Cellulose derivatives, liquid crystal materials, liquid crystal films, and methods for manufacturing liquid crystal films

Abstract

To provide a cellulose derivative capable of forming a liquid crystal film with novel polarization properties.SOLUTION: A cellulose derivative comprises hydroxy groups, with some of the hydroxy groups being substituted with groups having unsaturated double bonds and alkyl groups.SELECTED DRAWING: None

Description

[Technical Field]

[0001] This disclosure relates to cellulose derivatives, liquid crystal materials, liquid crystal films, and methods for manufacturing liquid crystal films. [Background technology]

[0002] Liquid crystal materials are not only used as display materials for liquid crystal displays, but in recent years, their optical properties have led to their application in photonic devices. Cellulose derivatives are known as liquid crystal materials.

[0003] As a cellulose derivative possessing liquid crystalline properties, a cellulose derivative has been disclosed in which a substituent having a carbamate group (urethane bond) is introduced to the hydrogen atom of the hydroxyl group of hydroxypropyl cellulose (see, for example, Patent Document 1).

[0004] A lyotropic liquid crystal material has been disclosed that exhibits a large change in wavelength during compression when a film is formed, and also has excellent stretchability when a film is formed, and which contains a crosslinkable cellulose derivative and a monomer having a group with an unsaturated double bond in its molecule (see, for example, Patent Document 2). [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2015-48365 [Patent Document 2] International Publication No. 2019 / 151360 [Overview of the project] [Problems that the invention aims to solve]

[0006] Hydroxypropyl cellulose (HPC), ethyl cellulose (EC), and others are cellulose derivatives that are the main components of paper, cotton, and pulp. They are also highly versatile polymers used in pharmaceuticals, supplements, and other applications because they are harmless to humans and the environment. Furthermore, cellulose is an inexpensive material because it is the most abundant raw material in nature. Therefore, the development of liquid crystal materials using cellulose derivatives as raw materials is useful from the standpoint of safety and reducing environmental impact, and further utilization of the liquid crystal properties and optical properties of cellulose derivatives in liquid crystal materials, liquid crystal films, photonic devices, etc., is expected.

[0007] The elastomer film formed from the liquid crystal material disclosed in Patent Document 2 forms a molecular helical structure in which rod-shaped liquid crystal molecules are stacked while changing their orientation, and exhibits an excellent cholesteric liquid crystal orientation state. This elastomer film Bragg reflects circularly polarized light in the same direction as the palmarity of the helix. Specifically, an elastomer film composed of a hydroxypropyl cellulose derivative and exhibiting a cholesteric liquid crystal orientation state Bragg reflects right-circularly polarized light.

[0008] As mentioned above, the liquid crystalline properties and optical characteristics of cellulose derivatives are expected to be further utilized in liquid crystal materials, liquid crystal films, photonic devices, etc., and it is desirable to develop cellulose derivatives that can form liquid crystal films with novel polarization properties.

[0009] This disclosure aims to provide a cellulose derivative and a liquid crystal material capable of forming a liquid crystal film having novel polarization properties, a liquid crystal film obtained by curing this liquid crystal material, and a method for manufacturing a liquid crystal film using this liquid crystal material. [Means for solving the problem]

[0010] The means for solving the aforementioned problems include the following embodiments. <1> A cellulose derivative containing hydroxyl groups, wherein some of the hydroxyl groups are substituted with groups having unsaturated double bonds and alkyl groups. <2> The group having the unsaturated double bond is a group having a (meth)acryloyl group. <1> Cellulose derivatives as described above. <3> The alkyl group is an ethyl group and contains an ethylcellulose skeleton. <1> or <2> Cellulose derivatives as described above. <4> A cellulose derivative in which at least a portion of the hydroxyl groups are substituted with acyl groups, Polymerizable monomers containing a group having an unsaturated double bond, A liquid crystal material for forming a liquid crystal film having both left-circularly polarized and right-circularly polarized reflection properties, including [a specific element]. <5> The cellulose derivative comprises a hydroxyalkylcellulose skeleton. <4> The liquid crystal materials described above. <6> <1> ~ <3> A cellulose derivative described in any one of the following, Polymerizable monomers containing a group having an unsaturated double bond, Liquid crystal materials containing [specific material]. <7> For forming a liquid crystal film having both left-circular polarization and right-circular polarization reflection characteristics. <6> The liquid crystal materials described above. <8> <4> ~ <7> A liquid crystal film obtained by curing one of the following liquid crystal materials, having both left-circularly polarized and right-circularly polarized reflection properties. <9> <4> ~ <7> A liquid crystal film comprising a liquid crystal material described in any one of the above, and including a region in which retardation is 200 nm or more. <10> <4> ~ <7> A liquid crystal film having a thickness of 200 μm or more, obtained by curing one of the liquid crystal materials described in any one of the above. <11> <4> ~ <7> A shearing process in which a shear force is applied to the liquid crystal material described in any one of the following, An orientation step in which the liquid crystal material after the shearing step is left to stand and orient, A curing step for curing the liquid crystal material after the orientation step, A method for manufacturing a liquid crystal film containing [a specific component]. [Effects of the Invention]

[0011] This disclosure provides a cellulose derivative and a liquid crystal material capable of forming a liquid crystal film having novel polarization properties, a liquid crystal film obtained by curing this liquid crystal material, and a method for manufacturing a liquid crystal film using this liquid crystal material. [Brief explanation of the drawing]

[0012] [Figure 1] Figure 1(a) shows the change in the transmission spectrum of left-circularly polarized light when a liquid crystal film 1 is fabricated using liquid crystal material 1 under the condition of a shear rate of 0.2 s⁻¹, and Figure 1(b) shows the change in the transmission spectrum of right-circularly polarized light in this case. [Figure 2] Figure 2(a) shows the change in the transmission spectrum of left-circularly polarized light when a liquid crystal film 1 is fabricated using liquid crystal material 1 under the condition of a shear rate of 0.5 s⁻¹, and Figure 2(b) shows the change in the transmission spectrum of right-circularly polarized light in this case. [Figure 3] Figure 3(a) shows the change in the transmission spectrum of left-circularly polarized light when a liquid crystal film 2 is fabricated using liquid crystal material 2 under the condition of a shear rate of 0.2 s⁻¹, and Figure 3(b) shows the change in the transmission spectrum of right-circularly polarized light in this case. [Figure 4] Figure 4(a) shows the change in the transmission spectrum of left-circularly polarized light when a liquid crystal film 3 is fabricated using liquid crystal material 3 under the condition of a shear rate of 0.5 s⁻¹, and Figure 4(b) shows the change in the transmission spectrum of right-circularly polarized light in this case. [Figure 5] Figure 5(a) shows the change in the transmission spectrum of left-circularly polarized light when a liquid crystal film 4 is made using liquid crystal material 2 and the waiting time after shear orientation treatment is 200 seconds, and Figure 5(b) shows the change in the transmission spectrum of right-circularly polarized light in this case. [Figure 6] Figure 6(a) shows the change in the transmission spectrum of left-circularly polarized light when a liquid crystal film 5 is made using liquid crystal material 4, and Figure 6(b) shows the change in the transmission spectrum of right-circularly polarized light in this case. [Figure 7]Figure 7(a) shows the change in the transmission spectrum of left-circularly polarized light when a liquid crystal film 6 is made using liquid crystal material 5, and Figure 7(b) shows the change in the transmission spectrum of right-circularly polarized light in this case. [Figure 8] Figure 8(a) shows the change in the transmission spectrum of left-circularly polarized light when a liquid crystal film 7 is made using liquid crystal material 6, and Figure 8(b) shows the change in the transmission spectrum of right-circularly polarized light in this case. [Figure 9] Figure 9(a) shows the change in the transmission spectrum of left-circularly polarized light when a liquid crystal film 8 (thickness of liquid crystal film 8: 560 μm) is made using liquid crystal material 7, and Figure 9(b) shows the change in the transmission spectrum of right-circularly polarized light in this case. [Figure 10] Figure 10(a) shows the change in the transmission spectrum of left-circularly polarized light when a liquid crystal film 9 (thickness of liquid crystal film 9: 178 μm) is made using liquid crystal material 7, and Figure 10(b) shows the change in the transmission spectrum of right-circularly polarized light in this case. [Figure 11] Figure 11 shows the relationship between the distance from the center in a planar view and birefringence for liquid crystal films 8 and 9. [Figure 12] Figure 12 shows the relationship between the distance from the center in a planar view and retardation for liquid crystal film 8 and liquid crystal film 9. [Figure 13] Figures 13(a) to 13(f) show the changes in the right-circularly polarized and left-circularly polarized spectra of liquid crystal films 12-6 to 12-1 at r=3mm or r=9mm, respectively. [Figure 14] Figure 14 shows the relationship between the distance from the center in a planar view and retardation for liquid crystal films 12-1 to 12-6. [Figure 15] Figure 15 shows the relationship between the distance from the center in a planar view and birefringence for liquid crystal films 12-1 to 12-6. [Figure 16] Figure 16 shows the relationship between retardation and the ratio of the peak intensities of left and right circularly polarized light for liquid crystal films 12-1 to 12-6. [Figure 17] Figures 17(a) and 17(b) show the changes in the right-circularly polarized and left-circularly polarized spectra of liquid crystal films 13-1 and 13-2 at r=3mm and r=9mm, respectively. [Figure 18] Figure 18 shows the relationship between the distance from the center in a planar view and retardation for liquid crystal films 13-1 and 13-2. [Figure 19] Figure 19 shows the relationship between the distance from the center in a planar view and birefringence for liquid crystal films 13-1 and 13-2. [Figure 20] Figure 20 shows the relationship between retardation and the ratio of the peak intensities of left and right circularly polarized light for liquid crystal films 13-1 and 13-2. [Figure 21] Figures 21(a) and 21(b) show the changes in the right-circularly polarized and left-circularly polarized spectra of liquid crystal films 14-1 and 14-2 at r=3mm and r=9mm, respectively. [Figure 22] Figure 22 shows the relationship between the distance from the center in a planar view and retardation for liquid crystal films 14-1 and 14-2. [Figure 23] Figure 23 shows the relationship between the distance from the center in a planar view and birefringence for liquid crystal films 14-1 and 14-2. [Figure 24] Figure 24 shows the relationship between retardation and the ratio of the peak intensities of left and right circularly polarized light for liquid crystal films 14-1 and 14-2. [Figure 25] Figures 25(a) and 25(b) show the changes in the left-circularly polarized and right-circularly polarized spectra of the liquid crystal film 15 at r=0mm, 3mm, 6mm, and 9mm, respectively. [Figure 26] Figure 26 shows the change in the left-circularly polarized spectrum of the liquid crystal film 15 from r=0mm to 5mm. [Figure 27] Figure 27 shows the relationship between the distance from the center in a planar view and retardation for the liquid crystal film 15. [Figure 28]Figures 28(a) and 28(b) show the change in the left circularly polarized spectrum of liquid crystal films 16-18 at r=4mm or r=9mm, while Figures 28(c) and 28(d) show the change in the right circularly polarized spectrum of liquid crystal films 16-18 at r=4mm or r=9mm. [Figure 29] Figure 29 shows the relationship between the distance from the center in a planar view and retardation for liquid crystal films 16-18. [Figure 30] This figure shows the measurement results of the circularly polarized transmission spectrum in Reference Example 1. [Figure 31] Figure 31(a) shows the change in the transmission spectrum of left-circularly polarized light when a liquid crystal film A is made using liquid crystal material A and subjected to shear orientation treatment, and Figure 31(b) shows the change in the transmission spectrum of right-circularly polarized light in this case. [Figure 32] Figure 32 shows the changes in the transmission spectra of left-circularly polarized and right-circularly polarized light when a liquid crystal film B is made using liquid crystal material A and has not undergone shear orientation treatment. [Modes for carrying out the invention]

[0013] In this disclosure, a numerical range represented by "~" means a range that includes the numbers before and after "~" as the lower and upper limits. In numerical ranges described in stages in this disclosure, the upper or lower limit described in one numerical range may be replaced with the upper or lower limit of another numerical range described in stages. Also, in numerical ranges described in this disclosure, the upper or lower limit described in one numerical range may be replaced with the values ​​shown in the examples.

[0014] In this disclosure, "(meth)acrylic" means at least one of "acrylic" and "methacrylic," "(meth)acrylate" means at least one of "acrylate" and "methacrylate," and "(meth)acryloyl" means at least one of "acryloyl" and "methacryloyl." Examples of substituents in this disclosure include linear or branched alkyl groups having 1 to 6 carbon atoms, cycloalkyl groups having 3 to 6 carbon atoms, aryl groups having 6 to 12 carbon atoms, and halogen atoms. If there are two or more substituents, each substituent may be the same or different.

[0015] [Cellulose derivatives] The cellulose derivatives of this disclosure contain hydroxyl groups, and some of the hydroxyl groups are substituted with groups having unsaturated double bonds and alkyl groups. By using a liquid crystal material containing the cellulose derivatives of this disclosure to produce a liquid crystal film, it is possible to form a liquid crystal film having novel polarization properties. For example, by applying a shear force to the liquid crystal material to orient the cellulose derivative contained in the liquid crystal material, and then curing the liquid crystal material, it is possible to form a liquid crystal film having both left-circularly polarized and right-circularly polarized reflection properties.

