CN116203753A - A kind of gray polymer dispersed liquid crystal thin film and preparation method thereof - Google Patents

Abstract

The invention discloses a grey polymer dispersed liquid crystal film and a preparation method thereof. The preparation method comprises the following steps: (1) Preparing blue-violet dye liquid crystal A, orange dye liquid crystal B and blue dye liquid crystal C; (2) Uniformly mixing blue-violet dye liquid crystal A, orange dye liquid crystal B and blue dye liquid crystal C to form gray dye liquid crystal; (3) Uniformly mixing the gray dye liquid crystal with the polymer monomer composition to form isotropic liquid crystal mixed solution at room temperature; (4) Mixing the liquid crystal mixed solution with glass beads, then clamping the mixture into two transparent conductive films, and rolling to form a liquid crystal film; and then solidifying the liquid crystal film. The gray polymer dispersed liquid crystal film has a larger total light transmittance difference value in an electrified state and a powered-off state; when the transparent color is changed between the transparent state and the frosted state, the transparent color has obvious color shade change, and can meet the application scene with high requirements.

Description

A kind of gray polymer dispersed liquid crystal thin film and preparation method thereof

technical field

The invention relates to the technical field of liquid crystal film preparation, in particular to a gray polymer dispersed liquid crystal film and a preparation method thereof.

Background technique

Polymer-dispersed liquid crystal film is a film formed by micron-sized liquid crystal droplets embedded in a continuous polymer matrix. Under the control of the electric field, using the external field responsiveness of the liquid crystal molecules, and according to the matching degree of the refractive index of the liquid crystal droplet and the polymer matrix, the two states of the light scattering state and the transparent state can be switched mutually.

Chinese patent 201210560826.4 discloses a method for preparing a colored polymer-dispersed liquid crystal film. The liquid crystal film is prepared by mixing anthraquinone dyes or azo dyes into liquid crystal raw materials, and then mixing them with polymer monomers evenly to prepare A colored polymer dispersed liquid crystal film. Using the dye as the guest, the liquid crystal as the main body, and the guest-host effect, the dye molecules are turned over with the flipping of the liquid crystal molecules under the action of the electric field, and the color of the polymer dispersed liquid crystal film changes with the change between the transparent state and the frosted state. change. In this patent, the weight ratio of liquid crystal disperse black (azo dye) to liquid crystal raw material is 1:99, heated at 60°C and stirred for 10 hours, so that the liquid crystal and dye are evenly mixed; epoxy resin, curing agent glass beads and liquid crystal press The ratio is 1:1:0.5:1, mixed evenly, sandwiched between two transparent conductive films coated with ITO, and rolled evenly; heated at 80°C for 6 hours to cure, and a black PDLC film was obtained.

The invention patent is the superposition of strong absorption and scattering state (frosted state) in the non-energized state, and the superposition of weak absorption and transparent state (permeable state) in the electrified state. Through the on and off of the electric field, when the present invention changes between the transparent state and the frosted state, the color also changes accordingly (the depth of the color changes).

However, the inventors found in their research that the difference in total light transmittance between the power-on state and the power-off state of the colored polymer-dispersed liquid crystal film prepared by the above-mentioned patent method is not large enough, which in turn leads to its The degree of change in the depth of the color when changing between matte states is not significant enough; it is difficult to meet high-demand application scenarios. Therefore, it is of great application value to provide a dispersed liquid crystal film with a large difference in total light transmittance between the power-on state and the power-off state.

Contents of the invention

In order to overcome at least one of the technical problems existing in the prior art, the present invention firstly provides a method for preparing a gray polymer-dispersed liquid crystal film.

Technical scheme of the present invention is:

A kind of preparation method of gray polymer dispersed liquid crystal thin film, it comprises the steps:

(1) Prepare blue-violet dye liquid crystal A, orange dye liquid crystal B, and blue dye liquid crystal C;

(2) Mix blue-violet dye liquid crystal A, orange dye liquid crystal B and blue dye liquid crystal C uniformly to form gray dye liquid crystal;

(3) uniformly mixing the gray dye liquid crystal with the polymer monomer composition to form an isotropic liquid crystal mixture at room temperature;

(4) After mixing the liquid crystal mixture with glass beads, sandwich it in two transparent conductive films, roll to form a liquid crystal film; then solidify the liquid crystal film to obtain the gray polymer-dispersed liquid crystal film .

