Polaroid creep adhesive suitable for IPS curved display screen

Abstract

The invention relates to a polaroid creep adhesive suitable for an IPS curved display screen. The polaroid creep adhesive is prepared from the following components in parts by weight: 50-70 parts of acrylic resin, 0.01-0.5 part of an initiator, 150 parts of ethyl acetate, 0.01-0.5 part of a curing agent, 0.01-0.5 part of a silane coupling agent and 0.1-0.5 part of a metal catalyst. The invention further relates to an IPS curved display screen which comprises panel glass, a first polaroid arranged on the CF side of the panel glass and a second polaroid arranged on the TFT side of the panel glass, and the first polaroid and the second polaroid are both attached to the panel glass through the creep adhesive. The IPS curved display screen designed by the invention has an extremely low warping rate after passing through a high-temperature and high-humidity environment, the panel glass is not easy to warp, and the risk of light leakage at four corners of the display screen is reduced. The creep adhesive designed by the invention has very high stability and adhesive force, and the polaroid is not easy to fall off when being attached to panel glass.

Description

Technical Field

[0001] This invention relates to the field of display panels, and more particularly to a polarizer creep adhesive suitable for IPS curved displays. Background Technology

[0002] Curved screen technology was first applied in the television industry, and its design was inspired by the natural curve of the human eye. As the technology matured and costs decreased, curved screens gradually moved from the high-end market to the mass market, becoming a standard feature in many monitors and television products.

[0003] Currently, most monitor panels on the market are divided into two types: IPS and VA. Curved screens commonly use VA display panels. The biggest advantages of VA panels are that they do not leak light, have obvious contrast advantages, and have a good sense of depth, making the picture more impactful. However, the disadvantages are quite fatal for gamers. In recent years, with the popularity of high refresh rate e-sports, VA monitors have a slow response speed, and the ghosting is obvious when playing FPS games. Therefore, the disadvantages outweigh the advantages when applied to curved e-sports monitors.

[0004] Another type of display panel, IPS technology, is rapidly evolving. LG's Nano IPS and AUO's Fast IPS display panels generally boast high response times and color clarity. However, when used in curved displays, they exhibit light leakage at the four corners. This is a natural characteristic of IPS displays, not an abnormal phenomenon. This light leakage becomes more pronounced after prolonged exposure to high temperatures or high-temperature, high-humidity environments. This is due to the influence of temperature and humidity, causing the panel glass to bend and warp (cell bending). The uneven shrinkage of the upper and lower polarizers attached to the glass substrate results in severe light leakage at the four corners, impacting the user experience. Currently, this light leakage cannot be completely eliminated technically. Summary of the Invention

[0005] The purpose of this invention is to solve the problem of light leakage caused by edge warping of IPS curved screens in high temperature and high humidity environments.

[0006] On the one hand, this application provides a polarizer creep adhesive suitable for IPS curved displays, which is made of the following components by weight: 50-70 parts of acrylic resin, 0.01-0.5 parts of initiator, 150 parts of ethyl acetate, 0.01-0.5 parts of curing agent, 0.01-0.5 parts of silane coupling agent, and 0.1-0.5 parts of metal catalyst.

[0007] More specifically, the acrylic resin is selected from any one or more of butyl acrylate, isooctyl acrylate, lauryl acrylate, n-octyl acrylate, methyl acrylate, acrylamide, and hydroxyethyl acrylate.

[0008] More specifically, the initiator is selected from any one or more of azobisisobutyronitrile, benzoyl peroxide, azobisisoheptanenitrile, and sodium persulfate.

[0009] More specifically, the curing agent is selected from any one or more of hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), and toluene diisocyanate (TDI). More specifically, the silane coupling agent is a multifunctional silane coupling agent, selected from any one or more of propyltriethoxysilane, 3-glycidyl etheroxypropyltrimethoxysilane, and 3-epoxypropoxypropyltrimethoxysilane.

