Adjustable composite homogenizing film applied to display and production process thereof

Abstract

The application discloses a kind of adjustable composite light uniformizing film applied to display and production process thereof, belong to optical film technical field.A kind of adjustable composite light uniformizing film applied to display, including prism layer, the substrate layer is equipped under the prism layer, substrate layer is equipped with back coating layer;The prism layer and back coating layer use modified PMMA resin.The modified PMMA resin used in the application is made by the following steps: methyl methacrylate, nano montmorillonite and hydroxyethyl cellulose are added into ethanol, ultrasonic dispersion is 1h, nitrogen is introduced, stirring is 1-2h, potassium persulfate is added to react for 6h, methanol is added, and is placed for 0.5h, water washing is extracted and filtered, and modified PMMA resin is obtained after drying.The modified PMMA resin used in the application has better thermal stability and mechanical properties, expands its application range in the production process of light uniformizing film, and further improves the production efficiency of light uniformizing film.

Description

Technical Field

[0001] This invention belongs to the field of optical film technology, specifically relating to an adjustable composite light-diffusing film for displays and its manufacturing process. Background Technology

[0002] With the continuous advancement of display technology, the display effect of display devices needs to be constantly optimized. LED lights are widely used due to their long lifespan and low energy consumption. However, the LED beads inside are usually arranged at a certain interval, which causes a certain interval between light and dark. Moreover, the light emitted by them is often quite dazzling, and the overall light uniformity effect is poor, which cannot better meet the display needs of mini LED. In response to the problems in LED light source lighting, existing technologies have provided light uniformity films, which can effectively solve the shortcomings of LED light such as dazzling light and uneven light distribution.

[0003] The function of a light-diffusing film is to diffuse the passing light to achieve a uniform light distribution. Existing light-diffusing films mainly involve coating a resin layer with scattering particles onto a transparent substrate layer, and then using rollers to roll the resin layer to form specific textures. The surface of the resin layer is then cured to form a rough layer. In this way, when light passes through the light-diffusing film, it will undergo many refractions, reflections, and scatterings within the rough layer between the scattering particles and the resin, which are two media with different refractive indices, to produce a uniform light distribution effect.

[0004] In the existing technology, the resin used in the production process of light-diffusing film is often polymethyl methacrylate (PMMA) resin, which has good mechanical properties and light transmittance; however, PMMA resin has poor heat resistance and wear resistance, which greatly limits its application range. Summary of the Invention

[0005] The purpose of this invention is to provide an adjustable composite light-diffusing film for use in displays and its manufacturing process, in order to solve the problems of poor heat resistance and mechanical properties of PMMA resin.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] An adjustable composite light-diffusing film for display applications includes a prism layer, a substrate layer below the prism layer, and a back coating layer below the substrate layer; the prism layer and the back coating layer are made of modified PMMA resin.

[0008] The modified PMMA resin described above is prepared through the following steps:

[0009] Step 1: Preparation of nano-montmorillonite:

[0010] Carboxyl-containing montmorillonite was added to distilled water and ultrasonically dispersed. Carbonimine hydrochloride and 3-amino-1,2,4-triazole were added and ultrasonically dispersed. The mixture was heated to 85°C and stirred for 2-3 hours. The pH was adjusted and stirred for 2-3 hours. The mixture was washed with water and dried to obtain nano-montmorillonite.

[0011] Step 2: Preparation of modified PMMA resin:

[0012] Methyl methacrylate (MMA), nano-montmorillonite, and hydroxyethyl cellulose were added to ethanol, ultrasonically dispersed for 1 hour, nitrogen gas was introduced, and the mixture was stirred for 1-2 hours. Potassium persulfate was added and reacted for 6 hours. Methanol was added, and the mixture was allowed to stand for 0.5 hours. After washing with water and filtration, the modified PMMA resin was obtained.

[0013] Preferably, the substrate layer is one of a PET layer and a PC layer.

[0014] Preferably, the ratio of carboxylated montmorillonite, distilled water, carbodiimide hydrochloride and 3-amino-1,2,4-triazole is 2g:400mL:0.75g:0.25g; wherein the pH is adjusted to 3-4.

[0015] Preferably, the ratio of methyl methacrylate (MMA), nano-montmorillonite, hydroxyethyl cellulose, ethanol, potassium persulfate and methanol is 10g:0.1-0.5g:0.01g:200mL:0.1g:30mL.

[0016] Preferably, carboxyl-containing montmorillonite is prepared by the following steps:

[0017] Montmorillonite was added to distilled water and ultrasonically dispersed for 1 hour. Then, cocamidopropyl betaine and hydrochloric acid solution were added, heated to 80°C and stirred for 4 hours. After standing for 0.5 hours, it was washed with water, filtered and dried, ground and sieved to obtain carboxyl-containing montmorillonite.