The inventor found in the research that the blue dye liquid crystal A, the orange dye liquid crystal B and the blue dye liquid crystal C were mixed evenly to form a gray dye liquid crystal; then the gray dye liquid crystal prepared by mixing the gray dye liquid crystal with the polymer monomer Material-dispersed liquid crystal film; it has a large difference in total light transmittance under the state of power-on and power-off; when it changes between the transparent state and the frosted state, it has a significant change in color depth, which can be Meet high-demand application scenarios.

What the inventor needs to explain here is that the step of forming gray dye liquid crystals by uniformly mixing blue-violet dye liquid crystal A, orange dye liquid crystal B and blue dye liquid crystal C is very critical; only mixing blue-violet dye liquid crystal A, orange dye liquid crystal B And the blue dye liquid crystal C is mixed evenly to form a gray dye liquid crystal; then the gray polymer dispersed liquid crystal film prepared by mixing the gray dye liquid crystal with the polymer monomer; it has a relatively high Large total light transmittance difference.

Preferably, the preparation method of blue-violet dye liquid crystal A in step (1) is: mixing blue-violet dye (liquid crystal manufacturer model 3YA-004-05) into liquid crystal 1, heating and stirring to uniformly color the liquid crystal material to form blue-violet dye liquid crystal A ;

Wherein, the blue-violet dye is a trisazo blue-violet dye;

The weight ratio of the blue-violet dye to the liquid crystal 1 is 1:99 to 6:94;

Preferably, the preparation method of orange dye liquid crystal B in step (1) is: mixing orange dye (liquid crystal manufacturer model 3YA-105-05) into liquid crystal 1, heating and stirring to uniformly color the liquid crystal raw material to form orange dye liquid crystal B;

Wherein, the orange dye is a naphthyl-substituted anthraquinone orange dye;

The weight ratio of the orange dye to the liquid crystal 1 is 1:99˜6:94.

Preferably, the preparation method of blue dye liquid crystal C in step (1) is: mixing blue dye (liquid crystal manufacturer model 3YA-005-05) into liquid crystal 1, heating and stirring to uniformly color the liquid crystal raw material to form blue dye liquid crystal B ;

Wherein, the blue dye is a phenyl substituent anthraquinone blue dye;

The weight ratio of the blue dye to the liquid crystal 1 is 1:99˜6:94.

Preferably, the liquid crystal 1 is a nematic mixed crystal (model 3YP-601 from a liquid crystal manufacturer).

Preferably, the weight ratio of purple liquid crystal A, orange liquid crystal B and blue liquid crystal C in step (2) is (0.35-0.48):(0.35-0.48):(0.15-0.20).

Preferably, liquid crystal 2 is also added in step (2); blue-violet dye liquid crystal A, orange dye liquid crystal B and blue dye liquid crystal C are mixed uniformly with liquid crystal 2 to form gray dye liquid crystal.

Further preferably, the weight ratio of purple liquid crystal A, orange liquid crystal B, blue liquid crystal C, and liquid crystal 2 described in step (2) is (0.28～0.38):(0.28～0.38):(0.12～0.15):( 0.18～0.22);

Preferably, the liquid crystal 2 is a nematic mixed crystal (model 3YP-502 from a liquid crystal manufacturer).

In the research, the inventor was further surprised to find that liquid crystal 2 was added in step (2); blue-violet dye liquid crystal A, orange dye liquid crystal B and blue dye liquid crystal C were mixed uniformly with liquid crystal 2 to form gray dye liquid crystal; A gray polymer dispersed liquid crystal film prepared by mixing gray dye liquid crystals with polymer monomers; the difference in total light transmittance between the power-on state and the power-off state has been further increased.

Preferably, the weight ratio of the gray dye liquid crystal to the polymer monomer composition in step (3) is 4:6˜6:4.

Preferably, the polymer monomer composition described in step (3) is a mixture of polymer monomers and initiators.

Further preferably, the polymer monomer is composed of methyl methacrylate and epoxy acrylic resin in a weight ratio of 7:3-8:2.

Further preferably, the weight ratio of the initiator to the polymer monomer is 0.3:99.7˜3:97.

Further preferably, the initiator is selected from one or a mixture of initiators 819, TPO and 184.

Preferably, the weight ratio of the glass microspheres to the liquid crystal mixture in step (4) is 0.1-5:99.9-95.

Further preferably, the particle size of the glass microspheres is: 5 μm-30 μm.

Preferably, the conductive layer of the transparent conductive film described in step (4) may be indium tin oxide, nano-silver, graphene, polyaniline or polythiophene.

Preferably, the curing described in step (4) specifically adopts ultraviolet light curing.

