Pressure-sensitive adhesive composition, pressure-sensitive adhesive, preparation method of pressure-sensitive adhesive and polaroid

Abstract

The invention provides a pressure-sensitive adhesive composition, a pressure-sensitive adhesive, a preparation method of the pressure-sensitive adhesive and a polaroid. The pressure-sensitive adhesive composition is prepared from the following components in parts by weight: 50 to 60 parts of a main monomer, 40 to 50 parts of a hard monomer, 2 to 4 parts of a functional monomer, 20 to 30 parts of a high refractive index monomer, 0.5 to 0.7 part of an initiator and 80 to 100 parts of a solvent, wherein the high-refractive-index monomer is a first high-refractive-index monomer, and the first high-refractive-index monomer at least comprises an acrylic ester monomer containing a sulfur element. The pressure-sensitive adhesive composition provided by the invention not only can improve the refractive index of the pressure-sensitive adhesive, but also can fill tiny pores and uneven surfaces of the polaroid and display panel glass while meeting the basic performance requirements of the polaroid, so that light rays smoothly pass through the polaroid and a display panel, scattering and reflection of the light rays are reduced, and the quality of the display panel is improved. Therefore, the optical transmission efficiency of the polaroid and the display panel is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of optical adhesives, and in particular to a pressure-sensitive adhesive composition, a pressure-sensitive adhesive and a preparation method thereof, and a polarizer. Background Art

[0002] Display panels have become an indispensable product in daily life since their introduction in the 20th century, and polarizers, as key components, have also received extensive attention and research. Polarizers are composed of an outer protective film, an inner protective film, a PVA film, a phase difference film, a pressure-sensitive adhesive, and a release film. When the polarizer acts on the panel, light whose vibration direction is perpendicular to the transmission axis of the polarizer will be absorbed, and parallel light will be transmitted, thereby converting natural light into polarized light, thereby achieving the purpose of normal imaging.

[0003] In the display field, there will be inevitable light loss caused by reflection, which will reduce the light output efficiency of the panel. Therefore, the development of a polarizer with high refractive function can adjust the light path, improve contrast and brightness, which is of great significance to the display industry. Summary of the invention

[0004] The main purpose of the present invention is to provide a pressure-sensitive adhesive composition, a pressure-sensitive adhesive and a preparation method thereof, and a polarizer to solve the problems in the prior art that the low refractive index of the pressure-sensitive adhesive leads to high light loss and poor light extraction efficiency of the polarizer.

[0005] In order to achieve the above-mentioned object, according to one aspect of the present invention, a pressure-sensitive adhesive composition is provided, which comprises, by weight: 50 to 60 parts of a main monomer, 40 to 50 parts of a hard monomer, 2 to 4 parts of a functional monomer, 20 to 30 parts of a high-refractive monomer, 0.5 to 0.7 parts of an initiator and 80 to 100 parts of a solvent; wherein the high-refractive monomer is a first high-refractive monomer, and the first high-refractive monomer comprises at least one sulfur-containing acrylic ester monomer.

[0006] Furthermore, the sulfur-containing acrylic ester monomer is phenylthioethyl acrylate and / or 3-phenylthiobenzyl acrylate; preferably, the high-refractive monomer also includes a second high-refractive monomer, and the second high-refractive monomer is selected from any one or more of 4-biphenylmethanol acrylate, 3-phenoxybenzyl acrylate, isobornyl methacrylate and phenoxyethyl acrylate; preferably, the mass ratio of the first high-refractive monomer to the second high-refractive monomer is 1:0.5~2.

[0007] Furthermore, the pressure-sensitive adhesive composition also includes a filler, the filler is zirconium oxide and / or titanium oxide, and / or the mass of the filler is 0.1 to 90% of the total mass of the pressure-sensitive adhesive composition, preferably 10 to 60%, and more preferably 30 to 50%; and / or the particle size of zirconium oxide is 50 to 500 nm, and / or the particle size of titanium oxide is 50 to 100 nm; preferably, when the filler is zirconium oxide and titanium oxide, the mass ratio of zirconium oxide to titanium oxide is 1:0.1 to 5.

[0008] Furthermore, the main monomer is selected from any one or more of isobutyl acrylate, methyl acrylate, butyl acrylate, butyl methacrylate, alkoxy acrylate and isooctyl acrylate.

[0009] Furthermore, the hard monomer is selected from any one or more of methyl acrylate, methyl methacrylate, acrylamide, vinyl acetate, acrylonitrile, ethyl methacrylate, n-butyl methacrylate and styrene.

