Light diffusion powder, preparation method thereof and prepared light diffusion agent

Abstract

The invention relates to the field of auxiliary agent processing, in particular to light diffusion powder, a preparation method thereof and a prepared light diffusion agent. Comprising the following raw materials in parts by weight: 9-9.5 parts of polymethyl methacrylate and 0.5-1.0 part of titanium dioxide. The polymethyl methacrylate is prepared from the following raw materials in the particle size range in parts by weight: 2 to 5 parts of polymethyl methacrylate with the particle size of 26 to 50 m, 1 to 3 parts of polymethyl methacrylate with the particle size of 12 to 25 m and 1 to 3 parts of polymethyl methacrylate with the particle size of 1 to 10 microns. Three kinds of polymethyl methacrylate with different particle sizes are compounded to achieve a synergistic effect, so that the light diffusivity is further improved, and a relatively good light transmission effect is kept. When the silicon rubber light diffusion piece is used in a raw material system of the flexible silica gel LED lamp strip, the distance between the silicon rubber light diffusion piece and the lamp beads can be further shortened, light spots are avoided, the flexible silica gel LED lamp strip which is light, thin and good in flexibility is obtained, and the practicability of the flexible silica gel LED lamp strip is improved.

Description

Technical Field

[0001] This application relates to the field of additive processing, and more specifically, it relates to a light-diffusing powder, a method for preparing the same, and the resulting light-diffusing agent. Background Technology

[0002] Currently, flexible silicone LED light strips possess excellent weather resistance, are environmentally friendly and non-toxic, and have good flexibility, allowing them to be bent arbitrarily. They are widely used in advertising sign design and decoration, landscape lighting, vehicle interior ambient lighting, and supermarket lighting, among other applications. For example... Figure 1 As shown, flexible silicone LED light strips typically include silicone rubber light diffusers, silicone rubber light shields, and a flexible PCB board. When powered on, the light emitted by the LEDs on the flexible PCB board is diffused through the silicone rubber light diffusers, converting the point light source of the LEDs into a surface light source. The silicone rubber light shields block and reflect the light, allowing it to be concentrated on the light diffusers for diffused light emission, thus achieving the purpose of gentle eye protection.

[0003] To achieve the above objectives, the following technical solutions are typically adopted in the market: Option 1: Increase the distance between the LED beads and the silicone rubber diffusion surface of the flexible silicone LED strip to avoid exposing the LED beads. This results in a decrease in the luminous efficacy of the flexible silicone LED strip, a larger overall size, and makes it difficult to handle and install in narrow spaces.

[0004] Option 2: In order to obtain a silicone rubber LED light strip with high luminous efficiency, a relatively thin and light-transmitting size, and better flexibility, the distance between the LED beads and the light-transmitting surface of the silicone rubber is reduced. The number of LED beads on the flexible PCB board is increased to reduce the light spot. This measure significantly increases the cost.

[0005] Option 3: Add light-diffusing powder or paste to the raw material system of flexible silicone LED light strips to improve their light diffusion effect and reduce the possibility of light spots appearing on the silicone rubber diffuser plate; however, currently, when improving the light diffusion effect by increasing the amount of light-diffusing powder or paste, it is often accompanied by a decrease in light transmittance and a decrease in the flexibility and physical properties of silicone rubber. Therefore, further improving the light diffusion effect of light-diffusing powder has become an essential research need to be carried out in this field. Summary of the Invention

[0006] To improve the light diffusion effect of light-diffusing powder and achieve better diffusion performance while maintaining a relatively thin overall thickness of the flexible silicone LED light strip, this application provides a light-diffusing powder, its preparation method, and the resulting light-diffusing agent.

[0007] In a first aspect, this application provides a light-diffusing powder, comprising the following raw materials in parts by weight: 9-9.5 parts of polymethyl methacrylate 0.5-1.0 parts of titanium dioxide; The polymethyl methacrylate is composed of raw materials with the following particle size range in parts by weight: 2-5 parts of polymethyl methacrylate with a particle size of 26-50µm 1-3 parts of polymethyl methacrylate with a particle size of 12-25µm 1-3 parts of polymethyl methacrylate with a particle size of 1-10 μm.

