DE1077580B - Process for coating surfaces with a paint containing a pest repellent - Google Patents

Description

Method of coating surfaces with a pesticide The invention relates to a process for coating of surfaces with a paint containing a pesticide solvent-based, which forms a film-like coating after drying. In the context of this description, the term »pesticides« all suitable for the destruction of insects, bacteria, molds and the like Poisons are understood.

It is known to produce aqueous spray liquids that a certain amount of a water-soluble condensation product of the urea-formaldehyde or of the melamine-formaldehyde type, a pesticide and hardener, especially ammonium salts. The hardener can also be absent. The condensation product serves as a binder to increase the adhesion of the control agent to the dusted Substrate when the water has evaporated. Such aqueous dispersions are mainly used for spraying plants and for pest control of plant crops used. When used as watercolors for painting building walls or other Surfaces are used to cover this with a thin layer of pesticide to be coated, the resulting coatings prove to be porous and moisture-permeable and can in terms of durability, impermeability and wear resistance cannot be compared with lacquer-like coating films.

British patent 605 960 describes the manufacture of paints and protective coating compositions with insecticidal effects by dissolving dichlorodiphenyl-trichloroethane in air-drying, film-forming synthetic resins, e.g. thermoplastic Resins, alkyd resins modified with drying oils and copolymers between Styrene and drying oils that are dissolved in organic solvents, which dissolve the insecticide at the same time. This gives coatings in which the Excess of insecticide and also a certain amount of the insecticide Resin dissolved insecticide crystallizes on the surface, creating a has a high poisonous effect against insects.

In Soap and Sanitary Chemicals, February, March and April 1948, S. S. Block the testing of a number of film-forming substances with insecticidal substances coating masses and observed that amino resins soluble in organic solvents have properties as film-forming carriers for crystalline organic insecticidal properties, which favorably influence their crystallization. However, there is a disadvantage to such Aminoplast resins that they are used for the production of oven-drying paints, in which the resin by heating, preferably to temperatures above 100 ° C, is polymerized and cured while drying under normal conditions of air do not produce coatings of sufficient hardness.

When examining the pest-killing properties of coatings, those made from amino resins soluble in organic solvents in conjunction with Substances. -Of known toxicity to pests have been produced found that the toxicity of the oven dried coating when used of di.chlor-diphenyltrichloroethane adversely affected by the increase in hardness will. It has also been found that the hardness of the coating has a important influence on the amount and extent of crystal growth and crystal clearing exercises. That is an important factor in making coatings that are not only "initially show high toxicity to pests, but also after repeated Cleansing, annealing, should produce crystals, so that. the poisonous Surface is repeated over and over again. Furthermore, the compulsion the paint in the oven too dry, generally the application of such coating compounds Areas that can be heated directly or by thermal radiation, d. H. on transportable Objects that can be placed in drying ovens and on materials that support the Withstand the heating process. The practical difficulty of large areas, such as the interior of buildings to be heated evenly to a sufficiently high temperature, is obvious. The difficulty of oven drying is also easy to see of different substances and objects with very different shapes and size to achieve a uniform film hardness. Another disadvantage is that volatile pesticides under the influence of oven drying easily disappear from the film.

An object of the present invention is therefore to be durable and Produce washable lacquer coatings, in addition to being decorative and protective Properties have a surface with a pest-killing effect.

Another object of the invention is to provide suitable plasticized protective coatings to produce, which from soluble in organic solvents aminoplasts and Pesticides exist and are tough enough to withstand the abrasion to oppose, but also not so hard, to the superficial, gradual and prevent progressive efflorescence or migration of the pesticide, whereby the pest-killing surface is repeatedly renewed or regenerated becomes, especially after cleaning. This creates a high degree of toxicity to Pests persist for a long time until the pesticide content or reserve is completely exhausted within the film. This way the need becomes frequent repainting is reduced or avoided.

The invention consists in that one to a paint with a butvlated urea-formaldehyde resin as a binder and an oil-modified alkyd resin As a plasticizer, an acidic hardener is added shortly before the mass is used, herewith the surfaces to be treated are coated and then dried at room temperature.

After evaporation of the solvents, the remaining film hardens or resin bodies with the pesticide under the influence of the accelerator due to aging.

Organic solvent soluble amino resins suitable for use Suitable in the process of the invention are resins that are formed by condensation from urea, formaldehyde and butyl alcohol.

