Silicon elastomers with insecticidal effect

Drug – bio-affecting and body treating compositions – Preparations characterized by special physical form – Biocides; animal or insect repellents or attractants

Reexamination Certificate

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C424S409000, C424S486000

Reexamination Certificate

active

06183765

ABSTRACT:

The invention relates to insecticidal silicone elastomers, processes for their preparation and their use for controlling or repelling insects, in particular in interior spaces. These novel compositions are characterized in that they contain at least one type of insecticide which is incorporated in a suitable silicone elastomer.
The silicone elastomers according to the invention are characterized in that they are capable of releasing the insecticides comprised in them, with or without heating, without changing their form in the process. Thus, optimum effectiveness and duration of action is achieved while the energy input is kept low. This novel insecticidal formulation is to be employed against all flying insects, in particular mosquitos, biting flies, etc., without using a container of any form, optionally by warming the suitable insecticide-comprising silicone elastomer in a suitable heating device.
In the case where for example mosquitos are killed using an electrical heating device, a so-called tablet vaporizer, it is known that suitable materials, such as pulp or cotton cardboard, asbestos or ceramic are impregnated with pyrethroid insecticides to obtain insecticide tablets. The insecticides are volatilized by the action of a heating device generating temperatures of 120-190° C. The gel evaporator is based on a similar principle, the insecticide being incorporated in a gel formulation.
Another method for controlling for example mosquitos is the use of so-called liquid evaporators where an insecticidal liquid formulation is evaporated continuously via a wick system by warming.
A considerable disadvantage of all these prior-art evaporation principles is furthermore the fact that the user may come into contact with the active compound or the active compound formulation, for example by the liquid formulation in liquid vaporizers leaking or by small children chewing and swallowing the paper tablets for tablet vaporizers.
A further disadvantage of the prior-art vaporizer systems mentioned is the non-uniform release of active compound.
Additionally, the duration of action of tablet vaporizers is limited to a maximum of 12 hours.
The present invention relates to silicone-based insecticidal elastomers which do not have the above-described disadvantages and are, in addition, easy to use, for example incorporated as a polymer block in known aluminum pans (EP 0 321 279) or as a polymer block directly on the surface of the heater of known vaporization devices, like those used for gel vaporizers (EP 0 321 279). Thus, a continuous release rate is achieved at a low working temperature of 60 to 150° C., preferably 80-120° C.
The silicone elastomers having insecticidal action according to the invention include mixtures comprising at least one silicone elastomer and at least one type of an active pyrethroid compound.
Suitable silicone elastomers which can be prepared by crosslinking of organopolysiloxane materials using a hydroxysilylation reaction of vinyl-containing siloxanes in the presence or absence of platinum catalysts or by using alkoxysilanes in the presence or absence of tin compounds, and the preparation of such suitable silicone elastomers, are disclosed in German Offenlegungsschrift DE-A-40 14 310.
Suitable silicone elastomers based on organosilicone materials which are crosslinkable to elastomers using organic peroxide compounds, and their preparation, represent the prior art, cf. U.S. Pat. Nos. 3,261,801, 3,468,838 and 3,865,778.
Suitable silicone elastomers based on organosilicone materials which are crosslinked using at least one basic inorganic solid are disclosed in German Offenlegungsschrift DE-A-29 11 352.
Suitable silicone elastomers based on organosilicone materials crosslinked by adding polycarbodiimide polysiloxane copolymers are disclosed in European Patent Application EP-A-00 10 708.
The following are preferred as active pyrethroid compounds:
1) natural pyrethrum,
2) 3-allyl-2-methyl-cyclopent-2-en-4-on-1-yl d/l-cis/trans-chrysanthemate (allethrin, Pynamin®),
3) 3-allyl-2-methyl-cyclopent-2-en-4-on-1-yl d-cis/trans-chrysanthemate (Pynamin forte®),
4) d-3-allyl-2-methyl-cyclopent-2-en-4-on-1-yl d-trans-chrysanthemate (Exrin®),
5) 3-allyl-2-methyl-cyclopent-2-en-4-on-1-yl d-trans-chrysanthemate (Bioallethrin®),
6) N-(3,4,5,6-tetrahydrophthalimido)-methyl dl-cis/trans-chrysanthemate, (phthalthrin, Neopynamin®),
7) 5-benzyl-3-furylmethyl d-cis/trans-chrysanthemate (resmethrin, Chrysronforte®),
8) 5-(2-propargyl)-3-furylmethyl chrysanthemate (Furamethrin®),
9) 3-phenoxybenzyl 2,2-dimethyl-3-(2,2-dichlorovinyl)-cyclopropanecarboxylate (permethrin, Exmin®),
10) phenoxybenzyl d-cis/trans-chrysanthemate (phenothrin, Sumithrin®),
11) &agr;-cyanophenoxybenzylisopropyl-4-chlorophenyl acetate (fenvalerate, Sumicidin®),
12) (S)-&agr;-cyano-3-phenoxybenzyl (1R,cis)-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropanecarboxylate,
13) (R,S)-&agr;-cyano-3-phenoxybenzyl (1R,1S)-cis/trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropanecarboxylate,
14) &agr;-cyano-3-phenoxybenzyl d-cis/trans-chrysanthemate,
15) 1-ethinyl-2-methyl-2-pentenyl cis/trans-chrysanthemate,
16) 1-ethinyl-2-methyl-2-pentenyl 2,2-dimethyl-3-(2-methyl-1-propenyl)-cyclopropane-1-carboxylate,
17) 1-ethinyl-2-methyl-2-pentenyl 2,2,3,3-tetramethylcyclopropanecarboxylate,
18) 1-ethinyl-2-methyl-2-pentenyl 2,2-dimethyl-3-(2,2-dichlorovinyl) cyclopropane-1-carboxylate,
19) (1R)-3-propargyl-2-methyl-cyclopent-2-en-4-on-1-yl cis/trans-chrysanthemate (prallethrin)
20) 2,3,5,6-tetrafluorobenzyl (+)-1R-trans-2,2-dimethyl-3-(2,2-dichlorovinyl)-cyclo-propanecarboxylate (transfluthrin, Bayothrin®) or mixtures of these active compounds.
The active compounds 3-allyl-2-methyl-cyclopent-2-en-4-on-1-yl d-cis/transchryanthemate (Pynamin forte®) and 2,3,5,6-tetrafluorobenzyl (+)-1R-trans-2,2-dimethyl-3-(2,2-dichlorovinyl)-cyclopropane-carboxylate (transfluthrin) are particularly preferred.
Suitable fillers for the compounds according to the invention are for example finely divided pyrogenic or precipitated silicas having a BET surface area of 50 to 500 m
2
/g. Such fillers may be surface-modified, for example with organosilicon compounds. The modification can also be carried out during incorporation into the polymer by adding for example hexamethyldisilazane or 1,3-divinyl-1,1,3,3-tetramethyldisilazane.
Furthermore, substances such as for example diatomaceous earth, finely divided quartz meals, amorphous silicas or carbon blacks may be incorporated as fillers.
Furthermore, additives such as, for example, organic or inorganic auxiliaries may be incorporated in the mixtures according to the invention, for example as stabilizers, colorants or perfumes.
Suitable organic and inorganic auxiliaries are:
Ammonium salts and ground natural rocks such as kaolins, clays, talc, chalk, quartz, attapulgite, montmorillonte or diatomaceous earth, and ground synthetic minerals, such as finely divided silica, alumina, titania and silicates; as solid carriers for granules there are suitable:
for example crushed and fractionated natural rocks such as calcite, marble, pumice, sepiolite, dolomite, and synthetic granules of inorganic and organic meals, as well as granules of organic material, such as sawdust, coconut shells, maize cobs and tobacco stalks; as emulsifying or foam-forming agents there are suitable:
for example nonionic and anionic emulsifiers, such as polyoxyethylene fatty acid esters, polyoxyethylene fatty alcohol ethers, for example alkylaryl polyglycol ethers, alkylsulfonates, alkyl sulfates, arylsulfonates and albumen hydrolysates; as dispersants there are suitable:
for example lignin-sulfite waste liquors and methylcellulose.
Adhesives such as carboxymethylcellulose and natural and synthetic polymers in the form of powders, granules or latices, such as gum arabic, polyvinyl alcohol, polyvinyl acetate, as well as natural phospholipids, such as cephalins and lecithins, and synthetic phospholipids can be used in the insecticide-comprising silicone elastomers according to the invention. Other additives can be mineral and vegetable oils.
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