[0008] In the above scheme, polymethyl methacrylate (PMMA) is an organosilicon polyester modified resin with a heat resistance temperature of up to 400℃ and high light transmittance and light diffusion effect. This application uses PMMA with different particle size ranges to mix in a certain amount. The obtained PMMA has a better light diffusion effect. Then it is mixed with titanium dioxide. Titanium dioxide has the effect of blocking light and improving haze. When 9-9.5 parts of PMMA and 0.5-1.0 parts of titanium dioxide are mixed, the light blocking effect of titanium dioxide is small. Therefore, in combination with the light diffusion effect of PMMA, the obtained light diffusion powder has a high light diffusion effect. When it is used in flexible silicone LED light strips, it can improve haze and further improve the light diffusion effect of flexible silicone LED light strips. When it is used in thinner flexible silicone LED light strips, it can further shorten the distance between the silicone rubber light diffuser and the LED beads and reduce the possibility of light spots, thereby obtaining a flexible and thin flexible silicone LED light strip with better flexibility and improving its practicality.

[0009] Preferably, the polymethyl methacrylate is spherical PMMA powder and / or irregularly shaped PMMA powder.

[0010] By using one or more of the above-mentioned polymethyl methacrylate shapes, the light diffuses at different angles due to different structures, thereby improving the light diffusion effect. When the resulting light-diffusing powder is used in flexible silicone LED light strips, the light refraction effect is further improved. This can further shorten the distance between the silicone rubber light diffuser and the LED beads, reduce the possibility of light spots, and reduce the total thickness of the flexible silicone LED light strip, giving it the advantages of being soft and thin.

[0011] Preferably, the titanium dioxide is anatase titanium dioxide, and the particle size of anatase titanium dioxide is 50-150 nm.

[0012] Using anatase titanium dioxide with a particle size in the range of 50-150nm makes it easy to mix thoroughly and evenly with polymethyl methacrylate. The resulting light-diffusing powder is used in flexible silicone LED light strips to achieve a better light diffusion effect.

[0013] Preferably, the titanium dioxide is titanium dioxide activated by a compatibilizer.

[0014] By modifying titanium dioxide with a compatibilizer, the resulting modified titanium dioxide is easily compatible with the raw material system of flexible silicone LED light strips, and achieves better light diffusion effect in combination with polymethyl methacrylate.

[0015] Preferably, the compatibilizer is one or more of the following: silane coupling agent, phthalate coupling agent, and aluminate coupling agent.

[0016] A compatibilizer composed of one or more of silane coupling agents, phthalate coupling agents, and aluminate coupling agents is used to modify titanium dioxide. It is easily compatible with the raw material system of the polymer. With the synergistic effect of polymethyl methacrylate, the resulting light-diffusing powder can be used in flexible silicone LED light strips, which can make them have good flexibility, light transmittance and light diffusion effect.

[0017] Preferably, it also includes 0.5-1.5 parts by weight of synergist.

[0018] Preferably, the synergist is one or more of 3-bis(3-methacryloyloxypropyl)tetra(trimethylsiloxy)disiloxane, 3-[tris(1-methylethoxy)silyl]propyl methacrylate, and N-aminoethyl-3-aminopropyltriethoxysilane.

[0019] 3-Bis(3-methacryloyloxypropyl)tetra(trimethylsiloxy)disiloxane, 3-[tris(1-methylethoxy)silyl]propyl methacrylate, and N-aminoethyl-3-aminopropyltriethoxysilane can promote the uniform mixing of light-diffusing powder and silicone rubber. Therefore, using one or more of these synergists, the resulting light-diffusing powder, when used in flexible silicone LED light strips, can give them excellent flexibility, light transmittance, and light diffusion properties.

[0020] Preferably, the synergist is composed of 3-[tris(1-methylethoxy)silyl]propyl methacrylate and N-aminoethyl-3-aminopropyltriethoxysilane in a weight ratio of 1:(1-2).

