WO2012140242A1 - Photoluminescent composite material - Google Patents

Abstract

The invention relates to a composite material having persistent-photoluminescence properties, the persistent glow of which is greater than 1100 mcd/m² after said material remains in the dark for 10 minutes, comprising: - a binder material transparent to the radiation within a spectral range of between e.g. 400 nm and 700 nm; and photoluminescent pigments, wherein the concentration by volume or by weight of the binder material can be between 30% to 100%, and the individual size thereof can be between 5 µm and 1000 µm.

Description

 PHOTOLUMINESCENT COMPOSITE MATERIAL

DESCRIPTION

TECHNICAL FIELD AND PRIOR ART

The invention relates to the field of compositions having strong luminescence at night or in dark conditions.

 In this field, there are known compositions and devices of the type described in US 5904017.

 This technique uses products that comply with DIN 67510 (quality A). More precisely, it uses zinc sulphide, which is also very fragile and not usable in a humid environment.

 There is therefore the problem of finding a new composition with improved luminescence characteristics compared to currently known compositions and implemented.

 There is also the problem of finding a new composition with a high resistance to bad weather, especially rain and moisture.

STATEMENT OF THE INVENTION

The invention relates firstly to a composite material with photoluminescence remanent properties comprising: a binder or matrix material which is transparent to radiation in a spectral range of, for example, between 400 nm and 700 nm;

 photoluminescent pigments whose concentration in volume or weight, relative to the material forming the binder, may be between 30% to 100%, and the individual size of said pigments may be between 5 μm and 1000 μm.

 According to an alternative, the composite material may comprise a concentration in volume or weight of photoluminescent pigments, relative to the material forming the binder, of between 30% and 50%, or between 30% and 60%, or between 50% and 60%. %, or between 50% and 80%, or between 60% and 80%, or between 50% and 100%, or between 60% and 100%, or between 80% and 100%.

 According to another alternative, the composite material may comprise photoluminescent pigments whose individual size may be between 5 μm and 30 μm, or between 30 μm and 80 μm, or between 80 μm and 1000 μm.

The photoluminescent pigments are preferably crude, that is, the photoluminescent pigments are not treated before being incorporated in the binder. This advantageously makes it possible to promote the mechanical maintenance of the composite material, more particularly when said material is in contact with water and / or the concentration by weight of the photoluminescent pigments is important, for example greater than 80%. The inventor has in fact surprisingly found that a composite material, in contact with water, has a higher mechanical strength. significant when it comprises raw photoluminescent pigments, compared to composite materials comprising treated photoluminescent pigments.

 The density or densities of the photoluminescent pigments present in the binder may be equal to or less than the density of the material forming the binder or the matrix.

 If this is not the case, the binder may comprise a transparent filler making it possible to increase the value of the volume density of the binder, so that it is equal to or greater than the density of the photoluminescent pigments. In other words, the binder has a density equivalent to or greater than that of the photoluminescent pigments that it contains, in order to limit or avoid the phenomenon of photoluminescent pigment sedimentation. Thus, the photoluminescent pigments are advantageously suspended in the binder when it hardens. The transparent filler is therefore preferably incorporated in the binder when it is desired to produce a composite material with longer residual photoluminescent properties. It has indeed been found by the inventor that the remanence time of the composite material is proportional to its thickness.

In other words, for a composite material according to the invention, it is preferable that the photoluminescent pigments do not sediment when said material is shaped. The transparent filler can be a gelling type material, such as thixotropant.

 The transparent filler may have a proportion by weight, relative to the binder, of between 1% and 3%.

A composite material according to the invention has an increased night-light intensity, which may be greater than 1,100 mcd / m ² , or greater than 1,500 mcd / m ² , or greater than 1,800 mcd / m ² after 10 minutes of presence of the composite material in the dark. These values have been measured in particular according to the internationally recognized DIN 67510 standard for the evaluation of light density and the period of weakening of brightness. These measurements showed that a composite material can have a brightness 2 to 4 times more powerful and 6 to 10 times longer than class A or DIN 67510.

