DE3432998A1 - Paints having a low emission capacity in the spectral region of heat radiation - Google Patents

Abstract

A paint which has a reduced emission capacity in the spectral region of heat radiation and has various colour properties and optionally contains metal particles of high electroconductivity contains, for colouring, only at least one dye which has no perceived colour and/or is transparent and whose coloured pigments are dissolved, and the coloured pigments have a particle size of such dimensions that their scattering and absorbing effect in the spectral region of heat radiation is small. The paint can be used to produce surfaces having a low emission capacity in the spectral region of heat radiation and various colour properties.

Description

Coating materials with low emission sites are able to operate in the spectral range of thermal radiation

description

The invention relates to paints that have a low emissivity in the spectral range of the

Have thermal radiation and different color properties, the paints optionally May contain metal particles of high electrical conductivity.

To avoid energy loss through heat radiation or to reduce it, it is often desirable to make a surface so that it is a low one Has heat emissivity. Such energy losses through heat radiation occur with war-

men pipelines or on walls behind radiators. These energy losses can be seen in to a great extent if the surfaces of such pipelines are formed in such a way that

there is a low heat emissivity. 35

Heat radiation losses in radiators can be countered by placing them behind the radiators reflective surfaces are arranged. Paints with specially adjusted emissivity can also be used for objects e.g. to mark for detection with an infrared search device. Low emissivity paints for thermal radiation are used in military camouflage procedures against infrared reconnaissance used.

Known paints essentially consist of binders and solvents, pigments and various additives. The color of these paints is determined in the visible spectral range by the pigment composition. In the infrared spectral range, in particular in the area of heat radiation at wavelengths between about 2.0 micrometers and about 30 μπι, the optical properties of the paint are dagegegen ² ^ materials substantially by the binder properties determined. This type of paint has a high emissivity for infrared radiation.

It is known (DE-OS 31 18 256) to reduce the emissivity for thermal radiation in that up to 70% by weight of metal pigments of high electrical conductivity are added. If several different Color properties are to be preserved, it is

SQ necessary to add color pigments, since only gray and olive shades can be obtained through the exclusive use of metal pigments. In the examples given in DE-OS 31 18 256, carbon black pigments or color pigments in the color RAL 6015 are mixed in.

Since these color pigments, like all pigments, have a strong absorbing effect in the thermal infrared range, must be the strong absorption of the pigments by high

percentage of metal pigments balanced 5

will. It is also necessary to use binders 2u which have a very high infrared transmission. Dark colors with very low heat emissivity cannot be produced in this way, because the high proportion of metal pigments in the

The visual optical area brightens the color or gives it a metallic appearance.

The invention is based on the object of specifying paints with which surfaces are produced can be that have a low emissivity in the spectral range of thermal radiation and different Have color properties.

According to the invention, this object is achieved by

Character of claims 1 and 2 specified features solved.

The expression "incorporeal dyes" is understood here to mean those dyes which

- Can be dissolved in the solvent of the paint and / or

- can be dissolved in the binder of the paint itself or

- can be in colloidal form, or

- in dissolved form in a powdery binder -

can lie.

All these measures lead to a particle size of the color particles or the color pigments that is in the molecular range lies, whereby with the specific absorption in the spectral range of the thermal radiation only low losses due to scattering or reflection occur.

The advantage here is that, compared to the usual pigment dyes, which are present as larger particles, a significantly lower dye concentration is necessary in order to obtain a desired color. With such bodiless dyes with commercially available binders, which have good transmission in the spectral range of thermal radiation, especially in the spectral range of 3-5 and 8-1 H μΐη, any desired, even dark colors can be produced for the visible spectral range, which have the disadvantages of normal

pigmented colors, namely in the thermal infrared 90

^ ^u strongly absorb, do not have.

Such soluble dyes are advantageous used that have high UV resistance to prevent color change or fading due to exposure to sunlight to avoid. It is also possible, as is provided in the context of the invention, the harmful To counteract the influence of solar radiation that the paint has at least one additional Substance is added that absorbs or reflects in the UV range.

In the context of the invention, preferred binders are those which have a high transmission in the spectral range of the Have thermal radiation, such as cyclo-rubber and chlorine-rubber. Should also have good persistence

against e.g. oil, gasoline and chemicals, binders are preferred in the context of the invention which from polyurethane, PVC copolymers, polyurethane, Polyethylene / vinyl acetate copolymers, hydrocarbon resins, butyl rubber and silicone alkyd resins comprehensive group. Depending on the requirements, you can aqueous binders such as polyurethane / polyacrylate can also be used.

