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CN-121115189-B - Composite optical diffusion plate and preparation method thereof

CN121115189BCN 121115189 BCN121115189 BCN 121115189BCN-121115189-B

Abstract

The invention relates to the technical field of preparation of optical diffusion plates, in particular to a composite optical diffusion plate and a preparation method thereof. The optical diffusion plate sequentially comprises an upper layer A, a functional layer B, a core layer C, a functional layer D and a lower layer E from top to bottom, and the low-warpage performance and the light diffusion performance of the plate are remarkably improved through multilayer composite design. Each layer adopts polyester matrix, functional filler, chain extender, antioxidant, ultraviolet absorber and the like with different types and proportions to realize high light transmittance, high light diffusion and excellent dimensional stability in a synergistic way. The optical diffusion plate prepared by the invention adopts multi-step premixing, double-screw coextrusion and sectional annealing cooling processes, so that residual stress can be effectively released, and buckling deformation can be further inhibited. The scheme has reasonable structure, scientific formula and excellent mechanical property, weather resistance and processing adaptability of the product, and is suitable for manufacturing the optical diffusion plate in the fields of high-end illumination, display and the like.

Inventors

  • WANG XIAOHONG
  • Ling Gaode
  • WANG XINGLI
  • LIANG MANYI

Assignees

  • 广东瑞捷新材料股份有限公司

Dates

Publication Date
20260512
Application Date
20250922

Claims (9)

