Composite heat-resistant diffusion plate and preparation process thereof

Abstract

The invention relates to the technical field of diffusion plate preparation, in particular to a composite heat-resistant diffusion plate and a preparation process thereof.The diffusion plate sequentially comprises a core layer, a middle layer and a surface layer from bottom to top, wherein the middle layer is prepared from the following components in parts by mass: 55 to 60 parts of polyethylene glycol terephthalate, 30 to 40 parts of polybutylene terephthalate, 1.5 to 2 parts of titanate coupling agent, 5 to 8 parts of chopped glass fiber, 5 to 7 parts of phosphorus flame retardant and 0.5 to 1 part of maleic anhydride grafted SEBS. The composite heat-resistant diffusion plate provided by the invention shows remarkable advantages in the aspects of heat resistance, mechanical properties, optical properties, environmental protection and the like through innovative material selection, multi-layer structural design and precise process control, and has a remarkable application prospect.

Description

Technical Field

[0001] The present invention relates to the technical field of diffusion plate preparation, and in particular to a composite heat-resistant diffusion plate and a preparation process thereof. Background Art

[0002] As a core component of liquid crystal displays, LED lighting, and imaging systems, diffusers are designed to achieve uniform, soft illumination by scattering incident light. Currently, general-purpose polystyrene (GPPS) is the mainstream base material for optical diffusers, but it suffers from significant drawbacks: insufficient heat resistance (heat deformation temperature typically below 80°C) and poor impact resistance (notched impact strength <2 kJ / m²). GPPS-based diffusers are susceptible to thermal deformation in long-term high-temperature environments, leading to optical degradation or even failure. During transportation or installation, external impact can easily cause brittle fracture, significantly reducing product yield and service life.

[0003] In recent years, polyester materials have been viewed as a potential alternative to polystyrene (GPPS) for diffuser panels due to their excellent overall performance. For example, polybutylene terephthalate (PBT resin) is formed by the polycondensation of terephthalic acid and 1,4-butanediol. Its linear structure containing ester bonds in the backbone imparts a high melting point (225-230°C), low water absorption (<0.1%), and excellent chemical resistance. It also offers no risk of stress cracking and outstanding long-term thermal aging stability. However, existing research has yet to effectively implement PBT in light diffuser panels. Experiments show that the light diffusion effect of the diffuser plate prepared by directly replacing GPPS with PBT is significantly reduced. The main reasons include: first, the refractive index mismatch. The difference between PBT resin (refractive index 1.55) and traditional glass microbeads (refractive index 1.50-1.53) leads to a decrease in light scattering efficiency; second, poor interface compatibility. Conventional light diffusers (such as inorganic particles) are easy to agglomerate in the PBT matrix, and the uneven distribution causes haze fluctuations (deviation > 20%) and a decrease in transmittance (<80%).

[0004] Therefore, making a diffuser plate that can solve the above-mentioned shortcomings of the diffuser plate not only has great environmental significance, but also has high economic value.

[0005] Purpose of the Invention To overcome the shortcomings of the prior art, the present invention provides a composite heat-resistant diffuser plate and a process for preparing the same. The diffuser plate comprises, from bottom to top, a core layer, an intermediate layer, and a surface layer. The intermediate layer comprises the following components, by weight: 55-60 parts polyethylene terephthalate, 30-40 parts polybutylene terephthalate, 1.5-2 parts titanate coupling agent, 5-8 parts chopped glass fiber, 5-7 parts phosphorus-based flame retardant, and 0.5-1 part maleic anhydride-grafted SEBS. Through innovative material selection, multi-layer structural design, and precise process control, the composite heat-resistant diffuser plate provided by the present invention exhibits significant advantages in terms of heat resistance, mechanical properties, optical properties, and environmental friendliness, and has significant application prospects.