It has been found to be particularly advantageous that when the paints according to the invention are metal particles contain, these formed as metallized hollow microspheres or metallized plastic flakes which are preferably a different particle size with maximum dimensions between 5 and 500 µm exhibit.

In the method according to the invention for producing a

ner surface with low emissivity in the spectral range of thermal radiation and in different A distinction must be made between color properties and whether the carrier, which is to receive such a surface, is itself already a low emissivity in the spectral range of the

Has thermal radiation or not. In the former case, when carrying out the procedure in accordance with Claim 10 the already existing, low emissivity in the spectral range of thermal radiation almost hardly affected. It gets special on it

pointed out that such a low emissivity in the spectral range of thermal radiation is not only in the case of metallic surfaces, but also, for example, by means of a polished graphite foil, as described in the

Invention is provided, can be caused. 35

Surfaces with low emissivity in the spectral range of thermal radiation can be. by Foils with low emissivity, due to substrates to be applied, the metallized hollow microspheres or containing metallized plastic flakes or metal particles. Used with such surfaces If the method according to claim 10 is applied, then overall surfaces are obtained with low Emissivity in the spectral range of thermal radiation and in different color properties. There the applied layer containing the dyes has no significant absorption in the spectral range of the Has thermal radiation, especially when a binder with high transmittance for thermal radiation is used, this layer can be applied relatively thick, so that a great resistance to mechanical stress is achieved. According to the invention, the surface that is already a has low emissivity in the spectral range of thermal radiation, sandblasted or similar roughened metallic surface or also a metal grid or mesh or a metal interwoven Be fabric. According to the invention, the paint can be used as surfaces, depending on the requirements different sizes and different emissivities can be applied.

When a surface with low emissivity in the spectral range of thermal radiation and in different Color property is to be produced, with any carrier, in particular a carrier, whose surface does not have a low emissivity in the spectral range of thermal radiation, so is according to the invention to use the method according to claim 9. The in this case in the paint

Retaining metal particles give the applied paint layer has a low emissivity in the spectral range of thermal radiation. This through the

_ The effect caused by metal particles is ο

In the context of the invention provided dyes for achieving a desired color not or substantially not affected. In this case, too, the paint can be used as surfaces within the scope of the invention different sizes and different emissivities can be applied.

The following examples serve to explain the subjects of the invention in more detail, but without them

to restrict.
15th

example 1

A paint was produced which contained 20% by weight

Zapon dyes dissolved in ethyl glycol and 80% by weight of 20

Contained one-component polyurethane paint. Green Zapon dyes from BASF were used.

The paint was applied to the metal parts of a vehicle applied, the metal parts through sand-25

radiate roughened goods., so that a metallic sheen Surface emerged.

The infrared emissivity in the spectral ranges 3-5 and 8-14 μΐη was 0.4 and 0.55, respectively. Through the 30th

roughened, sandblasted surface, direct reflections from the cold sky or the sun were avoided. This surface acted like a Lambertian radiator, there. the paint applied over it

layer in the thermal infrared range transparent 35

was.

τ * - ■ ■ ■■■■■■

For comparison, a metal surface treated in the same way was compared with a normal, pigmented one Coated paint. The infrared emissivity was greater than 0.8 because of the effect of the metal layer was largely canceled out by the absorption of the color pigments.

Example 2
10

A PVC film was given a metal paint, which consisted of metallized hollow microspheres of different sizes, which were largely in the infrared permeable PVC varnish were dispersed. The diameter

ser of the hollow microspheres was in the range of 6-50 μΐη.

On top of this first layer of metal paint, a second layer of paint was applied, consisting largely of a infrared-permeable PVC varnish, which was coated with brown,

transparent dyes from Hoechst AG.

The infrared emissivity of the PVC film treated in this way was in the spectral ranges 3-5 and 8-14 μm

at 0.35 and 0.45, respectively.
25th

Similar to Example 1, the first metal paint or primer paint worked through the second disembodied dyes through which the layer of paint is colored and which is essentially transparent in the infrared.

The use of hollow microspheres of different diameters in the first coat of paint had to As a result, this first coat of paint acted like a Lambertian radiator or reflector, i.e., radiation and reflection were scattered.

The same experiment was carried out with the modification that instead of the metallized hollow microsphere

Aluminum pigments with an average part-5

particle size of 30 pm were used. The results were comparable to those obtained with hollow microspheres.

