阅读说明：本技术 用于制备偏光膜的组合物、偏光膜的制备方法及偏光膜、显示模组 (Composition for preparing polarizing film, preparation method of polarizing film, polarizing film and display module ) 是由 陈梅 于 2021-07-30 设计创作，主要内容包括：本申请公开了一种用于制备偏光膜的组合物、偏光膜的制备方法及偏光膜、显示模组,所述组合物包括可聚合二向性染料、液晶性可聚合单体以及交联剂。在本申请提供的用于制备偏光膜的组合物中,通过在可聚合二向性染料中加入液晶性可聚合单体和交联剂,使得制备得到的偏光膜的柔韧性增大,从而能够提高偏光膜的弯折性能。(The application discloses a composition for preparing a polarizing film, a preparation method of the polarizing film, the polarizing film and a display module. In the composition for preparing the polarizing film provided by the application, the prepared polarizing film has increased flexibility by adding the liquid crystal polymerizable monomer and the cross-linking agent into the polymerizable dichroic dye, so that the bending performance of the polarizing film can be improved.)

1. A composition for preparing a polarizing film, comprising a polymerizable bidirectional dye, a liquid crystalline polymerizable monomer and a crosslinking agent.

2. The composition according to claim 1, wherein the liquid-crystalline polymerizable monomer is selected from Andone kind of (1).

3. The composition of claim 1, wherein the composition further comprises a photoinitiator and a solvent.

4. The composition according to claim 3, wherein in a mixed system of the polymerizable dichroic dye, the liquid crystal polymerizable monomer, the crosslinking agent, the photoinitiator and the solvent, the mass content of the polymerizable dichroic dye is 10 wt% to 20 wt%, the mass content of the liquid crystal polymerizable dye is 10 wt% to 20 wt%, the mass content of the crosslinking agent is 45 wt% to 58 wt%, the mass content of the photoinitiator is 0.5 wt% to 2 wt%, and the mass content of the solvent is 5 wt% to 15 wt%.

5. The composition of claim 3, further comprising an accelerator, wherein the molar amount of the accelerator and the molar amount of the crosslinking agent in the composition are in a relationship of 1mol of the accelerator to 5mol to 40mol of the crosslinking agent.

6. A method for producing a polarizing film, characterized by comprising the steps of:

providing a composition comprising a polymerizable bidirectional dye, a liquid crystalline polymerizable monomer, and a crosslinking agent;

the polymerizable dichroic dye, the liquid crystal polymerizable monomer and the cross-linking agent react at a preset temperature to form a polarizing film;

stretching the polarizing film;

and irradiating the polarizer film with ultraviolet light to form a polarizing film.

7. The method for preparing a polarizing film according to claim 6, wherein the step of reacting the polymerizable dichroic dye, the liquid crystal polymerizable monomer, and the crosslinking agent at a preset temperature to form a polarizing film comprises:

mixing the polymerizable bidirectional dye, the liquid crystal polymerizable monomer and the cross-linking agent to form a first mixed solution;

the polymerizable dichroic dye, the liquid crystal polymerizable monomer and the cross-linking agent react at a preset temperature to form a second mixed solution;

and curing the second mixed solution to form the polarizing film.

8. The method for producing a polarizing film according to claim 7, wherein the composition further comprises an accelerator, a photoinitiator, and a solvent, and the step of mixing a polymerizable dichroic dye, the liquid-crystalline polymerizable monomer, and the crosslinking agent comprises:

mixing the polymerizable bidirectional dye, the liquid crystal polymerizable monomer, the cross-linking agent, the photoinitiator and the solvent to form a mixed system;

adding the accelerator to the mixed system to form a first mixed solution.

9. A polarizing film produced by the method for producing a polarizing film according to any one of claims 6 to 8.

10. A display module, comprising a display panel and a polarizing film disposed on at least one side of the display panel, wherein the polarizing film is the polarizing film according to claim 9.

Technical Field

The application relates to the technical field of display, in particular to a composition for preparing a polarizing film, a preparation method of the polarizing film, the polarizing film and a display module.

Background

The flexible display technology is a development trend in the current display field, and the future display technology is developed towards any form display directions such as flexible folding, flexible curling and flexible stretching. Wherein the flexible material is a core carrier for flexible display technology. At present, a polarizer is a key structure for restricting the flexible display technology.

