Liquid crystal composition, anisotropic body, optical film and phase difference film

Abstract

The invention provides a liquid crystal composition which comprises the following components in parts by weight: 1-50 parts of a compound as shown in a formula M-1 and 35-99 parts of a compound as shown in a formula M-2. The invention also provides an anisotropic body, an optical film and a phase difference film. According to the liquid crystal composition provided by the invention, on the premise that the wavelength dispersity (R450 / R550 value) of an optical film system is maintained, the proportion of the added n-dispersing monomer can be higher, and meanwhile, the clearing point temperature of the composition system can be higher, so that the widening of a processing technology temperature window and the reduction of the manufacturing cost are facilitated.

Description

Technical Field

[0001] The present invention relates to a liquid crystal composition, more specifically, to a liquid crystal composition for preparing an optical film material. The present invention also relates to an anisotropic body obtained by polymerizing the liquid crystal composition, an optical film and a phase difference film. Background Art

[0002] Optical film is a key component in modern display technology. It can affect the display brightness, clarity, large viewing angle color deviation and other performances that affect the display weight. Among them, the reverse wavelength dispersion phase retardation film is widely used in the polarizer of liquid crystal display (LCD) and organic light emitting diode display (OLED) for anti-reflection and viewing angle compensation due to its unique optical properties. Reverse wavelength dispersion usually refers to the phase delay amount is proportional to the wavelength at a positive viewing angle. It is usually expressed by the phase delay amount R450 at a wavelength of 450nm and the phase delay amount R550 at a wavelength of 550nm satisfying the following conditions: R450 / R550≤1.0; the reverse wavelength dispersion phase retardation film is just close to the display device's requirements for the phase delay amount of the full-band visible light wavelength. Compared with the stacked structure of multi-layer anisotropic bodies, the single-layer reverse wavelength dispersion phase retardation film can simplify the layer structure of the optical film and achieve a thinner product thickness.

[0003] The phase retardation film that achieves reverse wavelength dispersion currently mainly uses liquid crystal polymer materials. Mainstreamly, these liquid crystal polymers usually use prepolymer coating liquid as a precursor. The formula contains liquid crystal monomers with polymerizable groups, initiators, solvents, etc. In order for the liquid crystal to obtain a certain orientation, there should also be a functional alignment layer on the supporting substrate. After coating the precursor solution on the substrate containing the alignment layer, after the heating and drying steps, after the solvent evaporates, the liquid crystal compound forms a liquid crystal phase with a specific orientation (ie "alignment") under certain temperature conditions. Subsequently, the polymerization reaction is initiated by ultraviolet light to fix the alignment of the liquid crystal, thereby obtaining an anisotropic polymer film with a regular orientation, which then has the optical properties of phase delay.

[0004] In the manufacture of phase retardation films, the control of large-area uniformity of liquid crystal orientation is the key to affecting the optical quality of the film material, which requires fine-tuning of the formulation process and processing technology to achieve. As the core of these prepolymer formulations, the reverse wavelength dispersion monomer contains a relatively large conjugated group in its molecular structure, which leads to its poor solubility and alignment with liquid crystals, and the difficulty of synthesis will also increase. Therefore, compared with the general positive dispersion liquid crystal monomer, the process window of film making is narrower, the monomer is easy to crystallize or cause alignment disorder on the film material, and it is more difficult to achieve good alignment in a wider temperature range, affecting the flexibility of process adjustment. The process window of liquid crystal prepolymer generally does not exceed the clearing point (Tni) of the solid content of the formula. When the processing temperature exceeds the clearing point, the liquid crystal prepolymer will be isotropic, so that the phase difference disappears. Therefore, the clearing point of the liquid crystal prepolymer is higher, indicating a wider processing window.

