Phase difference film and preparation method thereof

Abstract

The invention provides a phase difference film and a preparation method, the phase difference film comprises a light alignment layer and a liquid crystal layer, the light alignment layer is formed by polymerizing a first composition, and the liquid crystal layer is formed by polymerizing a second composition; the first composition comprises first high-etherification-degree low-molecular-weight resin, first polyfunctional-group low-molecular-weight resin, a first silane coupling agent and a first acrylate polymer; the second composition comprises second high-etherification-degree low-molecular-weight resin, second polyfunctional-group low-molecular-weight resin and a second acrylate polymer; according to the formula and the preparation process of the photo-alignment layer and the liquid crystal layer in the phase difference film provided by the invention, the stripping of each layer of the liquid crystal phase difference film is controllable, and different laminating process requirements of panel manufacturers can be met.

Description

Technical Field

[0001] The present invention relates to the technical field of liquid crystal display, and in particular to a liquid crystal phase difference film with controllable interlayer peeling force and a preparation method thereof. Background Art

[0002] In recent years, with the advancement of display technology, liquid crystal displays (LCDs) and organic light-emitting diodes (OLEDs) have been widely used in various electronic devices, dominating the display market. However, in high-end applications with very strict viewing angles, flat-panel displays experience a significant decrease in image contrast when viewed from a direction that deviates from the normal to the display's orientation. Grayscale inversion can also occur at wide viewing angles.

[0003] To address these issues, breakthroughs and innovations in wide-viewing-angle technology have become a crucial area of ​​research for display engineers since the advent of active-matrix LCDs. Currently, popular wide-viewing-angle technologies include in-plane switching (IPS), fringe-field switching (FFS), and vertical-alignment active-matrix (VA). Vertical-alignment LCDs, with their advantages of higher contrast and shorter response times, have become a key area of ​​focus for wide-viewing-angle technology breakthroughs.

[0004] Since optical displays require liquid crystal retardation films to be used in combination with other optical films, in order to meet the different interlayer peeling requirements caused by different lamination methods of different manufacturers, it is necessary to provide a liquid crystal retardation film with controllable interlayer peeling. Summary of the Invention

[0005] In response to the existing technology, different manufacturers have different interlayer peeling requirements due to different lamination methods. The purpose of this application is to provide a liquid crystal retardation film and preparation process with controllable interlayer peeling. By adjusting the formulation of the liquid crystal layer and the photo-alignment layer in the liquid crystal retardation film, combined with the subsequent preparation process, controllable interlayer peeling of the liquid crystal retardation film can be achieved.

[0006] According to a first aspect of the present application, a phase difference film is provided, comprising a photo-alignment layer and a liquid crystal layer, wherein the photo-alignment layer is formed by polymerizing a first composition, and the liquid crystal layer is formed by polymerizing a second composition; the first composition comprises: a first high-etherification-degree low-molecular-weight resin, a first multifunctional low-molecular-weight resin, a first silane coupling agent, and a first acrylate polymer; the second composition comprises: a second high-etherification-degree low-molecular-weight resin, a second multifunctional low-molecular-weight resin, and a second acrylate polymer; wherein the first high-etherification-degree low-molecular-weight resin has an etherification degree of 5.23 or more and a molecular weight of less than 5000 g / mol, and the first multifunctional low-molecular-weight resin has two wherein the second high-etherification-degree low molecular weight resin has an etherification degree of 5.23 or more and a molecular weight of less than 5000 g / mol, the second multifunctional low molecular weight resin has two or more reactive functional groups and a molecular weight of less than 5000 g / mol, and the functional groups in the second multifunctional low molecular weight resin are selected from a combination of two or more of hydroxyl groups, acrylate groups, ethoxy groups, and methacrylate groups.

[0007] Preferably, the first composition further includes at least one of a photoinitiator, a catalyst, and a first solvent; and / or the second composition further includes a polymerizable liquid crystal composition, and the second composition further includes at least one of a second silane coupling agent, a leveling agent, and a second solvent.

[0008] Preferably, the first high-etherification degree low molecular weight resin accounts for 0.1%-5% of the total mass of the first composition, and / or the first multifunctional low molecular weight resin accounts for 1%-5% of the total mass of the first composition, and / or the first silane coupling agent accounts for 0.1%-5% of the total mass of the first composition, and / or the first acrylate polymer accounts for 0.15%-30% of the total mass of the first composition, and / or the photoinitiator accounts for 0.01%-10% of the total mass of the first composition, and / or the catalyst accounts for 0.1%-10% of the total mass of the first composition, and / or the first solvent accounts for 50%-95% of the total mass of the first composition.

[0009] Preferably, the second high-etherification degree low molecular weight resin accounts for 0.01%-10% of the total mass of the second composition by mass; and / or the second multifunctional low molecular weight resin accounts for 0.01%-2.00% of the total mass of the second composition by mass; and / or the polymerizable liquid crystal composition accounts for 1.5%-45% of the total mass of the second composition by mass; and / or the second acrylate polymer accounts for 0.1%-30% of the total mass of the second composition by mass; and / or the second silane coupling agent accounts for 0-5% of the total mass of the second composition by mass; and / or the leveling agent accounts for 0.01%-5% of the total mass of the second composition by mass; and / or the second solvent accounts for 50%-90% of the total mass of the second composition by mass.

[0010] Preferably, the first high-etherification low-molecular-weight resin is selected from the group consisting of one or more combinations of butylated melamine resin, melamine formaldehyde resin, methylated urea-formaldehyde resin, high-methylated melamine formaldehyde resin, n-butanol-etherified melamine resin, butanol-etherified urea-formaldehyde resin, isobutanol-etherified amino resin, catechol borate-etherified phenolic resin, dicyanophenyl-etherified phenol-biphenyl-phenolic resin, organic boron-modified bismaleimide resin, glycidyl-etherified bismaleimide resin, and hexamethoxymethyl melamine resin; the first multifunctional low-molecular-weight resin is selected from the group consisting of trimethylolpropane tripropylene glycol, ... A combination of one or more of esters, polyethylene glycol acrylate, dipropylene glycol diacrylate, trimethylolpropane trimethacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, ethoxylated glycerol triacrylate, dipentaerythritol penta / hexaacrylate, dimethylolpropionic acid diacrylate, ethoxylated trimethylolpropane triacrylate, and pentaerythritol triacrylate; the first silane coupling agent is selected from γ-aminopropyl triethoxysilane, N-(β-aminoethyl)-γ-aminopropyl trimethoxysilane, γ-glycidyl ether oxygen propyl trimethoxysilane, γ - a combination of one or more of glycidoxypropylmethyldiethoxysilane, vinyltriethoxysilane, γ-isocyanatepropyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-aminopropyltriethoxysilane, and trimethoxysilane; the number average molecular weight of the first acrylate polymer is in the range of 60,000 to 600,000 (GPC test), and the first acrylate polymer contains polar groups, and the polar groups include one or more of hydroxyl groups, carboxyl groups, hydroxymethyl groups, cyano groups, amino groups, amide groups, nitro groups, aldehyde groups, ketone groups, ester groups, and sulfonic acid groups.

[0011] Preferably, the second high etherification degree low molecular weight resin is selected from the group consisting of butylated melamine resin, melamine formaldehyde resin, methylated urea formaldehyde resin, high methylated melamine formaldehyde resin, n-butanol etherified melamine resin, butanol etherified urea formaldehyde resin, isobutanol etherified amino resin, catechol borate etherified phenolic resin, dicyanophenyl etherified phenol-biphenyl phenolic resin, organic boron modified bismaleimide resin, glycidyl etherified bismaleimide resin, hexamethoxymethyl melamine resin, or a combination thereof; the second multifunctional low molecular weight resin is selected from the group consisting of trimethylolpropane triacrylate, polyethylene glycol acrylate, dipropylene glycol diacrylate, , trimethylolpropane trimethacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, ethoxylated glycerol triacrylate, dipentaerythritol penta / hexaacrylate, dimethylolpropionic acid diacrylate, ethoxylated trimethylolpropane triacrylate, pentaerythritol triacrylate or one or more combinations thereof; the molecular weight of the second acrylate polymer is in the range of 60,000 to 600,000, and the second acrylate polymer contains polar groups, and the polar groups include a combination of one or more of hydroxyl, carboxyl, methylol, cyano, amino, amide, nitro, aldehyde, ketone, ester, and sulfonic acid groups.

