AU648836B2 - Improved pesticidal formulation - Google Patents

Description

6 4 8 6 P/00/0011 Regulation 3.2

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

o oo *I *u oe Name of Applicant: CIBA-G Actual Inventor(s): PAUL R Address for service in Australia: Invention Title: EIGY NEW ZEALAND LIMITED ONALD KILBEY CARTER SMITH BEADLE, Qantas House, 2 Railway Parade, Camberwell, Victoria, 3124, Australia, Attorney Code SA.

IMPROVED PESTICIDAL FORMULATION s The following statement is a full description of this invention, including the best method of performing it known to me/us: -1- 1&L- This invention relates to a pesticidal formulation.

Diazinon is a known insecticide which has been used for many years to control certain insect and other pests. In some situations, it is desirable to boost the insecticidal action of diazinon by using Sone of the more highly active synthetic pyrethroids which have been more recently introduced. When applying two or more pesticides, it is always more beneficial to have one formulation containing two or more of the active ingredients. One highly effective synthetic pyrethroid is permethrin. Both diazinon and (0 permethrin are normally available as wettable powders, but when these are mixed together to form a formulation in a desired ratio, it is difficult to obtain a homogeneous mix of the two active substances and what tends to happen is a layering effect of the active ingredients. When using such a mixture, different results \S will be obtained depending upon the particular "layer" of active material utilised at any particular time.

This invention has as its object a formulation and method of producing such a formulation which enables a mixture of diazinon and one or more synthetic pyrethroids to be provided.

o In accordance with this invention there is provided a premix of diazinon and a synthetic pyrethroid, wherein the pyrethroid is S dissolved in the diazinon and wherein additional adjuvants if required are provided to maintain the formulation in a stable state.

S Further in accordance with the invention there is provided a S wettable powder containing diazinon and a synthetic pyrethroid comprising the premix as defined above together with a suitable S inert powder base to provide a wettable powder formulation.

In accordance with the invention there is further provided a process for making a premix containing a synthetic pyrethroid and diazinon, comprising mixing diazinon and the pyrethroid together with the required adjuvants under conditions so that the pyrethroid is added as a liquid to the diazinon.

2 In accordance with the invention, the solvent properties of diazinon are used to dissolve the synthetic pyrethroid. In the process of the invention, since pyrethroids are normally obtained as low melting point solids, to convert them into liquid form, warming of the pyrethroid is required. With permethrin for example, the melting point is just above normal ambient temperature and hence this material can be warmed to about 60"C to achieve a liquid state.

The synthetic pyrethroid can be any suitable pyrethroid which is compatible with diazinon. Permethrin is a good example and is one of the pyrethroids of the invention. Permethrin and other pyrethroids in general will have different wetting characteristics than diazinon. Therefore, to formulate them as a wettable powder in the most effective manner, a different surfactant is required.

\i Surfactants are generally used in the formulations of the invention to provide wettability characteristics and hence enable the formation of a wettable powder and these are generally of the non-ionic type. Non-ionic surfactants are provided having various wettability characteristics generally defined by their ko hydrophilic/lipophilic balance (h/l balance). A number of surfactants known under the trade mark Teric are provide with varous h/l balances. A good surfactant for use with diazinon is S Teric GN9 while a good surfactant to use with permethrin is Teric GN 15. In the process of the invention, the surfactant matched with diazinon is added to the diazinon and mixed therewith prior to addition of the permethrin which is premixed with the surfactant most suitable therefor.

Diazinon is moisture sensitive so that moisture needs to be excluded from the mixing process and the mixture. It is desirable 30 when the premix or other formulation is to be stored to include a :stabiliser which generally acts to scavenge any moisture which be present or be included during the mixing process. The technical grade of diazinon is normally supplied with such a stabilizer, but it is in accordance with the invention desirable to add another 3s stabiliser to the premix. A suitable stabiliser is an epoxidised soya oil, such as that sold under the trade mark Reoplast 39.

3 The process of the invention comprises taking diazinon which is a liquid at room temperature generally in the technical form which contains 91.4% of diazinon, mixing that with the surfactant such as Teric GN9 and the stabliliser Reoplast 39 in a mixer designed y for mixing low to moderate viscosity liquids, such as a paddle mixer. The permethrin technical grade which usually consists of 94.5% of active ingredient is mixed with Teric GN15 or else these two can be separately added with each being warmed to around to melt the permethrin. Mixing of the ingredients will then take 0O place in about 2 hours. If solid permethrin was added, the dissolution thereof into the diazinon would take a much greater period of time.

