An edge coated film

Abstract

The present invention discloses an edge co-coated film, which includes an optical functional layer. The optical functional layer at least contains a resin coating film formed by coating an optical compensation film resin coating solution. An edge film formed by coating an elastic resin coating solution is provided at the edge along the conveying direction of the optical functional layer. A splicing area formed by laminating the resin coating film and the edge film is formed on the optical functional layer. The width of the splicing area perpendicular to the conveying direction of the optical functional layer is 0.9 to 1.1 cm. Since the edge co-coated film of the present invention has a co-coated area formed by coating the optical compensation film resin coating solution and the elastic resin coating solution, that is, a splicing area formed by overlapping the two coatings, when cutting the edge before stretching, only part of the dry film of the elastic resin coating solution is cut off, and no incision will be formed during edge cutting, and the film will not be broken during stretching, which is beneficial to the batch production of the film.

Description

Technical Field

[0001] The present invention is an edge coated film, specifically an edge coated film used for preparing an optical compensation film, belonging to the technical field of optical film preparation. Background Art

[0002] Optical compensation films are usually produced by extrusion. After injecting resin into an extruder and heating it to melt, it is discharged from a T-shaped die head, passed through a casting roll, and then subjected to stretching in the length and width directions to obtain a biaxially stretched film. Due to the disadvantages of high equipment cost and complex process in the extrusion method, and it is not easy to remove the bubble defects in the extrusion. In recent years, a method of producing optical compensation films by coating has emerged. Specifically, a resin coating solution is made by dissolving polymer resin powder or particles in an organic solvent, and then the resin coating solution is uniformly coated on a support by a slit coating method. After baking and peeling the support, a resin film is obtained, and then the resin film is biaxially stretched to obtain an optical compensation film. However, during the slit coating process, the edges of the resin film often have uneven thickness and uneven edge closing. Therefore, trimming is required before stretching. However, due to the relatively large brittleness of the resin film, cuts are easily formed during the trimming process, which then leads to film breakage during stretching, affecting the finished product quality of the optical compensation film.

[0003] In the prior art, the invention patent with the publication number CN106415340A discloses that when manufacturing a retardation film, first a resin solution is coated on a support film, then the resin solution is dried by heating to form a laminate in which a coating film is closely laminated on the support film. Then, the laminate is stretched in at least one direction in the stretching process, and optical anisotropy is imparted to the coating film. Finally, the support is peeled off from the stretched laminate to obtain the retardation film. The coating methods used in the above method are not limited to various methods such as knife roll coating, roll licking coating, gravure coating, reverse coating, spray coating, wire bar coating, etc. By adding additives such as leveling agents and anti-degradation agents to the coating, setting the film forming thickness, controlling the drying and heating temperature, etc., the appearance performance of the film can be improved. Although stretching can be carried out without trimming, there are still problems of large operation difficulty and poor stability.

[0004] The invention patent with the publication number TW202237377A discloses a manufacturing method of an obliquely stretched film. This method can solve the problem that the film will not break during and after the trimming process. Specifically, during the oblique stretching process of the film, by using a pair of holding tools to hold both ends in the width direction of the film, one of the holding tools is relatively moved forward and the other holding tool is relatively delayed to move to transport the film, and the film is stretched in the width direction towards the inclined direction. This method is to trim the film after oblique stretching to make it have excellent quality of the cut surface of the film.

[0005] As can be seen from the above, in the process of preparing the optical film, in order to improve the appearance performance of the resin film after coating and solve the problem of easy cracking during trimming, usually the film-making process before trimming (including coating, drying or stretching, etc.) is adjusted. However, these methods often put higher requirements on the precise control of the process, making the film production more difficult and the product quality less stable. Therefore, in order to solve the trimming problem of the film in the current slit coating method, it is of great significance to provide a film that has no notch after trimming and can meet the optical performance requirements of the product after subsequent stretching on the premise of meeting the high-efficiency and high-quality production of film industrialization. Summary of the Invention

[0006] The object of the present invention is to provide an edge co-coated film. The film has a co-coated area formed by coating an optical compensation film resin coating solution and an elastic resin coating solution, that is, a splicing area formed by overlapping coating of the two. When trimming before stretching, only the dry film of part of the elastic resin coating solution is cut off, and no notch will be formed during trimming, and the film will not break during stretching, which is beneficial to the batch production of the film.

