Packaging film glue solution composition, packaging film as well as preparation method and application of packaging film

Abstract

The invention provides a packaging film glue solution composition, a packaging film as well as a preparation method and application of the packaging film. The packaging film glue solution composition is prepared from the following components in parts by weight: 10 to 30 parts of organic silicon modified aliphatic polyurethane acrylate resin, 0.1 to 5 parts of UV (Ultraviolet) reactive diluent, 30 to 60 parts of epoxy resin, 2 to 12 parts of flexibilizer, 20 to 55 parts of curing agent, 0.1 to 2 parts of accelerant, 5 to 20 parts of light diffusion powder, 0.02 to 1.0 part of coupling agent and 0.05 to 0.5 part of photoinitiator, the organic silicon modified aliphatic polyurethane acrylate resin is prepared from the following raw materials: polyester glycol, carbon-terminated hydroxyl polydimethylsiloxane, a diisocyanate compound and hydroxyl acrylate; the molar ratio of the polyester diol to the carbon-terminated hydroxyl polydimethylsiloxane is (15-45): 1; the UV active diluent comprises an epoxy acrylate compound. The packaging film glue solution composition provided by the invention has good film-forming property, and a packaging film prepared from the packaging film glue solution composition is good in environmental reliability and has high filling rate when a Mini LED display module is packaged.

Description

Technical Field

[0001] The invention belongs to the technical field of LED display module packaging, and in particular relates to a packaging film glue composition, a packaging film, and a preparation method and application thereof. Background Art

[0002] Mini LED display screens have become one of the hot spots in the development of display technology in recent years. Mini LED direct display screens use MiniLED chips directly as display pixels and as the basic unit of image display. They have the advantages of high brightness, wide color gamut, high contrast, high-speed response, low power consumption and long life. At present, based on the direct display panel with smaller and smaller display pixel pitch (P≤0.9mm), the form of packaging using film materials made of epoxy materials is receiving widespread attention, because the film pressing packaging form has both multi-chip large-area sealing and film attachment repairability, which is more conducive to improving production efficiency and product yield.

[0003] The traditional Mini LED packaging technology is the molding method. CN110845980A discloses a COB packaging glue and a preparation method thereof. The COB packaging glue includes a first composition and a second composition, and the mass ratio of the first composition and the second composition is between 2:1 and 5:1; the first composition includes: 100 parts of epoxy resin, 110-120 parts of silicon micropowder, 0-10 parts of negative thermal expansion filler, 0-5 parts of diluent, 0-2 parts of light diffuser, 0-2 parts of matte powder, 10-15 parts of toughening agent, 0.3-1 parts of antioxidant, 0.3-1 parts of anti-ultraviolet aging agent, 0.01-0.03 parts of colorant, 0.01-0.05 parts of defoaming agent; the second composition includes: 50-90 parts of curing agent, 6-8 parts of curing accelerator. When encapsulating the COB encapsulation glue provided by this technical solution, it is necessary to first mix the first composition and the second composition in proportion with an appropriate amount of light diffusion powder and perform vacuum degassing treatment, and then inject them into the molding device to encapsulate the direct display panel. After molding, it is transferred to an oven for post-curing to finally obtain a Mini LED direct display screen. The 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 molding is completed, thereby reducing the yield of the product. As the size of the Mini LED direct display screen continues to increase, the yield of this process will continue to decline.

[0004] CN116622320A discloses a Mini LED screen packaging film, a preparation method and a packaging method, wherein the Mini LED screen packaging film comprises a first release film, a second release film and a semi-cured film layer disposed between the first release film and the second release film; the semi-cured film layer is composed of the following components by weight: 100 parts of epoxy resin, 5 to 15 parts of UV resin, 120 to 200 parts of silicon powder, 5 to 15 parts of active diluent, 0.1 to 1 part of solvent-free carbon black slurry, 0 to 5 parts of fumed silica, 80 to 90 parts of anhydride curing agent, 0.1 to 1 part of anhydride curing accelerator and 0.01 to 0.1 part of photoinitiator. This technical solution can improve the efficiency and yield of packaging by pre-forming the glue into a packaging film material, and then using a roller pressing method to encapsulate the packaging film material on the display panel to form a direct display screen, but it is prone to the problem of low filling rate.

[0005] In the prior art, the Mini LED display module is packaged by injecting the glue into the molding device, which has the problems of complex process, low production efficiency and low yield, poor uniformity of lamination thickness between batches; the Mini LED display module is packaged by pre-forming the glue into a film and then laminating it, which has the problems of low lamination filling rate, easy delamination of the high-chip light board, poor process adaptability, etc. In the prior art, the encapsulation film of the epoxy-acrylic system is mostly obtained by constructing an interpenetrating cross-linked network of epoxy curing and acrylic curing, applying the encapsulation glue on the surface of the release film, cross-linking the acrylic system through photocuring, and then after lamination, thermal curing is used to cure the epoxy component to achieve encapsulation. However, its high and low temperature resistance is poor, and the encapsulation glue is prone to cracking after 500h of -40℃ and 120℃ hot and cold shock.

[0006] Therefore, it is necessary to develop a packaging film to solve the problems of low filling rate, high warping degree, and poor environmental reliability in Mini LED display module packaging. Summary of the invention

[0007] In view of the deficiencies of the prior art, the object of the present invention is to provide a packaging film glue composition, a packaging film and a preparation method and application thereof. The packaging film glue composition has good film-forming properties, and the packaging film prepared therefrom has high adhesion, good solvent resistance, and low water vapor permeability, and has a high filling rate, low warpage, and good environmental reliability when encapsulating a Mini LED display module.

[0008] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0009] In a first aspect, the present invention provides an encapsulation film adhesive composition, which comprises the following components in parts by weight: 10 to 30 parts (e.g., 12 parts, 14 parts, 16 parts, 18 parts, 20 parts, 22 parts, 24 parts, 26 parts or 28 parts) of an organosilicon-modified aliphatic polyurethane acrylate resin, 0.1 to 5 parts (e.g., 0.3 parts, 0.5 parts, 1 parts, 1.5 parts, 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts or 4.5 parts) of a UV-active diluent, 30 to 60 parts (e.g., 35 parts, 40 parts, 45 parts, 50 parts or 55 parts) of an epoxy resin, 2 to 12 parts (e.g., 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts or 11 parts) of a toughening agent. ), curing agent 20-55 parts (for example, 25 parts, 30 parts, 35 parts, 40 parts, 45 parts or 50 parts, etc.), accelerator 0.1-2 parts (for example, 0.3 parts, 0.6 parts, 0.9 parts, 1.2 parts, 1.5 parts or 1.8 parts, etc.), light diffusion powder 5-20 parts (for example, 7 parts, 9 parts, 11 parts, 13 parts, 15 parts, 17 parts or 19 parts, etc.), coupling agent 0.02-1.0 parts (0.1 parts, 0.2 parts, 0.3 parts, 0.4 parts, 0.5 parts, 0.6 parts, 0.7 parts, 0.8 parts or 0.9 parts, etc.) and photoinitiator 0.05-0.5 parts (0.1 parts, 0.15 parts, 0.2 parts, 0.25 parts, 0.3 parts, 0.35 parts, 0.4 parts or 0.45 parts, etc.);

[0010] The raw materials for preparing the organosilicon-modified aliphatic polyurethane acrylate resin include polyester diol, terminal carbon hydroxyl polydimethylsiloxane, diisocyanate compound and hydroxy acrylate;

[0011] The molar ratio of the polyester diol to the terminal carbon hydroxyl polydimethylsiloxane is (15-45):1, such as 18:1, 21:1, 24:1, 27:1, 30:1, 33:1, 36:1, 39:1 or 42:1;

[0012] The UV-active diluent includes an epoxy acrylate compound.

