Water-based primer coating liquid, PMMA (polymethyl methacrylate) base film and preparation method

Abstract

The invention provides a water-based primer coating liquid which is used for a PMMA (polymethyl methacrylate) base film for a polaroid and comprises the following components: 2-6 parts of polyurethane resin, 1-6 parts of acrylate resin, 2-8 parts of a cross-linking agent, 1-6 parts of silicon dioxide particles and 95-110 parts of pure water. According to the coating liquid designed by the invention, the polyurethane resin and the acrylate resin are mixed to serve as matrix resin, the primer layer has excellent surface wear resistance by adjusting the ratio of the polyurethane resin to the acrylate resin, the transmittance of a base film is improved, and meanwhile, the adhesiveness with UV glue is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of optical materials, and in particular relates to a water-based primer coating liquid, a PMMA base film and a preparation method thereof. Background Art

[0002] Polaroid, as a key component of display module imaging, has a complex structure and important functions. It is mainly composed of PVA film, upper and lower substrates, protective film, release film and pressure-sensitive adhesive. Two sheets are required in the LCD module, placed on both sides of the glass substrate. The lower polarizer is responsible for converting the backlight beam into polarized light, while the upper polarizer analyzes the polarized light after liquid crystal electrical modulation. Both are indispensable to ensure the normal display of the picture. Among them, the polarizers obtained after the PVA film is stretched are the core part of the polarizer, but due to its fragile nature, they must be protected.

[0003] PMMA film, or polymethyl methacrylate film, has become the preferred material for polarizing plate protective film due to its stability, moisture impermeability, excellent weather resistance, high transmittance and good light transmission performance. However, the direct bonding of PMMA film and polarizer has the problem of poor bonding, which affects the overall performance and stability of the polarizer. It is usually necessary to apply a layer of coating liquid that is conducive to bonding on the bonding surface of the PMMA original film. In addition to increasing the adhesion between the glue and the PMMA original film, the coating liquid can also prevent the PMMA base film from sticking to each other after it is rolled up.

[0004] However, as the panel industry pursues higher quality, in order to meet the production needs of polarizing plates used in high-end panels, polarizing plate manufacturers are paying more and more attention to the performance improvement of protecting polarizing film materials. The low adhesion and wear resistance of PMMA base film obtained by using traditional coating liquid can no longer meet the needs of high-end panels. Therefore, it is very urgent to improve the wear resistance of PMMA base film and the adhesion between PMMA base film and polarizing film. Summary of the invention

[0005] The purpose of the present invention is to solve the problem of laminating PMMA film and polarizer in the prior art, reduce production costs, and improve the overall performance and stability of polarizers.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] The present application provides an aqueous primer coating solution, comprising the following components in parts by weight:

[0008] 2-6 parts of polyurethane resin;

[0009] 1 to 6 parts of acrylate resin;

[0010] 2 to 8 parts of cross-linking agent;

[0011] 1 to 6 parts of silicon dioxide particles;

[0012] 95-110 parts of pure water;

[0013] The polyurethane resin is a water-based polyurethane resin, which is a polymer having a hydroxyl group or a tertiary amine group formed by the reaction of polyester polyol and isocyanate;

[0014] The acrylic ester resin is formed by the reaction of polycaprolactone and acrylic ester.

[0015] The main resin is a two-component mixture of polyurethane resin and acrylate resin.

[0016] As a further improvement of the present application, the polyurethane resin is formed by the polyreaction of 5-amino-1,3,3-trimethyl-cyclohexylmethylamine with Α-hydrogen-Ω-hydroxy-poly(oxy-1,4-butylene) and 5-isocyanato-1-(isocyanatomethyl)-1,3,3-trimethylcyclohexane.

[0017] As a further improvement of the present application, the acrylate is a polymer comprising acrylic acid, methacrylic acid and derivatives thereof. Preferably, the acrylate is selected from one or more of acrylic acid, methacrylic acid, methyl methacrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, hydroxy acrylate and polycaprolactone acrylate.

[0018] As a further improvement of the present application, the cross-linking agent is selected from one or more of oxazoline, acrylamide, and carbodiimide.

[0019] As a further improvement of the present application, the particle size of the silicon dioxide particles is 30 to 100 nm.

