Solvent-resistant light diffusion microsphere with core-shell structure as well as preparation method and application of solvent-resistant light diffusion microsphere

Abstract

The invention discloses a solvent-resistant photodiffusion microsphere with a core-shell structure and a preparation method and application thereof.The photodiffusion microsphere is of the core-shell structure, the shell is composed of an organosilicon compound, the core is composed of a polymer, the particle size of the photodiffusion microsphere is 1-20 microns, and the photodiffusion microsphere is a high-whiteness microsphere, is uniform in sphere shape, smooth in surface and free of defects, and can be used as a solvent-resistant photodiffusion microsphere. The light diffusion plate and the light diffusion film which are prepared by using the microspheres as the light diffusion agent are high in light transmittance and high in haze.

Description

Technical Field

[0001] The invention relates to a microsphere, and more particularly to a solvent-resistant light-diffusing microsphere with a core-shell structure, and a preparation method and application thereof. Background Art

[0002] LED lighting has many advantages such as long life, energy saving and environmental protection, impact resistance, no harm to the human body and no radiation, simple and beautiful, high efficiency, low heat, etc. However, the light emitted by LED lamps is relatively concentrated and strong, which will form a strong contrast with the surrounding environment, resulting in uneven brightness and glare. Adding light diffuser to the resin lampshade can improve the light diffusion ability of the lampshade without affecting the light efficiency and light transmittance as much as possible, making the light of the LED lamp softer.

[0003] In addition, light diffusers can also be made into light diffusion films, which are widely used in backlight modules of flat panel displays such as liquid crystal displays or plasma displays. Light diffusion films diffuse point light sources or line light sources evenly into uniform, high-brightness surface light sources through the refraction and reflection of light. In order to change the uniformity of optical diffusion films, existing technologies often use the addition of micron-sized inorganic particles to improve their performance, such as adding inorganic particles such as silicon oxide, titanium oxide, aluminum oxide or zinc oxide to the formulation system. However, in the preparation process of the coating liquid, these inorganic particles often agglomerate, which in severe cases will clog the filter element on the liquid supply pipeline, causing poor liquid supply and dark spots on the surface of the light diffusion film, affecting the quality of the optical diffusion product.

[0004] In addition, the organic microspheres used as additives for light diffusion films or light diffusion plates prepared by the prior art are pure organic single components such as polymethyl methacrylate (PMMA) and polystyrene (PS), and do not have good solvent resistance.

[0005] Therefore, it is of great significance to provide a light-diffusing microsphere with good haze and uniformity and solvent resistance. Summary of the invention

[0006] The present invention provides a light diffusion microsphere, which has the characteristics of uniform spherical shape, narrow particle size distribution, solid, smooth surface, no damage, no defects, and resistance to solvents and certain temperatures. The prepared light diffusion plate and light diffusion film have high light transmittance and high haze. To achieve the purpose of the present invention, the technical solution adopted by the present invention is as follows:

[0007] A solvent-resistant light-diffusing microsphere with a core-shell structure, wherein the shell is composed of an organic silicon compound and the core is composed of a polymer, and the particle size of the light-diffusing microsphere is 1 to 20 μm.

[0008] In another preferred embodiment, the raw material for forming the shell comprises the following components in parts by weight:

[0009] 5 to 20 parts of organosilicon compound,

[0010] Silane coupling agent 5-20 parts.

[0011] In another preferred embodiment, the organosilicon compound is selected from methyltrimethoxysilane, methyl orthosilicate, ethyl orthosilicate, propyltrimethoxysilane, 3-(methacryloyloxy)propyltrimethoxysilane, 3-(methacryloyloxy)propyltriethoxysilane, or a combination thereof.

[0012] In another preferred embodiment, the silane coupling agent is selected from silane coupling agent KH-570.

[0013] In another preferred embodiment, the raw material for forming the core comprises the following components in parts by weight:

[0014] 50-120 parts of acrylic acid ester monomer,

[0015] 0-50 parts of styrene monomer,

[0016] Initiator 0.1-2 parts,

[0017] Cross-linking agent 0.05~10.