[0006] To achieve the above object, the present invention provides the following technical solutions: A composite heat-resistant diffusion plate comprises, from bottom to top, a core layer, an intermediate layer, and a surface layer; The core layer comprises the following components by mass: 40-50 parts of bisphenol A type unsaturated polyester, 10-20 parts of polybutylene succinate, 5-7 parts of glass microspheres, 1.2-1.5 parts of dicumyl peroxide, 3-5 parts of nano cerium oxide, and 0.8-1 part of kaolin; The intermediate layer comprises the following components in parts by mass: 55-60 parts of polyethylene terephthalate, 30-40 parts of polybutylene terephthalate, 1.5-2 parts of titanate coupling agent, 5-8 parts of chopped glass fiber, 5-7 parts of phosphorus flame retardant, and 0.5-1 part of maleic anhydride grafted SEBS; The surface layer comprises the following components by mass: 30-40 parts of polyethylene terephthalate-1,4-cyclohexanedimethanol, 3-5 parts of nano boron nitride, 8-10 parts of silicone-based light diffuser, 1.5-2 parts of antioxidant, and 3.5-4 parts of modified compatibilizer.

[0007] Preferably, the maleic anhydride grafted SEBS is prepared by the following steps: S11. 80-100 parts by mass of SEBS are dissolved in 500-600 parts by mass of a toluene solution having a concentration of 10-20%, and stirred to form a uniform solution; S12. To the solution treated in step S11, 5-8 parts of maleic anhydride and 0.3-1 parts of benzoyl peroxide were added sequentially, stirred, and heated in an oil bath under nitrogen to 110-130 ° C. for 3-6 hours to obtain a reaction solution; S13. The reaction solution was treated with acetone to precipitate a polymer, which was washed with ethanol 3-4 times and dried under vacuum at 60-80° C. to a constant weight to obtain the maleic anhydride-grafted SEBS.

[0008] Preferably, the modified compatibilizer is prepared by the following steps: S21. 60-80 parts by mass of ethylene - vinyl acetate copolymer was dissolved in 400-500 parts by mass concentration of 10-20% toluene solution, and stirred to form a uniform solution; S22. To the solution treated in step S21, 5-8 parts of glycidyl methacrylate and 0.5-1.5 parts of benzoyl peroxide were added sequentially, stirred, and heated in an oil bath under nitrogen to 110-130 ° C. for 4-8 hours to obtain a modified compatibilizer solution; S23. The modified compatibilizer solution is treated with methanol to precipitate a polymer, which is washed with ethanol 3-4 times and dried under vacuum at 60-80° C. to a constant weight to obtain the modified compatibilizer.

[0009] Preferably, the particle size of the glass microbeads is 15-45 μm; the particle size of the kaolin is 1.5-3 μm.

[0010] Preferably, the titanate coupling agent is further limited to a monoalkoxy pyrophosphate coupling agent.

[0011] Preferably, the chopped glass fibers have a fiber length of 2.5-3.5 mm and a diameter of 10-13 μm; and the phosphorus-based flame retardant is further limited to a phosphate flame retardant.

[0012] Preferably, the silicone-based light diffuser is further limited to an organosilicon composite light diffuser; the antioxidant is selected from one or more of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate and octadecylβ-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate.

[0013] A preparation process for a composite heat-resistant diffusion plate, for producing the composite heat-resistant diffusion plate, comprises the following steps: S1. Premixing of raw materials: The raw materials of the core layer, the middle layer, and the surface layer are respectively put into a high-pressure mixer and mixed and stirred for 10-20 minutes to obtain the corresponding core layer premix, the middle layer premix, and the surface layer premix; S2 extrusion granulation: the core layer premix, the intermediate layer premix were extruded through a twin-screw extruder granulation, the surface premix was extruded through a single-screw extruder granulation to obtain core particles, intermediate layer particles, surface particles; S3. Imprinting molding: The core layer particles and the middle layer particles are respectively put into a twin-screw extruder, and the surface layer particles are put into a single-screw extruder for heating and melting. The three layers are co-extruded and imprinted to obtain the composite heat-resistant diffusion plate.