[0013] In the present invention, by using epoxy acrylate compounds as UV-active diluents, the epoxy cross-linking network formed by the epoxy resin and the acrylic cross-linking network formed by the silicone-modified aliphatic polyurethane acrylate resin are connected during curing, thereby reducing the problem of cracking caused by the difference between the epoxy cross-linking network and the acrylic cross-linking network, while increasing the cross-linking density of the system and improving the strength of complete curing.

[0014] The present invention can improve the problem of poor filling effect and increased modulus of the encapsulation film formed by curing due to the addition of an epoxy acrylate compound by adding an organosilicon-modified aliphatic polyurethane acrylate resin. Moreover, the polyester segment and the polysiloxane segment in the organosilicon-modified aliphatic polyurethane acrylate resin can effectively improve the filling property of the encapsulation film, and the introduction of the polysiloxane segment can reduce the water absorption rate of the encapsulation film, improve the water vapor barrier and solvent wiping resistance. The encapsulation film glue composition prepared by compounding an organosilicon-modified aliphatic polyurethane acrylate resin, a UV-active diluent, an epoxy resin, a toughening agent, a curing agent, an accelerator, a light diffusion powder, a coupling agent and a photoinitiator has good film-forming properties, and the encapsulation film formed by the composition has high adhesion, good solvent resistance and low water vapor permeability, and can be encapsulated in an LED direct display module by roller lamination or hot pressing lamination, and has a high filling rate, low warping and good environmental reliability.

[0015] Preferably, the molar ratio of the diisocyanate compound to the polyester diol is 1:(0.5-1.0), for example, 1:0.55, 1:0.6, 1:0.65, 1:0.7, 1:0.75, 1:0.8, 1:0.85, 1:0.9 or 1:0.95, etc.

[0016] Preferably, the molar ratio of the hydroxy acrylate to the diisocyanate compound is 1:(0.8-1.2), for example, 1:0.85, 1:0.9, 1:0.95, 1:1, 1:1.05, 1:1.1 or 1:1.15.

[0017] Preferably, the preparation method of the silicone-modified aliphatic polyurethane acrylate resin comprises the following steps:

[0018] (1) A polyester diol, a terminal carbon hydroxyl polydimethylsiloxane and a diisocyanate compound are mixed and subjected to a condensation reaction to obtain an isocyanate-terminated silicone-modified polyurethane prepolymer.

[0019] (2) The isocyanate-terminated silicone-modified polyurethane prepolymer obtained in step (1) is terminated with hydroxy acrylate to obtain the silicone-modified aliphatic polyurethane acrylate resin.

[0020] Preferably, the polyester diol includes any one of polyethylene adipate diol, polyneopentyl adipate diol, polycaprolactone glycol ester diol, polypropylene adipate diol, polybutylene adipate-1,4-diol or polyneopentyl terephthalate diol, or a combination of at least two thereof.

[0021] Preferably, the diisocyanate compound includes any one or a combination of at least two of 4,4'-dicyclohexylmethane diisocyanate, 2,4-trimethylhexane diisocyanate, methylcyclohexylene diisocyanate, dicyclohexylmethylene diisocyanate, toluene diisocyanate, hexamethylene diisocyanate or isophorone diisocyanate.

[0022] Preferably, the hydroxyacrylate includes any one of hydroxyethyl methacrylate, hydroxyethyl acrylate, hydroxypropyl methacrylate, hydroxypropyl acrylate, hydroxybutyl methacrylate or hydroxybutyl acrylate, or a combination of at least two thereof.

[0023] Preferably, the temperature of the condensation reaction in step (1) is 80-85°C (e.g., 81°C, 82°C, 83°C or 84°C, etc.), and the time is 2-7h (e.g., 2.5h, 3h, 3.5h, 4h, 4.5h, 5h, 5.5h, 6h or 6.5h, etc.).

[0024] Preferably, the reaction temperature of the end-capping in step (2) is 60-70°C (for example, 62°C, 64°C, 66°C or 68°C, etc.), and the reaction time is 2-4h (for example, 2.3h, 2.6h, 2.9h, 3.2h, 3.5h or 3.8h, etc.).

[0025] Preferably, the mixing in step (1) further comprises mixing with an antioxidant, a solvent, a chain extender and a catalyst.

[0026] Preferably, the antioxidant includes any one of triphenyl phosphite, diisodecyl phosphite, trinonylphenyl phosphite or bisphenol A phosphite, or a combination of at least two thereof.

[0027] Preferably, the solvent includes any one or a combination of at least two of dimethylformamide (DMF), N,N-dimethylacetamide (DMAC), dimethyl sulfoxide (DMSO), N-methylpyrrolidone (NMP) or tetrahydrofuran (THF).

[0028] Preferably, the chain extender includes any one of ethylene glycol, 1,2-propylene glycol, 1,6-hexanediol or diethylene glycol (DEG), or a combination of at least two thereof.

[0029] Preferably, the catalyst comprises any one of dibutyltin dilaurate, dibutyltin diacetate, dioctyltin diacetate, dibutyltin maleate or stannous octoate, or a combination of at least two thereof.

[0030] Preferably, the mass ratio of the antioxidant to the polyester diol is 0.1:(100-130), for example, 0.1:105, 0.1:110, 0.1:115, 0.1:120 or 0.1:125, etc.

[0031] Preferably, the mass ratio of the solvent to the polyester diol is (1-3):1, for example, 1:1, 1.3:1, 1.6:1, 1.9:1, 2.2:1, 2.5:1 or 2.8:1, etc.

[0032] Preferably, the molar ratio of the chain extender to the polyester diol is 1:(1-3), for example, 1:1.3, 1:1.6, 1:1.9, 1:2.2, 1:2.5 or 1:2.8, etc.

[0033] Preferably, the mass of the catalyst is 0.002% to 0.006% of the mass of the diisocyanate compound, for example, 0.0025%, 0.003%, 0.0035%, 0.004%, 0.0045%, 0.005% or 0.0055%, etc.

[0034] Preferably, the preparation method of the silicone-modified aliphatic polyurethane acrylate resin specifically comprises the following steps:

[0035] (1) The polyester diol, the terminal carbon hydroxyl polydimethylsiloxane, the antioxidant and part of the solvent are heated to 30-50° C. (e.g., 33° C., 36° C., 39° C., 42° C., 45° C. or 48° C., etc.) under nitrogen protection and premixed for 20-40 min (e.g., 23 min, 26 min, 29 min, 32 min, 35 min or 38 min, etc.), part of the diisocyanate compound is added and reacted at 80-85° C. (e.g., 81° C., 82° C., 83° C. or 84° C., etc.) for 2-3 h (e.g., 2.2 h, 2.4 h, 2.6 h or 2.8 h, etc.), the remaining solvent and the mixed solution of the chain extender are added and maintained at 80-85° C. (e.g., 81° C., 83° C. or 84° C., etc.) for 2-3 h (e.g., 2.2 h, 2.4 h, 2.6 h or 2.8 h, etc.), the mixture is added and maintained at 80-85° C. (e.g., 81° C. , 82°C, 83°C or 84°C, etc.) and then react for 30-40min (for example, 31min, 32min, 33min, 34min, 35min, 36min, 37min, 38min or 39min, etc.), add the remaining diisocyanate compound, keep at 80-85°C for reaction for 1-1.5h (for example, 1.1h, 1.2h, 1.3h or 1.4h, etc.), add the catalyst and keep at 80-85°C (for example, 81°C, 82°C, 83°C or 84°C, etc.) and continue to react for 2-2.5h (for example, 2.1h, 2.2h, 2.3h or 2.4h, etc.) to obtain an isocyanate-terminated silicone modified polyurethane prepolymer.