 A material according to the invention can be used both inside or outside buildings, or in water.

 The binder used can receive or have previously received any dye, for any primary or secondary color, but preferably very transparent.

According to a particular embodiment, it is possible to achieve one or more color variations, for example between day and night, depending on the temperature, by adding thermal pigment. A thermal pigment with the property of being transparent when its temperature is stable, but to be colored when its temperature varies.

 The binder material may comprise a colorless epoxy resin or a polyester, or polyurethane, or polyacrylic resin.

 According to one variant, the binder can be formed from a transparent aqueous base, in order to obtain a composite material of the water-based paint type, that is to say, having no solvent.

 A composite material according to the invention may be formed or arranged on a reflective substrate, the surface of the reflective substrate on which the binder may be white, for example of "RAL" color 9016 or "Pantone" 705. Advantageously, a Light color promotes the reflection of the light emitted by the composite material to the outside.

 The invention also relates to a building element for the building industry, comprising a substrate and a coating made of a composite material according to the invention.

 For example, the substrate may be a brick or be cement-based or concrete still be wood or plastic, or tile joint.

In another example, a composite material may be on and / or in a transparent or non-transparent substrate, to indicate the presence of said substrate in the dark. In other words, a composite material can make it possible to signal the position of an object, for example a switch frame, in order to facilitate its location and / or its use in darkness. An object comprising the composite material can then have a new function, night-light type.

 The invention is more particularly advantageous when it is present on textile elements in contact or may be in contact with water. Indeed, the properties of photoluminescence remanent composite material are preserved in contact with water.

 Thus, the invention may relate to a textile comprising a composite material according to the invention, for example a garment, a rope or other ... Advantageously, a luminescent material may be deposited in and / or on the surface of a flag, to make it easier to locate in the dark or in a dimly lit environment.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 represents the operating principle of a composite material according to

The invention;

 FIG. 2 represents a variant of a composite material according to the invention.

 - Figure 3 shows a brick provided with a coating of a material according to the invention.

- Figure 4 shows a building element incorporating a coating of a material according to the invention. FIG. 5 shows measurements of the luminance restored by a first sample as a function of time.

 FIG. 6 represents measurements of the luminance restored by a second sample as a function of time.

DETAILED PRESENTATION OF PARTICULAR EMBODIMENTS

A first embodiment of the invention will first be described with reference to FIG.

 A binder or matrix material 2, for example a colorless epoxy resin, comprises strontium aluminate pigments 4, preferably from 30% to 100% by volume or by weight.

 This binder is transparent to light, more precisely to electromagnetic radiation having at least one wavelength comprised, for example, between 400 nm and 750 nm, or between 450 nm and 700 nm, or between 500 nm and 650 nm. In the wavelength range chosen, and for the thicknesses of materials envisaged (from a few tenths of a millimeter up to a few tens of millimeters, see below) we will preferably have a transmission coefficient close to 1, or in any case greater than 0.9, or 0.8.

 The binder is for example a polyester type resin, or polyurethane, or polyacrylic, or Resoltech type 1070s.

The binder can also be formed from one of the preceding compounds, in the form of a base transparent water. A transparent aqueous base may advantageously be used to produce a water-based paint, optionally stained with photoluminescent pigments as described below.

 The binder can be a screen printing ink

UV, that is to say, possibly dried by the use of a UV lamp.

 Alternatively, the binder may be polycarbonate type, or ABS or PET. In this case, it is prepared by molding. In this case, a composite material according to the invention may comprise a binder or a matrix whose density is lower than that of the pigments, in order to limit their sedimentation during molding. Optionally, a transparent filler may be incorporated into the binder for this purpose.

 In other words, a transparent filler is advantageously used when it is desired to promote the phenomenon of suspension of the luminescent pigments in a composite material, in the form of an ink or a molded part.

