Resin composition, base material, polaroid and display device

Abstract

The invention discloses a resin composition, a base material, a polaroid and a display device. The resin composition comprises cellulose ester resin, a hydrophobic modifier, a solvent, a plasticizer and an antioxidant, wherein the hydrophobic modifier is selected from any one or a combination of more of a siloxane compound, a fluorine-containing alcohol compound and a polyacrylate compound. In the application, the base material prepared from the resin composition has relatively low water vapor permeability, and the water resistance of the polaroid applying the base material can be improved, so that the problem of light leakage at four corners of the display device can be improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of display, in particular to a resin composition, a substrate, a polarizing plate and a display device. BACKGROUND

[0002] Generally, a display device includes a display panel and a polarizing plate (POL) attached to the light exit side of the display panel. Under high temperature and high humidity conditions, the polarizing plate will absorb moisture and warp, causing light leakage at the four corners of the display device, thereby affecting the display quality.

[0003] Therefore, it is necessary to improve the water resistance of the polarizing plate to improve the light leakage problem at the four corners of the display device. SUMMARY

[0004] The present application provides a resin composition, a substrate, a polarizing plate and a display device, the substrate made of the resin composition has a low water vapor transmission rate, which can improve the water resistance of the polarizing plate using the substrate, thereby helping to improve the light leakage problem at the four corners of the display device.

[0005] In order to achieve the above-mentioned purpose, according to the first aspect of the present application, a resin composition is provided, comprising cellulose ester resin, hydrophobic modifier, solvent, plasticizer and antioxidant;

[0006] The hydrophobic modifier is selected from any one or a combination of more than one of siloxane compounds, fluorine-containing alcohol compounds and polyacrylate compounds.

[0007] Optionally, the cellulose ester resin comprises triacetate cellulose ester.

[0008] Optionally, the hydrophobic modifier is selected from any one or a combination of more than one of the siloxane compounds and the fluorine-containing alcohol compounds; in the resin composition, the mass fraction of the hydrophobic modifier ranges from 1% to 15%.

[0009] Optionally, the solvent includes a main solvent and a cosolvent, and the resin composition includes the following ingredients by weight:

[0010] The cellulose ester resin: 7-13 parts;

[0011] The hydrophobic modifier: 0.2-2 parts;

[0012] The main solvent: 40-55 parts;

[0013] The cosolvent: 3.5-5 parts;

[0014] The plasticizer: 0.05-0.5 parts;

[0015] the antioxidant: 0.02 parts to 0.09 parts.

[0016] Optionally, the hydrophobic modifier is selected from any one or a combination of the polyacrylate compounds; in the resin composition, the mass fraction of the hydrophobic modifier ranges from 25% to 75%, and the mass fraction of the cellulose ester resin ranges from 25% to 75%.

[0017] Optionally, the solvent includes a main solvent and a co-solvent, and the resin composition includes the following ingredients by weight:

[0018] the cellulose ester resin: 7 parts to 13 parts;

[0019] the hydrophobic modifier: 10 parts to 20 parts;

[0020] the main solvent: 60 parts to 100 parts;

[0021] the co-solvent: 5 parts to 9 parts;

[0022] the plasticizer: 0.1 part to 1.2 parts;

[0023] the antioxidant: 0.03 parts to 0.4 parts.

[0024] Optionally, the fluorine-containing alcohol compound is selected from perfluorooctanol, and / or, the siloxane compound is selected from polysiloxane shown in Formula I, and / or, the polyacrylate compound is selected from polyacrylate shown in Formula II:

[0025]

[0026] wherein, R1 and R2 are independently selected from alkyl groups with carbon atom number ranging from 1 to 6;

[0027] n1 is selected from any one integer ranging from 15 to 50;

[0028] R3 is selected from hydrogen atom or alkyl groups with carbon atom number ranging from 1 to 8;

[0029] R4 is selected from alkyl groups with carbon atom number ranging from 1 to 8;

[0030] n2 is selected from any one integer ranging from 6 to 18.

[0031] According to the second aspect of the present application, a substrate is provided, which is prepared by using the resin composition described above, and the water vapor permeability of the substrate is less than 500 g / (m 2 ·d.

[0032] According to a third aspect of the present application, a polarizing sheet is provided, which includes at least one of the above-mentioned substrates and a polarizing functional layer provided on one side of the substrate.

[0033] According to a fourth aspect of the present application, a display device is provided, which includes a display panel and the above-mentioned polarizing sheet provided on at least one side of the display panel.

