Multilayer composite nano-scattering plate and preparation method thereof

Abstract

The present invention belongs to the field of optical technologies, and particularly relates to a multi-layer composite nano-scattering plate and a preparation method thereof. The scattering plate includes a light-incident layer (1) for receiving light and a light-emitting layer (2) for emitting light; the light-incident layer can form Rayleigh scattering and includes 1 to 5 single-layer structures; the light-emitting layer is a light diffusion layer. In the scattering plate of the present invention, the light-incident layer adopts a single-layer or multi-layer structure, and small-sized nano-particles A are added, which is beneficial to the conduction of light, does not block the transmission of blue light, and at the same time scatters blue light to form a blue sky effect. Nano-particles B are added to the light-emitting layer, or structures such as leather texture and frosting are adopted to play a role in light diffusion, achieving a certain light transmittance and haze; the scattering plate of the present invention is beneficial to improving the light emission efficiency, reducing light loss from the light-incident layer to the light-emitting layer.

Description

Technical Field

[0001] The present invention belongs to the technical field of optics, and particularly relates to a multi-layer composite nano-scattering plate and a preparation method thereof. Background Art

[0002] The sky appears blue because after the sun's rays enter the atmosphere, they are scattered when encountering atmospheric molecules and particles suspended in the atmosphere. The shorter-wavelength purple, blue, and cyan light waves are most easily scattered, while the longer-wavelength red, orange, and yellow light has stronger transmission ability and can pass through atmospheric molecules and particles, maintaining its original direction and being rarely scattered by air molecules. For the lower-layer air molecules, mainly blue light is scattered out, so the sky appears blue.

[0003] The blue color of the sky can only be seen at low altitudes. As the altitude increases, due to the increasingly thin air and the sharp decrease in the number of atmospheric molecules, the light scattered by the molecules gradually weakens, and the brightness of the sky becomes darker and darker. At altitudes above 20 kilometers, the scattering effect is hardly noticeable, and the sky becomes black.

[0004] In modern architecture, due to space limitations, natural light is often lacking or there is insufficient daylighting. To improve this situation, artificial lighting fixtures are installed in most buildings. However, the light emitted by these fixtures is always fixed in terms of brightness and color temperature and cannot change like natural light with the change of seasons or time of day, nor can it change with the change of weather conditions. This kind of light can only meet people's lighting needs while ignoring people's needs for natural light and the environment.

[0005] The prior art uses transparent media such as blue transparent glass or acrylic. When light passes through these transparent media, other lights except blue light are absorbed, and the blue light is transmitted through the transparent media. Although such blue glass can form blue light, the emitted light becomes bluer than white light and cannot simulate the feeling of real natural light.

[0006] In the existing light scattering plates, two or more kinds of nano-particles are mixed in a uniform medium. During the propagation of light, the large-particle-size particles block the light waves, reducing the intensity of Rayleigh scattering. And for the nano-particles that achieve the Rayleigh scattering effect, there are extremely high requirements for the particle size and uniform dispersion. There is a problem that the two materials are difficult to be uniformly dispersed, resulting in unstable effects and poor consistency. Summary of the Invention

[0007] The purpose of the present invention is to provide a multi-layer composite nano-scattering plate to form a special optical material with controllable and adjustable blue light dispersion.

[0008] To achieve the purpose of the present invention, the technical scheme adopted by the present invention is as follows:

[0009] The multi-layer composite nano-scattering plate of the present invention comprises a light-incident layer (1) for receiving light and a light-emitting layer (2) for emitting light;

[0010] The light-incident layer comprises a transparent medium and nano-particles A dispersed in the transparent medium for forming Rayleigh scattering;

[0011] The transparent medium comprises PMMA, PS, PC, MS, PET.

[0012] The light-incident layer is a single-layer structure of 1-5 layers;

[0013] The thickness of the single-layer structure is 0.05-6 mm.

[0014] When the light-incident layer is a single-layer structure of 2 layers or more, the concentration of nano-particles dispersed in each single-layer structure increases progressively.