The dye polarizer is a polarizer depending on the anisotropic absorption characteristic of the dichroic dye, but the existing dye polarizer has high hardness, so that the bending performance of the polarizer is poor, and the development of the flexible display technology is not facilitated.

Disclosure of Invention

The embodiment of the application provides a composition for preparing a polarizing film, a preparation method of the polarizing film, the polarizing film and a display module, and aims to solve the technical problem that in the prior art, the bending performance of a polarizer is poor.

The embodiment of the application provides a composition for preparing a polarizing film, which comprises a polymerizable bidirectional dye, a liquid crystal polymerizable monomer and a crosslinking agent.

Optionally, in the composition provided by the application, the liquid crystal polymerizable monomer is selected from One kind of (1).

Optionally, in the compositions provided herein, the composition further comprises a photoinitiator and a solvent.

Optionally, in the composition provided by the present application, in a mixed system composed of the polymerizable dichroic dye, the liquid crystal polymerizable monomer, the crosslinking agent, the photoinitiator, and the solvent, the mass content of the polymerizable dichroic dye is 10 wt% to 20 wt%, the mass content of the liquid crystal polymerizable dye is 10 wt% to 20 wt%, the mass content of the crosslinking agent is 45 wt% to 58 wt%, the mass content of the photoinitiator is 0.5 wt% to 2 wt%, and the mass content of the solvent is 5 wt% to 15 wt%.

Optionally, in the composition provided herein, the composition further comprises an accelerator, and in the composition, the molar amount of the accelerator and the molar amount of the crosslinking agent are in a corresponding relationship of 1mol of the accelerator to 5mol to 40mol of the crosslinking agent.

The embodiment of the application also provides a preparation method of the polarizing film, which comprises the following steps:

providing a composition comprising a polymerizable bidirectional dye, a liquid crystalline polymerizable monomer, and a crosslinking agent;

the polymerizable dichroic dye, the liquid crystal polymerizable monomer and the cross-linking agent react at a preset temperature to form a polarizing film;

stretching the polarizing film;

and irradiating the polarizer film with ultraviolet light to form a polarizing film.

Optionally, in the composition provided herein, the step of reacting the polymerizable dichroic dye, the liquid crystal polymerizable monomer, and the crosslinking agent at a preset temperature to form a polarizing film includes:

mixing the polymerizable bidirectional dye, the liquid crystal polymerizable monomer and the cross-linking agent to form a first mixed solution;

the polymerizable dichroic dye, the liquid crystal polymerizable monomer and the cross-linking agent react at a preset temperature to form a second mixed solution;

and curing the second mixed solution to form the polarizing film.

Optionally, in the composition provided herein, the composition further includes an accelerator, a photoinitiator, and a solvent, and the step of mixing the polymerizable dichroic dye, the liquid crystal polymerizable monomer, and the crosslinking agent includes:

mixing the polymerizable bidirectional dye, the liquid crystal polymerizable monomer, the cross-linking agent, the photoinitiator and the solvent to form a mixed system;

adding the accelerator to the mixed system to form a first mixed solution.

Embodiments of the present application provide a polarizing film prepared by the method for preparing a polarizing film according to any one of the preceding embodiments.

The embodiment of the application also provides a display module, which comprises a display panel and a polarizer arranged on at least one side of the display panel, wherein the polarizer comprises the polarizing film in the embodiment.

The application provides a composition for preparing a polarizing film, a preparation method of the polarizing film, the polarizing film and a display module.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

Fig. 1 is a schematic flow chart of a method for producing a polarizing film provided herein.

Fig. 2 is a reaction mechanism diagram in the process of preparing the polarizing film provided by the present application.

Fig. 3 is a schematic structural diagram of a polarizing film provided herein.

Fig. 4 is a schematic structural diagram of a display module provided in the present application.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application. Furthermore, it should be understood that the detailed description and specific examples, while indicating exemplary embodiments of the invention, are given by way of illustration and explanation only, and are not intended to limit the scope of the invention. In the present application, unless indicated to the contrary, the use of the directional terms "upper" and "lower" generally refer to the upper and lower positions of the device in actual use or operation, and more particularly to the orientation of the figures of the drawings; while "inner" and "outer" are with respect to the outline of the device.

The embodiment of the application provides a composition for preparing a polarizing film, a preparation method of the polarizing film, the polarizing film and a display module. The following are detailed below. It should be noted that the following description of the embodiments is not intended to limit the preferred order of the embodiments.