A composite material according to the invention can be colored on demand, according to all day colorations. For this purpose, photoluminescent transparent dyes may be incorporated into the binder as long as the composite material obtained has a transmission coefficient greater than 0.8 or 0.9. In other words, the binder can be colored by photoluminescent pigments of different colors, as long as an incident wave, included in the visible range, can cross two times in succession said material and be visible by the human eye. The photoluminescent staining pigments, for example of strontium aluminate, have a size or a particle size, that is to say an average grain size, which may be between 5 μm and 30 μm, or between 30 μm and 30 μm. 80 μm, or between 80 μm and 1000 μm. Preferably, 90% of the grains have a size in one of the previous average size ranges.

 A strontium aluminate pigment may have yellow or green, or blue, or red luminescence. The inventor has found that, in the context of the present invention, it will be preferable to use a yellow or blue-green luminescent pigment, this type of pigment providing a better effect in terms of luminescence.

 It is also possible to use a binder having a certain non-luminescent color, for example red, with a photoluminescent pigment of another color, for example blue. In this case, there will be a red color, due to the binder, in the light or during the day, and a blue color in the dark or during the night, resulting from the combined effect of the photoluminescent pigment and the binder. Preferably, the volume proportion of the non-luminescent pigments present in the binder is between 1% and 6% or between 1% and 3% in order to preserve the transmission properties of the binder.

The samples shown in FIGS. 1 and 2 have a thickness E of, for example, between 0.5 mm and 50 mm, for example still between 2 mm and 20 mm. The interaction of the light and the composite material according to the invention is illustrated in FIG. 1. A luminous flux, symbolized by the arrows 12, circulates in the mass of the material, between the pigments 4, this flow coming from the penetration of the external light, for example natural light or else an artificially produced light, by one or more lamps or by a lighting device. For example, a lighting device may be a source of wavelength emission between 365 nm and 385 nm, to promote the excitation of photoluminescent pigments.

 In the composite material the photoluminescent pigments themselves store a portion of the radiation 10, and then re-emit later.

 In the embodiment of FIG. 2, a white background 14 makes it possible to reflect this light. This white background has for example a color of the type 9016 "RAL" or "Pantone" 705. Other types of reflectors may be used, for example a mirror surface, or any other reflective material.

With a structure of the type of that of Figure 2, with white background 14, luminescence measurements were made according to the international standard 67510 DIN. This standard is internationally recognized for the assessment of light density and the period of weakening of brightness. The measurements are carried out by illuminating a composite material according to the invention (FIG. 2) with a Xenon arc (reference LNE 1003595) for 30 minutes. The illuminance is 1,500 ± 80 lux. Luminance measurements are made in total darkness with a luminance meter (LNE reference 1036148), every two minutes after the end of the exposure. The front face of the detector of the luminance meter, comprising the light detector, is deposited on and in relation to the composite material. As a result, the luminance field analyzed corresponds to the shape of the detector, circular and 50 mm in diameter.

 The measurements were made on a first sample, composed of a white textile, covered with a water ink according to the invention. The ink is composed of a water-based polyurethane binder, more specifically 0.9-1.5 N-ethylmorpholine, comprising photoluminescent aluminate pigments. The size of the pigments is of the order of 40 μm and their concentration by weight relative to the binder is of the order of 50%. The thickness of the ink is 100 pm on the textile. These measures are reported in Table 1 below and on the

Table 1 Measurements have also been made, according to the same international standard, on a second sample of a composite material, in the form of a grain or a stud, whose thickness is of the order of 10 mm. The composite material is composed of a binder similar or identical to the previous binder, also comprising photoluminescent aluminate pigments. Their concentration by weight, relative to the binder, is of the order of 50% and their size is of the order of 350 pm. Again, the sample is deposited on a white reflector. These measurements are reported in Table 2 below and in Figure 6. The table gives the measurements in mcd / m ² .

 Table 2

These measurements show that the minimum restored luminance of a composite material according to the invention, depending in particular on its composition and its thickness, may be greater than 180 mcd / m ² or greater than 1100 mcd / m ² after 10 minutes, and greater than 30 mcd / m ² or greater than 75 mcd / m ² at the end 60 minutes. The composite material has an extinction time of the order of 48 hours or more.