Alkyd resins with a low or medium oil content are used as plasticizers Use. Particularly suitable alkyd resins of the above composition with a plasticizer effect are with the addition of non-drying oils such. B. castor oil.

Also drying olalkyd resins with a low oil content that usually can be used for the production of oven-drying coatings, the alkyd resin at the same time as a plasticizer and together with the aminoplast resin is used to make a solid film. Several such plasticizers can also be used to be used.

The proportions of the plasticizer (s) to the urea-formaldehyde resin can be varied within certain limits and will change with use of different plasticizers in each case according to their different types Change properties. When using the aforementioned synthetic resins, the proportions for the production of air-drying coatings with sufficient hardness within the scope of the Process according to the invention between 0.25 to 4.0 parts by weight of one with castor oil modified alkyd resin to one part by weight of a butylated urea-formaldehyde resin vary.

Examples of pesticides within the scope of the invention Method that can be used are: a) y-benzene-hexachloride, b) dichloro-diphenyl-trichloroethane, c) 1,2,3,4,10,10-hexachlo, r-1,4,4a, 5,8,8a-hexahydro-1,4,5,8-di-endomethylene-naphthalene ("Aldrin"), d) 1,2,3,4,10,10-hexachloro-6,7-epoxy-1,4,4a, 5,6,7,8. 8 a-octahydro-1,4,5,8-dimethylene-naphthalene (»Dieldrin«), esterified with a mixture of cis and trans Chrysanthemum monocarboxylic acid (»Allethrin«), f) organic mercury compounds, g) dinitro-o-cresol, h) ethyl mercury thiocyanate, i) lactic acid.

These substances do not need to be present in high purity and can also be used mixed if necessary. Commercially available Substances are used that contain or represent the above substances.

Aldrin and Dieldrin are names used by the Inter Departmental Commission an Pest Control "by the United States Department of Agriculture (Chem. Abstracts, XLIV, 1950, p. 7009), as well as Allethrin.

Examples of hardeners and accelerators for producing the Gelation and hardening of the paint film that remains after the solvent has evaporated or resin bodies are acids that are soluble and stable in alcoholic solvents are, such as B. sulfuric acid, hydrochloric acid, ethylsulfuric acid and phosphoric acid.

Acids with a dissociation constant of of the order of magnitude of phosphoric acid or above.

The concentration of the solution of the hardener or the amount of to hardening agent used can take into account the durability of the paint and the Drying or curing time of the coatings produced therewith can be varied, with the use of smaller amounts of acids will increase the shelf life and hardening slow it down. The amounts of curing agents can (based on the total dry weight resin and plasticizer) in the case of a strong acid, e.g. sulfuric acid, 0.2 and more percent by weight or in the case of weaker acids, for example for phosphoric acid, vary between 1 and 6 percent by weight.

Solid or liquid can also be used in the cold-curing coating compositions Pesticides are introduced that are noticeably volatile and during oven drying or heat curing largely through sublimation or evaporation would disappear from the film, whereas during the cold curing and aging process these substances are initially retained and gradually released over time. It is therefore within the scope of the invention, pesticides to use which is usually neither a crystalline character still have the crystal outgrowth and dislocation described above, which but a gradual release or deposition as the coatings age experienced by blooming or evaporation. Benzene hexachloride is an example of one crystalline material which is somewhat volatile and blooms in the coating through gradual crystal growth and simultaneous deposition through evaporation shows.

The paint solvents can be made from esters, aliphatic and aromatic Hydrocarbons, ketones, ethers and alcohols exist, but in general should be an amount of at least 20 weight percent total weight of solvent by a primary alcohol such as B. n-butyl alcohol can be formed to good To achieve storage stability. Maintains a constant amount of hardener A greater amount of primary alcohol in the paint solvents will reduce the shelf life of the Extend paint solution.

Coating compositions produced according to the invention can be applied to the conventional Wise applied, for example by dipping, spraying or painting by means of brushes or paint rollers, on porous or non-porous surfaces.

They can also be applied to textiles by dipping or padding processes to impregnate them or only to cover them superficially. With porous Fabrics, such as mortar or wood, should be primer or topcoat, as they normally would When painting or decorating, applied first, or the covering compounds can receive a first coating with or without the addition of pest toxins, the to gel and harden - over what another coating of the pest-poisonous Paint is applied.

About reactions of metals with the accelerator or the pest poison To avoid this, it is advisable not to apply this directly to the metals. In the case of metals, the usual pretreatment, such as. B. degreasing, pickling, Etching, or phosphating, a primer can be applied to the resistor to increase against contact corrosion and to improve the appearance. Becomes the pest poisonous Varnish is applied to surfaces that have already been painted, so it may be necessary after Apply a second layer of varnish after drying to maximize the toxicity reach.

