IL48345A - Pesticidal preparation having a depot gas action - Google Patents

Abstract

A gas-releasing depot preparation is described which can be used as a pesticide. This preparation is composed of a combination of dimethyl 2,2-dichlorovinyl thiophosphate as agent which acts autonomously by generating a gas phase, and solid carriers. Carriers which can be used are thermoplastics, duromers, elastomers or else natural substances, such as, for example, cellulose, but also mixtures of these. The preparation described is preferably suitable for controlling flies. [GB1475273A]

Description

11 n ryo >ya D»P*TO - ana · τ_οη Pesticidal preparation hvin a depot gas action BAYER AKSIEW(iI3S-3LIiSCHAFav C. 45850 Type V The presen invention relates to new preparations, having a depot gas action, based on dimethyl-2 , 2-dichloro-vinyl thiophosphate as a gassing agent which acts automatically via the gas phase, and on solid carriers..

The use of dimethyl-2, 2-dichlorovinyl phosphate (DDVP) in formulations which automatically act as gassing agents, in combating pests, has been known for a long time. ■ Very diverse materials have been proposed as carriers for the above-mentioned active compound: macromolecular thermoplastic, thermosetting and elastomeric plastics or natural materials, such as wood, cardboard, asbestos, lime, gypsum, beeswax and montan wax. Further examples of suitable carriers are natural and synthetic rubber, polyolefins such as polyethylene, polypropylene and copolymers of ethylene and propylene, polyacrylates and copolyacrylates of methyl aerylate, ethyl aerylate and methyl metacrylate, polyvinyl compounds such as polystyrene, polyvinyltoluene and polyvinyl acetate, polyvinyl halides and polyvinylidene halides such as polyvinyl chloride , polyvinyl fluoride and polyvinylidene chloride , polyvinyl acetals such as polyvinyl butyral, linear and branched polyesters and polyethers, and cellulose plastics such as cellulose acetate, cellulose propionate, cellulose butyrate and cellulose nitrate. Examples of further suitable carriers are unsaturated polyesters, epoxides, polyurethanes, phenol-formaldehyde, urea-formaldehyde and melamine-formalde-hyde resins.

The polymers and copolymers of vinyl chloride (see DT-AS (German Published Specification) 1,230,259) as well as unsaturated ol ester s ste s see D - ft Specification) 2,231,099) have been described as particularly preferred carriers, as have also polymeric acrylates and polymeric vinyl compounds such as polystyrene.

In addition to the active compound, the formulations frequently also contain auxiliaries such as plas t i cisers , stabilisers, vaporisation regulators and fillers, depending ■ on the nature of the carrier. Examples of possible plasticisers are dioctyl phthalate, alkanesulphonic acid aryl esters, trioctyl phosphate, triphenyl phosphate, dibutyl adipate, chlorinated paraffin, diisononyl phthalate, di-2- ethylhexyl adipate, di-2-ethylhexyl phthalate and di-2-ethyl- hexyl sebacate. Examples of suitable stabilisers are phenols, amines or. lower nitrogen-containing heterocyclic compounds, as well as azo and hydrazo compounds, acid anhydrides, epoxides and elementary sulphur (DT-OS (German Published Specification) 2,145,318), and also compounds which are usually employed for stabilising macromolecular substances, such as, for example, organic cadmium compounds and lead compounds as heat stabilisers for polyvinyl chloride.

Examples of suitable vaporisation regulators are palmitic acid ethyl ester, myristic acid isopropyl ester, di-n-butyl phthalate, 2-chloronaphthale e, camphor, benzoic acid, biphenyl, isobutyl benzoate and others, such as are described, for example, in East German Patent Specification 91 ,898 and also in DT-OS's (German Published Specifications) 1 ,954,501, 2,02-6,119 and 2,028,226.

