DE977737C - Infrared camouflage paint - Google Patents

Description

. For infrared camouflage paints, it has recently been required that the infrared reflection curve of this and inevitably that of the Pigments in the wavelength range which is outside the sensitivity of normal image converters i.e. longer than about 1.2 μ in relation to the "leaf green curve" as deep as possible.

A large number of color bodies have already been proposed for camouflage in the infrared, so in particular also chromium oxide green and chromium oxide hydrate green. However, these dyes correspond not today's ideas about a camouflage that meets all requirements, either because they are much brighter than the surrounding area in the area above about 1.2 μ Nature, or because they, like z. B. the chromium oxide green and chromium oxide hydrate green in the area from 0.8 to 1.0 μ not, similar to the reflection of natural leaf green, show a rising increase in their reflectance values. Such pigments can ao therefore only in combination with other pigments, for example to achieve a desired visible color Hues, can be used.

The above requirement, namely a decrease in reflection beyond 1.2 μ, is now in satisfactorily met by aluminum sulfate, also by - as pigments for visible and Infrared camouflage of the previously known type - chromium oxide green and / or chromium oxide hydrate green or manganese dioxide mixed with aluminum sulfate.

The infrared reflection curve of aluminum sulfate is in the range of the image converter sensitivity - i.e. between 0.8 and 1.2μ with a maximum ι μ - initially high and then falling sharply.

909 613/1993

Not only the above-mentioned substances and their mixtures meet the recently set conditions, but also their equipment with pigments, which are reaction products of magnesium, calcium and zinc oxide or hydroxide with soluble chlorides, silicates, sulfates and phosphates, especially those which are Deposits of heavy metals ^: show.

ίο You can achieve a particularly good effect with Aluminum sulfate, the heavy metals (preferably nickel, cobalt, copper, iron, chromium, lead, manganese) incorporated in the crystal lattice, preferably in amounts below 5% (calculated as heavy metal in the end product). The reflection curve of such an aluminum sulfate shows a further decrease in the range of over 1.3 μ compared to the previously known pigments. The following examples bring together

ao tongues of the pigments which are in the desired infrared spectral range for camouflage purposes are effective without further information on the paint binders and paint components to be used for the visible area.

Example 1 45 g of aluminum sulfate in 50 g of alkyd resin.

Example 2

50 g aluminum sulfate + 10 g chromium oxide green in 40 g phenolic resin.

Example 3

55 g aluminum sulfate + 0.5 g manganese dioxide + 14.5 g Chromium oxide hydrate green in 30 g nitro lacquer binder.

Example 4

20 g aluminum sulfate + 5 g chromium oxide green + 15 g of a reaction product of the type described above +5 in 60 g of ketone resin.

Such reaction products can be obtained according to the following recipes:

a) 100 g magnesium oxide + 100 ecm one 10% magnesium chloride solution in water. After the reaction is complete, the resulting reaction body is comminuted as fine as a pigment.

b) 100 g magnesium oxide + 100 ecm one 20% zinc sulphate solution in water +0.5 g copper sulphate.

The resulting reaction product is ground to a fine pigment.

c) 20 ecm of a 30% magnesium chloride solution in water + 50 ecm of soda water glass (d - 1.40) + ig chromium chloride, diluted with 100 ecm of water. The resulting reaction product is filtered off and carefully dried.

d) 100 ecm of a 30% magnesium chloride solution in water + 100 ecm aqueous ammonium sulfate solution (ei = 1.195) +0.8 g manganese chloride. The resulting reaction product is filtered off and dried.

The effect of the pigments or paints according to the invention is shown on the attached diagram sheets explained in more detail.

Fig. Ι now shows the reflection curves of four Pigments, namely curve 1 represents an aluminum sulfate pigment, curve 2 is a pure pigment, as described in examples a), b), c) or d), curve 3 is a 1: 1 mixture of aluminum sulfate with the pigment corresponding to curve 2 and finally curve 4 for a pigment is more similar Production as shown in Example 5, with the only difference that instead of iron Cobalt salt was used. This clearly shows that with all these pigments the increase in the Edge Visible — Infrared is present as desired, and further that curve 4 against the Water hole 1.4 to 1.6 drops considerably and also continues to decrease towards the end of the spectral range (2.5 μ).

If this pigment is now incorporated in suitable, per se known lacquers, a coating such as it is indicated in curve 5, received. If one now looks at the green area in Fig. 2 and the paint reflection curve 5 of Fig. 1, one can clearly see the. already extensive alignment with the Surroundings. The curves are recorded with an IR spectrograph Perkin-Elmer M 21 against freshly evaporated MgO as standard.

Claims (1)

PATENT CLAIM: Paints for camouflage in the wavelength range over 1.2 μ, which in addition to pigments, the by reacting magnesium, calcium and zinc oxide or hydroxide with soluble ones Chlorides, sulfates, silicates and phosphates with possible storage of heavy metals have been produced, possibly manganese dioxide, chromium oxide green and / or or chromium oxide green still contain aluminum sulfate. Considered publications:
French Patent No. 1,033,708;
Paintures, Pigments, Vernis, 1944, April issue, pp. 99 to 110. For this purpose 2 sheets of drawings θ 909 613/1993 3.69