[0010] Further, the functional monomer is selected from any one or more of hydroxypropyl acrylate, acrylamide, acrylic acid, glycidyl acrylate, N-hydroxymethylacrylic acid amide, itaconic acid and hydroxyethyl acrylate, and / or the initiator is selected from any one or more of benzoyl peroxide, isopropyl peroxide, azobisisobutyronitrile and azobisvaleronitrile; and / or the solvent is selected from any one or more of butanone, ethyl acrylate, butyl acetate, ethyl acetate and toluene.

[0011] According to another aspect of the present invention, a method for preparing a pressure-sensitive adhesive is provided, the method comprising: step S1, dividing the above-mentioned pressure-sensitive adhesive composition into two parts to obtain a first composition and a second composition; step S2, performing a first mixing and a second mixing on the first composition and the second composition, respectively, to obtain a first mixture and a second mixture; step S3, performing a first reaction on the first mixture to obtain a first reactant; and step S4, adding the second mixture to the first reactant to perform a second reaction and cooling to obtain a pressure-sensitive adhesive.

[0012] Furthermore, in the above step S1, the amounts of the main monomer, the hard monomer, the functional monomer and the high-refractive monomer in the first composition and the second composition are respectively the same; the ratio of the mass of the initiator in the second composition to its mass in the first composition is 0.5 to 2:1; the ratio of the mass of the solvent in the second composition to its mass in the first composition is 0.5 to 2:1; and / or in the above step S3, the temperature of the first reaction is 75 to 85°C, and the time of the first reaction is 2 to 3 hours; and / or in the above step S4, the temperature of the second reaction is 75 to 85°C, and the time of the second reaction is 4.5 to 5.5 hours.

[0013] According to another aspect of the present invention, a pressure-sensitive adhesive is provided. The pressure-sensitive adhesive is prepared by the above-mentioned preparation method.

[0014] According to another aspect of the present invention, a polarizer is provided, comprising a polarizing film layer, a pressure-sensitive adhesive layer and a release film layer, wherein the pressure-sensitive adhesive layer is the above-mentioned pressure-sensitive adhesive.

[0015] By applying the technical scheme of the present invention, the pressure-sensitive adhesive composition of the present application can not only improve the refractive index of the pressure-sensitive adhesive by controlling the weight fractions of the main monomer, hard monomer, functional monomer, high refractive monomer, initiator and solvent within the above range, but also can meet the basic performance requirements of the polarizer while filling the tiny pores and uneven surfaces of the polarizer and display panel glass, so that the light can pass through the polarizer and display panel smoothly, reduce the scattering and reflection of the light, and thus improve the optical transmission efficiency of the polarizer and display panel. Among them, the main monomer can not only serve as the basic skeleton of the pressure-sensitive adhesive, but also can adjust the viscosity, transparency and flexibility of the pressure-sensitive adhesive; the hard monomer can not only enhance the cohesion inside the pressure-sensitive adhesive, but also improve the heat resistance, creep resistance, shear holding capacity and viscosity strength of the pressure-sensitive adhesive; the functional monomer can produce a cross-linking reaction during the polymerization process, thereby improving the cohesive strength, heat resistance, solvent resistance and shear strength of the pressure-sensitive adhesive; the high refractive monomer has a higher refractive index, which can make the pressure-sensitive adhesive maintain light transmittance while maintaining viscosity and transparency. The initiator can promote the polymerization reaction of the above monomers, thereby controlling the polymerization rate of the monomers and the molecular weight of the pressure-sensitive adhesive; the solvent can dissolve the above monomers and the initiator, thereby forming a solution that is easy to apply. It is further preferred that the first high-refractive monomer includes at least one sulfur-containing acrylic ester monomer, and the introduction of sulfur can form more cross-linking points or intermolecular forces, thereby enhancing the cohesion, heat resistance, adhesive strength and flexibility of the pressure-sensitive adhesive. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0017] Figure 1 A schematic diagram of the polarizer of the present application is shown.

[0018] Among them, the above drawings include the following reference numerals:

[0019] 1. Polarizer layer; 2. Pressure-sensitive adhesive layer; 3. Release film layer. DETAILED DESCRIPTION

[0020] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0021] As analyzed in the background technology of this application, there are problems in the prior art such as low refractive index of pressure-sensitive adhesive leading to high light loss of polarizer and poor light extraction efficiency. In order to solve the above problems, this application provides a pressure-sensitive adhesive composition, a pressure-sensitive adhesive and a preparation method thereof, and a polarizer.