Example 3

A paint was produced in which metallized plastic flakes with a size between 10 and 40 µm dispersed in an infrared permeable binder which were made dark with disembodied dyes

was colored green. In this experiment, a butyl rubber varnish with soluble Zapon dyes was used colored. The mixing ratio of butyl rubber to Zapon dyes dissolved in dichloromethane was 70 to 30 wt%. The metal content in the

The coating material was 10% by volume.

The paint thus prepared was applied to a canvas. The infrared emissivity was in the spectral ranges from 3 to 5 and 8 to 14 pm 25

0.4 and 0.45, respectively.

Example 4

On a mosquito screen made of bare metal, an

Coating material applied, which consists of a largely infrared-permeable Binder and a disembodied brown dye. Polyurethane was used as the binder used, which was colored brown with a soluble Zapon dye from BASF. The painting

material consisted of 70 wt .-% one-component polyurethane

-10-

Lacquer and 30% by weight of brown Zapon dye dissolved in ethyl glycol.

The infrared emissivity of the insect screen treated in this way was in the spectral range of 3-5 μm 0.45 and in the spectral range from 8 - 14 μΐη 0.65, since the Binder is less transparent to infrared radiation in this area.

Beis piel 5

Paints with the coloring green, brown and black were arranged irregularly next to each other Stains on a sandblasted metal 15

plate applied. The paints consisted of

a one-component polyurethane paint in which each the soluble Zapon dyes green, brown and black were incorporated. The Zapon dyes were in ethyl glycol dissolved and there were 20 wt .-% of this solution 20

and 80 wt .-% polyurethane paint used. The color black was created from the dissolved Zapon dyes Shown in yellow, blue and red.

The infrared emissivity was in the spectral range 25

from 3 - 5 µm for the colors green, brown and black at 0.45, 0.5 and 0.6, respectively. The infrared emissivity of these colors was in the spectral range of 8-14 µm a little higher, because the polyurethane paint is used in this area

has a poorer infrared transmission. The 30th

Infrared emissivities for green, brown and black were found to be 0.55, 0.65 and 0.75, respectively.

Example 6

A green paint was applied to a rigid polyurethane foam board, which consists of an infrared

-11-

casual binder made of butyl rubber and green in dichloromethane dissolved Zapon dyes and in the metallized hollow microspheres with an average Diameter of 20 μm were dispersed. The mixing ratio of butyl rubber to the dissolved Dyes were 80 to 20% by weight. The proportion of aluminum pigments was 5% by volume of the total paint.

The infrared emissivity of the surface treated in this way was 0.45 in the spectral range from 3 to 5 μm and in the spectral range from 8 - 14 μΐη at 0.55. Additionally the infrared emissivity also became the

, _ Radar transmission measured at 10 GHz. It happened Ib

attenuation of the radar signal below 1 db. Example 7

A paint was applied to a polished graphite sheet 20th

applied, which consisted of a one-component polyurethane paint and dissolved Zapon dyes of the color green. The mixing ratio of one-component polyurethane varnish to Zapon dyes dissolved in ethyl glycol was 80 to 20 wt%.

The infrared emissivity was in the spectral ranges from 3 - 5 µm and from 8 - 14 μΐη to 0.45 or 0.6 measured.

Beis piel 8

On a commercially available insulating wallpaper coated with aluminum, as is to be avoided in residential construction

from heat loss is used, a paint-35

applied material, which consisted of a mixed polyurethane varnish, which with dissolved Zapon dyes brown

- 12-

was colored. The mixing ratio of mixed polyurethane varnish to Zapon dyes dissolved in ethyl glycol was 80 to 20 wt .-%.

The infrared emissivity resulted in the spectral ranges from 3-5 and from 8-14 μπι 0.4 or 0.5.

Example 9

In an aqueous binder made of polyurethane / polyacrylate, which was colored green with water-soluble dyes, became 10% by volume of metallized plastic flakes dispersed. This paint thus prepared was applied to a limestone wall.

The infrared emissivity of the surface treated in this way the limestone wall was 0.5. The infrared emissivity of the rest of the surface on which a

normal, green color pigments containing paint-20

substance was applied, was 0.85.

Due to the invention it is possible to use paints produce that have a low emissivity in

Spectral range of thermal radiation and differed-25

have borrowed color properties. It. Depends on the type of colorants used and the type

tides used binders on whether the dyes

must first be dissolved in a solvent,

to then be mixed with the binder, above whether 30

the dyes can be dissolved directly in the binder. These two possibilities are also under the Invention provided. The paints according to the invention are also provided within the scope of the invention and those after the. method according to the invention

Asked surfaces to apply for infrared camouflage purposes.