[0015] The nano-particles A for forming Rayleigh scattering are inorganic nano-particles, metal nano-particles or organic nano-particles, with a particle size / cluster particle size of 10-500 nm.

[0016] The light-emitting layer is a light diffusion layer.

[0017] The light-emitting layer comprises a transparent medium and nano-particles B dispersed in the transparent medium for performing a light diffusion function.

[0018] The nano-particles B for performing the light diffusion function are inorganic nano-particles, metal nano-particles or organic nano-particles, with a particle size / cluster particle size of 500 nm-100 μm.

[0019] Alternatively, the light-emitting layer is a frosted, leather-grained, micro-nano structure or coating layer for performing the light diffusion function; the frosted, leather-grained or micro-nano structure is formed by hot pressing with a roller.

[0020] The inorganic nano-particles are: silicon dioxide, titanium dioxide, calcium carbonate, barium sulfate, calcite, indium phosphide, cadmium sulfide, cadmium selenide, cadmium telluride; the organic nano-particles are silicone, acrylic resin, styrene resin; the metal nano-particles are: Ag, Al, Au, Cu.

[0021] The mass concentration of the nano-particles in the transparent medium is 0.01‰-5%.

[0022] The nano-particles A of the present invention have a smaller particle size and can scatter blue light with a shorter wavelength, belonging to Rayleigh scattering; the nano-particles B have a larger particle size than A and play a role in uniformly diffusing light, meeting the requirements of a certain light transmittance and haze.

[0023] The present invention also provides a preparation method of the multi-layer composite nano-scattering plate. The multi-layer structure can be prepared by a multi-layer co-extrusion, hot pressing, coating or casting molding process. The specific method is as follows:

[0024] (1) Add 60 - 70% nanoparticles to an organic solvent, and disperse them by ultrasonic waves to obtain a nanoparticle mixture; wherein, the organic solvent is xylene.

[0025] (2) Add 1% - 2% white oil to a transparent resin substrate, and mix them evenly using a magnetic heating stirrer. After the resin surface is wetted, add the above nanoparticle mixture so that the mass ratio of the nanoparticles accounts for 0.01‰ - 5% of the mass of the resin substrate. Continue to mix evenly using a stirrer, and heat at a low temperature. The heating temperature is 30 - 50°C to volatilize the solvent, and obtain a uniform mixture of resin and nanoparticles.

[0026] (3) Use 1 - 5 extruders to supply resin or a mixture of resin and nanoparticles respectively according to the number of layers of the board, and converge them in a composite die head to obtain a multi-layer board. Among them, the extrusion processing temperature is 180 - 250°C.

[0027] The frosted, leather grain or micro-nano structure on the surface of the board is formed by hot pressing the board through a roller with a corresponding structure after the extrusion die head.

[0028] Specific method for having a coating layer on the surface of the board

[0029] The base resin is extruded as a pure material by an extruder to form a transparent board. Coat a multi-layer structure on one side of the transparent board. First, evenly coat a layer of coating liquid on the surface of the transparent board (the coating liquid uses acrylic resin varnish as the base material and adds a certain proportion of nanoparticles as the functional material), and form a dry film through thermal curing or UV curing. Then, according to the requirement of the number of structure layers, coat a multi-layer structure according to this process.

[0030] Casting molding process

[0031] Add a certain proportion of nanoparticles to a resin prepolymer or polymer solution, inject it into a mold and cure it to form a nano-scattering board.

[0032] Beneficial effects:

[0033] The light-incident side of the board of the present invention adopts a multi-layer structure, adding small-sized nanoparticles A with concentrations increasing from low to high, which is beneficial to light conduction, does not block the transmission of blue light, and at the same time scatters blue light to form a blue sky effect. Nanoparticles B are added to the light-emitting layer to further scatter blue light to form a blue sky effect. At the same time, particles B play a role in evenly diffusing light to meet certain requirements for light transmittance and haze, or adopt structures such as leather grain and frosting to achieve a light diffusion effect.