[0022] In a typical embodiment of the present application, a pressure-sensitive adhesive composition is provided, which comprises, by weight, 50 to 60 parts of a main monomer, 40 to 50 parts of a hard monomer, 2 to 4 parts of a functional monomer, 20 to 30 parts of a high-fold monomer, 0.5 to 0.7 parts of an initiator, and 80 to 100 parts of a solvent; wherein the high-fold monomer is a first high-fold monomer, and the first high-fold monomer comprises at least one sulfur-containing acrylic ester monomer.

[0023] The pressure-sensitive adhesive composition of the present application can not only improve the refractive index of the pressure-sensitive adhesive by controlling the weight fractions of the main monomer, hard monomer, functional monomer, high-refractive monomer, initiator and solvent within the above range, but also can meet the basic performance requirements of the polarizer while filling the tiny pores and uneven surfaces of the polarizer and display panel glass, so that the light can pass through the polarizer and display panel smoothly, reduce the scattering and reflection of the light, and thus improve the optical transmission efficiency of the polarizer and display panel. Among them, the main monomer can not only serve as the basic skeleton of the pressure-sensitive adhesive, but also can adjust the viscosity, transparency and flexibility of the pressure-sensitive adhesive; the hard monomer can not only enhance the cohesion inside the pressure-sensitive adhesive, but also improve the heat resistance, creep resistance, shear holding capacity and viscosity strength of the pressure-sensitive adhesive; the functional monomer can produce a cross-linking reaction during the polymerization process, thereby improving the cohesive strength, heat resistance, solvent resistance and shear strength of the pressure-sensitive adhesive; the high-refractive monomer has a higher refractive index, which can make the pressure-sensitive adhesive maintain light transmittance while maintaining viscosity and transparency. The initiator can promote the polymerization reaction of the above monomers, thereby controlling the polymerization rate of the monomers and the molecular weight of the pressure-sensitive adhesive; the solvent can dissolve the above monomers and the initiator, thereby forming a solution that is easy to apply. It is further preferred that the high-fold monomer is the first high-fold monomer, and the first high-fold monomer includes at least one sulfur-containing acrylic ester monomer. The introduction of sulfur can form more cross-linking points or intermolecular forces, thereby enhancing the cohesion, heat resistance, adhesive strength and flexibility of the pressure-sensitive adhesive.

[0024] In one embodiment of the present application, the sulfur-containing acrylic ester monomer is phenylthioethyl acrylate and / or 3-phenylthiobenzyl acrylate; preferably, the high-refractive monomer also includes a second high-refractive monomer, and the second high-refractive monomer is selected from any one or more of 4-biphenylmethanol acrylate, 3-phenoxybenzyl acrylate, isobornyl methacrylate and phenoxyethyl acrylate; preferably, the mass ratio of the first high-refractive monomer to the second high-refractive monomer is 1:0.5~2.

[0025] The type of acrylic ester monomer containing sulfur element is preferably selected, and the high refractive index monomer also includes a second high refractive index monomer. The type of the second high refractive index monomer is preferably controlled within the above range, and the mass ratio of the first high refractive index monomer to the second high refractive index monomer is further controlled within the above range, which helps the first high refractive index monomer and the second high refractive index monomer to produce a synergistic effect, thereby enhancing the cohesion, adhesive strength and flexibility of the pressure-sensitive adhesive, and further improving the refractive index of the pressure-sensitive adhesive.

[0026] In one embodiment of the present application, the pressure-sensitive adhesive composition also includes a filler, the filler is zirconium oxide and / or titanium oxide, and / or the mass of the filler is 0.1 to 90% of the total mass of the pressure-sensitive adhesive composition, preferably 10 to 60%, and more preferably 30 to 50%; and / or the particle size of zirconium oxide is 50 to 500 nm, and / or the particle size of titanium oxide is 50 to 100 nm; and / or when the filler is zirconium oxide and titanium oxide, the mass ratio of zirconium oxide to titanium oxide is 1:0.1 to 5.

[0027] Preferably, the pressure-sensitive adhesive composition further includes a filler, and the type, mass and particle size of the filler are controlled within the above range, which helps to improve the wear resistance, tensile strength, thermal stability and optical properties of the pressure-sensitive adhesive. Further preferably, the filler is zirconium oxide and titanium oxide, wherein zirconium oxide helps to improve the thermal stability of the pressure-sensitive adhesive, and titanium oxide helps to improve the hiding power and whiteness of the pressure-sensitive adhesive, and preferably the mass ratio of zirconium oxide to titanium oxide is controlled within the above range, which helps to further enhance the wear resistance and tensile strength of the pressure-sensitive adhesive.

