Modified phosphor and composition thereof

Abstract

To provide inorganic phosphors having a modified surface, their manufacture, and their uses in polymeric compositions and articles.SOLUTION: A modified phosphor comprises phosphor particles and at least one amphiphilic agent applied thereonto. The modified phosphor is selected from among phosphors which contain at least one element selected from the group consisting of the rare earth elements, zinc and manganese, and has: an external quantum yield equal to or greater than 40% over at least an excitation wavelength included in the range from 350 nm to 440 nm; an absorption equal to or less than 15% at a wavelength greater than 440 nm; and a maximum in the emission spectrum in a range of wavelengths included in the range from 440 nm to 900 nm.SELECTED DRAWING: None

Description

[Technology Field]

[0001] Cross-reference of related applications This application may also include at least one silane coupling agent to improve the degree of 2014. This application claims priority to European Patent Applications No. 14306234.7 and No. 15305178.4, filed on August 4, 2014 and February 6, 2015, the contents of which are incorporated herein by reference in their entirety for all purposes. In the event of any inconsistency between this application and the European applications affecting clarity of terminology or expression, it should be referred to solely in this application.

[0002] The present invention relates to inorganic phosphorescent materials having a modified surface, their manufacture, and their use in polymer compositions and articles.

[0003] technical issues Inorganic phosphorescent materials, hereafter referred to as "phosphorescent materials," have been known for many years. Among the well-known inorganic phosphorescent materials, examples include mixed elemental materials, such as phosphates and aluminates of rare earth elements.

[0004] The fields of luminescence and electronics are currently experiencing significant development, for example, in the development of plasma systems (displays and lamps) for new technologies in displays, lighting, or marking. Therefore, aside from their luminescent properties, phosphorescent materials are increasingly required to possess specific morphological or particle size characteristics that facilitate their use in the required applications.

[0005] More precisely, for certain applications, it is desirable to obtain materials in the form of thin, transparent, and luminescent films. For this purpose, it is advantageous to have phosphorescent materials dispersed in a polymer without losing their phosphorescent luminescent properties. Solar panels, as well as greenhouses, are two non-limiting examples of these types of applications.

[0006] It has now been found that it is possible to modify the surfaces of a wide range of phosphorescent materials without degrading their optical properties, thereby improving their dispersibility in a polymer matrix.

[0007] definition For the purposes of this invention, the expression "rare earth elements" refers to the group of elements consisting of yttrium and elements of the periodic table having atomic numbers from 57 to 71 (inclusive).

[0008] The predetermined excitation wavelength λ exc The external quantum yield (EQ) is calculated as a percentage ratio between the integral of photon emission of a phosphorus over the emission range of 400–900 nm and the integral of photon emission of a reference phosphorus over the same emission range, where both phosphorus have the same excitation wavelength λ exc It is excited by [the following]. Photon emission may be measured on a dry suspension of the phosphorescent material using a Jobin-Yvon type fluorescence spectrometer.

[0009] The standard phosphorescent material (EQ=100%) is the phosphorescent material obtained according to the procedure described in Example 1 of International Publication No. 2004 / 106263. The raw material used was boehmite sol containing 0.157 moles of Al per 100 g of gel (specific surface area 265 m²). 2 A europium nitrate solution (d=1.5621 g / mol) containing 99.5% barium nitrate, 99% magnesium nitrate, and 2.102 mol / l Eu was prepared, yielding 200 ml of boehmite sol (i.e., 0.3 mol Al). Furthermore, a salt solution (150 ml) was prepared containing 7.0565 g of Ba(NO3)2; 7.9260 g of Mg(NO3)2 and 2.2294 g of Eu(NO3)3 solution. The final volume was supplemented with water to 405 ml (i.e., 2% Al). After mixing the sol with the salt solution, the final pH was 3.5. The resulting mixture was spray-dried in an APV® spray dryer at an outlet temperature of 145°C. The dried powder was calcined in air at 900°C for 2 hours. The powder thus obtained is white. The product is of the formula Ba 0.9 EU 0.1MgAl 10 O 17 which is a precursor of the reference phosphor. The precursor is mixed with 1 wt% (by weight) of MgF2 (1 part of MgF2 and 99 parts of the precursor). The mixture thus obtained is calcined at 1550 °C for 4 hours in an Ar-H2 (5 vol%) atmosphere. Then, the calcined product is washed in dilute nitric acid at 60 °C for 2 hours with stirring, filtered, and dried in an oven at 100 °C for 12 hours. The phosphor obtained is the reference phosphor.

[0010] The average particle diameter d 50 is defined as the diameter of at least 50% of the particles determined by laser diffraction technology using a laser particle size analyzer (volume distribution) for a dilute suspension (aqueous solution or solvent) of the phosphor without ultrasonic treatment and dispersant. Thus, the average particle diameter d 50 is the size that divides the volume distribution into the upper and lower halves of this diameter. The aqueous solution (e.g., water) or solvent is selected such that the particles do not settle and remain in the suspension. The aqueous solution or solvent is also selected such that the particles do not dissolve and remain as they are. This technique allows for obtaining a volume distribution from which parameters such as d 50 d 84 and d 16 are obtained.

[0011] The term "distribution index" means the ratio: σ / m = (d 84 - d 16 ) / 2d 50 (where - d 84 is the diameter of the particles 84% of which have a diameter less than d 84 (determined by laser diffraction technology); - d 16 is the diameter of the particles 16% of which have a diameter less than d 16 (determined by laser diffraction technology); - d 50 is the average diameter of the particles) is understood to mean.

[0012] The term "absorption" is used to refer to the percentage of light absorbed over a wavelength range including 250 nm to 500 nm, as measured by diffuse reflectance using a Perkin Elmer Lambda 900 UV-Vis (UV-VIS) spectrometer.

[0013] Absorption is obtained from the diffuse reflectance spectrum. Such spectra can be recorded using a Jobin Yvon HORIBA fluoromax-3 spectrometer equipped with a xenon lamp and two monochromatic spectrometers that can work synchronously (one for the excitation wavelength and one for the emission wavelength). The first reflectance spectrum of BaSO4 is recorded from 250 nm to 500 nm. The BaSO4 spectrum corresponds to 100% light reflectance (referred to as "white"). The second reflectance spectrum of black carbon is recorded from 250 nm to 500 nm. The spectrum of black carbon corresponds to 0% light reflectance (referred to as "black"). The reflectance spectrum of the sample is recorded from 250 nm to 500 nm. For each wavelength, the following relationship is calculated: A = (R 白色 -R 試料 ) / (R 白色 -R 黒色 (This corresponds to the absorption spectrum at each wavelength.) [Brief explanation of the drawing]

[0014] [Figure 1] Figure 1 shows the absorption spectrum corresponding to the modified phosphorescent material MP1 of Example 1. [Figure 2] Figure 2 shows the emission spectrum of the modified phosphorescent material MP1 of Example 1. [Figure 3] Figure 3 shows the electron microscope (magnification 5000) observation of a composition containing ethylene / vinyl acetate and standard phosphorescent P1 (unmodified). [Figure 4] Figure 4 shows the electron microscope (magnification 5000) observation of a composition containing ethylene / vinyl acetate and modified phosphorescent MP1.

[0015] Background technology International publication brochure No. 2012 / 032880 contains the formula: A wavelength conversion resin containing an inorganic fluorescent substance is described.

[0016] The particle size is not particularly limited, but is preferably between 1 and 1000 nm. The resin monomer may be an addition polymerization monomer, more specifically a vinyl compound containing an ethylenically unsaturated bond. International Publication No. 2012 / 032880 discloses that inorganic fluorescent materials may be coated with a vinyl polymer dispersant having hydrophilic and hydrophobic structural units.