[0034] The present invention adopts a multi-layer structure. Two different types / functions of nanoparticles are separately dispersed in a single-layer substrate structure according to a certain concentration gradient. The light-scattering particles A are added layer by layer according to different concentrations, which reduces the difficulty of particle dispersion, has better controllability of blue light, and does not affect the light transmittance. The unique design of the multi-layer gradient-changing concentration is beneficial to improving the light emission efficiency and reducing light loss from the light incident surface to the light exit surface. Description of the Drawings

[0035] Figure 1 It is a schematic structural diagram of the multi-layer composite nano-scattering plate of Embodiment 1 of the present invention;

[0036] Figure 2 It is a schematic structural diagram of the multi-layer composite nano-scattering plate of Embodiment 2 of the present invention;

[0037] Figure 3 It is a schematic structural diagram of the multi-layer composite nano-scattering plate of Embodiment 3 of the present invention;

[0038] Figure 4 It is a schematic structural diagram of the scattering plate of Comparative Example 1. Detailed Description of the Invention

[0039] In order to more clearly illustrate the present invention, the present invention will be described in detail below in conjunction with embodiments.

[0040] Embodiment 1

[0041] Using PMMA as the substrate, the plate thickness is 2 mm, and it has a two-layer structure (see specifically Figure 1 ). The first layer is 1.5 mm. Nano-titanium dioxide particles A are uniformly dispersed in the PMMA substrate, and their particle size range is 30-40 nm. These particles play a role in scattering blue light, scattering the blue light band in the light source to form the effect of a blue sky; the second layer is a structural layer of 0.5 mm with a frosted structure on the surface. This layer plays a role in light homogenization and diffusion, achieving a diffusion effect and simultaneously increasing the haze.

[0042] The specific preparation method is as follows:

[0043] (1) Add 50 g of nano-titanium dioxide to 80 ml of xylene, and disperse it evenly by ultrasonic waves to obtain a titanium dioxide suspension;

[0044] (2) Add 100 ml of white oil to 10 kg of PMMA pellets, heat and stir using a magnetic heating stirrer, set the heating temperature at 70 °C. After the PMMA surface is wetted, add the titanium dioxide suspension, and then heat and stir to mix evenly to obtain a uniform mixture of PMMA and titanium dioxide.

[0045] (3) The sheet is extruded using two extruders. The mixture of PMMA and titanium dioxide is added to one extruder, and an equal mass of PMMA is added to the other extruder. The temperature in each zone of Extruders I - IX is set at 180 - 240 °C. The two extruders converge through a die head to obtain a two - layer nano - scattering sheet. The lower transparent layer is hot - pressed by a frosted roller to obtain a frosted surface.

[0046] Example 2

[0047] Using PMMA as the substrate, the sheet has a thickness of 2 mm and a three - layer structure with thicknesses of 0.8 mm, 0.8 mm, and 0.4 mm respectively (see Figure 2 ). Nano - titanium dioxide particles A with a particle size range of 30 - 40 nm are added to the first and second layers. The content in the second layer is more than that in the first layer, which can better guide the scattering of the blue light band in the light source, resulting in a better blue - sky effect. The third layer is a structural layer with a leather - grain structure on the surface.

[0048] The specific preparation method is as follows: According to the method of Example 1, homogeneous mixtures of PMMA and titanium dioxide with two ratios are prepared respectively. The first one is adding 15 g of titanium dioxide to 5 kg of PMMA, and the second one is adding 35 g of titanium dioxide to 5 kg of PMMA. The sheet is extruded through a three - layer co - extrusion extruder. The first and second extruders are respectively added with the above two - ratio mixtures, and the third extruder is added with 5 kg of PMMA. After converging through the die head, a three - layer nano - scattering sheet is obtained. The lower transparent layer is hot - pressed by a roller with a leather - grain structure to obtain a leather - grain surface.

[0049] Example 3

[0050] Using PMMA as the substrate, the sheet has a thickness of 3 mm and a three - layer structure with thicknesses of 1 mm, 1 mm, and 1 mm respectively (see Figure 3 ). Titanium dioxide with a particle size of 40 - 50 nm is added to the first layer, more titanium dioxide with a particle size of 80 - 100 nm is added to the second layer than in the first layer, and silicone microspheres with a particle size of 30 - 50 μm are added to the third layer.