[0028] In one embodiment of the present application, the main monomer is selected from any one or more of isobutyl acrylate, methyl acrylate, butyl acrylate, butyl methacrylate, alkoxy acrylate and isooctyl acrylate.

[0029] The type of the main monomer is preferably within the above range, which helps to improve the adhesive strength, transparency and flexibility of the pressure-sensitive adhesive, and is beneficial to improving its synergistic coordination with other components in the pressure-sensitive adhesive composition.

[0030] In one embodiment of the present application, the hard monomer is selected from any one or more of methyl acrylate, methyl methacrylate, acrylamide, vinyl acetate, acrylonitrile, ethyl methacrylate, n-butyl methacrylate and styrene.

[0031] The type of hard monomer is preferably within the above range, which not only helps to enhance the internal cohesion of the pressure-sensitive adhesive, but also helps to improve the heat resistance, creep resistance, shear holding capacity and adhesive strength of the pressure-sensitive adhesive, and is beneficial to improving its synergistic coordination with other components in the pressure-sensitive adhesive composition.

[0032] In one embodiment of the present application, the functional monomer is selected from any one or more of hydroxypropyl acrylate, acrylamide, acrylic acid, glycidyl acrylate, N-hydroxymethylacrylic acid amide, itaconic acid and hydroxyethyl acrylate, and / or the initiator is selected from any one or more of benzoyl peroxide, isopropyl peroxide, azobisisobutyronitrile and azobisvaleronitrile; and / or the solvent is any one or more of butanone, ethyl acrylate (EA), butyl acetate, ethyl acetate and toluene.

[0033] Preferably, the types of functional monomers, initiators and solvents are within the above ranges. The functional monomers help to produce cross-linking reactions during the polymerization process, thereby improving the cohesive strength, heat resistance, solvent resistance and shear strength of the pressure-sensitive adhesive; the initiator helps to promote the polymerization reaction of the above monomers, thereby controlling the polymerization rate of the monomers and the molecular weight of the pressure-sensitive adhesive; the solvent helps to dissolve the above monomers and initiators, thereby forming a solution that is easy to coat.

[0034] In another typical embodiment of the present application, a method for preparing a pressure-sensitive adhesive is provided, the preparation method comprising: step S1, dividing the above-mentioned pressure-sensitive adhesive composition into two parts to obtain a first composition and a second composition; step S2, performing a first mixing and a second mixing on the first composition and the second composition, respectively, to obtain a first mixture and a second mixture; step S3, performing a first reaction on the first mixture to obtain a first reactant; and step S4, adding the second mixture to the first reactant to perform a second reaction and cooling to obtain a pressure-sensitive adhesive.

[0035] The present application uses the pressure-sensitive adhesive composition as a raw material to be divided into two parts, and conducts step-by-step reactions, namely the first reaction and the second reaction, so as to control the reaction amount of the above-mentioned monomers, thereby controlling the intensity of the first reaction and the second reaction, thereby reducing the phenomenon of violent polymerization during the reaction; at the same time, by controlling the amount of initiator and solvent added, not only the intensity of the first reaction and the second reaction can be controlled, but also the excessive viscosity of the pressure-sensitive adhesive can be alleviated. In addition, adding the initiator in batches in the first reaction and the second reaction can improve the stability of the initiator concentration throughout the polymerization reaction, thereby facilitating the polymerization reaction, thereby improving the conversion rate of the above-mentioned monomers.

[0036] In one embodiment of the present application, in the above step S1, the amounts of the main monomer, hard monomer, functional monomer and high-refractive monomer in the first composition and the second composition are respectively the same; the ratio of the mass of the initiator in the second composition to its mass in the first composition is 0.5 to 2:1; the ratio of the mass of the solvent in the second composition to its mass in the first composition is 0.5 to 2:1; and / or in the above step S3, the temperature of the first reaction is 75 to 85°C, and the time of the first reaction is 2 to 3 hours; and / or in the above step S4, the temperature of the second reaction is 75 to 85°C, and the time of the second reaction is 4.5 to 5.5 hours.

