The present invention relates to a flat element comprising a substrate and a coating of the substrate whereby both the substrate and the surface of the flat element are pigmented coloured dark in the visible light range. In the near-infrared range the flat element has high reflection so as to reduce it becoming heated up in sunlight despite the dark pigmentation colour in the visible light range. Such a flat element finds application on all surface areas needing to be pigmented coloured dark for aesthetic or technical reasons but which should not heat up when exposed to sunlight and in cases where the dark colour is maintained even when the coating is damaged.
Surfaces which need to be coloured dark for aesthetic or technical reasons and which are exposed to sunlight have the usual nuisance tendency to become more or less heated up depending on how dense the colouration is.
It is particularly in confined spaces such as e.g. in a vehicle be it an automobile, a truck, a bus or also the interiors of railcars that this solar heating up of dark surface areas is experienced as a real nuisance. The dark surface areas heat up more or less, depending on their degree of solar absorption and give off their heat into the interior of the vehicle. This heat then requires compensating with an air-conditioning system which adds to the energy consumption of the vehicle quite considerably.
In any vehicle there are surface areas which for technical reasons need to be coloured dark. One good example of this is the dashboard top in an automobile. Were it coloured bright it would reflect in the windscreen and prove a nuisance to the driver's view ahead. This is why it naturally needs to be coloured dark. Since this surface area is located directly under the windshield it is exposed the most to solar radiation and heats up accordingly. Apart from the nuisance of this heating up the vehicle, this increase in temperature of dark surfaces also results in accelerated material fatigue of the surface areas involved.
It is more for aesthetic reasons that leather seats in automobiles are mainly coloured dark grey, indeed mostly even black. When this vehicle has been standing in the sun for quite some time with the leather seats exposed to the sunlight, they heat up so much they become almost unbearably hot.
Even more of a nuisance is the heating up of steering wheels in sunlight since they usually need gripping with the bare hand without any cladding.
Proposed in PCT/EP96/04703 is a means for producing coatings reflecting heat radiation. This describes a coating having a higher reflection for sunlight in the near-infrared range. The drawback in this case is that all substances result in higher reflection for sunlight in the near-infrared range need to be incorporated in a single layer.
This has the result that when producing very dark or black tints the reflection for sunlight in the near-infrared range is only slightly higher since the higher the filling with reflective substances the more the reflection increases also in the visible light range.
Another disadvantage is that when the coating is damaged the normal undercoat is exposed having no enhanced sunlight reflection, thus negating the effect at this location.
Were the undercoat coloured white this would restore the enhanced reflection to sunlight but for aesthetic reasons this is not possible since everywhere where the coating becomes damaged or is no longer present the white undercoat would “grin” through.
It is thus the objective of the present invention to provide a substrate which, having the same colouration in the visible light range as the coating thereon, shows a high reflection in the near-infrared range and is provided with a coating which in the visible light range is dark and in the near-infrared range is mainly transparent and/or self-reflective and which with a normal pigment fill also satisfies all mechanical requirements in later application.
In accordance with the invention this is achieved by a flat element having a dark surface and exhibiting a reduced solar absorption comprising
The coating may also be applied to the substrate in a single layer or several thin layers.
“Dark” in the context of the present application is to be understood that the reflection of the system in the wavelength range of visible light from 380 to 720 nm is less than 50%. Reflection in this sense is understood to be the reflection as averaged over the cited wavelength range; the same applying to the terms “transmittance”, “absorption” and “backscatter”.
Advantageous aspects of the gist of the invention read from the sub-claims.
One advantageous aspect of the gist of the invention results from the substrate being a fibrous material selected from the group of plastics, selected from artificial leather, selected from non-wovens or wovens of polyethylene, polypropylene, polyester, nylon and acetates such as cellulose acetate, from the group of natural materials, selected from leather, selected from non-wovens or wovens from sisal, hemp, cellulose, cotton and from silk.
