JPS6233203B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to an insecticide composition that releases hydrogen phosphide by reacting easily hydrolyzed phosphides with moisture. [Prior Art] Metal phosphides that can be used for insecticidal purposes are mainly calcium phosphide, aluminum phosphide and magnesium phosphide. A problem with these phosphides is that they react violently to varying degrees when they come into contact with water. The temperature increase that occurs concurrently with the reaction may lead to ignition of the hydrogen phosphide generated. Attempts have been made several times to overcome these drawbacks by adding hydrophobic substances. Apart from the known methods of making phosphides hydrophobic, for example by adding metal soaps, paraffins, resins or waxes, the use of silicone resins for this purpose has also already been described. According to German Patent Publication No. 1023265, the addition of silicone can significantly retard gas formation when moisture enters the phosphide. However, this is not a preferred method in terms of practical examples. Rather, it is thought that it is better to suppress the reaction between the phosphide and liquid water by making it hydrophobic, without interfering with the generation of gas due to the action of moisture in the atmosphere. It is being In addition, West German Patent Publication No. 1542877
It is described that the use of liquid hydrophobizing agents provides adequate protection against moisture without interfering with useful properties. More particularly, this can be achieved by applying methyl- or phenyl-silicone oils to the surface of molded bodies, such as tablets. Apart from the fact that the object of this method is limited to molded objects, it was also found that the employment of such silicone oil did not bring about a satisfactory hydrophobizing effect. That is, addition of about 3% of methyl- or phenyl-silicone oil does not result in sufficient hydrophobization. On the other hand, if added in large amounts, the fluidity and pressability of the mixture will be significantly impaired, impeding subsequent normal processing and use. A disadvantage associated with the use of other known hydrophobizing agents is that, for example when using metal soaps, fairly large amounts need to be added to obtain a suitable hydrophobic effect. This, in turn, limits the addition of other important adjuvants needed to suppress autoignition. The flowability and pressability of the mixture is adversely affected by large amounts of additives. Paraffins, synthetic resins and waxes cannot be easily added (by grinding, melting or dissolving) and often have to be pretreated. In that case as well, a relatively large amount of additive is required to obtain a sufficient hydrophobizing effect. For this reason, metal phosphides used for insecticidal purposes can be rendered hydrophobic to the required degree in a simple manner, without impeding the desired access of water vapor.
Moreover, there remains a need for suitable hydrophobization techniques, such that the required amount of hydrophobization agent can be kept as low as possible. [Problems to be Solved by the Invention] The present invention provides an insecticide composition that satisfies such requirements and a method for producing the same, which does not delay the reaction with water vapor, but does not cause phosphorization when it comes into contact with liquid water. The present invention aims to provide a phosphide-based insecticide in which the rate of hydrogen generation is effectively suppressed. [Means for Solving the Problems] The object of the present invention is to solve the problem by using a low molecular weight organopolysiloxane having an active group capable of reacting with a metal phosphide as a hydrophobizing agent. will be achieved. The composition of the present invention is a granular phosphide-based insecticide suitable for the purpose of pest control, which is hydrolyzable and releases hydrogen phosphide when it comes into contact with moisture, and which is thermally decomposable. by the hydrophobizing action of organosilicon compounds in which one or more reactive hydrogen atoms are bonded directly to silicon, which may also contain gas-forming substances and/or other customary additives. This is an insecticide composition that has been made hydrophobic. A suitable organosilicon compound for the insecticide composition of the present invention is a methyl hydrodiene polysiloxane having the general formula: [In the formula, R is a methyl group, p and q are both positive integers, and the total thereof is 10 to 1000, preferably 20 to 100. It is particularly advantageous to use methyl hydrodiene polysiloxane in the form of a low-viscosity oil. This organosilicon compound is prepared at room temperature (i.e. 20