[0012] Preferably, the catalyst is selected from a combination of one or more of p-toluenesulfonic acid, zinc chloride, pyridinium p-toluenesulfonate, sulfuric acid, phosphotungstic acid, cesium phosphotungstic acid, silicotungstic acid, zirconium oxide sulfate, tetraisopropoxytitanium, and dodecylbenzenesulfonic acid; and / or the first solvent and the second solvent are each independently selected from acetone, butanone, methyl ethyl ketone, cyclohexanone, cyclopentanone, methyl isobutyl ketone, isophorone, N-methylpyrrolidone, dioxane, tetrahydrofuran, ether, anisole, diethyl ether, propylene glycol methyl ether, n-hexane, heptane, cyclohexane, cyclopentanone, methyl isobutyl ketone, isophorone, N-methylpyrrolidone, dioxane, tetrahydrofuran, ethyl ether, anisole, diethyl ether, propylene glycol methyl ether, n-hexane, heptane, cyclohexane, cyclopentanone, cyclopentanone, methyl isobutyl ketone, isophorone, N-methylpyrrolidone, dioxane, tetrahydrofuran, ethyl ether, anisole, diethyl ether, propylene glycol methyl ether, n-hexane, A combination of one or more of pentane, toluene, xylene, dichloromethane, dichloroethane, dichlorobenzene, chlorotoluene, ethyl acetate, butyl acetate, propylene glycol methyl ether acetate, water, ethanol, n-butanol, sec-butanol, isopropyl alcohol, cyclohexanol, dimethyl sulfoxide, diethyl sulfoxide, benzylphenyl sulfoxide, dimethylformamide, dimethylacetamide, etc.; and / or the second silane coupling agent is selected from the group consisting of γ-aminopropyltriethoxysilane, N-(β-aminoethyl)-γ-aminopropyltrimethoxy(ethyl)oxysilane, γ-glycidyloxypropyltrimethoxysilane, γ-glycidyloxypropylmethyldiethoxysilane, vinyltriethoxysilane, γ-isocyanatepropyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-aminopropyltriethoxysilane, and trimethoxysilane; and / or the leveling agent is selected from the group consisting of one or more of acrylics, silicones, and fluorides.

[0013] According to the second aspect of the present application, a method for preparing a phase difference film is provided, comprising: a) providing a substrate; applying the first composition according to the first aspect of the present application on the substrate to form a photo-alignment layer; and b) applying the second composition according to the first aspect of the present application on the photo-alignment layer to form a liquid crystal layer, thereby preparing a phase difference film comprising a substrate, a photo-alignment layer and a liquid crystal layer.

[0014] The method of coating the first composition on the substrate to form a photo-alignment layer further comprises: a1) heating and drying the film after coating the first composition on the substrate, wherein the heating and drying temperature is 30-250°C, preferably 50-120°C, and the heating time is 0.5-10 minutes, preferably 0.5-5 minutes; a2) curing the dried film with ultraviolet light in an N2 atmosphere to obtain a photo-alignment layer. The N2 concentration is 30%-99.999%, preferably 70%-99.999%. The ultraviolet (UV) light irradiation energy is 10mJ / cm 2 -1000mJ / cm 2 , preferably 50-1000mJ / cm 2 .

[0015] The method of coating the second composition on the photo-alignment layer to form a liquid crystal layer further comprises: b1) heating and drying the film after coating the second composition on the photo-alignment layer, wherein the heating and drying temperature is 30-250°C, preferably 50-120°C, and the heating time is 0.5-10 minutes, preferably 0.5-5 minutes; b2) curing the dried film with ultraviolet light in an N2 atmosphere to obtain a liquid crystal layer. The N2 concentration is 30%-99.999%, preferably 70%-99.999%. The ultraviolet (UV) light irradiation energy is 10mJ / cm 2 -1000mJ / cm 2 , preferably 50-1000mJ / cm 2 .

[0016] Preferably, the liquid crystal molecules in the liquid crystal layer are vertically aligned.

[0017] Preferably, the peeling force between the photo-alignment layer and the liquid crystal layer, and between the photo-alignment layer and the substrate can be controlled. During peeling, a 3M tape or adhesive Tac is attached to the liquid crystal layer. The 3M tape or adhesive Tac is peeled off. Depending on the material adhered to the 3M tape or adhesive Tac, the following five peeling conditions can be achieved: 1) The peeling force between the photo-alignment layer and the liquid crystal layer is greater than the peeling force between the substrate and the photo-alignment layer. The photo-alignment layer and the liquid crystal layer cannot be peeled off using 3M tape or adhesive Tac. 2) The peeling force between the photo-alignment layer and the liquid crystal layer is greater than the peeling force between the substrate and the photo-alignment layer. The photo-alignment layer and the liquid crystal layer can be peeled off with 3M tape or Tac tape. 3) The peeling force between substrate and photo-alignment layer is greater than the peeling force between photo-alignment layer and liquid crystal layer. The substrate and photo-alignment layer cannot be peeled off using 3M tape or adhesive Tac. 4) The peeling force between substrate and photo-alignment layer is greater than the peeling force between photo-alignment layer and liquid crystal layer. The substrate and photo-alignment layer can be peeled off with 3M tape or Tac tape. 5) The adhesion between the substrate, photo-alignment layer and liquid crystal layer is greater than the adhesion between the 3M tape and the liquid crystal layer, and the substrate, photo-alignment layer and liquid crystal layer cannot be peeled off using 3M tape or adhesive Tac.

[0018] The technical solution adopted by the present invention can achieve the following beneficial effects: According to the formula and preparation process of the photo-alignment layer and the liquid crystal layer in the phase difference film provided by the present invention, the peeling between the layers of the liquid crystal phase difference film (including the peeling between the photo-alignment layer and the liquid crystal layer, and the peeling between the substrate layer, the photo-alignment layer and the liquid crystal layer) is controllable, which can meet the different lamination process requirements of panel manufacturers. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Schematic diagram of the structure of the liquid crystal phase difference film according to the present invention.

[0020] The following are the descriptions of the reference numerals: 100: Base material (S) 200: Photo-alignment layer (P) 300: Liquid crystal layer (RM) DETAILED DESCRIPTION To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0021] It should be noted that in this application, in order to distinguish the substances in the formula solution used to prepare the photo-alignment layer and the liquid crystal layer, this application uses the terms "first" and "second". The "first" and "second" are merely used to distinguish the substances and do not compare or rank the properties of the substances. For example, the first high-etherification-degree low-molecular-weight resin refers to a low-molecular-weight resin with a high degree of etherification (i.e., "high degree of etherification" means that the degree of etherification is generally required to be above 5.23) in the first composition used to prepare the photo-alignment layer, and the second high-etherification-degree low-molecular-weight resin refers to a low-molecular-weight resin with a high degree of etherification (i.e., "high degree of etherification" means that the degree of etherification is generally required to be above 5.23) in the second composition used to prepare the liquid crystal layer. The first high-etherification-degree low-molecular-weight resin and the second high-etherification-degree low-molecular-weight resin may be the same or different. Similarly, the first multifunctional low molecular weight resin refers to a low molecular weight resin containing two or more functional groups (i.e., "multifunctional" means "containing two or more functional groups") in the first composition used to prepare the photo-alignment layer, and the second multifunctional low molecular weight resin refers to a low molecular weight resin containing two or more functional groups (i.e., "multifunctional" means "containing two or more functional groups") in the second composition used to prepare the liquid crystal layer, wherein the first multifunctional low molecular weight resin and the second multifunctional low molecular weight resin may be the same or different.

[0022] According to one embodiment of the present application, a phase difference film is provided, comprising a photo-alignment layer and a liquid crystal layer, wherein the photo-alignment layer is formed by polymerizing a first composition, and the liquid crystal layer is formed by polymerizing a second composition; the formula of the first composition comprises: a first high-etherification-degree low-molecular-weight resin, a first multifunctional low-molecular-weight resin, a first silane coupling agent, and a first acrylate polymer; the formula of the second composition comprises: a second high-etherification-degree low-molecular-weight resin, a second multifunctional low-molecular-weight resin, and a second acrylate polymer; wherein the first high-etherification-degree low-molecular-weight resin has an etherification degree of 5.23 or more and a molecular weight of less than 5000 g / mol, and the first multifunctional ... The resin has two or more reactive functional groups and a molecular weight of less than 5000 g / mol, and the functional groups in the first multifunctional low molecular weight resin are selected from a combination of two or more of hydroxyl groups, acrylate groups, ethoxy groups, and methacrylate groups; wherein the second high etherification degree low molecular weight resin has an etherification degree of 5.23 or more and a molecular weight of less than 5000 g / mol, and the second multifunctional low molecular weight resin has two or more reactive functional groups and a molecular weight of less than 5000 g / mol, and the functional groups in the second multifunctional low molecular weight resin are selected from a combination of two or more of hydroxyl groups, acrylate groups, ethoxy groups, and methacrylate groups.

[0023] In the aforementioned embodiments, the provided liquid crystal retardation film can regulate the peeling force between the photo-alignment layer and the liquid crystal layer, and between the photo-alignment layer and the substrate / substrate layer, maximizing the value of each layer. The photo-alignment layer contains a large number of polar groups, which have a high polarity with the liquid crystal molecules, thereby ensuring stable vertical alignment of the liquid crystal molecules.