[0010] More specifically, the metal catalyst is selected from one or more of the following: dibutyltin dilaurate (DBTDL), stannous octoate, dibutyltin diacetate (DBTDA), dibutyltin dimaleate (DBTML), dibutyltin Bis(acetylacetonate), aluminum acetylacetonate (Al(acac)3), triethylaluminum (TEA), aluminum isopropoxide, and aluminum naphthenate.

[0011] More specifically, the creep adhesive has an elastic modulus of 50,000 to 100,000 Pa, a gel fraction of 45 to 80%, and a weight-average molecular weight of 600,000 to 900,000.

[0012] More specifically, the adhesion between the first polarizer and the second polarizer and the panel glass is 150~500gf / 25mm.

[0013] Secondly, this application provides an IPS curved display screen, including a panel glass, a first polarizer disposed on the CF side of the panel glass, and a second polarizer disposed on the TFT side of the panel glass. Both the first polarizer and the second polarizer are bonded to the panel glass by the creep adhesive described in claims 1 to 7. The first polarizer includes a PVA polarizing film, a first compensation film disposed on the side of the PVA polarizing film near the panel glass, and a first protective film disposed on the side of the PVA polarizing film away from the panel glass. The second polarizer includes a PVA polarizing film, a second compensation film disposed on the side of the PVA polarizing film near the panel glass, and a second protective film disposed on the side of the PVA polarizing film away from the panel glass.

[0014] More specifically, the first protective film is selected from either PET film or PMMA film, the second protective film is selected from either PET film or PMMA film, the first compensation film is selected from either TAC film or PMMA film, and the second compensation film is selected from either TAC film or PMMA film.

[0015] More specifically, the first protective film is a PET film, the first compensation film is a PMMA film, the second protective film is a PMMA film, and the second compensation film is a PMMA film.

[0016] The beneficial effects of this invention are: The IPS curved display screen designed in this application exhibits lower warpage under high temperature and high humidity conditions. Using the creep adhesive designed in this application, a first polarizing film with a first protective film of PET and a first compensation film of PMMA is adhered to the CF side of the panel glass, and a second polarizing film with a second protective film of PMMA and a second compensation film of PMMA is adhered to the TFT side of the panel glass. This polarizing film combination enables the IPS curved display screen to exhibit minimal warpage under high temperature and high humidity conditions, greatly preventing light leakage at the four corners of the curved display screen.

[0017] The creep adhesive designed in this application exhibits significantly higher stability and adhesion compared to traditional pressure-sensitive adhesives, making it less prone to detachment when bonding the polarizer to the panel glass. Furthermore, the formulation incorporates a metal catalyst. On one hand, the empty orbitals of transition metal particles form coordinate bonds with the oxygen / nitrogen groups (hydroxyl -OH, carboxyl -COOH, isocyanate -NCO) or electrons in unsaturated bonds in the reaction system, significantly lowering the activation energy and greatly increasing the reaction rate. On the other hand, the metal particles are highly dispersed at the molecular level within the polymer matrix, forming a planar conductive network and reducing the surface resistance of the creep adhesive, thus achieving antistatic effects without the need for additional antistatic agents. When the panel glass is powered on, the increased temperature can cause thermal stress and deterioration of the polymer polarizer. The metal catalyst in the creep adhesive of this application can also conduct away some of the heat, reducing the impact of thermal stress and extending the lifespan of the polarizer and the panel glass. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of light leakage in an existing IPS display panel; Figure 2 This is a map of the bending test sites in this application. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the specific embodiments of this invention are described clearly and completely below. Obviously, the described embodiments are only a part of the embodiments of this invention, not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0020] Preparation of creep adhesive: Acrylic resin monomers and initiators are solution polymerized together in a reaction vessel equipped with temperature control, stirring, and condensation functions. The mixture is first stirred for 1 hour at 23°C under a nitrogen atmosphere, followed by nitrogen purging. The reaction is then stirred at 70°C for 4 hours. The reaction solution is then heated to 100°C to remove unreacted monomers, resulting in a pre-polymerized adhesive with a viscosity of 15,000–20,000 cps and a solid content of 30–40%. This pre-polymerized adhesive is unsuitable for polarizing film applications. Firstly, its viscosity is too high for coating; secondly, it lacks sufficient holding power and weather resistance for glass bonding. Therefore, the pre-polymerized adhesive needs to be diluted with ethyl acetate to a viscosity of 3,000–5,000 cps and a solid content of 15–25%.