[0021] Preferably, the synergist is composed of 3-bis(3-methacryloyloxypropyl)tetra(trimethylsiloxy)disiloxane and 3-[tris(1-methylethoxy)silyl]propyl methacrylate in a weight ratio of 1:(1-2).

[0022] Preferably, the synergist is composed of 3-bis(3-methacryloyloxypropyl)tetra(trimethylsiloxy)disiloxane, 3-[tris(1-methylethoxy)silyl]propyl methacrylate, and N-aminoethyl-3-aminopropyltriethoxysilane in a weight ratio of 1:(1-3).

[0023] Preferably, the synergist is composed of 3-bis(3-methacryloyloxypropyl)tetra(trimethylsiloxy)disiloxane, 3-[tris(1-methylethoxy)silyl]propyl methacrylate, and N-aminoethyl-3-aminopropyltriethoxysilane in a weight ratio of 1:(1-2):(1-3).

[0024] When this application uses multiple compounds selected from 3-bis(3-methacryloyloxypropyl)tetra(trimethylsiloxy)disiloxane, 3-[tris(1-methylethoxy)silyl]propyl methacrylate, and N-aminoethyl-3-aminopropyltriethoxysilane, a synergistic effect is achieved. The resulting light-diffusing powder, when used in flexible silicone LED strips, possesses both excellent flexibility and light diffusion properties. Furthermore, it can further shorten the distance between the silicone rubber light diffuser and the LED beads, reducing the likelihood of light spots. This reduces the overall thickness of the resulting flexible silicone LED strip, resulting in a thinner, more flexible, and more practical strip.

[0025] Secondly, this application provides a method for preparing light-diffusing powder, which adopts the following technical solution: Weigh out 2-5 parts of polymethyl methacrylate with a particle size of 26-50µm, 1-3 parts of polymethyl methacrylate with a particle size of 12-25µm, and 1-3 parts of polymethyl methacrylate with a particle size of 1-10µm according to weight, mix them, and then pretreat them at 100-120℃ for 5-30min to obtain a pretreated polymethyl methacrylate mixture. Then add titanium dioxide and mix it evenly with the pretreated polymethyl methacrylate mixture to obtain light diffusing powder.

[0026] By thoroughly mixing three different particle size ranges of polymethyl methacrylate with titanium dioxide, the raw material system of the light-diffusing powder is uniformly mixed. When used on flexible silicone LED light strips, it achieves a better light-diffusing effect.

[0027] Thirdly, a light diffusing agent is composed of the following raw materials by weight percentage: 30-50% light diffusing powder and the balance being a silicone rubber mixture; said silicone rubber mixture includes methyl vinyl silicone rubber raw rubber, silica, and hydroxyl silicone oil.

[0028] In summary, this application has the following beneficial effects: 1. By compounding three types of polymethyl methacrylate (PMMA) with different particle sizes—26-50µm, 12-25µm, and 1-10µm—a synergistic effect is achieved, further improving its light diffusion while maintaining excellent light transmission. When used in the raw material system of flexible silicone LED light strips, the distance between the silicone rubber light diffuser and the LED beads can be further shortened, eliminating light spots and resulting in thinner and more flexible silicone LED light strips.

[0029] 2. By compounding multiple components of 3-bis(3-methacryloyloxypropyl)tetra(trimethylsiloxy)disiloxane, 3-[tris(1-methylethoxy)silyl]propyl methacrylate, and N-aminoethyl-3-aminopropyltriethoxysilane, a synergistic effect is achieved. When the resulting light-diffusing powder is used in flexible silicone LED light strips, it enables the strips to possess excellent flexibility, light transmittance, and light diffusion. Furthermore, it can further shorten the distance between the silicone rubber light diffuser and the LED beads, reducing the overall thickness of the resulting flexible silicone LED light strip and achieving a thinner, more flexible strip, thus improving its practicality. Attached Figure Description

[0030] Figure 1 This is a structural diagram of a flexible silicone LED light strip. Detailed Implementation

[0031] The following is in conjunction with the appendix Figure 1 The present application will be further described in detail with reference to the embodiments.

