A composite material for LED packaging and preparation method thereof

Abstract

The invention discloses a composite material for LED packaging and a preparation method thereof. Aluminum borate whiskers have high elastic modulus and good mechanical strength, but are prone to agglomeration. The agglomerated aluminum borate whiskers cannot be used in LED packaging materials. The invention performs hydrophobic modification on the aluminum borate whiskers to enhance the dispersion performance of the aluminum borate whiskers in resin, and reacts with functional groups in the modified aluminum borate whiskers and epoxy resin to enhance the crosslinking density, thereby enhancing the mechanical properties of the composite material. Meanwhile, the invention loads nano zirconium oxide particles on the surface of the modified aluminum borate whiskers, thereby improving the problem of uneven dispersion of the nano zirconium oxide particles in the epoxy resin and enhancing the ultraviolet aging resistance of the composite material. Furthermore, the nano zirconium oxide particles play a role of mechanical riveting between the modified aluminum borate whiskers and the epoxy resin, thereby further enhancing the mechanical properties of the composite material and enabling the composite material to have a higher refractive index.

Description

Technical Field

[0001] The invention relates to the technical field of packaging materials, and in particular to a composite material for LED packaging and a preparation method thereof. Background Art

[0002] In LED (light emitting diode) packaging, common packaging materials are silicone and epoxy resin, which are often used to protect chips, bonding wires and bottom silver plating from corrosion.

[0003] The organic silicon resin currently used in the market has poor bonding strength and low refractive index. Compared with organic silicon materials, the wide application of epoxy resin is mainly due to its excellent bonding, corrosion resistance and electrical properties. However, the main disadvantages of epoxy resin cured products are brittleness, low impact strength, easy stress cracking, weak weather resistance, etc., which affect the quality of its products. Chinese patent document CN107828057A discloses a preparation method and application of a siloxane-modified epoxy resin for LED encapsulation. The prepared siloxane-modified epoxy resin for LED encapsulation has the characteristics of good bonding with the substrate compared with organic silicon resin; compared with epoxy resin, the siloxane-modified epoxy resin has the characteristics of resistance to cold and hot shock and good heat resistance, but the prepared siloxane-modified epoxy resin has a low refractive index and needs to be further improved. Summary of the invention

[0004] In view of the deficiencies of the prior art, the object of the present invention is to provide a composite material for LED packaging and a preparation method thereof. The prepared composite material has the characteristics of high refractive index, strong light transmittance, resistance to ultraviolet aging and excellent mechanical properties.

[0005] In order to achieve the above object, the present invention adopts the following technical scheme:

[0006] A method for preparing a composite material for LED packaging, comprising the following steps:

[0007] (1) dispersing aluminum borate whiskers in a mixed solvent of anhydrous ethanol and deionized water, then adding triethoxysilane epoxy and dibutyltin dilaurate thereto, stirring for reaction, and after the reaction is completed, washing and drying the reaction product to obtain modified aluminum borate whiskers;

[0008] (2) dispersing the modified aluminum borate whiskers in deionized water, then dropping a zirconium oxide precursor solution, stirring and mixing evenly, aging for 2-4 hours, and then centrifuging, and calcining the obtained solid at high temperature to obtain a modified aluminum borate whisker-loaded nano zirconium oxide material;

[0009] (3) The modified aluminum borate whisker-loaded nano-zirconium oxide material is dispersed in an organic solvent, and then epoxy resin, 4-methylhexahydrophthalic anhydride and tetrabutylammonium bromide are added. After mixing evenly, the organic solvent is removed by vacuum distillation to carry out a curing reaction. After the reaction is completed, a composite material for LED packaging is obtained.

[0010] Preferably, in step (1), the mass ratio of aluminum borate whiskers, mixed solvent, epoxytriethoxysilane and dibutyltin dilaurate is 8-10:150-180:1-2:0.4-0.6.

[0011] Preferably, in step (1), the mass ratio of anhydrous ethanol to deionized water in the mixed solvent is 1-1.5:1.

[0012] Preferably, in step (1), the stirring reaction temperature is 40-50° C., and the stirring reaction time is 2-3 h.

[0013] Preferably, in step (2), the mass ratio of the modified aluminum borate whisker, deionized water and zirconium oxide precursor solution is 10:200-250:80-120.

[0014] Preferably, in step (2), the high temperature calcination temperature is 550-600° C., and the high temperature calcination time is 2-3 h.