[0020] As a further improvement of the present application, the pure water is sterilized by ultraviolet light at 180 to 254 nm, and the resistivity of the pure water is 12 to 18 MΩ·cm.

[0021] To achieve the above object, the present application also provides a method for preparing the above-mentioned aqueous primer coating solution, comprising the following steps:

[0022] S1, adding polyurethane resin and acrylate resin into a reaction container in sequence according to a preset ratio, and stirring at a speed of 200 rpm to 500 rpm for 20 min to 60 min to obtain a first mixed solution;

[0023] S2, adding a cross-linking agent to the first mixed solution according to a preset ratio, and stirring at a speed of 250 rpm to 550 rpm for 20 min to 60 min to obtain a second mixed solution;

[0024] S3. Add silica particles and pure water to the second mixed solution in a preset ratio, stir at a speed of 200 rpm to 500 rpm for 20 min to 40 min, and after stirring evenly, circulate and filter in a filter with a pore size of 1 μm to 10 μm for 20 to 60 min. After circulating filtration, let it stand in a low pressure environment of -0.1 MPa to 0 MPa for 3 to 6 hours until the bubbles completely disappear, and obtain an aqueous primer coating liquid.

[0025] To achieve the above-mentioned purpose, the present application also provides a PMMA base film, including a PMMA original film and an aqueous primer coating liquid layer arranged on the surface of the PMMA original film, wherein the aqueous primer coating liquid layer is prepared from the aqueous primer coating liquid described above, or the aqueous primer coating liquid layer is prepared from the aqueous primer coating liquid prepared by the preparation method described above.

[0026] To achieve the above object, the present application also provides a method for preparing the above-mentioned PMMA base film, comprising the following steps: first, treating the surface of the PMMA original film with a corona treatment power of 0.1KW to 6KW, so that the contact angle of the surface of the PMMA original film is reduced to between 40° and 65°; second, uniformly coating a layer of aqueous primer coating liquid on the surface of the PMMA original film, and drying to obtain a PMMA base film;

[0027] As a further improvement of the present application, the drying temperature is 50° C. to 150° C., and the thickness of the aqueous primer coating liquid layer after drying is 200 nm to 800 nm.

[0028] As a further improvement of the present application, the coating method is selected from any one of wire rod coating, extrusion coating, and micro-concave coating.

[0029] The beneficial effect of the present application lies in that the present application provides an aqueous primer coating liquid, whose components include polyurethane resin, acrylate resin, cross-linking agent, silica particles and pure water, wherein: the polyurethane resin is an aqueous polyurethane resin, which is a polymer with hydroxyl or tertiary amine groups formed by the reaction of polyester polyol and isocyanate, and the acrylate resin is formed by the reaction of polycaprolactone and acrylate.

[0030] The coating liquid is applied between the PMMA original film and the UV adhesive. Its unique formula design not only significantly improves the surface roughness and gives the base film better surface wear resistance by optimizing the ratio of polyurethane resin to acrylate resin, thereby effectively extending the service life of the base film and improving its overall durability and reliability; moreover, the coating liquid exhibits excellent dispersion, which helps to improve the transmittance of the base film and make light transmission more efficient. More importantly, its adhesion with UV adhesive has been significantly improved, achieving a lower moisture permeability. This improvement greatly enhances the weather resistance and water resistance of the polarizer, fully meeting higher-level usage requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a cross-sectional scanning electron microscope image of the PMMA base film of the present application;

[0032] Figure 2 This is a schematic diagram of the structure of the PMMA base film of the present application;

[0033] Figure 3 This is a schematic diagram of the structure of the polarizer of this application.

[0034] In the figure: 1. upper protective film layer; 2. upper adhesive layer; 3. polarizing film layer; 4. lower adhesive layer; 5. lower protective film layer. DETAILED DESCRIPTION

[0035] The present invention is further described below. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and are not intended to limit the protection scope of the present invention.

