An optical reflection composite film and a preparation method thereof

Abstract

The present invention discloses an optical reflection composite film, which is successively composed of a transparent base film, a hot melt adhesive layer, a reflective film, and a reflective coating. The present invention also discloses a preparation method of the above-mentioned optical reflection composite film, which is obtained by laminating a hot melt adhesive layer on the surface of the transparent base film, coating a reflective coating on the surface of the reflective film, and then performing hot pressing and lamination. The optical reflection composite film and its preparation method of the present invention can not only improve production efficiency and reduce costs, but also ensure good reflection effects, and the production process has a significant green environmental protection effect, and is applicable to the reflective film in the OLED lighting field.

Description

Technical Field

[0001] The present invention relates to the technical field of optical thin films, and particularly to an optical reflective composite film and a preparation method thereof. Background Art

[0002] OLED lamps are illuminated by several OLEDs as light sources. The role of reflection is to efficiently reflect the light emitted by the light sources into the illuminated space, reduce light loss, improve illumination brightness, and reduce power consumption. How to improve the reflectivity to make the most of the light emitted by the light sources and maintain a low cost is an important issue to be solved in this field currently. Summary of the Invention

[0003] Based on the technical problems existing in the background art, the present invention proposes an optical reflective composite film and a preparation method thereof.

[0004] An optical reflective composite film proposed by the present invention is successively composed of a transparent base film, a hot melt adhesive layer, a reflective coating, and a reflective film;

[0005] The reflective coating includes the following components in mass percentage: 60%-65% of metal oxide, 5%-10% of glass micro powder, and the balance is silane-modified polyolefin; the metal oxide is zinc oxide, titanium dioxide or a combination thereof.

[0006] The reflective coating is formed by coating a coating solution on one surface of the reflective film and drying. The coating solution includes the following raw materials: polyolefin, alkenyl-containing silane monomer, initiator, metal oxide, glass micro powder, and solvent; the mass ratio of the polyolefin, alkenyl-containing silane monomer to the initiator is (10-20):(2.5-7):(0.3-3).

[0007] Preferably, the polyolefin is at least one of polypropylene homopolymer resin, atactic polypropylene, chlorinated modified polypropylene, and propylene-ethylene copolymer, and the alkenyl-containing silane monomer is at least one of vinyltrimethoxysilane, vinyltris(2-methoxyethoxy)silane, vinyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltriethoxysilane, and 3-methacryloxypropylmethyldiethoxysilane; the initiator is at least one of azobisisobutyronitrile, azobisisoheptonitrile, benzoyl peroxide, and lauroyl peroxide.

[0008] Among them, under the action of the initiator, the polyolefin and the alkenyl-containing silane monomer in the coating solution are bonded by chemical bonds to form silane-modified polyolefin.

[0009] Preferably, the solid content of the coating solution is 2.5-5.0 wt%, and the coating amount is 7-10 g / m2 .

[0010] Preferably, the solvent is at least one of ethyl acetate, butyl acetate, acetone, and ethanol.

[0011] Preferably, the mass ratio of zinc oxide to titanium dioxide is (2 - 3):1.

[0012] Preferably, the transparent base film is a biaxially oriented polypropylene film or a biaxially oriented polyethylene terephthalate film.

[0013] Preferably, the raw material of the hot melt adhesive layer is at least one of EVA, EAA, and EMA.

[0014] Preferably, the reflective film comprises the following raw materials by mass percentage: 15% - 20% of white inorganic filler, and the balance of polyethylene terephthalate; the white inorganic filler is at least one of nano calcium carbonate, titanium dioxide, barium sulfate, alumina, and silica.

[0015] Among them, the reflective film is prepared by mixing the white inorganic filler and polyethylene terephthalate and then through conventional melt extrusion and biaxial stretching processes.

