NL2002577C2 - INFRARED LIGHT CONVERTING COMPOSITIONS. - Google Patents

Description

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INFRARED LIGHT CONVERTING COMPOSITIONS

The present invention relates to a light conversion stimulating composition with the property of at least one of its components, with which invisible light is converted into visible light.

The invention further relates, inter alia, to a polymeric material which contains the aforementioned composition.

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Such compositions are known from NL-1017077. From this, a number of compositions and activators are known that convert ultraviolet (UV) light into visible light. Also mentioned are a few other compositions and pigments which can convert infrared (IR) light into visible light, which, however, all have a complex structure, the manufacture of which is complicated, and which is not very difficult to manufacture commercially in larger quantities.

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The object of the present invention is to provide a composition which is capable of converting, with a high energetic efficiency, light with a wavelength that lies in the (in humans) invisible part of the spectrum into light that is in the visible part of the spectrum.

To that end, the composition according to the invention has the feature that the component comprises Y203 to which at least one up-converting and / or down-converting activator is added.

Practical tests have shown that the component containing only yttrium oxide is very suitable to act as a composition with one or more relevant activators which can cause conversion of invisible light into visible light with great efficiency. If desired, the same component Y203 can be activated with several different activators to convert light from several different frequency bands, such as UV 5 and / or IR, to light in the visible part of the spectrum. Moreover, the composition can easily be manufactured on a larger scale and mixed with a polymer material, in which, if desired, even more known phosphors and associated activators can be incorporated which, for example, can also convert visible light into visible light at a desired frequency. This results in multiple light-converting end materials that concentrate light energy from different parts of the light spectrum in a simple manner into a desired (visible) part of the light spectrum. For example, that desired part is the part to which plants are sensitive and in which they thrive, grow and, for example, form fruits.

The composition concerns the possible use of combined inorganic phosphors on polymeric materials for use in agriculture and horticulture, but also in integrated medicine, whereby optimum energy efficiency is achieved by means of a broad luminescence band in the visible spectrum. This is also advantageous in the castle where IR or heat radiation can be kept out and converted to more useful light.

Furthermore, a suitable light is found to cure a number of disorders, and that has a positive influence on various living biological structures. The composition can be used, for example, in a structure or a carcass with a polymer coating attached thereto with properties of UV and / or IR light conversion to the visible spectrum.

The sun is the main natural source of radiation in the visible spectrum, ranging from 380-830 - 3 - nm. An invisible part of the spectrum is in the wavelength region of the UV radiation, but also includes the infrared region. The UV region is divided into three regions according to the wavelength: UV-C (100-290 nm), UV-B (290-320 nm) and UV-A (320-400 nm). The infrared component that is important as a heat source for earthly life is divided into three areas: IR-A (780-1400 nm), IR-B (1400-3000 nm) and IR-C (3000-1.0 mm).

The white light emitted by the sun contains a mixture of different wavelengths in the visible spectrum. Most of them are essential for photosynthesis of oxygen by plants. In promoting the growth and flowering of plants, blue (400-480 nm) and red (625-735 nm) light are of great importance. These wavelengths influence the periodicity (the moment of flowering) and the morphology (the shape of the plants). The red area is the so-called 'action spectrum'. This action spectrum is closely related to the absorption spectrum of the light-absorbing complex in the plant. The chloroplast: the colorant or pigment it contains, the chlorophyll, captures the light energy and transforms it into chemical energy in the form of sugars and other energy-rich substances that form the body of the plant. The chlorophyll absorbs a lot of red and blue light, but reflects the green light.

The light-converting compositions to be incorporated into the polymer materials usually have a high absorption in the ultraviolet and / or infrared region and convert absorbed UV / IR energy photons from the invisible part of the light spectrum to the visible light spectrum. A suitable mixture can be made with one or more of the following combinations of compositions with rare earth metals or lanthanides listed in Table I below as an activator. These compositions at least cooperate, stimulate and / or initiate the conversion of UV light into light from the visible part of the spectrum, which has the emitted color indicated in the fourth column.

