Brightness enhancement film glue, preparation method of brightness enhancement film glue, brightness enhancement film and application of brightness enhancement film glue

Abstract

The invention provides a brightness enhancement film glue and a preparation method thereof, a brightness enhancement film and application thereof, and relates to the technical field of brightness enhancement films.The brightness enhancement film glue comprises a component A, a component B, a component C and a component D; the component A is a bifunctional acrylate monomer with elastic resilience; the component A comprises a component A1; the component A1 is selected from acrylate monomers containing propylene oxidation chain segments; the component B is a bifunctional bisphenol A di (methyl) acrylate monomer and / or a bisphenol A epoxy resin main chain di (methyl) acrylate oligomer; the component C is a monofunctional acrylate monomer; and the component D is a photoinitiator. The problem of optical bright lines caused by the fact that water drops extend along the grooves of the brightness enhancement film in the liquid crystal display is solved, and the technical effects that the water drops are prevented from extending along the grooves of the brightness enhancement film, and the problem of optical bright lines is avoided are achieved.

Description

Technical Field

[0001] This invention relates to the technical field of brightness enhancement films, and in particular to a brightness enhancement film adhesive, its preparation method, the brightness enhancement film itself, and its applications. Background Technology

[0002] The backlight module of a TFT-LCD includes components such as a light source, light guide plate, diffuser film, brightness enhancement film, and reflective film. Its main function is to provide a uniform surface light source for the LCD panel. The brightness enhancement film is an optical thin film with a prism-like cross-section, which can concentrate light from different emission directions on the front side, thereby improving the brightness of the LCD display panel.

[0003] Currently, the polymerizable composition used for molding the prism structure in brightness enhancement films is a UV-curable acrylic resin adhesive. Optical films manufactured on PET substrates using UV curing have a surface with a microprism structure approximately 10-50 micrometers in height. For brightness enhancement films used in large-size LCD displays (e.g., televisions, educational displays), the UV adhesive formulation can be designed to create films with elastic recovery capabilities (or high resilience). The prism structure surface does not require an additional protective film, thus addressing scratches and abrasions during transportation and cutting.

[0004] After being assembled into an LCD monitor, the backlight module comes into contact with the monitor's bezel and, if not properly sealed, remains open to the ambient air. In humid and hot climates, the internal space of the LCD monitor contains a high concentration of water vapor, and the film also absorbs a significant amount of moisture. When the outside temperature drops, the low temperature is conducted to the TV bezel, where it condenses into water droplets inside. These droplets come into contact with the edge of the brightness enhancement film and can then spread towards the center of the film through the grooves in the film's prism structure, optically forming bright lines that affect light path propagation and further impact the image display.

[0005] LCD manufacturers mitigate the effects of ocean shipping or humid and hot environments by adding sealed bags and desiccants to the packaging. However, during consumer use, bright lines caused by water droplets spreading in the brightness enhancement film grooves due to moisture intrusion are still common.

[0006] In view of this, the present invention is hereby proposed. Summary of the Invention

[0007] One of the objectives of this invention is to provide a brightness enhancement film adhesive. The liquid refractive index of the brightness enhancement film adhesive can be ≥1.51. The high refractive index brings high brightness gain. The formed brightness enhancement film can take into account both excellent elastic recovery and strength, and also has good hydrophobicity, which can prevent water droplets from spreading along the grooves of the brightness enhancement film and avoid the problem of optical bright lines.

[0008] The second objective of this invention is to provide a method for preparing a brightening film adhesive that is simple, efficient, and suitable for industrial production.

[0009] The third objective of this invention is to provide a brightness enhancement film with a high refractive index that results in high luminance gain, while also possessing excellent elastic resilience and strength, as well as good hydrophobicity, which can prevent water droplets from spreading along the grooves of the brightness enhancement film and avoid the problem of optical bright lines.

[0010] The fourth objective of this invention is to provide an application of a brightness enhancement film that solves the problem of bright lines caused by water droplets spreading along the grooves of the brightness enhancement film inside the liquid crystal display.

[0011] In order to achieve the above-mentioned objectives of the present invention, the following technical solution is adopted: In a first aspect, a brightening film adhesive includes component A, component B, component C, and component D; Component A is a bifunctional acrylate monomer with elastic recovery properties; Component A includes component A1; The A1 component is selected from acrylate monomers containing propylene oxide segments; Component B is a bifunctional bisphenol A di(meth)acrylate monomer and / or a di(meth)acrylate oligomer of the bisphenol A epoxy resin backbone. Component C is a monofunctional acrylate monomer; Component D is a photoinitiator.