[0016] Preferably, the thickness of the transparent base film is 50 - 75 μm, the thickness of the reflective film is 75 - 125 μm, and the thickness of the hot melt adhesive layer is 3 - 5 μm; preferably, the thickness of the transparent base film is 50 μm, 60 μm, or 75 μm, and the thickness of the reflective film is 75 μm, 80 μm, 100 μm, or 125 μm.

[0017] A preparation method of the optical reflective composite film described above, comprising the following steps:

[0018] S1. Coat a primer on one surface of the transparent base film, melt - extrude at least one of EVA, EAA, and EMA, and then compound it onto the surface of the transparent base film coated with the primer by a casting method to form a hot melt adhesive layer, obtaining a first composite film;

[0019] S2. Coat the coating liquid for preparing the reflective coating on one surface of the reflective film, and after drying, form a reflective coating to obtain a second composite film;

[0020] S3. Thermally press - bond the first composite film and the second composite film to obtain the product.

[0021] In the present invention, the temperature and pressure of the thermal press - bonding are not particularly limited. Preferably, in S3, the temperature of the thermal press - bonding is 210 - 220 °C, and the pressure is 0.35 - 0.4 MPa.

[0022] In S3, the surface of the first composite film having a hot melt adhesive layer is thermocompression bonded to the surface of the second composite film having a reflective coating.

[0023] The beneficial effects of the present invention are as follows:

[0024] Compared with the reflective film and its preparation process in the prior art, the reflective film of the present invention has a reasonable structure, which is successively composed of a transparent base film, a hot melt adhesive layer, a reflective coating, and a reflective film; zinc oxide / titanium dioxide + glass micro powder is selected as the active ingredient of the reflective coating, combined with the reflective film containing white inorganic fillers, which can not only reduce costs but also ensure good reflection effects, enabling it to meet the requirements for reflection effects in the OLED lighting field; silane-modified polyolefin is selected as the base material of the reflective coating, which has good adhesion to inorganic powders such as metal oxides and glass micro powder, and can form a uniform and stable reflective coating; hot melt adhesive coating is selected to replace the coating of thermosetting phenolic resin adhesives as the bonding layer, and the composite is carried out by a thermocompression process, greatly reducing the production cost, significantly improving the production efficiency, and the production process has a significant green environmental protection effect, and is applicable to the reflective film in the OLED lighting field. Description of the Drawings

[0025] Figure 1 It is a schematic structural diagram of the optical reflective composite film proposed by the present invention. Figure 1 In it, 1 - transparent base film, 2 - hot melt adhesive layer, 3 - reflective film, 4 - reflective coating. Specific Embodiments

[0026] Next, the technical solutions of the present invention will be described in detail through specific embodiments.

[0027] Example 1

[0028] An optical reflective composite film is successively composed of a transparent base film, a hot melt adhesive layer, a reflective film, and a reflective coating;

[0029] The reflective coating includes the following components by mass percentage: 60% metal oxide, 5% glass micro powder, 35% silane-modified polyolefin; among them, the metal oxide is composed of zinc oxide and titanium dioxide in a mass ratio of 2:1.

[0030] The transparent base film is a biaxially oriented polypropylene film, and the PPY polypropylene film of Guofeng Plastics Industry is used.

[0031] The reflective film includes the following raw materials by mass percentage: 15% nano calcium carbonate, 85% polyethylene terephthalate; the reflective film is prepared by mixing nano calcium carbonate and polyethylene terephthalate and then through conventional melt extrusion and biaxial stretching processes.

[0032] The thickness of the transparent base film is 50 μm, the thickness of the reflective film is 75 μm, and the thickness of the hot melt adhesive layer is 3 μm.