An advantageous aspect of the gist of the invention results from the substrate being a foamed, preferably reactive and/or mechanically foamed material, selected from the group of plastics, selected from polyethylene, polypropylene, polyester, nylon, ABS, epoxy, polyurethane and PVC.
Another advantageous aspect of the gist of the invention results from the substrate being a material selected from the group of plastics, selected from polyethylene, polypropylene, polyester, nylon, ABS, epoxy, polyurethane and PVC and filled with fillers to 40 to 80 volume percent having in the wavelength range 380 to 1500 nm a transparency exceeding 70% and whose particle size is selected so that they have a low backscatter in the visible light range. In accordance with the invention a backscatter is low when it amounts to less than 50% of the incident radiation.
Another advantageous aspect of the gist of the invention results from the substrate being formed after drying from an initially fluid binder filled with fillers to 40 to 80 volume percent having in the wavelength range 380 to 1500 nm a transparency exceeding 70% and whose particle size is selected so that they have a low backscatter in the visible light range.
In accordance with the invention it is preferred that the reflection of the substrate in the visible light range from 380 to 720 nm being less than 50% is caused by colouration with soluble dyes or pigments.
The soluble dyes are preferably water-soluble dyes or dyes soluble in solvents. The group of water-soluble dyes comprises acidic dyes, substantive dyes, basic dyes, developed dyes, sulphuric dyes and aniline dyes; the group of dyes soluble in organic solvents comprises more preferably zapon dyes. The soluble dyes are employed preferably in a quantity of 0.2 to 10% by weight, preferably 2 to 6% by weight relative to the formulation.
Another advantageous aspect of the gist of the invention results from the first pigments which in the visible light range from 380 to 720 nm result in a reduced reflection of the coating less than 50% and in the spectral range of the near-infrared range from 720 to 1500 nm show a reflection exceeding 50% being selected from the group of organic pigments, selected from the group of azo pigments, selected from monoazo, disazo, β-naphthol, naphthol AS, lacquered azo, benzimidazolon, disazo condensation, metal complex, isoindolinon and isoindolin pigments, being selected from the group of polycyclic pigments, selected from phthalocyanine, chinacridon, perylene and perinon, thioindigo, anthraquinone, anthrapyrimidin, flavanthrone, pyranthrone, anthanthrone, dioxazine, triarylcarbonium, chino-phthalone, diketo-pyrrolo-pyrrole pigments. The first pigments are employed preferably in a quantity of 0.2 to 20% by weight, preferably 0.7 to 10% by weight relative to the total formulation for producing the coating.
Yet another advantageous aspect of the gist of the invention results from the second pigments which in the visible light range from 380 to 720 nm result in a reduced reflection of the coating less than 50% and in the spectral range of the near-infrared range from 720 to 1500 nm show a reflection exceeding 40% being selected from the group of inorganic pigments, selected from the group of metal oxides and hydroxides, from cadmium, bismuth, chromium, ultramarine pigments, selected from the group of coated, laminar mica pigments, selected more preferably from the group of rutile and spinelle mixed phase pigments. The second pigments are employed preferably in a quantity of 4 to 50% by weight, preferably 10 to 40% by weight relative to the total formulation for producing the coating.
Yet another advantageous aspect of the gist of the invention results from the fillers being selected from the group of degradable minerals, selected from metal oxides, selected from aluminum oxide, magnesium oxide, quartz, selected from blends of metal oxides, selected from zirconium silicate, clay, selected from metal carbonates, selected from calcium carbonate, selected from metal sulfates, selected from barium sulfate, the average particle size of which is set by grinding to an average of 1 to 3 μm. The fillers are preferably employed in a quantity of 1 to 45% by weight, more preferably 8 to 35% by weight with respect to the formulation.