[0012] Furthermore, component A1 is selected from any of the following acrylate monomers: AA-(PO) a -AA, 10≤a≤30; AA-(PO) b -R1-(PO) c -AA, 10≤b+c≤30; AA-(EO) d -(PO) e -R2-(PO) f -(EO) g -AA, d+g≤10, 10≤e+f, d+g+e+f≤30; AA-(PO) e -(EO) d -R3-(EO) g -(PO) f -AA, d+g≤10, 10≤e+f, d+g+e+f≤30; R1, R2, and R3 are each independently selected from bisphenol A, bisphenol fluorene, ethylene glycol, propylene glycol, butanediol, pentanediol, hexanediol, nonanediol, decanediol, undecyldiol, dodecyldiol, tridecyldiol, tetradecyldiol, or pentadecyldiol.

[0013] Furthermore, component A also includes component A2; The A2 component is selected from acrylate monomers containing ethoxylated segments; Preferably, component A2 is selected from any one of the following acrylate monomers: AA-(EO) h -AA, 5≤h≤10; AA-(EO) i -R4-(EO) j -AA, 5≤i+j≤10; R4 is selected from bisphenol A, bisphenol fluorene, ethylene glycol, propylene glycol, butanediol, pentanediol, hexanediol, nonanediol, decanediol, undecyldiol, dodecyldiol, tridecyldiol, tetradecyldiol, or pentadecyldiol.

[0014] Furthermore, component A also includes component A3; The A3 component is selected from acrylate monomers containing propylene oxide segments; Preferably, the A3 component is selected from any one of the following acrylate monomers: AA-(PO) k -AA, 5≤k≤10; AA-(PO) m -R5-(PO) n -AA, 5≤m+n≤10; R5 is selected from bisphenol A, bisphenol fluorene, ethylene glycol, propylene glycol, butanediol, pentanediol, hexanediol, nonanediol, decanediol, undecyldiol, dodecyldiol, tridecyldiol, tetradecyldiol, or pentadecyldiol.

[0015] Furthermore, the bisphenol A di(meth)acrylate monomer includes at least one of BPA(2EO)DA, BPA(3EO)DA, BPA(4EO)DA, BPA(2EO)DMA, BPA(3EO)DMA, and BPA(4EO)DMA; Preferably, the di(meth)acrylate oligomer of the bisphenol A epoxy resin backbone includes at least one of bisphenol A di(meth)acrylate oligomer and bisphenol A di(meth)acrylate oligomer modified with flexible segments; Preferably, the monofunctional acrylate monomer includes at least one of dibenzofuran methacrylate, biphenyl methacrylate, o-phenylphenoxyethyl acrylate, o-phenylphenoxyethyl ethoxy acrylate, phenoxyphenyl methacrylate, phenoxyethyl acrylate, and benzyl acrylate. Preferably, the photoinitiator includes at least one of photoinitiator 1173, photoinitiator 184, photoinitiator MBF, photoinitiator TPO, photoinitiator TPO-L, and photoinitiator BAPO.

[0016] Furthermore, the brightening film adhesive also includes component E; Component E is an auxiliary agent; Preferably, the additives include at least one of ultraviolet absorbers, antistatic agents, defoamers, and slip agents.

[0017] Furthermore, the brightening film adhesive comprises the following components in 100 parts by total weight: Component A: 25-45 parts, Component B: 10-30 parts, Component C: 25-50 parts, Component D: 1-5 parts, and Component E: less than 1 part.

[0018] Secondly, a method for preparing the brightening film adhesive according to any one of the above claims includes the following steps: The components are mixed to obtain the brightening film adhesive.

[0019] Thirdly, a brightening film is formed by UV curing of the brightening film adhesive described in any of the above-mentioned claims.

[0020] Fourthly, the application of the aforementioned brightness enhancement film in a liquid crystal display.

[0021] Compared with the prior art, the present invention has at least the following beneficial effects: The brightness enhancement film adhesive provided by this invention has a liquid refractive index of ≥1.51, and the high refractive index brings high brightness gain. The brightness enhancement film made with this adhesive can take into account both excellent elastic recovery and strength, ensuring that no wear occurs during transportation or cutting. The adhesive also has good hydrophobicity, which can prevent water droplets from spreading along the grooves of the brightness enhancement film and avoid the problem of optical bright lines.

[0022] The method for preparing the brightening film adhesive provided by this invention is simple, efficient, and suitable for industrial production.

[0023] The brightness enhancement film provided by this invention has a high refractive index, resulting in high luminance gain. It can also balance excellent elastic recovery and strength, and has good hydrophobicity, which can prevent water droplets from spreading along the grooves of the brightness enhancement film and avoid the problem of optical bright lines.

