An ultraviolet-blocking optical adhesive and its preparation method

Abstract

The present invention relates to the field of optical adhesives, and particularly relates to an ultraviolet ray blocking optical adhesive and a preparation method thereof. In order to solve the problem that the ultraviolet ray blocking property of the existing optical adhesive is not persistent, the present invention provides an ultraviolet ray blocking optical adhesive and a preparation method thereof. The optical adhesive sequentially includes a first release film, a first adhesive layer, a hardening layer, a substrate, a second adhesive layer and a second release film. This ultraviolet ray blocking optical adhesive has high ultraviolet ray blocking property and the ultraviolet ray blocking property is persistent.

Description

Technical Field

[0001] The present invention relates to the field of optical adhesives, and particularly to an ultraviolet-blocking optical adhesive and a preparation method thereof. Background Art

[0002] Optically Clear Adhesive (OCA) is a special adhesive mainly used for bonding optical elements. It is required to be colorless and transparent, with a transmittance of more than 90%, good bonding strength, and low shrinkage during curing.

[0003] Optical adhesives are mainly important raw materials for optical displays, bonding the three major components in optical displays, namely, protective glass, touch screen, and display screen, together. The full lamination technology is the mainstream development trend for the lamination of high-end smartphones and tablet computer panels. Optical adhesives are generally made into a substrate-free structure, and then a release film is laminated on each of the upper and lower layers to form a double-sided adhesive tape without a matrix material.

[0004] In recent years, with the upgrading of optical displays, many high-end components in displays are very sensitive to ultraviolet rays. However, traditional optical adhesives cannot block ultraviolet rays, resulting in the aging of optical components, shortened service life, and weakened display effects. The current solution is to add an organic ultraviolet absorber to the optical adhesive. The organic ultraviolet absorber usually has three types: benzophenone, salicylate, and benzotriazole, which absorb ultraviolet rays in different wavelength bands, enabling the composition of the optical adhesive to have the function of blocking ultraviolet rays in the range of 200 - 400 nm. The principle is that the organic ultraviolet absorber undergoes a chemical reaction and molecular rearrangement after absorbing ultraviolet rays, converting ultraviolet rays into harmless heat energy and releasing it. The optical adhesive of this solution can protect optical components for a certain period of time. After a period of time, on the one hand, the organic ultraviolet absorber will be consumed, and on the other hand, since the organic ultraviolet absorber does not react with the colloid, it will precipitate from the optical adhesive. These will all cause a decrease in the ultraviolet-blocking performance of the optical adhesive. Summary of the Invention

[0005] In order to solve the problem of the non-persistent ultraviolet-blocking property of existing optical adhesives, the present invention provides an ultraviolet-blocking optical adhesive and a preparation method thereof. The ultraviolet-blocking optical adhesive has high ultraviolet-blocking property and the ultraviolet-blocking property is persistent.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions.

[0007] The present invention provides an ultraviolet-blocking optical adhesive (abbreviated as OCA), and the optical adhesive sequentially includes a first adhesive layer, a hardening layer, a substrate, and a second adhesive layer.

[0008] Further, the optical adhesive sequentially includes a first release film, a first adhesive layer, a hardening layer, a substrate, and a second adhesive layer.

[0009] Further, the optical adhesive sequentially includes a first release film, a first adhesive layer, a hardening layer, a substrate, a second adhesive layer, and a second release film.

[0010] The hardening layer is formed after the hardening layer coating solution (referred to as the hard coating solution) is cured.

[0011] Further, the hardening layer coating solution includes the following components: 30-40 parts by weight of a tetrafunctional aliphatic polyurethane acrylate oligomer, 28-40 parts by weight of trimethylolpropane triacrylate, 3-5 parts by weight of modified titanium dioxide particles, 0.5-0.9 parts by weight of photoinitiator 184, 0.1-0.5 parts by weight of leveling agent BYK-333, and 25-27 parts by weight of a solvent are mixed. The total parts of the tetrafunctional aliphatic polyurethane acrylate oligomer, trimethylolpropane triacrylate, modified titanium dioxide particles, photoinitiator, leveling agent, and solvent are 100 parts by weight. Further, the 25-27 parts by weight of the solvent includes 13-15 parts by weight of solvent methyl ethyl ketone, and 10-12 parts by weight of solvent propylene glycol monomethyl ether.

[0012] Further, the photoinitiator is photoinitiator 184. Further, the leveling agent is leveling agent BYK-333.

[0013] The first adhesive layer is formed after the optical adhesive coating solution is cured.

[0014] The second adhesive layer is formed after the optical adhesive coating solution is cured.

