Black light-shielding cover film and method for manufacturing the same

Abstract

The application provides a black light-shielding covering film and a preparation method thereof, and relates to the field of light-shielding parts of electronic products.The black light-shielding covering film comprises a PI film and a release film, and a black epoxy glue layer coated between the PI film and the release film, wherein the black epoxy glue layer is composed of butyronitrile rubber, composite epoxy resin, reinforcing filler, carbon black, flame retardant, curing agent, catalyst and antioxidant; the composite epoxy resin is obtained by mixing DCPD epoxy resin and NPES-901 epoxy resin at a mass ratio of 2-3:1; and the reinforcing filler is obtained by mixing modified hydroxide aluminum and zeolite with a titanate coupling agent at a mass ratio of 1-3:1.The application overcomes the shortcomings of the prior art, effectively guarantees the adhesion effect of the substrate layer and the release layer, guarantees the light-shielding property of the light-shielding film, further improves the mechanical property of the overall light-shielding film, and comprehensively improves the application value of the product.

Description

Technical Field

[0001] This invention relates to the field of light-shielding components for electronic products, and specifically to a black light-shielding covering film and its preparation method. Background Technology

[0002] Electronic product light-shielding film is a material used to package electronic products, precision instruments, or other products that need to be protected from light. Its main function is to prevent the product from changing its properties when exposed to light. Light-shielding film is widely used in products such as mobile phones, tablets, laptops, PDAs, LEDs, and LCDs for light shielding and reflection. It is also used in products such as backlit keyboards, ultra-thin advertising light boxes, and backlight panels (films).

[0003] Traditionally, black and white light-blocking tape is used as a light-blocking film. However, with the popularization and upgrading of electronic products, the demand for light-blocking films is constantly increasing. At present, most light-blocking films are made by coating adhesive between the substrate and the release film, which can effectively improve the stability and durability of the light-blocking film.

[0004] The durability and reliability of light-blocking films in practical applications are mainly reflected in mechanical properties such as tensile strength and elongation at break. Therefore, based on existing technologies, improving the mechanical properties of light-blocking films while ensuring their basic performance is the main research and development direction at this stage. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a black light-blocking cover film and its preparation method. While effectively ensuring the adhesion effect of the substrate layer and the release layer, it also ensures the light-blocking properties of the light-blocking film, further improving the overall mechanical properties of the light-blocking film and comprehensively enhancing the application value of the product.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A black light-shielding covering film, comprising a PI film and a release film, and a black epoxy adhesive layer coated between the PI film and the release film, wherein the black epoxy adhesive layer is made of the following raw materials in parts by weight: 20-25 parts nitrile rubber, 32-38 parts composite epoxy resin, 12-16 parts reinforcing filler, 12-17 parts carbon black, 6-8 parts flame retardant, 2-3 parts curing agent, 0.2-0.4 parts catalyst, and 0.5-0.8 parts antioxidant; wherein the composite epoxy resin is obtained by mixing DCPD epoxy resin (dicyclopentadiene phenol epoxy resin) and NPES-901 epoxy resin (low molecular weight solid bisphenol A type epoxy resin) in a mass ratio of 2-3:1; wherein the reinforcing filler is obtained by mixing graded particle size aluminum hydroxide modified with titanate coupling agent and zeolite in a mass ratio of 1-3:1.

[0008] Preferably, the specific preparation method of the reinforcing filler includes the following steps:

[0009] S1-1. Mix aluminum hydroxide with a particle size of 1-10 nm, aluminum hydroxide with a particle size of 0.2-0.5 μm, and aluminum hydroxide with a particle size of 5-15 μm in a mass ratio of 1:5:2 until homogeneous, and then sort the aluminum hydroxide by particle size for later use.

[0010] S1-2. Dissolve 3%-5% of the total mass of graded aluminum hydroxide in an ethanol solution to prepare a coupling agent solution for later use.