[0021] Take the original adhesive, curing agent, silane coupling agent, metal catalyst, and ethyl acetate and stir at 200 r / min for 1 hour to form the finished creep adhesive coating solution. Use an automatic coating machine to uniformly coat the creep adhesive with a thickness of 140 μm on the release film. Remove the solvent at a high temperature of 80 degrees Celsius to obtain the adhesive film for use in polarizing film. Then, use a laminating machine to attach the adhesive film to one side of the polarizing film compensation film.

[0022] The specific formulations of the creep adhesives used in the following examples and comparative examples are shown in the table below:

[0023] Example 1 S1: The first protective film of the first polarizer on the CF side is made of AG-PET (film manufacturer: TOYOBY), and the first compensation film is made of PMMA (film manufacturer: TK); the second protective film of the second polarizer on the TFT side is made of PMMA (film manufacturer: TK), and the second compensation film is made of PMMA (film manufacturer: TK).

[0024] S2: The first polarizer is attached to the CF side of the BOE-65 inch panel glass using creep adhesive, and the second polarizer is attached to the TFT side of the BOE-65 inch panel glass. The two polarizers are then placed in a pressure vessel for degassing under pressure (conditions set: 50℃, 5KG, 20min).

[0025] S3: Take out the sample to be tested and place it on a flat experimental table. Use a wedge gauge to measure the height of the edge of the panel glass, i.e., the cell bending value. Measure and record the values ​​when the CF side is facing up in Table 1.

[0026] S4: Immerse the panel glass in an environmental chamber for a period of time (environmental chamber parameters set: 60℃ / 90%RH, 500H). After the period of time, perform cell bending measurement again and record the data in Table 2 (measurement method is the same as S3).

[0027] Example 2 S1: The first protective film of the first polarizer on the CF side is made of AG-PET (film manufacturer: TOYOBY), and the first compensation film is made of 0 TAC (film manufacturer: Fuji); the second protective film of the second polarizer on the TFT side is made of PET (film manufacturer: TOYOBY), and the second compensation film is made of 0 TAC (film manufacturer: Fuji).

[0028] S2: The first polarizer is attached to the CF side of the BOE-65 inch panel glass using creep adhesive, and the second polarizer is attached to the TFT side of the BOE-65 inch panel glass. The two polarizers are then placed in a pressure vessel for degassing under pressure (conditions set: 50℃, 5KG, 20min).

[0029] S3: Take out the sample to be tested and place it on a flat experimental table. Use a wedge gauge to measure the height of the edge of the panel glass, i.e., the cell bending value. Measure and record the values ​​when the CF side is facing up in Table 1.

[0030] S4: Immerse the panel glass in an environmental chamber for a period of time (environmental chamber parameters set: 60℃ / 90%RH, 500H). After the period of time, perform cell bending measurement again and record the data in Table 2 (measurement method is the same as S3).

[0031] Example 3 S1: The first protective film of the first polarizer on the CF side is made of AG-PET (film manufacturer: TOYOBY), and the first compensation film is made of PMMA (film manufacturer: TK); the second protective film of the second polarizer on the TFT side is made of PMMA (film manufacturer: TK), and the second compensation film is made of PMMA (TK).

[0032] S2: The first polarizer is attached to the CF side of the BOE-65 inch panel glass using creep adhesive, and the second polarizer is attached to the TFT side of the BOE-65 inch panel glass. The two polarizers are then placed in a pressure vessel for degassing under pressure (conditions set: 50℃, 5KG, 20min).

[0033] S3: Take out the sample to be tested and place it on a flat experimental table. Use a wedge gauge to measure the height of the edge of the panel glass, i.e., the cell bending value. Measure and record the values ​​when the CF side is facing up in Table 1.