[0015] The formulation compositions of the first adhesive layer and the second adhesive layer can be the same or different.

[0016] The first adhesive layer and the second adhesive layer can be collectively referred to as the adhesive layer.

[0017] The optical adhesive coating solution (also known as the optical adhesive glue) includes the following components: 30-50 parts by weight of a polyacrylate prepolymer, 5-15 parts by weight of methacrylate, 5-15 parts by weight of butyl acrylate, 2-4 parts by weight of azobisisobutyronitrile, 1-3 parts by weight of polysilane, 1-3 parts by weight of n-dodecyl mercaptan, 0.2-0.6 parts by weight of a leveling agent, 1.8-2.7 parts by weight of triphenyl glycidyl ether methane, and 30 parts by weight of a solvent. The total parts of the polyacrylate prepolymer, methacrylate, butyl acrylate, azobisisobutyronitrile, polysilane, n-dodecyl mercaptan, leveling agent, triphenyl glycidyl ether methane, and solvent are 100 parts by weight. Further, the 30 parts by weight of the solvent includes 15 parts by weight of solvent toluene and 15 parts by weight of solvent ethyl acetate. Further, the leveling agent is leveling agent BYK-333.

[0018] Synthesis method of the polyacrylate prepolymer: Pour 70 parts by weight of methyl methacrylate, 29.5 parts by weight of butyl acrylate, and 0.5 parts by weight of azobisisobutyronitrile into a reaction kettle, react at 90 °C for 3 hours, then cool down to 50 °C and react for 12 hours to obtain the polyacrylate prepolymer.

[0019] Further, the hardening layer coating solution comprises the following components: 35 parts by weight of a tetrafunctional aliphatic polyurethane acrylate oligomer, 35 parts by weight of trimethylolpropane triacrylate, 4 parts by weight of modified titanium dioxide particles, 0.5 parts by weight of photoinitiator 184, 0.5 parts by weight of leveling agent BYK-333, and 25 parts by weight of a solvent are mixed. Further, the 25 - 27 parts by weight of the solvent comprises 15 parts by weight of solvent methyl ethyl ketone and 10 parts by weight of solvent propylene glycol monomethyl ether. The optical adhesive coating solution (also known as optical adhesive glue) comprises the following components: 40 parts by weight of polyacrylate prepolymer, 10 parts by weight of methacrylate, 10 parts by weight of butyl acrylate, 3 parts by weight of azobisisobutyronitrile, 2 parts by weight of polysilane, 3 parts by weight of n-dodecyl mercaptan, 0.2 parts by weight of leveling agent BYK-333, 1.8 parts by weight of triphenyl glycidyl ether methane, and 30 parts by weight of a solvent. Further, the 30 parts by weight of the solvent comprises 15 parts by weight of solvent toluene and 15 parts by weight of solvent ethyl acetate. The foregoing technical solution includes Example 1.

[0020] Further, the substrate is a TPU film.

[0021] Further, the modified titanium dioxide particles are DK-TiO2-T30Q of Beijing Decode Island Gold Technology Co., Ltd.

[0022] Further, the thickness of the substrate is 25 - 35 μm. The thickness of the hardening layer is 1 μm. The thickness of the first adhesive layer is 10 μm. The thickness of the second adhesive layer is 10 μm.

[0023] The present invention provides a preparation method of the ultraviolet blocking optical adhesive, and the method comprises the following steps:

[0024] (1) Coat the hardening layer coating solution on one side of the substrate, dry the formed coating at 80 - 90 °C for 4 minutes, and then cure the dried coating by ultraviolet rays of a high-pressure mercury lamp to obtain the hardening layer;

[0025] (2) Coat a layer of optical adhesive coating solution on a second release film, heat the formed coating at 100 - 120 °C for 4 minutes to obtain the second adhesive layer.

[0026] (3) Coat a layer of optical adhesive coating solution on the above hardening layer, heat the formed coating at 100 - 120 °C for 4 minutes to obtain the first adhesive layer.

[0027] (4) Bond the second adhesive layer to the untreated surface of the substrate to obtain the final product.

[0028] The present invention has the following advantages compared with the prior art:

[0029] 1. The optical adhesive of the present invention is composed of a substrate, a hardening layer, a first adhesive layer and a second adhesive layer. By adding modified titanium dioxide particles to the hardening layer, the UV blocking effect of the entire structure is achieved. Since the particles are bound in the hardening layer and will not precipitate, and at the same time, the modified titanium dioxide particles in this structure can absorb, reflect and scatter ultraviolet rays without being consumed themselves, having a long-lasting UV blocking effect.