[0037] Controlling the mass ratio of the main monomer, hard monomer, functional monomer and high refractive index monomer in the first composition and the second composition within the above range helps to control the intensity of the first reaction and the second reaction, thereby reducing the phenomenon of violent polymerization during the reaction. At the same time, controlling the mass ratio of the initiator and the solvent in the first composition and the second composition within the above range can not only help to control the intensity of the first reaction and the second reaction, but also help to control the viscosity of the pressure-sensitive adhesive. Controlling the temperature and time of the first reaction and the second reaction within the above reaction helps the above monomers, initiators and solvents to undergo polymerization and cross-linking reactions, thereby forming a high refractive index pressure-sensitive adhesive.

[0038] In another typical embodiment of the present application, a pressure-sensitive adhesive is provided. The pressure-sensitive adhesive is prepared by the above-mentioned preparation method.

[0039] The pressure-sensitive adhesive prepared by the pressure-sensitive adhesive composition of the present application through the above-mentioned preparation method not only has a high refractive index, but also can meet the basic performance requirements of the polarizer while filling the tiny pores and uneven surfaces of the polarizer and the display panel glass, thereby allowing light to pass smoothly, reducing light scattering and reflection, and thereby improving optical transmission efficiency.

[0040] In another typical embodiment of the present application, a polarizer is provided, comprising a polarizing film layer, a pressure-sensitive adhesive layer and a release film layer, wherein the pressure-sensitive adhesive layer is the above-mentioned pressure-sensitive adhesive.

[0041] The polarizer containing the pressure-sensitive adhesive of the present application has a high refractive function, which helps to adjust the light path, improve contrast and brightness, and is better applied to various types of display panels such as VA, IPS and OLED.

[0042] The beneficial effects of the present application will be further illustrated below in conjunction with embodiments.

[0043] Example 1

[0044] A first composition including 25 parts of main monomer isobutyl acrylate, 20 parts of hard monomer methyl methacrylate, 1.2 parts of functional monomer acrylic acid, 25 parts of high-fold monomer phenylthioethyl acrylate, 0.2 parts of initiator isobutyl peroxide, and 33 parts of solvent ethyl acrylate is mixed for the first time to obtain a first mixture; a second composition including 25 parts of isobutyl acrylate, 20 parts of methyl methacrylate, 1.2 parts of acrylic acid, 0.4 parts of isobutyl peroxide, and 66 parts of ethyl acrylate is mixed for the second time to obtain a second mixture; the first mixture is put into a reactor, the temperature is raised to 80°C and a first reaction is carried out for 2 hours to obtain a first reactant; the second mixture is put into the first reactant, the second reaction is continued at 80°C for 5 hours, the reaction liquid is cooled and then discharged to obtain a pressure-sensitive adhesive.

[0045] Example 2

[0046] A first composition including 25 parts of main monomer isobutyl acrylate, 20 parts of hard monomer methyl methacrylate, 1.2 parts of functional monomer acrylic acid, 20 parts of high-refractive monomers 3-phenylthiobenzyl acrylate and 5 parts of 4-biphenylmethanol acrylate, 0.2 parts of initiator isopropyl peroxide, and 33 parts of solvent ethyl acrylate are mixed for the first time to obtain a first mixture; a second composition including 25 parts of isobutyl acrylate, 20 parts of methyl methacrylate, 1.2 parts of acrylic acid, 0.4 parts of isopropyl peroxide, and 66 parts of ethyl acrylate are mixed for the second time to obtain a second mixture; the first mixture is put into a reactor, the temperature is raised to 80°C and a first reaction is carried out for 2 hours to obtain a first reactant; the second mixture is put into the first reactant, the second reaction is continued at 80°C for 5 hours, the reaction liquid is cooled and then discharged to obtain a pressure-sensitive adhesive.

[0047] Example 3

[0048] A first composition including 25 parts of main monomer isobutyl acrylate, 20 parts of hard monomer methyl methacrylate, 1.2 parts of functional monomer acrylic acid, 20 parts of high-refractive monomers 3-phenylthiobenzyl acrylate and 5 parts of phenoxyethyl acrylate, 0.2 parts of initiator isobutyl peroxide, and 33 parts of solvent ethyl acrylate are mixed for the first time to obtain a first mixture; a second composition including 25 parts of isobutyl acrylate, 20 parts of methyl methacrylate, 1.2 parts of acrylic acid, 0.4 parts of isobutyl peroxide, and 66 parts of ethyl acrylate are mixed for the second time to obtain a second mixture; the first mixture is put into a reactor, the temperature is raised to 80°C and a first reaction is carried out for 2 hours to obtain a first reactant; the second mixture is put into the first reactant, the second reaction is continued at 80°C for 5 hours, the reaction liquid is cooled and then discharged to obtain a pressure-sensitive adhesive.