[0034] S4: Immerse the panel glass in an environmental chamber for a period of time (environmental chamber parameters set: 60℃ / 90%RH, 500H). After the period of time, perform cell bending measurement again and record the data in Table 2 (measurement method is the same as S3).

[0035] Example 4 S1: The first protective film of the first polarizer on the CF side is made of AG-PET (film manufacturer: TOYOBY), and the first compensation film is made of PMMA (film manufacturer: TK); the second protective film of the second polarizer on the TFT side is made of PMMA (film manufacturer: TK), and the second compensation film is made of PMMA (film manufacturer: TK).

[0036] S2: The first polarizer is attached to the CF side of the BOE-65 inch panel glass using creep adhesive, and the second polarizer is attached to the TFT side of the BOE-65 inch panel glass. The two polarizers are then placed in a pressure vessel for degassing under pressure (conditions set: 50℃, 5KG, 20min).

[0037] S3: Take out the sample to be tested and place it on a flat experimental table. Use a wedge gauge to measure the height of the edge of the panel glass, i.e., the cell bending value. Measure and record the values ​​when the CF side is facing up in Table 1.

[0038] S4: Immerse the panel glass in an environmental chamber for a period of time (environmental chamber parameters set: 60℃ / 90%RH, 500H). After the period of time, perform cell bending measurement again and record the data in Table 2 (measurement method is the same as S3).

[0039] Example 5 S1: The first protective film of the first polarizer on the CF side is made of AG-PET (film manufacturer: TOYOBY), and the first compensation film is made of PMMA (film manufacturer: TK); the second protective film of the second polarizer on the TFT side is made of PMMA (film manufacturer: TK), and the second compensation film is made of PMMA (film manufacturer: TK).

[0040] S2: The first polarizer is attached to the CF side of the BOE-65 inch panel glass using creep adhesive, and the second polarizer is attached to the TFT side of the BOE-65 inch panel glass. The two polarizers are then placed in a pressure vessel for degassing under pressure (conditions set: 50℃, 5KG, 20min).

[0041] S3: Take out the sample to be tested and place it on a flat experimental table. Use a wedge gauge to measure the height of the edge of the panel glass, i.e., the cell bending value. Measure and record the values ​​when the CF side is facing up in Table 1.

[0042] S4: Immerse the panel glass in an environmental chamber for a period of time (environmental chamber parameters set: 60℃ / 90%RH, 500H). After the period of time, perform cell bending measurement again and record the data in Table 2 (measurement method is the same as S3).

[0043] Comparative Example 1 S1: The first protective film of the first polarizer on the CF side is made of PET (film manufacturer: TOYOBY), and the first compensation film is made of PMMA (film manufacturer: TK); the second protective film of the second polarizer on the TFT side is made of PMMA (film manufacturer: TK), and the second compensation film is made of PMMA (film manufacturer: TK).

[0044] S2: The first polarizer is attached to the CF side of the BOE-65 inch panel glass using creep adhesive, and the second polarizer is attached to the TFT side of the BOE-65 inch panel glass. The two polarizers are then placed in a pressure vessel for degassing under pressure (conditions set: 50℃, 5KG, 20min).

[0045] S3: Take out the sample to be tested and place it on a flat experimental table. Use a wedge gauge to measure the height of the edge of the panel glass, i.e., the cell bending value. Measure and record the values ​​when the CF side is facing up in Table 1.

[0046] S4: Immerse the panel glass in an environmental chamber for a period of time (environmental chamber parameters set: 60℃ / 90%RH, 500H). After the period of time, perform cell bending measurement again and record the data in Table 2 (measurement method is the same as S3).

[0047] Comparative Example 2 S1: The first protective film of the first polarizer on the CF side is made of AG-PET (film manufacturer: TOYOBY), and the first compensation film is made of OTAC (film manufacturer: Fuji); the second protective film of the second polarizer on the TFT side is made of PET (film manufacturer: Fuji), and the second compensation film is made of OTAC (film manufacturer: Fuji).