[0011] S1-3. Pour the graded aluminum hydroxide into the coupling agent solution, stir continuously for 2 hours in an oil bath at 80°C, then centrifuge, and vacuum dry the precipitate to obtain modified aluminum hydroxide for later use.

[0012] S1-4. Mix modified aluminum hydroxide and zeolite at a mass ratio of 1-3:1 and grind them evenly to obtain the reinforcing filler.

[0013] Preferably, the flame retardant is at least one of zinc borate or barium metaborate.

[0014] Preferably, the curing agent is at least one selected from 4,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenylmethane, and 3,3'-diethyl-4,4'-diaminodiphenylmethane.

[0015] Preferably, the catalyst is dicyandiamide.

[0016] Preferably, the antioxidant is at least one of antioxidant B215, antioxidant 1076, and antioxidant 1010.

[0017] The preparation method of the black light-blocking coating film includes the following steps:

[0018] (1) Mix nitrile rubber and butanone at a mass ratio of 1:4 and dissolve them to prepare a rubber liquid;

[0019] (2) Take 1 / 2 of the rubber liquid prepared in step (1) above, add it together with the reinforcing filler and flame retardant into methyl ethyl ketone and stir for 2-4 hours, then grind it to obtain the mother liquor for later use;

[0020] (3) Mix the mother liquor, the remaining rubber liquid, carbon black, composite epoxy resin, curing agent, catalyst and antioxidant evenly to make black epoxy glue for later use.

[0021] (4) Apply black epoxy adhesive to the surface of PI film, bake and cure it at high temperature in a tunnel oven, then apply release film on top of black epoxy adhesive, and roll it up after pressing to obtain black light-blocking cover film.

[0022] Preferably, in step (2), the stirring speed is 400-700 r / min, and the grinding process is to place the mixture in a sand mill and grind it 2-3 times with 1.0 mm beads.

[0023] Preferably, the parameters for high-temperature baking and curing in the tunnel oven in step (4) are: the first temperature zone is set to 90℃, the second temperature zone is set to 110℃, the third temperature zone is set to 130℃, the fourth temperature zone is set to 150℃, the fifth temperature zone is set to 160℃, and the baking time is 80-120s.

[0024] This invention provides a black light-shielding covering film and its preparation method, which has the following advantages compared with the prior art:

[0025] The light-shielding film of this invention adopts an environmentally friendly epoxy system. It mainly uses two epoxy resins, DCPD epoxy resin and NPES-901 epoxy resin, compounded in a certain proportion and combined with nitrile rubber to form the main system, ensuring the basic mechanical properties of the material. At the same time, it combines graded aluminum hydroxide and zeolite modified with titanate coupling agent as reinforcing fillers to further improve the mechanical properties of the material and enhance its resistance to thermo-oxidative aging. This prevents the material from aging prematurely due to heat dissipation during use of electronic products, thus affecting its service life. It can meet the high reliability and long lifespan requirements of modern electronic products. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of the black light-shielding covering film prepared in Example 2 of the present invention;

[0027] Figure 2 This is a photograph of the black epoxy adhesive obtained during the preparation process of Experimental Group 1 in this embodiment of the invention.

[0028] Figure 3 These are actual images of the black light-shielding covering films obtained in experimental groups 1-7 of this invention.

[0029] Figure 1 1. PI film; 2. Black epoxy adhesive layer; 3. Release film. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with 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 skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] Example 1:

[0032] Configuration of basic materials:

[0033] 1. The nitrile rubber is NANCAR® 1072CG nitrile rubber produced by Nandi Chemical Industry Co., Ltd.