[0036] (2) The isocyanate-terminated silicone-modified polyurethane prepolymer obtained in step (1) is cooled to 60-65° C. (e.g., 62° C., 64° C., 66° C., or 68° C.), hydroxy acrylate is added, and the end-capping reaction is carried out for 2-4 hours (e.g., 2.3 hours, 2.6 hours, 2.9 hours, 3.2 hours, 3.5 hours, or 3.8 hours), thereby obtaining the silicone-modified aliphatic polyurethane acrylate resin.

[0037] Preferably, the end-capping reaction further includes a post-treatment step, and the post-treatment is reduced-pressure rotary evaporation.

[0038] In the present invention, the solvent and small molecular substances are removed by reduced pressure rotary evaporation.

[0039] Preferably, the mass of the part of the solvent is 20% to 60% of the total mass of the solvent, for example, 25%, 30%, 35%, 40%, 45%, 50% or 55%.

[0040] Preferably, the molar amount of the diisocyanate compound in the portion accounts for 65% to 75% of the total molar amount of the diisocyanate compound, for example, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73% or 74%, etc.

[0041] Preferably, the viscosity of the silicone-modified aliphatic polyurethane acrylate resin at 25° C. is 20,000 to 110,000 mPa·s, such as 30,000 mPa·s, 50,000 mPa·s, 70,000 mPa·s or 90,000 mPa·s.

[0042] Preferably, the silicone-modified aliphatic polyurethane acrylate resin has an elongation at break of 400% to 850% (for example, 450%, 500%, 550%, 600%, 650%, 700%, 750% or 800%, etc.), and a hardness of 40 to 80A (for example, 45A, 50A, 55A, 60A, 65A, 70A or 75A, etc.).

[0043] In the present invention, the elongation at break and hardness of the silicone-modified aliphatic polyurethane acrylate resin refer to the results of mixing silicone-modified aliphatic polyurethane acrylate resin, hydroxycyclohexane phenone (photoinitiator 184) and 2,4,6-trimethylbenzoyl-di(p-tolyl)phosphine oxide (photoinitiator TPO) in a mass ratio of 100:0.2:0.2, and testing after UV curing, wherein the sample for the elongation at break test is a film with a thickness of 250 μm.

[0044] Preferably, the weight proportion of the silicone-modified aliphatic polyurethane acrylate resin in the encapsulation film glue composition is 15 to 20 parts, for example, 15.5 parts, 16 parts, 16.5 parts, 17 parts, 17.5 parts, 18 parts, 18.5 parts, 19 parts or 19.5 parts.

[0045] Preferably, the weight proportion of the UV active diluent in the encapsulation film glue composition is 0.3 to 3 parts, for example, 0.6 parts, 0.9 parts, 1.2 parts, 1.5 parts, 1.8 parts, 2.1 parts, 2.4 parts or 2.7 parts.

[0046] Preferably, the epoxy acrylate compound includes glycidyl methacrylate (GMA) and / or glycidyl acrylate.

[0047] Preferably, the UV-active diluent further comprises an acrylate compound free of epoxy groups.

[0048] Preferably, the epoxy-free acrylate compound includes any one of trimethylolpropane triacrylate (TMPTA), pentaerythritol triacrylate (PETIA), ethoxylated trimethylolpropane triacrylate (TMP3EOTA), 1,6-hexanediol diacrylate (HDDA), isooctyl acrylate (EHA), lauryl acrylate (LA) or isobornyl acrylate (IBOA), or a combination of at least two thereof.

[0049] Preferably, the epoxy resin comprises a difunctional epoxy resin and / or a tetrafunctional epoxy resin.

[0050] Preferably, the difunctional 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, fat-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, fluorine-containing epoxy resin or aliphatic epoxy resin.

[0051] Preferably, the aliphatic epoxy resin is Dow epoxy resin DER732.

[0052] Preferably, the toughening agent includes any one of polyester polyol, acrylic rubber, core-shell structure styrene-butadiene rubber, nitrile rubber modified epoxy resin, polyurethane modified epoxy resin or polyether polyol, or a combination of at least two thereof.

[0053] Preferably, the polyester polyol comprises polyester diol.

[0054] Preferably, the polyester polyol includes Croda Priplast 3190.

[0055] Preferably, the curing agent comprises a polyetheramine curing agent and / or an acid anhydride curing agent.

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

[0057] Preferably, the 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 or polymethyl methacrylate microspheres, or a combination of at least two of them.

[0059] 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.

[0060] Preferably, the photoinitiator comprises any one of hydroxycyclohexane phenyl ketone (184), 2,4,6-trimethylbenzoyl-di(p-tolyl)phosphine oxide (TPO), phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide (819) or 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone (369), or a combination of at least two thereof.

[0061] Preferably, the encapsulation film adhesive composition further comprises a black pigment.

[0062] The present invention can prepare a one-piece color packaging film by adding black pigment, thereby reducing the background color filling of the Mini LED module.

[0063] In a second aspect, the present invention provides a method for preparing the encapsulation film glue composition as described in the first aspect, the preparation method comprising the following steps: mixing a silicone-modified aliphatic polyurethane acrylate resin, a UV-active diluent, an epoxy resin, a toughening agent, a curing agent, an accelerator, a light diffusion powder, a coupling agent and a photoinitiator to obtain the encapsulation film glue composition.

[0064] Preferably, the preparation method specifically comprises the following steps:

[0065] (I) Mixing an organosilicon-modified aliphatic polyurethane acrylate resin, a UV-active diluent, an epoxy resin, a toughening agent, a light-diffusing powder, a coupling agent, and a photoinitiator to obtain a premix.

[0066] (II) Grinding and dispersing the premix prepared in step (I), and then mixing it with a curing agent and an accelerator to obtain the encapsulating film glue composition.

[0067] Preferably, step (II) further comprises a vacuuming step after the mixing.

[0068] In a third aspect, the present invention provides a packaging film, comprising a first release film layer, a packaging film adhesive layer and a second release film layer stacked in sequence, wherein the packaging film adhesive layer is made of the packaging film adhesive composition as described in the first aspect.

[0069] Preferably, the thickness of the encapsulation film adhesive layer is 50-500 μm, for example, 100 μm, 150 μm, 200 μm, 250 μm, 300 μm, 350 μm, 400 μm or 450 μm.

[0070] Preferably, the first release film layer and the second release film layer independently include any one of a silicone release film, a non-silicone release film or a fluorine release film, or a combination of at least two of them.

[0071] Preferably, the first release film layer includes a light release film, and the second release film layer includes a heavy release film.

[0072] In the present invention, the release forces of the first release film layer and the second release film layer are compared, and the one with greater release force is a heavy release film, and the one with less release force is a light release film.

[0073] Preferably, the thickness of the light release film is 25 to 125 μm (for example, 30 μm, 50 μm, 70 μm, 90 μm or 110 μm, etc.), and the release force is 1 to 15 gf / in (for example, 2 gf / in, 4 gf / in, 6 gf / in, 8 gf / in, 10 gf / in, 12 gf / in or 14 gf / in, etc.).

