Optical epoxy molding compound for ambient light sensor and preparation method thereof

Abstract

The present invention belongs to the field of encapsulation materials, and specifically relates to an optical epoxy encapsulant for an ambient light sensor and a preparation method thereof. The preparation raw materials, calculated by mass份数, include: 120 - 180 parts of epoxy resin raw materials, 1 - 30 parts of colorant masterbatch, 1 - 5 parts of hindered amine antioxidants, 120 - 180 parts of anhydride curing agents, and 1 - 5 parts of catalysts; the preparation raw materials of the colorant masterbatch include Cs x WO3, where the range of x is: 0 < x ≤ 2. The present invention selects Cs x WO3 as the colorant, and adopts a compound system of bisphenol A epoxy resin and glycidyl epoxy resin to synergistically regulate through a crosslinked network - colorant dispersion, and stably controls the ultraviolet / infrared transmittance at ≤ 0.6% and the visible light transmittance > 45%, which can effectively shield the interference of ultraviolet and infrared light on the ambient light sensor and improve the accuracy and stability of the sensor.

Description

Technical Field

[0001] The present invention belongs to the field of packaging materials, and in particular relates to an optical epoxy molding compound for an ambient light sensor and a preparation method thereof. Background Art

[0002] Ambient light sensors are increasingly used in modern electronic devices, such as smartphones, tablets, and smartwatches. They automatically adjust screen brightness to suit varying ambient lighting conditions, improving user experience and reducing power consumption. As a key material for encapsulating ambient light sensors, the performance of the optical epoxy molding compound used in these sensors directly impacts their performance.

[0003] Chinese invention patent application CN108192285A provides a high-adhesion epoxy molding compound for optical LED packaging and its preparation method. By selecting a colorless, transparent, and weather-resistant epoxy resin, and while ensuring the product's colorlessness and transparency, a tackifier is used to effectively improve the adhesion between the molding compound and the substrate. However, its application in ambient light sensors may present some problems. First, its shielding effectiveness in the ultraviolet and infrared bands is poor. Ultraviolet light can cause aging and yellowing of the molding compound, reducing its light transmittance and potentially interfering with the sensor's normal detection. Infrared light can cause sensor misjudgment, affecting its accurate perception of ambient light intensity and color. Furthermore, its transmittance in the visible light region is insufficient to meet practical requirements. Some molding compounds, due to internal impurities or structural issues, increase visible light scattering and absorption, weakening the effective light signal received by the sensor, thereby affecting its sensitivity and accuracy.

[0004] Therefore, there is an urgent need to develop an optical epoxy molding compound for ambient light sensors that can effectively shield the ultraviolet and infrared bands and has high transmittance in the visible light region. It has important practical significance and market value. Summary of the Invention

[0005] In order to solve the above technical problems, the first aspect of the present invention provides an optical epoxy molding compound for an ambient light sensor. The raw materials for preparation, calculated by weight, include 120-180 parts of epoxy resin raw material, 1-30 parts of colorant masterbatch, 1-5 parts of hindered amine antioxidant, 120-180 parts of acid anhydride curing agent and 1-5 parts of catalyst;

[0006] The raw materials for preparing the colorant masterbatch include Cs x WO3, where x ranges from: 0 <x≤2。

[0007] In one embodiment, the method for preparing the colorant masterbatch comprises: x WO3 is dispersed in acetone or toluene at room temperature to obtain colorant masterbatch.

[0008] The present invention adopts solvent method to colorant Cs x WO3 is dispersed in acetone or toluene solvent in advance, which can increase the Cs x The dispersibility of WO3 in the subsequent system, on the other hand, the acetone or toluene solvent in the colorant masterbatch will evaporate during the dispersion process, thereby preventing the colorant from being heated and the light transmittance from decreasing during use. The amount of colorant used in the present invention is the amount of colorant masterbatch used.

[0009] In one embodiment, the colorant masterbatch accounts for 0.3-10% of the total mass of the raw materials.

