EP1429104B1 - Heat camouflage covering - Google Patents

Abstract

The camouflage tarpaulin, which also prevents the escape of heat which could be detected by a thermal imager, has a textile carrier (1) of glass filaments in a woven or knitted or warp knitted structure with polyester bonding filaments, in a fabric weight of 400 g/m2. The camouflage tarpaulin, which also prevents the escape of heat which could be detected by a thermal imager, has a textile carrier (1) of glass filaments in a woven or knitted or warp knitted structure with polyester bonding filaments, in a fabric weight of 400 g/m2. The outer surface has a polyurethane coating (4) containing color pigments (5), preferably metal pigments containing chrome oxide. The under side of the carrier has a silicon and/or polyurethane coating (6) containing aluminum powder (7).

Description

The invention relates to a heat tarpaulin according to the preamble of claim 1.

A generic Wärmarnplane is from the DE 297 16 362 known.

For military camouflage of fixed and mobile military equipment, such as motor vehicles, tanks and the like, camouflage nets are used. The camouflage nets should generate not only a camouflage in front of infrared cameras or thermal imaging detectors, but also before radar detection. The camouflage net is intended to prevent microwaves impinging on an object from being reflected back by it. Furthermore, it should be prevented that an identification by sensors in the infrared or thermal imaging is possible. For this purpose, a camouflage net in a certain material composition has a suitably adapted hole structure of the net to provide both visible and near infrared protection, good damping values to generate a broad spectrum of the microwave range and to be low imitating in the thermal image area (see eg DE 40 23 287 C2 ). Such camouflage nets generally serve their purpose. Camouflage becomes problematic, however, if a hot spot is present locally under the camouflage net, eg by the engine of a vehicle or else by a stationary engine. Due to the network structure, this local hot spot can be located in the infrared range, eg in the far infrared range.

In order to avoid this detection, tarpaulins are already known from practice, with which the hot spot is covered. However, the known tarpaulins have various disadvantages, such as e.g. poor mechanical strength and a limited temperature range with the risk of combustion at too high a temperature. This means a limited handling for the rough practice operation.

The generic document describes a Wärmarnplane to cover heat sources, which has significant improvements in terms of the above-mentioned prior art. The generic heat tarpaulin has on the side facing the object to be covered a coating with a silicone elastomer containing aluminum powder on. The other side is provided with a silicone elastomer containing metal pigments whose reflectance values are within the range of visual-optical camouflage. As a result, the heat tarpaulin is within a wide temperature range effective, at the same time given an improved mechanical strength and a high temperature resistance.

However, in the further development of the generic heat tarpaulin it has been found that, despite the improved mechanical strength due to buckling, fiber breakage and destruction of the coating can already occur at a relatively early point in time. This is especially true in an embodiment of the generic Wärmarnplane based on warp knitted fabric. In experiments, it has also been found that the generic Wärmarnplane has damage during storage for a long time at the kinks or they are destroyed. A further disadvantage of the silicone elastomer-based heat tarpaulin is that the color design is limited in the visible range as well as in the near infrared (650 to 1250 nm). In addition, the surface of the heat tarpaulin coated by the silicone elastomer shines, thereby increasing the risk of detection. A disadvantage is also that can not be adhered to the silicone elastomer coated surface of the heat tarpaulin article numbers.

With regard to the reflection of the side of the heat tarpaulin facing the object to be covered which has a silicone elastomer coating provided with aluminum powder, an improvement is also desirable.

The present invention is therefore an object of the invention to solve the above-mentioned disadvantages of the prior art, in particular to further improve the generic Wärmarnplane, so that the usefulness and storability of the Wärmarnplane is increased, as far as possible all occurring in nature colors are modeled can be achieved, largely values in the infrared corresponding to those of nature, as well as a matte surface is achievable.

According to the invention this object is achieved by the characterizing part of claim 1.

By virtue of the fact that the coating comprising color pigments, ie the colored side of the heat tarpaulin facing away from the object to be covered, has a polyurethane coating (or polyurethane elastomers) or a polyvinylidene fluoride coating (or polyvinylidene fluoride), all the colors occurring in nature can be used Reproduce. The generic Wärmarnplane could be generated due to the silicone elastomer coating only in a very limited color palette. Now it is possible, in addition to the usual green optics, which was used especially for use under Woodland camouflage nets, also one of the desert (sand color) or one of the Arctic (white) adapted to realize optics.

Experiments have shown that the polyvinylidene coating can achieve refelion values which are significantly higher than those of the polyurethane coating.

With the polyurethane coating according to the invention or the polyvinylidene fluoride coating (PVDF) of the heat tarpaulin, it is possible to produce values in the infrared range that correspond to those of nature.