[0014] Preferably, in step S2, the temperature of each zone of the twin-screw extruder used to prepare the core layer particles is: 160-180°C in the first zone, 190-200°C in the second zone, 210-220°C in the third zone, and the die head temperature is 215-220°C; The temperatures of each zone of the twin-screw extruder used to prepare the intermediate layer particles are: 240-250°C in the first zone, 260-270°C in the second zone, 260-265°C in the third zone, and 265-270°C in the die head. The temperatures of each zone of the single-screw extruder used to prepare the surface layer particles are: 200-210°C in the first zone, 220-230°C in the second zone, 230-240°C in the third zone, and 225-230°C in the die head.

[0015] Preferably, in step S3, the temperature of each zone of the twin-screw extruder for melting the core layer particles is: 190-200° C. in the first zone, 210-220° C. in the second zone, and 205-210° C. in the die head; The temperature of each zone of the twin-screw extruder used for melting the intermediate layer particles is: 260-270°C in the first zone, 275-280°C in the second zone, and 265-270°C in the die head; The temperatures of each zone of the single-screw extruder used for melting the surface layer particles are: 220-230°C in the first zone, 235-240°C in the second zone, and 235-240°C in the die head.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. The core layer uses a cross-linked system of bisphenol A unsaturated polyester and polybutylene succinate, and a free radical initiator to construct a three-dimensional network structure, significantly improving the material's thermal stability and resistance to deformation. The synergistic effect of glass microspheres and nano-cerium oxide not only enhances the rigidity of the matrix, but also delays light aging through refractive index matching and UV absorption mechanisms. 2. The middle layer is reinforced with a polyester alloy matrix and chopped glass fibers, combined with the gas-phase-condensed-phase synergistic flame retardant mechanism of the phosphorus-based flame retardant, achieving highly effective flame retardancy while maintaining high light transmittance. Maleic anhydride-grafted SEBS effectively improves the interfacial compatibility between the fiber and the resin through physical entanglement and chemical bonding between polar functional groups and polyester molecular chains, thereby suppressing mechanical failure caused by stress concentration. 3. The surface layer is based on the scattering phase regulation of the silicone composite light diffuser and the hard phase reinforcement of nano-boron nitride, which improves the surface wear resistance while ensuring uniform light diffusion. The antioxidant inhibits thermal oxidative degradation through free radical capture and peroxide decomposition mechanisms, and the modified compatibilizer achieves interlayer chemical bond bridging through the reaction of epoxy groups and polyester end groups, ensuring the interfacial bonding strength of the multilayer structure. 4. This invention uses layered granulation and gradient temperature-controlled co-extrusion technology to ensure that each layer of material fits tightly together during extrusion to form a stable composite structure, ultimately achieving a balanced improvement in heat resistance, impact resistance, and optical properties. At the same time, the entire production process uses environmentally friendly materials and does not contain harmful substances such as halogens, making the product both safe and durable. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a process flow chart for preparing the composite heat-resistant diffusion plate of the present invention; Figure 2 This is a process flow chart for preparing maleic anhydride grafted SEBS according to the present invention; Figure 3 The present invention is a flow chart of the preparation process of the modified compatibilizer. DETAILED DESCRIPTION

[0018] The present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0019] See also Figure 1-3 , the present invention provides a technical solution: Example 1 A preparation process of a composite heat-resistant diffusion plate: S1. Premixing of raw materials: The raw materials of the core layer, the middle layer, and the surface layer were respectively put into a high-pressure mixer and mixed and stirred for 10 minutes to obtain the corresponding core layer premix, the middle layer premix, and the surface layer premix; S2 extrusion granulation: the core layer premix, the intermediate layer premix were extruded through a twin-screw extruder granulation, the surface premix was extruded through a single-screw extruder granulation to obtain core particles, intermediate layer particles, surface particles; S3. Imprinting molding: The core layer particles and the middle layer particles are respectively put into a twin-screw extruder, and the surface layer particles are put into a single-screw extruder for heating and melting. The three layers are co-extruded and imprinted to obtain the composite heat-resistant diffusion plate.