Further preferably, the UV curing time is 5 seconds to 5 minutes, and the UV light intensity is 2mw/cm ² -30mw/cm ² ).

The present invention also provides a gray polymer dispersed liquid crystal film prepared by the above preparation method.

Beneficial effects: the present invention provides a brand-new preparation method of gray polymer dispersed liquid crystal film; in this method, blue-violet dye liquid crystal A, orange dye liquid crystal B and blue dye liquid crystal C are uniformly mixed to form gray dye liquid crystal; and then The gray polymer dispersed liquid crystal film prepared by mixing the gray dye liquid crystal with the polymer monomer; it has a large difference in total light transmittance in the power-on state and the power-off state; making it in the transparent state When changing between the matte state and the matte state, it has a significant change in color depth, which can meet high-demand application scenarios. In particular, liquid crystal 2 is added in step (2); it can make the total light transmittance difference of the prepared gray polymer dispersed liquid crystal film in the power-on state and the power-off state be further increased; and then make The prepared gray polymer-dispersed liquid crystal film is more concealed in the frosted state, and clearer and more transparent in the transparent state.

Detailed ways

The present invention is further explained below in conjunction with specific examples, but the examples do not limit the present invention in any form.

The preparation of embodiment 1 gray polymer dispersed liquid crystal thin film

(1) Mix blue-violet dye (liquid crystal manufacturer model 3YA-004-05) into liquid crystal 1, heat and stir evenly to color the liquid crystal raw material to form blue-violet dye liquid crystal A; the blue-violet dye is trisazo blue-violet dye; The weight ratio of the blue-violet dye to the liquid crystal 1 is 5:95; the liquid crystal 1 is a nematic liquid crystal (model 601 from a liquid crystal manufacturer).

Mix orange dye (liquid crystal manufacturer model 3YA-105-05) into liquid crystal 1, heat and stir evenly to color the liquid crystal raw material to form orange dye liquid crystal B; the orange dye is a naphthyl-substituted anthraquinone orange dye; the orange dye The weight ratio to the liquid crystal 1 is 5:95; the liquid crystal 1 is a nematic mixed crystal (model 3YP-601 of the liquid crystal manufacturer).

Mix a blue dye (model number 3YA-005-05 of the liquid crystal manufacturer) into the liquid crystal 1, heat and stir evenly to color the liquid crystal raw material to form a blue dye liquid crystal C; the blue dye is a phenyl-substituted anthraquinone blue dye; The weight ratio of the blue dye to the liquid crystal 1 is 5:95; the liquid crystal 1 is a nematic mixed crystal (type 601 of the liquid crystal manufacturer).

(2) The blue-purple liquid crystal A, orange liquid crystal B, and blue liquid crystal C are uniformly mixed in a certain proportion to form a gray dye liquid crystal; the weight ratio of the purple liquid crystal A, orange liquid crystal B, and blue liquid crystal C is 0.38: 0.45:0.17.

(3) The gray liquid crystal is mixed uniformly with the polymer monomer composition to form an isotropic liquid crystal mixed liquid at room temperature, and the polymer monomer composition is a polymer monomer (methyl methacrylate and cyclic Oxygen acrylic resin), the mixture of initiator, the weight ratio of described gray liquid crystal and described polymer monomer composition is 48.5: 51.5; The weight ratio of described methyl methacrylate and epoxy acrylic resin is 7: 3 ; The initiator is the initiator TPO; The weight ratio of the initiator to the polymer monomer is 0.7:99.3.

(4) After mixing the liquid crystal mixture with glass beads, sandwich it in two transparent conductive films, and roll to form a liquid crystal film; the liquid crystal film is cured by ultraviolet light to make a gray polymer dispersed liquid crystal film;

The weight ratio of the glass microspheres to the liquid crystal mixture is 0.3:99.79; the conductive layer of the transparent conductive film can be indium tin oxide; the particle size of the glass microspheres is: 18 μm;

The UV curing time is 40 seconds, and the UV intensity is 10mw/cm ² .

The preparation of embodiment 2 gray polymer dispersed liquid crystal film

The difference between embodiment 2 and embodiment 1 is that liquid crystal 2 is also added in step (2); blue-violet dye liquid crystal A, orange dye liquid crystal B and blue dye liquid crystal C are mixed uniformly with liquid crystal 2 to form gray Dye liquid crystal. All the other are identical with embodiment 1.

