Mini LED display module packaging film and preparation method and application thereof

Abstract

The invention relates to a Mini LED display module packaging film as well as a preparation method and application thereof. A glue solution composition of the Mini LED display module packaging film comprises the following components in parts by weight: 1-7 parts of acrylic acid type modified epoxy resin; 10 to 30 parts of multifunctional UV curing resin; 30-60 parts of epoxy resin; 2-10 parts of a toughening agent; 20-50 parts of a curing agent; 0.1 to 2 parts of a curing accelerator; and 0.05 to 0.5 part of a photoinitiator. The Mini LED display module packaging film provided by the invention has excellent environmental reliability and solvent resistance, the packaging process is simple and convenient, and the requirements of Mini LED direct display screen packaging on packaging efficiency, yield and reliability can be met.

Description

Technical Field

[0001] The present invention relates to the field of packaging technology, and in particular to a Mini LED display module packaging film and a preparation method and application thereof. Background Art

[0002] Mini LED direct display screen uses Mini LED chips directly as display pixels and as the basic unit of image display. It has the advantages of high brightness, wide color gamut, high contrast, high speed response, low power consumption and long life, and has become one of the hot spots in the development of display technology in recent years.

[0003] Compared with the traditional SMD packaging method, the existing Mini LED direct display chip packaging process and the COB packaging method of multi-chip packaging on the PCB board are more in line with the market demand for "thin film, miniaturization, and array". The packaging method mainly selects the packaging process based on the packaging material. The traditional process selection is to use two-component epoxy glue, epoxy plastic packaging material and other materials for molding packaging. At present, based on the direct display panel with smaller and smaller display pixel pitch (P≤0.9mm), the packaging form of the film material prepared by epoxy material is used. The film pressing packaging form has both the repairability of multi-chip large-area sealing and film attachment, which is more conducive to improving production efficiency and product yield and is receiving widespread attention.

[0004] The traditional Mini LED packaging technology is the molding method. For example, the prior art discloses a COB packaging glue and its preparation method. During packaging, it is necessary to first mix the two-component epoxy glue with an appropriate amount of light diffusion powder in proportion and perform vacuum degassing treatment, and then inject it into the molding device to package the direct display panel. After molding, it is transferred to the oven for post-curing to finally obtain the Mini LED direct display screen. This process has a long molding cycle, low efficiency, and high molding consumables cost; it has high requirements on the molding accuracy and size of the equipment, and it is difficult to repair the chip after the product is molded, thereby reducing the product yield. As the size of the Mini LED direct display screen continues to increase, the yield of this process will continue to decline.

[0005] The current packaging films are classified according to the materials and are mainly divided into epoxy films, acrylate films and epoxy-acrylate films.

[0006] In the prior art, liquid epoxy glue is used to prefabricate the packaging film material, and then the epoxy packaging film is used to package the Mini LED direct display screen by rolling / molding. The packaging process using the packaging film is simple, which greatly improves the efficiency and yield of the direct display Mini LED screen packaging. However, the curing method of the epoxy film is single, the degree of pre-curing is difficult to control, the process is unstable, the yield of subsequent packaging is low, and warping and other phenomena are prone to occur. In addition, the epoxy packaging film needs to be stored at low temperature before use, and the storage conditions are harsh and the shelf life is short.

[0007] Epoxy-acrylate film is generally a heat-light curing film. It can be divided into two categories according to the main resin: a packaging film with a modified resin containing both epoxy groups and acrylic groups as the main resin, and a film with a mixture of multifunctional epoxy resin and acrylic resin as the main resin. The modified resin packaging film generally has a large elastic modulus and poor filling of the chip spacing during the subsequent packaging process; while the packaging prepared by mixing multifunctional epoxy resin and acrylic acid, although the degree of curing is relatively more controllable, the Mini LED panel has poor resistance to cold and heat shock after film packaging, and the packaging layer is prone to cracking and fragmentation.

[0008] In response to the above problems, the packaging film has a low yield rate, a complex packaging process, and poor packaging reliability such as cracking and warping in harsh environments, which still need to be urgently solved. Summary of the invention

[0009] In order to solve the above technical problems, the present invention provides a Mini LED display module packaging film and a preparation method and application thereof, which solves the technical problems of the existing Mini LED packaging technology such as complex process, low production yield, and poor reliability.

[0010] To achieve this object, the present invention adopts the following technical solutions:

[0011] In a first aspect, the present invention provides a Mini LED display module encapsulation film glue composition, wherein the Mini LED display module encapsulation film glue composition comprises the following components in parts by weight:

[0012] 1-7 parts of acrylic modified epoxy resin;

[0013]

[0014] The present invention realizes a dual-curing system by adding a multifunctional UV curing resin and a multifunctional epoxy resin to the adhesive composition. Under light irradiation, the double bonds undergo free radical polymerization, a cross-linking reaction occurs, and the encapsulation film is cured. Subsequently, the encapsulation film is attached to the surface of the direct display Mini LED by rolling or the like, and the multifunctional epoxy resin component is heated to cure to complete the encapsulation. Due to the different curing excitation modes of the multifunctional UV curing resin and the multifunctional epoxy resin, the curing degree of the encapsulation film is controllable and adjustable.

[0015] Furthermore, the fully cured encapsulation film has poor weather resistance when only the interpenetrating network cross-linked structure is formed by the multifunctional UV curing resin and the multifunctional epoxy resin, and will show fragmentation and cracking after the hot and cold shock test. This is due to the difference in thermal expansion coefficients between the multifunctional UV curing resin and the multifunctional epoxy resin and the slippage between the UV curing network and the epoxy curing network. In order to solve the above problems, the present invention connects the multifunctional epoxy resin network and the UV curing network by adding an acrylic modified multifunctional epoxy resin containing both epoxy groups and double bonds, while increasing the cross-linking density of the system, improving the strength of the film, reducing the thermal expansion coefficient of the film as a whole, and improving the TG point of the cured film, thereby avoiding fragmentation and cracking of the film, thereby improving the yield of the film packaging and achieving the effect of improving reliability.

[0016] In addition, compared with only using acrylate-modified epoxy resin as the main resin of the packaging film, the present invention controls the usage of multifunctional UV-curable resin to 10-30 parts and acrylic modified epoxy resin to 1-7 parts, and obtains a semi-cured packaging film through UV curing between the multifunctional UV-curable resin and the acrylic modified epoxy resin. The subsequent packaging and bonding are followed by thermal curing to complete the packaging process, which can better control the elastic modulus of the semi-cured packaging film, thereby affecting the filling property in the subsequent bonding process and meeting the requirements of Mini LED packaging with small chip spacing. However, when only using acrylate-modified epoxy resin as the packaging film, the elastic modulus is too large, and the spacing between chips cannot be filled during the bonding process, bubbles are easily generated, and the bonding effect is poor.

[0017] In the present invention, in the encapsulation film glue composition, the weight of the acrylic modified epoxy resin can be 1 part, 1.5 parts, 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, 4.5 parts, 5 parts, 5.5 parts, 6 parts, 6.5 parts or 7 parts, as well as specific values ​​between the above points. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific points included in the range. In the present invention, if the weight of the acrylic modified epoxy resin is less than 1 part by weight, the composition has poor solvent resistance, a sticky surface, cracking at the edge after a low temperature test, and cracking of the adhesive layer and dead lights in a hot and cold shock test. If the weight is higher than 7 parts by weight, the adhesion of the encapsulation film deteriorates and the elastic modulus increases, which leads to a significant decrease in the filling rate, bubbles after encapsulation, and delamination after hot and cold shocks.