[0005] In order to adjust the optical properties (such as R450 / R550) and processing properties, some positively dispersed liquid crystal prepolymer monomers are often added to the reverse dispersion composition. The addition of positively dispersed liquid crystal monomers is conducive to the coordination of the orientation and anti-crystallization of the liquid crystal system, but when too much is added, the optical performance R450 / 550 value will become larger and larger, and the anti-reflection performance will also deteriorate. From the perspective of balancing optical properties and manufacturing costs, as much positively dispersed monomers as possible should be added to the prepolymer formula (relative to most reverse dispersion monomers, the cost of positively dispersed monomers is lower), and at the same time, the R450 / R550 value does not exceed the design value of the product. Currently, the more popular positively dispersed liquid crystal monomers on the market, such as LC242, RM82, RM257, etc., are widely used in anisotropic materials. The characteristics are that they contain a liquid crystal unit structure with three benzene rings in series, and the molecular weight is relatively small (about 600). When diluted in the reverse dispersion monomer as a positively dispersed monomer, the processable temperature range of the system is often narrowed, especially the upper temperature limit, which will be greatly reduced. At the same time, the R450 / R550 value will also increase sharply, making the reverse dispersion performance worse. These factors are not conducive to improving the performance and processability of the product.

[0006] In summary, it can be seen that the existing technology has long had the problem that adding positively dispersible monomers to the formula for preparing optical films often narrows the processable temperature range of the system and deteriorates the reverse dispersion performance of the optical film. Therefore, it is necessary to propose improved technical means to solve this problem. Summary of the invention

[0007] To solve the problems existing in the prior art, the present application provides a liquid crystal composition for preparing an optical film. The liquid crystal composition can have a higher proportion of positive dispersion monomers added while maintaining the wavelength dispersion (R450 / R550 value) of the optical film system, and the clearing point (Tni) temperature of the composition system is higher. Therefore, it is beneficial to broaden the processing temperature window and reduce the manufacturing cost.

[0008] According to the first aspect of the present application, there is provided a liquid crystal composition, which comprises 1 to 50 parts by weight of a compound represented by formula M-1 and 35 to 99 parts by weight of a compound represented by formula M-2;

[0009]

[0010] wherein, in formula M-1 and formula M-2, L 1 ~L 8 each independently selected from groups;

[0011] In formula M-1, H 1 ~H 2 each independently selected from groups;

[0012] In formula M-1 and formula M-2, Z 1 ~Z 4 、H 3 ~H 4 each independently selected from

[0013] groups;

[0014] In formula M-1 and formula M-2, J 1 ~J 4 each independently selected from groups or single bonds;

[0015] In formula M-1 and formula M-2, Y 1 ~Y 4 each independently selected from alkyl chains, where n = 2 to 20 and the n values in the alkyl chains of Y 1 ~Y 4 are the same or different;

[0016] In formula M-1 and formula M-2, R 1 ~R 4 each independently selected from groups;

[0017] In formula M-1, X 1 ~X 4 They can represent hydrogen atoms, halogen atoms or the following functional groups:

[0018]

[0019] Among them, A 1 , A 2 is any saturated alkane chain having 1 to 20 carbon atoms;

[0020] B 1 Each independently selected from or, n=1-20;

[0021] R 5 Selected from Group;

[0022] In formula M-2, W 1 ~W 4 Each independently is capable of making the compound represented by formula M-2 max = Any organic group with a molecular weight of 330 nm to 420 nm.

[0023] Optionally, the compound represented by formula M-1 includes at least one of the compounds represented by the following formulae M-1-1 to M-1-14:

[0024]

[0025]

[0026] Optionally, the compound represented by formula M-2 includes at least one of the compounds represented by the following formulae M-2-1 to M-2-10:

[0027]

[0028]

[0029] Optionally, the liquid crystal composition further comprises 0.2 to 10 parts by weight of an initiator, wherein the initiator comprises at least one of the compounds represented by the following formulae I-1 to I-7:

[0030]

[0031] Optionally, the liquid crystal composition comprises, by weight, 10 to 30 parts of the compound represented by formula M-1, 65 to 90 parts of the compound represented by M-2, and 3 to 7 parts of the initiator represented by formulas I-1 to I-7.

[0032] Optionally, the liquid crystal composition further includes 0.01 to 5 parts of an auxiliary agent in parts by weight, and the auxiliary agent includes a combination of one or more of a leveling and defoaming auxiliary agent, an inhibitor, and a chain transfer agent; wherein: the leveling and defoaming auxiliary agent includes at least one of BYK-300, BYK-306, BYK-358, BYK-354, BYK-515, BYK-3560, BYK-3566, MEGAFACE F-554, F-556, Zonyl FS-520, and Zonyl 8857A; the inhibitor includes at least one of benzoquinone, hydroquinone, and 2,6-di-tert-butyl-4-methylphenol (BHT); the chain transfer agent includes at least one of dodecanethiol and triethylamine.