[0020] In the above process, in step S2, the temperature of each zone of the twin-screw extruder used to prepare the core layer particles is: 160°C in the first zone, 190°C in the second zone, 210°C in the third zone, and the die head temperature is 215°C; The temperatures of each zone of the twin-screw extruder used to prepare the intermediate layer pellets were: 240°C in the first zone, 260°C in the second zone, 265°C in the third zone, and 270°C in the die head. The temperatures of each zone of the single-screw extruder used to prepare the surface layer particles were: 210°C in the first zone, 220°C in the second zone, 230°C in the third zone, and 230°C in the die head; In the above process, in step S3, the temperature of each zone of the twin-screw extruder for melting the core layer particles is: 190°C in the first zone, 210°C in the second zone, and 205°C in the die head; The temperatures of each zone of the twin-screw extruder used to melt the intermediate layer pellets were: 260°C in the first zone, 275°C in the second zone, and 265°C in the die head; The temperatures of the zones of the single-screw extruder used to melt the surface particles were: 220°C in the first zone, 235°C in the second zone, and 240°C in the die head; In the above process, the technical effect of the three-layer co-extrusion is achieved by a T-hanger co-extrusion die head, the flow channel is designed according to the core layer: middle layer: surface layer = 45%: 35%: 20%, the die lip gap tolerance is ±0.02mm, and the pulling speed is 5m / min; the working parameters of the embossing molding are: die head pressure 18MPa, pulling roller pressure 0.8MPa, and cooling water temperature 15°C; In the above process, after the composite heat-resistant diffusion plate is prepared, it can be further subjected to 140° C. hot air circulation annealing for 1 hour to eliminate the internal stress in the diffusion plate; In the above process, the core layer raw materials include the following components in parts by mass (wherein one part by mass is defined as 500 g): The brand of the bisphenol A type unsaturated polyester is UPGF-90; The polybutylene succinate was purchased from Mitsubishi Chemical Corporation; The glass microspheres have a particle size of 15-45 μm, model iM30K, and were purchased from PQ Corp. The particle size of the nano-cerium oxide is 0.4-0.8 μm; The particle size of the kaolin is 1.5-3 μm; In the above process, the intermediate layer raw materials include the following components in parts by mass (wherein one part by mass is defined as 500 g): In the above process, the brand of polyethylene terephthalate is Rynite®935; In the above process, the brand of polybutylene terephthalate is SK605; The titanate coupling agent is further defined as a monoalkoxy pyrophosphate type coupling agent, specifically PN-201; The chopped glass fibers have a fiber length of 3 mm, a diameter of 11 μm, and a model number of ECS303-3H; The phosphorus-based flame retardant is further limited to a phosphate flame retardant, specifically resorcinol bisphosphate; The maleic anhydride grafted SEBS is prepared by the following preparation method: S11. 80 parts by mass of SEBS were dissolved in 500 parts by mass of a 10% toluene solution and stirred to form a uniform solution; S12. To the solution treated in step S11, 5 parts of maleic anhydride and 0.3 parts of benzoyl peroxide were added sequentially, stirred, and heated in an oil bath under nitrogen to 110 ° C. for 3 hours to obtain a reaction solution; S13. The reaction solution was treated with excess acetone to precipitate the polymer, which was washed three times with ethanol and dried under vacuum at 60°C to a constant weight to obtain the maleic anhydride-grafted SEBS; In the above process, the model of SEBS is TSRC 6151; In the above process, the surface layer raw materials include the following components in parts by mass (wherein one part by mass is defined as 500 g): The model of the polyethylene terephthalate-1,4-cyclohexanedimethanol ester is PCTG VX401; The silicone-based light diffuser is further defined as an organosilicon composite light diffuser, and the specific model is X-52-7056A; The antioxidant is pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate; The modified compatibilizer is prepared by the following steps: S21. 60 parts by mass of ethylene - vinyl acetate copolymer was dissolved in 400 parts by mass of a 10% concentration of toluene solution and stirred to form a uniform solution; S22. To the solution treated in step S21, 5 parts of glycidyl methacrylate and 0.5 parts of benzoyl peroxide were added sequentially, stirred, and heated in an oil bath under nitrogen to 110 ° C. for 4 hours to obtain a modified compatibilizer solution; S23. The modified compatibilizer solution was treated with excess methanol to precipitate the polymer, washed three times with ethanol, and dried under vacuum at 60°C to constant weight to obtain the modified compatibilizer; In the above process, the ethylene-vinyl acetate copolymer was purchased from Mitsubishi Chemical Corporation.