[0024] Specifically, the first high-etherification-degree low-molecular-weight resin in the first composition has a viscosity of 3,000-10,000, is widely applicable to solvents, and has excellent leveling properties. The first high-etherification-degree low-molecular-weight resin used includes, but is not limited to, butylated melamine resin, melamine-formaldehyde resin, methylated urea-formaldehyde resin, highly methylated melamine-formaldehyde resin, n-butanol-etherified melamine resin, butanol-etherified urea-formaldehyde resin, isobutanol-etherified amino resin, catechol borate-etherified phenol-formaldehyde resin, dicyanophenyl-etherified phenol-biphenyl-phenol-formaldehyde resin, organoboron-modified bismaleimide resin, glycidyl-etherified bismaleimide resin, hexamethoxymethylmelamine resin, etc. One or more of the above-mentioned first high-etherification-degree low-molecular-weight resins can be selected and mixed for addition. In terms of mass fraction, the first high-etherification-degree low-molecular-weight resin accounts for 0.1%-5% of the total mass of the first composition. In actual processes, the proportion of the first high-etherification-degree low-molecular-weight resin in the first composition can be adjusted according to different stripping requirements. For example, the first high-etherification-degree low-molecular-weight resin accounts for 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5% of the total mass of the first composition, or any value therebetween. By adding the first high-etherification-degree low-molecular-weight resin and the second high-etherification-degree low-molecular-weight resin to the first composition and the second composition, respectively, the formed photo-alignment layer and liquid crystal layer have good toughness and strength, thereby preventing cracking during stripping.

[0025] The first multifunctional low molecular weight resin in the first composition includes, but is not limited to, trimethylolpropane triacrylate (TMPTA), polyethylene glycol acrylate (PEGDA), dipropylene glycol diacrylate (DPGDA), trimethylolpropane trimethacrylate (TMPTMA), trimethylolpropane triacrylate (TMPTA), trimethylolpropane trimethacrylate (TMPTMA), ethoxylated glycerol triacrylate, dipentaerythritol penta / hexaacrylate (DPHA), dimethylolpropionic acid diacrylate (DMPA), ethoxylated trimethylolpropane triacrylate (EM2380-TF), pentaerythritol triacrylate (EM235), and trimethylolpropane triacrylate (EM231-TF). One or more of the above first multifunctional low molecular weight resins can be selected and used in combination. In terms of mass fraction, the first multifunctional low molecular weight resin accounts for 1%-5% of the total mass of the first composition. In actual processes, the proportion of the first multifunctional low molecular weight resin in the first composition can be adjusted according to different stripping requirements. For example, the first multifunctional low molecular weight resin accounts for 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5% of the total mass of the first composition, or any value in between. By adding the first multifunctional low molecular weight resin to the first composition for preparing the photo-alignment layer, the first multifunctional low molecular weight resin is cross-linked through a photocuring reaction to form a photo-alignment layer having a three-dimensional polymeric network structure, which has good thermal stability and chemical resistance.

[0026] When preparing a retardation film, the first silane coupling agent in the first composition accumulates on the surface of the photo-alignment layer during the drying process. When the second composition used to prepare the liquid crystal layer is applied and cured, it reacts with the first silane coupling agent to form a chemical bond. Furthermore, the interlayer adhesion can be controlled by adjusting the ratio. The first silane coupling agent is added to the first composition used to prepare the photo-alignment layer. During the drying process, the first silane coupling agent accumulates on the surface of the photo-alignment layer. When the second composition used to prepare the liquid crystal layer is applied and cured, it chemically bonds with the first silane coupling agent. Furthermore, the interlayer adhesion can be controlled by adjusting the ratio of the first silane coupling agent. Optional first silane coupling agents include but are not limited to γ-aminopropyltriethoxysilane (KH-550), KH-792 (containing amino and imino groups), γ-glycidoxypropyltrimethoxysilane (KH560), γ-glycidoxypropylmethyldiethoxysilane (KBM-602), vinyltriethoxysilane (VTES), γ-isocyanatepropyltriethoxysilane (KBE-9007), γ-methacryloxypropyltrimethoxysilane (KH-570), γ-aminopropyltriethoxysilane (KBM-903), trimethoxysilane, etc. One or more of the above-mentioned first silane coupling agents may be mixed and added, wherein, by weight, the first silane coupling agent accounts for 0.1%-5% of the total weight of the first composition. In actual processes, the proportion of the first silane coupling agent in the first composition may be adjusted according to different stripping requirements, for example, the first silane coupling agent accounts for 0.1%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5% of the total weight of the first composition, or any value therebetween. Preferably, the first silane coupling agent accounts for 0.2%-0.7% of the total weight of the first composition, for example, the first silane coupling agent accounts for 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7% of the total weight of the first composition, or any value therebetween.

[0027] The first composition used to prepare the photo-alignment layer in the retardation film requires a first acrylate polymer (a high-molecular-weight acrylate polymer) with numerous polar groups on its side chains. This first acrylate polymer can be synthesized (synthesis methods can be found in CN 118703090 A and CN 117568049) or purchased commercially. The polar groups on the side chains include, but are not limited to, hydroxyl, carboxyl, hydroxymethyl, cyano, amino, amide, nitro, aldehyde, ketone, ester, and sulfonic acid groups, with hydroxyl and carboxyl groups being preferred. The presence of polar groups in this first acrylate polymer enables excellent vertical alignment of the liquid crystal molecules in the liquid crystal layer. Optionally, the first acrylate polymer comprises 0.15% to 30% of the total mass of the first composition, and its molecular weight is 60,000 to 600,000. In the actual process, the proportion of the first acrylate polymer in the first composition can be adjusted according to different stripping requirements. For example, the first acrylate polymer accounts for 0.15%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10%, 10.5%, 11%, 11.5%, 12%, 12.5%, 13% of the total mass of the first composition. , 13.5%, 14%, 14.5%, 15%, 15.5%, 16%, 16.5%, 17%, 17.5%, 18%, 18.5%, 19%, 19.5%, 20%, 20.5%, 21%, 21.5%, 22%, 22.5%, 23%, 23.5%, 24%, 24.5%, 25%, 25.5%, 26%, 26.5%, 27%, 27.5%, 28%, 28.5%, 29%, 29.5%, 30% or any value in between.

[0028] The second composition used to prepare the liquid crystal layer includes a second high-etherification low-molecular-weight resin, which includes but is not limited to butylated melamine resin, melamine formaldehyde resin, methylated urea-formaldehyde resin, highly methylated melamine formaldehyde resin, n-butanol-etherified melamine resin, butanol-etherified urea-formaldehyde resin, isobutanol-etherified amino resin, catechol borate-etherified phenol-formaldehyde resin, dicyanophenyl-etherified phenol-biphenyl-phenol-formaldehyde resin, organoboron-modified bismaleimide resin, glycidyl-etherified bismaleimide resin, hexamethoxymethylmelamine resin, etc. One or more of the above-mentioned second high-etherification low-molecular-weight resins can be used in combination, and can be the same as or different from the second high-etherification low-molecular-weight resin selected in the first composition for preparing the photo-alignment layer. In terms of mass fraction, the second high etherification degree, low molecular weight resin accounts for 0.01%-10% of the total mass of the second composition; in the actual process, the proportion of the second high etherification degree, low molecular weight resin in the second composition can be adjusted according to different stripping requirements. For example, the second high etherification degree, low molecular weight resin accounts for 0.01%, 0.02%, 0.05%, 0.1%, 0.3%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10% of the total mass of the second composition, or any value between these values; preferably, the second high etherification degree, low molecular weight resin accounts for 0.02%-3.00% of the total mass of the second composition.

[0029] The second multifunctional low molecular weight resin in the second composition for preparing the liquid crystal layer includes, but is not limited to, trimethylolpropane triacrylate (TMPTA), polyethylene glycol acrylate (PEGDA), dipropylene glycol diacrylate (DPGDA), trimethylolpropane trimethacrylate (TMPTMA), trimethylolpropane triacrylate (TMPTA), trimethylolpropane trimethacrylate (TMPTMA), ethoxylated glycerol triacrylate, dipentaerythritol penta / hexaacrylate (DPHA), dimethylolpropionic acid diacrylate (DMPA), ethoxylated trimethylolpropane triacrylate (EM2380-TF), pentaerythritol triacrylate (EM235), trimethylolpropane triacrylate (EM231-TF), etc. It can be one low molecular weight resin or a mixture of multiple resins. The second multifunctional low molecular weight resin can be the same as or different from the first multifunctional low molecular weight resin used in the photo-alignment layer. The second multifunctional low molecular weight resin comprises 0.01% to 2.00% by mass of the total mass of the second composition. In actual processes, the proportion of the second multifunctional low molecular weight resin in the second composition can be adjusted according to different stripping requirements. For example, the second multifunctional low molecular weight resin may comprise 0.01%, 0.02%, 0.04%, 0.05%, 0.1%, 0.15%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.25%, 1.5%, 1.75%, 2%, or any value therebetween, of the total mass of the second composition. Preferably, the second multifunctional low molecular weight resin comprises 0.2% to 1.00% by mass of the total mass of the second composition. The second multifunctional low molecular weight resin can effectively copolymerize with other monomers in the liquid crystal layer, improving the heat resistance and chemical resistance of the liquid crystal layer and the interlayer adhesion between the liquid crystal layer and the photo-alignment layer.