[0024] The application of the brightness enhancement film provided by this invention solves the problem of bright lines caused by water droplets spreading along the grooves of the brightness enhancement film inside the liquid crystal display. Detailed Implementation The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] According to a first aspect of the present invention, a brightening film adhesive is provided, comprising component A, component B, component C and component D; Component A is a bifunctional acrylate monomer with elastic recovery properties; Component A includes component A1; Component A1 is selected from acrylate monomers containing propylene oxide segments; Component B is a difunctional bisphenol A di(meth)acrylate monomer and / or a di(meth)acrylate oligomer of the bisphenol A epoxy resin backbone; Component C is a monofunctional acrylate monomer; Component D is a photoinitiator.

[0026] The refractive index of the brightness enhancement film adhesive of this invention can be ≥1.51, and the high refractive index brings high brightness gain; thus, the brightness enhancement film made with the brightness enhancement film adhesive can take into account both excellent elastic recovery and strength, ensuring that no wear occurs during transportation or cutting; the brightness enhancement film adhesive has good hydrophobicity, which can prevent water droplets from spreading along the grooves of the brightness enhancement film and avoid the problem of optical bright lines.

[0027] In this invention, component A comprises one or more bifunctional propylene ester monomers and has an ethoxylation segment (CH2CH2O) in its molecular structure. m and / or propionyl oxide segments (CH(CH3)CH2O) n It should be noted that the ethoxylated segment is usually obtained by ring-opening ethylene oxide, denoted by EO. The propylene oxide segment is usually obtained by ring-opening propylene oxide and is denoted by PO. The propylene oxide segment exhibits significantly improved hydrophobicity compared to the ethoxide segment. This is because the propylene oxide segment involves the substitution of a methylene hydrogen atom on the ethyl group by a methyl group, which provides steric protection for the ether group on the side group. The acrylate group is represented by AA. .

[0028] The flexible segments of component A1 contain propionyl oxide segments, and the total number of PO on each molecule is greater than or equal to 10 and less than or equal to 30, which gives the prism film better elastic recovery and better hydrophobic properties. Component A1 may also contain repeating units of ethoxylate segments, but the total number of EO on each molecule is less than or equal to 10, the total number of PO on each molecule is greater than or equal to 10, and the sum of the total number of EO and PO on each molecule is less than or equal to 30.

[0029] In a preferred embodiment, component A1 can be selected from any of the following acrylate monomers: AA-(PO) a -AA, 10≤a≤30; AA-(PO) b -R1-(PO) c -AA, 10≤b+c≤30; AA-(EO) d -(PO) e -R2-(PO) f -(EO) g -AA, d+g≤10, 10≤e+f, d+g+e+f≤30; AA-(PO) e -(EO) d -R3-(EO) g -(PO) f -AA, d+g≤10, 10≤e+f, d+g+e+f≤30; R1, R2, and R3 are each independently selected from bisphenol A, bisphenol fluorene, ethylene glycol, propylene glycol, butanediol, pentanediol, hexanediol, nonanediol, decanediol, undecyldiol, dodecyldiol, tridecyldiol, tetradecyldiol, or pentadecyldiol.

[0030] In a preferred embodiment, component A may further include component A2.

[0031] The flexible segments on the A2 component may contain only ethoxylated segments, and the total number of EOs on each molecule is greater than or equal to 5 and less than or equal to 10.

[0032] In a preferred embodiment, component A2 can be selected from any of the following acrylate monomers: AA-(EO) h -AA, 5≤h≤10; AA-(EO) i -R4-(EO) j -AA, 5≤i+j≤10; R4 is selected from bisphenol A, bisphenol fluorene, ethylene glycol, propylene glycol, butanediol, pentanediol, hexanediol, nonanediol, decanediol, undecyldiol, dodecyldiol, tridecyldiol, tetradecyldiol, or pentadecyldiol.

[0033] In a preferred embodiment, component A may further comprise component A3.

[0034] The flexible segments on the A3 component may contain only propionyl oxide segments, and the total number of PO on each molecule is greater than or equal to 5 and less than or equal to 10.

[0035] In a preferred embodiment, component A3 can be selected from any of the following acrylate monomers: AA-(PO) k -AA, 5≤k≤10; AA-(PO) m -R5-(PO) n -AA, 5≤m+n≤10; R5 is selected from bisphenol A, bisphenol fluorene, ethylene glycol, propylene glycol, butanediol, pentanediol, hexanediol, nonanediol, decanediol, undecyldiol, dodecyldiol, tridecyldiol, tetradecyldiol, or pentadecyldiol.

[0036] In a preferred embodiment, the bisphenol A di(meth)acrylate monomer includes, but is not limited to, at least one of BPA(2EO)DA, BPA(3EO)DA, BPA(4EO)DA, BPA(2EO)DMA, BPA(3EO)DMA and BPA(4EO)DMA, having a refractive index greater than or equal to 1.53 at 25°C.

[0037] In a preferred embodiment, the di(meth)acrylate oligomer of the bisphenol A epoxy resin backbone includes, but is not limited to, at least one of standard bisphenol A di(meth)acrylate oligomers and bisphenol A di(meth)acrylate oligomers modified with flexible segments.