[0010] In one embodiment, the colorant masterbatch accounts for 0.3-1% of the total mass of the raw materials.

[0011] In the present invention, Cs is selected x WO3 is used as a colorant, and the colorant masterbatch is limited to 0.3-10% of the total mass of the raw materials. It can effectively shield the interference of ultraviolet and infrared light on the ambient light sensor, improve the accuracy and stability of the sensor, and ensure high transmittance in the visible light region. The possible reason is that in the range of 0.3-10wt%, Cs x WO3 particles can maintain nano-scale dispersion. When the content exceeds 10wt%, the colorant particles may agglomerate due to van der Waals forces, resulting in a sharp drop in visible light transmittance.

[0012] In one embodiment, the epoxy resin raw material includes bisphenol A epoxy resin and glycidyl ester epoxy resin.

[0013] In one embodiment, the glycidyl ester epoxy resin includes triglycidyl isocyanurate.

[0014] In one embodiment, the type of triglycidyl isocyanurate includes Tepic-s or Tepic-ss, which are from Nissan Chemical Co., Ltd.

[0015] In one embodiment, the bisphenol A epoxy resin includes JER1001 or JER1002, which are from Mitsubishi Chemical Corporation.

[0016] In one embodiment, the mass ratio of the bisphenol A epoxy resin to the glycidyl ester epoxy resin is (3-5):1, which can be 3:1, 4:1, or 5:1.

[0017] The present invention selects a compound of bisphenol A epoxy resin and triglycidyl isocyanurate, and limits their mass ratio to (3-5):1, which can further improve the effective shielding of infrared and ultraviolet rays and the transmittance of visible light. The possible reason is that the trifunctional structure of triglycidyl isocyanurate forms a high-density cross-linked network after curing. At this mass ratio, the rigidity of the cross-linked network can inhibit the aggregation of the colorant and make it uniformly dispersed at the nanometer level, thereby maximizing the ultraviolet and infrared absorption efficiency. In addition, the benzene ring structure in the bisphenol A epoxy resin molecule has inherent absorption in the ultraviolet band of 200-400nm. The matrix itself can assist in absorbing ultraviolet light, and Cs x WO3 forms a synergistic shield; and the aliphatic structure of triglycidyl isocyanurate has high transmittance in the visible light band. After the two are compounded, they can reduce the matrix's absorption of visible light and avoid the decrease in visible light transmittance due to excessive benzene rings of bisphenol A.

[0018] In one embodiment, the acid anhydride curing agent is selected from one or more of tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, and methylhexahydrophthalic anhydride.

[0019] In one embodiment, the acid anhydride curing agent is tetrahydrophthalic anhydride.

[0020] In one embodiment, the hindered amine antioxidant includes hindered amine antioxidant 791.

[0021] In one embodiment, the catalyst is an imidazole catalyst.

[0022] In one embodiment, the imidazole catalyst is 2-ethyl-4-methylimidazole.

[0023] A second aspect of the present invention provides a method for preparing an optical epoxy molding compound for an ambient light sensor, comprising at least the following steps:

[0024] Mixing and stirring the prepared raw materials in parts by weight to obtain an epoxy resin composition;

[0025] crushing the epoxy resin composition and then forming tablets into a cake;

[0026] The adhesive cake is packaged into a device and then cured to obtain an optical epoxy molding compound for an ambient light sensor.

[0027] In one embodiment, the preparation method is specifically as follows: epoxy resin raw materials, colorant masterbatch, anhydride curing agent and hindered amine antioxidant are heated and stirred at 70-90°C for 3-4 hours, a catalyst is added, and the mixture is stirred evenly to obtain an epoxy resin composition; the epoxy resin composition is crushed and then rolled into a gel cake; the gel cake is packaged into a device and then cured to obtain an optical epoxy molding compound for an ambient light sensor.