[0034] 2. Composite epoxy resin:

[0035] Composite epoxy resin 1 is obtained by mixing DCPD epoxy resin and NPES-901 epoxy resin in a mass ratio of 2.5:1;

[0036] Composite epoxy resin 2: It is obtained by mixing DCPD epoxy resin and NPES-901 epoxy resin in a mass ratio of 4:1;

[0037] Composite epoxy resin 3: It is obtained by mixing DCPD epoxy resin and NPES-901 epoxy resin in a mass ratio of 1:1;

[0038] 3. Reinforcing filler:

[0039] 3.1 Reinforcing filler 1:

[0040] (1) Mix aluminum hydroxide with a particle size of 1-10 nm, aluminum hydroxide with a particle size of 0.2-0.5 μm and aluminum hydroxide with a particle size of 5-15 μm in a mass ratio of 1:5:2 until uniform, and then sort the aluminum hydroxide by particle size for later use.

[0041] (2) Dissolve HY-311W titanate coupling agent, which accounts for 4% of the total mass of graded aluminum hydroxide, in an ethanol solution to prepare a coupling agent solution for later use;

[0042] (3) Pour the graded aluminum hydroxide into the coupling agent solution, stir continuously for 2 hours in an oil bath at 80°C, then centrifuge, and vacuum dry the precipitate to obtain modified aluminum hydroxide for later use.

[0043] (4) After mixing modified aluminum hydroxide and zeolite at a mass ratio of 2:1, grind and mix them evenly to obtain reinforcing filler 1.

[0044] 3.2, Reinforcing Filler 2:

[0045] (1) Dissolve 4% of the total mass of aluminum hydroxide titanate coupling agent HY-311W in an ethanol solution to prepare a coupling agent solution for later use;

[0046] (2) Pour aluminum hydroxide (particle size 1-10 nm) into the coupling agent solution, stir continuously for 2 h in an oil bath at 80 °C, then centrifuge, and vacuum dry the precipitate to obtain modified aluminum hydroxide for later use.

[0047] (3) After mixing modified aluminum hydroxide and zeolite at a mass ratio of 2:1, grind and mix them evenly to obtain reinforcing filler 2.

[0048] 3.3, Reinforcing Filler 3:

[0049] (1) Dissolve 4% of the total mass of aluminum hydroxide titanate coupling agent HY-311W in an ethanol solution to prepare a coupling agent solution for later use;

[0050] (2) Pour aluminum hydroxide (particle size: 0.2-0.5μm) into the coupling agent solution, stir continuously for 2 hours in an oil bath at 80℃, then centrifuge, and vacuum dry the precipitate to obtain modified aluminum hydroxide for later use;

[0051] (3) After mixing modified aluminum hydroxide and zeolite at a mass ratio of 2:1, grind and mix them evenly to obtain reinforcing filler 3.

[0052] 3.4, Reinforcing Filler 4:

[0053] (1) Dissolve 4% of the total mass of aluminum hydroxide titanate coupling agent HY-311W in an ethanol solution to prepare a coupling agent solution for later use;

[0054] (2) Pour aluminum hydroxide (particle size: 5-15μm) into the coupling agent solution, stir continuously for 2 hours in an oil bath at 80℃, then centrifuge, and vacuum dry the precipitate to obtain modified aluminum hydroxide for later use.

[0055] (3) After mixing modified aluminum hydroxide and zeolite at a mass ratio of 2:1, grind and mix them evenly to obtain reinforcing filler 4.

[0056] 3.5, Reinforcing filler 5:

[0057] (1) Mix aluminum hydroxide with a particle size of 1-10 nm, aluminum hydroxide with a particle size of 0.2-0.5 μm and aluminum hydroxide with a particle size of 5-15 μm in a mass ratio of 1:5:2 until uniform, and then sort the aluminum hydroxide by particle size for later use.

[0058] (2) Mix graded aluminum hydroxide and zeolite at a mass ratio of 2:1 and grind them evenly to obtain reinforcing filler 5.

[0059] 4. The PI film is a black polyimide film with a thickness of 25µm;

[0060] 5. The release film was purchased from Zhongshan Depu Adhesive Products Co., Ltd., model number JAPEW122-1, and the relevant parameters are: basis weight: 122±5g / m³. 2 Thickness: 135±10μm.