In a particularly advantageous manner, it is possible by the polyurethane coating or the Polyvinylidenfluoridbeschichtung to produce a matte surface, whereby the detectability is reduced.

As has been shown in experiments, it is easily possible to apply article numbers to the polyurethane coating or the polyvinylidene fluoride coating.

In the comparison of the reflectometer values of the generic heat tarpaulin, which were at 60 ° at 2.8 and at 85 ° at 1.4, resulting in the new based on the polyurethane coating or the Polyvinylidenfluoridbeschichtung inventive heat tarpaulin values at 60 ° at 2.2 and at 85 ° at 1.6. It is essential that, although the difference based on the values is not so clear, but clearly noticeable in a visual comparison of the generic Wärmarnplane with the new Wärmarnplane invention, that the generic Wärmarnplane shines stronger and is thus easier to discover.

The heat tarpaulin according to the invention is incombustible. This means that it can be safely placed directly on hot spots.

It is advantageous if the carrier textile is formed as a glass filament fabric, preferably as a cross twill.

In experiments it has been found that the heat tarpaulin provided with the polyurethane coating or the Polyvinylidenfluoridbeschichtung by a design as a woven fabric based on cross twill, preferably cross twill 01 02, a particularly high kink resistance. In particular, when stored for a long time and when using the Wärmarnplane can thereby significantly extend the life of the Wärmarnplane. In comparison with the generic heat tarpaulin, which was preferably formed on the basis warp knitted fabric, there is a fivefold of the usability and storability.

It is also advantageous that in addition to the increase in kink resistance also results in an increase in strength. The generic heat tarpaulin based warp knitted fabric had a, compared to the other prior art, already increased strength of 1,900 N / 5 cm in the warp and weft directions. The invention Wärmarnplane based Kreuzköper 01 02 has a strength of 4,000 N / 5 cm in the warp and 3,000 N / 5 cm in the weft.

According to the invention it can be provided that the coating containing aluminum powder is formed as a silicone elastomer coating and / or as a polyurethane coating.

The aluminum powder in combination with the silicone elastomers and / or the polyurethane ensures a correspondingly high heat radiation, while on the other hand, the polyurethane or the polyvinylidene fluoride in conjunction with the color pigments ensures a reduction in recognition in the visible and in the infrared range. The color pigments and the polyurethane coating or the Polyvinylidenfluoridbeschichtung can be achieved a surface color design that is adapted to the environment and / or a camouflage net lying above.

It is advantageous if the coating containing aluminum powder and / or the color pigments is applied by means of a transfer coating method.

The advantage of the transfer coating process is that it does not directly coat the glass fibers. This results in a softer, more flexible material which is less susceptible to cracking. The surface becomes smoother as it is applied only superficially, yet the entire glass fiber is covered. In contrast to the principle also possible Direct coating creates no "valleys and heights" through the tissue.

When coating the aluminized side, it has been found that a coating application by means of a transfer process increases the IR activity of the aluminum side by a multiple. Due to this increase in activity, it is possible to achieve a reflection of 80 to 100% in the solar range (from 0.4 μm to 4 μm). In the upper thermal range (from 4 μm to 13 μm) values over 50% are achieved.

In experiments, it has been found that the aluminum parts are much better oriented by application by means of the transfer coating process than by application by means of a direct coating method. This results in a particularly smooth surface.

It has proven to be advantageous if the aluminum layer has an optical density of 2.9 to 3.5%. It has also proved to be advantageous if the coating of the aluminum side has a weight of 40 to 50 g / m ² .

In one embodiment of the invention can be provided that the carrier fabric is formed of warp knit fabric, wherein each a glass filament performing warp and a weft thread are bound to each other by means of a plastic thread system.

Depending on the application, the warp knitted fabric can be designed so that the strength of fabric or a desired elasticity is achieved, with greater elasticity breaking the Trägertextilie and thus wear of the heat tarpaulin is reduced.

By means of a large range of vibration of chain extensions and / or crosslinks of the prepolymer, the end property of the polyurethane elastomers can be tailored. If silicone elastomers are used instead of the polyurethane on the side provided with the aluminum powder, these may also be crosslinkable.

Very good values with regard to heat reverberation have resulted in a proportion of 15 to 40 percent by weight of aluminum powder in the polyurethane or silicone elastomer on the side of the heat tarpaulin facing the object to be covered, wherein the proportion in a glass filament fabric is preferably 30 percent by weight and in the case of one Warp knitted carrier fabric is 20 to 40 weight percent.