[0018] Preferably, the ratio of montmorillonite, distilled water, cocamidopropyl betaine, and hydrochloric acid solution is 4g:400mL:10g:3mL; wherein the mass fraction of cocamidopropyl betaine is 30%, and the mass fraction of hydrochloric acid solution is 10%.

[0019] The present invention also provides a manufacturing process for an adjustable composite light-diffusing film for use in displays, comprising the following steps:

[0020] Step A1: Apply a layer of modified PMMA resin to the lower surface of the substrate layer, perform sandblasting using a haze mold, and cure to form a back coating layer;

[0021] Step A2: Apply a layer of modified PMMA resin to the upper surface of the substrate layer, cut it using a prism mold, and cure it to form a prism layer.

[0022] Preferably, the haze of the back coating is 1-20%.

[0023] Preferably, the shape of the prism mold is one of a micro-circular shape, a micro-triangular pyramid shape, and a micro-quadrangular pyramid shape.

[0024] Preferably, the spacing between the micro-pyramidal shapes is controlled at 24-50 μm.

[0025] The beneficial effects of this invention are:

[0026] This invention discloses an adjustable composite light-diffusing film for displays, which utilizes a self-made modified PMMA resin in its production process. During the preparation of this modified PMMA resin, surface-modified nano-montmorillonite is added, allowing for better dispersion of the nano-montmorillonite within the PMMA resin. The surface-modified nano-montmorillonite incorporates hydrogen-bonding structural units (triazole groups) on its surface, forming multiple hydrogen bonds with the PMMA resin. This facilitates force transfer between components. Hydrogen bonds are temperature-sensitive, capable of breaking and generating energy loss upon temperature changes, thus better adapting to varying environmental temperatures and exhibiting excellent thermal stability. The addition of nano-montmorillonite to the PMMA resin enhances its thermal stability and abrasion resistance, while also improving its hardness and dimensional stability, enabling the PMMA resin to play a more effective role in the production process of the light-diffusing film.

[0027] In the process of producing the light-diffusing film, the present invention uses a micro-structured prism mold, which makes the diffraction effect more obvious and the prepared light-diffusing film has better optical effect; the prism layer made by the micro quadrangular mold can improve retroreflectivity by changing the spacing, and further improve the reflective brightness and uniformity of the light-diffusing film. Detailed Implementation

[0028] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0029] Example 1

[0030] This embodiment provides an adjustable composite light-diffusing film for use in displays:

[0031] Preparation of carboxyl-containing montmorillonite:

[0032] Add 4g of montmorillonite to 400mL of distilled water and sonicate for 1h. Add 10mL of cocamidopropyl betaine (30% by mass) and 3mL of hydrochloric acid solution (10% by mass). Heat to 80℃ and stir for 4h. Let stand for 0.5h. Wash three times with distilled water, filter, dry in a 60℃ oven, grind, and pass through a 300-mesh sieve to obtain carboxyl-containing montmorillonite.

[0033] Step 1: Preparation of nano-montmorillonite:

[0034] Add 2g of carboxyl-containing montmorillonite to 300mL of distilled water and sonicate for 1h. Add 0.75g of carbodiimide hydrochloride and 0.25g of 3-amino-1,2,4-triazole and sonicate for 0.5h. Heat to 85℃ and stir for 2h. Adjust the pH to 4 and stir for 3h. Wash three times with distilled water and dry in a vacuum oven at 50℃ for 24h to obtain nano-montmorillonite.

[0035] Step 2: Preparation of modified PMMA resin:

[0036] 10g MMA, 0.1g nano-montmorillonite, and 0.01g hydroxyethyl cellulose were added to 200mL ethanol and ultrasonically dispersed for 1h. Nitrogen gas was introduced for 0.5h, and the mixture was stirred for 1h. 0.1g potassium persulfate was added and reacted for 6h. 30mL methanol was added, and the mixture was allowed to stand for 0.5h. The mixture was washed three times with distilled water, filtered, and then placed in a vacuum drying oven at 50℃ for 24h to obtain modified PMMA resin.

[0037] Example 2

[0038] The only difference from Example 1 is that:

[0039] Step 2: Preparation of modified PMMA resin:

[0040] 10g MMA, 0.2g nano-montmorillonite, and 0.01g hydroxyethyl cellulose were added to 200mL ethanol and ultrasonically dispersed for 1h. Nitrogen gas was introduced for 0.5h, and the mixture was stirred for 1h. 0.1g potassium persulfate was added and reacted for 6h. 30mL methanol was added, and the mixture was allowed to stand for 0.5h. The mixture was washed three times with distilled water, filtered, and then placed in a vacuum drying oven at 50℃ for 24h to obtain modified PMMA resin.