[0018] In another preferred embodiment, the acrylic acid ester monomer is selected from methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, cyclohexyl methacrylate, isobornyl methacrylate, or a combination thereof.

[0019] In another preferred embodiment, the styrene monomer is selected from styrene, methyl styrene, or a combination thereof.

[0020] In another preferred embodiment, the initiator is selected from azobisisobutyronitrile, azobisisoheptanenitrile, benzoyl peroxide, dodecanoyl peroxide, or a combination thereof.

[0021] In another preferred embodiment, the crosslinking agent is a crosslinking agent with trifunctionality or above, selected from triallyl cyanurate, triallyl isocyanurate, trimethallyl isocyanate, trimethylolpropane trimethacrylate or a combination thereof.

[0022] In another preferred embodiment, the raw material for forming the core further comprises the following components in parts by weight:

[0023] 20-30 parts of dispersion stabilizer,

[0024] Inhibitor 0.1-1 part.

[0025] In another preferred embodiment, the dispersion stabilizer is selected from polyvinyl alcohol, methyl cellulose, ethyl cellulose, hydroxypropyl methyl cellulose, hydroxyethyl cellulose, polyvinyl pyrrolidone, or a combination thereof.

[0026] In another preferred embodiment, the inhibitor is selected from sodium nitrite, methylene blue, sodium sulfide, thiourea, sodium sulfate, ammonium thiocyanate, or a combination thereof, more preferably sodium nitrite.

[0027] The present invention also provides a method for preparing the above-mentioned solvent-resistant light-diffusing microspheres having a core-shell structure, characterized in that the preparation method comprises the following steps:

[0028] (1) Preparation of oil phase: 50 to 120 parts by weight of acrylic monomer, 0 to 50 parts by weight of styrene monomer, 0.01 to 2 parts by weight of initiator and 0.05 to 10 parts by weight of crosslinking agent are mixed at 0 to 40° C. to prepare the oil phase;

[0029] (2) Preparation of an aqueous phase: Add 10 to 30 parts by weight of a dispersion stabilizer to 250 to 350 parts by weight of deionized water, add 0.1 to 1 part by weight of a polymerization inhibitor, stir evenly, and then adjust the pH value of the aqueous phase to 2 to 4 with an acid to form an aqueous phase;

[0030] (3) homogenizing the water-oil phase: pouring the oil phase prepared in step (1) into the water phase prepared in step (2), and homogenizing the mixed liquid to form a suspension;

[0031] (4) Preparation of core: The suspension prepared in step (3) is transferred into a reaction vessel and reacted at 40-100° C. for 3-10 h in an inert gas atmosphere;

[0032] (5) Preparation of shell: 5-20 parts of silane coupling agent and 5-20 parts of silicon compound are added to the system prepared in step (4), and the reaction is continued at 40-100° C. for 5-20 hours in an inert gas atmosphere. The milky white liquid obtained after the reaction is filtered, washed with deionized water, and dried to obtain solvent-resistant light-diffusing microspheres.

[0033] In another preferred embodiment, in step (2), the acid used to adjust the pH value of the aqueous phase is selected from hydrochloric acid, sulfuric acid, phosphoric acid, or a combination thereof.

[0034] In another preferred embodiment, in step (3), homogenization is performed using a homogenization device, the homogenization speed is 1000 to 15000 rpm, and the homogenization time is 10 to 40 min.

[0035] In another preferred embodiment, in steps (4) and (5), the inert gas is selected from nitrogen and argon.

[0036] In another preferred embodiment, in step (4), the reaction temperature is 60-80°C.

[0037] In another preferred embodiment, in step (5), the reaction temperature is 60-80°C.

[0038] The present invention also provides the use of the above-mentioned solvent-resistant light-diffusing microspheres with a core-shell structure in preparing a light-diffusing plate or a light-diffusing film for LED lighting.