[0033] Optionally, the liquid crystal composition further includes 100 to 1200 parts of a solvent, measured by weight, and the solvent includes at least one of the following: toluene, xylene, chlorobenzene, ethylbenzene, butanone, 3-pentanone, cyclopentanone, cyclohexanone, N-methylpyrrolidone, isophorone, ethyl acetate, butyl acetate, propylene glycol methyl ether acetate, n-butanol, isopropanol, propylene glycol methyl ether, N,N-dimethylformamide, ethanolamine, and acetonitrile.

[0034] According to a second aspect of the present application, an anisotropic body is provided. The anisotropic body is obtained by polymerizing the liquid crystal composition described in the first aspect of the present application.

[0035] According to a third aspect of the present application, an optical film is provided, which includes a polymerization product of the liquid crystal composition described in the first aspect of the present application or includes the anisotropic body described in the second aspect of the present application.

[0036] According to the fourth aspect of the present application, a phase difference film is provided, which includes a polymerization product of the liquid crystal composition described in the first aspect of the present application or includes the anisotropic body described in the second aspect of the present application, wherein the phase retardation R450 of the phase difference film at a wavelength of 450nm and the phase retardation R550 at a wavelength of 550nm satisfy the following condition: R450 / R550≤1.0.

[0037] The technical solution adopted by the present invention can achieve the following beneficial effects:

[0038] The liquid crystal composition provided by the present invention can have a higher proportion of positive dispersion monomers added while maintaining the wavelength dispersion (R450 / R550 value) of the optical film system, and the clearing point (Tni) temperature of the composition system can be higher, which is conducive to widening the processing temperature window and reducing the manufacturing cost. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the specific embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0040] The technical solutions disclosed in various embodiments of the present invention are described in detail below.

[0041] The present application discloses a liquid crystal composition, which comprises, by weight, at least one compound represented by formula M-1 and at least one compound represented by formula M-2, wherein the compound represented by formula M-1 is a positively dispersible polymerizable monomer, and the compound represented by formula M-2 is a reversely dispersible polymerizable monomer, and the M-1 monomer has a structure similar to that of the M-2 monomer, and is composed of five six-membered rings on the liquid crystal unit, and at least two of the five six-membered rings are cyclohexane-type six-membered rings. Therefore, this composition can improve the optical properties (reduce the increase in R450 / R550) while broadening the upper and lower limits of the processing temperature of the system. Wherein, formula M-1 and formula M-2 are respectively as follows:

[0042]

[0043] Wherein, in Formula M-1 and Formula M-2, L 1 ~L 8 Each independently selected from Group; in formula M-1, H 1 ~H 2 Each independently selected from Group; In formula M-1 and formula M-2, Z 1 ~Z 4 , H 3 ~H 4 Each independently selected from Group; In formula M-1 and formula M-2, J 1 ~J 4 Each independently selected from group or a single bond; in formula M-1 and formula M-2, Y 1 ~Y 4 Each independently selected from an alkyl chain, wherein n=2 to 20 and Y 1 ~Y 4 The values ​​of n in the alkyl chain can be the same or different. 1 , Y 2 , Y 3、 Y4 The alkyl chain length can be different; in M-1 and M-2, R 1 ~R 4 Each independently selected from Group; In formula M-1, X 1 ~X 4 They can represent hydrogen atoms, halogen atoms or the following functional groups: Among them, A 1 , A 2 is any saturated alkane chain with 1 to 20 carbon atoms; 1 Each independently selected from or, n = 1-20; R 5 Selected from Group; In formula M-2, W 1 ~W 4 Each independently is capable of making the compound represented by formula M-2 max = Any organic group with a molecular weight of 330 nm to 420 nm.

[0044] In a preferred embodiment, from the perspective of the difficulty of raw material synthesis and the solubility of the monomer, L 1 ~L 4 Preferred Group. H 1 ~H 2 Preferred use Group; Z 1 ~Z 2 Preferred use Group.