The color pigments admixed to the polyurethane or polyvinylidene fluoride on the other side should advantageously be selected such that 10 to 50% of color pigments, preferably 30% of color pigments, are contained on the outside in the polyurethane or polyvinylidene fluoride. Due to the color pigments and the polyurethane coating or the Polyvinylidenfluoridbeschichtung All colors occurring in nature can be reshaped in terms of appearance.

It is advantageous if color pigments are present in the polyurethane or polyvinylidene fluoride, whose remission values are in the range light green to dark green, for which the color pigments may have metal pigments which preferably contain chromium oxides, which have been found to be particularly suitable.

In order to achieve sufficient stability or strength, it is advantageous to use a carrier textile which has a weight per unit area of 300 to 450 g / m ² , preferably 400 g / m ² .

As basis weight values for the polyurethane to be applied on both sides (if provided on both sides), 30 to 90 g / m ² per side have been found to be most suitable, preferably the coating should have a weight of 70 to 80 g / m ² ,

In a further development of the invention, it may further be provided that the edges of the heat tarpaulin are sealed with cold-crosslinking polyurethane. The heat tarpaulin invention is made up in a prescribed size. Here, the heat tarpaulin is cut conventionally. By sealing the heat tarpaulin after cutting with a kaltvernetzendem polyurethane fraying the heat tarpaulin is prevented. In a particularly advantageous manner, this avoids frayed light spots of the coating containing aluminum powder or uncoated areas of the inside of the fiber from escaping to the outside and thus adversely affecting discoverability.

Further advantageous embodiments of the invention will become apparent from the other dependent claims and from the embodiments illustrated in principle below with reference to the drawing.

Fig. 1

eine äußerst schematisierte Zusammensetzung einer erfindungsgemäßen Wärmetarnplane im Querschnitt stark vergrößert;

Fig. 2

eine Darstellung einer Bindungspatrone eines Kreuzköpers 01 02; und

Fig. 3

eine Draufsicht auf eine als Kettengewirke ausgebildete Trägertextilie.

It shows:

Fig. 1

a highly schematic composition of a Wärmarnplane invention greatly enlarged in cross-section;

Fig. 2

a representation of a binding cartridge of a Kreuzköpers 01 02; and

Fig. 3

a plan view of a trained as warp knitted carrier fabric.

Wärmarnplanen are already well known in terms of their purpose and in terms of their basic structure as knitted or warp knitted fabric and as a fabric, including on the DE 297 16 362 Reference is made, therefore, only the essential features of the invention will be described in more detail below.

In the embodiment according to Fig. 1 is based on the heat tarpaulin a carrier textile 1, which is formed as a glass filament fabric in a twill weave, preferably as a cross twill with a basis weight of 400 g / m ² is used.

Fig. 2 In this case, the vertical columns of the binding cartridge shown represent the warp threads 2, the horizontal rows of weft threads 3. When the warp thread 2 is on the surface, which is in Fig. 2 filled field of the binding cartridge filled when the weft yarn 3 is on top, the field is empty.

In the Fig. 1 illustrated carrier fabric 1 has on the side facing away from the object to be covered, namely the outside, which is directed upward, a polyurethane coating 4. Preferably, the outside is provided with the polyurethane coating 4 in the direct coating process or transfer coating process. The polyurethane coating 4 is a proportion of 10 to 50% of color pigments 5, preferably 30% of color pigments 5, admixed. The color pigments 5 in this case have metal pigments, not shown, which may contain chromium oxides. The polyurethane coating 4 may, for example, have a basis weight of 30 to 90 g / m ² .

To realize particularly good reflection values, it is also possible to provide a polyvinylidene coating instead of the polyurethane coating 4. This is preferably applied by the transfer coating method. The values and embodiments given in the exemplary embodiment apply identically also to the polyvinylidene coating.

A formation of the metal pigments as chromium oxides is particularly advantageous if good remission values in the range from light green to dark green and thus camouflage in the visible and in the near infrared should be achieved.

The remission values may be dark green color e.g. at 400 nm 8, at 550 nm 10, at 600 nm 8, at 650 nm 8, at 750 nm 37, at 800 nm 46, at 1200 nm 44 and at 1800 nm 44. The large increase at 750 nm is called chlorophyll jump and is modeled on the behavior of deciduous trees in this wave range.

In the Fig. 1 illustrated carrier fabric 1 is also coated on the object to be covered facing side with a polyurethane coating 6, the 15 to 40 weight percent aluminum powder 7 is mixed. The polyurethane coating 6 can also be applied by direct coating. For this purpose, a crosslinkable polyurethane coating 6 is particularly suitable. Analogously, the polyurethane coating 4 may be formed as a crosslinkable polyurethane coating.

The polyurethane coating 6 provided with the aluminum powder 7 may, in an alternative embodiment, also be embodied as a silicone elastomer coating provided with aluminum powder 7, since on this side of the carrier textile 1 the reflectance alone is significant.