[0018] In the present invention, in the packaging film glue composition, the weight proportion of the multifunctional UV curable resin can be 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts, 16 parts, 17 parts, 18 parts, 19 parts, 20 parts, 21 parts, 22 parts, 23 parts, 24 parts, 25 parts, 26 parts, 27 parts, 28 parts, 29 parts or 30 parts, as well as specific points between the above points. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific points included in the range.

[0019] In the present invention, in the packaging film glue composition, the weight proportion of the epoxy resin may be 30 parts, 32 parts, 34 parts, 36 parts, 38 parts, 40 parts, 42 parts, 44 parts, 46 parts, 48 ​​parts, 50 parts, 52 parts, 54 parts, 56 parts, 58 parts or 60 parts, as well as specific values ​​between the above-mentioned points. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific points included in the range.

[0020] In the present invention, in the encapsulation film adhesive composition, the weight proportion of the toughening agent can be 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts or 10 parts, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0021] In the present invention, in the encapsulation film glue composition, the weight proportion of the curing agent may be 20 parts, 22 parts, 24 parts, 26 parts, 28 parts, 30 parts, 32 parts, 34 parts, 36 parts, 38 parts, 40 parts, 42 parts, 44 parts, 46 parts, 48 ​​parts or 50 parts, as well as specific values ​​between the above points. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific points included in the range.

[0022] In the present invention, in the encapsulation film adhesive composition, the weight portion of the curing accelerator can be 0.1 part, 0.2 part, 0.3 part, 0.4 part, 0.5 part, 0.6 part, 0.7 part, 0.8 part, 0.9 part, 1 part, 1.1 part, 1.2 parts, 1.3 parts, 1.4 parts, 1.5 parts, 1.6 parts, 1.7 parts, 1.8 parts, 1.9 parts or 2 parts, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the said range.

[0023] In the present invention, in the encapsulation film glue composition, the weight portion of the photoinitiator can be 0.05 part, 0.1 part, 0.15 part, 0.2 part, 0.25 part, 0.3 part, 0.35 part, 0.4 part, 0.45 part or 0.5 part and specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the said range.

[0024] Preferably, the acrylic modified epoxy resin is obtained by capping one end of a macromolecular epoxy resin with an acrylic compound.

[0025] Preferably, the viscosity of the acrylic modified epoxy resin at 25° C. is 60-160 Pa·s, for example, 60 Pa·s, 70 Pa·s, 80 Pa·s, 90 Pa·s, 100 Pa·s, 110 Pa·s, 120 Pa·s, 130 Pa·s, 140 Pa·s, 150 Pa·s or 160 Pa·s, etc.

[0026] Preferably, the acid value of the acrylic modified epoxy resin is less than 0.03 mg / g, such as 0.005 mg / g, 0.01 mg / g, 0.015 mg / g, 0.02 mg / g or 0.025 mg / g, etc.; the epoxy value is 0.2-0.3 mol / 100g, such as 0.2 mol / 100g, 0.21 mol / 100g, 0.22 mol / 100g, 0.23 mol / 100g, 0.24 mol / 100g, 0.25 mol / 100g, 0.26 mol / 100g, 0.27 mol / 100g, 0.28 mol / 100g, 0.29 mol / 100g or 0.3 mol / 100g, etc.

[0027] Preferably, the preparation method of the acrylic modified epoxy resin comprises the following steps:

[0028] S1, mixing macromolecular epoxy resin with inhibitor;

[0029] S2, adding a mixture of acrylic compound and catalyst to the mixture of step S1, and reacting to obtain the acrylic modified epoxy resin.

[0030] Preferably, the acrylic compound includes methacrylic acid and / or acrylic acid.

[0031] Preferably, the functionality of the macromolecular epoxy resin is 2, and the macromolecular epoxy resin includes any one of bisphenol A epoxy resin, hydrogenated bisphenol A epoxy resin, bisphenol F epoxy resin, hydrogenated bisphenol F epoxy resin, alicyclic epoxy resin, and aromatic-alicyclic epoxy resin, or a combination of at least two thereof.

[0032] Further preferably, the macromolecular epoxy resin includes any one of hydrogenated bisphenol A epoxy resin, hydrogenated bisphenol F epoxy resin or alicyclic epoxy resin, or a combination of at least two thereof.

[0033] In the present invention, the use of the hydrogenated bisphenol A epoxy resin, hydrogenated bisphenol F epoxy resin, and alicyclic epoxy resin can better ensure the yellowing resistance of the adhesive film after curing, improve weather resistance, and avoid affecting the LED direct display effect.

[0034] Preferably, the molar ratio of the acrylic compound to the macromolecular epoxy resin is (1-1.1):1, for example, 1:1, 1.01:1, 1.02:1, 1.03:1, 1.04:1, 1.05:1, 1.06:1, 1.07:1, 1.08:1, 1.09:1 or 1.1:1, etc.

[0035] Preferably, the inhibitor in step S1 includes any one of hydroquinone, p-hydroxyanisole or 1,4-naphthoquinone, or a combination of at least two thereof.

[0036] In the present invention, the inhibitor is used to inhibit the self-polymerization of acrylic compounds, thereby preventing the self-polymerization from causing the reaction failure of the modified epoxy resin.

[0037] Preferably, the mass of the inhibitor in step S1 is 0.002-0.02wt.% of the mass of the macromolecular epoxy resin, for example, 0.002wt.%, 0.004wt.%, 0.006wt.%, 0.008wt.%, 0.010wt.%, 0.012wt.%, 0.014wt.%, 0.016wt.%, 0.018wt.% or 0.02wt.%, etc.

[0038] Preferably, the mixing in step S1 is carried out at 70-80°C, for example, 70°C, 71°C, 72°C, 73°C, 74°C, 75°C, 76°C, 77°C, 78°C, 79°C or 80°C, etc.; and for 10-30 min, for example, 10 min, 12 min, 14 min, 16 min, 18 min, 20 min, 22 min, 24 min, 26 min, 28 min, or 30 min, etc.

[0039] Preferably, the catalyst in step S2 includes any one of N,N-dimethylformamide, 1,4-lutidine or N,N-dimethylcyclohexylamine, or a combination of at least two thereof.

[0040] Preferably, the mass of the catalyst in step S2 is 0.1-2wt.%, of the macromolecular epoxy resin in step S1, for example, 0.1wt.%, 0.2wt.%, 0.3wt.%, 0.4wt.%, 0.5wt.%, 0.6wt.%, 0.7wt.%, 0.8wt.%, 0.9wt.%, 1wt.%, 1.1wt.%, 1.2wt.%, 1.3wt.%, 1.4wt.%, 1.5wt.%, 1.6wt.%, 1.7wt.%, 1.8wt.%, 1.9wt.% or 2wt.%, etc.