[0028] Beneficial effects

[0029] (1) The present invention selects Cs x WO3 is used as a colorant, and the colorant masterbatch is limited to 0.3-10% of the total mass of the raw materials. The transmittance of the prepared plastic encapsulation material in the ultraviolet band (200-400nm) and the infrared band (780-1000nm) is less than 1%, which can effectively shield the interference of ultraviolet and infrared light on the ambient light sensor, thereby improving the accuracy and stability of the sensor.

[0030] (2) The transmittance of the plastic encapsulating material prepared by the present invention in the visible light band is greater than 45%. When used in an ambient light sensor, it can ensure that the ambient light sensor can receive sufficient effective light signals, thereby improving the sensitivity and accuracy of the sensor.

[0031] (3) The composite system of bisphenol A epoxy resin and glycidyl ester epoxy resin of the present invention is synergistically regulated by cross-linking network-colorant dispersion to stably control the ultraviolet / infrared transmittance at ≤0.6% and the visible light transmittance at >45%, achieving a balance between ultraviolet / infrared shielding and visible light transmittance.

[0032] (IV) The preparation method of the optical epoxy molding compound for ambient light sensors provided by the present invention has a simple process, controllable cost, and is conducive to industrial application. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a diagram showing the light transmittance test results of the optical epoxy molding compound prepared in Example 1.

[0034] Figure 2 This is a diagram showing the light transmittance test results of the optical epoxy molding compound prepared in Example 2.

[0035] Figure 3 This is a diagram showing the light transmittance test results of the optical epoxy molding compound prepared in Example 3.

[0036] Figure 4 This is a graph showing the light transmittance test results of the optical epoxy molding compound prepared in Comparative Example 1.

[0037] Figure 5 This is a graph showing the light transmittance test results of the optical epoxy molding compound prepared in Comparative Example 2.

[0038] Figure 6 This is a graph showing the light transmittance test results of the optical epoxy molding compound prepared in Comparative Example 3. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the examples and drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. The experimental methods for which specific conditions are not specified in the examples are carried out according to conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used for which the manufacturer is not specified are all conventional products that can be purchased commercially.

[0040] Among them, Cs x WO3 comes from Ningbo Bohuasi Nanotechnology Co., Ltd.

[0041] The model of bisphenol A epoxy resin is JER1001, which comes from Mitsubishi Chemical Corporation.

[0042] The model of triglycidyl isocyanurate is Tepic-s, which comes from Nissan Chemical Co., Ltd.

[0043] Example 1

[0044] In a first aspect of this example, an optical epoxy molding compound for an ambient light sensor is provided. The raw materials for preparation, calculated by weight, include 150 parts of epoxy resin raw material, 2 parts of colorant masterbatch, 3 parts of hindered amine antioxidant, 150 parts of acid anhydride curing agent, and 3 parts of catalyst;

[0045] The raw materials for preparing the colorant masterbatch include Cs x WO3.

[0046] According to the mass fraction, the preparation method of the colorant masterbatch is as follows: 2 parts of Cs x WO3 is dispersed in 100 parts of acetone solvent at 25°C to obtain a colorant masterbatch.

[0047] The epoxy resin raw materials are bisphenol A epoxy resin and triglycidyl isocyanurate, and the mass ratio of the two is 4:1.

[0048] The model of the bisphenol A epoxy resin is JER1001.

[0049] The model of the triglycidyl isocyanurate is Tepic-s.

[0050] The acid anhydride curing agent is tetrahydrophthalic anhydride.

[0051] Hindered amine antioxidants include hindered amine antioxidant 791.

[0052] The catalyst is 2-ethyl-4-methylimidazole.

[0053] The second aspect of this example provides a method for preparing an optical epoxy molding compound for an ambient light sensor, specifically:

[0054] An epoxy resin raw material, a colorant masterbatch, an anhydride curing agent, and a hindered amine antioxidant are heated and stirred at 80°C for 3 hours, and then a catalyst is added and stirred evenly to obtain an epoxy resin composition. The epoxy resin composition is crushed and then formed into a pellet. The pellet is placed in a molding machine, packaged into a device at a temperature of 150°C for 5 minutes, and then continuously cured at 150°C for 4 hours to obtain an optical epoxy molding compound for an ambient light sensor.