[0038] In this invention, the flexible segment modification can be caprolactone modification or fatty acid modification; the standard bisphenol A di(meth)acrylate oligomer has a refractive index greater than or equal to 1.55 at 25°C; the flexible segment modified bisphenol A di(meth)acrylate oligomer has a refractive index greater than or equal to 1.52.

[0039] In a preferred embodiment, the monofunctional acrylate monomer includes, but is not limited to, at least one of dibenzofuran methacrylate (DBFMA), biphenyl methacrylate (BPMA), o-phenylphenoxyethyl acrylate (OPPEA), o-phenylphenoxyethyl ethoxy acrylate (OPP(EO)2A), phenoxyphenyl methacrylate (PBA), phenoxyethyl acrylate (PHEA), and benzyl acrylate (BZA), with a refractive index greater than or equal to 1.51, providing a lower viscosity and facilitating the acquisition of a lower formulation viscosity.

[0040] In this invention, the refractive index of the formulation can be adjusted from 1.51 to 1.615 by varying the benzene ring structure and number of benzene rings on the monofunctional acrylate monomer. The monofunctional acrylate monomer does not generate crosslinking points in the polymerized film-forming material. The acrylate groups are attached to the molecular backbone, and the structural units attached to the acrylate become side groups of the molecular backbone. While ensuring a high refractive index, it also maintains good molecular chain mobility, which is beneficial for obtaining a brightening film with good elastic recovery.

[0041] In a preferred embodiment, the photoinitiator includes, but is not limited to, at least one of 2-hydroxy-2-methyl-1-phenyl-1-propanone (1173), 1-hydroxycyclohexylphenyl ketone (184), methyl benzoylformate (MBF), diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (TPO), phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide (BAPO, 819), and ethyl 2,4,6-trimethylbenzoylphenylphosphonate (TPO-L).

[0042] The photoinitiator can be a combination of two photoinitiators: one is a photoinitiator 1173, 184 or MBF that has strong absorption in the UV band below 365nm, and the other is a photoinitiator TPO, TPO-L or BAPO that has strong absorption in the UV band above 365nm.

[0043] In a preferred embodiment, the brightening film adhesive may also contain component E.

[0044] In a preferred embodiment, component E may be an auxiliary agent, which may be added as needed for the formulation application, including but not limited to at least one of ultraviolet absorbers, antistatic agents, defoamers, and slip agents.

[0045] Ultraviolet absorbers enable the brightening film to maintain a low yellowing value during sunlight exposure or blue light aging tests; antistatic agents reduce the accumulation of static electricity on the film, improving the effect of cutting film shavings or reducing dust adsorption on the film; defoamers inhibit or eliminate air bubbles in the adhesive during the production process of the brightening film structural layer; slip agents improve the slip properties of the brightening film structural layer, contributing to the anti-friction properties of the brightening film, with polyether-modified silicone slip agents being preferred.

[0046] In a preferred embodiment, the brightening film adhesive comprises the following components in 100 parts by total weight: Component A: 25-45 parts, Component B: 10-30 parts, Component C: 25-50 parts, Component D: 1-5 parts, and Component E: less than 1 part.

[0047] In this invention, typical but non-limiting weight parts of component A are, for example, 25 parts, 30 parts, 35 parts, 40 parts, and 45 parts; typical but non-limiting weight parts of component B are, for example, 10 parts, 15 parts, 20 parts, 25 parts, and 30 parts; typical but non-limiting weight parts of component C are, for example, 25 parts, 30 parts, 35 parts, 40 parts, 45 parts, and 50 parts; typical but non-limiting weight parts of component D are, for example, 1 part, 2 parts, 3 parts, 4 parts, and 5 parts; and typical but non-limiting weight parts of component E are, for example, 0.1 parts, 0.3 parts, 0.5 parts, 0.7 parts, and 0.9 parts.

[0048] In this invention, component A1 can be 10 to 30 parts; component A2 can be less than or equal to 15 parts; component A3 can be less than or equal to 30 parts; and the sum of components A2 and A3 can be less than or equal to 30 parts.

[0049] In this invention, if the amount of component C is less than 25 parts, a suitable operating viscosity cannot be guaranteed; if the amount of component C is greater than 50 parts, it contains too many monofunctional acrylate monomers, affecting the overall mechanical strength deviation; if the amount of photoinitiator is less than 1 part, the curing speed will be too slow, affecting production efficiency; if the amount of photoinitiator is greater than 5 parts, it will result in more residue in the cured product, affecting performance.

[0050] According to a second aspect of the present invention, a method for preparing the brightening film adhesive according to any one of the above claims is provided, comprising the following steps: The components are mixed to obtain the brightening film adhesive.