[0039] The present invention also provides a light diffusion plate or a light diffusion film for LED lighting, wherein the light diffusion plate or the light diffusion film for LED lighting contains the above-mentioned solvent-resistant light diffusion microspheres with a core-shell structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The following drawings are used to illustrate specific embodiments of the present invention and are not used to limit the scope of the present invention defined by the claims.

[0041] Figure 1 The figure shows a solvent-resistant light-diffusing microsphere with a core-shell structure prepared in a specific embodiment of the present invention, wherein the radius of the microsphere is 1.145 μm and the perimeter is 7.198 μm.

[0042] Figure 2 The figure shows a solvent-resistant light-diffusing microsphere with a core-shell structure prepared in another specific embodiment of the present invention, wherein the radius of the microsphere is 1.139 μm and the perimeter is 7.161 μm. DETAILED DESCRIPTION

[0043] In view of the problems existing in the prior art with light diffuser plates or light diffuser films, the inventors of the present application have discovered through in-depth research that in the process of preparing light diffuser plates or light diffuser films, solvent-resistant light diffuser microspheres with a core-shell structure can be used instead of inorganic particles to configure a uniform coating liquid to obtain a product with good light diffusion effect.

[0044] The solvent-resistant light-diffusing microspheres with a core-shell structure of the present invention have a core-shell structure, wherein the shell is composed of an organic silicon compound, the core is composed of a polymer, and the particle size of the light-diffusing microspheres is 1 to 20 μm.

[0045] The role of the organosilicon compound as a shell is to improve solvent resistance and adjust the refractive index at the same time. The raw materials forming the shell include organosilicon compounds and silane coupling agents. The organosilicon compounds that can be used in the present invention include but are not limited to methyltrimethoxysilane, methyl orthosilicate, ethyl orthosilicate, propyltrimethoxysilane, 3-(methacryloyloxy)propyltrimethoxysilane, 3-(methacryloyloxy)propyltriethoxysilane, or a combination thereof. The silane coupling agent that can be used in the present invention includes but is not limited to silane coupling agent KH-570.

[0046] In a specific embodiment of the present invention, the raw materials for forming the core include acrylic monomers, styrene monomers, initiators, crosslinking agents, dispersion stabilizers and polymerization inhibitors. The acrylic monomers function as the main structure of the microspheres, and the acrylic monomers that can be used in the present invention include but are not limited to methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, cyclohexyl methacrylate, isobornyl methacrylate, or a combination thereof.

[0047] The function of the styrene monomer is to adjust the refractive index so that the product has a wider application range. Different from polymethyl methacrylate PMMA and polystyrene PS, the styrene monomer that can be used in the present invention includes but is not limited to styrene and methyl styrene.

[0048] The initiator is mainly used to initiate free radical polymerization and copolymerization of olefinic and diene monomers. The initiators that can be used in the present invention include but are not limited to azobisisobutyronitrile, azobisisoheptanenitrile, benzoyl peroxide, and dodecanoyl peroxide.

[0049] The function of the cross-linking agent is to increase the cross-linking density of the microsphere polymer. The cross-linking agent that can be used in the present invention includes but is not limited to triallyl cyanurate, triallyl isocyanurate, trimethallyl isocyanate, and trimethylolpropane trimethacrylate.

[0050] The solvent-resistant light-diffusing microspheres with a core-shell structure of the present invention are high-whiteness microspheres, and the microspheres have the characteristics of uniform spherical shape, narrow particle size distribution, solidity, smooth surface, no damage, no defects, solvent resistance and certain temperature resistance.

[0051] Compared with the prior art, the solvent-resistant light-diffusing microspheres with a core-shell structure of the present invention have the following beneficial effects: good solvent resistance and different refractive indices, and a wider range of applications.

[0052] The present invention will be further described below in conjunction with specific examples. It should be understood that these examples are intended only to illustrate the present invention and are not intended to limit the scope of the present invention. The experimental methods for the unrecorded specific conditions in the following examples are usually based on normal conditions or the conditions recommended by the manufacturer. Unless otherwise stated, percentages and parts are weight percentages and weight parts. The "parts" mentioned in the following examples refer to "parts by weight".