[0007] The present invention is realized through the following technical solutions: An edge co-coated film includes an optical functional layer. The optical functional layer at least contains a resin coating film formed by coating an optical compensation film resin coating solution. Along the edge of the optical functional layer in the conveying direction, there is an edge film formed by coating an elastic resin coating solution, and a splicing area formed by laminating the resin coating film and the edge film is formed on the optical functional layer. The width of the splicing area perpendicular to the conveying direction of the optical functional layer is 0.9 - 1.1 cm.

[0008] The film thickness of the co-coated area on the edge co-coated film is 20 - 50 μm.

[0009] The edge co-coated film is formed by heating. The heating includes pre-baking and calcination after pre-baking. The temperature of the pre-baking is set to 50 - 100 °C, and the time is 15 s - 10 min; the calcination temperature is set to 100 - 200 °C, and the time is 5 - 200 min.

[0010] The raw materials of the elastic resin coating solution at least contain an optical compensation film resin coating solution and organic elastic particles.

[0011] The organic elastic particles account for 1 - 5 w / w% of the elastic resin coating solution.

[0012] The solid content of the organic elastic resin coating solution is 10 - 20%.

[0013] The organic elastic particles include one or more of ultra-high molecular weight polyethylene particles, polypropylene particles, polyimide resin particles, acrylonitrile-butadiene-styrene copolymer resin particles, polyester resin particles with 8 or more carbon atoms.

[0014] The resin coating solution for the optical compensation film contains at least a resin for the compensation film, a leveling agent, and an organic solvent.

[0015] The resin for the compensation film includes one or more of (meth)acrylic resins, polycarbonate resins, cycloolefin resins, cellulose resins, polyester resins, polyester carbonate resins, polyvinyl acetal resins, olefin resins, and polyurethane resins.

[0016] The coating methods for the resin coating solution for the optical compensation film or the elastic resin coating solution include slot coating, roll coating, knife coating, reverse coating, gravure coating, spray coating, air knife coating, or wire bar coating.

[0017] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0018] (1) The present invention is a side co-coated film proposed to solve the problems that the optical resin film is prone to form incisions during trimming and is prone to film breakage during stretching after trimming. Its essence is to coat an elastic resin coating solution again on the side of the support body with a resin coating film, so that the elastic resin coating solution layer covers the side of the resin coating film, and the co-coated area of the two forms a splicing area. When the side co-coated film prepared in this way is trimmed, only part of the elastic resin coating solution layer is cut off, and no incision will be formed during trimming. After trimming, the film will not break during the stretching process, which will affect the optical properties of the film, and the quality of the finished product can be guaranteed.

[0019] (2) When trimming the film in the present invention, since only the side film formed by coating part of the elastic resin coating solution is cut off and part of the co-coated area is retained, by limiting the width of the co-coated area, it is convenient for seamless connection between the resin coating film and the side film, which is beneficial to subsequent peeling and stretching processes.

[0020] (3) The present invention can realize continuous coating of the optical functional coating solution and the elastic resin coating solution during the transportation of the support body. The coating method can adopt known devices such as slot coating and roll coating. The coating device for the elastic resin coating solution can be set at the downstream position of the optical functional coating solution coating device, and only need to be improved on the existing device, with a simple structure and low cost.

[0021] (4) When preparing the side co-coated film in the present invention, only by adjusting or controlling the coating device, the side co-coated layer with the required thickness or coating width, that is, the coating structure formed in the co-coated area, can be obtained. There are no restrictions on the stretching process and drying process in the film preparation process, and the original process can be operated, which is simple and easy to control.

[0022] In summary, the present invention provides an edge co-coated film that can be prepared by continuous coating, which can be used to solve the problems of easy occurrence of cut edges and film breakage during stretching when cutting optical films. Since the preparation process is simple, only by adding an edge coating device at an appropriate position on the original production line, the equipment investment cost can be greatly reduced, mass production of products can be achieved, and the product yield is high. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic structural diagram of the edge co-coated film of the present invention.

[0024] Figure 2 It is a top view of the coating device of the present invention.

[0025] Figure 3 It is a schematic structural diagram of the slot coating die head of the present invention.