[0030] 2. The optical adhesive of the present invention is made of the structure of a hardening layer, a first adhesive layer and a second adhesive layer. The curing shrinkage of the first adhesive layer and the second adhesive layer is offset, which makes the warpage of this optical adhesive structure lower than that of general optical adhesives. Description of the Drawings

[0031] Figure 1 It is a schematic structural diagram of the UV blocking optical adhesive provided by the present invention. Detailed Embodiments

[0032] The present invention will be specifically described below in conjunction with specific embodiments and drawings, but the present invention is not limited thereto.

[0033] As Figure 1 shown, the UV blocking optical adhesive provided by the present invention includes a substrate 1, a hardening layer 2 and an adhesive layer. The adhesive layer includes a first adhesive layer 3 and a second adhesive layer 4, a first release film 5 and a second release film 6.

[0034] Furthermore, the preparation method of the optical adhesive provided by the present invention is as follows: Prepare a hardening layer coating solution, coat it on the substrate, dry the formed coating at 80 - 90 °C for 4 minutes, and then cure the dried coating by ultraviolet rays of a high-pressure mercury lamp to obtain the hardening layer. Then prepare the optical adhesive glue, coat it on the hardening layer, heat the formed coating at 100 - 120 °C for 4 minutes to obtain the first adhesive layer. Then coat the optical adhesive glue on the second release film, heat the formed coating at 100 - 120 °C for 4 minutes to obtain the second adhesive layer. Finally, bond the second adhesive layer to the other side of the substrate to obtain the final product.

[0035] The performance of the UV blocking optical adhesive provided by the present invention is tested according to the following method:

[0036] (1) Haze, total light transmittance

[0037] Use a Nippon Denshoku NDH 2000N haze meter and measure it by the transmission method.

[0038] The UV-blocking optical adhesive provided by the present invention is used in optical devices. If the haze is too high, it will affect the display effect, and generally the haze is required to be less than 1.

[0039] (2) UV blocking rate

[0040] Use a Shanghai Yidian L5 / L5S spectrophotometer to measure the transmittance of the product in the wavelength range of 300 - 380 nm. Use the formula Z = 1 - T, where T represents the average transmittance in the wavelength range of 300 - 380 nm, and Z represents the average blocking rate in the wavelength range of 300 - 380 nm.

[0041] (3) UV blocking rate after QUV irradiation

[0042] Put the product into a Haida International HD-E802-4 ultraviolet light accelerated weathering test machine and irradiate it for 1000 hours. Then use a Shanghai Yidian L5 / L5S spectrophotometer to measure the transmittance of the product in the wavelength range of 300 - 380 nm. Use the formula Z = 1 - T, where T represents the average transmittance in the wavelength range of 300 - 380 nm, and Z represents the average blocking rate in the wavelength range of 300 - 380 nm.

[0043] (4) Weather resistance

[0044] Put the product into a Haida International HD-E702-15 thermostatic and humidostatic weathering test machine and place it for 500 hours under the conditions of 85% RH and 85°C, and observe whether the product turns white or hazy.

[0045] Judgment criteria

[0046] If the appearance has no change, judge as "Pass" (qualified);

[0047] If the appearance turns white or hazy, judge as "NG" (unqualified).

[0048] (5) Warpage

[0049] Cut the product into a size of 10 cm × 10 cm and place it on a marble tabletop. Use a steel straightedge to measure the height of the four corners, and take the maximum value as the warpage value.

[0050] Example 1

[0051] The present invention provides a UV-blocking optical adhesive, as Figure 1 shown, the optical adhesive includes a substrate 1, a hardening layer 2 and an adhesive layer, and the adhesive layer includes a first adhesive layer 3 and a second adhesive layer 4.

[0052] 35 parts by weight of a tetrafunctional aliphatic polyurethane acrylate oligomer, 35 parts by weight of trimethylolpropane triacrylate, 4 parts by weight of modified titanium dioxide particles DK-TiO2-T30Q, 0.5 parts by weight of photoinitiator 184, 0.5 parts by weight of leveling agent BYK-333, 15 parts by weight of solvent methyl ethyl ketone, and 10 parts by weight of solvent propylene glycol monomethyl ether were mixed to obtain a curing layer coating solution.

[0053] The above-mentioned curing layer coating solution was coated on one surface of an optical-grade TPU film (Huizhou Yidu High-tech New Materials Co., Ltd., trade name; T-25-J2) with a thickness of 25 μm. After drying the formed coating at 80 - 90 °C for 2 minutes, the dried coating was cured by ultraviolet irradiation with a light quantity of 300 mJ / cm 2 to obtain a curing layer with a coating thickness of 1 μm.