[0034] In the resin composition, the substrate, the polarizing sheet and the display device provided by the present application, by adding a hydrophobic modifier in the resin composition containing the cellulose ester resin, and the hydrophobic modifier is selected from any one or a combination of more than one of a siloxane compound, a fluorine-containing alcohol compound and a polyacrylate compound, the substrate made of the resin composition can have hydrophobicity, thereby having a lower water vapor transmission rate, and the water resistance of the polarizing sheet using the substrate can be improved, thereby being beneficial to improving the four-corner light leakage problem of the display device. BRIEF DESCRIPTION OF DRAWINGS

[0035] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative effort on the basis of these drawings.

[0036] Figure 1 is a structural schematic diagram of the substrate provided by the embodiments of the present application;

[0037] Figure 2 is a structural schematic diagram of the polarizing sheet provided by the embodiments of the present application;

[0038] Figure 3 is another structural schematic diagram of the polarizing sheet provided by the embodiments of the present application;

[0039] Figure 4 is a structural schematic diagram of the display device provided by the embodiments of the present application.

[0040] BRIEF DESCRIPTION OF DRAWINGS

[0041] 1, substrate; 2, polarizing sheet; 3, polarizing functional layer; 4, polarizing layer; 5, optical compensation layer; 6, pressure-sensitive adhesive layer; 7, release layer; 8, optical functional layer; 9, protective layer; 10, display device; 11, display panel. DETAILED DESCRIPTION

[0042] With reference to the drawings of the embodiments of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of the present application.

[0043] The applicant has found that the base material in the commonly used polarizing sheet (POL) is triacetyl cellulose (TAC), however, the water vapor transmission rate (moisture permeability) of TAC is as high as 600g / (m 2 ·d) - 700g / (m 2 ·d), under high temperature and high humidity conditions, water vapor is easy to penetrate into the PVA layer (polarizing layer) in the POL through TAC, causing the PVA molecules to move faster and move along the direction of the extension lines, resulting in shrinkage in the extension direction, and finally driving the display panel to warp, thereby causing the four corners of the display device to leak light.

[0044] To solve the above problems, the material of the base material is improved in the present application, specifically, the hydrophobic agent is used to modify the hydrophobicity of the base material, which can significantly improve the hydrophobicity of the base material and reduce the moisture permeability of the base material, thereby improving the water resistance of the polarizing sheet using the base material, and further improving the problem of four corner light leakage of the display device. For details, refer to the description of the following embodiments.

[0045] The resin composition provided by the embodiments of the present application comprises a cellulose ester resin, a hydrophobic modifier, a solvent, a plasticizer and an antioxidant. The hydrophobic modifier is selected from any one or a combination of siloxane compounds, fluorine-containing alcohol compounds and polyacrylate compounds.

[0046] In some embodiments, the resin composition consists of a cellulose ester resin, a hydrophobic modifier, a solvent, a plasticizer and an antioxidant, but is not limited thereto.

[0047] The hydrophobic modifier selected by the embodiments of the present application is any one or a combination of siloxane compounds, fluorine-containing alcohol compounds and polyacrylate compounds. The hydrophobic groups in these hydrophobic modifiers have strong interaction with the molecular backbone of the cellulose ester resin, ensuring that the hydrophobic groups in the base material prepared using the resin composition have good dispersity, thereby ensuring that the prepared base material has good hydrophobicity, and at the same time, the prepared base material also has good optical transparency and flexibility.

[0048] In the embodiments of the present application, by adding a hydrophobic modifier in the resin composition containing the cellulose ester resin, and the hydrophobic modifier is selected from any one or a combination of more than one of a siloxane compound, a fluorine-containing alcohol compound and a polyacrylate compound, the base material made of the resin composition can have hydrophobicity, thereby having a lower water vapor transmission rate, and the water resistance of the polarizing sheet using the base material can be improved, thereby being beneficial to improve the four-corner light leakage problem of the display device. Therefore, the base material with hydrophobicity can be prepared in the embodiments of the present application, thereby improving the water resistance of the polarizing sheet using the base material, and further being beneficial to improve the four-corner light leakage problem of the display device.

[0049] In some embodiments, the cellulose ester resin includes triacetate cellulose (TAC), but is not limited thereto.

[0050] In some embodiments, the siloxane compound is selected from polysiloxane shown in Formula I, and / or the polyacrylate compound is selected from polyacrylate shown in Formula II:

[0051]

[0052] wherein R1 and R2 are independently selected from alkyl groups with carbon atom number of 1 to 6;

[0053] n1 is selected from any one integer from 15 to 50;

[0054] R3 is selected from a hydrogen atom or an alkyl group with carbon atom number of 1 to 8;

[0055] R4 is selected from an alkyl group with carbon atom number of 1 to 8;

[0056] n2 is selected from any one integer from 6 to 18.