[0055] Figure 1 This is a diagram showing the light transmittance test results of the optical epoxy molding compound prepared in Example 1.

[0056] Example 2

[0057] In a first aspect of this example, an optical epoxy molding compound for an ambient light sensor is provided. The raw materials for preparation, calculated by weight, include 150 parts of epoxy resin raw material, 3 parts of colorant masterbatch, 3 parts of hindered amine antioxidant, 150 parts of acid anhydride curing agent, and 3 parts of catalyst;

[0058] The raw materials for preparing the colorant masterbatch include Cs x WO3.

[0059] According to the mass fraction, the preparation method of the colorant masterbatch is as follows: 3 parts of Cs x WO3 is dispersed in 150 parts of acetone solvent at 25°C to obtain a colorant masterbatch.

[0060] The epoxy resin raw materials are bisphenol A epoxy resin and triglycidyl isocyanurate, and the mass ratio of the two is 4:1.

[0061] The model of the bisphenol A epoxy resin is JER1001.

[0062] The model of the triglycidyl isocyanurate is Tepic-s.

[0063] The acid anhydride curing agent is tetrahydrophthalic anhydride.

[0064] Hindered amine antioxidants include hindered amine antioxidant 791.

[0065] The catalyst is 2-ethyl-4-methylimidazole.

[0066] The second aspect of this example provides a method for preparing an optical epoxy molding compound for an ambient light sensor, specifically:

[0067] An epoxy resin raw material, a colorant masterbatch, an anhydride curing agent, and a hindered amine antioxidant are heated and stirred at 80°C for 3 hours, and then a catalyst is added and stirred evenly to obtain an epoxy resin composition. The epoxy resin composition is crushed and then formed into a pellet. The pellet is placed in a molding machine, packaged into a device at a temperature of 150°C for 5 minutes, and then continuously cured at 150°C for 4 hours to obtain an optical epoxy molding compound for an ambient light sensor.

[0068] Figure 2 This is a diagram showing the light transmittance test results of the optical epoxy molding compound prepared in Example 2.

[0069] Example 3

[0070] In a first aspect of this example, an optical epoxy molding compound for an ambient light sensor is provided. The raw materials for preparation, calculated by weight, include 150 parts of epoxy resin raw material, 1 part of colorant masterbatch, 3 parts of hindered amine antioxidant, 150 parts of acid anhydride curing agent, and 3 parts of catalyst;

[0071] The raw materials for preparing the colorant masterbatch include Cs x WO3.

[0072] According to the mass fraction, the preparation method of the colorant masterbatch is as follows: 1 part of Cs x WO3 is dispersed in 50 parts of acetone solvent at 25°C to obtain a colorant masterbatch.

[0073] The epoxy resin raw materials are bisphenol A epoxy resin and triglycidyl isocyanurate, and the mass ratio of the two is 4:1.

[0074] The model of the bisphenol A epoxy resin is JER1001.

[0075] The model of the triglycidyl isocyanurate is Tepic-s.

[0076] The acid anhydride curing agent is tetrahydrophthalic anhydride.

[0077] Hindered amine antioxidants include hindered amine antioxidant 791.

[0078] The catalyst is 2-ethyl-4-methylimidazole.

[0079] The second aspect of this example provides a method for preparing an optical epoxy molding compound for an ambient light sensor, specifically:

[0080] An epoxy resin raw material, a colorant masterbatch, an anhydride curing agent, and a hindered amine antioxidant are heated and stirred at 80°C for 3 hours, and then a catalyst is added and stirred evenly to obtain an epoxy resin composition. The epoxy resin composition is crushed and then formed into a pellet. The pellet is placed in a molding machine, packaged into a device at a temperature of 150°C for 5 minutes, and then continuously cured at 150°C for 4 hours to obtain an optical epoxy molding compound for an ambient light sensor.