[0074] Preferably, the thickness of the heavy release film is 75 to 188 μm (for example, 80 μm, 100 μm, 120 μm, 140 μm, 160 μm or 180 μm, etc.), and the release force is 15 to 40 gf / in (for example, 19 gf / in, 23 gf / in, 27 gf / in, 31 gf / in, 35 gf / in or 39 gf / in, etc.).

[0075] Preferably, the release force difference between the light release film and the heavy release film is 5 to 40 gf / in (eg, 10 gf / in, 20 gf / in, 25 gf / in, 30 gf / in or 35 gf / in, etc.), more preferably 5 to 30 gf / in.

[0076] In a fourth aspect, the present invention provides a method for preparing a packaging film as described in the third aspect, the preparation method comprising the following steps: coating the packaging film adhesive composition as described in the first aspect on one side of the first release film layer, curing with ultraviolet light to form a packaging film adhesive layer, and attaching a second release film layer to the side of the packaging film adhesive layer away from the first release film layer to obtain the packaging film.

[0077] Preferably, the coating comprises any one of slit coating, comma blade coating, screen coating, micro-dimple coating, transfer coating or spray coating, or a combination of at least two thereof.

[0078] Preferably, the light source for UV curing includes any one of a low-pressure mercury lamp, an ultraviolet lamp tube, and an ultraviolet LED lamp, or a combination of at least two of them.

[0079] Preferably, the UV light intensity of the UV curing is 30 to 1000 mW / cm 2 , for example 100mW / cm 2 , 200mW / cm 2 、300mW / cm 2 , 400mW / cm 2 , 500mW / cm 2 、600mW / cm 2 、700mW / cm 2 、800mW / cm 2 or 900mW / cm 2 wait.

[0080] Preferably, the energy of the ultraviolet light used for the ultraviolet curing is 2500-5000 mJ / cm 2 , for example 2800mJ / cm 2 、3100mJ / cm 2 、3400mJ / cm 2 、3700mJ / cm 2 、4000mJ / cm 2 、4300mJ / cm 2 、4600mJ / cm 2 or 4900mJ / cm 2 wait.

[0081] In a fifth aspect, the present invention provides an application of the packaging film as described in the third aspect in the packaging of an LED direct display module.

[0082] Preferably, the LED direct display module is a Mini LED direct display module.

[0083] Preferably, the LED direct display module packaging includes roll-on lamination packaging or hot-press lamination packaging.

[0084] Preferably, the roll-bonding packaging specifically includes the following steps: removing the first release film layer of the packaging film, then rolling and bonding it with the Mini LED direct display module, baking, removing the second release film layer, and completing the roll-bonding packaging.

[0085] Preferably, the roller lamination is performed on a roller pressing device, and the pressure applied by the rubber roller of the roller pressing device is greater than 0.6 kg / cm 2 (e.g. 0.8kg / cm 2 , 1.0kg / cm 2 , 1.2kg / cm 2 , 1.4kg / cm 2 or 1.6kg / cm 2 etc.), more preferably 0.8 to 1.5 kg / cm 2 .

[0086] Preferably, the rolling speed of the rubber roller of the rolling equipment is less than 2 m / min (for example, 0.3 m / min, 0.6 m / min, 0.9 m / min, 1.2 m / min, 1.5 m / min or 1.8 m / min, etc.), and more preferably 0.5-1 m / min.

[0087] Preferably, the baking temperature in the roller-laminated packaging is 130-140°C (for example, 131°C, 132°C, 133°C, 134°C, 135°C, 136°C, 137°C, 138°C or 139°C, etc.), and the time is 0.5-2h (for example, 0.7h, 0.9h, 1.1h, 1.3h, 1.5h, 1.7h or 0.9h, etc.).

[0088] Preferably, the hot pressing and bonding packaging specifically includes the following steps: removing the first release film layer of the packaging film, pasting it on the top of the chip located on the Mini LED direct display module, and then placing it in a pressing machine with a vacuum cavity, bonding and baking under vacuum, heating and pressurization conditions, removing the second release film layer, and completing the roller bonding packaging.

[0089] Preferably, the vacuum degree of the vacuum is -0.09 to -0.1 MPa, for example, -0.091 MPa, -0.092 MPa, -0.093 MPa, -0.094 MPa, -0.095 MPa, -0.096 MPa, -0.097 MPa, -0.098 MPa or -0.099 MPa.

[0090] Preferably, the heating temperature is 25 to 90°C (eg, 30°C, 40°C, 50°C, 60°C, 70°C or 80°C, etc.), more preferably 25 to 35°C.

[0091] Preferably, the pressurized pressure is 0.1 to 1.5 MPa (for example, 0.2 MPa, 0.4 MPa, 0.6 MPa, 0.8 MPa, 1.0 MPa, 1.2 MPa or 1.4 MPa, etc.), and more preferably 0.3 to 0.8 MPa.

[0092] Preferably, the baking temperature in the thermal compression bonding package is 130-140°C (for example, 131°C, 132°C, 133°C, 134°C, 135°C, 136°C, 137°C, 138°C or 139°C, etc.), and the time is 0.5-2h (for example, 0.7h, 0.9h, 1.1h, 1.3h, 1.5h, 1.7h or 0.9h, etc.).

[0093] Preferably, the bonding under vacuum, heating and pressurization conditions specifically includes the following steps: heating the packaging film and the Mini LED direct display module to 25-90°C, evacuating for 1-2 minutes until the vacuum degree is -0.1MPa, and using 0.1-1.5MPa pressure to pressurize the packaging film and the Mini LED direct display module and maintain it for 2-3 minutes.

[0094] Compared with the prior art, the present invention has the following beneficial effects:

[0095] The present invention obtains a packaging film glue composition by compounding silicone-modified aliphatic polyurethane acrylate resin, UV-active diluent, epoxy resin, toughening agent, curing agent, accelerator, light diffusion powder, coupling agent and photoinitiator, which has good film-forming properties. The formed packaging film has high adhesion, good solvent resistance, and low water vapor permeability. It can be used to package LED direct display modules by roller bonding or hot pressing bonding, and has high filling rate, low warping, and good environmental reliability. On the one hand, it effectively solves the problems of complex process, low production efficiency, low yield, and poor uniformity of pressing thickness between batches in the molding method using glue packaging; on the other hand, the packaging film has excellent filling performance for high-chip Mini LED direct display modules, low warping after bonding and curing, good environmental reliability, good aging resistance, easy and convenient use, and can greatly improve production efficiency. The packaging film is rolled and bonded to a Mini LED light board with a chip spacing of only 0.9mm and a height of 85μm. The filling rate can be maintained at >85%, and the warping is below 1.8mm. There are no abnormalities after low temperature, high temperature, high temperature and high humidity, and cold and hot shock tests. In the preferred case, the filling rate can be maintained at >90%, and the warping is below 1mm. BRIEF DESCRIPTION OF THE DRAWINGS

[0096] Figure 1 A schematic diagram of the structure of the packaging film provided in Example 1;

[0097] Among them, 1-first release film layer; 2-encapsulation film adhesive layer; 3-second release film layer. DETAILED DESCRIPTION

[0098] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0099] The sources of some raw materials in the following examples and comparative examples are shown in Table 1.