  1. 1. The composite optical diffusion plate is characterized by comprising an upper layer A, a functional layer B, a core layer C, a functional layer D and a lower layer E from top to bottom in sequence; the upper layer A and the lower layer E comprise, by mass, 85-90 parts of polyethylene terephthalate-1, 4-cyclohexanedimethanol ester copolymer, 10-15 parts of polyethylene terephthalate, 0.5-1 part of BOZ chain extender, 0.3-0.5 part of carbodiimide, 0.12-0.15 part of antioxidant, 0.35-0.5 part of ultraviolet absorber, 0.8-1.2 parts of transparent micelle and 0.08-0.1 part of lubricant; The functional layer B and the functional layer D comprise, by mass, 50-60 parts of polyethylene terephthalate-1, 4-cyclohexanedimethanol ester copolymer, 15-20 parts of polyethylene terephthalate, 6-10 parts of polybutylene terephthalate, 4-8 parts of polybutylene succinate, 3-5 parts of PCT (polyethylene terephthalate) oligoester, 0.8-1.2 parts of transparent micelles, 0.3-0.5 part of nano SiO 2 , 0.4-0.5 part of glass microspheres, 0.6-0.8 part of BOZ chain extender, 0.25-0.3 part of carbodiimide, 0.12-0.15 part of antioxidant and 0.25-0.3 part of ultraviolet absorber; 55-60 parts of polyethylene terephthalate-1, 4-cyclohexanedimethanol ester copolymer, 20-25 parts of polyethylene terephthalate, 4-5 parts of polybutylene terephthalate, 3-5 parts of polybutylene succinate, 1-3 parts of PCT (low temperature polyethylene) oligoester, 2.8-4 parts of polymethyl methacrylate coated silica microspheres, 0.5-1 part of transparent micelle, 0.4-0.5 part of nano SiO 2 , 0.4-0.5 part of BOZ chain extender, 0.25-0.3 part of carbodiimide, 0.12-0.15 part of antioxidant, 0.35-0.5 part of ultraviolet absorber and 0.08-0.1 part of lubricant; the polymethyl methacrylate coated silica microsphere is prepared through the following steps: dispersing 20-30 parts of dry SiO 2 microspheres in 100-200 parts of deionized water by mass, adding 0.5-1wt% of sodium dodecyl sulfate, uniformly stirring, adjusting the pH value to 7-8, dropwise adding 10-15 parts of methyl acrylate monomer, and mixing and stirring for 10-15min; And secondly, introducing nitrogen for 20-30min for oxygen removal, heating to 65-70 ℃, adding 0.5-1wt% of K 2 S 2 O 8 , reacting for 3-4h under the protection of nitrogen, cooling to room temperature, taking out the product, centrifuging, washing and drying to obtain the polymethyl methacrylate coated silica microsphere.
  2. 2. A composite optical diffuser plate as set forth in claim 1 wherein said carbodiimide is further defined as an aromatic carbodiimide.
  3. 3. A composite optical diffuser plate according to claim 1 wherein said transparent micelles are further defined as PVC transparent micelles.
  4. 4. The composite optical diffuser plate of claim 1 wherein the glass microspheres have a particle size of 15-45 μm.
  5. 5. The composite optical diffusion plate according to claim 1, wherein the antioxidant is a mixture of phenolic antioxidants and phosphite antioxidants in a mass ratio of 1:2, the lubricant is a stearic lubricant, and the ultraviolet absorber is a benzophenone ultraviolet absorber.
  6. 6. A method for preparing the composite optical diffusion plate according to any one of claims 1 to 5, comprising the steps of: s1, respectively adding raw materials of an upper layer, a lower layer, a functional layer and a core layer into a high-speed mixer according to parts by weight, mixing and stirring for 20-30min, and premixing to obtain corresponding upper layer premix, lower layer premix, functional layer premix and core layer premix; S2, respectively extruding the upper layer premix, the lower layer premix, the functional layer premix and the core layer premix through a double-screw extruder, and carrying out water-cooling bracing and air drying on the extrudate to obtain an upper layer master batch, a lower layer master batch, a functional layer master batch and a core layer master batch; S3, putting the upper layer master batch, the lower layer master batch, the functional layer master batch and the core layer master batch into a double-screw extruder for heating and melting, and performing coextrusion and embossing molding by utilizing five-layer distribution blocks and a T-shaped die to obtain a pre-composite optical diffusion plate; s4, placing the pre-composite optical diffusion plate in a circulating hot blast stove, preserving heat for 25-30min at 68-70 ℃, heating to 80-83 ℃, preserving heat for 20-25min, and finally slowly cooling to room temperature at 0.5-0.8 ℃ per min to obtain the composite optical diffusion plate.
  7. 7. The method according to claim 6, wherein in the step S2, the temperatures of the two-screw extruder for preparing the upper layer master batch and the lower layer master batch are 180-200 ℃, 210-220 ℃, 225-235 ℃, 235-240 ℃ and 245-250 ℃ in the first zone, 255-260 ℃ in the third zone and 255-260 ℃ in the die head; The temperature of each zone of the twin-screw extruder for preparing the functional layer master batch is 180-200 ℃, 215-225 ℃, 230-240 ℃, 245-250 ℃ and 250-260 ℃ in the third zone and 265-270 ℃ in the fifth zone; The temperature of each zone of the twin-screw extruder for preparing the core layer master batch is 180-200 ℃, the temperature of the second zone is 230-240 ℃, the temperature of the third zone is 240-245 ℃, the temperature of the fourth zone is 245-250 ℃, the temperature of the fifth zone is 255-260 ℃ and the temperature of the die head is 265-270 ℃.
  8. 8. The method according to claim 6, wherein in the step S3, the temperatures of the two-screw extruder for melting the upper-layer master batch and the lower-layer master batch are 220-230 ℃, 240-245 ℃, 245-250 ℃ and 255-260 ℃ in the first zone; The temperature of each zone of the twin-screw extruder for melting the functional layer master batch is 235-240 ℃, the temperature of the first zone is 245-250 ℃, the temperature of the third zone is 255-260 ℃ and the temperature of the die head is 255-260 ℃; the temperature of each zone of the single screw extruder for melting the core layer masterbatch is 230-235 ℃, the second zone is 245-250 ℃, the third zone is 255-260 ℃, and the die temperature is 260-270 ℃.
  9. 9. The method of claim 6, wherein the layer thicknesses of the upper layer A, the functional layer B, the core layer C, the functional layer D and the lower layer E are 10-15:15-20:50-60:15-20:10-15.

