Drug – bio-affecting and body treating compositions – Preparations characterized by special physical form – Biocides; animal or insect repellents or attractants
Reexamination Certificate
1999-06-04
2003-03-18
Levy, Neil S. (Department: 1616)
Drug, bio-affecting and body treating compositions
Preparations characterized by special physical form
Biocides; animal or insect repellents or attractants
C424S411000, C514S531000
Reexamination Certificate
active
06534079
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates generally to insect control and more particularly to passive insect control articles that are effective in killing or repelling mosquitoes.
For certain applications, it is important to be able to control flying insects for six to ten hour or even longer periods within defined areas such as the enclosed space of a bedroom. Such a duration of insect control is desirable, for example, to protect a sleeper occupying an unscreened room from mosquitoes for a single night. It is also useful to be able to deliver an insect controlling amount of active ingredient nightly for multiple nights in succession. Successful flying insect control is also useful in other living spaces, including screened areas that for any reason are still subject to invasion by flying insects, as well as outdoor areas such as a patio, or the like.
Traditionally, articles or devices that dispense insecticide vapors to control insects in such settings require heating or burning a liquid or solid substrate to evaporate the active ingredients. For example, conventional citronella candles have long been used for such purposes. Burning insect coils are also commonly used to achieve a night's insect control or to control mosquitoes or other insects in outdoor areas. The product sold by S. C. Johnson & Son, Inc. of Racine, Wis. under the trademark “45 Nights” is an example of a type of product known in the art for delivering insect control over repeated periods of use, such as a nightly use in an unscreened bedroom. The “45 Nights” product is an example of conventional heated, liquid evaporation insect control products.
The products referred to above all can be effective, within certain limits. However, products that require a heat source also require a safe burning site, e.g. in the case of insect coils, or may require a source of house electrical current for typical heated evaporation products. Products exist that are designed to avoid some of these difficulties by employing passive evaporation of insect control active ingredients without the application of heat. However, they have problems and limitations when compared to insect control strategies employing products requiring the application of heat.
For example, Regan, U.S. Pat. No. 339,810 uses a tobacco preparation as a repellent that is first soaked into cloth or paper and then dried. The repellent active ingredient is reported to evaporate from the substrate to repel insects. More recent technology such as that disclosed in Landsman et al, U.S. Pat. No. 3,295,246 has included the use of pyrethrum or pyrethroid materials as passively evaporated insect control active ingredients. Ensing, U.S. Pat. No. 4,178,384 employs pyrethroids as repellents applied to the locus to be protected.
Whitcomb, U.S. Pat. No. 4,130,450 describes an insecticide-impregnated, open, low-density web that provides an expanded surface that may be loaded with contact insecticides, including pyrethrum and synthetically prepared insecticides. Whitcomb prefers the use of micro-encapsulated pyrethrum to avoid pyrethrum instability when exposed to ultraviolet light and oxygen. Whitcomb mentions that the web may be hung to permit vaporization of the active ingredient to combat flies. Similarly, Chadwick et al, U.S. Pat. No. 5,229,122 utilizes a mixture of micro-encapsulated and non-micro-encapsulated active ingredients, noting that any known pesticide may be used for the purpose. Pyrethrunim or a pyrethroid equivalent are referred to as possible pesticides. The preparation is used to coat surfaces, although it is also noted that the vapor phase of the pesticides may be valuable.
Kauth et al, U.S. Pat. No. 4,796,381, is an example of the use of paper or textile strips impregnated with insecticide that is allowed to evaporate to control insect pests. The Kauth et al materials utilize pyrethroids and, in particular, vaporthrin, permethrin, and bioallethrin. However, the devices of Kauth et al are designed to be hung in closets or placed in drawers, suggesting that they are understood to be inadequate to protect larger, more open spaces. Nothing in Kauth et al suggests any ability of their paper or textile strips to control insects in relatively large air spaces.
Samson et al, U.S. Pat. Nos. 5,198,287 and 5,252,387 disclose a fabric for use in a tent, the fabric including a coating that contains evaporable insecticides, and in particular, permethrin. Again, a confined space is being protected.
Aki et al, U.S. Pat. No. 4,966,796, utilizes a pyrethroid insecticide on kraft paper, with additional layers of untreated kraft paper added to create a material useful for making an insect-resistive packaging material or bag.
Landsman et al U.S. Pat. No. 3,295,246 teaches the use of an insecticide-soaked and then dried paper that is coated with resin to slow evaporation of the active ingredient. The resin coating is deemed important to make an insecticide product that will be effective over a long period of time. Example formulations cited in Landsman et al include pyrethrins as active ingredients. The Landsman et al product is not intended to protect large volumes of air and is also an example of the difficulty known in the art of achieving protection over an extended period of time because of the evaporative rate of active ingredients.
Ronning et al, U.S. Pat. No. 4,765,982 is an example of the use of micro encapsulated active ingredients to achieve a sustained release insect control effect. Pyrethroids, either synthetic or “natural,” are cited as useful. The Ronning et al insecticidal device may be hung in the open to achieve a repellent effect in a restricted locale to drive insects from a nest or the like.
Yano et al, U.S. Pat. No. 5,091,183 and Matthewson, U.S. Pat. Nos. 4,940,729 and 5,290,774 cite specific insecticidal compounds for volatilization. Yano et al specifically discusses the use of impregnated papers for heatless evaporation of an insecticidal compound.
Clarke, U.S. Pat. No. 2,720,013, describes the use of a fabric material into which active ingredients are pressed or fused. Pyrethrum is cited as useful not by itself but as at least one element in a mixture of insecticides. The Clarke fabric material is designed to be adhered to the blades of an electric fan so that the insecticide will be directed into the area ventilated by the fan.
Emmrich et al WO96/32843 describes an insect control article to control flying insects comprising a substrate that is impregnated with an active insect control ingredient available for passive evaporation, wherein the active insect control ingredient is selected from transfluthrin, prallethrin, vapothrin, tefluthrin, esbiothrin, dichlovos (DDVP), and combinations thereof. Emmrich et al teaches that the insect control article must then be placed in an environment with significant air currents in such a manner that the substrate of the insect control article is exposed to the air currents, and the active insect control ingredient impregnated within the substrate is allowed to evaporate passively into the air. These air currents are referred to as “significant” since they are caused by either augmenting air movement via a fan, blower, etc. or the air movement is non-augmented but has a relatively strong natural air current such as that occurring when wind blows through an open window or door. Emmrich et al's insect control article does not require any external heat be applied to the article to vaporize the active ingredient although heat will, of course, aid in the rate of evaporation of the active from the substrate.
Another device not requiring heat but requiring a relatively strong augmented air current is taught by Ito in EP0775441. This device includes a carrier supporting a substrate containing a pesticide that is hard to vaporize at normal temperatures, and a blower for developing an air current across the substrate.
As seen from the above prior art, although passive evaporation of insecticides is known in the art, the nature of those materials has been such that the attention of the art gen
Levy Neil S.
S. C. Johnson & Son Inc.
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