[0041] Preferably, the reaction in step S2 is carried out at 70-80°C, for example, 70°C, 71°C, 72°C, 73°C, 74°C, 75°C, 76°C, 77°C, 78°C, 79°C or 80°C, etc., after mixing for 30-40min, for example, 30min, 31min, 32min, 33min, 34min, 35min, 36min, 37min, 38min, 39min or 40min, etc., and then the temperature is raised to 80°C for reaction for 30-50min, for example, 30min, 32min, 34min, 36min, 38min, 40min, 42min, 44min, 46min, 48min or 50min n, etc., until the acid value is less than 0.03 mg / g, for example, 0.005 mg / g, 0.01 mg / g, 0.015 mg / g, 0.02 mg / g or 0.025 mg / g; the epoxide value is 0.2-0.3 mol / 100 g, for example, 0.2 mol / 100 g, 0.21 mol / 100 g, 0.22 mol / 100 g, 0.23 mol / 100 g, 0.24 mol / 100 g, 0.25 mol / 100 g, 0.26 mol / 100 g, 0.27 mol / 100 g, 0.28 mol / 100 g, 0.29 mol / 100 g or 0.3 mol / 100 g, etc.

[0042] The acrylic modified epoxy resin used in the present invention has a functionality of 1 during UV curing; the multifunctional UV curing resin has a functionality of 2 during UV curing; and the multifunctional epoxy resin only participates in thermal curing reaction.

[0043] Preferably, the multifunctional UV curable resin includes pure acrylate resin and modified acrylate resin.

[0044] Preferably, the mass ratio of the pure acrylic resin to the modified acrylic resin is 5:(0.5-3), such as 5:0.5, 5:1, 5:1.5, 5:2, 5:2.5 or 5:3.

[0045] Preferably, the hardness of the pure acrylic resin is less than 65A, for example, 65A, 60A, 55A, 50A, 45A, 40A, 35A, 30A, 25A, 20A, 15A, 10A, 5A, etc.; the elongation at break is greater than 300%, for example, 350%, 400%, 450%, 500%, 550%, 600%, 650%, 700%, 750% or 800%, etc.

[0046] Preferably, the viscosity of the pure acrylate resin at 25° C. is 6000-25000 cps, for example, 6000 cps, 7000 cps, 8000 cps, 9000 cps, 10000 cps, 11000 cps, 12000 cps, 13000 cps, 14000 cps, 15000 cps, 16000 cps, 17000 cps, 18000 cps, 19000 cps, 20000 cps, 21000 cps, 20000 cps, 22000 cps, 23000 cps, 24000 cps or 25000 cps.

[0047] Preferably, the functionality of the pure acrylate resin is 2.

[0048] Preferably, the hardness of the modified acrylic resin is >62D, for example, 62D, 63D, 64D, 65D, 70D, 72D, 75D, 80D, 82D, 85D, etc.; the elongation at break is <15%, for example, 12%, 10%, 8%, 6%, 4% or 2%, etc.

[0049] Preferably, the viscosity of the modified acrylate resin at 25° C. is 9000-100000 cps, for example, 9000 cps, 9100 cps, 9200 cps, 9300 cps, 9400 cps, 9500 cps, 9600 cps, 9700 cps, 9800 cps, 9900 cps or 10000 cps.

[0050] Preferably, the functionality of the modified acrylate resin is 2.

[0051] Preferably, the modified acrylate resin includes polyurethane acrylate and / or epoxy acrylate.

[0052] In the present invention, the combination of the pure acrylate resin and the modified acrylate resin can adjust the flexibility of the film, better make up for the step difference between the Mini LED chip and the substrate, and better fill the gap between the display pixel pitches, thereby meeting the requirements of the current packaging film production line.

[0053] Preferably, the epoxy resin includes any one or a combination of at least two of bisphenol A epoxy resin, halogenated bisphenol A epoxy resin, bisphenol S epoxy resin, bisphenol F epoxy resin, alicyclic epoxy resin, aliphatic epoxy resin, fatty-alicyclic epoxy resin, aromatic-alicyclic epoxy resin, glycerol epoxy resin, ethylene glycol epoxy resin, phenolic epoxy resin, amino epoxy resin, unsaturated epoxy resin, acrylic epoxy resin, tripolyphosphazene epoxy resin, dicyclopentadiene epoxy resin, polybutadiene epoxy resin, organic titanium epoxy resin, organic silicon epoxy resin or fluorine-containing epoxy resin.

[0054] Preferably, the epoxy value of the epoxy resin is 0.44-0.85 mol / 100g, for example, 0.44 mol / 100g, 0.45 mol / 100g, 0.46 mol / 100g, 0.47 mol / 100g, 0.48 mol / 100g, 0.49 mol / 100g, 0.5 mol / 100g, 0.51 mol / 100g, 0.52 mol / 100g, 0.53 mol / 100g, 0.54 mol / 100g, 0.55 mol / 100g, 0. The content of the present invention is 0.5mol / 100g, 0.57mol / 100g, 0.58mol / 100g, 0.59mol / 100g, 0.6mol / 100g, 0.65mol / 100g, 0.70mol / 100g, 0.78mol / 100g, 0.79mol / 100g, 0.8mol / 100g, 0.81mol / 100g, 0.82mol / 100g, 0.83mol / 100g, 0.84mol / 100g or 0.85mol / 100g, etc.

[0055] Preferably, the toughening agent includes any one of acrylic rubber, core-shell structured styrene-butadiene rubber, nitrile rubber-modified epoxy resin, polyurethane-modified epoxy resin or polyol, or a combination of at least two thereof.

[0056] Preferably, the curing agent includes any one of polyetheramine, methylhexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, hexahydrophthalic anhydride or tetrahydrophthalic anhydride curing agent, or a combination of at least two thereof.

[0057] Preferably, the curing accelerator includes any one of nonylphenol, methanol, tetramethylammonium bromide, tetrabutylammonium bromide or triphenylphosphine, or a combination of at least two thereof.

[0058] Preferably, the light diffusion powder includes any one of silicone microspheres, polystyrene microspheres, polymethyl methacrylate, and silicon dioxide, or a combination of at least two of them.

[0059] Preferably, the Mini LED display module packaging film glue composition also includes 0.1-20 parts (for example, 0.1 parts, 0.5 parts, 1 parts, 2 parts, 4 parts, 6 parts, 8 parts, 10 parts, 12 parts, 14 parts, 16 parts, 18 parts or 20 parts) of light diffusion powder and / or 0.5-1 parts (for example, 0.5 parts, 0.6 parts, 0.7 parts, 0.8 parts, 0.9 parts or 1 parts) of coupling agent by weight.

[0060] Preferably, the coupling agent includes any one of methyltriethoxysilane, 3-glycidyloxypropyltrimethoxysilane, γ-aminopropyltriethoxysilane or γ-(meth)acryloxypropyltrimethoxysilane, or a combination of at least two thereof.

[0061] Preferably, the photoinitiator includes any one of hydroxycyclohexane phenone, trimethylbenzoyl-diphenylphosphine oxide, 2,4,6-trimethylbenzoyl-di(p-tolyl)phosphine oxide, phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide or 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone, or a combination of at least two thereof.

[0062] Preferably, the Mini LED display module packaging film glue composition also includes 0.05-15 parts of black colorant by weight, for example, 0.05 parts, 1 parts, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, 11 parts, 12 parts, 13 parts, 14 parts or 15 parts.

[0063] In the invention, a MiniLED display module packaging film glue composition is prepared, and a MiniLED display module packaging film using the MiniLED display module packaging film glue composition is prepared. On this basis, a black colorant can be added to make an integrated color packaging film to reduce the background color filling of the MiniLED module.