[0033] The preparation method of the above optical reflective composite film includes the following steps:

[0034] S1. Coating a primer on one surface of the transparent base film. After melting and extruding EVA at 240 - 270 °C, it is compounded onto the surface of the transparent base film coated with the primer by the casting method to form a hot melt adhesive layer, obtaining a first composite film. The primer is a polyethyleneimine (EPI) solution (mixed by EPI, water, and ethanol in a mass ratio of 17:150:25), and the coating amount of the primer is 4 g / m 2 ;

[0035] S2. Coating a coating solution with a solid content of 2.5 wt% on one surface of the reflective film, with a coating amount of 7 g / m 2 , and forming a reflective coating after drying to obtain a second composite film. The coating solution includes the following raw materials: random polypropylene, vinyltrimethoxysilane, azobisisobutyronitrile, metal oxide, glass micro powder, and ethyl acetate; the mass ratio of random polypropylene, vinyltrimethoxysilane, and azobisisobutyronitrile is 10:2.5:0.3;

[0036] S3. Thermally pressing and laminating the surface of the first composite film with the hot melt adhesive layer and the surface of the second composite film with the reflective coating under the conditions of a temperature of 210 °C and a pressure of 0.35 MPa to obtain the product.

[0037] Example 2

[0038] An optical reflective composite film is composed of a transparent base film, a hot melt adhesive layer, a reflective coating, and a reflective film in sequence;

[0039] The reflective coating includes components with the following mass percentages: 62% metal oxide, 8% glass micro powder, 30% silane - modified polyolefin; the metal oxide is composed of zinc oxide and titanium dioxide in a mass ratio of 2.5:1.

[0040] The transparent base film is a biaxially oriented polypropylene film, the PPAC polypropylene film of Guofeng Plastics Industry.

[0041] The reflective film includes raw materials with the following mass percentages: 18% titanium dioxide, 82% polyethylene terephthalate; the reflective film is obtained by mixing titanium dioxide and polyethylene terephthalate and then through conventional melting extrusion and biaxial stretching processes.

[0042] The thickness of the transparent base film is 60 μm, the thickness of the reflective film is 100 μm, and the thickness of the hot melt adhesive layer is 4 μm.

[0043] The preparation method of the above optical reflection composite film includes the following steps:

[0044] S1. Coating a primer on one surface of a transparent base film. After melting and extruding EAA at 240 - 270 °C, it is compounded onto the surface of the transparent base film coated with the primer by a casting method to form a hot melt adhesive layer, obtaining a first composite film. The primer is a polyethyleneimine (EPI) solution (composed of EPI, water, and ethanol mixed in a mass ratio of 17:150:25), and the coating amount of the primer is 4.5 g / m 2 ;

[0045] S2. Coating a coating solution with a solid content of 4.0 wt% on one surface of a reflective film, with a coating amount of 8 g / m 2 , and after drying, a reflective coating is formed to obtain a second composite film. The coating solution includes the following raw materials: chlorinated modified polypropylene, vinyltrimethoxysilane, azobisisobutyronitrile, metal oxide, glass micro powder, and ethyl acetate; the mass ratio of chlorinated modified polypropylene, vinyltrimethoxysilane, and azobisisobutyronitrile is 15:5:1.5;

[0046] S3. Thermally pressing and laminating the surface of the first composite film with the hot melt adhesive layer and the surface of the second composite film with the reflective coating under the conditions of a temperature of 215 °C and a pressure of 0.38 MPa to obtain the product.

[0047] Example 3

[0048] An optical reflection composite film is successively composed of a transparent base film, a hot melt adhesive layer, a reflective coating, and a reflective film;

[0049] The reflective coating includes components with the following mass percentages: 65% metal oxide, 10% glass micro powder, 25% silane - modified polyolefin; the metal oxide is composed of zinc oxide and titanium dioxide in a mass ratio of 3:1.

[0050] The transparent base film is a biaxially oriented polyethylene terephthalate film, the PETT polyethylene terephthalate film of Guofeng Plastics Industry.

[0051] The reflective film includes raw materials with the following mass percentages: 20% barium sulfate, 80% polyethylene terephthalate; the reflective film is obtained by mixing barium sulfate and polyethylene terephthalate and then through conventional melting extrusion and biaxial stretching processes.

[0052] The thickness of the transparent base film is 75 μm, the thickness of the reflective film is 125 μm, and the thickness of the hot melt adhesive layer is 5 μm.