Fillers may be, for example, fibres of glass, sisal, hemp, nettle, coir and flax, as well as titanium dioxide, iron oxides, kaolin, quartz and other inert materials. as mouldings such as slabs, sheets, tapes, bars, spheres, foams, strips, films, tablets or granules. If, in the course of use, such a moulding is, for example, brought into the living room or bedroom of a house, or placed, in the form of a neckband, round the neck of a domestic animal, the DDVP contained in the preparation is gradually released into the surrounding air, as a result of the vapour pressure of the DDVP or with the aid of heat sources, for energ « i'and thus ^automaticall -kills,;:,via the gas phase; •the pests present in the room and on domestic animals (see ^ - DT-AS (German Published Specification) 1,230,259; British Patent Specification 1,015,933; South African Patent Specification 62/37TV DT-AS: '(German Published Specification) ' 1,694,240; DT-OS's (German Published Specifications) 1,941,046 and 2,231,099; and DT-AS (German Published Specification) 1,802,684).

The mouldings can either be employed for use directly or be surrounded by casings (quivers), which can be opened or closed completely or partially in order thereby periodically to interrupt the release of the DDVP or to regulate the amount of active compound released.

Now the problem of using DDVP in these automatic gassing mouldings" is that the release of the active compound must be so controlled that sufficient active compound is released into the air of the room to kill the pests reliably whilst , the humans and domestic animals present in the room are not harmed. .Active compounds having a lower toxicity to mammals than has DDVP would therefore represent a great technical advance for this end use. However , 'hitherto no other compound - With regard to the thiophosphates , DT-AS 1,230,259 discloses that they are less compatible with macromolecular substances than are the phosphoric acid esters in question.

South African Patent Specification 62/371 describes, in addition to DDVP, combinations with a large number of other phosphoric acid esters and the corresponding thiophosphates .. British Patent Specification No. 1,359,136 also refers, among a large rumber/ of possible active compounds, to DDVP and 'its corresponding thio (thiono) analogues", although that Specification exemplifies only the use of DDVP. The same applies to Israel Patent Specifications Nos . 16698 and 19375. All these publications imply that DDVP is the preferred compound of this type and none of them included any hint that the substitution of that compound with a thio analogue thereof would have any advantages. It is also noteworthy that the preparations known from said British Patent 1,359,136 consist of a carrier enclosed in a coating layer through which the active substances can diffuse, whereas the preparation of the present invention do not comprise such a. coating.

Furthermore, it is generally known that thiophosphoric acid esters have a lower insecticidal power than the corresponding phosphates. The poorer insecticidal action of dimethyl-2,2-dichlorovinyl thiophosphate , (hereafter referred to for brevity as thio-DDVP) compared to DDVP is shown by the following comparison experiment: Aerosol test Test animals: Musca domestlca Solvent: Acetone To produce a suitable preparation of active compound, the active compound was mixed, at a range of concentrations, with the stated solvent.

A wire cage which contained about 25 test animals was suspended in the centre of a gas-tight glass chamber of size 1 m^. After the chamber had been closed again, 2 ml of the preparation- chamber. The condition of the test animals was constantly checked from outside, through the glass walls, and the time required for a knock-down effect on 50$ of the animals was determined* The active compounds, amounts used and time after which 50# of the animals were lying on their backs (LT^Q) can be Been from the table which follows: T a l e 1 Aerosol test Thio-DDVP 19Ί5 11 '40" It is therefore not surprising that the above-mentioned publications do not contain an example of the use of thio-DDVP.

It has now been found that, surprisingly, thio-DDVP can advantageously be employe_d in place, of DDVP. as an active ... . compound in preparations having a depot gas action if it is employed, in combination with solid carriers, as a gassing agent, acting automatically via the gas phase, for combating pests*.

As such preparations,' t- is possible "to' use": combinations"' — which consist of thio-DDVP and macromolecular thermoplastic, elastomeric or thermosetting plastics or natural materials such as wood, cardboard, asbestos, lime, gypsum, felt, beeswax or mohtan wax as carriers.

In addition, to "the ■ active- compoundy "the preparations' " in question can, depending on the nature of the carrier, also contain the above-mentioned auxiliaries such as, for example, plasticisers, stabilisers, vaporisation regulators, vaporisation inhibitors or vaporisation promoters, and fillers.

