Dark-colored photoluminescent material

Abstract

To provide a photoluminescent material having beautiful dark colors under light, while having good luminescent properties.SOLUTION: A photoluminescent material comprises 19.8-54.8% of a polymer matrix, 45-80 wt.% of a photoluminescent compound, 0.2-5 wt.% of a first dye system, and optionally 0-1 wt.% of porous silica, and a second dye system or additives, where the total content of the second dye system and additives is 0-15 wt.%. The first dye system comprises one or more kinds of dyes selected from synthetic black pigments and three-color pigments formed by green, blue and red pigments. The invention further relates to an article coated with the photoluminescent material or made as a whole of the photoluminescent material.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a dark-colored photoluminescence material with optimized luminescence performance.

Background Art

[0002] In the prior art, there has been disclosed a storage phosphor made of a mixture of a translucent or semi-translucent material and a photoluminescence pigment made of a rare earth element-doped mineral oxide. As an example, a mixture of 50% borosilicate and 50% strontium aluminate doped with europium and dysprosium (Eu 2+ , Dy 3+ :SrAl2O4), and a mixture of 50% acrylic resin and 50% strontium aluminate doped with europium and dysprosium. The luminescence decay of these materials is exponential at the beginning. When placed in the dark after being saturated with light energy, starting from a luminance of several tens Cd / m 2 , the luminance after 10 minutes in the dark becomes less than 1 Cd / m 2 . And the luminescence decay slowly approaches the asymptotic value at several mCd / m 2 . Thanks to this, these materials can sustain visible luminescence in the dark for up to 12 hours. These luminescent materials are necessary for the good passive readability of diving equipment, and therefore, an improvement in luminescence performance is awaited.

[0003] For aesthetic reasons, these photoluminescence materials can be dyed using a pigment system that is a mixture of pigments and additives.

[0004] It has been recognized that the compounds used in the photoluminescence materials containing pigment pigments have the property of suppressing luminescence characteristics. The luminescence of the storage phosphor occurs as a result of the physicochemical interaction between various compounds of the photoluminescence material.

[0005] Therefore, it is difficult to optimize the coloring performance and the luminescence performance together. Tests were conducted using various carbon blacks for black and, generally, for dark colors. It was observed that this carbon black excessively absorbed light in the absorption and emission ranges of the energy storage pigment, which affected the luminescence performance of the material. Therefore, it is necessary to always find the optimum between color and photoluminescence.

Summary of the Invention

Problems to be Solved by the Invention

[0006] The present invention relates to a novel composition that enables obtaining a beautiful black color under light, generally a beautiful dark color under light, while having good luminescence characteristics.

Means for Solving the Problems

[0007] In such a situation, the present invention proposes adding to the formulation a mixture of pigments that are the three primary colors, namely red, green, and blue, or a synthetic black pigment of the type of C.1 Solvent Black 27, Brilliant Black BN, or Perylene Black, or a combination of the three-color pigment and the synthetic black pigment. This composition can include the three primary colors to obtain a dark color, in which case the color is adjusted by adding the synthetic black pigment. Alternatively, the color can be adjusted by adding a small amount of carbon black. In another embodiment, to obtain a black color with good energy storage intensity, the composition includes only the synthetic black pigment and optionally also a small amount of carbon black.

[0008] Optionally, the photoluminescence material further contains porous silica obtained from algae to enhance its luminescence properties. The porous silica is obtained from the skeletons of diatoms. These diatom skeletons are microalgae, which are single-celled organisms with silica skeletons. In fact, according to the latest biological research, diatoms, which are single-celled algae that make up plankton, are composed of silica nanocells that can absorb sunlight very efficiently and perform photosynthesis efficiently even in the dark deep sea. By adding a limited proportion of porous silica of 1% by weight or less to the photoluminescence material, the luminescence properties can be improved.

[0009] Specifically, the present invention relates to a photoluminescence material comprising 19.8 to 54.8% by weight of a polymer matrix, 45 to 80% by weight of a photoluminescence compound, and 0.2 to 5% by weight of a first pigment system, optionally containing 0 to 1% by weight of porous silica, a second pigment system or an additive, the total proportion of the second pigment system and the additive being 0 to 15% by weight, and the first pigment system containing one or more pigments selected from a three-color pigment formed by a green pigment, a blue pigment and a red pigment, and a synthetic black pigment.

[0010] The present invention further relates to an article entirely made of or coated with the photoluminescence material.

Embodiments for Carrying Out the Invention

[0011] The present invention relates to a dark-colored photoluminescence material that can be used to entirely make an article and to coat an article. This article can be, for example, a component of a timepiece. In particular, the article can be an outer component selected from the group consisting of a middle part, a back part, a bezel, lugs, a push button, a bracelet link, a bracelet, a tang buckle, a clasp, a watch face, a flange, a date disk, a hand, and an index of the watch face. Note that these do not cover all of them.