Composition Activator A [nm] Color 5 La202S_Eu3 + _628_red

Gd202S_Eu3 + _635_red Y202S_Eu3 + _62 5 red (Zn, Cd) S_Ag_red YV04_Eu3 + _650_red 10 (Y, Gd) B03_Eu3 + _611_orange and Y202S_Tb, Eu_630_red

SrS_Eu3 + _ 63 0_red

NaCdS2_Eu2 + _red Y203_Eu_612_oranj e 15 NaYS2_Eu2 + _red

InB03_Eu_592_orange (Sr, Zn) 3 (P04) 2 Sn_595_orange and Y2Q3_Dy_575_yellow Y3A15012_Ce_555_yellow 2 0 Gd2Q2S_Tb_544_yellow-green Y3 (A1, Ga) 5012 Tb_5ng-yellow_Green_Green_Green_Green_Green_Green_Green_Green

CaSi03_Mn, Pb_540_yellow green

MgF2_Mn_561_yellow 25 SrGa2S4_Eu_535_green blue

ZnO_Zn_502_green

BaMg2All6027 Eu3 + _450_blue

Sr5 (PO4) C1_E3 + blue

GdAlO3_Ce_blue 30 Gd202S_Pr, Ce, F_green

Gd202S_Pr_green

CeMgAll1013 Tb3 + _545_green

Table I 35 - 5 -

The combinations of compositions or phosphors and activators can not only emit visible light (or convert) when irradiated with energy-rich UV radiation (down-conversion), but can also convert in particular infrared radiation (up-conversion) into visible light. Some activators thus up-converting or down-converting have such a level scheme that a step-by-step absorption of energy is possible.

By absorbing two photons from the infrared radiation, a level is reached from which emission can occur in the visible light spectrum by falling back to the ground state. We speak of an anti-Stokes phosphor in such a case, because the wavelength of excitation is greater than that of emission. In this process, two photons of lower energy are converted into a photon of higher energy. This process is called up-conversion and suitable combinations of compositions and activators, with which in particular this process can be realized, are indicated in Table II below.

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Composition Activator A [nm] Color

CaS_Eu, Sm_650_red

SrS_Eu, Sm_red

CaS_Ce, Sm_510_green blue ZnS_Cu, Pb_490_blue

ZnS_Cu, Pb, Mn_590_orange Y203_Yb, Er_661-685 red

Table II 30

By using one or more compositions listed in Tables I and II, apart from Y 2 O 3, several possibilities are provided for combining one or more high-efficiency emission colors suitable for the application. With a high energy efficiency, a large part of the primary energy is converted into emission radiation, which, for example, stimulates plant growth.

Polymeric materials based on different phosphorus components can be used in or as a film, cover layer, sheet material, film layer, pourable or sprayable liquid substance, or as a building element. This includes thermoplastic polymers, or a coating composition with natural or synthetic glass. For the thermoplastic polymers, use can be made of different polyesters, such as polymethyl methacrylate, polybutene methacrylate, polycarbonate, polyethylene terephthalate (PET), or polyolefins, such as polypropylene, polyvinyl chloride, polystyrene, polyethylene, or polyamide, such as polyamide fiber (nylons), acrylic fibers, or their copolymers. The polymers can also form a transparent coating based on polyester or poly-epoxy resin.

For example, a polymer composite material can be applied to transparent glass such as silicate glass, or polyester resins and other silicones can be used. Synthetic fibers provided with the aforementioned composition can also be used, examples of which are: silk fibers, a combination of wool and cotton, "semi-synthetic" cellulose fibers, including rayon, cell wool and cellulose acetate, and the "fully synthetic", of which nylon, polyester and polyacrylonitrile are the most important. These polymeric materials to which luminescent phosphorus components have been added then form the light-converting compositions.

An interesting field of application of polyethylene and polyester plastics for use in glass and horticulture can be found in the cultivation of crops. The light-converting foil is then, for example, applied to the glass (on the outside) of the greenhouses. The composition applied to the film contains, for example, BaMg2All6027 with activator Eu3 + and Y203 respectively with activator Yb and / or Er in the ratio of 2: 3 to 1: 4 respectively. The phosphor pigments: BaMg2All6027: Eu3 + and Y203: Yb. There are present in the film in a weight ratio to the polymer of 0.3% and 0.75%, respectively. The end material produced in practice is a hard clear microperforated polypropylene film PP or PET (polyethylene terephthalate with a thickness of approximately 200 µm). The glass plastic is not entirely clear, but gives a slightly diffuse transmission of the light. The 10 beneficial effects of the foil on glass are: - The transparency of plastic on glass is 87-92% - The transmission in the UV area is even reduced by 20-30% - With perpendicularly striking radiation, the reduction in light transmission remains limited up to 3%.

15 Measured effects when growing roses. The production level of the roses in the summer period 2004 was approximately 10% higher under the glued-on foil than under the lightly chalked deck. The growth rate was higher under the window film than under the chalk glass. Various have also been reported as an advantage of the film: absorption of harmful UV light, generation of diffuse light, better insulation. All this also leads to greater efficiency, respectively mind damage, better lighting, less lighting, less heating.

