DE2450257A1 - INSECTICIDE - Google Patents

Description

BASF Aktiengesellschaft rn ^ tzi

Our sign; O "Ζ.50 919 Sws / Wn 67ΟΟ Ludwigshafen, 10/22/1974

insecticide

The present invention relates to an insecticide made from a polyethylene felt impregnated with a phosphoric acid ester.

It is known to use insecticides made from a cellulose felt exist, which is impregnated with a phosphoric acid ester (DT-OS 2 028 226). They have the disadvantage that the Active ingredient decomposes quickly.

It has been found that insecticides do not have this disadvantage, which contain a polyethylene felt with a phosphoric acid ester is soaked.

The phosphoric acid ester used is 0,0-dimethyl-0- (2,2-dichlorovinyl) phosphate preferred.

The preferred polyethylenes are partially crystalline polymers of ethylenics having 2 to 8 carbon atoms. Suitable partially crystalline polyethylenes have an X-ray crystallinity of more than 5 percent by weight at a temperature of 25 ° C. Polyethylenes whose densities are between 0.915 and 0.965 g / cm are preferably used. The molecular weight of the polyethylenes is characterized by the melt index, the melt index (measured at a temperature of 190 ⁰ C and an applied weight of 21.6 kg) ranging from 0.01 g / 10 min to 100 g / 10 min. The melt index is according to ASTM D 1238-65 T determined. The polyethylenes are produced by the known high and low pressure polymerization processes. They are known.

Pibrils are made from polyethylene by dissolving them of a polyethylene in an organic solvent

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Pressure at temperatures above the crystallite melting point of the polymer and relaxation of the solution through a narrow nozzle opening into a room under lower pressure. This relaxation space contains a gaseous medium (e.g. Nitrogen) or a liquid medium (water or an organic solvent).

For example, the polyethylene fibrils are produced in the following manner

Regulation 1

In a pressure vessel equipped with a stirrer, 14 parts of a linear polyethylene, which has a density of 0.96 g / cm, a melt index of 4.5 g / 10 min (19O ° C / 2.16 kg) and a melting point of 130 ⁰ C, has consists in a mixture of 51.6 parts of light petroleum (b.p. 65 to 95 ° C) and 34.4 parts of pentane of 80 parts of n-pentane and 20 parts isopentane, dissolved at 165 ⁰ C . A pressure of 18 to 20 atu develops. This solution is then expanded tangentially via a pipeline which has a length of 120 cm and an internal diameter of 4 mm into a cylindrical space which is charged with the same solvent mixture in which the polymer is dissolved. The opening of the tube through which the relaxation takes place is below the surface of the liquid. This boils under reflux, whereby excess heat is removed via a cooler. The fiber mash is continuously discharged with the help of an overflow. If the relaxation area is 30 cm in diameter and 50 cm high, this overflow is installed in such a way that a constant liquid level of approx. 15 cm is maintained.

The fiber mash is largely freed from adhering solvent by filtration »The remaining solvent is removed in a dryer with the aid of a stream of nitrogen at a temperature of 40 to 45 ° C. You get a soft one loose fiber product (bulk density l8 g / l), which is loosened with the help of a card to a product with a cotton structure

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which has a bulk density of 10 g / l »The fiber length lies between 5 and 25 mm, the fiber thickness between 3 and 6 μm. A specific surface area of 11.2 m 2 / g and a Schopper-Riegler value of 24 ° SR for the degree of fibrillation are determined.

Regulation 2

The procedure is as in rule 1 and is from the same starting materials, a Polyäthylenlösung in a light naphtha-pentane mixture ago, the 15 weight percent polymer contains "This solution is at 165 ⁰ C under a pressure of l8 atm to 20th The solution is relaxed through a pipe that is 5 mm long and 6 mm in diameter, tangentially into a cylindrical space 3 ^{m in} diameter and 1 m in height. This space is at the top of a vertical 3 m pipe Diameter and 6 m length, which is cooled. The solvent evaporating during the decompression condenses on these cooling surfaces. The fibers fall through a concentric, perforated inner tube with a diameter of 2 m. In countercurrent, nitrogen at approx. 60 ° C is passed through the pipe arrangement, at the lower end of which the fibers are discharged. The fibers are loose and soft with a bulk density of 15 g / l and are practically free from solvents. Their lengths are 3 to 25 mm, their thicknesses 5 μm. The short fibers have a specific surface area of 10.2 m / g and gave a Schopper-Riegler value of 21 ° SR.