Still another advantageous aspect of the gist of the invention results from the binder being selected from the group of solvent-based binders comprising acrylates, methacrylates, styrene-acrylates, styrene-methacrylates, selected from substituted polyolefins, selected from polystyrene and styrene copolmers, alkyd resins, selected from saturated and non-saturated polyesters or polyamides, polyimides, polyurethanes, polyethers, epoxy resins, silicones, chlorosulfonated polyethylene, fluorated polymers selected from fluorated acrylic copolymers or fluorosilicones;
selected from the group of aqueous binders comprising the group of aqueous binders from alkyd resins, polyesters, polyacrylates, epoxides and epoxide esters, from the group of aqueous dispersions and emulsions, comprising dispersions and emulsions based on acrylate, methacrylate, styrene acrylate, polyethylene, polyethylene oxidate, ethylene acrylic acid copolymers, methacrylate, vinylpyrrolidone-vinylacetate copolymers, polyvinylpyrrolidone, polyisopropylacrylate, polyurethanes, wax dispersions based on polyethylene, polypropylene, Teflon®, synthetic waxes, fluorated polymers, fluorated acrylic copolymer in aqueous solution, fluorosilicones.
The binders are advantageously employed in a quantity of 20 to 90% by weight, preferably 30 to 80% by weight, relative to the total formulation for producing the coating.
Still another advantageous aspect of the gist of the invention results from the average particle size of the first pigments being smaller than 0.9 μm and the average particle size of the second pigments being greater than or equal to 0.9 μm.
Still another advantageous aspect of the gist of the invention results from the reflection of the substrate in the spectral range 720 to 1500 nm exceeding 70%.
Yet another advantageous aspect of the gist of the invention results from the reflection of the substrate with soluble dyes and/or the coating in the spectral range of visible light from 380 to 720 nm being less than 40%.
Still another advantageous aspect of the gist of the invention results from the first and/or second pigments in the spectral range of visible light from 380 to 720 nm resulting in a low reflection of the coating of the substrate of less than 40%.
Still another advantageous aspect of the gist of the invention results from the mechanical foam being formed by the inclusion of hollow microbeads of glass or plastics.
Yet another advantageous aspect of the gist of the invention results from layer thicknesses of the substrate being in the range 10 μm to 8 mm, more particularly in the range from 20 μm to 6 mm.
Still another advantageous aspect of the gist of the invention results from layer thicknesses of the coating being in the range 10 μm to 500 μm, more particularly in the range from 20 μm to 300 μm.
The subject matter of the invention will now be detailed by way of examples.
The coating was applied wet with a spiral applicator 3×100 μm to the dyed leather and then dried.
A standardized black pre-dyed leather was coated with a black standardized coating. The standardized coating consists of an acrylic-copolymer emulsion and an aqueous polyurethane dispersion formulated as specified for the particular application with commercially available waxes, fillers, casein and oil. For blackening black ferrous oxide, an aqueous pigment dispersion of and an aqueous dispersion of carbon black was added to this binder mixture.
The spectral reflection of the samples was plotted in the range 400 to 980 nm (measuring apparatus: Avantes PC spectrometer module PC 2000 with a spectral sensitivity of 320 to 1100 nm with an Ulbricht sphere for measuring the hemispherical backscatter of surfaces); the plotted results are illustrated in
The plotted results as shown in
The samples were bonded to a panel of expanded polystyrene and measured with a radiation thermometer exposed to 98000 Lx solar radiation.
The black leather coated in accordance with the invention heated up to 54° C.
The black leather in accordance with the comparison example heated up to 67° C.
The coating was applied wet with a spiral applicator 3×100 μm to the leather dyed as per a).
A standardized grey pre-dyed leather was coated with a grey standardized coating. The standardized coating consists of an acrylic-copolymer emulsion and an aqueous polyurethane dispersion formulated as specified for the particular application with commercially available waxes, fillers, casein and oil. For greying an aqueous pigment dispersion of titanium dioxide (rutile), black ferrous oxide and an aqueous dispersion of carbon black was added to this binder mixture.