[0049] Example 4

[0050] The difference from Example 2 is that the first high-folding monomer in the high-folding monomer is 3-phenylthiobenzyl acrylate, the second high-folding monomer is 4-biphenylmethanol acrylate, the mass ratio of 3-phenylthiobenzyl acrylate to 4-biphenylmethanol acrylate is 15:10, and a pressure-sensitive adhesive is finally obtained.

[0051] Example 5

[0052] The difference from Example 2 is that the first high-folding monomer in the high-folding monomer is 3-phenylthiobenzyl acrylate, the second high-folding monomer is 4-biphenylmethanol acrylate, the mass ratio of 3-phenylthiobenzyl acrylate to 4-biphenylmethanol acrylate is 1:2, and a pressure-sensitive adhesive is finally obtained.

[0053] Example 6

[0054] The difference from Example 2 is that the first high-folding monomer in the high-folding monomer is 3-phenylthiobenzyl acrylate, the second high-folding monomer is 4-biphenylmethanol acrylate, the mass ratio of 3-phenylthiobenzyl acrylate to 4-biphenylmethanol acrylate is 1:10, and a pressure-sensitive adhesive is finally obtained.

[0055] Example 7

[0056] The difference from Example 1 is that the high-fold monomer is 4-biphenylmethanol acrylate, and the pressure-sensitive adhesive is finally obtained.

[0057] Example 8

[0058] The difference from Example 1 is that the high-fold monomer is isobornyl methacrylate, and a pressure-sensitive adhesive is finally obtained.

[0059] Example 9

[0060] The difference from Example 1 is that a certain amount of pressure-sensitive adhesive composition is taken, and a mixed medium of titanium oxide and zirconium oxide with a mass fraction of 10% and a particle size of 50 nm is added and mixed evenly, wherein the mass ratio of titanium oxide to zirconium oxide is 1:1, and finally a pressure-sensitive adhesive is obtained.

[0061] Example 10

[0062] The difference from Example 1 is that a certain amount of pressure-sensitive adhesive composition is taken, and a mixed medium of titanium oxide with a mass fraction of 40% and a particle size of 100 nm and zirconium oxide with a particle size of 500 nm is added and mixed evenly, wherein the mass ratio of titanium oxide to zirconium oxide is 1:1, and finally a pressure-sensitive adhesive is obtained.

[0063] Embodiment 11

[0064] The difference from Example 9 is that the particle size of zirconium oxide is 550 nm, the particle size of titanium oxide is 120 nm, and the pressure-sensitive adhesive is finally obtained.

[0065] Example 12

[0066] The difference from Example 9 is that the mass ratio of titanium oxide to zirconium oxide is 5:1, and a pressure-sensitive adhesive is finally obtained.

[0067] Example 13

[0068] The difference from Example 9 is that the mass ratio of titanium oxide to zirconium oxide is 6:1, and a pressure-sensitive adhesive is finally obtained.

[0069] Embodiment 14

[0070] The difference from Example 9 is that a certain amount of the pressure-sensitive adhesive composition is taken, and 0.05% by mass of titanium oxide is added to finally obtain the pressure-sensitive adhesive.

[0071] Embodiment 15

[0072] A first composition including 30 parts of main monomer isobutyl acrylate, 25 parts of hard monomer methyl methacrylate, 2 parts of functional monomer acrylic acid, 25 parts of high-fold monomer phenylthioethyl acrylate, 0.3 parts of initiator isobutyl peroxide, and 25 parts of solvent ethyl acrylate is mixed for the first time to obtain a first mixture; a second composition including 30 parts of isobutyl acrylate, 25 parts of methyl methacrylate, 2 parts of acrylic acid, 0.4 parts of isobutyl peroxide, and 55 parts of ethyl acrylate is mixed for the second time to obtain a second mixture; the first mixture is put into a reactor, the temperature is raised to 80°C and a first reaction is carried out for 2 hours to obtain a first reactant; the second mixture is put into the first reactant, the second reaction is continued at 80°C for 5 hours, the reaction liquid is cooled and then discharged to obtain a pressure-sensitive adhesive.