[0026] Figure 4 It is a photo of the cut edge of the film after trimming.

[0027] Among them, A is the width of the optical functional layer, B is the width of the edge film, and C is the width of the splicing area;

[0028] 1 - Support body, 2 - Slot coating die head, 3 - Edge coating die head, 4 - Front clamp block, 5 - Rear clamp block, 6 - Spacer gasket, 7 - Storage bin, 8 - Feed inlet, 9 - Lip. DETAILED DESCRIPTION OF THE INVENTION

[0029] The object of the invention, technical solutions and beneficial effects of the present invention will be further described in detail below.

[0030] It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the claimed invention. Unless otherwise noted, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field to which the present invention belongs.

[0031] Structure of the edge co-coated film:

[0032] As Figure 1 shown, it has an optical functional layer, an edge film, and a splicing area formed by laminating the edge film and the optical functional layer. Among them, the optical functional layer at least contains a resin coating film formed by coating an optical compensation film resin coating solution, and can be formed by coating an optical functional coating solution on the support body 1. Specifically, the optical functional coating solution can include an optical compensation film resin coating solution or a resin coating solution of other optical performance films. When multiple resin coating solutions are used for coating, they can be coated separately to form a laminate with corresponding optical properties on the support body 1. It is also possible to use only the optical compensation film resin coating solution as the optical functional coating solution in a specific implementation process and coat it on the support body 1 by a slot coating device.

[0033] Further, the resin coating liquid for the optical compensation film is obtained by fully dissolving a certain amount of the resin for the compensation film in an organic solvent, and a fluorine-based or polysiloxane-based leveling agent may also be added thereto.

[0034] Specifically, the resin for the optical compensation film can be made of any suitable material as long as it can meet the environment in which it is used. As specific examples, the following can be cited: (meth)acrylic resins, polycarbonate resins, cycloolefin resins, cellulose resins, polyester resins, polyester carbonate resins, polyvinyl acetal resins, olefin resins, polyurethane resins, etc.

[0035] As specific examples of the (meth)acrylic resins, polymethyl methacrylate, poly(meth)acrylate, methyl methacrylate-(meth)acrylic acid copolymer, methyl methacrylate-(meth)acrylate copolymer, methyl methacrylate-acrylate-(meth)acrylic acid copolymer, (meth)acrylate-styrene copolymer (MS resin), etc. can be cited. As a preference, it can be exemplified that the number of carbon atoms of acrylic acid in methyl methacrylate is 4 to 8.

[0036] As the above-mentioned cycloolefin resin, it can be exemplified as being prepared by ring-opening polymerization of a norbornene monomer and a copolymerizable monomer followed by hydrogenation. Among them, specific examples of the norbornene monomer can be: bicyclo[2.2.1]hept-2-ene, tricyclo[4,3,0,12,5]-3-decene, tricyclo[4,4,0,12,5]-3-undecene, 7-methyltricyclo[4,4,0,12,5]-3-undecene, 5-methylbicyclo[2,2,1]hept-2-ene, 1-methylbicyclo[2,2,1]hept-2-ene, 7-methylbicyclo[2,2,1]hept-2-ene, 5-ethylbicyclo[2,2,1]hept-2-ene, etc. One or more of these monomers and the copolymerizable monomer can be cyclobutene, cyclopentene, cyclooctene, dicyclopentadiene, etc.

[0037] As the above-mentioned polycarbonate resin, any suitable polycarbonate resin can be used. For example, a polycarbonate resin containing a structural unit derived from a dihydroxy compound is preferably used. Specific examples of the dihydroxy compound include: 9,9-bis(4-hydroxyphenyl)fluorene, bisphenol fluorene, 9,9-bis(4-hydroxy-3-methylphenyl)fluorene, 9,9-bis(4-hydroxy-3-ethylphenyl)fluorene, 9,9-bis(4-hydroxy-3-n-propylphenyl)fluorene, 9,9-bis(4-hydroxy-3-isopropylphenyl)fluorene, 9,9-bis(4-hydroxy-3-n-butylphenyl)fluorene, 9,9-bis(4-hydroxy-3-sec-butylphenyl)fluorene, etc. In addition to containing a structural unit derived from the above-mentioned dihydroxy compound, the polycarbonate resin may also contain a structural unit derived from a dihydroxy compound such as isosorbide, isoditromannitol, isoidide, spirodiol, dioxanediol, diethylene glycol, triethylene glycol, polyethylene glycol, bisphenol, etc.