[0045] Among them, X 1 ~X 4 It is a side group of the liquid crystal molecule, which mainly plays the role of increasing the reactive functional group, changing the liquid crystal phase temperature of the molecule, increasing the solubility, etc. Therefore, it is preferred to use a single substitution (i.e., X 1 ~X 4 is a substituent other than hydrogen, and the other three are selected from hydrogen) or disubstituted (i.e., X 1 ~X 4 Two of them are substituents other than hydrogen, and the other two are selected from hydrogen), more preferably monosubstituted. 1 ~X 4 The functional groups to be substituted are preferably the following:

[0046] Among them, A 1 , A 2 The alkane chain length is preferably 3 to 10.

[0047] Among them, R1 ~R 5 is a reactive group, which enables the liquid crystal molecules (i.e., the molecules of formula M-1 or formula M-2) to initiate polymerization under light or heat conditions to form a cross-linked network. Therefore, these groups are one of the essential elements of the present invention. From the perspective of wide application, R 1 ~R 5 The following groups are preferred:

[0048]

[0049] In the above-mentioned liquid crystal composition, M-1 may contain only one compound, but may also be a combination of multiple compounds conforming to the general formula of M-1. In the liquid crystal composition of the present invention, the recommended total amount of M-1 monomers is 1 to 50 parts by weight, preferably 10 to 30 parts, and more preferably 20 to 25 parts. For example, in the liquid crystal composition provided by the present invention, the weight parts of the compound represented by formula M-1 may be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 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, 46, 47, 48, 49, 50 parts or any value between these numbers.

[0050] As a specific embodiment, the compound represented by formula M-1 may include, but is not limited to, at least one of the compounds represented by the following formulae M-1-1 to M-1-14:

[0051]

[0052]

[0053] The compound represented by the above formula M-2 belongs to a polymerizable monomer with reverse wavelength dispersion. The key to the formation of reverse wavelength dispersion is that the optical density of the side groups is relatively large, so that the side groups have a relatively large refractive index in the vertical direction of the long axis of the liquid crystal molecules, that is, in the short axis direction, thereby causing a relatively large refractive index difference between the blue light and the red light wavelength. In the present invention, we 1 ~W 4), but does not make specific requirements for the specific functional groups of M-2, but stipulates the maximum absorption wavelength of the M-2 molecule, that is, λmax=330nm~420nm. Studies have shown that the absorption wavelength of liquid crystal molecules has a very obvious positive correlation with their refractive index. Therefore, the inverse wavelength dispersion can be implied by the λmax of the side groups. As a positively dispersed liquid crystal, M-1 generally has a λmax below 300nm. Its existence adjusts the liquid crystal properties of the entire system and the temperature of liquid crystal transition, and its dilution of the short-axis refractive index also adjusts the degree of wavelength dispersion of the system (that is, "dispersion"). The larger the ratio of M-1 / M-2, the greater the color dispersion of the anisotropic body will be, and the amount of M-1 and M-2 should be adjusted according to the optical parameter requirements of the actual application.

[0054] As a preferred embodiment, in formula M-2, L 5 ~L 8 Preferred Group; H 3 ~H 4 Preferred use Group; Z 3 ~Z 4 Preferred use Group.

[0055] As a preferred embodiment, in formula M-2, The following groups are preferably used:

[0056] That is, W 1 , W 3 , W 4 are all selected from hydrogen atoms, W 2 Selected from

[0057] Among them, B 2 Select from or m = 1-20;

[0058] R 6 Selected from Group;

[0059] D 1 Selected from N or C atoms, D 2 is selected from S or O atoms.

[0060] As a specific embodiment, the compound represented by formula M-2 may include, but is not limited to, at least one of the compounds represented by the following formulas M-2-1 to M-2-10, wherein the molecular formulas shown below all satisfy the condition of λmax=330nm to 420nm, and their λmax is marked next to them. λmax is measured using an ultraviolet-visible spectrophotometer (UV-2700i, Shimadzu):

[0061]

[0062]

[0063] In the above liquid crystal composition, M-2 may contain only one compound, or may be a combination of multiple compounds conforming to the general formula of M-2. In the liquid crystal composition of the present invention, the recommended total amount of M-2 monomers is 35 to 99 parts by weight, preferably 65 to 90 parts, and more preferably 75 to 80 parts. 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99 parts by weight or any value between these numbers.