[0053] The preparation method of the above optical reflection composite film includes the following steps:

[0054] S1. Coating a primer on one surface of a transparent base film. After melting and extruding EMA at 240 - 270 °C, it is compounded onto the surface of the transparent base film coated with the primer by a casting method to form a hot melt adhesive layer, obtaining a first composite film. The primer is a polyethyleneimine (EPI) solution (composed of EPI, water, and ethanol mixed in a mass ratio of 17:150:25), and the coating amount of the primer is 5 g / m 2 ;

[0055] S2. Coating a coating solution with a solid content of 5.0 wt% on one surface of a reflective film, with a coating amount of 10 g / m 2 , and forming a reflective coating after drying to obtain a second composite film. The coating solution includes the following raw materials: atactic polypropylene, vinyltrimethoxysilane, azobisisobutyronitrile, metal oxide, glass micro powder, and ethyl acetate; the mass ratio of atactic polypropylene, vinyltrimethoxysilane, and azobisisobutyronitrile is 20:7:3;

[0056] S3. Thermally pressing and laminating the surface of the first composite film with the hot melt adhesive layer and the surface of the second composite film with the reflective coating under the conditions of a temperature of 220 °C and a pressure of 0.4 MPa to obtain the product.

[0057] As described above, it is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, making equivalent substitutions or changes should be covered within the protection scope of the present invention.

Claims

1. An optical reflection composite film, characterized in that, It is successively composed of a transparent base film, a hot melt adhesive layer, a reflective coating, and a reflective film; The reflective coating comprises components in the following mass percentages: 60%-65% of metal oxide, 5%-10% of glass micro-powder, and the balance is silane-modified polyolefin; the metal oxide is zinc oxide, titanium dioxide or a combination thereof; The raw material of the hot melt adhesive layer is at least one of EVA, EAA, and EMA; The reflective film comprises raw materials in the following mass percentages: 15%-20% of white inorganic filler, and the balance is polyethylene terephthalate; the white inorganic filler is at least one of nano calcium carbonate, titanium dioxide, barium sulfate, alumina, and silicon dioxide; The preparation method of the optical reflective composite film comprises the following steps: S1. Coating a primer on one surface of the transparent base film, melting and extruding at least one of EVA, EAA, and EMA, and then compounding it onto the surface of the transparent base film coated with the primer by a casting method to form a hot melt adhesive layer, obtaining a first composite film; S2. Coating the coating liquid for preparing the reflective coating on one surface of the reflective film, and drying to form a reflective coating, obtaining a second composite film; S3. Thermally pressing and laminating the first composite film and the second composite film to obtain the product.

2. The optical reflection composite film according to claim 1, characterized in that, The reflective coating is formed by coating the coating liquid on one surface of the reflective film and drying. The coating liquid comprises the following raw materials: polyolefin, alkenyl-containing silane monomer, initiator, metal oxide, glass micro-powder, and solvent; the mass ratio of the polyolefin, alkenyl-containing silane monomer to the initiator is (10-20):(2.5-7):(0.3-3).

3. The optical reflection composite film according to claim 2, wherein The solid content of the coating solution is 2.5 - 5.0 wt%, and the coating amount is 7 - 10 g / m 2 , and the solvent is at least one of ethyl acetate, butyl acetate, acetone, and ethanol.

4. The optical reflection composite film according to claim 1, wherein The mass ratio of the zinc oxide to the titanium dioxide is (2-3):

1.

5. The optical reflection composite film according to claim 1, wherein The transparent base film is a biaxially oriented polypropylene film or a biaxially oriented polyethylene terephthalate film.

6. The optical reflection composite film according to claim 1, characterized in that, The thickness of the transparent base film is 50-75μm, the thickness of the reflective film is 75-125μm, and the thickness of the hot melt adhesive layer is 3-5μm.

7. The optical reflection composite film according to claim 1, characterized in that, In S3, the temperature of the thermal pressing and lamination is 210-220°C, and the pressure is 0.35-0.4MPa.

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