25 Glass plastic also provides an energy saving of around 3% with the use of 50 m3 of gas per m2, which amounts to a saving of 1.5 m3 in the winter. The energy saving also increases, because if there is no chalk on the greenhouse, there is no need to illuminate in the greenhouses, because the glass plastic allows more light than the chalk. The chalk is normally present continuously from mid-April to mid-September to shield the sun, because otherwise a rose crop receives too much radiation, resulting in shorter roses with finer leaves.

In the cultivation of tomatoes, approximately 10% -8 growth improvement was observed if the lower light intensity was taken into account under the respective growing conditions. The developed material can make an important new contribution to the prevention of UV or IR damage, whereby not only UV or IR is blocked or reflected, but that as a result of the light conversion the energy from it can benefit the photosynthesis process. Thanks to the scratch-resistant coating, the foil can be treated as normal glass and is therefore completely maintenance-free. Other advantages of this material: protection of atmospheric dirt and hail, thermal insulating properties, reinforcement of the glass up to 18 times, whereby the consequential damage in the event of glass breakage is kept to a minimum, a beautiful view, fire and burglary retarding, absorption of UV and IR radiation and conversion of the energy generated in the PAR (red, blue and green or yellow), lifespan at least 3-5 years.

The amounts of the phosphorus constituents to be added in the polymeric materials range from a minimum of 0.001% to a maximum of 5.0% of the mass. The saturation limit can be shifted to higher light intensities by: l. increasing the concentration of the luminescent materials and their activators; 2. by adding boric acid H3 BO3 or B (OH) 3. Boric acid has the property of significantly extending the red light in the spectrum relative to the blue light.

Test results in the summer of 1998 in crop cultivation with light-transparent experimental glass coating from fast-drying alkyd resin with a phosphorus concentration of 0.75% (7500 PPM) on a glasshouse filled with various herbs, tomatoes and peppers have shown that the size of the fruits, from the green mass of tubers was 20-50% compared to the control group (greenhouse without coating with the same dimensions and arrangement). It is assumed that the - 9 - emission spectrum (450nm, 635nm and 708nm) of the light-converting glass coating shows an optimal overlap with the known action spectrum for the photosynthesis process. In addition, it contains sufficient extra emission bands to stimulate the photosensitive and pigment-containing sensor proteins present in plants. As is known, these sensors serve as a signal generator for morphogenesis and for other reaction chains and reaction cycles of interest.

The polymer with the additives is formed on the glass as inner or outer layer into layers of 20-200 µm. Thick films are obtained by extrusion of plastic granules or powders. The polymer is first cold mixed with the phosphor powder combination, and then heated to 120 ° C with stirring. This mixture is then converted into a homogeneous mass at temperatures up to 180 ° C or more, and this is introduced into an extrusion press, from which a thick plastic emerges. The area between Tg (glass transition temperature) and Tm (melting point) for crystalline polymers is characterized by a stiffness that is lower than for glassy polymers, but higher than for rubbers. Their modulus is relatively strongly temperature dependent, while their impact resistance is considerably better than that of plastics in the glass state.

Typical examples of plastics used in this so-called

tough areas have their use value, are polyethylene and polypropylene. In the amorphous state, these would be soft rubbery substances at room temperature. Other crystalline polymers are polyamides and polyesters. These are in the glass state at room temperature; their crystallinity ensures that they are above Tg (50 ° C and 70 ° C, respectively), although softer, in the solid state up to their melting point Tm (230 ° C and 260 ° C, respectively). The synthetic polymers as supplied by the chemical industry are often available in granular or powder form.

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The end products must now be manufactured from various design techniques, such as foils, tent cloth, sheets, film layers, or building elements, for example.

5 End products can also be made for use in light therapy for medical applications.

Example 1:

A mixture of 100 parts by weight of low-density polyethylene or polyethylene terephthalate granules (extrusion type suitable for film production), 1000-7500 ppm parts (0.001-5%) wt% of an infrared up-converting luminescent pigment Y203: Yb, Er, 1000 ppm parts of BaMg2Al116027: Eu3 + (particle size 2-10 µm) and 4000-8000 ppm wt% of oligomeric Neck light stabilizer, a mixture was formed and processed in an extruder and extruded around a film with a thickness of 20-200 pm. Color emission was with blue and red light with UV excitation.