[0016] The cellulose derivatives of this disclosure are crosslinkable cellulose derivatives having an alkyl group, such as a crosslinkable ethylcellulose derivative. A liquid crystal film composed of a liquid crystal material containing the cellulose derivative exhibits a cholesteric liquid crystal orientation state that forms a molecular helical structure, and selectively reflects left-circularly polarized light when white light is irradiated perpendicularly to the orientation surface.

[0017] On the other hand, by applying a shear force to a liquid crystal material containing the cellulose derivative, the cellulose derivative contained in the liquid crystal material is oriented, and then the liquid crystal material is cured, a liquid crystal film with a tilted molecular helical structure can be obtained. When white light is shone perpendicularly to the orientation surface while the molecular helical structure is tilted, both left-circularly polarized and right-circularly polarized light are reflected. This is presumed to be similar to the mechanism by which both left-circularly polarized and right-circularly polarized light are reflected when white light is obliquely incident on the orientation surface.

[0018] Furthermore, applying shear force to liquid crystal materials containing cellulose derivatives tends to cause molecules to orient in the shear direction, increasing birefringence. In liquid crystal films with increased birefringence, some of the incident right-circularly polarized light is more likely to change to left-circularly polarized light, and some of the reflected left-circularly polarized light is more likely to change to right-circularly polarized light. As a result, it is presumed that both the reflected left-circularly polarized light and the changed right-circularly polarized light can be observed as reflected light.

[0019] The following describes preferred forms of the cellulose derivatives of this disclosure (hereinafter also referred to as the "first cellulose derivative").

[0020] The first cellulose derivative has a hydroxyl group, a hydroxyl group hydrogen atom This is a cellulose derivative containing a group having an unsaturated double bond in which part is substituted, and an alkyl group. Preferably, the hydroxyl group contained in the cellulose derivative is a hydroxyl group bonded to the 2nd, 3rd, or 6th position of the constituent unit of the cellulose skeleton.

[0021] The unsaturated double bond-containing groups in the first cellulose derivative are not particularly limited, and examples include groups having a (meth)acryloyl group, vinyl group, allyl group, vinyloxy group, isopropenyl group, 1-propenyl group, 2-butenyl group, 3-butenyl group, 1,3-butadienyl group, 2-pentenyl group, geranyl group, oleyl group, cycloalkenyl group (e.g., 2-cyclopenten-1-yl group, 2-cyclohexen-1-yl group), vinylbenzyl group, cinnamyl group, etc. From the viewpoint of obtaining a liquid crystal film with appropriate elasticity by crosslinking, the unsaturated double bond-containing group is preferably a group having a (meth)acryloyl group.

[0022] The group having a (meth)acryloyl group is preferably a group represented by at least one of the following general formulas (1C) and (2C).

[0023] [ka]

[0024] In general formula (1C), R 1C X represents a hydrogen atom or a methyl group. 18 p1 represents a single bond, a linear or branched alkylene group having 1 to 18 carbon atoms, a cycloalkylene group having 3 to 18 carbon atoms, an arylene group having 6 to 18 carbon atoms, or a linking group consisting of one or more groups selected from the group consisting of -O-, -NH-, -S-, and -C(=O)-, and p1 represents an integer of 1 or 2. However, X 18 The valence of is p1+1. ** represents the part that bonds with the oxygen atom at position 2, 3, or 6 in the cellulose backbone.

[0025] X 18 The linear or branched alkylene group, cycloalkylene group, and arylene group represented by may have substituents.

[0026] X 18 There are no particular restrictions on the arylene group having 6 to 18 carbon atoms represented by , and examples include phenylene groups and naphthalene groups.

[0027] X 18 There are no particular restrictions on the linking group, which consists of one or more linked groups selected from the group consisting of -O-, -NH-, -S-, and -C(=O)- represented by . Examples include "-C(=O)-NH-(CH2)2-O-", "-C(=O)-NH-(CH2)2-O-(CH2)2-O-", and "-C(=O)-NH-C(CH3)-(CH2-O-)2".

[0028] From the viewpoint of crosslinking reactions, it is preferable that p1 in general formula (1C) is an integer of 1.

[0029] In general formula (1C), R 1C X is a hydrogen atom or a methyl group, 18 When the bond is a single bond and p1 is 1, the group represented by the general formula (1C) is a (meth)acryloyl group.

[0030] An example of the group represented by the general formula (1C) is shown below. The group represented by the general formula (1C) is not limited thereto. In the following general formulas (1C-1) to (1C-8), * represents a portion bonded to an oxygen atom at the 2-position, 3-position, or 6-position in the constituent unit of the cellulose skeleton.

[0031] [Chemical formula]

[0032] [Chemical formula]

[0033] In the group represented by the general formula (1C-5), in the group represented by the general formula (1C), X 18 is a trivalent linking group represented by the following general formula (1C-7), R 1C is a hydrogen atom, and p1 is 2. In the general formula (1C-7), *** represents a portion bonded to the carbon atom bonded to the CO of (COCH=CH2) in the general formula (1C-5) above.

[0034] [Chemical formula]

[0035] [Chemical formula]

[0036] [Chemical formula]

[0037] In the general formula (2C), R 1D represents a linear or branched alkylene group having 1 to 18 carbon atoms, and p1 and * are synonymous with p1 and * in the general formula (1C) above.

[0038] From the viewpoint of obtaining a liquid crystal film with appropriate elasticity through crosslinking, R 1D The linear or branched alkylene group having 1 to 18 carbon atoms represented by is preferably a linear or branched alkylene group having 3 to 18 carbon atoms, more preferably a linear alkylene group having 3 to 18 carbon atoms, and even more preferably a linear alkylene group having 6 to 12 carbon atoms.

[0039] From the viewpoint of crosslinking reactions, it is preferable that p1 in general formula (2C) is an integer of 1.

[0040] The following are examples of groups represented by the general formula (2C). The groups represented by the general formula (2C) are not limited to these examples. In general formulas (2C-1) to (2C-4) below, ** represents the part that bonds with the oxygen atom at position 2, 3, or 6 in the constituent unit of the cellulose skeleton.

[0041] [ka]

[0042] The alkyl group included in the first cellulose derivative is not particularly limited, and examples include alkyl groups having 1 to 18 carbon atoms. The alkyl group having 1 to 18 carbon atoms may be a linear, branched, or cyclic alkyl group, and may be unsubstituted or substituted. Examples of unsubstituted alkyl groups having 1 to 18 carbon atoms include methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, and tert-butyl groups. Examples of unsubstituted cyclic alkyl groups having 3 to 18 carbon atoms include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, methylcyclopentyl, methylcyclohexyl, and methylcycloheptyl groups. The alkyl group contained in the first cellulose derivative is preferably an alkyl group that is bonded to the oxygen atom at the 2nd, 3rd, or 6th position of the constituent unit of the cellulose skeleton.

[0043] The alkyl group is preferably an ethyl group, and the first cellulose derivative preferably contains an ethylcellulose skeleton.

[0044] The first cellulose derivative preferably contains a structural unit represented by the following general formula (A).

[0045] [ka]

[0046] In general formula (A), R1, R2, and R3 are each independent of each other. hydrogen atom , represents a group having an unsaturated double bond or an alkyl group. The first cellulose derivative preferably contains a plurality of structural units represented by the above general formula (A). The plurality of structural units represented by the above general formula (A) may be the same or different from one another.

[0047] When the first cellulose derivative contains a structural unit represented by the above general formula (A), the degree of substitution of the group having an unsaturated double bond per structural unit may be 0.01 to 0.3, 0.01 to 0.2, or 0.01 to 0.1. The degree of substitution of groups having unsaturated double bonds per constituent unit is the value obtained by dividing the total number of groups having unsaturated double bonds S (total number of groups having unsaturated double bonds represented by R1, R2, or R3) contained in all constituent units of the first cellulose derivative by the total number of constituent units N of the first cellulose derivative (S / N, upper limit 3).

[0048] When the first cellulose derivative contains a structural unit represented by the above general formula (A), the degree of alkyl group substitution per structural unit may be 1.5 to 2.9, 2.0 to 2.8, or 2.3 to 2.7. The degree of alkyl group substitution per constituent unit is the value obtained by dividing the total number of alkyl groups T (total number of groups having unsaturated double bonds represented by R1, R2, or R3) contained in all constituent units of the first cellulose derivative by the total number of constituent units N of the first cellulose derivative (T / N, upper limit 3).

[0049] The degree of substitution of groups with unsaturated double bonds per constituent unit and the degree of substitution of alkyl groups per constituent unit are: 1 The values ​​may also be calculated from the integral values ​​of the characteristic proton peaks of each substituent using 1H-NMR.

[0050] [Liquid crystal materials] (First Embodiment) The liquid crystal material of the first embodiment of this disclosure comprises the first cellulose derivative described above and a polymerizable monomer containing a group having an unsaturated double bond, as described below. The liquid crystal material of the first embodiment is preferably used to form a liquid crystal film having both left-circularly polarized and right-circularly polarized reflection properties.

[0051] The content of the first cellulose derivative may be 30% to 70% by mass, 35% to 65% by mass, or 40% to 60% by mass, relative to the total mass of the liquid crystal material.

[0052] (Second Embodiment) The liquid crystal material may contain cellulose derivatives other than the first cellulose derivative described above. The liquid crystal material of the second embodiment of this disclosure contains hydroxyl groups hydrogen atom This liquid crystal material for forming a liquid crystal film having both left-circularly polarized and right-circularly polarized reflection properties comprises a cellulose derivative in which at least a portion is substituted with an acyl group (hereinafter also referred to as the "second cellulose derivative") and a polymerizable monomer containing a group having an unsaturated double bond, as described below.

[0053] By using the liquid crystal material of the second embodiment to produce a liquid crystal film, it is possible to form a liquid crystal film having novel polarization characteristics. For example, by applying a shear force to the liquid crystal material to orient the cellulose derivative contained in the liquid crystal material, and then curing the liquid crystal material, it is possible to form a liquid crystal film having both left-circular polarization and right-circular polarization reflection characteristics.

[0054] The second cellulose derivative contained in the liquid crystal material of the second embodiment is a cellulose derivative having an acyl group, such as a hydroxypropyl cellulose derivative substituted with an acyl group. A liquid crystal film composed of the liquid crystal material containing the second cellulose derivative exhibits a cholesteric liquid crystal orientation state that forms a molecular helical structure, and selectively reflects right-circularly polarized light when white light is irradiated perpendicularly to the orientation surface.

[0055] On the other hand, by applying a shear force to a liquid crystal material containing a second cellulose derivative to orient the second cellulose derivative contained in the liquid crystal material, and then curing the liquid crystal material, a liquid crystal film with a tilted molecular helical structure can be obtained. When white light is shone perpendicularly to the orientation surface while the molecular helical structure is tilted, both left-circularly polarized and right-circularly polarized light are reflected.

[0056] Furthermore, applying a shear force to a liquid crystal material containing a second cellulose derivative tends to cause the molecules to orient in the shear direction, increasing birefringence. In a liquid crystal film with increased birefringence, some of the incident left-circularly polarized light is more likely to change to right-circularly polarized light, and some of the reflected right-circularly polarized light is more likely to change to left-circularly polarized light. As a result, it is presumed that both the reflected right-circularly polarized light and the changed left-circularly polarized light can be observed as reflected light.

[0057] The preferred form of the second cellulose derivative will be described below.

[0058] <Second cellulose derivative> The second cellulose derivative is a cellulose derivative in which at least a portion of the hydroxyl groups are substituted with acyl groups, some of the hydroxyl groups may remain, all of the hydroxyl groups may be substituted with acyl groups, or all of the hydroxyl groups may be substituted with acyl groups and groups having unsaturated double bonds.

[0059] Examples of acyl groups included in the second cellulose derivative include acetyl groups, propionyl groups (propanoyl groups), butyryl groups, isobutyryl groups, hexanoyl groups, octanoyl groups, and benzoyl groups.

[0060] In the second cellulose derivative, the hydroxyl group hydrogen atom A portion of the group may be substituted with a group having an unsaturated double bond. The preferred form of the group having an unsaturated double bond is the same as the preferred form of the group having an unsaturated double bond contained in the first cellulose derivative described above.

[0061] The second cellulose derivative preferably contains a structural unit represented by the following general formula (B).

[0062] [ka]

[0063] In general formula (B), X 11 , X 12 and X 13 These are, independently, a single bond, an alkylene group, and -(R 14 -O) h -, or -C(=O)-R 15 - represents R 11 , R 12 and R 13 Each of these independently represents a hydrogen atom, a group having an unsaturated double bond, or an acyl group, and R 14 and R 15 Each of these independently represents an alkylene group, and h represents an integer between 1 and 10 (inclusive).

[0064] The second cellulose derivative preferably contains multiple constituent units represented by the general formula (B). The multiple constituent units represented by the general formula (B) may be the same or different from one another.