[0054] 70 parts by weight of methyl methacrylate, 29.5 parts by weight of butyl acrylate, and 0.5 parts by weight of azobisisobutyronitrile were poured into a reaction kettle and reacted at 90 °C for 3 hours, then cooled to 50 °C and reacted for 12 hours to obtain a polyacrylate prepolymer.

[0055] 40 parts by weight of the polyacrylate prepolymer, 10 parts by weight of methacrylate, 10 parts by weight of butyl acrylate, 3 parts by weight of azobisisobutyronitrile, 2 parts by weight of polysilane, 3 parts by weight of n-dodecyl mercaptan, 0.2 parts by weight of leveling agent BYK-333, 1.8 parts by weight of triphenyl glycidyl ether methane, 15 parts by weight of solvent toluene, and 15 parts by weight of solvent ethyl acetate were mixed to obtain an optical adhesive glue.

[0056] The above-mentioned optical adhesive glue was coated on the above-mentioned curing layer, and the formed glue layer was heated at 110 °C for 4 minutes, and then a first release film with a release force of 5 gf / 25 mm was covered to obtain a first glue layer with a glue layer thickness of 10 μm.

[0057] The above-mentioned optical adhesive glue was coated on a second release film with a release force of 15 gf / 25 mm, and the formed glue layer was heated at 110 °C for 4 minutes, and then a third release film with a release force of 5 gf / 25 mm was covered to obtain a second glue layer with a glue layer thickness of 10 μm.

[0058] The third release film with a release force of 5 gf / 25 mm in the above-mentioned second glue layer was torn off, and the second glue layer was adhered to the other side of the above-mentioned substrate to obtain the final product.

[0059] Example 2

[0060] The optical adhesive as provided in Example 1. The manufacturing method is as follows:

[0061] Mix 40 parts by weight of a tetrafunctional aliphatic polyurethane acrylate oligomer, 28 parts by weight of trimethylolpropane triacrylate, 4 parts by weight of modified titanium dioxide particles DK-TiO2-T30Q, 0.9 parts by weight of photoinitiator 184, 0.1 parts by weight of leveling agent BYK-333, 15 parts by weight of solvent methyl ethyl ketone, and 12 parts by weight of solvent propylene glycol monomethyl ether to obtain a hardening layer coating solution (which can be abbreviated as the hardening layer coating liquid).

[0062] Coat the above hardening layer coating solution on one surface of an optical-grade TPU film (Huizhou Yidu High-Tech New Materials Co., Ltd., trade name; T-25-J2) with a thickness of 25 μm. After drying the formed coating at 80 - 90 °C for 2 minutes, cure the dried coating by ultraviolet irradiation with a light quantity of 300 mJ / cm 2 to obtain a hardening layer with a coating thickness of 1 μm.

[0063] Mix 50 parts by weight of polyacrylate prepolymer B, 5 parts by weight of methacrylate, 5 parts by weight of butyl acrylate, 2 parts by weight of azobisisobutyronitrile, 3 parts by weight of polysilane, 2 parts by weight of n-dodecyl mercaptan, 0.6 parts by weight of leveling agent BYK-333, 2.4 parts by weight of triphenyl glycidyl ether methane, 15 parts by weight of solvent toluene, and 15 parts by weight of solvent ethyl acetate to obtain an optical adhesive glue.

[0064] Coat the above optical adhesive glue on the above hardening layer, heat the formed glue layer at 110 °C for 4 minutes, and cover it with a first release film with a release force of 5 gf / 25 mm to obtain a first glue layer with a glue layer thickness of 10 μm.

[0065] Then coat the above optical adhesive glue on a second release film with a release force of 15 gf / 25 mm, heat the formed glue layer at 110 °C for 4 minutes, and cover it with a third release film with a release force of 5 gf / 25 mm to obtain a second glue layer with a glue layer thickness of 10 μm.

[0066] Tear off the third release film with a release force of 5 gf / 25 mm in the above second glue layer, and bond the second glue layer to the other surface of the above substrate to obtain the final product.

[0067] Example 3

[0068] The optical adhesive as provided in Example 1. The preparation method is as follows:

[0069] Mix 35 parts by weight of a tetrafunctional aliphatic polyurethane acrylate oligomer, 36 parts by weight of trimethylolpropane triacrylate, 3 parts by weight of modified titanium dioxide particles DK-TiO2-T30Q, 0.8 part by weight of photoinitiator 184, 0.2 part by weight of leveling agent BYK-333, 13 parts by weight of solvent methyl ethyl ketone, and 12 parts by weight of solvent propylene glycol monomethyl ether to obtain a hardening layer coating solution.