[0064] In a second aspect, the present invention provides a Mini LED display module packaging film, which includes a film adhesive layer, a light release film and a heavy release film, wherein the film adhesive layer is located between the light release film and the heavy release film, and the film adhesive layer is obtained by curing the above-mentioned Mini LED display module packaging film glue composition.

[0065] Preferably, the thickness of the membrane adhesive layer is 50-500 μm, for example, 50 μm, 100 μm, 150 μm, 200 μm, 250 μm, 300 μm, 350 μm, 400 μm, 450 μm or 500 μm.

[0066] Preferably, the material of the light release film and the heavy release film is independently selected from any one of a silicone release film and a non-silicone release film.

[0067] Preferably, the non-silicone release film comprises a fluorine release film.

[0068] Preferably, the difference in release force between the heavy release film and the light release film is 5-40 gf / in, for example, 5 gf / in, 10 gf / in, 15 gf / in, 20 gf / in, 25 gf / in, 30 gf / in, 35 gf / in or 40 gf / in, and more preferably 5-30 gf / in.

[0069] Preferably, the thickness of the light release film is 25-125μm, for example, 25μm, 35μm, 45μm, 55μm, 65μm, 75μm, 85μm, 95μm, 105μm, 115μm or 125μm; the thickness of the heavy release film is 75-188μm, for example, 75μm, 85μm, 95μm, 105μm, 115μm, 125μm, 135μm, 145μm, 155μm, 165μm, 175μm, 185μm or 188μm, etc.

[0070] In a third aspect, the present invention provides an application of the Mini LED display module packaging film glue composition or the Mini LED display module packaging film in LED direct display module packaging.

[0071] Preferably, the packaging method is roll lamination or hot pressing lamination.

[0072] Roller lamination method:

[0073] Cut the Mini LED display module packaging film into the required size and remove the first release film, and tightly fit the Mini LED display module packaging film and the Mini LED direct display module by rolling after the first release film is torn off.

[0074] Furthermore, the operation method of roller lamination is as follows: placing the adhesive film on the roller lamination device, aligning the Mini LED display module packaging film with the Mini LED direct display module panel, starting the device, and applying a pressure of more than 0.6kg / cm 2 , rolling speed <2m / min. Preferably, the applied pressure is 0.8-1.5kg / cm 2 , for example 0.8kg / cm 2 , 0.9kg / cm 2 , 1.0kg / cm 2 , 1.1kg / cm 2 , 1.2kg / cm 2 , 1.3kg / cm 2 , 1.4kg / cm 2 or 1.5kg / cm 2 etc.; the rolling speed is 0.5-1m / min, for example, 0.5m / min, 0.6m / min, 0.7m / min, 0.8m / min, 0.9m / min or 1m / min, etc.

[0075] Bake the roll-pressed packaged Mini LED direct display module in an oven at 130-140°C, such as 130°C, 131°C, 132°C, 133°C, 140°C, 135°C, 136°C, 137°C, 138°C, 139°C or 140°C for 1-2h, such as 1.1h, 1.2h, 1.3h, 1.4h, 1.5h, 1.6h, 1.7h, 1.8h, 1.9h or 2h, and then transfer Move to an oven at 70-80°C, such as 70°C, 71°C, 72°C, 73°C, 74°C, 75°C, 76°C, 77°C, 78°C, 79°C or 80°C, and continue post-curing for 1-2 hours, such as 1h, 1.1h, 1.2h, 1.3h, 1.4h, 1.5h, 1.6h, 1.7h, 1.8h, 1.9h or 2h, and then tear off the second release film to complete the packaging.

[0076] Hot pressing bonding method:

[0077] Cut the Mini LED display module packaging film into the required size and remove the first release film, and place the Mini LED display module packaging film after removing the first release film on the top of the Mini LED direct display module chip.

[0078] The Mini LED display module packaging film and the Mini LED direct display module placed together are placed in a pressing machine with a vacuum cavity, and the display module and the Mini LED display module packaging film are heated while vacuuming, and the direct display module and the Mini LED display module packaging film are heated at the same time; after the vacuum is maintained for 1-2 minutes, for example, 1min, 1.1min, 1.2min, 1.3min, 1.4min, 1.5min, 1.6min, 1.7min, 1.8min, 1.9min or 2min, pressurize the two together, and continue the vacuum pressurization for 2-3min, for example, 2min, 2.1min, 2.2min, 2.3min, 2.4min, 2.5min, 2.6min, 2.7min, 2.8min, 2.9min or 3min, the bonding operation can be completed.

[0079] Further, the vacuum degree is preferably 0.1 MPa, the pressure is preferably 0.1-1.5 MPa, for example, 0.1 MPa, 0.2 MPa, 0.3 MPa, 0.4 MPa, 0.5 MPa, 0.6 MPa, 0.7 MPa, 0.8 MPa, 0.9 MPa, 1 MPa, 1.1 MPa, 1.2 MPa, 1.3 MPa, 1.4 MPa or 1.5 MPa, etc., and the platform heating temperature is preferably 25-90°C, for example, 25°C, 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C or 90°C, etc.

[0080] Furthermore, the pressure is preferably 0.3-0.6Mpa, for example 0.3Mpa, 0.35Mpa, 0.4Mpa, 0.45Mpa, 0.5Mpa, 0.55Mpa or 0.6Mpa, etc.; the temperature is preferably 25-90°C, for example 25°C, 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C or 90°C, etc.

[0081] Bake the pressed and packaged Mini LED direct display module in an oven at 130-140°C, such as 130°C, 131°C, 132°C, 133°C, 140°C, 135°C, 136°C, 137°C, 138°C, 139°C or 140°C for 1-2h, such as 1h, 1.1h, 1.2h, 1.3h, 1.4h, 1.5h, 1.6h, 1.7h, 1.8h, 1.9h or 2h, and then Transfer to an oven at 70-80°C, such as 70°C, 71°C, 72°C, 73°C, 74°C, 75°C, 76°C, 77°C, 78°C, 79°C or 80°C, and continue post-curing for 1-2h, such as 1h, 1.1h, 1.2h, 1.3h, 1.4h, 1.5h, 1.6h, 1.7h, 1.8h, 1.9h or 2h, etc., and then tear off the second release film to complete the packaging.

[0082] In a fourth aspect, the present invention provides a method for preparing the above-mentioned Mini LED display module packaging film, comprising the following steps:

[0083] A Mini LED display module packaging film glue composition as described in the first aspect is coated on one side of the first release film, and then UV-cured, and then a second release film is attached to the side of the Mini LED display module packaging film glue composition away from the first release film, and the film is cut into strips and rolled up to obtain the Mini LED display module packaging film.

[0084] Preferably, the method of coating the Mini LED display module packaging film glue composition on one side of the first release film includes any one of slit coating, comma blade coating, anilox coating, micro-concave coating, transfer coating or spraying.

[0085] Preferably, the UV curing light source includes any one or a combination of a low-pressure mercury lamp, an ultraviolet UV lamp tube, and an ultraviolet LED lamp.

[0086] Preferably, the illumination of the UV curing is 30-1000 mW / cm 2 , for example 30mW / cm 2 , 100mW / cm 2 , 200mW / cm 2 、300mW / cm 2 , 400mW / cm 2 , 500mW / cm 2 、600mW / cm 2 、700mW / cm 2 、800mW / cm 2 、900mW / cm 2 or 1000mW / cm 2etc.; curing energy 2500-5000mJ / cm 2 , for example 2500mJ / cm 2 、3000mJ / cm 2 、3500mJ / cm 2 、4000mJ / cm 2 、4500mJ / cm 2 、5000mJ / cm 2 wait.