[0065] In general formula (B), X 11 , X 12 and X 13 The alkylene group represented by is not limited. Examples of alkylene groups include linear or branched alkylene groups having 1 to 18 carbon atoms (preferably 1 to 12) and cyclic cycloalkylene groups having 3 to 18 carbon atoms (preferably 3 to 12). Examples of linear or branched alkylene groups include methylene groups, ethylene groups, n-propylene groups, isopropylene groups, n-butylene groups, isobutylene groups, sec-butylene groups, tert-butylene groups, n-pentylene groups, isopentylene groups, and the like. Examples of cyclic alkylene groups include cyclopentylene groups and cyclohexylene groups.

[0066] In general formula (B), -(R 14 -O) h - The alkylene group (-R) in the group represented by - 14 -) is the above X 11 , X 12 and X 13 Similar alkylene groups can be cited. -(R 14 -O) h Examples of these include ethyleneoxy groups, polyethyleneoxy groups, propyleneoxy groups, and polypropyleneoxy groups. -(R 14 -O) h - More specifically, -(-O-(CH2) n -) h It can be represented by -, where n is an integer between 1 and 5 (inclusive).

[0067] In general formula (B), h is preferably 1 to 6, more preferably 1 to 4, and even more preferably 1 to 3, from the viewpoint of obtaining a liquid crystal film with appropriate elasticity through crosslinking.

[0068] In general formula (B), X 11 , X 12 and X 13 -C(=O)-R 15 - The alkylene group (-R) in the group represented by - 15 -) is the above X 11 , X 12 and X 13 Similar alkylene groups can be cited. -C(=O)-R 15 Examples of - include -C(=O)-CH2-, -C(=O)-C2H4-, and -C(=O)-C3H6-.

[0069] Alkylene group, -(R 14 -O) h -, and -C(=O)-R 15 - may have substituents.

[0070] In general formula (B), R 11 , R 12 and R 13 The preferred form of the group having an unsaturated double bond, represented by , is the same as the preferred form of the group having an unsaturated double bond contained in the first cellulose derivative described above.

[0071] In general formula (B), R 11 , R 12 and R 13 Examples of acyl groups represented by this symbol include acetyl, propionyl (propanoyl), butyryl, isobutyryl, hexanoyl, octanoyl, and benzoyl groups.

[0072] The constituent unit represented by general formula (B) is preferably the constituent unit represented by the following general formula (B-1).

[0073] [ka]

[0074] In general formula (B-1), R 1 This represents -CH2-CH2- or -CH2-CH(CH3)-, and R 11 , R 12 and R 13 Each of these independently represents a hydrogen atom, a group having an unsaturated double bond, or an acyl group, and each of m1, t1, and r1 independently represents an integer between 0 and 10.

[0075] In general formula (B-1), R 11 , R 12 and R 13 R in general formula (B) 11 , R 12 and R 13 It is synonymous with [the above]. In general formula (B-1), m1, t1, and r1 are, from the viewpoint of ease of synthesis of cellulose derivatives, preferably 0 to 8, more preferably 0 to 5, and even more preferably 0 to 3, independently of each other.

[0076] When the second cellulose derivative contains a structural unit represented by the above general formula (B), the degree of substitution of the acyl group per structural unit may be 2.00 to 3.00, 2.30 to 2.98, 2.50 to 2.95, or 2.60 to 2.95. The degree of substitution of acyl groups per constituent unit is the total number of acyl groups contained in all constituent units of the second cellulose derivative S'(R 11 , R 12 or R 13 This value (S' / N', upper limit 3) is obtained by dividing the total number of acyl groups represented by by the total number of constituent units N' of the second cellulose derivative.

[0077] If the second cellulose derivative contains a structural unit represented by the above general formula (B), and some of the hydroxyl groups are substituted with groups having unsaturated double bonds, the degree of substitution of groups having unsaturated double bonds per structural unit may be 0.01 to 0.3, 0.01 to 0.2, or 0.01 to 0.1. The degree of substitution of groups with unsaturated double bonds per constituent unit is the total number of groups with unsaturated double bonds contained in all constituent units of the second cellulose derivative T'(R 11 , R 12 or R 13 This is the value obtained by dividing the total number of groups having unsaturated double bonds (represented by ) by the total number of constituent units N' of the second cellulose derivative (T' / N', upper limit 3).

[0078] The sum of the degree of substitution of acyl groups per constituent unit and the degree of substitution of groups having unsaturated double bonds per constituent unit is not particularly limited and may be 2.00 or more, 2.40 or more, and may be 2.70 or more, or 2.80 or more, from the viewpoint of reducing the viscosity of the liquid crystal material due to the reduction of hydrogen bonds and the polarization properties.

[0079] The degree of substitution of acyl groups per constituent unit and the degree of substitution of groups having unsaturated double bonds per constituent unit are, 1 The values ​​may also be calculated from the integral values ​​of the characteristic proton peaks of each substituent using 1H-NMR.

[0080] The second cellulose derivative preferably contains a hydroxyalkylcellulose skeleton, more preferably a hydroxypropylcellulose skeleton, and when the second cellulose derivative contains a structural unit represented by general formula (B-1), R in general formula (B-1) 1 It is even more preferable that it be -CH2-CH(CH3)-.

[0081] The content of the second cellulose derivative may be 50% to 99% by mass, 60% to 95% by mass, or 70% to 90% by mass, relative to the total mass of the liquid crystal material.

[0082] <Polymerizable monomers> The liquid crystal material of the first embodiment and the liquid crystal material of the second embodiment each independently contain a polymerizable monomer (hereinafter also referred to as "polymerizable monomer") that contains a group having an unsaturated double bond.

[0083] The polymerizable monomer is not particularly limited as long as it is compatible with at least one of the first cellulose derivative and the second cellulose derivative (hereinafter also referred to as the "specific cellulose derivative") and can exhibit lyotropic liquid crystal properties when compatible with the specific cellulose derivative.

[0084] One method for confirming the compatibility between polymerizable monomers and specific cellulose derivatives is to mix the polymerizable monomers and the specific cellulose derivatives in a ratio of, for example, 1:3, stir them for about a week using a mix rotor (a product of DLAB Scientific Instrument Inc.), and visually check for the presence or absence of precipitate to determine compatibility.

[0085] Furthermore, when a specific cellulose derivative and a polymerizable monomer are compatible, one method for confirming the emergence of lyotropic liquid crystalline properties is to visually check whether a mixture of the specific cellulose derivative and the polymerizable monomer exhibits Bragg reflection.

[0086] The groups containing unsaturated double bonds in polymerizable monomers are not particularly limited as long as they can undergo polymerization reactions, and examples include (meth)acryloyl groups, vinyl groups, and aryl groups. From the viewpoint of polymerization reactivity and compatibility with specific cellulose derivatives, the group having an unsaturated double bond is preferably a (meth)acryloyl group, and more preferably an acryloyl group.

[0087] When the polymerizable monomer is a monomer containing a (meth)acryloyl group (hereinafter also referred to as "(meth)acrylic monomer"), the (meth)acrylic monomer may be a monofunctional (meth)acrylate containing one (meth)acryloyl group in one molecule, or a polyfunctional (meth)acrylate containing two or more (meth)acryloyl groups in one molecule.

[0088] Examples of monofunctional (meth)acrylic monomers include linear, branched, or cyclic alkyl (meth)acrylates.

[0089] From the viewpoint of liquid crystalline properties, the number of carbon atoms in the alkyl group of the alkyl (meth)acrylate is preferably in the range of 1 to 18, more preferably in the range of 3 to 15, and even more preferably in the range of 3 to 12.

[0090] Examples of the alkyl (meth)acrylates mentioned above include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, octyl (meth)acrylate, isononyl (meth)acrylate, isodecyl (meth)acrylate, t-butyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, isostearyl (meth)acrylate, cyclohexyl (meth)acrylate, 4-t-cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, and dicyclopentanyl (meth)acrylate.

[0091] There are no particular limitations on the polyfunctional (meth)acrylate, and examples include hexanediol di(meth)acrylate, butanediol di(meth)acrylate (1,3-butanediol di(meth)acrylate and 1,4-butanediol di(meth)acrylate (1,4-bis(acryloyloxy)butane)), ethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, and trimethylolpropane tri(meth)acrylate.

[0092] The monofunctional (meth)acrylic monomer may further contain a (meth)acrylate containing a functional group other than the (meth)acryloyl group. There are no particular restrictions on the functional group other than the (meth)acryloyl group, and examples include a hydroxyl group, a carboxyl group, an alkoxy group, an amide group, an amino group, and a glycidyl group.

[0093] Examples of (meth)acrylates containing a hydroxyl group include 2-hydroxyethyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, 12-hydroxylauryl (meth)acrylate, and 3-methyl-3-hydroxybutyl (meth)acrylate. Among these, from the viewpoint of excellent compatibility and rubber elasticity, the hydroxyl group-containing (meth)acrylate is preferably at least one selected from 2-hydroxyethyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and 2-hydroxypropyl (meth)acrylate, and more preferably at least one of 2-hydroxyethyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate.

[0094] Examples of (meth)acrylates containing a carboxyl group include (meth)acrylic acid and β-carboxyethyl (meth)acrylate. Among these, (meth)acrylic acid is preferred as the (meth)acrylate containing a carboxyl group from the viewpoint of excellent compatibility and rubber elasticity.

[0095] Examples of (meth)acrylates containing an alkoxy group include methoxyethyl (meth)acrylate, 2-(ethoxyethoxy)ethyl (meth)acrylate, phenoxyethyl (meth)acrylate, methoxypolypropylene glycol (meth)acrylate, polypropylene glycol (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, and methoxytriethylene glycol (meth)acrylate.

[0096] Examples of (meth)acrylates containing a glycidyl group include glycidyl acrylate.

[0097] From the viewpoint of obtaining compatibility with specific cellulose derivatives and liquid crystalline properties, the polymerizable monomer is preferably a monomer having an acryloyl group.

[0098] The polymerizable monomer may contain at least one of alkyl (meth)acrylate, hydroxyl group-containing (meth)acrylate, and carboxyl group-containing (meth)acrylate. From the viewpoint of improving the reflection characteristics of both circularly polarized light in liquid crystal films, it is preferable that the polymerizable monomer contains at least one of hydroxyl group-containing (meth)acrylate and carboxyl group-containing (meth)acrylate (hereinafter also referred to as "specific (meth)acrylate compound"). For example, when the specific cellulose derivative includes an alkyl cellulose derivative such as a hydroxypropyl cellulose derivative, using the specific (meth)acrylate compound tends to improve the reflection characteristics of left-circularly polarized light in liquid crystal films. When the specific cellulose derivative includes an alkyl cellulose derivative such as an ethyl cellulose derivative, using the specific (meth)acrylate compound tends to improve the reflection characteristics of right-circularly polarized light in liquid crystal films. The reason why the reflection properties of both circularly polarized light are improved by using certain (meth)acrylate compounds is presumed to be because hydrogen bonds formed by hydroxyl groups or carboxyl groups contained in those particular (meth)acrylate compounds affect the reflection properties. However, this disclosure is not limited to the above presumption.

[0099] When the sum of the degree of substitution of groups having unsaturated double bonds per constituent unit and the degree of substitution of acyl groups per constituent unit in a specific cellulose derivative is large, for example, 2.95 or more, 2.98 or more, or 3.00 or more, the liquid crystal material of this disclosure preferably contains at least one (meth)acrylate compound containing hydroxyl groups and a (meth)acrylate compound containing carboxyl groups. As a result, when the proportion of hydroxyl groups in the specific cellulose derivative is small, the hydrogen bonds formed by the hydroxyl groups or carboxyl groups contained in the specific (meth)acrylate compound affect the reflective properties, and the reflective properties of both circularly polarized light in the liquid crystal film tend to improve.

[0100] Polymerizable monomers containing two or more groups having unsaturated double bonds include, for example, the aforementioned polyfunctional (meth)acrylates, with 1,4-butanediol di(meth)acrylate being preferred.

[0101] Examples of polymerizable monomers having a carboxyl group in their molecule include the aforementioned (meth)acrylates having a carboxyl group, with acrylic acid being preferred.

[0102] From the viewpoint of liquid crystalline properties, the polymerizable monomer content may be 1% to 60% by mass, 2% to 50% by mass, or 3% to 40% by mass, relative to the total mass of the liquid crystal material. The polymerizable monomer content may be appropriately changed depending on the type of specific cellulose derivative (e.g., alkylcellulose derivative, hydroxyalkylcellulose derivative), the amount and type of unsaturated double bond groups or acyl groups introduced into the specific cellulose derivative (e.g., the degree of substitution of unsaturated double bond groups per constituent unit, the degree of substitution of acyl groups per constituent unit, the number of carbon atoms in the acyl group), and the type of polymerizable monomer used.

[0103] <Other ingredients> The liquid crystal material of this disclosure may contain components other than specific cellulose derivatives and polymerizable monomers (hereinafter also referred to as "other components") to the extent that the effects of this disclosure are obtained. Other components include, for example, polymerization initiators, crosslinking agents, flame retardants, compatibilizers, antioxidants, mold release agents (release agents), lightfastness agents, weathering agents, modifiers, antistatic agents, hydrolysis inhibitors, etc. As the polymerization initiator, known polymerization initiators (e.g., thermal polymerization initiators, photopolymerization initiators) can be used.