[0057] In a specific embodiment, the siloxane compound is selected from dimethyl polysiloxane, that is, R1 and R2 in the polysiloxane shown in Formula I are selected from methyl, but is not limited thereto.

[0058] In a specific embodiment, the polyacrylate compound is selected from polymethyl methacrylate, that is, R3 and R4 in the polyacrylate shown in Formula II are selected from methyl, but is not limited thereto.

[0059] In some embodiments, the fluorine-containing alcohol compound is selected from perfluorooctanol, but is not limited thereto. The chemical formula of perfluorooctanol is C6F 13 CH2CH2OH, and the chemical structure formula is shown as follows:

[0060]

[0061] It is to be noted that the above listed dimethylpolysiloxane, polymethyl methacrylate and perfluorooctanol are only described as an example, and the hydrophobic modifier of the present application is not limited to the three.

[0062] In some embodiments, the solvent includes a main solvent and a co-solvent; the main solvent is selected from one or more of dichloromethane, trichloromethane and acetone, but is not limited thereto; the co-solvent is selected from one or more of methanol, ethanol, isopropanol and ethyl acetate, but is not limited thereto.

[0063] In some embodiments, the plasticizer is selected from dipropylene glycol dibenzoate (molecular weight of 342), but is not limited thereto.

[0064] In some embodiments, the antioxidant is selected from N,N'-bis-(beta-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexylenediamine (i.e. antioxidant 1098), but is not limited thereto.

[0065] In some embodiments, the hydrophobic modifier is selected from a combination of any one or more of the siloxane compound and the fluoroalcohol compound; the mass fraction of the hydrophobic modifier in the resin composition ranges from 1% to 15%.

[0066] For example, when the hydrophobic modifier is selected from a combination of any one or more of the siloxane compound and the fluoroalcohol compound, the mass fraction of the hydrophobic modifier in the resin composition is 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%, 13.5%, 14%, 14.5% or 15%.

[0067] In some embodiments, the hydrophobic modifier is selected from a combination of any one or more of the siloxane compound and the fluoroalcohol compound, the solvent includes a main solvent and a co-solvent, and the resin composition includes the following ingredients by weight:

[0068] The cellulose ester resin: 7 parts - 13 parts;

[0069] The hydrophobic modifier: 0.2 parts - 2 parts;

[0070] The main solvent: 40 parts - 55 parts;

[0071] The co-solvent: 3.5 parts - 5 parts;

[0072] The plasticizer: 0.05 parts - 0.5 parts;

[0073] the antioxidant: 0.02 parts to 0.09 parts.

[0074] Specifically, the components in the resin composition can be mixed in a certain proportion, and then a modified substrate (e.g., a modified TAC film) can be prepared by solution casting or surface coating. Then, the modified substrate can be subjected to heat treatment to promote the interaction between the hydrophobic modifier and the molecular chain of the cellulose ester resin. The water vapor transmission rate (moisture permeability) of the substrate obtained by this method can be reduced to 350 g / (m 2 d, while the optical transparency and flexibility of the modified substrate can be maintained.

[0075] Specifically, when the hydrophobic modifier is perfluorooctanol or a siloxane compound, the long-chain structure of the perfluorooctanol or the siloxane compound can be grafted onto the molecular chain of the cellulose ester resin by graft copolymerization, which can increase the van der Waals force between molecules, thereby improving the mechanical strength of the substrate prepared using the resin composition. When the hydrophobic modifier is perfluorooctanol, the presence of fluorine atoms on the perfluorooctanol can improve the chemical stability of the film layer. Therefore, the substrate prepared using the resin composition has good hydrophobic properties, good mechanical strength, and good chemical stability, which is beneficial to improving the service life of the substrate.

[0076] It should be noted that when the hydrophobic modifier is perfluorooctanol or a siloxane compound, the long-chain structure of the perfluorooctanol or the siloxane compound is grafted onto the molecular chain of the cellulose ester resin by graft copolymerization, so that the molecular chain of the cellulose ester resin is grafted with ordered hydrophobic structures, thereby making the substrate prepared using the resin composition have good hydrophobic properties.

[0077] When the cellulose ester resin is triacetate cellulose (TAC), the acetyl group on the molecular chain of TAC undergoes graft copolymerization with the hydrophobic modifier, thereby grafting the hydrophobic modifier onto the molecular chain of TAC, so that the prepared TAC substrate has good hydrophobic properties.

[0078] In other embodiments, the hydrophobic modifier is selected from any one or a combination of the polyacrylate compounds; in the resin composition, the mass fraction of the hydrophobic modifier ranges from 25% to 75%, and the mass fraction of the cellulose ester resin ranges from 25% to 75%.