[0087] Compared with the prior art, the present invention has at least the following beneficial effects:

[0088] 1. A Mini LED display module packaging film provided by the present invention has excellent mechanical properties, adhesion and film-forming properties, and after bonding and curing, provides a Mini LED direct display module packaging film with excellent reliability.

[0089] 2. Compared with the traditional Molding liquid encapsulation glue, the encapsulation process of the present invention is simpler, the production efficiency and yield are higher, and the pressing thickness between batches is more uniform.

[0090] 3. The Mini LED display module packaging film provided by the present invention has good solvent resistance.

[0091] 4. The Mini LED display module packaging film provided by the present invention has excellent anti-delamination and anti-fragmentation effects in harsh environments, which can protect the Mini LED chip from intrusion and avoid the occurrence of dead light phenomenon. BRIEF DESCRIPTION OF THE DRAWINGS

[0092] Figure 1 This is a schematic diagram of the structure of the display module packaging film in the present invention:

[0093] 1. Light release film, 2. Heavy release film, 3. Mini LED display module packaging film. DETAILED DESCRIPTION

[0094] To facilitate understanding of the present invention, the present invention lists embodiments and application examples as follows. Those skilled in the art should understand that the embodiments and application examples are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0095] The sources of raw materials used in the following examples and comparative examples are as follows:

[0096] 1. Multifunctional UV curable resin pure acrylate resin HS-1060, from Huisheng Technology;

[0097] 2. Multifunctional UV curable resin polyurethane acrylate CN1964NS, from Sartomer;

[0098] 3. Multifunctional UV curable resin epoxy acrylic resin 6215-100, from Changxing Materials;

[0099] 4. Epoxy resin liquid bisphenol A epoxy resin E-42, from Green Union Chemical Technology;

[0100] 5. Epoxy resin liquid bisphenol A type epoxy resin E-44, from Yucai Chemical;

[0101] 6. Epoxy resin Bisphenol F type epoxy resin NPEF-170, from Nan Ya Plastics Industry;

[0102] 7. Epoxy resin alicyclic epoxy resin 2021P, from Daicel, Japan;

[0103] 8. Epoxy resin aliphatic epoxy resin DER732, from Dow Chemical;

[0104] 9. Toughening agent polyester polyol Priplast3190, from Croda;

[0105] 10. Toughening agent polyester diol EP-HS2272, from Evonik, Germany;

[0106] 11. Toughening agent nitrile rubber modified epoxy resin MY33-3, from Mingyuan Chemical;

[0107] 12. Toughening agent core-shell structure styrene-butadiene rubber MX-553, from KANEKA (Japan);

[0108] 13. Toughening agent polyurethane modified epoxy resin EPU-133L, from Kain Chemical;

[0109] 14. Light diffusion powder silicone microsphere KMP-590, from Shin-Etsu, Japan;

[0110] 15. Curing agent polyetheramine D230, from BASF;

[0111] 16. Curing agent polyetheramine D400, from BASF;

[0112] 17. Curing agent polyetheramine D2000, from BASF;

[0113] 18. Photoinitiator hydroxycyclohexyl phenyl ketone 184, from Shanghe Chemical;

[0114] 19. Photoinitiator trimethylbenzoyl-diphenylphosphine oxide TPO, from Shanghe Chemical.

[0115] The preparation methods of the Mini LED display module encapsulation film glue compositions in the following embodiments and comparative examples are as follows:

[0116] Step 1. Add multifunctional UV curable resin, acrylic modified epoxy resin, multifunctional epoxy resin, toughening agent and photoinitiator into a dispersion kettle according to weight parts, and disperse them for 1.5 hours at room temperature using a high-speed disperser to obtain a mixed composition A;

[0117] In step 1, light diffusion powder and coupling agent may be added in parts by weight;

[0118] Step 2. Grind and disperse the mixed composition A using a ceramic three-roll mill for 2-3 times to obtain a dispersed mixed composition A, and cool it to room temperature for standby use;

[0119] Step 3. Add the dispersed mixed composition A, curing agent and curing accelerator into the reactor, mix and stir for 30 minutes to obtain a mixed composition B;

[0120] Step 4. Place the product obtained in step S3 in a vacuum degassing box, and evacuate for 60 minutes at a vacuum degree of -0.1 MPa to obtain a Mini LED display module packaging film glue composition.

[0121] Example 1

[0122]

[0123] The acrylic modified epoxy resin is a methacrylic acid modified epoxy resin, and the preparation method comprises the following steps:

[0124] S1: Add 45 g of hydrogenated bisphenol A resin (ADEKA resin EP-4080E, 0.1 mol) and 0.004 g of hydroquinone (inhibitor) into a reaction vessel equipped with a condenser, a dropping funnel, a thermometer and a stirrer, heat to 75°C, and stir evenly for 30 min;

[0125] S2: Mix methacrylic acid (8.61 g, 0.10 mol) and N,N-dimethylformamide (0.23 g, 0.5 wt.% of hydrogenated bisphenol A resin) in an equal molar ratio and dissolve them in a dropping funnel, and add them dropwise to the reaction vessel within 1 h;

[0126] After the addition is completed, the reaction is maintained at 75°C with stirring for 30 minutes, then the temperature is raised and maintained at 80°C, and the stirring reaction is continued for 30 minutes. During this period, the reaction progress is monitored by sampling and testing the resin acid value and epoxy value until the acid value is <0.03 mg / g and the epoxy value is ≈0.2 mol / 100 g, which means the reaction is completed. The mixture is cooled to obtain methacrylic acid modified epoxy resin.

[0127] The multifunctional UV curable resin is pure acrylate resin HS-1060: polyurethane acrylate CN1964NS: epoxy acrylate resin 6215-100 in a mass ratio of 15:2:1;

[0128] The epoxy resin is bisphenol A epoxy resin E42: bisphenol F resin NPEF-170: alicyclic epoxy resin 2021P in a mass ratio of 5:5:7;

[0129] The toughening agent is polyester polyol Priplast3190;

[0130] The curing agent is methyl hexahydrophthalic anhydride;

[0131] The curing accelerator is tetrabutylammonium bromide;

[0132] The light diffusion powder is organic silicon microsphere KMP-590;

[0133] The coupling agent is γ-(meth)acryloxypropyltrimethoxysilane;

[0134] The photoinitiator is hydroxycyclohexyl phenyl ketone 184:trimethylbenzoyl-diphenylphosphine oxide TPO in a mass ratio of 2:1.