[0041] Example 3

[0042] The only difference from Example 1 is that:

[0043] Step 2: Preparation of modified PMMA resin:

[0044] 10g MMA, 0.3g nano-montmorillonite, and 0.01g hydroxyethyl cellulose were added to 200mL ethanol and ultrasonically dispersed for 1h. Nitrogen gas was introduced for 0.5h, and the mixture was stirred for 1h. 0.1g potassium persulfate was added and reacted for 6h. 30mL methanol was added, and the mixture was allowed to stand for 0.5h. The mixture was washed three times with distilled water, filtered, and then placed in a vacuum drying oven at 50℃ for 24h to obtain modified PMMA resin.

[0045] Example 4

[0046] The only difference from Example 1 is that:

[0047] Step 2: Preparation of modified PMMA resin:

[0048] 10g MMA, 0.4g nano-montmorillonite, and 0.01g hydroxyethyl cellulose were added to 200mL ethanol and ultrasonically dispersed for 1h. Nitrogen gas was introduced for 0.5h, and the mixture was stirred for 1h. 0.1g potassium persulfate was added and reacted for 6h. 30mL methanol was added, and the mixture was allowed to stand for 0.5h. The mixture was washed three times with distilled water, filtered, and then placed in a vacuum drying oven at 50℃ for 24h to obtain modified PMMA resin.

[0049] Example 5

[0050] The only difference from Example 1 is that:

[0051] Step 2: Preparation of modified PMMA resin:

[0052] 10g MMA, 0.5g nano-montmorillonite, and 0.01g hydroxyethyl cellulose were added to 200mL ethanol and ultrasonically dispersed for 1h. Nitrogen gas was introduced for 0.5h, and the mixture was stirred for 1h. 0.1g potassium persulfate was added and reacted for 6h. 30mL methanol was added, and the mixture was allowed to stand for 0.5h. The mixture was washed three times with distilled water, filtered, and then placed in a vacuum drying oven at 50℃ for 24h to obtain modified PMMA resin.

[0053] Comparative Example 1

[0054] Pure PMMA resin.

[0055] Example 6

[0056] This embodiment provides a manufacturing process for an adjustable composite light-diffusing film applied to a display:

[0057] A homogenizing film was prepared using the modified PMMA resin from Example 1:

[0058] Step A1: Coat the lower surface of the substrate layer with a layer of modified PMMA resin, perform sandblasting using a haze mold with 3% haze, and dry at 80°C for 3 minutes to form a back coating.

[0059] Step A2: Coat the upper surface of the substrate layer with a layer of modified PMMA resin, cut it using a micro prism mold with a spacing of 26μm, and dry it at 80℃ for 3 minutes to form a prism layer; thus obtaining a uniform light film.

[0060] Example 7

[0061] The only difference from Example 6 is that the haze of the haze mold is 7%; the spacing of the micro prism mold is 35 μm, resulting in a uniform light film.

[0062] Example 8

[0063] The only difference from Example 6 is that the modified PMMA resin in Example 2 was used to prepare the uniform light film; the haze of the haze mold was 13%; and the spacing of the micro prism mold was 40 μm to obtain the uniform light film.

[0064] Example 9

[0065] The only difference from Example 6 is that the modified PMMA resin in Example 2 was used to prepare the uniform light film; the haze of the haze mold was 16%; and the spacing of the micro prism mold was 45 μm to obtain the uniform light film.

[0066] Example 10

[0067] The only difference from Example 6 is that the modified PMMA resin in Example 2 was used to prepare the uniform light film; the haze of the haze mold was 19%; and the spacing of the micro prism mold was 48 μm, thus obtaining the uniform light film.

[0068] Performance tests were conducted on Examples 1-5 and Comparative Example 1:

[0069] Mechanical property testing: The modified PMMA resin mechanical specimens were subjected to tensile and flexural property tests using an M350-20KN universal testing machine. The tensile rate was 2 mm / min, the flexural support span was L = 65 mm, and the indenter test speed was 2 mm / min.

[0070] Hardness test: After hot pressing, the hardness of the material was measured on an XHRD-150 electric Rockwell hardness tester. Test conditions: initial test pressure 98N, total test pressure 588N, steel ball indenter diameter 6.35mm, holding time 6S.

[0071] Thermogravimetric analysis: The modified PMMA resin was subjected to TG analysis on a thermogravimetric-differential thermal analyzer at a heating rate of 10℃ / min and a temperature range of 25-800℃. The residual weight percentage was calculated at the same time.