[0079] For example, when the hydrophobic modifier is selected from a combination of one or more of the polyacrylate compounds, the mass fraction of the hydrophobic modifier in the resin composition is 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, or 75%, and the mass fraction of the cellulose ester resin is 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, or 75%.

[0080] In some embodiments, when the hydrophobic modifier is selected from a combination of one or more of the polyacrylate compounds, the ratio of the mass fraction of the hydrophobic modifier to the mass fraction of the cellulose ester resin in the resin composition ranges from (1-1.5): 1, but is not limited thereto.

[0081] Applicants have found that, when the hydrophobic modifier is selected from a combination of one or more of the polyacrylate compounds, the moisture permeability of the prepared substrate decreases as the ratio of the mass fraction of the hydrophobic modifier to the mass fraction of the cellulose ester resin in the resin composition increases. Therefore, increasing the proportion of the polyacrylate compound is beneficial to improving the hydrophobicity of the prepared substrate.

[0082] In some embodiments, when the hydrophobic modifier is selected from a combination of one or more of the polyacrylate compounds, the resin composition comprises the following ingredients by weight:

[0083] The cellulose ester resin: 7-13 parts;

[0084] The hydrophobic modifier: 10-20 parts;

[0085] The main solvent: 60-100 parts;

[0086] The co-solvent: 5-9 parts;

[0087] The plasticizer: 0.1-1.2 parts;

[0088] The antioxidant: 0.03-0.4 parts.

[0089] It can be understood that, when the hydrophobic modifier is selected from a combination of one or more of the polyacrylate compounds, the weight ratio of each component in the resin composition needs to be adjusted, and the selection of the other components except the hydrophobic modifier does not need to be adjusted.

[0090] Specifically, the polyacrylate compound is a macromonomer with a hydrophobic comb structure, which can undergo random copolymerization with the cellulose ester resin, thereby forming a randomly arranged hydrophobic comb structure on the molecular chain of the cellulose ester resin, so that the substrate prepared by using the resin composition has good hydrophobic property.

[0091] It should be noted that random arrangement means that the hydrophobic comb structure is randomly connected to the molecular chain of the cellulose ester resin without fixed arrangement order.

[0092] When the cellulose ester resin is triacetate cellulose (TAC), the acetyl group on the molecular chain of TAC undergoes random copolymerization with the hydrophobic modifier, thereby randomly connecting the hydrophobic comb structure as a side chain to the molecular chain of TAC, so that the prepared TAC substrate has good hydrophobic property.

[0093] As shown in Figure 1 The embodiment of the present application also provides a substrate 1 prepared by using the resin composition of the foregoing embodiment.

[0094] In some embodiments, the water vapor transmission rate (moisture permeability) of the substrate 1 is less than 500 g / (m 2 ·d).

[0095] In some embodiments, the water vapor transmission rate of the polarizing sheet of the substrate 1 is as low as 350 g / (m 2 ·d).

[0096] In some embodiments, the substrate 1 is a hydrophobically modified TAC film, that is, the cellulose ester resin in the resin composition is triacetate cellulose (TAC).

[0097] In some embodiments, the method for manufacturing the substrate 1 comprises the following steps:

[0098] The main solvent, the cosolvent, the plasticizer, the hydrophobic modifier, and the antioxidant are mixed in a predetermined proportion and stirred to obtain a mixed liquid;

[0099] The cellulose ester resin (for example, triacetate cellulose) is added to the foregoing mixed liquid, and the mixture is stirred to obtain a size liquid;

[0100] The foregoing size liquid is filtered several times and then left to stand for defoaming, and then the size liquid is cast to form a wet film with uniform thickness; and

[0101] The foregoing wet film is dried by a drying box, and then wound to obtain a substrate (for example, a modified triacetate cellulose film) with a predetermined thickness.

[0102] It can be understood that the stirring time, the number of filtration and the temperature during the drying process in the above preparation method can be adjusted according to the actual situation, and the present application embodiment does not limit this.

[0103] In some embodiments, when preparing the mixed liquid, heating can also be appropriately performed to accelerate the dissolution of each component, thereby shortening the mixing time.

[0104] In the present application embodiment, the preparation of the aforementioned wet film from the aforementioned resin composition can be carried out at room temperature, and the preparation method is simple and easy to implement, which is conducive to reducing the manufacturing cost of the substrate 1.