[0135] Example 2

[0136]

[0137]

[0138] The acrylic modified epoxy resin is a methacrylic acid modified epoxy resin, and the preparation method comprises the following steps:

[0139] S1: Add 47 g of bisphenol F epoxy resin (Nan Ya NPEF-170, 0.1 mol) and 0.004 g of p-hydroxyanisole (inhibitor) into a reaction vessel equipped with a condenser, a dropping funnel, a thermometer and a stirrer, heat to 80°C, and stir evenly for 10 min;

[0140] S2: Mix methacrylic acid (8.61 g, 0.1 mol) and a catalyst 1,4-dimethylpyridine (0.24 g, 1 wt.% of bisphenol F epoxy resin) in an equal molar ratio, place in a dropping funnel, and drop into the reaction vessel within 1 h;

[0141] After the addition is completed, the reaction is maintained at 80°C with stirring for 40 minutes, then the temperature is raised and maintained at 80°C, and the stirring reaction is continued for 50 minutes. During this period, the reaction progress is monitored by sampling and testing the resin acid value and epoxy value until the acid value is <0.03 mg / g and the epoxy value is ≈0.3 mol / 100 g, which means the reaction is completed. The mixture is cooled to obtain methacrylic acid modified epoxy resin.

[0142] The multifunctional UV curable resin is pure acrylate resin HS-1060: epoxy acrylate resin 6215-100 in a mass ratio of 15:2;

[0143] The epoxy resin is bisphenol A epoxy resin E44: bisphenol F resin NPEF-170: aliphatic epoxy resin DER732 in a mass ratio of 5:5:7;

[0144] The toughening agent is a core-shell structure of styrene-butadiene rubber MY33-3:nitrile rubber modified epoxy resin in a mass ratio of 5:1;

[0145] The curing agent is polyetheramine D400:polyetheramine D2000 in a mass ratio of 5:1;

[0146] The curing accelerator is nonylphenol;

[0147] The light diffusion powder is silicone microspheres;

[0148] The coupling agent is methyltriethoxysilane;

[0149] The photoinitiator is trimethylbenzoyl-diphenylphosphine oxide TPO.

[0150] Example 3

[0151]

[0152] The acrylic modified epoxy resin is a methacrylic acid modified epoxy resin, and the preparation method comprises the following steps:

[0153] S1: Add 43 g of alicyclic epoxy resin (Dacel 2021P, 0.1 mol) and 0.004 g of 1,4-naphthoquinone (inhibitor) into a reaction vessel equipped with a condenser, a dropping funnel, a thermometer and a stirrer, heat to 70°C, and stir evenly for 20 min;

[0154] S2: An equal molar ratio of methacrylic acid (8.61 g, 0.1 mol) and a dissolved catalyst N,N-dimethylcyclohexylamine (0.22 g, 1.5 wt.% of the alicyclic epoxy resin) were mixed and placed in a dropping funnel and added dropwise to the reaction vessel within 1 h;

[0155] After the addition is completed, the reaction is maintained at 70°C with stirring for 35 minutes, then the temperature is raised and maintained at 80°C, and the stirring reaction is continued for 40 minutes. During this period, the reaction progress is monitored by sampling and testing the resin acid value and epoxy value until the acid value is <0.03 mg / g and the epoxy value is ≈0.25 mol / 100 g, which means the reaction is completed. The mixture is cooled to obtain methacrylic acid modified epoxy resin.

[0156] The multifunctional UV curable resin is pure acrylate resin HS-1060: polyurethane acrylate CN1964NS in a mass ratio of 15:2;

[0157] The epoxy resin is bisphenol A epoxy resin E44: bisphenol F resin NPEF-170: alicyclic epoxy resin 2021P in a mass ratio of 5:5:6;

[0158] The toughening agent is polyester polyol Priplast3190: polyester diol EP-HS2272 in a mass ratio of 2:1;

[0159] The curing agent is methyl hexahydrophthalic anhydride;

[0160] The curing accelerator is triphenylphosphine;

[0161] The light diffusion powder is organic silicon microsphere KMP-590;

[0162] The coupling agent is 3-glycidyloxypropyltrimethoxysilane;

[0163] The photoinitiator is 2-benzyl-2-dimethylamino-1-(4-morpholinephenyl)butanone.

[0164] Example 4

[0165]

[0166] The acrylic acid-modified epoxy resin is an acrylic acid-modified epoxy resin, and the preparation method comprises the following steps:

[0167] S1: Add 45 g of hydrogenated bisphenol A resin (ADEKA resin EP-4080E, 0.1 mol) and 0.004 g of hydroquinone (inhibitor) into a reaction vessel equipped with a condenser, a dropping funnel, a thermometer and a stirrer, heat to 75°C, and stir evenly for 30 min;

[0168] S2: acrylic acid (7.21 g, 0.10 mol) and N,N-dimethylformamide (0.23 g, 0.5 wt.% of hydrogenated bisphenol A resin) in equal molar ratio were mixed and dissolved in a dropping funnel and added dropwise to the reaction vessel within 1 h;

[0169] After the addition is completed, the reaction is maintained at 75°C with stirring for 30 minutes, then the temperature is raised and maintained at 80°C, and the stirring reaction is continued. During this period, the reaction progress is monitored by sampling and testing the resin acid value and epoxy value until the acid value is <0.03 mg / g and the epoxy value is ≈0.2 mol / 100 g, which means the reaction is completed. The mixture is cooled to obtain an acrylic modified epoxy resin.

[0170] The multifunctional UV curable resin is pure acrylate resin HS-1060: polyurethane acrylate CN1964NS: epoxy acrylate resin 6215-100 in a mass ratio of 14:1:2;

[0171] The epoxy resin is bisphenol A epoxy resin E42: bisphenol F resin NPEF-170: alicyclic epoxy resin 2021P: aliphatic epoxy resin in a mass ratio of 5:5:7:1;

[0172] The toughening agent is polyester polyol Priplast3190;

[0173] The curing agent is methyl hexahydrophthalic anhydride;

[0174] The curing accelerator is tetrabutylammonium bromide;

[0175] The light diffusion powder is silicone microspheres;

[0176] The coupling agent is γ-aminopropyltriethoxysilane;

[0177] The photoinitiator is 2,4,6-trimethylbenzoyl-di(p-tolyl)phosphine oxide.

[0178] Example 5

[0179]

[0180]

[0181] The acrylic modified resin is the same as in Example 4;

[0182] The multifunctional UV curable resin is pure acrylate resin HS-1060: polyurethane acrylate CN1964NS in a mass ratio of 15:2.5;

[0183] The epoxy resin is bisphenol A epoxy resin E44: bisphenol F resin NPEF-170: alicyclic epoxy resin 2021P in a mass ratio of 5:5:6;

[0184] The toughening agent is nitrile rubber modified epoxy resin;

[0185] The curing agent is polyetheramine D230:polyetheramine D400:polyetheramine D2000 in a mass ratio of 1:4:1;

[0186] The curing accelerator is nonylphenol:methanol in a mass ratio of 3:1

[0187] The light diffusion powder is organic silicon microsphere KMP-590;

[0188] The coupling agent is γ-(meth)acryloxypropyltrimethoxysilane;

[0189] The photoinitiator is hydroxycyclohexyl phenyl ketone 184.

[0190] Comparative Example 1

[0191] The difference from Example 1 is that the amount of methacrylic acid modified epoxy resin used is 0.8 parts.

[0192] Comparative Example 2

[0193] The difference from Example 1 is that the amount of methacrylic acid modified epoxy resin used is 8 parts.

[0194] Comparative Example 3

[0195] The difference from Example 1 is that the methacrylic acid-modified epoxy resin is replaced by an equal amount of epoxy acrylate (Changxing Material 6215-100) not containing epoxy groups.

[0196] Comparative Example 4

[0197] The difference from Example 1 is that the amount of the multifunctional UV curable resin is 35 parts.