[0030] The second composition for preparing the liquid crystal layer also includes a second acrylate polymer (a high molecular weight acrylate polymer). The acrylate polymer has cross-linking reaction sites on the long chain or branched chain, so that the vertical liquid crystal phase difference film forms a network structure and forms a chemical bond of a certain strength between the optical alignment layer and the liquid crystal layer to ensure the stability of the vertical orientation of the liquid crystal molecules. The second acrylate polymer can be the same as the acrylate polymer in the above-mentioned optical alignment layer, or it can be a mixture of multiple different acrylate polymers. In terms of mass fraction, the second acrylate polymer accounts for 0.1%-30% of the total mass of the second composition; in the actual process, the proportion of the second acrylate polymer in the second composition can be adjusted according to different stripping requirements. For example, the second acrylate polymer accounts for 0.1%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10%, 10.5%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, 45%, 50%, 51%, 52%, 53%, 54%, 55%, 56%, 57%, 58%, 59%, 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, 70 %, 15.5%, 16%, 16.5%, 17%, 17.5%, 18%, 18.5%, 19%, 19.5%, 20%, 20.5%, 21%, 21.5%, 22%, 22.5%, 23%, 23.5%, 24%, 24.5%, 25%, 25.5%, 26%, 26.5%, 27%, 27.5%, 28%, 28.5%, 29%, 29.5%, 30%, or any value therebetween. More preferably, the second acrylate polymer comprises 1% to 20% of the total weight of the second composition.

[0031] In another embodiment, the first composition used to prepare the photo-alignment layer further includes a photoinitiator. The photoinitiator can be a cleavage-type free radical photoinitiator, an oxime ester photoinitiator, or a hydrogen abstraction-type free radical photoinitiator. One or more types of photoinitiators can be mixed and used. By mass fraction, the photoinitiator accounts for 0.01% to 10% of the total mass of the first composition. In actual processes, the proportion of the photoinitiator can be adjusted according to the desired effect. For example, the photoinitiator accounts for 0.01%, 0.05%, 0.1%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10% of the total mass of the first composition, or any value therebetween. Preferably, the photoinitiator accounts for 0.3% to 5% of the total mass of the first composition.

[0032] In another embodiment, the first composition used to prepare the photo-alignment layer may further include a catalyst to accelerate esterification, etherification, or transesterification reactions in the first composition. For example, the catalyst may be selected from p-toluenesulfonic acid (PTSA), zinc chloride, pyridinium p-toluenesulfonate, sulfuric acid, phosphotungstic acid, cesium phosphotungstate (Cs-PW), silicotungstic acid, zirconium oxysulfate, tetraisopropoxytitanium, dodecylbenzenesulfonic acid, and the like. One or more of these catalysts may be mixed, with the catalyst comprising 0.1% to 10% of the total mass of the first composition. In actual processes, the catalyst percentage may be adjusted based on the desired effect, for example, 0.1%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10%, or any value therebetween. Preferably, the catalyst comprises 1% to 5% of the total mass of the first composition.

[0033] In one embodiment, the first composition for preparing the photo-alignment layer may further comprise a first solvent, and the optional first solvent includes but is not limited to ketones (such as acetone, butanone, methyl ethyl ketone, cyclohexanone, cyclopentanone, methyl isobutyl ketone, isophorone, N-methylpyrrolidone, etc.); ethers (such as dioxane, tetrahydrofuran, ethyl ether, anisole, diethyl ether, propylene glycol methyl ether (PGME), etc.); aliphatic hydrocarbons (such as n-hexane, heptane, isoparaffins, etc.); cyclic hydrocarbons Aromatic hydrocarbons (such as toluene, xylene, etc.); halogenated carbons (such as dichloromethane, dichloroethane, dichlorobenzene, chlorotoluene, etc.); esters (such as ethyl acetate, butyl acetate, propylene glycol methyl ether acetate (PGMEA)), water, alcohols (such as ethanol, n-butanol, sec-butanol, isopropanol, cyclohexanol, etc.); sulfoxides (such as dimethyl sulfoxide, diethyl sulfoxide, benzylphenyl sulfoxide, etc.); amides (such as dimethylformamide, dimethyl acetamide, etc.), and one or more of the above solvents can be mixed. In terms of mass fraction, the first solvent accounts for 50%-95% of the total mass of the first composition. In actual applications, the amount of the first solvent can be adjusted according to demand. For example, the first solvent can account for 50%, 51%, 52%, 53%, 54%, 55%, 56%, 57%, 58%, 59%, 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, and 95% of the total mass of the first composition. Preferably, the first solvent can account for 70%-95% of the total mass of the first composition.

[0034] In one embodiment, the second composition may include a polymerizable liquid crystal composition. The polymerizable liquid crystal composition may be synthesized in-house or purchased commercially. It only needs to have a polar group at one end of the liquid crystal molecules in the polymerizable liquid crystal composition. The liquid crystal molecules with polar groups exhibit strong polar repulsion with the photo-alignment layer, inducing vertical alignment of the liquid crystal molecules. The polar groups include, but are not limited to, hydroxyl groups, carboxyl groups, hydroxymethyl groups, cyano groups, amino groups, amide groups, nitro groups, aldehyde groups, ketone groups, ester groups, and sulfonic acid groups, with hydroxyl groups and carboxyl groups being preferred. In terms of mass fraction, the polymerizable liquid crystal composition accounts for 1.5%-45% of the total mass of the second composition; in the actual process, the proportion of the polymerizable liquid crystal composition in the second composition can be adjusted according to different stripping requirements. For example, the polymerizable liquid crystal composition accounts for 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10%, 10.5%, 11%, 11.5%, 12%, 12.5%, 13%, 13.5%, 14%, 14.5%, 15%, 15.5%, 16%, 16.5%, 17%, 17.5%, 18%, 18.5%, 19%, 19.5% of the total mass of the second composition. , 20.5%, 21%, 21.5%, 22%, 22.5%, 23%, 23.5%, 24%, 24.5%, 25%, 25.5%, 26%, 26.5%, 27%, 27.5%, 28%, 28.5%, 29%, 29.5%, 30%, 30.5%, 31%, 31.5%, 32%, 32.5%, 33%, 33.5%, 34%, 34.5%, 35%, 35.5%, 36%, 36.5%, 37%, 37.5%, 38%, 38.5%, 39%, 39.5%, 40%, 40.5%, 41%, 41.5%, 42%, 42.5%, 43%, 43.5%, 44%, 44.5%, 45%, or any value therebetween. Preferably, the polymerizable liquid crystal composition accounts for 2.5%-45% of the total mass of the second composition.

[0035] In one embodiment, the second composition may also include a second silane coupling agent. The interlayer adhesion can be further controlled by adjusting the ratio of the second silane coupling agent in the second composition. Optional second silane coupling agents include, but are not limited to, γ-aminopropyltriethoxysilane (KH-550), KH-792 (containing amino and imino groups), γ-glycidoxypropyltrimethoxysilane (KH560), γ-glycidoxypropylmethyldiethoxysilane (KBM-602), vinyltriethoxysilane (VTES), γ-isocyanatepropyltriethoxysilane (KBE-9007), γ-methacryloxypropyltrimethoxysilane (KH-570), γ-aminopropyltriethoxysilane (KBM-903), and trimethoxysilane. One or more of the above-mentioned second silane coupling agents can be mixed and added, and the second silane coupling agent accounts for 0-5% of the total mass of the second composition by mass. Since the first silane coupling agent has already been added to the first composition, the second silane coupling agent may not be added to the second composition. Of course, the proportion of the second silane coupling agent in the second composition can also be adjusted according to different stripping requirements. For example, the second silane coupling agent accounts for 0%, 0.1%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5% of the total mass of the second composition, or any value in between.

[0036] In one embodiment, the second composition used to prepare the liquid crystal layer may further include a photoinitiator. The photoinitiator may be a cleavage-type free radical photoinitiator, an oxime ester photoinitiator, or a hydrogen abstraction-type free radical photoinitiator. One or more types of photoinitiators may be mixed and used. By mass fraction, the photoinitiator comprises 0.01% to 10% of the total mass of the liquid crystal layer composition. The selected photoinitiator may be the same as or different from the photoinitiator in the photo-alignment layer. In actual processes, the proportion of the photoinitiator can be adjusted based on the desired effect. For example, the photoinitiator may comprise 0.01%, 0.05%, 0.1%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10% of the total mass of the liquid crystal layer composition, or any value therebetween. Preferably, the photoinitiator comprises 0.3% to 5% of the total mass of the liquid crystal layer composition.