The reflection values of the heat tarpaulin according to the invention are in the range of 0.4 to 2.5 nm over 50%.

The silicone elastomer used instead of the polyurethane coating 6 can also be applied by direct coating and be formed as a crosslinkable silicone elastomer.

As the crosslinker, a hydrogenpolysiloxane having a high content of reactive Si-H can be used. 2% by weight are mixed with the silicone elastomer.

After painting, the vulcanization should be heated to approx. 150 ° for a period of three minutes. The vulcanization time depends on the temperature used. This means that at higher temperatures results in a lower vulcanization time and vice versa.

The heat tarpaulin can be exposed to a temperature range of more than 1,000 ° C for several minutes without damaging it, resulting in the heat tarpaulin is practically incombustible. As an alternative to the in Fig. 1 and Fig. 2 formed as a glass filament fabric carrier textile is in Fig. 3 an embodiment of the carrier textile 1 shown as warp knit.

The support textile 1 produced on a Raschel machine with weft insertion, designed as warp knitted fabric, has warp threads 2 made of glass fibers and weft threads 3 made of glass fiber or glass filament, which do not act as in the embodiment of the support textile according to FIG Fig. 1 are guided over and under each other, but lie one above the other and are bound together by an elastic plastic thread system 8, which is a polyester Abbindefaden.

The advantages according to the invention can also be represented essentially as a warp knitted fabric by an embodiment of the support textile 1. In experiments, it has been found, however, that an embodiment of the carrier textile 1 as a glass filament fabric or as a fabric preferably according to the in Fig. 2 illustrated cross twill weave is particularly suitable.

Claims (16)

1. A thermal camouflage sheet for covering heat sources against identification in a thermal image, having a base textile with a glass filament, which on one side has a coating containing aluminum powder and on the other side has a coating containing color pigments, with the remission values of the color pigments being in the range of visual-optical camouflage,
   wherein
   at least the coating containing color pigments (5) is in the form of a polyurethane coating (4) or a polyvinylidene fluoride coating (PVDF).
2. The thermal camouflage sheet as claimed in claim 1,
   wherein
   the coating containing aluminum powder (7) is in the form of a silicone elastomer coating and/or a polyurethane coating (6).
3. The thermal camouflage sheet as claimed in claim 1 or 2,
   wherein
   the base textile (1) is in the form of a glass filament fabric.
4. The thermal camouflage sheet as claimed in claim 3,
   wherein
   the glass filament fabric (1) is in the form of a twill binding, preferably a cross-twill.
5. The thermal camouflage sheet as claimed in claim 1 or 2,
   wherein
   the base textile (1) is in the form of a warp knit, with a warp thread (2) which in each case represents a, glass filament and a weft thread (3) being linked to one another by means of a plastic thread system (8).
6. The thermal camouflage sheet as claimed in claim 5,
   wherein
   the plastic thread system (8) represents a binding thread composed of polyester.
7. The thermal camouflage sheet as claimed in one of claims 1 to 6,
   wherein
   the color pigments (5) contain metal pigments.
8. The thermal camouflage sheet as claimed in claim 7,
   wherein
   the metal pigments contain chromium oxide for green color tones.
9. The thermal camouflage sheet as claimed in one of claims 1 to 8,
   wherein
   the polyurethane (4, 6) is a polyurethane which can be crosslinked.
10. The thermal camouflage sheet as claimed in claim 9,
    wherein
    urea and/or urethane are/is provided for crosslinking of the polyurethane (4, 6).
11. The thermal camouflage sheet as claimed in one of claims 1 to 10,
    wherein
    the edges of the thermal camouflage sheet are sealed with cold-crosslinked polyurethane.
12. The thermal camouflage sheet as claimed in one of claims 1 to 11,
    wherein
    the proportion of aluminum powder (7) in the polyurethane (6) on the side facing the object to be covered is 20 to 40% by weight.
13. The thermal camouflage sheet as claimed in one of claims 1 to 12,
    wherein,
    on the outside, the polyurethane (4) contains 10 to 50% color pigments, preferably 30% color pigments (5).
14. The thermal camouflage sheet as claimed in one of claims 1 to 13,
    wherein
    the polyurethane contains color pigments (5) whose remission values are in the range from bright green to dark green.
15. The thermal camouflage sheet as claimed in one of claims 1 to 14,
    wherein
    the base textile (1) has a weight per unit area of 300 to 450 g/m², preferably 400 g/m².
16. The thermal camouflage sheet as claimed in one of claims 1 to 15,
    wherein
    the coating (4) which contains aluminum powder (7) and/or color pigments (5) is applied by means of a transfer coating method.

Images