Description

Composite optical diffusion plate and preparation method thereof Technical Field The invention relates to the technical field of preparation of optical diffusion plates, in particular to a composite optical diffusion plate and a preparation method thereof. Background With the continuous progress of technology and the acceleration of global market progress, market competition in the field of backlight modules of liquid crystal displays is increasing. The quality and performance of the optical diffusion plate, which is used as an optical element of the backlight module, directly affect the brightness uniformity, the picture definition and the service life of the whole product of the display terminal. In order to occupy an advantage in strong market competition, manufacturers generally take various measures such as reducing production cost, optimizing product structure, improving processing efficiency and the like so as to realize the dual advantages of finished product price and performance. Meanwhile, the problem of physical deformation of the optical diffusion plate, especially the warp deformation generated during the use and storage process, has become a key bottleneck for restricting the quality improvement and the large-scale application of the backlight module of the liquid crystal display. In the prior art, in order to suppress the warpage phenomenon of the optical diffusion plate, a method of coating or coating the upper and lower surfaces of the substrate is generally adopted, and internal stress is balanced by forming a symmetrical structure. However, this type of approach has significant drawbacks. Firstly, the coating and film covering process steps are complicated, the production flow is longer, the equipment investment and the labor cost are increased, and the large-scale and low-cost production is not facilitated. And secondly, the bonding strength between the coating and the substrate is limited, and interfacial peeling or microcracks are easily generated due to environmental temperature and humidity changes, so that the performance and the service life of the product are reduced. In addition, the thermal expansion coefficient between the partial coating material and the polymer matrix is poor in matching, and new warping and deformation problems are easy to occur after temperature cycle or long-term use. Meanwhile, the single-layer structure or the simple double-layer structure of the traditional optical diffusion plate cannot fully disperse and release internal stress in the forming or using process, so that the material is easy to permanently warp when being subjected to external stress, and strict requirements of a high-end display terminal on dimensional stability and optical uniformity are difficult to meet. Therefore, how to develop a composite optical diffusion plate with more reasonable structure and more excellent performance becomes a technical hot spot and a difficult problem in the field of the backlight module of the current liquid crystal display. Disclosure of Invention In order to overcome the defects in the prior art, the invention aims to provide a composite optical diffusion plate and a preparation method thereof. The optical diffusion plate sequentially comprises an upper layer A, a functional layer B, a core layer C, a functional layer D and a lower layer E from bottom to top, and the low-warpage performance and the light diffusion performance of the plate are remarkably improved through multilayer composite design. Each layer adopts polyester matrix, functional filler, chain extender, antioxidant, ultraviolet absorber and the like with different types and proportions to realize high light transmittance, high light diffusion and excellent dimensional stability in a synergistic way. The optical diffusion plate prepared by the invention adopts multi-step premixing, double-screw coextrusion and sectional annealing cooling processes, so that residual stress can be effectively released, and buckling deformation can be further inhibited. The scheme has reasonable structure, scientific formula and excellent mechanical property, weather resistance and processing adaptability of the product, and is suitable for manufacturing the optical diffusion plate in the fields of high-end illumination, display and the like. In order to achieve the above purpose, the present invention provides the following technical solutions: A composite optical diffusion plate, which sequentially comprises an upper layer A, a functional layer B, a core layer C, a functional layer D and a lower layer E from top to bottom; the upper layer A and the lower layer E comprise, by mass, 85-90 parts of polyethylene terephthalate-1, 4-cyclohexanedimethanol ester copolymer, 10-15 parts of polyethylene terephthalate, 0.5-1 part of BOZ chain extender, 0.3-0.5 part of carbodiimide, 0.12-0.15 part of antioxidant, 0.35-0.5 part of ultraviolet absorber, 0.8-1.2 parts of transparent micelle and 0.08-0.1 part of lubricant;