[0015] Preferably, in step (3), the mass ratio of the modified aluminum borate whisker-loaded nano zirconium oxide material, epoxy resin, 4-methylhexahydrophthalic anhydride and tetrabutylammonium bromide is 8-12:100:15-20:1-2.

[0016] Preferably, in step (3), the curing conditions are: first curing at 60-80°C for 1-2 hours, and then curing at 100-120°C for 3-4 hours.

[0017] The present invention also provides a composite material for LED packaging prepared by the above preparation method.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] (1) Aluminum borate whiskers have high elastic modulus and good mechanical strength, but are prone to agglomeration. Agglomerated aluminum borate whiskers cannot be used in LED packaging materials. The present invention enhances the dispersion performance of aluminum borate whiskers in resin by hydrophobic modification of aluminum borate whiskers. At the same time, the modified aluminum borate whiskers react with functional groups in epoxy resin to increase the crosslinking density, thereby improving the mechanical properties of the composite material.

[0020] (2) The present invention loads nano-zirconia particles on the surface of modified aluminum borate whiskers, which not only improves the problem of uneven dispersion of nano-zirconia particles in epoxy resin and improves the light transmittance and UV aging resistance of the composite material, but also the nano-zirconia particles play a role of mechanical riveting between the modified aluminum borate whiskers and the epoxy resin, further improving the mechanical properties of the composite material and making the composite material have a higher refractive index. DETAILED DESCRIPTION

[0021] The present invention is further described in detail below through specific preferred embodiments, but the present invention is not limited to the following embodiments.

[0022] It should be noted that, unless otherwise specified, the chemical reagents involved in the present invention were purchased through commercial channels.

[0023] The aluminum borate whiskers used in the present invention have a length of 10-60 μm and a diameter of 0.3-3 μm;

[0024] The model of epoxy triethoxysilane is KH-614, which was purchased from Nanjing Xuanhao New Material Technology Co., Ltd.;

[0025] The epoxy resin model is E44, purchased from Wanqing Chemical Technology Co., Ltd., with a transmittance of 80.16% and a refractive index of 1.538;

[0026] The steps of preparing the zirconium oxide precursor solution are as follows: adding 32.7 g of zirconium acetate to 150 g of deionized water, and heating at 80° C. for 30 minutes; then slowly adding 12 g of acetylacetone, controlling the dripping rate, completing the reaction within 40 minutes, and reflux reaction at 80° C. for 40 minutes; then slowly adding 22.22 g of triethylamine for polycondensation, controlling the dripping rate to complete the reaction within 1.5 hours, and reflux reaction at 80° C. for 3 hours; after cooling to 30° C., adding 1.92 g of citric acid, and removing the solvent by rotary evaporation at 60° C. to obtain a water-soluble zirconium oxide precursor, and preparing the water-soluble zirconium oxide precursor with deionized water into a 30 wt % solution to obtain a zirconium oxide precursor solution.

[0027] Example 1

[0028] A method for preparing a composite material for LED packaging, comprising the following steps:

[0029] (1) 8 g of aluminum borate whiskers were dispersed in a mixed solvent of 80 g of anhydrous ethanol and 80 g of deionized water, and then 1 g of epoxytriethoxysilane and 0.4 g of dibutyltin dilaurate were added thereto, and the mixture was stirred at 40° C. for 3 h. After the reaction was completed, the reaction product was washed and dried to obtain modified aluminum borate whiskers;

[0030] (2) dispersing 10 g of modified aluminum borate whiskers in 200 g of deionized water, then dropping 80 g of zirconium oxide precursor solution, stirring and mixing evenly, aging for 2 h, and then centrifuging, and calcining the obtained solid at 550° C. for 3 h to obtain a modified aluminum borate whisker-loaded nano zirconium oxide material;

[0031] (3) 8 g of modified aluminum borate whisker-loaded nano-zirconium oxide material was dispersed in 200 mL of an organic solvent, xylene, and then 100 g of epoxy resin, 15 g of 4-methylhexahydrophthalic anhydride, and 1 g of tetrabutylammonium bromide were added. After mixing evenly, the organic solvent was removed by distillation under reduced pressure. The mixture was first cured at 60 ° C for 2 h and then cured at 100 ° C for 3 h. After the reaction was completed, a composite material for LED packaging was obtained.