The embodiments of the present application provide a composition for preparing a polarizing film. The composition comprises a polymerizable bidirectional dye, a liquid crystalline polymerizable monomer and a crosslinking agent.

In the composition provided by the application, the prepared polarizing film has increased flexibility by adding the liquid crystal polymerizable monomer and the cross-linking agent into the polymerizable dichroic dye, so that the bending performance of the polarizing film can be improved, and the bending performance of the polarizer using the polarizing film can be further improved. In addition, since the liquid crystalline polymerizable monomer also has good stretching properties, the above arrangement can also improve the stretching properties of the polarizing film produced using the above composition.

Wherein the polymerizable bidirectional dye may be at least one selected from anthraquinone-based dyes and azo-based dyes capable of undergoing a crosslinking reaction.

In some embodiments, the polymerizable bidirectional dye has a carbon-carbon double bond at the end. For example, the polymerizable dichroic dye may be

The liquid crystal polymerizable monomer may be at least one selected from an acrylate compound and a vinyl ether compound.

In some embodiments, the liquid crystalline polymerizable monomer may be selected from At least one of (1).

The crosslinker may be a thiol crosslinker. The thiol crosslinking agent may be selected from at least one of bifunctional, trifunctional, and tetrafunctional thiol compounds.

In some embodiments, the thiol crosslinker comprises a first thiol crosslinker and a second thiol crosslinker. The first thiol crosslinker and the second thiol crosslinker can both be selected from At least one of (1). The first thiol crosslinker and the second thiol crosslinker are different.

In the present application, the kind of the additive is not particularly limited. For example, in some embodiments, the additives may include a promoter, a photoinitiator, and a solvent.

The accelerator may be a tertiary amine compound, such as a polycyclic tertiary amine or a benzyl cyclic tertiary amine. The accelerator may also be other compounds capable of accelerating the crosslinking reaction, such as at least one compound selected from the group consisting of 2, 4, 6 tris (dimethylaminomethyl) phenol, 1, 3, 3-tetraphenyl-1, 3-disiloxane diol, 1, 4-bis (hydroxydimethylsilyl) benzene, and phthalimide.

The photoinitiator may be at least one selected from the group consisting of 2, 2-dimethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenyl-1-propanone, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-2- (4-morpholinyl) -1- [4- (methylthio) phenyl ] -1-propanone, 2, 4, 6-trimethylbenzoyl-diphenylphosphine oxide, ethyl 2, 4, 6-trimethylbenzoylphenylphosphonate, and 2-dimethylamino-2-benzyl-1- [4- (4-morpholinyl) phenyl ] -1-butanone.

The solvent may be at least one selected from the group consisting of toluene, acetone, dichloromethane, chloroform, dichloroethane, tetrahydrofuran, cyclohexane, and methyl formate.

In the present application, there is no particular requirement for the mass percentages of the components in the composition. In some embodiments, the composition comprises a polymerizable dichroic dye, a liquid crystalline polymerizable monomer, a crosslinking agent, an accelerator, a photoinitiator, and a solvent. The polymerizable bidirectional dye, the liquid crystal polymerizable monomer, the cross-linking agent, the photoinitiator and the solvent form a mixed system. In the mixed system, the mass content of the polymerizable bidirectional dye is 10 wt% -20 wt%, the mass content of the liquid crystal polymerizable monomer is 10 wt% -20 wt%, the mass content of the cross-linking agent is 45 wt% -58 wt%, the mass content of the photoinitiator is 0.5 wt% -2 wt%, and the mass content of the solvent is 5 wt% -15 wt%. It will be understood by those skilled in the art that the sum of the mass percentages of all components in the mixed system should be 100 wt%.

In the composition, the molar amount of the accelerator and the molar amount of the crosslinking agent are in a corresponding relationship of 1mol of the accelerator to 5mol to 40mol of the crosslinking agent. When the crosslinker is a thiol crosslinker, the crosslinker will have a thiol functional group. Wherein, in said composition, the molar amount of said accelerator and the molar amount of said mercapto-functional group correspond in a relationship such that 1mol of said accelerator corresponds to 50mol to 150mol of said mercapto-functional group.