[0012] The photoluminescence material includes a polymer matrix, a photoluminescence compound, and a first dye system, and optionally includes (consists of) porous silica, an additive, and a second dye system.

[0013] The first dye system that constitutes a more specific subject of the present invention includes one or more dyes selected from primary color pigments formed by red, green, and blue, and a synthetic black pigment, preferably Solvent Black 27, perylene black, and / or Brilliant Black BN. The first dye system is contained in an amount of 0.2 to 5% by weight, preferably 0.3 to 4% by weight, more preferably 0.4 to 2% by weight.

[0014] For example, the main red pigment can be of the carmine (lacquer pigment derived from cochineal), azo, quinacridone, or perylene type. The main green pigment may be of the phthalocyanine or naphthol type, and the main blue pigment may be of the anthraquinone, phthalocyanine, or perylene type. Solvent Black 27 has the formula C 17 H 13 N3O4Cr 1 / 2 For example, it is sold under the brand name, Polysynthren® Black H. Brilliant Black BN, also called Black PN, is an azo-based dye and has the formula C 28 H 17 N5Na4O 14 S4. For example, it can be obtained from Sensient Cosmetic Technologies under the brand name, NOIR BRILLLANT BN 80% E151. Those skilled in the art can also use perylene black.

[0015] According to the first alternative embodiment, the first dye system consists of only three-color pigments. In this alternative embodiment, the ratio of the three colors to the total weight of the photoluminescence material is 0.5 to 4% by weight, preferably 0.7 to 2% by weight. Preferably, the three pigments are present in the same ratio. For example, when adding up to 1.5% by weight of the three-color pigments, each pigment is added so as to be 0.5% by weight with respect to the total weight. This same ratio can also be ignored by setting the ratio of each pigment to 20 to 40%. In the second alternative embodiment, the first dye system consists of three-color pigments at 0.2 to 3% by weight, preferably 0.4 to 1.5% by weight, more preferably 0.4 to 1% by weight, with respect to the total weight of the photoluminescence material, and synthetic black pigments at 0.01 to 1% by weight, preferably 0.02 to 0.5% by weight, more preferably 0.02 to 0.2% by weight, with respect to the total weight of the photoluminescence material. In the third alternative embodiment, the first dye system consists of only synthetic black pigments at 0.2 to 2% by weight, preferably 0.3 to 1.5% by weight, more preferably 0.3 to 1% by weight, with respect to the total weight of the photoluminescence material.

[0016] The polymer matrix is contained at 19.8 to 54.8% by weight, preferably 29.7 to 49.7% by weight, more preferably 34.6 to 44.6% by weight. Note that the upper limit of the polymer matrix is calculated with respect to the photoluminescence material that does not contain porous silica, does not contain the second dye system, and does not contain additives. In the presence of one of these compounds, this upper limit value is reduced so that all compounds in the photoluminescence material do not exceed 100%. In the case of the polymer matrix, the polymer matrix can include all polymers that are translucent or semi-translucent in the visible region. For example, the polymer matrix can be a polymer that is one or more types of resins selected from the acrylic family, polyamide family, polyolefin family, epoxy family, polyurethane family, fluoroelastomer family, and silicone.

[0017] The photoluminescence compound is contained in an amount of 45 to 80% by weight, preferably 50 to 70% by weight, more preferably 55 to 65% by weight. The photoluminescence compound can be composed of a pigment or a pigment encapsulated in a translucent shell. The pigment is preferably a derivative of an alkaline earth aluminate doped with rare earths. In particular, the pigment is of the formula Sr x Al y O z :Eu 2+ , Dy 3+ and is strontium aluminate doped with europium and dysprosium. In particular, the pigment can be Sr4Al 14 O 25 :Eu 2+ , Dy 3+ , or SrAl2O4:Eu 2+ , Dy 3+ and optionally both can be included in the photoluminescence compound. Advantageously, the pigment can have different particle sizes so as to optimally distribute the pigment in volume and avoid free space. Also, due to the presence of different particle sizes in volume in this way, it becomes possible to combine small particles that form shallow surface traps causing high light intensity over a short period and large particles that form deeper traps causing light afterglow over a long period. As an example, the pigment can have a first particle size range centered around a diameter D1 of 500 nm to 10 μm, ideally 500 nm to 5 μm, and a second particle size range centered around a diameter D2 of 10 μm to 500 μm, ideally 10 μm to 20 μm. The particle size is measured by laser particle size analysis ISO 13320:2020, which is optionally supplemented by SEM analysis using secondary electron imaging. In addition, it is possible to sieve and combine small portions of more than two numbers of particle sizes. For example, it is possible to have 20% by weight of a first small portion of 500 nm to 5 μm, 60% by weight of a second small portion of 5 μm to 20 μm, and 20% by weight of a third small portion of 20 μm to 50 μm.