[0081] Figure 3 This is a diagram showing the light transmittance test results of the optical epoxy molding compound prepared in Example 3.

[0082] Comparative Example 1

[0083] In a first aspect of this example, an optical epoxy molding compound for an ambient light sensor is provided. The raw materials for preparation, calculated by weight, include 150 parts of epoxy resin raw material, 3 parts of colorant masterbatch, 3 parts of hindered amine antioxidant, 150 parts of acid anhydride curing agent, and 3 parts of catalyst;

[0084] The raw materials for preparing the colorant masterbatch include CuS.

[0085] The preparation method of the colorant masterbatch is as follows: 3 parts of CuS are dispersed in 150 parts of acetone solvent at 25° C. to obtain the colorant masterbatch.

[0086] The epoxy resin raw materials are bisphenol A epoxy resin and triglycidyl isocyanurate, and the mass ratio of the two is 4:1.

[0087] The model of the bisphenol A epoxy resin is JER1001.

[0088] The model of the triglycidyl isocyanurate is Tepic-s.

[0089] The acid anhydride curing agent is tetrahydrophthalic anhydride.

[0090] Hindered amine antioxidants include hindered amine antioxidant 791.

[0091] The catalyst is 2-ethyl-4-methylimidazole.

[0092] The second aspect of this example provides a method for preparing an optical epoxy molding compound for an ambient light sensor, specifically:

[0093] An epoxy resin raw material, a colorant masterbatch, an anhydride curing agent, and a hindered amine antioxidant are heated and stirred at 80°C for 3 hours, and then a catalyst is added and stirred evenly to obtain an epoxy resin composition. The epoxy resin composition is crushed and then formed into a pellet. The pellet is placed in a molding machine, packaged into a device at a temperature of 150°C for 5 minutes, and then continuously cured at 150°C for 4 hours to obtain an optical epoxy molding compound for an ambient light sensor.

[0094] Figure 4 This is a graph showing the light transmittance test results of the optical epoxy molding compound prepared in Comparative Example 1.

[0095] Comparative Example 2

[0096] In a first aspect of this example, an optical epoxy molding compound for an ambient light sensor is provided. The raw materials for preparation, calculated by weight, include 150 parts of epoxy resin raw material, 3 parts of colorant masterbatch, 150 parts of an acid anhydride curing agent, and 3 parts of a catalyst.

[0097] The raw materials for preparing the colorant masterbatch include CuS.

[0098] The preparation method of the colorant masterbatch is as follows: 3 parts of CuS are dispersed in 150 parts of acetone solvent at 25° C. to obtain the colorant masterbatch.

[0099] The epoxy resin raw materials are bisphenol A epoxy resin and triglycidyl isocyanurate, and the mass ratio of the two is 4:1.

[0100] The model of the bisphenol A epoxy resin is JER1001.

[0101] The model of the triglycidyl isocyanurate is Tepic-s.

[0102] The acid anhydride curing agent is tetrahydrophthalic anhydride.

[0103] The catalyst is 2-ethyl-4-methylimidazole.

[0104] The second aspect of this example provides a method for preparing an optical epoxy molding compound for an ambient light sensor, specifically:

[0105] An epoxy resin raw material, a colorant masterbatch, and an acid anhydride curing agent are heated and stirred at 80°C for 3 hours, and then a catalyst is added and stirred evenly to obtain an epoxy resin composition. The epoxy resin composition is crushed and then rolled into a pellet. The pellet is placed in a molding machine, packaged into a device at a temperature of 150°C for 5 minutes, and then continuously cured at 150°C for 4 hours to obtain an optical epoxy molding compound for an ambient light sensor.

[0106] Figure 5This is a graph showing the light transmittance test results of the optical epoxy molding compound prepared in Comparative Example 2.