Of course, fillers and pigments can also be used in the coating or dyes are stored.

In the following exemplary embodiments, all amounts are given Parts by weight represent. Example 1 24 parts of dichloro-diphenyl-trichloroethane (abbreviated DDT) are dissolved with stirring in a mixture of the following composition: 100 parts of a solution of 60 parts of butylated urea-formaldehyde resin in n-butanol, 100 parts of a solution of 60 parts of an alkyd resin modified with castor oil in xylene and 100 parts mixed paint solvent consisting of 55 parts by weight n-butanol and 45 parts of xylene.

10 parts of a one part sulfuric acid and 9 parts n-butanol existing solution are mixed with 162 parts of the above varnish. The one made in this way Air-drying and pest-poisonous coating composition was on a plate E made of tinplate sprayed on and the paint film dried in the air at room temperature (15 to 22 ° C).

For comparison purposes, the above paint was sprayed onto several tinplate plates without the addition of the acidic accelerator, which were then dried in an oven under the following time and temperature conditions. This resulted in hard, wear-resistant coatings. Plate A ... dried in the oven at 145 ° C for 120 minutes.

Plate B ... dried in the oven at 145 ° C for 60 minutes. Plate C. . . Dried in the oven for 30 minutes at 145 ° C. Plate D. . . Oven dried for 20 minutes at 145 ° C. All panels were stored for 14 days inside the building at room temperature for aging. After this time, plate E showed significant efflorescence of DDT crystals on the paint film, while oven-dried plates A, B and C showed no crystals and plate D only showed traces of superficial crystallization.

The toxic effect of the coatings was then examined by exposing meal beetles (Tribolium) to the surface for 24 hours. The following table shows the percentage of meal beetles killed after this contact time and, in a second column, the appearance of the plates after 1/2 years of aging ° / o in Plate 24 hours appearance after 6 months No killed Flour beetle A 13 No crystallization B 14 No crystallization C 15 No crystallization D 54 Weak crystal growth E 100 Dense crystal efflorescence Example 2 A pest-toxic paint was prepared by dissolving 38.4 parts of DDT in a mixture of the following composition: 160 parts of a solution of 96 parts of an alkyd resin modified with castor oil in 64 parts of xylene, 160 parts of a solution of 96 parts of butylated urea resins in 64 Parts of xylene, 20 parts of butanol and 60 parts of xylene.

Immediately before use, approximately 27 parts are made from one 10% sulfuric acid-butanol solution existing accelerator intimately with the Varnish mixed. This varnish was then applied with a brush to parts of wooden stakes applied and completely air-dried. These piles were 3 months sunk for a long time in an estuary where barnacles began to settle. To 3 months ago it turned out to be on the parts with the above pest-killing Lacquer was painted, no barnacles had settled, while the other parts the stakes were badly affected.

EXAMPLE 3 A basic lacquer composition was produced by intimately mixing the following ingredients: 50 parts of aldehyde resin modified with castor oil, 50 parts of butylated urea-formaldehyde resin, 6 parts of butanol and 24 parts of xylene.

a) 12 parts of "Aldrin" were mixed with 130 parts of this basic lacquer and stirred until everything was resolved.

b) 12 parts of γ-benzene hexachloride were added to 130 parts of the base paint (90%) added and dissolved by stirring.

c) To 130 parts of the base lacquer are 12 parts of dichloro-diphenyl-trichloroethane (70%) added and stirred until dissolved.

d) 12 parts of »Dieldrin« are added to 130 parts of the lacquer base and stirred until dissolved.

Immediately before use, 10 parts of a 10% sulfuric acid-butanol solution are added to 142 parts of each of the paints a), b), c) and d) prepared in this way, the mixture is stirred well and the paint is poured onto steel plates which are then dried at room temperature let.