[0104] If the liquid crystal material of this disclosure contains polymerization initiators such as thermal polymerization initiators and photopolymerization initiators, the content of the polymerization initiator (preferably a photopolymerization initiator) may be 0.1% to 5% by mass, 0.2% to 3% by mass, or 0.3% to 2% by mass, based on the total mass of the liquid crystal material.

[0105] [LCD film] The liquid crystal film of this disclosure is obtained by curing the liquid crystal material of this disclosure described above and has both left-circularly polarized and right-circularly polarized reflection properties. The liquid crystal film of this disclosure may also be a liquid crystal film obtained by applying a shear force to the liquid crystal material to orient the cellulose derivative contained in the liquid crystal material, and then curing the liquid crystal material.

[0106] From the viewpoint of having good polarization characteristics, the liquid crystal film of this disclosure may be a liquid crystal film obtained by curing the liquid crystal material of this disclosure described above and including a region in which retardation is 200 nm or more. When the cellulose derivative includes a hydroxyalkylcellulose skeleton (preferably a hydroxypropylcellulose skeleton), the proportion of left-circularly polarized reflected light increases, and from the viewpoint of easily obtaining good bipolarized reflection characteristics, a liquid crystal film including a region in which retardation is 300 nm or more is preferred. In this disclosure, the retardation value is a value measured by the senarlmont method. In this disclosure, the retardation value may differ depending on the measurement region. For example, the retardation value may be 200 nm or more in regions where the applied shear force is large, and less than 200 nm in regions where the applied shear force is small.

[0107] The liquid crystal film may include a region where the retardation is between 300 nm and 1000 nm, or it may include a region where the retardation is between 400 nm and 600 nm.

[0108] The liquid crystal film of this disclosure may be a liquid crystal film having a thickness of 200 μm or more, obtained by curing the liquid crystal material of this disclosure as described above, from the viewpoint of having good polarization characteristics. The thickness of the liquid crystal film may be 300 μm to 1000 μm, or 400 μm to 800 μm. When the cellulose derivative contains a hydroxyalkylcellulose skeleton (preferably a hydroxypropylcellulose skeleton), the retardation value increases, which increases the proportion of left-circularly polarized reflected light, and from the viewpoint of easily obtaining good bipolarized reflection characteristics, the thickness of the liquid crystal film is preferably 300 μm or more, and more preferably 300 μm to 600 μm or more. Furthermore, the thickness of the liquid crystal film is not limited to the aforementioned numerical range. The retardation value can be increased by changing the manufacturing conditions of the liquid crystal film, for example, by adjusting the shear rate during the shearing process or adjusting the orientation time during the orientation process. Therefore, even when the liquid crystal film is thin, it is possible to obtain a liquid crystal film with good bipolarized reflection characteristics.

[0109] <Method for manufacturing liquid crystal film> A method for manufacturing a liquid crystal film according to the present disclosure includes a shearing step of applying a shearing force to the liquid crystal material according to the present disclosure, an orientation step of leaving the liquid crystal material after the shearing step to be oriented, and a curing step of curing the liquid crystal material after the orientation step.

[0110] The liquid crystal film manufacturing method of this disclosure makes it possible to manufacture a liquid crystal film having both left-circularly polarized and right-circularly polarized reflection characteristics by going through the above steps.

[0111] (Shearing process) The shearing process is a process of applying a shearing force to the liquid crystal material of the present disclosure as described above. When a shear force is applied to the liquid crystal material of the present disclosure described above, the cellulose derivative exhibiting a cholesteric liquid crystal orientation state with a molecular helical structure contained in the liquid crystal material orients in the shear direction. At this time, the molecular helical structure tilts in the shear direction. Furthermore, the molecules orient in the shear direction increases birefringence.

[0112] The method for applying shear force to a liquid crystal material is not particularly limited as long as the molecular helical structure can be tilted in the shear direction. For example, a shear strain in a certain direction may be applied to the liquid crystal material using a rheometer or the like. When using a rheometer, the liquid crystal material is attached to the lower jig, and the liquid crystal material is sandwiched between the upper jig, such as a parallel plate or cone plate, and the lower jig, and a shear strain in a certain direction is applied to the liquid crystal material.

[0113] The temperature during the shearing process is not particularly limited and may be room temperature (around 25°C), and the shearing process and the processes described later may be performed while heating.

[0114] The shear rate when applying shear force to the liquid crystal material is not particularly limited and may be adjusted as appropriate depending on the type of cellulose derivative (e.g., the degree of hydroxyl group substitution in the cellulose derivative), the type of polymerizable monomer (e.g., the presence or absence of hydroxyl groups and carboxyl groups), etc.

[0115] (Orientation process) The orientation process is a process in which the liquid crystal material is left to stand after the shearing process to allow it to orient itself. This allows for the reorientation of cholesteric liquid crystals that have been disrupted by shearing, resulting in vivid reflective colors.

[0116] The waiting time for the liquid crystal material after the shearing process is not particularly limited and may be adjusted as appropriate depending on the magnitude of the shear strain, the type of cellulose derivative (e.g., the degree of hydroxyl group substitution in the cellulose derivative), the type of polymerizable monomer (e.g., the presence or absence of hydroxyl and carboxyl groups), etc. Furthermore, increasing the waiting time tends to restore the tilt of the molecular helical structure. Therefore, by adjusting the waiting time, the tilt of the molecular helical structure can be adjusted, and the reflection wavelength of the liquid crystal film can also be adjusted.

[0117] The waiting time may be, for example, 10 seconds to 5 hours, 100 seconds to 1 hour, or 200 seconds to 30 minutes.

[0118] (hardening process) The curing process is the process of curing the liquid crystal material after the orientation process. By curing the liquid crystal material after the orientation process, specific cellulose derivatives, polymerizable monomers, etc., undergo a crosslinking reaction, resulting in a crosslinked structure where the molecular helical structure is tilted and birefringence is increased. As a result, the tilted molecular helical structure is fixed, and a liquid crystal film with increased birefringence is obtained.

[0119] Curing methods include curing the liquid crystal material by heat treatment and curing the liquid crystal material by irradiating it with light such as ultraviolet light. When curing by heat treatment, the liquid crystal material preferably contains a thermal polymerization initiator, and when curing by light irradiation, the liquid crystal material preferably contains a photopolymerization initiator.

[0120] The heat treatment method is not particularly limited, and may, for example, be a heat treatment method using a known heating device. There are no particular restrictions on the heating device; examples include ovens, infrared heaters, and hot plates.

[0121] The heat treatment temperature is preferably 25°C to 130°C, more preferably 25°C to 120°C, and even more preferably 25°C to 110°C. The heat treatment temperature is controlled so that the liquid crystal material falls within the above range.

[0122] The heat treatment process allows for the fixing of orientation at the Bragg reflection wavelength by controlling heat treatment conditions such as temperature and heating time.

[0123] The temperature at which the liquid crystal material is irradiated with light such as ultraviolet light (hereinafter also referred to as the "UV irradiation temperature") is preferably 0°C to 100°C, more preferably 5°C to 50°C, and even more preferably 10°C to 40°C. The UV irradiation temperature is controlled so that the liquid crystal material is within the above range.

[0124] Furthermore, the irradiation intensity of light such as ultraviolet light is preferably 1 mW / cm². 2 More than 200mW / cm 2 More preferably 5 mW / cm² 2 More than 150mW / cm 2 More preferably, 10 mW / cm² 2 More than 100mW / cm 2 The following applies:

[0125] The irradiation time for ultraviolet light or similar light is preferably 5 seconds to 40 minutes, and more preferably 2 minutes to 20 minutes.

[0126] The presence or absence of left-circular polarization or right-circular polarization in a liquid crystal film is indistinguishable to the naked eye. Therefore, by patterning letters, figures, etc., using the reflected color from left-circular polarization or right-circular polarization, applications in anti-counterfeiting technology can be expected. [Examples]

[0127] The present invention will be described below with reference to examples, but the present invention is not limited to these examples. In the following description, unless otherwise specified, all "%"s are based on mass.

[0128] (Example 1) [Synthesis of HPC derivative 1] HPC derivative 1 was synthesized according to the following scheme. Add 30 mL of dehydrated acetone to a 200 mL round-bottom flask filled with nitrogen, then add 6.00 g (15.2 mmol) of hydroxypropyl cellulose (HPC) (Mw=4.5 × 10⁻¹⁴). 4 Weighed out the PDI (1.9) and dissolved it in dehydrated acetone while stirring to obtain the HPC solution.

[0129] The HPC solution was shielded from light with aluminum foil, and 1.29 g of Karenz AOI (2-isocyanatoethyl acrylate, manufactured by Showa Denko K.K., registered trademark) (0.2 equivalents relative to the hydroxyl groups) was added at room temperature. The mixture was reacted at room temperature and shielded from light for 24 hours, after which 6.33 g of propionyl chloride (1.5 equivalents relative to the hydroxyl groups) was added and the mixture was reacted for a further 22 hours. After the reaction was complete, the reaction solution was added dropwise to ultrapure water to precipitate the product. This product was washed with ultrapure water and dried, then dissolved in a small amount of acetone, and then added dropwise to ultrapure water to reprecipitation. After this redissolution and reprecipitation washing procedure, dialysis was performed twice using 1 L of acetone. Next, this product was added dropwise to ultrapure water to precipitate, and then dried under reduced pressure to obtain HPC derivative 1 (hereinafter also referred to as "HPC-AcC / PrE").

[0130] [ka]

[0131] ( 1 (Measurement of H-NMR spectrum) The HPC derivative 1 synthesized above 1 The 1H-NMR spectrum was measured. The peaks originating from HPC derivative 1 in this embodiment (specifically, peaks originating from HPC-AcC / PrE) are as follows: the peaks around 5.8 ppm, 6.1 ppm, and 6.4 ppm are proton peaks attached to the double bond of the acryloyl group, respectively; the peak around 4.7 ppm to 5.2 ppm is the methine group of the terminal hydroxypropyl group; and the peak around 2.7 ppm to 4.5 ppm are protons in the β-glucose monomer unit and protons of the methine group on the hydroxypropyl group of the side chain (proton peaks originating from the HPC skeleton).

[0132] The peak around 2.3 ppm is attributed to the proton of the methylene group of the propionyl group adjacent to the carboxyl group. The peaks around 1.0 ppm to 1.3 ppm were assigned to the proton peaks of the terminal methyl group of the hydroxypropyl group and the methyl group of the propionyl group.

[0133] In other words, the peaks in the 4.7 ppm to 5.2 ppm range may represent protons from the methine group when the terminal hydroxypropyl group is carbamate or esterified, or from protons from the methine group when the 2nd or 3rd position of the β-glucose monomer unit is carbamate or esterified.

[0134] From the above results, HPC derivative 1 was an "HPC acryloylethyl carbamate / propionyl mixed ester" in which the hydrogen atoms of the hydroxyl group, which is the side chain of HPC, were substituted with CH2=CH-C(=O)-O-(CH2)2-NHC(=O)-(acryloylethyl carbamate group) and a propionyl group.

[0135] Based on the assigned peaks, the degree of substitution of the HPC side chain (hydrogen atom in the hydroxyl group) to a group with an unsaturated double bond (i.e., acryloylethyl carbamate group) and to an acyl group (i.e., propionyl group) was calculated. HPC derivative 1 had a degree of substitution of 0.23 to the acryloylethyl carbamate group (a group with an unsaturated double bond) and a degree of substitution of 2.62 to the propionyl group (acyl group) (HPC-AcC / PrE(AcC:PrE=0.23:2.62)).

[0136] <Fabrication of liquid crystal material 1> Liquid crystal material 1 was prepared using HPC derivative 1 obtained as described above, butyl acrylate (BA) (manufactured by Tokyo Chemical Industry Co., Ltd., A0142, glass transition temperature (Tg): -40°C), and 2-hydroxy-2-methylpropiophenone (HMPP) as a photopolymerization initiator. Specifically, HPC derivative 1, BA, and HMPP were thoroughly mixed in a mass ratio of 87.9:11.5:0.6, and then degassed under vacuum for a short time to prepare liquid crystal material 1.

[0137] <Fabrication of liquid crystal film 1> In a rheometer, the liquid crystal material 1 prepared as described above was subjected to shear orientation treatment, and then, after the shear orientation treatment, the liquid crystal material 1 was left to stand for a certain period of time before being irradiated with light to produce a liquid crystal film 1. Specifically, a rheometer was prepared that had a 25 mm diameter parallel plate as an upper jig and a glass plate equipped with a Peltier element as a lower jig, and that could irradiate ultraviolet light from the lower jig side. Release sheets were attached to the upper and lower jigs. The liquid crystal material 1 was placed on a glass plate adjusted to 25°C, and the liquid crystal material 1 was sandwiched between the parallel plate and the glass plate. At this time, the gap d between the parallel plate and the glass plate was set to 500 μm. The liquid crystal material 1 sandwiched between the parallel plate and the glass plate was subjected to a shear rate of 0.2 s. -1 or 0.5s -1 A shear orientation treatment was performed for 300 seconds under the specified conditions. The shear rate increased proportionally to the distance from the center in a plan view, and in this experiment, the shear rate at the position furthest from the center (i.e., distance r: 12.5 mm from the center) was adjusted to the above value. To obtain a liquid crystal film exhibiting vivid reflective colors by reorienting the disordered liquid crystal structure, the liquid crystal material 1 after the shear orientation treatment was left to stand for 200 seconds. After the standing period, an LED light source was used on the liquid crystal material 1 with a wavelength of 365 nm and an intensity of 80 mW / cm². 2 The liquid crystal material 1 was irradiated with ultraviolet light for 6 minutes. Through this process, the liquid crystal material 1 was cured to obtain the liquid crystal film 1.