[0064] The specific mixing ratio of the above two types of compounds M-1 and M-2 can be adjusted according to the needs of color dispersion and refractive index. In addition to M-1 and M-2, other types of polymerizable liquid crystal compounds can be added to the liquid crystal composition formula. For example, in another embodiment, the compounds shown in M-3-1 to 10 can be added to the liquid crystal composition of the present invention. The functions of these liquid crystal compounds can increase the crosslinking density, adjust the refractive index, and cause chiral phases. The amount of M-3 monomers (for example, M-3-1 to 10) added should not exceed 10 parts by weight. Specifically, the structures of the compounds M-3-1 to 10 can be as follows:

[0065]

[0066]

[0067] In order to form a cross-linked network by photoinitiated polymerization, a photoinitiator is generally required to be added to the liquid crystal composition formulation. The photoinitiator suitable for the present invention may include, but is not limited to, the compounds described in the following formulas I-1 to I-7:

[0068]

[0069]

[0070] In the liquid crystal composition of the present invention, the recommended total amount of photoinitiator is 0.2 to 10 parts by weight, preferably 3 to 7 parts. For example, in the liquid crystal composition provided by the present invention, the weight of the photoinitiator can be 0.2, 0.4, 0.6, 0.8, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 parts or any value between these numbers.

[0071] In the actual coating production process, other additives can be added as needed to ensure solution stability, leveling, photocrosslinking efficiency, etc. For example, the additives suitable for the liquid crystal composition of the present invention may include a combination of one or more of a leveling defoaming aid, an inhibitor, and a chain transfer agent. Among them, the leveling defoaming aid can be BYK-300, BYK-306, BYK-358, BYK-354, BYK-515, BYK-3560, BYK-3566 purchased from BYK; MEGAFACE F-554, F-556 purchased from DIC; and Zonyl FS-520, Zonyl 8857A purchased from DuPont. The inhibitor suitable for the present invention may include at least one of benzoquinone, hydroquinone, and 2,6-di-tert-butyl-4-methylphenol (BHT); the chain transfer agent suitable for the present invention may include at least one of dodecanethiol and triethylamine.

[0072] In the liquid crystal composition of the present invention, the recommended total amount of the additive is 0.01 to 5 parts by weight, preferably 0.1 to 1 part. For example, in the liquid crystal composition of the present invention, the weight of the additive is 0.01, 0.02, 0.04, 0.06, 0.08, 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 parts or any value between these numbers.

[0073] In the process of actually producing optical films using the liquid crystal composition formula, solvents are needed to assist in the coating process. Solvents suitable for the liquid crystal composition of the present invention mainly include benzene, ketones, esters and high polarity solvents. Benzene solvents mainly include: toluene, xylene, chlorobenzene, ethylbenzene; ketone solvents mainly include: butanone, 3-pentanone, cyclopentanone, cyclohexanone, N-methylpyrrolidone, isophorone; ester solvents mainly include: ethyl acetate, butyl acetate, propylene glycol methyl ether acetate; high polarity solvent solvents mainly include: n-butanol, isopropanol, propylene glycol methyl ether, N,N-dimethylformamide, ethanolamine, acetonitrile. In one embodiment, one solvent can be used. In another embodiment, the above solvents can be used in combination. Among them, in terms of weight parts (and calculated by non-volatile content), 100 to 1200 parts by weight of solvent can be added to the above liquid crystal composition, preferably 250 to 350 parts by weight of solvent. For example, in the above-mentioned liquid crystal composition of the present invention, 100, 200, 210, 220, 230, 240, 250, 260, 270, 280, 290, 295, 300, 305, 310, 311, 312, 313, 314, 315, 316, 317, 318, 319, 320, 325, 330, 335, 340, 350, 360, 370, 380, 390, 400, 500, 600, 700, 800, 900, 1000, 1100, 1200 parts of at least one of the above-mentioned solvents can be added in parts by weight.

[0074] In another embodiment of the present application, an anisotropic body is also provided, wherein the anisotropic body is obtained from the above-mentioned liquid crystal composition of the present application through a polymerization reaction.

[0075] In another embodiment of the present application, an optical film is provided. The optical film includes a polymerized product generated by a polymerization reaction of the liquid crystal composition described in the present application or includes the anisotropic body described in the present application.