[0051] The method for preparing the brightening film adhesive of this invention is simple, efficient, and suitable for industrial production.

[0052] According to a third aspect of the present invention, a brightening film is provided, which is formed by UV curing of the brightening film adhesive described in any of the above claims.

[0053] The high refractive index of the brightness enhancement film of this invention brings high luminance gain, while also taking into account excellent elastic recovery and strength. It also has good hydrophobicity, which can prevent water droplets from spreading along the grooves of the brightness enhancement film and avoid the problem of optical bright lines.

[0054] According to a fourth aspect of the present invention, an application of the above-described brightness enhancement film in a liquid crystal display is provided.

[0055] The application of the brightness enhancement film in this invention solves the problem of bright lines caused by water droplets spreading along the grooves of the brightness enhancement film inside the liquid crystal display.

[0056] The present invention will be further illustrated below through examples. Unless otherwise specified, the materials in the examples are prepared according to existing methods or purchased directly from the market, and the main raw materials are as follows.

[0057]

[0058] Example 1 A brightening film adhesive has a refractive index of 1.536 at 25°C. The formulation is shown in Table 1 and includes the following components by weight: 25 parts of polypropylene glycol (700) diacrylate (EM2208), 20 parts of (4) bisphenol A diacrylate (EM2261), 50 parts of o-phenylphenoxy ethyl acrylate (M1142), 2.5 parts of photoinitiator 184, 2 parts of photoinitiator TPO and 0.5 parts of silicone slip agent BYK333.

[0059] Example 2 A brightening film adhesive has a refractive index of 1.537 at 25°C. The formulation is shown in Table 1 and includes the following components by weight: 10 parts of polypropylene glycol (400) diacrylate (M2040), 10 parts of polypropylene glycol (700) diacrylate (EM2208), 15 parts of (10) ethoxylated bisphenol A diacrylate (EM2265), 10 parts of (4) ethoxylated bisphenol A diacrylate (EM2261), 50 parts of o-phenylphenoxyethyl acrylate (M1142), 2.5 parts of photoinitiator 184, 2 parts of photoinitiator TPO and 0.5 parts of silicone slip agent BYK333.

[0060] Example 3 A brightening film adhesive has a refractive index of 1.535 at 25°C. The formulation is shown in Table 1 and includes the following components by weight: 20 parts of polypropylene glycol (700) diacrylate (EM2208), 15 parts of (10) ethoxylated bisphenol A diacrylate (EM2265), 10 parts of (4) ethoxylated bisphenol A diacrylate (EM2261), 10 parts of bisphenol A epoxy acrylate oligomer (CN104), 41.5 parts of o-phenylphenoxy ethyl acrylate (M1142), 1.5 parts of photoinitiator 184, 1.5 parts of photoinitiator TPO and 0.5 parts of silicone slip agent BYK333.

[0061] Example 4 A brightening film adhesive has a refractive index of 1.523 at 25°C. The formulation is shown in Table 1 and includes the following components by weight: 30 parts of polypropylene glycol (700) diacrylate (EM2208), 5 parts of (10) bisphenol A diacrylate (EM2265), 30 parts of (4) bisphenol A diacrylate (EM2261), 33.5 parts of o-phenylphenoxyethyl acrylate (M1142), 0.5 parts of photoinitiator 184, 0.5 parts of photoinitiator TPO and 0.5 parts of silicone slip agent BYK333.

[0062] Example 5 A brightening film adhesive has a refractive index of 1.522 at 25°C. The formulation is shown in Table 1 and includes the following components by weight: 21.5 parts of polypropylene glycol (400) diacrylate (M2040), 15 parts of polypropylene glycol (700) diacrylate (EM2208), 5 parts of (10) ethoxylated bisphenol A diacrylate (EM2265), 10 parts of (4) ethoxylated bisphenol A diacrylate (EM2261), 45 parts of o-phenylphenoxyethyl acrylate (M1142), 1.5 parts of photoinitiator 184, 1.5 parts of photoinitiator TPO and 0.5 parts of silicone slip agent BYK333.

[0063] Example 6 A brightening film adhesive has a refractive index of 1.519 at 25°C. The formulation is shown in Table 1 and includes the following components by weight: 30 parts of polypropylene glycol (400) diacrylate (M2040), 11.5 parts of polypropylene glycol (700) diacrylate (EM2208), 20 parts of bisphenol A epoxy acrylate oligomer (CN104), 35 parts of o-phenylphenoxy ethyl acrylate (M1142), 1.5 parts of photoinitiator 184, 1.5 parts of photoinitiator TPO, and 0.5 parts of silicone slip agent BYK333.