[0105] In a specific embodiment, when the cellulose ester resin is selected from triacetate cellulose (TAC), and the hydrophobic modifier is selected from dimethyl polysiloxane or perfluorooctanol, the preparation process of the substrate 1 is as follows: the main solvent, the cosolvent, the plasticizer, the hydrophobic modifier and the antioxidant are mixed and stirred for 120 minutes (min) to obtain a mixed liquid; then the triacetate cellulose is added to the mixed liquid and stirred for 200 min to obtain a size liquid, the size liquid is finely filtered twice, and is left to stand for 6.5 hours (h) to remove bubbles; then the size liquid is cast to form a wet film with uniform thickness; and the wet film is dried by a drying box and then wound to obtain a modified triacetate cellulose film (i.e. the substrate) with a thickness of 40 um.

[0106] In another specific embodiment, when the cellulose ester resin is selected from triacetate cellulose (TAC), and the hydrophobic modifier is selected from polymethyl methacrylate, the preparation process of the substrate 1 is as follows: the main solvent, the cosolvent, the plasticizer, the polymethyl methacrylate and the antioxidant are mixed and stirred for 120 min to obtain a mixed liquid; then the triacetate cellulose is added to the mixed liquid and stirred for 230 min to obtain a size liquid; the size liquid is finely filtered twice, and is left to stand for 7.5 h to remove bubbles; then the size liquid is cast to form a wet film with uniform thickness; and the wet film is dried by a drying box and then wound to obtain a modified triacetate cellulose film (i.e. the substrate) with a thickness of 40 um.

[0107] In the present application embodiment, the substrate 1 prepared from the aforementioned resin composition has good hydrophobic properties, and the hydrophobic groups have strong interaction with the molecular main chain of the cellulose ester resin, which ensures good dispersibility of the hydrophobic groups in the substrate 1, and the strong interaction between the hydrophobic groups in the substrate 1 forms a non-covalent bond network structure, which is conducive to enhancing the stability of the substrate, thereby avoiding the warping of the optical film (e.g. polarizing film) applied with the substrate 1 under high temperature and high humidity conditions due to the influence of water vapor, and effectively improving or avoiding the problem of four-corner light leakage of the display device applied with the optical film.

[0108] For example, the display device can be a liquid crystal display device, an organic light-emitting diode display device, or a micro-LED display device. Figure 2 For example, the display device can be a liquid crystal display device, an organic light-emitting diode display device, or a micro-LED display device. Figure 3As shown, this application embodiment also provides a polarizer 2, which includes at least one substrate 1 as described above and a polarizing functional layer 3 disposed on one side of the substrate 1.

[0109] In some embodiments, the polarizing functional layer 3 includes a polarizing layer 4, the material of which includes, but is not limited to, polyvinyl alcohol (PVA).

[0110] Understandably, polarizing layer 4 plays a polarizing role and is the core structure of polarizer 2.

[0111] In some embodiments, the water vapor transmittance of the polarizer 2 is less than 500 g / (m²). 2 ·d).

[0112] In some embodiments, the water vapor transmittance of the polarizer 2 is as low as 350 g / (m²). 2 ·d).

[0113] In some embodiments, the polarizing functional layer 3 further includes an optical compensation layer 5, and the optical compensation layer 5 is disposed on the side of the polarizing layer 4 facing away from the substrate 1. The optical compensation layer 5 includes, but is not limited to, a phase compensation layer, a filter layer, a phase difference film, or a light deflection film.

[0114] In some embodiments, the polarizer 2 further includes a pressure-sensitive adhesive layer 6 and a release film 7 disposed on the side of the polarizing functional layer 3 opposite to the substrate 1, wherein the release film 7 is located on the side of the pressure-sensitive adhesive layer 6 opposite to the polarizing functional layer 3. It is understood that the release film 7 is removed during use, allowing the polarizer 2 to be fixed to a structure such as a display panel via the pressure-sensitive adhesive layer 6.

[0115] In some embodiments, the polarizer 2 further includes a protective layer 9 disposed on the side of the substrate 1 opposite to the polarizing functional layer 3. It is understood that the protective layer 9 may be removed when the polarizer 2 is in use.

[0116] In some embodiments, such as Figure 3 As shown, the polarizer 2 also includes an optical functional layer 8 disposed on the side of the substrate 1 opposite to the polarizing functional layer 3. The optical functional layer 8 includes, but is not limited to, surface coatings such as an anti-reflection layer, an anti-glare layer, and a hardening layer. At this time, the protective layer 9 is located on the side of the optical functional layer 8 opposite to the substrate 1.

[0117] In some embodiments, the polarizer 2 may have two substrates 1, and the two substrates 1 are connected by an adhesive layer.

[0118] This application also uses three substrates prepared from the three resin compositions provided in the embodiments of this application, and tests the moisture transmittance and light transmittance of these three substrates when applied to polarizers, as described below.