[0038] Specifically, the organic solvents for dissolving the above-mentioned optical compensation film resin coating solution include: N-methyl-2-pyrrolidone, γ-butyrolactone, γ-butyrolactam, N,N-dimethylformamide, N,N-dimethylacetamide, 4-hydroxy-4-methyl-2-pentanone, ethylene glycol monomethyl ether, butyl lactate, butyl acetate, methyl methoxypropionate, ethyl ethoxypropionate, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol-n-propyl ether, ethylene glycol-isopropyl ether, ethylene glycol-n-butyl ether (butyl cellosolve), ethylene glycol dimethyl ether, ethylene glycol ethyl ether acetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diisobutyl ketone, isopentyl propionate, isopentyl isobutyrate, diisopentyl ether, ethylene carbonate, propylene carbonate, etc. These organic solvents can be used alone or in combination of two or more. Based on 100 parts by weight of the resin component, the amount of the organic solvent is 400 to 1000 parts by weight, more preferably 500 to 600 parts by weight. When the organic solvent exceeds 1000 parts, the mechanical strength of the formed compensation film becomes low. When the amount of the organic solvent is less than 400 parts, the viscosity of the compensation film coating solution is too high and the film-forming performance becomes poor.

[0039] In the present invention, the use of a leveling agent can effectively prevent oxygen from hindering the curing of the coating film surface during coating and drying of the optical compensation film resin coating solution, and can impart the effect of scratch resistance to the coating film surface. Based on 100 parts by weight of the resin component, the content of the leveling agent is preferably 0.005 to 20 parts by weight, more preferably 0.01 to 10 parts by weight, and further preferably 0.01 to 3 parts by weight. It should be noted that two or more leveling agents can be used in combination.

[0040] The edge film is formed by coating an elastic resin coating solution on the edge of the support 1 along the conveyance direction of the optical functional layer. A splicing area can be formed on the optical functional layer, and then heated to obtain a dry film. After peeling off the support 1, the edge co-coated film is obtained. The width of the splicing area perpendicular to the conveyance direction of the optical functional layer is 0.9 - 1.1 cm, which can enable only a part of the edge film to be cut off when the edge co-coated film is trimmed. The splicing area on the edge co-coated film can avoid the occurrence of incisions during trimming, which may cause the film to be easily broken after stretching, and can improve and ensure the product quality of the optical film.

[0041] Specifically, the elastic resin coating solution contains at least the above-mentioned optical compensation film resin coating solution and organic elastic particles. The optical compensation film resin coating solution can correspond to the optical compensation film resin coating solution coated on the support 1; the use of organic elastic particles is to improve the elasticity and toughness of the edge film formed by edge coating. 1 - 5 w / w% of the amount of the elastic resin coating solution can be added to the elastic resin coating solution. Specific examples of the organic elastic particles can include plastic beads, specifically, one or more of ultra-high molecular weight polyethylene particles, polypropylene particles, polyimide resin particles, acrylonitrile-butadiene-styrene copolymer resin particles, and polyester resin particles with 8 or more carbon atoms. When preparing the elastic resin coating solution, the same optical compensation film resin and organic elastic particles are fully dissolved in the corresponding organic solvent, and the solid content of the prepared elastic resin coating solution is 10 - 20%.

[0042] The support 1 used for the edge co-coated film is a flexible substrate, and usually a transparent substrate of synthetic resin such as polyethylene terephthalate (PET), triacetyl cellulose (TAC), polyethersulfone, polyamide, polyimide, polymethyl methacrylate, and polycarbonate can be used. Considering cost factors, polyethylene terephthalate is preferably used.

[0043] Preparation process of the edge co-coated film:

[0044] It mainly includes the coating of the optical functional layer, the coating of the edge film, and the heat forming of the film.

[0045] In a specific embodiment, when only the optical compensation film resin coating solution is used for the optical functional layer, a slot coating device can be used to coat it on the support 1, and then an elastic resin coating solution is coated on the edge in the conveyance direction of the support 1, so that the elastic resin coating solution and the optical functional coating solution form a co-coated area on the support 1, and then heated to obtain a dry film. After peeling off the support 1, the edge co-coated film is obtained.