[0138] <Measurement of circularly polarized transmission spectrum> The circularly polarized transmission spectrum was measured using the liquid crystal film 1 (thickness of liquid crystal film 1: approximately 500 μm) obtained in Example 1. For the measurement of the circularly polarized transmission spectrum, an optical measurement system comprising a white light source, a linear polarizer, a quarter-wave plate, an achromatic focusing lens, and a spectrometer was used. A glass plate containing the liquid crystal film 1 was placed between the quarter-wave plate and the achromatic focusing lens. Light was shone from the white light source onto the liquid crystal film 1, and the transmitted light was received by the spectrometer. The measurement results of the circularly polarized transmission spectrum are shown in Figures 1 and 2. Figure 1(a) shows the result at a shear rate of 0.2 s. -1This is a diagram showing the change in the transmission spectrum of left circularly polarized light when the liquid crystal film 1 is fabricated under the condition of -1 This is a diagram showing the change in the transmission spectrum of right circularly polarized light when the liquid crystal film 1 is fabricated under the condition of -1 This is a diagram showing the change in the transmission spectrum of left circularly polarized light when the liquid crystal film 1 is fabricated under the condition of -1 This is a diagram showing the change in the transmission spectrum of right circularly polarized light when the liquid crystal film 1 is fabricated under the condition of. In FIGS. 1 and 2, r means the distance from the center of the liquid crystal film in plan view (the same applies hereinafter to FIG. 3 and later).

[0139] As shown in FIGS. 1 and 2, it was confirmed that the liquid crystal film 1 reflects right circularly polarized light and left circularly polarized light. Under the condition of a shear rate of 0.2 s -1 and under the condition of a shear rate of 0.5 s -1 the reflection wavelengths of the liquid crystal film 1 under these conditions varied depending on the right circularly polarized light or left circularly polarized light and the measurement position of the liquid crystal film, and were within the range of 570 nm to 630 nm. The reflection wavelength of the liquid crystal film 1 in the state where the shear alignment treatment was not performed was 642 nm.

[0140] (Example 2) <Fabrication of Liquid Crystal Material 2> Using the HPC derivative 1, 4-hydroxybutyl acrylate (manufactured by Tokyo Chemical Industry Co., Ltd., product code; A1390, 4HBA, glass transition temperature (Tg); -32 ° C) and HMPP obtained as described above, liquid crystal materials 2 and 3 were fabricated. Specifically, after thoroughly mixing the HPC derivative 1, 4HBA and HMPP so that the mass ratio was 90.8:8.5:0.7, they were vacuum degassed for a short time to fabricate the liquid crystal material 2. Further, after thoroughly mixing the HPC derivative 1, 4HBA and HMPP so that the mass ratio was 91.0:8.4:0.6, they were vacuum degassed for a short time to fabricate the liquid crystal material 3.

[0141] <Fabrication of Liquid Crystal Films 2 to 4> Using the liquid crystal material 2 instead of the liquid crystal material 1, with a shear rate of 0.2 s -1Liquid crystal film 2 was manufactured in the same manner as liquid crystal film 1, except that a shear orientation treatment was performed under the specified conditions, and the liquid crystal material 2 after the shear orientation treatment was allowed to wait for 300 seconds. Liquid crystal material 3 was used instead of liquid crystal material 1, with a shear rate of 0.5 s. -1 Liquid crystal film 3 was manufactured in the same manner as liquid crystal film 1, except that a shear orientation treatment was performed under the specified conditions, and the liquid crystal material 2 after the shear orientation treatment was left to stand for 300 seconds. Liquid crystal film 4 was manufactured in the same manner as liquid crystal film 2, except that liquid crystal material 2 was used and the liquid crystal material 2 was allowed to wait for 200 seconds after shear orientation treatment.

[0142] <Measurement of circularly polarized transmission spectrum> Using the liquid crystal film 2 (thickness of liquid crystal film 2: approximately 500 μm), liquid crystal film 3 (thickness of liquid crystal film 3: approximately 500 μm), and liquid crystal film 4 (thickness of liquid crystal film 4: approximately 500 μm) obtained in Example 2, the circularly polarized transmission spectra were measured in the same manner as for liquid crystal film 1. The measurement results of the circularly polarized transmission spectra are shown in Figures 3 to 5.

[0143] As shown in Figures 3 to 5, it was confirmed that liquid crystal films 2 to 4 reflected both right-circularly polarized and left-circularly polarized light. In liquid crystal film 3, green reflected light was observed around r=0mm and 3mm, and it was confirmed that right-circularly polarized and left-circularly polarized light were well reflected in the region where shear is small and r is 5mm or less. Comparing liquid crystal film 2 and liquid crystal film 4, it was confirmed that increasing the orientation time made the reflected light of right-circularly polarized and left-circularly polarized light clearer. The reflected wavelengths of liquid crystal films 2 to 4 varied depending on whether the light was right-circularly polarized or left-circularly polarized, and the measurement position of the liquid crystal film, and were within the range of 500nm to 560nm. In the state without shear orientation treatment, the reflected wavelength of liquid crystal film 2 was 572nm, the reflected wavelength of liquid crystal film 3 was 586nm, and the reflected wavelength of liquid crystal film 4 was 572nm.

[0144] (Example 3) [Synthesis of HPC derivative 2] HPC derivative 2 was synthesized according to the following scheme. 30 mL of dehydrated acetone was added to a 200 mL eggplant flask filled with nitrogen, and then 6.00 g (15.2 mmol) of hydroxypropyl cellulose (HPC) (Mw = 4.5×10 4 , PDI = 1.9) was weighed and dissolved in dehydrated acetone with stirring to obtain an HPC solution.

[0145] The HPC solution was shielded from light with aluminum foil, 0.97 g of Karenz AOI (2-isocyanatoethyl acrylate, manufactured by Showa Denko K.K., registered trademark) (0.15 equivalent to the hydroxyl group) was added at room temperature, and after reacting for 24 hours at room temperature in the dark, 14.6 g of butyryl chloride (3.0 equivalents to the hydroxyl group) was added and the reaction was continued for another 22 hours. After completion of the reaction, HPC derivative 2 (hereinafter also referred to as "HPC-AcC / BuE") was obtained by performing the same operations as those in obtaining HPC derivative 1 in Example 1.

[0146] [Chemical formula]

[0147] 1 The 1H-NMR spectrum was measured, and based on the assigned peaks, the substitution degree to the group having an unsaturated double bond (i.e., acryloyl group) and the substitution degree to the acyl group (i.e., butyryl group) in the HPC side chain (hydrogen atom in the hydroxyl group) were calculated. For HPC derivative 2, the substitution degree to the acryloyl group (group having an unsaturated double bond) was 0.05, and the substitution degree to the butyryl group (acyl group) was 2.83 (HPC-AcC / BuE (AcC:BuE = 0.05:2.83)).

[0148] [Preparation of liquid crystal material 4] Liquid crystal material 4 was prepared using the HPC derivatives 2,4-hydroxybutyl acrylate (4HBA) and HMPP obtained as described above. Specifically, the HPC derivatives 2,4HBA and HMPP were thoroughly mixed in a mass ratio of 90.5:8.6:0.9, and then degassed under vacuum for a short time to prepare liquid crystal material 4.

[0149] <Fabrication of liquid crystal film 5> Liquid crystal material 4 was used instead of liquid crystal material 1, with a shear rate of 1.0 s. -1 A liquid crystal film 5 was manufactured in the same manner as the liquid crystal film 1, except that a shear orientation treatment was performed under the specified conditions, and the liquid crystal material 4 after the shear orientation treatment was allowed to wait for 60 seconds.

[0150] <Measurement of circularly polarized transmission spectrum> Using the liquid crystal film 5 obtained in Example 3 (thickness of liquid crystal film 5: approximately 500 μm), the circularly polarized transmission spectrum was measured in the same manner as with liquid crystal film 1. The measurement results of the circularly polarized transmission spectrum are shown in Figure 6.

[0151] As shown in Figure 6, it was confirmed that the liquid crystal film 5 reflects both right-circularly polarized and left-circularly polarized light. The reflection wavelength of the liquid crystal film 5 varied depending on whether the light was right-circularly polarized or left-circularly polarized, and the measurement position on the liquid crystal film, and was within the range of 550 nm to 600 nm. The reflection wavelength of the liquid crystal film 5 without shear orientation treatment was 627 nm.

[0152] (Example 4) [Synthesis of HPC derivative 3] HPC derivative 3 (hereinafter also referred to as "HPC-AcC / BuE") was synthesized in the same manner as HPC derivative 2, except that the amount of Karenz AOI used was changed to 0.64 g (0.1 equivalent relative to the hydroxyl groups) and the amount of butyryl chloride used was changed to 15.0 g (3 equivalents relative to the hydroxyl groups).

[0153] 1¹H-NMR spectra were measured, and based on the assigned peaks, the degree of substitution of the HPC side chain (hydrogen atom in the hydroxyl group) to a group with an unsaturated double bond (i.e., an acryloyl group) and to an acyl group (i.e., a butyryl group) was calculated. HPC derivative 3 had a degree of substitution of 0.04 for the acryloyl group (a group with an unsaturated double bond) and a degree of substitution of 2.97 for the butyryl group (acyl group) (HPC-AcC / BuE (AcC:BuE=0.04:2.97)). The fact that the sum of the groups with unsaturated double bonds and acyl groups exceeds 3.00 indicates that almost all hydroxyl groups in HPC are... hydrogen atom This means that it is substituted with a group having an unsaturated double bond or an acyl group.

[0154] (Example 5) [Synthesis of HPC derivative 4] HPC derivative 4 (hereinafter also referred to as "HPC-AcC / BuE") was synthesized in the same manner as the synthesis of HPC derivative 2, except that the amount of Karenz AOI used was changed to 0.97 g (0.15 equivalents relative to the hydroxyl groups) and the amount of butyryl chloride used was changed to 15.0 g (3 equivalents relative to the hydroxyl groups).

[0155] 1 ¹H-NMR spectra were measured, and based on the assigned peaks, the degree of substitution of the HPC side chain (hydrogen atom in the hydroxyl group) to a group with an unsaturated double bond (i.e., an acryloyl group) and to an acyl group (i.e., a butyryl group) was calculated. HPC derivative 3 had a degree of substitution of 0.09 to the acryloyl group (a group with an unsaturated double bond) and a degree of substitution of 2.92 to the butyryl group (acyl group) (HPC-AcC / BuE (AcC:BuE=0.09:2.92)).

[0156] <Fabrication of liquid crystal materials 5 and 6> Liquid crystal material 5 was prepared using the HPC derivatives 3,4-hydroxybutyl acrylate (4HBA) and HMPP obtained as described above. Specifically, HPC derivatives 3,4HBA and HMPP were thoroughly mixed in a mass ratio of 89.3:10.4:0.2, and then degassed under vacuum for a short time to prepare liquid crystal material 5. Furthermore, the HPC derivative 4 obtained as described above, acrylic acid, and HMPP were thoroughly mixed, and then degassed under vacuum for a short time to prepare the liquid crystal material 6.

[0157] <Fabrication of liquid crystal films 6 and 7> Liquid crystal materials 5 and 6 were used instead of liquid crystal material 1, with a shear rate of 1.0 s. -1 Liquid crystal films 6 and 7 were manufactured in the same manner as liquid crystal film 1, except that a shear orientation treatment was performed under the specified conditions, and the liquid crystal materials 5 and 6 were allowed to wait for 60 seconds after the shear orientation treatment.

[0158] <Measurement of circularly polarized transmission spectrum> The circularly polarized transmission spectra were measured in the same manner as for liquid crystal film 1 using liquid crystal film 6 obtained in Example 4 (thickness of liquid crystal film 6: approximately 500 μm) and liquid crystal film 7 obtained in Example 5 (thickness of liquid crystal film 6: approximately 500 μm). The measurement results of the circularly polarized transmission spectra are shown in Figures 7 and 8.

[0159] As shown in Figures 7 and 8, it was confirmed that liquid crystal films 6 and 7 reflected both right-circularly polarized and left-circularly polarized light. The reflection wavelength of liquid crystal film 7 was approximately 570 nm for both right-circularly polarized and left-circularly polarized light. The reflection wavelength of liquid crystal film 7 without shear orientation treatment was 597 nm.