[0017] Specification No. CN102911612 discloses a fluorescent EVA (ethylene vinyl acetate) adhesive film. The formulation of the fluorescent EVA adhesive film comprises EVA having a vinyl acetate content of 26 to 35% by weight, and a polymerizable fluorescent monomer (wherein the polymerizable fluorescent monomer is one or at least two of the acrylic or methacrylate salts of Eu, Y, Sm, Ce, Tb, Dy, Gd, La, and Sc, or a mixture formed by organometallic chelates of acrylic and methacrylate salts). The formulation of the fluorescent EVA adhesive film may further include additive components, namely oxide crosslinking agents, auxiliary crosslinking agents, hindered amine light stabilizers, auxiliary antioxidants, adhesives, plasticizers, and antacids; the fluorescent EVA adhesive film can not only clearly improve the packaging efficiency of components, but also greatly reduce the aging effect of ultraviolet light on photovoltaic components, and therefore the fluorescent EVA adhesive film can be widely used for packaging various photovoltaic components.

[0018] International Publication No. 2013 / 171272 describes a multilayer encapsulation film for photovoltaic modules. It discloses a polymer encapsulation layer containing a luminescence downshifting agent. Organic or inorganic luminescence downshifting agents, particularly quantum dots having an average size of less than 75 nm, are disclosed.

[0019] U.S. Patent Application Publication No. 2013 / 0075692 describes a light-emitting layer based on "quantum dots" or nanocrystalline particles dispersed in a polymer, which may be EVA, PET, PE, PP, PC, PS, PVDF, etc. Quantum dots are particles whose size is critical for light emission. The size of the particles generally varies from 2 nm to 10 nm (see Section

[0006] of U.S. Patent Application Publication No. 2013 / 0075692: 2 to 50 nm). The composite material according to the present invention does not contain quantum dot-type particles.

[0020] International Publication No. 2009 / 115435 describes submicron particles of barium magnesium aluminate that can be used in luminescent devices or as markers in translucent inks. These particles may be incorporated into a polymer matrix such as PC, PMMA, or silicone. Therefore, the same polymer as that of this application is not described in that application. The weight fraction of the particles may be 20% to 99%, i.e., a higher percentage than that assumed in the present invention. The thickness of the layer containing the particles dispersed in the polymer is 30 nm to 10 μm. Furthermore, photovoltaic applications are not mentioned at all.

[0021] French Patent No. 2993409 describes a transparent matrix containing multiple optically active components that absorb light energy at a first absorption wavelength and re-emit energy at a second wavelength greater than the first wavelength. The transparent matrix may be made from PMMA, PVC, silicone, EVA, or PVDF.

[0022] U.S. Patent No. 4,257,676 discloses a device for collecting light comprising organic or inorganic fluorescent particles exhibiting finite dipole moments having different values ​​in the ground and excited states, dispersed in an amorphous medium based on polysilicate or polyphosphate. There is no disclosure of phosphorescent materials as described in claim 1, comprising rare earth elements, zinc, or manganese. There is also no disclosure of polymers that can be extruded in the form of a film.

[0023] International Publication No. 2008 / 074869 discloses nanoparticles whose surfaces have been modified to improve the dispersibility of particles in a solvent. A person skilled in the art would not have used this document because it does not mention dispersion in polymers. The surface treatment in International Publication No. 2008 / 074869 does not mention that the particles are coated with an amphiphilic substance after the treatment is applied. Similarly, in all examples, the solutions are obtained in such a way that there is no possibility of any coating.

[0024] U.S. Patent Application Publication No. 2004 / 0166038 discloses coated luminescent particles. The coating agent is not an amphiphilic substance. There is no mention of dispersion in a polymer.

[0025] U.S. Patent No. 6,875,372 discloses phosphorescent powder. It is disclosed that phosphorescent powders can be coated. The coating agent may be a metal, a nonmetallic compound, or an organic compound such as PMMA (polymethyl methacrylate), polystyrene, or a similar organic compound including a surfactant that assists in the dispersion and / or suspension of particles in a fluid medium.

[0026] International Publication No. 2015 / 044261 discloses phosphorescent materials in polymers, but the phosphorescent particles are not modified with an amphiphilic material.

[0027] None of these documents disclose the modified phosphorescent material according to the present invention. [Overview of the project]

[0028] A first object of the present invention is a modified phosphorescent material comprising phosphorescent particles and at least one amphiphilic substance on the surface of the phosphorescent particles. The particles of the modified phosphorescent material are coated with at least one amphiphilic substance. The term "coated" means that the amphiphilic substance is on the surface of the phosphorescent particles.

[0029] According to one embodiment, all particles of the modified phosphorescent material contain an amphiphilic substance on their surface. According to another embodiment, the modified phosphorescent material contains particles that do not contain an amphiphilic substance on their surface, as well as particles that do have an amphiphilic substance on their surface. The presence of an amphiphilic substance on the surface of a particle can be determined with the help of an electron microscope coupled with an analytical microscope such as XPS (X-ray photoelectron spectroscopy; using XPS, it is possible to detect all elements except H and He).

[0030] amphiphilic substances The term "amphiphilic substance" is used herein to refer to a compound comprising at least one polar water-soluble group bonded to a water-insoluble hydrocarbon chain. The function of an amphiphilic substance is to facilitate the dispersion of modified phosphorescent particles in a polymer.

[0031] The amphiphilic material is selected so that the modified phosphorescent particles are dispersed in the polymer. "Dispersion" means that the modified phosphorescent particles can be sufficiently dispersed in the polymer. This means that most of the particles do not form aggregates in the polymer. This can be observed by electron microscopy (e.g., under 5000x magnification). For example, it has been observed that particles of modified phosphorescent MP1 (the amphiphilic material is sodium stearate) can be sufficiently dispersed in the ethylene-vinyl acetate copolymer, as seen in Figure 4. In Figure 3, it can be observed that the particles of the unmodified phosphorescent material are not sufficiently dispersed in the copolymer, and that the particles form aggregates. Therefore, the amphiphilic material can be selected for a particular phosphorescent material and a particular polymer by extruding the polymer and modified phosphorescent material to form a film, and then observing by electron microscopy whether the modified phosphorescent particles are sufficiently dispersed in the film.

[0032] Non-limiting examples of suitable amphiphilic substances include, for example, linear or branched aliphatic or aromatic acids having 10 to 50 carbon atoms and optionally possessing functional groups, whether natural or synthetic, such as aliphatic carboxylic acids, aliphatic sulfonic acids, aliphatic phosphonic acids, alkylarylsulfonic acids, and alkylarylphosphonic acids, as well as their salts and derivatives.

[0033] At least one amphiphilic substance can be selected from the group consisting of linear or branched aliphatic or aromatic carboxylic acids having 10 to 40 carbon atoms, and salts thereof. Preferred and non-limiting examples include fatty acids and salts thereof from tall oil, soybean oil, tallow oil, and linseed oil; oleic acid, linoleic acid, stearic acid and its isomers; isostearic acid, pelargonic acid, capric acid, lauric acid, myristic acid, 4-hydroxybenzoic acid, 2-ethylhexanoic acid, naphthenic acid, and hexanoic acid. The amphiphilic substance may be selected from the group consisting of fatty acids or salts of fatty acids. More particularly, the amphiphilic substance may be stearic acid or isostearic acid and its isomers. The amphiphilic substance may also be salts of stearic acid or isostearic acid and its isomers. It may be sodium or magnesium stearate or sodium or magnesium isostearate.

[0034] At least one amphiphilic substance is also a carboxylic acid having an ether linkage in the hydrocarbon chain, for example, formula R-(CH2CO) n The group may be selected from those consisting of -COOH (where R is an alkyl group having 1 to 6 carbon atoms). An example of a compound of this class is, for example, H3CO-CH2-(CH2CO)-CH2-(CH2CO)-CH2-COOH.

[0035] At least one amphiphilic substance contains CF2 units in its chain, for example, formula R-(CF2) m The formula may also include additional partially fluorinated carboxylic acids of the form -COOH (wherein R is as defined above, and m is included in 10-18).