[0018] Optionally, the pigment can be encapsulated within a light-transmissive organic or mineral shell. The organic shell can typically be selected from the polymers mentioned for the polymer matrix. The mineral shell can be, for example, a silica (SiO2) shell obtained by the sol-gel method. Other examples of mineral shells include zirconium oxide (ZrO2) and aluminum oxide (Al2O3).

[0019] The photoluminescence material can optionally further contain, in total, 0 to 15% by weight, preferably 0 to 5% by weight, of a second pigment system and additives. Advantageously, the photoluminescence material contains 0.5 to 5% by weight of the pigment system and additives. The second pigment system preferably contains an organic pigment that does not absorb in the emission wavelength range of the photoluminescence pigment. This organic pigment can be a fluorescent pigment or dye whose absorption is more in the UV range and whose emission is in the visible spectrum. For example, it can be an organic fluorescent pigment or dye such as those with the trade names Radiant and Aralon®. It can also be a semi-translucent pigment or dye with a low absorption rate at the emission wavelength of the energy storage pigment. For example, it can be a semi-translucent pigment or dye by Clariant. The second pigment system can also contain carbon black to adjust the dark color. The proportion of carbon black is 0 to 1% by weight, preferably at most 0.5% by weight, more preferably at most 0.3% by weight. The lower limit when carbon black is present is 0.01% by weight. Thus, the proportion of carbon black is 0.01 to 1% by weight, preferably 0.01 to 0.5% by weight, more preferably 0.01 to 0.3% by weight.

[0020] Metallic pigments and pigments with a true pearl luster effect, UV-resistant additives for protecting the polymer matrix, dispersants such as silanes for promoting the dispersion of additives, and other additives such as silica-type nanoscale fillers for adapting the viscosity parameters of the mixture can also be added.

[0021] Optionally, the photoluminescent material can include porous silica obtained from the skeletons of diatoms. Typically, the average diameter of the pores can be on the order of 500 nm. Optionally, the porous silica can be synthetic porous silica. In the case of synthetic silica, the average diameter of the pores is typically from 0.1 μm to 3 μm. The porous silica is included in an amount of 0 to 1% by weight, preferably 0.01 to 1% by weight, more preferably 0.07 to 0.3% by weight, even more preferably 0.09 to 0.2% by weight.

[0022] A method of manufacturing an article made entirely from a photoluminescent material involves mixing one or more types of polymers intended to form a polymer matrix, preferably with a dispersant. This initial mixing is carried out with respect to a photoluminescent pigment, which may optionally be pre-encapsulated. Then, a first dye system is added to this second mixture, along with any second dye system, additives, and porous silica. This mixture can be made from a liquid resin using a speed mixer or a paddle mixer. The resulting mixture can then be shaped by extrusion. Also, to produce a thermoplastic mixture and convert it into reusable granules for injection molding, the mixture can be made using a twin-screw extruder or a high-speed mixer.

[0023] A method of manufacturing an article coated with a photoluminescent material involves depositing a coating on a substrate by techniques such as screen printing, pad printing, spray coating, etc.

[0024] A test for making a sample entirely from the photoluminescent material uses a dye system containing the three primary colors and Solvent Black 27, SrAl2O3:Eu 2+ , Dy 3+It was carried out by adding the photoluminescence pigment to an epoxy resin having a filler content of 60% by weight. The three primary colors were contained at 0.6% by weight, with the same distribution for each color, and the proportion of Solvent Black 27 was 0.05% by weight. Also, using the same base material, a test was conducted using Solvent Black 27 at a proportion of 0.4% by weight with respect to the total weight as a pigment system. Also, using the same base material, a test was conducted using 1.5% by weight of the three primary colors with respect to the total weight, at a proportion of 0.5% by weight for each color, as a pigment system.

[0025] Also, a test was conducted using an additional 0.2% by weight of porous silica.

[0026] The samples were observed under a D65 light booth. In parallel, comparative tests were conducted using various black pigments, including carbon blacks having different particle sizes and different structures, or minerals such as iron(III) oxide (Fe3O4) using the same base material.

[0027] This material was molded by vacuum casting.

[0028] When using mineral oxides, the luminescent material disappears very quickly. When using carbon black, the color becomes very dark, but when used alone, the decrease in luminance is too large. Tests using the three primary colors alone, Solvent Black 27 alone, and combinations of these two resulted in satisfactory colors under light, and the luminescence performance was improved by 15%. In the test using porous silica, the luminescence characteristics increased by 20% after 10 minutes. These luminescence characteristics were measured according to ISO 17514-2003.