The spectral reflection of the samples was plotted in the range 400 to 980 nm; the plotted results are illustrated in
The plotted results as shown in
The samples were bonded to a panel of expanded polystyrene and measured with a radiation thermometer exposed to 98000 Lx solar radiation.
The grey leather coated in accordance with the invention heated up to 53.5C. The grey leather in accordance with the comparison example heated up to 64.5° C.
The coating was applied wet with a spiral applicator 3×100 μm to the dyed woven.
A standardized black dyed woven was coated with a black standardized coating. The standardized coating consists of an acrylic-copolymer emulsion and an aqueous polyurethane dispersion. For blackening an aqueous pigment dispersion of black ferrous oxide and an aqueous dispersion of carbon black was added to this binder mixture.
The spectral reflection of the samples was plotted in the range 400 to 980 nm; the plotted results are illustrated in
The plotted results as shown in
The samples were bonded to a panel of expanded polystyrene and measured with a radiation thermometer exposed to 98000 Lx solar radiation.
The black woven coated in accordance with the invention heated up to 54.5° C. The black woven in accordance with the comparison example heated up to 67.5° C.
The coating was applied wet with a spiral applicator 3×100 μm to the pre-dyed random laid non-woven and then dried.
The same random laid non-woven was coated with a grey standardized coating. The standardized coating consists of an acrylic-copolymer emulsion and an aqueous polyurethane dispersion. For greying, an aqueous pigment dispersion of titanium dioxide (rutile), black ferrous oxide and an aqueous dispersion of carbon black was added to this binder mixture.
The spectral reflection of the samples was plotted in the range 400 to 980 nm; the plotted results are illustrated in
The plotted results as shown in
The samples were bonded to a panel of expanded polystyrene and measured with a radiation thermometer exposed to 98000 Lx solar radiation.
The grey random laid non-woven coated in accordance with the invention heated up to 52.5° C. The grey random laid non-woven in accordance with the comparison example heated up to 63.5° C.
The coating was applied wet with a spiral applicator 3×100 μm to the evenly grey pigmented panel of epoxy resin.
A commercially available grey PVC panel was coated with a grey standardized coating. The standardized coating consists of an acrylic-copolymer emulsion and an aqueous polyurethane dispersion. For greying an aqueous pigment dispersion of titanium dioxide (rutile), black ferrous oxide and an aqueous dispersion of carbon black was added to this binder mixture.
The spectral reflection of the samples was plotted in the range 400 to 980 nm; the plotted results are illustrated in
The plotted results as shown in
The samples were bonded to a panel of expanded polystyrene and measured with a radiation thermometer exposed to 94000 Lx solar radiation.
The grey panel coated in accordance with the invention heated up to 51.5° C. The standardized coated panel in accordance with the comparison example heated up to 61.5° C.
The coating was applied wet with a spiral applicator 3×100 μm to the evenly grey pigmented panel of foamed epoxy resin and died.
The commercially available PVC panel as cited in the comparison example 5 was used for the comparison example.
The spectral reflection of the samples was plotted in the range 400 to 980 nm; the plotted results are illustrated in
The plotted results as shown in
The samples were bonded to a panel of expanded polystyrene and measured with a radiation thermometer exposed to 98000 Lx solar radiation.
The grey panel coated in accordance with the invention heated up to 50.5° C. The coated panel in accordance with the comparison example heated up to 65° C.
The coating was applied wet with a spiral applicator 3×100 μm to the beige dyed leather and then dried.
A beige pre-dyed leather was coated with a beige standardized coating. The standardized coating consists of an acrylic-copolymer emulsion and an aqueous polyurethane dispersion formulated as specified for the particular application with commercially available waxes, fillers, casein and oil. For beige dyeing an aqueous pigment dispersion of titanium dioxide (rutile), brown and red ferrous oxides and an aqueous dispersion of carbon black was added to this binder mixture.