[0021] Example 2: Example 2 differs from Example 1 in that, in Example 2, the core layer raw material comprises the following components in parts by mass (wherein, one part by mass is defined as 500 g): The intermediate layer raw materials include the following components in parts by mass (wherein one part by mass is defined as 500 g): The surface layer raw materials include the following components in parts by mass (wherein one part by mass is defined as 500 g): The remaining steps are exactly the same as in Example 2 and Example 1.

[0022] Example 3: Example 3 differs from Example 1 in that, in Example 3, the core layer raw material comprises the following components in parts by mass (wherein, one part by mass is defined as 500 g): The intermediate layer raw materials include the following components in parts by mass (wherein one part by mass is defined as 500 g): The surface layer raw materials include the following components in parts by mass (wherein one part by mass is defined as 500 g): The remaining steps are exactly the same as in Example 3 and Example 1.

[0023] Example 4: Example 4 differs from Example 1 in that, in Example 4, the core layer raw material comprises the following components in parts by mass (wherein, one part by mass is defined as 500 g): The intermediate layer raw materials include the following components in parts by mass (wherein one part by mass is defined as 500 g): The surface layer raw materials include the following components in parts by mass (wherein one part by mass is defined as 500 g): The remaining steps are exactly the same as in Example 4 and Example 1.

[0024] Comparative Example Comparative Example 1: Comparative Example 1 differs from Example 1 in the following manner: the only difference is that, in Comparative Example 1, the preparation of the core layer is omitted, and the remaining steps are exactly the same in Comparative Example 1 and Example 1.

[0025] Comparative Example 2: Comparative Example 2 differs from Example 1 in the following manner: the only difference is that, in Comparative Example 2, the preparation of the surface layer is omitted, and the remaining steps are exactly the same in Comparative Example 2 and Example 1.

[0026] Comparative Example 3: Comparative Example 3 differs from Example 1 in the following manner: the only difference is that, in Comparative Example 3, the preparation of the core layer and the surface layer is omitted, and the remaining steps are exactly the same in Comparative Example 3 and Example 1.

[0027] Performance testing: According to the requirements of GB / T 2410-2008 and GB / T 2410-2008 standards, the transmittance and haze of the prepared composite heat-resistant diffusion board were tested; according to the requirements of GB / T 1843-2008 and GB / T 9341-2008 standards, the notched impact strength and flexural strength of the prepared composite heat-resistant diffusion board were tested; according to the requirements of GB / T 1634.2-2019 and GB / T 2423.3-2016 standards, the heat deformation temperature and long-term heat resistance of the prepared composite heat-resistant diffusion board were tested; according to the requirements of GB / T 2408-2021 standard, the flame retardant properties of the prepared composite heat-resistant diffusion board were tested. The test results are shown below: Referring to the performance test data of Examples 1-4, it can be seen that the transmittance is higher than 87%, the haze is higher than 91%, the notched impact strength is higher than 45kJ / m², the flexural strength is higher than 118MPa, the HDT is higher than 158°C, the heat-resistant light retention rate is higher than 90%, and the UL94 vertical burning grade reaches V-0, with excellent and stable performance. This proves that the composite heat-resistant diffusion plate provided by the present invention has significant advantages in heat resistance, mechanical properties, optical properties and environmental protection through innovative material selection, multi-layer structure design and precise process control, and has obvious application prospects.