[0037] The second composition used to prepare the liquid crystal layer may also include a leveling agent. This agent helps the second composition coating form a smooth, uniform coating during drying, adjusts the surface tension of the second composition solution, and improves the leveling properties of the second composition solution. Leveling agents can be categorized as acrylic, silicone, and fluoride. One type or a combination of multiple types can be used. Among them, acrylic and silicone leveling agents are preferred. Calculated by mass, the leveling agent accounts for 0.01%-5% of the total mass of the second composition. Different amounts of the leveling agent can be added according to process requirements. For example, the leveling agent accounts for 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.1%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5% or any value therebetween of the total mass of the second composition. Preferably, the leveling agent accounts for 0.1%-1.0% of the total mass of the second composition.

[0038] In one embodiment, the second composition for preparing the liquid crystal layer may further include a second solvent, and the optional second solvent includes but is not limited to ketones (such as acetone, butanone, methyl ethyl ketone, cyclohexanone, cyclopentanone, methyl isobutyl ketone, isophorone, N-methylpyrrolidone, etc.); ethers (such as dioxane, tetrahydrofuran, ethyl ether, anisole, diethyl ether, propylene glycol methyl ether (PGME), etc.); aliphatic hydrocarbons (such as n-hexane, heptane, isoparaffins, etc.); cyclic hydrocarbons. (such as cyclohexane, cyclopentane, etc.); aromatic hydrocarbons (such as toluene, xylene, etc.); halogenated carbons (such as dichloromethane, dichloroethane, dichlorobenzene, chlorotoluene, etc.); esters (such as ethyl acetate, butyl acetate, propylene glycol methyl ether acetate (PGMEA)), water, alcohols (such as ethanol, n-butanol, sec-butanol, isopropanol, cyclohexanol, etc.); sulfoxides (such as dimethyl sulfoxide, diethyl sulfoxide, benzylphenyl sulfoxide, etc.); amides (such as dimethylformamide, dimethyl acetamide, etc.), and one or more of the above solvents can be mixed. In terms of mass fraction, the second solvent accounts for 50%-95% of the total mass of the second composition. In actual applications, the amount of the second solvent can be adjusted as needed. For example, the second solvent can account for 50%, 51%, 52%, 53%, 54%, 55%, 56%, 57%, 58%, 59%, 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, or 95% of the total mass of the second composition. Preferably, the second solvent can account for 70%-95% of the total mass of the second composition.

[0039] In one embodiment, the present application provides a method for preparing a phase difference film, comprising: providing a substrate; coating the above-mentioned first composition on the substrate to form a photo-alignment layer; and coating the above-mentioned second composition on the photo-alignment layer to form a liquid crystal layer.

[0040] [Photo-alignment layer] The photoalignment layer forms a directional microstructure through photochemical action, guiding the molecular alignment of the subsequent liquid crystal layer. Compared to traditional rubbing methods, photoalignment requires no physical contact, avoiding dust and static electricity issues, making it particularly suitable for the manufacture of high-precision optical devices such as flexible displays. The photoalignment layer provides a strong polar orientation for the liquid crystal molecules, causing them to align vertically under the influence of the polarity of the photoalignment layer. In other words, the photoalignment layer, applied to a smooth, flat substrate, possesses a strong polarity, creating a sufficient polar repulsion with one end of the liquid crystal molecules subsequently coated on the photoalignment layer, forcing the liquid crystal molecules to align vertically.

[0041] In the above embodiment, the photo-alignment layer is obtained by uniformly coating the first composition (hereinafter referred to as the photo-alignment layer solution) on the substrate and drying and curing it.

[0042] Specifically, the method for preparing the photo-alignment layer includes the following steps: Step 1: Apply the prepared photo-alignment layer solution onto a substrate. The substrate can be an organic substrate (e.g., cellulose polymers, polymethyl methacrylate and lactone ring-containing polymers, acrylic polymers such as acrylate polymers, thermoplastic norbornene polymers, polycarbonate polymers, polyester polymers such as polyethylene terephthalate and polyethylene naphthalate, styrene polymers such as polystyrene and acrylonitrile-styrene copolymers, polyolefin polymers such as polyethylene, polypropylene, and ethylene-propylene copolymers, vinyl chloride polymers, amide polymers such as nylon and aromatic polyamides, imide polymers, sulfone polymers, polyethersulfone polymers, polyetheretherketone polymers, polyphenylene sulfide polymers, vinylidene chloride polymers, vinyl alcohol polymers, vinyl butyral polymers, aromatic ester polymers, polyoxymethylene polymers, epoxy polymers, etc.), or an inorganic substrate (e.g., glass substrate). Organic substrates are preferred, and the substrate transmittance must be greater than 60%, preferably greater than 80%. The substrate needs to have a certain degree of heat resistance to prevent deformation during the subsequent coating and drying process of the photo-alignment layer solution. Furthermore, the substrate needs to be stable, protected from solvent erosion, and maintain good chemical resistance.

[0043] Step 2: Place the coated film in an oven for heating and drying to remove the solvent in the photo-alignment layer solution (i.e., the first solvent in the first composition). The heating and drying temperature is 30-250°C, preferably 50-120°C, and the heating time is 0.5-10 minutes, preferably 0.5-5 minutes.

[0044] Step 3: Place the dried film in an N2 atmosphere and use a certain energy of UV light to irradiate and cure to obtain a photo-alignment layer film. The concentration of N2 is 30%-99.999%, preferably 70%-99.999%. Irradiate with a certain energy of UV light to obtain a photo-alignment layer film. The irradiation energy of UV light can be selected as 10mJ / cm 2 -1000mJ / cm 2 , preferably 50-1000mJ / cm 2 .

[0045] [Liquid crystal layer] The liquid crystal layer is formed by photocuring or thermally curing polymerizable liquid crystal monomers (such as liquid crystal polymers or cross-linked compounds) in a polymerizable liquid crystal composition. The molecules align along the orientation provided by the photo-alignment layer, creating a birefringence effect that introduces retardation. The thickness of the liquid crystal layer and the molecular alignment angle (such as vertical or twisted nematic) directly influence the magnitude and type of retardation. By stacking liquid crystal layers with different orientations, wide viewing angle compensation and dispersion control can be achieved, meeting the requirements of OLED or high-contrast displays.

[0046] The liquid crystal layer is formed by uniformly coating the second composition (hereinafter referred to as the liquid crystal layer solution) on the photo-alignment layer, drying in a hot air oven to remove the solvent, and then curing with ultraviolet light to form a phase difference film.

[0047] Preparation method of liquid crystal layer: Step 1: Evenly coat the liquid crystal layer solution on the photo-alignment layer film and heat it in a hot air oven for a specified period of time until the solvent (i.e., the second solvent in the second composition) has completely evaporated. The heating and drying process is performed at a temperature of 30-250°C, preferably 50-120°C, for a heating time of 0.5-10 minutes, preferably 0.5-5 minutes.

[0048] Step 2: Place the dried film in an N2 atmosphere and use UV light of a certain energy to cure it to obtain a liquid crystal layer film. The concentration of N2 is 30%-99.999%, preferably 90%-99.999%. Irradiate with a certain energy of UV light to obtain a liquid crystal layer. The UV light energy can be 10mJ / cm 2 -2000mJ / cm 2 , preferably 200-1200mJ / cm 2 .

[0049] In one embodiment, a retardation film prepared by the above-described preparation method is provided. The retardation film exhibits vertical alignment (VA) of the liquid crystal molecules, characterized by the long axis (optical axis) of the liquid crystal molecules being perpendicular to the substrate surface. This allows the liquid crystal molecules to form an angle of approximately 90° with the substrate when stationary, resulting in a unique alignment. This alignment can be used to determine the VA state of the liquid crystals by measuring the pretilt angle of the liquid crystal layer. The pretilt angle of a qualified liquid crystal alignment film according to the present invention is ±90.00 ± 0.5°.