[0032] The source of some raw materials; Spherical PMMA powder: Arkema DR101 (France), available in various particle sizes; The vinyl content in methyl vinyl silicone rubber is 0.21-0.24%; the number average molecular weight is 680,000-750,000; the hydroxyl silicone oil (α,ω-dihydroxy polydimethylsiloxane) has a viscosity of 30-45 mm² / s and a hydroxyl content of 0.1%-12%; the hydroxyl content is 3-5%; the hydrogen-containing silicone oil is polymethylhydrosiloxane with a hydrogen content of 0.5-1.5%; the silica is fumed silica with a particle size of 1-5 micrometers; the inhibitor is ethynylcyclohexanol. Example

[0033] Example 1 A method for preparing a light-diffusing powder is as follows: Weigh out 4.5 kg of polymethyl methacrylate (PMMA) with an average particle size of approximately 26 µm, 2.25 kg of PMMA with an average particle size of approximately 12 µm, and 2.25 kg of PMMA with a particle size of 1 µm. Mix them and then pretreat them at 115 °C for 15 min to obtain a pretreated PMMA mixture. Then add 1 kg of titanium dioxide (anatase titanium dioxide) with an average particle size of approximately 50 nm and place them in a high-speed mixer. Stir at 200 rpm for 5 min to ensure thorough mixing and uniformity, thus obtaining light-diffusing powder. The PMMA is spherical.

[0034] Example 2 A method for preparing a light-diffusing powder is as follows: Weigh out 4.34 kg of polymethyl methacrylate (PMMA) with an average particle size of approximately 40 µm, 2.48 kg of PMMA with an average particle size of approximately 20 µm, and 2.48 kg of PMMA with a particle size of 5 µm. Mix them and then pretreat them at 115 °C for 15 min to obtain a pretreated PMMA mixture. Then add 0.7 kg of titanium dioxide (anatase titanium dioxide) with an average particle size of approximately 50 nm and place them in a high-speed mixer. Stir at 200 rpm for 5 min to ensure thorough mixing and obtain the light-diffusing powder. The PMMA is spherical.

[0035] Example 3 A method for preparing a light-diffusing powder is as follows: Weigh out 4.32 kg of polymethyl methacrylate (PMMA) with an average particle size of approximately 50 µm, 2.59 kg of PMMA with an average particle size of approximately 25 µm, and 2.59 kg of PMMA with a particle size of 10 µm. Mix them and then pretreat them at 115 °C for 15 min to obtain a pretreated PMMA mixture. Then add 0.5 kg of titanium dioxide (anatase titanium dioxide) with an average particle size of approximately 50 nm and place them in a high-speed mixer. Stir at 200 rpm for 5 min to ensure thorough mixing and uniformity, thus obtaining light-diffusing powder. The PMMA is spherical.

[0036] Example 4 The difference between Example 4 and Example 2 is that the titanium dioxide is compatibilized titanium dioxide, which is prepared by the following method: 1 kg of γ-methacryloxypropyltrimethoxysilane was hydrolyzed in 5 kg of water, and 10 kg of titanium dioxide was added. The mixture was stirred at 30 r / min for 10 min, filtered, and then dried in an oven at 50 °C for 2 h to obtain compatibilizer-activated titanium dioxide.

[0037] Example 5 The difference between Example 5 and Example 4 is that the light-diffusing powder also includes 0.5 kg of synergist. The light-diffusing powder is prepared by the following method: Weigh out 4.34 kg of polymethyl methacrylate (PMMA) with an average particle size of approximately 50 µm, 2.48 kg of PMMA with an average particle size of approximately 150 µm, and 2.48 kg of PMMA with a particle size of 5 µm. Mix them and then pretreat them at 115 °C for 15 min to obtain a pretreated PMMA mixture. Then add 0.7 kg of titanium dioxide (anatase titanium dioxide) with an average particle size of approximately 50 nm and 0.5 kg of synergist (3-[tris(1-methylethoxy)silyl]propyl methacrylate) and all the pretreated PMMA into a high-speed mixer and stir at 200 rpm for 5 min to ensure thorough mixing and uniformity, thus obtaining light-diffusing powder. The PMMA is spherical.