[0070] Coat one side of an optical-grade TPU film (Huizhou Yidu High-Tech New Materials Co., Ltd., trade name; T-35-J2) with a thickness of 35 μm with the above hardening layer coating solution. After drying the formed coating at 80 - 90 °C for 2 minutes, cure the dried coating by ultraviolet irradiation with a light amount of 300 mJ / cm2 to obtain a hardening layer with a coating thickness of 1 μm.

[0071] Mix 30 parts by weight of a polyacrylate prepolymer, 15 parts by weight of methacrylate, 15 parts by weight of butyl acrylate, 4 parts by weight of azobisisobutyronitrile, 1 part by weight of polysilane, 3 parts by weight of n-dodecyl mercaptan, 0.5 part by weight of leveling agent BYK-333, 1.5 parts by weight of triphenyl glycidyl ether methane, 15 parts by weight of solvent toluene, and 15 parts by weight of solvent ethyl acetate to obtain an optical adhesive glue.

[0072] Coat the above optical adhesive glue onto the above hardening layer, heat the formed adhesive layer at 110 °C for 4 minutes, and cover it with a first release film with a release force of 5 gf / 25 mm to obtain a first adhesive layer with an adhesive layer thickness of 10 μm.

[0073] Coat the above optical adhesive glue onto a second release film with a release force of 15 gf / 25 mm, heat the formed adhesive layer at 110 °C for 4 minutes, and cover it with a third release film with a release force of 5 gf / 25 mm to obtain a second adhesive layer with an adhesive layer thickness of 10 μm.

[0074] Tear off the third release film with a release force of 5 gf / 25 mm in the above second adhesive layer, and bond the second adhesive layer to the other side of the above substrate to obtain the final product.

[0075] Example 4

[0076] The optical adhesive as provided in Example 1. The preparation method is as follows:

[0077] Mix 30 parts by weight of a tetrafunctional aliphatic polyurethane acrylate oligomer, 38 parts by weight of trimethylolpropane triacrylate, 5 parts by weight of modified titanium dioxide particles DK-TiO2-T30Q, 0.7 part by weight of photoinitiator 184, 0.3 part by weight of leveling agent BYK-333, 14 parts by weight of solvent methyl ethyl ketone, and 12 parts by weight of solvent propylene glycol monomethyl ether to obtain a hardening layer coating solution.

[0078] Apply the above-mentioned hardening layer coating solution onto one surface of an optical-grade TPU film (Huizhou Yidu High-Tech New Materials Co., Ltd., trade name: T-30-J2) with a thickness of 30 microns. After drying the formed coating at 80 - 90 °C for 2 minutes, cure the dried coating by ultraviolet irradiation with a light quantity of 300 mJ / cm 2 , to obtain a hardening layer with a coating thickness of 1 μm.

[0079] Mix 35 parts by weight of a polyacrylate prepolymer, 15 parts by weight of a methacrylate, 10 parts by weight of butyl acrylate, 3 parts by weight of azobisisobutyronitrile, 3 parts by weight of polysilane, 1 part by weight of n-dodecyl mercaptan, 0.2 part by weight of a leveling agent BYK-333, 2.8 parts by weight of triphenyl glycidyl ether methane, 15 parts by weight of a solvent toluene, and 15 parts by weight of a solvent ethyl acetate to obtain an optical adhesive glue.

[0080] Apply the above-mentioned optical adhesive glue onto the above-mentioned hardening layer, heat the formed adhesive layer at 110 °C for 4 minutes, and cover it with a first release film with a release force of 5 gf / 25 mm to obtain a first adhesive layer with an adhesive layer thickness of 10 μm.

[0081] Then apply the above-mentioned optical adhesive glue onto a second release film with a release force of 15 gf / 25 mm, heat the formed adhesive layer at 110 °C for 4 minutes, and cover it with a third release film with a release force of 5 gf / 25 mm to obtain a second adhesive layer with an adhesive layer thickness of 10 μm.

[0082] Tear off the third release film with a release force of 5 gf / 25 mm in the above-mentioned second adhesive layer, and bond the second adhesive layer to the other surface of the above-mentioned substrate to obtain the final product.