After aging for 6 days at room temperature, the toxicity of the plates to young houseflies was determined by keeping them on the plates under Petri dishes. The times after which 950 / e of the flies were killed are given in the table below. As before, after the plates had been kept in the laboratory for 370 days, the time after which. 95% of the flies were killed, namely a) without removing all or part of the efflorescence and b) after cleaning the surface and removing the surface crystallization with petroleum ether and drying. The results are as follows, with all experiments being carried out twice. Time to kill 95% of house flies (Musca) Plate pest test after 370 days No pesticide test after a) before b) after 6 days cleaning cleaning Minutes Minutes Minutes a) Aldrin .......... 71 80 53 a) Aldrin .......... 71 68 47 b) y-benzene-hexa- chloride ....... 16 20 17 b) y-benzene-hexa- chloride ....... 20 20 15 c) DDT ............ 103 20 32 c) DDT .......... 68 27 31 d) Dieldrin ........ 63 43 65 d) Dieldrin. . . . . . . . 63 43, 65 Example 4 A pest-toxic paint was produced by dissolving 6 parts of aldrin and 6 parts of dieldrin in a solution of the paint binders according to Example 3 in 27.5 parts of butanol and 22.5 parts of xylene. Immediately before use, an accelerator consisting of a 10% sulfuric acid-butanol solution was added in a proportion of 38 g per kilogram of the paint. This paint was used to paint the walls, ceilings and floors of the kitchen, utility and storage rooms of a ship that is often infested by cockroaches (Blatella Germanica) and house flies (Musca Domestica). The following day over 100 cockroaches and 20 houseflies were killed, the surviving cockroaches disappeared. After 4 months: during which the ship was on a long voyage and called at a number of seaports, there was no sign of a new cockroach infestation.

Example 5 Five pest-toxic paints are prepared, each by dissolving 12 parts of DDT in a mixture of 22.5 parts of xylene and 27.5 parts of butanol, followed by each of these solutions containing 100 parts of the following mixtures of butylated urea-formaldehyde - Resin and alkyd resin modified with castor oil is added: Urea alkyd resin Paint formaldehyde resin parts Parts 1 20 80 2 40 60 3 50 50 4 60 40 5 80 20 10 parts of an accelerator consisting of 1 part sulfuric acid and 9 parts butyl alcohol are added to each of the five paints prepared in this way and the paints are poured onto glass plates, which are drained off and left to dry for 7 days at room temperature (15 to 22 ° C.). After light rubbing, crystalline efflorescence formed on the panels, which were then stored inside the building for 4 months. After this time, the efflorescence was removed with xylene and the plates rubbed again after a further week.

After a further 3 weeks, that is to say a total of 5 months after production of the plates, the poisonous effect on houseflies was determined as in Example 4. The results are summarized in the following table: Plate with varnish over time to kill ° of 95% flying in minutes 1 22 2 25 3 16 4 27 5 280 EXAMPLE 6 A pest-killing coating composition is prepared as described under Example 1, but using 6 parts of ethyl mercury thiocyanate as bactericide instead of 24 parts of DDT. Before spraying the mass onto a substrate, 20 parts each. part of a 10% sulfuric acid = butanol solution is added to the mass. This mixture was used to produce a coating and another without any poisonous deposits.

The dry coatings are washed with water and dried again. Cotton flour is dusted on it, which is known to contain various types of bacteria is infected, easily via the coating with the bactericide and also via the coating without bactericide. The plates were then covered with petri dishes and left in an atmosphere constant temperature (25 ° C) and constant relative humidity (70%) 48 hours. long-kept. After this time the dust became. on. separate -Trays with-nutrient-solution-poured and at the same temperature. And humidity cultivated: after 24 hours showed the agar with that of the bactericidal coating only a few small isolated colonies of bacteria, while the control agar showed dense and uniform infestation of bacteria.

Claims (1)

PATENT CLAIM: Process for coating surfaces with a solvent-based paint containing a pesticide, characterized in that an acidic hardener is added to a paint with a butylated urea-formaldehyde resin as a binder and an oil-modified alkyd resin as a plasticizer, shortly before the composition is used, the surfaces to be treated are coated with it and then dried at room temperature. Documents considered: German Patent No. 747 724; Austrian Patent No. 124 991; Swiss patents No. 258216, 269097; French Patent No. 906 726; British Patent Nos. 447 753, 587 263, 605 960; U.S. Patent Nos. 2,097,339, 2,472,847; "Farbe und Lack", 1951, pp. 536 to 540; "Paints, varnishes, paints", 1950, pp. 22, 23; Lange, "Chemisch-TechnischeVorschriften", 1923, p. 662; Roempp, "Chemie-Lexikon", 1949/50, p.369; "Negotiations of the German zoologists in Kiel 1948", Akademische Verlagsgesellschaft Geest & Portig K.-G., Leipzig, pp. 183 to 188 (reprint); CIBA leaflets for paint resin H 53 and M 96.