[0038] Example 6 The difference between Example 6 and Example 5 is that the amount of synergist used is 1.0 kg.

[0039] Example 7 The difference between Example 7 and Example 5 is that the amount of synergist used is 1.5 kg.

[0040] Example 8 The difference between Example 8 and Example 6 is that the synergist is obtained by mixing 3-bis(3-methacryloyloxypropyl)tetra(trimethylsiloxy)disiloxane and 3-[tris(1-methylethoxy)silyl]propyl methacrylate in a weight ratio (kg) of 1:1.

[0041] Example 9 The difference between Example 9 and Example 6 is that the synergist is obtained by weighing and mixing 3-bis(3-methacryloyloxypropyl)tetra(trimethylsiloxy)disiloxane, 3-[tris(1-methylethoxy)silyl]propyl methacrylate, and N-aminoethyl-3-aminopropyltriethoxysilane in a weight ratio of 1:2:1.

[0042] Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that titanium dioxide was replaced in equal amounts with polymethyl methacrylate with an average particle size of about 12µm.

[0043] Comparative Example 2 The difference between Comparative Example 2 and Example 1 is that the amount of titanium dioxide used is 3 kg.

[0044] Comparative Example 3 The difference between Comparative Example 3 and Example 1 is that the amount of titanium dioxide used is 0.1 kg.

[0045] Comparative Example 4 The difference between Comparative Example 4 and Example 1 is that polymethyl methacrylate with an average particle size of about 26 µm was replaced in equal amounts with polymethyl methacrylate with a particle size of 1 µm.

[0046] Comparative Example 5 The difference between Comparative Example 5 and Example 1 is that polymethyl methacrylate with an average particle size of about 12 µm and polymethyl methacrylate with a particle size of 1 µm were replaced in equal amounts with polymethyl methacrylate with an average particle size of about 26 µm.

[0047] Comparative Example 6 The difference between Comparative Example 6 and Example 1 is that polymethyl methacrylate with an average particle size of about 26 µm and polymethyl methacrylate with a particle size of 12 µm were replaced in equal amounts with polymethyl methacrylate with an average particle size of 1 µm.

[0048] Application Example 1 A light diffusing agent is prepared by the following method: Weigh 4.8 kg of methyl vinyl silicone rubber raw rubber, 2 kg of silica, and 0.2 kg of hydroxyl silicone oil and mix them evenly in a processing equipment. Add 3 kg of the light-diffusing powder obtained in Example 1 in 3 batches, mix evenly, and grind into a fine paste to obtain a light-diffusing agent.

[0049] Application Example 2-15 The difference between Application Example 2-15 and Application Example 1 is that the source of the light-diffusing powder is different, as shown in Table 1. Table 1. Sources of light-diffusing powders in Application Examples 1-15

[0050] Performance testing Experimental sample preparation: According to weight percentage, 2% light diffusing agent, 64.99% methyl vinyl silicone rubber raw rubber, 5% hydrogen-containing silicone oil, 3% hydroxyl silicone oil, 0.01% inhibitor, and 25% silica obtained from Application Examples 1-15 were mixed evenly in the production equipment; then 2% platinum catalyst (CAS Registry No. 68478-92-2) was added and mixed evenly, then transferred to a mold, and the mold was placed in a flat vulcanizing machine. After hot pressing at 150°C and 15N for 8 minutes, it was cooled to 30°C and demolded to obtain several experimental samples for the following tests.

[0051] Control group: The light diffusing agent in Application Example 1 was replaced with an equal amount of silicon dioxide, and the rest of the preparation process was the same as that of the experimental sample.