[0051] The specific preparation method is as follows:

[0052] According to the method of Example 1, homogeneous mixtures of PMMA and nano - particles with three ratios are prepared respectively. The first one is adding 30 g of titanium dioxide to 10 kg of PMMA, the second one is adding 70 g of titanium dioxide to 10 kg of PMMA, and the third one is adding 70 g of silicone microspheres to 10 kg of PMMA. The sheet is extruded through a three - layer co - extrusion extruder. The three extruders are respectively added with the above three - ratio mixtures. After converging through the die head, a three - layer nano - scattering sheet is obtained.

[0053] Example 4

[0054] With PC as the base material, the plate thickness is 3 mm, and the thicknesses of the three-layer structure are 1 mm, 1 mm, and 1 mm respectively. Nano-silica particles A are in the first and second layers, with a particle size range of 40 - 50 nm. Its content in the second layer increases more than that in the first layer, which can better guide the scattering of the blue light band in the light source, and the blue sky effect is better. Organosilica microspheres with a particle size of 30 - 50 μm are added to the third layer, which plays a role in light homogenization and diffusion.

[0055] The preparation method is the same as that of Example 3, except that the base material is changed to PC.

[0056] Example 5

[0057] With PMMA as the base material, the plate thickness is 8 mm, and it has a four-layer structure with a thickness of 2 mm for each layer. Nano-silica particles A are added to the first, second, and third layers, with a particle size range of 300 - 400 nm, and the addition ratio increases layer by layer, which can better guide the scattering of the blue light band in the light source, and the blue sky effect is better. Organosilica microspheres with a particle size of 80 - 100 μm are added to the fourth layer, which plays a role in light homogenization and diffusion.

[0058] The specific preparation method is as follows:

[0059] According to the method of Example 1, uniform mixtures of PMMA and nano-particles with four different ratios are prepared. The first one is adding 20 g of titanium dioxide to 10 kg of PMMA, the second one is adding 30 g of titanium dioxide to 10 kg of PMMA, the third one is adding 50 g of titanium dioxide to 10 kg of PMMA, and the fourth one is adding 200 g of organosilica microspheres to 10 kg of PMMA. The plates are extruded through a four-layer co-extrusion extruder. The four extruders are respectively filled with the above four ratios of mixtures, and after converging through the die head, a four-layer nano-scattering plate is obtained.

[0060] Example 6

[0061] With PS as the base material, the plate thickness is 2 mm, and it has a two-layer structure with thicknesses of 1 mm respectively. Nano-silver with a particle size of 30 - 40 nm is added to the first layer, and acrylic resin microspheres with a particle size of 2 - 3 μm are added to the second layer.

[0062] The specific preparation method is as follows:

[0063] According to the method of Example 1, uniform mixtures of PS and nano-particles with two different ratios are respectively prepared. The first one is adding 15 g of nano-silver to 5 kg of PS, and the second one is adding 35 g of acrylic resin microspheres to 5 kg of PS. The plates are extruded through a two-layer co-extrusion extruder. The two extruders are respectively filled with the above two ratios of mixtures, and after converging through the die head, a two-layer nano-scattering plate is obtained.

[0064] Example 7

[0065] Using PMMA as the substrate, pure material is extruded to form a transparent sheet with a thickness of 6 mm. A three-layer structure is coated on one side of the transparent PMMA sheet. First, a coating solution is evenly coated on the surface of the transparent PMMA. (The coating solution uses acrylic resin varnish as the substrate, adds particles as the functional material, adds titanium dioxide with a particle size of 10 - 20 nm, and the addition ratio is 0.1‰). After thermal curing, the dry film layer thickness is 0.05 mm. Then, another coating solution is coated (the coating solution uses acrylic resin varnish as the substrate, adds particles as the functional material, adds titanium dioxide with a particle size of 10 - 20 nm, and the addition ratio is 0.5‰). After thermal curing, the dry film thickness is 0.05 mm. Finally, the third coating solution is coated (the coating solution uses acrylic resin varnish as the substrate, adds particles as the functional material, adds silicone microspheres with a particle size of 500 - 600 nm, and the addition ratio is 1‰). After thermal curing, the dry film thickness is 0.05 mm.