[0028] The transmittance and haze of Examples 1-4 are significantly better than those of Comparative Examples 1-3. The reason is that the layered design has a synergistic regulatory effect on the optical properties. In the examples, the core layer forms a rigid skeleton through a cross-linked network of bisphenol A unsaturated polyester (UPGF-90) and polybutylene succinate (PBS), and its glass microbeads (15-45 μm) and nano-cerium oxide (0.4-0.8 μm) achieve directional scattering of light through refractive index matching (core layer resin refractive index 1.56, glass microbeads 1.52). At the same time, nano-cerium oxide absorbs energy in the ultraviolet band (200-400 nm), inhibits photodegradation, and ensures long-term transmittance retention (90.8%-93.5%). In contrast, in Comparative Example 1 (without core layer), due to the lack of this structure, when light directly penetrates the middle layer, Fresnel reflection loss occurs due to the difference between the PET / PBT matrix (refractive index 1.57) and the air interface (refractive index 1.0), causing the transmittance to drop to 78.3%. At the same time, due to the lack of the UV shielding effect of nano-cerium oxide, the transmittance retention rate after long-term wet and hot aging is only 68.5%.

[0029] The notched impact strength and flexural strength of Examples 1-4 are significantly better than those of Comparative Examples 1-3. This is presumably due to the synergistic toughening mechanism at the interface between the core layer and the intermediate layer. The PBS in the core layer acts as an elastic phase, dispersing the impact energy through molecular chain entanglement, while the maleic anhydride-grafted SEBS (grafting rate ≥1.5%) in the intermediate layer reacts with the anhydride groups and the hydroxyl groups at the end of PET / PBT to form chemical bonds, thereby enhancing the interfacial bonding between the glass fiber (ECS303-3H) and the resin and inhibiting crack propagation. Taking Example 2 as an example, the PBS content is increased to 15 parts, and its plasticizing effect increases the impact strength to 51.2 kJ / m². However, in Comparative Example 3, since the core layer and the surface layer are completely missing and only the physical reinforcement of the intermediate layer glass fiber (5-8 parts) is relied upon, there is a weak bonding area at the interface between the glass fiber and the resin, and stress concentration results in a flexural strength of only 72 MPa. The heat deformation temperatures of Examples 1-4 were significantly higher than those of Comparative Examples 1-3. This is because the rigid benzene ring structure and cross-linked network (DCP-induced free radical cross-linking) of the bisphenol A resin in the core layer restrict molecular chain motion, while the phosphorus-based flame retardant (resorcinol bisphosphate) in the middle layer generates a phosphate char layer during combustion, isolating oxygen and catalyzing the dehydration of PET / PBT into carbon, achieving UL94 V-0 flame retardancy. However, in Comparative Example 1, which lacks a core layer, the char layer is incomplete when the middle layer flame retardant acts alone. During vertical combustion, the molten droplets ignite cotton wool, resulting in a mere V-2 flame retardancy. Comparative Example 3 even failed the flame retardancy test.

[0030] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A composite heat-resistant diffusion plate, characterized in that: From bottom to top, it includes core layer, middle layer and surface layer; The core layer comprises the following components by mass: 40-50 parts of bisphenol A type unsaturated polyester, 10-20 parts of polybutylene succinate, 5-7 parts of glass microspheres, 1.2-1.5 parts of dicumyl peroxide, 3-5 parts of nano cerium oxide, and 0.8-1 part of kaolin; The intermediate layer comprises the following components in parts by mass: 55-60 parts of polyethylene terephthalate, 30-40 parts of polybutylene terephthalate, 1.5-2 parts of titanate coupling agent, 5-8 parts of chopped glass fiber, 5-7 parts of phosphorus flame retardant, and 0.5-1 part of maleic anhydride grafted SEBS; The surface layer comprises the following components by mass: 30-40 parts of polyethylene terephthalate-1,4-cyclohexanedimethanol, 3-5 parts of nano boron nitride, 8-10 parts of silicone-based light diffuser, 1.5-2 parts of antioxidant, and 3.5-4 parts of modified compatibilizer.

2. The composite heat-resistant diffusion plate according to claim 1, characterized in that: The maleic anhydride grafted SEBS is prepared by the following steps: S11. 80-100 parts by mass of SEBS are dissolved in 500-600 parts by mass of a toluene solution having a concentration of 10-20%, and stirred to form a uniform solution; S12. To the solution treated in step S11, 5-8 parts of maleic anhydride and 0.3-1 parts of benzoyl peroxide were added sequentially, stirred, and heated in an oil bath under nitrogen to 110-130 ° C. for 3-6 hours to obtain a reaction solution; S13. The reaction solution was treated with acetone to precipitate a polymer, which was washed with ethanol 3-4 times and dried under vacuum at 60-80° C. to a constant weight to obtain the maleic anhydride-grafted SEBS.