[0076] In another embodiment of the present application, a phase difference film is also provided, which includes a polymerization product generated by a polymerization reaction of the liquid crystal composition described in the present application or includes the anisotropic body described in the present application, wherein the phase retardation R450 of the phase difference film at a wavelength of 450nm and the phase retardation R550 at a wavelength of 550nm satisfy the following condition: R450 / R550≤1.0.

[0077] The liquid crystal composition provided by the present invention is further described below in conjunction with the examples. The components or raw materials involved in the examples are obtained by conventional routes or prepared by methods known in the art, and comply with the corresponding national standards. For example, the synthesis method of the M-1 compound can refer to the patent document: CN101870651A; the synthesis method of the M-2 compound can refer to the patent document: CN107108458B.

[0078] Example

[0079] According to the formula in each embodiment and comparative example, weigh each component and solvent in the liquid crystal composition. Add each component and solvent in the reagent bottle in turn, mix by ultrasonic oscillation in a 40°C water bath until dissolved, cool to room temperature and store for later use. During the solution preparation process, no chemical reaction occurs between the components. Among them, the formula composition of each embodiment and comparative example is as follows: [Formula composition]

[0080] Example 1

[0081] Components Weight M-1-3 20 servings M-2-2 80 servings I-1 2 servings I-2 2 servings BYK-300(BYK) 0.1 part Cyclopentanone 187.3 copies Toluene 125 servings

[0082] Example 2

[0083] Components Weight M-1-5 25 servings M-2-2 55 servings M-2-7 20 servings I-1 2 servings I-2 2 servings BYK-300(BYK) 0.1 part Cyclopentanone 187.3 copies Toluene 125 servings

[0084] Example 3

[0085] Components Weight M-1-1 25 servings M-2-2 55 servings M-2-7 20 servings I-1 2 servings I-2 2 servings BYK-300(BYK) 0.1 part Cyclopentanone 187.3 copies Toluene 125 servings

[0086] Comparative Example 1

[0087] Components Weight M-3-1 20 servings M-2-2 80 servings I-1 2 servings I-2 2 servings BYK-300(BYK) 0.1 part Cyclopentanone 187.3 copies Toluene 125 servings

[0088] Comparative Example 2

[0089] Components Weight M-3-2 25 servings M-2-2 55 servings M-2-7 20 servings I-1 2 servings I-2 2 servings BYK-300(BYK) 0.1 part Cyclopentanone 187.3 copies Toluene 125 servings

[0090] Performance Testing

[0091] 1. Melting point test

[0092] After obtaining the liquid crystal composition formulas of the above Examples 1 to 3 and Comparative Examples 1 to 2, the melting point of each liquid crystal composition was tested.

[0093] A small amount of the above embodiment and comparative example solution was spread on a glass plate, and the solvent was evaporated on a heating plate at 85°C. The evaporated viscous liquid crystal material was subjected to thermal analysis test using a differential scanning calorimeter (DSC3, Mettler-Toledo). The sample amount was 6 to 15 mg, the scanning temperature range was 0 to 150°C, and the clearing point and crystallization point of each solution and monomer were recorded. The test results are shown in Table 1 below:

[0094] Table 1

[0095] Clearing point(℃) Crystallization point(℃) M-1-3 131 91.2 M-2-2 121 94 M-3-1 122 58 Example 1 134 N / A Comparative Example 1 109 N / A Example 2 140 N / A Example 3 143 N / A M-2-7 126 75 M-3-2 125 68 Comparative Example 2 114 N / A

[0096] Note: N / A means no crystallization point.

[0097] The crystallization point of the liquid crystal composition often determines the lower limit of the process temperature window in the process of preparing an optical film from the liquid crystal composition, while the clearing point of the liquid crystal composition often determines the upper limit of the process temperature window in the process of preparing an optical film from the liquid crystal composition. After reaching the clearing point, the liquid crystal will reach an isotropic state and lose its birefringence. Compared with Comparative Example 1, Example 1 uses different types of positively dispersed liquid crystal monomers, wherein Example 1 uses the M-1 monomer of the present application, while Comparative Example 1 uses the M-3 monomer, and the addition amount of the M-1 monomer and the M-3 monomer in the two embodiments is also 20%. The liquid crystal composition in Example 1 has a higher clearing point than the liquid crystal composition in Comparative Example 1, indicating that the processable temperature range of the liquid crystal composition in Example 1 is wider. No crystallization point appears in the liquid solution of the two embodiments, indicating that the addition of both monomers inhibits the crystallization behavior of the liquid crystal composition.