[0061] Example 2:

[0062] Using the raw materials described in the above embodiments, a black light-blocking covering film was prepared:

[0063] (1) Prepare materials according to the following parts by weight: 23 parts of nitrile rubber, 35 parts of composite epoxy resin, 14 parts of reinforcing filler, 15 parts of carbon black, 7 parts of zinc borate, 2.5 parts of 4,4'-diaminodiphenyl sulfone, 0.3 parts of dicyandiamide, and 0.6 parts of antioxidant B215;

[0064] (2) Mix nitrile rubber and butanone at a mass ratio of 1:4 to dissolve and prepare a rubber liquid for later use;

[0065] (3) Take 1 / 2 of the rubber liquid prepared in step (2) above, the reinforcing filler, and zinc borate and add it to methyl ethyl ketone (the amount of methyl ethyl ketone is 1 / 2 of the total volume of the rubber liquid). Stir at 500 r / min for 3 hours, then place it in a sand mill, set the inner cavity of the mill to 1.0 mm beads, grind it 3 times, and obtain the mother liquor for later use.

[0066] (4) Mix the mother liquor, the remaining rubber liquid, carbon black, composite epoxy resin, 4,4'-diaminodiphenyl sulfone, dicyandiamide and antioxidant B215 evenly to make black epoxy glue for later use.

[0067] (5) Apply black epoxy adhesive to the surface of the PI film (coating thickness is 25um), and bake and cure it in a tunnel oven at high temperature (the parameters are set as follows: the first temperature zone is set to 90℃, the second temperature zone is set to 110℃, the third temperature zone is set to 130℃, the fourth temperature zone is set to 150℃, the fifth temperature zone is set to 160℃, and the baking time is 90s) to form a black epoxy adhesive layer. Then, a release film is applied on top of the black epoxy adhesive layer, and after a pressing process, the film is rolled up to obtain a black light-blocking cover film.

[0068] Following the above preparation method, different black light-shielding coating films were prepared by selecting different composite epoxy resins and reinforcing fillers, as shown in Table 1 below:

[0069] Table 1

[0070]

[0071] And the finished products of each group of light-blocking covering films are as follows Figure 3 The differences are minimal to the naked eye, and all exhibit good light-blocking effects.

[0072] Detection:

[0073] 1. Test the mechanical properties of the black light-shielding covering films prepared in each experimental group in Example 2 above:

[0074] The mechanical properties of the black light-shielding cover film in each group were tested using an SMD carrier tape tensile tester (Shenzhen Kexing Precision Instruments Co., Ltd.) according to the operating instructions. The specific results are shown in Table 2 below:

[0075] Table 2

[0076]

[0077] 2. Artificial thermo-oxidative aging tests were conducted on each group of black shading films. The temperature was controlled at 90℃, the oxygen concentration at 95%, and the humidity at 50%. The mechanical properties of each group of black shading films were tested after 24h, 72h, and 168h of treatment. The specific results are shown in Tables 3, 4, and 5 below:

[0078] Table 3 Mechanical properties of each group after 24 hours of artificial thermo-oxidative aging treatment.

[0079]

[0080] Table 4 Mechanical properties of each group after 72 hours of artificial thermo-oxidative aging treatment.

[0081]

[0082] Table 5 Mechanical properties of each group after 168 hours of artificial thermo-oxidative aging treatment.

[0083]

[0084] The loss rates of tensile strength and elongation at break of each group of materials after 168 hours of artificial aging were calculated, and the specific results are shown in Table 6 below:

[0085] Table 6

[0086]

[0087] The above tests show that the black light-shielding cover film in experimental group 4 has the best mechanical properties and aging resistance. Experimental groups 1 and 2, which adjusted the ratio of DCPD epoxy resin and NPES-901 epoxy resin in the composite epoxy resin, have relatively high initial mechanical properties, but poor subsequent aging resistance. Experimental group 3 uses unmodified graded aluminum hydroxide compounded with zeolite, which has high initial mechanical properties, but poor subsequent anti-aging effect. In addition, experimental group 5 uses nano-sized aluminum hydroxide as filler, resulting in poor initial mechanical properties and aging resistance. This may be due to the reduced interfacial interaction, uneven dispersion, and poor mixing uniformity with other raw materials caused by nanoparticles. Experimental group 6 uses coarser aluminum hydroxide as filler, which also results in weaker initial mechanical properties and poor overall aging resistance.