[0032] Example 2

[0033] A method for preparing a composite material for LED packaging, comprising the following steps:

[0034] (1) dispersing 10 g of aluminum borate whiskers in a mixed solvent of 100 g of anhydrous ethanol and 80 g of deionized water, then adding 2 g of epoxytriethoxysilane and 0.6 g of dibutyltin dilaurate thereto, stirring and reacting at 50° C. for 2 h, and after the reaction is completed, washing and drying the reaction product to obtain modified aluminum borate whiskers;

[0035] (2) dispersing 10 g of modified aluminum borate whiskers in 250 g of deionized water, then dropping 120 g of zirconium oxide precursor solution, stirring and mixing evenly, aging for 4 h, and then centrifuging, and calcining the obtained solid at 600 ° C for 2 h to obtain a modified aluminum borate whisker-loaded nano zirconium oxide material;

[0036] (3) 12 g of modified aluminum borate whisker-loaded nano-zirconium oxide material was dispersed in 200 mL of an organic solvent, xylene, and then 100 g of epoxy resin, 20 g of 4-methylhexahydrophthalic anhydride, and 2 g of tetrabutylammonium bromide were added. After mixing evenly, the organic solvent was removed by distillation under reduced pressure. The mixture was first cured at 80 ° C for 1 h and then cured at 120 ° C for 4 h. After the reaction was completed, a composite material for LED packaging was obtained.

[0037] Example 3

[0038] A method for preparing a composite material for LED packaging, comprising the following steps:

[0039] (1) dispersing 9 g of aluminum borate whiskers in a mixed solvent of 80 g of anhydrous ethanol and 80 g of deionized water, then adding 2 g of epoxytriethoxysilane and 0.5 g of dibutyltin dilaurate thereto, stirring and reacting at 50° C. for 3 h, and after the reaction is completed, washing and drying the reaction product to obtain modified aluminum borate whiskers;

[0040] (2) dispersing 10 g of modified aluminum borate whiskers in 240 g of deionized water, then dropping 100 g of zirconium oxide precursor solution, stirring and mixing evenly, aging for 3 h, and then centrifuging, and calcining the obtained solid at 580° C. for 2 h to obtain a modified aluminum borate whisker-loaded nano zirconium oxide material;

[0041] (3) Disperse 10 g of modified aluminum borate whisker-loaded nano-zirconium oxide material in 200 mL of organic solvent xylene, then add 100 g of epoxy resin, 16 g of 4-methylhexahydrophthalic anhydride and 1.5 g of tetrabutylammonium bromide. After mixing evenly, remove the organic solvent by vacuum distillation. First, cure at 80 ° C for 1 h, then cure at 100 ° C for 4 h. After the reaction is completed, a composite material for LED packaging is obtained.

[0042] Comparative Example 1

[0043] A method for preparing a composite material for LED packaging, comprising the following steps:

[0044] (1) dispersing 9 g of aluminum borate whiskers in a mixed solvent of 80 g of anhydrous ethanol and 80 g of deionized water, then adding 2 g of epoxytriethoxysilane and 0.5 g of dibutyltin dilaurate thereto, stirring and reacting at 50° C. for 3 h, and after the reaction is completed, washing and drying the reaction product to obtain modified aluminum borate whiskers;

[0045] (2) 8 g of modified aluminum borate whiskers and 2 g of nano zirconium oxide material were dispersed in 200 mL of organic solvent xylene, and then 100 g of epoxy resin, 16 g of 4-methylhexahydrophthalic anhydride and 1.5 g of tetrabutylammonium bromide were added. After mixing evenly, the organic solvent was removed by vacuum distillation. The mixture was first cured at 80°C for 1 h and then cured at 100°C for 4 h. After the reaction was completed, a composite material for LED packaging was obtained.

[0046] Comparative Example 2

[0047] A method for preparing a composite material for LED packaging, comprising the following steps:

[0048] (1) dispersing 10 g of aluminum borate whiskers in 240 g of deionized water, then dropping 100 g of a zirconium oxide precursor solution, stirring and mixing evenly, aging for 3 h, and then centrifuging, and calcining the obtained solid at 580° C. for 2 h to obtain an aluminum borate whisker-loaded nano zirconium oxide material;

[0049] (2) Disperse 10 g of aluminum borate whisker-loaded nano-zirconium oxide material in 200 mL of an organic solvent, xylene, and then add 100 g of epoxy resin, 16 g of 4-methylhexahydrophthalic anhydride, and 1.5 g of tetrabutylammonium bromide. After mixing evenly, remove the organic solvent by vacuum distillation. First, cure at 80 ° C for 1 h, and then cure at 100 ° C for 4 h. After the reaction is completed, a composite material for LED packaging is obtained.