[0052] 1. Test experiment on light source spot Material selection: such as Figure 1 As shown, when the experimental sample obtained by applying Example 1-15 is a silicone rubber light diffuser for a flexible silicone LED light strip, the thickness of the silicone rubber light diffuser is 0.8 mm; the transmittance of the silicone rubber light shield is 0.43%, and the thickness is 0.8 mm; the input voltage of the LED is 12 V, the beam angle is 120 °C, the number of LEDs is 60 per meter, the lumen of a single LED is 16 μm, and the power factor is 0.9.

[0053] Experimental procedure: as follows Figure 1 As shown, the LEDs are mounted on a flexible PCB board (0% light transmittance) and placed inside the cavity of a silicone rubber light-shielding component. The silicone rubber light diffuser obtained in Application Examples 1-15 is then placed on top. After powering on, it is observed whether light spots appear on the silicone rubber light diffuser. When no light spots appear, the vertical distance (H) from the top surface of the silicone rubber light diffuser to the LED is shortened by 0.5 mm each time until spots appear on the silicone rubber light diffuser. The distance between the silicone rubber light diffuser and the LED is recorded. The test is performed 3 times and the average value is taken. The measurement is accurate to two decimal places. The distance in Application Examples 1-15 is recorded as A, and the distance in the control group is recorded as A1. The distance shortening rate is [(A1-A) / A1]*100%. The specific data are shown in Table 2.

[0054] 2. Light transmittance and haze According to GB / T 2410-2008, the transmittance and haze were tested using a transmittance meter. The thickness of the experimental sample was 1 mm, and the test was performed 4 times. The average value was taken. The specific data are shown in Table 2. Table 2 Experimental data from Application Examples 1-15

[0055] Combining Application Example 1 and Application Example 10 with Table 2, it can be seen that the spacing reduction rate and haze of Application Example 1 are greater than those of Application Example 10. This indicates that the light diffusion powder obtained in Example 1 has a better light diffusion effect. It also shows that the present application achieves a better diffusion effect by compounding titanium dioxide with polymethyl methacrylate. At the same time, it can further shorten the spacing between the silicone rubber light diffuser and the LED beads, thereby obtaining a flexible silicone LED light strip with better flexibility and thinness, and improving its practicality.

[0056] Combining Application Example 1 and Application Examples 11-12 with Table 2, it can be seen that the spacing reduction rate and haze of Application Example 1 are both smaller than those of Application Example 11, but the light transmittance is significantly higher. In contrast, the spacing reduction rate and haze of Application Example 12 are significantly smaller than those of Application Example 1, but the light transmittance is larger than that of Example 1. This indicates that Application Example 1 uses the light-diffusing powder obtained in Example 1, which has both better light diffusion effect and light transmittance. Therefore, it further demonstrates that the titanium dioxide dosage range of this application is better.

[0057] Combining Application Example 1 and Application Examples 13-15 with Table 2, it can be seen that the spacing reduction rate and haze of Application Example 1 are both greater than those of Application Examples 13-15. This indicates that Application Example 1 uses the light-diffusing powder obtained in Example 1, which has both better light diffusion effect and light transmittance. This further shows that the present application uses a compound of polymethyl methacrylate with an average particle size of about 250µm, polymethyl methacrylate with a particle size of 1µm, and polymethyl methacrylate with an average particle size of 10µm to achieve a better light diffusion effect and further shorten the spacing between the silicone rubber light diffuser and the LED beads, thereby obtaining a flexible silicone LED light strip with better flexibility and thinner profile, improving its practicality.

[0058] Combining Application Examples 2 and 4 with Table 2, it can be seen that the spacing reduction rate and haze of Application Example 4 are both greater than those of Application Example 2, while the light transmittance does not change much. This indicates that Application Example 4 uses the light-diffusing powder obtained in Example 4, which has both better light diffusion effect and light transmittance. This further shows that when titanium dioxide modified by silane coupling agent can be matched with polymethyl methacrylate and fully mixed evenly in the raw material system of silicone rubber light-diffusing parts, the light diffusion effect of the light-diffusing powder can be further improved.