[0048] S2: The first polarizer is attached to the CF side of the BOE-65 inch panel glass using creep adhesive, and the second polarizer is attached to the TFT side of the BOE-65 inch panel glass. The two polarizers are then placed in a pressure vessel for degassing under pressure (conditions set: 50℃, 5KG, 20min).

[0049] S3: Take out the sample to be tested and place it on a flat experimental table. Use a wedge gauge to measure the height of the edge of the panel glass, i.e., the cell bending value. Measure and record the values ​​when the CF side is facing up in Table 1.

[0050] S4: Immerse the panel glass in an environmental chamber for a period of time (environmental chamber parameters set: 60℃ / 90%RH, 500H). After the period of time, perform cell bending measurement again and record the data in Table 2 (measurement method is the same as S3).

[0051] Comparative Example 3 S1: The first protective film of the first polarizer on the CF side is made of AG-PET (film manufacturer: TOYOBY), and the first compensation film is made of PMMA (film manufacturer: TK); the second protective film of the second polarizer on the TFT side is made of PMMA (film manufacturer: TK), and the second compensation film is made of PMMA (film manufacturer: TK).

[0052] S2: The first polarizer is attached to the CF side of the BOE-65 inch panel glass using creep adhesive, and the second polarizer is attached to the TFT side of the BOE-65 inch panel glass. The two polarizers are then placed in a pressure vessel for degassing under pressure (conditions set: 50℃, 5KG, 20min).

[0053] S3: Take out the sample to be tested and place it on a flat experimental table. Use a wedge gauge to measure the height of the edge of the panel glass, i.e., the cell bending value. Measure and record the values ​​when the CF side is facing up in Table 1.

[0054] S4: Immerse the panel glass in an environmental chamber for a period of time (environmental chamber parameters set: 60℃ / 90%RH, 500H). After the period of time, perform cell bending measurement again and record the data in Table 2 (measurement method is the same as S3).

[0055] Table 1. 0H Cell bending test data

[0056] Table 2. Cell bending test data at 60℃ / 90%RH for 500 hours

[0057] The data in Tables 1 and 2 that need to be supplemented are: 1. Measuring feeler gauge: Mitutoyo brand from Japan, model and specifications: 0.02mm~3mm; II. Glass Panel Orientation: This indicates that when using a feeler gauge to measure cell bending, the panel should be flat with the CF side facing upwards. The eight measurement points are as follows: Figure 2 The four corners and center points of the four sides of the panel glass shown; From Table 1, the Cell bending test data at 0H, it can be seen that the Cell bending values ​​of Examples 1-5 and Comparative Examples 1-3 are all between 0 and 0.3 mm. From Table 2, the Cell bending test data at 60℃ / 90%RH at 500H, it can be seen that the bending values ​​of measuring points 1, 2, 3, 5, 6, and 7 of Cell Example 1 are the highest, indicating that Example 1 has the best performance.

[0058] The creep adhesives and glass panels used in the above embodiments and comparative examples were subjected to tests on basic physical properties, weather resistance, and display mura performance. The test results are as follows:

[0059] The performance testing methods in the table above are as follows: (1) Elastic modulus test: The above adhesive was coated into a 20um NCF (with adhesive in the middle of the double-layer release film), and the elastic modulus was tested using an E-4000 viscoelasticity tester.

[0060] (2) Surface impedance: The surface impedance was tested using an MCP-HT800 (Mitsubishi) surface impedance meter at a voltage of 500V.

[0061] (3) Gel fraction test: Weigh A g of glue from NCF, weigh B g of 200-mesh filter screen, put A g of glue into 20 g of ethyl acetate and let it stand for 12 hours, shake for 15 minutes, then pour the mixture into the filter screen and let it stand for 30 minutes before drying in an oven to obtain the total weight C. Gel fraction = (CB) * 100% / A (4) Heat resistance, moisture resistance, and thermal shock resistance: The acrylic resin pressure-sensitive adhesive prepared above was coated onto the release film, then bonded to the polarizing plate, dried, and left at room temperature for 7 days. The polarizing plate was then cut into small-sized polarizing plates of 150*170mm and bonded to glass to prepare samples. The samples were placed in high temperature (80℃), high temperature and high humidity (60℃, 90% humidity), and thermal shock (temperature from -35℃ to +80℃) environments for 240 hours for evaluation.