[0036] In order to overcome the shortcomings of the prior art, the present invention provides a coating liquid formulation, comprising the following components in parts by weight:

[0037] 2-6 parts of polyurethane resin;

[0038] 1 to 6 parts of acrylate resin;

[0039] 2 to 8 parts of cross-linking agent;

[0040] 1 to 6 parts of silicon dioxide particles;

[0041] 95-110 parts of pure water;

[0042] Wherein: the polyurethane resin is a water-based polyurethane resin, a polymer with hydroxyl or tertiary amine groups formed by the reaction of polyester polyol and isocyanate, and the acrylate resin is formed by the reaction of polycaprolactone and acrylate. The main resin selected in the application is a mixture of water-based polyurethane resin and acrylate resin. The hydroxyl contained in the water-based polyurethane resin selected for the polyurethane resin enhances its solubility in water; the acrylate selects polycaprolactone acrylate, which contains carboxyl groups with good adhesion to the original PMMA film. Water-based polyurethane resin has good flexibility, solvent resistance, and high temperature resistance, and acrylate resin has good weather resistance, friction resistance, high permeability, adhesion and other advantages. The acrylate in the main resin is grafted onto the main chain of polyurethane through a free radical grafting reaction for chain growth to form a copolymer with a molecular weight between 10,000 and 1,000,000, which can achieve sufficient adhesion and better dispersibility in water. This copolymer can combine the advantages of two resins, has good material compatibility and solvent resistance, is conducive to the formation of functional coatings, and as a main resin has good film-forming properties, transparency and adhesion, is non-flammable, non-toxic and low-volatile, is environmentally friendly, and has higher safety during production and use.

[0043] In an optional embodiment, the polyurethane resin is formed by the polymerization reaction of 5-amino-1,3,3-trimethyl-cyclohexylmethylamine with Α-hydrogen-Ω-hydroxy-poly(oxy-1,4-butylene) and 5-isocyanato-1-(isocyanatomethyl)-1,3,3-trimethylcyclohexane.

[0044] In an optional embodiment, the acrylate is a polymer comprising acrylic acid, methacrylic acid and derivatives thereof. Preferably, the acrylate is selected from one or more of acrylic acid, methacrylic acid, methyl methacrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, hydroxy acrylate and polycaprolactone acrylate.

[0045] In an optional embodiment, the cross-linking agent is selected from one or more of oxazoline, acrylamide, and carbodiimide.

[0046] In an optional embodiment, the particle size of the silicon dioxide particles is 30 to 100 nm.

[0047] In an optional embodiment, the pure water is sterilized by ultraviolet light at 180 to 254 nm, and the resistivity of the pure water is 12 to 18 MΩ·cm. The ultraviolet sterilization of the pure water avoids the introduction of bacteria into the raw material formula.

[0048] To achieve the above object, the present application also provides a method for preparing an aqueous primer coating solution, comprising the following steps:

[0049] S1, adding polyurethane resin and acrylate resin into a reaction container in sequence according to a preset ratio, and stirring at a speed of 200 rpm to 500 rpm for 20 min to 60 min to obtain a first mixed solution;

[0050] S2, adding a cross-linking agent to the first mixed solution according to a preset ratio, and stirring at a speed of 250 rpm to 550 rpm for 20 min to 60 min to obtain a second mixed solution;

[0051] S3. Add silica particles and pure water to the second mixed solution in a preset ratio, stir at a speed of 200 rpm to 500 rpm for 20 min to 40 min, and after stirring evenly, circulate and filter in a filter with a pore size of 1 μm to 10 μm for 20 to 60 min. After circulating filtration, let it stand in a low pressure environment of -0.1 MPa to 0 MPa for 3 to 6 hours until the bubbles completely disappear, and obtain an aqueous primer coating liquid.

[0052] To achieve the above-mentioned purpose, the present application also provides a PMMA base film, including a PMMA original film and an aqueous primer coating liquid layer arranged on the surface of the PMMA original film, wherein the aqueous primer coating liquid layer is prepared from the aqueous primer coating liquid described above, or the aqueous primer coating liquid layer is prepared from the aqueous primer coating liquid prepared by the preparation method described above.