[0064] Example 7 A brightening film adhesive has a refractive index of 1.521 at 25°C. The formulation is shown in Table 1 and includes the following components by weight: 15 parts of polypropylene glycol (400) diacrylate (M2040), 15 parts of polypropylene glycol (700) diacrylate (EM2208), 15 parts of (10) ethoxylated bisphenol A diacrylate (EM2265), 10 parts of (4) ethoxylated bisphenol A diacrylate (EM2261), 16.5 parts of bisphenol A epoxy acrylate oligomer (CN104), 25 parts of o-phenylphenoxy ethyl acrylate (M1142), 1.5 parts of photoinitiator 184, 1.5 parts of photoinitiator TPO and 0.5 parts of silicone slip agent BYK333.

[0065] Example 8 This embodiment provides a brightening film adhesive, which differs from Embodiment 1 only in that (4) bisphenol A diacrylate ethoxylate (EM2261) is replaced in equal amounts with bisphenol A epoxy acrylate oligomer (CN104). The remaining components and their quantities are the same as in Example 1.

[0066] Example 9 This embodiment provides a brightening film adhesive, which differs from Embodiment 1 only in that o-phenylphenoxyethyl acrylate (M1142) is replaced with dibenzofuran methacrylate in an equal amount; The remaining components and their quantities are the same as in Example 1.

[0067] Example 10 This embodiment provides a brightening film adhesive, which differs from Embodiment 1 only in that o-phenylphenoxyethyl acrylate (M1142) is replaced with benzyl acrylate in an equal amount; The remaining components and their quantities are the same as in Example 1.

[0068] Comparative Example 1 A brightening film adhesive, with a refractive index of 1.547 at 25°C, has a formulation shown in Table 2, comprising the following components by weight: 25 parts of (30) bisphenol A diacrylate (M2300), 20 parts of (4) bisphenol A diacrylate (EM2261), 50 parts of o-phenylphenoxyethyl acrylate (M1142), 2.5 parts of photoinitiator 184, 2 parts of photoinitiator TPO and 0.5 parts of silicone slip agent BYK333.

[0069] Comparative Example 2 A brightening film adhesive has a refractive index of 1.544 at 25°C. The formulation is shown in Table 2 and includes the following components by weight: 20 parts of (30) bisphenol A diacrylate ethoxylate (M2300), 15 parts of (10) bisphenol A diacrylate ethoxylate (EM2265), 10 parts of (4) bisphenol A diacrylate ethoxylate (EM2261), 10 parts of bisphenol A epoxy acrylate oligomer (CN104), 41.5 parts of o-phenylphenoxy ethyl acrylate (M1142), 1.5 parts of photoinitiator 184, 1.5 parts of photoinitiator TPO and 0.5 parts of silicone slip agent BYK333.

[0070] Comparative Example 3 A brightening film adhesive, with a refractive index of 1.536 at 25°C, has a formulation shown in Table 2, comprising the following components by weight: 30 parts of (30) bisphenol A diacrylate (M2300), 5 parts of (10) bisphenol A diacrylate (EM2265), 30 parts of (4) bisphenol A diacrylate (EM2261), 33.5 parts of o-phenylphenoxyethyl acrylate (M1142), 0.5 parts of photoinitiator 184, 0.5 parts of photoinitiator TPO and 0.5 parts of silicone slip agent BYK333.

[0071] Comparative Example 4 A brightening film adhesive has a refractive index of 1.538 at 25°C. The formulation is shown in Table 2 and includes the following components by weight: 15 parts of (30) bisphenol A diacrylate ethoxylate (M2300), 30 parts of (10) bisphenol A diacrylate ethoxylate (EM2265), 10 parts of (4) bisphenol A diacrylate ethoxylate (EM2261), 16.5 parts of bisphenol A epoxy acrylate oligomer (CN104), 25 parts of o-phenylphenoxy ethyl acrylate (M1142), 1.5 parts of photoinitiator 184, 1.5 parts of photoinitiator TPO and 0.5 parts of silicone slip agent BYK333.

[0072] Comparative Example 5 This comparative example provides a brightening film adhesive, which differs from Example 1 only in that it does not contain polypropylene glycol (700) diacrylate (EM2208), that is, the polypropylene glycol (700) diacrylate (EM2208) is replaced in equal amounts with (4) bisphenol A ethoxylate (EM2261). The remaining components and their quantities are the same as in Example 1.

[0073] Comparative Example 6 This comparative example provides a brightening film adhesive, which differs from Example 1 only in that it does not contain (4) bisphenol A diacrylate (EM2261), that is, (4) bisphenol A diacrylate (EM2261) is replaced with polypropylene glycol (700) diacrylate (EM2208) in equal amounts. The remaining components and their quantities are the same as in Example 1.