It is preferred to have a viscosity of 10 to 1000 cp at 100°C. The above silicone oil has reactive Si--H bonds that can participate in the reaction reaction. Therefore, the Si--H bond reacts with a compound having a hydroxy group, for example, according to the following formula. 〓Si-H+HOR→〓Si-O-R+H ₂ (Basic substances such as ammonia and amines accelerate this reaction.) Preferably, this hydrophobizing agent is present in the composition or in phosphide particles. Distribute it to the top. The phosphide in suitable compositions is calcium phosphide, magnesium phosphide or aluminum phosphide, preferably the latter. Preferably, all or a substantial portion of the hydrophobizing agent is chemically bonded to the surface of the particulate phosphide. Preferably, the particulate phosphide is industrial aluminum phosphide, such as that used in insecticidal aluminum phosphide formulations. In some preferred embodiments, the presence of the hydrophobizing agent is limited to the surface of the particulate phosphide. In this way, the hydrophobizing agent is effective where it is truly needed in the composition and is not wasted in parts of the composition that do not require protection against liquid water. The oxidation effect is particularly economically exploited. Preferred compositions are those rendered hydrophobic with 0.1-3% by weight hydrophobizing agent, more preferably 0.2-0.5% by weight hydrophobizing agent. According to another form of the invention, particles of metal phosphides of the type selected from calcium, magnesium and aluminum phosphides, particles of ammonium and amine compounds, natural hydrogen phosphides of the type selected from ammonium and amine compounds Pesticide compositions are provided in the form of a mixture of particles of an additive comprising an ignition suppressing chemical and a hydrophobizing amount of a hydrophobic organosilicon compound chemically bonded to the surface of the particles of the mixture. Ru. A preferred composition is a shaped mixture of particles. However, the present invention provides a composition provided in powder form, such as a small pouch, sachet or other container made of paper or other suitable material that is permeable to atmospheric water vapor but preferably repellent to liquid water. It can also be applied to items placed in . Such containers are known per se in the art. The additive particles are preferably a mixture of urea particles and ammonium carbamate particles. Further, according to the present invention, a method for producing the above-mentioned insecticide composition is also provided. The method comprises mixing a phosphide or a mixture of phosphide and an additive composition with said organosilicon compound and subjecting the mixture to conditions such that the compound reacts to hydrophobize the components of the mixture. Consists of. The present invention is based on the surprising finding that excellent results are obtained by using organosilicon mixtures for hydrophobizing metal phosphides. This means that the reactive groups in the organosilicon compound form strong bonds with the metal hydroxyl groups present in industrial phosphides through surface reactions, and that individual phosphides are able to avoid moisture. It has been found that this can be explained, at least in part, by the formation of crystals during the production of phosphides due to difficult reactions. For this reason, the organopolysiloxane molecular chains are oriented so that the surface of the crystal is covered with methyl groups arranged outward.
As a result, an excellent hydrophobic effect is brought about. The reactions that appear to occur during hydrophobization are:
Temperature for example 80~200℃, preferably 110~150℃
C. and/or by adding suitable catalysts.
Such catalysts include ammonia, ammonium compounds or amine compounds, such as ammonium carbamate or ammonium carbonate, which are 0.5 to 3
It can be used in amounts of % by weight. Catalysts include organometallic compounds. Examples of suitable catalysts are:
Compounds of lead, tin, zirconium, cobalt or titanium are particularly suitable, for example zirconium butoxide, dibutyl tin,
dilaurate and di-n-octyl tin maleate. These catalysts are used in particular in amounts of about 1 to 10%, based on the organosilicon compound. A particular aspect of the invention is the method by which an excellent and effective hydrophobization of metal phosphides is achieved by the use of organosilicon compounds without the use of special treatments or additives. For the purpose of suppressing self-ignition of hydrogen phosphide generated by hydrolysis in a metal phosphide-containing insecticide composition, additives that generate NH ₃ such as urea, ammonium carbonate, ammonium carbamate, or amines may be added. It is preferable that it be contained. These additives are uniformly distributed in the composition in the form of particles. These substances promote the reaction of the organosilicon compounds only if they are added in such a way that it is appropriate to add them during the preparation of the mixture in order to obtain the desired hydrophobicity. Even immediately after this preparation, the product has hydrophobic properties, which properties are further enhanced during subsequent processing and storage. The composition can be pressed into shaped bodies such as tablets or pellets. The molded body has a porosity that allows moisture in the atmosphere to approach the hydrophobic metal phosphide. There is no "bursting effect" on the approach of moisture, as seen with any water-repellent coating proposed so far. The hydrophobization treatment according to the present invention includes:
While providing the desired protection against liquid water, it has not been found to reduce in any degree the desired rate of generation of phosphin by the hydrolytic action of atmospheric moisture. However, according to a special embodiment of the process, the particulate phosphide is simply mixed with the organosilicon compound, optionally with the addition of an appropriate amount of catalyst,
The organosilicon compound is reacted until all or substantially all of the phosphide particles are bound, thus rendering the particles hydrophobic. As further additives, urea and/or ammonium carbamate can also be added in amounts that suppress spontaneous combustion. Initially, only a catalytic amount of a material such as ammonium carbamate is added, which largely or completely volatilizes during the hydrophobization reaction. (The resulting ammonia vapor also acts as a catalyst.) For example, the catalytic amount of ammonium carbamate at this stage is 0.5-3% by weight based on the metal phosphide, but additives (e.g. carbamic acid The final content of ammonium (ammonium and urea) is preferably high, between 10 and 50% of the composition, especially between 20 and 35%, for example 30%. This final product is preferably pressed into shaped bodies such as tablets or pellets. In this way, the hydrophobizing effect is wholly or substantially localized to the metal phosphide particles, and protection against liquid water is effectively provided without interfering with the desired access of water vapor. The fact that very small amounts of organosilicon compounds are sufficient to strongly hydrophobize metal phosphide-containing formulations was also surprising. To obtain a similar hydrophobizing effect, 10 to 30 times the amount is required when using known silicones, and up to 100 times when using other solid hydrophobizing agents. It may even require For the hydrophobization of customary metal phosphide-containing preparations suitable for insecticidal purposes, on the basis of mixtures with phosphides or other additives that may be present.
It has been found that 0.2-0.5% of organosilicon compound is quite sufficient. Additions as small as 0.1% already provide sufficient hydrophobic properties for many purposes. Only in exceptional cases will it be desirable to use higher proportions of organosilicon compounds, up to about 3%, based on the final product. As is clear from the above description, another form of the present invention is a type of industrial metal phosphorus suitable for pest control and capable of generating hydrogen phosphide by reaction with moisture under pest control conditions. chemical particles, in which an organosilicon compound in which one or more reactive hydrogen atoms are directly bonded to silicon is reacted on the surface of the particles to produce a chemical bond of a hydrophobic reaction product. There are particles that are made hydrophobic. Similar features as described above apply for organosilicon compounds. Again, the preferred metal phosphide component is technical aluminum phosphide. The following examples will serve to illustrate the invention without limiting its scope. Example 1 70 parts of technical AlP were finely ground and mixed with 10 parts of finely powdered ammonium carbamate and 19.5 parts of ground urea. During mixing, 0.5 part of methyl hydrogen polysiloxane (Goldschmidt, West Germany) methyl silicone oil MH15 having a viscosity of about 15 cp and containing 35 to 40 hydrogen atoms with a degree of polymerization of 40 to 45 is added. Ta. The total mixing time was 30 minutes. A free-flowing powder is obtained;
This could be pressed into compacts without further additives. The properties of such molded bodies are shown in the table and in which they are compared with tablets obtained according to the prior art. Example 2 99 parts of technical grade AlP were mixed with 0.9 parts of the above methyl hydrodiene polysiloxane in a mixer for 15 minutes. Then 0.1 part of zirconium butoxide was added and mixing continued for an additional 15 minutes. A free-flowing hydrophobic phosphide free of fines was obtained. Example 3 2 parts of the above methyl hydrodiene polysiloxane were added to 98 parts of AlP. This AlP is produced by a thermal reaction of Al and P, and
Once the phosphide had cooled to about 160°C, it was mixed and then ground. The phosphide exhibited significant hydrophobicity after cooling. Experiment 1 70 parts of phosphide hydrophobized according to Example 2 or 3 were mixed with 20 parts of urea and 10 parts of urea by known methods.