[0053] To achieve the above object, the present application also provides a method for preparing the above-mentioned PMMA base film, comprising the following steps: first, treating the surface of the PMMA original film with a corona treatment power of 0.1KW to 6KW, so that the contact angle of the surface of the PMMA original film is reduced to between 40° and 65°; second, uniformly coating a layer of aqueous primer coating liquid on the surface of the PMMA original film, and drying to obtain a PMMA base film;

[0054] In an optional embodiment, the drying temperature is 50° C. to 150° C., and the thickness of the aqueous primer coating liquid layer after drying is 200 nm to 800 nm.

[0055] In an optional embodiment, the coating method is selected from any one of wire rod coating, extrusion coating, and micro-concave coating. Wire rod coating is a coating roller surface with surrounding linear protrusions, and the coating liquid can be temporarily stored between the linear protrusions when the coating roller passes through the lower liquid tank, and the coating liquid is applied to the surface of the PMMA original film when the coating roller rolls and contacts the upper PMMA original film; extrusion coating is a T-shaped extrusion port, and the liquid can be evenly applied to the surface of the PMMA original film when the PMMA original film passes; micro-concave coating is a coating roller surface with fine grooves, and the coating liquid can be temporarily stored in the grooves when the coating roller passes through the liquid tank, and the coating liquid is applied to the surface of the PMMA original film when it contacts the PMMA original film.

[0056] In order to verify that the technical solution of the present application has excellent technical effects, the following embodiments and comparative examples are also provided.

[0057] Example 1

[0058] The present embodiment provides an aqueous primer coating liquid and a preparation method thereof. The aqueous primer coating liquid comprises the following components in parts by weight: 2 parts of polyurethane resin, 1 part of acrylate resin, 2 parts of crosslinking agent, 1 part of silica particles, and 95 parts of pure water; wherein: the polyurethane resin is formed by the reaction of 5-amino-1,3,3-trimethyl-cyclohexylmethylamine with Α-hydrogen-Ω-hydroxy-poly(oxy-1,4-butylene) and 5-isocyanato-1-(isocyanatomethyl)-1,3,3-trimethylcyclohexane, and the acrylate resin is formed by the reaction of polycaprolactone and acrylate.

[0059] The preparation method of the water-based primer coating solution is as follows:

[0060] S1, adding waterborne polyurethane resin and acrylate resin into a reaction container in parts by weight, and stirring at a speed of 200 rpm for 60 minutes to obtain a first mixed solution;

[0061] S2. Add a cross-linking agent to the first mixed solution by weight, and stir at 250 rpm for 60 min to obtain a second mixed solution; wherein the cross-linking agent is oxazoline.

[0062] S3. Add silicon dioxide particles with an average particle size of 30 nm and pure water to the second mixed solution in parts by weight, stir at a speed of 200 rpm for 40 minutes, and after stirring evenly, circulate and filter in a filter with a filter element pore size of 1 μm for 60 minutes. After circulating and filtering, stand in a low pressure environment of -0.1Mpa to 0Mpa for 3 hours until the bubbles completely disappear, and obtain an aqueous primer coating liquid. Wherein: pure water is pure water with a resistivity of 12MΩ·cm after irradiation with 250nm ultraviolet light.

[0063] This embodiment also provides a PMMA base film, including a PMMA original film and an aqueous primer coating liquid layer disposed on the surface of the PMMA original film, wherein the aqueous primer coating liquid layer is prepared from the aqueous primer coating liquid prepared in this embodiment. Wherein: the PMMA base film is prepared by the following method: first, the surface of the PMMA original film is treated with a corona with a power of 1KW to reduce the contact angle of the surface of the PMMA original film to below 65°; second, a layer of aqueous primer coating liquid is uniformly coated on the surface of the PMMA original film, and dried at a temperature of 80°C to obtain a PMMA base film, wherein the thickness of the aqueous primer coating liquid layer after drying is 330nm.

[0064] Example 2

[0065] The present embodiment provides an aqueous primer coating liquid and a preparation method thereof. The aqueous primer coating liquid comprises the following components in parts by weight: 6 parts of polyurethane resin, 6 parts of acrylate resin, 8 parts of crosslinking agent, 6 parts of silica particles, and 110 parts of pure water; wherein: the polyurethane resin is formed by the reaction of 5-amino-1,3,3-trimethyl-cyclohexylmethylamine with Α-hydrogen-Ω-hydroxy-poly(oxy-1,4-butylene) and 5-isocyanato-1-(isocyanatomethyl)-1,3,3-trimethylcyclohexane, and the acrylate resin is formed by the reaction of polycaprolactone and acrylate.