Compared to DIN 67510 type products, a composition according to the invention has a luminance of 3mcd / m ² after 20 hours (1200 minutes), so 20 times higher. In addition, a composition according to the invention has a total extinction (luminance less than 0.3 mcd / m ² ) after more than 100 h, ie about 5 days (value established with a certified photometer and according to DIN 67510).

 Alternatively, a composition according to the invention may further incorporate a fluorescent pigment, different from the pigment 4 already presented above. Such a fluorescent pigment makes it possible to obtain a fluorescence effect in the light or during the day, whereas, in the dark or during the night, it is the luminescence effect, already presented above, which occurs .

 A composition according to the invention may be prepared by molding, preferably cold. Strontium aluminate pigments (50 to 100% by volume or weight) are incorporated in this binder with the particle size indicated above. Alternatively, it may be embedded or embedded in any material.

A composition or a material according to the invention can be used in various forms, for example on the surface of a building material intended to be visible outside a building. It is represented in FIG. 3 in the form of a coating 22 of a brick 20. It can thus be in or on a portion subject to moisture or water, especially in a swimming pool, for example on a support such as a brick or concrete or a panel covering these surfaces or supports. The pigment 4 does not fear moisture and, in addition, it is protected by the binder 2.

 It can also be used indoors, for example as a decorative motif. Thus, it can be used in particular as an element 32, 34, 36 incorporated in or on a panel 30, for example still intended to be used as a lining panel of a building, as illustrated in FIGS. 4A and 4B. The material according to the invention can for example be made in the form of a strip 32 and / or in the form of dots or circular zones 34, 36. It is possible to produce more complex shapes, for example drawings or inscriptions. or commercials.

 A water-based paint according to the invention is less harmful to the environment for making screen printing prints, for example on textile materials: clothes, flags, ropes, sails ...

 A composition according to the invention can therefore be used in combination with any support, whether brick or cement-based or concrete, or wood, or plastic, or textile material. The binder 2 provides adhesion or mechanical support on the surface or the support.

Alternatively, it is possible to place a panel of a material according to the invention against a surface or a support of one of the types mentioned above, and to fix this panel to this surface.

 In another variant, a material according to the invention may be projected onto the surface or the support in question.

 The invention applies to all areas requiring element-based decoration visible in dim light or darkness.

Claims

1. Composite material with photoluminescence remanent properties, whose remanence is greater than 1100 mcd / m ² after 10 minutes of presence of said material in the dark, comprising:  a binder material which is transparent to the radiation in a spectral range of, for example, between 400 nm and 700 nm,  photoluminescent pigments whose concentration in volume or in weight of the material forming the binder may be between 30% to 100%, and their individual size of between 5 μm and 1000 μm. 2. Composite material according to claim 1, the material (2) forming a binder comprising a colorless epoxy resin or a polyester type resin, or polyurethane, or polyacrylic. 3. Composite material according to claim 1, the composite material being a water-based paint formed from a binder comprising a water-based polyurethane transparent resin. 4. Composite material according to claims 1 to 3, further comprising a reflective substrate (14). Composite material according to claim 4, the surface of the reflective substrate on which rests the binder being white, for example of color of the type "RAL" 9016 or "Pantone" 705. 6. Composite material according to one of the preceding claims, further comprising pigments of one or more colors, and / or thermal pigments. 7. Composite material according to one of the preceding claims, further comprising one or more fluorescent pigments. 8. Construction element, of the type used in the building industry, comprising a substrate (20, 30) and a coating made of a composite material according to one of claims 1 to 7. 9. Construction element according to claim 7, the substrate (20) being a brick or cement-based or concrete. 10. Construction element according to claim 7, the substrate (30) being of wood or plastic. 11. A textile material comprising a coating made of a composite material according to one of claims 1 to 7. 12. Textile material according to claim 11, the textile material being a flag, a garment, or a rope.