Referring to fig. 1, an embodiment of the present application further provides a method for preparing a polarizing film, where the method for preparing a polarizing film includes the following steps:

providing a composition comprising a polymerizable bidirectional dye, a liquid crystalline polymerizable monomer, and a crosslinking agent;

the polymerizable dichroic dye, the liquid crystal polymerizable monomer and the cross-linking agent react at a preset temperature to form a polarizing film;

stretching the polarizing film;

and irradiating the polarizer film with ultraviolet light to form a polarizing film.

In the preparation method of the polarizing film, the polymerizable dichroic dye, the liquid crystal polymerizable monomer and the cross-linking agent in the composition are used for reaction, and the reaction product is the liquid crystal elastomer, so that the flexibility of the polarizing film prepared by using the liquid crystal elastomer as the functional film material is increased, and the bending performance of the polarizing film can be improved. In addition, since the liquid crystal polymerizable monomer also has good stretching performance, the above arrangement can also improve the stretching performance of the polarizing film, thereby improving the stretching performance of the polarizing film.

The method for producing the polarizing film provided in this example is explained in detail below.

B1: provided is a composition including a polymerizable bidirectional dye, a liquid crystalline polymerizable monomer, and a crosslinking agent.

Wherein the polymerizable bidirectional dye may be at least one selected from anthraquinone-based dyes and azo-based dyes capable of undergoing a crosslinking reaction.

In some embodiments, the polymerizable bidirectional dye has a carbon-carbon double bond at the end. For example, the polymerizable dichroic dye may be

The liquid crystal polymerizable monomer may be at least one selected from an acrylate compound and a vinyl ether compound.

In some embodiments, the liquid crystalline polymerizable monomer may be selected from At least one of (1).

The crosslinker may be a thiol crosslinker. The thiol crosslinking agent may be selected from at least one of bifunctional, trifunctional, and tetrafunctional thiol compounds.

In some embodiments, the thiol crosslinker comprises a first thiol crosslinker and a second thiol crosslinker. The first thiol crosslinker and the second thiol crosslinker can both be selected from At least one of (1). The first thiol crosslinker and the second thiol crosslinker are different.

In this embodiment, the composition further comprises an accelerator, a photoinitiator, and a solvent.

Wherein the accelerator is used to increase the rate of the crosslinking reaction. The accelerator may be a tertiary amine compound, such as a polycyclic tertiary amine or a benzyl cyclic tertiary amine. The accelerator may also be other compounds capable of accelerating the crosslinking reaction, such as at least one compound selected from the group consisting of 2, 4, 6 tris (dimethylaminomethyl) phenol, 1, 3, 3-tetraphenyl-1, 3-disiloxane diol, 1, 4-bis (hydroxydimethylsilyl) benzene, and phthalimide.

The photoinitiator may be at least one selected from the group consisting of 2, 2-dimethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenyl-1-propanone, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-2- (4-morpholinyl) -1- [4- (methylthio) phenyl ] -1-propanone, 2, 4, 6-trimethylbenzoyl-diphenylphosphine oxide, ethyl 2, 4, 6-trimethylbenzoylphenylphosphonate, and 2-dimethylamino-2-benzyl-1- [4- (4-morpholinyl) phenyl ] -1-butanone.

The solvent may be at least one selected from the group consisting of toluene, acetone, dichloromethane, chloroform, dichloroethane, tetrahydrofuran, cyclohexane, and methyl formate.

B2: the polymerizable dichroic dye, the liquid crystal polymerizable monomer and the cross-linking agent react at a preset temperature to form the polarizing film.

In this embodiment, step B2 specifically includes the following steps:

b21: mixing the polymerizable bidirectional dye, the liquid crystal polymerizable monomer and the cross-linking agent to form a first mixed solution.

Step B21 specifically includes:

b211: the polymerizable dichroic dye, the liquid crystal polymerizable monomer, the cross-linking agent, the photoinitiator and the solvent are mixed to form a mixed system.

In the mixed system, the mass content of the polymerizable bidirectional dye is 10 wt% to 20 wt%, such as 10 wt%, 12 wt%, 15 wt%, 18 wt% or 20 wt%. The mass content of the liquid crystal polymerizable dye is 10 wt% to 20 wt%, and may be 10 wt%, 12 wt%, 15 wt%, 18 wt%, or 20 wt%. The mass content of the cross-linking agent is 45 wt% to 58 wt%, and may be 45 wt%, 48 wt%, 50 wt%, 52 wt%, 55 wt% or 58 wt%, for example. The photoinitiator may be present in an amount of 0.5 wt% to 2 wt%, such as 0.5 wt%, 1 wt%, 1.2 wt%, 1.5 wt%, or 2 wt%. The mass content of the solvent is 5 wt% to 15 wt%, and may be 5 wt%, 8 wt%, 10 wt%, 12 wt%, or 15 wt%.