[0066] The preparation method of the water-based primer coating solution is as follows:

[0067] S1, adding waterborne polyurethane resin and acrylate resin into a reaction container in parts by weight, and stirring at a speed of 500 rpm for 20 minutes to obtain a first mixed solution;

[0068] S2. Add a cross-linking agent to the first mixed solution by weight, and stir at a speed of 550 rpm for 20 minutes to obtain a second mixed solution; wherein the cross-linking agent is oxazoline.

[0069] S3, add silicon dioxide particles with an average particle size of 100nm and pure water to the second mixed solution in parts by weight, stir at a speed of 500rpm for 20min, and after stirring evenly, circulate and filter in a filter with a filter element pore size of 10μm for 20min, and after circulating and filtering, stand for 6h in a low pressure environment of -0.1Mpa to 0Mpa until the bubbles completely disappear, and obtain an aqueous primer coating liquid. Wherein: pure water is pure water with a resistivity of 18MΩ·cm after irradiation with 250nm ultraviolet light.

[0070] This embodiment also provides a PMMA base film, including a PMMA original film and an aqueous primer coating liquid layer disposed on the surface of the PMMA original film, wherein the aqueous primer coating liquid layer is prepared from the aqueous primer coating liquid prepared in this embodiment. Wherein: the PMMA base film is prepared by the following method: first, the surface of the PMMA original film is treated with a corona with a power of 6KW to reduce the contact angle of the surface of the PMMA original film to below 65°; second, a layer of aqueous primer coating liquid is uniformly coated on the surface of the PMMA original film, and dried at a temperature of 80°C to obtain a PMMA base film, wherein the thickness of the aqueous primer coating liquid layer after drying is 400nm.

[0071] Example 3

[0072] The present embodiment provides an aqueous primer coating liquid and a preparation method thereof. The aqueous primer coating liquid comprises the following components in parts by weight: 4 parts of polyurethane resin, 1 part of acrylate resin, 3 parts of crosslinking agent, 2 parts of silica particles, and 100 parts of pure water; wherein: the polyurethane resin is formed by the reaction of 5-amino-1,3,3-trimethyl-cyclohexylmethylamine with Α-hydrogen-Ω-hydroxy-poly(oxy-1,4-butylene) and 5-isocyanato-1-(isocyanatomethyl)-1,3,3-trimethylcyclohexane, and the acrylate resin is formed by the reaction of polycaprolactone and acrylate.

[0073] The preparation method of the water-based primer coating solution is as follows:

[0074] S1, adding waterborne polyurethane resin and acrylate resin into a reaction container in parts by weight, and stirring at a speed of 400 rpm for 40 minutes to obtain a first mixed solution;

[0075] S2. Add a cross-linking agent to the first mixed solution by weight, and stir at 450 rpm for 40 min to obtain a second mixed solution; wherein the cross-linking agent is oxazoline.

[0076] S3, add silica particles with an average particle size of 57nm and pure water to the second mixed solution in parts by weight, stir at 450rpm for 30min, stir evenly, circulate and filter in a filter with a filter element pore size of 5μm for 40min, and stand in a low pressure environment of -0.1Mpa to 0Mpa for 5h after circulated filtration until the bubbles completely disappear, and obtain an aqueous primer coating liquid. Wherein: pure water is pure water with a resistivity of 15MΩ·cm after irradiation with 250nm ultraviolet light.

[0077] This embodiment also provides a PMMA base film, and its cross-sectional scanning electron microscope image is as follows: Figure 1Its cross-sectional structure diagram is shown in Figure 2 As shown, it includes a PMMA original film and an aqueous primer coating layer arranged on the surface of the PMMA original film, and the aqueous primer coating layer is prepared from the aqueous primer coating liquid prepared in this embodiment. Wherein: the PMMA base film is prepared by the following method: first, the surface of the PMMA original film is treated with a corona with a power of 1KW to reduce the contact angle of the surface of the PMMA original film to below 65°; secondly, a layer of aqueous primer coating layer is uniformly coated on the surface of the PMMA original film, and dried at a temperature of 80°C to obtain a PMMA base film, wherein the thickness of the aqueous primer coating layer after drying is 330nm.