[0036] Other suitable acids besides carboxylic acids may include dodecylbenzenesulfonic acid, toluenesulfonic acid, toluenephosphonic acid, laurylsulfonic acid, laurylphosphonic acid, palmitylsulfonic acid, and palmitylphosphonic acid.

[0037] In the context of the present invention, at least one amphiphilic substance is defined by formula (1): Polyoxyethylene alkyl ether phosphate Or equation (2): Polyoxyethylene-derived dialkyl phosphates You can also choose from the following: During the ceremony: In formula (1), R1 is a linear or branched alkyl group having 2 to 20 carbon atoms, a phenyl group, an alkylaryl group, more particularly an alkylphenyl group having an alkyl chain having 8 to 12 carbon atoms, or an arylalkyl group, more particularly a phenylaryl group; n represents the number of ethylene oxide units, which can be 0 to 12; and M represents hydrogen, sodium, or potassium. Preferably, R1 is a hexyl, octyl, decyl, dodecyl, oleyl, or nonylphenyl group; In formula (2), R2 and R3 may be the same or different, and are selected from a linear or branched alkyl group having 2 to 20 carbon atoms, a phenyl group, an alkylaryl group, more particularly an alkylphenyl group having an alkyl chain having 8 to 12 carbon atoms, or an arylalkyl group, more particularly a phenylaryl group; n may be 0 to 12, representing the number of ethylene oxide units; and M represents hydrogen, sodium, or potassium. Preferably, R2 and R3 are independently hexyl, octyl, decyl, dodecyl, oleyl, or nonylphenyl groups.

[0038] Notable examples of this type of amphiphilic substance include polyoxyethylene alkyl ether phosphates (where the alkyl ether portion has 8 to 10 carbon atoms); polyoxyethylene tridecyl ether phosphates; polyoxyethylene oleodecyl ether phosphates; polyoxyethylene nonylphenyl ether phosphates; and polyoxyethylene nonyl ether phosphates.

[0039] At least one amphiphilic substance is given by formula (3): R4-(OC2H4) pThe group can be selected from the group consisting of polyoxyethylene-derived alkyl ether carboxylates of -O-R5 (wherein R4 is a linear or branched alkyl group that may have 4 to 20 carbon atoms in particular; p is an integer from 1 to 20, typically 2 to 16, preferably 3 to 12; and R5 is a carboxylic acid residue, e.g., -CH2COOH).

[0040] In an advantageous embodiment of the present invention, at least one amphiphilic substance is selected from the group consisting of linear or branched aliphatic carboxylic acids having 10 to 40 carbon atoms, preferably 10 to 30 carbon atoms, more preferably 12 to 25 carbon atoms, and even more preferably 14 to 20 carbon atoms, and salts thereof.

[0041] In a particularly advantageous embodiment, at least one amphiphilic substance is selected from the group consisting of stearic acid, its isomers, and salts thereof, such as alkali metal salts. It may be stearic acid or isostearic acid, its isomers, and salts thereof. It may be sodium or magnesium stearate or sodium or magnesium isostearate.

[0042] According to one embodiment, the amphiphilic substance is not a water-insoluble polymer dispersant, in particular a water-insoluble dispersant having hydrophilic and hydrophobic structural units, obtained by polymerizing at least one vinyl compound.

[0043] The modified phosphorescent material typically contains at least 0.1% by weight, preferably at least 0.5% by weight, and more preferably at least 0.7% by weight of at least one amphiphilic substance relative to the total weight of the phosphorescent particles (i.e., the amount of amphiphilic substance is 0.1 parts, preferably at least 0.5 parts, and more preferably at least 0.7 parts per 100 parts of modified phosphorescent particles). The amount of at least one amphiphilic substance coated on the phosphorescent particles is generally not more than 10.0% by weight, more typically not more than 7.0% by weight, and preferably not more than 5.0% by weight, relative to the total weight of the phosphorescent particles.

[0044] Phosphorescent material Any type of inorganic phosphorescent material may be used to prepare the modified phosphorescent material of the present invention. In particular, an inorganic phosphorescent material suitable for the present invention contains at least one element selected from the group consisting of rare earth elements, zinc, and manganese.

[0045] Advantageously, the phosphorescent material contains at least one element selected from the group consisting of rare earth elements, zinc, and manganese, and • External quantum yield of 40% or more across excitation wavelengths in the 350nm to 440nm range; • Absorption of less than 15% at wavelengths above 440 nm; and • Maximum value of the emission spectrum in the wavelength range of 440nm to 900nm A phosphorescent material is selected from among those having the following properties.

[0046] The phosphorescent material typically has an external quantum yield of at least 40%, preferably at least 50%, over excitation wavelengths included in the range of 350 nm to 440 nm.

[0047] Phosphorescent materials absorb well in UV light and absorb little to no visible light (440-700 nm). Phosphorescent materials have an absorption of 15% or less, typically less than 10%, preferably less than 5%, and more preferably less than 3% at wavelengths above 440 nm.

[0048] The maximum emission spectrum of the phosphorescent material is in the wavelength range of 440 nm to 900 nm, preferably 500 nm to 900 nm.

[0049] The optical properties of a modified phosphorus are not altered by the presence of at least one amphiphilic material coated on the phosphorus particles. Therefore, a modified phosphorus is characterized by the same external quantum yield, absorption and emission properties as its original phosphorus, and more generally, by the same optical properties.

[0050] The phosphorescent material can be selected from the group consisting of aluminates doped with at least one rare earth element and / or manganese. A suitable aluminate is formula (Ia) or formula (Ib): A 1 MgAl 10 O 17 :EU 2+ (Ia) A 1 MgAl 10 O 17 :EU 2+ ,Mn 2+ (Ib) (In the formula, A 1 (This represents at least one of Ba, Sr, or Ca, either alone or in combination.) It belongs to them.

[0051] Expression throughout the text: "A 1 MgAl 10 O 17 :EU 2+ " and its analogues are used herein to refer to europium-doped magnesium aluminate compounds. A typical example of an aluminate is, for example, BaMgAl 10 O 17 :EU 2+ and BaMgAl 10 O 17 :EU 2+ ,Mn 2+ That is the case.

[0052] An alternative aluminate is given by formula (II): a(M 1-d M 1 d O).b(Mg 1-e M 2 e O).c(Al2O3) (II) (In the formula, M is at least one element selected from Ba, Sr, and Ca; ·M 1 This represents a rare earth element, preferably at least one of Gd, Tb, Y, Yb, Eu, Nd, or Dy, more preferably Eu; ·M 2 (where is at least one of Zn, Mn, or Co, preferably Mn; a, b, c, d, and e satisfy the following relationships: 0.25 ≤ a ≤ 2.00; 0 ≤ b ≤ 2.00; 3.00 ≤ c ≤ 9.00; 0 ≤ d ≤ 0.40 and 0 ≤ e ≤ 0.60) It may also be something else.

[0053] Preferably, the aluminate is of formula (IIa): a(M 1-d EU d O).b(Mg 1-e Mn e O).c(Al2O3) (IIa) (wherein M, a, b, c, d, and e are as defined above); Or formula (IIb): a(Ba 1-d M 1 d O).b(Mg 1-e M 2 e O).c(Al2O3) (IIb) (In the formula: M 1 As defined above, is preferably Eu; M 2 (a, b, c, d, and e are as defined above.) It will be selected from the following.

[0054] More preferably, the phosphor is an aluminate selected from those of formula (IIb). In particular, the aluminate may satisfy the above formula (IIb) where a = b = 1.00 and c = 5.00. Alternatively, the phosphor may satisfy the above formula (IIb) where a = b = 1.00 and c = 7.00. Further alternatively, the phosphor may satisfy the above formula (IIb) where a = 1.00; b = 2.00 and c = 8.00. According to another embodiment, e = 0. According to another embodiment, d = 0.1. According to another embodiment, 0.09 ≦ d ≦ 0.11. The aluminate may be from Example 1.