B212: adding the accelerator to the mixed system to form a first mixed solution.

First, the accelerator is dissolved in a solvent. Wherein, the solvent for dissolving the promoter can be at least one selected from toluene, acetone, dichloromethane, chloroform, dichloroethane, tetrahydrofuran, cyclohexane and methyl formate. The mass ratio of the promoter to the solvent is 1: 10 (10-100), such as 1: 10, 1: 25, 1: 50, 1: 70, 1: 80 or 1: 100.

Next, a solution in which an accelerator is dissolved is added to the above-mentioned mixed system, thereby obtaining a first mixed solution. Wherein the molar amount of the accelerator and the molar amount of the crosslinking agent are in a corresponding relationship of 1mol of the accelerator to 5mol to 40mol of the crosslinking agent. Specifically, the correspondence between the molar amount of the accelerator and the molar amount of the crosslinking agent may be 1mol of the accelerator to 5mol of the crosslinking agent. The correspondence between the molar amount of the accelerator and the molar amount of the crosslinking agent may be such that 1mol of the accelerator corresponds to 20mol of the crosslinking agent. The correspondence between the molar amount of the accelerator and the molar amount of the crosslinking agent may be such that 1mol of the accelerator corresponds to 40mol of the crosslinking agent.

In this embodiment, the crosslinker is a thiol crosslinker. The thiol crosslinker has a thiol functional group. The molar amount of said accelerator and the molar amount of said mercapto-functional group are related such that 1mol of said accelerator corresponds to 50mol to 150mol of said mercapto-functional group. Specifically, the correspondence between the molar amount of the accelerator and the molar amount of the mercapto functional group may be 1mol of the accelerator to 50mol of the mercapto functional group. The correspondence between the molar amount of the accelerator and the molar amount of the mercapto functional group may be such that 1mol of the accelerator corresponds to 100mol of the mercapto functional group. The correspondence between the molar amount of said accelerator and the molar amount of said mercapto-functional group may also be such that 1mol of said accelerator corresponds to 150mol of said mercapto-functional group.

B22: and defoaming the first mixed solution under the vacuum condition.

B23: and placing the first mixed solution after the defoaming treatment in a mold.

The material of the mold may include polyethylene, or may be other materials that do not react with the components in the first mixed solution. The specific material of the mold is not limited in this application.

B24: in the mold, the polymerizable bidirectional dye, the liquid crystal polymerizable monomer and the cross-linking agent react at a preset temperature to form a second mixed solution.

Wherein the preset temperature may be 20 ℃ to 30 ℃. In some embodiments, the preset temperature may specifically be 20 ℃, 22 ℃, 25 ℃, 28 ℃ or 30 ℃.

And at the preset temperature, the polymerizable bidirectional dye, the liquid crystal polymerizable monomer and the crosslinking agent are subjected to a crosslinking reaction to form a first intermediate product. The first intermediate product has a multi-domain liquid crystal micro-area structure. The crosslinking reaction may include crosslinking of the polymerizable dichroic dye itself, crosslinking of the liquid crystal polymerizable monomer itself, and crosslinking between the polymerizable dichroic dye and the liquid crystal polymerizable monomer by the crosslinking agent.

In this embodiment, both end portions of the polymerizable dichroic dye and the liquid-crystalline polymerizable monomer have a carbon-carbon double bond. The crosslinking agent is a thiol crosslinking agent. The thiol crosslinker has a thiol functional group. The crosslinking in the crosslinking reaction is substantially bonding of a carbon-carbon double bond and a mercapto functional group.

It should be noted that the components of the second mixed solution may include a solvent in addition to the crosslinked first intermediate product.

In addition, in the step of forming a first intermediate product through a crosslinking reaction of the polymerizable dichroic dye, the liquid crystal polymerizable monomer and the crosslinking agent, the reaction time can be 6h-24 h. In some embodiments, the reaction time may be 6h, 8h, 10h, 12h, 18, or 24 h.

B25: and curing the second mixed solution to form the polarizing film.