[0078] Comparative Example 1

[0079] The difference between this comparative example and Example 3 is that no acrylic resin is used in the components of the aqueous primer coating liquid, and the weight portion of the polyurethane resin is adjusted to 5 parts.

[0080] Comparative Example 2

[0081] The difference between this comparative example and Example 3 is that no crosslinking agent is added to the components of the aqueous primer coating liquid.

[0082] Comparative Example 3

[0083] The difference between this comparative example and Example 3 is that no silica particles are added to the components of the aqueous primer coating liquid.

[0084] Comparative Example 4

[0085] The difference between this comparative example and Example 3 is that a layer of aqueous primer coating liquid is directly and evenly coated on the surface of the PMMA original film without performing corona treatment.

[0086] Comparative Example 5

[0087] The difference between this comparative example and Example 3 is that no treatment is performed on the surface of the original PMMA film.

[0088] In order to verify that the technical solution of the present application has excellent technical effects, the PMMA base films prepared in the above-mentioned Examples 1-3 and Comparative Examples 1-5 are respectively prepared into polarizers, and the structure of the polarizers is as follows: Figure 3As shown, it includes a lower protective film layer, a lower adhesive layer, a polarizing film layer, an upper adhesive layer, and an upper protective film layer which are stacked in sequence. The lower protective film layer and the upper protective film layer in the present application are both made of PMMA base film, and the aqueous primer coating liquid layer is close to the adhesive layer. The upper adhesive layer and the lower adhesive layer of the present application are both prepared by UV adhesive, and the UV adhesive is a free radical and cationic mixed UV adhesive. The performance of the PMMA base film and polarizer prepared above is tested.

[0089] Pencil hardness is divided into 13 levels, from hard to soft, 6H, 5H~H, HB, B, 2B~6B. The test method is as follows:

[0090] Step S1, use a pencil hardness tester to test, cut a test piece of 5cm*15cm in size, place the test piece upward and fix it on the test machine, use a pencil at a 45° angle to the test piece, and draw a 10mm mark in front of the test piece at a speed of 5mm / s. After drawing once, grind the tip of the lead core, and repeat 5 times.

[0091] Step S2, observe the five marks on the test piece, if the primer layer of the PMMA base film is damaged by more than two marks, it is judged as unqualified, if two marks are damaged or less, it is judged as qualified. A higher grade of pencil hardness is preferred.

[0092] Transmittance: A transmittance value of 90% or above is considered acceptable, and a higher value is preferred.

[0093] Peel force: A value of 128 gf / 15 mm or more is considered acceptable, and a higher value is preferred.

[0094] The performance test data is shown in Table 1.

[0095] Table 1: Performance test data of polarizers corresponding to Examples 1-3 and Comparative Examples 1-5

[0096]

[0097] It can be seen from the pencil hardness, transmittance and peel force test results of Examples 1-3 and Comparative Examples 1-5 that the coating liquid designed in the present application adds acrylate to the resin and controls the ratio of water-based polyurethane to acrylate in the main resin to increase the pencil hardness and transmittance of the PMMA base film, and the bonding ability is improved after bonding with the UV adhesive layer.

[0098] Compared with Comparative Example 1, Example 3 shows that the pencil hardness and transmittance of the PMMA base film are improved after adding the acrylate resin to the main resin, compared with the main resin using the traditional single waterborne polyurethane resin component. The hydrophobic polarizer of PMMA base film + polarizer + PMMA base film is also used, and the adhesion to the UV adhesive layer is improved.

[0099] Compared with Comparative Example 2, Example 3 shows that the adhesion to the UV adhesive layer is improved after the cross-linking agent is added.

[0100] Compared with Comparative Example 3, Example 3 shows that the addition of silicon dioxide particles prevents PMMA base films from sticking to each other.

[0101] Compared with Comparative Example 4, Example 3 shows that the adhesion between the PMMA original film and the UV adhesive layer is improved after the corona treatment.

