fabric This amount corresponds to 10 3 times less permethrin then applied to tents treated by Samson U S Pat No 5, 198,287 and 5 times less then accepted level allowed on clothing by the E P A The effectiveness of the permethrin as an insecticide has been field tested for a duration of 163 1 bright sunshine hours in the months of July and August Measurement of bright sunshine hours or U V -B radiation provide a better method for measuπng degradation caused by weathering exposure than months or days of exposure, because they do not take into account the shorter days of winter, and rainy days when the rate of degradation is reduced The water-repellant insecticide was evaluated using mosquitoes to determine i ) That the natural behaviour of the mosquitoes to land on the walls of the tent would not be influenced by the insecticide repellant properties of the permethrin ii ) The number of mosquitoes dead or unable to fly (knockdown, KD) inside the tent after an exposure of three hours iii) The duration of insecticide treatment when exposed to weathering In the case of i) mentioned above, if the permethrin repelled the mosquitoes, the mosquitoes would try and land on non-treated material such as clothing articles or people inside the tent, thus increasing the chances of biting Two dark brown light-weight hiking tents with a total surface area of 4 81 m 2 ' were erected in an open field without shade during the months of July and August to obtain the maximum effect of elevated temperatures and U V radiation, both of which increase the rate of degradation Because the sun rises in the east and sets in the west, (northern hemisphere) the tents were oriented with the door facing due south so as to maximize the surface area of fabric exposed to solar radiation. A non-coated light-weight hiking tent fabric was also exposed due south, to determine the life time of the fabric. Weekly bioassays were conducted with mosquitoes. Each week mosquitoes were released inside the tent and left for a period of three hours, during which their behaviour was studied, as well as the time until the first KD occurred. We found that the treated fabric showed no insecticide repellant effect but excellent insecticide properties and that the natural behaviour of the mosquitoes remained unaltered. Once released inside the tent, the mosquitoes immediately flew and held to the roof and walls of the tent and remained there without the need to move around. After a period of about fifty minutes the smaller mosquitoes began to lose grip, and eventually fall to the floor, while the larger ones began to show signs of intoxication. After the exposure of three hours the mosquitoes dead or alive were counted. The untreated tent showed no dead mosquitoes within the three hour time frame. After the tent had been exposed for 161.3 hours, 243 mosquitoes were let free inside the tent, of which 95% died in the first three hours. Figure 3. is a chart illustrating the durability of the product by the percentage of mosquitoes dead or unable to fly with respect to the bright-sunshine hours of exposure and the fabric life/ strength remaining. It was noticed that after 163.1 hours of bright sunshine hours of exposure the water-repellancy had diminished slightly, it is therefore suggested that at this point or later, because of the safety and simplicity of the application, that the tent be retreated to maximize the efficiency of both the water-repellant and insecticide properties. Protection by the water-repellant insecticide coating may be longer if the tent is exposed in; an intermittent fashion, in the shade, or in cooler times of the year when temperature and UN. radiation aren't as high. The following composition is exemplary of the solution that can be used in practice to reduce mildew formation, on tent/substrate that are exposed to high humidity environments. EXAMPLE 2 Water-repellant with insecticide and mildewcide for treating light-weight tent fabric. COMPONENT PERCENTAGE FUNCTION 1. 2-n-octyl-4-isothiazolin-3 -one 4.0 Mildewcide (Rohm and Haas, Skane M-8) 2. Butyl Cellosolve .05 Carrier Solvent 3. Polysiloxane in solvent 7.00 Water-repellant (Dow Corning C2-0563 Repellant) 4. Permethrin 0.63 Insecticide (Evercide 80% cone.) 5. Odorless Mineral Spirits 87.42 Solvent 6. Zinc Oxide (Ultra fine) 0.9 Mildewcide/U.V. blocking 100.00 % For best efficiency, the above formulation should be mixed in the given order. This solution can be used in the same manner as listed in the previous example. Fabric/substrate treated with this solution offers good mildewcide properties and may prolong fabric/substrate life due to the natural U.V. absorbing properties of Skane M-8 and zinc-oxide mildewcide products. The fabric was exposed to weathering in a damp environment oriented vertically and facing due north to maximize the growth of mildew on the surface. After three months of exposure, the control non-treated fabric was covered with mildew, while the treated fabric showed little or no signs of mildew. Although specific terms have been employed in describing the invention, they are used in a descriptive and generic sense only and not for purposes of limitation. The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows: 1. A fabric or substrate suitable for the making of a light-weight hiking tent or structure of limited size, treated with a solution composed of, a water-repellant and an insecticide which is resistant to degradation by UN. and oxygen. The improvement comprises in treating a lightweight hiking tent fabric homogeneously in a one step application, with a water-repellant and insecticide finish, that will not affect the fabric properties, appearance or feel, and will have a duration of at least 163.1 bright sunshine hours. Whereby this invention provides a safe, efficient, inexpensive easy to apply water-repellant insecticide for use by individuals in domestic application or by companies in industrial application, on small lightweight hiking tents or other substrates that may require these properties. 2. A treated fabric according to claim 1. wherein the water-repellant is an air-drying, air-curing silicone fabric finish. 3. A treated fabric according to claim 1. wherein the insecticide is permethrin or permethrin and synergists and/or other pyrethroids. 4. A treated fabric according to claim 1. wherein the insecticide is EVERCIDE*Permethrin 5. A treated fabric according to claim 1. to which may be added the mildewcide, 2-n-octyl-4- isothiazolin-3-one.

Claims: AMENDED CLAIMS [received by the International Bureau on 25 February 1998 (25.02.98) ; original claims 1 and 2 amended ; remaining claims unchanged ( 1 page)] 220 The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows: 1. A fabric or substrate suitable for the making of a light-weight hiking tent or structure of limited size, treated with a solution composed of, a water-repellaήt and an insecticide which is 225 resistant to degradation by UN. and oxygen. The improvement comprises in treating a lightweight hiking tent fabric homogeneously in a one step application, with a water-repellant and insecticide finish, that will air-cure at room temperature, will not repel blood sucking vermin (e.g. mosquitoes), will not affect the fabric properties, appearance or feel, and will have a duration of at least 163.1 bright sunshine hours. Whereby this invention provides a safe, 230 efficient, inexpensive easy to apply water-repellant insecticide for use by individuals in domestic application or by companies in industrial application, on small lightweight hiking tents or other substrates that may require these properties. 2. A treated fabric according to claim 1. wherein the water-repellant is a non-aqueous air-drying, 235 air-curing at room temperature silicone fabric finish. 3. A treated fabric according to claim 1. wherein the insecticide is permethrin or permethrin and synergists and/or other pyrethroids. 240 4. A treated fabric according to claim 1. wherein the insecticide is EVERCIDE*Permethrin 5. A treated fabric according to claim 1. to which may be added the mildewcide, 2-n-octyl-4- isothiazolin-3-one.

Inventors: SENECAL RENE E, SENECAL, RENE, E.
Applicants: SENECAL RENE E, SENECAL, RENE, E.
Application year: 1997
Main classification: D06M15
IPC codes: A01N53, D06M11, D06M13, D06M15, D06M16, D06N3