[0055] Notable examples that may be mentioned of suitable aluminates are of the formula: BaMgAl 10 O 17 ; Ba 0.9 Eu 0.1 MgAl 10 O 17 ; Ba 0.9 Eu 0.1 Mg 0.6 Mn 0.4 Al 10 O 17 ; Ba 0.9 Eu 0.1 Mg 0.8 Mn 0.2 Al 10 O 17 ; Ba 0.9 Eu 0.1 Mg 0.95 Mn 0.05 Al 10 O 17 ; BaMgAl 14 O 23 ; Ba 0.9 Eu 0.1 MgAl 14 O 23 ; Ba 0.8 Eu 0.2 Mg 1.93 Mn 0.07 Al 16 O 27 and the like.

[0056] The average particle size d, which is included in the range of 80 nm to 300 nm, preferably 80 nm to 200 nm, and more preferably 100 nm to 200 nm, is determined by laser diffraction technique using a laser particle size analyzer (volume distribution). 50 Aluminates having the above-described details can be prepared in accordance with International Publication No. 2009 / 115435.

[0057] The constituent particles of the aluminate prepared according to the teachings of International Publication No. 2009 / 115435 are of the properties of their single crystals. As a result of these single-crystal properties, the aluminate particles of the present invention are well-separated, individual forms. There is little to no particle clumping. This good individualization of the particles is measured by laser diffraction techniques. 50 This may be demonstrated by comparing it with measurements taken from images obtained by a transmission electron microscope (TEM). A transmission electron microscope that allows for close-up magnification up to 800,000 may be used. The principle of this method is to examine various regions (approximately 10) under the microscope and measure the dimensions of 250 particles deposited on a support (e.g., after depositing a suspension of particles on a support and allowing the solvent to stand and evaporate), taking into account that these particles are spherical. A particle is considered identifiable if at least half of its circumference can be defined. The TEM value corresponds to the diameter of a circle that accurately reproduces the outer circumference of the particle. Identification of usable particles can be done using ImageJ, Adobe Photoshop, or Analysis software. After measuring the particle size by the above method, the cumulative particle size distribution of the particles is estimated therefrom, which is regrouped into several particle size categories in the range of 0 to 500 nm, with a width of 10 nm for each category. The number of particles in each category is the basic data for representing the particle size distribution by number. The TEM value is the median diameter such that 50% (depending on the number) of the particles counted on the TEM image have a diameter smaller than this value. Here again, the values ​​obtained by these two techniques are of the same order of magnitude (d 50The ratio (value / TEM value), therefore, this ratio is less than 2, and especially more than 1.5.

[0058] Phosphorescents also include europium dopurine, for example, formula (III):A 2 BPO4:Eu 2+ (In the formula, A 2 (where B is selected from the group consisting of phosphates of Li, Na, and K, either alone or in combination, and B is selected from the group consisting of phosphates of Ba, Sr, and Ca, either alone or in combination. A non-limiting example of this type of phosphate is LiCaPO4:Eu 2+ and LiBaPO4:Eu 2+ That is the case.

[0059] The phosphorescent material is given by formula (IV): La x Ce y Tb z The rare earth phosphates of PO4 (wherein x, y, and z are such that the sum of x+y+z is equal to 1, and at least one of y and z is not equal to 0) may be selected.

[0060] If at least one of x and y is non-zero in equation (IV), preferably z is at most 0.50; z may be between 0.05 and 0.20, more particularly between 0.10 and 0.20; x may be more particularly between 0.40 and 0.95.

[0061] The following phosphates may be mentioned as examples: La 0.44 Ce 0.43 Tb 0.13 PO4, La 0.57 Ce 0.29 Tb 0.14 PO4, La 0.56 Ce 0.30 Tb 0.14 PO4, La 0.94 Ce 0.06 PO4, Ce 0.67 Tb 0.33 PO4. Phosphorescents are also known as europium-doped halophosphates, for example, formula (V):A 35(PO4)3X:Eu 2+ (In the formula, A 3 (where is selected from among Ba, Sr, and Ca, either alone or in combination, and X is OH, F, or Cl). A suitable example of a halophosphate is Sr5(PO4)3Cl:Eu 2+ and Ca5(PO4)3Cl:Eu 2+ That is the case.

[0062] Europium and / or manganese-doped silicates can also be suitably used as phosphorescent materials in the present invention.

[0063] These silicates are given by the following general formulas (VIa) to (VIi): A 4 MgSiO4(VIa) A 4 MgSiO4:Eu 2+ (VIb) A 4 MgSiO4:Eu 2+ ,Mn 2+ (VIc) A 4 3MgSi2O8(VId) A 4 3MgSi2O8:Eu 2+ (VIe) A 4 3MgSi2O8:Eu 2+ ,Mn 2+ (VIf) A 4 2MgSi2O7(VIg) A 4 2MgSi2O7:Eu 2+ (VIh) A 4 2MgSi2O7:Eu 2+ ,Mn 2+ (VIi) (In the formula, A 4 (This may have at least one selected from Ba, Sr, and Ca.)

[0064] Examples of suitable silicates are provided in Table 1.

[0065]

[0066] Among the silicates, the compounds disclosed in International Publication No. WO 2004 / 044090 pamphlet may be mentioned. Preferred compounds are of formula (VIj): Ba 3(1-x) Eu 3x Mg 1-y Mn y Si2O8(VIj) (where x and y are characterized by the following relationships: 0 < x ≤ 1.0; 0 < y ≤ 0.3 and x + y ≤ 1.2). More particularly, x and y satisfy the following relationships: 0.0001 ≤ x ≤ 0.25 and 0.0001 ≤ y ≤ 0.25; or 0.01 ≤ x ≤ 0.25 and 0.01 ≤ y ≤ 0.25).

[0067] Cerium-doped rare earth borates or silicates may also be used as the phosphors of the present invention.

[0068] Preferred borates typically have the general formula (VII): LnBO3:Ce 3+ or LnBO3:Ce 3+ ,Tb 3+ or LnBO3:Eu 3+ (where Ln is at least one of La, Gd, Y, Lu), for example, YBO3:Eu 3+ is suitable.

[0069] Preferred silicates typically have the general formula (VIII): Ln2SiO5:Ce 3+ (where Ln is at least one of La, Gd, Y, Lu) is suitable. Additionally, preferred phosphors may be selected from rare earth oxy-sulfides of formula (IX): Ln2O2S:Eu 3+ (where Ln represents La, Gd, Y, Lu). A notable example of such a phosphor is La2O2S:Eu 3+ is.

[0070] Rare earth vanadates of formula (Xa) or formula (Xb) may also be used as the phosphors of the present invention. LnVO4:Eu 3+ ,Bi3+ (Xa), Ln'PVO4(Xb) (wherein Ln is at least one of La, Gd, Y, and Lu, and Ln' is at least one rare earth element). A suitable example of such a phosphorescent material is, for example, YVO4:Eu 3+ ,Bi 3+ That is the case.

[0071] Additional suitable phosphorescent materials may be selected from the group consisting of manganese, zinc, silver, and / or copper-doped zinc compounds. A notable example is ZnS:Mn 2+ The components are ZnS:Ag,Cu and ZnO:Zn.

[0072] The phosphorescent materials described in detail above can be prepared by known means. All the preferences for the chemical properties of the phosphorescent materials described in detail above apply equally to the modified phosphorescent materials of the present invention.

[0073] The phosphorescent material of this invention is in the form of particles. The phosphorescent material is characterized by a specific size and size distribution. The phosphorescent particles typically have an average diameter d of less than 1.00 μm. 50 Characterized by the average particle diameter d. 50 The average diameter d is typically at most 0.80 μm, preferably at most 0.60 μm, and more preferably at most 0.50 μm. 50 In some cases, the average particle diameter d may be as small as 0.50 μm. 50 These particles are typically at least 0.01 μm, preferably at least 0.05 μm, more preferably at least 0.10 μm, and even more preferably at least 0.20 μm.