[0119] Example 1

[0120] (1) Preparation of the first modified TAC substrate:

[0121] 50 parts by weight of dichloromethane (main solvent), 4 parts by weight of ethanol (co-solvent), 0.26 parts by weight of dipropylene glycol dibenzoate (plasticizer), 1.0 parts by weight of perfluorooctanol, and 0.06 parts by weight of antioxidant 1098 were mixed and stirred for 120 min to obtain a mixed liquid; 9.7 parts by weight of cellulose triacetate was then added to the mixed liquid and stirred for 200 min to obtain a size liquid. The size liquid was finely filtered twice, allowed to stand for 6.5 h to remove bubbles, and then cast to form a wet film with uniform thickness. After drying in a drying oven, the film was wound up to obtain a first modified TAC substrate with a thickness of 40 um.

[0122] (2) Preparation of the first polarizing sheet:

[0123] The first modified TAC substrate prepared in step (1) was subjected to alkalization to improve the hydrophilicity of the first modified TAC substrate, and then was three-layer-composited with a PVA film and a compensation film layer (VA display mode) or a zero compensation film layer (IPS / FFS display mode) after water washing, swelling, dyeing, stretching, color fixing, and drying processes to obtain a polarizing sheet substrate. Pressure-sensitive adhesive was coated on a PET film with a release agent, and then was bonded to the polarizing sheet substrate after heating at 105°C for 3 min to form the first polarizing sheet.

[0124] Example 2

[0125] (1) Preparation of the second modified TAC substrate:

[0126] The preparation method of the second modified TAC substrate was the same as that of the first modified TAC substrate, except that the formulation of the resin composition in Example 2 was 9.7 parts by weight of cellulose triacetate, 0.9 parts by weight of dimethylpolysiloxane (hydrophobic modifier), 50 parts by weight of dichloromethane (main solvent), 4 parts by weight of ethanol (co-solvent), 0.24 parts by weight of dipropylene glycol dibenzoate (plasticizer), and 0.06 parts by weight of antioxidant 1098.

[0127] (2) Preparation of the second polarizing sheet:

[0128] The preparation method of the second polarizing sheet was the same as that of the first polarizing sheet, and will not be described here.

[0129] Example 3

[0130] (1) Preparation of the third modified TAC substrate:

[0131] 80 parts by weight of dichloromethane (main solvent), 7 parts by weight of ethanol (co-solvent), 0.5 parts by weight of diphenyl acid dimeric propylene glycol ester (plasticizer), 15 parts by weight of polymethyl methacrylate (molecular weight 800-2000), 0.1 parts by weight of antioxidant 1098 are mixed and stirred for 120 min to obtain a mixed liquid, then 10 parts by weight of cellulose triacetate is added to the mixed liquid and stirred for 230 min to obtain a size liquid, the size liquid is fine filtered twice, and then deaerated for 7.5 h, and then the size liquid is cast to form a wet film with uniform thickness, dried through a drying box, and then wound to obtain a third modified TAC substrate with a thickness of 40 um.

[0132] (2) Preparation of the third polarizing sheet:

[0133] The preparation method of the third polarizing sheet is the same as that of the first polarizing sheet, which will not be repeated here.

[0134] Comparative example

[0135] The preparation method of the comparative TAC substrate and the preparation method of the comparative polarizing sheet using the comparative TAC substrate are the same as those of the first modified TAC substrate, the second modified TAC substrate, or the third modified TAC substrate, and the preparation method of the comparative polarizing sheet and the preparation method of the first polarizing sheet are the same. Different from the first to third examples is that no hydrophobic modifier is added in the preparation process of the comparative TAC substrate.

[0136] The comparative polarizing sheet, the first polarizing sheet, the second polarizing sheet, and the third polarizing sheet prepared in the comparative example, the first example, the second example, and the third example, respectively, are subjected to moisture permeability test and light transmittance test, and the results are shown in Table 1.

[0137] The moisture permeability test method is as follows: using a moisture permeability cup, 30g±0.2g of desiccant is placed in the moisture permeability cup, the sample (e.g. the comparative polarizing sheet, the first polarizing sheet, the second polarizing sheet, and the third polarizing sheet) is fixed to the moisture permeability cup with the black fixture facing outward, and then locked, placed in a constant temperature and humidity machine (temperature: 38℃; humidity: 90%RH; air flow speed: 0.3-0.5m / s) for 24 hours, and then immediately weighed after taking out, and the data is recorded. The data is substituted into the moisture permeability calculation formula to calculate the moisture permeability data of each polarizing sheet sample. The unit of moisture permeability in Table 1 is g / (m 2 ·d).