[0050] In this application, the peeling force between the photo-alignment layer and the liquid crystal layer, and between the photo-alignment layer and the substrate can be adjusted to maximize the value of each layer. This application can adjust the adhesion of each layer according to the needs of use to achieve different peeling combination effects. Figure 1This is a schematic diagram of the structure of the retardation film of the present invention. 3M tape or adhesive Tac is used as a peeling tool. The 3M tape or adhesive Tac is applied evenly to the liquid crystal layer (avoiding bubbles and wrinkles during application). The 3M tape or adhesive Tac is removed, and the peeling condition between the layers of the retardation film is determined by the substance adhered to the 3M tape or adhesive Tac. Five peeling conditions can be achieved based on customer needs: 1) The peeling force between the photo-alignment layer and the liquid crystal layer is greater than the peeling force between the substrate and the photo-alignment layer. The photo-alignment layer and the liquid crystal layer cannot be peeled off using 3M tape or adhesive Tac. 2) The peeling force between the photo-alignment layer and the liquid crystal layer is greater than the peeling force between the substrate and the photo-alignment layer. The photo-alignment layer and the liquid crystal layer can be peeled off with 3M tape or Tac tape. 3) The peeling force between substrate and photo-alignment layer is greater than the peeling force between photo-alignment layer and liquid crystal layer. The substrate and photo-alignment layer cannot be peeled off using 3M tape or adhesive Tac. 4) The peeling force between substrate and photo-alignment layer is greater than the peeling force between photo-alignment layer and liquid crystal layer. The substrate and photo-alignment layer can be peeled off with 3M tape or Tac tape. 5) The adhesion between the substrate, photo-alignment layer and liquid crystal layer is greater than the adhesion between the 3M tape and the liquid crystal layer. The substrate, photo-alignment layer and liquid crystal layer cannot be peeled off using 3M tape or adhesive Tac.

[0051] Among the five peeling scenarios described above, peelable means that the adhesion between the liquid crystal layer and the photo alignment layer or between the photo alignment layer and the substrate layer is less than the adhesion provided by 3M tape or adhesive Tac, meaning the two layers can be separated using 3M tape or adhesive Tac. Non-peelable means that the adhesion between the liquid crystal layer and the photo alignment layer or between the photo alignment layer and the substrate layer is greater than the adhesion provided by 3M tape or adhesive Tac, meaning the two layers cannot be separated using 3M tape or adhesive Tac.

[0052] Therefore, in this application, the adhesion between the substrate, the photo-alignment layer and the liquid crystal layer is adjusted by adjusting the formulation of the photo-alignment layer and the liquid crystal layer to achieve different peeling conditions to meet the usage requirements of different customers.

[0053] The retardation film provided by the present invention is further described below with reference to the following examples. The ingredients and raw materials mentioned in these examples were obtained through conventional routes or prepared by methods known in the art and comply with relevant national standards. The polymerizable liquid crystal compositions used in the following examples were all products from Merck. The acrylate polymer used in Examples S1 and S2 was ACRYSET BPF307 from Nippon Shokubai.

[0054] Example 1 A phase difference film capable of achieving delamination and peeling is prepared by the following steps: S1: Acrylate polymer (100 parts by mass), KH-550 (2 parts by mass), hexamethoxymethyl melamine resin (SC-A03, 2 parts by mass), photoinitiator 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]-ethanone 1-(O-acetoxime) (OXE-2, 5 parts by mass), ethoxylated trimethylolpropane triacrylate (EM2380-TF, 10 parts by mass), p-toluenesulfonic acid (PTSA, 2 parts by mass), N-methylpyrrolidone (NMP, 150 parts by mass), ethanol (100 parts by mass), butanone (150 parts by mass), and dissolved in a 40°C water bath with stirring for 60 minutes to obtain a photo-alignment layer solution. The photo-alignment layer solution was evenly coated on the substrate using a wire rod (#30 micron), dried in a blast oven at 70°C for 60 seconds, and heated with an energy of 600 mJ / cm2 in an N2 atmosphere with an O2 concentration not higher than 100 ppm. 2 The photo-alignment layer is cured by ultraviolet light to obtain a photo-alignment layer.

[0055] S2: A polymerizable liquid crystal composition 2296 (Merck, commercially available) (75 parts by mass), pentaerythritol triacrylate (EM235, 2 parts by mass), an acrylate polymer (20 parts by mass), hexamethoxymethyl melamine resin (SC-A03, 1 part by mass), OXE-02 (3 parts by mass), BYK-LPG 20901 (1 part by mass), toluene (450 parts by mass), and propylene glycol methyl ether acetate (PGMEA, 150 parts by mass) were heated in a 45°C water bath and stirred for 60 minutes to obtain a liquid crystal layer solution. The liquid crystal layer solution was evenly coated on the photoalignment layer using a wire rod (#20 micron), dried in a forced air oven at 80°C for 120 seconds, and then heated to an energy of 800 mJ / cm when the N2 concentration exceeded 99.99%. 2 The phase difference film is cured by ultraviolet light to obtain a phase difference film.

[0056] Example 2 A phase difference film capable of being delaminated and peeled is disclosed, which differs from Example 1 in that the solvent in S1 is replaced with ethanol (280 parts by mass) and methyl acrylate acetate (70 parts by mass), and another photoinitiator, ethyl 2,4,6-trimethylbenzoylphenylphosphonate (TPO-L, 5 parts by mass), is additionally added.

[0057] Example 3 A phase difference film capable of achieving delamination and peeling is provided, which differs from Example 1 in that KH-550 in S1 is replaced with trimethoxysilane propyl acrylate (20 parts by mass). Example 4 A phase difference film capable of being delaminated and peeled is provided, which differs from Example 1 in that the drying temperature in S1 is increased from 70° C. to 100° C., and the mass fraction of the acrylate polymer is changed to 2 mass parts.

[0058] Example 5 A phase difference film capable of achieving layered peeling is provided, which differs from Example 1 in that the heating time in S1 is increased from 1 min to 5 min.

[0059] Example 6 A phase difference film capable of achieving delamination and peeling is provided, wherein the difference between the phase difference film and Example 1 is that the mass fraction of SC-A03 in S1 is changed to 20 mass fractions.

[0060] Example 7 A phase difference film capable of achieving delamination and peeling is provided, which differs from Example 1 in that the addition amount of SC-A03 in S1 and S2 is increased to 5 parts by mass.

[0061] Example 8 A phase difference film capable of being delaminated and peeled is disclosed, which differs from Example 2 in that SC-A03 in S1 is replaced with n-butanol etherified melamine resin; and the amount of the acrylate polymer added in S2 is increased to 100 parts by mass.

[0062] Example 9 A phase difference film capable of being delaminated and peeled is provided, which differs from Example 4 in that SC-A03 is replaced with n-butanol-etherified melamine resin (20 parts by mass) in S1 and S2.

[0063] Example 10 A phase difference film capable of achieving delamination and peeling is disclosed, which differs from Example 2 in that 5 parts by mass of EM231-TF are added to S1 and S2.

[0064] Example 11 A phase difference film capable of being delaminated and peeled is provided, which differs from Example 2 in that vinyl triethoxysilane is added to S1 and S2 in an amount equal to that of KH-550 in S1.

[0065] Example 12 A phase difference film capable of achieving delamination and peeling is provided, which differs from Example 5 in that the drying temperature in S2 is increased from 80°C to 100°C.

[0066] Example 13 A phase difference film capable of being delaminated and peeled is provided, which differs from Example 5 in that the solvent in S2 is replaced with PGMEA (400 parts by mass), cyclohexanone (400 parts by mass), and butanone (100 parts by mass).

[0067] Example 14 A phase difference film capable of achieving delamination and peeling, which differs from Example 8 in that the ultraviolet light irradiation energy in S2 is increased to 1200 mJ / cm 2 .

[0068] Comparative Example 1 A phase difference film that cannot be delaminated is prepared by the following steps: S1: The same acrylate polymer (100 parts by mass), KH-550 (3 parts by mass), TPO-L (5 parts by mass), OXE-02 (3 parts by mass), N-methylpyrrolidone (NMP, 150 parts by mass), ethanol (100 parts by mass), and butanone (150 parts by mass) as in Example 1 were used. The photo-alignment layer solution was dissolved in a 40°C water bath with stirring for 60 minutes. The photo-alignment layer solution was evenly coated on the substrate using a wire rod (#30 micron), dried in a 70°C oven for 60 seconds, and heated with an energy of 600 mJ / cm2 in an N2 atmosphere with an O2 concentration not higher than 100 ppm. 2 The photo-alignment layer is cured by ultraviolet light to obtain a photo-alignment layer.

[0069] S2: A polymerizable liquid crystal composition 2296 (Merck, commercially available) (75 parts by mass), pentaerythritol triacrylate (EM235, 2 parts by mass), BYK-LPG 20901 (leveling agent, 1 part by mass), OXE-02 (3 parts by mass), toluene (450 parts by mass), and PGMEA (propylene glycol methyl ether acetate, 450 parts by mass) were heated in a 45°C water bath and stirred for 60 minutes to obtain a liquid crystal layer solution. The liquid crystal layer solution was evenly coated on the photoalignment layer using a wire rod (#20 micron), dried in a forced air oven at 80°C for 120 seconds, and then heated with an energy of 800 mJ / cm2 at an N2 concentration exceeding 99.99%. 2 The phase difference film is cured by ultraviolet light to obtain a phase difference film.