[0160] (Example 6) [Synthesis of HPC derivative 5] HPC derivative 5 was synthesized according to the following scheme. Add 30 mL of dehydrated acetone to a 200 mL round-bottom flask filled with nitrogen, then add 6.00 g (15.2 mmol) of hydroxypropyl cellulose (HPC) (Mw=4.5 × 10⁻¹⁴).4 Weighed out the PDI (1.9) and dissolved it in dehydrated acetone while stirring to obtain the HPC solution.

[0161] The HPC solution was shielded from light with aluminum foil, and 1.29 g of Karenz AOI (2-isocyanatoethyl acrylate, manufactured by Showa Denko K.K., registered trademark) (0.2 equivalents relative to the hydroxyl groups) was added at room temperature and in the dark. After that, 4.66 g of acetyl chloride (1.3 equivalents relative to the hydroxyl groups) was added and the reaction was continued for a further 22 hours. After the reaction was complete, HPC derivative 5 (hereinafter also referred to as "HPC-AcC / EtE") was obtained by performing the same procedure as in Example 1 to obtain HPC derivative 1.

[0162] [ka]

[0163] 1 By measuring the 1H-NMR spectrum and based on the assigned peaks, the degree of substitution of the HPC side chain (hydrogen atom in the hydroxyl group) to a group with an unsaturated double bond (i.e., an acryloyl group) and to an acyl group (i.e., an acetyl group) was calculated. HPC derivative 5 had a degree of substitution of 0.02 to the acryloyl group (a group with an unsaturated double bond) and a degree of substitution of 2.92 to the acetyl group (acyl group) (HPC-AcC / EtE (AcC:EtE=0.02:2.90)).

[0164] <Fabrication of liquid crystal material 7> A liquid crystal material 7 was prepared using the HPC derivative 5, butyl acrylate (BA), and HMPP obtained as described above. Specifically, the HPC derivative 5, BA, and HMPP were thoroughly mixed in a mass ratio of 72.7:26.4:0.8, and then degassed under vacuum for a short time to prepare the liquid crystal material 7.

[0165] <Fabrication of LCD film 8> Liquid crystal material 7 was used instead of liquid crystal material 1, with a shear rate of 0.5 s. -1The liquid crystal film 8 was produced in the same manner as the liquid crystal film 1, except that the shear orientation treatment was performed under the conditions of , and the liquid crystal material 7 after the shear orientation treatment was allowed to stand for 200 seconds.

[0166] <Measurement of circular polarization transmission spectrum> Using the liquid crystal film 8 obtained in Example 6 (thickness of the liquid crystal film 8: 560 μm), the circular polarization transmission spectrum was measured in the same manner as the liquid crystal film 1. The measurement results of the circular polarization transmission spectrum are shown in FIG. 9.

[0167] As shown in FIG. 9, it was confirmed that the liquid crystal film 8 reflected right circular polarization and left circular polarization. When compared with FIGS. 2 and 6, the liquid crystal film 8 produced using the HPC derivative 5 (HPC-AcC / EtE) had better reflection characteristics than the liquid crystal film 1 produced using the HPC derivative 1 (HPC-AcC / PrE) and the liquid crystal film 5 produced using the HPC derivative 2 (HPC-AcC / BuE).

[0168] <Production of liquid crystal film 9> In order to confirm the influence of the thickness of the liquid crystal film on the reflection characteristics of right circular polarization and left circular polarization, a liquid crystal film 9 with a different thickness from the liquid crystal film 8 was produced using the liquid crystal material 7 with good reflection characteristics. Specifically, the liquid crystal film 9 was produced in the same manner as the liquid crystal film 8, except that the gap d between the parallel plate and the glass plate was changed from 500 μm to 150 μm.

[0169] <Measurement of circular polarization transmission spectrum> Using the liquid crystal film 9 (thickness of the liquid crystal film 9: 178 μm), the circular polarization transmission spectrum was measured in the same manner as the liquid crystal film 1. The measurement results of the circular polarization transmission spectrum are shown in FIG. 10.

[0170] As shown in FIG. 10, in the liquid crystal film 9, the reflection of right circular polarization was clearly confirmed, but the reflection of left circular polarization was hardly confirmed. From the results of FIGS. 9 and 10, it was confirmed that the reflection characteristics of right circular polarization and left circular polarization changed by changing the thickness of the liquid crystal film.

[0171] The reason why the reflection of left-circularly polarized light becomes difficult to observe when the liquid crystal film is thin is presumed to be a decrease in retardation. Figure 11 shows the relationship between the distance from the center in a planar view and the birefringence for liquid crystal film 8 and liquid crystal film 9. Figure 12 shows the relationship between the distance from the center in a planar view and the retardation for liquid crystal film 8 and liquid crystal film 9. The retardation of liquid crystal film 8 and liquid crystal film 9 was measured using the Senarmont method with a quarter-wave plate and a linear polarizer, and the birefringence of liquid crystal film 8 and liquid crystal film 9 was determined by dividing the measured retardation value by the thickness of liquid crystal film 8 and liquid crystal film 9.

[0172] As shown in Figure 11, there was no significant difference in the birefringence of liquid crystal film 8 and liquid crystal film 9, and both tended to increase in value as the distance from the center increased. Since shear orientation treatment was performed using a parallel plate, the shear rate also increased as the distance from the center increased, and as a result, it was confirmed that the birefringence also increased. As shown in Figure 12, there was a significant difference in the retardation of liquid crystal film 8 and liquid crystal film 9, with liquid crystal film 8 tending to have a greater retardation than liquid crystal film 9.

[0173] From the birefringence results, it can be inferred that the degree of orientation of the liquid crystal due to the shear orientation treatment does not change significantly between liquid crystal film 8 and liquid crystal film 9. On the other hand, from the retardation results, it can be inferred that the ability of some of the reflected right-circularly polarized light to be converted to left-circularly polarized light decreases as the thickness decreases, making it more difficult to observe the reflection of left-circularly polarized light.

[0174] (Example 7) [Synthesis of HPC derivative 6] HPC derivative 6 (hereinafter also referred to as "HPC-AcC / EtE") was synthesized in the same manner as the synthesis of HPC derivative 5, except that the amount of Karenz AOI used was changed to 1.29 g (0.2 equivalents relative to the hydroxyl groups) and the amount of acetyl chloride used was changed to 4.65 g (1.3 equivalents relative to the hydroxyl groups).

[0175] 1 By measuring the 1H-NMR spectrum and based on the assigned peaks, the degree of substitution of the HPC side chain (hydrogen atom in the hydroxyl group) to a group with an unsaturated double bond (i.e., an acryloyl group) and to an acyl group (i.e., an acetyl group) was calculated. HPC derivative 6 had a degree of substitution of 0.03 to the acryloyl group (a group with an unsaturated double bond) and a degree of substitution of 2.87 to the acetyl group (acyl group) (HPC-AcC / EtE (AcC:EtE=0.03:2.87)).

[0176] <Fabrication of liquid crystal material 8> A liquid crystal material 8 was prepared using the HPC derivative 6, butyl acrylate (BA), and HMPP obtained as described above. Specifically, the HPC derivative 6, BA, and HMPP were thoroughly mixed in a mass ratio of 77.9:21.4:0.5, and then degassed under vacuum for a short time to prepare the liquid crystal material 8.

[0177] <Manufacturing of LCD film 10> Liquid crystal material 8 was used instead of liquid crystal material 1, with a shear rate of 0.5 s. -1 A liquid crystal film 10 was manufactured in the same manner as liquid crystal film 1, except that a shear orientation treatment was performed under the specified conditions, and the waiting time of the liquid crystal material 8 after the shear orientation treatment was varied depending on the location by using a photomask. By placing a photomask between the glass plate and the release sheet on the lower jig side, ultraviolet light was irradiated only near the center of the liquid crystal material 8. For the waiting time, the waiting time after the shear orientation treatment was set to 30 seconds, and after 30 seconds, an LED light source was used with a wavelength of 365 nm and an intensity of 10 mW / cm². 2 Ultraviolet light was irradiated onto the central area of ​​the liquid crystal material 8 for 30 seconds. After UV irradiation, the photomask was removed, and a waiting period of 3 hours was allowed. After 3 hours, an LED light source with a wavelength of 365 nm and an intensity of 80 mW / cm² was used. 2 The entire surface of the liquid crystal material 8 was irradiated with ultraviolet light for 6 minutes.

[0178] (Example 8) [Synthesis of HPC derivative 7] HPC derivative 7 (hereinafter also referred to as "HPC-AcC / PrE") was synthesized in the same manner as the synthesis of HPC derivative 1, except that the amount of Karenz AOI used was changed to 1.29 g (0.2 equivalents relative to the hydroxyl groups) and the amount of propionyl chloride used was changed to 5.98 g (1.5 equivalents relative to the hydroxyl groups).

[0179] 1 ¹H-NMR spectra were measured, and based on the assigned peaks, the degree of substitution of the HPC side chain (hydrogen atom in the hydroxyl group) to a group with an unsaturated double bond (i.e., an acryloyl group) and to an acyl group (i.e., a propionyl group) was calculated. HPC derivative 3 had a degree of substitution of 0.16 for the acryloyl group (a group with an unsaturated double bond) and a degree of substitution of 2.75 for the propionyl group (acyl group) (HPC-AcC / PrE(AcC:PrE=0.16:2.75)).

[0180] <Fabrication of liquid crystal material 9> A liquid crystal material 9 was prepared using the HPC derivative 7, butyl acrylate (BA), and HMPP obtained as described above. Specifically, the HPC derivative 7, BA, and HMPP were thoroughly mixed in a mass ratio of 87.5:11.7:0.9, and then degassed under vacuum for a short time to prepare the liquid crystal material 9.

[0181] <Fabrication of liquid crystal film 11> Liquid crystal material 9 was used instead of liquid crystal material 8, with a shear rate of 8.0 s. -1 A liquid crystal film 11 was manufactured in the same manner as the liquid crystal film 10, except that a shear orientation treatment was performed under the specified conditions, and the waiting time for the liquid crystal material 9 after the shear orientation treatment was changed. By placing a photomask between the glass plate and the release sheet on the lower jig side, ultraviolet light was irradiated only near the center of the liquid crystal material 9. For the waiting time, the waiting time after the shear orientation treatment was set to 30 seconds, and after 30 seconds, an LED light source was used with a wavelength of 365 nm and an intensity of 10 mW / cm². 2Ultraviolet light was irradiated near the center of the liquid crystal material 9 for 30 seconds. After the ultraviolet irradiation, the photomask was removed, and then the waiting time was set to 10 minutes. After 10 minutes elapsed, ultraviolet light with a wavelength of 365 nm and an intensity of 80 mW / cm 2 was irradiated over the entire liquid crystal material 9 for 6 minutes.

[0182] The fabricated liquid crystal films 10 and 11 were irradiated with white light, and the reflected light of left circular polarization was confirmed. The reflection wavelength of the liquid crystal film 10 was about 500 nm for both right circular polarization and left circular polarization, and there was no significant difference depending on the measurement location. The reflection wavelength of the liquid crystal film 11 was 525 nm near the center where the waiting time was 30 seconds and 630 nm on the outside where the waiting time was 10 minutes for both right circular polarization and left circular polarization. Note that in the state where the shear alignment treatment was not performed, the reflection wavelength of the liquid crystal film 10 was 502 nm, and the reflection wavelength of the liquid crystal film 11 was 626 nm. For the vicinity of the center of the liquid crystal film 10 and the vicinity of the center of the liquid crystal film 11, reflected light with a shorter wavelength was confirmed respectively than the portions other than the vicinity of the center. Since a short wavelength shift was confirmed due to the more inclined helical axis of the liquid crystal, it is presumed that the inclination of the helical axis recovers with the passage of the waiting time. On the other hand, for each of the liquid crystal film 10 and the liquid crystal film 11, the reflected light of left circular polarization was confirmed at the vicinity of the center and the portions other than the vicinity of the center. The reflection of left circular polarization is due to an increase in birefringence, and it is presumed that the increase in birefringence is likely to be maintained even after the passage of the waiting time.

[0183] (Example 9) [Synthesis of HPC derivative 8] HPC derivative 8 (hereinafter, also referred to as "HPC-AcC / EtE") was synthesized in the same manner as the synthesis of HPC derivative 5 except that the usage amount of Calens AOI was changed to 3.87 g (0.6 equivalent to the hydroxyl group) and the usage amount of acetyl chloride was changed to 14.3 g (4.0 equivalent to the hydroxyl group).

[0184] 1By measuring the 1H-NMR spectrum and based on the assigned peaks, the degree of substitution of the HPC side chain (hydrogen atom in the hydroxyl group) to a group with an unsaturated double bond (i.e., an acryloyl group) and to an acyl group (i.e., an acetyl group) was calculated. HPC derivative 8 had a degree of substitution of 0.14 to the acryloyl group (a group with an unsaturated double bond) and a degree of substitution of 2.71 to the acetyl group (acyl group) (HPC-AcC / EtE (AcC:EtE=0.14:2.71)).

[0185] <Fabrication of liquid crystal material 10> Using the HPC derivative 8, butyl acrylate (BA), and HMPP obtained as described above, a liquid crystal material 10 with an HPC derivative concentration of 77% by mass was prepared.