[0088] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A black light-blocking covering film, characterized in that, The black light-shielding covering film includes a PI film and a release film, and a black epoxy adhesive layer coated between the PI film and the release film. The black epoxy adhesive layer is made of the following raw materials in parts by weight: 20-25 parts nitrile rubber, 32-38 parts composite epoxy resin, 12-16 parts reinforcing filler, 12-17 parts carbon black, 6-8 parts flame retardant, 2-3 parts curing agent, 0.2-0.4 parts catalyst, and 0.5-0.8 parts antioxidant. The composite epoxy resin is obtained by mixing DCPD epoxy resin and NPES-901 epoxy resin in a mass ratio of 2.5:

1. The specific preparation method of the reinforcing filler includes the following steps: S1-1. Mix aluminum hydroxide with a particle size of 1-10 nm, aluminum hydroxide with a particle size of 0.2-0.5 μm, and aluminum hydroxide with a particle size of 5-15 μm in a mass ratio of 1:5:2 until homogeneous, and then sort the aluminum hydroxide by particle size for later use. S1-2. Dissolve 3%-5% of the total mass of graded aluminum hydroxide in an ethanol solution to prepare a coupling agent solution for later use. S1-3. Pour the graded aluminum hydroxide into the coupling agent solution, stir continuously for 2 hours in an oil bath at 80°C, then centrifuge, and vacuum dry the precipitate to obtain modified aluminum hydroxide for later use. S1-4. Mix modified aluminum hydroxide and zeolite at a mass ratio of 1-3:1 and grind them evenly to obtain the reinforcing filler.

2. The black light-blocking covering film according to claim 1, characterized in that: The flame retardant is at least one of zinc borate or barium metaborate.

3. The black light-blocking covering film according to claim 1, characterized in that: The curing agent is at least one of 4,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenylmethane, and 3,3'-diethyl-4,4'-diaminodiphenylmethane.

4. The black light-blocking covering film according to claim 1, characterized in that: The catalyst is dicyandiamide.

5. The black light-blocking covering film according to claim 1, characterized in that: The antioxidant is at least one of antioxidant B215, antioxidant 1076, and antioxidant 1010.

6. A method for preparing a black light-shielding covering film as described in any one of claims 1-5, characterized in that: The preparation method includes the following steps: (1) Mix nitrile rubber and butanone at a mass ratio of 1:4 and dissolve them to prepare a rubber liquid; (2) Take 1 / 2 of the rubber liquid prepared in step (1) above, add it together with the reinforcing filler and flame retardant into methyl ethyl ketone and stir for 2-4 hours, then grind it to obtain the mother liquor for later use; (3) Mix the mother liquor, the remaining rubber liquid, carbon black, composite epoxy resin, curing agent, catalyst and antioxidant evenly to make black epoxy glue for later use. (4) Apply black epoxy adhesive to the surface of PI film, bake and cure it at high temperature in a tunnel oven, then apply release film on top of black epoxy adhesive, and roll it up after pressing to obtain black light-blocking cover film.

7. The preparation method according to claim 6, characterized in that: In step (2), the stirring speed is 400-700 r / min, and the grinding process is to place the mixture in a sand mill and grind it 2-3 times with 1.0 mm beads.

8. The preparation method according to claim 6, characterized in that: In step (4), the parameters for high-temperature baking and curing in the tunnel oven are set as follows: the first temperature zone is set to 90℃, the second temperature zone is set to 110℃, the third temperature zone is set to 130℃, the fourth temperature zone is set to 150℃, the fifth temperature zone is set to 160℃, and the baking time is 80-120s.

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