[0053] Example 1

[0054] (1) Preparation of oil phase: 100 g of methyl methacrylate, 5 g of trimethylolpropane trimethacrylate and 0.5 g of azobisisobutyronitrile were mixed and stirred at 20° C. for 10 min to form a uniform oil phase;

[0055] (2) Preparation of aqueous phase: 12 g of polyvinyl alcohol was dissolved in 300 g of deionized water, 0.25 g of thiourea was added, stirred evenly, and then hydrochloric acid was added to adjust the pH to 2. The resulting solution was the aqueous phase.

[0056] (3) Homogenization of water and oil phases: Pour the oil phase into the water phase, and disperse the mixed liquid in a homogenizer at 12,000 rpm for 10 min to form a suspension;

[0057] (4) Preparation of microspheres: The suspension was transferred into a high-pressure reactor and reacted at 70°C and 0.6 MPa in a nitrogen atmosphere for 10 h;

[0058] (5) Preparation of core-shell structure: 5 g KH-570 and 5 g methyl orthosilicate were added to the reaction system and the reaction was continued for 5 h. The milky white liquid obtained after the reaction was filtered, washed with deionized water and dried to obtain light diffusion microspheres with an average particle size D50 of 2 μm, a distribution index of 0.8, a whiteness of 98, a Tg of 151°C, and a refractive index of 1.47. There was no change after being immersed in DMF and xylene solvents for 7 days.

[0059] Example 2

[0060] (1) Preparation of oil phase: 72 g of methyl methacrylate, 28 g of styrene, 9 g of triallyl cyanurate and 0.6 g of benzoyl peroxide were mixed and stirred at 20° C. for 10 min to form a uniform oil phase;

[0061] (2) Preparation of aqueous phase: 16 g of hydroxyethyl cellulose was dissolved in 300 g of deionized water, 0.2 g of sodium nitrite was added, stirred evenly, and then hydrochloric acid was added to adjust the pH to 2. The resulting solution was the aqueous phase.

[0062] (3) Homogenization of water and oil phases: Pour the oil phase into the water phase, and disperse the mixed liquid in a homogenizer at 10,000 rpm for 10 min to form a suspension;

[0063] (4) Preparation of microspheres by reaction: The above suspension was transferred into a high pressure reactor and reacted at 80°C and 0.6 MPa pressure for 12 h in a nitrogen atmosphere;

[0064] (5) Preparation of core-shell structure: 5 g KH-570 and 5 g ethyl orthosilicate were added to the reaction system and the reaction was continued for 3 h. The milky white liquid obtained after the reaction was filtered and washed with deionized water and then dried to obtain light diffusion microspheres with an average particle size D50 of 3 μm, a distribution index of 0.69, a whiteness of 98, a Tg of 154°C, and a refractive index of 1.53. There was no change after immersion in DMF and xylene solvents for 7 days.

[0065] Example 3

[0066] (1) Preparation of oil phase: 53 g of methyl methacrylate, 22 g of isooctyl methacrylate, 25 g of styrene, 6 g of trimethylallyl isocyanate and 0.6 g of dodecyl peroxide were mixed and stirred at 20° C. for 10 min to form a uniform oil phase;

[0067] (2) Preparation of aqueous phase: 14 g of polyvinyl pyrrolidone was dissolved in 300 g of deionized water, 0.2 g of sodium nitrite was added, stirred evenly, and then hydrochloric acid was added to adjust the pH to 4. The resulting solution was the aqueous phase.