[0074] Comparative Example 7 This comparative example provides a brightening film adhesive, which differs from Example 1 only in that it does not contain o-phenylphenoxyethyl acrylate (M1142), that is, o-phenylphenoxyethyl acrylate (M1142) is replaced in equal amounts with (4) bisphenol A diacrylate (EM2261). The remaining components and their quantities are the same as in Example 1.

[0075] Table 1. Components and proportions of the brightening film adhesives in Examples 1-10

[0076] Table 2. Components and proportions of the brightening film adhesives in Comparative Examples 1-7

[0077] Test case (1) Sample preparation: Take 1g of the brightening film adhesive to be tested and place it on a PET film that is 100 micrometers thick, 20 cm wide, and 30 cm long. Cover it with a release film that is 36 micrometers thick, 20 cm wide, and 30 cm long. Spread the adhesive evenly with a roller to make a film about 15 cm wide and 20 cm long. Expose the film to UV curing (the release film is exposed to UV light first), and then peel off the release film. UV exposure parameters: UV medium-pressure mercury lamp, UVA (320nm~400nm) light intensity 1000mw / cm 2 Exposure energy: 200mJ / cm 2 ~300mj / cm 2 ; Take 1g of the brightness enhancement film adhesive to be tested and place it on a PET template with a prism structure measuring 20cm wide and 30cm long. Cover it with a 100μm thick, 20cm wide and 30cm long PET film with a primer, and spread the adhesive evenly with a roller to form a film approximately 15cm wide and 15cm long. Irradiate the film with a UV curing machine (the PET film with the primer is irradiated first), and the brightness enhancement film adhesive forms a focusing microprism structure layer. Remove the template to obtain the optical brightness enhancement film. Prism structure parameters: prism angle 90 degrees, peak spacing between two adjacent prism structures in the prism layer 50±1µm; UV exposure parameters: UV medium-pressure mercury lamp, UVA (320nm~400nm) light intensity 1000mw / cm². 2 Exposure energy: 200mJ / cm 2 ~300mj / cm 2 ; (2) Performance testing: (a) Refractive index test: The brightening film adhesive was dropped onto the Abbe refractometer (WAY-2S) to test its refractive index. The test temperature was 25℃. The refractive index is the refractive index of the liquid. The test was conducted under the same test conditions. (b) Water contact angle test: The water contact angle of flat film and prism film was tested according to GB / T 30693-2014 "Measurement of water contact angle of plastic film". (c) Abrasion resistance test: Fix a diffusion film on the table with the diffusion layer facing up. Place the brightness enhancement film to be tested above the diffusion film with the prism structure layer facing down in contact with the diffusion film. Then fix a 200-gram weight above the prism film. Pull the brightness enhancement film back and forth 10 times at a speed of 10cm / s, moving a distance of 10cm. The abrasion resistance of the brightness enhancement film is judged by detecting the degree of scratches on the surface of the brightness enhancement film at the weight position. The numbers 1 to 5 are used to represent the abrasion resistance, where 1 indicates poor abrasion resistance and 5 indicates excellent abrasion resistance. (d) Resilience: The surface of the prism film is lightly scratched with the tip of a 250um thick PET substrate, and the resilience is judged by the time it takes for the scratch to disappear; it is represented by numbers 1 to 5, where 1 indicates poor resilience and 5 indicates excellent resilience. The performance test results are shown in Tables 3 and 4.

[0078] According to the test data in Tables 3 and 4, the water droplet angle of the prism film is smaller than that of the planar adhesive film, indicating that the prism structure makes it easier for water droplets to spread. Data from Examples 1 to 10 show that the water droplet angle of the prism film is greater than 59 degrees, preventing water droplet spread and effectively solving the problem of bright water vapor lines. Examples 2, 5, 6, and 7 exhibit excellent abrasion resistance and QQ resilience, with liquid refractive indices all exceeding 1.515, demonstrating excellent overall performance. Examples 3, 4, and 10 show good abrasion resistance and QQ resilience, although the liquid refractive index of Example 10 is slightly low at 1.505. Examples 1, 8, and 9 show only average abrasion resistance and QQ resilience. Based on the test data from Comparative Examples 1, 2, 3, 4, and 6, water droplets spread along the prism film, producing bright lines, indicating that the formulation is relatively hydrophilic. Comparative Examples 5 and 7 contain low proportions of ethoxy or propionic segments. Although they perform well in improving moisture bright lines, they exhibit poor abrasion resistance and QQ resilience.

[0079] In summary, the brightness enhancement film adhesive of this invention has the following advantages: First, the liquid refractive index of the brightness enhancement film adhesive is ≥1.51, and the high refractive index brings high brightness gain; second, the brightness enhancement film made with the brightness enhancement film adhesive has both excellent elastic recovery and strength, ensuring that no wear occurs during transportation or cutting; third, the brightness enhancement film adhesive has good hydrophobicity, which can prevent water droplets from spreading along the grooves of the brightness enhancement film and avoid the problem of optical bright lines.