[0073] Example 16

[0074] A first composition including 25 parts of main monomer isobutyl acrylate, 20 parts of hard monomer methyl methacrylate, 1.2 parts of functional monomer acrylic acid, 25 parts of high-fold monomer phenylthioethyl acrylate, 0.2 parts of initiator isobutyl peroxide, and 33 parts of solvent ethyl acrylate is mixed for the first time to obtain a first mixture; a second composition including 25 parts of isobutyl acrylate, 20 parts of methyl methacrylate, 1.2 parts of acrylic acid, 0.4 parts of isobutyl peroxide, and 66 parts of ethyl acrylate is mixed for the second time to obtain a second mixture; the first mixture is put into a reactor, the temperature is raised to 75°C and a first reaction is carried out for 3 hours to obtain a first reactant; the second mixture is put into the first reactant, the second reaction is continued at 75°C for 5.5 hours, the reaction liquid is cooled and then discharged to obtain a pressure-sensitive adhesive.

[0075] Comparative Example 1

[0076] A first composition including 25 parts of main monomer isobutyl acrylate, 20 parts of hard monomer methyl methacrylate, 1.2 parts of functional monomer acrylic acid, 0.2 parts of initiator isobutyl peroxide, and 33 parts of solvent ethyl acrylate is mixed for the first time to obtain a first mixture; a second composition including 25 parts of isobutyl acrylate, 20 parts of methyl methacrylate, 1.2 parts of acrylic acid, 0.4 parts of isobutyl peroxide, and 66 parts of ethyl acrylate is mixed for the second time to obtain a second mixture; the first mixture is put into a reactor, the temperature is raised to 80°C and a first reaction is carried out for 2 hours to obtain a first reactant; the second mixture is put into the first reactant, the second reaction is continued at 80°C for 5 hours, the reaction liquid is cooled and then discharged to obtain a pressure-sensitive adhesive.

[0077] Test method:

[0078] Take a certain amount of pressure-sensitive adhesive, add 0.35wt% cross-linking agent and mix evenly, apply it on the TAC side of the polarizing film, dry it at 100-120℃ for 3-5min, cool it to room temperature, take samples and test the performance.

[0079] The refractive index of the polarizer is tested using an Abbe refractometer, and the test results are shown in Table 1.

[0080] Table 1

[0081] Implementation / Comparative Example Refractive index / % Example 1 1.573 Example 2 1.596 Example 3 1.592 Example 4 1.625 Example 5 1.612 Example 6 1.585 Example 7 1.574 Example 8 1.573 Example 9 1.624 Example 10 1.677 Embodiment 11 1.612 Example 12 1.623 Example 13 1.618 Embodiment 14 1.588 Embodiment 15 1.569 Example 16 1.572 Comparative Example 1 1.468

[0082] in, Figure 1 is a schematic diagram of the polarizer of the present application, from Figure 1 It can be seen that the polarizer includes a polarizer layer 1, a pressure-sensitive adhesive layer 2, and a release film layer 3, and the polarizer layer 1 is composed of a protective film, a polarizing film layer and a protective film.

[0083] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects:

[0084] The pressure-sensitive adhesive composition of the present application can not only improve the refractive index of the pressure-sensitive adhesive by controlling the weight fractions of the main monomer, hard monomer, functional monomer, high-refractive monomer, initiator and solvent within the above range, but also can meet the basic performance requirements of the polarizer while filling the tiny pores and uneven surfaces of the polarizer and display panel glass, so that the light can pass through the polarizer and display panel smoothly, reduce the scattering and reflection of the light, and thus improve the optical transmission efficiency of the polarizer and display panel. Among them, the main monomer can not only serve as the basic skeleton of the pressure-sensitive adhesive, but also can adjust the viscosity, transparency and flexibility of the pressure-sensitive adhesive; the hard monomer can not only enhance the cohesion inside the pressure-sensitive adhesive, but also improve the heat resistance, creep resistance, shear holding capacity and viscosity strength of the pressure-sensitive adhesive; the functional monomer can produce a cross-linking reaction during the polymerization process, thereby improving the cohesive strength, heat resistance, solvent resistance and shear strength of the pressure-sensitive adhesive; the high-refractive monomer has a higher refractive index, which can make the pressure-sensitive adhesive maintain light transmittance while maintaining viscosity and transparency. The initiator can promote the polymerization reaction of the above monomers, thereby controlling the polymerization rate of the monomers and the molecular weight of the pressure-sensitive adhesive; the solvent can dissolve the above monomers and the initiator, thereby forming a solution that is easy to apply. It is further preferred that the high-fold monomer is the first high-fold monomer, and the first high-fold monomer includes at least one sulfur-containing acrylic ester monomer. The introduction of sulfur can form more cross-linking points or intermolecular forces, thereby enhancing the cohesion, heat resistance, adhesive strength and flexibility of the pressure-sensitive adhesive.