[0083] Example 5

[0084] The optical adhesive as provided in Example 1. The preparation method is as follows:

[0085] Mix 30 parts by weight of a tetrafunctional aliphatic polyurethane acrylate oligomer, 40 parts by weight of trimethylolpropane triacrylate, 3 parts by weight of modified titanium dioxide particles DK-TiO2-T30Q, 0.8 part by weight of a photoinitiator 184, 0.2 part by weight of a leveling agent BYK-333, 14 parts by weight of a solvent methyl ethyl ketone, and 12 parts by weight of a solvent propylene glycol monomethyl ether to obtain a hardening layer coating solution.

[0086] Apply the above-mentioned hardening layer coating solution onto one surface of an optical-grade TPU film (Huizhou Yidu High-Tech New Materials Co., Ltd., trade name: T-25-J2) with a thickness of 25 microns. After drying the formed coating at 80 - 90 °C for 2 minutes, cure it by ultraviolet irradiation with a light quantity of 300 mJ / cm 2The amount of light is used to cure the dry coating by ultraviolet irradiation to obtain a hardened layer with a coating thickness of 1 μm.

[0087] 45 parts by weight of a polyacrylate prepolymer, 5 parts by weight of a methacrylate, 10 parts by weight of butyl acrylate, 2 parts by weight of azobisisobutyronitrile, 3 parts by weight of polysilane, 2 parts by weight of n-dodecyl mercaptan, 0.3 parts by weight of a leveling agent BYK-333, 2.7 parts by weight of triphenyl glycidyl ether methane, 15 parts by weight of the solvent toluene and 15 parts by weight of the solvent ethyl acetate are mixed to obtain an optical adhesive glue.

[0088] The above optical adhesive glue is coated on the above hardened layer, and the formed glue layer is heated at 110 °C for 4 minutes, and a first release film with a release force of 5 gf / 25 mm is covered to obtain a first glue layer with a glue layer thickness of 10 μm.

[0089] The above optical adhesive glue is further coated on a second release film with a release force of 15 gf / 25 mm, and the formed glue layer is heated at 110 °C for 4 minutes, and a third release film with a release force of 5 gf / 25 mm is covered to obtain a second glue layer with a glue layer thickness of 10 μm.

[0090] The third release film with a release force of 5 gf / 25 mm in the above second glue layer is torn off, and the second glue layer is adhered to the other side of the above substrate to obtain the final product.

[0091] Comparative Example 1

[0092] The provided optical adhesive. The preparation method is as follows:

[0093] 39 parts by weight of a tetrafunctional aliphatic polyurethane acrylate oligomer, 35 parts by weight of trimethylolpropane triacrylate, 0.5 parts by weight of a photoinitiator 184, 0.5 parts by weight of a leveling agent BYK-333, 13 parts by weight of the solvent methyl ethyl ketone, and 12 parts by weight of the solvent propylene glycol monomethyl ether are mixed to obtain a hardened layer coating solution.

[0094] The above hardened layer coating solution is coated on one surface of an optical grade TPU film (Huizhou Yidu High-Tech New Materials Co., Ltd., trade name; T-25-J2) with a thickness of 25 microns. After drying the formed coating at 80 - 90 °C for 2 minutes, with a light amount of 300 mJ / cm 2 The amount of light is used to cure the dry coating by ultraviolet irradiation to obtain a hardened layer with a coating thickness of 1 μm.

[0095] 70 parts by weight of methyl methacrylate, 29.5 parts by weight of butyl acrylate and 0.5 parts by weight of azobisisobutyronitrile are poured into a reaction kettle, reacted at 90 °C for 3 hours, and then cooled to 50 °C and reacted for 12 hours to obtain a prepolymer.

[0096] Mix 40 parts by weight of a polyacrylate prepolymer, 10 parts by weight of a methacrylate, 10 parts by weight of butyl acrylate, 3 parts by weight of azobisisobutyronitrile, 2 parts by weight of polysilane, 3 parts by weight of n-dodecyl mercaptan, 0.2 part by weight of leveling agent BYK-333, 1.8 parts by weight of triphenyl glycidyl ether methane, 15 parts by weight of solvent toluene and 15 parts by weight of solvent ethyl acetate to obtain an optical adhesive glue.

[0097] Coat the above optical adhesive glue onto the above hardening layer, heat the formed glue layer at 110 °C for 4 minutes, cover with a first release film having a release force of 5 gf / 25 mm to obtain a first glue layer with a glue layer thickness of 10 μm.

[0098] Then coat the above optical adhesive glue onto a second release film having a release force of 15 gf / 25 mm, heat the formed glue layer at 110 °C for 4 minutes, cover with a third release film having a release force of 5 gf / 25 mm to obtain a second glue layer with a glue layer thickness of 10 μm.