Claims

1. A photoluminescence material comprising 19.8 to 54.8% by weight of a polymer matrix, 45 to 80% by weight of a photoluminescence compound, and 0.2 to 5% by weight of a first pigment system, optionally containing 0 to 1% by weight of porous silica, a second pigment system or an additive, wherein the total proportion of the second pigment system and the additive is 0 to 15% by weight, and the first pigment system contains one or more pigments selected from a three-color pigment formed by a green pigment, a blue pigment and a red pigment, and a synthetic black pigment A photoluminescence material characterized by the above.

2. The synthetic black pigment is Solvent Black 27, Brilliant Black BN, Perylene Black, or a combination of these three. The photoluminescence material according to Claim 1, characterized by the above.

3. Containing 29.7 to 49.7% by weight of the polymer matrix, 50 to 70% by weight of the photoluminescence compound, and 0.3 to 4% by weight of the first pigment system The photoluminescence material according to Claim 1, characterized by the above.

4. Containing 29.7 to 49.7% by weight of the polymer matrix, 50 to 70% by weight of the photoluminescence compound, and 0.3 to 4% by weight of the first pigment system The photoluminescence material according to Claim 1, characterized by the above.

5. The first pigment system contains three-color pigments of 0.5 to 4% by weight, preferably 0.7 to 2% by weight. The photoluminescence material according to Claim 1, characterized by the above.

6. The first pigment system consists of three-color pigments of 0.2 to 3% by weight, preferably 0.4 to 1.5% by weight, more preferably 0.4 to 1% by weight, based on the total weight of the photoluminescence material, and synthetic black pigments of 0.01 to 1% by weight, preferably 0.02 to 0.5% by weight, more preferably 0.02 to 0.2% by weight, based on the total weight of the photoluminescence material. The photoluminescence material according to Claim 1, characterized by the above.

7. The proportions of the green pigment, blue pigment and red pigment are each 20 to 40% by weight based on the total weight of the three-color pigments. The photoluminescence material according to Claim 1, characterized by the above.

8. The green pigment, blue pigment and red pigment are contained in the same proportion in the three-color pigments. The photoluminescence material according to Claim 7, characterized by the above.

9. The first pigment system consists of a synthetic black pigment in a proportion of 0.2 to 2% by weight, preferably 0.3 to 1.5% by weight, more preferably 0.3 to 1% by weight. The photoluminescence material according to claim 1, characterized in that.

10. The second pigment system contains carbon black in a proportion of 0.01 to 1% by weight, preferably 0.01 to 0.5% by weight, more preferably 0.01 to 0.3% by weight, based on the total weight of the photoluminescence material. The photoluminescence material according to claim 1, characterized in that.

11. The porous silica is included in a proportion of 0.01 to 1% by weight, preferably 0.07 to 0.3% by weight, more preferably 0.09 to 0.2% by weight. The photoluminescence material according to claim 1, characterized in that.

12. The porous silica is obtained from the skeletons of diatoms. The photoluminescence material according to claim 1, characterized in that.

13. The photoluminescence compound contains a pigment that is a derivative of an alkaline earth aluminate doped with rare earths. The photoluminescence material according to claim 1, characterized in that.

14. The pigment is of the formula Sr x Al y O z :Eu 2+ ,Dy 3+ and is an alkaline earth aluminate doped with europium and dysprosium The photoluminescence material according to claim 13, characterized in that.

15. The pigment is Sr 4 Al 14 O 25 : Eu 2+ , Dy 3+ , and / or SrAl 2 O 4 : Eu 2+ , Dy 3+ is The photoluminescence material according to claim 14, characterized in that.

16. The photoluminescence compound consists of the pigment encapsulated within an organic or mineral translucent shell. The photoluminescence material according to claim 13, characterized in that.

17. The polymer matrix contains one or more types of resins selected from the acrylic family, polyamide family, polyolefin family, epoxy family, polyurethane family, fluoroelastomer family, and silicone. The photoluminescence material according to claim 1, characterized in that.

18. The organic translucent shell contains one or more types of resins selected from the acrylic family, polyamide family, polyolefin family, epoxy family, polyurethane family, fluoroelastomer family, and silicone. The mineral translucent shell contains silica. The photoluminescence material according to claim 16, characterized in that.

19. The photoluminescence compound contains pigments having various particle sizes. The photoluminescence material according to claim 13, characterized in that.

20. The pigment has at least a first particle size range centered on a diameter D1 of 500 nm to 10 μm and a second particle size range centered on a diameter D2 of 10 μm to 500 μm. The photoluminescence material according to claim 19, characterized in that.

21. An article made of or coated with the photoluminescence material according to claim 1. Characterized by that.

22. It is a component of a timepiece. The article according to claim 21, characterized in that.