[0085] The above are only embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A pressure-sensitive adhesive composition, characterized in that: In parts by weight, the pressure-sensitive adhesive composition comprises: 50-60 parts of the main monomer; 40-50 parts of hard monomer; 2 to 4 parts of functional monomers; 20-30 parts of high-fold monomer; 0.5 to 0.7 parts of an initiator; and 80-100 parts of solvent; Wherein, the high-refractive-number monomer is a first high-refractive-number monomer, and the first high-refractive-number monomer includes at least one acrylic ester monomer containing sulfur element.

2. The pressure-sensitive adhesive composition according to claim 1, characterized in that: The sulfur-containing acrylic ester monomer is phenylthioethyl acrylate and / or 3-phenylthiobenzyl acrylate; preferably, the high-refractive monomer also includes a second high-refractive monomer, and the second high-refractive monomer is selected from any one or more of 4-biphenylmethanol acrylate, 3-phenoxybenzyl acrylate, isobornyl methacrylate and phenoxyethyl acrylate; preferably, the mass ratio of the first high-refractive monomer to the second high-refractive monomer is 1:0.5-2.

3. The pressure-sensitive adhesive composition according to claim 1 or 2, characterized in that: The pressure-sensitive adhesive composition also includes a filler, and the filler is zirconium oxide and / or titanium oxide, and / or the mass of the filler is 0.1 to 90% of the total mass of the pressure-sensitive adhesive composition, preferably 10 to 60%, and more preferably 30 to 50%; and / or the particle size of the zirconium oxide is 50 to 500 nm, and / or the particle size of the titanium oxide is 50 to 100 nm; preferably, when the filler is zirconium oxide and titanium oxide, the mass ratio of zirconium oxide to titanium oxide is 1:0.1 to 5.

4. The pressure-sensitive adhesive composition according to any one of claims 1 to 3, characterized in that: The main monomer is selected from any one or more of isobutyl acrylate, methyl acrylate, butyl acrylate, butyl methacrylate, alkoxy acrylate and isooctyl acrylate.

5. The pressure-sensitive adhesive composition according to any one of claims 1 to 4, characterized in that: The hard monomer is selected from any one or more of methyl acrylate, methyl methacrylate, acrylamide, vinyl acetate, acrylonitrile, ethyl methacrylate, n-butyl methacrylate and styrene.

6. The pressure-sensitive adhesive composition according to any one of claims 1 to 5, characterized in that: The functional monomer is selected from any one or more of hydroxypropyl acrylate, acrylamide, acrylic acid, glycidyl acrylate, N-hydroxymethylacrylic acid amide, itaconic acid and hydroxyethyl acrylate, and / or the initiator is selected from any one or more of benzoyl peroxide, cumene peroxide, azobisisobutyronitrile and azobisvaleronitrile; and / or the solvent is selected from any one or more of butanone, ethyl acrylate, butyl acetate, ethyl acetate and toluene.

7. A method for preparing a pressure-sensitive adhesive, characterized in that: The preparation method comprises: Step S1, dividing the pressure-sensitive adhesive composition of claim 1 into two parts to obtain a first composition and a second composition; Step S2, performing a first mixing and a second mixing on the first composition and the second composition, respectively, to obtain a first mixture and a second mixture; Step S3, subjecting the first mixture to a first reaction to obtain a first reactant; and Step S4, adding the second mixture to the first reactant to perform a second reaction and cooling to obtain a pressure-sensitive adhesive.

8. The preparation method according to claim 7, characterized in that: In the step S1, the main monomer, the hard monomer, the functional monomer and the high-refractive monomer are used in the same amounts in the first composition and the second composition; The ratio of the mass of the initiator in the second composition to the mass of the initiator in the first composition is 0.5 to 2:1; The ratio of the mass of the solvent in the second composition to the mass of the solvent in the first composition is 0.5 to 2:1; And / or in the step S3, the temperature of the first reaction is 75-85° C., and the time of the first reaction is 2-3 hours; And / or in the step S4, the temperature of the second reaction is 75-85° C., and the time of the second reaction is 4.5-5.5 hours.

9. A pressure-sensitive adhesive, characterized in that: The pressure-sensitive adhesive is prepared by the preparation method described in claim 7 or 8.

10. A polarizer, comprising a polarizing film layer, a pressure-sensitive adhesive layer and a release film layer, characterized in that: The pressure-sensitive adhesive layer is the pressure-sensitive adhesive according to claim 9.

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