[0099] Tear off the third release film with a release force of 5 gf / 25 mm in the above second glue layer, bond the second glue layer to the other side of the above substrate to obtain the final product. Compared with the technical solution provided by the present invention, the difference of the composition provided by Comparative Example 1 is that the hardening layer does not contain modified titanium dioxide particles.

[0100] Comparative Example 2

[0101] Provide an optical adhesive, which sequentially includes a release film, a glue layer and a release film from top to bottom. The preparation method is as follows:

[0102] Pour 70 parts by weight of methyl methacrylate, 29.5 parts by weight of butyl acrylate and 0.5 part by weight of azobisisobutyronitrile into a reaction kettle, react at 90 °C for 3 hours, and then cool down to 50 °C and react for 12 hours to obtain a prepolymer.

[0103] Mix 40 parts by weight of a polyacrylate prepolymer, 10 parts by weight of a methacrylate, 7 parts by weight of butyl acrylate, 3 parts by weight of a benzotriazole ultraviolet absorber, 3 parts by weight of azobisisobutyronitrile, 2 parts by weight of polysilane, 3 parts by weight of n-dodecyl mercaptan, 0.2 part by weight of leveling agent BYK-333, 1.8 parts by weight of triphenyl glycidyl ether methane, 15 parts by weight of solvent toluene and 15 parts by weight of solvent ethyl acetate to obtain an optical adhesive glue.

[0104] Coat the above optical adhesive glue onto a release film having a release force of 15 gf / 25 mm, heat the formed glue layer at 110 °C for 4 minutes, cover with a release film having a release force of 5 gf / 25 mm to obtain an optical adhesive product with a glue layer thickness of 25 μm.

[0105] Compared with the technical solution provided by the present invention, the optical adhesive provided in Comparative Example 2 is different in that it is a single-layer structure, and an organic ultraviolet absorber is used in the adhesive layer.

[0106] Comparative Example 3

[0107] An optical adhesive is provided. The preparation method is as follows:

[0108] Mix 33 parts by weight of a tetrafunctional aliphatic polyurethane acrylate oligomer, 35 parts by weight of trimethylolpropane triacrylate, 6 parts by weight of modified titanium dioxide particles DK-TiO2-T30Q, 0.5 part by weight of photoinitiator 184, 0.5 part by weight of leveling agent BYK-333, 15 parts by weight of solvent methyl ethyl ketone, and 10 parts by weight of solvent propylene glycol monomethyl ether to obtain a hardening layer coating solution.

[0109] Coat the above hardening layer coating solution on one side of an optical-grade TPU film (Huizhou Yidu High-tech New Materials Co., Ltd., trade name; T-35-J2) with a thickness of 35 microns. After drying the formed coating at 80 - 90 °C for 2 minutes, cure the dried coating by ultraviolet irradiation with a light quantity of 300 mJ / cm 2 to obtain a hardening layer with a coating thickness of 1 μm.

[0110] Pour 70 parts by weight of methyl methacrylate, 29.5 parts by weight of butyl acrylate, and 0.5 part by weight of azobisisobutyronitrile into a reaction kettle, react at 90 °C for 3 hours, and then cool down to 50 °C and react for 12 hours to obtain a polyacrylate prepolymer.

[0111] Mix 40 parts by weight of polyacrylate prepolymer, 10 parts by weight of methacrylate, 10 parts by weight of butyl acrylate, 3 parts by weight of azobisisobutyronitrile, 2 parts by weight of polysilane, 3 parts by weight of n-dodecyl mercaptan, 0.2 part by weight of leveling agent BYK-333, 1.8 parts by weight of triphenyl glycidyl ether methane, 15 parts by weight of solvent toluene, and 15 parts by weight of solvent ethyl acetate to obtain an optical adhesive glue.

[0112] Coat the above optical adhesive glue on the above hardening layer, heat the formed adhesive layer at 110 °C for 4 minutes, and cover with a first release film with a release force of 5 gf / 25 mm to obtain a first adhesive layer with an adhesive layer thickness of 10 μm.

[0113] Then coat the above optical adhesive glue on a second release film with a release force of 15 gf / 25 mm, heat the formed adhesive layer at 110 °C for 4 minutes, and cover with a third release film with a release force of 5 gf / 25 mm to obtain a second adhesive layer with an adhesive layer thickness of 10 μm.

[0114] Peel off the third release film with a release force of 5 gf / 25 mm in the second adhesive layer above, and bond the second adhesive layer to the other side of the above-mentioned substrate to obtain the final product. Compared with the technical solution provided by the present invention, the difference between the optical adhesive product provided by Comparative Example 3 is that the hardening layer contains excessive modified titanium dioxide particles.