[0066] Example 8

[0067] Using PET as the substrate, pure material is extruded to form a transparent sheet with a thickness of 3 mm. A two-layer structure is coated on one side of the transparent PET sheet. First, a coating solution is evenly coated on the surface of the transparent PET. (The coating solution uses acrylic resin varnish as the substrate, adds nano-aluminum particles as the functional material with a particle size of 80 - 100 nm, and the addition ratio is 0.2‰). After ultraviolet curing, the dry film layer thickness is 0.1 mm. Then, another coating solution is coated (the coating solution uses acrylic resin varnish as the substrate, adds silicone microspheres as the functional material with a particle size of 600 - 700 nm, and the addition ratio is 0.5%). After ultraviolet curing, the dry film thickness is 0.1 mm.

[0068] Example 9

[0069] Using PMMA as the substrate, the sheet thickness is 1 mm, with a two-layer structure. The first layer has a thickness of 0.7 mm and adds titanium dioxide nanoparticles with a particle size range of 10 - 20 nm. The second layer has a thickness of 0.3 mm and adds acrylic resin microspheres with a particle size range of 1 - 2 μm.

[0070] Specific preparation method:

[0071] 5 g of titanium dioxide nanoparticles were added to 10 ml of xylene and dispersed evenly by ultrasonic waves to obtain a titanium dioxide suspension; 10 ml of white oil was added to 1 kg of PMMA pellets, and the mixture was heated and stirred using a magnetic heating stirrer at a heating temperature of 70 °C. After the PMMA surface was wetted, the titanium dioxide suspension was added, and then heating and stirring were continued. The solvent evaporated, and the mixture was evenly mixed to obtain a uniform mixture of PMMA and titanium dioxide with a titanium dioxide ratio of 0.5%; the above mixture was extruded and granulated to obtain granulated materials. 100 g of the granulated materials were taken and mechanically stirred and blended with 10 kg of PMMA pellets to obtain a blend with a titanium dioxide ratio of 0.05‰. Then, 1.25 kg of the blend was taken and mechanically stirred and blended with 3.75 kg of PMMA pellets to obtain a blend with a titanium dioxide ratio of 0.0125‰. The purpose of multiple blending was to ensure the uniformity of the material mixture; a blend of acrylic resin microspheres and PMMA was prepared by the method of Example 1, and the proportion of microspheres was 3%; the two mixtures finally obtained above were used to extrude sheets using two extruders. The temperature of each zone from I to IX of Extruder I was set at 180 - 240 °C. The two extruders converged through a die head to obtain a two-layer nano-scattering plate.

[0072] Comparative Example 1

[0073] Using PMMA as the substrate with a thickness of 2 mm, three kinds of particles were added. One was titanium dioxide with a particle size of 30 - 40 nm, one was silicon dioxide with a particle size of 40 - 50 nm, and the other was silicone microspheres with a particle size of 3 - 5 μm.

[0074] The specific preparation method was as follows:

[0075] According to the method of Example 3, 15 g of titanium dioxide, 35 g of silicon dioxide, and 35 g of silicone microspheres were added to 80 ml of xylene and dispersed by ultrasonic waves to obtain a mixture of three kinds of nanoparticles; 100 ml of white oil was added to 10 kg of PMMA pellets, and the mixture was heated and stirred using a magnetic heating stirrer at a heating temperature of 70 °C. After the PMMA surface was wetted, the above nanoparticle suspension was added, and then heating and stirring were continued. The mixture was evenly mixed to obtain a uniform mixture of PMMA and nanoparticles. The mixture was extruded into a sheet using one extruder, and the temperature of each zone from I to IX of the extruder was set at 180 - 240 °C to obtain a single-layer nano-scattering plate.