First, the solvent in the second mixed solution is removed to solidify the second mixed solution. For example, the second mixture may be cured by baking. Specifically, the mould with the second mixed solution is placed in a vacuum hot oven for 12-36 hours at the hot drying temperature of 80-100 ℃ to remove the solvent in the second mixed solution. In some embodiments, the heat baking temperature may be 80 ℃, 85 ℃, 90 ℃, 95 ℃, or 100 ℃. The standing time may be 12h, 18h, 20h, 24h, 30h or 36 h.

And secondly, demolding the cured second mixed solution to form the polarizing film.

B3: and stretching the polarizing film.

Specifically, the polarizing film is stretched in a uniaxial stretching manner, so that the polymerizable dichroic dye and the liquid crystal polymerizable monomer are uniaxially oriented together along a stretching direction. Wherein the elongation after stretching is 115-140%.

B4: and irradiating the polarizer film with ultraviolet light to form a polarizing film.

When the polarizer film is in a stretching state, under the irradiation of ultraviolet light, the polymerizable dichroic dye in the polarizer film and the carbon-carbon double bond in the liquid crystal polymerizable monomer are subjected to polymerization reaction to form a polymer network, so that the polarizing film is obtained. Wherein the polymer network anchors the orientation state of the polymerizable dichroic dye molecules to achieve the anisotropic absorption function of the polarizing film.

Wherein, in the ultraviolet irradiation process, the ultraviolet intensity is 5mV/cm²-30mV/cm². The ultraviolet irradiation time is 5min-30 min. In some embodiments, the ultraviolet light intensity may be 5mV/cm²、10mV/cm²、15mV/cm²、20mV/cm²、25mV/cm²Or 30mV/cm². The ultraviolet light irradiation time can be 5min, 10min, 15min, 20min, 25min or 30 min.

Referring to fig. 2, in the method for preparing a polarizing film provided in this embodiment, a reaction mechanism of the polymerizable dichroic dye a and the liquid crystal polymerizable monomer B is as follows:

(1) thermal polymerization: under the action of a first thiol crosslinking agent C and a second thiol crosslinking agent D, a polymerizable bidirectional dye A and a liquid crystal polymerizable monomer B are crosslinked at a preset temperature to form a first intermediate product, and a polarizing film is formed at the same time;

(2) stretching treatment: stretching the polarizing film, wherein the elongation sigma is 115-140%;

(3) ultraviolet polymerization: under the irradiation of ultraviolet light, carbon-carbon double bonds in the polymerizable bidirectional dye A and the liquid crystal polymerizable monomer B are crosslinked to form a polymer grid, and meanwhile, the polarizing film is obtained.

The following describes a method for producing a polarizer according to the present application with reference to specific examples. In the following examples, the polymerizable dichroic dye isThe liquid crystalline polymerizable monomer isThe thiol crosslinking agent comprises a first thiol crosslinking agent and a second thiol crosslinking agent, wherein the first thiol crosslinking agent isThe second thiol crosslinker isThe promoter is benzyl ring tertiary amine, the photoinitiator is 2, 2-dimethoxy-2-phenylacetophenone, and the solvent is toluene.

(1) The method comprises the steps of mixing polymerizable dichroic dye, liquid crystal polymerizable monomer, first thiol crosslinking agent, photoinitiator and solvent to form a mixed system.

In the mixed system, the mass content of the polymerizable bidirectional dye is 15 wt%, the mass content of the liquid crystalline polymerization monomer is 20 wt%, the mass content of the first thiol crosslinking agent is 26 wt%, the mass content of the second thiol crosslinking agent is 27 wt%, the mass content of the photoinitiator is 2 wt%, and the mass content of the solvent is 10 wt%. The first thiol crosslinker and the second thiol crosslinker both have thiol functional groups.

(2) The promoter is separately dissolved in toluene and then added into the mixed system to form a first mixed solution.

Firstly, the accelerator is separately dissolved in toluene according to the mass ratio of 1: 50, and then the mixed solution of the accelerator and the toluene is added into the mixed system to obtain a first mixed solution. Wherein the molar amount of the accelerator and the molar amount of the mercapto-functional group are related such that 1mol of the accelerator corresponds to 100mol of the mercapto-functional group.

(3) And carrying out vacuum defoaming treatment on the first mixed solution.

(4) And quickly adding the defoamed first mixed solution into a mold made of polyethylene, and reacting at room temperature for 12 hours. In the mold, the polymerizable bidirectional dye, the liquid crystal polymerizable monomer, the first thiol crosslinking agent and the second thiol crosslinking agent react at 20 ℃ to form a second mixed solution.