The spectral reflection of the samples was plotted in the range 400 to 980 nm; the plotted results are illustrated in
The plotted results as shown in
The samples were bonded to a panel of expanded polystyrene and measured with a radiation thermometer exposed to 98000 Lx solar radiation.
The beige leather coated in accordance with the invention heated up to 45° C. The beige leather in accordance with the comparison example heated up to 53.5° C.
The coating was applied wet with a spiral applicator 3×100 μm to the evenly grey pigmented panel of epoxy resin and dried.
The spectral reflection of the panel thus produced as well as the heating up due to solar radiation were plotted the same as with the standardized coated epoxy panel in accordance with the comparison in example 5. The results are the same as described in example 5.
The coating was applied wet with a spiral applicator 3×100 μm to the evenly grey pigmented panel of foamed epoxy resin and dried.
The spectral reflection of the panel thus produced as well as the heating up due to solar radiation were plotted in comparison with the standardized coating in accordance with the comparison in example 6. The results are the same as described in example 6.
The coating was applied wet with a spiral applicator 2×200 μm to the foamed epoxy resin and oven-dried.
A commercially available grey PVC panel was coated with a grey standardized coating. The standardized coating consists of an acrylic-copolymer emulsion and an aqueous polyurethane dispersion. For greying an aqueous pigment dispersion of titanium dioxide (rutile), black ferrous oxide and an aqueous dispersion of carbon black was added to this binder mixture.
The spectral reflection of the samples was plotted in the range 400 to 980 nm; the plotted results are illustrated in
The plotted results as shown in
The coating was applied wet with a spiral applicator 3×100 μm to the dyed leather and then dried.
The standardized black dyed and coated leather as cited in example 1 was used as the comparison example.
The spectral reflection of the samples was plotted in the range 400 to 980 nm; the plotted results are illustrated in
The plotted results as shown in
The samples were bonded to a panel of expanded polystyrene and measured with a radiation thermometer exposed to 98000 Lx solar radiation.
The black leather coated in accordance with the invention heated up to 58° C. The black leather in accordance with the comparison example heated up to 67° C.
The coating was applied wet with a spiral applicator 3×100 μm to the evenly grey pigmented panel of foamed epoxy resin.
A commercially available grey PVC panel was coated with a dark green standardized coating. The standardized coating consists of an acrylic-copolymer emulsion and an aqueous polyurethane dispersion. For the dark green colouration an aqueous pigment dispersion of titanium dioxide (Hostatint made by Hoechst), black ferrous oxide and a green pigment dispersion (Hostatint Grün GG30) was added to this binder mixture.
The spectral reflection of the samples was plotted in the range 400 to 980 nm; the plotted results are illustrated in
The plotted results as shown in
The samples were bonded to a panel of expanded polystyrene and measured with a radiation thermometer exposed to 98000 Lx solar radiation.
The dark green panel coated in accordance with the invention heated up to 53.5° C. The dark green coated PVC panel in accordance with the comparison example heated up to 64° C.
The mixture was dispersed, applied wet with a spiral applicator 1×100 μm to a lab type lacquer test plate and oven dried.
The coating was applied wet with a spiral applicator 1×100 μm to the substrate produced as per 13a) and then dried.
A commercially available anthracite black lacquer was applied wet with a spiral applicator 2×100 μm to a lab type lacquer test plate and oven dried.
The spectral reflection of the samples was plotted in the range 400 to 980 nm; the plotted results are illustrated in
The plotted results as shown in
Number | Date | Country | Kind |
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100 38 381 | Aug 2000 | DE | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
---|---|---|---|---|
PCT/EP01/09020 | 8/3/2001 | WO | 00 | 8/14/2003 |
Publishing Document | Publishing Date | Country | Kind |
---|---|---|---|
WO02/12405 | 2/14/2002 | WO | A |
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Number | Date | Country | |
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20040018360 A1 | Jan 2004 | US |