[0070] Comparative Example 2 A phase difference film that cannot be delaminated is prepared by the following steps: S1: The same acrylate polymer (100 parts by mass), ethoxylated trimethylolpropane triacrylate (EM2380-TF, 2 parts by mass), ZnCl2 (3 parts by mass), OXE-02 (2 parts by mass), NMP (150 parts by mass), ethanol (100 parts by mass), and butanone (150 parts by mass) as in Example 1 were dissolved in a 40°C water bath with stirring for 60 minutes to obtain a photo-alignment layer solution. The photo-alignment layer solution was evenly coated on the substrate using a wire rod (#30 micron), dried in a 70°C oven for 60 seconds, and heated in an N2 atmosphere with an O2 concentration not higher than 100 ppm using an energy of 1000 mJ / cm 2 The photo-alignment layer is cured by ultraviolet light to obtain a photo-alignment layer.

[0071] S2: A liquid crystal layer solution was obtained by heating and stirring a polymerizable liquid crystal composition 2435 (Merck, commercially available) (75 parts by mass), EM235 (2 parts by mass), TPO-L (2 parts by mass), BYK-UV3535 (1 part by mass), toluene (450 parts by mass), and PGMEA (450 parts by mass) in a 45°C water bath for 60 minutes. The liquid crystal layer solution was evenly coated on the photo-alignment layer using a wire rod (#20 micron). After drying in a forced air oven at 80°C for 120 seconds, an energy of 1200 mJ / cm was used when the N2 concentration exceeded 99.99%. 2 The phase difference film is cured by ultraviolet light to obtain a phase difference film.

[0072] Comparative Example 3 S1: EM2380-TF (5 parts by mass), SC-A03 (10 parts by mass), TPO-L (3 parts by mass), NMP (150 parts by mass), ethanol (100 parts by mass), and butanone (150 parts by mass) were stirred and dissolved in a 40°C water bath for 60 minutes to obtain a photo-alignment layer solution. A wire rod (#30 micron) was used to evenly coat the photo-alignment layer solution on the substrate, dried in a 70°C oven for 60 seconds, and heated in an N2 atmosphere with an O2 concentration not exceeding 100 ppm using an energy of 1000 mJ / cm 2 The photo-alignment layer is cured by ultraviolet light to obtain a photo-alignment layer.

[0073] S2: A polymerizable liquid crystal composition 2435 (Merck, commercially available) (75 parts by mass), OXE-02 (5 parts by mass), 1-[4-(phenylthio)phenyl]-1,2-octanedione 2-(O-benzoyloxime) (OXE-01, 3 parts by mass), BYK-UV3535 (1 part by mass), toluene (450 parts by mass), and PGMEA (450 parts by mass) were heated in a 45°C water bath with stirring for 60 minutes to obtain a liquid crystal layer solution. The liquid crystal layer solution was evenly coated on the photoalignment layer using a wire rod (#20 micron), dried in a forced air oven at 80°C for 120 seconds, and then heated to an energy of 1200 mJ / cm when the N2 concentration exceeded 99.99%. 2 The phase difference film is cured by ultraviolet light to obtain a phase difference film.

[0074] Performance testing: ① Optical performance test: Use AxoScan (produced by Axometrics, USA) to test the pre-tilt angle (Pre Tilt), optical film thickness (d), and optical delay in the vertical direction of the film (i.e., the phase difference value in the Z-axis direction, Rth). Specifically, by inputting the average refractive index ((n x +n y +n z ) / 3) and film thickness (d (μm)), calculate Rth=(n z -(n x +n y ) / 2)×d.

[0075] ② Peel Force Test: Use the Peel Force Tensile Tester (Model: KJ-1065A) to measure the peel force between the retardation film layers. The test modes are 90° peel (tension direction perpendicular to the direction of movement) and 180° peel (tension direction parallel to the direction of movement). Apply 3M transparent tape to the liquid crystal layer and start the program according to the preset program. The system automatically records the peel force during peeling.

[0076] The optical performance test results of each embodiment and comparative example are shown in Table 1 below: Table 1: Optical properties of retardation films

[0077] As can be seen from Table 1, the liquid crystal molecules of the phase difference films in Examples 1-14 are all in vertical alignment (the pre-tilt angles are all close to 90 degrees), and the optical properties are good.

[0078] A peel force tensile tester was used to test the peeling condition and peeling force between the retardation film layers. The results are shown in Table 2. In Table 2, SP peeling represents peeling between the substrate and the photo-alignment layer, P-RM peeling represents peeling between the photo-alignment layer and the liquid crystal layer, and liquid crystal shedding indicates whether the liquid crystal layer is intact. For example, no liquid crystal shedding indicates that the liquid crystal layer is intact.

[0079] Table 2 Peeling situation and peeling force between retardation films

[0080] Table 2 shows that variations in the formulations and processes for the different liquid crystal layers and photo-alignment layers result in varying peeling behavior between the different layers of the retardation film, meeting the varying lamination process requirements of panel manufacturers. However, while the peeling results between the layers of the retardation films produced using different process formulations are the same, the peeling forces vary significantly. To further characterize the peeling force differences between the formulations, Table 3 below illustrates the peeling force magnitudes and ranges for different examples. The peeling force tests were conducted in both 90° and 180° directions. In Table 3, SP represents substrate-photo-alignment layer, and P-RM represents photo-alignment layer-liquid crystal layer.

[0081] Table 3 Peeling force of different phase difference films

[0082] It can be seen from Table 3 that the present invention achieves the desired effect.

[0083] Compared to Comparative Examples 1-2, the difference in peel force between the SP and P-RM films in Examples 1-14 is larger. This peel force can be adjusted through the formulation of the liquid crystal layer and the photo-alignment layer. This prevents panel manufacturers from being unable to effectively separate the layers of the retardation film during lamination, effectively achieving separation between the layers. A greater difference in peel force between the layers indicates a more complete separation of the layers during the separation process, thus avoiding incomplete peeling.

[0084] Examples 1, 2, and 4 achieved the good results of easy SP peeling, no P-RM separation, and no liquid crystal shedding. Examples 13 and 14 achieved the good results of SP peeling, P-RM peeling, and no liquid crystal shedding.

[0085] Comparing Example 1 with Example 2, it was found that changing the solvent in the photo-alignment layer solution had little effect on the peeling force. Comparing Example 2 with Example 8, it was found that replacing SC-A03 in S1 with n-butanol-etherified melamine resin resulted in the opposite peeling results for SP and P-RM. This is likely due to differences in their molecular structures and the preferential reaction sites. Comparing Example 14 with Example 8, it was found that varying the energy of UV irradiation also affected the interlayer peeling results. Comparing Example 13 with Example 5, it was found that adjusting the solvent and solvent ratio also affected the peeling results.

[0086] In summary, adjusting the formula of the optical alignment layer and the liquid crystal layer in combination with the corresponding process can better achieve the results required for different separations between the phase difference film layers and maximize the bonding effect.

[0087] The embodiments of the present application are described above in conjunction with the accompanying drawings, but the present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of this application, ordinary technicians in this field can also make many forms without departing from the purpose of this application and the scope of protection of the claims, all of which are within the protection of this application.

Claims

1. A phase difference film, characterized in that: The method comprises a photo-alignment layer and a liquid crystal layer, wherein the photo-alignment layer is formed by polymerizing a first composition, and the liquid crystal layer is formed by polymerizing a second composition; The first composition comprises: a first high-etherification-degree low-molecular-weight resin, a first multifunctional low-molecular-weight resin, a first silane coupling agent, and a first acrylate polymer; The second composition comprises: a second high-etherification-degree low-molecular-weight resin, a second multifunctional low-molecular-weight resin, and a second acrylate polymer; The first high-etherification-degree low-molecular-weight resin has a degree of etherification of 5.23 or greater and a molecular weight of less than 5000 g / mol, the first multifunctional low-molecular-weight resin has two or more reactive functional groups and a molecular weight of less than 5000 g / mol, and the functional groups in the first multifunctional low-molecular-weight resin are selected from a combination of two or more of hydroxyl groups, acrylate groups, ethoxy groups, and methacrylate groups; The second high-etherification-degree low-molecular-weight resin has a degree of etherification of 5.23 or more and a molecular weight of less than 5000 g / mol, the second multi-functional low-molecular-weight resin has two or more reactive functional groups and a molecular weight of less than 5000 g / mol, and the functional groups in the second multi-functional low-molecular-weight resin are selected from a combination of two or more of hydroxyl groups, acrylate groups, ethoxy groups, and methacrylate groups.

2. The phase difference film according to claim 1, wherein The first composition further comprises at least one of a photoinitiator, a catalyst, and a first solvent; and / or The second composition further includes a polymerizable liquid crystal composition, and the second composition further includes at least one of a second silane coupling agent, a leveling agent, and a second solvent.

3. The phase difference film according to claim 2, characterized in that Calculated by mass fraction, the first high-etherification-degree low-molecular-weight resin accounts for 0.1%-5% of the total mass of the first composition; and / or Calculated by mass fraction, the first multifunctional low molecular weight resin accounts for 1% to 5% of the total mass of the first composition; and / or In terms of mass fraction, the first silane coupling agent accounts for 0.1% to 5% of the total mass of the first composition; and / or Calculated by mass fraction, the first acrylate polymer accounts for 0.15% to 30% of the total mass of the first composition; and / or The photoinitiator accounts for 0.01% to 10% of the total mass of the first composition by mass; and / or The catalyst accounts for 0.1% to 10% of the total mass of the first composition by mass; and / or Calculated by mass fraction, the first solvent accounts for 50%-95% of the total mass of the first composition.