[0076] Comparative Example 2

[0077] Using PMMA as the substrate with a thickness of 2 mm, two kinds of particles were added. One was titanium dioxide with a particle size of 30 - 40 nm, and the other was silicone microspheres with a particle size of 3 - 5 μm.

[0078] The specific preparation method was as follows:

[0079] According to the method of Example 3, 50 g of titanium dioxide and 35 g of silicone microspheres were added to 80 ml of xylene, and ultrasonic dispersion was carried out to obtain a mixture of two kinds of nanoparticles; 100 ml of white oil was added to 10 kg of PMMA pellets, and heating and stirring were carried out using a magnetic heating stirrer. The heating temperature was set at 70 °C. After the PMMA surface was wetted, the above-mentioned nanoparticle suspension was added, and then heating and stirring were carried out to mix evenly to obtain a uniform mixture of PMMA and nanoparticles. A single-layer nano-scattering plate was extruded through an extruder, and the temperature of each section of the extruder was set at 180 - 240 °C.

[0080] Table 1

[0081]

[0082] Among them, the light transmittance and haze value were detected using a haze meter. The specific test method: start the instrument and preheat for 5 min. According to the test standard ASTM D1003, place the plate sample into the instrument for testing;

[0083] The color b value was detected using a spectrophotometric colorimeter. The specific method: start the instrument and preheat for 15 min. According to the test standard ASTM D2244, place the sample plate into the instrument for testing;

[0084] For the determination of chromaticity values x and y, the sample plate was assembled into a lamp, and a BM-7 luminance meter was used for detection. What was tested was the reflected color of the sample plate surface after the lamp was lit. Among them, the larger the absolute value of the color b value, the bluer the color of the sample plate; the (x, y) color coordinates correspond to the color in the CIE 1931 chromaticity diagram. In the present invention, the chromaticity coordinates measured for the scattering plate are located in the Greenish Blue region, and different (x, y) coordinate combinations represent different concentrations of blue.

Claims

1. A multi-layer composite nano-scattering plate, characterized in that, the scattering plate comprises a light-incident layer (1) for receiving light and a light-emitting layer (2) for emitting light; the light-incident layer comprises a transparent medium and nano-particles A dispersed in the transparent medium for forming Rayleigh scattering; the nano-particles A for forming Rayleigh scattering are inorganic nano-particles, metal nano-particles or organic nano-particles, with a particle size of 10 nm - 500 nm; the light-incident layer comprises 1 - 5 single-layer structures; when the light-incident layer comprises 2 or more single-layer structures, the concentration of nano-particles dispersed in each single-layer structure increases; the light-emitting layer is a light diffusion layer; the light-emitting layer comprises a transparent medium and nano-particles B dispersed in the transparent medium for light diffusion; or the light-emitting layer is a frosted, leather grain, micro-nano structure or coating layer for light diffusion; the frosted, leather grain or micro-nano structure is formed by roller hot pressing; the nano-particles B for light diffusion are inorganic nano-particles, metal nano-particles or organic nano-particles, with a particle size of 500 nm - 100 μm; the thickness of the single-layer structure is 0.05 mm - 6 mm.

2. The multi-layer composite nano-scattering plate according to claim 1, characterized in that, the transparent medium comprises any one of PMMA, PS, PC, MS, PET.

3. The multi-layer composite nano-scattering plate according to claim 1, characterized in that, the inorganic nano-particles are any one of: silicon dioxide, titanium dioxide, calcium carbonate, barium sulfate, calcite, indium phosphide, cadmium sulfide, cadmium selenide, cadmium telluride; the organic nano-particles are any one of silicone, acrylic resin, styrene resin; the metal nano-particles are any one of: Ag, Al, Au, Cu.

4. The multi-layer composite nano-scattering plate according to claim 1, characterized in that, the mass concentration of the nano-particles A in the transparent medium is 0.01‰ - 5%.

5. The multi-layer composite nano-scattering plate according to claim 1, characterized in that, the preparation method of the multi-layer composite nano-scattering plate successively comprises multi-layer co-extrusion, hot pressing and curing, coating, and casting molding.

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