Regulation 3

In a pressure vessel with a stirrer 14 parts of a linear polyethylene having a density of 0.96 g / cm, a melt index of 4.5 g / 10 min (l90 ^o C / 2, l6 kg) and a melting point of 130 ⁰ C has, in a mixture of 51.6 parts of light petroleum (b.p. 65 to 95 ° C) and 34.4 parts of pentane of 80 parts of n-pentane and 20 parts isopentane, dissolved at 165 ⁰ C. A pressure of 18 to 20 atmospheres develops. This solution is fed centrally from above through a two-substance nozzle into a filter hose made of Perlon filter fabric with a mesh size

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of 0.5 mm relaxed, the diameter of 2 m and one Length of 6 m and hanging in a room filled with nitrogen at atmospheric pressure: and at a temperature of 40 ° C o The two-substance nozzle consists of 2 concentric tubes, the inner tube having an outer diameter of 6 mm and an inner diameter of 4 mm »encloses the outer tube the inner tube and leaves an annular gap 0.75 mm wide free, through which nitrogen is released, which is released is taken from a storage container which is under a pressure of 20 atmospheres. At the lower end of the filter hose this will be Paser product continuously discharged «, The nitrogen Discharged solvent vapors are condensed by cooling and fed back into the process. The nitrogen is compressed and fed back to the two-substance nozzle via the storage container «

The fiber product obtained has a bulk density of 10 g / l. It is obtained practically free of solvent. the Short fibers have a length of 0.5 to 20 mm and a diameter from 3 to 30 µm and the same in their degree of fibrillation lightly ground cellulose fibers. It became a Schopper-Riegler value measured from 20 ° SR.

The polyethylene fibrils are similar in size and shape to cellulose fibers. They have a length of 0.5 to 30 mm and a thickness of 3 to 6 µm. Compared to the synthetic ones Fibers obtainable staple fibers they are characterized on the one hand by a relatively large specific surface (1 to 80 m / g) and on the other hand through their ability to form sheets (fleece, felt) when separating the hydrophilized Aqueous suspension fibrils on a sieve.

Aqueous suspensions of polyethylene fibrils are for example produced by introducing the inherently hydrophobic fibrils into water with stirring in which a dispersing agent is dissolved in an amount of 0.1 to 1.0 percent by weight based on the dry weight of the fibrils. Of the obtained pulp is then 5 to 15 minutes with

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reworked a high-speed propeller stirrer »The consistency here is generally 0.5 to 10 and preferably 1 to 5 % o

Suitable dispersants are, for example, melamine-formaldehyde polycondensates, those by polycondensation of melamine / formaldehyde and aminocarboxylic acids or their alkali salts be prepared in aqueous solution »In addition, up to 1 percent by weight can be used as a dispersing aid on the dry weight of the polyethylene fibrils, use an anion-active protective colloid «Suitable anion-active Protective colloids are, for example, condensates of formaldehyde and the sodium salt of ß-naphthalenesulfonic acid, Polycondensates from urea, formaldehyde and the sodium salt of phenolsulfonic acid, urea-formaldehyde polycondensates modified with sodium bisulfate or melamine-formaldehyde polycondensates modified with sodium hydrogen sulfite, alkali salts of carboxymethyl cellulose, copolymers of maleic acid and vinyl isobutyl ether and ammonium salts of copolymers made of styrene and acrylic acid.

The listed dispersants for the hydrophobic polyethylene fibrils are highly effective, so that only minor Quantities are required for the production of aqueous suspensions and the hydrophilized fibrils their high adsorption • rermögen keep.

The aqueous suspensions of polyethylene fibrils can after appropriate further dilution with water on a Paper or wet fleece machine to paper or textile-like ones Flat structures (felts) are processed. The weight per unit area of the felts made of polyethylene fibrils can be varied within wide limits vary. Felts with a have particularly proven themselves

ο
Weight per unit area from 200 to 1000 g / m.

The felts made of 100 % polyethylene fibrils are characterized by good fiber bonding and high dry and wet strengths. These beneficial properties are only achieved if the fibrils are sufficiently fibrillated (crimped). '

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The pibrillation of the pibrils can be determined, for example, by determining the degree of grinding according to the Schopper-Riegler method (Korn-Burgstaller, Handbuch der Materialprüfung, pp. 388 ff., Springer-Verlag). For carrying out this determination, the short fibers must be treated with dispersants, and in an aqueous suspension with constant material density (2 g / l and 20 ⁰ C) are brought. The amount of water that is retained by the suspended short fibers under certain conditions is determined. The amount of water absorbed (° Schopper-Riegler, ° SR) is greater, the higher the pibrillation of the pibrils. The Schopper-Riegler values of fibrils made from polyethylene, which provide mechanically stable fungi, are, for example, from 15 to 30 ° SR (dispersant; for example the sodium salt of carboxymethyl cellulose).