[0186] <Preparation of liquid crystal film 12> Similar to Example 1, the liquid crystal material 10 prepared as described above was subjected to shear orientation treatment in a rheometer, and then the liquid crystal material 10 after shear orientation treatment was left to stand for a certain period of time before being irradiated with light to produce a liquid crystal film 12. The conditions for producing the liquid crystal film 12 were a gap d between the parallel plate and the glass plate of 100 μm to 800 μm, and a shear rate of 0.5 s. -1 The shearing time was set to 300 seconds, the waiting time to 200 seconds, and the UV irradiation conditions were set to a wavelength of 365 nm and an intensity of 80 mW / cm². 2 The irradiation time was set to 6 minutes. The liquid crystal material 10 was cured to obtain a liquid crystal film 12. Table 1 shows the relationship between the gap d and the thickness of the obtained liquid crystal film 12. Liquid crystal films 12 of different thicknesses were designated as liquid crystal films 12-1 to 12-6.

[0187] [Table 1]

[0188] <Measurement of circularly polarized transmission spectrum> Using the liquid crystal films 12-1 to 12-6 obtained in Example 9, the circularly polarized transmission spectra were measured in the same manner as in Example 1. The measurement results of the circularly polarized transmission spectra are shown in Figure 13. Figures 13(a) to 13(f) show the changes in the right-circularly polarized and left-circularly polarized spectra of liquid crystal films 12-6 to 12-1 at r=3 mm or r=9 mm, respectively.

[0189] When the circularly polarized transmission spectra of liquid crystal films 12-1 to 12-6 were measured, the reflection wavelength was approximately 400 nm. The peak intensity decreased as the thickness of the liquid crystal film decreased, and this decrease in peak intensity was particularly pronounced in left-hand circularly polarized light.

[0190] Next, the retardation of liquid crystal films 12-1 to 12-6 was measured in the same manner as in Example 6, and the birefringence of liquid crystal films 12-1 to 12-6 was determined by dividing the measured retardation value by the thickness of liquid crystal films 12-1 to 12-6. Figure 14 shows the relationship between the distance from the center in a planar view and the retardation for liquid crystal films 12-1 to 12-6. Figure 15 shows the relationship between the distance from the center in a planar view and the birefringence for liquid crystal films 12-1 to 12-6.

[0191] To investigate the relationship between the retardation values ​​of liquid crystal films 12-1 to 12-6 and the peak intensities of left-right circularly polarized light, the ratio of the peak intensities of left-right circularly polarized light was plotted against the retardation value (retardation value at r=1 to 10). The plot results are shown in Figure 16. The ratio of the peak intensities of left-right circularly polarized light is (I L -I R ) / (I L +I R ) is represented by I L This is the peak intensity of the left circularly polarized transmission spectrum, and I R is the peak intensity of the right-circularly polarized transmission spectrum, which is the value obtained by subtracting the peak top transmittance from the baseline transmittance. Here, the transmittance at a wavelength of 680 nm was used as the baseline transmittance.

[0192] As shown in Figure 16, the proportion of reflected left-circularly polarized light gradually increased as the retardation value increased from 200 nm. From around 300 nm, the ratio of peak intensities remained almost unchanged even as the retardation value increased, and the intensities of reflected left-circularly polarized and right-circularly polarized light were approximately the same. From these results, it can be inferred that to produce a liquid crystal film that reflects both left- and right-circularly polarized blue light (e.g., 400 nm) with similar intensity, it is desirable to set the retardation value to 300 nm or higher.

[0193] (Example 10) [Synthesis of HPC derivative 9] HPC derivative 9 (hereinafter also referred to as "HPC-AcC / EtE") was synthesized in the same manner as HPC derivative 5, except that the amount of Karenz AOI used was changed to 2.58 g (0.4 equivalents relative to the hydroxyl groups) and the amount of acetyl chloride used was changed to 4.66 g (1.3 equivalents relative to the hydroxyl groups).

[0194] 1 By measuring the 1H-NMR spectrum and based on the assigned peaks, the degree of substitution of the HPC side chain (hydrogen atom in the hydroxyl group) to a group with an unsaturated double bond (i.e., an acryloyl group) and to an acyl group (i.e., an acetyl group) was calculated. HPC derivative 9 had a degree of substitution of 0.02 to the acryloyl group (a group with an unsaturated double bond) and a degree of substitution of 2.85 to the acetyl group (acyl group) (HPC-AcC / EtE (AcC:EtE=0.02:2.85)).

[0195] <Fabrication of liquid crystal material 11> Using the HPC derivative 9, butyl acrylate (BA), and HMPP obtained as described above, a liquid crystal material 11 with an HPC derivative concentration of 75% by mass was prepared.

[0196] <Fabrication of liquid crystal film 13> Similar to Example 1, the liquid crystal material 11 prepared as described above was subjected to shear orientation treatment in a rheometer, and then the liquid crystal material 11 after shear orientation treatment was left to stand for a certain period of time before being irradiated with light to produce a liquid crystal film 13. The conditions for producing the liquid crystal film 13 were a gap d between the parallel plate and the glass plate of 300 μm or 800 μm, and a shear rate of 0.5 s. -1 The shearing time was set to 300 seconds, the waiting time to 200 seconds, and the UV irradiation conditions were set to a wavelength of 365 nm and an intensity of 80 mW / cm². 2 The irradiation time was set to 6 minutes. As a result, the liquid crystal material 11 was cured to obtain a liquid crystal film 13. When the gap d was 300 μm, it was designated as liquid crystal film 13-1, and when the gap d was 800 μm, it was designated as liquid crystal film 13-2. The thickness of liquid crystal film 13-1 was 339 μm, and the thickness of liquid crystal film 13-2 was 821 μm.

[0197] <Measurement of circularly polarized transmission spectrum> The circularly polarized transmission spectra were measured in the same manner as in Example 1 using the liquid crystal films 13-1 and 13-2 obtained in Example 10. The measurement results of the circularly polarized transmission spectra are shown in Figure 17. Figures 17(a) and 17(b) show the changes in the right-circularly polarized and left-circularly polarized spectra of liquid crystal films 13-1 and 13-2 at r=3 mm and r=9 mm, respectively.

[0198] When the circularly polarized transmission spectra of liquid crystal films 13-1 and 13-2 were measured, the reflection wavelength was approximately 540 nm, and the peak intensity decreased as the thickness of the liquid crystal film decreased.

[0199] Next, the retardation of liquid crystal films 13-1 and 13-2 was measured in the same manner as in Example 6, and the birefringence of liquid crystal films 13-1 and 13-2 was determined by dividing the measured retardation value by the thickness of liquid crystal films 13-1 and 13-2. Figure 18 shows the relationship between the distance from the center in a plan view and the retardation for liquid crystal films 13-1 and 13-2. Figure 19 shows the relationship between the distance from the center in a plan view and the birefringence for liquid crystal films 13-1 and 13-2.

[0200] To investigate the relationship between the retardation values ​​of liquid crystal films 13-1 and 13-2 and the peak intensities of left-right circularly polarized light, the ratio of the peak intensities of left-right circularly polarized light was plotted against the retardation value (retardation value at r=1 to 10). The plot results are shown in Figure 20. Similar to Figure 16, the ratio of the peak intensities of left-right circularly polarized light is (I L -I R ) / (I L +I R This is expressed as follows: Here, the transmittance at a wavelength of 680 nm was used as the baseline transmittance.

[0201] As shown in Figure 20, the proportion of reflected left-circularly polarized light gradually increased as the retardation value increased. From around 300 nm in retardation, the ratio of peak intensities remained almost unchanged even as the retardation value increased, and the intensities of reflected left-circularly polarized and right-circularly polarized light were approximately the same. From these results, it can be inferred that to produce a liquid crystal film that reflects both left- and right-circularly polarized green light (e.g., 540 nm) with similar intensity, it is desirable to set the retardation value to 300 nm or higher.

[0202] (Example 11) <Fabrication of liquid crystal material 12> A liquid crystal material 12 with an HPC derivative concentration of 73% by mass was prepared using HPC derivative 9, butyl acrylate (BA), and HMPP obtained in the same manner as in Example 10.

[0203] <Fabrication of LCD film 14> Similar to Example 1, the liquid crystal material 12 prepared as described above was subjected to shear orientation treatment in a rheometer, and then the liquid crystal material 12 after shear orientation treatment was left to stand for a certain period of time before being irradiated with light to produce a liquid crystal film 14. The conditions for producing the liquid crystal film 14 were the same as in Example 10. Liquid crystal film 14-1 was produced when the gap d was 300 μm, and liquid crystal film 14-2 was produced when the gap d was 800 μm. The thickness of liquid crystal film 14-1 was 345 μm, and the thickness of liquid crystal film 14-2 was 803 μm.

[0204] <Measurement of circularly polarized transmission spectrum> The circularly polarized transmission spectra were measured in the same manner as in Example 1 using the liquid crystal films 14-1 and 14-2 obtained in Example 11. The measurement results of the circularly polarized transmission spectra are shown in Figure 21. Figures 21(a) and 21(b) show the changes in the right-circularly polarized and left-circularly polarized spectra of liquid crystal films 14-1 and 14-2 at r=3 mm and r=9 mm, respectively.

[0205] When the circularly polarized transmission spectra of liquid crystal films 14-1 and 14-2 were measured, the reflection wavelength was approximately 610 nm, and the peak intensity decreased as the thickness of the liquid crystal film decreased.

[0206] Next, the retardation of liquid crystal films 14-1 and 14-2 was measured in the same manner as in Example 6, and the birefringence of liquid crystal films 14-1 and 14-2 was determined by dividing the measured retardation value by the thickness of liquid crystal films 14-1 and 14-2. Figure 22 shows the relationship between the distance from the center in a plan view and the retardation for liquid crystal films 14-1 and 14-2. Figure 23 shows the relationship between the distance from the center in a plan view and the birefringence for liquid crystal films 14-1 and 14-2.

[0207] To investigate the relationship between the retardation values ​​of liquid crystal films 14-1 and 14-2 and the peak intensities of left-right circularly polarized light, the ratio of the peak intensities of left-right circularly polarized light was plotted against the retardation value (retardation value at r=1 to 10). The plot results are shown in Figure 24. Similar to Figure 16, the ratio of the peak intensities of left-right circularly polarized light is (I L -I R ) / (I L +I R This is expressed as follows: Here, the transmittance at a wavelength of 720 nm was used as the baseline transmittance.

[0208] As shown in Figure 24, the proportion of reflected left-circularly polarized light gradually increased as the retardation value increased. From around 300 nm in retardation, the ratio of peak intensities remained almost unchanged even as the retardation value increased, and the intensities of reflected left-circularly polarized and right-circularly polarized light were approximately the same. From these results, it can be inferred that to produce a liquid crystal film that reflects both left- and right-circularly polarized red light (e.g., 610 nm) with similar intensity, it is desirable to set the retardation value to 300 nm or higher.

[0209] (Example 12) [Synthesis of HPC derivative 10] The HPC solution was shielded from light with aluminum foil, and 1.29 g of Karenz AOI (2-isocyanatoethyl acrylate, manufactured by Showa Denko K.K., registered trademark) (0.2 equivalents relative to the hydroxyl groups) was added at room temperature and in the dark. After that, 4.66 g of acetyl chloride (1.3 equivalents relative to the hydroxyl groups) was added and the reaction was continued for a further 22 hours. After the reaction was complete, HPC derivative 10 (hereinafter also referred to as "HPC-AcC / EtE") was obtained by performing the same procedure as in Example 1 to obtain HPC derivative 1.

[0210] 1 By measuring the 1H-NMR spectrum and based on the assigned peaks, the degree of substitution of the HPC side chain (hydrogen atom in the hydroxyl group) to a group with an unsaturated double bond (i.e., an acryloyl group) and to an acyl group (i.e., an acetyl group) was calculated. HPC derivative 10 had a degree of substitution of 0.03 to the acryloyl group (a group with an unsaturated double bond) and a degree of substitution of 2.87 to the acetyl group (acyl group) (HPC-AcC / EtE (AcC:EtE=0.03:2.87)).

[0211] <Fabrication of liquid crystal material 13> Using the HPC derivative 10 obtained as described above, butyl acrylate (BA), and HMPP, a liquid crystal material 13 with an HPC derivative concentration of 78.2% by mass was prepared.

[0212] <Production of liquid crystal film 15> Similar to Example 1, the liquid crystal material 13 prepared as described above was subjected to shear orientation treatment in a rheometer, and then the liquid crystal material 13 after shear orientation treatment was left to stand for a certain period of time before being irradiated with light to produce a liquid crystal film 15. The conditions for producing the liquid crystal film 15 were a gap d between the parallel plate and the glass plate of 500 μm and a shear rate of 5 s. -1 The shearing time was set to 300 seconds, the waiting time to 200 seconds, and the UV irradiation conditions were set to a wavelength of 365 nm and an intensity of 80 mW / cm². 2 The irradiation time was set to 6 minutes. As a result, the liquid crystal material 13 was cured to obtain a liquid crystal film 15.