[0115] Table 1 Performance test results of the optical adhesives provided in the examples and comparative examples

[0116]

[0117] The optical adhesive provided by the present invention has good performance, has the ability to permanently block ultraviolet rays, and has the performance of low warpage, which is convenient for production and processing. Among them, the optical adhesive provided in Example 1 has the best comprehensive performance.

[0118] It should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the protection scope of the present invention. All equivalent changes and modifications made according to the content of the present invention are covered within the scope of the patent of the present invention.

Claims

1. An ultraviolet-blocking optical adhesive, characterized in that, The optical adhesive sequentially includes a first adhesive layer, a hardening layer, a substrate, and a second adhesive layer; The hardening layer is formed by curing a hardening layer coating solution; the hardening layer coating solution includes the following components: 30-40 parts by weight of a tetrafunctional aliphatic polyurethane acrylate oligomer, 28-40 parts by weight of trimethylolpropane triacrylate, 3-5 parts by weight of modified titanium dioxide particles, 0.5-0.9 parts by weight of a photoinitiator, 0.1-0.5 parts by weight of a leveling agent, and 25-27 parts by weight of a solvent; the total parts by weight of the tetrafunctional aliphatic polyurethane acrylate oligomer, trimethylolpropane triacrylate, modified titanium dioxide particles, photoinitiator, leveling agent, and solvent is 100 parts by weight; The first adhesive layer is formed by curing an optical adhesive coating solution; the second adhesive layer is formed by curing an optical adhesive coating solution; the optical adhesive coating solution includes the following components: 30-50 parts by weight of a polyacrylate prepolymer, 5-15 parts by weight of a methacrylate, 5-15 parts by weight of butyl acrylate, 2-4 parts by weight of azobisisobutyronitrile, 1-3 parts by weight of a polysilane, 1-3 parts by weight of n-dodecyl mercaptan, 0.2-0.6 parts by weight of a leveling agent, 1.8-2.7 parts by weight of triphenyl glycidyl ether methane, and 30 parts by weight of a solvent; the total parts by weight of the polyacrylate prepolymer, methacrylate, butyl acrylate, azobisisobutyronitrile, polysilane, n-dodecyl mercaptan, leveling agent, triphenyl glycidyl ether methane, and solvent is 100 parts by weight; The synthesis method of the polyacrylate prepolymer: Pour 70 parts by weight of methyl methacrylate, 29.5 parts by weight of butyl acrylate, and 0.5 parts by weight of azobisisobutyronitrile into a reaction kettle, react at 90 °C for 3 hours, and then cool down to 50 °C and react for 12 hours to obtain the polyacrylate prepolymer.

2. The ultraviolet ray-blocking optical adhesive according to claim 1, wherein The optical adhesive sequentially includes a first release film, a first adhesive layer, a hardening layer, a substrate, and a second adhesive layer.

3. The ultraviolet-blocking optical adhesive according to claim 1, wherein The optical adhesive sequentially includes a first release film, a first adhesive layer, a hardening layer, a substrate, a second adhesive layer, and a second release film.

4. The ultraviolet ray-blocking optical adhesive according to claim 1, wherein The 25-27 parts by weight of the solvent includes 13-15 parts by weight of methyl ethyl ketone as the solvent and 10-12 parts by weight of propylene glycol monomethyl ether as the solvent.

5. The ultraviolet ray-blocking optical adhesive according to claim 1, wherein The 30 parts by weight of the solvent includes 15 parts by weight of toluene as the solvent and 15 parts by weight of ethyl acetate as the solvent.

6. The ultraviolet ray blocking optical adhesive according to claim 1, wherein The substrate is a TPU film, the thickness of the substrate is 25-35 μm, the thickness of the hardening layer is 1 μm, the thickness of the first adhesive layer is 10 μm, and the thickness of the second adhesive layer is 10 μm.

7. A method for preparing the ultraviolet light-blocking optical adhesive according to any one of claims 1-6, characterized in that, The method includes the following steps: (1) Coat the hardening layer coating solution on one side of the substrate, dry the formed coating at 80-90 °C for 4 minutes, and then cure the dried coating by ultraviolet rays of a high-pressure mercury lamp to obtain the hardening layer; (2) Coat a layer of optical adhesive coating solution on the second release film, heat the formed coating at 100-120 °C for 4 minutes to obtain the second adhesive layer; (3) Coat a layer of optical adhesive coating solution on the above hardening layer, heat the formed coating at 100-120 °C for 4 minutes to obtain the first adhesive layer; (4) Bond the second adhesive layer to the untreated surface of the substrate to obtain the final product.

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