Claims (15)

GRÜNECKER, KlNKELDEY. STOCKMAlR & PARTNHB ■: "PATENTANWÄLTE, A GRUNECKER DiU ₁ , κ, ο DR- H. KINKELDEY D.c ..jg DR: W STOCKMAIR. D.-1. ·. » »F ε κ ftc- DR K SCHUMANN dp. pm.s R H JAKOB. Γ f. .Ng DR. G. BEZOLD V. «· W. MEISTER, dp 'νγ, H. HILSERS. d.p * ing DR H. MEYER-PLATH. d.pl ixo DR. M. BOTT-BODENHAUSEN.-D.st pkvs DR. U KlNKELDEY. = 'p- -b.ol • LtCENOe EN DRO ~ OE L UN'V DE GENEVE 8000 MUNICH 22 MAXlMlLlANSTRASSg Se HUGO, Gerd PH 20002-06 / sb Wiesenweg 4 September 7, 1984 Schondorf a.A. P ate η ta η s ρ rü che ^ύΚί 1. Paint which has a low emissivity in the spectral range of thermal radiation and different color properties and which contains metal particles of high electrical conductivity, characterized in that the paint for coloring contains only at least one disembodied and / or transparent dye, the color pigments of which are dissolved, and that the color pigments have a particle size with dimensions such that their scattering and absorbing effect in the spectral range of thermal radiation is small. 2. Paint that has a low emissivity in the spectral range of thermal radiation and has different color properties, thereby -Z- : ■: 3A32998 characterized in that the paint for coloring only at least one disembodied and / or transparent dye ent-5 holds whose color pigments have a particle size with dimensions such that their scattering and absorbing effect in the spectral range of thermal radiation is small, 3. Paint according to claim 1 or 2, characterized characterized in that the at least one dissolved dye is dispersed in a binder is, which has a high transmission in the spectral range the thermal radiation, preferably in the spectral range 15 of 3-5 and 8-14 μΐη. 4. Paint according to claim 1 or 2, characterized characterized in that the at least one dissolved dye is dispersed in a binder is made of PVC copolymers, polyurethane, Polyethylene / vinyl acetate copolymers, hydrocarbon resins, Butyl rubber and silicone-alkyd resins and aqueous binders are selected is. 25th 5. A paint according to claim 4, characterized in that that the aqueous binder is polyurethane / polyacrylate. 6. piercing material according to any one of claims 1 to 5, characterized in that the paint has at least one additional substance which absorbs in the near UV range and reflected. 35 _3_ ■ ..- ";" . ■ Ζ "3Λ32998 7. A paint according to claim 1, characterized in that that the metal particles contained in the paint have a different particle size have, preferably with dimensions of 6 - 50 μΐη. 8. A paint according to claim 1, characterized in that g e, Q indicates that the metal particles contained in the claim material are metalized hollow microbeads or metallized plastic flakes are, which are preferably a different particle size with dimensions between 5 and have μΐη. 9. Process for producing a surface with low emissivity in the spectral range the thermal radiation and in different color "" Properties, characterized that a paint according to claim 1 or according to claim 1 in combination with at least one of Claims 3 to 8 is applied to a carrier. "P. 10. A method for producing a surface with low emissivity in the spectral range of thermal radiation -, and in different color properties, characterized in that a paint according to claim 2 or according to -. Claim 2 in combination with at least one of claims 3 to 6 is applied to a surface which has a low emissivity in the spectral range of thermal radiation. 11. The method according to claim 10, characterized in that that the surface with -U- low emissivity in the spectral range of thermal radiation a sand-blasted or similar roughened metallic surface. 12. The method according to claim 10, characterized in that that the low emissivity in the spectral range of the heat _. radiation exhibiting a metal-containing surface Primer is. 13. The method according to claim 12, characterized in that that as metalliferous ._ primer a primer is used. Io the metallized hollow microsphere or metallized plastic flakes, preferably with different Particle size between 5 and 500 μπι contains. 14. The method according to claim 10, characterized in that indicates that the low emissivity in the spectral range of thermal radiation having surface a metal grid or mesh or a metal woven fabric is. 15. The method according to claim 9 or 10, characterized in that the paint as areas of different sizes and different emissivities in the spectral range of thermal radiation is applied.