[0068] (3) Homogenization of water and oil phases: Pour the oil phase into the water phase, and disperse the mixed liquid in a homogenizer at 8000 rpm for 10 min to form a suspension;

[0069] (4) Preparation of microspheres by reaction: The above suspension was transferred into a high pressure reactor and reacted at 70°C and 0.6 MPa pressure for 16 h in a nitrogen atmosphere;

[0070] (5) Preparation of core-shell structure: 5 g KH-570 and 5 g ethyl orthosilicate were added to the reaction system and the reaction was continued for 3 h. The milky white liquid obtained after the reaction was filtered and washed with deionized water and then dried to obtain light diffusion microspheres with an average particle size D50 of 7 μm, a distribution index of 0.73, a whiteness of 98, a Tg of 152°C, and a refractive index of 1.54. There was no change after being immersed in DMF and xylene solvents for 7 days.

[0071] Example 4

[0072] (1) Preparation of oil phase: 50 g of methyl methacrylate, 50 g of ethyl methacrylate, 10 g of styrene, 3 g of triallyl isocyanurate, 0.2 g of azobisisobutyronitrile, and 0.1 g of azobisisoheptanenitrile were mixed and stirred at 20° C. for 10 min to form a uniform oil phase;

[0073] (2) Preparation of aqueous phase: 8 g of polyvinyl alcohol and 5 g of hydroxyethyl cellulose were dissolved in 300 g of deionized water, 0.4 g of sodium sulfide was added, stirred evenly, and then hydrochloric acid was added to adjust the pH to 3. The resulting solution was the aqueous phase.

[0074] (3) Homogenization of water and oil phases: Pour the oil phase into the water phase, and disperse the mixed liquid in a homogenizer at 14,000 rpm for 10 min to form a suspension;

[0075] (4) Preparation of microspheres: The suspension was transferred into a high-pressure reactor and reacted at 60°C and 0.6 MPa in a nitrogen atmosphere for 16 h;

[0076] (5) Preparation of core-shell structure: 5 g KH-570 and 5 g ethyl orthosilicate were added to the reaction system and the reaction was continued for 3 h. The milky white liquid obtained after the reaction was filtered and washed with deionized water and then dried to obtain light diffusion microspheres with an average particle size D50 of 2 μm, a distribution index of 0.77, a whiteness of 98, a Tg of 135°C, and a refractive index of 1.58. There was no change after being immersed in DMF and xylene solvents for 7 days.

[0077] Example 5

[0078] The light diffusion microspheres prepared in Example 1 were mixed with styrene in an amount of 0.5%, and a 1 mm light diffusion plate was obtained after calendering, with a haze of 99% and a light transmittance of 95%.

[0079] Example 6

[0080] The light diffusion microspheres prepared in Example 4 were mixed with high-content solvent-based acrylic acid in an addition amount of 30%, and coated on the surface of the PET film with a coating thickness of 20 μm. After curing, a light diffusion film was obtained with a haze of 99% and a transmittance of 90%.

[0081] The above is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. The above embodiment of the present invention can also be modified in various ways. That is, all simple, equivalent changes and modifications made according to the claims and the description of the present invention fall within the scope of protection of the claims of the present invention. The contents not described in detail in the present invention are all conventional technical contents.

Claims

1. A solvent-resistant light-diffusing microsphere having a core-shell structure, characterized in that: The light-diffusing microspheres have a core-shell structure, wherein the shell is composed of an organic silicon compound and the core is composed of a polymer, and the particle size of the light-diffusing microspheres is 1-20 μm.

2. The solvent-resistant light-diffusing microspheres with a core-shell structure according to claim 1, characterized in that: The raw materials used to form the shell include the following components in parts by weight: 5 to 20 parts of organosilicon compound, Silane coupling agent 5-20 parts.

3. The solvent-resistant light-diffusing microspheres with a core-shell structure according to claim 1, characterized in that: The organosilicon compound is selected from methyltrimethoxysilane, methyl orthosilicate, ethyl orthosilicate, propyltrimethoxysilane, 3-(methacryloxy)propyltrimethoxysilane, 3-(methacryloxy)propyltriethoxysilane, or a combination thereof, and / or The silane coupling agent is selected from silane coupling agent KH-570.

4. The solvent-resistant light-diffusing microspheres with a core-shell structure according to claim 1, characterized in that: The raw materials used to form the core include the following components in parts by weight: 50-120 parts of acrylic acid ester monomer, 0-50 parts of styrene monomer, Initiator 0.1-2 parts, Cross-linking agent 0.05-10 parts.