(5) And placing the mold in a vacuum hot oven for 24 hours to remove the toluene in the second mixed solution, wherein the hot oven temperature is 100 ℃. After the heat baking, the second mixed solution is solidified.

(6) And demolding the cured second mixed solution to form the polarizing film.

(7) Carrying out uniaxial tension treatment on the polarizing film, wherein the elongation is 140%;

(8) under the condition that the polaroid film is kept in a stretching state, ultraviolet light irradiation is carried out on the polaroid film; wherein the ultraviolet light intensity is 20mV/cm²The ultraviolet irradiation time is 20 min.

According to the preparation method of the polarizing film, the polymerizable bidirectional dye, the liquid crystal polymerizable monomer and the cross-linking agent in the composition are used for reaction, and the reaction product is the liquid crystal elastomer, so that the flexibility of the polarizing film prepared by taking the liquid crystal elastomer as the functional film material is increased, and the polarizing film has a polarizing function and excellent mechanical properties. In addition, the dichroic dye is a polymerizable molecule, and after the polarizer film is prepared, when the polarizer film is stretched, the polymerizable dichroic dye and the liquid crystal polymerizable monomer in the polarizer film are subjected to a cross-linking polymerization reaction in a stretched state, so that the orientation state of the polymerizable dichroic dye is fixed, and therefore, an additional process is not required to maintain the orientation state of the polarizer film, and the process can be simplified.

Referring to fig. 3, an embodiment of the present application further provides a polarizing film 10, and the polarizing film 10 can be prepared by the method for preparing a polarizing film described in the foregoing embodiment, which is not described herein again.

In the polarizing film 10 of the present embodiment, since the orientation state of the polarizing film 10 has been fixed in the manufacturing process, it is not necessary to adopt an additional process to maintain the orientation state of the polarizing film 10. Therefore, when the polarizer using the polarizing film 10 is manufactured, the use of a protective film such as a TAC film may be omitted, so that the polarizer has both a polarizing function and excellent mechanical properties, and the film structure is simpler, thereby not only improving the bending performance of the polarizer, but also realizing the thinning design of the polarizer.

Referring to fig. 4, an embodiment of the present application further provides a display module 100. The display module 100 includes a display panel 20 and a polarizing film 10 disposed on at least one side of the display panel 20, and the polarizing film 10 may be the polarizing film 10 of the foregoing embodiment.

The display module 100 may be an organic light emitting diode display module. The polarizing film 10 is disposed on the display side of the display panel 20. The display panel 20 includes a flexible substrate 201 and a flexible display layer 202, which are sequentially disposed. The display module 100 further includes a quarter-wave plate 30 and a flexible cover plate 40. The quarter-wave plate 30 is disposed between the flexible display layer 202 and the polarizing film 10. The flexible cover 40 is disposed on a side of the polarizing film 10 away from the quarter-wave plate 30.

In this embodiment, the manufacturing method of the display module 100 includes: firstly, the flexible display layer 202 is prepared on the flexible substrate 201, and then the quarter-wave plate 30, the polarizing film 10 and the flexible cover plate 40 are sequentially attached to the flexible display layer 202 through the optical pressure sensitive adhesive, so that the display module 100 is obtained.

Because the product obtained by the reaction of the polymerizable dichroic dye, the liquid crystal polymerizable monomer and the cross-linking agent has good flexibility similar to a rubber elastomer and good mechanical property, the application improves the flexibility of the polarizing film 10 by using the polarizing film 10 added with the liquid crystal polymerizable monomer, thereby improving the bending property of the display module 100. In addition, since the orientation state of the polymerizable dichroic dye is fixed during the manufacturing process, the use of a protective film such as a TAC film can be omitted, thereby achieving a slim design of the display module 100.

In some embodiments, the display module 100 may also be a liquid crystal display module. Both sides of the display panel 20 are provided with linear polarizers including the polarizing film 10, which will not be described in detail herein.

The composition for preparing a polarizing film, the method for preparing a polarizing film, the polarizing film and the display module provided in the examples of the present application are described in detail, and the principles and embodiments of the present application are explained in the present application by using specific examples, and the description of the examples is only provided to help understanding the method and the core concept of the present application; meanwhile, for those skilled in the art, according to the idea of the present application, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present application.