[0050] The composite materials for LED packaging prepared in Examples 1-3 and Comparative Examples 1-2 were subjected to performance tests, and the specific steps were as follows:

[0051] Light transmittance test: Shimadzu UV-2550 ultraviolet-visible spectrophotometer was used to measure the light transmittance of the composite material at a wavelength of 600 nm in the visible light range at room temperature, with a blank cuvette as a control;

[0052] Refractive index test: Use a WYW-2 Abbe refractometer to test the refractive index of the sample at a wavelength of 589nm at room temperature, and take the average value for the test at three different positions;

[0053] Tensile strength test: The reference standard is ASTM D638-08, and the test is carried out using the RGM-3030 electronic universal testing machine of Shenzhen Ruige Instrument Co., Ltd. The tensile rate is 10mm / min, and the average value is taken after 3 tests;

[0054] UV aging test: Taking the change in transmittance before and after UV irradiation as an indicator, a 500W mercury lamp was used for irradiation, the wavelength range of the radiation was 250-320nm, the distance between the material and the lamp was 35cm, the irradiation time was 72h, and then the transmittance of the composite material in the visible light range with a wavelength of 600nm was measured; the test results are shown in the following table:

[0055]

[0056] Finally, it should be noted that the above embodiments do not limit the present invention in any form. For those skilled in the art, some modifications and improvements can be made to the present invention. Therefore, any modification or improvement made without departing from the spirit of the present invention belongs to the scope of protection claimed in the present invention.

Claims

1. A method for preparing a composite material for LED packaging, characterized in that: The steps include: (1) dispersing aluminum borate whiskers in a mixed solvent of anhydrous ethanol and deionized water, then adding triethoxysilane epoxy and dibutyltin dilaurate thereto, stirring for reaction, and after the reaction is completed, washing and drying the reaction product to obtain modified aluminum borate whiskers; (2) dispersing the modified aluminum borate whiskers in deionized water, then dropping a zirconium oxide precursor solution, stirring and mixing evenly, aging for 2-4 hours, and then centrifuging, and calcining the obtained solid at high temperature to obtain a modified aluminum borate whisker-loaded nano zirconium oxide material; (3) The modified aluminum borate whisker-loaded nano-zirconium oxide material is dispersed in an organic solvent, and then epoxy resin, 4-methylhexahydrophthalic anhydride and tetrabutylammonium bromide are added. After mixing evenly, the organic solvent is removed by vacuum distillation to carry out a curing reaction. After the reaction is completed, a composite material for LED packaging is obtained.

2. The preparation method according to claim 1, characterized in that: In step (1), the mass ratio of aluminum borate whiskers, mixed solvent, epoxytriethoxysilane and dibutyltin dilaurate is 8-10:150-180:1-2:0.4-0.

6.

3. The preparation method according to claim 1, characterized in that: In step (1), the mass ratio of anhydrous ethanol to deionized water in the mixed solvent is 1-1.5:

1.

4. The preparation method according to claim 1, characterized in that: In step (1), the stirring reaction temperature is 40-50° C., and the stirring reaction time is 2-3 h.

5. The preparation method according to claim 1, characterized in that: In step (2), the mass ratio of modified aluminum borate whiskers, deionized water and zirconium oxide precursor solution is 10:200-250:80-120.

6. The preparation method according to claim 1, characterized in that: In step (2), the high temperature calcination temperature is 550-600° C., and the high temperature calcination time is 2-3 hours.

7. The preparation method according to claim 1, characterized in that: In step (3), the mass ratio of the modified aluminum borate whisker-loaded nano zirconium oxide material, epoxy resin, 4-methylhexahydrophthalic anhydride and tetrabutylammonium bromide is 8-12:100:15-20:1-2.

8. The preparation method according to claim 1, characterized in that: In step (3), the curing conditions are: first curing at 60-80°C for 1-2 hours, and then curing at 100-120°C for 3-4 hours.

9. The composite material for LED packaging prepared by the preparation method according to any one of claims 1 to 8.

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