Step (2) is specifically:

(2) Mix the blue-purple liquid crystal A, orange liquid crystal B, blue liquid crystal C, and liquid crystal 2 uniformly in a certain proportion to form a gray dye liquid crystal; the purple liquid crystal A, orange liquid crystal B, blue liquid crystal C, liquid crystal 2 The weight ratio is 0.3:0.36:0.14:0.2; the liquid crystal 2 is a nematic mixed crystal (model 3YP-502 of the liquid crystal manufacturer).

The preparation of embodiment 3 gray polymer dispersed liquid crystal film

(1) Mix blue-violet dye (liquid crystal manufacturer model 3YA-004-05) into liquid crystal 1, heat and stir evenly to color the liquid crystal raw material to form blue-violet dye liquid crystal A; the blue-violet dye is trisazo blue-violet dye; The weight ratio of the blue-violet dye to the liquid crystal 1 is 2:98; the liquid crystal 1 is a nematic liquid crystal (model 601 from a liquid crystal manufacturer).

Mix orange dye (liquid crystal manufacturer model 3YA-105-05) into liquid crystal 1, heat and stir evenly to color the liquid crystal raw material to form orange dye liquid crystal B; the orange dye is a naphthyl-substituted anthraquinone orange dye; the orange dye The weight ratio to the liquid crystal 1 is 3:97; the liquid crystal 1 is a nematic mixed crystal (model 3YP-601 of the liquid crystal manufacturer).

Mix a blue dye (model number 3YA-005-05 of the liquid crystal manufacturer) into the liquid crystal 1, heat and stir evenly to color the liquid crystal raw material to form a blue dye liquid crystal C; the blue dye is a phenyl-substituted anthraquinone blue dye; The weight ratio of the blue dye to the liquid crystal 1 is 3:97; the liquid crystal 1 is a nematic mixed crystal (type 601 of the liquid crystal manufacturer).

(2) Mix the blue-purple liquid crystal A, orange liquid crystal B, and blue liquid crystal C uniformly in a certain proportion to form a gray dye liquid crystal; the weight ratio of purple liquid crystal A, orange liquid crystal B, and blue liquid crystal C is 0.48: 0.38:0.14.

(3) The gray liquid crystal is mixed uniformly with the polymer monomer composition to form an isotropic liquid crystal mixed liquid at room temperature, and the polymer monomer composition is a polymer monomer (methyl methacrylate and cyclic Oxygen acrylic resin), the mixture of initiator, the weight ratio of described gray liquid crystal and described polymer monomer composition is 48.5: 51.5; The weight ratio of described methyl methacrylate and epoxy acrylic resin is 7: 3 ; The initiator is the initiator TPO; The weight ratio of the initiator to the polymer monomer is 0.3:99.7.

(4) After mixing the liquid crystal mixture with glass beads, sandwich it in two transparent conductive films, and roll to form a liquid crystal film; the liquid crystal film is cured by ultraviolet light to make a gray polymer dispersed liquid crystal film;

The weight ratio of the glass microspheres to the liquid crystal mixture is 0.3:99.7; the conductive layer of the transparent conductive film can be indium tin oxide; the particle size of the glass microspheres is: 18 μm;

The UV curing time is 30 seconds, and the UV light intensity is 15mw/cm ² .

The preparation of embodiment 4 gray polymer dispersed liquid crystal film

The difference between embodiment 4 and embodiment 3 is that liquid crystal 2 is also added in step (2); blue-violet dye liquid crystal A, orange dye liquid crystal B and blue dye liquid crystal C are mixed uniformly with liquid crystal 2 to form gray Dye liquid crystal. All the other are identical with embodiment 3.

Step (2) is specifically:

(2) Mix the blue-purple liquid crystal A, orange liquid crystal B, blue liquid crystal C, and liquid crystal 2 uniformly in a certain proportion to form a gray dye liquid crystal; describe the purple liquid crystal A, orange liquid crystal B, blue liquid crystal C, and liquid crystal 2 The weight ratio is 0.38:0.31:0.11:0.2; the liquid crystal 2 is a nematic mixed crystal (model 3YP-502 from the liquid crystal manufacturer).

The gray polymer dispersed liquid crystal film that embodiment 1～4 method is made is cut into 100mm*150mm sample, two electrodes are set at 100mm edge, measure (C light source, ASTM standard) with Hangzhou color spectrum haze meter CS700, use The output is driven by an AC60 volt (50HZ) power supply, and its total light transmittance is tested under power-on and power-off conditions; the test results are shown in Table 1.

Table 1.