[0074] Typically, phosphorescent particles have a narrow particle size distribution, and more precisely, their distribution index may be at most 1.0, preferably at most 0.7, and more preferably at most 0.5.

[0075] Phosphorescent particles have an average particle diameter d less than 1.00 μm and typically at least 0.01 μm, more particularly less than 0.80 μm and at least 0.20 μm. 50 You may also indicate this.

[0076] To promote good dispersion in the polymer and reduce film haze, it is important to control the size and distribution of the modified phosphors. The size and size distribution properties of the phosphors are equally applicable to the modified phosphors. Such properties are measured by laser diffraction techniques (volume distribution) in a suitable solvent (see definition). For example, in the case of the modified phosphor MP1, a suitable solvent in which the particles do not settle and remain in the suspension may be an isoparaffinic solvent such as Isopar®.

[0077] In an advantageous embodiment of the present invention, the modified phosphorescent material is • Average particle diameter d less than 1.00 μm and typically at least 0.01 μm; more particularly, less than 0.80 μm and at least 0.20 μm. 50 ; • External quantum yield of 40% or more across excitation wavelengths in the 350nm to 440nm range; • Absorption of less than 15% at wavelengths above 440 nm; and It is characterized by the maximum value of the emission spectrum in the wavelength range of 440 nm to 900 nm.

[0078] The modified phosphorescent material is typically in the form of solid particles, and the particles have the size and size distribution defined above. A liquid composition containing the modified phosphorescent material and a liquid medium may be obtained by dispersing the modified phosphorescent material in a suitable liquid.

[0079] Preparation of modified phosphorescent material The modified phosphorescent material of the present invention may be prepared by any suitable method typically used for coating inorganic particles. An applicable method is disclosed in Example 1 ("Preparation of Modified Phosphorescent Material MP1").

[0080] According to a first embodiment of the present invention, a modified phosphorescent material may be prepared by adding at least one amphiphilic substance to dry phosphorescent particles. Mixing apparatus available for mixing dry phosphorescent particles with a liquid containing the amphiphilic substance is known to those skilled in the art. If at least one amphiphilic substance is a liquid, the addition can be made using a pure amphiphilic substance or a liquid composition containing the amphiphilic substance and a suitable solvent. If the amphiphilic substance is a solid, it is preferable to dissolve the solid in a suitable solvent before adding it to the phosphorescent particles. The solvent is typically selected from among solvents that can dissolve the amphiphilic substance, can be easily removed from the final product at the end of the coating process, and do not dissolve the phosphorescent particles. If the amphiphilic substance is a solid, it is also possible to use dispersion of fine particles of the amphiphilic substance in a solvent that can be easily removed from the final product at the end of the coating process and does not dissolve the phosphorescent particles.

[0081] According to another embodiment of the present invention, a modified phosphorescent material may be prepared by a method comprising: providing a composition of phosphorescent particles in a liquid medium; adding at least one amphiphilic substance to the composition; and removing the liquid medium and drying it. Mixing can be performed using a cross-blade impeller.

[0082] The liquid medium is typically selected based on the properties of phosphorescent particles and at least one amphiphilic substance, using capabilities well known to those skilled in the art.

[0083] In an advantageous embodiment of this method, at least one amphiphilic substance is added to the composition of phosphorescent particles in a liquid medium during a wet grinding step performed to obtain a desired particle size of phosphorescent particles. The wet grinding step is generally carried out in water, or a water / solvent mixture or an organic solvent. The wet grinding is carried out under conditions well known to those skilled in the art.

[0084] At least one amphiphilic substance is added to the phosphorescent material during the wet grinding process by adding an appropriate amount of the at least one amphiphilic substance to the pulverized phosphorescent material. The at least one amphiphilic substance may be added as is, in solid form (e.g., using sodium stearate), in liquid form (e.g., isostearic acid), or as a solution in a suitable solvent as defined above. Therefore, the selection of the solvent for the wet grinding process is made considering the compatibility of the solvent with both the phosphorescent material and the at least one amphiphilic substance.

[0085] The amphiphilic substance may be added gradually to ensure that all phosphorescent particles are coated with the amphiphilic substance.

[0086] At the end of the process of mixing the phosphorescent material and the amphiphilic substance, the mixture is dried to remove any traces of solvent or water that may have been used. The duration and temperature required to remove any traces of solvent or water depend on the type of solvent used and the type of amphiphilic substance used.

[0087] Composition comprising modified phosphorescent material and polymer The modified phosphorescent material of the present invention has been found to be able to be incorporated into a polymer to provide an article that advantageously has luminescent properties and better transparency than prior art articles. Better transparency is achieved by good dispersion of the modified phosphorescent material particles in the polymer.

[0088] Accordingly, a further object of the present invention is a composition comprising the modified phosphorescent material and polymer of the present invention. Accordingly, the present invention also relates to a composition comprising phosphorescent material particles having at least one amphiphilic substance on its surface, dispersed in at least one polymer. The phosphorescent material is as disclosed above in all disclosed embodiments and variations. The amphiphilic substance is as disclosed above in all disclosed embodiments and variations.

[0089] The properties of the polymers in the composition are not particularly limited. According to one embodiment, the polymer (or mixture of polymers) is adapted to be extruded in the form of a film.

[0090] The polymer (Pol1) may be selected from the group consisting of alpha-olefin homo- and copolymers, polycondensation polymers, such as polyamides, polyesters, polycarbonates, and polyacrylates, and halogenated polymers, such as chlorinated and fluorinated polymers.

[0091] Examples of alpha-olefin homopolymers and copolymers include ethylene homopolymer, propylene homopolymer, ethylene / propylene copolymer, ethylene / 1-butene copolymer, ethylene / 1-hexene copolymer, ethylene / 1-octene copolymer, propylene / 1-octene copolymer, ethylene / vinyl acetate copolymer, ethylene / (meth)acrylic acid copolymer, and neutralized ethylene / (meth)acrylic acid copolymer.

[0092] Suitable alpha-olefin homo- and copolymers may be functionalized, for example, by grafting a non-functionalized polymer with one or more ethylene-based unsaturated monomers having at least one functional group. Suitable grafting agents include, for example, acrylonitrile, methacrylonitrile, methyl vinyl ketone, unsaturated dicarboxylic acids, their esters, and their anhydrides, such as maleic anhydride; acrylic acid and / or methacrylic acid, and their esters.

[0093] Among suitable polyesters, there may be polyesters containing repeating units derived from ethylene glycol and phthalic acid, such as terephthalic acid or isophthalic acid.

[0094] Among halogenated polymers, fluorinated polymers, particularly polymers containing repeating units derived from at least one ethylenically unsaturated fluorinated monomer, may be mentioned. Non-limiting examples of suitable ethylenically unsaturated fluorinated monomers are: C2-C8 fluorofluoroolefins such as tetrafluoroethylene, hexafluoropropylene, pentafluoropropylene, and hexafluoroisobutylene; C2-C8 hydrogenated fluoroolefins such as vinyl fluoride, 1,2-difluoroethylene, vinylidene fluoride, and trifluoroethylene; ·Formula CH2=CH-R f0 (In the formula, R f0 Fluoroalkylethylenes (which are C1-C6 fluoroalkyls or C1-C6 fluorooxyalkyls having one or more ether groups); Chlorotrifluoroethylene and other chloro- and / or bromo- and / or iodo-C2 to C6 fluoroolefins; ·Formula CF2=CFOR f1 (In the formula, R f1 Fluoroalkyl vinyl ethers (which are C1-C6 fluoroalkyls, e.g., -CF3, -C2F5, -C3F7) That is the case.

[0095] Notable examples of suitable fluorinated polymers include polyvinylidene fluoride polymers, ethylene / chlorotrifluoroethylene copolymers, and ethylene / tetrafluoroethylene copolymers.