[0100] Table 1

[0101]

[0102] Preparation Example 1

[0103] This preparation example provides an organosilicon-modified aliphatic polyurethane acrylate resin, specifically an organosilicon-modified aliphatic polyurethane acrylate resin A, and the organosilicon-modified aliphatic polyurethane acrylate resin A is prepared by the following method:

[0104] (1) 200 g of polyethylene adipate diol (number average molecular weight 1000), 30 g of polyneopentyl adipate diol (number average molecular weight 4000), 10 g of terminal carbon hydroxyl polydimethylsiloxane (number average molecular weight 2000), 0.20 g of antioxidant (triphenyl phosphite), and 240 g of solvent (dimethylformamide) were added to a reaction container equipped with a condenser, a nitrogen inlet tube, a thermometer, and a stirrer. Dry nitrogen was passed through the reaction container to remove air. The reaction container was heated to 40° C. and stirred evenly for 30 min. Then, a diisocyanate compound (4,4′-diisocyanate) was added. 49g of cyclohexylmethane diisocyanate) was added, the temperature of the reaction container was controlled at 80°C, and the mixture was stirred at a constant temperature for 2h. Then, a mixed solution consisting of 320g of solvent (dimethylformamide) and 5g of chain extender (ethylene glycol) was slowly added over 5min, and the mixture was stirred for another 30min. Then, 21g of diisocyanate compound (4,4'-dicyclohexylmethane diisocyanate) was added, and the reaction was continued at 80°C for 1h. Then, 0.003g of catalyst (dibutyltin dilaurate, DY-12) was added, and the reaction was continued at 80°C for 2h to obtain an isocyanate-terminated silicone-modified polyurethane prepolymer.

[0105] (2) The isocyanate-terminated organosilicon-modified polyurethane prepolymer obtained in step (1) is cooled to 65° C., 34.8 g of hydroxy acrylate (hydroxyethyl methacrylate) is added dropwise, and the end-capping reaction is carried out for 3 hours to obtain a mixed solution containing a product. The mixed solution containing the product is placed in a reaction vessel equipped with a vacuum tube, a thermometer and a stirrer, and the air in the reaction vessel is evacuated with a vacuum pump to maintain a negative pressure (vacuum degree of -0.1 MPa). At the same time, the temperature is adjusted to 60° C. and the mixed solution containing the product is stirred and pumped until bubbling occurs, and the solvent and small molecular substances are removed to obtain the organosilicon-modified aliphatic polyurethane acrylate resin A.

[0106] The viscosity of the organosilicon-modified aliphatic polyurethane acrylate resin A at 25° C. is 83800 mPa·s. The organosilicon-modified aliphatic polyurethane acrylate resin, the photoinitiator 184 and the photoinitiator TPO in a mass ratio of 100:0.2:0.2 are mixed and cured by ultraviolet light (ultraviolet lamp power: 60 W, light energy 4000 mJ / cm 2 ) After testing, the elongation at break was 480% (the test sample had a thickness of 250 μm) and the hardness was 78A.

[0107] Preparation Example 2

[0108] This preparation example provides an organosilicon-modified aliphatic polyurethane acrylate resin, specifically an organosilicon-modified aliphatic polyurethane acrylate resin B, and the organosilicon-modified aliphatic polyurethane acrylate resin B is prepared by the following method:

[0109] (1) In a reaction vessel equipped with a condenser, a nitrogen inlet tube, a thermometer and a stirrer, 175 g of polyethylene adipate diol (number average molecular weight 1500), 50 g of polyneopentyl adipate diol (number average molecular weight 3000), 15 g of terminal carbon hydroxyl polydimethylsiloxane (number average molecular weight 2000), 0.20 g of antioxidant (triphenyl phosphite), and 240 g of solvent (dimethylformamide) were added, and the air in the reaction vessel was removed by passing dry N2, heated to 30°C, and stirred evenly for 40 minutes; then, diisocyanate was added 42g of isophorone diisocyanate (isophorone diisocyanate) was added, the temperature of the reaction container was controlled at 82°C, and the mixture was stirred at a constant temperature for 3h. Then, a mixed solution consisting of 320g of solvent (dimethylformamide) and 5g of chain extender (ethylene glycol) was slowly added over 5min, and the mixture was stirred for another 35min. Then, 18g of diisocyanate compound (isophorone diisocyanate) was added, and the mixture was kept at 82°C for 1.2h. Then, 0.003g of catalyst (dibutyltin dilaurate) was added, and the mixture was kept at 82°C for 2.5h to obtain an isocyanate-terminated silicone-modified polyurethane prepolymer.

[0110] (2) The isocyanate-terminated organosilicon-modified polyurethane prepolymer obtained in step (1) is cooled to 62° C., 34.8 g of hydroxy acrylate (hydroxyethyl methacrylate) is added dropwise, and the end-capping reaction is carried out for 2 hours to obtain a mixed solution containing a product. The mixed solution containing the product is placed in a reaction vessel equipped with a vacuum tube, a thermometer and a stirrer, and the air in the reaction vessel is evacuated with a vacuum pump to maintain a negative pressure (vacuum degree of -0.1 MPa), while the temperature is raised to 60° C. and the mixed solution containing the product is stirred and pumped until bubbling occurs, and the solvent and small molecules are removed to obtain the organosilicon-modified aliphatic polyurethane acrylate resin B.

[0111] The viscosity of the organosilicon-modified aliphatic polyurethane acrylate resin B at 25° C. is 75600 mPa·s. The organosilicon-modified aliphatic polyurethane acrylate resin, the photoinitiator 184 and the photoinitiator TPO in a mass ratio of 100:0.2:0.2 are mixed and cured by ultraviolet light (ultraviolet lamp power: 60 W, light energy 4000 mJ / cm 2 ) After testing, the elongation at break was 450% and the hardness was 73A.

[0112] Preparation Example 3

[0113] This preparation example provides a silicone-modified aliphatic polyurethane acrylate resin, specifically silicone-modified aliphatic polyurethane acrylate resin C, which differs from Preparation Example 1 only in that the mass of polyethylene adipate glycol (number average molecular weight 1000) in step (1) is adjusted to 182 g, and the mass of terminal carbon hydroxyl polydimethylsiloxane (number average molecular weight 1000) is adjusted to 28 g.

[0114] The viscosity of the prepared silicone-modified aliphatic polyurethane acrylate resin C at 25°C was 80200 mPa·s. The silicone-modified aliphatic polyurethane acrylate resin, photoinitiator 184 and photoinitiator TPO were mixed in a mass ratio of 100:0.2:0.2 and cured by ultraviolet light (ultraviolet lamp power: 60 W, light energy 4000 mJ / cm 2 ) After testing, the elongation at break was 460% and the hardness was 75A.

[0115] The other conditions were the same as those in Preparation Example 1.

[0116] Example 1

[0117] The present embodiment provides a packaging film adhesive composition, a packaging film and a preparation method thereof, wherein the packaging film adhesive composition comprises the following components in parts by weight: 16 parts of an organosilicon-modified aliphatic polyurethane acrylate resin (organosilicon-modified aliphatic polyurethane acrylate resin A provided in Preparation Example 1), 0.3 parts of a UV-active diluent (glycidyl methacrylate), 41 parts of an epoxy resin (bisphenol A epoxy resin 1, bisphenol F epoxy resin, alicyclic epoxy resin and tetrafunctional epoxy resin in a mass ratio of 5:5:7:2), 3 parts of a toughening agent (polyester polyol), 30 parts of a curing agent (methyl hexahydrophthalic anhydride), 0.87 parts of an accelerator (tetrabutylammonium bromide), 10 parts of a light diffusion powder (organosilicon microspheres), 0.86 parts of a coupling agent (γ-(methyl)acryloxypropyltrimethoxysilane) and 0.3 parts of a photoinitiator (184 and TPO in a mass ratio of 2:1).