As can be seen from the experiments in Table 1, the gray polymer-dispersed liquid crystal films prepared in Examples 1 and 3 have a large total light transmittance difference; The liquid crystal B and the blue dye liquid crystal C are mixed evenly to form a gray dye liquid crystal; then the gray polymer dispersed liquid crystal film is prepared by mixing the gray dye liquid crystal with the polymer monomer; it has The large total light transmittance difference makes it have a significant color depth change when it changes between the transparent state and the frosted state, which can meet high-demand application scenarios.

As can be seen from the table 1 experiment, the gray polymer dispersed liquid crystal film prepared in embodiment 2 is relative to embodiment 1, and the gray polymer dispersed liquid crystal film prepared in embodiment 4 is relative to embodiment 3; The transmittance difference has been further greatly increased; this shows that: add liquid crystal 2 in step (2); mix blue-violet dye liquid crystal A, orange dye liquid crystal B and blue dye liquid crystal C with liquid crystal 2 to form gray dye Liquid crystal; then the gray polymer dispersed liquid crystal film prepared by mixing the gray dye liquid crystal with the polymer monomer; the difference in total light transmittance between the power-on state and the power-off state has been further increased.

Claims (10)

1. a preparation method of gray polymer dispersed liquid crystal film, is characterized in that, comprises the steps: (1) Prepare blue-violet dye liquid crystal A, orange dye liquid crystal B, and blue dye liquid crystal C; (2) Mix blue-violet dye liquid crystal A, orange dye liquid crystal B and blue dye liquid crystal C uniformly to form gray dye liquid crystal; (3) uniformly mixing the gray dye liquid crystal with the polymer monomer composition to form an isotropic liquid crystal mixture at room temperature; (4) After mixing the liquid crystal mixture with glass beads, sandwich it in two transparent conductive films, roll to form a liquid crystal film; then solidify the liquid crystal film to obtain the gray polymer-dispersed liquid crystal film . 2. the preparation method of gray polymer dispersed liquid crystal thin film according to claim 1 is characterized in that, the preparation method of blue-violet dye liquid crystal A in the step (1) is: the blue-violet dye (liquid crystal factory model 3YA-004 -05) mixed into liquid crystal 1, heated and stirred evenly to color the liquid crystal raw material to form blue-violet dye liquid crystal A; Wherein, the blue-violet dye is a trisazo blue-violet dye; The weight ratio of the blue-violet dye to the liquid crystal 1 is 1:99 to 6:94; 3. the preparation method of gray polymer dispersed liquid crystal thin film according to claim 1 is characterized in that, the preparation method of orange dye liquid crystal B in the step (1) is: orange dye is mixed in the liquid crystal 1, heated and stirred to make Liquid crystal raw materials are colored to form orange dye liquid crystal B; Wherein, the orange dye is a naphthyl-substituted anthraquinone orange dye; The weight ratio of the orange dye to the liquid crystal 1 is 1:99˜6:94. 4. the preparation method of gray polymer dispersed liquid crystal thin film according to claim 1 is characterized in that, the preparation method of blue dye liquid crystal C in the step (1) is: blue dye is mixed in the liquid crystal 1, heating and stirring Evenly color the liquid crystal raw material to form blue dye liquid crystal C; Wherein, the blue dye is a phenyl substituent anthraquinone blue dye; The weight ratio of the blue dye to the liquid crystal 1 is 1:99˜6:94. 5 . The preparation method of gray polymer-dispersed liquid crystal film according to any one of claims 2 to 4 , characterized in that the liquid crystal 1 is a nematic mixed crystal. 6 . 6. the preparation method of gray polymer dispersed liquid crystal thin film according to claim 1 is characterized in that, the weight ratio of purple liquid crystal A described in step (2), orange liquid crystal B, blue liquid crystal C is (0.35 ~0.48): (0.35~0.48): (0.15~0.20). 7. the preparation method of gray polymer dispersed liquid crystal thin film according to claim 1 is characterized in that, also adds liquid crystal 2 in step (2); With blue-violet dye liquid crystal A, orange dye liquid crystal B and blue dye Liquid crystal C and liquid crystal 2 are evenly mixed to form gray dye liquid crystal. 8. the preparation method of gray polymer dispersed liquid crystal thin film according to claim 1 is characterized in that, the weight ratio of purple liquid crystal A, orange liquid crystal B, blue liquid crystal C, liquid crystal 2 described in step (2) Yes(0.28～0.38):(0.28～0.38):(0.12～0.15):(0.18～0.22); 9. The preparation method of the gray polymer-dispersed liquid crystal film according to claim 7, wherein the liquid crystal 2 is a nematic mixed crystal. 10. The gray polymer-dispersed liquid crystal film prepared by the preparation method described in any one of claims 1 to 9.