[0107] Comparative Example 3

[0108] In a first aspect of this example, an optical epoxy molding compound for an ambient light sensor is provided. The raw materials for preparation, calculated by weight, include 150 parts of epoxy resin raw material, 3 parts of colorant masterbatch, 3 parts of hindered amine antioxidant, 150 parts of acid anhydride curing agent, and 3 parts of catalyst;

[0109] The raw materials for preparing the colorant masterbatch include ITO (indium tin oxide).

[0110] The preparation method of the colorant masterbatch is as follows: dispersing 3 parts of ITO in 150 parts of acetone solvent at 25° C. to obtain the colorant masterbatch.

[0111] The epoxy resin raw material is bisphenol A epoxy resin, and the model of the bisphenol A epoxy resin is JER1001.

[0112] The acid anhydride curing agent is tetrahydrophthalic anhydride.

[0113] Hindered amine antioxidants include hindered amine antioxidant 791.

[0114] The catalyst is 2-ethyl-4-methylimidazole.

[0115] The second aspect of this example provides a method for preparing an optical epoxy molding compound for an ambient light sensor, specifically:

[0116] An epoxy resin raw material, a colorant masterbatch, an anhydride curing agent, and a hindered amine antioxidant are heated and stirred at 80°C for 3 hours, and then a catalyst is added and stirred evenly to obtain an epoxy resin composition. The epoxy resin composition is crushed and then formed into a pellet. The pellet is placed in a molding machine, packaged into a device at a temperature of 150°C for 5 minutes, and then continuously cured at 150°C for 4 hours to obtain an optical epoxy molding compound for an ambient light sensor.

[0117] Figure 6 This is a graph showing the light transmittance test results of the optical epoxy molding compound prepared in Comparative Example 3.

[0118] Performance Testing

[0119] 1. Transmittance test: The transmittance of the optical epoxy molding compound prepared in each embodiment and comparative example at 400nm, 480nm and 780nm is tested. The test results are detailed in Figure 1-6 ,The experimental test data are detailed in Table 1.

[0120] Table 1

[0121]

[0122] From Table 1 and Figure 1-6 It can be seen that the optical epoxy molding compounds prepared in Examples 1-3 of the present invention have visible light transmittance greater than 45%, and their UV / IR transmittance is stably controlled at ≤ 0.6%, making them suitable for use in ambient light sensors. However, the optical epoxy molding compounds prepared in Comparative Examples 1-3 fail to achieve a balance between UV / IR shielding and visible light transmittance.

Claims

1. An optical epoxy molding compound for an ambient light sensor, characterized in that: The raw materials for preparation include, by weight, 120-180 parts of epoxy resin raw material, 1-30 parts of colorant masterbatch, 1-5 parts of hindered amine antioxidant, 120-180 parts of acid anhydride curing agent and 1-5 parts of catalyst; The raw materials for preparing the colorant masterbatch include Cs x WO3, where x ranges from: 0 <x≤2; The colorant masterbatch accounts for 0.3-10% of the total mass of the raw materials; The epoxy resin raw materials are bisphenol A epoxy resin and triglycidyl isocyanurate; the mass ratio of the bisphenol A epoxy resin to triglycidyl isocyanurate is (3-5):

1.

2. The optical epoxy molding compound according to claim 1, wherein: The colorant masterbatch accounts for 0.3-1% of the total mass of the raw materials.

3. The optical epoxy molding compound according to claim 1, wherein: The acid anhydride curing agent is selected from one or more of tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, and methylhexahydrophthalic anhydride.

4. The optical epoxy molding compound according to claim 1, wherein: The hindered amine antioxidant includes hindered amine antioxidant 791.

5. The optical epoxy molding compound according to claim 1, wherein: The catalyst is an imidazole catalyst.

6. A method for preparing an optical epoxy molding compound for an ambient light sensor according to any one of claims 1 to 5, characterized in that: At least the following steps are included: Mixing and stirring the prepared raw materials in parts by weight to obtain an epoxy resin composition; crushing the epoxy resin composition and then forming tablets into a cake; The adhesive cake is packaged into a device and then cured to obtain an optical epoxy molding compound for an ambient light sensor.

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