[0096] Among alpha-olefin copolymers, copolymers containing copolymer units of ethylene and at least one vinyl carboxylate ester may be mentioned. Examples of vinyl carboxylate esters include vinyl acetate, vinyl versatate, vinyl propionate, vinyl butyrate, or vinyl maleate. Vinyl acetate is preferred. The copolymer may contain units of ethylene and vinyl acetate only. The copolymer may contain 5 to 40% by weight of vinyl carboxylate and 60 to 95% by weight of ethylene as monomers. More particularly, the copolymer may contain 10 to 35% by weight of vinyl carboxylate and 65 to 90% by weight of ethylene as monomers. Most preferably for a good balance of optical and mechanical properties, the copolymer may contain 25 to 35% by weight of vinyl carboxylate and 65 to 75% by weight of ethylene as monomers.

[0097] The copolymer may have a melt flow rate (MFR) in the range of 0.1 to 300 g / 10 min (ASTM D 1238 at 190°C / 2.16 kg), and more particularly, in the range of 0.5 to 50 g / 10 min. An example of an EVA copolymer may be the EVA of Example 2, or EVA having 33 wt% vinyl acetate and an MFR of 45 g / 10 min.

[0098] If the composition is based on a copolymer of ethylene and at least one vinyl carboxylate ester, it may further contain at least one organic peroxide as a crosslinking agent that enables the copolymer to be crosslinked. If the composition is in the form of a film, crosslinking allows for increased adhesive strength, moisture resistance, and penetration resistance of the film while maintaining high transparency. Thus, the term “polymer” also encompasses “crosslinked polymer.”

[0099] Organic peroxides decompose preferably at a temperature of at least 110°C. The peroxides and their amounts are selected so as not to significantly alter the processing conditions of the copolymer. For example, when the copolymer is extruded, the peroxides and their amounts are selected so as not to significantly alter the extrusion conditions (zone temperature, extruder properties, rotation speed, etc.) compared to the conditions used for extrusion of copolymers without crosslinking agents. Examples of organic peroxides include 2,5-dimethylhexane-2,5-dihydroperoxide, 2,5-dimethyl-2,5-di-tert-butylperoxy)hexane, 3-di-tert-butylperoxide, dicumylperoxide, 2,5-dimethyl-2,5-di(2-ethylhexanoylperoxy)hexane, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, tert-butylcumylperoxide, (alpha),(alpha)'-bis(tert-butylperoxyisopropyl)benzene, (alpha) Examples include (alpha)'-bis-tert-butylperoxy)diisopropylbenzene, n-butyl-4,4-bis(tert-butylperoxy)butane, 2,2-bis-tert-butylperoxy)butane, 1,1-bis(tert-butylperoxy)cyclohexane, 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, tert-butylperoxybenzoate, benzoyl peroxide, and 1,1-di(tert-hexylperoxy)-3,3,5-trimethylcyclohexane.

[0100] 2,5-dimethyl-2,5-di(2-ethylhexanoylperoxy)hexane and 1,1-di(tert-hexylperoxy)-3,3,5-trimethylcyclohexane may be specifically mentioned. Tert-butylperoxy 2-ethylhexyl carbonate or 2,5-di-methyl-2,5-di(tert-butylperoxy)hexane may also be mentioned, as these peroxides enable high crosslinking of EVA.

[0101] The content of the organic peroxide in the composition may be in the range of 0.1 to 5 parts by weight, more particularly 0.2 to 1.8 parts by weight, based on 100 parts by weight of the copolymer. The composition may further contain at least one crosslinking aid that provides at least one polymerizable functional group. The content of the crosslinking aid is typically in the range of 0.1 to 5.0 parts by weight, based on 100 parts by weight of the copolymer. Examples of aids include trifunctional crosslinking agents, such as triallyl cyanurate and triallyl isocyanurate, and monofunctional and bifunctional crosslinking aids of (meth)acrylic acid esters. Among these compounds, triallyl cyanurate and triallyl isocyanurate are preferred.

[0102] Those skilled in the art know how to adapt the properties and content of organic peroxides and crosslinking aids to copolymers. In particular, the following documents may be cited: Solar Energy Materials & Solar Cells 2013, 116, 203-218 and International Publication No. 2013 / 171272. Specifically, those skilled in the art select organic peroxides such that their half-life temperature is suitable for the extrusion temperature. The extrusion temperature depends to a considerable extent on the properties of the extruded polymer. The content of the organic peroxides is also selected so that extrusion is still possible and the final extruded film maintains the correct balance of mechanical and optical properties.

[0103] The composition may also further contain other additives known in the art for modifying copolymers for photovoltaic modules. For example, the composition may also contain at least one silane coupling agent to improve the adhesive strength of the composition.

[0104] The composition typically contains at least 0.05% by weight, preferably at least 0.10% by weight, and more preferably at least 0.20% by weight, of the total weight of the composition, of the modified phosphorescent material. The amount of modified phosphorescent material is typically at most 10.00% by weight, preferably at most 7.00% by weight, and more preferably at most 5.00% by weight, of the total weight of the composition. Favorable results were obtained when the modified phosphorescent material was present in an amount of 0.10 to 5.00% by weight, preferably at most 0.20 to 2.00% by weight, of the total weight of the composition. The amount of modified phosphorescent material in the composition is determined so that the film made from the composition exhibits the desired luminescent properties and good transparency.

[0105] According to a specific embodiment, the composition comprises a modified phosphorescent material and at least one polymer, where, The phosphorescent material is an aluminate as described above; • At least the amphiphilic substances are stearic acid or isostearic acid, their isomers, and their salts; The polymer is a copolymer comprising copolymer units of ethylene and at least one vinyl carboxylate ester, as described above. The copolymer may or may not be crosslinked. The copolymer may contain only ethylene and vinyl acetate units.

[0106] The composition may be prepared using any prior art known in the art. For example, mixing can be carried out using any mixing apparatus known to be useful for preparing polymer compositions, including roller-type rubber mills, Banbury mixers, twin-screw extruders, etc. Mixing may be carried out by the techniques disclosed in the examples for the preparation of MP1.

[0107] In one embodiment, the polymer (Pol1) is mixed with a phosphorescent material for the preparation of the composition.

[0108] In another embodiment, the polymer (Pol1) described above is mixed with a masterbatch containing a phosphorescent material for the preparation of a composition. In this case, polymer (Pol1) is mixed with a masterbatch containing a phosphorescent material predispersed in polymer (Pol2). Polymer (Pol2) may be of the same type as polymer (Pol1), or it may be different. The two polymers (Pol1) and polymer (Pol2) are preferably compatible to form a homogeneous mixture. For example, if (Pol1) is an ethylene-vinyl acetate copolymer, Pol2 may be the same ethylene-vinyl acetate copolymer or a different one, or Pol2 may also be a compatible polymer, such as polyethylene. The masterbatch is prepared by the same prior art described above, for example, it may be prepared using an extruder. The advantage of using a masterbatch is that the particles can be sufficiently predispersed using a mixing apparatus exhibiting a high shear rate. Various additives (for example, the crosslinking agents and auxiliary agents listed above) may be present in Pol1 or Pol2, or added separately.

[0109] The present invention also relates to a method for preparing a composite material according to the present invention, wherein a masterbatch comprising polymer Pol1 and a modified phosphorescent material, or polymer Pol1 and a phosphorescent material pre-dispersed in polymer Pol2, is extruded.

[0110] Articles made from the composition A further object of the present invention is an article comprising the composition of the present invention.

[0111] In one embodiment of the present invention, the article is in the form of a film or sheet. The film or sheet may have a thickness of 15 to 800 μm, preferably 20 to 600 μm, and more preferably 25 to 500 μm. The thickness may be determined by a micrometer. The thickness is the arithmetic mean thickness of 20 random measurements taken on the film at 25°C.