of ammonium carbamate and then
Pressed into 18 mm diameter tablets. Tablets of the same composition but made using a pretreated phosphide were used for comparison. To test water repellency, a drop of water was placed on the surface of the tablet. The tablets according to the prior art reacted immediately with water, but
The water on the surface of the tablets according to the invention remained intact for a long time. A slow reaction begins after about 10 minutes,
It wasn't finished even after 30 minutes. Experiment 2 The table shows the effect of using the methyl hydrodiene polysiloxane according to the invention. There, the average pH of various metal phosphide-containing molded bodies weighing 3 g each is brought into contact with liquid water at 20°C.
₃ incidence rates are shown. For this purpose, according to the principle of a pneumatic trough, a graduated cylinder with a volume of 250 ml was filled with water, turned upside down, and stood in a tank filled with water and devoid of air. When a tablet containing hydrolysable phosphide is placed under a graduated cylinder, the amount of gas released from the water is measured in ml as a function of time. The smaller the amount of gas released per unit time, the stronger the hydrophobic effect. For comparison, measurement results for molded bodies obtained using methyl siloxane oil and aluminum stearate that do not contain reactive hydrogen atoms are shown.

[Table] The hydrophobizing effect obtained according to the invention has the additional important effect of being very permeable to water vapor. In pest control using the formulations according to the invention, this is particularly advantageous in that the evolution of gas from the phosphides is not hindered, meeting the requirement for formulations with a short shelf life of activity. Experiment 3 As is clear from the table, the tablets produced according to the present invention do not lose their gas-generating ability, unlike the formulations made hydrophobic using paraffin wax. For this purpose, various tablets are prepared at a relative humidity of 40
Relative to that of the initial residual amount of available hydrogen phosphide exposed at 20 °C to air with ~60%
Analyzes were performed at the times indicated in the table.

〔Effect of the invention〕

According to the present invention, a phosphide-based insecticide composition that is resistant to water exposure can be obtained without inhibiting the generation of hydrogen phosphide by water vapor.

Claims (1)

[Scope of Claims] 1. An insecticide containing a granular phosphide selected from the group consisting of calcium phosphide, aluminum phosphide, and magnesium phosphide as a main ingredient and a small amount of additives, which has the general formula [In the formula, R is a methyl group, p and q are both positive integers, and the sum of them is 10 to 1000. ] An insecticide composition that has been made hydrophobic by the hydrophobizing action of methyl hydrodiene polysiloxane. 2. The insecticide composition according to claim 1, wherein the sum of p and q is 20 to 100. 3. The insecticide composition according to claim 1 or 2, wherein the methyl hydrodiene polysiloxane has a viscosity of 10 to 1000 cp at room temperature. 4. The insecticide composition according to claim 1, which contains a spontaneous ignition suppressor selected from ammonium compounds and amine compounds as an additive. 5 A granular phosphide or a granular mixture of phosphide and an additive is prepared by the general formula [In the formula, R is a methyl group, p and q are both positive integers, and the sum of them is 10 to 1000. ] A method for producing an insecticide composition, which comprises mixing the composition with a methyl hydrodiene polysiloxane having the following: and placing the mixture under conditions that allow the mixture to react. 6. The manufacturing method according to claim 5, wherein the reaction conditions are heating conditions of 80 to 200°C. 7. The manufacturing method according to claim 5, wherein the additive is a reaction promoting catalyst. 8. The production method according to claim 7, wherein the reaction promoting catalyst is ammonia, an ammonium compound, or an amine compound. 9. The method according to claim 7, wherein the reaction promoting catalyst is an organometallic compound.