5. The solvent-resistant light-diffusing microspheres with a core-shell structure according to claim 4, characterized in that: The acrylic acid ester monomer is selected from methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, cyclohexyl methacrylate, isobornyl methacrylate, or a combination thereof. The styrene monomer is selected from styrene, methyl styrene, or a combination thereof, and / or The initiator is selected from azobisisobutyronitrile, azobisisoheptanenitrile, benzoyl peroxide, dodecanoyl peroxide, or a combination thereof, and / or The crosslinking agent is selected from triallyl cyanurate, triallyl isocyanurate, trimethallyl isocyanate, trimethylolpropane trimethacrylate or a combination thereof.

6. The photovoltaic glass mildew-proof powder with high mildew resistance and high fluidity according to claim 4, characterized in that: The material used to form the core also includes the following components in parts by weight: 10 to 30 parts of dispersion stabilizer, Inhibitor 0.1-1 part, Preferably, the dispersion stabilizer is selected from polyvinyl alcohol, methyl cellulose, ethyl cellulose, hydroxypropyl methyl cellulose, hydroxyethyl cellulose, polyvinyl pyrrolidone, gelatin, or a combination thereof. Preferably, the inhibitor is selected from sodium nitrite, methylene blue, sodium sulfide, thiourea, sodium sulfate, ammonium thiocyanate, or a combination thereof, more preferably sodium nitrite.

7. The method for preparing the solvent-resistant light-diffusing microspheres having a core-shell structure according to any one of claims 1 to 6, characterized in that: The preparation method comprises the following steps: (1) Preparation of oil phase: 50 to 120 parts by weight of acrylic monomer, 0 to 50 parts by weight of styrene monomer, 0.01 to 2 parts by weight of initiator and 0.05 to 10 parts by weight of crosslinking agent are mixed at 0 to 40° C. to prepare the oil phase; (2) Preparation of an aqueous phase: Add 10 to 30 parts by weight of a dispersion stabilizer to 250 to 350 parts by weight of deionized water, add 0.1 to 1 part by weight of a polymerization inhibitor, stir evenly, and then adjust the pH value of the aqueous phase to 2 to 4 with an acid to form an aqueous phase; (3) homogenizing the water-oil phase: pouring the oil phase prepared in step (1) into the water phase prepared in step (2), and homogenizing the mixed liquid to form a suspension; (4) Preparation of core: The suspension prepared in step (3) is transferred into a reaction vessel and reacted at 40-100° C. for 3-10 h in an inert gas atmosphere; (5) Preparation of shell: 5-20 parts of silane coupling agent and 5-20 parts of organosilicon compound are added to the system prepared in step (4), and the reaction is continued for 5-20 hours in an inert gas atmosphere. The milky white liquid obtained after the reaction is filtered, washed with deionized water, and dried to obtain solvent-resistant light-diffusing microspheres.

8. The preparation method according to claim 7, characterized in that: In step (2), the acid used to adjust the pH value of the aqueous phase is selected from hydrochloric acid, sulfuric acid, phosphoric acid, or a combination thereof. In step (3), homogenization is performed using a homogenization device, the homogenization speed is 1000 to 15000 rpm, the homogenization time is 10 to 40 min, and / or In steps (4) and (5), the inert gas is selected from nitrogen, argon, helium, and / or In step (4), the reaction temperature is 60 to 80°C, and / or In step (5), the reaction temperature is 60-80°C.

9. Use of the solvent-resistant light-diffusing microspheres with a core-shell structure according to any one of claims 1 to 6 in preparing a light-diffusing plate or a light-diffusing film for LED lighting.

10. A light diffusion plate or light diffusion film for LED lighting, characterized in that: The LED lighting light diffusion plate or light diffusion film contains the solvent-resistant light diffusion microspheres with a core-shell structure as claimed in any one of claims 1 to 6.

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