[0046] Among them, in addition to the slot coating method, the optical compensation film resin coating solution and the elastic resin coating solution can also be coated by methods such as roll coating, knife coating, reverse coating, gravure coating, spray coating, air knife coating or wire bar coating.

[0047] Specifically, when using slot coating, first, the optical compensation film resin coating solution is injected into the slot coating cavity and coated on the support 1 through the slot coating die head 2 to form a wet compensation film. And a side coating die head 3 is arranged downstream in the conveying direction of the support 1, so that the side coating die head 3 is about 10-15 cm away from the slot coating die head. The side coating die head 3 can select a suitable coating method according to the requirements of the production line, as long as it can coat the elastic resin coating solution on the edge of the wet compensation film. It should be noted that this edge refers to the edge in the conveying direction of the wet compensation film.

[0048] After side co - coating, the width of the co - coating area of the elastic resin coating solution and the wet compensation film is 0.9 - 1.1 cm, as shown in Figure 1 the shaded part. The wet film thickness of the coating can be adjusted by adjusting the settings of the slot coating die head 2 or the side coating die head 3.

[0049] The heating temperature of the film is appropriately selected according to the type of organic solvent used. Preferably, two stages of pre - baking and calcination are implemented. The pre - baking temperature is set at 50 - 100 °C and the time is 15 s - 10 min; the calcination temperature is set at 100 - 200 °C and the time is 5 - 200 min.

[0050] In a specific embodiment, the pre - baking temperature can be set at 60 - 80 °C and the time is 30 s - 50 min; the calcination temperature is set at 120 - 150 °C and the time is 10 - 100 min. When the organic solvent in the coated film volatilizes to an organic solvent content of less than 2%, the film is cooled, and the cooling temperature is controlled at 60 - 100 °C. The film thickness of the obtained dry film is 0.001 - 1 μm, or further controlled at 0.005 - 0.5 μm.

[0051] The following takes several typical embodiments to illustrate the specific implementation manners of the present invention. Of course, the protection scope of the present invention is not limited to the following embodiments.

[0052] Example 1:

[0053] From the above - mentioned side co - coating process, it can be seen that two groups of coating die heads are respectively used for coating on the support 1. The coating die head can select a suitable coating method according to the coating requirements or the requirements of the resin coating solution. For example, the slot coating method selected in this embodiment is specifically shown in Figure 2As shown in the figure, a slot coating die head 2 is arranged above the conveying path of the support body 1 to coat the optical compensation film resin coating liquid on the support body 1 during the conveying process of the support body 1. An edge coating die head 3 is arranged 15 cm away from the slot coating die head. Also adopting the slot coating method, during the moving process of the support body 1, the elastic resin coating liquid is coated on the edge of the support body 1. The coating area of the elastic resin coating liquid and the optical functional coating liquid forms a splicing area, as Figure 1 shown in the shaded part

[0054] Specifically, the structures of the slot coating die head 2 and the edge coating die head 3 adopted in this embodiment are as Figure 3 shown, including a front clamping block 4, a rear clamping block 5 and a gap gasket 6. A storage bin 7 and a feed inlet 8 connecting the storage bin 7 are arranged on the rear clamping block 5. The front clamping block 4 and the rear clamping block 5 are fixed by a matching positioning bolt assembly. The gap gasket 6 is fixed between the front clamping block 4 and the rear clamping block 5 and is provided with a flow channel. One end of the flow channel is connected to the storage bin 7, and the other end is connected to a lip 9 formed by the fixation of the front clamping block 4 and the rear clamping block 5. The function of the storage bin 7 is to make the coating liquid have the function of adjusting the pressure uniformity of the lip 9 and slowing down the pressure fluctuation during the conveying process before the coating liquid is extruded from the lip 9. The feed inlet 8 is used to connect the feed pipe, and different connection methods can be designed according to the specific production line requirements, with strong practicability

[0055] Example 2:

[0056] Using a PET film as the support body 1, adopting the coating device of Example 1, after coating the optical compensation film resin coating liquid on the PET film, then coating the elastic resin coating liquid on the PET film. Adjust the position of the lip 9 of the slot coating die head and the edge coating die head 3 to form a coating area between the elastic resin coating liquid and the optical functional coating liquid. Then pre-bake the coated PET film at a temperature of 50 - 100 °C for 15 s - 10 min, and then calcine it at a temperature of 100 - 200 °C for 5 - 200 min. After the dry film is prepared and cooled, the PET film is peeled off to obtain the edge co-coated thin film

[0057] Specifically, the optical compensation film resin coating liquid adopted in this embodiment is prepared by adding 100 parts of polymethyl methacrylate PMMA to 800 parts of N-methyl-2-pyrrolidone, stirring at high speed and fully dissolving, and then adding 5 parts of fluorine-based leveling agent. The elastic resin coating liquid is a coating liquid with a solid content of 20% prepared by adopting the optical compensation film resin coating liquid with the same composition and adding 3.5 w / w% of polyimide resin particles

[0058] Further, control the conveyance speed of the PET film at 5 m / min. On the slot coating die head, control the thickness (shim) of the spacer 6 at 250 um, the gap (GAP) at the flow port at 80 um, the pump speed at 2500 rpm, and the chamber pressure at 0.20 MPa. On the edge coating die head 3, control the thickness (shim) of the spacer 6 at 200 um, the gap (GAP) at the flow port at 50 um, the pump speed at 250 rpm, and the chamber pressure at 0.20 MPa.

[0059] The edge co-coated film thus obtained satisfies: the thickness of the optical compensation film is 45 um, the film thickness of the co-coated area is 50 um, and the width of the co-coated area is set at 1.1 cm.

[0060] Example 3:

[0061] The difference between this example and Example 2 lies only in the selection of the resin coating solution and the control parameters of the coating die head.

[0062] Specifically, in this example, the optical compensation film resin coating solution used is prepared by adding 100 parts of polymethyl methacrylate PMMA to 550 parts of N, N-dimethylformamide, stirring at high speed and dissolving thoroughly, and then adding 3 parts of a polysiloxane leveling agent. The elastic resin coating solution is a coating solution with a solid content of 14% prepared by using the optical compensation film resin coating solution with the same composition and adding 1.0 w / w% of polyimide resin particles.

[0063] Further, control the conveyance speed of the PET film at 5 m / min. On the slot coating die head, control the thickness (shim) of the spacer 6 at 300 um, the gap (GAP) at the flow port at 100 um, the pump speed at 3000 rpm, and the chamber pressure at 0.25 MPa. On the edge coating die head 3, control the thickness (shim) of the spacer 6 at 100 um, the gap (GAP) at the flow port at 50 um, the pump speed at 200 rpm, and the chamber pressure at 0.15 MPa.

[0064] The edge co-coated film thus obtained satisfies: the thickness of the optical compensation film is 40 um, the film thickness of the co-coated area is 47 um, and the width of the co-coated area is set at 0.9 cm.

[0065] Example 4:

[0066] The difference between this example and Example 2 lies only in the selection of the resin coating solution and the control parameters of the coating die head.

[0067] Specifically, in this embodiment, the optical compensation film resin coating solution is prepared by adding 100 parts of polymethyl methacrylate (PMMA) to 600 parts of N,N-dimethylacetamide, stirring at high speed and dissolving fully, and then adding 3 parts of fluorine-based leveling agent. The elastic resin coating solution is a coating solution with a solid content of 17% prepared by using the optical compensation film resin coating solution with the same composition and adding 2.5 w / w% of polyethylene particles.

[0068] Furthermore, in this embodiment, the conveyance speed of the PET film is controlled at 5 m / min. On the slot die coater, the thickness (shim) of the gap spacer 6 is 300 μm, the gap (GAP) at the flow port is 60 μm, the pump speed is 3000 rpm, and the chamber pressure is 0.25 MPa. On the edge coater die 3, the thickness (shim) of the gap spacer 6 is 180 μm, the gap (GAP) at the flow port is 60 μm, the pump speed is 300 rpm, and the chamber pressure is 0.25 MPa.

[0069] The edge co-coated film thus obtained satisfies the following: the thickness of the optical compensation film is 39 μm, the film thickness in the co-coated area is 45 μm, and the width of the co-coated area is set to 1.0 cm.