[0138] The moisture permeability calculation formula is: (mt-m0) / π*r 2 ;

[0139] Wherein, mt represents the weight after placing in the constant temperature and humidity machine, m0 represents the weight before placing in the constant temperature and humidity machine, and r represents the radius of the circular polarizing sheet sample.

[0140] It should be noted that in the moisture permeability test, the sample is often cut into a circular shape to facilitate fixation in the test fixture and avoid edge sealing problems.

[0141] Specifically, the light transmittance in Table 1 is tested by a v7100 type ultraviolet spectrophotometer.

[0142] Table 1

[0143] Comparative Example Example 1 Example 2 Example 3 Moisture permeability 700 350 355 471 Light transmission / % 92.1 92.2 92.0 92.1 Thickness / um 40 40 40 40

[0144] As can be seen from Table 1, the moisture permeability of the first polarizing sheet, the second polarizing sheet and the third polarizing sheet provided by Examples 1-3 is less than 500 g / (m 2 ·d) compared with the control polarizing sheet provided by the control example, and the moisture permeability of the first polarizing sheet provided by Example 1 is as low as 350 g / (m 2 ·d), which shows that the substrate prepared from the resin composition provided by the present application can effectively reduce the moisture permeability of the polarizing sheet when applied to the polarizing sheet.

[0145] At the same time, as can be seen from Table 1, the light transmittance of the polarizing sheets provided by the control example, Examples 1-3 is greater than 90%, and the light transmittance of the control polarizing sheet, the first polarizing sheet, the second polarizing sheet and the third polarizing sheet is basically consistent, which shows that modifying the raw material of the substrate will not affect the light transmittance of the substrate.

[0146] Therefore, the hydrophobicity of the substrate prepared from the resin composition provided by the present application is significantly improved while maintaining high light transmittance.

[0147] In the present application, since the water resistance of the substrate 1 in the polarizing sheet 2 is significantly improved, the water vapor that penetrates through the substrate 1 into the polarizing layer (e.g. PVA layer) 4 during the high temperature and high humidity process can be effectively reduced, which can effectively improve the durability of the polarizing sheet 2, so that the warping caused by the shrinkage or swelling of the polarizing sheet 2 in a high temperature and high humidity environment can be effectively inhibited, thereby avoiding the bending of the display panel, and further avoiding the phenomenon of light leakage at the four corners of the display device.

[0148] The present application also provides Examples 4 to 6, which verify the influence of the ratio of the mass fraction of the hydrophobic modifier to the mass fraction of the cellulose ester resin on the moisture permeability of the prepared substrate when the cellulose ester resin is selected from cellulose triacetate and the hydrophobic modifier is selected from polymethyl methacrylate.

[0149] Example 4

[0150] Example 4 provides a fourth modified TAC substrate, the preparation process of the fourth modified TAC substrate is the same as that of the third modified TAC substrate, except that the ratio of the mass fraction of polymethyl methacrylate (PMMA, molecular weight 800-2000) to the mass fraction of triacetate cellulose (TAC) in the resin composition used for preparing the fourth modified TAC substrate is 1.5:1.

[0151] Example 5

[0152] Example 5 provides a fifth modified TAC substrate, the preparation process of the fifth modified TAC substrate is the same as that of the third modified TAC substrate, except that the ratio of the mass fraction of polymethyl methacrylate (PMMA, molecular weight 800-2000) to the mass fraction of triacetate cellulose (TAC) in the resin composition used for preparing the fifth modified TAC substrate is 1:1.

[0153] Example 6

[0154] Example 6 provides a sixth modified TAC substrate, the preparation process of the sixth modified TAC substrate is the same as that of the third modified TAC substrate, except that the ratio of the mass fraction of polymethyl methacrylate (PMMA, molecular weight 800-2000) to the mass fraction of triacetate cellulose (TAC) in the resin composition used for preparing the sixth modified TAC substrate is 1:3.

[0155] It can be understood that the difference of the corresponding resin composition of Example 4 to Example 6 is only that the weight ratio of the hydrophobic modifier PMMA to the cellulose ester resin TAC is different.

[0156] The fourth modified TAC substrate, the fifth modified TAC substrate and the sixth modified TAC substrate prepared by Example 4, Example 5 and Example 6 respectively are subjected to moisture permeability test, and the results are shown in Table 2.

[0157] Specifically, the moisture permeability test method is as described above, which is not repeated here. The unit of the moisture permeability in Table 2 is g / (m 2 ·d).