The preparations may be used in the form of shaped articles such as slabs, Bheets, tapes, bars, spheres, foams, strips, films, tablets, neckbands or granules. They can be surrounded b casings which permit a controllable full or reduced release of active compound. A factor which proves particularly advantageous in the use, according to the invention, of thio-DDVP. is that compared to DDVP the active compound, and its degradation products, decomposition products and possible by-products have a lower toxicity to warm-blooded animals, as can- be seen from the table which follows: T a b l e 2 LDcn male rats Acute oral toxicity DDVP 62 mg/kg • Thio-DDVP 773 mg/kg LCcn male rats Acute inhala- , tion toxicity DDVP 340 mg/nr (4 hours · , exposure)' . Thio-DDVP >477 mg/nr * ♦This concentration, which is" the maximum possible in the experiment, was tolerated without symptoms by the animals.

The preparations according to the invention, based o thio-DDVP as an automatically acting gassing agent, and solid carriers, can be used to combat a great diversity of species of pests. The thio-DDVP to be used as the active compound according to the invention is known from the literature and can be prepared, for example, in accordance with the process described in DT-OS (German Published Specification) 2,238,921, The following examples explain the invention in more For Examples 1 and 2, the carrier used was in each case a mixture of 440 parts of an unsaturated polyester (prepared by polycondensation of 205.8 parts of maleic anhydride, 72.5.2 parts of phthalic anhydride, 546.4 parts of 1 ,2-propane-diol and 0.265 parts of hydroquinone, and having an acid number •of 42) and 240 parts of styrene (polyester mixture 1).

, For Examples 3 and 4, the carrier used was in each case a mixture of 730 parts of an unsaturated polyester (prepared by polycondensation of 262.8 parts of maleic anhydride, 926.8 parts of phthalic anhydride, 612 parts of 1 ,2-proparie-diol, 359. 6 parts of . dipropylene glycol and 0.21 4 parts of* hydroquinone, and having an acid number of 3.9) and 350 parts of styrene (polyester mixture 2).

Example 1 A homogeneous premix was prepared from 680 parts of polyester mixture 1, 390 parts of thio-DDVP, 230 parts of alkanesulphonic acid aryl ester and 27 parts of maleic anhydride. After adding 41 parts of a 10 strength solution of dimethylaniline in toluene, a cast sheet having a glass fibre content of 26 was produced by heating the mixture for about 30 minutes to 80-100°C in a closed mould in which a glass fibre mat (600 g/m ) had been laid. The sheet was subsequently cut into shaped pieces of size 8 x 25 cm. The active compound content was 20 g.

Example 1a ' - . (Comparison example) Shaped pieces of size 8 x 25 cm and havin an active compound content of 20 g were produced in the same manner as described in Example 1 , but using DDVP as the active compound. polyester mixture 1 and 450 parts of thio-DDVP. After adding 36 parts of benzoyl peroxide in phthalate plasticiser ( 50 strength) , a cast sheet having an asbestos content of 3.5 per cent by weight was produced by heating for about 30 minutes to 80-100°C in a closed mould, into which granular asbestos particles had been introduced. The sheet was subsequently cut into shaped pieces of size 8 x 25 cm, having an active compound content of 38%.

. Example 3 A homogeneous premix was prepared from 665 parts of polyester mixture 2. and 475 parts of thio-DDVP. After adding 38 parts of benzoyl peroxide in phthalate plasticiser ( 0% strength),, a cast sheet with a fabric content of 26 per cen by weight was produced by heating for about 30 minutes, to 80-100°C in a closed mould, into which a fabric of poly-acrylonitrile fibres (280 g/m ) had been laid. The sheet was subsequently cut into shaped pieces of size 8 x 25 cm, having an active compound content of 24 g each.

Example 3a (Comparison example) A homogeneous premix, and shaped pieces of the same sizes and of the same active compound content, were prepared in the same manner as in Example 3» but using DDVP as. the active compound.

, Example 4 A homogeneous premix was prepared from 438 parts of polyester mixture 2 and 299 parts of thio-DDVP. After adding 26 parts of benzoyl peroxide in phthalate plasticiser (50% strength), a cast sheet with a weight content of 26 per cent 80-100°C in a closed mould, into which a jute fabric (1,150 g/ m ) had been laid. The sheet was subsequently cut into shaped pieces of size 8 x 25 cm, having an active compound content of 25 g each.