[0118] The encapsulation film glue composition is prepared by the following method:

[0119] (I) adding a silicone-modified aliphatic polyurethane acrylate resin, UV-active diluent, epoxy resin, toughening agent, light diffusion powder, coupling agent, and photoinitiator into a high-speed disperser, and dispersing for 1.5 hours at room temperature (25° C.) to obtain a premix;

[0120] (II) Grind and disperse the premix prepared in step (I) using a ceramic three-roll mill, grind and disperse for 3 times, cool to room temperature (25°C), add a curing agent and an accelerator, and stir and mix for 30 minutes, then place in a vacuum degassing box, and evacuate for 60 minutes at a vacuum degree of -0.1 MPa to obtain the encapsulation film glue composition.

[0121] The encapsulation film, such as Figure 1 As shown, it includes a first release film layer 1, a packaging film adhesive layer 2 and a second release film layer 3 which are stacked in sequence, the first release film layer 1 is a light release film with a thickness of 100 μm and a release force of 8 gf / in; the packaging film adhesive layer 2 has a thickness of 100 μm; the second release film layer 3 is a heavy release film with a thickness of 100 μm and a release force of 25 gf / in.

[0122] The method for preparing the packaging film comprises the following steps:

[0123] The above-mentioned encapsulation film glue composition was added to the glue tank of the coating equipment, coated on the light release film, and cured by Philips UV lamp light box (UV lamp power: 60W, light energy 4000mJ / cm 2 ), forming a packaging film adhesive layer, laminating a heavy release film on the side of the packaging film adhesive layer away from the light release film, and rolling up to obtain the packaging film.

[0124] Embodiments 2 to 12

[0125] The present embodiments 2 to 12 respectively provide a packaging film glue composition, a packaging film and a preparation method thereof, which adopt the same preparation method as that of embodiment 1, except that the added raw materials and the amounts thereof are calculated in parts by weight, as shown in Tables 2 and 3.

[0126] Table 2

[0127]

[0128]

[0129]

[0130] Table 3

[0131]

[0132]

[0133] Comparative Example 1

[0134] This comparative example provides a packaging film glue composition, a packaging film and a preparation method thereof, which is different from Example 1 only in that the weight proportion of the silicone-modified aliphatic polyurethane acrylate resin (the silicone-modified aliphatic polyurethane acrylate resin A provided in Preparation Example 1) is adjusted to 6 parts, and other conditions are the same as those in Example 1.

[0135] Comparative Example 2

[0136] This comparative example provides a packaging film adhesive composition, a packaging film and a preparation method thereof, which differs from Example 1 only in that the weight proportion of the silicone-modified aliphatic polyurethane acrylate resin (the silicone-modified aliphatic polyurethane acrylate resin A provided in Preparation Example 1) is adjusted to 40 parts, and other conditions are the same as those in Example 1.

[0137] Comparative Example 3

[0138] This comparative example provides a packaging film adhesive composition, a packaging film and a preparation method thereof, which differs from Example 1 only in that the silicone-modified aliphatic polyurethane acrylate resin (the silicone-modified aliphatic polyurethane acrylate resin A provided in Preparation Example 1) is replaced with an aliphatic polyurethane diacrylate of the same mass (brand number 541, Double Bond Chemical Co., Ltd.), and other conditions are the same as in Example 1.

[0139] Comparative Example 4

[0140] This comparative example provides a packaging film adhesive composition, a packaging film and a preparation method thereof, which differs from Example 1 only in that the silicone-modified aliphatic polyurethane acrylate resin (the silicone-modified aliphatic polyurethane acrylate resin A provided in Preparation Example 1) is replaced by a silicone-modified aliphatic polyurethane acrylate resin (the silicone-modified aliphatic polyurethane acrylate resin C provided in Preparation Example 3), and other conditions are the same as those in Example 1.

[0141] The encapsulation film glue compositions and encapsulation films provided in Examples 1 to 12 and Comparative Examples 1 to 4 were subjected to the following performance tests.

[0142] (1) Basic performance testing

[0143] Packaging film status: If the packaging film adhesive layer can be formed and the release film can be torn off without abnormality, it is considered to have good film forming properties; if the adhesive film is soft and sticky and has no shape, and the release film is torn off, it is considered to have poor film forming properties.

[0144] Film peeling force test: According to GB / T 25256-2010 "Test method for 180° peeling force and residual adhesion rate of release film for optical functional films", the 180° film peeling force of the first release film layer and the second release film layer was tested.

[0145] Storage modulus: remove the first and second release film layers from the packaging film, use a rheometer to test the storage modulus of the packaging film adhesive layer, cut the sample into a suitable size according to the size of the rheometer test fixture, and ensure that it covers the test area evenly. Start the rheometer and begin testing under the set temperature, frequency and strain conditions. According to the storage modulus change curve, take the average storage modulus at 25°C.

[0146] Hardness: After baking the packaging film in an oven at 130℃ for 1h, the cured packaging film adhesive layer is laminated to a thickness of 6mm and 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)".

[0147] Adhesion: Tear off the first release film layer in the packaging film, and use a roller to stick the packaging film adhesive layer on the white glass. The laminating pressure is 0.7MPa and the laminating temperature is 80℃. Keep it for 2min. Then bake it in a 130℃ oven for 1h, tear off the second release film layer, and conduct a 100-grid adhesion test according to GB / T 1727-1992 "General Preparation Method for Paint Film".

[0148] Water vapor transmission rate test: After baking the encapsulation film adhesive layer in an oven at 130°C for 1h, refer to GB / T1037-2021 "Test method for water vapor permeability of plastic film and sheet - cup method".

[0149] (2) Fitting and lighting effect test

[0150] Packaging: Tear off the first release film layer of the packaging film, and laminate the Mini LED light board (chip spacing is 0.9mm, chip height is 85μm). The lamination pressure is 0.7MPa and the lamination temperature is 80℃. Maintain for 2min, then bake in a 130℃ oven for 2h to completely cure the packaging film adhesive layer to form a cured adhesive film, remove the second release film layer, obtain the packaged Mini LED module, and perform the following tests.

[0151] Filling effect: Place the above-packaged Mini LED module in a 90°C environment for 5 minutes. If there is no separation or bubbling between the chip and the cured film adhesive layer, the filling is good, otherwise the filling is poor;

[0152] Filling rate: The encapsulation film glue composition is made into a series of encapsulation films whose encapsulation film glue layer thickness is an arithmetic progression, and then the MiniLED light panels with a chip height of X (the chip height used in this test is 85μm) are encapsulated according to the above encapsulation steps. The minimum thickness of the encapsulation film glue layer that can achieve a good filling effect is Y, and the filling rate is recorded as >X / Y×100%.

[0153] Warp: After cutting the process edge of the packaged Mini LED module, lay the display surface of the Mini LED light board flat on an absolutely flat plane, press the diagonal side of the Mini LED light board close to the plane, and then measure the height of the vertex of the pressed diagonal side of the Mini LED light board from the plane, which is the warp data parameter.

[0154] Solvent resistance: Dip a piece of pure cotton cloth in anhydrous ethanol (concentration 99.5%) and wrap it around a 500g standard weight (the contact area after wrapping with cotton cloth is 1cm 2 ), rub back and forth on the sample surface for 50 cycles at a speed of 50 times / minute and a stroke of 20mm. If the cured film has no abnormal phenomena such as whitening, softening, scratches, and no stickiness on the surface, it is considered good; if the cured film has no abnormal phenomena such as whitening, softening, and no stickiness on the surface, it is considered good; if the cured film has no abnormal phenomena such as whitening, softening, and stickiness on the surface, it is considered good; if the cured film has any of the following phenomena, such as whitening, softening, stickiness, and heavy scratches on the surface, it is considered unqualified.