The permethrin is incorporated into the premix at a low ratio to that of the diazinon. Diazinon is present in a major amount generally at least 10:1 or more desirably 20:1 in comparison to the amount of permethrin.

The premix can be stored or can be made into the wettable powder which can then be stored.

The wettable powder is formed by mixing the premix with an inert ao powder base. The inert powder base can comprise suitable inert inorganic substances such as calcium aluminium silicates which are produced with a high surface area adapted to adsorb liquids, such S as Microcel E or Sipernat. Also present is preferably a dispersing agent such as a lignosulphonate, e.g. that sold under the trade mark Totanin QX or Polyton 0 and finally an inert filler of lower surface area adapted to modify the concentration of the technical ingredients or other ingredients. This will generally have a lower surface area than the adsorbent powder. A suitable material is clay marketed under the name "Clay

C.

o The following example illustrates one formulation of a premix and of a wettable powder and the method of forming the materials.

4 Example A. Diazinon Tech 84.4 Permethrin Tech 4.1 Teric GN9 5.1 S Teric GN15 1.3 Reoplast 39 5.1 100.0 Formulation is effected by mixing Diazinon Tech, Teric GN9 and Reoplast 39 in a paddle mixer designed for medium viscosity liquids and separately adding Permethrin tech and Teric GN15 each warmed to around An inert powder base is formulated to the following specifications: B. Microcel E IS or Sipernat: 76 Totanin QX or Polyton O 18 Clay GM 40 6 100 The final mixture is formulated on a Ribbon Blender as follows: o The Ribbon blender is charged with a load proportional to 41.5% of mixture B. Onto this 58.5% of premix are sprayed, at a rate which prevents clogging or pugging of the mix. The Ribbon Blender is S: then run until the mixture is homogeneous.

While this invention has been described with reference to preferred embodiments, it is not to be construed as being limited S thereto. In addition where specific materials have been described and known equivalents exist thereto, such equivalents are incorporated herein as if specifically set forth.

The claims form part of the disclosure of this specification.

*o

Claims (12)

1. A premix of diazinon and a synthetic pyrethroid, wherein the pyrethroid is dissolved in diazinon,and wherein the premix is in a stable homogeneous state optionally through the addition of one or more adjuvants.

2. A premix in accordance with claim 1 wherein the pyrethroid is Permethrin.

3. A premix in accordance with claim 1 or claim 2 wherein the pyrethroid is first converted into a liquid form by warming before addition to diazinon.

4. A premix in accordance with any one of the preceding claims wherein a surfactant suitable for use with diazinon is first mixed with diazinon before addition of the pyrethroid. A premix as claimed in any one of the preceding claims wherein the pyrethroid is first mixed with a surfactant compatible with that pyrethroid before adding to diazinon.

6. A premix as claimed in claim 4 wherein the surfactant added to diazinon is Teric GN9.

7. A premix as claimed in claim 5 wherein the surfactant added to the pyrethroid is Teric S 8. A premix as claimed in any one of the preceding claims wherein a stabiliser which scavenges moisture is included in the premix. S 9. A premix as claimed in claim 8 in which the stabiliser is an epoxidised soya oil. 6 A premix as claimed in any one of the preceding claims in which the proportion of diazinon to the pyrethroid is at least 10:1.

11. A wettable powder formed by mixing the premix as claimed in any one of the preceding claims with an inert powder.

12. A wettable powder as claimed in claim 11 in which the inert powder is an inert inorganic substance with a high surface area.

13. A wettable powder as claimed in claim 11 in which the inert powder is a calcium aluminium silicate with a high surface area.

14. A wettable powder as claimed in any one of claims 11 to 13 additionally containing a dispersing agent. A wettable powder as claimed in claim 14 in which the dispersing is a lignosulphonate.

16. A wettable powder as claimed in any one of claims 11 to additionally containing an inert filler of a surface area lower than that of the inert powder.

17. A premix substantially as herein described with reference to the example. S" 18. A wettable powder substantially as herein described with reference to the example. i: DATED this 28 November 1991 CARTER SMITH BEADLE Fellows Institute of Patent Attorneys of Australia Patent Attorneys for the Applicant: CIBA-GEIGY NEW ZEALAND LIMITED ABSTRACT Daizinon is a known insecticide and has been used for many years in the control of insects and other pests. The present invention relates to a stable state premix of diazinon and a synthetic pyrethroid, the stable state being optimally achieved through the addition of one or more adjuvants. The invention also relates to wettable powders embodying the premix. 6 Sw 6. a. 91 11 1