[0198] Comparative Example 5

[0199] The difference from Example 1 is that the amount of the multifunctional UV curable resin is 8 parts.

[0200] Application Example 1

[0201] The Mini LED display module encapsulation film glue composition obtained in Example 1 was added to the glue tank of the coating equipment and coated between the light release film 1 (PET, thickness 100 μm) and the heavy release film 2 (PET, thickness 100 μm) with a coating thickness of 150 μm. After being cured in a Philips UV lamp light box (UV lamp power: 60 W, light energy 4000 mJ / cm 2 ), and roll up to obtain the MiniLED display module packaging film.

[0202] Application Example 2-5

[0203] The difference from Application Example 1 is that the Mini LED display module packaging film glue composition is replaced by the Mini LED display module packaging film glue composition obtained in Preparation Example 2-5.

[0204] Comparative Application Examples 1-5

[0205] The difference from Application Example 1 is that the Mini LED display module packaging film glue composition is replaced by the Mini LED display module packaging film glue composition obtained in Comparative Preparation Examples 1-5.

[0206] Performance Testing

[0207] The performance of the packaging films of the corresponding use cases and comparative application cases was tested. The test method is as follows:

[0208] (I) Testing of basic properties of film

[0209] The Mini LED display module packaging films of the corresponding use cases 1-5 and comparative application examples 1-5 were tested. The test results are shown in Table 1. The test method is as follows:

[0210] Film tearing force test: GB / T 25256-2010 Test method for 180° peeling force and residual adhesion rate of optical functional film release film is used to test the 180° film tearing force of light and heavy release films.

[0211] Elastic modulus: Use a rheometer to test the storage modulus data of the film's elastic modulus. Cut the film to a suitable size based on the size of the rheometer test fixture to ensure that the film is flat and covers the test area. Start the rheometer and begin testing under the set temperature, frequency, and strain conditions. Take the average storage modulus at 25°C based on the storage modulus change curve.

[0212] (II) Hardness and adhesion effects of adhesive film after bonding to Mini LED thermal curing package

[0213] Thermally cure the adhesive film prepared by the Mini LED of Application Examples 1-5 or Comparative Application Examples 1-5 ( Curing at 130℃ for 2h ) After that, the test was carried out. The test results are shown in Table 1. The test method is as follows:

[0214] Hardness: Tested in accordance with GB / T 531.1-2008 Test method for indentation hardness of vulcanized rubber or thermoplastic rubber Part 1: Shore durometer method (Shore hardness)

[0215] Adhesion: GB / T 1727-92 General preparation method for paint film is used for 100-grid adhesion test.

[0216] (III) Film bonding and lighting effects

[0217] After tearing off the light release film of the adhesive film prepared for the Mini LED of Application Examples 1-5 or Comparative Application Examples 1-5, the adhesive film layer was bonded to the Mini LED light board with a bonding pressure of 0.7 MPa and a bonding temperature of 80°C, and then cured at 130°C for 2h. After complete curing, the heavy release film was removed to obtain a Mini LED module, and the following tests were performed.

[0218] Solvent resistance: Dip a piece of pure cotton cloth in anhydrous ethanol (concentration ≥ 95%) and wrap it on a 500g weight (the area of ​​the test head after wrapping with cotton cloth is about 1cm 2 ), wipe back and forth on the sample surface for 50 cycles at a speed of 40-60 times / min and a stroke of about 20mm.

[0219] Result judgment: After the test, the cured film is qualified if there is no discoloration or whitening, no heavy scratches, and the surface is not sticky.

[0220] Filling rate test method: According to the chip height X of the LED light board, use a packaging film with a gradient thickness difference to fit and fill by rolling or hot pressing. After fitting, place it at 90℃ for 3-5 minutes. If there is no debonding or bubbling between the film and the chip, it means the filling is good. The minimum thickness that can achieve good filling is Y, and the filling rate is: X / Y*100%.

[0221] Warp test method: After the Mini LED module cutting process edge is completely cured, lay the display surface flat on an absolutely flat plane and measure the distance between the center of the light board and the plane.

[0222] Environmental resistance test: Place the Mini LED module after film encapsulation in the corresponding environmental test conditions for testing, and take it out for observation after the test structure. The environmental test will be judged based on the appearance of cracks, debonding, delamination of the adhesive layer, uneven color stripes when the module is lit, and dead lights.

[0223] Table 1 Performance of OCA optical adhesive with integrated black effect

[0224]

[0225] Table 2 Mini LED direct display module bonding and curing test

[0226]

[0227]

[0228] Note: The test in this table uses Mini LED chips with a chip pitch of 0.9mm and a chip height of 85μm.

[0229] The comprehensive performance of application examples 1-3 of the present invention is excellent. The packaging film is adapted to light and heavy tearing forces, and there will be no reverse release phenomenon. It has good adhesion and appropriate elastic modulus, which is conducive to filling the chip spacing in the subsequent packaging process. The chip is well filled after bonding and packaging, and the filling rate is >80%. After complete curing, the warpage is low, the solvent resistance is good, and there are no abnormal phenomena after low temperature, high temperature, high temperature and high humidity, and cold and hot shock tests. Application examples 1-3 control the multifunctional UV curing resin at 20-30 parts to make the packaging film state, and the storage modulus in the elastic modulus is 15-20Kpa, which meets the filling requirements of different chip spacings (0.3-1.5mm), thereby improving the subsequent weather resistance.

[0230] All performances in Application Example 4 meet the standards, and have good fitting and reliability performance for existing mainstream Mini LED light boards. However, the multifunctional UV resin component is relatively large and has a relatively large modulus. For light boards with unconventional lamp bead heights (chips greater than 175μm high), the adhesive film has a certain impact on the filling of the light board. The multifunctional UV curing resin is only aliphatic polyurethane acrylate, and all performances meet the standards. However, its light and heavy tearing forces are relatively large, which has a certain impact on the existing packaging film automation process and efficiency.

[0231] The multifunctional UV curing resin component in Application Example 5 is relatively small, and various performances are up to standard, but its light and heavy film tearing forces are relatively large, which has a certain impact on the existing packaging film automation process and efficiency.

[0232] In comparative application example 1, too little methacrylic acid-modified epoxy resin was added, resulting in poor solvent resistance, a sticky surface, cracking at the edges after a low-temperature test, and cracking of the adhesive layer and dead light in a hot and cold shock test.

[0233] In comparative application example 2, the amount of methacrylic acid modified epoxy resin added is too much, and the adhesion of the packaging film becomes poor; the elastic modulus increases, which leads to a significant decrease in the filling rate, bubbles appear after packaging, and delamination occurs after hot and cold shocks.

[0234] In comparative application example 3, epoxy acrylate resin containing only acrylic groups but no epoxy groups is used to replace the methacrylic acid-modified epoxy resin in Example 1. The solvent resistance is reduced, while the filling rate of the adhesive film is significantly reduced. Edge cracking occurs in the low-temperature test, and the adhesive layer breaks and the lamp dies during the heat and cold shock.

[0235] In contrast, too much multifunctional UV curing resin was added in Application Example 4, the elastic modulus of the encapsulation film increased, the filling rate was significantly reduced, and the corresponding cross-linking ratio of the methacrylate modified epoxy resin and the multifunctional UV curing resin component was relatively reduced, resulting in a decrease in solvent resistance and a deterioration in weather resistance.