[0213] <Measurement of circularly polarized transmission spectrum> The circularly polarized transmission spectrum was measured using the liquid crystal film 15 obtained in Example 12 in the same manner as in Example 1. The measurement results of the circularly polarized transmission spectrum are shown in Figures 25 and 26. Figures 25(a) and 25(b) show the changes in the left and right circularly polarized spectra of the liquid crystal film 15 at r=0mm, 3mm, 6mm, and 9mm, respectively. Figure 26 shows the changes in the left circularly polarized spectrum of the liquid crystal film 15 from r=0mm to 5mm.

[0214] When the circularly polarized transmission spectrum of the liquid crystal film 15 was measured, the reflection wavelength was approximately 450 nm to 480 nm. As shown in Figure 25(b), a reflection peak of right-circular polarization was observed throughout the entire sample (in the region r=0 to 9 mm). On the other hand, as shown in Figures 25(a) and 26, a reflection peak of left-circular polarization was observed near the center of the sample (in the region r=0 to 3 mm), and in particular, a reflection peak of left-circular polarization with an intensity similar to that of the reflection peak of right-circular polarization was observed in the region r≦2 mm. The shear rate used to manufacture the liquid crystal film 15 was 5 s. -1 This value represents the shear rate at the outer circumference (r=12.5mm), therefore, the shear rate in the region r≦2mm is 0.8s. -1 The following is calculated:

[0215] The retardation of the liquid crystal film 15 was measured in the same manner as in Example 6. Figure 27 shows the relationship between the distance from the center in a plan view and the retardation of the liquid crystal film 15. As shown in Figure 27, in the region r≦1, the retardation value increased as the value of r increased, in the region r>1, the retardation value decreased as the value of r increased, and in the region r≧6, the retardation value became almost constant.

[0216] From the results in Figures 25 to 27, it is presumed that the disappearance of the left-circularly polarized reflection peak due to an increase in r, i.e., an increase in shear rate, is due to a decrease in the retardation value. It is presumed that if the retardation value is 300 nm or higher, it will be easier to manufacture a liquid crystal film that reflects both left and right circularly polarized light with similar intensity. Even when r=0 mm and the retardation value is almost 0, the reason why the reflection intensity of left-circularly polarized light is high is that only at the r=0 mm position, the shear rate is 0 s. -1 This suggests that the orientation of liquid crystal molecules at the r=0mm position is disrupted by surrounding shear.

[0217] (Example 13) Using the HPC derivative 10 synthesized as described above, the preferred orientation time was investigated.

[0218] <Fabrication of liquid crystal materials 13 and 14> Using the HPC derivative 10, butyl acrylate (BA), and HMPP obtained as described above, a liquid crystal material 13 (same as the liquid crystal material 13 of Example 12) with an HPC derivative concentration of 78.2% by mass was prepared. Furthermore, a liquid crystal material 14 with an HPC derivative concentration of 77.8% by mass was prepared using the HPC derivative 10 obtained as described above, butyl acrylate (BA), and HMPP.

[0219] <Preparation of LCD films 16-18> Similar to Example 1, the liquid crystal material 13 prepared as described above was subjected to shear orientation treatment in a rheometer, and then the liquid crystal material 13 after shear orientation treatment was left to stand for a certain period of time before being irradiated with light to produce a liquid crystal film 16. The conditions for producing the liquid crystal film 16 were a gap d between the parallel plate and the glass plate of 500 μm and a shear rate of 0.5 s. -1 The shearing treatment time was set to 300 seconds, the waiting time to 10 seconds, and the UV irradiation conditions were set to a wavelength of 365 nm and an intensity of 80 mW / cm². 2 The irradiation time was set to 6 minutes. As a result, the liquid crystal material 13 was cured to obtain a liquid crystal film 16. Furthermore, the liquid crystal material 14 was subjected to a shear orientation treatment, and then the liquid crystal material 14 after the shear orientation treatment was left to stand for a certain period of time before being irradiated with light to produce liquid crystal films 17 and 18. The production conditions for liquid crystal films 17 and 18 were the same as those for liquid crystal film 16, except that the liquid crystal material 14 was used and the waiting time was set to 100 seconds or 1200 seconds. Liquid crystal film 17 was produced with a waiting time of 100 seconds, and liquid crystal film 18 was produced with a waiting time of 1200 seconds.

[0220] <Measurement of circularly polarized transmission spectrum> The circularly polarized transmission spectra were measured using the liquid crystal films 16-18 obtained in Example 13 in the same manner as in Example 1. The measurement results of the circularly polarized transmission spectra are shown in Figure 28. Figures 28(a) and 28(b) show the changes in the left circularly polarized spectra of liquid crystal films 16-18 at r=4mm or r=9mm. Figures 28(c) and 28(d) show the changes in the right circularly polarized spectra of liquid crystal films 16-18 at r=4mm or r=9mm.

[0221] As shown in Figure 28, the peak of the circularly polarized transmission spectrum tended to become sharper with increasing orientation time. Furthermore, the reflection wavelength remained almost constant regardless of orientation time, and the reflection intensity from liquid crystal films 16-18 was maintained even at a long orientation time of 1200 seconds. Since the peak width did not change significantly between orientation times of 100 seconds and 1200 seconds, it is presumed that an orientation time of around 200 seconds is sufficient.

[0222] The retardation of liquid crystal films 16-18 was measured in the same manner as in Example 6. Figure 29 shows the relationship between the distance from the center in a plan view and the retardation for liquid crystal films 16-18. As shown in Figure 29, the retardation value tended to be maintained even when the orientation time was long.

[0223] (Reference example 1) A liquid crystal film 19 was fabricated by irradiating the liquid crystal material 1 prepared in Example 1 with light without subjecting it to shear orientation treatment. Specifically, the liquid crystal material 1 was sandwiched between a slide glass (2.5 cm x 2.5 cm) with a release sheet attached, along with a 0.5 mm thick PTFE spacer. After being left to stand for about 30 minutes to allow for orientation, an LED light source was used with a wavelength of 365 nm and an intensity of 80 mW / cm². 2 A liquid crystal film 19 was fabricated by irradiating it with ultraviolet light for 6 minutes.

[0224] <Measurement of circularly polarized transmission spectrum> The circularly polarized transmission spectrum was measured using the liquid crystal film 19 obtained in Reference Example 1 (thickness of liquid crystal film 19: approximately 500 μm). The measurement results of the circularly polarized transmission spectrum in Reference Example 1 are shown in Figure 30. As shown in Figure 30, in the liquid crystal film 19 that had not undergone shear orientation treatment, the reflection of right-circularly polarized light was clearly observed, but the reflection of left-circularly polarized light could not be observed. On the other hand, as shown in Figures 1 and 2, in the liquid crystal film 1 that used the liquid crystal material 1 and underwent shear orientation treatment, the reflection of both right-circularly polarized and left-circularly polarized light could be observed. Thus, the change in polarization characteristics due to shear orientation treatment was confirmed.

[0225] (Example 14) [Synthesis of EC derivative 1] EC derivative 1 was synthesized according to the following scheme. 13.3 mL of anhydrous tetrahydrofuran was added to a 100 mL round-bottom flask filled with nitrogen, and then 2.0 g (amount of substance in monomer units: 8.9 mmol) of ethylcellulose (EC) was weighed and dissolved in the anhydrous tetrahydrofuran with stirring to obtain an EC solution.

[0226] The EC solution was covered with aluminum foil to protect it from light, and 3.6 g (26 mmol) of Karenz AOI (2-isocyanatoethyl acrylate, manufactured by Showa Denko K.K., registered trademark) was added at room temperature. The mixture was then reacted at room temperature in the dark for 24 hours. After the reaction was complete, EC derivative 1 (hereinafter also referred to as "EC-AcC") was obtained by purification in the same manner as for HPC derivative 1.

[0227] [ka]

[0228] 1 ¹H-NMR spectra were measured, and based on the assigned peaks, the degree of substitution of the EC side chain (hydrogen atom in the hydroxyl group) to a group with an unsaturated double bond (i.e., an acryloyl group) and to an acyl group (i.e., an ethyl group) was calculated. HPC derivative 3 had a degree of substitution of 0.05 to the acryloyl group (a group with an unsaturated double bond) and a degree of substitution of 2.50 to the ethyl group (acyl group).

[0229] <Fabrication of liquid crystal material A> Liquid crystal material A was prepared using EC derivative 1, acrylic acid (AA), and HMPP obtained as described above. Specifically, EC derivative 1, AA, and HMPP were thoroughly mixed in a mass ratio of 49.7:49.5:0.8, and then degassed under vacuum for a short time to prepare liquid crystal material A.

[0230] <Preparation of liquid crystal film A> In a rheometer, the liquid crystal material A prepared as described above was subjected to shear orientation treatment, and then, after the shear orientation treatment, the liquid crystal material A was left to stand for a certain period of time before being irradiated with light to produce a liquid crystal film A. Specifically, a rheometer was prepared that had a 25 mm diameter parallel plate as an upper jig and a glass plate equipped with a Peltier element as a lower jig, and that could irradiate ultraviolet light from the lower jig side. Release sheets were attached to the upper and lower jigs. Liquid crystal material A was placed on a glass plate adjusted to 25°C, and the liquid crystal material A was sandwiched between the parallel plate and the glass plate. At this time, the gap d between the parallel plate and the glass plate was set to 500 μm. A shear rate of 0.2 s was applied to the liquid crystal material A sandwiched between the parallel plate and the glass plate. -1 Shear orientation treatment was performed for 300 seconds under the specified conditions. The shear rate increased proportionally to the distance from the center in a plan view, and in this experiment, the shear rate at the position furthest from the center (i.e., distance r: 12.5 mm from the center) was adjusted to the above value. The liquid crystal material A after the shear orientation treatment was left to stand for 600 seconds. After the standing period, an LED light source was used on the liquid crystal material A with a wavelength of 365 nm and an intensity of 80 mW / cm². 2 The liquid crystal material A was irradiated with ultraviolet light for 6 minutes. Through this process, liquid crystal film A was obtained by curing the liquid crystal material A.

[0231] <Preparation of liquid crystal film B> In the fabrication of the aforementioned liquid crystal film A, liquid crystal film B was obtained by curing liquid crystal material A without performing shear orientation treatment and subsequent waiting. Specifically, liquid crystal material A was sandwiched between a slide glass (2.5 cm x 2.5 cm) with a release sheet attached, along with a 0.5 mm thick PTFE spacer. Then, it was left to stand for about 30 minutes to orient, and then an LED light source was used with a wavelength of 365 nm and an intensity of 80 mW / cm². 2 Liquid crystal film B was fabricated by irradiating it with ultraviolet light for 6 minutes.

[0232] <Measurement of circularly polarized transmission spectrum> The circularly polarized transmission spectra were measured using liquid crystal film A (thickness of liquid crystal film A: approximately 500 μm) and liquid crystal film B (thickness of liquid crystal film A: approximately 500 μm) in the same manner as for liquid crystal film 1. The measurement results of the circularly polarized transmission spectra are shown in Figures 31 and 32.

[0233] As shown in Figure 31, it was confirmed that liquid crystal film A, which had undergone shear orientation treatment, reflected both right-circularly polarized and left-circularly polarized light. On the other hand, as shown in Figure 32, in liquid crystal film B, which had not undergone shear orientation treatment, left-circularly polarized light was observed, but right-circularly polarized light was not. The reflection wavelength of liquid crystal film B was 489 nm.

[0234] Normally, when a liquid crystal film is made using an acrylic acid solution of EC derivative 1, a liquid crystal film that reflects only left-circularly polarized light is obtained, as shown in Figure 32. On the other hand, when a liquid crystal film is made using an acrylic acid solution of EC derivative 1 and subjected to shear orientation treatment, a liquid crystal film that reflects both left-circularly polarized and right-circularly polarized light can be obtained, as shown in Figure 31.

[0235] The results above demonstrate that a liquid crystal film that reflects both left-circularly polarized and right-circularly polarized light can be obtained by using an HPC derivative or an EC derivative and applying a shear orientation treatment to fabricate the liquid crystal film. It is also presumed that a liquid crystal film that reflects both left-circularly polarized and right-circularly polarized light can be obtained by applying a shear orientation treatment to fabricate the liquid crystal film even when using a cellulose derivative other than an HPC derivative or an EC derivative.

Claims

1. A step of preparing a cellulose derivative comprising hydroxyl groups, wherein at least some of the hydrogen atoms of the hydroxyl groups are substituted with a group having an unsaturated double bond, and at least some of the hydrogen atoms of the other hydroxyl groups are substituted with an alkyl group, A step of preparing a liquid crystal material comprising the cellulose derivative and a polymerizable monomer containing a group having an unsaturated double bond, A shearing step in which shear force is applied to the liquid crystal material, An orientation step in which the liquid crystal material after the shearing step is left to stand and orient, The process includes a curing step for curing the liquid crystal material after the orientation step, The cellulose derivative has a terminal (meth)acryloyl group linked via a divalent -O-C(=O)-NH- group as the group having the unsaturated double bond, The standing time in the orientation process is 10 seconds to 5 hours. A method for manufacturing a liquid crystal film having both left-circularly polarized and right-circularly polarized reflection characteristics.

2. The method for manufacturing a liquid crystal film according to Claim 1, wherein the standing time in the orientation step is 10 seconds to 30 minutes.

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