[0102] Compared with Comparative Example 5, after coating the surface of the PMMA original film with a layer of water-based primer, the pencil hardness of the PMMA base film is increased and the adhesion to the UV adhesive layer is improved, thereby preventing PMMA base films from sticking to each other.

[0103] In summary, the main resin in the aqueous coating liquid formula designed in this application is a mixture of polyurethane resin and acrylate resin. This mixed resin has good film-forming properties and adhesion, can effectively improve the wear resistance of the primer layer and the adhesion between the PMMA base film and the PVA film, prevent the polarizer from delamination; at the same time, improve the transmittance of the base film.

[0104] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A water-based primer coating solution, characterized in that: The composition comprises the following components in parts by weight: 2-6 parts of polyurethane resin; 1 to 6 parts of acrylate resin; 2 to 8 parts of cross-linking agent; 1 to 6 parts of silicon dioxide particles; 95-110 parts of pure water; The polyurethane resin is a water-based polyurethane resin, which is a polymer having a hydroxyl group or a tertiary amine group formed by the reaction of polyester polyol and isocyanate; The acrylic ester resin is prepared by the reaction of polycaprolactone and acrylic ester.

2. The aqueous primer coating solution according to claim 1, characterized in that: The polyurethane resin is prepared by the polyreaction of 5-amino-1,3,3-trimethyl-cyclohexylmethylamine, Α-hydrogen-Ω-hydroxy-poly(oxy-1,4-butylene) and 5-isocyanato-1-(isocyanatomethyl)-1,3,3-trimethylcyclohexane.

3. The aqueous primer coating solution according to claim 2, characterized in that: The acrylate is a polymer comprising acrylic acid, methacrylic acid and their derivatives.

4. The aqueous primer coating solution according to claim 1, characterized in that: The acrylate is one or more of acrylic acid, methacrylic acid, methyl methacrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, hydroxy acrylate, and polycaprolactone acrylate.

5. The aqueous primer coating solution according to claim 1, characterized in that: The cross-linking agent is selected from one or more of oxazoline, acrylamide and carbodiimide.

6. The aqueous primer coating solution according to claim 1, characterized in that: The particle size of the silicon dioxide particles is 20 to 110 nm.

7. A method for preparing the aqueous primer coating solution according to any one of claims 1 to 6, characterized in that: The steps include: S1, adding polyurethane resin and acrylate resin into a reaction container in sequence according to a preset ratio, and stirring at a speed of 200 rpm to 500 rpm for 20 min to 60 min to obtain a first mixed solution; S2, adding a cross-linking agent to the first mixed solution according to a preset ratio, and stirring at a speed of 250 rpm to 550 rpm for 20 min to 60 min to obtain a second mixed solution; S3. Add silica particles and pure water to the second mixed solution in a preset ratio, stir at a speed of 200 rpm to 500 rpm for 20 min to 40 min, and after stirring evenly, circulate and filter in a filter with a pore size of 1 μm to 10 μm for 20 to 60 min. After circulating filtration, let it stand in a low pressure environment of -0.1 MPa to 0 MPa for 3 to 6 hours until the bubbles completely disappear, and obtain an aqueous primer coating liquid.

8. A PMMA base film, characterized in that: It comprises a PMMA original film and an aqueous primer coating liquid layer arranged on the surface of the PMMA original film, wherein the aqueous primer coating liquid layer is prepared by the aqueous primer coating liquid described in any one of claims 1 to 6, or the aqueous primer coating liquid layer is prepared by the aqueous primer coating liquid prepared by the preparation method described in claim 7.

9. A method for preparing the PMMA base film according to claim 8, characterized in that: The method comprises the following steps: firstly, treating the surface of the PMMA original film with a corona treatment power of 0.1KW to 6KW to reduce the contact angle of the surface of the PMMA original film to between 40° and 65°; secondly, uniformly coating a layer of water-based primer coating liquid on the surface of the PMMA original film, and drying the layer at a temperature of 50° to 150° to obtain a PMMA base film, wherein the thickness of the water-based primer coating liquid after drying is 200nm to 800nm.

10. The method for preparing a PMMA base film according to claim 9, characterized in that: The coating method is selected from any one of wire rod coating, extrusion coating and micro-concave coating.

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