[0072] The test results are shown in Table 1:

[0073] Table 1

[0074]

[0075] As can be seen from Table 1, the tensile strength, elongation at break, and flexural strength of Examples 1-5 are all higher than those of Comparative Example 1, indicating that the modified PMMA resin prepared by this invention has better mechanical properties. Compared with Comparative Example 1, Examples 1-5 have higher hardness. As can be seen from the temperature at which the weight loss rate is 50%, the thermal stability of Examples 1-5 is higher than that of Comparative Example 1, indicating that the modified PMMA resin has higher thermal stability and better mechanical properties than pure PMMA resin.

[0076] The performance of the homogenizing films prepared in Examples 6-10 was tested, and the test results are shown in Table 2:

[0077] Table 2

[0078]

[0079] As can be seen from Table 2, the U values ​​in Examples 6-10 are all relatively high, which shows that the light-diffusing film prepared by the present invention has good optical effects and light-diffusing performance.

[0080] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0081] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A composite light-diffusing film for a display, comprising a prism layer, a substrate layer beneath the prism layer, and a back coating layer beneath the substrate layer, characterized in that, The prism layer and the back coating are made of modified PMMA resin; the modified PMMA resin is prepared by the following steps: Step 1: Preparation of nano-montmorillonite: Carboxyl-containing montmorillonite was added to distilled water and ultrasonically dispersed. Carbonimine hydrochloride and 3-amino-1,2,4-triazole were added and ultrasonically dispersed. The mixture was heated to 85°C and stirred for 2-3 hours. The pH was adjusted and stirred for 2-3 hours. The mixture was then washed with water and dried to obtain nano-montmorillonite. Step 2: Preparation of modified PMMA resin: Methyl methacrylate, nano-montmorillonite, and hydroxyethyl cellulose were added to ethanol and ultrasonically dispersed for 1 hour. Nitrogen gas was introduced and the mixture was stirred for 1-2 hours. Potassium persulfate was added and reacted for 6 hours. Methanol was added and the mixture was allowed to stand for 0.5 hours. After washing with water and filtration, the modified PMMA resin was obtained after drying.

2. The composite light-diffusing film for a display according to claim 1, characterized in that, The substrate layer is either a PET layer or a PC layer.

3. The composite light-diffusing film for a display according to claim 1, characterized in that, The ratio of carboxylated montmorillonite, distilled water, carbodiimide hydrochloride, and 3-amino-1,2,4-triazole is 2g:400mL:0.75g:0.25g; the pH is adjusted to 3-4.

4. The composite light-diffusing film for a display according to claim 1, characterized in that, The ratio of methyl methacrylate, nano-montmorillonite, hydroxyethyl cellulose, ethanol, potassium persulfate and methanol is 10g:0.1-0.5g:0.01g:200mL:0.1g:30mL.

5. A composite light-diffusing film for a display according to claim 1, characterized in that, Carboxyl-containing montmorillonite is prepared through the following steps: Montmorillonite was added to distilled water and ultrasonically dispersed for 1 hour. Then, cocamidopropyl betaine and hydrochloric acid solution were added, heated to 80°C and stirred for 4 hours. After standing for 0.5 hours, it was washed with water, filtered and dried, ground and sieved to obtain carboxyl-containing montmorillonite.

6. A composite light-diffusing film for a display according to claim 5, characterized in that, The ratio of montmorillonite, distilled water, cocamidopropyl betaine, and hydrochloric acid solution was 4g:400mL:10g:3mL; wherein the mass fraction of cocamidopropyl betaine was 30% and the mass fraction of hydrochloric acid solution was 10%.

7. The manufacturing process of a composite light-diffusing film for a display according to claim 1, characterized in that, Includes the following steps: Step A1: Apply a layer of modified PMMA resin to the lower surface of the substrate layer, perform sandblasting using a haze mold, and cure to form a back coating layer; Step A2: Apply a layer of modified PMMA resin to the upper surface of the substrate layer, cut it using a prism mold, and cure it to form a prism layer.

8. The manufacturing process of a composite light-diffusing film for a display according to claim 7, characterized in that, The haze of the back coating is 1-20%.

9. The manufacturing process of a composite light-diffusing film for a display according to claim 7, characterized in that, The prism mold can be one of the following shapes: micro-circular, micro-triangular pyramidal, or micro-quadrangular pyramidal.

10. The manufacturing process of a composite light-diffusing film for a display according to claim 9, characterized in that, The spacing of the micro-pyramidal shapes is controlled between 24-50 μm.

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