[0158] Table 2

[0159] Example 4 Example 5 Example 6 PMMA : TAC 1.5:1 1:1 1:3 Moisture permeability 359 471 604

[0160] As can be seen from Table 2, when the hydrophobic modifier is selected from PMMA, the moisture permeability of the prepared substrate is reduced as the ratio of the mass fraction of the hydrophobic modifier to the mass fraction of the cellulose ester resin in the resin composition increases. Therefore, appropriately increasing the proportion of PMMA is conducive to improving the hydrophobicity of the prepared substrate.

[0161] As shown in Figure 4 The display device 10 provided by the embodiments of the present application includes a display panel 11 and the polarizing sheet 2 provided by the above-mentioned embodiments, and the polarizing sheet 2 is arranged on at least one side of the display panel 11.

[0162] In some embodiments, the display panel 11 is a liquid crystal display panel, but is not limited thereto. In this case, the polarizing sheet 2 provided by the above-mentioned embodiments is arranged on the light-emitting side of the display panel 11.

[0163] In some embodiments, the polarizing sheet 2 provided by the above-mentioned embodiments can also be arranged on the backlight side of the display panel 11.

[0164] In the embodiments of the present application, the water resistance of the substrate in the polarizing sheet 2 is significantly improved, so that the water vapor that penetrates into the polarizing layer (for example, the PVA layer) through the substrate during the high-temperature and high-humidity process can be effectively reduced, the durability of the polarizing sheet 2 can be effectively improved, the warping caused by the shrinkage or swelling of the polarizing sheet 2 in the high-temperature and high-humidity environment can be effectively inhibited, and thus the bending of the display panel 11 can be avoided, and the phenomenon of light leakage at the four corners of the display device 10 can be avoided.

[0165] The above describes in detail the resin composition, the substrate, the polarizing sheet and the display device provided by the embodiments of the present application. The principles and implementation manners of the present application are described by using specific examples. The above-mentioned embodiments are only used to help understand the method of the present application and its core idea; meanwhile, for those skilled in the art, according to the idea of the present application, the specific implementation manners and application ranges can be changed, and the above-mentioned description should not be understood as the limitation of the present application.

Claims

1. A resin composition, characterized by, The cellulose ester resin, a hydrophobic modifier, a solvent, a plasticizer, and an antioxidant are included. The hydrophobic modifier is selected from a combination of any one or more of a siloxane compound, a fluoroalcohol compound, and a polyacrylate compound.

2. The resin composition according to claim 1, characterized by The cellulose ester resin includes triacetate cellulose.

3. The resin composition according to claim 1, characterized by The hydrophobic modifier is selected from a combination of any one or more of the siloxane compound and the fluoroalcohol compound; the mass fraction of the hydrophobic modifier in the resin composition ranges from 1% to 15%.

4. The resin composition according to claim 3, characterized by The solvent includes a main solvent and a co-solvent, and the resin composition includes the following ingredients by weight: The cellulose ester resin: 7-13 parts; The hydrophobic modifier: 0.2-2 parts; The main solvent: 40-55 parts; The co-solvent: 3.5-5 parts; The plasticizer: 0.05-0.5 parts; The antioxidant: 0.02-0.09 parts.

5. The resin composition according to claim 1, characterized by The hydrophobic modifier is selected from a combination of any one or more of the polyacrylate compound; the mass fraction of the hydrophobic modifier in the resin composition ranges from 25% to 75%, and the mass fraction of the cellulose ester resin ranges from 25% to 75%.

6. The resin composition according to claim 5, characterized by The solvent includes a main solvent and a co-solvent, and the resin composition includes the following ingredients by weight: The cellulose ester resin: 7-13 parts; The hydrophobic modifier: 10-20 parts; The main solvent: 60-100 parts; The co-solvent: 5-9 parts; The plasticizer: 0.1-1.2 parts; The antioxidant: 0.03-0.4 parts.

7. The resin composition according to any one of claims 1 to 6, characterized by The fluoroalcohol compound is selected from perfluorooctanol, and / or, the siloxane compound is selected from polysiloxane shown in Formula I, and / or, the polyacrylate compound is selected from polyacrylate shown in Formula II: R1 and R2 are independently selected from alkyl groups with 1-6 carbon atoms; n1 is selected from any one integer from 15 to 50; R3 is selected from a hydrogen atom or an alkyl group with 1-8 carbon atoms; R4 is selected from an alkyl group with 1-8 carbon atoms; n2 is selected from any one integer from 6 to 18.

8. A substrate, characterized by, The substrate is produced using the resin composition according to any one of claims 1 to 7, and the water vapor permeability of the substrate is less than 500 g / (m 2 d).

9. A polarizing sheet characterized by comprising: The polarizing functional layer is disposed on one side of the substrate.

10. A display device, characterized by comprising: The display panel and the polarizing sheet of claim 9 are included, and the polarizing sheet is disposed on at least one side of the display panel.

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