Example 2:

A film with a thickness of 20-200 µm was prepared in the same manner as in Example 1, except that instead of the BaMg2All6027: Eu used an Sr5 (PO4) 3Cl: Eu or other blue luminescence pigment from Table I was applied. The color emission was with blue / red light on excitation with UV light.

Example 3:

A film with a thickness of 20-200 µm was prepared in the same manner as in Example 1 with the exception that instead of BaMg2All6027: Eu a CaS: EuSm or other IR up-converting luminescent pigment from Table I was used. Color emission was due to the red light, and excitation in the UV-A and IR-B region of the spectrum.

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Example 4

The combination of the said luminescent phosphors in Examples 1-3 can be used in polymer materials such as polydimethylsiloxane, polyethylene, cis-1,4-polybutadiene, cis-1,4-polyisprene, polyisobutene, trans-1,4-polyisoprene, polychloroprene, polyoxymethylene , polyvinylidene chloride, polypropylene, polyvinyl acetate, polychlorotrifluoroethylene, nylon-6, nylon-6,6, cellulose nitrate, polyethylene terephthalate, cellulose acetate, polyvinyl alcohol, polyvynil chloride, polystyrene, cellulose triacetate, polyvinyl acrylate, polyethyl polyethylene polycarbonate, polyethyl polyethylene polycarbonate, polyethyl polyacrylite a mixture of polymers.

Claims (11)

A light conversion stimulating composition with the property of at least one of its components, with which invisible light is converted into visible light, characterized in that the component comprises Y203 to which at least one up-converting and / or down-converting activator is added. Composition according to claim 1, characterized in that one or more components are selected from the group comprising: La 2 O 2 S, Gd 2 O 2 S, Y 2 O 2 S, ZnS, CdS, YVO 4, YBO 3, GdBO 3, SrS, NaCdS 2, NaYS 2, InBO 3, Sr 3 (PO 4 ) 2, Zn3 (PO4) 2, Y3A15012, Y3Ga5012, KMgF3, CaSi03, MgF2, SrGa2S4, ZnO, BaMg2All6027, Sr5 (PO4) Cl, GdAlO3, Gd2O2S, CeMgA111013, CaS. Composition according to claim 1 or 2, characterized in that the at least one activator is selected from the group comprising: Eu, Eu3 +, Eu2 +, Ag, Tb, Eu, Ce, Tb3 +, Pr, Ce, F, Sm, Sn, Dy, Mn, Pb, Zn, Cu, Yb and Er. 4. Composition as claimed in any of the claims 1-3, comprising BaMg2All6027 with activator Eu3 + and Y203 respectively with activator Yb and / or Er in the ratio of 2: 3 to 1: 4 respectively. A polymeric material comprising the composition of any one of claims 1-4. Polymeric material according to claim 5, characterized in that the polymeric material is selected from the group consisting of: polydimethylsiloxane, polyethylene, cis-1,4-polybutadiene, cis-1,4-polyisprene, polyisobutene, trans-1,4-polyisoprene, polychloroprene, polyoxymethylene , 35 polyvinylidene chloride, polypropylene, polyvinyl acetate, - 13 - polychlorotrifluoroethylene, nylon-6, nylon-6.6, cellulose nitrate, polyethylene terephthalate, cellulose acetate, polyvinyl alcohol, polyvynilchloride, polystyrene, cellulose triacetate, polyvynilformal, 5 polymethyl methacrylate, polyacrylonitrile, polytetrafluoroethylene, polycarbonate, polyvinyl carbazole, their copolymer, and / or a mixture of polymers. 7. Polymeric material according to any of claims 5-7, with reference to claim 4, wherein the ratio between BaMg2Al116027 and Y203 is around 0.3% and 0.75% by weight, respectively, measured with respect to the weight of the polymer material. Polymer material according to one of claims 5 to 7, characterized in that the polymer material contains a combination of La 2 O 2 S: Eu 3+ and BaMg 2 Al 2 O 60 27: Eu 3+. 9. Polymer material according to claim 8, characterized in that the combination contains La 2 O 2 S: Gd and / or Gd 2 O 2 S: Tb in a concentration of 1000-8000 PPM. 10. Foil, plate, film layer, pourable or sprayable liquid substance, or building element composed of a composition according to any of claims 1-4 and / or a film material according to claims 5-9. 11. Use of the light conversion properties composition according to any of claims 1-4 and / or the polymer material according to any of claims 5-9 for influencing the spectrum of transmitted light for use in agriculture and horticulture, and / or in medicine, including light therapy.