[0070] Example 5:

[0071] The difference between this embodiment and Example 2 lies only in the selection of the resin coating solution and the control parameters of the coating die.

[0072] Specifically, in this embodiment, the optical compensation film resin coating solution is prepared by adding 100 parts of polymethyl methacrylate (PMMA) to 500 parts of N-methyl-2-pyrrolidone, stirring at high speed and dissolving fully, and then adding 0.5 part of polysiloxane-based leveling agent. The elastic resin coating solution is a coating solution with a solid content of 18.8% prepared by using the optical compensation film resin coating solution with the same composition and adding 3.0 w / w% of acrylonitrile-butadiene-styrene copolymer resin particles.

[0073] Furthermore, in this embodiment, the conveyance speed of the PET film is controlled at 5 m / min. On the slot die coater, the thickness (shim) of the gap spacer 6 is 220 μm, the gap (GAP) at the flow port is 70 μm, the pump speed is 2500 rpm, and the chamber pressure is 0.20 MPa. On the edge coater die 3, the thickness (shim) of the gap spacer 6 is 100 μm, the gap (GAP) at the flow port is 70 μm, the pump speed is 300 rpm, and the chamber pressure is 0.20 MPa.

[0074] The edge co-coated film thus obtained satisfies the following: the thickness of the optical compensation film is 32 μm, the film thickness in the co-coated area is 36 μm, and the width of the co-coated area is set to 0.9 cm.

[0075] Example 6:

[0076] The only difference between this embodiment and embodiment 2 is the selection of the resin coating liquid and the control parameters of the coating die head.

[0077] Specifically, in this embodiment, the optical compensation film resin coating liquid was prepared by adding 100 parts of polymethyl methacrylate (PMMA) to 600 parts of N-methyl-2-pyrrolidone, stirring at high speed until fully dissolved, and then adding 2 parts of a fluorine-based leveling agent. The elastic resin coating liquid was prepared by using the same composition of the optical compensation film resin coating liquid, adding 5 w / w% of polypropylene particles to obtain a coating liquid with a solid content of 23%.

[0078] Furthermore, in this embodiment, the PET film conveying speed was controlled to 5 m / min. On the slot coating die, the gap shim 6 thickness (shim) was controlled to 240 μm, the runner gap (GAP) was controlled to 90 μm, the pump speed was controlled to 2650 rpm, and the chamber pressure was controlled to 0.23 MPa. On the edge coating die 3, the gap shim 6 thickness (shim) was controlled to 200 μm, the runner gap (GAP) was controlled to 65 μm, the pump speed was controlled to 225 rpm, and the chamber pressure was controlled to 0.18 MPa.

[0079] The edge co-coated film thus prepared meets the following requirements: the thickness of the optical compensation film is 36 μm, the film thickness of the co-coated area is 44 μm, and the width of the co-coated area is set to 1.0 cm.

[0080] Comparative Example 1:

[0081] The difference between this comparative example and Example 2 is only that different resin coating liquids are used in edge co-coating.

[0082] Specifically, in this comparative example, organic elastic particles are not added to the resin coating liquid for edge co-coating, and only optical compensation resin coating liquid of the same component is used. The conveying speed of the PET film, the coating device, the control parameters of the slit coating die 2, the pre-drying and calcination conditions involved in the process are all the same, but the control parameters of the edge coating die 3 are slightly different.

[0083] That is, the thickness (shim) of the gap gasket 6 on the edge coating die 3 is controlled to be 95 μm, the flow channel gap (GAP) is controlled to be 55 μm, the pump speed is controlled to be 200 rpm, and the cavity pressure is controlled to be 0.18 MPa.

[0084] The film thus prepared meets the following requirements: the thickness of the optical compensation film is 40 μm, the thickness of the co-coating area is 62 μm, and the width of the co-coating area is set to 0.93 cm.

[0085] Comparative Example 2:

[0086] In this comparative example, the optical compensation film resin coating solution was directly coated on a PET film by a slot coating method, and then dried by heating to obtain a dry film. After peeling off the support 1, the obtained optical film was obtained.

[0087] The conveying speed of the PET film, the slot coating die head 2, the control parameters of the slot coating die head 2, the pre-drying and calcination conditions involved in the coating process of this comparative example were the same as those in Example 2.