[0112] Film manufacturing techniques are well known in the art. The compositions of the present invention are preferably processed in the form of a film by cast extrusion or hot blown extrusion techniques, with optional uniaxial or biaxial stretching. Techniques particularly suited to the production of films of the compositions of the present invention involve extruding a molten composition through an elongated die to obtain an extruded tape, and casting / rolling the extruded tape to obtain a film. The tape can be rolled into a film by passing it through a suitable roll, the roll can be maintained at a suitable temperature, and its speed can be adjusted to achieve the required thickness. The thickness of the film is controlled by the die.

[0113] The film obtained from the composition of the present invention is preferably a transparent film, that is, the film has a total transmittance of more than 80%, preferably more than 90%, when determined to be a film with a thickness of about 450 μm according to the method detailed below.

[0114] Furthermore, films obtained from the compositions of the present invention are preferably such that, in terms of transmittance, light scattering, which causes a reduction in the contrast of images seen through them, is limited. In other words, films obtained from the compositions of the present invention have a haze value (as defined below) of less than 35%, preferably less than 30%, when determined for a film having a thickness of about 450 μm.

[0115] The film obtained in this manner is another object of the present invention.

[0116] The film of the present invention can be advantageously assembled into a multilayer structure. A multilayer structure containing the film of the present invention is also an object of the present invention.

[0117] Use of film The film of the present invention is particularly suitable for use in photovoltaic modules for greenhouses. The photovoltaic module includes solar cells made from crystalline silicon. The solar cells may be second-generation solar cells known as "thin-film" solar cells, which are based on amorphous silicon, cadmium telluride (CdTe), or copper indium gallium selenide (CIGS) and their analogues, or third-generation cells such as organic photovoltaic (OPV) systems and dye-sensitized solar cells (DSSC).

[0118] Another aspect of the present invention is a photovoltaic module comprising the composition of the present invention in the form of a film or layer. Once fixed, the film or layer allows for an increase in the absolute efficiency of the active element of a solar cell in converting light energy into electrical energy. It allows for the conversion of UV rays into visible rays absorbed by the active element, thereby increasing the number of photons that can be used.

[0119] The composition, in the form of a film or layer, may be located directly in front of the active elements of the cell, for example, as a encapsulant for these elements, or as a layer deposited in place of or on the glass of the cell. The active elements of the cell are elements that convert light energy into electricity.

[0120] Therefore, the present invention also relates to the use of a composition in the form of a film or layer to increase the efficiency of converting light energy to electrical energy in a photovoltaic cell.

[0121] The present invention also relates to a method for converting light energy into electrical energy using a photovoltaic cell, which involves increasing the number of photons that can be used by an active element for the conversion of light energy into electricity, with the help of a composition in the form of a film or layer.

[0122] The present invention will be described in more detail below in relation to the following embodiments, but the embodiments are for illustrative purposes only. If any disclosure in any patent, patent application, or publication incorporated herein by reference is inconsistent with the description of this application to such an extent that it obscures the terminology, the description herein shall prevail. [Examples]

[0123] Example 1: Preparation of modified phosphorescent MP1 In the wet grinding process, without adding any dispersant, according to Example 1 of International Publication No. 2009 / 115435 A1, Ba 0.9 EU 0.1 MgAl 10 O 17 An aqueous suspension was prepared. The grinding process was carried out using a pilot wet grinder Labstar (NETSZCH®) with the following parameters.

[0124]

[0125] After 150 minutes of grinding, the average particle diameter of the phosphorescent material was d 50 It was found to be 290 nm (measured as a diluted dispersion in water). This was measured using a Malvern Nanosizer.

[0126] 6 g of sodium stearate was added to the suspension under stirring for 1 hour using a four-blade cross impeller (6 g of stearate and 234 g of phosphorescent Ba 0.9 EU 0.1 MgAl 10 O 17 (This corresponds to 2.5% by weight of sodium stearate). After mixing, the suspension was then dried overnight in an oven at 100°C to obtain modified phosphorescent MP1. The absorption and emission spectra of modified phosphorescent MP1 are reported in Figures 1 and 2.

[0127] A reference phosphorescent sample (P1) was prepared using the same procedure without adding any amphiphilic substances during the wet grinding process.

[0128] Example 2: Preparation of compositions using MP1 and P1 A polymer composition containing 90% by weight of ethylene / vinyl acetate copolymer (Elvax® 150, commercially available from DuPont containing 32% by weight of vinyl acetate; melt flow rate at 43 g / 190 / 10 / 2.16 kg) and 10% by weight of modified phosphorescent MP1 was prepared using a co-rotating twin-screw extruder type Prism 25D (diameter 16 mm and L / D ratio 25; screw profile: PR25.5).

[0129] The ethylene / vinyl acetate copolymer and MP1 pellets were pre-mixed in a rotary mixer for 10 minutes and then introduced into an extruder under the following operating conditions: Table 3. In this way, the masterbatch MB1 was obtained in pellet form.

[0130]

[0131] A similar composition (comparative MB1) was prepared using the reference phosphorescent material P1 (unmodified).

[0132] Example 3: Film Preparation The 402g masterbatch obtained earlier was mixed with 7650g of pure Elvax® 150 (corresponding to a 0.5 wt% phosphorescent load in the final composition) in a rotary blender for 10 minutes and then extruded using a co-rotating twin-screw extruder Leistritz LMM 30 / 34 (34mm diameter and L / D ratio 25, screw profile: L16 without degassing) equipped with slot dies (300mm width and 450-500 microns thickness). Extrusion parameters are reported in Table 4.

[0133]

[0134] The resulting film had a thickness of 450 μm.

[0135] These optical properties were measured using a UV-VIS spectrometer Lambda 900 Perkin Elmer. Total transmittance was measured over the range of 450–800 nm and normalized to 0–100%.

[0136] Haze was determined using the same instrument following the procedure below: Total transmittance was recorded from 450 to 800 nm (step 1 nm). Diffuse transmittance was recorded from 450 to 800 nm (step 1 nm). [The haze at 524nm was determined according to the following relationship: % Haze 524nm =Total transmittance (%) 524nm / diffusive transmittance 524nm ]

[0137] The photoluminescence yields of the present invention film and the comparative film under UV 370 nm excitation were determined using a HORIBA JOBIN YVON fluoromax 3 luminescence spectrometer equipped with a film element oriented at 30°. Film samples were fixed onto the film element, and luminescence spectra were recorded from 390 nm to 650 nm under an excitation wavelength of 370 nm.

[0138] The value measured for the film of the present invention was set as 100% photoluminescence yield.

[0139]

[0140] The data in Table 5 demonstrate that the modified phosphorescent material of the present invention provides articles with lower haze and higher light transmittance than films obtained with prior art phosphorescent materials. Figures 3 and 4 allow for a comparison of the dispersion of particles in the same polymer for the unmodified and modified phosphorescent materials, respectively.

[0141] The film also exhibits a higher photoluminescence yield compared to films obtained using the same phosphorescent material that does not have an amphiphilic substance on its surface.

[0142] Example 4: Preparation of a photovoltaic module p-type cells were tested using monocrystalline or polycrystalline silicon: Solland solar cells (bare cell efficiency 16%) or Photowatt cells (bare cell efficiency 20%).

[0143] Prepare the module in the following way: - Applying electrically connected Ag-cap Cu to semiconductors; - The stack is prepared by continuously applying its contacts to the backsheet (PVDF-based), back encapsulant (EVA type), and semiconductor; Next, add the film of the present invention (width 30 cm; thickness 500 μm) as a front sealing material; - Add glass to the front seats.

[0144] Immediately after preparation, the stack is processed through a hot press lamination process (120 / 30 min) to induce crosslinking and allow the layers to bond strongly.

[0145] Module efficiency EQE (External Quantum Efficiency) measurements are performed on all bare cells and modules at 300–1200 nm using the Oriel IQE-200 system. The measured relative ratio is (EQE ベアセル -EQE モジュール ) / EQE ベアセル This ratio is multiplied by the absolute efficiency of the bare cell. This operation is performed at three points on each cell. The average value (%) corresponds to the measured average value of the module efficiency.