For processing polyethylene fibrils into polyethylene felts on the paper machine it is also necessary that the webs have a sufficiently high initial wet strength. A standard sheet (2.4 g) made from polyethylene fibrils must have a water content of 83 percent by weight have an initial wet strength of at least 80 g.

The initial wet strengths are determined with the test device developed by W. Brecht and H. Piebinger (Karl Frank, Taschenbuch der Papierprüfung, 3rd expanded edition, Eduard Roether Verlag, Darmstadt, I958, page 59). From the ones to be examined Fibrils are formed on a sheet-forming device by placing a frame of test strips with the dimensions 30 χ 95 mm. The thickness of the test strips (basis weight) is determined by the weight of the material. With the test device the load in g at which the test strip tears is then measured.

According to the manufacturing processes listed above, fibrils are obtained, which are the prerequisites for dynamic web formation on the paper machine, because the initial

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Wet strengths of norm sheets from these fibrils lie between 100 and 10 g with a water content of 83 percent by weight .

The polyethylene felts are ideal as a carrier for biologically active substances. Particularly liquid active ingredients or High-percentage solutions of active ingredients are in large quantities in the cavities between the individual polyethylene fibrils consist in the polyethylene felts, adsorbed.

The adsorptive capacity of polyethylene was determined in the following way: From polyethylene of the type described was on the one hand a film of 2 mm thickness and on the other hand a felt of the same thickness. Samples of these moldings were made hung in 0,0-dimethyl-O- (2,2-dichlorovinyl) phosphate until the The constant weight of the shaped bodies indicated that maximum adsorption had occurred. The weight gain was im In the case of the film 0.0185 g / g polyethylene, in the case of the felt 6.377 g / g polyethylene. This experiment clearly shows that higher adsorption on the felt as a result of the greatly enlarged surface of this shaped body compared to the film. Of the Polyethylene does not dissolve the active substance.

These excellent properties of the polyethylene felts show in their ability to use biologically active substances high vapor pressure after their adsorption over a long period of time to vaporize continuously, which is particularly effective for combating of insects in buildings is of interest. The biological effectiveness of these insecticides is equal to that already known, corresponding insecticides used in practice.

A particular advantage of polyethylene felts over, for example, the known cellulose felts is that the former are practically anhydrous, while the latter usually contain a few percent water. The polyethylene felts contained 0 to 0.01 % water and the cellulose felts 2.6% water. The latter must therefore be dried before being soaked with the mostly hydrolysis-sensitive active ingredients,

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which is very difficult as they hold the water very tight. The water content of cellulose felts changed in the Drying in the following way

Starting salary; 2.60 % water

after 60 hours at 80 ° C; 0.70 % water

After an additional 48 hours at 10O ⁰ Cs 0.50% water after a further 72 hours at 130 ⁰ C: 0.36% water.

Since felts treated in this way are almost hygroscopic, they can only be handled in desiccators or absolutely dry room air which makes handling very difficult.

In an experiment, the storage stability of 0,0-dimethyl-O- (2,2-dichlorovinyl) -phosphate was determined at elevated temperatures depending on the felt material that a final water content of 0.36 f> were dried as described above, with non-dried Polyäthylenfilzen (water content 0.01 fo), which were impregnated with the same active ingredient compared (sample B). The active ingredient was determined by gas chromatography by exhaustively extracting a felt at each of the times mentioned and determining the total active ingredient content of this sample.

example A. Storage temperature
40 ⁰ C
B. Analysis according to
(Days) 5.75g = $ 100 5.8g = 100 $ 5.7 O 100.0 fo $ 100.0 4th 100.0 % $ 100.0 10 ■ $ 97.0 $ 100.0 30th $ 85.5 100.0 % ■ 60 $ 76.5 $ 97.4 90 72.4 % 96.6 % 120

50 ° C. B. A. 5.8g = 10 5g = $ 100 95.7 % 100.0 $ $ 91.6 84.3 % $ 91.0 83.0 $ $ 91.0 71.0 $ $ 89.0 38.0 $ 83.8 % 24.0 $

The result of the experiment shows the superior stability of the insecticide according to the invention compared to a known insecticide. 609818/1059 _{or similar}

Claims (1)

- 9 - O.ζ. 30 919 Claims ίί) Insecticide based on a carrier which is soaked with a phosphoric acid ester, characterized in that the carrier is a polyethylene felt » 2p insecticide according to claim 1, characterized in that the phosphoric acid ester is 0,0-dimethyl-0- (2,2-dichlorovinyl) phosphate » BASF Aktiengesellschaft 609818/1059