[0088] The film thus obtained satisfied that the thickness of the optical compensation film was 40 μm.

[0089] The optical films of the above-mentioned Examples 2 to 6, Comparative Example 1 and Comparative Example 2 were trimmed (that is, during the process of peeling off the support 1, a cutter was used to trim the edges of the film), and generally about 2 cm of the edge part needed to be cut off.

[0090] The cut edges of the above-mentioned optical films after trimming were observed respectively. Visible to the naked eye, the edges of the films in Examples 2 to 6 were smooth and neat, while there were many small notches in the edges of the films in Comparative Example 1 and Comparative Example 2. For details, see Figure 4 as shown.

[0091] The trimmed films (Examples 2 and 6, Comparative Example 1 and Comparative Example 2) were continuously sent to the stretching process, and the same stretching control process was adopted (such as the stretching temperature was 110 - 140 °C, and the stretching ratio was 1.5 * 1.8 TD * MD) to prepare the optical compensation film. The films in Comparative Example 1 and Comparative Example 2 were broken during the stretching process and could not be effectively formed into films. The optical properties of the optical compensation films prepared in Examples 2 to 6 were detected, and the detection results are shown in Table 1 below.

[0092] Table 1 Data table of optical property detection

[0093]

[0094] Using the method of Example 2 to produce the optical compensation film, 10 batches (the output of each batch of optical compensation film was 1500 square meters) of optical compensation films were sampled and detected, as shown in Table 2 below. It was judged whether the product performance met the requirements that the solvent residue ≤ 4%, the transmittance > 92%, and the haze < 1%.

[0095] Table 2 Data table of optical property detection of each batch of optical films

[0096]

[0097] The above are only the preferred embodiments of the present invention, and do not impose any form of limitation on the present invention. Any simple modification and equivalent change made to the above embodiments based on the technical essence of the present invention all fall within the protection scope of the present invention.

Claims

1. An edge co-coated film, characterized in that: It includes an optical functional layer. The optical functional layer at least contains a resin coating film formed by coating an optical compensation film resin coating solution. The edge portion along the conveying direction of the optical functional layer has an edge film formed by coating an elastic resin coating solution, and a splicing area formed by laminating the resin coating film and the edge film is formed on the optical functional layer. The width of the splicing area perpendicular to the conveying direction of the optical functional layer is 0.9 - 1.1 cm, and the film thickness of the co - coated area on the edge co - coated film is 20 - 50 μm.

2. The edge-coated film according to claim 1, characterized in that: The edge co - coated film is formed by heating. The heating includes pre - baking and calcination after pre - baking. The temperature of pre - baking is set to 50 - 100 °C, and the time is 15 s - 10 min; the calcination temperature is set to 100 - 200 °C, and the time is 5 - 200 min.

3. The edge-coating film according to claim 1, wherein: The raw materials of the elastic resin coating solution at least contain an optical compensation film resin coating solution and organic elastic particles.

4. The edge-coated film according to claim 3, characterized in that: The organic elastic particles account for 1 - 5 w / w% of the elastic resin coating solution.

5. The edge-coated film according to claim 3, characterized in that: The solid content of the elastic resin coating solution is 10 - 20%.

6. The edge-coated film according to claim 3, characterized in that: The organic elastic particles include one or more of ultra - high molecular weight polyethylene particles, polypropylene particles, polyimide resin particles, acrylonitrile - butadiene - styrene copolymer resin particles, polyester resin particles with 8 or more carbon atoms.

7. The edge-coated film according to any one of claims 1 or 3, characterized in that: The optical compensation film resin coating solution at least contains a resin for compensation film, a leveling agent and an organic solvent.

8. The edge-coating film according to claim 7, characterized in that: The resin for compensation film includes one or more of (meth)acrylic resin, polycarbonate resin, cycloolefin resin, cellulose resin, polyester resin, polyester carbonate resin, polyvinyl acetal resin, olefin resin, polyurethane resin.

9. The edge-coated film according to claim 1, wherein: The coating methods of the optical compensation film resin coating solution or the elastic resin coating solution include slot coating, roll coating, knife coating, reverse coating, gravure coating, spray coating, air knife coating or wire bar coating.

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