[0080] Table 3 Performance test results of the adhesives and the resulting brightening films in Examples 1-10

[0081] Table 4 Performance test results of the adhesives and the resulting brightening films in Comparative Examples 1-7

[0082] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A brightening film adhesive, characterized in that, Includes component A, component B, component C, and component D; Component A is a bifunctional acrylate monomer with elastic recovery properties; Component A includes component A1; The A1 component is selected from acrylate monomers containing propylene oxide segments; Component B is a bifunctional bisphenol A di(meth)acrylate monomer and / or a di(meth)acrylate oligomer of the bisphenol A epoxy resin backbone. Component C is a monofunctional acrylate monomer; Component D is a photoinitiator.

2. The brightening film adhesive according to claim 1, characterized in that, The A1 component is selected from any of the following acrylate monomers: MM-(MON) a -AA,10≤a≤30; MM-(MON) b -R1-(PO) c -AA,10≤b+c≤30; AA-(EO) d -(PO) e -R2-(PO) f -(IS) g -AA,d+g≤10,10≤e+f,d+g+e+f≤30; AA-(PO) e -(IS) d -R3-(EO) g -(PO) f -AA,d+g≤10,10≤e+f,d+g+e+f≤30; R1, R2, and R3 are each independently selected from bisphenol A, bisphenol fluorene, ethylene glycol, propylene glycol, butanediol, pentanediol, hexanediol, nonanediol, decanediol, undecyldiol, dodecyldiol, tridecyldiol, tetradecyldiol, or pentadecyldiol.

3. The brightening film adhesive according to claim 1, characterized in that, Component A further includes component A2; The A2 component is selected from acrylate monomers containing ethoxylated segments; Preferably, component A2 is selected from any one of the following acrylate monomers: AA-(EO) h -AA,5≤h≤10; AA-(EO) i -R4-(EO) j -AA ,5≤i+j≤10; R4 is selected from bisphenol A, bisphenol fluorene, ethylene glycol, propylene glycol, butanediol, pentanediol, hexanediol, nonanediol, decanediol, undecyldiol, dodecyldiol, tridecyldiol, tetradecyldiol, or pentadecyldiol.

4. The brightening film adhesive according to claim 1, characterized in that, Component A further includes component A3; The A3 component is selected from acrylate monomers containing propylene oxide segments; Preferably, component A3 is selected from any one of the following acrylate monomers: MM-(MON) k -AA,5≤k≤10; MM-(MON) m -R5-(PO) n -AA,5≤m+n≤10; R5 is selected from bisphenol A, bisphenol fluorene, ethylene glycol, propylene glycol, butanediol, pentanediol, hexanediol, nonanediol, decanediol, undecyldiol, dodecyldiol, tridecyldiol, tetradecyldiol, or pentadecyldiol.

5. The brightening film adhesive according to any one of claims 1-4, characterized in that, The bisphenol A di(meth)acrylate monomer includes at least one of BPA(2EO)DA, BPA(3EO)DA, BPA(4EO)DA, BPA(2EO)DMA, BPA(3EO)DMA and BPA(4EO)DMA; Preferably, the di(meth)acrylate oligomer of the bisphenol A epoxy resin backbone includes at least one of bisphenol A di(meth)acrylate oligomer and bisphenol A di(meth)acrylate oligomer modified with flexible segments; Preferably, the monofunctional acrylate monomer includes at least one of dibenzofuran methacrylate, biphenyl methacrylate, o-phenylphenoxyethyl acrylate, o-phenylphenoxyethyl ethoxy acrylate, phenoxyphenyl methacrylate, phenoxyethyl acrylate, and benzyl acrylate. Preferably, the photoinitiator includes at least one of photoinitiator 1173, photoinitiator 184, photoinitiator MBF, photoinitiator TPO, photoinitiator TPO-L, and photoinitiator BAPO.

6. The brightening film adhesive according to claim 5, characterized in that, The brightening film adhesive also includes component E; Component E is an auxiliary agent; Preferably, the additives include at least one of ultraviolet absorbers, antistatic agents, defoamers, and slip agents.

7. The brightening film adhesive according to claim 6, characterized in that, The brightening film adhesive comprises the following components in 100 parts by total weight: Component A: 25-45 parts, Component B: 10-30 parts, Component C: 25-50 parts, Component D: 1-5 parts, and Component E: less than 1 part.

8. A method for preparing the brightening film adhesive according to any one of claims 1-7, characterized in that, Includes the following steps: The components are mixed to obtain the brightening film adhesive.

9. A brightness enhancement film, characterized in that, It is formed by UV curing of the brightening film adhesive as described in any one of claims 1-7.

10. The application of the brightness enhancement film according to claim 9 in a liquid crystal display.

Images