[0062] The evaluation criteria are as follows: ◎It neither bubbles nor peels off; Occasionally, blistering or peeling may occur; △ Slight blistering or peeling; ╳ Bubbling or peeling.

[0063] (5) Light leakage condition: The polarizing plates prepared above are bonded together, dried, and placed at room temperature for 7 days. The polarizing plates are then cut into 65-inch standard TV polarizing plates and attached to the 65-inch panel. The light leakage condition at the edge is observed under backlight.

[0064] The evaluation criteria are as follows: ◎No light leakage; Occasionally, light leakage occurs; △ Slight light leakage; ╳ Severe light leakage.

[0065] Based on the above performance test results, it can be concluded that Example 1 (upper polarizer PET / PMMA, lower polarizer PMMA / PMMA paired with BOE-65 inch) exhibits a high cell bending value, good weather resistance, meets the requirements for antistatic properties, and has excellent mura effect. It can be confirmed that this polarizer assembly, when paired with self-made creep soft rubber, is suitable for IPS curved displays.

[0066] The embodiments of the present invention have been described in detail above, but the present invention is not limited to the described embodiments. For those skilled in the art, various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and these variations still fall within the protection scope of the present invention.

Claims

1. A polarizing sheet creep adhesive suitable for an IPS curved display screen, characterized by, The acrylic resin is selected from any one or several of butyl acrylate, isooctyl acrylate, lauryl acrylate, n-octyl acrylate, methyl acrylate, acrylamide, hydroxyethyl acrylate.

2. The creep adhesive according to claim 1, characterized in that The initiator is selected from any one or several of azobisisobutyronitrile, benzoyl peroxide, azobisisoheptyl nitrile, sodium persulfate.

3. The creep adhesive of claim 1, wherein, The curing agent is selected from any one or several of toluene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate.

4. The creep adhesive of claim 1, wherein, The silane coupling agent is a multifunctional silane coupling agent, selected from any one or several of propyl triethoxysilane, 3-glycidyl ether oxypropyl trimethoxysilane, 3-epoxypropoxypropyl trimethoxysilane.

5. The creep adhesive of claim 1, wherein, The metal catalyst is selected from one or several of dibutyl tin dilaurate, stannous octoate, dibutyl tin diacetate, dibutyl tin dimaleate, dibutyl tin bis(acetylacetate), aluminum acetylacetonate, triethyl aluminum, aluminum isopropoxide, aluminum naphthenate.

6. The creep adhesive of claim 1, wherein, The creep adhesive has an elastic modulus of 50000-100000 pa, a gel fraction of 45-80%, and a weight average molecular weight of 600,000-900,000.

7. The creep adhesive according to any one of claims 2 to 6, wherein The first polarizing sheet and the second polarizing sheet are both attached to the panel glass by the creep adhesive according to claims 1-7; the first polarizing sheet comprises a PVA polarizing film, a first compensation film disposed on the side of the PVA polarizing film close to the panel glass, and a first protective film disposed on the side of the PVA polarizing film away from the panel glass; the second polarizing sheet comprises a PVA polarizing film, a second compensation film disposed on the side of the PVA polarizing film close to the panel glass, and a second protective film disposed on the side of the PVA polarizing film away from the panel glass.

8. An IPS curved display screen, characterized by, The first protective film is selected from any one of a PET film and a PMMA film, the second protective film is selected from any one of a PET film and a PMMA film, the first compensation film is selected from any one of a TAC film and a PMMA film, and the second compensation film is selected from any one of a TAC film and a PMMA film.

9. The IPS curved display screen according to claim 8, wherein, The first protective film is a PET film, the first compensation film is a PMMA film, the second protective film is a PMMA film, and the second compensation film is a PMMA film.

10. The IPS curved display screen according to claim 9, wherein, ​

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