3. The composite heat-resistant diffusion plate according to claim 1, characterized in that: The modified compatibilizer is prepared by the following steps: S21. 60-80 parts by mass of ethylene - vinyl acetate copolymer was dissolved in 400-500 parts by mass concentration of 10-20% toluene solution, and stirred to form a uniform solution; S22. To the solution treated in step S21, 5-8 parts of glycidyl methacrylate and 0.5-1.5 parts of benzoyl peroxide were added sequentially, stirred, and heated in an oil bath under nitrogen to 110-130 ° C. for 4-8 hours to obtain a modified compatibilizer solution; S23. The modified compatibilizer solution is treated with methanol to precipitate a polymer, which is washed with ethanol 3-4 times and dried under vacuum at 60-80° C. to a constant weight to obtain the modified compatibilizer.

4. The composite heat-resistant diffusion plate according to claim 1, characterized in that: The particle size of the glass microbeads is 15-45 μm; the particle size of the kaolin is 1.5-3 μm.

5. The composite heat-resistant diffusion plate according to claim 1, characterized in that: The titanate coupling agent is further defined as a monoalkoxy pyrophosphate type coupling agent.

6. The composite heat-resistant diffusion plate according to claim 1, characterized in that: The fiber length of the chopped glass fibers is 2.5-3.5 mm, and the diameter is 10-13 μm; the phosphorus-based flame retardant is further limited to a phosphate flame retardant.

7. The composite heat-resistant diffusion plate according to claim 1, characterized in that: The silicone-based light diffuser is further defined as an organosilicon composite light diffuser; the antioxidant is selected from one or more of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate and octadecylβ-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate.

8. A process for preparing a composite heat-resistant diffusion plate, for producing the composite heat-resistant diffusion plate according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1. Premixing of raw materials: The raw materials of the core layer, the middle layer, and the surface layer are respectively put into a high-pressure mixer and mixed and stirred for 10-20 minutes to obtain the corresponding core layer premix, the middle layer premix, and the surface layer premix; S2 extrusion granulation: the core layer premix, the intermediate layer premix were extruded through a twin-screw extruder granulation, the surface premix was extruded through a single-screw extruder granulation to obtain core particles, intermediate layer particles, surface particles; S3. Imprinting molding: The core layer particles and the middle layer particles are respectively put into a twin-screw extruder, and the surface layer particles are put into a single-screw extruder for heating and melting. The three layers are co-extruded and imprinted to obtain the composite heat-resistant diffusion plate.

9. The process for preparing a composite heat-resistant diffusion plate according to claim 8, characterized in that: In step S2, the temperature of each zone of the twin-screw extruder used to prepare the core layer particles is: 160-180°C in the first zone, 190-200°C in the second zone, 210-220°C in the third zone, and the die head temperature is 215-220°C; The temperatures of each zone of the twin-screw extruder used to prepare the intermediate layer particles are: 240-250°C in the first zone, 260-270°C in the second zone, 260-265°C in the third zone, and 265-270°C in the die head. The temperatures of each zone of the single-screw extruder used to prepare the surface layer particles are: 200-210°C in the first zone, 220-230°C in the second zone, 230-240°C in the third zone, and 225-230°C in the die head.

10. The process for preparing a composite heat-resistant diffusion plate according to claim 8, characterized in that: In step S3, the temperature of each zone of the twin-screw extruder for melting the core layer particles is: 190-200°C in the first zone, 210-220°C in the second zone, and 205-210°C in the die head; The temperature of each zone of the twin-screw extruder used for melting the intermediate layer particles is: 260-270°C in the first zone, 275-280°C in the second zone, and 265-270°C in the die head; The temperatures of each zone of the single-screw extruder used for melting the surface layer particles are: 220-230°C in the first zone, 235-240°C in the second zone, and 235-240°C in the die head.

Images