[0155] Environmental reliability test: The packaged Mini LED modules are placed under low temperature, high temperature, high temperature and high humidity, and cold and hot shock conditions. After taking them out, observe whether the packaged Mini LED modules have color changes, cracks on the surface of the cured film, delamination, uneven lighting, or dead lights;

[0156] Low temperature conditions: placed at -40℃ for 500h;

[0157] High temperature conditions: 500h at 95℃;

[0158] High temperature and high humidity conditions: 85°C, 85RH% for 500h;

[0159] Hot and cold shock conditions: -40℃ low temperature for 0.5h, 120℃ high temperature for 0.5h, alternating for 500h.

[0160] The test results are shown in Table 4 or Table 5 below.

[0161] Table 4

[0162]

[0163]

[0164] Table 5

[0165]

[0166]

[0167] In Tables 4 and 5, “ / ” means that the test was not conducted.

[0168] According to the test results of Table 4 and Table 5, the packaging films provided in Examples 1-12 can meet the packaging requirements of Mini LED light boards with a chip spacing of only 0.9 mm and a chip height of 85 μm. The filling effect is good, the filling rate can reach > 85%, and the warping is ≤ 1.8 mm. There are no abnormalities after low temperature, high temperature, high temperature and high humidity, and cold and hot shock tests.

[0169] Compared with Example 1, if the weight percentage of the silicone-modified aliphatic polyurethane acrylate is relatively low (Example 8), the warping of the MiniLED lamp board will be slightly higher after the packaging film encapsulates the MiniLED lamp board; if the weight percentage of the silicone-modified aliphatic polyurethane acrylate is relatively high (Example 9), the filling rate of the packaging film adhesive layer will be relatively low.

[0170] Compared with Example 1, if the weight percentage of the UV active diluent is relatively low (Example 10), the hardness of the packaging film adhesive layer after thermal curing is slightly lower, and the solvent resistance is slightly worse; if the weight percentage of the UV active diluent is relatively high (Example 11), the hardness of the packaging film adhesive layer after thermal curing is slightly higher, and after the packaging film encapsulates the MiniLED lamp board, the warping of the MiniLED lamp board will be slightly higher.

[0171] Compared with Example 1, if the tetrafunctional epoxy resin is not added (Example 12), the hardness of the encapsulating film adhesive layer after thermal curing is slightly lower, the solvent resistance is slightly worse, and the epoxy crosslinking density is low, which ultimately leads to a slightly higher water vapor permeability of the encapsulating film adhesive layer after thermal curing.

[0172] Compared with Example 1, if the weight percentage of the silicone-modified aliphatic polyurethane acrylate resin is too low (Comparative Example 1), the film-forming effect of the encapsulation film glue composition is poor, the obtained encapsulated Mini LED module has large warping and poor environmental reliability.

[0173] Compared with Example 1, if the weight fraction of the silicone-modified aliphatic polyurethane acrylate resin is too high (Comparative Example 2), the performance of the packaging film in terms of film tearing force, hardness, adhesion, filling effect, solvent resistance, environmental reliability, and water vapor transmission rate will deteriorate.

[0174] Compared with Example 1, if the silicone-modified aliphatic polyurethane acrylate resin is replaced with aliphatic polyurethane diacrylate of the same mass (Comparative Example 3), the performance of the packaging film in terms of film tearing force, hardness, adhesion, filling effect, warping, solvent resistance, environmental reliability, and water vapor permeability all deteriorate.

[0175] Compared with Example 1, if the siloxane segment content in the silicone-modified aliphatic polyurethane acrylate resin is too much (Comparative Example 4), the adhesion of the encapsulation film adhesive layer after thermal curing is reduced, and edge cracking and dead light phenomenon are likely to occur after thermal shock.

[0176] The applicant declares that the present invention illustrates the process method of the present invention through the above-mentioned embodiments, but the present invention is not limited to the above-mentioned process steps, that is, it does not mean that the present invention must rely on the above-mentioned process steps to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of the raw materials selected by the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A packaging film glue composition, characterized in that: The encapsulation film glue composition comprises the following components by weight: 10-30 parts of organosilicon-modified aliphatic polyurethane acrylate resin, 0.1-5 parts of UV-active diluent, 30-60 parts of epoxy resin, 2-12 parts of toughening agent, 20-55 parts of curing agent, 0.1-2 parts of accelerator, 5-20 parts of light diffusion powder, 0.02-1.0 parts of coupling agent and 0.05-0.5 parts of photoinitiator; The raw materials for preparing the organosilicon-modified aliphatic polyurethane acrylate resin include polyester diol, terminal carbon hydroxyl polydimethylsiloxane, diisocyanate compound and hydroxy acrylate; The molar ratio of the polyester diol to the terminal carbon hydroxyl polydimethylsiloxane is (15-45):1; The UV-active diluent includes an epoxy acrylate compound.

2. The encapsulation film glue composition according to claim 1, characterized in that: The molar ratio of the diisocyanate compound to the polyester diol is 1:(0.5-1.0); Preferably, the molar ratio of the hydroxy acrylate to the diisocyanate compound is 1:(0.8-1.2); Preferably, the preparation method of the silicone-modified aliphatic polyurethane acrylate resin comprises the following steps: (1) mixing polyester diol, terminal carbon hydroxyl polydimethylsiloxane, and diisocyanate compound, and subjecting them to a condensation reaction to obtain an isocyanate-terminated silicone-modified polyurethane prepolymer; (2) end-capping the isocyanate-terminated organosilicon-modified polyurethane prepolymer obtained in step (1) with hydroxy acrylate to obtain the organosilicon-modified aliphatic polyurethane acrylate resin; Preferably, the polyester diol includes any one of polyethylene adipate diol, polyneopentyl adipate diol, polycaprolactone glycol ester diol, polypropylene adipate diol, polybutylene adipate-1,4-diol or polyneopentyl terephthalate diol or a combination of at least two thereof; Preferably, the diisocyanate compound includes any one or a combination of at least two of 4,4'-dicyclohexylmethane diisocyanate, 2,4-trimethylhexane diisocyanate, methylcyclohexylene diisocyanate, dicyclohexylmethylene diisocyanate, toluene diisocyanate, hexamethylene diisocyanate or isophorone diisocyanate; Preferably, the hydroxyacrylate includes any one or a combination of at least two of hydroxyethyl methacrylate, hydroxyethyl acrylate, hydroxypropyl methacrylate, hydroxypropyl acrylate, hydroxybutyl methacrylate or hydroxybutyl acrylate; Preferably, the condensation reaction temperature in step (1) is 80-85° C. and the reaction time is 2-7 h; Preferably, the end-capping reaction temperature in step (2) is 60-70° C., and the reaction time is 2-4 h.