[0059] Combining Application Examples 4 and 5 with Table 2, it can be seen that the spacing reduction rate and haze of Application Example 4 are smaller than those of Application Example 5, and the light transmittance does not change much. This indicates that Application Example 5 uses the light diffusion powder obtained in the corresponding Example 5, which has a better light diffusion effect. This further shows that the addition of synergist can produce a certain degree of haze after being mixed with silicone rubber, thereby improving the light diffusion effect of silicone rubber light diffusion components.

[0060] Combining Application Examples 8 and 6 with Table 2, it can be seen that the spacing reduction rate and haze of Application Example 6 are both smaller than those of Application Example 8. This indicates that Application Example 8 uses the light-diffusing powder obtained in the corresponding Example 8, which also has a better light-diffusing effect. Furthermore, it shows that when multiple of 3-bis(3-methacryloyloxypropyl)tetra(trimethylsiloxy)disiloxane, 3-[tris(1-methylethoxy)silyl]propyl methacrylate, and N-aminoethyl-3-aminopropyltriethoxysilane are compounded and then blended with silicone rubber, the resulting silicone rubber light diffuser has a better light-diffusing effect. This can further shorten the spacing between the silicone rubber light diffuser and the LED beads, thereby obtaining a flexible silicone LED light strip with better flexibility and thinner profile, improving its practicality.

[0061] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A light-diffusing powder, characterized in that, The raw materials consist of the following parts by weight: 9-9.5 parts of polymethyl methacrylate 0.5-1.0 parts of titanium dioxide; The polymethyl methacrylate is composed of raw materials with the following particle size range in parts by weight: 2-5 parts of polymethyl methacrylate with a particle size of 26-50µm 1-3 parts of polymethyl methacrylate with a particle size of 12-25µm 1-3 parts of polymethyl methacrylate with a particle size of 1-10 μm.

2. The light-diffusing powder according to claim 1, characterized in that: The polymethyl methacrylate is spherical PMMA powder and / or irregularly shaped PMMA powder.

3. The light-diffusing powder according to claim 1, characterized in that: The titanium dioxide is anatase titanium dioxide, and the particle size of anatase titanium dioxide is 50-150 nm.

4. The light-diffusing powder according to claim 1, characterized in that: The titanium dioxide is titanium dioxide activated by a compatibilizer.

5. The light-diffusing powder according to claim 4, characterized in that: The compatibilizer is one or a combination of silane coupling agents, phthalate coupling agents, and aluminate coupling agents.

6. A light-diffusing powder according to any one of claims 1-5, characterized in that: It also includes 0.5-1.5 parts by weight of synergist.

7. The light-diffusing powder according to claim 6, characterized in that: The synergist is one or more of the following: 3-bis(3-methacryloyloxypropyl)tetra(trimethylsiloxy)disiloxane, 3-[tris(1-methylethoxy)silyl]propyl methacrylate, and N-aminoethyl-3-aminopropyltriethoxysilane.

8. A method for preparing the light-diffusing powder according to any one of claims 1-5, characterized in that, Includes the following steps: Weigh out 2-5 parts of polymethyl methacrylate with a particle size of 26-50µm, 1-3 parts of polymethyl methacrylate with a particle size of 12-25µm, and 1-3 parts of polymethyl methacrylate with a particle size of 1-10µm according to weight, mix them, and then pretreat them at 100-120℃ for 5-30min to obtain a pretreated polymethyl methacrylate mixture. Then add titanium dioxide and mix it evenly with the pretreated polymethyl methacrylate mixture to obtain light diffusing powder.

9. A light diffusing agent, characterized in that, The light diffusing agent is composed of the following raw materials by weight percentage: 30-50% light diffusing powder, and the balance being a silicone rubber mixture; the silicone rubber mixture includes methyl vinyl silicone rubber raw rubber, silica, and hydroxyl silicone oil; The light-diffusing powder is the light-diffusing powder according to any one of claims 1-7.

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