4. The phase difference film according to claim 2, wherein Calculated by mass fraction, the second high-etherification-degree low-molecular-weight resin accounts for 0.01%-10% of the total mass of the second composition; and / or The second multifunctional low molecular weight resin accounts for 0.01% to 2.00% of the total mass of the second composition by mass; and / or The polymerizable liquid crystal composition accounts for 1.5% to 45% of the total mass of the second composition by mass; and / or The second acrylate polymer accounts for 0.1% to 30% of the total mass of the second composition; and / or In terms of mass fraction, the second silane coupling agent accounts for 0-5% of the total mass of the second composition; and / or In terms of mass fraction, the leveling agent accounts for 0.01%-5% of the total mass of the second composition; and / or Calculated by mass fraction, the second solvent accounts for 50%-90% of the total mass of the second composition.

5. The phase difference film according to claim 1, wherein The first high-etherification-degree low-molecular-weight resin is selected from the group consisting of one or more combinations of butylated melamine resin, melamine formaldehyde resin, methylated urea-formaldehyde resin, high-methylated melamine formaldehyde resin, n-butanol-etherified melamine resin, butanol-etherified urea-formaldehyde resin, isobutanol-etherified amino resin, catechol borate-etherified phenol-formaldehyde resin, dicyanophenyl-etherified phenol-biphenyl-phenol-formaldehyde resin, organoboron-modified bismaleimide resin, glycidyl-etherified bismaleimide resin, and hexamethoxymethylmelamine resin; The first multifunctional low molecular weight resin is selected from the group consisting of trimethylolpropane triacrylate, polyethylene glycol acrylate, dipropylene glycol diacrylate, trimethylolpropane trimethacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, ethoxylated glycerol triacrylate, dipentaerythritol penta / hexaacrylate, dimethylolpropionic acid diacrylate, ethoxylated trimethylolpropane triacrylate, and pentaerythritol triacrylate. The first silane coupling agent is selected from the group consisting of γ-aminopropyltriethoxysilane, N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, γ-glycidyloxypropyltrimethoxysilane, γ-glycidyloxypropylmethyldiethoxysilane, vinyltriethoxysilane, γ-isocyanatepropyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-aminopropyltriethoxysilane, and a combination of one or more of trimethoxysilane; The molecular weight of the first acrylate polymer is in the range of 60,000 to 600,000, and the first acrylate polymer comprises polar groups, wherein the polar groups include one or more of hydroxyl groups, carboxyl groups, hydroxymethyl groups, cyano groups, amino groups, amide groups, nitro groups, aldehyde groups, ketone groups, ester groups, and sulfonic acid groups; The second high-etherification-degree low-molecular-weight resin is selected from the group consisting of one or more combinations of butylated melamine resin, melamine formaldehyde resin, methylated urea-formaldehyde resin, high-methylated melamine formaldehyde resin, n-butanol-etherified melamine resin, butanol-etherified urea-formaldehyde resin, isobutanol-etherified amino resin, catechol borate-etherified phenol-formaldehyde resin, dicyanophenyl-etherified phenol-biphenyl-phenol-formaldehyde resin, organic boron-modified bismaleimide resin, glycidyl-etherified bismaleimide resin, and hexamethoxymethyl melamine resin; The second multifunctional low molecular weight resin is selected from the group consisting of trimethylolpropane triacrylate, polyethylene glycol acrylate, dipropylene glycol diacrylate, trimethylolpropane trimethacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, ethoxylated glycerol triacrylate, dipentaerythritol penta / hexaacrylate, dimethylolpropionic acid diacrylate, ethoxylated trimethylolpropane triacrylate, and pentaerythritol triacrylate. The molecular weight of the second acrylate polymer is in the range of 60,000-600,000, and the second acrylate polymer contains polar groups, which include one or more combinations of hydroxyl, carboxyl, methylol, cyano, amino, amide, nitro, aldehyde, ketone, ester, and sulfonic acid groups.

6. The phase difference film according to claim 2, wherein The catalyst is selected from a combination of one or more of p-toluenesulfonic acid, zinc chloride, pyridinium p-toluenesulfonic acid, sulfuric acid, phosphotungstic acid, cesium phosphotungstic acid, silicotungstic acid, zirconium oxide sulfate, tetraisopropoxytitanium, and dodecylbenzenesulfonic acid; and / or The first solvent and the second solvent are each independently selected from one or more combinations of acetone, butanone, methyl ethyl ketone, cyclohexanone, cyclopentanone, methyl isobutyl ketone, isophorone, N-methylpyrrolidone, dioxane, tetrahydrofuran, ethyl ether, anisole, diethyl ether, propylene glycol methyl ether, n-hexane, heptane, cyclohexane, cyclopentane, toluene, xylene, dichloromethane, dichloroethane, dichlorobenzene, chlorotoluene, ethyl acetate, butyl acetate, propylene glycol methyl ether acetate, water, ethanol, n-butanol, sec-butanol, isopropyl alcohol, cyclohexanol, dimethyl sulfoxide, diethyl sulfoxide, benzylphenyl sulfoxide, dimethylformamide, dimethylacetamide, etc.; and / or The second silane coupling agent is selected from the group consisting of one or more combinations of γ-aminopropyltriethoxysilane, N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, γ-glycidyloxypropyltrimethoxysilane, γ-glycidyloxypropylmethyldiethoxysilane, vinyltriethoxysilane, γ-isocyanatepropyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-aminopropyltriethoxysilane, and trimethoxysilane; and / or The leveling agent is selected from one or more combinations of acrylics, silicones and fluorides.

7. A method for preparing a phase difference film, characterized in that: include: providing a substrate; applying the first composition according to any one of claims 1 to 6 on the substrate to form a photo-alignment layer; The second composition according to any one of claims 1 to 6 is coated on the photo-alignment layer to form a liquid crystal layer.

8. The preparation method according to claim 7, characterized in that The step of coating the first composition on the substrate to form a photo-alignment layer further comprises: a1) after coating the first composition on the substrate, heating and drying the film, wherein the heating and drying temperature is 30-250° C. and the heating time is 0.5-10 minutes; a2) curing the dried film with ultraviolet light in an N2 atmosphere to obtain the photo-alignment layer, wherein the concentration of N2 is 30%-99.999% and the irradiation energy of the ultraviolet light is 10 mJ / cm 2 -1000mJ / cm 2 and / or The step of coating the second composition on the photo-alignment layer to form a liquid crystal layer further comprises: b1) after coating the second composition on the photo-alignment layer, heating and drying the film, wherein the temperature of the heating and drying treatment is 30-250° C. and the heating time is 0.5-10 minutes; b2) curing the dried film with ultraviolet light in an N2 atmosphere to obtain the liquid crystal layer, wherein the concentration of N2 is 30%-99.999% and the irradiation energy of the ultraviolet light is 10 mJ / cm 2 -1000mJ / cm 2 .

9. The preparation method according to claim 7, characterized in that The liquid crystal molecules in the liquid crystal layer are vertically aligned.

10. The preparation method according to claim 7, characterized in that The peeling force between the photo-alignment layer and the liquid crystal layer, and between the photo-alignment layer and the substrate can be controlled. During peeling, a 3M tape or adhesive Tac is attached to the liquid crystal layer. The 3M tape or adhesive Tac is peeled off. Depending on the material adhered to the 3M tape or adhesive Tac, the following five peeling conditions can be achieved: 1) The peeling force between the photo-alignment layer and the liquid crystal layer is greater than the peeling force between the substrate and the photo-alignment layer, and the photo-alignment layer and the liquid crystal layer cannot be peeled off using 3M tape or adhesive Tac; 2) The peeling force between the photo-alignment layer and the liquid crystal layer is greater than the peeling force between the substrate and the photo-alignment layer, and the photo-alignment layer and the liquid crystal layer can be peeled off using 3M tape or adhesive Tac; 3) The peeling force between substrate and photo-alignment layer is greater than the peeling force between photo-alignment layer and liquid crystal layer, and the substrate and photo-alignment layer cannot be peeled off using 3M tape or adhesive Tac; 4) Peeling force between substrate and photo-alignment layer > peeling force between photo-alignment layer and liquid crystal layer. The substrate and photo-alignment layer can be peeled off with 3M tape or Tac tape. 5) The adhesion between the substrate, photo-alignment layer, and liquid crystal layer is greater than the adhesion between the 3M tape and the liquid crystal layer, and the substrate, photo-alignment layer, and liquid crystal layer cannot be peeled off using 3M tape or adhesive Tac.

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