[0098] Similarly, the clearing points of Examples 2 and 3 are higher than that of Comparative Example 2, and are even higher than the clearing points of the selected M-1 and M-2 themselves, indicating that the use of the liquid crystal composition including M-1 and M-2 monomers provided in the present application can achieve a higher clearing point, thereby broadening the process temperature window in the process of preparing optical films using the liquid crystal composition.

[0099] 2. Color dispersion test of retardation film

[0100] 2.1 Preparation of phase difference film

[0101] Wash the 10*10cm optical glass, and evenly coat the optical alignment agent E01 (manufactured by Osaka Organic Co., Ltd.) on the glass surface using a spin coater (2300rpm, 10s). Then dry at 120°C. After cooling to room temperature, irradiate the surface with 313nm polarized ultraviolet light for 10mJ to obtain a glass substrate with an alignment layer.

[0102] On a glass substrate with an alignment layer, the above Examples 1 to 3 and Comparative Examples 1 to 2 were uniformly coated using a spin coater (600 rpm, 30 s), and the solvent was dried to evaporate. The drying temperature was slightly lower than the clearing point temperature shown in the above table. Then, the film surface with the composition was irradiated with a mercury lamp in a nitrogen atmosphere with a total energy of 1000 mJ / cm 2 , that is, a phase difference film is obtained.

[0103] 2.2 Color dispersion test

[0104] The polarization measuring instrument Axoscan was used to test the phase difference of the phase difference film at each wavelength, and the phase difference R450 at 450nm and the phase difference R550 at 550nm were taken. The color dispersion value was obtained by calculating R450 / R550. The test results are shown in Table 2 below:

[0105] Table 2

[0106] R450 / R550 Example 1 0.854 Example 2 0.954 Example 3 0.957 Comparative Example 1 0.881 Comparative Example 2 0.995

[0107] Example 1 and Comparative Example 1 use the same M-2 monomer type and M-2 weight fraction, the difference is that Example 1 uses the M-1 monomer of the present application, while Comparative Example 1 uses the M-3 monomer. Compared with Comparative Example 1, Example 1, in which the positive dispersion monomer is M-1, has a lower dispersion value, while Comparative Example 1, in which the same weight fraction of M-3 is used, has a larger dispersion value, indicating that under the same addition amount, M-1 has less influence on the dispersion value of the system. In addition, for the same M-1 type monomer, the more the added amount, the greater the dispersion value (for example, reference URL: doi.org / 10.1039 / d1tc05068k), and relative to Comparative Example 1 in which M-3 is added, under the same added amount, M-1 has less effect on the dispersion value of the system. Therefore, by using the M-1 monomer of the present invention, the liquid crystal composition can add a larger proportion of positive dispersion monomers while maintaining the wavelength dispersion of the optical film system (R450 / R550 value), and the clearing point (Tni) temperature of the composite system is higher, which is beneficial to broaden the processing temperature window and reduce manufacturing costs.

[0108] Similarly, different M-1 and M-3 positive dispersion monomers are used in Examples 2 and 3 and Comparative Example 2, but both are 25 parts by weight. The color dispersion value of the comparative example is close to 1, while the color dispersion values ​​of Examples 2 and 3 are both lower, indicating that the reverse wavelength dispersion of the liquid crystal compositions of Examples 2 and 3 of the present application is better.

[0109] In summary, the liquid crystal composition provided by the present invention can contain a larger proportion of positive dispersion monomers while maintaining the wavelength dispersion of the optical film system (R450 / R550 value), and the clearing point (Tni) temperature of the composition system can be higher, which is beneficial to broaden the processing temperature window and reduce manufacturing costs.

[0110] The above embodiments of the present invention focus on the differences between the various embodiments. As long as the different optimization features between the various embodiments are not contradictory, they can be combined to form a better embodiment. Considering the simplicity of the text, they will not be repeated here.