Example 4a (Comparison example) A homogeneous premix, and shaped pieces of the same sizes and of the same active compound content, were prepared in the same manner as in Example 4, but using DDVP as the active compound.

Example 5 Shaped pieces of size 8 x 25 cm were cut from 3 mm thick cardboard and impregnated with thio-DDVP. The active compound content in the cardboard was 30 g.

The pesticidal activity of the present formulations is illustrated in the following biotest Examples.

Example A One shaped piece produced according to Example 1 and one shaped piece produced according to Example 1a were each pushed into a casing of fine wire mesh and suspended from the •z ceiling in the centre of identical rooms of 50 m cubic capacity. Four weeks later, 200 flies of the species usca domestica were released in the rooms. In the room in which the shaped piece according to Example 1 was suspended, the flies dropped after 2 hours. In the room in which the shaped piece according to Example 1a was suspended, it required 3 hours for 100$ of the flies to lie on their backs.

Example B One shaped piece produced . according to Example 3 and one sha ed iece roduced ac ordin to Exam le a were a h in the centre of identical rooms of 40 m cubic capacity.

Immediately thereafter (0), and after 4, 8 and 12 weeks, 200 flies of the species Musea domestica were in each case exposed, in the rooms. The flies did not come into direct contact with the shaped pieces. In each case, the percentage of animals which had fallen on their backs was determined 1 hour after exposing the flies. The results obtained can be seen from the table which follows: . a b l e 3 Age of the shaped percentage of animals lying on pieces, in weeks their backs after one hour DDVP . Thio-DDVP 0 80 100 4 . 70 95 8 , . ' ■ 60 90 12 20 ' 50 Example C One shaped piece produced according to Example 4 and one shaped piece produced according to Example 4a were each pushed into, an open-pore quiyer and suspended open in a room. After 2 weeks, the shaped piece according to Example 4 was first brought into a room of 43 m cubic capacity and 300 flie of the species usca domestica were released. The time after which 100 of the flies had fallen on their backs was determined. Thereafter the room was thoroughly aired and the same experiment was carried out with. the shaped piece according to Example 4a. The results obtained are shown in the following table: T a b l e 4 Sha ed iece accordin Time ela sed before 100 of

Claims (11)

1. What we claim is: 1. A pesticidal preparation having a depot gas action,, which preparation comprises dimethyl-2 , 2-dichlorovinyl thiophosphate as a gassing agent, in admixture with a solid carrier.

2. A preparation according to claim 1, in which the carrier comprises a synthetic, macromolecular substance.

3. A preparation according to claim 2 ; in which the carrier comprises a thermoplastic material, a thermosetting resin or an elastomeric material.

4. A preparation according to claim 1, in which the carrier comprises a naturally occurring material or is derived from a naturally occurring material0

5. A preparation according to claim 4, in which the carrier comprises asbestos, lime or gypsum.

6. A preparation according to claim 4, in which the carrier comprises a cellulose- or keratin-containing material,,

7. A preparation according to claim 6, in which the carrier comprises wood, cardboard or felt.

8. ■ A preparation according to any of claims 1 to 7 in which the solid carrier comprises a mixture of materials.

9. A preparation according to any of claims 1 to 8, which also comprises one or more auxiliaries or fillers selected from plasticisers, stabilisers, vaporisation promoters or inhibitors, glass fibres, textile fibres, pigments, dyestuffs, scents and quartz.

10. A preparation according to any of claims 1 to 9 where contained in a casing which adjustably provides for full or reduced release of the gassing agent. .

11. A preparation according to claim 1, substantially as hereinbefore described in any of Examples 1 to 4. the pests or their habitat to dimeth 1-2, 2-dichlorovinyl thiophosphate emitted as a gas from a preparation according to any of claims 1 to 11 · 13· A method according to claim 12 in which the pests are insects. 14. A method according to claim 13, in which the pests are flies.