3. The encapsulation film glue composition according to claim 2, characterized in that: The mixing in step (1) further comprises mixing with an antioxidant, a solvent, a chain extender and a catalyst; Preferably, the antioxidant comprises any one or a combination of at least two of triphenyl phosphite, diisodecyl phosphite, trinonylphenyl phosphite or bisphenol A phosphite; Preferably, the solvent comprises any one or a combination of at least two of dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, N-methylpyrrolidone or tetrahydrofuran; Preferably, the chain extender comprises any one of ethylene glycol, 1,2-propylene glycol, 1,6-hexanediol or diethylene glycol, or a combination of at least two thereof; Preferably, the catalyst comprises any one of dibutyltin dilaurate, dibutyltin diacetate, dioctyltin diacetate, dibutyltin maleate or stannous octoate, or a combination of at least two thereof; Preferably, the mass ratio of the antioxidant to the polyester diol is 0.1:(100-130); Preferably, the mass ratio of the solvent to the polyester diol is (1-3):1; Preferably, the molar ratio of the chain extender to the polyester diol is 1:(1-3); Preferably, the mass of the catalyst is 0.002% to 0.006% of the mass of the diisocyanate compound; Preferably, the preparation method of the silicone-modified aliphatic polyurethane acrylate resin specifically comprises the following steps: (1) A polyester diol, a terminal carbon hydroxyl polydimethylsiloxane, an antioxidant and a part of a solvent are heated to 30-50° C. under nitrogen protection and pre-mixed for 20-40 minutes, a part of a diisocyanate compound is added and reacted at 80-85° C. for 2-3 hours, a mixed solution of the remaining solvent and a chain extender is added, and the temperature is maintained at 80-85° C. for another 30-40 minutes, the remaining diisocyanate compound is added, and the temperature is maintained at 80-85° C. for 1-1.5 hours, a catalyst is added, and the temperature is maintained at 80-85° C. for another 2-2.5 hours to obtain an isocyanate-terminated silicone-modified polyurethane prepolymer; (2) cooling the isocyanate-terminated silicone-modified polyurethane prepolymer obtained in step (1) to 60-65° C., adding hydroxy acrylate, and performing a capping reaction for 2-4 hours to obtain the silicone-modified aliphatic polyurethane acrylate resin; Preferably, the end-capping reaction further includes a post-treatment step, wherein the post-treatment is vacuum rotary evaporation; Preferably, the mass of the solvent in the portion is 20% to 60% of the total mass of the solvent; Preferably, the molar amount of the diisocyanate compound in the part accounts for 65% to 75% of the total molar amount of the diisocyanate compound; Preferably, the viscosity of the silicone-modified aliphatic polyurethane acrylate resin at 25° C. is 20,000 to 110,000 mPa·s; Preferably, the elongation at break of the organosilicon-modified aliphatic polyurethane acrylate resin is 400% to 850%, and the hardness is 40 to 80A.

4. The encapsulation film glue composition according to any one of claims 1 to 3, characterized in that: The weight proportion of the organosilicon-modified aliphatic polyurethane acrylate resin in the encapsulation film glue composition is 15 to 20 parts; Preferably, the weight portion of the UV active diluent in the encapsulation film glue composition is 0.3 to 3 parts; Preferably, the epoxy acrylate compound includes glycidyl methacrylate and / or glycidyl acrylate; Preferably, the UV-active diluent further comprises an acrylate compound free of epoxy groups; Preferably, the epoxy-free acrylate compound includes any one or a combination of at least two of trimethylolpropane triacrylate, pentaerythritol triacrylate, ethoxylated trimethylolpropane triacrylate, 1,6-hexanediol diacrylate, isooctyl acrylate, lauryl acrylate or isobornyl acrylate; Preferably, the epoxy resin comprises a difunctional epoxy resin and / or a tetrafunctional epoxy resin; Preferably, the bifunctional epoxy resin comprises 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, fat-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, fluorine-containing epoxy resin or aliphatic epoxy resin; Preferably, the toughening agent includes any one or a combination of at least two of polyester polyol, acrylic rubber, core-shell structure styrene-butadiene rubber, nitrile rubber modified epoxy resin, polyurethane modified epoxy resin or polyether polyol; Preferably, the polyester polyol comprises polyester diol; Preferably, the curing agent comprises a polyetheramine curing agent and / or an anhydride curing agent; Preferably, the acid anhydride curing agent includes any one of methylhexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, hexahydrophthalic anhydride or tetrahydrophthalic anhydride, or a combination of at least two thereof; Preferably, the 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 or polymethyl methacrylate microspheres, or a combination of at least two thereof; 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 or a combination of at least two of hydroxycyclohexane phenone, 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; Preferably, the encapsulation film adhesive composition further comprises a black pigment.

5. A method for preparing the encapsulation film glue composition according to any one of claims 1 to 4, characterized in that: The preparation method comprises the following steps: mixing organosilicon-modified aliphatic polyurethane acrylate resin, UV-active diluent, epoxy resin, toughening agent, curing agent, accelerator, light diffusion powder, coupling agent and photoinitiator to obtain the encapsulation film glue composition.

6. A packaging film, characterized in that: The packaging film comprises a first release film layer, a packaging film adhesive layer and a second release film layer which are stacked in sequence, and the packaging film adhesive layer is made of the packaging film adhesive composition according to any one of claims 1 to 4.

7. The packaging film according to claim 6, characterized in that: The thickness of the encapsulation film adhesive layer is 50 to 500 μm; Preferably, the first release film layer and the second release film layer independently include any one of a silicone release film, a non-silicone release film or a fluorine release film, or a combination of at least two thereof; Preferably, the first release film layer comprises a light release film, and the second release film layer comprises a heavy release film; Preferably, the light release film has a thickness of 25 to 125 μm and a release force of 1 to 15 gf / in; Preferably, the heavy release film has a thickness of 75 to 188 μm and a release force of 15 to 40 gf / in; Preferably, the release force of the light release film and the heavy release film differs by 5 to 40 gf / in.

8. A method for preparing a packaging film according to claim 6 or 7, characterized in that: The preparation method comprises the following steps: coating the encapsulation film adhesive composition as described in any one of claims 1 to 4 on one side of the first release film layer, curing with ultraviolet light to form an encapsulation film adhesive layer, and laminating a second release film layer on the side of the encapsulation film adhesive layer away from the first release film layer to obtain the encapsulation film.

9. The preparation method according to claim 8, characterized in that: The coating comprises any one of slit coating, comma blade coating, screen coating, micro-dimple coating, transfer coating or spray coating, or a combination of at least two thereof; Preferably, the light source for UV curing includes any one of a low-pressure mercury lamp, an ultraviolet lamp tube, and an ultraviolet LED lamp, or a combination of at least two thereof; Preferably, the UV light intensity of the UV curing is 30 to 1000 mW / cm 2 ; Preferably, the energy of the ultraviolet light used for the ultraviolet curing is 2500-5000 mJ / cm 2 .

10. Application of the packaging film according to claim 6 or 7 in LED direct display module packaging; Preferably, the LED direct display module is a Mini LED direct display module; Preferably, the LED direct display module packaging includes roll-bonding packaging or hot-pressing packaging; Preferably, the roll-bonding packaging specifically includes the following steps: removing the first release film layer of the packaging film, then rolling-bonding the packaging film with the MiniLED direct display module, baking, removing the second release film layer, and completing the roll-bonding packaging; Preferably, the roller lamination is performed on a roller lamination device, and the pressure applied by the rubber roller of the roller lamination device is greater than 0.6 kg / cm 2 ; Preferably, the rolling speed of the rubber roller of the rolling equipment is less than 2m / min; Preferably, the baking temperature in the roll-pressed packaging is 130-140° C. and the baking time is 0.5-2 h; Preferably, the hot pressing and laminating packaging specifically comprises the following steps: removing the first release film layer of the packaging film, pasting the chip located on the top of the Mini LED direct display module, and then placing it in a laminating machine with a vacuum cavity, laminating and baking under vacuum, heating and pressurizing conditions, removing the second release film layer, and completing the roll laminating packaging; Preferably, the vacuum degree of the vacuum is -0.09 to -0.1 MPa; Preferably, the heating temperature is 25 to 90°C; Preferably, the pressurized pressure is 0.1 to 1.5 MPa; Preferably, the baking temperature in the thermal compression bonding package is 130-140° C. and the baking time is 0.5-2 h.

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