[0111] The above description is only an embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A liquid crystal composition, characterized in that: In parts by weight, it comprises 1 to 50 parts of the compound represented by formula M-1 and 35 to 99 parts of the compound represented by formula M-2; Wherein, in formula M-1 and formula M-2, L1 to L8 are each independently selected from Group; In formula M-1, H1 to H2 are each independently selected from Group; In formula M-1 and formula M-2, Z1 to Z4 and H3 to H4 are each independently selected from Group; In formula M-1 and formula M-2, J1 to J4 are each independently selected from a radical or a single bond; In formula M-1 and formula M-2, Y1 to Y4 are each independently selected from an alkyl chain *-(CH2) n -*, wherein n=2 to 20 and the values ​​of n in the alkyl chains of Y1 to Y4 are the same or different; In formula M-1 and formula M-2, R1 to R4 are each independently selected from Group; In formula M-1, X1 to X4 may represent a hydrogen atom, a halogen atom or a functional group as shown below: Wherein, A1 and A2 are any saturated alkane chains having 1 to 20 carbon atoms; B1 is each independently selected from *-(CH2) n -* or *-(CH2CH2O) n -*, n=1-20; R5 is selected from Group; In formula M-2, W1 to W4 are each independently a λ max = Any organic group with a molecular weight of 330 nm to 420 nm.

2. The liquid crystal composition according to claim 1, characterized in that: The compound represented by formula M-1 includes at least one of the compounds represented by the following formulae M-1-1 to M-1-14:

3. The liquid crystal composition according to claim 1, characterized in that: The compound represented by formula M-2 includes at least one of the compounds represented by the following formulae M-2-1 to M-2-10:

4. The liquid crystal composition according to claim 1, characterized in that: The liquid crystal composition further comprises 0.2 to 10 parts by weight of an initiator, wherein the initiator comprises at least one of the compounds represented by the following formulae I-1 to I-7:

5. The liquid crystal composition according to claim 4, characterized in that: In parts by weight, the liquid crystal composition comprises 10 to 30 parts of the compound represented by formula M-1, 65 to 90 parts of the compound represented by formula M-2, and 3 to 7 parts of the initiator represented by formulas I-1 to I-7.

6. The liquid crystal composition according to claim 1, characterized in that: The liquid crystal composition further comprises 0.01 to 5 parts of an auxiliary agent in parts by weight, wherein the auxiliary agent comprises a combination of one or more of a leveling and defoaming auxiliary agent, an inhibitor, and a chain transfer agent; in: The leveling and defoaming aid includes at least one of BYK-300, BYK-306, BYK-358, BYK-354, BYK-515, BYK-3560, BYK-3566, MEGAFACE F-554, F-556, Zonyl FS-520, and Zonyl 8857A; The polymerization inhibitor includes at least one of benzoquinone, hydroquinone, and 2,6-di-tert-butyl-4-methylphenol; The chain transfer agent includes at least one of dodecanethiol and triethylamine.

7. The liquid crystal composition according to claim 1, characterized in that: The liquid crystal composition further comprises 100 to 1200 parts by weight of a solvent, wherein the solvent comprises at least one of the following: Toluene, xylene, chlorobenzene, ethylbenzene, butanone, 3-pentanone, cyclopentanone, cyclohexanone, N-methylpyrrolidone, isophorone, ethyl acetate, butyl acetate, propylene glycol methyl ether acetate, n-butanol, isopropanol, propylene glycol methyl ether, N,N-dimethylformamide, ethanolamine, acetonitrile.

8. An anisotropic body, characterized in that: Obtained by polymerizing the liquid crystal composition according to any one of claims 1 to 7.

9. An optical film, characterized in that: The optical film comprises a polymerization product of the liquid crystal composition according to any one of claims 1 to 7 or comprises the anisotropic body according to claim 8 .

10. A phase difference film, characterized in that: The phase difference film comprises a polymerized product of the liquid crystal composition according to any one of claims 1 to 7 or comprises the anisotropic body according to claim 8, wherein the phase retardation R450 of the phase difference film at a wavelength of 450 nm and the phase retardation R550 at a wavelength of 550 nm satisfy the following conditions: R450 / R550≤1.0.

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