[0146] Table 6 shows the properties of the film according to the present invention, composed of EVA with various MP1 loads. The same properties are shown for a film composed of Elvax 150 without phosphors and crosslinking, and for a film composed of another EVA (STR 15420, a photovoltaic encapsulation film material made from EVA with improved curing kinetics and photothermal stability, commercialized by STR, Inc.).

[0147]

[0148] As can be seen, the efficiency of the film according to the present invention at a load of 0.5 wt% MP1 is higher (18.4%) than that of the film made from STR 15420 (17.8%).

[0149] It can also be observed that the total transmission of the film is not significantly affected when the MP1 loading increases from 0.5 to 1 wt%, which can be attributed to the good dispersion of the modified phosphor.

[0150] Table 7 shows the properties of the film according to the present invention, composed of EVA with various MP1 loads. The same properties are shown for a film composed of Elvax 150 without phosphors and crosslinking, and for a film composed of another EVA (STR 15505, a photovoltaic encapsulation film material made from EVA with improved curing reaction kinetics and photothermal stability, commercialized by STR, Inc.).

[0151]

[0152] A similar conclusion can be drawn here from the results in Table 7.

[0153] Based on these results, the film of the present invention having a thickness of 450 nm appears to exhibit haze at 524 nm, preferably less than 35%, and preferably less than 30% (haze is related to the following: % Haze 524nm =Total transmittance (%) 524nm / diffusive transmittance 524nm , (Determined according to the formula, total transmittance and diffuse transmittance were recorded using a UV-VIS spectrometer in 1 nm steps over the range of 450–800 nm.)

[0154] The film of the present invention having a thickness of 450 nm also preferably exhibits a total transmittance of more than 80%, preferably more than 90%, in the 450-800 nm range (total transmittance is recorded with a UV-VIS spectrometer over the 450-800 nm range in 1 nm steps).

Claims

1. A modified phosphor comprising phosphor particles and at least one amphiphilic substance coated thereon, selected from phosphors containing at least one element selected from the group consisting of rare earths, zinc, and manganese, and having an external quantum yield of 40% or more at least over an excitation wavelength comprised between 350 nm and 440 nm; an absorption of 15% or less at wavelengths greater than 440 nm; and an emission spectrum maximum in the wavelength range comprised between 440 nm and 900 nm.

2. A modified phosphor comprising particles of phosphor with at least one amphiphile on their surface.

3. 3. The modified phosphor of claim 1, wherein particles of the modified phosphor are dispersible in a polymer.

4. 4. The modified phosphor of claim 1, wherein the phosphor is selected from the group consisting of aluminates doped with at least one rare earth element and / or manganese, europium-doped phosphates or halophosphates, europium- and / or manganese-doped silicates, cerium-doped rare earth borates or silicates, rare earth oxysulfurs, rare earth vanadates, zinc compounds doped with manganese, zinc, silver and / or copper.

5. The phosphor is ·Formula (Ia) or formula (Ib): A 1 MgAl 10 O 17 :Eu 2+ (Ia) or A 1 MgAl 10 O 17 :Eu 2+ ,Mn 2+ (Ib) (In the formula, A 1 represents at least one of Ba, Sr, or Ca, alone or in combination); Formula (II) or Formula (IIa) or Formula (IIb): a(M 1-d M 1 d O).b(Mg 1-e M 2 e O).c(Al2O3) (II); a(M 1-d Eu d O).b(Mg 1-e Mn e O).c(Al2O3) (IIa);a(Ba 1-d M 1 d O).b(Mg 1-e M 2 e O).c(Al2O3) (IIb) (wherein, M is at least one element selected from Ba, Sr and Ca; M 1 represents a rare earth, preferably at least one of Gd, Tb, Y, Yb, Eu, Nd or Dy, more preferably Eu; M 2 represents at least one of Zn, Mn, and Co, preferably Mn; and a, b, c, d, and e satisfy the following relationships: 0.25≦a≦2.00; 0≦b≦2.00; 3.00≦c≦9.00; 0≦d≦0.4, and 0≦e≦0.

6. (satisfying of; · Formula BaMgAl 10 O 17 ; Ba 0.9 Eu 0.1 MgAl 10 O 17 ; Ba 0.9 Eu 0.1 Mg 0.6 Mn 0.4 Al 10 O 17 ; Ba 0.9 Eu 0.1 Mg 0.8 Mn 0.2 Al 10 O 17 ; Ba 0.9 Eu 0.1 Mg 0.95 Mn 0.05 Al 10 O 17 ; BaMgAl 14 O 23 ; Ba 0.9 Eu 0.1 MgAl 14 O 23 ; Ba 0.8 Eu 0.2 Mg 1.93 Mn 0.07 Al 16 O 27 corresponding to one of 5. The modified phosphor according to claim 1, selected from aluminates.

6. The particles have an average diameter d of at least 0.10 μm and at most 1.00 μm 50 6. The modified phosphor according to claim 1 in the form of particles, having

7. 7. The modified phosphor of claim 1, wherein the at least one amphiphilic substance is selected from the group consisting of linear or branched aliphatic or aromatic acids having 10 to 50 carbon atoms, optionally bearing functional groups, and salts and derivatives thereof.

8. 8. The modified phosphor of claim 1, wherein the amphiphilic substance is selected from the group consisting of linear or branched aliphatic carboxylic acids having 10 to 40 carbon atoms and salts thereof.

9. 9. The modified phosphor of claim 1, wherein the amphiphilic substance is stearic acid or isostearic acid, and isomers thereof, and salts thereof.

10. 10. The modified phosphor of claim 1, wherein the at least one amphiphilic substance is at least 0.1 wt. % and at most 10.0 wt. % relative to the total weight of the phosphor particles.

11. 11. A method for preparing a modified phosphor according to claim 1, comprising the steps of: providing a composition of phosphor particles in a liquid medium; adding at least one amphiphilic substance to the composition; and removing the liquid medium.

12. 11. A composition comprising the modified phosphor according to any one of claims 1 to 10 and at least one polymer.

13. 13. The composition of claim 12, wherein particles of the modified phosphor are dispersed in a polymer.

14. The polymers may be alpha-olefin homo- and copolymers, polycondensation polymers, -na and halogenated polymers -or 14. The composition of claim 12 or 13, wherein the composition is selected from the group consisting of:

15. The polymer contains copolymerized units of ethylene and at least one vinyl carboxylic acid ester. nothing, 14. The composition of claim 12 or 13.

16. 16. The composition of claim 15, wherein the copolymer is crosslinked.

17. 17. The composition according to claim 12, wherein the modified phosphor is present in an amount of at least 0.05% by weight relative to the total weight of the composition.

18. A composition according to any one of claims 12 to 17. With things There was, - the phosphor is an aluminate according to claim 4 or 5; - the at least one amphiphile is stearic acid or isostearic acid, and their isomers and salts; the polymer is a copolymer comprising copolymerized units of ethylene and at least one vinyl carboxylic acid ester as defined in claim 15 or 16, 18. The composition of any one of claims 12 to 17.

19. 19. A film comprising the composition of any one of claims 12 to 18.

20. 35% less Man's 524 nm, the haze being related to the following: 524nm =Total transmittance (%) 524nm / Diffuse transmittance 524nm 20. The film of claim 19 having a thickness of 450 nm, wherein the total transmittance and diffuse transmittance are recorded with a UV-VIS spectrometer over the range of 450 to 800 nm in steps of 1 nm.

21. 80% Super 21. A film according to claim 19 or 20, having a thickness of 450 nm, exhibiting a total transmittance in the range 450-800 nm, said total transmittance being recorded in a UV-VIS spectrometer over the range 450-800 nm in steps of 1 nm.

22. 22. A photovoltaic device comprising a composition according to any one of claims 12 to 18 or a film according to any one of claims 19 to 21.

23. 22. A greenhouse comprising a composition according to any one of claims 12 to 18 or a film according to any one of claims 19 to 21.

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