[0236] In comparison, less multifunctional UV curable resin is added in Application Example 5, and the resin is in a viscous flow state after UV curing, and cannot form a packaging film.

[0237] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A Mini LED display module encapsulation film glue composition, characterized in that: The Mini LED display module encapsulation film glue composition comprises the following components in parts by weight:

2. The Mini LED display module encapsulation film glue composition according to claim 1, characterized in that: The acrylic modified epoxy resin is obtained by capping one end of a macromolecular epoxy resin with an acrylic compound; Preferably, the viscosity of the acrylic modified epoxy resin at 25° C. is 60-160 Pa·s; Preferably, the acid value of the acrylic modified epoxy resin is less than 0.03 mg / g, and the epoxy value is 0.2-0.3 mol / 100g.

3. The Mini LED display module encapsulation film glue composition according to claim 1 or 2, characterized in that: The preparation method of the acrylic modified epoxy resin comprises the following steps: S1, mixing macromolecular epoxy resin with inhibitor; S2, adding a mixture of an acrylic compound and a catalyst to the mixture of step S1, and reacting to obtain the acrylic modified epoxy resin; Preferably, the acrylic compound includes methacrylic acid and / or acrylic acid; Preferably, the functionality of the macromolecular epoxy resin is 2, including any one or a combination of at least two of bisphenol A epoxy resin, hydrogenated bisphenol A epoxy resin, bisphenol F epoxy resin, hydrogenated bisphenol F epoxy resin, alicyclic epoxy resin or aromatic-alicyclic epoxy resin; Further preferably, the macromolecular epoxy resin includes any one or a combination of at least two of hydrogenated bisphenol A epoxy resin, hydrogenated bisphenol F epoxy resin or alicyclic epoxy resin; Preferably, the molar ratio of the acrylic compound to the macromolecular epoxy resin is (1-1.1):1; Preferably, the inhibitor in step S1 comprises any one of hydroquinone, p-hydroxyanisole or 1,4-naphthoquinone, or a combination of at least two thereof; Preferably, the mass of the inhibitor in step S1 is 0.002-0.02wt.% of the mass of the macromolecular epoxy resin; Preferably, the mixing in step S1 is performed at 70-80° C. for 10-30 min; Preferably, the catalyst in step S2 comprises any one of N,N-dimethylformamide, 1,4-lutidine or N,N-dimethylcyclohexylamine, or a combination of at least two thereof; Preferably, the mass of the catalyst in step S2 is 0.1-2 wt.% of the macromolecular epoxy resin in step S1; Preferably, in step S2, the reaction is mixed at 70-80° C. for 30-40 min, then heated to 80° C. for 30-50 min, until the acid value is less than 0.03 mg / g and the epoxy value is 0.2-0.3 mol / 100 g.

4. The Mini LED display module encapsulation film glue composition according to any one of claims 1 to 3, characterized in that: The multifunctional UV curable resin includes pure acrylate resin and modified acrylate resin; Preferably, the mass ratio of the pure acrylic resin to the modified acrylic resin is 5:(0.5-3); Preferably, the hardness of the pure acrylic resin is less than 65A, and the elongation at break is greater than 300%; Preferably, the viscosity of the pure acrylate resin at 25° C. is 6000-25000 cps; Preferably, the functionality of the pure acrylate resin is 2; Preferably, the hardness of the modified acrylic resin is greater than 62D, and the elongation at break is less than 15%; Preferably, the viscosity of the modified acrylate resin at 25° C. is 9000-100000 cps; Preferably, the functionality of the modified acrylate resin is 2; Preferably, the modified acrylate resin includes polyurethane acrylate and / or epoxy acrylate.

5. The Mini LED display module encapsulation film glue composition according to any one of claims 1 to 4, characterized in that: The multifunctional epoxy resin includes any one or a combination of at least two of bisphenol A epoxy resin, halogenated bisphenol A epoxy resin, bisphenol S epoxy resin, bisphenol F epoxy resin, alicyclic epoxy resin, aliphatic epoxy resin, aliphatic-alicyclic epoxy resin, aromatic-alicyclic epoxy resin, glycerol epoxy resin, phenolic epoxy resin, amino epoxy resin, unsaturated epoxy resin, acrylic epoxy resin, tripolyphosphazene epoxy resin, dicyclopentadiene epoxy resin, polybutadiene epoxy resin, organic titanium epoxy resin, organic silicon epoxy resin or fluorine-containing epoxy resin; Preferably, the epoxy value of the multifunctional epoxy resin is 0.44-0.85 mol / 100g.

6. The Mini LED display module encapsulation film glue composition according to any one of claims 1 to 5, characterized in that: The toughening agent includes any one or a combination of at least two of acrylic rubber, core-shell structured styrene-butadiene rubber, nitrile rubber-modified epoxy resin, polyurethane-modified epoxy resin or polyol; Preferably, the curing agent comprises any one of polyetheramine, methyl hexahydrophthalic anhydride, methyl tetrahydrophthalic anhydride, hexahydrophthalic anhydride or tetrahydrophthalic anhydride curing agent or a combination of at least two thereof; Preferably, the curing accelerator comprises any one or a combination of at least two of nonylphenol, methanol, tetramethylammonium bromide, tetrabutylammonium bromide or triphenylphosphine; Preferably, the light diffusion powder includes any one of silicone microspheres, polystyrene microspheres, polymethyl methacrylate or silicon dioxide, or a combination of at least two of them.

7. The Mini LED display module encapsulation film glue composition according to any one of claims 1 to 6, characterized in that: The Mini LED display module encapsulation film glue composition further comprises 0.1-20 parts of light diffusion powder and / or 0.5-1 parts of coupling agent in parts by weight; Preferably, the coupling agent includes any one of methyltriethoxysilane, 3-glycidyloxypropyltrimethoxysilane, γ-aminopropyltriethoxysilane or γ-(meth)acryloxypropyltrimethoxysilane, or a combination of at least two thereof; Preferably, the photoinitiator comprises any one of hydroxycyclohexane phenone, trimethylbenzoyl-diphenylphosphine oxide, 2,4,6-trimethylbenzoyl-di(p-tolyl)phosphine oxide, phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide or 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone or a combination of at least two thereof; Preferably, the Mini LED display module packaging film glue composition further includes 0.05-5 parts by weight of a black colorant.

8. A Mini LED display module packaging film, characterized in that: The Mini LED display module packaging film includes a film adhesive layer, a light release film and a heavy release film, the film adhesive layer is located between the light release film and the heavy release film, and the film adhesive layer is obtained by curing the Mini LED display module packaging film glue composition described in any one of claims 1 to 7.

9. The Mini LED display module packaging film according to claim 8, characterized in that: The thickness of the membrane adhesive layer is 50-500 μm; Preferably, the material of the light release film and the heavy release film is independently selected from any one of a silicone release film and a non-silicone release film; Preferably, the non-silicone release film comprises a fluorine release film; Preferably, the difference in release force between the heavy release film and the light release film is 5-40 gf / in, more preferably 5-30 gf / in; Preferably, the light release film has a thickness of 25-125 μm; and the heavy release film has a thickness of 75-188 μm.

10. Application of the Mini LED display module packaging film glue composition according to any one of claims 1 to 7 or the Mini LED display module packaging film according to claim 8 or 9 in LED direct display module packaging; Preferably, the packaging method is roll lamination or hot pressing lamination.

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